linux-stable/fs/io_uring.c
Hillf Danton f26c08b444 io_uring: fix file leak on error path of io ctx creation
Put file as part of error handling when setting up io ctx to fix
memory leaks like the following one.

   BUG: memory leak
   unreferenced object 0xffff888101ea2200 (size 256):
     comm "syz-executor355", pid 8470, jiffies 4294953658 (age 32.400s)
     hex dump (first 32 bytes):
       00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00  ................
       20 59 03 01 81 88 ff ff 80 87 a8 10 81 88 ff ff   Y..............
     backtrace:
       [<000000002e0a7c5f>] kmem_cache_zalloc include/linux/slab.h:654 [inline]
       [<000000002e0a7c5f>] __alloc_file+0x1f/0x130 fs/file_table.c:101
       [<000000001a55b73a>] alloc_empty_file+0x69/0x120 fs/file_table.c:151
       [<00000000fb22349e>] alloc_file+0x33/0x1b0 fs/file_table.c:193
       [<000000006e1465bb>] alloc_file_pseudo+0xb2/0x140 fs/file_table.c:233
       [<000000007118092a>] anon_inode_getfile fs/anon_inodes.c:91 [inline]
       [<000000007118092a>] anon_inode_getfile+0xaa/0x120 fs/anon_inodes.c:74
       [<000000002ae99012>] io_uring_get_fd fs/io_uring.c:9198 [inline]
       [<000000002ae99012>] io_uring_create fs/io_uring.c:9377 [inline]
       [<000000002ae99012>] io_uring_setup+0x1125/0x1630 fs/io_uring.c:9411
       [<000000008280baad>] do_syscall_64+0x2d/0x70 arch/x86/entry/common.c:46
       [<00000000685d8cf0>] entry_SYSCALL_64_after_hwframe+0x44/0xa9

Reported-by: syzbot+71c4697e27c99fddcf17@syzkaller.appspotmail.com
Fixes: 0f2122045b ("io_uring: don't rely on weak ->files references")
Cc: Pavel Begunkov <asml.silence@gmail.com>
Signed-off-by: Hillf Danton <hdanton@sina.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2020-12-08 08:54:26 -07:00

9808 lines
236 KiB
C

// SPDX-License-Identifier: GPL-2.0
/*
* Shared application/kernel submission and completion ring pairs, for
* supporting fast/efficient IO.
*
* A note on the read/write ordering memory barriers that are matched between
* the application and kernel side.
*
* After the application reads the CQ ring tail, it must use an
* appropriate smp_rmb() to pair with the smp_wmb() the kernel uses
* before writing the tail (using smp_load_acquire to read the tail will
* do). It also needs a smp_mb() before updating CQ head (ordering the
* entry load(s) with the head store), pairing with an implicit barrier
* through a control-dependency in io_get_cqring (smp_store_release to
* store head will do). Failure to do so could lead to reading invalid
* CQ entries.
*
* Likewise, the application must use an appropriate smp_wmb() before
* writing the SQ tail (ordering SQ entry stores with the tail store),
* which pairs with smp_load_acquire in io_get_sqring (smp_store_release
* to store the tail will do). And it needs a barrier ordering the SQ
* head load before writing new SQ entries (smp_load_acquire to read
* head will do).
*
* When using the SQ poll thread (IORING_SETUP_SQPOLL), the application
* needs to check the SQ flags for IORING_SQ_NEED_WAKEUP *after*
* updating the SQ tail; a full memory barrier smp_mb() is needed
* between.
*
* Also see the examples in the liburing library:
*
* git://git.kernel.dk/liburing
*
* io_uring also uses READ/WRITE_ONCE() for _any_ store or load that happens
* from data shared between the kernel and application. This is done both
* for ordering purposes, but also to ensure that once a value is loaded from
* data that the application could potentially modify, it remains stable.
*
* Copyright (C) 2018-2019 Jens Axboe
* Copyright (c) 2018-2019 Christoph Hellwig
*/
#include <linux/kernel.h>
#include <linux/init.h>
#include <linux/errno.h>
#include <linux/syscalls.h>
#include <linux/compat.h>
#include <net/compat.h>
#include <linux/refcount.h>
#include <linux/uio.h>
#include <linux/bits.h>
#include <linux/sched/signal.h>
#include <linux/fs.h>
#include <linux/file.h>
#include <linux/fdtable.h>
#include <linux/mm.h>
#include <linux/mman.h>
#include <linux/percpu.h>
#include <linux/slab.h>
#include <linux/kthread.h>
#include <linux/blkdev.h>
#include <linux/bvec.h>
#include <linux/net.h>
#include <net/sock.h>
#include <net/af_unix.h>
#include <net/scm.h>
#include <linux/anon_inodes.h>
#include <linux/sched/mm.h>
#include <linux/uaccess.h>
#include <linux/nospec.h>
#include <linux/sizes.h>
#include <linux/hugetlb.h>
#include <linux/highmem.h>
#include <linux/namei.h>
#include <linux/fsnotify.h>
#include <linux/fadvise.h>
#include <linux/eventpoll.h>
#include <linux/fs_struct.h>
#include <linux/splice.h>
#include <linux/task_work.h>
#include <linux/pagemap.h>
#include <linux/io_uring.h>
#include <linux/blk-cgroup.h>
#include <linux/audit.h>
#define CREATE_TRACE_POINTS
#include <trace/events/io_uring.h>
#include <uapi/linux/io_uring.h>
#include "internal.h"
#include "io-wq.h"
#define IORING_MAX_ENTRIES 32768
#define IORING_MAX_CQ_ENTRIES (2 * IORING_MAX_ENTRIES)
/*
* Shift of 9 is 512 entries, or exactly one page on 64-bit archs
*/
#define IORING_FILE_TABLE_SHIFT 9
#define IORING_MAX_FILES_TABLE (1U << IORING_FILE_TABLE_SHIFT)
#define IORING_FILE_TABLE_MASK (IORING_MAX_FILES_TABLE - 1)
#define IORING_MAX_FIXED_FILES (64 * IORING_MAX_FILES_TABLE)
#define IORING_MAX_RESTRICTIONS (IORING_RESTRICTION_LAST + \
IORING_REGISTER_LAST + IORING_OP_LAST)
struct io_uring {
u32 head ____cacheline_aligned_in_smp;
u32 tail ____cacheline_aligned_in_smp;
};
/*
* This data is shared with the application through the mmap at offsets
* IORING_OFF_SQ_RING and IORING_OFF_CQ_RING.
*
* The offsets to the member fields are published through struct
* io_sqring_offsets when calling io_uring_setup.
*/
struct io_rings {
/*
* Head and tail offsets into the ring; the offsets need to be
* masked to get valid indices.
*
* The kernel controls head of the sq ring and the tail of the cq ring,
* and the application controls tail of the sq ring and the head of the
* cq ring.
*/
struct io_uring sq, cq;
/*
* Bitmasks to apply to head and tail offsets (constant, equals
* ring_entries - 1)
*/
u32 sq_ring_mask, cq_ring_mask;
/* Ring sizes (constant, power of 2) */
u32 sq_ring_entries, cq_ring_entries;
/*
* Number of invalid entries dropped by the kernel due to
* invalid index stored in array
*
* Written by the kernel, shouldn't be modified by the
* application (i.e. get number of "new events" by comparing to
* cached value).
*
* After a new SQ head value was read by the application this
* counter includes all submissions that were dropped reaching
* the new SQ head (and possibly more).
*/
u32 sq_dropped;
/*
* Runtime SQ flags
*
* Written by the kernel, shouldn't be modified by the
* application.
*
* The application needs a full memory barrier before checking
* for IORING_SQ_NEED_WAKEUP after updating the sq tail.
*/
u32 sq_flags;
/*
* Runtime CQ flags
*
* Written by the application, shouldn't be modified by the
* kernel.
*/
u32 cq_flags;
/*
* Number of completion events lost because the queue was full;
* this should be avoided by the application by making sure
* there are not more requests pending than there is space in
* the completion queue.
*
* Written by the kernel, shouldn't be modified by the
* application (i.e. get number of "new events" by comparing to
* cached value).
*
* As completion events come in out of order this counter is not
* ordered with any other data.
*/
u32 cq_overflow;
/*
* Ring buffer of completion events.
*
* The kernel writes completion events fresh every time they are
* produced, so the application is allowed to modify pending
* entries.
*/
struct io_uring_cqe cqes[] ____cacheline_aligned_in_smp;
};
struct io_mapped_ubuf {
u64 ubuf;
size_t len;
struct bio_vec *bvec;
unsigned int nr_bvecs;
unsigned long acct_pages;
};
struct fixed_file_table {
struct file **files;
};
struct fixed_file_ref_node {
struct percpu_ref refs;
struct list_head node;
struct list_head file_list;
struct fixed_file_data *file_data;
struct llist_node llist;
bool done;
};
struct fixed_file_data {
struct fixed_file_table *table;
struct io_ring_ctx *ctx;
struct fixed_file_ref_node *node;
struct percpu_ref refs;
struct completion done;
struct list_head ref_list;
spinlock_t lock;
};
struct io_buffer {
struct list_head list;
__u64 addr;
__s32 len;
__u16 bid;
};
struct io_restriction {
DECLARE_BITMAP(register_op, IORING_REGISTER_LAST);
DECLARE_BITMAP(sqe_op, IORING_OP_LAST);
u8 sqe_flags_allowed;
u8 sqe_flags_required;
bool registered;
};
struct io_sq_data {
refcount_t refs;
struct mutex lock;
/* ctx's that are using this sqd */
struct list_head ctx_list;
struct list_head ctx_new_list;
struct mutex ctx_lock;
struct task_struct *thread;
struct wait_queue_head wait;
};
struct io_ring_ctx {
struct {
struct percpu_ref refs;
} ____cacheline_aligned_in_smp;
struct {
unsigned int flags;
unsigned int compat: 1;
unsigned int limit_mem: 1;
unsigned int cq_overflow_flushed: 1;
unsigned int drain_next: 1;
unsigned int eventfd_async: 1;
unsigned int restricted: 1;
/*
* Ring buffer of indices into array of io_uring_sqe, which is
* mmapped by the application using the IORING_OFF_SQES offset.
*
* This indirection could e.g. be used to assign fixed
* io_uring_sqe entries to operations and only submit them to
* the queue when needed.
*
* The kernel modifies neither the indices array nor the entries
* array.
*/
u32 *sq_array;
unsigned cached_sq_head;
unsigned sq_entries;
unsigned sq_mask;
unsigned sq_thread_idle;
unsigned cached_sq_dropped;
unsigned cached_cq_overflow;
unsigned long sq_check_overflow;
struct list_head defer_list;
struct list_head timeout_list;
struct list_head cq_overflow_list;
wait_queue_head_t inflight_wait;
struct io_uring_sqe *sq_sqes;
} ____cacheline_aligned_in_smp;
struct io_rings *rings;
/* IO offload */
struct io_wq *io_wq;
/*
* For SQPOLL usage - we hold a reference to the parent task, so we
* have access to the ->files
*/
struct task_struct *sqo_task;
/* Only used for accounting purposes */
struct mm_struct *mm_account;
#ifdef CONFIG_BLK_CGROUP
struct cgroup_subsys_state *sqo_blkcg_css;
#endif
struct io_sq_data *sq_data; /* if using sq thread polling */
struct wait_queue_head sqo_sq_wait;
struct wait_queue_entry sqo_wait_entry;
struct list_head sqd_list;
/*
* If used, fixed file set. Writers must ensure that ->refs is dead,
* readers must ensure that ->refs is alive as long as the file* is
* used. Only updated through io_uring_register(2).
*/
struct fixed_file_data *file_data;
unsigned nr_user_files;
/* if used, fixed mapped user buffers */
unsigned nr_user_bufs;
struct io_mapped_ubuf *user_bufs;
struct user_struct *user;
const struct cred *creds;
#ifdef CONFIG_AUDIT
kuid_t loginuid;
unsigned int sessionid;
#endif
struct completion ref_comp;
struct completion sq_thread_comp;
/* if all else fails... */
struct io_kiocb *fallback_req;
#if defined(CONFIG_UNIX)
struct socket *ring_sock;
#endif
struct idr io_buffer_idr;
struct idr personality_idr;
struct {
unsigned cached_cq_tail;
unsigned cq_entries;
unsigned cq_mask;
atomic_t cq_timeouts;
unsigned long cq_check_overflow;
struct wait_queue_head cq_wait;
struct fasync_struct *cq_fasync;
struct eventfd_ctx *cq_ev_fd;
} ____cacheline_aligned_in_smp;
struct {
struct mutex uring_lock;
wait_queue_head_t wait;
} ____cacheline_aligned_in_smp;
struct {
spinlock_t completion_lock;
/*
* ->iopoll_list is protected by the ctx->uring_lock for
* io_uring instances that don't use IORING_SETUP_SQPOLL.
* For SQPOLL, only the single threaded io_sq_thread() will
* manipulate the list, hence no extra locking is needed there.
*/
struct list_head iopoll_list;
struct hlist_head *cancel_hash;
unsigned cancel_hash_bits;
bool poll_multi_file;
spinlock_t inflight_lock;
struct list_head inflight_list;
} ____cacheline_aligned_in_smp;
struct delayed_work file_put_work;
struct llist_head file_put_llist;
struct work_struct exit_work;
struct io_restriction restrictions;
};
/*
* First field must be the file pointer in all the
* iocb unions! See also 'struct kiocb' in <linux/fs.h>
*/
struct io_poll_iocb {
struct file *file;
union {
struct wait_queue_head *head;
u64 addr;
};
__poll_t events;
bool done;
bool canceled;
struct wait_queue_entry wait;
};
struct io_close {
struct file *file;
struct file *put_file;
int fd;
};
struct io_timeout_data {
struct io_kiocb *req;
struct hrtimer timer;
struct timespec64 ts;
enum hrtimer_mode mode;
};
struct io_accept {
struct file *file;
struct sockaddr __user *addr;
int __user *addr_len;
int flags;
unsigned long nofile;
};
struct io_sync {
struct file *file;
loff_t len;
loff_t off;
int flags;
int mode;
};
struct io_cancel {
struct file *file;
u64 addr;
};
struct io_timeout {
struct file *file;
u32 off;
u32 target_seq;
struct list_head list;
};
struct io_timeout_rem {
struct file *file;
u64 addr;
};
struct io_rw {
/* NOTE: kiocb has the file as the first member, so don't do it here */
struct kiocb kiocb;
u64 addr;
u64 len;
};
struct io_connect {
struct file *file;
struct sockaddr __user *addr;
int addr_len;
};
struct io_sr_msg {
struct file *file;
union {
struct user_msghdr __user *umsg;
void __user *buf;
};
int msg_flags;
int bgid;
size_t len;
struct io_buffer *kbuf;
};
struct io_open {
struct file *file;
int dfd;
bool ignore_nonblock;
struct filename *filename;
struct open_how how;
unsigned long nofile;
};
struct io_files_update {
struct file *file;
u64 arg;
u32 nr_args;
u32 offset;
};
struct io_fadvise {
struct file *file;
u64 offset;
u32 len;
u32 advice;
};
struct io_madvise {
struct file *file;
u64 addr;
u32 len;
u32 advice;
};
struct io_epoll {
struct file *file;
int epfd;
int op;
int fd;
struct epoll_event event;
};
struct io_splice {
struct file *file_out;
struct file *file_in;
loff_t off_out;
loff_t off_in;
u64 len;
unsigned int flags;
};
struct io_provide_buf {
struct file *file;
__u64 addr;
__s32 len;
__u32 bgid;
__u16 nbufs;
__u16 bid;
};
struct io_statx {
struct file *file;
int dfd;
unsigned int mask;
unsigned int flags;
const char __user *filename;
struct statx __user *buffer;
};
struct io_completion {
struct file *file;
struct list_head list;
int cflags;
};
struct io_async_connect {
struct sockaddr_storage address;
};
struct io_async_msghdr {
struct iovec fast_iov[UIO_FASTIOV];
struct iovec *iov;
struct sockaddr __user *uaddr;
struct msghdr msg;
struct sockaddr_storage addr;
};
struct io_async_rw {
struct iovec fast_iov[UIO_FASTIOV];
const struct iovec *free_iovec;
struct iov_iter iter;
size_t bytes_done;
struct wait_page_queue wpq;
};
enum {
REQ_F_FIXED_FILE_BIT = IOSQE_FIXED_FILE_BIT,
REQ_F_IO_DRAIN_BIT = IOSQE_IO_DRAIN_BIT,
REQ_F_LINK_BIT = IOSQE_IO_LINK_BIT,
REQ_F_HARDLINK_BIT = IOSQE_IO_HARDLINK_BIT,
REQ_F_FORCE_ASYNC_BIT = IOSQE_ASYNC_BIT,
REQ_F_BUFFER_SELECT_BIT = IOSQE_BUFFER_SELECT_BIT,
REQ_F_LINK_HEAD_BIT,
REQ_F_FAIL_LINK_BIT,
REQ_F_INFLIGHT_BIT,
REQ_F_CUR_POS_BIT,
REQ_F_NOWAIT_BIT,
REQ_F_LINK_TIMEOUT_BIT,
REQ_F_ISREG_BIT,
REQ_F_NEED_CLEANUP_BIT,
REQ_F_POLLED_BIT,
REQ_F_BUFFER_SELECTED_BIT,
REQ_F_NO_FILE_TABLE_BIT,
REQ_F_WORK_INITIALIZED_BIT,
REQ_F_LTIMEOUT_ACTIVE_BIT,
/* not a real bit, just to check we're not overflowing the space */
__REQ_F_LAST_BIT,
};
enum {
/* ctx owns file */
REQ_F_FIXED_FILE = BIT(REQ_F_FIXED_FILE_BIT),
/* drain existing IO first */
REQ_F_IO_DRAIN = BIT(REQ_F_IO_DRAIN_BIT),
/* linked sqes */
REQ_F_LINK = BIT(REQ_F_LINK_BIT),
/* doesn't sever on completion < 0 */
REQ_F_HARDLINK = BIT(REQ_F_HARDLINK_BIT),
/* IOSQE_ASYNC */
REQ_F_FORCE_ASYNC = BIT(REQ_F_FORCE_ASYNC_BIT),
/* IOSQE_BUFFER_SELECT */
REQ_F_BUFFER_SELECT = BIT(REQ_F_BUFFER_SELECT_BIT),
/* head of a link */
REQ_F_LINK_HEAD = BIT(REQ_F_LINK_HEAD_BIT),
/* fail rest of links */
REQ_F_FAIL_LINK = BIT(REQ_F_FAIL_LINK_BIT),
/* on inflight list */
REQ_F_INFLIGHT = BIT(REQ_F_INFLIGHT_BIT),
/* read/write uses file position */
REQ_F_CUR_POS = BIT(REQ_F_CUR_POS_BIT),
/* must not punt to workers */
REQ_F_NOWAIT = BIT(REQ_F_NOWAIT_BIT),
/* has or had linked timeout */
REQ_F_LINK_TIMEOUT = BIT(REQ_F_LINK_TIMEOUT_BIT),
/* regular file */
REQ_F_ISREG = BIT(REQ_F_ISREG_BIT),
/* needs cleanup */
REQ_F_NEED_CLEANUP = BIT(REQ_F_NEED_CLEANUP_BIT),
/* already went through poll handler */
REQ_F_POLLED = BIT(REQ_F_POLLED_BIT),
/* buffer already selected */
REQ_F_BUFFER_SELECTED = BIT(REQ_F_BUFFER_SELECTED_BIT),
/* doesn't need file table for this request */
REQ_F_NO_FILE_TABLE = BIT(REQ_F_NO_FILE_TABLE_BIT),
/* io_wq_work is initialized */
REQ_F_WORK_INITIALIZED = BIT(REQ_F_WORK_INITIALIZED_BIT),
/* linked timeout is active, i.e. prepared by link's head */
REQ_F_LTIMEOUT_ACTIVE = BIT(REQ_F_LTIMEOUT_ACTIVE_BIT),
};
struct async_poll {
struct io_poll_iocb poll;
struct io_poll_iocb *double_poll;
};
/*
* NOTE! Each of the iocb union members has the file pointer
* as the first entry in their struct definition. So you can
* access the file pointer through any of the sub-structs,
* or directly as just 'ki_filp' in this struct.
*/
struct io_kiocb {
union {
struct file *file;
struct io_rw rw;
struct io_poll_iocb poll;
struct io_accept accept;
struct io_sync sync;
struct io_cancel cancel;
struct io_timeout timeout;
struct io_timeout_rem timeout_rem;
struct io_connect connect;
struct io_sr_msg sr_msg;
struct io_open open;
struct io_close close;
struct io_files_update files_update;
struct io_fadvise fadvise;
struct io_madvise madvise;
struct io_epoll epoll;
struct io_splice splice;
struct io_provide_buf pbuf;
struct io_statx statx;
/* use only after cleaning per-op data, see io_clean_op() */
struct io_completion compl;
};
/* opcode allocated if it needs to store data for async defer */
void *async_data;
u8 opcode;
/* polled IO has completed */
u8 iopoll_completed;
u16 buf_index;
u32 result;
struct io_ring_ctx *ctx;
unsigned int flags;
refcount_t refs;
struct task_struct *task;
u64 user_data;
struct list_head link_list;
/*
* 1. used with ctx->iopoll_list with reads/writes
* 2. to track reqs with ->files (see io_op_def::file_table)
*/
struct list_head inflight_entry;
struct percpu_ref *fixed_file_refs;
struct callback_head task_work;
/* for polled requests, i.e. IORING_OP_POLL_ADD and async armed poll */
struct hlist_node hash_node;
struct async_poll *apoll;
struct io_wq_work work;
};
struct io_defer_entry {
struct list_head list;
struct io_kiocb *req;
u32 seq;
};
#define IO_IOPOLL_BATCH 8
struct io_comp_state {
unsigned int nr;
struct list_head list;
struct io_ring_ctx *ctx;
};
struct io_submit_state {
struct blk_plug plug;
/*
* io_kiocb alloc cache
*/
void *reqs[IO_IOPOLL_BATCH];
unsigned int free_reqs;
/*
* Batch completion logic
*/
struct io_comp_state comp;
/*
* File reference cache
*/
struct file *file;
unsigned int fd;
unsigned int has_refs;
unsigned int ios_left;
};
struct io_op_def {
/* needs req->file assigned */
unsigned needs_file : 1;
/* don't fail if file grab fails */
unsigned needs_file_no_error : 1;
/* hash wq insertion if file is a regular file */
unsigned hash_reg_file : 1;
/* unbound wq insertion if file is a non-regular file */
unsigned unbound_nonreg_file : 1;
/* opcode is not supported by this kernel */
unsigned not_supported : 1;
/* set if opcode supports polled "wait" */
unsigned pollin : 1;
unsigned pollout : 1;
/* op supports buffer selection */
unsigned buffer_select : 1;
/* must always have async data allocated */
unsigned needs_async_data : 1;
/* size of async data needed, if any */
unsigned short async_size;
unsigned work_flags;
};
static const struct io_op_def io_op_defs[] = {
[IORING_OP_NOP] = {},
[IORING_OP_READV] = {
.needs_file = 1,
.unbound_nonreg_file = 1,
.pollin = 1,
.buffer_select = 1,
.needs_async_data = 1,
.async_size = sizeof(struct io_async_rw),
.work_flags = IO_WQ_WORK_MM | IO_WQ_WORK_BLKCG,
},
[IORING_OP_WRITEV] = {
.needs_file = 1,
.hash_reg_file = 1,
.unbound_nonreg_file = 1,
.pollout = 1,
.needs_async_data = 1,
.async_size = sizeof(struct io_async_rw),
.work_flags = IO_WQ_WORK_MM | IO_WQ_WORK_BLKCG |
IO_WQ_WORK_FSIZE,
},
[IORING_OP_FSYNC] = {
.needs_file = 1,
.work_flags = IO_WQ_WORK_BLKCG,
},
[IORING_OP_READ_FIXED] = {
.needs_file = 1,
.unbound_nonreg_file = 1,
.pollin = 1,
.async_size = sizeof(struct io_async_rw),
.work_flags = IO_WQ_WORK_BLKCG | IO_WQ_WORK_MM,
},
[IORING_OP_WRITE_FIXED] = {
.needs_file = 1,
.hash_reg_file = 1,
.unbound_nonreg_file = 1,
.pollout = 1,
.async_size = sizeof(struct io_async_rw),
.work_flags = IO_WQ_WORK_BLKCG | IO_WQ_WORK_FSIZE |
IO_WQ_WORK_MM,
},
[IORING_OP_POLL_ADD] = {
.needs_file = 1,
.unbound_nonreg_file = 1,
},
[IORING_OP_POLL_REMOVE] = {},
[IORING_OP_SYNC_FILE_RANGE] = {
.needs_file = 1,
.work_flags = IO_WQ_WORK_BLKCG,
},
[IORING_OP_SENDMSG] = {
.needs_file = 1,
.unbound_nonreg_file = 1,
.pollout = 1,
.needs_async_data = 1,
.async_size = sizeof(struct io_async_msghdr),
.work_flags = IO_WQ_WORK_MM | IO_WQ_WORK_BLKCG |
IO_WQ_WORK_FS,
},
[IORING_OP_RECVMSG] = {
.needs_file = 1,
.unbound_nonreg_file = 1,
.pollin = 1,
.buffer_select = 1,
.needs_async_data = 1,
.async_size = sizeof(struct io_async_msghdr),
.work_flags = IO_WQ_WORK_MM | IO_WQ_WORK_BLKCG |
IO_WQ_WORK_FS,
},
[IORING_OP_TIMEOUT] = {
.needs_async_data = 1,
.async_size = sizeof(struct io_timeout_data),
.work_flags = IO_WQ_WORK_MM,
},
[IORING_OP_TIMEOUT_REMOVE] = {},
[IORING_OP_ACCEPT] = {
.needs_file = 1,
.unbound_nonreg_file = 1,
.pollin = 1,
.work_flags = IO_WQ_WORK_MM | IO_WQ_WORK_FILES,
},
[IORING_OP_ASYNC_CANCEL] = {},
[IORING_OP_LINK_TIMEOUT] = {
.needs_async_data = 1,
.async_size = sizeof(struct io_timeout_data),
.work_flags = IO_WQ_WORK_MM,
},
[IORING_OP_CONNECT] = {
.needs_file = 1,
.unbound_nonreg_file = 1,
.pollout = 1,
.needs_async_data = 1,
.async_size = sizeof(struct io_async_connect),
.work_flags = IO_WQ_WORK_MM,
},
[IORING_OP_FALLOCATE] = {
.needs_file = 1,
.work_flags = IO_WQ_WORK_BLKCG | IO_WQ_WORK_FSIZE,
},
[IORING_OP_OPENAT] = {
.work_flags = IO_WQ_WORK_FILES | IO_WQ_WORK_BLKCG |
IO_WQ_WORK_FS,
},
[IORING_OP_CLOSE] = {
.needs_file = 1,
.needs_file_no_error = 1,
.work_flags = IO_WQ_WORK_FILES | IO_WQ_WORK_BLKCG,
},
[IORING_OP_FILES_UPDATE] = {
.work_flags = IO_WQ_WORK_FILES | IO_WQ_WORK_MM,
},
[IORING_OP_STATX] = {
.work_flags = IO_WQ_WORK_FILES | IO_WQ_WORK_MM |
IO_WQ_WORK_FS | IO_WQ_WORK_BLKCG,
},
[IORING_OP_READ] = {
.needs_file = 1,
.unbound_nonreg_file = 1,
.pollin = 1,
.buffer_select = 1,
.async_size = sizeof(struct io_async_rw),
.work_flags = IO_WQ_WORK_MM | IO_WQ_WORK_BLKCG,
},
[IORING_OP_WRITE] = {
.needs_file = 1,
.unbound_nonreg_file = 1,
.pollout = 1,
.async_size = sizeof(struct io_async_rw),
.work_flags = IO_WQ_WORK_MM | IO_WQ_WORK_BLKCG |
IO_WQ_WORK_FSIZE,
},
[IORING_OP_FADVISE] = {
.needs_file = 1,
.work_flags = IO_WQ_WORK_BLKCG,
},
[IORING_OP_MADVISE] = {
.work_flags = IO_WQ_WORK_MM | IO_WQ_WORK_BLKCG,
},
[IORING_OP_SEND] = {
.needs_file = 1,
.unbound_nonreg_file = 1,
.pollout = 1,
.work_flags = IO_WQ_WORK_MM | IO_WQ_WORK_BLKCG,
},
[IORING_OP_RECV] = {
.needs_file = 1,
.unbound_nonreg_file = 1,
.pollin = 1,
.buffer_select = 1,
.work_flags = IO_WQ_WORK_MM | IO_WQ_WORK_BLKCG,
},
[IORING_OP_OPENAT2] = {
.work_flags = IO_WQ_WORK_FILES | IO_WQ_WORK_FS |
IO_WQ_WORK_BLKCG,
},
[IORING_OP_EPOLL_CTL] = {
.unbound_nonreg_file = 1,
.work_flags = IO_WQ_WORK_FILES,
},
[IORING_OP_SPLICE] = {
.needs_file = 1,
.hash_reg_file = 1,
.unbound_nonreg_file = 1,
.work_flags = IO_WQ_WORK_BLKCG,
},
[IORING_OP_PROVIDE_BUFFERS] = {},
[IORING_OP_REMOVE_BUFFERS] = {},
[IORING_OP_TEE] = {
.needs_file = 1,
.hash_reg_file = 1,
.unbound_nonreg_file = 1,
},
};
enum io_mem_account {
ACCT_LOCKED,
ACCT_PINNED,
};
static void __io_complete_rw(struct io_kiocb *req, long res, long res2,
struct io_comp_state *cs);
static void io_cqring_fill_event(struct io_kiocb *req, long res);
static void io_put_req(struct io_kiocb *req);
static void io_put_req_deferred(struct io_kiocb *req, int nr);
static void io_double_put_req(struct io_kiocb *req);
static struct io_kiocb *io_prep_linked_timeout(struct io_kiocb *req);
static void __io_queue_linked_timeout(struct io_kiocb *req);
static void io_queue_linked_timeout(struct io_kiocb *req);
static int __io_sqe_files_update(struct io_ring_ctx *ctx,
struct io_uring_files_update *ip,
unsigned nr_args);
static void __io_clean_op(struct io_kiocb *req);
static struct file *io_file_get(struct io_submit_state *state,
struct io_kiocb *req, int fd, bool fixed);
static void __io_queue_sqe(struct io_kiocb *req, struct io_comp_state *cs);
static void io_file_put_work(struct work_struct *work);
static ssize_t io_import_iovec(int rw, struct io_kiocb *req,
struct iovec **iovec, struct iov_iter *iter,
bool needs_lock);
static int io_setup_async_rw(struct io_kiocb *req, const struct iovec *iovec,
const struct iovec *fast_iov,
struct iov_iter *iter, bool force);
static struct kmem_cache *req_cachep;
static const struct file_operations io_uring_fops;
struct sock *io_uring_get_socket(struct file *file)
{
#if defined(CONFIG_UNIX)
if (file->f_op == &io_uring_fops) {
struct io_ring_ctx *ctx = file->private_data;
return ctx->ring_sock->sk;
}
#endif
return NULL;
}
EXPORT_SYMBOL(io_uring_get_socket);
static inline void io_clean_op(struct io_kiocb *req)
{
if (req->flags & (REQ_F_NEED_CLEANUP | REQ_F_BUFFER_SELECTED |
REQ_F_INFLIGHT))
__io_clean_op(req);
}
static void io_sq_thread_drop_mm(void)
{
struct mm_struct *mm = current->mm;
if (mm) {
kthread_unuse_mm(mm);
mmput(mm);
current->mm = NULL;
}
}
static int __io_sq_thread_acquire_mm(struct io_ring_ctx *ctx)
{
struct mm_struct *mm;
if (current->mm)
return 0;
/* Should never happen */
if (unlikely(!(ctx->flags & IORING_SETUP_SQPOLL)))
return -EFAULT;
task_lock(ctx->sqo_task);
mm = ctx->sqo_task->mm;
if (unlikely(!mm || !mmget_not_zero(mm)))
mm = NULL;
task_unlock(ctx->sqo_task);
if (mm) {
kthread_use_mm(mm);
return 0;
}
return -EFAULT;
}
static int io_sq_thread_acquire_mm(struct io_ring_ctx *ctx,
struct io_kiocb *req)
{
if (!(io_op_defs[req->opcode].work_flags & IO_WQ_WORK_MM))
return 0;
return __io_sq_thread_acquire_mm(ctx);
}
static void io_sq_thread_associate_blkcg(struct io_ring_ctx *ctx,
struct cgroup_subsys_state **cur_css)
{
#ifdef CONFIG_BLK_CGROUP
/* puts the old one when swapping */
if (*cur_css != ctx->sqo_blkcg_css) {
kthread_associate_blkcg(ctx->sqo_blkcg_css);
*cur_css = ctx->sqo_blkcg_css;
}
#endif
}
static void io_sq_thread_unassociate_blkcg(void)
{
#ifdef CONFIG_BLK_CGROUP
kthread_associate_blkcg(NULL);
#endif
}
static inline void req_set_fail_links(struct io_kiocb *req)
{
if ((req->flags & (REQ_F_LINK | REQ_F_HARDLINK)) == REQ_F_LINK)
req->flags |= REQ_F_FAIL_LINK;
}
/*
* None of these are dereferenced, they are simply used to check if any of
* them have changed. If we're under current and check they are still the
* same, we're fine to grab references to them for actual out-of-line use.
*/
static void io_init_identity(struct io_identity *id)
{
id->files = current->files;
id->mm = current->mm;
#ifdef CONFIG_BLK_CGROUP
rcu_read_lock();
id->blkcg_css = blkcg_css();
rcu_read_unlock();
#endif
id->creds = current_cred();
id->nsproxy = current->nsproxy;
id->fs = current->fs;
id->fsize = rlimit(RLIMIT_FSIZE);
#ifdef CONFIG_AUDIT
id->loginuid = current->loginuid;
id->sessionid = current->sessionid;
#endif
refcount_set(&id->count, 1);
}
static inline void __io_req_init_async(struct io_kiocb *req)
{
memset(&req->work, 0, sizeof(req->work));
req->flags |= REQ_F_WORK_INITIALIZED;
}
/*
* Note: must call io_req_init_async() for the first time you
* touch any members of io_wq_work.
*/
static inline void io_req_init_async(struct io_kiocb *req)
{
struct io_uring_task *tctx = current->io_uring;
if (req->flags & REQ_F_WORK_INITIALIZED)
return;
__io_req_init_async(req);
/* Grab a ref if this isn't our static identity */
req->work.identity = tctx->identity;
if (tctx->identity != &tctx->__identity)
refcount_inc(&req->work.identity->count);
}
static inline bool io_async_submit(struct io_ring_ctx *ctx)
{
return ctx->flags & IORING_SETUP_SQPOLL;
}
static void io_ring_ctx_ref_free(struct percpu_ref *ref)
{
struct io_ring_ctx *ctx = container_of(ref, struct io_ring_ctx, refs);
complete(&ctx->ref_comp);
}
static inline bool io_is_timeout_noseq(struct io_kiocb *req)
{
return !req->timeout.off;
}
static struct io_ring_ctx *io_ring_ctx_alloc(struct io_uring_params *p)
{
struct io_ring_ctx *ctx;
int hash_bits;
ctx = kzalloc(sizeof(*ctx), GFP_KERNEL);
if (!ctx)
return NULL;
ctx->fallback_req = kmem_cache_alloc(req_cachep, GFP_KERNEL);
if (!ctx->fallback_req)
goto err;
/*
* Use 5 bits less than the max cq entries, that should give us around
* 32 entries per hash list if totally full and uniformly spread.
*/
hash_bits = ilog2(p->cq_entries);
hash_bits -= 5;
if (hash_bits <= 0)
hash_bits = 1;
ctx->cancel_hash_bits = hash_bits;
ctx->cancel_hash = kmalloc((1U << hash_bits) * sizeof(struct hlist_head),
GFP_KERNEL);
if (!ctx->cancel_hash)
goto err;
__hash_init(ctx->cancel_hash, 1U << hash_bits);
if (percpu_ref_init(&ctx->refs, io_ring_ctx_ref_free,
PERCPU_REF_ALLOW_REINIT, GFP_KERNEL))
goto err;
ctx->flags = p->flags;
init_waitqueue_head(&ctx->sqo_sq_wait);
INIT_LIST_HEAD(&ctx->sqd_list);
init_waitqueue_head(&ctx->cq_wait);
INIT_LIST_HEAD(&ctx->cq_overflow_list);
init_completion(&ctx->ref_comp);
init_completion(&ctx->sq_thread_comp);
idr_init(&ctx->io_buffer_idr);
idr_init(&ctx->personality_idr);
mutex_init(&ctx->uring_lock);
init_waitqueue_head(&ctx->wait);
spin_lock_init(&ctx->completion_lock);
INIT_LIST_HEAD(&ctx->iopoll_list);
INIT_LIST_HEAD(&ctx->defer_list);
INIT_LIST_HEAD(&ctx->timeout_list);
init_waitqueue_head(&ctx->inflight_wait);
spin_lock_init(&ctx->inflight_lock);
INIT_LIST_HEAD(&ctx->inflight_list);
INIT_DELAYED_WORK(&ctx->file_put_work, io_file_put_work);
init_llist_head(&ctx->file_put_llist);
return ctx;
err:
if (ctx->fallback_req)
kmem_cache_free(req_cachep, ctx->fallback_req);
kfree(ctx->cancel_hash);
kfree(ctx);
return NULL;
}
static bool req_need_defer(struct io_kiocb *req, u32 seq)
{
if (unlikely(req->flags & REQ_F_IO_DRAIN)) {
struct io_ring_ctx *ctx = req->ctx;
return seq != ctx->cached_cq_tail
+ READ_ONCE(ctx->cached_cq_overflow);
}
return false;
}
static void __io_commit_cqring(struct io_ring_ctx *ctx)
{
struct io_rings *rings = ctx->rings;
/* order cqe stores with ring update */
smp_store_release(&rings->cq.tail, ctx->cached_cq_tail);
if (wq_has_sleeper(&ctx->cq_wait)) {
wake_up_interruptible(&ctx->cq_wait);
kill_fasync(&ctx->cq_fasync, SIGIO, POLL_IN);
}
}
static void io_put_identity(struct io_uring_task *tctx, struct io_kiocb *req)
{
if (req->work.identity == &tctx->__identity)
return;
if (refcount_dec_and_test(&req->work.identity->count))
kfree(req->work.identity);
}
static void io_req_clean_work(struct io_kiocb *req)
{
if (!(req->flags & REQ_F_WORK_INITIALIZED))
return;
req->flags &= ~REQ_F_WORK_INITIALIZED;
if (req->work.flags & IO_WQ_WORK_MM) {
mmdrop(req->work.identity->mm);
req->work.flags &= ~IO_WQ_WORK_MM;
}
#ifdef CONFIG_BLK_CGROUP
if (req->work.flags & IO_WQ_WORK_BLKCG) {
css_put(req->work.identity->blkcg_css);
req->work.flags &= ~IO_WQ_WORK_BLKCG;
}
#endif
if (req->work.flags & IO_WQ_WORK_CREDS) {
put_cred(req->work.identity->creds);
req->work.flags &= ~IO_WQ_WORK_CREDS;
}
if (req->work.flags & IO_WQ_WORK_FS) {
struct fs_struct *fs = req->work.identity->fs;
spin_lock(&req->work.identity->fs->lock);
if (--fs->users)
fs = NULL;
spin_unlock(&req->work.identity->fs->lock);
if (fs)
free_fs_struct(fs);
req->work.flags &= ~IO_WQ_WORK_FS;
}
io_put_identity(req->task->io_uring, req);
}
/*
* Create a private copy of io_identity, since some fields don't match
* the current context.
*/
static bool io_identity_cow(struct io_kiocb *req)
{
struct io_uring_task *tctx = current->io_uring;
const struct cred *creds = NULL;
struct io_identity *id;
if (req->work.flags & IO_WQ_WORK_CREDS)
creds = req->work.identity->creds;
id = kmemdup(req->work.identity, sizeof(*id), GFP_KERNEL);
if (unlikely(!id)) {
req->work.flags |= IO_WQ_WORK_CANCEL;
return false;
}
/*
* We can safely just re-init the creds we copied Either the field
* matches the current one, or we haven't grabbed it yet. The only
* exception is ->creds, through registered personalities, so handle
* that one separately.
*/
io_init_identity(id);
if (creds)
id->creds = creds;
/* add one for this request */
refcount_inc(&id->count);
/* drop tctx and req identity references, if needed */
if (tctx->identity != &tctx->__identity &&
refcount_dec_and_test(&tctx->identity->count))
kfree(tctx->identity);
if (req->work.identity != &tctx->__identity &&
refcount_dec_and_test(&req->work.identity->count))
kfree(req->work.identity);
req->work.identity = id;
tctx->identity = id;
return true;
}
static bool io_grab_identity(struct io_kiocb *req)
{
const struct io_op_def *def = &io_op_defs[req->opcode];
struct io_identity *id = req->work.identity;
struct io_ring_ctx *ctx = req->ctx;
if (def->work_flags & IO_WQ_WORK_FSIZE) {
if (id->fsize != rlimit(RLIMIT_FSIZE))
return false;
req->work.flags |= IO_WQ_WORK_FSIZE;
}
#ifdef CONFIG_BLK_CGROUP
if (!(req->work.flags & IO_WQ_WORK_BLKCG) &&
(def->work_flags & IO_WQ_WORK_BLKCG)) {
rcu_read_lock();
if (id->blkcg_css != blkcg_css()) {
rcu_read_unlock();
return false;
}
/*
* This should be rare, either the cgroup is dying or the task
* is moving cgroups. Just punt to root for the handful of ios.
*/
if (css_tryget_online(id->blkcg_css))
req->work.flags |= IO_WQ_WORK_BLKCG;
rcu_read_unlock();
}
#endif
if (!(req->work.flags & IO_WQ_WORK_CREDS)) {
if (id->creds != current_cred())
return false;
get_cred(id->creds);
req->work.flags |= IO_WQ_WORK_CREDS;
}
#ifdef CONFIG_AUDIT
if (!uid_eq(current->loginuid, id->loginuid) ||
current->sessionid != id->sessionid)
return false;
#endif
if (!(req->work.flags & IO_WQ_WORK_FS) &&
(def->work_flags & IO_WQ_WORK_FS)) {
if (current->fs != id->fs)
return false;
spin_lock(&id->fs->lock);
if (!id->fs->in_exec) {
id->fs->users++;
req->work.flags |= IO_WQ_WORK_FS;
} else {
req->work.flags |= IO_WQ_WORK_CANCEL;
}
spin_unlock(&current->fs->lock);
}
if (!(req->work.flags & IO_WQ_WORK_FILES) &&
(def->work_flags & IO_WQ_WORK_FILES) &&
!(req->flags & REQ_F_NO_FILE_TABLE)) {
if (id->files != current->files ||
id->nsproxy != current->nsproxy)
return false;
atomic_inc(&id->files->count);
get_nsproxy(id->nsproxy);
req->flags |= REQ_F_INFLIGHT;
spin_lock_irq(&ctx->inflight_lock);
list_add(&req->inflight_entry, &ctx->inflight_list);
spin_unlock_irq(&ctx->inflight_lock);
req->work.flags |= IO_WQ_WORK_FILES;
}
return true;
}
static void io_prep_async_work(struct io_kiocb *req)
{
const struct io_op_def *def = &io_op_defs[req->opcode];
struct io_ring_ctx *ctx = req->ctx;
struct io_identity *id;
io_req_init_async(req);
id = req->work.identity;
if (req->flags & REQ_F_FORCE_ASYNC)
req->work.flags |= IO_WQ_WORK_CONCURRENT;
if (req->flags & REQ_F_ISREG) {
if (def->hash_reg_file || (ctx->flags & IORING_SETUP_IOPOLL))
io_wq_hash_work(&req->work, file_inode(req->file));
} else {
if (def->unbound_nonreg_file)
req->work.flags |= IO_WQ_WORK_UNBOUND;
}
/* ->mm can never change on us */
if (!(req->work.flags & IO_WQ_WORK_MM) &&
(def->work_flags & IO_WQ_WORK_MM)) {
mmgrab(id->mm);
req->work.flags |= IO_WQ_WORK_MM;
}
/* if we fail grabbing identity, we must COW, regrab, and retry */
if (io_grab_identity(req))
return;
if (!io_identity_cow(req))
return;
/* can't fail at this point */
if (!io_grab_identity(req))
WARN_ON(1);
}
static void io_prep_async_link(struct io_kiocb *req)
{
struct io_kiocb *cur;
io_prep_async_work(req);
if (req->flags & REQ_F_LINK_HEAD)
list_for_each_entry(cur, &req->link_list, link_list)
io_prep_async_work(cur);
}
static struct io_kiocb *__io_queue_async_work(struct io_kiocb *req)
{
struct io_ring_ctx *ctx = req->ctx;
struct io_kiocb *link = io_prep_linked_timeout(req);
trace_io_uring_queue_async_work(ctx, io_wq_is_hashed(&req->work), req,
&req->work, req->flags);
io_wq_enqueue(ctx->io_wq, &req->work);
return link;
}
static void io_queue_async_work(struct io_kiocb *req)
{
struct io_kiocb *link;
/* init ->work of the whole link before punting */
io_prep_async_link(req);
link = __io_queue_async_work(req);
if (link)
io_queue_linked_timeout(link);
}
static void io_kill_timeout(struct io_kiocb *req)
{
struct io_timeout_data *io = req->async_data;
int ret;
ret = hrtimer_try_to_cancel(&io->timer);
if (ret != -1) {
atomic_set(&req->ctx->cq_timeouts,
atomic_read(&req->ctx->cq_timeouts) + 1);
list_del_init(&req->timeout.list);
io_cqring_fill_event(req, 0);
io_put_req_deferred(req, 1);
}
}
static bool io_task_match(struct io_kiocb *req, struct task_struct *tsk)
{
struct io_ring_ctx *ctx = req->ctx;
if (!tsk || req->task == tsk)
return true;
if (ctx->flags & IORING_SETUP_SQPOLL) {
if (ctx->sq_data && req->task == ctx->sq_data->thread)
return true;
}
return false;
}
/*
* Returns true if we found and killed one or more timeouts
*/
static bool io_kill_timeouts(struct io_ring_ctx *ctx, struct task_struct *tsk)
{
struct io_kiocb *req, *tmp;
int canceled = 0;
spin_lock_irq(&ctx->completion_lock);
list_for_each_entry_safe(req, tmp, &ctx->timeout_list, timeout.list) {
if (io_task_match(req, tsk)) {
io_kill_timeout(req);
canceled++;
}
}
spin_unlock_irq(&ctx->completion_lock);
return canceled != 0;
}
static void __io_queue_deferred(struct io_ring_ctx *ctx)
{
do {
struct io_defer_entry *de = list_first_entry(&ctx->defer_list,
struct io_defer_entry, list);
struct io_kiocb *link;
if (req_need_defer(de->req, de->seq))
break;
list_del_init(&de->list);
/* punt-init is done before queueing for defer */
link = __io_queue_async_work(de->req);
if (link) {
__io_queue_linked_timeout(link);
/* drop submission reference */
io_put_req_deferred(link, 1);
}
kfree(de);
} while (!list_empty(&ctx->defer_list));
}
static void io_flush_timeouts(struct io_ring_ctx *ctx)
{
while (!list_empty(&ctx->timeout_list)) {
struct io_kiocb *req = list_first_entry(&ctx->timeout_list,
struct io_kiocb, timeout.list);
if (io_is_timeout_noseq(req))
break;
if (req->timeout.target_seq != ctx->cached_cq_tail
- atomic_read(&ctx->cq_timeouts))
break;
list_del_init(&req->timeout.list);
io_kill_timeout(req);
}
}
static void io_commit_cqring(struct io_ring_ctx *ctx)
{
io_flush_timeouts(ctx);
__io_commit_cqring(ctx);
if (unlikely(!list_empty(&ctx->defer_list)))
__io_queue_deferred(ctx);
}
static inline bool io_sqring_full(struct io_ring_ctx *ctx)
{
struct io_rings *r = ctx->rings;
return READ_ONCE(r->sq.tail) - ctx->cached_sq_head == r->sq_ring_entries;
}
static struct io_uring_cqe *io_get_cqring(struct io_ring_ctx *ctx)
{
struct io_rings *rings = ctx->rings;
unsigned tail;
tail = ctx->cached_cq_tail;
/*
* writes to the cq entry need to come after reading head; the
* control dependency is enough as we're using WRITE_ONCE to
* fill the cq entry
*/
if (tail - READ_ONCE(rings->cq.head) == rings->cq_ring_entries)
return NULL;
ctx->cached_cq_tail++;
return &rings->cqes[tail & ctx->cq_mask];
}
static inline bool io_should_trigger_evfd(struct io_ring_ctx *ctx)
{
if (!ctx->cq_ev_fd)
return false;
if (READ_ONCE(ctx->rings->cq_flags) & IORING_CQ_EVENTFD_DISABLED)
return false;
if (!ctx->eventfd_async)
return true;
return io_wq_current_is_worker();
}
static void io_cqring_ev_posted(struct io_ring_ctx *ctx)
{
if (waitqueue_active(&ctx->wait))
wake_up(&ctx->wait);
if (ctx->sq_data && waitqueue_active(&ctx->sq_data->wait))
wake_up(&ctx->sq_data->wait);
if (io_should_trigger_evfd(ctx))
eventfd_signal(ctx->cq_ev_fd, 1);
}
static void io_cqring_mark_overflow(struct io_ring_ctx *ctx)
{
if (list_empty(&ctx->cq_overflow_list)) {
clear_bit(0, &ctx->sq_check_overflow);
clear_bit(0, &ctx->cq_check_overflow);
ctx->rings->sq_flags &= ~IORING_SQ_CQ_OVERFLOW;
}
}
static inline bool __io_match_files(struct io_kiocb *req,
struct files_struct *files)
{
return ((req->flags & REQ_F_WORK_INITIALIZED) &&
(req->work.flags & IO_WQ_WORK_FILES)) &&
req->work.identity->files == files;
}
static bool io_match_files(struct io_kiocb *req,
struct files_struct *files)
{
struct io_kiocb *link;
if (!files)
return true;
if (__io_match_files(req, files))
return true;
if (req->flags & REQ_F_LINK_HEAD) {
list_for_each_entry(link, &req->link_list, link_list) {
if (__io_match_files(link, files))
return true;
}
}
return false;
}
/* Returns true if there are no backlogged entries after the flush */
static bool io_cqring_overflow_flush(struct io_ring_ctx *ctx, bool force,
struct task_struct *tsk,
struct files_struct *files)
{
struct io_rings *rings = ctx->rings;
struct io_kiocb *req, *tmp;
struct io_uring_cqe *cqe;
unsigned long flags;
LIST_HEAD(list);
if (!force) {
if (list_empty_careful(&ctx->cq_overflow_list))
return true;
if ((ctx->cached_cq_tail - READ_ONCE(rings->cq.head) ==
rings->cq_ring_entries))
return false;
}
spin_lock_irqsave(&ctx->completion_lock, flags);
/* if force is set, the ring is going away. always drop after that */
if (force)
ctx->cq_overflow_flushed = 1;
cqe = NULL;
list_for_each_entry_safe(req, tmp, &ctx->cq_overflow_list, compl.list) {
if (tsk && req->task != tsk)
continue;
if (!io_match_files(req, files))
continue;
cqe = io_get_cqring(ctx);
if (!cqe && !force)
break;
list_move(&req->compl.list, &list);
if (cqe) {
WRITE_ONCE(cqe->user_data, req->user_data);
WRITE_ONCE(cqe->res, req->result);
WRITE_ONCE(cqe->flags, req->compl.cflags);
} else {
ctx->cached_cq_overflow++;
WRITE_ONCE(ctx->rings->cq_overflow,
ctx->cached_cq_overflow);
}
}
io_commit_cqring(ctx);
io_cqring_mark_overflow(ctx);
spin_unlock_irqrestore(&ctx->completion_lock, flags);
io_cqring_ev_posted(ctx);
while (!list_empty(&list)) {
req = list_first_entry(&list, struct io_kiocb, compl.list);
list_del(&req->compl.list);
io_put_req(req);
}
return cqe != NULL;
}
static void __io_cqring_fill_event(struct io_kiocb *req, long res, long cflags)
{
struct io_ring_ctx *ctx = req->ctx;
struct io_uring_cqe *cqe;
trace_io_uring_complete(ctx, req->user_data, res);
/*
* If we can't get a cq entry, userspace overflowed the
* submission (by quite a lot). Increment the overflow count in
* the ring.
*/
cqe = io_get_cqring(ctx);
if (likely(cqe)) {
WRITE_ONCE(cqe->user_data, req->user_data);
WRITE_ONCE(cqe->res, res);
WRITE_ONCE(cqe->flags, cflags);
} else if (ctx->cq_overflow_flushed ||
atomic_read(&req->task->io_uring->in_idle)) {
/*
* If we're in ring overflow flush mode, or in task cancel mode,
* then we cannot store the request for later flushing, we need
* to drop it on the floor.
*/
ctx->cached_cq_overflow++;
WRITE_ONCE(ctx->rings->cq_overflow, ctx->cached_cq_overflow);
} else {
if (list_empty(&ctx->cq_overflow_list)) {
set_bit(0, &ctx->sq_check_overflow);
set_bit(0, &ctx->cq_check_overflow);
ctx->rings->sq_flags |= IORING_SQ_CQ_OVERFLOW;
}
io_clean_op(req);
req->result = res;
req->compl.cflags = cflags;
refcount_inc(&req->refs);
list_add_tail(&req->compl.list, &ctx->cq_overflow_list);
}
}
static void io_cqring_fill_event(struct io_kiocb *req, long res)
{
__io_cqring_fill_event(req, res, 0);
}
static void io_cqring_add_event(struct io_kiocb *req, long res, long cflags)
{
struct io_ring_ctx *ctx = req->ctx;
unsigned long flags;
spin_lock_irqsave(&ctx->completion_lock, flags);
__io_cqring_fill_event(req, res, cflags);
io_commit_cqring(ctx);
spin_unlock_irqrestore(&ctx->completion_lock, flags);
io_cqring_ev_posted(ctx);
}
static void io_submit_flush_completions(struct io_comp_state *cs)
{
struct io_ring_ctx *ctx = cs->ctx;
spin_lock_irq(&ctx->completion_lock);
while (!list_empty(&cs->list)) {
struct io_kiocb *req;
req = list_first_entry(&cs->list, struct io_kiocb, compl.list);
list_del(&req->compl.list);
__io_cqring_fill_event(req, req->result, req->compl.cflags);
/*
* io_free_req() doesn't care about completion_lock unless one
* of these flags is set. REQ_F_WORK_INITIALIZED is in the list
* because of a potential deadlock with req->work.fs->lock
*/
if (req->flags & (REQ_F_FAIL_LINK|REQ_F_LINK_TIMEOUT
|REQ_F_WORK_INITIALIZED)) {
spin_unlock_irq(&ctx->completion_lock);
io_put_req(req);
spin_lock_irq(&ctx->completion_lock);
} else {
io_put_req(req);
}
}
io_commit_cqring(ctx);
spin_unlock_irq(&ctx->completion_lock);
io_cqring_ev_posted(ctx);
cs->nr = 0;
}
static void __io_req_complete(struct io_kiocb *req, long res, unsigned cflags,
struct io_comp_state *cs)
{
if (!cs) {
io_cqring_add_event(req, res, cflags);
io_put_req(req);
} else {
io_clean_op(req);
req->result = res;
req->compl.cflags = cflags;
list_add_tail(&req->compl.list, &cs->list);
if (++cs->nr >= 32)
io_submit_flush_completions(cs);
}
}
static void io_req_complete(struct io_kiocb *req, long res)
{
__io_req_complete(req, res, 0, NULL);
}
static inline bool io_is_fallback_req(struct io_kiocb *req)
{
return req == (struct io_kiocb *)
((unsigned long) req->ctx->fallback_req & ~1UL);
}
static struct io_kiocb *io_get_fallback_req(struct io_ring_ctx *ctx)
{
struct io_kiocb *req;
req = ctx->fallback_req;
if (!test_and_set_bit_lock(0, (unsigned long *) &ctx->fallback_req))
return req;
return NULL;
}
static struct io_kiocb *io_alloc_req(struct io_ring_ctx *ctx,
struct io_submit_state *state)
{
if (!state->free_reqs) {
gfp_t gfp = GFP_KERNEL | __GFP_NOWARN;
size_t sz;
int ret;
sz = min_t(size_t, state->ios_left, ARRAY_SIZE(state->reqs));
ret = kmem_cache_alloc_bulk(req_cachep, gfp, sz, state->reqs);
/*
* Bulk alloc is all-or-nothing. If we fail to get a batch,
* retry single alloc to be on the safe side.
*/
if (unlikely(ret <= 0)) {
state->reqs[0] = kmem_cache_alloc(req_cachep, gfp);
if (!state->reqs[0])
goto fallback;
ret = 1;
}
state->free_reqs = ret;
}
state->free_reqs--;
return state->reqs[state->free_reqs];
fallback:
return io_get_fallback_req(ctx);
}
static inline void io_put_file(struct io_kiocb *req, struct file *file,
bool fixed)
{
if (fixed)
percpu_ref_put(req->fixed_file_refs);
else
fput(file);
}
static void io_dismantle_req(struct io_kiocb *req)
{
io_clean_op(req);
if (req->async_data)
kfree(req->async_data);
if (req->file)
io_put_file(req, req->file, (req->flags & REQ_F_FIXED_FILE));
io_req_clean_work(req);
}
static void __io_free_req(struct io_kiocb *req)
{
struct io_uring_task *tctx = req->task->io_uring;
struct io_ring_ctx *ctx = req->ctx;
io_dismantle_req(req);
percpu_counter_dec(&tctx->inflight);
if (atomic_read(&tctx->in_idle))
wake_up(&tctx->wait);
put_task_struct(req->task);
if (likely(!io_is_fallback_req(req)))
kmem_cache_free(req_cachep, req);
else
clear_bit_unlock(0, (unsigned long *) &ctx->fallback_req);
percpu_ref_put(&ctx->refs);
}
static void io_kill_linked_timeout(struct io_kiocb *req)
{
struct io_ring_ctx *ctx = req->ctx;
struct io_kiocb *link;
bool cancelled = false;
unsigned long flags;
spin_lock_irqsave(&ctx->completion_lock, flags);
link = list_first_entry_or_null(&req->link_list, struct io_kiocb,
link_list);
/*
* Can happen if a linked timeout fired and link had been like
* req -> link t-out -> link t-out [-> ...]
*/
if (link && (link->flags & REQ_F_LTIMEOUT_ACTIVE)) {
struct io_timeout_data *io = link->async_data;
int ret;
list_del_init(&link->link_list);
ret = hrtimer_try_to_cancel(&io->timer);
if (ret != -1) {
io_cqring_fill_event(link, -ECANCELED);
io_commit_cqring(ctx);
cancelled = true;
}
}
req->flags &= ~REQ_F_LINK_TIMEOUT;
spin_unlock_irqrestore(&ctx->completion_lock, flags);
if (cancelled) {
io_cqring_ev_posted(ctx);
io_put_req(link);
}
}
static struct io_kiocb *io_req_link_next(struct io_kiocb *req)
{
struct io_kiocb *nxt;
/*
* The list should never be empty when we are called here. But could
* potentially happen if the chain is messed up, check to be on the
* safe side.
*/
if (unlikely(list_empty(&req->link_list)))
return NULL;
nxt = list_first_entry(&req->link_list, struct io_kiocb, link_list);
list_del_init(&req->link_list);
if (!list_empty(&nxt->link_list))
nxt->flags |= REQ_F_LINK_HEAD;
return nxt;
}
/*
* Called if REQ_F_LINK_HEAD is set, and we fail the head request
*/
static void io_fail_links(struct io_kiocb *req)
{
struct io_ring_ctx *ctx = req->ctx;
unsigned long flags;
spin_lock_irqsave(&ctx->completion_lock, flags);
while (!list_empty(&req->link_list)) {
struct io_kiocb *link = list_first_entry(&req->link_list,
struct io_kiocb, link_list);
list_del_init(&link->link_list);
trace_io_uring_fail_link(req, link);
io_cqring_fill_event(link, -ECANCELED);
/*
* It's ok to free under spinlock as they're not linked anymore,
* but avoid REQ_F_WORK_INITIALIZED because it may deadlock on
* work.fs->lock.
*/
if (link->flags & REQ_F_WORK_INITIALIZED)
io_put_req_deferred(link, 2);
else
io_double_put_req(link);
}
io_commit_cqring(ctx);
spin_unlock_irqrestore(&ctx->completion_lock, flags);
io_cqring_ev_posted(ctx);
}
static struct io_kiocb *__io_req_find_next(struct io_kiocb *req)
{
req->flags &= ~REQ_F_LINK_HEAD;
if (req->flags & REQ_F_LINK_TIMEOUT)
io_kill_linked_timeout(req);
/*
* If LINK is set, we have dependent requests in this chain. If we
* didn't fail this request, queue the first one up, moving any other
* dependencies to the next request. In case of failure, fail the rest
* of the chain.
*/
if (likely(!(req->flags & REQ_F_FAIL_LINK)))
return io_req_link_next(req);
io_fail_links(req);
return NULL;
}
static struct io_kiocb *io_req_find_next(struct io_kiocb *req)
{
if (likely(!(req->flags & REQ_F_LINK_HEAD)))
return NULL;
return __io_req_find_next(req);
}
static int io_req_task_work_add(struct io_kiocb *req, bool twa_signal_ok)
{
struct task_struct *tsk = req->task;
struct io_ring_ctx *ctx = req->ctx;
enum task_work_notify_mode notify;
int ret;
if (tsk->flags & PF_EXITING)
return -ESRCH;
/*
* SQPOLL kernel thread doesn't need notification, just a wakeup. For
* all other cases, use TWA_SIGNAL unconditionally to ensure we're
* processing task_work. There's no reliable way to tell if TWA_RESUME
* will do the job.
*/
notify = TWA_NONE;
if (!(ctx->flags & IORING_SETUP_SQPOLL) && twa_signal_ok)
notify = TWA_SIGNAL;
ret = task_work_add(tsk, &req->task_work, notify);
if (!ret)
wake_up_process(tsk);
return ret;
}
static void __io_req_task_cancel(struct io_kiocb *req, int error)
{
struct io_ring_ctx *ctx = req->ctx;
spin_lock_irq(&ctx->completion_lock);
io_cqring_fill_event(req, error);
io_commit_cqring(ctx);
spin_unlock_irq(&ctx->completion_lock);
io_cqring_ev_posted(ctx);
req_set_fail_links(req);
io_double_put_req(req);
}
static void io_req_task_cancel(struct callback_head *cb)
{
struct io_kiocb *req = container_of(cb, struct io_kiocb, task_work);
struct io_ring_ctx *ctx = req->ctx;
__io_req_task_cancel(req, -ECANCELED);
percpu_ref_put(&ctx->refs);
}
static void __io_req_task_submit(struct io_kiocb *req)
{
struct io_ring_ctx *ctx = req->ctx;
if (!__io_sq_thread_acquire_mm(ctx)) {
mutex_lock(&ctx->uring_lock);
__io_queue_sqe(req, NULL);
mutex_unlock(&ctx->uring_lock);
} else {
__io_req_task_cancel(req, -EFAULT);
}
}
static void io_req_task_submit(struct callback_head *cb)
{
struct io_kiocb *req = container_of(cb, struct io_kiocb, task_work);
struct io_ring_ctx *ctx = req->ctx;
__io_req_task_submit(req);
percpu_ref_put(&ctx->refs);
}
static void io_req_task_queue(struct io_kiocb *req)
{
int ret;
init_task_work(&req->task_work, io_req_task_submit);
percpu_ref_get(&req->ctx->refs);
ret = io_req_task_work_add(req, true);
if (unlikely(ret)) {
struct task_struct *tsk;
init_task_work(&req->task_work, io_req_task_cancel);
tsk = io_wq_get_task(req->ctx->io_wq);
task_work_add(tsk, &req->task_work, TWA_NONE);
wake_up_process(tsk);
}
}
static void io_queue_next(struct io_kiocb *req)
{
struct io_kiocb *nxt = io_req_find_next(req);
if (nxt)
io_req_task_queue(nxt);
}
static void io_free_req(struct io_kiocb *req)
{
io_queue_next(req);
__io_free_req(req);
}
struct req_batch {
void *reqs[IO_IOPOLL_BATCH];
int to_free;
struct task_struct *task;
int task_refs;
};
static inline void io_init_req_batch(struct req_batch *rb)
{
rb->to_free = 0;
rb->task_refs = 0;
rb->task = NULL;
}
static void __io_req_free_batch_flush(struct io_ring_ctx *ctx,
struct req_batch *rb)
{
kmem_cache_free_bulk(req_cachep, rb->to_free, rb->reqs);
percpu_ref_put_many(&ctx->refs, rb->to_free);
rb->to_free = 0;
}
static void io_req_free_batch_finish(struct io_ring_ctx *ctx,
struct req_batch *rb)
{
if (rb->to_free)
__io_req_free_batch_flush(ctx, rb);
if (rb->task) {
struct io_uring_task *tctx = rb->task->io_uring;
percpu_counter_sub(&tctx->inflight, rb->task_refs);
put_task_struct_many(rb->task, rb->task_refs);
rb->task = NULL;
}
}
static void io_req_free_batch(struct req_batch *rb, struct io_kiocb *req)
{
if (unlikely(io_is_fallback_req(req))) {
io_free_req(req);
return;
}
if (req->flags & REQ_F_LINK_HEAD)
io_queue_next(req);
if (req->task != rb->task) {
if (rb->task) {
struct io_uring_task *tctx = rb->task->io_uring;
percpu_counter_sub(&tctx->inflight, rb->task_refs);
put_task_struct_many(rb->task, rb->task_refs);
}
rb->task = req->task;
rb->task_refs = 0;
}
rb->task_refs++;
io_dismantle_req(req);
rb->reqs[rb->to_free++] = req;
if (unlikely(rb->to_free == ARRAY_SIZE(rb->reqs)))
__io_req_free_batch_flush(req->ctx, rb);
}
/*
* Drop reference to request, return next in chain (if there is one) if this
* was the last reference to this request.
*/
static struct io_kiocb *io_put_req_find_next(struct io_kiocb *req)
{
struct io_kiocb *nxt = NULL;
if (refcount_dec_and_test(&req->refs)) {
nxt = io_req_find_next(req);
__io_free_req(req);
}
return nxt;
}
static void io_put_req(struct io_kiocb *req)
{
if (refcount_dec_and_test(&req->refs))
io_free_req(req);
}
static void io_put_req_deferred_cb(struct callback_head *cb)
{
struct io_kiocb *req = container_of(cb, struct io_kiocb, task_work);
io_free_req(req);
}
static void io_free_req_deferred(struct io_kiocb *req)
{
int ret;
init_task_work(&req->task_work, io_put_req_deferred_cb);
ret = io_req_task_work_add(req, true);
if (unlikely(ret)) {
struct task_struct *tsk;
tsk = io_wq_get_task(req->ctx->io_wq);
task_work_add(tsk, &req->task_work, TWA_NONE);
wake_up_process(tsk);
}
}
static inline void io_put_req_deferred(struct io_kiocb *req, int refs)
{
if (refcount_sub_and_test(refs, &req->refs))
io_free_req_deferred(req);
}
static struct io_wq_work *io_steal_work(struct io_kiocb *req)
{
struct io_kiocb *nxt;
/*
* A ref is owned by io-wq in which context we're. So, if that's the
* last one, it's safe to steal next work. False negatives are Ok,
* it just will be re-punted async in io_put_work()
*/
if (refcount_read(&req->refs) != 1)
return NULL;
nxt = io_req_find_next(req);
return nxt ? &nxt->work : NULL;
}
static void io_double_put_req(struct io_kiocb *req)
{
/* drop both submit and complete references */
if (refcount_sub_and_test(2, &req->refs))
io_free_req(req);
}
static unsigned io_cqring_events(struct io_ring_ctx *ctx, bool noflush)
{
struct io_rings *rings = ctx->rings;
if (test_bit(0, &ctx->cq_check_overflow)) {
/*
* noflush == true is from the waitqueue handler, just ensure
* we wake up the task, and the next invocation will flush the
* entries. We cannot safely to it from here.
*/
if (noflush && !list_empty(&ctx->cq_overflow_list))
return -1U;
io_cqring_overflow_flush(ctx, false, NULL, NULL);
}
/* See comment at the top of this file */
smp_rmb();
return ctx->cached_cq_tail - READ_ONCE(rings->cq.head);
}
static inline unsigned int io_sqring_entries(struct io_ring_ctx *ctx)
{
struct io_rings *rings = ctx->rings;
/* make sure SQ entry isn't read before tail */
return smp_load_acquire(&rings->sq.tail) - ctx->cached_sq_head;
}
static unsigned int io_put_kbuf(struct io_kiocb *req, struct io_buffer *kbuf)
{
unsigned int cflags;
cflags = kbuf->bid << IORING_CQE_BUFFER_SHIFT;
cflags |= IORING_CQE_F_BUFFER;
req->flags &= ~REQ_F_BUFFER_SELECTED;
kfree(kbuf);
return cflags;
}
static inline unsigned int io_put_rw_kbuf(struct io_kiocb *req)
{
struct io_buffer *kbuf;
kbuf = (struct io_buffer *) (unsigned long) req->rw.addr;
return io_put_kbuf(req, kbuf);
}
static inline bool io_run_task_work(void)
{
/*
* Not safe to run on exiting task, and the task_work handling will
* not add work to such a task.
*/
if (unlikely(current->flags & PF_EXITING))
return false;
if (current->task_works) {
__set_current_state(TASK_RUNNING);
task_work_run();
return true;
}
return false;
}
static void io_iopoll_queue(struct list_head *again)
{
struct io_kiocb *req;
do {
req = list_first_entry(again, struct io_kiocb, inflight_entry);
list_del(&req->inflight_entry);
__io_complete_rw(req, -EAGAIN, 0, NULL);
} while (!list_empty(again));
}
/*
* Find and free completed poll iocbs
*/
static void io_iopoll_complete(struct io_ring_ctx *ctx, unsigned int *nr_events,
struct list_head *done)
{
struct req_batch rb;
struct io_kiocb *req;
LIST_HEAD(again);
/* order with ->result store in io_complete_rw_iopoll() */
smp_rmb();
io_init_req_batch(&rb);
while (!list_empty(done)) {
int cflags = 0;
req = list_first_entry(done, struct io_kiocb, inflight_entry);
if (READ_ONCE(req->result) == -EAGAIN) {
req->result = 0;
req->iopoll_completed = 0;
list_move_tail(&req->inflight_entry, &again);
continue;
}
list_del(&req->inflight_entry);
if (req->flags & REQ_F_BUFFER_SELECTED)
cflags = io_put_rw_kbuf(req);
__io_cqring_fill_event(req, req->result, cflags);
(*nr_events)++;
if (refcount_dec_and_test(&req->refs))
io_req_free_batch(&rb, req);
}
io_commit_cqring(ctx);
if (ctx->flags & IORING_SETUP_SQPOLL)
io_cqring_ev_posted(ctx);
io_req_free_batch_finish(ctx, &rb);
if (!list_empty(&again))
io_iopoll_queue(&again);
}
static int io_do_iopoll(struct io_ring_ctx *ctx, unsigned int *nr_events,
long min)
{
struct io_kiocb *req, *tmp;
LIST_HEAD(done);
bool spin;
int ret;
/*
* Only spin for completions if we don't have multiple devices hanging
* off our complete list, and we're under the requested amount.
*/
spin = !ctx->poll_multi_file && *nr_events < min;
ret = 0;
list_for_each_entry_safe(req, tmp, &ctx->iopoll_list, inflight_entry) {
struct kiocb *kiocb = &req->rw.kiocb;
/*
* Move completed and retryable entries to our local lists.
* If we find a request that requires polling, break out
* and complete those lists first, if we have entries there.
*/
if (READ_ONCE(req->iopoll_completed)) {
list_move_tail(&req->inflight_entry, &done);
continue;
}
if (!list_empty(&done))
break;
ret = kiocb->ki_filp->f_op->iopoll(kiocb, spin);
if (ret < 0)
break;
/* iopoll may have completed current req */
if (READ_ONCE(req->iopoll_completed))
list_move_tail(&req->inflight_entry, &done);
if (ret && spin)
spin = false;
ret = 0;
}
if (!list_empty(&done))
io_iopoll_complete(ctx, nr_events, &done);
return ret;
}
/*
* Poll for a minimum of 'min' events. Note that if min == 0 we consider that a
* non-spinning poll check - we'll still enter the driver poll loop, but only
* as a non-spinning completion check.
*/
static int io_iopoll_getevents(struct io_ring_ctx *ctx, unsigned int *nr_events,
long min)
{
while (!list_empty(&ctx->iopoll_list) && !need_resched()) {
int ret;
ret = io_do_iopoll(ctx, nr_events, min);
if (ret < 0)
return ret;
if (*nr_events >= min)
return 0;
}
return 1;
}
/*
* We can't just wait for polled events to come to us, we have to actively
* find and complete them.
*/
static void io_iopoll_try_reap_events(struct io_ring_ctx *ctx)
{
if (!(ctx->flags & IORING_SETUP_IOPOLL))
return;
mutex_lock(&ctx->uring_lock);
while (!list_empty(&ctx->iopoll_list)) {
unsigned int nr_events = 0;
io_do_iopoll(ctx, &nr_events, 0);
/* let it sleep and repeat later if can't complete a request */
if (nr_events == 0)
break;
/*
* Ensure we allow local-to-the-cpu processing to take place,
* in this case we need to ensure that we reap all events.
* Also let task_work, etc. to progress by releasing the mutex
*/
if (need_resched()) {
mutex_unlock(&ctx->uring_lock);
cond_resched();
mutex_lock(&ctx->uring_lock);
}
}
mutex_unlock(&ctx->uring_lock);
}
static int io_iopoll_check(struct io_ring_ctx *ctx, long min)
{
unsigned int nr_events = 0;
int iters = 0, ret = 0;
/*
* We disallow the app entering submit/complete with polling, but we
* still need to lock the ring to prevent racing with polled issue
* that got punted to a workqueue.
*/
mutex_lock(&ctx->uring_lock);
do {
/*
* Don't enter poll loop if we already have events pending.
* If we do, we can potentially be spinning for commands that
* already triggered a CQE (eg in error).
*/
if (io_cqring_events(ctx, false))
break;
/*
* If a submit got punted to a workqueue, we can have the
* application entering polling for a command before it gets
* issued. That app will hold the uring_lock for the duration
* of the poll right here, so we need to take a breather every
* now and then to ensure that the issue has a chance to add
* the poll to the issued list. Otherwise we can spin here
* forever, while the workqueue is stuck trying to acquire the
* very same mutex.
*/
if (!(++iters & 7)) {
mutex_unlock(&ctx->uring_lock);
io_run_task_work();
mutex_lock(&ctx->uring_lock);
}
ret = io_iopoll_getevents(ctx, &nr_events, min);
if (ret <= 0)
break;
ret = 0;
} while (min && !nr_events && !need_resched());
mutex_unlock(&ctx->uring_lock);
return ret;
}
static void kiocb_end_write(struct io_kiocb *req)
{
/*
* Tell lockdep we inherited freeze protection from submission
* thread.
*/
if (req->flags & REQ_F_ISREG) {
struct inode *inode = file_inode(req->file);
__sb_writers_acquired(inode->i_sb, SB_FREEZE_WRITE);
}
file_end_write(req->file);
}
static void io_complete_rw_common(struct kiocb *kiocb, long res,
struct io_comp_state *cs)
{
struct io_kiocb *req = container_of(kiocb, struct io_kiocb, rw.kiocb);
int cflags = 0;
if (kiocb->ki_flags & IOCB_WRITE)
kiocb_end_write(req);
if (res != req->result)
req_set_fail_links(req);
if (req->flags & REQ_F_BUFFER_SELECTED)
cflags = io_put_rw_kbuf(req);
__io_req_complete(req, res, cflags, cs);
}
#ifdef CONFIG_BLOCK
static bool io_resubmit_prep(struct io_kiocb *req, int error)
{
struct iovec inline_vecs[UIO_FASTIOV], *iovec = inline_vecs;
ssize_t ret = -ECANCELED;
struct iov_iter iter;
int rw;
if (error) {
ret = error;
goto end_req;
}
switch (req->opcode) {
case IORING_OP_READV:
case IORING_OP_READ_FIXED:
case IORING_OP_READ:
rw = READ;
break;
case IORING_OP_WRITEV:
case IORING_OP_WRITE_FIXED:
case IORING_OP_WRITE:
rw = WRITE;
break;
default:
printk_once(KERN_WARNING "io_uring: bad opcode in resubmit %d\n",
req->opcode);
goto end_req;
}
if (!req->async_data) {
ret = io_import_iovec(rw, req, &iovec, &iter, false);
if (ret < 0)
goto end_req;
ret = io_setup_async_rw(req, iovec, inline_vecs, &iter, false);
if (!ret)
return true;
kfree(iovec);
} else {
return true;
}
end_req:
req_set_fail_links(req);
return false;
}
#endif
static bool io_rw_reissue(struct io_kiocb *req, long res)
{
#ifdef CONFIG_BLOCK
umode_t mode = file_inode(req->file)->i_mode;
int ret;
if (!S_ISBLK(mode) && !S_ISREG(mode))
return false;
if ((res != -EAGAIN && res != -EOPNOTSUPP) || io_wq_current_is_worker())
return false;
ret = io_sq_thread_acquire_mm(req->ctx, req);
if (io_resubmit_prep(req, ret)) {
refcount_inc(&req->refs);
io_queue_async_work(req);
return true;
}
#endif
return false;
}
static void __io_complete_rw(struct io_kiocb *req, long res, long res2,
struct io_comp_state *cs)
{
if (!io_rw_reissue(req, res))
io_complete_rw_common(&req->rw.kiocb, res, cs);
}
static void io_complete_rw(struct kiocb *kiocb, long res, long res2)
{
struct io_kiocb *req = container_of(kiocb, struct io_kiocb, rw.kiocb);
__io_complete_rw(req, res, res2, NULL);
}
static void io_complete_rw_iopoll(struct kiocb *kiocb, long res, long res2)
{
struct io_kiocb *req = container_of(kiocb, struct io_kiocb, rw.kiocb);
if (kiocb->ki_flags & IOCB_WRITE)
kiocb_end_write(req);
if (res != -EAGAIN && res != req->result)
req_set_fail_links(req);
WRITE_ONCE(req->result, res);
/* order with io_poll_complete() checking ->result */
smp_wmb();
WRITE_ONCE(req->iopoll_completed, 1);
}
/*
* After the iocb has been issued, it's safe to be found on the poll list.
* Adding the kiocb to the list AFTER submission ensures that we don't
* find it from a io_iopoll_getevents() thread before the issuer is done
* accessing the kiocb cookie.
*/
static void io_iopoll_req_issued(struct io_kiocb *req)
{
struct io_ring_ctx *ctx = req->ctx;
/*
* Track whether we have multiple files in our lists. This will impact
* how we do polling eventually, not spinning if we're on potentially
* different devices.
*/
if (list_empty(&ctx->iopoll_list)) {
ctx->poll_multi_file = false;
} else if (!ctx->poll_multi_file) {
struct io_kiocb *list_req;
list_req = list_first_entry(&ctx->iopoll_list, struct io_kiocb,
inflight_entry);
if (list_req->file != req->file)
ctx->poll_multi_file = true;
}
/*
* For fast devices, IO may have already completed. If it has, add
* it to the front so we find it first.
*/
if (READ_ONCE(req->iopoll_completed))
list_add(&req->inflight_entry, &ctx->iopoll_list);
else
list_add_tail(&req->inflight_entry, &ctx->iopoll_list);
if ((ctx->flags & IORING_SETUP_SQPOLL) &&
wq_has_sleeper(&ctx->sq_data->wait))
wake_up(&ctx->sq_data->wait);
}
static void __io_state_file_put(struct io_submit_state *state)
{
if (state->has_refs)
fput_many(state->file, state->has_refs);
state->file = NULL;
}
static inline void io_state_file_put(struct io_submit_state *state)
{
if (state->file)
__io_state_file_put(state);
}
/*
* Get as many references to a file as we have IOs left in this submission,
* assuming most submissions are for one file, or at least that each file
* has more than one submission.
*/
static struct file *__io_file_get(struct io_submit_state *state, int fd)
{
if (!state)
return fget(fd);
if (state->file) {
if (state->fd == fd) {
state->has_refs--;
return state->file;
}
__io_state_file_put(state);
}
state->file = fget_many(fd, state->ios_left);
if (!state->file)
return NULL;
state->fd = fd;
state->has_refs = state->ios_left - 1;
return state->file;
}
static bool io_bdev_nowait(struct block_device *bdev)
{
#ifdef CONFIG_BLOCK
return !bdev || blk_queue_nowait(bdev_get_queue(bdev));
#else
return true;
#endif
}
/*
* If we tracked the file through the SCM inflight mechanism, we could support
* any file. For now, just ensure that anything potentially problematic is done
* inline.
*/
static bool io_file_supports_async(struct file *file, int rw)
{
umode_t mode = file_inode(file)->i_mode;
if (S_ISBLK(mode)) {
if (io_bdev_nowait(file->f_inode->i_bdev))
return true;
return false;
}
if (S_ISCHR(mode) || S_ISSOCK(mode))
return true;
if (S_ISREG(mode)) {
if (io_bdev_nowait(file->f_inode->i_sb->s_bdev) &&
file->f_op != &io_uring_fops)
return true;
return false;
}
/* any ->read/write should understand O_NONBLOCK */
if (file->f_flags & O_NONBLOCK)
return true;
if (!(file->f_mode & FMODE_NOWAIT))
return false;
if (rw == READ)
return file->f_op->read_iter != NULL;
return file->f_op->write_iter != NULL;
}
static int io_prep_rw(struct io_kiocb *req, const struct io_uring_sqe *sqe)
{
struct io_ring_ctx *ctx = req->ctx;
struct kiocb *kiocb = &req->rw.kiocb;
unsigned ioprio;
int ret;
if (S_ISREG(file_inode(req->file)->i_mode))
req->flags |= REQ_F_ISREG;
kiocb->ki_pos = READ_ONCE(sqe->off);
if (kiocb->ki_pos == -1 && !(req->file->f_mode & FMODE_STREAM)) {
req->flags |= REQ_F_CUR_POS;
kiocb->ki_pos = req->file->f_pos;
}
kiocb->ki_hint = ki_hint_validate(file_write_hint(kiocb->ki_filp));
kiocb->ki_flags = iocb_flags(kiocb->ki_filp);
ret = kiocb_set_rw_flags(kiocb, READ_ONCE(sqe->rw_flags));
if (unlikely(ret))
return ret;
ioprio = READ_ONCE(sqe->ioprio);
if (ioprio) {
ret = ioprio_check_cap(ioprio);
if (ret)
return ret;
kiocb->ki_ioprio = ioprio;
} else
kiocb->ki_ioprio = get_current_ioprio();
/* don't allow async punt if RWF_NOWAIT was requested */
if (kiocb->ki_flags & IOCB_NOWAIT)
req->flags |= REQ_F_NOWAIT;
if (ctx->flags & IORING_SETUP_IOPOLL) {
if (!(kiocb->ki_flags & IOCB_DIRECT) ||
!kiocb->ki_filp->f_op->iopoll)
return -EOPNOTSUPP;
kiocb->ki_flags |= IOCB_HIPRI;
kiocb->ki_complete = io_complete_rw_iopoll;
req->iopoll_completed = 0;
} else {
if (kiocb->ki_flags & IOCB_HIPRI)
return -EINVAL;
kiocb->ki_complete = io_complete_rw;
}
req->rw.addr = READ_ONCE(sqe->addr);
req->rw.len = READ_ONCE(sqe->len);
req->buf_index = READ_ONCE(sqe->buf_index);
return 0;
}
static inline void io_rw_done(struct kiocb *kiocb, ssize_t ret)
{
switch (ret) {
case -EIOCBQUEUED:
break;
case -ERESTARTSYS:
case -ERESTARTNOINTR:
case -ERESTARTNOHAND:
case -ERESTART_RESTARTBLOCK:
/*
* We can't just restart the syscall, since previously
* submitted sqes may already be in progress. Just fail this
* IO with EINTR.
*/
ret = -EINTR;
fallthrough;
default:
kiocb->ki_complete(kiocb, ret, 0);
}
}
static void kiocb_done(struct kiocb *kiocb, ssize_t ret,
struct io_comp_state *cs)
{
struct io_kiocb *req = container_of(kiocb, struct io_kiocb, rw.kiocb);
struct io_async_rw *io = req->async_data;
/* add previously done IO, if any */
if (io && io->bytes_done > 0) {
if (ret < 0)
ret = io->bytes_done;
else
ret += io->bytes_done;
}
if (req->flags & REQ_F_CUR_POS)
req->file->f_pos = kiocb->ki_pos;
if (ret >= 0 && kiocb->ki_complete == io_complete_rw)
__io_complete_rw(req, ret, 0, cs);
else
io_rw_done(kiocb, ret);
}
static ssize_t io_import_fixed(struct io_kiocb *req, int rw,
struct iov_iter *iter)
{
struct io_ring_ctx *ctx = req->ctx;
size_t len = req->rw.len;
struct io_mapped_ubuf *imu;
u16 index, buf_index = req->buf_index;
size_t offset;
u64 buf_addr;
if (unlikely(buf_index >= ctx->nr_user_bufs))
return -EFAULT;
index = array_index_nospec(buf_index, ctx->nr_user_bufs);
imu = &ctx->user_bufs[index];
buf_addr = req->rw.addr;
/* overflow */
if (buf_addr + len < buf_addr)
return -EFAULT;
/* not inside the mapped region */
if (buf_addr < imu->ubuf || buf_addr + len > imu->ubuf + imu->len)
return -EFAULT;
/*
* May not be a start of buffer, set size appropriately
* and advance us to the beginning.
*/
offset = buf_addr - imu->ubuf;
iov_iter_bvec(iter, rw, imu->bvec, imu->nr_bvecs, offset + len);
if (offset) {
/*
* Don't use iov_iter_advance() here, as it's really slow for
* using the latter parts of a big fixed buffer - it iterates
* over each segment manually. We can cheat a bit here, because
* we know that:
*
* 1) it's a BVEC iter, we set it up
* 2) all bvecs are PAGE_SIZE in size, except potentially the
* first and last bvec
*
* So just find our index, and adjust the iterator afterwards.
* If the offset is within the first bvec (or the whole first
* bvec, just use iov_iter_advance(). This makes it easier
* since we can just skip the first segment, which may not
* be PAGE_SIZE aligned.
*/
const struct bio_vec *bvec = imu->bvec;
if (offset <= bvec->bv_len) {
iov_iter_advance(iter, offset);
} else {
unsigned long seg_skip;
/* skip first vec */
offset -= bvec->bv_len;
seg_skip = 1 + (offset >> PAGE_SHIFT);
iter->bvec = bvec + seg_skip;
iter->nr_segs -= seg_skip;
iter->count -= bvec->bv_len + offset;
iter->iov_offset = offset & ~PAGE_MASK;
}
}
return len;
}
static void io_ring_submit_unlock(struct io_ring_ctx *ctx, bool needs_lock)
{
if (needs_lock)
mutex_unlock(&ctx->uring_lock);
}
static void io_ring_submit_lock(struct io_ring_ctx *ctx, bool needs_lock)
{
/*
* "Normal" inline submissions always hold the uring_lock, since we
* grab it from the system call. Same is true for the SQPOLL offload.
* The only exception is when we've detached the request and issue it
* from an async worker thread, grab the lock for that case.
*/
if (needs_lock)
mutex_lock(&ctx->uring_lock);
}
static struct io_buffer *io_buffer_select(struct io_kiocb *req, size_t *len,
int bgid, struct io_buffer *kbuf,
bool needs_lock)
{
struct io_buffer *head;
if (req->flags & REQ_F_BUFFER_SELECTED)
return kbuf;
io_ring_submit_lock(req->ctx, needs_lock);
lockdep_assert_held(&req->ctx->uring_lock);
head = idr_find(&req->ctx->io_buffer_idr, bgid);
if (head) {
if (!list_empty(&head->list)) {
kbuf = list_last_entry(&head->list, struct io_buffer,
list);
list_del(&kbuf->list);
} else {
kbuf = head;
idr_remove(&req->ctx->io_buffer_idr, bgid);
}
if (*len > kbuf->len)
*len = kbuf->len;
} else {
kbuf = ERR_PTR(-ENOBUFS);
}
io_ring_submit_unlock(req->ctx, needs_lock);
return kbuf;
}
static void __user *io_rw_buffer_select(struct io_kiocb *req, size_t *len,
bool needs_lock)
{
struct io_buffer *kbuf;
u16 bgid;
kbuf = (struct io_buffer *) (unsigned long) req->rw.addr;
bgid = req->buf_index;
kbuf = io_buffer_select(req, len, bgid, kbuf, needs_lock);
if (IS_ERR(kbuf))
return kbuf;
req->rw.addr = (u64) (unsigned long) kbuf;
req->flags |= REQ_F_BUFFER_SELECTED;
return u64_to_user_ptr(kbuf->addr);
}
#ifdef CONFIG_COMPAT
static ssize_t io_compat_import(struct io_kiocb *req, struct iovec *iov,
bool needs_lock)
{
struct compat_iovec __user *uiov;
compat_ssize_t clen;
void __user *buf;
ssize_t len;
uiov = u64_to_user_ptr(req->rw.addr);
if (!access_ok(uiov, sizeof(*uiov)))
return -EFAULT;
if (__get_user(clen, &uiov->iov_len))
return -EFAULT;
if (clen < 0)
return -EINVAL;
len = clen;
buf = io_rw_buffer_select(req, &len, needs_lock);
if (IS_ERR(buf))
return PTR_ERR(buf);
iov[0].iov_base = buf;
iov[0].iov_len = (compat_size_t) len;
return 0;
}
#endif
static ssize_t __io_iov_buffer_select(struct io_kiocb *req, struct iovec *iov,
bool needs_lock)
{
struct iovec __user *uiov = u64_to_user_ptr(req->rw.addr);
void __user *buf;
ssize_t len;
if (copy_from_user(iov, uiov, sizeof(*uiov)))
return -EFAULT;
len = iov[0].iov_len;
if (len < 0)
return -EINVAL;
buf = io_rw_buffer_select(req, &len, needs_lock);
if (IS_ERR(buf))
return PTR_ERR(buf);
iov[0].iov_base = buf;
iov[0].iov_len = len;
return 0;
}
static ssize_t io_iov_buffer_select(struct io_kiocb *req, struct iovec *iov,
bool needs_lock)
{
if (req->flags & REQ_F_BUFFER_SELECTED) {
struct io_buffer *kbuf;
kbuf = (struct io_buffer *) (unsigned long) req->rw.addr;
iov[0].iov_base = u64_to_user_ptr(kbuf->addr);
iov[0].iov_len = kbuf->len;
return 0;
}
if (!req->rw.len)
return 0;
else if (req->rw.len > 1)
return -EINVAL;
#ifdef CONFIG_COMPAT
if (req->ctx->compat)
return io_compat_import(req, iov, needs_lock);
#endif
return __io_iov_buffer_select(req, iov, needs_lock);
}
static ssize_t __io_import_iovec(int rw, struct io_kiocb *req,
struct iovec **iovec, struct iov_iter *iter,
bool needs_lock)
{
void __user *buf = u64_to_user_ptr(req->rw.addr);
size_t sqe_len = req->rw.len;
ssize_t ret;
u8 opcode;
opcode = req->opcode;
if (opcode == IORING_OP_READ_FIXED || opcode == IORING_OP_WRITE_FIXED) {
*iovec = NULL;
return io_import_fixed(req, rw, iter);
}
/* buffer index only valid with fixed read/write, or buffer select */
if (req->buf_index && !(req->flags & REQ_F_BUFFER_SELECT))
return -EINVAL;
if (opcode == IORING_OP_READ || opcode == IORING_OP_WRITE) {
if (req->flags & REQ_F_BUFFER_SELECT) {
buf = io_rw_buffer_select(req, &sqe_len, needs_lock);
if (IS_ERR(buf))
return PTR_ERR(buf);
req->rw.len = sqe_len;
}
ret = import_single_range(rw, buf, sqe_len, *iovec, iter);
*iovec = NULL;
return ret < 0 ? ret : sqe_len;
}
if (req->flags & REQ_F_BUFFER_SELECT) {
ret = io_iov_buffer_select(req, *iovec, needs_lock);
if (!ret) {
ret = (*iovec)->iov_len;
iov_iter_init(iter, rw, *iovec, 1, ret);
}
*iovec = NULL;
return ret;
}
return __import_iovec(rw, buf, sqe_len, UIO_FASTIOV, iovec, iter,
req->ctx->compat);
}
static ssize_t io_import_iovec(int rw, struct io_kiocb *req,
struct iovec **iovec, struct iov_iter *iter,
bool needs_lock)
{
struct io_async_rw *iorw = req->async_data;
if (!iorw)
return __io_import_iovec(rw, req, iovec, iter, needs_lock);
*iovec = NULL;
return iov_iter_count(&iorw->iter);
}
static inline loff_t *io_kiocb_ppos(struct kiocb *kiocb)
{
return (kiocb->ki_filp->f_mode & FMODE_STREAM) ? NULL : &kiocb->ki_pos;
}
/*
* For files that don't have ->read_iter() and ->write_iter(), handle them
* by looping over ->read() or ->write() manually.
*/
static ssize_t loop_rw_iter(int rw, struct io_kiocb *req, struct iov_iter *iter)
{
struct kiocb *kiocb = &req->rw.kiocb;
struct file *file = req->file;
ssize_t ret = 0;
/*
* Don't support polled IO through this interface, and we can't
* support non-blocking either. For the latter, this just causes
* the kiocb to be handled from an async context.
*/
if (kiocb->ki_flags & IOCB_HIPRI)
return -EOPNOTSUPP;
if (kiocb->ki_flags & IOCB_NOWAIT)
return -EAGAIN;
while (iov_iter_count(iter)) {
struct iovec iovec;
ssize_t nr;
if (!iov_iter_is_bvec(iter)) {
iovec = iov_iter_iovec(iter);
} else {
iovec.iov_base = u64_to_user_ptr(req->rw.addr);
iovec.iov_len = req->rw.len;
}
if (rw == READ) {
nr = file->f_op->read(file, iovec.iov_base,
iovec.iov_len, io_kiocb_ppos(kiocb));
} else {
nr = file->f_op->write(file, iovec.iov_base,
iovec.iov_len, io_kiocb_ppos(kiocb));
}
if (nr < 0) {
if (!ret)
ret = nr;
break;
}
ret += nr;
if (nr != iovec.iov_len)
break;
req->rw.len -= nr;
req->rw.addr += nr;
iov_iter_advance(iter, nr);
}
return ret;
}
static void io_req_map_rw(struct io_kiocb *req, const struct iovec *iovec,
const struct iovec *fast_iov, struct iov_iter *iter)
{
struct io_async_rw *rw = req->async_data;
memcpy(&rw->iter, iter, sizeof(*iter));
rw->free_iovec = iovec;
rw->bytes_done = 0;
/* can only be fixed buffers, no need to do anything */
if (iov_iter_is_bvec(iter))
return;
if (!iovec) {
unsigned iov_off = 0;
rw->iter.iov = rw->fast_iov;
if (iter->iov != fast_iov) {
iov_off = iter->iov - fast_iov;
rw->iter.iov += iov_off;
}
if (rw->fast_iov != fast_iov)
memcpy(rw->fast_iov + iov_off, fast_iov + iov_off,
sizeof(struct iovec) * iter->nr_segs);
} else {
req->flags |= REQ_F_NEED_CLEANUP;
}
}
static inline int __io_alloc_async_data(struct io_kiocb *req)
{
WARN_ON_ONCE(!io_op_defs[req->opcode].async_size);
req->async_data = kmalloc(io_op_defs[req->opcode].async_size, GFP_KERNEL);
return req->async_data == NULL;
}
static int io_alloc_async_data(struct io_kiocb *req)
{
if (!io_op_defs[req->opcode].needs_async_data)
return 0;
return __io_alloc_async_data(req);
}
static int io_setup_async_rw(struct io_kiocb *req, const struct iovec *iovec,
const struct iovec *fast_iov,
struct iov_iter *iter, bool force)
{
if (!force && !io_op_defs[req->opcode].needs_async_data)
return 0;
if (!req->async_data) {
if (__io_alloc_async_data(req))
return -ENOMEM;
io_req_map_rw(req, iovec, fast_iov, iter);
}
return 0;
}
static inline int io_rw_prep_async(struct io_kiocb *req, int rw)
{
struct io_async_rw *iorw = req->async_data;
struct iovec *iov = iorw->fast_iov;
ssize_t ret;
ret = __io_import_iovec(rw, req, &iov, &iorw->iter, false);
if (unlikely(ret < 0))
return ret;
iorw->bytes_done = 0;
iorw->free_iovec = iov;
if (iov)
req->flags |= REQ_F_NEED_CLEANUP;
return 0;
}
static int io_read_prep(struct io_kiocb *req, const struct io_uring_sqe *sqe)
{
ssize_t ret;
ret = io_prep_rw(req, sqe);
if (ret)
return ret;
if (unlikely(!(req->file->f_mode & FMODE_READ)))
return -EBADF;
/* either don't need iovec imported or already have it */
if (!req->async_data)
return 0;
return io_rw_prep_async(req, READ);
}
/*
* This is our waitqueue callback handler, registered through lock_page_async()
* when we initially tried to do the IO with the iocb armed our waitqueue.
* This gets called when the page is unlocked, and we generally expect that to
* happen when the page IO is completed and the page is now uptodate. This will
* queue a task_work based retry of the operation, attempting to copy the data
* again. If the latter fails because the page was NOT uptodate, then we will
* do a thread based blocking retry of the operation. That's the unexpected
* slow path.
*/
static int io_async_buf_func(struct wait_queue_entry *wait, unsigned mode,
int sync, void *arg)
{
struct wait_page_queue *wpq;
struct io_kiocb *req = wait->private;
struct wait_page_key *key = arg;
int ret;
wpq = container_of(wait, struct wait_page_queue, wait);
if (!wake_page_match(wpq, key))
return 0;
req->rw.kiocb.ki_flags &= ~IOCB_WAITQ;
list_del_init(&wait->entry);
init_task_work(&req->task_work, io_req_task_submit);
percpu_ref_get(&req->ctx->refs);
/* submit ref gets dropped, acquire a new one */
refcount_inc(&req->refs);
ret = io_req_task_work_add(req, true);
if (unlikely(ret)) {
struct task_struct *tsk;
/* queue just for cancelation */
init_task_work(&req->task_work, io_req_task_cancel);
tsk = io_wq_get_task(req->ctx->io_wq);
task_work_add(tsk, &req->task_work, TWA_NONE);
wake_up_process(tsk);
}
return 1;
}
/*
* This controls whether a given IO request should be armed for async page
* based retry. If we return false here, the request is handed to the async
* worker threads for retry. If we're doing buffered reads on a regular file,
* we prepare a private wait_page_queue entry and retry the operation. This
* will either succeed because the page is now uptodate and unlocked, or it
* will register a callback when the page is unlocked at IO completion. Through
* that callback, io_uring uses task_work to setup a retry of the operation.
* That retry will attempt the buffered read again. The retry will generally
* succeed, or in rare cases where it fails, we then fall back to using the
* async worker threads for a blocking retry.
*/
static bool io_rw_should_retry(struct io_kiocb *req)
{
struct io_async_rw *rw = req->async_data;
struct wait_page_queue *wait = &rw->wpq;
struct kiocb *kiocb = &req->rw.kiocb;
/* never retry for NOWAIT, we just complete with -EAGAIN */
if (req->flags & REQ_F_NOWAIT)
return false;
/* Only for buffered IO */
if (kiocb->ki_flags & (IOCB_DIRECT | IOCB_HIPRI))
return false;
/*
* just use poll if we can, and don't attempt if the fs doesn't
* support callback based unlocks
*/
if (file_can_poll(req->file) || !(req->file->f_mode & FMODE_BUF_RASYNC))
return false;
wait->wait.func = io_async_buf_func;
wait->wait.private = req;
wait->wait.flags = 0;
INIT_LIST_HEAD(&wait->wait.entry);
kiocb->ki_flags |= IOCB_WAITQ;
kiocb->ki_flags &= ~IOCB_NOWAIT;
kiocb->ki_waitq = wait;
return true;
}
static int io_iter_do_read(struct io_kiocb *req, struct iov_iter *iter)
{
if (req->file->f_op->read_iter)
return call_read_iter(req->file, &req->rw.kiocb, iter);
else if (req->file->f_op->read)
return loop_rw_iter(READ, req, iter);
else
return -EINVAL;
}
static int io_read(struct io_kiocb *req, bool force_nonblock,
struct io_comp_state *cs)
{
struct iovec inline_vecs[UIO_FASTIOV], *iovec = inline_vecs;
struct kiocb *kiocb = &req->rw.kiocb;
struct iov_iter __iter, *iter = &__iter;
struct io_async_rw *rw = req->async_data;
ssize_t io_size, ret, ret2;
size_t iov_count;
bool no_async;
if (rw)
iter = &rw->iter;
ret = io_import_iovec(READ, req, &iovec, iter, !force_nonblock);
if (ret < 0)
return ret;
iov_count = iov_iter_count(iter);
io_size = ret;
req->result = io_size;
ret = 0;
/* Ensure we clear previously set non-block flag */
if (!force_nonblock)
kiocb->ki_flags &= ~IOCB_NOWAIT;
else
kiocb->ki_flags |= IOCB_NOWAIT;
/* If the file doesn't support async, just async punt */
no_async = force_nonblock && !io_file_supports_async(req->file, READ);
if (no_async)
goto copy_iov;
ret = rw_verify_area(READ, req->file, io_kiocb_ppos(kiocb), iov_count);
if (unlikely(ret))
goto out_free;
ret = io_iter_do_read(req, iter);
if (!ret) {
goto done;
} else if (ret == -EIOCBQUEUED) {
ret = 0;
goto out_free;
} else if (ret == -EAGAIN) {
/* IOPOLL retry should happen for io-wq threads */
if (!force_nonblock && !(req->ctx->flags & IORING_SETUP_IOPOLL))
goto done;
/* no retry on NONBLOCK marked file */
if (req->file->f_flags & O_NONBLOCK)
goto done;
/* some cases will consume bytes even on error returns */
iov_iter_revert(iter, iov_count - iov_iter_count(iter));
ret = 0;
goto copy_iov;
} else if (ret < 0) {
/* make sure -ERESTARTSYS -> -EINTR is done */
goto done;
}
/* read it all, or we did blocking attempt. no retry. */
if (!iov_iter_count(iter) || !force_nonblock ||
(req->file->f_flags & O_NONBLOCK))
goto done;
io_size -= ret;
copy_iov:
ret2 = io_setup_async_rw(req, iovec, inline_vecs, iter, true);
if (ret2) {
ret = ret2;
goto out_free;
}
if (no_async)
return -EAGAIN;
rw = req->async_data;
/* it's copied and will be cleaned with ->io */
iovec = NULL;
/* now use our persistent iterator, if we aren't already */
iter = &rw->iter;
retry:
rw->bytes_done += ret;
/* if we can retry, do so with the callbacks armed */
if (!io_rw_should_retry(req)) {
kiocb->ki_flags &= ~IOCB_WAITQ;
return -EAGAIN;
}
/*
* Now retry read with the IOCB_WAITQ parts set in the iocb. If we
* get -EIOCBQUEUED, then we'll get a notification when the desired
* page gets unlocked. We can also get a partial read here, and if we
* do, then just retry at the new offset.
*/
ret = io_iter_do_read(req, iter);
if (ret == -EIOCBQUEUED) {
ret = 0;
goto out_free;
} else if (ret > 0 && ret < io_size) {
/* we got some bytes, but not all. retry. */
goto retry;
}
done:
kiocb_done(kiocb, ret, cs);
ret = 0;
out_free:
/* it's reportedly faster than delegating the null check to kfree() */
if (iovec)
kfree(iovec);
return ret;
}
static int io_write_prep(struct io_kiocb *req, const struct io_uring_sqe *sqe)
{
ssize_t ret;
ret = io_prep_rw(req, sqe);
if (ret)
return ret;
if (unlikely(!(req->file->f_mode & FMODE_WRITE)))
return -EBADF;
/* either don't need iovec imported or already have it */
if (!req->async_data)
return 0;
return io_rw_prep_async(req, WRITE);
}
static int io_write(struct io_kiocb *req, bool force_nonblock,
struct io_comp_state *cs)
{
struct iovec inline_vecs[UIO_FASTIOV], *iovec = inline_vecs;
struct kiocb *kiocb = &req->rw.kiocb;
struct iov_iter __iter, *iter = &__iter;
struct io_async_rw *rw = req->async_data;
size_t iov_count;
ssize_t ret, ret2, io_size;
if (rw)
iter = &rw->iter;
ret = io_import_iovec(WRITE, req, &iovec, iter, !force_nonblock);
if (ret < 0)
return ret;
iov_count = iov_iter_count(iter);
io_size = ret;
req->result = io_size;
/* Ensure we clear previously set non-block flag */
if (!force_nonblock)
kiocb->ki_flags &= ~IOCB_NOWAIT;
else
kiocb->ki_flags |= IOCB_NOWAIT;
/* If the file doesn't support async, just async punt */
if (force_nonblock && !io_file_supports_async(req->file, WRITE))
goto copy_iov;
/* file path doesn't support NOWAIT for non-direct_IO */
if (force_nonblock && !(kiocb->ki_flags & IOCB_DIRECT) &&
(req->flags & REQ_F_ISREG))
goto copy_iov;
ret = rw_verify_area(WRITE, req->file, io_kiocb_ppos(kiocb), iov_count);
if (unlikely(ret))
goto out_free;
/*
* Open-code file_start_write here to grab freeze protection,
* which will be released by another thread in
* io_complete_rw(). Fool lockdep by telling it the lock got
* released so that it doesn't complain about the held lock when
* we return to userspace.
*/
if (req->flags & REQ_F_ISREG) {
sb_start_write(file_inode(req->file)->i_sb);
__sb_writers_release(file_inode(req->file)->i_sb,
SB_FREEZE_WRITE);
}
kiocb->ki_flags |= IOCB_WRITE;
if (req->file->f_op->write_iter)
ret2 = call_write_iter(req->file, kiocb, iter);
else if (req->file->f_op->write)
ret2 = loop_rw_iter(WRITE, req, iter);
else
ret2 = -EINVAL;
/*
* Raw bdev writes will return -EOPNOTSUPP for IOCB_NOWAIT. Just
* retry them without IOCB_NOWAIT.
*/
if (ret2 == -EOPNOTSUPP && (kiocb->ki_flags & IOCB_NOWAIT))
ret2 = -EAGAIN;
/* no retry on NONBLOCK marked file */
if (ret2 == -EAGAIN && (req->file->f_flags & O_NONBLOCK))
goto done;
if (!force_nonblock || ret2 != -EAGAIN) {
/* IOPOLL retry should happen for io-wq threads */
if ((req->ctx->flags & IORING_SETUP_IOPOLL) && ret2 == -EAGAIN)
goto copy_iov;
done:
kiocb_done(kiocb, ret2, cs);
} else {
copy_iov:
/* some cases will consume bytes even on error returns */
iov_iter_revert(iter, iov_count - iov_iter_count(iter));
ret = io_setup_async_rw(req, iovec, inline_vecs, iter, false);
if (!ret)
return -EAGAIN;
}
out_free:
/* it's reportedly faster than delegating the null check to kfree() */
if (iovec)
kfree(iovec);
return ret;
}
static int __io_splice_prep(struct io_kiocb *req,
const struct io_uring_sqe *sqe)
{
struct io_splice* sp = &req->splice;
unsigned int valid_flags = SPLICE_F_FD_IN_FIXED | SPLICE_F_ALL;
if (unlikely(req->ctx->flags & IORING_SETUP_IOPOLL))
return -EINVAL;
sp->file_in = NULL;
sp->len = READ_ONCE(sqe->len);
sp->flags = READ_ONCE(sqe->splice_flags);
if (unlikely(sp->flags & ~valid_flags))
return -EINVAL;
sp->file_in = io_file_get(NULL, req, READ_ONCE(sqe->splice_fd_in),
(sp->flags & SPLICE_F_FD_IN_FIXED));
if (!sp->file_in)
return -EBADF;
req->flags |= REQ_F_NEED_CLEANUP;
if (!S_ISREG(file_inode(sp->file_in)->i_mode)) {
/*
* Splice operation will be punted aync, and here need to
* modify io_wq_work.flags, so initialize io_wq_work firstly.
*/
io_req_init_async(req);
req->work.flags |= IO_WQ_WORK_UNBOUND;
}
return 0;
}
static int io_tee_prep(struct io_kiocb *req,
const struct io_uring_sqe *sqe)
{
if (READ_ONCE(sqe->splice_off_in) || READ_ONCE(sqe->off))
return -EINVAL;
return __io_splice_prep(req, sqe);
}
static int io_tee(struct io_kiocb *req, bool force_nonblock)
{
struct io_splice *sp = &req->splice;
struct file *in = sp->file_in;
struct file *out = sp->file_out;
unsigned int flags = sp->flags & ~SPLICE_F_FD_IN_FIXED;
long ret = 0;
if (force_nonblock)
return -EAGAIN;
if (sp->len)
ret = do_tee(in, out, sp->len, flags);
io_put_file(req, in, (sp->flags & SPLICE_F_FD_IN_FIXED));
req->flags &= ~REQ_F_NEED_CLEANUP;
if (ret != sp->len)
req_set_fail_links(req);
io_req_complete(req, ret);
return 0;
}
static int io_splice_prep(struct io_kiocb *req, const struct io_uring_sqe *sqe)
{
struct io_splice* sp = &req->splice;
sp->off_in = READ_ONCE(sqe->splice_off_in);
sp->off_out = READ_ONCE(sqe->off);
return __io_splice_prep(req, sqe);
}
static int io_splice(struct io_kiocb *req, bool force_nonblock)
{
struct io_splice *sp = &req->splice;
struct file *in = sp->file_in;
struct file *out = sp->file_out;
unsigned int flags = sp->flags & ~SPLICE_F_FD_IN_FIXED;
loff_t *poff_in, *poff_out;
long ret = 0;
if (force_nonblock)
return -EAGAIN;
poff_in = (sp->off_in == -1) ? NULL : &sp->off_in;
poff_out = (sp->off_out == -1) ? NULL : &sp->off_out;
if (sp->len)
ret = do_splice(in, poff_in, out, poff_out, sp->len, flags);
io_put_file(req, in, (sp->flags & SPLICE_F_FD_IN_FIXED));
req->flags &= ~REQ_F_NEED_CLEANUP;
if (ret != sp->len)
req_set_fail_links(req);
io_req_complete(req, ret);
return 0;
}
/*
* IORING_OP_NOP just posts a completion event, nothing else.
*/
static int io_nop(struct io_kiocb *req, struct io_comp_state *cs)
{
struct io_ring_ctx *ctx = req->ctx;
if (unlikely(ctx->flags & IORING_SETUP_IOPOLL))
return -EINVAL;
__io_req_complete(req, 0, 0, cs);
return 0;
}
static int io_prep_fsync(struct io_kiocb *req, const struct io_uring_sqe *sqe)
{
struct io_ring_ctx *ctx = req->ctx;
if (!req->file)
return -EBADF;
if (unlikely(ctx->flags & IORING_SETUP_IOPOLL))
return -EINVAL;
if (unlikely(sqe->addr || sqe->ioprio || sqe->buf_index))
return -EINVAL;
req->sync.flags = READ_ONCE(sqe->fsync_flags);
if (unlikely(req->sync.flags & ~IORING_FSYNC_DATASYNC))
return -EINVAL;
req->sync.off = READ_ONCE(sqe->off);
req->sync.len = READ_ONCE(sqe->len);
return 0;
}
static int io_fsync(struct io_kiocb *req, bool force_nonblock)
{
loff_t end = req->sync.off + req->sync.len;
int ret;
/* fsync always requires a blocking context */
if (force_nonblock)
return -EAGAIN;
ret = vfs_fsync_range(req->file, req->sync.off,
end > 0 ? end : LLONG_MAX,
req->sync.flags & IORING_FSYNC_DATASYNC);
if (ret < 0)
req_set_fail_links(req);
io_req_complete(req, ret);
return 0;
}
static int io_fallocate_prep(struct io_kiocb *req,
const struct io_uring_sqe *sqe)
{
if (sqe->ioprio || sqe->buf_index || sqe->rw_flags)
return -EINVAL;
if (unlikely(req->ctx->flags & IORING_SETUP_IOPOLL))
return -EINVAL;
req->sync.off = READ_ONCE(sqe->off);
req->sync.len = READ_ONCE(sqe->addr);
req->sync.mode = READ_ONCE(sqe->len);
return 0;
}
static int io_fallocate(struct io_kiocb *req, bool force_nonblock)
{
int ret;
/* fallocate always requiring blocking context */
if (force_nonblock)
return -EAGAIN;
ret = vfs_fallocate(req->file, req->sync.mode, req->sync.off,
req->sync.len);
if (ret < 0)
req_set_fail_links(req);
io_req_complete(req, ret);
return 0;
}
static int __io_openat_prep(struct io_kiocb *req, const struct io_uring_sqe *sqe)
{
const char __user *fname;
int ret;
if (unlikely(sqe->ioprio || sqe->buf_index))
return -EINVAL;
if (unlikely(req->flags & REQ_F_FIXED_FILE))
return -EBADF;
/* open.how should be already initialised */
if (!(req->open.how.flags & O_PATH) && force_o_largefile())
req->open.how.flags |= O_LARGEFILE;
req->open.dfd = READ_ONCE(sqe->fd);
fname = u64_to_user_ptr(READ_ONCE(sqe->addr));
req->open.filename = getname(fname);
if (IS_ERR(req->open.filename)) {
ret = PTR_ERR(req->open.filename);
req->open.filename = NULL;
return ret;
}
req->open.nofile = rlimit(RLIMIT_NOFILE);
req->open.ignore_nonblock = false;
req->flags |= REQ_F_NEED_CLEANUP;
return 0;
}
static int io_openat_prep(struct io_kiocb *req, const struct io_uring_sqe *sqe)
{
u64 flags, mode;
if (unlikely(req->ctx->flags & (IORING_SETUP_IOPOLL|IORING_SETUP_SQPOLL)))
return -EINVAL;
mode = READ_ONCE(sqe->len);
flags = READ_ONCE(sqe->open_flags);
req->open.how = build_open_how(flags, mode);
return __io_openat_prep(req, sqe);
}
static int io_openat2_prep(struct io_kiocb *req, const struct io_uring_sqe *sqe)
{
struct open_how __user *how;
size_t len;
int ret;
if (unlikely(req->ctx->flags & (IORING_SETUP_IOPOLL|IORING_SETUP_SQPOLL)))
return -EINVAL;
how = u64_to_user_ptr(READ_ONCE(sqe->addr2));
len = READ_ONCE(sqe->len);
if (len < OPEN_HOW_SIZE_VER0)
return -EINVAL;
ret = copy_struct_from_user(&req->open.how, sizeof(req->open.how), how,
len);
if (ret)
return ret;
return __io_openat_prep(req, sqe);
}
static int io_openat2(struct io_kiocb *req, bool force_nonblock)
{
struct open_flags op;
struct file *file;
int ret;
if (force_nonblock && !req->open.ignore_nonblock)
return -EAGAIN;
ret = build_open_flags(&req->open.how, &op);
if (ret)
goto err;
ret = __get_unused_fd_flags(req->open.how.flags, req->open.nofile);
if (ret < 0)
goto err;
file = do_filp_open(req->open.dfd, req->open.filename, &op);
if (IS_ERR(file)) {
put_unused_fd(ret);
ret = PTR_ERR(file);
/*
* A work-around to ensure that /proc/self works that way
* that it should - if we get -EOPNOTSUPP back, then assume
* that proc_self_get_link() failed us because we're in async
* context. We should be safe to retry this from the task
* itself with force_nonblock == false set, as it should not
* block on lookup. Would be nice to know this upfront and
* avoid the async dance, but doesn't seem feasible.
*/
if (ret == -EOPNOTSUPP && io_wq_current_is_worker()) {
req->open.ignore_nonblock = true;
refcount_inc(&req->refs);
io_req_task_queue(req);
return 0;
}
} else {
fsnotify_open(file);
fd_install(ret, file);
}
err:
putname(req->open.filename);
req->flags &= ~REQ_F_NEED_CLEANUP;
if (ret < 0)
req_set_fail_links(req);
io_req_complete(req, ret);
return 0;
}
static int io_openat(struct io_kiocb *req, bool force_nonblock)
{
return io_openat2(req, force_nonblock);
}
static int io_remove_buffers_prep(struct io_kiocb *req,
const struct io_uring_sqe *sqe)
{
struct io_provide_buf *p = &req->pbuf;
u64 tmp;
if (sqe->ioprio || sqe->rw_flags || sqe->addr || sqe->len || sqe->off)
return -EINVAL;
tmp = READ_ONCE(sqe->fd);
if (!tmp || tmp > USHRT_MAX)
return -EINVAL;
memset(p, 0, sizeof(*p));
p->nbufs = tmp;
p->bgid = READ_ONCE(sqe->buf_group);
return 0;
}
static int __io_remove_buffers(struct io_ring_ctx *ctx, struct io_buffer *buf,
int bgid, unsigned nbufs)
{
unsigned i = 0;
/* shouldn't happen */
if (!nbufs)
return 0;
/* the head kbuf is the list itself */
while (!list_empty(&buf->list)) {
struct io_buffer *nxt;
nxt = list_first_entry(&buf->list, struct io_buffer, list);
list_del(&nxt->list);
kfree(nxt);
if (++i == nbufs)
return i;
}
i++;
kfree(buf);
idr_remove(&ctx->io_buffer_idr, bgid);
return i;
}
static int io_remove_buffers(struct io_kiocb *req, bool force_nonblock,
struct io_comp_state *cs)
{
struct io_provide_buf *p = &req->pbuf;
struct io_ring_ctx *ctx = req->ctx;
struct io_buffer *head;
int ret = 0;
io_ring_submit_lock(ctx, !force_nonblock);
lockdep_assert_held(&ctx->uring_lock);
ret = -ENOENT;
head = idr_find(&ctx->io_buffer_idr, p->bgid);
if (head)
ret = __io_remove_buffers(ctx, head, p->bgid, p->nbufs);
io_ring_submit_lock(ctx, !force_nonblock);
if (ret < 0)
req_set_fail_links(req);
__io_req_complete(req, ret, 0, cs);
return 0;
}
static int io_provide_buffers_prep(struct io_kiocb *req,
const struct io_uring_sqe *sqe)
{
struct io_provide_buf *p = &req->pbuf;
u64 tmp;
if (sqe->ioprio || sqe->rw_flags)
return -EINVAL;
tmp = READ_ONCE(sqe->fd);
if (!tmp || tmp > USHRT_MAX)
return -E2BIG;
p->nbufs = tmp;
p->addr = READ_ONCE(sqe->addr);
p->len = READ_ONCE(sqe->len);
if (!access_ok(u64_to_user_ptr(p->addr), (p->len * p->nbufs)))
return -EFAULT;
p->bgid = READ_ONCE(sqe->buf_group);
tmp = READ_ONCE(sqe->off);
if (tmp > USHRT_MAX)
return -E2BIG;
p->bid = tmp;
return 0;
}
static int io_add_buffers(struct io_provide_buf *pbuf, struct io_buffer **head)
{
struct io_buffer *buf;
u64 addr = pbuf->addr;
int i, bid = pbuf->bid;
for (i = 0; i < pbuf->nbufs; i++) {
buf = kmalloc(sizeof(*buf), GFP_KERNEL);
if (!buf)
break;
buf->addr = addr;
buf->len = pbuf->len;
buf->bid = bid;
addr += pbuf->len;
bid++;
if (!*head) {
INIT_LIST_HEAD(&buf->list);
*head = buf;
} else {
list_add_tail(&buf->list, &(*head)->list);
}
}
return i ? i : -ENOMEM;
}
static int io_provide_buffers(struct io_kiocb *req, bool force_nonblock,
struct io_comp_state *cs)
{
struct io_provide_buf *p = &req->pbuf;
struct io_ring_ctx *ctx = req->ctx;
struct io_buffer *head, *list;
int ret = 0;
io_ring_submit_lock(ctx, !force_nonblock);
lockdep_assert_held(&ctx->uring_lock);
list = head = idr_find(&ctx->io_buffer_idr, p->bgid);
ret = io_add_buffers(p, &head);
if (ret < 0)
goto out;
if (!list) {
ret = idr_alloc(&ctx->io_buffer_idr, head, p->bgid, p->bgid + 1,
GFP_KERNEL);
if (ret < 0) {
__io_remove_buffers(ctx, head, p->bgid, -1U);
goto out;
}
}
out:
io_ring_submit_unlock(ctx, !force_nonblock);
if (ret < 0)
req_set_fail_links(req);
__io_req_complete(req, ret, 0, cs);
return 0;
}
static int io_epoll_ctl_prep(struct io_kiocb *req,
const struct io_uring_sqe *sqe)
{
#if defined(CONFIG_EPOLL)
if (sqe->ioprio || sqe->buf_index)
return -EINVAL;
if (unlikely(req->ctx->flags & (IORING_SETUP_IOPOLL | IORING_SETUP_SQPOLL)))
return -EINVAL;
req->epoll.epfd = READ_ONCE(sqe->fd);
req->epoll.op = READ_ONCE(sqe->len);
req->epoll.fd = READ_ONCE(sqe->off);
if (ep_op_has_event(req->epoll.op)) {
struct epoll_event __user *ev;
ev = u64_to_user_ptr(READ_ONCE(sqe->addr));
if (copy_from_user(&req->epoll.event, ev, sizeof(*ev)))
return -EFAULT;
}
return 0;
#else
return -EOPNOTSUPP;
#endif
}
static int io_epoll_ctl(struct io_kiocb *req, bool force_nonblock,
struct io_comp_state *cs)
{
#if defined(CONFIG_EPOLL)
struct io_epoll *ie = &req->epoll;
int ret;
ret = do_epoll_ctl(ie->epfd, ie->op, ie->fd, &ie->event, force_nonblock);
if (force_nonblock && ret == -EAGAIN)
return -EAGAIN;
if (ret < 0)
req_set_fail_links(req);
__io_req_complete(req, ret, 0, cs);
return 0;
#else
return -EOPNOTSUPP;
#endif
}
static int io_madvise_prep(struct io_kiocb *req, const struct io_uring_sqe *sqe)
{
#if defined(CONFIG_ADVISE_SYSCALLS) && defined(CONFIG_MMU)
if (sqe->ioprio || sqe->buf_index || sqe->off)
return -EINVAL;
if (unlikely(req->ctx->flags & IORING_SETUP_IOPOLL))
return -EINVAL;
req->madvise.addr = READ_ONCE(sqe->addr);
req->madvise.len = READ_ONCE(sqe->len);
req->madvise.advice = READ_ONCE(sqe->fadvise_advice);
return 0;
#else
return -EOPNOTSUPP;
#endif
}
static int io_madvise(struct io_kiocb *req, bool force_nonblock)
{
#if defined(CONFIG_ADVISE_SYSCALLS) && defined(CONFIG_MMU)
struct io_madvise *ma = &req->madvise;
int ret;
if (force_nonblock)
return -EAGAIN;
ret = do_madvise(current->mm, ma->addr, ma->len, ma->advice);
if (ret < 0)
req_set_fail_links(req);
io_req_complete(req, ret);
return 0;
#else
return -EOPNOTSUPP;
#endif
}
static int io_fadvise_prep(struct io_kiocb *req, const struct io_uring_sqe *sqe)
{
if (sqe->ioprio || sqe->buf_index || sqe->addr)
return -EINVAL;
if (unlikely(req->ctx->flags & IORING_SETUP_IOPOLL))
return -EINVAL;
req->fadvise.offset = READ_ONCE(sqe->off);
req->fadvise.len = READ_ONCE(sqe->len);
req->fadvise.advice = READ_ONCE(sqe->fadvise_advice);
return 0;
}
static int io_fadvise(struct io_kiocb *req, bool force_nonblock)
{
struct io_fadvise *fa = &req->fadvise;
int ret;
if (force_nonblock) {
switch (fa->advice) {
case POSIX_FADV_NORMAL:
case POSIX_FADV_RANDOM:
case POSIX_FADV_SEQUENTIAL:
break;
default:
return -EAGAIN;
}
}
ret = vfs_fadvise(req->file, fa->offset, fa->len, fa->advice);
if (ret < 0)
req_set_fail_links(req);
io_req_complete(req, ret);
return 0;
}
static int io_statx_prep(struct io_kiocb *req, const struct io_uring_sqe *sqe)
{
if (unlikely(req->ctx->flags & (IORING_SETUP_IOPOLL | IORING_SETUP_SQPOLL)))
return -EINVAL;
if (sqe->ioprio || sqe->buf_index)
return -EINVAL;
if (req->flags & REQ_F_FIXED_FILE)
return -EBADF;
req->statx.dfd = READ_ONCE(sqe->fd);
req->statx.mask = READ_ONCE(sqe->len);
req->statx.filename = u64_to_user_ptr(READ_ONCE(sqe->addr));
req->statx.buffer = u64_to_user_ptr(READ_ONCE(sqe->addr2));
req->statx.flags = READ_ONCE(sqe->statx_flags);
return 0;
}
static int io_statx(struct io_kiocb *req, bool force_nonblock)
{
struct io_statx *ctx = &req->statx;
int ret;
if (force_nonblock) {
/* only need file table for an actual valid fd */
if (ctx->dfd == -1 || ctx->dfd == AT_FDCWD)
req->flags |= REQ_F_NO_FILE_TABLE;
return -EAGAIN;
}
ret = do_statx(ctx->dfd, ctx->filename, ctx->flags, ctx->mask,
ctx->buffer);
if (ret < 0)
req_set_fail_links(req);
io_req_complete(req, ret);
return 0;
}
static int io_close_prep(struct io_kiocb *req, const struct io_uring_sqe *sqe)
{
/*
* If we queue this for async, it must not be cancellable. That would
* leave the 'file' in an undeterminate state, and here need to modify
* io_wq_work.flags, so initialize io_wq_work firstly.
*/
io_req_init_async(req);
req->work.flags |= IO_WQ_WORK_NO_CANCEL;
if (unlikely(req->ctx->flags & (IORING_SETUP_IOPOLL|IORING_SETUP_SQPOLL)))
return -EINVAL;
if (sqe->ioprio || sqe->off || sqe->addr || sqe->len ||
sqe->rw_flags || sqe->buf_index)
return -EINVAL;
if (req->flags & REQ_F_FIXED_FILE)
return -EBADF;
req->close.fd = READ_ONCE(sqe->fd);
if ((req->file && req->file->f_op == &io_uring_fops))
return -EBADF;
req->close.put_file = NULL;
return 0;
}
static int io_close(struct io_kiocb *req, bool force_nonblock,
struct io_comp_state *cs)
{
struct io_close *close = &req->close;
int ret;
/* might be already done during nonblock submission */
if (!close->put_file) {
ret = __close_fd_get_file(close->fd, &close->put_file);
if (ret < 0)
return (ret == -ENOENT) ? -EBADF : ret;
}
/* if the file has a flush method, be safe and punt to async */
if (close->put_file->f_op->flush && force_nonblock) {
/* was never set, but play safe */
req->flags &= ~REQ_F_NOWAIT;
/* avoid grabbing files - we don't need the files */
req->flags |= REQ_F_NO_FILE_TABLE;
return -EAGAIN;
}
/* No ->flush() or already async, safely close from here */
ret = filp_close(close->put_file, req->work.identity->files);
if (ret < 0)
req_set_fail_links(req);
fput(close->put_file);
close->put_file = NULL;
__io_req_complete(req, ret, 0, cs);
return 0;
}
static int io_prep_sfr(struct io_kiocb *req, const struct io_uring_sqe *sqe)
{
struct io_ring_ctx *ctx = req->ctx;
if (!req->file)
return -EBADF;
if (unlikely(ctx->flags & IORING_SETUP_IOPOLL))
return -EINVAL;
if (unlikely(sqe->addr || sqe->ioprio || sqe->buf_index))
return -EINVAL;
req->sync.off = READ_ONCE(sqe->off);
req->sync.len = READ_ONCE(sqe->len);
req->sync.flags = READ_ONCE(sqe->sync_range_flags);
return 0;
}
static int io_sync_file_range(struct io_kiocb *req, bool force_nonblock)
{
int ret;
/* sync_file_range always requires a blocking context */
if (force_nonblock)
return -EAGAIN;
ret = sync_file_range(req->file, req->sync.off, req->sync.len,
req->sync.flags);
if (ret < 0)
req_set_fail_links(req);
io_req_complete(req, ret);
return 0;
}
#if defined(CONFIG_NET)
static int io_setup_async_msg(struct io_kiocb *req,
struct io_async_msghdr *kmsg)
{
struct io_async_msghdr *async_msg = req->async_data;
if (async_msg)
return -EAGAIN;
if (io_alloc_async_data(req)) {
if (kmsg->iov != kmsg->fast_iov)
kfree(kmsg->iov);
return -ENOMEM;
}
async_msg = req->async_data;
req->flags |= REQ_F_NEED_CLEANUP;
memcpy(async_msg, kmsg, sizeof(*kmsg));
return -EAGAIN;
}
static int io_sendmsg_copy_hdr(struct io_kiocb *req,
struct io_async_msghdr *iomsg)
{
iomsg->iov = iomsg->fast_iov;
iomsg->msg.msg_name = &iomsg->addr;
return sendmsg_copy_msghdr(&iomsg->msg, req->sr_msg.umsg,
req->sr_msg.msg_flags, &iomsg->iov);
}
static int io_sendmsg_prep(struct io_kiocb *req, const struct io_uring_sqe *sqe)
{
struct io_async_msghdr *async_msg = req->async_data;
struct io_sr_msg *sr = &req->sr_msg;
int ret;
if (unlikely(req->ctx->flags & IORING_SETUP_IOPOLL))
return -EINVAL;
sr->msg_flags = READ_ONCE(sqe->msg_flags);
sr->umsg = u64_to_user_ptr(READ_ONCE(sqe->addr));
sr->len = READ_ONCE(sqe->len);
#ifdef CONFIG_COMPAT
if (req->ctx->compat)
sr->msg_flags |= MSG_CMSG_COMPAT;
#endif
if (!async_msg || !io_op_defs[req->opcode].needs_async_data)
return 0;
ret = io_sendmsg_copy_hdr(req, async_msg);
if (!ret)
req->flags |= REQ_F_NEED_CLEANUP;
return ret;
}
static int io_sendmsg(struct io_kiocb *req, bool force_nonblock,
struct io_comp_state *cs)
{
struct io_async_msghdr iomsg, *kmsg;
struct socket *sock;
unsigned flags;
int ret;
sock = sock_from_file(req->file, &ret);
if (unlikely(!sock))
return ret;
if (req->async_data) {
kmsg = req->async_data;
kmsg->msg.msg_name = &kmsg->addr;
/* if iov is set, it's allocated already */
if (!kmsg->iov)
kmsg->iov = kmsg->fast_iov;
kmsg->msg.msg_iter.iov = kmsg->iov;
} else {
ret = io_sendmsg_copy_hdr(req, &iomsg);
if (ret)
return ret;
kmsg = &iomsg;
}
flags = req->sr_msg.msg_flags;
if (flags & MSG_DONTWAIT)
req->flags |= REQ_F_NOWAIT;
else if (force_nonblock)
flags |= MSG_DONTWAIT;
ret = __sys_sendmsg_sock(sock, &kmsg->msg, flags);
if (force_nonblock && ret == -EAGAIN)
return io_setup_async_msg(req, kmsg);
if (ret == -ERESTARTSYS)
ret = -EINTR;
if (kmsg->iov != kmsg->fast_iov)
kfree(kmsg->iov);
req->flags &= ~REQ_F_NEED_CLEANUP;
if (ret < 0)
req_set_fail_links(req);
__io_req_complete(req, ret, 0, cs);
return 0;
}
static int io_send(struct io_kiocb *req, bool force_nonblock,
struct io_comp_state *cs)
{
struct io_sr_msg *sr = &req->sr_msg;
struct msghdr msg;
struct iovec iov;
struct socket *sock;
unsigned flags;
int ret;
sock = sock_from_file(req->file, &ret);
if (unlikely(!sock))
return ret;
ret = import_single_range(WRITE, sr->buf, sr->len, &iov, &msg.msg_iter);
if (unlikely(ret))
return ret;
msg.msg_name = NULL;
msg.msg_control = NULL;
msg.msg_controllen = 0;
msg.msg_namelen = 0;
flags = req->sr_msg.msg_flags;
if (flags & MSG_DONTWAIT)
req->flags |= REQ_F_NOWAIT;
else if (force_nonblock)
flags |= MSG_DONTWAIT;
msg.msg_flags = flags;
ret = sock_sendmsg(sock, &msg);
if (force_nonblock && ret == -EAGAIN)
return -EAGAIN;
if (ret == -ERESTARTSYS)
ret = -EINTR;
if (ret < 0)
req_set_fail_links(req);
__io_req_complete(req, ret, 0, cs);
return 0;
}
static int __io_recvmsg_copy_hdr(struct io_kiocb *req,
struct io_async_msghdr *iomsg)
{
struct io_sr_msg *sr = &req->sr_msg;
struct iovec __user *uiov;
size_t iov_len;
int ret;
ret = __copy_msghdr_from_user(&iomsg->msg, sr->umsg,
&iomsg->uaddr, &uiov, &iov_len);
if (ret)
return ret;
if (req->flags & REQ_F_BUFFER_SELECT) {
if (iov_len > 1)
return -EINVAL;
if (copy_from_user(iomsg->iov, uiov, sizeof(*uiov)))
return -EFAULT;
sr->len = iomsg->iov[0].iov_len;
iov_iter_init(&iomsg->msg.msg_iter, READ, iomsg->iov, 1,
sr->len);
iomsg->iov = NULL;
} else {
ret = __import_iovec(READ, uiov, iov_len, UIO_FASTIOV,
&iomsg->iov, &iomsg->msg.msg_iter,
false);
if (ret > 0)
ret = 0;
}
return ret;
}
#ifdef CONFIG_COMPAT
static int __io_compat_recvmsg_copy_hdr(struct io_kiocb *req,
struct io_async_msghdr *iomsg)
{
struct compat_msghdr __user *msg_compat;
struct io_sr_msg *sr = &req->sr_msg;
struct compat_iovec __user *uiov;
compat_uptr_t ptr;
compat_size_t len;
int ret;
msg_compat = (struct compat_msghdr __user *) sr->umsg;
ret = __get_compat_msghdr(&iomsg->msg, msg_compat, &iomsg->uaddr,
&ptr, &len);
if (ret)
return ret;
uiov = compat_ptr(ptr);
if (req->flags & REQ_F_BUFFER_SELECT) {
compat_ssize_t clen;
if (len > 1)
return -EINVAL;
if (!access_ok(uiov, sizeof(*uiov)))
return -EFAULT;
if (__get_user(clen, &uiov->iov_len))
return -EFAULT;
if (clen < 0)
return -EINVAL;
sr->len = clen;
iomsg->iov[0].iov_len = clen;
iomsg->iov = NULL;
} else {
ret = __import_iovec(READ, (struct iovec __user *)uiov, len,
UIO_FASTIOV, &iomsg->iov,
&iomsg->msg.msg_iter, true);
if (ret < 0)
return ret;
}
return 0;
}
#endif
static int io_recvmsg_copy_hdr(struct io_kiocb *req,
struct io_async_msghdr *iomsg)
{
iomsg->msg.msg_name = &iomsg->addr;
iomsg->iov = iomsg->fast_iov;
#ifdef CONFIG_COMPAT
if (req->ctx->compat)
return __io_compat_recvmsg_copy_hdr(req, iomsg);
#endif
return __io_recvmsg_copy_hdr(req, iomsg);
}
static struct io_buffer *io_recv_buffer_select(struct io_kiocb *req,
bool needs_lock)
{
struct io_sr_msg *sr = &req->sr_msg;
struct io_buffer *kbuf;
kbuf = io_buffer_select(req, &sr->len, sr->bgid, sr->kbuf, needs_lock);
if (IS_ERR(kbuf))
return kbuf;
sr->kbuf = kbuf;
req->flags |= REQ_F_BUFFER_SELECTED;
return kbuf;
}
static inline unsigned int io_put_recv_kbuf(struct io_kiocb *req)
{
return io_put_kbuf(req, req->sr_msg.kbuf);
}
static int io_recvmsg_prep(struct io_kiocb *req,
const struct io_uring_sqe *sqe)
{
struct io_async_msghdr *async_msg = req->async_data;
struct io_sr_msg *sr = &req->sr_msg;
int ret;
if (unlikely(req->ctx->flags & IORING_SETUP_IOPOLL))
return -EINVAL;
sr->msg_flags = READ_ONCE(sqe->msg_flags);
sr->umsg = u64_to_user_ptr(READ_ONCE(sqe->addr));
sr->len = READ_ONCE(sqe->len);
sr->bgid = READ_ONCE(sqe->buf_group);
#ifdef CONFIG_COMPAT
if (req->ctx->compat)
sr->msg_flags |= MSG_CMSG_COMPAT;
#endif
if (!async_msg || !io_op_defs[req->opcode].needs_async_data)
return 0;
ret = io_recvmsg_copy_hdr(req, async_msg);
if (!ret)
req->flags |= REQ_F_NEED_CLEANUP;
return ret;
}
static int io_recvmsg(struct io_kiocb *req, bool force_nonblock,
struct io_comp_state *cs)
{
struct io_async_msghdr iomsg, *kmsg;
struct socket *sock;
struct io_buffer *kbuf;
unsigned flags;
int ret, cflags = 0;
sock = sock_from_file(req->file, &ret);
if (unlikely(!sock))
return ret;
if (req->async_data) {
kmsg = req->async_data;
kmsg->msg.msg_name = &kmsg->addr;
/* if iov is set, it's allocated already */
if (!kmsg->iov)
kmsg->iov = kmsg->fast_iov;
kmsg->msg.msg_iter.iov = kmsg->iov;
} else {
ret = io_recvmsg_copy_hdr(req, &iomsg);
if (ret)
return ret;
kmsg = &iomsg;
}
if (req->flags & REQ_F_BUFFER_SELECT) {
kbuf = io_recv_buffer_select(req, !force_nonblock);
if (IS_ERR(kbuf))
return PTR_ERR(kbuf);
kmsg->fast_iov[0].iov_base = u64_to_user_ptr(kbuf->addr);
iov_iter_init(&kmsg->msg.msg_iter, READ, kmsg->iov,
1, req->sr_msg.len);
}
flags = req->sr_msg.msg_flags;
if (flags & MSG_DONTWAIT)
req->flags |= REQ_F_NOWAIT;
else if (force_nonblock)
flags |= MSG_DONTWAIT;
ret = __sys_recvmsg_sock(sock, &kmsg->msg, req->sr_msg.umsg,
kmsg->uaddr, flags);
if (force_nonblock && ret == -EAGAIN)
return io_setup_async_msg(req, kmsg);
if (ret == -ERESTARTSYS)
ret = -EINTR;
if (req->flags & REQ_F_BUFFER_SELECTED)
cflags = io_put_recv_kbuf(req);
if (kmsg->iov != kmsg->fast_iov)
kfree(kmsg->iov);
req->flags &= ~REQ_F_NEED_CLEANUP;
if (ret < 0)
req_set_fail_links(req);
__io_req_complete(req, ret, cflags, cs);
return 0;
}
static int io_recv(struct io_kiocb *req, bool force_nonblock,
struct io_comp_state *cs)
{
struct io_buffer *kbuf;
struct io_sr_msg *sr = &req->sr_msg;
struct msghdr msg;
void __user *buf = sr->buf;
struct socket *sock;
struct iovec iov;
unsigned flags;
int ret, cflags = 0;
sock = sock_from_file(req->file, &ret);
if (unlikely(!sock))
return ret;
if (req->flags & REQ_F_BUFFER_SELECT) {
kbuf = io_recv_buffer_select(req, !force_nonblock);
if (IS_ERR(kbuf))
return PTR_ERR(kbuf);
buf = u64_to_user_ptr(kbuf->addr);
}
ret = import_single_range(READ, buf, sr->len, &iov, &msg.msg_iter);
if (unlikely(ret))
goto out_free;
msg.msg_name = NULL;
msg.msg_control = NULL;
msg.msg_controllen = 0;
msg.msg_namelen = 0;
msg.msg_iocb = NULL;
msg.msg_flags = 0;
flags = req->sr_msg.msg_flags;
if (flags & MSG_DONTWAIT)
req->flags |= REQ_F_NOWAIT;
else if (force_nonblock)
flags |= MSG_DONTWAIT;
ret = sock_recvmsg(sock, &msg, flags);
if (force_nonblock && ret == -EAGAIN)
return -EAGAIN;
if (ret == -ERESTARTSYS)
ret = -EINTR;
out_free:
if (req->flags & REQ_F_BUFFER_SELECTED)
cflags = io_put_recv_kbuf(req);
if (ret < 0)
req_set_fail_links(req);
__io_req_complete(req, ret, cflags, cs);
return 0;
}
static int io_accept_prep(struct io_kiocb *req, const struct io_uring_sqe *sqe)
{
struct io_accept *accept = &req->accept;
if (unlikely(req->ctx->flags & (IORING_SETUP_IOPOLL|IORING_SETUP_SQPOLL)))
return -EINVAL;
if (sqe->ioprio || sqe->len || sqe->buf_index)
return -EINVAL;
accept->addr = u64_to_user_ptr(READ_ONCE(sqe->addr));
accept->addr_len = u64_to_user_ptr(READ_ONCE(sqe->addr2));
accept->flags = READ_ONCE(sqe->accept_flags);
accept->nofile = rlimit(RLIMIT_NOFILE);
return 0;
}
static int io_accept(struct io_kiocb *req, bool force_nonblock,
struct io_comp_state *cs)
{
struct io_accept *accept = &req->accept;
unsigned int file_flags = force_nonblock ? O_NONBLOCK : 0;
int ret;
if (req->file->f_flags & O_NONBLOCK)
req->flags |= REQ_F_NOWAIT;
ret = __sys_accept4_file(req->file, file_flags, accept->addr,
accept->addr_len, accept->flags,
accept->nofile);
if (ret == -EAGAIN && force_nonblock)
return -EAGAIN;
if (ret < 0) {
if (ret == -ERESTARTSYS)
ret = -EINTR;
req_set_fail_links(req);
}
__io_req_complete(req, ret, 0, cs);
return 0;
}
static int io_connect_prep(struct io_kiocb *req, const struct io_uring_sqe *sqe)
{
struct io_connect *conn = &req->connect;
struct io_async_connect *io = req->async_data;
if (unlikely(req->ctx->flags & (IORING_SETUP_IOPOLL|IORING_SETUP_SQPOLL)))
return -EINVAL;
if (sqe->ioprio || sqe->len || sqe->buf_index || sqe->rw_flags)
return -EINVAL;
conn->addr = u64_to_user_ptr(READ_ONCE(sqe->addr));
conn->addr_len = READ_ONCE(sqe->addr2);
if (!io)
return 0;
return move_addr_to_kernel(conn->addr, conn->addr_len,
&io->address);
}
static int io_connect(struct io_kiocb *req, bool force_nonblock,
struct io_comp_state *cs)
{
struct io_async_connect __io, *io;
unsigned file_flags;
int ret;
if (req->async_data) {
io = req->async_data;
} else {
ret = move_addr_to_kernel(req->connect.addr,
req->connect.addr_len,
&__io.address);
if (ret)
goto out;
io = &__io;
}
file_flags = force_nonblock ? O_NONBLOCK : 0;
ret = __sys_connect_file(req->file, &io->address,
req->connect.addr_len, file_flags);
if ((ret == -EAGAIN || ret == -EINPROGRESS) && force_nonblock) {
if (req->async_data)
return -EAGAIN;
if (io_alloc_async_data(req)) {
ret = -ENOMEM;
goto out;
}
io = req->async_data;
memcpy(req->async_data, &__io, sizeof(__io));
return -EAGAIN;
}
if (ret == -ERESTARTSYS)
ret = -EINTR;
out:
if (ret < 0)
req_set_fail_links(req);
__io_req_complete(req, ret, 0, cs);
return 0;
}
#else /* !CONFIG_NET */
static int io_sendmsg_prep(struct io_kiocb *req, const struct io_uring_sqe *sqe)
{
return -EOPNOTSUPP;
}
static int io_sendmsg(struct io_kiocb *req, bool force_nonblock,
struct io_comp_state *cs)
{
return -EOPNOTSUPP;
}
static int io_send(struct io_kiocb *req, bool force_nonblock,
struct io_comp_state *cs)
{
return -EOPNOTSUPP;
}
static int io_recvmsg_prep(struct io_kiocb *req,
const struct io_uring_sqe *sqe)
{
return -EOPNOTSUPP;
}
static int io_recvmsg(struct io_kiocb *req, bool force_nonblock,
struct io_comp_state *cs)
{
return -EOPNOTSUPP;
}
static int io_recv(struct io_kiocb *req, bool force_nonblock,
struct io_comp_state *cs)
{
return -EOPNOTSUPP;
}
static int io_accept_prep(struct io_kiocb *req, const struct io_uring_sqe *sqe)
{
return -EOPNOTSUPP;
}
static int io_accept(struct io_kiocb *req, bool force_nonblock,
struct io_comp_state *cs)
{
return -EOPNOTSUPP;
}
static int io_connect_prep(struct io_kiocb *req, const struct io_uring_sqe *sqe)
{
return -EOPNOTSUPP;
}
static int io_connect(struct io_kiocb *req, bool force_nonblock,
struct io_comp_state *cs)
{
return -EOPNOTSUPP;
}
#endif /* CONFIG_NET */
struct io_poll_table {
struct poll_table_struct pt;
struct io_kiocb *req;
int error;
};
static int __io_async_wake(struct io_kiocb *req, struct io_poll_iocb *poll,
__poll_t mask, task_work_func_t func)
{
bool twa_signal_ok;
int ret;
/* for instances that support it check for an event match first: */
if (mask && !(mask & poll->events))
return 0;
trace_io_uring_task_add(req->ctx, req->opcode, req->user_data, mask);
list_del_init(&poll->wait.entry);
req->result = mask;
init_task_work(&req->task_work, func);
percpu_ref_get(&req->ctx->refs);
/*
* If we using the signalfd wait_queue_head for this wakeup, then
* it's not safe to use TWA_SIGNAL as we could be recursing on the
* tsk->sighand->siglock on doing the wakeup. Should not be needed
* either, as the normal wakeup will suffice.
*/
twa_signal_ok = (poll->head != &req->task->sighand->signalfd_wqh);
/*
* If this fails, then the task is exiting. When a task exits, the
* work gets canceled, so just cancel this request as well instead
* of executing it. We can't safely execute it anyway, as we may not
* have the needed state needed for it anyway.
*/
ret = io_req_task_work_add(req, twa_signal_ok);
if (unlikely(ret)) {
struct task_struct *tsk;
WRITE_ONCE(poll->canceled, true);
tsk = io_wq_get_task(req->ctx->io_wq);
task_work_add(tsk, &req->task_work, TWA_NONE);
wake_up_process(tsk);
}
return 1;
}
static bool io_poll_rewait(struct io_kiocb *req, struct io_poll_iocb *poll)
__acquires(&req->ctx->completion_lock)
{
struct io_ring_ctx *ctx = req->ctx;
if (!req->result && !READ_ONCE(poll->canceled)) {
struct poll_table_struct pt = { ._key = poll->events };
req->result = vfs_poll(req->file, &pt) & poll->events;
}
spin_lock_irq(&ctx->completion_lock);
if (!req->result && !READ_ONCE(poll->canceled)) {
add_wait_queue(poll->head, &poll->wait);
return true;
}
return false;
}
static struct io_poll_iocb *io_poll_get_double(struct io_kiocb *req)
{
/* pure poll stashes this in ->async_data, poll driven retry elsewhere */
if (req->opcode == IORING_OP_POLL_ADD)
return req->async_data;
return req->apoll->double_poll;
}
static struct io_poll_iocb *io_poll_get_single(struct io_kiocb *req)
{
if (req->opcode == IORING_OP_POLL_ADD)
return &req->poll;
return &req->apoll->poll;
}
static void io_poll_remove_double(struct io_kiocb *req)
{
struct io_poll_iocb *poll = io_poll_get_double(req);
lockdep_assert_held(&req->ctx->completion_lock);
if (poll && poll->head) {
struct wait_queue_head *head = poll->head;
spin_lock(&head->lock);
list_del_init(&poll->wait.entry);
if (poll->wait.private)
refcount_dec(&req->refs);
poll->head = NULL;
spin_unlock(&head->lock);
}
}
static void io_poll_complete(struct io_kiocb *req, __poll_t mask, int error)
{
struct io_ring_ctx *ctx = req->ctx;
io_poll_remove_double(req);
req->poll.done = true;
io_cqring_fill_event(req, error ? error : mangle_poll(mask));
io_commit_cqring(ctx);
}
static void io_poll_task_func(struct callback_head *cb)
{
struct io_kiocb *req = container_of(cb, struct io_kiocb, task_work);
struct io_ring_ctx *ctx = req->ctx;
struct io_kiocb *nxt;
if (io_poll_rewait(req, &req->poll)) {
spin_unlock_irq(&ctx->completion_lock);
} else {
hash_del(&req->hash_node);
io_poll_complete(req, req->result, 0);
spin_unlock_irq(&ctx->completion_lock);
nxt = io_put_req_find_next(req);
io_cqring_ev_posted(ctx);
if (nxt)
__io_req_task_submit(nxt);
}
percpu_ref_put(&ctx->refs);
}
static int io_poll_double_wake(struct wait_queue_entry *wait, unsigned mode,
int sync, void *key)
{
struct io_kiocb *req = wait->private;
struct io_poll_iocb *poll = io_poll_get_single(req);
__poll_t mask = key_to_poll(key);
/* for instances that support it check for an event match first: */
if (mask && !(mask & poll->events))
return 0;
list_del_init(&wait->entry);
if (poll && poll->head) {
bool done;
spin_lock(&poll->head->lock);
done = list_empty(&poll->wait.entry);
if (!done)
list_del_init(&poll->wait.entry);
/* make sure double remove sees this as being gone */
wait->private = NULL;
spin_unlock(&poll->head->lock);
if (!done) {
/* use wait func handler, so it matches the rq type */
poll->wait.func(&poll->wait, mode, sync, key);
}
}
refcount_dec(&req->refs);
return 1;
}
static void io_init_poll_iocb(struct io_poll_iocb *poll, __poll_t events,
wait_queue_func_t wake_func)
{
poll->head = NULL;
poll->done = false;
poll->canceled = false;
poll->events = events;
INIT_LIST_HEAD(&poll->wait.entry);
init_waitqueue_func_entry(&poll->wait, wake_func);
}
static void __io_queue_proc(struct io_poll_iocb *poll, struct io_poll_table *pt,
struct wait_queue_head *head,
struct io_poll_iocb **poll_ptr)
{
struct io_kiocb *req = pt->req;
/*
* If poll->head is already set, it's because the file being polled
* uses multiple waitqueues for poll handling (eg one for read, one
* for write). Setup a separate io_poll_iocb if this happens.
*/
if (unlikely(poll->head)) {
struct io_poll_iocb *poll_one = poll;
/* already have a 2nd entry, fail a third attempt */
if (*poll_ptr) {
pt->error = -EINVAL;
return;
}
poll = kmalloc(sizeof(*poll), GFP_ATOMIC);
if (!poll) {
pt->error = -ENOMEM;
return;
}
io_init_poll_iocb(poll, poll_one->events, io_poll_double_wake);
refcount_inc(&req->refs);
poll->wait.private = req;
*poll_ptr = poll;
}
pt->error = 0;
poll->head = head;
if (poll->events & EPOLLEXCLUSIVE)
add_wait_queue_exclusive(head, &poll->wait);
else
add_wait_queue(head, &poll->wait);
}
static void io_async_queue_proc(struct file *file, struct wait_queue_head *head,
struct poll_table_struct *p)
{
struct io_poll_table *pt = container_of(p, struct io_poll_table, pt);
struct async_poll *apoll = pt->req->apoll;
__io_queue_proc(&apoll->poll, pt, head, &apoll->double_poll);
}
static void io_async_task_func(struct callback_head *cb)
{
struct io_kiocb *req = container_of(cb, struct io_kiocb, task_work);
struct async_poll *apoll = req->apoll;
struct io_ring_ctx *ctx = req->ctx;
trace_io_uring_task_run(req->ctx, req->opcode, req->user_data);
if (io_poll_rewait(req, &apoll->poll)) {
spin_unlock_irq(&ctx->completion_lock);
percpu_ref_put(&ctx->refs);
return;
}
/* If req is still hashed, it cannot have been canceled. Don't check. */
if (hash_hashed(&req->hash_node))
hash_del(&req->hash_node);
io_poll_remove_double(req);
spin_unlock_irq(&ctx->completion_lock);
if (!READ_ONCE(apoll->poll.canceled))
__io_req_task_submit(req);
else
__io_req_task_cancel(req, -ECANCELED);
percpu_ref_put(&ctx->refs);
kfree(apoll->double_poll);
kfree(apoll);
}
static int io_async_wake(struct wait_queue_entry *wait, unsigned mode, int sync,
void *key)
{
struct io_kiocb *req = wait->private;
struct io_poll_iocb *poll = &req->apoll->poll;
trace_io_uring_poll_wake(req->ctx, req->opcode, req->user_data,
key_to_poll(key));
return __io_async_wake(req, poll, key_to_poll(key), io_async_task_func);
}
static void io_poll_req_insert(struct io_kiocb *req)
{
struct io_ring_ctx *ctx = req->ctx;
struct hlist_head *list;
list = &ctx->cancel_hash[hash_long(req->user_data, ctx->cancel_hash_bits)];
hlist_add_head(&req->hash_node, list);
}
static __poll_t __io_arm_poll_handler(struct io_kiocb *req,
struct io_poll_iocb *poll,
struct io_poll_table *ipt, __poll_t mask,
wait_queue_func_t wake_func)
__acquires(&ctx->completion_lock)
{
struct io_ring_ctx *ctx = req->ctx;
bool cancel = false;
INIT_HLIST_NODE(&req->hash_node);
io_init_poll_iocb(poll, mask, wake_func);
poll->file = req->file;
poll->wait.private = req;
ipt->pt._key = mask;
ipt->req = req;
ipt->error = -EINVAL;
mask = vfs_poll(req->file, &ipt->pt) & poll->events;
spin_lock_irq(&ctx->completion_lock);
if (likely(poll->head)) {
spin_lock(&poll->head->lock);
if (unlikely(list_empty(&poll->wait.entry))) {
if (ipt->error)
cancel = true;
ipt->error = 0;
mask = 0;
}
if (mask || ipt->error)
list_del_init(&poll->wait.entry);
else if (cancel)
WRITE_ONCE(poll->canceled, true);
else if (!poll->done) /* actually waiting for an event */
io_poll_req_insert(req);
spin_unlock(&poll->head->lock);
}
return mask;
}
static bool io_arm_poll_handler(struct io_kiocb *req)
{
const struct io_op_def *def = &io_op_defs[req->opcode];
struct io_ring_ctx *ctx = req->ctx;
struct async_poll *apoll;
struct io_poll_table ipt;
__poll_t mask, ret;
int rw;
if (!req->file || !file_can_poll(req->file))
return false;
if (req->flags & REQ_F_POLLED)
return false;
if (def->pollin)
rw = READ;
else if (def->pollout)
rw = WRITE;
else
return false;
/* if we can't nonblock try, then no point in arming a poll handler */
if (!io_file_supports_async(req->file, rw))
return false;
apoll = kmalloc(sizeof(*apoll), GFP_ATOMIC);
if (unlikely(!apoll))
return false;
apoll->double_poll = NULL;
req->flags |= REQ_F_POLLED;
req->apoll = apoll;
mask = 0;
if (def->pollin)
mask |= POLLIN | POLLRDNORM;
if (def->pollout)
mask |= POLLOUT | POLLWRNORM;
/* If reading from MSG_ERRQUEUE using recvmsg, ignore POLLIN */
if ((req->opcode == IORING_OP_RECVMSG) &&
(req->sr_msg.msg_flags & MSG_ERRQUEUE))
mask &= ~POLLIN;
mask |= POLLERR | POLLPRI;
ipt.pt._qproc = io_async_queue_proc;
ret = __io_arm_poll_handler(req, &apoll->poll, &ipt, mask,
io_async_wake);
if (ret || ipt.error) {
io_poll_remove_double(req);
spin_unlock_irq(&ctx->completion_lock);
kfree(apoll->double_poll);
kfree(apoll);
return false;
}
spin_unlock_irq(&ctx->completion_lock);
trace_io_uring_poll_arm(ctx, req->opcode, req->user_data, mask,
apoll->poll.events);
return true;
}
static bool __io_poll_remove_one(struct io_kiocb *req,
struct io_poll_iocb *poll)
{
bool do_complete = false;
spin_lock(&poll->head->lock);
WRITE_ONCE(poll->canceled, true);
if (!list_empty(&poll->wait.entry)) {
list_del_init(&poll->wait.entry);
do_complete = true;
}
spin_unlock(&poll->head->lock);
hash_del(&req->hash_node);
return do_complete;
}
static bool io_poll_remove_one(struct io_kiocb *req)
{
bool do_complete;
io_poll_remove_double(req);
if (req->opcode == IORING_OP_POLL_ADD) {
do_complete = __io_poll_remove_one(req, &req->poll);
} else {
struct async_poll *apoll = req->apoll;
/* non-poll requests have submit ref still */
do_complete = __io_poll_remove_one(req, &apoll->poll);
if (do_complete) {
io_put_req(req);
kfree(apoll->double_poll);
kfree(apoll);
}
}
if (do_complete) {
io_cqring_fill_event(req, -ECANCELED);
io_commit_cqring(req->ctx);
req_set_fail_links(req);
io_put_req_deferred(req, 1);
}
return do_complete;
}
/*
* Returns true if we found and killed one or more poll requests
*/
static bool io_poll_remove_all(struct io_ring_ctx *ctx, struct task_struct *tsk)
{
struct hlist_node *tmp;
struct io_kiocb *req;
int posted = 0, i;
spin_lock_irq(&ctx->completion_lock);
for (i = 0; i < (1U << ctx->cancel_hash_bits); i++) {
struct hlist_head *list;
list = &ctx->cancel_hash[i];
hlist_for_each_entry_safe(req, tmp, list, hash_node) {
if (io_task_match(req, tsk))
posted += io_poll_remove_one(req);
}
}
spin_unlock_irq(&ctx->completion_lock);
if (posted)
io_cqring_ev_posted(ctx);
return posted != 0;
}
static int io_poll_cancel(struct io_ring_ctx *ctx, __u64 sqe_addr)
{
struct hlist_head *list;
struct io_kiocb *req;
list = &ctx->cancel_hash[hash_long(sqe_addr, ctx->cancel_hash_bits)];
hlist_for_each_entry(req, list, hash_node) {
if (sqe_addr != req->user_data)
continue;
if (io_poll_remove_one(req))
return 0;
return -EALREADY;
}
return -ENOENT;
}
static int io_poll_remove_prep(struct io_kiocb *req,
const struct io_uring_sqe *sqe)
{
if (unlikely(req->ctx->flags & IORING_SETUP_IOPOLL))
return -EINVAL;
if (sqe->ioprio || sqe->off || sqe->len || sqe->buf_index ||
sqe->poll_events)
return -EINVAL;
req->poll.addr = READ_ONCE(sqe->addr);
return 0;
}
/*
* Find a running poll command that matches one specified in sqe->addr,
* and remove it if found.
*/
static int io_poll_remove(struct io_kiocb *req)
{
struct io_ring_ctx *ctx = req->ctx;
u64 addr;
int ret;
addr = req->poll.addr;
spin_lock_irq(&ctx->completion_lock);
ret = io_poll_cancel(ctx, addr);
spin_unlock_irq(&ctx->completion_lock);
if (ret < 0)
req_set_fail_links(req);
io_req_complete(req, ret);
return 0;
}
static int io_poll_wake(struct wait_queue_entry *wait, unsigned mode, int sync,
void *key)
{
struct io_kiocb *req = wait->private;
struct io_poll_iocb *poll = &req->poll;
return __io_async_wake(req, poll, key_to_poll(key), io_poll_task_func);
}
static void io_poll_queue_proc(struct file *file, struct wait_queue_head *head,
struct poll_table_struct *p)
{
struct io_poll_table *pt = container_of(p, struct io_poll_table, pt);
__io_queue_proc(&pt->req->poll, pt, head, (struct io_poll_iocb **) &pt->req->async_data);
}
static int io_poll_add_prep(struct io_kiocb *req, const struct io_uring_sqe *sqe)
{
struct io_poll_iocb *poll = &req->poll;
u32 events;
if (unlikely(req->ctx->flags & IORING_SETUP_IOPOLL))
return -EINVAL;
if (sqe->addr || sqe->ioprio || sqe->off || sqe->len || sqe->buf_index)
return -EINVAL;
events = READ_ONCE(sqe->poll32_events);
#ifdef __BIG_ENDIAN
events = swahw32(events);
#endif
poll->events = demangle_poll(events) | EPOLLERR | EPOLLHUP |
(events & EPOLLEXCLUSIVE);
return 0;
}
static int io_poll_add(struct io_kiocb *req)
{
struct io_poll_iocb *poll = &req->poll;
struct io_ring_ctx *ctx = req->ctx;
struct io_poll_table ipt;
__poll_t mask;
ipt.pt._qproc = io_poll_queue_proc;
mask = __io_arm_poll_handler(req, &req->poll, &ipt, poll->events,
io_poll_wake);
if (mask) { /* no async, we'd stolen it */
ipt.error = 0;
io_poll_complete(req, mask, 0);
}
spin_unlock_irq(&ctx->completion_lock);
if (mask) {
io_cqring_ev_posted(ctx);
io_put_req(req);
}
return ipt.error;
}
static enum hrtimer_restart io_timeout_fn(struct hrtimer *timer)
{
struct io_timeout_data *data = container_of(timer,
struct io_timeout_data, timer);
struct io_kiocb *req = data->req;
struct io_ring_ctx *ctx = req->ctx;
unsigned long flags;
spin_lock_irqsave(&ctx->completion_lock, flags);
list_del_init(&req->timeout.list);
atomic_set(&req->ctx->cq_timeouts,
atomic_read(&req->ctx->cq_timeouts) + 1);
io_cqring_fill_event(req, -ETIME);
io_commit_cqring(ctx);
spin_unlock_irqrestore(&ctx->completion_lock, flags);
io_cqring_ev_posted(ctx);
req_set_fail_links(req);
io_put_req(req);
return HRTIMER_NORESTART;
}
static int __io_timeout_cancel(struct io_kiocb *req)
{
struct io_timeout_data *io = req->async_data;
int ret;
ret = hrtimer_try_to_cancel(&io->timer);
if (ret == -1)
return -EALREADY;
list_del_init(&req->timeout.list);
req_set_fail_links(req);
io_cqring_fill_event(req, -ECANCELED);
io_put_req_deferred(req, 1);
return 0;
}
static int io_timeout_cancel(struct io_ring_ctx *ctx, __u64 user_data)
{
struct io_kiocb *req;
int ret = -ENOENT;
list_for_each_entry(req, &ctx->timeout_list, timeout.list) {
if (user_data == req->user_data) {
ret = 0;
break;
}
}
if (ret == -ENOENT)
return ret;
return __io_timeout_cancel(req);
}
static int io_timeout_remove_prep(struct io_kiocb *req,
const struct io_uring_sqe *sqe)
{
if (unlikely(req->ctx->flags & IORING_SETUP_IOPOLL))
return -EINVAL;
if (unlikely(req->flags & (REQ_F_FIXED_FILE | REQ_F_BUFFER_SELECT)))
return -EINVAL;
if (sqe->ioprio || sqe->buf_index || sqe->len || sqe->timeout_flags)
return -EINVAL;
req->timeout_rem.addr = READ_ONCE(sqe->addr);
return 0;
}
/*
* Remove or update an existing timeout command
*/
static int io_timeout_remove(struct io_kiocb *req)
{
struct io_ring_ctx *ctx = req->ctx;
int ret;
spin_lock_irq(&ctx->completion_lock);
ret = io_timeout_cancel(ctx, req->timeout_rem.addr);
io_cqring_fill_event(req, ret);
io_commit_cqring(ctx);
spin_unlock_irq(&ctx->completion_lock);
io_cqring_ev_posted(ctx);
if (ret < 0)
req_set_fail_links(req);
io_put_req(req);
return 0;
}
static int io_timeout_prep(struct io_kiocb *req, const struct io_uring_sqe *sqe,
bool is_timeout_link)
{
struct io_timeout_data *data;
unsigned flags;
u32 off = READ_ONCE(sqe->off);
if (unlikely(req->ctx->flags & IORING_SETUP_IOPOLL))
return -EINVAL;
if (sqe->ioprio || sqe->buf_index || sqe->len != 1)
return -EINVAL;
if (off && is_timeout_link)
return -EINVAL;
flags = READ_ONCE(sqe->timeout_flags);
if (flags & ~IORING_TIMEOUT_ABS)
return -EINVAL;
req->timeout.off = off;
if (!req->async_data && io_alloc_async_data(req))
return -ENOMEM;
data = req->async_data;
data->req = req;
if (get_timespec64(&data->ts, u64_to_user_ptr(sqe->addr)))
return -EFAULT;
if (flags & IORING_TIMEOUT_ABS)
data->mode = HRTIMER_MODE_ABS;
else
data->mode = HRTIMER_MODE_REL;
hrtimer_init(&data->timer, CLOCK_MONOTONIC, data->mode);
return 0;
}
static int io_timeout(struct io_kiocb *req)
{
struct io_ring_ctx *ctx = req->ctx;
struct io_timeout_data *data = req->async_data;
struct list_head *entry;
u32 tail, off = req->timeout.off;
spin_lock_irq(&ctx->completion_lock);
/*
* sqe->off holds how many events that need to occur for this
* timeout event to be satisfied. If it isn't set, then this is
* a pure timeout request, sequence isn't used.
*/
if (io_is_timeout_noseq(req)) {
entry = ctx->timeout_list.prev;
goto add;
}
tail = ctx->cached_cq_tail - atomic_read(&ctx->cq_timeouts);
req->timeout.target_seq = tail + off;
/*
* Insertion sort, ensuring the first entry in the list is always
* the one we need first.
*/
list_for_each_prev(entry, &ctx->timeout_list) {
struct io_kiocb *nxt = list_entry(entry, struct io_kiocb,
timeout.list);
if (io_is_timeout_noseq(nxt))
continue;
/* nxt.seq is behind @tail, otherwise would've been completed */
if (off >= nxt->timeout.target_seq - tail)
break;
}
add:
list_add(&req->timeout.list, entry);
data->timer.function = io_timeout_fn;
hrtimer_start(&data->timer, timespec64_to_ktime(data->ts), data->mode);
spin_unlock_irq(&ctx->completion_lock);
return 0;
}
static bool io_cancel_cb(struct io_wq_work *work, void *data)
{
struct io_kiocb *req = container_of(work, struct io_kiocb, work);
return req->user_data == (unsigned long) data;
}
static int io_async_cancel_one(struct io_ring_ctx *ctx, void *sqe_addr)
{
enum io_wq_cancel cancel_ret;
int ret = 0;
cancel_ret = io_wq_cancel_cb(ctx->io_wq, io_cancel_cb, sqe_addr, false);
switch (cancel_ret) {
case IO_WQ_CANCEL_OK:
ret = 0;
break;
case IO_WQ_CANCEL_RUNNING:
ret = -EALREADY;
break;
case IO_WQ_CANCEL_NOTFOUND:
ret = -ENOENT;
break;
}
return ret;
}
static void io_async_find_and_cancel(struct io_ring_ctx *ctx,
struct io_kiocb *req, __u64 sqe_addr,
int success_ret)
{
unsigned long flags;
int ret;
ret = io_async_cancel_one(ctx, (void *) (unsigned long) sqe_addr);
if (ret != -ENOENT) {
spin_lock_irqsave(&ctx->completion_lock, flags);
goto done;
}
spin_lock_irqsave(&ctx->completion_lock, flags);
ret = io_timeout_cancel(ctx, sqe_addr);
if (ret != -ENOENT)
goto done;
ret = io_poll_cancel(ctx, sqe_addr);
done:
if (!ret)
ret = success_ret;
io_cqring_fill_event(req, ret);
io_commit_cqring(ctx);
spin_unlock_irqrestore(&ctx->completion_lock, flags);
io_cqring_ev_posted(ctx);
if (ret < 0)
req_set_fail_links(req);
io_put_req(req);
}
static int io_async_cancel_prep(struct io_kiocb *req,
const struct io_uring_sqe *sqe)
{
if (unlikely(req->ctx->flags & IORING_SETUP_IOPOLL))
return -EINVAL;
if (unlikely(req->flags & (REQ_F_FIXED_FILE | REQ_F_BUFFER_SELECT)))
return -EINVAL;
if (sqe->ioprio || sqe->off || sqe->len || sqe->cancel_flags)
return -EINVAL;
req->cancel.addr = READ_ONCE(sqe->addr);
return 0;
}
static int io_async_cancel(struct io_kiocb *req)
{
struct io_ring_ctx *ctx = req->ctx;
io_async_find_and_cancel(ctx, req, req->cancel.addr, 0);
return 0;
}
static int io_files_update_prep(struct io_kiocb *req,
const struct io_uring_sqe *sqe)
{
if (unlikely(req->ctx->flags & IORING_SETUP_SQPOLL))
return -EINVAL;
if (unlikely(req->flags & (REQ_F_FIXED_FILE | REQ_F_BUFFER_SELECT)))
return -EINVAL;
if (sqe->ioprio || sqe->rw_flags)
return -EINVAL;
req->files_update.offset = READ_ONCE(sqe->off);
req->files_update.nr_args = READ_ONCE(sqe->len);
if (!req->files_update.nr_args)
return -EINVAL;
req->files_update.arg = READ_ONCE(sqe->addr);
return 0;
}
static int io_files_update(struct io_kiocb *req, bool force_nonblock,
struct io_comp_state *cs)
{
struct io_ring_ctx *ctx = req->ctx;
struct io_uring_files_update up;
int ret;
if (force_nonblock)
return -EAGAIN;
up.offset = req->files_update.offset;
up.fds = req->files_update.arg;
mutex_lock(&ctx->uring_lock);
ret = __io_sqe_files_update(ctx, &up, req->files_update.nr_args);
mutex_unlock(&ctx->uring_lock);
if (ret < 0)
req_set_fail_links(req);
__io_req_complete(req, ret, 0, cs);
return 0;
}
static int io_req_prep(struct io_kiocb *req, const struct io_uring_sqe *sqe)
{
switch (req->opcode) {
case IORING_OP_NOP:
return 0;
case IORING_OP_READV:
case IORING_OP_READ_FIXED:
case IORING_OP_READ:
return io_read_prep(req, sqe);
case IORING_OP_WRITEV:
case IORING_OP_WRITE_FIXED:
case IORING_OP_WRITE:
return io_write_prep(req, sqe);
case IORING_OP_POLL_ADD:
return io_poll_add_prep(req, sqe);
case IORING_OP_POLL_REMOVE:
return io_poll_remove_prep(req, sqe);
case IORING_OP_FSYNC:
return io_prep_fsync(req, sqe);
case IORING_OP_SYNC_FILE_RANGE:
return io_prep_sfr(req, sqe);
case IORING_OP_SENDMSG:
case IORING_OP_SEND:
return io_sendmsg_prep(req, sqe);
case IORING_OP_RECVMSG:
case IORING_OP_RECV:
return io_recvmsg_prep(req, sqe);
case IORING_OP_CONNECT:
return io_connect_prep(req, sqe);
case IORING_OP_TIMEOUT:
return io_timeout_prep(req, sqe, false);
case IORING_OP_TIMEOUT_REMOVE:
return io_timeout_remove_prep(req, sqe);
case IORING_OP_ASYNC_CANCEL:
return io_async_cancel_prep(req, sqe);
case IORING_OP_LINK_TIMEOUT:
return io_timeout_prep(req, sqe, true);
case IORING_OP_ACCEPT:
return io_accept_prep(req, sqe);
case IORING_OP_FALLOCATE:
return io_fallocate_prep(req, sqe);
case IORING_OP_OPENAT:
return io_openat_prep(req, sqe);
case IORING_OP_CLOSE:
return io_close_prep(req, sqe);
case IORING_OP_FILES_UPDATE:
return io_files_update_prep(req, sqe);
case IORING_OP_STATX:
return io_statx_prep(req, sqe);
case IORING_OP_FADVISE:
return io_fadvise_prep(req, sqe);
case IORING_OP_MADVISE:
return io_madvise_prep(req, sqe);
case IORING_OP_OPENAT2:
return io_openat2_prep(req, sqe);
case IORING_OP_EPOLL_CTL:
return io_epoll_ctl_prep(req, sqe);
case IORING_OP_SPLICE:
return io_splice_prep(req, sqe);
case IORING_OP_PROVIDE_BUFFERS:
return io_provide_buffers_prep(req, sqe);
case IORING_OP_REMOVE_BUFFERS:
return io_remove_buffers_prep(req, sqe);
case IORING_OP_TEE:
return io_tee_prep(req, sqe);
}
printk_once(KERN_WARNING "io_uring: unhandled opcode %d\n",
req->opcode);
return-EINVAL;
}
static int io_req_defer_prep(struct io_kiocb *req,
const struct io_uring_sqe *sqe)
{
if (!sqe)
return 0;
if (io_alloc_async_data(req))
return -EAGAIN;
return io_req_prep(req, sqe);
}
static u32 io_get_sequence(struct io_kiocb *req)
{
struct io_kiocb *pos;
struct io_ring_ctx *ctx = req->ctx;
u32 total_submitted, nr_reqs = 1;
if (req->flags & REQ_F_LINK_HEAD)
list_for_each_entry(pos, &req->link_list, link_list)
nr_reqs++;
total_submitted = ctx->cached_sq_head - ctx->cached_sq_dropped;
return total_submitted - nr_reqs;
}
static int io_req_defer(struct io_kiocb *req, const struct io_uring_sqe *sqe)
{
struct io_ring_ctx *ctx = req->ctx;
struct io_defer_entry *de;
int ret;
u32 seq;
/* Still need defer if there is pending req in defer list. */
if (likely(list_empty_careful(&ctx->defer_list) &&
!(req->flags & REQ_F_IO_DRAIN)))
return 0;
seq = io_get_sequence(req);
/* Still a chance to pass the sequence check */
if (!req_need_defer(req, seq) && list_empty_careful(&ctx->defer_list))
return 0;
if (!req->async_data) {
ret = io_req_defer_prep(req, sqe);
if (ret)
return ret;
}
io_prep_async_link(req);
de = kmalloc(sizeof(*de), GFP_KERNEL);
if (!de)
return -ENOMEM;
spin_lock_irq(&ctx->completion_lock);
if (!req_need_defer(req, seq) && list_empty(&ctx->defer_list)) {
spin_unlock_irq(&ctx->completion_lock);
kfree(de);
io_queue_async_work(req);
return -EIOCBQUEUED;
}
trace_io_uring_defer(ctx, req, req->user_data);
de->req = req;
de->seq = seq;
list_add_tail(&de->list, &ctx->defer_list);
spin_unlock_irq(&ctx->completion_lock);
return -EIOCBQUEUED;
}
static void io_req_drop_files(struct io_kiocb *req)
{
struct io_ring_ctx *ctx = req->ctx;
unsigned long flags;
spin_lock_irqsave(&ctx->inflight_lock, flags);
list_del(&req->inflight_entry);
if (waitqueue_active(&ctx->inflight_wait))
wake_up(&ctx->inflight_wait);
spin_unlock_irqrestore(&ctx->inflight_lock, flags);
req->flags &= ~REQ_F_INFLIGHT;
put_files_struct(req->work.identity->files);
put_nsproxy(req->work.identity->nsproxy);
req->work.flags &= ~IO_WQ_WORK_FILES;
}
static void __io_clean_op(struct io_kiocb *req)
{
if (req->flags & REQ_F_BUFFER_SELECTED) {
switch (req->opcode) {
case IORING_OP_READV:
case IORING_OP_READ_FIXED:
case IORING_OP_READ:
kfree((void *)(unsigned long)req->rw.addr);
break;
case IORING_OP_RECVMSG:
case IORING_OP_RECV:
kfree(req->sr_msg.kbuf);
break;
}
req->flags &= ~REQ_F_BUFFER_SELECTED;
}
if (req->flags & REQ_F_NEED_CLEANUP) {
switch (req->opcode) {
case IORING_OP_READV:
case IORING_OP_READ_FIXED:
case IORING_OP_READ:
case IORING_OP_WRITEV:
case IORING_OP_WRITE_FIXED:
case IORING_OP_WRITE: {
struct io_async_rw *io = req->async_data;
if (io->free_iovec)
kfree(io->free_iovec);
break;
}
case IORING_OP_RECVMSG:
case IORING_OP_SENDMSG: {
struct io_async_msghdr *io = req->async_data;
if (io->iov != io->fast_iov)
kfree(io->iov);
break;
}
case IORING_OP_SPLICE:
case IORING_OP_TEE:
io_put_file(req, req->splice.file_in,
(req->splice.flags & SPLICE_F_FD_IN_FIXED));
break;
case IORING_OP_OPENAT:
case IORING_OP_OPENAT2:
if (req->open.filename)
putname(req->open.filename);
break;
}
req->flags &= ~REQ_F_NEED_CLEANUP;
}
if (req->flags & REQ_F_INFLIGHT)
io_req_drop_files(req);
}
static int io_issue_sqe(struct io_kiocb *req, bool force_nonblock,
struct io_comp_state *cs)
{
struct io_ring_ctx *ctx = req->ctx;
int ret;
switch (req->opcode) {
case IORING_OP_NOP:
ret = io_nop(req, cs);
break;
case IORING_OP_READV:
case IORING_OP_READ_FIXED:
case IORING_OP_READ:
ret = io_read(req, force_nonblock, cs);
break;
case IORING_OP_WRITEV:
case IORING_OP_WRITE_FIXED:
case IORING_OP_WRITE:
ret = io_write(req, force_nonblock, cs);
break;
case IORING_OP_FSYNC:
ret = io_fsync(req, force_nonblock);
break;
case IORING_OP_POLL_ADD:
ret = io_poll_add(req);
break;
case IORING_OP_POLL_REMOVE:
ret = io_poll_remove(req);
break;
case IORING_OP_SYNC_FILE_RANGE:
ret = io_sync_file_range(req, force_nonblock);
break;
case IORING_OP_SENDMSG:
ret = io_sendmsg(req, force_nonblock, cs);
break;
case IORING_OP_SEND:
ret = io_send(req, force_nonblock, cs);
break;
case IORING_OP_RECVMSG:
ret = io_recvmsg(req, force_nonblock, cs);
break;
case IORING_OP_RECV:
ret = io_recv(req, force_nonblock, cs);
break;
case IORING_OP_TIMEOUT:
ret = io_timeout(req);
break;
case IORING_OP_TIMEOUT_REMOVE:
ret = io_timeout_remove(req);
break;
case IORING_OP_ACCEPT:
ret = io_accept(req, force_nonblock, cs);
break;
case IORING_OP_CONNECT:
ret = io_connect(req, force_nonblock, cs);
break;
case IORING_OP_ASYNC_CANCEL:
ret = io_async_cancel(req);
break;
case IORING_OP_FALLOCATE:
ret = io_fallocate(req, force_nonblock);
break;
case IORING_OP_OPENAT:
ret = io_openat(req, force_nonblock);
break;
case IORING_OP_CLOSE:
ret = io_close(req, force_nonblock, cs);
break;
case IORING_OP_FILES_UPDATE:
ret = io_files_update(req, force_nonblock, cs);
break;
case IORING_OP_STATX:
ret = io_statx(req, force_nonblock);
break;
case IORING_OP_FADVISE:
ret = io_fadvise(req, force_nonblock);
break;
case IORING_OP_MADVISE:
ret = io_madvise(req, force_nonblock);
break;
case IORING_OP_OPENAT2:
ret = io_openat2(req, force_nonblock);
break;
case IORING_OP_EPOLL_CTL:
ret = io_epoll_ctl(req, force_nonblock, cs);
break;
case IORING_OP_SPLICE:
ret = io_splice(req, force_nonblock);
break;
case IORING_OP_PROVIDE_BUFFERS:
ret = io_provide_buffers(req, force_nonblock, cs);
break;
case IORING_OP_REMOVE_BUFFERS:
ret = io_remove_buffers(req, force_nonblock, cs);
break;
case IORING_OP_TEE:
ret = io_tee(req, force_nonblock);
break;
default:
ret = -EINVAL;
break;
}
if (ret)
return ret;
/* If the op doesn't have a file, we're not polling for it */
if ((ctx->flags & IORING_SETUP_IOPOLL) && req->file) {
const bool in_async = io_wq_current_is_worker();
/* workqueue context doesn't hold uring_lock, grab it now */
if (in_async)
mutex_lock(&ctx->uring_lock);
io_iopoll_req_issued(req);
if (in_async)
mutex_unlock(&ctx->uring_lock);
}
return 0;
}
static struct io_wq_work *io_wq_submit_work(struct io_wq_work *work)
{
struct io_kiocb *req = container_of(work, struct io_kiocb, work);
struct io_kiocb *timeout;
int ret = 0;
timeout = io_prep_linked_timeout(req);
if (timeout)
io_queue_linked_timeout(timeout);
/* if NO_CANCEL is set, we must still run the work */
if ((work->flags & (IO_WQ_WORK_CANCEL|IO_WQ_WORK_NO_CANCEL)) ==
IO_WQ_WORK_CANCEL) {
ret = -ECANCELED;
}
if (!ret) {
do {
ret = io_issue_sqe(req, false, NULL);
/*
* We can get EAGAIN for polled IO even though we're
* forcing a sync submission from here, since we can't
* wait for request slots on the block side.
*/
if (ret != -EAGAIN)
break;
cond_resched();
} while (1);
}
if (ret) {
req_set_fail_links(req);
io_req_complete(req, ret);
}
return io_steal_work(req);
}
static inline struct file *io_file_from_index(struct io_ring_ctx *ctx,
int index)
{
struct fixed_file_table *table;
table = &ctx->file_data->table[index >> IORING_FILE_TABLE_SHIFT];
return table->files[index & IORING_FILE_TABLE_MASK];
}
static struct file *io_file_get(struct io_submit_state *state,
struct io_kiocb *req, int fd, bool fixed)
{
struct io_ring_ctx *ctx = req->ctx;
struct file *file;
if (fixed) {
if (unlikely((unsigned int)fd >= ctx->nr_user_files))
return NULL;
fd = array_index_nospec(fd, ctx->nr_user_files);
file = io_file_from_index(ctx, fd);
if (file) {
req->fixed_file_refs = &ctx->file_data->node->refs;
percpu_ref_get(req->fixed_file_refs);
}
} else {
trace_io_uring_file_get(ctx, fd);
file = __io_file_get(state, fd);
}
return file;
}
static int io_req_set_file(struct io_submit_state *state, struct io_kiocb *req,
int fd)
{
bool fixed;
fixed = (req->flags & REQ_F_FIXED_FILE) != 0;
if (unlikely(!fixed && io_async_submit(req->ctx)))
return -EBADF;
req->file = io_file_get(state, req, fd, fixed);
if (req->file || io_op_defs[req->opcode].needs_file_no_error)
return 0;
return -EBADF;
}
static enum hrtimer_restart io_link_timeout_fn(struct hrtimer *timer)
{
struct io_timeout_data *data = container_of(timer,
struct io_timeout_data, timer);
struct io_kiocb *req = data->req;
struct io_ring_ctx *ctx = req->ctx;
struct io_kiocb *prev = NULL;
unsigned long flags;
spin_lock_irqsave(&ctx->completion_lock, flags);
/*
* We don't expect the list to be empty, that will only happen if we
* race with the completion of the linked work.
*/
if (!list_empty(&req->link_list)) {
prev = list_entry(req->link_list.prev, struct io_kiocb,
link_list);
if (refcount_inc_not_zero(&prev->refs))
list_del_init(&req->link_list);
else
prev = NULL;
}
spin_unlock_irqrestore(&ctx->completion_lock, flags);
if (prev) {
req_set_fail_links(prev);
io_async_find_and_cancel(ctx, req, prev->user_data, -ETIME);
io_put_req(prev);
} else {
io_req_complete(req, -ETIME);
}
return HRTIMER_NORESTART;
}
static void __io_queue_linked_timeout(struct io_kiocb *req)
{
/*
* If the list is now empty, then our linked request finished before
* we got a chance to setup the timer
*/
if (!list_empty(&req->link_list)) {
struct io_timeout_data *data = req->async_data;
data->timer.function = io_link_timeout_fn;
hrtimer_start(&data->timer, timespec64_to_ktime(data->ts),
data->mode);
}
}
static void io_queue_linked_timeout(struct io_kiocb *req)
{
struct io_ring_ctx *ctx = req->ctx;
spin_lock_irq(&ctx->completion_lock);
__io_queue_linked_timeout(req);
spin_unlock_irq(&ctx->completion_lock);
/* drop submission reference */
io_put_req(req);
}
static struct io_kiocb *io_prep_linked_timeout(struct io_kiocb *req)
{
struct io_kiocb *nxt;
if (!(req->flags & REQ_F_LINK_HEAD))
return NULL;
if (req->flags & REQ_F_LINK_TIMEOUT)
return NULL;
nxt = list_first_entry_or_null(&req->link_list, struct io_kiocb,
link_list);
if (!nxt || nxt->opcode != IORING_OP_LINK_TIMEOUT)
return NULL;
nxt->flags |= REQ_F_LTIMEOUT_ACTIVE;
req->flags |= REQ_F_LINK_TIMEOUT;
return nxt;
}
static void __io_queue_sqe(struct io_kiocb *req, struct io_comp_state *cs)
{
struct io_kiocb *linked_timeout;
const struct cred *old_creds = NULL;
int ret;
again:
linked_timeout = io_prep_linked_timeout(req);
if ((req->flags & REQ_F_WORK_INITIALIZED) &&
(req->work.flags & IO_WQ_WORK_CREDS) &&
req->work.identity->creds != current_cred()) {
if (old_creds)
revert_creds(old_creds);
if (old_creds == req->work.identity->creds)
old_creds = NULL; /* restored original creds */
else
old_creds = override_creds(req->work.identity->creds);
}
ret = io_issue_sqe(req, true, cs);
/*
* We async punt it if the file wasn't marked NOWAIT, or if the file
* doesn't support non-blocking read/write attempts
*/
if (ret == -EAGAIN && !(req->flags & REQ_F_NOWAIT)) {
if (!io_arm_poll_handler(req)) {
/*
* Queued up for async execution, worker will release
* submit reference when the iocb is actually submitted.
*/
io_queue_async_work(req);
}
if (linked_timeout)
io_queue_linked_timeout(linked_timeout);
} else if (likely(!ret)) {
/* drop submission reference */
req = io_put_req_find_next(req);
if (linked_timeout)
io_queue_linked_timeout(linked_timeout);
if (req) {
if (!(req->flags & REQ_F_FORCE_ASYNC))
goto again;
io_queue_async_work(req);
}
} else {
/* un-prep timeout, so it'll be killed as any other linked */
req->flags &= ~REQ_F_LINK_TIMEOUT;
req_set_fail_links(req);
io_put_req(req);
io_req_complete(req, ret);
}
if (old_creds)
revert_creds(old_creds);
}
static void io_queue_sqe(struct io_kiocb *req, const struct io_uring_sqe *sqe,
struct io_comp_state *cs)
{
int ret;
ret = io_req_defer(req, sqe);
if (ret) {
if (ret != -EIOCBQUEUED) {
fail_req:
req_set_fail_links(req);
io_put_req(req);
io_req_complete(req, ret);
}
} else if (req->flags & REQ_F_FORCE_ASYNC) {
if (!req->async_data) {
ret = io_req_defer_prep(req, sqe);
if (unlikely(ret))
goto fail_req;
}
io_queue_async_work(req);
} else {
if (sqe) {
ret = io_req_prep(req, sqe);
if (unlikely(ret))
goto fail_req;
}
__io_queue_sqe(req, cs);
}
}
static inline void io_queue_link_head(struct io_kiocb *req,
struct io_comp_state *cs)
{
if (unlikely(req->flags & REQ_F_FAIL_LINK)) {
io_put_req(req);
io_req_complete(req, -ECANCELED);
} else
io_queue_sqe(req, NULL, cs);
}
static int io_submit_sqe(struct io_kiocb *req, const struct io_uring_sqe *sqe,
struct io_kiocb **link, struct io_comp_state *cs)
{
struct io_ring_ctx *ctx = req->ctx;
int ret;
/*
* If we already have a head request, queue this one for async
* submittal once the head completes. If we don't have a head but
* IOSQE_IO_LINK is set in the sqe, start a new head. This one will be
* submitted sync once the chain is complete. If none of those
* conditions are true (normal request), then just queue it.
*/
if (*link) {
struct io_kiocb *head = *link;
/*
* Taking sequential execution of a link, draining both sides
* of the link also fullfils IOSQE_IO_DRAIN semantics for all
* requests in the link. So, it drains the head and the
* next after the link request. The last one is done via
* drain_next flag to persist the effect across calls.
*/
if (req->flags & REQ_F_IO_DRAIN) {
head->flags |= REQ_F_IO_DRAIN;
ctx->drain_next = 1;
}
ret = io_req_defer_prep(req, sqe);
if (unlikely(ret)) {
/* fail even hard links since we don't submit */
head->flags |= REQ_F_FAIL_LINK;
return ret;
}
trace_io_uring_link(ctx, req, head);
list_add_tail(&req->link_list, &head->link_list);
/* last request of a link, enqueue the link */
if (!(req->flags & (REQ_F_LINK | REQ_F_HARDLINK))) {
io_queue_link_head(head, cs);
*link = NULL;
}
} else {
if (unlikely(ctx->drain_next)) {
req->flags |= REQ_F_IO_DRAIN;
ctx->drain_next = 0;
}
if (req->flags & (REQ_F_LINK | REQ_F_HARDLINK)) {
req->flags |= REQ_F_LINK_HEAD;
INIT_LIST_HEAD(&req->link_list);
ret = io_req_defer_prep(req, sqe);
if (unlikely(ret))
req->flags |= REQ_F_FAIL_LINK;
*link = req;
} else {
io_queue_sqe(req, sqe, cs);
}
}
return 0;
}
/*
* Batched submission is done, ensure local IO is flushed out.
*/
static void io_submit_state_end(struct io_submit_state *state)
{
if (!list_empty(&state->comp.list))
io_submit_flush_completions(&state->comp);
blk_finish_plug(&state->plug);
io_state_file_put(state);
if (state->free_reqs)
kmem_cache_free_bulk(req_cachep, state->free_reqs, state->reqs);
}
/*
* Start submission side cache.
*/
static void io_submit_state_start(struct io_submit_state *state,
struct io_ring_ctx *ctx, unsigned int max_ios)
{
blk_start_plug(&state->plug);
state->comp.nr = 0;
INIT_LIST_HEAD(&state->comp.list);
state->comp.ctx = ctx;
state->free_reqs = 0;
state->file = NULL;
state->ios_left = max_ios;
}
static void io_commit_sqring(struct io_ring_ctx *ctx)
{
struct io_rings *rings = ctx->rings;
/*
* Ensure any loads from the SQEs are done at this point,
* since once we write the new head, the application could
* write new data to them.
*/
smp_store_release(&rings->sq.head, ctx->cached_sq_head);
}
/*
* Fetch an sqe, if one is available. Note that sqe_ptr will point to memory
* that is mapped by userspace. This means that care needs to be taken to
* ensure that reads are stable, as we cannot rely on userspace always
* being a good citizen. If members of the sqe are validated and then later
* used, it's important that those reads are done through READ_ONCE() to
* prevent a re-load down the line.
*/
static const struct io_uring_sqe *io_get_sqe(struct io_ring_ctx *ctx)
{
u32 *sq_array = ctx->sq_array;
unsigned head;
/*
* The cached sq head (or cq tail) serves two purposes:
*
* 1) allows us to batch the cost of updating the user visible
* head updates.
* 2) allows the kernel side to track the head on its own, even
* though the application is the one updating it.
*/
head = READ_ONCE(sq_array[ctx->cached_sq_head & ctx->sq_mask]);
if (likely(head < ctx->sq_entries))
return &ctx->sq_sqes[head];
/* drop invalid entries */
ctx->cached_sq_dropped++;
WRITE_ONCE(ctx->rings->sq_dropped, ctx->cached_sq_dropped);
return NULL;
}
static inline void io_consume_sqe(struct io_ring_ctx *ctx)
{
ctx->cached_sq_head++;
}
/*
* Check SQE restrictions (opcode and flags).
*
* Returns 'true' if SQE is allowed, 'false' otherwise.
*/
static inline bool io_check_restriction(struct io_ring_ctx *ctx,
struct io_kiocb *req,
unsigned int sqe_flags)
{
if (!ctx->restricted)
return true;
if (!test_bit(req->opcode, ctx->restrictions.sqe_op))
return false;
if ((sqe_flags & ctx->restrictions.sqe_flags_required) !=
ctx->restrictions.sqe_flags_required)
return false;
if (sqe_flags & ~(ctx->restrictions.sqe_flags_allowed |
ctx->restrictions.sqe_flags_required))
return false;
return true;
}
#define SQE_VALID_FLAGS (IOSQE_FIXED_FILE|IOSQE_IO_DRAIN|IOSQE_IO_LINK| \
IOSQE_IO_HARDLINK | IOSQE_ASYNC | \
IOSQE_BUFFER_SELECT)
static int io_init_req(struct io_ring_ctx *ctx, struct io_kiocb *req,
const struct io_uring_sqe *sqe,
struct io_submit_state *state)
{
unsigned int sqe_flags;
int id, ret;
req->opcode = READ_ONCE(sqe->opcode);
req->user_data = READ_ONCE(sqe->user_data);
req->async_data = NULL;
req->file = NULL;
req->ctx = ctx;
req->flags = 0;
/* one is dropped after submission, the other at completion */
refcount_set(&req->refs, 2);
req->task = current;
req->result = 0;
if (unlikely(req->opcode >= IORING_OP_LAST))
return -EINVAL;
if (unlikely(io_sq_thread_acquire_mm(ctx, req)))
return -EFAULT;
sqe_flags = READ_ONCE(sqe->flags);
/* enforce forwards compatibility on users */
if (unlikely(sqe_flags & ~SQE_VALID_FLAGS))
return -EINVAL;
if (unlikely(!io_check_restriction(ctx, req, sqe_flags)))
return -EACCES;
if ((sqe_flags & IOSQE_BUFFER_SELECT) &&
!io_op_defs[req->opcode].buffer_select)
return -EOPNOTSUPP;
id = READ_ONCE(sqe->personality);
if (id) {
struct io_identity *iod;
iod = idr_find(&ctx->personality_idr, id);
if (unlikely(!iod))
return -EINVAL;
refcount_inc(&iod->count);
__io_req_init_async(req);
get_cred(iod->creds);
req->work.identity = iod;
req->work.flags |= IO_WQ_WORK_CREDS;
}
/* same numerical values with corresponding REQ_F_*, safe to copy */
req->flags |= sqe_flags;
if (!io_op_defs[req->opcode].needs_file)
return 0;
ret = io_req_set_file(state, req, READ_ONCE(sqe->fd));
state->ios_left--;
return ret;
}
static int io_submit_sqes(struct io_ring_ctx *ctx, unsigned int nr)
{
struct io_submit_state state;
struct io_kiocb *link = NULL;
int i, submitted = 0;
/* if we have a backlog and couldn't flush it all, return BUSY */
if (test_bit(0, &ctx->sq_check_overflow)) {
if (!list_empty(&ctx->cq_overflow_list) &&
!io_cqring_overflow_flush(ctx, false, NULL, NULL))
return -EBUSY;
}
/* make sure SQ entry isn't read before tail */
nr = min3(nr, ctx->sq_entries, io_sqring_entries(ctx));
if (!percpu_ref_tryget_many(&ctx->refs, nr))
return -EAGAIN;
percpu_counter_add(&current->io_uring->inflight, nr);
refcount_add(nr, &current->usage);
io_submit_state_start(&state, ctx, nr);
for (i = 0; i < nr; i++) {
const struct io_uring_sqe *sqe;
struct io_kiocb *req;
int err;
sqe = io_get_sqe(ctx);
if (unlikely(!sqe)) {
io_consume_sqe(ctx);
break;
}
req = io_alloc_req(ctx, &state);
if (unlikely(!req)) {
if (!submitted)
submitted = -EAGAIN;
break;
}
io_consume_sqe(ctx);
/* will complete beyond this point, count as submitted */
submitted++;
err = io_init_req(ctx, req, sqe, &state);
if (unlikely(err)) {
fail_req:
io_put_req(req);
io_req_complete(req, err);
break;
}
trace_io_uring_submit_sqe(ctx, req->opcode, req->user_data,
true, io_async_submit(ctx));
err = io_submit_sqe(req, sqe, &link, &state.comp);
if (err)
goto fail_req;
}
if (unlikely(submitted != nr)) {
int ref_used = (submitted == -EAGAIN) ? 0 : submitted;
struct io_uring_task *tctx = current->io_uring;
int unused = nr - ref_used;
percpu_ref_put_many(&ctx->refs, unused);
percpu_counter_sub(&tctx->inflight, unused);
put_task_struct_many(current, unused);
}
if (link)
io_queue_link_head(link, &state.comp);
io_submit_state_end(&state);
/* Commit SQ ring head once we've consumed and submitted all SQEs */
io_commit_sqring(ctx);
return submitted;
}
static inline void io_ring_set_wakeup_flag(struct io_ring_ctx *ctx)
{
/* Tell userspace we may need a wakeup call */
spin_lock_irq(&ctx->completion_lock);
ctx->rings->sq_flags |= IORING_SQ_NEED_WAKEUP;
spin_unlock_irq(&ctx->completion_lock);
}
static inline void io_ring_clear_wakeup_flag(struct io_ring_ctx *ctx)
{
spin_lock_irq(&ctx->completion_lock);
ctx->rings->sq_flags &= ~IORING_SQ_NEED_WAKEUP;
spin_unlock_irq(&ctx->completion_lock);
}
static int io_sq_wake_function(struct wait_queue_entry *wqe, unsigned mode,
int sync, void *key)
{
struct io_ring_ctx *ctx = container_of(wqe, struct io_ring_ctx, sqo_wait_entry);
int ret;
ret = autoremove_wake_function(wqe, mode, sync, key);
if (ret) {
unsigned long flags;
spin_lock_irqsave(&ctx->completion_lock, flags);
ctx->rings->sq_flags &= ~IORING_SQ_NEED_WAKEUP;
spin_unlock_irqrestore(&ctx->completion_lock, flags);
}
return ret;
}
enum sq_ret {
SQT_IDLE = 1,
SQT_SPIN = 2,
SQT_DID_WORK = 4,
};
static enum sq_ret __io_sq_thread(struct io_ring_ctx *ctx,
unsigned long start_jiffies, bool cap_entries)
{
unsigned long timeout = start_jiffies + ctx->sq_thread_idle;
struct io_sq_data *sqd = ctx->sq_data;
unsigned int to_submit;
int ret = 0;
again:
if (!list_empty(&ctx->iopoll_list)) {
unsigned nr_events = 0;
mutex_lock(&ctx->uring_lock);
if (!list_empty(&ctx->iopoll_list) && !need_resched())
io_do_iopoll(ctx, &nr_events, 0);
mutex_unlock(&ctx->uring_lock);
}
to_submit = io_sqring_entries(ctx);
/*
* If submit got -EBUSY, flag us as needing the application
* to enter the kernel to reap and flush events.
*/
if (!to_submit || ret == -EBUSY || need_resched()) {
/*
* Drop cur_mm before scheduling, we can't hold it for
* long periods (or over schedule()). Do this before
* adding ourselves to the waitqueue, as the unuse/drop
* may sleep.
*/
io_sq_thread_drop_mm();
/*
* We're polling. If we're within the defined idle
* period, then let us spin without work before going
* to sleep. The exception is if we got EBUSY doing
* more IO, we should wait for the application to
* reap events and wake us up.
*/
if (!list_empty(&ctx->iopoll_list) || need_resched() ||
(!time_after(jiffies, timeout) && ret != -EBUSY &&
!percpu_ref_is_dying(&ctx->refs)))
return SQT_SPIN;
prepare_to_wait(&sqd->wait, &ctx->sqo_wait_entry,
TASK_INTERRUPTIBLE);
/*
* While doing polled IO, before going to sleep, we need
* to check if there are new reqs added to iopoll_list,
* it is because reqs may have been punted to io worker
* and will be added to iopoll_list later, hence check
* the iopoll_list again.
*/
if ((ctx->flags & IORING_SETUP_IOPOLL) &&
!list_empty_careful(&ctx->iopoll_list)) {
finish_wait(&sqd->wait, &ctx->sqo_wait_entry);
goto again;
}
to_submit = io_sqring_entries(ctx);
if (!to_submit || ret == -EBUSY)
return SQT_IDLE;
}
finish_wait(&sqd->wait, &ctx->sqo_wait_entry);
io_ring_clear_wakeup_flag(ctx);
/* if we're handling multiple rings, cap submit size for fairness */
if (cap_entries && to_submit > 8)
to_submit = 8;
mutex_lock(&ctx->uring_lock);
if (likely(!percpu_ref_is_dying(&ctx->refs)))
ret = io_submit_sqes(ctx, to_submit);
mutex_unlock(&ctx->uring_lock);
if (!io_sqring_full(ctx) && wq_has_sleeper(&ctx->sqo_sq_wait))
wake_up(&ctx->sqo_sq_wait);
return SQT_DID_WORK;
}
static void io_sqd_init_new(struct io_sq_data *sqd)
{
struct io_ring_ctx *ctx;
while (!list_empty(&sqd->ctx_new_list)) {
ctx = list_first_entry(&sqd->ctx_new_list, struct io_ring_ctx, sqd_list);
init_wait(&ctx->sqo_wait_entry);
ctx->sqo_wait_entry.func = io_sq_wake_function;
list_move_tail(&ctx->sqd_list, &sqd->ctx_list);
complete(&ctx->sq_thread_comp);
}
}
static int io_sq_thread(void *data)
{
struct cgroup_subsys_state *cur_css = NULL;
const struct cred *old_cred = NULL;
struct io_sq_data *sqd = data;
struct io_ring_ctx *ctx;
unsigned long start_jiffies;
start_jiffies = jiffies;
while (!kthread_should_stop()) {
enum sq_ret ret = 0;
bool cap_entries;
/*
* Any changes to the sqd lists are synchronized through the
* kthread parking. This synchronizes the thread vs users,
* the users are synchronized on the sqd->ctx_lock.
*/
if (kthread_should_park())
kthread_parkme();
if (unlikely(!list_empty(&sqd->ctx_new_list)))
io_sqd_init_new(sqd);
cap_entries = !list_is_singular(&sqd->ctx_list);
list_for_each_entry(ctx, &sqd->ctx_list, sqd_list) {
if (current->cred != ctx->creds) {
if (old_cred)
revert_creds(old_cred);
old_cred = override_creds(ctx->creds);
}
io_sq_thread_associate_blkcg(ctx, &cur_css);
#ifdef CONFIG_AUDIT
current->loginuid = ctx->loginuid;
current->sessionid = ctx->sessionid;
#endif
ret |= __io_sq_thread(ctx, start_jiffies, cap_entries);
io_sq_thread_drop_mm();
}
if (ret & SQT_SPIN) {
io_run_task_work();
cond_resched();
} else if (ret == SQT_IDLE) {
if (kthread_should_park())
continue;
list_for_each_entry(ctx, &sqd->ctx_list, sqd_list)
io_ring_set_wakeup_flag(ctx);
schedule();
start_jiffies = jiffies;
list_for_each_entry(ctx, &sqd->ctx_list, sqd_list)
io_ring_clear_wakeup_flag(ctx);
}
}
io_run_task_work();
if (cur_css)
io_sq_thread_unassociate_blkcg();
if (old_cred)
revert_creds(old_cred);
kthread_parkme();
return 0;
}
struct io_wait_queue {
struct wait_queue_entry wq;
struct io_ring_ctx *ctx;
unsigned to_wait;
unsigned nr_timeouts;
};
static inline bool io_should_wake(struct io_wait_queue *iowq, bool noflush)
{
struct io_ring_ctx *ctx = iowq->ctx;
/*
* Wake up if we have enough events, or if a timeout occurred since we
* started waiting. For timeouts, we always want to return to userspace,
* regardless of event count.
*/
return io_cqring_events(ctx, noflush) >= iowq->to_wait ||
atomic_read(&ctx->cq_timeouts) != iowq->nr_timeouts;
}
static int io_wake_function(struct wait_queue_entry *curr, unsigned int mode,
int wake_flags, void *key)
{
struct io_wait_queue *iowq = container_of(curr, struct io_wait_queue,
wq);
/* use noflush == true, as we can't safely rely on locking context */
if (!io_should_wake(iowq, true))
return -1;
return autoremove_wake_function(curr, mode, wake_flags, key);
}
static int io_run_task_work_sig(void)
{
if (io_run_task_work())
return 1;
if (!signal_pending(current))
return 0;
if (current->jobctl & JOBCTL_TASK_WORK) {
spin_lock_irq(&current->sighand->siglock);
current->jobctl &= ~JOBCTL_TASK_WORK;
recalc_sigpending();
spin_unlock_irq(&current->sighand->siglock);
return 1;
}
return -EINTR;
}
/*
* Wait until events become available, if we don't already have some. The
* application must reap them itself, as they reside on the shared cq ring.
*/
static int io_cqring_wait(struct io_ring_ctx *ctx, int min_events,
const sigset_t __user *sig, size_t sigsz)
{
struct io_wait_queue iowq = {
.wq = {
.private = current,
.func = io_wake_function,
.entry = LIST_HEAD_INIT(iowq.wq.entry),
},
.ctx = ctx,
.to_wait = min_events,
};
struct io_rings *rings = ctx->rings;
int ret = 0;
do {
if (io_cqring_events(ctx, false) >= min_events)
return 0;
if (!io_run_task_work())
break;
} while (1);
if (sig) {
#ifdef CONFIG_COMPAT
if (in_compat_syscall())
ret = set_compat_user_sigmask((const compat_sigset_t __user *)sig,
sigsz);
else
#endif
ret = set_user_sigmask(sig, sigsz);
if (ret)
return ret;
}
iowq.nr_timeouts = atomic_read(&ctx->cq_timeouts);
trace_io_uring_cqring_wait(ctx, min_events);
do {
prepare_to_wait_exclusive(&ctx->wait, &iowq.wq,
TASK_INTERRUPTIBLE);
/* make sure we run task_work before checking for signals */
ret = io_run_task_work_sig();
if (ret > 0)
continue;
else if (ret < 0)
break;
if (io_should_wake(&iowq, false))
break;
schedule();
} while (1);
finish_wait(&ctx->wait, &iowq.wq);
restore_saved_sigmask_unless(ret == -EINTR);
return READ_ONCE(rings->cq.head) == READ_ONCE(rings->cq.tail) ? ret : 0;
}
static void __io_sqe_files_unregister(struct io_ring_ctx *ctx)
{
#if defined(CONFIG_UNIX)
if (ctx->ring_sock) {
struct sock *sock = ctx->ring_sock->sk;
struct sk_buff *skb;
while ((skb = skb_dequeue(&sock->sk_receive_queue)) != NULL)
kfree_skb(skb);
}
#else
int i;
for (i = 0; i < ctx->nr_user_files; i++) {
struct file *file;
file = io_file_from_index(ctx, i);
if (file)
fput(file);
}
#endif
}
static void io_file_ref_kill(struct percpu_ref *ref)
{
struct fixed_file_data *data;
data = container_of(ref, struct fixed_file_data, refs);
complete(&data->done);
}
static int io_sqe_files_unregister(struct io_ring_ctx *ctx)
{
struct fixed_file_data *data = ctx->file_data;
struct fixed_file_ref_node *ref_node = NULL;
unsigned nr_tables, i;
if (!data)
return -ENXIO;
spin_lock(&data->lock);
ref_node = data->node;
spin_unlock(&data->lock);
if (ref_node)
percpu_ref_kill(&ref_node->refs);
percpu_ref_kill(&data->refs);
/* wait for all refs nodes to complete */
flush_delayed_work(&ctx->file_put_work);
wait_for_completion(&data->done);
__io_sqe_files_unregister(ctx);
nr_tables = DIV_ROUND_UP(ctx->nr_user_files, IORING_MAX_FILES_TABLE);
for (i = 0; i < nr_tables; i++)
kfree(data->table[i].files);
kfree(data->table);
percpu_ref_exit(&data->refs);
kfree(data);
ctx->file_data = NULL;
ctx->nr_user_files = 0;
return 0;
}
static void io_put_sq_data(struct io_sq_data *sqd)
{
if (refcount_dec_and_test(&sqd->refs)) {
/*
* The park is a bit of a work-around, without it we get
* warning spews on shutdown with SQPOLL set and affinity
* set to a single CPU.
*/
if (sqd->thread) {
kthread_park(sqd->thread);
kthread_stop(sqd->thread);
}
kfree(sqd);
}
}
static struct io_sq_data *io_attach_sq_data(struct io_uring_params *p)
{
struct io_ring_ctx *ctx_attach;
struct io_sq_data *sqd;
struct fd f;
f = fdget(p->wq_fd);
if (!f.file)
return ERR_PTR(-ENXIO);
if (f.file->f_op != &io_uring_fops) {
fdput(f);
return ERR_PTR(-EINVAL);
}
ctx_attach = f.file->private_data;
sqd = ctx_attach->sq_data;
if (!sqd) {
fdput(f);
return ERR_PTR(-EINVAL);
}
refcount_inc(&sqd->refs);
fdput(f);
return sqd;
}
static struct io_sq_data *io_get_sq_data(struct io_uring_params *p)
{
struct io_sq_data *sqd;
if (p->flags & IORING_SETUP_ATTACH_WQ)
return io_attach_sq_data(p);
sqd = kzalloc(sizeof(*sqd), GFP_KERNEL);
if (!sqd)
return ERR_PTR(-ENOMEM);
refcount_set(&sqd->refs, 1);
INIT_LIST_HEAD(&sqd->ctx_list);
INIT_LIST_HEAD(&sqd->ctx_new_list);
mutex_init(&sqd->ctx_lock);
mutex_init(&sqd->lock);
init_waitqueue_head(&sqd->wait);
return sqd;
}
static void io_sq_thread_unpark(struct io_sq_data *sqd)
__releases(&sqd->lock)
{
if (!sqd->thread)
return;
kthread_unpark(sqd->thread);
mutex_unlock(&sqd->lock);
}
static void io_sq_thread_park(struct io_sq_data *sqd)
__acquires(&sqd->lock)
{
if (!sqd->thread)
return;
mutex_lock(&sqd->lock);
kthread_park(sqd->thread);
}
static void io_sq_thread_stop(struct io_ring_ctx *ctx)
{
struct io_sq_data *sqd = ctx->sq_data;
if (sqd) {
if (sqd->thread) {
/*
* We may arrive here from the error branch in
* io_sq_offload_create() where the kthread is created
* without being waked up, thus wake it up now to make
* sure the wait will complete.
*/
wake_up_process(sqd->thread);
wait_for_completion(&ctx->sq_thread_comp);
io_sq_thread_park(sqd);
}
mutex_lock(&sqd->ctx_lock);
list_del(&ctx->sqd_list);
mutex_unlock(&sqd->ctx_lock);
if (sqd->thread) {
finish_wait(&sqd->wait, &ctx->sqo_wait_entry);
io_sq_thread_unpark(sqd);
}
io_put_sq_data(sqd);
ctx->sq_data = NULL;
}
}
static void io_finish_async(struct io_ring_ctx *ctx)
{
io_sq_thread_stop(ctx);
if (ctx->io_wq) {
io_wq_destroy(ctx->io_wq);
ctx->io_wq = NULL;
}
}
#if defined(CONFIG_UNIX)
/*
* Ensure the UNIX gc is aware of our file set, so we are certain that
* the io_uring can be safely unregistered on process exit, even if we have
* loops in the file referencing.
*/
static int __io_sqe_files_scm(struct io_ring_ctx *ctx, int nr, int offset)
{
struct sock *sk = ctx->ring_sock->sk;
struct scm_fp_list *fpl;
struct sk_buff *skb;
int i, nr_files;
fpl = kzalloc(sizeof(*fpl), GFP_KERNEL);
if (!fpl)
return -ENOMEM;
skb = alloc_skb(0, GFP_KERNEL);
if (!skb) {
kfree(fpl);
return -ENOMEM;
}
skb->sk = sk;
nr_files = 0;
fpl->user = get_uid(ctx->user);
for (i = 0; i < nr; i++) {
struct file *file = io_file_from_index(ctx, i + offset);
if (!file)
continue;
fpl->fp[nr_files] = get_file(file);
unix_inflight(fpl->user, fpl->fp[nr_files]);
nr_files++;
}
if (nr_files) {
fpl->max = SCM_MAX_FD;
fpl->count = nr_files;
UNIXCB(skb).fp = fpl;
skb->destructor = unix_destruct_scm;
refcount_add(skb->truesize, &sk->sk_wmem_alloc);
skb_queue_head(&sk->sk_receive_queue, skb);
for (i = 0; i < nr_files; i++)
fput(fpl->fp[i]);
} else {
kfree_skb(skb);
kfree(fpl);
}
return 0;
}
/*
* If UNIX sockets are enabled, fd passing can cause a reference cycle which
* causes regular reference counting to break down. We rely on the UNIX
* garbage collection to take care of this problem for us.
*/
static int io_sqe_files_scm(struct io_ring_ctx *ctx)
{
unsigned left, total;
int ret = 0;
total = 0;
left = ctx->nr_user_files;
while (left) {
unsigned this_files = min_t(unsigned, left, SCM_MAX_FD);
ret = __io_sqe_files_scm(ctx, this_files, total);
if (ret)
break;
left -= this_files;
total += this_files;
}
if (!ret)
return 0;
while (total < ctx->nr_user_files) {
struct file *file = io_file_from_index(ctx, total);
if (file)
fput(file);
total++;
}
return ret;
}
#else
static int io_sqe_files_scm(struct io_ring_ctx *ctx)
{
return 0;
}
#endif
static int io_sqe_alloc_file_tables(struct fixed_file_data *file_data,
unsigned nr_tables, unsigned nr_files)
{
int i;
for (i = 0; i < nr_tables; i++) {
struct fixed_file_table *table = &file_data->table[i];
unsigned this_files;
this_files = min(nr_files, IORING_MAX_FILES_TABLE);
table->files = kcalloc(this_files, sizeof(struct file *),
GFP_KERNEL);
if (!table->files)
break;
nr_files -= this_files;
}
if (i == nr_tables)
return 0;
for (i = 0; i < nr_tables; i++) {
struct fixed_file_table *table = &file_data->table[i];
kfree(table->files);
}
return 1;
}
static void io_ring_file_put(struct io_ring_ctx *ctx, struct file *file)
{
#if defined(CONFIG_UNIX)
struct sock *sock = ctx->ring_sock->sk;
struct sk_buff_head list, *head = &sock->sk_receive_queue;
struct sk_buff *skb;
int i;
__skb_queue_head_init(&list);
/*
* Find the skb that holds this file in its SCM_RIGHTS. When found,
* remove this entry and rearrange the file array.
*/
skb = skb_dequeue(head);
while (skb) {
struct scm_fp_list *fp;
fp = UNIXCB(skb).fp;
for (i = 0; i < fp->count; i++) {
int left;
if (fp->fp[i] != file)
continue;
unix_notinflight(fp->user, fp->fp[i]);
left = fp->count - 1 - i;
if (left) {
memmove(&fp->fp[i], &fp->fp[i + 1],
left * sizeof(struct file *));
}
fp->count--;
if (!fp->count) {
kfree_skb(skb);
skb = NULL;
} else {
__skb_queue_tail(&list, skb);
}
fput(file);
file = NULL;
break;
}
if (!file)
break;
__skb_queue_tail(&list, skb);
skb = skb_dequeue(head);
}
if (skb_peek(&list)) {
spin_lock_irq(&head->lock);
while ((skb = __skb_dequeue(&list)) != NULL)
__skb_queue_tail(head, skb);
spin_unlock_irq(&head->lock);
}
#else
fput(file);
#endif
}
struct io_file_put {
struct list_head list;
struct file *file;
};
static void __io_file_put_work(struct fixed_file_ref_node *ref_node)
{
struct fixed_file_data *file_data = ref_node->file_data;
struct io_ring_ctx *ctx = file_data->ctx;
struct io_file_put *pfile, *tmp;
list_for_each_entry_safe(pfile, tmp, &ref_node->file_list, list) {
list_del(&pfile->list);
io_ring_file_put(ctx, pfile->file);
kfree(pfile);
}
percpu_ref_exit(&ref_node->refs);
kfree(ref_node);
percpu_ref_put(&file_data->refs);
}
static void io_file_put_work(struct work_struct *work)
{
struct io_ring_ctx *ctx;
struct llist_node *node;
ctx = container_of(work, struct io_ring_ctx, file_put_work.work);
node = llist_del_all(&ctx->file_put_llist);
while (node) {
struct fixed_file_ref_node *ref_node;
struct llist_node *next = node->next;
ref_node = llist_entry(node, struct fixed_file_ref_node, llist);
__io_file_put_work(ref_node);
node = next;
}
}
static void io_file_data_ref_zero(struct percpu_ref *ref)
{
struct fixed_file_ref_node *ref_node;
struct fixed_file_data *data;
struct io_ring_ctx *ctx;
bool first_add = false;
int delay = HZ;
ref_node = container_of(ref, struct fixed_file_ref_node, refs);
data = ref_node->file_data;
ctx = data->ctx;
spin_lock(&data->lock);
ref_node->done = true;
while (!list_empty(&data->ref_list)) {
ref_node = list_first_entry(&data->ref_list,
struct fixed_file_ref_node, node);
/* recycle ref nodes in order */
if (!ref_node->done)
break;
list_del(&ref_node->node);
first_add |= llist_add(&ref_node->llist, &ctx->file_put_llist);
}
spin_unlock(&data->lock);
if (percpu_ref_is_dying(&data->refs))
delay = 0;
if (!delay)
mod_delayed_work(system_wq, &ctx->file_put_work, 0);
else if (first_add)
queue_delayed_work(system_wq, &ctx->file_put_work, delay);
}
static struct fixed_file_ref_node *alloc_fixed_file_ref_node(
struct io_ring_ctx *ctx)
{
struct fixed_file_ref_node *ref_node;
ref_node = kzalloc(sizeof(*ref_node), GFP_KERNEL);
if (!ref_node)
return ERR_PTR(-ENOMEM);
if (percpu_ref_init(&ref_node->refs, io_file_data_ref_zero,
0, GFP_KERNEL)) {
kfree(ref_node);
return ERR_PTR(-ENOMEM);
}
INIT_LIST_HEAD(&ref_node->node);
INIT_LIST_HEAD(&ref_node->file_list);
ref_node->file_data = ctx->file_data;
ref_node->done = false;
return ref_node;
}
static void destroy_fixed_file_ref_node(struct fixed_file_ref_node *ref_node)
{
percpu_ref_exit(&ref_node->refs);
kfree(ref_node);
}
static int io_sqe_files_register(struct io_ring_ctx *ctx, void __user *arg,
unsigned nr_args)
{
__s32 __user *fds = (__s32 __user *) arg;
unsigned nr_tables, i;
struct file *file;
int fd, ret = -ENOMEM;
struct fixed_file_ref_node *ref_node;
struct fixed_file_data *file_data;
if (ctx->file_data)
return -EBUSY;
if (!nr_args)
return -EINVAL;
if (nr_args > IORING_MAX_FIXED_FILES)
return -EMFILE;
file_data = kzalloc(sizeof(*ctx->file_data), GFP_KERNEL);
if (!file_data)
return -ENOMEM;
file_data->ctx = ctx;
init_completion(&file_data->done);
INIT_LIST_HEAD(&file_data->ref_list);
spin_lock_init(&file_data->lock);
nr_tables = DIV_ROUND_UP(nr_args, IORING_MAX_FILES_TABLE);
file_data->table = kcalloc(nr_tables, sizeof(*file_data->table),
GFP_KERNEL);
if (!file_data->table)
goto out_free;
if (percpu_ref_init(&file_data->refs, io_file_ref_kill,
PERCPU_REF_ALLOW_REINIT, GFP_KERNEL))
goto out_free;
if (io_sqe_alloc_file_tables(file_data, nr_tables, nr_args))
goto out_ref;
ctx->file_data = file_data;
for (i = 0; i < nr_args; i++, ctx->nr_user_files++) {
struct fixed_file_table *table;
unsigned index;
if (copy_from_user(&fd, &fds[i], sizeof(fd))) {
ret = -EFAULT;
goto out_fput;
}
/* allow sparse sets */
if (fd == -1)
continue;
file = fget(fd);
ret = -EBADF;
if (!file)
goto out_fput;
/*
* Don't allow io_uring instances to be registered. If UNIX
* isn't enabled, then this causes a reference cycle and this
* instance can never get freed. If UNIX is enabled we'll
* handle it just fine, but there's still no point in allowing
* a ring fd as it doesn't support regular read/write anyway.
*/
if (file->f_op == &io_uring_fops) {
fput(file);
goto out_fput;
}
table = &file_data->table[i >> IORING_FILE_TABLE_SHIFT];
index = i & IORING_FILE_TABLE_MASK;
table->files[index] = file;
}
ret = io_sqe_files_scm(ctx);
if (ret) {
io_sqe_files_unregister(ctx);
return ret;
}
ref_node = alloc_fixed_file_ref_node(ctx);
if (IS_ERR(ref_node)) {
io_sqe_files_unregister(ctx);
return PTR_ERR(ref_node);
}
file_data->node = ref_node;
spin_lock(&file_data->lock);
list_add_tail(&ref_node->node, &file_data->ref_list);
spin_unlock(&file_data->lock);
percpu_ref_get(&file_data->refs);
return ret;
out_fput:
for (i = 0; i < ctx->nr_user_files; i++) {
file = io_file_from_index(ctx, i);
if (file)
fput(file);
}
for (i = 0; i < nr_tables; i++)
kfree(file_data->table[i].files);
ctx->nr_user_files = 0;
out_ref:
percpu_ref_exit(&file_data->refs);
out_free:
kfree(file_data->table);
kfree(file_data);
ctx->file_data = NULL;
return ret;
}
static int io_sqe_file_register(struct io_ring_ctx *ctx, struct file *file,
int index)
{
#if defined(CONFIG_UNIX)
struct sock *sock = ctx->ring_sock->sk;
struct sk_buff_head *head = &sock->sk_receive_queue;
struct sk_buff *skb;
/*
* See if we can merge this file into an existing skb SCM_RIGHTS
* file set. If there's no room, fall back to allocating a new skb
* and filling it in.
*/
spin_lock_irq(&head->lock);
skb = skb_peek(head);
if (skb) {
struct scm_fp_list *fpl = UNIXCB(skb).fp;
if (fpl->count < SCM_MAX_FD) {
__skb_unlink(skb, head);
spin_unlock_irq(&head->lock);
fpl->fp[fpl->count] = get_file(file);
unix_inflight(fpl->user, fpl->fp[fpl->count]);
fpl->count++;
spin_lock_irq(&head->lock);
__skb_queue_head(head, skb);
} else {
skb = NULL;
}
}
spin_unlock_irq(&head->lock);
if (skb) {
fput(file);
return 0;
}
return __io_sqe_files_scm(ctx, 1, index);
#else
return 0;
#endif
}
static int io_queue_file_removal(struct fixed_file_data *data,
struct file *file)
{
struct io_file_put *pfile;
struct fixed_file_ref_node *ref_node = data->node;
pfile = kzalloc(sizeof(*pfile), GFP_KERNEL);
if (!pfile)
return -ENOMEM;
pfile->file = file;
list_add(&pfile->list, &ref_node->file_list);
return 0;
}
static int __io_sqe_files_update(struct io_ring_ctx *ctx,
struct io_uring_files_update *up,
unsigned nr_args)
{
struct fixed_file_data *data = ctx->file_data;
struct fixed_file_ref_node *ref_node;
struct file *file;
__s32 __user *fds;
int fd, i, err;
__u32 done;
bool needs_switch = false;
if (check_add_overflow(up->offset, nr_args, &done))
return -EOVERFLOW;
if (done > ctx->nr_user_files)
return -EINVAL;
ref_node = alloc_fixed_file_ref_node(ctx);
if (IS_ERR(ref_node))
return PTR_ERR(ref_node);
done = 0;
fds = u64_to_user_ptr(up->fds);
while (nr_args) {
struct fixed_file_table *table;
unsigned index;
err = 0;
if (copy_from_user(&fd, &fds[done], sizeof(fd))) {
err = -EFAULT;
break;
}
i = array_index_nospec(up->offset, ctx->nr_user_files);
table = &ctx->file_data->table[i >> IORING_FILE_TABLE_SHIFT];
index = i & IORING_FILE_TABLE_MASK;
if (table->files[index]) {
file = table->files[index];
err = io_queue_file_removal(data, file);
if (err)
break;
table->files[index] = NULL;
needs_switch = true;
}
if (fd != -1) {
file = fget(fd);
if (!file) {
err = -EBADF;
break;
}
/*
* Don't allow io_uring instances to be registered. If
* UNIX isn't enabled, then this causes a reference
* cycle and this instance can never get freed. If UNIX
* is enabled we'll handle it just fine, but there's
* still no point in allowing a ring fd as it doesn't
* support regular read/write anyway.
*/
if (file->f_op == &io_uring_fops) {
fput(file);
err = -EBADF;
break;
}
table->files[index] = file;
err = io_sqe_file_register(ctx, file, i);
if (err) {
table->files[index] = NULL;
fput(file);
break;
}
}
nr_args--;
done++;
up->offset++;
}
if (needs_switch) {
percpu_ref_kill(&data->node->refs);
spin_lock(&data->lock);
list_add_tail(&ref_node->node, &data->ref_list);
data->node = ref_node;
spin_unlock(&data->lock);
percpu_ref_get(&ctx->file_data->refs);
} else
destroy_fixed_file_ref_node(ref_node);
return done ? done : err;
}
static int io_sqe_files_update(struct io_ring_ctx *ctx, void __user *arg,
unsigned nr_args)
{
struct io_uring_files_update up;
if (!ctx->file_data)
return -ENXIO;
if (!nr_args)
return -EINVAL;
if (copy_from_user(&up, arg, sizeof(up)))
return -EFAULT;
if (up.resv)
return -EINVAL;
return __io_sqe_files_update(ctx, &up, nr_args);
}
static void io_free_work(struct io_wq_work *work)
{
struct io_kiocb *req = container_of(work, struct io_kiocb, work);
/* Consider that io_steal_work() relies on this ref */
io_put_req(req);
}
static int io_init_wq_offload(struct io_ring_ctx *ctx,
struct io_uring_params *p)
{
struct io_wq_data data;
struct fd f;
struct io_ring_ctx *ctx_attach;
unsigned int concurrency;
int ret = 0;
data.user = ctx->user;
data.free_work = io_free_work;
data.do_work = io_wq_submit_work;
if (!(p->flags & IORING_SETUP_ATTACH_WQ)) {
/* Do QD, or 4 * CPUS, whatever is smallest */
concurrency = min(ctx->sq_entries, 4 * num_online_cpus());
ctx->io_wq = io_wq_create(concurrency, &data);
if (IS_ERR(ctx->io_wq)) {
ret = PTR_ERR(ctx->io_wq);
ctx->io_wq = NULL;
}
return ret;
}
f = fdget(p->wq_fd);
if (!f.file)
return -EBADF;
if (f.file->f_op != &io_uring_fops) {
ret = -EINVAL;
goto out_fput;
}
ctx_attach = f.file->private_data;
/* @io_wq is protected by holding the fd */
if (!io_wq_get(ctx_attach->io_wq, &data)) {
ret = -EINVAL;
goto out_fput;
}
ctx->io_wq = ctx_attach->io_wq;
out_fput:
fdput(f);
return ret;
}
static int io_uring_alloc_task_context(struct task_struct *task)
{
struct io_uring_task *tctx;
int ret;
tctx = kmalloc(sizeof(*tctx), GFP_KERNEL);
if (unlikely(!tctx))
return -ENOMEM;
ret = percpu_counter_init(&tctx->inflight, 0, GFP_KERNEL);
if (unlikely(ret)) {
kfree(tctx);
return ret;
}
xa_init(&tctx->xa);
init_waitqueue_head(&tctx->wait);
tctx->last = NULL;
atomic_set(&tctx->in_idle, 0);
tctx->sqpoll = false;
io_init_identity(&tctx->__identity);
tctx->identity = &tctx->__identity;
task->io_uring = tctx;
return 0;
}
void __io_uring_free(struct task_struct *tsk)
{
struct io_uring_task *tctx = tsk->io_uring;
WARN_ON_ONCE(!xa_empty(&tctx->xa));
WARN_ON_ONCE(refcount_read(&tctx->identity->count) != 1);
if (tctx->identity != &tctx->__identity)
kfree(tctx->identity);
percpu_counter_destroy(&tctx->inflight);
kfree(tctx);
tsk->io_uring = NULL;
}
static int io_sq_offload_create(struct io_ring_ctx *ctx,
struct io_uring_params *p)
{
int ret;
if (ctx->flags & IORING_SETUP_SQPOLL) {
struct io_sq_data *sqd;
ret = -EPERM;
if (!capable(CAP_SYS_ADMIN))
goto err;
sqd = io_get_sq_data(p);
if (IS_ERR(sqd)) {
ret = PTR_ERR(sqd);
goto err;
}
ctx->sq_data = sqd;
io_sq_thread_park(sqd);
mutex_lock(&sqd->ctx_lock);
list_add(&ctx->sqd_list, &sqd->ctx_new_list);
mutex_unlock(&sqd->ctx_lock);
io_sq_thread_unpark(sqd);
ctx->sq_thread_idle = msecs_to_jiffies(p->sq_thread_idle);
if (!ctx->sq_thread_idle)
ctx->sq_thread_idle = HZ;
if (sqd->thread)
goto done;
if (p->flags & IORING_SETUP_SQ_AFF) {
int cpu = p->sq_thread_cpu;
ret = -EINVAL;
if (cpu >= nr_cpu_ids)
goto err;
if (!cpu_online(cpu))
goto err;
sqd->thread = kthread_create_on_cpu(io_sq_thread, sqd,
cpu, "io_uring-sq");
} else {
sqd->thread = kthread_create(io_sq_thread, sqd,
"io_uring-sq");
}
if (IS_ERR(sqd->thread)) {
ret = PTR_ERR(sqd->thread);
sqd->thread = NULL;
goto err;
}
ret = io_uring_alloc_task_context(sqd->thread);
if (ret)
goto err;
} else if (p->flags & IORING_SETUP_SQ_AFF) {
/* Can't have SQ_AFF without SQPOLL */
ret = -EINVAL;
goto err;
}
done:
ret = io_init_wq_offload(ctx, p);
if (ret)
goto err;
return 0;
err:
io_finish_async(ctx);
return ret;
}
static void io_sq_offload_start(struct io_ring_ctx *ctx)
{
struct io_sq_data *sqd = ctx->sq_data;
if ((ctx->flags & IORING_SETUP_SQPOLL) && sqd->thread)
wake_up_process(sqd->thread);
}
static inline void __io_unaccount_mem(struct user_struct *user,
unsigned long nr_pages)
{
atomic_long_sub(nr_pages, &user->locked_vm);
}
static inline int __io_account_mem(struct user_struct *user,
unsigned long nr_pages)
{
unsigned long page_limit, cur_pages, new_pages;
/* Don't allow more pages than we can safely lock */
page_limit = rlimit(RLIMIT_MEMLOCK) >> PAGE_SHIFT;
do {
cur_pages = atomic_long_read(&user->locked_vm);
new_pages = cur_pages + nr_pages;
if (new_pages > page_limit)
return -ENOMEM;
} while (atomic_long_cmpxchg(&user->locked_vm, cur_pages,
new_pages) != cur_pages);
return 0;
}
static void io_unaccount_mem(struct io_ring_ctx *ctx, unsigned long nr_pages,
enum io_mem_account acct)
{
if (ctx->limit_mem)
__io_unaccount_mem(ctx->user, nr_pages);
if (ctx->mm_account) {
if (acct == ACCT_LOCKED)
ctx->mm_account->locked_vm -= nr_pages;
else if (acct == ACCT_PINNED)
atomic64_sub(nr_pages, &ctx->mm_account->pinned_vm);
}
}
static int io_account_mem(struct io_ring_ctx *ctx, unsigned long nr_pages,
enum io_mem_account acct)
{
int ret;
if (ctx->limit_mem) {
ret = __io_account_mem(ctx->user, nr_pages);
if (ret)
return ret;
}
if (ctx->mm_account) {
if (acct == ACCT_LOCKED)
ctx->mm_account->locked_vm += nr_pages;
else if (acct == ACCT_PINNED)
atomic64_add(nr_pages, &ctx->mm_account->pinned_vm);
}
return 0;
}
static void io_mem_free(void *ptr)
{
struct page *page;
if (!ptr)
return;
page = virt_to_head_page(ptr);
if (put_page_testzero(page))
free_compound_page(page);
}
static void *io_mem_alloc(size_t size)
{
gfp_t gfp_flags = GFP_KERNEL | __GFP_ZERO | __GFP_NOWARN | __GFP_COMP |
__GFP_NORETRY;
return (void *) __get_free_pages(gfp_flags, get_order(size));
}
static unsigned long rings_size(unsigned sq_entries, unsigned cq_entries,
size_t *sq_offset)
{
struct io_rings *rings;
size_t off, sq_array_size;
off = struct_size(rings, cqes, cq_entries);
if (off == SIZE_MAX)
return SIZE_MAX;
#ifdef CONFIG_SMP
off = ALIGN(off, SMP_CACHE_BYTES);
if (off == 0)
return SIZE_MAX;
#endif
if (sq_offset)
*sq_offset = off;
sq_array_size = array_size(sizeof(u32), sq_entries);
if (sq_array_size == SIZE_MAX)
return SIZE_MAX;
if (check_add_overflow(off, sq_array_size, &off))
return SIZE_MAX;
return off;
}
static unsigned long ring_pages(unsigned sq_entries, unsigned cq_entries)
{
size_t pages;
pages = (size_t)1 << get_order(
rings_size(sq_entries, cq_entries, NULL));
pages += (size_t)1 << get_order(
array_size(sizeof(struct io_uring_sqe), sq_entries));
return pages;
}
static int io_sqe_buffer_unregister(struct io_ring_ctx *ctx)
{
int i, j;
if (!ctx->user_bufs)
return -ENXIO;
for (i = 0; i < ctx->nr_user_bufs; i++) {
struct io_mapped_ubuf *imu = &ctx->user_bufs[i];
for (j = 0; j < imu->nr_bvecs; j++)
unpin_user_page(imu->bvec[j].bv_page);
if (imu->acct_pages)
io_unaccount_mem(ctx, imu->acct_pages, ACCT_PINNED);
kvfree(imu->bvec);
imu->nr_bvecs = 0;
}
kfree(ctx->user_bufs);
ctx->user_bufs = NULL;
ctx->nr_user_bufs = 0;
return 0;
}
static int io_copy_iov(struct io_ring_ctx *ctx, struct iovec *dst,
void __user *arg, unsigned index)
{
struct iovec __user *src;
#ifdef CONFIG_COMPAT
if (ctx->compat) {
struct compat_iovec __user *ciovs;
struct compat_iovec ciov;
ciovs = (struct compat_iovec __user *) arg;
if (copy_from_user(&ciov, &ciovs[index], sizeof(ciov)))
return -EFAULT;
dst->iov_base = u64_to_user_ptr((u64)ciov.iov_base);
dst->iov_len = ciov.iov_len;
return 0;
}
#endif
src = (struct iovec __user *) arg;
if (copy_from_user(dst, &src[index], sizeof(*dst)))
return -EFAULT;
return 0;
}
/*
* Not super efficient, but this is just a registration time. And we do cache
* the last compound head, so generally we'll only do a full search if we don't
* match that one.
*
* We check if the given compound head page has already been accounted, to
* avoid double accounting it. This allows us to account the full size of the
* page, not just the constituent pages of a huge page.
*/
static bool headpage_already_acct(struct io_ring_ctx *ctx, struct page **pages,
int nr_pages, struct page *hpage)
{
int i, j;
/* check current page array */
for (i = 0; i < nr_pages; i++) {
if (!PageCompound(pages[i]))
continue;
if (compound_head(pages[i]) == hpage)
return true;
}
/* check previously registered pages */
for (i = 0; i < ctx->nr_user_bufs; i++) {
struct io_mapped_ubuf *imu = &ctx->user_bufs[i];
for (j = 0; j < imu->nr_bvecs; j++) {
if (!PageCompound(imu->bvec[j].bv_page))
continue;
if (compound_head(imu->bvec[j].bv_page) == hpage)
return true;
}
}
return false;
}
static int io_buffer_account_pin(struct io_ring_ctx *ctx, struct page **pages,
int nr_pages, struct io_mapped_ubuf *imu,
struct page **last_hpage)
{
int i, ret;
for (i = 0; i < nr_pages; i++) {
if (!PageCompound(pages[i])) {
imu->acct_pages++;
} else {
struct page *hpage;
hpage = compound_head(pages[i]);
if (hpage == *last_hpage)
continue;
*last_hpage = hpage;
if (headpage_already_acct(ctx, pages, i, hpage))
continue;
imu->acct_pages += page_size(hpage) >> PAGE_SHIFT;
}
}
if (!imu->acct_pages)
return 0;
ret = io_account_mem(ctx, imu->acct_pages, ACCT_PINNED);
if (ret)
imu->acct_pages = 0;
return ret;
}
static int io_sqe_buffer_register(struct io_ring_ctx *ctx, void __user *arg,
unsigned nr_args)
{
struct vm_area_struct **vmas = NULL;
struct page **pages = NULL;
struct page *last_hpage = NULL;
int i, j, got_pages = 0;
int ret = -EINVAL;
if (ctx->user_bufs)
return -EBUSY;
if (!nr_args || nr_args > UIO_MAXIOV)
return -EINVAL;
ctx->user_bufs = kcalloc(nr_args, sizeof(struct io_mapped_ubuf),
GFP_KERNEL);
if (!ctx->user_bufs)
return -ENOMEM;
for (i = 0; i < nr_args; i++) {
struct io_mapped_ubuf *imu = &ctx->user_bufs[i];
unsigned long off, start, end, ubuf;
int pret, nr_pages;
struct iovec iov;
size_t size;
ret = io_copy_iov(ctx, &iov, arg, i);
if (ret)
goto err;
/*
* Don't impose further limits on the size and buffer
* constraints here, we'll -EINVAL later when IO is
* submitted if they are wrong.
*/
ret = -EFAULT;
if (!iov.iov_base || !iov.iov_len)
goto err;
/* arbitrary limit, but we need something */
if (iov.iov_len > SZ_1G)
goto err;
ubuf = (unsigned long) iov.iov_base;
end = (ubuf + iov.iov_len + PAGE_SIZE - 1) >> PAGE_SHIFT;
start = ubuf >> PAGE_SHIFT;
nr_pages = end - start;
ret = 0;
if (!pages || nr_pages > got_pages) {
kvfree(vmas);
kvfree(pages);
pages = kvmalloc_array(nr_pages, sizeof(struct page *),
GFP_KERNEL);
vmas = kvmalloc_array(nr_pages,
sizeof(struct vm_area_struct *),
GFP_KERNEL);
if (!pages || !vmas) {
ret = -ENOMEM;
goto err;
}
got_pages = nr_pages;
}
imu->bvec = kvmalloc_array(nr_pages, sizeof(struct bio_vec),
GFP_KERNEL);
ret = -ENOMEM;
if (!imu->bvec)
goto err;
ret = 0;
mmap_read_lock(current->mm);
pret = pin_user_pages(ubuf, nr_pages,
FOLL_WRITE | FOLL_LONGTERM,
pages, vmas);
if (pret == nr_pages) {
/* don't support file backed memory */
for (j = 0; j < nr_pages; j++) {
struct vm_area_struct *vma = vmas[j];
if (vma->vm_file &&
!is_file_hugepages(vma->vm_file)) {
ret = -EOPNOTSUPP;
break;
}
}
} else {
ret = pret < 0 ? pret : -EFAULT;
}
mmap_read_unlock(current->mm);
if (ret) {
/*
* if we did partial map, or found file backed vmas,
* release any pages we did get
*/
if (pret > 0)
unpin_user_pages(pages, pret);
kvfree(imu->bvec);
goto err;
}
ret = io_buffer_account_pin(ctx, pages, pret, imu, &last_hpage);
if (ret) {
unpin_user_pages(pages, pret);
kvfree(imu->bvec);
goto err;
}
off = ubuf & ~PAGE_MASK;
size = iov.iov_len;
for (j = 0; j < nr_pages; j++) {
size_t vec_len;
vec_len = min_t(size_t, size, PAGE_SIZE - off);
imu->bvec[j].bv_page = pages[j];
imu->bvec[j].bv_len = vec_len;
imu->bvec[j].bv_offset = off;
off = 0;
size -= vec_len;
}
/* store original address for later verification */
imu->ubuf = ubuf;
imu->len = iov.iov_len;
imu->nr_bvecs = nr_pages;
ctx->nr_user_bufs++;
}
kvfree(pages);
kvfree(vmas);
return 0;
err:
kvfree(pages);
kvfree(vmas);
io_sqe_buffer_unregister(ctx);
return ret;
}
static int io_eventfd_register(struct io_ring_ctx *ctx, void __user *arg)
{
__s32 __user *fds = arg;
int fd;
if (ctx->cq_ev_fd)
return -EBUSY;
if (copy_from_user(&fd, fds, sizeof(*fds)))
return -EFAULT;
ctx->cq_ev_fd = eventfd_ctx_fdget(fd);
if (IS_ERR(ctx->cq_ev_fd)) {
int ret = PTR_ERR(ctx->cq_ev_fd);
ctx->cq_ev_fd = NULL;
return ret;
}
return 0;
}
static int io_eventfd_unregister(struct io_ring_ctx *ctx)
{
if (ctx->cq_ev_fd) {
eventfd_ctx_put(ctx->cq_ev_fd);
ctx->cq_ev_fd = NULL;
return 0;
}
return -ENXIO;
}
static int __io_destroy_buffers(int id, void *p, void *data)
{
struct io_ring_ctx *ctx = data;
struct io_buffer *buf = p;
__io_remove_buffers(ctx, buf, id, -1U);
return 0;
}
static void io_destroy_buffers(struct io_ring_ctx *ctx)
{
idr_for_each(&ctx->io_buffer_idr, __io_destroy_buffers, ctx);
idr_destroy(&ctx->io_buffer_idr);
}
static void io_ring_ctx_free(struct io_ring_ctx *ctx)
{
io_finish_async(ctx);
io_sqe_buffer_unregister(ctx);
if (ctx->sqo_task) {
put_task_struct(ctx->sqo_task);
ctx->sqo_task = NULL;
mmdrop(ctx->mm_account);
ctx->mm_account = NULL;
}
#ifdef CONFIG_BLK_CGROUP
if (ctx->sqo_blkcg_css)
css_put(ctx->sqo_blkcg_css);
#endif
io_sqe_files_unregister(ctx);
io_eventfd_unregister(ctx);
io_destroy_buffers(ctx);
idr_destroy(&ctx->personality_idr);
#if defined(CONFIG_UNIX)
if (ctx->ring_sock) {
ctx->ring_sock->file = NULL; /* so that iput() is called */
sock_release(ctx->ring_sock);
}
#endif
io_mem_free(ctx->rings);
io_mem_free(ctx->sq_sqes);
percpu_ref_exit(&ctx->refs);
free_uid(ctx->user);
put_cred(ctx->creds);
kfree(ctx->cancel_hash);
kmem_cache_free(req_cachep, ctx->fallback_req);
kfree(ctx);
}
static __poll_t io_uring_poll(struct file *file, poll_table *wait)
{
struct io_ring_ctx *ctx = file->private_data;
__poll_t mask = 0;
poll_wait(file, &ctx->cq_wait, wait);
/*
* synchronizes with barrier from wq_has_sleeper call in
* io_commit_cqring
*/
smp_rmb();
if (!io_sqring_full(ctx))
mask |= EPOLLOUT | EPOLLWRNORM;
if (io_cqring_events(ctx, false))
mask |= EPOLLIN | EPOLLRDNORM;
return mask;
}
static int io_uring_fasync(int fd, struct file *file, int on)
{
struct io_ring_ctx *ctx = file->private_data;
return fasync_helper(fd, file, on, &ctx->cq_fasync);
}
static int io_remove_personalities(int id, void *p, void *data)
{
struct io_ring_ctx *ctx = data;
struct io_identity *iod;
iod = idr_remove(&ctx->personality_idr, id);
if (iod) {
put_cred(iod->creds);
if (refcount_dec_and_test(&iod->count))
kfree(iod);
}
return 0;
}
static void io_ring_exit_work(struct work_struct *work)
{
struct io_ring_ctx *ctx = container_of(work, struct io_ring_ctx,
exit_work);
/*
* If we're doing polled IO and end up having requests being
* submitted async (out-of-line), then completions can come in while
* we're waiting for refs to drop. We need to reap these manually,
* as nobody else will be looking for them.
*/
do {
if (ctx->rings)
io_cqring_overflow_flush(ctx, true, NULL, NULL);
io_iopoll_try_reap_events(ctx);
} while (!wait_for_completion_timeout(&ctx->ref_comp, HZ/20));
io_ring_ctx_free(ctx);
}
static void io_ring_ctx_wait_and_kill(struct io_ring_ctx *ctx)
{
mutex_lock(&ctx->uring_lock);
percpu_ref_kill(&ctx->refs);
mutex_unlock(&ctx->uring_lock);
io_kill_timeouts(ctx, NULL);
io_poll_remove_all(ctx, NULL);
if (ctx->io_wq)
io_wq_cancel_all(ctx->io_wq);
/* if we failed setting up the ctx, we might not have any rings */
if (ctx->rings)
io_cqring_overflow_flush(ctx, true, NULL, NULL);
io_iopoll_try_reap_events(ctx);
idr_for_each(&ctx->personality_idr, io_remove_personalities, ctx);
/*
* Do this upfront, so we won't have a grace period where the ring
* is closed but resources aren't reaped yet. This can cause
* spurious failure in setting up a new ring.
*/
io_unaccount_mem(ctx, ring_pages(ctx->sq_entries, ctx->cq_entries),
ACCT_LOCKED);
INIT_WORK(&ctx->exit_work, io_ring_exit_work);
/*
* Use system_unbound_wq to avoid spawning tons of event kworkers
* if we're exiting a ton of rings at the same time. It just adds
* noise and overhead, there's no discernable change in runtime
* over using system_wq.
*/
queue_work(system_unbound_wq, &ctx->exit_work);
}
static int io_uring_release(struct inode *inode, struct file *file)
{
struct io_ring_ctx *ctx = file->private_data;
file->private_data = NULL;
io_ring_ctx_wait_and_kill(ctx);
return 0;
}
static bool io_wq_files_match(struct io_wq_work *work, void *data)
{
struct files_struct *files = data;
return !files || ((work->flags & IO_WQ_WORK_FILES) &&
work->identity->files == files);
}
/*
* Returns true if 'preq' is the link parent of 'req'
*/
static bool io_match_link(struct io_kiocb *preq, struct io_kiocb *req)
{
struct io_kiocb *link;
if (!(preq->flags & REQ_F_LINK_HEAD))
return false;
list_for_each_entry(link, &preq->link_list, link_list) {
if (link == req)
return true;
}
return false;
}
/*
* We're looking to cancel 'req' because it's holding on to our files, but
* 'req' could be a link to another request. See if it is, and cancel that
* parent request if so.
*/
static bool io_poll_remove_link(struct io_ring_ctx *ctx, struct io_kiocb *req)
{
struct hlist_node *tmp;
struct io_kiocb *preq;
bool found = false;
int i;
spin_lock_irq(&ctx->completion_lock);
for (i = 0; i < (1U << ctx->cancel_hash_bits); i++) {
struct hlist_head *list;
list = &ctx->cancel_hash[i];
hlist_for_each_entry_safe(preq, tmp, list, hash_node) {
found = io_match_link(preq, req);
if (found) {
io_poll_remove_one(preq);
break;
}
}
}
spin_unlock_irq(&ctx->completion_lock);
return found;
}
static bool io_timeout_remove_link(struct io_ring_ctx *ctx,
struct io_kiocb *req)
{
struct io_kiocb *preq;
bool found = false;
spin_lock_irq(&ctx->completion_lock);
list_for_each_entry(preq, &ctx->timeout_list, timeout.list) {
found = io_match_link(preq, req);
if (found) {
__io_timeout_cancel(preq);
break;
}
}
spin_unlock_irq(&ctx->completion_lock);
return found;
}
static bool io_cancel_link_cb(struct io_wq_work *work, void *data)
{
struct io_kiocb *req = container_of(work, struct io_kiocb, work);
bool ret;
if (req->flags & REQ_F_LINK_TIMEOUT) {
unsigned long flags;
struct io_ring_ctx *ctx = req->ctx;
/* protect against races with linked timeouts */
spin_lock_irqsave(&ctx->completion_lock, flags);
ret = io_match_link(req, data);
spin_unlock_irqrestore(&ctx->completion_lock, flags);
} else {
ret = io_match_link(req, data);
}
return ret;
}
static void io_attempt_cancel(struct io_ring_ctx *ctx, struct io_kiocb *req)
{
enum io_wq_cancel cret;
/* cancel this particular work, if it's running */
cret = io_wq_cancel_work(ctx->io_wq, &req->work);
if (cret != IO_WQ_CANCEL_NOTFOUND)
return;
/* find links that hold this pending, cancel those */
cret = io_wq_cancel_cb(ctx->io_wq, io_cancel_link_cb, req, true);
if (cret != IO_WQ_CANCEL_NOTFOUND)
return;
/* if we have a poll link holding this pending, cancel that */
if (io_poll_remove_link(ctx, req))
return;
/* final option, timeout link is holding this req pending */
io_timeout_remove_link(ctx, req);
}
static void io_cancel_defer_files(struct io_ring_ctx *ctx,
struct task_struct *task,
struct files_struct *files)
{
struct io_defer_entry *de = NULL;
LIST_HEAD(list);
spin_lock_irq(&ctx->completion_lock);
list_for_each_entry_reverse(de, &ctx->defer_list, list) {
if (io_task_match(de->req, task) &&
io_match_files(de->req, files)) {
list_cut_position(&list, &ctx->defer_list, &de->list);
break;
}
}
spin_unlock_irq(&ctx->completion_lock);
while (!list_empty(&list)) {
de = list_first_entry(&list, struct io_defer_entry, list);
list_del_init(&de->list);
req_set_fail_links(de->req);
io_put_req(de->req);
io_req_complete(de->req, -ECANCELED);
kfree(de);
}
}
/*
* Returns true if we found and killed one or more files pinning requests
*/
static bool io_uring_cancel_files(struct io_ring_ctx *ctx,
struct files_struct *files)
{
if (list_empty_careful(&ctx->inflight_list))
return false;
/* cancel all at once, should be faster than doing it one by one*/
io_wq_cancel_cb(ctx->io_wq, io_wq_files_match, files, true);
while (!list_empty_careful(&ctx->inflight_list)) {
struct io_kiocb *cancel_req = NULL, *req;
DEFINE_WAIT(wait);
spin_lock_irq(&ctx->inflight_lock);
list_for_each_entry(req, &ctx->inflight_list, inflight_entry) {
if (files && (req->work.flags & IO_WQ_WORK_FILES) &&
req->work.identity->files != files)
continue;
/* req is being completed, ignore */
if (!refcount_inc_not_zero(&req->refs))
continue;
cancel_req = req;
break;
}
if (cancel_req)
prepare_to_wait(&ctx->inflight_wait, &wait,
TASK_UNINTERRUPTIBLE);
spin_unlock_irq(&ctx->inflight_lock);
/* We need to keep going until we don't find a matching req */
if (!cancel_req)
break;
/* cancel this request, or head link requests */
io_attempt_cancel(ctx, cancel_req);
io_put_req(cancel_req);
/* cancellations _may_ trigger task work */
io_run_task_work();
schedule();
finish_wait(&ctx->inflight_wait, &wait);
}
return true;
}
static bool io_cancel_task_cb(struct io_wq_work *work, void *data)
{
struct io_kiocb *req = container_of(work, struct io_kiocb, work);
struct task_struct *task = data;
return io_task_match(req, task);
}
static bool __io_uring_cancel_task_requests(struct io_ring_ctx *ctx,
struct task_struct *task,
struct files_struct *files)
{
bool ret;
ret = io_uring_cancel_files(ctx, files);
if (!files) {
enum io_wq_cancel cret;
cret = io_wq_cancel_cb(ctx->io_wq, io_cancel_task_cb, task, true);
if (cret != IO_WQ_CANCEL_NOTFOUND)
ret = true;
/* SQPOLL thread does its own polling */
if (!(ctx->flags & IORING_SETUP_SQPOLL)) {
while (!list_empty_careful(&ctx->iopoll_list)) {
io_iopoll_try_reap_events(ctx);
ret = true;
}
}
ret |= io_poll_remove_all(ctx, task);
ret |= io_kill_timeouts(ctx, task);
}
return ret;
}
/*
* We need to iteratively cancel requests, in case a request has dependent
* hard links. These persist even for failure of cancelations, hence keep
* looping until none are found.
*/
static void io_uring_cancel_task_requests(struct io_ring_ctx *ctx,
struct files_struct *files)
{
struct task_struct *task = current;
if ((ctx->flags & IORING_SETUP_SQPOLL) && ctx->sq_data) {
task = ctx->sq_data->thread;
atomic_inc(&task->io_uring->in_idle);
io_sq_thread_park(ctx->sq_data);
}
if (files)
io_cancel_defer_files(ctx, NULL, files);
else
io_cancel_defer_files(ctx, task, NULL);
io_cqring_overflow_flush(ctx, true, task, files);
while (__io_uring_cancel_task_requests(ctx, task, files)) {
io_run_task_work();
cond_resched();
}
if ((ctx->flags & IORING_SETUP_SQPOLL) && ctx->sq_data) {
atomic_dec(&task->io_uring->in_idle);
/*
* If the files that are going away are the ones in the thread
* identity, clear them out.
*/
if (task->io_uring->identity->files == files)
task->io_uring->identity->files = NULL;
io_sq_thread_unpark(ctx->sq_data);
}
}
/*
* Note that this task has used io_uring. We use it for cancelation purposes.
*/
static int io_uring_add_task_file(struct io_ring_ctx *ctx, struct file *file)
{
struct io_uring_task *tctx = current->io_uring;
if (unlikely(!tctx)) {
int ret;
ret = io_uring_alloc_task_context(current);
if (unlikely(ret))
return ret;
tctx = current->io_uring;
}
if (tctx->last != file) {
void *old = xa_load(&tctx->xa, (unsigned long)file);
if (!old) {
get_file(file);
xa_store(&tctx->xa, (unsigned long)file, file, GFP_KERNEL);
}
tctx->last = file;
}
/*
* This is race safe in that the task itself is doing this, hence it
* cannot be going through the exit/cancel paths at the same time.
* This cannot be modified while exit/cancel is running.
*/
if (!tctx->sqpoll && (ctx->flags & IORING_SETUP_SQPOLL))
tctx->sqpoll = true;
return 0;
}
/*
* Remove this io_uring_file -> task mapping.
*/
static void io_uring_del_task_file(struct file *file)
{
struct io_uring_task *tctx = current->io_uring;
if (tctx->last == file)
tctx->last = NULL;
file = xa_erase(&tctx->xa, (unsigned long)file);
if (file)
fput(file);
}
/*
* Drop task note for this file if we're the only ones that hold it after
* pending fput()
*/
static void io_uring_attempt_task_drop(struct file *file)
{
if (!current->io_uring)
return;
/*
* fput() is pending, will be 2 if the only other ref is our potential
* task file note. If the task is exiting, drop regardless of count.
*/
if (fatal_signal_pending(current) || (current->flags & PF_EXITING) ||
atomic_long_read(&file->f_count) == 2)
io_uring_del_task_file(file);
}
void __io_uring_files_cancel(struct files_struct *files)
{
struct io_uring_task *tctx = current->io_uring;
struct file *file;
unsigned long index;
/* make sure overflow events are dropped */
atomic_inc(&tctx->in_idle);
xa_for_each(&tctx->xa, index, file) {
struct io_ring_ctx *ctx = file->private_data;
io_uring_cancel_task_requests(ctx, files);
if (files)
io_uring_del_task_file(file);
}
atomic_dec(&tctx->in_idle);
}
static s64 tctx_inflight(struct io_uring_task *tctx)
{
unsigned long index;
struct file *file;
s64 inflight;
inflight = percpu_counter_sum(&tctx->inflight);
if (!tctx->sqpoll)
return inflight;
/*
* If we have SQPOLL rings, then we need to iterate and find them, and
* add the pending count for those.
*/
xa_for_each(&tctx->xa, index, file) {
struct io_ring_ctx *ctx = file->private_data;
if (ctx->flags & IORING_SETUP_SQPOLL) {
struct io_uring_task *__tctx = ctx->sqo_task->io_uring;
inflight += percpu_counter_sum(&__tctx->inflight);
}
}
return inflight;
}
/*
* Find any io_uring fd that this task has registered or done IO on, and cancel
* requests.
*/
void __io_uring_task_cancel(void)
{
struct io_uring_task *tctx = current->io_uring;
DEFINE_WAIT(wait);
s64 inflight;
/* make sure overflow events are dropped */
atomic_inc(&tctx->in_idle);
do {
/* read completions before cancelations */
inflight = tctx_inflight(tctx);
if (!inflight)
break;
__io_uring_files_cancel(NULL);
prepare_to_wait(&tctx->wait, &wait, TASK_UNINTERRUPTIBLE);
/*
* If we've seen completions, retry. This avoids a race where
* a completion comes in before we did prepare_to_wait().
*/
if (inflight != tctx_inflight(tctx))
continue;
schedule();
} while (1);
finish_wait(&tctx->wait, &wait);
atomic_dec(&tctx->in_idle);
}
static int io_uring_flush(struct file *file, void *data)
{
io_uring_attempt_task_drop(file);
return 0;
}
static void *io_uring_validate_mmap_request(struct file *file,
loff_t pgoff, size_t sz)
{
struct io_ring_ctx *ctx = file->private_data;
loff_t offset = pgoff << PAGE_SHIFT;
struct page *page;
void *ptr;
switch (offset) {
case IORING_OFF_SQ_RING:
case IORING_OFF_CQ_RING:
ptr = ctx->rings;
break;
case IORING_OFF_SQES:
ptr = ctx->sq_sqes;
break;
default:
return ERR_PTR(-EINVAL);
}
page = virt_to_head_page(ptr);
if (sz > page_size(page))
return ERR_PTR(-EINVAL);
return ptr;
}
#ifdef CONFIG_MMU
static int io_uring_mmap(struct file *file, struct vm_area_struct *vma)
{
size_t sz = vma->vm_end - vma->vm_start;
unsigned long pfn;
void *ptr;
ptr = io_uring_validate_mmap_request(file, vma->vm_pgoff, sz);
if (IS_ERR(ptr))
return PTR_ERR(ptr);
pfn = virt_to_phys(ptr) >> PAGE_SHIFT;
return remap_pfn_range(vma, vma->vm_start, pfn, sz, vma->vm_page_prot);
}
#else /* !CONFIG_MMU */
static int io_uring_mmap(struct file *file, struct vm_area_struct *vma)
{
return vma->vm_flags & (VM_SHARED | VM_MAYSHARE) ? 0 : -EINVAL;
}
static unsigned int io_uring_nommu_mmap_capabilities(struct file *file)
{
return NOMMU_MAP_DIRECT | NOMMU_MAP_READ | NOMMU_MAP_WRITE;
}
static unsigned long io_uring_nommu_get_unmapped_area(struct file *file,
unsigned long addr, unsigned long len,
unsigned long pgoff, unsigned long flags)
{
void *ptr;
ptr = io_uring_validate_mmap_request(file, pgoff, len);
if (IS_ERR(ptr))
return PTR_ERR(ptr);
return (unsigned long) ptr;
}
#endif /* !CONFIG_MMU */
static void io_sqpoll_wait_sq(struct io_ring_ctx *ctx)
{
DEFINE_WAIT(wait);
do {
if (!io_sqring_full(ctx))
break;
prepare_to_wait(&ctx->sqo_sq_wait, &wait, TASK_INTERRUPTIBLE);
if (!io_sqring_full(ctx))
break;
schedule();
} while (!signal_pending(current));
finish_wait(&ctx->sqo_sq_wait, &wait);
}
SYSCALL_DEFINE6(io_uring_enter, unsigned int, fd, u32, to_submit,
u32, min_complete, u32, flags, const sigset_t __user *, sig,
size_t, sigsz)
{
struct io_ring_ctx *ctx;
long ret = -EBADF;
int submitted = 0;
struct fd f;
io_run_task_work();
if (flags & ~(IORING_ENTER_GETEVENTS | IORING_ENTER_SQ_WAKEUP |
IORING_ENTER_SQ_WAIT))
return -EINVAL;
f = fdget(fd);
if (!f.file)
return -EBADF;
ret = -EOPNOTSUPP;
if (f.file->f_op != &io_uring_fops)
goto out_fput;
ret = -ENXIO;
ctx = f.file->private_data;
if (!percpu_ref_tryget(&ctx->refs))
goto out_fput;
ret = -EBADFD;
if (ctx->flags & IORING_SETUP_R_DISABLED)
goto out;
/*
* For SQ polling, the thread will do all submissions and completions.
* Just return the requested submit count, and wake the thread if
* we were asked to.
*/
ret = 0;
if (ctx->flags & IORING_SETUP_SQPOLL) {
if (!list_empty_careful(&ctx->cq_overflow_list))
io_cqring_overflow_flush(ctx, false, NULL, NULL);
if (flags & IORING_ENTER_SQ_WAKEUP)
wake_up(&ctx->sq_data->wait);
if (flags & IORING_ENTER_SQ_WAIT)
io_sqpoll_wait_sq(ctx);
submitted = to_submit;
} else if (to_submit) {
ret = io_uring_add_task_file(ctx, f.file);
if (unlikely(ret))
goto out;
mutex_lock(&ctx->uring_lock);
submitted = io_submit_sqes(ctx, to_submit);
mutex_unlock(&ctx->uring_lock);
if (submitted != to_submit)
goto out;
}
if (flags & IORING_ENTER_GETEVENTS) {
min_complete = min(min_complete, ctx->cq_entries);
/*
* When SETUP_IOPOLL and SETUP_SQPOLL are both enabled, user
* space applications don't need to do io completion events
* polling again, they can rely on io_sq_thread to do polling
* work, which can reduce cpu usage and uring_lock contention.
*/
if (ctx->flags & IORING_SETUP_IOPOLL &&
!(ctx->flags & IORING_SETUP_SQPOLL)) {
ret = io_iopoll_check(ctx, min_complete);
} else {
ret = io_cqring_wait(ctx, min_complete, sig, sigsz);
}
}
out:
percpu_ref_put(&ctx->refs);
out_fput:
fdput(f);
return submitted ? submitted : ret;
}
#ifdef CONFIG_PROC_FS
static int io_uring_show_cred(int id, void *p, void *data)
{
struct io_identity *iod = p;
const struct cred *cred = iod->creds;
struct seq_file *m = data;
struct user_namespace *uns = seq_user_ns(m);
struct group_info *gi;
kernel_cap_t cap;
unsigned __capi;
int g;
seq_printf(m, "%5d\n", id);
seq_put_decimal_ull(m, "\tUid:\t", from_kuid_munged(uns, cred->uid));
seq_put_decimal_ull(m, "\t\t", from_kuid_munged(uns, cred->euid));
seq_put_decimal_ull(m, "\t\t", from_kuid_munged(uns, cred->suid));
seq_put_decimal_ull(m, "\t\t", from_kuid_munged(uns, cred->fsuid));
seq_put_decimal_ull(m, "\n\tGid:\t", from_kgid_munged(uns, cred->gid));
seq_put_decimal_ull(m, "\t\t", from_kgid_munged(uns, cred->egid));
seq_put_decimal_ull(m, "\t\t", from_kgid_munged(uns, cred->sgid));
seq_put_decimal_ull(m, "\t\t", from_kgid_munged(uns, cred->fsgid));
seq_puts(m, "\n\tGroups:\t");
gi = cred->group_info;
for (g = 0; g < gi->ngroups; g++) {
seq_put_decimal_ull(m, g ? " " : "",
from_kgid_munged(uns, gi->gid[g]));
}
seq_puts(m, "\n\tCapEff:\t");
cap = cred->cap_effective;
CAP_FOR_EACH_U32(__capi)
seq_put_hex_ll(m, NULL, cap.cap[CAP_LAST_U32 - __capi], 8);
seq_putc(m, '\n');
return 0;
}
static void __io_uring_show_fdinfo(struct io_ring_ctx *ctx, struct seq_file *m)
{
struct io_sq_data *sq = NULL;
bool has_lock;
int i;
/*
* Avoid ABBA deadlock between the seq lock and the io_uring mutex,
* since fdinfo case grabs it in the opposite direction of normal use
* cases. If we fail to get the lock, we just don't iterate any
* structures that could be going away outside the io_uring mutex.
*/
has_lock = mutex_trylock(&ctx->uring_lock);
if (has_lock && (ctx->flags & IORING_SETUP_SQPOLL))
sq = ctx->sq_data;
seq_printf(m, "SqThread:\t%d\n", sq ? task_pid_nr(sq->thread) : -1);
seq_printf(m, "SqThreadCpu:\t%d\n", sq ? task_cpu(sq->thread) : -1);
seq_printf(m, "UserFiles:\t%u\n", ctx->nr_user_files);
for (i = 0; has_lock && i < ctx->nr_user_files; i++) {
struct fixed_file_table *table;
struct file *f;
table = &ctx->file_data->table[i >> IORING_FILE_TABLE_SHIFT];
f = table->files[i & IORING_FILE_TABLE_MASK];
if (f)
seq_printf(m, "%5u: %s\n", i, file_dentry(f)->d_iname);
else
seq_printf(m, "%5u: <none>\n", i);
}
seq_printf(m, "UserBufs:\t%u\n", ctx->nr_user_bufs);
for (i = 0; has_lock && i < ctx->nr_user_bufs; i++) {
struct io_mapped_ubuf *buf = &ctx->user_bufs[i];
seq_printf(m, "%5u: 0x%llx/%u\n", i, buf->ubuf,
(unsigned int) buf->len);
}
if (has_lock && !idr_is_empty(&ctx->personality_idr)) {
seq_printf(m, "Personalities:\n");
idr_for_each(&ctx->personality_idr, io_uring_show_cred, m);
}
seq_printf(m, "PollList:\n");
spin_lock_irq(&ctx->completion_lock);
for (i = 0; i < (1U << ctx->cancel_hash_bits); i++) {
struct hlist_head *list = &ctx->cancel_hash[i];
struct io_kiocb *req;
hlist_for_each_entry(req, list, hash_node)
seq_printf(m, " op=%d, task_works=%d\n", req->opcode,
req->task->task_works != NULL);
}
spin_unlock_irq(&ctx->completion_lock);
if (has_lock)
mutex_unlock(&ctx->uring_lock);
}
static void io_uring_show_fdinfo(struct seq_file *m, struct file *f)
{
struct io_ring_ctx *ctx = f->private_data;
if (percpu_ref_tryget(&ctx->refs)) {
__io_uring_show_fdinfo(ctx, m);
percpu_ref_put(&ctx->refs);
}
}
#endif
static const struct file_operations io_uring_fops = {
.release = io_uring_release,
.flush = io_uring_flush,
.mmap = io_uring_mmap,
#ifndef CONFIG_MMU
.get_unmapped_area = io_uring_nommu_get_unmapped_area,
.mmap_capabilities = io_uring_nommu_mmap_capabilities,
#endif
.poll = io_uring_poll,
.fasync = io_uring_fasync,
#ifdef CONFIG_PROC_FS
.show_fdinfo = io_uring_show_fdinfo,
#endif
};
static int io_allocate_scq_urings(struct io_ring_ctx *ctx,
struct io_uring_params *p)
{
struct io_rings *rings;
size_t size, sq_array_offset;
/* make sure these are sane, as we already accounted them */
ctx->sq_entries = p->sq_entries;
ctx->cq_entries = p->cq_entries;
size = rings_size(p->sq_entries, p->cq_entries, &sq_array_offset);
if (size == SIZE_MAX)
return -EOVERFLOW;
rings = io_mem_alloc(size);
if (!rings)
return -ENOMEM;
ctx->rings = rings;
ctx->sq_array = (u32 *)((char *)rings + sq_array_offset);
rings->sq_ring_mask = p->sq_entries - 1;
rings->cq_ring_mask = p->cq_entries - 1;
rings->sq_ring_entries = p->sq_entries;
rings->cq_ring_entries = p->cq_entries;
ctx->sq_mask = rings->sq_ring_mask;
ctx->cq_mask = rings->cq_ring_mask;
size = array_size(sizeof(struct io_uring_sqe), p->sq_entries);
if (size == SIZE_MAX) {
io_mem_free(ctx->rings);
ctx->rings = NULL;
return -EOVERFLOW;
}
ctx->sq_sqes = io_mem_alloc(size);
if (!ctx->sq_sqes) {
io_mem_free(ctx->rings);
ctx->rings = NULL;
return -ENOMEM;
}
return 0;
}
/*
* Allocate an anonymous fd, this is what constitutes the application
* visible backing of an io_uring instance. The application mmaps this
* fd to gain access to the SQ/CQ ring details. If UNIX sockets are enabled,
* we have to tie this fd to a socket for file garbage collection purposes.
*/
static int io_uring_get_fd(struct io_ring_ctx *ctx)
{
struct file *file;
int ret;
int fd;
#if defined(CONFIG_UNIX)
ret = sock_create_kern(&init_net, PF_UNIX, SOCK_RAW, IPPROTO_IP,
&ctx->ring_sock);
if (ret)
return ret;
#endif
ret = get_unused_fd_flags(O_RDWR | O_CLOEXEC);
if (ret < 0)
goto err;
fd = ret;
file = anon_inode_getfile("[io_uring]", &io_uring_fops, ctx,
O_RDWR | O_CLOEXEC);
if (IS_ERR(file)) {
put_unused_fd(fd);
ret = PTR_ERR(file);
goto err;
}
#if defined(CONFIG_UNIX)
ctx->ring_sock->file = file;
#endif
ret = io_uring_add_task_file(ctx, file);
if (ret) {
fput(file);
put_unused_fd(fd);
goto err;
}
fd_install(fd, file);
return fd;
err:
#if defined(CONFIG_UNIX)
sock_release(ctx->ring_sock);
ctx->ring_sock = NULL;
#endif
return ret;
}
static int io_uring_create(unsigned entries, struct io_uring_params *p,
struct io_uring_params __user *params)
{
struct user_struct *user = NULL;
struct io_ring_ctx *ctx;
bool limit_mem;
int ret;
if (!entries)
return -EINVAL;
if (entries > IORING_MAX_ENTRIES) {
if (!(p->flags & IORING_SETUP_CLAMP))
return -EINVAL;
entries = IORING_MAX_ENTRIES;
}
/*
* Use twice as many entries for the CQ ring. It's possible for the
* application to drive a higher depth than the size of the SQ ring,
* since the sqes are only used at submission time. This allows for
* some flexibility in overcommitting a bit. If the application has
* set IORING_SETUP_CQSIZE, it will have passed in the desired number
* of CQ ring entries manually.
*/
p->sq_entries = roundup_pow_of_two(entries);
if (p->flags & IORING_SETUP_CQSIZE) {
/*
* If IORING_SETUP_CQSIZE is set, we do the same roundup
* to a power-of-two, if it isn't already. We do NOT impose
* any cq vs sq ring sizing.
*/
if (!p->cq_entries)
return -EINVAL;
if (p->cq_entries > IORING_MAX_CQ_ENTRIES) {
if (!(p->flags & IORING_SETUP_CLAMP))
return -EINVAL;
p->cq_entries = IORING_MAX_CQ_ENTRIES;
}
p->cq_entries = roundup_pow_of_two(p->cq_entries);
if (p->cq_entries < p->sq_entries)
return -EINVAL;
} else {
p->cq_entries = 2 * p->sq_entries;
}
user = get_uid(current_user());
limit_mem = !capable(CAP_IPC_LOCK);
if (limit_mem) {
ret = __io_account_mem(user,
ring_pages(p->sq_entries, p->cq_entries));
if (ret) {
free_uid(user);
return ret;
}
}
ctx = io_ring_ctx_alloc(p);
if (!ctx) {
if (limit_mem)
__io_unaccount_mem(user, ring_pages(p->sq_entries,
p->cq_entries));
free_uid(user);
return -ENOMEM;
}
ctx->compat = in_compat_syscall();
ctx->user = user;
ctx->creds = get_current_cred();
#ifdef CONFIG_AUDIT
ctx->loginuid = current->loginuid;
ctx->sessionid = current->sessionid;
#endif
ctx->sqo_task = get_task_struct(current);
/*
* This is just grabbed for accounting purposes. When a process exits,
* the mm is exited and dropped before the files, hence we need to hang
* on to this mm purely for the purposes of being able to unaccount
* memory (locked/pinned vm). It's not used for anything else.
*/
mmgrab(current->mm);
ctx->mm_account = current->mm;
#ifdef CONFIG_BLK_CGROUP
/*
* The sq thread will belong to the original cgroup it was inited in.
* If the cgroup goes offline (e.g. disabling the io controller), then
* issued bios will be associated with the closest cgroup later in the
* block layer.
*/
rcu_read_lock();
ctx->sqo_blkcg_css = blkcg_css();
ret = css_tryget_online(ctx->sqo_blkcg_css);
rcu_read_unlock();
if (!ret) {
/* don't init against a dying cgroup, have the user try again */
ctx->sqo_blkcg_css = NULL;
ret = -ENODEV;
goto err;
}
#endif
/*
* Account memory _before_ installing the file descriptor. Once
* the descriptor is installed, it can get closed at any time. Also
* do this before hitting the general error path, as ring freeing
* will un-account as well.
*/
io_account_mem(ctx, ring_pages(p->sq_entries, p->cq_entries),
ACCT_LOCKED);
ctx->limit_mem = limit_mem;
ret = io_allocate_scq_urings(ctx, p);
if (ret)
goto err;
ret = io_sq_offload_create(ctx, p);
if (ret)
goto err;
if (!(p->flags & IORING_SETUP_R_DISABLED))
io_sq_offload_start(ctx);
memset(&p->sq_off, 0, sizeof(p->sq_off));
p->sq_off.head = offsetof(struct io_rings, sq.head);
p->sq_off.tail = offsetof(struct io_rings, sq.tail);
p->sq_off.ring_mask = offsetof(struct io_rings, sq_ring_mask);
p->sq_off.ring_entries = offsetof(struct io_rings, sq_ring_entries);
p->sq_off.flags = offsetof(struct io_rings, sq_flags);
p->sq_off.dropped = offsetof(struct io_rings, sq_dropped);
p->sq_off.array = (char *)ctx->sq_array - (char *)ctx->rings;
memset(&p->cq_off, 0, sizeof(p->cq_off));
p->cq_off.head = offsetof(struct io_rings, cq.head);
p->cq_off.tail = offsetof(struct io_rings, cq.tail);
p->cq_off.ring_mask = offsetof(struct io_rings, cq_ring_mask);
p->cq_off.ring_entries = offsetof(struct io_rings, cq_ring_entries);
p->cq_off.overflow = offsetof(struct io_rings, cq_overflow);
p->cq_off.cqes = offsetof(struct io_rings, cqes);
p->cq_off.flags = offsetof(struct io_rings, cq_flags);
p->features = IORING_FEAT_SINGLE_MMAP | IORING_FEAT_NODROP |
IORING_FEAT_SUBMIT_STABLE | IORING_FEAT_RW_CUR_POS |
IORING_FEAT_CUR_PERSONALITY | IORING_FEAT_FAST_POLL |
IORING_FEAT_POLL_32BITS;
if (copy_to_user(params, p, sizeof(*p))) {
ret = -EFAULT;
goto err;
}
/*
* Install ring fd as the very last thing, so we don't risk someone
* having closed it before we finish setup
*/
ret = io_uring_get_fd(ctx);
if (ret < 0)
goto err;
trace_io_uring_create(ret, ctx, p->sq_entries, p->cq_entries, p->flags);
return ret;
err:
io_ring_ctx_wait_and_kill(ctx);
return ret;
}
/*
* Sets up an aio uring context, and returns the fd. Applications asks for a
* ring size, we return the actual sq/cq ring sizes (among other things) in the
* params structure passed in.
*/
static long io_uring_setup(u32 entries, struct io_uring_params __user *params)
{
struct io_uring_params p;
int i;
if (copy_from_user(&p, params, sizeof(p)))
return -EFAULT;
for (i = 0; i < ARRAY_SIZE(p.resv); i++) {
if (p.resv[i])
return -EINVAL;
}
if (p.flags & ~(IORING_SETUP_IOPOLL | IORING_SETUP_SQPOLL |
IORING_SETUP_SQ_AFF | IORING_SETUP_CQSIZE |
IORING_SETUP_CLAMP | IORING_SETUP_ATTACH_WQ |
IORING_SETUP_R_DISABLED))
return -EINVAL;
return io_uring_create(entries, &p, params);
}
SYSCALL_DEFINE2(io_uring_setup, u32, entries,
struct io_uring_params __user *, params)
{
return io_uring_setup(entries, params);
}
static int io_probe(struct io_ring_ctx *ctx, void __user *arg, unsigned nr_args)
{
struct io_uring_probe *p;
size_t size;
int i, ret;
size = struct_size(p, ops, nr_args);
if (size == SIZE_MAX)
return -EOVERFLOW;
p = kzalloc(size, GFP_KERNEL);
if (!p)
return -ENOMEM;
ret = -EFAULT;
if (copy_from_user(p, arg, size))
goto out;
ret = -EINVAL;
if (memchr_inv(p, 0, size))
goto out;
p->last_op = IORING_OP_LAST - 1;
if (nr_args > IORING_OP_LAST)
nr_args = IORING_OP_LAST;
for (i = 0; i < nr_args; i++) {
p->ops[i].op = i;
if (!io_op_defs[i].not_supported)
p->ops[i].flags = IO_URING_OP_SUPPORTED;
}
p->ops_len = i;
ret = 0;
if (copy_to_user(arg, p, size))
ret = -EFAULT;
out:
kfree(p);
return ret;
}
static int io_register_personality(struct io_ring_ctx *ctx)
{
struct io_identity *id;
int ret;
id = kmalloc(sizeof(*id), GFP_KERNEL);
if (unlikely(!id))
return -ENOMEM;
io_init_identity(id);
id->creds = get_current_cred();
ret = idr_alloc_cyclic(&ctx->personality_idr, id, 1, USHRT_MAX, GFP_KERNEL);
if (ret < 0) {
put_cred(id->creds);
kfree(id);
}
return ret;
}
static int io_unregister_personality(struct io_ring_ctx *ctx, unsigned id)
{
struct io_identity *iod;
iod = idr_remove(&ctx->personality_idr, id);
if (iod) {
put_cred(iod->creds);
if (refcount_dec_and_test(&iod->count))
kfree(iod);
return 0;
}
return -EINVAL;
}
static int io_register_restrictions(struct io_ring_ctx *ctx, void __user *arg,
unsigned int nr_args)
{
struct io_uring_restriction *res;
size_t size;
int i, ret;
/* Restrictions allowed only if rings started disabled */
if (!(ctx->flags & IORING_SETUP_R_DISABLED))
return -EBADFD;
/* We allow only a single restrictions registration */
if (ctx->restrictions.registered)
return -EBUSY;
if (!arg || nr_args > IORING_MAX_RESTRICTIONS)
return -EINVAL;
size = array_size(nr_args, sizeof(*res));
if (size == SIZE_MAX)
return -EOVERFLOW;
res = memdup_user(arg, size);
if (IS_ERR(res))
return PTR_ERR(res);
ret = 0;
for (i = 0; i < nr_args; i++) {
switch (res[i].opcode) {
case IORING_RESTRICTION_REGISTER_OP:
if (res[i].register_op >= IORING_REGISTER_LAST) {
ret = -EINVAL;
goto out;
}
__set_bit(res[i].register_op,
ctx->restrictions.register_op);
break;
case IORING_RESTRICTION_SQE_OP:
if (res[i].sqe_op >= IORING_OP_LAST) {
ret = -EINVAL;
goto out;
}
__set_bit(res[i].sqe_op, ctx->restrictions.sqe_op);
break;
case IORING_RESTRICTION_SQE_FLAGS_ALLOWED:
ctx->restrictions.sqe_flags_allowed = res[i].sqe_flags;
break;
case IORING_RESTRICTION_SQE_FLAGS_REQUIRED:
ctx->restrictions.sqe_flags_required = res[i].sqe_flags;
break;
default:
ret = -EINVAL;
goto out;
}
}
out:
/* Reset all restrictions if an error happened */
if (ret != 0)
memset(&ctx->restrictions, 0, sizeof(ctx->restrictions));
else
ctx->restrictions.registered = true;
kfree(res);
return ret;
}
static int io_register_enable_rings(struct io_ring_ctx *ctx)
{
if (!(ctx->flags & IORING_SETUP_R_DISABLED))
return -EBADFD;
if (ctx->restrictions.registered)
ctx->restricted = 1;
ctx->flags &= ~IORING_SETUP_R_DISABLED;
io_sq_offload_start(ctx);
return 0;
}
static bool io_register_op_must_quiesce(int op)
{
switch (op) {
case IORING_UNREGISTER_FILES:
case IORING_REGISTER_FILES_UPDATE:
case IORING_REGISTER_PROBE:
case IORING_REGISTER_PERSONALITY:
case IORING_UNREGISTER_PERSONALITY:
return false;
default:
return true;
}
}
static int __io_uring_register(struct io_ring_ctx *ctx, unsigned opcode,
void __user *arg, unsigned nr_args)
__releases(ctx->uring_lock)
__acquires(ctx->uring_lock)
{
int ret;
/*
* We're inside the ring mutex, if the ref is already dying, then
* someone else killed the ctx or is already going through
* io_uring_register().
*/
if (percpu_ref_is_dying(&ctx->refs))
return -ENXIO;
if (io_register_op_must_quiesce(opcode)) {
percpu_ref_kill(&ctx->refs);
/*
* Drop uring mutex before waiting for references to exit. If
* another thread is currently inside io_uring_enter() it might
* need to grab the uring_lock to make progress. If we hold it
* here across the drain wait, then we can deadlock. It's safe
* to drop the mutex here, since no new references will come in
* after we've killed the percpu ref.
*/
mutex_unlock(&ctx->uring_lock);
do {
ret = wait_for_completion_interruptible(&ctx->ref_comp);
if (!ret)
break;
ret = io_run_task_work_sig();
if (ret < 0)
break;
} while (1);
mutex_lock(&ctx->uring_lock);
if (ret) {
percpu_ref_resurrect(&ctx->refs);
goto out_quiesce;
}
}
if (ctx->restricted) {
if (opcode >= IORING_REGISTER_LAST) {
ret = -EINVAL;
goto out;
}
if (!test_bit(opcode, ctx->restrictions.register_op)) {
ret = -EACCES;
goto out;
}
}
switch (opcode) {
case IORING_REGISTER_BUFFERS:
ret = io_sqe_buffer_register(ctx, arg, nr_args);
break;
case IORING_UNREGISTER_BUFFERS:
ret = -EINVAL;
if (arg || nr_args)
break;
ret = io_sqe_buffer_unregister(ctx);
break;
case IORING_REGISTER_FILES:
ret = io_sqe_files_register(ctx, arg, nr_args);
break;
case IORING_UNREGISTER_FILES:
ret = -EINVAL;
if (arg || nr_args)
break;
ret = io_sqe_files_unregister(ctx);
break;
case IORING_REGISTER_FILES_UPDATE:
ret = io_sqe_files_update(ctx, arg, nr_args);
break;
case IORING_REGISTER_EVENTFD:
case IORING_REGISTER_EVENTFD_ASYNC:
ret = -EINVAL;
if (nr_args != 1)
break;
ret = io_eventfd_register(ctx, arg);
if (ret)
break;
if (opcode == IORING_REGISTER_EVENTFD_ASYNC)
ctx->eventfd_async = 1;
else
ctx->eventfd_async = 0;
break;
case IORING_UNREGISTER_EVENTFD:
ret = -EINVAL;
if (arg || nr_args)
break;
ret = io_eventfd_unregister(ctx);
break;
case IORING_REGISTER_PROBE:
ret = -EINVAL;
if (!arg || nr_args > 256)
break;
ret = io_probe(ctx, arg, nr_args);
break;
case IORING_REGISTER_PERSONALITY:
ret = -EINVAL;
if (arg || nr_args)
break;
ret = io_register_personality(ctx);
break;
case IORING_UNREGISTER_PERSONALITY:
ret = -EINVAL;
if (arg)
break;
ret = io_unregister_personality(ctx, nr_args);
break;
case IORING_REGISTER_ENABLE_RINGS:
ret = -EINVAL;
if (arg || nr_args)
break;
ret = io_register_enable_rings(ctx);
break;
case IORING_REGISTER_RESTRICTIONS:
ret = io_register_restrictions(ctx, arg, nr_args);
break;
default:
ret = -EINVAL;
break;
}
out:
if (io_register_op_must_quiesce(opcode)) {
/* bring the ctx back to life */
percpu_ref_reinit(&ctx->refs);
out_quiesce:
reinit_completion(&ctx->ref_comp);
}
return ret;
}
SYSCALL_DEFINE4(io_uring_register, unsigned int, fd, unsigned int, opcode,
void __user *, arg, unsigned int, nr_args)
{
struct io_ring_ctx *ctx;
long ret = -EBADF;
struct fd f;
f = fdget(fd);
if (!f.file)
return -EBADF;
ret = -EOPNOTSUPP;
if (f.file->f_op != &io_uring_fops)
goto out_fput;
ctx = f.file->private_data;
mutex_lock(&ctx->uring_lock);
ret = __io_uring_register(ctx, opcode, arg, nr_args);
mutex_unlock(&ctx->uring_lock);
trace_io_uring_register(ctx, opcode, ctx->nr_user_files, ctx->nr_user_bufs,
ctx->cq_ev_fd != NULL, ret);
out_fput:
fdput(f);
return ret;
}
static int __init io_uring_init(void)
{
#define __BUILD_BUG_VERIFY_ELEMENT(stype, eoffset, etype, ename) do { \
BUILD_BUG_ON(offsetof(stype, ename) != eoffset); \
BUILD_BUG_ON(sizeof(etype) != sizeof_field(stype, ename)); \
} while (0)
#define BUILD_BUG_SQE_ELEM(eoffset, etype, ename) \
__BUILD_BUG_VERIFY_ELEMENT(struct io_uring_sqe, eoffset, etype, ename)
BUILD_BUG_ON(sizeof(struct io_uring_sqe) != 64);
BUILD_BUG_SQE_ELEM(0, __u8, opcode);
BUILD_BUG_SQE_ELEM(1, __u8, flags);
BUILD_BUG_SQE_ELEM(2, __u16, ioprio);
BUILD_BUG_SQE_ELEM(4, __s32, fd);
BUILD_BUG_SQE_ELEM(8, __u64, off);
BUILD_BUG_SQE_ELEM(8, __u64, addr2);
BUILD_BUG_SQE_ELEM(16, __u64, addr);
BUILD_BUG_SQE_ELEM(16, __u64, splice_off_in);
BUILD_BUG_SQE_ELEM(24, __u32, len);
BUILD_BUG_SQE_ELEM(28, __kernel_rwf_t, rw_flags);
BUILD_BUG_SQE_ELEM(28, /* compat */ int, rw_flags);
BUILD_BUG_SQE_ELEM(28, /* compat */ __u32, rw_flags);
BUILD_BUG_SQE_ELEM(28, __u32, fsync_flags);
BUILD_BUG_SQE_ELEM(28, /* compat */ __u16, poll_events);
BUILD_BUG_SQE_ELEM(28, __u32, poll32_events);
BUILD_BUG_SQE_ELEM(28, __u32, sync_range_flags);
BUILD_BUG_SQE_ELEM(28, __u32, msg_flags);
BUILD_BUG_SQE_ELEM(28, __u32, timeout_flags);
BUILD_BUG_SQE_ELEM(28, __u32, accept_flags);
BUILD_BUG_SQE_ELEM(28, __u32, cancel_flags);
BUILD_BUG_SQE_ELEM(28, __u32, open_flags);
BUILD_BUG_SQE_ELEM(28, __u32, statx_flags);
BUILD_BUG_SQE_ELEM(28, __u32, fadvise_advice);
BUILD_BUG_SQE_ELEM(28, __u32, splice_flags);
BUILD_BUG_SQE_ELEM(32, __u64, user_data);
BUILD_BUG_SQE_ELEM(40, __u16, buf_index);
BUILD_BUG_SQE_ELEM(42, __u16, personality);
BUILD_BUG_SQE_ELEM(44, __s32, splice_fd_in);
BUILD_BUG_ON(ARRAY_SIZE(io_op_defs) != IORING_OP_LAST);
BUILD_BUG_ON(__REQ_F_LAST_BIT >= 8 * sizeof(int));
req_cachep = KMEM_CACHE(io_kiocb, SLAB_HWCACHE_ALIGN | SLAB_PANIC);
return 0;
};
__initcall(io_uring_init);