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![Shaohua Li](/assets/img/avatar_default.png)
lockdep reports a warnning. file_start_write/file_end_write only acquire/release the lock for regular files. So checking the files in aio side too. [ 453.532141] ------------[ cut here ]------------ [ 453.533011] WARNING: CPU: 1 PID: 1298 at ../kernel/locking/lockdep.c:3514 lock_release+0x434/0x670 [ 453.533011] DEBUG_LOCKS_WARN_ON(depth <= 0) [ 453.533011] Modules linked in: [ 453.533011] CPU: 1 PID: 1298 Comm: fio Not tainted 4.9.0+ #964 [ 453.533011] Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.9.0-1.fc24 04/01/2014 [ 453.533011] ffff8803a24b7a70 ffffffff8196cffb ffff8803a24b7ae8 0000000000000000 [ 453.533011] ffff8803a24b7ab8 ffffffff81091ee1 ffff8803a5dba700 00000dba00000008 [ 453.533011] ffffed0074496f59 ffff8803a5dbaf54 ffff8803ae0f8488 fffffffffffffdef [ 453.533011] Call Trace: [ 453.533011] [<ffffffff8196cffb>] dump_stack+0x67/0x9c [ 453.533011] [<ffffffff81091ee1>] __warn+0x111/0x130 [ 453.533011] [<ffffffff81091f97>] warn_slowpath_fmt+0x97/0xb0 [ 453.533011] [<ffffffff81091f00>] ? __warn+0x130/0x130 [ 453.533011] [<ffffffff8191b789>] ? blk_finish_plug+0x29/0x60 [ 453.533011] [<ffffffff811205d4>] lock_release+0x434/0x670 [ 453.533011] [<ffffffff8198af94>] ? import_single_range+0xd4/0x110 [ 453.533011] [<ffffffff81322195>] ? rw_verify_area+0x65/0x140 [ 453.533011] [<ffffffff813aa696>] ? aio_write+0x1f6/0x280 [ 453.533011] [<ffffffff813aa6c9>] aio_write+0x229/0x280 [ 453.533011] [<ffffffff813aa4a0>] ? aio_complete+0x640/0x640 [ 453.533011] [<ffffffff8111df20>] ? debug_check_no_locks_freed+0x1a0/0x1a0 [ 453.533011] [<ffffffff8114793a>] ? debug_lockdep_rcu_enabled.part.2+0x1a/0x30 [ 453.533011] [<ffffffff81147985>] ? debug_lockdep_rcu_enabled+0x35/0x40 [ 453.533011] [<ffffffff812a92be>] ? __might_fault+0x7e/0xf0 [ 453.533011] [<ffffffff813ac9bc>] do_io_submit+0x94c/0xb10 [ 453.533011] [<ffffffff813ac2ae>] ? do_io_submit+0x23e/0xb10 [ 453.533011] [<ffffffff813ac070>] ? SyS_io_destroy+0x270/0x270 [ 453.533011] [<ffffffff8111d7b3>] ? mark_held_locks+0x23/0xc0 [ 453.533011] [<ffffffff8100201a>] ? trace_hardirqs_on_thunk+0x1a/0x1c [ 453.533011] [<ffffffff813acb90>] SyS_io_submit+0x10/0x20 [ 453.533011] [<ffffffff824f96aa>] entry_SYSCALL_64_fastpath+0x18/0xad [ 453.533011] [<ffffffff81119190>] ? trace_hardirqs_off_caller+0xc0/0x110 [ 453.533011] ---[ end trace b2fbe664d1cc0082 ]--- Cc: Dmitry Monakhov <dmonakhov@openvz.org> Cc: Jan Kara <jack@suse.cz> Cc: Christoph Hellwig <hch@lst.de> Cc: Al Viro <viro@zeniv.linux.org.uk> Reviewed-by: Christoph Hellwig <hch@lst.de> Signed-off-by: Shaohua Li <shli@fb.com> Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
1858 lines
46 KiB
C
1858 lines
46 KiB
C
/*
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* An async IO implementation for Linux
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* Written by Benjamin LaHaise <bcrl@kvack.org>
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*
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* Implements an efficient asynchronous io interface.
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*
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* Copyright 2000, 2001, 2002 Red Hat, Inc. All Rights Reserved.
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*
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* See ../COPYING for licensing terms.
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*/
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#define pr_fmt(fmt) "%s: " fmt, __func__
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#include <linux/kernel.h>
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#include <linux/init.h>
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#include <linux/errno.h>
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#include <linux/time.h>
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#include <linux/aio_abi.h>
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#include <linux/export.h>
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#include <linux/syscalls.h>
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#include <linux/backing-dev.h>
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#include <linux/uio.h>
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#include <linux/sched.h>
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#include <linux/fs.h>
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#include <linux/file.h>
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#include <linux/mm.h>
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#include <linux/mman.h>
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#include <linux/mmu_context.h>
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#include <linux/percpu.h>
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#include <linux/slab.h>
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#include <linux/timer.h>
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#include <linux/aio.h>
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#include <linux/highmem.h>
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#include <linux/workqueue.h>
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#include <linux/security.h>
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#include <linux/eventfd.h>
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#include <linux/blkdev.h>
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#include <linux/compat.h>
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#include <linux/migrate.h>
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#include <linux/ramfs.h>
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#include <linux/percpu-refcount.h>
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#include <linux/mount.h>
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#include <asm/kmap_types.h>
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#include <linux/uaccess.h>
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#include "internal.h"
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#define AIO_RING_MAGIC 0xa10a10a1
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#define AIO_RING_COMPAT_FEATURES 1
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#define AIO_RING_INCOMPAT_FEATURES 0
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struct aio_ring {
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unsigned id; /* kernel internal index number */
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unsigned nr; /* number of io_events */
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unsigned head; /* Written to by userland or under ring_lock
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* mutex by aio_read_events_ring(). */
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unsigned tail;
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unsigned magic;
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unsigned compat_features;
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unsigned incompat_features;
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unsigned header_length; /* size of aio_ring */
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struct io_event io_events[0];
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}; /* 128 bytes + ring size */
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#define AIO_RING_PAGES 8
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struct kioctx_table {
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struct rcu_head rcu;
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unsigned nr;
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struct kioctx *table[];
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};
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struct kioctx_cpu {
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unsigned reqs_available;
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};
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struct ctx_rq_wait {
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struct completion comp;
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atomic_t count;
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};
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struct kioctx {
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struct percpu_ref users;
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atomic_t dead;
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struct percpu_ref reqs;
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unsigned long user_id;
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struct __percpu kioctx_cpu *cpu;
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/*
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* For percpu reqs_available, number of slots we move to/from global
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* counter at a time:
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*/
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unsigned req_batch;
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/*
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* This is what userspace passed to io_setup(), it's not used for
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* anything but counting against the global max_reqs quota.
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*
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* The real limit is nr_events - 1, which will be larger (see
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* aio_setup_ring())
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*/
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unsigned max_reqs;
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/* Size of ringbuffer, in units of struct io_event */
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unsigned nr_events;
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unsigned long mmap_base;
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unsigned long mmap_size;
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struct page **ring_pages;
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long nr_pages;
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struct work_struct free_work;
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/*
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* signals when all in-flight requests are done
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*/
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struct ctx_rq_wait *rq_wait;
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struct {
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/*
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* This counts the number of available slots in the ringbuffer,
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* so we avoid overflowing it: it's decremented (if positive)
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* when allocating a kiocb and incremented when the resulting
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* io_event is pulled off the ringbuffer.
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*
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* We batch accesses to it with a percpu version.
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*/
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atomic_t reqs_available;
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} ____cacheline_aligned_in_smp;
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struct {
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spinlock_t ctx_lock;
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struct list_head active_reqs; /* used for cancellation */
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} ____cacheline_aligned_in_smp;
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struct {
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struct mutex ring_lock;
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wait_queue_head_t wait;
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} ____cacheline_aligned_in_smp;
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struct {
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unsigned tail;
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unsigned completed_events;
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spinlock_t completion_lock;
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} ____cacheline_aligned_in_smp;
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struct page *internal_pages[AIO_RING_PAGES];
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struct file *aio_ring_file;
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unsigned id;
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};
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/*
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* We use ki_cancel == KIOCB_CANCELLED to indicate that a kiocb has been either
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* cancelled or completed (this makes a certain amount of sense because
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* successful cancellation - io_cancel() - does deliver the completion to
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* userspace).
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*
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* And since most things don't implement kiocb cancellation and we'd really like
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* kiocb completion to be lockless when possible, we use ki_cancel to
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* synchronize cancellation and completion - we only set it to KIOCB_CANCELLED
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* with xchg() or cmpxchg(), see batch_complete_aio() and kiocb_cancel().
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*/
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#define KIOCB_CANCELLED ((void *) (~0ULL))
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struct aio_kiocb {
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struct kiocb common;
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struct kioctx *ki_ctx;
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kiocb_cancel_fn *ki_cancel;
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struct iocb __user *ki_user_iocb; /* user's aiocb */
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__u64 ki_user_data; /* user's data for completion */
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struct list_head ki_list; /* the aio core uses this
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* for cancellation */
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/*
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* If the aio_resfd field of the userspace iocb is not zero,
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* this is the underlying eventfd context to deliver events to.
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*/
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struct eventfd_ctx *ki_eventfd;
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};
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/*------ sysctl variables----*/
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static DEFINE_SPINLOCK(aio_nr_lock);
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unsigned long aio_nr; /* current system wide number of aio requests */
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unsigned long aio_max_nr = 0x10000; /* system wide maximum number of aio requests */
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/*----end sysctl variables---*/
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static struct kmem_cache *kiocb_cachep;
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static struct kmem_cache *kioctx_cachep;
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static struct vfsmount *aio_mnt;
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static const struct file_operations aio_ring_fops;
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static const struct address_space_operations aio_ctx_aops;
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static struct file *aio_private_file(struct kioctx *ctx, loff_t nr_pages)
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{
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struct qstr this = QSTR_INIT("[aio]", 5);
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struct file *file;
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struct path path;
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struct inode *inode = alloc_anon_inode(aio_mnt->mnt_sb);
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if (IS_ERR(inode))
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return ERR_CAST(inode);
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inode->i_mapping->a_ops = &aio_ctx_aops;
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inode->i_mapping->private_data = ctx;
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inode->i_size = PAGE_SIZE * nr_pages;
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path.dentry = d_alloc_pseudo(aio_mnt->mnt_sb, &this);
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if (!path.dentry) {
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iput(inode);
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return ERR_PTR(-ENOMEM);
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}
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path.mnt = mntget(aio_mnt);
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d_instantiate(path.dentry, inode);
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file = alloc_file(&path, FMODE_READ | FMODE_WRITE, &aio_ring_fops);
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if (IS_ERR(file)) {
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path_put(&path);
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return file;
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}
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file->f_flags = O_RDWR;
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return file;
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}
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static struct dentry *aio_mount(struct file_system_type *fs_type,
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int flags, const char *dev_name, void *data)
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{
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static const struct dentry_operations ops = {
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.d_dname = simple_dname,
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};
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struct dentry *root = mount_pseudo(fs_type, "aio:", NULL, &ops,
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AIO_RING_MAGIC);
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if (!IS_ERR(root))
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root->d_sb->s_iflags |= SB_I_NOEXEC;
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return root;
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}
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/* aio_setup
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* Creates the slab caches used by the aio routines, panic on
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* failure as this is done early during the boot sequence.
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*/
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static int __init aio_setup(void)
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{
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static struct file_system_type aio_fs = {
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.name = "aio",
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.mount = aio_mount,
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.kill_sb = kill_anon_super,
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};
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aio_mnt = kern_mount(&aio_fs);
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if (IS_ERR(aio_mnt))
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panic("Failed to create aio fs mount.");
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kiocb_cachep = KMEM_CACHE(aio_kiocb, SLAB_HWCACHE_ALIGN|SLAB_PANIC);
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kioctx_cachep = KMEM_CACHE(kioctx,SLAB_HWCACHE_ALIGN|SLAB_PANIC);
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pr_debug("sizeof(struct page) = %zu\n", sizeof(struct page));
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return 0;
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}
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__initcall(aio_setup);
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static void put_aio_ring_file(struct kioctx *ctx)
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{
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struct file *aio_ring_file = ctx->aio_ring_file;
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struct address_space *i_mapping;
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if (aio_ring_file) {
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truncate_setsize(file_inode(aio_ring_file), 0);
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/* Prevent further access to the kioctx from migratepages */
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i_mapping = aio_ring_file->f_mapping;
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spin_lock(&i_mapping->private_lock);
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i_mapping->private_data = NULL;
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ctx->aio_ring_file = NULL;
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spin_unlock(&i_mapping->private_lock);
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fput(aio_ring_file);
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}
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}
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static void aio_free_ring(struct kioctx *ctx)
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{
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int i;
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/* Disconnect the kiotx from the ring file. This prevents future
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* accesses to the kioctx from page migration.
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*/
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put_aio_ring_file(ctx);
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for (i = 0; i < ctx->nr_pages; i++) {
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struct page *page;
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pr_debug("pid(%d) [%d] page->count=%d\n", current->pid, i,
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page_count(ctx->ring_pages[i]));
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page = ctx->ring_pages[i];
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if (!page)
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continue;
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ctx->ring_pages[i] = NULL;
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put_page(page);
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}
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if (ctx->ring_pages && ctx->ring_pages != ctx->internal_pages) {
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kfree(ctx->ring_pages);
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ctx->ring_pages = NULL;
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}
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}
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static int aio_ring_mremap(struct vm_area_struct *vma)
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{
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struct file *file = vma->vm_file;
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struct mm_struct *mm = vma->vm_mm;
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struct kioctx_table *table;
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int i, res = -EINVAL;
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spin_lock(&mm->ioctx_lock);
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rcu_read_lock();
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table = rcu_dereference(mm->ioctx_table);
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for (i = 0; i < table->nr; i++) {
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struct kioctx *ctx;
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ctx = table->table[i];
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if (ctx && ctx->aio_ring_file == file) {
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if (!atomic_read(&ctx->dead)) {
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ctx->user_id = ctx->mmap_base = vma->vm_start;
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res = 0;
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}
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break;
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}
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}
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rcu_read_unlock();
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spin_unlock(&mm->ioctx_lock);
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return res;
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}
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static const struct vm_operations_struct aio_ring_vm_ops = {
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.mremap = aio_ring_mremap,
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#if IS_ENABLED(CONFIG_MMU)
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.fault = filemap_fault,
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.map_pages = filemap_map_pages,
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.page_mkwrite = filemap_page_mkwrite,
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#endif
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};
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static int aio_ring_mmap(struct file *file, struct vm_area_struct *vma)
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{
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vma->vm_flags |= VM_DONTEXPAND;
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vma->vm_ops = &aio_ring_vm_ops;
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return 0;
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}
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static const struct file_operations aio_ring_fops = {
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.mmap = aio_ring_mmap,
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};
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#if IS_ENABLED(CONFIG_MIGRATION)
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static int aio_migratepage(struct address_space *mapping, struct page *new,
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struct page *old, enum migrate_mode mode)
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{
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struct kioctx *ctx;
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unsigned long flags;
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pgoff_t idx;
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int rc;
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rc = 0;
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/* mapping->private_lock here protects against the kioctx teardown. */
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spin_lock(&mapping->private_lock);
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ctx = mapping->private_data;
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if (!ctx) {
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rc = -EINVAL;
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goto out;
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}
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/* The ring_lock mutex. The prevents aio_read_events() from writing
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* to the ring's head, and prevents page migration from mucking in
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* a partially initialized kiotx.
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*/
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if (!mutex_trylock(&ctx->ring_lock)) {
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rc = -EAGAIN;
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goto out;
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}
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idx = old->index;
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if (idx < (pgoff_t)ctx->nr_pages) {
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/* Make sure the old page hasn't already been changed */
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if (ctx->ring_pages[idx] != old)
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rc = -EAGAIN;
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} else
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rc = -EINVAL;
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if (rc != 0)
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goto out_unlock;
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/* Writeback must be complete */
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BUG_ON(PageWriteback(old));
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get_page(new);
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rc = migrate_page_move_mapping(mapping, new, old, NULL, mode, 1);
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if (rc != MIGRATEPAGE_SUCCESS) {
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put_page(new);
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goto out_unlock;
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}
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/* Take completion_lock to prevent other writes to the ring buffer
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* while the old page is copied to the new. This prevents new
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* events from being lost.
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*/
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spin_lock_irqsave(&ctx->completion_lock, flags);
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migrate_page_copy(new, old);
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BUG_ON(ctx->ring_pages[idx] != old);
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ctx->ring_pages[idx] = new;
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spin_unlock_irqrestore(&ctx->completion_lock, flags);
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|
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/* The old page is no longer accessible. */
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put_page(old);
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out_unlock:
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mutex_unlock(&ctx->ring_lock);
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out:
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spin_unlock(&mapping->private_lock);
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return rc;
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}
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#endif
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|
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static const struct address_space_operations aio_ctx_aops = {
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.set_page_dirty = __set_page_dirty_no_writeback,
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#if IS_ENABLED(CONFIG_MIGRATION)
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.migratepage = aio_migratepage,
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#endif
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};
|
|
|
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static int aio_setup_ring(struct kioctx *ctx)
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{
|
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struct aio_ring *ring;
|
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unsigned nr_events = ctx->max_reqs;
|
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struct mm_struct *mm = current->mm;
|
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unsigned long size, unused;
|
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int nr_pages;
|
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int i;
|
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struct file *file;
|
|
|
|
/* Compensate for the ring buffer's head/tail overlap entry */
|
|
nr_events += 2; /* 1 is required, 2 for good luck */
|
|
|
|
size = sizeof(struct aio_ring);
|
|
size += sizeof(struct io_event) * nr_events;
|
|
|
|
nr_pages = PFN_UP(size);
|
|
if (nr_pages < 0)
|
|
return -EINVAL;
|
|
|
|
file = aio_private_file(ctx, nr_pages);
|
|
if (IS_ERR(file)) {
|
|
ctx->aio_ring_file = NULL;
|
|
return -ENOMEM;
|
|
}
|
|
|
|
ctx->aio_ring_file = file;
|
|
nr_events = (PAGE_SIZE * nr_pages - sizeof(struct aio_ring))
|
|
/ sizeof(struct io_event);
|
|
|
|
ctx->ring_pages = ctx->internal_pages;
|
|
if (nr_pages > AIO_RING_PAGES) {
|
|
ctx->ring_pages = kcalloc(nr_pages, sizeof(struct page *),
|
|
GFP_KERNEL);
|
|
if (!ctx->ring_pages) {
|
|
put_aio_ring_file(ctx);
|
|
return -ENOMEM;
|
|
}
|
|
}
|
|
|
|
for (i = 0; i < nr_pages; i++) {
|
|
struct page *page;
|
|
page = find_or_create_page(file->f_mapping,
|
|
i, GFP_HIGHUSER | __GFP_ZERO);
|
|
if (!page)
|
|
break;
|
|
pr_debug("pid(%d) page[%d]->count=%d\n",
|
|
current->pid, i, page_count(page));
|
|
SetPageUptodate(page);
|
|
unlock_page(page);
|
|
|
|
ctx->ring_pages[i] = page;
|
|
}
|
|
ctx->nr_pages = i;
|
|
|
|
if (unlikely(i != nr_pages)) {
|
|
aio_free_ring(ctx);
|
|
return -ENOMEM;
|
|
}
|
|
|
|
ctx->mmap_size = nr_pages * PAGE_SIZE;
|
|
pr_debug("attempting mmap of %lu bytes\n", ctx->mmap_size);
|
|
|
|
if (down_write_killable(&mm->mmap_sem)) {
|
|
ctx->mmap_size = 0;
|
|
aio_free_ring(ctx);
|
|
return -EINTR;
|
|
}
|
|
|
|
ctx->mmap_base = do_mmap_pgoff(ctx->aio_ring_file, 0, ctx->mmap_size,
|
|
PROT_READ | PROT_WRITE,
|
|
MAP_SHARED, 0, &unused);
|
|
up_write(&mm->mmap_sem);
|
|
if (IS_ERR((void *)ctx->mmap_base)) {
|
|
ctx->mmap_size = 0;
|
|
aio_free_ring(ctx);
|
|
return -ENOMEM;
|
|
}
|
|
|
|
pr_debug("mmap address: 0x%08lx\n", ctx->mmap_base);
|
|
|
|
ctx->user_id = ctx->mmap_base;
|
|
ctx->nr_events = nr_events; /* trusted copy */
|
|
|
|
ring = kmap_atomic(ctx->ring_pages[0]);
|
|
ring->nr = nr_events; /* user copy */
|
|
ring->id = ~0U;
|
|
ring->head = ring->tail = 0;
|
|
ring->magic = AIO_RING_MAGIC;
|
|
ring->compat_features = AIO_RING_COMPAT_FEATURES;
|
|
ring->incompat_features = AIO_RING_INCOMPAT_FEATURES;
|
|
ring->header_length = sizeof(struct aio_ring);
|
|
kunmap_atomic(ring);
|
|
flush_dcache_page(ctx->ring_pages[0]);
|
|
|
|
return 0;
|
|
}
|
|
|
|
#define AIO_EVENTS_PER_PAGE (PAGE_SIZE / sizeof(struct io_event))
|
|
#define AIO_EVENTS_FIRST_PAGE ((PAGE_SIZE - sizeof(struct aio_ring)) / sizeof(struct io_event))
|
|
#define AIO_EVENTS_OFFSET (AIO_EVENTS_PER_PAGE - AIO_EVENTS_FIRST_PAGE)
|
|
|
|
void kiocb_set_cancel_fn(struct kiocb *iocb, kiocb_cancel_fn *cancel)
|
|
{
|
|
struct aio_kiocb *req = container_of(iocb, struct aio_kiocb, common);
|
|
struct kioctx *ctx = req->ki_ctx;
|
|
unsigned long flags;
|
|
|
|
spin_lock_irqsave(&ctx->ctx_lock, flags);
|
|
|
|
if (!req->ki_list.next)
|
|
list_add(&req->ki_list, &ctx->active_reqs);
|
|
|
|
req->ki_cancel = cancel;
|
|
|
|
spin_unlock_irqrestore(&ctx->ctx_lock, flags);
|
|
}
|
|
EXPORT_SYMBOL(kiocb_set_cancel_fn);
|
|
|
|
static int kiocb_cancel(struct aio_kiocb *kiocb)
|
|
{
|
|
kiocb_cancel_fn *old, *cancel;
|
|
|
|
/*
|
|
* Don't want to set kiocb->ki_cancel = KIOCB_CANCELLED unless it
|
|
* actually has a cancel function, hence the cmpxchg()
|
|
*/
|
|
|
|
cancel = ACCESS_ONCE(kiocb->ki_cancel);
|
|
do {
|
|
if (!cancel || cancel == KIOCB_CANCELLED)
|
|
return -EINVAL;
|
|
|
|
old = cancel;
|
|
cancel = cmpxchg(&kiocb->ki_cancel, old, KIOCB_CANCELLED);
|
|
} while (cancel != old);
|
|
|
|
return cancel(&kiocb->common);
|
|
}
|
|
|
|
static void free_ioctx(struct work_struct *work)
|
|
{
|
|
struct kioctx *ctx = container_of(work, struct kioctx, free_work);
|
|
|
|
pr_debug("freeing %p\n", ctx);
|
|
|
|
aio_free_ring(ctx);
|
|
free_percpu(ctx->cpu);
|
|
percpu_ref_exit(&ctx->reqs);
|
|
percpu_ref_exit(&ctx->users);
|
|
kmem_cache_free(kioctx_cachep, ctx);
|
|
}
|
|
|
|
static void free_ioctx_reqs(struct percpu_ref *ref)
|
|
{
|
|
struct kioctx *ctx = container_of(ref, struct kioctx, reqs);
|
|
|
|
/* At this point we know that there are no any in-flight requests */
|
|
if (ctx->rq_wait && atomic_dec_and_test(&ctx->rq_wait->count))
|
|
complete(&ctx->rq_wait->comp);
|
|
|
|
INIT_WORK(&ctx->free_work, free_ioctx);
|
|
schedule_work(&ctx->free_work);
|
|
}
|
|
|
|
/*
|
|
* When this function runs, the kioctx has been removed from the "hash table"
|
|
* and ctx->users has dropped to 0, so we know no more kiocbs can be submitted -
|
|
* now it's safe to cancel any that need to be.
|
|
*/
|
|
static void free_ioctx_users(struct percpu_ref *ref)
|
|
{
|
|
struct kioctx *ctx = container_of(ref, struct kioctx, users);
|
|
struct aio_kiocb *req;
|
|
|
|
spin_lock_irq(&ctx->ctx_lock);
|
|
|
|
while (!list_empty(&ctx->active_reqs)) {
|
|
req = list_first_entry(&ctx->active_reqs,
|
|
struct aio_kiocb, ki_list);
|
|
|
|
list_del_init(&req->ki_list);
|
|
kiocb_cancel(req);
|
|
}
|
|
|
|
spin_unlock_irq(&ctx->ctx_lock);
|
|
|
|
percpu_ref_kill(&ctx->reqs);
|
|
percpu_ref_put(&ctx->reqs);
|
|
}
|
|
|
|
static int ioctx_add_table(struct kioctx *ctx, struct mm_struct *mm)
|
|
{
|
|
unsigned i, new_nr;
|
|
struct kioctx_table *table, *old;
|
|
struct aio_ring *ring;
|
|
|
|
spin_lock(&mm->ioctx_lock);
|
|
table = rcu_dereference_raw(mm->ioctx_table);
|
|
|
|
while (1) {
|
|
if (table)
|
|
for (i = 0; i < table->nr; i++)
|
|
if (!table->table[i]) {
|
|
ctx->id = i;
|
|
table->table[i] = ctx;
|
|
spin_unlock(&mm->ioctx_lock);
|
|
|
|
/* While kioctx setup is in progress,
|
|
* we are protected from page migration
|
|
* changes ring_pages by ->ring_lock.
|
|
*/
|
|
ring = kmap_atomic(ctx->ring_pages[0]);
|
|
ring->id = ctx->id;
|
|
kunmap_atomic(ring);
|
|
return 0;
|
|
}
|
|
|
|
new_nr = (table ? table->nr : 1) * 4;
|
|
spin_unlock(&mm->ioctx_lock);
|
|
|
|
table = kzalloc(sizeof(*table) + sizeof(struct kioctx *) *
|
|
new_nr, GFP_KERNEL);
|
|
if (!table)
|
|
return -ENOMEM;
|
|
|
|
table->nr = new_nr;
|
|
|
|
spin_lock(&mm->ioctx_lock);
|
|
old = rcu_dereference_raw(mm->ioctx_table);
|
|
|
|
if (!old) {
|
|
rcu_assign_pointer(mm->ioctx_table, table);
|
|
} else if (table->nr > old->nr) {
|
|
memcpy(table->table, old->table,
|
|
old->nr * sizeof(struct kioctx *));
|
|
|
|
rcu_assign_pointer(mm->ioctx_table, table);
|
|
kfree_rcu(old, rcu);
|
|
} else {
|
|
kfree(table);
|
|
table = old;
|
|
}
|
|
}
|
|
}
|
|
|
|
static void aio_nr_sub(unsigned nr)
|
|
{
|
|
spin_lock(&aio_nr_lock);
|
|
if (WARN_ON(aio_nr - nr > aio_nr))
|
|
aio_nr = 0;
|
|
else
|
|
aio_nr -= nr;
|
|
spin_unlock(&aio_nr_lock);
|
|
}
|
|
|
|
/* ioctx_alloc
|
|
* Allocates and initializes an ioctx. Returns an ERR_PTR if it failed.
|
|
*/
|
|
static struct kioctx *ioctx_alloc(unsigned nr_events)
|
|
{
|
|
struct mm_struct *mm = current->mm;
|
|
struct kioctx *ctx;
|
|
int err = -ENOMEM;
|
|
|
|
/*
|
|
* We keep track of the number of available ringbuffer slots, to prevent
|
|
* overflow (reqs_available), and we also use percpu counters for this.
|
|
*
|
|
* So since up to half the slots might be on other cpu's percpu counters
|
|
* and unavailable, double nr_events so userspace sees what they
|
|
* expected: additionally, we move req_batch slots to/from percpu
|
|
* counters at a time, so make sure that isn't 0:
|
|
*/
|
|
nr_events = max(nr_events, num_possible_cpus() * 4);
|
|
nr_events *= 2;
|
|
|
|
/* Prevent overflows */
|
|
if (nr_events > (0x10000000U / sizeof(struct io_event))) {
|
|
pr_debug("ENOMEM: nr_events too high\n");
|
|
return ERR_PTR(-EINVAL);
|
|
}
|
|
|
|
if (!nr_events || (unsigned long)nr_events > (aio_max_nr * 2UL))
|
|
return ERR_PTR(-EAGAIN);
|
|
|
|
ctx = kmem_cache_zalloc(kioctx_cachep, GFP_KERNEL);
|
|
if (!ctx)
|
|
return ERR_PTR(-ENOMEM);
|
|
|
|
ctx->max_reqs = nr_events;
|
|
|
|
spin_lock_init(&ctx->ctx_lock);
|
|
spin_lock_init(&ctx->completion_lock);
|
|
mutex_init(&ctx->ring_lock);
|
|
/* Protect against page migration throughout kiotx setup by keeping
|
|
* the ring_lock mutex held until setup is complete. */
|
|
mutex_lock(&ctx->ring_lock);
|
|
init_waitqueue_head(&ctx->wait);
|
|
|
|
INIT_LIST_HEAD(&ctx->active_reqs);
|
|
|
|
if (percpu_ref_init(&ctx->users, free_ioctx_users, 0, GFP_KERNEL))
|
|
goto err;
|
|
|
|
if (percpu_ref_init(&ctx->reqs, free_ioctx_reqs, 0, GFP_KERNEL))
|
|
goto err;
|
|
|
|
ctx->cpu = alloc_percpu(struct kioctx_cpu);
|
|
if (!ctx->cpu)
|
|
goto err;
|
|
|
|
err = aio_setup_ring(ctx);
|
|
if (err < 0)
|
|
goto err;
|
|
|
|
atomic_set(&ctx->reqs_available, ctx->nr_events - 1);
|
|
ctx->req_batch = (ctx->nr_events - 1) / (num_possible_cpus() * 4);
|
|
if (ctx->req_batch < 1)
|
|
ctx->req_batch = 1;
|
|
|
|
/* limit the number of system wide aios */
|
|
spin_lock(&aio_nr_lock);
|
|
if (aio_nr + nr_events > (aio_max_nr * 2UL) ||
|
|
aio_nr + nr_events < aio_nr) {
|
|
spin_unlock(&aio_nr_lock);
|
|
err = -EAGAIN;
|
|
goto err_ctx;
|
|
}
|
|
aio_nr += ctx->max_reqs;
|
|
spin_unlock(&aio_nr_lock);
|
|
|
|
percpu_ref_get(&ctx->users); /* io_setup() will drop this ref */
|
|
percpu_ref_get(&ctx->reqs); /* free_ioctx_users() will drop this */
|
|
|
|
err = ioctx_add_table(ctx, mm);
|
|
if (err)
|
|
goto err_cleanup;
|
|
|
|
/* Release the ring_lock mutex now that all setup is complete. */
|
|
mutex_unlock(&ctx->ring_lock);
|
|
|
|
pr_debug("allocated ioctx %p[%ld]: mm=%p mask=0x%x\n",
|
|
ctx, ctx->user_id, mm, ctx->nr_events);
|
|
return ctx;
|
|
|
|
err_cleanup:
|
|
aio_nr_sub(ctx->max_reqs);
|
|
err_ctx:
|
|
atomic_set(&ctx->dead, 1);
|
|
if (ctx->mmap_size)
|
|
vm_munmap(ctx->mmap_base, ctx->mmap_size);
|
|
aio_free_ring(ctx);
|
|
err:
|
|
mutex_unlock(&ctx->ring_lock);
|
|
free_percpu(ctx->cpu);
|
|
percpu_ref_exit(&ctx->reqs);
|
|
percpu_ref_exit(&ctx->users);
|
|
kmem_cache_free(kioctx_cachep, ctx);
|
|
pr_debug("error allocating ioctx %d\n", err);
|
|
return ERR_PTR(err);
|
|
}
|
|
|
|
/* kill_ioctx
|
|
* Cancels all outstanding aio requests on an aio context. Used
|
|
* when the processes owning a context have all exited to encourage
|
|
* the rapid destruction of the kioctx.
|
|
*/
|
|
static int kill_ioctx(struct mm_struct *mm, struct kioctx *ctx,
|
|
struct ctx_rq_wait *wait)
|
|
{
|
|
struct kioctx_table *table;
|
|
|
|
spin_lock(&mm->ioctx_lock);
|
|
if (atomic_xchg(&ctx->dead, 1)) {
|
|
spin_unlock(&mm->ioctx_lock);
|
|
return -EINVAL;
|
|
}
|
|
|
|
table = rcu_dereference_raw(mm->ioctx_table);
|
|
WARN_ON(ctx != table->table[ctx->id]);
|
|
table->table[ctx->id] = NULL;
|
|
spin_unlock(&mm->ioctx_lock);
|
|
|
|
/* percpu_ref_kill() will do the necessary call_rcu() */
|
|
wake_up_all(&ctx->wait);
|
|
|
|
/*
|
|
* It'd be more correct to do this in free_ioctx(), after all
|
|
* the outstanding kiocbs have finished - but by then io_destroy
|
|
* has already returned, so io_setup() could potentially return
|
|
* -EAGAIN with no ioctxs actually in use (as far as userspace
|
|
* could tell).
|
|
*/
|
|
aio_nr_sub(ctx->max_reqs);
|
|
|
|
if (ctx->mmap_size)
|
|
vm_munmap(ctx->mmap_base, ctx->mmap_size);
|
|
|
|
ctx->rq_wait = wait;
|
|
percpu_ref_kill(&ctx->users);
|
|
return 0;
|
|
}
|
|
|
|
/*
|
|
* exit_aio: called when the last user of mm goes away. At this point, there is
|
|
* no way for any new requests to be submited or any of the io_* syscalls to be
|
|
* called on the context.
|
|
*
|
|
* There may be outstanding kiocbs, but free_ioctx() will explicitly wait on
|
|
* them.
|
|
*/
|
|
void exit_aio(struct mm_struct *mm)
|
|
{
|
|
struct kioctx_table *table = rcu_dereference_raw(mm->ioctx_table);
|
|
struct ctx_rq_wait wait;
|
|
int i, skipped;
|
|
|
|
if (!table)
|
|
return;
|
|
|
|
atomic_set(&wait.count, table->nr);
|
|
init_completion(&wait.comp);
|
|
|
|
skipped = 0;
|
|
for (i = 0; i < table->nr; ++i) {
|
|
struct kioctx *ctx = table->table[i];
|
|
|
|
if (!ctx) {
|
|
skipped++;
|
|
continue;
|
|
}
|
|
|
|
/*
|
|
* We don't need to bother with munmap() here - exit_mmap(mm)
|
|
* is coming and it'll unmap everything. And we simply can't,
|
|
* this is not necessarily our ->mm.
|
|
* Since kill_ioctx() uses non-zero ->mmap_size as indicator
|
|
* that it needs to unmap the area, just set it to 0.
|
|
*/
|
|
ctx->mmap_size = 0;
|
|
kill_ioctx(mm, ctx, &wait);
|
|
}
|
|
|
|
if (!atomic_sub_and_test(skipped, &wait.count)) {
|
|
/* Wait until all IO for the context are done. */
|
|
wait_for_completion(&wait.comp);
|
|
}
|
|
|
|
RCU_INIT_POINTER(mm->ioctx_table, NULL);
|
|
kfree(table);
|
|
}
|
|
|
|
static void put_reqs_available(struct kioctx *ctx, unsigned nr)
|
|
{
|
|
struct kioctx_cpu *kcpu;
|
|
unsigned long flags;
|
|
|
|
local_irq_save(flags);
|
|
kcpu = this_cpu_ptr(ctx->cpu);
|
|
kcpu->reqs_available += nr;
|
|
|
|
while (kcpu->reqs_available >= ctx->req_batch * 2) {
|
|
kcpu->reqs_available -= ctx->req_batch;
|
|
atomic_add(ctx->req_batch, &ctx->reqs_available);
|
|
}
|
|
|
|
local_irq_restore(flags);
|
|
}
|
|
|
|
static bool get_reqs_available(struct kioctx *ctx)
|
|
{
|
|
struct kioctx_cpu *kcpu;
|
|
bool ret = false;
|
|
unsigned long flags;
|
|
|
|
local_irq_save(flags);
|
|
kcpu = this_cpu_ptr(ctx->cpu);
|
|
if (!kcpu->reqs_available) {
|
|
int old, avail = atomic_read(&ctx->reqs_available);
|
|
|
|
do {
|
|
if (avail < ctx->req_batch)
|
|
goto out;
|
|
|
|
old = avail;
|
|
avail = atomic_cmpxchg(&ctx->reqs_available,
|
|
avail, avail - ctx->req_batch);
|
|
} while (avail != old);
|
|
|
|
kcpu->reqs_available += ctx->req_batch;
|
|
}
|
|
|
|
ret = true;
|
|
kcpu->reqs_available--;
|
|
out:
|
|
local_irq_restore(flags);
|
|
return ret;
|
|
}
|
|
|
|
/* refill_reqs_available
|
|
* Updates the reqs_available reference counts used for tracking the
|
|
* number of free slots in the completion ring. This can be called
|
|
* from aio_complete() (to optimistically update reqs_available) or
|
|
* from aio_get_req() (the we're out of events case). It must be
|
|
* called holding ctx->completion_lock.
|
|
*/
|
|
static void refill_reqs_available(struct kioctx *ctx, unsigned head,
|
|
unsigned tail)
|
|
{
|
|
unsigned events_in_ring, completed;
|
|
|
|
/* Clamp head since userland can write to it. */
|
|
head %= ctx->nr_events;
|
|
if (head <= tail)
|
|
events_in_ring = tail - head;
|
|
else
|
|
events_in_ring = ctx->nr_events - (head - tail);
|
|
|
|
completed = ctx->completed_events;
|
|
if (events_in_ring < completed)
|
|
completed -= events_in_ring;
|
|
else
|
|
completed = 0;
|
|
|
|
if (!completed)
|
|
return;
|
|
|
|
ctx->completed_events -= completed;
|
|
put_reqs_available(ctx, completed);
|
|
}
|
|
|
|
/* user_refill_reqs_available
|
|
* Called to refill reqs_available when aio_get_req() encounters an
|
|
* out of space in the completion ring.
|
|
*/
|
|
static void user_refill_reqs_available(struct kioctx *ctx)
|
|
{
|
|
spin_lock_irq(&ctx->completion_lock);
|
|
if (ctx->completed_events) {
|
|
struct aio_ring *ring;
|
|
unsigned head;
|
|
|
|
/* Access of ring->head may race with aio_read_events_ring()
|
|
* here, but that's okay since whether we read the old version
|
|
* or the new version, and either will be valid. The important
|
|
* part is that head cannot pass tail since we prevent
|
|
* aio_complete() from updating tail by holding
|
|
* ctx->completion_lock. Even if head is invalid, the check
|
|
* against ctx->completed_events below will make sure we do the
|
|
* safe/right thing.
|
|
*/
|
|
ring = kmap_atomic(ctx->ring_pages[0]);
|
|
head = ring->head;
|
|
kunmap_atomic(ring);
|
|
|
|
refill_reqs_available(ctx, head, ctx->tail);
|
|
}
|
|
|
|
spin_unlock_irq(&ctx->completion_lock);
|
|
}
|
|
|
|
/* aio_get_req
|
|
* Allocate a slot for an aio request.
|
|
* Returns NULL if no requests are free.
|
|
*/
|
|
static inline struct aio_kiocb *aio_get_req(struct kioctx *ctx)
|
|
{
|
|
struct aio_kiocb *req;
|
|
|
|
if (!get_reqs_available(ctx)) {
|
|
user_refill_reqs_available(ctx);
|
|
if (!get_reqs_available(ctx))
|
|
return NULL;
|
|
}
|
|
|
|
req = kmem_cache_alloc(kiocb_cachep, GFP_KERNEL|__GFP_ZERO);
|
|
if (unlikely(!req))
|
|
goto out_put;
|
|
|
|
percpu_ref_get(&ctx->reqs);
|
|
|
|
req->ki_ctx = ctx;
|
|
return req;
|
|
out_put:
|
|
put_reqs_available(ctx, 1);
|
|
return NULL;
|
|
}
|
|
|
|
static void kiocb_free(struct aio_kiocb *req)
|
|
{
|
|
if (req->common.ki_filp)
|
|
fput(req->common.ki_filp);
|
|
if (req->ki_eventfd != NULL)
|
|
eventfd_ctx_put(req->ki_eventfd);
|
|
kmem_cache_free(kiocb_cachep, req);
|
|
}
|
|
|
|
static struct kioctx *lookup_ioctx(unsigned long ctx_id)
|
|
{
|
|
struct aio_ring __user *ring = (void __user *)ctx_id;
|
|
struct mm_struct *mm = current->mm;
|
|
struct kioctx *ctx, *ret = NULL;
|
|
struct kioctx_table *table;
|
|
unsigned id;
|
|
|
|
if (get_user(id, &ring->id))
|
|
return NULL;
|
|
|
|
rcu_read_lock();
|
|
table = rcu_dereference(mm->ioctx_table);
|
|
|
|
if (!table || id >= table->nr)
|
|
goto out;
|
|
|
|
ctx = table->table[id];
|
|
if (ctx && ctx->user_id == ctx_id) {
|
|
percpu_ref_get(&ctx->users);
|
|
ret = ctx;
|
|
}
|
|
out:
|
|
rcu_read_unlock();
|
|
return ret;
|
|
}
|
|
|
|
/* aio_complete
|
|
* Called when the io request on the given iocb is complete.
|
|
*/
|
|
static void aio_complete(struct kiocb *kiocb, long res, long res2)
|
|
{
|
|
struct aio_kiocb *iocb = container_of(kiocb, struct aio_kiocb, common);
|
|
struct kioctx *ctx = iocb->ki_ctx;
|
|
struct aio_ring *ring;
|
|
struct io_event *ev_page, *event;
|
|
unsigned tail, pos, head;
|
|
unsigned long flags;
|
|
|
|
if (kiocb->ki_flags & IOCB_WRITE) {
|
|
struct file *file = kiocb->ki_filp;
|
|
|
|
/*
|
|
* Tell lockdep we inherited freeze protection from submission
|
|
* thread.
|
|
*/
|
|
if (S_ISREG(file_inode(file)->i_mode))
|
|
__sb_writers_acquired(file_inode(file)->i_sb, SB_FREEZE_WRITE);
|
|
file_end_write(file);
|
|
}
|
|
|
|
/*
|
|
* Special case handling for sync iocbs:
|
|
* - events go directly into the iocb for fast handling
|
|
* - the sync task with the iocb in its stack holds the single iocb
|
|
* ref, no other paths have a way to get another ref
|
|
* - the sync task helpfully left a reference to itself in the iocb
|
|
*/
|
|
BUG_ON(is_sync_kiocb(kiocb));
|
|
|
|
if (iocb->ki_list.next) {
|
|
unsigned long flags;
|
|
|
|
spin_lock_irqsave(&ctx->ctx_lock, flags);
|
|
list_del(&iocb->ki_list);
|
|
spin_unlock_irqrestore(&ctx->ctx_lock, flags);
|
|
}
|
|
|
|
/*
|
|
* Add a completion event to the ring buffer. Must be done holding
|
|
* ctx->completion_lock to prevent other code from messing with the tail
|
|
* pointer since we might be called from irq context.
|
|
*/
|
|
spin_lock_irqsave(&ctx->completion_lock, flags);
|
|
|
|
tail = ctx->tail;
|
|
pos = tail + AIO_EVENTS_OFFSET;
|
|
|
|
if (++tail >= ctx->nr_events)
|
|
tail = 0;
|
|
|
|
ev_page = kmap_atomic(ctx->ring_pages[pos / AIO_EVENTS_PER_PAGE]);
|
|
event = ev_page + pos % AIO_EVENTS_PER_PAGE;
|
|
|
|
event->obj = (u64)(unsigned long)iocb->ki_user_iocb;
|
|
event->data = iocb->ki_user_data;
|
|
event->res = res;
|
|
event->res2 = res2;
|
|
|
|
kunmap_atomic(ev_page);
|
|
flush_dcache_page(ctx->ring_pages[pos / AIO_EVENTS_PER_PAGE]);
|
|
|
|
pr_debug("%p[%u]: %p: %p %Lx %lx %lx\n",
|
|
ctx, tail, iocb, iocb->ki_user_iocb, iocb->ki_user_data,
|
|
res, res2);
|
|
|
|
/* after flagging the request as done, we
|
|
* must never even look at it again
|
|
*/
|
|
smp_wmb(); /* make event visible before updating tail */
|
|
|
|
ctx->tail = tail;
|
|
|
|
ring = kmap_atomic(ctx->ring_pages[0]);
|
|
head = ring->head;
|
|
ring->tail = tail;
|
|
kunmap_atomic(ring);
|
|
flush_dcache_page(ctx->ring_pages[0]);
|
|
|
|
ctx->completed_events++;
|
|
if (ctx->completed_events > 1)
|
|
refill_reqs_available(ctx, head, tail);
|
|
spin_unlock_irqrestore(&ctx->completion_lock, flags);
|
|
|
|
pr_debug("added to ring %p at [%u]\n", iocb, tail);
|
|
|
|
/*
|
|
* Check if the user asked us to deliver the result through an
|
|
* eventfd. The eventfd_signal() function is safe to be called
|
|
* from IRQ context.
|
|
*/
|
|
if (iocb->ki_eventfd != NULL)
|
|
eventfd_signal(iocb->ki_eventfd, 1);
|
|
|
|
/* everything turned out well, dispose of the aiocb. */
|
|
kiocb_free(iocb);
|
|
|
|
/*
|
|
* We have to order our ring_info tail store above and test
|
|
* of the wait list below outside the wait lock. This is
|
|
* like in wake_up_bit() where clearing a bit has to be
|
|
* ordered with the unlocked test.
|
|
*/
|
|
smp_mb();
|
|
|
|
if (waitqueue_active(&ctx->wait))
|
|
wake_up(&ctx->wait);
|
|
|
|
percpu_ref_put(&ctx->reqs);
|
|
}
|
|
|
|
/* aio_read_events_ring
|
|
* Pull an event off of the ioctx's event ring. Returns the number of
|
|
* events fetched
|
|
*/
|
|
static long aio_read_events_ring(struct kioctx *ctx,
|
|
struct io_event __user *event, long nr)
|
|
{
|
|
struct aio_ring *ring;
|
|
unsigned head, tail, pos;
|
|
long ret = 0;
|
|
int copy_ret;
|
|
|
|
/*
|
|
* The mutex can block and wake us up and that will cause
|
|
* wait_event_interruptible_hrtimeout() to schedule without sleeping
|
|
* and repeat. This should be rare enough that it doesn't cause
|
|
* peformance issues. See the comment in read_events() for more detail.
|
|
*/
|
|
sched_annotate_sleep();
|
|
mutex_lock(&ctx->ring_lock);
|
|
|
|
/* Access to ->ring_pages here is protected by ctx->ring_lock. */
|
|
ring = kmap_atomic(ctx->ring_pages[0]);
|
|
head = ring->head;
|
|
tail = ring->tail;
|
|
kunmap_atomic(ring);
|
|
|
|
/*
|
|
* Ensure that once we've read the current tail pointer, that
|
|
* we also see the events that were stored up to the tail.
|
|
*/
|
|
smp_rmb();
|
|
|
|
pr_debug("h%u t%u m%u\n", head, tail, ctx->nr_events);
|
|
|
|
if (head == tail)
|
|
goto out;
|
|
|
|
head %= ctx->nr_events;
|
|
tail %= ctx->nr_events;
|
|
|
|
while (ret < nr) {
|
|
long avail;
|
|
struct io_event *ev;
|
|
struct page *page;
|
|
|
|
avail = (head <= tail ? tail : ctx->nr_events) - head;
|
|
if (head == tail)
|
|
break;
|
|
|
|
avail = min(avail, nr - ret);
|
|
avail = min_t(long, avail, AIO_EVENTS_PER_PAGE -
|
|
((head + AIO_EVENTS_OFFSET) % AIO_EVENTS_PER_PAGE));
|
|
|
|
pos = head + AIO_EVENTS_OFFSET;
|
|
page = ctx->ring_pages[pos / AIO_EVENTS_PER_PAGE];
|
|
pos %= AIO_EVENTS_PER_PAGE;
|
|
|
|
ev = kmap(page);
|
|
copy_ret = copy_to_user(event + ret, ev + pos,
|
|
sizeof(*ev) * avail);
|
|
kunmap(page);
|
|
|
|
if (unlikely(copy_ret)) {
|
|
ret = -EFAULT;
|
|
goto out;
|
|
}
|
|
|
|
ret += avail;
|
|
head += avail;
|
|
head %= ctx->nr_events;
|
|
}
|
|
|
|
ring = kmap_atomic(ctx->ring_pages[0]);
|
|
ring->head = head;
|
|
kunmap_atomic(ring);
|
|
flush_dcache_page(ctx->ring_pages[0]);
|
|
|
|
pr_debug("%li h%u t%u\n", ret, head, tail);
|
|
out:
|
|
mutex_unlock(&ctx->ring_lock);
|
|
|
|
return ret;
|
|
}
|
|
|
|
static bool aio_read_events(struct kioctx *ctx, long min_nr, long nr,
|
|
struct io_event __user *event, long *i)
|
|
{
|
|
long ret = aio_read_events_ring(ctx, event + *i, nr - *i);
|
|
|
|
if (ret > 0)
|
|
*i += ret;
|
|
|
|
if (unlikely(atomic_read(&ctx->dead)))
|
|
ret = -EINVAL;
|
|
|
|
if (!*i)
|
|
*i = ret;
|
|
|
|
return ret < 0 || *i >= min_nr;
|
|
}
|
|
|
|
static long read_events(struct kioctx *ctx, long min_nr, long nr,
|
|
struct io_event __user *event,
|
|
struct timespec __user *timeout)
|
|
{
|
|
ktime_t until = KTIME_MAX;
|
|
long ret = 0;
|
|
|
|
if (timeout) {
|
|
struct timespec ts;
|
|
|
|
if (unlikely(copy_from_user(&ts, timeout, sizeof(ts))))
|
|
return -EFAULT;
|
|
|
|
until = timespec_to_ktime(ts);
|
|
}
|
|
|
|
/*
|
|
* Note that aio_read_events() is being called as the conditional - i.e.
|
|
* we're calling it after prepare_to_wait() has set task state to
|
|
* TASK_INTERRUPTIBLE.
|
|
*
|
|
* But aio_read_events() can block, and if it blocks it's going to flip
|
|
* the task state back to TASK_RUNNING.
|
|
*
|
|
* This should be ok, provided it doesn't flip the state back to
|
|
* TASK_RUNNING and return 0 too much - that causes us to spin. That
|
|
* will only happen if the mutex_lock() call blocks, and we then find
|
|
* the ringbuffer empty. So in practice we should be ok, but it's
|
|
* something to be aware of when touching this code.
|
|
*/
|
|
if (until == 0)
|
|
aio_read_events(ctx, min_nr, nr, event, &ret);
|
|
else
|
|
wait_event_interruptible_hrtimeout(ctx->wait,
|
|
aio_read_events(ctx, min_nr, nr, event, &ret),
|
|
until);
|
|
|
|
if (!ret && signal_pending(current))
|
|
ret = -EINTR;
|
|
|
|
return ret;
|
|
}
|
|
|
|
/* sys_io_setup:
|
|
* Create an aio_context capable of receiving at least nr_events.
|
|
* ctxp must not point to an aio_context that already exists, and
|
|
* must be initialized to 0 prior to the call. On successful
|
|
* creation of the aio_context, *ctxp is filled in with the resulting
|
|
* handle. May fail with -EINVAL if *ctxp is not initialized,
|
|
* if the specified nr_events exceeds internal limits. May fail
|
|
* with -EAGAIN if the specified nr_events exceeds the user's limit
|
|
* of available events. May fail with -ENOMEM if insufficient kernel
|
|
* resources are available. May fail with -EFAULT if an invalid
|
|
* pointer is passed for ctxp. Will fail with -ENOSYS if not
|
|
* implemented.
|
|
*/
|
|
SYSCALL_DEFINE2(io_setup, unsigned, nr_events, aio_context_t __user *, ctxp)
|
|
{
|
|
struct kioctx *ioctx = NULL;
|
|
unsigned long ctx;
|
|
long ret;
|
|
|
|
ret = get_user(ctx, ctxp);
|
|
if (unlikely(ret))
|
|
goto out;
|
|
|
|
ret = -EINVAL;
|
|
if (unlikely(ctx || nr_events == 0)) {
|
|
pr_debug("EINVAL: ctx %lu nr_events %u\n",
|
|
ctx, nr_events);
|
|
goto out;
|
|
}
|
|
|
|
ioctx = ioctx_alloc(nr_events);
|
|
ret = PTR_ERR(ioctx);
|
|
if (!IS_ERR(ioctx)) {
|
|
ret = put_user(ioctx->user_id, ctxp);
|
|
if (ret)
|
|
kill_ioctx(current->mm, ioctx, NULL);
|
|
percpu_ref_put(&ioctx->users);
|
|
}
|
|
|
|
out:
|
|
return ret;
|
|
}
|
|
|
|
#ifdef CONFIG_COMPAT
|
|
COMPAT_SYSCALL_DEFINE2(io_setup, unsigned, nr_events, u32 __user *, ctx32p)
|
|
{
|
|
struct kioctx *ioctx = NULL;
|
|
unsigned long ctx;
|
|
long ret;
|
|
|
|
ret = get_user(ctx, ctx32p);
|
|
if (unlikely(ret))
|
|
goto out;
|
|
|
|
ret = -EINVAL;
|
|
if (unlikely(ctx || nr_events == 0)) {
|
|
pr_debug("EINVAL: ctx %lu nr_events %u\n",
|
|
ctx, nr_events);
|
|
goto out;
|
|
}
|
|
|
|
ioctx = ioctx_alloc(nr_events);
|
|
ret = PTR_ERR(ioctx);
|
|
if (!IS_ERR(ioctx)) {
|
|
/* truncating is ok because it's a user address */
|
|
ret = put_user((u32)ioctx->user_id, ctx32p);
|
|
if (ret)
|
|
kill_ioctx(current->mm, ioctx, NULL);
|
|
percpu_ref_put(&ioctx->users);
|
|
}
|
|
|
|
out:
|
|
return ret;
|
|
}
|
|
#endif
|
|
|
|
/* sys_io_destroy:
|
|
* Destroy the aio_context specified. May cancel any outstanding
|
|
* AIOs and block on completion. Will fail with -ENOSYS if not
|
|
* implemented. May fail with -EINVAL if the context pointed to
|
|
* is invalid.
|
|
*/
|
|
SYSCALL_DEFINE1(io_destroy, aio_context_t, ctx)
|
|
{
|
|
struct kioctx *ioctx = lookup_ioctx(ctx);
|
|
if (likely(NULL != ioctx)) {
|
|
struct ctx_rq_wait wait;
|
|
int ret;
|
|
|
|
init_completion(&wait.comp);
|
|
atomic_set(&wait.count, 1);
|
|
|
|
/* Pass requests_done to kill_ioctx() where it can be set
|
|
* in a thread-safe way. If we try to set it here then we have
|
|
* a race condition if two io_destroy() called simultaneously.
|
|
*/
|
|
ret = kill_ioctx(current->mm, ioctx, &wait);
|
|
percpu_ref_put(&ioctx->users);
|
|
|
|
/* Wait until all IO for the context are done. Otherwise kernel
|
|
* keep using user-space buffers even if user thinks the context
|
|
* is destroyed.
|
|
*/
|
|
if (!ret)
|
|
wait_for_completion(&wait.comp);
|
|
|
|
return ret;
|
|
}
|
|
pr_debug("EINVAL: invalid context id\n");
|
|
return -EINVAL;
|
|
}
|
|
|
|
static int aio_setup_rw(int rw, struct iocb *iocb, struct iovec **iovec,
|
|
bool vectored, bool compat, struct iov_iter *iter)
|
|
{
|
|
void __user *buf = (void __user *)(uintptr_t)iocb->aio_buf;
|
|
size_t len = iocb->aio_nbytes;
|
|
|
|
if (!vectored) {
|
|
ssize_t ret = import_single_range(rw, buf, len, *iovec, iter);
|
|
*iovec = NULL;
|
|
return ret;
|
|
}
|
|
#ifdef CONFIG_COMPAT
|
|
if (compat)
|
|
return compat_import_iovec(rw, buf, len, UIO_FASTIOV, iovec,
|
|
iter);
|
|
#endif
|
|
return import_iovec(rw, buf, len, UIO_FASTIOV, iovec, iter);
|
|
}
|
|
|
|
static inline ssize_t aio_ret(struct kiocb *req, ssize_t ret)
|
|
{
|
|
switch (ret) {
|
|
case -EIOCBQUEUED:
|
|
return ret;
|
|
case -ERESTARTSYS:
|
|
case -ERESTARTNOINTR:
|
|
case -ERESTARTNOHAND:
|
|
case -ERESTART_RESTARTBLOCK:
|
|
/*
|
|
* There's no easy way to restart the syscall since other AIO's
|
|
* may be already running. Just fail this IO with EINTR.
|
|
*/
|
|
ret = -EINTR;
|
|
/*FALLTHRU*/
|
|
default:
|
|
aio_complete(req, ret, 0);
|
|
return 0;
|
|
}
|
|
}
|
|
|
|
static ssize_t aio_read(struct kiocb *req, struct iocb *iocb, bool vectored,
|
|
bool compat)
|
|
{
|
|
struct file *file = req->ki_filp;
|
|
struct iovec inline_vecs[UIO_FASTIOV], *iovec = inline_vecs;
|
|
struct iov_iter iter;
|
|
ssize_t ret;
|
|
|
|
if (unlikely(!(file->f_mode & FMODE_READ)))
|
|
return -EBADF;
|
|
if (unlikely(!file->f_op->read_iter))
|
|
return -EINVAL;
|
|
|
|
ret = aio_setup_rw(READ, iocb, &iovec, vectored, compat, &iter);
|
|
if (ret)
|
|
return ret;
|
|
ret = rw_verify_area(READ, file, &req->ki_pos, iov_iter_count(&iter));
|
|
if (!ret)
|
|
ret = aio_ret(req, file->f_op->read_iter(req, &iter));
|
|
kfree(iovec);
|
|
return ret;
|
|
}
|
|
|
|
static ssize_t aio_write(struct kiocb *req, struct iocb *iocb, bool vectored,
|
|
bool compat)
|
|
{
|
|
struct file *file = req->ki_filp;
|
|
struct iovec inline_vecs[UIO_FASTIOV], *iovec = inline_vecs;
|
|
struct iov_iter iter;
|
|
ssize_t ret;
|
|
|
|
if (unlikely(!(file->f_mode & FMODE_WRITE)))
|
|
return -EBADF;
|
|
if (unlikely(!file->f_op->write_iter))
|
|
return -EINVAL;
|
|
|
|
ret = aio_setup_rw(WRITE, iocb, &iovec, vectored, compat, &iter);
|
|
if (ret)
|
|
return ret;
|
|
ret = rw_verify_area(WRITE, file, &req->ki_pos, iov_iter_count(&iter));
|
|
if (!ret) {
|
|
req->ki_flags |= IOCB_WRITE;
|
|
file_start_write(file);
|
|
ret = aio_ret(req, file->f_op->write_iter(req, &iter));
|
|
/*
|
|
* We release freeze protection in aio_complete(). Fool lockdep
|
|
* by telling it the lock got released so that it doesn't
|
|
* complain about held lock when we return to userspace.
|
|
*/
|
|
if (S_ISREG(file_inode(file)->i_mode))
|
|
__sb_writers_release(file_inode(file)->i_sb, SB_FREEZE_WRITE);
|
|
}
|
|
kfree(iovec);
|
|
return ret;
|
|
}
|
|
|
|
static int io_submit_one(struct kioctx *ctx, struct iocb __user *user_iocb,
|
|
struct iocb *iocb, bool compat)
|
|
{
|
|
struct aio_kiocb *req;
|
|
struct file *file;
|
|
ssize_t ret;
|
|
|
|
/* enforce forwards compatibility on users */
|
|
if (unlikely(iocb->aio_reserved1 || iocb->aio_reserved2)) {
|
|
pr_debug("EINVAL: reserve field set\n");
|
|
return -EINVAL;
|
|
}
|
|
|
|
/* prevent overflows */
|
|
if (unlikely(
|
|
(iocb->aio_buf != (unsigned long)iocb->aio_buf) ||
|
|
(iocb->aio_nbytes != (size_t)iocb->aio_nbytes) ||
|
|
((ssize_t)iocb->aio_nbytes < 0)
|
|
)) {
|
|
pr_debug("EINVAL: overflow check\n");
|
|
return -EINVAL;
|
|
}
|
|
|
|
req = aio_get_req(ctx);
|
|
if (unlikely(!req))
|
|
return -EAGAIN;
|
|
|
|
req->common.ki_filp = file = fget(iocb->aio_fildes);
|
|
if (unlikely(!req->common.ki_filp)) {
|
|
ret = -EBADF;
|
|
goto out_put_req;
|
|
}
|
|
req->common.ki_pos = iocb->aio_offset;
|
|
req->common.ki_complete = aio_complete;
|
|
req->common.ki_flags = iocb_flags(req->common.ki_filp);
|
|
|
|
if (iocb->aio_flags & IOCB_FLAG_RESFD) {
|
|
/*
|
|
* If the IOCB_FLAG_RESFD flag of aio_flags is set, get an
|
|
* instance of the file* now. The file descriptor must be
|
|
* an eventfd() fd, and will be signaled for each completed
|
|
* event using the eventfd_signal() function.
|
|
*/
|
|
req->ki_eventfd = eventfd_ctx_fdget((int) iocb->aio_resfd);
|
|
if (IS_ERR(req->ki_eventfd)) {
|
|
ret = PTR_ERR(req->ki_eventfd);
|
|
req->ki_eventfd = NULL;
|
|
goto out_put_req;
|
|
}
|
|
|
|
req->common.ki_flags |= IOCB_EVENTFD;
|
|
}
|
|
|
|
ret = put_user(KIOCB_KEY, &user_iocb->aio_key);
|
|
if (unlikely(ret)) {
|
|
pr_debug("EFAULT: aio_key\n");
|
|
goto out_put_req;
|
|
}
|
|
|
|
req->ki_user_iocb = user_iocb;
|
|
req->ki_user_data = iocb->aio_data;
|
|
|
|
get_file(file);
|
|
switch (iocb->aio_lio_opcode) {
|
|
case IOCB_CMD_PREAD:
|
|
ret = aio_read(&req->common, iocb, false, compat);
|
|
break;
|
|
case IOCB_CMD_PWRITE:
|
|
ret = aio_write(&req->common, iocb, false, compat);
|
|
break;
|
|
case IOCB_CMD_PREADV:
|
|
ret = aio_read(&req->common, iocb, true, compat);
|
|
break;
|
|
case IOCB_CMD_PWRITEV:
|
|
ret = aio_write(&req->common, iocb, true, compat);
|
|
break;
|
|
default:
|
|
pr_debug("invalid aio operation %d\n", iocb->aio_lio_opcode);
|
|
ret = -EINVAL;
|
|
break;
|
|
}
|
|
fput(file);
|
|
|
|
if (ret && ret != -EIOCBQUEUED)
|
|
goto out_put_req;
|
|
return 0;
|
|
out_put_req:
|
|
put_reqs_available(ctx, 1);
|
|
percpu_ref_put(&ctx->reqs);
|
|
kiocb_free(req);
|
|
return ret;
|
|
}
|
|
|
|
static long do_io_submit(aio_context_t ctx_id, long nr,
|
|
struct iocb __user *__user *iocbpp, bool compat)
|
|
{
|
|
struct kioctx *ctx;
|
|
long ret = 0;
|
|
int i = 0;
|
|
struct blk_plug plug;
|
|
|
|
if (unlikely(nr < 0))
|
|
return -EINVAL;
|
|
|
|
if (unlikely(nr > LONG_MAX/sizeof(*iocbpp)))
|
|
nr = LONG_MAX/sizeof(*iocbpp);
|
|
|
|
if (unlikely(!access_ok(VERIFY_READ, iocbpp, (nr*sizeof(*iocbpp)))))
|
|
return -EFAULT;
|
|
|
|
ctx = lookup_ioctx(ctx_id);
|
|
if (unlikely(!ctx)) {
|
|
pr_debug("EINVAL: invalid context id\n");
|
|
return -EINVAL;
|
|
}
|
|
|
|
blk_start_plug(&plug);
|
|
|
|
/*
|
|
* AKPM: should this return a partial result if some of the IOs were
|
|
* successfully submitted?
|
|
*/
|
|
for (i=0; i<nr; i++) {
|
|
struct iocb __user *user_iocb;
|
|
struct iocb tmp;
|
|
|
|
if (unlikely(__get_user(user_iocb, iocbpp + i))) {
|
|
ret = -EFAULT;
|
|
break;
|
|
}
|
|
|
|
if (unlikely(copy_from_user(&tmp, user_iocb, sizeof(tmp)))) {
|
|
ret = -EFAULT;
|
|
break;
|
|
}
|
|
|
|
ret = io_submit_one(ctx, user_iocb, &tmp, compat);
|
|
if (ret)
|
|
break;
|
|
}
|
|
blk_finish_plug(&plug);
|
|
|
|
percpu_ref_put(&ctx->users);
|
|
return i ? i : ret;
|
|
}
|
|
|
|
/* sys_io_submit:
|
|
* Queue the nr iocbs pointed to by iocbpp for processing. Returns
|
|
* the number of iocbs queued. May return -EINVAL if the aio_context
|
|
* specified by ctx_id is invalid, if nr is < 0, if the iocb at
|
|
* *iocbpp[0] is not properly initialized, if the operation specified
|
|
* is invalid for the file descriptor in the iocb. May fail with
|
|
* -EFAULT if any of the data structures point to invalid data. May
|
|
* fail with -EBADF if the file descriptor specified in the first
|
|
* iocb is invalid. May fail with -EAGAIN if insufficient resources
|
|
* are available to queue any iocbs. Will return 0 if nr is 0. Will
|
|
* fail with -ENOSYS if not implemented.
|
|
*/
|
|
SYSCALL_DEFINE3(io_submit, aio_context_t, ctx_id, long, nr,
|
|
struct iocb __user * __user *, iocbpp)
|
|
{
|
|
return do_io_submit(ctx_id, nr, iocbpp, 0);
|
|
}
|
|
|
|
#ifdef CONFIG_COMPAT
|
|
static inline long
|
|
copy_iocb(long nr, u32 __user *ptr32, struct iocb __user * __user *ptr64)
|
|
{
|
|
compat_uptr_t uptr;
|
|
int i;
|
|
|
|
for (i = 0; i < nr; ++i) {
|
|
if (get_user(uptr, ptr32 + i))
|
|
return -EFAULT;
|
|
if (put_user(compat_ptr(uptr), ptr64 + i))
|
|
return -EFAULT;
|
|
}
|
|
return 0;
|
|
}
|
|
|
|
#define MAX_AIO_SUBMITS (PAGE_SIZE/sizeof(struct iocb *))
|
|
|
|
COMPAT_SYSCALL_DEFINE3(io_submit, compat_aio_context_t, ctx_id,
|
|
int, nr, u32 __user *, iocb)
|
|
{
|
|
struct iocb __user * __user *iocb64;
|
|
long ret;
|
|
|
|
if (unlikely(nr < 0))
|
|
return -EINVAL;
|
|
|
|
if (nr > MAX_AIO_SUBMITS)
|
|
nr = MAX_AIO_SUBMITS;
|
|
|
|
iocb64 = compat_alloc_user_space(nr * sizeof(*iocb64));
|
|
ret = copy_iocb(nr, iocb, iocb64);
|
|
if (!ret)
|
|
ret = do_io_submit(ctx_id, nr, iocb64, 1);
|
|
return ret;
|
|
}
|
|
#endif
|
|
|
|
/* lookup_kiocb
|
|
* Finds a given iocb for cancellation.
|
|
*/
|
|
static struct aio_kiocb *
|
|
lookup_kiocb(struct kioctx *ctx, struct iocb __user *iocb, u32 key)
|
|
{
|
|
struct aio_kiocb *kiocb;
|
|
|
|
assert_spin_locked(&ctx->ctx_lock);
|
|
|
|
if (key != KIOCB_KEY)
|
|
return NULL;
|
|
|
|
/* TODO: use a hash or array, this sucks. */
|
|
list_for_each_entry(kiocb, &ctx->active_reqs, ki_list) {
|
|
if (kiocb->ki_user_iocb == iocb)
|
|
return kiocb;
|
|
}
|
|
return NULL;
|
|
}
|
|
|
|
/* sys_io_cancel:
|
|
* Attempts to cancel an iocb previously passed to io_submit. If
|
|
* the operation is successfully cancelled, the resulting event is
|
|
* copied into the memory pointed to by result without being placed
|
|
* into the completion queue and 0 is returned. May fail with
|
|
* -EFAULT if any of the data structures pointed to are invalid.
|
|
* May fail with -EINVAL if aio_context specified by ctx_id is
|
|
* invalid. May fail with -EAGAIN if the iocb specified was not
|
|
* cancelled. Will fail with -ENOSYS if not implemented.
|
|
*/
|
|
SYSCALL_DEFINE3(io_cancel, aio_context_t, ctx_id, struct iocb __user *, iocb,
|
|
struct io_event __user *, result)
|
|
{
|
|
struct kioctx *ctx;
|
|
struct aio_kiocb *kiocb;
|
|
u32 key;
|
|
int ret;
|
|
|
|
ret = get_user(key, &iocb->aio_key);
|
|
if (unlikely(ret))
|
|
return -EFAULT;
|
|
|
|
ctx = lookup_ioctx(ctx_id);
|
|
if (unlikely(!ctx))
|
|
return -EINVAL;
|
|
|
|
spin_lock_irq(&ctx->ctx_lock);
|
|
|
|
kiocb = lookup_kiocb(ctx, iocb, key);
|
|
if (kiocb)
|
|
ret = kiocb_cancel(kiocb);
|
|
else
|
|
ret = -EINVAL;
|
|
|
|
spin_unlock_irq(&ctx->ctx_lock);
|
|
|
|
if (!ret) {
|
|
/*
|
|
* The result argument is no longer used - the io_event is
|
|
* always delivered via the ring buffer. -EINPROGRESS indicates
|
|
* cancellation is progress:
|
|
*/
|
|
ret = -EINPROGRESS;
|
|
}
|
|
|
|
percpu_ref_put(&ctx->users);
|
|
|
|
return ret;
|
|
}
|
|
|
|
/* io_getevents:
|
|
* Attempts to read at least min_nr events and up to nr events from
|
|
* the completion queue for the aio_context specified by ctx_id. If
|
|
* it succeeds, the number of read events is returned. May fail with
|
|
* -EINVAL if ctx_id is invalid, if min_nr is out of range, if nr is
|
|
* out of range, if timeout is out of range. May fail with -EFAULT
|
|
* if any of the memory specified is invalid. May return 0 or
|
|
* < min_nr if the timeout specified by timeout has elapsed
|
|
* before sufficient events are available, where timeout == NULL
|
|
* specifies an infinite timeout. Note that the timeout pointed to by
|
|
* timeout is relative. Will fail with -ENOSYS if not implemented.
|
|
*/
|
|
SYSCALL_DEFINE5(io_getevents, aio_context_t, ctx_id,
|
|
long, min_nr,
|
|
long, nr,
|
|
struct io_event __user *, events,
|
|
struct timespec __user *, timeout)
|
|
{
|
|
struct kioctx *ioctx = lookup_ioctx(ctx_id);
|
|
long ret = -EINVAL;
|
|
|
|
if (likely(ioctx)) {
|
|
if (likely(min_nr <= nr && min_nr >= 0))
|
|
ret = read_events(ioctx, min_nr, nr, events, timeout);
|
|
percpu_ref_put(&ioctx->users);
|
|
}
|
|
return ret;
|
|
}
|
|
|
|
#ifdef CONFIG_COMPAT
|
|
COMPAT_SYSCALL_DEFINE5(io_getevents, compat_aio_context_t, ctx_id,
|
|
compat_long_t, min_nr,
|
|
compat_long_t, nr,
|
|
struct io_event __user *, events,
|
|
struct compat_timespec __user *, timeout)
|
|
{
|
|
struct timespec t;
|
|
struct timespec __user *ut = NULL;
|
|
|
|
if (timeout) {
|
|
if (compat_get_timespec(&t, timeout))
|
|
return -EFAULT;
|
|
|
|
ut = compat_alloc_user_space(sizeof(*ut));
|
|
if (copy_to_user(ut, &t, sizeof(t)))
|
|
return -EFAULT;
|
|
}
|
|
return sys_io_getevents(ctx_id, min_nr, nr, events, ut);
|
|
}
|
|
#endif
|