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![Andreas Mohr](/assets/img/avatar_default.png)
acquired (aquired) contiguous (contigious) successful (succesful, succesfull) surprise (suprise) whether (weather) some other misspellings Signed-off-by: Andreas Mohr <andi@lisas.de> Signed-off-by: Adrian Bunk <bunk@stusta.de>
1721 lines
44 KiB
C
1721 lines
44 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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#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/module.h>
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#include <linux/syscalls.h>
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#define DEBUG 0
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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/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 <asm/kmap_types.h>
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#include <asm/uaccess.h>
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#include <asm/mmu_context.h>
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#if DEBUG > 1
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#define dprintk printk
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#else
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#define dprintk(x...) do { ; } while (0)
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#endif
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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 kmem_cache_t *kiocb_cachep;
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static kmem_cache_t *kioctx_cachep;
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static struct workqueue_struct *aio_wq;
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/* Used for rare fput completion. */
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static void aio_fput_routine(void *);
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static DECLARE_WORK(fput_work, aio_fput_routine, NULL);
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static DEFINE_SPINLOCK(fput_lock);
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static LIST_HEAD(fput_head);
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static void aio_kick_handler(void *);
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static void aio_queue_work(struct kioctx *);
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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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kiocb_cachep = kmem_cache_create("kiocb", sizeof(struct kiocb),
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0, SLAB_HWCACHE_ALIGN|SLAB_PANIC, NULL, NULL);
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kioctx_cachep = kmem_cache_create("kioctx", sizeof(struct kioctx),
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0, SLAB_HWCACHE_ALIGN|SLAB_PANIC, NULL, NULL);
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aio_wq = create_workqueue("aio");
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pr_debug("aio_setup: sizeof(struct page) = %d\n", (int)sizeof(struct page));
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return 0;
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}
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static void aio_free_ring(struct kioctx *ctx)
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{
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struct aio_ring_info *info = &ctx->ring_info;
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long i;
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for (i=0; i<info->nr_pages; i++)
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put_page(info->ring_pages[i]);
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if (info->mmap_size) {
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down_write(&ctx->mm->mmap_sem);
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do_munmap(ctx->mm, info->mmap_base, info->mmap_size);
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up_write(&ctx->mm->mmap_sem);
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}
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if (info->ring_pages && info->ring_pages != info->internal_pages)
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kfree(info->ring_pages);
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info->ring_pages = NULL;
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info->nr = 0;
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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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struct aio_ring_info *info = &ctx->ring_info;
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unsigned nr_events = ctx->max_reqs;
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unsigned long size;
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int nr_pages;
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/* Compensate for the ring buffer's head/tail overlap entry */
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nr_events += 2; /* 1 is required, 2 for good luck */
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size = sizeof(struct aio_ring);
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size += sizeof(struct io_event) * nr_events;
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nr_pages = (size + PAGE_SIZE-1) >> PAGE_SHIFT;
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if (nr_pages < 0)
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return -EINVAL;
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nr_events = (PAGE_SIZE * nr_pages - sizeof(struct aio_ring)) / sizeof(struct io_event);
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info->nr = 0;
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info->ring_pages = info->internal_pages;
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if (nr_pages > AIO_RING_PAGES) {
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info->ring_pages = kcalloc(nr_pages, sizeof(struct page *), GFP_KERNEL);
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if (!info->ring_pages)
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return -ENOMEM;
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}
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info->mmap_size = nr_pages * PAGE_SIZE;
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dprintk("attempting mmap of %lu bytes\n", info->mmap_size);
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down_write(&ctx->mm->mmap_sem);
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info->mmap_base = do_mmap(NULL, 0, info->mmap_size,
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PROT_READ|PROT_WRITE, MAP_ANON|MAP_PRIVATE,
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0);
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if (IS_ERR((void *)info->mmap_base)) {
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up_write(&ctx->mm->mmap_sem);
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printk("mmap err: %ld\n", -info->mmap_base);
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info->mmap_size = 0;
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aio_free_ring(ctx);
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return -EAGAIN;
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}
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dprintk("mmap address: 0x%08lx\n", info->mmap_base);
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info->nr_pages = get_user_pages(current, ctx->mm,
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info->mmap_base, nr_pages,
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1, 0, info->ring_pages, NULL);
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up_write(&ctx->mm->mmap_sem);
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if (unlikely(info->nr_pages != nr_pages)) {
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aio_free_ring(ctx);
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return -EAGAIN;
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}
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ctx->user_id = info->mmap_base;
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info->nr = nr_events; /* trusted copy */
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ring = kmap_atomic(info->ring_pages[0], KM_USER0);
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ring->nr = nr_events; /* user copy */
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ring->id = ctx->user_id;
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ring->head = ring->tail = 0;
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ring->magic = AIO_RING_MAGIC;
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ring->compat_features = AIO_RING_COMPAT_FEATURES;
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ring->incompat_features = AIO_RING_INCOMPAT_FEATURES;
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ring->header_length = sizeof(struct aio_ring);
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kunmap_atomic(ring, KM_USER0);
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return 0;
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}
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/* aio_ring_event: returns a pointer to the event at the given index from
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* kmap_atomic(, km). Release the pointer with put_aio_ring_event();
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*/
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#define AIO_EVENTS_PER_PAGE (PAGE_SIZE / sizeof(struct io_event))
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#define AIO_EVENTS_FIRST_PAGE ((PAGE_SIZE - sizeof(struct aio_ring)) / sizeof(struct io_event))
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#define AIO_EVENTS_OFFSET (AIO_EVENTS_PER_PAGE - AIO_EVENTS_FIRST_PAGE)
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#define aio_ring_event(info, nr, km) ({ \
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unsigned pos = (nr) + AIO_EVENTS_OFFSET; \
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struct io_event *__event; \
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__event = kmap_atomic( \
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(info)->ring_pages[pos / AIO_EVENTS_PER_PAGE], km); \
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__event += pos % AIO_EVENTS_PER_PAGE; \
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__event; \
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})
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#define put_aio_ring_event(event, km) do { \
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struct io_event *__event = (event); \
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(void)__event; \
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kunmap_atomic((void *)((unsigned long)__event & PAGE_MASK), km); \
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} while(0)
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/* ioctx_alloc
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* Allocates and initializes an ioctx. Returns an ERR_PTR if it failed.
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*/
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static struct kioctx *ioctx_alloc(unsigned nr_events)
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{
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struct mm_struct *mm;
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struct kioctx *ctx;
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/* Prevent overflows */
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if ((nr_events > (0x10000000U / sizeof(struct io_event))) ||
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(nr_events > (0x10000000U / sizeof(struct kiocb)))) {
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pr_debug("ENOMEM: nr_events too high\n");
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return ERR_PTR(-EINVAL);
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}
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if ((unsigned long)nr_events > aio_max_nr)
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return ERR_PTR(-EAGAIN);
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ctx = kmem_cache_alloc(kioctx_cachep, GFP_KERNEL);
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if (!ctx)
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return ERR_PTR(-ENOMEM);
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memset(ctx, 0, sizeof(*ctx));
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ctx->max_reqs = nr_events;
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mm = ctx->mm = current->mm;
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atomic_inc(&mm->mm_count);
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atomic_set(&ctx->users, 1);
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spin_lock_init(&ctx->ctx_lock);
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spin_lock_init(&ctx->ring_info.ring_lock);
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init_waitqueue_head(&ctx->wait);
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INIT_LIST_HEAD(&ctx->active_reqs);
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INIT_LIST_HEAD(&ctx->run_list);
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INIT_WORK(&ctx->wq, aio_kick_handler, ctx);
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if (aio_setup_ring(ctx) < 0)
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goto out_freectx;
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/* limit the number of system wide aios */
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spin_lock(&aio_nr_lock);
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if (aio_nr + ctx->max_reqs > aio_max_nr ||
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aio_nr + ctx->max_reqs < aio_nr)
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ctx->max_reqs = 0;
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else
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aio_nr += ctx->max_reqs;
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spin_unlock(&aio_nr_lock);
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if (ctx->max_reqs == 0)
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goto out_cleanup;
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/* now link into global list. kludge. FIXME */
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write_lock(&mm->ioctx_list_lock);
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ctx->next = mm->ioctx_list;
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mm->ioctx_list = ctx;
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write_unlock(&mm->ioctx_list_lock);
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dprintk("aio: allocated ioctx %p[%ld]: mm=%p mask=0x%x\n",
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ctx, ctx->user_id, current->mm, ctx->ring_info.nr);
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return ctx;
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out_cleanup:
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__put_ioctx(ctx);
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return ERR_PTR(-EAGAIN);
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out_freectx:
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mmdrop(mm);
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kmem_cache_free(kioctx_cachep, ctx);
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ctx = ERR_PTR(-ENOMEM);
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dprintk("aio: error allocating ioctx %p\n", ctx);
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return ctx;
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}
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/* aio_cancel_all
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* Cancels all outstanding aio requests on an aio context. Used
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* when the processes owning a context have all exited to encourage
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* the rapid destruction of the kioctx.
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*/
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static void aio_cancel_all(struct kioctx *ctx)
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{
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int (*cancel)(struct kiocb *, struct io_event *);
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struct io_event res;
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spin_lock_irq(&ctx->ctx_lock);
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ctx->dead = 1;
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while (!list_empty(&ctx->active_reqs)) {
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struct list_head *pos = ctx->active_reqs.next;
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struct kiocb *iocb = list_kiocb(pos);
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list_del_init(&iocb->ki_list);
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cancel = iocb->ki_cancel;
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kiocbSetCancelled(iocb);
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if (cancel) {
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iocb->ki_users++;
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spin_unlock_irq(&ctx->ctx_lock);
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cancel(iocb, &res);
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spin_lock_irq(&ctx->ctx_lock);
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}
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}
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spin_unlock_irq(&ctx->ctx_lock);
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}
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static void wait_for_all_aios(struct kioctx *ctx)
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{
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struct task_struct *tsk = current;
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DECLARE_WAITQUEUE(wait, tsk);
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if (!ctx->reqs_active)
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return;
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add_wait_queue(&ctx->wait, &wait);
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set_task_state(tsk, TASK_UNINTERRUPTIBLE);
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while (ctx->reqs_active) {
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schedule();
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set_task_state(tsk, TASK_UNINTERRUPTIBLE);
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}
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__set_task_state(tsk, TASK_RUNNING);
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remove_wait_queue(&ctx->wait, &wait);
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}
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/* wait_on_sync_kiocb:
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* Waits on the given sync kiocb to complete.
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*/
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ssize_t fastcall wait_on_sync_kiocb(struct kiocb *iocb)
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{
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while (iocb->ki_users) {
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set_current_state(TASK_UNINTERRUPTIBLE);
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if (!iocb->ki_users)
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break;
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schedule();
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}
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__set_current_state(TASK_RUNNING);
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return iocb->ki_user_data;
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}
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/* exit_aio: called when the last user of mm goes away. At this point,
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* there is no way for any new requests to be submited or any of the
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* io_* syscalls to be called on the context. However, there may be
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* outstanding requests which hold references to the context; as they
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* go away, they will call put_ioctx and release any pinned memory
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* associated with the request (held via struct page * references).
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*/
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void fastcall exit_aio(struct mm_struct *mm)
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{
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struct kioctx *ctx = mm->ioctx_list;
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mm->ioctx_list = NULL;
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while (ctx) {
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struct kioctx *next = ctx->next;
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ctx->next = NULL;
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aio_cancel_all(ctx);
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wait_for_all_aios(ctx);
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/*
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* this is an overkill, but ensures we don't leave
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* the ctx on the aio_wq
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*/
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flush_workqueue(aio_wq);
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if (1 != atomic_read(&ctx->users))
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printk(KERN_DEBUG
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"exit_aio:ioctx still alive: %d %d %d\n",
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atomic_read(&ctx->users), ctx->dead,
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ctx->reqs_active);
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put_ioctx(ctx);
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ctx = next;
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}
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}
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/* __put_ioctx
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* Called when the last user of an aio context has gone away,
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* and the struct needs to be freed.
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*/
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void fastcall __put_ioctx(struct kioctx *ctx)
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{
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unsigned nr_events = ctx->max_reqs;
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if (unlikely(ctx->reqs_active))
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BUG();
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cancel_delayed_work(&ctx->wq);
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flush_workqueue(aio_wq);
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aio_free_ring(ctx);
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mmdrop(ctx->mm);
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ctx->mm = NULL;
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pr_debug("__put_ioctx: freeing %p\n", ctx);
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kmem_cache_free(kioctx_cachep, ctx);
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if (nr_events) {
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spin_lock(&aio_nr_lock);
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BUG_ON(aio_nr - nr_events > aio_nr);
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aio_nr -= nr_events;
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spin_unlock(&aio_nr_lock);
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}
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}
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/* aio_get_req
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* Allocate a slot for an aio request. Increments the users count
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* of the kioctx so that the kioctx stays around until all requests are
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* complete. Returns NULL if no requests are free.
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*
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* Returns with kiocb->users set to 2. The io submit code path holds
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* an extra reference while submitting the i/o.
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* This prevents races between the aio code path referencing the
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* req (after submitting it) and aio_complete() freeing the req.
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*/
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static struct kiocb *FASTCALL(__aio_get_req(struct kioctx *ctx));
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static struct kiocb fastcall *__aio_get_req(struct kioctx *ctx)
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{
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struct kiocb *req = NULL;
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struct aio_ring *ring;
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int okay = 0;
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req = kmem_cache_alloc(kiocb_cachep, GFP_KERNEL);
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if (unlikely(!req))
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return NULL;
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req->ki_flags = 0;
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req->ki_users = 2;
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req->ki_key = 0;
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req->ki_ctx = ctx;
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req->ki_cancel = NULL;
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req->ki_retry = NULL;
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req->ki_dtor = NULL;
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req->private = NULL;
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INIT_LIST_HEAD(&req->ki_run_list);
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|
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/* Check if the completion queue has enough free space to
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* accept an event from this io.
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*/
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spin_lock_irq(&ctx->ctx_lock);
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ring = kmap_atomic(ctx->ring_info.ring_pages[0], KM_USER0);
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if (ctx->reqs_active < aio_ring_avail(&ctx->ring_info, ring)) {
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list_add(&req->ki_list, &ctx->active_reqs);
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get_ioctx(ctx);
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ctx->reqs_active++;
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okay = 1;
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}
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kunmap_atomic(ring, KM_USER0);
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spin_unlock_irq(&ctx->ctx_lock);
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|
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if (!okay) {
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kmem_cache_free(kiocb_cachep, req);
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req = NULL;
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}
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return req;
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}
|
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|
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static inline struct kiocb *aio_get_req(struct kioctx *ctx)
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{
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struct kiocb *req;
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/* Handle a potential starvation case -- should be exceedingly rare as
|
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* requests will be stuck on fput_head only if the aio_fput_routine is
|
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* delayed and the requests were the last user of the struct file.
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*/
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req = __aio_get_req(ctx);
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if (unlikely(NULL == req)) {
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aio_fput_routine(NULL);
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req = __aio_get_req(ctx);
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}
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return req;
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}
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|
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static inline void really_put_req(struct kioctx *ctx, struct kiocb *req)
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{
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assert_spin_locked(&ctx->ctx_lock);
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if (req->ki_dtor)
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req->ki_dtor(req);
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kmem_cache_free(kiocb_cachep, req);
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ctx->reqs_active--;
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|
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if (unlikely(!ctx->reqs_active && ctx->dead))
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wake_up(&ctx->wait);
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}
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|
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static void aio_fput_routine(void *data)
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{
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spin_lock_irq(&fput_lock);
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while (likely(!list_empty(&fput_head))) {
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struct kiocb *req = list_kiocb(fput_head.next);
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struct kioctx *ctx = req->ki_ctx;
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|
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list_del(&req->ki_list);
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spin_unlock_irq(&fput_lock);
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|
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/* Complete the fput */
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__fput(req->ki_filp);
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|
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/* Link the iocb into the context's free list */
|
|
spin_lock_irq(&ctx->ctx_lock);
|
|
really_put_req(ctx, req);
|
|
spin_unlock_irq(&ctx->ctx_lock);
|
|
|
|
put_ioctx(ctx);
|
|
spin_lock_irq(&fput_lock);
|
|
}
|
|
spin_unlock_irq(&fput_lock);
|
|
}
|
|
|
|
/* __aio_put_req
|
|
* Returns true if this put was the last user of the request.
|
|
*/
|
|
static int __aio_put_req(struct kioctx *ctx, struct kiocb *req)
|
|
{
|
|
dprintk(KERN_DEBUG "aio_put(%p): f_count=%d\n",
|
|
req, atomic_read(&req->ki_filp->f_count));
|
|
|
|
assert_spin_locked(&ctx->ctx_lock);
|
|
|
|
req->ki_users --;
|
|
if (unlikely(req->ki_users < 0))
|
|
BUG();
|
|
if (likely(req->ki_users))
|
|
return 0;
|
|
list_del(&req->ki_list); /* remove from active_reqs */
|
|
req->ki_cancel = NULL;
|
|
req->ki_retry = NULL;
|
|
|
|
/* Must be done under the lock to serialise against cancellation.
|
|
* Call this aio_fput as it duplicates fput via the fput_work.
|
|
*/
|
|
if (unlikely(atomic_dec_and_test(&req->ki_filp->f_count))) {
|
|
get_ioctx(ctx);
|
|
spin_lock(&fput_lock);
|
|
list_add(&req->ki_list, &fput_head);
|
|
spin_unlock(&fput_lock);
|
|
queue_work(aio_wq, &fput_work);
|
|
} else
|
|
really_put_req(ctx, req);
|
|
return 1;
|
|
}
|
|
|
|
/* aio_put_req
|
|
* Returns true if this put was the last user of the kiocb,
|
|
* false if the request is still in use.
|
|
*/
|
|
int fastcall aio_put_req(struct kiocb *req)
|
|
{
|
|
struct kioctx *ctx = req->ki_ctx;
|
|
int ret;
|
|
spin_lock_irq(&ctx->ctx_lock);
|
|
ret = __aio_put_req(ctx, req);
|
|
spin_unlock_irq(&ctx->ctx_lock);
|
|
if (ret)
|
|
put_ioctx(ctx);
|
|
return ret;
|
|
}
|
|
|
|
/* Lookup an ioctx id. ioctx_list is lockless for reads.
|
|
* FIXME: this is O(n) and is only suitable for development.
|
|
*/
|
|
struct kioctx *lookup_ioctx(unsigned long ctx_id)
|
|
{
|
|
struct kioctx *ioctx;
|
|
struct mm_struct *mm;
|
|
|
|
mm = current->mm;
|
|
read_lock(&mm->ioctx_list_lock);
|
|
for (ioctx = mm->ioctx_list; ioctx; ioctx = ioctx->next)
|
|
if (likely(ioctx->user_id == ctx_id && !ioctx->dead)) {
|
|
get_ioctx(ioctx);
|
|
break;
|
|
}
|
|
read_unlock(&mm->ioctx_list_lock);
|
|
|
|
return ioctx;
|
|
}
|
|
|
|
/*
|
|
* use_mm
|
|
* Makes the calling kernel thread take on the specified
|
|
* mm context.
|
|
* Called by the retry thread execute retries within the
|
|
* iocb issuer's mm context, so that copy_from/to_user
|
|
* operations work seamlessly for aio.
|
|
* (Note: this routine is intended to be called only
|
|
* from a kernel thread context)
|
|
*/
|
|
static void use_mm(struct mm_struct *mm)
|
|
{
|
|
struct mm_struct *active_mm;
|
|
struct task_struct *tsk = current;
|
|
|
|
task_lock(tsk);
|
|
tsk->flags |= PF_BORROWED_MM;
|
|
active_mm = tsk->active_mm;
|
|
atomic_inc(&mm->mm_count);
|
|
tsk->mm = mm;
|
|
tsk->active_mm = mm;
|
|
/*
|
|
* Note that on UML this *requires* PF_BORROWED_MM to be set, otherwise
|
|
* it won't work. Update it accordingly if you change it here
|
|
*/
|
|
activate_mm(active_mm, mm);
|
|
task_unlock(tsk);
|
|
|
|
mmdrop(active_mm);
|
|
}
|
|
|
|
/*
|
|
* unuse_mm
|
|
* Reverses the effect of use_mm, i.e. releases the
|
|
* specified mm context which was earlier taken on
|
|
* by the calling kernel thread
|
|
* (Note: this routine is intended to be called only
|
|
* from a kernel thread context)
|
|
*
|
|
* Comments: Called with ctx->ctx_lock held. This nests
|
|
* task_lock instead ctx_lock.
|
|
*/
|
|
static void unuse_mm(struct mm_struct *mm)
|
|
{
|
|
struct task_struct *tsk = current;
|
|
|
|
task_lock(tsk);
|
|
tsk->flags &= ~PF_BORROWED_MM;
|
|
tsk->mm = NULL;
|
|
/* active_mm is still 'mm' */
|
|
enter_lazy_tlb(mm, tsk);
|
|
task_unlock(tsk);
|
|
}
|
|
|
|
/*
|
|
* Queue up a kiocb to be retried. Assumes that the kiocb
|
|
* has already been marked as kicked, and places it on
|
|
* the retry run list for the corresponding ioctx, if it
|
|
* isn't already queued. Returns 1 if it actually queued
|
|
* the kiocb (to tell the caller to activate the work
|
|
* queue to process it), or 0, if it found that it was
|
|
* already queued.
|
|
*/
|
|
static inline int __queue_kicked_iocb(struct kiocb *iocb)
|
|
{
|
|
struct kioctx *ctx = iocb->ki_ctx;
|
|
|
|
assert_spin_locked(&ctx->ctx_lock);
|
|
|
|
if (list_empty(&iocb->ki_run_list)) {
|
|
list_add_tail(&iocb->ki_run_list,
|
|
&ctx->run_list);
|
|
return 1;
|
|
}
|
|
return 0;
|
|
}
|
|
|
|
/* aio_run_iocb
|
|
* This is the core aio execution routine. It is
|
|
* invoked both for initial i/o submission and
|
|
* subsequent retries via the aio_kick_handler.
|
|
* Expects to be invoked with iocb->ki_ctx->lock
|
|
* already held. The lock is released and reacquired
|
|
* as needed during processing.
|
|
*
|
|
* Calls the iocb retry method (already setup for the
|
|
* iocb on initial submission) for operation specific
|
|
* handling, but takes care of most of common retry
|
|
* execution details for a given iocb. The retry method
|
|
* needs to be non-blocking as far as possible, to avoid
|
|
* holding up other iocbs waiting to be serviced by the
|
|
* retry kernel thread.
|
|
*
|
|
* The trickier parts in this code have to do with
|
|
* ensuring that only one retry instance is in progress
|
|
* for a given iocb at any time. Providing that guarantee
|
|
* simplifies the coding of individual aio operations as
|
|
* it avoids various potential races.
|
|
*/
|
|
static ssize_t aio_run_iocb(struct kiocb *iocb)
|
|
{
|
|
struct kioctx *ctx = iocb->ki_ctx;
|
|
ssize_t (*retry)(struct kiocb *);
|
|
ssize_t ret;
|
|
|
|
if (iocb->ki_retried++ > 1024*1024) {
|
|
printk("Maximal retry count. Bytes done %Zd\n",
|
|
iocb->ki_nbytes - iocb->ki_left);
|
|
return -EAGAIN;
|
|
}
|
|
|
|
if (!(iocb->ki_retried & 0xff)) {
|
|
pr_debug("%ld retry: %d of %d\n", iocb->ki_retried,
|
|
iocb->ki_nbytes - iocb->ki_left, iocb->ki_nbytes);
|
|
}
|
|
|
|
if (!(retry = iocb->ki_retry)) {
|
|
printk("aio_run_iocb: iocb->ki_retry = NULL\n");
|
|
return 0;
|
|
}
|
|
|
|
/*
|
|
* We don't want the next retry iteration for this
|
|
* operation to start until this one has returned and
|
|
* updated the iocb state. However, wait_queue functions
|
|
* can trigger a kick_iocb from interrupt context in the
|
|
* meantime, indicating that data is available for the next
|
|
* iteration. We want to remember that and enable the
|
|
* next retry iteration _after_ we are through with
|
|
* this one.
|
|
*
|
|
* So, in order to be able to register a "kick", but
|
|
* prevent it from being queued now, we clear the kick
|
|
* flag, but make the kick code *think* that the iocb is
|
|
* still on the run list until we are actually done.
|
|
* When we are done with this iteration, we check if
|
|
* the iocb was kicked in the meantime and if so, queue
|
|
* it up afresh.
|
|
*/
|
|
|
|
kiocbClearKicked(iocb);
|
|
|
|
/*
|
|
* This is so that aio_complete knows it doesn't need to
|
|
* pull the iocb off the run list (We can't just call
|
|
* INIT_LIST_HEAD because we don't want a kick_iocb to
|
|
* queue this on the run list yet)
|
|
*/
|
|
iocb->ki_run_list.next = iocb->ki_run_list.prev = NULL;
|
|
spin_unlock_irq(&ctx->ctx_lock);
|
|
|
|
/* Quit retrying if the i/o has been cancelled */
|
|
if (kiocbIsCancelled(iocb)) {
|
|
ret = -EINTR;
|
|
aio_complete(iocb, ret, 0);
|
|
/* must not access the iocb after this */
|
|
goto out;
|
|
}
|
|
|
|
/*
|
|
* Now we are all set to call the retry method in async
|
|
* context. By setting this thread's io_wait context
|
|
* to point to the wait queue entry inside the currently
|
|
* running iocb for the duration of the retry, we ensure
|
|
* that async notification wakeups are queued by the
|
|
* operation instead of blocking waits, and when notified,
|
|
* cause the iocb to be kicked for continuation (through
|
|
* the aio_wake_function callback).
|
|
*/
|
|
BUG_ON(current->io_wait != NULL);
|
|
current->io_wait = &iocb->ki_wait;
|
|
ret = retry(iocb);
|
|
current->io_wait = NULL;
|
|
|
|
if (ret != -EIOCBRETRY && ret != -EIOCBQUEUED) {
|
|
BUG_ON(!list_empty(&iocb->ki_wait.task_list));
|
|
aio_complete(iocb, ret, 0);
|
|
}
|
|
out:
|
|
spin_lock_irq(&ctx->ctx_lock);
|
|
|
|
if (-EIOCBRETRY == ret) {
|
|
/*
|
|
* OK, now that we are done with this iteration
|
|
* and know that there is more left to go,
|
|
* this is where we let go so that a subsequent
|
|
* "kick" can start the next iteration
|
|
*/
|
|
|
|
/* will make __queue_kicked_iocb succeed from here on */
|
|
INIT_LIST_HEAD(&iocb->ki_run_list);
|
|
/* we must queue the next iteration ourselves, if it
|
|
* has already been kicked */
|
|
if (kiocbIsKicked(iocb)) {
|
|
__queue_kicked_iocb(iocb);
|
|
|
|
/*
|
|
* __queue_kicked_iocb will always return 1 here, because
|
|
* iocb->ki_run_list is empty at this point so it should
|
|
* be safe to unconditionally queue the context into the
|
|
* work queue.
|
|
*/
|
|
aio_queue_work(ctx);
|
|
}
|
|
}
|
|
return ret;
|
|
}
|
|
|
|
/*
|
|
* __aio_run_iocbs:
|
|
* Process all pending retries queued on the ioctx
|
|
* run list.
|
|
* Assumes it is operating within the aio issuer's mm
|
|
* context.
|
|
*/
|
|
static int __aio_run_iocbs(struct kioctx *ctx)
|
|
{
|
|
struct kiocb *iocb;
|
|
struct list_head run_list;
|
|
|
|
assert_spin_locked(&ctx->ctx_lock);
|
|
|
|
list_replace_init(&ctx->run_list, &run_list);
|
|
while (!list_empty(&run_list)) {
|
|
iocb = list_entry(run_list.next, struct kiocb,
|
|
ki_run_list);
|
|
list_del(&iocb->ki_run_list);
|
|
/*
|
|
* Hold an extra reference while retrying i/o.
|
|
*/
|
|
iocb->ki_users++; /* grab extra reference */
|
|
aio_run_iocb(iocb);
|
|
if (__aio_put_req(ctx, iocb)) /* drop extra ref */
|
|
put_ioctx(ctx);
|
|
}
|
|
if (!list_empty(&ctx->run_list))
|
|
return 1;
|
|
return 0;
|
|
}
|
|
|
|
static void aio_queue_work(struct kioctx * ctx)
|
|
{
|
|
unsigned long timeout;
|
|
/*
|
|
* if someone is waiting, get the work started right
|
|
* away, otherwise, use a longer delay
|
|
*/
|
|
smp_mb();
|
|
if (waitqueue_active(&ctx->wait))
|
|
timeout = 1;
|
|
else
|
|
timeout = HZ/10;
|
|
queue_delayed_work(aio_wq, &ctx->wq, timeout);
|
|
}
|
|
|
|
|
|
/*
|
|
* aio_run_iocbs:
|
|
* Process all pending retries queued on the ioctx
|
|
* run list.
|
|
* Assumes it is operating within the aio issuer's mm
|
|
* context.
|
|
*/
|
|
static inline void aio_run_iocbs(struct kioctx *ctx)
|
|
{
|
|
int requeue;
|
|
|
|
spin_lock_irq(&ctx->ctx_lock);
|
|
|
|
requeue = __aio_run_iocbs(ctx);
|
|
spin_unlock_irq(&ctx->ctx_lock);
|
|
if (requeue)
|
|
aio_queue_work(ctx);
|
|
}
|
|
|
|
/*
|
|
* just like aio_run_iocbs, but keeps running them until
|
|
* the list stays empty
|
|
*/
|
|
static inline void aio_run_all_iocbs(struct kioctx *ctx)
|
|
{
|
|
spin_lock_irq(&ctx->ctx_lock);
|
|
while (__aio_run_iocbs(ctx))
|
|
;
|
|
spin_unlock_irq(&ctx->ctx_lock);
|
|
}
|
|
|
|
/*
|
|
* aio_kick_handler:
|
|
* Work queue handler triggered to process pending
|
|
* retries on an ioctx. Takes on the aio issuer's
|
|
* mm context before running the iocbs, so that
|
|
* copy_xxx_user operates on the issuer's address
|
|
* space.
|
|
* Run on aiod's context.
|
|
*/
|
|
static void aio_kick_handler(void *data)
|
|
{
|
|
struct kioctx *ctx = data;
|
|
mm_segment_t oldfs = get_fs();
|
|
int requeue;
|
|
|
|
set_fs(USER_DS);
|
|
use_mm(ctx->mm);
|
|
spin_lock_irq(&ctx->ctx_lock);
|
|
requeue =__aio_run_iocbs(ctx);
|
|
unuse_mm(ctx->mm);
|
|
spin_unlock_irq(&ctx->ctx_lock);
|
|
set_fs(oldfs);
|
|
/*
|
|
* we're in a worker thread already, don't use queue_delayed_work,
|
|
*/
|
|
if (requeue)
|
|
queue_work(aio_wq, &ctx->wq);
|
|
}
|
|
|
|
|
|
/*
|
|
* Called by kick_iocb to queue the kiocb for retry
|
|
* and if required activate the aio work queue to process
|
|
* it
|
|
*/
|
|
static void try_queue_kicked_iocb(struct kiocb *iocb)
|
|
{
|
|
struct kioctx *ctx = iocb->ki_ctx;
|
|
unsigned long flags;
|
|
int run = 0;
|
|
|
|
/* We're supposed to be the only path putting the iocb back on the run
|
|
* list. If we find that the iocb is *back* on a wait queue already
|
|
* than retry has happened before we could queue the iocb. This also
|
|
* means that the retry could have completed and freed our iocb, no
|
|
* good. */
|
|
BUG_ON((!list_empty(&iocb->ki_wait.task_list)));
|
|
|
|
spin_lock_irqsave(&ctx->ctx_lock, flags);
|
|
/* set this inside the lock so that we can't race with aio_run_iocb()
|
|
* testing it and putting the iocb on the run list under the lock */
|
|
if (!kiocbTryKick(iocb))
|
|
run = __queue_kicked_iocb(iocb);
|
|
spin_unlock_irqrestore(&ctx->ctx_lock, flags);
|
|
if (run)
|
|
aio_queue_work(ctx);
|
|
}
|
|
|
|
/*
|
|
* kick_iocb:
|
|
* Called typically from a wait queue callback context
|
|
* (aio_wake_function) to trigger a retry of the iocb.
|
|
* The retry is usually executed by aio workqueue
|
|
* threads (See aio_kick_handler).
|
|
*/
|
|
void fastcall kick_iocb(struct kiocb *iocb)
|
|
{
|
|
/* sync iocbs are easy: they can only ever be executing from a
|
|
* single context. */
|
|
if (is_sync_kiocb(iocb)) {
|
|
kiocbSetKicked(iocb);
|
|
wake_up_process(iocb->ki_obj.tsk);
|
|
return;
|
|
}
|
|
|
|
try_queue_kicked_iocb(iocb);
|
|
}
|
|
EXPORT_SYMBOL(kick_iocb);
|
|
|
|
/* aio_complete
|
|
* Called when the io request on the given iocb is complete.
|
|
* Returns true if this is the last user of the request. The
|
|
* only other user of the request can be the cancellation code.
|
|
*/
|
|
int fastcall aio_complete(struct kiocb *iocb, long res, long res2)
|
|
{
|
|
struct kioctx *ctx = iocb->ki_ctx;
|
|
struct aio_ring_info *info;
|
|
struct aio_ring *ring;
|
|
struct io_event *event;
|
|
unsigned long flags;
|
|
unsigned long tail;
|
|
int ret;
|
|
|
|
/*
|
|
* 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
|
|
*/
|
|
if (is_sync_kiocb(iocb)) {
|
|
BUG_ON(iocb->ki_users != 1);
|
|
iocb->ki_user_data = res;
|
|
iocb->ki_users = 0;
|
|
wake_up_process(iocb->ki_obj.tsk);
|
|
return 1;
|
|
}
|
|
|
|
info = &ctx->ring_info;
|
|
|
|
/* add a completion event to the ring buffer.
|
|
* must be done holding ctx->ctx_lock to prevent
|
|
* other code from messing with the tail
|
|
* pointer since we might be called from irq
|
|
* context.
|
|
*/
|
|
spin_lock_irqsave(&ctx->ctx_lock, flags);
|
|
|
|
if (iocb->ki_run_list.prev && !list_empty(&iocb->ki_run_list))
|
|
list_del_init(&iocb->ki_run_list);
|
|
|
|
/*
|
|
* cancelled requests don't get events, userland was given one
|
|
* when the event got cancelled.
|
|
*/
|
|
if (kiocbIsCancelled(iocb))
|
|
goto put_rq;
|
|
|
|
ring = kmap_atomic(info->ring_pages[0], KM_IRQ1);
|
|
|
|
tail = info->tail;
|
|
event = aio_ring_event(info, tail, KM_IRQ0);
|
|
if (++tail >= info->nr)
|
|
tail = 0;
|
|
|
|
event->obj = (u64)(unsigned long)iocb->ki_obj.user;
|
|
event->data = iocb->ki_user_data;
|
|
event->res = res;
|
|
event->res2 = res2;
|
|
|
|
dprintk("aio_complete: %p[%lu]: %p: %p %Lx %lx %lx\n",
|
|
ctx, tail, iocb, iocb->ki_obj.user, 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 */
|
|
|
|
info->tail = tail;
|
|
ring->tail = tail;
|
|
|
|
put_aio_ring_event(event, KM_IRQ0);
|
|
kunmap_atomic(ring, KM_IRQ1);
|
|
|
|
pr_debug("added to ring %p at [%lu]\n", iocb, tail);
|
|
|
|
pr_debug("%ld retries: %d of %d\n", iocb->ki_retried,
|
|
iocb->ki_nbytes - iocb->ki_left, iocb->ki_nbytes);
|
|
put_rq:
|
|
/* everything turned out well, dispose of the aiocb. */
|
|
ret = __aio_put_req(ctx, iocb);
|
|
|
|
spin_unlock_irqrestore(&ctx->ctx_lock, flags);
|
|
|
|
if (waitqueue_active(&ctx->wait))
|
|
wake_up(&ctx->wait);
|
|
|
|
if (ret)
|
|
put_ioctx(ctx);
|
|
|
|
return ret;
|
|
}
|
|
|
|
/* aio_read_evt
|
|
* Pull an event off of the ioctx's event ring. Returns the number of
|
|
* events fetched (0 or 1 ;-)
|
|
* FIXME: make this use cmpxchg.
|
|
* TODO: make the ringbuffer user mmap()able (requires FIXME).
|
|
*/
|
|
static int aio_read_evt(struct kioctx *ioctx, struct io_event *ent)
|
|
{
|
|
struct aio_ring_info *info = &ioctx->ring_info;
|
|
struct aio_ring *ring;
|
|
unsigned long head;
|
|
int ret = 0;
|
|
|
|
ring = kmap_atomic(info->ring_pages[0], KM_USER0);
|
|
dprintk("in aio_read_evt h%lu t%lu m%lu\n",
|
|
(unsigned long)ring->head, (unsigned long)ring->tail,
|
|
(unsigned long)ring->nr);
|
|
|
|
if (ring->head == ring->tail)
|
|
goto out;
|
|
|
|
spin_lock(&info->ring_lock);
|
|
|
|
head = ring->head % info->nr;
|
|
if (head != ring->tail) {
|
|
struct io_event *evp = aio_ring_event(info, head, KM_USER1);
|
|
*ent = *evp;
|
|
head = (head + 1) % info->nr;
|
|
smp_mb(); /* finish reading the event before updatng the head */
|
|
ring->head = head;
|
|
ret = 1;
|
|
put_aio_ring_event(evp, KM_USER1);
|
|
}
|
|
spin_unlock(&info->ring_lock);
|
|
|
|
out:
|
|
kunmap_atomic(ring, KM_USER0);
|
|
dprintk("leaving aio_read_evt: %d h%lu t%lu\n", ret,
|
|
(unsigned long)ring->head, (unsigned long)ring->tail);
|
|
return ret;
|
|
}
|
|
|
|
struct aio_timeout {
|
|
struct timer_list timer;
|
|
int timed_out;
|
|
struct task_struct *p;
|
|
};
|
|
|
|
static void timeout_func(unsigned long data)
|
|
{
|
|
struct aio_timeout *to = (struct aio_timeout *)data;
|
|
|
|
to->timed_out = 1;
|
|
wake_up_process(to->p);
|
|
}
|
|
|
|
static inline void init_timeout(struct aio_timeout *to)
|
|
{
|
|
init_timer(&to->timer);
|
|
to->timer.data = (unsigned long)to;
|
|
to->timer.function = timeout_func;
|
|
to->timed_out = 0;
|
|
to->p = current;
|
|
}
|
|
|
|
static inline void set_timeout(long start_jiffies, struct aio_timeout *to,
|
|
const struct timespec *ts)
|
|
{
|
|
to->timer.expires = start_jiffies + timespec_to_jiffies(ts);
|
|
if (time_after(to->timer.expires, jiffies))
|
|
add_timer(&to->timer);
|
|
else
|
|
to->timed_out = 1;
|
|
}
|
|
|
|
static inline void clear_timeout(struct aio_timeout *to)
|
|
{
|
|
del_singleshot_timer_sync(&to->timer);
|
|
}
|
|
|
|
static int read_events(struct kioctx *ctx,
|
|
long min_nr, long nr,
|
|
struct io_event __user *event,
|
|
struct timespec __user *timeout)
|
|
{
|
|
long start_jiffies = jiffies;
|
|
struct task_struct *tsk = current;
|
|
DECLARE_WAITQUEUE(wait, tsk);
|
|
int ret;
|
|
int i = 0;
|
|
struct io_event ent;
|
|
struct aio_timeout to;
|
|
int retry = 0;
|
|
|
|
/* needed to zero any padding within an entry (there shouldn't be
|
|
* any, but C is fun!
|
|
*/
|
|
memset(&ent, 0, sizeof(ent));
|
|
retry:
|
|
ret = 0;
|
|
while (likely(i < nr)) {
|
|
ret = aio_read_evt(ctx, &ent);
|
|
if (unlikely(ret <= 0))
|
|
break;
|
|
|
|
dprintk("read event: %Lx %Lx %Lx %Lx\n",
|
|
ent.data, ent.obj, ent.res, ent.res2);
|
|
|
|
/* Could we split the check in two? */
|
|
ret = -EFAULT;
|
|
if (unlikely(copy_to_user(event, &ent, sizeof(ent)))) {
|
|
dprintk("aio: lost an event due to EFAULT.\n");
|
|
break;
|
|
}
|
|
ret = 0;
|
|
|
|
/* Good, event copied to userland, update counts. */
|
|
event ++;
|
|
i ++;
|
|
}
|
|
|
|
if (min_nr <= i)
|
|
return i;
|
|
if (ret)
|
|
return ret;
|
|
|
|
/* End fast path */
|
|
|
|
/* racey check, but it gets redone */
|
|
if (!retry && unlikely(!list_empty(&ctx->run_list))) {
|
|
retry = 1;
|
|
aio_run_all_iocbs(ctx);
|
|
goto retry;
|
|
}
|
|
|
|
init_timeout(&to);
|
|
if (timeout) {
|
|
struct timespec ts;
|
|
ret = -EFAULT;
|
|
if (unlikely(copy_from_user(&ts, timeout, sizeof(ts))))
|
|
goto out;
|
|
|
|
set_timeout(start_jiffies, &to, &ts);
|
|
}
|
|
|
|
while (likely(i < nr)) {
|
|
add_wait_queue_exclusive(&ctx->wait, &wait);
|
|
do {
|
|
set_task_state(tsk, TASK_INTERRUPTIBLE);
|
|
ret = aio_read_evt(ctx, &ent);
|
|
if (ret)
|
|
break;
|
|
if (min_nr <= i)
|
|
break;
|
|
ret = 0;
|
|
if (to.timed_out) /* Only check after read evt */
|
|
break;
|
|
schedule();
|
|
if (signal_pending(tsk)) {
|
|
ret = -EINTR;
|
|
break;
|
|
}
|
|
/*ret = aio_read_evt(ctx, &ent);*/
|
|
} while (1) ;
|
|
|
|
set_task_state(tsk, TASK_RUNNING);
|
|
remove_wait_queue(&ctx->wait, &wait);
|
|
|
|
if (unlikely(ret <= 0))
|
|
break;
|
|
|
|
ret = -EFAULT;
|
|
if (unlikely(copy_to_user(event, &ent, sizeof(ent)))) {
|
|
dprintk("aio: lost an event due to EFAULT.\n");
|
|
break;
|
|
}
|
|
|
|
/* Good, event copied to userland, update counts. */
|
|
event ++;
|
|
i ++;
|
|
}
|
|
|
|
if (timeout)
|
|
clear_timeout(&to);
|
|
out:
|
|
return i ? i : ret;
|
|
}
|
|
|
|
/* Take an ioctx and remove it from the list of ioctx's. Protects
|
|
* against races with itself via ->dead.
|
|
*/
|
|
static void io_destroy(struct kioctx *ioctx)
|
|
{
|
|
struct mm_struct *mm = current->mm;
|
|
struct kioctx **tmp;
|
|
int was_dead;
|
|
|
|
/* delete the entry from the list is someone else hasn't already */
|
|
write_lock(&mm->ioctx_list_lock);
|
|
was_dead = ioctx->dead;
|
|
ioctx->dead = 1;
|
|
for (tmp = &mm->ioctx_list; *tmp && *tmp != ioctx;
|
|
tmp = &(*tmp)->next)
|
|
;
|
|
if (*tmp)
|
|
*tmp = ioctx->next;
|
|
write_unlock(&mm->ioctx_list_lock);
|
|
|
|
dprintk("aio_release(%p)\n", ioctx);
|
|
if (likely(!was_dead))
|
|
put_ioctx(ioctx); /* twice for the list */
|
|
|
|
aio_cancel_all(ioctx);
|
|
wait_for_all_aios(ioctx);
|
|
put_ioctx(ioctx); /* once for the lookup */
|
|
}
|
|
|
|
/* 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.
|
|
*/
|
|
asmlinkage long sys_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: io_setup: 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)
|
|
return 0;
|
|
|
|
get_ioctx(ioctx); /* io_destroy() expects us to hold a ref */
|
|
io_destroy(ioctx);
|
|
}
|
|
|
|
out:
|
|
return ret;
|
|
}
|
|
|
|
/* 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 -EFAULT if the context pointed to
|
|
* is invalid.
|
|
*/
|
|
asmlinkage long sys_io_destroy(aio_context_t ctx)
|
|
{
|
|
struct kioctx *ioctx = lookup_ioctx(ctx);
|
|
if (likely(NULL != ioctx)) {
|
|
io_destroy(ioctx);
|
|
return 0;
|
|
}
|
|
pr_debug("EINVAL: io_destroy: invalid context id\n");
|
|
return -EINVAL;
|
|
}
|
|
|
|
/*
|
|
* aio_p{read,write} are the default ki_retry methods for
|
|
* IO_CMD_P{READ,WRITE}. They maintains kiocb retry state around potentially
|
|
* multiple calls to f_op->aio_read(). They loop around partial progress
|
|
* instead of returning -EIOCBRETRY because they don't have the means to call
|
|
* kick_iocb().
|
|
*/
|
|
static ssize_t aio_pread(struct kiocb *iocb)
|
|
{
|
|
struct file *file = iocb->ki_filp;
|
|
struct address_space *mapping = file->f_mapping;
|
|
struct inode *inode = mapping->host;
|
|
ssize_t ret = 0;
|
|
|
|
do {
|
|
ret = file->f_op->aio_read(iocb, iocb->ki_buf,
|
|
iocb->ki_left, iocb->ki_pos);
|
|
/*
|
|
* Can't just depend on iocb->ki_left to determine
|
|
* whether we are done. This may have been a short read.
|
|
*/
|
|
if (ret > 0) {
|
|
iocb->ki_buf += ret;
|
|
iocb->ki_left -= ret;
|
|
}
|
|
|
|
/*
|
|
* For pipes and sockets we return once we have some data; for
|
|
* regular files we retry till we complete the entire read or
|
|
* find that we can't read any more data (e.g short reads).
|
|
*/
|
|
} while (ret > 0 && iocb->ki_left > 0 &&
|
|
!S_ISFIFO(inode->i_mode) && !S_ISSOCK(inode->i_mode));
|
|
|
|
/* This means we must have transferred all that we could */
|
|
/* No need to retry anymore */
|
|
if ((ret == 0) || (iocb->ki_left == 0))
|
|
ret = iocb->ki_nbytes - iocb->ki_left;
|
|
|
|
return ret;
|
|
}
|
|
|
|
/* see aio_pread() */
|
|
static ssize_t aio_pwrite(struct kiocb *iocb)
|
|
{
|
|
struct file *file = iocb->ki_filp;
|
|
ssize_t ret = 0;
|
|
|
|
do {
|
|
ret = file->f_op->aio_write(iocb, iocb->ki_buf,
|
|
iocb->ki_left, iocb->ki_pos);
|
|
if (ret > 0) {
|
|
iocb->ki_buf += ret;
|
|
iocb->ki_left -= ret;
|
|
}
|
|
} while (ret > 0 && iocb->ki_left > 0);
|
|
|
|
if ((ret == 0) || (iocb->ki_left == 0))
|
|
ret = iocb->ki_nbytes - iocb->ki_left;
|
|
|
|
return ret;
|
|
}
|
|
|
|
static ssize_t aio_fdsync(struct kiocb *iocb)
|
|
{
|
|
struct file *file = iocb->ki_filp;
|
|
ssize_t ret = -EINVAL;
|
|
|
|
if (file->f_op->aio_fsync)
|
|
ret = file->f_op->aio_fsync(iocb, 1);
|
|
return ret;
|
|
}
|
|
|
|
static ssize_t aio_fsync(struct kiocb *iocb)
|
|
{
|
|
struct file *file = iocb->ki_filp;
|
|
ssize_t ret = -EINVAL;
|
|
|
|
if (file->f_op->aio_fsync)
|
|
ret = file->f_op->aio_fsync(iocb, 0);
|
|
return ret;
|
|
}
|
|
|
|
/*
|
|
* aio_setup_iocb:
|
|
* Performs the initial checks and aio retry method
|
|
* setup for the kiocb at the time of io submission.
|
|
*/
|
|
static ssize_t aio_setup_iocb(struct kiocb *kiocb)
|
|
{
|
|
struct file *file = kiocb->ki_filp;
|
|
ssize_t ret = 0;
|
|
|
|
switch (kiocb->ki_opcode) {
|
|
case IOCB_CMD_PREAD:
|
|
ret = -EBADF;
|
|
if (unlikely(!(file->f_mode & FMODE_READ)))
|
|
break;
|
|
ret = -EFAULT;
|
|
if (unlikely(!access_ok(VERIFY_WRITE, kiocb->ki_buf,
|
|
kiocb->ki_left)))
|
|
break;
|
|
ret = security_file_permission(file, MAY_READ);
|
|
if (unlikely(ret))
|
|
break;
|
|
ret = -EINVAL;
|
|
if (file->f_op->aio_read)
|
|
kiocb->ki_retry = aio_pread;
|
|
break;
|
|
case IOCB_CMD_PWRITE:
|
|
ret = -EBADF;
|
|
if (unlikely(!(file->f_mode & FMODE_WRITE)))
|
|
break;
|
|
ret = -EFAULT;
|
|
if (unlikely(!access_ok(VERIFY_READ, kiocb->ki_buf,
|
|
kiocb->ki_left)))
|
|
break;
|
|
ret = security_file_permission(file, MAY_WRITE);
|
|
if (unlikely(ret))
|
|
break;
|
|
ret = -EINVAL;
|
|
if (file->f_op->aio_write)
|
|
kiocb->ki_retry = aio_pwrite;
|
|
break;
|
|
case IOCB_CMD_FDSYNC:
|
|
ret = -EINVAL;
|
|
if (file->f_op->aio_fsync)
|
|
kiocb->ki_retry = aio_fdsync;
|
|
break;
|
|
case IOCB_CMD_FSYNC:
|
|
ret = -EINVAL;
|
|
if (file->f_op->aio_fsync)
|
|
kiocb->ki_retry = aio_fsync;
|
|
break;
|
|
default:
|
|
dprintk("EINVAL: io_submit: no operation provided\n");
|
|
ret = -EINVAL;
|
|
}
|
|
|
|
if (!kiocb->ki_retry)
|
|
return ret;
|
|
|
|
return 0;
|
|
}
|
|
|
|
/*
|
|
* aio_wake_function:
|
|
* wait queue callback function for aio notification,
|
|
* Simply triggers a retry of the operation via kick_iocb.
|
|
*
|
|
* This callback is specified in the wait queue entry in
|
|
* a kiocb (current->io_wait points to this wait queue
|
|
* entry when an aio operation executes; it is used
|
|
* instead of a synchronous wait when an i/o blocking
|
|
* condition is encountered during aio).
|
|
*
|
|
* Note:
|
|
* This routine is executed with the wait queue lock held.
|
|
* Since kick_iocb acquires iocb->ctx->ctx_lock, it nests
|
|
* the ioctx lock inside the wait queue lock. This is safe
|
|
* because this callback isn't used for wait queues which
|
|
* are nested inside ioctx lock (i.e. ctx->wait)
|
|
*/
|
|
static int aio_wake_function(wait_queue_t *wait, unsigned mode,
|
|
int sync, void *key)
|
|
{
|
|
struct kiocb *iocb = container_of(wait, struct kiocb, ki_wait);
|
|
|
|
list_del_init(&wait->task_list);
|
|
kick_iocb(iocb);
|
|
return 1;
|
|
}
|
|
|
|
int fastcall io_submit_one(struct kioctx *ctx, struct iocb __user *user_iocb,
|
|
struct iocb *iocb)
|
|
{
|
|
struct kiocb *req;
|
|
struct file *file;
|
|
ssize_t ret;
|
|
|
|
/* enforce forwards compatibility on users */
|
|
if (unlikely(iocb->aio_reserved1 || iocb->aio_reserved2 ||
|
|
iocb->aio_reserved3)) {
|
|
pr_debug("EINVAL: io_submit: 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: io_submit: overflow check\n");
|
|
return -EINVAL;
|
|
}
|
|
|
|
file = fget(iocb->aio_fildes);
|
|
if (unlikely(!file))
|
|
return -EBADF;
|
|
|
|
req = aio_get_req(ctx); /* returns with 2 references to req */
|
|
if (unlikely(!req)) {
|
|
fput(file);
|
|
return -EAGAIN;
|
|
}
|
|
|
|
req->ki_filp = file;
|
|
ret = put_user(req->ki_key, &user_iocb->aio_key);
|
|
if (unlikely(ret)) {
|
|
dprintk("EFAULT: aio_key\n");
|
|
goto out_put_req;
|
|
}
|
|
|
|
req->ki_obj.user = user_iocb;
|
|
req->ki_user_data = iocb->aio_data;
|
|
req->ki_pos = iocb->aio_offset;
|
|
|
|
req->ki_buf = (char __user *)(unsigned long)iocb->aio_buf;
|
|
req->ki_left = req->ki_nbytes = iocb->aio_nbytes;
|
|
req->ki_opcode = iocb->aio_lio_opcode;
|
|
init_waitqueue_func_entry(&req->ki_wait, aio_wake_function);
|
|
INIT_LIST_HEAD(&req->ki_wait.task_list);
|
|
req->ki_retried = 0;
|
|
|
|
ret = aio_setup_iocb(req);
|
|
|
|
if (ret)
|
|
goto out_put_req;
|
|
|
|
spin_lock_irq(&ctx->ctx_lock);
|
|
aio_run_iocb(req);
|
|
if (!list_empty(&ctx->run_list)) {
|
|
/* drain the run list */
|
|
while (__aio_run_iocbs(ctx))
|
|
;
|
|
}
|
|
spin_unlock_irq(&ctx->ctx_lock);
|
|
aio_put_req(req); /* drop extra ref to req */
|
|
return 0;
|
|
|
|
out_put_req:
|
|
aio_put_req(req); /* drop extra ref to req */
|
|
aio_put_req(req); /* drop i/o ref to req */
|
|
return 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.
|
|
*/
|
|
asmlinkage long sys_io_submit(aio_context_t ctx_id, long nr,
|
|
struct iocb __user * __user *iocbpp)
|
|
{
|
|
struct kioctx *ctx;
|
|
long ret = 0;
|
|
int i;
|
|
|
|
if (unlikely(nr < 0))
|
|
return -EINVAL;
|
|
|
|
if (unlikely(!access_ok(VERIFY_READ, iocbpp, (nr*sizeof(*iocbpp)))))
|
|
return -EFAULT;
|
|
|
|
ctx = lookup_ioctx(ctx_id);
|
|
if (unlikely(!ctx)) {
|
|
pr_debug("EINVAL: io_submit: invalid context id\n");
|
|
return -EINVAL;
|
|
}
|
|
|
|
/*
|
|
* 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);
|
|
if (ret)
|
|
break;
|
|
}
|
|
|
|
put_ioctx(ctx);
|
|
return i ? i : ret;
|
|
}
|
|
|
|
/* lookup_kiocb
|
|
* Finds a given iocb for cancellation.
|
|
*/
|
|
static struct kiocb *lookup_kiocb(struct kioctx *ctx, struct iocb __user *iocb,
|
|
u32 key)
|
|
{
|
|
struct list_head *pos;
|
|
|
|
assert_spin_locked(&ctx->ctx_lock);
|
|
|
|
/* TODO: use a hash or array, this sucks. */
|
|
list_for_each(pos, &ctx->active_reqs) {
|
|
struct kiocb *kiocb = list_kiocb(pos);
|
|
if (kiocb->ki_obj.user == iocb && kiocb->ki_key == key)
|
|
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.
|
|
*/
|
|
asmlinkage long sys_io_cancel(aio_context_t ctx_id, struct iocb __user *iocb,
|
|
struct io_event __user *result)
|
|
{
|
|
int (*cancel)(struct kiocb *iocb, struct io_event *res);
|
|
struct kioctx *ctx;
|
|
struct 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);
|
|
ret = -EAGAIN;
|
|
kiocb = lookup_kiocb(ctx, iocb, key);
|
|
if (kiocb && kiocb->ki_cancel) {
|
|
cancel = kiocb->ki_cancel;
|
|
kiocb->ki_users ++;
|
|
kiocbSetCancelled(kiocb);
|
|
} else
|
|
cancel = NULL;
|
|
spin_unlock_irq(&ctx->ctx_lock);
|
|
|
|
if (NULL != cancel) {
|
|
struct io_event tmp;
|
|
pr_debug("calling cancel\n");
|
|
memset(&tmp, 0, sizeof(tmp));
|
|
tmp.obj = (u64)(unsigned long)kiocb->ki_obj.user;
|
|
tmp.data = kiocb->ki_user_data;
|
|
ret = cancel(kiocb, &tmp);
|
|
if (!ret) {
|
|
/* Cancellation succeeded -- copy the result
|
|
* into the user's buffer.
|
|
*/
|
|
if (copy_to_user(result, &tmp, sizeof(tmp)))
|
|
ret = -EFAULT;
|
|
}
|
|
} else
|
|
ret = -EINVAL;
|
|
|
|
put_ioctx(ctx);
|
|
|
|
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. May
|
|
* fail with -EINVAL if ctx_id is invalid, if min_nr is out of range,
|
|
* if nr is out of range, if when is out of range. May fail with
|
|
* -EFAULT if any of the memory specified to is invalid. May return
|
|
* 0 or < min_nr if no events are available and the timeout specified
|
|
* by when has elapsed, where when == NULL specifies an infinite
|
|
* timeout. Note that the timeout pointed to by when is relative and
|
|
* will be updated if not NULL and the operation blocks. Will fail
|
|
* with -ENOSYS if not implemented.
|
|
*/
|
|
asmlinkage long sys_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 && nr >= 0))
|
|
ret = read_events(ioctx, min_nr, nr, events, timeout);
|
|
put_ioctx(ioctx);
|
|
}
|
|
|
|
return ret;
|
|
}
|
|
|
|
__initcall(aio_setup);
|
|
|
|
EXPORT_SYMBOL(aio_complete);
|
|
EXPORT_SYMBOL(aio_put_req);
|
|
EXPORT_SYMBOL(wait_on_sync_kiocb);
|