![Kent Overstreet](/assets/img/avatar_default.png)
The usage of ctx->dead was fubar - it makes no sense to explicitly check it all over the place, especially when we're already using RCU. Now, ctx->dead only indicates whether we've dropped the initial refcount. The new teardown sequence is: set ctx->dead hlist_del_rcu(); synchronize_rcu(); Now we know no system calls can take a new ref, and it's safe to drop the initial ref: put_ioctx(); We also need to ensure there are no more outstanding kiocbs. This was done incorrectly - it was being done in kill_ctx(), and before dropping the initial refcount. At this point, other syscalls may still be submitting kiocbs! Now, we cancel and wait for outstanding kiocbs in free_ioctx(), after kioctx->users has dropped to 0 and we know no more iocbs could be submitted. [akpm@linux-foundation.org: coding-style fixes] Signed-off-by: Kent Overstreet <koverstreet@google.com> Cc: Zach Brown <zab@redhat.com> Cc: Felipe Balbi <balbi@ti.com> Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org> Cc: Mark Fasheh <mfasheh@suse.com> Cc: Joel Becker <jlbec@evilplan.org> Cc: Rusty Russell <rusty@rustcorp.com.au> Cc: Jens Axboe <axboe@kernel.dk> Cc: Asai Thambi S P <asamymuthupa@micron.com> Cc: Selvan Mani <smani@micron.com> Cc: Sam Bradshaw <sbradshaw@micron.com> Cc: Jeff Moyer <jmoyer@redhat.com> Cc: Al Viro <viro@zeniv.linux.org.uk> Cc: Benjamin LaHaise <bcrl@kvack.org> Reviewed-by: "Theodore Ts'o" <tytso@mit.edu> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
1498 lines
37 KiB
C
1498 lines
37 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/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 <asm/kmap_types.h>
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#include <asm/uaccess.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;
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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 aio_ring_info {
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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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spinlock_t ring_lock;
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long nr_pages;
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unsigned nr, tail;
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struct page *internal_pages[AIO_RING_PAGES];
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};
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static inline unsigned aio_ring_avail(struct aio_ring_info *info,
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struct aio_ring *ring)
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{
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return (ring->head + info->nr - 1 - ring->tail) % info->nr;
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}
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struct kioctx {
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atomic_t users;
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atomic_t dead;
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/* This needs improving */
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unsigned long user_id;
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struct hlist_node list;
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wait_queue_head_t wait;
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spinlock_t ctx_lock;
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atomic_t reqs_active;
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struct list_head active_reqs; /* used for cancellation */
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/* sys_io_setup currently limits this to an unsigned int */
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unsigned max_reqs;
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struct aio_ring_info ring_info;
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struct rcu_head rcu_head;
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struct work_struct rcu_work;
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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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/* 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(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 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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vm_munmap(info->mmap_base, info->mmap_size);
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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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struct mm_struct *mm = current->mm;
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unsigned long size, populate;
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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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pr_debug("attempting mmap of %lu bytes\n", info->mmap_size);
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down_write(&mm->mmap_sem);
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info->mmap_base = do_mmap_pgoff(NULL, 0, info->mmap_size,
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PROT_READ|PROT_WRITE,
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MAP_ANONYMOUS|MAP_PRIVATE, 0,
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&populate);
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if (IS_ERR((void *)info->mmap_base)) {
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up_write(&mm->mmap_sem);
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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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pr_debug("mmap address: 0x%08lx\n", info->mmap_base);
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info->nr_pages = get_user_pages(current, mm, info->mmap_base, nr_pages,
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1, 0, info->ring_pages, NULL);
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up_write(&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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if (populate)
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mm_populate(info->mmap_base, populate);
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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]);
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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);
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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(). 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) ({ \
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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]); \
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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) 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)); \
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} while(0)
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static int kiocb_cancel(struct kioctx *ctx, struct kiocb *kiocb,
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struct io_event *res)
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{
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int (*cancel)(struct kiocb *, struct io_event *);
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int ret = -EINVAL;
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cancel = kiocb->ki_cancel;
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kiocbSetCancelled(kiocb);
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if (cancel) {
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atomic_inc(&kiocb->ki_users);
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spin_unlock_irq(&ctx->ctx_lock);
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memset(res, 0, sizeof(*res));
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res->obj = (u64)(unsigned long)kiocb->ki_obj.user;
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res->data = kiocb->ki_user_data;
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ret = cancel(kiocb, res);
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spin_lock_irq(&ctx->ctx_lock);
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}
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return ret;
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}
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static void free_ioctx_rcu(struct rcu_head *head)
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{
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struct kioctx *ctx = container_of(head, struct kioctx, rcu_head);
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kmem_cache_free(kioctx_cachep, ctx);
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}
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/*
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* When this function runs, the kioctx has been removed from the "hash table"
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* and ctx->users has dropped to 0, so we know no more kiocbs can be submitted -
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* now it's safe to cancel any that need to be.
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*/
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static void free_ioctx(struct kioctx *ctx)
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{
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struct io_event res;
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struct kiocb *req;
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spin_lock_irq(&ctx->ctx_lock);
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while (!list_empty(&ctx->active_reqs)) {
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req = list_first_entry(&ctx->active_reqs,
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struct kiocb, ki_list);
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list_del_init(&req->ki_list);
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kiocb_cancel(ctx, req, &res);
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}
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spin_unlock_irq(&ctx->ctx_lock);
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wait_event(ctx->wait, !atomic_read(&ctx->reqs_active));
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aio_free_ring(ctx);
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spin_lock(&aio_nr_lock);
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BUG_ON(aio_nr - ctx->max_reqs > aio_nr);
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aio_nr -= ctx->max_reqs;
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spin_unlock(&aio_nr_lock);
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pr_debug("freeing %p\n", ctx);
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/*
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* Here the call_rcu() is between the wait_event() for reqs_active to
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* hit 0, and freeing the ioctx.
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*
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* aio_complete() decrements reqs_active, but it has to touch the ioctx
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* after to issue a wakeup so we use rcu.
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*/
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call_rcu(&ctx->rcu_head, free_ioctx_rcu);
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}
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static void put_ioctx(struct kioctx *ctx)
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{
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if (unlikely(atomic_dec_and_test(&ctx->users)))
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free_ioctx(ctx);
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}
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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 = current->mm;
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struct kioctx *ctx;
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int err = -ENOMEM;
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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 (!nr_events || (unsigned long)nr_events > aio_max_nr)
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return ERR_PTR(-EAGAIN);
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ctx = kmem_cache_zalloc(kioctx_cachep, GFP_KERNEL);
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if (!ctx)
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return ERR_PTR(-ENOMEM);
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ctx->max_reqs = nr_events;
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atomic_set(&ctx->users, 2);
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atomic_set(&ctx->dead, 0);
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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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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 + nr_events > aio_max_nr ||
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aio_nr + nr_events < aio_nr) {
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spin_unlock(&aio_nr_lock);
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goto out_cleanup;
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}
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aio_nr += ctx->max_reqs;
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spin_unlock(&aio_nr_lock);
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/* now link into global list. */
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spin_lock(&mm->ioctx_lock);
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hlist_add_head_rcu(&ctx->list, &mm->ioctx_list);
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spin_unlock(&mm->ioctx_lock);
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pr_debug("allocated ioctx %p[%ld]: mm=%p mask=0x%x\n",
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ctx, ctx->user_id, mm, ctx->ring_info.nr);
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return ctx;
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out_cleanup:
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err = -EAGAIN;
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aio_free_ring(ctx);
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out_freectx:
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kmem_cache_free(kioctx_cachep, ctx);
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pr_debug("error allocating ioctx %d\n", err);
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return ERR_PTR(err);
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}
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static void kill_ioctx_work(struct work_struct *work)
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{
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struct kioctx *ctx = container_of(work, struct kioctx, rcu_work);
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wake_up_all(&ctx->wait);
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put_ioctx(ctx);
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}
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static void kill_ioctx_rcu(struct rcu_head *head)
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{
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struct kioctx *ctx = container_of(head, struct kioctx, rcu_head);
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INIT_WORK(&ctx->rcu_work, kill_ioctx_work);
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schedule_work(&ctx->rcu_work);
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}
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/* kill_ioctx
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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 kill_ioctx(struct kioctx *ctx)
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{
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if (!atomic_xchg(&ctx->dead, 1)) {
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hlist_del_rcu(&ctx->list);
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/* Between hlist_del_rcu() and dropping the initial ref */
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synchronize_rcu();
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/*
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* We can't punt to workqueue here because put_ioctx() ->
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* free_ioctx() will unmap the ringbuffer, and that has to be
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* done in the original process's context. kill_ioctx_rcu/work()
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* exist for exit_aio(), as in that path free_ioctx() won't do
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* the unmap.
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*/
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kill_ioctx_work(&ctx->rcu_work);
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}
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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 wait_on_sync_kiocb(struct kiocb *iocb)
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{
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while (atomic_read(&iocb->ki_users)) {
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set_current_state(TASK_UNINTERRUPTIBLE);
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if (!atomic_read(&iocb->ki_users))
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break;
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io_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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EXPORT_SYMBOL(wait_on_sync_kiocb);
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|
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/*
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* exit_aio: called when the last user of mm goes away. At this point, there is
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* no way for any new requests to be submited or any of the io_* syscalls to be
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* called on the context.
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*
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* There may be outstanding kiocbs, but free_ioctx() will explicitly wait on
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* them.
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*/
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void exit_aio(struct mm_struct *mm)
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{
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struct kioctx *ctx;
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struct hlist_node *n;
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hlist_for_each_entry_safe(ctx, n, &mm->ioctx_list, list) {
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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),
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atomic_read(&ctx->dead),
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atomic_read(&ctx->reqs_active));
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/*
|
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* We don't need to bother with munmap() here -
|
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* exit_mmap(mm) is coming and it'll unmap everything.
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* Since aio_free_ring() uses non-zero ->mmap_size
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* as indicator that it needs to unmap the area,
|
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* just set it to 0; aio_free_ring() is the only
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* place that uses ->mmap_size, so it's safe.
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*/
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ctx->ring_info.mmap_size = 0;
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|
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if (!atomic_xchg(&ctx->dead, 1)) {
|
|
hlist_del_rcu(&ctx->list);
|
|
call_rcu(&ctx->rcu_head, kill_ioctx_rcu);
|
|
}
|
|
}
|
|
}
|
|
|
|
/* aio_get_req
|
|
* Allocate a slot for an aio request. Increments the ki_users count
|
|
* of the kioctx so that the kioctx stays around until all requests are
|
|
* complete. Returns NULL if no requests are free.
|
|
*
|
|
* Returns with kiocb->ki_users set to 2. The io submit code path holds
|
|
* an extra reference while submitting the i/o.
|
|
* This prevents races between the aio code path referencing the
|
|
* req (after submitting it) and aio_complete() freeing the req.
|
|
*/
|
|
static struct kiocb *__aio_get_req(struct kioctx *ctx)
|
|
{
|
|
struct kiocb *req = NULL;
|
|
|
|
req = kmem_cache_alloc(kiocb_cachep, GFP_KERNEL);
|
|
if (unlikely(!req))
|
|
return NULL;
|
|
|
|
req->ki_flags = 0;
|
|
atomic_set(&req->ki_users, 2);
|
|
req->ki_key = 0;
|
|
req->ki_ctx = ctx;
|
|
req->ki_cancel = NULL;
|
|
req->ki_retry = NULL;
|
|
req->ki_dtor = NULL;
|
|
req->private = NULL;
|
|
req->ki_iovec = NULL;
|
|
req->ki_eventfd = NULL;
|
|
|
|
return req;
|
|
}
|
|
|
|
/*
|
|
* struct kiocb's are allocated in batches to reduce the number of
|
|
* times the ctx lock is acquired and released.
|
|
*/
|
|
#define KIOCB_BATCH_SIZE 32L
|
|
struct kiocb_batch {
|
|
struct list_head head;
|
|
long count; /* number of requests left to allocate */
|
|
};
|
|
|
|
static void kiocb_batch_init(struct kiocb_batch *batch, long total)
|
|
{
|
|
INIT_LIST_HEAD(&batch->head);
|
|
batch->count = total;
|
|
}
|
|
|
|
static void kiocb_batch_free(struct kioctx *ctx, struct kiocb_batch *batch)
|
|
{
|
|
struct kiocb *req, *n;
|
|
|
|
if (list_empty(&batch->head))
|
|
return;
|
|
|
|
spin_lock_irq(&ctx->ctx_lock);
|
|
list_for_each_entry_safe(req, n, &batch->head, ki_batch) {
|
|
list_del(&req->ki_batch);
|
|
list_del(&req->ki_list);
|
|
kmem_cache_free(kiocb_cachep, req);
|
|
atomic_dec(&ctx->reqs_active);
|
|
}
|
|
spin_unlock_irq(&ctx->ctx_lock);
|
|
}
|
|
|
|
/*
|
|
* Allocate a batch of kiocbs. This avoids taking and dropping the
|
|
* context lock a lot during setup.
|
|
*/
|
|
static int kiocb_batch_refill(struct kioctx *ctx, struct kiocb_batch *batch)
|
|
{
|
|
unsigned short allocated, to_alloc;
|
|
long avail;
|
|
struct kiocb *req, *n;
|
|
struct aio_ring *ring;
|
|
|
|
to_alloc = min(batch->count, KIOCB_BATCH_SIZE);
|
|
for (allocated = 0; allocated < to_alloc; allocated++) {
|
|
req = __aio_get_req(ctx);
|
|
if (!req)
|
|
/* allocation failed, go with what we've got */
|
|
break;
|
|
list_add(&req->ki_batch, &batch->head);
|
|
}
|
|
|
|
if (allocated == 0)
|
|
goto out;
|
|
|
|
spin_lock_irq(&ctx->ctx_lock);
|
|
ring = kmap_atomic(ctx->ring_info.ring_pages[0]);
|
|
|
|
avail = aio_ring_avail(&ctx->ring_info, ring) -
|
|
atomic_read(&ctx->reqs_active);
|
|
BUG_ON(avail < 0);
|
|
if (avail < allocated) {
|
|
/* Trim back the number of requests. */
|
|
list_for_each_entry_safe(req, n, &batch->head, ki_batch) {
|
|
list_del(&req->ki_batch);
|
|
kmem_cache_free(kiocb_cachep, req);
|
|
if (--allocated <= avail)
|
|
break;
|
|
}
|
|
}
|
|
|
|
batch->count -= allocated;
|
|
list_for_each_entry(req, &batch->head, ki_batch) {
|
|
list_add(&req->ki_list, &ctx->active_reqs);
|
|
atomic_inc(&ctx->reqs_active);
|
|
}
|
|
|
|
kunmap_atomic(ring);
|
|
spin_unlock_irq(&ctx->ctx_lock);
|
|
|
|
out:
|
|
return allocated;
|
|
}
|
|
|
|
static inline struct kiocb *aio_get_req(struct kioctx *ctx,
|
|
struct kiocb_batch *batch)
|
|
{
|
|
struct kiocb *req;
|
|
|
|
if (list_empty(&batch->head))
|
|
if (kiocb_batch_refill(ctx, batch) == 0)
|
|
return NULL;
|
|
req = list_first_entry(&batch->head, struct kiocb, ki_batch);
|
|
list_del(&req->ki_batch);
|
|
return req;
|
|
}
|
|
|
|
static void kiocb_free(struct kiocb *req)
|
|
{
|
|
if (req->ki_filp)
|
|
fput(req->ki_filp);
|
|
if (req->ki_eventfd != NULL)
|
|
eventfd_ctx_put(req->ki_eventfd);
|
|
if (req->ki_dtor)
|
|
req->ki_dtor(req);
|
|
if (req->ki_iovec != &req->ki_inline_vec)
|
|
kfree(req->ki_iovec);
|
|
kmem_cache_free(kiocb_cachep, req);
|
|
}
|
|
|
|
void aio_put_req(struct kiocb *req)
|
|
{
|
|
if (atomic_dec_and_test(&req->ki_users))
|
|
kiocb_free(req);
|
|
}
|
|
EXPORT_SYMBOL(aio_put_req);
|
|
|
|
static struct kioctx *lookup_ioctx(unsigned long ctx_id)
|
|
{
|
|
struct mm_struct *mm = current->mm;
|
|
struct kioctx *ctx, *ret = NULL;
|
|
|
|
rcu_read_lock();
|
|
|
|
hlist_for_each_entry_rcu(ctx, &mm->ioctx_list, list) {
|
|
if (ctx->user_id == ctx_id) {
|
|
atomic_inc(&ctx->users);
|
|
ret = ctx;
|
|
break;
|
|
}
|
|
}
|
|
|
|
rcu_read_unlock();
|
|
return ret;
|
|
}
|
|
|
|
/* aio_complete
|
|
* Called when the io request on the given iocb is complete.
|
|
*/
|
|
void 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;
|
|
|
|
/*
|
|
* 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(atomic_read(&iocb->ki_users) != 1);
|
|
iocb->ki_user_data = res;
|
|
atomic_set(&iocb->ki_users, 0);
|
|
wake_up_process(iocb->ki_obj.tsk);
|
|
return;
|
|
}
|
|
|
|
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.
|
|
*
|
|
* Take rcu_read_lock() in case the kioctx is being destroyed, as we
|
|
* need to issue a wakeup after decrementing reqs_active.
|
|
*/
|
|
rcu_read_lock();
|
|
spin_lock_irqsave(&ctx->ctx_lock, flags);
|
|
|
|
list_del(&iocb->ki_list); /* remove from active_reqs */
|
|
|
|
/*
|
|
* 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]);
|
|
|
|
tail = info->tail;
|
|
event = aio_ring_event(info, tail);
|
|
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;
|
|
|
|
pr_debug("%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);
|
|
kunmap_atomic(ring);
|
|
|
|
pr_debug("added to ring %p at [%lu]\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);
|
|
|
|
put_rq:
|
|
/* everything turned out well, dispose of the aiocb. */
|
|
aio_put_req(iocb);
|
|
atomic_dec(&ctx->reqs_active);
|
|
|
|
/*
|
|
* 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);
|
|
|
|
spin_unlock_irqrestore(&ctx->ctx_lock, flags);
|
|
rcu_read_unlock();
|
|
}
|
|
EXPORT_SYMBOL(aio_complete);
|
|
|
|
/* 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]);
|
|
pr_debug("h%u t%u m%u\n", ring->head, ring->tail, 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);
|
|
*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);
|
|
}
|
|
spin_unlock(&info->ring_lock);
|
|
|
|
out:
|
|
kunmap_atomic(ring);
|
|
pr_debug("%d h%u t%u\n", ret, ring->head, 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)
|
|
{
|
|
setup_timer_on_stack(&to->timer, timeout_func, (unsigned long) to);
|
|
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;
|
|
|
|
/* needed to zero any padding within an entry (there shouldn't be
|
|
* any, but C is fun!
|
|
*/
|
|
memset(&ent, 0, sizeof(ent));
|
|
ret = 0;
|
|
while (likely(i < nr)) {
|
|
ret = aio_read_evt(ctx, &ent);
|
|
if (unlikely(ret <= 0))
|
|
break;
|
|
|
|
pr_debug("%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)))) {
|
|
pr_debug("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 */
|
|
|
|
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;
|
|
if (unlikely(atomic_read(&ctx->dead))) {
|
|
ret = -EINVAL;
|
|
break;
|
|
}
|
|
if (to.timed_out) /* Only check after read evt */
|
|
break;
|
|
/* Try to only show up in io wait if there are ops
|
|
* in flight */
|
|
if (atomic_read(&ctx->reqs_active))
|
|
io_schedule();
|
|
else
|
|
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)))) {
|
|
pr_debug("lost an event due to EFAULT.\n");
|
|
break;
|
|
}
|
|
|
|
/* Good, event copied to userland, update counts. */
|
|
event ++;
|
|
i ++;
|
|
}
|
|
|
|
if (timeout)
|
|
clear_timeout(&to);
|
|
out:
|
|
destroy_timer_on_stack(&to.timer);
|
|
return i ? i : 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: 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)
|
|
kill_ioctx(ioctx);
|
|
put_ioctx(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 -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)) {
|
|
kill_ioctx(ioctx);
|
|
put_ioctx(ioctx);
|
|
return 0;
|
|
}
|
|
pr_debug("EINVAL: io_destroy: invalid context id\n");
|
|
return -EINVAL;
|
|
}
|
|
|
|
static void aio_advance_iovec(struct kiocb *iocb, ssize_t ret)
|
|
{
|
|
struct iovec *iov = &iocb->ki_iovec[iocb->ki_cur_seg];
|
|
|
|
BUG_ON(ret <= 0);
|
|
|
|
while (iocb->ki_cur_seg < iocb->ki_nr_segs && ret > 0) {
|
|
ssize_t this = min((ssize_t)iov->iov_len, ret);
|
|
iov->iov_base += this;
|
|
iov->iov_len -= this;
|
|
iocb->ki_left -= this;
|
|
ret -= this;
|
|
if (iov->iov_len == 0) {
|
|
iocb->ki_cur_seg++;
|
|
iov++;
|
|
}
|
|
}
|
|
|
|
/* the caller should not have done more io than what fit in
|
|
* the remaining iovecs */
|
|
BUG_ON(ret > 0 && iocb->ki_left == 0);
|
|
}
|
|
|
|
static ssize_t aio_rw_vect_retry(struct kiocb *iocb)
|
|
{
|
|
struct file *file = iocb->ki_filp;
|
|
struct address_space *mapping = file->f_mapping;
|
|
struct inode *inode = mapping->host;
|
|
ssize_t (*rw_op)(struct kiocb *, const struct iovec *,
|
|
unsigned long, loff_t);
|
|
ssize_t ret = 0;
|
|
unsigned short opcode;
|
|
|
|
if ((iocb->ki_opcode == IOCB_CMD_PREADV) ||
|
|
(iocb->ki_opcode == IOCB_CMD_PREAD)) {
|
|
rw_op = file->f_op->aio_read;
|
|
opcode = IOCB_CMD_PREADV;
|
|
} else {
|
|
rw_op = file->f_op->aio_write;
|
|
opcode = IOCB_CMD_PWRITEV;
|
|
}
|
|
|
|
/* This matches the pread()/pwrite() logic */
|
|
if (iocb->ki_pos < 0)
|
|
return -EINVAL;
|
|
|
|
if (opcode == IOCB_CMD_PWRITEV)
|
|
file_start_write(file);
|
|
do {
|
|
ret = rw_op(iocb, &iocb->ki_iovec[iocb->ki_cur_seg],
|
|
iocb->ki_nr_segs - iocb->ki_cur_seg,
|
|
iocb->ki_pos);
|
|
if (ret > 0)
|
|
aio_advance_iovec(iocb, ret);
|
|
|
|
/* retry all partial writes. retry partial reads as long as its a
|
|
* regular file. */
|
|
} while (ret > 0 && iocb->ki_left > 0 &&
|
|
(opcode == IOCB_CMD_PWRITEV ||
|
|
(!S_ISFIFO(inode->i_mode) && !S_ISSOCK(inode->i_mode))));
|
|
if (opcode == IOCB_CMD_PWRITEV)
|
|
file_end_write(file);
|
|
|
|
/* 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;
|
|
|
|
/* If we managed to write some out we return that, rather than
|
|
* the eventual error. */
|
|
if (opcode == IOCB_CMD_PWRITEV
|
|
&& ret < 0 && ret != -EIOCBQUEUED
|
|
&& iocb->ki_nbytes - iocb->ki_left)
|
|
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;
|
|
}
|
|
|
|
static ssize_t aio_setup_vectored_rw(int type, struct kiocb *kiocb, bool compat)
|
|
{
|
|
ssize_t ret;
|
|
|
|
#ifdef CONFIG_COMPAT
|
|
if (compat)
|
|
ret = compat_rw_copy_check_uvector(type,
|
|
(struct compat_iovec __user *)kiocb->ki_buf,
|
|
kiocb->ki_nbytes, 1, &kiocb->ki_inline_vec,
|
|
&kiocb->ki_iovec);
|
|
else
|
|
#endif
|
|
ret = rw_copy_check_uvector(type,
|
|
(struct iovec __user *)kiocb->ki_buf,
|
|
kiocb->ki_nbytes, 1, &kiocb->ki_inline_vec,
|
|
&kiocb->ki_iovec);
|
|
if (ret < 0)
|
|
goto out;
|
|
|
|
ret = rw_verify_area(type, kiocb->ki_filp, &kiocb->ki_pos, ret);
|
|
if (ret < 0)
|
|
goto out;
|
|
|
|
kiocb->ki_nr_segs = kiocb->ki_nbytes;
|
|
kiocb->ki_cur_seg = 0;
|
|
/* ki_nbytes/left now reflect bytes instead of segs */
|
|
kiocb->ki_nbytes = ret;
|
|
kiocb->ki_left = ret;
|
|
|
|
ret = 0;
|
|
out:
|
|
return ret;
|
|
}
|
|
|
|
static ssize_t aio_setup_single_vector(int type, struct file * file, struct kiocb *kiocb)
|
|
{
|
|
int bytes;
|
|
|
|
bytes = rw_verify_area(type, file, &kiocb->ki_pos, kiocb->ki_left);
|
|
if (bytes < 0)
|
|
return bytes;
|
|
|
|
kiocb->ki_iovec = &kiocb->ki_inline_vec;
|
|
kiocb->ki_iovec->iov_base = kiocb->ki_buf;
|
|
kiocb->ki_iovec->iov_len = bytes;
|
|
kiocb->ki_nr_segs = 1;
|
|
kiocb->ki_cur_seg = 0;
|
|
return 0;
|
|
}
|
|
|
|
/*
|
|
* 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, bool compat)
|
|
{
|
|
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 = aio_setup_single_vector(READ, file, kiocb);
|
|
if (ret)
|
|
break;
|
|
ret = -EINVAL;
|
|
if (file->f_op->aio_read)
|
|
kiocb->ki_retry = aio_rw_vect_retry;
|
|
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 = aio_setup_single_vector(WRITE, file, kiocb);
|
|
if (ret)
|
|
break;
|
|
ret = -EINVAL;
|
|
if (file->f_op->aio_write)
|
|
kiocb->ki_retry = aio_rw_vect_retry;
|
|
break;
|
|
case IOCB_CMD_PREADV:
|
|
ret = -EBADF;
|
|
if (unlikely(!(file->f_mode & FMODE_READ)))
|
|
break;
|
|
ret = aio_setup_vectored_rw(READ, kiocb, compat);
|
|
if (ret)
|
|
break;
|
|
ret = -EINVAL;
|
|
if (file->f_op->aio_read)
|
|
kiocb->ki_retry = aio_rw_vect_retry;
|
|
break;
|
|
case IOCB_CMD_PWRITEV:
|
|
ret = -EBADF;
|
|
if (unlikely(!(file->f_mode & FMODE_WRITE)))
|
|
break;
|
|
ret = aio_setup_vectored_rw(WRITE, kiocb, compat);
|
|
if (ret)
|
|
break;
|
|
ret = -EINVAL;
|
|
if (file->f_op->aio_write)
|
|
kiocb->ki_retry = aio_rw_vect_retry;
|
|
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:
|
|
pr_debug("EINVAL: no operation provided\n");
|
|
ret = -EINVAL;
|
|
}
|
|
|
|
if (!kiocb->ki_retry)
|
|
return ret;
|
|
|
|
return 0;
|
|
}
|
|
|
|
static int io_submit_one(struct kioctx *ctx, struct iocb __user *user_iocb,
|
|
struct iocb *iocb, struct kiocb_batch *batch,
|
|
bool compat)
|
|
{
|
|
struct kiocb *req;
|
|
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: io_submit: overflow check\n");
|
|
return -EINVAL;
|
|
}
|
|
|
|
req = aio_get_req(ctx, batch); /* returns with 2 references to req */
|
|
if (unlikely(!req))
|
|
return -EAGAIN;
|
|
|
|
req->ki_filp = fget(iocb->aio_fildes);
|
|
if (unlikely(!req->ki_filp)) {
|
|
ret = -EBADF;
|
|
goto out_put_req;
|
|
}
|
|
|
|
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;
|
|
}
|
|
}
|
|
|
|
ret = put_user(req->ki_key, &user_iocb->aio_key);
|
|
if (unlikely(ret)) {
|
|
pr_debug("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;
|
|
|
|
ret = aio_setup_iocb(req, compat);
|
|
|
|
if (ret)
|
|
goto out_put_req;
|
|
|
|
if (unlikely(kiocbIsCancelled(req)))
|
|
ret = -EINTR;
|
|
else
|
|
ret = req->ki_retry(req);
|
|
|
|
if (ret != -EIOCBQUEUED) {
|
|
/*
|
|
* There's no easy way to restart the syscall since other AIO's
|
|
* may be already running. Just fail this IO with EINTR.
|
|
*/
|
|
if (unlikely(ret == -ERESTARTSYS || ret == -ERESTARTNOINTR ||
|
|
ret == -ERESTARTNOHAND ||
|
|
ret == -ERESTART_RESTARTBLOCK))
|
|
ret = -EINTR;
|
|
aio_complete(req, ret, 0);
|
|
}
|
|
|
|
aio_put_req(req); /* drop extra ref to req */
|
|
return 0;
|
|
|
|
out_put_req:
|
|
spin_lock_irq(&ctx->ctx_lock);
|
|
list_del(&req->ki_list);
|
|
spin_unlock_irq(&ctx->ctx_lock);
|
|
|
|
atomic_dec(&ctx->reqs_active);
|
|
aio_put_req(req); /* drop extra ref to req */
|
|
aio_put_req(req); /* drop i/o ref to req */
|
|
return ret;
|
|
}
|
|
|
|
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;
|
|
struct kiocb_batch batch;
|
|
|
|
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;
|
|
}
|
|
|
|
kiocb_batch_init(&batch, nr);
|
|
|
|
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, &batch, compat);
|
|
if (ret)
|
|
break;
|
|
}
|
|
blk_finish_plug(&plug);
|
|
|
|
kiocb_batch_free(ctx, &batch);
|
|
put_ioctx(ctx);
|
|
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);
|
|
}
|
|
|
|
/* 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.
|
|
*/
|
|
SYSCALL_DEFINE3(io_cancel, aio_context_t, ctx_id, struct iocb __user *, iocb,
|
|
struct io_event __user *, result)
|
|
{
|
|
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);
|
|
|
|
kiocb = lookup_kiocb(ctx, iocb, key);
|
|
if (kiocb)
|
|
ret = kiocb_cancel(ctx, kiocb, &res);
|
|
else
|
|
ret = -EINVAL;
|
|
|
|
spin_unlock_irq(&ctx->ctx_lock);
|
|
|
|
if (!ret) {
|
|
/* Cancellation succeeded -- copy the result
|
|
* into the user's buffer.
|
|
*/
|
|
if (copy_to_user(result, &res, sizeof(res)))
|
|
ret = -EFAULT;
|
|
}
|
|
|
|
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. 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 and will be updated if not NULL and the
|
|
* operation blocks. 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);
|
|
put_ioctx(ioctx);
|
|
}
|
|
return ret;
|
|
}
|