linux/fs/aio.c
Sasha Levin b67bfe0d42 hlist: drop the node parameter from iterators
I'm not sure why, but the hlist for each entry iterators were conceived

        list_for_each_entry(pos, head, member)

The hlist ones were greedy and wanted an extra parameter:

        hlist_for_each_entry(tpos, pos, head, member)

Why did they need an extra pos parameter? I'm not quite sure. Not only
they don't really need it, it also prevents the iterator from looking
exactly like the list iterator, which is unfortunate.

Besides the semantic patch, there was some manual work required:

 - Fix up the actual hlist iterators in linux/list.h
 - Fix up the declaration of other iterators based on the hlist ones.
 - A very small amount of places were using the 'node' parameter, this
 was modified to use 'obj->member' instead.
 - Coccinelle didn't handle the hlist_for_each_entry_safe iterator
 properly, so those had to be fixed up manually.

The semantic patch which is mostly the work of Peter Senna Tschudin is here:

@@
iterator name hlist_for_each_entry, hlist_for_each_entry_continue, hlist_for_each_entry_from, hlist_for_each_entry_rcu, hlist_for_each_entry_rcu_bh, hlist_for_each_entry_continue_rcu_bh, for_each_busy_worker, ax25_uid_for_each, ax25_for_each, inet_bind_bucket_for_each, sctp_for_each_hentry, sk_for_each, sk_for_each_rcu, sk_for_each_from, sk_for_each_safe, sk_for_each_bound, hlist_for_each_entry_safe, hlist_for_each_entry_continue_rcu, nr_neigh_for_each, nr_neigh_for_each_safe, nr_node_for_each, nr_node_for_each_safe, for_each_gfn_indirect_valid_sp, for_each_gfn_sp, for_each_host;

type T;
expression a,c,d,e;
identifier b;
statement S;
@@

-T b;
    <+... when != b
(
hlist_for_each_entry(a,
- b,
c, d) S
|
hlist_for_each_entry_continue(a,
- b,
c) S
|
hlist_for_each_entry_from(a,
- b,
c) S
|
hlist_for_each_entry_rcu(a,
- b,
c, d) S
|
hlist_for_each_entry_rcu_bh(a,
- b,
c, d) S
|
hlist_for_each_entry_continue_rcu_bh(a,
- b,
c) S
|
for_each_busy_worker(a, c,
- b,
d) S
|
ax25_uid_for_each(a,
- b,
c) S
|
ax25_for_each(a,
- b,
c) S
|
inet_bind_bucket_for_each(a,
- b,
c) S
|
sctp_for_each_hentry(a,
- b,
c) S
|
sk_for_each(a,
- b,
c) S
|
sk_for_each_rcu(a,
- b,
c) S
|
sk_for_each_from
-(a, b)
+(a)
S
+ sk_for_each_from(a) S
|
sk_for_each_safe(a,
- b,
c, d) S
|
sk_for_each_bound(a,
- b,
c) S
|
hlist_for_each_entry_safe(a,
- b,
c, d, e) S
|
hlist_for_each_entry_continue_rcu(a,
- b,
c) S
|
nr_neigh_for_each(a,
- b,
c) S
|
nr_neigh_for_each_safe(a,
- b,
c, d) S
|
nr_node_for_each(a,
- b,
c) S
|
nr_node_for_each_safe(a,
- b,
c, d) S
|
- for_each_gfn_sp(a, c, d, b) S
+ for_each_gfn_sp(a, c, d) S
|
- for_each_gfn_indirect_valid_sp(a, c, d, b) S
+ for_each_gfn_indirect_valid_sp(a, c, d) S
|
for_each_host(a,
- b,
c) S
|
for_each_host_safe(a,
- b,
c, d) S
|
for_each_mesh_entry(a,
- b,
c, d) S
)
    ...+>

[akpm@linux-foundation.org: drop bogus change from net/ipv4/raw.c]
[akpm@linux-foundation.org: drop bogus hunk from net/ipv6/raw.c]
[akpm@linux-foundation.org: checkpatch fixes]
[akpm@linux-foundation.org: fix warnings]
[akpm@linux-foudnation.org: redo intrusive kvm changes]
Tested-by: Peter Senna Tschudin <peter.senna@gmail.com>
Acked-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Signed-off-by: Sasha Levin <sasha.levin@oracle.com>
Cc: Wu Fengguang <fengguang.wu@intel.com>
Cc: Marcelo Tosatti <mtosatti@redhat.com>
Cc: Gleb Natapov <gleb@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2013-02-27 19:10:24 -08:00

1797 lines
46 KiB
C

/*
* An async IO implementation for Linux
* Written by Benjamin LaHaise <bcrl@kvack.org>
*
* Implements an efficient asynchronous io interface.
*
* Copyright 2000, 2001, 2002 Red Hat, Inc. All Rights Reserved.
*
* See ../COPYING for licensing terms.
*/
#include <linux/kernel.h>
#include <linux/init.h>
#include <linux/errno.h>
#include <linux/time.h>
#include <linux/aio_abi.h>
#include <linux/export.h>
#include <linux/syscalls.h>
#include <linux/backing-dev.h>
#include <linux/uio.h>
#define DEBUG 0
#include <linux/sched.h>
#include <linux/fs.h>
#include <linux/file.h>
#include <linux/mm.h>
#include <linux/mman.h>
#include <linux/mmu_context.h>
#include <linux/slab.h>
#include <linux/timer.h>
#include <linux/aio.h>
#include <linux/highmem.h>
#include <linux/workqueue.h>
#include <linux/security.h>
#include <linux/eventfd.h>
#include <linux/blkdev.h>
#include <linux/compat.h>
#include <asm/kmap_types.h>
#include <asm/uaccess.h>
#if DEBUG > 1
#define dprintk printk
#else
#define dprintk(x...) do { ; } while (0)
#endif
/*------ sysctl variables----*/
static DEFINE_SPINLOCK(aio_nr_lock);
unsigned long aio_nr; /* current system wide number of aio requests */
unsigned long aio_max_nr = 0x10000; /* system wide maximum number of aio requests */
/*----end sysctl variables---*/
static struct kmem_cache *kiocb_cachep;
static struct kmem_cache *kioctx_cachep;
static struct workqueue_struct *aio_wq;
static void aio_kick_handler(struct work_struct *);
static void aio_queue_work(struct kioctx *);
/* aio_setup
* Creates the slab caches used by the aio routines, panic on
* failure as this is done early during the boot sequence.
*/
static int __init aio_setup(void)
{
kiocb_cachep = KMEM_CACHE(kiocb, SLAB_HWCACHE_ALIGN|SLAB_PANIC);
kioctx_cachep = KMEM_CACHE(kioctx,SLAB_HWCACHE_ALIGN|SLAB_PANIC);
aio_wq = alloc_workqueue("aio", 0, 1); /* used to limit concurrency */
BUG_ON(!aio_wq);
pr_debug("aio_setup: sizeof(struct page) = %d\n", (int)sizeof(struct page));
return 0;
}
__initcall(aio_setup);
static void aio_free_ring(struct kioctx *ctx)
{
struct aio_ring_info *info = &ctx->ring_info;
long i;
for (i=0; i<info->nr_pages; i++)
put_page(info->ring_pages[i]);
if (info->mmap_size) {
BUG_ON(ctx->mm != current->mm);
vm_munmap(info->mmap_base, info->mmap_size);
}
if (info->ring_pages && info->ring_pages != info->internal_pages)
kfree(info->ring_pages);
info->ring_pages = NULL;
info->nr = 0;
}
static int aio_setup_ring(struct kioctx *ctx)
{
struct aio_ring *ring;
struct aio_ring_info *info = &ctx->ring_info;
unsigned nr_events = ctx->max_reqs;
unsigned long size, populate;
int nr_pages;
/* Compensate for the ring buffer's head/tail overlap entry */
nr_events += 2; /* 1 is required, 2 for good luck */
size = sizeof(struct aio_ring);
size += sizeof(struct io_event) * nr_events;
nr_pages = (size + PAGE_SIZE-1) >> PAGE_SHIFT;
if (nr_pages < 0)
return -EINVAL;
nr_events = (PAGE_SIZE * nr_pages - sizeof(struct aio_ring)) / sizeof(struct io_event);
info->nr = 0;
info->ring_pages = info->internal_pages;
if (nr_pages > AIO_RING_PAGES) {
info->ring_pages = kcalloc(nr_pages, sizeof(struct page *), GFP_KERNEL);
if (!info->ring_pages)
return -ENOMEM;
}
info->mmap_size = nr_pages * PAGE_SIZE;
dprintk("attempting mmap of %lu bytes\n", info->mmap_size);
down_write(&ctx->mm->mmap_sem);
info->mmap_base = do_mmap_pgoff(NULL, 0, info->mmap_size,
PROT_READ|PROT_WRITE,
MAP_ANONYMOUS|MAP_PRIVATE, 0,
&populate);
if (IS_ERR((void *)info->mmap_base)) {
up_write(&ctx->mm->mmap_sem);
info->mmap_size = 0;
aio_free_ring(ctx);
return -EAGAIN;
}
dprintk("mmap address: 0x%08lx\n", info->mmap_base);
info->nr_pages = get_user_pages(current, ctx->mm,
info->mmap_base, nr_pages,
1, 0, info->ring_pages, NULL);
up_write(&ctx->mm->mmap_sem);
if (unlikely(info->nr_pages != nr_pages)) {
aio_free_ring(ctx);
return -EAGAIN;
}
if (populate)
mm_populate(info->mmap_base, populate);
ctx->user_id = info->mmap_base;
info->nr = nr_events; /* trusted copy */
ring = kmap_atomic(info->ring_pages[0]);
ring->nr = nr_events; /* user copy */
ring->id = ctx->user_id;
ring->head = ring->tail = 0;
ring->magic = AIO_RING_MAGIC;
ring->compat_features = AIO_RING_COMPAT_FEATURES;
ring->incompat_features = AIO_RING_INCOMPAT_FEATURES;
ring->header_length = sizeof(struct aio_ring);
kunmap_atomic(ring);
return 0;
}
/* aio_ring_event: returns a pointer to the event at the given index from
* kmap_atomic(). Release the pointer with put_aio_ring_event();
*/
#define AIO_EVENTS_PER_PAGE (PAGE_SIZE / sizeof(struct io_event))
#define AIO_EVENTS_FIRST_PAGE ((PAGE_SIZE - sizeof(struct aio_ring)) / sizeof(struct io_event))
#define AIO_EVENTS_OFFSET (AIO_EVENTS_PER_PAGE - AIO_EVENTS_FIRST_PAGE)
#define aio_ring_event(info, nr) ({ \
unsigned pos = (nr) + AIO_EVENTS_OFFSET; \
struct io_event *__event; \
__event = kmap_atomic( \
(info)->ring_pages[pos / AIO_EVENTS_PER_PAGE]); \
__event += pos % AIO_EVENTS_PER_PAGE; \
__event; \
})
#define put_aio_ring_event(event) do { \
struct io_event *__event = (event); \
(void)__event; \
kunmap_atomic((void *)((unsigned long)__event & PAGE_MASK)); \
} while(0)
static void ctx_rcu_free(struct rcu_head *head)
{
struct kioctx *ctx = container_of(head, struct kioctx, rcu_head);
kmem_cache_free(kioctx_cachep, ctx);
}
/* __put_ioctx
* Called when the last user of an aio context has gone away,
* and the struct needs to be freed.
*/
static void __put_ioctx(struct kioctx *ctx)
{
unsigned nr_events = ctx->max_reqs;
BUG_ON(ctx->reqs_active);
cancel_delayed_work_sync(&ctx->wq);
aio_free_ring(ctx);
mmdrop(ctx->mm);
ctx->mm = NULL;
if (nr_events) {
spin_lock(&aio_nr_lock);
BUG_ON(aio_nr - nr_events > aio_nr);
aio_nr -= nr_events;
spin_unlock(&aio_nr_lock);
}
pr_debug("__put_ioctx: freeing %p\n", ctx);
call_rcu(&ctx->rcu_head, ctx_rcu_free);
}
static inline int try_get_ioctx(struct kioctx *kioctx)
{
return atomic_inc_not_zero(&kioctx->users);
}
static inline void put_ioctx(struct kioctx *kioctx)
{
BUG_ON(atomic_read(&kioctx->users) <= 0);
if (unlikely(atomic_dec_and_test(&kioctx->users)))
__put_ioctx(kioctx);
}
/* ioctx_alloc
* Allocates and initializes an ioctx. Returns an ERR_PTR if it failed.
*/
static struct kioctx *ioctx_alloc(unsigned nr_events)
{
struct mm_struct *mm;
struct kioctx *ctx;
int err = -ENOMEM;
/* Prevent overflows */
if ((nr_events > (0x10000000U / sizeof(struct io_event))) ||
(nr_events > (0x10000000U / sizeof(struct kiocb)))) {
pr_debug("ENOMEM: nr_events too high\n");
return ERR_PTR(-EINVAL);
}
if (!nr_events || (unsigned long)nr_events > aio_max_nr)
return ERR_PTR(-EAGAIN);
ctx = kmem_cache_zalloc(kioctx_cachep, GFP_KERNEL);
if (!ctx)
return ERR_PTR(-ENOMEM);
ctx->max_reqs = nr_events;
mm = ctx->mm = current->mm;
atomic_inc(&mm->mm_count);
atomic_set(&ctx->users, 2);
spin_lock_init(&ctx->ctx_lock);
spin_lock_init(&ctx->ring_info.ring_lock);
init_waitqueue_head(&ctx->wait);
INIT_LIST_HEAD(&ctx->active_reqs);
INIT_LIST_HEAD(&ctx->run_list);
INIT_DELAYED_WORK(&ctx->wq, aio_kick_handler);
if (aio_setup_ring(ctx) < 0)
goto out_freectx;
/* limit the number of system wide aios */
spin_lock(&aio_nr_lock);
if (aio_nr + nr_events > aio_max_nr ||
aio_nr + nr_events < aio_nr) {
spin_unlock(&aio_nr_lock);
goto out_cleanup;
}
aio_nr += ctx->max_reqs;
spin_unlock(&aio_nr_lock);
/* now link into global list. */
spin_lock(&mm->ioctx_lock);
hlist_add_head_rcu(&ctx->list, &mm->ioctx_list);
spin_unlock(&mm->ioctx_lock);
dprintk("aio: allocated ioctx %p[%ld]: mm=%p mask=0x%x\n",
ctx, ctx->user_id, current->mm, ctx->ring_info.nr);
return ctx;
out_cleanup:
err = -EAGAIN;
aio_free_ring(ctx);
out_freectx:
mmdrop(mm);
kmem_cache_free(kioctx_cachep, ctx);
dprintk("aio: error allocating ioctx %d\n", err);
return ERR_PTR(err);
}
/* kill_ctx
* Cancels all outstanding aio requests on an aio context. Used
* when the processes owning a context have all exited to encourage
* the rapid destruction of the kioctx.
*/
static void kill_ctx(struct kioctx *ctx)
{
int (*cancel)(struct kiocb *, struct io_event *);
struct task_struct *tsk = current;
DECLARE_WAITQUEUE(wait, tsk);
struct io_event res;
spin_lock_irq(&ctx->ctx_lock);
ctx->dead = 1;
while (!list_empty(&ctx->active_reqs)) {
struct list_head *pos = ctx->active_reqs.next;
struct kiocb *iocb = list_kiocb(pos);
list_del_init(&iocb->ki_list);
cancel = iocb->ki_cancel;
kiocbSetCancelled(iocb);
if (cancel) {
iocb->ki_users++;
spin_unlock_irq(&ctx->ctx_lock);
cancel(iocb, &res);
spin_lock_irq(&ctx->ctx_lock);
}
}
if (!ctx->reqs_active)
goto out;
add_wait_queue(&ctx->wait, &wait);
set_task_state(tsk, TASK_UNINTERRUPTIBLE);
while (ctx->reqs_active) {
spin_unlock_irq(&ctx->ctx_lock);
io_schedule();
set_task_state(tsk, TASK_UNINTERRUPTIBLE);
spin_lock_irq(&ctx->ctx_lock);
}
__set_task_state(tsk, TASK_RUNNING);
remove_wait_queue(&ctx->wait, &wait);
out:
spin_unlock_irq(&ctx->ctx_lock);
}
/* wait_on_sync_kiocb:
* Waits on the given sync kiocb to complete.
*/
ssize_t wait_on_sync_kiocb(struct kiocb *iocb)
{
while (iocb->ki_users) {
set_current_state(TASK_UNINTERRUPTIBLE);
if (!iocb->ki_users)
break;
io_schedule();
}
__set_current_state(TASK_RUNNING);
return iocb->ki_user_data;
}
EXPORT_SYMBOL(wait_on_sync_kiocb);
/* exit_aio: called when the last user of mm goes away. At this point,
* there is no way for any new requests to be submited or any of the
* io_* syscalls to be called on the context. However, there may be
* outstanding requests which hold references to the context; as they
* go away, they will call put_ioctx and release any pinned memory
* associated with the request (held via struct page * references).
*/
void exit_aio(struct mm_struct *mm)
{
struct kioctx *ctx;
while (!hlist_empty(&mm->ioctx_list)) {
ctx = hlist_entry(mm->ioctx_list.first, struct kioctx, list);
hlist_del_rcu(&ctx->list);
kill_ctx(ctx);
if (1 != atomic_read(&ctx->users))
printk(KERN_DEBUG
"exit_aio:ioctx still alive: %d %d %d\n",
atomic_read(&ctx->users), ctx->dead,
ctx->reqs_active);
/*
* We don't need to bother with munmap() here -
* exit_mmap(mm) is coming and it'll unmap everything.
* Since aio_free_ring() uses non-zero ->mmap_size
* as indicator that it needs to unmap the area,
* just set it to 0; aio_free_ring() is the only
* place that uses ->mmap_size, so it's safe.
* That way we get all munmap done to current->mm -
* all other callers have ctx->mm == current->mm.
*/
ctx->ring_info.mmap_size = 0;
put_ioctx(ctx);
}
}
/* aio_get_req
* Allocate a slot for an aio request. Increments the 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->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;
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;
INIT_LIST_HEAD(&req->ki_run_list);
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);
ctx->reqs_active--;
}
if (unlikely(!ctx->reqs_active && ctx->dead))
wake_up_all(&ctx->wait);
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) - 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);
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 inline void really_put_req(struct kioctx *ctx, struct kiocb *req)
{
assert_spin_locked(&ctx->ctx_lock);
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);
ctx->reqs_active--;
if (unlikely(!ctx->reqs_active && ctx->dead))
wake_up_all(&ctx->wait);
}
/* __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=%ld\n",
req, atomic_long_read(&req->ki_filp->f_count));
assert_spin_locked(&ctx->ctx_lock);
req->ki_users--;
BUG_ON(req->ki_users < 0);
if (likely(req->ki_users))
return 0;
list_del(&req->ki_list); /* remove from active_reqs */
req->ki_cancel = NULL;
req->ki_retry = NULL;
fput(req->ki_filp);
req->ki_filp = NULL;
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 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);
return ret;
}
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) {
/*
* RCU protects us against accessing freed memory but
* we have to be careful not to get a reference when the
* reference count already dropped to 0 (ctx->dead test
* is unreliable because of races).
*/
if (ctx->user_id == ctx_id && !ctx->dead && try_get_ioctx(ctx)){
ret = ctx;
break;
}
}
rcu_read_unlock();
return ret;
}
/*
* 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 (!(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.
*/
ret = retry(iocb);
if (ret != -EIOCBRETRY && 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(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);
__aio_put_req(ctx, iocb);
}
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_all_iocbs:
* Process all pending retries queued on the ioctx
* run list, and keep running them until the list
* stays empty.
* Assumes it is operating within the aio issuer's mm context.
*/
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(struct work_struct *work)
{
struct kioctx *ctx = container_of(work, struct kioctx, wq.work);
mm_segment_t oldfs = get_fs();
struct mm_struct *mm;
int requeue;
set_fs(USER_DS);
use_mm(ctx->mm);
spin_lock_irq(&ctx->ctx_lock);
requeue =__aio_run_iocbs(ctx);
mm = ctx->mm;
spin_unlock_irq(&ctx->ctx_lock);
unuse_mm(mm);
set_fs(oldfs);
/*
* we're in a worker thread already; no point using non-zero delay
*/
if (requeue)
queue_delayed_work(aio_wq, &ctx->wq, 0);
}
/*
* 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;
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
* to trigger a retry of the iocb.
* The retry is usually executed by aio workqueue
* threads (See aio_kick_handler).
*/
void 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 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]);
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;
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);
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. */
ret = __aio_put_req(ctx, iocb);
/*
* We have to order our ring_info tail store above and test
* of the wait list below outside the wait lock. This is
* like in wake_up_bit() where clearing a bit has to be
* ordered with the unlocked test.
*/
smp_mb();
if (waitqueue_active(&ctx->wait))
wake_up(&ctx->wait);
spin_unlock_irqrestore(&ctx->ctx_lock, flags);
return ret;
}
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]);
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);
*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);
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)
{
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;
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;
if (unlikely(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 (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)))) {
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:
destroy_timer_on_stack(&to.timer);
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;
int was_dead;
/* delete the entry from the list is someone else hasn't already */
spin_lock(&mm->ioctx_lock);
was_dead = ioctx->dead;
ioctx->dead = 1;
hlist_del_rcu(&ioctx->list);
spin_unlock(&mm->ioctx_lock);
dprintk("aio_release(%p)\n", ioctx);
if (likely(!was_dead))
put_ioctx(ioctx); /* twice for the list */
kill_ctx(ioctx);
/*
* Wake up any waiters. The setting of ctx->dead must be seen
* by other CPUs at this point. Right now, we rely on the
* locking done by the above calls to ensure this consistency.
*/
wake_up_all(&ioctx->wait);
}
/* 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)
io_destroy(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)) {
io_destroy(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;
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))));
/* 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 && ret != -EIOCBRETRY
&& 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:
dprintk("EINVAL: io_submit: 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;
struct file *file;
ssize_t ret;
/* enforce forwards compatibility on users */
if (unlikely(iocb->aio_reserved1 || iocb->aio_reserved2)) {
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, batch); /* returns with 2 references to req */
if (unlikely(!req)) {
fput(file);
return -EAGAIN;
}
req->ki_filp = file;
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)) {
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;
ret = aio_setup_iocb(req, compat);
if (ret)
goto out_put_req;
spin_lock_irq(&ctx->ctx_lock);
/*
* We could have raced with io_destroy() and are currently holding a
* reference to ctx which should be destroyed. We cannot submit IO
* since ctx gets freed as soon as io_submit() puts its reference. The
* check here is reliable: io_destroy() sets ctx->dead before waiting
* for outstanding IO and the barrier between these two is realized by
* unlock of mm->ioctx_lock and lock of ctx->ctx_lock. Analogously we
* increment ctx->reqs_active before checking for ctx->dead and the
* barrier is realized by unlock and lock of ctx->ctx_lock. Thus if we
* don't see ctx->dead set here, io_destroy() waits for our IO to
* finish.
*/
if (ctx->dead) {
spin_unlock_irq(&ctx->ctx_lock);
ret = -EINVAL;
goto out_put_req;
}
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;
}
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: io_submit: 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)
{
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. 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);
}
asmlinkage_protect(5, ret, ctx_id, min_nr, nr, events, timeout);
return ret;
}