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.
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;
put_page(info->ring_pages[i]);
if (info->mmap_size) {
- BUG_ON(ctx->mm != current->mm);
vm_munmap(info->mmap_base, info->mmap_size);
}
struct aio_ring *ring;
struct aio_ring_info *info = &ctx->ring_info;
unsigned nr_events = ctx->max_reqs;
+ struct mm_struct *mm = current->mm;
unsigned long size, populate;
int nr_pages;
info->mmap_size = nr_pages * PAGE_SIZE;
dprintk("attempting mmap of %lu bytes\n", info->mmap_size);
- down_write(&ctx->mm->mmap_sem);
+ down_write(&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);
+ up_write(&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,
+ info->nr_pages = get_user_pages(current, mm, info->mmap_base, nr_pages,
1, 0, info->ring_pages, NULL);
- up_write(&ctx->mm->mmap_sem);
+ up_write(&mm->mmap_sem);
if (unlikely(info->nr_pages != nr_pages)) {
aio_free_ring(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);
*/
static struct kioctx *ioctx_alloc(unsigned nr_events)
{
- struct mm_struct *mm;
+ struct mm_struct *mm = current->mm;
struct kioctx *ctx;
int err = -ENOMEM;
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);
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;
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);
+ ctx, ctx->user_id, 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);
* 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);
req->ki_dtor = NULL;
req->private = NULL;
req->ki_iovec = NULL;
- INIT_LIST_HEAD(&req->ki_run_list);
req->ki_eventfd = NULL;
return req;
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
*/
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.
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);
/* 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;
/* 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
+ && ret < 0 && ret != -EIOCBQUEUED
&& iocb->ki_nbytes - iocb->ki_left)
ret = iocb->ki_nbytes - iocb->ki_left;
* don't see ctx->dead set here, io_destroy() waits for our IO to
* finish.
*/
- if (ctx->dead) {
- spin_unlock_irq(&ctx->ctx_lock);
+ if (ctx->dead)
ret = -EINVAL;
+ spin_unlock_irq(&ctx->ctx_lock);
+ if (ret)
goto out_put_req;
+
+ if (unlikely(kiocbIsCancelled(req))) {
+ ret = -EINTR;
+ } else {
+ ret = req->ki_retry(req);
}
- aio_run_iocb(req);
- if (!list_empty(&ctx->run_list)) {
- /* drain the run list */
- while (__aio_run_iocbs(ctx))
- ;
+ 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);
}
- spin_unlock_irq(&ctx->ctx_lock);
aio_put_req(req); /* drop extra ref to req */
return 0;
projects / karo-tx-linux.git / commitdiff