author: Al Viro <viro@zeniv.linux.org.uk> 2019-03-07 21:45:41 -0500
committer: Al Viro <viro@zeniv.linux.org.uk> 2019-03-17 20:52:28 -0400
commit: af5c72b1fc7a00aa484e90b0c4e0eeb582545634
parent: 2bb874c0d873d13bd9b9b9c6d7b7c4edab18c8b4
Commit Summary:
Diffstat:
1 file changed, 39 insertions, 47 deletions
diff --git a/fs/aio.c b/fs/aio.c
index f405e2fd8e28..39a075992ca2 100644
--- a/fs/aio.c
+++ b/fs/aio.c
@@ -181,7 +181,7 @@ struct poll_iocb {
struct file *file;
struct wait_queue_head *head;
__poll_t events;
- bool woken;
+ bool done;
bool cancelled;
struct wait_queue_entry wait;
struct work_struct work;
@@ -1606,12 +1606,6 @@ static int aio_fsync(struct fsync_iocb *req, const struct iocb *iocb,
return 0;
}
-static inline void aio_poll_complete(struct aio_kiocb *iocb, __poll_t mask)
-{
- iocb->ki_res.res = mangle_poll(mask);
- iocb_put(iocb);
-}
-
static void aio_poll_complete_work(struct work_struct *work)
{
struct poll_iocb *req = container_of(work, struct poll_iocb, work);
@@ -1637,9 +1631,11 @@ static void aio_poll_complete_work(struct work_struct *work)
return;
}
list_del_init(&iocb->ki_list);
+ iocb->ki_res.res = mangle_poll(mask);
+ req->done = true;
spin_unlock_irq(&ctx->ctx_lock);
- aio_poll_complete(iocb, mask);
+ iocb_put(iocb);
}
/* assumes we are called with irqs disabled */
@@ -1667,31 +1663,27 @@ static int aio_poll_wake(struct wait_queue_entry *wait, unsigned mode, int sync,
__poll_t mask = key_to_poll(key);
unsigned long flags;
- req->woken = true;
-
/* for instances that support it check for an event match first: */
- if (mask) {
- if (!(mask & req->events))
- return 0;
+ if (mask && !(mask & req->events))
+ return 0;
+ list_del_init(&req->wait.entry);
+
+ if (mask && spin_trylock_irqsave(&iocb->ki_ctx->ctx_lock, flags)) {
/*
* Try to complete the iocb inline if we can. Use
* irqsave/irqrestore because not all filesystems (e.g. fuse)
* call this function with IRQs disabled and because IRQs
* have to be disabled before ctx_lock is obtained.
*/
- if (spin_trylock_irqsave(&iocb->ki_ctx->ctx_lock, flags)) {
- list_del(&iocb->ki_list);
- spin_unlock_irqrestore(&iocb->ki_ctx->ctx_lock, flags);
-
- list_del_init(&req->wait.entry);
- aio_poll_complete(iocb, mask);
- return 1;
- }
+ list_del(&iocb->ki_list);
+ iocb->ki_res.res = mangle_poll(mask);
+ req->done = true;
+ spin_unlock_irqrestore(&iocb->ki_ctx->ctx_lock, flags);
+ iocb_put(iocb);
+ } else {
+ schedule_work(&req->work);
}
-
- list_del_init(&req->wait.entry);
- schedule_work(&req->work);
return 1;
}
@@ -1723,6 +1715,7 @@ static ssize_t aio_poll(struct aio_kiocb *aiocb, const struct iocb *iocb)
struct kioctx *ctx = aiocb->ki_ctx;
struct poll_iocb *req = &aiocb->poll;
struct aio_poll_table apt;
+ bool cancel = false;
__poll_t mask;
/* reject any unknown events outside the normal event mask. */
@@ -1736,7 +1729,7 @@ static ssize_t aio_poll(struct aio_kiocb *aiocb, const struct iocb *iocb)
req->events = demangle_poll(iocb->aio_buf) | EPOLLERR | EPOLLHUP;
req->head = NULL;
- req->woken = false;
+ req->done = false;
req->cancelled = false;
apt.pt._qproc = aio_poll_queue_proc;
@@ -1749,36 +1742,33 @@ static ssize_t aio_poll(struct aio_kiocb *aiocb, const struct iocb *iocb)
init_waitqueue_func_entry(&req->wait, aio_poll_wake);
mask = vfs_poll(req->file, &apt.pt) & req->events;
- if (unlikely(!req->head)) {
- /* we did not manage to set up a waitqueue, done */
- goto out;
- }
-
spin_lock_irq(&ctx->ctx_lock);
- spin_lock(&req->head->lock);
- if (req->woken) {
- /* wake_up context handles the rest */
- mask = 0;
+ if (likely(req->head)) {
+ spin_lock(&req->head->lock);
+ if (unlikely(list_empty(&req->wait.entry))) {
+ if (apt.error)
+ cancel = true;
+ apt.error = 0;
+ mask = 0;
+ }
+ if (mask || apt.error) {
+ list_del_init(&req->wait.entry);
+ } else if (cancel) {
+ WRITE_ONCE(req->cancelled, true);
+ } else if (!req->done) { /* actually waiting for an event */
+ list_add_tail(&aiocb->ki_list, &ctx->active_reqs);
+ aiocb->ki_cancel = aio_poll_cancel;
+ }
+ spin_unlock(&req->head->lock);
+ }
+ if (mask) { /* no async, we'd stolen it */
+ aiocb->ki_res.res = mangle_poll(mask);
apt.error = 0;
- } else if (mask || apt.error) {
- /* if we get an error or a mask we are done */
- WARN_ON_ONCE(list_empty(&req->wait.entry));
- list_del_init(&req->wait.entry);
- } else {
- /* actually waiting for an event */
- list_add_tail(&aiocb->ki_list, &ctx->active_reqs);
- aiocb->ki_cancel = aio_poll_cancel;
}
- spin_unlock(&req->head->lock);
spin_unlock_irq(&ctx->ctx_lock);
-
-out:
- if (unlikely(apt.error))
- return apt.error;
-
if (mask)
- aio_poll_complete(aiocb, mask);
- return 0;
+ iocb_put(aiocb);
+ return apt.error;
}
static int __io_submit_one(struct kioctx *ctx, const struct iocb *iocb,