io_uring: improve same wq polling
Move earlier the check for whether __io_queue_proc() tries to poll
already polled waitqueue, and do the same for the second poll entry, if
any. Shouldn't really matter, but at least it would have a more
predictable behaviour.
Signed-off-by: Pavel Begunkov <asml.silence@gmail.com>
Link: https://lore.kernel.org/r/8cb428cfe8ade0fd055859fabb878db8777d4c2f.1629228203.git.asml.silence@gmail.com
Signed-off-by: Jens Axboe <axboe@kernel.dk>
diff --git a/fs/io_uring.c b/fs/io_uring.c
index 6f2668b..71d5484 100644
--- a/fs/io_uring.c
+++ b/fs/io_uring.c
@@ -5062,8 +5062,13 @@ static void __io_queue_proc(struct io_poll_iocb *poll, struct io_poll_table *pt,
if (unlikely(pt->nr_entries)) {
struct io_poll_iocb *poll_one = poll;
+ /* double add on the same waitqueue head, ignore */
+ if (poll_one->head == head)
+ return;
/* already have a 2nd entry, fail a third attempt */
if (*poll_ptr) {
+ if ((*poll_ptr)->head == head)
+ return;
pt->error = -EINVAL;
return;
}
@@ -5073,9 +5078,6 @@ static void __io_queue_proc(struct io_poll_iocb *poll, struct io_poll_table *pt,
*/
if (!(poll_one->events & EPOLLONESHOT))
poll_one->events |= EPOLLONESHOT;
- /* double add on the same waitqueue head, ignore */
- if (poll_one->head == head)
- return;
poll = kmalloc(sizeof(*poll), GFP_ATOMIC);
if (!poll) {
pt->error = -ENOMEM;