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io_uring: don't race double poll setting REQ_F_ASYNC_DATA

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Just as with io_poll_double_prepare() setting REQ_F_DOUBLE_POLL, we can
race with the first poll entry when setting REQ_F_ASYNC_DATA. Move it
under io_poll_double_prepare().

Fixes: a18427bb2d9b ("io_uring: optimise submission side poll_refs")
Signed-off-by: Pavel Begunkov <asml.silence@gmail.com>
Link: https://lore.kernel.org/r/df6920f509c11115aa2bce8b34dc5fdb0eb98920.1657203020.git.asml.silence@gmail.com
Signed-off-by: Jens Axboe <axboe@kernel.dk>
This commit is contained in:
Pavel Begunkov 2022-07-07 15:13:15 +01:00 committed by Jens Axboe
parent 7a121ced6e
commit ceff501790
1 changed files with 3 additions and 3 deletions
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6
io_uring/poll.c
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@ -410,6 +410,8 @@ static void io_poll_double_prepare(struct io_kiocb *req)
spin_lock_irq(&head->lock);
req->flags |= REQ_F_DOUBLE_POLL;
if (req->opcode == IORING_OP_POLL_ADD)
req->flags |= REQ_F_ASYNC_DATA;
if (head)
spin_unlock_irq(&head->lock);
@ -448,13 +450,11 @@ static void __io_queue_proc(struct io_poll *poll, struct io_poll_table *pt,
return;
}
io_poll_double_prepare(req);
/* mark as double wq entry */
wqe_private |= IO_WQE_F_DOUBLE;
io_init_poll_iocb(poll, first->events, first->wait.func);
io_poll_double_prepare(req);
*poll_ptr = poll;
if (req->opcode == IORING_OP_POLL_ADD)
req->flags |= REQ_F_ASYNC_DATA;
} else {
/* fine to modify, there is no poll queued to race with us */
req->flags |= REQ_F_SINGLE_POLL;