Commit aacf2f9f authored by Pavel Begunkov's avatar Pavel Begunkov Committed by Jens Axboe
Browse files

io_uring: fix req->apoll_events 



apoll_events should be set once in the beginning of poll arming just as
poll->events and not change after. However, currently io_uring resets it
on each __io_poll_execute() for no clear reason. There is also a place
in __io_arm_poll_handler() where we add EPOLLONESHOT to downgrade a
multishot, but forget to do the same thing with ->apoll_events, which is
buggy.

Fixes: 81459350 ("io_uring: cache req->apoll->events in req->cflags")
Signed-off-by: default avatarPavel Begunkov <asml.silence@gmail.com>
Reviewed-by: default avatarHao Xu <howeyxu@tencent.com>
Link: https://lore.kernel.org/r/0aef40399ba75b1a4d2c2e85e6e8fd93c02fc6e4.1655814213.git.asml.silence@gmail.com


Signed-off-by: default avatarJens Axboe <axboe@kernel.dk>
parent b60cac14

fs/io_uring.c

+8 −4
Original line number Diff line number Diff line
@@ -6950,7 +6950,8 @@ static void io_apoll_task_func(struct io_kiocb *req, bool *locked) 
		io_req_complete_failed(req, ret);

}



static void __io_poll_execute(struct io_kiocb *req, int mask, __poll_t events)

static void __io_poll_execute(struct io_kiocb *req, int mask,

			      __poll_t __maybe_unused events)

{

	req->cqe.res = mask;

	/*
@@ -6959,7 +6960,6 @@ static void __io_poll_execute(struct io_kiocb *req, int mask, __poll_t events) 
	 * CPU. We want to avoid pulling in req->apoll->events for that

	 * case.

	 */

	req->apoll_events = events;

	if (req->opcode == IORING_OP_POLL_ADD)

		req->io_task_work.func = io_poll_task_func;

	else
@@ -7110,6 +7110,8 @@ static int __io_arm_poll_handler(struct io_kiocb *req, 
	io_init_poll_iocb(poll, mask, io_poll_wake);

	poll->file = req->file;



	req->apoll_events = poll->events;



	ipt->pt._key = mask;

	ipt->req = req;

	ipt->error = 0;
@@ -7140,8 +7142,10 @@ static int __io_arm_poll_handler(struct io_kiocb *req, 


	if (mask) {

		/* can't multishot if failed, just queue the event we've got */

		if (unlikely(ipt->error || !ipt->nr_entries))

		if (unlikely(ipt->error || !ipt->nr_entries)) {

			poll->events |= EPOLLONESHOT;

			req->apoll_events |= EPOLLONESHOT;

		}

		__io_poll_execute(req, mask, poll->events);

		return 0;

	}
@@ -7388,7 +7392,7 @@ static int io_poll_add_prep(struct io_kiocb *req, const struct io_uring_sqe *sqe 
		return -EINVAL;



	io_req_set_refcount(req);

	req->apoll_events = poll->events = io_poll_parse_events(sqe, flags);

	poll->events = io_poll_parse_events(sqe, flags);

	return 0;

}