From: Pavel Begunkov asml.silence@gmail.com
[ Upstream commit aacf2f9f382c91df73f33317e28a4c34c8038986 ]
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: 81459350d581e ("io_uring: cache req->apoll->events in req->cflags") Signed-off-by: Pavel Begunkov asml.silence@gmail.com Reviewed-by: Hao Xu howeyxu@tencent.com Link: https://lore.kernel.org/r/0aef40399ba75b1a4d2c2e85e6e8fd93c02fc6e4.165581421... Signed-off-by: Jens Axboe axboe@kernel.dk Signed-off-by: Sasha Levin sashal@kernel.org --- fs/io_uring.c | 12 ++++++++---- 1 file changed, 8 insertions(+), 4 deletions(-)
diff --git a/fs/io_uring.c b/fs/io_uring.c index 1070d22a1c2b..38ecea726254 100644 --- a/fs/io_uring.c +++ b/fs/io_uring.c @@ -5984,7 +5984,8 @@ 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->result = mask; /* @@ -5993,7 +5994,6 @@ 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 @@ -6143,6 +6143,8 @@ 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; @@ -6173,8 +6175,10 @@ 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; } @@ -6387,7 +6391,7 @@ 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; }