From f38550288be61cfecd33a78ebb7cd6474b82e057 Mon Sep 17 00:00:00 2001 From: Dylan Yudaken Date: Thu, 12 May 2022 02:18:34 -0700 Subject: [PATCH] io_uring: only wake when the correct events are set [ Upstream commit 1b1d7b4bf1d9948c8dba5ee550459ce7c65ac019 ] The check for waking up a request compares the poll_t bits, however this will always contain some common flags so this always wakes up. For files with single wait queues such as sockets this can cause the request to be sent to the async worker unnecesarily. Further if it is non-blocking will complete the request with EAGAIN which is not desired. Here exclude these common events, making sure to not exclude POLLERR which might be important. Fixes: d7718a9d25a6 ("io_uring: use poll driven retry for files that support it") Signed-off-by: Dylan Yudaken Link: https://lore.kernel.org/r/20220512091834.728610-3-dylany@fb.com Signed-off-by: Jens Axboe Signed-off-by: Sasha Levin --- fs/io_uring.c | 5 +++-- 1 file changed, 3 insertions(+), 2 deletions(-) diff --git a/fs/io_uring.c b/fs/io_uring.c index 25b0832e0fc39..0bd592af1bf7d 100644 --- a/fs/io_uring.c +++ b/fs/io_uring.c @@ -5634,6 +5634,7 @@ static void io_poll_cancel_req(struct io_kiocb *req) #define wqe_to_req(wait) ((void *)((unsigned long) (wait)->private & ~1)) #define wqe_is_double(wait) ((unsigned long) (wait)->private & 1) +#define IO_ASYNC_POLL_COMMON (EPOLLONESHOT | POLLPRI) static int io_poll_wake(struct wait_queue_entry *wait, unsigned mode, int sync, void *key) @@ -5668,7 +5669,7 @@ static int io_poll_wake(struct wait_queue_entry *wait, unsigned mode, int sync, } /* for instances that support it check for an event match first */ - if (mask && !(mask & poll->events)) + if (mask && !(mask & (poll->events & ~IO_ASYNC_POLL_COMMON))) return 0; if (io_poll_get_ownership(req)) { @@ -5824,7 +5825,7 @@ static int io_arm_poll_handler(struct io_kiocb *req) struct io_ring_ctx *ctx = req->ctx; struct async_poll *apoll; struct io_poll_table ipt; - __poll_t mask = EPOLLONESHOT | POLLERR | POLLPRI; + __poll_t mask = IO_ASYNC_POLL_COMMON | POLLERR; int ret; if (!def->pollin && !def->pollout)