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author | Jens Axboe <axboe@kernel.dk> | 2022-11-20 10:10:53 -0700 |
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committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2023-01-04 11:28:47 +0100 |
commit | 717ed90a661494b895609fc536382dec40f71de6 (patch) | |
tree | 991f00d56072323b401a0d8113d8383ef24cbaa2 /include/uapi | |
parent | d6a980a0da6cacb523bb1e069b1780ae1c3086a7 (diff) | |
download | linux-717ed90a661494b895609fc536382dec40f71de6.tar.gz |
eventpoll: add EPOLL_URING_WAKE poll wakeup flag
[ Upstream commit caf1aeaffc3b09649a56769e559333ae2c4f1802 ] We can have dependencies between epoll and io_uring. Consider an epoll context, identified by the epfd file descriptor, and an io_uring file descriptor identified by iofd. If we add iofd to the epfd context, and arm a multishot poll request for epfd with iofd, then the multishot poll request will repeatedly trigger and generate events until terminated by CQ ring overflow. This isn't a desired behavior. Add EPOLL_URING so that io_uring can pass it in as part of the poll wakeup key, and io_uring can check for that to detect a potential recursive invocation. Cc: stable@vger.kernel.org # 6.0 Signed-off-by: Jens Axboe <axboe@kernel.dk> Stable-dep-of: 4464853277d0 ("io_uring: pass in EPOLL_URING_WAKE for eventfd signaling and wakeups") Signed-off-by: Sasha Levin <sashal@kernel.org>
Diffstat (limited to 'include/uapi')
-rw-r--r-- | include/uapi/linux/eventpoll.h | 6 |
1 files changed, 6 insertions, 0 deletions
diff --git a/include/uapi/linux/eventpoll.h b/include/uapi/linux/eventpoll.h index 8a3432d0f0dc..e687658843b1 100644 --- a/include/uapi/linux/eventpoll.h +++ b/include/uapi/linux/eventpoll.h @@ -41,6 +41,12 @@ #define EPOLLMSG (__force __poll_t)0x00000400 #define EPOLLRDHUP (__force __poll_t)0x00002000 +/* + * Internal flag - wakeup generated by io_uring, used to detect recursion back + * into the io_uring poll handler. + */ +#define EPOLL_URING_WAKE ((__force __poll_t)(1U << 27)) + /* Set exclusive wakeup mode for the target file descriptor */ #define EPOLLEXCLUSIVE ((__force __poll_t)(1U << 28)) |