diff options
author | Jens Axboe <axboe@kernel.dk> | 2022-11-20 10:10:53 -0700 |
---|---|---|
committer | Jens Axboe <axboe@kernel.dk> | 2022-11-21 07:45:29 -0700 |
commit | caf1aeaffc3b09649a56769e559333ae2c4f1802 (patch) | |
tree | 2ff10e07dda0aa001af69621e5b9dbb3b26cc1e9 /include/uapi/linux/eventpoll.h | |
parent | f9d567c75ec216447f36da6e855500023504fa04 (diff) |
eventpoll: add EPOLL_URING_WAKE poll wakeup flag
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>
Diffstat (limited to 'include/uapi/linux/eventpoll.h')
-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)) |