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| author | Jens Axboe <axboe@kernel.dk> | 2022-11-20 20:10:53 +0300 |
|---|---|---|
| committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2023-01-04 13:39:24 +0300 |
| commit | 2f093775022b45253b0d8df0e7296e7bc0d13a7b (patch) | |
| tree | 0bc9699789d4d8f8ac9b3f3c8fee239516b5db0f /include/uapi | |
| parent | b76c5373f084c802964e751efb825934a9bbbbec (diff) | |
| download | linux-2f093775022b45253b0d8df0e7296e7bc0d13a7b.tar.xz | |
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>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.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)) |