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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 /fs/eventpoll.c | |
| 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 'fs/eventpoll.c')
| -rw-r--r-- | fs/eventpoll.c | 18 |
1 files changed, 10 insertions, 8 deletions
diff --git a/fs/eventpoll.c b/fs/eventpoll.c index 2f1f05315709..13d4c3d50412 100644 --- a/fs/eventpoll.c +++ b/fs/eventpoll.c @@ -548,7 +548,8 @@ out_unlock: */ #ifdef CONFIG_DEBUG_LOCK_ALLOC -static void ep_poll_safewake(struct eventpoll *ep, struct epitem *epi) +static void ep_poll_safewake(struct eventpoll *ep, struct epitem *epi, + unsigned pollflags) { struct eventpoll *ep_src; unsigned long flags; @@ -579,16 +580,17 @@ static void ep_poll_safewake(struct eventpoll *ep, struct epitem *epi) } spin_lock_irqsave_nested(&ep->poll_wait.lock, flags, nests); ep->nests = nests + 1; - wake_up_locked_poll(&ep->poll_wait, EPOLLIN); + wake_up_locked_poll(&ep->poll_wait, EPOLLIN | pollflags); ep->nests = 0; spin_unlock_irqrestore(&ep->poll_wait.lock, flags); } #else -static void ep_poll_safewake(struct eventpoll *ep, struct epitem *epi) +static void ep_poll_safewake(struct eventpoll *ep, struct epitem *epi, + unsigned pollflags) { - wake_up_poll(&ep->poll_wait, EPOLLIN); + wake_up_poll(&ep->poll_wait, EPOLLIN | pollflags); } #endif @@ -815,7 +817,7 @@ static void ep_free(struct eventpoll *ep) /* We need to release all tasks waiting for these file */ if (waitqueue_active(&ep->poll_wait)) - ep_poll_safewake(ep, NULL); + ep_poll_safewake(ep, NULL, 0); /* * We need to lock this because we could be hit by @@ -1284,7 +1286,7 @@ out_unlock: /* We have to call this outside the lock */ if (pwake) - ep_poll_safewake(ep, epi); + ep_poll_safewake(ep, epi, pollflags & EPOLL_URING_WAKE); if (!(epi->event.events & EPOLLEXCLUSIVE)) ewake = 1; @@ -1589,7 +1591,7 @@ static int ep_insert(struct eventpoll *ep, const struct epoll_event *event, /* We have to call this outside the lock */ if (pwake) - ep_poll_safewake(ep, NULL); + ep_poll_safewake(ep, NULL, 0); return 0; @@ -1692,7 +1694,7 @@ static int ep_modify(struct eventpoll *ep, struct epitem *epi, /* We have to call this outside the lock */ if (pwake) - ep_poll_safewake(ep, NULL); + ep_poll_safewake(ep, NULL, 0); return 0; } |