diff options
| author | Jens Axboe <axboe@kernel.dk> | 2022-11-20 10:13:44 -0700 |
|---|---|---|
| committer | Jens Axboe <axboe@kernel.dk> | 2022-11-22 06:07:55 -0700 |
| commit | 03e02acda8e267a8183e1e0ed289ff1ef9cd7ed8 (patch) | |
| tree | 757d06e46ed4330edf949425d3036faa8da0ffb0 /include/linux/eventfd.h | |
| parent | caf1aeaffc3b09649a56769e559333ae2c4f1802 (diff) | |
eventfd: provide a eventfd_signal_mask() helper
This is identical to eventfd_signal(), but it allows the caller to pass
in a mask to be used for the poll wakeup key. The use case is avoiding
repeated multishot triggers if we have a dependency between eventfd and
io_uring.
If we setup an eventfd context and register that as the io_uring eventfd,
and at the same time queue a multishot poll request for the eventfd
context, then any CQE posted will repeatedly trigger the multishot request
until it terminates when the CQ ring overflows.
In preparation for io_uring detecting this circular dependency, add the
mentioned helper so that io_uring can pass in EPOLL_URING as part of the
poll wakeup key.
Cc: stable@vger.kernel.org # 6.0
[axboe: fold in !CONFIG_EVENTFD fix from Zhang Qilong]
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Diffstat (limited to 'include/linux/eventfd.h')
| -rw-r--r-- | include/linux/eventfd.h | 7 |
1 files changed, 7 insertions, 0 deletions
diff --git a/include/linux/eventfd.h b/include/linux/eventfd.h index 30eb30d6909b..786824f58d3d 100644 --- a/include/linux/eventfd.h +++ b/include/linux/eventfd.h @@ -40,6 +40,7 @@ struct file *eventfd_fget(int fd); struct eventfd_ctx *eventfd_ctx_fdget(int fd); struct eventfd_ctx *eventfd_ctx_fileget(struct file *file); __u64 eventfd_signal(struct eventfd_ctx *ctx, __u64 n); +__u64 eventfd_signal_mask(struct eventfd_ctx *ctx, __u64 n, unsigned mask); int eventfd_ctx_remove_wait_queue(struct eventfd_ctx *ctx, wait_queue_entry_t *wait, __u64 *cnt); void eventfd_ctx_do_read(struct eventfd_ctx *ctx, __u64 *cnt); @@ -66,6 +67,12 @@ static inline int eventfd_signal(struct eventfd_ctx *ctx, int n) return -ENOSYS; } +static inline int eventfd_signal_mask(struct eventfd_ctx *ctx, __u64 n, + unsigned mask) +{ + return -ENOSYS; +} + static inline void eventfd_ctx_put(struct eventfd_ctx *ctx) { |