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authorJens Axboe <axboe@kernel.dk>2022-11-20 20:13:44 +0300
committerJens Axboe <axboe@kernel.dk>2022-11-22 16:07:55 +0300
commit03e02acda8e267a8183e1e0ed289ff1ef9cd7ed8 (patch)
tree757d06e46ed4330edf949425d3036faa8da0ffb0 /include/linux/eventfd.h
parentcaf1aeaffc3b09649a56769e559333ae2c4f1802 (diff)
downloadlinux-03e02acda8e267a8183e1e0ed289ff1ef9cd7ed8.tar.xz
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.h7
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)
{