summaryrefslogtreecommitdiff
diff options
context:
space:
mode:
authorWen Yang <wenyang.linux@foxmail.com>2023-06-13 20:01:22 +0300
committerChristian Brauner <brauner@kernel.org>2023-06-15 10:22:23 +0300
commit33d8b5d7824c7175ed968b8e89e6db3566e9c177 (patch)
tree9e7c7d027b0c404952478d09c173f1e37f7b8fce
parent5c075c5b8fc4ebc34aac188be4eccc238521eb6f (diff)
downloadlinux-33d8b5d7824c7175ed968b8e89e6db3566e9c177.tar.xz
eventfd: show the EFD_SEMAPHORE flag in fdinfo
The EFD_SEMAPHORE flag should be displayed in fdinfo, as different value could affect the behavior of eventfd. Suggested-by: Christian Brauner <brauner@kernel.org> Signed-off-by: Wen Yang <wenyang.linux@foxmail.com> Cc: Alexander Viro <viro@zeniv.linux.org.uk> Cc: Jens Axboe <axboe@kernel.dk> Cc: Christian Brauner <brauner@kernel.org> Cc: Christoph Hellwig <hch@lst.de> Cc: Dylan Yudaken <dylany@fb.com> Cc: David Woodhouse <dwmw@amazon.co.uk> Cc: Matthew Wilcox <willy@infradead.org> Cc: Eric Biggers <ebiggers@google.com> Cc: linux-fsdevel@vger.kernel.org Cc: linux-kernel@vger.kernel.org Message-Id: <tencent_05B9CFEFE6B9BC2A9B3A27886A122A7D9205@qq.com> Signed-off-by: Christian Brauner <brauner@kernel.org>
-rw-r--r--fs/eventfd.c10
1 files changed, 6 insertions, 4 deletions
diff --git a/fs/eventfd.c b/fs/eventfd.c
index 6c06a527747f..8aa36cd37351 100644
--- a/fs/eventfd.c
+++ b/fs/eventfd.c
@@ -33,10 +33,10 @@ struct eventfd_ctx {
/*
* Every time that a write(2) is performed on an eventfd, the
* value of the __u64 being written is added to "count" and a
- * wakeup is performed on "wqh". A read(2) will return the "count"
- * value to userspace, and will reset "count" to zero. The kernel
- * side eventfd_signal() also, adds to the "count" counter and
- * issue a wakeup.
+ * wakeup is performed on "wqh". If EFD_SEMAPHORE flag was not
+ * specified, a read(2) will return the "count" value to userspace,
+ * and will reset "count" to zero. The kernel side eventfd_signal()
+ * also, adds to the "count" counter and issue a wakeup.
*/
__u64 count;
unsigned int flags;
@@ -301,6 +301,8 @@ static void eventfd_show_fdinfo(struct seq_file *m, struct file *f)
(unsigned long long)ctx->count);
spin_unlock_irq(&ctx->wqh.lock);
seq_printf(m, "eventfd-id: %d\n", ctx->id);
+ seq_printf(m, "eventfd-semaphore: %d\n",
+ !!(ctx->flags & EFD_SEMAPHORE));
}
#endif