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| author | Wen Yang <wenyang.linux@foxmail.com> | 2023-06-14 01:01:22 +0800 |
|---|---|---|
| committer | Christian Brauner <brauner@kernel.org> | 2023-06-15 09:22:23 +0200 |
| commit | 33d8b5d7824c7175ed968b8e89e6db3566e9c177 (patch) | |
| tree | 9e7c7d027b0c404952478d09c173f1e37f7b8fce /fs/eventfd.c | |
| parent | 5c075c5b8fc4ebc34aac188be4eccc238521eb6f (diff) | |
| download | lwn-33d8b5d7824c7175ed968b8e89e6db3566e9c177.tar.gz lwn-33d8b5d7824c7175ed968b8e89e6db3566e9c177.zip | |
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>
Diffstat (limited to 'fs/eventfd.c')
| -rw-r--r-- | fs/eventfd.c | 10 |
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 |