| Message ID | tencent_59C3AA88A8F1829226E5D3619837FC4A9E09@qq.com (mailing list archive) |
|---|---|
| State | Superseded |
| Headers | show |
| Series | eventfd: show flags in fdinfo | expand |
On Mon, Jun 12, 2023 at 02:59:47AM +0800, wenyang.linux@foxmail.com wrote: > From: Wen Yang <wenyang.linux@foxmail.com> > > The flags should be displayed in fdinfo, as different flags > could affect the behavior of eventfd. > > 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 > --- > fs/eventfd.c | 9 +++++---- > 1 file changed, 5 insertions(+), 4 deletions(-) > > diff --git a/fs/eventfd.c b/fs/eventfd.c > index 6c06a527747f..5b5448e65f6f 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 +301,7 @@ 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-flags: 0%o\n", ctx->flags); EFD_CLOEXEC and EFD_NONBLOCK are mapped to generic O_* flags and are included in fdinfo output already: pos: 0 flags: 02000002 -> O_CLOEXEC/EFD_CLOEXEC | O_RDWR mnt_id: 15 ino: 12497 eventfd-count: 0 eventfd-id: 156 So the only thing you really care about is EFD_SEMAPHORE. Since this changes the type of the eventfd I would just do either: eventfd-semaphore: {0,1} or - if we can reasonably expect a third type: eventfd-type: {0, ..., n} though I suspect since it hasn't changed since 2.6-something that eventfd-semaphore: {0,1} is probably fine. so you only really care about EFD_SEMAPHORE.
diff --git a/fs/eventfd.c b/fs/eventfd.c index 6c06a527747f..5b5448e65f6f 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 +301,7 @@ 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-flags: 0%o\n", ctx->flags); } #endif