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From: Oleg Nesterov <oleg@redhat.com>
To: Christian Brauner <christian.brauner@ubuntu.com>
Cc: linux-kernel@vger.kernel.org,
	Christian Brauner <christian@brauner.io>,
	"Peter Zijlstra (Intel)" <peterz@infradead.org>,
	Ingo Molnar <mingo@kernel.org>,
	Thomas Gleixner <tglx@linutronix.de>,
	"Eric W. Biederman" <ebiederm@xmission.com>,
	Kees Cook <keescook@chromium.org>,
	Sargun Dhillon <sargun@sargun.me>,
	Aleksa Sarai <cyphar@cyphar.com>,
	linux-kselftest@vger.kernel.org,
	Josh Triplett <josh@joshtriplett.org>,
	Jens Axboe <axboe@kernel.dk>,
	linux-api@vger.kernel.org, Jann Horn <jannh@google.com>
Subject: Re: [PATCH v2 2/4] exit: support non-blocking pidfds
Date: Thu, 3 Sep 2020 16:22:42 +0200	[thread overview]
Message-ID: <20200903142241.GI4386@redhat.com> (raw)
In-Reply-To: <20200902102130.147672-3-christian.brauner@ubuntu.com>

On 09/02, Christian Brauner wrote:
>
> It also makes the API more consistent and uniform. In essence, waitid() is
> treated like a read on a non-blocking pidfd or a recvmsg() on a non-blocking
> socket.
> With the addition of support for non-blocking pidfds we support the same
> functionality that sockets do. For sockets() recvmsg() supports MSG_DONTWAIT
> for pidfds waitid() supports WNOHANG.

What I personally do not like is that waitid(WNOHANG) returns zero or EAGAIN
depending on f_flags & O_NONBLOCK... This doesn't match recvmsg(MSG_DONTWAIT)
and doesn't look consistent to me.

Nevermind, the patch looks correct and if you think this can really help
user-space I won't argue.

Reviewed-by: Oleg Nesterov <oleg@redhat.com>


  reply	other threads:[~2020-09-03 14:48 UTC|newest]

Thread overview: 16+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2020-09-02 10:21 [PATCH v2 0/4] Support non-blocking pidfds Christian Brauner
2020-09-02 10:21 ` [PATCH v2 1/4] pidfd: support PIDFD_NONBLOCK in pidfd_open() Christian Brauner
2020-09-03 14:31   ` Oleg Nesterov
2020-09-03 14:58   ` Oleg Nesterov
2020-09-03 15:25     ` Christian Brauner
2020-09-03 23:50   ` Josh Triplett
2020-09-02 10:21 ` [PATCH v2 2/4] exit: support non-blocking pidfds Christian Brauner
2020-09-03 14:22   ` Oleg Nesterov [this message]
2020-09-03 15:38     ` Christian Brauner
2020-09-03 23:54       ` Josh Triplett
2020-09-03 23:56   ` Josh Triplett
2020-09-04 10:29     ` Christian Brauner
2020-09-02 10:21 ` [PATCH v2 3/4] tests: port pidfd_wait to kselftest harness Christian Brauner
2020-09-02 10:21 ` [PATCH v2 4/4] tests: add waitid() tests for non-blocking pidfds Christian Brauner
2020-09-03 23:58 ` [PATCH v2 0/4] Support " Josh Triplett
2020-09-04 10:30   ` Christian Brauner

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