From: Oleg Nesterov <oleg@redhat.com>
To: Joel Fernandes <joel@joelfernandes.org>
Cc: Christian Brauner <christian@brauner.io>,
linux-kernel@vger.kernel.org, luto@amacapital.net,
rostedt@goodmis.org, dancol@google.com, sspatil@google.com,
jannh@google.com, surenb@google.com, timmurray@google.com,
Jonathan Kowalski <bl0pbl33p@gmail.com>,
torvalds@linux-foundation.org, kernel-team@android.com,
Andrew Morton <akpm@linux-foundation.org>,
Arnd Bergmann <arnd@arndb.de>,
"Eric W. Biederman" <ebiederm@xmission.com>,
Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
Ingo Molnar <mingo@kernel.org>, Jann Horn <jann@thejh.net>,
linux-kselftest@vger.kernel.org, Michal Hocko <mhocko@suse.com>,
"Peter Zijlstra (Intel)" <peterz@infradead.org>,
Serge Hallyn <serge@hallyn.com>, Shuah Khan <shuah@kernel.org>,
Stephen Rothwell <sfr@canb.auug.org.au>, Thomas Gleixner <tgl>
Subject: Re: [PATCH v1 1/2] Add polling support to pidfd
Date: Mon, 29 Apr 2019 16:25:55 +0200 [thread overview]
Message-ID: <20190429142555.GB17715@redhat.com> (raw)
In-Reply-To: <20190429140743.GB173743@google.com>
On 04/29, Joel Fernandes wrote:
>
> On Mon, Apr 29, 2019 at 10:02:45AM -0400, Joel Fernandes wrote:
> > On Sun, Apr 28, 2019 at 06:24:06PM +0200, Oleg Nesterov wrote:
> [snip]
> > > > > +{
> > > > > + struct pid *pid;
> > > > > +
> > > > > + lockdep_assert_held(&tasklist_lock);
> > > > > +
> > > > > + pid = get_task_pid(task, PIDTYPE_PID);
> > > > > + wake_up_all(&pid->wait_pidfd);
> > > > > + put_pid(pid);
> > >
> > > Why get/put?
> >
> > Yes, pid_task() should do it. Will update it. Thanks!
>
> I spoke too soon. We need the task's pid of type PIDTYPE_PID. How else can we
> get it? This does an atomic_inc on the pid->count, so we need to put_pid()
> after we are done with it. Did I miss something?
Just use task_pid(task);
Oleg.
next prev parent reply other threads:[~2019-04-29 14:25 UTC|newest]
Thread overview: 13+ messages / expand[flat|nested] mbox.gz Atom feed top
[not found] <20190425190010.46489-1-joel@joelfernandes.org>
2019-04-25 22:24 ` [PATCH v1 1/2] Add polling support to pidfd Christian Brauner
2019-04-26 14:23 ` Joel Fernandes
2019-04-26 15:21 ` Christian Brauner
2019-04-26 15:31 ` Christian Brauner
2019-04-28 16:24 ` Oleg Nesterov
2019-04-29 14:02 ` Joel Fernandes
2019-04-29 14:07 ` Joel Fernandes
2019-04-29 14:25 ` Oleg Nesterov [this message]
2019-04-29 14:20 ` Oleg Nesterov
2019-04-29 16:32 ` Joel Fernandes
2019-04-30 11:53 ` Oleg Nesterov
2019-04-30 12:07 ` Oleg Nesterov
2019-04-30 15:49 ` Joel Fernandes
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