Re: [PATCH v1 1/2] Add polling support to pidfd

On 04/29, Joel Fernandes wrote:

On Mon, Apr 29, 2019 at 10:02:45AM -0400, Joel Fernandes wrote:

quoted

On Sun, Apr 28, 2019 at 06:24:06PM +0200, Oleg Nesterov wrote:

[snip]

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+{
+	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.