From 17cf22c33e1f1b5e435469c84e43872579497653 Mon Sep 17 00:00:00 2001
From: "Eric W. Biederman" <ebiederm@xmission.com>
Date: Tue, 2 Mar 2010 14:51:53 -0800
Subject: pidns: Use task_active_pid_ns where appropriate

The expressions tsk->nsproxy->pid_ns and task_active_pid_ns
aka ns_of_pid(task_pid(tsk)) should have the same number of
cache line misses with the practical difference that
ns_of_pid(task_pid(tsk)) is released later in a processes life.

Furthermore by using task_active_pid_ns it becomes trivial
to write an unshare implementation for the the pid namespace.

So I have used task_active_pid_ns everywhere I can.

In fork since the pid has not yet been attached to the
process I use ns_of_pid, to achieve the same effect.

Signed-off-by: Eric W. Biederman <ebiederm@xmission.com>
---
 kernel/events/core.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

(limited to 'kernel/events')

diff --git a/kernel/events/core.c b/kernel/events/core.c
index dbccf83c134d..738f3564e83b 100644
--- a/kernel/events/core.c
+++ b/kernel/events/core.c
@@ -6155,7 +6155,7 @@ perf_event_alloc(struct perf_event_attr *attr, int cpu,
 
 	event->parent		= parent_event;
 
-	event->ns		= get_pid_ns(current->nsproxy->pid_ns);
+	event->ns		= get_pid_ns(task_active_pid_ns(current));
 	event->id		= atomic64_inc_return(&perf_event_id);
 
 	event->state		= PERF_EVENT_STATE_INACTIVE;
-- 
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