From bd3332707bb49a7e4d69ce375cb8d9988e543aad Mon Sep 17 00:00:00 2001
From: Nicholas Mc Guire <der.herr@hofr.at>
Date: Wed, 20 Nov 2013 07:22:09 +0800
Subject: allow preemption in recursive migrate_disable call

Minor cleanup in migrate_disable/migrate_enable. The recursive case
does not need to disable preemption as it is "pinned" to the current
cpu any way so it is safe to preempt it.

Signed-off-by: Nicholas Mc Guire <der.herr@hofr.at>
Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>

diff --git a/kernel/sched/core.c b/kernel/sched/core.c
index b38ae06..fdf5edd 100644
--- a/kernel/sched/core.c
+++ b/kernel/sched/core.c
@@ -2419,13 +2419,12 @@ void migrate_disable(void)
 	WARN_ON_ONCE(p->migrate_disable_atomic);
 #endif
 
-	preempt_disable();
 	if (p->migrate_disable) {
 		p->migrate_disable++;
-		preempt_enable();
 		return;
 	}
 
+	preempt_disable();
 	pin_current_cpu();
 	p->migrate_disable = 1;
 	preempt_enable();
@@ -2451,13 +2450,12 @@ void migrate_enable(void)
 #endif
 	WARN_ON_ONCE(p->migrate_disable <= 0);
 
-	preempt_disable();
 	if (migrate_disable_count(p) > 1) {
 		p->migrate_disable--;
-		preempt_enable();
 		return;
 	}
 
+	preempt_disable();
 	if (unlikely(migrate_disabled_updated(p))) {
 		/*
 		 * See comment in update_migrate_disable() about locking.
-- 
cgit v0.10.2