sched: Adjust p->sched_reset_on_fork when nothing else changes

If the policy and priority remain unchanged a possible modification of
p->sched_reset_on_fork gets lost in the early exit path.

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
[ Rebase ontop of v3.14-rc1. ]
Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
Signed-off-by: Peter Zijlstra <peterz@infradead.org>
Link: http://lkml.kernel.org/r/1391803122-4425-5-git-send-email-bigeasy@linutronix.de
Signed-off-by: Ingo Molnar <mingo@kernel.org>

kernel/sched/core.c

@@ -3362,7 +3362,8 @@ recheck:
 	}
 
 	/*
-	 * If not changing anything there's no need to proceed further:
+	 * If not changing anything there's no need to proceed further,
+	 * but store a possible modification of reset_on_fork.
 	 */
 	if (unlikely(policy == p->policy)) {
 		if (fair_policy(policy) && attr->sched_nice != task_nice(p))
@@ -3372,6 +3373,7 @@ recheck:
 		if (dl_policy(policy))
 			goto change;
 
+		p->sched_reset_on_fork = reset_on_fork;
 		task_rq_unlock(rq, p, &flags);
 		return 0;
 	}