sched: Clean up ttwu() rq locking

Since set_task_clock() doesn't rely on rq->clock anymore we can simplyfy
the mess in ttwu().

Optimize things a bit by not fiddling with the IRQ state there.

Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
LKML-Reference: <new-submission>
Signed-off-by: Ingo Molnar <mingo@elte.hu>

kernel/sched.c

@@ -2371,17 +2371,14 @@ static int try_to_wake_up(struct task_struct *p, unsigned int state,
 	if (task_contributes_to_load(p))
 		rq->nr_uninterruptible--;
 	p->state = TASK_WAKING;
-	task_rq_unlock(rq, &flags);
+	__task_rq_unlock(rq);
 
 	cpu = select_task_rq(p, SD_BALANCE_WAKE, wake_flags);
-	if (cpu != orig_cpu) {
-		local_irq_save(flags);
-		rq = cpu_rq(cpu);
-		update_rq_clock(rq);
+	if (cpu != orig_cpu)
 		set_task_cpu(p, cpu);
-		local_irq_restore(flags);
-	}
-	rq = task_rq_lock(p, &flags);
+
+	rq = __task_rq_lock(p);
+	update_rq_clock(rq);
 
 	WARN_ON(p->state != TASK_WAKING);
 	cpu = task_cpu(p);