sched: fix cpu hotplug, cleanup

Clean up __migrate_task(): to just have separate "done" and "fail"
cases, instead of that "out" case with random error behavior.
Signed-off-by: NIngo Molnar <mingo@elte.hu>

kernel/sched.c

@@ -5621,13 +5621,11 @@ static int __migrate_task(struct task_struct *p, int src_cpu, int dest_cpu)
 
 	double_rq_lock(rq_src, rq_dest);
 	/* Already moved. */
-	if (task_cpu(p) != src_cpu) {
-		ret = 1;
-		goto out;
-	}
+	if (task_cpu(p) != src_cpu)
+		goto done;
 	/* Affinity changed (again). */
 	if (!cpu_isset(dest_cpu, p->cpus_allowed))
-		goto out;
+		goto fail;
 
 	on_rq = p->se.on_rq;
 	if (on_rq)
@@ -5638,8 +5636,9 @@ static int __migrate_task(struct task_struct *p, int src_cpu, int dest_cpu)
 		activate_task(rq_dest, p, 0);
 		check_preempt_curr(rq_dest, p);
 	}
+done:
 	ret = 1;
-out:
+fail:
 	double_rq_unlock(rq_src, rq_dest);
 	return ret;
 }