sched: clean up sched_fork()

The adjusting sched_class is a missing part of the already existing "do
not leak PI boosting priority to the child" at the sched_fork(). This
patch moves the adjusting sched_class from wake_up_new_task() to
sched_fork().

this also shrinks the code a bit:

   text    data     bss     dec     hex filename
  40111    4018     292   44421    ad85 sched.o.before
  40102    4018     292   44412    ad7c sched.o.after
Signed-off-by: Hiroshi Shimamoto <h-shimamoto@ct.jp.nec.com>
Signed-off-by: Dmitry Adamushko <dmitry.adamushko@gmail.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Reviewed-by: Thomas Gleixner <tglx@linutronix.de>

kernel/sched.c

@@ -1663,6 +1663,8 @@ void sched_fork(struct task_struct *p, int clone_flags)
 	 * Make sure we do not leak PI boosting priority to the child:
 	 */
 	p->prio = current->normal_prio;
+	if (!rt_prio(p->prio))
+		p->sched_class = &fair_sched_class;
 
 #if defined(CONFIG_SCHEDSTATS) || defined(CONFIG_TASK_DELAY_ACCT)
 	if (likely(sched_info_on()))
@@ -1698,11 +1700,6 @@ void fastcall wake_up_new_task(struct task_struct *p, unsigned long clone_flags)
 
 	p->prio = effective_prio(p);
 
-	if (rt_prio(p->prio))
-		p->sched_class = &rt_sched_class;
-	else
-		p->sched_class = &fair_sched_class;
-
 	if (task_cpu(p) != this_cpu || !p->sched_class->task_new ||
 							!current->se.on_rq) {
 		activate_task(rq, p, 0);