nohz: Remove ts->Einidle checks before restarting the tick

ts->inidle is set by tick_nohz_idle_enter() and unset by
tick_nohz_idle_exit(). However these two calls are assumed
to be always paired. This means that by the time we call
tick_nohz_idle_exit(), ts->inidle is supposed to be always
set to 1.

Remove the checks for ts->inidle in tick_nohz_idle_exit().
This simplifies a bit the code and improves its debuggability
(ie: ensure the call is paired with a tick_nohz_idle_enter()
call).

Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com>
Reviewed-by: Yong Zhang <yong.zhang0@gmail.com>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: John Stultz <john.stultz@linaro.org>
Cc: Ingo Molnar <mingo@elte.hu>
Link: http://lkml.kernel.org/r/1327427984-23282-2-git-send-email-fweisbec@gmail.com
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>

kernel/time/tick-sched.c

@@ -558,20 +558,21 @@ void tick_nohz_idle_exit(void)
 
 	local_irq_disable();
 
-	if (ts->idle_active || (ts->inidle && ts->tick_stopped))
+	WARN_ON_ONCE(!ts->inidle);
+
+	ts->inidle = 0;
+
+	if (ts->idle_active || ts->tick_stopped)
 		now = ktime_get();
 
 	if (ts->idle_active)
 		tick_nohz_stop_idle(cpu, now);
 
-	if (!ts->inidle || !ts->tick_stopped) {
-		ts->inidle = 0;
+	if (!ts->tick_stopped) {
 		local_irq_enable();
 		return;
 	}
 
-	ts->inidle = 0;
-
 	/* Update jiffies first */
 	select_nohz_load_balancer(0);
 	tick_do_update_jiffies64(now);