sched/idle: Reflow cpuidle_idle_call()

Apply goto to reduce lines and nesting levels.

Signed-off-by: Peter Zijlstra <peterz@infradead.org>
Acked-by: Nicolas Pitre <nicolas.pitre@linaro.org>
Cc: Daniel Lezcano <daniel.lezcano@linaro.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Link: http://lkml.kernel.org/n/tip-cc6vb0snt3sr7op6rlbfeqfh@git.kernel.org
Signed-off-by: Ingo Molnar <mingo@kernel.org>

kernel/sched/idle.c

@@ -73,7 +73,7 @@ static int cpuidle_idle_call(void)
 {
 	struct cpuidle_device *dev = __this_cpu_read(cpuidle_devices);
 	struct cpuidle_driver *drv = cpuidle_get_cpu_driver(dev);
-	int next_state, entered_state, ret;
+	int next_state, entered_state;
 	bool broadcast;
 
 	/*
@@ -102,9 +102,20 @@ static int cpuidle_idle_call(void)
 	 * Check if the cpuidle framework is ready, otherwise fallback
 	 * to the default arch specific idle method
 	 */
-	ret = cpuidle_enabled(drv, dev);
+	if (cpuidle_enabled(drv, dev)) {
+use_default:
+		/*
+		 * We can't use the cpuidle framework, let's use the default
+		 * idle routine.
+		 */
+		if (current_clr_polling_and_test())
+			local_irq_enable();
+		else
+			arch_cpu_idle();
+
+		goto exit_idle;
+	}
 
-	if (!ret) {
 	/*
 	 * Ask the governor to choose an idle state it thinks
 	 * it is convenient to go to. There is *always* a
@@ -121,71 +132,45 @@ static int cpuidle_idle_call(void)
 		dev->last_residency = 0;
 		entered_state = next_state;
 		local_irq_enable();
-		} else {
+		goto exit_idle;
-			broadcast = !!(drv->states[next_state].flags &
-				       CPUIDLE_FLAG_TIMER_STOP);
-
-			if (broadcast) {
-				/*
-				 * Tell the time framework to switch
-				 * to a broadcast timer because our
-				 * local timer will be shutdown. If a
-				 * local timer is used from another
-				 * cpu as a broadcast timer, this call
-				 * may fail if it is not available
-				 */
-				ret = clockevents_notify(
-					CLOCK_EVT_NOTIFY_BROADCAST_ENTER,
-					&dev->cpu);
 	}
 
-			if (!ret) {
+	broadcast = !!(drv->states[next_state].flags & CPUIDLE_FLAG_TIMER_STOP);
+
+	/*
+	 * Tell the time framework to switch to a broadcast timer
+	 * because our local timer will be shutdown. If a local timer
+	 * is used from another cpu as a broadcast timer, this call may
+	 * fail if it is not available
+	 */
+	if (broadcast &&
+	    clockevents_notify(CLOCK_EVT_NOTIFY_BROADCAST_ENTER, &dev->cpu))
+		goto use_default;
+
 	trace_cpu_idle_rcuidle(next_state, dev->cpu);
 
 	/*
-				 * Enter the idle state previously
+	 * Enter the idle state previously returned by the governor decision.
-				 * returned by the governor
+	 * This function will block until an interrupt occurs and will take
-				 * decision. This function will block
+	 * care of re-enabling the local interrupts
-				 * until an interrupt occurs and will
-				 * take care of re-enabling the local
-				 * interrupts
 	 */
-				entered_state = cpuidle_enter(drv, dev,
+	entered_state = cpuidle_enter(drv, dev, next_state);
-							      next_state);
 
-				trace_cpu_idle_rcuidle(PWR_EVENT_EXIT,
+	trace_cpu_idle_rcuidle(PWR_EVENT_EXIT, dev->cpu);
-						       dev->cpu);
 
 	if (broadcast)
-					clockevents_notify(
+		clockevents_notify(CLOCK_EVT_NOTIFY_BROADCAST_EXIT, &dev->cpu);
-						CLOCK_EVT_NOTIFY_BROADCAST_EXIT,
-						&dev->cpu);
 
 	/*
-				 * Give the governor an opportunity to reflect on the
+	 * Give the governor an opportunity to reflect on the outcome
-				 * outcome
 	 */
 	cpuidle_reflect(dev, entered_state);
-			}
-		}
-	}
-
-	/*
-	 * We can't use the cpuidle framework, let's use the default
-	 * idle routine
-	 */
-	if (ret) {
-		if (!current_clr_polling_and_test())
-			arch_cpu_idle();
-		else
-			local_irq_enable();
-	}
 
+exit_idle:
 	__current_set_polling();
 
 	/*
-	 * It is up to the idle functions to enable back the local
+	 * It is up to the idle functions to reenable local interrupts
-	 * interrupt
 	 */
 	if (WARN_ON_ONCE(irqs_disabled()))
 		local_irq_enable();