cpuidle: Check the sign of index in cpuidle_reflect()

Avoid calling the governor's ->reflect method if the state index
passed to cpuidle_reflect() is negative.

This allows the analogous check to be dropped from menu_reflect(),
so do that too, and ensures that arbitrary error codes can be
passed to cpuidle_reflect() as the index with no adverse
consequences.

Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Reviewed-by: Daniel Lezcano <daniel.lezcano@linaro.org>
Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org>

drivers/cpuidle/cpuidle.c

@@ -249,7 +249,7 @@ int cpuidle_enter(struct cpuidle_driver *drv, struct cpuidle_device *dev,
  */
 void cpuidle_reflect(struct cpuidle_device *dev, int index)
 {
-	if (cpuidle_curr_governor->reflect)
+	if (cpuidle_curr_governor->reflect && index >= 0)
 		cpuidle_curr_governor->reflect(dev, index);
 }
 

drivers/cpuidle/governors/menu.c

@@ -367,9 +367,9 @@ static int menu_select(struct cpuidle_driver *drv, struct cpuidle_device *dev)
 static void menu_reflect(struct cpuidle_device *dev, int index)
 {
 	struct menu_device *data = this_cpu_ptr(&menu_devices);
+
 	data->last_state_idx = index;
-	if (index >= 0)
-		data->needs_update = 1;
+	data->needs_update = 1;
 }
 
 /**