cpuidle: Rearrange s2idle-specific idle state entry code

Implement call_cpuidle_s2idle() in analogy with call_cpuidle()
for the s2idle-specific idle state entry and invoke it from
cpuidle_idle_call() to make the s2idle-specific idle entry code
path look more similar to the "regular" idle entry one.

No intentional functional impact.

Signed-off-by: Rafael J. Wysocki <[e-mail]>
Acked-by: Chen Yu <[e-mail]>

drivers/cpuidle/cpuidle.c

···
 #include <linux/mutex.h>
 #include <linux/sched.h>
 #include <linux/sched/clock.h>
-#include <linux/sched/idle.h>
 #include <linux/notifier.h>
 #include <linux/pm_qos.h>
 #include <linux/cpu.h>
···
 	 * be frozen safely.
 	 */
 	index = find_deepest_state(drv, dev, U64_MAX, 0, true);
-	if (index > 0 && !current_clr_polling_and_test())
+	if (index > 0) {
 		enter_s2idle_proper(drv, dev, index);
-
+		local_irq_enable();
+	}
 	return index;
 }
 #endif /* CONFIG_SUSPEND */

kernel/sched/idle.c

···
 	}
 }
 
+static int call_cpuidle_s2idle(struct cpuidle_driver *drv,
+			       struct cpuidle_device *dev)
+{
+	if (current_clr_polling_and_test())
+		return -EBUSY;
+
+	return cpuidle_enter_s2idle(drv, dev);
+}
+
 static int call_cpuidle(struct cpuidle_driver *drv, struct cpuidle_device *dev,
 		      int next_state)
 {
···
 		if (idle_should_enter_s2idle()) {
 			rcu_idle_enter();
 
-			entered_state = cpuidle_enter_s2idle(drv, dev);
-			if (entered_state > 0) {
-				local_irq_enable();
+			entered_state = call_cpuidle_s2idle(drv, dev);
+			if (entered_state > 0)
 				goto exit_idle;
-			}
 
 			rcu_idle_exit();