cpuidle: Combine cpuidle_enabled() with cpuidle_select()

Since both cpuidle_enabled() and cpuidle_select() are only called by
cpuidle_idle_call(), it is not really useful to keep them separate
and combining them will help to avoid complicating cpuidle_idle_call()
even further if governors are changed to return error codes sometimes.

This code modification shouldn't lead to any functional changes.

Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>

3 files changed, 13 insertions, 38 deletions

diff --git a/drivers/cpuidle/cpuidle.c b/drivers/cpuidle/cpuidle.c
index 8236746e46bb..f38359f64cc6 100644
--- a/drivers/cpuidle/cpuidle.c
+++ b/drivers/cpuidle/cpuidle.c
@@ -65,26 +65,6 @@ int cpuidle_play_dead(void)
 }
 
 /**
- * cpuidle_enabled - check if the cpuidle framework is ready
- * @dev: cpuidle device for this cpu
- * @drv: cpuidle driver for this cpu
- *
- * Return 0 on success, otherwise:
- * -NODEV : the cpuidle framework is not available
- * -EBUSY : the cpuidle framework is not initialized
- */
-int cpuidle_enabled(struct cpuidle_driver *drv, struct cpuidle_device *dev)
-{
-        if (off || !initialized)
-                return -ENODEV;
-
-        if (!drv || !dev || !dev->enabled)
-                return -EBUSY;
-
-        return 0;
-}
-
-/**
  * cpuidle_enter_state - enter the state and update stats
  * @dev: cpuidle device for this cpu
  * @drv: cpuidle driver for this cpu
@@ -138,6 +118,12 @@ int cpuidle_enter_state(struct cpuidle_device *dev, struct cpuidle_driver *drv,
  */
 int cpuidle_select(struct cpuidle_driver *drv, struct cpuidle_device *dev)
 {
+        if (off || !initialized)
+                return -ENODEV;
+
+        if (!drv || !dev || !dev->enabled)
+                return -EBUSY;
+
         return cpuidle_curr_governor->select(drv, dev);
 }
 
diff --git a/include/linux/cpuidle.h b/include/linux/cpuidle.h
index b0238cba440b..a8d5bd391a26 100644
--- a/include/linux/cpuidle.h
+++ b/include/linux/cpuidle.h
@@ -120,8 +120,6 @@ struct cpuidle_driver {
 #ifdef CONFIG_CPU_IDLE
 extern void disable_cpuidle(void);
 
-extern int cpuidle_enabled(struct cpuidle_driver *drv,
-                          struct cpuidle_device *dev);
 extern int cpuidle_select(struct cpuidle_driver *drv,
                           struct cpuidle_device *dev);
 extern int cpuidle_enter(struct cpuidle_driver *drv,
@@ -149,9 +147,6 @@ extern int cpuidle_play_dead(void);
 extern struct cpuidle_driver *cpuidle_get_cpu_driver(struct cpuidle_device *dev);
 #else
 static inline void disable_cpuidle(void) { }
-static inline int cpuidle_enabled(struct cpuidle_driver *drv,
-                                  struct cpuidle_device *dev)
-{return -ENODEV; }
 static inline int cpuidle_select(struct cpuidle_driver *drv,
                                  struct cpuidle_device *dev)
 {return -ENODEV; }
diff --git a/kernel/sched/idle.c b/kernel/sched/idle.c
index 8f4390a079c7..a8f12247ce7c 100644
--- a/kernel/sched/idle.c
+++ b/kernel/sched/idle.c
@@ -101,19 +101,13 @@ static int cpuidle_idle_call(void)
         rcu_idle_enter();
 
         /*
-         * Check if the cpuidle framework is ready, otherwise fallback
-         * to the default arch specific idle method
+         * Ask the cpuidle framework to choose a convenient idle state.
+         * Fall back to the default arch specific idle method on errors.
          */
-        ret = cpuidle_enabled(drv, dev);
-
-        if (!ret) {
-                /*
-                 * Ask the governor to choose an idle state it thinks
-                 * it is convenient to go to. There is *always* a
-                 * convenient idle state
-                 */
-                next_state = cpuidle_select(drv, dev);
+        next_state = cpuidle_select(drv, dev);
 
+        ret = next_state;
+        if (ret >= 0) {
                 /*
                  * The idle task must be scheduled, it is pointless to
                  * go to idle, just update no idle residency and get
@@ -140,7 +134,7 @@ static int cpuidle_idle_call(void)
                                         CLOCK_EVT_NOTIFY_BROADCAST_ENTER,
                                         &dev->cpu);
 
-                        if (!ret) {
+                        if (ret >= 0) {
                                 trace_cpu_idle_rcuidle(next_state, dev->cpu);
 
                                 /*
@@ -175,7 +169,7 @@ static int cpuidle_idle_call(void)
          * We can't use the cpuidle framework, let's use the default
          * idle routine
          */
-        if (ret)
+        if (ret < 0)
                 arch_cpu_idle();
 
         __current_set_polling();