sched / idle: Eliminate the "reflect" check from cpuidle_idle_call()

Since cpuidle_reflect() should only be called if the idle state
to enter was selected by cpuidle_select(), there is the "reflect"
variable in cpuidle_idle_call() whose value is used to determine
whether or not that is the case.

However, if the entire code run between the conditional setting
"reflect" and the call to cpuidle_reflect() is moved to a separate
function, it will be possible to call that new function in both
branches of the conditional, in which case cpuidle_reflect() will
only need to be called from one of them too and the "reflect"
variable won't be necessary any more.

This eliminates one check made by cpuidle_idle_call() on the majority
of its invocations, so change the code as described.

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>

1 files changed, 46 insertions, 44 deletions

diff --git a/kernel/sched/idle.c b/kernel/sched/idle.c
index ae7c0be90d16..9c919b42f846 100644
--- a/kernel/sched/idle.c
+++ b/kernel/sched/idle.c
@@ -79,6 +79,46 @@ static void default_idle_call(void)
                 arch_cpu_idle();
 }
 
+static int call_cpuidle(struct cpuidle_driver *drv, struct cpuidle_device *dev,
+                      int next_state)
+{
+        int entered_state;
+
+        /* Fall back to the default arch idle method on errors. */
+        if (next_state < 0) {
+                default_idle_call();
+                return next_state;
+        }
+
+        /*
+         * The idle task must be scheduled, it is pointless to go to idle, just
+         * update no idle residency and return.
+         */
+        if (current_clr_polling_and_test()) {
+                dev->last_residency = 0;
+                local_irq_enable();
+                return -EBUSY;
+        }
+
+        /* Take note of the planned idle state. */
+        idle_set_state(this_rq(), &drv->states[next_state]);
+
+        /*
+         * Enter the idle state previously returned by the governor decision.
+         * This function will block until an interrupt occurs and will take
+         * care of re-enabling the local interrupts
+         */
+        entered_state = cpuidle_enter(drv, dev, next_state);
+
+        /* The cpu is no longer idle or about to enter idle. */
+        idle_set_state(this_rq(), NULL);
+
+        if (entered_state == -EBUSY)
+                default_idle_call();
+
+        return entered_state;
+}
+
 /**
  * cpuidle_idle_call - the main idle function
  *
@@ -93,7 +133,6 @@ static void 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;
-        bool reflect;
 
         /*
          * Check if the idle task must be rescheduled. If it is the
@@ -138,56 +177,19 @@ static void cpuidle_idle_call(void)
                         goto exit_idle;
                 }
 
-                reflect = false;
                 next_state = cpuidle_find_deepest_state(drv, dev);
+                call_cpuidle(drv, dev, next_state);
         } else {
-                reflect = true;
                 /*
                  * Ask the cpuidle framework to choose a convenient idle state.
                  */
                 next_state = cpuidle_select(drv, dev);
-        }
-        /* Fall back to the default arch idle method on errors. */
-        if (next_state < 0) {
-                default_idle_call();
-                goto exit_idle;
-        }
-
-        /*
-         * The idle task must be scheduled, it is pointless to
-         * go to idle, just update no idle residency and get
-         * out of this function
-         */
-        if (current_clr_polling_and_test()) {
-                dev->last_residency = 0;
-                entered_state = next_state;
-                local_irq_enable();
-                goto exit_idle;
-        }
-
-        /* Take note of the planned idle state. */
-        idle_set_state(this_rq(), &drv->states[next_state]);
-
-        /*
-         * Enter the idle state previously returned by the governor decision.
-         * This function will block until an interrupt occurs and will take
-         * care of re-enabling the local interrupts
-         */
-        entered_state = cpuidle_enter(drv, dev, next_state);
-
-        /* The cpu is no longer idle or about to enter idle. */
-        idle_set_state(this_rq(), NULL);
-
-        if (entered_state == -EBUSY) {
-                default_idle_call();
-                goto exit_idle;
-        }
-
-        /*
-         * Give the governor an opportunity to reflect on the outcome
-         */
-        if (reflect)
+                entered_state = call_cpuidle(drv, dev, next_state);
+                /*
+                 * Give the governor an opportunity to reflect on the outcome
+                 */
                 cpuidle_reflect(dev, entered_state);
+        }
 
 exit_idle:
         __current_set_polling();