PM: runtime: Improve path in rpm_idle() when no callback

When pm_runtime_no_callbacks() has been called for a struct device to set
the dev->power.no_callbacks flag for it, it enables rpm_idle() to take a
slightly quicker path by assuming that a ->runtime_idle() callback would
have returned 0 to indicate success.

A device that does not have the dev->power.no_callbacks flag set for it,
may still be missing a corresponding ->runtime_idle() callback, in which
case the slower path in rpm_idle() is taken. Let's improve the behaviour
for this case, by aligning code to the quicker path.

Signed-off-by: Ulf Hansson <ulf.hansson@linaro.org>
Acked-by: Alan Stern <stern@rowland.harvard.edu>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>

diff --git a/drivers/base/power/runtime.c b/drivers/base/power/runtime.c
index b570848d23e0eb9f9fe6d13ec9e75263ae737586..68bebbf81347f55f09f4b1870307ec9d5062e9b7 100644 (file)
--- a/drivers/base/power/runtime.c
+++ b/drivers/base/power/runtime.c
@@ -446,7 +446,10 @@ static int rpm_idle(struct device *dev, int rpmflags)
        /* Pending requests need to be canceled. */
        dev->power.request = RPM_REQ_NONE;
 
-       if (dev->power.no_callbacks)
+       callback = RPM_GET_CALLBACK(dev, runtime_idle);
+
+       /* If no callback assume success. */
+       if (!callback || dev->power.no_callbacks)
                goto out;
 
        /* Carry out an asynchronous or a synchronous idle notification. */
@@ -462,10 +465,7 @@ static int rpm_idle(struct device *dev, int rpmflags)
 
        dev->power.idle_notification = true;
 
-       callback = RPM_GET_CALLBACK(dev, runtime_idle);
-
-       if (callback)
-               retval = __rpm_callback(callback, dev);
+       retval = __rpm_callback(callback, dev);
 
        dev->power.idle_notification = false;
        wake_up_all(&dev->power.wait_queue);