PM / Runtime: Use deferred_resume flag in pm_request_resume

This patch (as1307) adds a small optimization to
__pm_request_resume().  If the device is currently being suspended,
there's no need to queue a work routine to resume it.  Setting the
deferred_resume flag will suffice.  (There's also a minor improvement
to the function's code layout: An unnecessary "else" is removed.)

Also, the patch clarifies the usage of the deferred_resume flag.  It
is meaningful only while a suspend is in progress, so it should be
cleared just before a suspend starts, not just after one ends.

Signed-off-by: Alan Stern <stern@rowland.harvard.edu>
Signed-off-by: Rafael J. Wysocki <rjw@sisk.pl>

1 files changed, 7 insertions, 4 deletions

diff --git a/drivers/base/power/runtime.c b/drivers/base/power/runtime.c
index 0a4b75f834c0..6e8577d1f750 100644
--- a/drivers/base/power/runtime.c
+++ b/drivers/base/power/runtime.c
@@ -185,6 +185,7 @@ int __pm_runtime_suspend(struct device *dev, bool from_wq)
         }
 
         dev->power.runtime_status = RPM_SUSPENDING;
+        dev->power.deferred_resume = false;
 
         if (dev->bus && dev->bus->pm && dev->bus->pm->runtime_suspend) {
                 spin_unlock_irq(&dev->power.lock);
@@ -200,7 +201,6 @@ int __pm_runtime_suspend(struct device *dev, bool from_wq)
         if (retval) {
                 dev->power.runtime_status = RPM_ACTIVE;
                 pm_runtime_cancel_pending(dev);
-                dev->power.deferred_resume = false;
 
                 if (retval == -EAGAIN || retval == -EBUSY) {
                         notify = true;
@@ -217,7 +217,6 @@ int __pm_runtime_suspend(struct device *dev, bool from_wq)
         wake_up_all(&dev->power.wait_queue);
 
         if (dev->power.deferred_resume) {
-                dev->power.deferred_resume = false;
                 __pm_runtime_resume(dev, false);
                 retval = -EAGAIN;
                 goto out;
@@ -659,13 +658,17 @@ static int __pm_request_resume(struct device *dev)
 
         pm_runtime_deactivate_timer(dev);
 
+        if (dev->power.runtime_status == RPM_SUSPENDING) {
+                dev->power.deferred_resume = true;
+                return retval;
+        }
         if (dev->power.request_pending) {
                 /* If non-resume request is pending, we can overtake it. */
                 dev->power.request = retval ? RPM_REQ_NONE : RPM_REQ_RESUME;
                 return retval;
-        } else if (retval) {
-                return retval;
         }
+        if (retval)
+                return retval;
 
         dev->power.request = RPM_REQ_RESUME;
         dev->power.request_pending = true;