Power management fix for 3.11-rc6

- The removal of delayed_work_pending() checks from kernel/power/qos.c
   done in 3.9 introduced a deadlock in pm_qos_work_fn().  Fix from
   Stephen Boyd.
 
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Merge tag 'pm-3.11-rc6' of git://git.kernel.org/pub/scm/linux/kernel/git/rafael/linux-pm

Pull power management fix from Rafael Wysocki:
 "The removal of delayed_work_pending() checks from kernel/power/qos.c
  done in 3.9 introduced a deadlock in pm_qos_work_fn().

  Fix from Stephen Boyd"

* tag 'pm-3.11-rc6' of git://git.kernel.org/pub/scm/linux/kernel/git/rafael/linux-pm:
  PM / QoS: Fix workqueue deadlock when using pm_qos_update_request_timeout()

kernel/power/qos.c

@@ -296,6 +296,17 @@ int pm_qos_request_active(struct pm_qos_request *req)
 }
 EXPORT_SYMBOL_GPL(pm_qos_request_active);
 
+static void __pm_qos_update_request(struct pm_qos_request *req,
+			   s32 new_value)
+{
+	trace_pm_qos_update_request(req->pm_qos_class, new_value);
+
+	if (new_value != req->node.prio)
+		pm_qos_update_target(
+			pm_qos_array[req->pm_qos_class]->constraints,
+			&req->node, PM_QOS_UPDATE_REQ, new_value);
+}
+
 /**
  * pm_qos_work_fn - the timeout handler of pm_qos_update_request_timeout
  * @work: work struct for the delayed work (timeout)
@@ -308,7 +319,7 @@ static void pm_qos_work_fn(struct work_struct *work)
 						  struct pm_qos_request,
 						  work);
 
-	pm_qos_update_request(req, PM_QOS_DEFAULT_VALUE);
+	__pm_qos_update_request(req, PM_QOS_DEFAULT_VALUE);
 }
 
 /**
@@ -364,12 +375,7 @@ void pm_qos_update_request(struct pm_qos_request *req,
 	}
 
 	cancel_delayed_work_sync(&req->work);
-
-	trace_pm_qos_update_request(req->pm_qos_class, new_value);
-	if (new_value != req->node.prio)
-		pm_qos_update_target(
-			pm_qos_array[req->pm_qos_class]->constraints,
-			&req->node, PM_QOS_UPDATE_REQ, new_value);
+	__pm_qos_update_request(req, new_value);
 }
 EXPORT_SYMBOL_GPL(pm_qos_update_request);