mei: bus: fix notification event delivery

Call wake_up cl->ev_wait only in case there is no bus client registered
to the event notification.
Second, since we don't have exclusive waiter wake_up_interruptible_all
is not used correctly here.
Signed-off-by: Tomas Winkler <tomas.winkler@intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

drivers/misc/mei/bus.c

@@ -230,25 +230,30 @@ static void mei_cl_bus_event_work(struct work_struct *work)
  * mei_cl_bus_notify_event - schedule notify cb on bus client
  *
  * @cl: host client
+ *
+ * Return: true if event was scheduled
+ *         false if the client is not waiting for event
  */
-void mei_cl_bus_notify_event(struct mei_cl *cl)
+bool mei_cl_bus_notify_event(struct mei_cl *cl)
 {
 	struct mei_cl_device *cldev = cl->cldev;
 
 	if (!cldev || !cldev->event_cb)
-		return;
+		return false;
 
 	if (!(cldev->events_mask & BIT(MEI_CL_EVENT_NOTIF)))
-		return;
+		return false;
 
 	if (!cl->notify_ev)
-		return;
+		return false;
 
 	set_bit(MEI_CL_EVENT_NOTIF, &cldev->events);
 
 	schedule_work(&cldev->event_work);
 
 	cl->notify_ev = false;
+
+	return true;
 }
 
 /**

drivers/misc/mei/client.c

@@ -1363,12 +1363,12 @@ void mei_cl_notify(struct mei_cl *cl)
 
 	cl_dbg(dev, cl, "notify event");
 	cl->notify_ev = true;
-	wake_up_interruptible_all(&cl->ev_wait);
+	if (!mei_cl_bus_notify_event(cl))
+		wake_up_interruptible(&cl->ev_wait);
 
 	if (cl->ev_async)
 		kill_fasync(&cl->ev_async, SIGIO, POLL_PRI);
 
-	mei_cl_bus_notify_event(cl);
 }
 
 /**

drivers/misc/mei/mei_dev.h

@@ -317,7 +317,7 @@ ssize_t __mei_cl_send(struct mei_cl *cl, u8 *buf, size_t length,
 			bool blocking);
 ssize_t __mei_cl_recv(struct mei_cl *cl, u8 *buf, size_t length);
 bool mei_cl_bus_rx_event(struct mei_cl *cl);
-void mei_cl_bus_notify_event(struct mei_cl *cl);
+bool mei_cl_bus_notify_event(struct mei_cl *cl);
 void mei_cl_bus_remove_devices(struct mei_device *bus);
 int mei_cl_bus_init(void);
 void mei_cl_bus_exit(void);