linux-kernel - [char-misc-next 15/27] mei: bus: fix notification event delivery

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Date:	Sun,  7 Feb 2016 23:35:31 +0200
From:	Tomas Winkler <tomas.winkler@...el.com>
To:	Greg Kroah-Hartman <gregkh@...uxfoundation.org>
Cc:	Alexander Usyskin <alexander.usyskin@...el.com>,
	linux-kernel@...r.kernel.org,
	Tomas Winkler <tomas.winkler@...el.com>
Subject: [char-misc-next 15/27] 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@...el.com>
---
 drivers/misc/mei/bus.c     | 13 +++++++++----
 drivers/misc/mei/client.c  |  4 ++--
 drivers/misc/mei/mei_dev.h |  2 +-
 3 files changed, 12 insertions(+), 7 deletions(-)

diff --git a/drivers/misc/mei/bus.c b/drivers/misc/mei/bus.c
index a40d8e24ecda..990f4f65c35e 100644
--- a/drivers/misc/mei/bus.c
+++ b/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;
 }
 
 /**
diff --git a/drivers/misc/mei/client.c b/drivers/misc/mei/client.c
index 574f7394fb2b..3fd070a698ce 100644
--- a/drivers/misc/mei/client.c
+++ b/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);
 }
 
 /**
diff --git a/drivers/misc/mei/mei_dev.h b/drivers/misc/mei/mei_dev.h
index be97b8f2a883..70c4da015401 100644
--- a/drivers/misc/mei/mei_dev.h
+++ b/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);
-- 
2.4.3