linux-kernel - [char-misc-next 2/3] mei: bus: stop wait for read during cl state transition

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Date:	Mon,  2 Sep 2013 13:29:46 +0300
From:	Tomas Winkler <tomas.winkler@...el.com>
To:	gregkh@...uxfoundation.org
Cc:	arnd@...db.de, linux-kernel@...r.kernel.org,
	Tomas Winkler <tomas.winkler@...el.com>,
	<stable@...r.kernel.org>
Subject: [char-misc-next 2/3] mei: bus: stop wait for read during cl state transition

Bus layer omitted check for client state transition while waiting
for read completion
The client state transition may occur for example as result
of firmware initiated reset

Add mei_cl_is_transitioning wrapper to reduce the code
repetition.:

Cc:  <stable@...r.kernel.org> # 3.9+
Signed-off-by: Tomas Winkler <tomas.winkler@...el.com>
---
 drivers/misc/mei/bus.c    |  5 ++++-
 drivers/misc/mei/client.h |  6 ++++++
 drivers/misc/mei/main.c   | 11 ++++-------
 3 files changed, 14 insertions(+), 8 deletions(-)

diff --git a/drivers/misc/mei/bus.c b/drivers/misc/mei/bus.c
index a150a42..f5dabb3 100644
--- a/drivers/misc/mei/bus.c
+++ b/drivers/misc/mei/bus.c
@@ -295,10 +295,13 @@ int __mei_cl_recv(struct mei_cl *cl, u8 *buf, size_t length)
 
 	if (cl->reading_state != MEI_READ_COMPLETE &&
 	    !waitqueue_active(&cl->rx_wait)) {
+
 		mutex_unlock(&dev->device_lock);
 
 		if (wait_event_interruptible(cl->rx_wait,
-				(MEI_READ_COMPLETE == cl->reading_state))) {
+				cl->reading_state == MEI_READ_COMPLETE  ||
+				mei_cl_is_transitioning(cl))) {
+
 			if (signal_pending(current))
 				return -EINTR;
 			return -ERESTARTSYS;
diff --git a/drivers/misc/mei/client.h b/drivers/misc/mei/client.h
index 9eb031e..892cc42 100644
--- a/drivers/misc/mei/client.h
+++ b/drivers/misc/mei/client.h
@@ -90,6 +90,12 @@ static inline bool mei_cl_is_connected(struct mei_cl *cl)
 		cl->dev->dev_state == MEI_DEV_ENABLED &&
 		cl->state == MEI_FILE_CONNECTED);
 }
+static inline bool mei_cl_is_transitioning(struct mei_cl *cl)
+{
+	return (MEI_FILE_INITIALIZING == cl->state ||
+		MEI_FILE_DISCONNECTED == cl->state ||
+		MEI_FILE_DISCONNECTING == cl->state);
+}
 
 bool mei_cl_is_other_connecting(struct mei_cl *cl);
 int mei_cl_disconnect(struct mei_cl *cl);
diff --git a/drivers/misc/mei/main.c b/drivers/misc/mei/main.c
index 7404584..b8f8604 100644
--- a/drivers/misc/mei/main.c
+++ b/drivers/misc/mei/main.c
@@ -255,19 +255,16 @@ static ssize_t mei_read(struct file *file, char __user *ubuf,
 		mutex_unlock(&dev->device_lock);
 
 		if (wait_event_interruptible(cl->rx_wait,
-			(MEI_READ_COMPLETE == cl->reading_state ||
-			 MEI_FILE_INITIALIZING == cl->state ||
-			 MEI_FILE_DISCONNECTED == cl->state ||
-			 MEI_FILE_DISCONNECTING == cl->state))) {
+				MEI_READ_COMPLETE == cl->reading_state ||
+				mei_cl_is_transitioning(cl))) {
+
 			if (signal_pending(current))
 				return -EINTR;
 			return -ERESTARTSYS;
 		}
 
 		mutex_lock(&dev->device_lock);
-		if (MEI_FILE_INITIALIZING == cl->state ||
-		    MEI_FILE_DISCONNECTED == cl->state ||
-		    MEI_FILE_DISCONNECTING == cl->state) {
+		if (mei_cl_is_transitioning(cl)) {
 			rets = -EBUSY;
 			goto out;
 		}
-- 
1.8.3.1

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