V4L/DVB (9647): em28xx: void having two concurrent control URB's

Now that we have a polling task for IR, there's a race condition, since
IR can be polling while other operations are being doing. Also, we are
now sharing the same urb_buf for both read and write control urb
operations. So, we need a mutex.

Thanks to Davin Heitmueller <devin.heitmueller@gmail.com> for warning me.

Signed-off-by: Mauro Carvalho Chehab <mchehab@redhat.com>

1 files changed, 1 insertions, 0 deletions

diff --git a/drivers/media/video/em28xx/em28xx.h b/drivers/media/video/em28xx/em28xx.h
index 1adf3d9d9bff..5956e9b3062f 100644
--- a/drivers/media/video/em28xx/em28xx.h
+++ b/drivers/media/video/em28xx/em28xx.h
@@ -433,6 +433,7 @@ struct em28xx {
 
         /* locks */
         struct mutex lock;
+        struct mutex ctrl_urb_lock;     /* protects urb_buf */
         /* spinlock_t queue_lock; */
         struct list_head inqueue, outqueue;
         wait_queue_head_t open, wait_frame, wait_stream;