V4L/DVB (8022): saa7134: fix race between opening and closing the device

decrementing dev->empress_users should be done as last action of ts_release,
because it sleeps and write access to dev->empress_started is not protected
in any way
(additionally closing thread could mute audio after opening thread unmuted it)

Signed-off-by: Marcin Slusarz <marcin.slusarz@gmail.com>
Signed-off-by: Mauro Carvalho Chehab <mchehab@infradead.org>

1 files changed, 2 insertions, 1 deletions

diff --git a/drivers/media/video/saa7134/saa7134-empress.c b/drivers/media/video/saa7134/saa7134-empress.c
index 94b2585bdf5b..1c8cd0ef4a65 100644
--- a/drivers/media/video/saa7134/saa7134-empress.c
+++ b/drivers/media/video/saa7134/saa7134-empress.c
@@ -112,7 +112,6 @@ static int ts_release(struct inode *inode, struct file *file)
 
         videobuf_stop(&dev->empress_tsq);
         videobuf_mmap_free(&dev->empress_tsq);
-        dev->empress_users--;
 
         /* stop the encoder */
         ts_reset_encoder(dev);
@@ -121,6 +120,8 @@ static int ts_release(struct inode *inode, struct file *file)
         saa_writeb(SAA7134_AUDIO_MUTE_CTRL,
                 saa_readb(SAA7134_AUDIO_MUTE_CTRL) | (1 << 6));
 
+        dev->empress_users--;
+
         return 0;
 }