media: ov9734: hold lock to check streaming state

The lock in ov9734 is used to protect the streaming state and
serialize the stream on and off callbacks, it should be hold before
checking the streaming state in ov9734_set_stream().

Reported-by: Tomasz Figa <tfiga@chromium.org>
Reported-by: Sergey Senozhatsky <senozhatsky@chromium.org>
Signed-off-by: Bingbu Cao <bingbu.cao@intel.com>
Reviewed-by: Sergey Senozhatsky <sergey.senozhatsky@gmail.com>
Signed-off-by: Sakari Ailus <sakari.ailus@linux.intel.com>
Signed-off-by: Mauro Carvalho Chehab <mchehab+huawei@kernel.org>

diff --git a/drivers/media/i2c/ov9734.c b/drivers/media/i2c/ov9734.c
index 4b9a2e9288e7c25fe024323c3a2536fc5f1d7a57..e212465489e8f583bd19a4f529ac7c2b0a183228 100644 (file)
--- a/drivers/media/i2c/ov9734.c
+++ b/drivers/media/i2c/ov9734.c
@@ -637,10 +637,12 @@ static int ov9734_set_stream(struct v4l2_subdev *sd, int enable)
        struct i2c_client *client = v4l2_get_subdevdata(sd);
        int ret = 0;
 
-       if (ov9734->streaming == enable)
+       mutex_lock(&ov9734->mutex);
+       if (ov9734->streaming == enable) {
+               mutex_unlock(&ov9734->mutex);
                return 0;
+       }
 
-       mutex_lock(&ov9734->mutex);
        if (enable) {
                ret = pm_runtime_get_sync(&client->dev);
                if (ret < 0) {