1 files changed, 14 insertions, 8 deletions

diff --git a/drivers/media/video/cx18/cx18-dvb.c b/drivers/media/video/cx18/cx18-dvb.c
index 71ad2d1b4c2..0ae2c2e1eab 100644
--- a/drivers/media/video/cx18/cx18-dvb.c
+++ b/drivers/media/video/cx18/cx18-dvb.c
@@ -213,10 +213,14 @@ static int cx18_dvb_start_feed(struct dvb_demux_feed *feed)
 {
 	struct dvb_demux *demux = feed->demux;
 	struct cx18_stream *stream = (struct cx18_stream *) demux->priv;
-	struct cx18 *cx = stream->cx;
+	struct cx18 *cx;
 	int ret;
 	u32 v;
 
+	if (!stream)
+		return -EINVAL;
+
+	cx = stream->cx;
 	CX18_DEBUG_INFO("Start feed: pid = 0x%x index = %d\n",
 			feed->pid, feed->index);
 
@@ -253,12 +257,10 @@ static int cx18_dvb_start_feed(struct dvb_demux_feed *feed)
 	if (!demux->dmx.frontend)
 		return -EINVAL;
 
-	if (!stream)
-		return -EINVAL;
-
 	mutex_lock(&stream->dvb.feedlock);
 	if (stream->dvb.feeding++ == 0) {
 		CX18_DEBUG_INFO("Starting Transport DMA\n");
+		mutex_lock(&cx->serialize_lock);
 		set_bit(CX18_F_S_STREAMING, &stream->s_flags);
 		ret = cx18_start_v4l2_encode_stream(stream);
 		if (ret < 0) {
@@ -267,6 +269,7 @@ static int cx18_dvb_start_feed(struct dvb_demux_feed *feed)
 			if (stream->dvb.feeding == 0)
 				clear_bit(CX18_F_S_STREAMING, &stream->s_flags);
 		}
+		mutex_unlock(&cx->serialize_lock);
 	} else
 		ret = 0;
 	mutex_unlock(&stream->dvb.feedlock);
@@ -279,17 +282,20 @@ static int cx18_dvb_stop_feed(struct dvb_demux_feed *feed)
 {
 	struct dvb_demux *demux = feed->demux;
 	struct cx18_stream *stream = (struct cx18_stream *)demux->priv;
-	struct cx18 *cx = stream->cx;
+	struct cx18 *cx;
 	int ret = -EINVAL;
 
-	CX18_DEBUG_INFO("Stop feed: pid = 0x%x index = %d\n",
-			feed->pid, feed->index);
-
 	if (stream) {
+		cx = stream->cx;
+		CX18_DEBUG_INFO("Stop feed: pid = 0x%x index = %d\n",
+				feed->pid, feed->index);
+
 		mutex_lock(&stream->dvb.feedlock);
 		if (--stream->dvb.feeding == 0) {
 			CX18_DEBUG_INFO("Stopping Transport DMA\n");
+			mutex_lock(&cx->serialize_lock);
 			ret = cx18_stop_v4l2_encode_stream(stream, 0);
+			mutex_unlock(&cx->serialize_lock);
 		} else
 			ret = 0;
 		mutex_unlock(&stream->dvb.feedlock);