media: omap4iss: Acquire graph mutex for graph traversal

Acquire the graph_mutex for traversing the media graph. This seems to have
been missing all the time.
Signed-off-by: Sakari Ailus <sakari.ailus@linux.intel.com>
Signed-off-by: Mauro Carvalho Chehab <mchehab+huawei@kernel.org>

drivers/staging/media/omap4iss/iss.c

@@ -456,6 +456,8 @@ static int iss_pipeline_enable(struct iss_pipeline *pipe,
 
 	pipe->do_propagation = false;
 
+	mutex_lock(&iss->media_dev.graph_mutex);
+
 	entity = &pipe->output->video.entity;
 	while (1) {
 		pad = &entity->pads[0];
@@ -472,6 +474,7 @@ static int iss_pipeline_enable(struct iss_pipeline *pipe,
 		ret = v4l2_subdev_call(subdev, video, s_stream, mode);
 		if (ret < 0 && ret != -ENOIOCTLCMD) {
 			iss_pipeline_disable(pipe, entity);
+			mutex_unlock(&iss->media_dev.graph_mutex);
 			return ret;
 		}
 
@@ -480,7 +483,9 @@ static int iss_pipeline_enable(struct iss_pipeline *pipe,
 			pipe->do_propagation = true;
 	}
 
+	mutex_unlock(&iss->media_dev.graph_mutex);
 	iss_print_status(pipe->output->iss);
+
 	return 0;
 }
 

drivers/staging/media/omap4iss/iss_video.c

@@ -854,6 +854,7 @@ iss_video_streamon(struct file *file, void *fh, enum v4l2_buf_type type)
 	struct iss_video *video = video_drvdata(file);
 	struct media_graph graph;
 	struct media_entity *entity = &video->video.entity;
+	struct media_device *mdev = entity->graph_obj.mdev;
 	enum iss_pipeline_state state;
 	struct iss_pipeline *pipe;
 	struct iss_video *far_end;
@@ -890,9 +891,11 @@ iss_video_streamon(struct file *file, void *fh, enum v4l2_buf_type type)
 	if (ret < 0)
 		goto err_media_pipeline_start;
 
+	mutex_lock(&mdev->graph_mutex);
 	media_graph_walk_start(&graph, entity);
 	while ((entity = media_graph_walk_next(&graph)))
 		media_entity_enum_set(&pipe->ent_enum, entity);
+	mutex_unlock(&mdev->graph_mutex);
 
 	/*
 	 * Verify that the currently configured format matches the output of