[media] media: Always keep a graph walk large enough around

Re-create the graph walk object as needed in order to have one large enough
available for all entities in the graph.

This enumeration is used for pipeline power management in the future.

[mchehab@osg.samsung.com: fix documentation bug:
 " warning: bad line: graph_mutex"]

Signed-off-by: Sakari Ailus <sakari.ailus@linux.intel.com>
Signed-off-by: Mauro Carvalho Chehab <mchehab@osg.samsung.com>

1 files changed, 21 insertions, 0 deletions

diff --git a/drivers/media/media-device.c b/drivers/media/media-device.c
index 17cd349e485f..a2353ecab687 100644
--- a/drivers/media/media-device.c
+++ b/drivers/media/media-device.c
@@ -589,6 +589,26 @@ int __must_check media_device_register_entity(struct media_device *mdev,
 
 	spin_unlock(&mdev->lock);
 
+	mutex_lock(&mdev->graph_mutex);
+	if (mdev->entity_internal_idx_max
+	    >= mdev->pm_count_walk.ent_enum.idx_max) {
+		struct media_entity_graph new = { .top = 0 };
+
+		/*
+		 * Initialise the new graph walk before cleaning up
+		 * the old one in order not to spoil the graph walk
+		 * object of the media device if graph walk init fails.
+		 */
+		ret = media_entity_graph_walk_init(&new, mdev);
+		if (ret) {
+			mutex_unlock(&mdev->graph_mutex);
+			return ret;
+		}
+		media_entity_graph_walk_cleanup(&mdev->pm_count_walk);
+		mdev->pm_count_walk = new;
+	}
+	mutex_unlock(&mdev->graph_mutex);
+
 	return 0;
 }
 EXPORT_SYMBOL_GPL(media_device_register_entity);
@@ -667,6 +687,7 @@ void media_device_cleanup(struct media_device *mdev)
 {
 	ida_destroy(&mdev->entity_internal_idx);
 	mdev->entity_internal_idx_max = 0;
+	media_entity_graph_walk_cleanup(&mdev->pm_count_walk);
 	mutex_destroy(&mdev->graph_mutex);
 }
 EXPORT_SYMBOL_GPL(media_device_cleanup);