[media] media: entity: Split graph walk iteration into two functions

With media_entity_graph_walk_next() getting more and more complicated (and
especially so with has_routing() support added), split the function into
two.
Signed-off-by: Sakari Ailus <sakari.ailus@linux.intel.com>
Reviewed-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
Signed-off-by: Mauro Carvalho Chehab <mchehab@s-opensource.com>

drivers/media/media-entity.c

@@ -324,17 +324,8 @@ void media_graph_walk_start(struct media_graph *graph,
 }
 EXPORT_SYMBOL_GPL(media_graph_walk_start);
 
-struct media_entity *media_graph_walk_next(struct media_graph *graph)
+static void media_graph_walk_iter(struct media_graph *graph)
 {
-	if (stack_top(graph) == NULL)
-		return NULL;
-
-	/*
-	 * Depth first search. Push entity to stack and continue from
-	 * top of the stack until no more entities on the level can be
-	 * found.
-	 */
-	while (link_top(graph) != &stack_top(graph)->links) {
 	struct media_entity *entity = stack_top(graph);
 	struct media_link *link;
 	struct media_entity *next;
@@ -344,7 +335,7 @@ struct media_entity *media_graph_walk_next(struct media_graph *graph)
 	/* The link is not enabled so we do not follow. */
 	if (!(link->flags & MEDIA_LNK_FL_ENABLED)) {
 		link_top(graph) = link_top(graph)->next;
-			continue;
+		return;
 	}
 
 	/* Get the entity in the other end of the link . */
@@ -353,13 +344,26 @@ struct media_entity *media_graph_walk_next(struct media_graph *graph)
 	/* Has the entity already been visited? */
 	if (media_entity_enum_test_and_set(&graph->ent_enum, next)) {
 		link_top(graph) = link_top(graph)->next;
-			continue;
+		return;
 	}
 
 	/* Push the new entity to stack and start over. */
 	link_top(graph) = link_top(graph)->next;
 	stack_push(graph, next);
-	}
+}
+
+struct media_entity *media_graph_walk_next(struct media_graph *graph)
+{
+	if (stack_top(graph) == NULL)
+		return NULL;
+
+	/*
+	 * Depth first search. Push entity to stack and continue from
+	 * top of the stack until no more entities on the level can be
+	 * found.
+	 */
+	while (link_top(graph) != &stack_top(graph)->links)
+		media_graph_walk_iter(graph);
 
 	return stack_pop(graph);
 }