[nrf fromtree] Bluetooth: Mesh: Model extensions walk stops before last

...model

When reaching the last model in the circular extension linked list, the
walker would abandon the walk before checking the last model. This makes
us skip models when checking the subscription list, potentially causing
incoming messages to be wrongfully ignored.

(cherry picked from commit cd89f42)
Signed-off-by: Trond Einar Snekvik <[email protected]>

Author: trond-snekvik

subsys/bluetooth/mesh/access.c

@@ -821,12 +821,12 @@ void bt_mesh_model_extensions_walk(struct bt_mesh_model *model,
 #else
 	struct bt_mesh_model *it;
 
-	if (model->next == NULL) {
-		(void)cb(model, user_data);
+	if (cb(model, user_data) == BT_MESH_WALK_STOP || !model->next) {
 		return;
 	}
 
-	for (it = model; (it != NULL) && (it->next != model); it = it->next) {
+	/* List is circular. Step through all models until we reach the start: */
+	for (it = model->next; it != model; it = it->next) {
 		if (cb(it, user_data) == BT_MESH_WALK_STOP) {
 			return;
 		}