diff --git a/drivers/md/bcache/btree.c b/drivers/md/bcache/btree.c
index 3518088d7ff1..de1eb7961fe6 100644
--- a/drivers/md/bcache/btree.c
+++ b/drivers/md/bcache/btree.c
@@ -1008,6 +1008,9 @@ err:
  *
  * The btree node will have either a read or a write lock held, depending on
  * level and op->lock.
+ *
+ * Note: Only error code or btree pointer will be returned, it is unncessary
+ *       for callers to check NULL pointer.
  */
 struct btree *bch_btree_node_get(struct cache_set *c, struct btree_op *op,
 				 struct bkey *k, int level, bool write,
@@ -1120,6 +1123,10 @@ retry:
 	mutex_unlock(&b->c->bucket_lock);
 }
 
+/*
+ * Only error code or btree pointer will be returned, it is unncessary for
+ * callers to check NULL pointer.
+ */
 struct btree *__bch_btree_node_alloc(struct cache_set *c, struct btree_op *op,
 				     int level, bool wait,
 				     struct btree *parent)