diff --git a/cinder/volume/driver.py b/cinder/volume/driver.py
index b015eebf06c..0c1ba69526b 100644
--- a/cinder/volume/driver.py
+++ b/cinder/volume/driver.py
@@ -1821,6 +1821,7 @@ class ManageableVD(object):
         :param volume:       Cinder volume to manage
         :param existing_ref: Driver-specific information used to identify a
                              volume
+        :returns size:       Volume size in GiB (integer)
         """
         return