diff --git a/nova/tests/unit/virt/test_virt.py b/nova/tests/unit/virt/test_virt.py
index 3643d189772b..b01df08e535c 100644
--- a/nova/tests/unit/virt/test_virt.py
+++ b/nova/tests/unit/virt/test_virt.py
@@ -49,10 +49,11 @@ class TestVirtDriver(test.NoDBTestCase):
         empty_block_device_info = {}
 
         self.assertEqual(
-            driver.block_device_info_get_root(block_device_info), '/dev/sda')
+            driver.block_device_info_get_root_device(block_device_info),
+            '/dev/sda')
         self.assertIsNone(
-            driver.block_device_info_get_root(empty_block_device_info))
-        self.assertIsNone(driver.block_device_info_get_root(None))
+            driver.block_device_info_get_root_device(empty_block_device_info))
+        self.assertIsNone(driver.block_device_info_get_root_device(None))
 
         self.assertEqual(
             driver.block_device_info_get_swap(block_device_info), swap)
diff --git a/nova/virt/driver.py b/nova/virt/driver.py
index c7f96eabde11..1b80b9ac6417 100644
--- a/nova/virt/driver.py
+++ b/nova/virt/driver.py
@@ -63,7 +63,7 @@ def get_block_device_info(instance, block_device_mapping):
     return block_device_info
 
 
-def block_device_info_get_root(block_device_info):
+def block_device_info_get_root_device(block_device_info):
     block_device_info = block_device_info or {}
     return block_device_info.get('root_device_name')
 
diff --git a/nova/virt/hyperv/block_device_manager.py b/nova/virt/hyperv/block_device_manager.py
index 9ba5a01e87bd..626c87c85686 100644
--- a/nova/virt/hyperv/block_device_manager.py
+++ b/nova/virt/hyperv/block_device_manager.py
@@ -127,8 +127,9 @@ class BlockDeviceInfoManager(object):
         # either booting from volume, or booting from image/iso
         root_disk = {}
 
-        root_device = (driver.block_device_info_get_root(block_device_info) or
-                       self._DEFAULT_ROOT_DEVICE)
+        root_device = driver.block_device_info_get_root_device(
+                block_device_info)
+        root_device = root_device or self._DEFAULT_ROOT_DEVICE
 
         if self.is_boot_from_volume(block_device_info):
             root_volume = self._get_root_device_bdm(
diff --git a/nova/virt/libvirt/blockinfo.py b/nova/virt/libvirt/blockinfo.py
index ac11e26563c9..0dfea1c19c67 100644
--- a/nova/virt/libvirt/blockinfo.py
+++ b/nova/virt/libvirt/blockinfo.py
@@ -550,7 +550,7 @@ def get_disk_mapping(virt_type, instance,
         driver.block_device_info_get_mapping(block_device_info))
 
     root_device_name = block_device.strip_dev(
-        driver.block_device_info_get_root(block_device_info))
+        driver.block_device_info_get_root_device(block_device_info))
     root_info = get_root_info(
         instance, virt_type, image_meta, root_bdm,
         disk_bus, cdrom_bus, root_device_name)