diff --git a/driver/controller.go b/driver/controller.go
index 01ffcee..5cec80c 100644
--- a/driver/controller.go
+++ b/driver/controller.go
@@ -780,11 +780,6 @@ func (d *controllerService) ControllerGetVolume(ctx context.Context, req *csi.Co
 	}, nil
 }
 
-func (d *controllerService) ControllerModifyVolume(context.Context, *csi.ControllerModifyVolumeRequest) (*csi.ControllerModifyVolumeResponse, error) {
-
-	return nil, nil
-}
-
 func newClientZone(ctx context.Context, c *v3.Client, z v3.ZoneName) (*v3.Client, error) {
 	endpoint, err := c.GetZoneAPIEndpoint(ctx, z)
 	if err != nil {
diff --git a/driver/helpers.go b/driver/helpers.go
index 3f2beaf..d05884d 100644
--- a/driver/helpers.go
+++ b/driver/helpers.go
@@ -46,8 +46,8 @@ func validateVolumeCapability(volumeCapability *csi.VolumeCapability) error {
 	if volumeCapability == nil {
 		return fmt.Errorf("volumeCapability is nil")
 	}
-	for _, accessMode := range supportedAccessModes {
-		if accessMode.Mode == volumeCapability.GetAccessMode().GetMode() {
+	for i := range supportedAccessModes {
+		if supportedAccessModes[i].Mode == volumeCapability.GetAccessMode().GetMode() {
 			return nil
 		}
 	}