generic ephemeral volume: graduation to GA

The feature gate gets locked to "true", with the goal to remove it in two
releases.

All code now can assume that the feature is enabled. Tests for "feature
disabled" are no longer needed and get removed.

Some code wasn't using the new helper functions yet. That gets changed while
touching those lines.

pkg/scheduler/framework/plugins/nodevolumelimits/csi.go

@@ -56,8 +56,6 @@ type CSILimits struct {
 	randomVolumeIDPrefix string
 
 	translator InTreeToCSITranslator
-
-	enableGenericEphemeralVolume bool
 }
 
 var _ framework.FilterPlugin = &CSILimits{}
@@ -157,12 +155,6 @@ func (pl *CSILimits) filterAttachableVolumes(
 		case vol.PersistentVolumeClaim != nil:
 			pvcName = vol.PersistentVolumeClaim.ClaimName
 		case vol.Ephemeral != nil:
-			if newPod && !pl.enableGenericEphemeralVolume {
-				return fmt.Errorf(
-					"volume %s is a generic ephemeral volume, but that feature is disabled in kube-scheduler",
-					vol.Name,
-				)
-			}
 			// Generic ephemeral inline volumes also use a PVC,
 			// just with a computed name and certain ownership.
 			// That is checked below once the pvc object is
@@ -320,13 +312,12 @@ func NewCSI(_ runtime.Object, handle framework.Handle, fts feature.Features) (fr
 	scLister := informerFactory.Storage().V1().StorageClasses().Lister()
 
 	return &CSILimits{
-		csiNodeLister:                csiNodesLister,
-		pvLister:                     pvLister,
-		pvcLister:                    pvcLister,
-		scLister:                     scLister,
-		randomVolumeIDPrefix:         rand.String(32),
-		translator:                   csitrans.New(),
-		enableGenericEphemeralVolume: fts.EnableGenericEphemeralVolume,
+		csiNodeLister:        csiNodesLister,
+		pvLister:             pvLister,
+		pvcLister:            pvcLister,
+		scLister:             scLister,
+		randomVolumeIDPrefix: rand.String(32),
+		translator:           csitrans.New(),
 	}, nil
 }