code: func dropDisabledCSIVolumeSourceAlphaFields(podSpec, oldPodSpec *api.PodSpec) {
  	if !utilfeature.DefaultFeatureGate.Enabled(features.CSIInlineVolume) && !csiInUse(oldPodSpec) {
  		for i := range podSpec.Volumes {
  			podSpec.Volumes[i].CSI = nil
  		}
  	}
  }
docs: // dropDisabledCSIVolumeSourceAlphaFields removes disabled alpha fields from []CSIVolumeSource.
  // This should be called from PrepareForCreate/PrepareForUpdate for all pod specs resources containing a CSIVolumeSource