VTSCSI_FROZEN_NO_REQUESTS
(sc->vtscsi_frozen & VTSCSI_FROZEN_NO_REQUESTS) == 0)
sc->vtscsi_frozen |= VTSCSI_FROZEN_NO_REQUESTS;
sc->vtscsi_frozen & VTSCSI_FROZEN_NO_REQUESTS)
sc->vtscsi_frozen &= ~VTSCSI_FROZEN_NO_REQUESTS;