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