VDSK_RX_ENTRIES
lc->lc_rxq = ldc_queue_alloc(sc->sc_dmatag, VDSK_RX_ENTRIES);
sc->sc_desc_tail &= (VDSK_RX_ENTRIES - 1);
struct vdsk_desc_msg *sc_desc_msg[VDSK_RX_ENTRIES];
lc->lc_rxq = ldc_queue_alloc(sc->sc_dmatag, VDSK_RX_ENTRIES);
sc->sc_desc_head &= (VDSK_RX_ENTRIES - 1);