IWI_RX_RING_COUNT
sc->rxq.cur = (sc->rxq.cur + 1) % IWI_RX_RING_COUNT;
hw = (hw == 0) ? IWI_RX_RING_COUNT - 1 : hw - 1;
if (iwi_alloc_rx_ring(sc, &sc->rxq, IWI_RX_RING_COUNT) != 0) {