MVXPE_RX_PKTBUF
MVXPE_RX_PKTBUF(sc, q, i) = NULL;
if (MVXPE_RX_PKTBUF(sc, q, i) == NULL)
mvxpbm_free_chunk(MVXPE_RX_PKTBUF(sc, q, i));
MVXPE_RX_PKTBUF(sc, q, i) = NULL;
chunk = MVXPE_RX_PKTBUF(sc, q, rx->rx_dma);
MVXPE_RX_PKTBUF(sc, q, rx->rx_dma) = NULL;
KASSERT(MVXPE_RX_PKTBUF(sc, q, rx->rx_cpu) == NULL);
MVXPE_RX_PKTBUF(sc, q, rx->rx_cpu) = chunk;