xn_get_rx_mbuf
m = xn_get_rx_mbuf(rxq, *cons);
m0 = m = m_prev = xn_get_rx_mbuf(rxq, *cons);
m = xn_get_rx_mbuf(rxq, *cons + frags);
m = rxq->mbufs[requeue_idx] = xn_get_rx_mbuf(rxq, i);