RX_NUM_DESC
r->r_avail_desc = RX_NUM_DESC;
slot %= RX_NUM_DESC;
if (slot == (RX_NUM_DESC - 1))
BFE_INC_SLOT(i, RX_NUM_DESC)) {
bfe->bfe_rx_ring.r_ndesc = RX_NUM_DESC;
bfe->bfe_rx_ring.r_avail_desc = RX_NUM_DESC;