e1000_adv_tx_desc
size = sizeof (union e1000_adv_tx_desc) * tx_ring->ring_size;
size += sizeof (union e1000_adv_tx_desc);
tx_ring->tbd_ring = (union e1000_adv_tx_desc *)(uintptr_t)
size = tx_ring->ring_size * sizeof (union e1000_adv_tx_desc);
union e1000_adv_tx_desc *tbd_ring;
sizeof (union e1000_adv_tx_desc) * tx_ring->ring_size,
union e1000_adv_tx_desc *tbd, *first_tbd;