NUM_RX_BD
#define MAX_RX_BD (NUM_RX_BD - 1)
for (i = 0; i < NUM_RX_BD; i++) {
sizeof(struct eth_rx_bd) * NUM_RX_BD);
kzalloc_objs(struct sw_rx_bd, NUM_RX_BD);
sizeof(struct eth_rx_bd) * NUM_RX_BD);