EF4_TX_CB_ORDER
#define EF4_TX_CB_SIZE (1 << EF4_TX_CB_ORDER) - NET_IP_ALIGN
&tx_queue->cb_page[index >> (PAGE_SHIFT - EF4_TX_CB_ORDER)];
((index << EF4_TX_CB_ORDER) + NET_IP_ALIGN) & (PAGE_SIZE - 1);
return DIV_ROUND_UP(tx_queue->ptr_mask + 1, PAGE_SIZE >> EF4_TX_CB_ORDER);