RX_DESC_RING_SIZE
#define RX_DESC_RINGN_SIZE(x) RX_DESC_RING_SIZE
#define INIT_BLOCK_RX_DESC (RX_DESC_RING_SIZE)
cas_page_t *rx_pages[N_RX_DESC_RINGS][RX_DESC_RING_SIZE];
#define RX_SPARE_COUNT (RX_DESC_RING_SIZE >> 1)