RX_SGE_NEXT_PAGE_DESC_CNT
#define RX_SGE_USABLE_PER_PAGE (RX_SGE_TOTAL_PER_PAGE - RX_SGE_NEXT_PAGE_DESC_CNT)
? (x) + 1 + RX_SGE_NEXT_PAGE_DESC_CNT : (x) + 1)
(NUM_SGE_REQ(sc) + NUM_SGE_PG_REQ(sc) * RX_SGE_NEXT_PAGE_DESC_CNT)