PG_CHAIN_IDX
pg_prod = PG_CHAIN_IDX(pg_prod + 1);
"index\n", sc->pg_prod, (u16) PG_CHAIN_IDX(sc->pg_prod));
"index\n", sc->pg_cons, (u16) PG_CHAIN_IDX(sc->pg_cons));
prod_idx = PG_CHAIN_IDX(prod);
sw_pg_cons_idx = PG_CHAIN_IDX(sw_pg_cons);
chain_prod = PG_CHAIN_IDX(NEXT_PG_BD(chain_prod));