adwexecuteacb
adwexecuteacb,
adwexecuteacb(acb, &seg, 1, 0);
adwexecuteacb(acb, segs, csio->sglist_cnt,
adwexecuteacb(acb, NULL, 0, 0);
static void adwexecuteacb(void *arg, bus_dma_segment_t *dm_segs,