SFXGE_TX_MAPPING_MAX_SEG
if_sethwtsomaxsegcount(ifp, SFXGE_TX_MAPPING_MAX_SEG);
unsigned int max_descs = SFXGE_TX_MAPPING_MAX_SEG;
howmany(SFXGE_TX_MAPPING_MAX_SEG,
NULL, 0x11000, SFXGE_TX_MAPPING_MAX_SEG,
bus_dma_segment_t dma_seg[SFXGE_TX_MAPPING_MAX_SEG];
SFXGE_TX_MAPPING_MAX_SEG);