dl_info_ack_wrapper_t
dl_info_ack_wrapper_t *dlwp;
if ((mp = mexchange(q, mp, sizeof (dl_info_ack_wrapper_t),
bzero(mp->b_rptr, sizeof (dl_info_ack_wrapper_t));
dlwp = (dl_info_ack_wrapper_t *)mp->b_rptr;