res = st_map_user_pages(schp->buffer, mx_sc_elems,
(unsigned long)hp->dxferp, dxfer_len,
(SG_DXFER_TO_DEV == hp->dxfer_direction) ? 1 : 0);
res = st_map_user_pages(schp->buffer, mx_sc_elems,
(unsigned long)hp->dxferp, dxfer_len,
(SG_DXFER_TO_DEV == hp->dxfer_direction) ? 1 : 0);