ivtv_udma_fill_sg_list
if (ivtv_udma_fill_sg_list(dma, &user_dma, 0) < 0) {
int ivtv_udma_fill_sg_list(struct ivtv_user_dma *dma, struct ivtv_dma_page_info *dma_page, int map_offset);
if (ivtv_udma_fill_sg_list (dma, &uv_dma, ivtv_udma_fill_sg_list (dma, &y_dma, 0)) < 0) {