sg_set_buf(&sg[0], buf, buflen);
if (sg[0].offset + buflen > PAGE_SIZE) {
/* the buffer was split over two pages */
sg[0].length = PAGE_SIZE - sg[0].offset;
sg_set_buf(&sg[1], buf + sg[0].length, buflen - sg[0].length);
sg_set_buf(&sg[0], buf, buflen);
if (sg[0].offset + buflen > PAGE_SIZE) {
/* the buffer was split over two pages */
sg[0].length = PAGE_SIZE - sg[0].offset;
sg_set_buf(&sg[1], buf + sg[0].length, buflen - sg[0].length);