struct scatterlist {
	void *page;
	int offset;
};
void mmc_blk_issue_rq()
{
	int blocks;
	struct scatterlist sg;
	void *buf = &blocks;
	memset(&sg, 0, sizeof(sg));
	sg.page = (unsigned long)buf - 0x80000000 >> 12;
	sg.offset = (unsigned long)buf & 1 << 12;
	if (blocks)
		foo();
}