mmc_post_req
mmc_post_req(host, &mqrq->brq.mrq, err);
mmc_post_req(host, mrq, 0);
mmc_post_req(host, &mqrq->brq.mrq, err);
mmc_post_req(host, prev_mrq, 0);
mmc_post_req(host, mrq, err);
mmc_post_req(card->host, &mrq, err);