#define INAND_CMD38_ARG_SECTRIM2 0x88
#define MMC_BLK_TIMEOUT_MS (10 * 60 * 1000) /* 10 minute timeout */
+#define mmc_req_rel_wr(req) (((req->cmd_flags & REQ_FUA) || \
+ (req->cmd_flags & REQ_META)) && \
+ (rq_data_dir(req) == WRITE))
+#define PACKED_CMD_VER 0x01
+#define PACKED_CMD_WR 0x02
+
static DEFINE_MUTEX(block_mutex);
/*
unsigned int flags;
#define MMC_BLK_CMD23 (1 << 0) /* Can do SET_BLOCK_COUNT for multiblock */
#define MMC_BLK_REL_WR (1 << 1) /* MMC Reliable write support */
+#define MMC_BLK_PACKED_CMD (1 << 2) /* MMC packed command support */
unsigned int usage;
unsigned int read_only;
static DEFINE_MUTEX(open_lock);
+enum {
+ MMC_PACKED_NR_IDX = -1,
+ MMC_PACKED_NR_ZERO,
+ MMC_PACKED_NR_SINGLE,
+};
+
module_param(perdev_minors, int, 0444);
MODULE_PARM_DESC(perdev_minors, "Minors numbers to allocate per device");
struct mmc_blk_data *md);
static int get_card_status(struct mmc_card *card, u32 *status, int retries);
+static inline void mmc_blk_clear_packed(struct mmc_queue_req *mqrq)
+{
+ struct mmc_packed *packed = mqrq->packed;
+
+ BUG_ON(!packed);
+
+ mqrq->cmd_type = MMC_PACKED_NONE;
+ packed->nr_entries = MMC_PACKED_NR_ZERO;
+ packed->idx_failure = MMC_PACKED_NR_IDX;
+ packed->retries = 0;
+ packed->blocks = 0;
+}
+
static struct mmc_blk_data *mmc_blk_get(struct gendisk *disk)
{
struct mmc_blk_data *md;
if (!brq->data.bytes_xfered)
return MMC_BLK_RETRY;
+ if (mmc_packed_cmd(mq_mrq->cmd_type)) {
+ if (unlikely(brq->data.blocks << 9 != brq->data.bytes_xfered))
+ return MMC_BLK_PARTIAL;
+ else
+ return MMC_BLK_SUCCESS;
+ }
+
if (blk_rq_bytes(req) != brq->data.bytes_xfered)
return MMC_BLK_PARTIAL;
return MMC_BLK_SUCCESS;
}
+static int mmc_blk_packed_err_check(struct mmc_card *card,
+ struct mmc_async_req *areq)
+{
+ struct mmc_queue_req *mq_rq = container_of(areq, struct mmc_queue_req,
+ mmc_active);
+ struct request *req = mq_rq->req;
+ struct mmc_packed *packed = mq_rq->packed;
+ int err, check, status;
+ u8 *ext_csd;
+
+ BUG_ON(!packed);
+
+ packed->retries--;
+ check = mmc_blk_err_check(card, areq);
+ err = get_card_status(card, &status, 0);
+ if (err) {
+ pr_err("%s: error %d sending status command\n",
+ req->rq_disk->disk_name, err);
+ return MMC_BLK_ABORT;
+ }
+
+ if (status & R1_EXCEPTION_EVENT) {
+ ext_csd = kzalloc(512, GFP_KERNEL);
+ if (!ext_csd) {
+ pr_err("%s: unable to allocate buffer for ext_csd\n",
+ req->rq_disk->disk_name);
+ return -ENOMEM;
+ }
+
+ err = mmc_send_ext_csd(card, ext_csd);
+ if (err) {
+ pr_err("%s: error %d sending ext_csd\n",
+ req->rq_disk->disk_name, err);
+ check = MMC_BLK_ABORT;
+ goto free;
+ }
+
+ if ((ext_csd[EXT_CSD_EXP_EVENTS_STATUS] &
+ EXT_CSD_PACKED_FAILURE) &&
+ (ext_csd[EXT_CSD_PACKED_CMD_STATUS] &
+ EXT_CSD_PACKED_GENERIC_ERROR)) {
+ if (ext_csd[EXT_CSD_PACKED_CMD_STATUS] &
+ EXT_CSD_PACKED_INDEXED_ERROR) {
+ packed->idx_failure =
+ ext_csd[EXT_CSD_PACKED_FAILURE_INDEX] - 1;
+ check = MMC_BLK_PARTIAL;
+ }
+ pr_err("%s: packed cmd failed, nr %u, sectors %u, "
+ "failure index: %d\n",
+ req->rq_disk->disk_name, packed->nr_entries,
+ packed->blocks, packed->idx_failure);
+ }
+free:
+ kfree(ext_csd);
+ }
+
+ return check;
+}
+
static void mmc_blk_rw_rq_prep(struct mmc_queue_req *mqrq,
struct mmc_card *card,
int disable_multi,
mmc_queue_bounce_pre(mqrq);
}
+static inline u8 mmc_calc_packed_hdr_segs(struct request_queue *q,
+ struct mmc_card *card)
+{
+ unsigned int hdr_sz = mmc_large_sector(card) ? 4096 : 512;
+ unsigned int max_seg_sz = queue_max_segment_size(q);
+ unsigned int len, nr_segs = 0;
+
+ do {
+ len = min(hdr_sz, max_seg_sz);
+ hdr_sz -= len;
+ nr_segs++;
+ } while (hdr_sz);
+
+ return nr_segs;
+}
+
+static u8 mmc_blk_prep_packed_list(struct mmc_queue *mq, struct request *req)
+{
+ struct request_queue *q = mq->queue;
+ struct mmc_card *card = mq->card;
+ struct request *cur = req, *next = NULL;
+ struct mmc_blk_data *md = mq->data;
+ struct mmc_queue_req *mqrq = mq->mqrq_cur;
+ bool en_rel_wr = card->ext_csd.rel_param & EXT_CSD_WR_REL_PARAM_EN;
+ unsigned int req_sectors = 0, phys_segments = 0;
+ unsigned int max_blk_count, max_phys_segs;
+ bool put_back = true;
+ u8 max_packed_rw = 0;
+ u8 reqs = 0;
+
+ if (!(md->flags & MMC_BLK_PACKED_CMD))
+ goto no_packed;
+
+ if ((rq_data_dir(cur) == WRITE) &&
+ mmc_host_packed_wr(card->host))
+ max_packed_rw = card->ext_csd.max_packed_writes;
+
+ if (max_packed_rw == 0)
+ goto no_packed;
+
+ if (mmc_req_rel_wr(cur) &&
+ (md->flags & MMC_BLK_REL_WR) && !en_rel_wr)
+ goto no_packed;
+
+ if (mmc_large_sector(card) &&
+ !IS_ALIGNED(blk_rq_sectors(cur), 8))
+ goto no_packed;
+
+ mmc_blk_clear_packed(mqrq);
+
+ max_blk_count = min(card->host->max_blk_count,
+ card->host->max_req_size >> 9);
+ if (unlikely(max_blk_count > 0xffff))
+ max_blk_count = 0xffff;
+
+ max_phys_segs = queue_max_segments(q);
+ req_sectors += blk_rq_sectors(cur);
+ phys_segments += cur->nr_phys_segments;
+
+ if (rq_data_dir(cur) == WRITE) {
+ req_sectors += mmc_large_sector(card) ? 8 : 1;
+ phys_segments += mmc_calc_packed_hdr_segs(q, card);
+ }
+
+ do {
+ if (reqs >= max_packed_rw - 1) {
+ put_back = false;
+ break;
+ }
+
+ spin_lock_irq(q->queue_lock);
+ next = blk_fetch_request(q);
+ spin_unlock_irq(q->queue_lock);
+ if (!next) {
+ put_back = false;
+ break;
+ }
+
+ if (mmc_large_sector(card) &&
+ !IS_ALIGNED(blk_rq_sectors(next), 8))
+ break;
+
+ if (next->cmd_flags & REQ_DISCARD ||
+ next->cmd_flags & REQ_FLUSH)
+ break;
+
+ if (rq_data_dir(cur) != rq_data_dir(next))
+ break;
+
+ if (mmc_req_rel_wr(next) &&
+ (md->flags & MMC_BLK_REL_WR) && !en_rel_wr)
+ break;
+
+ req_sectors += blk_rq_sectors(next);
+ if (req_sectors > max_blk_count)
+ break;
+
+ phys_segments += next->nr_phys_segments;
+ if (phys_segments > max_phys_segs)
+ break;
+
+ list_add_tail(&next->queuelist, &mqrq->packed->list);
+ cur = next;
+ reqs++;
+ } while (1);
+
+ if (put_back) {
+ spin_lock_irq(q->queue_lock);
+ blk_requeue_request(q, next);
+ spin_unlock_irq(q->queue_lock);
+ }
+
+ if (reqs > 0) {
+ list_add(&req->queuelist, &mqrq->packed->list);
+ mqrq->packed->nr_entries = ++reqs;
+ mqrq->packed->retries = reqs;
+ return reqs;
+ }
+
+no_packed:
+ mqrq->cmd_type = MMC_PACKED_NONE;
+ return 0;
+}
+
+static void mmc_blk_packed_hdr_wrq_prep(struct mmc_queue_req *mqrq,
+ struct mmc_card *card,
+ struct mmc_queue *mq)
+{
+ struct mmc_blk_request *brq = &mqrq->brq;
+ struct request *req = mqrq->req;
+ struct request *prq;
+ struct mmc_blk_data *md = mq->data;
+ struct mmc_packed *packed = mqrq->packed;
+ bool do_rel_wr, do_data_tag;
+ u32 *packed_cmd_hdr;
+ u8 hdr_blocks;
+ u8 i = 1;
+
+ BUG_ON(!packed);
+
+ mqrq->cmd_type = MMC_PACKED_WRITE;
+ packed->blocks = 0;
+ packed->idx_failure = MMC_PACKED_NR_IDX;
+
+ packed_cmd_hdr = packed->cmd_hdr;
+ memset(packed_cmd_hdr, 0, sizeof(packed->cmd_hdr));
+ packed_cmd_hdr[0] = (packed->nr_entries << 16) |
+ (PACKED_CMD_WR << 8) | PACKED_CMD_VER;
+ hdr_blocks = mmc_large_sector(card) ? 8 : 1;
+
+ /*
+ * Argument for each entry of packed group
+ */
+ list_for_each_entry(prq, &packed->list, queuelist) {
+ do_rel_wr = mmc_req_rel_wr(prq) && (md->flags & MMC_BLK_REL_WR);
+ do_data_tag = (card->ext_csd.data_tag_unit_size) &&
+ (prq->cmd_flags & REQ_META) &&
+ (rq_data_dir(prq) == WRITE) &&
+ ((brq->data.blocks * brq->data.blksz) >=
+ card->ext_csd.data_tag_unit_size);
+ /* Argument of CMD23 */
+ packed_cmd_hdr[(i * 2)] =
+ (do_rel_wr ? MMC_CMD23_ARG_REL_WR : 0) |
+ (do_data_tag ? MMC_CMD23_ARG_TAG_REQ : 0) |
+ blk_rq_sectors(prq);
+ /* Argument of CMD18 or CMD25 */
+ packed_cmd_hdr[((i * 2)) + 1] =
+ mmc_card_blockaddr(card) ?
+ blk_rq_pos(prq) : blk_rq_pos(prq) << 9;
+ packed->blocks += blk_rq_sectors(prq);
+ i++;
+ }
+
+ memset(brq, 0, sizeof(struct mmc_blk_request));
+ brq->mrq.cmd = &brq->cmd;
+ brq->mrq.data = &brq->data;
+ brq->mrq.sbc = &brq->sbc;
+ brq->mrq.stop = &brq->stop;
+
+ brq->sbc.opcode = MMC_SET_BLOCK_COUNT;
+ brq->sbc.arg = MMC_CMD23_ARG_PACKED | (packed->blocks + hdr_blocks);
+ brq->sbc.flags = MMC_RSP_R1 | MMC_CMD_AC;
+
+ brq->cmd.opcode = MMC_WRITE_MULTIPLE_BLOCK;
+ brq->cmd.arg = blk_rq_pos(req);
+ if (!mmc_card_blockaddr(card))
+ brq->cmd.arg <<= 9;
+ brq->cmd.flags = MMC_RSP_SPI_R1 | MMC_RSP_R1 | MMC_CMD_ADTC;
+
+ brq->data.blksz = 512;
+ brq->data.blocks = packed->blocks + hdr_blocks;
+ brq->data.flags |= MMC_DATA_WRITE;
+
+ brq->stop.opcode = MMC_STOP_TRANSMISSION;
+ brq->stop.arg = 0;
+ brq->stop.flags = MMC_RSP_SPI_R1B | MMC_RSP_R1B | MMC_CMD_AC;
+
+ mmc_set_data_timeout(&brq->data, card);
+
+ brq->data.sg = mqrq->sg;
+ brq->data.sg_len = mmc_queue_map_sg(mq, mqrq);
+
+ mqrq->mmc_active.mrq = &brq->mrq;
+ mqrq->mmc_active.err_check = mmc_blk_packed_err_check;
+
+ mmc_queue_bounce_pre(mqrq);
+}
+
static int mmc_blk_cmd_err(struct mmc_blk_data *md, struct mmc_card *card,
struct mmc_blk_request *brq, struct request *req,
int ret)
{
+ struct mmc_queue_req *mq_rq;
+ mq_rq = container_of(brq, struct mmc_queue_req, brq);
+
/*
* If this is an SD card and we're writing, we can first
* mark the known good sectors as ok.
ret = blk_end_request(req, 0, blocks << 9);
}
} else {
- ret = blk_end_request(req, 0, brq->data.bytes_xfered);
+ if (!mmc_packed_cmd(mq_rq->cmd_type))
+ ret = blk_end_request(req, 0, brq->data.bytes_xfered);
}
return ret;
}
+static int mmc_blk_end_packed_req(struct mmc_queue_req *mq_rq)
+{
+ struct request *prq;
+ struct mmc_packed *packed = mq_rq->packed;
+ int idx = packed->idx_failure, i = 0;
+ int ret = 0;
+
+ BUG_ON(!packed);
+
+ while (!list_empty(&packed->list)) {
+ prq = list_entry_rq(packed->list.next);
+ if (idx == i) {
+ /* retry from error index */
+ packed->nr_entries -= idx;
+ mq_rq->req = prq;
+ ret = 1;
+
+ if (packed->nr_entries == MMC_PACKED_NR_SINGLE) {
+ list_del_init(&prq->queuelist);
+ mmc_blk_clear_packed(mq_rq);
+ }
+ return ret;
+ }
+ list_del_init(&prq->queuelist);
+ blk_end_request(prq, 0, blk_rq_bytes(prq));
+ i++;
+ }
+
+ mmc_blk_clear_packed(mq_rq);
+ return ret;
+}
+
+static void mmc_blk_abort_packed_req(struct mmc_queue_req *mq_rq)
+{
+ struct request *prq;
+ struct mmc_packed *packed = mq_rq->packed;
+
+ BUG_ON(!packed);
+
+ while (!list_empty(&packed->list)) {
+ prq = list_entry_rq(packed->list.next);
+ list_del_init(&prq->queuelist);
+ blk_end_request(prq, -EIO, blk_rq_bytes(prq));
+ }
+
+ mmc_blk_clear_packed(mq_rq);
+}
+
+static void mmc_blk_revert_packed_req(struct mmc_queue *mq,
+ struct mmc_queue_req *mq_rq)
+{
+ struct request *prq;
+ struct request_queue *q = mq->queue;
+ struct mmc_packed *packed = mq_rq->packed;
+
+ BUG_ON(!packed);
+
+ while (!list_empty(&packed->list)) {
+ prq = list_entry_rq(packed->list.prev);
+ if (prq->queuelist.prev != &packed->list) {
+ list_del_init(&prq->queuelist);
+ spin_lock_irq(q->queue_lock);
+ blk_requeue_request(mq->queue, prq);
+ spin_unlock_irq(q->queue_lock);
+ } else {
+ list_del_init(&prq->queuelist);
+ }
+ }
+
+ mmc_blk_clear_packed(mq_rq);
+}
+
static int mmc_blk_issue_rw_rq(struct mmc_queue *mq, struct request *rqc)
{
struct mmc_blk_data *md = mq->data;
struct mmc_queue_req *mq_rq;
struct request *req = rqc;
struct mmc_async_req *areq;
+ const u8 packed_nr = 2;
+ u8 reqs = 0;
if (!rqc && !mq->mqrq_prev->req)
return 0;
+ if (rqc)
+ reqs = mmc_blk_prep_packed_list(mq, rqc);
+
do {
if (rqc) {
/*
(card->ext_csd.data_sector_size == 4096)) {
pr_err("%s: Transfer size is not 4KB sector size aligned\n",
req->rq_disk->disk_name);
+ mq_rq = mq->mqrq_cur;
goto cmd_abort;
}
- mmc_blk_rw_rq_prep(mq->mqrq_cur, card, 0, mq);
+
+ if (reqs >= packed_nr)
+ mmc_blk_packed_hdr_wrq_prep(mq->mqrq_cur,
+ card, mq);
+ else
+ mmc_blk_rw_rq_prep(mq->mqrq_cur, card, 0, mq);
areq = &mq->mqrq_cur->mmc_active;
} else
areq = NULL;
* A block was successfully transferred.
*/
mmc_blk_reset_success(md, type);
- ret = blk_end_request(req, 0,
+
+ if (mmc_packed_cmd(mq_rq->cmd_type)) {
+ ret = mmc_blk_end_packed_req(mq_rq);
+ break;
+ } else {
+ ret = blk_end_request(req, 0,
brq->data.bytes_xfered);
+ }
+
/*
* If the blk_end_request function returns non-zero even
* though all data has been transferred and no errors
err = mmc_blk_reset(md, card->host, type);
if (!err)
break;
- if (err == -ENODEV)
+ if (err == -ENODEV ||
+ mmc_packed_cmd(mq_rq->cmd_type))
goto cmd_abort;
/* Fall through */
}
}
if (ret) {
- /*
- * In case of a incomplete request
- * prepare it again and resend.
- */
- mmc_blk_rw_rq_prep(mq_rq, card, disable_multi, mq);
- mmc_start_req(card->host, &mq_rq->mmc_active, NULL);
+ if (mmc_packed_cmd(mq_rq->cmd_type)) {
+ if (!mq_rq->packed->retries)
+ goto cmd_abort;
+ mmc_blk_packed_hdr_wrq_prep(mq_rq, card, mq);
+ mmc_start_req(card->host,
+ &mq_rq->mmc_active, NULL);
+ } else {
+
+ /*
+ * In case of a incomplete request
+ * prepare it again and resend.
+ */
+ mmc_blk_rw_rq_prep(mq_rq, card,
+ disable_multi, mq);
+ mmc_start_req(card->host,
+ &mq_rq->mmc_active, NULL);
+ }
}
} while (ret);
return 1;
cmd_abort:
- if (mmc_card_removed(card))
- req->cmd_flags |= REQ_QUIET;
- while (ret)
- ret = blk_end_request(req, -EIO, blk_rq_cur_bytes(req));
+ if (mmc_packed_cmd(mq_rq->cmd_type)) {
+ mmc_blk_abort_packed_req(mq_rq);
+ } else {
+ if (mmc_card_removed(card))
+ req->cmd_flags |= REQ_QUIET;
+ while (ret)
+ ret = blk_end_request(req, -EIO,
+ blk_rq_cur_bytes(req));
+ }
start_new_req:
if (rqc) {
rqc->cmd_flags |= REQ_QUIET;
blk_end_request_all(rqc, -EIO);
} else {
+ /*
+ * If current request is packed, it needs to put back.
+ */
+ if (mmc_packed_cmd(mq->mqrq_cur->cmd_type))
+ mmc_blk_revert_packed_req(mq, mq->mqrq_cur);
+
mmc_blk_rw_rq_prep(mq->mqrq_cur, card, 0, mq);
mmc_start_req(card->host,
&mq->mqrq_cur->mmc_active, NULL);
blk_queue_flush(md->queue.queue, REQ_FLUSH | REQ_FUA);
}
+ if (mmc_card_mmc(card) &&
+ (area_type == MMC_BLK_DATA_AREA_MAIN) &&
+ (md->flags & MMC_BLK_CMD23) &&
+ card->ext_csd.packed_event_en) {
+ if (!mmc_packed_init(&md->queue, card))
+ md->flags |= MMC_BLK_PACKED_CMD;
+ }
+
return md;
err_putdisk:
/* Then flush out any already in there */
mmc_cleanup_queue(&md->queue);
+ if (md->flags & MMC_BLK_PACKED_CMD)
+ mmc_packed_clean(&md->queue);
mmc_blk_put(md);
}
}
}
EXPORT_SYMBOL(mmc_cleanup_queue);
+int mmc_packed_init(struct mmc_queue *mq, struct mmc_card *card)
+{
+ struct mmc_queue_req *mqrq_cur = &mq->mqrq[0];
+ struct mmc_queue_req *mqrq_prev = &mq->mqrq[1];
+ int ret = 0;
+
+
+ mqrq_cur->packed = kzalloc(sizeof(struct mmc_packed), GFP_KERNEL);
+ if (!mqrq_cur->packed) {
+ pr_warn("%s: unable to allocate packed cmd for mqrq_cur\n",
+ mmc_card_name(card));
+ ret = -ENOMEM;
+ goto out;
+ }
+
+ mqrq_prev->packed = kzalloc(sizeof(struct mmc_packed), GFP_KERNEL);
+ if (!mqrq_prev->packed) {
+ pr_warn("%s: unable to allocate packed cmd for mqrq_prev\n",
+ mmc_card_name(card));
+ kfree(mqrq_cur->packed);
+ mqrq_cur->packed = NULL;
+ ret = -ENOMEM;
+ goto out;
+ }
+
+ INIT_LIST_HEAD(&mqrq_cur->packed->list);
+ INIT_LIST_HEAD(&mqrq_prev->packed->list);
+
+out:
+ return ret;
+}
+
+void mmc_packed_clean(struct mmc_queue *mq)
+{
+ struct mmc_queue_req *mqrq_cur = &mq->mqrq[0];
+ struct mmc_queue_req *mqrq_prev = &mq->mqrq[1];
+
+ kfree(mqrq_cur->packed);
+ mqrq_cur->packed = NULL;
+ kfree(mqrq_prev->packed);
+ mqrq_prev->packed = NULL;
+}
+
/**
* mmc_queue_suspend - suspend a MMC request queue
* @mq: MMC queue to suspend
}
}
+static unsigned int mmc_queue_packed_map_sg(struct mmc_queue *mq,
+ struct mmc_packed *packed,
+ struct scatterlist *sg,
+ enum mmc_packed_type cmd_type)
+{
+ struct scatterlist *__sg = sg;
+ unsigned int sg_len = 0;
+ struct request *req;
+
+ if (mmc_packed_wr(cmd_type)) {
+ unsigned int hdr_sz = mmc_large_sector(mq->card) ? 4096 : 512;
+ unsigned int max_seg_sz = queue_max_segment_size(mq->queue);
+ unsigned int len, remain, offset = 0;
+ u8 *buf = (u8 *)packed->cmd_hdr;
+
+ remain = hdr_sz;
+ do {
+ len = min(remain, max_seg_sz);
+ sg_set_buf(__sg, buf + offset, len);
+ offset += len;
+ remain -= len;
+ (__sg++)->page_link &= ~0x02;
+ sg_len++;
+ } while (remain);
+ }
+
+ list_for_each_entry(req, &packed->list, queuelist) {
+ sg_len += blk_rq_map_sg(mq->queue, req, __sg);
+ __sg = sg + (sg_len - 1);
+ (__sg++)->page_link &= ~0x02;
+ }
+ sg_mark_end(sg + (sg_len - 1));
+ return sg_len;
+}
+
/*
* Prepare the sg list(s) to be handed of to the host driver
*/
unsigned int sg_len;
size_t buflen;
struct scatterlist *sg;
+ enum mmc_packed_type cmd_type;
int i;
- if (!mqrq->bounce_buf)
- return blk_rq_map_sg(mq->queue, mqrq->req, mqrq->sg);
+ cmd_type = mqrq->cmd_type;
+
+ if (!mqrq->bounce_buf) {
+ if (mmc_packed_cmd(cmd_type))
+ return mmc_queue_packed_map_sg(mq, mqrq->packed,
+ mqrq->sg, cmd_type);
+ else
+ return blk_rq_map_sg(mq->queue, mqrq->req, mqrq->sg);
+ }
BUG_ON(!mqrq->bounce_sg);
- sg_len = blk_rq_map_sg(mq->queue, mqrq->req, mqrq->bounce_sg);
+ if (mmc_packed_cmd(cmd_type))
+ sg_len = mmc_queue_packed_map_sg(mq, mqrq->packed,
+ mqrq->bounce_sg, cmd_type);
+ else
+ sg_len = blk_rq_map_sg(mq->queue, mqrq->req, mqrq->bounce_sg);
mqrq->bounce_sg_len = sg_len;