Sahitya Tummala wrote:
> Hi,
> 
> On 10/27/2011 4:24 PM, Seungwon Jeon wrote:
> >
> > +static int mmc_blk_packed_err_check(struct mmc_card *card,
> > +                        struct mmc_async_req *areq)
> > +{
> > +   struct mmc_queue_req *mq_mrq = container_of(areq, struct mmc_queue_req,
> > +                                               mmc_active);
> > +   int err, check, status;
> > +   u8 ext_csd[512];
> > +
> > +   check = mmc_blk_err_check(card, areq);
> > +
> > +   if (check == MMC_BLK_SUCCESS)
> > +           return check;
> > +
> > +   if (check == MMC_BLK_PARTIAL) {
> > +           err = get_card_status(card,&status, 0);
> > +           if (err)
> > +                   return MMC_BLK_ABORT;
> > +
> > +           if (status&  R1_EXP_EVENT) {
> > +                   err = mmc_send_ext_csd(card, ext_csd);
> > +                   if (err)
> > +                           return MMC_BLK_ABORT;
> > +
> > +                   if ((ext_csd[EXT_CSD_EXP_EVENTS_STATUS + 0]&
> > +                                           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) {
> > +                                   /* Make be 0-based */
> > +                                   mq_mrq->packed_fail_idx =
> > +                                           
> > ext_csd[EXT_CSD_PACKED_FAILURE_INDEX] - 1;
> > +                                   return MMC_BLK_PARTIAL;
> > +                           } else {
> > +                                   return MMC_BLK_RETRY;
> > +                           }
> > +                   }
> > +           } else {
> > +                   return MMC_BLK_RETRY;
> > +           }
> > +   }
> > +
> > +   if (check != MMC_BLK_ABORT)
> > +           return MMC_BLK_RETRY;
> > +   else
> > +           return MMC_BLK_ABORT;
> 
> The current code does not return other errors (MMC_BLK_CMD_ERR,
> MMC_BLK_ECC_ERR and MMC_BLK_DATA_ERR) returned by mmc_blk_err_check().
> Why not return check here?
Currently retry is taken in case of other errors.
But some case needs to be split.
> 
> > +}
> > +
> >   static void mmc_blk_rw_rq_prep(struct mmc_queue_req *mqrq,
> >                            struct mmc_card *card,
> >                            int disable_multi,
> > @@ -1126,6 +1187,207 @@ static void mmc_blk_rw_rq_prep(struct mmc_queue_req 
> > *mqrq,
> >     mmc_queue_bounce_pre(mqrq);
> >   }
> >
> > +static u8 mmc_blk_chk_packable(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;
> > +   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;
> > +   u8 max_packed_rw = 0;
> > +   u8 reqs = 0;
> > +
> > +   if (!(md->flags&  MMC_BLK_CMD23)&&
> > +                   !card->ext_csd.packed_event_en)
> > +           goto no_packed;
> > +
> > +   if (rq_data_dir(cur) == READ)
> > +           max_packed_rw = card->ext_csd.max_packed_reads;
> > +   else
> > +           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;
> > +   }
> > +
> > +   max_blk_count = min(card->host->max_blk_count,
> > +                   card->host->max_req_size>>  9);
> > +   max_phys_segs = queue_max_segments(q);
> > +   req_sectors += blk_rq_sectors(cur);
> > +   phys_segments += req->nr_phys_segments;
> > +
> > +   if (rq_data_dir(cur) == WRITE) {
> > +           req_sectors++;
> > +           phys_segments++;
> > +   }
> > +
> > +   while (reqs<  max_packed_rw - 1) {
> 
> What if the number of requests exceeds the packed header size defined?
Currently not considered.
That case is maximum r/w depth from eMMC device is wrong, right?
It may not happen in practice. But the limit may need to restricted.
> 
> > +           next = blk_fetch_request(q);
> > +           if (!next)
> > +                   break;
> > +
> > +           if (rq_data_dir(cur) != rq_data_dir(next)) {
> > +                   blk_requeue_request(q, next);
> > +                   break;
> > +           }
> > +
> > +           if (mmc_req_rel_wr(next)&&
> > +                           (md->flags&  MMC_BLK_REL_WR)&&
> > +                           !en_rel_wr) {
> > +                   blk_requeue_request(q, next);
> > +                   break;
> > +           }
> > +
> > +           req_sectors += blk_rq_sectors(next);
> > +           if (req_sectors>  max_blk_count) {
> > +                   blk_requeue_request(q, next);
> > +                   break;
> > +           }
> > +
> > +           phys_segments +=  next->nr_phys_segments;
> > +           if (phys_segments>  max_phys_segs) {
> > +                   blk_requeue_request(q, next);
> > +                   break;
> > +           }
> > +
> > +           list_add_tail(&next->queuelist,&mq->mqrq_cur->packed_list);
> > +           cur = next;
> > +           reqs++;
> > +   }
> > +
> > +   if (reqs>  0) {
> > +           list_add(&req->queuelist,&mq->mqrq_cur->packed_list);
> > +           return (reqs + 1);
> > +   }
> > +
> > +no_packed:
> > +   mq->mqrq_cur->packed_cmd = MMC_PACKED_NONE;
> > +   return reqs;
> > +}
> > +
> >
> >   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)
> > @@ -1163,15 +1425,33 @@ static int mmc_blk_issue_rw_rq(struct mmc_queue 
> > *mq, struct request *rqc)
> >     int ret = 1, disable_multi = 0, retry = 0, type;
> >     enum mmc_blk_status status;
> >     struct mmc_queue_req *mq_rq;
> > -   struct request *req;
> > +   struct request *req, *prq;
> >     struct mmc_async_req *areq;
> > +   u8 reqs = 0;
> >
> >     if (!rqc&&  !mq->mqrq_prev->req)
> >             return 0;
> >
> > +   if (rqc)
> > +           reqs = mmc_blk_chk_packable(mq, rqc);
> > +
> >     do {
> >             if (rqc) {
> > -                   mmc_blk_rw_rq_prep(mq->mqrq_cur, card, 0, mq);
> > +                   if (reqs>= 2) {
> > +                           mmc_blk_packed_hdr_wrq_prep(mq->mqrq_cur, card, 
> > mq, reqs);
> > +                           if (rq_data_dir(rqc) == READ) {
> > +                                   areq =&mq->mqrq_cur->mmc_active;
> > +                                   mmc_wait_for_req(card->host, areq->mrq);
> > +                                   status = mmc_blk_packed_err_check(card, 
> > areq);
> > +                                   if (status == MMC_BLK_SUCCESS) {
> > +                                           
> > mmc_blk_packed_rrq_prep(mq->mqrq_cur, card, mq);
> > +                                   } else {
> > +                                           goto check_status;
> > +                                   }
> > +                           }
> > +                   } else {
> > +                           mmc_blk_rw_rq_prep(mq->mqrq_cur, card, 0, mq);
> 
> We must use disable_multi variable instead of directly calling this
> function with 0 value because there are some cases where disable_multi
> is set to 1 (for example, it is set for error case MMC_BLK_ECC_ERR).
This part is origin code for non-packed case. 
It just is moved to else statement.
if (rqc) {
-       mmc_blk_rw_rq_prep(mq->mqrq_cur, card, 0, mq);

> 
> > +                   }
> >                     areq =&mq->mqrq_cur->mmc_active;
> >             } else
> >                     areq = NULL;
> > @@ -1179,6 +1459,7 @@ static int mmc_blk_issue_rw_rq(struct mmc_queue *mq, 
> > struct request *rqc)
> >             if (!areq)
> >                     return 0;
> >
> > +check_status:
> >             mq_rq = container_of(areq, struct mmc_queue_req, mmc_active);
> >             brq =&mq_rq->brq;
> >             req = mq_rq->req;
> > @@ -1192,10 +1473,32 @@ static int mmc_blk_issue_rw_rq(struct mmc_queue 
> > *mq, struct request *rqc)
> >                      * A block was successfully transferred.
> >                      */
> >                     mmc_blk_reset_success(md, type);
> > -                   spin_lock_irq(&md->lock);
> > -                   ret = __blk_end_request(req, 0,
> > +
> > +                   if (mq_rq->packed_cmd != MMC_PACKED_NONE) {
> > +                           int idx = mq_rq->packed_fail_idx, i = 0;
> > +                           while (!list_empty(&mq_rq->packed_list)) {
> > +                                   prq = 
> > list_entry_rq(mq_rq->packed_list.next);
> > +                                   if (idx == i) {
> > +                                           /* retry from error index */
> > +                                           reqs -= idx;
> > +                                           mq_rq->req = prq;
> > +                                           ret = 1;
> > +                                           break;
> > +                                   }
> > +                                   list_del_init(&prq->queuelist);
> > +                                   spin_lock_irq(&md->lock);
> > +                                   ret = __blk_end_request(prq, 0, 
> > blk_rq_bytes(prq));
> > +                                   spin_unlock_irq(&md->lock);
> > +                                   i++;
> > +                           }
> > +                           break;
> > +                   } else {
> > +                           spin_lock_irq(&md->lock);
> > +                           ret = __blk_end_request(req, 0,
> >                                             brq->data.bytes_xfered);
> > -                   spin_unlock_irq(&md->lock);
> > +                           spin_unlock_irq(&md->lock);
> > +                   }
> > +
> >                     /*
> >                      * If the blk_end_request function returns non-zero even
> >                      * though all data has been transferred and no errors
> > @@ -1254,7 +1557,7 @@ static int mmc_blk_issue_rw_rq(struct mmc_queue *mq, 
> > struct request *rqc)
> >                     break;
> >             }
> >
> > -           if (ret) {
> > +           if (ret&&  (mq_rq->packed_cmd == MMC_PACKED_NONE)) {
> >                     /*
> >                      * In case of a incomplete request
> >                      * prepare it again and resend.
> > @@ -1267,13 +1570,37 @@ static int mmc_blk_issue_rw_rq(struct mmc_queue 
> > *mq, struct request *rqc)
> >     return 1;
> >
> >    cmd_abort:
> > -   spin_lock_irq(&md->lock);
> > -   while (ret)
> > -           ret = __blk_end_request(req, -EIO, blk_rq_cur_bytes(req));
> > -   spin_unlock_irq(&md->lock);
> > +   if (mq_rq->packed_cmd != MMC_PACKED_NONE) {
> > +           spin_lock_irq(&md->lock);
> > +           while (ret)
> > +                   ret = __blk_end_request(req, -EIO, 
> > blk_rq_cur_bytes(req));
> > +           spin_unlock_irq(&md->lock);
> > +   } else {
> > +           while (!list_empty(&mq_rq->packed_list)) {
> > +                   prq = list_entry_rq(mq_rq->packed_list.next);
> > +                   list_del_init(&prq->queuelist);
> > +                   spin_lock_irq(&md->lock);
> > +                   __blk_end_request(prq, -EIO, blk_rq_bytes(prq));
> > +                   spin_unlock_irq(&md->lock);
> > +           }
> > +   }
> >
> >    start_new_req:
> >     if (rqc) {
> > +           /*
> > +            * If current request is packed, it need to put back.
> > +            */
> > +           if (mq->mqrq_cur->packed_cmd != MMC_PACKED_NONE) {
> > +                   while (!list_empty(&mq->mqrq_cur->packed_list)) {
> > +                           prq = 
> > list_entry_rq(mq->mqrq_cur->packed_list.prev);
> > +                           if (prq->queuelist.prev 
> > !=&mq->mqrq_cur->packed_list) {
> > +                                   list_del_init(&prq->queuelist);
> > +                                   blk_requeue_request(mq->queue, prq);
> > +                           } else {
> > +                                   list_del_init(&prq->queuelist);
> > +                           }
> > +                   }
> > +           }
> >             mmc_blk_rw_rq_prep(mq->mqrq_cur, card, 0, mq);
> 
> We must use disable_multi variable instead of directly calling this
> function with 0 value because there are some cases where disable_multi
> is set to 1.
This part is also origin code for non-packed case.
> 
> >             mmc_start_req(card->host,&mq->mqrq_cur->mmc_active, NULL);
> 
> I think these two statements must come under else part of above if
> condition. Please check.
This two statements are applicable regardless of packed command.

Best regards,
Seungwon Jeon.
> 
> Thanks,
> Sahitya.
> --
> Sent by a consultant of the Qualcomm Innovation Center, Inc.
> The Qualcomm Innovation Center, Inc. is a member of the Code Aurora
> Forum.


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