[PATCH v6 11/11] mmc: add handling for two parallel block requests in issue_rw_rq

[Kishore Kadiyala]

On Mon, Jun 20, 2011 at 2:47 AM, Per Forlin <per.forlin at linaro.org> wrote:
> Change mmc_blk_issue_rw_rq() to become asynchronous.
> The execution flow looks like this:
> The mmc-queue calls issue_rw_rq(), which sends the request
> to the host and returns back to the mmc-queue. The mmc-queue calls
> issue_rw_rq() again with a new request. This new request is prepared,
> in isuue_rw_rq(), then it waits for the active request to complete before
> pushing it to the host. When to mmc-queue is empty it will call
> isuue_rw_rq() with req=NULL to finish off the active request
> without starting a new request.
>
> Signed-off-by: Per Forlin <per.forlin at linaro.org>
> ---
>  drivers/mmc/card/block.c |  121 +++++++++++++++++++++++++++++++++-------------
>  drivers/mmc/card/queue.c |   17 +++++--
>  drivers/mmc/card/queue.h |    1 +
>  3 files changed, 101 insertions(+), 38 deletions(-)
>
> diff --git a/drivers/mmc/card/block.c b/drivers/mmc/card/block.c
> index 6a84a75..66db77a 100644
> --- a/drivers/mmc/card/block.c
> +++ b/drivers/mmc/card/block.c
> @@ -108,6 +108,7 @@ static DEFINE_MUTEX(open_lock);
>
>  enum mmc_blk_status {
>        MMC_BLK_SUCCESS = 0,
> +       MMC_BLK_PARTIAL,
>        MMC_BLK_RETRY,
>        MMC_BLK_DATA_ERR,
>        MMC_BLK_CMD_ERR,
> @@ -668,14 +669,16 @@ static inline void mmc_apply_rel_rw(struct mmc_blk_request *brq,
>        }
>  }
>
> -static enum mmc_blk_status mmc_blk_err_check(struct mmc_blk_request *brq,
> -                                            struct request *req,
> -                                            struct mmc_card *card,
> -                                            struct mmc_blk_data *md)
> +static int mmc_blk_err_check(struct mmc_card *card,
> +                            struct mmc_async_req *areq)
>  {
>        struct mmc_command cmd;
>        u32 status = 0;
>        enum mmc_blk_status ret = MMC_BLK_SUCCESS;
> +       struct mmc_queue_req *mq_mrq = container_of(areq, struct mmc_queue_req,
> +                                                   mmc_active);
> +       struct mmc_blk_request *brq = &mq_mrq->brq;
> +       struct request *req = mq_mrq->req;
>
>        /*
>         * Check for errors here, but don't jump to cmd_err
> @@ -770,7 +773,11 @@ static enum mmc_blk_status mmc_blk_err_check(struct mmc_blk_request *brq,
>                else
>                        ret = MMC_BLK_DATA_ERR;
>        }
> -out:
> +
> +       if (ret == MMC_BLK_SUCCESS &&
> +           blk_rq_bytes(req) != brq->data.bytes_xfered)
> +               ret = MMC_BLK_PARTIAL;
> + out:
>        return ret;
>  }
>
> @@ -901,27 +908,59 @@ static void mmc_blk_rw_rq_prep(struct mmc_queue_req *mqrq,
>                brq->data.sg_len = i;
>        }
>
> +       mqrq->mmc_active.mrq = &brq->mrq;
> +       mqrq->mmc_active.err_check = mmc_blk_err_check;
> +
>        mmc_queue_bounce_pre(mqrq);
>  }
>
> -static int mmc_blk_issue_rw_rq(struct mmc_queue *mq, struct request *req)
> +static int mmc_blk_issue_rw_rq(struct mmc_queue *mq, struct request *rqc)
>  {
>        struct mmc_blk_data *md = mq->data;
>        struct mmc_card *card = md->queue.card;
> -       struct mmc_blk_request *brq = &mq->mqrq_cur->brq;
> -       int ret = 1, disable_multi = 0;
> +       struct mmc_blk_request *brq;
> +       int ret = 1;
> +       int disable_multi = 0;
>        enum mmc_blk_status status;
> +       struct mmc_queue_req *mq_rq;
> +       struct request *req;
> +       struct mmc_async_req *areq;
> +
> +       if (!rqc && !mq->mqrq_prev->req)
> +               goto out;
>
>        do {
> -               mmc_blk_rw_rq_prep(mq->mqrq_cur, card, disable_multi, mq);
> -               mmc_wait_for_req(card->host, &brq->mrq);
> +               if (rqc) {
> +                       mmc_blk_rw_rq_prep(mq->mqrq_cur, card, 0, mq);
> +                       areq = &mq->mqrq_cur->mmc_active;
> +               } else
> +                       areq = NULL;
> +               areq = mmc_start_req(card->host, areq, (int *) &status);

I think 'status' is used uninitialized.
With this struct mmc_async_req *mmc_start_req in your first patch
if (error)
	*error = err;
return data;
condition which always passes.

You can have
enum mmc_blk_status status = MMC_BLK_SUCCESS;

struct mmc_async_req *mmc_start_req  {
err = host->areq->err_check(host->card, host->areq);
		if (err) {
                             ...
                             ...
                             *error = err;
                }

no need to update * error here in success case
return data
}

Regards,
Kishore