On 14/11/11 13:12, Per Forlin wrote:
> Host is claimed as long as there are requests in the block queue
> and all request are completed successfully. If an error occur release
> the host in case someone else needs to claim it, for instance if the card
> is removed during a transfer.
>
> Signed-off-by: Per Forlin <per.forlin@xxxxxxxxxxxxxx>
> ---
> drivers/mmc/card/block.c | 37 +++++++++++++++++++++++++++++--------
> 1 files changed, 29 insertions(+), 8 deletions(-)
>
> diff --git a/drivers/mmc/card/block.c b/drivers/mmc/card/block.c
> index c80bb6d..c21fd2c 100644
> --- a/drivers/mmc/card/block.c
> +++ b/drivers/mmc/card/block.c
> @@ -1158,6 +1158,28 @@ static int mmc_blk_cmd_err(struct mmc_blk_data *md, struct mmc_card *card,
> return ret;
> }
>
> +/*
> + * This function should be called to resend a request after failure.
> + * Prepares and starts the request.
> + */
> +static inline struct mmc_async_req *mmc_blk_resend(struct mmc_card *card,
> + struct mmc_queue *mq,
> + struct mmc_queue_req *mqrq,
> + int disable_multi,
> + struct mmc_async_req *areq)
> +{
> + /*
> + * Release host after failure in case the host is needed
> + * by someone else. For instance, if the card is removed the
> + * worker thread needs to claim the host in order to do mmc_rescan.
> + */
> + mmc_release_host(card->host);
> + mmc_claim_host(card->host);
Does this work? Won't the current thread win the race
to claim the host again?
> +
> + mmc_blk_rw_rq_prep(mqrq, card, disable_multi, mq);
> + return mmc_start_req(card->host, areq, NULL);
> +}
> +
> static int mmc_blk_issue_rw_rq(struct mmc_queue *mq, struct request *rqc)
> {
> struct mmc_blk_data *md = mq->data;
> @@ -1257,14 +1279,14 @@ static int mmc_blk_issue_rw_rq(struct mmc_queue *mq, struct request *rqc)
> break;
> }
>
> - if (ret) {
> + 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);
> - }
> + mmc_blk_resend(card, mq, mq_rq, disable_multi,
> + &mq_rq->mmc_active);
> +
> } while (ret);
>
> return 1;
> @@ -1276,10 +1298,9 @@ static int mmc_blk_issue_rw_rq(struct mmc_queue *mq, struct request *rqc)
> spin_unlock_irq(&md->lock);
>
> start_new_req:
> - if (rqc) {
> - mmc_blk_rw_rq_prep(mq->mqrq_cur, card, 0, mq);
> - mmc_start_req(card->host, &mq->mqrq_cur->mmc_active, NULL);
> - }
> + if (rqc)
> + mmc_blk_resend(card, mq, mq->mqrq_cur, 0,
> + &mq->mqrq_cur->mmc_active);
>
> return 0;
> }
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