linux-kernel - Re: [PATCHv5 1/2] mmc: block: Remove error check of hw

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Date:   Thu, 13 Oct 2022 16:20:40 +0200
From:   Ulf Hansson <ulf.hansson@...aro.org>
To:     Christian Löhle <CLoehle@...erstone.com>
Cc:     Linux MMC List <linux-mmc@...r.kernel.org>,
        "linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>,
        Adrian Hunter <adrian.hunter@...el.com>
Subject: Re: [PATCHv5 1/2] mmc: block: Remove error check of hw_reset on reset

On Thu, 13 Oct 2022 at 13:16, Christian Löhle <CLoehle@...erstone.com> wrote:
>
> Before switching back to the right partition in mmc_blk_reset there used
> to be a check if hw_reset was even supported. This return value
> was removed, so there is no reason to check. Furthermore ensure
> part_curr is not falsely set to a valid value on reset or
> partition switch error.
>
> As part of this change the code paths of mmc_blk_reset calls were checked
> to ensure no commands are issued after a failed mmc_blk_reset directly
> without going through the block layer.
>
> Fixes: fefdd3c91e0a ("mmc: core: Drop superfluous validations in mmc_hw|sw_reset()")
> Cc: stable@...r.kernel.org
>
> Signed-off-by: Christian Loehle <cloehle@...erstone.com>
> Reviewed-by: Adrian Hunter <adrian.hunter@...el.com>

Applied for fixes, thanks!

Kind regards
Uffe


> ---
> -v5: Remove nested if
> -v4: Only partition switch if necessary and fix one mmc_blk_reset call
> -v3: Ensure invalid part_curr on error
> -v2: Do not attempt to switch partitions if reset failed
>
>  drivers/mmc/core/block.c | 44 ++++++++++++++++++++++++----------------
>  1 file changed, 26 insertions(+), 18 deletions(-)
>
> diff --git a/drivers/mmc/core/block.c b/drivers/mmc/core/block.c
> index ce89611a136e..0be7ab6ce1c8 100644
> --- a/drivers/mmc/core/block.c
> +++ b/drivers/mmc/core/block.c
> @@ -134,6 +134,7 @@ struct mmc_blk_data {
>          * track of the current selected device partition.
>          */
>         unsigned int    part_curr;
> +#define MMC_BLK_PART_INVALID   UINT_MAX        /* Unknown partition active */
>         int     area_type;
>
>         /* debugfs files (only in main mmc_blk_data) */
> @@ -987,33 +988,39 @@ static unsigned int mmc_blk_data_timeout_ms(struct mmc_host *host,
>         return ms;
>  }
>
> +/*
> + * Attempts to reset the card and get back to the requested partition.
> + * Therefore any error here must result in cancelling the block layer
> + * request, it must not be reattempted without going through the mmc_blk
> + * partition sanity checks.
> + */
>  static int mmc_blk_reset(struct mmc_blk_data *md, struct mmc_host *host,
>                          int type)
>  {
>         int err;
> +       struct mmc_blk_data *main_md = dev_get_drvdata(&host->card->dev);
>
>         if (md->reset_done & type)
>                 return -EEXIST;
>
>         md->reset_done |= type;
>         err = mmc_hw_reset(host->card);
> +       /*
> +        * A successful reset will leave the card in the main partition, but
> +        * upon failure it might not be, so set it to MMC_BLK_PART_INVALID
> +        * in that case.
> +        */
> +       main_md->part_curr = err ? MMC_BLK_PART_INVALID : main_md->part_type;
> +       if (err)
> +               return err;
>         /* Ensure we switch back to the correct partition */
> -       if (err) {
> -               struct mmc_blk_data *main_md =
> -                       dev_get_drvdata(&host->card->dev);
> -               int part_err;
> -
> -               main_md->part_curr = main_md->part_type;
> -               part_err = mmc_blk_part_switch(host->card, md->part_type);
> -               if (part_err) {
> -                       /*
> -                        * We have failed to get back into the correct
> -                        * partition, so we need to abort the whole request.
> -                        */
> -                       return -ENODEV;
> -               }
> -       }
> -       return err;
> +       if (mmc_blk_part_switch(host->card, md->part_type))
> +               /*
> +                * We have failed to get back into the correct
> +                * partition, so we need to abort the whole request.
> +                */
> +               return -ENODEV;
> +       return 0;
>  }
>
>  static inline void mmc_blk_reset_success(struct mmc_blk_data *md, int type)
> @@ -1867,8 +1874,9 @@ static void mmc_blk_mq_rw_recovery(struct mmc_queue *mq, struct request *req)
>                 return;
>
>         /* Reset before last retry */
> -       if (mqrq->retries + 1 == MMC_MAX_RETRIES)
> -               mmc_blk_reset(md, card->host, type);
> +       if (mqrq->retries + 1 == MMC_MAX_RETRIES &&
> +           mmc_blk_reset(md, card->host, type))
> +               return;
>
>         /* Command errors fail fast, so use all MMC_MAX_RETRIES */
>         if (brq->sbc.error || brq->cmd.error)
> --
> 2.37.3
>
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