Re: [PATCH V2] mmc: core: Detect card removal on I/O error

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2012/2/1 Ulf Hansson <ulf.hansson@xxxxxxxxxxxxxx>:
> To prevent I/O as soon as possible at card removal, a new
> detect work is re-scheduled without a delay to let a rescan
> remove the card device as soon a possible.
>
> Additionally, MMC_CAP2_DETECT_ON_ERR can now be used to handle
> "slowly" removed cards that a scheduled detect work did not
> detect as removed. To prevent further I/O requests for these
> lingering removed cards, check if card has been removed and then
> schedule a detect work to properly remove it.
>
> Signed-off-by: Ulf Hansson <ulf.hansson@xxxxxxxxxxxxxx>
> ---
>
> Changes in v2:
>        - Updated according to review comments.
>        - Merging two patches for this feature into one.
>
> ---
>  drivers/mmc/core/core.c  |   19 +++++++++++++++++--
>  include/linux/mmc/host.h |    1 +
>  2 files changed, 18 insertions(+), 2 deletions(-)
>
> diff --git a/drivers/mmc/core/core.c b/drivers/mmc/core/core.c
> index bec0bf2..26d3a66 100644
> --- a/drivers/mmc/core/core.c
> +++ b/drivers/mmc/core/core.c
> @@ -2077,18 +2077,33 @@ int _mmc_detect_card_removed(struct mmc_host *host)
>  int mmc_detect_card_removed(struct mmc_host *host)
>  {
>        struct mmc_card *card = host->card;
> +       int ret;
>
>        WARN_ON(!host->claimed);
>        /*
>         * The card will be considered unchanged unless we have been asked to
>         * detect a change or host requires polling to provide card detection.
>         */
> -       if (card && !host->detect_change && !(host->caps & MMC_CAP_NEEDS_POLL))
> +       if (card && !host->detect_change && !(host->caps & MMC_CAP_NEEDS_POLL)
> +           && !(host->caps2 & MMC_CAP2_DETECT_ON_ERR))
>                return mmc_card_removed(card);
>
>        host->detect_change = 0;
>
> -       return _mmc_detect_card_removed(host);
> +       ret = mmc_card_removed(card);
Hi. Ulf.
1. Is there no case that card is null ?
2. and Eventually mmc_card_removed is once called in any case. can we
change it like this ?

if (card)
   ret = mmc_card_removed(card);

   if(!host->detect_change && !(host->caps & MMC_CAP_NEEDS_POLL)
           && !(host->caps2 & MMC_CAP2_DETECT_ON_ERR))
                  return ret;

> +       if (!ret) {
> +               ret = _mmc_detect_card_removed(host);
> +               if (ret) {
> +                       /*
> +                        * Schedule a detect work as soon as possible to let a
> +                        * rescan handle the card removal.
> +                        */
> +                       cancel_delayed_work(&host->detect);
> +                       mmc_detect_change(host, 0);
> +               }
> +       }
> +
> +       return ret;
>  }
>  EXPORT_SYMBOL(mmc_detect_card_removed);
>
> diff --git a/include/linux/mmc/host.h b/include/linux/mmc/host.h
> index dd13e05..368a2b9 100644
> --- a/include/linux/mmc/host.h
> +++ b/include/linux/mmc/host.h
> @@ -257,6 +257,7 @@ struct mmc_host {
>  #define MMC_CAP2_HS200_1_2V_SDR        (1 << 6)        /* can support */
>  #define MMC_CAP2_HS200         (MMC_CAP2_HS200_1_8V_SDR | \
>                                 MMC_CAP2_HS200_1_2V_SDR)
> +#define MMC_CAP2_DETECT_ON_ERR (1 << 7)        /* On I/O err check card removal */
>
>        mmc_pm_flag_t           pm_caps;        /* supported pm features */
>        unsigned int        power_notify_type;
> --
> 1.7.5.4
>
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