RE: [PATCH] mmc: core: Fix error propagation for some ioctl commands

[Avri Altman]

> Userspace has currently has no way of checking the internal R1 response
> error bits for some commands. This is a problem for some commands, like
> RPMB for example. Typically, we may detect that the busy completion
> successfully has ended, while in fact the card did not complete the
> requested operation.
> 
> To fix the problem, let's always poll with CDM13 for these commands and
> during the polling aggregate the R1 response bits. Before completing the
> ioctl request, let's propagate the R1 response bits too.
> 
> Cc: Avri Altman <avri.altman@xxxxxxx>
> Co-developed-by: Christian Loehle <CLoehle@xxxxxxxxxxxxxx>
> Signed-off-by: Christian Loehle <CLoehle@xxxxxxxxxxxxxx>
> Signed-off-by: Ulf Hansson <ulf.hansson@xxxxxxxxxx>
Reviewed-by: Avri Altman <avri.altman@xxxxxxx>

See nit below.
Thanks,
Avri

> ---
> 
> Christian, I took the liberty of re-working your previous patch [1]. But rather
> than keeping your authorship I added you as a co-developer. Please tell me
> if you prefer differently.
> 
> Kind regards
> Uffe
> 
> [1]
> https://lore.kernel.org/all/26d178dcfc2f4b7d9010145d0c051394@hypersto
> ne.com/
> 
> ---
>  drivers/mmc/core/block.c | 31 ++++++++++++++++++++-----------
>  1 file changed, 20 insertions(+), 11 deletions(-)
> 
> diff --git a/drivers/mmc/core/block.c b/drivers/mmc/core/block.c index
> b6f4be25b31b..62a8aacc996c 100644
> --- a/drivers/mmc/core/block.c
> +++ b/drivers/mmc/core/block.c
> @@ -179,6 +179,7 @@ static void mmc_blk_rw_rq_prep(struct
> mmc_queue_req *mqrq,
>                                struct mmc_queue *mq);  static void
> mmc_blk_hsq_req_done(struct mmc_request *mrq);  static int
> mmc_spi_err_check(struct mmc_card *card);
> +static int mmc_blk_busy_cb(void *cb_data, bool *busy);
> 
>  static struct mmc_blk_data *mmc_blk_get(struct gendisk *disk)  { @@ -
> 470,7 +471,7 @@ static int __mmc_blk_ioctl_cmd(struct mmc_card *card,
> struct mmc_blk_data *md,
>         struct mmc_data data = {};
>         struct mmc_request mrq = {};
>         struct scatterlist sg;
> -       bool r1b_resp, use_r1b_resp = false;
> +       bool r1b_resp;
>         unsigned int busy_timeout_ms;
>         int err;
>         unsigned int target_part;
> @@ -551,8 +552,7 @@ static int __mmc_blk_ioctl_cmd(struct mmc_card
> *card, struct mmc_blk_data *md,
>         busy_timeout_ms = idata->ic.cmd_timeout_ms ? :
> MMC_BLK_TIMEOUT_MS;
>         r1b_resp = (cmd.flags & MMC_RSP_R1B) == MMC_RSP_R1B;
>         if (r1b_resp)
> -               use_r1b_resp = mmc_prepare_busy_cmd(card->host, &cmd,
> -                                                   busy_timeout_ms);
> +               mmc_prepare_busy_cmd(card->host, &cmd, busy_timeout_ms);
> 
>         mmc_wait_for_req(card->host, &mrq);
>         memcpy(&idata->ic.response, cmd.resp, sizeof(cmd.resp)); @@ -605,19
> +605,28 @@ static int __mmc_blk_ioctl_cmd(struct mmc_card *card, struct
> mmc_blk_data *md,
>         if (idata->ic.postsleep_min_us)
>                 usleep_range(idata->ic.postsleep_min_us, idata-
> >ic.postsleep_max_us);
> 
> -       /* No need to poll when using HW busy detection. */
> -       if ((card->host->caps & MMC_CAP_WAIT_WHILE_BUSY) &&
> use_r1b_resp)
> -               return 0;
> -
>         if (mmc_host_is_spi(card->host)) {
>                 if (idata->ic.write_flag || r1b_resp || cmd.flags &
> MMC_RSP_SPI_BUSY)
>                         return mmc_spi_err_check(card);
>                 return err;
>         }
> -       /* Ensure RPMB/R1B command has completed by polling with CMD13.
> */
> -       if (idata->rpmb || r1b_resp)
> -               err = mmc_poll_for_busy(card, busy_timeout_ms, false,
> -                                       MMC_BUSY_IO);
> +
> +       /*
> +        * Ensure RPMB, writes and R1B responses are completed by polling
> with
> +        * CMD13. Note that, usually we don't need to poll when using HW busy
> +        * detection, but here it's needed since some commands may indicate
> the
> +        * error through the R1 status bits.
> +        */
> +       if (idata->rpmb || idata->ic.write_flag || r1b_resp) {
> +               struct mmc_blk_busy_data cb_data;
> +
> +               cb_data.card = card;
> +               cb_data.status = 0;
> +               err = __mmc_poll_for_busy(card->host, 0, busy_timeout_ms,
> +                                         &mmc_blk_busy_cb, &cb_data);
Maybe we can pack those 3 lines in an inline handler - they seems to appear a couple of times more.

Thanks,
Avri

> +
> +               idata->ic.response[0] = cb_data.status;
> +       }
> 
>         return err;
>  }
> --
> 2.34.1