linux-kernel - RE: [PATCH] mmc: block: remove non-data R1B ioctl workaround

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Message-ID: <DM6PR04MB6575FEC365167C7347D7FF2FFC119@DM6PR04MB6575.namprd04.prod.outlook.com>
Date:   Sat, 26 Nov 2022 20:18:16 +0000
From:   Avri Altman <Avri.Altman@....com>
To:     Christian Löhle <CLoehle@...erstone.com>,
        "adrian.hunter@...el.com" <adrian.hunter@...el.com>,
        "ulf.hansson@...aro.org" <ulf.hansson@...aro.org>,
        "linux-mmc@...r.kernel.org" <linux-mmc@...r.kernel.org>,
        "linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>
Subject: RE: [PATCH] mmc: block: remove non-data R1B ioctl workaround

> The workaround of pretending R1B non-data transfers are data transfers in
> order for the busy timeout to be respected by the host controller driver is
> removed. It wasn't useful in a long time.
> 
> Initially the workaround ensured that R1B commands did not time out by
> setting the data timeout to be the command timeout in commit
> cb87ea28ed9e ("mmc: core: Add mmc CMD+ACMD passthrough ioctl").
> This was moved inside of an if clause with idata->buf_bytes being set in
> commit 4d6144de8ba2 ("mmc: core: check for zero length ioctl data").
> This patch intends to fix the issuing of R1B data command CMD24.
CMD24 response is R1?

> Its data timeout was being overwritten with 0 because cmd_timeout wasn't
> set at the point the workaround applied, but data_timeout was.
> But since the workaround was now inside of the idata->buf_bytes clause and
> intended to fix R1B non-data transfers that do not have buf_bytes set we can
> also remove the workaround altogether.
I find the above explanation a bit confusing.
Maybe just explain in 1 or 2 sentences why this workaround is no longer needed?

Thanks,
Avri

> 
> Fixes: cb87ea28ed9e ("mmc: core: Add mmc CMD+ACMD passthrough ioctl")
> Signed-off-by: Christian Loehle <cloehle@...erstone.com>
> ---
>  drivers/mmc/core/block.c | 13 -------------
>  1 file changed, 13 deletions(-)
> 
> diff --git a/drivers/mmc/core/block.c b/drivers/mmc/core/block.c index
> db6d8a099910..20da7ed43e6d 100644
> --- a/drivers/mmc/core/block.c
> +++ b/drivers/mmc/core/block.c
> @@ -514,19 +514,6 @@ static int __mmc_blk_ioctl_cmd(struct mmc_card
> *card, struct mmc_blk_data *md,
>                 if (idata->ic.data_timeout_ns)
>                         data.timeout_ns = idata->ic.data_timeout_ns;
> 
> -               if ((cmd.flags & MMC_RSP_R1B) == MMC_RSP_R1B) {
> -                       /*
> -                        * Pretend this is a data transfer and rely on the
> -                        * host driver to compute timeout.  When all host
> -                        * drivers support cmd.cmd_timeout for R1B, this
> -                        * can be changed to:
> -                        *
> -                        *     mrq.data = NULL;
> -                        *     cmd.cmd_timeout = idata->ic.cmd_timeout_ms;
> -                        */
> -                       data.timeout_ns = idata->ic.cmd_timeout_ms * 1000000;
> -               }
> -
>                 mrq.data = &data;
>         }
> 
> --
> 2.37.3
> 
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