Re: [PATCH] mmc: core: sd: Remove unused buffer allocation in sd_enable_cache()

[Ulf Hansson]

On Tue, Jun 2, 2026 at 11:41 AM Chanwoo Lee <cw9316.lee@xxxxxxxxxxx> wrote:
>
> sd_enable_cache() allocates a 512-byte buffer that is never used.
> sd_write_ext_reg() allocates its own internal buffer, and no read-back
> verification is done in this function. Remove the unnecessary allocation.
>
> Fixes: 130206a615a9 ("mmc: core: Add support for cache ctrl for SD cards")
> Signed-off-by: Chanwoo Lee <cw9316.lee@xxxxxxxxxxx>

Applied for next, thanks!

Kind regards
Uffe


> ---
>  drivers/mmc/core/sd.c | 9 +--------
>  1 file changed, 1 insertion(+), 8 deletions(-)
>
> diff --git a/drivers/mmc/core/sd.c b/drivers/mmc/core/sd.c
> index 948948ca9b4a..c763efb10f64 100644
> --- a/drivers/mmc/core/sd.c
> +++ b/drivers/mmc/core/sd.c
> @@ -1379,15 +1379,10 @@ static int sd_flush_cache(struct mmc_host *host)
>
>  static int sd_enable_cache(struct mmc_card *card)
>  {
> -       u8 *reg_buf;
>         int err;
>
>         card->ext_perf.feature_enabled &= ~SD_EXT_PERF_CACHE;
>
> -       reg_buf = kzalloc(512, GFP_KERNEL);
> -       if (!reg_buf)
> -               return -ENOMEM;
> -
>         /*
>          * Set Cache Enable at bit 0 in the performance enhancement register at
>          * 260 bytes offset.
> @@ -1397,7 +1392,7 @@ static int sd_enable_cache(struct mmc_card *card)
>         if (err) {
>                 pr_warn("%s: error %d writing Cache Enable bit\n",
>                         mmc_hostname(card->host), err);
> -               goto out;
> +               return err;
>         }
>
>         err = mmc_poll_for_busy(card, SD_WRITE_EXTR_SINGLE_TIMEOUT_MS, false,
> @@ -1405,8 +1400,6 @@ static int sd_enable_cache(struct mmc_card *card)
>         if (!err)
>                 card->ext_perf.feature_enabled |= SD_EXT_PERF_CACHE;
>
> -out:
> -       kfree(reg_buf);
>         return err;
>  }
>
> --
> 2.43.0
>