[Linux-stm32] [PATCH 01/13] mmc: mmci: Only call busy_complete if callback defined

[Ulf Hansson]

On Wed, 5 Apr 2023 at 08:50, Linus Walleij <linus.walleij at linaro.org> wrote:
>
> The code unconditionally calls host->ops->busy_complete()
> if we get a busy response and the variant supports busy
> detection (variant->busy_detect = true).
>
> However there are several STM32 variants that define
> variant->busy_detect to true but do not define any
> busy_complete() callback. This looks like a recepie for
> a NULL pointer exception.

This isn't correct, as things would have exploded by now. :-)

>
> Check that the callback is valid before calling it.
>
> Signed-off-by: Linus Walleij <linus.walleij at linaro.org>
> ---
>  drivers/mmc/host/mmci.c | 2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)
>
> diff --git a/drivers/mmc/host/mmci.c b/drivers/mmc/host/mmci.c
> index b9e5dfe74e5c..bc150c0d5eed 100644
> --- a/drivers/mmc/host/mmci.c
> +++ b/drivers/mmc/host/mmci.c
> @@ -1381,7 +1381,7 @@ mmci_cmd_irq(struct mmci_host *host, struct mmc_command *cmd,
>                 return;
>
>         /* Handle busy detection on DAT0 if the variant supports it. */
> -       if (busy_resp && host->variant->busy_detect)
> +       if (busy_resp && host->variant->busy_detect && host->ops->busy_complete)
>                 if (!host->ops->busy_complete(host, status, err_msk))
>                         return;

All variants that have the .busy_detect flags set, need to assign the
->busy_complete() callback too.

To me it seems a bit silly, to check for a mandatory callback,
although if you prefer it, then I suggest we do it during ->probe()
instead.

Kind regards
Uffe