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From:   Andy Shevchenko <andy.shevchenko@gmail.com>
Date:   Mon, 29 Mar 2021 14:56:22 +0300
Message-ID: <CAHp75VeaEGbnyro2UUCddNxZaKHSWyfyDmExV6s7a0TJKGnkNA@mail.gmail.com>
Subject: Re: [PATCH 1/2] gpio: sysfs: Obey valid_mask
To:     Matti Vaittinen <matti.vaittinen@fi.rohmeurope.com>
Cc:     Matti Vaittinen <mazziesaccount@gmail.com>,
        Linus Walleij <linus.walleij@linaro.org>,
        Bartosz Golaszewski <bgolaszewski@baylibre.com>,
        Stephen Boyd <sboyd@codeaurora.org>,
        Andy Shevchenko <andriy.shevchenko@linux.intel.com>,
        "open list:GPIO SUBSYSTEM" <linux-gpio@vger.kernel.org>,
        Linux Kernel Mailing List <linux-kernel@vger.kernel.org>
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Precedence: bulk

On Mon, Mar 29, 2021 at 2:42 PM Matti Vaittinen
<matti.vaittinen@fi.rohmeurope.com> wrote:
>
> Do not allow exporting GPIOs which are set invalid
> by the driver's valid mask.

> Fixes: 726cb3ba49692bdae6caff457755e7cdb432efa4
>
> Signed-off-by: Matti Vaittinen <matti.vaittinen@fi.rohmeurope.com>

Should not be blank lines in the tag block.

Dunno if you can convert those pr_*() to dev_*(), but it's definitely
out of the scope here.

I like the idea, FWIW,
Reviewed-by: Andy Shevchenko <andy.shevchenko@gmail.com>

> ---
>  drivers/gpio/gpiolib-sysfs.c | 8 ++++++++
>  1 file changed, 8 insertions(+)
>
> diff --git a/drivers/gpio/gpiolib-sysfs.c b/drivers/gpio/gpiolib-sysfs.c
> index 26c5466b8179..ae49bb23c6ed 100644
> --- a/drivers/gpio/gpiolib-sysfs.c
> +++ b/drivers/gpio/gpiolib-sysfs.c
> @@ -458,6 +458,8 @@ static ssize_t export_store(struct class *class,
>         long                    gpio;
>         struct gpio_desc        *desc;
>         int                     status;
> +       struct gpio_chip        *gc;
> +       int                     offset;
>
>         status = kstrtol(buf, 0, &gpio);
>         if (status < 0)
> @@ -469,6 +471,12 @@ static ssize_t export_store(struct class *class,
>                 pr_warn("%s: invalid GPIO %ld\n", __func__, gpio);
>                 return -EINVAL;
>         }
> +       gc = desc->gdev->chip;
> +       offset = gpio_chip_hwgpio(desc);
> +       if (!gpiochip_line_is_valid(gc, offset)) {
> +               pr_warn("%s: GPIO %ld masked\n", __func__, gpio);
> +               return -EINVAL;
> +       }
>
>         /* No extra locking here; FLAG_SYSFS just signifies that the
>          * request and export were done by on behalf of userspace, so
> --
> 2.25.4
>
>
> --
> Matti Vaittinen, Linux device drivers
> ROHM Semiconductors, Finland SWDC
> Kiviharjunlenkki 1E
> 90220 OULU
> FINLAND
>
> ~~~ "I don't think so," said Rene Descartes. Just then he vanished ~~~
> Simon says - in Latin please.
> ~~~ "non cogito me" dixit Rene Descarte, deinde evanescavit ~~~
> Thanks to Simon Glass for the translation =]


-- 
With Best Regards,
Andy Shevchenko