linux-kernel - Re: [PATCH v5 04/12] gpio: aggregator: move GPIO forwarder allocation in a dedicated function

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Message-ID: <CAMuHMdVNApWw_z4Gu7wyGx6Zs8ac7dyxZke4OSw1FWseNpfGbQ@mail.gmail.com>
Date: Fri, 9 May 2025 10:05:11 +0200
From: Geert Uytterhoeven <geert@...ux-m68k.org>
To: Thomas Richard <thomas.richard@...tlin.com>
Cc: Linus Walleij <linus.walleij@...aro.org>, 
	Andy Shevchenko <andriy.shevchenko@...ux.intel.com>, Bartosz Golaszewski <brgl@...ev.pl>, 
	Kees Cook <kees@...nel.org>, Andy Shevchenko <andy@...nel.org>, linux-gpio@...r.kernel.org, 
	linux-kernel@...r.kernel.org, thomas.petazzoni@...tlin.com, 
	DanieleCleri@...on.eu, GaryWang@...on.com.tw, linux-hardening@...r.kernel.org
Subject: Re: [PATCH v5 04/12] gpio: aggregator: move GPIO forwarder allocation
 in a dedicated function

Hi Thomas,

On Tue, 6 May 2025 at 17:21, Thomas Richard <thomas.richard@...tlin.com> wrote:
> Move the GPIO forwarder allocation and static initialization in a dedicated
> function.
>
> Reviewed-by: Andy Shevchenko <andriy.shevchenko@...ux.intel.com>
> Signed-off-by: Thomas Richard <thomas.richard@...tlin.com>

Thanks for your patch!

> --- a/drivers/gpio/gpio-aggregator.c
> +++ b/drivers/gpio/gpio-aggregator.c
> @@ -498,6 +498,36 @@ static int gpiochip_fwd_setup_delay_line(struct device *dev, struct gpio_chip *c
>  }
>  #endif /* !CONFIG_OF_GPIO */
>
> +static struct gpiochip_fwd *
> +devm_gpiochip_fwd_alloc(struct device *dev, unsigned int ngpios)
> +{
> +       const char *label = dev_name(dev);
> +       struct gpiochip_fwd *fwd;
> +       struct gpio_chip *chip;
> +
> +       fwd = devm_kzalloc(dev, struct_size(fwd, tmp, fwd_tmp_size(ngpios)), GFP_KERNEL);
> +       if (!fwd)
> +               return ERR_PTR(-ENOMEM);

The caller expects NULL for failures.
So either this return value has to be changed, or the caller needs
to be updated, too.

> +
> +       chip = &fwd->chip;
> +
> +       chip->label = label;

Since you will have to respin this patch anyway, you may want to
drop the label variable, and use dev_name(dev) directly.

> +       chip->parent = dev;
> +       chip->owner = THIS_MODULE;
> +       chip->get_direction = gpio_fwd_get_direction;
> +       chip->direction_input = gpio_fwd_direction_input;
> +       chip->direction_output = gpio_fwd_direction_output;
> +       chip->get = gpio_fwd_get;
> +       chip->get_multiple = gpio_fwd_get_multiple_locked;
> +       chip->set_rv = gpio_fwd_set;
> +       chip->set_multiple_rv = gpio_fwd_set_multiple_locked;
> +       chip->to_irq = gpio_fwd_to_irq;
> +       chip->base = -1;
> +       chip->ngpio = ngpios;
> +
> +       return fwd;
> +}
> +
>  /**
>   * gpiochip_fwd_create() - Create a new GPIO forwarder
>   * @dev: Parent device pointer
> @@ -518,14 +548,12 @@ static struct gpiochip_fwd *gpiochip_fwd_create(struct device *dev,
>                                                 struct gpio_desc *descs[],
>                                                 unsigned long features)
>  {
> -       const char *label = dev_name(dev);
>         struct gpiochip_fwd *fwd;
>         struct gpio_chip *chip;
>         unsigned int i;
>         int error;
>
> -       fwd = devm_kzalloc(dev, struct_size(fwd, tmp, fwd_tmp_size(ngpios)),
> -                          GFP_KERNEL);
> +       fwd = devm_gpiochip_fwd_alloc(dev, ngpios);
>         if (!fwd)
>                 return ERR_PTR(-ENOMEM);
>

Gr{oetje,eeting}s,

                        Geert

-- 
Geert Uytterhoeven -- There's lots of Linux beyond ia32 -- geert@...ux-m68k.org

In personal conversations with technical people, I call myself a hacker. But
when I'm talking to journalists I just say "programmer" or something like that.
                                -- Linus Torvalds