Linux GPIO subsystem development
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From: "Uwe Kleine-König" <u.kleine-koenig@baylibre.com>
To: Ruoyu Wang <ruoyuw560@gmail.com>
Cc: Linus Walleij <linusw@kernel.org>,
	 Bartosz Golaszewski <brgl@kernel.org>,
	linux-gpio@vger.kernel.org, linux-kernel@vger.kernel.org
Subject: Re: [PATCH] gpiolib: initialize return value in gpiochip_set_multiple()
Date: Sat, 20 Jun 2026 18:45:03 +0200	[thread overview]
Message-ID: <ajbCt5hAiqanKZ2f@monoceros> (raw)
In-Reply-To: <20260620155319.79994-1-ruoyuw560@gmail.com>

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On Sat, Jun 20, 2026 at 11:53:19PM +0800, Ruoyu Wang wrote:
> gpiochip_set_multiple() falls back to setting lines one by one when the
> chip does not provide set_multiple(). If the fallback path receives an
> empty mask, the loop is skipped and ret is returned without being
> initialized.
> 
> Initialize ret to 0 so an empty mask is treated as a successful no-op.
> 
> Fixes: 9b407312755f ("gpiolib: rework the wrapper around gpio_chip::set_multiple()")
> Signed-off-by: Ruoyu Wang <ruoyuw560@gmail.com>
> ---
>  drivers/gpio/gpiolib.c | 2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)
> 
> diff --git a/drivers/gpio/gpiolib.c b/drivers/gpio/gpiolib.c
> index 1e6dce430dca..cd2a619da456 100644
> --- a/drivers/gpio/gpiolib.c
> +++ b/drivers/gpio/gpiolib.c
> @@ -3778,7 +3778,7 @@ static int gpiochip_set_multiple(struct gpio_chip *gc,
>  				 unsigned long *mask, unsigned long *bits)
>  {
>  	unsigned int i;
> -	int ret;
> +	int ret = 0;
>  
>  	lockdep_assert_held(&gc->gpiodev->srcu);

While I think it's questionable to call gpiochip_set_multiple with an
empty mask, returning a random value isn't the right reaction.

Acked-by: Uwe Kleine-König <u.kleine-koenig@baylibre.com>

Did you find that by manual code inspection, or using a tool?

Best regards
Uwe
>  

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      reply	other threads:[~2026-06-20 16:45 UTC|newest]

Thread overview: 2+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2026-06-20 15:53 [PATCH] gpiolib: initialize return value in gpiochip_set_multiple() Ruoyu Wang
2026-06-20 16:45 ` Uwe Kleine-König [this message]

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