linux-kernel - Re: [PATCH v7 01/16] pinctrl: check the return value of pinmux_ops::get_function

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Message-ID: <aLbrz5DYS5Yxx_UE@smile.fi.intel.com>
Date: Tue, 2 Sep 2025 16:06:23 +0300
From: Andy Shevchenko <andriy.shevchenko@...el.com>
To: Bartosz Golaszewski <brgl@...ev.pl>
Cc: Linus Walleij <linus.walleij@...aro.org>,
	Bjorn Andersson <andersson@...nel.org>,
	Konrad Dybcio <konradybcio@...nel.org>,
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	Andy Shevchenko <andy@...nel.org>,
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	Mark Brown <broonie@...nel.org>, linux-gpio@...r.kernel.org,
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	Bartosz Golaszewski <bartosz.golaszewski@...aro.org>,
	stable@...r.kernel.org
Subject: Re: [PATCH v7 01/16] pinctrl: check the return value of
 pinmux_ops::get_function_name()

On Tue, Sep 02, 2025 at 01:59:10PM +0200, Bartosz Golaszewski wrote:
> From: Bartosz Golaszewski <bartosz.golaszewski@...aro.org>
> 
> While the API contract in docs doesn't specify it explicitly,

So, why not to amend the doc at the same time?

> the generic implementation of the get_function_name() callback from struct
> pinmux_ops - pinmux_generic_get_function_name() - can fail and return
> NULL. This is already checked in pinmux_check_ops() so add a similar
> check in pinmux_func_name_to_selector() instead of passing the returned
> pointer right down to strcmp() where the NULL can get dereferenced. This
> is normal operation when adding new pinfunctions.

Fixes?
Reported?
Closes?

...

>  	while (selector < nfuncs) {
>  		const char *fname = ops->get_function_name(pctldev, selector);
>  
> -		if (!strcmp(function, fname))
> +		if (fname && !strcmp(function, fname))
>  			return selector;

I would slightly refactor this:

		const char *fname;

		fname = ops->get_function_name(pctldev, selector);
		if (fname && !strcmp(function, fname))
			return selector;

>  		selector++;

-- 
With Best Regards,
Andy Shevchenko