linux-kernel - Re: [PATCH v4 07/13] minmax: Introduce {min,max}

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Date:   Fri, 16 Jun 2023 13:48:44 +0200
From:   Herve Codina <herve.codina@...tlin.com>
To:     David Laight <David.Laight@...LAB.COM>
Cc:     Andy Shevchenko <andy.shevchenko@...il.com>,
        Liam Girdwood <lgirdwood@...il.com>,
        Mark Brown <broonie@...nel.org>,
        "Rob Herring" <robh+dt@...nel.org>,
        Krzysztof Kozlowski <krzysztof.kozlowski+dt@...aro.org>,
        Conor Dooley <conor+dt@...nel.org>,
        Jonathan Cameron <jic23@...nel.org>,
        Lars-Peter Clausen <lars@...afoo.de>,
        Jaroslav Kysela <perex@...ex.cz>,
        Takashi Iwai <tiwai@...e.com>,
        "Kuninori Morimoto" <kuninori.morimoto.gx@...esas.com>,
        "alsa-devel@...a-project.org" <alsa-devel@...a-project.org>,
        "devicetree@...r.kernel.org" <devicetree@...r.kernel.org>,
        "linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>,
        "linux-iio@...r.kernel.org" <linux-iio@...r.kernel.org>,
        Christophe Leroy <christophe.leroy@...roup.eu>,
        Thomas Petazzoni <thomas.petazzoni@...tlin.com>
Subject: Re: [PATCH v4 07/13] minmax: Introduce {min,max}_array()

Hi David,

On Fri, 16 Jun 2023 09:08:22 +0000
David Laight <David.Laight@...LAB.COM> wrote:

...

> 
> Just define two variables typeof(__array[0] + 0) one for an element
> and one for the limit.
> The just test (eg):
> 	if (limit > item) limit = item;
> finally cast the limit back to the original type.
> The promotions of char/short to signed int won't matter.
> There is no need for all the type-checking in min/max.
> 
> Indeed, if min_t(type, a, b) is in anyway sane it should
> expand to:
> 	type _a = a, _b = b;
> 	_a < _b ? _a : _b
> without any of the checks that min() does.

I finally move to use _Generic() in order to "unconstify" and avoid the
integer promotion. With this done, no extra cast is needed and min()/max()
are usable.

The patch is available in the v5 series.
  https://lore.kernel.org/linux-kernel/20230615152631.224529-8-herve.codina@bootlin.com/

Do you think the code present in the v5 series should be changed ?
If so, can you give me your feedback on the v5 series ?

Thanks for your review,
Hervé