linux-kernel - Re: [PATCH 3/3] Replace for_each_*_bit_from() with for_each_*

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Message-ID: <YM3L1kciMw7zqhUp@smile.fi.intel.com>
Date:   Sat, 19 Jun 2021 13:49:58 +0300
From:   Andy Shevchenko <andriy.shevchenko@...ux.intel.com>
To:     Yury Norov <yury.norov@...il.com>
Cc:     Thomas Gleixner <tglx@...utronix.de>,
        Ingo Molnar <mingo@...hat.com>, Borislav Petkov <bp@...en8.de>,
        "H. Peter Anvin" <hpa@...or.com>,
        Lucas Stach <l.stach@...gutronix.de>,
        Russell King <linux+etnaviv@...linux.org.uk>,
        Christian Gmeiner <christian.gmeiner@...il.com>,
        David Airlie <airlied@...ux.ie>,
        Daniel Vetter <daniel@...ll.ch>,
        Jean Delvare <jdelvare@...e.com>,
        Guenter Roeck <linux@...ck-us.net>,
        Rasmus Villemoes <linux@...musvillemoes.dk>,
        Marc Zyngier <maz@...nel.org>,
        David Woodhouse <dwmw@...zon.co.uk>,
        Andrew Morton <akpm@...ux-foundation.org>,
        Wei Yang <richard.weiyang@...ux.alibaba.com>,
        Geert Uytterhoeven <geert+renesas@...der.be>,
        Alexey Klimov <aklimov@...hat.com>, x86@...nel.org,
        linux-kernel@...r.kernel.org, etnaviv@...ts.freedesktop.org,
        dri-devel@...ts.freedesktop.org, linux-hwmon@...r.kernel.org
Subject: Re: [PATCH 3/3] Replace for_each_*_bit_from() with for_each_*_bit()
 where appropriate

On Fri, Jun 18, 2021 at 12:57:35PM -0700, Yury Norov wrote:
> A couple of kernel functions call for_each_*_bit_from() with start
> bit equal to 0. Replace them with for_each_*_bit().
> 
> No functional changes, but might improve on readability.

...

> --- a/drivers/hwmon/ltc2992.c
> +++ b/drivers/hwmon/ltc2992.c
> @@ -248,8 +248,7 @@ static int ltc2992_gpio_get_multiple(struct gpio_chip *chip, unsigned long *mask
>  
>  	gpio_status = reg;
>  
> -	gpio_nr = 0;
> -	for_each_set_bit_from(gpio_nr, mask, LTC2992_GPIO_NR) {
> +	for_each_set_bit(gpio_nr, mask, LTC2992_GPIO_NR) {
>  		if (test_bit(LTC2992_GPIO_BIT(gpio_nr), &gpio_status))
>  			set_bit(gpio_nr, bits);
>  	}

I would replace the entire loop by bitmap_replace() call.

Something like
	bitmap_replace(bits, bits, &gpio_status, mask, LTC2992_GPIO_NR);

(Good to split sometimes :-)

-- 
With Best Regards,
Andy Shevchenko