linux-kernel - Re: [PATCH v1] gpio: mmio: restroe get multiple gpio mask

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Date:   Mon, 24 Apr 2023 16:31:39 +0300
From:   Andy Shevchenko <andriy.shevchenko@...ux.intel.com>
To:     Yan Wang <rk.code@...look.com>
Cc:     linus.walleij@...aro.org, brgl@...ev.pl,
        "open list:GPIO SUBSYSTEM" <linux-gpio@...r.kernel.org>,
        open list <linux-kernel@...r.kernel.org>
Subject: Re: [PATCH v1] gpio: mmio: restroe get multiple gpio mask

On Sun, Apr 23, 2023 at 05:06:48PM +0800, Yan Wang wrote:
> Simplify the code,should not modify its logic.

> Fixes: 761b5c30c206 ("gpio: mmio: replace open-coded for_each_set_bit()")

What does it fix?

...

>  	for_each_set_bit(i, mask, gc->bgpio_bits) {
> -		if (test_bit(i, bits))
> -			*set_mask |= bgpio_line2mask(gc, i);
> -		else
> -			*clear_mask |= bgpio_line2mask(gc, i);
> +		if (*mask == 0)
> +			break;

Huh?!

We never enter here if mask is 0. So, do not add a dead code, please.

Moreover, in principle mask can be longer than 1 long, this code simply wrong.

NAK

> +		if (__test_and_clear_bit(i, mask)) {
> +			if (test_bit(i, bits))
> +				*set_mask |= bgpio_line2mask(gc, i);
> +			else
> +				*clear_mask |= bgpio_line2mask(gc, i);
> +		}
>  	}

-- 
With Best Regards,
Andy Shevchenko