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Date:   Wed, 11 Oct 2023 20:59:59 +0300
From:   Andy Shevchenko <andriy.shevchenko@linux.intel.com>
To:     Alexander Potapenko <glider@google.com>
Cc:     catalin.marinas@arm.com, will@kernel.org, pcc@google.com,
        andreyknvl@gmail.com, aleksander.lobakin@intel.com,
        linux@rasmusvillemoes.dk, yury.norov@gmail.com,
        alexandru.elisei@arm.com, linux-kernel@vger.kernel.org,
        linux-arm-kernel@lists.infradead.org, eugenis@google.com,
        syednwaris@gmail.com, william.gray@linaro.org,
        Arnd Bergmann <arnd@arndb.de>
Subject: Re: [PATCH v7 1/5] lib/bitmap: add bitmap_{read,write}()
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On Wed, Oct 11, 2023 at 07:28:31PM +0200, Alexander Potapenko wrote:
> From: Syed Nayyar Waris <syednwaris@gmail.com>
> 
> The two new functions allow reading/writing values of length up to
> BITS_PER_LONG bits at arbitrary position in the bitmap.
> 
> The code was taken from "bitops: Introduce the for_each_set_clump macro"
> by Syed Nayyar Waris with a number of changes and simplifications:
>  - instead of using roundup(), which adds an unnecessary dependency
>    on <linux/math.h>, we calculate space as BITS_PER_LONG-offset;
>  - indentation is reduced by not using else-clauses (suggested by
>    checkpatch for bitmap_get_value());
>  - bitmap_get_value()/bitmap_set_value() are renamed to bitmap_read()
>    and bitmap_write();
>  - some redundant computations are omitted.

I realized that the corner case with these functions is when agnostic user
wants to read / write > 32 bits at a time without ifdeffery applied.

At bare minimum this has to be documented explicitly, that callers
may have an issue of the above calls on 32-bit platforms.

-- 
With Best Regards,
Andy Shevchenko