Re: [PATCH v7 1/5] lib/bitmap: add bitmap_{read,write}()

On Wed, Oct 11, 2023 at 07:28:31PM +0200, Alexander Potapenko wrote:

From: Syed Nayyar Waris <redacted>

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



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