Re: [PATCH v7 1/8] bitops: Introduce the for_each_set_clump8 macro

From: Andy Shevchenko
Date: Sat Jan 12 2019 - 03:40:59 EST


On Sat, Jan 12, 2019 at 3:47 AM William Breathitt Gray
<vilhelm.gray@xxxxxxxxx> wrote:
>
> This macro iterates for each 8-bit group of bits (clump) with set bits,
> within a bitmap memory region. For each iteration, "start" is set to the
> bit offset of the found clump, while the respective clump value is
> stored to the location pointed by "clump". Additionally, the
> bitmap_get_value8 and bitmap_set_value8 functions are introduced to
> respectively get and set an 8-bit value in a bitmap memory region.

> +unsigned int bitmap_get_value8(const unsigned long *const bitmap,
> + const unsigned int start);

Hmm... Shouldn't be returned value of type unsigned long for sake of
consistency?

> +/**
> + * bitmap_set_value8 - set an 8-bit value within a memory region
> + * @bitmap: address to the bitmap memory region

> + * @value: the 8-bit value

Put the same warning here as you did in cover letter

> + * @start: bit offset of the 8-bit value
> + */
> +void bitmap_set_value8(unsigned long *const bitmap,
> + const unsigned long value,
> + const unsigned int start)
> +{
> + const size_t index = BIT_WORD(start);
> + const unsigned int offset = start % BITS_PER_LONG;
> + const unsigned long mask = GENMASK(7, offset);
> +
> + bitmap[index] &= ~mask;
> + bitmap[index] |= value << offset;
> +}


--
With Best Regards,
Andy Shevchenko