On Sun, Oct 06, 2019 at 11:10:58AM -0400, William Breathitt Gray 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.
Very much thank you for an update!
I have comments below.
> +/**
> + * bitmap_get_value8 - get an 8-bit value within a memory region
Since it's in find.h I would not collide with bitmap namespace.
How about
find_and_get_value8()
> + * @addr: address to the bitmap memory region
> + * @start: bit offset of the 8-bit value; must be a multiple of 8
> + *
> + * Returns the 8-bit value located at the @start bit offset within the @addr
> + * memory region.
> + */
> +static inline unsigned long bitmap_get_value8(const unsigned long *addr,
> + unsigned long start)
> +{
> + const size_t index = BIT_WORD(start);
> + const unsigned long offset = start % BITS_PER_LONG;
> +
> + return (addr[index] >> offset) & 0xFF;
> +}
> +
> +/**
> + * bitmap_set_value8 - set an 8-bit value within a memory region
find_and_set_value8()
?
> + * @addr: address to the bitmap memory region
> + * @value: the 8-bit value; values wider than 8 bits may clobber bitmap
> + * @start: bit offset of the 8-bit value; must be a multiple of 8
> + */
> +static inline void bitmap_set_value8(unsigned long *addr, unsigned long value,
> + unsigned long start)
> +{
> + const size_t index = BIT_WORD(start);
> + const unsigned long offset = start % BITS_PER_LONG;
> +
> + addr[index] &= ~(0xFF << offset);
> + addr[index] |= value << offset;
> +}
--
With Best Regards,
Andy Shevchenko
