Re: [PATCH v12 01/11] bitops: Introduce the for_each_set_clump8 macro

Lukas Wunner
2019-03-25T09:38:57Z

On Mon, Mar 25, 2019 at 03:22:23PM +0900, William Breathitt Gray wrote:
> +/**
> + * find_next_clump8 - find next 8-bit clump with set bits in a memory region
> + * @clump: location to store copy of found clump
> + * @addr: address to base the search on
> + * @offset: bit offset at which to start searching
> + * @size: bitmap size in number of bits
> + *
> + * Returns the bit offset for the next set clump; the found clump value is
> + * copied to the location pointed by @clump. If no bits are set, returns @size.
> + */
> +unsigned int find_next_clump8(unsigned long *const clump,
> + const unsigned long *const addr,
> + unsigned int offset, const unsigned int size)
> +{
> + for (; offset < size; offset += 8) {
> + *clump = bitmap_get_value8(addr, size, offset);
> + if (!*clump)
> + continue;
> +
> + return offset;
> + }
> +
> + return size;
> +}
> +EXPORT_SYMBOL(find_next_clump8);

Just use find_first_bit() / find_next_bit() to use optimized arch-specific
bitops instead of open-coding the iteration over the bitmap.

See max3191x_get_multiple() for an example.

Thanks,

Lukas