On Mon, Mar 25, 2019 at 10:38:54AM +0100, Lukas Wunner wrote:
> 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
Is this the sort of implementation you had in mind:
offset = find_next_bit(addr, size, offset);
if (offset == size)
return size;
offset -= offset % 8;
*clump = bitmap_get_value8(addr, size, offset);
return offset;
Yes, this does seem more efficient to leverage the existing
find_next_bit function.
Should the offset and size parameters be redefined as unsigned long to
match the find_first_bit/find_next_bit function parameters?
William Breathitt Gray
