Messages in this thread | | | Date | Thu, 18 Aug 2022 10:08:20 -0400 | From | Steven Rostedt <> | Subject | Re: [PATCH v2 1/5] bitops: Introduce find_next_andnot_bit() |
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On Wed, 17 Aug 2022 18:58:08 +0100 Valentin Schneider <vschneid@redhat.com> wrote:
> +#ifndef find_next_andnot_bit > +/** > + * find_next_andnot_bit - find the next set bit in one memory region > + * but not in the other > + * @addr1: The first address to base the search on > + * @addr2: The second address to base the search on > + * @size: The bitmap size in bits > + * @offset: The bitnumber to start searching at > + * > + * Returns the bit number for the next set bit > + * If no bits are set, returns @size.
Can we make the above documentation more descriptive. Because I read this three times, and I still have no idea what it does.
The tag line sounds like the nursery song "One of these things is not like the others".
-- Steve
> + */ > +static inline > +unsigned long find_next_andnot_bit(const unsigned long *addr1, > + const unsigned long *addr2, unsigned long size, > + unsigned long offset) > +{ > + if (small_const_nbits(size)) { > + unsigned long val; > + > + if (unlikely(offset >= size)) > + return size; > + > + val = *addr1 & ~*addr2 & GENMASK(size - 1, offset); > + return val ? __ffs(val) : size; > + } > + > + return _find_next_bit(addr1, addr2, size, offset, 0UL, ~0UL, 0); > } > #endif
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