On Thu, Aug 25, 2022 at 07:12:04PM +0100, Valentin Schneider wrote: > In preparation of introducing for_each_cpu_andnot(), add a variant of > find_next_bit() that negate the bits in @addr2 when ANDing them with the > bits in @addr1. > > Note that the _find_next_bit() @invert argument now gets split into two: > @invert1 for words in @addr1, @invert2 for words in @addr2. The only > current users of _find_next_bit() with @invert set are: > o find_next_zero_bit() > o find_next_zero_bit_le() > and neither of these pass an @addr2, so the conversion is straightforward. > > Signed-off-by: Valentin Schneider <vschneid@xxxxxxxxxx> Have you seen this series? https://lore.kernel.org/lkml/YwaXvphVpy5A7fSs@yury-laptop/t/ It will significantly simplify your work for adding the find_next_andnot_bit(). If you wait a week or so, you'll most likely find it in -next. Thanks, Yury > --- > include/linux/find.h | 44 ++++++++++++++++++++++++++++++++++++++------ > lib/find_bit.c | 23 ++++++++++++----------- > 2 files changed, 50 insertions(+), 17 deletions(-) > > diff --git a/include/linux/find.h b/include/linux/find.h > index 424ef67d4a42..a195cf0a8bab 100644 > --- a/include/linux/find.h > +++ b/include/linux/find.h > @@ -10,7 +10,8 @@ > > extern unsigned long _find_next_bit(const unsigned long *addr1, > const unsigned long *addr2, unsigned long nbits, > - unsigned long start, unsigned long invert, unsigned long le); > + unsigned long start, unsigned long invert1, unsigned long invert2, > + unsigned long le); > extern unsigned long _find_first_bit(const unsigned long *addr, unsigned long size); > extern unsigned long _find_first_and_bit(const unsigned long *addr1, > const unsigned long *addr2, unsigned long size); > @@ -41,7 +42,7 @@ unsigned long find_next_bit(const unsigned long *addr, unsigned long size, > return val ? __ffs(val) : size; > } > > - return _find_next_bit(addr, NULL, size, offset, 0UL, 0); > + return _find_next_bit(addr, NULL, size, offset, 0UL, 0UL, 0); > } > #endif > > @@ -71,7 +72,38 @@ unsigned long find_next_and_bit(const unsigned long *addr1, > return val ? __ffs(val) : size; > } > > - return _find_next_bit(addr1, addr2, size, offset, 0UL, 0); > + return _find_next_bit(addr1, addr2, size, offset, 0UL, 0UL, 0); > +} > +#endif > + > +#ifndef find_next_andnot_bit > +/** > + * find_next_andnot_bit - find the next bit in *addr1 excluding all the bits > + * in *addr2 > + * @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. > + */ > +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 > > @@ -99,7 +131,7 @@ unsigned long find_next_zero_bit(const unsigned long *addr, unsigned long size, > return val == ~0UL ? size : ffz(val); > } > > - return _find_next_bit(addr, NULL, size, offset, ~0UL, 0); > + return _find_next_bit(addr, NULL, size, offset, ~0UL, 0UL, 0); > } > #endif > > @@ -247,7 +279,7 @@ unsigned long find_next_zero_bit_le(const void *addr, unsigned > return val == ~0UL ? size : ffz(val); > } > > - return _find_next_bit(addr, NULL, size, offset, ~0UL, 1); > + return _find_next_bit(addr, NULL, size, offset, ~0UL, 0UL, 1); > } > #endif > > @@ -266,7 +298,7 @@ unsigned long find_next_bit_le(const void *addr, unsigned > return val ? __ffs(val) : size; > } > > - return _find_next_bit(addr, NULL, size, offset, 0UL, 1); > + return _find_next_bit(addr, NULL, size, offset, 0UL, 0UL, 1); > } > #endif > > diff --git a/lib/find_bit.c b/lib/find_bit.c > index 1b8e4b2a9cba..c46b66d7d2b4 100644 > --- a/lib/find_bit.c > +++ b/lib/find_bit.c > @@ -21,27 +21,29 @@ > > #if !defined(find_next_bit) || !defined(find_next_zero_bit) || \ > !defined(find_next_bit_le) || !defined(find_next_zero_bit_le) || \ > - !defined(find_next_and_bit) > + !defined(find_next_and_bit) || !defined(find_next_andnot_bit) > /* > * This is a common helper function for find_next_bit, find_next_zero_bit, and > * find_next_and_bit. The differences are: > - * - The "invert" argument, which is XORed with each fetched word before > - * searching it for one bits. > * - The optional "addr2", which is anded with "addr1" if present. > + * - The "invert" arguments, which are XORed with each fetched word (invert1 > + * for words in addr1, invert2 for those in addr2) before searching it for > + * one bits. > */ > unsigned long _find_next_bit(const unsigned long *addr1, > - const unsigned long *addr2, unsigned long nbits, > - unsigned long start, unsigned long invert, unsigned long le) > + const unsigned long *addr2, > + unsigned long nbits, unsigned long start, > + unsigned long invert1, unsigned long invert2, > + unsigned long le) > { > unsigned long tmp, mask; > > if (unlikely(start >= nbits)) > return nbits; > > - tmp = addr1[start / BITS_PER_LONG]; > + tmp = addr1[start / BITS_PER_LONG] ^ invert1; > if (addr2) > - tmp &= addr2[start / BITS_PER_LONG]; > - tmp ^= invert; > + tmp &= addr2[start / BITS_PER_LONG] ^ invert2; > > /* Handle 1st word. */ > mask = BITMAP_FIRST_WORD_MASK(start); > @@ -57,10 +59,9 @@ unsigned long _find_next_bit(const unsigned long *addr1, > if (start >= nbits) > return nbits; > > - tmp = addr1[start / BITS_PER_LONG]; > + tmp = addr1[start / BITS_PER_LONG] ^ invert1; > if (addr2) > - tmp &= addr2[start / BITS_PER_LONG]; > - tmp ^= invert; > + tmp &= addr2[start / BITS_PER_LONG] ^ invert2; > } > > if (le) > -- > 2.31.1
