On Thu, Apr 1, 2021 at 3:41 AM Yury Norov <yury.no...@gmail.com> wrote: > > Similarly to bitmap functions, users would benefit if we'll handle > a case of small-size bitmaps that fit into a single word. > > While here, move the find_last_bit() declaration to bitops/find.h > where other find_*_bit() functions sit.
Acked-by: Andy Shevchenko <andy.shevche...@gmail.com> > Signed-off-by: Yury Norov <yury.no...@gmail.com> > Acked-by: Rasmus Villemoes <li...@rasmusvillemoes.dk> > --- > include/asm-generic/bitops/find.h | 50 ++++++++++++++++++++++++++++--- > include/linux/bitops.h | 12 -------- > lib/find_bit.c | 12 ++++---- > 3 files changed, 52 insertions(+), 22 deletions(-) > > diff --git a/include/asm-generic/bitops/find.h > b/include/asm-generic/bitops/find.h > index 4148c74a1e4d..0d132ee2a291 100644 > --- a/include/asm-generic/bitops/find.h > +++ b/include/asm-generic/bitops/find.h > @@ -5,6 +5,9 @@ > 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); > +extern unsigned long _find_first_bit(const unsigned long *addr, unsigned > long size); > +extern unsigned long _find_first_zero_bit(const unsigned long *addr, > unsigned long size); > +extern unsigned long _find_last_bit(const unsigned long *addr, unsigned long > size); > > #ifndef find_next_bit > /** > @@ -102,8 +105,17 @@ unsigned long find_next_zero_bit(const unsigned long > *addr, unsigned long size, > * Returns the bit number of the first set bit. > * If no bits are set, returns @size. > */ > -extern unsigned long find_first_bit(const unsigned long *addr, > - unsigned long size); > +static inline > +unsigned long find_first_bit(const unsigned long *addr, unsigned long size) > +{ > + if (small_const_nbits(size)) { > + unsigned long val = *addr & GENMASK(size - 1, 0); > + > + return val ? __ffs(val) : size; > + } > + > + return _find_first_bit(addr, size); > +} > > /** > * find_first_zero_bit - find the first cleared bit in a memory region > @@ -113,8 +125,17 @@ extern unsigned long find_first_bit(const unsigned long > *addr, > * Returns the bit number of the first cleared bit. > * If no bits are zero, returns @size. > */ > -extern unsigned long find_first_zero_bit(const unsigned long *addr, > - unsigned long size); > +static inline > +unsigned long find_first_zero_bit(const unsigned long *addr, unsigned long > size) > +{ > + if (small_const_nbits(size)) { > + unsigned long val = *addr | ~GENMASK(size - 1, 0); > + > + return val == ~0UL ? size : ffz(val); > + } > + > + return _find_first_zero_bit(addr, size); > +} > #else /* CONFIG_GENERIC_FIND_FIRST_BIT */ > > #ifndef find_first_bit > @@ -126,6 +147,27 @@ extern unsigned long find_first_zero_bit(const unsigned > long *addr, > > #endif /* CONFIG_GENERIC_FIND_FIRST_BIT */ > > +#ifndef find_last_bit > +/** > + * find_last_bit - find the last set bit in a memory region > + * @addr: The address to start the search at > + * @size: The number of bits to search > + * > + * Returns the bit number of the last set bit, or size. > + */ > +static inline > +unsigned long find_last_bit(const unsigned long *addr, unsigned long size) > +{ > + if (small_const_nbits(size)) { > + unsigned long val = *addr & GENMASK(size - 1, 0); > + > + return val ? __fls(val) : size; > + } > + > + return _find_last_bit(addr, size); > +} > +#endif > + > /** > * find_next_clump8 - find next 8-bit clump with set bits in a memory region > * @clump: location to store copy of found clump > diff --git a/include/linux/bitops.h b/include/linux/bitops.h > index a5a48303b0f1..26bf15e6cd35 100644 > --- a/include/linux/bitops.h > +++ b/include/linux/bitops.h > @@ -286,17 +286,5 @@ static __always_inline void __assign_bit(long nr, > volatile unsigned long *addr, > }) > #endif > > -#ifndef find_last_bit > -/** > - * find_last_bit - find the last set bit in a memory region > - * @addr: The address to start the search at > - * @size: The number of bits to search > - * > - * Returns the bit number of the last set bit, or size. > - */ > -extern unsigned long find_last_bit(const unsigned long *addr, > - unsigned long size); > -#endif > - > #endif /* __KERNEL__ */ > #endif > diff --git a/lib/find_bit.c b/lib/find_bit.c > index b03a101367f8..0f8e2e369b1d 100644 > --- a/lib/find_bit.c > +++ b/lib/find_bit.c > @@ -75,7 +75,7 @@ EXPORT_SYMBOL(_find_next_bit); > /* > * Find the first set bit in a memory region. > */ > -unsigned long find_first_bit(const unsigned long *addr, unsigned long size) > +unsigned long _find_first_bit(const unsigned long *addr, unsigned long size) > { > unsigned long idx; > > @@ -86,14 +86,14 @@ unsigned long find_first_bit(const unsigned long *addr, > unsigned long size) > > return size; > } > -EXPORT_SYMBOL(find_first_bit); > +EXPORT_SYMBOL(_find_first_bit); > #endif > > #ifndef find_first_zero_bit > /* > * Find the first cleared bit in a memory region. > */ > -unsigned long find_first_zero_bit(const unsigned long *addr, unsigned long > size) > +unsigned long _find_first_zero_bit(const unsigned long *addr, unsigned long > size) > { > unsigned long idx; > > @@ -104,11 +104,11 @@ unsigned long find_first_zero_bit(const unsigned long > *addr, unsigned long size) > > return size; > } > -EXPORT_SYMBOL(find_first_zero_bit); > +EXPORT_SYMBOL(_find_first_zero_bit); > #endif > > #ifndef find_last_bit > -unsigned long find_last_bit(const unsigned long *addr, unsigned long size) > +unsigned long _find_last_bit(const unsigned long *addr, unsigned long size) > { > if (size) { > unsigned long val = BITMAP_LAST_WORD_MASK(size); > @@ -124,7 +124,7 @@ unsigned long find_last_bit(const unsigned long *addr, > unsigned long size) > } > return size; > } > -EXPORT_SYMBOL(find_last_bit); > +EXPORT_SYMBOL(_find_last_bit); > #endif > > unsigned long find_next_clump8(unsigned long *clump, const unsigned long > *addr, > -- > 2.25.1 > -- With Best Regards, Andy Shevchenko