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lib/find_bit: create find_first_zero_bit_le()

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find_first_zero_bit_le() is an alias to find_next_zero_bit_le(),
despite that 'next' is known to be slower than 'first' version.

Now that we have common FIND_FIRST_BIT() macro helper, it's trivial
to implement find_first_zero_bit_le() as a real function.

Reviewed-by: Valentin Schneider <vschneid@redhat.com>
Signed-off-by: Yury Norov <yury.norov@gmail.com>
This commit is contained in:
Yury Norov 2022-09-14 19:07:28 -07:00
parent 58414bbb58
commit 14a99e130f
2 changed files with 34 additions and 5 deletions
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23
include/linux/find.h
View File

@ -17,6 +17,10 @@ extern unsigned long _find_first_and_bit(const unsigned long *addr1,
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);
#ifdef __BIG_ENDIAN
unsigned long _find_first_zero_bit_le(const unsigned long *addr, unsigned long size);
#endif
#ifndef find_next_bit
/**
* find_next_bit - find the next set bit in a memory region
@ -251,6 +255,20 @@ unsigned long find_next_zero_bit_le(const void *addr, unsigned
}
#endif
#ifndef find_first_zero_bit_le
static inline
unsigned long find_first_zero_bit_le(const void *addr, unsigned long size)
{
if (small_const_nbits(size)) {
unsigned long val = swab(*(const unsigned long *)addr) | ~GENMASK(size - 1, 0);
return val == ~0UL ? size : ffz(val);
}
return _find_first_zero_bit_le(addr, size);
}
#endif
#ifndef find_next_bit_le
static inline
unsigned long find_next_bit_le(const void *addr, unsigned
@ -270,11 +288,6 @@ unsigned long find_next_bit_le(const void *addr, unsigned
}
#endif
#ifndef find_first_zero_bit_le
#define find_first_zero_bit_le(addr, size) \
find_next_zero_bit_le((addr), (size), 0)
#endif
#else
#error "Please fix <asm/byteorder.h>"
#endif

16
lib/find_bit.c
View File

@ -160,3 +160,19 @@ unsigned long find_next_clump8(unsigned long *clump, const unsigned long *addr,
return offset;
}
EXPORT_SYMBOL(find_next_clump8);
#ifdef __BIG_ENDIAN
#ifndef find_first_zero_bit_le
/*
* Find the first cleared bit in an LE memory region.
*/
unsigned long _find_first_zero_bit_le(const unsigned long *addr, unsigned long size)
{
return FIND_FIRST_BIT(~addr[idx], swab, size);
}
EXPORT_SYMBOL(_find_first_zero_bit_le);
#endif
#endif /* __BIG_ENDIAN */