Messages in this thread Patch in this message | | | From | Yury Norov <> | Subject | [PATCH 4/5] lib/find_bit: create find_first_zero_bit_le() | Date | Thu, 28 Jul 2022 09:12:07 -0700 |
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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(), it's trivial to implement find_first_zero_bit_le() as a real function.
Signed-off-by: Yury Norov <yury.norov@gmail.com> --- include/linux/find.h | 20 +++++++++++++++----- lib/find_bit.c | 11 +++++++++++ 2 files changed, 26 insertions(+), 5 deletions(-)
diff --git a/include/linux/find.h b/include/linux/find.h index 3ace995d7079..8d326d1518f4 100644 --- a/include/linux/find.h +++ b/include/linux/find.h @@ -19,6 +19,7 @@ unsigned long _find_next_zero_bit_le(const void *addr, unsigned long size, unsigned long offset); unsigned long _find_next_bit_le(const void *addr, unsigned long size, unsigned long offset); +unsigned long _find_first_zero_bit_le(const unsigned long *addr, unsigned long size); #endif extern unsigned long _find_first_bit(const unsigned long *addr, unsigned long size); extern unsigned long _find_first_and_bit(const unsigned long *addr1, @@ -260,6 +261,20 @@ 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 unsigned long *addr, unsigned long size) +{ + if (small_const_nbits(size)) { + unsigned long val = swab(*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 @@ -279,11 +294,6 @@ 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 diff --git a/lib/find_bit.c b/lib/find_bit.c index d207d1699834..a56872611a59 100644 --- a/lib/find_bit.c +++ b/lib/find_bit.c @@ -119,6 +119,17 @@ EXPORT_SYMBOL(_find_next_zero_bit); #endif #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, NULL, size, ~0UL, true); +} +EXPORT_SYMBOL(_find_first_zero_bit_le); +#endif + #ifndef find_next_zero_bit_le unsigned long _find_next_zero_bit_le(const void *addr, unsigned long size, unsigned long offset) -- 2.34.1
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