[PATCH 12/13] tools: sync lib/find_bit implementation
From: Yury Norov <yury.norov@gmail.com>
Date: 2021-03-16 01:55:41
Also in:
linux-arch, linux-m68k, lkml
Subsystem:
bitmap api, bitops api, the rest · Maintainers:
Yury Norov, Linus Torvalds
Add fast paths to find_*_bit() functions as per kernel implementation. Signed-off-by: Yury Norov <yury.norov@gmail.com> --- tools/include/asm-generic/bitops/find.h | 58 +++++++++++++++++++++++-- tools/lib/find_bit.c | 4 +- 2 files changed, 57 insertions(+), 5 deletions(-)
diff --git a/tools/include/asm-generic/bitops/find.h b/tools/include/asm-generic/bitops/find.h
index 9fe62d10b084..bf807af1503f 100644
--- a/tools/include/asm-generic/bitops/find.h
+++ b/tools/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 /**
@@ -20,6 +23,16 @@ static inline unsigned long find_next_bit(const unsigned long *addr, unsigned long size, unsigned long offset) { + if (small_const_nbits(size)) { + unsigned long val; + + if (unlikely(offset >= size)) + return size; + + val = *addr & GENMASK(size - 1, offset); + return val ? __ffs(val) : size; + } + return _find_next_bit(addr, NULL, size, offset, 0UL, 0); } #endif
@@ -40,6 +53,16 @@ unsigned long find_next_and_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, 0); } #endif
@@ -58,6 +81,16 @@ static inline unsigned long find_next_zero_bit(const unsigned long *addr, unsigned long size, unsigned long offset) { + if (small_const_nbits(size)) { + unsigned long val; + + if (unlikely(offset >= size)) + return size; + + val = *addr | ~GENMASK(size - 1, offset); + return val == ~0UL ? size : ffz(val); + } + return _find_next_bit(addr, NULL, size, offset, ~0UL, 0); } #endif
@@ -72,8 +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 & BITS_FIRST(size - 1); + + return val ? __ffs(val) : size; + } + + return _find_first_bit(addr, size); +} #endif /* find_first_bit */
@@ -87,7 +129,17 @@ 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. */ -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 | ~BITS_FIRST(size - 1); + + return val == ~0UL ? size : ffz(val); + } + + return _find_first_zero_bit(addr, size); +} #endif #endif /*_TOOLS_LINUX_ASM_GENERIC_BITOPS_FIND_H_ */
diff --git a/tools/lib/find_bit.c b/tools/lib/find_bit.c
index c3378b291205..a77884ca30ec 100644
--- a/tools/lib/find_bit.c
+++ b/tools/lib/find_bit.c@@ -83,7 +83,7 @@ unsigned long _find_next_bit(const unsigned long *addr1, /* * 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;
@@ -100,7 +100,7 @@ unsigned long find_first_bit(const unsigned long *addr, unsigned long size) /* * 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;
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2.25.1