The patch titled
Subject: tools: sync lib/find_bit implementation
has been added to the -mm tree. Its filename is
tools-sync-lib-find_bit-implementation.patch
This patch should soon appear at
https://ozlabs.org/~akpm/mmots/broken-out/tools-sync-lib-find_bit-implementation.patch
and later at
https://ozlabs.org/~akpm/mmotm/broken-out/tools-sync-lib-find_bit-implementation.patch
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------------------------------------------------------
From: Yury Norov <yury.norov@xxxxxxxxx>
Subject: tools: sync lib/find_bit implementation
Add fast paths to find_*_bit() functions as per kernel implementation.
Link: https://lkml.kernel.org/r/20210401003153.97325-12-yury.norov@xxxxxxxxx
Signed-off-by: Yury Norov <yury.norov@xxxxxxxxx>
Acked-by: Rasmus Villemoes <linux@xxxxxxxxxxxxxxxxxx>
Cc: Alexey Klimov <aklimov@xxxxxxxxxx>
Cc: Andy Shevchenko <andriy.shevchenko@xxxxxxxxxxxxxxx>
Cc: Arnd Bergmann <arnd@xxxxxxxx>
Cc: David Sterba <dsterba@xxxxxxxx>
Cc: Dennis Zhou <dennis@xxxxxxxxxx>
Cc: Geert Uytterhoeven <geert@xxxxxxxxxxxxxx>
Cc: Jianpeng Ma <jianpeng.ma@xxxxxxxxx>
Cc: Joe Perches <joe@xxxxxxxxxxx>
Cc: John Paul Adrian Glaubitz <glaubitz@xxxxxxxxxxxxxxxxxxx>
Cc: Josh Poimboeuf <jpoimboe@xxxxxxxxxx>
Cc: Rich Felker <dalias@xxxxxxxx>
Cc: Stefano Brivio <sbrivio@xxxxxxxxxx>
Cc: Wei Yang <richard.weiyang@xxxxxxxxxxxxxxxxx>
Cc: Wolfram Sang <wsa+renesas@xxxxxxxxxxxxxxxxxxxx>
Cc: Yoshinori Sato <ysato@xxxxxxxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
tools/include/asm-generic/bitops/find.h | 58 ++++++++++++++++++++--
tools/lib/find_bit.c | 4 -
2 files changed, 57 insertions(+), 5 deletions(-)
--- a/tools/include/asm-generic/bitops/find.h~tools-sync-lib-find_bit-implementation
+++ a/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 un
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 u
* 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);
+}
#endif /* find_first_bit */
@@ -87,7 +129,17 @@ extern unsigned long find_first_bit(cons
* 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 | ~GENMASK(size - 1, 0);
+
+ return val == ~0UL ? size : ffz(val);
+ }
+
+ return _find_first_zero_bit(addr, size);
+}
#endif
#endif /*_TOOLS_LINUX_ASM_GENERIC_BITOPS_FIND_H_ */
--- a/tools/lib/find_bit.c~tools-sync-lib-find_bit-implementation
+++ a/tools/lib/find_bit.c
@@ -83,7 +83,7 @@ unsigned long _find_next_bit(const unsig
/*
* 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 unsig
/*
* 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;
_
Patches currently in -mm which might be from yury.norov@xxxxxxxxx are
tools-disable-wno-type-limits.patch
tools-bitmap-sync-function-declarations-with-the-kernel.patch
tools-sync-bitmap_last_word_mask-macro-with-the-kernel.patch
arch-rearrange-headers-inclusion-order-in-asm-bitops-for-m68k-and-sh.patch
lib-extend-the-scope-of-small_const_nbits-macro.patch
tools-sync-small_const_nbits-macro-with-the-kernel.patch
lib-inline-_find_next_bit-wrappers.patch
tools-sync-find_next_bit-implementation.patch
lib-add-fast-path-for-find_next__bit.patch
lib-add-fast-path-for-find_first__bit-and-find_last_bit.patch
tools-sync-lib-find_bit-implementation.patch
maintainers-add-entry-for-the-bitmap-api.patch
