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authorYury Norov <yury.norov@gmail.com>2021-05-06 18:03:18 -0700
committerLinus Torvalds <torvalds@linux-foundation.org>2021-05-06 19:24:12 -0700
commiteaae7841ba83bb42dcac3177dc65f8dd974e6c0b (patch)
treedadd6ed00af53e1ae2f0bdf09114604598961719 /tools/include
parent2cc7b6a44ac21d31b398b03f4845c53152070416 (diff)
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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@gmail.com Signed-off-by: Yury Norov <yury.norov@gmail.com> Acked-by: Rasmus Villemoes <linux@rasmusvillemoes.dk> Cc: Alexey Klimov <aklimov@redhat.com> Cc: Andy Shevchenko <andriy.shevchenko@linux.intel.com> Cc: Arnd Bergmann <arnd@arndb.de> Cc: David Sterba <dsterba@suse.com> Cc: Dennis Zhou <dennis@kernel.org> Cc: Geert Uytterhoeven <geert@linux-m68k.org> Cc: Jianpeng Ma <jianpeng.ma@intel.com> Cc: Joe Perches <joe@perches.com> Cc: John Paul Adrian Glaubitz <glaubitz@physik.fu-berlin.de> Cc: Josh Poimboeuf <jpoimboe@redhat.com> Cc: Rich Felker <dalias@libc.org> Cc: Stefano Brivio <sbrivio@redhat.com> Cc: Wei Yang <richard.weiyang@linux.alibaba.com> Cc: Wolfram Sang <wsa+renesas@sang-engineering.com> Cc: Yoshinori Sato <ysato@users.osdn.me> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Diffstat (limited to 'tools/include')
-rw-r--r--tools/include/asm-generic/bitops/find.h58
1 files changed, 55 insertions, 3 deletions
diff --git a/tools/include/asm-generic/bitops/find.h b/tools/include/asm-generic/bitops/find.h
index 9fe62d10b084..6481fd11012a 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 & 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(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 | ~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_ */