leandrof/linux
1
0
Fork 0
forked from Minki/linux
Code Issues Pull Requests Packages Projects Releases Wiki Activity

tools: sync lib/find_bit implementation

Browse Source 
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>
This commit is contained in:
Yury Norov 2021-05-06 18:03:18 -07:00 committed by Linus Torvalds
parent 2cc7b6a44a
commit eaae7841ba
2 changed files with 57 additions and 5 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

58
tools/include/asm-generic/bitops/find.h
View File

@ -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_ */

4
tools/lib/find_bit.c
View File

@ -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;