Commit eaae7841 authored by Yury Norov's avatar Yury Norov Committed by Linus Torvalds
Browse files

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: default avatarYury Norov <yury.norov@gmail.com>
Acked-by: default avatarRasmus 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: default avatarAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
parent 2cc7b6a4

tools/include/asm-generic/bitops/find.h

+55 −3
Original line number Diff line number Diff line
@@ -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_ */

tools/lib/find_bit.c

+2 −2
Original line number Diff line number Diff line
@@ -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;