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Commit 930ae745 authored by Akinobu Mita's avatar Akinobu Mita Committed by Linus Torvalds
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[PATCH] bitops: generic ext2_{set,clear,test,find_first_zero,find_next_zero}_bit() 



This patch introduces the C-language equivalents of the functions below:

int ext2_set_bit(int nr, volatile unsigned long *addr);
int ext2_clear_bit(int nr, volatile unsigned long *addr);
int ext2_test_bit(int nr, const volatile unsigned long *addr);
unsigned long ext2_find_first_zero_bit(const unsigned long *addr,
                                       unsigned long size);
unsinged long ext2_find_next_zero_bit(const unsigned long *addr,
                                      unsigned long size);

In include/asm-generic/bitops/ext2-non-atomic.h

This code largely copied from:

include/asm-powerpc/bitops.h
include/asm-parisc/bitops.h

Signed-off-by: default avatarAkinobu Mita <mita@miraclelinux.com>
Signed-off-by: default avatarAndrew Morton <akpm@osdl.org>
Signed-off-by: default avatarLinus Torvalds <torvalds@osdl.org>
parent a54baa14

include/asm-generic/bitops/ext2-non-atomic.h

0 → 100644
+18 −0
Original line number Diff line number Diff line 
#ifndef _ASM_GENERIC_BITOPS_EXT2_NON_ATOMIC_H_

#define _ASM_GENERIC_BITOPS_EXT2_NON_ATOMIC_H_



#include <asm-generic/bitops/le.h>



#define ext2_set_bit(nr,addr)	\

	generic___test_and_set_le_bit((nr),(unsigned long *)(addr))

#define ext2_clear_bit(nr,addr)	\

	generic___test_and_clear_le_bit((nr),(unsigned long *)(addr))



#define ext2_test_bit(nr,addr)	\

	generic_test_le_bit((nr),(unsigned long *)(addr))

#define ext2_find_first_zero_bit(addr, size) \

	generic_find_first_zero_le_bit((unsigned long *)(addr), (size))

#define ext2_find_next_zero_bit(addr, size, off) \

	generic_find_next_zero_le_bit((unsigned long *)(addr), (size), (off))



#endif /* _ASM_GENERIC_BITOPS_EXT2_NON_ATOMIC_H_ */

include/asm-generic/bitops/le.h

0 → 100644
+53 −0
Original line number Diff line number Diff line 
#ifndef _ASM_GENERIC_BITOPS_LE_H_

#define _ASM_GENERIC_BITOPS_LE_H_



#include <asm/types.h>

#include <asm/byteorder.h>



#define BITOP_WORD(nr)		((nr) / BITS_PER_LONG)

#define BITOP_LE_SWIZZLE	((BITS_PER_LONG-1) & ~0x7)



#if defined(__LITTLE_ENDIAN)



#define generic_test_le_bit(nr, addr) test_bit(nr, addr)

#define generic___set_le_bit(nr, addr) __set_bit(nr, addr)

#define generic___clear_le_bit(nr, addr) __clear_bit(nr, addr)



#define generic_test_and_set_le_bit(nr, addr) test_and_set_bit(nr, addr)

#define generic_test_and_clear_le_bit(nr, addr) test_and_clear_bit(nr, addr)



#define generic___test_and_set_le_bit(nr, addr) __test_and_set_bit(nr, addr)

#define generic___test_and_clear_le_bit(nr, addr) __test_and_clear_bit(nr, addr)



#define generic_find_next_zero_le_bit(addr, size, offset) find_next_zero_bit(addr, size, offset)



#elif defined(__BIG_ENDIAN)



#define generic_test_le_bit(nr, addr) \

	test_bit((nr) ^ BITOP_LE_SWIZZLE, (addr))

#define generic___set_le_bit(nr, addr) \

	__set_bit((nr) ^ BITOP_LE_SWIZZLE, (addr))

#define generic___clear_le_bit(nr, addr) \

	__clear_bit((nr) ^ BITOP_LE_SWIZZLE, (addr))



#define generic_test_and_set_le_bit(nr, addr) \

	test_and_set_bit((nr) ^ BITOP_LE_SWIZZLE, (addr))

#define generic_test_and_clear_le_bit(nr, addr) \

	test_and_clear_bit((nr) ^ BITOP_LE_SWIZZLE, (addr))



#define generic___test_and_set_le_bit(nr, addr) \

	__test_and_set_bit((nr) ^ BITOP_LE_SWIZZLE, (addr))

#define generic___test_and_clear_le_bit(nr, addr) \

	__test_and_clear_bit((nr) ^ BITOP_LE_SWIZZLE, (addr))



extern unsigned long generic_find_next_zero_le_bit(const unsigned long *addr,

		unsigned long size, unsigned long offset);



#else

#error "Please fix <asm/byteorder.h>"

#endif



#define generic_find_first_zero_le_bit(addr, size) \

        generic_find_next_zero_le_bit((addr), (size), 0)



#endif /* _ASM_GENERIC_BITOPS_LE_H_ */

lib/find_next_bit.c

+73 −0
Original line number Diff line number Diff line
@@ -12,6 +12,7 @@ 
#include <linux/bitops.h>

#include <linux/module.h>

#include <asm/types.h>

#include <asm/byteorder.h>



#define BITOP_WORD(nr)		((nr) / BITS_PER_LONG)
@@ -106,3 +107,75 @@ unsigned long find_next_zero_bit(const unsigned long *addr, unsigned long size, 
}



EXPORT_SYMBOL(find_next_zero_bit);



#ifdef __BIG_ENDIAN



/* include/linux/byteorder does not support "unsigned long" type */

static inline unsigned long ext2_swabp(const unsigned long * x)

{

#if BITS_PER_LONG == 64

	return (unsigned long) __swab64p((u64 *) x);

#elif BITS_PER_LONG == 32

	return (unsigned long) __swab32p((u32 *) x);

#else

#error BITS_PER_LONG not defined

#endif

}



/* include/linux/byteorder doesn't support "unsigned long" type */

static inline unsigned long ext2_swab(const unsigned long y)

{

#if BITS_PER_LONG == 64

	return (unsigned long) __swab64((u64) y);

#elif BITS_PER_LONG == 32

	return (unsigned long) __swab32((u32) y);

#else

#error BITS_PER_LONG not defined

#endif

}



unsigned long generic_find_next_zero_le_bit(const unsigned long *addr, unsigned

		long size, unsigned long offset)

{

	const unsigned long *p = addr + BITOP_WORD(offset);

	unsigned long result = offset & ~(BITS_PER_LONG - 1);

	unsigned long tmp;



	if (offset >= size)

		return size;

	size -= result;

	offset &= (BITS_PER_LONG - 1UL);

	if (offset) {

		tmp = ext2_swabp(p++);

		tmp |= (~0UL >> (BITS_PER_LONG - offset));

		if (size < BITS_PER_LONG)

			goto found_first;

		if (~tmp)

			goto found_middle;

		size -= BITS_PER_LONG;

		result += BITS_PER_LONG;

	}



	while (size & ~(BITS_PER_LONG - 1)) {

		if (~(tmp = *(p++)))

			goto found_middle_swap;

		result += BITS_PER_LONG;

		size -= BITS_PER_LONG;

	}

	if (!size)

		return result;

	tmp = ext2_swabp(p);

found_first:

	tmp |= ~0UL << size;

	if (tmp == ~0UL)	/* Are any bits zero? */

		return result + size; /* Nope. Skip ffz */

found_middle:

	return result + ffz(tmp);



found_middle_swap:

	return result + ffz(ext2_swab(tmp));

}



EXPORT_SYMBOL(generic_find_next_zero_le_bit);



#endif /* __BIG_ENDIAN */