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    Subject[patch 15/44] 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: Akinobu Mita <mita@miraclelinux.com>
    include/asm-generic/bitops/ext2-non-atomic.h | 18 +++
    include/asm-generic/bitops/le.h | 126 +++++++++++++++++++++++++++
    2 files changed, 144 insertions(+)

    Index: 2.6-git/include/asm-generic/bitops/ext2-non-atomic.h
    ===================================================================
    --- /dev/null
    +++ 2.6-git/include/asm-generic/bitops/ext2-non-atomic.h
    @@ -0,0 +1,18 @@
    +#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_ */
    Index: 2.6-git/include/asm-generic/bitops/le.h
    ===================================================================
    --- /dev/null
    +++ 2.6-git/include/asm-generic/bitops/le.h
    @@ -0,0 +1,126 @@
    +#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)
    +
    +static __inline__ int generic_test_le_bit(unsigned long nr,
    + __const__ unsigned long *addr)
    +{
    + __const__ unsigned char *tmp = (__const__ unsigned char *) addr;
    + return (tmp[nr >> 3] >> (nr & 7)) & 1;
    +}
    +
    +#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)
    +
    +static __inline__ int generic_test_le_bit(unsigned long nr,
    + __const__ unsigned long *addr)
    +{
    + __const__ unsigned char *tmp = (__const__ unsigned char *) addr;
    + return (tmp[nr >> 3] >> (nr & 7)) & 1;
    +}
    +
    +#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))
    +
    +/* 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
    +}
    +
    +static __inline__ 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));
    +}
    +#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_ */
    --
    -
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