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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: Akinobu Mita <mita@miraclelinux.com> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
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18
include/asm-generic/bitops/ext2-non-atomic.h
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18
include/asm-generic/bitops/ext2-non-atomic.h
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@ -0,0 +1,18 @@
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#ifndef _ASM_GENERIC_BITOPS_EXT2_NON_ATOMIC_H_
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#define _ASM_GENERIC_BITOPS_EXT2_NON_ATOMIC_H_
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#include <asm-generic/bitops/le.h>
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#define ext2_set_bit(nr,addr) \
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generic___test_and_set_le_bit((nr),(unsigned long *)(addr))
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#define ext2_clear_bit(nr,addr) \
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generic___test_and_clear_le_bit((nr),(unsigned long *)(addr))
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#define ext2_test_bit(nr,addr) \
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generic_test_le_bit((nr),(unsigned long *)(addr))
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#define ext2_find_first_zero_bit(addr, size) \
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generic_find_first_zero_le_bit((unsigned long *)(addr), (size))
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#define ext2_find_next_zero_bit(addr, size, off) \
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generic_find_next_zero_le_bit((unsigned long *)(addr), (size), (off))
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#endif /* _ASM_GENERIC_BITOPS_EXT2_NON_ATOMIC_H_ */
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53
include/asm-generic/bitops/le.h
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include/asm-generic/bitops/le.h
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@ -0,0 +1,53 @@
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#ifndef _ASM_GENERIC_BITOPS_LE_H_
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#define _ASM_GENERIC_BITOPS_LE_H_
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#include <asm/types.h>
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#include <asm/byteorder.h>
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#define BITOP_WORD(nr) ((nr) / BITS_PER_LONG)
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#define BITOP_LE_SWIZZLE ((BITS_PER_LONG-1) & ~0x7)
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#if defined(__LITTLE_ENDIAN)
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#define generic_test_le_bit(nr, addr) test_bit(nr, addr)
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#define generic___set_le_bit(nr, addr) __set_bit(nr, addr)
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#define generic___clear_le_bit(nr, addr) __clear_bit(nr, addr)
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#define generic_test_and_set_le_bit(nr, addr) test_and_set_bit(nr, addr)
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#define generic_test_and_clear_le_bit(nr, addr) test_and_clear_bit(nr, addr)
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#define generic___test_and_set_le_bit(nr, addr) __test_and_set_bit(nr, addr)
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#define generic___test_and_clear_le_bit(nr, addr) __test_and_clear_bit(nr, addr)
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#define generic_find_next_zero_le_bit(addr, size, offset) find_next_zero_bit(addr, size, offset)
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#elif defined(__BIG_ENDIAN)
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#define generic_test_le_bit(nr, addr) \
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test_bit((nr) ^ BITOP_LE_SWIZZLE, (addr))
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#define generic___set_le_bit(nr, addr) \
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__set_bit((nr) ^ BITOP_LE_SWIZZLE, (addr))
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#define generic___clear_le_bit(nr, addr) \
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__clear_bit((nr) ^ BITOP_LE_SWIZZLE, (addr))
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#define generic_test_and_set_le_bit(nr, addr) \
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test_and_set_bit((nr) ^ BITOP_LE_SWIZZLE, (addr))
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#define generic_test_and_clear_le_bit(nr, addr) \
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test_and_clear_bit((nr) ^ BITOP_LE_SWIZZLE, (addr))
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#define generic___test_and_set_le_bit(nr, addr) \
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__test_and_set_bit((nr) ^ BITOP_LE_SWIZZLE, (addr))
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#define generic___test_and_clear_le_bit(nr, addr) \
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__test_and_clear_bit((nr) ^ BITOP_LE_SWIZZLE, (addr))
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extern unsigned long generic_find_next_zero_le_bit(const unsigned long *addr,
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unsigned long size, unsigned long offset);
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#else
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#error "Please fix <asm/byteorder.h>"
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#endif
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#define generic_find_first_zero_le_bit(addr, size) \
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generic_find_next_zero_le_bit((addr), (size), 0)
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#endif /* _ASM_GENERIC_BITOPS_LE_H_ */
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@ -12,6 +12,7 @@
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#include <linux/bitops.h>
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#include <linux/module.h>
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#include <asm/types.h>
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#include <asm/byteorder.h>
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#define BITOP_WORD(nr) ((nr) / BITS_PER_LONG)
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@ -106,3 +107,75 @@ found_middle:
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}
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EXPORT_SYMBOL(find_next_zero_bit);
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#ifdef __BIG_ENDIAN
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/* include/linux/byteorder does not support "unsigned long" type */
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static inline unsigned long ext2_swabp(const unsigned long * x)
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{
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#if BITS_PER_LONG == 64
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return (unsigned long) __swab64p((u64 *) x);
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#elif BITS_PER_LONG == 32
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return (unsigned long) __swab32p((u32 *) x);
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#else
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#error BITS_PER_LONG not defined
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#endif
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}
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/* include/linux/byteorder doesn't support "unsigned long" type */
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static inline unsigned long ext2_swab(const unsigned long y)
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{
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#if BITS_PER_LONG == 64
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return (unsigned long) __swab64((u64) y);
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#elif BITS_PER_LONG == 32
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return (unsigned long) __swab32((u32) y);
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#else
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#error BITS_PER_LONG not defined
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#endif
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}
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unsigned long generic_find_next_zero_le_bit(const unsigned long *addr, unsigned
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long size, unsigned long offset)
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{
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const unsigned long *p = addr + BITOP_WORD(offset);
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unsigned long result = offset & ~(BITS_PER_LONG - 1);
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unsigned long tmp;
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if (offset >= size)
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return size;
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size -= result;
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offset &= (BITS_PER_LONG - 1UL);
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if (offset) {
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tmp = ext2_swabp(p++);
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tmp |= (~0UL >> (BITS_PER_LONG - offset));
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if (size < BITS_PER_LONG)
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goto found_first;
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if (~tmp)
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goto found_middle;
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size -= BITS_PER_LONG;
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result += BITS_PER_LONG;
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}
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while (size & ~(BITS_PER_LONG - 1)) {
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if (~(tmp = *(p++)))
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goto found_middle_swap;
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result += BITS_PER_LONG;
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size -= BITS_PER_LONG;
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}
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if (!size)
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return result;
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tmp = ext2_swabp(p);
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found_first:
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tmp |= ~0UL << size;
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if (tmp == ~0UL) /* Are any bits zero? */
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return result + size; /* Nope. Skip ffz */
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found_middle:
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return result + ffz(tmp);
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found_middle_swap:
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return result + ffz(ext2_swab(tmp));
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}
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EXPORT_SYMBOL(generic_find_next_zero_le_bit);
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#endif /* __BIG_ENDIAN */
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