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author | Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com> | 2008-01-29 05:58:27 +0100 |
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committer | Theodore Ts'o <tytso@mit.edu> | 2008-01-29 05:58:27 +0100 |
commit | aa02ad67d9b308290fde390682cd039b29f7ab85 (patch) | |
tree | 1ebf910ab16e6081b5dd3ca526973f09cfd065c4 /lib/find_next_bit.c | |
parent | ext4: fix up EXT4FS_DEBUG builds (diff) | |
download | linux-aa02ad67d9b308290fde390682cd039b29f7ab85.tar.xz linux-aa02ad67d9b308290fde390682cd039b29f7ab85.zip |
ext4: Add ext4_find_next_bit()
This function is used by the ext4 multi block allocator patches.
Also add generic_find_next_le_bit
Signed-off-by: Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com>
Cc: <linux-ext4@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Diffstat (limited to 'lib/find_next_bit.c')
-rw-r--r-- | lib/find_next_bit.c | 43 |
1 files changed, 43 insertions, 0 deletions
diff --git a/lib/find_next_bit.c b/lib/find_next_bit.c index bda0d71a2514..78ccd73a8841 100644 --- a/lib/find_next_bit.c +++ b/lib/find_next_bit.c @@ -178,4 +178,47 @@ found_middle_swap: EXPORT_SYMBOL(generic_find_next_zero_le_bit); +unsigned long generic_find_next_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 << 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)) { + tmp = *(p++); + if (tmp) + goto found_middle_swap; + result += BITS_PER_LONG; + size -= BITS_PER_LONG; + } + if (!size) + return result; + tmp = ext2_swabp(p); +found_first: + tmp &= (~0UL >> (BITS_PER_LONG - size)); + if (tmp == 0UL) /* Are any bits set? */ + return result + size; /* Nope. */ +found_middle: + return result + __ffs(tmp); + +found_middle_swap: + return result + __ffs(ext2_swab(tmp)); +} +EXPORT_SYMBOL(generic_find_next_le_bit); #endif /* __BIG_ENDIAN */ |