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authorAkinobu Mita <akinobu.mita@gmail.com>2012-07-30 14:41:06 -0700
committerLinus Torvalds <torvalds@linux-foundation.org>2012-07-30 17:25:16 -0700
commit10d470849a7c6dd360e8ad4770160ad7af9adb4b (patch)
treed01812ca318a12e2a95a2bf46baa448f282fc234 /fs/ext3/bitmap.c
parentecd0afa3ced0ebf36901b53fd9ee431f8a34a161 (diff)
downloadlinux-10d470849a7c6dd360e8ad4770160ad7af9adb4b.tar.bz2
ext3: use memweight()
Convert ext3_count_free() to use memweight() instead of table lookup based counting clear bits implementation. This change only affects the code segments enabled by EXT3FS_DEBUG. Note that this memweight() call can't be replaced with a single bitmap_weight() call, although the pointer to the memory area is aligned to long-word boundary. Because the size of the memory area may not be a multiple of BITS_PER_LONG, then it returns wrong value on big-endian architecture. This also includes the following changes. - Remove unnecessary map == NULL check in ext3_count_free() which always takes non-null pointer as the memory area. - Fix printk format warning that only reveals with EXT3FS_DEBUG. Signed-off-by: Akinobu Mita <akinobu.mita@gmail.com> Acked-by: Jan Kara <jack@suse.cz> Cc: Andreas Dilger <adilger.kernel@dilger.ca> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Diffstat (limited to 'fs/ext3/bitmap.c')
-rw-r--r--fs/ext3/bitmap.c12
1 files changed, 1 insertions, 11 deletions
diff --git a/fs/ext3/bitmap.c b/fs/ext3/bitmap.c
index 909d13e26560..ef9c643e8e9d 100644
--- a/fs/ext3/bitmap.c
+++ b/fs/ext3/bitmap.c
@@ -11,19 +11,9 @@
#ifdef EXT3FS_DEBUG
-static const int nibblemap[] = {4, 3, 3, 2, 3, 2, 2, 1, 3, 2, 2, 1, 2, 1, 1, 0};
-
unsigned long ext3_count_free (struct buffer_head * map, unsigned int numchars)
{
- unsigned int i;
- unsigned long sum = 0;
-
- if (!map)
- return (0);
- for (i = 0; i < numchars; i++)
- sum += nibblemap[map->b_data[i] & 0xf] +
- nibblemap[(map->b_data[i] >> 4) & 0xf];
- return (sum);
+ return numchars * BITS_PER_BYTE - memweight(map->b_data, numchars);
}
#endif /* EXT3FS_DEBUG */