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>
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@ -1813,7 +1813,7 @@ ext3_fsblk_t ext3_count_free_blocks(struct super_block *sb)
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brelse(bitmap_bh);
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brelse(bitmap_bh);
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printk("ext3_count_free_blocks: stored = "E3FSBLK
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printk("ext3_count_free_blocks: stored = "E3FSBLK
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", computed = "E3FSBLK", "E3FSBLK"\n",
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", computed = "E3FSBLK", "E3FSBLK"\n",
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le32_to_cpu(es->s_free_blocks_count),
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(ext3_fsblk_t)le32_to_cpu(es->s_free_blocks_count),
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desc_count, bitmap_count);
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desc_count, bitmap_count);
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return bitmap_count;
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return bitmap_count;
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#else
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#else
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@ -11,19 +11,9 @@
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#ifdef EXT3FS_DEBUG
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#ifdef EXT3FS_DEBUG
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static const int nibblemap[] = {4, 3, 3, 2, 3, 2, 2, 1, 3, 2, 2, 1, 2, 1, 1, 0};
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unsigned long ext3_count_free (struct buffer_head * map, unsigned int numchars)
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unsigned long ext3_count_free (struct buffer_head * map, unsigned int numchars)
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{
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{
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unsigned int i;
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return numchars * BITS_PER_BYTE - memweight(map->b_data, numchars);
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unsigned long sum = 0;
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if (!map)
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return (0);
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for (i = 0; i < numchars; i++)
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sum += nibblemap[map->b_data[i] & 0xf] +
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nibblemap[(map->b_data[i] >> 4) & 0xf];
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return (sum);
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}
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}
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#endif /* EXT3FS_DEBUG */
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#endif /* EXT3FS_DEBUG */
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