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Commit ecd0afa3 authored by Akinobu Mita's avatar Akinobu Mita Committed by Linus Torvalds
Browse files

ext2: use memweight() 



Convert ext2_count_free() to use memweight() instead of table lookup
based counting clear bits implementation.  This change only affects the
code segments enabled by EXT2FS_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 ext2_count_free() which
  always takes non-null pointer as the memory area.

- Fix printk format warning that only reveals with EXT2FS_DEBUG.

Signed-off-by: default avatarAkinobu Mita <akinobu.mita@gmail.com>
Acked-by: default avatarJan Kara <jack@suse.cz>
Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
parent a75613ec

fs/ext2/balloc.c

+2 −12
Original line number Diff line number Diff line
@@ -1444,19 +1444,9 @@ ext2_fsblk_t ext2_new_block(struct inode *inode, unsigned long goal, int *errp) 


#ifdef EXT2FS_DEBUG



static const int nibblemap[] = {4, 3, 3, 2, 3, 2, 2, 1, 3, 2, 2, 1, 2, 1, 1, 0};



unsigned long ext2_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  /*  EXT2FS_DEBUG  */

fs/ext2/ialloc.c

+1 −0
Original line number Diff line number Diff line
@@ -644,6 +644,7 @@ unsigned long ext2_count_free_inodes (struct super_block * sb) 
	}

	brelse(bitmap_bh);

	printk("ext2_count_free_inodes: stored = %lu, computed = %lu, %lu\n",

		(unsigned long)

		percpu_counter_read(&EXT2_SB(sb)->s_freeinodes_counter),

		desc_count, bitmap_count);

	return desc_count;