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: Akinobu Mita <akinobu.mita@gmail.com>
Acked-by: Jan Kara <jack@suse.cz>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

diff --git a/fs/ext2/balloc.c b/fs/ext2/balloc.c
index 1c361399886249070044987d8c2a93033202f445..376aa77f3ca7f330f2c6346053f2d1e49a990ebf 100644 (file)
--- a/fs/ext2/balloc.c
+++ b/fs/ext2/balloc.c
@@ -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 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  */

diff --git a/fs/ext2/ialloc.c b/fs/ext2/ialloc.c
index c13eb7b91a1100fa108a33275905d31ae35bfb02..8f370e012e613e73016856a9cab3c6257666a1a1 100644 (file)
--- a/fs/ext2/ialloc.c
+++ b/fs/ext2/ialloc.c
@@ -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;