affs: use memweight()
Akinobu Mita [Mon, 30 Jul 2012 21:41:00 +0000 (14:41 -0700)]
Use memweight() to count the total number of bits set in memory area.

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

fs/affs/bitmap.c

index 6e0be43..a32246b 100644 (file)
 #include <linux/slab.h>
 #include "affs.h"
 
-/* This is, of course, shamelessly stolen from fs/minix */
-
-static const int nibblemap[] = { 0,1,1,2,1,2,2,3,1,2,2,3,2,3,3,4 };
-
-static u32
-affs_count_free_bits(u32 blocksize, const void *data)
-{
-       const u32 *map;
-       u32 free;
-       u32 tmp;
-
-       map = data;
-       free = 0;
-       for (blocksize /= 4; blocksize > 0; blocksize--) {
-               tmp = *map++;
-               while (tmp) {
-                       free += nibblemap[tmp & 0xf];
-                       tmp >>= 4;
-               }
-       }
-
-       return free;
-}
-
 u32
 affs_count_free_blocks(struct super_block *sb)
 {
@@ -317,7 +293,7 @@ int affs_init_bitmap(struct super_block *sb, int *flags)
                        goto out;
                }
                pr_debug("AFFS: read bitmap block %d: %d\n", blk, bm->bm_key);
-               bm->bm_free = affs_count_free_bits(sb->s_blocksize - 4, bh->b_data + 4);
+               bm->bm_free = memweight(bh->b_data + 4, sb->s_blocksize - 4);
 
                /* Don't try read the extension if this is the last block,
                 * but we also need the right bm pointer below
@@ -367,7 +343,7 @@ int affs_init_bitmap(struct super_block *sb, int *flags)
 
        /* recalculate bitmap count for last block */
        bm--;
-       bm->bm_free = affs_count_free_bits(sb->s_blocksize - 4, bh->b_data + 4);
+       bm->bm_free = memweight(bh->b_data + 4, sb->s_blocksize - 4);
 
 out:
        affs_brelse(bh);