From ecd0afa3ced0ebf36901b53fd9ee431f8a34a161 Mon Sep 17 00:00:00 2001 From: Akinobu Mita Date: Mon, 30 Jul 2012 14:41:05 -0700 Subject: 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 Acked-by: Jan Kara Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- fs/ext2/balloc.c | 14 ++------------ 1 file changed, 2 insertions(+), 12 deletions(-) (limited to 'fs/ext2/balloc.c') diff --git a/fs/ext2/balloc.c b/fs/ext2/balloc.c index 1c3613998862..376aa77f3ca7 100644 --- 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 */ -- cgit