mirror of
https://github.com/torvalds/linux.git
synced 2024-11-27 14:41:39 +00:00
9b58f6d4aa
Use memweight() to count the total number of bits clear in memory area. 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. Signed-off-by: Akinobu Mita <akinobu.mita@gmail.com> Acked-by: Anders Larsen <al@alarsen.net> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
45 lines
1.0 KiB
C
45 lines
1.0 KiB
C
/*
|
|
* QNX4 file system, Linux implementation.
|
|
*
|
|
* Version : 0.2.1
|
|
*
|
|
* Using parts of the xiafs filesystem.
|
|
*
|
|
* History :
|
|
*
|
|
* 28-05-1998 by Richard Frowijn : first release.
|
|
* 20-06-1998 by Frank Denis : basic optimisations.
|
|
* 25-06-1998 by Frank Denis : qnx4_is_free, qnx4_set_bitmap, qnx4_bmap .
|
|
* 28-06-1998 by Frank Denis : qnx4_free_inode (to be fixed) .
|
|
*/
|
|
|
|
#include <linux/buffer_head.h>
|
|
#include <linux/bitops.h>
|
|
#include "qnx4.h"
|
|
|
|
unsigned long qnx4_count_free_blocks(struct super_block *sb)
|
|
{
|
|
int start = le32_to_cpu(qnx4_sb(sb)->BitMap->di_first_xtnt.xtnt_blk) - 1;
|
|
int total = 0;
|
|
int total_free = 0;
|
|
int offset = 0;
|
|
int size = le32_to_cpu(qnx4_sb(sb)->BitMap->di_size);
|
|
struct buffer_head *bh;
|
|
|
|
while (total < size) {
|
|
int bytes = min(size - total, QNX4_BLOCK_SIZE);
|
|
|
|
if ((bh = sb_bread(sb, start + offset)) == NULL) {
|
|
printk(KERN_ERR "qnx4: I/O error in counting free blocks\n");
|
|
break;
|
|
}
|
|
total_free += bytes * BITS_PER_BYTE -
|
|
memweight(bh->b_data, bytes);
|
|
brelse(bh);
|
|
total += bytes;
|
|
offset++;
|
|
}
|
|
|
|
return total_free;
|
|
}
|