868d64812a
Use hweight8 instead of counting for each bit Signed-off-by: Akinobu Mita <akinobu.mita@gmail.com> Acked-by: Anders Larsen <al@alarsen.net> Cc: Al Viro <viro@zeniv.linux.org.uk> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
58 lines
1.3 KiB
C
58 lines
1.3 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"
|
|
|
|
static void count_bits(register const char *bmPart, register int size,
|
|
int *const tf)
|
|
{
|
|
char b;
|
|
int tot = *tf;
|
|
|
|
if (size > QNX4_BLOCK_SIZE) {
|
|
size = QNX4_BLOCK_SIZE;
|
|
}
|
|
do {
|
|
b = *bmPart++;
|
|
tot += 8 - hweight8(b);
|
|
size--;
|
|
} while (size != 0);
|
|
*tf = tot;
|
|
}
|
|
|
|
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) {
|
|
if ((bh = sb_bread(sb, start + offset)) == NULL) {
|
|
printk(KERN_ERR "qnx4: I/O error in counting free blocks\n");
|
|
break;
|
|
}
|
|
count_bits(bh->b_data, size - total, &total_free);
|
|
brelse(bh);
|
|
total += QNX4_BLOCK_SIZE;
|
|
offset++;
|
|
}
|
|
|
|
return total_free;
|
|
}
|