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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
/*
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* QNX4 file system, Linux implementation.
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*
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* Version : 0.2.1
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*
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* Using parts of the xiafs filesystem.
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*
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* History :
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*
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* 28-05-1998 by Richard Frowijn : first release.
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* 20-06-1998 by Frank Denis : basic optimisations.
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* 25-06-1998 by Frank Denis : qnx4_is_free, qnx4_set_bitmap, qnx4_bmap .
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* 28-06-1998 by Frank Denis : qnx4_free_inode (to be fixed) .
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*/
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#include <linux/buffer_head.h>
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#include <linux/bitops.h>
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#include "qnx4.h"
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unsigned long qnx4_count_free_blocks(struct super_block *sb)
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{
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int start = le32_to_cpu(qnx4_sb(sb)->BitMap->di_first_xtnt.xtnt_blk) - 1;
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int total = 0;
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int total_free = 0;
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int offset = 0;
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int size = le32_to_cpu(qnx4_sb(sb)->BitMap->di_size);
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struct buffer_head *bh;
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while (total < size) {
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int bytes = min(size - total, QNX4_BLOCK_SIZE);
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if ((bh = sb_bread(sb, start + offset)) == NULL) {
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printk(KERN_ERR "qnx4: I/O error in counting free blocks\n");
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break;
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}
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total_free += bytes * BITS_PER_BYTE -
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memweight(bh->b_data, bytes);
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brelse(bh);
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total += bytes;
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offset++;
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}
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return total_free;
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}
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