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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
/*
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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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static void count_bits(register const char *bmPart, register int size,
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int *const tf)
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{
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char b;
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int tot = *tf;
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if (size > QNX4_BLOCK_SIZE) {
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size = QNX4_BLOCK_SIZE;
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}
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do {
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b = *bmPart++;
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tot += 8 - hweight8(b);
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size--;
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} while (size != 0);
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*tf = tot;
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}
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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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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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count_bits(bh->b_data, size - total, &total_free);
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brelse(bh);
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total += QNX4_BLOCK_SIZE;
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offset++;
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}
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return total_free;
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}
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