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minixfs: kill manual hweight(), simplify

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Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
This commit is contained in:
Al Viro 2011-08-26 22:38:50 -04:00
parent 016e8d44bc
commit f1fd306a91
2 changed files with 16 additions and 29 deletions
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43
fs/minix/bitmap.c
View file

@ -16,39 +16,26 @@
#include <linux/bitops.h> #include <linux/bitops.h>
#include <linux/sched.h> #include <linux/sched.h>
static const int nibblemap[] = { 4,3,3,2,3,2,2,1,3,2,2,1,2,1,1,0 };
static DEFINE_SPINLOCK(bitmap_lock); static DEFINE_SPINLOCK(bitmap_lock);
static unsigned long count_free(struct buffer_head *map[], unsigned blocksize, __u32 numbits) /*
* bitmap consists of blocks filled with 16bit words
* bit set == busy, bit clear == free
* endianness is a mess, but for counting zero bits it really doesn't matter...
*/
static __u32 count_free(struct buffer_head *map[], unsigned blocksize, __u32 numbits)
{ {
unsigned i, j, sum = 0; __u32 sum = 0;
struct buffer_head *bh; unsigned blocks = DIV_ROUND_UP(numbits, blocksize * 8);
unsigned numblocks = minix_blocks_needed(numbits, blocksize);
while (blocks--) {
for (i=0; i<numblocks-1; i++) { unsigned words = blocksize / 2;
if (!(bh=map[i])) __u16 *p = (__u16 *)(*map++)->b_data;
return(0); while (words--)
for (j=0; j<bh->b_size; j++) sum += 16 - hweight16(*p++);
sum += nibblemap[bh->b_data[j] & 0xf]
+ nibblemap[(bh->b_data[j]>>4) & 0xf];
} }
if (numblocks==0 || !(bh=map[numblocks-1])) return sum;
return(0);
i = ((numbits - (numblocks-1) * bh->b_size * 8) / 16) * 2;
for (j=0; j<i; j++) {
sum += nibblemap[bh->b_data[j] & 0xf]
+ nibblemap[(bh->b_data[j]>>4) & 0xf];
}
i = numbits%16;
if (i!=0) {
i = *(__u16 *)(&bh->b_data[j]) | ~((1<<i) - 1);
sum += nibblemap[i & 0xf] + nibblemap[(i>>4) & 0xf];
sum += nibblemap[(i>>8) & 0xf] + nibblemap[(i>>12) & 0xf];
}
return(sum);
} }
void minix_free_block(struct inode *inode, unsigned long block) void minix_free_block(struct inode *inode, unsigned long block)

2
fs/minix/minix.h
View file

@ -130,7 +130,7 @@ static inline int minix_find_first_zero_bit(const void *vaddr, unsigned size)
if (!size) if (!size)
return 0; return 0;
size = (size >> 4) + ((size & 15) > 0); size >>= 4;
while (*p++ == 0xffff) { while (*p++ == 0xffff) {
if (--size == 0) if (--size == 0)
return (p - addr) << 4; return (p - addr) << 4;