minixfs: kill manual hweight(), simplify
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
diff --git a/fs/minix/bitmap.c b/fs/minix/bitmap.c
index 7c82c29..ef175cb 100644
--- a/fs/minix/bitmap.c
+++ b/fs/minix/bitmap.c
@@ -16,39 +16,26 @@
#include <linux/bitops.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 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;
- struct buffer_head *bh;
- unsigned numblocks = minix_blocks_needed(numbits, blocksize);
-
- for (i=0; i<numblocks-1; i++) {
- if (!(bh=map[i]))
- return(0);
- for (j=0; j<bh->b_size; j++)
- sum += nibblemap[bh->b_data[j] & 0xf]
- + nibblemap[(bh->b_data[j]>>4) & 0xf];
+ __u32 sum = 0;
+ unsigned blocks = DIV_ROUND_UP(numbits, blocksize * 8);
+
+ while (blocks--) {
+ unsigned words = blocksize / 2;
+ __u16 *p = (__u16 *)(*map++)->b_data;
+ while (words--)
+ sum += 16 - hweight16(*p++);
}
- if (numblocks==0 || !(bh=map[numblocks-1]))
- 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);
+ return sum;
}
void minix_free_block(struct inode *inode, unsigned long block)
diff --git a/fs/minix/minix.h b/fs/minix/minix.h
index 6415fe0..26bbd55 100644
--- a/fs/minix/minix.h
+++ b/fs/minix/minix.h
@@ -130,7 +130,7 @@
if (!size)
return 0;
- size = (size >> 4) + ((size & 15) > 0);
+ size >>= 4;
while (*p++ == 0xffff) {
if (--size == 0)
return (p - addr) << 4;
