From: Matt Mackall <mpm@selenic.com>
Simplify output hash folding
Signed-off-by: Matt Mackall <mpm@selenic.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
---
25-akpm/drivers/char/random.c | 11 +++--------
1 files changed, 3 insertions(+), 8 deletions(-)
diff -puN drivers/char/random.c~random-pt3-simplify-hash-folding drivers/char/random.c
--- 25/drivers/char/random.c~random-pt3-simplify-hash-folding Wed Jan 19 15:30:01 2005
+++ 25-akpm/drivers/char/random.c Wed Jan 19 15:30:01 2005
@@ -1166,15 +1166,10 @@ static void extract_buf(struct entropy_s
* In case the hash function has some recognizable
* output pattern, we fold it in half.
*/
- for (i = 0; i < HASH_BUFFER_SIZE / 2; i++)
- buf[i] ^= buf[i + (HASH_BUFFER_SIZE + 1) / 2];
- if (HASH_BUFFER_SIZE & 1) {
- /* There's a middle word to deal with */
- x = buf[HASH_BUFFER_SIZE/2];
- x ^= (x >> 16); /* Fold it in half */
- ((__u16 *)buf)[HASH_BUFFER_SIZE - 1] = (__u16)x;
- }
+ buf[0] ^= buf[3];
+ buf[1] ^= buf[4];
+ buf[0] ^= rol32(buf[3], 16);
}
static ssize_t extract_entropy(struct entropy_store *r, void * buf,
_