diff options
| author | Matt Mackall <mpm@selenic.com> | 2008-04-29 10:03:02 +0200 |
|---|---|---|
| committer | Linus Torvalds <torvalds@linux-foundation.org> | 2008-04-29 17:06:25 +0200 |
| commit | feee76972bcc54b2b1d1dc28bc6c16a8daa9aff8 (patch) | |
| tree | db031968e6a4f76b060298d5d0b3499566ad944d /drivers/char/random.c | |
| parent | random: remove cacheline alignment for locks (diff) | |
| download | linux-feee76972bcc54b2b1d1dc28bc6c16a8daa9aff8.tar.xz linux-feee76972bcc54b2b1d1dc28bc6c16a8daa9aff8.zip | |
random: eliminate redundant new_rotate variable
- eliminate new_rotate
- move input_rotate masking
- simplify input_rotate update
- move input_rotate update to end of inner loop for readability
Signed-off-by: Matt Mackall <mpm@selenic.com>
Cc: Theodore Ts'o <tytso@mit.edu>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Diffstat (limited to 'drivers/char/random.c')
| -rw-r--r-- | drivers/char/random.c | 22 |
1 files changed, 10 insertions, 12 deletions
diff --git a/drivers/char/random.c b/drivers/char/random.c index 973706e97e77..3823cb2e3b9a 100644 --- a/drivers/char/random.c +++ b/drivers/char/random.c @@ -455,7 +455,7 @@ static void __add_entropy_words(struct entropy_store *r, const __u32 *in, 0x00000000, 0x3b6e20c8, 0x76dc4190, 0x4db26158, 0xedb88320, 0xd6d6a3e8, 0x9b64c2b0, 0xa00ae278 }; unsigned long i, add_ptr, tap1, tap2, tap3, tap4, tap5; - int new_rotate, input_rotate; + int input_rotate; int wordmask = r->poolinfo->poolwords - 1; __u32 w, next_w; unsigned long flags; @@ -474,20 +474,10 @@ static void __add_entropy_words(struct entropy_store *r, const __u32 *in, add_ptr = r->add_ptr; while (nwords--) { - w = rol32(next_w, input_rotate); + w = rol32(next_w, input_rotate & 31); if (nwords > 0) next_w = *in++; i = add_ptr = (add_ptr - 1) & wordmask; - /* - * Normally, we add 7 bits of rotation to the pool. - * At the beginning of the pool, add an extra 7 bits - * rotation, so that successive passes spread the - * input bits across the pool evenly. - */ - new_rotate = input_rotate + 14; - if (i) - new_rotate = input_rotate + 7; - input_rotate = new_rotate & 31; /* XOR in the various taps */ w ^= r->pool[(i + tap1) & wordmask]; @@ -497,6 +487,14 @@ static void __add_entropy_words(struct entropy_store *r, const __u32 *in, w ^= r->pool[(i + tap5) & wordmask]; w ^= r->pool[i]; r->pool[i] = (w >> 3) ^ twist_table[w & 7]; + + /* + * Normally, we add 7 bits of rotation to the pool. + * At the beginning of the pool, add an extra 7 bits + * rotation, so that successive passes spread the + * input bits across the pool evenly. + */ + input_rotate += i ? 7 : 14; } r->input_rotate = input_rotate; |