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authorMatt Mackall <mpm@selenic.com>2008-04-29 01:03:02 -0700
committerLinus Torvalds <torvalds@linux-foundation.org>2008-04-29 08:06:25 -0700
commitfeee76972bcc54b2b1d1dc28bc6c16a8daa9aff8 (patch)
treedb031968e6a4f76b060298d5d0b3499566ad944d /drivers/char
parent433582093a9dc5454ba03b4a7ea201d85e6aa4de (diff)
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')
-rw-r--r--drivers/char/random.c22
1 files changed, 10 insertions, 12 deletions
diff --git a/drivers/char/random.c b/drivers/char/random.c
index 973706e97e7..3823cb2e3b9 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;