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>
diff --git a/drivers/char/random.c b/drivers/char/random.c
index 973706e..3823cb2 100644
--- a/drivers/char/random.c
+++ b/drivers/char/random.c
@@ -455,7 +455,7 @@
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 @@
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 @@
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;
