The add_ptr variable wasn't used in a sensible way, use only i instead.
i got reused later for a different purpose, use j instead.
While we're here, put tap0 first in the tap list and add a comment.
Signed-off-by: Matt Mackall <[EMAIL PROTECTED]>
diff -r bc31fa097d34 -r 8f286e22c84d drivers/char/random.c
--- a/drivers/char/random.c Thu Jan 17 20:25:23 2008 -0600
+++ b/drivers/char/random.c Thu Jan 17 20:25:23 2008 -0600
@@ -454,7 +454,7 @@
static __u32 const twist_table[8] = {
0x00000000, 0x3b6e20c8, 0x76dc4190, 0x4db26158,
0xedb88320, 0xd6d6a3e8, 0x9b64c2b0, 0xa00ae278 };
- unsigned long i, add_ptr, tap1, tap2, tap3, tap4, tap5;
+ unsigned long i, j, tap1, tap2, tap3, tap4, tap5;
int input_rotate;
int wordmask = r->poolinfo->poolwords - 1;
__u32 w;
@@ -469,19 +469,21 @@
spin_lock_irqsave(&r->lock, flags);
input_rotate = r->input_rotate;
- add_ptr = r->add_ptr;
+ i = r->add_ptr;
while (nwords--) {
w = rol32(*in++, input_rotate & 31);
- i = add_ptr = (add_ptr - 1) & wordmask;
+ i = (i - 1) & wordmask;
/* XOR in the various taps */
+ w ^= r->pool[i];
w ^= r->pool[(i + tap1) & wordmask];
w ^= r->pool[(i + tap2) & wordmask];
w ^= r->pool[(i + tap3) & wordmask];
w ^= r->pool[(i + tap4) & wordmask];
w ^= r->pool[(i + tap5) & wordmask];
- w ^= r->pool[i];
+
+ /* Mix the result back in with a twist */
r->pool[i] = (w >> 3) ^ twist_table[w & 7];
/*
@@ -494,14 +496,11 @@
}
r->input_rotate = input_rotate;
- r->add_ptr = add_ptr;
+ r->add_ptr = i;
- if (out) {
- for (i = 0; i < 16; i++) {
- out[i] = r->pool[add_ptr];
- add_ptr = (add_ptr - 1) & wordmask;
- }
- }
+ if (out)
+ for (j = 0; j < 16; j++)
+ out[j] = r->pool[(i - j) & wordmask];
spin_unlock_irqrestore(&r->lock, flags);
}
--
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