random: remove some prefetch logic
The urandom output pool (ie the fast path) fits in one cacheline, so
this is pretty unnecessary. Further, the output path has already
fetched the entire pool to hash it before calling in here.
(This was the only user of prefetch_range in the kernel, and it passed
in words rather than bytes!)
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 3823cb2..a754132 100644
--- a/drivers/char/random.c
+++ b/drivers/char/random.c
@@ -457,7 +457,7 @@
unsigned long i, add_ptr, tap1, tap2, tap3, tap4, tap5;
int input_rotate;
int wordmask = r->poolinfo->poolwords - 1;
- __u32 w, next_w;
+ __u32 w;
unsigned long flags;
/* Taps are constant, so we can load them without holding r->lock. */
@@ -466,17 +466,13 @@
tap3 = r->poolinfo->tap3;
tap4 = r->poolinfo->tap4;
tap5 = r->poolinfo->tap5;
- next_w = *in++;
spin_lock_irqsave(&r->lock, flags);
- prefetch_range(r->pool, wordmask);
input_rotate = r->input_rotate;
add_ptr = r->add_ptr;
while (nwords--) {
- w = rol32(next_w, input_rotate & 31);
- if (nwords > 0)
- next_w = *in++;
+ w = rol32(*in++, input_rotate & 31);
i = add_ptr = (add_ptr - 1) & wordmask;
/* XOR in the various taps */