[ 165/180] random: Adjust the number of loops when initializing

From: Willy Tarreau
Date: Mon Oct 01 2012 - 20:10:15 EST


2.6.32-longterm review patch. If anyone has any objections, please let me know.

------------------

From: H. Peter Anvin <hpa@xxxxxxxxxxxxxxx>

commit 2dac8e54f988ab58525505d7ef982493374433c3 upstream.

When we are initializing using arch_get_random_long() we only need to
loop enough times to touch all the bytes in the buffer; using
poolwords for that does twice the number of operations necessary on a
64-bit machine, since in the random number generator code "word" means
32 bits.

Signed-off-by: H. Peter Anvin <hpa@xxxxxxxxxxxxxxx>
Cc: "Theodore Ts'o" <tytso@xxxxxxx>
Link: http://lkml.kernel.org/r/1324589281-31931-1-git-send-email-tytso@xxxxxxx
Signed-off-by: Paul Gortmaker <paul.gortmaker@xxxxxxxxxxxxx>
Signed-off-by: Willy Tarreau <w@xxxxxx>
---
drivers/char/random.c | 2 +-
1 files changed, 1 insertions(+), 1 deletions(-)

diff --git a/drivers/char/random.c b/drivers/char/random.c
index d67890f..5e106b1 100644
--- a/drivers/char/random.c
+++ b/drivers/char/random.c
@@ -975,7 +975,7 @@ static void init_std_data(struct entropy_store *r)

now = ktime_get_real();
mix_pool_bytes(r, &now, sizeof(now));
- for (i = r->poolinfo->poolwords; i; i--) {
+ for (i = r->poolinfo->POOLBYTES; i > 0; i -= sizeof flags) {
if (!arch_get_random_long(&flags))
break;
mix_pool_bytes(r, &flags, sizeof(flags));
--
1.7.2.1.45.g54fbc



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