From: Ingo Molnar <mingo@elte.hu>
The attached patch fixes possibly long scheduling latencies in the
/dev/random driver's rekey_seq_generator() function, by moving the
expensive get_random_bytes() function out from under ip_lock.
Has been in the -VP patchset for quite some time.
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Signed-off-by: Andrew Morton <akpm@osdl.org>
---
25-akpm/drivers/char/random.c | 5 +++--
1 files changed, 3 insertions(+), 2 deletions(-)
diff -puN drivers/char/random.c~sched-fix-latency-in-random-driver drivers/char/random.c
--- 25/drivers/char/random.c~sched-fix-latency-in-random-driver Tue Sep 14 17:38:28 2004
+++ 25-akpm/drivers/char/random.c Tue Sep 14 17:38:28 2004
@@ -2220,17 +2220,18 @@ static unsigned int ip_cnt;
static void rekey_seq_generator(void *private_)
{
- struct keydata *keyptr;
+ struct keydata *keyptr, tmp;
struct timeval tv;
do_gettimeofday(&tv);
+ get_random_bytes(tmp.secret, sizeof(tmp.secret));
spin_lock_bh(&ip_lock);
keyptr = &ip_keydata[ip_cnt&1];
keyptr = &ip_keydata[1^(ip_cnt&1)];
keyptr->rekey_time = tv.tv_sec;
- get_random_bytes(keyptr->secret, sizeof(keyptr->secret));
+ memcpy(keyptr->secret, tmp.secret, sizeof(keyptr->secret));
keyptr->count = (ip_cnt&COUNT_MASK)<<HASH_BITS;
mb();
ip_cnt++;
_