From: Ingo Molnar 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 Signed-off-by: Andrew Morton --- 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 2004-09-30 22:36:06.293914784 -0700 +++ 25-akpm/drivers/char/random.c 2004-09-30 22:36:06.298914024 -0700 @@ -2223,17 +2223,18 @@ 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)<