From 897ece56e714a2cc64e6914cb89a362d7021b36e Mon Sep 17 00:00:00 2001 From: Daniel Borkmann Date: Thu, 8 Oct 2015 01:20:38 +0200 Subject: [PATCH] random32: add prandom_init_once helper for own rngs Add a prandom_init_once() facility that works on the rnd_state, so that users that are keeping their own state independent from prandom_u32() can initialize their taus113 per cpu states. The motivation here is similar to net_get_random_once(): initialize the state as late as possible in the hope that enough entropy has been collected for the seeding. prandom_init_once() makes use of the recently introduced prandom_seed_full_state() helper and is generic enough so that it could also be used on fast-paths due to the DO_ONCE(). Signed-off-by: Daniel Borkmann Acked-by: Hannes Frederic Sowa Acked-by: Alexei Starovoitov Signed-off-by: David S. Miller --- include/linux/random.h | 6 ++++++ lib/random32.c | 2 +- 2 files changed, 7 insertions(+), 1 deletion(-) diff --git a/include/linux/random.h b/include/linux/random.h index e651874df2c9..a75840c1aa71 100644 --- a/include/linux/random.h +++ b/include/linux/random.h @@ -7,6 +7,8 @@ #define _LINUX_RANDOM_H #include +#include + #include struct random_ready_callback { @@ -45,6 +47,10 @@ struct rnd_state { u32 prandom_u32_state(struct rnd_state *state); void prandom_bytes_state(struct rnd_state *state, void *buf, size_t nbytes); +void prandom_seed_full_state(struct rnd_state __percpu *pcpu_state); + +#define prandom_init_once(pcpu_state) \ + DO_ONCE(prandom_seed_full_state, (pcpu_state)) /** * prandom_u32_max - returns a pseudo-random number in interval [0, ep_ro) diff --git a/lib/random32.c b/lib/random32.c index 36c09fb3fec9..12111910ccd0 100644 --- a/lib/random32.c +++ b/lib/random32.c @@ -238,7 +238,7 @@ static void __init __prandom_start_seed_timer(void) add_timer(&seed_timer); } -static void prandom_seed_full_state(struct rnd_state __percpu *pcpu_state) +void prandom_seed_full_state(struct rnd_state __percpu *pcpu_state) { int i; -- 2.20.1