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| author | Daniel Borkmann <daniel@iogearbox.net> | 2015-10-08 01:20:38 +0200 |
|---|---|---|
| committer | David S. Miller <davem@davemloft.net> | 2015-10-08 05:26:38 -0700 |
| commit | 897ece56e714a2cc64e6914cb89a362d7021b36e (patch) | |
| tree | c965cddb6a87f0bc6d96cceaa36efe42af8158da | |
| parent | 0dd50d1b0c003ab4f17597fe1198bb57a2fadc06 (diff) | |
| download | linux-exynos-897ece56e714a2cc64e6914cb89a362d7021b36e.tar.gz linux-exynos-897ece56e714a2cc64e6914cb89a362d7021b36e.tar.bz2 linux-exynos-897ece56e714a2cc64e6914cb89a362d7021b36e.zip | |
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 <daniel@iogearbox.net>
Acked-by: Hannes Frederic Sowa <hannes@stressinduktion.org>
Acked-by: Alexei Starovoitov <ast@kernel.org>
Signed-off-by: David S. Miller <davem@davemloft.net>
| -rw-r--r-- | include/linux/random.h | 6 | ||||
| -rw-r--r-- | lib/random32.c | 2 |
2 files changed, 7 insertions, 1 deletions
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 <linux/list.h> +#include <linux/once.h> + #include <uapi/linux/random.h> 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; |