From 72e5c740f6335e27253b8ff64d23d00337091535 Mon Sep 17 00:00:00 2001 From: Sebastian Andrzej Siewior Date: Fri, 30 Jun 2017 16:37:13 +0200 Subject: [PATCH] random: reorder READ_ONCE() in get_random_uXX Avoid the READ_ONCE in commit 4a072c71f49b ("random: silence compiler warnings and fix race") if we can leave the function after arch_get_random_XXX(). Cc: Jason A. Donenfeld Signed-off-by: Sebastian Andrzej Siewior Signed-off-by: Theodore Ts'o --- drivers/char/random.c | 6 ++++-- 1 file changed, 4 insertions(+), 2 deletions(-) diff --git a/drivers/char/random.c b/drivers/char/random.c index 799d37981d99..05d255e1c112 100644 --- a/drivers/char/random.c +++ b/drivers/char/random.c @@ -2089,7 +2089,7 @@ static DEFINE_PER_CPU(struct batched_entropy, batched_entropy_u64); u64 get_random_u64(void) { u64 ret; - bool use_lock = READ_ONCE(crng_init) < 2; + bool use_lock; unsigned long flags = 0; struct batched_entropy *batch; static void *previous; @@ -2105,6 +2105,7 @@ u64 get_random_u64(void) warn_unseeded_randomness(&previous); + use_lock = READ_ONCE(crng_init) < 2; batch = &get_cpu_var(batched_entropy_u64); if (use_lock) read_lock_irqsave(&batched_entropy_reset_lock, flags); @@ -2124,7 +2125,7 @@ static DEFINE_PER_CPU(struct batched_entropy, batched_entropy_u32); u32 get_random_u32(void) { u32 ret; - bool use_lock = READ_ONCE(crng_init) < 2; + bool use_lock; unsigned long flags = 0; struct batched_entropy *batch; static void *previous; @@ -2134,6 +2135,7 @@ u32 get_random_u32(void) warn_unseeded_randomness(&previous); + use_lock = READ_ONCE(crng_init) < 2; batch = &get_cpu_var(batched_entropy_u32); if (use_lock) read_lock_irqsave(&batched_entropy_reset_lock, flags); -- 2.30.2