Since commit 4a072c71f49b ("random: silence compiler warnings and fix
race") there is a READ_ONCE().
I doubt that this required here but I don't have the time to argue with
Jason. Instead I push the access further down so we don't read crng_init
if we can leave the function after arch_get_random_XXX(). This is
something the compiler did before the READ_ONCE() got it.Cc: Jason A. Donenfeld <[email protected]> Signed-off-by: Sebastian Andrzej Siewior <[email protected]> --- 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 01a260f67437..5e3765f6a61d 100644 --- a/drivers/char/random.c +++ b/drivers/char/random.c @@ -2041,7 +2041,7 @@ 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; @@ -2053,6 +2053,7 @@ u64 get_random_u64(void) arch_get_random_long((unsigned long *)&ret + 1)) return ret; #endif + use_lock = READ_ONCE(crng_init) < 2; batch = &get_cpu_var(batched_entropy_u64); if (use_lock) @@ -2073,13 +2074,14 @@ 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; if (arch_get_random_int(&ret)) return ret; + 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); -- 2.13.2
