Re: [PATCH v3 03/13] random: invalidate batched entropy after crng init

Commit Message

Jason A. Donenfeld June 7, 2017, 6:16 p.m. UTC

Strange, not all compilers do this warning. Fixing with:

#if BITS_PER_LONG == 64
@@ -2099,8 +2099,8 @@ static DEFINE_PER_CPU(struct batched_entropy,
batched_entropy_u32);
u32 get_random_u32(void)
{
       u32 ret;
-       bool use_lock = crng_init < 2;
-       unsigned long flags;
+       const bool use_lock = READ_ONCE(crng_init) < 2;
+       unsigned long flags = 0;
       struct batched_entropy *batch;

       if (arch_get_random_int(&ret))

Const, because it's more correct. READ_ONCE to be certain that the
compiler doesn't try to paste the expression into both uses. And
finally flags=0 to shutup the compiler.

If anybody has a better way of approaching this, feel free to chime in.

Patch

diff --git a/drivers/char/random.c b/drivers/char/random.c
index 12758db..5252690 100644
--- a/drivers/char/random.c
+++ b/drivers/char/random.c
@@ -2061,8 +2061,8 @@  static DEFINE_PER_CPU(struct batched_entropy,
batched_entropy_u64);
u64 get_random_u64(void)
{
       u64 ret;
-       bool use_lock = crng_init < 2;
-       unsigned long flags;
+       const bool use_lock = READ_ONCE(crng_init) < 2;
+       unsigned long flags = 0;
       struct batched_entropy *batch;