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| author | Sebastian Andrzej Siewior <bigeasy@linutronix.de> | 2017-06-30 16:37:13 +0200 |
|---|---|---|
| committer | Theodore Ts'o <tytso@mit.edu> | 2017-07-15 12:33:22 -0400 |
| commit | 72e5c740f6335e27253b8ff64d23d00337091535 (patch) | |
| tree | 277b0d7fdd627c80c54deafae9ab10b27c3d39de /drivers/char/random.c | |
| parent | eecabf567422eda02bd179f2707d8fe24f52d888 (diff) | |
| download | lwn-72e5c740f6335e27253b8ff64d23d00337091535.tar.gz lwn-72e5c740f6335e27253b8ff64d23d00337091535.zip | |
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 <Jason@zx2c4.com>
Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
Signed-off-by: Theodore Ts'o <tytso@mit.edu>
Diffstat (limited to 'drivers/char/random.c')
| -rw-r--r-- | drivers/char/random.c | 6 |
1 files 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); |