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| author | Theodore Ts'o <tytso@mit.edu> | 2016-06-12 18:11:51 -0400 |
|---|---|---|
| committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2016-08-20 18:09:20 +0200 |
| commit | f41fc0bfede5bbeca4f09d75c76c4db5d6c0d2ee (patch) | |
| tree | 989c683e91c7282f439370ba6b6fc45c908a547a | |
| parent | adc58bfd4d75183a65f806b1b5354d1b65f832c6 (diff) | |
| download | lwn-f41fc0bfede5bbeca4f09d75c76c4db5d6c0d2ee.tar.gz lwn-f41fc0bfede5bbeca4f09d75c76c4db5d6c0d2ee.zip | |
random: initialize the non-blocking pool via add_hwgenerator_randomness()
commit 3371f3da08cff4b75c1f2dce742d460539d6566d upstream.
If we have a hardware RNG and are using the in-kernel rngd, we should
use this to initialize the non-blocking pool so that getrandom(2)
doesn't block unnecessarily.
Signed-off-by: Theodore Ts'o <tytso@mit.edu>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
| -rw-r--r-- | drivers/char/random.c | 16 |
1 files changed, 11 insertions, 5 deletions
diff --git a/drivers/char/random.c b/drivers/char/random.c index 0227b0465b40..802d0c840865 100644 --- a/drivers/char/random.c +++ b/drivers/char/random.c @@ -1847,12 +1847,18 @@ void add_hwgenerator_randomness(const char *buffer, size_t count, { struct entropy_store *poolp = &input_pool; - /* Suspend writing if we're above the trickle threshold. - * We'll be woken up again once below random_write_wakeup_thresh, - * or when the calling thread is about to terminate. - */ - wait_event_interruptible(random_write_wait, kthread_should_stop() || + if (unlikely(nonblocking_pool.initialized == 0)) + poolp = &nonblocking_pool; + else { + /* Suspend writing if we're above the trickle + * threshold. We'll be woken up again once below + * random_write_wakeup_thresh, or when the calling + * thread is about to terminate. + */ + wait_event_interruptible(random_write_wait, + kthread_should_stop() || ENTROPY_BITS(&input_pool) <= random_write_wakeup_bits); + } mix_pool_bytes(poolp, buffer, count); credit_entropy_bits(poolp, entropy); } |