From 3371f3da08cff4b75c1f2dce742d460539d6566d Mon Sep 17 00:00:00 2001 From: Theodore Ts'o Date: Sun, 12 Jun 2016 18:11:51 -0400 Subject: [PATCH] random: initialize the non-blocking pool via add_hwgenerator_randomness() 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. Cc: stable@kernel.org Signed-off-by: Theodore Ts'o --- drivers/char/random.c | 16 +++++++++++----- 1 file changed, 11 insertions(+), 5 deletions(-) diff --git a/drivers/char/random.c b/drivers/char/random.c index 0158d3bff7e5..4e2627a8d226 100644 --- a/drivers/char/random.c +++ b/drivers/char/random.c @@ -1849,12 +1849,18 @@ 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); } -- 2.39.5