Commit 3371f3da authored by Theodore Ts'o's avatar Theodore Ts'o
Browse files

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: default avatarTheodore Ts'o <tytso@mit.edu>
parent 1a695a90

drivers/char/random.c

+11 −5
Original line number Diff line number Diff line
@@ -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.

	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() ||

		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);

}