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random: initialize the non-blocking pool via add_hwgenerator_randomness()

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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 <tytso@mit.edu>
This commit is contained in:
Theodore Ts'o 2016-06-12 18:11:51 -04:00
parent 1a695a905c
commit 3371f3da08
1 changed files with 11 additions and 5 deletions
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16
drivers/char/random.c
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@ -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);
}