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authorTheodore Ts'o <tytso@mit.edu>2016-06-12 18:11:51 -0400
committerTheodore Ts'o <tytso@mit.edu>2016-06-13 11:15:17 -0400
commit3371f3da08cff4b75c1f2dce742d460539d6566d (patch)
treeb8a4a011ae96dfe7ad41a83367ffc153bd4ad768 /drivers/char/random.c
parent1a695a905c18548062509178b98bc91e67510864 (diff)
downloadleg-kernel-3371f3da08cff4b75c1f2dce742d460539d6566d.tar.gz
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 <tytso@mit.edu>
Diffstat (limited to 'drivers/char/random.c')
-rw-r--r--drivers/char/random.c16
1 files 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);
}