[RFC,11/41] random: convert add_timer_randomness() to queued_entropy API

Commit Message

Nicolai Stange Sept. 21, 2020, 7:58 a.m. UTC

In an effort to drop __credit_entropy_bits_fast() in favor of the new
__queue_entropy()/__dispatch_queued_entropy_fast() API, convert
add_timer_randomness() from the former to the latter.

There is no change in functionality at this point, because
__credit_entropy_bits_fast() has already been reimplemented on top of the
new API before.

Signed-off-by: Nicolai Stange <[e-mail]>
---
 drivers/char/random.c | 6 ++++--
 1 file changed, 4 insertions(+), 2 deletions(-)

Patch

diff --git a/drivers/char/random.c b/drivers/char/random.c
index b91d1fc08ac5..e8c86abde901 100644
--- a/drivers/char/random.c
+++ b/drivers/char/random.c
@@ -1400,6 +1400,7 @@  static void add_timer_randomness(struct timer_rand_state *state, unsigned num)
 	long delta, delta2, delta3;
 	bool reseed;
 	unsigned long flags;
+	struct queued_entropy q = { 0 };
 
 	sample.jiffies = jiffies;
 	sample.cycles = random_get_entropy();
@@ -1432,13 +1433,14 @@  static void add_timer_randomness(struct timer_rand_state *state, unsigned num)
 
 	r = &input_pool;
 	spin_lock_irqsave(&r->lock, flags);
-	__mix_pool_bytes(r, &sample, sizeof(sample));
 	/*
 	 * delta is now minimum absolute delta.
 	 * Round down by 1 bit on general principles,
 	 * and limit entropy estimate to 12 bits.
 	 */
-	reseed = __credit_entropy_bits_fast(r, min_t(int, fls(delta>>1), 11));
+	__queue_entropy(r, &q, min_t(int, fls(delta>>1), 11) << ENTROPY_SHIFT);
+	__mix_pool_bytes(r, &sample, sizeof(sample));
+	reseed = __dispatch_queued_entropy_fast(r, &q);
 	spin_unlock_irqrestore(&r->lock, flags);
 	if (reseed)
 		crng_reseed(&primary_crng, r);