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From:   Nicolai Stange <nstange@suse.de>
To:     "Theodore Y. Ts'o" <tytso@mit.edu>
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        =?UTF-8?q?Stephan=20M=C3=BCller?= <smueller@chronox.de>,
        Torsten Duwe <duwe@suse.de>, Petr Tesarik <ptesarik@suse.cz>,
        Nicolai Stange <nstange@suse.de>
Subject: [RFC PATCH 11/41] random: convert add_timer_randomness() to queued_entropy API
Date:   Mon, 21 Sep 2020 09:58:27 +0200
Message-Id: <20200921075857.4424-12-nstange@suse.de>
In-Reply-To: <20200921075857.4424-1-nstange@suse.de>
References: <20200921075857.4424-1-nstange@suse.de>
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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 <nstange@suse.de>
---
 drivers/char/random.c | 6 ++++--
 1 file changed, 4 insertions(+), 2 deletions(-)

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);
-- 
2.26.2