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From:   Nicolai Stange <nstange@suse.de>
To:     "Theodore Y. Ts'o" <tytso@mit.edu>
Cc:     linux-crypto@vger.kernel.org, LKML <linux-kernel@vger.kernel.org>,
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        Dan Carpenter <dan.carpenter@oracle.com>,
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        Eric Biggers <ebiggers@kernel.org>,
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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 15/41] random: convert add_hwgenerator_randomness() to queued_entropy API
Date:   Mon, 21 Sep 2020 09:58:31 +0200
Message-Id: <20200921075857.4424-16-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() in favor of the new
queue_entropy()/dispatch_queued_entropy() API, convert
add_hwgenerator_randomness() from the former to the latter.

As a side effect, the pool entropy watermark as tracked over the duration
of the mix_pool_bytes() operation is now taken correctly taken into account
when calulating the amount of new entropy to dispatch to the pool based on
the latter's fill level.

Signed-off-by: Nicolai Stange <nstange@suse.de>
---
 drivers/char/random.c | 4 +++-
 1 file changed, 3 insertions(+), 1 deletion(-)

diff --git a/drivers/char/random.c b/drivers/char/random.c
index 60ce185d7b2d..78e65367ea86 100644
--- a/drivers/char/random.c
+++ b/drivers/char/random.c
@@ -2640,6 +2640,7 @@ void add_hwgenerator_randomness(const char *buffer, size_t count,
 				size_t entropy)
 {
 	struct entropy_store *poolp = &input_pool;
+	struct queued_entropy q = { 0 };
 
 	if (unlikely(crng_init == 0)) {
 		crng_fast_load(buffer, count);
@@ -2652,8 +2653,9 @@ void add_hwgenerator_randomness(const char *buffer, size_t count,
 	 */
 	wait_event_interruptible(random_write_wait, kthread_should_stop() ||
 			ENTROPY_BITS(&input_pool) <= random_write_wakeup_bits);
+	queue_entropy(poolp, &q, entropy << ENTROPY_SHIFT);
 	mix_pool_bytes(poolp, buffer, count);
-	credit_entropy_bits(poolp, entropy);
+	dispatch_queued_entropy(poolp, &q);
 }
 EXPORT_SYMBOL_GPL(add_hwgenerator_randomness);
 
-- 
2.26.2