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From:   "Jason A. Donenfeld" <Jason@zx2c4.com>
To:     herbert@gondor.apana.org.au, linux-crypto@vger.kernel.org
Cc:     "Jason A. Donenfeld" <Jason@zx2c4.com>
Subject: [PATCH] hw_random: use add_hwgenerator_randomness() for early entropy
Date:   Sat,  5 Nov 2022 21:44:17 +0100
Message-Id: <20221105204417.137001-1-Jason@zx2c4.com>
MIME-Version: 1.0
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Precedence: bulk

Rather than calling add_device_randomness(), the add_early_randomness()
function should use add_hwgenerator_randomness(), so that the early
entropy can be potentially credited, which allows for the RNG to
initialize earlier without having to wait for the kthread to come up.

Cc: Herbert Xu <herbert@gondor.apana.org.au>
Signed-off-by: Jason A. Donenfeld <Jason@zx2c4.com>
---
 drivers/char/hw_random/core.c | 6 ++++--
 1 file changed, 4 insertions(+), 2 deletions(-)

diff --git a/drivers/char/hw_random/core.c b/drivers/char/hw_random/core.c
index cc002b0c2f0c..8c0819ce2781 100644
--- a/drivers/char/hw_random/core.c
+++ b/drivers/char/hw_random/core.c
@@ -69,8 +69,10 @@ static void add_early_randomness(struct hwrng *rng)
 	mutex_lock(&reading_mutex);
 	bytes_read = rng_get_data(rng, rng_fillbuf, 32, 0);
 	mutex_unlock(&reading_mutex);
-	if (bytes_read > 0)
-		add_device_randomness(rng_fillbuf, bytes_read);
+	if (bytes_read > 0) {
+		size_t entropy = bytes_read * 8 * rng->quality / 1024;
+		add_hwgenerator_randomness(rng_fillbuf, bytes_read, entropy);
+	}
 }
 
 static inline void cleanup_rng(struct kref *kref)
-- 
2.38.1