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From:   Greg Kroah-Hartman <gregkh@linuxfoundation.org>
To:     linux-kernel@vger.kernel.org
Cc:     Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
        stable@vger.kernel.org,
        Jan Henrik Weinstock <jan.weinstock@rwth-aachen.de>,
        Herbert Xu <herbert@gondor.apana.org.au>,
        Sasha Levin <sashal@kernel.org>
Subject: [PATCH 4.19 101/247] hwrng: timeriomem - Fix cooldown period calculation
Date:   Mon,  1 Mar 2021 17:12:01 +0100
Message-Id: <20210301161036.624360386@linuxfoundation.org>
In-Reply-To: <20210301161031.684018251@linuxfoundation.org>
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From: Jan Henrik Weinstock <jan.weinstock@rwth-aachen.de>

[ Upstream commit e145f5565dc48ccaf4cb50b7cfc48777bed8c100 ]

Ensure cooldown period tolerance of 1% is actually accounted for.

Fixes: ca3bff70ab32 ("hwrng: timeriomem - Improve performance...")
Signed-off-by: Jan Henrik Weinstock <jan.weinstock@rwth-aachen.de>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
 drivers/char/hw_random/timeriomem-rng.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/char/hw_random/timeriomem-rng.c b/drivers/char/hw_random/timeriomem-rng.c
index f615684028af7..ba01f24db6db0 100644
--- a/drivers/char/hw_random/timeriomem-rng.c
+++ b/drivers/char/hw_random/timeriomem-rng.c
@@ -72,7 +72,7 @@ static int timeriomem_rng_read(struct hwrng *hwrng, void *data,
 		 */
 		if (retval > 0)
 			usleep_range(period_us,
-					period_us + min(1, period_us / 100));
+					period_us + max(1, period_us / 100));
 
 		*(u32 *)data = readl(priv->io_base);
 		retval += sizeof(u32);
-- 
2.27.0