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From: Sasha Levin <sashal@kernel.org>
To: linux-kernel@vger.kernel.org,
	stable@vger.kernel.org
Cc: Adam Guerin <adam.guerin@intel.com>,
	Giovanni Cabiddu <giovanni.cabiddu@intel.com>,
	Herbert Xu <herbert@gondor.apana.org.au>,
	Sasha Levin <sashal@kernel.org>
Subject: [PATCH 6.8 469/715] crypto: qat - avoid division by zero
Date: Sun, 24 Mar 2024 18:30:48 -0400
Message-ID: <20240324223455.1342824-470-sashal@kernel.org>
In-Reply-To: <20240324223455.1342824-1-sashal@kernel.org>
References: <20240324223455.1342824-1-sashal@kernel.org>
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From: Adam Guerin <adam.guerin@intel.com>

[ Upstream commit f99fb7d660f7c818105803f1f1915396a14d18ad ]

Check if delta_us is not zero and return -EINVAL if it is.
delta_us is unlikely to be zero as there is a sleep between the reads of
the two timestamps.

This is to fix the following warning when compiling the QAT driver
using clang scan-build:
    drivers/crypto/intel/qat/qat_common/adf_clock.c:87:9: warning: Division by zero [core.DivideZero]
       87 |         temp = DIV_ROUND_CLOSEST_ULL(temp, delta_us);
          |                ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

Fixes: e2980ba57e79 ("crypto: qat - add measure clock frequency")
Signed-off-by: Adam Guerin <adam.guerin@intel.com>
Reviewed-by: Giovanni Cabiddu <giovanni.cabiddu@intel.com>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
 drivers/crypto/intel/qat/qat_common/adf_clock.c | 3 +++
 1 file changed, 3 insertions(+)

diff --git a/drivers/crypto/intel/qat/qat_common/adf_clock.c b/drivers/crypto/intel/qat/qat_common/adf_clock.c
index 01e0a389e462b..cf89f57de2a70 100644
--- a/drivers/crypto/intel/qat/qat_common/adf_clock.c
+++ b/drivers/crypto/intel/qat/qat_common/adf_clock.c
@@ -83,6 +83,9 @@ static int measure_clock(struct adf_accel_dev *accel_dev, u32 *frequency)
 	}
 
 	delta_us = timespec_to_us(&ts3) - timespec_to_us(&ts1);
+	if (!delta_us)
+		return -EINVAL;
+
 	temp = (timestamp2 - timestamp1) * ME_CLK_DIVIDER * 10;
 	temp = DIV_ROUND_CLOSEST_ULL(temp, delta_us);
 	/*
-- 
2.43.0