[PATCH 6.8 469/715] crypto: qat - avoid division by zero

Sasha Levin
2024-03-24T22:42:41Z

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