linux-kernel - [PATCH] iio: use div64_u64() instead of do

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Message-Id: <1644395873-3937-1-git-send-email-wangqing@vivo.com>
Date:   Wed,  9 Feb 2022 00:37:53 -0800
From:   Qing Wang <wangqing@...o.com>
To:     Jyoti Bhayana <jbhayana@...gle.com>,
        Jonathan Cameron <jic23@...nel.org>,
        Lars-Peter Clausen <lars@...afoo.de>,
        linux-iio@...r.kernel.org, linux-kernel@...r.kernel.org
Cc:     Wang Qing <wangqing@...o.com>
Subject: [PATCH] iio: use div64_u64() instead of do_div()

From: Wang Qing <wangqing@...o.com>

do_div() does a 64-by-32 division.
When the divisor is u64, do_div() truncates it to 32 bits, this means it
can test non-zero and be truncated to zero for division.

fix do_div.cocci warning:
do_div() does a 64-by-32 division, please consider using div64_u64 instead.

Signed-off-by: Wang Qing <wangqing@...o.com>
---
 drivers/iio/common/scmi_sensors/scmi_iio.c | 10 +++++-----
 1 file changed, 5 insertions(+), 5 deletions(-)

diff --git a/drivers/iio/common/scmi_sensors/scmi_iio.c b/drivers/iio/common/scmi_sensors/scmi_iio.c
index d538bf3..d6df5da
--- a/drivers/iio/common/scmi_sensors/scmi_iio.c
+++ b/drivers/iio/common/scmi_sensors/scmi_iio.c
@@ -160,7 +160,7 @@ static int scmi_iio_set_odr_val(struct iio_dev *iio_dev, int val, int val2)
 	mult = scnprintf(buf, sizeof(buf), "%llu", sf) - 1;
 
 	sec = int_pow(10, mult) * UHZ_PER_HZ;
-	do_div(sec, uHz);
+	div64_u64(sec, uHz);
 	if (sec == 0) {
 		dev_err(&iio_dev->dev,
 			"Trying to set invalid sensor update value for sensor %s",
@@ -237,10 +237,10 @@ static void convert_ns_to_freq(u64 interval_ns, u64 *hz, u64 *uhz)
 	u64 rem, freq;
 
 	freq = NSEC_PER_SEC;
-	rem = do_div(freq, interval_ns);
+	rem = div64_u64(freq, interval_ns);
 	*hz = freq;
 	*uhz = rem * 1000000UL;
-	do_div(*uhz, interval_ns);
+	div64_u64(*uhz, interval_ns);
 }
 
 static int scmi_iio_get_odr_val(struct iio_dev *iio_dev, int *val, int *val2)
@@ -266,7 +266,7 @@ static int scmi_iio_get_odr_val(struct iio_dev *iio_dev, int *val, int *val2)
 	mult = SCMI_SENS_CFG_GET_UPDATE_EXP(sensor_config);
 	if (mult < 0) {
 		sensor_interval_mult = int_pow(10, abs(mult));
-		do_div(sensor_update_interval, sensor_interval_mult);
+		div64_u64(sensor_update_interval, sensor_interval_mult);
 	} else {
 		sensor_interval_mult = int_pow(10, mult);
 		sensor_update_interval =
@@ -500,7 +500,7 @@ static u64 scmi_iio_convert_interval_to_ns(u32 val)
 	mult = SCMI_SENS_INTVL_GET_EXP(val);
 	if (mult < 0) {
 		sensor_interval_mult = int_pow(10, abs(mult));
-		do_div(sensor_update_interval, sensor_interval_mult);
+		div64_u64(sensor_update_interval, sensor_interval_mult);
 	} else {
 		sensor_interval_mult = int_pow(10, mult);
 		sensor_update_interval =
-- 
2.7.4