lkml.org 
[lkml]   [2022]   [Feb]   [13]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
Patch in this message
/
Date
SubjectRe: [PATCH] iio: use div64_u64() instead of do_div()
From
Le 13/02/2022 à 18:59, Jonathan Cameron a écrit :
> On Wed, 9 Feb 2022 00:37:53 -0800
> Qing Wang <wangqing@vivo.com> wrote:
>
>> From: Wang Qing <wangqing@vivo.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@vivo.com>
> These look correct to me. Jyoti, please could give these a sanity check?
>

This is wrong.

See [1].

CJ

[1]:
https://lore.kernel.org/linux-kernel/20211117112559.jix3hmx7uwqmuryg@pengutronix.de/

> Thanks,
>
> Jonathan
>
>> ---
>> 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 =
>
>

\
 
 \ /
  Last update: 2022-02-13 19:52    [W:0.051 / U:1.640 seconds]
©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site