Messages in this thread Patch in this message | | | Date | Sun, 13 Feb 2022 19:50:55 +0100 | Subject | Re: [PATCH] iio: use div64_u64() instead of do_div() | From | Christophe JAILLET <> |
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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 = > >
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