Messages in this thread Patch in this message | | | Date | Sun, 13 Feb 2022 19:54:01 +0100 | Subject | Re: [PATCH] iio: use div64_u64() instead of do_div() | From | Christophe JAILLET <> |
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Le 13/02/2022 à 19:50, Christophe JAILLET a écrit : > Le 13/02/2022 à 18:59, Jonathan Cameron a écrit : >> On Wed, 9 Feb 2022 00:37:53 -0800 >> Qing Wang <wangqing-DGpbCiVdSXo@public.gmane.org> wrote: >> >>> From: Wang Qing <wangqing-DGpbCiVdSXo@public.gmane.org> >>> >>> 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-DGpbCiVdSXo@public.gmane.org> >> 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-bIcnvbaLZ9MEGnE8C9+IrQ@public.gmane.org/
Broken link, sorry:
[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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