Re: [PATCH 00/28] iio: zero init stack with { } instead of memset()

[Jonathan Cameron <Jonathan.Cameron@huawei.com>]

On Thu, 12 Jun 2025 11:17:52 +0200
Pavel Machek <pavel@ucw.cz> wrote:

> Hi!
> 
> > Jonathan mentioned recently that he would like to get away from using
> > memset() to zero-initialize stack memory in the IIO subsystem. And we
> > have it on good authority that initializing a struct or array with = { }
> > is the preferred way to do this in the kernel [1]. So here is a series
> > to take care of that.  
> 
> 1) Is it worth the churn?
> 
> 2) Will this fail to initialize padding with some obscure compiler?
> 
> 3) Why do you believe that {} is the preffered way? All we have is
> Kees' email that explains that = {} maybe works in configs he tested.
> 
Pavel,

I think main thing that matters in Kees email is there is a self test
that should fire if a compiler ever does this wrong.

Using this syntax is definitely not a 'kernel wide' preference yet
but I do prefer to make some changes like this in IIO just because it
reduces the amount of code that smells different when reviewing.
Given how many drivers we now have, sadly people pick different ones
to cut and paste from so we get a lot of new drivers that look like
how we preferred to do things 10 years ago :(

However it is a fair bit of churn. hmm.  Let's let this sit for
a little while and see if other view points come in.

Thanks 

Jonathan
 

> BR,
> 								Pavel
> 
> > [1]:
> > https://lore.kernel.org/linux-iio/202505090942.48EBF01B@keescook/  
> 
> 
> 
> > ---
> > David Lechner (28):
> >       iio: accel: adxl372: use = { } instead of memset()
> >       iio: accel: msa311: use = { } instead of memset()
> >       iio: adc: dln2-adc: use = { } instead of memset()
> >       iio: adc: mt6360-adc: use = { } instead of memset()
> >       iio: adc: rockchip_saradc: use = { } instead of memset()
> >       iio: adc: rtq6056: use = { } instead of memset()
> >       iio: adc: stm32-adc: use = { } instead of memset()
> >       iio: adc: ti-ads1015: use = { } instead of memset()
> >       iio: adc: ti-ads1119: use = { } instead of memset()
> >       iio: adc: ti-lmp92064: use = { } instead of memset()
> >       iio: adc: ti-tsc2046: use = { } instead of memset()
> >       iio: chemical: scd4x: use = { } instead of memset()
> >       iio: chemical: scd30: use = { } instead of memset()
> >       iio: chemical: sunrise_co2: use = { } instead of memset()
> >       iio: dac: ad3552r: use = { } instead of memset()
> >       iio: imu: inv_icm42600: use = { } instead of memset()
> >       iio: imu: inv_mpu6050: use = { } instead of memset()
> >       iio: light: bh1745: use = { } instead of memset()
> >       iio: light: ltr501: use = { } instead of memset()
> >       iio: light: opt4060: use = { } instead of memset()
> >       iio: light: veml6030: use = { } instead of memset()
> >       iio: magnetometer: af8133j: use = { } instead of memset()
> >       iio: pressure: bmp280: use = { } instead of memset()
> >       iio: pressure: mpl3115: use = { } instead of memset()
> >       iio: pressure: mprls0025pa: use = { } instead of memset()
> >       iio: pressure: zpa2326: use = { } instead of memset()
> >       iio: proximity: irsd200: use = { } instead of memset()
> >       iio: temperature: tmp006: use = { } instead of memset()
> > 
> >  drivers/iio/accel/adxl372.c                       | 3 +--
> >  drivers/iio/accel/msa311.c                        | 4 +---
> >  drivers/iio/adc/dln2-adc.c                        | 4 +---
> >  drivers/iio/adc/mt6360-adc.c                      | 3 +--
> >  drivers/iio/adc/rockchip_saradc.c                 | 4 +---
> >  drivers/iio/adc/rtq6056.c                         | 4 +---
> >  drivers/iio/adc/stm32-adc.c                       | 3 +--
> >  drivers/iio/adc/ti-ads1015.c                      | 4 +---
> >  drivers/iio/adc/ti-ads1119.c                      | 4 +---
> >  drivers/iio/adc/ti-lmp92064.c                     | 4 +---
> >  drivers/iio/adc/ti-tsc2046.c                      | 3 +--
> >  drivers/iio/chemical/scd30_core.c                 | 3 +--
> >  drivers/iio/chemical/scd4x.c                      | 3 +--
> >  drivers/iio/chemical/sunrise_co2.c                | 6 ++----
> >  drivers/iio/dac/ad3552r.c                         | 3 +--
> >  drivers/iio/imu/inv_icm42600/inv_icm42600_accel.c | 5 ++---
> >  drivers/iio/imu/inv_icm42600/inv_icm42600_gyro.c  | 5 ++---
> >  drivers/iio/imu/inv_mpu6050/inv_mpu_acpi.c        | 4 +---
> >  drivers/iio/imu/inv_mpu6050/inv_mpu_ring.c        | 6 ++----
> >  drivers/iio/light/bh1745.c                        | 4 +---
> >  drivers/iio/light/ltr501.c                        | 4 +---
> >  drivers/iio/light/opt4060.c                       | 4 +---
> >  drivers/iio/light/veml6030.c                      | 4 +---
> >  drivers/iio/magnetometer/af8133j.c                | 4 +---
> >  drivers/iio/pressure/bmp280-core.c                | 5 +----
> >  drivers/iio/pressure/mpl3115.c                    | 3 +--
> >  drivers/iio/pressure/mprls0025pa_i2c.c            | 5 +----
> >  drivers/iio/pressure/zpa2326.c                    | 4 +---
> >  drivers/iio/proximity/irsd200.c                   | 3 +--
> >  drivers/iio/temperature/tmp006.c                  | 4 +---
> >  30 files changed, 34 insertions(+), 85 deletions(-)
> > ---
> > base-commit: 4c6073fec2fee4827fa0dd8a4ab4e6f7bbc05ee6
> > change-id: 20250611-iio-zero-init-stack-with-instead-of-memset-0d12d41a7ecb
> > 
> > Best regards,  
>