Re: [PATCH] iio: common: scmi_iio: use kcalloc() instead of kzalloc()

[Qianfeng Rong]

在 2025/8/19 17:46, Andy Shevchenko 写道:
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> On Tue, Aug 19, 2025 at 11:56 AM Qianfeng Rong <rongqianfeng@xxxxxxxx> wrote:
> > Replace calls of devm_kzalloc() with devm_kcalloc() in scmi_alloc_iiodev()
> > and scmi_iio_set_sampling_freq_avail() for safer memory allocation with
> > built-in overflow protection.
> While this change is correct...
>
> ...
>
> >          sensor->freq_avail =
> > -               devm_kzalloc(&iio_dev->dev,
> > -                            sizeof(*sensor->freq_avail) *
> > -                                    (sensor->sensor_info->intervals.count * 2),
> > +               devm_kcalloc(&iio_dev->dev,
> > +                            sensor->sensor_info->intervals.count * 2,
> ...I would also switch this to use array_size() instead of explicit
> multiplication as it will check for boundaries that are not static in
> this case.

I don't understand what "will check for boundaries that are not static in
this case" means. Could you explain it to me?

I've experimented with the following command and found that kmalloc_array()
generates fewer instructions than kmalloc(array_size()):
objdump -dSl --prefix-addresses <changed module>.o

> --
> With Best Regards,
> Andy Shevchenko
Best regards,
Qianfeng