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

[Qianfeng Rong]

在 2025/8/19 18:13, Andy Shevchenko 写道:
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>
> On Tue, Aug 19, 2025 at 1:08 PM Qianfeng Rong <rongqianfeng@xxxxxxxx> wrote:
> > 在 2025/8/19 17:46, Andy Shevchenko 写道:
> > > On Tue, Aug 19, 2025 at 11:56 AM Qianfeng Rong <rongqianfeng@xxxxxxxx> wrote:
> ...
>
> > > 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?
> intervals.count may be anything and of any type. Compiler may or may
> not proof that it holds the value less than size_t / 2 (which may be
> == int / 2 on 32-bit platforms). That's why it's better to use
> array_size(intervals.count, 2),
Sorry, I just understood your reply, I will send v2 immediately.  :)
> > 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
> It's about the second parameter in devm_kcalloc(), and of course it
> may generate less instructions but it's irrelevant to my comment.
Best regards,
Qianfeng