On Mon, Mar 30, 2026 at 1:46 AM Andy Shevchenko
<andy.shevchenko@gmail.com> wrote:
>
> On Sat, Mar 28, 2026 at 9:17 PM Rosen Penev <rosenp@gmail.com> wrote:
> >
> > Simplifies allocations by using a flexible array member in this struct.
> >
> > Remove hsu_dma_alloc_desc(). It now offers no readability advantages in
> > this single usage.
> >
> > Add __counted_by to get extra runtime analysis.
>
> > Apply the exact same treatment to struct hsu_dma and devm_kzalloc.
>
> We refer to the functions as func(): devm_kzalloc().
>
> ...
>
> > -       hsu = devm_kzalloc(chip->dev, sizeof(*hsu), GFP_KERNEL);
> > +       /* Calculate nr_channels from the IO space length */
> > +       nr_channels = (chip->length - chip->offset) / HSU_DMA_CHAN_LENGTH;
> > +       hsu = devm_kzalloc(chip->dev, struct_size(hsu, chan, nr_channels), GFP_KERNEL);
> >         if (!hsu)
> >                 return -ENOMEM;
> >
> > -       chip->hsu = hsu;
> > -
> > -       /* Calculate nr_channels from the IO space length */
> > -       hsu->nr_channels = (chip->length - chip->offset) / HSU_DMA_CHAN_LENGTH;
> > +       hsu->nr_channels = nr_channels;
> >
> > -       hsu->chan = devm_kcalloc(chip->dev, hsu->nr_channels,
> > -                                sizeof(*hsu->chan), GFP_KERNEL);
> > -       if (!hsu->chan)
> > -               return -ENOMEM;
> > +       chip->hsu = hsu;
>
> Don't know these _flex() APIs enough, but can we leave the chip->hsu =
> hsu; in the same place as it's now?
__counted_by requires the first assignment after allocation to be the
counting variable. The _flex macros do this automatically for GCC15
and above.
>
> --
> With Best Regards,
> Andy Shevchenko