Re: [PATCH] gpio: ljca: reduce struct allocation

[Sakari Ailus]

Hi Rosen,

On Sun, Mar 08, 2026 at 11:54:07AM -0700, Rosen Penev wrote:
> On Sun, Mar 8, 2026 at 5:19 AM Sakari Ailus
> <sakari.ailus@xxxxxxxxxxxxxxx> wrote:
> >
> > Hi Rosen,
> >
> > Thanks or the patch.
> >
> > On Sat, Mar 07, 2026 at 06:12:01PM -0800, Rosen Penev wrote:
> > > Convert connect_mode to a flexible array member to avoid calling
> > > kcalloc and to combine the allocations.
> > >
> > > Signed-off-by: Rosen Penev <rosenp@xxxxxxxxx>
> > > ---
> > >  drivers/gpio/gpio-ljca.c | 16 +++++++---------
> > >  1 file changed, 7 insertions(+), 9 deletions(-)
> > >
> > > diff --git a/drivers/gpio/gpio-ljca.c b/drivers/gpio/gpio-ljca.c
> > > index f32d1d237795..a531aaa0425f 100644
> > > --- a/drivers/gpio/gpio-ljca.c
> > > +++ b/drivers/gpio/gpio-ljca.c
> > > @@ -63,7 +63,6 @@ struct ljca_gpio_dev {
> > >       DECLARE_BITMAP(enabled_irqs, LJCA_MAX_GPIO_NUM);
> > >       DECLARE_BITMAP(reenable_irqs, LJCA_MAX_GPIO_NUM);
> > >       DECLARE_BITMAP(output_enabled, LJCA_MAX_GPIO_NUM);
> > > -     u8 *connect_mode;
> > >       /* protect irq bus */
> > >       struct mutex irq_lock;
> > >       struct work_struct work;
> > > @@ -72,6 +71,8 @@ struct ljca_gpio_dev {
> > >
> > >       u8 obuf[LJCA_GPIO_BUF_SIZE];
> > >       u8 ibuf[LJCA_GPIO_BUF_SIZE];
> > > +
> > > +     u8 connect_mode[];
> > >  };
> > >
> > >  static int ljca_gpio_config(struct ljca_gpio_dev *ljca_gpio, u8 gpio_id,
> > > @@ -400,22 +401,19 @@ static int ljca_gpio_probe(struct auxiliary_device *auxdev,
> > >                          const struct auxiliary_device_id *aux_dev_id)
> > >  {
> > >       struct ljca_client *ljca = auxiliary_dev_to_ljca_client(auxdev);
> > > +     struct ljca_gpio_info *gpio_info;
> > >       struct ljca_gpio_dev *ljca_gpio;
> > >       struct gpio_irq_chip *girq;
> > >       int ret;
> > >
> > > -     ljca_gpio = devm_kzalloc(&auxdev->dev, sizeof(*ljca_gpio), GFP_KERNEL);
> > > +     gpio_info = dev_get_platdata(&auxdev->dev);
> >
> > You can do this assignment in variable declaration.
> I avoided doing so to keep reverse christmas tree order. I can still
> do so if desired.

How does that affect it? There doesn't seem to be a dependency here -- and
even if there was, the dependency obviously has priority.

> >
> > > +     ljca_gpio = devm_kzalloc(&auxdev->dev, struct_size(ljca_gpio, connect_mode, gpio_info->num),
> >
> > This line is a bit long, I'd wrap it.
> Will fix.
> >
> > > +                              GFP_KERNEL);
> > >       if (!ljca_gpio)
> > >               return -ENOMEM;
> > >
> > >       ljca_gpio->ljca = ljca;
> > > -     ljca_gpio->gpio_info = dev_get_platdata(&auxdev->dev);
> > > -     ljca_gpio->connect_mode = devm_kcalloc(&auxdev->dev,
> > > -                                            ljca_gpio->gpio_info->num,
> > > -                                            sizeof(*ljca_gpio->connect_mode),
> > > -                                            GFP_KERNEL);
> > > -     if (!ljca_gpio->connect_mode)
> > > -             return -ENOMEM;
> > > +     ljca_gpio->gpio_info = gpio_info;
> > >
> > >       ret = devm_mutex_init(&auxdev->dev, &ljca_gpio->irq_lock);
> > >       if (ret)
> >

-- 
Kind regards,

Sakari Ailus