Re: [PATCH v4 3/7] ACPI: button: Access input device's users under appropriate mutex

[Dmitry Torokhov <dmitry.torokhov@gmail.com>]

On Wed, Jun 24, 2020 at 05:00:09PM +0200, Rafael J. Wysocki wrote:
> On Mon, Jun 8, 2020 at 1:22 PM Andrzej Pietrasiewicz
> <andrzej.p@collabora.com> wrote:
> >
> > Inspecting input device's 'users' member should be done under device's
> > mutex, so add appropriate invocations.
> >
> > Signed-off-by: Andrzej Pietrasiewicz <andrzej.p@collabora.com>
> 
> This looks like a fix that might be applied independently of the other
> patches in the series.
> 
> Do you want me to pick it up?

If you pick it we'll have to have a dance with this series. Can I apply
instead?

I do not think this change has any practical effect as nobody
attaches/detached input handlers or opening/closing input devices when
system goes through device resume phase.

> 
> > ---
> >  drivers/acpi/button.c | 5 ++++-
> >  1 file changed, 4 insertions(+), 1 deletion(-)
> >
> > diff --git a/drivers/acpi/button.c b/drivers/acpi/button.c
> > index 78cfc70cb320..ff7ab291f678 100644
> > --- a/drivers/acpi/button.c
> > +++ b/drivers/acpi/button.c
> > @@ -456,13 +456,16 @@ static int acpi_button_resume(struct device *dev)
> >  {
> >         struct acpi_device *device = to_acpi_device(dev);
> >         struct acpi_button *button = acpi_driver_data(device);
> > +       struct input_dev *input = button->input;
> >
> >         button->suspended = false;
> > -       if (button->type == ACPI_BUTTON_TYPE_LID && button->input->users) {
> > +       mutex_lock(&input->mutex);
> > +       if (button->type == ACPI_BUTTON_TYPE_LID && input->users) {
> >                 button->last_state = !!acpi_lid_evaluate_state(device);
> >                 button->last_time = ktime_get();
> >                 acpi_lid_initialize_state(device);
> >         }
> > +       mutex_unlock(&input->mutex);
> >         return 0;
> >  }
> >  #endif
> > --
> > 2.17.1
> >

Thanks.

-- 
Dmitry