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

Dmitry Torokhov
2020-06-25T05:23:28Z

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