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From: =?UTF-8?q?Ilpo=20J=C3=A4rvinen?= <ilpo.jarvinen@linux.intel.com>
Date: Mon, 19 Feb 2024 13:57:01 +0200 (EET)
To: Armin Wolf <W_Armin@gmx.de>
cc: =?ISO-8859-15?Q?Ilpo_J=E4rvinen?= <ilpo.jarvinen@linux.intel.com>, 
    corentin.chary@gmail.com, luke@ljones.dev, 
    Hans de Goede <hdegoede@redhat.com>, platform-driver-x86@vger.kernel.org, 
    LKML <linux-kernel@vger.kernel.org>
Subject: Re: [PATCH 2/5] platform/x86: wmi: Check if event data is not NULL
In-Reply-To: <80bc19ce-7111-4a5d-b875-2712bdf2bb72@gmx.de>
Message-ID: <1fb172ff-b085-185e-90ea-1cd131f42b84@linux.intel.com>
References: <20240214070433.2677-1-W_Armin@gmx.de> <20240214070433.2677-3-W_Armin@gmx.de> <e03b600e-6ad2-1dd1-c4af-56ebfce51f12@linux.intel.com> <80bc19ce-7111-4a5d-b875-2712bdf2bb72@gmx.de>
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On Thu, 15 Feb 2024, Armin Wolf wrote:

> Am 15.02.24 um 13:31 schrieb Ilpo J=C3=A4rvinen:
>=20
> > On Wed, 14 Feb 2024, Armin Wolf wrote:
> >=20
> > > WMI event drivers which do not have no_notify_data set expect
> > > that each WMI event contains valid data. Evaluating _WED however
> > > might return no data, which can cause issues with such drivers.
> > >=20
> > > Fix this by validating that evaluating _WED did return data.
> > >=20
> > > Signed-off-by: Armin Wolf <W_Armin@gmx.de>
> > > ---
> > >   drivers/platform/x86/wmi.c | 11 +++++++++--
> > >   1 file changed, 9 insertions(+), 2 deletions(-)
> > >=20
> > > diff --git a/drivers/platform/x86/wmi.c b/drivers/platform/x86/wmi.c
> > > index 34d8f55afaad..8a916887c546 100644
> > > --- a/drivers/platform/x86/wmi.c
> > > +++ b/drivers/platform/x86/wmi.c
> > > @@ -1211,6 +1211,7 @@ static void wmi_notify_driver(struct wmi_block
> > > *wblock)
> > >   {
> > >   =09struct wmi_driver *driver =3D drv_to_wdrv(wblock->dev.dev.driver=
);
> > >   =09struct acpi_buffer data =3D { ACPI_ALLOCATE_BUFFER, NULL };
> > > +=09union acpi_object *obj =3D NULL;
> > >   =09acpi_status status;
> > >=20
> > >   =09if (!driver->no_notify_data) {
> > > @@ -1219,12 +1220,18 @@ static void wmi_notify_driver(struct wmi_bloc=
k
> > > *wblock)
> > >   =09=09=09dev_warn(&wblock->dev.dev, "Failed to get event
> > > data\n");
> > >   =09=09=09return;
> > >   =09=09}
> > > +
> > > +=09=09obj =3D data.pointer;
> > > +=09=09if (!obj) {
> > > +=09=09=09dev_warn(&wblock->dev.dev, "Event contains not event
> > > data\n");
> > > +=09=09=09return;
> > > +=09=09}
> > >   =09}
> > >=20
> > >   =09if (driver->notify)
> > > -=09=09driver->notify(&wblock->dev, data.pointer);
> > > +=09=09driver->notify(&wblock->dev, obj);
> > >=20
> > > -=09kfree(data.pointer);
> > > +=09kfree(obj);
> > Hi Armin,
> >=20
> > While looking into this patch, I failed to connect the mention of
> > no_notify_data in the commit message with the code change that does
> > nothing differently based no_notify_data being set or not, AFAICT.
> >=20
> > It could be just that you need to explain things better in the commit
> > message, I'm not sure.
>=20
> Here the _WED ACPI control method is only evaluated if driver->no_notify_=
data
> is not set.
> So the returned ACPI object should only be validated in this case, as we =
pass
> NULL otherwise.

Yes, I'm sorry, it seems fine. For some reason I was very confused while=20
reviewing even if no_notify_data was mentioned right in the previous=20
context (maybe Iused some older version of the code while trying to figure=
=20
things out, I dunno).

--=20
 i.

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