RE: [PATCH 2/2] media: v4l: vsp1: Fix uif null pointer access

[Biju Das <biju.das.jz@bp.renesas.com>]

Hi Laurent,

Thanks for the feedback.

> -----Original Message-----
> From: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
> Sent: 15 March 2021 03:43
> To: Biju Das <biju.das.jz@bp.renesas.com>
> Cc: kieran.bingham+renesas@ideasonboard.com; Mauro Carvalho Chehab
> <mchehab@kernel.org>; linux-media@vger.kernel.org; linux-renesas-
> soc@vger.kernel.org; Geert Uytterhoeven <geert+renesas@glider.be>; Chris
> Paterson <Chris.Paterson2@renesas.com>; Biju Das
> <biju.das@bp.renesas.com>; Prabhakar Mahadev Lad <prabhakar.mahadev-
> lad.rj@bp.renesas.com>; Hans Verkuil <hverkuil-cisco@xs4all.nl>
> Subject: Re: [PATCH 2/2] media: v4l: vsp1: Fix uif null pointer access
> 
> Hi Biju,
> 
> On Wed, Mar 10, 2021 at 02:50:23PM +0000, Biju Das wrote:
> > > On 10/03/2021 13:56, Biju Das wrote:
> > > > Thanks for the feedback.
> > > >> Subject: Re: [PATCH 2/2] media: v4l: vsp1: Fix uif null pointer
> > > >> access
> > > >>
> > > >> Hi Biju,
> > > >>
> > > >> On 01/03/2021 12:08, Biju Das wrote:
> > > >>> RZ/G2L SoC has no UIF. This patch fixes null pointer access,
> > > >>> when UIF module is not used.
> > > >>>
> > > >>> Fixes: 5e824f989e6e8("media: v4l: vsp1: Integrate DISCOM in
> > > >>> display
> > > >>> pipeline")
> > > >>> Signed-off-by: Biju Das <biju.das.jz@bp.renesas.com>
> > > >>> ---
> > > >>>  drivers/media/platform/vsp1/vsp1_drm.c | 4 ++--
> > > >>>  1 file changed, 2 insertions(+), 2 deletions(-)
> > > >>>
> > > >>> diff --git a/drivers/media/platform/vsp1/vsp1_drm.c
> > > >>> b/drivers/media/platform/vsp1/vsp1_drm.c
> > > >>> index f6d2f47a4058..06f74d410973 100644
> > > >>> --- a/drivers/media/platform/vsp1/vsp1_drm.c
> > > >>> +++ b/drivers/media/platform/vsp1/vsp1_drm.c
> > > >>> @@ -462,9 +462,9 @@ static int
> > > >>> vsp1_du_pipeline_setup_inputs(struct
> > > >>> vsp1_device *vsp1,
> > > >>
> > > >>
> > > >> This looks like it complicates these conditionals more than we
> > > >> perhaps need to.
> > > >>
> > > >> What do you think about adding something above the block comment
> here?:
> > > >
> > > > It is much better.
> > > >
> > > > This patch is accepted in media tree[1]. So not sure, should I
> > > > send a follow up patch as optimization or drop this patch and send
> new one.
> > >
> > > Oh, I didn't realise these were in already. Sorry, I didn't see any
> > > review on the list, and it was the earliest I had got to them.
> > >
> > > > Please suggest.
> > >
> > > Up to you, I don't think this would get dropped now it's integrated.
> > > It's in, so if you want to update on top I believe that's fine.
> >
> > OK, Will send follow up patch as optimization.
> 
> That would be nice.
> 
> I don't think this patch should have been fast-tracked as a fix, as RZ/G2L
> isn't supported in mainline yet as far as I can tell.


Please correct me, if I am wrong. We have pluggable modules in VSP and with routing
Register we can achieve any combination with the VSP driver we have. 

If it is the case, it is a bug which is fast-tracked as a fix. Otherwise(ie, driver doesn't have flexibility to support pluggable feature) I am agreeing with your statement.

Cheers,
Biju

> Hans, next time, could we get a notification instead of a silent merge ?
> 
> > > >> 	if (!drm_pipe->uif)
> > > >> 		return 0;
> > > >>
> > > >>
> > > >>>  	 * make sure it is present in the pipeline's list of entities
> if it
> > > >>>  	 * wasn't already.
> > > >>>  	 */
> > > >>> -	if (!use_uif) {
> > > >>> +	if (drm_pipe->uif && !use_uif) {
> > > >>>  		drm_pipe->uif->pipe = NULL;
> > > >>> -	} else if (!drm_pipe->uif->pipe) {
> > > >>> +	} else if (drm_pipe->uif && !drm_pipe->uif->pipe) {>
> > > >> 	drm_pipe->uif->pipe = pipe;
> > > >>>  		list_add_tail(&drm_pipe->uif->list_pipe, &pipe-
> >entities);
> > > >>>  	}
> > > >>>
> 
> --
> Regards,
> 
> Laurent Pinchart