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SubjectRe: [PATCH 1/3] drm: rcar-du: add missing of_node_put


On Mon, 14 Jan 2019, Kieran Bingham wrote:

> Hi Julia,
>
> Thank you for the patch,
>
> On 13/01/2019 09:44, Julia Lawall wrote:
> > Add an of_node_put when the result of of_graph_get_remote_port_parent is
> > not available.
> >
> > The semantic match that finds this problem is as follows
> > (http://coccinelle.lip6.fr):
> >
> > // <smpl>
> > @r exists@
> > local idexpression e;
> > expression x;
> > @@
> > e = of_graph_get_remote_port_parent(...);
> > ... when != x = e
> > when != true e == NULL
> > when != of_node_put(e)
> > when != of_fwnode_handle(e)
> > (
> > return e;
> > |
> > *return ...;
> > )
> > // </smpl>
> >
>
> For this part at least:
>
> Reviewed-by: Kieran Bingham <kieran.bingham+renesas@ideasonboard.com>
>
> But a little discussion below:
>
>
> > Signed-off-by: Julia Lawall <Julia.Lawall@lip6.fr>
>
> This does indeed look like a missing of_node_put() but I don't think it
> will be the only one in that code. It gets a bit tangled - and I think
> there's possibly another missing put on the error path of
>
> if (!encoder) {
> dev_warn(rcdu->dev,
> "no encoder found for endpoint %pOF, skipping\n",
> ep->local_node);
> return -ENODEV;
> }
>
> because that implies that no encoder was found, and thus -
> encoder = entity;
>
> was not executed, and the tail of that function calls:
>
> of_node_put(encoder);
>
> which would have been the final of_node_put(entity)

Looking at it again, I agree. I can just extend this patch.

julia


>
>
> I think that part could be considered separate to this patch, but it's
> also quite closely related. Either way - I think it needs a second pair
> of eyes to see if I'm not crazy :)
>
> Regards
>
> Kieran
>
> >
> > ---
> > drivers/gpu/drm/rcar-du/rcar_du_kms.c | 1 +
> > 1 file changed, 1 insertion(+)
> >
> > diff --git a/drivers/gpu/drm/rcar-du/rcar_du_kms.c b/drivers/gpu/drm/rcar-du/rcar_du_kms.c
> > index 9c7007d..bc3fcb3 100644
> > --- a/drivers/gpu/drm/rcar-du/rcar_du_kms.c
> > +++ b/drivers/gpu/drm/rcar-du/rcar_du_kms.c
> > @@ -331,6 +331,7 @@ static int rcar_du_encoders_init_one(struct rcar_du_device *rcdu,
> > dev_dbg(rcdu->dev,
> > "connected entity %pOF is disabled, skipping\n",
> > entity);
> > + of_node_put(entity);
> > return -ENODEV;
> > }
> >
> >
>
>

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