linux-kernel - Re: [PATCH 04/29] drm/atomic_helper: Skip over NULL private

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Message-ID: <20250902192940.GS13448@pendragon.ideasonboard.com>
Date: Tue, 2 Sep 2025 21:29:40 +0200
From: Laurent Pinchart <laurent.pinchart@...asonboard.com>
To: Thomas Zimmermann <tzimmermann@...e.de>
Cc: Maxime Ripard <mripard@...nel.org>,
	Maarten Lankhorst <maarten.lankhorst@...ux.intel.com>,
	David Airlie <airlied@...il.com>, Simona Vetter <simona@...ll.ch>,
	Andrzej Hajda <andrzej.hajda@...el.com>,
	Neil Armstrong <neil.armstrong@...aro.org>,
	Robert Foss <rfoss@...nel.org>, Jonas Karlman <jonas@...boo.se>,
	Jernej Skrabec <jernej.skrabec@...il.com>,
	Jyri Sarha <jyri.sarha@....fi>,
	Tomi Valkeinen <tomi.valkeinen@...asonboard.com>,
	Devarsh Thakkar <devarsht@...com>, dri-devel@...ts.freedesktop.org,
	linux-kernel@...r.kernel.org
Subject: Re: [PATCH 04/29] drm/atomic_helper: Skip over NULL private_obj
 pointers

On Tue, Sep 02, 2025 at 03:13:30PM +0200, Thomas Zimmermann wrote:
> Am 02.09.25 um 10:32 schrieb Maxime Ripard:
> > Signed-off-by: Maxime Ripard <mripard@...nel.org>
> 
> Reviewed-by: Thomas Zimmermann <tzimmermann@...e.de>
> 
> However, can this happen? Private state objects without state data?

I was going to ask the same. The commit message should explain why.

> > ---
> >   drivers/gpu/drm/drm_atomic.c | 3 +++
> >   1 file changed, 3 insertions(+)
> >
> > diff --git a/drivers/gpu/drm/drm_atomic.c b/drivers/gpu/drm/drm_atomic.c
> > index b356d26faad4acaa25c1fe6f9bd5043b6364ce87..9b198610791d19c7fd276ca59264a961d21caf43 100644
> > --- a/drivers/gpu/drm/drm_atomic.c
> > +++ b/drivers/gpu/drm/drm_atomic.c
> > @@ -295,10 +295,13 @@ void drm_atomic_state_default_clear(struct drm_atomic_state *state)
> >   	}
> >   
> >   	for (i = 0; i < state->num_private_objs; i++) {
> >   		struct drm_private_obj *obj = state->private_objs[i].ptr;
> >   
> > +		if (!obj)
> > +			continue;
> > +
> >   		obj->funcs->atomic_destroy_state(obj,
> >   						 state->private_objs[i].state);
> >   		state->private_objs[i].ptr = NULL;
> >   		state->private_objs[i].state = NULL;
> >   		state->private_objs[i].old_state = NULL;

-- 
Regards,

Laurent Pinchart