linux-kernel - Re: [linux-sunxi] [PATCH 3/3] drm/sun4i: Fix component unbinding and component master deletion

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Message-ID: <db33cf62349f13dbb6e1eaa7dc970df97d2cb257.camel@bootlin.com>
Date:   Thu, 18 Apr 2019 19:23:05 +0200
From:   Paul Kocialkowski <paul.kocialkowski@...tlin.com>
To:     Chen-Yu Tsai <wens@...e.org>
Cc:     dri-devel <dri-devel@...ts.freedesktop.org>,
        linux-arm-kernel <linux-arm-kernel@...ts.infradead.org>,
        linux-kernel <linux-kernel@...r.kernel.org>,
        linux-sunxi <linux-sunxi@...glegroups.com>,
        Maxime Ripard <maxime.ripard@...tlin.com>,
        David Airlie <airlied@...ux.ie>,
        Daniel Vetter <daniel@...ll.ch>,
        Thomas Petazzoni <thomas.petazzoni@...tlin.com>
Subject: Re: [linux-sunxi] [PATCH 3/3] drm/sun4i: Fix component unbinding
 and component master deletion

Hi,

Le jeudi 18 avril 2019 à 08:03 -0700, Chen-Yu Tsai a écrit :
> On Thu, Apr 18, 2019 at 6:27 AM Paul Kocialkowski
> <paul.kocialkowski@...tlin.com> wrote:
> > For our component-backed driver to be properly removed, we need to
> > delete the component master in sun4i_drv_remove and make sure to call
> > component_unbind_all in the master's unbind so that all components are
> > unbound when the master is.
> > 
> > Fixes: 9026e0d122ac ("drm: Add Allwinner A10 Display Engine support")
> > Signed-off-by: Paul Kocialkowski <paul.kocialkowski@...tlin.com>
> > ---
> >  drivers/gpu/drm/sun4i/sun4i_drv.c | 4 ++++
> >  1 file changed, 4 insertions(+)
> > 
> > diff --git a/drivers/gpu/drm/sun4i/sun4i_drv.c b/drivers/gpu/drm/sun4i/sun4i_drv.c
> > index af07291544a4..0ea365e54de1 100644
> > --- a/drivers/gpu/drm/sun4i/sun4i_drv.c
> > +++ b/drivers/gpu/drm/sun4i/sun4i_drv.c
> > @@ -137,6 +137,8 @@ static void sun4i_drv_unbind(struct device *dev)
> >         drm_mode_config_cleanup(drm);
> >         of_reserved_mem_device_release(dev);
> >         drm_dev_put(drm);
> > +
> > +       component_unbind_all(dev, NULL);
> 
> Shouldn't this be before drm_dev_put? Everything being in reverse order
> of the complement calls in the bind function and all. The component
> drivers might still be using the drm dev before they are unbound.

Mhh, yes that's a valid concern, thanks for pointing it out. I'll send
out a fix for it tomorrow.

Cheers,

Paul

> ChenYu
> 
> >  }
> > 
> >  static const struct component_master_ops sun4i_drv_master_ops = {
> > @@ -385,6 +387,8 @@ static int sun4i_drv_probe(struct platform_device *pdev)
> > 
> >  static int sun4i_drv_remove(struct platform_device *pdev)
> >  {
> > +       component_master_del(&pdev->dev, &sun4i_drv_master_ops);
> > +
> >         return 0;
> >  }
> > 
> > --
> > 2.21.0
> > 
> > --
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