[Intel-gfx] [PATCH 19/52] drm/<drivers>: Use drmm_add_final_kfree

[Daniel Vetter]

On Wed, Feb 19, 2020 at 3:39 PM Laurent Pinchart
<laurent.pinchart at ideasonboard.com> wrote:
>
> Hi Daniel,
>
> On Wed, Feb 19, 2020 at 03:30:59PM +0100, Daniel Vetter wrote:
> > On Wed, Feb 19, 2020 at 3:11 PM Laurent Pinchart wrote:
> > > On Wed, Feb 19, 2020 at 11:20:49AM +0100, Daniel Vetter wrote:
> > > > These are the leftover drivers that didn't have a ->release hook that
> > > > needed to be updated.
> > > >
> > > > Signed-off-by: Daniel Vetter <daniel.vetter at intel.com>
> > > > Cc: "James (Qian) Wang" <james.qian.wang at arm.com>
> > > > Cc: Liviu Dudau <liviu.dudau at arm.com>
> > > > Cc: Mihail Atanassov <mihail.atanassov at arm.com>
> > > > Cc: Russell King <linux at armlinux.org.uk>
> > > > Cc: Hans de Goede <hdegoede at redhat.com>
> > > > ---
> > > >  drivers/gpu/drm/arm/display/komeda/komeda_kms.c | 2 ++
> > > >  drivers/gpu/drm/armada/armada_drv.c             | 2 ++
> > > >  drivers/gpu/drm/vboxvideo/vbox_drv.c            | 2 ++
> > > >  3 files changed, 6 insertions(+)
> > > >
> > > > diff --git a/drivers/gpu/drm/arm/display/komeda/komeda_kms.c b/drivers/gpu/drm/arm/display/komeda/komeda_kms.c
> > > > index 442d4656150a..16dfd5cdb66c 100644
> > > > --- a/drivers/gpu/drm/arm/display/komeda/komeda_kms.c
> > > > +++ b/drivers/gpu/drm/arm/display/komeda/komeda_kms.c
> > > > @@ -14,6 +14,7 @@
> > > >  #include <drm/drm_gem_cma_helper.h>
> > > >  #include <drm/drm_gem_framebuffer_helper.h>
> > > >  #include <drm/drm_irq.h>
> > > > +#include <drm/drm_managed.h>
> > > >  #include <drm/drm_probe_helper.h>
> > > >  #include <drm/drm_vblank.h>
> > > >
> > > > @@ -271,6 +272,7 @@ struct komeda_kms_dev *komeda_kms_attach(struct komeda_dev *mdev)
> > > >       err = drm_dev_init(drm, &komeda_kms_driver, mdev->dev);
> > > >       if (err)
> > > >               goto free_kms;
> > > > +     drmm_add_final_kfree(drm, kms);
> > >
> > > Instead of sprinkling calls to drmm_add_final_kfree() everywhere,
> > > wouldn't it be better to pass the parent pointer to drm_dev_init() ?
> >
> > Would lead to a horrendous monster patch, and even with this splitting
> > there were a few corner cases.
>
> It could be generated by coccinelle, with the semantic patch included in
> the commit message, so that regenerating it should be possible when
> merging if conflict arise.

It's not that easy, because drivers are buggy. So you need to review
the remove/release implementation for all of them (which I've done) to
make sure you're not making things worse with some additional
use-after-free or something else horrible. That's why this is so much
split up.

So automated patch for this is out of the window imo.
-Daniel

> > My plan is to add a devm_drm_dev_alloc
> > pattern which combines the usual pattern that most drivers use, see
> > the last patch for all these glorious ideas.
>
> OK I will.
>
> > So yeah I hope this will all go away (or mostly at least), but for
> > bisecting I didn't come up with a better idea to get this all off the
> > ground unfortunately.
> >
> > > >
> > > >       drm->dev_private = mdev;
> > > >
> > > > diff --git a/drivers/gpu/drm/armada/armada_drv.c b/drivers/gpu/drm/armada/armada_drv.c
> > > > index 197dca3fc84c..dd9ed71ed942 100644
> > > > --- a/drivers/gpu/drm/armada/armada_drv.c
> > > > +++ b/drivers/gpu/drm/armada/armada_drv.c
> > > > @@ -12,6 +12,7 @@
> > > >  #include <drm/drm_atomic_helper.h>
> > > >  #include <drm/drm_drv.h>
> > > >  #include <drm/drm_ioctl.h>
> > > > +#include <drm/drm_managed.h>
> > > >  #include <drm/drm_prime.h>
> > > >  #include <drm/drm_probe_helper.h>
> > > >  #include <drm/drm_fb_helper.h>
> > > > @@ -103,6 +104,7 @@ static int armada_drm_bind(struct device *dev)
> > > >               kfree(priv);
> > > >               return ret;
> > > >       }
> > > > +     drmm_add_final_kfree(&priv->drm, priv);
> > > >
> > > >       /* Remove early framebuffers */
> > > >       ret = drm_fb_helper_remove_conflicting_framebuffers(NULL,
> > > > diff --git a/drivers/gpu/drm/vboxvideo/vbox_drv.c b/drivers/gpu/drm/vboxvideo/vbox_drv.c
> > > > index 8512d970a09f..13eaae7921f5 100644
> > > > --- a/drivers/gpu/drm/vboxvideo/vbox_drv.c
> > > > +++ b/drivers/gpu/drm/vboxvideo/vbox_drv.c
> > > > @@ -17,6 +17,7 @@
> > > >  #include <drm/drm_fb_helper.h>
> > > >  #include <drm/drm_file.h>
> > > >  #include <drm/drm_ioctl.h>
> > > > +#include <drm/drm_managed.h>
> > > >
> > > >  #include "vbox_drv.h"
> > > >
> > > > @@ -54,6 +55,7 @@ static int vbox_pci_probe(struct pci_dev *pdev, const struct pci_device_id *ent)
> > > >       vbox->ddev.pdev = pdev;
> > > >       vbox->ddev.dev_private = vbox;
> > > >       pci_set_drvdata(pdev, vbox);
> > > > +     drmm_add_final_kfree(&vbox->ddev, vbox);
> > > >       mutex_init(&vbox->hw_mutex);
> > > >
> > > >       ret = pci_enable_device(pdev);
>
> --
> Regards,
>
> Laurent Pinchart



-- 
Daniel Vetter
Software Engineer, Intel Corporation
+41 (0) 79 365 57 48 - http://blog.ffwll.ch