[PATCH v3 1/2] drm/gem: drm_gem_dumb_map_offset(): reject dma-buf

[Chris Wilson]

Quoting Laurent Pinchart (2017-08-17 18:56:09)
> Hi Noralf,
> 
> Thank you for the patch.
> 
> On Thursday 17 Aug 2017 18:21:30 Noralf Trønnes wrote:
> > Reject mapping an imported dma-buf since is's an invalid use-case.
> > 
> > Cc: Philipp Zabel <p.zabel at pengutronix.de>
> > Cc: Laurent Pinchart <laurent.pinchart at ideasonboard.com>
> > Cc: Sean Paul <seanpaul at chromium.org>
> > Cc: Daniel Vetter <daniel.vetter at ffwll.ch>
> > Signed-off-by: Noralf Trønnes <noralf at tronnes.org>
> > ---
> >  drivers/gpu/drm/drm_gem.c | 6 ++++++
> >  1 file changed, 6 insertions(+)
> > 
> > diff --git a/drivers/gpu/drm/drm_gem.c b/drivers/gpu/drm/drm_gem.c
> > index ad4e9cf..8da5801 100644
> > --- a/drivers/gpu/drm/drm_gem.c
> > +++ b/drivers/gpu/drm/drm_gem.c
> > @@ -333,6 +333,12 @@ int drm_gem_dumb_map_offset(struct drm_file *file,
> > struct drm_device *dev, if (!obj)
> >               return -ENOENT;
> > 
> > +     /* Don't allow imported objects to be mapped */
> > +     if (obj->import_attach) {
> > +             ret = -EINVAL;
> > +             goto out;
> > +     }
> > +
> 
> Wouldn't it be better to move this check to drm_gem_create_mmap_offset_size() 
> to reject mapping of all imported dmabuf, not just the ones associated with 
> dumb buffers ?

No, we use that and we don't ban mapping an imported object.
-Chris