[Intel-gfx] [PATCH] drm/i915/gem: Hook user-extensions upto MMAP_OFFSET_IOCTL

[Matthew Auld]

On Wed, 4 Dec 2019 at 17:24, Chris Wilson <chris at chris-wilson.co.uk> wrote:
>
> Quoting Matthew Auld (2019-12-04 16:52:12)
> > On Wed, 4 Dec 2019 at 16:29, Chris Wilson <chris at chris-wilson.co.uk> wrote:
> > >
> > > From: Chris Wilson <ickle at braswell.alporthouse.com>
> > >
> > > Call i915_user_extensions() to validate the arg->extensions pointer, and
> > > so return consistent error numbers for the future.
> > >
> > > Signed-off-by: Chris Wilson <chris at chris-wilson.co.uk>
> > > Cc: Abdiel Janulgue <abdiel.janulgue at linux.intel.com>
> > > Cc: Matthew Auld <matthew.auld at intel.com>
> > > ---
> > >  drivers/gpu/drm/i915/gem/i915_gem_mman.c | 8 ++++++--
> > >  1 file changed, 6 insertions(+), 2 deletions(-)
> > >
> > > diff --git a/drivers/gpu/drm/i915/gem/i915_gem_mman.c b/drivers/gpu/drm/i915/gem/i915_gem_mman.c
> > > index 37aabbfa869a..3a3f30bc8ac7 100644
> > > --- a/drivers/gpu/drm/i915/gem/i915_gem_mman.c
> > > +++ b/drivers/gpu/drm/i915/gem/i915_gem_mman.c
> > > @@ -17,6 +17,7 @@
> > >  #include "i915_gem_object.h"
> > >  #include "i915_gem_mman.h"
> > >  #include "i915_trace.h"
> > > +#include "i915_user_extensions.h"
> > >  #include "i915_vma.h"
> > >
> > >  static inline bool
> > > @@ -617,9 +618,12 @@ i915_gem_mmap_offset_ioctl(struct drm_device *dev, void *data,
> > >         struct drm_i915_private *i915 = to_i915(dev);
> > >         struct drm_i915_gem_mmap_offset *args = data;
> > >         enum i915_mmap_type type;
> > > +       int err;
> > >
> > > -       if (args->extensions)
> > > -               return -EINVAL;
> > > +       err = i915_user_extensions(u64_to_user_ptr(args->extensions),
> > > +                                  NULL, 0, NULL);
> > > +       if (err)
> > > +               return err;
> >
> > Don't we have to check get_user first on the ptr?
>
> No, it's checked by i915_user_extensions(). It's a bit redundant in the
> other callers :) Since the first thing we do is while (ext).
>
> I have some memory of starting out with NULL being an error for
> i915_user_extensions, but we settled on while(ext) for a compact
> non-recursive loop.

Reviewed-by: Matthew Auld <matthew.auld at intel.com>

> -Chris