[PATCH 1/6] drm/gem: refine drm_gem_objects_lookup

[Qiang Yu]

On Thu, Sep 26, 2019 at 11:01 PM Rob Herring <robh at kernel.org> wrote:
>
> On Thu, Sep 26, 2019 at 9:12 AM Qiang Yu <yuq825 at gmail.com> wrote:
> >
> > Do not use user space bo handles directly and left the user
> > to kernel copy work to drivers calling this function.
> >
> > This is for driver like lima which does not pass gem bo
> > handles continously in an array in ioctl argument.
> >
> > Cc: Rob Herring <robh at kernel.org>
> > Cc: Tomeu Vizoso <tomeu.vizoso at collabora.com>
> > Cc: Steven Price <steven.price at arm.com>
> > Cc: Alyssa Rosenzweig <alyssa.rosenzweig at collabora.com>
> > Signed-off-by: Qiang Yu <yuq825 at gmail.com>
> > ---
> >  drivers/gpu/drm/drm_gem.c               | 28 +++++++------------------
> >  drivers/gpu/drm/panfrost/panfrost_drv.c | 23 +++++++++++++++++---
>
> Please keep the current variant. While only panfrost is converted ATM,
> vc4 and v3d will use this too.
>
> >  include/drm/drm_gem.h                   |  2 +-
> >  3 files changed, 29 insertions(+), 24 deletions(-)
> >
> > diff --git a/drivers/gpu/drm/drm_gem.c b/drivers/gpu/drm/drm_gem.c
> > index 6854f5867d51..9f73e5f3b53f 100644
> > --- a/drivers/gpu/drm/drm_gem.c
> > +++ b/drivers/gpu/drm/drm_gem.c
> > @@ -679,11 +679,11 @@ static int objects_lookup(struct drm_file *filp, u32 *handle, int count,
> >  /**
> >   * drm_gem_objects_lookup - look up GEM objects from an array of handles
> >   * @filp: DRM file private date
> > - * @bo_handles: user pointer to array of userspace handle
> > + * @bo_handles: array of GEM object handles
> >   * @count: size of handle array
> >   * @objs_out: returned pointer to array of drm_gem_object pointers
> >   *
> > - * Takes an array of userspace handles and returns a newly allocated array of
> > + * Takes an array of GEM object handles and returns a newly allocated array of
> >   * GEM objects.
> >   *
> >   * For a single handle lookup, use drm_gem_object_lookup().
> > @@ -695,11 +695,10 @@ static int objects_lookup(struct drm_file *filp, u32 *handle, int count,
> >   * failure. 0 is returned on success.
> >   *
> >   */
> > -int drm_gem_objects_lookup(struct drm_file *filp, void __user *bo_handles,
> > +int drm_gem_objects_lookup(struct drm_file *filp, u32 *bo_handles,
> >                            int count, struct drm_gem_object ***objs_out)
>
> Either split into drm_gem_objects_lookup() and a
> drm_gem_objects_lookup_user() with the latter calling the former or
> just make the helper take both a user and u32* ptr with the
> expectation that only one of them is non-NULL.
>
OK, I prefer the first way, will send v2 for it.

Thanks,
Qiang

> Rob