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

[Rob Herring]

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.

Rob