[PATCH] drm/tegra: don't take dev->struct_mutex in mmap offset ioctl

[Patrik Jakobsson]

On Thu, Oct 15, 2015 at 2:35 PM, Daniel Vetter <daniel.vetter at ffwll.ch> wrote:
> Since David Herrmann's mmap vma manager rework we don't need to grab
> dev->struct_mutex any more to prevent races when looking up the mmap
> offset. Drop it and instead don't forget to use the unref_unlocked
> variant (since the drm core still cares).
>
> v2: Finally get rid of the copypasta from another commit in this
> commit message. And convert to _unlocked like we need to (Patrik).
>
> Cc: Patrik Jakobsson <patrik.r.jakobsson at gmail.com>
> Cc: Thierry Reding <thierry.reding at gmail.com>
> Signed-off-by: Daniel Vetter <daniel.vetter at intel.com>

Reviewed-by: Patrik Jakobsson <patrik.r.jakobsson at gmail.com>

> ---
>  drivers/gpu/drm/tegra/gem.c | 7 +------
>  1 file changed, 1 insertion(+), 6 deletions(-)
>
> diff --git a/drivers/gpu/drm/tegra/gem.c b/drivers/gpu/drm/tegra/gem.c
> index 01e16e146bfe..fb712316c522 100644
> --- a/drivers/gpu/drm/tegra/gem.c
> +++ b/drivers/gpu/drm/tegra/gem.c
> @@ -408,12 +408,9 @@ int tegra_bo_dumb_map_offset(struct drm_file *file, struct drm_device *drm,
>         struct drm_gem_object *gem;
>         struct tegra_bo *bo;
>
> -       mutex_lock(&drm->struct_mutex);
> -
>         gem = drm_gem_object_lookup(drm, file, handle);
>         if (!gem) {
>                 dev_err(drm->dev, "failed to lookup GEM object\n");
> -               mutex_unlock(&drm->struct_mutex);
>                 return -EINVAL;
>         }
>
> @@ -421,9 +418,7 @@ int tegra_bo_dumb_map_offset(struct drm_file *file, struct drm_device *drm,
>
>         *offset = drm_vma_node_offset_addr(&bo->gem.vma_node);
>
> -       drm_gem_object_unreference(gem);
> -
> -       mutex_unlock(&drm->struct_mutex);
> +       drm_gem_object_unreference_unlocked(gem);
>
>         return 0;
>  }
> --
> 2.5.1
>