drm/nouveau: embed gem object in nouveau_bo

There is no reason to keep the gem object separately allocated. nouveau is
the last user of gem_obj->driver_private, so if we embed it, we can get
rid of 8bytes per gem-object.

The implementation follows the radeon driver. bo->gem is only valid, iff
the bo was created via the gem helpers _and_ iff the user holds a valid
gem reference. That is, as the gem object holds a reference to the
nouveau_bo. If you use nouveau_ref() to gain a bo reference, you are not
guaranteed to also hold a gem reference. The gem object might get
destroyed after the last user drops the gem-ref via
drm_gem_object_unreference(). Use drm_gem_object_reference() to gain a
gem-reference.

For debugging, we can use bo->gem.filp != NULL to test whether a gem-bo is
valid. However, this shouldn't be used for real functionality to avoid
gem-internal dependencies.

Note that the implementation follows the previous style. However, we no
longer can check for bo->gem != NULL to test for a valid gem object. This
wasn't done before, so we should be safe now.

Signed-off-by: David Herrmann <dh.herrmann@gmail.com>
Acked-by: Maarten Lankhorst <maarten.lankhorst@canonical.com>
Reviewed-by: Ben Skeggs <bskeggs@redhat.com>
Signed-off-by: Dave Airlie <airlied@redhat.com>

1 files changed, 2 insertions, 2 deletions

diff --git a/drivers/gpu/drm/nouveau/nouveau_bo.c b/drivers/gpu/drm/nouveau/nouveau_bo.c
index 755c38d06271..4172854d4365 100644
--- a/drivers/gpu/drm/nouveau/nouveau_bo.c
+++ b/drivers/gpu/drm/nouveau/nouveau_bo.c
@@ -146,7 +146,7 @@ nouveau_bo_del_ttm(struct ttm_buffer_object *bo)
         struct drm_device *dev = drm->dev;
         struct nouveau_bo *nvbo = nouveau_bo(bo);
 
-        if (unlikely(nvbo->gem))
+        if (unlikely(nvbo->gem.filp))
                 DRM_ERROR("bo %p still attached to GEM object\n", bo);
         WARN_ON(nvbo->pin_refcnt > 0);
         nv10_bo_put_tile_region(dev, nvbo->tile, NULL);
@@ -1267,7 +1267,7 @@ nouveau_bo_verify_access(struct ttm_buffer_object *bo, struct file *filp)
 {
         struct nouveau_bo *nvbo = nouveau_bo(bo);
 
-        return drm_vma_node_verify_access(&nvbo->gem->vma_node, filp);
+        return drm_vma_node_verify_access(&nvbo->gem.vma_node, filp);
 }
 
 static int