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, 5 insertions, 5 deletions

diff --git a/drivers/gpu/drm/nouveau/nouveau_display.c b/drivers/gpu/drm/nouveau/nouveau_display.c
index 7848590f5568..bdd5cf71a24c 100644
--- a/drivers/gpu/drm/nouveau/nouveau_display.c
+++ b/drivers/gpu/drm/nouveau/nouveau_display.c
@@ -50,7 +50,7 @@ nouveau_user_framebuffer_destroy(struct drm_framebuffer *drm_fb)
 	struct nouveau_framebuffer *fb = nouveau_framebuffer(drm_fb);
 
 	if (fb->nvbo)
-		drm_gem_object_unreference_unlocked(fb->nvbo->gem);
+		drm_gem_object_unreference_unlocked(&fb->nvbo->gem);
 
 	drm_framebuffer_cleanup(drm_fb);
 	kfree(fb);
@@ -63,7 +63,7 @@ nouveau_user_framebuffer_create_handle(struct drm_framebuffer *drm_fb,
 {
 	struct nouveau_framebuffer *fb = nouveau_framebuffer(drm_fb);
 
-	return drm_gem_handle_create(file_priv, fb->nvbo->gem, handle);
+	return drm_gem_handle_create(file_priv, &fb->nvbo->gem, handle);
 }
 
 static const struct drm_framebuffer_funcs nouveau_framebuffer_funcs = {
@@ -674,8 +674,8 @@ nouveau_display_dumb_create(struct drm_file *file_priv, struct drm_device *dev,
 	if (ret)
 		return ret;
 
-	ret = drm_gem_handle_create(file_priv, bo->gem, &args->handle);
-	drm_gem_object_unreference_unlocked(bo->gem);
+	ret = drm_gem_handle_create(file_priv, &bo->gem, &args->handle);
+	drm_gem_object_unreference_unlocked(&bo->gem);
 	return ret;
 }
 
@@ -688,7 +688,7 @@ nouveau_display_dumb_map_offset(struct drm_file *file_priv,
 
 	gem = drm_gem_object_lookup(dev, file_priv, handle);
 	if (gem) {
-		struct nouveau_bo *bo = gem->driver_private;
+		struct nouveau_bo *bo = nouveau_gem_object(gem);
 		*poffset = drm_vma_node_offset_addr(&bo->bo.vma_node);
 		drm_gem_object_unreference_unlocked(gem);
 		return 0;