drm/i915: Embed drm_mm_node in i915 gem obj

Embedding the node in the obj is more natural in the transition to VMAs
which will also have embedded nodes. This change also helps transition
away from put_block to remove node.

Though it's quite an uncommon occurrence, it's somewhat convenient to not
fail at bind time because we cannot allocate the node. Though in
practice there are other allocations (like the request structure) which
would probably make this point not terribly useful.

Quoting Daniel:
Note that the only difference between put_block and remove_node is
that the former fills up the preallocation cache. Which we don't need
anyway and hence is just wasted space.

v2: Clean up the stolen preallocation code.
Rebased on the reserve_node patches
renames ggtt_ stuff to gtt_ stuff
WARN_ON if the object is already bound (which doesn't mean it's in the
bound list, tricky)

Signed-off-by: Ben Widawsky <ben@bwidawsk.net>
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>

drivers/gpu/drm/i915/i915_drv.h

@@ -1201,7 +1201,6 @@ enum hdmi_force_audio {
 	HDMI_AUDIO_ON,			/* force turn on HDMI audio */
 };
 
-#define I915_GTT_RESERVED (1<<0)
 #define I915_GTT_OFFSET_NONE ((u32)-1)
 
 struct drm_i915_gem_object_ops {
@@ -1228,7 +1227,7 @@ struct drm_i915_gem_object {
 	const struct drm_i915_gem_object_ops *ops;
 
 	/** Current space allocated to this object in the GTT, if any. */
-	struct drm_mm_node *gtt_space;
+	struct drm_mm_node gtt_space;
 	/** Stolen memory for this object, instead of being backed by shmem. */
 	struct drm_mm_node *stolen;
 	struct list_head global_list;
@@ -1358,14 +1357,14 @@ struct drm_i915_gem_object {
 static inline unsigned long
 i915_gem_obj_ggtt_offset(struct drm_i915_gem_object *o)
 {
-	return o->gtt_space->start;
+	return o->gtt_space.start;
 }
 
 /* Whether or not this object is currently mapped by the translation tables */
 static inline bool
 i915_gem_obj_ggtt_bound(struct drm_i915_gem_object *o)
 {
-	return o->gtt_space != NULL;
+	return drm_mm_node_allocated(&o->gtt_space);
 }
 
 /* The size used in the translation tables may be larger than the actual size of
@@ -1375,14 +1374,14 @@ i915_gem_obj_ggtt_bound(struct drm_i915_gem_object *o)
 static inline unsigned long
 i915_gem_obj_ggtt_size(struct drm_i915_gem_object *o)
 {
-	return o->gtt_space->size;
+	return o->gtt_space.size;
 }
 
 static inline void
 i915_gem_obj_ggtt_set_color(struct drm_i915_gem_object *o,
 			    enum i915_cache_level color)
 {
-	o->gtt_space->color = color;
+	o->gtt_space.color = color;
 }
 
 /**

drivers/gpu/drm/i915/i915_gem.c

@@ -2632,8 +2632,7 @@ i915_gem_object_unbind(struct drm_i915_gem_object *obj)
 	/* Avoid an unnecessary call to unbind on rebind. */
 	obj->map_and_fenceable = true;
 
-	drm_mm_put_block(obj->gtt_space);
-	obj->gtt_space = NULL;
+	drm_mm_remove_node(&obj->gtt_space);
 
 	return 0;
 }
@@ -3011,7 +3010,7 @@ static bool i915_gem_valid_gtt_space(struct drm_device *dev,
 	if (HAS_LLC(dev))
 		return true;
 
-	if (gtt_space == NULL)
+	if (!drm_mm_node_allocated(gtt_space))
 		return true;
 
 	if (list_empty(&gtt_space->node_list))
@@ -3079,7 +3078,6 @@ i915_gem_object_bind_to_gtt(struct drm_i915_gem_object *obj,
 {
 	struct drm_device *dev = obj->base.dev;
 	drm_i915_private_t *dev_priv = dev->dev_private;
-	struct drm_mm_node *node;
 	u32 size, fence_size, fence_alignment, unfenced_alignment;
 	bool mappable, fenceable;
 	size_t gtt_max = map_and_fenceable ?
@@ -3124,14 +3122,9 @@ i915_gem_object_bind_to_gtt(struct drm_i915_gem_object *obj,
 
 	i915_gem_object_pin_pages(obj);
 
-	node = kzalloc(sizeof(*node), GFP_KERNEL);
-	if (node == NULL) {
-		i915_gem_object_unpin_pages(obj);
-		return -ENOMEM;
-	}
-
 search_free:
-	ret = drm_mm_insert_node_in_range_generic(&dev_priv->mm.gtt_space, node,
+	ret = drm_mm_insert_node_in_range_generic(&dev_priv->mm.gtt_space,
+						  &obj->gtt_space,
 						  size, alignment,
 						  obj->cache_level, 0, gtt_max);
 	if (ret) {
@@ -3143,30 +3136,28 @@ search_free:
 			goto search_free;
 
 		i915_gem_object_unpin_pages(obj);
-		kfree(node);
 		return ret;
 	}
-	if (WARN_ON(!i915_gem_valid_gtt_space(dev, node, obj->cache_level))) {
+	if (WARN_ON(!i915_gem_valid_gtt_space(dev, &obj->gtt_space,
+					      obj->cache_level))) {
 		i915_gem_object_unpin_pages(obj);
-		drm_mm_put_block(node);
+		drm_mm_remove_node(&obj->gtt_space);
 		return -EINVAL;
 	}
 
 	ret = i915_gem_gtt_prepare_object(obj);
 	if (ret) {
 		i915_gem_object_unpin_pages(obj);
-		drm_mm_put_block(node);
+		drm_mm_remove_node(&obj->gtt_space);
 		return ret;
 	}
 
 	list_move_tail(&obj->global_list, &dev_priv->mm.bound_list);
 	list_add_tail(&obj->mm_list, &dev_priv->mm.inactive_list);
 
-	obj->gtt_space = node;
-
 	fenceable =
-		node->size == fence_size &&
-		(node->start & (fence_alignment - 1)) == 0;
+		i915_gem_obj_ggtt_size(obj) == fence_size &&
+		(i915_gem_obj_ggtt_offset(obj) & (fence_alignment - 1)) == 0;
 
 	mappable = i915_gem_obj_ggtt_offset(obj) + obj->base.size <=
 		dev_priv->gtt.mappable_end;
@@ -3330,7 +3321,7 @@ int i915_gem_object_set_cache_level(struct drm_i915_gem_object *obj,
 		return -EBUSY;
 	}
 
-	if (!i915_gem_valid_gtt_space(dev, obj->gtt_space, cache_level)) {
+	if (!i915_gem_valid_gtt_space(dev, &obj->gtt_space, cache_level)) {
 		ret = i915_gem_object_unbind(obj);
 		if (ret)
 			return ret;

drivers/gpu/drm/i915/i915_gem_evict.c

@@ -38,7 +38,7 @@ mark_free(struct drm_i915_gem_object *obj, struct list_head *unwind)
 		return false;
 
 	list_add(&obj->exec_list, unwind);
-	return drm_mm_scan_add_block(obj->gtt_space);
+	return drm_mm_scan_add_block(&obj->gtt_space);
 }
 
 int
@@ -107,7 +107,7 @@ none:
 				       struct drm_i915_gem_object,
 				       exec_list);
 
-		ret = drm_mm_scan_remove_block(obj->gtt_space);
+		ret = drm_mm_scan_remove_block(&obj->gtt_space);
 		BUG_ON(ret);
 
 		list_del_init(&obj->exec_list);
@@ -127,7 +127,7 @@ found:
 		obj = list_first_entry(&unwind_list,
 				       struct drm_i915_gem_object,
 				       exec_list);
-		if (drm_mm_scan_remove_block(obj->gtt_space)) {
+		if (drm_mm_scan_remove_block(&obj->gtt_space)) {
 			list_move(&obj->exec_list, &eviction_list);
 			drm_gem_object_reference(&obj->base);
 			continue;

drivers/gpu/drm/i915/i915_gem_gtt.c

@@ -629,28 +629,15 @@ void i915_gem_setup_global_gtt(struct drm_device *dev,
 
 	/* Mark any preallocated objects as occupied */
 	list_for_each_entry(obj, &dev_priv->mm.bound_list, global_list) {
-		uintptr_t offset = (uintptr_t) obj->gtt_space;
 		int ret;
 		DRM_DEBUG_KMS("reserving preallocated space: %lx + %zx\n",
-			      offset, obj->base.size);
-
-		BUG_ON((offset & I915_GTT_RESERVED) != 0);
-		offset &= ~I915_GTT_RESERVED;
-		obj->gtt_space = kzalloc(sizeof(*obj->gtt_space), GFP_KERNEL);
-		if (!obj->gtt_space) {
-			DRM_ERROR("Failed to preserve object at offset %lx\n",
-				  offset);
-			continue;
-		}
-		obj->gtt_space->start = (unsigned long)offset;
-		obj->gtt_space->size = obj->base.size;
+			      i915_gem_obj_ggtt_offset(obj), obj->base.size);
+
+		WARN_ON(i915_gem_obj_ggtt_bound(obj));
 		ret = drm_mm_reserve_node(&dev_priv->mm.gtt_space,
-					  obj->gtt_space);
-		if (ret) {
+					  &obj->gtt_space);
+		if (ret)
 			DRM_DEBUG_KMS("Reservation failed\n");
-			kfree(obj->gtt_space);
-			obj->gtt_space = NULL;
-		}
 		obj->has_global_gtt_mapping = 1;
 	}
 

drivers/gpu/drm/i915/i915_gem_stolen.c

@@ -374,26 +374,15 @@ i915_gem_object_create_stolen_for_preallocated(struct drm_device *dev,
 	 * setting up the GTT space. The actual reservation will occur
 	 * later.
 	 */
+	obj->gtt_space.start = gtt_offset;
+	obj->gtt_space.size = size;
 	if (drm_mm_initialized(&dev_priv->mm.gtt_space)) {
-		obj->gtt_space = kzalloc(sizeof(*obj->gtt_space), GFP_KERNEL);
-		if (!obj->gtt_space) {
-			DRM_DEBUG_KMS("-ENOMEM stolen GTT space\n");
-			goto unref_out;
-		}
-
-		obj->gtt_space->start = gtt_offset;
-		obj->gtt_space->size = size;
 		ret = drm_mm_reserve_node(&dev_priv->mm.gtt_space,
-					  obj->gtt_space);
+					  &obj->gtt_space);
 		if (ret) {
 			DRM_DEBUG_KMS("failed to allocate stolen GTT space\n");
-			goto free_out;
+			goto unref_out;
 		}
-	} else {
-		if (WARN_ON(gtt_offset & ~PAGE_MASK))
-			DRM_DEBUG_KMS("Cannot preserve non page aligned offset\n");
-		obj->gtt_space =
-			(struct drm_mm_node *)((uintptr_t)(I915_GTT_RESERVED | gtt_offset));
 	}
 
 	obj->has_global_gtt_mapping = 1;
@@ -403,9 +392,6 @@ i915_gem_object_create_stolen_for_preallocated(struct drm_device *dev,
 
 	return obj;
 
-free_out:
-	kfree(obj->gtt_space);
-	obj->gtt_space = NULL;
 unref_out:
 	drm_gem_object_unreference(&obj->base);
 	return NULL;