drm/mm: optimize find_hole() as well

Abort early if there isn't enough space to allocate from a subtree.
Signed-off-by: Christian König <christian.koenig@amd.com>
Acked-by: Nirmoy Das <nirmoy.das@amd.com>
Link: https://patchwork.freedesktop.org/patch/370297/

drivers/gpu/drm/drm_mm.c

@@ -325,7 +325,7 @@ static struct drm_mm_node *best_hole(struct drm_mm *mm, u64 size)
 	return best;
 }
 
-static struct drm_mm_node *find_hole(struct drm_mm *mm, u64 addr)
+static struct drm_mm_node *find_hole_addr(struct drm_mm *mm, u64 addr, u64 size)
 {
 	struct rb_node *rb = mm->holes_addr.rb_node;
 	struct drm_mm_node *node = NULL;
@@ -333,6 +333,9 @@ static struct drm_mm_node *find_hole(struct drm_mm *mm, u64 addr)
 	while (rb) {
 		u64 hole_start;
 
+		if (rb_hole_addr_to_node(rb)->subtree_max_hole < size)
+			break;
+
 		node = rb_hole_addr_to_node(rb);
 		hole_start = __drm_mm_hole_node_start(node);
 
@@ -358,10 +361,10 @@ first_hole(struct drm_mm *mm,
 		return best_hole(mm, size);
 
 	case DRM_MM_INSERT_LOW:
-		return find_hole(mm, start);
+		return find_hole_addr(mm, start, size);
 
 	case DRM_MM_INSERT_HIGH:
-		return find_hole(mm, end);
+		return find_hole_addr(mm, end, size);
 
 	case DRM_MM_INSERT_EVICT:
 		return list_first_entry_or_null(&mm->hole_stack,
@@ -497,7 +500,7 @@ int drm_mm_reserve_node(struct drm_mm *mm, struct drm_mm_node *node)
 		return -ENOSPC;
 
 	/* Find the relevant hole to add our node to */
-	hole = find_hole(mm, node->start);
+	hole = find_hole_addr(mm, node->start, 0);
 	if (!hole)
 		return -ENOSPC;
 

drivers/gpu/drm/selftests/test-drm_mm.c

@@ -1981,16 +1981,6 @@ static int __igt_once(unsigned int mode)
 	}
 
 	memset(&node, 0, sizeof(node));
-	err = drm_mm_insert_node_generic(&mm, &node,
-					 2, 0, 0,
-					 mode | DRM_MM_INSERT_ONCE);
-	if (!err) {
-		pr_err("Unexpectedly inserted the node into the wrong hole: node.start=%llx\n",
-		       node.start);
-		err = -EINVAL;
-		goto err_node;
-	}
-
 	err = drm_mm_insert_node_generic(&mm, &node, 2, 0, 0, mode);
 	if (err) {
 		pr_err("Could not insert the node into the available hole!\n");
@@ -1998,7 +1988,6 @@ static int __igt_once(unsigned int mode)
 		goto err_hi;
 	}
 
-err_node:
 	drm_mm_remove_node(&node);
 err_hi:
 	drm_mm_remove_node(&rsvd_hi);