return __is_page_sharing_candidate(stable_node, 0);
 }
 
-struct page *stable_node_dup(struct stable_node **_stable_node_dup,
-                            struct stable_node **_stable_node,
-                            struct rb_root *root,
-                            bool prune_stale_stable_nodes)
+static struct page *stable_node_dup(struct stable_node **_stable_node_dup,
+                                   struct stable_node **_stable_node,
+                                   struct rb_root *root,
+                                   bool prune_stale_stable_nodes)
 {
        struct stable_node *dup, *found = NULL, *stable_node = *_stable_node;
        struct hlist_node *hlist_safe;