diff --git a/include/net/tcp_memcontrol.h b/include/net/tcp_memcontrol.h
index 3a17b16ae8aa47c4cb3f242291533d9be86fcd75..01ff7c6efada979784bd2ac888e3e24e19a511ed 100644
--- a/include/net/tcp_memcontrol.h
+++ b/include/net/tcp_memcontrol.h
@@ -1,6 +1,9 @@
 #ifndef _TCP_MEMCG_H
 #define _TCP_MEMCG_H
 
+struct cgroup_subsys;
+struct mem_cgroup;
+
 int tcp_init_cgroup(struct mem_cgroup *memcg, struct cgroup_subsys *ss);
 void tcp_destroy_cgroup(struct mem_cgroup *memcg);
 #endif /* _TCP_MEMCG_H */