diff --git a/include/linux/cgroup-defs.h b/include/linux/cgroup-defs.h
index 7d83d7f73420944fab444c842727a4b6f8fea7c7..26d1cea7929f1da98d1f80d4aa94fea9f6bf3c4b 100644
--- a/include/linux/cgroup-defs.h
+++ b/include/linux/cgroup-defs.h
@@ -26,6 +26,7 @@ struct cgroup_taskset;
 struct kernfs_node;
 struct kernfs_ops;
 struct kernfs_open_file;
+struct seq_file;
 
 #define MAX_CGROUP_TYPE_NAMELEN 32
 #define MAX_CGROUP_ROOT_NAMELEN 64