diff --git a/block/blk-cgroup.c b/block/blk-cgroup.c
index a28ce591b28e..1f384b869c12 100644
--- a/block/blk-cgroup.c
+++ b/block/blk-cgroup.c
@@ -44,6 +44,7 @@ struct blkcg blkcg_root;
 EXPORT_SYMBOL_GPL(blkcg_root);
 
 struct cgroup_subsys_state * const blkcg_root_css = &blkcg_root.css;
+EXPORT_SYMBOL_GPL(blkcg_root_css);
 
 static struct blkcg_policy *blkcg_policy[BLKCG_MAX_POLS];
 
diff --git a/fs/fs-writeback.c b/fs/fs-writeback.c
index 1014659a19af..d16e02891818 100644
--- a/fs/fs-writeback.c
+++ b/fs/fs-writeback.c
@@ -598,6 +598,7 @@ void wbc_attach_and_unlock_inode(struct writeback_control *wbc,
 	if (unlikely(wb_dying(wbc->wb) && !css_is_dying(wbc->wb->memcg_css)))
 		inode_switch_wbs(inode, wbc->wb_id);
 }
+EXPORT_SYMBOL_GPL(wbc_attach_and_unlock_inode);
 
 /**
  * wbc_detach_inode - disassociate wbc from inode and perform foreign detection
@@ -717,6 +718,7 @@ void wbc_detach_inode(struct writeback_control *wbc)
 	wb_put(wbc->wb);
 	wbc->wb = NULL;
 }
+EXPORT_SYMBOL_GPL(wbc_detach_inode);
 
 /**
  * wbc_account_io - account IO issued during writeback
diff --git a/include/linux/cgroup.h b/include/linux/cgroup.h
index 341d68bc8b5a..1bdca7235342 100755
--- a/include/linux/cgroup.h
+++ b/include/linux/cgroup.h
@@ -704,6 +704,7 @@ void cgroup_path_from_kernfs_id(u64 id, char *buf, size_t buflen);
 struct cgroup_subsys_state;
 struct cgroup;
 
+static inline void css_get(struct cgroup_subsys_state *css) {}
 static inline void css_put(struct cgroup_subsys_state *css) {}
 static inline int cgroup_attach_task_all(struct task_struct *from,
 					 struct task_struct *t) { return 0; }