extern void cds_lfs_push_rcu(struct cds_lfs_stack_rcu *s, struct cds_lfs_node_rcu *node);
/*
+ * Should be called under rcu read lock critical section.
+ *
* The caller must wait for a grace period to pass before freeing the returned
* node or modifying the cds_lfs_node_rcu structure.
* Returns NULL if stack is empty.