list_add_rcu — add a new entry to rcu-protected list
void list_add_rcu (struct list_head * new, struct list_head * head);
Insert a new entry after the specified head. This is good for implementing stacks.
The caller must take whatever precautions are necessary
(such as holding appropriate locks) to avoid racing
with another list-mutation primitive, such as list_add_rcu
or list_del_rcu, running on this same list.
However, it is perfectly legal to run concurrently with
the _rcu list-traversal primitives, such as
list_for_each_entry_rcu.