list_for_each_rcu - iterate over an rcu-protected list
list_for_each_rcu (pos, head);
pos the &struct list_head to use as a loop counter. head the head for your list.
This list-traversal primitive may safely run concurrently with the _rcu list-mutation primitives such as list_add_rcu as long as the traversal is guarded by rcu_read_lock.