Start an iteration of a hlist protected by rcu
struct hlist_node * seq_hlist_start_rcu(struct hlist_head * head, loff_t pos);
head
the head of the hlist
pos
the start position of the sequence
Called at seq_file->op->start.
This list-traversal primitive may safely run concurrently with the _rcu list-mutation primitives such as hlist_add_head_rcu as long as the traversal is guarded by rcu_read_lock.