hlist: implement cds_hlist_first_entry_rcu

Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>

diff --git a/urcu/rcuhlist.h b/urcu/rcuhlist.h
index 8549550e7fab3358fd031b30ed87ff67244f1472..4635593b4cb00449dd1fe82ebc70e70da3743cef 100644 (file)
--- a/urcu/rcuhlist.h
+++ b/urcu/rcuhlist.h
@@ -50,6 +50,12 @@ static inline void cds_hlist_del_rcu(struct cds_hlist_node *elem)
        elem->prev->next = elem->next;
 }
 
+/*
+ * Get first entry from a RCU hlist. Assumes the hlist is not empty.
+ * This must be done while rcu_read_lock() is held.
+ */
+#define cds_hlist_first_entry_rcu(ptr, type, member) \
+       cds_hlist_entry(rcu_dereference((ptr)->next), type, member)
 
 /* Iterate through elements of the list.
  * This must be done while rcu_read_lock() is held.