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-rw-r--r--include/linux/rculist.h21
1 files changed, 21 insertions, 0 deletions
diff --git a/include/linux/rculist.h b/include/linux/rculist.h
index 8214cdc715f2..67867e0d4cec 100644
--- a/include/linux/rculist.h
+++ b/include/linux/rculist.h
@@ -506,6 +506,27 @@ static inline void hlist_replace_rcu(struct hlist_node *old,
WRITE_ONCE(old->pprev, LIST_POISON2);
}
+/**
+ * hlists_swap_heads_rcu - swap the lists the hlist heads point to
+ * @left: The hlist head on the left
+ * @right: The hlist head on the right
+ *
+ * The lists start out as [@left ][node1 ... ] and
+ [@right ][node2 ... ]
+ * The lists end up as [@left ][node2 ... ]
+ * [@right ][node1 ... ]
+ */
+static inline void hlists_swap_heads_rcu(struct hlist_head *left, struct hlist_head *right)
+{
+ struct hlist_node *node1 = left->first;
+ struct hlist_node *node2 = right->first;
+
+ rcu_assign_pointer(left->first, node2);
+ rcu_assign_pointer(right->first, node1);
+ WRITE_ONCE(node2->pprev, &left->first);
+ WRITE_ONCE(node1->pprev, &right->first);
+}
+
/*
* return the first or the next element in an RCU protected hlist
*/