[ltt-dev] [PATCH 3/9] add cds_lfht_add_at()

[Lai Jiangshan]

Signed-off-by: Lai Jiangshan <laijs at cn.fujitsu.com>
---
 rculfhash.c      |   24 +++++++++++++++++++++++-
 urcu/rculfhash.h |   14 ++++++++++++++
 2 files changed, 37 insertions(+), 1 deletions(-)

diff --git a/rculfhash.c b/rculfhash.c
index cbfc79e..70f5863 100644
--- a/rculfhash.c
+++ b/rculfhash.c
@@ -1495,12 +1495,34 @@ void cds_lfht_add(struct cds_lfht *ht, unsigned long hash,
 {
 	unsigned long size;
 
-	node->reverse_hash = bit_reverse_ulong((unsigned long) hash);
+	node->reverse_hash = bit_reverse_ulong(hash);
 	size = rcu_dereference(ht->t.size);
 	_cds_lfht_add(ht, NULL, NULL, size, node, NULL, 0);
 	ht_count_add(ht, size, hash);
 }
 
+bool cds_lfht_add_at(struct cds_lfht *ht, struct cds_lfht_iter *iter,
+		unsigned long hash, struct cds_lfht_node *node)
+{
+	struct cds_lfht_node *new_node;
+
+	if (caa_unlikely(is_removed(iter->next)))
+		return false;
+
+	node->reverse_hash = bit_reverse_ulong(hash);
+	node->next = clear_flag(iter->next);
+	if (is_bucket(iter->next))
+		new_node = flag_bucket(node);
+	else
+		new_node = node;
+	if (uatomic_cmpxchg(&iter->node->next, iter->next,
+			new_node) != iter->next)
+		return false;
+
+	ht_count_add(ht, rcu_dereference(ht->t.size), hash);
+	return true;
+}
+
 struct cds_lfht_node *cds_lfht_add_unique(struct cds_lfht *ht,
 				unsigned long hash,
 				cds_lfht_match_fct match,
diff --git a/urcu/rculfhash.h b/urcu/rculfhash.h
index 7d919d0..0f9bf44 100644
--- a/urcu/rculfhash.h
+++ b/urcu/rculfhash.h
@@ -250,6 +250,20 @@ void cds_lfht_add(struct cds_lfht *ht, unsigned long hash,
 		struct cds_lfht_node *node);
 
 /*
+ * cds_lfht_add_at - add a node to the hash table at the specified place.
+ * @ht: the hash table.
+ * @iter: the specified place to insert
+ * @hash: the key hash.
+ * @node: the node to add.
+ *
+ * This function supports adding redundant keys into the table.
+ * Call with rcu_read_lock held.
+ * Threads calling this API need to be registered RCU read-side threads.
+ */
+bool cds_lfht_add_at(struct cds_lfht *ht, struct cds_lfht_iter *iter,
+		unsigned long hash, struct cds_lfht_node *node);
+
+/*
  * cds_lfht_add_unique - add a node to hash table, if key is not present.
  * @ht: the hash table.
  * @hash: the node's hash.
-- 
1.7.4.4