From: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
Date: Wed, 21 Dec 2011 13:53:48 +0000 (-0500)
Subject: cds_lfht_replace: add checks for old/new node hash/value match
X-Git-Tag: v0.7.0~43^2~7
X-Git-Url: https://git.lttng.org./?a=commitdiff_plain;h=2e79c44597547799d9501940b660f676a559b738;p=userspace-rcu.git

cds_lfht_replace: add checks for old/new node hash/value match

Also initialize reverse hash in replace.

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

diff --git a/rculfhash.c b/rculfhash.c
index 75e5ece..1eda2dd 100644
--- a/rculfhash.c
+++ b/rculfhash.c
@@ -1517,11 +1517,22 @@ struct cds_lfht_node *cds_lfht_add_replace(struct cds_lfht *ht,
 	}
 }
 
-int cds_lfht_replace(struct cds_lfht *ht, struct cds_lfht_iter *old_iter,
+int cds_lfht_replace(struct cds_lfht *ht,
+		struct cds_lfht_iter *old_iter,
+		unsigned long hash,
+		cds_lfht_match_fct match,
+		const void *key,
 		struct cds_lfht_node *new_node)
 {
 	unsigned long size;
 
+	new_node->reverse_hash = bit_reverse_ulong((unsigned long) hash);
+	if (!old_iter->node)
+		return -ENOENT;
+	if (caa_unlikely(old_iter->node->reverse_hash != new_node->reverse_hash))
+		return -EINVAL;
+	if (caa_unlikely(!match(old_iter->node, key)))
+		return -EINVAL;
 	size = rcu_dereference(ht->size);
 	return _cds_lfht_replace(ht, size, old_iter->node, old_iter->next,
 			new_node);
diff --git a/urcu/rculfhash.h b/urcu/rculfhash.h
index b33ede0..96dc5a0 100644
--- a/urcu/rculfhash.h
+++ b/urcu/rculfhash.h
@@ -325,11 +325,16 @@ struct cds_lfht_node *cds_lfht_add_replace(struct cds_lfht *ht,
  * cds_lfht_replace - replace a node pointer to by iter within hash table.
  * @ht: the hash table.
  * @old_iter: the iterator position of the node to replace.
- * @now_node: the new node to try using for replacement.
+ * @hash: the node's hash.
+ * @match: the key match function.
+ * @key: the node's key.
+ * @new_node: the new node to use as replacement.
  *
  * Return 0 if replacement is successful, negative value otherwise.
- * Replacing a NULL old node or an already removed node will fail with a
- * negative value.
+ * Replacing a NULL old node or an already removed node will fail with
+ * -ENOENT.
+ * If the hash or value of the node to replace and the new node differ,
+ * this function returns -EINVAL without proceeding to the replacement.
  * Old node can be looked up with cds_lfht_lookup and cds_lfht_next.
  * RCU read-side lock must be held between lookup and replacement.
  * Call with rcu_read_lock held.
@@ -348,7 +353,11 @@ struct cds_lfht_node *cds_lfht_add_replace(struct cds_lfht *ht,
  * guarantee that a combination of add_replace and add_unique updates
  * will never generate duplicated keys.
  */
-int cds_lfht_replace(struct cds_lfht *ht, struct cds_lfht_iter *old_iter,
+int cds_lfht_replace(struct cds_lfht *ht,
+		struct cds_lfht_iter *old_iter,
+		unsigned long hash,
+		cds_lfht_match_fct match,
+		const void *key,
 		struct cds_lfht_node *new_node);
 
 /*