rculfhash: update comments in implementation

[urcu.git] / urcu / rculfhash.h

diff --git a/urcu/rculfhash.h b/urcu/rculfhash.h
index de34fae0b424b20a0b7d7538932376209a603969..004c20817b8585e1cecc21f37068b8725b8a5d43 100644 (file)
--- a/urcu/rculfhash.h
+++ b/urcu/rculfhash.h
@@ -182,7 +182,6 @@ int cds_lfht_destroy(struct cds_lfht *ht, pthread_attr_t **attr);
  * @ht: the hash table.
  * @split_count_before: Sample the node count split-counter before traversal.
  * @count: Traverse the hash table, count the number of nodes observed.
- * @removed: Number of logically removed nodes observed during traversal.
  * @split_count_after: Sample the node count split-counter after traversal.
  *
  * Call with rcu_read_lock held.
@@ -191,7 +190,6 @@ int cds_lfht_destroy(struct cds_lfht *ht, pthread_attr_t **attr);
 void cds_lfht_count_nodes(struct cds_lfht *ht,
                long *split_count_before,
                unsigned long *count,
-               unsigned long *removed,
                long *split_count_after);
 
 /*
@@ -216,7 +214,8 @@ void cds_lfht_lookup(struct cds_lfht *ht, unsigned long hash,
  * @key: the current node key.
  * @iter: Node, if found (output). *iter->node set to NULL if not found.
  *
- * Uses an iterator initialized by a lookup.
+ * Uses an iterator initialized by a lookup. Important: the iterator
+ * _needs_ to be initialized before calling cds_lfht_next_duplicate.
  * Sets *iter-node to the following node with same key.
  * Sets *iter->node to NULL if no following node exists with same key.
  * RCU read-side lock must be held across cds_lfht_lookup and
@@ -324,14 +323,19 @@ struct cds_lfht_node *cds_lfht_add_replace(struct cds_lfht *ht,
                struct cds_lfht_node *node);
 
 /*
- * cds_lfht_replace - replace a node pointer to by iter within hash table.
+ * cds_lfht_replace - replace a node pointed 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.
@@ -350,20 +354,24 @@ 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);
 
 /*
  * cds_lfht_del - remove node pointed to by iterator from hash table.
  * @ht: the hash table.
- * @iter: the iterator position of the node to delete.
+ * @node: the node to delete.
  *
  * Return 0 if the node is successfully removed, negative value
  * otherwise.
- * Replacing a NULL node or an already removed node will fail with a
+ * Deleting a NULL node or an already removed node will fail with a
  * negative value.
- * Node can be looked up with cds_lfht_lookup and cds_lfht_next.
- * cds_lfht_iter_get_node.
+ * Node can be looked up with cds_lfht_lookup and cds_lfht_next,
+ * followed by use of cds_lfht_iter_get_node.
  * RCU read-side lock must be held between lookup and removal.
  * Call with rcu_read_lock held.
  * Threads calling this API need to be registered RCU read-side threads.
@@ -371,7 +379,21 @@ int cds_lfht_replace(struct cds_lfht *ht, struct cds_lfht_iter *old_iter,
  * freeing the memory reserved for old node (which can be accessed with
  * cds_lfht_iter_get_node).
  */
-int cds_lfht_del(struct cds_lfht *ht, struct cds_lfht_iter *iter);
+int cds_lfht_del(struct cds_lfht *ht, struct cds_lfht_node *node);
+
+/*
+ * cds_lfht_is_node_deleted - query if a node is removed from hash table.
+ *
+ * Return non-zero if the node is deleted from the hash table, 0
+ * otherwise.
+ * Node can be looked up with cds_lfht_lookup and cds_lfht_next,
+ * followed by use of cds_lfht_iter_get_node.
+ * RCU read-side lock must be held between lookup and call to this
+ * function.
+ * Call with rcu_read_lock held.
+ * Threads calling this API need to be registered RCU read-side threads.
+ */
+int cds_lfht_is_node_deleted(struct cds_lfht_node *node);
 
 /*
  * cds_lfht_resize - Force a hash table resize