From: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
Date: Wed, 21 Dec 2011 13:24:25 +0000 (-0500)
Subject: rculfhash: use node instead of iter argument for deletion
X-Git-Tag: v0.7.0~43^2~8
X-Git-Url: https://git.lttng.org./?a=commitdiff_plain;h=bc8c3c74b84e838b195faa8871344f5b672ae1cd;p=userspace-rcu.git

rculfhash: use node instead of iter argument for deletion

Using a node instead of an iterator as argument for deletion allows
passing a node pointer (that would have been looked up from another data
structure, thus not using the iterator) as argument for deletion.

Deletion still returns -ENOENT if asked to delete the NULL node. This
simplifies the caller usage.

Suggested-by: Lai Jiangshan <laijs@cn.fujitsu.com>
Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
---

diff --git a/rculfhash.c b/rculfhash.c
index f214293..75e5ece 100644
--- a/rculfhash.c
+++ b/rculfhash.c
@@ -1527,15 +1527,15 @@ int cds_lfht_replace(struct cds_lfht *ht, struct cds_lfht_iter *old_iter,
 			new_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)
 {
 	unsigned long size, hash;
 	int ret;
 
 	size = rcu_dereference(ht->size);
-	ret = _cds_lfht_del(ht, size, iter->node);
+	ret = _cds_lfht_del(ht, size, node);
 	if (!ret) {
-		hash = bit_reverse_ulong(iter->node->reverse_hash);
+		hash = bit_reverse_ulong(node->reverse_hash);
 		ht_count_del(ht, size, hash);
 	}
 	return ret;
diff --git a/tests/test_urcu_hash.c b/tests/test_urcu_hash.c
index 8c6f0da..eb6cca9 100644
--- a/tests/test_urcu_hash.c
+++ b/tests/test_urcu_hash.c
@@ -610,7 +610,7 @@ void *thr_writer(void *_count)
 			cds_lfht_test_lookup(test_ht,
 				(void *)(((unsigned long) rand_r(&rand_lookup) % write_pool_size) + write_pool_offset),
 				sizeof(void *), &iter);
-			ret = cds_lfht_del(test_ht, &iter);
+			ret = cds_lfht_del(test_ht, cds_lfht_iter_get_node(&iter));
 			rcu_read_unlock();
 			if (ret == 0) {
 				node = cds_lfht_iter_get_test_node(&iter);
@@ -715,7 +715,7 @@ void test_delete_all_nodes(struct cds_lfht *ht)
 	cds_lfht_for_each_entry(ht, &iter, node, node) {
 		int ret;
 
-		ret = cds_lfht_del(test_ht, &iter);
+		ret = cds_lfht_del(test_ht, cds_lfht_iter_get_node(&iter));
 		assert(!ret);
 		call_rcu(&node->head, free_node_cb);
 		count++;
diff --git a/urcu/rculfhash.h b/urcu/rculfhash.h
index 6ea00de..b33ede0 100644
--- a/urcu/rculfhash.h
+++ b/urcu/rculfhash.h
@@ -354,14 +354,14 @@ int cds_lfht_replace(struct cds_lfht *ht, struct cds_lfht_iter *old_iter,
 /*
  * 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.
@@ -369,7 +369,7 @@ 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_resize - Force a hash table resize