From: Rusty Russell <rusty@rustcorp.com.au>
Date: Mon, 10 Jan 2011 05:17:24 +0000 (+1030)
Subject: rbtree: don't use temporary context to destroy rbtree
X-Git-Url: http://git.ozlabs.org/?p=ccan;a=commitdiff_plain;h=7467dfe718aa1de8eba6fb16d2eb8b5b2248e017

rbtree: don't use temporary context to destroy rbtree

It leads to a memory leak if the allocation fails (as we reparent onto NULL).
Also, the extra allocation in the failure path increases test time for
failtest (under valgrind) by a factor of 2.
---

diff --git a/ccan/rbtree/rbtree.c b/ccan/rbtree/rbtree.c
index 753935b3..e3b4a951 100644
--- a/ccan/rbtree/rbtree.c
+++ b/ccan/rbtree/rbtree.c
@@ -19,16 +19,16 @@
 #include <ccan/rbtree/rbtree.h>
 
 static void
-tree_destructor_traverse_node(TALLOC_CTX *mem_ctx, trbt_node_t *node)
+tree_destructor_traverse_node(trbt_node_t *node)
 {
 	talloc_set_destructor(node, NULL);
 	if (node->left) {
-		tree_destructor_traverse_node(mem_ctx, node->left);
+		tree_destructor_traverse_node(node->left);
 	}
 	if (node->right) {
-		tree_destructor_traverse_node(mem_ctx, node->right);
+		tree_destructor_traverse_node(node->right);
 	}
-	talloc_steal(mem_ctx, node);
+	talloc_free(node);
 }
 
 /*
@@ -36,7 +36,6 @@ tree_destructor_traverse_node(TALLOC_CTX *mem_ctx, trbt_node_t *node)
  */
 static int tree_destructor(trbt_tree_t *tree)
 {
-	TALLOC_CTX *tmp_ctx;
 	trbt_node_t *node;
 
 	if (tree == NULL) {
@@ -48,17 +47,14 @@ static int tree_destructor(trbt_tree_t *tree)
 		return 0;
 	}
 
-	/* traverse the tree and remove the node destructor and steal
-	   the node to the temporary context.
+	/* traverse the tree and remove the node destructor then delete it.
 	   we dont want to use the existing destructor for the node
 	   since that will remove the nodes one by one from the tree.
 	   since the entire tree will be completely destroyed we dont care
 	   if it is inconsistent or unbalanced while freeing the
 	   individual nodes
 	*/
-	tmp_ctx = talloc_new(NULL);
-	tree_destructor_traverse_node(tmp_ctx, node);
-	talloc_free(tmp_ctx);
+	tree_destructor_traverse_node(node);
 
 	return 0;
 }