trace/trace_stat: use rbtree postorder iteration helper instead of opencoding

Use rbtree_postorder_for_each_entry_safe() to destroy the rbtree instead
of opencoding an alternate postorder iteration that modifies the tree

Link: http://lkml.kernel.org/r/1383345566-25087-2-git-send-email-cody@linux.vnet.ibm.com

Signed-off-by: Cody P Schafer <cody@linux.vnet.ibm.com>
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>

1 files changed, 5 insertions, 36 deletions

diff --git a/kernel/trace/trace_stat.c b/kernel/trace/trace_stat.c
index 847f88a6194b..7af67360b330 100644
--- a/kernel/trace/trace_stat.c
+++ b/kernel/trace/trace_stat.c
@@ -43,46 +43,15 @@ static DEFINE_MUTEX(all_stat_sessions_mutex);
 /* The root directory for all stat files */
 static struct dentry            *stat_dir;
 
-/*
- * Iterate through the rbtree using a post order traversal path
- * to release the next node.
- * It won't necessary release one at each iteration
- * but it will at least advance closer to the next one
- * to be released.
- */
-static struct rb_node *release_next(struct tracer_stat *ts,
-                                    struct rb_node *node)
+static void __reset_stat_session(struct stat_session *session)
 {
-        struct stat_node *snode;
-        struct rb_node *parent = rb_parent(node);
-
-        if (node->rb_left)
-                return node->rb_left;
-        else if (node->rb_right)
-                return node->rb_right;
-        else {
-                if (!parent)
-                        ;
-                else if (parent->rb_left == node)
-                        parent->rb_left = NULL;
-                else
-                        parent->rb_right = NULL;
+        struct stat_node *snode, *n;
 
-                snode = container_of(node, struct stat_node, node);
-                if (ts->stat_release)
-                        ts->stat_release(snode->stat);
+        rbtree_postorder_for_each_entry_safe(snode, n, &session->stat_root, node) {
+                if (session->ts->stat_release)
+                        session->ts->stat_release(snode->stat);
                 kfree(snode);
-
-                return parent;
         }
-}
-
-static void __reset_stat_session(struct stat_session *session)
-{
-        struct rb_node *node = session->stat_root.rb_node;
-
-        while (node)
-                node = release_next(session->ts, node);
 
         session->stat_root = RB_ROOT;
 }