tracing/stat: Add stat_release() callback

Add stat_release() callback to struct tracer_stat, so a stat tracer
can release it's entries after the stat file has been read out.

Signed-off-by: Lai Jiangshan <laijs@cn.fujitsu.com>
Signed-off-by: Li Zefan <lizf@cn.fujitsu.com>
Cc: Lai Jiangshan <laijs@cn.fujitsu.com>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
LKML-Reference: <4A51B16A.6020708@cn.fujitsu.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>

2 files changed, 7 insertions, 2 deletions

diff --git a/kernel/trace/trace_stat.c b/kernel/trace/trace_stat.c
index e66f5e493342..f069461f10bd 100644
--- a/kernel/trace/trace_stat.c
+++ b/kernel/trace/trace_stat.c
@@ -49,7 +49,8 @@ static struct dentry		*stat_dir;
  * but it will at least advance closer to the next one
  * to be released.
  */
-static struct rb_node *release_next(struct rb_node *node)
+static struct rb_node *release_next(struct tracer_stat *ts,
+                                    struct rb_node *node)
 {
         struct stat_node *snode;
         struct rb_node *parent = rb_parent(node);
@@ -67,6 +68,8 @@ static struct rb_node *release_next(struct rb_node *node)
                         parent->rb_right = NULL;
 
                 snode = container_of(node, struct stat_node, node);
+                if (ts->stat_release)
+                        ts->stat_release(snode->stat);
                 kfree(snode);
 
                 return parent;
@@ -78,7 +81,7 @@ static void reset_stat_session(struct stat_session *session)
         struct rb_node *node = session->stat_root.rb_node;
 
         while (node)
-                node = release_next(node);
+                node = release_next(session->ts, node);
 
         session->stat_root = RB_ROOT;
 }
diff --git a/kernel/trace/trace_stat.h b/kernel/trace/trace_stat.h
index f3546a2cd826..8f03914b9a6a 100644
--- a/kernel/trace/trace_stat.h
+++ b/kernel/trace/trace_stat.h
@@ -18,6 +18,8 @@ struct tracer_stat {
         int                     (*stat_cmp)(void *p1, void *p2);
         /* Print a stat entry */
         int                     (*stat_show)(struct seq_file *s, void *p);
+        /* Release an entry */
+        void                    (*stat_release)(void *stat);
         /* Print the headers of your stat entries */
         int                     (*stat_headers)(struct seq_file *s);
 };