tracing: add back the available_events file

The event directory files type and available_types were no longer
needed with the new TRACE_EVENT_FORMAT macros, they were deleted.
But by accident the available_events file was also removed.
This patch brings it back.

Reported-by: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>
Signed-off-by: Steven Rostedt <srostedt@redhat.com>

1 files changed, 14 insertions, 0 deletions

diff --git a/kernel/trace/trace_events.c b/kernel/trace/trace_events.c
index 85ec10fbb38d..769dfd00fc85 100644
--- a/kernel/trace/trace_events.c
+++ b/kernel/trace/trace_events.c
@@ -428,6 +428,13 @@ static const struct seq_operations show_set_event_seq_ops = {
         .stop = t_stop,
 };
 
+static const struct file_operations ftrace_avail_fops = {
+        .open = ftrace_event_seq_open,
+        .read = seq_read,
+        .llseek = seq_lseek,
+        .release = seq_release,
+};
+
 static const struct file_operations ftrace_set_event_fops = {
         .open = ftrace_event_seq_open,
         .read = seq_read,
@@ -569,6 +576,13 @@ static __init int event_trace_init(void)
         if (!d_tracer)
                 return 0;
 
+        entry = debugfs_create_file("available_events", 0444, d_tracer,
+                                    (void *)&show_event_seq_ops,
+                                    &ftrace_avail_fops);
+        if (!entry)
+                pr_warning("Could not create debugfs "
+                           "'available_events' entry\n");
+
         entry = debugfs_create_file("set_event", 0644, d_tracer,
                                     (void *)&show_set_event_seq_ops,
                                     &ftrace_set_event_fops);