ftrace: Allow for function tracing instance to filter functions

Create a "set_ftrace_filter" and "set_ftrace_notrace" files in the instance
directories to let users filter of functions to trace for the given instance.

Signed-off-by: Steven Rostedt <rostedt@goodmis.org>

1 files changed, 32 insertions, 8 deletions

diff --git a/kernel/trace/trace_functions.c b/kernel/trace/trace_functions.c
index 3f8dc1ce8b9c..5b781d2be383 100644
--- a/kernel/trace/trace_functions.c
+++ b/kernel/trace/trace_functions.c
@@ -52,10 +52,34 @@ static int allocate_ftrace_ops(struct trace_array *tr)
         return 0;
 }
 
+
+int ftrace_create_function_files(struct trace_array *tr,
+                                 struct dentry *parent)
+{
+        int ret;
+
+        /* The top level array uses the "global_ops". */
+        if (!(tr->flags & TRACE_ARRAY_FL_GLOBAL)) {
+                ret = allocate_ftrace_ops(tr);
+                if (ret)
+                        return ret;
+        }
+
+        ftrace_create_filter_files(tr->ops, parent);
+
+        return 0;
+}
+
+void ftrace_destroy_function_files(struct trace_array *tr)
+{
+        ftrace_destroy_filter_files(tr->ops);
+        kfree(tr->ops);
+        tr->ops = NULL;
+}
+
 static int function_trace_init(struct trace_array *tr)
 {
         struct ftrace_ops *ops;
-        int ret;
 
         if (tr->flags & TRACE_ARRAY_FL_GLOBAL) {
                 /* There's only one global tr */
@@ -69,10 +93,13 @@ static int function_trace_init(struct trace_array *tr)
                 else
                         ops = &trace_ops;
                 tr->ops = ops;
-        } else {
-                ret = allocate_ftrace_ops(tr);
-                if (ret)
-                        return ret;
+        } else if (!tr->ops) {
+                /*
+                 * Instance trace_arrays get their ops allocated
+                 * at instance creation. Unless it failed
+                 * the allocation.
+                 */
+                return -ENOMEM;
         }
 
         tr->trace_buffer.cpu = get_cpu();
@@ -87,9 +114,6 @@ static void function_trace_reset(struct trace_array *tr)
 {
         tracing_stop_function_trace(tr);
         tracing_stop_cmdline_record();
-        if (!(tr->flags & TRACE_ARRAY_FL_GLOBAL))
-                kfree(tr->ops);
-        tr->ops = NULL;
 }
 
 static void function_trace_start(struct trace_array *tr)