tracing: Add __find_event_file() to find event files without restrict…

…ions By adding the function __find_event_file() that can search for files without restrictions, such as if the event associated with the file has a reg function, or if it has the "ignore" flag set, the files that are associated to ftrace internal events (like trace_marker and function events) can be found and used. find_event_file() still returns a "filtered" file, as most callers need a valid trace event file. One created by the trace_events.h macros and not one created for parsing ftrace specific events. Reviewed-by: Namhyung Kim <[email protected]> Signed-off-by: Steven Rostedt (VMware) <[email protected]>
josf · May 29, 2018 · 3c96529 · 3c96529
1 parent c94e45b
commit 3c96529
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Showing 2 changed files with 20 additions and 5 deletions.
diff --git a/kernel/trace/trace.h b/kernel/trace/trace.h
@@ -1454,6 +1454,9 @@ extern void trace_event_enable_tgid_record(bool enable);
 extern int event_trace_add_tracer(struct dentry *parent, struct trace_array *tr);
 extern int event_trace_del_tracer(struct trace_array *tr);
 
+extern struct trace_event_file *__find_event_file(struct trace_array *tr,
+						  const char *system,
+						  const char *event);
 extern struct trace_event_file *find_event_file(struct trace_array *tr,
 						const char *system,
 						const char *event);

diff --git a/kernel/trace/trace_events.c b/kernel/trace/trace_events.c
@@ -2473,8 +2473,9 @@ __trace_add_event_dirs(struct trace_array *tr)
 	}
 }
 
+/* Returns any file that matches the system and event */
 struct trace_event_file *
-find_event_file(struct trace_array *tr, const char *system,  const char *event)
+__find_event_file(struct trace_array *tr, const char *system, const char *event)
 {
 	struct trace_event_file *file;
 	struct trace_event_call *call;
@@ -2485,10 +2486,7 @@ find_event_file(struct trace_array *tr, const char *system,  const char *event)
 		call = file->event_call;
 		name = trace_event_name(call);
 
-		if (!name || !call->class || !call->class->reg)
-			continue;
-
-		if (call->flags & TRACE_EVENT_FL_IGNORE_ENABLE)
+		if (!name || !call->class)
 			continue;
 
 		if (strcmp(event, name) == 0 &&
@@ -2498,6 +2496,20 @@ find_event_file(struct trace_array *tr, const char *system,  const char *event)
 	return NULL;
 }
 
+/* Returns valid trace event files that match system and event */
+struct trace_event_file *
+find_event_file(struct trace_array *tr, const char *system, const char *event)
+{
+	struct trace_event_file *file;
+
+	file = __find_event_file(tr, system, event);
+	if (!file || !file->event_call->class->reg ||
+	    file->event_call->flags & TRACE_EVENT_FL_IGNORE_ENABLE)
+		return NULL;
+
+	return file;
+}
+
 #ifdef CONFIG_DYNAMIC_FTRACE
 
 /* Avoid typos */