tracing: Add an unreg_all() callback to trigger commands
Add a new unreg_all() callback that can be used to remove all
command-specific triggers from an event and arrange to have it called
whenever a trigger file is opened with O_TRUNC set.
Commands that don't want truncate semantics, or existing commands that
don't implement this function simply do nothing and their triggers
remain intact.
Link: http://lkml.kernel.org/r/2b7d62854d01f28c19185e1bbb8f826f385edfba.1449767187.git.tom.zanussi@linux.intel.com
Signed-off-by: Tom Zanussi <tom.zanussi@linux.intel.com>
Reviewed-by: Namhyung Kim <namhyung@kernel.org>
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
diff --git a/kernel/trace/trace.h b/kernel/trace/trace.h
index 8c6aefb..f4dd0ad 100644
--- a/kernel/trace/trace.h
+++ b/kernel/trace/trace.h
@@ -1298,8 +1298,8 @@
* it (filters make a trigger require access to the trace record
* but are not always present).
*
- * All the methods below, except for @set_filter(), must be
- * implemented.
+ * All the methods below, except for @set_filter() and @unreg_all(),
+ * must be implemented.
*
* @func: The callback function responsible for parsing and
* registering the trigger written to the 'trigger' file by the
@@ -1324,6 +1324,10 @@
* This is usually implemented by the generic utility function
* @unregister_trigger() (see trace_event_triggers.c).
*
+ * @unreg_all: An optional function called to remove all the triggers
+ * from the list of triggers associated with the event. Called
+ * when a trigger file is opened in truncate mode.
+ *
* @set_filter: An optional function called to parse and set a filter
* for the trigger. If no @set_filter() method is set for the
* event command, filters set by the user for the command will be
@@ -1350,6 +1354,7 @@
struct event_trigger_ops *ops,
struct event_trigger_data *data,
struct trace_event_file *file);
+ void (*unreg_all)(struct trace_event_file *file);
int (*set_filter)(char *filter_str,
struct event_trigger_data *data,
struct trace_event_file *file);