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Commit a88e1cfb authored by Tom Zanussi's avatar Tom Zanussi Committed by Steven Rostedt
Browse files

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: default avatarTom Zanussi <tom.zanussi@linux.intel.com>
Reviewed-by: default avatarNamhyung Kim <namhyung@kernel.org>
Signed-off-by: default avatarSteven Rostedt <rostedt@goodmis.org>
parent a5863dae

kernel/trace/trace.h

+7 −2
Original line number Diff line number Diff line
@@ -1298,8 +1298,8 @@ struct event_trigger_ops { 
 *	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 @@ struct event_trigger_ops { 
 *	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_command { 
					 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);

kernel/trace/trace_events_trigger.c

+13 −0
Original line number Diff line number Diff line
@@ -193,6 +193,19 @@ static int event_trigger_regex_open(struct inode *inode, struct file *file) 
		return -ENODEV;

	}



	if ((file->f_mode & FMODE_WRITE) &&

	    (file->f_flags & O_TRUNC)) {

		struct trace_event_file *event_file;

		struct event_command *p;



		event_file = event_file_data(file);



		list_for_each_entry(p, &trigger_commands, list) {

			if (p->unreg_all)

				p->unreg_all(event_file);

		}

	}



	if (file->f_mode & FMODE_READ) {

		ret = seq_open(file, &event_triggers_seq_ops);

		if (!ret) {