[PATCH v4 4/7] tracing: Add a per-event-trigger 'paused' field

[Tom Zanussi <tom.zanussi@linux.intel.com>]

Add a simple per-trigger 'paused' flag, allowing individual triggers
to pause.  We could leave it to individual triggers that need this
functionality to do it themselves, but we also want to allow other
events to control pausing, so add it to the trigger data.

Signed-off-by: Tom Zanussi <tom.zanussi@linux.intel.com>
---
 kernel/trace/trace.h                | 1 +
 kernel/trace/trace_events_trigger.c | 4 ++++
 2 files changed, 5 insertions(+)

diff --git a/kernel/trace/trace.h b/kernel/trace/trace.h
index 3d38c2e..5bc1752 100644
--- a/kernel/trace/trace.h
+++ b/kernel/trace/trace.h
@@ -1110,6 +1110,7 @@ struct event_trigger_data {
 	struct event_filter __rcu	*filter;
 	char				*filter_str;
 	void				*private_data;
+	bool				paused;
 	struct list_head		list;
 };
 
diff --git a/kernel/trace/trace_events_trigger.c b/kernel/trace/trace_events_trigger.c
index a8dfd4e..010ce30 100644
--- a/kernel/trace/trace_events_trigger.c
+++ b/kernel/trace/trace_events_trigger.c
@@ -73,6 +73,8 @@ event_triggers_call(struct ftrace_event_file *file, void *rec)
 		return tt;
 
 	list_for_each_entry_rcu(data, &file->triggers, list) {
+		if (data->paused)
+			continue;
 		if (!rec) {
 			data->ops->func(data, rec);
 			continue;
@@ -110,6 +112,8 @@ event_triggers_post_call(struct ftrace_event_file *file,
 	struct event_trigger_data *data;
 
 	list_for_each_entry_rcu(data, &file->triggers, list) {
+		if (data->paused)
+			continue;
 		if (data->cmd_ops->trigger_type & tt)
 			data->ops->func(data, rec);
 	}
-- 
1.9.3