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Subject[PATCH v4 03/12] tracing: Add synth_event_delete()
Date
create_or_delete_synth_event() contains code to delete a synthetic
event, which would be useful on its own - specifically, it would be
useful to allow event-creating modules to call it separately.

Separate out the delete code from that function and create an exported
function named synth_event_delete().

Signed-off-by: Tom Zanussi <zanussi@kernel.org>
Acked-by: Masami Hiramatsu <mhiramat@kernel.org>
---
include/linux/trace_events.h | 2 ++
kernel/trace/trace_events_hist.c | 57 +++++++++++++++++++++++++++++-----------
2 files changed, 43 insertions(+), 16 deletions(-)

diff --git a/include/linux/trace_events.h b/include/linux/trace_events.h
index 8d621a73c97e..25fe743bcbaf 100644
--- a/include/linux/trace_events.h
+++ b/include/linux/trace_events.h
@@ -354,6 +354,8 @@ extern struct trace_event_file *trace_get_event_file(const char *instance,
const char *event);
extern void trace_put_event_file(struct trace_event_file *file);

+extern int synth_event_delete(const char *name);
+
/*
* Event file flags:
* ENABLED - The event is enabled
diff --git a/kernel/trace/trace_events_hist.c b/kernel/trace/trace_events_hist.c
index c322826e0726..21e316732700 100644
--- a/kernel/trace/trace_events_hist.c
+++ b/kernel/trace/trace_events_hist.c
@@ -1360,29 +1360,54 @@ static int __create_synth_event(int argc, const char *name, const char **argv)
goto out;
}

+static int destroy_synth_event(struct synth_event *se)
+{
+ int ret;
+
+ if (se->ref)
+ ret = -EBUSY;
+ else {
+ ret = unregister_synth_event(se);
+ if (!ret) {
+ dyn_event_remove(&se->devent);
+ free_synth_event(se);
+ }
+ }
+
+ return ret;
+}
+
+/**
+ * synth_event_delete - Delete a synthetic event
+ * @event_name: The name of the new sythetic event
+ *
+ * Delete a synthetic event that was created with synth_event_create().
+ *
+ * Return: 0 if successful, error otherwise.
+ */
+int synth_event_delete(const char *event_name)
+{
+ struct synth_event *se = NULL;
+ int ret = -ENOENT;
+
+ mutex_lock(&event_mutex);
+ se = find_synth_event(event_name);
+ if (se)
+ ret = destroy_synth_event(se);
+ mutex_unlock(&event_mutex);
+
+ return ret;
+}
+EXPORT_SYMBOL_GPL(synth_event_delete);
+
static int create_or_delete_synth_event(int argc, char **argv)
{
const char *name = argv[0];
- struct synth_event *event = NULL;
int ret;

/* trace_run_command() ensures argc != 0 */
if (name[0] == '!') {
- mutex_lock(&event_mutex);
- event = find_synth_event(name + 1);
- if (event) {
- if (event->ref)
- ret = -EBUSY;
- else {
- ret = unregister_synth_event(event);
- if (!ret) {
- dyn_event_remove(&event->devent);
- free_synth_event(event);
- }
- }
- } else
- ret = -ENOENT;
- mutex_unlock(&event_mutex);
+ ret = synth_event_delete(name + 1);
return ret;
}

--
2.14.1
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