[for-next][PATCH 04/19] tracing: Add __find_event_file() to find event files without restrictions

From: Steven Rostedt
Date: Tue May 29 2018 - 11:23:39 EST


From: "Steven Rostedt (VMware)" <rostedt@xxxxxxxxxxx>

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 <namhyung@xxxxxxxxxx>
Signed-off-by: Steven Rostedt (VMware) <rostedt@xxxxxxxxxxx>
---
kernel/trace/trace.h | 3 +++
kernel/trace/trace_events.c | 22 +++++++++++++++++-----
2 files changed, 20 insertions(+), 5 deletions(-)

diff --git a/kernel/trace/trace.h b/kernel/trace/trace.h
index 6bfc2467479c..07c43960a704 100644
--- 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
index 05c7172c6667..caf76355f0a3 100644
--- 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 */
--
2.17.0