[PATCH 01/11] [BUGFIX] tracing: Return 0 if event_enable_funcsucceeded

[Masami Hiramatsu]

Return 0 instead of the number of activated ftrace if
event_enable_func succeeded and return an error code if failed,
beacuse 0 is success code at caller (ftrace_regex_write).

Without this fix, writing enable_event trigger on set_ftrace_filter
always doesn't work, since event_enable_func returns 1 to
ftrace_regex_write, it consumes 1 byte and pass input string
without the first character again. This makes event_enable_func
fail and disables event entry.

Signed-off-by: Masami Hiramatsu <masami.hiramatsu.pt@xxxxxxxxxxx>
Cc: Steven Rostedt <rostedt@xxxxxxxxxxx>
Cc: Frederic Weisbecker <fweisbec@xxxxxxxxx>
Cc: Ingo Molnar <mingo@xxxxxxxxxx>
Cc: Tom Zanussi <tom.zanussi@xxxxxxxxx>
---
 kernel/trace/trace_events.c |    5 ++++-
 1 file changed, 4 insertions(+), 1 deletion(-)

diff --git a/kernel/trace/trace_events.c b/kernel/trace/trace_events.c
index 53582e9..44ac836 100644
--- a/kernel/trace/trace_events.c
+++ b/kernel/trace/trace_events.c
@@ -2061,8 +2061,11 @@ event_enable_func(struct ftrace_hash *hash,
 	if (ret < 0)
 		goto out_put;
 	ret = register_ftrace_function_probe(glob, ops, data);
-	if (!ret)
+	if (!ret) {
+		ret = -ENOENT;
 		goto out_disable;
+	} else
+		ret = 0;
  out:
 	mutex_unlock(&event_mutex);
 	return ret;

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