tracing: Fix tracing_stat return values in error handling paths

commit afccc00f75bbbee4e4ae833a96c2d29a7259c693 upstream.

tracing_stat_init() was always returning '0', even on the error paths.  It
now returns -ENODEV if tracing_init_dentry() fails or -ENOMEM if it fails
to created the 'trace_stat' debugfs directory.

Link: http://lkml.kernel.org/r/1410299381-20108-1-git-send-email-luis.henriques@canonical.com
Fixes: ed6f1c996bfe4 ("tracing: Check return value of tracing_init_dentry()")
Signed-off-by: Luis Henriques <luis.henriques@canonical.com>
[ Pulled from the archeological digging of my INBOX ]
Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
[bwh: Backported to 3.16: adjust context]
Signed-off-by: Ben Hutchings <ben@decadent.org.uk>

diff --git a/kernel/trace/trace_stat.c b/kernel/trace/trace_stat.c
index 4f2f38e4726d0e739c61ff87a4d72adc324d3a96..9457c39e8d3c161ccdf31f86fef683a8fcec1932 100644 (file)
--- a/kernel/trace/trace_stat.c
+++ b/kernel/trace/trace_stat.c
@@ -277,19 +277,23 @@ static int tracing_stat_init(void)
 
        d_tracing = tracing_init_dentry();
        if (!d_tracing)
-               return 0;
+               return -ENODEV;
 
        stat_dir = debugfs_create_dir("trace_stat", d_tracing);
-       if (!stat_dir)
+       if (!stat_dir) {
                pr_warning("Could not create debugfs "
                           "'trace_stat' entry\n");
+               return -ENOMEM;
+       }
        return 0;
 }
 
 static int init_stat_file(struct stat_session *session)
 {
-       if (!stat_dir && tracing_stat_init())
-               return -ENODEV;
+       int ret;
+
+       if (!stat_dir && (ret = tracing_stat_init()))
+               return ret;
 
        session->file = debugfs_create_file(session->ts->name, 0644,
                                            stat_dir,