tracing: fix event_subsystem ref counting

BugLink: http://bugs.launchpad.net/bugs/902312

commit cb59974742aea24adf6637eb0c4b8e7b48bca6fb upstream.

Fix a bug introduced by e9dbfae5, which prevents event_subsystem from
ever being released.

Ref_count was added to keep track of subsystem users, not for counting
events.  Subsystem is created with ref_count = 1, so there is no need to
increment it for every event, we have nr_events for that.  Fix this by
touching ref_count only when we actually have a new user -
subsystem_open().

Signed-off-by: Ilya Dryomov <idryomov@gmail.com>
Link: http://lkml.kernel.org/r/1320052062-7846-1-git-send-email-idryomov@gmail.com
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
Signed-off-by: Tim Gardner <tim.gardner@canonical.com>

1 files changed, 0 insertions, 1 deletions

diff --git a/kernel/trace/trace_events.c b/kernel/trace/trace_events.c
index 3e2a7c91c54..2d049368242 100644
--- a/kernel/trace/trace_events.c
+++ b/kernel/trace/trace_events.c
@@ -1096,7 +1096,6 @@ event_subsystem_dir(const char *name, struct dentry *d_events)
         /* First see if we did not already create this dir */
         list_for_each_entry(system, &event_subsystems, list) {
                 if (strcmp(system->name, name) == 0) {
-                        __get_system(system);
                         system->nr_events++;
                         return system->entry;
                 }