perf evsel: Set leader evsel's ->leader to itself

Currently only non-leader members are set ->leader to the leader evsel
of the group and the leader has set NULL.  Thus it requires special
casing for leader evsels.  Set ->leader to itself will remove this.

Suggested-by: Arnaldo Carvalho de Melo <acme@ghostprotocols.net>
Signed-off-by: Namhyung Kim <namhyung@kernel.org>
Acked-by: Jiri Olsa <jolsa@redhat.com>
Cc: Andi Kleen <andi@firstfloor.org>
Cc: Ingo Molnar <mingo@kernel.org>
Cc: Jiri Olsa <jolsa@redhat.com>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Stephane Eranian <eranian@google.com>
Link: http://lkml.kernel.org/r/1354171126-14387-3-git-send-email-namhyung@kernel.org
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>

tools/perf/util/evlist.c

@@ -111,7 +111,6 @@ void __perf_evlist__set_leader(struct list_head *list)
 	struct perf_evsel *evsel, *leader;
 
 	leader = list_entry(list->next, struct perf_evsel, node);
-	leader->leader = NULL;
 
 	list_for_each_entry(evsel, list, node) {
 		if (evsel != leader)

tools/perf/util/evsel.c

@@ -55,6 +55,7 @@ void perf_evsel__init(struct perf_evsel *evsel,
 {
 	evsel->idx	   = idx;
 	evsel->attr	   = *attr;
+	evsel->leader	   = evsel;
 	INIT_LIST_HEAD(&evsel->node);
 	hists__init(&evsel->hists);
 	evsel->sample_size = __perf_evsel__sample_size(attr->sample_type);

tools/perf/util/evsel.h

@@ -228,6 +228,6 @@ static inline struct perf_evsel *perf_evsel__next(struct perf_evsel *evsel)
 
 static inline bool perf_evsel__is_group_member(const struct perf_evsel *evsel)
 {
-	return evsel->leader != NULL;
+	return evsel->leader != evsel;
 }
 #endif /* __PERF_EVSEL_H */