[tip:perf/core] perf tools: Fix PMU object alias initialization

[tip-bot for Jiri Olsa <jolsa@redhat.com>]

Commit-ID:  3fded963cdae12ff891a55efc866437506c3f912
Gitweb:     http://git.kernel.org/tip/3fded963cdae12ff891a55efc866437506c3f912
Author:     Jiri Olsa <jolsa@redhat.com>
AuthorDate: Wed, 10 Oct 2012 14:53:16 +0200
Committer:  Ingo Molnar <mingo@kernel.org>
CommitDate: Wed, 24 Oct 2012 10:41:26 +0200

perf tools: Fix PMU object alias initialization

The pmu_lookup should return pmus that do not expose the 'events'
group attribute in sysfs. Also it should fail when any other error
during 'events' lookup is hit (pmu_aliases fails).

Signed-off-by: Jiri Olsa <jolsa@redhat.com>
Cc: Arnaldo Carvalho de Melo <acme@ghostprotocols.net>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Corey Ashford <cjashfor@linux.vnet.ibm.com>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Stephane Eranian <eranian@google.com>
Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Link: http://lkml.kernel.org/r/1349873598-12583-7-git-send-email-jolsa@redhat.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
---
 tools/perf/util/pmu.c |    7 ++++---
 1 files changed, 4 insertions(+), 3 deletions(-)

diff --git a/tools/perf/util/pmu.c b/tools/perf/util/pmu.c
index 8a2229d..18e8480 100644
--- a/tools/perf/util/pmu.c
+++ b/tools/perf/util/pmu.c
@@ -164,7 +164,7 @@ static int pmu_aliases(char *name, struct list_head *head)
 		 "%s/bus/event_source/devices/%s/events", sysfs, name);
 
 	if (stat(path, &st) < 0)
-		return -1;
+		return 0;	 /* no error if 'events' does not exist */
 
 	if (pmu_aliases_parse(path, head))
 		return -1;
@@ -296,6 +296,9 @@ static struct perf_pmu *pmu_lookup(char *name)
 	if (pmu_format(name, &format))
 		return NULL;
 
+	if (pmu_aliases(name, &aliases))
+		return NULL;
+
 	if (pmu_type(name, &type))
 		return NULL;
 
@@ -305,8 +308,6 @@ static struct perf_pmu *pmu_lookup(char *name)
 
 	pmu->cpus = pmu_cpumask(name);
 
-	pmu_aliases(name, &aliases);
-
 	INIT_LIST_HEAD(&pmu->format);
 	INIT_LIST_HEAD(&pmu->aliases);
 	list_splice(&format, &pmu->format);