[tip:perf/core] perf evlist: Fix inverted logic in perf_mmap__empty

[tip-bot for He Kuang <tipbot@zytor.com>]

Commit-ID:  8ea92ceb748535799e3e9f35afb85bdc23bf6d7c
Gitweb:     http://git.kernel.org/tip/8ea92ceb748535799e3e9f35afb85bdc23bf6d7c
Author:     He Kuang <hekuang@huawei.com>
AuthorDate: Tue, 7 Apr 2015 17:31:10 +0800
Committer:  Arnaldo Carvalho de Melo <acme@redhat.com>
CommitDate: Wed, 8 Apr 2015 09:06:58 -0300

perf evlist: Fix inverted logic in perf_mmap__empty

perf_evlist__mmap_consume() uses perf_mmap__empty() to judge whether
perf_mmap is empty and can be released. But the result is inverted so
fix it.

Signed-off-by: He Kuang <hekuang@huawei.com>
Tested-by: Arnaldo Carvalho de Melo <acme@redhat.com>
Cc: Jiri Olsa <jolsa@kernel.org>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Wang Nan <wangnan0@huawei.com>
Link: http://lkml.kernel.org/r/1428399071-7141-1-git-send-email-hekuang@huawei.com
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
---
 tools/perf/util/evlist.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/tools/perf/util/evlist.c b/tools/perf/util/evlist.c
index 82bf224..76ef7ee 100644
--- a/tools/perf/util/evlist.c
+++ b/tools/perf/util/evlist.c
@@ -695,7 +695,7 @@ union perf_event *perf_evlist__mmap_read(struct perf_evlist *evlist, int idx)
 
 static bool perf_mmap__empty(struct perf_mmap *md)
 {
-	return perf_mmap__read_head(md) != md->prev;
+	return perf_mmap__read_head(md) == md->prev;
 }
 
 static void perf_evlist__mmap_get(struct perf_evlist *evlist, int idx)