[tip:perf/core] perf evlist: Choose correct reading direction according to evlist->backward

[tip-bot for Wang Nan]

Commit-ID:  5a5ddeb6e3559675070df6b39ba32a4dd1ab4dd5
Gitweb:     http://git.kernel.org/tip/5a5ddeb6e3559675070df6b39ba32a4dd1ab4dd5
Author:     Wang Nan <wangnan0@xxxxxxxxxx>
AuthorDate: Wed, 25 May 2016 13:44:50 +0000
Committer:  Arnaldo Carvalho de Melo <acme@xxxxxxxxxx>
CommitDate: Mon, 30 May 2016 12:41:45 -0300

perf evlist: Choose correct reading direction according to evlist->backward

Now we have evlist->backward to indicate the mmap direction. Make
perf_evlist__mmap_read() choose right direction automatically.

Signed-off-by: Wang Nan <wangnan0@xxxxxxxxxx>
Cc: He Kuang <hekuang@xxxxxxxxxx>
Cc: Jiri Olsa <jolsa@xxxxxxxxxx>
Cc: Masami Hiramatsu <mhiramat@xxxxxxxxxx>
Cc: Namhyung Kim <namhyung@xxxxxxxxxx>
Cc: Zefan Li <lizefan@xxxxxxxxxx>
Cc: pi3orama@xxxxxxx
Link: http://lkml.kernel.org/r/1464183898-174512-3-git-send-email-wangnan0@xxxxxxxxxx
Signed-off-by: Arnaldo Carvalho de Melo <acme@xxxxxxxxxx>
---
 tools/perf/util/evlist.c | 9 ++++++++-
 tools/perf/util/evlist.h | 2 ++
 2 files changed, 10 insertions(+), 1 deletion(-)

diff --git a/tools/perf/util/evlist.c b/tools/perf/util/evlist.c
index 58ede32..719729e 100644
--- a/tools/perf/util/evlist.c
+++ b/tools/perf/util/evlist.c
@@ -777,7 +777,7 @@ broken_event:
 	return event;
 }
 
-union perf_event *perf_evlist__mmap_read(struct perf_evlist *evlist, int idx)
+union perf_event *perf_evlist__mmap_read_forward(struct perf_evlist *evlist, int idx)
 {
 	struct perf_mmap *md = &evlist->mmap[idx];
 	u64 head;
@@ -832,6 +832,13 @@ perf_evlist__mmap_read_backward(struct perf_evlist *evlist, int idx)
 	return perf_mmap__read(md, false, start, end, &md->prev);
 }
 
+union perf_event *perf_evlist__mmap_read(struct perf_evlist *evlist, int idx)
+{
+	if (!evlist->backward)
+		return perf_evlist__mmap_read_forward(evlist, idx);
+	return perf_evlist__mmap_read_backward(evlist, idx);
+}
+
 void perf_evlist__mmap_read_catchup(struct perf_evlist *evlist, int idx)
 {
 	struct perf_mmap *md = &evlist->mmap[idx];
diff --git a/tools/perf/util/evlist.h b/tools/perf/util/evlist.h
index d740fb8..68cb136 100644
--- a/tools/perf/util/evlist.h
+++ b/tools/perf/util/evlist.h
@@ -131,6 +131,8 @@ struct perf_sample_id *perf_evlist__id2sid(struct perf_evlist *evlist, u64 id);
 
 union perf_event *perf_evlist__mmap_read(struct perf_evlist *evlist, int idx);
 
+union perf_event *perf_evlist__mmap_read_forward(struct perf_evlist *evlist,
+						 int idx);
 union perf_event *perf_evlist__mmap_read_backward(struct perf_evlist *evlist,
 						  int idx);
 void perf_evlist__mmap_read_catchup(struct perf_evlist *evlist, int idx);