[tip:perf/core] perf mmap: Use the stored data in perf_mmap__read_event()

From: tip-bot for Kan Liang
Date: Fri Mar 09 2018 - 03:45:24 EST


Commit-ID: b9de0f6e507b2f0ee305aba338b79941deb5a461
Gitweb: https://git.kernel.org/tip/b9de0f6e507b2f0ee305aba338b79941deb5a461
Author: Kan Liang <kan.liang@xxxxxxxxxxxxxxx>
AuthorDate: Tue, 6 Mar 2018 10:36:03 -0500
Committer: Arnaldo Carvalho de Melo <acme@xxxxxxxxxx>
CommitDate: Thu, 8 Mar 2018 10:05:51 -0300

perf mmap: Use the stored data in perf_mmap__read_event()

Using the 'start', 'end' and 'overwrite' which are stored in
struct perf_mmap to replace the parameters of perf_mmap__read_event().
The parameters will be discarded later.

No functional change.

Signed-off-by: Kan Liang <kan.liang@xxxxxxxxxxxxxxx>
Suggested-by: Arnaldo Carvalho de Melo <acme@xxxxxxxxxx>
Acked-by: Jiri Olsa <jolsa@xxxxxxxxxx>
Cc: Andi Kleen <ak@xxxxxxxxxxxxxxx>
Cc: Namhyung Kim <namhyung@xxxxxxxxxx>
Cc: Wang Nan <wangnan0@xxxxxxxxxx>
Link: http://lkml.kernel.org/r/1520350567-80082-4-git-send-email-kan.liang@xxxxxxxxxxxxxxx
Signed-off-by: Arnaldo Carvalho de Melo <acme@xxxxxxxxxx>
---
tools/perf/util/mmap.c | 18 ++++++++----------
1 file changed, 8 insertions(+), 10 deletions(-)

diff --git a/tools/perf/util/mmap.c b/tools/perf/util/mmap.c
index 8c1d033638c2..2933942abfe2 100644
--- a/tools/perf/util/mmap.c
+++ b/tools/perf/util/mmap.c
@@ -76,8 +76,9 @@ static union perf_event *perf_mmap__read(struct perf_mmap *map,
* perf_mmap__read_done()
*/
union perf_event *perf_mmap__read_event(struct perf_mmap *map,
- bool overwrite,
- u64 *startp, u64 end)
+ bool overwrite __maybe_unused,
+ u64 *startp __maybe_unused,
+ u64 end __maybe_unused)
{
union perf_event *event;

@@ -87,17 +88,14 @@ union perf_event *perf_mmap__read_event(struct perf_mmap *map,
if (!refcount_read(&map->refcnt))
return NULL;

- if (startp == NULL)
- return NULL;
-
/* non-overwirte doesn't pause the ringbuffer */
- if (!overwrite)
- end = perf_mmap__read_head(map);
+ if (!map->overwrite)
+ map->end = perf_mmap__read_head(map);

- event = perf_mmap__read(map, startp, end);
+ event = perf_mmap__read(map, &map->start, map->end);

- if (!overwrite)
- map->prev = *startp;
+ if (!map->overwrite)
+ map->prev = map->start;

return event;
}