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@linux.intel.com>
Suggested-by: Arnaldo Carvalho de Melo <acme@redhat.com>
Acked-by: Jiri Olsa <jolsa@kernel.org>
Cc: Andi Kleen <ak@linux.intel.com>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Wang Nan <wangnan0@huawei.com>
Link: http://lkml.kernel.org/r/1520350567-80082-4-git-send-email-kan.liang@linux.intel.com
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>

diff --git a/tools/perf/util/mmap.c b/tools/perf/util/mmap.c
index 8c1d033638c2478a3edf82dde8fdd1bba5f81235..2933942abfe252edf0c5f6387cc23bb54a602f5b 100644 (file)
--- 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;
 }