[tip:perf/urgent] perf thread_map: Introduce thread_map__reset function

[tip-bot for Jiri Olsa <tipbot@zytor.com>]

Commit-ID:  62eea464380633b88902da35bf9cbd8515289703
Gitweb:     http://git.kernel.org/tip/62eea464380633b88902da35bf9cbd8515289703
Author:     Jiri Olsa <jolsa@kernel.org>
AuthorDate: Fri, 26 Jun 2015 11:29:06 +0200
Committer:  Arnaldo Carvalho de Melo <acme@redhat.com>
CommitDate: Fri, 26 Jun 2015 11:03:41 -0300

perf thread_map: Introduce thread_map__reset function

We need to reset newly allocated 'struct thread_map_data' entries,
because we will introduce new comm memeber, which will get set later or
not at all.

Signed-off-by: Jiri Olsa <jolsa@kernel.org>
Cc: Adrian Hunter <adrian.hunter@intel.com>
Cc: Andi Kleen <ak@linux.intel.com>
Cc: David Ahern <dsahern@gmail.com>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Stephane Eranian <eranian@google.com>
Link: http://lkml.kernel.org/r/1435310967-14570-2-git-send-email-jolsa@kernel.org
[ Use sizeof(map->map[0]) to be independent of the array entry type ]
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
---
 tools/perf/util/thread_map.c | 17 ++++++++++++++++-
 1 file changed, 16 insertions(+), 1 deletion(-)

diff --git a/tools/perf/util/thread_map.c b/tools/perf/util/thread_map.c
index 368cc58..ed76c17 100644
--- a/tools/perf/util/thread_map.c
+++ b/tools/perf/util/thread_map.c
@@ -21,11 +21,26 @@ static int filter(const struct dirent *dir)
 		return 1;
 }
 
+static void thread_map__reset(struct thread_map *map, int start, int nr)
+{
+	size_t size = (nr - start) * sizeof(map->map[0]);
+
+	memset(&map->map[start], 0, size);
+}
+
 static struct thread_map *thread_map__realloc(struct thread_map *map, int nr)
 {
 	size_t size = sizeof(*map) + sizeof(map->map[0]) * nr;
+	int start = map ? map->nr : 0;
 
-	return realloc(map, size);
+	map = realloc(map, size);
+	/*
+	 * We only realloc to add more items, let's reset new items.
+	 */
+	if (map)
+		thread_map__reset(map, start, nr);
+
+	return map;
 }
 
 #define thread_map__alloc(__nr) thread_map__realloc(NULL, __nr)