perf tools: Replace map->referenced & maps->removed_maps with map->refcnt

Use just reference counts, so that when no more hist_entry instances
references a map and the thread instance goes away by processing a
PERF_RECORD_EXIT, we can delete the maps.

Cc: Adrian Hunter <adrian.hunter@intel.com>
Cc: Borislav Petkov <bp@suse.de>
Cc: David Ahern <dsahern@gmail.com>
Cc: Don Zickus <dzickus@redhat.com>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Jiri Olsa <jolsa@redhat.com>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Stephane Eranian <eranian@google.com>
Link: http://lkml.kernel.org/n/tip-oym7lfhcc7ss6xpz44h7nbxs@git.kernel.org
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
diff --git a/tools/perf/util/map.h b/tools/perf/util/map.h
index b8df09d..d73e687 100644
--- a/tools/perf/util/map.h
+++ b/tools/perf/util/map.h
@@ -34,7 +34,6 @@
 	u64			start;
 	u64			end;
 	u8 /* enum map_type */	type;
-	bool			referenced;
 	bool			erange_warned;
 	u32			priv;
 	u32			prot;
@@ -63,7 +62,6 @@
 struct maps {
 	struct rb_root	 entries;
 	pthread_rwlock_t lock;
-	struct list_head removed_maps;
 };
 
 struct map_groups {
@@ -161,6 +159,14 @@
 
 void map__put(struct map *map);
 
+static inline void __map__zput(struct map **map)
+{
+	map__put(*map);
+	*map = NULL;
+}
+
+#define map__zput(map) __map__zput(&map)
+
 int map__overlap(struct map *l, struct map *r);
 size_t map__fprintf(struct map *map, FILE *fp);
 size_t map__fprintf_dsoname(struct map *map, FILE *fp);