perf unwind: Add initialized arg into unwind__prepare_access

Adding initialized arg into unwind__prepare_access to get feedback about
the initialization state.

It's not possible to get it from error code, because we return 0 even in
case we don't recognize dso, which is valid.

The 'initialized' value is used in following patch to speedup
unwind__prepare_access calls logic in fork path.

Signed-off-by: Jiri Olsa <jolsa@kernel.org>
Cc: David Ahern <dsahern@gmail.com>
Cc: He Kuang <hekuang@huawei.com>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Link: http://lkml.kernel.org/r/1467634583-29147-4-git-send-email-jolsa@kernel.org
[ Remove ; after static inline function signatures, fixes build break ]
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>

tools/perf/util/thread.c

@@ -202,7 +202,7 @@ int thread__insert_map(struct thread *thread, struct map *map)
 {
 	int ret;
 
-	ret = unwind__prepare_access(thread, map);
+	ret = unwind__prepare_access(thread, map, NULL);
 	if (ret)
 		return ret;
 

tools/perf/util/unwind-libunwind.c

@@ -14,15 +14,19 @@ static void unwind__register_ops(struct thread *thread,
 	thread->unwind_libunwind_ops = ops;
 }
 
-int unwind__prepare_access(struct thread *thread, struct map *map)
+int unwind__prepare_access(struct thread *thread, struct map *map,
+			   bool *initialized)
 {
 	const char *arch;
 	enum dso_type dso_type;
 	struct unwind_libunwind_ops *ops = local_unwind_libunwind_ops;
+	int err;
 
 	if (thread->addr_space) {
 		pr_debug("unwind: thread map already set, dso=%s\n",
 			 map->dso->name);
+		if (initialized)
+			*initialized = true;
 		return 0;
 	}
 
@@ -51,7 +55,10 @@ int unwind__prepare_access(struct thread *thread, struct map *map)
 out_register:
 	unwind__register_ops(thread, ops);
 
-	return thread->unwind_libunwind_ops->prepare_access(thread);
+	err = thread->unwind_libunwind_ops->prepare_access(thread);
+	if (initialized)
+		*initialized = err ? false : true;
+	return err;
 }
 
 void unwind__flush_access(struct thread *thread)

tools/perf/util/unwind.h

@@ -42,12 +42,14 @@ int unwind__get_entries(unwind_entry_cb_t cb, void *arg,
 #endif
 
 int LIBUNWIND__ARCH_REG_ID(int regnum);
-int unwind__prepare_access(struct thread *thread, struct map *map);
+int unwind__prepare_access(struct thread *thread, struct map *map,
+			   bool *initialized);
 void unwind__flush_access(struct thread *thread);
 void unwind__finish_access(struct thread *thread);
 #else
 static inline int unwind__prepare_access(struct thread *thread __maybe_unused,
-					 struct map *map __maybe_unused)
+					 struct map *map __maybe_unused,
+					 bool *initialized __maybe_unused)
 {
 	return 0;
 }
@@ -67,7 +69,8 @@ unwind__get_entries(unwind_entry_cb_t cb __maybe_unused,
 }
 
 static inline int unwind__prepare_access(struct thread *thread __maybe_unused,
-					 struct map *map __maybe_unused)
+					 struct map *map __maybe_unused,
+					 bool *initialized __maybe_unused)
 {
 	return 0;
 }