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.

Cc: He Kuang <heku...@huawei.com>
Link: http://lkml.kernel.org/n/tip-vzmw5piz7diqa7rd6c49m...@git.kernel.org
Signed-off-by: Jiri Olsa <jo...@kernel.org>
---
 tools/perf/util/thread.c           |  2 +-
 tools/perf/util/unwind-libunwind.c | 11 +++++++++--
 tools/perf/util/unwind.h           |  9 ++++++---
 3 files changed, 16 insertions(+), 6 deletions(-)

diff --git a/tools/perf/util/thread.c b/tools/perf/util/thread.c
index f30f9566fddc..2439b122a4e4 100644
--- a/tools/perf/util/thread.c
+++ b/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;
 
diff --git a/tools/perf/util/unwind-libunwind.c 
b/tools/perf/util/unwind-libunwind.c
index 854711966cad..6d542a4e0648 100644
--- a/tools/perf/util/unwind-libunwind.c
+++ b/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)
diff --git a/tools/perf/util/unwind.h b/tools/perf/util/unwind.h
index 84c6d44d52f9..17ea1f928f13 100644
--- a/tools/perf/util/unwind.h
+++ b/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;
 }
-- 
2.4.11

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