On Thu, 1 Oct 2020 at 02:30, Andrii Nakryiko [off-list ref] wrote:

quoted

diff --git a/tools/lib/bpf/libbpf.c b/tools/lib/bpf/libbpf.c
index 32dc444224d8..5412aa7169db 100644
--- a/tools/lib/bpf/libbpf.c
+++ b/tools/lib/bpf/libbpf.c

@@ -4215,7 +4215,7 @@ bpf_object__create_maps(struct bpf_object *obj)
                if (map->fd >= 0) {
                        pr_debug("map '%s': skipping creation (preset fd=%d)\n",
                                 map->name, map->fd);
-                       continue;
+                       goto check_pin_path;
                }

                err = bpf_object__create_map(obj, map);

@@ -4258,6 +4258,7 @@ bpf_object__create_maps(struct bpf_object *obj)
                        map->init_slots_sz = 0;
                }

+check_pin_path:
                if (map->pin_path && !map->pinned) {
                        err = bpf_map__pin(map, NULL);
                        if (err) {

Do you think if this change be better?

Yes, of course. Just don't do it through use of goto. Guard map
creation with that if instead.

Hi Andrii,

Looks I missed something, Would you like to explain why we should not use goto?
And for "guard map creation with the if", do you mean duplicate the
if (map->pin_path && !map->pinned) in if (map->fd >= 0)? like

diff --git a/src/libbpf.c b/src/libbpf.c
index 3df1f4d..705abcb 100644
--- a/src/libbpf.c
+++ b/src/libbpf.c

@@ -4215,6 +4215,15 @@ bpf_object__create_maps(struct bpf_object *obj)
                if (map->fd >= 0) {
                        pr_debug("map '%s': skipping creation (preset fd=%d)\n",
                                 map->name, map->fd);
+                       if (map->pin_path && !map->pinned) {
+                               err = bpf_map__pin(map, NULL);
+                               if (err) {
+                                       pr_warn("map '%s': failed to

auto-pin at '%s': %d\n",
+                                               map->name, map->pin_path, err);
+                                       zclose(map->fd);
+                                       goto err_out;
+                               }
+                       }
                        continue;
                }

(Sorry if the code format got corrupted as I replied in web gmail....)

Thanks
Hangbin