Commit 2c193d32 authored Oct 06, 2020 by Hangbin Liu Committed by Alexei Starovoitov Oct 06, 2020

libbpf: Check if pin_path was set even map fd exist



Say a user reuse map fd after creating a map manually and set the
pin_path, then load the object via libbpf.

In libbpf bpf_object__create_maps(), bpf_object__reuse_map() will
return 0 if there is no pinned map in map->pin_path. Then after
checking if map fd exist, we should also check if pin_path was set
and do bpf_map__pin() instead of continue the loop.

Fix it by creating map if fd not exist and continue checking pin_path
after that.

Suggested-by: Andrii Nakryiko <andrii.nakryiko@gmail.com>
Signed-off-by: Hangbin Liu <liuhangbin@gmail.com>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Acked-by: Andrii Nakryiko <andrii@kernel.org>
Link: https://lore.kernel.org/bpf/20201006021345.3817033-3-liuhangbin@gmail.com

parent a0f2b7ac

tools/lib/bpf/libbpf.c

+18 −19

Original line number	Diff line number	Diff line
		@@ -4256,15 +4256,13 @@ 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;
		}

		} else {
		err = bpf_object__create_map(obj, map);
		if (err)
		goto err_out;

		pr_debug("map '%s': created successfully, fd=%d\n", map->name,
		map->fd);
		pr_debug("map '%s': created successfully, fd=%d\n",
		map->name, map->fd);

		if (bpf_map__is_internal(map)) {
		err = bpf_object__populate_internal_map(obj, map);
		@@ -4281,6 +4279,7 @@ bpf_object__create_maps(struct bpf_object *obj)
		goto err_out;
		}
		}
		}

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

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