6.6-stable review patch. If anyone has any objections, please let me know.
------------------
From: Eduard Zingerman eddyz87@gmail.com
[ Upstream commit fe9d049c3da06373a1a35914b7f695509e4cb1fe ]
Automatically select which struct_ops programs to load depending on which struct_ops maps are selected for automatic creation. E.g. for the BPF code below:
SEC("struct_ops/test_1") int BPF_PROG(foo) { ... } SEC("struct_ops/test_2") int BPF_PROG(bar) { ... }
SEC(".struct_ops.link") struct test_ops___v1 A = { .foo = (void *)foo };
SEC(".struct_ops.link") struct test_ops___v2 B = { .foo = (void *)foo, .bar = (void *)bar, };
And the following libbpf API calls:
bpf_map__set_autocreate(skel->maps.A, true); bpf_map__set_autocreate(skel->maps.B, false);
The autoload would be enabled for program 'foo' and disabled for program 'bar'.
During load, for each struct_ops program P, referenced from some struct_ops map M: - set P.autoload = true if M.autocreate is true for some M; - set P.autoload = false if M.autocreate is false for all M; - don't change P.autoload, if P is not referenced from any map.
Do this after bpf_object__init_kern_struct_ops_maps() to make sure that shadow vars assignment is done.
Signed-off-by: Eduard Zingerman eddyz87@gmail.com Signed-off-by: Andrii Nakryiko andrii@kernel.org Link: https://lore.kernel.org/bpf/20240306104529.6453-9-eddyz87@gmail.com Stable-dep-of: 04a94133f1b3 ("libbpf: Don't take direct pointers into BTF data from st_ops") Signed-off-by: Sasha Levin sashal@kernel.org --- tools/lib/bpf/libbpf.c | 43 ++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 43 insertions(+)
diff --git a/tools/lib/bpf/libbpf.c b/tools/lib/bpf/libbpf.c index c91917868b557..aeed9bc44247b 100644 --- a/tools/lib/bpf/libbpf.c +++ b/tools/lib/bpf/libbpf.c @@ -1007,6 +1007,48 @@ static bool is_valid_st_ops_program(struct bpf_object *obj, return false; }
+/* For each struct_ops program P, referenced from some struct_ops map M, + * enable P.autoload if there are Ms for which M.autocreate is true, + * disable P.autoload if for all Ms M.autocreate is false. + * Don't change P.autoload for programs that are not referenced from any maps. + */ +static int bpf_object_adjust_struct_ops_autoload(struct bpf_object *obj) +{ + struct bpf_program *prog, *slot_prog; + struct bpf_map *map; + int i, j, k, vlen; + + for (i = 0; i < obj->nr_programs; ++i) { + int should_load = false; + int use_cnt = 0; + + prog = &obj->programs[i]; + if (prog->type != BPF_PROG_TYPE_STRUCT_OPS) + continue; + + for (j = 0; j < obj->nr_maps; ++j) { + map = &obj->maps[j]; + if (!bpf_map__is_struct_ops(map)) + continue; + + vlen = btf_vlen(map->st_ops->type); + for (k = 0; k < vlen; ++k) { + slot_prog = map->st_ops->progs[k]; + if (prog != slot_prog) + continue; + + use_cnt++; + if (map->autocreate) + should_load = true; + } + } + if (use_cnt) + prog->autoload = should_load; + } + + return 0; +} + /* Init the map's fields that depend on kern_btf */ static int bpf_map__init_kern_struct_ops(struct bpf_map *map) { @@ -8003,6 +8045,7 @@ static int bpf_object_load(struct bpf_object *obj, int extra_log_level, const ch err = err ? : bpf_object__sanitize_and_load_btf(obj); err = err ? : bpf_object__sanitize_maps(obj); err = err ? : bpf_object__init_kern_struct_ops_maps(obj); + err = err ? : bpf_object_adjust_struct_ops_autoload(obj); err = err ? : bpf_object__relocate(obj, obj->btf_custom_path ? : target_btf_path); err = err ? : bpf_object__create_maps(obj); err = err ? : bpf_object__load_progs(obj, extra_log_level);