6.6-stable review patch. If anyone has any objections, please let me know.
------------------
From: Eduard Zingerman <eddyz87@xxxxxxxxx>
[ 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@xxxxxxxxx>
Signed-off-by: Andrii Nakryiko <andrii@xxxxxxxxxx>
Link: https://lore.kernel.org/bpf/20240306104529.6453-9-eddyz87@xxxxxxxxx
Stable-dep-of: 04a94133f1b3 ("libbpf: Don't take direct pointers into BTF data from st_ops")
Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx>
---
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);
--
2.43.0
