[PATCH bpf-next v3 01/15] libbpf: allow version suffixes (___smth) for struct_ops types

[Eduard Zingerman <eddyz87@gmail.com>]

E.g. allow the following struct_ops definitions:

    struct bpf_testmod_ops___v1 { int (*test)(void); };
    struct bpf_testmod_ops___v2 { int (*test)(void); };

    SEC(".struct_ops.link")
    struct bpf_testmod_ops___v1 a = { .test = ... }
    SEC(".struct_ops.link")
    struct bpf_testmod_ops___v2 b = { .test = ... }

Where both bpf_testmod_ops__v1 and bpf_testmod_ops__v2 would be
resolved as 'struct bpf_testmod_ops' from kernel BTF.

Acked-by: David Vernet <void@manifault.com>
Signed-off-by: Eduard Zingerman <eddyz87@gmail.com>
---
 tools/lib/bpf/libbpf.c | 6 +++++-
 1 file changed, 5 insertions(+), 1 deletion(-)

diff --git a/tools/lib/bpf/libbpf.c b/tools/lib/bpf/libbpf.c
index 6c2979f1b471..e2a4c409980b 100644
--- a/tools/lib/bpf/libbpf.c
+++ b/tools/lib/bpf/libbpf.c
@@ -948,7 +948,7 @@ static int find_btf_by_prefix_kind(const struct btf *btf, const char *prefix,
 				   const char *name, __u32 kind);
 
 static int
-find_struct_ops_kern_types(struct bpf_object *obj, const char *tname,
+find_struct_ops_kern_types(struct bpf_object *obj, const char *tname_raw,
 			   struct module_btf **mod_btf,
 			   const struct btf_type **type, __u32 *type_id,
 			   const struct btf_type **vtype, __u32 *vtype_id,
@@ -958,8 +958,12 @@ find_struct_ops_kern_types(struct bpf_object *obj, const char *tname,
 	const struct btf_member *kern_data_member;
 	struct btf *btf;
 	__s32 kern_vtype_id, kern_type_id;
+	char tname[256];
 	__u32 i;
 
+	snprintf(tname, sizeof(tname), "%.*s",
+		 (int)bpf_core_essential_name_len(tname_raw), tname_raw);
+
 	kern_type_id = find_ksym_btf_id(obj, tname, BTF_KIND_STRUCT,
 					&btf, mod_btf);
 	if (kern_type_id < 0) {
-- 
2.43.0