bpf: libbpf: remove map name retry from bpf_create_map_xattr

Instead, check for a newly created caps.name bpf_object capability.
If kernel doesn't support names, don't specify the attribute.

See commit 23499442 ("bpf: libbpf: retry map creation without
the name") for rationale.
Signed-off-by: Stanislav Fomichev <sdf@google.com>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>

tools/lib/bpf/bpf.c

@@ -69,7 +69,6 @@ int bpf_create_map_xattr(const struct bpf_create_map_attr *create_attr)
 {
 	__u32 name_len = create_attr->name ? strlen(create_attr->name) : 0;
 	union bpf_attr attr;
-	int ret;
 
 	memset(&attr, '\0', sizeof(attr));
 
@@ -87,15 +86,7 @@ int bpf_create_map_xattr(const struct bpf_create_map_attr *create_attr)
 	attr.map_ifindex = create_attr->map_ifindex;
 	attr.inner_map_fd = create_attr->inner_map_fd;
 
-	ret = sys_bpf(BPF_MAP_CREATE, &attr, sizeof(attr));
-	if (ret < 0 && errno == EINVAL && create_attr->name) {
-		/* Retry the same syscall, but without the name.
-		 * Pre v4.14 kernels don't support map names.
-		 */
-		memset(attr.map_name, 0, sizeof(attr.map_name));
-		return sys_bpf(BPF_MAP_CREATE, &attr, sizeof(attr));
-	}
-	return ret;
+	return sys_bpf(BPF_MAP_CREATE, &attr, sizeof(attr));
 }
 
 int bpf_create_map_node(enum bpf_map_type map_type, const char *name,

tools/lib/bpf/libbpf.c

@@ -1211,7 +1211,8 @@ bpf_object__create_maps(struct bpf_object *obj)
 			continue;
 		}
 
-		create_attr.name = map->name;
+		if (obj->caps.name)
+			create_attr.name = map->name;
 		create_attr.map_ifindex = map->map_ifindex;
 		create_attr.map_type = def->type;
 		create_attr.map_flags = def->map_flags;