bpf: Remove attach_type in sockmap_link

Use attach_type in bpf_link, and remove it in sockmap_link.

Signed-off-by: Tao Chen <[e-mail]>
Signed-off-by: Andrii Nakryiko <[e-mail]>
Acked-by: Daniel Borkmann <[e-mail]>
Acked-by: Jiri Olsa <[e-mail]>
Link: https://lore.kernel.org/bpf/[e-mail]

net/core/sock_map.c

···
 struct sockmap_link {
 	struct bpf_link link;
 	struct bpf_map *map;
-	enum bpf_attach_type attach_type;
 };
 
 static void sock_map_link_release(struct bpf_link *link)
···
 		goto out;
 
 	WARN_ON_ONCE(sock_map_prog_update(sockmap_link->map, NULL, link->prog, link,
-					  sockmap_link->attach_type));
+					  link->attach_type));
 
 	bpf_map_put_with_uref(sockmap_link->map);
 	sockmap_link->map = NULL;
···
 	}
 
 	ret = sock_map_prog_link_lookup(sockmap_link->map, &pprog, &plink,
-					sockmap_link->attach_type);
+					link->attach_type);
 	if (ret)
 		goto out;
 
···
 	u32 map_id = sock_map_link_get_map_id(sockmap_link);
 
 	info->sockmap.map_id = map_id;
-	info->sockmap.attach_type = sockmap_link->attach_type;
+	info->sockmap.attach_type = link->attach_type;
 	return 0;
 }
 
···
 	u32 map_id = sock_map_link_get_map_id(sockmap_link);
 
 	seq_printf(seq, "map_id:\t%u\n", map_id);
-	seq_printf(seq, "attach_type:\t%u\n", sockmap_link->attach_type);
+	seq_printf(seq, "attach_type:\t%u\n", link->attach_type);
 }
 
 static const struct bpf_link_ops sock_map_link_ops = {
···
 	bpf_link_init(&sockmap_link->link, BPF_LINK_TYPE_SOCKMAP, &sock_map_link_ops, prog,
 		      attach_type);
 	sockmap_link->map = map;
-	sockmap_link->attach_type = attach_type;
 
 	ret = bpf_link_prime(&sockmap_link->link, &link_primer);
 	if (ret) {