bpf: Remove attach_type in bpf_cgroup_link

Use attach_type in bpf_link, and remove it in bpf_cgroup_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]

include/linux/bpf-cgroup.h

···
 struct bpf_cgroup_link {
 	struct bpf_link link;
 	struct cgroup *cgroup;
-	enum bpf_attach_type type;
 };
 
 struct bpf_prog_list {

kernel/bpf/cgroup.c

···
 	struct hlist_head *progs;
 	bool found = false;
 
-	atype = bpf_cgroup_atype_find(link->type, new_prog->aux->attach_btf_id);
+	atype = bpf_cgroup_atype_find(link->link.attach_type, new_prog->aux->attach_btf_id);
 	if (atype < 0)
 		return -EINVAL;
 
···
 	}
 
 	WARN_ON(__cgroup_bpf_detach(cg_link->cgroup, NULL, cg_link,
-				    cg_link->type, 0));
-	if (cg_link->type == BPF_LSM_CGROUP)
+				    link->attach_type, 0));
+	if (link->attach_type == BPF_LSM_CGROUP)
 		bpf_trampoline_unlink_cgroup_shim(cg_link->link.prog);
 
 	cg = cg_link->cgroup;
···
 		   "cgroup_id:\t%llu\n"
 		   "attach_type:\t%d\n",
 		   cg_id,
-		   cg_link->type);
+		   link->attach_type);
 }
 
 static int bpf_cgroup_link_fill_link_info(const struct bpf_link *link,
···
 	cgroup_unlock();
 
 	info->cgroup.cgroup_id = cg_id;
-	info->cgroup.attach_type = cg_link->type;
+	info->cgroup.attach_type = link->attach_type;
 	return 0;
 }
 
···
 	bpf_link_init(&link->link, BPF_LINK_TYPE_CGROUP, &bpf_cgroup_link_lops,
 		      prog, attr->link_create.attach_type);
 	link->cgroup = cgrp;
-	link->type = attr->link_create.attach_type;
 
 	err = bpf_link_prime(&link->link, &link_primer);
 	if (err) {
···
 	}
 
 	err = cgroup_bpf_attach(cgrp, NULL, NULL, link,
-				link->type, BPF_F_ALLOW_MULTI | attr->link_create.flags,
+				link->link.attach_type, BPF_F_ALLOW_MULTI | attr->link_create.flags,
 				attr->link_create.cgroup.relative_fd,
 				attr->link_create.cgroup.expected_revision);
 	if (err) {