selftests/bpf: Adapt cgroup effective query uapi change

The attach flags is meaningless for effective query and
its value will always be set as 0 during effective query.
Root cg's effective progs is always its attached progs,
so we use non-effective query to get its progs count and
attach flags. And we don't need the remain attach flags
check.

Fixes: b79c9fc9551b ("bpf: implement BPF_PROG_QUERY for BPF_LSM_CGROUP")
Signed-off-by: Pu Lehui <[e-mail]>
Link: https://lore.kernel.org/r/[e-mail]
Signed-off-by: Martin KaFai Lau <[e-mail]>

tools/testing/selftests/bpf/prog_tests/cgroup_link.c

···
 
 	ping_and_check(cg_nr, 0);
 
-	/* query the number of effective progs and attach flags in root cg */
+	/* query the number of attached progs and attach flags in root cg */
 	err = bpf_prog_query(cgs[0].fd, BPF_CGROUP_INET_EGRESS,
-			     BPF_F_QUERY_EFFECTIVE, &attach_flags, NULL,
-			     &prog_cnt);
+			     0, &attach_flags, NULL, &prog_cnt);
 	CHECK_FAIL(err);
 	CHECK_FAIL(attach_flags != BPF_F_ALLOW_MULTI);
 	if (CHECK(prog_cnt != 1, "effect_cnt", "exp %d, got %d\n", 1, prog_cnt))
···
 			     BPF_F_QUERY_EFFECTIVE, NULL, NULL,
 			     &prog_cnt);
 	CHECK_FAIL(err);
-	CHECK_FAIL(attach_flags != BPF_F_ALLOW_MULTI);
 	if (CHECK(prog_cnt != cg_nr, "effect_cnt", "exp %d, got %d\n",
 		  cg_nr, prog_cnt))
 		goto cleanup;
 
 	/* query the effective prog IDs in last cg */
 	err = bpf_prog_query(cgs[last_cg].fd, BPF_CGROUP_INET_EGRESS,
-			     BPF_F_QUERY_EFFECTIVE, &attach_flags,
-			     prog_ids, &prog_cnt);
+			     BPF_F_QUERY_EFFECTIVE, NULL, prog_ids,
+			     &prog_cnt);
 	CHECK_FAIL(err);
-	CHECK_FAIL(attach_flags != BPF_F_ALLOW_MULTI);
 	if (CHECK(prog_cnt != cg_nr, "effect_cnt", "exp %d, got %d\n",
 		  cg_nr, prog_cnt))
 		goto cleanup;