bpf: Reenable bpf_refcount_acquire

Now that all reported issues are fixed, bpf_refcount_acquire can be
turned back on. Also reenable all bpf_refcount-related tests which were
disabled.

This a revert of:
* commit f3514a5d6740 ("selftests/bpf: Disable newly-added 'owner' field test until refcount re-enabled")
* commit 7deca5eae833 ("bpf: Disable bpf_refcount_acquire kfunc calls until race conditions are fixed")

Signed-off-by: Dave Marchevsky <[e-mail]>
Acked-by: Yonghong Song <[e-mail]>
Link: https://lore.kernel.org/r/[e-mail]
Signed-off-by: Alexei Starovoitov <[e-mail]>

kernel/bpf/verifier.c

···
 				verbose(env, "arg#%d doesn't point to a type with bpf_refcount field\n", i);
 				return -EINVAL;
 			}
-			if (rec->refcount_off >= 0) {
-				verbose(env, "bpf_refcount_acquire calls are disabled for now\n");
-				return -EINVAL;
-			}
+
 			meta->arg_btf = reg->btf;
 			meta->arg_btf_id = reg->btf_id;
 			break;

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

···
 
 void test_refcounted_kptr(void)
 {
+	RUN_TESTS(refcounted_kptr);
 }
 
 void test_refcounted_kptr_fail(void)
 {
+	RUN_TESTS(refcounted_kptr_fail);
 }
 
 void test_refcounted_kptr_wrong_owner(void)
 {
+	LIBBPF_OPTS(bpf_test_run_opts, opts,
+		    .data_in = &pkt_v4,
+		    .data_size_in = sizeof(pkt_v4),
+		    .repeat = 1,
+	);
+	struct refcounted_kptr *skel;
+	int ret;
+
+	skel = refcounted_kptr__open_and_load();
+	if (!ASSERT_OK_PTR(skel, "refcounted_kptr__open_and_load"))
+		return;
+
+	ret = bpf_prog_test_run_opts(bpf_program__fd(skel->progs.rbtree_wrong_owner_remove_fail_a1), &opts);
+	ASSERT_OK(ret, "rbtree_wrong_owner_remove_fail_a1");
+	ASSERT_OK(opts.retval, "rbtree_wrong_owner_remove_fail_a1 retval");
+
+	ret = bpf_prog_test_run_opts(bpf_program__fd(skel->progs.rbtree_wrong_owner_remove_fail_b), &opts);
+	ASSERT_OK(ret, "rbtree_wrong_owner_remove_fail_b");
+	ASSERT_OK(opts.retval, "rbtree_wrong_owner_remove_fail_b retval");
+
+	ret = bpf_prog_test_run_opts(bpf_program__fd(skel->progs.rbtree_wrong_owner_remove_fail_a2), &opts);
+	ASSERT_OK(ret, "rbtree_wrong_owner_remove_fail_a2");
+	ASSERT_OK(opts.retval, "rbtree_wrong_owner_remove_fail_a2 retval");
+	refcounted_kptr__destroy(skel);
 }