test_sysctl: Add an unregister sysctl test

Add a test that checks that the unregistered directory is removed from
/proc/sys/debug
Signed-off-by: Joel Granados <j.granados@samsung.com>
Signed-off-by: Luis Chamberlain <mcgrof@kernel.org>

lib/test_sysctl.c

@@ -170,12 +170,42 @@ static int test_sysctl_setup_node_tests(void)
 	return 0;
 }
 
+/* Used to test that unregister actually removes the directory */
+static struct ctl_table test_table_unregister[] = {
+	{
+		.procname	= "unregister_error",
+		.data		= &test_data.int_0001,
+		.maxlen		= sizeof(int),
+		.mode		= 0644,
+		.proc_handler	= proc_dointvec_minmax,
+	},
+	{}
+};
+
+static int test_sysctl_run_unregister_nested(void)
+{
+	struct ctl_table_header *unregister;
+
+	unregister = register_sysctl("debug/test_sysctl/unregister_error",
+				   test_table_unregister);
+	if (!unregister)
+		return -ENOMEM;
+
+	unregister_sysctl_table(unregister);
+	return 0;
+}
+
 static int __init test_sysctl_init(void)
 {
 	int err;
 
 	err = test_sysctl_setup_node_tests();
+	if (err)
+		goto out;
+
+	err = test_sysctl_run_unregister_nested();
 
+out:
 	return err;
 }
 module_init(test_sysctl_init);

tools/testing/selftests/sysctl/sysctl.sh

@@ -31,6 +31,7 @@ ALL_TESTS="$ALL_TESTS 0005:3:1:int_0003"
 ALL_TESTS="$ALL_TESTS 0006:50:1:bitmap_0001"
 ALL_TESTS="$ALL_TESTS 0007:1:1:boot_int"
 ALL_TESTS="$ALL_TESTS 0008:1:1:match_int"
+ALL_TESTS="$ALL_TESTS 0009:1:1:unregister_error"
 
 function allow_user_defaults()
 {
@@ -797,6 +798,20 @@ sysctl_test_0008()
 	return 0
 }
 
+sysctl_test_0009()
+{
+	TARGET="${SYSCTL}/$(get_test_target 0009)"
+	echo -n "Testing if $TARGET unregistered correctly ..."
+	if [ -d $TARGET ]; then
+		echo "TEST FAILED"
+		rc=1
+		test_rc
+	fi
+
+	echo "ok"
+	return 0
+}
+
 list_tests()
 {
 	echo "Test ID list:"
@@ -813,6 +828,7 @@ list_tests()
 	echo "0006 x $(get_test_count 0006) - tests proc_do_large_bitmap()"
 	echo "0007 x $(get_test_count 0007) - tests setting sysctl from kernel boot param"
 	echo "0008 x $(get_test_count 0008) - tests sysctl macro values match"
+	echo "0009 x $(get_test_count 0009) - tests sysct unregister"
 }
 
 usage()