[LTP] [PATCH] device-drivers/acpi: skip the test if ACPI is disabled

[Stanislav Kholmanskikh]

Calling functions such as acpi_get_devices() on a system with ACPI
disabled (for example, a virtual machine) leads to a kernel panic.

Earlier there was a related discussion on linux-acpi:

https://www.spinics.net/lists/linux-acpi/msg79419.html

and they came to the conclusion that the caller of the API should
check if ACPI is enabled, i.e. the test needs an update.

Suggested-by: Rob Gardner <rob.gardner@oracle.com>
Signed-off-by: Stanislav Kholmanskikh <stanislav.kholmanskikh@oracle.com>
---
 testcases/kernel/device-drivers/acpi/ltp_acpi.c    |    7 +++++++
 .../kernel/device-drivers/acpi/ltp_acpi_cmds.c     |   15 +++++++++++++++
 2 files changed, 22 insertions(+), 0 deletions(-)

diff --git a/testcases/kernel/device-drivers/acpi/ltp_acpi.c b/testcases/kernel/device-drivers/acpi/ltp_acpi.c
index d20d38f..f2dc6a4 100644
--- a/testcases/kernel/device-drivers/acpi/ltp_acpi.c
+++ b/testcases/kernel/device-drivers/acpi/ltp_acpi.c
@@ -34,6 +34,7 @@ static const char dev_result[]	= "/sys/devices/" ACPI_TEST_NAME "/result";
 static const char dev_path[]	= "/sys/devices/" ACPI_TEST_NAME "/path";
 static const char dev_str[]	= "/sys/devices/" ACPI_TEST_NAME "/str";
 static const char dev_tcase[]	= "/sys/devices/" ACPI_TEST_NAME "/tcase";
+static const char dev_acpi_disabled[] = "/sys/devices/" ACPI_TEST_NAME "/acpi_disabled";
 static const char module_name[]	= "ltp_acpi_cmds.ko";
 static int module_loaded;
 
@@ -141,6 +142,8 @@ static void test_run(void)
 
 int main(int argc, char *argv[])
 {
+	int acpi_disabled;
+
 	tst_parse_opts(argc, argv, NULL, NULL);
 
 	tst_require_root();
@@ -155,6 +158,10 @@ int main(int argc, char *argv[])
 	tst_module_load(NULL, module_name, NULL);
 	module_loaded = 1;
 
+	SAFE_FILE_SCANF(cleanup, dev_acpi_disabled, "%d", &acpi_disabled);
+	if (acpi_disabled)
+		tst_brkm(TCONF, cleanup, "ACPI is disabled on the system");
+
 	test_run();
 
 	cleanup();
diff --git a/testcases/kernel/device-drivers/acpi/ltp_acpi_cmds.c b/testcases/kernel/device-drivers/acpi/ltp_acpi_cmds.c
index 419eb6a..6e8f051 100644
--- a/testcases/kernel/device-drivers/acpi/ltp_acpi_cmds.c
+++ b/testcases/kernel/device-drivers/acpi/ltp_acpi_cmds.c
@@ -537,6 +537,13 @@ static ssize_t sys_path(struct device *dev,
 }
 static DEVICE_ATTR(path, S_IRUSR, sys_path, NULL);
 
+static ssize_t sys_acpi_disabled(struct device *dev,
+				    struct device_attribute *attr, char *buf)
+{
+	return scnprintf(buf, PAGE_SIZE, "%d", acpi_disabled);
+}
+static DEVICE_ATTR(acpi_disabled, S_IRUSR, sys_acpi_disabled, NULL);
+
 static ssize_t sys_tcase(struct device *dev,
 	struct device_attribute *attr,  const char *buf, size_t count)
 {
@@ -616,8 +623,16 @@ int init_module(void)
 		goto err4;
 	}
 
+	err = device_create_file(&tdev, &dev_attr_acpi_disabled);
+	if (err) {
+		prk_err("Can't create sysfs file 'acpi_disabled'");
+		goto err5;
+	}
+
 	return 0;
 
+err5:
+	device_remove_file(&tdev, &dev_attr_path);
 err4:
 	device_remove_file(&tdev, &dev_attr_tcase);
 err3:
-- 
1.7.1