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drivers: base: Add basic devm tests for root devices

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The root devices show some odd behaviours compared to regular "bus" devices
that have been probed through the usual mechanism, so let's create kunit
tests to exercise those paths and odd cases.

It's not clear whether root devices are even allowed to use device
managed resources, but the fact that it works in some cases but not
others like shown in that test suite shouldn't happen either way: we
want to make it consistent and documented.

These tests will (after the following patches) ensure that consistency
and effectively document that it's allowed.

If it ever turns out to be a bad idea, we can always roll back and
modify the tests then.

Reviewed-by: David Gow <davidgow@google.com>
Signed-off-by: Maxime Ripard <mripard@kernel.org>
Link: https://lore.kernel.org/r/20230720-kunit-devm-inconsistencies-test-v3-1-6aa7e074f373@kernel.org
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
This commit is contained in:
Maxime Ripard 2023-07-20 14:45:07 +02:00 committed by Greg Kroah-Hartman
parent 0559f63057
commit 06188bc80c
4 changed files with 118 additions and 0 deletions
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2
drivers/base/test/.kunitconfig Normal file
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@ -0,0 +1,2 @@
CONFIG_KUNIT=y
CONFIG_DM_KUNIT_TEST=y

4
drivers/base/test/Kconfig
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@ -9,6 +9,10 @@ config TEST_ASYNC_DRIVER_PROBE
If unsure say N.
config DM_KUNIT_TEST
tristate "KUnit Tests for the device model" if !KUNIT_ALL_TESTS
depends on KUNIT
config DRIVER_PE_KUNIT_TEST
bool "KUnit Tests for property entry API" if !KUNIT_ALL_TESTS
depends on KUNIT=y

2
drivers/base/test/Makefile
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@ -1,5 +1,7 @@
# SPDX-License-Identifier: GPL-2.0
obj-$(CONFIG_TEST_ASYNC_DRIVER_PROBE) += test_async_driver_probe.o
obj-$(CONFIG_DM_KUNIT_TEST) += root-device-test.o
obj-$(CONFIG_DRIVER_PE_KUNIT_TEST) += property-entry-test.o
CFLAGS_property-entry-test.o += $(DISABLE_STRUCTLEAK_PLUGIN)

110
drivers/base/test/root-device-test.c Normal file
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@ -0,0 +1,110 @@
// SPDX-License-Identifier: GPL-2.0
// Copyright 2023 Maxime Ripard <mripard@kernel.org>
#include <kunit/resource.h>
#include <linux/device.h>
#define DEVICE_NAME "test"
struct test_priv {
bool probe_done;
bool release_done;
wait_queue_head_t release_wq;
struct device *dev;
};
static int root_device_devm_init(struct kunit *test)
{
struct test_priv *priv;
priv = kunit_kzalloc(test, sizeof(*priv), GFP_KERNEL);
KUNIT_ASSERT_NOT_ERR_OR_NULL(test, priv);
init_waitqueue_head(&priv->release_wq);
test->priv = priv;
return 0;
}
static void devm_device_action(void *ptr)
{
struct test_priv *priv = ptr;
priv->release_done = true;
wake_up_interruptible(&priv->release_wq);
}
#define RELEASE_TIMEOUT_MS 100
/*
* Tests that a bus-less, non-probed device will run its device-managed
* actions when unregistered.
*/
static void root_device_devm_register_unregister_test(struct kunit *test)
{
struct test_priv *priv = test->priv;
int ret;
priv->dev = root_device_register(DEVICE_NAME);
KUNIT_ASSERT_NOT_ERR_OR_NULL(test, priv->dev);
ret = devm_add_action_or_reset(priv->dev, devm_device_action, priv);
KUNIT_ASSERT_EQ(test, ret, 0);
root_device_unregister(priv->dev);
ret = wait_event_interruptible_timeout(priv->release_wq, priv->release_done,
msecs_to_jiffies(RELEASE_TIMEOUT_MS));
KUNIT_EXPECT_GT(test, ret, 0);
}
static void devm_put_device_action(void *ptr)
{
struct test_priv *priv = ptr;
put_device(priv->dev);
priv->release_done = true;
wake_up_interruptible(&priv->release_wq);
}
/*
* Tests that a bus-less, non-probed device will run its device-managed
* actions when unregistered, even if someone still holds a reference to
* it.
*/
static void root_device_devm_register_get_unregister_with_devm_test(struct kunit *test)
{
struct test_priv *priv = test->priv;
int ret;
kunit_skip(test, "This needs to be fixed in the core.");
priv->dev = root_device_register(DEVICE_NAME);
KUNIT_ASSERT_NOT_ERR_OR_NULL(test, priv->dev);
get_device(priv->dev);
ret = devm_add_action_or_reset(priv->dev, devm_put_device_action, priv);
KUNIT_ASSERT_EQ(test, ret, 0);
root_device_unregister(priv->dev);
ret = wait_event_interruptible_timeout(priv->release_wq, priv->release_done,
msecs_to_jiffies(RELEASE_TIMEOUT_MS));
KUNIT_EXPECT_GT(test, ret, 0);
}
static struct kunit_case root_device_devm_tests[] = {
KUNIT_CASE(root_device_devm_register_unregister_test),
KUNIT_CASE(root_device_devm_register_get_unregister_with_devm_test),
{}
};
static struct kunit_suite root_device_devm_test_suite = {
.name = "root-device-devm",
.init = root_device_devm_init,
.test_cases = root_device_devm_tests,
};
kunit_test_suite(root_device_devm_test_suite);