Tests for drivers often require a struct device to pass to other functions. While it's possible to create these with root_device_register(), or to use something like a platform device, this is both a misuse of those APIs, and can be difficult to clean up after, for example, a failed assertion.
Add some KUnit-specific functions for registering and unregistering a struct device: - kunit_device_register() - kunit_device_register_with_driver() - kunit_device_unregister()
These helpers allocate a on a 'kunit' bus which will either probe the driver passed in (kunit_device_register_with_driver), or will create a stub driver (kunit_device_register) which is cleaned up on test shutdown.
Devices are automatically unregistered on test shutdown, but can be manually unregistered earlier with kunit_device_unregister() in order to, for example, test device release code.
Signed-off-by: David Gow davidgow@google.com --- Documentation/dev-tools/kunit/usage.rst | 49 +++++++++ include/kunit/device.h | 76 ++++++++++++++ lib/kunit/Makefile | 3 +- lib/kunit/device.c | 176 ++++++++++++++++++++++++++++++++ lib/kunit/kunit-test.c | 68 +++++++++++- lib/kunit/test.c | 3 + 6 files changed, 373 insertions(+), 2 deletions(-)
diff --git a/Documentation/dev-tools/kunit/usage.rst b/Documentation/dev-tools/kunit/usage.rst index 9db12e91668e..a222a98edceb 100644 --- a/Documentation/dev-tools/kunit/usage.rst +++ b/Documentation/dev-tools/kunit/usage.rst @@ -797,3 +797,52 @@ structures as shown below: KUnit is not enabled, or if no test is running in the current task, it will do nothing. This compiles down to either a no-op or a static key check, so will have a negligible performance impact when no test is running. + +Managing Fake Devcices and Drivers +---------------------------------- + +When testing drivers or code which interacts with drivers, many functions will +require a ``struct device`` or ``struct device_driver``. In many cases, setting +up a real device is not required to test any given function, so a fake device +can be used instead. + +KUnit provides helper functions to create and manage these fake devices, which +are internally of type ``struct kunit_device``, and are attached to a special +``kunit_bus``. These devices support managed device resources (devres), as +described in Documentation/driver-api/driver-model/devres.rst + +To create a KUnit-managed ``struct device_driver``, use ``kunit_driver_create()``, +which will create a driver with the given name, on the ``kunit_bus``. This driver +will automatically be destroyed when the corresponding test finishes, but can also +be manually destroyed with ``driver_unregister()``. + +To create a fake device, use the ``kunit_device_register()``, which will create +and register a device, using a new KUnit-managed driver created with ``kunit_driver_create()``. +To provide a specific, non-KUnit-managed driver, use ``kunit_device_register_with_driver()`` +instead. Like with managed drivers, KUnit-managed fake devices are automatically +cleaned up when the test finishes, but can be manually cleaned up early with +``kunit_device_unregister()``. + +The KUnit devices should be used in preference to ``root_device_register()``, and +instead of ``platform_device_register()`` in cases where the device is not otherwise +a platform device. + +For example: + +.. code-block:: c + + #include <kunit/device.h> + + static void test_my_device(struct kunit *test) + { + struct device *fake_device; + const char *dev_managed_string; + + // Create a fake device. + fake_device = kunit_device_register(test, "my_device"); + + // Pass it to functions which need a device. + dev_managed_string = devm_kstrdup(fake_device, "Hello, World!"); + + // Everything is cleaned up automatically when the test ends. + } \ No newline at end of file diff --git a/include/kunit/device.h b/include/kunit/device.h new file mode 100644 index 000000000000..fd2193bc55f1 --- /dev/null +++ b/include/kunit/device.h @@ -0,0 +1,76 @@ +/* SPDX-License-Identifier: GPL-2.0 */ +/* + * KUnit basic device implementation + * + * Helpers for creating and managing fake devices for KUnit tests. + * + * Copyright (C) 2023, Google LLC. + * Author: David Gow davidgow@google.com + */ + +#ifndef _KUNIT_DEVICE_H +#define _KUNIT_DEVICE_H + +#if IS_ENABLED(CONFIG_KUNIT) + +#include <kunit/test.h> + +struct kunit_device; +struct device; +struct device_driver; + +// For internal use only -- registers the kunit_bus. +int kunit_bus_init(void); + +/** + * kunit_driver_create() - Create a struct device_driver attached to the kunit_bus + * @test: The test context object. + * @name: The name to give the created driver. + * + * Creates a struct device_driver attached to the kunit_bus, with the name @name. + * This driver will automatically be cleaned up on test exit. + */ +struct device_driver *kunit_driver_create(struct kunit *test, const char *name); + +/** + * kunit_device_register() - Create a struct device for use in KUnit tests + * @test: The test context object. + * @name: The name to give the created device. + * + * Creates a struct kunit_device (which is a struct device) with the given name, + * and a corresponding driver. The device and driver will be cleaned up on test + * exit, or when kunit_device_unregister is called. See also + * kunit_device_register_with_driver, if you wish to provide your own + * struct device_driver. + */ +struct device *kunit_device_register(struct kunit *test, const char *name); + +/** + * kunit_device_register_with_driver() - Create a struct device for use in KUnit tests + * @test: The test context object. + * @name: The name to give the created device. + * @drv: The struct device_driver to associate with the device. + * + * Creates a struct kunit_device (which is a struct device) with the given + * name, and driver. The device will be cleaned up on test exit, or when + * kunit_device_unregister is called. See also kunit_device_register, if you + * wish KUnit to create and manage a driver for you + */ +struct device *kunit_device_register_with_driver(struct kunit *test, + const char *name, + struct device_driver *drv); + +/** + * kunit_device_unregister() - Unregister a KUnit-managed device + * @test: The test context object which created the device + * @dev: The device. + * + * Unregisters and destroys a struct device which was created with + * kunit_device_register or kunit_device_register_with_driver. If KUnit created + * a driver, cleans it up as well. + */ +void kunit_device_unregister(struct kunit *test, struct device *dev); + +#endif + +#endif diff --git a/lib/kunit/Makefile b/lib/kunit/Makefile index 46f75f23dfe4..309659a32a78 100644 --- a/lib/kunit/Makefile +++ b/lib/kunit/Makefile @@ -7,7 +7,8 @@ kunit-objs += test.o \ assert.o \ try-catch.o \ executor.o \ - attributes.o + attributes.o \ + device.o
ifeq ($(CONFIG_KUNIT_DEBUGFS),y) kunit-objs += debugfs.o diff --git a/lib/kunit/device.c b/lib/kunit/device.c new file mode 100644 index 000000000000..93ace1a2297d --- /dev/null +++ b/lib/kunit/device.c @@ -0,0 +1,176 @@ +// SPDX-License-Identifier: GPL-2.0 +/* + * KUnit basic device implementation + * + * Implementation of struct kunit_device helpers. + * + * Copyright (C) 2023, Google LLC. + * Author: David Gow davidgow@google.com + */ + +#include <linux/device.h> + +#include <kunit/test.h> +#include <kunit/device.h> +#include <kunit/resource.h> + + +/* Wrappers for use with kunit_add_action() */ +KUNIT_DEFINE_ACTION_WRAPPER(device_unregister_wrapper, device_unregister, struct device *); +KUNIT_DEFINE_ACTION_WRAPPER(driver_unregister_wrapper, driver_unregister, struct device_driver *); + +static struct device kunit_bus = { + .init_name = "kunit" +}; + +/* A device owned by a KUnit test. */ +struct kunit_device { + struct device dev; + struct kunit *owner; + /* Force binding to a specific driver. */ + struct device_driver *driver; + /* The driver is managed by KUnit and unique to this device. */ + bool cleanup_driver; +}; + +static inline struct kunit_device *to_kunit_device(struct device *d) +{ + return container_of(d, struct kunit_device, dev); +} + +static int kunit_bus_match(struct device *dev, struct device_driver *driver) +{ + struct kunit_device *kunit_dev = to_kunit_device(dev); + + if (kunit_dev->driver == driver) + return 1; + + return 0; +} + +static struct bus_type kunit_bus_type = { + .name = "kunit", + .match = kunit_bus_match +}; + +int kunit_bus_init(void) +{ + int error; + + error = bus_register(&kunit_bus_type); + if (!error) { + error = device_register(&kunit_bus); + if (error) + bus_unregister(&kunit_bus_type); + } + return error; +} +late_initcall(kunit_bus_init); + +static void kunit_device_release(struct device *d) +{ + kfree(to_kunit_device(d)); +} + +struct device_driver *kunit_driver_create(struct kunit *test, const char *name) +{ + struct device_driver *driver; + int err = -ENOMEM; + + driver = kunit_kzalloc(test, sizeof(*driver), GFP_KERNEL); + + if (!driver) + return ERR_PTR(err); + + driver->name = name; + driver->bus = &kunit_bus_type; + driver->owner = THIS_MODULE; + + err = driver_register(driver); + if (err) { + kunit_kfree(test, driver); + return ERR_PTR(err); + } + + kunit_add_action(test, driver_unregister_wrapper, driver); + return driver; +} +EXPORT_SYMBOL_GPL(kunit_driver_create); + +struct kunit_device *__kunit_device_register_internal(struct kunit *test, + const char *name, + struct device_driver *drv) +{ + struct kunit_device *kunit_dev; + int err = -ENOMEM; + + kunit_dev = kzalloc(sizeof(struct kunit_device), GFP_KERNEL); + if (!kunit_dev) + return ERR_PTR(err); + + kunit_dev->owner = test; + + err = dev_set_name(&kunit_dev->dev, "%s.%s", test->name, name); + if (err) { + kfree(kunit_dev); + return ERR_PTR(err); + } + + /* Set the expected driver pointer, so we match. */ + kunit_dev->driver = drv; + + kunit_dev->dev.release = kunit_device_release; + kunit_dev->dev.bus = &kunit_bus_type; + kunit_dev->dev.parent = &kunit_bus; + + err = device_register(&kunit_dev->dev); + if (err) { + put_device(&kunit_dev->dev); + return ERR_PTR(err); + } + + kunit_add_action(test, device_unregister_wrapper, &kunit_dev->dev); + + return kunit_dev; +} + +struct device *kunit_device_register_with_driver(struct kunit *test, + const char *name, + struct device_driver *drv) +{ + struct kunit_device *kunit_dev = __kunit_device_register_internal(test, name, drv); + + if (IS_ERR_OR_NULL(kunit_dev)) + return (struct device *)kunit_dev; /* This is an error or NULL, so is compatible */ + + return &kunit_dev->dev; +} +EXPORT_SYMBOL_GPL(kunit_device_register_with_driver); + +struct device *kunit_device_register(struct kunit *test, const char *name) +{ + struct device_driver *drv = kunit_driver_create(test, name); + struct kunit_device *dev; + + KUNIT_ASSERT_NOT_ERR_OR_NULL(test, drv); + + dev = __kunit_device_register_internal(test, name, drv); + KUNIT_ASSERT_NOT_ERR_OR_NULL(test, dev); + + dev->cleanup_driver = true; + + return (struct device *)dev; +} +EXPORT_SYMBOL_GPL(kunit_device_register); + +void kunit_device_unregister(struct kunit *test, struct device *dev) +{ + bool cleanup_driver = ((struct kunit_device *)dev)->cleanup_driver; + struct device_driver *driver = ((struct kunit_device *)dev)->driver; + + kunit_release_action(test, device_unregister_wrapper, dev); + if (cleanup_driver) + kunit_release_action(test, driver_unregister_wrapper, driver); +} +EXPORT_SYMBOL_GPL(kunit_device_unregister); + diff --git a/lib/kunit/kunit-test.c b/lib/kunit/kunit-test.c index 3e9c5192d095..a4007158bf36 100644 --- a/lib/kunit/kunit-test.c +++ b/lib/kunit/kunit-test.c @@ -8,6 +8,9 @@ #include <kunit/test.h> #include <kunit/test-bug.h>
+#include <linux/device.h> +#include <kunit/device.h> + #include "string-stream.h" #include "try-catch-impl.h"
@@ -687,6 +690,69 @@ static struct kunit_case kunit_current_test_cases[] = { {} };
+static void test_dev_action(void *priv) +{ + *(void **)priv = (void *)1; +} + +static void kunit_device_test(struct kunit *test) +{ + struct device *test_device; + + test_device = kunit_device_register(test, "my_device"); + + KUNIT_ASSERT_NOT_NULL(test, test_device); + + // Add an action to verify cleanup. + devm_add_action(test_device, test_dev_action, &test->priv); + + KUNIT_EXPECT_PTR_EQ(test, test->priv, (void *)0); + + kunit_device_unregister(test, test_device); + + KUNIT_EXPECT_PTR_EQ(test, test->priv, (void *)1); +} + +static void kunit_device_driver_test(struct kunit *test) +{ + struct device_driver *test_driver; + struct device *test_device; + + test_driver = kunit_driver_create(test, "my_driver"); + + KUNIT_ASSERT_NOT_NULL(test, test_driver); + + test_device = kunit_device_register_with_driver(test, "my_device", test_driver); + + KUNIT_ASSERT_NOT_NULL(test, test_device); + + // Add an action to verify cleanup. + devm_add_action(test_device, test_dev_action, &test->priv); + + KUNIT_EXPECT_PTR_EQ(test, test->priv, (void *)0); + + kunit_device_unregister(test, test_device); + test_device = NULL; + + // The driver should not automatically be destroyed by + // kunit_device_unregister, so we can re-use it. + test_device = kunit_device_register_with_driver(test, "my_device", test_driver); + KUNIT_ASSERT_NOT_NULL(test, test_device); + + // Everything is automatically freed here. +} + +static struct kunit_case kunit_device_test_cases[] = { + KUNIT_CASE(kunit_device_test), + KUNIT_CASE(kunit_device_driver_test), + {} +}; + +static struct kunit_suite kunit_device_test_suite = { + .name = "kunit_device", + .test_cases = kunit_device_test_cases, +}; + static struct kunit_suite kunit_current_test_suite = { .name = "kunit_current", .test_cases = kunit_current_test_cases, @@ -694,6 +760,6 @@ static struct kunit_suite kunit_current_test_suite = {
kunit_test_suites(&kunit_try_catch_test_suite, &kunit_resource_test_suite, &kunit_log_test_suite, &kunit_status_test_suite, - &kunit_current_test_suite); + &kunit_current_test_suite, &kunit_device_test_suite);
MODULE_LICENSE("GPL v2"); diff --git a/lib/kunit/test.c b/lib/kunit/test.c index 0308865194bb..144c8e7be197 100644 --- a/lib/kunit/test.c +++ b/lib/kunit/test.c @@ -10,6 +10,7 @@ #include <kunit/test.h> #include <kunit/test-bug.h> #include <kunit/attributes.h> +#include <kunit/device.h> #include <linux/kernel.h> #include <linux/module.h> #include <linux/moduleparam.h> @@ -840,6 +841,8 @@ static int __init kunit_init(void) kunit_install_hooks();
kunit_debugfs_init(); + + kunit_bus_init(); #ifdef CONFIG_MODULES return register_module_notifier(&kunit_mod_nb); #else