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.

Reviewed-by: Matti Vaittinen mazziesaccount@gmail.com Reviewed-by: Maxime Ripard mripard@kernel.org Signed-off-by: David Gow davidgow@google.com --- Documentation/dev-tools/kunit/api/resource.rst | 9 ++ Documentation/dev-tools/kunit/usage.rst | 50 +++++++ include/kunit/device.h | 80 +++++++++++ lib/kunit/Makefile | 3 +- lib/kunit/device-impl.h | 17 +++ lib/kunit/device.c | 181 +++++++++++++++++++++++++ lib/kunit/kunit-test.c | 134 +++++++++++++++++- lib/kunit/test.c | 3 + 8 files changed, 475 insertions(+), 2 deletions(-)

diff --git a/Documentation/dev-tools/kunit/api/resource.rst b/Documentation/dev-tools/kunit/api/resource.rst index 0a94f831259e..ec6002a6b0db 100644 --- a/Documentation/dev-tools/kunit/api/resource.rst +++ b/Documentation/dev-tools/kunit/api/resource.rst @@ -11,3 +11,12 @@ state on a per-test basis, register custom cleanup actions, and more.

.. kernel-doc:: include/kunit/resource.h :internal: + +Managed Devices +--------------- + +Functions for using KUnit-managed struct device and struct device_driver. +Include ``kunit/device.h`` to use these. + +.. kernel-doc:: include/kunit/device.h + :internal: diff --git a/Documentation/dev-tools/kunit/usage.rst b/Documentation/dev-tools/kunit/usage.rst index 9db12e91668e..53c6f7dc8a42 100644 --- a/Documentation/dev-tools/kunit/usage.rst +++ b/Documentation/dev-tools/kunit/usage.rst @@ -797,3 +797,53 @@ 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 Devices 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"); + KUNIT_ASSERT_NOT_ERR_OR_NULL(test, fake_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..2450110ad64e --- /dev/null +++ b/include/kunit/device.h @@ -0,0 +1,80 @@ +/* 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 device; +struct device_driver; + +/** + * 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. + * + * Return: a stub struct device_driver, managed by KUnit, with the name @name. + */ +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. + * + * Return: a pointer to a struct device which will be cleaned up when the test + * exits, or an error pointer if the device could not be allocated or registered. + */ +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. + * + * Return: a pointer to a struct device which will be cleaned up when the test + * exits, or an error pointer if the device could not be allocated or registered. + */ +struct device *kunit_device_register_with_driver(struct kunit *test, + const char *name, + const 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-impl.h b/lib/kunit/device-impl.h new file mode 100644 index 000000000000..54bd55836405 --- /dev/null +++ b/lib/kunit/device-impl.h @@ -0,0 +1,17 @@ +/* SPDX-License-Identifier: GPL-2.0 */ +/* + * KUnit internal header for device helpers + * + * Header for KUnit-internal driver / bus management. + * + * Copyright (C) 2023, Google LLC. + * Author: David Gow davidgow@google.com + */ + +#ifndef _KUNIT_DEVICE_IMPL_H +#define _KUNIT_DEVICE_IMPL_H + +// For internal use only -- registers the kunit_bus. +int kunit_bus_init(void); + +#endif //_KUNIT_DEVICE_IMPL_H diff --git a/lib/kunit/device.c b/lib/kunit/device.c new file mode 100644 index 000000000000..1db4305b615a --- /dev/null +++ b/lib/kunit/device.c @@ -0,0 +1,181 @@ +// SPDX-License-Identifier: GPL-2.0 +/* + * KUnit-managed device implementation + * + * Implementation of struct kunit_device helpers for fake devices whose + * lifecycle is managed by KUnit. + * + * 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> + +#include "device-impl.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 *); + +/* The root device for the KUnit bus, parent of all kunit_devices. */ +static struct device *kunit_bus_device; + +/* A device owned by a KUnit test. */ +struct kunit_device { + struct device dev; + /* The KUnit test which owns this device. */ + struct kunit *owner; + /* If the driver is managed by KUnit and unique to this device. */ + const struct device_driver *driver; +}; + +#define to_kunit_device(d) container_of_const(d, struct kunit_device, dev) + +static struct bus_type kunit_bus_type = { + .name = "kunit", +}; + +/* Register the 'kunit_bus' used for fake devices. */ +int kunit_bus_init(void) +{ + int error; + + kunit_bus_device = root_device_register("kunit"); + if (!kunit_bus_device) + return -ENOMEM; + + error = bus_register(&kunit_bus_type); + if (error) + bus_unregister(&kunit_bus_type); + return error; +} + +/* Release a 'fake' KUnit device. */ +static void kunit_device_release(struct device *d) +{ + kfree(to_kunit_device(d)); +} + +/** + * Create and register a KUnit-managed struct device_driver on the kunit_bus. + * Returns an error pointer on failure. + */ +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); + +/* Helper which creates a kunit_device, attaches it to the kunit_bus*/ +static struct kunit_device *kunit_device_register_internal(struct kunit *test, + const char *name, + const struct device_driver *drv) +{ + struct kunit_device *kunit_dev; + int err = -ENOMEM; + + kunit_dev = kzalloc(sizeof(*kunit_dev), 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); + } + + kunit_dev->dev.release = kunit_device_release; + kunit_dev->dev.bus = &kunit_bus_type; + kunit_dev->dev.parent = kunit_bus_device; + + 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; +} + +/** + * Create and register a new KUnit-managed device, using the user-supplied device_driver. + * On failure, returns an error pointer. + */ +struct device *kunit_device_register_with_driver(struct kunit *test, + const char *name, + const struct device_driver *drv) +{ + struct kunit_device *kunit_dev = kunit_device_register_internal(test, name, drv); + + if (IS_ERR_OR_NULL(kunit_dev)) + return ERR_CAST(kunit_dev); + + return &kunit_dev->dev; +} +EXPORT_SYMBOL_GPL(kunit_device_register_with_driver); + +/** + * Create and register a new KUnit-managed device, including a matching device_driver. + * On failure, returns an error pointer. + */ +struct device *kunit_device_register(struct kunit *test, const char *name) +{ + struct device_driver *drv; + struct kunit_device *dev; + + drv = kunit_driver_create(test, name); + if (IS_ERR(drv)) + return ERR_CAST(drv); + + dev = kunit_device_register_internal(test, name, drv); + if (IS_ERR(dev)) { + kunit_release_action(test, driver_unregister_wrapper, (void *)drv); + return ERR_CAST(dev); + } + + /* Request the driver be freed. */ + dev->driver = drv; + + + return &dev->dev; +} +EXPORT_SYMBOL_GPL(kunit_device_register); + +/* Unregisters a KUnit-managed device early (including the driver, if automatically created). */ +void kunit_device_unregister(struct kunit *test, struct device *dev) +{ + const struct device_driver *driver = to_kunit_device(dev)->driver; + + kunit_release_action(test, device_unregister_wrapper, dev); + if (driver) + kunit_release_action(test, driver_unregister_wrapper, (void *)driver); +} +EXPORT_SYMBOL_GPL(kunit_device_unregister); + diff --git a/lib/kunit/kunit-test.c b/lib/kunit/kunit-test.c index ee6927c60979..c4259d910356 100644 --- a/lib/kunit/kunit-test.c +++ b/lib/kunit/kunit-test.c @@ -5,9 +5,13 @@ * Copyright (C) 2019, Google LLC. * Author: Brendan Higgins brendanhiggins@google.com */ +#include "linux/gfp_types.h" #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 +691,134 @@ 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; + long action_was_run = 0; + + test_device = kunit_device_register(test, "my_device"); + KUNIT_ASSERT_NOT_ERR_OR_NULL(test, test_device); + + // Add an action to verify cleanup. + devm_add_action(test_device, test_dev_action, &action_was_run); + + KUNIT_EXPECT_EQ(test, action_was_run, 0); + + kunit_device_unregister(test, test_device); + + KUNIT_EXPECT_EQ(test, action_was_run, 1); +} + +static void kunit_device_cleanup_test(struct kunit *test) +{ + struct device *test_device; + long action_was_run = 0; + + 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, &action_was_run); + + KUNIT_EXPECT_EQ(test, action_was_run, 0); + + /* Force KUnit to run cleanup early. */ + kunit_cleanup(test); + + KUNIT_EXPECT_EQ(test, action_was_run, 1); +} + +struct driver_test_state { + bool driver_device_probed; + bool driver_device_removed; + long action_was_run; +}; + +static int driver_probe_hook(struct device *dev) +{ + struct kunit *test = kunit_get_current_test(); + struct driver_test_state *state = (struct driver_test_state *)test->priv; + + state->driver_device_probed = true; + return 0; +} + +static int driver_remove_hook(struct device *dev) +{ + struct kunit *test = kunit_get_current_test(); + struct driver_test_state *state = (struct driver_test_state *)test->priv; + + state->driver_device_removed = true; + return 0; +} + +static void kunit_device_driver_test(struct kunit *test) +{ + struct device_driver *test_driver; + struct device *test_device; + struct driver_test_state *test_state = kunit_kzalloc(test, sizeof(*test_state), GFP_KERNEL); + + test->priv = test_state; + test_driver = kunit_driver_create(test, "my_driver"); + + // This can fail with an error pointer. + KUNIT_ASSERT_NOT_ERR_OR_NULL(test, test_driver); + + test_driver->probe = driver_probe_hook; + test_driver->remove = driver_remove_hook; + + test_device = kunit_device_register_with_driver(test, "my_device", test_driver); + + // This can fail with an error pointer. + KUNIT_ASSERT_NOT_ERR_OR_NULL(test, test_device); + + // Make sure the probe function was called. + KUNIT_ASSERT_TRUE(test, test_state->driver_device_probed); + + // Add an action to verify cleanup. + devm_add_action(test_device, test_dev_action, &test_state->action_was_run); + + KUNIT_EXPECT_EQ(test, test_state->action_was_run, 0); + + kunit_device_unregister(test, test_device); + test_device = NULL; + + // Make sure the remove hook was called. + KUNIT_ASSERT_TRUE(test, test_state->driver_device_removed); + + // We're going to test this again. + test_state->driver_device_probed = false; + + // 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); + + // This can fail with an error pointer. + KUNIT_ASSERT_NOT_ERR_OR_NULL(test, test_device); + + // Probe was called again. + KUNIT_ASSERT_TRUE(test, test_state->driver_device_probed); + + // Everything is automatically freed here. +} + +static struct kunit_case kunit_device_test_cases[] = { + KUNIT_CASE(kunit_device_test), + KUNIT_CASE(kunit_device_cleanup_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 +826,6 @@ 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..c457593e4913 100644 --- a/lib/kunit/test.c +++ b/lib/kunit/test.c @@ -18,6 +18,7 @@ #include <linux/sched.h>

#include "debugfs.h" +#include "device-impl.h" #include "hooks-impl.h" #include "string-stream.h" #include "try-catch-impl.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

Using struct root_device to create fake devices for tests is something of a hack. The new struct kunit_device is meant for this purpose, so use it instead.

Reviewed-by: Matti Vaittinen mazziesaccount@gmail.com Acked-by: Kees Cook keescook@chromium.org Signed-off-by: David Gow davidgow@google.com --- lib/fortify_kunit.c | 5 +++-- 1 file changed, 3 insertions(+), 2 deletions(-)

diff --git a/lib/fortify_kunit.c b/lib/fortify_kunit.c index c8c33cbaae9e..2e4fedc81621 100644 --- a/lib/fortify_kunit.c +++ b/lib/fortify_kunit.c @@ -15,6 +15,7 @@ */ #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt

+#include <kunit/device.h> #include <kunit/test.h> #include <linux/device.h> #include <linux/slab.h> @@ -269,7 +270,7 @@ DEFINE_ALLOC_SIZE_TEST_PAIR(kvmalloc) size_t len; \ \ /* Create dummy device for devm_kmalloc()-family tests. */ \ - dev = root_device_register(dev_name); \ + dev = kunit_device_register(test, dev_name); \ KUNIT_ASSERT_FALSE_MSG(test, IS_ERR(dev), \ "Cannot register test device\n"); \ \ @@ -303,7 +304,7 @@ DEFINE_ALLOC_SIZE_TEST_PAIR(kvmalloc) checker(len, devm_kmemdup(dev, "Ohai", len, gfp), \ devm_kfree(dev, p)); \ \ - device_unregister(dev); \ + kunit_device_unregister(test, dev); \ } while (0) DEFINE_ALLOC_SIZE_TEST_PAIR(devm_kmalloc)

Using struct root_device to create fake devices for tests is something of a hack. The new struct kunit_device is meant for this purpose, so use it instead.

Acked-by: Mark Brown broonie@kernel.org Signed-off-by: David Gow davidgow@google.com --- sound/soc/soc-topology-test.c | 10 ++-------- 1 file changed, 2 insertions(+), 8 deletions(-)

diff --git a/sound/soc/soc-topology-test.c b/sound/soc/soc-topology-test.c index 2cd3540cec04..70cbccc42a42 100644 --- a/sound/soc/soc-topology-test.c +++ b/sound/soc/soc-topology-test.c @@ -9,6 +9,7 @@ #include <sound/core.h> #include <sound/soc.h> #include <sound/soc-topology.h> +#include <kunit/device.h> #include <kunit/test.h>

/* ===== HELPER FUNCTIONS =================================================== */ @@ -21,26 +22,19 @@ */ static struct device *test_dev;

-static struct device_driver test_drv = { - .name = "sound-soc-topology-test-driver", -}; - static int snd_soc_tplg_test_init(struct kunit *test) { - test_dev = root_device_register("sound-soc-topology-test"); + test_dev = kunit_device_register(test, "sound-soc-topology-test"); test_dev = get_device(test_dev); if (!test_dev) return -ENODEV;

- test_dev->driver = &test_drv; - return 0; }

static void snd_soc_tplg_test_exit(struct kunit *test) { put_device(test_dev); - root_device_unregister(test_dev); }

/*