Hi David, Thanks a lot for working on this.
On Tue, Dec 05, 2023 at 03:31:33PM +0800, [email protected] wrote: > 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 <[email protected]> > --- > 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 ^ Devices > +---------------------------------- > + > +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()``. I think we should add a test for that, just like we did for root and platform devices. We've been bitten by that before :) > +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 <[email protected]> > + */ > + > +#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 <[email protected]> > + */ > + > +#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); The preferred syntax is sizeof(*kunit_dev) here > + 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); > +} Oh, it looks like you do check there, sorry. I guess I would have expected an explicit test for that, but that works :) > + > +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); Should we test that the probe (and remove) hooks has been called too? Maxime
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