On 12/5/23 09:31, davidgow@xxxxxxxxxx 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()
Thanks a lot David! I have been missing these!
I love the explanation you added under Documentation. Very helpful I'd
say. I only have very minor comments which you can ignore if they don't
make sense to you or the kunit-subsystem.
With or without the suggested changes:
Reviewed-by: Matti Vaittinen <mazziesaccount@xxxxxxxxx>
--- /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@xxxxxxxxxx>
+ */
+
+#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);
I wish the return values for error case(s) were also mentioned. But
please, see my next comment as well.
+
+#endif
+
+#endif
...
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@xxxxxxxxxx>
+ */
+
...
+
+static void kunit_device_release(struct device *d)
+{
+ kfree(to_kunit_device(d));
+}
I see you added the function documentation to the header. I assume this
is the kunit style(?) I may be heretical, but I'd love to see at least a
very short documentation for (all) exported functions here. I think the
arguments are mostly self-explatonary, but at least for me the return
values aren't that obvious. Whether they are kerneldoc or not is not
that important to me.
I think you did a great job adding docs under Documentation/ (and the
header) - but at least I tend to just jump to function implementation
when I need to figure out how it behaves. Having doc (or pointer to doc)
also here helps. I don't think it's that widely spread practice to add
docs to the headers(?)
+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)
Very much nitpicking only - but do you think either the "__"-prefix or
the "_internal"-suffix would be enough and not both? (Just to make
function a tad shorter, not that it matters much though).
+{
+ 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;
+}
...
--
Matti Vaittinen
Linux kernel developer at ROHM Semiconductors
Oulu Finland
~~ When things go utterly wrong vim users can always type :help! ~~
