Re: [PATCH v2 02/33] drm/tests: Add Kunit Helpers

[Noralf Trønnes]

Den 26.09.2022 11.36, skrev Maxime Ripard:
> Hi Noralf,
> 
> On Sat, Sep 24, 2022 at 08:06:17PM +0200, Noralf Trønnes wrote:
>> Den 24.09.2022 19.56, skrev Noralf Trønnes:
>>>
>>>
>>> Den 22.09.2022 16.25, skrev Maxime Ripard:
>>>> As the number of kunit tests in KMS grows further, we start to have
>>>> multiple test suites that, for example, need to register a mock DRM
>>>> driver to interact with the KMS function they are supposed to test.
>>>>
>>>> Let's add a file meant to provide those kind of helpers to avoid
>>>> duplication.
>>>>
>>>> Signed-off-by: Maxime Ripard <maxime@xxxxxxxxxx>
>>>>
>>>> diff --git a/drivers/gpu/drm/tests/Makefile b/drivers/gpu/drm/tests/Makefile
>>>> index 2d9f49b62ecb..b29ef1085cad 100644
>>>> --- a/drivers/gpu/drm/tests/Makefile
>>>> +++ b/drivers/gpu/drm/tests/Makefile
>>>> @@ -8,6 +8,7 @@ obj-$(CONFIG_DRM_KUNIT_TEST) += \
>>>>  	drm_format_helper_test.o \
>>>>  	drm_format_test.o \
>>>>  	drm_framebuffer_test.o \
>>>> +	drm_kunit_helpers.o \
>>>>  	drm_mm_test.o \
>>>>  	drm_plane_helper_test.o \
>>>>  	drm_rect_test.o
>>>> diff --git a/drivers/gpu/drm/tests/drm_kunit_helpers.c b/drivers/gpu/drm/tests/drm_kunit_helpers.c
>>>> new file mode 100644
>>>> index 000000000000..7ebd620481c1
>>>> --- /dev/null
>>>> +++ b/drivers/gpu/drm/tests/drm_kunit_helpers.c
>>>> @@ -0,0 +1,54 @@
>>>> +#include <drm/drm_drv.h>
>>>> +#include <drm/drm_managed.h>
>>>> +
>>>> +#include <linux/device.h>
>>>> +
>>>> +static const struct drm_mode_config_funcs drm_mode_config_funcs = {
>>>> +};
>>>> +
>>>> +static const struct drm_driver drm_mode_driver = {
>>>> +};
>>>> +
>>>> +static void drm_kunit_free_device(struct drm_device *drm, void *ptr)
>>>> +{
>>>> +	struct device *dev = ptr;
>>>> +
>>>> +	root_device_unregister(dev);
>>>> +}
>>>> +
>>>> +struct drm_device *drm_kunit_device_init(const char *name)
>>>> +{
>>>> +	struct drm_device *drm;
>>>> +	struct device *dev;
>>>> +	int ret;
>>>> +
>>>> +	dev = root_device_register(name);
>>>> +	if (IS_ERR(dev))
>>>> +		return ERR_CAST(dev);
>>>> +
>>>> +	drm = drm_dev_alloc(&drm_mode_driver, dev);
>>>
>>> I can't find drm being freed anywhere?
>>> Maybe you could assign it to drm->managed.final_kfree.
> 
> There's a drm_dev_put in the test_exit hook which should free it.
> 

I see now, there's a drmm_add_final_kfree() in drm_dev_alloc().

Noralf.

>> Perhaps a better solution would be to use devm_drm_dev_alloc() and
>> unregister the root device on exit. That avoids reaching into the drm
>> managed internals and it looks more like a regular driver.
> 
> But yeah, this is a good idea, I'll do it.
> 
> Maxime