On Mon, Mar 27, 2023 at 03:20:06PM +0300, Matti Vaittinen wrote: > On 3/27/23 15:01, Greg Kroah-Hartman wrote: > > On Mon, Mar 27, 2023 at 02:34:02PM +0300, Matti Vaittinen wrote: > > > A few tests need to have a valid struct device. One such example is > > > tests which want to be testing devm-managed interfaces. > > > > > > Add kunit wrapper for root_device_[un]register(), which create a root > > > device and also add a kunit managed clean-up routine for the device > > > destruction upon test exit. > > > > I really do not like this as a "root device" is a horrible hack and > > should only be used if you have to hang other devices off of it and you > > don't have a real device to tie those devices to. > > > > Here you are abusing it and attempting to treat it as a real device, > > which it is not at all, because: > > > > > Special note: In some cases the device reference-count does not reach > > > zero and devm-unwinding is not done if device is not sitting on a bus. > > > The root_device_[un]register() are dealing with such devices and thus > > > this interface may not be usable by all in its current form. More > > > information can be found from: > > > https://lore.kernel.org/dri-devel/20221117165311.vovrc7usy4efiytl@houat/ > > > > See, not a real device, doesn't follow normal "struct device" rules and > > lifetimes, don't try to use it for a test as it will only cause problems > > and you will be forced to work around that in a test. > > Ok. I understood using the root-device has been a work-around in some other > tests. Thus continuing use it for tests where we don't need the bus until we > have a proper alternative was suggested by David. > > > Do the right thing here, create a fake bus and add devices to it. > > > > Heck, I'll even write that code if you want it, what's the requirement, > > something like: > > struct device *kunit_device_create(struct kunit *test, const char *name); > > void kunit_device_destroy(struct device *dev); > > Thanks for the offer Greg. This, however, is being already worked on by > David. I don't want to step on his toes by writing the same thing, nor do I > think I should be pushing him to rush on his work. Ok, David, my offer stands, if you want me to write this I will be glad to do so. thanks, greg k-h
