Messages in this thread | | | Date | Thu, 23 Mar 2023 13:00:27 +0200 | From | Matti Vaittinen <> | Subject | Re: [PATCH v5 1/8] drivers: kunit: Generic helpers for test device creation |
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On 3/23/23 12:27, Greg Kroah-Hartman wrote: > On Thu, Mar 23, 2023 at 12:01:15PM +0200, Matti Vaittinen wrote: >> On 3/23/23 10:58, Greg Kroah-Hartman wrote: >>> On Thu, Mar 23, 2023 at 07:17:40AM +0000, Vaittinen, Matti wrote: >>>> On 3/22/23 20:57, Greg Kroah-Hartman wrote: >>>>> On Wed, Mar 22, 2023 at 03:48:00PM +0200, Matti Vaittinen wrote: >>>>>> Hi Greg, >>>>>> >>>>>> Thanks for looking at this. >>>>>> >>>>>> On 3/22/23 14:07, Greg Kroah-Hartman wrote: >>>>>>> On Wed, Mar 22, 2023 at 11:05:55AM +0200, Matti Vaittinen wrote: >> >>>>>> The biggest thing for me is that I don't like the idea of creating own 'test >>>>>> device' in <add subsystem here> while we already have some in DRM (or >>>>>> others). Thus, I do see value in adding generic helpers for supporting >>>>>> running KUnit tests on devm_* APIs. Hence it'd be good to have _some_ >>>>>> support for it. >>>>> >>>>> I agree, let's use a virtual device and a virtual bus (you can use the >>>>> auxbus code for this as that's all there for this type of thing) >>>> >>>> Hm. The auxiliary_devices require parent. What would be the best way to >>>> deal with that in KUnit tests? >>> >>> If you use NULL as the parent, it goes into the root. >> >> As far as I read this is not the case with auxiliary devices. Judging the >> docs they were intended to be representing some part of a (parent) device. I >> see the auxiliary_device_init() has explicit check for parent being >> populated: >> >> int auxiliary_device_init(struct auxiliary_device *auxdev) >> { >> struct device *dev = &auxdev->dev; >> >> if (!dev->parent) { >> pr_err("auxiliary_device has a NULL dev->parent\n"); >> return -EINVAL; >> } > > Yes as it wants to "split" a device up into smaller devices. So make a > real device that it can hang off of.
Yep. This is what led me to the root_device_register()... :rolleyes: And seein the root-device alone could do what I need - adding auxiliary device on top of it just for the sake of adding one seems a bit of an over-engineering to me :)
>> As I wrote in another mail, I thought of using a root_device for this IIO >> test as was suggested by David. To tell the truth, implementing a kunit bus >> device is starting to feel a bit overwhelming... I started just adding a >> driver for a light sensor, ended up adding a helper for IIO gain-time-scale >> conversions and I am slightly reluctant to going the extra-extra mile of >> adding some UT infrastructure in the context of this driver work... > > I think it is worth it as the driver core has no tests. So it obviously > must be correct, right? :)
Doh. Greg, I hate you :) How could one argue with something like this? I think I will submit the v6 with the root_device_register() due to the aux-device requiring it in any case. I know that will end up to your table still as IIO is going through your hands anyways.
I will however take a look at what Maxime said about devm unwinding not being done w/o a bus because I think I saw the unwinding done in these IIO tests even when using the root_device_register() root_device_unregister(). If the unwinding really is not done, then I will come back to this auxiliary device rehearsal
-- Matti Vaittinen Linux kernel developer at ROHM Semiconductors Oulu Finland
~~ When things go utterly wrong vim users can always type :help! ~~
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