linux-next: build failure after merge of the driver-core tree

[Jeffrey Hugo]

On 4/11/2023 9:01 AM, Daniel Vetter wrote:
> On Tue, Apr 11, 2023 at 12:40:28PM +0200, Greg KH wrote:
>> On Tue, Apr 11, 2023 at 11:55:20AM +0200, Daniel Vetter wrote:
>>> On Tue, Apr 11, 2023 at 02:38:12PM +1000, Stephen Rothwell wrote:
>>>> Hi all,
>>>>
>>>> After merging the driver-core tree, today's linux-next build (x86_64
>>>> allmodconfig) failed like this:
>>>>
>>>> In file included from include/linux/linkage.h:7,
>>>>                   from include/linux/kernel.h:17,
>>>>                   from drivers/accel/qaic/mhi_qaic_ctrl.c:4:
>>>> drivers/accel/qaic/mhi_qaic_ctrl.c: In function 'mhi_qaic_ctrl_init':
>>>> include/linux/export.h:27:22: error: passing argument 1 of 'class_create' from incompatible pointer type [-Werror=incompatible-pointer-types]
>>>>     27 | #define THIS_MODULE (&__this_module)
>>>>        |                     ~^~~~~~~~~~~~~~~
>>>>        |                      |
>>>>        |                      struct module *
>>>> drivers/accel/qaic/mhi_qaic_ctrl.c:544:38: note: in expansion of macro 'THIS_MODULE'
>>>>    544 |         mqc_dev_class = class_create(THIS_MODULE, MHI_QAIC_CTRL_DRIVER_NAME);
>>>>        |                                      ^~~~~~~~~~~
>>>> In file included from include/linux/device.h:31,
>>>>                   from include/linux/mhi.h:9,
>>>>                   from drivers/accel/qaic/mhi_qaic_ctrl.c:5:
>>>> include/linux/device/class.h:229:54: note: expected 'const char *' but argument is of type 'struct module *'
>>>>    229 | struct class * __must_check class_create(const char *name);
>>>>        |                                          ~~~~~~~~~~~~^~~~
>>>> drivers/accel/qaic/mhi_qaic_ctrl.c:544:25: error: too many arguments to function 'class_create'
>>>>    544 |         mqc_dev_class = class_create(THIS_MODULE, MHI_QAIC_CTRL_DRIVER_NAME);
>>>>        |                         ^~~~~~~~~~~~
>>>> include/linux/device/class.h:229:29: note: declared here
>>>>    229 | struct class * __must_check class_create(const char *name);
>>>>        |                             ^~~~~~~~~~~~
>>>>
>>>> Caused by commit
>>>>
>>>>    1aaba11da9aa ("driver core: class: remove module * from class_create()")
>>>>
>>>> interacting with commit
>>>>
>>>>    566fc96198b4 ("accel/qaic: Add mhi_qaic_cntl")
>>>>
>>>> from the drm tree.
>>>>
>>>> I have applied the following merge fix patch for today.
>>>>
>>>> From: Stephen Rothwell <sfr at canb.auug.org.au>
>>>> Date: Tue, 11 Apr 2023 14:16:57 +1000
>>>> Subject: [PATCH] fixup for "driver core: class: remove module * from class_create()"
>>>>
>>>> interacting with "accel/qaic: Add mhi_qaic_cntl"
>>>>
>>>> Signed-off-by: Stephen Rothwell <sfr at canb.auug.org.au>
>>>
>>> Thanks for the fixup. Since Dave is out I've made a note about this in my
>>> handover mail so it won't get lost in the drm-next merge window pull. I
>>> don't think we need any other coordination than mention it in each pull to
>>> Linus, topic tree seems overkill for this. Plus there's no way I can
>>> untangle the drm tree anyway :-).
>>
>> Want me to submit a patch for the drm tree that moves this to use
>> class_register() instead, which will make the merge/build issue go away
>> for you?  That's my long-term goal here anyway, so converting this new
>> code to this api today would be something I have to do eventually :)
> 
> We kinda closed drm-next for feature work mostly already (just pulling
> stuff in from subtrees), so won't really help for this merge window.
> 
> For everything else I think this is up to Oded, I had no idea qaic needed
> it's entire own dev class and I don't want to dig into this for the risk I
> might freak out :-)
> 
> Adding Oded.
> 
> Cheers, Daniel

Sorry for the mess.

I made a note to update to class_register() once my drm-misc access is 
sorted out.  Looks like we'll address the conflict in the merge window, 
and catch the update to the new API in the following release.

-Jeff