Re: [PATCH v1 0/3] <linux/mod_devicetable.h> deprecation continues

[Nathan Chancellor <nathan@kernel.org>]

On Mon, Oct 05, 2026 at 05:23:16PM +0200, Nathan Chancellor wrote:
> > this is a next step in the deprecation of <linux/mod_devicetable.h>.
> > scripts/mod/devicetable-offsets.c and scripts/mod/file2alias.c are the
> > only users of that header that use more than a few device-id structs. So
> > their number of lines actually grows when unfolding the needed includes
> > into them. Still it is a reduction in build dependencies.
> > 
> > I suggest to take this via kbuild during the merge window. Would be great to
> > cook in next for a while before.
> > 
> > Best regards
> > Uwe
> > 
> > Uwe Kleine-König (The Capable Hub) (3):
> >   Move struct cpu_feature to <linux/cpufeature.h>
> >   devicetable-offsets: Include the needed device-id headers instead of
> >     the catch-all
> >   file2alias: Include the needed device-id headers instead of the
> >     catch-all
> > 
> >  arch/loongarch/kvm/main.c         |  2 +-
> >  include/linux/cpufeature.h        | 12 ++++++-
> >  include/linux/mod_devicetable.h   | 13 -------
> >  scripts/mod/devicetable-offsets.c | 57 ++++++++++++++++++++++++++++++-
> >  scripts/mod/file2alias.c          | 56 +++++++++++++++++++++++++++++-
> >  5 files changed, 123 insertions(+), 17 deletions(-)
> 
> My apologies for taking some time to get to this. I was planning on
> building it using my personal test matrix on a local machine at home
> while travelling for Plumbers to avoid tying up my main workstation but
> my home's internet connection has been down for two weeks with very
> little hope of getting it online before I am back...
> 
> Sashiko has a few comments that seem relevant (most of them are the same
> issue):
> 
>   https://sashiko.dev/#/patchset/cover.1789988540.git.u.kleine-koenig@baylibre.com
> 
> I have applied it on top of next-20261005 to see what conflicts are
> looking like. I see a merge conflict with this series from
> 
>   d59717cfbe1e ("firmware: arm_scmi: Add SCMI device table alias support")
> 
> in the soc tree, which is fairly trivial. There is a semantic conflict
> that results in a build error from
> 
>   fe7f2a805443 ("firmware: smccc: Add an Arm SMCCC bus")
> 
> in the arm64 tree, which is also trivial but subtle.
> 
>   scripts/mod/devicetable-offsets.c:317:2: error: invalid application of 'sizeof' to an incomplete type 'struct arm_smccc_device_id'
>     317 |         DEVID(arm_smccc_device_id);
>         |         ^~~~~~~~~~~~~~~~~~~~~~~~~~
>   scripts/mod/devicetable-offsets.c:62:43: note: expanded from macro 'DEVID'
>      62 | #define DEVID(devid) DEFINE(SIZE_##devid, sizeof(struct devid))
>         |                      ~~~~~~~~~~~~~~~~~~~~~^~~~~~~~~~~~~~~~~~~~~
>   include/linux/kbuild.h:6:62: note: expanded from macro 'DEFINE'
>       6 |         asm volatile("\n.ascii \"->" #sym " %0 " #val "\"" : : "i" (val))
>         |                                                                     ^~~
>   scripts/mod/devicetable-offsets.c:317:8: note: forward declaration of 'struct arm_smccc_device_id'
>     317 |         DEVID(arm_smccc_device_id);
>         |               ^
>   scripts/mod/devicetable-offsets.c:318:2: error: offsetof of incomplete type 'struct arm_smccc_device_id'
>     318 |         DEVID_FIELD(arm_smccc_device_id, func_id);
>         |         ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
>   scripts/mod/devicetable-offsets.c:64:32: note: expanded from macro 'DEVID_FIELD'
>      64 |         DEFINE(OFF_##devid##_##field, offsetof(struct devid, field))
>         |         ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
>   include/linux/stddef.h:16:32: note: expanded from macro 'offsetof'
>      16 | #define offsetof(TYPE, MEMBER)  __builtin_offsetof(TYPE, MEMBER)
>         |                                 ^
>   include/linux/kbuild.h:6:62: note: expanded from macro 'DEFINE'
>       6 |         asm volatile("\n.ascii \"->" #sym " %0 " #val "\"" : : "i" (val))
>         |                                                                     ^~~
>   scripts/mod/devicetable-offsets.c:317:8: note: forward declaration of 'struct arm_smccc_device_id'
>     317 |         DEVID(arm_smccc_device_id);
>         |               ^
>   2 errors generated.
> 
> If you would like this in 7.4-rc1, I am not opposed to sticking your v2
> into -next now but I plan to finalize the Kbuild tree for 7.4 around
> October 15, so we'd only get a week or so of build coverage. If that
> feels like too little, we should defer this until after 7.4-rc1 is out.

Two more issues came up in my testing.

ARCH=loongarch defconfig:

  In file included from include/linux/mmzone.h:20,
                   from include/linux/gfp.h:7,
                   from include/linux/xarray.h:16,
                   from include/linux/list_lru.h:14,
                   from include/linux/fs/super_types.h:7,
                   from include/linux/fs/super.h:5,
                   from include/linux/fs.h:5,
                   from arch/loongarch/include/asm/elf.h:9,
                   from arch/loongarch/include/asm/cpufeature.h:13,
                   from include/linux/cpufeature.h:23,
                   from scripts/mod/devicetable-offsets.c:3:
  include/linux/page-flags-layout.h:6:10: fatal error: generated/bounds.h: No such file or directory
      6 | #include <generated/bounds.h>
        |          ^~~~~~~~~~~~~~~~~~~~
  compilation terminated.
  make[4]: *** [scripts/Makefile.build:185: scripts/mod/devicetable-offsets.s] Error 1

ARCH=s390 defconfig:

  drivers/s390/crypto/pkey_ep11.c:23:28: error: array type has incomplete element type 'struct ap_device_id'
     23 | static struct ap_device_id pkey_ep11_card_ids[] = {
        |                            ^~~~~~~~~~~~~~~~~~
  make[7]: *** [scripts/Makefile.build:290: drivers/s390/crypto/pkey_ep11.o] Error 1
  drivers/s390/crypto/pkey_cca.c:22:28: error: array type has incomplete element type 'struct ap_device_id'
     22 | static struct ap_device_id pkey_cca_card_ids[] = {
        |                            ^~~~~~~~~~~~~~~~~
  make[7]: *** [scripts/Makefile.build:290: drivers/s390/crypto/pkey_cca.o] Error 1

-- 
Cheers,
Nathan