Fwd: [jlayton:mgtime 5/13] inode.c:undefined reference to `__invalid_cmpxchg_size'

[Jeff Layton]

I've been getting some of these warning emails from the KTR. I think
this is in reference to this patch, which adds a 64-bit try_cmpxchg in
the timestamp handling code:

    https://lore.kernel.org/linux-fsdevel/20240708-mgtime-v4-0-a0f3c6fb57f3@xxxxxxxxxx/

On m68k, there is a prototype for __invalid_cmpxchg_size, but no actual
function, AFAICT. Should that be defined somewhere, or is this a
deliberate way to force a build break in this case?

More to the point though: do I need to do anything special for m86k
here (or for other arches that can't do a native 64-bit cmpxchg)?

Thanks,
-- 
Jeff Layton <jlayton@xxxxxxxxxx>
> --- Begin Message ---
> tree:   https://git.kernel.org/pub/scm/linux/kernel/git/jlayton/linux.git mgtime
> head:   81b2439edd7c9f966afcb091f414b7f219cda8f6
> commit: 2265b64634f4af479ffb0c478409cfd56ec6dc4d [5/13] fs: add infrastructure for multigrain timestamps
> config: m68k-allyesconfig (https://download.01.org/0day-ci/archive/20240709/202407091931.mztaeJHw-lkp@xxxxxxxxx/config)
> compiler: m68k-linux-gcc (GCC) 13.2.0
> reproduce (this is a W=1 build): (https://download.01.org/0day-ci/archive/20240709/202407091931.mztaeJHw-lkp@xxxxxxxxx/reproduce)
>
> If you fix the issue in a separate patch/commit (i.e. not just a new version of
> the same patch/commit), kindly add following tags
> | Reported-by: kernel test robot <lkp@xxxxxxxxx>
> | Closes: https://lore.kernel.org/oe-kbuild-all/202407091931.mztaeJHw-lkp@xxxxxxxxx/
>
> All errors (new ones prefixed by >>):
>
>    m68k-linux-ld: fs/inode.o: in function `inode_set_ctime_current':
> >> inode.c:(.text+0x167a): undefined reference to `__invalid_cmpxchg_size'
>
> -- 
> 0-DAY CI Kernel Test Service
> https://github.com/intel/lkp-tests/wiki
>
> --- End Message ---