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

[Jeff Layton <jlayton@kernel.org>]

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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@kernel.org/

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@kernel.org>

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From: kernel test robot <lkp@intel.com>
To: Jeff Layton <jlayton@kernel.org>
Cc: oe-kbuild-all@lists.linux.dev
Subject: [jlayton:mgtime 5/13] inode.c:undefined reference to `__invalid_cmpxchg_size'
Date: Tue, 9 Jul 2024 19:40:55 +0800
Message-ID: <202407091931.mztaeJHw-lkp@intel.com>

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@intel.com/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@intel.com/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@intel.com>
| Closes: https://lore.kernel.org/oe-kbuild-all/202407091931.mztaeJHw-lkp@intel.com/

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