Hi "Thomas,

I love your patch! Yet something to improve:

[auto build test ERROR on mmotm/master]

url:    https://github.com/0day-ci/linux/commits/Thomas-Hellstr-m-VMware/mm-Fix-a-huge-pud-insertion-race-during-faulting/20191024-175905
base:   git://git.cmpxchg.org/linux-mmotm.git master
config: i386-tinyconfig (attached as .config)
compiler: gcc-7 (Debian 7.4.0-14) 7.4.0
reproduce:
        # save the attached .config to linux build tree
        make ARCH=i386 

If you fix the issue, kindly add following tag
Reported-by: kbuild test robot <lkp@intel.com>

All errors (new ones prefixed by >>):

   In file included from arch/x86/include/asm/pgtable.h:1466:0,
                    from include/linux/mm.h:99,
                    from include/linux/memcontrol.h:20,
                    from include/linux/swap.h:9,
                    from include/linux/suspend.h:5,
                    from arch/x86/kernel/asm-offsets.c:13:
   include/asm-generic/pgtable.h: In function 'pud_none_or_trans_huge_or_dev_or_clear_bad':
>> include/asm-generic/pgtable.h:920:52: error: implicit declaration of function 'pud_devmap'; did you mean 'pud_mkdevmap'? [-Werror=implicit-function-declaration]
     if (pud_none(pudval) || pud_trans_huge(pudval) || pud_devmap(pudval))
                                                       ^~~~~~~~~~
                                                       pud_mkdevmap
   In file included from include/linux/memcontrol.h:20:0,
                    from include/linux/swap.h:9,
                    from include/linux/suspend.h:5,
                    from arch/x86/kernel/asm-offsets.c:13:
   include/linux/mm.h: At top level:
>> include/linux/mm.h:572:19: error: static declaration of 'pud_devmap' follows non-static declaration
    static inline int pud_devmap(pud_t pud)
                      ^~~~~~~~~~
   In file included from arch/x86/include/asm/pgtable.h:1466:0,
                    from include/linux/mm.h:99,
                    from include/linux/memcontrol.h:20,
                    from include/linux/swap.h:9,
                    from include/linux/suspend.h:5,
                    from arch/x86/kernel/asm-offsets.c:13:
   include/asm-generic/pgtable.h:920:52: note: previous implicit declaration of 'pud_devmap' was here
     if (pud_none(pudval) || pud_trans_huge(pudval) || pud_devmap(pudval))
                                                       ^~~~~~~~~~
   cc1: some warnings being treated as errors
   make[2]: *** [arch/x86/kernel/asm-offsets.s] Error 1
   make[2]: Target '__build' not remade because of errors.
   make[1]: *** [prepare0] Error 2
   make[1]: Target 'prepare' not remade because of errors.
   make: *** [sub-make] Error 2
   13 real  5 user  3 sys  72.35% cpu 	make prepare

vim +920 include/asm-generic/pgtable.h

   914	
   915	/* See pmd_none_or_trans_huge_or_clear_bad for discussion. */
   916	static inline int pud_none_or_trans_huge_or_dev_or_clear_bad(pud_t *pud)
   917	{
   918		pud_t pudval = READ_ONCE(*pud);
   919	
 > 920		if (pud_none(pudval) || pud_trans_huge(pudval) || pud_devmap(pudval))
   921			return 1;
   922		if (unlikely(pud_bad(pudval))) {
   923			pud_clear_bad(pud);
   924			return 1;
   925		}
   926		return 0;
   927	}
   928	

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