Hi Zi,

[auto build test WARNING on mmotm/master]
[also build test WARNING on v4.12-rc2 next-20170525]
[if your patch is applied to the wrong git tree, please drop us a note to help improve the system]

url:    https://github.com/0day-ci/linux/commits/Zi-Yan/mm-page-migration-enhancement-for-thp/20170526-003749
base:   git://git.cmpxchg.org/linux-mmotm.git master
config: i386-randconfig-x017-201721 (attached as .config)
compiler: gcc-6 (Debian 6.2.0-3) 6.2.0 20160901
reproduce:
        # save the attached .config to linux build tree
        make ARCH=i386 

All warnings (new ones prefixed by >>):

   In file included from arch/x86/mm/gup.c:12:0:
   include/linux/swapops.h: In function 'swp_entry_to_pmd':
>> include/linux/swapops.h:222:2: warning: braces around scalar initializer
     return (pmd_t){{ 0 }};
     ^~~~~~
   include/linux/swapops.h:222:2: note: (near initialization for '(anonymous).pmd')

vim +222 include/linux/swapops.h

2182e56bf Zi Yan 2017-05-25  206  		struct page *new)
2182e56bf Zi Yan 2017-05-25  207  {
2182e56bf Zi Yan 2017-05-25  208  	BUILD_BUG();
2182e56bf Zi Yan 2017-05-25  209  }
2182e56bf Zi Yan 2017-05-25  210  
2182e56bf Zi Yan 2017-05-25  211  static inline void pmd_migration_entry_wait(struct mm_struct *m, pmd_t *p) { }
2182e56bf Zi Yan 2017-05-25  212  
2182e56bf Zi Yan 2017-05-25  213  static inline swp_entry_t pmd_to_swp_entry(pmd_t pmd)
2182e56bf Zi Yan 2017-05-25  214  {
2182e56bf Zi Yan 2017-05-25  215  	BUILD_BUG();
2182e56bf Zi Yan 2017-05-25  216  	return swp_entry(0, 0);
2182e56bf Zi Yan 2017-05-25  217  }
2182e56bf Zi Yan 2017-05-25  218  
2182e56bf Zi Yan 2017-05-25  219  static inline pmd_t swp_entry_to_pmd(swp_entry_t entry)
2182e56bf Zi Yan 2017-05-25  220  {
2182e56bf Zi Yan 2017-05-25  221  	BUILD_BUG();
2182e56bf Zi Yan 2017-05-25 @222  	return (pmd_t){{ 0 }};
2182e56bf Zi Yan 2017-05-25  223  }
2182e56bf Zi Yan 2017-05-25  224  
2182e56bf Zi Yan 2017-05-25  225  static inline int is_pmd_migration_entry(pmd_t pmd)
2182e56bf Zi Yan 2017-05-25  226  {
2182e56bf Zi Yan 2017-05-25  227  	return 0;
2182e56bf Zi Yan 2017-05-25  228  }
2182e56bf Zi Yan 2017-05-25  229  #endif
2182e56bf Zi Yan 2017-05-25  230  

:::::: The code at line 222 was first introduced by commit
:::::: 2182e56bfe80b55d1a9a8e8de04e6a5578b1dce0 mm: thp: enable thp migration in generic path

:::::: TO: Zi Yan <zi.yan@cs.rutgers.edu>
:::::: CC: 0day robot <fengguang.wu@intel.com>

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