[linux-next:master 6848/6860] mm/util.c:1105:6: warning: no previous prototype for function 'flush_dcache_folio'

tree:   https://git.kernel.org/pub/scm/linux/kernel/git/next/linux-next.git master
head:   8ca403f3e7a23c4513046ad8d107adfbe4703362
commit: 284e3a59cc20335f65f2fb5215230d63b32f25d4 [6848/6860] Merge remote-tracking branch 'folio/for-next'
config: mips-buildonly-randconfig-r005-20210810 (attached as .config)
compiler: clang version 14.0.0 (https://github.com/llvm/llvm-project 767496d19cb9a1fbba57ff08095faa161998ee36)
reproduce (this is a W=1 build):
        wget https://raw.githubusercontent.com/intel/lkp-tests/master/sbin/make.cross -O ~/bin/make.cross
        chmod +x ~/bin/make.cross
        # https://git.kernel.org/pub/scm/linux/kernel/git/next/linux-next.git/commit/?id=284e3a59cc20335f65f2fb5215230d63b32f25d4
        git remote add linux-next https://git.kernel.org/pub/scm/linux/kernel/git/next/linux-next.git
        git fetch --no-tags linux-next master
        git checkout 284e3a59cc20335f65f2fb5215230d63b32f25d4
        # save the attached .config to linux build tree
        COMPILER_INSTALL_PATH=$HOME/0day COMPILER=clang make.cross ARCH=mips 

If you fix the issue, kindly add following tag as appropriate
Reported-by: kernel test robot <redacted>

All warnings (new ones prefixed by >>):

quoted

mm/util.c:1105:6: warning: no previous prototype for function 'flush_dcache_folio' [-Wmissing-prototypes]

   void flush_dcache_folio(struct folio *folio)
        ^
   mm/util.c:1105:1: note: declare 'static' if the function is not intended to be used outside of this translation unit
   void flush_dcache_folio(struct folio *folio)
   ^
   static 
   1 warning generated.


vim +/flush_dcache_folio +1105 mm/util.c

d1089c128effba Matthew Wilcox (Oracle  2020-12-16  1103) 
d1089c128effba Matthew Wilcox (Oracle  2020-12-16  1104) #ifndef ARCH_IMPLEMENTS_FLUSH_DCACHE_FOLIO
d1089c128effba Matthew Wilcox (Oracle  2020-12-16 @1105) void flush_dcache_folio(struct folio *folio)

:::::: The code at line 1105 was first introduced by commit
:::::: d1089c128effba5c3f298e277b0422193ae1a943 mm: Add flush_dcache_folio()

:::::: TO: Matthew Wilcox (Oracle) [off-list ref]
:::::: CC: Matthew Wilcox (Oracle) [off-list ref]

---
0-DAY CI Kernel Test Service, Intel Corporation
https://lists.01.org/hyperkitty/list/kbuild-all@lists.01.org