[linux-next:master 5068/5074] mm/kasan/common.c:89:14: warning: no previous prototype for function '__kasan_never_merge'

[kernel test robot <lkp@xxxxxxxxx>]

tree:   https://git.kernel.org/pub/scm/linux/kernel/git/next/linux-next.git master
head:   3e14f70c05cda4794901ed8f976de3a88deebcc0
commit: 622c9ff2b804a1de896e757f8fe3a71fcef2941b [5068/5074] kasan, mm: allow cache merging with no metadata
config: x86_64-randconfig-a003-20201111 (attached as .config)
compiler: clang version 12.0.0 (https://github.com/llvm/llvm-project 874b0a0b9db93f5d3350ffe6b5efda2d908415d0)
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
        # install x86_64 cross compiling tool for clang build
        # apt-get install binutils-x86-64-linux-gnu
        # https://git.kernel.org/pub/scm/linux/kernel/git/next/linux-next.git/commit/?id=622c9ff2b804a1de896e757f8fe3a71fcef2941b
        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 622c9ff2b804a1de896e757f8fe3a71fcef2941b
        # save the attached .config to linux build tree
        COMPILER_INSTALL_PATH=$HOME/0day COMPILER=clang make.cross ARCH=x86_64 

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

All warnings (new ones prefixed by >>):

>> mm/kasan/common.c:89:14: warning: no previous prototype for function '__kasan_never_merge' [-Wmissing-prototypes]
   slab_flags_t __kasan_never_merge(slab_flags_t flags)
                ^
   mm/kasan/common.c:89:1: note: declare 'static' if the function is not intended to be used outside of this translation unit
   slab_flags_t __kasan_never_merge(slab_flags_t flags)
   ^
   static 
   1 warning generated.

vim +/__kasan_never_merge +89 mm/kasan/common.c

    84	
    85	/*
    86	 * Only allow cache merging when stack collection is disabled and no metadata
    87	 * is present.
    88	 */
  > 89	slab_flags_t __kasan_never_merge(slab_flags_t flags)
    90	{
    91		if (kasan_stack_collection_enabled())
    92			return flags;
    93		return flags & ~SLAB_KASAN;
    94	}
    95	

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

Attachment: .config.gz
Description: application/gzip