Re: [PATCH 3/4] mm: prevent KSM from completely breaking VMA merging

[kernel test robot <lkp@intel.com>]

Hi Lorenzo,

kernel test robot noticed the following build errors:

[auto build test ERROR on akpm-mm/mm-everything]

url:    https://github.com/intel-lab-lkp/linux/commits/Lorenzo-Stoakes/mm-ksm-have-KSM-VMA-checks-not-require-a-VMA-pointer/20250519-165315
base:   https://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm.git mm-everything
patch link:    https://lore.kernel.org/r/418d3edbec3a718a7023f1beed5478f5952fc3df.1747431920.git.lorenzo.stoakes%40oracle.com
patch subject: [PATCH 3/4] mm: prevent KSM from completely breaking VMA merging
config: x86_64-buildonly-randconfig-001-20250519 (https://download.01.org/0day-ci/archive/20250519/202505192132.NsAm4haK-lkp@intel.com/config)
compiler: clang version 20.1.2 (https://github.com/llvm/llvm-project 58df0ef89dd64126512e4ee27b4ac3fd8ddf6247)
reproduce (this is a W=1 build): (https://download.01.org/0day-ci/archive/20250519/202505192132.NsAm4haK-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/202505192132.NsAm4haK-lkp@intel.com/

All errors (new ones prefixed by >>):

>> mm/vma.c:2589:15: error: call to undeclared function 'ksm_vma_flags'; ISO C99 and later do not support implicit function declarations [-Wimplicit-function-declaration]
    2589 |         map->flags = ksm_vma_flags(map->mm, map->file, map->flags);
         |                      ^
   mm/vma.c:2761:10: error: call to undeclared function 'ksm_vma_flags'; ISO C99 and later do not support implicit function declarations [-Wimplicit-function-declaration]
    2761 |         flags = ksm_vma_flags(mm, NULL, flags);
         |                 ^
   2 errors generated.


vim +/ksm_vma_flags +2589 mm/vma.c

  2586	
  2587	static void update_ksm_flags(struct mmap_state *map)
  2588	{
> 2589		map->flags = ksm_vma_flags(map->mm, map->file, map->flags);
  2590	}
  2591	

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