Hi Chih-En,

Thank you for the patch! Yet something to improve:

[auto build test ERROR on v6.1-rc7]
[also build test ERROR on next-20221220]
[cannot apply to akpm-mm/mm-everything tip/perf/core acme/perf/core linus/master v6.1 v6.1-rc8]
[If your patch is applied to the wrong git tree, kindly drop us a note.
And when submitting patch, we suggest to use '--base' as documented in
https://git-scm.com/docs/git-format-patch#_base_tree_information]

url:    https://github.com/intel-lab-lkp/linux/commits/Chih-En-Lin/Introduce-Copy-On-Write-to-Page-Table/20221220-153207
patch link:    https://lore.kernel.org/r/20221220072743.3039060-3-shiyn.lin%40gmail.com
patch subject: [PATCH v3 02/14] mm: Add Copy-On-Write PTE to fork()
config: s390-allmodconfig
compiler: s390-linux-gcc (GCC) 12.1.0
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://github.com/intel-lab-lkp/linux/commit/7ddfab485179ecb834e4fcdf1fe401837d9d33a5
        git remote add linux-review https://github.com/intel-lab-lkp/linux
        git fetch --no-tags linux-review Chih-En-Lin/Introduce-Copy-On-Write-to-Page-Table/20221220-153207
        git checkout 7ddfab485179ecb834e4fcdf1fe401837d9d33a5
        # save the config file
        mkdir build_dir && cp config build_dir/.config
        COMPILER_INSTALL_PATH=$HOME/0day COMPILER=gcc-12.1.0 make.cross W=1 O=build_dir ARCH=s390 olddefconfig
        COMPILER_INSTALL_PATH=$HOME/0day COMPILER=gcc-12.1.0 make.cross W=1 O=build_dir ARCH=s390 SHELL=/bin/bash

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

All errors (new ones prefixed by >>):

   In file included from arch/s390/include/asm/page.h:208,
                    from arch/s390/include/asm/thread_info.h:26,
                    from include/linux/thread_info.h:60,
                    from arch/s390/include/asm/preempt.h:6,
                    from include/linux/preempt.h:78,
                    from include/linux/smp.h:110,
                    from include/linux/kernel_stat.h:5,
                    from mm/memory.c:42:
   mm/memory.c: In function 'copy_cow_pte_range':
>> include/asm-generic/memory_model.h:25:33: error: initialization of 'pgtable_t' {aka 'pte_t *'} from incompatible pointer type 'struct page *' [-Werror=incompatible-pointer-types]
      25 | #define __pfn_to_page(pfn)      (vmemmap + (pfn))
         |                                 ^
   include/asm-generic/memory_model.h:53:21: note: in expansion of macro '__pfn_to_page'
      53 | #define pfn_to_page __pfn_to_page
         |                     ^~~~~~~~~~~~~
   arch/s390/include/asm/pgtable.h:1411:23: note: in expansion of macro 'pfn_to_page'
    1411 | #define pmd_page(pmd) pfn_to_page(pmd_pfn(pmd))
         |                       ^~~~~~~~~~~
   mm/memory.c:1188:31: note: in expansion of macro 'pmd_page'
    1188 |         pgtable_t pte_table = pmd_page(*src_pmd);
         |                               ^~~~~~~~
   cc1: some warnings being treated as errors


vim +25 include/asm-generic/memory_model.h

8f6aac419bd590 Christoph Lameter  2007-10-16  23  
af901ca181d92a André Goddard Rosa 2009-11-14  24  /* memmap is virtually contiguous.  */
8f6aac419bd590 Christoph Lameter  2007-10-16 @25  #define __pfn_to_page(pfn)	(vmemmap + (pfn))
32272a26974d20 Martin Schwidefsky 2008-12-25  26  #define __page_to_pfn(page)	(unsigned long)((page) - vmemmap)
8f6aac419bd590 Christoph Lameter  2007-10-16  27  

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