Hi Wei,

Thank you for the patch! Yet something to improve:

[auto build test ERROR on tip/x86/mm]
[also build test ERROR on tip/auto-latest linus/master v5.4 next-20191206]
[if your patch is applied to the wrong git tree, please drop us a note to help
improve the system. BTW, we also suggest to use '--base' option to specify the
base tree in git format-patch, please see https://stackoverflow.com/a/37406982]

url:    https://github.com/0day-ci/linux/commits/Wei-Yang/x86-mm-Remove-second-argument-of-split_mem_range/20191207-061345
base:   https://git.kernel.org/pub/scm/linux/kernel/git/tip/tip.git 7f264dab5b60343358e788d4c939c166c22ea4a2
config: i386-tinyconfig (attached as .config)
compiler: gcc-7 (Debian 7.5.0-1) 7.5.0
reproduce:
        # save the attached .config to linux build tree
        make ARCH=i386 

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

Note: the linux-review/Wei-Yang/x86-mm-Remove-second-argument-of-split_mem_range/20191207-061345 HEAD 7f535395f79354bfa29cca182dd203525bcb4237 builds fine.
      It only hurts bisectibility.

All errors (new ones prefixed by >>):

   arch/x86/mm/init.c: In function 'save_mr':
>> arch/x86/mm/init.c:265:6: error: 'start_pfn' undeclared (first use in this function); did you mean 'start'?
     if (start_pfn < end_pfn) {
         ^~~~~~~~~
         start
   arch/x86/mm/init.c:265:6: note: each undeclared identifier is reported only once for each function it appears in
>> arch/x86/mm/init.c:265:18: error: 'end_pfn' undeclared (first use in this function); did you mean 'pgd_pfn'?
     if (start_pfn < end_pfn) {
                     ^~~~~~~
                     pgd_pfn

vim +265 arch/x86/mm/init.c

f765090a2617b8 Pekka Enberg 2009-03-05  260  
dc9dd5cc854cde Jan Beulich  2009-03-12  261  static int __meminit save_mr(struct map_range *mr, int nr_range,
51c6d529efdc86 Wei Yang     2019-12-05  262  			     unsigned long start, unsigned long end,
f765090a2617b8 Pekka Enberg 2009-03-05  263  			     unsigned long page_size_mask)
f765090a2617b8 Pekka Enberg 2009-03-05  264  {
f765090a2617b8 Pekka Enberg 2009-03-05 @265  	if (start_pfn < end_pfn) {
f765090a2617b8 Pekka Enberg 2009-03-05  266  		if (nr_range >= NR_RANGE_MR)
f765090a2617b8 Pekka Enberg 2009-03-05  267  			panic("run out of range for init_memory_mapping\n");
51c6d529efdc86 Wei Yang     2019-12-05  268  		mr[nr_range].start = start_pfn;
51c6d529efdc86 Wei Yang     2019-12-05  269  		mr[nr_range].end   = end_pfn;
f765090a2617b8 Pekka Enberg 2009-03-05  270  		mr[nr_range].page_size_mask = page_size_mask;
f765090a2617b8 Pekka Enberg 2009-03-05  271  		nr_range++;
f765090a2617b8 Pekka Enberg 2009-03-05  272  	}
f765090a2617b8 Pekka Enberg 2009-03-05  273  
f765090a2617b8 Pekka Enberg 2009-03-05  274  	return nr_range;
f765090a2617b8 Pekka Enberg 2009-03-05  275  }
f765090a2617b8 Pekka Enberg 2009-03-05  276  

:::::: The code at line 265 was first introduced by commit
:::::: f765090a2617b8d9cb73b71e0aa850c29460d8be x86: move init_memory_mapping() to common mm/init.c

:::::: TO: Pekka Enberg <penberg@cs.helsinki.fi>
:::::: CC: Ingo Molnar <mingo@elte.hu>

---
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