Re: [PATCH] mm: skip less than check for MAX_NR_ZONES

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

Hi,

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/alexs-kernel-org/mm-skip-less-than-check-for-MAX_NR_ZONES/20240819-111528
base:   https://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm.git mm-everything
patch link:    https://lore.kernel.org/r/20240819031911.367900-1-alexs%40kernel.org
patch subject: [PATCH] mm: skip less than check for MAX_NR_ZONES
config: openrisc-allnoconfig (https://download.01.org/0day-ci/archive/20240819/202408191739.UV22bvQV-lkp@intel.com/config)
compiler: or1k-linux-gcc (GCC) 14.1.0
reproduce (this is a W=1 build): (https://download.01.org/0day-ci/archive/20240819/202408191739.UV22bvQV-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/202408191739.UV22bvQV-lkp@intel.com/

All errors (new ones prefixed by >>):

   In file included from include/linux/mm_types.h:18,
                    from include/linux/sched/signal.h:14,
                    from include/linux/ptrace.h:7,
                    from arch/openrisc/kernel/asm-offsets.c:28:
>> include/linux/page-flags-layout.h:17:20: error: token "=" is not valid in preprocessor expressions
      17 | #elif MAX_NR_ZONES = 2
         |                    ^
   make[3]: *** [scripts/Makefile.build:117: arch/openrisc/kernel/asm-offsets.s] Error 1
   make[3]: Target 'prepare' not remade because of errors.
   make[2]: *** [Makefile:1193: prepare0] Error 2
   make[2]: Target 'prepare' not remade because of errors.
   make[1]: *** [Makefile:224: __sub-make] Error 2
   make[1]: Target 'prepare' not remade because of errors.
   make: *** [Makefile:224: __sub-make] Error 2
   make: Target 'prepare' not remade because of errors.


vim +17 include/linux/page-flags-layout.h

     7	
     8	/*
     9	 * When a memory allocation must conform to specific limitations (such
    10	 * as being suitable for DMA) the caller will pass in hints to the
    11	 * allocator in the gfp_mask, in the zone modifier bits.  These bits
    12	 * are used to select a priority ordered list of memory zones which
    13	 * match the requested limits. See gfp_zone() in include/linux/gfp.h
    14	 */
    15	#if MAX_NR_ZONES < 2
    16	#define ZONES_SHIFT 0
  > 17	#elif MAX_NR_ZONES = 2
    18	#define ZONES_SHIFT 1
    19	#elif MAX_NR_ZONES <= 4
    20	#define ZONES_SHIFT 2
    21	#elif MAX_NR_ZONES <= 8
    22	#define ZONES_SHIFT 3
    23	#else
    24	#error ZONES_SHIFT "Too many zones configured"
    25	#endif
    26	

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