[davidhildenbrand:single_zone 4/4] drivers/base/memory.c:648:14: warning: no previous prototype for 'early_node_zone_for_memory_block'

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

tree:   git://github.com/davidhildenbrand/linux single_zone
head:   176a3d535903312944f7489127f520c5494bc810
commit: 176a3d535903312944f7489127f520c5494bc810 [4/4] tmp
config: x86_64-allyesconfig (https://download.01.org/0day-ci/archive/20220128/202201280300.xX8fHtiK-lkp@intel.com/config)
compiler: gcc-9 (Debian 9.3.0-22) 9.3.0
reproduce (this is a W=1 build):
        # https://github.com/davidhildenbrand/linux/commit/176a3d535903312944f7489127f520c5494bc810
        git remote add davidhildenbrand git://github.com/davidhildenbrand/linux
        git fetch --no-tags davidhildenbrand single_zone
        git checkout 176a3d535903312944f7489127f520c5494bc810
        # save the config file to linux build tree
        mkdir build_dir
        make W=1 O=build_dir ARCH=x86_64 SHELL=/bin/bash drivers/

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

All warnings (new ones prefixed by >>):

>> drivers/base/memory.c:648:14: warning: no previous prototype for 'early_node_zone_for_memory_block' [-Wmissing-prototypes]
     648 | struct zone *early_node_zone_for_memory_block(int nid, struct memory_block *mem)
         |              ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~


vim +/early_node_zone_for_memory_block +648 drivers/base/memory.c

   647	
 > 648	struct zone *early_node_zone_for_memory_block(int nid, struct memory_block *mem)
   649	{
   650		const unsigned long start_pfn = section_nr_to_pfn(mem->start_section_nr);
   651		const unsigned long nr_pages = PAGES_PER_SECTION * sections_per_block;
   652	
   653		struct zone *zone, *matching_zone = NULL;
   654		pg_data_t *pgdat = NODE_DATA(nid);
   655		int i;
   656	
   657		/*
   658		 * This logic only works for early memory, when the applicable zones
   659		 * already span the memory block. We don't expect overlapping zones on
   660		 * a single node for early memory. So if we're told that some pfns
   661		 * of a node fall into this memory block, we can assume that all node
   662		 * zones that intersect with the memory block are actually applicable.
   663		 * No need to look at the memmap.
   664		 *
   665		 * Memory hot(un)plug updates the zone manually after memory
   666		 * onlinig/offlining succeed.
   667		 */
   668		for (i = 0; i < MAX_NR_ZONES; i++) {
   669			zone = pgdat->node_zones + i;
   670			if (!populated_zone(zone))
   671				continue;
   672			if (!zone_intersects(zone, start_pfn, nr_pages))
   673				continue;
   674			if (!matching_zone) {
   675				matching_zone = zone;
   676				continue;
   677			}
   678			/* Spans multiple zones ... */
   679			matching_zone = NULL;
   680			break;
   681		}
   682		return matching_zone;
   683	}
   684	

---
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