[android-common:android12-5.10 0/2] include/linux/mmzone.h:1136:13: error: variable 'nid' set but not used

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

Hi Feng,

FYI, the error/warning still remains.

tree:   https://android.googlesource.com/kernel/common android12-5.10
head:   1290154c48656bd1012a837076a0fbe379330eb3
commit: c65b1bd0af076fa5a1da26b9cf780097b14b1543 [0/2] mm/page_alloc: detect allocation forbidden by cpuset and bail out early
config: x86_64-randconfig-016-20260731 (https://download.01.org/0day-ci/archive/20260731/202607312158.dSl1fUDE-lkp@intel.com/config)
compiler: gcc-14 (Debian 14.2.0-19) 14.2.0
reproduce (this is a W=1 build): (https://download.01.org/0day-ci/archive/20260731/202607312158.dSl1fUDE-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/202607312158.dSl1fUDE-lkp@intel.com/

All errors (new ones prefixed by >>):

   In file included from include/linux/gfp.h:6,
                    from include/linux/umh.h:4,
                    from include/linux/kmod.h:9,
                    from include/linux/module.h:16,
                    from lib/test_bitops.c:9:
   include/linux/mmzone.h: In function 'movable_only_nodes':
>> include/linux/mmzone.h:1136:13: error: variable 'nid' set but not used [-Werror=unused-but-set-variable]
    1136 |         int nid;
         |             ^~~
   cc1: all warnings being treated as errors


vim +/nid +1136 include/linux/mmzone.h

  1094	
  1095	/**
  1096	 * for_each_zone_zonelist_nodemask - helper macro to iterate over valid zones in a zonelist at or below a given zone index and within a nodemask
  1097	 * @zone - The current zone in the iterator
  1098	 * @z - The current pointer within zonelist->_zonerefs being iterated
  1099	 * @zlist - The zonelist being iterated
  1100	 * @highidx - The zone index of the highest zone to return
  1101	 * @nodemask - Nodemask allowed by the allocator
  1102	 *
  1103	 * This iterator iterates though all zones at or below a given zone index and
  1104	 * within a given nodemask
  1105	 */
  1106	#define for_each_zone_zonelist_nodemask(zone, z, zlist, highidx, nodemask) \
  1107		for (z = first_zones_zonelist(zlist, highidx, nodemask), zone = zonelist_zone(z);	\
  1108			zone;							\
  1109			z = next_zones_zonelist(++z, highidx, nodemask),	\
  1110				zone = zonelist_zone(z))
  1111	
  1112	#define for_next_zone_zonelist_nodemask(zone, z, highidx, nodemask) \
  1113		for (zone = z->zone;	\
  1114			zone;							\
  1115			z = next_zones_zonelist(++z, highidx, nodemask),	\
  1116				zone = zonelist_zone(z))
  1117	
  1118	
  1119	/**
  1120	 * for_each_zone_zonelist - helper macro to iterate over valid zones in a zonelist at or below a given zone index
  1121	 * @zone - The current zone in the iterator
  1122	 * @z - The current pointer within zonelist->zones being iterated
  1123	 * @zlist - The zonelist being iterated
  1124	 * @highidx - The zone index of the highest zone to return
  1125	 *
  1126	 * This iterator iterates though all zones at or below a given zone index.
  1127	 */
  1128	#define for_each_zone_zonelist(zone, z, zlist, highidx) \
  1129		for_each_zone_zonelist_nodemask(zone, z, zlist, highidx, NULL)
  1130	
  1131	/* Whether the 'nodes' are all movable nodes */
  1132	static inline bool movable_only_nodes(nodemask_t *nodes)
  1133	{
  1134		struct zonelist *zonelist;
  1135		struct zoneref *z;
> 1136		int nid;
  1137	
  1138		if (nodes_empty(*nodes))
  1139			return false;
  1140	
  1141		/*
  1142		 * We can chose arbitrary node from the nodemask to get a
  1143		 * zonelist as they are interlinked. We just need to find
  1144		 * at least one zone that can satisfy kernel allocations.
  1145		 */
  1146		nid = first_node(*nodes);
  1147		zonelist = &NODE_DATA(nid)->node_zonelists[ZONELIST_FALLBACK];
  1148		z = first_zones_zonelist(zonelist, ZONE_NORMAL,	nodes);
  1149		return (!z->zone) ? true : false;
  1150	}
  1151	

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