Re: [akpm-mm:mm-new] BUILD REGRESSION 0bffe67ab8a72b3725cc31c4b525709bd3a3e223

[Andrew Morton <akpm@linux-foundation.org>]

On Thu, 10 Sep 2026 05:56:22 +0800 kernel test robot <lkp@intel.com> wrote:

> tree/branch: https://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm.git mm-new
> branch HEAD: 0bffe67ab8a72b3725cc31c4b525709bd3a3e223  mm/swap, PM: hibernate: atomically replace hibernation pin
> 
> Error/Warning (recently discovered and may have been fixed):
> 
>     https://lore.kernel.org/oe-kbuild-all/202609100351.ALNh2KwC-lkp@intel.com
> 
>     include/linux/mmzone.h:1692:10: error: call to undeclared function 'NODE_DATA'; ISO C99 and later do not support implicit function declarations [-Wimplicit-function-declaration]
>     include/linux/mmzone.h:1692:26: error: member reference type 'int' is not a pointer
>     include/linux/mmzone.h:1780:35: error: conflicting types for 'NODE_DATA'
> 
> Error/Warning ids grouped by kconfigs:

Thanks.  That's Muchun's "mm/sparse-vmemmap: switch device DAX to
shared tail vmemmap pages" not liking CONFIG_NUMA=n.

I'll try this nasty thing for now.  Muchun, please make it less nasty!

--- a/include/linux/mmzone.h~mm-sparse-vmemmap-switch-device-dax-to-shared-tail-vmemmap-pages-fix
+++ a/include/linux/mmzone.h
@@ -1687,16 +1687,20 @@ static inline bool zone_is_zone_device(c
 	return zone_idx(zone) == ZONE_DEVICE;
 }
 
+#ifdef CONFIG_NUMA
 static inline struct zone *device_zone(int nid)
 {
 	return &NODE_DATA(nid)->node_zones[ZONE_DEVICE];
 }
+#endif
 #else
 static inline bool zone_is_zone_device(const struct zone *zone)
 {
 	return false;
 }
+#endif
 
+#if !defined(CONFIG_ZONE_DEVICE) && !defined(CONFIG_NUMA)
 static inline struct zone *device_zone(int nid)
 {
 	return NULL;
_