Re: [linux-next:master 2796/2998] drivers/nvdimm/e820.c:24:12: error: implicit declaration of function 'phys_to_target_node'

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

On Tue, 25 Aug 2020 21:42:38 +0800 kernel test robot <lkp@intel.com> wrote:

> tree:   https://git.kernel.org/pub/scm/linux/kernel/git/next/linux-next.git master
> head:   3a00d3dfd4b68b208ecd5405e676d06c8ad6bb63
> commit: c36f93c29a94b01da6c400033a0cf6ec2d394579 [2796/2998] mm/memory_hotplug: introduce default phys_to_target_node() implementation
> config: x86_64-randconfig-a011-20200825 (attached as .config)
> compiler: clang version 12.0.0 (https://github.com/llvm/llvm-project 77e5a195f818b9ace91f7b12ab948b21d7918238)
> reproduce (this is a W=1 build):
>         wget https://raw.githubusercontent.com/intel/lkp-tests/master/sbin/make.cross -O ~/bin/make.cross
>         chmod +x ~/bin/make.cross
>         # install x86_64 cross compiling tool for clang build
>         # apt-get install binutils-x86-64-linux-gnu
>         git checkout c36f93c29a94b01da6c400033a0cf6ec2d394579
>         # save the attached .config to linux build tree
>         COMPILER_INSTALL_PATH=$HOME/0day COMPILER=clang make.cross ARCH=x86_64 
> 
> If you fix the issue, kindly add following tag as appropriate
> Reported-by: kernel test robot <lkp@intel.com>
> 
> All errors (new ones prefixed by >>):
> 
> >> drivers/nvdimm/e820.c:24:12: error: implicit declaration of function 'phys_to_target_node' [-Werror,-Wimplicit-function-declaration]
>            int nid = phys_to_target_node(res->start);
>                      ^
>    1 error generated.

Let's move the definitions outside CONFIG_MEMORY_HOTPLUG.

--- a/include/linux/memory_hotplug.h~mm-memory_hotplug-introduce-default-phys_to_target_node-implementation-fix
+++ a/include/linux/memory_hotplug.h
@@ -149,20 +149,6 @@ int add_pages(int nid, unsigned long sta
 	      struct mhp_params *params);
 #endif /* ARCH_HAS_ADD_PAGES */
 
-#ifdef CONFIG_NUMA
-extern int memory_add_physaddr_to_nid(u64 start);
-extern int phys_to_target_node(u64 start);
-#else
-static inline int memory_add_physaddr_to_nid(u64 start)
-{
-	return 0;
-}
-static inline int phys_to_target_node(u64 start)
-{
-	return 0;
-}
-#endif
-
 #ifdef CONFIG_HAVE_ARCH_NODEDATA_EXTENSION
 /*
  * For supporting node-hotadd, we have to allocate a new pgdat.
@@ -289,6 +275,20 @@ static inline bool movable_node_is_enabl
 }
 #endif /* ! CONFIG_MEMORY_HOTPLUG */
 
+#ifdef CONFIG_NUMA
+extern int memory_add_physaddr_to_nid(u64 start);
+extern int phys_to_target_node(u64 start);
+#else
+static inline int memory_add_physaddr_to_nid(u64 start)
+{
+	return 0;
+}
+static inline int phys_to_target_node(u64 start)
+{
+	return 0;
+}
+#endif
+
 #if defined(CONFIG_MEMORY_HOTPLUG) || defined(CONFIG_DEFERRED_STRUCT_PAGE_INIT)
 /*
  * pgdat resizing functions
_