[akpm-mm:mm-unstable 313/322] include/linux/huge_mm.h:274:16: error: fields must have a constant size: 'variable length array in structure' extension will never be supported

[Barry Song <21cnbao@gmail.com>]

> tree:   https://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm.git mm-unstable
> head:   f43b3aae94511d62174c3b29239da0dd22d0eeb3
> commit: d4358ee0a075e232114dfec0cd162860cfa2771b [313/322] mm: add per-order mTHP anon_alloc and anon_alloc_fallback counters
> config: powerpc-allyesconfig (https://download.01.org/0day-ci/archive/20240406/202404061754.n8jmZ6s3-lkp@intel.com/config)
> compiler: clang version 19.0.0git (https://github.com/llvm/llvm-project 546dc2245ffc4cccd0b05b58b7a5955e355a3b27)
> reproduce (this is a W=1 build): (https://download.01.org/0day-ci/archive/20240406/202404061754.n8jmZ6s3-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/202404061754.n8jmZ6s3-lkp@intel.com/
> 
> All error/warnings (new ones prefixed by >>):
> 
>    In file included from arch/powerpc/kernel/asm-offsets.c:19:
>    In file included from include/linux/mman.h:5:
>    In file included from include/linux/mm.h:1115:
>>> include/linux/huge_mm.h:274:22: warning: variable length array used [-Wvla]
>      274 |         unsigned long stats[PMD_ORDER + 1][__MTHP_STAT_COUNT];
>          |                             ^~~~~~~~~~~~~

This is amazing. powerpc's PMD_ORDER isn't const. I will
move to alloc_percpu instead of using a static array.

Thanks
Barry