Re: [PATCH v2 2/3] mm: rmap: Fix CONT-PTE/PMD size hugetlb issue when migration

[Baolin Wang]

Hi,

On 5/8/2022 8:01 PM, kernel test robot wrote:
> Hi Baolin,
>
> I love your patch! Yet something to improve:
>
> [auto build test ERROR on akpm-mm/mm-everything]
> [also build test ERROR on next-20220506]
> [cannot apply to hnaz-mm/master arm64/for-next/core linus/master v5.18-rc5]
> [If your patch is applied to the wrong git tree, kindly drop us a note.
> And when submitting patch, we suggest to use '--base' as documented in
> https://git-scm.com/docs/git-format-patch]
>
> url:    https://github.com/intel-lab-lkp/linux/commits/Baolin-Wang/Fix-CONT-PTE-PMD-size-hugetlb-issue-when-unmapping-or-migrating/20220508-174036
> base:   https://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm.git mm-everything
> config: x86_64-randconfig-a013 (https://download.01.org/0day-ci/archive/20220508/202205081910.mStoC5rj-lkp@xxxxxxxxx/config)
> compiler: gcc-11 (Debian 11.2.0-20) 11.2.0
> reproduce (this is a W=1 build):
>          # https://github.com/intel-lab-lkp/linux/commit/907981b27213707fdb2f8a24c107d6752a09a773
>          git remote add linux-review https://github.com/intel-lab-lkp/linux
>          git fetch --no-tags linux-review Baolin-Wang/Fix-CONT-PTE-PMD-size-hugetlb-issue-when-unmapping-or-migrating/20220508-174036
>          git checkout 907981b27213707fdb2f8a24c107d6752a09a773
>          # save the config file
>          mkdir build_dir && cp config build_dir/.config
>          make W=1 O=build_dir ARCH=x86_64 SHELL=/bin/bash
>
> If you fix the issue, kindly add following tag as appropriate
> Reported-by: kernel test robot <lkp@xxxxxxxxx>
>
> All errors (new ones prefixed by >>):
>
>     mm/rmap.c: In function 'try_to_migrate_one':
> > > mm/rmap.c:1931:34: error: implicit declaration of function 'huge_ptep_clear_flush'; did you mean 'ptep_clear_flush'? [-Werror=implicit-function-declaration]
>      1931 |                         pteval = huge_ptep_clear_flush(vma, address, pvmw.pte);
>           |                                  ^~~~~~~~~~~~~~~~~~~~~
>           |                                  ptep_clear_flush
> > > mm/rmap.c:1931:34: error: incompatible types when assigning to type 'pte_t' from type 'int'
> > > mm/rmap.c:2023:41: error: implicit declaration of function 'set_huge_pte_at'; did you mean 'set_huge_swap_pte_at'? [-Werror=implicit-function-declaration]
>      2023 |                                         set_huge_pte_at(mm, address, pvmw.pte, pteval);
>           |                                         ^~~~~~~~~~~~~~~
>           |                                         set_huge_swap_pte_at
>     cc1: some warnings being treated as errors

Thanks for reporting. I think I should add some dummy functions in 
hugetlb.h file if the CONFIG_HUGETLB_PAGE is not selected. I can pass 
the building with below changes and your config file.

diff --git a/include/linux/hugetlb.h b/include/linux/hugetlb.h
index 306d6ef..9f71043 100644
--- a/include/linux/hugetlb.h
+++ b/include/linux/hugetlb.h
@@ -1093,6 +1093,17 @@ static inline void set_huge_swap_pte_at(struct 
mm_struct *mm, unsigned long addr
                                        pte_t *ptep, pte_t pte, 
unsigned long sz)
 {
 }
+
+static inline pte_t huge_ptep_clear_flush(struct vm_area_struct *vma,
+                                         unsigned long addr, pte_t *ptep)
+{
+       return ptep_get(ptep);
+}
+
+static inline void set_huge_pte_at(struct mm_struct *mm, unsigned long 
addr,
+                                  pte_t *ptep, pte_t pte)
+{
+}
 #endif /* CONFIG_HUGETLB_PAGE */