On 3/10/21 10:53 AM, Peter Xu wrote:
> want_pmd_share() is undefined with !ARCH_WANT_HUGE_PMD_SHARE since it's put
> by accident into a "#ifdef ARCH_WANT_HUGE_PMD_SHARE" block. Moving it out
> won't work either since vma_shareable() is only defined within the block.
> Define it for !ARCH_WANT_HUGE_PMD_SHARE instead.
>
> Fixes: 5b109cc1cdcc ("hugetlb/userfaultfd: forbid huge pmd sharing when uffd enabled")
That commit id is from Andrew's tree and I don't think it is stable.
There is a different id in the next tree. Not exactly sure how this is
supposed to be handled.
> Cc: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
> Cc: Mike Kravetz <mike.kravetz@xxxxxxxxxx>
> Cc: Axel Rasmussen <axelrasmussen@xxxxxxxxxx>
> Reported-by: Naresh Kamboju <naresh.kamboju@xxxxxxxxxx>
> Tested-by: Naresh Kamboju <naresh.kamboju@xxxxxxxxxx>
> Signed-off-by: Peter Xu <peterx@xxxxxxxxxx>
> ---
> mm/hugetlb.c | 8 +++++---
> 1 file changed, 5 insertions(+), 3 deletions(-)
Thanks Peter,
Not your fault, but that header file is a bit of a mess.
Reviewed-by: Mike Kravetz <mike.kravetz@xxxxxxxxxx>
--
Mike Kravetz
>
> diff --git a/mm/hugetlb.c b/mm/hugetlb.c
> index d58f1456fe27..8dda7e034477 100644
> --- a/mm/hugetlb.c
> +++ b/mm/hugetlb.c
> @@ -5469,9 +5469,6 @@ static bool vma_shareable(struct vm_area_struct *vma, unsigned long addr)
>
> bool want_pmd_share(struct vm_area_struct *vma, unsigned long addr)
> {
> -#ifndef CONFIG_ARCH_WANT_HUGE_PMD_SHARE
> - return false;
> -#endif
> #ifdef CONFIG_USERFAULTFD
> if (uffd_disable_huge_pmd_share(vma))
> return false;
> @@ -5616,6 +5613,11 @@ void adjust_range_if_pmd_sharing_possible(struct vm_area_struct *vma,
> unsigned long *start, unsigned long *end)
> {
> }
> +
> +bool want_pmd_share(struct vm_area_struct *vma, unsigned long addr)
> +{
> + return false;
> +}
> #endif /* CONFIG_ARCH_WANT_HUGE_PMD_SHARE */
>
> #ifdef CONFIG_ARCH_WANT_GENERAL_HUGETLB
>
