Re: [PATCH v2 4/4] hugetlb/userfaultfd: Unshare all pmds for hugetlbfs when register wp

[Peter Xu]

On Thu, Feb 18, 2021 at 10:32:00AM -0800, Axel Rasmussen wrote:
> > @@ -1448,6 +1449,9 @@ static int userfaultfd_register(struct userfaultfd_ctx *ctx,
> >                 vma->vm_flags = new_flags;
> >                 vma->vm_userfaultfd_ctx.ctx = ctx;
> >
> > +               if (is_vm_hugetlb_page(vma) && uffd_disable_huge_pmd_share(vma))
> > +                       hugetlb_unshare_all_pmds(vma);
> 
> This line yields the following error, if building with:
> # CONFIG_CMA is not set
> 
> ./fs/userfaultfd.c:1459: undefined reference to `hugetlb_unshare_all_pmds'

Ouch..  Axel, you mean CONFIG_HUGETLBFS rather than CONFIG_CMA, am I right?

-- 
Peter Xu