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") Cc: Andrew Morton <a...@linux-foundation.org> Cc: Mike Kravetz <mike.krav...@oracle.com> Cc: Axel Rasmussen <axelrasmus...@google.com> Reported-by: Naresh Kamboju <naresh.kamb...@linaro.org> Tested-by: Naresh Kamboju <naresh.kamb...@linaro.org> Signed-off-by: Peter Xu <pet...@redhat.com> --- mm/hugetlb.c | 8 +++++--- 1 file changed, 5 insertions(+), 3 deletions(-) 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 -- 2.26.2