folio_zero_user() is defined in mm/memory.c under CONFIG_TRANSPARENT_HUGEPAGE || CONFIG_HUGETLBFS. A subsequent patch will call it from post_alloc_hook() for all user page zeroing, so configs without THP or HUGETLBFS will need a stub.
Add a macro in the #else branch that falls back to clear_user_highpages(), which handles cache aliasing correctly on VIPT architectures and is always available via highmem.h. Without THP/HUGETLBFS, only order-0 user pages are allocated, so the locality optimization in the real folio_zero_user() (zero near the faulting address last) is not needed. Signed-off-by: Michael S. Tsirkin <[email protected]> Assisted-by: Claude:claude-opus-4-6 Assisted-by: cursor-agent:GPT-5.4-xhigh --- include/linux/mm.h | 3 +++ 1 file changed, 3 insertions(+) diff --git a/include/linux/mm.h b/include/linux/mm.h index 5be3d8a8f806..541d36e5e420 100644 --- a/include/linux/mm.h +++ b/include/linux/mm.h @@ -4718,6 +4718,9 @@ static inline bool vma_is_special_huge(const struct vm_area_struct *vma) (vma->vm_flags & (VM_PFNMAP | VM_MIXEDMAP))); } +#else /* !CONFIG_TRANSPARENT_HUGEPAGE && !CONFIG_HUGETLBFS */ +#define folio_zero_user(folio, addr_hint) \ + clear_user_highpages(&(folio)->page, (addr_hint), folio_nr_pages(folio)) #endif /* CONFIG_TRANSPARENT_HUGEPAGE || CONFIG_HUGETLBFS */ #if MAX_NUMNODES > 1 -- MST
