From: Hugh Dickins hughd@google.com Subject: mm: page_vma_mapped_walk(): settle PageHuge on entry

page_vma_mapped_walk() cleanup: get the hugetlbfs PageHuge case out of the way at the start, so no need to worry about it later.

Link: https://lkml.kernel.org/r/e31a483c-6d73-a6bb-26c5-43c3b880a2@google.com Signed-off-by: Hugh Dickins hughd@google.com Acked-by: Kirill A. Shutemov kirill.shutemov@linux.intel.com Reviewed-by: Peter Xu peterx@redhat.com Cc: Alistair Popple apopple@nvidia.com Cc: "Kirill A. Shutemov" kirill.shutemov@linux.intel.com Cc: Matthew Wilcox willy@infradead.org Cc: Ralph Campbell rcampbell@nvidia.com Cc: Wang Yugui wangyugui@e16-tech.com Cc: Will Deacon will@kernel.org Cc: Yang Shi shy828301@gmail.com Cc: Zi Yan ziy@nvidia.com Cc: stable@vger.kernel.org Signed-off-by: Andrew Morton akpm@linux-foundation.org ---

mm/page_vma_mapped.c | 12 ++++++++---- 1 file changed, 8 insertions(+), 4 deletions(-)

--- a/mm/page_vma_mapped.c~mm-page_vma_mapped_walk-settle-pagehuge-on-entry +++ a/mm/page_vma_mapped.c @@ -153,10 +153,11 @@ bool page_vma_mapped_walk(struct page_vm if (pvmw->pmd && !pvmw->pte) return not_found(pvmw);

- if (pvmw->pte) - goto next_pte; - if (unlikely(PageHuge(page))) { + /* The only possible mapping was handled on last iteration */ + if (pvmw->pte) + return not_found(pvmw); + /* when pud is not present, pte will be NULL */ pvmw->pte = huge_pte_offset(mm, pvmw->address, page_size(page)); if (!pvmw->pte) @@ -168,6 +169,9 @@ bool page_vma_mapped_walk(struct page_vm return not_found(pvmw); return true; } + + if (pvmw->pte) + goto next_pte; restart: pgd = pgd_offset(mm, pvmw->address); if (!pgd_present(*pgd)) @@ -233,7 +237,7 @@ restart: return true; next_pte: /* Seek to next pte only makes sense for THP */ - if (!PageTransHuge(page) || PageHuge(page)) + if (!PageTransHuge(page)) return not_found(pvmw); end = vma_address_end(page, pvmw->vma); do { _