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>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

diff --git a/mm/page_vma_mapped.c b/mm/page_vma_mapped.c
index a6dbf71..7c05046 100644 (file)
--- a/mm/page_vma_mapped.c
+++ b/mm/page_vma_mapped.c
@@ -153,10 +153,11 @@ bool page_vma_mapped_walk(struct page_vma_mapped_walk *pvmw)
        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_vma_mapped_walk *pvmw)
                        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 {