Merge tag 'kvm-arm-for-4.6-rc4' of git://git.kernel.org/pub/scm/linux/kernel/git...

[deliverable/linux.git] / arch / s390 / mm / gup.c

diff --git a/arch/s390/mm/gup.c b/arch/s390/mm/gup.c
index 49a1c84ed2663fadeadb2bc1b8548814d9cab012..a8a6765f1a519501b0f28bf7ca3a318d0b47f9a1 100644 (file)
--- a/arch/s390/mm/gup.c
+++ b/arch/s390/mm/gup.c
@@ -20,9 +20,9 @@
 static inline int gup_pte_range(pmd_t *pmdp, pmd_t pmd, unsigned long addr,
                unsigned long end, int write, struct page **pages, int *nr)
 {
+       struct page *head, *page;
        unsigned long mask;
        pte_t *ptep, pte;
-       struct page *page;
 
        mask = (write ? _PAGE_PROTECT : 0) | _PAGE_INVALID | _PAGE_SPECIAL;
 
@@ -37,12 +37,14 @@ static inline int gup_pte_range(pmd_t *pmdp, pmd_t pmd, unsigned long addr,
                        return 0;
                VM_BUG_ON(!pfn_valid(pte_pfn(pte)));
                page = pte_page(pte);
-               if (!page_cache_get_speculative(page))
+               head = compound_head(page);
+               if (!page_cache_get_speculative(head))
                        return 0;
                if (unlikely(pte_val(pte) != pte_val(*ptep))) {
-                       put_page(page);
+                       put_page(head);
                        return 0;
                }
+               VM_BUG_ON_PAGE(compound_head(page) != head, page);
                pages[*nr] = page;
                (*nr)++;