[S390] fix get_user_pages_fast

The check for the _PAGE_RO bit in get_user_pages_fast for write==1 is
the wrong way around. It must not be set for the fast path.

Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>

diff --git a/arch/s390/mm/gup.c b/arch/s390/mm/gup.c
index 38e641c..45b405c 100644 (file)
--- a/arch/s390/mm/gup.c
+++ b/arch/s390/mm/gup.c
@@ -20,18 +20,17 @@
 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)
 {
-       unsigned long mask, result;
+       unsigned long mask;
        pte_t *ptep, pte;
        struct page *page;
 
-       result = write ? 0 : _PAGE_RO;
-       mask = result | _PAGE_INVALID | _PAGE_SPECIAL;
+       mask = (write ? _PAGE_RO : 0) | _PAGE_INVALID | _PAGE_SPECIAL;
 
        ptep = ((pte_t *) pmd_deref(pmd)) + pte_index(addr);
        do {
                pte = *ptep;
                barrier();
-               if ((pte_val(pte) & mask) != result)
+               if ((pte_val(pte) & mask) != 0)
                        return 0;
                VM_BUG_ON(!pfn_valid(pte_pfn(pte)));
                page = pte_page(pte);