[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>

1 files changed, 3 insertions, 4 deletions

diff --git a/arch/s390/mm/gup.c b/arch/s390/mm/gup.c
index 38e641cdd977..45b405ca2567 100644
--- 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);