1 files changed, 6 insertions, 3 deletions

diff --git a/arch/x86/mm/gup.c b/arch/x86/mm/gup.c
index 3085f25b4355..007bb06c7504 100644
--- a/arch/x86/mm/gup.c
+++ b/arch/x86/mm/gup.c
@@ -223,14 +223,17 @@ int get_user_pages_fast(unsigned long start, int nr_pages, int write,
                         struct page **pages)
 {
         struct mm_struct *mm = current->mm;
-        unsigned long end = start + (nr_pages << PAGE_SHIFT);
-        unsigned long addr = start;
+        unsigned long addr, len, end;
         unsigned long next;
         pgd_t *pgdp;
         int nr = 0;
 
+        start &= PAGE_MASK;
+        addr = start;
+        len = (unsigned long) nr_pages << PAGE_SHIFT;
+        end = start + len;
         if (unlikely(!access_ok(write ? VERIFY_WRITE : VERIFY_READ,
-                                        start, nr_pages*PAGE_SIZE)))
+                                        start, len)))
                 goto slow_irqon;
 
         /*