Don't lock guardpage if the stack is growing up

[linux-flexiantxendom0-natty.git] / mm / memory.c

diff --git a/mm/memory.c b/mm/memory.c
index 7dbff6b..e5bd2d2 100644 (file)
--- a/mm/memory.c
+++ b/mm/memory.c
@@ -1412,9 +1412,8 @@ no_page_table:
 
 static inline int stack_guard_page(struct vm_area_struct *vma, unsigned long addr)
 {
-       return (vma->vm_flags & VM_GROWSDOWN) &&
-               (vma->vm_start == addr) &&
-               !vma_stack_continue(vma->vm_prev, addr);
+       return stack_guard_page_start(vma, addr) ||
+              stack_guard_page_end(vma, addr+PAGE_SIZE);
 }
 
 int __get_user_pages(struct task_struct *tsk, struct mm_struct *mm,
@@ -1502,12 +1501,6 @@ int __get_user_pages(struct task_struct *tsk, struct mm_struct *mm,
                        continue;
                }
 
-               /*
-                * For mlock, just skip the stack guard page.
-                */
-               if ((gup_flags & FOLL_MLOCK) && stack_guard_page(vma, start))
-                       goto next_page;
-
                do {
                        struct page *page;
                        unsigned int foll_flags = gup_flags;
@@ -1524,6 +1517,11 @@ int __get_user_pages(struct task_struct *tsk, struct mm_struct *mm,
                                int ret;
                                unsigned int fault_flags = 0;
 
+                               /* For mlock, just skip the stack guard page. */
+                               if (foll_flags & FOLL_MLOCK) {
+                                       if (stack_guard_page(vma, start))
+                                               goto next_page;
+                               }
                                if (foll_flags & FOLL_WRITE)
                                        fault_flags |= FAULT_FLAG_WRITE;
                                if (nonblocking)