Don't lock guardpage if the stack is growing up

[linux-flexiantxendom0-natty.git] / include / linux / mm.h

diff --git a/include/linux/mm.h b/include/linux/mm.h
index 72674d4..f21606b 100644 (file)
--- a/include/linux/mm.h
+++ b/include/linux/mm.h
@@ -994,11 +994,33 @@ int set_page_dirty_lock(struct page *page);
 int clear_page_dirty_for_io(struct page *page);
 
 /* Is the vma a continuation of the stack vma above it? */
-static inline int vma_stack_continue(struct vm_area_struct *vma, unsigned long addr)
+static inline int vma_growsdown(struct vm_area_struct *vma, unsigned long addr)
 {
        return vma && (vma->vm_end == addr) && (vma->vm_flags & VM_GROWSDOWN);
 }
 
+static inline int stack_guard_page_start(struct vm_area_struct *vma,
+                                            unsigned long addr)
+{
+       return (vma->vm_flags & VM_GROWSDOWN) &&
+               (vma->vm_start == addr) &&
+               !vma_growsdown(vma->vm_prev, addr);
+}
+
+/* Is the vma a continuation of the stack vma below it? */
+static inline int vma_growsup(struct vm_area_struct *vma, unsigned long addr)
+{
+       return vma && (vma->vm_start == addr) && (vma->vm_flags & VM_GROWSUP);
+}
+
+static inline int stack_guard_page_end(struct vm_area_struct *vma,
+                                          unsigned long addr)
+{
+       return (vma->vm_flags & VM_GROWSUP) &&
+               (vma->vm_end == addr) &&
+               !vma_growsup(vma->vm_next, addr);
+}
+
 extern unsigned long move_page_tables(struct vm_area_struct *vma,
                unsigned long old_addr, struct vm_area_struct *new_vma,
                unsigned long new_addr, unsigned long len);