Revert "mm: enlarge stack guard gap"

[mirror_ubuntu-zesty-kernel.git] / include / linux / mm.h

diff --git a/include/linux/mm.h b/include/linux/mm.h
index fbe65ceafb947eef5e3632e7dfa00db7cf541e1f..3978a350e9e435a17a02a57b73a20483edb190ad 100644 (file)
--- a/include/linux/mm.h
+++ b/include/linux/mm.h
@@ -1366,11 +1366,39 @@ int clear_page_dirty_for_io(struct page *page);
 
 int get_cmdline(struct task_struct *task, char *buffer, int buflen);
 
+/* Is the vma a continuation of the stack vma above it? */
+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 bool vma_is_anonymous(struct vm_area_struct *vma)
 {
        return !vma->vm_ops;
 }
 
+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);
+}
+
 int vma_is_stack_for_current(struct vm_area_struct *vma);
 
 extern unsigned long move_page_tables(struct vm_area_struct *vma,
@@ -2111,22 +2139,16 @@ void page_cache_async_readahead(struct address_space *mapping,
                                pgoff_t offset,
                                unsigned long size);
 
-extern unsigned long stack_guard_gap;
 /* Generic expand stack which grows the stack according to GROWS{UP,DOWN} */
 extern int expand_stack(struct vm_area_struct *vma, unsigned long address);
-extern int stack_guard_area(struct vm_area_struct *vma, unsigned long address);
 
 /* CONFIG_STACK_GROWSUP still needs to to grow downwards at some places */
 extern int expand_downwards(struct vm_area_struct *vma,
-               unsigned long address, unsigned long gap);
-unsigned long expandable_stack_area(struct vm_area_struct *vma,
-               unsigned long address, unsigned long *gap);
-
+               unsigned long address);
 #if VM_GROWSUP
-extern int expand_upwards(struct vm_area_struct *vma,
-               unsigned long address, unsigned long gap);
+extern int expand_upwards(struct vm_area_struct *vma, unsigned long address);
 #else
-  #define expand_upwards(vma, address, gap) (0)
+  #define expand_upwards(vma, address) (0)
 #endif
 
 /* Look up the first VMA which satisfies  addr < vm_end,  NULL if none. */