[PATCH] mm: ia64 use expand_upwards

ia64 has expand_backing_store function for growing its Register Backing Store
vma upwards.  But more complete code for this purpose is found in the
CONFIG_STACK_GROWSUP part of mm/mmap.c.  Uglify its #ifdefs further to provide
expand_upwards for ia64 as well as expand_stack for parisc.

The Register Backing Store vma should be marked VM_ACCOUNT.  Implement the
intention of growing it only a page at a time, instead of passing an address
outside of the vma to handle_mm_fault, with unknown consequences.

Signed-off-by: Hugh Dickins <hugh@veritas.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>

1 files changed, 14 insertions, 3 deletions

diff --git a/mm/mmap.c b/mm/mmap.c
index c43b2845700..d931d7e49ac 100644
--- a/mm/mmap.c
+++ b/mm/mmap.c
@@ -1508,11 +1508,15 @@ static int acct_stack_growth(struct vm_area_struct * vma, unsigned long size, un
 	return 0;
 }
 
-#ifdef CONFIG_STACK_GROWSUP
+#if defined(CONFIG_STACK_GROWSUP) || defined(CONFIG_IA64)
 /*
- * vma is the first one with address > vma->vm_end.  Have to extend vma.
+ * PA-RISC uses this for its stack; IA64 for its Register Backing Store.
+ * vma is the last one with address > vma->vm_end.  Have to extend vma.
  */
-int expand_stack(struct vm_area_struct * vma, unsigned long address)
+#ifdef CONFIG_STACK_GROWSUP
+static inline
+#endif
+int expand_upwards(struct vm_area_struct *vma, unsigned long address)
 {
 	int error;
 
@@ -1550,6 +1554,13 @@ int expand_stack(struct vm_area_struct * vma, unsigned long address)
 	anon_vma_unlock(vma);
 	return error;
 }
+#endif /* CONFIG_STACK_GROWSUP || CONFIG_IA64 */
+
+#ifdef CONFIG_STACK_GROWSUP
+int expand_stack(struct vm_area_struct *vma, unsigned long address)
+{
+	return expand_upwards(vma, address);
+}
 
 struct vm_area_struct *
 find_extend_vma(struct mm_struct *mm, unsigned long addr)