[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>
diff --git a/arch/ia64/mm/fault.c b/arch/ia64/mm/fault.c
index f21b555..af7eb08 100644
--- a/arch/ia64/mm/fault.c
+++ b/arch/ia64/mm/fault.c
@@ -20,32 +20,6 @@
extern void die (char *, struct pt_regs *, long);
/*
- * This routine is analogous to expand_stack() but instead grows the
- * register backing store (which grows towards higher addresses).
- * Since the register backing store is access sequentially, we
- * disallow growing the RBS by more than a page at a time. Note that
- * the VM_GROWSUP flag can be set on any VM area but that's fine
- * because the total process size is still limited by RLIMIT_STACK and
- * RLIMIT_AS.
- */
-static inline long
-expand_backing_store (struct vm_area_struct *vma, unsigned long address)
-{
- unsigned long grow;
-
- grow = PAGE_SIZE >> PAGE_SHIFT;
- if (address - vma->vm_start > current->signal->rlim[RLIMIT_STACK].rlim_cur
- || (((vma->vm_mm->total_vm + grow) << PAGE_SHIFT) > current->signal->rlim[RLIMIT_AS].rlim_cur))
- return -ENOMEM;
- vma->vm_end += PAGE_SIZE;
- vma->vm_mm->total_vm += grow;
- if (vma->vm_flags & VM_LOCKED)
- vma->vm_mm->locked_vm += grow;
- vm_stat_account(vma->vm_mm, vma->vm_flags, vma->vm_file, grow);
- return 0;
-}
-
-/*
* Return TRUE if ADDRESS points at a page in the kernel's mapped segment
* (inside region 5, on ia64) and that page is present.
*/
@@ -185,7 +159,13 @@
if (REGION_NUMBER(address) != REGION_NUMBER(vma->vm_start)
|| REGION_OFFSET(address) >= RGN_MAP_LIMIT)
goto bad_area;
- if (expand_backing_store(vma, address))
+ /*
+ * Since the register backing store is accessed sequentially,
+ * we disallow growing it by more than a page at a time.
+ */
+ if (address > vma->vm_end + PAGE_SIZE - sizeof(long))
+ goto bad_area;
+ if (expand_upwards(vma, address))
goto bad_area;
}
goto good_area;