releases/3.0.33/um-fix-__swp_type.patch

   1 From 2b76ebaa728f8a3967c52aa189261c72fe56a6f1 Mon Sep 17 00:00:00 2001
   2 From: Richard Weinberger <richard@nod.at>
   3 Date: Sat, 14 Apr 2012 17:46:01 +0200
   4 Subject: um: Fix __swp_type()
   5
   6 From: Richard Weinberger <richard@nod.at>
   7
   8 commit 2b76ebaa728f8a3967c52aa189261c72fe56a6f1 upstream.
   9
  10 The current __swp_type() function uses a too small bitshift.
  11 Using more than one swap files causes bad pages because
  12 the type bits clash with other page flags.
  13
  14 Analyzed-by: Hugh Dickins <hughd@google.com>
  15 Signed-off-by: Richard Weinberger <richard@nod.at>
  16 Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
  17
  18 ---
  19  arch/um/include/asm/pgtable.h |    4 ++--
  20  1 file changed, 2 insertions(+), 2 deletions(-)
  21
  22 --- a/arch/um/include/asm/pgtable.h
  23 +++ b/arch/um/include/asm/pgtable.h
  24 @@ -346,11 +346,11 @@ extern pte_t *virt_to_pte(struct mm_stru
  25  #define update_mmu_cache(vma,address,ptep) do ; while (0)
  26
  27  /* Encode and de-code a swap entry */
  28 -#define __swp_type(x)                  (((x).val >> 4) & 0x3f)
  29 +#define __swp_type(x)                  (((x).val >> 5) & 0x1f)
  30  #define __swp_offset(x)                        ((x).val >> 11)
  31
  32  #define __swp_entry(type, offset) \
  33 -       ((swp_entry_t) { ((type) << 4) | ((offset) << 11) })
  34 +       ((swp_entry_t) { ((type) << 5) | ((offset) << 11) })
  35  #define __pte_to_swp_entry(pte) \
  36         ((swp_entry_t) { pte_val(pte_mkuptodate(pte)) })
  37  #define __swp_entry_to_pte(x)          ((pte_t) { (x).val })