um: Fix __swp_type()
commit 2b76ebaa728f8a3967c52aa189261c72fe56a6f1 upstream.
The current __swp_type() function uses a too small bitshift.
Using more than one swap files causes bad pages because
the type bits clash with other page flags.
Analyzed-by: Hugh Dickins <hughd@google.com>
Signed-off-by: Richard Weinberger <richard@nod.at>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
diff --git a/arch/um/include/asm/pgtable.h b/arch/um/include/asm/pgtable.h
index 6a3f984..9a61ee1 100644
--- a/arch/um/include/asm/pgtable.h
+++ b/arch/um/include/asm/pgtable.h
@@ -348,11 +348,11 @@
#define update_mmu_cache(vma,address,ptep) do ; while (0)
/* Encode and de-code a swap entry */
-#define __swp_type(x) (((x).val >> 4) & 0x3f)
+#define __swp_type(x) (((x).val >> 5) & 0x1f)
#define __swp_offset(x) ((x).val >> 11)
#define __swp_entry(type, offset) \
- ((swp_entry_t) { ((type) << 4) | ((offset) << 11) })
+ ((swp_entry_t) { ((type) << 5) | ((offset) << 11) })
#define __pte_to_swp_entry(pte) \
((swp_entry_t) { pte_val(pte_mkuptodate(pte)) })
#define __swp_entry_to_pte(x) ((pte_t) { (x).val })