um: Fix __swp_type()

commit 2b76ebaa 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>

arch/um/include/asm/pgtable.h

@@ -346,11 +346,11 @@ extern pte_t *virt_to_pte(struct mm_struct *mm, unsigned long addr);
 #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 })