swap: fix shmem swapping when more than 8 areas

[platform/adaptation/renesas_rcar/renesas_kernel.git] / include / linux / swapops.h

diff --git a/include/linux/swapops.h b/include/linux/swapops.h
index 792d16d..47ead51 100644 (file)
--- a/include/linux/swapops.h
+++ b/include/linux/swapops.h
@@ -9,13 +9,15 @@
  * get good packing density in that tree, so the index should be dense in
  * the low-order bits.
  *
- * We arrange the `type' and `offset' fields so that `type' is at the five
+ * We arrange the `type' and `offset' fields so that `type' is at the seven
  * high-order bits of the swp_entry_t and `offset' is right-aligned in the
- * remaining bits.
+ * remaining bits.  Although `type' itself needs only five bits, we allow for
+ * shmem/tmpfs to shift it all up a further two bits: see swp_to_radix_entry().
  *
  * swp_entry_t's are *never* stored anywhere in their arch-dependent format.
  */
-#define SWP_TYPE_SHIFT(e)      (sizeof(e.val) * 8 - MAX_SWAPFILES_SHIFT)
+#define SWP_TYPE_SHIFT(e)      ((sizeof(e.val) * 8) - \
+                       (MAX_SWAPFILES_SHIFT + RADIX_TREE_EXCEPTIONAL_SHIFT))
 #define SWP_OFFSET_MASK(e)     ((1UL << SWP_TYPE_SHIFT(e)) - 1)
 
 /*