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authorJens Axboe <axboe@kernel.dk>2012-07-30 09:03:10 +0200
committerJens Axboe <axboe@kernel.dk>2012-07-30 09:03:10 +0200
commit72ea1f74fcdf874cca6d2c0962379523bbd99e2c (patch)
tree4c67be6c73356086ff44ef1b8b1c9479702689ca /include/linux/swapops.h
parentb1af9be5ef77898c05667bb9dbf3b180d91d3292 (diff)
parenta73ff3231df59a4b92ccd0dd4e73897c5822489b (diff)
Merge branch 'for-jens' of git://git.drbd.org/linux-drbd into for-3.6/drivers
Diffstat (limited to 'include/linux/swapops.h')
-rw-r--r--include/linux/swapops.h8
1 files changed, 5 insertions, 3 deletions
diff --git a/include/linux/swapops.h b/include/linux/swapops.h
index 792d16d9cbc..47ead515c81 100644
--- 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)
/*