mm: interval tree updates

Update the generic interval tree code that was introduced in "mm: replace
vma prio_tree with an interval tree".

Changes:

- fixed 'endpoing' typo noticed by Andrew Morton

- replaced include/linux/interval_tree_tmpl.h, which was used as a
  template (including it automatically defined the interval tree
  functions) with include/linux/interval_tree_generic.h, which only
  defines a preprocessor macro INTERVAL_TREE_DEFINE(), which itself
  defines the interval tree functions when invoked. Now that is a very
  long macro which is unfortunate, but it does make the usage sites
  (lib/interval_tree.c and mm/interval_tree.c) a bit nicer than previously.

- make use of RB_DECLARE_CALLBACKS() in the INTERVAL_TREE_DEFINE() macro,
  instead of duplicating that code in the interval tree template.

- replaced vma_interval_tree_add(), which was actually handling the
  nonlinear and interval tree cases, with vma_interval_tree_insert_after()
  which handles only the interval tree case and has an API that is more
  consistent with the other interval tree handling functions.
  The nonlinear case is now handled explicitly in kernel/fork.c dup_mmap().

Signed-off-by: Michel Lespinasse <walken@google.com>
Cc: Andrea Arcangeli <aarcange@redhat.com>
Cc: Rik van Riel <riel@redhat.com>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Daniel Santos <daniel.santos@pobox.com>
Cc: Hugh Dickins <hughd@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
diff --git a/lib/interval_tree.c b/lib/interval_tree.c
index 77a793e..e6eb406 100644
--- a/lib/interval_tree.c
+++ b/lib/interval_tree.c
@@ -1,13 +1,10 @@
 #include <linux/init.h>
 #include <linux/interval_tree.h>
+#include <linux/interval_tree_generic.h>
 
-#define ITSTRUCT   struct interval_tree_node
-#define ITRB       rb
-#define ITTYPE     unsigned long
-#define ITSUBTREE  __subtree_last
-#define ITSTART(n) ((n)->start)
-#define ITLAST(n)  ((n)->last)
-#define ITSTATIC
-#define ITPREFIX   interval_tree
+#define START(node) ((node)->start)
+#define LAST(node)  ((node)->last)
 
-#include <linux/interval_tree_tmpl.h>
+INTERVAL_TREE_DEFINE(struct interval_tree_node, rb,
+		     unsigned long, __subtree_last,
+		     START, LAST,, interval_tree)