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>

1 files changed, 29 insertions, 31 deletions

diff --git a/mm/interval_tree.c b/mm/interval_tree.c
index 7dc565660e5..4ab7b9ec3a5 100644
--- a/mm/interval_tree.c
+++ b/mm/interval_tree.c
@@ -8,40 +8,38 @@
 
 #include <linux/mm.h>
 #include <linux/fs.h>
+#include <linux/interval_tree_generic.h>
 
-#define ITSTRUCT   struct vm_area_struct
-#define ITRB       shared.linear.rb
-#define ITTYPE     unsigned long
-#define ITSUBTREE  shared.linear.rb_subtree_last
-#define ITSTART(n) ((n)->vm_pgoff)
-#define ITLAST(n)  ((n)->vm_pgoff + \
-		    (((n)->vm_end - (n)->vm_start) >> PAGE_SHIFT) - 1)
-#define ITSTATIC
-#define ITPREFIX   vma_interval_tree
-
-#include <linux/interval_tree_tmpl.h>
-
-/* Insert old immediately after vma in the interval tree */
-void vma_interval_tree_add(struct vm_area_struct *vma,
-			   struct vm_area_struct *old,
-			   struct address_space *mapping)
+static inline unsigned long vma_start_pgoff(struct vm_area_struct *v)
+{
+	return v->vm_pgoff;
+}
+
+static inline unsigned long vma_last_pgoff(struct vm_area_struct *v)
+{
+	return v->vm_pgoff + ((v->vm_end - v->vm_start) >> PAGE_SHIFT) - 1;
+}
+
+INTERVAL_TREE_DEFINE(struct vm_area_struct, shared.linear.rb,
+		     unsigned long, shared.linear.rb_subtree_last,
+		     vma_start_pgoff, vma_last_pgoff,, vma_interval_tree)
+
+/* Insert node immediately after prev in the interval tree */
+void vma_interval_tree_insert_after(struct vm_area_struct *node,
+				    struct vm_area_struct *prev,
+				    struct rb_root *root)
 {
 	struct rb_node **link;
 	struct vm_area_struct *parent;
-	unsigned long last;
-
-	if (unlikely(vma->vm_flags & VM_NONLINEAR)) {
-		list_add(&vma->shared.nonlinear, &old->shared.nonlinear);
-		return;
-	}
+	unsigned long last = vma_last_pgoff(node);
 
-	last = ITLAST(vma);
+	VM_BUG_ON(vma_start_pgoff(node) != vma_start_pgoff(prev));
 
-	if (!old->shared.linear.rb.rb_right) {
-		parent = old;
-		link = &old->shared.linear.rb.rb_right;
+	if (!prev->shared.linear.rb.rb_right) {
+		parent = prev;
+		link = &prev->shared.linear.rb.rb_right;
 	} else {
-		parent = rb_entry(old->shared.linear.rb.rb_right,
+		parent = rb_entry(prev->shared.linear.rb.rb_right,
 				  struct vm_area_struct, shared.linear.rb);
 		if (parent->shared.linear.rb_subtree_last < last)
 			parent->shared.linear.rb_subtree_last = last;
@@ -54,8 +52,8 @@ void vma_interval_tree_add(struct vm_area_struct *vma,
 		link = &parent->shared.linear.rb.rb_left;
 	}
 
-	vma->shared.linear.rb_subtree_last = last;
-	rb_link_node(&vma->shared.linear.rb, &parent->shared.linear.rb, link);
-	rb_insert_augmented(&vma->shared.linear.rb, &mapping->i_mmap,
-			    &vma_interval_tree_augment_callbacks);
+	node->shared.linear.rb_subtree_last = last;
+	rb_link_node(&node->shared.linear.rb, &parent->shared.linear.rb, link);
+	rb_insert_augmented(&node->shared.linear.rb, root,
+			    &vma_interval_tree_augment);
 }