1 files changed, 112 insertions, 0 deletions

diff --git a/mm/interval_tree.c b/mm/interval_tree.c
new file mode 100644
index 000000000000..4a5822a586e6
--- /dev/null
+++ b/mm/interval_tree.c
@@ -0,0 +1,112 @@
+/*
+ * mm/interval_tree.c - interval tree for mapping->i_mmap
+ *
+ * Copyright (C) 2012, Michel Lespinasse <walken@google.com>
+ *
+ * This file is released under the GPL v2.
+ */
+
+#include <linux/mm.h>
+#include <linux/fs.h>
+#include <linux/rmap.h>
+#include <linux/interval_tree_generic.h>
+
+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 = vma_last_pgoff(node);
+
+        VM_BUG_ON(vma_start_pgoff(node) != vma_start_pgoff(prev));
+
+        if (!prev->shared.linear.rb.rb_right) {
+                parent = prev;
+                link = &prev->shared.linear.rb.rb_right;
+        } else {
+                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;
+                while (parent->shared.linear.rb.rb_left) {
+                        parent = rb_entry(parent->shared.linear.rb.rb_left,
+                                struct vm_area_struct, shared.linear.rb);
+                        if (parent->shared.linear.rb_subtree_last < last)
+                                parent->shared.linear.rb_subtree_last = last;
+                }
+                link = &parent->shared.linear.rb.rb_left;
+        }
+
+        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);
+}
+
+static inline unsigned long avc_start_pgoff(struct anon_vma_chain *avc)
+{
+        return vma_start_pgoff(avc->vma);
+}
+
+static inline unsigned long avc_last_pgoff(struct anon_vma_chain *avc)
+{
+        return vma_last_pgoff(avc->vma);
+}
+
+INTERVAL_TREE_DEFINE(struct anon_vma_chain, rb, unsigned long, rb_subtree_last,
+                     avc_start_pgoff, avc_last_pgoff,
+                     static inline, __anon_vma_interval_tree)
+
+void anon_vma_interval_tree_insert(struct anon_vma_chain *node,
+                                   struct rb_root *root)
+{
+#ifdef CONFIG_DEBUG_VM_RB
+        node->cached_vma_start = avc_start_pgoff(node);
+        node->cached_vma_last = avc_last_pgoff(node);
+#endif
+        __anon_vma_interval_tree_insert(node, root);
+}
+
+void anon_vma_interval_tree_remove(struct anon_vma_chain *node,
+                                   struct rb_root *root)
+{
+        __anon_vma_interval_tree_remove(node, root);
+}
+
+struct anon_vma_chain *
+anon_vma_interval_tree_iter_first(struct rb_root *root,
+                                  unsigned long first, unsigned long last)
+{
+        return __anon_vma_interval_tree_iter_first(root, first, last);
+}
+
+struct anon_vma_chain *
+anon_vma_interval_tree_iter_next(struct anon_vma_chain *node,
+                                 unsigned long first, unsigned long last)
+{
+        return __anon_vma_interval_tree_iter_next(node, first, last);
+}
+
+#ifdef CONFIG_DEBUG_VM_RB
+void anon_vma_interval_tree_verify(struct anon_vma_chain *node)
+{
+        WARN_ON_ONCE(node->cached_vma_start != avc_start_pgoff(node));
+        WARN_ON_ONCE(node->cached_vma_last != avc_last_pgoff(node));
+}
+#endif