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-rw-r--r--mm/interval_tree.c111
1 files changed, 111 insertions, 0 deletions
diff --git a/mm/interval_tree.c b/mm/interval_tree.c
new file mode 100644
index 000000000..32e390c42
--- /dev/null
+++ b/mm/interval_tree.c
@@ -0,0 +1,111 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ * mm/interval_tree.c - interval tree for mapping->i_mmap
+ *
+ * Copyright (C) 2012, Michel Lespinasse <walken@google.com>
+ */
+
+#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 + vma_pages(v) - 1;
+}
+
+INTERVAL_TREE_DEFINE(struct vm_area_struct, shared.rb,
+ unsigned long, shared.rb_subtree_last,
+ vma_start_pgoff, vma_last_pgoff, /* empty */, 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_cached *root)
+{
+ struct rb_node **link;
+ struct vm_area_struct *parent;
+ unsigned long last = vma_last_pgoff(node);
+
+ VM_BUG_ON_VMA(vma_start_pgoff(node) != vma_start_pgoff(prev), node);
+
+ if (!prev->shared.rb.rb_right) {
+ parent = prev;
+ link = &prev->shared.rb.rb_right;
+ } else {
+ parent = rb_entry(prev->shared.rb.rb_right,
+ struct vm_area_struct, shared.rb);
+ if (parent->shared.rb_subtree_last < last)
+ parent->shared.rb_subtree_last = last;
+ while (parent->shared.rb.rb_left) {
+ parent = rb_entry(parent->shared.rb.rb_left,
+ struct vm_area_struct, shared.rb);
+ if (parent->shared.rb_subtree_last < last)
+ parent->shared.rb_subtree_last = last;
+ }
+ link = &parent->shared.rb.rb_left;
+ }
+
+ node->shared.rb_subtree_last = last;
+ rb_link_node(&node->shared.rb, &parent->shared.rb, link);
+ rb_insert_augmented(&node->shared.rb, &root->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_cached *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_cached *root)
+{
+ __anon_vma_interval_tree_remove(node, root);
+}
+
+struct anon_vma_chain *
+anon_vma_interval_tree_iter_first(struct rb_root_cached *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