1/*
2 * mm/interval_tree.c - interval tree for mapping->i_mmap
3 *
4 * Copyright (C) 2012, Michel Lespinasse <walken@google.com>
5 *
6 * This file is released under the GPL v2.
7 */
8
9#include <linux/mm.h>
10#include <linux/fs.h>
11#include <linux/rmap.h>
12#include <linux/interval_tree_generic.h>
13
14static inline unsigned long vma_start_pgoff(struct vm_area_struct *v)
15{
16	return v->vm_pgoff;
17}
18
19static inline unsigned long vma_last_pgoff(struct vm_area_struct *v)
20{
21	return v->vm_pgoff + ((v->vm_end - v->vm_start) >> PAGE_SHIFT) - 1;
22}
23
24INTERVAL_TREE_DEFINE(struct vm_area_struct, shared.rb,
25		     unsigned long, shared.rb_subtree_last,
26		     vma_start_pgoff, vma_last_pgoff,, vma_interval_tree)
27
28/* Insert node immediately after prev in the interval tree */
29void vma_interval_tree_insert_after(struct vm_area_struct *node,
30				    struct vm_area_struct *prev,
31				    struct rb_root *root)
32{
33	struct rb_node **link;
34	struct vm_area_struct *parent;
35	unsigned long last = vma_last_pgoff(node);
36
37	VM_BUG_ON_VMA(vma_start_pgoff(node) != vma_start_pgoff(prev), node);
38
39	if (!prev->shared.rb.rb_right) {
40		parent = prev;
41		link = &prev->shared.rb.rb_right;
42	} else {
43		parent = rb_entry(prev->shared.rb.rb_right,
44				  struct vm_area_struct, shared.rb);
45		if (parent->shared.rb_subtree_last < last)
46			parent->shared.rb_subtree_last = last;
47		while (parent->shared.rb.rb_left) {
48			parent = rb_entry(parent->shared.rb.rb_left,
49				struct vm_area_struct, shared.rb);
50			if (parent->shared.rb_subtree_last < last)
51				parent->shared.rb_subtree_last = last;
52		}
53		link = &parent->shared.rb.rb_left;
54	}
55
56	node->shared.rb_subtree_last = last;
57	rb_link_node(&node->shared.rb, &parent->shared.rb, link);
58	rb_insert_augmented(&node->shared.rb, root,
59			    &vma_interval_tree_augment);
60}
61
62static inline unsigned long avc_start_pgoff(struct anon_vma_chain *avc)
63{
64	return vma_start_pgoff(avc->vma);
65}
66
67static inline unsigned long avc_last_pgoff(struct anon_vma_chain *avc)
68{
69	return vma_last_pgoff(avc->vma);
70}
71
72INTERVAL_TREE_DEFINE(struct anon_vma_chain, rb, unsigned long, rb_subtree_last,
73		     avc_start_pgoff, avc_last_pgoff,
74		     static inline, __anon_vma_interval_tree)
75
76void anon_vma_interval_tree_insert(struct anon_vma_chain *node,
77				   struct rb_root *root)
78{
79#ifdef CONFIG_DEBUG_VM_RB
80	node->cached_vma_start = avc_start_pgoff(node);
81	node->cached_vma_last = avc_last_pgoff(node);
82#endif
83	__anon_vma_interval_tree_insert(node, root);
84}
85
86void anon_vma_interval_tree_remove(struct anon_vma_chain *node,
87				   struct rb_root *root)
88{
89	__anon_vma_interval_tree_remove(node, root);
90}
91
92struct anon_vma_chain *
93anon_vma_interval_tree_iter_first(struct rb_root *root,
94				  unsigned long first, unsigned long last)
95{
96	return __anon_vma_interval_tree_iter_first(root, first, last);
97}
98
99struct anon_vma_chain *
100anon_vma_interval_tree_iter_next(struct anon_vma_chain *node,
101				 unsigned long first, unsigned long last)
102{
103	return __anon_vma_interval_tree_iter_next(node, first, last);
104}
105
106#ifdef CONFIG_DEBUG_VM_RB
107void anon_vma_interval_tree_verify(struct anon_vma_chain *node)
108{
109	WARN_ON_ONCE(node->cached_vma_start != avc_start_pgoff(node));
110	WARN_ON_ONCE(node->cached_vma_last != avc_last_pgoff(node));
111}
112#endif
113