1// SPDX-License-Identifier: GPL-2.0-only
2/*
3 * mm/interval_tree.c - interval tree for mapping->i_mmap
4 *
5 * Copyright (C) 2012, Michel Lespinasse <walken@google.com>
6 */
7
8#include <linux/mm.h>
9#include <linux/fs.h>
10#include <linux/rmap.h>
11#include <linux/interval_tree_generic.h>
12
13static inline unsigned long vma_start_pgoff(struct vm_area_struct *v)
14{
15	return v->vm_pgoff;
16}
17
18static inline unsigned long vma_last_pgoff(struct vm_area_struct *v)
19{
20	return v->vm_pgoff + vma_pages(v) - 1;
21}
22
23INTERVAL_TREE_DEFINE(struct vm_area_struct, shared.rb,
24		     unsigned long, shared.rb_subtree_last,
25		     vma_start_pgoff, vma_last_pgoff, /* empty */, vma_interval_tree)
26
27/* Insert node immediately after prev in the interval tree */
28void vma_interval_tree_insert_after(struct vm_area_struct *node,
29				    struct vm_area_struct *prev,
30				    struct rb_root_cached *root)
31{
32	struct rb_node **link;
33	struct vm_area_struct *parent;
34	unsigned long last = vma_last_pgoff(node);
35
36	VM_BUG_ON_VMA(vma_start_pgoff(node) != vma_start_pgoff(prev), node);
37
38	if (!prev->shared.rb.rb_right) {
39		parent = prev;
40		link = &prev->shared.rb.rb_right;
41	} else {
42		parent = rb_entry(prev->shared.rb.rb_right,
43				  struct vm_area_struct, shared.rb);
44		if (parent->shared.rb_subtree_last < last)
45			parent->shared.rb_subtree_last = last;
46		while (parent->shared.rb.rb_left) {
47			parent = rb_entry(parent->shared.rb.rb_left,
48				struct vm_area_struct, shared.rb);
49			if (parent->shared.rb_subtree_last < last)
50				parent->shared.rb_subtree_last = last;
51		}
52		link = &parent->shared.rb.rb_left;
53	}
54
55	node->shared.rb_subtree_last = last;
56	rb_link_node(&node->shared.rb, &parent->shared.rb, link);
57	rb_insert_augmented(&node->shared.rb, &root->rb_root,
58			    &vma_interval_tree_augment);
59}
60
61static inline unsigned long avc_start_pgoff(struct anon_vma_chain *avc)
62{
63	return vma_start_pgoff(avc->vma);
64}
65
66static inline unsigned long avc_last_pgoff(struct anon_vma_chain *avc)
67{
68	return vma_last_pgoff(avc->vma);
69}
70
71INTERVAL_TREE_DEFINE(struct anon_vma_chain, rb, unsigned long, rb_subtree_last,
72		     avc_start_pgoff, avc_last_pgoff,
73		     static inline, __anon_vma_interval_tree)
74
75void anon_vma_interval_tree_insert(struct anon_vma_chain *node,
76				   struct rb_root_cached *root)
77{
78#ifdef CONFIG_DEBUG_VM_RB
79	node->cached_vma_start = avc_start_pgoff(node);
80	node->cached_vma_last = avc_last_pgoff(node);
81#endif
82	__anon_vma_interval_tree_insert(node, root);
83}
84
85void anon_vma_interval_tree_remove(struct anon_vma_chain *node,
86				   struct rb_root_cached *root)
87{
88	__anon_vma_interval_tree_remove(node, root);
89}
90
91struct anon_vma_chain *
92anon_vma_interval_tree_iter_first(struct rb_root_cached *root,
93				  unsigned long first, unsigned long last)
94{
95	return __anon_vma_interval_tree_iter_first(root, first, last);
96}
97
98struct anon_vma_chain *
99anon_vma_interval_tree_iter_next(struct anon_vma_chain *node,
100				 unsigned long first, unsigned long last)
101{
102	return __anon_vma_interval_tree_iter_next(node, first, last);
103}
104
105#ifdef CONFIG_DEBUG_VM_RB
106void anon_vma_interval_tree_verify(struct anon_vma_chain *node)
107{
108	WARN_ON_ONCE(node->cached_vma_start != avc_start_pgoff(node));
109	WARN_ON_ONCE(node->cached_vma_last != avc_last_pgoff(node));
110}
111#endif
112