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
13 static inline unsigned long vma_start_pgoff(struct vm_area_struct *v)
14 {
15 return v->vm_pgoff;
16 }
17
18 static inline unsigned long vma_last_pgoff(struct vm_area_struct *v)
19 {
20 return v->vm_pgoff + vma_pages(v) - 1;
21 }
22
23 INTERVAL_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 */
28 void 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
61 static inline unsigned long avc_start_pgoff(struct anon_vma_chain *avc)
62 {
63 return vma_start_pgoff(avc->vma);
64 }
65
66 static inline unsigned long avc_last_pgoff(struct anon_vma_chain *avc)
67 {
68 return vma_last_pgoff(avc->vma);
69 }
70
71 INTERVAL_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
75 void 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
85 void 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
91 struct anon_vma_chain *
92 anon_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
98 struct anon_vma_chain *
99 anon_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
106 void 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
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