xref: /openbmc/linux/mm/interval_tree.c (revision 0c1dcb05)
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 
vma_start_pgoff(struct vm_area_struct * v)13 static inline unsigned long vma_start_pgoff(struct vm_area_struct *v)
14 {
15 	return v->vm_pgoff;
16 }
17 
vma_last_pgoff(struct vm_area_struct * v)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 */
vma_interval_tree_insert_after(struct vm_area_struct * node,struct vm_area_struct * prev,struct rb_root_cached * root)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 
avc_start_pgoff(struct anon_vma_chain * avc)61 static inline unsigned long avc_start_pgoff(struct anon_vma_chain *avc)
62 {
63 	return vma_start_pgoff(avc->vma);
64 }
65 
avc_last_pgoff(struct anon_vma_chain * avc)66 static inline unsigned long avc_last_pgoff(struct anon_vma_chain *avc)
67 {
68 	return vma_last_pgoff(avc->vma);
69 }
70 
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)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 
anon_vma_interval_tree_remove(struct anon_vma_chain * node,struct rb_root_cached * root)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 *
anon_vma_interval_tree_iter_first(struct rb_root_cached * root,unsigned long first,unsigned long last)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 *
anon_vma_interval_tree_iter_next(struct anon_vma_chain * node,unsigned long first,unsigned long last)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
anon_vma_interval_tree_verify(struct anon_vma_chain * node)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