source: GPL/trunk/include/linux/rbtree.h

Last change on this file was 679, checked in by David Azarewicz, 4 years ago

Merge changes from Paul's uniaud32next branch.
File size: 5.1 KB
Line 
1/* SPDX-License-Identifier: GPL-2.0-or-later */
2/*
3 Red Black Trees
4 (C) 1999 Andrea Arcangeli <andrea@suse.de>
5
6
7 linux/include/linux/rbtree.h
8
9 To use rbtrees you'll have to implement your own insert and search cores.
10 This will avoid us to use callbacks and to drop drammatically performances.
11 I know it's not the cleaner way, but in C (not in C++) to get
12 performances and genericity...
13
14 See Documentation/core-api/rbtree.rst for documentation and samples.
15*/
16/* from 5.10.10 */
17
18#ifndef _LINUX_RBTREE_H
19#define _LINUX_RBTREE_H
20
21#include <linux/kernel.h>
22#include <linux/stddef.h>
23//#include <linux/rcupdate.h>
24
25struct rb_node {
26 unsigned long __rb_parent_color;
27 struct rb_node *rb_right;
28 struct rb_node *rb_left;
29} /*__attribute__((aligned(sizeof(long))))*/;
30 /* The alignment might seem pointless, but allegedly CRIS needs it */
31
32struct rb_root {
33 struct rb_node *rb_node;
34};
35
36#define rb_parent(r) ((struct rb_node *)((r)->__rb_parent_color & ~3))
37
38#define RB_ROOT (struct rb_root) { NULL, }
39#define rb_entry(ptr, type, member) container_of(ptr, type, member)
40
41#define RB_EMPTY_ROOT(root) (READ_ONCE((root)->rb_node) == NULL)
42
43/* 'empty' nodes are nodes that are known not to be inserted in an rbtree */
44#define RB_EMPTY_NODE(node) \
45 ((node)->__rb_parent_color == (unsigned long)(node))
46#define RB_CLEAR_NODE(node) \
47 ((node)->__rb_parent_color = (unsigned long)(node))
48
49
50extern void rb_insert_color(struct rb_node *, struct rb_root *);
51extern void rb_erase(struct rb_node *, struct rb_root *);
52
53
54/* Find logical next and previous nodes in a tree */
55extern struct rb_node *rb_next(const struct rb_node *);
56extern struct rb_node *rb_prev(const struct rb_node *);
57extern struct rb_node *rb_first(const struct rb_root *);
58extern struct rb_node *rb_last(const struct rb_root *);
59
60/* Postorder iteration - always visit the parent after its children */
61extern struct rb_node *rb_first_postorder(const struct rb_root *);
62extern struct rb_node *rb_next_postorder(const struct rb_node *);
63
64/* Fast replacement of a single node without remove/rebalance/add/rebalance */
65extern void rb_replace_node(struct rb_node *victim, struct rb_node *new,
66 struct rb_root *root);
67extern void rb_replace_node_rcu(struct rb_node *victim, struct rb_node *new,
68 struct rb_root *root);
69
70static inline void rb_link_node(struct rb_node *node, struct rb_node *parent,
71 struct rb_node **rb_link)
72{
73 node->__rb_parent_color = (unsigned long)parent;
74 node->rb_left = node->rb_right = NULL;
75
76 *rb_link = node;
77}
78
79#ifndef TARGET_OS2
80static inline void rb_link_node_rcu(struct rb_node *node, struct rb_node *parent,
81 struct rb_node **rb_link)
82{
83 node->__rb_parent_color = (unsigned long)parent;
84 node->rb_left = node->rb_right = NULL;
85
86 rcu_assign_pointer(*rb_link, node);
87}
88#endif
89
90#define rb_entry_safe(ptr, type, member) \
91 ({ typeof(ptr) ____ptr = (ptr); \
92 ____ptr ? rb_entry(____ptr, type, member) : NULL; \
93 })
94
95/**
96 * rbtree_postorder_for_each_entry_safe - iterate in post-order over rb_root of
97 * given type allowing the backing memory of @pos to be invalidated
98 *
99 * @pos: the 'type *' to use as a loop cursor.
100 * @n: another 'type *' to use as temporary storage
101 * @root: 'rb_root *' of the rbtree.
102 * @field: the name of the rb_node field within 'type'.
103 *
104 * rbtree_postorder_for_each_entry_safe() provides a similar guarantee as
105 * list_for_each_entry_safe() and allows the iteration to continue independent
106 * of changes to @pos by the body of the loop.
107 *
108 * Note, however, that it cannot handle other modifications that re-order the
109 * rbtree it is iterating over. This includes calling rb_erase() on @pos, as
110 * rb_erase() may rebalance the tree, causing us to miss some nodes.
111 */
112#define rbtree_postorder_for_each_entry_safe(pos, n, root, field) \
113 for (pos = rb_entry_safe(rb_first_postorder(root), typeof(*pos), field); \
114 pos && ({ n = rb_entry_safe(rb_next_postorder(&pos->field), \
115 typeof(*pos), field); 1; }); \
116 pos = n)
117
118/*
119 * Leftmost-cached rbtrees.
120 *
121 * We do not cache the rightmost node based on footprint
122 * size vs number of potential users that could benefit
123 * from O(1) rb_last(). Just not worth it, users that want
124 * this feature can always implement the logic explicitly.
125 * Furthermore, users that want to cache both pointers may
126 * find it a bit asymmetric, but that's ok.
127 */
128struct rb_root_cached {
129 struct rb_root rb_root;
130 struct rb_node *rb_leftmost;
131};
132
133#define RB_ROOT_CACHED (struct rb_root_cached) { {NULL, }, NULL }
134
135/* Same as rb_first(), but O(1) */
136#define rb_first_cached(root) (root)->rb_leftmost
137
138static inline void rb_insert_color_cached(struct rb_node *node,
139 struct rb_root_cached *root,
140 bool leftmost)
141{
142 if (leftmost)
143 root->rb_leftmost = node;
144 rb_insert_color(node, &root->rb_root);
145}
146
147static inline void rb_erase_cached(struct rb_node *node,
148 struct rb_root_cached *root)
149{
150 if (root->rb_leftmost == node)
151 root->rb_leftmost = rb_next(node);
152 rb_erase(node, &root->rb_root);
153}
154
155static inline void rb_replace_node_cached(struct rb_node *victim,
156 struct rb_node *new,
157 struct rb_root_cached *root)
158{
159 if (root->rb_leftmost == victim)
160 root->rb_leftmost = new;
161 rb_replace_node(victim, new, &root->rb_root);
162}
163
164#endif /* _LINUX_RBTREE_H */
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