1 /* SPDX-License-Identifier: GPL-2.0-or-later */
4 (C) 1999 Andrea Arcangeli <andrea@suse.de>
7 linux/include/linux/rbtree.h
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...
14 See Documentation/rbtree.txt for documentation and samples.
17 #ifndef __TOOLS_LINUX_PERF_RBTREE_H
18 #define __TOOLS_LINUX_PERF_RBTREE_H
20 #include <linux/kernel.h>
21 #include <linux/stddef.h>
24 unsigned long __rb_parent_color;
25 struct rb_node *rb_right;
26 struct rb_node *rb_left;
27 } __attribute__((aligned(sizeof(long))));
28 /* The alignment might seem pointless, but allegedly CRIS needs it */
31 struct rb_node *rb_node;
35 * Leftmost-cached rbtrees.
37 * We do not cache the rightmost node based on footprint
38 * size vs number of potential users that could benefit
39 * from O(1) rb_last(). Just not worth it, users that want
40 * this feature can always implement the logic explicitly.
41 * Furthermore, users that want to cache both pointers may
42 * find it a bit asymmetric, but that's ok.
44 struct rb_root_cached {
45 struct rb_root rb_root;
46 struct rb_node *rb_leftmost;
49 #define rb_parent(r) ((struct rb_node *)((r)->__rb_parent_color & ~3))
51 #define RB_ROOT (struct rb_root) { NULL, }
52 #define RB_ROOT_CACHED (struct rb_root_cached) { {NULL, }, NULL }
53 #define rb_entry(ptr, type, member) container_of(ptr, type, member)
55 #define RB_EMPTY_ROOT(root) (READ_ONCE((root)->rb_node) == NULL)
57 /* 'empty' nodes are nodes that are known not to be inserted in an rbtree */
58 #define RB_EMPTY_NODE(node) \
59 ((node)->__rb_parent_color == (unsigned long)(node))
60 #define RB_CLEAR_NODE(node) \
61 ((node)->__rb_parent_color = (unsigned long)(node))
64 extern void rb_insert_color(struct rb_node *, struct rb_root *);
65 extern void rb_erase(struct rb_node *, struct rb_root *);
68 /* Find logical next and previous nodes in a tree */
69 extern struct rb_node *rb_next(const struct rb_node *);
70 extern struct rb_node *rb_prev(const struct rb_node *);
71 extern struct rb_node *rb_first(const struct rb_root *);
72 extern struct rb_node *rb_last(const struct rb_root *);
74 extern void rb_insert_color_cached(struct rb_node *,
75 struct rb_root_cached *, bool);
76 extern void rb_erase_cached(struct rb_node *node, struct rb_root_cached *);
77 /* Same as rb_first(), but O(1) */
78 #define rb_first_cached(root) (root)->rb_leftmost
80 /* Postorder iteration - always visit the parent after its children */
81 extern struct rb_node *rb_first_postorder(const struct rb_root *);
82 extern struct rb_node *rb_next_postorder(const struct rb_node *);
84 /* Fast replacement of a single node without remove/rebalance/add/rebalance */
85 extern void rb_replace_node(struct rb_node *victim, struct rb_node *new,
86 struct rb_root *root);
87 extern void rb_replace_node_cached(struct rb_node *victim, struct rb_node *new,
88 struct rb_root_cached *root);
90 static inline void rb_link_node(struct rb_node *node, struct rb_node *parent,
91 struct rb_node **rb_link)
93 node->__rb_parent_color = (unsigned long)parent;
94 node->rb_left = node->rb_right = NULL;
99 #define rb_entry_safe(ptr, type, member) \
100 ({ typeof(ptr) ____ptr = (ptr); \
101 ____ptr ? rb_entry(____ptr, type, member) : NULL; \
105 * rbtree_postorder_for_each_entry_safe - iterate in post-order over rb_root of
106 * given type allowing the backing memory of @pos to be invalidated
108 * @pos: the 'type *' to use as a loop cursor.
109 * @n: another 'type *' to use as temporary storage
110 * @root: 'rb_root *' of the rbtree.
111 * @field: the name of the rb_node field within 'type'.
113 * rbtree_postorder_for_each_entry_safe() provides a similar guarantee as
114 * list_for_each_entry_safe() and allows the iteration to continue independent
115 * of changes to @pos by the body of the loop.
117 * Note, however, that it cannot handle other modifications that re-order the
118 * rbtree it is iterating over. This includes calling rb_erase() on @pos, as
119 * rb_erase() may rebalance the tree, causing us to miss some nodes.
121 #define rbtree_postorder_for_each_entry_safe(pos, n, root, field) \
122 for (pos = rb_entry_safe(rb_first_postorder(root), typeof(*pos), field); \
123 pos && ({ n = rb_entry_safe(rb_next_postorder(&pos->field), \
124 typeof(*pos), field); 1; }); \
127 static inline void rb_erase_init(struct rb_node *n, struct rb_root *root)
132 #endif /* __TOOLS_LINUX_PERF_RBTREE_H */