1 /* SPDX-License-Identifier: GPL-2.0 */
2 #ifndef _LINUX_INTERVAL_TREE_H
3 #define _LINUX_INTERVAL_TREE_H
4
5 #include <linux/rbtree.h>
6
7 struct interval_tree_node {
8 struct rb_node rb;
9 unsigned long start; /* Start of interval */
10 unsigned long last; /* Last location _in_ interval */
11 unsigned long __subtree_last;
12 };
13
14 extern void
15 interval_tree_insert(struct interval_tree_node *node,
16 struct rb_root_cached *root);
17
18 extern void
19 interval_tree_remove(struct interval_tree_node *node,
20 struct rb_root_cached *root);
21
22 extern struct interval_tree_node *
23 interval_tree_iter_first(struct rb_root_cached *root,
24 unsigned long start, unsigned long last);
25
26 extern struct interval_tree_node *
27 interval_tree_iter_next(struct interval_tree_node *node,
28 unsigned long start, unsigned long last);
29
30 /**
31 * struct interval_tree_span_iter - Find used and unused spans.
32 * @start_hole: Start of an interval for a hole when is_hole == 1
33 * @last_hole: Inclusive end of an interval for a hole when is_hole == 1
34 * @start_used: Start of a used interval when is_hole == 0
35 * @last_used: Inclusive end of a used interval when is_hole == 0
36 * @is_hole: 0 == used, 1 == is_hole, -1 == done iteration
37 *
38 * This iterator travels over spans in an interval tree. It does not return
39 * nodes but classifies each span as either a hole, where no nodes intersect, or
40 * a used, which is fully covered by nodes. Each iteration step toggles between
41 * hole and used until the entire range is covered. The returned spans always
42 * fully cover the requested range.
43 *
44 * The iterator is greedy, it always returns the largest hole or used possible,
45 * consolidating all consecutive nodes.
46 *
47 * Use interval_tree_span_iter_done() to detect end of iteration.
48 */
49 struct interval_tree_span_iter {
50 /* private: not for use by the caller */
51 struct interval_tree_node *nodes[2];
52 unsigned long first_index;
53 unsigned long last_index;
54
55 /* public: */
56 union {
57 unsigned long start_hole;
58 unsigned long start_used;
59 };
60 union {
61 unsigned long last_hole;
62 unsigned long last_used;
63 };
64 int is_hole;
65 };
66
67 void interval_tree_span_iter_first(struct interval_tree_span_iter *state,
68 struct rb_root_cached *itree,
69 unsigned long first_index,
70 unsigned long last_index);
71 void interval_tree_span_iter_advance(struct interval_tree_span_iter *iter,
72 struct rb_root_cached *itree,
73 unsigned long new_index);
74 void interval_tree_span_iter_next(struct interval_tree_span_iter *state);
75
76 static inline bool
interval_tree_span_iter_done(struct interval_tree_span_iter * state)77 interval_tree_span_iter_done(struct interval_tree_span_iter *state)
78 {
79 return state->is_hole == -1;
80 }
81
82 #define interval_tree_for_each_span(span, itree, first_index, last_index) \
83 for (interval_tree_span_iter_first(span, itree, \
84 first_index, last_index); \
85 !interval_tree_span_iter_done(span); \
86 interval_tree_span_iter_next(span))
87
88 #endif /* _LINUX_INTERVAL_TREE_H */
89