1 // SPDX-License-Identifier: GPL-2.0
2 /*
3 * Range add and subtract
4 */
5 #include <linux/init.h>
6 #include <linux/minmax.h>
7 #include <linux/printk.h>
8 #include <linux/sort.h>
9 #include <linux/string.h>
10 #include <linux/range.h>
11
12 int add_range(struct range *range, int az, int nr_range, u64 start, u64 end)
13 {
14 if (start >= end)
15 return nr_range;
16
17 /* Out of slots: */
18 if (nr_range >= az)
19 return nr_range;
20
21 range[nr_range].start = start;
22 range[nr_range].end = end;
23
24 nr_range++;
25
26 return nr_range;
27 }
28
29 int add_range_with_merge(struct range *range, int az, int nr_range,
30 u64 start, u64 end)
31 {
32 int i;
33
34 if (start >= end)
35 return nr_range;
36
37 /* get new start/end: */
38 for (i = 0; i < nr_range; i++) {
39 u64 common_start, common_end;
40
41 if (!range[i].end)
42 continue;
43
44 common_start = max(range[i].start, start);
45 common_end = min(range[i].end, end);
46 if (common_start > common_end)
47 continue;
48
49 /* new start/end, will add it back at last */
50 start = min(range[i].start, start);
51 end = max(range[i].end, end);
52
53 memmove(&range[i], &range[i + 1],
54 (nr_range - (i + 1)) * sizeof(range[i]));
55 range[nr_range - 1].start = 0;
56 range[nr_range - 1].end = 0;
57 nr_range--;
58 i--;
59 }
60
61 /* Need to add it: */
62 return add_range(range, az, nr_range, start, end);
63 }
64
65 void subtract_range(struct range *range, int az, u64 start, u64 end)
66 {
67 int i, j;
68
69 if (start >= end)
70 return;
71
72 for (j = 0; j < az; j++) {
73 if (!range[j].end)
74 continue;
75
76 if (start <= range[j].start && end >= range[j].end) {
77 range[j].start = 0;
78 range[j].end = 0;
79 continue;
80 }
81
82 if (start <= range[j].start && end < range[j].end &&
83 range[j].start < end) {
84 range[j].start = end;
85 continue;
86 }
87
88
89 if (start > range[j].start && end >= range[j].end &&
90 range[j].end > start) {
91 range[j].end = start;
92 continue;
93 }
94
95 if (start > range[j].start && end < range[j].end) {
96 /* Find the new spare: */
97 for (i = 0; i < az; i++) {
98 if (range[i].end == 0)
99 break;
100 }
101 if (i < az) {
102 range[i].end = range[j].end;
103 range[i].start = end;
104 } else {
105 pr_err("%s: run out of slot in ranges\n",
106 __func__);
107 }
108 range[j].end = start;
109 continue;
110 }
111 }
112 }
113
114 static int cmp_range(const void *x1, const void *x2)
115 {
116 const struct range *r1 = x1;
117 const struct range *r2 = x2;
118
119 if (r1->start < r2->start)
120 return -1;
121 if (r1->start > r2->start)
122 return 1;
123 return 0;
124 }
125
126 int clean_sort_range(struct range *range, int az)
127 {
128 int i, j, k = az - 1, nr_range = az;
129
130 for (i = 0; i < k; i++) {
131 if (range[i].end)
132 continue;
133 for (j = k; j > i; j--) {
134 if (range[j].end) {
135 k = j;
136 break;
137 }
138 }
139 if (j == i)
140 break;
141 range[i].start = range[k].start;
142 range[i].end = range[k].end;
143 range[k].start = 0;
144 range[k].end = 0;
145 k--;
146 }
147 /* count it */
148 for (i = 0; i < az; i++) {
149 if (!range[i].end) {
150 nr_range = i;
151 break;
152 }
153 }
154
155 /* sort them */
156 sort(range, nr_range, sizeof(struct range), cmp_range, NULL);
157
158 return nr_range;
159 }
160
161 void sort_range(struct range *range, int nr_range)
162 {
163 /* sort them */
164 sort(range, nr_range, sizeof(struct range), cmp_range, NULL);
165 }
166
Linux® is a registered trademark of Linus Torvalds in the United States and other countries.
TOMOYO® is a registered trademark of NTT DATA CORPORATION.