xref: /freebsd/sys/kern/subr_rangeset.c (revision 06c3fb2749bda94cb5201f81ffdb8fa6c3161b2e)
1 /*-
2  * SPDX-License-Identifier: BSD-2-Clause
3  *
4  * Copyright (c) 2019 The FreeBSD Foundation
5  *
6  * This software was developed by Konstantin Belousov <kib@FreeBSD.org>
7  * under sponsorship from the FreeBSD Foundation.
8  *
9  * Redistribution and use in source and binary forms, with or without
10  * modification, are permitted provided that the following conditions
11  * are met:
12  * 1. Redistributions of source code must retain the above copyright
13  *    notice, this list of conditions and the following disclaimer.
14  * 2. Redistributions in binary form must reproduce the above copyright
15  *    notice, this list of conditions and the following disclaimer in the
16  *    documentation and/or other materials provided with the distribution.
17  *
18  * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
19  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
20  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
21  * ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
22  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
23  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
24  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
25  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
26  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
27  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
28  * SUCH DAMAGE.
29  */
30 
31 #include <sys/param.h>
32 #include <sys/kernel.h>
33 #include <sys/lock.h>
34 #include <sys/pctrie.h>
35 #include <sys/rangeset.h>
36 #include <vm/uma.h>
37 
38 #ifdef DIAGNOSTIC
39 static void rangeset_check(struct rangeset *rs);
40 #else
41 #define	rangeset_check(rs)
42 #endif
43 
44 static uma_zone_t rs_node_zone;
45 
46 static void
47 rs_rangeset_init(void *arg __unused)
48 {
49 
50 	rs_node_zone = uma_zcreate("rangeset pctrie nodes",
51 	    pctrie_node_size(), NULL, NULL, pctrie_zone_init, NULL,
52 	    UMA_ALIGN_PTR, 0);
53 }
54 SYSINIT(rs, SI_SUB_LOCK, SI_ORDER_ANY, rs_rangeset_init, NULL);
55 
56 static void *
57 rs_node_alloc(struct pctrie *ptree)
58 {
59 	struct rangeset *rs;
60 
61 	rs = __containerof(ptree, struct rangeset, rs_trie);
62 	return (uma_zalloc(rs_node_zone, rs->rs_alloc_flags));
63 }
64 
65 static void
66 rs_node_free(struct pctrie *ptree __unused, void *node)
67 {
68 
69 	uma_zfree(rs_node_zone, node);
70 }
71 
72 PCTRIE_DEFINE(RANGESET, rs_el, re_start, rs_node_alloc, rs_node_free);
73 
74 void
75 rangeset_init(struct rangeset *rs, rs_dup_data_t dup_data,
76     rs_free_data_t free_data, void *data_ctx, u_int alloc_flags)
77 {
78 
79 	pctrie_init(&rs->rs_trie);
80 	rs->rs_dup_data = dup_data;
81 	rs->rs_free_data = free_data;
82 	rs->rs_data_ctx = data_ctx;
83 	rs->rs_alloc_flags = alloc_flags;
84 }
85 
86 void
87 rangeset_fini(struct rangeset *rs)
88 {
89 
90 	rangeset_check(rs);
91 	rangeset_remove_all(rs);
92 }
93 
94 bool
95 rangeset_check_empty(struct rangeset *rs, uint64_t start, uint64_t end)
96 {
97 	struct rs_el *r;
98 
99 	rangeset_check(rs);
100 	r = RANGESET_PCTRIE_LOOKUP_LE(&rs->rs_trie, end);
101 	return (r == NULL || r->re_end <= start);
102 }
103 
104 int
105 rangeset_insert(struct rangeset *rs, uint64_t start, uint64_t end,
106     void *data)
107 {
108 	struct rs_el *r;
109 	int error;
110 
111 	rangeset_check(rs);
112 	error = rangeset_remove(rs, start, end);
113 	if (error != 0)
114 		return (error);
115 	r = data;
116 	r->re_start = start;
117 	r->re_end = end;
118 	error = RANGESET_PCTRIE_INSERT(&rs->rs_trie, r);
119 	rangeset_check(rs);
120 	return (error);
121 }
122 
123 int
124 rangeset_remove_pred(struct rangeset *rs, uint64_t start, uint64_t end,
125     rs_pred_t pred)
126 {
127 	struct rs_el *r, *rn;
128 	int error;
129 
130 	rangeset_check(rs);
131 	error = 0;
132 	for (; end > 0 && start < end;) {
133 		r = RANGESET_PCTRIE_LOOKUP_LE(&rs->rs_trie, end - 1);
134 		if (r == NULL)
135 			break;
136 
137 		/*
138 		 * ------============================--|-------|----
139 		 *	 rs    	       	       	   re  s       e
140 		 */
141 		if (r->re_end <= start)
142 			break;
143 
144 		if (r->re_end <= end) {
145 			if (r->re_start < start) {
146 				/*
147 				 * ------========|==============-------|----
148 				 *	 rs    	 s     	      re       e
149 				 */
150 				if (pred(rs->rs_data_ctx, r))
151 					r->re_end = start;
152 				break;
153 			}
154 
155 			/*
156 			 * ------|--------===================----------|----
157 			 *	 s    	  rs   	       	   re          e
158 			 */
159 			end = r->re_start;
160 			if (pred(rs->rs_data_ctx, r)) {
161 				RANGESET_PCTRIE_REMOVE(&rs->rs_trie,
162 				    r->re_start);
163 				rs->rs_free_data(rs->rs_data_ctx, r);
164 			}
165 			continue;
166 		}
167 
168 		/*
169 		 * ------|--------====================|==========----
170 		 *	 s    	  rs   	       	      e         re
171 		 */
172 		if (r->re_start >= start) {
173 			if (pred(rs->rs_data_ctx, r)) {
174 				RANGESET_PCTRIE_REMOVE(&rs->rs_trie,
175 				    r->re_start);
176 				r->re_start = end;
177 				error = RANGESET_PCTRIE_INSERT(&rs->rs_trie, r);
178 				/*
179 				 * The insert above must succeed
180 				 * because rs_node zone is marked
181 				 * nofree and we freed one element
182 				 * just before.
183 				 */
184 				MPASS(error == 0);
185 			} else {
186 				end = r->re_start;
187 			}
188 			continue;
189 		}
190 
191 		/*
192 		 * ------=========|===================|==========----
193 		 *	 rs   	  s    	       	      e         re
194 		 */
195 		if (pred(rs->rs_data_ctx, r)) {
196 			/*
197 			 * Split.  Can only happen once, and then if
198 			 * any allocation fails, the rangeset is kept
199 			 * intact.
200 			 */
201 			rn = rs->rs_dup_data(rs->rs_data_ctx, r);
202 			if (rn == NULL) {
203 				error = ENOMEM;
204 				break;
205 			}
206 			rn->re_start = end;
207 			rn->re_end = r->re_end;
208 			error = RANGESET_PCTRIE_INSERT(&rs->rs_trie, rn);
209 			if (error != 0) {
210 				rs->rs_free_data(rs->rs_data_ctx, rn);
211 				break;
212 			}
213 			r->re_end = start;
214 		}
215 		break;
216 	}
217 	rangeset_check(rs);
218 	return (error);
219 }
220 
221 static bool
222 rangeset_true_pred(void *ctx __unused, void *r __unused)
223 {
224 
225 	return (true);
226 }
227 
228 int
229 rangeset_remove(struct rangeset *rs, uint64_t start, uint64_t end)
230 {
231 
232 	return (rangeset_remove_pred(rs, start, end, rangeset_true_pred));
233 }
234 
235 void
236 rangeset_remove_all(struct rangeset *rs)
237 {
238 	struct rs_el *r;
239 
240 	for (;;) {
241 		r = RANGESET_PCTRIE_LOOKUP_GE(&rs->rs_trie, 0);
242 		if (r == NULL)
243 			break;
244 		RANGESET_PCTRIE_REMOVE(&rs->rs_trie, r->re_start);
245 		rs->rs_free_data(rs->rs_data_ctx, r);
246 	}
247 }
248 
249 void *
250 rangeset_lookup(struct rangeset *rs, uint64_t place)
251 {
252 	struct rs_el *r;
253 
254 	rangeset_check(rs);
255 	r = RANGESET_PCTRIE_LOOKUP_LE(&rs->rs_trie, place);
256 	if (r == NULL)
257 		return (NULL);
258 	if (r->re_end <= place)
259 		return (NULL);
260 	return (r);
261 }
262 
263 int
264 rangeset_copy(struct rangeset *dst_rs, struct rangeset *src_rs)
265 {
266 	struct rs_el *src_r, *dst_r;
267 	uint64_t cursor;
268 	int error;
269 
270 	MPASS(pctrie_is_empty(&dst_rs->rs_trie));
271 	rangeset_check(src_rs);
272 	MPASS(dst_rs->rs_dup_data == src_rs->rs_dup_data);
273 
274 	error = 0;
275 	for (cursor = 0;; cursor = src_r->re_start + 1) {
276 		src_r = RANGESET_PCTRIE_LOOKUP_GE(&src_rs->rs_trie, cursor);
277 		if (src_r == NULL)
278 			break;
279 		dst_r = dst_rs->rs_dup_data(dst_rs->rs_data_ctx, src_r);
280 		if (dst_r == NULL) {
281 			error = ENOMEM;
282 			break;
283 		}
284 		error = RANGESET_PCTRIE_INSERT(&dst_rs->rs_trie, dst_r);
285 		if (error != 0)
286 			break;
287 	}
288 	if (error != 0)
289 		rangeset_remove_all(dst_rs);
290 	return (error);
291 }
292 
293 #ifdef DIAGNOSTIC
294 static void
295 rangeset_check(struct rangeset *rs)
296 {
297 	struct rs_el *r, *rp;
298 	uint64_t cursor;
299 
300 	for (cursor = 0, rp = NULL;; cursor = r->re_start + 1, rp = r) {
301 		r = RANGESET_PCTRIE_LOOKUP_GE(&rs->rs_trie, cursor);
302 		if (r == NULL)
303 			break;
304 		KASSERT(r->re_start < r->re_end,
305 		    ("invalid interval rs %p elem %p (%#jx, %#jx)",
306 		    rs, r, (uintmax_t)r->re_start,  (uintmax_t)r->re_end));
307 		if (rp != NULL) {
308 			KASSERT(rp->re_end <= r->re_start,
309 			    ("non-ascending neighbors rs %p "
310 			    "prev elem %p (%#jx, %#jx) elem %p (%#jx, %#jx)",
311 			    rs, rp,  (uintmax_t)rp->re_start,
312 			    (uintmax_t)rp->re_end, r,  (uintmax_t)r->re_start,
313 			    (uintmax_t)r->re_end));
314 		}
315 	}
316 }
317 #endif
318 
319 #include "opt_ddb.h"
320 #ifdef DDB
321 #include <sys/kernel.h>
322 #include <ddb/ddb.h>
323 
324 DB_SHOW_COMMAND(rangeset, rangeset_show_fn)
325 {
326 	struct rangeset *rs;
327 	struct rs_el *r;
328 	uint64_t cursor;
329 
330 	if (!have_addr) {
331 		db_printf("show rangeset addr\n");
332 		return;
333 	}
334 
335 	rs = (struct rangeset *)addr;
336 	db_printf("rangeset %p\n", rs);
337 	for (cursor = 0;; cursor = r->re_start + 1) {
338 		r = RANGESET_PCTRIE_LOOKUP_GE(&rs->rs_trie, cursor);
339 		if (r == NULL)
340 			break;
341 		db_printf("  el %p start %#jx end %#jx\n",
342 		    r, r->re_start, r->re_end);
343 	}
344 }
345 #endif
346