xref: /freebsd/sys/kern/subr_rangeset.c (revision 031beb4e239bfce798af17f5fe8dba8bcaf13d99)
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/cdefs.h>
32 #include <sys/param.h>
33 #include <sys/kernel.h>
34 #include <sys/lock.h>
35 #include <sys/pctrie.h>
36 #include <sys/rangeset.h>
37 #include <vm/uma.h>
38 
39 #ifdef DIAGNOSTIC
40 static void rangeset_check(struct rangeset *rs);
41 #else
42 #define	rangeset_check(rs)
43 #endif
44 
45 static uma_zone_t rs_node_zone;
46 
47 static void
48 rs_rangeset_init(void *arg __unused)
49 {
50 
51 	rs_node_zone = uma_zcreate("rangeset pctrie nodes",
52 	    pctrie_node_size(), NULL, NULL, pctrie_zone_init, NULL,
53 	    UMA_ALIGN_PTR, 0);
54 }
55 SYSINIT(rs, SI_SUB_LOCK, SI_ORDER_ANY, rs_rangeset_init, NULL);
56 
57 static void *
58 rs_node_alloc(struct pctrie *ptree)
59 {
60 	struct rangeset *rs;
61 
62 	rs = __containerof(ptree, struct rangeset, rs_trie);
63 	return (uma_zalloc(rs_node_zone, rs->rs_alloc_flags));
64 }
65 
66 static void
67 rs_node_free(struct pctrie *ptree __unused, void *node)
68 {
69 
70 	uma_zfree(rs_node_zone, node);
71 }
72 
73 PCTRIE_DEFINE(RANGESET, rs_el, re_start, rs_node_alloc, rs_node_free);
74 
75 void
76 rangeset_init(struct rangeset *rs, rs_dup_data_t dup_data,
77     rs_free_data_t free_data, void *data_ctx, u_int alloc_flags)
78 {
79 
80 	pctrie_init(&rs->rs_trie);
81 	rs->rs_dup_data = dup_data;
82 	rs->rs_free_data = free_data;
83 	rs->rs_data_ctx = data_ctx;
84 	rs->rs_alloc_flags = alloc_flags;
85 }
86 
87 void
88 rangeset_fini(struct rangeset *rs)
89 {
90 
91 	rangeset_check(rs);
92 	rangeset_remove_all(rs);
93 }
94 
95 bool
96 rangeset_check_empty(struct rangeset *rs, uint64_t start, uint64_t end)
97 {
98 	struct rs_el *r;
99 
100 	rangeset_check(rs);
101 	r = RANGESET_PCTRIE_LOOKUP_LE(&rs->rs_trie, end);
102 	return (r == NULL || r->re_end <= start);
103 }
104 
105 int
106 rangeset_insert(struct rangeset *rs, uint64_t start, uint64_t end,
107     void *data)
108 {
109 	struct rs_el *r;
110 	int error;
111 
112 	rangeset_check(rs);
113 	error = rangeset_remove(rs, start, end);
114 	if (error != 0)
115 		return (error);
116 	r = data;
117 	r->re_start = start;
118 	r->re_end = end;
119 	error = RANGESET_PCTRIE_INSERT(&rs->rs_trie, r);
120 	rangeset_check(rs);
121 	return (error);
122 }
123 
124 int
125 rangeset_remove_pred(struct rangeset *rs, uint64_t start, uint64_t end,
126     rs_pred_t pred)
127 {
128 	struct rs_el *r, *rn;
129 	int error;
130 
131 	rangeset_check(rs);
132 	error = 0;
133 	for (; end > 0 && start < end;) {
134 		r = RANGESET_PCTRIE_LOOKUP_LE(&rs->rs_trie, end - 1);
135 		if (r == NULL)
136 			break;
137 
138 		/*
139 		 * ------============================--|-------|----
140 		 *	 rs    	       	       	   re  s       e
141 		 */
142 		if (r->re_end <= start)
143 			break;
144 
145 		if (r->re_end <= end) {
146 			if (r->re_start < start) {
147 				/*
148 				 * ------========|==============-------|----
149 				 *	 rs    	 s     	      re       e
150 				 */
151 				if (pred(rs->rs_data_ctx, r))
152 					r->re_end = start;
153 				break;
154 			}
155 
156 			/*
157 			 * ------|--------===================----------|----
158 			 *	 s    	  rs   	       	   re          e
159 			 */
160 			end = r->re_start;
161 			if (pred(rs->rs_data_ctx, r)) {
162 				RANGESET_PCTRIE_REMOVE(&rs->rs_trie,
163 				    r->re_start);
164 				rs->rs_free_data(rs->rs_data_ctx, r);
165 			}
166 			continue;
167 		}
168 
169 		/*
170 		 * ------|--------====================|==========----
171 		 *	 s    	  rs   	       	      e         re
172 		 */
173 		if (r->re_start >= start) {
174 			if (pred(rs->rs_data_ctx, r)) {
175 				RANGESET_PCTRIE_REMOVE(&rs->rs_trie,
176 				    r->re_start);
177 				r->re_start = end;
178 				error = RANGESET_PCTRIE_INSERT(&rs->rs_trie, r);
179 				/*
180 				 * The insert above must succeed
181 				 * because rs_node zone is marked
182 				 * nofree and we freed one element
183 				 * just before.
184 				 */
185 				MPASS(error == 0);
186 			} else {
187 				end = r->re_start;
188 			}
189 			continue;
190 		}
191 
192 		/*
193 		 * ------=========|===================|==========----
194 		 *	 rs   	  s    	       	      e         re
195 		 */
196 		if (pred(rs->rs_data_ctx, r)) {
197 			/*
198 			 * Split.  Can only happen once, and then if
199 			 * any allocation fails, the rangeset is kept
200 			 * intact.
201 			 */
202 			rn = rs->rs_dup_data(rs->rs_data_ctx, r);
203 			if (rn == NULL) {
204 				error = ENOMEM;
205 				break;
206 			}
207 			rn->re_start = end;
208 			rn->re_end = r->re_end;
209 			error = RANGESET_PCTRIE_INSERT(&rs->rs_trie, rn);
210 			if (error != 0) {
211 				rs->rs_free_data(rs->rs_data_ctx, rn);
212 				break;
213 			}
214 			r->re_end = start;
215 		}
216 		break;
217 	}
218 	rangeset_check(rs);
219 	return (error);
220 }
221 
222 static bool
223 rangeset_true_pred(void *ctx __unused, void *r __unused)
224 {
225 
226 	return (true);
227 }
228 
229 int
230 rangeset_remove(struct rangeset *rs, uint64_t start, uint64_t end)
231 {
232 
233 	return (rangeset_remove_pred(rs, start, end, rangeset_true_pred));
234 }
235 
236 void
237 rangeset_remove_all(struct rangeset *rs)
238 {
239 	struct rs_el *r;
240 
241 	for (;;) {
242 		r = RANGESET_PCTRIE_LOOKUP_GE(&rs->rs_trie, 0);
243 		if (r == NULL)
244 			break;
245 		RANGESET_PCTRIE_REMOVE(&rs->rs_trie, r->re_start);
246 		rs->rs_free_data(rs->rs_data_ctx, r);
247 	}
248 }
249 
250 void *
251 rangeset_lookup(struct rangeset *rs, uint64_t place)
252 {
253 	struct rs_el *r;
254 
255 	rangeset_check(rs);
256 	r = RANGESET_PCTRIE_LOOKUP_LE(&rs->rs_trie, place);
257 	if (r == NULL)
258 		return (NULL);
259 	if (r->re_end <= place)
260 		return (NULL);
261 	return (r);
262 }
263 
264 int
265 rangeset_copy(struct rangeset *dst_rs, struct rangeset *src_rs)
266 {
267 	struct rs_el *src_r, *dst_r;
268 	uint64_t cursor;
269 	int error;
270 
271 	MPASS(pctrie_is_empty(&dst_rs->rs_trie));
272 	rangeset_check(src_rs);
273 	MPASS(dst_rs->rs_dup_data == src_rs->rs_dup_data);
274 
275 	error = 0;
276 	for (cursor = 0;; cursor = src_r->re_start + 1) {
277 		src_r = RANGESET_PCTRIE_LOOKUP_GE(&src_rs->rs_trie, cursor);
278 		if (src_r == NULL)
279 			break;
280 		dst_r = dst_rs->rs_dup_data(dst_rs->rs_data_ctx, src_r);
281 		if (dst_r == NULL) {
282 			error = ENOMEM;
283 			break;
284 		}
285 		error = RANGESET_PCTRIE_INSERT(&dst_rs->rs_trie, dst_r);
286 		if (error != 0)
287 			break;
288 	}
289 	if (error != 0)
290 		rangeset_remove_all(dst_rs);
291 	return (error);
292 }
293 
294 #ifdef DIAGNOSTIC
295 static void
296 rangeset_check(struct rangeset *rs)
297 {
298 	struct rs_el *r, *rp;
299 	uint64_t cursor;
300 
301 	for (cursor = 0, rp = NULL;; cursor = r->re_start + 1, rp = r) {
302 		r = RANGESET_PCTRIE_LOOKUP_GE(&rs->rs_trie, cursor);
303 		if (r == NULL)
304 			break;
305 		KASSERT(r->re_start < r->re_end,
306 		    ("invalid interval rs %p elem %p (%#jx, %#jx)",
307 		    rs, r, (uintmax_t)r->re_start,  (uintmax_t)r->re_end));
308 		if (rp != NULL) {
309 			KASSERT(rp->re_end <= r->re_start,
310 			    ("non-ascending neighbors rs %p "
311 			    "prev elem %p (%#jx, %#jx) elem %p (%#jx, %#jx)",
312 			    rs, rp,  (uintmax_t)rp->re_start,
313 			    (uintmax_t)rp->re_end, r,  (uintmax_t)r->re_start,
314 			    (uintmax_t)r->re_end));
315 		}
316 	}
317 }
318 #endif
319 
320 #include "opt_ddb.h"
321 #ifdef DDB
322 #include <sys/kernel.h>
323 #include <ddb/ddb.h>
324 
325 DB_SHOW_COMMAND(rangeset, rangeset_show_fn)
326 {
327 	struct rangeset *rs;
328 	struct rs_el *r;
329 	uint64_t cursor;
330 
331 	if (!have_addr) {
332 		db_printf("show rangeset addr\n");
333 		return;
334 	}
335 
336 	rs = (struct rangeset *)addr;
337 	db_printf("rangeset %p\n", rs);
338 	for (cursor = 0;; cursor = r->re_start + 1) {
339 		r = RANGESET_PCTRIE_LOOKUP_GE(&rs->rs_trie, cursor);
340 		if (r == NULL)
341 			break;
342 		db_printf("  el %p start %#jx end %#jx\n",
343 		    r, r->re_start, r->re_end);
344 	}
345 }
346 #endif
347