xref: /freebsd/sys/kern/subr_rangeset.c (revision c6989859ae9388eeb46a24fe88f9b8d07101c710)
1 /*-
2  * SPDX-License-Identifier: BSD-2-Clause-FreeBSD
3  *
4  * Copyright (c) 2019 The FreeBSD Foundation
5  * All rights reserved.
6  *
7  * This software was developed by Konstantin Belousov <kib@FreeBSD.org>
8  * under sponsorship from the FreeBSD Foundation.
9  *
10  * Redistribution and use in source and binary forms, with or without
11  * modification, are permitted provided that the following conditions
12  * are met:
13  * 1. Redistributions of source code must retain the above copyright
14  *    notice, this list of conditions and the following disclaimer.
15  * 2. Redistributions in binary form must reproduce the above copyright
16  *    notice, this list of conditions and the following disclaimer in the
17  *    documentation and/or other materials provided with the distribution.
18  *
19  * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
20  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
21  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
22  * ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
23  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
24  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
25  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
26  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
27  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
28  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
29  * SUCH DAMAGE.
30  */
31 
32 #include <sys/cdefs.h>
33 __FBSDID("$FreeBSD$");
34 
35 #include <sys/param.h>
36 #include <sys/kernel.h>
37 #include <sys/lock.h>
38 #include <sys/pctrie.h>
39 #include <sys/rangeset.h>
40 #include <vm/uma.h>
41 
42 #ifdef DIAGNOSTIC
43 static void rangeset_check(struct rangeset *rs);
44 #else
45 #define	rangeset_check(rs)
46 #endif
47 
48 static uma_zone_t rs_node_zone;
49 
50 static void
51 rs_rangeset_init(void *arg __unused)
52 {
53 
54 	rs_node_zone = uma_zcreate("rangeset pctrie nodes",
55 	    pctrie_node_size(), NULL, NULL, pctrie_zone_init, NULL,
56 	    UMA_ALIGN_PTR, 0);
57 }
58 SYSINIT(rs, SI_SUB_LOCK, SI_ORDER_ANY, rs_rangeset_init, NULL);
59 
60 static void *
61 rs_node_alloc(struct pctrie *ptree)
62 {
63 	struct rangeset *rs;
64 
65 	rs = __containerof(ptree, struct rangeset, rs_trie);
66 	return (uma_zalloc(rs_node_zone, rs->rs_alloc_flags));
67 }
68 
69 static void
70 rs_node_free(struct pctrie *ptree __unused, void *node)
71 {
72 
73 	uma_zfree(rs_node_zone, node);
74 }
75 
76 void
77 rangeset_init(struct rangeset *rs, rs_dup_data_t dup_data,
78     rs_free_data_t free_data, void *data_ctx, u_int alloc_flags)
79 {
80 
81 	pctrie_init(&rs->rs_trie);
82 	rs->rs_dup_data = dup_data;
83 	rs->rs_free_data = free_data;
84 	rs->rs_data_ctx = data_ctx;
85 	rs->rs_alloc_flags = alloc_flags;
86 }
87 
88 void
89 rangeset_fini(struct rangeset *rs)
90 {
91 
92 	rangeset_check(rs);
93 	rangeset_remove_all(rs);
94 }
95 
96 bool
97 rangeset_check_empty(struct rangeset *rs, uint64_t start, uint64_t end)
98 {
99 	struct rs_el *r;
100 	uint64_t *r1;
101 
102 	rangeset_check(rs);
103 	r1 = pctrie_lookup_le(&rs->rs_trie, end);
104 	if (r1 != NULL) {
105 		r = __containerof(r1, struct rs_el, re_start);
106 		if (r->re_end > start)
107 			return (false);
108 	}
109 	return (true);
110 }
111 
112 int
113 rangeset_insert(struct rangeset *rs, uint64_t start, uint64_t end,
114     void *data)
115 {
116 	struct rs_el *r;
117 	int error;
118 
119 	rangeset_check(rs);
120 	error = rangeset_remove(rs, start, end);
121 	if (error != 0)
122 		return (error);
123 	r = data;
124 	r->re_start = start;
125 	r->re_end = end;
126 	error = pctrie_insert(&rs->rs_trie, &r->re_start, rs_node_alloc);
127 	rangeset_check(rs);
128 	return (error);
129 }
130 
131 int
132 rangeset_remove_pred(struct rangeset *rs, uint64_t start, uint64_t end,
133     rs_pred_t pred)
134 {
135 	struct rs_el *r, *rn;
136 	uint64_t *r1;
137 	int error;
138 
139 	rangeset_check(rs);
140 	error = 0;
141 	for (; end > 0 && start < end;) {
142 		r1 = pctrie_lookup_le(&rs->rs_trie, end - 1);
143 		if (r1 == NULL)
144 			break;
145 		r = __containerof(r1, struct rs_el, re_start);
146 
147 		/*
148 		 * ------============================--|-------|----
149 		 *	 rs    	       	       	   re  s       e
150 		 */
151 		if (r->re_end <= start)
152 			break;
153 
154 		if (r->re_end <= end) {
155 			if (r->re_start < start) {
156 				/*
157 				 * ------========|==============-------|----
158 				 *	 rs    	 s     	      re       e
159 				 */
160 				if (pred(rs->rs_data_ctx, r))
161 					r->re_end = start;
162 				break;
163 			}
164 
165 			/*
166 			 * ------|--------===================----------|----
167 			 *	 s    	  rs   	       	   re          e
168 			 */
169 			end = r->re_start;
170 			if (pred(rs->rs_data_ctx, r)) {
171 				pctrie_remove(&rs->rs_trie, r->re_start,
172 				    rs_node_free);
173 				rs->rs_free_data(rs->rs_data_ctx, r);
174 			}
175 			continue;
176 		}
177 
178 		/*
179 		 * ------|--------====================|==========----
180 		 *	 s    	  rs   	       	      e         re
181 		 */
182 		if (r->re_start >= start) {
183 			if (pred(rs->rs_data_ctx, r)) {
184 				pctrie_remove(&rs->rs_trie, r->re_start,
185 				    rs_node_free);
186 				r->re_start = end;
187 				error = pctrie_insert(&rs->rs_trie,
188 				    &r->re_start, rs_node_alloc);
189 				/*
190 				 * The insert above must succeed
191 				 * because rs_node zone is marked
192 				 * nofree and we freed one element
193 				 * just before.
194 				 */
195 				MPASS(error == 0);
196 			} else {
197 				end = r->re_start;
198 			}
199 			continue;
200 		}
201 
202 		/*
203 		 * ------=========|===================|==========----
204 		 *	 rs   	  s    	       	      e         re
205 		 */
206 		if (pred(rs->rs_data_ctx, r)) {
207 			/*
208 			 * Split.  Can only happen once, and then if
209 			 * any allocation fails, the rangeset is kept
210 			 * intact.
211 			 */
212 			rn = rs->rs_dup_data(rs->rs_data_ctx, r);
213 			if (rn == NULL) {
214 				error = ENOMEM;
215 				break;
216 			}
217 			rn->re_start = end;
218 			rn->re_end = r->re_end;
219 			error = pctrie_insert(&rs->rs_trie, &rn->re_start,
220 			    rs_node_alloc);
221 			if (error != 0) {
222 				rs->rs_free_data(rs->rs_data_ctx, rn);
223 				break;
224 			}
225 			r->re_end = start;
226 		}
227 		break;
228 	}
229 	rangeset_check(rs);
230 	return (error);
231 }
232 
233 static bool
234 rangeset_true_pred(void *ctx __unused, void *r __unused)
235 {
236 
237 	return (true);
238 }
239 
240 int
241 rangeset_remove(struct rangeset *rs, uint64_t start, uint64_t end)
242 {
243 
244 	return (rangeset_remove_pred(rs, start, end, rangeset_true_pred));
245 }
246 
247 void
248 rangeset_remove_all(struct rangeset *rs)
249 {
250 	struct rs_el *r;
251 	uint64_t *r1;
252 
253 	for (;;) {
254 		r1 = pctrie_lookup_ge(&rs->rs_trie, 0);
255 		if (r1 == NULL)
256 			break;
257 		r = __containerof(r1, struct rs_el, re_start);
258 		pctrie_remove(&rs->rs_trie, r->re_start, rs_node_free);
259 		rs->rs_free_data(rs->rs_data_ctx, r);
260 	}
261 }
262 
263 void *
264 rangeset_lookup(struct rangeset *rs, uint64_t place)
265 {
266 	struct rs_el *r;
267 	uint64_t *r1;
268 
269 	rangeset_check(rs);
270 	r1 = pctrie_lookup_le(&rs->rs_trie, place);
271 	if (r1 == NULL)
272 		return (NULL);
273 	r = __containerof(r1, struct rs_el, re_start);
274 	if (r->re_end <= place)
275 		return (NULL);
276 	return (r);
277 }
278 
279 int
280 rangeset_copy(struct rangeset *dst_rs, struct rangeset *src_rs)
281 {
282 	struct rs_el *src_r, *dst_r;
283 	uint64_t cursor, *r1;
284 	int error;
285 
286 	MPASS(pctrie_is_empty(&dst_rs->rs_trie));
287 	rangeset_check(src_rs);
288 	MPASS(dst_rs->rs_dup_data == src_rs->rs_dup_data);
289 
290 	error = 0;
291 	for (cursor = 0;; cursor = src_r->re_start + 1) {
292 		r1 = pctrie_lookup_ge(&src_rs->rs_trie, cursor);
293 		if (r1 == NULL)
294 			break;
295 		src_r = __containerof(r1, struct rs_el, re_start);
296 		dst_r = dst_rs->rs_dup_data(dst_rs->rs_data_ctx, src_r);
297 		if (dst_r == NULL) {
298 			error = ENOMEM;
299 			break;
300 		}
301 		error = pctrie_insert(&dst_rs->rs_trie, &dst_r->re_start,
302 		    rs_node_alloc);
303 		if (error != 0)
304 			break;
305 	}
306 	if (error != 0)
307 		rangeset_remove_all(dst_rs);
308 	return (error);
309 }
310 
311 #ifdef DIAGNOSTIC
312 static void
313 rangeset_check(struct rangeset *rs)
314 {
315 	struct rs_el *r, *rp;
316 	uint64_t cursor, *r1;
317 
318 	for (cursor = 0, rp = NULL;; cursor = r->re_start + 1, rp = r) {
319 		r1 = pctrie_lookup_ge(&rs->rs_trie, cursor);
320 		if (r1 == NULL)
321 			break;
322 		r = __containerof(r1, struct rs_el, re_start);
323 		KASSERT(r->re_start < r->re_end,
324 		    ("invalid interval rs %p elem %p (%#jx, %#jx)",
325 		    rs, r, (uintmax_t)r->re_start,  (uintmax_t)r->re_end));
326 		if (rp != NULL) {
327 			KASSERT(rp->re_end <= r->re_start,
328 			    ("non-ascending neighbors rs %p "
329 			    "prev elem %p (%#jx, %#jx) elem %p (%#jx, %#jx)",
330 			    rs, rp,  (uintmax_t)rp->re_start,
331 			    (uintmax_t)rp->re_end, r,  (uintmax_t)r->re_start,
332 			    (uintmax_t)r->re_end));
333 		}
334 	}
335 }
336 #endif
337 
338 #include "opt_ddb.h"
339 #ifdef DDB
340 #include <sys/kernel.h>
341 #include <ddb/ddb.h>
342 
343 DB_SHOW_COMMAND(rangeset, rangeset_show_fn)
344 {
345 	struct rangeset *rs;
346 	struct rs_el *r;
347 	uint64_t cursor, *r1;
348 
349 	if (!have_addr) {
350 		db_printf("show rangeset addr\n");
351 		return;
352 	}
353 
354 	rs = (struct rangeset *)addr;
355 	db_printf("rangeset %p\n", rs);
356 	for (cursor = 0;; cursor = r->re_start + 1) {
357 		r1 = pctrie_lookup_ge(&rs->rs_trie, cursor);
358 		if (r1 == NULL)
359 			break;
360 		r = __containerof(r1, struct rs_el, re_start);
361 		db_printf("  el %p start %#jx end %#jx\n",
362 		    r, r->re_start, r->re_end);
363 	}
364 }
365 #endif
366