1 /* $NetBSD: dm_table.c,v 1.21 2021/08/21 22:23:33 andvar Exp $ */
2
3 /*
4 * Copyright (c) 2008 The NetBSD Foundation, Inc.
5 * All rights reserved.
6 *
7 * This code is derived from software contributed to The NetBSD Foundation
8 * by Adam Hamsik.
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 NETBSD FOUNDATION, INC. AND CONTRIBUTORS
20 * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED
21 * TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
22 * PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE FOUNDATION OR CONTRIBUTORS
23 * BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
24 * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
25 * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
26 * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
27 * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
28 * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
29 * POSSIBILITY OF SUCH DAMAGE.
30 */
31 #include <sys/cdefs.h>
32 __KERNEL_RCSID(0, "$NetBSD: dm_table.c,v 1.21 2021/08/21 22:23:33 andvar Exp $");
33
34 #include <sys/types.h>
35 #include <sys/param.h>
36 #include <sys/kmem.h>
37
38 #include "dm.h"
39
40 /*
41 * There are two types of users of this interface:
42 *
43 * a) Readers such as
44 * dmstrategy, dmgetdisklabel, dmsize, dm_dev_status_ioctl,
45 * dm_table_deps_ioctl, dm_table_status_ioctl, dm_table_reload_ioctl
46 *
47 * b) Writers such as
48 * dm_dev_remove_ioctl, dm_dev_resume_ioctl, dm_table_clear_ioctl
49 *
50 * Writers can work with table_head only when there are no readers. I
51 * use reference counting on io_cnt.
52 *
53 */
54
55 static int dm_table_busy(dm_table_head_t *, uint8_t);
56 static void dm_table_unbusy(dm_table_head_t *);
57 static void dm_table_free_deps(dm_table_entry_t *);
58
59
60 /*
61 * Function to increment table user reference counter. Return id
62 * of table_id table.
63 * DM_TABLE_ACTIVE will return active table id.
64 * DM_TABLE_INACTIVE will return inactive table id.
65 */
66 static int
dm_table_busy(dm_table_head_t * head,uint8_t table_id)67 dm_table_busy(dm_table_head_t *head, uint8_t table_id)
68 {
69 uint8_t id;
70
71 mutex_enter(&head->table_mtx);
72
73 if (table_id == DM_TABLE_ACTIVE)
74 id = head->cur_active_table;
75 else
76 id = 1 - head->cur_active_table;
77
78 head->io_cnt++;
79
80 mutex_exit(&head->table_mtx);
81 return id;
82 }
83
84 /*
85 * Function release table lock and eventually wakeup all waiters.
86 */
87 static void
dm_table_unbusy(dm_table_head_t * head)88 dm_table_unbusy(dm_table_head_t *head)
89 {
90
91 KASSERT(head->io_cnt != 0);
92
93 mutex_enter(&head->table_mtx);
94
95 if (--head->io_cnt == 0)
96 cv_broadcast(&head->table_cv);
97
98 mutex_exit(&head->table_mtx);
99 }
100
101 /*
102 * Return current active table to caller, increment io_cnt reference counter.
103 */
104 dm_table_t *
dm_table_get_entry(dm_table_head_t * head,uint8_t table_id)105 dm_table_get_entry(dm_table_head_t *head, uint8_t table_id)
106 {
107 uint8_t id;
108
109 id = dm_table_busy(head, table_id);
110
111 return &head->tables[id];
112 }
113 /*
114 * Decrement io reference counter and wake up all callers, with table_head cv.
115 */
116 void
dm_table_release(dm_table_head_t * head,uint8_t table_id)117 dm_table_release(dm_table_head_t *head, uint8_t table_id)
118 {
119
120 dm_table_unbusy(head);
121 }
122
123 /*
124 * Switch table from inactive to active mode. Have to wait until io_cnt is 0.
125 */
126 void
dm_table_switch_tables(dm_table_head_t * head)127 dm_table_switch_tables(dm_table_head_t *head)
128 {
129
130 mutex_enter(&head->table_mtx);
131
132 while (head->io_cnt != 0)
133 cv_wait(&head->table_cv, &head->table_mtx);
134
135 head->cur_active_table = 1 - head->cur_active_table;
136
137 mutex_exit(&head->table_mtx);
138 }
139
140 /*
141 * Destroy all table data. This function can run when there are no
142 * readers on table lists.
143 *
144 * XXX Is it ok to call kmem_free and potentially VOP_CLOSE with held mutex ?xs
145 */
146 int
dm_table_destroy(dm_table_head_t * head,uint8_t table_id)147 dm_table_destroy(dm_table_head_t *head, uint8_t table_id)
148 {
149 dm_table_t *tbl;
150 dm_table_entry_t *table_en;
151 uint8_t id;
152
153 mutex_enter(&head->table_mtx);
154
155 aprint_debug("dm_Table_destroy called with %d--%d\n", table_id, head->io_cnt);
156
157 while (head->io_cnt != 0)
158 cv_wait(&head->table_cv, &head->table_mtx);
159
160 if (table_id == DM_TABLE_ACTIVE)
161 id = head->cur_active_table;
162 else
163 id = 1 - head->cur_active_table;
164
165 tbl = &head->tables[id];
166
167 while ((table_en = SLIST_FIRST(tbl)) != NULL) {
168 SLIST_REMOVE(tbl, table_en, dm_table_entry, next);
169 if (table_en->target->destroy(table_en) == 0)
170 table_en->target_config = NULL;
171 dm_table_free_deps(table_en);
172 kmem_free(table_en, sizeof(*table_en));
173 }
174 KASSERT(SLIST_EMPTY(tbl));
175
176 mutex_exit(&head->table_mtx);
177
178 return 0;
179 }
180
181 /*
182 * Return length of active table in device.
183 */
184 static uint64_t
dm_table_size_impl(dm_table_head_t * head,int table)185 dm_table_size_impl(dm_table_head_t *head, int table)
186 {
187 dm_table_t *tbl;
188 dm_table_entry_t *table_en;
189 uint64_t length;
190 uint8_t id;
191
192 length = 0;
193
194 id = dm_table_busy(head, table);
195
196 /* Select active table */
197 tbl = &head->tables[id];
198
199 /*
200 * Find out what tables I want to select.
201 * if length => rawblkno then we should used that table.
202 */
203 SLIST_FOREACH(table_en, tbl, next)
204 length += table_en->length;
205
206 dm_table_unbusy(head);
207
208 return length;
209 }
210
211 /*
212 * Return length of active table in device.
213 */
214 uint64_t
dm_table_size(dm_table_head_t * head)215 dm_table_size(dm_table_head_t *head)
216 {
217
218 return dm_table_size_impl(head, DM_TABLE_ACTIVE);
219 }
220
221 /*
222 * Return length of active table in device.
223 */
224 uint64_t
dm_inactive_table_size(dm_table_head_t * head)225 dm_inactive_table_size(dm_table_head_t *head)
226 {
227
228 return dm_table_size_impl(head, DM_TABLE_INACTIVE);
229 }
230
231 /*
232 * Return combined disk geometry
233 */
234 void
dm_table_disksize(dm_table_head_t * head,uint64_t * numsecp,unsigned int * secsizep)235 dm_table_disksize(dm_table_head_t *head, uint64_t *numsecp,
236 unsigned int *secsizep)
237 {
238 dm_table_t *tbl;
239 dm_table_entry_t *table_en;
240 uint64_t length;
241 unsigned int secsize, tsecsize;
242 uint8_t id;
243
244 length = 0;
245
246 id = dm_table_busy(head, DM_TABLE_ACTIVE);
247
248 /* Select active table */
249 tbl = &head->tables[id];
250
251 /*
252 * Find out what tables I want to select.
253 * if length => rawblkno then we should used that table.
254 */
255 secsize = 0;
256 SLIST_FOREACH(table_en, tbl, next) {
257 length += table_en->length;
258 if (table_en->target->secsize)
259 table_en->target->secsize(table_en, &tsecsize);
260 else
261 tsecsize = 0;
262 if (secsize < tsecsize)
263 secsize = tsecsize;
264 }
265
266 if (numsecp)
267 *numsecp = secsize > 0 ? dbtob(length) / secsize : 0;
268 if (secsizep)
269 *secsizep = secsize;
270
271 dm_table_unbusy(head);
272 }
273
274 /*
275 * Return > 0 if table is at least one table entry (returns number of entries)
276 * and return 0 if there is not. Target count returned from this function
277 * doesn't need to be true when userspace user receives it (after return
278 * there can be dm_dev_resume_ioctl), therefore this is only informative.
279 */
280 int
dm_table_get_target_count(dm_table_head_t * head,uint8_t table_id)281 dm_table_get_target_count(dm_table_head_t *head, uint8_t table_id)
282 {
283 dm_table_entry_t *table_en;
284 dm_table_t *tbl;
285 uint32_t target_count;
286 uint8_t id;
287
288 target_count = 0;
289
290 id = dm_table_busy(head, table_id);
291 tbl = &head->tables[id];
292
293 SLIST_FOREACH(table_en, tbl, next)
294 target_count++;
295
296 dm_table_unbusy(head);
297
298 return target_count;
299 }
300
301 /*
302 * Initialize table_head structures, I'm trying to keep this structure as
303 * opaque as possible.
304 */
305 void
dm_table_head_init(dm_table_head_t * head)306 dm_table_head_init(dm_table_head_t *head)
307 {
308
309 head->cur_active_table = 0;
310 head->io_cnt = 0;
311
312 /* Initialize tables. */
313 SLIST_INIT(&head->tables[0]);
314 SLIST_INIT(&head->tables[1]);
315
316 mutex_init(&head->table_mtx, MUTEX_DEFAULT, IPL_NONE);
317 cv_init(&head->table_cv, "dm_io");
318 }
319
320 /*
321 * Destroy all variables in table_head
322 */
323 void
dm_table_head_destroy(dm_table_head_t * head)324 dm_table_head_destroy(dm_table_head_t *head)
325 {
326
327 KASSERT(!mutex_owned(&head->table_mtx));
328 KASSERT(!cv_has_waiters(&head->table_cv));
329 /* tables don't exist when I call this routine, therefore it
330 * doesn't make sense to have io_cnt != 0 */
331 KASSERT(head->io_cnt == 0);
332
333 cv_destroy(&head->table_cv);
334 mutex_destroy(&head->table_mtx);
335 }
336
337 int
dm_table_add_deps(dm_table_entry_t * table_en,dm_pdev_t * pdev)338 dm_table_add_deps(dm_table_entry_t *table_en, dm_pdev_t *pdev)
339 {
340 dm_table_head_t *head;
341 dm_mapping_t *map;
342
343 if (!pdev)
344 return -1;
345
346 head = &table_en->dm_dev->table_head;
347 mutex_enter(&head->table_mtx);
348
349 TAILQ_FOREACH(map, &table_en->pdev_maps, next) {
350 if (map->data.pdev->pdev_vnode->v_rdev ==
351 pdev->pdev_vnode->v_rdev) {
352 mutex_exit(&head->table_mtx);
353 return -1;
354 }
355 }
356
357 map = kmem_alloc(sizeof(*map), KM_SLEEP);
358 map->data.pdev = pdev;
359 aprint_debug("%s: %s\n", __func__, pdev->name);
360 TAILQ_INSERT_TAIL(&table_en->pdev_maps, map, next);
361
362 mutex_exit(&head->table_mtx);
363
364 return 0;
365 }
366
367 /* caller must hold ->table_mtx */
368 static void
dm_table_free_deps(dm_table_entry_t * table_en)369 dm_table_free_deps(dm_table_entry_t *table_en)
370 {
371 dm_mapping_t *map;
372
373 while ((map = TAILQ_FIRST(&table_en->pdev_maps)) != NULL) {
374 TAILQ_REMOVE(&table_en->pdev_maps, map, next);
375 aprint_debug("%s: %s\n", __func__, map->data.pdev->name);
376 kmem_free(map, sizeof(*map));
377 }
378 KASSERT(TAILQ_EMPTY(&table_en->pdev_maps));
379 }
380