dm_table.c revision 1.6 1 1.6 mlelstv /* $NetBSD: dm_table.c,v 1.6 2010/12/23 14:58:13 mlelstv Exp $ */
2 1.2 haad
3 1.2 haad /*
4 1.2 haad * Copyright (c) 2008 The NetBSD Foundation, Inc.
5 1.2 haad * All rights reserved.
6 1.2 haad *
7 1.2 haad * This code is derived from software contributed to The NetBSD Foundation
8 1.2 haad * by Adam Hamsik.
9 1.2 haad *
10 1.2 haad * Redistribution and use in source and binary forms, with or without
11 1.2 haad * modification, are permitted provided that the following conditions
12 1.2 haad * are met:
13 1.2 haad * 1. Redistributions of source code must retain the above copyright
14 1.2 haad * notice, this list of conditions and the following disclaimer.
15 1.2 haad * 2. Redistributions in binary form must reproduce the above copyright
16 1.2 haad * notice, this list of conditions and the following disclaimer in the
17 1.2 haad * documentation and/or other materials provided with the distribution.
18 1.2 haad *
19 1.2 haad * THIS SOFTWARE IS PROVIDED BY THE NETBSD FOUNDATION, INC. AND CONTRIBUTORS
20 1.2 haad * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED
21 1.2 haad * TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
22 1.2 haad * PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE FOUNDATION OR CONTRIBUTORS
23 1.2 haad * BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
24 1.2 haad * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
25 1.2 haad * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
26 1.2 haad * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
27 1.2 haad * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
28 1.2 haad * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
29 1.2 haad * POSSIBILITY OF SUCH DAMAGE.
30 1.2 haad */
31 1.2 haad
32 1.2 haad #include <sys/types.h>
33 1.2 haad #include <sys/param.h>
34 1.2 haad
35 1.2 haad #include <sys/kmem.h>
36 1.2 haad
37 1.2 haad #include "dm.h"
38 1.2 haad
39 1.2 haad /*
40 1.2 haad * There are two types of users of this interface:
41 1.5 haad *
42 1.2 haad * a) Readers such as
43 1.2 haad * dmstrategy, dmgetdisklabel, dmsize, dm_dev_status_ioctl,
44 1.2 haad * dm_table_deps_ioctl, dm_table_status_ioctl, dm_table_reload_ioctl
45 1.2 haad *
46 1.2 haad * b) Writers such as
47 1.2 haad * dm_dev_remove_ioctl, dm_dev_resume_ioctl, dm_table_clear_ioctl
48 1.2 haad *
49 1.2 haad * Writers can work with table_head only when there are no readers. I
50 1.2 haad * use reference counting on io_cnt.
51 1.2 haad *
52 1.2 haad */
53 1.2 haad
54 1.5 haad static int dm_table_busy(dm_table_head_t *, uint8_t);
55 1.2 haad static void dm_table_unbusy(dm_table_head_t *);
56 1.2 haad
57 1.2 haad /*
58 1.2 haad * Function to increment table user reference counter. Return id
59 1.2 haad * of table_id table.
60 1.2 haad * DM_TABLE_ACTIVE will return active table id.
61 1.2 haad * DM_TABLE_INACTIVE will return inactive table id.
62 1.2 haad */
63 1.2 haad static int
64 1.5 haad dm_table_busy(dm_table_head_t * head, uint8_t table_id)
65 1.2 haad {
66 1.2 haad uint8_t id;
67 1.2 haad
68 1.2 haad id = 0;
69 1.2 haad
70 1.2 haad mutex_enter(&head->table_mtx);
71 1.2 haad
72 1.2 haad if (table_id == DM_TABLE_ACTIVE)
73 1.2 haad id = head->cur_active_table;
74 1.2 haad else
75 1.2 haad id = 1 - head->cur_active_table;
76 1.2 haad
77 1.2 haad head->io_cnt++;
78 1.2 haad
79 1.2 haad mutex_exit(&head->table_mtx);
80 1.2 haad return id;
81 1.2 haad }
82 1.2 haad /*
83 1.2 haad * Function release table lock and eventually wakeup all waiters.
84 1.2 haad */
85 1.2 haad static void
86 1.5 haad dm_table_unbusy(dm_table_head_t * head)
87 1.2 haad {
88 1.2 haad KASSERT(head->io_cnt != 0);
89 1.2 haad
90 1.2 haad mutex_enter(&head->table_mtx);
91 1.5 haad
92 1.2 haad if (--head->io_cnt == 0)
93 1.2 haad cv_broadcast(&head->table_cv);
94 1.5 haad
95 1.2 haad mutex_exit(&head->table_mtx);
96 1.2 haad }
97 1.2 haad /*
98 1.2 haad * Return current active table to caller, increment io_cnt reference counter.
99 1.2 haad */
100 1.2 haad dm_table_t *
101 1.5 haad dm_table_get_entry(dm_table_head_t * head, uint8_t table_id)
102 1.2 haad {
103 1.2 haad uint8_t id;
104 1.2 haad
105 1.2 haad id = dm_table_busy(head, table_id);
106 1.5 haad
107 1.2 haad return &head->tables[id];
108 1.2 haad }
109 1.2 haad /*
110 1.2 haad * Decrement io reference counter and wake up all callers, with table_head cv.
111 1.2 haad */
112 1.2 haad void
113 1.5 haad dm_table_release(dm_table_head_t * head, uint8_t table_id)
114 1.2 haad {
115 1.2 haad dm_table_unbusy(head);
116 1.2 haad }
117 1.2 haad /*
118 1.2 haad * Switch table from inactive to active mode. Have to wait until io_cnt is 0.
119 1.2 haad */
120 1.2 haad void
121 1.5 haad dm_table_switch_tables(dm_table_head_t * head)
122 1.2 haad {
123 1.2 haad mutex_enter(&head->table_mtx);
124 1.2 haad
125 1.2 haad while (head->io_cnt != 0)
126 1.2 haad cv_wait(&head->table_cv, &head->table_mtx);
127 1.2 haad
128 1.2 haad head->cur_active_table = 1 - head->cur_active_table;
129 1.2 haad
130 1.2 haad mutex_exit(&head->table_mtx);
131 1.2 haad }
132 1.2 haad /*
133 1.2 haad * Destroy all table data. This function can run when there are no
134 1.2 haad * readers on table lists.
135 1.2 haad *
136 1.2 haad * XXX Is it ok to call kmem_free and potentialy VOP_CLOSE with held mutex ?xs
137 1.2 haad */
138 1.2 haad int
139 1.5 haad dm_table_destroy(dm_table_head_t * head, uint8_t table_id)
140 1.2 haad {
141 1.5 haad dm_table_t *tbl;
142 1.2 haad dm_table_entry_t *table_en;
143 1.2 haad uint8_t id;
144 1.2 haad
145 1.2 haad mutex_enter(&head->table_mtx);
146 1.2 haad
147 1.4 joerg aprint_debug("dm_Table_destroy called with %d--%d\n", table_id, head->io_cnt);
148 1.4 joerg
149 1.2 haad while (head->io_cnt != 0)
150 1.2 haad cv_wait(&head->table_cv, &head->table_mtx);
151 1.2 haad
152 1.2 haad if (table_id == DM_TABLE_ACTIVE)
153 1.2 haad id = head->cur_active_table;
154 1.2 haad else
155 1.2 haad id = 1 - head->cur_active_table;
156 1.5 haad
157 1.2 haad tbl = &head->tables[id];
158 1.5 haad
159 1.5 haad while (!SLIST_EMPTY(tbl)) { /* List Deletion. */
160 1.2 haad table_en = SLIST_FIRST(tbl);
161 1.2 haad /*
162 1.2 haad * Remove target specific config data. After successfull
163 1.2 haad * call table_en->target_config must be set to NULL.
164 1.2 haad */
165 1.5 haad table_en->target->destroy(table_en);
166 1.5 haad
167 1.2 haad SLIST_REMOVE_HEAD(tbl, next);
168 1.2 haad
169 1.2 haad kmem_free(table_en, sizeof(*table_en));
170 1.2 haad }
171 1.2 haad
172 1.2 haad mutex_exit(&head->table_mtx);
173 1.5 haad
174 1.2 haad return 0;
175 1.2 haad }
176 1.2 haad /*
177 1.2 haad * Return length of active table in device.
178 1.2 haad */
179 1.2 haad uint64_t
180 1.5 haad dm_table_size(dm_table_head_t * head)
181 1.2 haad {
182 1.5 haad dm_table_t *tbl;
183 1.2 haad dm_table_entry_t *table_en;
184 1.2 haad uint64_t length;
185 1.2 haad uint8_t id;
186 1.5 haad
187 1.2 haad length = 0;
188 1.2 haad
189 1.2 haad id = dm_table_busy(head, DM_TABLE_ACTIVE);
190 1.5 haad
191 1.2 haad /* Select active table */
192 1.2 haad tbl = &head->tables[id];
193 1.5 haad
194 1.2 haad /*
195 1.2 haad * Find out what tables I want to select.
196 1.2 haad * if length => rawblkno then we should used that table.
197 1.2 haad */
198 1.2 haad SLIST_FOREACH(table_en, tbl, next)
199 1.2 haad length += table_en->length;
200 1.2 haad
201 1.2 haad dm_table_unbusy(head);
202 1.5 haad
203 1.3 jakllsch return length;
204 1.2 haad }
205 1.2 haad /*
206 1.6 mlelstv * Return combined disk geometry
207 1.6 mlelstv */
208 1.6 mlelstv void
209 1.6 mlelstv dm_table_disksize(dm_table_head_t * head, uint64_t *numsecp, unsigned *secsizep)
210 1.6 mlelstv {
211 1.6 mlelstv dm_table_t *tbl;
212 1.6 mlelstv dm_table_entry_t *table_en;
213 1.6 mlelstv uint64_t length;
214 1.6 mlelstv unsigned secsize, tsecsize;
215 1.6 mlelstv uint8_t id;
216 1.6 mlelstv
217 1.6 mlelstv length = 0;
218 1.6 mlelstv
219 1.6 mlelstv id = dm_table_busy(head, DM_TABLE_ACTIVE);
220 1.6 mlelstv
221 1.6 mlelstv /* Select active table */
222 1.6 mlelstv tbl = &head->tables[id];
223 1.6 mlelstv
224 1.6 mlelstv /*
225 1.6 mlelstv * Find out what tables I want to select.
226 1.6 mlelstv * if length => rawblkno then we should used that table.
227 1.6 mlelstv */
228 1.6 mlelstv secsize = 0;
229 1.6 mlelstv SLIST_FOREACH(table_en, tbl, next) {
230 1.6 mlelstv length += table_en->length;
231 1.6 mlelstv (void)table_en->target->secsize(table_en, &tsecsize);
232 1.6 mlelstv if (secsize < tsecsize)
233 1.6 mlelstv secsize = tsecsize;
234 1.6 mlelstv }
235 1.6 mlelstv *numsecp = secsize > 0 ? dbtob(length) / secsize : 0;
236 1.6 mlelstv *secsizep = secsize;
237 1.6 mlelstv
238 1.6 mlelstv dm_table_unbusy(head);
239 1.6 mlelstv }
240 1.6 mlelstv /*
241 1.2 haad * Return > 0 if table is at least one table entry (returns number of entries)
242 1.2 haad * and return 0 if there is not. Target count returned from this function
243 1.2 haad * doesn't need to be true when userspace user receive it (after return
244 1.2 haad * there can be dm_dev_resume_ioctl), therfore this isonly informative.
245 1.2 haad */
246 1.2 haad int
247 1.5 haad dm_table_get_target_count(dm_table_head_t * head, uint8_t table_id)
248 1.5 haad {
249 1.2 haad dm_table_entry_t *table_en;
250 1.2 haad dm_table_t *tbl;
251 1.2 haad uint32_t target_count;
252 1.2 haad uint8_t id;
253 1.2 haad
254 1.2 haad target_count = 0;
255 1.2 haad
256 1.2 haad id = dm_table_busy(head, table_id);
257 1.2 haad
258 1.2 haad tbl = &head->tables[id];
259 1.2 haad
260 1.2 haad SLIST_FOREACH(table_en, tbl, next)
261 1.2 haad target_count++;
262 1.2 haad
263 1.2 haad dm_table_unbusy(head);
264 1.5 haad
265 1.2 haad return target_count;
266 1.2 haad }
267 1.2 haad
268 1.2 haad
269 1.2 haad /*
270 1.2 haad * Initialize table_head structures, I'm trying to keep this structure as
271 1.2 haad * opaque as possible.
272 1.2 haad */
273 1.2 haad void
274 1.5 haad dm_table_head_init(dm_table_head_t * head)
275 1.2 haad {
276 1.2 haad head->cur_active_table = 0;
277 1.2 haad head->io_cnt = 0;
278 1.5 haad
279 1.2 haad /* Initialize tables. */
280 1.2 haad SLIST_INIT(&head->tables[0]);
281 1.2 haad SLIST_INIT(&head->tables[1]);
282 1.2 haad
283 1.2 haad mutex_init(&head->table_mtx, MUTEX_DEFAULT, IPL_NONE);
284 1.2 haad cv_init(&head->table_cv, "dm_io");
285 1.2 haad }
286 1.2 haad /*
287 1.2 haad * Destroy all variables in table_head
288 1.2 haad */
289 1.2 haad void
290 1.5 haad dm_table_head_destroy(dm_table_head_t * head)
291 1.2 haad {
292 1.2 haad KASSERT(!mutex_owned(&head->table_mtx));
293 1.2 haad KASSERT(!cv_has_waiters(&head->table_cv));
294 1.5 haad /* tables doens't exists when I call this routine, therefore it
295 1.5 haad * doesn't make sense to have io_cnt != 0 */
296 1.5 haad KASSERT(head->io_cnt == 0);
297 1.5 haad
298 1.2 haad cv_destroy(&head->table_cv);
299 1.2 haad mutex_destroy(&head->table_mtx);
300 1.2 haad }
301