dm - undo my pointless moving of dm.h
[dragonfly.git] / sys / dev / disk / dm / dm_table.c
CommitLineData
ff56536e
AH
1/* $NetBSD: dm_table.c,v 1.5 2010/01/04 00:19:08 haad 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
32#include <sys/types.h>
33#include <sys/param.h>
34
5b279a20 35#include <sys/malloc.h>
ff56536e 36
a84e173e 37#include <dev/disk/dm/dm.h>
ff56536e
AH
38
39/*
40 * There are two types of users of this interface:
41 *
42 * a) Readers such as
43 * dmstrategy, dmgetdisklabel, dmsize, dm_dev_status_ioctl,
44 * dm_table_deps_ioctl, dm_table_status_ioctl, dm_table_reload_ioctl
45 *
46 * b) Writers such as
47 * dm_dev_remove_ioctl, dm_dev_resume_ioctl, dm_table_clear_ioctl
48 *
8f77157d
AH
49 * Writers can work with table_head only when there are no readers. We
50 * simply use shared/exclusive locking to ensure this.
ff56536e
AH
51 */
52
53static int dm_table_busy(dm_table_head_t *, uint8_t);
54static void dm_table_unbusy(dm_table_head_t *);
55
56/*
57 * Function to increment table user reference counter. Return id
58 * of table_id table.
59 * DM_TABLE_ACTIVE will return active table id.
60 * DM_TABLE_INACTIVE will return inactive table id.
61 */
62static int
63dm_table_busy(dm_table_head_t * head, uint8_t table_id)
64{
65 uint8_t id;
66
67 id = 0;
68
8f77157d 69 lockmgr(&head->table_mtx, LK_SHARED);
ff56536e
AH
70
71 if (table_id == DM_TABLE_ACTIVE)
72 id = head->cur_active_table;
73 else
74 id = 1 - head->cur_active_table;
75
1efa8440 76 atomic_add_int(&head->io_cnt, 1);
ff56536e 77
ff56536e
AH
78 return id;
79}
80/*
81 * Function release table lock and eventually wakeup all waiters.
82 */
83static void
84dm_table_unbusy(dm_table_head_t * head)
85{
5b279a20 86 KKASSERT(head->io_cnt != 0);
ff56536e 87
1efa8440 88 atomic_subtract_int(&head->io_cnt, 1);
ff56536e 89
5b279a20 90 lockmgr(&head->table_mtx, LK_RELEASE);
ff56536e
AH
91}
92/*
93 * Return current active table to caller, increment io_cnt reference counter.
94 */
95dm_table_t *
96dm_table_get_entry(dm_table_head_t * head, uint8_t table_id)
97{
98 uint8_t id;
99
100 id = dm_table_busy(head, table_id);
101
102 return &head->tables[id];
103}
104/*
8f77157d 105 * Decrement io reference counter and release shared lock.
ff56536e
AH
106 */
107void
108dm_table_release(dm_table_head_t * head, uint8_t table_id)
109{
110 dm_table_unbusy(head);
111}
112/*
113 * Switch table from inactive to active mode. Have to wait until io_cnt is 0.
114 */
115void
116dm_table_switch_tables(dm_table_head_t * head)
117{
5b279a20 118 lockmgr(&head->table_mtx, LK_EXCLUSIVE);
ff56536e 119
ff56536e
AH
120 head->cur_active_table = 1 - head->cur_active_table;
121
5b279a20 122 lockmgr(&head->table_mtx, LK_RELEASE);
ff56536e
AH
123}
124/*
125 * Destroy all table data. This function can run when there are no
126 * readers on table lists.
ff56536e
AH
127 */
128int
129dm_table_destroy(dm_table_head_t * head, uint8_t table_id)
130{
131 dm_table_t *tbl;
132 dm_table_entry_t *table_en;
133 uint8_t id;
134
5b279a20 135 lockmgr(&head->table_mtx, LK_EXCLUSIVE);
ff56536e
AH
136
137 aprint_debug("dm_Table_destroy called with %d--%d\n", table_id, head->io_cnt);
138
ff56536e
AH
139 if (table_id == DM_TABLE_ACTIVE)
140 id = head->cur_active_table;
141 else
142 id = 1 - head->cur_active_table;
143
144 tbl = &head->tables[id];
145
146 while (!SLIST_EMPTY(tbl)) { /* List Deletion. */
147 table_en = SLIST_FIRST(tbl);
148 /*
149 * Remove target specific config data. After successfull
150 * call table_en->target_config must be set to NULL.
151 */
152 table_en->target->destroy(table_en);
153
154 SLIST_REMOVE_HEAD(tbl, next);
155
5b279a20 156 kfree(table_en, M_DM);
ff56536e
AH
157 }
158
5b279a20 159 lockmgr(&head->table_mtx, LK_RELEASE);
ff56536e
AH
160
161 return 0;
162}
163/*
164 * Return length of active table in device.
165 */
166uint64_t
167dm_table_size(dm_table_head_t * head)
168{
169 dm_table_t *tbl;
170 dm_table_entry_t *table_en;
171 uint64_t length;
172 uint8_t id;
173
174 length = 0;
175
176 id = dm_table_busy(head, DM_TABLE_ACTIVE);
177
178 /* Select active table */
179 tbl = &head->tables[id];
180
181 /*
182 * Find out what tables I want to select.
183 * if length => rawblkno then we should used that table.
184 */
5b279a20 185 SLIST_FOREACH(table_en, tbl, next) {
5b279a20 186 length += table_en->length;
5b279a20 187 }
ff56536e
AH
188
189 dm_table_unbusy(head);
190
191 return length;
192}
193/*
194 * Return > 0 if table is at least one table entry (returns number of entries)
195 * and return 0 if there is not. Target count returned from this function
196 * doesn't need to be true when userspace user receive it (after return
197 * there can be dm_dev_resume_ioctl), therfore this isonly informative.
198 */
199int
200dm_table_get_target_count(dm_table_head_t * head, uint8_t table_id)
201{
202 dm_table_entry_t *table_en;
203 dm_table_t *tbl;
204 uint32_t target_count;
205 uint8_t id;
206
207 target_count = 0;
208
209 id = dm_table_busy(head, table_id);
210
211 tbl = &head->tables[id];
212
213 SLIST_FOREACH(table_en, tbl, next)
214 target_count++;
215
216 dm_table_unbusy(head);
217
218 return target_count;
219}
220
221
222/*
223 * Initialize table_head structures, I'm trying to keep this structure as
224 * opaque as possible.
225 */
226void
227dm_table_head_init(dm_table_head_t * head)
228{
229 head->cur_active_table = 0;
230 head->io_cnt = 0;
231
232 /* Initialize tables. */
233 SLIST_INIT(&head->tables[0]);
234 SLIST_INIT(&head->tables[1]);
235
5b279a20 236 lockinit(&head->table_mtx, "dmtbl", 0, LK_CANRECURSE);
ff56536e
AH
237}
238/*
239 * Destroy all variables in table_head
240 */
241void
242dm_table_head_destroy(dm_table_head_t * head)
243{
5b279a20 244 KKASSERT(lockcount(&head->table_mtx) == 0);
8f77157d 245
ff56536e
AH
246 /* tables doens't exists when I call this routine, therefore it
247 * doesn't make sense to have io_cnt != 0 */
5b279a20 248 KKASSERT(head->io_cnt == 0);
ff56536e 249
5b279a20 250 lockuninit(&head->table_mtx);
ff56536e 251}