1 /* $NetBSD: dm_table.c,v 1.5 2010/01/04 00:19:08 haad Exp $ */
4 * Copyright (c) 2010-2011 Alex Hornung <alex@alexhornung.com>
5 * Copyright (c) 2008 The NetBSD Foundation, Inc.
8 * This code is derived from software contributed to The NetBSD Foundation
11 * Redistribution and use in source and binary forms, with or without
12 * modification, are permitted provided that the following conditions
14 * 1. Redistributions of source code must retain the above copyright
15 * notice, this list of conditions and the following disclaimer.
16 * 2. Redistributions in binary form must reproduce the above copyright
17 * notice, this list of conditions and the following disclaimer in the
18 * documentation and/or other materials provided with the distribution.
20 * THIS SOFTWARE IS PROVIDED BY THE NETBSD FOUNDATION, INC. AND CONTRIBUTORS
21 * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED
22 * TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
23 * PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE FOUNDATION OR CONTRIBUTORS
24 * BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
25 * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
26 * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
27 * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
28 * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
29 * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
30 * POSSIBILITY OF SUCH DAMAGE.
33 #include <sys/types.h>
35 #include <sys/malloc.h>
37 #include <dev/disk/dm/dm.h>
40 * There are two types of users of this interface:
43 * dmstrategy, dmgetdisklabel, dmsize, dm_dev_status_ioctl,
44 * dm_table_deps_ioctl, dm_table_status_ioctl, dm_table_reload_ioctl
47 * dm_dev_remove_ioctl, dm_dev_resume_ioctl, dm_table_clear_ioctl
49 * Writers can work with table_head only when there are no readers. We
50 * simply use shared/exclusive locking to ensure this.
54 * Function to increment table user reference counter. Return id
56 * DM_TABLE_ACTIVE will return active table id.
57 * DM_TABLE_INACTIVE will return inactive table id.
60 dm_table_busy(dm_table_head_t * head, uint8_t table_id)
66 lockmgr(&head->table_mtx, LK_SHARED);
68 if (table_id == DM_TABLE_ACTIVE)
69 id = head->cur_active_table;
71 id = 1 - head->cur_active_table;
73 atomic_add_int(&head->io_cnt, 1);
78 * Function release table lock and eventually wakeup all waiters.
81 dm_table_unbusy(dm_table_head_t * head)
83 KKASSERT(head->io_cnt != 0);
85 atomic_subtract_int(&head->io_cnt, 1);
87 lockmgr(&head->table_mtx, LK_RELEASE);
90 * Return current active table to caller, increment io_cnt reference counter.
93 dm_table_get_entry(dm_table_head_t * head, uint8_t table_id)
97 id = dm_table_busy(head, table_id);
99 return &head->tables[id];
102 * Decrement io reference counter and release shared lock.
105 dm_table_release(dm_table_head_t * head, uint8_t table_id)
107 dm_table_unbusy(head);
110 * Switch table from inactive to active mode. Have to wait until io_cnt is 0.
113 dm_table_switch_tables(dm_table_head_t * head)
115 lockmgr(&head->table_mtx, LK_EXCLUSIVE);
117 head->cur_active_table = 1 - head->cur_active_table;
119 lockmgr(&head->table_mtx, LK_RELEASE);
122 * Destroy all table data. This function can run when there are no
123 * readers on table lists.
126 dm_table_destroy(dm_table_head_t * head, uint8_t table_id)
129 dm_table_entry_t *table_en;
132 lockmgr(&head->table_mtx, LK_EXCLUSIVE);
134 aprint_debug("dm_Table_destroy called with %d--%d\n", table_id, head->io_cnt);
136 if (table_id == DM_TABLE_ACTIVE)
137 id = head->cur_active_table;
139 id = 1 - head->cur_active_table;
141 tbl = &head->tables[id];
143 while (!SLIST_EMPTY(tbl)) { /* List Deletion. */
144 table_en = SLIST_FIRST(tbl);
146 * Remove target specific config data. After successfull
147 * call table_en->target_config must be set to NULL.
149 table_en->target->destroy(table_en);
150 /* decrement the refcount for the target */
151 dm_target_unbusy(table_en->target);
153 SLIST_REMOVE_HEAD(tbl, next);
155 kfree(table_en, M_DM);
158 lockmgr(&head->table_mtx, LK_RELEASE);
163 * Return length of active or inactive table in device.
166 _dm_table_size(dm_table_head_t * head, int table)
169 dm_table_entry_t *table_en;
174 /* Select active table */
175 tbl = dm_table_get_entry(head, table);
178 * Find out what tables I want to select.
179 * if length => rawblkno then we should used that table.
181 SLIST_FOREACH(table_en, tbl, next) {
182 length += table_en->length;
185 dm_table_unbusy(head);
191 dm_table_size(dm_table_head_t *head)
193 return _dm_table_size(head, DM_TABLE_ACTIVE);
197 dm_inactive_table_size(dm_table_head_t *head)
199 return _dm_table_size(head, DM_TABLE_INACTIVE);
203 * Return > 0 if table is at least one table entry (returns number of entries)
204 * and return 0 if there is not. Target count returned from this function
205 * doesn't need to be true when userspace user receive it (after return
206 * there can be dm_dev_resume_ioctl), therfore this isonly informative.
209 dm_table_get_target_count(dm_table_head_t * head, uint8_t table_id)
211 dm_table_entry_t *table_en;
213 uint32_t target_count;
217 tbl = dm_table_get_entry(head, table_id);
219 SLIST_FOREACH(table_en, tbl, next)
222 dm_table_unbusy(head);
229 * Initialize table_head structures, I'm trying to keep this structure as
230 * opaque as possible.
233 dm_table_head_init(dm_table_head_t * head)
235 head->cur_active_table = 0;
238 /* Initialize tables. */
239 SLIST_INIT(&head->tables[0]);
240 SLIST_INIT(&head->tables[1]);
242 lockinit(&head->table_mtx, "dmtbl", 0, LK_CANRECURSE);
245 * Destroy all variables in table_head
248 dm_table_head_destroy(dm_table_head_t * head)
250 KKASSERT(lockcount(&head->table_mtx) == 0);
252 /* tables doens't exists when I call this routine, therefore it
253 * doesn't make sense to have io_cnt != 0 */
254 KKASSERT(head->io_cnt == 0);
256 lockuninit(&head->table_mtx);