1 /* $NetBSD: dm_table.c,v 1.5 2010/01/04 00:19:08 haad Exp $ */ 2 3 /* 4 * Copyright (c) 2010-2011 Alex Hornung <alex@alexhornung.com> 5 * Copyright (c) 2008 The NetBSD Foundation, Inc. 6 * All rights reserved. 7 * 8 * This code is derived from software contributed to The NetBSD Foundation 9 * by Adam Hamsik. 10 * 11 * Redistribution and use in source and binary forms, with or without 12 * modification, are permitted provided that the following conditions 13 * are met: 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. 19 * 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. 31 */ 32 33 #include <sys/types.h> 34 35 #include <sys/malloc.h> 36 37 #include <dev/disk/dm/dm.h> 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 * 49 * Writers can work with table_head only when there are no readers. We 50 * simply use shared/exclusive locking to ensure this. 51 */ 52 53 /* 54 * Function to increment table user reference counter. Return id 55 * of table_id table. 56 * DM_TABLE_ACTIVE will return active table id. 57 * DM_TABLE_INACTIVE will return inactive table id. 58 */ 59 static int 60 dm_table_busy(dm_table_head_t *head, uint8_t table_id) 61 { 62 uint8_t id; 63 64 id = 0; 65 66 lockmgr(&head->table_mtx, LK_SHARED); 67 68 if (table_id == DM_TABLE_ACTIVE) 69 id = head->cur_active_table; 70 else 71 id = 1 - head->cur_active_table; 72 73 atomic_add_int(&head->io_cnt, 1); 74 75 return id; 76 } 77 /* 78 * Function release table lock and eventually wakeup all waiters. 79 */ 80 static void 81 dm_table_unbusy(dm_table_head_t *head) 82 { 83 KKASSERT(head->io_cnt != 0); 84 85 atomic_subtract_int(&head->io_cnt, 1); 86 87 lockmgr(&head->table_mtx, LK_RELEASE); 88 } 89 /* 90 * Return current active table to caller, increment io_cnt reference counter. 91 */ 92 dm_table_t * 93 dm_table_get_entry(dm_table_head_t *head, uint8_t table_id) 94 { 95 uint8_t id; 96 97 id = dm_table_busy(head, table_id); 98 99 return &head->tables[id]; 100 } 101 /* 102 * Decrement io reference counter and release shared lock. 103 */ 104 void 105 dm_table_release(dm_table_head_t *head, uint8_t table_id) 106 { 107 dm_table_unbusy(head); 108 } 109 /* 110 * Switch table from inactive to active mode. Have to wait until io_cnt is 0. 111 */ 112 void 113 dm_table_switch_tables(dm_table_head_t *head) 114 { 115 lockmgr(&head->table_mtx, LK_EXCLUSIVE); 116 117 head->cur_active_table = 1 - head->cur_active_table; 118 119 lockmgr(&head->table_mtx, LK_RELEASE); 120 } 121 /* 122 * Destroy all table data. This function can run when there are no 123 * readers on table lists. 124 */ 125 int 126 dm_table_destroy(dm_table_head_t *head, uint8_t table_id) 127 { 128 dm_table_t *tbl; 129 dm_table_entry_t *table_en; 130 uint8_t id; 131 132 lockmgr(&head->table_mtx, LK_EXCLUSIVE); 133 134 dmdebug("dm_table_destroy called with %d--%d\n", table_id, head->io_cnt); 135 136 if (table_id == DM_TABLE_ACTIVE) 137 id = head->cur_active_table; 138 else 139 id = 1 - head->cur_active_table; 140 141 tbl = &head->tables[id]; 142 143 while ((table_en = TAILQ_FIRST(tbl)) != NULL) { 144 TAILQ_REMOVE(tbl, table_en, next); 145 146 if (table_en->target->destroy(table_en) == 0) 147 table_en->target_config = NULL; 148 149 dm_table_free_deps(table_en); 150 151 /* decrement the refcount for the target */ 152 dm_target_unbusy(table_en->target); 153 154 kfree(table_en, M_DM); 155 } 156 KKASSERT(TAILQ_EMPTY(tbl)); 157 158 lockmgr(&head->table_mtx, LK_RELEASE); 159 160 return 0; 161 } 162 /* 163 * Return length of active or inactive table in device. 164 */ 165 static uint64_t 166 _dm_table_size(dm_table_head_t *head, int table) 167 { 168 dm_table_t *tbl; 169 dm_table_entry_t *table_en; 170 uint64_t length; 171 172 length = 0; 173 174 /* Select active table */ 175 tbl = dm_table_get_entry(head, table); 176 177 /* 178 * Find out what tables I want to select. 179 * if length => rawblkno then we should used that table. 180 */ 181 TAILQ_FOREACH(table_en, tbl, next) { 182 length += table_en->length; 183 } 184 185 dm_table_unbusy(head); 186 187 return length; 188 } 189 190 uint64_t 191 dm_table_size(dm_table_head_t *head) 192 { 193 return _dm_table_size(head, DM_TABLE_ACTIVE); 194 } 195 196 uint64_t 197 dm_inactive_table_size(dm_table_head_t *head) 198 { 199 return _dm_table_size(head, DM_TABLE_INACTIVE); 200 } 201 202 /* 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. 207 */ 208 int 209 dm_table_get_target_count(dm_table_head_t *head, uint8_t table_id) 210 { 211 dm_table_entry_t *table_en; 212 dm_table_t *tbl; 213 uint32_t target_count; 214 215 target_count = 0; 216 217 tbl = dm_table_get_entry(head, table_id); 218 219 TAILQ_FOREACH(table_en, tbl, next) 220 target_count++; 221 222 dm_table_unbusy(head); 223 224 return target_count; 225 } 226 227 228 /* 229 * Initialize table_head structures, I'm trying to keep this structure as 230 * opaque as possible. 231 */ 232 void 233 dm_table_head_init(dm_table_head_t *head) 234 { 235 head->cur_active_table = 0; 236 head->io_cnt = 0; 237 238 /* Initialize tables. */ 239 TAILQ_INIT(&head->tables[0]); 240 TAILQ_INIT(&head->tables[1]); 241 242 lockinit(&head->table_mtx, "dmtbl", 0, LK_CANRECURSE); 243 } 244 /* 245 * Destroy all variables in table_head 246 */ 247 void 248 dm_table_head_destroy(dm_table_head_t *head) 249 { 250 KKASSERT(lockcount(&head->table_mtx) == 0); 251 252 /* 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); 255 256 lockuninit(&head->table_mtx); 257 } 258 259 void 260 dm_table_init_target(dm_table_entry_t *table_en, uint32_t type, void *cfg) 261 { 262 table_en->dev->dev_type = type; 263 table_en->target_config = cfg; 264 } 265 266 int 267 dm_table_add_deps(dm_table_entry_t *table_en, dm_pdev_t *pdev) 268 { 269 dm_table_head_t *head; 270 dm_mapping_t *map; 271 272 KKASSERT(pdev); 273 274 head = &table_en->dev->table_head; 275 lockmgr(&head->table_mtx, LK_SHARED); 276 277 TAILQ_FOREACH(map, &table_en->pdev_maps, next) { 278 if (map->data.pdev->udev == pdev->udev) { 279 lockmgr(&head->table_mtx, LK_RELEASE); 280 return -1; 281 } 282 } 283 284 map = kmalloc(sizeof(*map), M_DM, M_WAITOK | M_ZERO); 285 map->data.pdev = pdev; 286 TAILQ_INSERT_TAIL(&table_en->pdev_maps, map, next); 287 288 lockmgr(&head->table_mtx, LK_RELEASE); 289 290 return 0; 291 } 292 293 void 294 dm_table_free_deps(dm_table_entry_t *table_en) 295 { 296 dm_table_head_t *head; 297 dm_mapping_t *map; 298 299 head = &table_en->dev->table_head; 300 lockmgr(&head->table_mtx, LK_SHARED); 301 302 while ((map = TAILQ_FIRST(&table_en->pdev_maps)) != NULL) { 303 TAILQ_REMOVE(&table_en->pdev_maps, map, next); 304 kfree(map, M_DM); 305 } 306 KKASSERT(TAILQ_EMPTY(&table_en->pdev_maps)); 307 308 lockmgr(&head->table_mtx, LK_RELEASE); 309 } 310