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 aprint_debug("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 * Remove target specific config data. After successfull 147 * call table_en->target_config must be set to NULL. 148 */ 149 table_en->target->destroy(table_en); 150 151 dm_table_free_deps(table_en); 152 153 /* decrement the refcount for the target */ 154 dm_target_unbusy(table_en->target); 155 156 kfree(table_en, M_DM); 157 } 158 KKASSERT(TAILQ_EMPTY(tbl)); 159 160 lockmgr(&head->table_mtx, LK_RELEASE); 161 162 return 0; 163 } 164 /* 165 * Return length of active or inactive table in device. 166 */ 167 static uint64_t 168 _dm_table_size(dm_table_head_t *head, int table) 169 { 170 dm_table_t *tbl; 171 dm_table_entry_t *table_en; 172 uint64_t length; 173 174 length = 0; 175 176 /* Select active table */ 177 tbl = dm_table_get_entry(head, table); 178 179 /* 180 * Find out what tables I want to select. 181 * if length => rawblkno then we should used that table. 182 */ 183 TAILQ_FOREACH(table_en, tbl, next) { 184 length += table_en->length; 185 } 186 187 dm_table_unbusy(head); 188 189 return length; 190 } 191 192 uint64_t 193 dm_table_size(dm_table_head_t *head) 194 { 195 return _dm_table_size(head, DM_TABLE_ACTIVE); 196 } 197 198 uint64_t 199 dm_inactive_table_size(dm_table_head_t *head) 200 { 201 return _dm_table_size(head, DM_TABLE_INACTIVE); 202 } 203 204 /* 205 * Return > 0 if table is at least one table entry (returns number of entries) 206 * and return 0 if there is not. Target count returned from this function 207 * doesn't need to be true when userspace user receive it (after return 208 * there can be dm_dev_resume_ioctl), therfore this isonly informative. 209 */ 210 int 211 dm_table_get_target_count(dm_table_head_t *head, uint8_t table_id) 212 { 213 dm_table_entry_t *table_en; 214 dm_table_t *tbl; 215 uint32_t target_count; 216 217 target_count = 0; 218 219 tbl = dm_table_get_entry(head, table_id); 220 221 TAILQ_FOREACH(table_en, tbl, next) 222 target_count++; 223 224 dm_table_unbusy(head); 225 226 return target_count; 227 } 228 229 230 /* 231 * Initialize table_head structures, I'm trying to keep this structure as 232 * opaque as possible. 233 */ 234 void 235 dm_table_head_init(dm_table_head_t *head) 236 { 237 head->cur_active_table = 0; 238 head->io_cnt = 0; 239 240 /* Initialize tables. */ 241 TAILQ_INIT(&head->tables[0]); 242 TAILQ_INIT(&head->tables[1]); 243 244 lockinit(&head->table_mtx, "dmtbl", 0, LK_CANRECURSE); 245 } 246 /* 247 * Destroy all variables in table_head 248 */ 249 void 250 dm_table_head_destroy(dm_table_head_t *head) 251 { 252 KKASSERT(lockcount(&head->table_mtx) == 0); 253 254 /* tables doens't exists when I call this routine, therefore it 255 * doesn't make sense to have io_cnt != 0 */ 256 KKASSERT(head->io_cnt == 0); 257 258 lockuninit(&head->table_mtx); 259 } 260 261 void 262 dm_table_init_target(dm_table_entry_t *table_en, uint32_t type, void *cfg) 263 { 264 table_en->dev->dev_type = type; 265 table_en->target_config = cfg; 266 } 267 268 int 269 dm_table_add_deps(dm_table_entry_t *table_en, dm_pdev_t *pdev) 270 { 271 dm_table_head_t *head; 272 dm_mapping_t *map; 273 274 KKASSERT(pdev); 275 276 head = &table_en->dev->table_head; 277 lockmgr(&head->table_mtx, LK_SHARED); 278 279 TAILQ_FOREACH(map, &table_en->pdev_maps, next) { 280 if (map->data.pdev->udev == pdev->udev) { 281 lockmgr(&head->table_mtx, LK_RELEASE); 282 return -1; 283 } 284 } 285 286 map = kmalloc(sizeof(*map), M_DM, M_WAITOK | M_ZERO); 287 map->data.pdev = pdev; 288 TAILQ_INSERT_TAIL(&table_en->pdev_maps, map, next); 289 290 lockmgr(&head->table_mtx, LK_RELEASE); 291 292 return 0; 293 } 294 295 void 296 dm_table_free_deps(dm_table_entry_t *table_en) 297 { 298 dm_table_head_t *head; 299 dm_mapping_t *map; 300 301 head = &table_en->dev->table_head; 302 lockmgr(&head->table_mtx, LK_SHARED); 303 304 while ((map = TAILQ_FIRST(&table_en->pdev_maps)) != NULL) { 305 TAILQ_REMOVE(&table_en->pdev_maps, map, next); 306 kfree(map, M_DM); 307 } 308 KKASSERT(TAILQ_EMPTY(&table_en->pdev_maps)); 309 310 lockmgr(&head->table_mtx, LK_RELEASE); 311 } 312