1 /* $NetBSD: dm_target.c,v 1.12 2010/01/04 00:14:41 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/param.h> 34 #include <sys/malloc.h> 35 #include <sys/module.h> 36 #include <sys/linker.h> 37 #include <cpu/atomic.h> 38 #include <dev/disk/dm/dm.h> 39 #include <dev/disk/dm/netbsd-dm.h> 40 41 static dm_target_t *dm_target_lookup_name(const char *); 42 43 static TAILQ_HEAD(, dm_target) dm_target_list; 44 45 static struct lock dm_target_mutex; 46 47 void 48 dm_target_busy(dm_target_t *target) 49 { 50 atomic_add_int(&target->ref_cnt, 1); 51 } 52 53 /* 54 * Release reference counter on target. 55 */ 56 void 57 dm_target_unbusy(dm_target_t *target) 58 { 59 KKASSERT(target->ref_cnt > 0); 60 atomic_subtract_int(&target->ref_cnt, 1); 61 } 62 63 /* 64 * Try to autoload the module for the requested target. 65 */ 66 dm_target_t * 67 dm_target_autoload(const char *dm_target_name) 68 { 69 char mod_name[128]; 70 dm_target_t *dmt; 71 linker_file_t linker_file; 72 int error; 73 74 ksnprintf(mod_name, sizeof(mod_name), "dm_target_%s", dm_target_name); 75 error = linker_reference_module(mod_name, NULL, &linker_file); 76 if (error != 0) { 77 kprintf("dm: could not autoload module for target %s\n", 78 dm_target_name); 79 return NULL; 80 } 81 82 dmt = dm_target_lookup(dm_target_name); 83 if (dmt == NULL) { 84 linker_release_module(NULL, NULL, linker_file); 85 return NULL; 86 } 87 88 /* XXX: extra-big hack to allow users to kldunload the module */ 89 linker_file->userrefs = 1; 90 91 return dmt; 92 } 93 94 /* 95 * Lookup for target in global target list. 96 */ 97 dm_target_t * 98 dm_target_lookup(const char *dm_target_name) 99 { 100 dm_target_t *dmt; 101 102 dmt = NULL; 103 104 if (dm_target_name == NULL) 105 return NULL; 106 107 lockmgr(&dm_target_mutex, LK_EXCLUSIVE); 108 109 dmt = dm_target_lookup_name(dm_target_name); 110 if (dmt != NULL) 111 dm_target_busy(dmt); 112 113 lockmgr(&dm_target_mutex, LK_RELEASE); 114 115 return dmt; 116 } 117 118 /* 119 * Search for name in TAILQ and return apropriate pointer. 120 */ 121 static dm_target_t * 122 dm_target_lookup_name(const char *dm_target_name) 123 { 124 dm_target_t *dm_target; 125 126 TAILQ_FOREACH(dm_target, &dm_target_list, dm_target_next) { 127 if (strcmp(dm_target_name, dm_target->name) == 0) 128 return dm_target; 129 } 130 131 return NULL; 132 } 133 134 /* 135 * Insert new target struct into the TAILQ. 136 * dm_target contains name, version, function pointer to specific target 137 * functions. 138 */ 139 int 140 dm_target_insert(dm_target_t *dm_target) 141 { 142 dm_target_t *dmt; 143 144 if (dm_target->strategy == NULL) { 145 kprintf("dm: %s missing strategy\n", dm_target->name); 146 return EINVAL; 147 } 148 149 lockmgr(&dm_target_mutex, LK_EXCLUSIVE); 150 151 dmt = dm_target_lookup_name(dm_target->name); 152 if (dmt != NULL) { 153 kprintf("uhoh, target_insert EEXIST\n"); 154 lockmgr(&dm_target_mutex, LK_RELEASE); 155 return EEXIST; 156 } 157 TAILQ_INSERT_TAIL(&dm_target_list, dm_target, dm_target_next); 158 159 lockmgr(&dm_target_mutex, LK_RELEASE); 160 161 return 0; 162 } 163 164 /* 165 * Remove target from TAILQ, target is selected with it's name. 166 */ 167 int 168 dm_target_remove(char *dm_target_name) 169 { 170 dm_target_t *dmt; 171 172 KKASSERT(dm_target_name != NULL); 173 174 lockmgr(&dm_target_mutex, LK_EXCLUSIVE); 175 176 dmt = dm_target_lookup_name(dm_target_name); 177 if (dmt == NULL) { 178 lockmgr(&dm_target_mutex, LK_RELEASE); 179 return ENOENT; 180 } 181 if (dmt->ref_cnt > 0) { 182 lockmgr(&dm_target_mutex, LK_RELEASE); 183 return EBUSY; 184 } 185 TAILQ_REMOVE(&dm_target_list, dmt, dm_target_next); 186 187 lockmgr(&dm_target_mutex, LK_RELEASE); 188 189 dm_target_free(dmt); 190 191 return 0; 192 } 193 194 /* 195 * Allocate new target entry. 196 */ 197 dm_target_t * 198 dm_target_alloc(const char *name) 199 { 200 dm_target_t *dmt; 201 202 dmt = kmalloc(sizeof(*dmt), M_DM, M_WAITOK | M_ZERO); 203 if (dmt == NULL) 204 return NULL; 205 206 if (name) 207 strlcpy(dmt->name, name, sizeof(dmt->name)); 208 209 return dmt; 210 } 211 212 int 213 dm_target_free(dm_target_t *dmt) 214 { 215 KKASSERT(dmt != NULL); 216 217 kfree(dmt, M_DM); 218 219 return 0; 220 } 221 222 /* 223 * Return prop_array of dm_target dictionaries. 224 */ 225 prop_array_t 226 dm_target_prop_list(void) 227 { 228 prop_array_t target_array, ver; 229 prop_dictionary_t target_dict; 230 dm_target_t *dm_target; 231 232 size_t i; 233 234 target_array = prop_array_create(); 235 236 lockmgr(&dm_target_mutex, LK_EXCLUSIVE); 237 238 TAILQ_FOREACH(dm_target, &dm_target_list, dm_target_next) { 239 240 target_dict = prop_dictionary_create(); 241 ver = prop_array_create(); 242 prop_dictionary_set_cstring(target_dict, DM_TARGETS_NAME, 243 dm_target->name); 244 245 for (i = 0; i < 3; i++) 246 prop_array_add_uint32(ver, dm_target->version[i]); 247 248 prop_dictionary_set(target_dict, DM_TARGETS_VERSION, ver); 249 prop_array_add(target_array, target_dict); 250 251 prop_object_release(ver); 252 prop_object_release(target_dict); 253 } 254 255 lockmgr(&dm_target_mutex, LK_RELEASE); 256 257 return target_array; 258 } 259 260 /* 261 * Initialize dm_target subsystem. 262 */ 263 int 264 dm_target_init(void) 265 { 266 TAILQ_INIT(&dm_target_list); /* initialize global target list */ 267 lockinit(&dm_target_mutex, "dmtrgt", 0, LK_CANRECURSE); 268 269 return 0; 270 } 271 272 /* 273 * Destroy all targets and remove them from queue. 274 * This routine is called from dmdestroy, before module 275 * is unloaded. 276 */ 277 int 278 dm_target_uninit(void) 279 { 280 dm_target_t *dm_target; 281 282 lockmgr(&dm_target_mutex, LK_EXCLUSIVE); 283 284 while ((dm_target = TAILQ_FIRST(&dm_target_list)) != NULL) { 285 TAILQ_REMOVE(&dm_target_list, dm_target, dm_target_next); 286 dm_target_free(dm_target); 287 } 288 KKASSERT(TAILQ_EMPTY(&dm_target_list)); 289 290 lockmgr(&dm_target_mutex, LK_RELEASE); 291 292 lockuninit(&dm_target_mutex); 293 294 return 0; 295 } 296