sys/dev/disk/dm/dm_target.c

   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/types.h>
  34 #include <sys/malloc.h>
  35 #include <sys/module.h>
  36 #include <sys/linker.h>
  37 #include <dev/disk/dm/dm.h>
  38
  39 #include "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->init == NULL) {
 145                 kprintf("dm: %s missing init\n", dm_target->name);
 146                 return EINVAL;
 147         }
 148         if (dm_target->destroy == NULL) {
 149                 kprintf("dm: %s missing destroy\n", dm_target->name);
 150                 return EINVAL;
 151         }
 152         if (dm_target->strategy == NULL) {
 153                 kprintf("dm: %s missing strategy\n", dm_target->name);
 154                 return EINVAL;
 155         }
 156
 157         lockmgr(&dm_target_mutex, LK_EXCLUSIVE);
 158
 159         dmt = dm_target_lookup_name(dm_target->name);
 160         if (dmt != NULL) {
 161                 kprintf("uhoh, target_insert EEXIST\n");
 162                 lockmgr(&dm_target_mutex, LK_RELEASE);
 163                 return EEXIST;
 164         }
 165         TAILQ_INSERT_TAIL(&dm_target_list, dm_target, dm_target_next);
 166
 167         lockmgr(&dm_target_mutex, LK_RELEASE);
 168
 169         return 0;
 170 }
 171
 172 /*
 173  * Remove target from TAILQ, target is selected with it's name.
 174  */
 175 int
 176 dm_target_remove(char *dm_target_name)
 177 {
 178         dm_target_t *dmt;
 179
 180         KKASSERT(dm_target_name != NULL);
 181
 182         lockmgr(&dm_target_mutex, LK_EXCLUSIVE);
 183
 184         dmt = dm_target_lookup_name(dm_target_name);
 185         if (dmt == NULL) {
 186                 lockmgr(&dm_target_mutex, LK_RELEASE);
 187                 return ENOENT;
 188         }
 189         if (dmt->ref_cnt > 0) {
 190                 lockmgr(&dm_target_mutex, LK_RELEASE);
 191                 return EBUSY;
 192         }
 193         TAILQ_REMOVE(&dm_target_list, dmt, dm_target_next);
 194
 195         lockmgr(&dm_target_mutex, LK_RELEASE);
 196
 197         dm_target_free(dmt);
 198
 199         return 0;
 200 }
 201
 202 /*
 203  * Allocate new target entry.
 204  */
 205 dm_target_t *
 206 dm_target_alloc(const char *name)
 207 {
 208         dm_target_t *dmt;
 209
 210         dmt = kmalloc(sizeof(*dmt), M_DM, M_WAITOK | M_ZERO);
 211         if (dmt == NULL)
 212                 return NULL;
 213
 214         if (name)
 215                 strlcpy(dmt->name, name, sizeof(dmt->name));
 216
 217         return dmt;
 218 }
 219
 220 int
 221 dm_target_free(dm_target_t *dmt)
 222 {
 223         KKASSERT(dmt != NULL);
 224
 225         kfree(dmt, M_DM);
 226
 227         return 0;
 228 }
 229
 230 /*
 231  * Return prop_array of dm_target dictionaries.
 232  */
 233 prop_array_t
 234 dm_target_prop_list(void)
 235 {
 236         prop_array_t target_array, ver;
 237         prop_dictionary_t target_dict;
 238         dm_target_t *dm_target;
 239
 240         size_t i;
 241
 242         target_array = prop_array_create();
 243
 244         lockmgr(&dm_target_mutex, LK_EXCLUSIVE);
 245
 246         TAILQ_FOREACH(dm_target, &dm_target_list, dm_target_next) {
 247
 248                 target_dict = prop_dictionary_create();
 249                 ver = prop_array_create();
 250                 prop_dictionary_set_cstring(target_dict, DM_TARGETS_NAME,
 251                     dm_target->name);
 252
 253                 for (i = 0; i < 3; i++)
 254                         prop_array_add_uint32(ver, dm_target->version[i]);
 255
 256                 prop_dictionary_set(target_dict, DM_TARGETS_VERSION, ver);
 257                 prop_array_add(target_array, target_dict);
 258
 259                 prop_object_release(ver);
 260                 prop_object_release(target_dict);
 261         }
 262
 263         lockmgr(&dm_target_mutex, LK_RELEASE);
 264
 265         return target_array;
 266 }
 267
 268 /*
 269  * Initialize dm_target subsystem.
 270  */
 271 int
 272 dm_target_init(void)
 273 {
 274         TAILQ_INIT(&dm_target_list);    /* initialize global target list */
 275         lockinit(&dm_target_mutex, "dmtrgt", 0, LK_CANRECURSE);
 276
 277         return 0;
 278 }
 279
 280 /*
 281  * Destroy all targets and remove them from queue.
 282  * This routine is called from dmdestroy, before module
 283  * is unloaded.
 284  */
 285 int
 286 dm_target_uninit(void)
 287 {
 288         dm_target_t *dm_target;
 289
 290         lockmgr(&dm_target_mutex, LK_EXCLUSIVE);
 291
 292         while ((dm_target = TAILQ_FIRST(&dm_target_list)) != NULL) {
 293                 TAILQ_REMOVE(&dm_target_list, dm_target, dm_target_next);
 294                 dm_target_free(dm_target);
 295         }
 296         KKASSERT(TAILQ_EMPTY(&dm_target_list));
 297
 298         lockmgr(&dm_target_mutex, LK_RELEASE);
 299
 300         lockuninit(&dm_target_mutex);
 301
 302         return 0;
 303 }