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