drivers/target/target_core_tpg.c

   1 /*******************************************************************************
   2  * Filename:  target_core_tpg.c
   3  *
   4  * This file contains generic Target Portal Group related functions.
   5  *
   6  * (c) Copyright 2002-2013 Datera, Inc.
   7  *
   8  * Nicholas A. Bellinger <nab@kernel.org>
   9  *
  10  * This program is free software; you can redistribute it and/or modify
  11  * it under the terms of the GNU General Public License as published by
  12  * the Free Software Foundation; either version 2 of the License, or
  13  * (at your option) any later version.
  14  *
  15  * This program is distributed in the hope that it will be useful,
  16  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  17  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  18  * GNU General Public License for more details.
  19  *
  20  * You should have received a copy of the GNU General Public License
  21  * along with this program; if not, write to the Free Software
  22  * Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
  23  *
  24  ******************************************************************************/
  25
  26 #include <linux/net.h>
  27 #include <linux/string.h>
  28 #include <linux/timer.h>
  29 #include <linux/slab.h>
  30 #include <linux/spinlock.h>
  31 #include <linux/in.h>
  32 #include <linux/export.h>
  33 #include <net/sock.h>
  34 #include <net/tcp.h>
  35 #include <scsi/scsi_proto.h>
  36
  37 #include <target/target_core_base.h>
  38 #include <target/target_core_backend.h>
  39 #include <target/target_core_fabric.h>
  40
  41 #include "target_core_internal.h"
  42 #include "target_core_alua.h"
  43 #include "target_core_pr.h"
  44 #include "target_core_ua.h"
  45
  46 extern struct se_device *g_lun0_dev;
  47
  48 static DEFINE_SPINLOCK(tpg_lock);
  49 static LIST_HEAD(tpg_list);
  50
  51 /*      __core_tpg_get_initiator_node_acl():
  52  *
  53  *      mutex_lock(&tpg->acl_node_mutex); must be held when calling
  54  */
  55 struct se_node_acl *__core_tpg_get_initiator_node_acl(
  56         struct se_portal_group *tpg,
  57         const char *initiatorname)
  58 {
  59         struct se_node_acl *acl;
  60
  61         list_for_each_entry(acl, &tpg->acl_node_list, acl_list) {
  62                 if (!strcmp(acl->initiatorname, initiatorname))
  63                         return acl;
  64         }
  65
  66         return NULL;
  67 }
  68
  69 /*      core_tpg_get_initiator_node_acl():
  70  *
  71  *
  72  */
  73 struct se_node_acl *core_tpg_get_initiator_node_acl(
  74         struct se_portal_group *tpg,
  75         unsigned char *initiatorname)
  76 {
  77         struct se_node_acl *acl;
  78         /*
  79          * Obtain se_node_acl->acl_kref using fabric driver provided
  80          * initiatorname[] during node acl endpoint lookup driven by
  81          * new se_session login.
  82          *
  83          * The reference is held until se_session shutdown -> release
  84          * occurs via fabric driver invoked transport_deregister_session()
  85          * or transport_free_session() code.
  86          */
  87         mutex_lock(&tpg->acl_node_mutex);
  88         acl = __core_tpg_get_initiator_node_acl(tpg, initiatorname);
  89         if (acl) {
  90                 if (!kref_get_unless_zero(&acl->acl_kref))
  91                         acl = NULL;
  92         }
  93         mutex_unlock(&tpg->acl_node_mutex);
  94
  95         return acl;
  96 }
  97 EXPORT_SYMBOL(core_tpg_get_initiator_node_acl);
  98
  99 void core_allocate_nexus_loss_ua(
 100         struct se_node_acl *nacl)
 101 {
 102         struct se_dev_entry *deve;
 103
 104         if (!nacl)
 105                 return;
 106
 107         rcu_read_lock();
 108         hlist_for_each_entry_rcu(deve, &nacl->lun_entry_hlist, link)
 109                 core_scsi3_ua_allocate(deve, 0x29,
 110                         ASCQ_29H_NEXUS_LOSS_OCCURRED);
 111         rcu_read_unlock();
 112 }
 113 EXPORT_SYMBOL(core_allocate_nexus_loss_ua);
 114
 115 /*      core_tpg_add_node_to_devs():
 116  *
 117  *
 118  */
 119 void core_tpg_add_node_to_devs(
 120         struct se_node_acl *acl,
 121         struct se_portal_group *tpg,
 122         struct se_lun *lun_orig)
 123 {
 124         bool lun_access_ro = true;
 125         struct se_lun *lun;
 126         struct se_device *dev;
 127
 128         mutex_lock(&tpg->tpg_lun_mutex);
 129         hlist_for_each_entry_rcu(lun, &tpg->tpg_lun_hlist, link) {
 130                 if (lun_orig && lun != lun_orig)
 131                         continue;
 132
 133                 dev = rcu_dereference_check(lun->lun_se_dev,
 134                                             lockdep_is_held(&tpg->tpg_lun_mutex));
 135                 /*
 136                  * By default in LIO-Target $FABRIC_MOD,
 137                  * demo_mode_write_protect is ON, or READ_ONLY;
 138                  */
 139                 if (!tpg->se_tpg_tfo->tpg_check_demo_mode_write_protect(tpg)) {
 140                         lun_access_ro = false;
 141                 } else {
 142                         /*
 143                          * Allow only optical drives to issue R/W in default RO
 144                          * demo mode.
 145                          */
 146                         if (dev->transport->get_device_type(dev) == TYPE_DISK)
 147                                 lun_access_ro = true;
 148                         else
 149                                 lun_access_ro = false;
 150                 }
 151
 152                 pr_debug("TARGET_CORE[%s]->TPG[%u]_LUN[%llu] - Adding %s"
 153                         " access for LUN in Demo Mode\n",
 154                         tpg->se_tpg_tfo->get_fabric_name(),
 155                         tpg->se_tpg_tfo->tpg_get_tag(tpg), lun->unpacked_lun,
 156                         lun_access_ro ? "READ-ONLY" : "READ-WRITE");
 157
 158                 core_enable_device_list_for_node(lun, NULL, lun->unpacked_lun,
 159                                                  lun_access_ro, acl, tpg);
 160                 /*
 161                  * Check to see if there are any existing persistent reservation
 162                  * APTPL pre-registrations that need to be enabled for this dynamic
 163                  * LUN ACL now..
 164                  */
 165                 core_scsi3_check_aptpl_registration(dev, tpg, lun, acl,
 166                                                     lun->unpacked_lun);
 167         }
 168         mutex_unlock(&tpg->tpg_lun_mutex);
 169 }
 170
 171 static void
 172 target_set_nacl_queue_depth(struct se_portal_group *tpg,
 173                             struct se_node_acl *acl, u32 queue_depth)
 174 {
 175         acl->queue_depth = queue_depth;
 176
 177         if (!acl->queue_depth) {
 178                 pr_warn("Queue depth for %s Initiator Node: %s is 0,"
 179                         "defaulting to 1.\n", tpg->se_tpg_tfo->get_fabric_name(),
 180                         acl->initiatorname);
 181                 acl->queue_depth = 1;
 182         }
 183 }
 184
 185 static struct se_node_acl *target_alloc_node_acl(struct se_portal_group *tpg,
 186                 const unsigned char *initiatorname)
 187 {
 188         struct se_node_acl *acl;
 189         u32 queue_depth;
 190
 191         acl = kzalloc(max(sizeof(*acl), tpg->se_tpg_tfo->node_acl_size),
 192                         GFP_KERNEL);
 193         if (!acl)
 194                 return NULL;
 195
 196         INIT_LIST_HEAD(&acl->acl_list);
 197         INIT_LIST_HEAD(&acl->acl_sess_list);
 198         INIT_HLIST_HEAD(&acl->lun_entry_hlist);
 199         kref_init(&acl->acl_kref);
 200         init_completion(&acl->acl_free_comp);
 201         spin_lock_init(&acl->nacl_sess_lock);
 202         mutex_init(&acl->lun_entry_mutex);
 203         atomic_set(&acl->acl_pr_ref_count, 0);
 204
 205         if (tpg->se_tpg_tfo->tpg_get_default_depth)
 206                 queue_depth = tpg->se_tpg_tfo->tpg_get_default_depth(tpg);
 207         else
 208                 queue_depth = 1;
 209         target_set_nacl_queue_depth(tpg, acl, queue_depth);
 210
 211         snprintf(acl->initiatorname, TRANSPORT_IQN_LEN, "%s", initiatorname);
 212         acl->se_tpg = tpg;
 213         acl->acl_index = scsi_get_new_index(SCSI_AUTH_INTR_INDEX);
 214
 215         tpg->se_tpg_tfo->set_default_node_attributes(acl);
 216
 217         return acl;
 218 }
 219
 220 static void target_add_node_acl(struct se_node_acl *acl)
 221 {
 222         struct se_portal_group *tpg = acl->se_tpg;
 223
 224         mutex_lock(&tpg->acl_node_mutex);
 225         list_add_tail(&acl->acl_list, &tpg->acl_node_list);
 226         mutex_unlock(&tpg->acl_node_mutex);
 227
 228         pr_debug("%s_TPG[%hu] - Added %s ACL with TCQ Depth: %d for %s"
 229                 " Initiator Node: %s\n",
 230                 tpg->se_tpg_tfo->get_fabric_name(),
 231                 tpg->se_tpg_tfo->tpg_get_tag(tpg),
 232                 acl->dynamic_node_acl ? "DYNAMIC" : "",
 233                 acl->queue_depth,
 234                 tpg->se_tpg_tfo->get_fabric_name(),
 235                 acl->initiatorname);
 236 }
 237
 238 bool target_tpg_has_node_acl(struct se_portal_group *tpg,
 239                              const char *initiatorname)
 240 {
 241         struct se_node_acl *acl;
 242         bool found = false;
 243
 244         mutex_lock(&tpg->acl_node_mutex);
 245         list_for_each_entry(acl, &tpg->acl_node_list, acl_list) {
 246                 if (!strcmp(acl->initiatorname, initiatorname)) {
 247                         found = true;
 248                         break;
 249                 }
 250         }
 251         mutex_unlock(&tpg->acl_node_mutex);
 252
 253         return found;
 254 }
 255 EXPORT_SYMBOL(target_tpg_has_node_acl);
 256
 257 struct se_node_acl *core_tpg_check_initiator_node_acl(
 258         struct se_portal_group *tpg,
 259         unsigned char *initiatorname)
 260 {
 261         struct se_node_acl *acl;
 262
 263         acl = core_tpg_get_initiator_node_acl(tpg, initiatorname);
 264         if (acl)
 265                 return acl;
 266
 267         if (!tpg->se_tpg_tfo->tpg_check_demo_mode(tpg))
 268                 return NULL;
 269
 270         acl = target_alloc_node_acl(tpg, initiatorname);
 271         if (!acl)
 272                 return NULL;
 273         /*
 274          * When allocating a dynamically generated node_acl, go ahead
 275          * and take the extra kref now before returning to the fabric
 276          * driver caller.
 277          *
 278          * Note this reference will be released at session shutdown
 279          * time within transport_free_session() code.
 280          */
 281         kref_get(&acl->acl_kref);
 282         acl->dynamic_node_acl = 1;
 283
 284         /*
 285          * Here we only create demo-mode MappedLUNs from the active
 286          * TPG LUNs if the fabric is not explicitly asking for
 287          * tpg_check_demo_mode_login_only() == 1.
 288          */
 289         if ((tpg->se_tpg_tfo->tpg_check_demo_mode_login_only == NULL) ||
 290             (tpg->se_tpg_tfo->tpg_check_demo_mode_login_only(tpg) != 1))
 291                 core_tpg_add_node_to_devs(acl, tpg, NULL);
 292
 293         target_add_node_acl(acl);
 294         return acl;
 295 }
 296 EXPORT_SYMBOL(core_tpg_check_initiator_node_acl);
 297
 298 void core_tpg_wait_for_nacl_pr_ref(struct se_node_acl *nacl)
 299 {
 300         while (atomic_read(&nacl->acl_pr_ref_count) != 0)
 301                 cpu_relax();
 302 }
 303
 304 struct se_node_acl *core_tpg_add_initiator_node_acl(
 305         struct se_portal_group *tpg,
 306         const char *initiatorname)
 307 {
 308         struct se_node_acl *acl;
 309
 310         mutex_lock(&tpg->acl_node_mutex);
 311         acl = __core_tpg_get_initiator_node_acl(tpg, initiatorname);
 312         if (acl) {
 313                 if (acl->dynamic_node_acl) {
 314                         acl->dynamic_node_acl = 0;
 315                         pr_debug("%s_TPG[%u] - Replacing dynamic ACL"
 316                                 " for %s\n", tpg->se_tpg_tfo->get_fabric_name(),
 317                                 tpg->se_tpg_tfo->tpg_get_tag(tpg), initiatorname);
 318                         mutex_unlock(&tpg->acl_node_mutex);
 319                         return acl;
 320                 }
 321
 322                 pr_err("ACL entry for %s Initiator"
 323                         " Node %s already exists for TPG %u, ignoring"
 324                         " request.\n",  tpg->se_tpg_tfo->get_fabric_name(),
 325                         initiatorname, tpg->se_tpg_tfo->tpg_get_tag(tpg));
 326                 mutex_unlock(&tpg->acl_node_mutex);
 327                 return ERR_PTR(-EEXIST);
 328         }
 329         mutex_unlock(&tpg->acl_node_mutex);
 330
 331         acl = target_alloc_node_acl(tpg, initiatorname);
 332         if (!acl)
 333                 return ERR_PTR(-ENOMEM);
 334
 335         target_add_node_acl(acl);
 336         return acl;
 337 }
 338
 339 static void target_shutdown_sessions(struct se_node_acl *acl)
 340 {
 341         struct se_session *sess;
 342         unsigned long flags;
 343
 344 restart:
 345         spin_lock_irqsave(&acl->nacl_sess_lock, flags);
 346         list_for_each_entry(sess, &acl->acl_sess_list, sess_acl_list) {
 347                 if (sess->sess_tearing_down)
 348                         continue;
 349
 350                 list_del_init(&sess->sess_acl_list);
 351                 spin_unlock_irqrestore(&acl->nacl_sess_lock, flags);
 352
 353                 if (acl->se_tpg->se_tpg_tfo->close_session)
 354                         acl->se_tpg->se_tpg_tfo->close_session(sess);
 355                 goto restart;
 356         }
 357         spin_unlock_irqrestore(&acl->nacl_sess_lock, flags);
 358 }
 359
 360 void core_tpg_del_initiator_node_acl(struct se_node_acl *acl)
 361 {
 362         struct se_portal_group *tpg = acl->se_tpg;
 363
 364         mutex_lock(&tpg->acl_node_mutex);
 365         if (acl->dynamic_node_acl)
 366                 acl->dynamic_node_acl = 0;
 367         list_del(&acl->acl_list);
 368         mutex_unlock(&tpg->acl_node_mutex);
 369
 370         target_shutdown_sessions(acl);
 371
 372         target_put_nacl(acl);
 373         /*
 374          * Wait for last target_put_nacl() to complete in target_complete_nacl()
 375          * for active fabric session transport_deregister_session() callbacks.
 376          */
 377         wait_for_completion(&acl->acl_free_comp);
 378
 379         core_tpg_wait_for_nacl_pr_ref(acl);
 380         core_free_device_list_for_node(acl, tpg);
 381
 382         pr_debug("%s_TPG[%hu] - Deleted ACL with TCQ Depth: %d for %s"
 383                 " Initiator Node: %s\n", tpg->se_tpg_tfo->get_fabric_name(),
 384                 tpg->se_tpg_tfo->tpg_get_tag(tpg), acl->queue_depth,
 385                 tpg->se_tpg_tfo->get_fabric_name(), acl->initiatorname);
 386
 387         kfree(acl);
 388 }
 389
 390 /*      core_tpg_set_initiator_node_queue_depth():
 391  *
 392  *
 393  */
 394 int core_tpg_set_initiator_node_queue_depth(
 395         struct se_node_acl *acl,
 396         u32 queue_depth)
 397 {
 398         struct se_portal_group *tpg = acl->se_tpg;
 399
 400         /*
 401          * User has requested to change the queue depth for a Initiator Node.
 402          * Change the value in the Node's struct se_node_acl, and call
 403          * target_set_nacl_queue_depth() to set the new queue depth.
 404          */
 405         target_set_nacl_queue_depth(tpg, acl, queue_depth);
 406
 407         /*
 408          * Shutdown all pending sessions to force session reinstatement.
 409          */
 410         target_shutdown_sessions(acl);
 411
 412         pr_debug("Successfully changed queue depth to: %d for Initiator"
 413                 " Node: %s on %s Target Portal Group: %u\n", acl->queue_depth,
 414                 acl->initiatorname, tpg->se_tpg_tfo->get_fabric_name(),
 415                 tpg->se_tpg_tfo->tpg_get_tag(tpg));
 416
 417         return 0;
 418 }
 419 EXPORT_SYMBOL(core_tpg_set_initiator_node_queue_depth);
 420
 421 /*      core_tpg_set_initiator_node_tag():
 422  *
 423  *      Initiator nodeacl tags are not used internally, but may be used by
 424  *      userspace to emulate aliases or groups.
 425  *      Returns length of newly-set tag or -EINVAL.
 426  */
 427 int core_tpg_set_initiator_node_tag(
 428         struct se_portal_group *tpg,
 429         struct se_node_acl *acl,
 430         const char *new_tag)
 431 {
 432         if (strlen(new_tag) >= MAX_ACL_TAG_SIZE)
 433                 return -EINVAL;
 434
 435         if (!strncmp("NULL", new_tag, 4)) {
 436                 acl->acl_tag[0] = '\0';
 437                 return 0;
 438         }
 439
 440         return snprintf(acl->acl_tag, MAX_ACL_TAG_SIZE, "%s", new_tag);
 441 }
 442 EXPORT_SYMBOL(core_tpg_set_initiator_node_tag);
 443
 444 static void core_tpg_lun_ref_release(struct percpu_ref *ref)
 445 {
 446         struct se_lun *lun = container_of(ref, struct se_lun, lun_ref);
 447
 448         complete(&lun->lun_ref_comp);
 449 }
 450
 451 int core_tpg_register(
 452         struct se_wwn *se_wwn,
 453         struct se_portal_group *se_tpg,
 454         int proto_id)
 455 {
 456         int ret;
 457
 458         if (!se_tpg)
 459                 return -EINVAL;
 460         /*
 461          * For the typical case where core_tpg_register() is called by a
 462          * fabric driver from target_core_fabric_ops->fabric_make_tpg()
 463          * configfs context, use the original tf_ops pointer already saved
 464          * by target-core in target_fabric_make_wwn().
 465          *
 466          * Otherwise, for special cases like iscsi-target discovery TPGs
 467          * the caller is responsible for setting ->se_tpg_tfo ahead of
 468          * calling core_tpg_register().
 469          */
 470         if (se_wwn)
 471                 se_tpg->se_tpg_tfo = se_wwn->wwn_tf->tf_ops;
 472
 473         if (!se_tpg->se_tpg_tfo) {
 474                 pr_err("Unable to locate se_tpg->se_tpg_tfo pointer\n");
 475                 return -EINVAL;
 476         }
 477
 478         INIT_HLIST_HEAD(&se_tpg->tpg_lun_hlist);
 479         se_tpg->proto_id = proto_id;
 480         se_tpg->se_tpg_wwn = se_wwn;
 481         atomic_set(&se_tpg->tpg_pr_ref_count, 0);
 482         INIT_LIST_HEAD(&se_tpg->acl_node_list);
 483         INIT_LIST_HEAD(&se_tpg->se_tpg_node);
 484         INIT_LIST_HEAD(&se_tpg->tpg_sess_list);
 485         spin_lock_init(&se_tpg->session_lock);
 486         mutex_init(&se_tpg->tpg_lun_mutex);
 487         mutex_init(&se_tpg->acl_node_mutex);
 488
 489         if (se_tpg->proto_id >= 0) {
 490                 se_tpg->tpg_virt_lun0 = core_tpg_alloc_lun(se_tpg, 0);
 491                 if (IS_ERR(se_tpg->tpg_virt_lun0))
 492                         return PTR_ERR(se_tpg->tpg_virt_lun0);
 493
 494                 ret = core_tpg_add_lun(se_tpg, se_tpg->tpg_virt_lun0,
 495                                 true, g_lun0_dev);
 496                 if (ret < 0) {
 497                         kfree(se_tpg->tpg_virt_lun0);
 498                         return ret;
 499                 }
 500         }
 501
 502         spin_lock_bh(&tpg_lock);
 503         list_add_tail(&se_tpg->se_tpg_node, &tpg_list);
 504         spin_unlock_bh(&tpg_lock);
 505
 506         pr_debug("TARGET_CORE[%s]: Allocated portal_group for endpoint: %s, "
 507                  "Proto: %d, Portal Tag: %u\n", se_tpg->se_tpg_tfo->get_fabric_name(),
 508                 se_tpg->se_tpg_tfo->tpg_get_wwn(se_tpg) ?
 509                 se_tpg->se_tpg_tfo->tpg_get_wwn(se_tpg) : NULL,
 510                 se_tpg->proto_id, se_tpg->se_tpg_tfo->tpg_get_tag(se_tpg));
 511
 512         return 0;
 513 }
 514 EXPORT_SYMBOL(core_tpg_register);
 515
 516 int core_tpg_deregister(struct se_portal_group *se_tpg)
 517 {
 518         const struct target_core_fabric_ops *tfo = se_tpg->se_tpg_tfo;
 519         struct se_node_acl *nacl, *nacl_tmp;
 520         LIST_HEAD(node_list);
 521
 522         pr_debug("TARGET_CORE[%s]: Deallocating portal_group for endpoint: %s, "
 523                  "Proto: %d, Portal Tag: %u\n", tfo->get_fabric_name(),
 524                 tfo->tpg_get_wwn(se_tpg) ? tfo->tpg_get_wwn(se_tpg) : NULL,
 525                 se_tpg->proto_id, tfo->tpg_get_tag(se_tpg));
 526
 527         spin_lock_bh(&tpg_lock);
 528         list_del(&se_tpg->se_tpg_node);
 529         spin_unlock_bh(&tpg_lock);
 530
 531         while (atomic_read(&se_tpg->tpg_pr_ref_count) != 0)
 532                 cpu_relax();
 533
 534         mutex_lock(&se_tpg->acl_node_mutex);
 535         list_splice_init(&se_tpg->acl_node_list, &node_list);
 536         mutex_unlock(&se_tpg->acl_node_mutex);
 537         /*
 538          * Release any remaining demo-mode generated se_node_acl that have
 539          * not been released because of TFO->tpg_check_demo_mode_cache() == 1
 540          * in transport_deregister_session().
 541          */
 542         list_for_each_entry_safe(nacl, nacl_tmp, &node_list, acl_list) {
 543                 list_del(&nacl->acl_list);
 544
 545                 core_tpg_wait_for_nacl_pr_ref(nacl);
 546                 core_free_device_list_for_node(nacl, se_tpg);
 547                 kfree(nacl);
 548         }
 549
 550         if (se_tpg->proto_id >= 0) {
 551                 core_tpg_remove_lun(se_tpg, se_tpg->tpg_virt_lun0);
 552                 kfree_rcu(se_tpg->tpg_virt_lun0, rcu_head);
 553         }
 554
 555         return 0;
 556 }
 557 EXPORT_SYMBOL(core_tpg_deregister);
 558
 559 struct se_lun *core_tpg_alloc_lun(
 560         struct se_portal_group *tpg,
 561         u64 unpacked_lun)
 562 {
 563         struct se_lun *lun;
 564
 565         lun = kzalloc(sizeof(*lun), GFP_KERNEL);
 566         if (!lun) {
 567                 pr_err("Unable to allocate se_lun memory\n");
 568                 return ERR_PTR(-ENOMEM);
 569         }
 570         lun->unpacked_lun = unpacked_lun;
 571         lun->lun_link_magic = SE_LUN_LINK_MAGIC;
 572         atomic_set(&lun->lun_acl_count, 0);
 573         init_completion(&lun->lun_ref_comp);
 574         INIT_LIST_HEAD(&lun->lun_deve_list);
 575         INIT_LIST_HEAD(&lun->lun_dev_link);
 576         atomic_set(&lun->lun_tg_pt_secondary_offline, 0);
 577         spin_lock_init(&lun->lun_deve_lock);
 578         mutex_init(&lun->lun_tg_pt_md_mutex);
 579         INIT_LIST_HEAD(&lun->lun_tg_pt_gp_link);
 580         spin_lock_init(&lun->lun_tg_pt_gp_lock);
 581         lun->lun_tpg = tpg;
 582
 583         return lun;
 584 }
 585
 586 int core_tpg_add_lun(
 587         struct se_portal_group *tpg,
 588         struct se_lun *lun,
 589         bool lun_access_ro,
 590         struct se_device *dev)
 591 {
 592         int ret;
 593
 594         ret = percpu_ref_init(&lun->lun_ref, core_tpg_lun_ref_release, 0,
 595                               GFP_KERNEL);
 596         if (ret < 0)
 597                 goto out;
 598
 599         ret = core_alloc_rtpi(lun, dev);
 600         if (ret)
 601                 goto out_kill_ref;
 602
 603         if (!(dev->transport->transport_flags & TRANSPORT_FLAG_PASSTHROUGH) &&
 604             !(dev->se_hba->hba_flags & HBA_FLAGS_INTERNAL_USE))
 605                 target_attach_tg_pt_gp(lun, dev->t10_alua.default_tg_pt_gp);
 606
 607         mutex_lock(&tpg->tpg_lun_mutex);
 608
 609         spin_lock(&dev->se_port_lock);
 610         lun->lun_index = dev->dev_index;
 611         rcu_assign_pointer(lun->lun_se_dev, dev);
 612         dev->export_count++;
 613         list_add_tail(&lun->lun_dev_link, &dev->dev_sep_list);
 614         spin_unlock(&dev->se_port_lock);
 615
 616         if (dev->dev_flags & DF_READ_ONLY)
 617                 lun->lun_access_ro = true;
 618         else
 619                 lun->lun_access_ro = lun_access_ro;
 620         if (!(dev->se_hba->hba_flags & HBA_FLAGS_INTERNAL_USE))
 621                 hlist_add_head_rcu(&lun->link, &tpg->tpg_lun_hlist);
 622         mutex_unlock(&tpg->tpg_lun_mutex);
 623
 624         return 0;
 625
 626 out_kill_ref:
 627         percpu_ref_exit(&lun->lun_ref);
 628 out:
 629         return ret;
 630 }
 631
 632 void core_tpg_remove_lun(
 633         struct se_portal_group *tpg,
 634         struct se_lun *lun)
 635 {
 636         /*
 637          * rcu_dereference_raw protected by se_lun->lun_group symlink
 638          * reference to se_device->dev_group.
 639          */
 640         struct se_device *dev = rcu_dereference_raw(lun->lun_se_dev);
 641
 642         core_clear_lun_from_tpg(lun, tpg);
 643         /*
 644          * Wait for any active I/O references to percpu se_lun->lun_ref to
 645          * be released.  Also, se_lun->lun_ref is now used by PR and ALUA
 646          * logic when referencing a remote target port during ALL_TGT_PT=1
 647          * and generating UNIT_ATTENTIONs for ALUA access state transition.
 648          */
 649         transport_clear_lun_ref(lun);
 650
 651         mutex_lock(&tpg->tpg_lun_mutex);
 652         if (lun->lun_se_dev) {
 653                 target_detach_tg_pt_gp(lun);
 654
 655                 spin_lock(&dev->se_port_lock);
 656                 list_del(&lun->lun_dev_link);
 657                 dev->export_count--;
 658                 rcu_assign_pointer(lun->lun_se_dev, NULL);
 659                 spin_unlock(&dev->se_port_lock);
 660         }
 661         if (!(dev->se_hba->hba_flags & HBA_FLAGS_INTERNAL_USE))
 662                 hlist_del_rcu(&lun->link);
 663         mutex_unlock(&tpg->tpg_lun_mutex);
 664
 665         percpu_ref_exit(&lun->lun_ref);
 666 }