drivers/target/target_core_transport.c

   1 /*******************************************************************************
   2  * Filename:  target_core_transport.c
   3  *
   4  * This file contains the Generic Target Engine Core.
   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/delay.h>
  28 #include <linux/string.h>
  29 #include <linux/timer.h>
  30 #include <linux/slab.h>
  31 #include <linux/spinlock.h>
  32 #include <linux/kthread.h>
  33 #include <linux/in.h>
  34 #include <linux/cdrom.h>
  35 #include <linux/module.h>
  36 #include <linux/ratelimit.h>
  37 #include <linux/vmalloc.h>
  38 #include <asm/unaligned.h>
  39 #include <net/sock.h>
  40 #include <net/tcp.h>
  41 #include <scsi/scsi_proto.h>
  42 #include <scsi/scsi_common.h>
  43
  44 #include <target/target_core_base.h>
  45 #include <target/target_core_backend.h>
  46 #include <target/target_core_fabric.h>
  47
  48 #include "target_core_internal.h"
  49 #include "target_core_alua.h"
  50 #include "target_core_pr.h"
  51 #include "target_core_ua.h"
  52
  53 #define CREATE_TRACE_POINTS
  54 #include <trace/events/target.h>
  55
  56 static struct workqueue_struct *target_completion_wq;
  57 static struct kmem_cache *se_sess_cache;
  58 struct kmem_cache *se_ua_cache;
  59 struct kmem_cache *t10_pr_reg_cache;
  60 struct kmem_cache *t10_alua_lu_gp_cache;
  61 struct kmem_cache *t10_alua_lu_gp_mem_cache;
  62 struct kmem_cache *t10_alua_tg_pt_gp_cache;
  63 struct kmem_cache *t10_alua_lba_map_cache;
  64 struct kmem_cache *t10_alua_lba_map_mem_cache;
  65
  66 static void transport_complete_task_attr(struct se_cmd *cmd);
  67 static void transport_handle_queue_full(struct se_cmd *cmd,
  68                 struct se_device *dev);
  69 static int transport_put_cmd(struct se_cmd *cmd);
  70 static void target_complete_ok_work(struct work_struct *work);
  71
  72 int init_se_kmem_caches(void)
  73 {
  74         se_sess_cache = kmem_cache_create("se_sess_cache",
  75                         sizeof(struct se_session), __alignof__(struct se_session),
  76                         0, NULL);
  77         if (!se_sess_cache) {
  78                 pr_err("kmem_cache_create() for struct se_session"
  79                                 " failed\n");
  80                 goto out;
  81         }
  82         se_ua_cache = kmem_cache_create("se_ua_cache",
  83                         sizeof(struct se_ua), __alignof__(struct se_ua),
  84                         0, NULL);
  85         if (!se_ua_cache) {
  86                 pr_err("kmem_cache_create() for struct se_ua failed\n");
  87                 goto out_free_sess_cache;
  88         }
  89         t10_pr_reg_cache = kmem_cache_create("t10_pr_reg_cache",
  90                         sizeof(struct t10_pr_registration),
  91                         __alignof__(struct t10_pr_registration), 0, NULL);
  92         if (!t10_pr_reg_cache) {
  93                 pr_err("kmem_cache_create() for struct t10_pr_registration"
  94                                 " failed\n");
  95                 goto out_free_ua_cache;
  96         }
  97         t10_alua_lu_gp_cache = kmem_cache_create("t10_alua_lu_gp_cache",
  98                         sizeof(struct t10_alua_lu_gp), __alignof__(struct t10_alua_lu_gp),
  99                         0, NULL);
 100         if (!t10_alua_lu_gp_cache) {
 101                 pr_err("kmem_cache_create() for t10_alua_lu_gp_cache"
 102                                 " failed\n");
 103                 goto out_free_pr_reg_cache;
 104         }
 105         t10_alua_lu_gp_mem_cache = kmem_cache_create("t10_alua_lu_gp_mem_cache",
 106                         sizeof(struct t10_alua_lu_gp_member),
 107                         __alignof__(struct t10_alua_lu_gp_member), 0, NULL);
 108         if (!t10_alua_lu_gp_mem_cache) {
 109                 pr_err("kmem_cache_create() for t10_alua_lu_gp_mem_"
 110                                 "cache failed\n");
 111                 goto out_free_lu_gp_cache;
 112         }
 113         t10_alua_tg_pt_gp_cache = kmem_cache_create("t10_alua_tg_pt_gp_cache",
 114                         sizeof(struct t10_alua_tg_pt_gp),
 115                         __alignof__(struct t10_alua_tg_pt_gp), 0, NULL);
 116         if (!t10_alua_tg_pt_gp_cache) {
 117                 pr_err("kmem_cache_create() for t10_alua_tg_pt_gp_"
 118                                 "cache failed\n");
 119                 goto out_free_lu_gp_mem_cache;
 120         }
 121         t10_alua_lba_map_cache = kmem_cache_create(
 122                         "t10_alua_lba_map_cache",
 123                         sizeof(struct t10_alua_lba_map),
 124                         __alignof__(struct t10_alua_lba_map), 0, NULL);
 125         if (!t10_alua_lba_map_cache) {
 126                 pr_err("kmem_cache_create() for t10_alua_lba_map_"
 127                                 "cache failed\n");
 128                 goto out_free_tg_pt_gp_cache;
 129         }
 130         t10_alua_lba_map_mem_cache = kmem_cache_create(
 131                         "t10_alua_lba_map_mem_cache",
 132                         sizeof(struct t10_alua_lba_map_member),
 133                         __alignof__(struct t10_alua_lba_map_member), 0, NULL);
 134         if (!t10_alua_lba_map_mem_cache) {
 135                 pr_err("kmem_cache_create() for t10_alua_lba_map_mem_"
 136                                 "cache failed\n");
 137                 goto out_free_lba_map_cache;
 138         }
 139
 140         target_completion_wq = alloc_workqueue("target_completion",
 141                                                WQ_MEM_RECLAIM, 0);
 142         if (!target_completion_wq)
 143                 goto out_free_lba_map_mem_cache;
 144
 145         return 0;
 146
 147 out_free_lba_map_mem_cache:
 148         kmem_cache_destroy(t10_alua_lba_map_mem_cache);
 149 out_free_lba_map_cache:
 150         kmem_cache_destroy(t10_alua_lba_map_cache);
 151 out_free_tg_pt_gp_cache:
 152         kmem_cache_destroy(t10_alua_tg_pt_gp_cache);
 153 out_free_lu_gp_mem_cache:
 154         kmem_cache_destroy(t10_alua_lu_gp_mem_cache);
 155 out_free_lu_gp_cache:
 156         kmem_cache_destroy(t10_alua_lu_gp_cache);
 157 out_free_pr_reg_cache:
 158         kmem_cache_destroy(t10_pr_reg_cache);
 159 out_free_ua_cache:
 160         kmem_cache_destroy(se_ua_cache);
 161 out_free_sess_cache:
 162         kmem_cache_destroy(se_sess_cache);
 163 out:
 164         return -ENOMEM;
 165 }
 166
 167 void release_se_kmem_caches(void)
 168 {
 169         destroy_workqueue(target_completion_wq);
 170         kmem_cache_destroy(se_sess_cache);
 171         kmem_cache_destroy(se_ua_cache);
 172         kmem_cache_destroy(t10_pr_reg_cache);
 173         kmem_cache_destroy(t10_alua_lu_gp_cache);
 174         kmem_cache_destroy(t10_alua_lu_gp_mem_cache);
 175         kmem_cache_destroy(t10_alua_tg_pt_gp_cache);
 176         kmem_cache_destroy(t10_alua_lba_map_cache);
 177         kmem_cache_destroy(t10_alua_lba_map_mem_cache);
 178 }
 179
 180 /* This code ensures unique mib indexes are handed out. */
 181 static DEFINE_SPINLOCK(scsi_mib_index_lock);
 182 static u32 scsi_mib_index[SCSI_INDEX_TYPE_MAX];
 183
 184 /*
 185  * Allocate a new row index for the entry type specified
 186  */
 187 u32 scsi_get_new_index(scsi_index_t type)
 188 {
 189         u32 new_index;
 190
 191         BUG_ON((type < 0) || (type >= SCSI_INDEX_TYPE_MAX));
 192
 193         spin_lock(&scsi_mib_index_lock);
 194         new_index = ++scsi_mib_index[type];
 195         spin_unlock(&scsi_mib_index_lock);
 196
 197         return new_index;
 198 }
 199
 200 void transport_subsystem_check_init(void)
 201 {
 202         int ret;
 203         static int sub_api_initialized;
 204
 205         if (sub_api_initialized)
 206                 return;
 207
 208         ret = request_module("target_core_iblock");
 209         if (ret != 0)
 210                 pr_err("Unable to load target_core_iblock\n");
 211
 212         ret = request_module("target_core_file");
 213         if (ret != 0)
 214                 pr_err("Unable to load target_core_file\n");
 215
 216         ret = request_module("target_core_pscsi");
 217         if (ret != 0)
 218                 pr_err("Unable to load target_core_pscsi\n");
 219
 220         ret = request_module("target_core_user");
 221         if (ret != 0)
 222                 pr_err("Unable to load target_core_user\n");
 223
 224         sub_api_initialized = 1;
 225 }
 226
 227 struct se_session *transport_init_session(enum target_prot_op sup_prot_ops)
 228 {
 229         struct se_session *se_sess;
 230
 231         se_sess = kmem_cache_zalloc(se_sess_cache, GFP_KERNEL);
 232         if (!se_sess) {
 233                 pr_err("Unable to allocate struct se_session from"
 234                                 " se_sess_cache\n");
 235                 return ERR_PTR(-ENOMEM);
 236         }
 237         INIT_LIST_HEAD(&se_sess->sess_list);
 238         INIT_LIST_HEAD(&se_sess->sess_acl_list);
 239         INIT_LIST_HEAD(&se_sess->sess_cmd_list);
 240         INIT_LIST_HEAD(&se_sess->sess_wait_list);
 241         spin_lock_init(&se_sess->sess_cmd_lock);
 242         kref_init(&se_sess->sess_kref);
 243         se_sess->sup_prot_ops = sup_prot_ops;
 244
 245         return se_sess;
 246 }
 247 EXPORT_SYMBOL(transport_init_session);
 248
 249 int transport_alloc_session_tags(struct se_session *se_sess,
 250                                  unsigned int tag_num, unsigned int tag_size)
 251 {
 252         int rc;
 253
 254         se_sess->sess_cmd_map = kzalloc(tag_num * tag_size,
 255                                         GFP_KERNEL | __GFP_NOWARN | __GFP_REPEAT);
 256         if (!se_sess->sess_cmd_map) {
 257                 se_sess->sess_cmd_map = vzalloc(tag_num * tag_size);
 258                 if (!se_sess->sess_cmd_map) {
 259                         pr_err("Unable to allocate se_sess->sess_cmd_map\n");
 260                         return -ENOMEM;
 261                 }
 262         }
 263
 264         rc = percpu_ida_init(&se_sess->sess_tag_pool, tag_num);
 265         if (rc < 0) {
 266                 pr_err("Unable to init se_sess->sess_tag_pool,"
 267                         " tag_num: %u\n", tag_num);
 268                 kvfree(se_sess->sess_cmd_map);
 269                 se_sess->sess_cmd_map = NULL;
 270                 return -ENOMEM;
 271         }
 272
 273         return 0;
 274 }
 275 EXPORT_SYMBOL(transport_alloc_session_tags);
 276
 277 struct se_session *transport_init_session_tags(unsigned int tag_num,
 278                                                unsigned int tag_size,
 279                                                enum target_prot_op sup_prot_ops)
 280 {
 281         struct se_session *se_sess;
 282         int rc;
 283
 284         se_sess = transport_init_session(sup_prot_ops);
 285         if (IS_ERR(se_sess))
 286                 return se_sess;
 287
 288         rc = transport_alloc_session_tags(se_sess, tag_num, tag_size);
 289         if (rc < 0) {
 290                 transport_free_session(se_sess);
 291                 return ERR_PTR(-ENOMEM);
 292         }
 293
 294         return se_sess;
 295 }
 296 EXPORT_SYMBOL(transport_init_session_tags);
 297
 298 /*
 299  * Called with spin_lock_irqsave(&struct se_portal_group->session_lock called.
 300  */
 301 void __transport_register_session(
 302         struct se_portal_group *se_tpg,
 303         struct se_node_acl *se_nacl,
 304         struct se_session *se_sess,
 305         void *fabric_sess_ptr)
 306 {
 307         const struct target_core_fabric_ops *tfo = se_tpg->se_tpg_tfo;
 308         unsigned char buf[PR_REG_ISID_LEN];
 309
 310         se_sess->se_tpg = se_tpg;
 311         se_sess->fabric_sess_ptr = fabric_sess_ptr;
 312         /*
 313          * Used by struct se_node_acl's under ConfigFS to locate active se_session-t
 314          *
 315          * Only set for struct se_session's that will actually be moving I/O.
 316          * eg: *NOT* discovery sessions.
 317          */
 318         if (se_nacl) {
 319                 /*
 320                  *
 321                  * Determine if fabric allows for T10-PI feature bits exposed to
 322                  * initiators for device backends with !dev->dev_attrib.pi_prot_type.
 323                  *
 324                  * If so, then always save prot_type on a per se_node_acl node
 325                  * basis and re-instate the previous sess_prot_type to avoid
 326                  * disabling PI from below any previously initiator side
 327                  * registered LUNs.
 328                  */
 329                 if (se_nacl->saved_prot_type)
 330                         se_sess->sess_prot_type = se_nacl->saved_prot_type;
 331                 else if (tfo->tpg_check_prot_fabric_only)
 332                         se_sess->sess_prot_type = se_nacl->saved_prot_type =
 333                                         tfo->tpg_check_prot_fabric_only(se_tpg);
 334                 /*
 335                  * If the fabric module supports an ISID based TransportID,
 336                  * save this value in binary from the fabric I_T Nexus now.
 337                  */
 338                 if (se_tpg->se_tpg_tfo->sess_get_initiator_sid != NULL) {
 339                         memset(&buf[0], 0, PR_REG_ISID_LEN);
 340                         se_tpg->se_tpg_tfo->sess_get_initiator_sid(se_sess,
 341                                         &buf[0], PR_REG_ISID_LEN);
 342                         se_sess->sess_bin_isid = get_unaligned_be64(&buf[0]);
 343                 }
 344                 kref_get(&se_nacl->acl_kref);
 345
 346                 spin_lock_irq(&se_nacl->nacl_sess_lock);
 347                 /*
 348                  * The se_nacl->nacl_sess pointer will be set to the
 349                  * last active I_T Nexus for each struct se_node_acl.
 350                  */
 351                 se_nacl->nacl_sess = se_sess;
 352
 353                 list_add_tail(&se_sess->sess_acl_list,
 354                               &se_nacl->acl_sess_list);
 355                 spin_unlock_irq(&se_nacl->nacl_sess_lock);
 356         }
 357         list_add_tail(&se_sess->sess_list, &se_tpg->tpg_sess_list);
 358
 359         pr_debug("TARGET_CORE[%s]: Registered fabric_sess_ptr: %p\n",
 360                 se_tpg->se_tpg_tfo->get_fabric_name(), se_sess->fabric_sess_ptr);
 361 }
 362 EXPORT_SYMBOL(__transport_register_session);
 363
 364 void transport_register_session(
 365         struct se_portal_group *se_tpg,
 366         struct se_node_acl *se_nacl,
 367         struct se_session *se_sess,
 368         void *fabric_sess_ptr)
 369 {
 370         unsigned long flags;
 371
 372         spin_lock_irqsave(&se_tpg->session_lock, flags);
 373         __transport_register_session(se_tpg, se_nacl, se_sess, fabric_sess_ptr);
 374         spin_unlock_irqrestore(&se_tpg->session_lock, flags);
 375 }
 376 EXPORT_SYMBOL(transport_register_session);
 377
 378 static void target_release_session(struct kref *kref)
 379 {
 380         struct se_session *se_sess = container_of(kref,
 381                         struct se_session, sess_kref);
 382         struct se_portal_group *se_tpg = se_sess->se_tpg;
 383
 384         se_tpg->se_tpg_tfo->close_session(se_sess);
 385 }
 386
 387 void target_get_session(struct se_session *se_sess)
 388 {
 389         kref_get(&se_sess->sess_kref);
 390 }
 391 EXPORT_SYMBOL(target_get_session);
 392
 393 void target_put_session(struct se_session *se_sess)
 394 {
 395         kref_put(&se_sess->sess_kref, target_release_session);
 396 }
 397 EXPORT_SYMBOL(target_put_session);
 398
 399 ssize_t target_show_dynamic_sessions(struct se_portal_group *se_tpg, char *page)
 400 {
 401         struct se_session *se_sess;
 402         ssize_t len = 0;
 403
 404         spin_lock_bh(&se_tpg->session_lock);
 405         list_for_each_entry(se_sess, &se_tpg->tpg_sess_list, sess_list) {
 406                 if (!se_sess->se_node_acl)
 407                         continue;
 408                 if (!se_sess->se_node_acl->dynamic_node_acl)
 409                         continue;
 410                 if (strlen(se_sess->se_node_acl->initiatorname) + 1 + len > PAGE_SIZE)
 411                         break;
 412
 413                 len += snprintf(page + len, PAGE_SIZE - len, "%s\n",
 414                                 se_sess->se_node_acl->initiatorname);
 415                 len += 1; /* Include NULL terminator */
 416         }
 417         spin_unlock_bh(&se_tpg->session_lock);
 418
 419         return len;
 420 }
 421 EXPORT_SYMBOL(target_show_dynamic_sessions);
 422
 423 static void target_complete_nacl(struct kref *kref)
 424 {
 425         struct se_node_acl *nacl = container_of(kref,
 426                                 struct se_node_acl, acl_kref);
 427
 428         complete(&nacl->acl_free_comp);
 429 }
 430
 431 void target_put_nacl(struct se_node_acl *nacl)
 432 {
 433         kref_put(&nacl->acl_kref, target_complete_nacl);
 434 }
 435
 436 void transport_deregister_session_configfs(struct se_session *se_sess)
 437 {
 438         struct se_node_acl *se_nacl;
 439         unsigned long flags;
 440         /*
 441          * Used by struct se_node_acl's under ConfigFS to locate active struct se_session
 442          */
 443         se_nacl = se_sess->se_node_acl;
 444         if (se_nacl) {
 445                 spin_lock_irqsave(&se_nacl->nacl_sess_lock, flags);
 446                 if (se_nacl->acl_stop == 0)
 447                         list_del(&se_sess->sess_acl_list);
 448                 /*
 449                  * If the session list is empty, then clear the pointer.
 450                  * Otherwise, set the struct se_session pointer from the tail
 451                  * element of the per struct se_node_acl active session list.
 452                  */
 453                 if (list_empty(&se_nacl->acl_sess_list))
 454                         se_nacl->nacl_sess = NULL;
 455                 else {
 456                         se_nacl->nacl_sess = container_of(
 457                                         se_nacl->acl_sess_list.prev,
 458                                         struct se_session, sess_acl_list);
 459                 }
 460                 spin_unlock_irqrestore(&se_nacl->nacl_sess_lock, flags);
 461         }
 462 }
 463 EXPORT_SYMBOL(transport_deregister_session_configfs);
 464
 465 void transport_free_session(struct se_session *se_sess)
 466 {
 467         if (se_sess->sess_cmd_map) {
 468                 percpu_ida_destroy(&se_sess->sess_tag_pool);
 469                 kvfree(se_sess->sess_cmd_map);
 470         }
 471         kmem_cache_free(se_sess_cache, se_sess);
 472 }
 473 EXPORT_SYMBOL(transport_free_session);
 474
 475 void transport_deregister_session(struct se_session *se_sess)
 476 {
 477         struct se_portal_group *se_tpg = se_sess->se_tpg;
 478         const struct target_core_fabric_ops *se_tfo;
 479         struct se_node_acl *se_nacl;
 480         unsigned long flags;
 481         bool comp_nacl = true, drop_nacl = false;
 482
 483         if (!se_tpg) {
 484                 transport_free_session(se_sess);
 485                 return;
 486         }
 487         se_tfo = se_tpg->se_tpg_tfo;
 488
 489         spin_lock_irqsave(&se_tpg->session_lock, flags);
 490         list_del(&se_sess->sess_list);
 491         se_sess->se_tpg = NULL;
 492         se_sess->fabric_sess_ptr = NULL;
 493         spin_unlock_irqrestore(&se_tpg->session_lock, flags);
 494
 495         /*
 496          * Determine if we need to do extra work for this initiator node's
 497          * struct se_node_acl if it had been previously dynamically generated.
 498          */
 499         se_nacl = se_sess->se_node_acl;
 500
 501         mutex_lock(&se_tpg->acl_node_mutex);
 502         if (se_nacl && se_nacl->dynamic_node_acl) {
 503                 if (!se_tfo->tpg_check_demo_mode_cache(se_tpg)) {
 504                         list_del(&se_nacl->acl_list);
 505                         se_tpg->num_node_acls--;
 506                         drop_nacl = true;
 507                 }
 508         }
 509         mutex_unlock(&se_tpg->acl_node_mutex);
 510
 511         if (drop_nacl) {
 512                 core_tpg_wait_for_nacl_pr_ref(se_nacl);
 513                 core_free_device_list_for_node(se_nacl, se_tpg);
 514                 kfree(se_nacl);
 515                 comp_nacl = false;
 516         }
 517         pr_debug("TARGET_CORE[%s]: Deregistered fabric_sess\n",
 518                 se_tpg->se_tpg_tfo->get_fabric_name());
 519         /*
 520          * If last kref is dropping now for an explicit NodeACL, awake sleeping
 521          * ->acl_free_comp caller to wakeup configfs se_node_acl->acl_group
 522          * removal context.
 523          */
 524         if (se_nacl && comp_nacl)
 525                 target_put_nacl(se_nacl);
 526
 527         transport_free_session(se_sess);
 528 }
 529 EXPORT_SYMBOL(transport_deregister_session);
 530
 531 /*
 532  * Called with cmd->t_state_lock held.
 533  */
 534 static void target_remove_from_state_list(struct se_cmd *cmd)
 535 {
 536         struct se_device *dev = cmd->se_dev;
 537         unsigned long flags;
 538
 539         if (!dev)
 540                 return;
 541
 542         if (cmd->transport_state & CMD_T_BUSY)
 543                 return;
 544
 545         spin_lock_irqsave(&dev->execute_task_lock, flags);
 546         if (cmd->state_active) {
 547                 list_del(&cmd->state_list);
 548                 cmd->state_active = false;
 549         }
 550         spin_unlock_irqrestore(&dev->execute_task_lock, flags);
 551 }
 552
 553 static int transport_cmd_check_stop(struct se_cmd *cmd, bool remove_from_lists,
 554                                     bool write_pending)
 555 {
 556         unsigned long flags;
 557
 558         spin_lock_irqsave(&cmd->t_state_lock, flags);
 559         if (write_pending)
 560                 cmd->t_state = TRANSPORT_WRITE_PENDING;
 561
 562         if (remove_from_lists) {
 563                 target_remove_from_state_list(cmd);
 564
 565                 /*
 566                  * Clear struct se_cmd->se_lun before the handoff to FE.
 567                  */
 568                 cmd->se_lun = NULL;
 569         }
 570
 571         /*
 572          * Determine if frontend context caller is requesting the stopping of
 573          * this command for frontend exceptions.
 574          */
 575         if (cmd->transport_state & CMD_T_STOP) {
 576                 pr_debug("%s:%d CMD_T_STOP for ITT: 0x%08llx\n",
 577                         __func__, __LINE__, cmd->tag);
 578
 579                 spin_unlock_irqrestore(&cmd->t_state_lock, flags);
 580
 581                 complete_all(&cmd->t_transport_stop_comp);
 582                 return 1;
 583         }
 584
 585         cmd->transport_state &= ~CMD_T_ACTIVE;
 586         if (remove_from_lists) {
 587                 /*
 588                  * Some fabric modules like tcm_loop can release
 589                  * their internally allocated I/O reference now and
 590                  * struct se_cmd now.
 591                  *
 592                  * Fabric modules are expected to return '1' here if the
 593                  * se_cmd being passed is released at this point,
 594                  * or zero if not being released.
 595                  */
 596                 if (cmd->se_tfo->check_stop_free != NULL) {
 597                         spin_unlock_irqrestore(&cmd->t_state_lock, flags);
 598                         return cmd->se_tfo->check_stop_free(cmd);
 599                 }
 600         }
 601
 602         spin_unlock_irqrestore(&cmd->t_state_lock, flags);
 603         return 0;
 604 }
 605
 606 static int transport_cmd_check_stop_to_fabric(struct se_cmd *cmd)
 607 {
 608         return transport_cmd_check_stop(cmd, true, false);
 609 }
 610
 611 static void transport_lun_remove_cmd(struct se_cmd *cmd)
 612 {
 613         struct se_lun *lun = cmd->se_lun;
 614
 615         if (!lun)
 616                 return;
 617
 618         if (cmpxchg(&cmd->lun_ref_active, true, false))
 619                 percpu_ref_put(&lun->lun_ref);
 620 }
 621
 622 void transport_cmd_finish_abort(struct se_cmd *cmd, int remove)
 623 {
 624         if (cmd->se_cmd_flags & SCF_SE_LUN_CMD)
 625                 transport_lun_remove_cmd(cmd);
 626         /*
 627          * Allow the fabric driver to unmap any resources before
 628          * releasing the descriptor via TFO->release_cmd()
 629          */
 630         if (remove)
 631                 cmd->se_tfo->aborted_task(cmd);
 632
 633         if (transport_cmd_check_stop_to_fabric(cmd))
 634                 return;
 635         if (remove)
 636                 transport_put_cmd(cmd);
 637 }
 638
 639 static void target_complete_failure_work(struct work_struct *work)
 640 {
 641         struct se_cmd *cmd = container_of(work, struct se_cmd, work);
 642
 643         transport_generic_request_failure(cmd,
 644                         TCM_LOGICAL_UNIT_COMMUNICATION_FAILURE);
 645 }
 646
 647 /*
 648  * Used when asking transport to copy Sense Data from the underlying
 649  * Linux/SCSI struct scsi_cmnd
 650  */
 651 static unsigned char *transport_get_sense_buffer(struct se_cmd *cmd)
 652 {
 653         struct se_device *dev = cmd->se_dev;
 654
 655         WARN_ON(!cmd->se_lun);
 656
 657         if (!dev)
 658                 return NULL;
 659
 660         if (cmd->se_cmd_flags & SCF_SENT_CHECK_CONDITION)
 661                 return NULL;
 662
 663         cmd->scsi_sense_length = TRANSPORT_SENSE_BUFFER;
 664
 665         pr_debug("HBA_[%u]_PLUG[%s]: Requesting sense for SAM STATUS: 0x%02x\n",
 666                 dev->se_hba->hba_id, dev->transport->name, cmd->scsi_status);
 667         return cmd->sense_buffer;
 668 }
 669
 670 void target_complete_cmd(struct se_cmd *cmd, u8 scsi_status)
 671 {
 672         struct se_device *dev = cmd->se_dev;
 673         int success = scsi_status == GOOD;
 674         unsigned long flags;
 675
 676         cmd->scsi_status = scsi_status;
 677
 678
 679         spin_lock_irqsave(&cmd->t_state_lock, flags);
 680         cmd->transport_state &= ~CMD_T_BUSY;
 681
 682         if (dev && dev->transport->transport_complete) {
 683                 dev->transport->transport_complete(cmd,
 684                                 cmd->t_data_sg,
 685                                 transport_get_sense_buffer(cmd));
 686                 if (cmd->se_cmd_flags & SCF_TRANSPORT_TASK_SENSE)
 687                         success = 1;
 688         }
 689
 690         /*
 691          * See if we are waiting to complete for an exception condition.
 692          */
 693         if (cmd->transport_state & CMD_T_REQUEST_STOP) {
 694                 spin_unlock_irqrestore(&cmd->t_state_lock, flags);
 695                 complete(&cmd->task_stop_comp);
 696                 return;
 697         }
 698
 699         /*
 700          * Check for case where an explicit ABORT_TASK has been received
 701          * and transport_wait_for_tasks() will be waiting for completion..
 702          */
 703         if (cmd->transport_state & CMD_T_ABORTED &&
 704             cmd->transport_state & CMD_T_STOP) {
 705                 spin_unlock_irqrestore(&cmd->t_state_lock, flags);
 706                 complete_all(&cmd->t_transport_stop_comp);
 707                 return;
 708         } else if (!success) {
 709                 INIT_WORK(&cmd->work, target_complete_failure_work);
 710         } else {
 711                 INIT_WORK(&cmd->work, target_complete_ok_work);
 712         }
 713
 714         cmd->t_state = TRANSPORT_COMPLETE;
 715         cmd->transport_state |= (CMD_T_COMPLETE | CMD_T_ACTIVE);
 716         spin_unlock_irqrestore(&cmd->t_state_lock, flags);
 717
 718         queue_work(target_completion_wq, &cmd->work);
 719 }
 720 EXPORT_SYMBOL(target_complete_cmd);
 721
 722 void target_complete_cmd_with_length(struct se_cmd *cmd, u8 scsi_status, int length)
 723 {
 724         if (scsi_status == SAM_STAT_GOOD && length < cmd->data_length) {
 725                 if (cmd->se_cmd_flags & SCF_UNDERFLOW_BIT) {
 726                         cmd->residual_count += cmd->data_length - length;
 727                 } else {
 728                         cmd->se_cmd_flags |= SCF_UNDERFLOW_BIT;
 729                         cmd->residual_count = cmd->data_length - length;
 730                 }
 731
 732                 cmd->data_length = length;
 733         }
 734
 735         target_complete_cmd(cmd, scsi_status);
 736 }
 737 EXPORT_SYMBOL(target_complete_cmd_with_length);
 738
 739 static void target_add_to_state_list(struct se_cmd *cmd)
 740 {
 741         struct se_device *dev = cmd->se_dev;
 742         unsigned long flags;
 743
 744         spin_lock_irqsave(&dev->execute_task_lock, flags);
 745         if (!cmd->state_active) {
 746                 list_add_tail(&cmd->state_list, &dev->state_list);
 747                 cmd->state_active = true;
 748         }
 749         spin_unlock_irqrestore(&dev->execute_task_lock, flags);
 750 }
 751
 752 /*
 753  * Handle QUEUE_FULL / -EAGAIN and -ENOMEM status
 754  */
 755 static void transport_write_pending_qf(struct se_cmd *cmd);
 756 static void transport_complete_qf(struct se_cmd *cmd);
 757
 758 void target_qf_do_work(struct work_struct *work)
 759 {
 760         struct se_device *dev = container_of(work, struct se_device,
 761                                         qf_work_queue);
 762         LIST_HEAD(qf_cmd_list);
 763         struct se_cmd *cmd, *cmd_tmp;
 764
 765         spin_lock_irq(&dev->qf_cmd_lock);
 766         list_splice_init(&dev->qf_cmd_list, &qf_cmd_list);
 767         spin_unlock_irq(&dev->qf_cmd_lock);
 768
 769         list_for_each_entry_safe(cmd, cmd_tmp, &qf_cmd_list, se_qf_node) {
 770                 list_del(&cmd->se_qf_node);
 771                 atomic_dec_mb(&dev->dev_qf_count);
 772
 773                 pr_debug("Processing %s cmd: %p QUEUE_FULL in work queue"
 774                         " context: %s\n", cmd->se_tfo->get_fabric_name(), cmd,
 775                         (cmd->t_state == TRANSPORT_COMPLETE_QF_OK) ? "COMPLETE_OK" :
 776                         (cmd->t_state == TRANSPORT_COMPLETE_QF_WP) ? "WRITE_PENDING"
 777                         : "UNKNOWN");
 778
 779                 if (cmd->t_state == TRANSPORT_COMPLETE_QF_WP)
 780                         transport_write_pending_qf(cmd);
 781                 else if (cmd->t_state == TRANSPORT_COMPLETE_QF_OK)
 782                         transport_complete_qf(cmd);
 783         }
 784 }
 785
 786 unsigned char *transport_dump_cmd_direction(struct se_cmd *cmd)
 787 {
 788         switch (cmd->data_direction) {
 789         case DMA_NONE:
 790                 return "NONE";
 791         case DMA_FROM_DEVICE:
 792                 return "READ";
 793         case DMA_TO_DEVICE:
 794                 return "WRITE";
 795         case DMA_BIDIRECTIONAL:
 796                 return "BIDI";
 797         default:
 798                 break;
 799         }
 800
 801         return "UNKNOWN";
 802 }
 803
 804 void transport_dump_dev_state(
 805         struct se_device *dev,
 806         char *b,
 807         int *bl)
 808 {
 809         *bl += sprintf(b + *bl, "Status: ");
 810         if (dev->export_count)
 811                 *bl += sprintf(b + *bl, "ACTIVATED");
 812         else
 813                 *bl += sprintf(b + *bl, "DEACTIVATED");
 814
 815         *bl += sprintf(b + *bl, "  Max Queue Depth: %d", dev->queue_depth);
 816         *bl += sprintf(b + *bl, "  SectorSize: %u  HwMaxSectors: %u\n",
 817                 dev->dev_attrib.block_size,
 818                 dev->dev_attrib.hw_max_sectors);
 819         *bl += sprintf(b + *bl, "        ");
 820 }
 821
 822 void transport_dump_vpd_proto_id(
 823         struct t10_vpd *vpd,
 824         unsigned char *p_buf,
 825         int p_buf_len)
 826 {
 827         unsigned char buf[VPD_TMP_BUF_SIZE];
 828         int len;
 829
 830         memset(buf, 0, VPD_TMP_BUF_SIZE);
 831         len = sprintf(buf, "T10 VPD Protocol Identifier: ");
 832
 833         switch (vpd->protocol_identifier) {
 834         case 0x00:
 835                 sprintf(buf+len, "Fibre Channel\n");
 836                 break;
 837         case 0x10:
 838                 sprintf(buf+len, "Parallel SCSI\n");
 839                 break;
 840         case 0x20:
 841                 sprintf(buf+len, "SSA\n");
 842                 break;
 843         case 0x30:
 844                 sprintf(buf+len, "IEEE 1394\n");
 845                 break;
 846         case 0x40:
 847                 sprintf(buf+len, "SCSI Remote Direct Memory Access"
 848                                 " Protocol\n");
 849                 break;
 850         case 0x50:
 851                 sprintf(buf+len, "Internet SCSI (iSCSI)\n");
 852                 break;
 853         case 0x60:
 854                 sprintf(buf+len, "SAS Serial SCSI Protocol\n");
 855                 break;
 856         case 0x70:
 857                 sprintf(buf+len, "Automation/Drive Interface Transport"
 858                                 " Protocol\n");
 859                 break;
 860         case 0x80:
 861                 sprintf(buf+len, "AT Attachment Interface ATA/ATAPI\n");
 862                 break;
 863         default:
 864                 sprintf(buf+len, "Unknown 0x%02x\n",
 865                                 vpd->protocol_identifier);
 866                 break;
 867         }
 868
 869         if (p_buf)
 870                 strncpy(p_buf, buf, p_buf_len);
 871         else
 872                 pr_debug("%s", buf);
 873 }
 874
 875 void
 876 transport_set_vpd_proto_id(struct t10_vpd *vpd, unsigned char *page_83)
 877 {
 878         /*
 879          * Check if the Protocol Identifier Valid (PIV) bit is set..
 880          *
 881          * from spc3r23.pdf section 7.5.1
 882          */
 883          if (page_83[1] & 0x80) {
 884                 vpd->protocol_identifier = (page_83[0] & 0xf0);
 885                 vpd->protocol_identifier_set = 1;
 886                 transport_dump_vpd_proto_id(vpd, NULL, 0);
 887         }
 888 }
 889 EXPORT_SYMBOL(transport_set_vpd_proto_id);
 890
 891 int transport_dump_vpd_assoc(
 892         struct t10_vpd *vpd,
 893         unsigned char *p_buf,
 894         int p_buf_len)
 895 {
 896         unsigned char buf[VPD_TMP_BUF_SIZE];
 897         int ret = 0;
 898         int len;
 899
 900         memset(buf, 0, VPD_TMP_BUF_SIZE);
 901         len = sprintf(buf, "T10 VPD Identifier Association: ");
 902
 903         switch (vpd->association) {
 904         case 0x00:
 905                 sprintf(buf+len, "addressed logical unit\n");
 906                 break;
 907         case 0x10:
 908                 sprintf(buf+len, "target port\n");
 909                 break;
 910         case 0x20:
 911                 sprintf(buf+len, "SCSI target device\n");
 912                 break;
 913         default:
 914                 sprintf(buf+len, "Unknown 0x%02x\n", vpd->association);
 915                 ret = -EINVAL;
 916                 break;
 917         }
 918
 919         if (p_buf)
 920                 strncpy(p_buf, buf, p_buf_len);
 921         else
 922                 pr_debug("%s", buf);
 923
 924         return ret;
 925 }
 926
 927 int transport_set_vpd_assoc(struct t10_vpd *vpd, unsigned char *page_83)
 928 {
 929         /*
 930          * The VPD identification association..
 931          *
 932          * from spc3r23.pdf Section 7.6.3.1 Table 297
 933          */
 934         vpd->association = (page_83[1] & 0x30);
 935         return transport_dump_vpd_assoc(vpd, NULL, 0);
 936 }
 937 EXPORT_SYMBOL(transport_set_vpd_assoc);
 938
 939 int transport_dump_vpd_ident_type(
 940         struct t10_vpd *vpd,
 941         unsigned char *p_buf,
 942         int p_buf_len)
 943 {
 944         unsigned char buf[VPD_TMP_BUF_SIZE];
 945         int ret = 0;
 946         int len;
 947
 948         memset(buf, 0, VPD_TMP_BUF_SIZE);
 949         len = sprintf(buf, "T10 VPD Identifier Type: ");
 950
 951         switch (vpd->device_identifier_type) {
 952         case 0x00:
 953                 sprintf(buf+len, "Vendor specific\n");
 954                 break;
 955         case 0x01:
 956                 sprintf(buf+len, "T10 Vendor ID based\n");
 957                 break;
 958         case 0x02:
 959                 sprintf(buf+len, "EUI-64 based\n");
 960                 break;
 961         case 0x03:
 962                 sprintf(buf+len, "NAA\n");
 963                 break;
 964         case 0x04:
 965                 sprintf(buf+len, "Relative target port identifier\n");
 966                 break;
 967         case 0x08:
 968                 sprintf(buf+len, "SCSI name string\n");
 969                 break;
 970         default:
 971                 sprintf(buf+len, "Unsupported: 0x%02x\n",
 972                                 vpd->device_identifier_type);
 973                 ret = -EINVAL;
 974                 break;
 975         }
 976
 977         if (p_buf) {
 978                 if (p_buf_len < strlen(buf)+1)
 979                         return -EINVAL;
 980                 strncpy(p_buf, buf, p_buf_len);
 981         } else {
 982                 pr_debug("%s", buf);
 983         }
 984
 985         return ret;
 986 }
 987
 988 int transport_set_vpd_ident_type(struct t10_vpd *vpd, unsigned char *page_83)
 989 {
 990         /*
 991          * The VPD identifier type..
 992          *
 993          * from spc3r23.pdf Section 7.6.3.1 Table 298
 994          */
 995         vpd->device_identifier_type = (page_83[1] & 0x0f);
 996         return transport_dump_vpd_ident_type(vpd, NULL, 0);
 997 }
 998 EXPORT_SYMBOL(transport_set_vpd_ident_type);
 999
1000 int transport_dump_vpd_ident(
1001         struct t10_vpd *vpd,
1002         unsigned char *p_buf,
1003         int p_buf_len)
1004 {
1005         unsigned char buf[VPD_TMP_BUF_SIZE];
1006         int ret = 0;
1007
1008         memset(buf, 0, VPD_TMP_BUF_SIZE);
1009
1010         switch (vpd->device_identifier_code_set) {
1011         case 0x01: /* Binary */
1012                 snprintf(buf, sizeof(buf),
1013                         "T10 VPD Binary Device Identifier: %s\n",
1014                         &vpd->device_identifier[0]);
1015                 break;
1016         case 0x02: /* ASCII */
1017                 snprintf(buf, sizeof(buf),
1018                         "T10 VPD ASCII Device Identifier: %s\n",
1019                         &vpd->device_identifier[0]);
1020                 break;
1021         case 0x03: /* UTF-8 */
1022                 snprintf(buf, sizeof(buf),
1023                         "T10 VPD UTF-8 Device Identifier: %s\n",
1024                         &vpd->device_identifier[0]);
1025                 break;
1026         default:
1027                 sprintf(buf, "T10 VPD Device Identifier encoding unsupported:"
1028                         " 0x%02x", vpd->device_identifier_code_set);
1029                 ret = -EINVAL;
1030                 break;
1031         }
1032
1033         if (p_buf)
1034                 strncpy(p_buf, buf, p_buf_len);
1035         else
1036                 pr_debug("%s", buf);
1037
1038         return ret;
1039 }
1040
1041 int
1042 transport_set_vpd_ident(struct t10_vpd *vpd, unsigned char *page_83)
1043 {
1044         static const char hex_str[] = "0123456789abcdef";
1045         int j = 0, i = 4; /* offset to start of the identifier */
1046
1047         /*
1048          * The VPD Code Set (encoding)
1049          *
1050          * from spc3r23.pdf Section 7.6.3.1 Table 296
1051          */
1052         vpd->device_identifier_code_set = (page_83[0] & 0x0f);
1053         switch (vpd->device_identifier_code_set) {
1054         case 0x01: /* Binary */
1055                 vpd->device_identifier[j++] =
1056                                 hex_str[vpd->device_identifier_type];
1057                 while (i < (4 + page_83[3])) {
1058                         vpd->device_identifier[j++] =
1059                                 hex_str[(page_83[i] & 0xf0) >> 4];
1060                         vpd->device_identifier[j++] =
1061                                 hex_str[page_83[i] & 0x0f];
1062                         i++;
1063                 }
1064                 break;
1065         case 0x02: /* ASCII */
1066         case 0x03: /* UTF-8 */
1067                 while (i < (4 + page_83[3]))
1068                         vpd->device_identifier[j++] = page_83[i++];
1069                 break;
1070         default:
1071                 break;
1072         }
1073
1074         return transport_dump_vpd_ident(vpd, NULL, 0);
1075 }
1076 EXPORT_SYMBOL(transport_set_vpd_ident);
1077
1078 sense_reason_t
1079 target_cmd_size_check(struct se_cmd *cmd, unsigned int size)
1080 {
1081         struct se_device *dev = cmd->se_dev;
1082
1083         if (cmd->unknown_data_length) {
1084                 cmd->data_length = size;
1085         } else if (size != cmd->data_length) {
1086                 pr_warn("TARGET_CORE[%s]: Expected Transfer Length:"
1087                         " %u does not match SCSI CDB Length: %u for SAM Opcode:"
1088                         " 0x%02x\n", cmd->se_tfo->get_fabric_name(),
1089                                 cmd->data_length, size, cmd->t_task_cdb[0]);
1090
1091                 if (cmd->data_direction == DMA_TO_DEVICE &&
1092                     cmd->se_cmd_flags & SCF_SCSI_DATA_CDB) {
1093                         pr_err("Rejecting underflow/overflow WRITE data\n");
1094                         return TCM_INVALID_CDB_FIELD;
1095                 }
1096                 /*
1097                  * Reject READ_* or WRITE_* with overflow/underflow for
1098                  * type SCF_SCSI_DATA_CDB.
1099                  */
1100                 if (dev->dev_attrib.block_size != 512)  {
1101                         pr_err("Failing OVERFLOW/UNDERFLOW for LBA op"
1102                                 " CDB on non 512-byte sector setup subsystem"
1103                                 " plugin: %s\n", dev->transport->name);
1104                         /* Returns CHECK_CONDITION + INVALID_CDB_FIELD */
1105                         return TCM_INVALID_CDB_FIELD;
1106                 }
1107                 /*
1108                  * For the overflow case keep the existing fabric provided
1109                  * ->data_length.  Otherwise for the underflow case, reset
1110                  * ->data_length to the smaller SCSI expected data transfer
1111                  * length.
1112                  */
1113                 if (size > cmd->data_length) {
1114                         cmd->se_cmd_flags |= SCF_OVERFLOW_BIT;
1115                         cmd->residual_count = (size - cmd->data_length);
1116                 } else {
1117                         cmd->se_cmd_flags |= SCF_UNDERFLOW_BIT;
1118                         cmd->residual_count = (cmd->data_length - size);
1119                         cmd->data_length = size;
1120                 }
1121         }
1122
1123         return 0;
1124
1125 }
1126
1127 /*
1128  * Used by fabric modules containing a local struct se_cmd within their
1129  * fabric dependent per I/O descriptor.
1130  *
1131  * Preserves the value of @cmd->tag.
1132  */
1133 void transport_init_se_cmd(
1134         struct se_cmd *cmd,
1135         const struct target_core_fabric_ops *tfo,
1136         struct se_session *se_sess,
1137         u32 data_length,
1138         int data_direction,
1139         int task_attr,
1140         unsigned char *sense_buffer)
1141 {
1142         INIT_LIST_HEAD(&cmd->se_delayed_node);
1143         INIT_LIST_HEAD(&cmd->se_qf_node);
1144         INIT_LIST_HEAD(&cmd->se_cmd_list);
1145         INIT_LIST_HEAD(&cmd->state_list);
1146         init_completion(&cmd->t_transport_stop_comp);
1147         init_completion(&cmd->cmd_wait_comp);
1148         init_completion(&cmd->task_stop_comp);
1149         spin_lock_init(&cmd->t_state_lock);
1150         kref_init(&cmd->cmd_kref);
1151         cmd->transport_state = CMD_T_DEV_ACTIVE;
1152
1153         cmd->se_tfo = tfo;
1154         cmd->se_sess = se_sess;
1155         cmd->data_length = data_length;
1156         cmd->data_direction = data_direction;
1157         cmd->sam_task_attr = task_attr;
1158         cmd->sense_buffer = sense_buffer;
1159
1160         cmd->state_active = false;
1161 }
1162 EXPORT_SYMBOL(transport_init_se_cmd);
1163
1164 static sense_reason_t
1165 transport_check_alloc_task_attr(struct se_cmd *cmd)
1166 {
1167         struct se_device *dev = cmd->se_dev;
1168
1169         /*
1170          * Check if SAM Task Attribute emulation is enabled for this
1171          * struct se_device storage object
1172          */
1173         if (dev->transport->transport_flags & TRANSPORT_FLAG_PASSTHROUGH)
1174                 return 0;
1175
1176         if (cmd->sam_task_attr == TCM_ACA_TAG) {
1177                 pr_debug("SAM Task Attribute ACA"
1178                         " emulation is not supported\n");
1179                 return TCM_INVALID_CDB_FIELD;
1180         }
1181         /*
1182          * Used to determine when ORDERED commands should go from
1183          * Dormant to Active status.
1184          */
1185         cmd->se_ordered_id = atomic_inc_return(&dev->dev_ordered_id);
1186         pr_debug("Allocated se_ordered_id: %u for Task Attr: 0x%02x on %s\n",
1187                         cmd->se_ordered_id, cmd->sam_task_attr,
1188                         dev->transport->name);
1189         return 0;
1190 }
1191
1192 sense_reason_t
1193 target_setup_cmd_from_cdb(struct se_cmd *cmd, unsigned char *cdb)
1194 {
1195         struct se_device *dev = cmd->se_dev;
1196         sense_reason_t ret;
1197
1198         /*
1199          * Ensure that the received CDB is less than the max (252 + 8) bytes
1200          * for VARIABLE_LENGTH_CMD
1201          */
1202         if (scsi_command_size(cdb) > SCSI_MAX_VARLEN_CDB_SIZE) {
1203                 pr_err("Received SCSI CDB with command_size: %d that"
1204                         " exceeds SCSI_MAX_VARLEN_CDB_SIZE: %d\n",
1205                         scsi_command_size(cdb), SCSI_MAX_VARLEN_CDB_SIZE);
1206                 return TCM_INVALID_CDB_FIELD;
1207         }
1208         /*
1209          * If the received CDB is larger than TCM_MAX_COMMAND_SIZE,
1210          * allocate the additional extended CDB buffer now..  Otherwise
1211          * setup the pointer from __t_task_cdb to t_task_cdb.
1212          */
1213         if (scsi_command_size(cdb) > sizeof(cmd->__t_task_cdb)) {
1214                 cmd->t_task_cdb = kzalloc(scsi_command_size(cdb),
1215                                                 GFP_KERNEL);
1216                 if (!cmd->t_task_cdb) {
1217                         pr_err("Unable to allocate cmd->t_task_cdb"
1218                                 " %u > sizeof(cmd->__t_task_cdb): %lu ops\n",
1219                                 scsi_command_size(cdb),
1220                                 (unsigned long)sizeof(cmd->__t_task_cdb));
1221                         return TCM_OUT_OF_RESOURCES;
1222                 }
1223         } else
1224                 cmd->t_task_cdb = &cmd->__t_task_cdb[0];
1225         /*
1226          * Copy the original CDB into cmd->
1227          */
1228         memcpy(cmd->t_task_cdb, cdb, scsi_command_size(cdb));
1229
1230         trace_target_sequencer_start(cmd);
1231
1232         /*
1233          * Check for an existing UNIT ATTENTION condition
1234          */
1235         ret = target_scsi3_ua_check(cmd);
1236         if (ret)
1237                 return ret;
1238
1239         ret = target_alua_state_check(cmd);
1240         if (ret)
1241                 return ret;
1242
1243         ret = target_check_reservation(cmd);
1244         if (ret) {
1245                 cmd->scsi_status = SAM_STAT_RESERVATION_CONFLICT;
1246                 return ret;
1247         }
1248
1249         ret = dev->transport->parse_cdb(cmd);
1250         if (ret == TCM_UNSUPPORTED_SCSI_OPCODE)
1251                 pr_warn_ratelimited("%s/%s: Unsupported SCSI Opcode 0x%02x, sending CHECK_CONDITION.\n",
1252                                     cmd->se_tfo->get_fabric_name(),
1253                                     cmd->se_sess->se_node_acl->initiatorname,
1254                                     cmd->t_task_cdb[0]);
1255         if (ret)
1256                 return ret;
1257
1258         ret = transport_check_alloc_task_attr(cmd);
1259         if (ret)
1260                 return ret;
1261
1262         cmd->se_cmd_flags |= SCF_SUPPORTED_SAM_OPCODE;
1263         atomic_long_inc(&cmd->se_lun->lun_stats.cmd_pdus);
1264         return 0;
1265 }
1266 EXPORT_SYMBOL(target_setup_cmd_from_cdb);
1267
1268 /*
1269  * Used by fabric module frontends to queue tasks directly.
1270  * Many only be used from process context only
1271  */
1272 int transport_handle_cdb_direct(
1273         struct se_cmd *cmd)
1274 {
1275         sense_reason_t ret;
1276
1277         if (!cmd->se_lun) {
1278                 dump_stack();
1279                 pr_err("cmd->se_lun is NULL\n");
1280                 return -EINVAL;
1281         }
1282         if (in_interrupt()) {
1283                 dump_stack();
1284                 pr_err("transport_generic_handle_cdb cannot be called"
1285                                 " from interrupt context\n");
1286                 return -EINVAL;
1287         }
1288         /*
1289          * Set TRANSPORT_NEW_CMD state and CMD_T_ACTIVE to ensure that
1290          * outstanding descriptors are handled correctly during shutdown via
1291          * transport_wait_for_tasks()
1292          *
1293          * Also, we don't take cmd->t_state_lock here as we only expect
1294          * this to be called for initial descriptor submission.
1295          */
1296         cmd->t_state = TRANSPORT_NEW_CMD;
1297         cmd->transport_state |= CMD_T_ACTIVE;
1298
1299         /*
1300          * transport_generic_new_cmd() is already handling QUEUE_FULL,
1301          * so follow TRANSPORT_NEW_CMD processing thread context usage
1302          * and call transport_generic_request_failure() if necessary..
1303          */
1304         ret = transport_generic_new_cmd(cmd);
1305         if (ret)
1306                 transport_generic_request_failure(cmd, ret);
1307         return 0;
1308 }
1309 EXPORT_SYMBOL(transport_handle_cdb_direct);
1310
1311 sense_reason_t
1312 transport_generic_map_mem_to_cmd(struct se_cmd *cmd, struct scatterlist *sgl,
1313                 u32 sgl_count, struct scatterlist *sgl_bidi, u32 sgl_bidi_count)
1314 {
1315         if (!sgl || !sgl_count)
1316                 return 0;
1317
1318         /*
1319          * Reject SCSI data overflow with map_mem_to_cmd() as incoming
1320          * scatterlists already have been set to follow what the fabric
1321          * passes for the original expected data transfer length.
1322          */
1323         if (cmd->se_cmd_flags & SCF_OVERFLOW_BIT) {
1324                 pr_warn("Rejecting SCSI DATA overflow for fabric using"
1325                         " SCF_PASSTHROUGH_SG_TO_MEM_NOALLOC\n");
1326                 return TCM_INVALID_CDB_FIELD;
1327         }
1328
1329         cmd->t_data_sg = sgl;
1330         cmd->t_data_nents = sgl_count;
1331         cmd->t_bidi_data_sg = sgl_bidi;
1332         cmd->t_bidi_data_nents = sgl_bidi_count;
1333
1334         cmd->se_cmd_flags |= SCF_PASSTHROUGH_SG_TO_MEM_NOALLOC;
1335         return 0;
1336 }
1337
1338 /*
1339  * target_submit_cmd_map_sgls - lookup unpacked lun and submit uninitialized
1340  *                       se_cmd + use pre-allocated SGL memory.
1341  *
1342  * @se_cmd: command descriptor to submit
1343  * @se_sess: associated se_sess for endpoint
1344  * @cdb: pointer to SCSI CDB
1345  * @sense: pointer to SCSI sense buffer
1346  * @unpacked_lun: unpacked LUN to reference for struct se_lun
1347  * @data_length: fabric expected data transfer length
1348  * @task_addr: SAM task attribute
1349  * @data_dir: DMA data direction
1350  * @flags: flags for command submission from target_sc_flags_tables
1351  * @sgl: struct scatterlist memory for unidirectional mapping
1352  * @sgl_count: scatterlist count for unidirectional mapping
1353  * @sgl_bidi: struct scatterlist memory for bidirectional READ mapping
1354  * @sgl_bidi_count: scatterlist count for bidirectional READ mapping
1355  * @sgl_prot: struct scatterlist memory protection information
1356  * @sgl_prot_count: scatterlist count for protection information
1357  *
1358  * Task tags are supported if the caller has set @se_cmd->tag.
1359  *
1360  * Returns non zero to signal active I/O shutdown failure.  All other
1361  * setup exceptions will be returned as a SCSI CHECK_CONDITION response,
1362  * but still return zero here.
1363  *
1364  * This may only be called from process context, and also currently
1365  * assumes internal allocation of fabric payload buffer by target-core.
1366  */
1367 int target_submit_cmd_map_sgls(struct se_cmd *se_cmd, struct se_session *se_sess,
1368                 unsigned char *cdb, unsigned char *sense, u64 unpacked_lun,
1369                 u32 data_length, int task_attr, int data_dir, int flags,
1370                 struct scatterlist *sgl, u32 sgl_count,
1371                 struct scatterlist *sgl_bidi, u32 sgl_bidi_count,
1372                 struct scatterlist *sgl_prot, u32 sgl_prot_count)
1373 {
1374         struct se_portal_group *se_tpg;
1375         sense_reason_t rc;
1376         int ret;
1377
1378         se_tpg = se_sess->se_tpg;
1379         BUG_ON(!se_tpg);
1380         BUG_ON(se_cmd->se_tfo || se_cmd->se_sess);
1381         BUG_ON(in_interrupt());
1382         /*
1383          * Initialize se_cmd for target operation.  From this point
1384          * exceptions are handled by sending exception status via
1385          * target_core_fabric_ops->queue_status() callback
1386          */
1387         transport_init_se_cmd(se_cmd, se_tpg->se_tpg_tfo, se_sess,
1388                                 data_length, data_dir, task_attr, sense);
1389         if (flags & TARGET_SCF_UNKNOWN_SIZE)
1390                 se_cmd->unknown_data_length = 1;
1391         /*
1392          * Obtain struct se_cmd->cmd_kref reference and add new cmd to
1393          * se_sess->sess_cmd_list.  A second kref_get here is necessary
1394          * for fabrics using TARGET_SCF_ACK_KREF that expect a second
1395          * kref_put() to happen during fabric packet acknowledgement.
1396          */
1397         ret = target_get_sess_cmd(se_cmd, flags & TARGET_SCF_ACK_KREF);
1398         if (ret)
1399                 return ret;
1400         /*
1401          * Signal bidirectional data payloads to target-core
1402          */
1403         if (flags & TARGET_SCF_BIDI_OP)
1404                 se_cmd->se_cmd_flags |= SCF_BIDI;
1405         /*
1406          * Locate se_lun pointer and attach it to struct se_cmd
1407          */
1408         rc = transport_lookup_cmd_lun(se_cmd, unpacked_lun);
1409         if (rc) {
1410                 transport_send_check_condition_and_sense(se_cmd, rc, 0);
1411                 target_put_sess_cmd(se_cmd);
1412                 return 0;
1413         }
1414
1415         rc = target_setup_cmd_from_cdb(se_cmd, cdb);
1416         if (rc != 0) {
1417                 transport_generic_request_failure(se_cmd, rc);
1418                 return 0;
1419         }
1420
1421         /*
1422          * Save pointers for SGLs containing protection information,
1423          * if present.
1424          */
1425         if (sgl_prot_count) {
1426                 se_cmd->t_prot_sg = sgl_prot;
1427                 se_cmd->t_prot_nents = sgl_prot_count;
1428                 se_cmd->se_cmd_flags |= SCF_PASSTHROUGH_PROT_SG_TO_MEM_NOALLOC;
1429         }
1430
1431         /*
1432          * When a non zero sgl_count has been passed perform SGL passthrough
1433          * mapping for pre-allocated fabric memory instead of having target
1434          * core perform an internal SGL allocation..
1435          */
1436         if (sgl_count != 0) {
1437                 BUG_ON(!sgl);
1438
1439                 /*
1440                  * A work-around for tcm_loop as some userspace code via
1441                  * scsi-generic do not memset their associated read buffers,
1442                  * so go ahead and do that here for type non-data CDBs.  Also
1443                  * note that this is currently guaranteed to be a single SGL
1444                  * for this case by target core in target_setup_cmd_from_cdb()
1445                  * -> transport_generic_cmd_sequencer().
1446                  */
1447                 if (!(se_cmd->se_cmd_flags & SCF_SCSI_DATA_CDB) &&
1448                      se_cmd->data_direction == DMA_FROM_DEVICE) {
1449                         unsigned char *buf = NULL;
1450
1451                         if (sgl)
1452                                 buf = kmap(sg_page(sgl)) + sgl->offset;
1453
1454                         if (buf) {
1455                                 memset(buf, 0, sgl->length);
1456                                 kunmap(sg_page(sgl));
1457                         }
1458                 }
1459
1460                 rc = transport_generic_map_mem_to_cmd(se_cmd, sgl, sgl_count,
1461                                 sgl_bidi, sgl_bidi_count);
1462                 if (rc != 0) {
1463                         transport_generic_request_failure(se_cmd, rc);
1464                         return 0;
1465                 }
1466         }
1467
1468         /*
1469          * Check if we need to delay processing because of ALUA
1470          * Active/NonOptimized primary access state..
1471          */
1472         core_alua_check_nonop_delay(se_cmd);
1473
1474         transport_handle_cdb_direct(se_cmd);
1475         return 0;
1476 }
1477 EXPORT_SYMBOL(target_submit_cmd_map_sgls);
1478
1479 /*
1480  * target_submit_cmd - lookup unpacked lun and submit uninitialized se_cmd
1481  *
1482  * @se_cmd: command descriptor to submit
1483  * @se_sess: associated se_sess for endpoint
1484  * @cdb: pointer to SCSI CDB
1485  * @sense: pointer to SCSI sense buffer
1486  * @unpacked_lun: unpacked LUN to reference for struct se_lun
1487  * @data_length: fabric expected data transfer length
1488  * @task_addr: SAM task attribute
1489  * @data_dir: DMA data direction
1490  * @flags: flags for command submission from target_sc_flags_tables
1491  *
1492  * Task tags are supported if the caller has set @se_cmd->tag.
1493  *
1494  * Returns non zero to signal active I/O shutdown failure.  All other
1495  * setup exceptions will be returned as a SCSI CHECK_CONDITION response,
1496  * but still return zero here.
1497  *
1498  * This may only be called from process context, and also currently
1499  * assumes internal allocation of fabric payload buffer by target-core.
1500  *
1501  * It also assumes interal target core SGL memory allocation.
1502  */
1503 int target_submit_cmd(struct se_cmd *se_cmd, struct se_session *se_sess,
1504                 unsigned char *cdb, unsigned char *sense, u64 unpacked_lun,
1505                 u32 data_length, int task_attr, int data_dir, int flags)
1506 {
1507         return target_submit_cmd_map_sgls(se_cmd, se_sess, cdb, sense,
1508                         unpacked_lun, data_length, task_attr, data_dir,
1509                         flags, NULL, 0, NULL, 0, NULL, 0);
1510 }
1511 EXPORT_SYMBOL(target_submit_cmd);
1512
1513 static void target_complete_tmr_failure(struct work_struct *work)
1514 {
1515         struct se_cmd *se_cmd = container_of(work, struct se_cmd, work);
1516
1517         se_cmd->se_tmr_req->response = TMR_LUN_DOES_NOT_EXIST;
1518         se_cmd->se_tfo->queue_tm_rsp(se_cmd);
1519
1520         transport_cmd_check_stop_to_fabric(se_cmd);
1521 }
1522
1523 /**
1524  * target_submit_tmr - lookup unpacked lun and submit uninitialized se_cmd
1525  *                     for TMR CDBs
1526  *
1527  * @se_cmd: command descriptor to submit
1528  * @se_sess: associated se_sess for endpoint
1529  * @sense: pointer to SCSI sense buffer
1530  * @unpacked_lun: unpacked LUN to reference for struct se_lun
1531  * @fabric_context: fabric context for TMR req
1532  * @tm_type: Type of TM request
1533  * @gfp: gfp type for caller
1534  * @tag: referenced task tag for TMR_ABORT_TASK
1535  * @flags: submit cmd flags
1536  *
1537  * Callable from all contexts.
1538  **/
1539
1540 int target_submit_tmr(struct se_cmd *se_cmd, struct se_session *se_sess,
1541                 unsigned char *sense, u64 unpacked_lun,
1542                 void *fabric_tmr_ptr, unsigned char tm_type,
1543                 gfp_t gfp, unsigned int tag, int flags)
1544 {
1545         struct se_portal_group *se_tpg;
1546         int ret;
1547
1548         se_tpg = se_sess->se_tpg;
1549         BUG_ON(!se_tpg);
1550
1551         transport_init_se_cmd(se_cmd, se_tpg->se_tpg_tfo, se_sess,
1552                               0, DMA_NONE, TCM_SIMPLE_TAG, sense);
1553         /*
1554          * FIXME: Currently expect caller to handle se_cmd->se_tmr_req
1555          * allocation failure.
1556          */
1557         ret = core_tmr_alloc_req(se_cmd, fabric_tmr_ptr, tm_type, gfp);
1558         if (ret < 0)
1559                 return -ENOMEM;
1560
1561         if (tm_type == TMR_ABORT_TASK)
1562                 se_cmd->se_tmr_req->ref_task_tag = tag;
1563
1564         /* See target_submit_cmd for commentary */
1565         ret = target_get_sess_cmd(se_cmd, flags & TARGET_SCF_ACK_KREF);
1566         if (ret) {
1567                 core_tmr_release_req(se_cmd->se_tmr_req);
1568                 return ret;
1569         }
1570
1571         ret = transport_lookup_tmr_lun(se_cmd, unpacked_lun);
1572         if (ret) {
1573                 /*
1574                  * For callback during failure handling, push this work off
1575                  * to process context with TMR_LUN_DOES_NOT_EXIST status.
1576                  */
1577                 INIT_WORK(&se_cmd->work, target_complete_tmr_failure);
1578                 schedule_work(&se_cmd->work);
1579                 return 0;
1580         }
1581         transport_generic_handle_tmr(se_cmd);
1582         return 0;
1583 }
1584 EXPORT_SYMBOL(target_submit_tmr);
1585
1586 /*
1587  * If the cmd is active, request it to be stopped and sleep until it
1588  * has completed.
1589  */
1590 bool target_stop_cmd(struct se_cmd *cmd, unsigned long *flags)
1591         __releases(&cmd->t_state_lock)
1592         __acquires(&cmd->t_state_lock)
1593 {
1594         bool was_active = false;
1595
1596         if (cmd->transport_state & CMD_T_BUSY) {
1597                 cmd->transport_state |= CMD_T_REQUEST_STOP;
1598                 spin_unlock_irqrestore(&cmd->t_state_lock, *flags);
1599
1600                 pr_debug("cmd %p waiting to complete\n", cmd);
1601                 wait_for_completion(&cmd->task_stop_comp);
1602                 pr_debug("cmd %p stopped successfully\n", cmd);
1603
1604                 spin_lock_irqsave(&cmd->t_state_lock, *flags);
1605                 cmd->transport_state &= ~CMD_T_REQUEST_STOP;
1606                 cmd->transport_state &= ~CMD_T_BUSY;
1607                 was_active = true;
1608         }
1609
1610         return was_active;
1611 }
1612
1613 /*
1614  * Handle SAM-esque emulation for generic transport request failures.
1615  */
1616 void transport_generic_request_failure(struct se_cmd *cmd,
1617                 sense_reason_t sense_reason)
1618 {
1619         int ret = 0;
1620
1621         pr_debug("-----[ Storage Engine Exception for cmd: %p ITT: 0x%08llx"
1622                 " CDB: 0x%02x\n", cmd, cmd->tag, cmd->t_task_cdb[0]);
1623         pr_debug("-----[ i_state: %d t_state: %d sense_reason: %d\n",
1624                 cmd->se_tfo->get_cmd_state(cmd),
1625                 cmd->t_state, sense_reason);
1626         pr_debug("-----[ CMD_T_ACTIVE: %d CMD_T_STOP: %d CMD_T_SENT: %d\n",
1627                 (cmd->transport_state & CMD_T_ACTIVE) != 0,
1628                 (cmd->transport_state & CMD_T_STOP) != 0,
1629                 (cmd->transport_state & CMD_T_SENT) != 0);
1630
1631         /*
1632          * For SAM Task Attribute emulation for failed struct se_cmd
1633          */
1634         transport_complete_task_attr(cmd);
1635         /*
1636          * Handle special case for COMPARE_AND_WRITE failure, where the
1637          * callback is expected to drop the per device ->caw_sem.
1638          */
1639         if ((cmd->se_cmd_flags & SCF_COMPARE_AND_WRITE) &&
1640              cmd->transport_complete_callback)
1641                 cmd->transport_complete_callback(cmd, false);
1642
1643         switch (sense_reason) {
1644         case TCM_NON_EXISTENT_LUN:
1645         case TCM_UNSUPPORTED_SCSI_OPCODE:
1646         case TCM_INVALID_CDB_FIELD:
1647         case TCM_INVALID_PARAMETER_LIST:
1648         case TCM_PARAMETER_LIST_LENGTH_ERROR:
1649         case TCM_LOGICAL_UNIT_COMMUNICATION_FAILURE:
1650         case TCM_UNKNOWN_MODE_PAGE:
1651         case TCM_WRITE_PROTECTED:
1652         case TCM_ADDRESS_OUT_OF_RANGE:
1653         case TCM_CHECK_CONDITION_ABORT_CMD:
1654         case TCM_CHECK_CONDITION_UNIT_ATTENTION:
1655         case TCM_CHECK_CONDITION_NOT_READY:
1656         case TCM_LOGICAL_BLOCK_GUARD_CHECK_FAILED:
1657         case TCM_LOGICAL_BLOCK_APP_TAG_CHECK_FAILED:
1658         case TCM_LOGICAL_BLOCK_REF_TAG_CHECK_FAILED:
1659                 break;
1660         case TCM_OUT_OF_RESOURCES:
1661                 sense_reason = TCM_LOGICAL_UNIT_COMMUNICATION_FAILURE;
1662                 break;
1663         case TCM_RESERVATION_CONFLICT:
1664                 /*
1665                  * No SENSE Data payload for this case, set SCSI Status
1666                  * and queue the response to $FABRIC_MOD.
1667                  *
1668                  * Uses linux/include/scsi/scsi.h SAM status codes defs
1669                  */
1670                 cmd->scsi_status = SAM_STAT_RESERVATION_CONFLICT;
1671                 /*
1672                  * For UA Interlock Code 11b, a RESERVATION CONFLICT will
1673                  * establish a UNIT ATTENTION with PREVIOUS RESERVATION
1674                  * CONFLICT STATUS.
1675                  *
1676                  * See spc4r17, section 7.4.6 Control Mode Page, Table 349
1677                  */
1678                 if (cmd->se_sess &&
1679                     cmd->se_dev->dev_attrib.emulate_ua_intlck_ctrl == 2) {
1680                         target_ua_allocate_lun(cmd->se_sess->se_node_acl,
1681                                                cmd->orig_fe_lun, 0x2C,
1682                                         ASCQ_2CH_PREVIOUS_RESERVATION_CONFLICT_STATUS);
1683                 }
1684                 trace_target_cmd_complete(cmd);
1685                 ret = cmd->se_tfo->queue_status(cmd);
1686                 if (ret == -EAGAIN || ret == -ENOMEM)
1687                         goto queue_full;
1688                 goto check_stop;
1689         default:
1690                 pr_err("Unknown transport error for CDB 0x%02x: %d\n",
1691                         cmd->t_task_cdb[0], sense_reason);
1692                 sense_reason = TCM_UNSUPPORTED_SCSI_OPCODE;
1693                 break;
1694         }
1695
1696         ret = transport_send_check_condition_and_sense(cmd, sense_reason, 0);
1697         if (ret == -EAGAIN || ret == -ENOMEM)
1698                 goto queue_full;
1699
1700 check_stop:
1701         transport_lun_remove_cmd(cmd);
1702         if (!transport_cmd_check_stop_to_fabric(cmd))
1703                 ;
1704         return;
1705
1706 queue_full:
1707         cmd->t_state = TRANSPORT_COMPLETE_QF_OK;
1708         transport_handle_queue_full(cmd, cmd->se_dev);
1709 }
1710 EXPORT_SYMBOL(transport_generic_request_failure);
1711
1712 void __target_execute_cmd(struct se_cmd *cmd)
1713 {
1714         sense_reason_t ret;
1715
1716         if (cmd->execute_cmd) {
1717                 ret = cmd->execute_cmd(cmd);
1718                 if (ret) {
1719                         spin_lock_irq(&cmd->t_state_lock);
1720                         cmd->transport_state &= ~(CMD_T_BUSY|CMD_T_SENT);
1721                         spin_unlock_irq(&cmd->t_state_lock);
1722
1723                         transport_generic_request_failure(cmd, ret);
1724                 }
1725         }
1726 }
1727
1728 static int target_write_prot_action(struct se_cmd *cmd)
1729 {
1730         u32 sectors;
1731         /*
1732          * Perform WRITE_INSERT of PI using software emulation when backend
1733          * device has PI enabled, if the transport has not already generated
1734          * PI using hardware WRITE_INSERT offload.
1735          */
1736         switch (cmd->prot_op) {
1737         case TARGET_PROT_DOUT_INSERT:
1738                 if (!(cmd->se_sess->sup_prot_ops & TARGET_PROT_DOUT_INSERT))
1739                         sbc_dif_generate(cmd);
1740                 break;
1741         case TARGET_PROT_DOUT_STRIP:
1742                 if (cmd->se_sess->sup_prot_ops & TARGET_PROT_DOUT_STRIP)
1743                         break;
1744
1745                 sectors = cmd->data_length >> ilog2(cmd->se_dev->dev_attrib.block_size);
1746                 cmd->pi_err = sbc_dif_verify(cmd, cmd->t_task_lba,
1747                                              sectors, 0, cmd->t_prot_sg, 0);
1748                 if (unlikely(cmd->pi_err)) {
1749                         spin_lock_irq(&cmd->t_state_lock);
1750                         cmd->transport_state &= ~(CMD_T_BUSY|CMD_T_SENT);
1751                         spin_unlock_irq(&cmd->t_state_lock);
1752                         transport_generic_request_failure(cmd, cmd->pi_err);
1753                         return -1;
1754                 }
1755                 break;
1756         default:
1757                 break;
1758         }
1759
1760         return 0;
1761 }
1762
1763 static bool target_handle_task_attr(struct se_cmd *cmd)
1764 {
1765         struct se_device *dev = cmd->se_dev;
1766
1767         if (dev->transport->transport_flags & TRANSPORT_FLAG_PASSTHROUGH)
1768                 return false;
1769
1770         /*
1771          * Check for the existence of HEAD_OF_QUEUE, and if true return 1
1772          * to allow the passed struct se_cmd list of tasks to the front of the list.
1773          */
1774         switch (cmd->sam_task_attr) {
1775         case TCM_HEAD_TAG:
1776                 pr_debug("Added HEAD_OF_QUEUE for CDB: 0x%02x, "
1777                          "se_ordered_id: %u\n",
1778                          cmd->t_task_cdb[0], cmd->se_ordered_id);
1779                 return false;
1780         case TCM_ORDERED_TAG:
1781                 atomic_inc_mb(&dev->dev_ordered_sync);
1782
1783                 pr_debug("Added ORDERED for CDB: 0x%02x to ordered list, "
1784                          " se_ordered_id: %u\n",
1785                          cmd->t_task_cdb[0], cmd->se_ordered_id);
1786
1787                 /*
1788                  * Execute an ORDERED command if no other older commands
1789                  * exist that need to be completed first.
1790                  */
1791                 if (!atomic_read(&dev->simple_cmds))
1792                         return false;
1793                 break;
1794         default:
1795                 /*
1796                  * For SIMPLE and UNTAGGED Task Attribute commands
1797                  */
1798                 atomic_inc_mb(&dev->simple_cmds);
1799                 break;
1800         }
1801
1802         if (atomic_read(&dev->dev_ordered_sync) == 0)
1803                 return false;
1804
1805         spin_lock(&dev->delayed_cmd_lock);
1806         list_add_tail(&cmd->se_delayed_node, &dev->delayed_cmd_list);
1807         spin_unlock(&dev->delayed_cmd_lock);
1808
1809         pr_debug("Added CDB: 0x%02x Task Attr: 0x%02x to"
1810                 " delayed CMD list, se_ordered_id: %u\n",
1811                 cmd->t_task_cdb[0], cmd->sam_task_attr,
1812                 cmd->se_ordered_id);
1813         return true;
1814 }
1815
1816 void target_execute_cmd(struct se_cmd *cmd)
1817 {
1818         /*
1819          * If the received CDB has aleady been aborted stop processing it here.
1820          */
1821         if (transport_check_aborted_status(cmd, 1))
1822                 return;
1823
1824         /*
1825          * Determine if frontend context caller is requesting the stopping of
1826          * this command for frontend exceptions.
1827          */
1828         spin_lock_irq(&cmd->t_state_lock);
1829         if (cmd->transport_state & CMD_T_STOP) {
1830                 pr_debug("%s:%d CMD_T_STOP for ITT: 0x%08llx\n",
1831                         __func__, __LINE__, cmd->tag);
1832
1833                 spin_unlock_irq(&cmd->t_state_lock);
1834                 complete_all(&cmd->t_transport_stop_comp);
1835                 return;
1836         }
1837
1838         cmd->t_state = TRANSPORT_PROCESSING;
1839         cmd->transport_state |= CMD_T_ACTIVE|CMD_T_BUSY|CMD_T_SENT;
1840         spin_unlock_irq(&cmd->t_state_lock);
1841
1842         if (target_write_prot_action(cmd))
1843                 return;
1844
1845         if (target_handle_task_attr(cmd)) {
1846                 spin_lock_irq(&cmd->t_state_lock);
1847                 cmd->transport_state &= ~(CMD_T_BUSY | CMD_T_SENT);
1848                 spin_unlock_irq(&cmd->t_state_lock);
1849                 return;
1850         }
1851
1852         __target_execute_cmd(cmd);
1853 }
1854 EXPORT_SYMBOL(target_execute_cmd);
1855
1856 /*
1857  * Process all commands up to the last received ORDERED task attribute which
1858  * requires another blocking boundary
1859  */
1860 static void target_restart_delayed_cmds(struct se_device *dev)
1861 {
1862         for (;;) {
1863                 struct se_cmd *cmd;
1864
1865                 spin_lock(&dev->delayed_cmd_lock);
1866                 if (list_empty(&dev->delayed_cmd_list)) {
1867                         spin_unlock(&dev->delayed_cmd_lock);
1868                         break;
1869                 }
1870
1871                 cmd = list_entry(dev->delayed_cmd_list.next,
1872                                  struct se_cmd, se_delayed_node);
1873                 list_del(&cmd->se_delayed_node);
1874                 spin_unlock(&dev->delayed_cmd_lock);
1875
1876                 __target_execute_cmd(cmd);
1877
1878                 if (cmd->sam_task_attr == TCM_ORDERED_TAG)
1879                         break;
1880         }
1881 }
1882
1883 /*
1884  * Called from I/O completion to determine which dormant/delayed
1885  * and ordered cmds need to have their tasks added to the execution queue.
1886  */
1887 static void transport_complete_task_attr(struct se_cmd *cmd)
1888 {
1889         struct se_device *dev = cmd->se_dev;
1890
1891         if (dev->transport->transport_flags & TRANSPORT_FLAG_PASSTHROUGH)
1892                 return;
1893
1894         if (cmd->sam_task_attr == TCM_SIMPLE_TAG) {
1895                 atomic_dec_mb(&dev->simple_cmds);
1896                 dev->dev_cur_ordered_id++;
1897                 pr_debug("Incremented dev->dev_cur_ordered_id: %u for"
1898                         " SIMPLE: %u\n", dev->dev_cur_ordered_id,
1899                         cmd->se_ordered_id);
1900         } else if (cmd->sam_task_attr == TCM_HEAD_TAG) {
1901                 dev->dev_cur_ordered_id++;
1902                 pr_debug("Incremented dev_cur_ordered_id: %u for"
1903                         " HEAD_OF_QUEUE: %u\n", dev->dev_cur_ordered_id,
1904                         cmd->se_ordered_id);
1905         } else if (cmd->sam_task_attr == TCM_ORDERED_TAG) {
1906                 atomic_dec_mb(&dev->dev_ordered_sync);
1907
1908                 dev->dev_cur_ordered_id++;
1909                 pr_debug("Incremented dev_cur_ordered_id: %u for ORDERED:"
1910                         " %u\n", dev->dev_cur_ordered_id, cmd->se_ordered_id);
1911         }
1912
1913         target_restart_delayed_cmds(dev);
1914 }
1915
1916 static void transport_complete_qf(struct se_cmd *cmd)
1917 {
1918         int ret = 0;
1919
1920         transport_complete_task_attr(cmd);
1921
1922         if (cmd->se_cmd_flags & SCF_TRANSPORT_TASK_SENSE) {
1923                 trace_target_cmd_complete(cmd);
1924                 ret = cmd->se_tfo->queue_status(cmd);
1925                 goto out;
1926         }
1927
1928         switch (cmd->data_direction) {
1929         case DMA_FROM_DEVICE:
1930                 trace_target_cmd_complete(cmd);
1931                 ret = cmd->se_tfo->queue_data_in(cmd);
1932                 break;
1933         case DMA_TO_DEVICE:
1934                 if (cmd->se_cmd_flags & SCF_BIDI) {
1935                         ret = cmd->se_tfo->queue_data_in(cmd);
1936                         break;
1937                 }
1938                 /* Fall through for DMA_TO_DEVICE */
1939         case DMA_NONE:
1940                 trace_target_cmd_complete(cmd);
1941                 ret = cmd->se_tfo->queue_status(cmd);
1942                 break;
1943         default:
1944                 break;
1945         }
1946
1947 out:
1948         if (ret < 0) {
1949                 transport_handle_queue_full(cmd, cmd->se_dev);
1950                 return;
1951         }
1952         transport_lun_remove_cmd(cmd);
1953         transport_cmd_check_stop_to_fabric(cmd);
1954 }
1955
1956 static void transport_handle_queue_full(
1957         struct se_cmd *cmd,
1958         struct se_device *dev)
1959 {
1960         spin_lock_irq(&dev->qf_cmd_lock);
1961         list_add_tail(&cmd->se_qf_node, &cmd->se_dev->qf_cmd_list);
1962         atomic_inc_mb(&dev->dev_qf_count);
1963         spin_unlock_irq(&cmd->se_dev->qf_cmd_lock);
1964
1965         schedule_work(&cmd->se_dev->qf_work_queue);
1966 }
1967
1968 static bool target_read_prot_action(struct se_cmd *cmd)
1969 {
1970         switch (cmd->prot_op) {
1971         case TARGET_PROT_DIN_STRIP:
1972                 if (!(cmd->se_sess->sup_prot_ops & TARGET_PROT_DIN_STRIP)) {
1973                         u32 sectors = cmd->data_length >>
1974                                   ilog2(cmd->se_dev->dev_attrib.block_size);
1975
1976                         cmd->pi_err = sbc_dif_verify(cmd, cmd->t_task_lba,
1977                                                      sectors, 0, cmd->t_prot_sg,
1978                                                      0);
1979                         if (cmd->pi_err)
1980                                 return true;
1981                 }
1982                 break;
1983         case TARGET_PROT_DIN_INSERT:
1984                 if (cmd->se_sess->sup_prot_ops & TARGET_PROT_DIN_INSERT)
1985                         break;
1986
1987                 sbc_dif_generate(cmd);
1988                 break;
1989         default:
1990                 break;
1991         }
1992
1993         return false;
1994 }
1995
1996 static void target_complete_ok_work(struct work_struct *work)
1997 {
1998         struct se_cmd *cmd = container_of(work, struct se_cmd, work);
1999         int ret;
2000
2001         /*
2002          * Check if we need to move delayed/dormant tasks from cmds on the
2003          * delayed execution list after a HEAD_OF_QUEUE or ORDERED Task
2004          * Attribute.
2005          */
2006         transport_complete_task_attr(cmd);
2007
2008         /*
2009          * Check to schedule QUEUE_FULL work, or execute an existing
2010          * cmd->transport_qf_callback()
2011          */
2012         if (atomic_read(&cmd->se_dev->dev_qf_count) != 0)
2013                 schedule_work(&cmd->se_dev->qf_work_queue);
2014
2015         /*
2016          * Check if we need to send a sense buffer from
2017          * the struct se_cmd in question.
2018          */
2019         if (cmd->se_cmd_flags & SCF_TRANSPORT_TASK_SENSE) {
2020                 WARN_ON(!cmd->scsi_status);
2021                 ret = transport_send_check_condition_and_sense(
2022                                         cmd, 0, 1);
2023                 if (ret == -EAGAIN || ret == -ENOMEM)
2024                         goto queue_full;
2025
2026                 transport_lun_remove_cmd(cmd);
2027                 transport_cmd_check_stop_to_fabric(cmd);
2028                 return;
2029         }
2030         /*
2031          * Check for a callback, used by amongst other things
2032          * XDWRITE_READ_10 and COMPARE_AND_WRITE emulation.
2033          */
2034         if (cmd->transport_complete_callback) {
2035                 sense_reason_t rc;
2036
2037                 rc = cmd->transport_complete_callback(cmd, true);
2038                 if (!rc && !(cmd->se_cmd_flags & SCF_COMPARE_AND_WRITE_POST)) {
2039                         if ((cmd->se_cmd_flags & SCF_COMPARE_AND_WRITE) &&
2040                             !cmd->data_length)
2041                                 goto queue_rsp;
2042
2043                         return;
2044                 } else if (rc) {
2045                         ret = transport_send_check_condition_and_sense(cmd,
2046                                                 rc, 0);
2047                         if (ret == -EAGAIN || ret == -ENOMEM)
2048                                 goto queue_full;
2049
2050                         transport_lun_remove_cmd(cmd);
2051                         transport_cmd_check_stop_to_fabric(cmd);
2052                         return;
2053                 }
2054         }
2055
2056 queue_rsp:
2057         switch (cmd->data_direction) {
2058         case DMA_FROM_DEVICE:
2059                 atomic_long_add(cmd->data_length,
2060                                 &cmd->se_lun->lun_stats.tx_data_octets);
2061                 /*
2062                  * Perform READ_STRIP of PI using software emulation when
2063                  * backend had PI enabled, if the transport will not be
2064                  * performing hardware READ_STRIP offload.
2065                  */
2066                 if (target_read_prot_action(cmd)) {
2067                         ret = transport_send_check_condition_and_sense(cmd,
2068                                                 cmd->pi_err, 0);
2069                         if (ret == -EAGAIN || ret == -ENOMEM)
2070                                 goto queue_full;
2071
2072                         transport_lun_remove_cmd(cmd);
2073                         transport_cmd_check_stop_to_fabric(cmd);
2074                         return;
2075                 }
2076
2077                 trace_target_cmd_complete(cmd);
2078                 ret = cmd->se_tfo->queue_data_in(cmd);
2079                 if (ret == -EAGAIN || ret == -ENOMEM)
2080                         goto queue_full;
2081                 break;
2082         case DMA_TO_DEVICE:
2083                 atomic_long_add(cmd->data_length,
2084                                 &cmd->se_lun->lun_stats.rx_data_octets);
2085                 /*
2086                  * Check if we need to send READ payload for BIDI-COMMAND
2087                  */
2088                 if (cmd->se_cmd_flags & SCF_BIDI) {
2089                         atomic_long_add(cmd->data_length,
2090                                         &cmd->se_lun->lun_stats.tx_data_octets);
2091                         ret = cmd->se_tfo->queue_data_in(cmd);
2092                         if (ret == -EAGAIN || ret == -ENOMEM)
2093                                 goto queue_full;
2094                         break;
2095                 }
2096                 /* Fall through for DMA_TO_DEVICE */
2097         case DMA_NONE:
2098                 trace_target_cmd_complete(cmd);
2099                 ret = cmd->se_tfo->queue_status(cmd);
2100                 if (ret == -EAGAIN || ret == -ENOMEM)
2101                         goto queue_full;
2102                 break;
2103         default:
2104                 break;
2105         }
2106
2107         transport_lun_remove_cmd(cmd);
2108         transport_cmd_check_stop_to_fabric(cmd);
2109         return;
2110
2111 queue_full:
2112         pr_debug("Handling complete_ok QUEUE_FULL: se_cmd: %p,"
2113                 " data_direction: %d\n", cmd, cmd->data_direction);
2114         cmd->t_state = TRANSPORT_COMPLETE_QF_OK;
2115         transport_handle_queue_full(cmd, cmd->se_dev);
2116 }
2117
2118 static inline void transport_free_sgl(struct scatterlist *sgl, int nents)
2119 {
2120         struct scatterlist *sg;
2121         int count;
2122
2123         for_each_sg(sgl, sg, nents, count)
2124                 __free_page(sg_page(sg));
2125
2126         kfree(sgl);
2127 }
2128
2129 static inline void transport_reset_sgl_orig(struct se_cmd *cmd)
2130 {
2131         /*
2132          * Check for saved t_data_sg that may be used for COMPARE_AND_WRITE
2133          * emulation, and free + reset pointers if necessary..
2134          */
2135         if (!cmd->t_data_sg_orig)
2136                 return;
2137
2138         kfree(cmd->t_data_sg);
2139         cmd->t_data_sg = cmd->t_data_sg_orig;
2140         cmd->t_data_sg_orig = NULL;
2141         cmd->t_data_nents = cmd->t_data_nents_orig;
2142         cmd->t_data_nents_orig = 0;
2143 }
2144
2145 static inline void transport_free_pages(struct se_cmd *cmd)
2146 {
2147         if (!(cmd->se_cmd_flags & SCF_PASSTHROUGH_PROT_SG_TO_MEM_NOALLOC)) {
2148                 transport_free_sgl(cmd->t_prot_sg, cmd->t_prot_nents);
2149                 cmd->t_prot_sg = NULL;
2150                 cmd->t_prot_nents = 0;
2151         }
2152
2153         if (cmd->se_cmd_flags & SCF_PASSTHROUGH_SG_TO_MEM_NOALLOC) {
2154                 /*
2155                  * Release special case READ buffer payload required for
2156                  * SG_TO_MEM_NOALLOC to function with COMPARE_AND_WRITE
2157                  */
2158                 if (cmd->se_cmd_flags & SCF_COMPARE_AND_WRITE) {
2159                         transport_free_sgl(cmd->t_bidi_data_sg,
2160                                            cmd->t_bidi_data_nents);
2161                         cmd->t_bidi_data_sg = NULL;
2162                         cmd->t_bidi_data_nents = 0;
2163                 }
2164                 transport_reset_sgl_orig(cmd);
2165                 return;
2166         }
2167         transport_reset_sgl_orig(cmd);
2168
2169         transport_free_sgl(cmd->t_data_sg, cmd->t_data_nents);
2170         cmd->t_data_sg = NULL;
2171         cmd->t_data_nents = 0;
2172
2173         transport_free_sgl(cmd->t_bidi_data_sg, cmd->t_bidi_data_nents);
2174         cmd->t_bidi_data_sg = NULL;
2175         cmd->t_bidi_data_nents = 0;
2176 }
2177
2178 /**
2179  * transport_release_cmd - free a command
2180  * @cmd:       command to free
2181  *
2182  * This routine unconditionally frees a command, and reference counting
2183  * or list removal must be done in the caller.
2184  */
2185 static int transport_release_cmd(struct se_cmd *cmd)
2186 {
2187         BUG_ON(!cmd->se_tfo);
2188
2189         if (cmd->se_cmd_flags & SCF_SCSI_TMR_CDB)
2190                 core_tmr_release_req(cmd->se_tmr_req);
2191         if (cmd->t_task_cdb != cmd->__t_task_cdb)
2192                 kfree(cmd->t_task_cdb);
2193         /*
2194          * If this cmd has been setup with target_get_sess_cmd(), drop
2195          * the kref and call ->release_cmd() in kref callback.
2196          */
2197         return target_put_sess_cmd(cmd);
2198 }
2199
2200 /**
2201  * transport_put_cmd - release a reference to a command
2202  * @cmd:       command to release
2203  *
2204  * This routine releases our reference to the command and frees it if possible.
2205  */
2206 static int transport_put_cmd(struct se_cmd *cmd)
2207 {
2208         transport_free_pages(cmd);
2209         return transport_release_cmd(cmd);
2210 }
2211
2212 void *transport_kmap_data_sg(struct se_cmd *cmd)
2213 {
2214         struct scatterlist *sg = cmd->t_data_sg;
2215         struct page **pages;
2216         int i;
2217
2218         /*
2219          * We need to take into account a possible offset here for fabrics like
2220          * tcm_loop who may be using a contig buffer from the SCSI midlayer for
2221          * control CDBs passed as SGLs via transport_generic_map_mem_to_cmd()
2222          */
2223         if (!cmd->t_data_nents)
2224                 return NULL;
2225
2226         BUG_ON(!sg);
2227         if (cmd->t_data_nents == 1)
2228                 return kmap(sg_page(sg)) + sg->offset;
2229
2230         /* >1 page. use vmap */
2231         pages = kmalloc(sizeof(*pages) * cmd->t_data_nents, GFP_KERNEL);
2232         if (!pages)
2233                 return NULL;
2234
2235         /* convert sg[] to pages[] */
2236         for_each_sg(cmd->t_data_sg, sg, cmd->t_data_nents, i) {
2237                 pages[i] = sg_page(sg);
2238         }
2239
2240         cmd->t_data_vmap = vmap(pages, cmd->t_data_nents,  VM_MAP, PAGE_KERNEL);
2241         kfree(pages);
2242         if (!cmd->t_data_vmap)
2243                 return NULL;
2244
2245         return cmd->t_data_vmap + cmd->t_data_sg[0].offset;
2246 }
2247 EXPORT_SYMBOL(transport_kmap_data_sg);
2248
2249 void transport_kunmap_data_sg(struct se_cmd *cmd)
2250 {
2251         if (!cmd->t_data_nents) {
2252                 return;
2253         } else if (cmd->t_data_nents == 1) {
2254                 kunmap(sg_page(cmd->t_data_sg));
2255                 return;
2256         }
2257
2258         vunmap(cmd->t_data_vmap);
2259         cmd->t_data_vmap = NULL;
2260 }
2261 EXPORT_SYMBOL(transport_kunmap_data_sg);
2262
2263 int
2264 target_alloc_sgl(struct scatterlist **sgl, unsigned int *nents, u32 length,
2265                  bool zero_page)
2266 {
2267         struct scatterlist *sg;
2268         struct page *page;
2269         gfp_t zero_flag = (zero_page) ? __GFP_ZERO : 0;
2270         unsigned int nent;
2271         int i = 0;
2272
2273         nent = DIV_ROUND_UP(length, PAGE_SIZE);
2274         sg = kmalloc(sizeof(struct scatterlist) * nent, GFP_KERNEL);
2275         if (!sg)
2276                 return -ENOMEM;
2277
2278         sg_init_table(sg, nent);
2279
2280         while (length) {
2281                 u32 page_len = min_t(u32, length, PAGE_SIZE);
2282                 page = alloc_page(GFP_KERNEL | zero_flag);
2283                 if (!page)
2284                         goto out;
2285
2286                 sg_set_page(&sg[i], page, page_len, 0);
2287                 length -= page_len;
2288                 i++;
2289         }
2290         *sgl = sg;
2291         *nents = nent;
2292         return 0;
2293
2294 out:
2295         while (i > 0) {
2296                 i--;
2297                 __free_page(sg_page(&sg[i]));
2298         }
2299         kfree(sg);
2300         return -ENOMEM;
2301 }
2302
2303 /*
2304  * Allocate any required resources to execute the command.  For writes we
2305  * might not have the payload yet, so notify the fabric via a call to
2306  * ->write_pending instead. Otherwise place it on the execution queue.
2307  */
2308 sense_reason_t
2309 transport_generic_new_cmd(struct se_cmd *cmd)
2310 {
2311         int ret = 0;
2312         bool zero_flag = !(cmd->se_cmd_flags & SCF_SCSI_DATA_CDB);
2313
2314         if (cmd->prot_op != TARGET_PROT_NORMAL &&
2315             !(cmd->se_cmd_flags & SCF_PASSTHROUGH_PROT_SG_TO_MEM_NOALLOC)) {
2316                 ret = target_alloc_sgl(&cmd->t_prot_sg, &cmd->t_prot_nents,
2317                                        cmd->prot_length, true);
2318                 if (ret < 0)
2319                         return TCM_LOGICAL_UNIT_COMMUNICATION_FAILURE;
2320         }
2321
2322         /*
2323          * Determine is the TCM fabric module has already allocated physical
2324          * memory, and is directly calling transport_generic_map_mem_to_cmd()
2325          * beforehand.
2326          */
2327         if (!(cmd->se_cmd_flags & SCF_PASSTHROUGH_SG_TO_MEM_NOALLOC) &&
2328             cmd->data_length) {
2329
2330                 if ((cmd->se_cmd_flags & SCF_BIDI) ||
2331                     (cmd->se_cmd_flags & SCF_COMPARE_AND_WRITE)) {
2332                         u32 bidi_length;
2333
2334                         if (cmd->se_cmd_flags & SCF_COMPARE_AND_WRITE)
2335                                 bidi_length = cmd->t_task_nolb *
2336                                               cmd->se_dev->dev_attrib.block_size;
2337                         else
2338                                 bidi_length = cmd->data_length;
2339
2340                         ret = target_alloc_sgl(&cmd->t_bidi_data_sg,
2341                                                &cmd->t_bidi_data_nents,
2342                                                bidi_length, zero_flag);
2343                         if (ret < 0)
2344                                 return TCM_LOGICAL_UNIT_COMMUNICATION_FAILURE;
2345                 }
2346
2347                 ret = target_alloc_sgl(&cmd->t_data_sg, &cmd->t_data_nents,
2348                                        cmd->data_length, zero_flag);
2349                 if (ret < 0)
2350                         return TCM_LOGICAL_UNIT_COMMUNICATION_FAILURE;
2351         } else if ((cmd->se_cmd_flags & SCF_COMPARE_AND_WRITE) &&
2352                     cmd->data_length) {
2353                 /*
2354                  * Special case for COMPARE_AND_WRITE with fabrics
2355                  * using SCF_PASSTHROUGH_SG_TO_MEM_NOALLOC.
2356                  */
2357                 u32 caw_length = cmd->t_task_nolb *
2358                                  cmd->se_dev->dev_attrib.block_size;
2359
2360                 ret = target_alloc_sgl(&cmd->t_bidi_data_sg,
2361                                        &cmd->t_bidi_data_nents,
2362                                        caw_length, zero_flag);
2363                 if (ret < 0)
2364                         return TCM_LOGICAL_UNIT_COMMUNICATION_FAILURE;
2365         }
2366         /*
2367          * If this command is not a write we can execute it right here,
2368          * for write buffers we need to notify the fabric driver first
2369          * and let it call back once the write buffers are ready.
2370          */
2371         target_add_to_state_list(cmd);
2372         if (cmd->data_direction != DMA_TO_DEVICE || cmd->data_length == 0) {
2373                 target_execute_cmd(cmd);
2374                 return 0;
2375         }
2376         transport_cmd_check_stop(cmd, false, true);
2377
2378         ret = cmd->se_tfo->write_pending(cmd);
2379         if (ret == -EAGAIN || ret == -ENOMEM)
2380                 goto queue_full;
2381
2382         /* fabric drivers should only return -EAGAIN or -ENOMEM as error */
2383         WARN_ON(ret);
2384
2385         return (!ret) ? 0 : TCM_LOGICAL_UNIT_COMMUNICATION_FAILURE;
2386
2387 queue_full:
2388         pr_debug("Handling write_pending QUEUE__FULL: se_cmd: %p\n", cmd);
2389         cmd->t_state = TRANSPORT_COMPLETE_QF_WP;
2390         transport_handle_queue_full(cmd, cmd->se_dev);
2391         return 0;
2392 }
2393 EXPORT_SYMBOL(transport_generic_new_cmd);
2394
2395 static void transport_write_pending_qf(struct se_cmd *cmd)
2396 {
2397         int ret;
2398
2399         ret = cmd->se_tfo->write_pending(cmd);
2400         if (ret == -EAGAIN || ret == -ENOMEM) {
2401                 pr_debug("Handling write_pending QUEUE__FULL: se_cmd: %p\n",
2402                          cmd);
2403                 transport_handle_queue_full(cmd, cmd->se_dev);
2404         }
2405 }
2406
2407 int transport_generic_free_cmd(struct se_cmd *cmd, int wait_for_tasks)
2408 {
2409         unsigned long flags;
2410         int ret = 0;
2411
2412         if (!(cmd->se_cmd_flags & SCF_SE_LUN_CMD)) {
2413                 if (wait_for_tasks && (cmd->se_cmd_flags & SCF_SCSI_TMR_CDB))
2414                          transport_wait_for_tasks(cmd);
2415
2416                 ret = transport_release_cmd(cmd);
2417         } else {
2418                 if (wait_for_tasks)
2419                         transport_wait_for_tasks(cmd);
2420                 /*
2421                  * Handle WRITE failure case where transport_generic_new_cmd()
2422                  * has already added se_cmd to state_list, but fabric has
2423                  * failed command before I/O submission.
2424                  */
2425                 if (cmd->state_active) {
2426                         spin_lock_irqsave(&cmd->t_state_lock, flags);
2427                         target_remove_from_state_list(cmd);
2428                         spin_unlock_irqrestore(&cmd->t_state_lock, flags);
2429                 }
2430
2431                 if (cmd->se_lun)
2432                         transport_lun_remove_cmd(cmd);
2433
2434                 ret = transport_put_cmd(cmd);
2435         }
2436         return ret;
2437 }
2438 EXPORT_SYMBOL(transport_generic_free_cmd);
2439
2440 /* target_get_sess_cmd - Add command to active ->sess_cmd_list
2441  * @se_cmd:     command descriptor to add
2442  * @ack_kref:   Signal that fabric will perform an ack target_put_sess_cmd()
2443  */
2444 int target_get_sess_cmd(struct se_cmd *se_cmd, bool ack_kref)
2445 {
2446         struct se_session *se_sess = se_cmd->se_sess;
2447         unsigned long flags;
2448         int ret = 0;
2449
2450         /*
2451          * Add a second kref if the fabric caller is expecting to handle
2452          * fabric acknowledgement that requires two target_put_sess_cmd()
2453          * invocations before se_cmd descriptor release.
2454          */
2455         if (ack_kref)
2456                 kref_get(&se_cmd->cmd_kref);
2457
2458         spin_lock_irqsave(&se_sess->sess_cmd_lock, flags);
2459         if (se_sess->sess_tearing_down) {
2460                 ret = -ESHUTDOWN;
2461                 goto out;
2462         }
2463         list_add_tail(&se_cmd->se_cmd_list, &se_sess->sess_cmd_list);
2464 out:
2465         spin_unlock_irqrestore(&se_sess->sess_cmd_lock, flags);
2466
2467         if (ret && ack_kref)
2468                 target_put_sess_cmd(se_cmd);
2469
2470         return ret;
2471 }
2472 EXPORT_SYMBOL(target_get_sess_cmd);
2473
2474 static void target_release_cmd_kref(struct kref *kref)
2475                 __releases(&se_cmd->se_sess->sess_cmd_lock)
2476 {
2477         struct se_cmd *se_cmd = container_of(kref, struct se_cmd, cmd_kref);
2478         struct se_session *se_sess = se_cmd->se_sess;
2479
2480         if (list_empty(&se_cmd->se_cmd_list)) {
2481                 spin_unlock(&se_sess->sess_cmd_lock);
2482                 se_cmd->se_tfo->release_cmd(se_cmd);
2483                 return;
2484         }
2485         if (se_sess->sess_tearing_down && se_cmd->cmd_wait_set) {
2486                 spin_unlock(&se_sess->sess_cmd_lock);
2487                 complete(&se_cmd->cmd_wait_comp);
2488                 return;
2489         }
2490         list_del(&se_cmd->se_cmd_list);
2491         spin_unlock(&se_sess->sess_cmd_lock);
2492
2493         se_cmd->se_tfo->release_cmd(se_cmd);
2494 }
2495
2496 /* target_put_sess_cmd - Check for active I/O shutdown via kref_put
2497  * @se_cmd:     command descriptor to drop
2498  */
2499 int target_put_sess_cmd(struct se_cmd *se_cmd)
2500 {
2501         struct se_session *se_sess = se_cmd->se_sess;
2502
2503         if (!se_sess) {
2504                 se_cmd->se_tfo->release_cmd(se_cmd);
2505                 return 1;
2506         }
2507         return kref_put_spinlock_irqsave(&se_cmd->cmd_kref, target_release_cmd_kref,
2508                         &se_sess->sess_cmd_lock);
2509 }
2510 EXPORT_SYMBOL(target_put_sess_cmd);
2511
2512 /* target_sess_cmd_list_set_waiting - Flag all commands in
2513  *         sess_cmd_list to complete cmd_wait_comp.  Set
2514  *         sess_tearing_down so no more commands are queued.
2515  * @se_sess:    session to flag
2516  */
2517 void target_sess_cmd_list_set_waiting(struct se_session *se_sess)
2518 {
2519         struct se_cmd *se_cmd;
2520         unsigned long flags;
2521
2522         spin_lock_irqsave(&se_sess->sess_cmd_lock, flags);
2523         if (se_sess->sess_tearing_down) {
2524                 spin_unlock_irqrestore(&se_sess->sess_cmd_lock, flags);
2525                 return;
2526         }
2527         se_sess->sess_tearing_down = 1;
2528         list_splice_init(&se_sess->sess_cmd_list, &se_sess->sess_wait_list);
2529
2530         list_for_each_entry(se_cmd, &se_sess->sess_wait_list, se_cmd_list)
2531                 se_cmd->cmd_wait_set = 1;
2532
2533         spin_unlock_irqrestore(&se_sess->sess_cmd_lock, flags);
2534 }
2535 EXPORT_SYMBOL(target_sess_cmd_list_set_waiting);
2536
2537 /* target_wait_for_sess_cmds - Wait for outstanding descriptors
2538  * @se_sess:    session to wait for active I/O
2539  */
2540 void target_wait_for_sess_cmds(struct se_session *se_sess)
2541 {
2542         struct se_cmd *se_cmd, *tmp_cmd;
2543         unsigned long flags;
2544
2545         list_for_each_entry_safe(se_cmd, tmp_cmd,
2546                                 &se_sess->sess_wait_list, se_cmd_list) {
2547                 list_del(&se_cmd->se_cmd_list);
2548
2549                 pr_debug("Waiting for se_cmd: %p t_state: %d, fabric state:"
2550                         " %d\n", se_cmd, se_cmd->t_state,
2551                         se_cmd->se_tfo->get_cmd_state(se_cmd));
2552
2553                 wait_for_completion(&se_cmd->cmd_wait_comp);
2554                 pr_debug("After cmd_wait_comp: se_cmd: %p t_state: %d"
2555                         " fabric state: %d\n", se_cmd, se_cmd->t_state,
2556                         se_cmd->se_tfo->get_cmd_state(se_cmd));
2557
2558                 se_cmd->se_tfo->release_cmd(se_cmd);
2559         }
2560
2561         spin_lock_irqsave(&se_sess->sess_cmd_lock, flags);
2562         WARN_ON(!list_empty(&se_sess->sess_cmd_list));
2563         spin_unlock_irqrestore(&se_sess->sess_cmd_lock, flags);
2564
2565 }
2566 EXPORT_SYMBOL(target_wait_for_sess_cmds);
2567
2568 void transport_clear_lun_ref(struct se_lun *lun)
2569 {
2570         percpu_ref_kill(&lun->lun_ref);
2571         wait_for_completion(&lun->lun_ref_comp);
2572 }
2573
2574 /**
2575  * transport_wait_for_tasks - wait for completion to occur
2576  * @cmd:        command to wait
2577  *
2578  * Called from frontend fabric context to wait for storage engine
2579  * to pause and/or release frontend generated struct se_cmd.
2580  */
2581 bool transport_wait_for_tasks(struct se_cmd *cmd)
2582 {
2583         unsigned long flags;
2584
2585         spin_lock_irqsave(&cmd->t_state_lock, flags);
2586         if (!(cmd->se_cmd_flags & SCF_SE_LUN_CMD) &&
2587             !(cmd->se_cmd_flags & SCF_SCSI_TMR_CDB)) {
2588                 spin_unlock_irqrestore(&cmd->t_state_lock, flags);
2589                 return false;
2590         }
2591
2592         if (!(cmd->se_cmd_flags & SCF_SUPPORTED_SAM_OPCODE) &&
2593             !(cmd->se_cmd_flags & SCF_SCSI_TMR_CDB)) {
2594                 spin_unlock_irqrestore(&cmd->t_state_lock, flags);
2595                 return false;
2596         }
2597
2598         if (!(cmd->transport_state & CMD_T_ACTIVE)) {
2599                 spin_unlock_irqrestore(&cmd->t_state_lock, flags);
2600                 return false;
2601         }
2602
2603         cmd->transport_state |= CMD_T_STOP;
2604
2605         pr_debug("wait_for_tasks: Stopping %p ITT: 0x%08llx i_state: %d, t_state: %d, CMD_T_STOP\n",
2606                 cmd, cmd->tag, cmd->se_tfo->get_cmd_state(cmd), cmd->t_state);
2607
2608         spin_unlock_irqrestore(&cmd->t_state_lock, flags);
2609
2610         wait_for_completion(&cmd->t_transport_stop_comp);
2611
2612         spin_lock_irqsave(&cmd->t_state_lock, flags);
2613         cmd->transport_state &= ~(CMD_T_ACTIVE | CMD_T_STOP);
2614
2615         pr_debug("wait_for_tasks: Stopped wait_for_completion(&cmd->t_transport_stop_comp) for ITT: 0x%08llx\n",
2616                 cmd->tag);
2617
2618         spin_unlock_irqrestore(&cmd->t_state_lock, flags);
2619
2620         return true;
2621 }
2622 EXPORT_SYMBOL(transport_wait_for_tasks);
2623
2624 struct sense_info {
2625         u8 key;
2626         u8 asc;
2627         u8 ascq;
2628         bool add_sector_info;
2629 };
2630
2631 static const struct sense_info sense_info_table[] = {
2632         [TCM_NO_SENSE] = {
2633                 .key = NOT_READY
2634         },
2635         [TCM_NON_EXISTENT_LUN] = {
2636                 .key = ILLEGAL_REQUEST,
2637                 .asc = 0x25 /* LOGICAL UNIT NOT SUPPORTED */
2638         },
2639         [TCM_UNSUPPORTED_SCSI_OPCODE] = {
2640                 .key = ILLEGAL_REQUEST,
2641                 .asc = 0x20, /* INVALID COMMAND OPERATION CODE */
2642         },
2643         [TCM_SECTOR_COUNT_TOO_MANY] = {
2644                 .key = ILLEGAL_REQUEST,
2645                 .asc = 0x20, /* INVALID COMMAND OPERATION CODE */
2646         },
2647         [TCM_UNKNOWN_MODE_PAGE] = {
2648                 .key = ILLEGAL_REQUEST,
2649                 .asc = 0x24, /* INVALID FIELD IN CDB */
2650         },
2651         [TCM_CHECK_CONDITION_ABORT_CMD] = {
2652                 .key = ABORTED_COMMAND,
2653                 .asc = 0x29, /* BUS DEVICE RESET FUNCTION OCCURRED */
2654                 .ascq = 0x03,
2655         },
2656         [TCM_INCORRECT_AMOUNT_OF_DATA] = {
2657                 .key = ABORTED_COMMAND,
2658                 .asc = 0x0c, /* WRITE ERROR */
2659                 .ascq = 0x0d, /* NOT ENOUGH UNSOLICITED DATA */
2660         },
2661         [TCM_INVALID_CDB_FIELD] = {
2662                 .key = ILLEGAL_REQUEST,
2663                 .asc = 0x24, /* INVALID FIELD IN CDB */
2664         },
2665         [TCM_INVALID_PARAMETER_LIST] = {
2666                 .key = ILLEGAL_REQUEST,
2667                 .asc = 0x26, /* INVALID FIELD IN PARAMETER LIST */
2668         },
2669         [TCM_PARAMETER_LIST_LENGTH_ERROR] = {
2670                 .key = ILLEGAL_REQUEST,
2671                 .asc = 0x1a, /* PARAMETER LIST LENGTH ERROR */
2672         },
2673         [TCM_UNEXPECTED_UNSOLICITED_DATA] = {
2674                 .key = ILLEGAL_REQUEST,
2675                 .asc = 0x0c, /* WRITE ERROR */
2676                 .ascq = 0x0c, /* UNEXPECTED_UNSOLICITED_DATA */
2677         },
2678         [TCM_SERVICE_CRC_ERROR] = {
2679                 .key = ABORTED_COMMAND,
2680                 .asc = 0x47, /* PROTOCOL SERVICE CRC ERROR */
2681                 .ascq = 0x05, /* N/A */
2682         },
2683         [TCM_SNACK_REJECTED] = {
2684                 .key = ABORTED_COMMAND,
2685                 .asc = 0x11, /* READ ERROR */
2686                 .ascq = 0x13, /* FAILED RETRANSMISSION REQUEST */
2687         },
2688         [TCM_WRITE_PROTECTED] = {
2689                 .key = DATA_PROTECT,
2690                 .asc = 0x27, /* WRITE PROTECTED */
2691         },
2692         [TCM_ADDRESS_OUT_OF_RANGE] = {
2693                 .key = ILLEGAL_REQUEST,
2694                 .asc = 0x21, /* LOGICAL BLOCK ADDRESS OUT OF RANGE */
2695         },
2696         [TCM_CHECK_CONDITION_UNIT_ATTENTION] = {
2697                 .key = UNIT_ATTENTION,
2698         },
2699         [TCM_CHECK_CONDITION_NOT_READY] = {
2700                 .key = NOT_READY,
2701         },
2702         [TCM_MISCOMPARE_VERIFY] = {
2703                 .key = MISCOMPARE,
2704                 .asc = 0x1d, /* MISCOMPARE DURING VERIFY OPERATION */
2705                 .ascq = 0x00,
2706         },
2707         [TCM_LOGICAL_BLOCK_GUARD_CHECK_FAILED] = {
2708                 .key = ABORTED_COMMAND,
2709                 .asc = 0x10,
2710                 .ascq = 0x01, /* LOGICAL BLOCK GUARD CHECK FAILED */
2711                 .add_sector_info = true,
2712         },
2713         [TCM_LOGICAL_BLOCK_APP_TAG_CHECK_FAILED] = {
2714                 .key = ABORTED_COMMAND,
2715                 .asc = 0x10,
2716                 .ascq = 0x02, /* LOGICAL BLOCK APPLICATION TAG CHECK FAILED */
2717                 .add_sector_info = true,
2718         },
2719         [TCM_LOGICAL_BLOCK_REF_TAG_CHECK_FAILED] = {
2720                 .key = ABORTED_COMMAND,
2721                 .asc = 0x10,
2722                 .ascq = 0x03, /* LOGICAL BLOCK REFERENCE TAG CHECK FAILED */
2723                 .add_sector_info = true,
2724         },
2725         [TCM_LOGICAL_UNIT_COMMUNICATION_FAILURE] = {
2726                 /*
2727                  * Returning ILLEGAL REQUEST would cause immediate IO errors on
2728                  * Solaris initiators.  Returning NOT READY instead means the
2729                  * operations will be retried a finite number of times and we
2730                  * can survive intermittent errors.
2731                  */
2732                 .key = NOT_READY,
2733                 .asc = 0x08, /* LOGICAL UNIT COMMUNICATION FAILURE */
2734         },
2735 };
2736
2737 static int translate_sense_reason(struct se_cmd *cmd, sense_reason_t reason)
2738 {
2739         const struct sense_info *si;
2740         u8 *buffer = cmd->sense_buffer;
2741         int r = (__force int)reason;
2742         u8 asc, ascq;
2743         bool desc_format = target_sense_desc_format(cmd->se_dev);
2744
2745         if (r < ARRAY_SIZE(sense_info_table) && sense_info_table[r].key)
2746                 si = &sense_info_table[r];
2747         else
2748                 si = &sense_info_table[(__force int)
2749                                        TCM_LOGICAL_UNIT_COMMUNICATION_FAILURE];
2750
2751         if (reason == TCM_CHECK_CONDITION_UNIT_ATTENTION) {
2752                 core_scsi3_ua_for_check_condition(cmd, &asc, &ascq);
2753                 WARN_ON_ONCE(asc == 0);
2754         } else if (si->asc == 0) {
2755                 WARN_ON_ONCE(cmd->scsi_asc == 0);
2756                 asc = cmd->scsi_asc;
2757                 ascq = cmd->scsi_ascq;
2758         } else {
2759                 asc = si->asc;
2760                 ascq = si->ascq;
2761         }
2762
2763         scsi_build_sense_buffer(desc_format, buffer, si->key, asc, ascq);
2764         if (si->add_sector_info)
2765                 return scsi_set_sense_information(buffer,
2766                                                   cmd->scsi_sense_length,
2767                                                   cmd->bad_sector);
2768
2769         return 0;
2770 }
2771
2772 int
2773 transport_send_check_condition_and_sense(struct se_cmd *cmd,
2774                 sense_reason_t reason, int from_transport)
2775 {
2776         unsigned long flags;
2777
2778         spin_lock_irqsave(&cmd->t_state_lock, flags);
2779         if (cmd->se_cmd_flags & SCF_SENT_CHECK_CONDITION) {
2780                 spin_unlock_irqrestore(&cmd->t_state_lock, flags);
2781                 return 0;
2782         }
2783         cmd->se_cmd_flags |= SCF_SENT_CHECK_CONDITION;
2784         spin_unlock_irqrestore(&cmd->t_state_lock, flags);
2785
2786         if (!from_transport) {
2787                 int rc;
2788
2789                 cmd->se_cmd_flags |= SCF_EMULATED_TASK_SENSE;
2790                 cmd->scsi_status = SAM_STAT_CHECK_CONDITION;
2791                 cmd->scsi_sense_length  = TRANSPORT_SENSE_BUFFER;
2792                 rc = translate_sense_reason(cmd, reason);
2793                 if (rc)
2794                         return rc;
2795         }
2796
2797         trace_target_cmd_complete(cmd);
2798         return cmd->se_tfo->queue_status(cmd);
2799 }
2800 EXPORT_SYMBOL(transport_send_check_condition_and_sense);
2801
2802 int transport_check_aborted_status(struct se_cmd *cmd, int send_status)
2803 {
2804         if (!(cmd->transport_state & CMD_T_ABORTED))
2805                 return 0;
2806
2807         /*
2808          * If cmd has been aborted but either no status is to be sent or it has
2809          * already been sent, just return
2810          */
2811         if (!send_status || !(cmd->se_cmd_flags & SCF_SEND_DELAYED_TAS))
2812                 return 1;
2813
2814         pr_debug("Sending delayed SAM_STAT_TASK_ABORTED status for CDB: 0x%02x ITT: 0x%08llx\n",
2815                  cmd->t_task_cdb[0], cmd->tag);
2816
2817         cmd->se_cmd_flags &= ~SCF_SEND_DELAYED_TAS;
2818         cmd->scsi_status = SAM_STAT_TASK_ABORTED;
2819         trace_target_cmd_complete(cmd);
2820         cmd->se_tfo->queue_status(cmd);
2821
2822         return 1;
2823 }
2824 EXPORT_SYMBOL(transport_check_aborted_status);
2825
2826 void transport_send_task_abort(struct se_cmd *cmd)
2827 {
2828         unsigned long flags;
2829
2830         spin_lock_irqsave(&cmd->t_state_lock, flags);
2831         if (cmd->se_cmd_flags & (SCF_SENT_CHECK_CONDITION)) {
2832                 spin_unlock_irqrestore(&cmd->t_state_lock, flags);
2833                 return;
2834         }
2835         spin_unlock_irqrestore(&cmd->t_state_lock, flags);
2836
2837         /*
2838          * If there are still expected incoming fabric WRITEs, we wait
2839          * until until they have completed before sending a TASK_ABORTED
2840          * response.  This response with TASK_ABORTED status will be
2841          * queued back to fabric module by transport_check_aborted_status().
2842          */
2843         if (cmd->data_direction == DMA_TO_DEVICE) {
2844                 if (cmd->se_tfo->write_pending_status(cmd) != 0) {
2845                         cmd->transport_state |= CMD_T_ABORTED;
2846                         cmd->se_cmd_flags |= SCF_SEND_DELAYED_TAS;
2847                         return;
2848                 }
2849         }
2850         cmd->scsi_status = SAM_STAT_TASK_ABORTED;
2851
2852         transport_lun_remove_cmd(cmd);
2853
2854         pr_debug("Setting SAM_STAT_TASK_ABORTED status for CDB: 0x%02x, ITT: 0x%08llx\n",
2855                  cmd->t_task_cdb[0], cmd->tag);
2856
2857         trace_target_cmd_complete(cmd);
2858         cmd->se_tfo->queue_status(cmd);
2859 }
2860
2861 static void target_tmr_work(struct work_struct *work)
2862 {
2863         struct se_cmd *cmd = container_of(work, struct se_cmd, work);
2864         struct se_device *dev = cmd->se_dev;
2865         struct se_tmr_req *tmr = cmd->se_tmr_req;
2866         int ret;
2867
2868         switch (tmr->function) {
2869         case TMR_ABORT_TASK:
2870                 core_tmr_abort_task(dev, tmr, cmd->se_sess);
2871                 break;
2872         case TMR_ABORT_TASK_SET:
2873         case TMR_CLEAR_ACA:
2874         case TMR_CLEAR_TASK_SET:
2875                 tmr->response = TMR_TASK_MGMT_FUNCTION_NOT_SUPPORTED;
2876                 break;
2877         case TMR_LUN_RESET:
2878                 ret = core_tmr_lun_reset(dev, tmr, NULL, NULL);
2879                 tmr->response = (!ret) ? TMR_FUNCTION_COMPLETE :
2880                                          TMR_FUNCTION_REJECTED;
2881                 if (tmr->response == TMR_FUNCTION_COMPLETE) {
2882                         target_ua_allocate_lun(cmd->se_sess->se_node_acl,
2883                                                cmd->orig_fe_lun, 0x29,
2884                                                ASCQ_29H_BUS_DEVICE_RESET_FUNCTION_OCCURRED);
2885                 }
2886                 break;
2887         case TMR_TARGET_WARM_RESET:
2888                 tmr->response = TMR_FUNCTION_REJECTED;
2889                 break;
2890         case TMR_TARGET_COLD_RESET:
2891                 tmr->response = TMR_FUNCTION_REJECTED;
2892                 break;
2893         default:
2894                 pr_err("Uknown TMR function: 0x%02x.\n",
2895                                 tmr->function);
2896                 tmr->response = TMR_FUNCTION_REJECTED;
2897                 break;
2898         }
2899
2900         cmd->t_state = TRANSPORT_ISTATE_PROCESSING;
2901         cmd->se_tfo->queue_tm_rsp(cmd);
2902
2903         transport_cmd_check_stop_to_fabric(cmd);
2904 }
2905
2906 int transport_generic_handle_tmr(
2907         struct se_cmd *cmd)
2908 {
2909         unsigned long flags;
2910
2911         spin_lock_irqsave(&cmd->t_state_lock, flags);
2912         cmd->transport_state |= CMD_T_ACTIVE;
2913         spin_unlock_irqrestore(&cmd->t_state_lock, flags);
2914
2915         INIT_WORK(&cmd->work, target_tmr_work);
2916         queue_work(cmd->se_dev->tmr_wq, &cmd->work);
2917         return 0;
2918 }
2919 EXPORT_SYMBOL(transport_generic_handle_tmr);
2920
2921 bool
2922 target_check_wce(struct se_device *dev)
2923 {
2924         bool wce = false;
2925
2926         if (dev->transport->get_write_cache)
2927                 wce = dev->transport->get_write_cache(dev);
2928         else if (dev->dev_attrib.emulate_write_cache > 0)
2929                 wce = true;
2930
2931         return wce;
2932 }
2933
2934 bool
2935 target_check_fua(struct se_device *dev)
2936 {
2937         return target_check_wce(dev) && dev->dev_attrib.emulate_fua_write > 0;
2938 }