drivers/target/target_core_tmr.c

   1 /*******************************************************************************
   2  * Filename:  target_core_tmr.c
   3  *
   4  * This file contains SPC-3 task management infrastructure
   5  *
   6  * (c) Copyright 2009-2013 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/slab.h>
  27 #include <linux/spinlock.h>
  28 #include <linux/list.h>
  29 #include <linux/export.h>
  30
  31 #include <target/target_core_base.h>
  32 #include <target/target_core_backend.h>
  33 #include <target/target_core_fabric.h>
  34
  35 #include "target_core_internal.h"
  36 #include "target_core_alua.h"
  37 #include "target_core_pr.h"
  38
  39 int core_tmr_alloc_req(
  40         struct se_cmd *se_cmd,
  41         void *fabric_tmr_ptr,
  42         u8 function,
  43         gfp_t gfp_flags)
  44 {
  45         struct se_tmr_req *tmr;
  46
  47         tmr = kzalloc(sizeof(struct se_tmr_req), gfp_flags);
  48         if (!tmr) {
  49                 pr_err("Unable to allocate struct se_tmr_req\n");
  50                 return -ENOMEM;
  51         }
  52
  53         se_cmd->se_cmd_flags |= SCF_SCSI_TMR_CDB;
  54         se_cmd->se_tmr_req = tmr;
  55         tmr->task_cmd = se_cmd;
  56         tmr->fabric_tmr_ptr = fabric_tmr_ptr;
  57         tmr->function = function;
  58         INIT_LIST_HEAD(&tmr->tmr_list);
  59
  60         return 0;
  61 }
  62 EXPORT_SYMBOL(core_tmr_alloc_req);
  63
  64 void core_tmr_release_req(struct se_tmr_req *tmr)
  65 {
  66         struct se_device *dev = tmr->tmr_dev;
  67         unsigned long flags;
  68
  69         if (dev) {
  70                 spin_lock_irqsave(&dev->se_tmr_lock, flags);
  71                 list_del_init(&tmr->tmr_list);
  72                 spin_unlock_irqrestore(&dev->se_tmr_lock, flags);
  73         }
  74
  75         kfree(tmr);
  76 }
  77
  78 static int core_tmr_handle_tas_abort(struct se_cmd *cmd, int tas)
  79 {
  80         unsigned long flags;
  81         bool remove = true, send_tas;
  82         /*
  83          * TASK ABORTED status (TAS) bit support
  84          */
  85         spin_lock_irqsave(&cmd->t_state_lock, flags);
  86         send_tas = (cmd->transport_state & CMD_T_TAS);
  87         spin_unlock_irqrestore(&cmd->t_state_lock, flags);
  88
  89         if (send_tas) {
  90                 remove = false;
  91                 transport_send_task_abort(cmd);
  92         }
  93
  94         return transport_cmd_finish_abort(cmd, remove);
  95 }
  96
  97 static int target_check_cdb_and_preempt(struct list_head *list,
  98                 struct se_cmd *cmd)
  99 {
 100         struct t10_pr_registration *reg;
 101
 102         if (!list)
 103                 return 0;
 104         list_for_each_entry(reg, list, pr_reg_abort_list) {
 105                 if (reg->pr_res_key == cmd->pr_res_key)
 106                         return 0;
 107         }
 108
 109         return 1;
 110 }
 111
 112 static bool __target_check_io_state(struct se_cmd *se_cmd,
 113                                     struct se_session *tmr_sess, int tas)
 114 {
 115         struct se_session *sess = se_cmd->se_sess;
 116
 117         assert_spin_locked(&sess->sess_cmd_lock);
 118         WARN_ON_ONCE(!irqs_disabled());
 119         /*
 120          * If command already reached CMD_T_COMPLETE state within
 121          * target_complete_cmd() or CMD_T_FABRIC_STOP due to shutdown,
 122          * this se_cmd has been passed to fabric driver and will
 123          * not be aborted.
 124          *
 125          * Otherwise, obtain a local se_cmd->cmd_kref now for TMR
 126          * ABORT_TASK + LUN_RESET for CMD_T_ABORTED processing as
 127          * long as se_cmd->cmd_kref is still active unless zero.
 128          */
 129         spin_lock(&se_cmd->t_state_lock);
 130         if (se_cmd->transport_state & (CMD_T_COMPLETE | CMD_T_FABRIC_STOP)) {
 131                 pr_debug("Attempted to abort io tag: %llu already complete or"
 132                         " fabric stop, skipping\n", se_cmd->tag);
 133                 spin_unlock(&se_cmd->t_state_lock);
 134                 return false;
 135         }
 136         if (se_cmd->transport_state & CMD_T_PRE_EXECUTE) {
 137                 if (se_cmd->scsi_status) {
 138                         pr_debug("Attempted to abort io tag: %llu early failure"
 139                                  " status: 0x%02x\n", se_cmd->tag,
 140                                  se_cmd->scsi_status);
 141                         spin_unlock(&se_cmd->t_state_lock);
 142                         return false;
 143                 }
 144         }
 145         if (sess->sess_tearing_down || se_cmd->cmd_wait_set) {
 146                 pr_debug("Attempted to abort io tag: %llu already shutdown,"
 147                         " skipping\n", se_cmd->tag);
 148                 spin_unlock(&se_cmd->t_state_lock);
 149                 return false;
 150         }
 151         se_cmd->transport_state |= CMD_T_ABORTED;
 152
 153         if ((tmr_sess != se_cmd->se_sess) && tas)
 154                 se_cmd->transport_state |= CMD_T_TAS;
 155
 156         spin_unlock(&se_cmd->t_state_lock);
 157
 158         return kref_get_unless_zero(&se_cmd->cmd_kref);
 159 }
 160
 161 void core_tmr_abort_task(
 162         struct se_device *dev,
 163         struct se_tmr_req *tmr,
 164         struct se_session *se_sess)
 165 {
 166         struct se_cmd *se_cmd;
 167         unsigned long flags;
 168         u64 ref_tag;
 169
 170         spin_lock_irqsave(&se_sess->sess_cmd_lock, flags);
 171         list_for_each_entry(se_cmd, &se_sess->sess_cmd_list, se_cmd_list) {
 172
 173                 if (dev != se_cmd->se_dev)
 174                         continue;
 175
 176                 /* skip task management functions, including tmr->task_cmd */
 177                 if (se_cmd->se_cmd_flags & SCF_SCSI_TMR_CDB)
 178                         continue;
 179
 180                 ref_tag = se_cmd->tag;
 181                 if (tmr->ref_task_tag != ref_tag)
 182                         continue;
 183
 184                 printk("ABORT_TASK: Found referenced %s task_tag: %llu\n",
 185                         se_cmd->se_tfo->get_fabric_name(), ref_tag);
 186
 187                 if (!__target_check_io_state(se_cmd, se_sess, 0)) {
 188                         spin_unlock_irqrestore(&se_sess->sess_cmd_lock, flags);
 189                         goto out;
 190                 }
 191                 list_del_init(&se_cmd->se_cmd_list);
 192                 spin_unlock_irqrestore(&se_sess->sess_cmd_lock, flags);
 193
 194                 cancel_work_sync(&se_cmd->work);
 195                 transport_wait_for_tasks(se_cmd);
 196
 197                 if (!transport_cmd_finish_abort(se_cmd, true))
 198                         target_put_sess_cmd(se_cmd);
 199
 200                 printk("ABORT_TASK: Sending TMR_FUNCTION_COMPLETE for"
 201                                 " ref_tag: %llu\n", ref_tag);
 202                 tmr->response = TMR_FUNCTION_COMPLETE;
 203                 return;
 204         }
 205         spin_unlock_irqrestore(&se_sess->sess_cmd_lock, flags);
 206
 207 out:
 208         printk("ABORT_TASK: Sending TMR_TASK_DOES_NOT_EXIST for ref_tag: %lld\n",
 209                         tmr->ref_task_tag);
 210         tmr->response = TMR_TASK_DOES_NOT_EXIST;
 211 }
 212
 213 static void core_tmr_drain_tmr_list(
 214         struct se_device *dev,
 215         struct se_tmr_req *tmr,
 216         struct list_head *preempt_and_abort_list)
 217 {
 218         LIST_HEAD(drain_tmr_list);
 219         struct se_session *sess;
 220         struct se_tmr_req *tmr_p, *tmr_pp;
 221         struct se_cmd *cmd;
 222         unsigned long flags;
 223         bool rc;
 224         /*
 225          * Release all pending and outgoing TMRs aside from the received
 226          * LUN_RESET tmr..
 227          */
 228         spin_lock_irqsave(&dev->se_tmr_lock, flags);
 229         list_for_each_entry_safe(tmr_p, tmr_pp, &dev->dev_tmr_list, tmr_list) {
 230                 /*
 231                  * Allow the received TMR to return with FUNCTION_COMPLETE.
 232                  */
 233                 if (tmr_p == tmr)
 234                         continue;
 235
 236                 cmd = tmr_p->task_cmd;
 237                 if (!cmd) {
 238                         pr_err("Unable to locate struct se_cmd for TMR\n");
 239                         continue;
 240                 }
 241                 /*
 242                  * If this function was called with a valid pr_res_key
 243                  * parameter (eg: for PROUT PREEMPT_AND_ABORT service action
 244                  * skip non registration key matching TMRs.
 245                  */
 246                 if (target_check_cdb_and_preempt(preempt_and_abort_list, cmd))
 247                         continue;
 248
 249                 sess = cmd->se_sess;
 250                 if (WARN_ON_ONCE(!sess))
 251                         continue;
 252
 253                 spin_lock(&sess->sess_cmd_lock);
 254                 spin_lock(&cmd->t_state_lock);
 255                 if (!(cmd->transport_state & CMD_T_ACTIVE) ||
 256                      (cmd->transport_state & CMD_T_FABRIC_STOP)) {
 257                         spin_unlock(&cmd->t_state_lock);
 258                         spin_unlock(&sess->sess_cmd_lock);
 259                         continue;
 260                 }
 261                 if (cmd->t_state == TRANSPORT_ISTATE_PROCESSING) {
 262                         spin_unlock(&cmd->t_state_lock);
 263                         spin_unlock(&sess->sess_cmd_lock);
 264                         continue;
 265                 }
 266                 if (sess->sess_tearing_down || cmd->cmd_wait_set) {
 267                         spin_unlock(&cmd->t_state_lock);
 268                         spin_unlock(&sess->sess_cmd_lock);
 269                         continue;
 270                 }
 271                 cmd->transport_state |= CMD_T_ABORTED;
 272                 spin_unlock(&cmd->t_state_lock);
 273
 274                 rc = kref_get_unless_zero(&cmd->cmd_kref);
 275                 if (!rc) {
 276                         printk("LUN_RESET TMR: non-zero kref_get_unless_zero\n");
 277                         spin_unlock(&sess->sess_cmd_lock);
 278                         continue;
 279                 }
 280                 spin_unlock(&sess->sess_cmd_lock);
 281
 282                 list_move_tail(&tmr_p->tmr_list, &drain_tmr_list);
 283         }
 284         spin_unlock_irqrestore(&dev->se_tmr_lock, flags);
 285
 286         list_for_each_entry_safe(tmr_p, tmr_pp, &drain_tmr_list, tmr_list) {
 287                 list_del_init(&tmr_p->tmr_list);
 288                 cmd = tmr_p->task_cmd;
 289
 290                 pr_debug("LUN_RESET: %s releasing TMR %p Function: 0x%02x,"
 291                         " Response: 0x%02x, t_state: %d\n",
 292                         (preempt_and_abort_list) ? "Preempt" : "", tmr_p,
 293                         tmr_p->function, tmr_p->response, cmd->t_state);
 294
 295                 cancel_work_sync(&cmd->work);
 296                 transport_wait_for_tasks(cmd);
 297
 298                 if (!transport_cmd_finish_abort(cmd, 1))
 299                         target_put_sess_cmd(cmd);
 300         }
 301 }
 302
 303 static void core_tmr_drain_state_list(
 304         struct se_device *dev,
 305         struct se_cmd *prout_cmd,
 306         struct se_session *tmr_sess,
 307         int tas,
 308         struct list_head *preempt_and_abort_list)
 309 {
 310         LIST_HEAD(drain_task_list);
 311         struct se_session *sess;
 312         struct se_cmd *cmd, *next;
 313         unsigned long flags;
 314         int rc;
 315
 316         /*
 317          * Complete outstanding commands with TASK_ABORTED SAM status.
 318          *
 319          * This is following sam4r17, section 5.6 Aborting commands, Table 38
 320          * for TMR LUN_RESET:
 321          *
 322          * a) "Yes" indicates that each command that is aborted on an I_T nexus
 323          * other than the one that caused the SCSI device condition is
 324          * completed with TASK ABORTED status, if the TAS bit is set to one in
 325          * the Control mode page (see SPC-4). "No" indicates that no status is
 326          * returned for aborted commands.
 327          *
 328          * d) If the logical unit reset is caused by a particular I_T nexus
 329          * (e.g., by a LOGICAL UNIT RESET task management function), then "yes"
 330          * (TASK_ABORTED status) applies.
 331          *
 332          * Otherwise (e.g., if triggered by a hard reset), "no"
 333          * (no TASK_ABORTED SAM status) applies.
 334          *
 335          * Note that this seems to be independent of TAS (Task Aborted Status)
 336          * in the Control Mode Page.
 337          */
 338         spin_lock_irqsave(&dev->execute_task_lock, flags);
 339         list_for_each_entry_safe(cmd, next, &dev->state_list, state_list) {
 340                 /*
 341                  * For PREEMPT_AND_ABORT usage, only process commands
 342                  * with a matching reservation key.
 343                  */
 344                 if (target_check_cdb_and_preempt(preempt_and_abort_list, cmd))
 345                         continue;
 346
 347                 /*
 348                  * Not aborting PROUT PREEMPT_AND_ABORT CDB..
 349                  */
 350                 if (prout_cmd == cmd)
 351                         continue;
 352
 353                 sess = cmd->se_sess;
 354                 if (WARN_ON_ONCE(!sess))
 355                         continue;
 356
 357                 spin_lock(&sess->sess_cmd_lock);
 358                 rc = __target_check_io_state(cmd, tmr_sess, tas);
 359                 spin_unlock(&sess->sess_cmd_lock);
 360                 if (!rc)
 361                         continue;
 362
 363                 list_move_tail(&cmd->state_list, &drain_task_list);
 364                 cmd->state_active = false;
 365         }
 366         spin_unlock_irqrestore(&dev->execute_task_lock, flags);
 367
 368         while (!list_empty(&drain_task_list)) {
 369                 cmd = list_entry(drain_task_list.next, struct se_cmd, state_list);
 370                 list_del_init(&cmd->state_list);
 371
 372                 pr_debug("LUN_RESET: %s cmd: %p"
 373                         " ITT/CmdSN: 0x%08llx/0x%08x, i_state: %d, t_state: %d"
 374                         "cdb: 0x%02x\n",
 375                         (preempt_and_abort_list) ? "Preempt" : "", cmd,
 376                         cmd->tag, 0,
 377                         cmd->se_tfo->get_cmd_state(cmd), cmd->t_state,
 378                         cmd->t_task_cdb[0]);
 379                 pr_debug("LUN_RESET: ITT[0x%08llx] - pr_res_key: 0x%016Lx"
 380                         " -- CMD_T_ACTIVE: %d"
 381                         " CMD_T_STOP: %d CMD_T_SENT: %d\n",
 382                         cmd->tag, cmd->pr_res_key,
 383                         (cmd->transport_state & CMD_T_ACTIVE) != 0,
 384                         (cmd->transport_state & CMD_T_STOP) != 0,
 385                         (cmd->transport_state & CMD_T_SENT) != 0);
 386
 387                 /*
 388                  * If the command may be queued onto a workqueue cancel it now.
 389                  *
 390                  * This is equivalent to removal from the execute queue in the
 391                  * loop above, but we do it down here given that
 392                  * cancel_work_sync may block.
 393                  */
 394                 cancel_work_sync(&cmd->work);
 395                 transport_wait_for_tasks(cmd);
 396
 397                 if (!core_tmr_handle_tas_abort(cmd, tas))
 398                         target_put_sess_cmd(cmd);
 399         }
 400 }
 401
 402 int core_tmr_lun_reset(
 403         struct se_device *dev,
 404         struct se_tmr_req *tmr,
 405         struct list_head *preempt_and_abort_list,
 406         struct se_cmd *prout_cmd)
 407 {
 408         struct se_node_acl *tmr_nacl = NULL;
 409         struct se_portal_group *tmr_tpg = NULL;
 410         struct se_session *tmr_sess = NULL;
 411         int tas;
 412         /*
 413          * TASK_ABORTED status bit, this is configurable via ConfigFS
 414          * struct se_device attributes.  spc4r17 section 7.4.6 Control mode page
 415          *
 416          * A task aborted status (TAS) bit set to zero specifies that aborted
 417          * tasks shall be terminated by the device server without any response
 418          * to the application client. A TAS bit set to one specifies that tasks
 419          * aborted by the actions of an I_T nexus other than the I_T nexus on
 420          * which the command was received shall be completed with TASK ABORTED
 421          * status (see SAM-4).
 422          */
 423         tas = dev->dev_attrib.emulate_tas;
 424         /*
 425          * Determine if this se_tmr is coming from a $FABRIC_MOD
 426          * or struct se_device passthrough..
 427          */
 428         if (tmr && tmr->task_cmd && tmr->task_cmd->se_sess) {
 429                 tmr_sess = tmr->task_cmd->se_sess;
 430                 tmr_nacl = tmr_sess->se_node_acl;
 431                 tmr_tpg = tmr_sess->se_tpg;
 432                 if (tmr_nacl && tmr_tpg) {
 433                         pr_debug("LUN_RESET: TMR caller fabric: %s"
 434                                 " initiator port %s\n",
 435                                 tmr_tpg->se_tpg_tfo->get_fabric_name(),
 436                                 tmr_nacl->initiatorname);
 437                 }
 438         }
 439         pr_debug("LUN_RESET: %s starting for [%s], tas: %d\n",
 440                 (preempt_and_abort_list) ? "Preempt" : "TMR",
 441                 dev->transport->name, tas);
 442
 443         core_tmr_drain_tmr_list(dev, tmr, preempt_and_abort_list);
 444         core_tmr_drain_state_list(dev, prout_cmd, tmr_sess, tas,
 445                                 preempt_and_abort_list);
 446
 447         /*
 448          * Clear any legacy SPC-2 reservation when called during
 449          * LOGICAL UNIT RESET
 450          */
 451         if (!preempt_and_abort_list &&
 452              (dev->dev_reservation_flags & DRF_SPC2_RESERVATIONS)) {
 453                 spin_lock(&dev->dev_reservation_lock);
 454                 dev->dev_reserved_node_acl = NULL;
 455                 dev->dev_reservation_flags &= ~DRF_SPC2_RESERVATIONS;
 456                 spin_unlock(&dev->dev_reservation_lock);
 457                 pr_debug("LUN_RESET: SCSI-2 Released reservation\n");
 458         }
 459
 460         atomic_long_inc(&dev->num_resets);
 461
 462         pr_debug("LUN_RESET: %s for [%s] Complete\n",
 463                         (preempt_and_abort_list) ? "Preempt" : "TMR",
 464                         dev->transport->name);
 465         return 0;
 466 }
 467