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 void 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         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 (sess->sess_tearing_down || se_cmd->cmd_wait_set) {
 137                 pr_debug("Attempted to abort io tag: %llu already shutdown,"
 138                         " skipping\n", se_cmd->tag);
 139                 spin_unlock(&se_cmd->t_state_lock);
 140                 return false;
 141         }
 142         se_cmd->transport_state |= CMD_T_ABORTED;
 143
 144         if ((tmr_sess != se_cmd->se_sess) && tas)
 145                 se_cmd->transport_state |= CMD_T_TAS;
 146
 147         spin_unlock(&se_cmd->t_state_lock);
 148
 149         return kref_get_unless_zero(&se_cmd->cmd_kref);
 150 }
 151
 152 void core_tmr_abort_task(
 153         struct se_device *dev,
 154         struct se_tmr_req *tmr,
 155         struct se_session *se_sess)
 156 {
 157         struct se_cmd *se_cmd;
 158         unsigned long flags;
 159         u64 ref_tag;
 160
 161         spin_lock_irqsave(&se_sess->sess_cmd_lock, flags);
 162         list_for_each_entry(se_cmd, &se_sess->sess_cmd_list, se_cmd_list) {
 163
 164                 if (dev != se_cmd->se_dev)
 165                         continue;
 166
 167                 /* skip task management functions, including tmr->task_cmd */
 168                 if (se_cmd->se_cmd_flags & SCF_SCSI_TMR_CDB)
 169                         continue;
 170
 171                 ref_tag = se_cmd->tag;
 172                 if (tmr->ref_task_tag != ref_tag)
 173                         continue;
 174
 175                 printk("ABORT_TASK: Found referenced %s task_tag: %llu\n",
 176                         se_cmd->se_tfo->get_fabric_name(), ref_tag);
 177
 178                 if (!__target_check_io_state(se_cmd, se_sess, 0)) {
 179                         spin_unlock_irqrestore(&se_sess->sess_cmd_lock, flags);
 180                         goto out;
 181                 }
 182                 list_del_init(&se_cmd->se_cmd_list);
 183                 spin_unlock_irqrestore(&se_sess->sess_cmd_lock, flags);
 184
 185                 cancel_work_sync(&se_cmd->work);
 186                 transport_wait_for_tasks(se_cmd);
 187
 188                 transport_cmd_finish_abort(se_cmd, true);
 189                 target_put_sess_cmd(se_cmd);
 190
 191                 printk("ABORT_TASK: Sending TMR_FUNCTION_COMPLETE for"
 192                                 " ref_tag: %llu\n", ref_tag);
 193                 tmr->response = TMR_FUNCTION_COMPLETE;
 194                 return;
 195         }
 196         spin_unlock_irqrestore(&se_sess->sess_cmd_lock, flags);
 197
 198 out:
 199         printk("ABORT_TASK: Sending TMR_TASK_DOES_NOT_EXIST for ref_tag: %lld\n",
 200                         tmr->ref_task_tag);
 201         tmr->response = TMR_TASK_DOES_NOT_EXIST;
 202 }
 203
 204 static void core_tmr_drain_tmr_list(
 205         struct se_device *dev,
 206         struct se_tmr_req *tmr,
 207         struct list_head *preempt_and_abort_list)
 208 {
 209         LIST_HEAD(drain_tmr_list);
 210         struct se_session *sess;
 211         struct se_tmr_req *tmr_p, *tmr_pp;
 212         struct se_cmd *cmd;
 213         unsigned long flags;
 214         bool rc;
 215         /*
 216          * Release all pending and outgoing TMRs aside from the received
 217          * LUN_RESET tmr..
 218          */
 219         spin_lock_irqsave(&dev->se_tmr_lock, flags);
 220         list_for_each_entry_safe(tmr_p, tmr_pp, &dev->dev_tmr_list, tmr_list) {
 221                 /*
 222                  * Allow the received TMR to return with FUNCTION_COMPLETE.
 223                  */
 224                 if (tmr_p == tmr)
 225                         continue;
 226
 227                 cmd = tmr_p->task_cmd;
 228                 if (!cmd) {
 229                         pr_err("Unable to locate struct se_cmd for TMR\n");
 230                         continue;
 231                 }
 232                 /*
 233                  * If this function was called with a valid pr_res_key
 234                  * parameter (eg: for PROUT PREEMPT_AND_ABORT service action
 235                  * skip non regisration key matching TMRs.
 236                  */
 237                 if (target_check_cdb_and_preempt(preempt_and_abort_list, cmd))
 238                         continue;
 239
 240                 sess = cmd->se_sess;
 241                 if (WARN_ON_ONCE(!sess))
 242                         continue;
 243
 244                 spin_lock(&sess->sess_cmd_lock);
 245                 spin_lock(&cmd->t_state_lock);
 246                 if (!(cmd->transport_state & CMD_T_ACTIVE) ||
 247                      (cmd->transport_state & CMD_T_FABRIC_STOP)) {
 248                         spin_unlock(&cmd->t_state_lock);
 249                         spin_unlock(&sess->sess_cmd_lock);
 250                         continue;
 251                 }
 252                 if (cmd->t_state == TRANSPORT_ISTATE_PROCESSING) {
 253                         spin_unlock(&cmd->t_state_lock);
 254                         spin_unlock(&sess->sess_cmd_lock);
 255                         continue;
 256                 }
 257                 if (sess->sess_tearing_down || cmd->cmd_wait_set) {
 258                         spin_unlock(&cmd->t_state_lock);
 259                         spin_unlock(&sess->sess_cmd_lock);
 260                         continue;
 261                 }
 262                 cmd->transport_state |= CMD_T_ABORTED;
 263                 spin_unlock(&cmd->t_state_lock);
 264
 265                 rc = kref_get_unless_zero(&cmd->cmd_kref);
 266                 if (!rc) {
 267                         printk("LUN_RESET TMR: non-zero kref_get_unless_zero\n");
 268                         spin_unlock(&sess->sess_cmd_lock);
 269                         continue;
 270                 }
 271                 spin_unlock(&sess->sess_cmd_lock);
 272
 273                 list_move_tail(&tmr_p->tmr_list, &drain_tmr_list);
 274         }
 275         spin_unlock_irqrestore(&dev->se_tmr_lock, flags);
 276
 277         list_for_each_entry_safe(tmr_p, tmr_pp, &drain_tmr_list, tmr_list) {
 278                 list_del_init(&tmr_p->tmr_list);
 279                 cmd = tmr_p->task_cmd;
 280
 281                 pr_debug("LUN_RESET: %s releasing TMR %p Function: 0x%02x,"
 282                         " Response: 0x%02x, t_state: %d\n",
 283                         (preempt_and_abort_list) ? "Preempt" : "", tmr_p,
 284                         tmr_p->function, tmr_p->response, cmd->t_state);
 285
 286                 cancel_work_sync(&cmd->work);
 287                 transport_wait_for_tasks(cmd);
 288
 289                 transport_cmd_finish_abort(cmd, 1);
 290                 target_put_sess_cmd(cmd);
 291         }
 292 }
 293
 294 static void core_tmr_drain_state_list(
 295         struct se_device *dev,
 296         struct se_cmd *prout_cmd,
 297         struct se_session *tmr_sess,
 298         int tas,
 299         struct list_head *preempt_and_abort_list)
 300 {
 301         LIST_HEAD(drain_task_list);
 302         struct se_session *sess;
 303         struct se_cmd *cmd, *next;
 304         unsigned long flags;
 305         int rc;
 306
 307         /*
 308          * Complete outstanding commands with TASK_ABORTED SAM status.
 309          *
 310          * This is following sam4r17, section 5.6 Aborting commands, Table 38
 311          * for TMR LUN_RESET:
 312          *
 313          * a) "Yes" indicates that each command that is aborted on an I_T nexus
 314          * other than the one that caused the SCSI device condition is
 315          * completed with TASK ABORTED status, if the TAS bit is set to one in
 316          * the Control mode page (see SPC-4). "No" indicates that no status is
 317          * returned for aborted commands.
 318          *
 319          * d) If the logical unit reset is caused by a particular I_T nexus
 320          * (e.g., by a LOGICAL UNIT RESET task management function), then "yes"
 321          * (TASK_ABORTED status) applies.
 322          *
 323          * Otherwise (e.g., if triggered by a hard reset), "no"
 324          * (no TASK_ABORTED SAM status) applies.
 325          *
 326          * Note that this seems to be independent of TAS (Task Aborted Status)
 327          * in the Control Mode Page.
 328          */
 329         spin_lock_irqsave(&dev->execute_task_lock, flags);
 330         list_for_each_entry_safe(cmd, next, &dev->state_list, state_list) {
 331                 /*
 332                  * For PREEMPT_AND_ABORT usage, only process commands
 333                  * with a matching reservation key.
 334                  */
 335                 if (target_check_cdb_and_preempt(preempt_and_abort_list, cmd))
 336                         continue;
 337
 338                 /*
 339                  * Not aborting PROUT PREEMPT_AND_ABORT CDB..
 340                  */
 341                 if (prout_cmd == cmd)
 342                         continue;
 343
 344                 sess = cmd->se_sess;
 345                 if (WARN_ON_ONCE(!sess))
 346                         continue;
 347
 348                 spin_lock(&sess->sess_cmd_lock);
 349                 rc = __target_check_io_state(cmd, tmr_sess, tas);
 350                 spin_unlock(&sess->sess_cmd_lock);
 351                 if (!rc)
 352                         continue;
 353
 354                 list_move_tail(&cmd->state_list, &drain_task_list);
 355                 cmd->state_active = false;
 356         }
 357         spin_unlock_irqrestore(&dev->execute_task_lock, flags);
 358
 359         while (!list_empty(&drain_task_list)) {
 360                 cmd = list_entry(drain_task_list.next, struct se_cmd, state_list);
 361                 list_del_init(&cmd->state_list);
 362
 363                 pr_debug("LUN_RESET: %s cmd: %p"
 364                         " ITT/CmdSN: 0x%08llx/0x%08x, i_state: %d, t_state: %d"
 365                         "cdb: 0x%02x\n",
 366                         (preempt_and_abort_list) ? "Preempt" : "", cmd,
 367                         cmd->tag, 0,
 368                         cmd->se_tfo->get_cmd_state(cmd), cmd->t_state,
 369                         cmd->t_task_cdb[0]);
 370                 pr_debug("LUN_RESET: ITT[0x%08llx] - pr_res_key: 0x%016Lx"
 371                         " -- CMD_T_ACTIVE: %d"
 372                         " CMD_T_STOP: %d CMD_T_SENT: %d\n",
 373                         cmd->tag, cmd->pr_res_key,
 374                         (cmd->transport_state & CMD_T_ACTIVE) != 0,
 375                         (cmd->transport_state & CMD_T_STOP) != 0,
 376                         (cmd->transport_state & CMD_T_SENT) != 0);
 377
 378                 /*
 379                  * If the command may be queued onto a workqueue cancel it now.
 380                  *
 381                  * This is equivalent to removal from the execute queue in the
 382                  * loop above, but we do it down here given that
 383                  * cancel_work_sync may block.
 384                  */
 385                 cancel_work_sync(&cmd->work);
 386                 transport_wait_for_tasks(cmd);
 387
 388                 core_tmr_handle_tas_abort(cmd, tas);
 389                 target_put_sess_cmd(cmd);
 390         }
 391 }
 392
 393 int core_tmr_lun_reset(
 394         struct se_device *dev,
 395         struct se_tmr_req *tmr,
 396         struct list_head *preempt_and_abort_list,
 397         struct se_cmd *prout_cmd)
 398 {
 399         struct se_node_acl *tmr_nacl = NULL;
 400         struct se_portal_group *tmr_tpg = NULL;
 401         struct se_session *tmr_sess = NULL;
 402         int tas;
 403         /*
 404          * TASK_ABORTED status bit, this is configurable via ConfigFS
 405          * struct se_device attributes.  spc4r17 section 7.4.6 Control mode page
 406          *
 407          * A task aborted status (TAS) bit set to zero specifies that aborted
 408          * tasks shall be terminated by the device server without any response
 409          * to the application client. A TAS bit set to one specifies that tasks
 410          * aborted by the actions of an I_T nexus other than the I_T nexus on
 411          * which the command was received shall be completed with TASK ABORTED
 412          * status (see SAM-4).
 413          */
 414         tas = dev->dev_attrib.emulate_tas;
 415         /*
 416          * Determine if this se_tmr is coming from a $FABRIC_MOD
 417          * or struct se_device passthrough..
 418          */
 419         if (tmr && tmr->task_cmd && tmr->task_cmd->se_sess) {
 420                 tmr_sess = tmr->task_cmd->se_sess;
 421                 tmr_nacl = tmr_sess->se_node_acl;
 422                 tmr_tpg = tmr_sess->se_tpg;
 423                 if (tmr_nacl && tmr_tpg) {
 424                         pr_debug("LUN_RESET: TMR caller fabric: %s"
 425                                 " initiator port %s\n",
 426                                 tmr_tpg->se_tpg_tfo->get_fabric_name(),
 427                                 tmr_nacl->initiatorname);
 428                 }
 429         }
 430         pr_debug("LUN_RESET: %s starting for [%s], tas: %d\n",
 431                 (preempt_and_abort_list) ? "Preempt" : "TMR",
 432                 dev->transport->name, tas);
 433
 434         core_tmr_drain_tmr_list(dev, tmr, preempt_and_abort_list);
 435         core_tmr_drain_state_list(dev, prout_cmd, tmr_sess, tas,
 436                                 preempt_and_abort_list);
 437
 438         /*
 439          * Clear any legacy SPC-2 reservation when called during
 440          * LOGICAL UNIT RESET
 441          */
 442         if (!preempt_and_abort_list &&
 443              (dev->dev_reservation_flags & DRF_SPC2_RESERVATIONS)) {
 444                 spin_lock(&dev->dev_reservation_lock);
 445                 dev->dev_reserved_node_acl = NULL;
 446                 dev->dev_reservation_flags &= ~DRF_SPC2_RESERVATIONS;
 447                 spin_unlock(&dev->dev_reservation_lock);
 448                 pr_debug("LUN_RESET: SCSI-2 Released reservation\n");
 449         }
 450
 451         atomic_long_inc(&dev->num_resets);
 452
 453         pr_debug("LUN_RESET: %s for [%s] Complete\n",
 454                         (preempt_and_abort_list) ? "Preempt" : "TMR",
 455                         dev->transport->name);
 456         return 0;
 457 }
 458