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