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                         target_put_sess_cmd(se_cmd);
 181                         goto out;
 182                 }
 183                 list_del_init(&se_cmd->se_cmd_list);
 184                 spin_unlock_irqrestore(&se_sess->sess_cmd_lock, flags);
 185
 186                 cancel_work_sync(&se_cmd->work);
 187                 transport_wait_for_tasks(se_cmd);
 188
 189                 transport_cmd_finish_abort(se_cmd, true);
 190                 target_put_sess_cmd(se_cmd);
 191
 192                 printk("ABORT_TASK: Sending TMR_FUNCTION_COMPLETE for"
 193                                 " ref_tag: %llu\n", ref_tag);
 194                 tmr->response = TMR_FUNCTION_COMPLETE;
 195                 return;
 196         }
 197         spin_unlock_irqrestore(&se_sess->sess_cmd_lock, flags);
 198
 199 out:
 200         printk("ABORT_TASK: Sending TMR_TASK_DOES_NOT_EXIST for ref_tag: %lld\n",
 201                         tmr->ref_task_tag);
 202         tmr->response = TMR_TASK_DOES_NOT_EXIST;
 203 }
 204
 205 static void core_tmr_drain_tmr_list(
 206         struct se_device *dev,
 207         struct se_tmr_req *tmr,
 208         struct list_head *preempt_and_abort_list)
 209 {
 210         LIST_HEAD(drain_tmr_list);
 211         struct se_session *sess;
 212         struct se_tmr_req *tmr_p, *tmr_pp;
 213         struct se_cmd *cmd;
 214         unsigned long flags;
 215         bool rc;
 216         /*
 217          * Release all pending and outgoing TMRs aside from the received
 218          * LUN_RESET tmr..
 219          */
 220         spin_lock_irqsave(&dev->se_tmr_lock, flags);
 221         list_for_each_entry_safe(tmr_p, tmr_pp, &dev->dev_tmr_list, tmr_list) {
 222                 /*
 223                  * Allow the received TMR to return with FUNCTION_COMPLETE.
 224                  */
 225                 if (tmr_p == tmr)
 226                         continue;
 227
 228                 cmd = tmr_p->task_cmd;
 229                 if (!cmd) {
 230                         pr_err("Unable to locate struct se_cmd for TMR\n");
 231                         continue;
 232                 }
 233                 /*
 234                  * If this function was called with a valid pr_res_key
 235                  * parameter (eg: for PROUT PREEMPT_AND_ABORT service action
 236                  * skip non registration key matching TMRs.
 237                  */
 238                 if (target_check_cdb_and_preempt(preempt_and_abort_list, cmd))
 239                         continue;
 240
 241                 sess = cmd->se_sess;
 242                 if (WARN_ON_ONCE(!sess))
 243                         continue;
 244
 245                 spin_lock(&sess->sess_cmd_lock);
 246                 spin_lock(&cmd->t_state_lock);
 247                 if (!(cmd->transport_state & CMD_T_ACTIVE) ||
 248                      (cmd->transport_state & CMD_T_FABRIC_STOP)) {
 249                         spin_unlock(&cmd->t_state_lock);
 250                         spin_unlock(&sess->sess_cmd_lock);
 251                         continue;
 252                 }
 253                 if (cmd->t_state == TRANSPORT_ISTATE_PROCESSING) {
 254                         spin_unlock(&cmd->t_state_lock);
 255                         spin_unlock(&sess->sess_cmd_lock);
 256                         continue;
 257                 }
 258                 if (sess->sess_tearing_down || cmd->cmd_wait_set) {
 259                         spin_unlock(&cmd->t_state_lock);
 260                         spin_unlock(&sess->sess_cmd_lock);
 261                         continue;
 262                 }
 263                 cmd->transport_state |= CMD_T_ABORTED;
 264                 spin_unlock(&cmd->t_state_lock);
 265
 266                 rc = kref_get_unless_zero(&cmd->cmd_kref);
 267                 if (!rc) {
 268                         printk("LUN_RESET TMR: non-zero kref_get_unless_zero\n");
 269                         spin_unlock(&sess->sess_cmd_lock);
 270                         continue;
 271                 }
 272                 spin_unlock(&sess->sess_cmd_lock);
 273
 274                 list_move_tail(&tmr_p->tmr_list, &drain_tmr_list);
 275         }
 276         spin_unlock_irqrestore(&dev->se_tmr_lock, flags);
 277
 278         list_for_each_entry_safe(tmr_p, tmr_pp, &drain_tmr_list, tmr_list) {
 279                 list_del_init(&tmr_p->tmr_list);
 280                 cmd = tmr_p->task_cmd;
 281
 282                 pr_debug("LUN_RESET: %s releasing TMR %p Function: 0x%02x,"
 283                         " Response: 0x%02x, t_state: %d\n",
 284                         (preempt_and_abort_list) ? "Preempt" : "", tmr_p,
 285                         tmr_p->function, tmr_p->response, cmd->t_state);
 286
 287                 cancel_work_sync(&cmd->work);
 288                 transport_wait_for_tasks(cmd);
 289
 290                 transport_cmd_finish_abort(cmd, 1);
 291                 target_put_sess_cmd(cmd);
 292         }
 293 }
 294
 295 static void core_tmr_drain_state_list(
 296         struct se_device *dev,
 297         struct se_cmd *prout_cmd,
 298         struct se_session *tmr_sess,
 299         int tas,
 300         struct list_head *preempt_and_abort_list)
 301 {
 302         LIST_HEAD(drain_task_list);
 303         struct se_session *sess;
 304         struct se_cmd *cmd, *next;
 305         unsigned long flags;
 306         int rc;
 307
 308         /*
 309          * Complete outstanding commands with TASK_ABORTED SAM status.
 310          *
 311          * This is following sam4r17, section 5.6 Aborting commands, Table 38
 312          * for TMR LUN_RESET:
 313          *
 314          * a) "Yes" indicates that each command that is aborted on an I_T nexus
 315          * other than the one that caused the SCSI device condition is
 316          * completed with TASK ABORTED status, if the TAS bit is set to one in
 317          * the Control mode page (see SPC-4). "No" indicates that no status is
 318          * returned for aborted commands.
 319          *
 320          * d) If the logical unit reset is caused by a particular I_T nexus
 321          * (e.g., by a LOGICAL UNIT RESET task management function), then "yes"
 322          * (TASK_ABORTED status) applies.
 323          *
 324          * Otherwise (e.g., if triggered by a hard reset), "no"
 325          * (no TASK_ABORTED SAM status) applies.
 326          *
 327          * Note that this seems to be independent of TAS (Task Aborted Status)
 328          * in the Control Mode Page.
 329          */
 330         spin_lock_irqsave(&dev->execute_task_lock, flags);
 331         list_for_each_entry_safe(cmd, next, &dev->state_list, state_list) {
 332                 /*
 333                  * For PREEMPT_AND_ABORT usage, only process commands
 334                  * with a matching reservation key.
 335                  */
 336                 if (target_check_cdb_and_preempt(preempt_and_abort_list, cmd))
 337                         continue;
 338
 339                 /*
 340                  * Not aborting PROUT PREEMPT_AND_ABORT CDB..
 341                  */
 342                 if (prout_cmd == cmd)
 343                         continue;
 344
 345                 sess = cmd->se_sess;
 346                 if (WARN_ON_ONCE(!sess))
 347                         continue;
 348
 349                 spin_lock(&sess->sess_cmd_lock);
 350                 rc = __target_check_io_state(cmd, tmr_sess, tas);
 351                 spin_unlock(&sess->sess_cmd_lock);
 352                 if (!rc)
 353                         continue;
 354
 355                 list_move_tail(&cmd->state_list, &drain_task_list);
 356                 cmd->state_active = false;
 357         }
 358         spin_unlock_irqrestore(&dev->execute_task_lock, flags);
 359
 360         while (!list_empty(&drain_task_list)) {
 361                 cmd = list_entry(drain_task_list.next, struct se_cmd, state_list);
 362                 list_del_init(&cmd->state_list);
 363
 364                 pr_debug("LUN_RESET: %s cmd: %p"
 365                         " ITT/CmdSN: 0x%08llx/0x%08x, i_state: %d, t_state: %d"
 366                         "cdb: 0x%02x\n",
 367                         (preempt_and_abort_list) ? "Preempt" : "", cmd,
 368                         cmd->tag, 0,
 369                         cmd->se_tfo->get_cmd_state(cmd), cmd->t_state,
 370                         cmd->t_task_cdb[0]);
 371                 pr_debug("LUN_RESET: ITT[0x%08llx] - pr_res_key: 0x%016Lx"
 372                         " -- CMD_T_ACTIVE: %d"
 373                         " CMD_T_STOP: %d CMD_T_SENT: %d\n",
 374                         cmd->tag, cmd->pr_res_key,
 375                         (cmd->transport_state & CMD_T_ACTIVE) != 0,
 376                         (cmd->transport_state & CMD_T_STOP) != 0,
 377                         (cmd->transport_state & CMD_T_SENT) != 0);
 378
 379                 /*
 380                  * If the command may be queued onto a workqueue cancel it now.
 381                  *
 382                  * This is equivalent to removal from the execute queue in the
 383                  * loop above, but we do it down here given that
 384                  * cancel_work_sync may block.
 385                  */
 386                 cancel_work_sync(&cmd->work);
 387                 transport_wait_for_tasks(cmd);
 388
 389                 core_tmr_handle_tas_abort(cmd, tas);
 390                 target_put_sess_cmd(cmd);
 391         }
 392 }
 393
 394 int core_tmr_lun_reset(
 395         struct se_device *dev,
 396         struct se_tmr_req *tmr,
 397         struct list_head *preempt_and_abort_list,
 398         struct se_cmd *prout_cmd)
 399 {
 400         struct se_node_acl *tmr_nacl = NULL;
 401         struct se_portal_group *tmr_tpg = NULL;
 402         struct se_session *tmr_sess = NULL;
 403         int tas;
 404         /*
 405          * TASK_ABORTED status bit, this is configurable via ConfigFS
 406          * struct se_device attributes.  spc4r17 section 7.4.6 Control mode page
 407          *
 408          * A task aborted status (TAS) bit set to zero specifies that aborted
 409          * tasks shall be terminated by the device server without any response
 410          * to the application client. A TAS bit set to one specifies that tasks
 411          * aborted by the actions of an I_T nexus other than the I_T nexus on
 412          * which the command was received shall be completed with TASK ABORTED
 413          * status (see SAM-4).
 414          */
 415         tas = dev->dev_attrib.emulate_tas;
 416         /*
 417          * Determine if this se_tmr is coming from a $FABRIC_MOD
 418          * or struct se_device passthrough..
 419          */
 420         if (tmr && tmr->task_cmd && tmr->task_cmd->se_sess) {
 421                 tmr_sess = tmr->task_cmd->se_sess;
 422                 tmr_nacl = tmr_sess->se_node_acl;
 423                 tmr_tpg = tmr_sess->se_tpg;
 424                 if (tmr_nacl && tmr_tpg) {
 425                         pr_debug("LUN_RESET: TMR caller fabric: %s"
 426                                 " initiator port %s\n",
 427                                 tmr_tpg->se_tpg_tfo->get_fabric_name(),
 428                                 tmr_nacl->initiatorname);
 429                 }
 430         }
 431         pr_debug("LUN_RESET: %s starting for [%s], tas: %d\n",
 432                 (preempt_and_abort_list) ? "Preempt" : "TMR",
 433                 dev->transport->name, tas);
 434
 435         core_tmr_drain_tmr_list(dev, tmr, preempt_and_abort_list);
 436         core_tmr_drain_state_list(dev, prout_cmd, tmr_sess, tas,
 437                                 preempt_and_abort_list);
 438
 439         /*
 440          * Clear any legacy SPC-2 reservation when called during
 441          * LOGICAL UNIT RESET
 442          */
 443         if (!preempt_and_abort_list &&
 444              (dev->dev_reservation_flags & DRF_SPC2_RESERVATIONS)) {
 445                 spin_lock(&dev->dev_reservation_lock);
 446                 dev->dev_reserved_node_acl = NULL;
 447                 dev->dev_reservation_flags &= ~DRF_SPC2_RESERVATIONS;
 448                 spin_unlock(&dev->dev_reservation_lock);
 449                 pr_debug("LUN_RESET: SCSI-2 Released reservation\n");
 450         }
 451
 452         atomic_long_inc(&dev->num_resets);
 453
 454         pr_debug("LUN_RESET: %s for [%s] Complete\n",
 455                         (preempt_and_abort_list) ? "Preempt" : "TMR",
 456                         dev->transport->name);
 457         return 0;
 458 }
 459