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