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