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