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->fabric_name, ref_tag);
 167
 168                 if (!__target_check_io_state(se_cmd, se_sess,
 169                                              dev->dev_attrib.emulate_tas))
 170                         continue;
 171
 172                 spin_unlock_irqrestore(&se_sess->sess_cmd_lock, flags);
 173
 174                 /*
 175                  * Ensure that this ABORT request is visible to the LU RESET
 176                  * code.
 177                  */
 178                 if (!tmr->tmr_dev)
 179                         WARN_ON_ONCE(transport_lookup_tmr_lun(tmr->task_cmd,
 180                                                 se_cmd->orig_fe_lun) < 0);
 181
 182                 target_put_cmd_and_wait(se_cmd);
 183
 184                 printk("ABORT_TASK: Sending TMR_FUNCTION_COMPLETE for"
 185                                 " ref_tag: %llu\n", ref_tag);
 186                 tmr->response = TMR_FUNCTION_COMPLETE;
 187                 atomic_long_inc(&dev->aborts_complete);
 188                 return;
 189         }
 190         spin_unlock_irqrestore(&se_sess->sess_cmd_lock, flags);
 191
 192         printk("ABORT_TASK: Sending TMR_TASK_DOES_NOT_EXIST for ref_tag: %lld\n",
 193                         tmr->ref_task_tag);
 194         tmr->response = TMR_TASK_DOES_NOT_EXIST;
 195         atomic_long_inc(&dev->aborts_no_task);
 196 }
 197
 198 static void core_tmr_drain_tmr_list(
 199         struct se_device *dev,
 200         struct se_tmr_req *tmr,
 201         struct list_head *preempt_and_abort_list)
 202 {
 203         LIST_HEAD(drain_tmr_list);
 204         struct se_session *sess;
 205         struct se_tmr_req *tmr_p, *tmr_pp;
 206         struct se_cmd *cmd;
 207         unsigned long flags;
 208         bool rc;
 209         /*
 210          * Release all pending and outgoing TMRs aside from the received
 211          * LUN_RESET tmr..
 212          */
 213         spin_lock_irqsave(&dev->se_tmr_lock, flags);
 214         if (tmr)
 215                 list_del_init(&tmr->tmr_list);
 216         list_for_each_entry_safe(tmr_p, tmr_pp, &dev->dev_tmr_list, tmr_list) {
 217                 cmd = tmr_p->task_cmd;
 218                 if (!cmd) {
 219                         pr_err("Unable to locate struct se_cmd for TMR\n");
 220                         continue;
 221                 }
 222                 /*
 223                  * If this function was called with a valid pr_res_key
 224                  * parameter (eg: for PROUT PREEMPT_AND_ABORT service action
 225                  * skip non registration key matching TMRs.
 226                  */
 227                 if (target_check_cdb_and_preempt(preempt_and_abort_list, cmd))
 228                         continue;
 229
 230                 sess = cmd->se_sess;
 231                 if (WARN_ON_ONCE(!sess))
 232                         continue;
 233
 234                 spin_lock(&sess->sess_cmd_lock);
 235                 spin_lock(&cmd->t_state_lock);
 236                 if (!(cmd->transport_state & CMD_T_ACTIVE) ||
 237                      (cmd->transport_state & CMD_T_FABRIC_STOP)) {
 238                         spin_unlock(&cmd->t_state_lock);
 239                         spin_unlock(&sess->sess_cmd_lock);
 240                         continue;
 241                 }
 242                 if (cmd->t_state == TRANSPORT_ISTATE_PROCESSING) {
 243                         spin_unlock(&cmd->t_state_lock);
 244                         spin_unlock(&sess->sess_cmd_lock);
 245                         continue;
 246                 }
 247                 if (sess->sess_tearing_down) {
 248                         spin_unlock(&cmd->t_state_lock);
 249                         spin_unlock(&sess->sess_cmd_lock);
 250                         continue;
 251                 }
 252                 cmd->transport_state |= CMD_T_ABORTED;
 253                 spin_unlock(&cmd->t_state_lock);
 254
 255                 rc = kref_get_unless_zero(&cmd->cmd_kref);
 256                 if (!rc) {
 257                         printk("LUN_RESET TMR: non-zero kref_get_unless_zero\n");
 258                         spin_unlock(&sess->sess_cmd_lock);
 259                         continue;
 260                 }
 261                 spin_unlock(&sess->sess_cmd_lock);
 262
 263                 list_move_tail(&tmr_p->tmr_list, &drain_tmr_list);
 264         }
 265         spin_unlock_irqrestore(&dev->se_tmr_lock, flags);
 266
 267         list_for_each_entry_safe(tmr_p, tmr_pp, &drain_tmr_list, tmr_list) {
 268                 list_del_init(&tmr_p->tmr_list);
 269                 cmd = tmr_p->task_cmd;
 270
 271                 pr_debug("LUN_RESET: %s releasing TMR %p Function: 0x%02x,"
 272                         " Response: 0x%02x, t_state: %d\n",
 273                         (preempt_and_abort_list) ? "Preempt" : "", tmr_p,
 274                         tmr_p->function, tmr_p->response, cmd->t_state);
 275
 276                 target_put_cmd_and_wait(cmd);
 277         }
 278 }
 279
 280 /**
 281  * core_tmr_drain_state_list() - abort SCSI commands associated with a device
 282  *
 283  * @dev:       Device for which to abort outstanding SCSI commands.
 284  * @prout_cmd: Pointer to the SCSI PREEMPT AND ABORT if this function is called
 285  *             to realize the PREEMPT AND ABORT functionality.
 286  * @tmr_sess:  Session through which the LUN RESET has been received.
 287  * @tas:       Task Aborted Status (TAS) bit from the SCSI control mode page.
 288  *             A quote from SPC-4, paragraph "7.5.10 Control mode page":
 289  *             "A task aborted status (TAS) bit set to zero specifies that
 290  *             aborted commands shall be terminated by the device server
 291  *             without any response to the application client. A TAS bit set
 292  *             to one specifies that commands aborted by the actions of an I_T
 293  *             nexus other than the I_T nexus on which the command was
 294  *             received shall be completed with TASK ABORTED status."
 295  * @preempt_and_abort_list: For the PREEMPT AND ABORT functionality, a list
 296  *             with registrations that will be preempted.
 297  */
 298 static void core_tmr_drain_state_list(
 299         struct se_device *dev,
 300         struct se_cmd *prout_cmd,
 301         struct se_session *tmr_sess,
 302         int tas,
 303         struct list_head *preempt_and_abort_list)
 304 {
 305         LIST_HEAD(drain_task_list);
 306         struct se_session *sess;
 307         struct se_cmd *cmd, *next;
 308         unsigned long flags;
 309         int rc;
 310
 311         /*
 312          * Complete outstanding commands with TASK_ABORTED SAM status.
 313          *
 314          * This is following sam4r17, section 5.6 Aborting commands, Table 38
 315          * for TMR LUN_RESET:
 316          *
 317          * a) "Yes" indicates that each command that is aborted on an I_T nexus
 318          * other than the one that caused the SCSI device condition is
 319          * completed with TASK ABORTED status, if the TAS bit is set to one in
 320          * the Control mode page (see SPC-4). "No" indicates that no status is
 321          * returned for aborted commands.
 322          *
 323          * d) If the logical unit reset is caused by a particular I_T nexus
 324          * (e.g., by a LOGICAL UNIT RESET task management function), then "yes"
 325          * (TASK_ABORTED status) applies.
 326          *
 327          * Otherwise (e.g., if triggered by a hard reset), "no"
 328          * (no TASK_ABORTED SAM status) applies.
 329          *
 330          * Note that this seems to be independent of TAS (Task Aborted Status)
 331          * in the Control Mode Page.
 332          */
 333         spin_lock_irqsave(&dev->execute_task_lock, flags);
 334         list_for_each_entry_safe(cmd, next, &dev->state_list, state_list) {
 335                 /*
 336                  * For PREEMPT_AND_ABORT usage, only process commands
 337                  * with a matching reservation key.
 338                  */
 339                 if (target_check_cdb_and_preempt(preempt_and_abort_list, cmd))
 340                         continue;
 341
 342                 /*
 343                  * Not aborting PROUT PREEMPT_AND_ABORT CDB..
 344                  */
 345                 if (prout_cmd == cmd)
 346                         continue;
 347
 348                 sess = cmd->se_sess;
 349                 if (WARN_ON_ONCE(!sess))
 350                         continue;
 351
 352                 spin_lock(&sess->sess_cmd_lock);
 353                 rc = __target_check_io_state(cmd, tmr_sess, tas);
 354                 spin_unlock(&sess->sess_cmd_lock);
 355                 if (!rc)
 356                         continue;
 357
 358                 list_move_tail(&cmd->state_list, &drain_task_list);
 359                 cmd->state_active = false;
 360         }
 361         spin_unlock_irqrestore(&dev->execute_task_lock, flags);
 362
 363         while (!list_empty(&drain_task_list)) {
 364                 cmd = list_entry(drain_task_list.next, struct se_cmd, state_list);
 365                 list_del_init(&cmd->state_list);
 366
 367                 target_show_cmd("LUN_RESET: ", cmd);
 368                 pr_debug("LUN_RESET: ITT[0x%08llx] - %s pr_res_key: 0x%016Lx\n",
 369                          cmd->tag, (preempt_and_abort_list) ? "preempt" : "",
 370                          cmd->pr_res_key);
 371
 372                 target_put_cmd_and_wait(cmd);
 373         }
 374 }
 375
 376 int core_tmr_lun_reset(
 377         struct se_device *dev,
 378         struct se_tmr_req *tmr,
 379         struct list_head *preempt_and_abort_list,
 380         struct se_cmd *prout_cmd)
 381 {
 382         struct se_node_acl *tmr_nacl = NULL;
 383         struct se_portal_group *tmr_tpg = NULL;
 384         struct se_session *tmr_sess = NULL;
 385         int tas;
 386         /*
 387          * TASK_ABORTED status bit, this is configurable via ConfigFS
 388          * struct se_device attributes.  spc4r17 section 7.4.6 Control mode page
 389          *
 390          * A task aborted status (TAS) bit set to zero specifies that aborted
 391          * tasks shall be terminated by the device server without any response
 392          * to the application client. A TAS bit set to one specifies that tasks
 393          * aborted by the actions of an I_T nexus other than the I_T nexus on
 394          * which the command was received shall be completed with TASK ABORTED
 395          * status (see SAM-4).
 396          */
 397         tas = dev->dev_attrib.emulate_tas;
 398         /*
 399          * Determine if this se_tmr is coming from a $FABRIC_MOD
 400          * or struct se_device passthrough..
 401          */
 402         if (tmr && tmr->task_cmd && tmr->task_cmd->se_sess) {
 403                 tmr_sess = tmr->task_cmd->se_sess;
 404                 tmr_nacl = tmr_sess->se_node_acl;
 405                 tmr_tpg = tmr_sess->se_tpg;
 406                 if (tmr_nacl && tmr_tpg) {
 407                         pr_debug("LUN_RESET: TMR caller fabric: %s"
 408                                 " initiator port %s\n",
 409                                 tmr_tpg->se_tpg_tfo->fabric_name,
 410                                 tmr_nacl->initiatorname);
 411                 }
 412         }
 413         pr_debug("LUN_RESET: %s starting for [%s], tas: %d\n",
 414                 (preempt_and_abort_list) ? "Preempt" : "TMR",
 415                 dev->transport->name, tas);
 416
 417         core_tmr_drain_tmr_list(dev, tmr, preempt_and_abort_list);
 418         core_tmr_drain_state_list(dev, prout_cmd, tmr_sess, tas,
 419                                 preempt_and_abort_list);
 420
 421         /*
 422          * Clear any legacy SPC-2 reservation when called during
 423          * LOGICAL UNIT RESET
 424          */
 425         if (!preempt_and_abort_list &&
 426              (dev->dev_reservation_flags & DRF_SPC2_RESERVATIONS)) {
 427                 spin_lock(&dev->dev_reservation_lock);
 428                 dev->dev_reserved_node_acl = NULL;
 429                 dev->dev_reservation_flags &= ~DRF_SPC2_RESERVATIONS;
 430                 spin_unlock(&dev->dev_reservation_lock);
 431                 pr_debug("LUN_RESET: SCSI-2 Released reservation\n");
 432         }
 433
 434         atomic_long_inc(&dev->num_resets);
 435
 436         pr_debug("LUN_RESET: %s for [%s] Complete\n",
 437                         (preempt_and_abort_list) ? "Preempt" : "TMR",
 438                         dev->transport->name);
 439         return 0;
 440 }
 441