drivers/target/target_core_tmr.c

   1 // SPDX-License-Identifier: GPL-2.0-or-later
   2 /*******************************************************************************
   3  * Filename:  target_core_tmr.c
   4  *
   5  * This file contains SPC-3 task management infrastructure
   6  *
   7  * (c) Copyright 2009-2013 Datera, Inc.
   8  *
   9  * Nicholas A. Bellinger <nab@kernel.org>
  10  *
  11  ******************************************************************************/
  12
  13 #include <linux/slab.h>
  14 #include <linux/spinlock.h>
  15 #include <linux/list.h>
  16 #include <linux/export.h>
  17
  18 #include <target/target_core_base.h>
  19 #include <target/target_core_backend.h>
  20 #include <target/target_core_fabric.h>
  21
  22 #include "target_core_internal.h"
  23 #include "target_core_alua.h"
  24 #include "target_core_pr.h"
  25
  26 int core_tmr_alloc_req(
  27         struct se_cmd *se_cmd,
  28         void *fabric_tmr_ptr,
  29         u8 function,
  30         gfp_t gfp_flags)
  31 {
  32         struct se_tmr_req *tmr;
  33
  34         tmr = kzalloc(sizeof(struct se_tmr_req), gfp_flags);
  35         if (!tmr) {
  36                 pr_err("Unable to allocate struct se_tmr_req\n");
  37                 return -ENOMEM;
  38         }
  39
  40         se_cmd->se_cmd_flags |= SCF_SCSI_TMR_CDB;
  41         se_cmd->se_tmr_req = tmr;
  42         tmr->task_cmd = se_cmd;
  43         tmr->fabric_tmr_ptr = fabric_tmr_ptr;
  44         tmr->function = function;
  45         INIT_LIST_HEAD(&tmr->tmr_list);
  46
  47         return 0;
  48 }
  49 EXPORT_SYMBOL(core_tmr_alloc_req);
  50
  51 void core_tmr_release_req(struct se_tmr_req *tmr)
  52 {
  53         kfree(tmr);
  54 }
  55
  56 static int target_check_cdb_and_preempt(struct list_head *list,
  57                 struct se_cmd *cmd)
  58 {
  59         struct t10_pr_registration *reg;
  60
  61         if (!list)
  62                 return 0;
  63         list_for_each_entry(reg, list, pr_reg_abort_list) {
  64                 if (reg->pr_res_key == cmd->pr_res_key)
  65                         return 0;
  66         }
  67
  68         return 1;
  69 }
  70
  71 static bool __target_check_io_state(struct se_cmd *se_cmd,
  72                                     struct se_session *tmr_sess, bool tas)
  73 {
  74         struct se_session *sess = se_cmd->se_sess;
  75
  76         lockdep_assert_held(&sess->sess_cmd_lock);
  77
  78         /*
  79          * If command already reached CMD_T_COMPLETE state within
  80          * target_complete_cmd() or CMD_T_FABRIC_STOP due to shutdown,
  81          * this se_cmd has been passed to fabric driver and will
  82          * not be aborted.
  83          *
  84          * Otherwise, obtain a local se_cmd->cmd_kref now for TMR
  85          * ABORT_TASK + LUN_RESET for CMD_T_ABORTED processing as
  86          * long as se_cmd->cmd_kref is still active unless zero.
  87          */
  88         spin_lock(&se_cmd->t_state_lock);
  89         if (se_cmd->transport_state & (CMD_T_COMPLETE | CMD_T_FABRIC_STOP)) {
  90                 pr_debug("Attempted to abort io tag: %llu already complete or"
  91                         " fabric stop, skipping\n", se_cmd->tag);
  92                 spin_unlock(&se_cmd->t_state_lock);
  93                 return false;
  94         }
  95         se_cmd->transport_state |= CMD_T_ABORTED;
  96
  97         if ((tmr_sess != se_cmd->se_sess) && tas)
  98                 se_cmd->transport_state |= CMD_T_TAS;
  99
 100         spin_unlock(&se_cmd->t_state_lock);
 101
 102         return kref_get_unless_zero(&se_cmd->cmd_kref);
 103 }
 104
 105 void core_tmr_abort_task(
 106         struct se_device *dev,
 107         struct se_tmr_req *tmr,
 108         struct se_session *se_sess)
 109 {
 110         LIST_HEAD(aborted_list);
 111         struct se_cmd *se_cmd, *next;
 112         unsigned long flags;
 113         bool rc;
 114         u64 ref_tag;
 115         int i;
 116
 117         for (i = 0; i < dev->queue_cnt; i++) {
 118                 flush_work(&dev->queues[i].sq.work);
 119
 120                 spin_lock_irqsave(&dev->queues[i].lock, flags);
 121                 list_for_each_entry_safe(se_cmd, next, &dev->queues[i].state_list,
 122                                          state_list) {
 123                         if (se_sess != se_cmd->se_sess)
 124                                 continue;
 125
 126                         /*
 127                          * skip task management functions, including
 128                          * tmr->task_cmd
 129                          */
 130                         if (se_cmd->se_cmd_flags & SCF_SCSI_TMR_CDB)
 131                                 continue;
 132
 133                         ref_tag = se_cmd->tag;
 134                         if (tmr->ref_task_tag != ref_tag)
 135                                 continue;
 136
 137                         pr_err("ABORT_TASK: Found referenced %s task_tag: %llu\n",
 138                                se_cmd->se_tfo->fabric_name, ref_tag);
 139
 140                         spin_lock(&se_sess->sess_cmd_lock);
 141                         rc = __target_check_io_state(se_cmd, se_sess, 0);
 142                         spin_unlock(&se_sess->sess_cmd_lock);
 143                         if (!rc)
 144                                 continue;
 145
 146                         list_move_tail(&se_cmd->state_list, &aborted_list);
 147                         se_cmd->state_active = false;
 148                         spin_unlock_irqrestore(&dev->queues[i].lock, flags);
 149
 150                         if (dev->transport->tmr_notify)
 151                                 dev->transport->tmr_notify(dev, TMR_ABORT_TASK,
 152                                                            &aborted_list);
 153
 154                         list_del_init(&se_cmd->state_list);
 155                         target_put_cmd_and_wait(se_cmd);
 156
 157                         pr_err("ABORT_TASK: Sending TMR_FUNCTION_COMPLETE for ref_tag: %llu\n",
 158                                ref_tag);
 159                         tmr->response = TMR_FUNCTION_COMPLETE;
 160                         atomic_long_inc(&dev->aborts_complete);
 161                         return;
 162                 }
 163                 spin_unlock_irqrestore(&dev->queues[i].lock, flags);
 164         }
 165
 166         if (dev->transport->tmr_notify)
 167                 dev->transport->tmr_notify(dev, TMR_ABORT_TASK, &aborted_list);
 168
 169         printk("ABORT_TASK: Sending TMR_TASK_DOES_NOT_EXIST for ref_tag: %lld\n",
 170                         tmr->ref_task_tag);
 171         tmr->response = TMR_TASK_DOES_NOT_EXIST;
 172         atomic_long_inc(&dev->aborts_no_task);
 173 }
 174
 175 static void core_tmr_drain_tmr_list(
 176         struct se_device *dev,
 177         struct se_tmr_req *tmr,
 178         struct list_head *preempt_and_abort_list)
 179 {
 180         LIST_HEAD(drain_tmr_list);
 181         struct se_session *sess;
 182         struct se_tmr_req *tmr_p, *tmr_pp;
 183         struct se_cmd *cmd;
 184         unsigned long flags;
 185         bool rc;
 186         /*
 187          * Release all pending and outgoing TMRs aside from the received
 188          * LUN_RESET tmr..
 189          */
 190         spin_lock_irqsave(&dev->se_tmr_lock, flags);
 191         list_for_each_entry_safe(tmr_p, tmr_pp, &dev->dev_tmr_list, tmr_list) {
 192                 if (tmr_p == tmr)
 193                         continue;
 194
 195                 cmd = tmr_p->task_cmd;
 196                 if (!cmd) {
 197                         pr_err("Unable to locate struct se_cmd for TMR\n");
 198                         continue;
 199                 }
 200
 201                 /*
 202                  * We only execute one LUN_RESET at a time so we can't wait
 203                  * on them below.
 204                  */
 205                 if (tmr_p->function == TMR_LUN_RESET)
 206                         continue;
 207
 208                 /*
 209                  * If this function was called with a valid pr_res_key
 210                  * parameter (eg: for PROUT PREEMPT_AND_ABORT service action
 211                  * skip non registration key matching TMRs.
 212                  */
 213                 if (target_check_cdb_and_preempt(preempt_and_abort_list, cmd))
 214                         continue;
 215
 216                 sess = cmd->se_sess;
 217                 if (WARN_ON_ONCE(!sess))
 218                         continue;
 219
 220                 spin_lock(&sess->sess_cmd_lock);
 221                 rc = __target_check_io_state(cmd, sess, 0);
 222                 spin_unlock(&sess->sess_cmd_lock);
 223
 224                 if (!rc) {
 225                         printk("LUN_RESET TMR: non-zero kref_get_unless_zero\n");
 226                         continue;
 227                 }
 228
 229                 list_move_tail(&tmr_p->tmr_list, &drain_tmr_list);
 230                 tmr_p->tmr_dev = NULL;
 231         }
 232         spin_unlock_irqrestore(&dev->se_tmr_lock, flags);
 233
 234         list_for_each_entry_safe(tmr_p, tmr_pp, &drain_tmr_list, tmr_list) {
 235                 list_del_init(&tmr_p->tmr_list);
 236                 cmd = tmr_p->task_cmd;
 237
 238                 pr_debug("LUN_RESET: %s releasing TMR %p Function: 0x%02x,"
 239                         " Response: 0x%02x, t_state: %d\n",
 240                         (preempt_and_abort_list) ? "Preempt" : "", tmr_p,
 241                         tmr_p->function, tmr_p->response, cmd->t_state);
 242
 243                 target_put_cmd_and_wait(cmd);
 244         }
 245 }
 246
 247 /**
 248  * core_tmr_drain_state_list() - abort SCSI commands associated with a device
 249  *
 250  * @dev:       Device for which to abort outstanding SCSI commands.
 251  * @prout_cmd: Pointer to the SCSI PREEMPT AND ABORT if this function is called
 252  *             to realize the PREEMPT AND ABORT functionality.
 253  * @tmr_sess:  Session through which the LUN RESET has been received.
 254  * @tas:       Task Aborted Status (TAS) bit from the SCSI control mode page.
 255  *             A quote from SPC-4, paragraph "7.5.10 Control mode page":
 256  *             "A task aborted status (TAS) bit set to zero specifies that
 257  *             aborted commands shall be terminated by the device server
 258  *             without any response to the application client. A TAS bit set
 259  *             to one specifies that commands aborted by the actions of an I_T
 260  *             nexus other than the I_T nexus on which the command was
 261  *             received shall be completed with TASK ABORTED status."
 262  * @preempt_and_abort_list: For the PREEMPT AND ABORT functionality, a list
 263  *             with registrations that will be preempted.
 264  */
 265 static void core_tmr_drain_state_list(
 266         struct se_device *dev,
 267         struct se_cmd *prout_cmd,
 268         struct se_session *tmr_sess,
 269         bool tas,
 270         struct list_head *preempt_and_abort_list)
 271 {
 272         LIST_HEAD(drain_task_list);
 273         struct se_session *sess;
 274         struct se_cmd *cmd, *next;
 275         unsigned long flags;
 276         int rc, i;
 277
 278         /*
 279          * Complete outstanding commands with TASK_ABORTED SAM status.
 280          *
 281          * This is following sam4r17, section 5.6 Aborting commands, Table 38
 282          * for TMR LUN_RESET:
 283          *
 284          * a) "Yes" indicates that each command that is aborted on an I_T nexus
 285          * other than the one that caused the SCSI device condition is
 286          * completed with TASK ABORTED status, if the TAS bit is set to one in
 287          * the Control mode page (see SPC-4). "No" indicates that no status is
 288          * returned for aborted commands.
 289          *
 290          * d) If the logical unit reset is caused by a particular I_T nexus
 291          * (e.g., by a LOGICAL UNIT RESET task management function), then "yes"
 292          * (TASK_ABORTED status) applies.
 293          *
 294          * Otherwise (e.g., if triggered by a hard reset), "no"
 295          * (no TASK_ABORTED SAM status) applies.
 296          *
 297          * Note that this seems to be independent of TAS (Task Aborted Status)
 298          * in the Control Mode Page.
 299          */
 300         for (i = 0; i < dev->queue_cnt; i++) {
 301                 flush_work(&dev->queues[i].sq.work);
 302
 303                 spin_lock_irqsave(&dev->queues[i].lock, flags);
 304                 list_for_each_entry_safe(cmd, next, &dev->queues[i].state_list,
 305                                          state_list) {
 306                         /*
 307                          * For PREEMPT_AND_ABORT usage, only process commands
 308                          * with a matching reservation key.
 309                          */
 310                         if (target_check_cdb_and_preempt(preempt_and_abort_list,
 311                                                          cmd))
 312                                 continue;
 313
 314                         /*
 315                          * Not aborting PROUT PREEMPT_AND_ABORT CDB..
 316                          */
 317                         if (prout_cmd == cmd)
 318                                 continue;
 319
 320                         sess = cmd->se_sess;
 321                         if (WARN_ON_ONCE(!sess))
 322                                 continue;
 323
 324                         spin_lock(&sess->sess_cmd_lock);
 325                         rc = __target_check_io_state(cmd, tmr_sess, tas);
 326                         spin_unlock(&sess->sess_cmd_lock);
 327                         if (!rc)
 328                                 continue;
 329
 330                         list_move_tail(&cmd->state_list, &drain_task_list);
 331                         cmd->state_active = false;
 332                 }
 333                 spin_unlock_irqrestore(&dev->queues[i].lock, flags);
 334         }
 335
 336         if (dev->transport->tmr_notify)
 337                 dev->transport->tmr_notify(dev, preempt_and_abort_list ?
 338                                            TMR_LUN_RESET_PRO : TMR_LUN_RESET,
 339                                            &drain_task_list);
 340
 341         while (!list_empty(&drain_task_list)) {
 342                 cmd = list_entry(drain_task_list.next, struct se_cmd, state_list);
 343                 list_del_init(&cmd->state_list);
 344
 345                 target_show_cmd("LUN_RESET: ", cmd);
 346                 pr_debug("LUN_RESET: ITT[0x%08llx] - %s pr_res_key: 0x%016Lx\n",
 347                          cmd->tag, (preempt_and_abort_list) ? "preempt" : "",
 348                          cmd->pr_res_key);
 349
 350                 target_put_cmd_and_wait(cmd);
 351         }
 352 }
 353
 354 int core_tmr_lun_reset(
 355         struct se_device *dev,
 356         struct se_tmr_req *tmr,
 357         struct list_head *preempt_and_abort_list,
 358         struct se_cmd *prout_cmd)
 359 {
 360         struct se_node_acl *tmr_nacl = NULL;
 361         struct se_portal_group *tmr_tpg = NULL;
 362         struct se_session *tmr_sess = NULL;
 363         bool tas;
 364         /*
 365          * TASK_ABORTED status bit, this is configurable via ConfigFS
 366          * struct se_device attributes.  spc4r17 section 7.4.6 Control mode page
 367          *
 368          * A task aborted status (TAS) bit set to zero specifies that aborted
 369          * tasks shall be terminated by the device server without any response
 370          * to the application client. A TAS bit set to one specifies that tasks
 371          * aborted by the actions of an I_T nexus other than the I_T nexus on
 372          * which the command was received shall be completed with TASK ABORTED
 373          * status (see SAM-4).
 374          */
 375         tas = dev->dev_attrib.emulate_tas;
 376         /*
 377          * Determine if this se_tmr is coming from a $FABRIC_MOD
 378          * or struct se_device passthrough..
 379          */
 380         if (tmr && tmr->task_cmd && tmr->task_cmd->se_sess) {
 381                 tmr_sess = tmr->task_cmd->se_sess;
 382                 tmr_nacl = tmr_sess->se_node_acl;
 383                 tmr_tpg = tmr_sess->se_tpg;
 384                 if (tmr_nacl && tmr_tpg) {
 385                         pr_debug("LUN_RESET: TMR caller fabric: %s"
 386                                 " initiator port %s\n",
 387                                 tmr_tpg->se_tpg_tfo->fabric_name,
 388                                 tmr_nacl->initiatorname);
 389                 }
 390         }
 391
 392
 393         /*
 394          * We only allow one reset or preempt and abort to execute at a time
 395          * to prevent one call from claiming all the cmds causing a second
 396          * call from returning while cmds it should have waited on are still
 397          * running.
 398          */
 399         mutex_lock(&dev->lun_reset_mutex);
 400
 401         pr_debug("LUN_RESET: %s starting for [%s], tas: %d\n",
 402                 (preempt_and_abort_list) ? "Preempt" : "TMR",
 403                 dev->transport->name, tas);
 404         core_tmr_drain_tmr_list(dev, tmr, preempt_and_abort_list);
 405         core_tmr_drain_state_list(dev, prout_cmd, tmr_sess, tas,
 406                                 preempt_and_abort_list);
 407
 408         mutex_unlock(&dev->lun_reset_mutex);
 409
 410         /*
 411          * Clear any legacy SPC-2 reservation when called during
 412          * LOGICAL UNIT RESET
 413          */
 414         if (!preempt_and_abort_list &&
 415              (dev->dev_reservation_flags & DRF_SPC2_RESERVATIONS)) {
 416                 spin_lock(&dev->dev_reservation_lock);
 417                 dev->reservation_holder = NULL;
 418                 dev->dev_reservation_flags &= ~DRF_SPC2_RESERVATIONS;
 419                 spin_unlock(&dev->dev_reservation_lock);
 420                 pr_debug("LUN_RESET: SCSI-2 Released reservation\n");
 421         }
 422
 423         atomic_long_inc(&dev->num_resets);
 424
 425         pr_debug("LUN_RESET: %s for [%s] Complete\n",
 426                         (preempt_and_abort_list) ? "Preempt" : "TMR",
 427                         dev->transport->name);
 428         return 0;
 429 }
 430