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