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