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         lockdep_assert_held(&sess->sess_cmd_lock);
  86
  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                 spin_lock_irqsave(&dev->queues[i].lock, flags);
 128                 list_for_each_entry_safe(se_cmd, next, &dev->queues[i].state_list,
 129                                          state_list) {
 130                         if (se_sess != se_cmd->se_sess)
 131                                 continue;
 132
 133                         /*
 134                          * skip task management functions, including
 135                          * tmr->task_cmd
 136                          */
 137                         if (se_cmd->se_cmd_flags & SCF_SCSI_TMR_CDB)
 138                                 continue;
 139
 140                         ref_tag = se_cmd->tag;
 141                         if (tmr->ref_task_tag != ref_tag)
 142                                 continue;
 143
 144                         pr_err("ABORT_TASK: Found referenced %s task_tag: %llu\n",
 145                                se_cmd->se_tfo->fabric_name, ref_tag);
 146
 147                         spin_lock(&se_sess->sess_cmd_lock);
 148                         rc = __target_check_io_state(se_cmd, se_sess, 0);
 149                         spin_unlock(&se_sess->sess_cmd_lock);
 150                         if (!rc)
 151                                 continue;
 152
 153                         list_move_tail(&se_cmd->state_list, &aborted_list);
 154                         se_cmd->state_active = false;
 155                         spin_unlock_irqrestore(&dev->queues[i].lock, flags);
 156
 157                         /*
 158                          * Ensure that this ABORT request is visible to the LU
 159                          * RESET code.
 160                          */
 161                         if (!tmr->tmr_dev)
 162                                 WARN_ON_ONCE(transport_lookup_tmr_lun(tmr->task_cmd) < 0);
 163
 164                         if (dev->transport->tmr_notify)
 165                                 dev->transport->tmr_notify(dev, TMR_ABORT_TASK,
 166                                                            &aborted_list);
 167
 168                         list_del_init(&se_cmd->state_list);
 169                         target_put_cmd_and_wait(se_cmd);
 170
 171                         pr_err("ABORT_TASK: Sending TMR_FUNCTION_COMPLETE for ref_tag: %llu\n",
 172                                ref_tag);
 173                         tmr->response = TMR_FUNCTION_COMPLETE;
 174                         atomic_long_inc(&dev->aborts_complete);
 175                         return;
 176                 }
 177                 spin_unlock_irqrestore(&dev->queues[i].lock, flags);
 178         }
 179
 180         if (dev->transport->tmr_notify)
 181                 dev->transport->tmr_notify(dev, TMR_ABORT_TASK, &aborted_list);
 182
 183         printk("ABORT_TASK: Sending TMR_TASK_DOES_NOT_EXIST for ref_tag: %lld\n",
 184                         tmr->ref_task_tag);
 185         tmr->response = TMR_TASK_DOES_NOT_EXIST;
 186         atomic_long_inc(&dev->aborts_no_task);
 187 }
 188
 189 static void core_tmr_drain_tmr_list(
 190         struct se_device *dev,
 191         struct se_tmr_req *tmr,
 192         struct list_head *preempt_and_abort_list)
 193 {
 194         LIST_HEAD(drain_tmr_list);
 195         struct se_session *sess;
 196         struct se_tmr_req *tmr_p, *tmr_pp;
 197         struct se_cmd *cmd;
 198         unsigned long flags;
 199         bool rc;
 200         /*
 201          * Release all pending and outgoing TMRs aside from the received
 202          * LUN_RESET tmr..
 203          */
 204         spin_lock_irqsave(&dev->se_tmr_lock, flags);
 205         list_for_each_entry_safe(tmr_p, tmr_pp, &dev->dev_tmr_list, tmr_list) {
 206                 if (tmr_p == tmr)
 207                         continue;
 208
 209                 cmd = tmr_p->task_cmd;
 210                 if (!cmd) {
 211                         pr_err("Unable to locate struct se_cmd for TMR\n");
 212                         continue;
 213                 }
 214
 215                 /*
 216                  * We only execute one LUN_RESET at a time so we can't wait
 217                  * on them below.
 218                  */
 219                 if (tmr_p->function == TMR_LUN_RESET)
 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                 rc = __target_check_io_state(cmd, sess, 0);
 236                 spin_unlock(&sess->sess_cmd_lock);
 237
 238                 if (!rc) {
 239                         printk("LUN_RESET TMR: non-zero kref_get_unless_zero\n");
 240                         continue;
 241                 }
 242
 243                 list_move_tail(&tmr_p->tmr_list, &drain_tmr_list);
 244         }
 245         spin_unlock_irqrestore(&dev->se_tmr_lock, flags);
 246
 247         list_for_each_entry_safe(tmr_p, tmr_pp, &drain_tmr_list, tmr_list) {
 248                 list_del_init(&tmr_p->tmr_list);
 249                 cmd = tmr_p->task_cmd;
 250
 251                 pr_debug("LUN_RESET: %s releasing TMR %p Function: 0x%02x,"
 252                         " Response: 0x%02x, t_state: %d\n",
 253                         (preempt_and_abort_list) ? "Preempt" : "", tmr_p,
 254                         tmr_p->function, tmr_p->response, cmd->t_state);
 255
 256                 target_put_cmd_and_wait(cmd);
 257         }
 258 }
 259
 260 /**
 261  * core_tmr_drain_state_list() - abort SCSI commands associated with a device
 262  *
 263  * @dev:       Device for which to abort outstanding SCSI commands.
 264  * @prout_cmd: Pointer to the SCSI PREEMPT AND ABORT if this function is called
 265  *             to realize the PREEMPT AND ABORT functionality.
 266  * @tmr_sess:  Session through which the LUN RESET has been received.
 267  * @tas:       Task Aborted Status (TAS) bit from the SCSI control mode page.
 268  *             A quote from SPC-4, paragraph "7.5.10 Control mode page":
 269  *             "A task aborted status (TAS) bit set to zero specifies that
 270  *             aborted commands shall be terminated by the device server
 271  *             without any response to the application client. A TAS bit set
 272  *             to one specifies that commands aborted by the actions of an I_T
 273  *             nexus other than the I_T nexus on which the command was
 274  *             received shall be completed with TASK ABORTED status."
 275  * @preempt_and_abort_list: For the PREEMPT AND ABORT functionality, a list
 276  *             with registrations that will be preempted.
 277  */
 278 static void core_tmr_drain_state_list(
 279         struct se_device *dev,
 280         struct se_cmd *prout_cmd,
 281         struct se_session *tmr_sess,
 282         bool tas,
 283         struct list_head *preempt_and_abort_list)
 284 {
 285         LIST_HEAD(drain_task_list);
 286         struct se_session *sess;
 287         struct se_cmd *cmd, *next;
 288         unsigned long flags;
 289         int rc, i;
 290
 291         /*
 292          * Complete outstanding commands with TASK_ABORTED SAM status.
 293          *
 294          * This is following sam4r17, section 5.6 Aborting commands, Table 38
 295          * for TMR LUN_RESET:
 296          *
 297          * a) "Yes" indicates that each command that is aborted on an I_T nexus
 298          * other than the one that caused the SCSI device condition is
 299          * completed with TASK ABORTED status, if the TAS bit is set to one in
 300          * the Control mode page (see SPC-4). "No" indicates that no status is
 301          * returned for aborted commands.
 302          *
 303          * d) If the logical unit reset is caused by a particular I_T nexus
 304          * (e.g., by a LOGICAL UNIT RESET task management function), then "yes"
 305          * (TASK_ABORTED status) applies.
 306          *
 307          * Otherwise (e.g., if triggered by a hard reset), "no"
 308          * (no TASK_ABORTED SAM status) applies.
 309          *
 310          * Note that this seems to be independent of TAS (Task Aborted Status)
 311          * in the Control Mode Page.
 312          */
 313         for (i = 0; i < dev->queue_cnt; i++) {
 314                 spin_lock_irqsave(&dev->queues[i].lock, flags);
 315                 list_for_each_entry_safe(cmd, next, &dev->queues[i].state_list,
 316                                          state_list) {
 317                         /*
 318                          * For PREEMPT_AND_ABORT usage, only process commands
 319                          * with a matching reservation key.
 320                          */
 321                         if (target_check_cdb_and_preempt(preempt_and_abort_list,
 322                                                          cmd))
 323                                 continue;
 324
 325                         /*
 326                          * Not aborting PROUT PREEMPT_AND_ABORT CDB..
 327                          */
 328                         if (prout_cmd == cmd)
 329                                 continue;
 330
 331                         sess = cmd->se_sess;
 332                         if (WARN_ON_ONCE(!sess))
 333                                 continue;
 334
 335                         spin_lock(&sess->sess_cmd_lock);
 336                         rc = __target_check_io_state(cmd, tmr_sess, tas);
 337                         spin_unlock(&sess->sess_cmd_lock);
 338                         if (!rc)
 339                                 continue;
 340
 341                         list_move_tail(&cmd->state_list, &drain_task_list);
 342                         cmd->state_active = false;
 343                 }
 344                 spin_unlock_irqrestore(&dev->queues[i].lock, flags);
 345         }
 346
 347         if (dev->transport->tmr_notify)
 348                 dev->transport->tmr_notify(dev, preempt_and_abort_list ?
 349                                            TMR_LUN_RESET_PRO : TMR_LUN_RESET,
 350                                            &drain_task_list);
 351
 352         while (!list_empty(&drain_task_list)) {
 353                 cmd = list_entry(drain_task_list.next, struct se_cmd, state_list);
 354                 list_del_init(&cmd->state_list);
 355
 356                 target_show_cmd("LUN_RESET: ", cmd);
 357                 pr_debug("LUN_RESET: ITT[0x%08llx] - %s pr_res_key: 0x%016Lx\n",
 358                          cmd->tag, (preempt_and_abort_list) ? "preempt" : "",
 359                          cmd->pr_res_key);
 360
 361                 target_put_cmd_and_wait(cmd);
 362         }
 363 }
 364
 365 int core_tmr_lun_reset(
 366         struct se_device *dev,
 367         struct se_tmr_req *tmr,
 368         struct list_head *preempt_and_abort_list,
 369         struct se_cmd *prout_cmd)
 370 {
 371         struct se_node_acl *tmr_nacl = NULL;
 372         struct se_portal_group *tmr_tpg = NULL;
 373         struct se_session *tmr_sess = NULL;
 374         bool tas;
 375         /*
 376          * TASK_ABORTED status bit, this is configurable via ConfigFS
 377          * struct se_device attributes.  spc4r17 section 7.4.6 Control mode page
 378          *
 379          * A task aborted status (TAS) bit set to zero specifies that aborted
 380          * tasks shall be terminated by the device server without any response
 381          * to the application client. A TAS bit set to one specifies that tasks
 382          * aborted by the actions of an I_T nexus other than the I_T nexus on
 383          * which the command was received shall be completed with TASK ABORTED
 384          * status (see SAM-4).
 385          */
 386         tas = dev->dev_attrib.emulate_tas;
 387         /*
 388          * Determine if this se_tmr is coming from a $FABRIC_MOD
 389          * or struct se_device passthrough..
 390          */
 391         if (tmr && tmr->task_cmd && tmr->task_cmd->se_sess) {
 392                 tmr_sess = tmr->task_cmd->se_sess;
 393                 tmr_nacl = tmr_sess->se_node_acl;
 394                 tmr_tpg = tmr_sess->se_tpg;
 395                 if (tmr_nacl && tmr_tpg) {
 396                         pr_debug("LUN_RESET: TMR caller fabric: %s"
 397                                 " initiator port %s\n",
 398                                 tmr_tpg->se_tpg_tfo->fabric_name,
 399                                 tmr_nacl->initiatorname);
 400                 }
 401         }
 402
 403
 404         /*
 405          * We only allow one reset or preempt and abort to execute at a time
 406          * to prevent one call from claiming all the cmds causing a second
 407          * call from returning while cmds it should have waited on are still
 408          * running.
 409          */
 410         mutex_lock(&dev->lun_reset_mutex);
 411
 412         pr_debug("LUN_RESET: %s starting for [%s], tas: %d\n",
 413                 (preempt_and_abort_list) ? "Preempt" : "TMR",
 414                 dev->transport->name, tas);
 415         core_tmr_drain_tmr_list(dev, tmr, preempt_and_abort_list);
 416         core_tmr_drain_state_list(dev, prout_cmd, tmr_sess, tas,
 417                                 preempt_and_abort_list);
 418
 419         mutex_unlock(&dev->lun_reset_mutex);
 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->reservation_holder = 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