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
 125         spin_lock_irqsave(&dev->execute_task_lock, flags);
 126         list_for_each_entry_safe(se_cmd, next, &dev->state_list, state_list) {
 127
 128                 if (se_sess != se_cmd->se_sess)
 129                         continue;
 130
 131                 /* skip task management functions, including tmr->task_cmd */
 132                 if (se_cmd->se_cmd_flags & SCF_SCSI_TMR_CDB)
 133                         continue;
 134
 135                 ref_tag = se_cmd->tag;
 136                 if (tmr->ref_task_tag != ref_tag)
 137                         continue;
 138
 139                 printk("ABORT_TASK: Found referenced %s task_tag: %llu\n",
 140                         se_cmd->se_tfo->fabric_name, ref_tag);
 141
 142                 spin_lock(&se_sess->sess_cmd_lock);
 143                 rc = __target_check_io_state(se_cmd, se_sess, 0);
 144                 spin_unlock(&se_sess->sess_cmd_lock);
 145                 if (!rc)
 146                         continue;
 147
 148                 list_move_tail(&se_cmd->state_list, &aborted_list);
 149                 se_cmd->state_active = false;
 150
 151                 spin_unlock_irqrestore(&dev->execute_task_lock, flags);
 152
 153                 /*
 154                  * Ensure that this ABORT request is visible to the LU RESET
 155                  * code.
 156                  */
 157                 if (!tmr->tmr_dev)
 158                         WARN_ON_ONCE(transport_lookup_tmr_lun(tmr->task_cmd) <
 159                                         0);
 160
 161                 if (dev->transport->tmr_notify)
 162                         dev->transport->tmr_notify(dev, TMR_ABORT_TASK,
 163                                                    &aborted_list);
 164
 165                 list_del_init(&se_cmd->state_list);
 166                 target_put_cmd_and_wait(se_cmd);
 167
 168                 printk("ABORT_TASK: Sending TMR_FUNCTION_COMPLETE for"
 169                                 " ref_tag: %llu\n", ref_tag);
 170                 tmr->response = TMR_FUNCTION_COMPLETE;
 171                 atomic_long_inc(&dev->aborts_complete);
 172                 return;
 173         }
 174         spin_unlock_irqrestore(&dev->execute_task_lock, flags);
 175
 176         if (dev->transport->tmr_notify)
 177                 dev->transport->tmr_notify(dev, TMR_ABORT_TASK, &aborted_list);
 178
 179         printk("ABORT_TASK: Sending TMR_TASK_DOES_NOT_EXIST for ref_tag: %lld\n",
 180                         tmr->ref_task_tag);
 181         tmr->response = TMR_TASK_DOES_NOT_EXIST;
 182         atomic_long_inc(&dev->aborts_no_task);
 183 }
 184
 185 static void core_tmr_drain_tmr_list(
 186         struct se_device *dev,
 187         struct se_tmr_req *tmr,
 188         struct list_head *preempt_and_abort_list)
 189 {
 190         LIST_HEAD(drain_tmr_list);
 191         struct se_session *sess;
 192         struct se_tmr_req *tmr_p, *tmr_pp;
 193         struct se_cmd *cmd;
 194         unsigned long flags;
 195         bool rc;
 196         /*
 197          * Release all pending and outgoing TMRs aside from the received
 198          * LUN_RESET tmr..
 199          */
 200         spin_lock_irqsave(&dev->se_tmr_lock, flags);
 201         if (tmr)
 202                 list_del_init(&tmr->tmr_list);
 203         list_for_each_entry_safe(tmr_p, tmr_pp, &dev->dev_tmr_list, tmr_list) {
 204                 cmd = tmr_p->task_cmd;
 205                 if (!cmd) {
 206                         pr_err("Unable to locate struct se_cmd for TMR\n");
 207                         continue;
 208                 }
 209                 /*
 210                  * If this function was called with a valid pr_res_key
 211                  * parameter (eg: for PROUT PREEMPT_AND_ABORT service action
 212                  * skip non registration key matching TMRs.
 213                  */
 214                 if (target_check_cdb_and_preempt(preempt_and_abort_list, cmd))
 215                         continue;
 216
 217                 sess = cmd->se_sess;
 218                 if (WARN_ON_ONCE(!sess))
 219                         continue;
 220
 221                 spin_lock(&sess->sess_cmd_lock);
 222                 rc = __target_check_io_state(cmd, sess, 0);
 223                 spin_unlock(&sess->sess_cmd_lock);
 224
 225                 if (!rc) {
 226                         printk("LUN_RESET TMR: non-zero kref_get_unless_zero\n");
 227                         continue;
 228                 }
 229
 230                 list_move_tail(&tmr_p->tmr_list, &drain_tmr_list);
 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;
 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         spin_lock_irqsave(&dev->execute_task_lock, flags);
 301         list_for_each_entry_safe(cmd, next, &dev->state_list, state_list) {
 302                 /*
 303                  * For PREEMPT_AND_ABORT usage, only process commands
 304                  * with a matching reservation key.
 305                  */
 306                 if (target_check_cdb_and_preempt(preempt_and_abort_list, cmd))
 307                         continue;
 308
 309                 /*
 310                  * Not aborting PROUT PREEMPT_AND_ABORT CDB..
 311                  */
 312                 if (prout_cmd == cmd)
 313                         continue;
 314
 315                 sess = cmd->se_sess;
 316                 if (WARN_ON_ONCE(!sess))
 317                         continue;
 318
 319                 spin_lock(&sess->sess_cmd_lock);
 320                 rc = __target_check_io_state(cmd, tmr_sess, tas);
 321                 spin_unlock(&sess->sess_cmd_lock);
 322                 if (!rc)
 323                         continue;
 324
 325                 list_move_tail(&cmd->state_list, &drain_task_list);
 326                 cmd->state_active = false;
 327         }
 328         spin_unlock_irqrestore(&dev->execute_task_lock, flags);
 329
 330         if (dev->transport->tmr_notify)
 331                 dev->transport->tmr_notify(dev, preempt_and_abort_list ?
 332                                            TMR_LUN_RESET_PRO : TMR_LUN_RESET,
 333                                            &drain_task_list);
 334
 335         while (!list_empty(&drain_task_list)) {
 336                 cmd = list_entry(drain_task_list.next, struct se_cmd, state_list);
 337                 list_del_init(&cmd->state_list);
 338
 339                 target_show_cmd("LUN_RESET: ", cmd);
 340                 pr_debug("LUN_RESET: ITT[0x%08llx] - %s pr_res_key: 0x%016Lx\n",
 341                          cmd->tag, (preempt_and_abort_list) ? "preempt" : "",
 342                          cmd->pr_res_key);
 343
 344                 target_put_cmd_and_wait(cmd);
 345         }
 346 }
 347
 348 int core_tmr_lun_reset(
 349         struct se_device *dev,
 350         struct se_tmr_req *tmr,
 351         struct list_head *preempt_and_abort_list,
 352         struct se_cmd *prout_cmd)
 353 {
 354         struct se_node_acl *tmr_nacl = NULL;
 355         struct se_portal_group *tmr_tpg = NULL;
 356         struct se_session *tmr_sess = NULL;
 357         bool tas;
 358         /*
 359          * TASK_ABORTED status bit, this is configurable via ConfigFS
 360          * struct se_device attributes.  spc4r17 section 7.4.6 Control mode page
 361          *
 362          * A task aborted status (TAS) bit set to zero specifies that aborted
 363          * tasks shall be terminated by the device server without any response
 364          * to the application client. A TAS bit set to one specifies that tasks
 365          * aborted by the actions of an I_T nexus other than the I_T nexus on
 366          * which the command was received shall be completed with TASK ABORTED
 367          * status (see SAM-4).
 368          */
 369         tas = dev->dev_attrib.emulate_tas;
 370         /*
 371          * Determine if this se_tmr is coming from a $FABRIC_MOD
 372          * or struct se_device passthrough..
 373          */
 374         if (tmr && tmr->task_cmd && tmr->task_cmd->se_sess) {
 375                 tmr_sess = tmr->task_cmd->se_sess;
 376                 tmr_nacl = tmr_sess->se_node_acl;
 377                 tmr_tpg = tmr_sess->se_tpg;
 378                 if (tmr_nacl && tmr_tpg) {
 379                         pr_debug("LUN_RESET: TMR caller fabric: %s"
 380                                 " initiator port %s\n",
 381                                 tmr_tpg->se_tpg_tfo->fabric_name,
 382                                 tmr_nacl->initiatorname);
 383                 }
 384         }
 385         pr_debug("LUN_RESET: %s starting for [%s], tas: %d\n",
 386                 (preempt_and_abort_list) ? "Preempt" : "TMR",
 387                 dev->transport->name, tas);
 388
 389         core_tmr_drain_tmr_list(dev, tmr, preempt_and_abort_list);
 390         core_tmr_drain_state_list(dev, prout_cmd, tmr_sess, tas,
 391                                 preempt_and_abort_list);
 392
 393         /*
 394          * Clear any legacy SPC-2 reservation when called during
 395          * LOGICAL UNIT RESET
 396          */
 397         if (!preempt_and_abort_list &&
 398              (dev->dev_reservation_flags & DRF_SPC2_RESERVATIONS)) {
 399                 spin_lock(&dev->dev_reservation_lock);
 400                 dev->reservation_holder = NULL;
 401                 dev->dev_reservation_flags &= ~DRF_SPC2_RESERVATIONS;
 402                 spin_unlock(&dev->dev_reservation_lock);
 403                 pr_debug("LUN_RESET: SCSI-2 Released reservation\n");
 404         }
 405
 406         atomic_long_inc(&dev->num_resets);
 407
 408         pr_debug("LUN_RESET: %s for [%s] Complete\n",
 409                         (preempt_and_abort_list) ? "Preempt" : "TMR",
 410                         dev->transport->name);
 411         return 0;
 412 }
 413