drivers/target/target_core_tmr.c

   1 /*******************************************************************************
   2  * Filename:  target_core_tmr.c
   3  *
   4  * This file contains SPC-3 task management infrastructure
   5  *
   6  * (c) Copyright 2009-2013 Datera, Inc.
   7  *
   8  * Nicholas A. Bellinger <nab@kernel.org>
   9  *
  10  * This program is free software; you can redistribute it and/or modify
  11  * it under the terms of the GNU General Public License as published by
  12  * the Free Software Foundation; either version 2 of the License, or
  13  * (at your option) any later version.
  14  *
  15  * This program is distributed in the hope that it will be useful,
  16  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  17  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  18  * GNU General Public License for more details.
  19  *
  20  * You should have received a copy of the GNU General Public License
  21  * along with this program; if not, write to the Free Software
  22  * Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
  23  *
  24  ******************************************************************************/
  25
  26 #include <linux/slab.h>
  27 #include <linux/spinlock.h>
  28 #include <linux/list.h>
  29 #include <linux/export.h>
  30
  31 #include <target/target_core_base.h>
  32 #include <target/target_core_backend.h>
  33 #include <target/target_core_fabric.h>
  34
  35 #include "target_core_internal.h"
  36 #include "target_core_alua.h"
  37 #include "target_core_pr.h"
  38
  39 int core_tmr_alloc_req(
  40         struct se_cmd *se_cmd,
  41         void *fabric_tmr_ptr,
  42         u8 function,
  43         gfp_t gfp_flags)
  44 {
  45         struct se_tmr_req *tmr;
  46
  47         tmr = kzalloc(sizeof(struct se_tmr_req), gfp_flags);
  48         if (!tmr) {
  49                 pr_err("Unable to allocate struct se_tmr_req\n");
  50                 return -ENOMEM;
  51         }
  52
  53         se_cmd->se_cmd_flags |= SCF_SCSI_TMR_CDB;
  54         se_cmd->se_tmr_req = tmr;
  55         tmr->task_cmd = se_cmd;
  56         tmr->fabric_tmr_ptr = fabric_tmr_ptr;
  57         tmr->function = function;
  58         INIT_LIST_HEAD(&tmr->tmr_list);
  59
  60         return 0;
  61 }
  62 EXPORT_SYMBOL(core_tmr_alloc_req);
  63
  64 void core_tmr_release_req(struct se_tmr_req *tmr)
  65 {
  66         struct se_device *dev = tmr->tmr_dev;
  67         unsigned long flags;
  68
  69         if (dev) {
  70                 spin_lock_irqsave(&dev->se_tmr_lock, flags);
  71                 list_del(&tmr->tmr_list);
  72                 spin_unlock_irqrestore(&dev->se_tmr_lock, flags);
  73         }
  74
  75         kfree(tmr);
  76 }
  77
  78 static void core_tmr_handle_tas_abort(
  79         struct se_node_acl *tmr_nacl,
  80         struct se_cmd *cmd,
  81         int tas)
  82 {
  83         bool remove = true;
  84         /*
  85          * TASK ABORTED status (TAS) bit support
  86          */
  87         if ((tmr_nacl && (tmr_nacl != cmd->se_sess->se_node_acl)) && tas) {
  88                 remove = false;
  89                 transport_send_task_abort(cmd);
  90         }
  91
  92         transport_cmd_finish_abort(cmd, remove);
  93 }
  94
  95 static int target_check_cdb_and_preempt(struct list_head *list,
  96                 struct se_cmd *cmd)
  97 {
  98         struct t10_pr_registration *reg;
  99
 100         if (!list)
 101                 return 0;
 102         list_for_each_entry(reg, list, pr_reg_abort_list) {
 103                 if (reg->pr_res_key == cmd->pr_res_key)
 104                         return 0;
 105         }
 106
 107         return 1;
 108 }
 109
 110 static bool __target_check_io_state(struct se_cmd *se_cmd)
 111 {
 112         struct se_session *sess = se_cmd->se_sess;
 113
 114         assert_spin_locked(&sess->sess_cmd_lock);
 115         WARN_ON_ONCE(!irqs_disabled());
 116         /*
 117          * If command already reached CMD_T_COMPLETE state within
 118          * target_complete_cmd(), this se_cmd has been passed to
 119          * fabric driver and will not be aborted.
 120          *
 121          * Otherwise, obtain a local se_cmd->cmd_kref now for TMR
 122          * ABORT_TASK + LUN_RESET for CMD_T_ABORTED processing as
 123          * long as se_cmd->cmd_kref is still active unless zero.
 124          */
 125         spin_lock(&se_cmd->t_state_lock);
 126         if (se_cmd->transport_state & CMD_T_COMPLETE) {
 127                 pr_debug("Attempted to abort io tag: %llu already complete,"
 128                         " skipping\n", se_cmd->tag);
 129                 spin_unlock(&se_cmd->t_state_lock);
 130                 return false;
 131         }
 132         se_cmd->transport_state |= CMD_T_ABORTED;
 133         spin_unlock(&se_cmd->t_state_lock);
 134
 135         return kref_get_unless_zero(&se_cmd->cmd_kref);
 136 }
 137
 138 void core_tmr_abort_task(
 139         struct se_device *dev,
 140         struct se_tmr_req *tmr,
 141         struct se_session *se_sess)
 142 {
 143         struct se_cmd *se_cmd;
 144         unsigned long flags;
 145         u64 ref_tag;
 146
 147         spin_lock_irqsave(&se_sess->sess_cmd_lock, flags);
 148         list_for_each_entry(se_cmd, &se_sess->sess_cmd_list, se_cmd_list) {
 149
 150                 if (dev != se_cmd->se_dev)
 151                         continue;
 152
 153                 /* skip task management functions, including tmr->task_cmd */
 154                 if (se_cmd->se_cmd_flags & SCF_SCSI_TMR_CDB)
 155                         continue;
 156
 157                 ref_tag = se_cmd->tag;
 158                 if (tmr->ref_task_tag != ref_tag)
 159                         continue;
 160
 161                 printk("ABORT_TASK: Found referenced %s task_tag: %llu\n",
 162                         se_cmd->se_tfo->get_fabric_name(), ref_tag);
 163
 164                 if (!__target_check_io_state(se_cmd)) {
 165                         spin_unlock_irqrestore(&se_sess->sess_cmd_lock, flags);
 166                         target_put_sess_cmd(se_cmd);
 167                         goto out;
 168                 }
 169                 list_del_init(&se_cmd->se_cmd_list);
 170                 spin_unlock_irqrestore(&se_sess->sess_cmd_lock, flags);
 171
 172                 cancel_work_sync(&se_cmd->work);
 173                 transport_wait_for_tasks(se_cmd);
 174
 175                 transport_cmd_finish_abort(se_cmd, true);
 176                 target_put_sess_cmd(se_cmd);
 177
 178                 printk("ABORT_TASK: Sending TMR_FUNCTION_COMPLETE for"
 179                                 " ref_tag: %llu\n", ref_tag);
 180                 tmr->response = TMR_FUNCTION_COMPLETE;
 181                 return;
 182         }
 183         spin_unlock_irqrestore(&se_sess->sess_cmd_lock, flags);
 184
 185 out:
 186         printk("ABORT_TASK: Sending TMR_TASK_DOES_NOT_EXIST for ref_tag: %lld\n",
 187                         tmr->ref_task_tag);
 188         tmr->response = TMR_TASK_DOES_NOT_EXIST;
 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_tmr_req *tmr_p, *tmr_pp;
 198         struct se_cmd *cmd;
 199         unsigned long flags;
 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                 /*
 207                  * Allow the received TMR to return with FUNCTION_COMPLETE.
 208                  */
 209                 if (tmr_p == tmr)
 210                         continue;
 211
 212                 cmd = tmr_p->task_cmd;
 213                 if (!cmd) {
 214                         pr_err("Unable to locate struct se_cmd for TMR\n");
 215                         continue;
 216                 }
 217                 /*
 218                  * If this function was called with a valid pr_res_key
 219                  * parameter (eg: for PROUT PREEMPT_AND_ABORT service action
 220                  * skip non registration key matching TMRs.
 221                  */
 222                 if (target_check_cdb_and_preempt(preempt_and_abort_list, cmd))
 223                         continue;
 224
 225                 spin_lock(&cmd->t_state_lock);
 226                 if (!(cmd->transport_state & CMD_T_ACTIVE)) {
 227                         spin_unlock(&cmd->t_state_lock);
 228                         continue;
 229                 }
 230                 if (cmd->t_state == TRANSPORT_ISTATE_PROCESSING) {
 231                         spin_unlock(&cmd->t_state_lock);
 232                         continue;
 233                 }
 234                 spin_unlock(&cmd->t_state_lock);
 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                 transport_cmd_finish_abort(cmd, 1);
 250         }
 251 }
 252
 253 static void core_tmr_drain_state_list(
 254         struct se_device *dev,
 255         struct se_cmd *prout_cmd,
 256         struct se_node_acl *tmr_nacl,
 257         int tas,
 258         struct list_head *preempt_and_abort_list)
 259 {
 260         LIST_HEAD(drain_task_list);
 261         struct se_session *sess;
 262         struct se_cmd *cmd, *next;
 263         unsigned long flags;
 264         int rc;
 265
 266         /*
 267          * Complete outstanding commands with TASK_ABORTED SAM status.
 268          *
 269          * This is following sam4r17, section 5.6 Aborting commands, Table 38
 270          * for TMR LUN_RESET:
 271          *
 272          * a) "Yes" indicates that each command that is aborted on an I_T nexus
 273          * other than the one that caused the SCSI device condition is
 274          * completed with TASK ABORTED status, if the TAS bit is set to one in
 275          * the Control mode page (see SPC-4). "No" indicates that no status is
 276          * returned for aborted commands.
 277          *
 278          * d) If the logical unit reset is caused by a particular I_T nexus
 279          * (e.g., by a LOGICAL UNIT RESET task management function), then "yes"
 280          * (TASK_ABORTED status) applies.
 281          *
 282          * Otherwise (e.g., if triggered by a hard reset), "no"
 283          * (no TASK_ABORTED SAM status) applies.
 284          *
 285          * Note that this seems to be independent of TAS (Task Aborted Status)
 286          * in the Control Mode Page.
 287          */
 288         spin_lock_irqsave(&dev->execute_task_lock, flags);
 289         list_for_each_entry_safe(cmd, next, &dev->state_list, state_list) {
 290                 /*
 291                  * For PREEMPT_AND_ABORT usage, only process commands
 292                  * with a matching reservation key.
 293                  */
 294                 if (target_check_cdb_and_preempt(preempt_and_abort_list, cmd))
 295                         continue;
 296
 297                 /*
 298                  * Not aborting PROUT PREEMPT_AND_ABORT CDB..
 299                  */
 300                 if (prout_cmd == cmd)
 301                         continue;
 302
 303                 sess = cmd->se_sess;
 304                 if (WARN_ON_ONCE(!sess))
 305                         continue;
 306
 307                 spin_lock(&sess->sess_cmd_lock);
 308                 rc = __target_check_io_state(cmd);
 309                 spin_unlock(&sess->sess_cmd_lock);
 310                 if (!rc)
 311                         continue;
 312
 313                 list_move_tail(&cmd->state_list, &drain_task_list);
 314                 cmd->state_active = false;
 315         }
 316         spin_unlock_irqrestore(&dev->execute_task_lock, flags);
 317
 318         while (!list_empty(&drain_task_list)) {
 319                 cmd = list_entry(drain_task_list.next, struct se_cmd, state_list);
 320                 list_del_init(&cmd->state_list);
 321
 322                 pr_debug("LUN_RESET: %s cmd: %p"
 323                         " ITT/CmdSN: 0x%08llx/0x%08x, i_state: %d, t_state: %d"
 324                         "cdb: 0x%02x\n",
 325                         (preempt_and_abort_list) ? "Preempt" : "", cmd,
 326                         cmd->tag, 0,
 327                         cmd->se_tfo->get_cmd_state(cmd), cmd->t_state,
 328                         cmd->t_task_cdb[0]);
 329                 pr_debug("LUN_RESET: ITT[0x%08llx] - pr_res_key: 0x%016Lx"
 330                         " -- CMD_T_ACTIVE: %d"
 331                         " CMD_T_STOP: %d CMD_T_SENT: %d\n",
 332                         cmd->tag, cmd->pr_res_key,
 333                         (cmd->transport_state & CMD_T_ACTIVE) != 0,
 334                         (cmd->transport_state & CMD_T_STOP) != 0,
 335                         (cmd->transport_state & CMD_T_SENT) != 0);
 336
 337                 /*
 338                  * If the command may be queued onto a workqueue cancel it now.
 339                  *
 340                  * This is equivalent to removal from the execute queue in the
 341                  * loop above, but we do it down here given that
 342                  * cancel_work_sync may block.
 343                  */
 344                 cancel_work_sync(&cmd->work);
 345                 transport_wait_for_tasks(cmd);
 346
 347                 core_tmr_handle_tas_abort(tmr_nacl, cmd, tas);
 348                 target_put_sess_cmd(cmd);
 349         }
 350 }
 351
 352 int core_tmr_lun_reset(
 353         struct se_device *dev,
 354         struct se_tmr_req *tmr,
 355         struct list_head *preempt_and_abort_list,
 356         struct se_cmd *prout_cmd)
 357 {
 358         struct se_node_acl *tmr_nacl = NULL;
 359         struct se_portal_group *tmr_tpg = NULL;
 360         int tas;
 361         /*
 362          * TASK_ABORTED status bit, this is configurable via ConfigFS
 363          * struct se_device attributes.  spc4r17 section 7.4.6 Control mode page
 364          *
 365          * A task aborted status (TAS) bit set to zero specifies that aborted
 366          * tasks shall be terminated by the device server without any response
 367          * to the application client. A TAS bit set to one specifies that tasks
 368          * aborted by the actions of an I_T nexus other than the I_T nexus on
 369          * which the command was received shall be completed with TASK ABORTED
 370          * status (see SAM-4).
 371          */
 372         tas = dev->dev_attrib.emulate_tas;
 373         /*
 374          * Determine if this se_tmr is coming from a $FABRIC_MOD
 375          * or struct se_device passthrough..
 376          */
 377         if (tmr && tmr->task_cmd && tmr->task_cmd->se_sess) {
 378                 tmr_nacl = tmr->task_cmd->se_sess->se_node_acl;
 379                 tmr_tpg = tmr->task_cmd->se_sess->se_tpg;
 380                 if (tmr_nacl && tmr_tpg) {
 381                         pr_debug("LUN_RESET: TMR caller fabric: %s"
 382                                 " initiator port %s\n",
 383                                 tmr_tpg->se_tpg_tfo->get_fabric_name(),
 384                                 tmr_nacl->initiatorname);
 385                 }
 386         }
 387         pr_debug("LUN_RESET: %s starting for [%s], tas: %d\n",
 388                 (preempt_and_abort_list) ? "Preempt" : "TMR",
 389                 dev->transport->name, tas);
 390
 391         core_tmr_drain_tmr_list(dev, tmr, preempt_and_abort_list);
 392         core_tmr_drain_state_list(dev, prout_cmd, tmr_nacl, tas,
 393                                 preempt_and_abort_list);
 394
 395         /*
 396          * Clear any legacy SPC-2 reservation when called during
 397          * LOGICAL UNIT RESET
 398          */
 399         if (!preempt_and_abort_list &&
 400              (dev->dev_reservation_flags & DRF_SPC2_RESERVATIONS)) {
 401                 spin_lock(&dev->dev_reservation_lock);
 402                 dev->dev_reserved_node_acl = NULL;
 403                 dev->dev_reservation_flags &= ~DRF_SPC2_RESERVATIONS;
 404                 spin_unlock(&dev->dev_reservation_lock);
 405                 pr_debug("LUN_RESET: SCSI-2 Released reservation\n");
 406         }
 407
 408         atomic_long_inc(&dev->num_resets);
 409
 410         pr_debug("LUN_RESET: %s for [%s] Complete\n",
 411                         (preempt_and_abort_list) ? "Preempt" : "TMR",
 412                         dev->transport->name);
 413         return 0;
 414 }
 415