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 void core_tmr_abort_task(
 111         struct se_device *dev,
 112         struct se_tmr_req *tmr,
 113         struct se_session *se_sess)
 114 {
 115         struct se_cmd *se_cmd;
 116         unsigned long flags;
 117         u64 ref_tag;
 118
 119         spin_lock_irqsave(&se_sess->sess_cmd_lock, flags);
 120         list_for_each_entry(se_cmd, &se_sess->sess_cmd_list, se_cmd_list) {
 121
 122                 if (dev != se_cmd->se_dev)
 123                         continue;
 124
 125                 /* skip task management functions, including tmr->task_cmd */
 126                 if (se_cmd->se_cmd_flags & SCF_SCSI_TMR_CDB)
 127                         continue;
 128
 129                 ref_tag = se_cmd->tag;
 130                 if (tmr->ref_task_tag != ref_tag)
 131                         continue;
 132
 133                 if (!kref_get_unless_zero(&se_cmd->cmd_kref))
 134                         continue;
 135
 136                 printk("ABORT_TASK: Found referenced %s task_tag: %llu\n",
 137                         se_cmd->se_tfo->get_fabric_name(), ref_tag);
 138
 139                 spin_lock(&se_cmd->t_state_lock);
 140                 if (se_cmd->transport_state & CMD_T_COMPLETE) {
 141                         printk("ABORT_TASK: ref_tag: %llu already complete,"
 142                                " skipping\n", ref_tag);
 143                         spin_unlock(&se_cmd->t_state_lock);
 144                         spin_unlock_irqrestore(&se_sess->sess_cmd_lock, flags);
 145
 146                         target_put_sess_cmd(se_cmd);
 147
 148                         goto out;
 149                 }
 150                 se_cmd->transport_state |= CMD_T_ABORTED;
 151                 spin_unlock(&se_cmd->t_state_lock);
 152
 153                 list_del_init(&se_cmd->se_cmd_list);
 154                 spin_unlock_irqrestore(&se_sess->sess_cmd_lock, flags);
 155
 156                 cancel_work_sync(&se_cmd->work);
 157                 transport_wait_for_tasks(se_cmd);
 158
 159                 target_put_sess_cmd(se_cmd);
 160                 transport_cmd_finish_abort(se_cmd, true);
 161
 162                 printk("ABORT_TASK: Sending TMR_FUNCTION_COMPLETE for"
 163                                 " ref_tag: %llu\n", ref_tag);
 164                 tmr->response = TMR_FUNCTION_COMPLETE;
 165                 return;
 166         }
 167         spin_unlock_irqrestore(&se_sess->sess_cmd_lock, flags);
 168
 169 out:
 170         printk("ABORT_TASK: Sending TMR_TASK_DOES_NOT_EXIST for ref_tag: %lld\n",
 171                         tmr->ref_task_tag);
 172         tmr->response = TMR_TASK_DOES_NOT_EXIST;
 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_tmr_req *tmr_p, *tmr_pp;
 182         struct se_cmd *cmd;
 183         unsigned long flags;
 184         /*
 185          * Release all pending and outgoing TMRs aside from the received
 186          * LUN_RESET tmr..
 187          */
 188         spin_lock_irqsave(&dev->se_tmr_lock, flags);
 189         list_for_each_entry_safe(tmr_p, tmr_pp, &dev->dev_tmr_list, tmr_list) {
 190                 /*
 191                  * Allow the received TMR to return with FUNCTION_COMPLETE.
 192                  */
 193                 if (tmr_p == tmr)
 194                         continue;
 195
 196                 cmd = tmr_p->task_cmd;
 197                 if (!cmd) {
 198                         pr_err("Unable to locate struct se_cmd for TMR\n");
 199                         continue;
 200                 }
 201                 /*
 202                  * If this function was called with a valid pr_res_key
 203                  * parameter (eg: for PROUT PREEMPT_AND_ABORT service action
 204                  * skip non regisration key matching TMRs.
 205                  */
 206                 if (target_check_cdb_and_preempt(preempt_and_abort_list, cmd))
 207                         continue;
 208
 209                 spin_lock(&cmd->t_state_lock);
 210                 if (!(cmd->transport_state & CMD_T_ACTIVE)) {
 211                         spin_unlock(&cmd->t_state_lock);
 212                         continue;
 213                 }
 214                 if (cmd->t_state == TRANSPORT_ISTATE_PROCESSING) {
 215                         spin_unlock(&cmd->t_state_lock);
 216                         continue;
 217                 }
 218                 spin_unlock(&cmd->t_state_lock);
 219
 220                 list_move_tail(&tmr_p->tmr_list, &drain_tmr_list);
 221         }
 222         spin_unlock_irqrestore(&dev->se_tmr_lock, flags);
 223
 224         list_for_each_entry_safe(tmr_p, tmr_pp, &drain_tmr_list, tmr_list) {
 225                 list_del_init(&tmr_p->tmr_list);
 226                 cmd = tmr_p->task_cmd;
 227
 228                 pr_debug("LUN_RESET: %s releasing TMR %p Function: 0x%02x,"
 229                         " Response: 0x%02x, t_state: %d\n",
 230                         (preempt_and_abort_list) ? "Preempt" : "", tmr_p,
 231                         tmr_p->function, tmr_p->response, cmd->t_state);
 232
 233                 transport_cmd_finish_abort(cmd, 1);
 234         }
 235 }
 236
 237 static void core_tmr_drain_state_list(
 238         struct se_device *dev,
 239         struct se_cmd *prout_cmd,
 240         struct se_node_acl *tmr_nacl,
 241         int tas,
 242         struct list_head *preempt_and_abort_list)
 243 {
 244         LIST_HEAD(drain_task_list);
 245         struct se_cmd *cmd, *next;
 246         unsigned long flags;
 247
 248         /*
 249          * Complete outstanding commands with TASK_ABORTED SAM status.
 250          *
 251          * This is following sam4r17, section 5.6 Aborting commands, Table 38
 252          * for TMR LUN_RESET:
 253          *
 254          * a) "Yes" indicates that each command that is aborted on an I_T nexus
 255          * other than the one that caused the SCSI device condition is
 256          * completed with TASK ABORTED status, if the TAS bit is set to one in
 257          * the Control mode page (see SPC-4). "No" indicates that no status is
 258          * returned for aborted commands.
 259          *
 260          * d) If the logical unit reset is caused by a particular I_T nexus
 261          * (e.g., by a LOGICAL UNIT RESET task management function), then "yes"
 262          * (TASK_ABORTED status) applies.
 263          *
 264          * Otherwise (e.g., if triggered by a hard reset), "no"
 265          * (no TASK_ABORTED SAM status) applies.
 266          *
 267          * Note that this seems to be independent of TAS (Task Aborted Status)
 268          * in the Control Mode Page.
 269          */
 270         spin_lock_irqsave(&dev->execute_task_lock, flags);
 271         list_for_each_entry_safe(cmd, next, &dev->state_list, state_list) {
 272                 /*
 273                  * For PREEMPT_AND_ABORT usage, only process commands
 274                  * with a matching reservation key.
 275                  */
 276                 if (target_check_cdb_and_preempt(preempt_and_abort_list, cmd))
 277                         continue;
 278
 279                 /*
 280                  * Not aborting PROUT PREEMPT_AND_ABORT CDB..
 281                  */
 282                 if (prout_cmd == cmd)
 283                         continue;
 284
 285                 list_move_tail(&cmd->state_list, &drain_task_list);
 286                 cmd->state_active = false;
 287         }
 288         spin_unlock_irqrestore(&dev->execute_task_lock, flags);
 289
 290         while (!list_empty(&drain_task_list)) {
 291                 cmd = list_entry(drain_task_list.next, struct se_cmd, state_list);
 292                 list_del(&cmd->state_list);
 293
 294                 pr_debug("LUN_RESET: %s cmd: %p"
 295                         " ITT/CmdSN: 0x%08llx/0x%08x, i_state: %d, t_state: %d"
 296                         "cdb: 0x%02x\n",
 297                         (preempt_and_abort_list) ? "Preempt" : "", cmd,
 298                         cmd->tag, 0,
 299                         cmd->se_tfo->get_cmd_state(cmd), cmd->t_state,
 300                         cmd->t_task_cdb[0]);
 301                 pr_debug("LUN_RESET: ITT[0x%08llx] - pr_res_key: 0x%016Lx"
 302                         " -- CMD_T_ACTIVE: %d"
 303                         " CMD_T_STOP: %d CMD_T_SENT: %d\n",
 304                         cmd->tag, cmd->pr_res_key,
 305                         (cmd->transport_state & CMD_T_ACTIVE) != 0,
 306                         (cmd->transport_state & CMD_T_STOP) != 0,
 307                         (cmd->transport_state & CMD_T_SENT) != 0);
 308
 309                 /*
 310                  * If the command may be queued onto a workqueue cancel it now.
 311                  *
 312                  * This is equivalent to removal from the execute queue in the
 313                  * loop above, but we do it down here given that
 314                  * cancel_work_sync may block.
 315                  */
 316                 if (cmd->t_state == TRANSPORT_COMPLETE)
 317                         cancel_work_sync(&cmd->work);
 318
 319                 spin_lock_irqsave(&cmd->t_state_lock, flags);
 320                 target_stop_cmd(cmd, &flags);
 321
 322                 cmd->transport_state |= CMD_T_ABORTED;
 323                 spin_unlock_irqrestore(&cmd->t_state_lock, flags);
 324
 325                 core_tmr_handle_tas_abort(tmr_nacl, cmd, tas);
 326         }
 327 }
 328
 329 int core_tmr_lun_reset(
 330         struct se_device *dev,
 331         struct se_tmr_req *tmr,
 332         struct list_head *preempt_and_abort_list,
 333         struct se_cmd *prout_cmd)
 334 {
 335         struct se_node_acl *tmr_nacl = NULL;
 336         struct se_portal_group *tmr_tpg = NULL;
 337         int tas;
 338         /*
 339          * TASK_ABORTED status bit, this is configurable via ConfigFS
 340          * struct se_device attributes.  spc4r17 section 7.4.6 Control mode page
 341          *
 342          * A task aborted status (TAS) bit set to zero specifies that aborted
 343          * tasks shall be terminated by the device server without any response
 344          * to the application client. A TAS bit set to one specifies that tasks
 345          * aborted by the actions of an I_T nexus other than the I_T nexus on
 346          * which the command was received shall be completed with TASK ABORTED
 347          * status (see SAM-4).
 348          */
 349         tas = dev->dev_attrib.emulate_tas;
 350         /*
 351          * Determine if this se_tmr is coming from a $FABRIC_MOD
 352          * or struct se_device passthrough..
 353          */
 354         if (tmr && tmr->task_cmd && tmr->task_cmd->se_sess) {
 355                 tmr_nacl = tmr->task_cmd->se_sess->se_node_acl;
 356                 tmr_tpg = tmr->task_cmd->se_sess->se_tpg;
 357                 if (tmr_nacl && tmr_tpg) {
 358                         pr_debug("LUN_RESET: TMR caller fabric: %s"
 359                                 " initiator port %s\n",
 360                                 tmr_tpg->se_tpg_tfo->get_fabric_name(),
 361                                 tmr_nacl->initiatorname);
 362                 }
 363         }
 364         pr_debug("LUN_RESET: %s starting for [%s], tas: %d\n",
 365                 (preempt_and_abort_list) ? "Preempt" : "TMR",
 366                 dev->transport->name, tas);
 367
 368         core_tmr_drain_tmr_list(dev, tmr, preempt_and_abort_list);
 369         core_tmr_drain_state_list(dev, prout_cmd, tmr_nacl, tas,
 370                                 preempt_and_abort_list);
 371
 372         /*
 373          * Clear any legacy SPC-2 reservation when called during
 374          * LOGICAL UNIT RESET
 375          */
 376         if (!preempt_and_abort_list &&
 377              (dev->dev_reservation_flags & DRF_SPC2_RESERVATIONS)) {
 378                 spin_lock(&dev->dev_reservation_lock);
 379                 dev->dev_reserved_node_acl = NULL;
 380                 dev->dev_reservation_flags &= ~DRF_SPC2_RESERVATIONS;
 381                 spin_unlock(&dev->dev_reservation_lock);
 382                 pr_debug("LUN_RESET: SCSI-2 Released reservation\n");
 383         }
 384
 385         atomic_long_inc(&dev->num_resets);
 386
 387         pr_debug("LUN_RESET: %s for [%s] Complete\n",
 388                         (preempt_and_abort_list) ? "Preempt" : "TMR",
 389                         dev->transport->name);
 390         return 0;
 391 }
 392