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                 printk("ABORT_TASK: Found referenced %s task_tag: %llu\n",
 134                         se_cmd->se_tfo->get_fabric_name(), ref_tag);
 135
 136                 spin_lock(&se_cmd->t_state_lock);
 137                 if (se_cmd->transport_state & CMD_T_COMPLETE) {
 138                         printk("ABORT_TASK: ref_tag: %llu already complete,"
 139                                " skipping\n", ref_tag);
 140                         spin_unlock(&se_cmd->t_state_lock);
 141                         spin_unlock_irqrestore(&se_sess->sess_cmd_lock, flags);
 142                         goto out;
 143                 }
 144                 se_cmd->transport_state |= CMD_T_ABORTED;
 145                 spin_unlock(&se_cmd->t_state_lock);
 146
 147                 list_del_init(&se_cmd->se_cmd_list);
 148                 kref_get(&se_cmd->cmd_kref);
 149                 spin_unlock_irqrestore(&se_sess->sess_cmd_lock, flags);
 150
 151                 cancel_work_sync(&se_cmd->work);
 152                 transport_wait_for_tasks(se_cmd);
 153
 154                 target_put_sess_cmd(se_cmd);
 155                 transport_cmd_finish_abort(se_cmd, true);
 156
 157                 printk("ABORT_TASK: Sending TMR_FUNCTION_COMPLETE for"
 158                                 " ref_tag: %llu\n", ref_tag);
 159                 tmr->response = TMR_FUNCTION_COMPLETE;
 160                 return;
 161         }
 162         spin_unlock_irqrestore(&se_sess->sess_cmd_lock, flags);
 163
 164 out:
 165         printk("ABORT_TASK: Sending TMR_TASK_DOES_NOT_EXIST for ref_tag: %lld\n",
 166                         tmr->ref_task_tag);
 167         tmr->response = TMR_TASK_DOES_NOT_EXIST;
 168 }
 169
 170 static void core_tmr_drain_tmr_list(
 171         struct se_device *dev,
 172         struct se_tmr_req *tmr,
 173         struct list_head *preempt_and_abort_list)
 174 {
 175         LIST_HEAD(drain_tmr_list);
 176         struct se_tmr_req *tmr_p, *tmr_pp;
 177         struct se_cmd *cmd;
 178         unsigned long flags;
 179         /*
 180          * Release all pending and outgoing TMRs aside from the received
 181          * LUN_RESET tmr..
 182          */
 183         spin_lock_irqsave(&dev->se_tmr_lock, flags);
 184         list_for_each_entry_safe(tmr_p, tmr_pp, &dev->dev_tmr_list, tmr_list) {
 185                 /*
 186                  * Allow the received TMR to return with FUNCTION_COMPLETE.
 187                  */
 188                 if (tmr_p == tmr)
 189                         continue;
 190
 191                 cmd = tmr_p->task_cmd;
 192                 if (!cmd) {
 193                         pr_err("Unable to locate struct se_cmd for TMR\n");
 194                         continue;
 195                 }
 196                 /*
 197                  * If this function was called with a valid pr_res_key
 198                  * parameter (eg: for PROUT PREEMPT_AND_ABORT service action
 199                  * skip non regisration key matching TMRs.
 200                  */
 201                 if (target_check_cdb_and_preempt(preempt_and_abort_list, cmd))
 202                         continue;
 203
 204                 spin_lock(&cmd->t_state_lock);
 205                 if (!(cmd->transport_state & CMD_T_ACTIVE)) {
 206                         spin_unlock(&cmd->t_state_lock);
 207                         continue;
 208                 }
 209                 if (cmd->t_state == TRANSPORT_ISTATE_PROCESSING) {
 210                         spin_unlock(&cmd->t_state_lock);
 211                         continue;
 212                 }
 213                 spin_unlock(&cmd->t_state_lock);
 214
 215                 list_move_tail(&tmr_p->tmr_list, &drain_tmr_list);
 216         }
 217         spin_unlock_irqrestore(&dev->se_tmr_lock, flags);
 218
 219         list_for_each_entry_safe(tmr_p, tmr_pp, &drain_tmr_list, tmr_list) {
 220                 list_del_init(&tmr_p->tmr_list);
 221                 cmd = tmr_p->task_cmd;
 222
 223                 pr_debug("LUN_RESET: %s releasing TMR %p Function: 0x%02x,"
 224                         " Response: 0x%02x, t_state: %d\n",
 225                         (preempt_and_abort_list) ? "Preempt" : "", tmr_p,
 226                         tmr_p->function, tmr_p->response, cmd->t_state);
 227
 228                 transport_cmd_finish_abort(cmd, 1);
 229         }
 230 }
 231
 232 static void core_tmr_drain_state_list(
 233         struct se_device *dev,
 234         struct se_cmd *prout_cmd,
 235         struct se_node_acl *tmr_nacl,
 236         int tas,
 237         struct list_head *preempt_and_abort_list)
 238 {
 239         LIST_HEAD(drain_task_list);
 240         struct se_cmd *cmd, *next;
 241         unsigned long flags;
 242
 243         /*
 244          * Complete outstanding commands with TASK_ABORTED SAM status.
 245          *
 246          * This is following sam4r17, section 5.6 Aborting commands, Table 38
 247          * for TMR LUN_RESET:
 248          *
 249          * a) "Yes" indicates that each command that is aborted on an I_T nexus
 250          * other than the one that caused the SCSI device condition is
 251          * completed with TASK ABORTED status, if the TAS bit is set to one in
 252          * the Control mode page (see SPC-4). "No" indicates that no status is
 253          * returned for aborted commands.
 254          *
 255          * d) If the logical unit reset is caused by a particular I_T nexus
 256          * (e.g., by a LOGICAL UNIT RESET task management function), then "yes"
 257          * (TASK_ABORTED status) applies.
 258          *
 259          * Otherwise (e.g., if triggered by a hard reset), "no"
 260          * (no TASK_ABORTED SAM status) applies.
 261          *
 262          * Note that this seems to be independent of TAS (Task Aborted Status)
 263          * in the Control Mode Page.
 264          */
 265         spin_lock_irqsave(&dev->execute_task_lock, flags);
 266         list_for_each_entry_safe(cmd, next, &dev->state_list, state_list) {
 267                 /*
 268                  * For PREEMPT_AND_ABORT usage, only process commands
 269                  * with a matching reservation key.
 270                  */
 271                 if (target_check_cdb_and_preempt(preempt_and_abort_list, cmd))
 272                         continue;
 273
 274                 /*
 275                  * Not aborting PROUT PREEMPT_AND_ABORT CDB..
 276                  */
 277                 if (prout_cmd == cmd)
 278                         continue;
 279
 280                 list_move_tail(&cmd->state_list, &drain_task_list);
 281                 cmd->state_active = false;
 282         }
 283         spin_unlock_irqrestore(&dev->execute_task_lock, flags);
 284
 285         while (!list_empty(&drain_task_list)) {
 286                 cmd = list_entry(drain_task_list.next, struct se_cmd, state_list);
 287                 list_del(&cmd->state_list);
 288
 289                 pr_debug("LUN_RESET: %s cmd: %p"
 290                         " ITT/CmdSN: 0x%08llx/0x%08x, i_state: %d, t_state: %d"
 291                         "cdb: 0x%02x\n",
 292                         (preempt_and_abort_list) ? "Preempt" : "", cmd,
 293                         cmd->tag, 0,
 294                         cmd->se_tfo->get_cmd_state(cmd), cmd->t_state,
 295                         cmd->t_task_cdb[0]);
 296                 pr_debug("LUN_RESET: ITT[0x%08llx] - pr_res_key: 0x%016Lx"
 297                         " -- CMD_T_ACTIVE: %d"
 298                         " CMD_T_STOP: %d CMD_T_SENT: %d\n",
 299                         cmd->tag, cmd->pr_res_key,
 300                         (cmd->transport_state & CMD_T_ACTIVE) != 0,
 301                         (cmd->transport_state & CMD_T_STOP) != 0,
 302                         (cmd->transport_state & CMD_T_SENT) != 0);
 303
 304                 /*
 305                  * If the command may be queued onto a workqueue cancel it now.
 306                  *
 307                  * This is equivalent to removal from the execute queue in the
 308                  * loop above, but we do it down here given that
 309                  * cancel_work_sync may block.
 310                  */
 311                 if (cmd->t_state == TRANSPORT_COMPLETE)
 312                         cancel_work_sync(&cmd->work);
 313
 314                 spin_lock_irqsave(&cmd->t_state_lock, flags);
 315                 target_stop_cmd(cmd, &flags);
 316
 317                 cmd->transport_state |= CMD_T_ABORTED;
 318                 spin_unlock_irqrestore(&cmd->t_state_lock, flags);
 319
 320                 core_tmr_handle_tas_abort(tmr_nacl, cmd, tas);
 321         }
 322 }
 323
 324 int core_tmr_lun_reset(
 325         struct se_device *dev,
 326         struct se_tmr_req *tmr,
 327         struct list_head *preempt_and_abort_list,
 328         struct se_cmd *prout_cmd)
 329 {
 330         struct se_node_acl *tmr_nacl = NULL;
 331         struct se_portal_group *tmr_tpg = NULL;
 332         int tas;
 333         /*
 334          * TASK_ABORTED status bit, this is configurable via ConfigFS
 335          * struct se_device attributes.  spc4r17 section 7.4.6 Control mode page
 336          *
 337          * A task aborted status (TAS) bit set to zero specifies that aborted
 338          * tasks shall be terminated by the device server without any response
 339          * to the application client. A TAS bit set to one specifies that tasks
 340          * aborted by the actions of an I_T nexus other than the I_T nexus on
 341          * which the command was received shall be completed with TASK ABORTED
 342          * status (see SAM-4).
 343          */
 344         tas = dev->dev_attrib.emulate_tas;
 345         /*
 346          * Determine if this se_tmr is coming from a $FABRIC_MOD
 347          * or struct se_device passthrough..
 348          */
 349         if (tmr && tmr->task_cmd && tmr->task_cmd->se_sess) {
 350                 tmr_nacl = tmr->task_cmd->se_sess->se_node_acl;
 351                 tmr_tpg = tmr->task_cmd->se_sess->se_tpg;
 352                 if (tmr_nacl && tmr_tpg) {
 353                         pr_debug("LUN_RESET: TMR caller fabric: %s"
 354                                 " initiator port %s\n",
 355                                 tmr_tpg->se_tpg_tfo->get_fabric_name(),
 356                                 tmr_nacl->initiatorname);
 357                 }
 358         }
 359         pr_debug("LUN_RESET: %s starting for [%s], tas: %d\n",
 360                 (preempt_and_abort_list) ? "Preempt" : "TMR",
 361                 dev->transport->name, tas);
 362
 363         core_tmr_drain_tmr_list(dev, tmr, preempt_and_abort_list);
 364         core_tmr_drain_state_list(dev, prout_cmd, tmr_nacl, tas,
 365                                 preempt_and_abort_list);
 366
 367         /*
 368          * Clear any legacy SPC-2 reservation when called during
 369          * LOGICAL UNIT RESET
 370          */
 371         if (!preempt_and_abort_list &&
 372              (dev->dev_reservation_flags & DRF_SPC2_RESERVATIONS)) {
 373                 spin_lock(&dev->dev_reservation_lock);
 374                 dev->dev_reserved_node_acl = NULL;
 375                 dev->dev_reservation_flags &= ~DRF_SPC2_RESERVATIONS;
 376                 spin_unlock(&dev->dev_reservation_lock);
 377                 pr_debug("LUN_RESET: SCSI-2 Released reservation\n");
 378         }
 379
 380         atomic_long_inc(&dev->num_resets);
 381
 382         pr_debug("LUN_RESET: %s for [%s] Complete\n",
 383                         (preempt_and_abort_list) ? "Preempt" : "TMR",
 384                         dev->transport->name);
 385         return 0;
 386 }
 387