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 2009-2012 RisingTide Systems LLC.
   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 #include <scsi/scsi.h>
  31 #include <scsi/scsi_cmnd.h>
  32
  33 #include <target/target_core_base.h>
  34 #include <target/target_core_backend.h>
  35 #include <target/target_core_fabric.h>
  36 #include <target/target_core_configfs.h>
  37
  38 #include "target_core_internal.h"
  39 #include "target_core_alua.h"
  40 #include "target_core_pr.h"
  41
  42 int core_tmr_alloc_req(
  43         struct se_cmd *se_cmd,
  44         void *fabric_tmr_ptr,
  45         u8 function,
  46         gfp_t gfp_flags)
  47 {
  48         struct se_tmr_req *tmr;
  49
  50         tmr = kzalloc(sizeof(struct se_tmr_req), gfp_flags);
  51         if (!tmr) {
  52                 pr_err("Unable to allocate struct se_tmr_req\n");
  53                 return -ENOMEM;
  54         }
  55
  56         se_cmd->se_cmd_flags |= SCF_SCSI_TMR_CDB;
  57         se_cmd->se_tmr_req = tmr;
  58         tmr->task_cmd = se_cmd;
  59         tmr->fabric_tmr_ptr = fabric_tmr_ptr;
  60         tmr->function = function;
  61         INIT_LIST_HEAD(&tmr->tmr_list);
  62
  63         return 0;
  64 }
  65 EXPORT_SYMBOL(core_tmr_alloc_req);
  66
  67 void core_tmr_release_req(
  68         struct se_tmr_req *tmr)
  69 {
  70         struct se_device *dev = tmr->tmr_dev;
  71         unsigned long flags;
  72
  73         if (!dev) {
  74                 kfree(tmr);
  75                 return;
  76         }
  77
  78         spin_lock_irqsave(&dev->se_tmr_lock, flags);
  79         list_del(&tmr->tmr_list);
  80         spin_unlock_irqrestore(&dev->se_tmr_lock, flags);
  81
  82         kfree(tmr);
  83 }
  84
  85 static void core_tmr_handle_tas_abort(
  86         struct se_node_acl *tmr_nacl,
  87         struct se_cmd *cmd,
  88         int tas,
  89         int fe_count)
  90 {
  91         if (!fe_count) {
  92                 transport_cmd_finish_abort(cmd, 1);
  93                 return;
  94         }
  95         /*
  96          * TASK ABORTED status (TAS) bit support
  97         */
  98         if ((tmr_nacl &&
  99              (tmr_nacl == cmd->se_sess->se_node_acl)) || tas)
 100                 transport_send_task_abort(cmd);
 101
 102         transport_cmd_finish_abort(cmd, 0);
 103 }
 104
 105 static int target_check_cdb_and_preempt(struct list_head *list,
 106                 struct se_cmd *cmd)
 107 {
 108         struct t10_pr_registration *reg;
 109
 110         if (!list)
 111                 return 0;
 112         list_for_each_entry(reg, list, pr_reg_abort_list) {
 113                 if (reg->pr_res_key == cmd->pr_res_key)
 114                         return 0;
 115         }
 116
 117         return 1;
 118 }
 119
 120 void core_tmr_abort_task(
 121         struct se_device *dev,
 122         struct se_tmr_req *tmr,
 123         struct se_session *se_sess)
 124 {
 125         struct se_cmd *se_cmd, *tmp_cmd;
 126         unsigned long flags;
 127         int ref_tag;
 128
 129         spin_lock_irqsave(&se_sess->sess_cmd_lock, flags);
 130         list_for_each_entry_safe(se_cmd, tmp_cmd,
 131                         &se_sess->sess_cmd_list, se_cmd_list) {
 132
 133                 if (dev != se_cmd->se_dev)
 134                         continue;
 135                 ref_tag = se_cmd->se_tfo->get_task_tag(se_cmd);
 136                 if (tmr->ref_task_tag != ref_tag)
 137                         continue;
 138
 139                 printk("ABORT_TASK: Found referenced %s task_tag: %u\n",
 140                         se_cmd->se_tfo->get_fabric_name(), ref_tag);
 141
 142                 spin_lock(&se_cmd->t_state_lock);
 143                 if (se_cmd->transport_state & CMD_T_COMPLETE) {
 144                         printk("ABORT_TASK: ref_tag: %u already complete, skipping\n", ref_tag);
 145                         spin_unlock(&se_cmd->t_state_lock);
 146                         spin_unlock_irqrestore(&se_sess->sess_cmd_lock, flags);
 147                         goto out;
 148                 }
 149                 se_cmd->transport_state |= CMD_T_ABORTED;
 150                 spin_unlock(&se_cmd->t_state_lock);
 151
 152                 list_del_init(&se_cmd->se_cmd_list);
 153                 kref_get(&se_cmd->cmd_kref);
 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                  * Now send SAM_STAT_TASK_ABORTED status for the referenced
 160                  * se_cmd descriptor..
 161                  */
 162                 transport_send_task_abort(se_cmd);
 163                 /*
 164                  * Also deal with possible extra acknowledge reference..
 165                  */
 166                 if (se_cmd->se_cmd_flags & SCF_ACK_KREF)
 167                         target_put_sess_cmd(se_sess, se_cmd);
 168
 169                 target_put_sess_cmd(se_sess, se_cmd);
 170
 171                 printk("ABORT_TASK: Sending TMR_FUNCTION_COMPLETE for"
 172                                 " ref_tag: %d\n", ref_tag);
 173                 tmr->response = TMR_FUNCTION_COMPLETE;
 174                 return;
 175         }
 176         spin_unlock_irqrestore(&se_sess->sess_cmd_lock, flags);
 177
 178 out:
 179         printk("ABORT_TASK: Sending TMR_TASK_DOES_NOT_EXIST for ref_tag: %d\n",
 180                         tmr->ref_task_tag);
 181         tmr->response = TMR_TASK_DOES_NOT_EXIST;
 182 }
 183
 184 static void core_tmr_drain_tmr_list(
 185         struct se_device *dev,
 186         struct se_tmr_req *tmr,
 187         struct list_head *preempt_and_abort_list)
 188 {
 189         LIST_HEAD(drain_tmr_list);
 190         struct se_tmr_req *tmr_p, *tmr_pp;
 191         struct se_cmd *cmd;
 192         unsigned long flags;
 193         /*
 194          * Release all pending and outgoing TMRs aside from the received
 195          * LUN_RESET tmr..
 196          */
 197         spin_lock_irqsave(&dev->se_tmr_lock, flags);
 198         list_for_each_entry_safe(tmr_p, tmr_pp, &dev->dev_tmr_list, tmr_list) {
 199                 /*
 200                  * Allow the received TMR to return with FUNCTION_COMPLETE.
 201                  */
 202                 if (tmr_p == tmr)
 203                         continue;
 204
 205                 cmd = tmr_p->task_cmd;
 206                 if (!cmd) {
 207                         pr_err("Unable to locate struct se_cmd for TMR\n");
 208                         continue;
 209                 }
 210                 /*
 211                  * If this function was called with a valid pr_res_key
 212                  * parameter (eg: for PROUT PREEMPT_AND_ABORT service action
 213                  * skip non regisration key matching TMRs.
 214                  */
 215                 if (target_check_cdb_and_preempt(preempt_and_abort_list, cmd))
 216                         continue;
 217
 218                 spin_lock(&cmd->t_state_lock);
 219                 if (!(cmd->transport_state & CMD_T_ACTIVE)) {
 220                         spin_unlock(&cmd->t_state_lock);
 221                         continue;
 222                 }
 223                 if (cmd->t_state == TRANSPORT_ISTATE_PROCESSING) {
 224                         spin_unlock(&cmd->t_state_lock);
 225                         continue;
 226                 }
 227                 spin_unlock(&cmd->t_state_lock);
 228
 229                 list_move_tail(&tmr_p->tmr_list, &drain_tmr_list);
 230         }
 231         spin_unlock_irqrestore(&dev->se_tmr_lock, flags);
 232
 233         list_for_each_entry_safe(tmr_p, tmr_pp, &drain_tmr_list, tmr_list) {
 234                 list_del_init(&tmr_p->tmr_list);
 235                 cmd = tmr_p->task_cmd;
 236
 237                 pr_debug("LUN_RESET: %s releasing TMR %p Function: 0x%02x,"
 238                         " Response: 0x%02x, t_state: %d\n",
 239                         (preempt_and_abort_list) ? "Preempt" : "", tmr_p,
 240                         tmr_p->function, tmr_p->response, cmd->t_state);
 241
 242                 transport_cmd_finish_abort(cmd, 1);
 243         }
 244 }
 245
 246 static void core_tmr_drain_state_list(
 247         struct se_device *dev,
 248         struct se_cmd *prout_cmd,
 249         struct se_node_acl *tmr_nacl,
 250         int tas,
 251         struct list_head *preempt_and_abort_list)
 252 {
 253         LIST_HEAD(drain_task_list);
 254         struct se_cmd *cmd, *next;
 255         unsigned long flags;
 256         int fe_count;
 257
 258         /*
 259          * Complete outstanding commands with TASK_ABORTED SAM status.
 260          *
 261          * This is following sam4r17, section 5.6 Aborting commands, Table 38
 262          * for TMR LUN_RESET:
 263          *
 264          * a) "Yes" indicates that each command that is aborted on an I_T nexus
 265          * other than the one that caused the SCSI device condition is
 266          * completed with TASK ABORTED status, if the TAS bit is set to one in
 267          * the Control mode page (see SPC-4). "No" indicates that no status is
 268          * returned for aborted commands.
 269          *
 270          * d) If the logical unit reset is caused by a particular I_T nexus
 271          * (e.g., by a LOGICAL UNIT RESET task management function), then "yes"
 272          * (TASK_ABORTED status) applies.
 273          *
 274          * Otherwise (e.g., if triggered by a hard reset), "no"
 275          * (no TASK_ABORTED SAM status) applies.
 276          *
 277          * Note that this seems to be independent of TAS (Task Aborted Status)
 278          * in the Control Mode Page.
 279          */
 280         spin_lock_irqsave(&dev->execute_task_lock, flags);
 281         list_for_each_entry_safe(cmd, next, &dev->state_list, state_list) {
 282                 /*
 283                  * For PREEMPT_AND_ABORT usage, only process commands
 284                  * with a matching reservation key.
 285                  */
 286                 if (target_check_cdb_and_preempt(preempt_and_abort_list, cmd))
 287                         continue;
 288
 289                 /*
 290                  * Not aborting PROUT PREEMPT_AND_ABORT CDB..
 291                  */
 292                 if (prout_cmd == cmd)
 293                         continue;
 294
 295                 list_move_tail(&cmd->state_list, &drain_task_list);
 296                 cmd->state_active = false;
 297         }
 298         spin_unlock_irqrestore(&dev->execute_task_lock, flags);
 299
 300         while (!list_empty(&drain_task_list)) {
 301                 cmd = list_entry(drain_task_list.next, struct se_cmd, state_list);
 302                 list_del(&cmd->state_list);
 303
 304                 pr_debug("LUN_RESET: %s cmd: %p"
 305                         " ITT/CmdSN: 0x%08x/0x%08x, i_state: %d, t_state: %d"
 306                         "cdb: 0x%02x\n",
 307                         (preempt_and_abort_list) ? "Preempt" : "", cmd,
 308                         cmd->se_tfo->get_task_tag(cmd), 0,
 309                         cmd->se_tfo->get_cmd_state(cmd), cmd->t_state,
 310                         cmd->t_task_cdb[0]);
 311                 pr_debug("LUN_RESET: ITT[0x%08x] - pr_res_key: 0x%016Lx"
 312                         " -- CMD_T_ACTIVE: %d"
 313                         " CMD_T_STOP: %d CMD_T_SENT: %d\n",
 314                         cmd->se_tfo->get_task_tag(cmd), cmd->pr_res_key,
 315                         (cmd->transport_state & CMD_T_ACTIVE) != 0,
 316                         (cmd->transport_state & CMD_T_STOP) != 0,
 317                         (cmd->transport_state & CMD_T_SENT) != 0);
 318
 319                 /*
 320                  * If the command may be queued onto a workqueue cancel it now.
 321                  *
 322                  * This is equivalent to removal from the execute queue in the
 323                  * loop above, but we do it down here given that
 324                  * cancel_work_sync may block.
 325                  */
 326                 if (cmd->t_state == TRANSPORT_COMPLETE)
 327                         cancel_work_sync(&cmd->work);
 328
 329                 spin_lock_irqsave(&cmd->t_state_lock, flags);
 330                 target_stop_cmd(cmd, &flags);
 331
 332                 fe_count = atomic_read(&cmd->t_fe_count);
 333
 334                 cmd->transport_state |= CMD_T_ABORTED;
 335                 spin_unlock_irqrestore(&cmd->t_state_lock, flags);
 336
 337                 core_tmr_handle_tas_abort(tmr_nacl, cmd, tas, fe_count);
 338         }
 339 }
 340
 341 int core_tmr_lun_reset(
 342         struct se_device *dev,
 343         struct se_tmr_req *tmr,
 344         struct list_head *preempt_and_abort_list,
 345         struct se_cmd *prout_cmd)
 346 {
 347         struct se_node_acl *tmr_nacl = NULL;
 348         struct se_portal_group *tmr_tpg = NULL;
 349         int tas;
 350         /*
 351          * TASK_ABORTED status bit, this is configurable via ConfigFS
 352          * struct se_device attributes.  spc4r17 section 7.4.6 Control mode page
 353          *
 354          * A task aborted status (TAS) bit set to zero specifies that aborted
 355          * tasks shall be terminated by the device server without any response
 356          * to the application client. A TAS bit set to one specifies that tasks
 357          * aborted by the actions of an I_T nexus other than the I_T nexus on
 358          * which the command was received shall be completed with TASK ABORTED
 359          * status (see SAM-4).
 360          */
 361         tas = dev->dev_attrib.emulate_tas;
 362         /*
 363          * Determine if this se_tmr is coming from a $FABRIC_MOD
 364          * or struct se_device passthrough..
 365          */
 366         if (tmr && tmr->task_cmd && tmr->task_cmd->se_sess) {
 367                 tmr_nacl = tmr->task_cmd->se_sess->se_node_acl;
 368                 tmr_tpg = tmr->task_cmd->se_sess->se_tpg;
 369                 if (tmr_nacl && tmr_tpg) {
 370                         pr_debug("LUN_RESET: TMR caller fabric: %s"
 371                                 " initiator port %s\n",
 372                                 tmr_tpg->se_tpg_tfo->get_fabric_name(),
 373                                 tmr_nacl->initiatorname);
 374                 }
 375         }
 376         pr_debug("LUN_RESET: %s starting for [%s], tas: %d\n",
 377                 (preempt_and_abort_list) ? "Preempt" : "TMR",
 378                 dev->transport->name, tas);
 379
 380         core_tmr_drain_tmr_list(dev, tmr, preempt_and_abort_list);
 381         core_tmr_drain_state_list(dev, prout_cmd, tmr_nacl, tas,
 382                                 preempt_and_abort_list);
 383
 384         /*
 385          * Clear any legacy SPC-2 reservation when called during
 386          * LOGICAL UNIT RESET
 387          */
 388         if (!preempt_and_abort_list &&
 389              (dev->dev_reservation_flags & DRF_SPC2_RESERVATIONS)) {
 390                 spin_lock(&dev->dev_reservation_lock);
 391                 dev->dev_reserved_node_acl = NULL;
 392                 dev->dev_reservation_flags &= ~DRF_SPC2_RESERVATIONS;
 393                 spin_unlock(&dev->dev_reservation_lock);
 394                 pr_debug("LUN_RESET: SCSI-2 Released reservation\n");
 395         }
 396
 397         spin_lock_irq(&dev->stats_lock);
 398         dev->num_resets++;
 399         spin_unlock_irq(&dev->stats_lock);
 400
 401         pr_debug("LUN_RESET: %s for [%s] Complete\n",
 402                         (preempt_and_abort_list) ? "Preempt" : "TMR",
 403                         dev->transport->name);
 404         return 0;
 405 }
 406