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 #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 {
  90         bool remove = true;
  91         /*
  92          * TASK ABORTED status (TAS) bit support
  93         */
  94         if ((tmr_nacl &&
  95              (tmr_nacl != cmd->se_sess->se_node_acl)) && tas) {
  96                 remove = false;
  97                 transport_send_task_abort(cmd);
  98         }
  99
 100         transport_cmd_finish_abort(cmd, remove);
 101 }
 102
 103 static int target_check_cdb_and_preempt(struct list_head *list,
 104                 struct se_cmd *cmd)
 105 {
 106         struct t10_pr_registration *reg;
 107
 108         if (!list)
 109                 return 0;
 110         list_for_each_entry(reg, list, pr_reg_abort_list) {
 111                 if (reg->pr_res_key == cmd->pr_res_key)
 112                         return 0;
 113         }
 114
 115         return 1;
 116 }
 117
 118 void core_tmr_abort_task(
 119         struct se_device *dev,
 120         struct se_tmr_req *tmr,
 121         struct se_session *se_sess)
 122 {
 123         struct se_cmd *se_cmd, *tmp_cmd;
 124         unsigned long flags;
 125         int ref_tag;
 126
 127         spin_lock_irqsave(&se_sess->sess_cmd_lock, flags);
 128         list_for_each_entry_safe(se_cmd, tmp_cmd,
 129                         &se_sess->sess_cmd_list, se_cmd_list) {
 130
 131                 if (dev != se_cmd->se_dev)
 132                         continue;
 133
 134                 /* skip se_cmd associated with tmr */
 135                 if (tmr->task_cmd == se_cmd)
 136                         continue;
 137
 138                 ref_tag = se_cmd->se_tfo->get_task_tag(se_cmd);
 139                 if (tmr->ref_task_tag != ref_tag)
 140                         continue;
 141
 142                 printk("ABORT_TASK: Found referenced %s task_tag: %u\n",
 143                         se_cmd->se_tfo->get_fabric_name(), ref_tag);
 144
 145                 spin_lock(&se_cmd->t_state_lock);
 146                 if (se_cmd->transport_state & CMD_T_COMPLETE) {
 147                         printk("ABORT_TASK: ref_tag: %u already complete, skipping\n", ref_tag);
 148                         spin_unlock(&se_cmd->t_state_lock);
 149                         spin_unlock_irqrestore(&se_sess->sess_cmd_lock, flags);
 150                         goto out;
 151                 }
 152                 se_cmd->transport_state |= CMD_T_ABORTED;
 153                 spin_unlock(&se_cmd->t_state_lock);
 154
 155                 list_del_init(&se_cmd->se_cmd_list);
 156                 kref_get(&se_cmd->cmd_kref);
 157                 spin_unlock_irqrestore(&se_sess->sess_cmd_lock, flags);
 158
 159                 cancel_work_sync(&se_cmd->work);
 160                 transport_wait_for_tasks(se_cmd);
 161
 162                 target_put_sess_cmd(se_sess, se_cmd);
 163                 transport_cmd_finish_abort(se_cmd, true);
 164
 165                 printk("ABORT_TASK: Sending TMR_FUNCTION_COMPLETE for"
 166                                 " ref_tag: %d\n", ref_tag);
 167                 tmr->response = TMR_FUNCTION_COMPLETE;
 168                 return;
 169         }
 170         spin_unlock_irqrestore(&se_sess->sess_cmd_lock, flags);
 171
 172 out:
 173         printk("ABORT_TASK: Sending TMR_TASK_DOES_NOT_EXIST for ref_tag: %d\n",
 174                         tmr->ref_task_tag);
 175         tmr->response = TMR_TASK_DOES_NOT_EXIST;
 176 }
 177
 178 static void core_tmr_drain_tmr_list(
 179         struct se_device *dev,
 180         struct se_tmr_req *tmr,
 181         struct list_head *preempt_and_abort_list)
 182 {
 183         LIST_HEAD(drain_tmr_list);
 184         struct se_tmr_req *tmr_p, *tmr_pp;
 185         struct se_cmd *cmd;
 186         unsigned long flags;
 187         /*
 188          * Release all pending and outgoing TMRs aside from the received
 189          * LUN_RESET tmr..
 190          */
 191         spin_lock_irqsave(&dev->se_tmr_lock, flags);
 192         list_for_each_entry_safe(tmr_p, tmr_pp, &dev->dev_tmr_list, tmr_list) {
 193                 /*
 194                  * Allow the received TMR to return with FUNCTION_COMPLETE.
 195                  */
 196                 if (tmr_p == tmr)
 197                         continue;
 198
 199                 cmd = tmr_p->task_cmd;
 200                 if (!cmd) {
 201                         pr_err("Unable to locate struct se_cmd for TMR\n");
 202                         continue;
 203                 }
 204                 /*
 205                  * If this function was called with a valid pr_res_key
 206                  * parameter (eg: for PROUT PREEMPT_AND_ABORT service action
 207                  * skip non regisration key matching TMRs.
 208                  */
 209                 if (target_check_cdb_and_preempt(preempt_and_abort_list, cmd))
 210                         continue;
 211
 212                 spin_lock(&cmd->t_state_lock);
 213                 if (!(cmd->transport_state & CMD_T_ACTIVE)) {
 214                         spin_unlock(&cmd->t_state_lock);
 215                         continue;
 216                 }
 217                 if (cmd->t_state == TRANSPORT_ISTATE_PROCESSING) {
 218                         spin_unlock(&cmd->t_state_lock);
 219                         continue;
 220                 }
 221                 spin_unlock(&cmd->t_state_lock);
 222
 223                 list_move_tail(&tmr_p->tmr_list, &drain_tmr_list);
 224         }
 225         spin_unlock_irqrestore(&dev->se_tmr_lock, flags);
 226
 227         list_for_each_entry_safe(tmr_p, tmr_pp, &drain_tmr_list, tmr_list) {
 228                 list_del_init(&tmr_p->tmr_list);
 229                 cmd = tmr_p->task_cmd;
 230
 231                 pr_debug("LUN_RESET: %s releasing TMR %p Function: 0x%02x,"
 232                         " Response: 0x%02x, t_state: %d\n",
 233                         (preempt_and_abort_list) ? "Preempt" : "", tmr_p,
 234                         tmr_p->function, tmr_p->response, cmd->t_state);
 235
 236                 transport_cmd_finish_abort(cmd, 1);
 237         }
 238 }
 239
 240 static void core_tmr_drain_state_list(
 241         struct se_device *dev,
 242         struct se_cmd *prout_cmd,
 243         struct se_node_acl *tmr_nacl,
 244         int tas,
 245         struct list_head *preempt_and_abort_list)
 246 {
 247         LIST_HEAD(drain_task_list);
 248         struct se_cmd *cmd, *next;
 249         unsigned long flags;
 250
 251         /*
 252          * Complete outstanding commands with TASK_ABORTED SAM status.
 253          *
 254          * This is following sam4r17, section 5.6 Aborting commands, Table 38
 255          * for TMR LUN_RESET:
 256          *
 257          * a) "Yes" indicates that each command that is aborted on an I_T nexus
 258          * other than the one that caused the SCSI device condition is
 259          * completed with TASK ABORTED status, if the TAS bit is set to one in
 260          * the Control mode page (see SPC-4). "No" indicates that no status is
 261          * returned for aborted commands.
 262          *
 263          * d) If the logical unit reset is caused by a particular I_T nexus
 264          * (e.g., by a LOGICAL UNIT RESET task management function), then "yes"
 265          * (TASK_ABORTED status) applies.
 266          *
 267          * Otherwise (e.g., if triggered by a hard reset), "no"
 268          * (no TASK_ABORTED SAM status) applies.
 269          *
 270          * Note that this seems to be independent of TAS (Task Aborted Status)
 271          * in the Control Mode Page.
 272          */
 273         spin_lock_irqsave(&dev->execute_task_lock, flags);
 274         list_for_each_entry_safe(cmd, next, &dev->state_list, state_list) {
 275                 /*
 276                  * For PREEMPT_AND_ABORT usage, only process commands
 277                  * with a matching reservation key.
 278                  */
 279                 if (target_check_cdb_and_preempt(preempt_and_abort_list, cmd))
 280                         continue;
 281
 282                 /*
 283                  * Not aborting PROUT PREEMPT_AND_ABORT CDB..
 284                  */
 285                 if (prout_cmd == cmd)
 286                         continue;
 287
 288                 list_move_tail(&cmd->state_list, &drain_task_list);
 289                 cmd->state_active = false;
 290         }
 291         spin_unlock_irqrestore(&dev->execute_task_lock, flags);
 292
 293         while (!list_empty(&drain_task_list)) {
 294                 cmd = list_entry(drain_task_list.next, struct se_cmd, state_list);
 295                 list_del(&cmd->state_list);
 296
 297                 pr_debug("LUN_RESET: %s cmd: %p"
 298                         " ITT/CmdSN: 0x%08x/0x%08x, i_state: %d, t_state: %d"
 299                         "cdb: 0x%02x\n",
 300                         (preempt_and_abort_list) ? "Preempt" : "", cmd,
 301                         cmd->se_tfo->get_task_tag(cmd), 0,
 302                         cmd->se_tfo->get_cmd_state(cmd), cmd->t_state,
 303                         cmd->t_task_cdb[0]);
 304                 pr_debug("LUN_RESET: ITT[0x%08x] - pr_res_key: 0x%016Lx"
 305                         " -- CMD_T_ACTIVE: %d"
 306                         " CMD_T_STOP: %d CMD_T_SENT: %d\n",
 307                         cmd->se_tfo->get_task_tag(cmd), cmd->pr_res_key,
 308                         (cmd->transport_state & CMD_T_ACTIVE) != 0,
 309                         (cmd->transport_state & CMD_T_STOP) != 0,
 310                         (cmd->transport_state & CMD_T_SENT) != 0);
 311
 312                 /*
 313                  * If the command may be queued onto a workqueue cancel it now.
 314                  *
 315                  * This is equivalent to removal from the execute queue in the
 316                  * loop above, but we do it down here given that
 317                  * cancel_work_sync may block.
 318                  */
 319                 if (cmd->t_state == TRANSPORT_COMPLETE)
 320                         cancel_work_sync(&cmd->work);
 321
 322                 spin_lock_irqsave(&cmd->t_state_lock, flags);
 323                 target_stop_cmd(cmd, &flags);
 324
 325                 cmd->transport_state |= CMD_T_ABORTED;
 326                 spin_unlock_irqrestore(&cmd->t_state_lock, flags);
 327
 328                 core_tmr_handle_tas_abort(tmr_nacl, cmd, tas);
 329         }
 330 }
 331
 332 int core_tmr_lun_reset(
 333         struct se_device *dev,
 334         struct se_tmr_req *tmr,
 335         struct list_head *preempt_and_abort_list,
 336         struct se_cmd *prout_cmd)
 337 {
 338         struct se_node_acl *tmr_nacl = NULL;
 339         struct se_portal_group *tmr_tpg = NULL;
 340         int tas;
 341         /*
 342          * TASK_ABORTED status bit, this is configurable via ConfigFS
 343          * struct se_device attributes.  spc4r17 section 7.4.6 Control mode page
 344          *
 345          * A task aborted status (TAS) bit set to zero specifies that aborted
 346          * tasks shall be terminated by the device server without any response
 347          * to the application client. A TAS bit set to one specifies that tasks
 348          * aborted by the actions of an I_T nexus other than the I_T nexus on
 349          * which the command was received shall be completed with TASK ABORTED
 350          * status (see SAM-4).
 351          */
 352         tas = dev->dev_attrib.emulate_tas;
 353         /*
 354          * Determine if this se_tmr is coming from a $FABRIC_MOD
 355          * or struct se_device passthrough..
 356          */
 357         if (tmr && tmr->task_cmd && tmr->task_cmd->se_sess) {
 358                 tmr_nacl = tmr->task_cmd->se_sess->se_node_acl;
 359                 tmr_tpg = tmr->task_cmd->se_sess->se_tpg;
 360                 if (tmr_nacl && tmr_tpg) {
 361                         pr_debug("LUN_RESET: TMR caller fabric: %s"
 362                                 " initiator port %s\n",
 363                                 tmr_tpg->se_tpg_tfo->get_fabric_name(),
 364                                 tmr_nacl->initiatorname);
 365                 }
 366         }
 367         pr_debug("LUN_RESET: %s starting for [%s], tas: %d\n",
 368                 (preempt_and_abort_list) ? "Preempt" : "TMR",
 369                 dev->transport->name, tas);
 370
 371         core_tmr_drain_tmr_list(dev, tmr, preempt_and_abort_list);
 372         core_tmr_drain_state_list(dev, prout_cmd, tmr_nacl, tas,
 373                                 preempt_and_abort_list);
 374
 375         /*
 376          * Clear any legacy SPC-2 reservation when called during
 377          * LOGICAL UNIT RESET
 378          */
 379         if (!preempt_and_abort_list &&
 380              (dev->dev_reservation_flags & DRF_SPC2_RESERVATIONS)) {
 381                 spin_lock(&dev->dev_reservation_lock);
 382                 dev->dev_reserved_node_acl = NULL;
 383                 dev->dev_reservation_flags &= ~DRF_SPC2_RESERVATIONS;
 384                 spin_unlock(&dev->dev_reservation_lock);
 385                 pr_debug("LUN_RESET: SCSI-2 Released reservation\n");
 386         }
 387
 388         atomic_long_inc(&dev->num_resets);
 389
 390         pr_debug("LUN_RESET: %s for [%s] Complete\n",
 391                         (preempt_and_abort_list) ? "Preempt" : "TMR",
 392                         dev->transport->name);
 393         return 0;
 394 }
 395