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(struct se_tmr_req *tmr)
  68 {
  69         struct se_device *dev = tmr->tmr_dev;
  70         unsigned long flags;
  71
  72         if (dev) {
  73                 spin_lock_irqsave(&dev->se_tmr_lock, flags);
  74                 list_del(&tmr->tmr_list);
  75                 spin_unlock_irqrestore(&dev->se_tmr_lock, flags);
  76         }
  77
  78         kfree(tmr);
  79 }
  80
  81 static void core_tmr_handle_tas_abort(
  82         struct se_node_acl *tmr_nacl,
  83         struct se_cmd *cmd,
  84         int tas)
  85 {
  86         bool remove = true;
  87         /*
  88          * TASK ABORTED status (TAS) bit support
  89          */
  90         if ((tmr_nacl && (tmr_nacl != cmd->se_sess->se_node_acl)) && tas) {
  91                 remove = false;
  92                 transport_send_task_abort(cmd);
  93         }
  94
  95         transport_cmd_finish_abort(cmd, remove);
  96 }
  97
  98 static int target_check_cdb_and_preempt(struct list_head *list,
  99                 struct se_cmd *cmd)
 100 {
 101         struct t10_pr_registration *reg;
 102
 103         if (!list)
 104                 return 0;
 105         list_for_each_entry(reg, list, pr_reg_abort_list) {
 106                 if (reg->pr_res_key == cmd->pr_res_key)
 107                         return 0;
 108         }
 109
 110         return 1;
 111 }
 112
 113 void core_tmr_abort_task(
 114         struct se_device *dev,
 115         struct se_tmr_req *tmr,
 116         struct se_session *se_sess)
 117 {
 118         struct se_cmd *se_cmd;
 119         unsigned long flags;
 120         int ref_tag;
 121
 122         spin_lock_irqsave(&se_sess->sess_cmd_lock, flags);
 123         list_for_each_entry(se_cmd, &se_sess->sess_cmd_list, se_cmd_list) {
 124
 125                 if (dev != se_cmd->se_dev)
 126                         continue;
 127
 128                 /* skip se_cmd associated with tmr */
 129                 if (tmr->task_cmd == se_cmd)
 130                         continue;
 131
 132                 ref_tag = se_cmd->se_tfo->get_task_tag(se_cmd);
 133                 if (tmr->ref_task_tag != ref_tag)
 134                         continue;
 135
 136                 printk("ABORT_TASK: Found referenced %s task_tag: %u\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: %u already complete, skipping\n", ref_tag);
 142                         spin_unlock(&se_cmd->t_state_lock);
 143                         spin_unlock_irqrestore(&se_sess->sess_cmd_lock, flags);
 144                         goto out;
 145                 }
 146                 se_cmd->transport_state |= CMD_T_ABORTED;
 147                 spin_unlock(&se_cmd->t_state_lock);
 148
 149                 list_del_init(&se_cmd->se_cmd_list);
 150                 kref_get(&se_cmd->cmd_kref);
 151                 spin_unlock_irqrestore(&se_sess->sess_cmd_lock, flags);
 152
 153                 cancel_work_sync(&se_cmd->work);
 154                 transport_wait_for_tasks(se_cmd);
 155
 156                 target_put_sess_cmd(se_sess, se_cmd);
 157                 transport_cmd_finish_abort(se_cmd, true);
 158
 159                 printk("ABORT_TASK: Sending TMR_FUNCTION_COMPLETE for"
 160                                 " ref_tag: %d\n", ref_tag);
 161                 tmr->response = TMR_FUNCTION_COMPLETE;
 162                 return;
 163         }
 164         spin_unlock_irqrestore(&se_sess->sess_cmd_lock, flags);
 165
 166 out:
 167         printk("ABORT_TASK: Sending TMR_TASK_DOES_NOT_EXIST for ref_tag: %d\n",
 168                         tmr->ref_task_tag);
 169         tmr->response = TMR_TASK_DOES_NOT_EXIST;
 170 }
 171
 172 static void core_tmr_drain_tmr_list(
 173         struct se_device *dev,
 174         struct se_tmr_req *tmr,
 175         struct list_head *preempt_and_abort_list)
 176 {
 177         LIST_HEAD(drain_tmr_list);
 178         struct se_tmr_req *tmr_p, *tmr_pp;
 179         struct se_cmd *cmd;
 180         unsigned long flags;
 181         /*
 182          * Release all pending and outgoing TMRs aside from the received
 183          * LUN_RESET tmr..
 184          */
 185         spin_lock_irqsave(&dev->se_tmr_lock, flags);
 186         list_for_each_entry_safe(tmr_p, tmr_pp, &dev->dev_tmr_list, tmr_list) {
 187                 /*
 188                  * Allow the received TMR to return with FUNCTION_COMPLETE.
 189                  */
 190                 if (tmr_p == tmr)
 191                         continue;
 192
 193                 cmd = tmr_p->task_cmd;
 194                 if (!cmd) {
 195                         pr_err("Unable to locate struct se_cmd for TMR\n");
 196                         continue;
 197                 }
 198                 /*
 199                  * If this function was called with a valid pr_res_key
 200                  * parameter (eg: for PROUT PREEMPT_AND_ABORT service action
 201                  * skip non regisration key matching TMRs.
 202                  */
 203                 if (target_check_cdb_and_preempt(preempt_and_abort_list, cmd))
 204                         continue;
 205
 206                 spin_lock(&cmd->t_state_lock);
 207                 if (!(cmd->transport_state & CMD_T_ACTIVE)) {
 208                         spin_unlock(&cmd->t_state_lock);
 209                         continue;
 210                 }
 211                 if (cmd->t_state == TRANSPORT_ISTATE_PROCESSING) {
 212                         spin_unlock(&cmd->t_state_lock);
 213                         continue;
 214                 }
 215                 spin_unlock(&cmd->t_state_lock);
 216
 217                 list_move_tail(&tmr_p->tmr_list, &drain_tmr_list);
 218         }
 219         spin_unlock_irqrestore(&dev->se_tmr_lock, flags);
 220
 221         list_for_each_entry_safe(tmr_p, tmr_pp, &drain_tmr_list, tmr_list) {
 222                 list_del_init(&tmr_p->tmr_list);
 223                 cmd = tmr_p->task_cmd;
 224
 225                 pr_debug("LUN_RESET: %s releasing TMR %p Function: 0x%02x,"
 226                         " Response: 0x%02x, t_state: %d\n",
 227                         (preempt_and_abort_list) ? "Preempt" : "", tmr_p,
 228                         tmr_p->function, tmr_p->response, cmd->t_state);
 229
 230                 transport_cmd_finish_abort(cmd, 1);
 231         }
 232 }
 233
 234 static void core_tmr_drain_state_list(
 235         struct se_device *dev,
 236         struct se_cmd *prout_cmd,
 237         struct se_node_acl *tmr_nacl,
 238         int tas,
 239         struct list_head *preempt_and_abort_list)
 240 {
 241         LIST_HEAD(drain_task_list);
 242         struct se_cmd *cmd, *next;
 243         unsigned long flags;
 244
 245         /*
 246          * Complete outstanding commands with TASK_ABORTED SAM status.
 247          *
 248          * This is following sam4r17, section 5.6 Aborting commands, Table 38
 249          * for TMR LUN_RESET:
 250          *
 251          * a) "Yes" indicates that each command that is aborted on an I_T nexus
 252          * other than the one that caused the SCSI device condition is
 253          * completed with TASK ABORTED status, if the TAS bit is set to one in
 254          * the Control mode page (see SPC-4). "No" indicates that no status is
 255          * returned for aborted commands.
 256          *
 257          * d) If the logical unit reset is caused by a particular I_T nexus
 258          * (e.g., by a LOGICAL UNIT RESET task management function), then "yes"
 259          * (TASK_ABORTED status) applies.
 260          *
 261          * Otherwise (e.g., if triggered by a hard reset), "no"
 262          * (no TASK_ABORTED SAM status) applies.
 263          *
 264          * Note that this seems to be independent of TAS (Task Aborted Status)
 265          * in the Control Mode Page.
 266          */
 267         spin_lock_irqsave(&dev->execute_task_lock, flags);
 268         list_for_each_entry_safe(cmd, next, &dev->state_list, state_list) {
 269                 /*
 270                  * For PREEMPT_AND_ABORT usage, only process commands
 271                  * with a matching reservation key.
 272                  */
 273                 if (target_check_cdb_and_preempt(preempt_and_abort_list, cmd))
 274                         continue;
 275
 276                 /*
 277                  * Not aborting PROUT PREEMPT_AND_ABORT CDB..
 278                  */
 279                 if (prout_cmd == cmd)
 280                         continue;
 281
 282                 list_move_tail(&cmd->state_list, &drain_task_list);
 283                 cmd->state_active = false;
 284         }
 285         spin_unlock_irqrestore(&dev->execute_task_lock, flags);
 286
 287         while (!list_empty(&drain_task_list)) {
 288                 cmd = list_entry(drain_task_list.next, struct se_cmd, state_list);
 289                 list_del(&cmd->state_list);
 290
 291                 pr_debug("LUN_RESET: %s cmd: %p"
 292                         " ITT/CmdSN: 0x%08x/0x%08x, i_state: %d, t_state: %d"
 293                         "cdb: 0x%02x\n",
 294                         (preempt_and_abort_list) ? "Preempt" : "", cmd,
 295                         cmd->se_tfo->get_task_tag(cmd), 0,
 296                         cmd->se_tfo->get_cmd_state(cmd), cmd->t_state,
 297                         cmd->t_task_cdb[0]);
 298                 pr_debug("LUN_RESET: ITT[0x%08x] - pr_res_key: 0x%016Lx"
 299                         " -- CMD_T_ACTIVE: %d"
 300                         " CMD_T_STOP: %d CMD_T_SENT: %d\n",
 301                         cmd->se_tfo->get_task_tag(cmd), cmd->pr_res_key,
 302                         (cmd->transport_state & CMD_T_ACTIVE) != 0,
 303                         (cmd->transport_state & CMD_T_STOP) != 0,
 304                         (cmd->transport_state & CMD_T_SENT) != 0);
 305
 306                 /*
 307                  * If the command may be queued onto a workqueue cancel it now.
 308                  *
 309                  * This is equivalent to removal from the execute queue in the
 310                  * loop above, but we do it down here given that
 311                  * cancel_work_sync may block.
 312                  */
 313                 if (cmd->t_state == TRANSPORT_COMPLETE)
 314                         cancel_work_sync(&cmd->work);
 315
 316                 spin_lock_irqsave(&cmd->t_state_lock, flags);
 317                 target_stop_cmd(cmd, &flags);
 318
 319                 cmd->transport_state |= CMD_T_ABORTED;
 320                 spin_unlock_irqrestore(&cmd->t_state_lock, flags);
 321
 322                 core_tmr_handle_tas_abort(tmr_nacl, cmd, tas);
 323         }
 324 }
 325
 326 int core_tmr_lun_reset(
 327         struct se_device *dev,
 328         struct se_tmr_req *tmr,
 329         struct list_head *preempt_and_abort_list,
 330         struct se_cmd *prout_cmd)
 331 {
 332         struct se_node_acl *tmr_nacl = NULL;
 333         struct se_portal_group *tmr_tpg = NULL;
 334         int tas;
 335         /*
 336          * TASK_ABORTED status bit, this is configurable via ConfigFS
 337          * struct se_device attributes.  spc4r17 section 7.4.6 Control mode page
 338          *
 339          * A task aborted status (TAS) bit set to zero specifies that aborted
 340          * tasks shall be terminated by the device server without any response
 341          * to the application client. A TAS bit set to one specifies that tasks
 342          * aborted by the actions of an I_T nexus other than the I_T nexus on
 343          * which the command was received shall be completed with TASK ABORTED
 344          * status (see SAM-4).
 345          */
 346         tas = dev->dev_attrib.emulate_tas;
 347         /*
 348          * Determine if this se_tmr is coming from a $FABRIC_MOD
 349          * or struct se_device passthrough..
 350          */
 351         if (tmr && tmr->task_cmd && tmr->task_cmd->se_sess) {
 352                 tmr_nacl = tmr->task_cmd->se_sess->se_node_acl;
 353                 tmr_tpg = tmr->task_cmd->se_sess->se_tpg;
 354                 if (tmr_nacl && tmr_tpg) {
 355                         pr_debug("LUN_RESET: TMR caller fabric: %s"
 356                                 " initiator port %s\n",
 357                                 tmr_tpg->se_tpg_tfo->get_fabric_name(),
 358                                 tmr_nacl->initiatorname);
 359                 }
 360         }
 361         pr_debug("LUN_RESET: %s starting for [%s], tas: %d\n",
 362                 (preempt_and_abort_list) ? "Preempt" : "TMR",
 363                 dev->transport->name, tas);
 364
 365         core_tmr_drain_tmr_list(dev, tmr, preempt_and_abort_list);
 366         core_tmr_drain_state_list(dev, prout_cmd, tmr_nacl, tas,
 367                                 preempt_and_abort_list);
 368
 369         /*
 370          * Clear any legacy SPC-2 reservation when called during
 371          * LOGICAL UNIT RESET
 372          */
 373         if (!preempt_and_abort_list &&
 374              (dev->dev_reservation_flags & DRF_SPC2_RESERVATIONS)) {
 375                 spin_lock(&dev->dev_reservation_lock);
 376                 dev->dev_reserved_node_acl = NULL;
 377                 dev->dev_reservation_flags &= ~DRF_SPC2_RESERVATIONS;
 378                 spin_unlock(&dev->dev_reservation_lock);
 379                 pr_debug("LUN_RESET: SCSI-2 Released reservation\n");
 380         }
 381
 382         atomic_long_inc(&dev->num_resets);
 383
 384         pr_debug("LUN_RESET: %s for [%s] Complete\n",
 385                         (preempt_and_abort_list) ? "Preempt" : "TMR",
 386                         dev->transport->name);
 387         return 0;
 388 }
 389