linux/drivers/target/target_core_tmr.c
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   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
  42int 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}
  65EXPORT_SYMBOL(core_tmr_alloc_req);
  66
  67void 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
  85static 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
 105static 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
 120void 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
 178out:
 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
 184static 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
 246static 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
 341int 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
 407
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