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 * Copyright (c) 2009,2010 Rising Tide Systems
   7 * Copyright (c) 2009,2010 Linux-iSCSI.org
   8 *
   9 * Nicholas A. Bellinger <nab@kernel.org>
  10 *
  11 * This program is free software; you can redistribute it and/or modify
  12 * it under the terms of the GNU General Public License as published by
  13 * the Free Software Foundation; either version 2 of the License, or
  14 * (at your option) any later version.
  15 *
  16 * This program is distributed in the hope that it will be useful,
  17 * but WITHOUT ANY WARRANTY; without even the implied warranty of
  18 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  19 * GNU General Public License for more details.
  20 *
  21 * You should have received a copy of the GNU General Public License
  22 * along with this program; if not, write to the Free Software
  23 * Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
  24 *
  25 ******************************************************************************/
  26
  27#include <linux/slab.h>
  28#include <linux/spinlock.h>
  29#include <linux/list.h>
  30#include <linux/export.h>
  31#include <scsi/scsi.h>
  32#include <scsi/scsi_cmnd.h>
  33
  34#include <target/target_core_base.h>
  35#include <target/target_core_backend.h>
  36#include <target/target_core_fabric.h>
  37#include <target/target_core_configfs.h>
  38
  39#include "target_core_internal.h"
  40#include "target_core_alua.h"
  41#include "target_core_pr.h"
  42
  43int core_tmr_alloc_req(
  44        struct se_cmd *se_cmd,
  45        void *fabric_tmr_ptr,
  46        u8 function,
  47        gfp_t gfp_flags)
  48{
  49        struct se_tmr_req *tmr;
  50
  51        tmr = kzalloc(sizeof(struct se_tmr_req), gfp_flags);
  52        if (!tmr) {
  53                pr_err("Unable to allocate struct se_tmr_req\n");
  54                return -ENOMEM;
  55        }
  56
  57        se_cmd->se_cmd_flags |= SCF_SCSI_TMR_CDB;
  58        se_cmd->se_tmr_req = tmr;
  59        tmr->task_cmd = se_cmd;
  60        tmr->fabric_tmr_ptr = fabric_tmr_ptr;
  61        tmr->function = function;
  62        INIT_LIST_HEAD(&tmr->tmr_list);
  63
  64        return 0;
  65}
  66EXPORT_SYMBOL(core_tmr_alloc_req);
  67
  68void core_tmr_release_req(
  69        struct se_tmr_req *tmr)
  70{
  71        struct se_device *dev = tmr->tmr_dev;
  72        unsigned long flags;
  73
  74        if (!dev) {
  75                kfree(tmr);
  76                return;
  77        }
  78
  79        spin_lock_irqsave(&dev->se_tmr_lock, flags);
  80        list_del(&tmr->tmr_list);
  81        spin_unlock_irqrestore(&dev->se_tmr_lock, flags);
  82
  83        kfree(tmr);
  84}
  85
  86static void core_tmr_handle_tas_abort(
  87        struct se_node_acl *tmr_nacl,
  88        struct se_cmd *cmd,
  89        int tas,
  90        int fe_count)
  91{
  92        if (!fe_count) {
  93                transport_cmd_finish_abort(cmd, 1);
  94                return;
  95        }
  96        /*
  97         * TASK ABORTED status (TAS) bit support
  98        */
  99        if ((tmr_nacl &&
 100             (tmr_nacl == cmd->se_sess->se_node_acl)) || tas)
 101                transport_send_task_abort(cmd);
 102
 103        transport_cmd_finish_abort(cmd, 0);
 104}
 105
 106static int target_check_cdb_and_preempt(struct list_head *list,
 107                struct se_cmd *cmd)
 108{
 109        struct t10_pr_registration *reg;
 110
 111        if (!list)
 112                return 0;
 113        list_for_each_entry(reg, list, pr_reg_abort_list) {
 114                if (reg->pr_res_key == cmd->pr_res_key)
 115                        return 0;
 116        }
 117
 118        return 1;
 119}
 120
 121void core_tmr_abort_task(
 122        struct se_device *dev,
 123        struct se_tmr_req *tmr,
 124        struct se_session *se_sess)
 125{
 126        struct se_cmd *se_cmd, *tmp_cmd;
 127        unsigned long flags;
 128        int ref_tag;
 129
 130        spin_lock_irqsave(&se_sess->sess_cmd_lock, flags);
 131        list_for_each_entry_safe(se_cmd, tmp_cmd,
 132                        &se_sess->sess_cmd_list, se_cmd_list) {
 133
 134                if (dev != se_cmd->se_dev)
 135                        continue;
 136                ref_tag = se_cmd->se_tfo->get_task_tag(se_cmd);
 137                if (tmr->ref_task_tag != ref_tag)
 138                        continue;
 139
 140                printk("ABORT_TASK: Found referenced %s task_tag: %u\n",
 141                        se_cmd->se_tfo->get_fabric_name(), ref_tag);
 142
 143                spin_lock_irq(&se_cmd->t_state_lock);
 144                if (se_cmd->transport_state & CMD_T_COMPLETE) {
 145                        printk("ABORT_TASK: ref_tag: %u already complete, skipping\n", ref_tag);
 146                        spin_unlock_irq(&se_cmd->t_state_lock);
 147                        spin_unlock_irqrestore(&se_sess->sess_cmd_lock, flags);
 148                        goto out;
 149                }
 150                se_cmd->transport_state |= CMD_T_ABORTED;
 151                spin_unlock_irq(&se_cmd->t_state_lock);
 152
 153                list_del_init(&se_cmd->se_cmd_list);
 154                kref_get(&se_cmd->cmd_kref);
 155                spin_unlock_irqrestore(&se_sess->sess_cmd_lock, flags);
 156
 157                cancel_work_sync(&se_cmd->work);
 158                transport_wait_for_tasks(se_cmd);
 159                /*
 160                 * Now send SAM_STAT_TASK_ABORTED status for the referenced
 161                 * se_cmd descriptor..
 162                 */
 163                transport_send_task_abort(se_cmd);
 164                /*
 165                 * Also deal with possible extra acknowledge reference..
 166                 */
 167                if (se_cmd->se_cmd_flags & SCF_ACK_KREF)
 168                        target_put_sess_cmd(se_sess, se_cmd);
 169
 170                target_put_sess_cmd(se_sess, se_cmd);
 171
 172                printk("ABORT_TASK: Sending TMR_FUNCTION_COMPLETE for"
 173                                " ref_tag: %d\n", ref_tag);
 174                tmr->response = TMR_FUNCTION_COMPLETE;
 175                return;
 176        }
 177        spin_unlock_irqrestore(&se_sess->sess_cmd_lock, flags);
 178
 179out:
 180        printk("ABORT_TASK: Sending TMR_TASK_DOES_NOT_EXIST for ref_tag: %d\n",
 181                        tmr->ref_task_tag);
 182        tmr->response = TMR_TASK_DOES_NOT_EXIST;
 183}
 184
 185static void core_tmr_drain_tmr_list(
 186        struct se_device *dev,
 187        struct se_tmr_req *tmr,
 188        struct list_head *preempt_and_abort_list)
 189{
 190        LIST_HEAD(drain_tmr_list);
 191        struct se_tmr_req *tmr_p, *tmr_pp;
 192        struct se_cmd *cmd;
 193        unsigned long flags;
 194        /*
 195         * Release all pending and outgoing TMRs aside from the received
 196         * LUN_RESET tmr..
 197         */
 198        spin_lock_irqsave(&dev->se_tmr_lock, flags);
 199        list_for_each_entry_safe(tmr_p, tmr_pp, &dev->dev_tmr_list, tmr_list) {
 200                /*
 201                 * Allow the received TMR to return with FUNCTION_COMPLETE.
 202                 */
 203                if (tmr_p == tmr)
 204                        continue;
 205
 206                cmd = tmr_p->task_cmd;
 207                if (!cmd) {
 208                        pr_err("Unable to locate struct se_cmd for TMR\n");
 209                        continue;
 210                }
 211                /*
 212                 * If this function was called with a valid pr_res_key
 213                 * parameter (eg: for PROUT PREEMPT_AND_ABORT service action
 214                 * skip non regisration key matching TMRs.
 215                 */
 216                if (target_check_cdb_and_preempt(preempt_and_abort_list, cmd))
 217                        continue;
 218
 219                spin_lock(&cmd->t_state_lock);
 220                if (!(cmd->transport_state & CMD_T_ACTIVE)) {
 221                        spin_unlock(&cmd->t_state_lock);
 222                        continue;
 223                }
 224                if (cmd->t_state == TRANSPORT_ISTATE_PROCESSING) {
 225                        spin_unlock(&cmd->t_state_lock);
 226                        continue;
 227                }
 228                spin_unlock(&cmd->t_state_lock);
 229
 230                list_move_tail(&tmr_p->tmr_list, &drain_tmr_list);
 231        }
 232        spin_unlock_irqrestore(&dev->se_tmr_lock, flags);
 233
 234        list_for_each_entry_safe(tmr_p, tmr_pp, &drain_tmr_list, tmr_list) {
 235                list_del_init(&tmr_p->tmr_list);
 236                cmd = tmr_p->task_cmd;
 237
 238                pr_debug("LUN_RESET: %s releasing TMR %p Function: 0x%02x,"
 239                        " Response: 0x%02x, t_state: %d\n",
 240                        (preempt_and_abort_list) ? "Preempt" : "", tmr_p,
 241                        tmr_p->function, tmr_p->response, cmd->t_state);
 242
 243                transport_cmd_finish_abort(cmd, 1);
 244        }
 245}
 246
 247static void core_tmr_drain_state_list(
 248        struct se_device *dev,
 249        struct se_cmd *prout_cmd,
 250        struct se_node_acl *tmr_nacl,
 251        int tas,
 252        struct list_head *preempt_and_abort_list)
 253{
 254        LIST_HEAD(drain_task_list);
 255        struct se_cmd *cmd, *next;
 256        unsigned long flags;
 257        int fe_count;
 258
 259        /*
 260         * Complete outstanding commands with TASK_ABORTED SAM status.
 261         *
 262         * This is following sam4r17, section 5.6 Aborting commands, Table 38
 263         * for TMR LUN_RESET:
 264         *
 265         * a) "Yes" indicates that each command that is aborted on an I_T nexus
 266         * other than the one that caused the SCSI device condition is
 267         * completed with TASK ABORTED status, if the TAS bit is set to one in
 268         * the Control mode page (see SPC-4). "No" indicates that no status is
 269         * returned for aborted commands.
 270         *
 271         * d) If the logical unit reset is caused by a particular I_T nexus
 272         * (e.g., by a LOGICAL UNIT RESET task management function), then "yes"
 273         * (TASK_ABORTED status) applies.
 274         *
 275         * Otherwise (e.g., if triggered by a hard reset), "no"
 276         * (no TASK_ABORTED SAM status) applies.
 277         *
 278         * Note that this seems to be independent of TAS (Task Aborted Status)
 279         * in the Control Mode Page.
 280         */
 281        spin_lock_irqsave(&dev->execute_task_lock, flags);
 282        list_for_each_entry_safe(cmd, next, &dev->state_list, state_list) {
 283                /*
 284                 * For PREEMPT_AND_ABORT usage, only process commands
 285                 * with a matching reservation key.
 286                 */
 287                if (target_check_cdb_and_preempt(preempt_and_abort_list, cmd))
 288                        continue;
 289
 290                /*
 291                 * Not aborting PROUT PREEMPT_AND_ABORT CDB..
 292                 */
 293                if (prout_cmd == cmd)
 294                        continue;
 295
 296                list_move_tail(&cmd->state_list, &drain_task_list);
 297                cmd->state_active = false;
 298        }
 299        spin_unlock_irqrestore(&dev->execute_task_lock, flags);
 300
 301        while (!list_empty(&drain_task_list)) {
 302                cmd = list_entry(drain_task_list.next, struct se_cmd, state_list);
 303                list_del(&cmd->state_list);
 304
 305                pr_debug("LUN_RESET: %s cmd: %p"
 306                        " ITT/CmdSN: 0x%08x/0x%08x, i_state: %d, t_state: %d"
 307                        "cdb: 0x%02x\n",
 308                        (preempt_and_abort_list) ? "Preempt" : "", cmd,
 309                        cmd->se_tfo->get_task_tag(cmd), 0,
 310                        cmd->se_tfo->get_cmd_state(cmd), cmd->t_state,
 311                        cmd->t_task_cdb[0]);
 312                pr_debug("LUN_RESET: ITT[0x%08x] - pr_res_key: 0x%016Lx"
 313                        " -- CMD_T_ACTIVE: %d"
 314                        " CMD_T_STOP: %d CMD_T_SENT: %d\n",
 315                        cmd->se_tfo->get_task_tag(cmd), cmd->pr_res_key,
 316                        (cmd->transport_state & CMD_T_ACTIVE) != 0,
 317                        (cmd->transport_state & CMD_T_STOP) != 0,
 318                        (cmd->transport_state & CMD_T_SENT) != 0);
 319
 320                /*
 321                 * If the command may be queued onto a workqueue cancel it now.
 322                 *
 323                 * This is equivalent to removal from the execute queue in the
 324                 * loop above, but we do it down here given that
 325                 * cancel_work_sync may block.
 326                 */
 327                if (cmd->t_state == TRANSPORT_COMPLETE)
 328                        cancel_work_sync(&cmd->work);
 329
 330                spin_lock_irqsave(&cmd->t_state_lock, flags);
 331                target_stop_cmd(cmd, &flags);
 332
 333                fe_count = atomic_read(&cmd->t_fe_count);
 334
 335                if (!(cmd->transport_state & CMD_T_ACTIVE)) {
 336                        pr_debug("LUN_RESET: got CMD_T_ACTIVE for"
 337                                " cdb: %p, t_fe_count: %d dev: %p\n", cmd,
 338                                fe_count, dev);
 339                        cmd->transport_state |= CMD_T_ABORTED;
 340                        spin_unlock_irqrestore(&cmd->t_state_lock, flags);
 341
 342                        core_tmr_handle_tas_abort(tmr_nacl, cmd, tas, fe_count);
 343                        continue;
 344                }
 345                pr_debug("LUN_RESET: Got !CMD_T_ACTIVE for cdb: %p,"
 346                        " t_fe_count: %d dev: %p\n", cmd, fe_count, dev);
 347                cmd->transport_state |= CMD_T_ABORTED;
 348                spin_unlock_irqrestore(&cmd->t_state_lock, flags);
 349
 350                core_tmr_handle_tas_abort(tmr_nacl, cmd, tas, fe_count);
 351        }
 352}
 353
 354int core_tmr_lun_reset(
 355        struct se_device *dev,
 356        struct se_tmr_req *tmr,
 357        struct list_head *preempt_and_abort_list,
 358        struct se_cmd *prout_cmd)
 359{
 360        struct se_node_acl *tmr_nacl = NULL;
 361        struct se_portal_group *tmr_tpg = NULL;
 362        int tas;
 363        /*
 364         * TASK_ABORTED status bit, this is configurable via ConfigFS
 365         * struct se_device attributes.  spc4r17 section 7.4.6 Control mode page
 366         *
 367         * A task aborted status (TAS) bit set to zero specifies that aborted
 368         * tasks shall be terminated by the device server without any response
 369         * to the application client. A TAS bit set to one specifies that tasks
 370         * aborted by the actions of an I_T nexus other than the I_T nexus on
 371         * which the command was received shall be completed with TASK ABORTED
 372         * status (see SAM-4).
 373         */
 374        tas = dev->se_sub_dev->se_dev_attrib.emulate_tas;
 375        /*
 376         * Determine if this se_tmr is coming from a $FABRIC_MOD
 377         * or struct se_device passthrough..
 378         */
 379        if (tmr && tmr->task_cmd && tmr->task_cmd->se_sess) {
 380                tmr_nacl = tmr->task_cmd->se_sess->se_node_acl;
 381                tmr_tpg = tmr->task_cmd->se_sess->se_tpg;
 382                if (tmr_nacl && tmr_tpg) {
 383                        pr_debug("LUN_RESET: TMR caller fabric: %s"
 384                                " initiator port %s\n",
 385                                tmr_tpg->se_tpg_tfo->get_fabric_name(),
 386                                tmr_nacl->initiatorname);
 387                }
 388        }
 389        pr_debug("LUN_RESET: %s starting for [%s], tas: %d\n",
 390                (preempt_and_abort_list) ? "Preempt" : "TMR",
 391                dev->transport->name, tas);
 392
 393        core_tmr_drain_tmr_list(dev, tmr, preempt_and_abort_list);
 394        core_tmr_drain_state_list(dev, prout_cmd, tmr_nacl, tas,
 395                                preempt_and_abort_list);
 396
 397        /*
 398         * Clear any legacy SPC-2 reservation when called during
 399         * LOGICAL UNIT RESET
 400         */
 401        if (!preempt_and_abort_list &&
 402             (dev->dev_flags & DF_SPC2_RESERVATIONS)) {
 403                spin_lock(&dev->dev_reservation_lock);
 404                dev->dev_reserved_node_acl = NULL;
 405                dev->dev_flags &= ~DF_SPC2_RESERVATIONS;
 406                spin_unlock(&dev->dev_reservation_lock);
 407                pr_debug("LUN_RESET: SCSI-2 Released reservation\n");
 408        }
 409
 410        spin_lock_irq(&dev->stats_lock);
 411        dev->num_resets++;
 412        spin_unlock_irq(&dev->stats_lock);
 413
 414        pr_debug("LUN_RESET: %s for [%s] Complete\n",
 415                        (preempt_and_abort_list) ? "Preempt" : "TMR",
 416                        dev->transport->name);
 417        return 0;
 418}
 419
 420
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