linux/drivers/target/target_core_ua.c
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   1/*******************************************************************************
   2 * Filename: target_core_ua.c
   3 *
   4 * This file contains logic for SPC-3 Unit Attention emulation
   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 <scsi/scsi.h>
  30#include <scsi/scsi_cmnd.h>
  31
  32#include <target/target_core_base.h>
  33#include <target/target_core_fabric.h>
  34#include <target/target_core_configfs.h>
  35
  36#include "target_core_internal.h"
  37#include "target_core_alua.h"
  38#include "target_core_pr.h"
  39#include "target_core_ua.h"
  40
  41int core_scsi3_ua_check(
  42        struct se_cmd *cmd,
  43        unsigned char *cdb)
  44{
  45        struct se_dev_entry *deve;
  46        struct se_session *sess = cmd->se_sess;
  47        struct se_node_acl *nacl;
  48
  49        if (!sess)
  50                return 0;
  51
  52        nacl = sess->se_node_acl;
  53        if (!nacl)
  54                return 0;
  55
  56        deve = nacl->device_list[cmd->orig_fe_lun];
  57        if (!atomic_read(&deve->ua_count))
  58                return 0;
  59        /*
  60         * From sam4r14, section 5.14 Unit attention condition:
  61         *
  62         * a) if an INQUIRY command enters the enabled command state, the
  63         *    device server shall process the INQUIRY command and shall neither
  64         *    report nor clear any unit attention condition;
  65         * b) if a REPORT LUNS command enters the enabled command state, the
  66         *    device server shall process the REPORT LUNS command and shall not
  67         *    report any unit attention condition;
  68         * e) if a REQUEST SENSE command enters the enabled command state while
  69         *    a unit attention condition exists for the SCSI initiator port
  70         *    associated with the I_T nexus on which the REQUEST SENSE command
  71         *    was received, then the device server shall process the command
  72         *    and either:
  73         */
  74        switch (cdb[0]) {
  75        case INQUIRY:
  76        case REPORT_LUNS:
  77        case REQUEST_SENSE:
  78                return 0;
  79        default:
  80                return -EINVAL;
  81        }
  82
  83        return -EINVAL;
  84}
  85
  86int core_scsi3_ua_allocate(
  87        struct se_node_acl *nacl,
  88        u32 unpacked_lun,
  89        u8 asc,
  90        u8 ascq)
  91{
  92        struct se_dev_entry *deve;
  93        struct se_ua *ua, *ua_p, *ua_tmp;
  94        /*
  95         * PASSTHROUGH OPS
  96         */
  97        if (!nacl)
  98                return -EINVAL;
  99
 100        ua = kmem_cache_zalloc(se_ua_cache, GFP_ATOMIC);
 101        if (!ua) {
 102                pr_err("Unable to allocate struct se_ua\n");
 103                return -ENOMEM;
 104        }
 105        INIT_LIST_HEAD(&ua->ua_dev_list);
 106        INIT_LIST_HEAD(&ua->ua_nacl_list);
 107
 108        ua->ua_nacl = nacl;
 109        ua->ua_asc = asc;
 110        ua->ua_ascq = ascq;
 111
 112        spin_lock_irq(&nacl->device_list_lock);
 113        deve = nacl->device_list[unpacked_lun];
 114
 115        spin_lock(&deve->ua_lock);
 116        list_for_each_entry_safe(ua_p, ua_tmp, &deve->ua_list, ua_nacl_list) {
 117                /*
 118                 * Do not report the same UNIT ATTENTION twice..
 119                 */
 120                if ((ua_p->ua_asc == asc) && (ua_p->ua_ascq == ascq)) {
 121                        spin_unlock(&deve->ua_lock);
 122                        spin_unlock_irq(&nacl->device_list_lock);
 123                        kmem_cache_free(se_ua_cache, ua);
 124                        return 0;
 125                }
 126                /*
 127                 * Attach the highest priority Unit Attention to
 128                 * the head of the list following sam4r14,
 129                 * Section 5.14 Unit Attention Condition:
 130                 *
 131                 * POWER ON, RESET, OR BUS DEVICE RESET OCCURRED highest
 132                 * POWER ON OCCURRED or
 133                 * DEVICE INTERNAL RESET
 134                 * SCSI BUS RESET OCCURRED or
 135                 * MICROCODE HAS BEEN CHANGED or
 136                 * protocol specific
 137                 * BUS DEVICE RESET FUNCTION OCCURRED
 138                 * I_T NEXUS LOSS OCCURRED
 139                 * COMMANDS CLEARED BY POWER LOSS NOTIFICATION
 140                 * all others                                    Lowest
 141                 *
 142                 * Each of the ASCQ codes listed above are defined in
 143                 * the 29h ASC family, see spc4r17 Table D.1
 144                 */
 145                if (ua_p->ua_asc == 0x29) {
 146                        if ((asc == 0x29) && (ascq > ua_p->ua_ascq))
 147                                list_add(&ua->ua_nacl_list,
 148                                                &deve->ua_list);
 149                        else
 150                                list_add_tail(&ua->ua_nacl_list,
 151                                                &deve->ua_list);
 152                } else if (ua_p->ua_asc == 0x2a) {
 153                        /*
 154                         * Incoming Family 29h ASCQ codes will override
 155                         * Family 2AHh ASCQ codes for Unit Attention condition.
 156                         */
 157                        if ((asc == 0x29) || (ascq > ua_p->ua_asc))
 158                                list_add(&ua->ua_nacl_list,
 159                                        &deve->ua_list);
 160                        else
 161                                list_add_tail(&ua->ua_nacl_list,
 162                                                &deve->ua_list);
 163                } else
 164                        list_add_tail(&ua->ua_nacl_list,
 165                                &deve->ua_list);
 166                spin_unlock(&deve->ua_lock);
 167                spin_unlock_irq(&nacl->device_list_lock);
 168
 169                atomic_inc(&deve->ua_count);
 170                smp_mb__after_atomic_inc();
 171                return 0;
 172        }
 173        list_add_tail(&ua->ua_nacl_list, &deve->ua_list);
 174        spin_unlock(&deve->ua_lock);
 175        spin_unlock_irq(&nacl->device_list_lock);
 176
 177        pr_debug("[%s]: Allocated UNIT ATTENTION, mapped LUN: %u, ASC:"
 178                " 0x%02x, ASCQ: 0x%02x\n",
 179                nacl->se_tpg->se_tpg_tfo->get_fabric_name(), unpacked_lun,
 180                asc, ascq);
 181
 182        atomic_inc(&deve->ua_count);
 183        smp_mb__after_atomic_inc();
 184        return 0;
 185}
 186
 187void core_scsi3_ua_release_all(
 188        struct se_dev_entry *deve)
 189{
 190        struct se_ua *ua, *ua_p;
 191
 192        spin_lock(&deve->ua_lock);
 193        list_for_each_entry_safe(ua, ua_p, &deve->ua_list, ua_nacl_list) {
 194                list_del(&ua->ua_nacl_list);
 195                kmem_cache_free(se_ua_cache, ua);
 196
 197                atomic_dec(&deve->ua_count);
 198                smp_mb__after_atomic_dec();
 199        }
 200        spin_unlock(&deve->ua_lock);
 201}
 202
 203void core_scsi3_ua_for_check_condition(
 204        struct se_cmd *cmd,
 205        u8 *asc,
 206        u8 *ascq)
 207{
 208        struct se_device *dev = cmd->se_dev;
 209        struct se_dev_entry *deve;
 210        struct se_session *sess = cmd->se_sess;
 211        struct se_node_acl *nacl;
 212        struct se_ua *ua = NULL, *ua_p;
 213        int head = 1;
 214
 215        if (!sess)
 216                return;
 217
 218        nacl = sess->se_node_acl;
 219        if (!nacl)
 220                return;
 221
 222        spin_lock_irq(&nacl->device_list_lock);
 223        deve = nacl->device_list[cmd->orig_fe_lun];
 224        if (!atomic_read(&deve->ua_count)) {
 225                spin_unlock_irq(&nacl->device_list_lock);
 226                return;
 227        }
 228        /*
 229         * The highest priority Unit Attentions are placed at the head of the
 230         * struct se_dev_entry->ua_list, and will be returned in CHECK_CONDITION +
 231         * sense data for the received CDB.
 232         */
 233        spin_lock(&deve->ua_lock);
 234        list_for_each_entry_safe(ua, ua_p, &deve->ua_list, ua_nacl_list) {
 235                /*
 236                 * For ua_intlck_ctrl code not equal to 00b, only report the
 237                 * highest priority UNIT_ATTENTION and ASC/ASCQ without
 238                 * clearing it.
 239                 */
 240                if (dev->se_sub_dev->se_dev_attrib.emulate_ua_intlck_ctrl != 0) {
 241                        *asc = ua->ua_asc;
 242                        *ascq = ua->ua_ascq;
 243                        break;
 244                }
 245                /*
 246                 * Otherwise for the default 00b, release the UNIT ATTENTION
 247                 * condition.  Return the ASC/ASCQ of the highest priority UA
 248                 * (head of the list) in the outgoing CHECK_CONDITION + sense.
 249                 */
 250                if (head) {
 251                        *asc = ua->ua_asc;
 252                        *ascq = ua->ua_ascq;
 253                        head = 0;
 254                }
 255                list_del(&ua->ua_nacl_list);
 256                kmem_cache_free(se_ua_cache, ua);
 257
 258                atomic_dec(&deve->ua_count);
 259                smp_mb__after_atomic_dec();
 260        }
 261        spin_unlock(&deve->ua_lock);
 262        spin_unlock_irq(&nacl->device_list_lock);
 263
 264        pr_debug("[%s]: %s UNIT ATTENTION condition with"
 265                " INTLCK_CTRL: %d, mapped LUN: %u, got CDB: 0x%02x"
 266                " reported ASC: 0x%02x, ASCQ: 0x%02x\n",
 267                nacl->se_tpg->se_tpg_tfo->get_fabric_name(),
 268                (dev->se_sub_dev->se_dev_attrib.emulate_ua_intlck_ctrl != 0) ? "Reporting" :
 269                "Releasing", dev->se_sub_dev->se_dev_attrib.emulate_ua_intlck_ctrl,
 270                cmd->orig_fe_lun, cmd->t_task_cdb[0], *asc, *ascq);
 271}
 272
 273int core_scsi3_ua_clear_for_request_sense(
 274        struct se_cmd *cmd,
 275        u8 *asc,
 276        u8 *ascq)
 277{
 278        struct se_dev_entry *deve;
 279        struct se_session *sess = cmd->se_sess;
 280        struct se_node_acl *nacl;
 281        struct se_ua *ua = NULL, *ua_p;
 282        int head = 1;
 283
 284        if (!sess)
 285                return -EINVAL;
 286
 287        nacl = sess->se_node_acl;
 288        if (!nacl)
 289                return -EINVAL;
 290
 291        spin_lock_irq(&nacl->device_list_lock);
 292        deve = nacl->device_list[cmd->orig_fe_lun];
 293        if (!atomic_read(&deve->ua_count)) {
 294                spin_unlock_irq(&nacl->device_list_lock);
 295                return -EPERM;
 296        }
 297        /*
 298         * The highest priority Unit Attentions are placed at the head of the
 299         * struct se_dev_entry->ua_list.  The First (and hence highest priority)
 300         * ASC/ASCQ will be returned in REQUEST_SENSE payload data for the
 301         * matching struct se_lun.
 302         *
 303         * Once the returning ASC/ASCQ values are set, we go ahead and
 304         * release all of the Unit Attention conditions for the associated
 305         * struct se_lun.
 306         */
 307        spin_lock(&deve->ua_lock);
 308        list_for_each_entry_safe(ua, ua_p, &deve->ua_list, ua_nacl_list) {
 309                if (head) {
 310                        *asc = ua->ua_asc;
 311                        *ascq = ua->ua_ascq;
 312                        head = 0;
 313                }
 314                list_del(&ua->ua_nacl_list);
 315                kmem_cache_free(se_ua_cache, ua);
 316
 317                atomic_dec(&deve->ua_count);
 318                smp_mb__after_atomic_dec();
 319        }
 320        spin_unlock(&deve->ua_lock);
 321        spin_unlock_irq(&nacl->device_list_lock);
 322
 323        pr_debug("[%s]: Released UNIT ATTENTION condition, mapped"
 324                " LUN: %u, got REQUEST_SENSE reported ASC: 0x%02x,"
 325                " ASCQ: 0x%02x\n", nacl->se_tpg->se_tpg_tfo->get_fabric_name(),
 326                cmd->orig_fe_lun, *asc, *ascq);
 327
 328        return (head) ? -EPERM : 0;
 329}
 330
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