drivers/target/target_core_ua.c

   1 /*******************************************************************************
   2  * Filename: target_core_ua.c
   3  *
   4  * This file contains logic for SPC-3 Unit Attention emulation
   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 <scsi/scsi.h>
  29 #include <scsi/scsi_cmnd.h>
  30
  31 #include <target/target_core_base.h>
  32 #include <target/target_core_fabric.h>
  33 #include <target/target_core_configfs.h>
  34
  35 #include "target_core_internal.h"
  36 #include "target_core_alua.h"
  37 #include "target_core_pr.h"
  38 #include "target_core_ua.h"
  39
  40 sense_reason_t
  41 target_scsi3_ua_check(struct se_cmd *cmd)
  42 {
  43         struct se_dev_entry *deve;
  44         struct se_session *sess = cmd->se_sess;
  45         struct se_node_acl *nacl;
  46
  47         if (!sess)
  48                 return 0;
  49
  50         nacl = sess->se_node_acl;
  51         if (!nacl)
  52                 return 0;
  53
  54         deve = nacl->device_list[cmd->orig_fe_lun];
  55         if (!atomic_read(&deve->ua_count))
  56                 return 0;
  57         /*
  58          * From sam4r14, section 5.14 Unit attention condition:
  59          *
  60          * a) if an INQUIRY command enters the enabled command state, the
  61          *    device server shall process the INQUIRY command and shall neither
  62          *    report nor clear any unit attention condition;
  63          * b) if a REPORT LUNS command enters the enabled command state, the
  64          *    device server shall process the REPORT LUNS command and shall not
  65          *    report any unit attention condition;
  66          * e) if a REQUEST SENSE command enters the enabled command state while
  67          *    a unit attention condition exists for the SCSI initiator port
  68          *    associated with the I_T nexus on which the REQUEST SENSE command
  69          *    was received, then the device server shall process the command
  70          *    and either:
  71          */
  72         switch (cmd->t_task_cdb[0]) {
  73         case INQUIRY:
  74         case REPORT_LUNS:
  75         case REQUEST_SENSE:
  76                 return 0;
  77         default:
  78                 return TCM_CHECK_CONDITION_UNIT_ATTENTION;
  79         }
  80 }
  81
  82 int core_scsi3_ua_allocate(
  83         struct se_node_acl *nacl,
  84         u32 unpacked_lun,
  85         u8 asc,
  86         u8 ascq)
  87 {
  88         struct se_dev_entry *deve;
  89         struct se_ua *ua, *ua_p, *ua_tmp;
  90         /*
  91          * PASSTHROUGH OPS
  92          */
  93         if (!nacl)
  94                 return -EINVAL;
  95
  96         ua = kmem_cache_zalloc(se_ua_cache, GFP_ATOMIC);
  97         if (!ua) {
  98                 pr_err("Unable to allocate struct se_ua\n");
  99                 return -ENOMEM;
 100         }
 101         INIT_LIST_HEAD(&ua->ua_dev_list);
 102         INIT_LIST_HEAD(&ua->ua_nacl_list);
 103
 104         ua->ua_nacl = nacl;
 105         ua->ua_asc = asc;
 106         ua->ua_ascq = ascq;
 107
 108         spin_lock_irq(&nacl->device_list_lock);
 109         deve = nacl->device_list[unpacked_lun];
 110
 111         spin_lock(&deve->ua_lock);
 112         list_for_each_entry_safe(ua_p, ua_tmp, &deve->ua_list, ua_nacl_list) {
 113                 /*
 114                  * Do not report the same UNIT ATTENTION twice..
 115                  */
 116                 if ((ua_p->ua_asc == asc) && (ua_p->ua_ascq == ascq)) {
 117                         spin_unlock(&deve->ua_lock);
 118                         spin_unlock_irq(&nacl->device_list_lock);
 119                         kmem_cache_free(se_ua_cache, ua);
 120                         return 0;
 121                 }
 122                 /*
 123                  * Attach the highest priority Unit Attention to
 124                  * the head of the list following sam4r14,
 125                  * Section 5.14 Unit Attention Condition:
 126                  *
 127                  * POWER ON, RESET, OR BUS DEVICE RESET OCCURRED highest
 128                  * POWER ON OCCURRED or
 129                  * DEVICE INTERNAL RESET
 130                  * SCSI BUS RESET OCCURRED or
 131                  * MICROCODE HAS BEEN CHANGED or
 132                  * protocol specific
 133                  * BUS DEVICE RESET FUNCTION OCCURRED
 134                  * I_T NEXUS LOSS OCCURRED
 135                  * COMMANDS CLEARED BY POWER LOSS NOTIFICATION
 136                  * all others                                    Lowest
 137                  *
 138                  * Each of the ASCQ codes listed above are defined in
 139                  * the 29h ASC family, see spc4r17 Table D.1
 140                  */
 141                 if (ua_p->ua_asc == 0x29) {
 142                         if ((asc == 0x29) && (ascq > ua_p->ua_ascq))
 143                                 list_add(&ua->ua_nacl_list,
 144                                                 &deve->ua_list);
 145                         else
 146                                 list_add_tail(&ua->ua_nacl_list,
 147                                                 &deve->ua_list);
 148                 } else if (ua_p->ua_asc == 0x2a) {
 149                         /*
 150                          * Incoming Family 29h ASCQ codes will override
 151                          * Family 2AHh ASCQ codes for Unit Attention condition.
 152                          */
 153                         if ((asc == 0x29) || (ascq > ua_p->ua_asc))
 154                                 list_add(&ua->ua_nacl_list,
 155                                         &deve->ua_list);
 156                         else
 157                                 list_add_tail(&ua->ua_nacl_list,
 158                                                 &deve->ua_list);
 159                 } else
 160                         list_add_tail(&ua->ua_nacl_list,
 161                                 &deve->ua_list);
 162                 spin_unlock(&deve->ua_lock);
 163                 spin_unlock_irq(&nacl->device_list_lock);
 164
 165                 atomic_inc(&deve->ua_count);
 166                 smp_mb__after_atomic_inc();
 167                 return 0;
 168         }
 169         list_add_tail(&ua->ua_nacl_list, &deve->ua_list);
 170         spin_unlock(&deve->ua_lock);
 171         spin_unlock_irq(&nacl->device_list_lock);
 172
 173         pr_debug("[%s]: Allocated UNIT ATTENTION, mapped LUN: %u, ASC:"
 174                 " 0x%02x, ASCQ: 0x%02x\n",
 175                 nacl->se_tpg->se_tpg_tfo->get_fabric_name(), unpacked_lun,
 176                 asc, ascq);
 177
 178         atomic_inc(&deve->ua_count);
 179         smp_mb__after_atomic_inc();
 180         return 0;
 181 }
 182
 183 void core_scsi3_ua_release_all(
 184         struct se_dev_entry *deve)
 185 {
 186         struct se_ua *ua, *ua_p;
 187
 188         spin_lock(&deve->ua_lock);
 189         list_for_each_entry_safe(ua, ua_p, &deve->ua_list, ua_nacl_list) {
 190                 list_del(&ua->ua_nacl_list);
 191                 kmem_cache_free(se_ua_cache, ua);
 192
 193                 atomic_dec(&deve->ua_count);
 194                 smp_mb__after_atomic_dec();
 195         }
 196         spin_unlock(&deve->ua_lock);
 197 }
 198
 199 void core_scsi3_ua_for_check_condition(
 200         struct se_cmd *cmd,
 201         u8 *asc,
 202         u8 *ascq)
 203 {
 204         struct se_device *dev = cmd->se_dev;
 205         struct se_dev_entry *deve;
 206         struct se_session *sess = cmd->se_sess;
 207         struct se_node_acl *nacl;
 208         struct se_ua *ua = NULL, *ua_p;
 209         int head = 1;
 210
 211         if (!sess)
 212                 return;
 213
 214         nacl = sess->se_node_acl;
 215         if (!nacl)
 216                 return;
 217
 218         spin_lock_irq(&nacl->device_list_lock);
 219         deve = nacl->device_list[cmd->orig_fe_lun];
 220         if (!atomic_read(&deve->ua_count)) {
 221                 spin_unlock_irq(&nacl->device_list_lock);
 222                 return;
 223         }
 224         /*
 225          * The highest priority Unit Attentions are placed at the head of the
 226          * struct se_dev_entry->ua_list, and will be returned in CHECK_CONDITION +
 227          * sense data for the received CDB.
 228          */
 229         spin_lock(&deve->ua_lock);
 230         list_for_each_entry_safe(ua, ua_p, &deve->ua_list, ua_nacl_list) {
 231                 /*
 232                  * For ua_intlck_ctrl code not equal to 00b, only report the
 233                  * highest priority UNIT_ATTENTION and ASC/ASCQ without
 234                  * clearing it.
 235                  */
 236                 if (dev->dev_attrib.emulate_ua_intlck_ctrl != 0) {
 237                         *asc = ua->ua_asc;
 238                         *ascq = ua->ua_ascq;
 239                         break;
 240                 }
 241                 /*
 242                  * Otherwise for the default 00b, release the UNIT ATTENTION
 243                  * condition.  Return the ASC/ASCQ of the highest priority UA
 244                  * (head of the list) in the outgoing CHECK_CONDITION + sense.
 245                  */
 246                 if (head) {
 247                         *asc = ua->ua_asc;
 248                         *ascq = ua->ua_ascq;
 249                         head = 0;
 250                 }
 251                 list_del(&ua->ua_nacl_list);
 252                 kmem_cache_free(se_ua_cache, ua);
 253
 254                 atomic_dec(&deve->ua_count);
 255                 smp_mb__after_atomic_dec();
 256         }
 257         spin_unlock(&deve->ua_lock);
 258         spin_unlock_irq(&nacl->device_list_lock);
 259
 260         pr_debug("[%s]: %s UNIT ATTENTION condition with"
 261                 " INTLCK_CTRL: %d, mapped LUN: %u, got CDB: 0x%02x"
 262                 " reported ASC: 0x%02x, ASCQ: 0x%02x\n",
 263                 nacl->se_tpg->se_tpg_tfo->get_fabric_name(),
 264                 (dev->dev_attrib.emulate_ua_intlck_ctrl != 0) ? "Reporting" :
 265                 "Releasing", dev->dev_attrib.emulate_ua_intlck_ctrl,
 266                 cmd->orig_fe_lun, cmd->t_task_cdb[0], *asc, *ascq);
 267 }
 268
 269 int core_scsi3_ua_clear_for_request_sense(
 270         struct se_cmd *cmd,
 271         u8 *asc,
 272         u8 *ascq)
 273 {
 274         struct se_dev_entry *deve;
 275         struct se_session *sess = cmd->se_sess;
 276         struct se_node_acl *nacl;
 277         struct se_ua *ua = NULL, *ua_p;
 278         int head = 1;
 279
 280         if (!sess)
 281                 return -EINVAL;
 282
 283         nacl = sess->se_node_acl;
 284         if (!nacl)
 285                 return -EINVAL;
 286
 287         spin_lock_irq(&nacl->device_list_lock);
 288         deve = nacl->device_list[cmd->orig_fe_lun];
 289         if (!atomic_read(&deve->ua_count)) {
 290                 spin_unlock_irq(&nacl->device_list_lock);
 291                 return -EPERM;
 292         }
 293         /*
 294          * The highest priority Unit Attentions are placed at the head of the
 295          * struct se_dev_entry->ua_list.  The First (and hence highest priority)
 296          * ASC/ASCQ will be returned in REQUEST_SENSE payload data for the
 297          * matching struct se_lun.
 298          *
 299          * Once the returning ASC/ASCQ values are set, we go ahead and
 300          * release all of the Unit Attention conditions for the associated
 301          * struct se_lun.
 302          */
 303         spin_lock(&deve->ua_lock);
 304         list_for_each_entry_safe(ua, ua_p, &deve->ua_list, ua_nacl_list) {
 305                 if (head) {
 306                         *asc = ua->ua_asc;
 307                         *ascq = ua->ua_ascq;
 308                         head = 0;
 309                 }
 310                 list_del(&ua->ua_nacl_list);
 311                 kmem_cache_free(se_ua_cache, ua);
 312
 313                 atomic_dec(&deve->ua_count);
 314                 smp_mb__after_atomic_dec();
 315         }
 316         spin_unlock(&deve->ua_lock);
 317         spin_unlock_irq(&nacl->device_list_lock);
 318
 319         pr_debug("[%s]: Released UNIT ATTENTION condition, mapped"
 320                 " LUN: %u, got REQUEST_SENSE reported ASC: 0x%02x,"
 321                 " ASCQ: 0x%02x\n", nacl->se_tpg->se_tpg_tfo->get_fabric_name(),
 322                 cmd->orig_fe_lun, *asc, *ascq);
 323
 324         return (head) ? -EPERM : 0;
 325 }