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  * 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
  41 int 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
  86 int 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
 187 void 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
 203 void 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
 273 int 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 }