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_proto.h>
  29
  30 #include <target/target_core_base.h>
  31 #include <target/target_core_fabric.h>
  32
  33 #include "target_core_internal.h"
  34 #include "target_core_alua.h"
  35 #include "target_core_pr.h"
  36 #include "target_core_ua.h"
  37
  38 sense_reason_t
  39 target_scsi3_ua_check(struct se_cmd *cmd)
  40 {
  41         struct se_dev_entry *deve;
  42         struct se_session *sess = cmd->se_sess;
  43         struct se_node_acl *nacl;
  44
  45         if (!sess)
  46                 return 0;
  47
  48         nacl = sess->se_node_acl;
  49         if (!nacl)
  50                 return 0;
  51
  52         rcu_read_lock();
  53         deve = target_nacl_find_deve(nacl, cmd->orig_fe_lun);
  54         if (!deve) {
  55                 rcu_read_unlock();
  56                 return 0;
  57         }
  58         if (list_empty_careful(&deve->ua_list)) {
  59                 rcu_read_unlock();
  60                 return 0;
  61         }
  62         rcu_read_unlock();
  63         /*
  64          * From sam4r14, section 5.14 Unit attention condition:
  65          *
  66          * a) if an INQUIRY command enters the enabled command state, the
  67          *    device server shall process the INQUIRY command and shall neither
  68          *    report nor clear any unit attention condition;
  69          * b) if a REPORT LUNS command enters the enabled command state, the
  70          *    device server shall process the REPORT LUNS command and shall not
  71          *    report any unit attention condition;
  72          * e) if a REQUEST SENSE command enters the enabled command state while
  73          *    a unit attention condition exists for the SCSI initiator port
  74          *    associated with the I_T nexus on which the REQUEST SENSE command
  75          *    was received, then the device server shall process the command
  76          *    and either:
  77          */
  78         switch (cmd->t_task_cdb[0]) {
  79         case INQUIRY:
  80         case REPORT_LUNS:
  81         case REQUEST_SENSE:
  82                 return 0;
  83         default:
  84                 return TCM_CHECK_CONDITION_UNIT_ATTENTION;
  85         }
  86 }
  87
  88 int core_scsi3_ua_allocate(
  89         struct se_dev_entry *deve,
  90         u8 asc,
  91         u8 ascq)
  92 {
  93         struct se_ua *ua, *ua_p, *ua_tmp;
  94
  95         ua = kmem_cache_zalloc(se_ua_cache, GFP_ATOMIC);
  96         if (!ua) {
  97                 pr_err("Unable to allocate struct se_ua\n");
  98                 return -ENOMEM;
  99         }
 100         INIT_LIST_HEAD(&ua->ua_nacl_list);
 101
 102         ua->ua_asc = asc;
 103         ua->ua_ascq = ascq;
 104
 105         spin_lock(&deve->ua_lock);
 106         list_for_each_entry_safe(ua_p, ua_tmp, &deve->ua_list, ua_nacl_list) {
 107                 /*
 108                  * Do not report the same UNIT ATTENTION twice..
 109                  */
 110                 if ((ua_p->ua_asc == asc) && (ua_p->ua_ascq == ascq)) {
 111                         spin_unlock(&deve->ua_lock);
 112                         kmem_cache_free(se_ua_cache, ua);
 113                         return 0;
 114                 }
 115                 /*
 116                  * Attach the highest priority Unit Attention to
 117                  * the head of the list following sam4r14,
 118                  * Section 5.14 Unit Attention Condition:
 119                  *
 120                  * POWER ON, RESET, OR BUS DEVICE RESET OCCURRED highest
 121                  * POWER ON OCCURRED or
 122                  * DEVICE INTERNAL RESET
 123                  * SCSI BUS RESET OCCURRED or
 124                  * MICROCODE HAS BEEN CHANGED or
 125                  * protocol specific
 126                  * BUS DEVICE RESET FUNCTION OCCURRED
 127                  * I_T NEXUS LOSS OCCURRED
 128                  * COMMANDS CLEARED BY POWER LOSS NOTIFICATION
 129                  * all others                                    Lowest
 130                  *
 131                  * Each of the ASCQ codes listed above are defined in
 132                  * the 29h ASC family, see spc4r17 Table D.1
 133                  */
 134                 if (ua_p->ua_asc == 0x29) {
 135                         if ((asc == 0x29) && (ascq > ua_p->ua_ascq))
 136                                 list_add(&ua->ua_nacl_list,
 137                                                 &deve->ua_list);
 138                         else
 139                                 list_add_tail(&ua->ua_nacl_list,
 140                                                 &deve->ua_list);
 141                 } else if (ua_p->ua_asc == 0x2a) {
 142                         /*
 143                          * Incoming Family 29h ASCQ codes will override
 144                          * Family 2AHh ASCQ codes for Unit Attention condition.
 145                          */
 146                         if ((asc == 0x29) || (ascq > ua_p->ua_asc))
 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
 153                         list_add_tail(&ua->ua_nacl_list,
 154                                 &deve->ua_list);
 155                 spin_unlock(&deve->ua_lock);
 156
 157                 return 0;
 158         }
 159         list_add_tail(&ua->ua_nacl_list, &deve->ua_list);
 160         spin_unlock(&deve->ua_lock);
 161
 162         pr_debug("Allocated UNIT ATTENTION, mapped LUN: %llu, ASC:"
 163                 " 0x%02x, ASCQ: 0x%02x\n", deve->mapped_lun,
 164                 asc, ascq);
 165
 166         return 0;
 167 }
 168
 169 void target_ua_allocate_lun(struct se_node_acl *nacl,
 170                             u32 unpacked_lun, u8 asc, u8 ascq)
 171 {
 172         struct se_dev_entry *deve;
 173
 174         if (!nacl)
 175                 return;
 176
 177         rcu_read_lock();
 178         deve = target_nacl_find_deve(nacl, unpacked_lun);
 179         if (!deve) {
 180                 rcu_read_unlock();
 181                 return;
 182         }
 183
 184         core_scsi3_ua_allocate(deve, asc, ascq);
 185         rcu_read_unlock();
 186 }
 187
 188 void core_scsi3_ua_release_all(
 189         struct se_dev_entry *deve)
 190 {
 191         struct se_ua *ua, *ua_p;
 192
 193         spin_lock(&deve->ua_lock);
 194         list_for_each_entry_safe(ua, ua_p, &deve->ua_list, ua_nacl_list) {
 195                 list_del(&ua->ua_nacl_list);
 196                 kmem_cache_free(se_ua_cache, ua);
 197         }
 198         spin_unlock(&deve->ua_lock);
 199 }
 200
 201 /*
 202  * Dequeue a unit attention from the unit attention list. This function
 203  * returns true if the dequeuing succeeded and if *@key, *@asc and *@ascq have
 204  * been set.
 205  */
 206 bool core_scsi3_ua_for_check_condition(struct se_cmd *cmd, u8 *key, u8 *asc,
 207                                        u8 *ascq)
 208 {
 209         struct se_device *dev = cmd->se_dev;
 210         struct se_dev_entry *deve;
 211         struct se_session *sess = cmd->se_sess;
 212         struct se_node_acl *nacl;
 213         struct se_ua *ua = NULL, *ua_p;
 214         int head = 1;
 215
 216         if (WARN_ON_ONCE(!sess))
 217                 return false;
 218
 219         nacl = sess->se_node_acl;
 220         if (WARN_ON_ONCE(!nacl))
 221                 return false;
 222
 223         rcu_read_lock();
 224         deve = target_nacl_find_deve(nacl, cmd->orig_fe_lun);
 225         if (!deve) {
 226                 rcu_read_unlock();
 227                 *key = ILLEGAL_REQUEST;
 228                 *asc = 0x25; /* LOGICAL UNIT NOT SUPPORTED */
 229                 *ascq = 0;
 230                 return true;
 231         }
 232         *key = UNIT_ATTENTION;
 233         /*
 234          * The highest priority Unit Attentions are placed at the head of the
 235          * struct se_dev_entry->ua_list, and will be returned in CHECK_CONDITION +
 236          * sense data for the received CDB.
 237          */
 238         spin_lock(&deve->ua_lock);
 239         list_for_each_entry_safe(ua, ua_p, &deve->ua_list, ua_nacl_list) {
 240                 /*
 241                  * For ua_intlck_ctrl code not equal to 00b, only report the
 242                  * highest priority UNIT_ATTENTION and ASC/ASCQ without
 243                  * clearing it.
 244                  */
 245                 if (dev->dev_attrib.emulate_ua_intlck_ctrl != 0) {
 246                         *asc = ua->ua_asc;
 247                         *ascq = ua->ua_ascq;
 248                         break;
 249                 }
 250                 /*
 251                  * Otherwise for the default 00b, release the UNIT ATTENTION
 252                  * condition.  Return the ASC/ASCQ of the highest priority UA
 253                  * (head of the list) in the outgoing CHECK_CONDITION + sense.
 254                  */
 255                 if (head) {
 256                         *asc = ua->ua_asc;
 257                         *ascq = ua->ua_ascq;
 258                         head = 0;
 259                 }
 260                 list_del(&ua->ua_nacl_list);
 261                 kmem_cache_free(se_ua_cache, ua);
 262         }
 263         spin_unlock(&deve->ua_lock);
 264         rcu_read_unlock();
 265
 266         pr_debug("[%s]: %s UNIT ATTENTION condition with"
 267                 " INTLCK_CTRL: %d, mapped LUN: %llu, got CDB: 0x%02x"
 268                 " reported ASC: 0x%02x, ASCQ: 0x%02x\n",
 269                 nacl->se_tpg->se_tpg_tfo->get_fabric_name(),
 270                 (dev->dev_attrib.emulate_ua_intlck_ctrl != 0) ? "Reporting" :
 271                 "Releasing", dev->dev_attrib.emulate_ua_intlck_ctrl,
 272                 cmd->orig_fe_lun, cmd->t_task_cdb[0], *asc, *ascq);
 273
 274         return head == 0;
 275 }
 276
 277 int core_scsi3_ua_clear_for_request_sense(
 278         struct se_cmd *cmd,
 279         u8 *asc,
 280         u8 *ascq)
 281 {
 282         struct se_dev_entry *deve;
 283         struct se_session *sess = cmd->se_sess;
 284         struct se_node_acl *nacl;
 285         struct se_ua *ua = NULL, *ua_p;
 286         int head = 1;
 287
 288         if (!sess)
 289                 return -EINVAL;
 290
 291         nacl = sess->se_node_acl;
 292         if (!nacl)
 293                 return -EINVAL;
 294
 295         rcu_read_lock();
 296         deve = target_nacl_find_deve(nacl, cmd->orig_fe_lun);
 297         if (!deve) {
 298                 rcu_read_unlock();
 299                 return -EINVAL;
 300         }
 301         if (list_empty_careful(&deve->ua_list)) {
 302                 rcu_read_unlock();
 303                 return -EPERM;
 304         }
 305         /*
 306          * The highest priority Unit Attentions are placed at the head of the
 307          * struct se_dev_entry->ua_list.  The First (and hence highest priority)
 308          * ASC/ASCQ will be returned in REQUEST_SENSE payload data for the
 309          * matching struct se_lun.
 310          *
 311          * Once the returning ASC/ASCQ values are set, we go ahead and
 312          * release all of the Unit Attention conditions for the associated
 313          * struct se_lun.
 314          */
 315         spin_lock(&deve->ua_lock);
 316         list_for_each_entry_safe(ua, ua_p, &deve->ua_list, ua_nacl_list) {
 317                 if (head) {
 318                         *asc = ua->ua_asc;
 319                         *ascq = ua->ua_ascq;
 320                         head = 0;
 321                 }
 322                 list_del(&ua->ua_nacl_list);
 323                 kmem_cache_free(se_ua_cache, ua);
 324         }
 325         spin_unlock(&deve->ua_lock);
 326         rcu_read_unlock();
 327
 328         pr_debug("[%s]: Released UNIT ATTENTION condition, mapped"
 329                 " LUN: %llu, got REQUEST_SENSE reported ASC: 0x%02x,"
 330                 " ASCQ: 0x%02x\n", nacl->se_tpg->se_tpg_tfo->get_fabric_name(),
 331                 cmd->orig_fe_lun, *asc, *ascq);
 332
 333         return (head) ? -EPERM : 0;
 334 }