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 (!atomic_read(&deve->ua_count)) {
  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                 atomic_inc_mb(&deve->ua_count);
 158                 return 0;
 159         }
 160         list_add_tail(&ua->ua_nacl_list, &deve->ua_list);
 161         spin_unlock(&deve->ua_lock);
 162
 163         pr_debug("Allocated UNIT ATTENTION, mapped LUN: %llu, ASC:"
 164                 " 0x%02x, ASCQ: 0x%02x\n", deve->mapped_lun,
 165                 asc, ascq);
 166
 167         atomic_inc_mb(&deve->ua_count);
 168         return 0;
 169 }
 170
 171 void target_ua_allocate_lun(struct se_node_acl *nacl,
 172                             u32 unpacked_lun, u8 asc, u8 ascq)
 173 {
 174         struct se_dev_entry *deve;
 175
 176         if (!nacl)
 177                 return;
 178
 179         rcu_read_lock();
 180         deve = target_nacl_find_deve(nacl, unpacked_lun);
 181         if (!deve) {
 182                 rcu_read_unlock();
 183                 return;
 184         }
 185
 186         core_scsi3_ua_allocate(deve, asc, ascq);
 187         rcu_read_unlock();
 188 }
 189
 190 void core_scsi3_ua_release_all(
 191         struct se_dev_entry *deve)
 192 {
 193         struct se_ua *ua, *ua_p;
 194
 195         spin_lock(&deve->ua_lock);
 196         list_for_each_entry_safe(ua, ua_p, &deve->ua_list, ua_nacl_list) {
 197                 list_del(&ua->ua_nacl_list);
 198                 kmem_cache_free(se_ua_cache, ua);
 199
 200                 atomic_dec_mb(&deve->ua_count);
 201         }
 202         spin_unlock(&deve->ua_lock);
 203 }
 204
 205 void core_scsi3_ua_for_check_condition(
 206         struct se_cmd *cmd,
 207         u8 *asc,
 208         u8 *ascq)
 209 {
 210         struct se_device *dev = cmd->se_dev;
 211         struct se_dev_entry *deve;
 212         struct se_session *sess = cmd->se_sess;
 213         struct se_node_acl *nacl;
 214         struct se_ua *ua = NULL, *ua_p;
 215         int head = 1;
 216
 217         if (!sess)
 218                 return;
 219
 220         nacl = sess->se_node_acl;
 221         if (!nacl)
 222                 return;
 223
 224         rcu_read_lock();
 225         deve = target_nacl_find_deve(nacl, cmd->orig_fe_lun);
 226         if (!deve) {
 227                 rcu_read_unlock();
 228                 return;
 229         }
 230         if (!atomic_read(&deve->ua_count)) {
 231                 rcu_read_unlock();
 232                 return;
 233         }
 234         /*
 235          * The highest priority Unit Attentions are placed at the head of the
 236          * struct se_dev_entry->ua_list, and will be returned in CHECK_CONDITION +
 237          * sense data for the received CDB.
 238          */
 239         spin_lock(&deve->ua_lock);
 240         list_for_each_entry_safe(ua, ua_p, &deve->ua_list, ua_nacl_list) {
 241                 /*
 242                  * For ua_intlck_ctrl code not equal to 00b, only report the
 243                  * highest priority UNIT_ATTENTION and ASC/ASCQ without
 244                  * clearing it.
 245                  */
 246                 if (dev->dev_attrib.emulate_ua_intlck_ctrl != 0) {
 247                         *asc = ua->ua_asc;
 248                         *ascq = ua->ua_ascq;
 249                         break;
 250                 }
 251                 /*
 252                  * Otherwise for the default 00b, release the UNIT ATTENTION
 253                  * condition.  Return the ASC/ASCQ of the highest priority UA
 254                  * (head of the list) in the outgoing CHECK_CONDITION + sense.
 255                  */
 256                 if (head) {
 257                         *asc = ua->ua_asc;
 258                         *ascq = ua->ua_ascq;
 259                         head = 0;
 260                 }
 261                 list_del(&ua->ua_nacl_list);
 262                 kmem_cache_free(se_ua_cache, ua);
 263
 264                 atomic_dec_mb(&deve->ua_count);
 265         }
 266         spin_unlock(&deve->ua_lock);
 267         rcu_read_unlock();
 268
 269         pr_debug("[%s]: %s UNIT ATTENTION condition with"
 270                 " INTLCK_CTRL: %d, mapped LUN: %llu, got CDB: 0x%02x"
 271                 " reported ASC: 0x%02x, ASCQ: 0x%02x\n",
 272                 nacl->se_tpg->se_tpg_tfo->get_fabric_name(),
 273                 (dev->dev_attrib.emulate_ua_intlck_ctrl != 0) ? "Reporting" :
 274                 "Releasing", dev->dev_attrib.emulate_ua_intlck_ctrl,
 275                 cmd->orig_fe_lun, cmd->t_task_cdb[0], *asc, *ascq);
 276 }
 277
 278 int core_scsi3_ua_clear_for_request_sense(
 279         struct se_cmd *cmd,
 280         u8 *asc,
 281         u8 *ascq)
 282 {
 283         struct se_dev_entry *deve;
 284         struct se_session *sess = cmd->se_sess;
 285         struct se_node_acl *nacl;
 286         struct se_ua *ua = NULL, *ua_p;
 287         int head = 1;
 288
 289         if (!sess)
 290                 return -EINVAL;
 291
 292         nacl = sess->se_node_acl;
 293         if (!nacl)
 294                 return -EINVAL;
 295
 296         rcu_read_lock();
 297         deve = target_nacl_find_deve(nacl, cmd->orig_fe_lun);
 298         if (!deve) {
 299                 rcu_read_unlock();
 300                 return -EINVAL;
 301         }
 302         if (!atomic_read(&deve->ua_count)) {
 303                 rcu_read_unlock();
 304                 return -EPERM;
 305         }
 306         /*
 307          * The highest priority Unit Attentions are placed at the head of the
 308          * struct se_dev_entry->ua_list.  The First (and hence highest priority)
 309          * ASC/ASCQ will be returned in REQUEST_SENSE payload data for the
 310          * matching struct se_lun.
 311          *
 312          * Once the returning ASC/ASCQ values are set, we go ahead and
 313          * release all of the Unit Attention conditions for the associated
 314          * struct se_lun.
 315          */
 316         spin_lock(&deve->ua_lock);
 317         list_for_each_entry_safe(ua, ua_p, &deve->ua_list, ua_nacl_list) {
 318                 if (head) {
 319                         *asc = ua->ua_asc;
 320                         *ascq = ua->ua_ascq;
 321                         head = 0;
 322                 }
 323                 list_del(&ua->ua_nacl_list);
 324                 kmem_cache_free(se_ua_cache, ua);
 325
 326                 atomic_dec_mb(&deve->ua_count);
 327         }
 328         spin_unlock(&deve->ua_lock);
 329         rcu_read_unlock();
 330
 331         pr_debug("[%s]: Released UNIT ATTENTION condition, mapped"
 332                 " LUN: %llu, got REQUEST_SENSE reported ASC: 0x%02x,"
 333                 " ASCQ: 0x%02x\n", nacl->se_tpg->se_tpg_tfo->get_fabric_name(),
 334                 cmd->orig_fe_lun, *asc, *ascq);
 335
 336         return (head) ? -EPERM : 0;
 337 }