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_nacl_list);
 102
 103         ua->ua_nacl = nacl;
 104         ua->ua_asc = asc;
 105         ua->ua_ascq = ascq;
 106
 107         spin_lock_irq(&nacl->device_list_lock);
 108         deve = nacl->device_list[unpacked_lun];
 109
 110         spin_lock(&deve->ua_lock);
 111         list_for_each_entry_safe(ua_p, ua_tmp, &deve->ua_list, ua_nacl_list) {
 112                 /*
 113                  * Do not report the same UNIT ATTENTION twice..
 114                  */
 115                 if ((ua_p->ua_asc == asc) && (ua_p->ua_ascq == ascq)) {
 116                         spin_unlock(&deve->ua_lock);
 117                         spin_unlock_irq(&nacl->device_list_lock);
 118                         kmem_cache_free(se_ua_cache, ua);
 119                         return 0;
 120                 }
 121                 /*
 122                  * Attach the highest priority Unit Attention to
 123                  * the head of the list following sam4r14,
 124                  * Section 5.14 Unit Attention Condition:
 125                  *
 126                  * POWER ON, RESET, OR BUS DEVICE RESET OCCURRED highest
 127                  * POWER ON OCCURRED or
 128                  * DEVICE INTERNAL RESET
 129                  * SCSI BUS RESET OCCURRED or
 130                  * MICROCODE HAS BEEN CHANGED or
 131                  * protocol specific
 132                  * BUS DEVICE RESET FUNCTION OCCURRED
 133                  * I_T NEXUS LOSS OCCURRED
 134                  * COMMANDS CLEARED BY POWER LOSS NOTIFICATION
 135                  * all others                                    Lowest
 136                  *
 137                  * Each of the ASCQ codes listed above are defined in
 138                  * the 29h ASC family, see spc4r17 Table D.1
 139                  */
 140                 if (ua_p->ua_asc == 0x29) {
 141                         if ((asc == 0x29) && (ascq > ua_p->ua_ascq))
 142                                 list_add(&ua->ua_nacl_list,
 143                                                 &deve->ua_list);
 144                         else
 145                                 list_add_tail(&ua->ua_nacl_list,
 146                                                 &deve->ua_list);
 147                 } else if (ua_p->ua_asc == 0x2a) {
 148                         /*
 149                          * Incoming Family 29h ASCQ codes will override
 150                          * Family 2AHh ASCQ codes for Unit Attention condition.
 151                          */
 152                         if ((asc == 0x29) || (ascq > ua_p->ua_asc))
 153                                 list_add(&ua->ua_nacl_list,
 154                                         &deve->ua_list);
 155                         else
 156                                 list_add_tail(&ua->ua_nacl_list,
 157                                                 &deve->ua_list);
 158                 } else
 159                         list_add_tail(&ua->ua_nacl_list,
 160                                 &deve->ua_list);
 161                 spin_unlock(&deve->ua_lock);
 162                 spin_unlock_irq(&nacl->device_list_lock);
 163
 164                 atomic_inc(&deve->ua_count);
 165                 smp_mb__after_atomic_inc();
 166                 return 0;
 167         }
 168         list_add_tail(&ua->ua_nacl_list, &deve->ua_list);
 169         spin_unlock(&deve->ua_lock);
 170         spin_unlock_irq(&nacl->device_list_lock);
 171
 172         pr_debug("[%s]: Allocated UNIT ATTENTION, mapped LUN: %u, ASC:"
 173                 " 0x%02x, ASCQ: 0x%02x\n",
 174                 nacl->se_tpg->se_tpg_tfo->get_fabric_name(), unpacked_lun,
 175                 asc, ascq);
 176
 177         atomic_inc(&deve->ua_count);
 178         smp_mb__after_atomic_inc();
 179         return 0;
 180 }
 181
 182 void core_scsi3_ua_release_all(
 183         struct se_dev_entry *deve)
 184 {
 185         struct se_ua *ua, *ua_p;
 186
 187         spin_lock(&deve->ua_lock);
 188         list_for_each_entry_safe(ua, ua_p, &deve->ua_list, ua_nacl_list) {
 189                 list_del(&ua->ua_nacl_list);
 190                 kmem_cache_free(se_ua_cache, ua);
 191
 192                 atomic_dec(&deve->ua_count);
 193                 smp_mb__after_atomic_dec();
 194         }
 195         spin_unlock(&deve->ua_lock);
 196 }
 197
 198 void core_scsi3_ua_for_check_condition(
 199         struct se_cmd *cmd,
 200         u8 *asc,
 201         u8 *ascq)
 202 {
 203         struct se_device *dev = cmd->se_dev;
 204         struct se_dev_entry *deve;
 205         struct se_session *sess = cmd->se_sess;
 206         struct se_node_acl *nacl;
 207         struct se_ua *ua = NULL, *ua_p;
 208         int head = 1;
 209
 210         if (!sess)
 211                 return;
 212
 213         nacl = sess->se_node_acl;
 214         if (!nacl)
 215                 return;
 216
 217         spin_lock_irq(&nacl->device_list_lock);
 218         deve = nacl->device_list[cmd->orig_fe_lun];
 219         if (!atomic_read(&deve->ua_count)) {
 220                 spin_unlock_irq(&nacl->device_list_lock);
 221                 return;
 222         }
 223         /*
 224          * The highest priority Unit Attentions are placed at the head of the
 225          * struct se_dev_entry->ua_list, and will be returned in CHECK_CONDITION +
 226          * sense data for the received CDB.
 227          */
 228         spin_lock(&deve->ua_lock);
 229         list_for_each_entry_safe(ua, ua_p, &deve->ua_list, ua_nacl_list) {
 230                 /*
 231                  * For ua_intlck_ctrl code not equal to 00b, only report the
 232                  * highest priority UNIT_ATTENTION and ASC/ASCQ without
 233                  * clearing it.
 234                  */
 235                 if (dev->dev_attrib.emulate_ua_intlck_ctrl != 0) {
 236                         *asc = ua->ua_asc;
 237                         *ascq = ua->ua_ascq;
 238                         break;
 239                 }
 240                 /*
 241                  * Otherwise for the default 00b, release the UNIT ATTENTION
 242                  * condition.  Return the ASC/ASCQ of the highest priority UA
 243                  * (head of the list) in the outgoing CHECK_CONDITION + sense.
 244                  */
 245                 if (head) {
 246                         *asc = ua->ua_asc;
 247                         *ascq = ua->ua_ascq;
 248                         head = 0;
 249                 }
 250                 list_del(&ua->ua_nacl_list);
 251                 kmem_cache_free(se_ua_cache, ua);
 252
 253                 atomic_dec(&deve->ua_count);
 254                 smp_mb__after_atomic_dec();
 255         }
 256         spin_unlock(&deve->ua_lock);
 257         spin_unlock_irq(&nacl->device_list_lock);
 258
 259         pr_debug("[%s]: %s UNIT ATTENTION condition with"
 260                 " INTLCK_CTRL: %d, mapped LUN: %u, got CDB: 0x%02x"
 261                 " reported ASC: 0x%02x, ASCQ: 0x%02x\n",
 262                 nacl->se_tpg->se_tpg_tfo->get_fabric_name(),
 263                 (dev->dev_attrib.emulate_ua_intlck_ctrl != 0) ? "Reporting" :
 264                 "Releasing", dev->dev_attrib.emulate_ua_intlck_ctrl,
 265                 cmd->orig_fe_lun, cmd->t_task_cdb[0], *asc, *ascq);
 266 }
 267
 268 int core_scsi3_ua_clear_for_request_sense(
 269         struct se_cmd *cmd,
 270         u8 *asc,
 271         u8 *ascq)
 272 {
 273         struct se_dev_entry *deve;
 274         struct se_session *sess = cmd->se_sess;
 275         struct se_node_acl *nacl;
 276         struct se_ua *ua = NULL, *ua_p;
 277         int head = 1;
 278
 279         if (!sess)
 280                 return -EINVAL;
 281
 282         nacl = sess->se_node_acl;
 283         if (!nacl)
 284                 return -EINVAL;
 285
 286         spin_lock_irq(&nacl->device_list_lock);
 287         deve = nacl->device_list[cmd->orig_fe_lun];
 288         if (!atomic_read(&deve->ua_count)) {
 289                 spin_unlock_irq(&nacl->device_list_lock);
 290                 return -EPERM;
 291         }
 292         /*
 293          * The highest priority Unit Attentions are placed at the head of the
 294          * struct se_dev_entry->ua_list.  The First (and hence highest priority)
 295          * ASC/ASCQ will be returned in REQUEST_SENSE payload data for the
 296          * matching struct se_lun.
 297          *
 298          * Once the returning ASC/ASCQ values are set, we go ahead and
 299          * release all of the Unit Attention conditions for the associated
 300          * struct se_lun.
 301          */
 302         spin_lock(&deve->ua_lock);
 303         list_for_each_entry_safe(ua, ua_p, &deve->ua_list, ua_nacl_list) {
 304                 if (head) {
 305                         *asc = ua->ua_asc;
 306                         *ascq = ua->ua_ascq;
 307                         head = 0;
 308                 }
 309                 list_del(&ua->ua_nacl_list);
 310                 kmem_cache_free(se_ua_cache, ua);
 311
 312                 atomic_dec(&deve->ua_count);
 313                 smp_mb__after_atomic_dec();
 314         }
 315         spin_unlock(&deve->ua_lock);
 316         spin_unlock_irq(&nacl->device_list_lock);
 317
 318         pr_debug("[%s]: Released UNIT ATTENTION condition, mapped"
 319                 " LUN: %u, got REQUEST_SENSE reported ASC: 0x%02x,"
 320                 " ASCQ: 0x%02x\n", nacl->se_tpg->se_tpg_tfo->get_fabric_name(),
 321                 cmd->orig_fe_lun, *asc, *ascq);
 322
 323         return (head) ? -EPERM : 0;
 324 }