LXR linux/drivers/target/target_core

   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
  38sense_reason_t
  39target_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
  88int 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
 171void 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
 190void 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
 205void 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
 278int 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}
 338