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 (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
  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                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
 169void 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
 188void 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 */
 206bool 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
 277int 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}
 335