LXR linux/drivers/target/target_core

   1// SPDX-License-Identifier: GPL-2.0-or-later
   2/*******************************************************************************
   3 * Filename: target_core_ua.c
   4 *
   5 * This file contains logic for SPC-3 Unit Attention emulation
   6 *
   7 * (c) Copyright 2009-2013 Datera, Inc.
   8 *
   9 * Nicholas A. Bellinger <nab@kernel.org>
  10 *
  11 ******************************************************************************/
  12
  13#include <linux/slab.h>
  14#include <linux/spinlock.h>
  15#include <scsi/scsi_proto.h>
  16
  17#include <target/target_core_base.h>
  18#include <target/target_core_fabric.h>
  19
  20#include "target_core_internal.h"
  21#include "target_core_alua.h"
  22#include "target_core_pr.h"
  23#include "target_core_ua.h"
  24
  25sense_reason_t
  26target_scsi3_ua_check(struct se_cmd *cmd)
  27{
  28        struct se_dev_entry *deve;
  29        struct se_session *sess = cmd->se_sess;
  30        struct se_node_acl *nacl;
  31
  32        if (!sess)
  33                return 0;
  34
  35        nacl = sess->se_node_acl;
  36        if (!nacl)
  37                return 0;
  38
  39        rcu_read_lock();
  40        deve = target_nacl_find_deve(nacl, cmd->orig_fe_lun);
  41        if (!deve) {
  42                rcu_read_unlock();
  43                return 0;
  44        }
  45        if (list_empty_careful(&deve->ua_list)) {
  46                rcu_read_unlock();
  47                return 0;
  48        }
  49        rcu_read_unlock();
  50        /*
  51         * From sam4r14, section 5.14 Unit attention condition:
  52         *
  53         * a) if an INQUIRY command enters the enabled command state, the
  54         *    device server shall process the INQUIRY command and shall neither
  55         *    report nor clear any unit attention condition;
  56         * b) if a REPORT LUNS command enters the enabled command state, the
  57         *    device server shall process the REPORT LUNS command and shall not
  58         *    report any unit attention condition;
  59         * e) if a REQUEST SENSE command enters the enabled command state while
  60         *    a unit attention condition exists for the SCSI initiator port
  61         *    associated with the I_T nexus on which the REQUEST SENSE command
  62         *    was received, then the device server shall process the command
  63         *    and either:
  64         */
  65        switch (cmd->t_task_cdb[0]) {
  66        case INQUIRY:
  67        case REPORT_LUNS:
  68        case REQUEST_SENSE:
  69                return 0;
  70        default:
  71                return TCM_CHECK_CONDITION_UNIT_ATTENTION;
  72        }
  73}
  74
  75int core_scsi3_ua_allocate(
  76        struct se_dev_entry *deve,
  77        u8 asc,
  78        u8 ascq)
  79{
  80        struct se_ua *ua, *ua_p, *ua_tmp;
  81
  82        ua = kmem_cache_zalloc(se_ua_cache, GFP_ATOMIC);
  83        if (!ua) {
  84                pr_err("Unable to allocate struct se_ua\n");
  85                return -ENOMEM;
  86        }
  87        INIT_LIST_HEAD(&ua->ua_nacl_list);
  88
  89        ua->ua_asc = asc;
  90        ua->ua_ascq = ascq;
  91
  92        spin_lock(&deve->ua_lock);
  93        list_for_each_entry_safe(ua_p, ua_tmp, &deve->ua_list, ua_nacl_list) {
  94                /*
  95                 * Do not report the same UNIT ATTENTION twice..
  96                 */
  97                if ((ua_p->ua_asc == asc) && (ua_p->ua_ascq == ascq)) {
  98                        spin_unlock(&deve->ua_lock);
  99                        kmem_cache_free(se_ua_cache, ua);
 100                        return 0;
 101                }
 102                /*
 103                 * Attach the highest priority Unit Attention to
 104                 * the head of the list following sam4r14,
 105                 * Section 5.14 Unit Attention Condition:
 106                 *
 107                 * POWER ON, RESET, OR BUS DEVICE RESET OCCURRED highest
 108                 * POWER ON OCCURRED or
 109                 * DEVICE INTERNAL RESET
 110                 * SCSI BUS RESET OCCURRED or
 111                 * MICROCODE HAS BEEN CHANGED or
 112                 * protocol specific
 113                 * BUS DEVICE RESET FUNCTION OCCURRED
 114                 * I_T NEXUS LOSS OCCURRED
 115                 * COMMANDS CLEARED BY POWER LOSS NOTIFICATION
 116                 * all others                                    Lowest
 117                 *
 118                 * Each of the ASCQ codes listed above are defined in
 119                 * the 29h ASC family, see spc4r17 Table D.1
 120                 */
 121                if (ua_p->ua_asc == 0x29) {
 122                        if ((asc == 0x29) && (ascq > ua_p->ua_ascq))
 123                                list_add(&ua->ua_nacl_list,
 124                                                &deve->ua_list);
 125                        else
 126                                list_add_tail(&ua->ua_nacl_list,
 127                                                &deve->ua_list);
 128                } else if (ua_p->ua_asc == 0x2a) {
 129                        /*
 130                         * Incoming Family 29h ASCQ codes will override
 131                         * Family 2AHh ASCQ codes for Unit Attention condition.
 132                         */
 133                        if ((asc == 0x29) || (ascq > ua_p->ua_asc))
 134                                list_add(&ua->ua_nacl_list,
 135                                        &deve->ua_list);
 136                        else
 137                                list_add_tail(&ua->ua_nacl_list,
 138                                                &deve->ua_list);
 139                } else
 140                        list_add_tail(&ua->ua_nacl_list,
 141                                &deve->ua_list);
 142                spin_unlock(&deve->ua_lock);
 143
 144                return 0;
 145        }
 146        list_add_tail(&ua->ua_nacl_list, &deve->ua_list);
 147        spin_unlock(&deve->ua_lock);
 148
 149        pr_debug("Allocated UNIT ATTENTION, mapped LUN: %llu, ASC:"
 150                " 0x%02x, ASCQ: 0x%02x\n", deve->mapped_lun,
 151                asc, ascq);
 152
 153        return 0;
 154}
 155
 156void target_ua_allocate_lun(struct se_node_acl *nacl,
 157                            u32 unpacked_lun, u8 asc, u8 ascq)
 158{
 159        struct se_dev_entry *deve;
 160
 161        if (!nacl)
 162                return;
 163
 164        rcu_read_lock();
 165        deve = target_nacl_find_deve(nacl, unpacked_lun);
 166        if (!deve) {
 167                rcu_read_unlock();
 168                return;
 169        }
 170
 171        core_scsi3_ua_allocate(deve, asc, ascq);
 172        rcu_read_unlock();
 173}
 174
 175void core_scsi3_ua_release_all(
 176        struct se_dev_entry *deve)
 177{
 178        struct se_ua *ua, *ua_p;
 179
 180        spin_lock(&deve->ua_lock);
 181        list_for_each_entry_safe(ua, ua_p, &deve->ua_list, ua_nacl_list) {
 182                list_del(&ua->ua_nacl_list);
 183                kmem_cache_free(se_ua_cache, ua);
 184        }
 185        spin_unlock(&deve->ua_lock);
 186}
 187
 188/*
 189 * Dequeue a unit attention from the unit attention list. This function
 190 * returns true if the dequeuing succeeded and if *@key, *@asc and *@ascq have
 191 * been set.
 192 */
 193bool core_scsi3_ua_for_check_condition(struct se_cmd *cmd, u8 *key, u8 *asc,
 194                                       u8 *ascq)
 195{
 196        struct se_device *dev = cmd->se_dev;
 197        struct se_dev_entry *deve;
 198        struct se_session *sess = cmd->se_sess;
 199        struct se_node_acl *nacl;
 200        struct se_ua *ua = NULL, *ua_p;
 201        int head = 1;
 202
 203        if (WARN_ON_ONCE(!sess))
 204                return false;
 205
 206        nacl = sess->se_node_acl;
 207        if (WARN_ON_ONCE(!nacl))
 208                return false;
 209
 210        rcu_read_lock();
 211        deve = target_nacl_find_deve(nacl, cmd->orig_fe_lun);
 212        if (!deve) {
 213                rcu_read_unlock();
 214                *key = ILLEGAL_REQUEST;
 215                *asc = 0x25; /* LOGICAL UNIT NOT SUPPORTED */
 216                *ascq = 0;
 217                return true;
 218        }
 219        *key = UNIT_ATTENTION;
 220        /*
 221         * The highest priority Unit Attentions are placed at the head of the
 222         * struct se_dev_entry->ua_list, and will be returned in CHECK_CONDITION +
 223         * sense data for the received CDB.
 224         */
 225        spin_lock(&deve->ua_lock);
 226        list_for_each_entry_safe(ua, ua_p, &deve->ua_list, ua_nacl_list) {
 227                /*
 228                 * For ua_intlck_ctrl code not equal to 00b, only report the
 229                 * highest priority UNIT_ATTENTION and ASC/ASCQ without
 230                 * clearing it.
 231                 */
 232                if (dev->dev_attrib.emulate_ua_intlck_ctrl != 0) {
 233                        *asc = ua->ua_asc;
 234                        *ascq = ua->ua_ascq;
 235                        break;
 236                }
 237                /*
 238                 * Otherwise for the default 00b, release the UNIT ATTENTION
 239                 * condition.  Return the ASC/ASCQ of the highest priority UA
 240                 * (head of the list) in the outgoing CHECK_CONDITION + sense.
 241                 */
 242                if (head) {
 243                        *asc = ua->ua_asc;
 244                        *ascq = ua->ua_ascq;
 245                        head = 0;
 246                }
 247                list_del(&ua->ua_nacl_list);
 248                kmem_cache_free(se_ua_cache, ua);
 249        }
 250        spin_unlock(&deve->ua_lock);
 251        rcu_read_unlock();
 252
 253        pr_debug("[%s]: %s UNIT ATTENTION condition with"
 254                " INTLCK_CTRL: %d, mapped LUN: %llu, got CDB: 0x%02x"
 255                " reported ASC: 0x%02x, ASCQ: 0x%02x\n",
 256                nacl->se_tpg->se_tpg_tfo->fabric_name,
 257                (dev->dev_attrib.emulate_ua_intlck_ctrl != 0) ? "Reporting" :
 258                "Releasing", dev->dev_attrib.emulate_ua_intlck_ctrl,
 259                cmd->orig_fe_lun, cmd->t_task_cdb[0], *asc, *ascq);
 260
 261        return head == 0;
 262}
 263
 264int core_scsi3_ua_clear_for_request_sense(
 265        struct se_cmd *cmd,
 266        u8 *asc,
 267        u8 *ascq)
 268{
 269        struct se_dev_entry *deve;
 270        struct se_session *sess = cmd->se_sess;
 271        struct se_node_acl *nacl;
 272        struct se_ua *ua = NULL, *ua_p;
 273        int head = 1;
 274
 275        if (!sess)
 276                return -EINVAL;
 277
 278        nacl = sess->se_node_acl;
 279        if (!nacl)
 280                return -EINVAL;
 281
 282        rcu_read_lock();
 283        deve = target_nacl_find_deve(nacl, cmd->orig_fe_lun);
 284        if (!deve) {
 285                rcu_read_unlock();
 286                return -EINVAL;
 287        }
 288        if (list_empty_careful(&deve->ua_list)) {
 289                rcu_read_unlock();
 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        spin_unlock(&deve->ua_lock);
 313        rcu_read_unlock();
 314
 315        pr_debug("[%s]: Released UNIT ATTENTION condition, mapped"
 316                " LUN: %llu, got REQUEST_SENSE reported ASC: 0x%02x,"
 317                " ASCQ: 0x%02x\n", nacl->se_tpg->se_tpg_tfo->fabric_name,
 318                cmd->orig_fe_lun, *asc, *ascq);
 319
 320        return (head) ? -EPERM : 0;
 321}
 322