target_core_ua.c

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/*******************************************************************************
 * Filename: target_core_ua.c
 *
 * This file contains logic for SPC-3 Unit Attention emulation
 *
 * Copyright (c) 2009,2010 Rising Tide Systems
 * Copyright (c) 2009,2010 Linux-iSCSI.org
 *
 * Nicholas A. Bellinger <[email protected]>
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation; either version 2 of the License, or
 * (at your option) any later version.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program; if not, write to the Free Software
 * Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
 *
 ******************************************************************************/

#include <linux/slab.h>
#include <linux/spinlock.h>
#include <scsi/scsi.h>
#include <scsi/scsi_cmnd.h>

#include <target/target_core_base.h>
#include <target/target_core_fabric.h>
#include <target/target_core_configfs.h>

#include "target_core_internal.h"
#include "target_core_alua.h"
#include "target_core_pr.h"
#include "target_core_ua.h"

int core_scsi3_ua_check(
    struct se_cmd *cmd,
    unsigned char *cdb)
{
    struct se_dev_entry *deve;
    struct se_session *sess = cmd->se_sess;
    struct se_node_acl *nacl;

    if (!sess)
        return 0;

    nacl = sess->se_node_acl;
    if (!nacl)
        return 0;

    deve = nacl->device_list[cmd->orig_fe_lun];
    if (!atomic_read(&deve->ua_count))
        return 0;
    /*
     * From sam4r14, section 5.14 Unit attention condition:
     *
     * a) if an INQUIRY command enters the enabled command state, the
     *    device server shall process the INQUIRY command and shall neither
     *    report nor clear any unit attention condition;
     * b) if a REPORT LUNS command enters the enabled command state, the
     *    device server shall process the REPORT LUNS command and shall not
     *    report any unit attention condition;
     * e) if a REQUEST SENSE command enters the enabled command state while
     *    a unit attention condition exists for the SCSI initiator port
     *    associated with the I_T nexus on which the REQUEST SENSE command
     *    was received, then the device server shall process the command
     *    and either:
     */
    switch (cdb[0]) {
    case INQUIRY:
    case REPORT_LUNS:
    case REQUEST_SENSE:
        return 0;
    default:
        return -EINVAL;
    }

    return -EINVAL;
}

int core_scsi3_ua_allocate(
    struct se_node_acl *nacl,
    u32 unpacked_lun,
    u8 asc,
    u8 ascq)
{
    struct se_dev_entry *deve;
    struct se_ua *ua, *ua_p, *ua_tmp;
    /*
     * PASSTHROUGH OPS
     */
    if (!nacl)
        return -EINVAL;

    ua = kmem_cache_zalloc(se_ua_cache, GFP_ATOMIC);
    if (!ua) {
        pr_err("Unable to allocate struct se_ua\n");
        return -ENOMEM;
    }
    INIT_LIST_HEAD(&ua->ua_dev_list);
    INIT_LIST_HEAD(&ua->ua_nacl_list);

    ua->ua_nacl = nacl;
    ua->ua_asc = asc;
    ua->ua_ascq = ascq;

    spin_lock_irq(&nacl->device_list_lock);
    deve = nacl->device_list[unpacked_lun];

    spin_lock(&deve->ua_lock);
    list_for_each_entry_safe(ua_p, ua_tmp, &deve->ua_list, ua_nacl_list) {
        /*
         * Do not report the same UNIT ATTENTION twice..
         */
        if ((ua_p->ua_asc == asc) && (ua_p->ua_ascq == ascq)) {
            spin_unlock(&deve->ua_lock);
            spin_unlock_irq(&nacl->device_list_lock);
            kmem_cache_free(se_ua_cache, ua);
            return 0;
        }
        /*
         * Attach the highest priority Unit Attention to
         * the head of the list following sam4r14,
         * Section 5.14 Unit Attention Condition:
         *
         * POWER ON, RESET, OR BUS DEVICE RESET OCCURRED highest
         * POWER ON OCCURRED or
         * DEVICE INTERNAL RESET
         * SCSI BUS RESET OCCURRED or
         * MICROCODE HAS BEEN CHANGED or
         * protocol specific
         * BUS DEVICE RESET FUNCTION OCCURRED
         * I_T NEXUS LOSS OCCURRED
         * COMMANDS CLEARED BY POWER LOSS NOTIFICATION
         * all others                                    Lowest
         *
         * Each of the ASCQ codes listed above are defined in
         * the 29h ASC family, see spc4r17 Table D.1
         */
        if (ua_p->ua_asc == 0x29) {
            if ((asc == 0x29) && (ascq > ua_p->ua_ascq))
                list_add(&ua->ua_nacl_list,
                        &deve->ua_list);
            else
                list_add_tail(&ua->ua_nacl_list,
                        &deve->ua_list);
        } else if (ua_p->ua_asc == 0x2a) {
            /*
             * Incoming Family 29h ASCQ codes will override
             * Family 2AHh ASCQ codes for Unit Attention condition.
             */
            if ((asc == 0x29) || (ascq > ua_p->ua_asc))
                list_add(&ua->ua_nacl_list,
                    &deve->ua_list);
            else
                list_add_tail(&ua->ua_nacl_list,
                        &deve->ua_list);
        } else
            list_add_tail(&ua->ua_nacl_list,
                &deve->ua_list);
        spin_unlock(&deve->ua_lock);
        spin_unlock_irq(&nacl->device_list_lock);

        atomic_inc(&deve->ua_count);
        smp_mb__after_atomic_inc();
        return 0;
    }
    list_add_tail(&ua->ua_nacl_list, &deve->ua_list);
    spin_unlock(&deve->ua_lock);
    spin_unlock_irq(&nacl->device_list_lock);

    pr_debug("[%s]: Allocated UNIT ATTENTION, mapped LUN: %u, ASC:"
        " 0x%02x, ASCQ: 0x%02x\n",
        nacl->se_tpg->se_tpg_tfo->get_fabric_name(), unpacked_lun,
        asc, ascq);

    atomic_inc(&deve->ua_count);
    smp_mb__after_atomic_inc();
    return 0;
}

void core_scsi3_ua_release_all(
    struct se_dev_entry *deve)
{
    struct se_ua *ua, *ua_p;

    spin_lock(&deve->ua_lock);
    list_for_each_entry_safe(ua, ua_p, &deve->ua_list, ua_nacl_list) {
        list_del(&ua->ua_nacl_list);
        kmem_cache_free(se_ua_cache, ua);

        atomic_dec(&deve->ua_count);
        smp_mb__after_atomic_dec();
    }
    spin_unlock(&deve->ua_lock);
}

void core_scsi3_ua_for_check_condition(
    struct se_cmd *cmd,
    u8 *asc,
    u8 *ascq)
{
    struct se_device *dev = cmd->se_dev;
    struct se_dev_entry *deve;
    struct se_session *sess = cmd->se_sess;
    struct se_node_acl *nacl;
    struct se_ua *ua = NULL, *ua_p;
    int head = 1;

    if (!sess)
        return;

    nacl = sess->se_node_acl;
    if (!nacl)
        return;

    spin_lock_irq(&nacl->device_list_lock);
    deve = nacl->device_list[cmd->orig_fe_lun];
    if (!atomic_read(&deve->ua_count)) {
        spin_unlock_irq(&nacl->device_list_lock);
        return;
    }
    /*
     * The highest priority Unit Attentions are placed at the head of the
     * struct se_dev_entry->ua_list, and will be returned in CHECK_CONDITION +
     * sense data for the received CDB.
     */
    spin_lock(&deve->ua_lock);
    list_for_each_entry_safe(ua, ua_p, &deve->ua_list, ua_nacl_list) {
        /*
         * For ua_intlck_ctrl code not equal to 00b, only report the
         * highest priority UNIT_ATTENTION and ASC/ASCQ without
         * clearing it.
         */
        if (dev->se_sub_dev->se_dev_attrib.emulate_ua_intlck_ctrl != 0) {
            *asc = ua->ua_asc;
            *ascq = ua->ua_ascq;
            break;
        }
        /*
         * Otherwise for the default 00b, release the UNIT ATTENTION
         * condition.  Return the ASC/ASCQ of the highest priority UA
         * (head of the list) in the outgoing CHECK_CONDITION + sense.
         */
        if (head) {
            *asc = ua->ua_asc;
            *ascq = ua->ua_ascq;
            head = 0;
        }
        list_del(&ua->ua_nacl_list);
        kmem_cache_free(se_ua_cache, ua);

        atomic_dec(&deve->ua_count);
        smp_mb__after_atomic_dec();
    }
    spin_unlock(&deve->ua_lock);
    spin_unlock_irq(&nacl->device_list_lock);

    pr_debug("[%s]: %s UNIT ATTENTION condition with"
        " INTLCK_CTRL: %d, mapped LUN: %u, got CDB: 0x%02x"
        " reported ASC: 0x%02x, ASCQ: 0x%02x\n",
        nacl->se_tpg->se_tpg_tfo->get_fabric_name(),
        (dev->se_sub_dev->se_dev_attrib.emulate_ua_intlck_ctrl != 0) ? "Reporting" :
        "Releasing", dev->se_sub_dev->se_dev_attrib.emulate_ua_intlck_ctrl,
        cmd->orig_fe_lun, cmd->t_task_cdb[0], *asc, *ascq);
}

int core_scsi3_ua_clear_for_request_sense(
    struct se_cmd *cmd,
    u8 *asc,
    u8 *ascq)
{
    struct se_dev_entry *deve;
    struct se_session *sess = cmd->se_sess;
    struct se_node_acl *nacl;
    struct se_ua *ua = NULL, *ua_p;
    int head = 1;

    if (!sess)
        return -EINVAL;

    nacl = sess->se_node_acl;
    if (!nacl)
        return -EINVAL;

    spin_lock_irq(&nacl->device_list_lock);
    deve = nacl->device_list[cmd->orig_fe_lun];
    if (!atomic_read(&deve->ua_count)) {
        spin_unlock_irq(&nacl->device_list_lock);
        return -EPERM;
    }
    /*
     * The highest priority Unit Attentions are placed at the head of the
     * struct se_dev_entry->ua_list.  The First (and hence highest priority)
     * ASC/ASCQ will be returned in REQUEST_SENSE payload data for the
     * matching struct se_lun.
     *
     * Once the returning ASC/ASCQ values are set, we go ahead and
     * release all of the Unit Attention conditions for the associated
     * struct se_lun.
     */
    spin_lock(&deve->ua_lock);
    list_for_each_entry_safe(ua, ua_p, &deve->ua_list, ua_nacl_list) {
        if (head) {
            *asc = ua->ua_asc;
            *ascq = ua->ua_ascq;
            head = 0;
        }
        list_del(&ua->ua_nacl_list);
        kmem_cache_free(se_ua_cache, ua);

        atomic_dec(&deve->ua_count);
        smp_mb__after_atomic_dec();
    }
    spin_unlock(&deve->ua_lock);
    spin_unlock_irq(&nacl->device_list_lock);

    pr_debug("[%s]: Released UNIT ATTENTION condition, mapped"
        " LUN: %u, got REQUEST_SENSE reported ASC: 0x%02x,"
        " ASCQ: 0x%02x\n", nacl->se_tpg->se_tpg_tfo->get_fabric_name(),
        cmd->orig_fe_lun, *asc, *ascq);

    return (head) ? -EPERM : 0;
}