ocfs2: fix possible use-after-free with AIO

[linux/fpc-iii.git] / drivers / scsi / scsi_transport_iscsi.c

/*
 * iSCSI transport class definitions
 *
 * Copyright (C) IBM Corporation, 2004
 * Copyright (C) Mike Christie, 2004 - 2005
 * Copyright (C) Dmitry Yusupov, 2004 - 2005
 * Copyright (C) Alex Aizman, 2004 - 2005
 *
 * 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/module.h>
#include <linux/mutex.h>
#include <linux/slab.h>
#include <linux/bsg-lib.h>
#include <linux/idr.h>
#include <net/tcp.h>
#include <scsi/scsi.h>
#include <scsi/scsi_host.h>
#include <scsi/scsi_device.h>
#include <scsi/scsi_transport.h>
#include <scsi/scsi_transport_iscsi.h>
#include <scsi/iscsi_if.h>
#include <scsi/scsi_cmnd.h>
#include <scsi/scsi_bsg_iscsi.h>

#define ISCSI_TRANSPORT_VERSION "2.0-870"

static int dbg_session;
module_param_named(debug_session, dbg_session, int,
                   S_IRUGO | S_IWUSR);
MODULE_PARM_DESC(debug_session,
                 "Turn on debugging for sessions in scsi_transport_iscsi "
                 "module. Set to 1 to turn on, and zero to turn off. Default "
                 "is off.");

static int dbg_conn;
module_param_named(debug_conn, dbg_conn, int,
                   S_IRUGO | S_IWUSR);
MODULE_PARM_DESC(debug_conn,
                 "Turn on debugging for connections in scsi_transport_iscsi "
                 "module. Set to 1 to turn on, and zero to turn off. Default "
                 "is off.");

#define ISCSI_DBG_TRANS_SESSION(_session, dbg_fmt, arg...)              \
        do {                                                            \
                if (dbg_session)                                        \
                        iscsi_cls_session_printk(KERN_INFO, _session,   \
                                                 "%s: " dbg_fmt,        \
                                                 __func__, ##arg);      \
        } while (0);

#define ISCSI_DBG_TRANS_CONN(_conn, dbg_fmt, arg...)                    \
        do {                                                            \
                if (dbg_conn)                                           \
                        iscsi_cls_conn_printk(KERN_INFO, _conn,         \
                                              "%s: " dbg_fmt,           \
                                              __func__, ##arg); \
        } while (0);

struct iscsi_internal {
        struct scsi_transport_template t;
        struct iscsi_transport *iscsi_transport;
        struct list_head list;
        struct device dev;

        struct transport_container conn_cont;
        struct transport_container session_cont;
};

static atomic_t iscsi_session_nr; /* sysfs session id for next new session */
static struct workqueue_struct *iscsi_eh_timer_workq;

static DEFINE_IDA(iscsi_sess_ida);
/*
 * list of registered transports and lock that must
 * be held while accessing list. The iscsi_transport_lock must
 * be acquired after the rx_queue_mutex.
 */
static LIST_HEAD(iscsi_transports);
static DEFINE_SPINLOCK(iscsi_transport_lock);

#define to_iscsi_internal(tmpl) \
        container_of(tmpl, struct iscsi_internal, t)

#define dev_to_iscsi_internal(_dev) \
        container_of(_dev, struct iscsi_internal, dev)

static void iscsi_transport_release(struct device *dev)
{
        struct iscsi_internal *priv = dev_to_iscsi_internal(dev);
        kfree(priv);
}

/*
 * iscsi_transport_class represents the iscsi_transports that are
 * registered.
 */
static struct class iscsi_transport_class = {
        .name = "iscsi_transport",
        .dev_release = iscsi_transport_release,
};

static ssize_t
show_transport_handle(struct device *dev, struct device_attribute *attr,
                      char *buf)
{
        struct iscsi_internal *priv = dev_to_iscsi_internal(dev);
        return sprintf(buf, "%llu\n", (unsigned long long)iscsi_handle(priv->iscsi_transport));
}
static DEVICE_ATTR(handle, S_IRUGO, show_transport_handle, NULL);

#define show_transport_attr(name, format)                               \
static ssize_t                                                          \
show_transport_##name(struct device *dev,                               \
                      struct device_attribute *attr,char *buf)          \
{                                                                       \
        struct iscsi_internal *priv = dev_to_iscsi_internal(dev);       \
        return sprintf(buf, format"\n", priv->iscsi_transport->name);   \
}                                                                       \
static DEVICE_ATTR(name, S_IRUGO, show_transport_##name, NULL);

show_transport_attr(caps, "0x%x");

static struct attribute *iscsi_transport_attrs[] = {
        &dev_attr_handle.attr,
        &dev_attr_caps.attr,
        NULL,
};

static struct attribute_group iscsi_transport_group = {
        .attrs = iscsi_transport_attrs,
};

/*
 * iSCSI endpoint attrs
 */
#define iscsi_dev_to_endpoint(_dev) \
        container_of(_dev, struct iscsi_endpoint, dev)

#define ISCSI_ATTR(_prefix,_name,_mode,_show,_store)    \
struct device_attribute dev_attr_##_prefix##_##_name =  \
        __ATTR(_name,_mode,_show,_store)

static void iscsi_endpoint_release(struct device *dev)
{
        struct iscsi_endpoint *ep = iscsi_dev_to_endpoint(dev);
        kfree(ep);
}

static struct class iscsi_endpoint_class = {
        .name = "iscsi_endpoint",
        .dev_release = iscsi_endpoint_release,
};

static ssize_t
show_ep_handle(struct device *dev, struct device_attribute *attr, char *buf)
{
        struct iscsi_endpoint *ep = iscsi_dev_to_endpoint(dev);
        return sprintf(buf, "%llu\n", (unsigned long long) ep->id);
}
static ISCSI_ATTR(ep, handle, S_IRUGO, show_ep_handle, NULL);

static struct attribute *iscsi_endpoint_attrs[] = {
        &dev_attr_ep_handle.attr,
        NULL,
};

static struct attribute_group iscsi_endpoint_group = {
        .attrs = iscsi_endpoint_attrs,
};

#define ISCSI_MAX_EPID -1

static int iscsi_match_epid(struct device *dev, void *data)
{
        struct iscsi_endpoint *ep = iscsi_dev_to_endpoint(dev);
        uint64_t *epid = (uint64_t *) data;

        return *epid == ep->id;
}

struct iscsi_endpoint *
iscsi_create_endpoint(int dd_size)
{
        struct device *dev;
        struct iscsi_endpoint *ep;
        uint64_t id;
        int err;

        for (id = 1; id < ISCSI_MAX_EPID; id++) {
                dev = class_find_device(&iscsi_endpoint_class, NULL, &id,
                                        iscsi_match_epid);
                if (!dev)
                        break;
        }
        if (id == ISCSI_MAX_EPID) {
                printk(KERN_ERR "Too many connections. Max supported %u\n",
                       ISCSI_MAX_EPID - 1);
                return NULL;
        }

        ep = kzalloc(sizeof(*ep) + dd_size, GFP_KERNEL);
        if (!ep)
                return NULL;

        ep->id = id;
        ep->dev.class = &iscsi_endpoint_class;
        dev_set_name(&ep->dev, "ep-%llu", (unsigned long long) id);
        err = device_register(&ep->dev);
        if (err)
                goto free_ep;

        err = sysfs_create_group(&ep->dev.kobj, &iscsi_endpoint_group);
        if (err)
                goto unregister_dev;

        if (dd_size)
                ep->dd_data = &ep[1];
        return ep;

unregister_dev:
        device_unregister(&ep->dev);
        return NULL;

free_ep:
        kfree(ep);
        return NULL;
}
EXPORT_SYMBOL_GPL(iscsi_create_endpoint);

void iscsi_destroy_endpoint(struct iscsi_endpoint *ep)
{
        sysfs_remove_group(&ep->dev.kobj, &iscsi_endpoint_group);
        device_unregister(&ep->dev);
}
EXPORT_SYMBOL_GPL(iscsi_destroy_endpoint);

struct iscsi_endpoint *iscsi_lookup_endpoint(u64 handle)
{
        struct iscsi_endpoint *ep;
        struct device *dev;

        dev = class_find_device(&iscsi_endpoint_class, NULL, &handle,
                                iscsi_match_epid);
        if (!dev)
                return NULL;

        ep = iscsi_dev_to_endpoint(dev);
        /*
         * we can drop this now because the interface will prevent
         * removals and lookups from racing.
         */
        put_device(dev);
        return ep;
}
EXPORT_SYMBOL_GPL(iscsi_lookup_endpoint);

/*
 * Interface to display network param to sysfs
 */

static void iscsi_iface_release(struct device *dev)
{
        struct iscsi_iface *iface = iscsi_dev_to_iface(dev);
        struct device *parent = iface->dev.parent;

        kfree(iface);
        put_device(parent);
}


static struct class iscsi_iface_class = {
        .name = "iscsi_iface",
        .dev_release = iscsi_iface_release,
};

#define ISCSI_IFACE_ATTR(_prefix, _name, _mode, _show, _store)  \
struct device_attribute dev_attr_##_prefix##_##_name =          \
        __ATTR(_name, _mode, _show, _store)

/* iface attrs show */
#define iscsi_iface_attr_show(type, name, param_type, param)            \
static ssize_t                                                          \
show_##type##_##name(struct device *dev, struct device_attribute *attr, \
                     char *buf)                                         \
{                                                                       \
        struct iscsi_iface *iface = iscsi_dev_to_iface(dev);            \
        struct iscsi_transport *t = iface->transport;                   \
        return t->get_iface_param(iface, param_type, param, buf);       \
}                                                                       \

#define iscsi_iface_net_attr(type, name, param)                         \
        iscsi_iface_attr_show(type, name, ISCSI_NET_PARAM, param)       \
static ISCSI_IFACE_ATTR(type, name, S_IRUGO, show_##type##_##name, NULL);

/* generic read only ipvi4 attribute */
iscsi_iface_net_attr(ipv4_iface, ipaddress, ISCSI_NET_PARAM_IPV4_ADDR);
iscsi_iface_net_attr(ipv4_iface, gateway, ISCSI_NET_PARAM_IPV4_GW);
iscsi_iface_net_attr(ipv4_iface, subnet, ISCSI_NET_PARAM_IPV4_SUBNET);
iscsi_iface_net_attr(ipv4_iface, bootproto, ISCSI_NET_PARAM_IPV4_BOOTPROTO);

/* generic read only ipv6 attribute */
iscsi_iface_net_attr(ipv6_iface, ipaddress, ISCSI_NET_PARAM_IPV6_ADDR);
iscsi_iface_net_attr(ipv6_iface, link_local_addr, ISCSI_NET_PARAM_IPV6_LINKLOCAL);
iscsi_iface_net_attr(ipv6_iface, router_addr, ISCSI_NET_PARAM_IPV6_ROUTER);
iscsi_iface_net_attr(ipv6_iface, ipaddr_autocfg,
                     ISCSI_NET_PARAM_IPV6_ADDR_AUTOCFG);
iscsi_iface_net_attr(ipv6_iface, link_local_autocfg,
                     ISCSI_NET_PARAM_IPV6_LINKLOCAL_AUTOCFG);

/* common read only iface attribute */
iscsi_iface_net_attr(iface, enabled, ISCSI_NET_PARAM_IFACE_ENABLE);
iscsi_iface_net_attr(iface, vlan_id, ISCSI_NET_PARAM_VLAN_ID);
iscsi_iface_net_attr(iface, vlan_priority, ISCSI_NET_PARAM_VLAN_PRIORITY);
iscsi_iface_net_attr(iface, vlan_enabled, ISCSI_NET_PARAM_VLAN_ENABLED);
iscsi_iface_net_attr(iface, mtu, ISCSI_NET_PARAM_MTU);
iscsi_iface_net_attr(iface, port, ISCSI_NET_PARAM_PORT);

static mode_t iscsi_iface_attr_is_visible(struct kobject *kobj,
                                          struct attribute *attr, int i)
{
        struct device *dev = container_of(kobj, struct device, kobj);
        struct iscsi_iface *iface = iscsi_dev_to_iface(dev);
        struct iscsi_transport *t = iface->transport;
        int param;

        if (attr == &dev_attr_iface_enabled.attr)
                param = ISCSI_NET_PARAM_IFACE_ENABLE;
        else if (attr == &dev_attr_iface_vlan_id.attr)
                param = ISCSI_NET_PARAM_VLAN_ID;
        else if (attr == &dev_attr_iface_vlan_priority.attr)
                param = ISCSI_NET_PARAM_VLAN_PRIORITY;
        else if (attr == &dev_attr_iface_vlan_enabled.attr)
                param = ISCSI_NET_PARAM_VLAN_ENABLED;
        else if (attr == &dev_attr_iface_mtu.attr)
                param = ISCSI_NET_PARAM_MTU;
        else if (attr == &dev_attr_iface_port.attr)
                param = ISCSI_NET_PARAM_PORT;
        else if (iface->iface_type == ISCSI_IFACE_TYPE_IPV4) {
                if (attr == &dev_attr_ipv4_iface_ipaddress.attr)
                        param = ISCSI_NET_PARAM_IPV4_ADDR;
                else if (attr == &dev_attr_ipv4_iface_gateway.attr)
                        param = ISCSI_NET_PARAM_IPV4_GW;
                else if (attr == &dev_attr_ipv4_iface_subnet.attr)
                        param = ISCSI_NET_PARAM_IPV4_SUBNET;
                else if (attr == &dev_attr_ipv4_iface_bootproto.attr)
                        param = ISCSI_NET_PARAM_IPV4_BOOTPROTO;
                else
                        return 0;
        } else if (iface->iface_type == ISCSI_IFACE_TYPE_IPV6) {
                if (attr == &dev_attr_ipv6_iface_ipaddress.attr)
                        param = ISCSI_NET_PARAM_IPV6_ADDR;
                else if (attr == &dev_attr_ipv6_iface_link_local_addr.attr)
                        param = ISCSI_NET_PARAM_IPV6_LINKLOCAL;
                else if (attr == &dev_attr_ipv6_iface_router_addr.attr)
                        param = ISCSI_NET_PARAM_IPV6_ROUTER;
                else if (attr == &dev_attr_ipv6_iface_ipaddr_autocfg.attr)
                        param = ISCSI_NET_PARAM_IPV6_ADDR_AUTOCFG;
                else if (attr == &dev_attr_ipv6_iface_link_local_autocfg.attr)
                        param = ISCSI_NET_PARAM_IPV6_LINKLOCAL_AUTOCFG;
                else
                        return 0;
        } else {
                WARN_ONCE(1, "Invalid iface attr");
                return 0;
        }

        return t->attr_is_visible(ISCSI_NET_PARAM, param);
}

static struct attribute *iscsi_iface_attrs[] = {
        &dev_attr_iface_enabled.attr,
        &dev_attr_iface_vlan_id.attr,
        &dev_attr_iface_vlan_priority.attr,
        &dev_attr_iface_vlan_enabled.attr,
        &dev_attr_ipv4_iface_ipaddress.attr,
        &dev_attr_ipv4_iface_gateway.attr,
        &dev_attr_ipv4_iface_subnet.attr,
        &dev_attr_ipv4_iface_bootproto.attr,
        &dev_attr_ipv6_iface_ipaddress.attr,
        &dev_attr_ipv6_iface_link_local_addr.attr,
        &dev_attr_ipv6_iface_router_addr.attr,
        &dev_attr_ipv6_iface_ipaddr_autocfg.attr,
        &dev_attr_ipv6_iface_link_local_autocfg.attr,
        &dev_attr_iface_mtu.attr,
        &dev_attr_iface_port.attr,
        NULL,
};

static struct attribute_group iscsi_iface_group = {
        .attrs = iscsi_iface_attrs,
        .is_visible = iscsi_iface_attr_is_visible,
};

struct iscsi_iface *
iscsi_create_iface(struct Scsi_Host *shost, struct iscsi_transport *transport,
                   uint32_t iface_type, uint32_t iface_num, int dd_size)
{
        struct iscsi_iface *iface;
        int err;

        iface = kzalloc(sizeof(*iface) + dd_size, GFP_KERNEL);
        if (!iface)
                return NULL;

        iface->transport = transport;
        iface->iface_type = iface_type;
        iface->iface_num = iface_num;
        iface->dev.release = iscsi_iface_release;
        iface->dev.class = &iscsi_iface_class;
        /* parent reference released in iscsi_iface_release */
        iface->dev.parent = get_device(&shost->shost_gendev);
        if (iface_type == ISCSI_IFACE_TYPE_IPV4)
                dev_set_name(&iface->dev, "ipv4-iface-%u-%u", shost->host_no,
                             iface_num);
        else
                dev_set_name(&iface->dev, "ipv6-iface-%u-%u", shost->host_no,
                             iface_num);

        err = device_register(&iface->dev);
        if (err)
                goto free_iface;

        err = sysfs_create_group(&iface->dev.kobj, &iscsi_iface_group);
        if (err)
                goto unreg_iface;

        if (dd_size)
                iface->dd_data = &iface[1];
        return iface;

unreg_iface:
        device_unregister(&iface->dev);
        return NULL;

free_iface:
        put_device(iface->dev.parent);
        kfree(iface);
        return NULL;
}
EXPORT_SYMBOL_GPL(iscsi_create_iface);

void iscsi_destroy_iface(struct iscsi_iface *iface)
{
        sysfs_remove_group(&iface->dev.kobj, &iscsi_iface_group);
        device_unregister(&iface->dev);
}
EXPORT_SYMBOL_GPL(iscsi_destroy_iface);

/*
 * BSG support
 */
/**
 * iscsi_bsg_host_dispatch - Dispatch command to LLD.
 * @job: bsg job to be processed
 */
static int iscsi_bsg_host_dispatch(struct bsg_job *job)
{
        struct Scsi_Host *shost = iscsi_job_to_shost(job);
        struct iscsi_bsg_request *req = job->request;
        struct iscsi_bsg_reply *reply = job->reply;
        struct iscsi_internal *i = to_iscsi_internal(shost->transportt);
        int cmdlen = sizeof(uint32_t);  /* start with length of msgcode */
        int ret;

        /* check if we have the msgcode value at least */
        if (job->request_len < sizeof(uint32_t)) {
                ret = -ENOMSG;
                goto fail_host_msg;
        }

        /* Validate the host command */
        switch (req->msgcode) {
        case ISCSI_BSG_HST_VENDOR:
                cmdlen += sizeof(struct iscsi_bsg_host_vendor);
                if ((shost->hostt->vendor_id == 0L) ||
                    (req->rqst_data.h_vendor.vendor_id !=
                        shost->hostt->vendor_id)) {
                        ret = -ESRCH;
                        goto fail_host_msg;
                }
                break;
        default:
                ret = -EBADR;
                goto fail_host_msg;
        }

        /* check if we really have all the request data needed */
        if (job->request_len < cmdlen) {
                ret = -ENOMSG;
                goto fail_host_msg;
        }

        ret = i->iscsi_transport->bsg_request(job);
        if (!ret)
                return 0;

fail_host_msg:
        /* return the errno failure code as the only status */
        BUG_ON(job->reply_len < sizeof(uint32_t));
        reply->reply_payload_rcv_len = 0;
        reply->result = ret;
        job->reply_len = sizeof(uint32_t);
        bsg_job_done(job, ret, 0);
        return 0;
}

/**
 * iscsi_bsg_host_add - Create and add the bsg hooks to receive requests
 * @shost: shost for iscsi_host
 * @ihost: iscsi_cls_host adding the structures to
 */
static int
iscsi_bsg_host_add(struct Scsi_Host *shost, struct iscsi_cls_host *ihost)
{
        struct device *dev = &shost->shost_gendev;
        struct iscsi_internal *i = to_iscsi_internal(shost->transportt);
        struct request_queue *q;
        char bsg_name[20];
        int ret;

        if (!i->iscsi_transport->bsg_request)
                return -ENOTSUPP;

        snprintf(bsg_name, sizeof(bsg_name), "iscsi_host%d", shost->host_no);

        q = __scsi_alloc_queue(shost, bsg_request_fn);
        if (!q)
                return -ENOMEM;

        ret = bsg_setup_queue(dev, q, bsg_name, iscsi_bsg_host_dispatch, 0);
        if (ret) {
                shost_printk(KERN_ERR, shost, "bsg interface failed to "
                             "initialize - no request queue\n");
                blk_cleanup_queue(q);
                return ret;
        }

        ihost->bsg_q = q;
        return 0;
}

static int iscsi_setup_host(struct transport_container *tc, struct device *dev,
                            struct device *cdev)
{
        struct Scsi_Host *shost = dev_to_shost(dev);
        struct iscsi_cls_host *ihost = shost->shost_data;

        memset(ihost, 0, sizeof(*ihost));
        atomic_set(&ihost->nr_scans, 0);
        mutex_init(&ihost->mutex);

        iscsi_bsg_host_add(shost, ihost);
        /* ignore any bsg add error - we just can't do sgio */

        return 0;
}

static int iscsi_remove_host(struct transport_container *tc,
                             struct device *dev, struct device *cdev)
{
        struct Scsi_Host *shost = dev_to_shost(dev);
        struct iscsi_cls_host *ihost = shost->shost_data;

        if (ihost->bsg_q) {
                bsg_remove_queue(ihost->bsg_q);
                blk_cleanup_queue(ihost->bsg_q);
        }
        return 0;
}

static DECLARE_TRANSPORT_CLASS(iscsi_host_class,
                               "iscsi_host",
                               iscsi_setup_host,
                               iscsi_remove_host,
                               NULL);

static DECLARE_TRANSPORT_CLASS(iscsi_session_class,
                               "iscsi_session",
                               NULL,
                               NULL,
                               NULL);

static DECLARE_TRANSPORT_CLASS(iscsi_connection_class,
                               "iscsi_connection",
                               NULL,
                               NULL,
                               NULL);

static struct sock *nls;
static DEFINE_MUTEX(rx_queue_mutex);

static LIST_HEAD(sesslist);
static DEFINE_SPINLOCK(sesslock);
static LIST_HEAD(connlist);
static DEFINE_SPINLOCK(connlock);

static uint32_t iscsi_conn_get_sid(struct iscsi_cls_conn *conn)
{
        struct iscsi_cls_session *sess = iscsi_dev_to_session(conn->dev.parent);
        return sess->sid;
}

/*
 * Returns the matching session to a given sid
 */
static struct iscsi_cls_session *iscsi_session_lookup(uint32_t sid)
{
        unsigned long flags;
        struct iscsi_cls_session *sess;

        spin_lock_irqsave(&sesslock, flags);
        list_for_each_entry(sess, &sesslist, sess_list) {
                if (sess->sid == sid) {
                        spin_unlock_irqrestore(&sesslock, flags);
                        return sess;
                }
        }
        spin_unlock_irqrestore(&sesslock, flags);
        return NULL;
}

/*
 * Returns the matching connection to a given sid / cid tuple
 */
static struct iscsi_cls_conn *iscsi_conn_lookup(uint32_t sid, uint32_t cid)
{
        unsigned long flags;
        struct iscsi_cls_conn *conn;

        spin_lock_irqsave(&connlock, flags);
        list_for_each_entry(conn, &connlist, conn_list) {
                if ((conn->cid == cid) && (iscsi_conn_get_sid(conn) == sid)) {
                        spin_unlock_irqrestore(&connlock, flags);
                        return conn;
                }
        }
        spin_unlock_irqrestore(&connlock, flags);
        return NULL;
}

/*
 * The following functions can be used by LLDs that allocate
 * their own scsi_hosts or by software iscsi LLDs
 */
static struct {
        int value;
        char *name;
} iscsi_session_state_names[] = {
        { ISCSI_SESSION_LOGGED_IN,      "LOGGED_IN" },
        { ISCSI_SESSION_FAILED,         "FAILED" },
        { ISCSI_SESSION_FREE,           "FREE" },
};

static const char *iscsi_session_state_name(int state)
{
        int i;
        char *name = NULL;

        for (i = 0; i < ARRAY_SIZE(iscsi_session_state_names); i++) {
                if (iscsi_session_state_names[i].value == state) {
                        name = iscsi_session_state_names[i].name;
                        break;
                }
        }
        return name;
}

int iscsi_session_chkready(struct iscsi_cls_session *session)
{
        unsigned long flags;
        int err;

        spin_lock_irqsave(&session->lock, flags);
        switch (session->state) {
        case ISCSI_SESSION_LOGGED_IN:
                err = 0;
                break;
        case ISCSI_SESSION_FAILED:
                err = DID_IMM_RETRY << 16;
                break;
        case ISCSI_SESSION_FREE:
                err = DID_TRANSPORT_FAILFAST << 16;
                break;
        default:
                err = DID_NO_CONNECT << 16;
                break;
        }
        spin_unlock_irqrestore(&session->lock, flags);
        return err;
}
EXPORT_SYMBOL_GPL(iscsi_session_chkready);

int iscsi_is_session_online(struct iscsi_cls_session *session)
{
        unsigned long flags;
        int ret = 0;

        spin_lock_irqsave(&session->lock, flags);
        if (session->state == ISCSI_SESSION_LOGGED_IN)
                ret = 1;
        spin_unlock_irqrestore(&session->lock, flags);
        return ret;
}
EXPORT_SYMBOL_GPL(iscsi_is_session_online);

static void iscsi_session_release(struct device *dev)
{
        struct iscsi_cls_session *session = iscsi_dev_to_session(dev);
        struct Scsi_Host *shost;

        shost = iscsi_session_to_shost(session);
        scsi_host_put(shost);
        ISCSI_DBG_TRANS_SESSION(session, "Completing session release\n");
        kfree(session);
}

static int iscsi_is_session_dev(const struct device *dev)
{
        return dev->release == iscsi_session_release;
}

static int iscsi_iter_session_fn(struct device *dev, void *data)
{
        void (* fn) (struct iscsi_cls_session *) = data;

        if (!iscsi_is_session_dev(dev))
                return 0;
        fn(iscsi_dev_to_session(dev));
        return 0;
}

void iscsi_host_for_each_session(struct Scsi_Host *shost,
                                 void (*fn)(struct iscsi_cls_session *))
{
        device_for_each_child(&shost->shost_gendev, fn,
                              iscsi_iter_session_fn);
}
EXPORT_SYMBOL_GPL(iscsi_host_for_each_session);

/**
 * iscsi_scan_finished - helper to report when running scans are done
 * @shost: scsi host
 * @time: scan run time
 *
 * This function can be used by drives like qla4xxx to report to the scsi
 * layer when the scans it kicked off at module load time are done.
 */
int iscsi_scan_finished(struct Scsi_Host *shost, unsigned long time)
{
        struct iscsi_cls_host *ihost = shost->shost_data;
        /*
         * qla4xxx will have kicked off some session unblocks before calling
         * scsi_scan_host, so just wait for them to complete.
         */
        return !atomic_read(&ihost->nr_scans);
}
EXPORT_SYMBOL_GPL(iscsi_scan_finished);

struct iscsi_scan_data {
        unsigned int channel;
        unsigned int id;
        unsigned int lun;
};

static int iscsi_user_scan_session(struct device *dev, void *data)
{
        struct iscsi_scan_data *scan_data = data;
        struct iscsi_cls_session *session;
        struct Scsi_Host *shost;
        struct iscsi_cls_host *ihost;
        unsigned long flags;
        unsigned int id;

        if (!iscsi_is_session_dev(dev))
                return 0;

        session = iscsi_dev_to_session(dev);

        ISCSI_DBG_TRANS_SESSION(session, "Scanning session\n");

        shost = iscsi_session_to_shost(session);
        ihost = shost->shost_data;

        mutex_lock(&ihost->mutex);
        spin_lock_irqsave(&session->lock, flags);
        if (session->state != ISCSI_SESSION_LOGGED_IN) {
                spin_unlock_irqrestore(&session->lock, flags);
                goto user_scan_exit;
        }
        id = session->target_id;
        spin_unlock_irqrestore(&session->lock, flags);

        if (id != ISCSI_MAX_TARGET) {
                if ((scan_data->channel == SCAN_WILD_CARD ||
                     scan_data->channel == 0) &&
                    (scan_data->id == SCAN_WILD_CARD ||
                     scan_data->id == id))
                        scsi_scan_target(&session->dev, 0, id,
                                         scan_data->lun, 1);
        }

user_scan_exit:
        mutex_unlock(&ihost->mutex);
        ISCSI_DBG_TRANS_SESSION(session, "Completed session scan\n");
        return 0;
}

static int iscsi_user_scan(struct Scsi_Host *shost, uint channel,
                           uint id, uint lun)
{
        struct iscsi_scan_data scan_data;

        scan_data.channel = channel;
        scan_data.id = id;
        scan_data.lun = lun;

        return device_for_each_child(&shost->shost_gendev, &scan_data,
                                     iscsi_user_scan_session);
}

static void iscsi_scan_session(struct work_struct *work)
{
        struct iscsi_cls_session *session =
                        container_of(work, struct iscsi_cls_session, scan_work);
        struct Scsi_Host *shost = iscsi_session_to_shost(session);
        struct iscsi_cls_host *ihost = shost->shost_data;
        struct iscsi_scan_data scan_data;

        scan_data.channel = 0;
        scan_data.id = SCAN_WILD_CARD;
        scan_data.lun = SCAN_WILD_CARD;

        iscsi_user_scan_session(&session->dev, &scan_data);
        atomic_dec(&ihost->nr_scans);
}

/**
 * iscsi_block_scsi_eh - block scsi eh until session state has transistioned
 * @cmd: scsi cmd passed to scsi eh handler
 *
 * If the session is down this function will wait for the recovery
 * timer to fire or for the session to be logged back in. If the
 * recovery timer fires then FAST_IO_FAIL is returned. The caller
 * should pass this error value to the scsi eh.
 */
int iscsi_block_scsi_eh(struct scsi_cmnd *cmd)
{
        struct iscsi_cls_session *session =
                        starget_to_session(scsi_target(cmd->device));
        unsigned long flags;
        int ret = 0;

        spin_lock_irqsave(&session->lock, flags);
        while (session->state != ISCSI_SESSION_LOGGED_IN) {
                if (session->state == ISCSI_SESSION_FREE) {
                        ret = FAST_IO_FAIL;
                        break;
                }
                spin_unlock_irqrestore(&session->lock, flags);
                msleep(1000);
                spin_lock_irqsave(&session->lock, flags);
        }
        spin_unlock_irqrestore(&session->lock, flags);
        return ret;
}
EXPORT_SYMBOL_GPL(iscsi_block_scsi_eh);

static void session_recovery_timedout(struct work_struct *work)
{
        struct iscsi_cls_session *session =
                container_of(work, struct iscsi_cls_session,
                             recovery_work.work);
        unsigned long flags;

        iscsi_cls_session_printk(KERN_INFO, session,
                                 "session recovery timed out after %d secs\n",
                                 session->recovery_tmo);

        spin_lock_irqsave(&session->lock, flags);
        switch (session->state) {
        case ISCSI_SESSION_FAILED:
                session->state = ISCSI_SESSION_FREE;
                break;
        case ISCSI_SESSION_LOGGED_IN:
        case ISCSI_SESSION_FREE:
                /* we raced with the unblock's flush */
                spin_unlock_irqrestore(&session->lock, flags);
                return;
        }
        spin_unlock_irqrestore(&session->lock, flags);

        if (session->transport->session_recovery_timedout)
                session->transport->session_recovery_timedout(session);

        ISCSI_DBG_TRANS_SESSION(session, "Unblocking SCSI target\n");
        scsi_target_unblock(&session->dev);
        ISCSI_DBG_TRANS_SESSION(session, "Completed unblocking SCSI target\n");
}

static void __iscsi_unblock_session(struct work_struct *work)
{
        struct iscsi_cls_session *session =
                        container_of(work, struct iscsi_cls_session,
                                     unblock_work);
        struct Scsi_Host *shost = iscsi_session_to_shost(session);
        struct iscsi_cls_host *ihost = shost->shost_data;
        unsigned long flags;

        ISCSI_DBG_TRANS_SESSION(session, "Unblocking session\n");
        /*
         * The recovery and unblock work get run from the same workqueue,
         * so try to cancel it if it was going to run after this unblock.
         */
        cancel_delayed_work(&session->recovery_work);
        spin_lock_irqsave(&session->lock, flags);
        session->state = ISCSI_SESSION_LOGGED_IN;
        spin_unlock_irqrestore(&session->lock, flags);
        /* start IO */
        scsi_target_unblock(&session->dev);
        /*
         * Only do kernel scanning if the driver is properly hooked into
         * the async scanning code (drivers like iscsi_tcp do login and
         * scanning from userspace).
         */
        if (shost->hostt->scan_finished) {
                if (scsi_queue_work(shost, &session->scan_work))
                        atomic_inc(&ihost->nr_scans);
        }
        ISCSI_DBG_TRANS_SESSION(session, "Completed unblocking session\n");
}

/**
 * iscsi_unblock_session - set a session as logged in and start IO.
 * @session: iscsi session
 *
 * Mark a session as ready to accept IO.
 */
void iscsi_unblock_session(struct iscsi_cls_session *session)
{
        queue_work(iscsi_eh_timer_workq, &session->unblock_work);
        /*
         * make sure all the events have completed before tell the driver
         * it is safe
         */
        flush_workqueue(iscsi_eh_timer_workq);
}
EXPORT_SYMBOL_GPL(iscsi_unblock_session);

static void __iscsi_block_session(struct work_struct *work)
{
        struct iscsi_cls_session *session =
                        container_of(work, struct iscsi_cls_session,
                                     block_work);
        unsigned long flags;

        ISCSI_DBG_TRANS_SESSION(session, "Blocking session\n");
        spin_lock_irqsave(&session->lock, flags);
        session->state = ISCSI_SESSION_FAILED;
        spin_unlock_irqrestore(&session->lock, flags);
        scsi_target_block(&session->dev);
        ISCSI_DBG_TRANS_SESSION(session, "Completed SCSI target blocking\n");
        if (session->recovery_tmo >= 0)
                queue_delayed_work(iscsi_eh_timer_workq,
                                   &session->recovery_work,
                                   session->recovery_tmo * HZ);
}

void iscsi_block_session(struct iscsi_cls_session *session)
{
        queue_work(iscsi_eh_timer_workq, &session->block_work);
}
EXPORT_SYMBOL_GPL(iscsi_block_session);

static void __iscsi_unbind_session(struct work_struct *work)
{
        struct iscsi_cls_session *session =
                        container_of(work, struct iscsi_cls_session,
                                     unbind_work);
        struct Scsi_Host *shost = iscsi_session_to_shost(session);
        struct iscsi_cls_host *ihost = shost->shost_data;
        unsigned long flags;
        unsigned int target_id;

        ISCSI_DBG_TRANS_SESSION(session, "Unbinding session\n");

        /* Prevent new scans and make sure scanning is not in progress */
        mutex_lock(&ihost->mutex);
        spin_lock_irqsave(&session->lock, flags);
        if (session->target_id == ISCSI_MAX_TARGET) {
                spin_unlock_irqrestore(&session->lock, flags);
                mutex_unlock(&ihost->mutex);
                return;
        }

        target_id = session->target_id;
        session->target_id = ISCSI_MAX_TARGET;
        spin_unlock_irqrestore(&session->lock, flags);
        mutex_unlock(&ihost->mutex);

        if (session->ida_used)
                ida_simple_remove(&iscsi_sess_ida, target_id);

        scsi_remove_target(&session->dev);
        iscsi_session_event(session, ISCSI_KEVENT_UNBIND_SESSION);
        ISCSI_DBG_TRANS_SESSION(session, "Completed target removal\n");
}

struct iscsi_cls_session *
iscsi_alloc_session(struct Scsi_Host *shost, struct iscsi_transport *transport,
                    int dd_size)
{
        struct iscsi_cls_session *session;

        session = kzalloc(sizeof(*session) + dd_size,
                          GFP_KERNEL);
        if (!session)
                return NULL;

        session->transport = transport;
        session->recovery_tmo = 120;
        session->state = ISCSI_SESSION_FREE;
        INIT_DELAYED_WORK(&session->recovery_work, session_recovery_timedout);
        INIT_LIST_HEAD(&session->sess_list);
        INIT_WORK(&session->unblock_work, __iscsi_unblock_session);
        INIT_WORK(&session->block_work, __iscsi_block_session);
        INIT_WORK(&session->unbind_work, __iscsi_unbind_session);
        INIT_WORK(&session->scan_work, iscsi_scan_session);
        spin_lock_init(&session->lock);

        /* this is released in the dev's release function */
        scsi_host_get(shost);
        session->dev.parent = &shost->shost_gendev;
        session->dev.release = iscsi_session_release;
        device_initialize(&session->dev);
        if (dd_size)
                session->dd_data = &session[1];

        ISCSI_DBG_TRANS_SESSION(session, "Completed session allocation\n");
        return session;
}
EXPORT_SYMBOL_GPL(iscsi_alloc_session);

int iscsi_add_session(struct iscsi_cls_session *session, unsigned int target_id)
{
        struct Scsi_Host *shost = iscsi_session_to_shost(session);
        struct iscsi_cls_host *ihost;
        unsigned long flags;
        int id = 0;
        int err;

        ihost = shost->shost_data;
        session->sid = atomic_add_return(1, &iscsi_session_nr);

        if (target_id == ISCSI_MAX_TARGET) {
                id = ida_simple_get(&iscsi_sess_ida, 0, 0, GFP_KERNEL);

                if (id < 0) {
                        iscsi_cls_session_printk(KERN_ERR, session,
                                        "Failure in Target ID Allocation\n");
                        return id;
                }
                session->target_id = (unsigned int)id;
                session->ida_used = true;
        } else
                session->target_id = target_id;

        dev_set_name(&session->dev, "session%u", session->sid);
        err = device_add(&session->dev);
        if (err) {
                iscsi_cls_session_printk(KERN_ERR, session,
                                         "could not register session's dev\n");
                goto release_ida;
        }
        transport_register_device(&session->dev);

        spin_lock_irqsave(&sesslock, flags);
        list_add(&session->sess_list, &sesslist);
        spin_unlock_irqrestore(&sesslock, flags);

        iscsi_session_event(session, ISCSI_KEVENT_CREATE_SESSION);
        ISCSI_DBG_TRANS_SESSION(session, "Completed session adding\n");
        return 0;

release_ida:
        if (session->ida_used)
                ida_simple_remove(&iscsi_sess_ida, session->target_id);

        return err;
}
EXPORT_SYMBOL_GPL(iscsi_add_session);

/**
 * iscsi_create_session - create iscsi class session
 * @shost: scsi host
 * @transport: iscsi transport
 * @dd_size: private driver data size
 * @target_id: which target
 *
 * This can be called from a LLD or iscsi_transport.
 */
struct iscsi_cls_session *
iscsi_create_session(struct Scsi_Host *shost, struct iscsi_transport *transport,
                     int dd_size, unsigned int target_id)
{
        struct iscsi_cls_session *session;

        session = iscsi_alloc_session(shost, transport, dd_size);
        if (!session)
                return NULL;

        if (iscsi_add_session(session, target_id)) {
                iscsi_free_session(session);
                return NULL;
        }
        return session;
}
EXPORT_SYMBOL_GPL(iscsi_create_session);

static void iscsi_conn_release(struct device *dev)
{
        struct iscsi_cls_conn *conn = iscsi_dev_to_conn(dev);
        struct device *parent = conn->dev.parent;

        ISCSI_DBG_TRANS_CONN(conn, "Releasing conn\n");
        kfree(conn);
        put_device(parent);
}

static int iscsi_is_conn_dev(const struct device *dev)
{
        return dev->release == iscsi_conn_release;
}

static int iscsi_iter_destroy_conn_fn(struct device *dev, void *data)
{
        if (!iscsi_is_conn_dev(dev))
                return 0;
        return iscsi_destroy_conn(iscsi_dev_to_conn(dev));
}

void iscsi_remove_session(struct iscsi_cls_session *session)
{
        struct Scsi_Host *shost = iscsi_session_to_shost(session);
        unsigned long flags;
        int err;

        ISCSI_DBG_TRANS_SESSION(session, "Removing session\n");

        spin_lock_irqsave(&sesslock, flags);
        list_del(&session->sess_list);
        spin_unlock_irqrestore(&sesslock, flags);

        /* make sure there are no blocks/unblocks queued */
        flush_workqueue(iscsi_eh_timer_workq);
        /* make sure the timedout callout is not running */
        if (!cancel_delayed_work(&session->recovery_work))
                flush_workqueue(iscsi_eh_timer_workq);
        /*
         * If we are blocked let commands flow again. The lld or iscsi
         * layer should set up the queuecommand to fail commands.
         * We assume that LLD will not be calling block/unblock while
         * removing the session.
         */
        spin_lock_irqsave(&session->lock, flags);
        session->state = ISCSI_SESSION_FREE;
        spin_unlock_irqrestore(&session->lock, flags);

        scsi_target_unblock(&session->dev);
        /* flush running scans then delete devices */
        scsi_flush_work(shost);
        __iscsi_unbind_session(&session->unbind_work);

        /* hw iscsi may not have removed all connections from session */
        err = device_for_each_child(&session->dev, NULL,
                                    iscsi_iter_destroy_conn_fn);
        if (err)
                iscsi_cls_session_printk(KERN_ERR, session,
                                         "Could not delete all connections "
                                         "for session. Error %d.\n", err);

        transport_unregister_device(&session->dev);

        ISCSI_DBG_TRANS_SESSION(session, "Completing session removal\n");
        device_del(&session->dev);
}
EXPORT_SYMBOL_GPL(iscsi_remove_session);

void iscsi_free_session(struct iscsi_cls_session *session)
{
        ISCSI_DBG_TRANS_SESSION(session, "Freeing session\n");
        iscsi_session_event(session, ISCSI_KEVENT_DESTROY_SESSION);
        put_device(&session->dev);
}
EXPORT_SYMBOL_GPL(iscsi_free_session);

/**
 * iscsi_destroy_session - destroy iscsi session
 * @session: iscsi_session
 *
 * Can be called by a LLD or iscsi_transport. There must not be
 * any running connections.
 */
int iscsi_destroy_session(struct iscsi_cls_session *session)
{
        iscsi_remove_session(session);
        ISCSI_DBG_TRANS_SESSION(session, "Completing session destruction\n");
        iscsi_free_session(session);
        return 0;
}
EXPORT_SYMBOL_GPL(iscsi_destroy_session);

/**
 * iscsi_create_conn - create iscsi class connection
 * @session: iscsi cls session
 * @dd_size: private driver data size
 * @cid: connection id
 *
 * This can be called from a LLD or iscsi_transport. The connection
 * is child of the session so cid must be unique for all connections
 * on the session.
 *
 * Since we do not support MCS, cid will normally be zero. In some cases
 * for software iscsi we could be trying to preallocate a connection struct
 * in which case there could be two connection structs and cid would be
 * non-zero.
 */
struct iscsi_cls_conn *
iscsi_create_conn(struct iscsi_cls_session *session, int dd_size, uint32_t cid)
{
        struct iscsi_transport *transport = session->transport;
        struct iscsi_cls_conn *conn;
        unsigned long flags;
        int err;

        conn = kzalloc(sizeof(*conn) + dd_size, GFP_KERNEL);
        if (!conn)
                return NULL;
        if (dd_size)
                conn->dd_data = &conn[1];

        mutex_init(&conn->ep_mutex);
        INIT_LIST_HEAD(&conn->conn_list);
        conn->transport = transport;
        conn->cid = cid;

        /* this is released in the dev's release function */
        if (!get_device(&session->dev))
                goto free_conn;

        dev_set_name(&conn->dev, "connection%d:%u", session->sid, cid);
        conn->dev.parent = &session->dev;
        conn->dev.release = iscsi_conn_release;
        err = device_register(&conn->dev);
        if (err) {
                iscsi_cls_session_printk(KERN_ERR, session, "could not "
                                         "register connection's dev\n");
                goto release_parent_ref;
        }
        transport_register_device(&conn->dev);

        spin_lock_irqsave(&connlock, flags);
        list_add(&conn->conn_list, &connlist);
        spin_unlock_irqrestore(&connlock, flags);

        ISCSI_DBG_TRANS_CONN(conn, "Completed conn creation\n");
        return conn;

release_parent_ref:
        put_device(&session->dev);
free_conn:
        kfree(conn);
        return NULL;
}

EXPORT_SYMBOL_GPL(iscsi_create_conn);

/**
 * iscsi_destroy_conn - destroy iscsi class connection
 * @conn: iscsi cls session
 *
 * This can be called from a LLD or iscsi_transport.
 */
int iscsi_destroy_conn(struct iscsi_cls_conn *conn)
{
        unsigned long flags;

        spin_lock_irqsave(&connlock, flags);
        list_del(&conn->conn_list);
        spin_unlock_irqrestore(&connlock, flags);

        transport_unregister_device(&conn->dev);
        ISCSI_DBG_TRANS_CONN(conn, "Completing conn destruction\n");
        device_unregister(&conn->dev);
        return 0;
}
EXPORT_SYMBOL_GPL(iscsi_destroy_conn);

/*
 * iscsi interface functions
 */
static struct iscsi_internal *
iscsi_if_transport_lookup(struct iscsi_transport *tt)
{
        struct iscsi_internal *priv;
        unsigned long flags;

        spin_lock_irqsave(&iscsi_transport_lock, flags);
        list_for_each_entry(priv, &iscsi_transports, list) {
                if (tt == priv->iscsi_transport) {
                        spin_unlock_irqrestore(&iscsi_transport_lock, flags);
                        return priv;
                }
        }
        spin_unlock_irqrestore(&iscsi_transport_lock, flags);
        return NULL;
}

static int
iscsi_multicast_skb(struct sk_buff *skb, uint32_t group, gfp_t gfp)
{
        return nlmsg_multicast(nls, skb, 0, group, gfp);
}

int iscsi_recv_pdu(struct iscsi_cls_conn *conn, struct iscsi_hdr *hdr,
                   char *data, uint32_t data_size)
{
        struct nlmsghdr *nlh;
        struct sk_buff *skb;
        struct iscsi_uevent *ev;
        char *pdu;
        struct iscsi_internal *priv;
        int len = NLMSG_SPACE(sizeof(*ev) + sizeof(struct iscsi_hdr) +
                              data_size);

        priv = iscsi_if_transport_lookup(conn->transport);
        if (!priv)
                return -EINVAL;

        skb = alloc_skb(len, GFP_ATOMIC);
        if (!skb) {
                iscsi_conn_error_event(conn, ISCSI_ERR_CONN_FAILED);
                iscsi_cls_conn_printk(KERN_ERR, conn, "can not deliver "
                                      "control PDU: OOM\n");
                return -ENOMEM;
        }

        nlh = __nlmsg_put(skb, 0, 0, 0, (len - sizeof(*nlh)), 0);
        ev = NLMSG_DATA(nlh);
        memset(ev, 0, sizeof(*ev));
        ev->transport_handle = iscsi_handle(conn->transport);
        ev->type = ISCSI_KEVENT_RECV_PDU;
        ev->r.recv_req.cid = conn->cid;
        ev->r.recv_req.sid = iscsi_conn_get_sid(conn);
        pdu = (char*)ev + sizeof(*ev);
        memcpy(pdu, hdr, sizeof(struct iscsi_hdr));
        memcpy(pdu + sizeof(struct iscsi_hdr), data, data_size);

        return iscsi_multicast_skb(skb, ISCSI_NL_GRP_ISCSID, GFP_ATOMIC);
}
EXPORT_SYMBOL_GPL(iscsi_recv_pdu);

int iscsi_offload_mesg(struct Scsi_Host *shost,
                       struct iscsi_transport *transport, uint32_t type,
                       char *data, uint16_t data_size)
{
        struct nlmsghdr *nlh;
        struct sk_buff *skb;
        struct iscsi_uevent *ev;
        int len = NLMSG_SPACE(sizeof(*ev) + data_size);

        skb = alloc_skb(len, GFP_ATOMIC);
        if (!skb) {
                printk(KERN_ERR "can not deliver iscsi offload message:OOM\n");
                return -ENOMEM;
        }

        nlh = __nlmsg_put(skb, 0, 0, 0, (len - sizeof(*nlh)), 0);
        ev = NLMSG_DATA(nlh);
        memset(ev, 0, sizeof(*ev));
        ev->type = type;
        ev->transport_handle = iscsi_handle(transport);
        switch (type) {
        case ISCSI_KEVENT_PATH_REQ:
                ev->r.req_path.host_no = shost->host_no;
                break;
        case ISCSI_KEVENT_IF_DOWN:
                ev->r.notify_if_down.host_no = shost->host_no;
                break;
        }

        memcpy((char *)ev + sizeof(*ev), data, data_size);

        return iscsi_multicast_skb(skb, ISCSI_NL_GRP_UIP, GFP_ATOMIC);
}
EXPORT_SYMBOL_GPL(iscsi_offload_mesg);

void iscsi_conn_error_event(struct iscsi_cls_conn *conn, enum iscsi_err error)
{
        struct nlmsghdr *nlh;
        struct sk_buff  *skb;
        struct iscsi_uevent *ev;
        struct iscsi_internal *priv;
        int len = NLMSG_SPACE(sizeof(*ev));

        priv = iscsi_if_transport_lookup(conn->transport);
        if (!priv)
                return;

        skb = alloc_skb(len, GFP_ATOMIC);
        if (!skb) {
                iscsi_cls_conn_printk(KERN_ERR, conn, "gracefully ignored "
                                      "conn error (%d)\n", error);
                return;
        }

        nlh = __nlmsg_put(skb, 0, 0, 0, (len - sizeof(*nlh)), 0);
        ev = NLMSG_DATA(nlh);
        ev->transport_handle = iscsi_handle(conn->transport);
        ev->type = ISCSI_KEVENT_CONN_ERROR;
        ev->r.connerror.error = error;
        ev->r.connerror.cid = conn->cid;
        ev->r.connerror.sid = iscsi_conn_get_sid(conn);

        iscsi_multicast_skb(skb, ISCSI_NL_GRP_ISCSID, GFP_ATOMIC);

        iscsi_cls_conn_printk(KERN_INFO, conn, "detected conn error (%d)\n",
                              error);
}
EXPORT_SYMBOL_GPL(iscsi_conn_error_event);

void iscsi_conn_login_event(struct iscsi_cls_conn *conn,
                            enum iscsi_conn_state state)
{
        struct nlmsghdr *nlh;
        struct sk_buff  *skb;
        struct iscsi_uevent *ev;
        struct iscsi_internal *priv;
        int len = NLMSG_SPACE(sizeof(*ev));

        priv = iscsi_if_transport_lookup(conn->transport);
        if (!priv)
                return;

        skb = alloc_skb(len, GFP_ATOMIC);
        if (!skb) {
                iscsi_cls_conn_printk(KERN_ERR, conn, "gracefully ignored "
                                      "conn login (%d)\n", state);
                return;
        }

        nlh = __nlmsg_put(skb, 0, 0, 0, (len - sizeof(*nlh)), 0);
        ev = NLMSG_DATA(nlh);
        ev->transport_handle = iscsi_handle(conn->transport);
        ev->type = ISCSI_KEVENT_CONN_LOGIN_STATE;
        ev->r.conn_login.state = state;
        ev->r.conn_login.cid = conn->cid;
        ev->r.conn_login.sid = iscsi_conn_get_sid(conn);
        iscsi_multicast_skb(skb, ISCSI_NL_GRP_ISCSID, GFP_ATOMIC);

        iscsi_cls_conn_printk(KERN_INFO, conn, "detected conn login (%d)\n",
                              state);
}
EXPORT_SYMBOL_GPL(iscsi_conn_login_event);

static int
iscsi_if_send_reply(uint32_t group, int seq, int type, int done, int multi,
                    void *payload, int size)
{
        struct sk_buff  *skb;
        struct nlmsghdr *nlh;
        int len = NLMSG_SPACE(size);
        int flags = multi ? NLM_F_MULTI : 0;
        int t = done ? NLMSG_DONE : type;

        skb = alloc_skb(len, GFP_ATOMIC);
        if (!skb) {
                printk(KERN_ERR "Could not allocate skb to send reply.\n");
                return -ENOMEM;
        }

        nlh = __nlmsg_put(skb, 0, 0, t, (len - sizeof(*nlh)), 0);
        nlh->nlmsg_flags = flags;
        memcpy(NLMSG_DATA(nlh), payload, size);
        return iscsi_multicast_skb(skb, group, GFP_ATOMIC);
}

static int
iscsi_if_get_stats(struct iscsi_transport *transport, struct nlmsghdr *nlh)
{
        struct iscsi_uevent *ev = NLMSG_DATA(nlh);
        struct iscsi_stats *stats;
        struct sk_buff *skbstat;
        struct iscsi_cls_conn *conn;
        struct nlmsghdr *nlhstat;
        struct iscsi_uevent *evstat;
        struct iscsi_internal *priv;
        int len = NLMSG_SPACE(sizeof(*ev) +
                              sizeof(struct iscsi_stats) +
                              sizeof(struct iscsi_stats_custom) *
                              ISCSI_STATS_CUSTOM_MAX);
        int err = 0;

        priv = iscsi_if_transport_lookup(transport);
        if (!priv)
                return -EINVAL;

        conn = iscsi_conn_lookup(ev->u.get_stats.sid, ev->u.get_stats.cid);
        if (!conn)
                return -EEXIST;

        do {
                int actual_size;

                skbstat = alloc_skb(len, GFP_ATOMIC);
                if (!skbstat) {
                        iscsi_cls_conn_printk(KERN_ERR, conn, "can not "
                                              "deliver stats: OOM\n");
                        return -ENOMEM;
                }

                nlhstat = __nlmsg_put(skbstat, 0, 0, 0,
                                      (len - sizeof(*nlhstat)), 0);
                evstat = NLMSG_DATA(nlhstat);
                memset(evstat, 0, sizeof(*evstat));
                evstat->transport_handle = iscsi_handle(conn->transport);
                evstat->type = nlh->nlmsg_type;
                evstat->u.get_stats.cid =
                        ev->u.get_stats.cid;
                evstat->u.get_stats.sid =
                        ev->u.get_stats.sid;
                stats = (struct iscsi_stats *)
                        ((char*)evstat + sizeof(*evstat));
                memset(stats, 0, sizeof(*stats));

                transport->get_stats(conn, stats);
                actual_size = NLMSG_SPACE(sizeof(struct iscsi_uevent) +
                                          sizeof(struct iscsi_stats) +
                                          sizeof(struct iscsi_stats_custom) *
                                          stats->custom_length);
                actual_size -= sizeof(*nlhstat);
                actual_size = NLMSG_LENGTH(actual_size);
                skb_trim(skbstat, NLMSG_ALIGN(actual_size));
                nlhstat->nlmsg_len = actual_size;

                err = iscsi_multicast_skb(skbstat, ISCSI_NL_GRP_ISCSID,
                                          GFP_ATOMIC);
        } while (err < 0 && err != -ECONNREFUSED);

        return err;
}

/**
 * iscsi_session_event - send session destr. completion event
 * @session: iscsi class session
 * @event: type of event
 */
int iscsi_session_event(struct iscsi_cls_session *session,
                        enum iscsi_uevent_e event)
{
        struct iscsi_internal *priv;
        struct Scsi_Host *shost;
        struct iscsi_uevent *ev;
        struct sk_buff  *skb;
        struct nlmsghdr *nlh;
        int rc, len = NLMSG_SPACE(sizeof(*ev));

        priv = iscsi_if_transport_lookup(session->transport);
        if (!priv)
                return -EINVAL;
        shost = iscsi_session_to_shost(session);

        skb = alloc_skb(len, GFP_KERNEL);
        if (!skb) {
                iscsi_cls_session_printk(KERN_ERR, session,
                                         "Cannot notify userspace of session "
                                         "event %u\n", event);
                return -ENOMEM;
        }

        nlh = __nlmsg_put(skb, 0, 0, 0, (len - sizeof(*nlh)), 0);
        ev = NLMSG_DATA(nlh);
        ev->transport_handle = iscsi_handle(session->transport);

        ev->type = event;
        switch (event) {
        case ISCSI_KEVENT_DESTROY_SESSION:
                ev->r.d_session.host_no = shost->host_no;
                ev->r.d_session.sid = session->sid;
                break;
        case ISCSI_KEVENT_CREATE_SESSION:
                ev->r.c_session_ret.host_no = shost->host_no;
                ev->r.c_session_ret.sid = session->sid;
                break;
        case ISCSI_KEVENT_UNBIND_SESSION:
                ev->r.unbind_session.host_no = shost->host_no;
                ev->r.unbind_session.sid = session->sid;
                break;
        default:
                iscsi_cls_session_printk(KERN_ERR, session, "Invalid event "
                                         "%u.\n", event);
                kfree_skb(skb);
                return -EINVAL;
        }

        /*
         * this will occur if the daemon is not up, so we just warn
         * the user and when the daemon is restarted it will handle it
         */
        rc = iscsi_multicast_skb(skb, ISCSI_NL_GRP_ISCSID, GFP_KERNEL);
        if (rc == -ESRCH)
                iscsi_cls_session_printk(KERN_ERR, session,
                                         "Cannot notify userspace of session "
                                         "event %u. Check iscsi daemon\n",
                                         event);

        ISCSI_DBG_TRANS_SESSION(session, "Completed handling event %d rc %d\n",
                                event, rc);
        return rc;
}
EXPORT_SYMBOL_GPL(iscsi_session_event);

static int
iscsi_if_create_session(struct iscsi_internal *priv, struct iscsi_endpoint *ep,
                        struct iscsi_uevent *ev, uint32_t initial_cmdsn,
                        uint16_t cmds_max, uint16_t queue_depth)
{
        struct iscsi_transport *transport = priv->iscsi_transport;
        struct iscsi_cls_session *session;
        struct Scsi_Host *shost;

        session = transport->create_session(ep, cmds_max, queue_depth,
                                            initial_cmdsn);
        if (!session)
                return -ENOMEM;

        shost = iscsi_session_to_shost(session);
        ev->r.c_session_ret.host_no = shost->host_no;
        ev->r.c_session_ret.sid = session->sid;
        ISCSI_DBG_TRANS_SESSION(session,
                                "Completed creating transport session\n");
        return 0;
}

static int
iscsi_if_create_conn(struct iscsi_transport *transport, struct iscsi_uevent *ev)
{
        struct iscsi_cls_conn *conn;
        struct iscsi_cls_session *session;

        session = iscsi_session_lookup(ev->u.c_conn.sid);
        if (!session) {
                printk(KERN_ERR "iscsi: invalid session %d.\n",
                       ev->u.c_conn.sid);
                return -EINVAL;
        }

        conn = transport->create_conn(session, ev->u.c_conn.cid);
        if (!conn) {
                iscsi_cls_session_printk(KERN_ERR, session,
                                         "couldn't create a new connection.");
                return -ENOMEM;
        }

        ev->r.c_conn_ret.sid = session->sid;
        ev->r.c_conn_ret.cid = conn->cid;

        ISCSI_DBG_TRANS_CONN(conn, "Completed creating transport conn\n");
        return 0;
}

static int
iscsi_if_destroy_conn(struct iscsi_transport *transport, struct iscsi_uevent *ev)
{
        struct iscsi_cls_conn *conn;

        conn = iscsi_conn_lookup(ev->u.d_conn.sid, ev->u.d_conn.cid);
        if (!conn)
                return -EINVAL;

        ISCSI_DBG_TRANS_CONN(conn, "Destroying transport conn\n");
        if (transport->destroy_conn)
                transport->destroy_conn(conn);

        return 0;
}

static int
iscsi_set_param(struct iscsi_transport *transport, struct iscsi_uevent *ev)
{
        char *data = (char*)ev + sizeof(*ev);
        struct iscsi_cls_conn *conn;
        struct iscsi_cls_session *session;
        int err = 0, value = 0;

        session = iscsi_session_lookup(ev->u.set_param.sid);
        conn = iscsi_conn_lookup(ev->u.set_param.sid, ev->u.set_param.cid);
        if (!conn || !session)
                return -EINVAL;

        switch (ev->u.set_param.param) {
        case ISCSI_PARAM_SESS_RECOVERY_TMO:
                sscanf(data, "%d", &value);
                session->recovery_tmo = value;
                break;
        default:
                err = transport->set_param(conn, ev->u.set_param.param,
                                           data, ev->u.set_param.len);
        }

        return err;
}

static int iscsi_if_ep_connect(struct iscsi_transport *transport,
                               struct iscsi_uevent *ev, int msg_type)
{
        struct iscsi_endpoint *ep;
        struct sockaddr *dst_addr;
        struct Scsi_Host *shost = NULL;
        int non_blocking, err = 0;

        if (!transport->ep_connect)
                return -EINVAL;

        if (msg_type == ISCSI_UEVENT_TRANSPORT_EP_CONNECT_THROUGH_HOST) {
                shost = scsi_host_lookup(ev->u.ep_connect_through_host.host_no);
                if (!shost) {
                        printk(KERN_ERR "ep connect failed. Could not find "
                               "host no %u\n",
                               ev->u.ep_connect_through_host.host_no);
                        return -ENODEV;
                }
                non_blocking = ev->u.ep_connect_through_host.non_blocking;
        } else
                non_blocking = ev->u.ep_connect.non_blocking;

        dst_addr = (struct sockaddr *)((char*)ev + sizeof(*ev));
        ep = transport->ep_connect(shost, dst_addr, non_blocking);
        if (IS_ERR(ep)) {
                err = PTR_ERR(ep);
                goto release_host;
        }

        ev->r.ep_connect_ret.handle = ep->id;
release_host:
        if (shost)
                scsi_host_put(shost);
        return err;
}

static int iscsi_if_ep_disconnect(struct iscsi_transport *transport,
                                  u64 ep_handle)
{
        struct iscsi_cls_conn *conn;
        struct iscsi_endpoint *ep;

        if (!transport->ep_disconnect)
                return -EINVAL;

        ep = iscsi_lookup_endpoint(ep_handle);
        if (!ep)
                return -EINVAL;
        conn = ep->conn;
        if (conn) {
                mutex_lock(&conn->ep_mutex);
                conn->ep = NULL;
                mutex_unlock(&conn->ep_mutex);
        }

        transport->ep_disconnect(ep);
        return 0;
}

static int
iscsi_if_transport_ep(struct iscsi_transport *transport,
                      struct iscsi_uevent *ev, int msg_type)
{
        struct iscsi_endpoint *ep;
        int rc = 0;

        switch (msg_type) {
        case ISCSI_UEVENT_TRANSPORT_EP_CONNECT_THROUGH_HOST:
        case ISCSI_UEVENT_TRANSPORT_EP_CONNECT:
                rc = iscsi_if_ep_connect(transport, ev, msg_type);
                break;
        case ISCSI_UEVENT_TRANSPORT_EP_POLL:
                if (!transport->ep_poll)
                        return -EINVAL;

                ep = iscsi_lookup_endpoint(ev->u.ep_poll.ep_handle);
                if (!ep)
                        return -EINVAL;

                ev->r.retcode = transport->ep_poll(ep,
                                                   ev->u.ep_poll.timeout_ms);
                break;
        case ISCSI_UEVENT_TRANSPORT_EP_DISCONNECT:
                rc = iscsi_if_ep_disconnect(transport,
                                            ev->u.ep_disconnect.ep_handle);
                break;
        }
        return rc;
}

static int
iscsi_tgt_dscvr(struct iscsi_transport *transport,
                struct iscsi_uevent *ev)
{
        struct Scsi_Host *shost;
        struct sockaddr *dst_addr;
        int err;

        if (!transport->tgt_dscvr)
                return -EINVAL;

        shost = scsi_host_lookup(ev->u.tgt_dscvr.host_no);
        if (!shost) {
                printk(KERN_ERR "target discovery could not find host no %u\n",
                       ev->u.tgt_dscvr.host_no);
                return -ENODEV;
        }


        dst_addr = (struct sockaddr *)((char*)ev + sizeof(*ev));
        err = transport->tgt_dscvr(shost, ev->u.tgt_dscvr.type,
                                   ev->u.tgt_dscvr.enable, dst_addr);
        scsi_host_put(shost);
        return err;
}

static int
iscsi_set_host_param(struct iscsi_transport *transport,
                     struct iscsi_uevent *ev)
{
        char *data = (char*)ev + sizeof(*ev);
        struct Scsi_Host *shost;
        int err;

        if (!transport->set_host_param)
                return -ENOSYS;

        shost = scsi_host_lookup(ev->u.set_host_param.host_no);
        if (!shost) {
                printk(KERN_ERR "set_host_param could not find host no %u\n",
                       ev->u.set_host_param.host_no);
                return -ENODEV;
        }

        err = transport->set_host_param(shost, ev->u.set_host_param.param,
                                        data, ev->u.set_host_param.len);
        scsi_host_put(shost);
        return err;
}

static int
iscsi_set_path(struct iscsi_transport *transport, struct iscsi_uevent *ev)
{
        struct Scsi_Host *shost;
        struct iscsi_path *params;
        int err;

        if (!transport->set_path)
                return -ENOSYS;

        shost = scsi_host_lookup(ev->u.set_path.host_no);
        if (!shost) {
                printk(KERN_ERR "set path could not find host no %u\n",
                       ev->u.set_path.host_no);
                return -ENODEV;
        }

        params = (struct iscsi_path *)((char *)ev + sizeof(*ev));
        err = transport->set_path(shost, params);

        scsi_host_put(shost);
        return err;
}

static int
iscsi_set_iface_params(struct iscsi_transport *transport,
                       struct iscsi_uevent *ev, uint32_t len)
{
        char *data = (char *)ev + sizeof(*ev);
        struct Scsi_Host *shost;
        int err;

        if (!transport->set_iface_param)
                return -ENOSYS;

        shost = scsi_host_lookup(ev->u.set_iface_params.host_no);
        if (!shost) {
                printk(KERN_ERR "set_iface_params could not find host no %u\n",
                       ev->u.set_iface_params.host_no);
                return -ENODEV;
        }

        err = transport->set_iface_param(shost, data, len);
        scsi_host_put(shost);
        return err;
}

static int
iscsi_if_recv_msg(struct sk_buff *skb, struct nlmsghdr *nlh, uint32_t *group)
{
        int err = 0;
        struct iscsi_uevent *ev = NLMSG_DATA(nlh);
        struct iscsi_transport *transport = NULL;
        struct iscsi_internal *priv;
        struct iscsi_cls_session *session;
        struct iscsi_cls_conn *conn;
        struct iscsi_endpoint *ep = NULL;

        if (nlh->nlmsg_type == ISCSI_UEVENT_PATH_UPDATE)
                *group = ISCSI_NL_GRP_UIP;
        else
                *group = ISCSI_NL_GRP_ISCSID;

        priv = iscsi_if_transport_lookup(iscsi_ptr(ev->transport_handle));
        if (!priv)
                return -EINVAL;
        transport = priv->iscsi_transport;

        if (!try_module_get(transport->owner))
                return -EINVAL;

        switch (nlh->nlmsg_type) {
        case ISCSI_UEVENT_CREATE_SESSION:
                err = iscsi_if_create_session(priv, ep, ev,
                                              ev->u.c_session.initial_cmdsn,
                                              ev->u.c_session.cmds_max,
                                              ev->u.c_session.queue_depth);
                break;
        case ISCSI_UEVENT_CREATE_BOUND_SESSION:
                ep = iscsi_lookup_endpoint(ev->u.c_bound_session.ep_handle);
                if (!ep) {
                        err = -EINVAL;
                        break;
                }

                err = iscsi_if_create_session(priv, ep, ev,
                                        ev->u.c_bound_session.initial_cmdsn,
                                        ev->u.c_bound_session.cmds_max,
                                        ev->u.c_bound_session.queue_depth);
                break;
        case ISCSI_UEVENT_DESTROY_SESSION:
                session = iscsi_session_lookup(ev->u.d_session.sid);
                if (session)
                        transport->destroy_session(session);
                else
                        err = -EINVAL;
                break;
        case ISCSI_UEVENT_UNBIND_SESSION:
                session = iscsi_session_lookup(ev->u.d_session.sid);
                if (session)
                        scsi_queue_work(iscsi_session_to_shost(session),
                                        &session->unbind_work);
                else
                        err = -EINVAL;
                break;
        case ISCSI_UEVENT_CREATE_CONN:
                err = iscsi_if_create_conn(transport, ev);
                break;
        case ISCSI_UEVENT_DESTROY_CONN:
                err = iscsi_if_destroy_conn(transport, ev);
                break;
        case ISCSI_UEVENT_BIND_CONN:
                session = iscsi_session_lookup(ev->u.b_conn.sid);
                conn = iscsi_conn_lookup(ev->u.b_conn.sid, ev->u.b_conn.cid);

                if (conn && conn->ep)
                        iscsi_if_ep_disconnect(transport, conn->ep->id);

                if (!session || !conn) {
                        err = -EINVAL;
                        break;
                }

                ev->r.retcode = transport->bind_conn(session, conn,
                                                ev->u.b_conn.transport_eph,
                                                ev->u.b_conn.is_leading);
                if (ev->r.retcode || !transport->ep_connect)
                        break;

                ep = iscsi_lookup_endpoint(ev->u.b_conn.transport_eph);
                if (ep) {
                        ep->conn = conn;

                        mutex_lock(&conn->ep_mutex);
                        conn->ep = ep;
                        mutex_unlock(&conn->ep_mutex);
                } else
                        iscsi_cls_conn_printk(KERN_ERR, conn,
                                              "Could not set ep conn "
                                              "binding\n");
                break;
        case ISCSI_UEVENT_SET_PARAM:
                err = iscsi_set_param(transport, ev);
                break;
        case ISCSI_UEVENT_START_CONN:
                conn = iscsi_conn_lookup(ev->u.start_conn.sid, ev->u.start_conn.cid);
                if (conn)
                        ev->r.retcode = transport->start_conn(conn);
                else
                        err = -EINVAL;
                break;
        case ISCSI_UEVENT_STOP_CONN:
                conn = iscsi_conn_lookup(ev->u.stop_conn.sid, ev->u.stop_conn.cid);
                if (conn)
                        transport->stop_conn(conn, ev->u.stop_conn.flag);
                else
                        err = -EINVAL;
                break;
        case ISCSI_UEVENT_SEND_PDU:
                conn = iscsi_conn_lookup(ev->u.send_pdu.sid, ev->u.send_pdu.cid);
                if (conn)
                        ev->r.retcode = transport->send_pdu(conn,
                                (struct iscsi_hdr*)((char*)ev + sizeof(*ev)),
                                (char*)ev + sizeof(*ev) + ev->u.send_pdu.hdr_size,
                                ev->u.send_pdu.data_size);
                else
                        err = -EINVAL;
                break;
        case ISCSI_UEVENT_GET_STATS:
                err = iscsi_if_get_stats(transport, nlh);
                break;
        case ISCSI_UEVENT_TRANSPORT_EP_CONNECT:
        case ISCSI_UEVENT_TRANSPORT_EP_POLL:
        case ISCSI_UEVENT_TRANSPORT_EP_DISCONNECT:
        case ISCSI_UEVENT_TRANSPORT_EP_CONNECT_THROUGH_HOST:
                err = iscsi_if_transport_ep(transport, ev, nlh->nlmsg_type);
                break;
        case ISCSI_UEVENT_TGT_DSCVR:
                err = iscsi_tgt_dscvr(transport, ev);
                break;
        case ISCSI_UEVENT_SET_HOST_PARAM:
                err = iscsi_set_host_param(transport, ev);
                break;
        case ISCSI_UEVENT_PATH_UPDATE:
                err = iscsi_set_path(transport, ev);
                break;
        case ISCSI_UEVENT_SET_IFACE_PARAMS:
                err = iscsi_set_iface_params(transport, ev,
                                             nlmsg_attrlen(nlh, sizeof(*ev)));
                break;
        default:
                err = -ENOSYS;
                break;
        }

        module_put(transport->owner);
        return err;
}

/*
 * Get message from skb.  Each message is processed by iscsi_if_recv_msg.
 * Malformed skbs with wrong lengths or invalid creds are not processed.
 */
static void
iscsi_if_rx(struct sk_buff *skb)
{
        mutex_lock(&rx_queue_mutex);
        while (skb->len >= NLMSG_SPACE(0)) {
                int err;
                uint32_t rlen;
                struct nlmsghdr *nlh;
                struct iscsi_uevent *ev;
                uint32_t group;

                nlh = nlmsg_hdr(skb);
                if (nlh->nlmsg_len < sizeof(*nlh) ||
                    skb->len < nlh->nlmsg_len) {
                        break;
                }

                ev = NLMSG_DATA(nlh);
                rlen = NLMSG_ALIGN(nlh->nlmsg_len);
                if (rlen > skb->len)
                        rlen = skb->len;

                err = iscsi_if_recv_msg(skb, nlh, &group);
                if (err) {
                        ev->type = ISCSI_KEVENT_IF_ERROR;
                        ev->iferror = err;
                }
                do {
                        /*
                         * special case for GET_STATS:
                         * on success - sending reply and stats from
                         * inside of if_recv_msg(),
                         * on error - fall through.
                         */
                        if (ev->type == ISCSI_UEVENT_GET_STATS && !err)
                                break;
                        err = iscsi_if_send_reply(group, nlh->nlmsg_seq,
                                nlh->nlmsg_type, 0, 0, ev, sizeof(*ev));
                } while (err < 0 && err != -ECONNREFUSED);
                skb_pull(skb, rlen);
        }
        mutex_unlock(&rx_queue_mutex);
}

#define ISCSI_CLASS_ATTR(_prefix,_name,_mode,_show,_store)              \
struct device_attribute dev_attr_##_prefix##_##_name =  \
        __ATTR(_name,_mode,_show,_store)

/*
 * iSCSI connection attrs
 */
#define iscsi_conn_attr_show(param)                                     \
static ssize_t                                                          \
show_conn_param_##param(struct device *dev,                             \
                        struct device_attribute *attr, char *buf)       \
{                                                                       \
        struct iscsi_cls_conn *conn = iscsi_dev_to_conn(dev->parent);   \
        struct iscsi_transport *t = conn->transport;                    \
        return t->get_conn_param(conn, param, buf);                     \
}

#define iscsi_conn_attr(field, param)                                   \
        iscsi_conn_attr_show(param)                                     \
static ISCSI_CLASS_ATTR(conn, field, S_IRUGO, show_conn_param_##param,  \
                        NULL);

iscsi_conn_attr(max_recv_dlength, ISCSI_PARAM_MAX_RECV_DLENGTH);
iscsi_conn_attr(max_xmit_dlength, ISCSI_PARAM_MAX_XMIT_DLENGTH);
iscsi_conn_attr(header_digest, ISCSI_PARAM_HDRDGST_EN);
iscsi_conn_attr(data_digest, ISCSI_PARAM_DATADGST_EN);
iscsi_conn_attr(ifmarker, ISCSI_PARAM_IFMARKER_EN);
iscsi_conn_attr(ofmarker, ISCSI_PARAM_OFMARKER_EN);
iscsi_conn_attr(persistent_port, ISCSI_PARAM_PERSISTENT_PORT);
iscsi_conn_attr(exp_statsn, ISCSI_PARAM_EXP_STATSN);
iscsi_conn_attr(persistent_address, ISCSI_PARAM_PERSISTENT_ADDRESS);
iscsi_conn_attr(ping_tmo, ISCSI_PARAM_PING_TMO);
iscsi_conn_attr(recv_tmo, ISCSI_PARAM_RECV_TMO);

#define iscsi_conn_ep_attr_show(param)                                  \
static ssize_t show_conn_ep_param_##param(struct device *dev,           \
                                          struct device_attribute *attr,\
                                          char *buf)                    \
{                                                                       \
        struct iscsi_cls_conn *conn = iscsi_dev_to_conn(dev->parent);   \
        struct iscsi_transport *t = conn->transport;                    \
        struct iscsi_endpoint *ep;                                      \
        ssize_t rc;                                                     \
                                                                        \
        /*                                                              \
         * Need to make sure ep_disconnect does not free the LLD's      \
         * interconnect resources while we are trying to read them.     \
         */                                                             \
        mutex_lock(&conn->ep_mutex);                                    \
        ep = conn->ep;                                                  \
        if (!ep && t->ep_connect) {                                     \
                mutex_unlock(&conn->ep_mutex);                          \
                return -ENOTCONN;                                       \
        }                                                               \
                                                                        \
        if (ep)                                                         \
                rc = t->get_ep_param(ep, param, buf);                   \
        else                                                            \
                rc = t->get_conn_param(conn, param, buf);               \
        mutex_unlock(&conn->ep_mutex);                                  \
        return rc;                                                      \
}

#define iscsi_conn_ep_attr(field, param)                                \
        iscsi_conn_ep_attr_show(param)                                  \
static ISCSI_CLASS_ATTR(conn, field, S_IRUGO,                           \
                        show_conn_ep_param_##param, NULL);

iscsi_conn_ep_attr(address, ISCSI_PARAM_CONN_ADDRESS);
iscsi_conn_ep_attr(port, ISCSI_PARAM_CONN_PORT);

static struct attribute *iscsi_conn_attrs[] = {
        &dev_attr_conn_max_recv_dlength.attr,
        &dev_attr_conn_max_xmit_dlength.attr,
        &dev_attr_conn_header_digest.attr,
        &dev_attr_conn_data_digest.attr,
        &dev_attr_conn_ifmarker.attr,
        &dev_attr_conn_ofmarker.attr,
        &dev_attr_conn_address.attr,
        &dev_attr_conn_port.attr,
        &dev_attr_conn_exp_statsn.attr,
        &dev_attr_conn_persistent_address.attr,
        &dev_attr_conn_persistent_port.attr,
        &dev_attr_conn_ping_tmo.attr,
        &dev_attr_conn_recv_tmo.attr,
        NULL,
};

static mode_t iscsi_conn_attr_is_visible(struct kobject *kobj,
                                         struct attribute *attr, int i)
{
        struct device *cdev = container_of(kobj, struct device, kobj);
        struct iscsi_cls_conn *conn = transport_class_to_conn(cdev);
        struct iscsi_transport *t = conn->transport;
        int param;

        if (attr == &dev_attr_conn_max_recv_dlength.attr)
                param = ISCSI_PARAM_MAX_RECV_DLENGTH;
        else if (attr == &dev_attr_conn_max_xmit_dlength.attr)
                param = ISCSI_PARAM_MAX_XMIT_DLENGTH;
        else if (attr == &dev_attr_conn_header_digest.attr)
                param = ISCSI_PARAM_HDRDGST_EN;
        else if (attr == &dev_attr_conn_data_digest.attr)
                param = ISCSI_PARAM_DATADGST_EN;
        else if (attr == &dev_attr_conn_ifmarker.attr)
                param = ISCSI_PARAM_IFMARKER_EN;
        else if (attr == &dev_attr_conn_ofmarker.attr)
                param = ISCSI_PARAM_OFMARKER_EN;
        else if (attr == &dev_attr_conn_address.attr)
                param = ISCSI_PARAM_CONN_ADDRESS;
        else if (attr == &dev_attr_conn_port.attr)
                param = ISCSI_PARAM_CONN_PORT;
        else if (attr == &dev_attr_conn_exp_statsn.attr)
                param = ISCSI_PARAM_EXP_STATSN;
        else if (attr == &dev_attr_conn_persistent_address.attr)
                param = ISCSI_PARAM_PERSISTENT_ADDRESS;
        else if (attr == &dev_attr_conn_persistent_port.attr)
                param = ISCSI_PARAM_PERSISTENT_PORT;
        else if (attr == &dev_attr_conn_ping_tmo.attr)
                param = ISCSI_PARAM_PING_TMO;
        else if (attr == &dev_attr_conn_recv_tmo.attr)
                param = ISCSI_PARAM_RECV_TMO;
        else {
                WARN_ONCE(1, "Invalid conn attr");
                return 0;
        }

        return t->attr_is_visible(ISCSI_PARAM, param);
}

static struct attribute_group iscsi_conn_group = {
        .attrs = iscsi_conn_attrs,
        .is_visible = iscsi_conn_attr_is_visible,
};

/*
 * iSCSI session attrs
 */
#define iscsi_session_attr_show(param, perm)                            \
static ssize_t                                                          \
show_session_param_##param(struct device *dev,                          \
                           struct device_attribute *attr, char *buf)    \
{                                                                       \
        struct iscsi_cls_session *session =                             \
                iscsi_dev_to_session(dev->parent);                      \
        struct iscsi_transport *t = session->transport;                 \
                                                                        \
        if (perm && !capable(CAP_SYS_ADMIN))                            \
                return -EACCES;                                         \
        return t->get_session_param(session, param, buf);               \
}

#define iscsi_session_attr(field, param, perm)                          \
        iscsi_session_attr_show(param, perm)                            \
static ISCSI_CLASS_ATTR(sess, field, S_IRUGO, show_session_param_##param, \
                        NULL);
iscsi_session_attr(targetname, ISCSI_PARAM_TARGET_NAME, 0);
iscsi_session_attr(initial_r2t, ISCSI_PARAM_INITIAL_R2T_EN, 0);
iscsi_session_attr(max_outstanding_r2t, ISCSI_PARAM_MAX_R2T, 0);
iscsi_session_attr(immediate_data, ISCSI_PARAM_IMM_DATA_EN, 0);
iscsi_session_attr(first_burst_len, ISCSI_PARAM_FIRST_BURST, 0);
iscsi_session_attr(max_burst_len, ISCSI_PARAM_MAX_BURST, 0);
iscsi_session_attr(data_pdu_in_order, ISCSI_PARAM_PDU_INORDER_EN, 0);
iscsi_session_attr(data_seq_in_order, ISCSI_PARAM_DATASEQ_INORDER_EN, 0);
iscsi_session_attr(erl, ISCSI_PARAM_ERL, 0);
iscsi_session_attr(tpgt, ISCSI_PARAM_TPGT, 0);
iscsi_session_attr(username, ISCSI_PARAM_USERNAME, 1);
iscsi_session_attr(username_in, ISCSI_PARAM_USERNAME_IN, 1);
iscsi_session_attr(password, ISCSI_PARAM_PASSWORD, 1);
iscsi_session_attr(password_in, ISCSI_PARAM_PASSWORD_IN, 1);
iscsi_session_attr(fast_abort, ISCSI_PARAM_FAST_ABORT, 0);
iscsi_session_attr(abort_tmo, ISCSI_PARAM_ABORT_TMO, 0);
iscsi_session_attr(lu_reset_tmo, ISCSI_PARAM_LU_RESET_TMO, 0);
iscsi_session_attr(tgt_reset_tmo, ISCSI_PARAM_TGT_RESET_TMO, 0);
iscsi_session_attr(ifacename, ISCSI_PARAM_IFACE_NAME, 0);
iscsi_session_attr(initiatorname, ISCSI_PARAM_INITIATOR_NAME, 0);
iscsi_session_attr(targetalias, ISCSI_PARAM_TARGET_ALIAS, 0);

static ssize_t
show_priv_session_state(struct device *dev, struct device_attribute *attr,
                        char *buf)
{
        struct iscsi_cls_session *session = iscsi_dev_to_session(dev->parent);
        return sprintf(buf, "%s\n", iscsi_session_state_name(session->state));
}
static ISCSI_CLASS_ATTR(priv_sess, state, S_IRUGO, show_priv_session_state,
                        NULL);

#define iscsi_priv_session_attr_show(field, format)                     \
static ssize_t                                                          \
show_priv_session_##field(struct device *dev,                           \
                          struct device_attribute *attr, char *buf)     \
{                                                                       \
        struct iscsi_cls_session *session =                             \
                        iscsi_dev_to_session(dev->parent);              \
        if (session->field == -1)                                       \
                return sprintf(buf, "off\n");                           \
        return sprintf(buf, format"\n", session->field);                \
}

#define iscsi_priv_session_attr_store(field)                            \
static ssize_t                                                          \
store_priv_session_##field(struct device *dev,                          \
                           struct device_attribute *attr,               \
                           const char *buf, size_t count)               \
{                                                                       \
        int val;                                                        \
        char *cp;                                                       \
        struct iscsi_cls_session *session =                             \
                iscsi_dev_to_session(dev->parent);                      \
        if ((session->state == ISCSI_SESSION_FREE) ||                   \
            (session->state == ISCSI_SESSION_FAILED))                   \
                return -EBUSY;                                          \
        if (strncmp(buf, "off", 3) == 0)                                \
                session->field = -1;                                    \
        else {                                                          \
                val = simple_strtoul(buf, &cp, 0);                      \
                if (*cp != '\0' && *cp != '\n')                         \
                        return -EINVAL;                                 \
                session->field = val;                                   \
        }                                                               \
        return count;                                                   \
}

#define iscsi_priv_session_rw_attr(field, format)                       \
        iscsi_priv_session_attr_show(field, format)                     \
        iscsi_priv_session_attr_store(field)                            \
static ISCSI_CLASS_ATTR(priv_sess, field, S_IRUGO | S_IWUSR,            \
                        show_priv_session_##field,                      \
                        store_priv_session_##field)
iscsi_priv_session_rw_attr(recovery_tmo, "%d");

static struct attribute *iscsi_session_attrs[] = {
        &dev_attr_sess_initial_r2t.attr,
        &dev_attr_sess_max_outstanding_r2t.attr,
        &dev_attr_sess_immediate_data.attr,
        &dev_attr_sess_first_burst_len.attr,
        &dev_attr_sess_max_burst_len.attr,
        &dev_attr_sess_data_pdu_in_order.attr,
        &dev_attr_sess_data_seq_in_order.attr,
        &dev_attr_sess_erl.attr,
        &dev_attr_sess_targetname.attr,
        &dev_attr_sess_tpgt.attr,
        &dev_attr_sess_password.attr,
        &dev_attr_sess_password_in.attr,
        &dev_attr_sess_username.attr,
        &dev_attr_sess_username_in.attr,
        &dev_attr_sess_fast_abort.attr,
        &dev_attr_sess_abort_tmo.attr,
        &dev_attr_sess_lu_reset_tmo.attr,
        &dev_attr_sess_tgt_reset_tmo.attr,
        &dev_attr_sess_ifacename.attr,
        &dev_attr_sess_initiatorname.attr,
        &dev_attr_sess_targetalias.attr,
        &dev_attr_priv_sess_recovery_tmo.attr,
        &dev_attr_priv_sess_state.attr,
        NULL,
};

static mode_t iscsi_session_attr_is_visible(struct kobject *kobj,
                                            struct attribute *attr, int i)
{
        struct device *cdev = container_of(kobj, struct device, kobj);
        struct iscsi_cls_session *session = transport_class_to_session(cdev);
        struct iscsi_transport *t = session->transport;
        int param;

        if (attr == &dev_attr_sess_initial_r2t.attr)
                param = ISCSI_PARAM_INITIAL_R2T_EN;
        else if (attr == &dev_attr_sess_max_outstanding_r2t.attr)
                param = ISCSI_PARAM_MAX_R2T;
        else if (attr == &dev_attr_sess_immediate_data.attr)
                param = ISCSI_PARAM_IMM_DATA_EN;
        else if (attr == &dev_attr_sess_first_burst_len.attr)
                param = ISCSI_PARAM_FIRST_BURST;
        else if (attr == &dev_attr_sess_max_burst_len.attr)
                param = ISCSI_PARAM_MAX_BURST;
        else if (attr == &dev_attr_sess_data_pdu_in_order.attr)
                param = ISCSI_PARAM_PDU_INORDER_EN;
        else if (attr == &dev_attr_sess_data_seq_in_order.attr)
                param = ISCSI_PARAM_DATASEQ_INORDER_EN;
        else if (attr == &dev_attr_sess_erl.attr)
                param = ISCSI_PARAM_ERL;
        else if (attr == &dev_attr_sess_targetname.attr)
                param = ISCSI_PARAM_TARGET_NAME;
        else if (attr == &dev_attr_sess_tpgt.attr)
                param = ISCSI_PARAM_TPGT;
        else if (attr == &dev_attr_sess_password.attr)
                param = ISCSI_PARAM_USERNAME;
        else if (attr == &dev_attr_sess_password_in.attr)
                param = ISCSI_PARAM_USERNAME_IN;
        else if (attr == &dev_attr_sess_username.attr)
                param = ISCSI_PARAM_PASSWORD;
        else if (attr == &dev_attr_sess_username_in.attr)
                param = ISCSI_PARAM_PASSWORD_IN;
        else if (attr == &dev_attr_sess_fast_abort.attr)
                param = ISCSI_PARAM_FAST_ABORT;
        else if (attr == &dev_attr_sess_abort_tmo.attr)
                param = ISCSI_PARAM_ABORT_TMO;
        else if (attr == &dev_attr_sess_lu_reset_tmo.attr)
                param = ISCSI_PARAM_LU_RESET_TMO;
        else if (attr == &dev_attr_sess_tgt_reset_tmo.attr)
                param = ISCSI_PARAM_TGT_RESET_TMO;
        else if (attr == &dev_attr_sess_ifacename.attr)
                param = ISCSI_PARAM_IFACE_NAME;
        else if (attr == &dev_attr_sess_initiatorname.attr)
                param = ISCSI_PARAM_INITIATOR_NAME;
        else if (attr == &dev_attr_sess_targetalias.attr)
                param = ISCSI_PARAM_TARGET_ALIAS;
        else if (attr == &dev_attr_priv_sess_recovery_tmo.attr)
                return S_IRUGO | S_IWUSR;
        else if (attr == &dev_attr_priv_sess_state.attr)
                return S_IRUGO;
        else {
                WARN_ONCE(1, "Invalid session attr");
                return 0;
        }

        return t->attr_is_visible(ISCSI_PARAM, param);
}

static struct attribute_group iscsi_session_group = {
        .attrs = iscsi_session_attrs,
        .is_visible = iscsi_session_attr_is_visible,
};

/*
 * iSCSI host attrs
 */
#define iscsi_host_attr_show(param)                                     \
static ssize_t                                                          \
show_host_param_##param(struct device *dev,                             \
                        struct device_attribute *attr, char *buf)       \
{                                                                       \
        struct Scsi_Host *shost = transport_class_to_shost(dev);        \
        struct iscsi_internal *priv = to_iscsi_internal(shost->transportt); \
        return priv->iscsi_transport->get_host_param(shost, param, buf); \
}

#define iscsi_host_attr(field, param)                                   \
        iscsi_host_attr_show(param)                                     \
static ISCSI_CLASS_ATTR(host, field, S_IRUGO, show_host_param_##param,  \
                        NULL);

iscsi_host_attr(netdev, ISCSI_HOST_PARAM_NETDEV_NAME);
iscsi_host_attr(hwaddress, ISCSI_HOST_PARAM_HWADDRESS);
iscsi_host_attr(ipaddress, ISCSI_HOST_PARAM_IPADDRESS);
iscsi_host_attr(initiatorname, ISCSI_HOST_PARAM_INITIATOR_NAME);

static struct attribute *iscsi_host_attrs[] = {
        &dev_attr_host_netdev.attr,
        &dev_attr_host_hwaddress.attr,
        &dev_attr_host_ipaddress.attr,
        &dev_attr_host_initiatorname.attr,
        NULL,
};

static mode_t iscsi_host_attr_is_visible(struct kobject *kobj,
                                         struct attribute *attr, int i)
{
        struct device *cdev = container_of(kobj, struct device, kobj);
        struct Scsi_Host *shost = transport_class_to_shost(cdev);
        struct iscsi_internal *priv = to_iscsi_internal(shost->transportt);
        int param;

        if (attr == &dev_attr_host_netdev.attr)
                param = ISCSI_HOST_PARAM_NETDEV_NAME;
        else if (attr == &dev_attr_host_hwaddress.attr)
                param = ISCSI_HOST_PARAM_HWADDRESS;
        else if (attr == &dev_attr_host_ipaddress.attr)
                param = ISCSI_HOST_PARAM_IPADDRESS;
        else if (attr == &dev_attr_host_initiatorname.attr)
                param = ISCSI_HOST_PARAM_INITIATOR_NAME;
        else {
                WARN_ONCE(1, "Invalid host attr");
                return 0;
        }

        return priv->iscsi_transport->attr_is_visible(ISCSI_HOST_PARAM, param);
}

static struct attribute_group iscsi_host_group = {
        .attrs = iscsi_host_attrs,
        .is_visible = iscsi_host_attr_is_visible,
};

static int iscsi_session_match(struct attribute_container *cont,
                           struct device *dev)
{
        struct iscsi_cls_session *session;
        struct Scsi_Host *shost;
        struct iscsi_internal *priv;

        if (!iscsi_is_session_dev(dev))
                return 0;

        session = iscsi_dev_to_session(dev);
        shost = iscsi_session_to_shost(session);
        if (!shost->transportt)
                return 0;

        priv = to_iscsi_internal(shost->transportt);
        if (priv->session_cont.ac.class != &iscsi_session_class.class)
                return 0;

        return &priv->session_cont.ac == cont;
}

static int iscsi_conn_match(struct attribute_container *cont,
                           struct device *dev)
{
        struct iscsi_cls_session *session;
        struct iscsi_cls_conn *conn;
        struct Scsi_Host *shost;
        struct iscsi_internal *priv;

        if (!iscsi_is_conn_dev(dev))
                return 0;

        conn = iscsi_dev_to_conn(dev);
        session = iscsi_dev_to_session(conn->dev.parent);
        shost = iscsi_session_to_shost(session);

        if (!shost->transportt)
                return 0;

        priv = to_iscsi_internal(shost->transportt);
        if (priv->conn_cont.ac.class != &iscsi_connection_class.class)
                return 0;

        return &priv->conn_cont.ac == cont;
}

static int iscsi_host_match(struct attribute_container *cont,
                            struct device *dev)
{
        struct Scsi_Host *shost;
        struct iscsi_internal *priv;

        if (!scsi_is_host_device(dev))
                return 0;

        shost = dev_to_shost(dev);
        if (!shost->transportt  ||
            shost->transportt->host_attrs.ac.class != &iscsi_host_class.class)
                return 0;

        priv = to_iscsi_internal(shost->transportt);
        return &priv->t.host_attrs.ac == cont;
}

struct scsi_transport_template *
iscsi_register_transport(struct iscsi_transport *tt)
{
        struct iscsi_internal *priv;
        unsigned long flags;
        int err;

        BUG_ON(!tt);

        priv = iscsi_if_transport_lookup(tt);
        if (priv)
                return NULL;

        priv = kzalloc(sizeof(*priv), GFP_KERNEL);
        if (!priv)
                return NULL;
        INIT_LIST_HEAD(&priv->list);
        priv->iscsi_transport = tt;
        priv->t.user_scan = iscsi_user_scan;
        priv->t.create_work_queue = 1;

        priv->dev.class = &iscsi_transport_class;
        dev_set_name(&priv->dev, "%s", tt->name);
        err = device_register(&priv->dev);
        if (err)
                goto free_priv;

        err = sysfs_create_group(&priv->dev.kobj, &iscsi_transport_group);
        if (err)
                goto unregister_dev;

        /* host parameters */
        priv->t.host_attrs.ac.class = &iscsi_host_class.class;
        priv->t.host_attrs.ac.match = iscsi_host_match;
        priv->t.host_attrs.ac.grp = &iscsi_host_group;
        priv->t.host_size = sizeof(struct iscsi_cls_host);
        transport_container_register(&priv->t.host_attrs);

        /* connection parameters */
        priv->conn_cont.ac.class = &iscsi_connection_class.class;
        priv->conn_cont.ac.match = iscsi_conn_match;
        priv->conn_cont.ac.grp = &iscsi_conn_group;
        transport_container_register(&priv->conn_cont);

        /* session parameters */
        priv->session_cont.ac.class = &iscsi_session_class.class;
        priv->session_cont.ac.match = iscsi_session_match;
        priv->session_cont.ac.grp = &iscsi_session_group;
        transport_container_register(&priv->session_cont);

        spin_lock_irqsave(&iscsi_transport_lock, flags);
        list_add(&priv->list, &iscsi_transports);
        spin_unlock_irqrestore(&iscsi_transport_lock, flags);

        printk(KERN_NOTICE "iscsi: registered transport (%s)\n", tt->name);
        return &priv->t;

unregister_dev:
        device_unregister(&priv->dev);
        return NULL;
free_priv:
        kfree(priv);
        return NULL;
}
EXPORT_SYMBOL_GPL(iscsi_register_transport);

int iscsi_unregister_transport(struct iscsi_transport *tt)
{
        struct iscsi_internal *priv;
        unsigned long flags;

        BUG_ON(!tt);

        mutex_lock(&rx_queue_mutex);

        priv = iscsi_if_transport_lookup(tt);
        BUG_ON (!priv);

        spin_lock_irqsave(&iscsi_transport_lock, flags);
        list_del(&priv->list);
        spin_unlock_irqrestore(&iscsi_transport_lock, flags);

        transport_container_unregister(&priv->conn_cont);
        transport_container_unregister(&priv->session_cont);
        transport_container_unregister(&priv->t.host_attrs);

        sysfs_remove_group(&priv->dev.kobj, &iscsi_transport_group);
        device_unregister(&priv->dev);
        mutex_unlock(&rx_queue_mutex);

        return 0;
}
EXPORT_SYMBOL_GPL(iscsi_unregister_transport);

static __init int iscsi_transport_init(void)
{
        int err;

        printk(KERN_INFO "Loading iSCSI transport class v%s.\n",
                ISCSI_TRANSPORT_VERSION);

        atomic_set(&iscsi_session_nr, 0);

        err = class_register(&iscsi_transport_class);
        if (err)
                return err;

        err = class_register(&iscsi_endpoint_class);
        if (err)
                goto unregister_transport_class;

        err = class_register(&iscsi_iface_class);
        if (err)
                goto unregister_endpoint_class;

        err = transport_class_register(&iscsi_host_class);
        if (err)
                goto unregister_iface_class;

        err = transport_class_register(&iscsi_connection_class);
        if (err)
                goto unregister_host_class;

        err = transport_class_register(&iscsi_session_class);
        if (err)
                goto unregister_conn_class;

        nls = netlink_kernel_create(&init_net, NETLINK_ISCSI, 1, iscsi_if_rx,
                                    NULL, THIS_MODULE);
        if (!nls) {
                err = -ENOBUFS;
                goto unregister_session_class;
        }

        iscsi_eh_timer_workq = create_singlethread_workqueue("iscsi_eh");
        if (!iscsi_eh_timer_workq)
                goto release_nls;

        return 0;

release_nls:
        netlink_kernel_release(nls);
unregister_session_class:
        transport_class_unregister(&iscsi_session_class);
unregister_conn_class:
        transport_class_unregister(&iscsi_connection_class);
unregister_host_class:
        transport_class_unregister(&iscsi_host_class);
unregister_iface_class:
        class_unregister(&iscsi_iface_class);
unregister_endpoint_class:
        class_unregister(&iscsi_endpoint_class);
unregister_transport_class:
        class_unregister(&iscsi_transport_class);
        return err;
}

static void __exit iscsi_transport_exit(void)
{
        destroy_workqueue(iscsi_eh_timer_workq);
        netlink_kernel_release(nls);
        transport_class_unregister(&iscsi_connection_class);
        transport_class_unregister(&iscsi_session_class);
        transport_class_unregister(&iscsi_host_class);
        class_unregister(&iscsi_endpoint_class);
        class_unregister(&iscsi_iface_class);
        class_unregister(&iscsi_transport_class);
}

module_init(iscsi_transport_init);
module_exit(iscsi_transport_exit);

MODULE_AUTHOR("Mike Christie <michaelc@cs.wisc.edu>, "
              "Dmitry Yusupov <dmitry_yus@yahoo.com>, "
              "Alex Aizman <itn780@yahoo.com>");
MODULE_DESCRIPTION("iSCSI Transport Interface");
MODULE_LICENSE("GPL");
MODULE_VERSION(ISCSI_TRANSPORT_VERSION);
MODULE_ALIAS_NET_PF_PROTO(PF_NETLINK, NETLINK_ISCSI);