iscsi_iser.c

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/*
 * iSCSI Initiator over iSER Data-Path
 *
 * Copyright (C) 2004 Dmitry Yusupov
 * Copyright (C) 2004 Alex Aizman
 * Copyright (C) 2005 Mike Christie
 * Copyright (c) 2005, 2006 Voltaire, Inc. All rights reserved.
 * maintained by [email protected]
 *
 * This software is available to you under a choice of one of two
 * licenses.  You may choose to be licensed under the terms of the GNU
 * General Public License (GPL) Version 2, available from the file
 * COPYING in the main directory of this source tree, or the
 * OpenIB.org BSD license below:
 *
 *     Redistribution and use in source and binary forms, with or
 *     without modification, are permitted provided that the following
 *     conditions are met:
 *
 *  - Redistributions of source code must retain the above
 *    copyright notice, this list of conditions and the following
 *    disclaimer.
 *
 *  - Redistributions in binary form must reproduce the above
 *    copyright notice, this list of conditions and the following
 *    disclaimer in the documentation and/or other materials
 *    provided with the distribution.
 *
 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
 * EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
 * MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
 * NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS
 * BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN
 * ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN
 * CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
 * SOFTWARE.
 *
 * Credits:
 *  Christoph Hellwig
 *  FUJITA Tomonori
 *  Arne Redlich
 *  Zhenyu Wang
 * Modified by:
 *      Erez Zilber
 */

#include <linux/types.h>
#include <linux/list.h>
#include <linux/hardirq.h>
#include <linux/kfifo.h>
#include <linux/blkdev.h>
#include <linux/init.h>
#include <linux/ioctl.h>
#include <linux/cdev.h>
#include <linux/in.h>
#include <linux/net.h>
#include <linux/scatterlist.h>
#include <linux/delay.h>
#include <linux/slab.h>
#include <linux/module.h>

#include <net/sock.h>

#include <asm/uaccess.h>

#include <scsi/scsi_cmnd.h>
#include <scsi/scsi_device.h>
#include <scsi/scsi_eh.h>
#include <scsi/scsi_tcq.h>
#include <scsi/scsi_host.h>
#include <scsi/scsi.h>
#include <scsi/scsi_transport_iscsi.h>

#include "iscsi_iser.h"

static struct scsi_host_template iscsi_iser_sht;
static struct iscsi_transport iscsi_iser_transport;
static struct scsi_transport_template *iscsi_iser_scsi_transport;

static unsigned int iscsi_max_lun = 512;
module_param_named(max_lun, iscsi_max_lun, uint, S_IRUGO);

int iser_debug_level = 0;

MODULE_DESCRIPTION("iSER (iSCSI Extensions for RDMA) Datamover "
           "v" DRV_VER " (" DRV_DATE ")");
MODULE_LICENSE("Dual BSD/GPL");
MODULE_AUTHOR("Alex Nezhinsky, Dan Bar Dov, Or Gerlitz");

module_param_named(debug_level, iser_debug_level, int, 0644);
MODULE_PARM_DESC(debug_level, "Enable debug tracing if > 0 (default:disabled)");

struct iser_global ig;

void
iscsi_iser_recv(struct iscsi_conn *conn,
        struct iscsi_hdr *hdr, char *rx_data, int rx_data_len)
{
    int rc = 0;
    int datalen;
    int ahslen;

    /* verify PDU length */
    datalen = ntoh24(hdr->dlength);
    if (datalen > rx_data_len || (datalen + 4) < rx_data_len) {
        iser_err("wrong datalen %d (hdr), %d (IB)\n",
            datalen, rx_data_len);
        rc = ISCSI_ERR_DATALEN;
        goto error;
    }

    if (datalen != rx_data_len)
        iser_dbg("aligned datalen (%d) hdr, %d (IB)\n",
            datalen, rx_data_len);

    /* read AHS */
    ahslen = hdr->hlength * 4;

    rc = iscsi_complete_pdu(conn, hdr, rx_data, rx_data_len);
    if (rc && rc != ISCSI_ERR_NO_SCSI_CMD)
        goto error;

    return;
error:
    iscsi_conn_failure(conn, rc);
}

static int iscsi_iser_pdu_alloc(struct iscsi_task *task, uint8_t opcode)
{
    struct iscsi_iser_task *iser_task = task->dd_data;

    task->hdr = (struct iscsi_hdr *)&iser_task->desc.iscsi_header;
    task->hdr_max = sizeof(iser_task->desc.iscsi_header);
    return 0;
}

int iser_initialize_task_headers(struct iscsi_task *task,
                        struct iser_tx_desc *tx_desc)
{
    struct iscsi_iser_conn *iser_conn = task->conn->dd_data;
    struct iser_device     *device    = iser_conn->ib_conn->device;
    struct iscsi_iser_task *iser_task = task->dd_data;
    u64 dma_addr;

    dma_addr = ib_dma_map_single(device->ib_device, (void *)tx_desc,
                ISER_HEADERS_LEN, DMA_TO_DEVICE);
    if (ib_dma_mapping_error(device->ib_device, dma_addr))
        return -ENOMEM;

    tx_desc->dma_addr = dma_addr;
    tx_desc->tx_sg[0].addr   = tx_desc->dma_addr;
    tx_desc->tx_sg[0].length = ISER_HEADERS_LEN;
    tx_desc->tx_sg[0].lkey   = device->mr->lkey;

    iser_task->iser_conn        = iser_conn;
    return 0;
}
static int
iscsi_iser_task_init(struct iscsi_task *task)
{
    struct iscsi_iser_task *iser_task = task->dd_data;

    if (iser_initialize_task_headers(task, &iser_task->desc))
            return -ENOMEM;

    /* mgmt task */
    if (!task->sc)
        return 0;

    iser_task->command_sent = 0;
    iser_task_rdma_init(iser_task);
    return 0;
}

static int
iscsi_iser_mtask_xmit(struct iscsi_conn *conn, struct iscsi_task *task)
{
    int error = 0;

    iser_dbg("mtask xmit [cid %d itt 0x%x]\n", conn->id, task->itt);

    error = iser_send_control(conn, task);

    /* since iser xmits control with zero copy, tasks can not be recycled
     * right after sending them.
     * The recycling scheme is based on whether a response is expected
     * - if yes, the task is recycled at iscsi_complete_pdu
     * - if no,  the task is recycled at iser_snd_completion
     */
    return error;
}

static int
iscsi_iser_task_xmit_unsol_data(struct iscsi_conn *conn,
                 struct iscsi_task *task)
{
    struct iscsi_r2t_info *r2t = &task->unsol_r2t;
    struct iscsi_data hdr;
    int error = 0;

    /* Send data-out PDUs while there's still unsolicited data to send */
    while (iscsi_task_has_unsol_data(task)) {
        iscsi_prep_data_out_pdu(task, r2t, &hdr);
        iser_dbg("Sending data-out: itt 0x%x, data count %d\n",
               hdr.itt, r2t->data_count);

        /* the buffer description has been passed with the command */
        /* Send the command */
        error = iser_send_data_out(conn, task, &hdr);
        if (error) {
            r2t->datasn--;
            goto iscsi_iser_task_xmit_unsol_data_exit;
        }
        r2t->sent += r2t->data_count;
        iser_dbg("Need to send %d more as data-out PDUs\n",
               r2t->data_length - r2t->sent);
    }

iscsi_iser_task_xmit_unsol_data_exit:
    return error;
}

static int
iscsi_iser_task_xmit(struct iscsi_task *task)
{
    struct iscsi_conn *conn = task->conn;
    struct iscsi_iser_task *iser_task = task->dd_data;
    int error = 0;

    if (!task->sc)
        return iscsi_iser_mtask_xmit(conn, task);

    if (task->sc->sc_data_direction == DMA_TO_DEVICE) {
        BUG_ON(scsi_bufflen(task->sc) == 0);

        iser_dbg("cmd [itt %x total %d imm %d unsol_data %d\n",
               task->itt, scsi_bufflen(task->sc),
               task->imm_count, task->unsol_r2t.data_length);
    }

    iser_dbg("ctask xmit [cid %d itt 0x%x]\n",
           conn->id, task->itt);

    /* Send the cmd PDU */
    if (!iser_task->command_sent) {
        error = iser_send_command(conn, task);
        if (error)
            goto iscsi_iser_task_xmit_exit;
        iser_task->command_sent = 1;
    }

    /* Send unsolicited data-out PDU(s) if necessary */
    if (iscsi_task_has_unsol_data(task))
        error = iscsi_iser_task_xmit_unsol_data(conn, task);

 iscsi_iser_task_xmit_exit:
    return error;
}

static void iscsi_iser_cleanup_task(struct iscsi_task *task)
{
    struct iscsi_iser_task *iser_task = task->dd_data;
    struct iser_tx_desc *tx_desc = &iser_task->desc;

    struct iscsi_iser_conn *iser_conn = task->conn->dd_data;
    struct iser_device     *device    = iser_conn->ib_conn->device;

    ib_dma_unmap_single(device->ib_device,
        tx_desc->dma_addr, ISER_HEADERS_LEN, DMA_TO_DEVICE);

    /* mgmt tasks do not need special cleanup */
    if (!task->sc)
        return;

    if (iser_task->status == ISER_TASK_STATUS_STARTED) {
        iser_task->status = ISER_TASK_STATUS_COMPLETED;
        iser_task_rdma_finalize(iser_task);
    }
}

static struct iscsi_cls_conn *
iscsi_iser_conn_create(struct iscsi_cls_session *cls_session, uint32_t conn_idx)
{
    struct iscsi_conn *conn;
    struct iscsi_cls_conn *cls_conn;
    struct iscsi_iser_conn *iser_conn;

    cls_conn = iscsi_conn_setup(cls_session, sizeof(*iser_conn), conn_idx);
    if (!cls_conn)
        return NULL;
    conn = cls_conn->dd_data;

    /*
     * due to issues with the login code re iser sematics
     * this not set in iscsi_conn_setup - FIXME
     */
    conn->max_recv_dlength = ISER_RECV_DATA_SEG_LEN;

    iser_conn = conn->dd_data;
    conn->dd_data = iser_conn;
    iser_conn->iscsi_conn = conn;

    return cls_conn;
}

static void
iscsi_iser_conn_destroy(struct iscsi_cls_conn *cls_conn)
{
    struct iscsi_conn *conn = cls_conn->dd_data;
    struct iscsi_iser_conn *iser_conn = conn->dd_data;
    struct iser_conn *ib_conn = iser_conn->ib_conn;

    iscsi_conn_teardown(cls_conn);
    /*
     * Userspace will normally call the stop callback and
     * already have freed the ib_conn, but if it goofed up then
     * we free it here.
     */
    if (ib_conn) {
        ib_conn->iser_conn = NULL;
        iser_conn_put(ib_conn, 1); /* deref iscsi/ib conn unbinding */
    }
}

static int
iscsi_iser_conn_bind(struct iscsi_cls_session *cls_session,
             struct iscsi_cls_conn *cls_conn, uint64_t transport_eph,
             int is_leading)
{
    struct iscsi_conn *conn = cls_conn->dd_data;
    struct iscsi_iser_conn *iser_conn;
    struct iser_conn *ib_conn;
    struct iscsi_endpoint *ep;
    int error;

    error = iscsi_conn_bind(cls_session, cls_conn, is_leading);
    if (error)
        return error;

    /* the transport ep handle comes from user space so it must be
     * verified against the global ib connections list */
    ep = iscsi_lookup_endpoint(transport_eph);
    if (!ep) {
        iser_err("can't bind eph %llx\n",
             (unsigned long long)transport_eph);
        return -EINVAL;
    }
    ib_conn = ep->dd_data;

    if (iser_alloc_rx_descriptors(ib_conn))
        return -ENOMEM;

    /* binds the iSER connection retrieved from the previously
     * connected ep_handle to the iSCSI layer connection. exchanges
     * connection pointers */
    iser_err("binding iscsi/iser conn %p %p to ib_conn %p\n",
                    conn, conn->dd_data, ib_conn);
    iser_conn = conn->dd_data;
    ib_conn->iser_conn = iser_conn;
    iser_conn->ib_conn  = ib_conn;
    iser_conn_get(ib_conn); /* ref iscsi/ib conn binding */
    return 0;
}

static void
iscsi_iser_conn_stop(struct iscsi_cls_conn *cls_conn, int flag)
{
    struct iscsi_conn *conn = cls_conn->dd_data;
    struct iscsi_iser_conn *iser_conn = conn->dd_data;
    struct iser_conn *ib_conn = iser_conn->ib_conn;

    /*
     * Userspace may have goofed up and not bound the connection or
     * might have only partially setup the connection.
     */
    if (ib_conn) {
        iscsi_conn_stop(cls_conn, flag);
        /*
         * There is no unbind event so the stop callback
         * must release the ref from the bind.
         */
        iser_conn_put(ib_conn, 1); /* deref iscsi/ib conn unbinding */
    }
    iser_conn->ib_conn = NULL;
}

static void iscsi_iser_session_destroy(struct iscsi_cls_session *cls_session)
{
    struct Scsi_Host *shost = iscsi_session_to_shost(cls_session);

    iscsi_session_teardown(cls_session);
    iscsi_host_remove(shost);
    iscsi_host_free(shost);
}

static struct iscsi_cls_session *
iscsi_iser_session_create(struct iscsi_endpoint *ep,
              uint16_t cmds_max, uint16_t qdepth,
              uint32_t initial_cmdsn)
{
    struct iscsi_cls_session *cls_session;
    struct iscsi_session *session;
    struct Scsi_Host *shost;
    struct iser_conn *ib_conn;

    shost = iscsi_host_alloc(&iscsi_iser_sht, 0, 0);
    if (!shost)
        return NULL;
    shost->transportt = iscsi_iser_scsi_transport;
    shost->max_lun = iscsi_max_lun;
    shost->max_id = 0;
    shost->max_channel = 0;
    shost->max_cmd_len = 16;

    /*
     * older userspace tools (before 2.0-870) did not pass us
     * the leading conn's ep so this will be NULL;
     */
    if (ep)
        ib_conn = ep->dd_data;

    if (iscsi_host_add(shost,
               ep ? ib_conn->device->ib_device->dma_device : NULL))
        goto free_host;

    /*
     * we do not support setting can_queue cmd_per_lun from userspace yet
     * because we preallocate so many resources
     */
    cls_session = iscsi_session_setup(&iscsi_iser_transport, shost,
                      ISCSI_DEF_XMIT_CMDS_MAX, 0,
                      sizeof(struct iscsi_iser_task),
                      initial_cmdsn, 0);
    if (!cls_session)
        goto remove_host;
    session = cls_session->dd_data;

    shost->can_queue = session->scsi_cmds_max;
    return cls_session;

remove_host:
    iscsi_host_remove(shost);
free_host:
    iscsi_host_free(shost);
    return NULL;
}

static int
iscsi_iser_set_param(struct iscsi_cls_conn *cls_conn,
             enum iscsi_param param, char *buf, int buflen)
{
    int value;

    switch (param) {
    case ISCSI_PARAM_MAX_RECV_DLENGTH:
        /* TBD */
        break;
    case ISCSI_PARAM_HDRDGST_EN:
        sscanf(buf, "%d", &value);
        if (value) {
            printk(KERN_ERR "DataDigest wasn't negotiated to None");
            return -EPROTO;
        }
        break;
    case ISCSI_PARAM_DATADGST_EN:
        sscanf(buf, "%d", &value);
        if (value) {
            printk(KERN_ERR "DataDigest wasn't negotiated to None");
            return -EPROTO;
        }
        break;
    case ISCSI_PARAM_IFMARKER_EN:
        sscanf(buf, "%d", &value);
        if (value) {
            printk(KERN_ERR "IFMarker wasn't negotiated to No");
            return -EPROTO;
        }
        break;
    case ISCSI_PARAM_OFMARKER_EN:
        sscanf(buf, "%d", &value);
        if (value) {
            printk(KERN_ERR "OFMarker wasn't negotiated to No");
            return -EPROTO;
        }
        break;
    default:
        return iscsi_set_param(cls_conn, param, buf, buflen);
    }

    return 0;
}

static void
iscsi_iser_conn_get_stats(struct iscsi_cls_conn *cls_conn, struct iscsi_stats *stats)
{
    struct iscsi_conn *conn = cls_conn->dd_data;

    stats->txdata_octets = conn->txdata_octets;
    stats->rxdata_octets = conn->rxdata_octets;
    stats->scsicmd_pdus = conn->scsicmd_pdus_cnt;
    stats->dataout_pdus = conn->dataout_pdus_cnt;
    stats->scsirsp_pdus = conn->scsirsp_pdus_cnt;
    stats->datain_pdus = conn->datain_pdus_cnt; /* always 0 */
    stats->r2t_pdus = conn->r2t_pdus_cnt; /* always 0 */
    stats->tmfcmd_pdus = conn->tmfcmd_pdus_cnt;
    stats->tmfrsp_pdus = conn->tmfrsp_pdus_cnt;
    stats->custom_length = 4;
    strcpy(stats->custom[0].desc, "qp_tx_queue_full");
    stats->custom[0].value = 0; /* TB iser_conn->qp_tx_queue_full; */
    strcpy(stats->custom[1].desc, "fmr_map_not_avail");
    stats->custom[1].value = 0; /* TB iser_conn->fmr_map_not_avail */;
    strcpy(stats->custom[2].desc, "eh_abort_cnt");
    stats->custom[2].value = conn->eh_abort_cnt;
    strcpy(stats->custom[3].desc, "fmr_unalign_cnt");
    stats->custom[3].value = conn->fmr_unalign_cnt;
}

static int iscsi_iser_get_ep_param(struct iscsi_endpoint *ep,
                   enum iscsi_param param, char *buf)
{
    struct iser_conn *ib_conn = ep->dd_data;
    int len;

    switch (param) {
    case ISCSI_PARAM_CONN_PORT:
    case ISCSI_PARAM_CONN_ADDRESS:
        if (!ib_conn || !ib_conn->cma_id)
            return -ENOTCONN;

        return iscsi_conn_get_addr_param((struct sockaddr_storage *)
                    &ib_conn->cma_id->route.addr.dst_addr,
                    param, buf);
        break;
    default:
        return -ENOSYS;
    }

    return len;
}

static struct iscsi_endpoint *
iscsi_iser_ep_connect(struct Scsi_Host *shost, struct sockaddr *dst_addr,
              int non_blocking)
{
    int err;
    struct iser_conn *ib_conn;
    struct iscsi_endpoint *ep;

    ep = iscsi_create_endpoint(sizeof(*ib_conn));
    if (!ep)
        return ERR_PTR(-ENOMEM);

    ib_conn = ep->dd_data;
    ib_conn->ep = ep;
    iser_conn_init(ib_conn);

    err = iser_connect(ib_conn, NULL, (struct sockaddr_in *)dst_addr,
               non_blocking);
    if (err)
        return ERR_PTR(err);

    return ep;
}

static int
iscsi_iser_ep_poll(struct iscsi_endpoint *ep, int timeout_ms)
{
    struct iser_conn *ib_conn;
    int rc;

    ib_conn = ep->dd_data;
    rc = wait_event_interruptible_timeout(ib_conn->wait,
                 ib_conn->state == ISER_CONN_UP,
                 msecs_to_jiffies(timeout_ms));

    /* if conn establishment failed, return error code to iscsi */
    if (!rc &&
        (ib_conn->state == ISER_CONN_TERMINATING ||
         ib_conn->state == ISER_CONN_DOWN))
        rc = -1;

    iser_err("ib conn %p rc = %d\n", ib_conn, rc);

    if (rc > 0)
        return 1; /* success, this is the equivalent of POLLOUT */
    else if (!rc)
        return 0; /* timeout */
    else
        return rc; /* signal */
}

static void
iscsi_iser_ep_disconnect(struct iscsi_endpoint *ep)
{
    struct iser_conn *ib_conn;

    ib_conn = ep->dd_data;
    if (ib_conn->iser_conn)
        /*
         * Must suspend xmit path if the ep is bound to the
         * iscsi_conn, so we know we are not accessing the ib_conn
         * when we free it.
         *
         * This may not be bound if the ep poll failed.
         */
        iscsi_suspend_tx(ib_conn->iser_conn->iscsi_conn);


    iser_err("ib conn %p state %d\n",ib_conn, ib_conn->state);
    iser_conn_terminate(ib_conn);
}

static umode_t iser_attr_is_visible(int param_type, int param)
{
    switch (param_type) {
    case ISCSI_HOST_PARAM:
        switch (param) {
        case ISCSI_HOST_PARAM_NETDEV_NAME:
        case ISCSI_HOST_PARAM_HWADDRESS:
        case ISCSI_HOST_PARAM_INITIATOR_NAME:
            return S_IRUGO;
        default:
            return 0;
        }
    case ISCSI_PARAM:
        switch (param) {
        case ISCSI_PARAM_MAX_RECV_DLENGTH:
        case ISCSI_PARAM_MAX_XMIT_DLENGTH:
        case ISCSI_PARAM_HDRDGST_EN:
        case ISCSI_PARAM_DATADGST_EN:
        case ISCSI_PARAM_CONN_ADDRESS:
        case ISCSI_PARAM_CONN_PORT:
        case ISCSI_PARAM_EXP_STATSN:
        case ISCSI_PARAM_PERSISTENT_ADDRESS:
        case ISCSI_PARAM_PERSISTENT_PORT:
        case ISCSI_PARAM_PING_TMO:
        case ISCSI_PARAM_RECV_TMO:
        case ISCSI_PARAM_INITIAL_R2T_EN:
        case ISCSI_PARAM_MAX_R2T:
        case ISCSI_PARAM_IMM_DATA_EN:
        case ISCSI_PARAM_FIRST_BURST:
        case ISCSI_PARAM_MAX_BURST:
        case ISCSI_PARAM_PDU_INORDER_EN:
        case ISCSI_PARAM_DATASEQ_INORDER_EN:
        case ISCSI_PARAM_TARGET_NAME:
        case ISCSI_PARAM_TPGT:
        case ISCSI_PARAM_USERNAME:
        case ISCSI_PARAM_PASSWORD:
        case ISCSI_PARAM_USERNAME_IN:
        case ISCSI_PARAM_PASSWORD_IN:
        case ISCSI_PARAM_FAST_ABORT:
        case ISCSI_PARAM_ABORT_TMO:
        case ISCSI_PARAM_LU_RESET_TMO:
        case ISCSI_PARAM_TGT_RESET_TMO:
        case ISCSI_PARAM_IFACE_NAME:
        case ISCSI_PARAM_INITIATOR_NAME:
            return S_IRUGO;
        default:
            return 0;
        }
    }

    return 0;
}

static struct scsi_host_template iscsi_iser_sht = {
    .module                 = THIS_MODULE,
    .name                   = "iSCSI Initiator over iSER, v." DRV_VER,
    .queuecommand           = iscsi_queuecommand,
    .change_queue_depth = iscsi_change_queue_depth,
    .sg_tablesize           = ISCSI_ISER_SG_TABLESIZE,
    .max_sectors        = 1024,
    .cmd_per_lun            = ISER_DEF_CMD_PER_LUN,
    .eh_abort_handler       = iscsi_eh_abort,
    .eh_device_reset_handler= iscsi_eh_device_reset,
    .eh_target_reset_handler = iscsi_eh_recover_target,
    .target_alloc       = iscsi_target_alloc,
    .use_clustering         = DISABLE_CLUSTERING,
    .proc_name              = "iscsi_iser",
    .this_id                = -1,
};

static struct iscsi_transport iscsi_iser_transport = {
    .owner                  = THIS_MODULE,
    .name                   = "iser",
    .caps                   = CAP_RECOVERY_L0 | CAP_MULTI_R2T,
    /* session management */
    .create_session         = iscsi_iser_session_create,
    .destroy_session        = iscsi_iser_session_destroy,
    /* connection management */
    .create_conn            = iscsi_iser_conn_create,
    .bind_conn              = iscsi_iser_conn_bind,
    .destroy_conn           = iscsi_iser_conn_destroy,
    .attr_is_visible    = iser_attr_is_visible,
    .set_param              = iscsi_iser_set_param,
    .get_conn_param     = iscsi_conn_get_param,
    .get_ep_param       = iscsi_iser_get_ep_param,
    .get_session_param  = iscsi_session_get_param,
    .start_conn             = iscsi_conn_start,
    .stop_conn              = iscsi_iser_conn_stop,
    /* iscsi host params */
    .get_host_param     = iscsi_host_get_param,
    .set_host_param     = iscsi_host_set_param,
    /* IO */
    .send_pdu       = iscsi_conn_send_pdu,
    .get_stats      = iscsi_iser_conn_get_stats,
    .init_task      = iscsi_iser_task_init,
    .xmit_task      = iscsi_iser_task_xmit,
    .cleanup_task       = iscsi_iser_cleanup_task,
    .alloc_pdu      = iscsi_iser_pdu_alloc,
    /* recovery */
    .session_recovery_timedout = iscsi_session_recovery_timedout,

    .ep_connect             = iscsi_iser_ep_connect,
    .ep_poll                = iscsi_iser_ep_poll,
    .ep_disconnect          = iscsi_iser_ep_disconnect
};

static int __init iser_init(void)
{
    int err;

    iser_dbg("Starting iSER datamover...\n");

    if (iscsi_max_lun < 1) {
        printk(KERN_ERR "Invalid max_lun value of %u\n", iscsi_max_lun);
        return -EINVAL;
    }

    memset(&ig, 0, sizeof(struct iser_global));

    ig.desc_cache = kmem_cache_create("iser_descriptors",
                      sizeof(struct iser_tx_desc),
                      0, SLAB_HWCACHE_ALIGN,
                      NULL);
    if (ig.desc_cache == NULL)
        return -ENOMEM;

    /* device init is called only after the first addr resolution */
    mutex_init(&ig.device_list_mutex);
    INIT_LIST_HEAD(&ig.device_list);
    mutex_init(&ig.connlist_mutex);
    INIT_LIST_HEAD(&ig.connlist);

    iscsi_iser_scsi_transport = iscsi_register_transport(
                            &iscsi_iser_transport);
    if (!iscsi_iser_scsi_transport) {
        iser_err("iscsi_register_transport failed\n");
        err = -EINVAL;
        goto register_transport_failure;
    }

    return 0;

register_transport_failure:
    kmem_cache_destroy(ig.desc_cache);

    return err;
}

static void __exit iser_exit(void)
{
    iser_dbg("Removing iSER datamover...\n");
    iscsi_unregister_transport(&iscsi_iser_transport);
    kmem_cache_destroy(ig.desc_cache);
}

module_init(iser_init);
module_exit(iser_exit);