/*
 * 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 openib-general@openib.org
 *
 * 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 <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) {
                printk(KERN_ERR "iscsi_iser: datalen %d (hdr) != %d (IB) \n",
                       datalen, rx_data_len);
                rc = ISCSI_ERR_DATALEN;
                goto error;
        }

        /* 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->headers_initialized  = 1;
        iser_task->iser_conn            = iser_conn;
        return 0;
}
/**
 * iscsi_iser_task_init - Initialize task
 * @task: iscsi task
 *
 * Initialize the task for the scsi command or mgmt command.
 */
static int
iscsi_iser_task_init(struct iscsi_task *task)
{
        struct iscsi_iser_task *iser_task = task->dd_data;

        if (!iser_task->headers_initialized)
                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;
}

/**
 * iscsi_iser_mtask_xmit - xmit management(immediate) task
 * @conn: iscsi connection
 * @task: task management task
 *
 * Notes:
 *      The function can return -EAGAIN in which case caller must
 *      call it again later, or recover. '0' return code means successful
 *      xmit.
 *
 **/
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;

        /* 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;

        /* 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 int
iscsi_iser_conn_start(struct iscsi_cls_conn *cls_conn)
{
        struct iscsi_conn *conn = cls_conn->dd_data;
        int err;

        err = iser_conn_set_full_featured_mode(conn);
        if (err)
                return err;

        return iscsi_conn_start(cls_conn);
}

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 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) {
                iscsi_destroy_endpoint(ep);
                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 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,
        .param_mask             = ISCSI_MAX_RECV_DLENGTH |
                                  ISCSI_MAX_XMIT_DLENGTH |
                                  ISCSI_HDRDGST_EN |
                                  ISCSI_DATADGST_EN |
                                  ISCSI_INITIAL_R2T_EN |
                                  ISCSI_MAX_R2T |
                                  ISCSI_IMM_DATA_EN |
                                  ISCSI_FIRST_BURST |
                                  ISCSI_MAX_BURST |
                                  ISCSI_PDU_INORDER_EN |
                                  ISCSI_DATASEQ_INORDER_EN |
                                  ISCSI_EXP_STATSN |
                                  ISCSI_PERSISTENT_PORT |
                                  ISCSI_PERSISTENT_ADDRESS |
                                  ISCSI_TARGET_NAME | ISCSI_TPGT |
                                  ISCSI_USERNAME | ISCSI_PASSWORD |
                                  ISCSI_USERNAME_IN | ISCSI_PASSWORD_IN |
                                  ISCSI_FAST_ABORT | ISCSI_ABORT_TMO |
                                  ISCSI_LU_RESET_TMO | ISCSI_TGT_RESET_TMO |
                                  ISCSI_PING_TMO | ISCSI_RECV_TMO |
                                  ISCSI_IFACE_NAME | ISCSI_INITIATOR_NAME,
        .host_param_mask        = ISCSI_HOST_HWADDRESS |
                                  ISCSI_HOST_NETDEV_NAME |
                                  ISCSI_HOST_INITIATOR_NAME,
        /* 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,
        .set_param              = iscsi_iser_set_param,
        .get_conn_param         = iscsi_conn_get_param,
        .get_session_param      = iscsi_session_get_param,
        .start_conn             = iscsi_iser_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);