ib_srpt.c

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/*
 * Copyright (c) 2006 - 2009 Mellanox Technology Inc.  All rights reserved.
 * Copyright (C) 2008 - 2011 Bart Van Assche <[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.
 *
 */

#include <linux/module.h>
#include <linux/init.h>
#include <linux/slab.h>
#include <linux/err.h>
#include <linux/ctype.h>
#include <linux/kthread.h>
#include <linux/string.h>
#include <linux/delay.h>
#include <linux/atomic.h>
#include <scsi/scsi_tcq.h>
#include <target/configfs_macros.h>
#include <target/target_core_base.h>
#include <target/target_core_fabric_configfs.h>
#include <target/target_core_fabric.h>
#include <target/target_core_configfs.h>
#include "ib_srpt.h"

/* Name of this kernel module. */
#define DRV_NAME        "ib_srpt"
#define DRV_VERSION     "2.0.0"
#define DRV_RELDATE     "2011-02-14"

#define SRPT_ID_STRING  "Linux SRP target"

#undef pr_fmt
#define pr_fmt(fmt) DRV_NAME " " fmt

MODULE_AUTHOR("Vu Pham and Bart Van Assche");
MODULE_DESCRIPTION("InfiniBand SCSI RDMA Protocol target "
           "v" DRV_VERSION " (" DRV_RELDATE ")");
MODULE_LICENSE("Dual BSD/GPL");

/*
 * Global Variables
 */

static u64 srpt_service_guid;
static DEFINE_SPINLOCK(srpt_dev_lock);  /* Protects srpt_dev_list. */
static LIST_HEAD(srpt_dev_list);    /* List of srpt_device structures. */

static unsigned srp_max_req_size = DEFAULT_MAX_REQ_SIZE;
module_param(srp_max_req_size, int, 0444);
MODULE_PARM_DESC(srp_max_req_size,
         "Maximum size of SRP request messages in bytes.");

static int srpt_srq_size = DEFAULT_SRPT_SRQ_SIZE;
module_param(srpt_srq_size, int, 0444);
MODULE_PARM_DESC(srpt_srq_size,
         "Shared receive queue (SRQ) size.");

static int srpt_get_u64_x(char *buffer, struct kernel_param *kp)
{
    return sprintf(buffer, "0x%016llx", *(u64 *)kp->arg);
}
module_param_call(srpt_service_guid, NULL, srpt_get_u64_x, &srpt_service_guid,
          0444);
MODULE_PARM_DESC(srpt_service_guid,
         "Using this value for ioc_guid, id_ext, and cm_listen_id"
         " instead of using the node_guid of the first HCA.");

static struct ib_client srpt_client;
static struct target_fabric_configfs *srpt_target;
static void srpt_release_channel(struct srpt_rdma_ch *ch);
static int srpt_queue_status(struct se_cmd *cmd);

static inline
enum dma_data_direction opposite_dma_dir(enum dma_data_direction dir)
{
    switch (dir) {
    case DMA_TO_DEVICE: return DMA_FROM_DEVICE;
    case DMA_FROM_DEVICE:   return DMA_TO_DEVICE;
    default:        return dir;
    }
}

static inline const char *srpt_sdev_name(struct srpt_device *sdev)
{
    return sdev->device->name;
}

static enum rdma_ch_state srpt_get_ch_state(struct srpt_rdma_ch *ch)
{
    unsigned long flags;
    enum rdma_ch_state state;

    spin_lock_irqsave(&ch->spinlock, flags);
    state = ch->state;
    spin_unlock_irqrestore(&ch->spinlock, flags);
    return state;
}

static enum rdma_ch_state
srpt_set_ch_state(struct srpt_rdma_ch *ch, enum rdma_ch_state new_state)
{
    unsigned long flags;
    enum rdma_ch_state prev;

    spin_lock_irqsave(&ch->spinlock, flags);
    prev = ch->state;
    ch->state = new_state;
    spin_unlock_irqrestore(&ch->spinlock, flags);
    return prev;
}

static bool
srpt_test_and_set_ch_state(struct srpt_rdma_ch *ch, enum rdma_ch_state old,
               enum rdma_ch_state new)
{
    unsigned long flags;
    enum rdma_ch_state prev;

    spin_lock_irqsave(&ch->spinlock, flags);
    prev = ch->state;
    if (prev == old)
        ch->state = new;
    spin_unlock_irqrestore(&ch->spinlock, flags);
    return prev == old;
}

static void srpt_event_handler(struct ib_event_handler *handler,
                   struct ib_event *event)
{
    struct srpt_device *sdev;
    struct srpt_port *sport;

    sdev = ib_get_client_data(event->device, &srpt_client);
    if (!sdev || sdev->device != event->device)
        return;

    pr_debug("ASYNC event= %d on device= %s\n", event->event,
         srpt_sdev_name(sdev));

    switch (event->event) {
    case IB_EVENT_PORT_ERR:
        if (event->element.port_num <= sdev->device->phys_port_cnt) {
            sport = &sdev->port[event->element.port_num - 1];
            sport->lid = 0;
            sport->sm_lid = 0;
        }
        break;
    case IB_EVENT_PORT_ACTIVE:
    case IB_EVENT_LID_CHANGE:
    case IB_EVENT_PKEY_CHANGE:
    case IB_EVENT_SM_CHANGE:
    case IB_EVENT_CLIENT_REREGISTER:
        /* Refresh port data asynchronously. */
        if (event->element.port_num <= sdev->device->phys_port_cnt) {
            sport = &sdev->port[event->element.port_num - 1];
            if (!sport->lid && !sport->sm_lid)
                schedule_work(&sport->work);
        }
        break;
    default:
        printk(KERN_ERR "received unrecognized IB event %d\n",
               event->event);
        break;
    }
}

static void srpt_srq_event(struct ib_event *event, void *ctx)
{
    printk(KERN_INFO "SRQ event %d\n", event->event);
}

static void srpt_qp_event(struct ib_event *event, struct srpt_rdma_ch *ch)
{
    pr_debug("QP event %d on cm_id=%p sess_name=%s state=%d\n",
         event->event, ch->cm_id, ch->sess_name, srpt_get_ch_state(ch));

    switch (event->event) {
    case IB_EVENT_COMM_EST:
        ib_cm_notify(ch->cm_id, event->event);
        break;
    case IB_EVENT_QP_LAST_WQE_REACHED:
        if (srpt_test_and_set_ch_state(ch, CH_DRAINING,
                           CH_RELEASING))
            srpt_release_channel(ch);
        else
            pr_debug("%s: state %d - ignored LAST_WQE.\n",
                 ch->sess_name, srpt_get_ch_state(ch));
        break;
    default:
        printk(KERN_ERR "received unrecognized IB QP event %d\n",
               event->event);
        break;
    }
}

static void srpt_set_ioc(u8 *c_list, u32 slot, u8 value)
{
    u16 id;
    u8 tmp;

    id = (slot - 1) / 2;
    if (slot & 0x1) {
        tmp = c_list[id] & 0xf;
        c_list[id] = (value << 4) | tmp;
    } else {
        tmp = c_list[id] & 0xf0;
        c_list[id] = (value & 0xf) | tmp;
    }
}

static void srpt_get_class_port_info(struct ib_dm_mad *mad)
{
    struct ib_class_port_info *cif;

    cif = (struct ib_class_port_info *)mad->data;
    memset(cif, 0, sizeof *cif);
    cif->base_version = 1;
    cif->class_version = 1;
    cif->resp_time_value = 20;

    mad->mad_hdr.status = 0;
}

static void srpt_get_iou(struct ib_dm_mad *mad)
{
    struct ib_dm_iou_info *ioui;
    u8 slot;
    int i;

    ioui = (struct ib_dm_iou_info *)mad->data;
    ioui->change_id = __constant_cpu_to_be16(1);
    ioui->max_controllers = 16;

    /* set present for slot 1 and empty for the rest */
    srpt_set_ioc(ioui->controller_list, 1, 1);
    for (i = 1, slot = 2; i < 16; i++, slot++)
        srpt_set_ioc(ioui->controller_list, slot, 0);

    mad->mad_hdr.status = 0;
}

static void srpt_get_ioc(struct srpt_port *sport, u32 slot,
             struct ib_dm_mad *mad)
{
    struct srpt_device *sdev = sport->sdev;
    struct ib_dm_ioc_profile *iocp;

    iocp = (struct ib_dm_ioc_profile *)mad->data;

    if (!slot || slot > 16) {
        mad->mad_hdr.status
            = __constant_cpu_to_be16(DM_MAD_STATUS_INVALID_FIELD);
        return;
    }

    if (slot > 2) {
        mad->mad_hdr.status
            = __constant_cpu_to_be16(DM_MAD_STATUS_NO_IOC);
        return;
    }

    memset(iocp, 0, sizeof *iocp);
    strcpy(iocp->id_string, SRPT_ID_STRING);
    iocp->guid = cpu_to_be64(srpt_service_guid);
    iocp->vendor_id = cpu_to_be32(sdev->dev_attr.vendor_id);
    iocp->device_id = cpu_to_be32(sdev->dev_attr.vendor_part_id);
    iocp->device_version = cpu_to_be16(sdev->dev_attr.hw_ver);
    iocp->subsys_vendor_id = cpu_to_be32(sdev->dev_attr.vendor_id);
    iocp->subsys_device_id = 0x0;
    iocp->io_class = __constant_cpu_to_be16(SRP_REV16A_IB_IO_CLASS);
    iocp->io_subclass = __constant_cpu_to_be16(SRP_IO_SUBCLASS);
    iocp->protocol = __constant_cpu_to_be16(SRP_PROTOCOL);
    iocp->protocol_version = __constant_cpu_to_be16(SRP_PROTOCOL_VERSION);
    iocp->send_queue_depth = cpu_to_be16(sdev->srq_size);
    iocp->rdma_read_depth = 4;
    iocp->send_size = cpu_to_be32(srp_max_req_size);
    iocp->rdma_size = cpu_to_be32(min(sport->port_attrib.srp_max_rdma_size,
                      1U << 24));
    iocp->num_svc_entries = 1;
    iocp->op_cap_mask = SRP_SEND_TO_IOC | SRP_SEND_FROM_IOC |
        SRP_RDMA_READ_FROM_IOC | SRP_RDMA_WRITE_FROM_IOC;

    mad->mad_hdr.status = 0;
}

static void srpt_get_svc_entries(u64 ioc_guid,
                 u16 slot, u8 hi, u8 lo, struct ib_dm_mad *mad)
{
    struct ib_dm_svc_entries *svc_entries;

    WARN_ON(!ioc_guid);

    if (!slot || slot > 16) {
        mad->mad_hdr.status
            = __constant_cpu_to_be16(DM_MAD_STATUS_INVALID_FIELD);
        return;
    }

    if (slot > 2 || lo > hi || hi > 1) {
        mad->mad_hdr.status
            = __constant_cpu_to_be16(DM_MAD_STATUS_NO_IOC);
        return;
    }

    svc_entries = (struct ib_dm_svc_entries *)mad->data;
    memset(svc_entries, 0, sizeof *svc_entries);
    svc_entries->service_entries[0].id = cpu_to_be64(ioc_guid);
    snprintf(svc_entries->service_entries[0].name,
         sizeof(svc_entries->service_entries[0].name),
         "%s%016llx",
         SRP_SERVICE_NAME_PREFIX,
         ioc_guid);

    mad->mad_hdr.status = 0;
}

static void srpt_mgmt_method_get(struct srpt_port *sp, struct ib_mad *rq_mad,
                 struct ib_dm_mad *rsp_mad)
{
    u16 attr_id;
    u32 slot;
    u8 hi, lo;

    attr_id = be16_to_cpu(rq_mad->mad_hdr.attr_id);
    switch (attr_id) {
    case DM_ATTR_CLASS_PORT_INFO:
        srpt_get_class_port_info(rsp_mad);
        break;
    case DM_ATTR_IOU_INFO:
        srpt_get_iou(rsp_mad);
        break;
    case DM_ATTR_IOC_PROFILE:
        slot = be32_to_cpu(rq_mad->mad_hdr.attr_mod);
        srpt_get_ioc(sp, slot, rsp_mad);
        break;
    case DM_ATTR_SVC_ENTRIES:
        slot = be32_to_cpu(rq_mad->mad_hdr.attr_mod);
        hi = (u8) ((slot >> 8) & 0xff);
        lo = (u8) (slot & 0xff);
        slot = (u16) ((slot >> 16) & 0xffff);
        srpt_get_svc_entries(srpt_service_guid,
                     slot, hi, lo, rsp_mad);
        break;
    default:
        rsp_mad->mad_hdr.status =
            __constant_cpu_to_be16(DM_MAD_STATUS_UNSUP_METHOD_ATTR);
        break;
    }
}

static void srpt_mad_send_handler(struct ib_mad_agent *mad_agent,
                  struct ib_mad_send_wc *mad_wc)
{
    ib_destroy_ah(mad_wc->send_buf->ah);
    ib_free_send_mad(mad_wc->send_buf);
}

static void srpt_mad_recv_handler(struct ib_mad_agent *mad_agent,
                  struct ib_mad_recv_wc *mad_wc)
{
    struct srpt_port *sport = (struct srpt_port *)mad_agent->context;
    struct ib_ah *ah;
    struct ib_mad_send_buf *rsp;
    struct ib_dm_mad *dm_mad;

    if (!mad_wc || !mad_wc->recv_buf.mad)
        return;

    ah = ib_create_ah_from_wc(mad_agent->qp->pd, mad_wc->wc,
                  mad_wc->recv_buf.grh, mad_agent->port_num);
    if (IS_ERR(ah))
        goto err;

    BUILD_BUG_ON(offsetof(struct ib_dm_mad, data) != IB_MGMT_DEVICE_HDR);

    rsp = ib_create_send_mad(mad_agent, mad_wc->wc->src_qp,
                 mad_wc->wc->pkey_index, 0,
                 IB_MGMT_DEVICE_HDR, IB_MGMT_DEVICE_DATA,
                 GFP_KERNEL);
    if (IS_ERR(rsp))
        goto err_rsp;

    rsp->ah = ah;

    dm_mad = rsp->mad;
    memcpy(dm_mad, mad_wc->recv_buf.mad, sizeof *dm_mad);
    dm_mad->mad_hdr.method = IB_MGMT_METHOD_GET_RESP;
    dm_mad->mad_hdr.status = 0;

    switch (mad_wc->recv_buf.mad->mad_hdr.method) {
    case IB_MGMT_METHOD_GET:
        srpt_mgmt_method_get(sport, mad_wc->recv_buf.mad, dm_mad);
        break;
    case IB_MGMT_METHOD_SET:
        dm_mad->mad_hdr.status =
            __constant_cpu_to_be16(DM_MAD_STATUS_UNSUP_METHOD_ATTR);
        break;
    default:
        dm_mad->mad_hdr.status =
            __constant_cpu_to_be16(DM_MAD_STATUS_UNSUP_METHOD);
        break;
    }

    if (!ib_post_send_mad(rsp, NULL)) {
        ib_free_recv_mad(mad_wc);
        /* will destroy_ah & free_send_mad in send completion */
        return;
    }

    ib_free_send_mad(rsp);

err_rsp:
    ib_destroy_ah(ah);
err:
    ib_free_recv_mad(mad_wc);
}

static int srpt_refresh_port(struct srpt_port *sport)
{
    struct ib_mad_reg_req reg_req;
    struct ib_port_modify port_modify;
    struct ib_port_attr port_attr;
    int ret;

    memset(&port_modify, 0, sizeof port_modify);
    port_modify.set_port_cap_mask = IB_PORT_DEVICE_MGMT_SUP;
    port_modify.clr_port_cap_mask = 0;

    ret = ib_modify_port(sport->sdev->device, sport->port, 0, &port_modify);
    if (ret)
        goto err_mod_port;

    ret = ib_query_port(sport->sdev->device, sport->port, &port_attr);
    if (ret)
        goto err_query_port;

    sport->sm_lid = port_attr.sm_lid;
    sport->lid = port_attr.lid;

    ret = ib_query_gid(sport->sdev->device, sport->port, 0, &sport->gid);
    if (ret)
        goto err_query_port;

    if (!sport->mad_agent) {
        memset(&reg_req, 0, sizeof reg_req);
        reg_req.mgmt_class = IB_MGMT_CLASS_DEVICE_MGMT;
        reg_req.mgmt_class_version = IB_MGMT_BASE_VERSION;
        set_bit(IB_MGMT_METHOD_GET, reg_req.method_mask);
        set_bit(IB_MGMT_METHOD_SET, reg_req.method_mask);

        sport->mad_agent = ib_register_mad_agent(sport->sdev->device,
                             sport->port,
                             IB_QPT_GSI,
                             &reg_req, 0,
                             srpt_mad_send_handler,
                             srpt_mad_recv_handler,
                             sport);
        if (IS_ERR(sport->mad_agent)) {
            ret = PTR_ERR(sport->mad_agent);
            sport->mad_agent = NULL;
            goto err_query_port;
        }
    }

    return 0;

err_query_port:

    port_modify.set_port_cap_mask = 0;
    port_modify.clr_port_cap_mask = IB_PORT_DEVICE_MGMT_SUP;
    ib_modify_port(sport->sdev->device, sport->port, 0, &port_modify);

err_mod_port:

    return ret;
}

static void srpt_unregister_mad_agent(struct srpt_device *sdev)
{
    struct ib_port_modify port_modify = {
        .clr_port_cap_mask = IB_PORT_DEVICE_MGMT_SUP,
    };
    struct srpt_port *sport;
    int i;

    for (i = 1; i <= sdev->device->phys_port_cnt; i++) {
        sport = &sdev->port[i - 1];
        WARN_ON(sport->port != i);
        if (ib_modify_port(sdev->device, i, 0, &port_modify) < 0)
            printk(KERN_ERR "disabling MAD processing failed.\n");
        if (sport->mad_agent) {
            ib_unregister_mad_agent(sport->mad_agent);
            sport->mad_agent = NULL;
        }
    }
}

static struct srpt_ioctx *srpt_alloc_ioctx(struct srpt_device *sdev,
                       int ioctx_size, int dma_size,
                       enum dma_data_direction dir)
{
    struct srpt_ioctx *ioctx;

    ioctx = kmalloc(ioctx_size, GFP_KERNEL);
    if (!ioctx)
        goto err;

    ioctx->buf = kmalloc(dma_size, GFP_KERNEL);
    if (!ioctx->buf)
        goto err_free_ioctx;

    ioctx->dma = ib_dma_map_single(sdev->device, ioctx->buf, dma_size, dir);
    if (ib_dma_mapping_error(sdev->device, ioctx->dma))
        goto err_free_buf;

    return ioctx;

err_free_buf:
    kfree(ioctx->buf);
err_free_ioctx:
    kfree(ioctx);
err:
    return NULL;
}

static void srpt_free_ioctx(struct srpt_device *sdev, struct srpt_ioctx *ioctx,
                int dma_size, enum dma_data_direction dir)
{
    if (!ioctx)
        return;

    ib_dma_unmap_single(sdev->device, ioctx->dma, dma_size, dir);
    kfree(ioctx->buf);
    kfree(ioctx);
}

static struct srpt_ioctx **srpt_alloc_ioctx_ring(struct srpt_device *sdev,
                int ring_size, int ioctx_size,
                int dma_size, enum dma_data_direction dir)
{
    struct srpt_ioctx **ring;
    int i;

    WARN_ON(ioctx_size != sizeof(struct srpt_recv_ioctx)
        && ioctx_size != sizeof(struct srpt_send_ioctx));

    ring = kmalloc(ring_size * sizeof(ring[0]), GFP_KERNEL);
    if (!ring)
        goto out;
    for (i = 0; i < ring_size; ++i) {
        ring[i] = srpt_alloc_ioctx(sdev, ioctx_size, dma_size, dir);
        if (!ring[i])
            goto err;
        ring[i]->index = i;
    }
    goto out;

err:
    while (--i >= 0)
        srpt_free_ioctx(sdev, ring[i], dma_size, dir);
    kfree(ring);
    ring = NULL;
out:
    return ring;
}

static void srpt_free_ioctx_ring(struct srpt_ioctx **ioctx_ring,
                 struct srpt_device *sdev, int ring_size,
                 int dma_size, enum dma_data_direction dir)
{
    int i;

    for (i = 0; i < ring_size; ++i)
        srpt_free_ioctx(sdev, ioctx_ring[i], dma_size, dir);
    kfree(ioctx_ring);
}

static enum srpt_command_state srpt_get_cmd_state(struct srpt_send_ioctx *ioctx)
{
    enum srpt_command_state state;
    unsigned long flags;

    BUG_ON(!ioctx);

    spin_lock_irqsave(&ioctx->spinlock, flags);
    state = ioctx->state;
    spin_unlock_irqrestore(&ioctx->spinlock, flags);
    return state;
}

static enum srpt_command_state srpt_set_cmd_state(struct srpt_send_ioctx *ioctx,
                          enum srpt_command_state new)
{
    enum srpt_command_state previous;
    unsigned long flags;

    BUG_ON(!ioctx);

    spin_lock_irqsave(&ioctx->spinlock, flags);
    previous = ioctx->state;
    if (previous != SRPT_STATE_DONE)
        ioctx->state = new;
    spin_unlock_irqrestore(&ioctx->spinlock, flags);

    return previous;
}

static bool srpt_test_and_set_cmd_state(struct srpt_send_ioctx *ioctx,
                    enum srpt_command_state old,
                    enum srpt_command_state new)
{
    enum srpt_command_state previous;
    unsigned long flags;

    WARN_ON(!ioctx);
    WARN_ON(old == SRPT_STATE_DONE);
    WARN_ON(new == SRPT_STATE_NEW);

    spin_lock_irqsave(&ioctx->spinlock, flags);
    previous = ioctx->state;
    if (previous == old)
        ioctx->state = new;
    spin_unlock_irqrestore(&ioctx->spinlock, flags);
    return previous == old;
}

static int srpt_post_recv(struct srpt_device *sdev,
              struct srpt_recv_ioctx *ioctx)
{
    struct ib_sge list;
    struct ib_recv_wr wr, *bad_wr;

    BUG_ON(!sdev);
    wr.wr_id = encode_wr_id(SRPT_RECV, ioctx->ioctx.index);

    list.addr = ioctx->ioctx.dma;
    list.length = srp_max_req_size;
    list.lkey = sdev->mr->lkey;

    wr.next = NULL;
    wr.sg_list = &list;
    wr.num_sge = 1;

    return ib_post_srq_recv(sdev->srq, &wr, &bad_wr);
}

static int srpt_post_send(struct srpt_rdma_ch *ch,
              struct srpt_send_ioctx *ioctx, int len)
{
    struct ib_sge list;
    struct ib_send_wr wr, *bad_wr;
    struct srpt_device *sdev = ch->sport->sdev;
    int ret;

    atomic_inc(&ch->req_lim);

    ret = -ENOMEM;
    if (unlikely(atomic_dec_return(&ch->sq_wr_avail) < 0)) {
        printk(KERN_WARNING "IB send queue full (needed 1)\n");
        goto out;
    }

    ib_dma_sync_single_for_device(sdev->device, ioctx->ioctx.dma, len,
                      DMA_TO_DEVICE);

    list.addr = ioctx->ioctx.dma;
    list.length = len;
    list.lkey = sdev->mr->lkey;

    wr.next = NULL;
    wr.wr_id = encode_wr_id(SRPT_SEND, ioctx->ioctx.index);
    wr.sg_list = &list;
    wr.num_sge = 1;
    wr.opcode = IB_WR_SEND;
    wr.send_flags = IB_SEND_SIGNALED;

    ret = ib_post_send(ch->qp, &wr, &bad_wr);

out:
    if (ret < 0) {
        atomic_inc(&ch->sq_wr_avail);
        atomic_dec(&ch->req_lim);
    }
    return ret;
}

static int srpt_get_desc_tbl(struct srpt_send_ioctx *ioctx,
                 struct srp_cmd *srp_cmd,
                 enum dma_data_direction *dir, u64 *data_len)
{
    struct srp_indirect_buf *idb;
    struct srp_direct_buf *db;
    unsigned add_cdb_offset;
    int ret;

    /*
     * The pointer computations below will only be compiled correctly
     * if srp_cmd::add_data is declared as s8*, u8*, s8[] or u8[], so check
     * whether srp_cmd::add_data has been declared as a byte pointer.
     */
    BUILD_BUG_ON(!__same_type(srp_cmd->add_data[0], (s8)0)
             && !__same_type(srp_cmd->add_data[0], (u8)0));

    BUG_ON(!dir);
    BUG_ON(!data_len);

    ret = 0;
    *data_len = 0;

    /*
     * The lower four bits of the buffer format field contain the DATA-IN
     * buffer descriptor format, and the highest four bits contain the
     * DATA-OUT buffer descriptor format.
     */
    *dir = DMA_NONE;
    if (srp_cmd->buf_fmt & 0xf)
        /* DATA-IN: transfer data from target to initiator (read). */
        *dir = DMA_FROM_DEVICE;
    else if (srp_cmd->buf_fmt >> 4)
        /* DATA-OUT: transfer data from initiator to target (write). */
        *dir = DMA_TO_DEVICE;

    /*
     * According to the SRP spec, the lower two bits of the 'ADDITIONAL
     * CDB LENGTH' field are reserved and the size in bytes of this field
     * is four times the value specified in bits 3..7. Hence the "& ~3".
     */
    add_cdb_offset = srp_cmd->add_cdb_len & ~3;
    if (((srp_cmd->buf_fmt & 0xf) == SRP_DATA_DESC_DIRECT) ||
        ((srp_cmd->buf_fmt >> 4) == SRP_DATA_DESC_DIRECT)) {
        ioctx->n_rbuf = 1;
        ioctx->rbufs = &ioctx->single_rbuf;

        db = (struct srp_direct_buf *)(srp_cmd->add_data
                           + add_cdb_offset);
        memcpy(ioctx->rbufs, db, sizeof *db);
        *data_len = be32_to_cpu(db->len);
    } else if (((srp_cmd->buf_fmt & 0xf) == SRP_DATA_DESC_INDIRECT) ||
           ((srp_cmd->buf_fmt >> 4) == SRP_DATA_DESC_INDIRECT)) {
        idb = (struct srp_indirect_buf *)(srp_cmd->add_data
                          + add_cdb_offset);

        ioctx->n_rbuf = be32_to_cpu(idb->table_desc.len) / sizeof *db;

        if (ioctx->n_rbuf >
            (srp_cmd->data_out_desc_cnt + srp_cmd->data_in_desc_cnt)) {
            printk(KERN_ERR "received unsupported SRP_CMD request"
                   " type (%u out + %u in != %u / %zu)\n",
                   srp_cmd->data_out_desc_cnt,
                   srp_cmd->data_in_desc_cnt,
                   be32_to_cpu(idb->table_desc.len),
                   sizeof(*db));
            ioctx->n_rbuf = 0;
            ret = -EINVAL;
            goto out;
        }

        if (ioctx->n_rbuf == 1)
            ioctx->rbufs = &ioctx->single_rbuf;
        else {
            ioctx->rbufs =
                kmalloc(ioctx->n_rbuf * sizeof *db, GFP_ATOMIC);
            if (!ioctx->rbufs) {
                ioctx->n_rbuf = 0;
                ret = -ENOMEM;
                goto out;
            }
        }

        db = idb->desc_list;
        memcpy(ioctx->rbufs, db, ioctx->n_rbuf * sizeof *db);
        *data_len = be32_to_cpu(idb->len);
    }
out:
    return ret;
}

static int srpt_init_ch_qp(struct srpt_rdma_ch *ch, struct ib_qp *qp)
{
    struct ib_qp_attr *attr;
    int ret;

    attr = kzalloc(sizeof *attr, GFP_KERNEL);
    if (!attr)
        return -ENOMEM;

    attr->qp_state = IB_QPS_INIT;
    attr->qp_access_flags = IB_ACCESS_LOCAL_WRITE | IB_ACCESS_REMOTE_READ |
        IB_ACCESS_REMOTE_WRITE;
    attr->port_num = ch->sport->port;
    attr->pkey_index = 0;

    ret = ib_modify_qp(qp, attr,
               IB_QP_STATE | IB_QP_ACCESS_FLAGS | IB_QP_PORT |
               IB_QP_PKEY_INDEX);

    kfree(attr);
    return ret;
}

static int srpt_ch_qp_rtr(struct srpt_rdma_ch *ch, struct ib_qp *qp)
{
    struct ib_qp_attr qp_attr;
    int attr_mask;
    int ret;

    qp_attr.qp_state = IB_QPS_RTR;
    ret = ib_cm_init_qp_attr(ch->cm_id, &qp_attr, &attr_mask);
    if (ret)
        goto out;

    qp_attr.max_dest_rd_atomic = 4;

    ret = ib_modify_qp(qp, &qp_attr, attr_mask);

out:
    return ret;
}

static int srpt_ch_qp_rts(struct srpt_rdma_ch *ch, struct ib_qp *qp)
{
    struct ib_qp_attr qp_attr;
    int attr_mask;
    int ret;

    qp_attr.qp_state = IB_QPS_RTS;
    ret = ib_cm_init_qp_attr(ch->cm_id, &qp_attr, &attr_mask);
    if (ret)
        goto out;

    qp_attr.max_rd_atomic = 4;

    ret = ib_modify_qp(qp, &qp_attr, attr_mask);

out:
    return ret;
}

static int srpt_ch_qp_err(struct srpt_rdma_ch *ch)
{
    struct ib_qp_attr qp_attr;

    qp_attr.qp_state = IB_QPS_ERR;
    return ib_modify_qp(ch->qp, &qp_attr, IB_QP_STATE);
}

static void srpt_unmap_sg_to_ib_sge(struct srpt_rdma_ch *ch,
                    struct srpt_send_ioctx *ioctx)
{
    struct scatterlist *sg;
    enum dma_data_direction dir;

    BUG_ON(!ch);
    BUG_ON(!ioctx);
    BUG_ON(ioctx->n_rdma && !ioctx->rdma_ius);

    while (ioctx->n_rdma)
        kfree(ioctx->rdma_ius[--ioctx->n_rdma].sge);

    kfree(ioctx->rdma_ius);
    ioctx->rdma_ius = NULL;

    if (ioctx->mapped_sg_count) {
        sg = ioctx->sg;
        WARN_ON(!sg);
        dir = ioctx->cmd.data_direction;
        BUG_ON(dir == DMA_NONE);
        ib_dma_unmap_sg(ch->sport->sdev->device, sg, ioctx->sg_cnt,
                opposite_dma_dir(dir));
        ioctx->mapped_sg_count = 0;
    }
}

static int srpt_map_sg_to_ib_sge(struct srpt_rdma_ch *ch,
                 struct srpt_send_ioctx *ioctx)
{
    struct se_cmd *cmd;
    struct scatterlist *sg, *sg_orig;
    int sg_cnt;
    enum dma_data_direction dir;
    struct rdma_iu *riu;
    struct srp_direct_buf *db;
    dma_addr_t dma_addr;
    struct ib_sge *sge;
    u64 raddr;
    u32 rsize;
    u32 tsize;
    u32 dma_len;
    int count, nrdma;
    int i, j, k;

    BUG_ON(!ch);
    BUG_ON(!ioctx);
    cmd = &ioctx->cmd;
    dir = cmd->data_direction;
    BUG_ON(dir == DMA_NONE);

    ioctx->sg = sg = sg_orig = cmd->t_data_sg;
    ioctx->sg_cnt = sg_cnt = cmd->t_data_nents;

    count = ib_dma_map_sg(ch->sport->sdev->device, sg, sg_cnt,
                  opposite_dma_dir(dir));
    if (unlikely(!count))
        return -EAGAIN;

    ioctx->mapped_sg_count = count;

    if (ioctx->rdma_ius && ioctx->n_rdma_ius)
        nrdma = ioctx->n_rdma_ius;
    else {
        nrdma = (count + SRPT_DEF_SG_PER_WQE - 1) / SRPT_DEF_SG_PER_WQE
            + ioctx->n_rbuf;

        ioctx->rdma_ius = kzalloc(nrdma * sizeof *riu, GFP_KERNEL);
        if (!ioctx->rdma_ius)
            goto free_mem;

        ioctx->n_rdma_ius = nrdma;
    }

    db = ioctx->rbufs;
    tsize = cmd->data_length;
    dma_len = sg_dma_len(&sg[0]);
    riu = ioctx->rdma_ius;

    /*
     * For each remote desc - calculate the #ib_sge.
     * If #ib_sge < SRPT_DEF_SG_PER_WQE per rdma operation then
     *      each remote desc rdma_iu is required a rdma wr;
     * else
     *      we need to allocate extra rdma_iu to carry extra #ib_sge in
     *      another rdma wr
     */
    for (i = 0, j = 0;
         j < count && i < ioctx->n_rbuf && tsize > 0; ++i, ++riu, ++db) {
        rsize = be32_to_cpu(db->len);
        raddr = be64_to_cpu(db->va);
        riu->raddr = raddr;
        riu->rkey = be32_to_cpu(db->key);
        riu->sge_cnt = 0;

        /* calculate how many sge required for this remote_buf */
        while (rsize > 0 && tsize > 0) {

            if (rsize >= dma_len) {
                tsize -= dma_len;
                rsize -= dma_len;
                raddr += dma_len;

                if (tsize > 0) {
                    ++j;
                    if (j < count) {
                        sg = sg_next(sg);
                        dma_len = sg_dma_len(sg);
                    }
                }
            } else {
                tsize -= rsize;
                dma_len -= rsize;
                rsize = 0;
            }

            ++riu->sge_cnt;

            if (rsize > 0 && riu->sge_cnt == SRPT_DEF_SG_PER_WQE) {
                ++ioctx->n_rdma;
                riu->sge =
                    kmalloc(riu->sge_cnt * sizeof *riu->sge,
                        GFP_KERNEL);
                if (!riu->sge)
                    goto free_mem;

                ++riu;
                riu->sge_cnt = 0;
                riu->raddr = raddr;
                riu->rkey = be32_to_cpu(db->key);
            }
        }

        ++ioctx->n_rdma;
        riu->sge = kmalloc(riu->sge_cnt * sizeof *riu->sge,
                   GFP_KERNEL);
        if (!riu->sge)
            goto free_mem;
    }

    db = ioctx->rbufs;
    tsize = cmd->data_length;
    riu = ioctx->rdma_ius;
    sg = sg_orig;
    dma_len = sg_dma_len(&sg[0]);
    dma_addr = sg_dma_address(&sg[0]);

    /* this second loop is really mapped sg_addres to rdma_iu->ib_sge */
    for (i = 0, j = 0;
         j < count && i < ioctx->n_rbuf && tsize > 0; ++i, ++riu, ++db) {
        rsize = be32_to_cpu(db->len);
        sge = riu->sge;
        k = 0;

        while (rsize > 0 && tsize > 0) {
            sge->addr = dma_addr;
            sge->lkey = ch->sport->sdev->mr->lkey;

            if (rsize >= dma_len) {
                sge->length =
                    (tsize < dma_len) ? tsize : dma_len;
                tsize -= dma_len;
                rsize -= dma_len;

                if (tsize > 0) {
                    ++j;
                    if (j < count) {
                        sg = sg_next(sg);
                        dma_len = sg_dma_len(sg);
                        dma_addr = sg_dma_address(sg);
                    }
                }
            } else {
                sge->length = (tsize < rsize) ? tsize : rsize;
                tsize -= rsize;
                dma_len -= rsize;
                dma_addr += rsize;
                rsize = 0;
            }

            ++k;
            if (k == riu->sge_cnt && rsize > 0 && tsize > 0) {
                ++riu;
                sge = riu->sge;
                k = 0;
            } else if (rsize > 0 && tsize > 0)
                ++sge;
        }
    }

    return 0;

free_mem:
    srpt_unmap_sg_to_ib_sge(ch, ioctx);

    return -ENOMEM;
}

static struct srpt_send_ioctx *srpt_get_send_ioctx(struct srpt_rdma_ch *ch)
{
    struct srpt_send_ioctx *ioctx;
    unsigned long flags;

    BUG_ON(!ch);

    ioctx = NULL;
    spin_lock_irqsave(&ch->spinlock, flags);
    if (!list_empty(&ch->free_list)) {
        ioctx = list_first_entry(&ch->free_list,
                     struct srpt_send_ioctx, free_list);
        list_del(&ioctx->free_list);
    }
    spin_unlock_irqrestore(&ch->spinlock, flags);

    if (!ioctx)
        return ioctx;

    BUG_ON(ioctx->ch != ch);
    kref_init(&ioctx->kref);
    spin_lock_init(&ioctx->spinlock);
    ioctx->state = SRPT_STATE_NEW;
    ioctx->n_rbuf = 0;
    ioctx->rbufs = NULL;
    ioctx->n_rdma = 0;
    ioctx->n_rdma_ius = 0;
    ioctx->rdma_ius = NULL;
    ioctx->mapped_sg_count = 0;
    init_completion(&ioctx->tx_done);
    ioctx->queue_status_only = false;
    /*
     * transport_init_se_cmd() does not initialize all fields, so do it
     * here.
     */
    memset(&ioctx->cmd, 0, sizeof(ioctx->cmd));
    memset(&ioctx->sense_data, 0, sizeof(ioctx->sense_data));

    return ioctx;
}

static void srpt_put_send_ioctx(struct srpt_send_ioctx *ioctx)
{
    struct srpt_rdma_ch *ch;
    unsigned long flags;

    BUG_ON(!ioctx);
    ch = ioctx->ch;
    BUG_ON(!ch);

    WARN_ON(srpt_get_cmd_state(ioctx) != SRPT_STATE_DONE);

    srpt_unmap_sg_to_ib_sge(ioctx->ch, ioctx);
    transport_generic_free_cmd(&ioctx->cmd, 0);

    if (ioctx->n_rbuf > 1) {
        kfree(ioctx->rbufs);
        ioctx->rbufs = NULL;
        ioctx->n_rbuf = 0;
    }

    spin_lock_irqsave(&ch->spinlock, flags);
    list_add(&ioctx->free_list, &ch->free_list);
    spin_unlock_irqrestore(&ch->spinlock, flags);
}

static void srpt_put_send_ioctx_kref(struct kref *kref)
{
    srpt_put_send_ioctx(container_of(kref, struct srpt_send_ioctx, kref));
}

static int srpt_abort_cmd(struct srpt_send_ioctx *ioctx)
{
    enum srpt_command_state state;
    unsigned long flags;

    BUG_ON(!ioctx);

    /*
     * If the command is in a state where the target core is waiting for
     * the ib_srpt driver, change the state to the next state. Changing
     * the state of the command from SRPT_STATE_NEED_DATA to
     * SRPT_STATE_DATA_IN ensures that srpt_xmit_response() will call this
     * function a second time.
     */

    spin_lock_irqsave(&ioctx->spinlock, flags);
    state = ioctx->state;
    switch (state) {
    case SRPT_STATE_NEED_DATA:
        ioctx->state = SRPT_STATE_DATA_IN;
        break;
    case SRPT_STATE_DATA_IN:
    case SRPT_STATE_CMD_RSP_SENT:
    case SRPT_STATE_MGMT_RSP_SENT:
        ioctx->state = SRPT_STATE_DONE;
        break;
    default:
        break;
    }
    spin_unlock_irqrestore(&ioctx->spinlock, flags);

    if (state == SRPT_STATE_DONE)
        goto out;

    pr_debug("Aborting cmd with state %d and tag %lld\n", state,
         ioctx->tag);

    switch (state) {
    case SRPT_STATE_NEW:
    case SRPT_STATE_DATA_IN:
    case SRPT_STATE_MGMT:
        /*
         * Do nothing - defer abort processing until
         * srpt_queue_response() is invoked.
         */
        WARN_ON(!transport_check_aborted_status(&ioctx->cmd, false));
        break;
    case SRPT_STATE_NEED_DATA:
        /* DMA_TO_DEVICE (write) - RDMA read error. */

        /* XXX(hch): this is a horrible layering violation.. */
        spin_lock_irqsave(&ioctx->cmd.t_state_lock, flags);
        ioctx->cmd.transport_state |= CMD_T_LUN_STOP;
        ioctx->cmd.transport_state &= ~CMD_T_ACTIVE;
        spin_unlock_irqrestore(&ioctx->cmd.t_state_lock, flags);

        complete(&ioctx->cmd.transport_lun_stop_comp);
        break;
    case SRPT_STATE_CMD_RSP_SENT:
        /*
         * SRP_RSP sending failed or the SRP_RSP send completion has
         * not been received in time.
         */
        srpt_unmap_sg_to_ib_sge(ioctx->ch, ioctx);
        spin_lock_irqsave(&ioctx->cmd.t_state_lock, flags);
        ioctx->cmd.transport_state |= CMD_T_LUN_STOP;
        spin_unlock_irqrestore(&ioctx->cmd.t_state_lock, flags);
        kref_put(&ioctx->kref, srpt_put_send_ioctx_kref);
        break;
    case SRPT_STATE_MGMT_RSP_SENT:
        srpt_set_cmd_state(ioctx, SRPT_STATE_DONE);
        kref_put(&ioctx->kref, srpt_put_send_ioctx_kref);
        break;
    default:
        WARN_ON("ERROR: unexpected command state");
        break;
    }

out:
    return state;
}

static void srpt_handle_send_err_comp(struct srpt_rdma_ch *ch, u64 wr_id)
{
    struct srpt_send_ioctx *ioctx;
    enum srpt_command_state state;
    struct se_cmd *cmd;
    u32 index;

    atomic_inc(&ch->sq_wr_avail);

    index = idx_from_wr_id(wr_id);
    ioctx = ch->ioctx_ring[index];
    state = srpt_get_cmd_state(ioctx);
    cmd = &ioctx->cmd;

    WARN_ON(state != SRPT_STATE_CMD_RSP_SENT
        && state != SRPT_STATE_MGMT_RSP_SENT
        && state != SRPT_STATE_NEED_DATA
        && state != SRPT_STATE_DONE);

    /* If SRP_RSP sending failed, undo the ch->req_lim change. */
    if (state == SRPT_STATE_CMD_RSP_SENT
        || state == SRPT_STATE_MGMT_RSP_SENT)
        atomic_dec(&ch->req_lim);

    srpt_abort_cmd(ioctx);
}

static void srpt_handle_send_comp(struct srpt_rdma_ch *ch,
                  struct srpt_send_ioctx *ioctx)
{
    enum srpt_command_state state;

    atomic_inc(&ch->sq_wr_avail);

    state = srpt_set_cmd_state(ioctx, SRPT_STATE_DONE);

    if (WARN_ON(state != SRPT_STATE_CMD_RSP_SENT
            && state != SRPT_STATE_MGMT_RSP_SENT
            && state != SRPT_STATE_DONE))
        pr_debug("state = %d\n", state);

    if (state != SRPT_STATE_DONE)
        kref_put(&ioctx->kref, srpt_put_send_ioctx_kref);
    else
        printk(KERN_ERR "IB completion has been received too late for"
               " wr_id = %u.\n", ioctx->ioctx.index);
}

static void srpt_handle_rdma_comp(struct srpt_rdma_ch *ch,
                  struct srpt_send_ioctx *ioctx,
                  enum srpt_opcode opcode)
{
    WARN_ON(ioctx->n_rdma <= 0);
    atomic_add(ioctx->n_rdma, &ch->sq_wr_avail);

    if (opcode == SRPT_RDMA_READ_LAST) {
        if (srpt_test_and_set_cmd_state(ioctx, SRPT_STATE_NEED_DATA,
                        SRPT_STATE_DATA_IN))
            target_execute_cmd(&ioctx->cmd);
        else
            printk(KERN_ERR "%s[%d]: wrong state = %d\n", __func__,
                   __LINE__, srpt_get_cmd_state(ioctx));
    } else if (opcode == SRPT_RDMA_ABORT) {
        ioctx->rdma_aborted = true;
    } else {
        WARN(true, "unexpected opcode %d\n", opcode);
    }
}

static void srpt_handle_rdma_err_comp(struct srpt_rdma_ch *ch,
                      struct srpt_send_ioctx *ioctx,
                      enum srpt_opcode opcode)
{
    struct se_cmd *cmd;
    enum srpt_command_state state;
    unsigned long flags;

    cmd = &ioctx->cmd;
    state = srpt_get_cmd_state(ioctx);
    switch (opcode) {
    case SRPT_RDMA_READ_LAST:
        if (ioctx->n_rdma <= 0) {
            printk(KERN_ERR "Received invalid RDMA read"
                   " error completion with idx %d\n",
                   ioctx->ioctx.index);
            break;
        }
        atomic_add(ioctx->n_rdma, &ch->sq_wr_avail);
        if (state == SRPT_STATE_NEED_DATA)
            srpt_abort_cmd(ioctx);
        else
            printk(KERN_ERR "%s[%d]: wrong state = %d\n",
                   __func__, __LINE__, state);
        break;
    case SRPT_RDMA_WRITE_LAST:
        spin_lock_irqsave(&ioctx->cmd.t_state_lock, flags);
        ioctx->cmd.transport_state |= CMD_T_LUN_STOP;
        spin_unlock_irqrestore(&ioctx->cmd.t_state_lock, flags);
        break;
    default:
        printk(KERN_ERR "%s[%d]: opcode = %u\n", __func__,
               __LINE__, opcode);
        break;
    }
}

static int srpt_build_cmd_rsp(struct srpt_rdma_ch *ch,
                  struct srpt_send_ioctx *ioctx, u64 tag,
                  int status)
{
    struct srp_rsp *srp_rsp;
    const u8 *sense_data;
    int sense_data_len, max_sense_len;

    /*
     * The lowest bit of all SAM-3 status codes is zero (see also
     * paragraph 5.3 in SAM-3).
     */
    WARN_ON(status & 1);

    srp_rsp = ioctx->ioctx.buf;
    BUG_ON(!srp_rsp);

    sense_data = ioctx->sense_data;
    sense_data_len = ioctx->cmd.scsi_sense_length;
    WARN_ON(sense_data_len > sizeof(ioctx->sense_data));

    memset(srp_rsp, 0, sizeof *srp_rsp);
    srp_rsp->opcode = SRP_RSP;
    srp_rsp->req_lim_delta =
        __constant_cpu_to_be32(1 + atomic_xchg(&ch->req_lim_delta, 0));
    srp_rsp->tag = tag;
    srp_rsp->status = status;

    if (sense_data_len) {
        BUILD_BUG_ON(MIN_MAX_RSP_SIZE <= sizeof(*srp_rsp));
        max_sense_len = ch->max_ti_iu_len - sizeof(*srp_rsp);
        if (sense_data_len > max_sense_len) {
            printk(KERN_WARNING "truncated sense data from %d to %d"
                   " bytes\n", sense_data_len, max_sense_len);
            sense_data_len = max_sense_len;
        }

        srp_rsp->flags |= SRP_RSP_FLAG_SNSVALID;
        srp_rsp->sense_data_len = cpu_to_be32(sense_data_len);
        memcpy(srp_rsp + 1, sense_data, sense_data_len);
    }

    return sizeof(*srp_rsp) + sense_data_len;
}

static int srpt_build_tskmgmt_rsp(struct srpt_rdma_ch *ch,
                  struct srpt_send_ioctx *ioctx,
                  u8 rsp_code, u64 tag)
{
    struct srp_rsp *srp_rsp;
    int resp_data_len;
    int resp_len;

    resp_data_len = (rsp_code == SRP_TSK_MGMT_SUCCESS) ? 0 : 4;
    resp_len = sizeof(*srp_rsp) + resp_data_len;

    srp_rsp = ioctx->ioctx.buf;
    BUG_ON(!srp_rsp);
    memset(srp_rsp, 0, sizeof *srp_rsp);

    srp_rsp->opcode = SRP_RSP;
    srp_rsp->req_lim_delta = __constant_cpu_to_be32(1
                    + atomic_xchg(&ch->req_lim_delta, 0));
    srp_rsp->tag = tag;

    if (rsp_code != SRP_TSK_MGMT_SUCCESS) {
        srp_rsp->flags |= SRP_RSP_FLAG_RSPVALID;
        srp_rsp->resp_data_len = cpu_to_be32(resp_data_len);
        srp_rsp->data[3] = rsp_code;
    }

    return resp_len;
}

#define NO_SUCH_LUN ((uint64_t)-1LL)

/*
 * SCSI LUN addressing method. See also SAM-2 and the section about
 * eight byte LUNs.
 */
enum scsi_lun_addr_method {
    SCSI_LUN_ADDR_METHOD_PERIPHERAL   = 0,
    SCSI_LUN_ADDR_METHOD_FLAT         = 1,
    SCSI_LUN_ADDR_METHOD_LUN          = 2,
    SCSI_LUN_ADDR_METHOD_EXTENDED_LUN = 3,
};

/*
 * srpt_unpack_lun() - Convert from network LUN to linear LUN.
 *
 * Convert an 2-byte, 4-byte, 6-byte or 8-byte LUN structure in network byte
 * order (big endian) to a linear LUN. Supports three LUN addressing methods:
 * peripheral, flat and logical unit. See also SAM-2, section 4.9.4 (page 40).
 */
static uint64_t srpt_unpack_lun(const uint8_t *lun, int len)
{
    uint64_t res = NO_SUCH_LUN;
    int addressing_method;

    if (unlikely(len < 2)) {
        printk(KERN_ERR "Illegal LUN length %d, expected 2 bytes or "
               "more", len);
        goto out;
    }

    switch (len) {
    case 8:
        if ((*((__be64 *)lun) &
             __constant_cpu_to_be64(0x0000FFFFFFFFFFFFLL)) != 0)
            goto out_err;
        break;
    case 4:
        if (*((__be16 *)&lun[2]) != 0)
            goto out_err;
        break;
    case 6:
        if (*((__be32 *)&lun[2]) != 0)
            goto out_err;
        break;
    case 2:
        break;
    default:
        goto out_err;
    }

    addressing_method = (*lun) >> 6; /* highest two bits of byte 0 */
    switch (addressing_method) {
    case SCSI_LUN_ADDR_METHOD_PERIPHERAL:
    case SCSI_LUN_ADDR_METHOD_FLAT:
    case SCSI_LUN_ADDR_METHOD_LUN:
        res = *(lun + 1) | (((*lun) & 0x3f) << 8);
        break;

    case SCSI_LUN_ADDR_METHOD_EXTENDED_LUN:
    default:
        printk(KERN_ERR "Unimplemented LUN addressing method %u",
               addressing_method);
        break;
    }

out:
    return res;

out_err:
    printk(KERN_ERR "Support for multi-level LUNs has not yet been"
           " implemented");
    goto out;
}

static int srpt_check_stop_free(struct se_cmd *cmd)
{
    struct srpt_send_ioctx *ioctx;

    ioctx = container_of(cmd, struct srpt_send_ioctx, cmd);
    return kref_put(&ioctx->kref, srpt_put_send_ioctx_kref);
}

static int srpt_handle_cmd(struct srpt_rdma_ch *ch,
               struct srpt_recv_ioctx *recv_ioctx,
               struct srpt_send_ioctx *send_ioctx)
{
    struct se_cmd *cmd;
    struct srp_cmd *srp_cmd;
    uint64_t unpacked_lun;
    u64 data_len;
    enum dma_data_direction dir;
    int ret;

    BUG_ON(!send_ioctx);

    srp_cmd = recv_ioctx->ioctx.buf;
    kref_get(&send_ioctx->kref);
    cmd = &send_ioctx->cmd;
    send_ioctx->tag = srp_cmd->tag;

    switch (srp_cmd->task_attr) {
    case SRP_CMD_SIMPLE_Q:
        cmd->sam_task_attr = MSG_SIMPLE_TAG;
        break;
    case SRP_CMD_ORDERED_Q:
    default:
        cmd->sam_task_attr = MSG_ORDERED_TAG;
        break;
    case SRP_CMD_HEAD_OF_Q:
        cmd->sam_task_attr = MSG_HEAD_TAG;
        break;
    case SRP_CMD_ACA:
        cmd->sam_task_attr = MSG_ACA_TAG;
        break;
    }

    ret = srpt_get_desc_tbl(send_ioctx, srp_cmd, &dir, &data_len);
    if (ret) {
        printk(KERN_ERR "0x%llx: parsing SRP descriptor table failed.\n",
               srp_cmd->tag);
        cmd->se_cmd_flags |= SCF_SCSI_CDB_EXCEPTION;
        cmd->scsi_sense_reason = TCM_INVALID_CDB_FIELD;
        kref_put(&send_ioctx->kref, srpt_put_send_ioctx_kref);
        goto send_sense;
    }

    cmd->data_length = data_len;
    cmd->data_direction = dir;
    unpacked_lun = srpt_unpack_lun((uint8_t *)&srp_cmd->lun,
                       sizeof(srp_cmd->lun));
    if (transport_lookup_cmd_lun(cmd, unpacked_lun) < 0) {
        kref_put(&send_ioctx->kref, srpt_put_send_ioctx_kref);
        goto send_sense;
    }
    ret = target_setup_cmd_from_cdb(cmd, srp_cmd->cdb);
    if (ret < 0) {
        kref_put(&send_ioctx->kref, srpt_put_send_ioctx_kref);
        if (cmd->se_cmd_flags & SCF_SCSI_RESERVATION_CONFLICT) {
            srpt_queue_status(cmd);
            return 0;
        } else
            goto send_sense;
    }

    transport_handle_cdb_direct(cmd);
    return 0;

send_sense:
    transport_send_check_condition_and_sense(cmd, cmd->scsi_sense_reason,
                         0);
    return -1;
}

static int srpt_rx_mgmt_fn_tag(struct srpt_send_ioctx *ioctx, u64 tag)
{
    struct srpt_device *sdev;
    struct srpt_rdma_ch *ch;
    struct srpt_send_ioctx *target;
    int ret, i;

    ret = -EINVAL;
    ch = ioctx->ch;
    BUG_ON(!ch);
    BUG_ON(!ch->sport);
    sdev = ch->sport->sdev;
    BUG_ON(!sdev);
    spin_lock_irq(&sdev->spinlock);
    for (i = 0; i < ch->rq_size; ++i) {
        target = ch->ioctx_ring[i];
        if (target->cmd.se_lun == ioctx->cmd.se_lun &&
            target->tag == tag &&
            srpt_get_cmd_state(target) != SRPT_STATE_DONE) {
            ret = 0;
            /* now let the target core abort &target->cmd; */
            break;
        }
    }
    spin_unlock_irq(&sdev->spinlock);
    return ret;
}

static int srp_tmr_to_tcm(int fn)
{
    switch (fn) {
    case SRP_TSK_ABORT_TASK:
        return TMR_ABORT_TASK;
    case SRP_TSK_ABORT_TASK_SET:
        return TMR_ABORT_TASK_SET;
    case SRP_TSK_CLEAR_TASK_SET:
        return TMR_CLEAR_TASK_SET;
    case SRP_TSK_LUN_RESET:
        return TMR_LUN_RESET;
    case SRP_TSK_CLEAR_ACA:
        return TMR_CLEAR_ACA;
    default:
        return -1;
    }
}

static void srpt_handle_tsk_mgmt(struct srpt_rdma_ch *ch,
                 struct srpt_recv_ioctx *recv_ioctx,
                 struct srpt_send_ioctx *send_ioctx)
{
    struct srp_tsk_mgmt *srp_tsk;
    struct se_cmd *cmd;
    uint64_t unpacked_lun;
    int tcm_tmr;
    int res;

    BUG_ON(!send_ioctx);

    srp_tsk = recv_ioctx->ioctx.buf;
    cmd = &send_ioctx->cmd;

    pr_debug("recv tsk_mgmt fn %d for task_tag %lld and cmd tag %lld"
         " cm_id %p sess %p\n", srp_tsk->tsk_mgmt_func,
         srp_tsk->task_tag, srp_tsk->tag, ch->cm_id, ch->sess);

    srpt_set_cmd_state(send_ioctx, SRPT_STATE_MGMT);
    send_ioctx->tag = srp_tsk->tag;
    tcm_tmr = srp_tmr_to_tcm(srp_tsk->tsk_mgmt_func);
    if (tcm_tmr < 0) {
        send_ioctx->cmd.se_cmd_flags |= SCF_SCSI_CDB_EXCEPTION;
        send_ioctx->cmd.se_tmr_req->response =
            TMR_TASK_MGMT_FUNCTION_NOT_SUPPORTED;
        goto process_tmr;
    }
    res = core_tmr_alloc_req(cmd, NULL, tcm_tmr, GFP_KERNEL);
    if (res < 0) {
        send_ioctx->cmd.se_cmd_flags |= SCF_SCSI_CDB_EXCEPTION;
        send_ioctx->cmd.se_tmr_req->response = TMR_FUNCTION_REJECTED;
        goto process_tmr;
    }

    unpacked_lun = srpt_unpack_lun((uint8_t *)&srp_tsk->lun,
                       sizeof(srp_tsk->lun));
    res = transport_lookup_tmr_lun(&send_ioctx->cmd, unpacked_lun);
    if (res) {
        pr_debug("rejecting TMR for LUN %lld\n", unpacked_lun);
        send_ioctx->cmd.se_cmd_flags |= SCF_SCSI_CDB_EXCEPTION;
        send_ioctx->cmd.se_tmr_req->response = TMR_LUN_DOES_NOT_EXIST;
        goto process_tmr;
    }

    if (srp_tsk->tsk_mgmt_func == SRP_TSK_ABORT_TASK)
        srpt_rx_mgmt_fn_tag(send_ioctx, srp_tsk->task_tag);

process_tmr:
    kref_get(&send_ioctx->kref);
    if (!(send_ioctx->cmd.se_cmd_flags & SCF_SCSI_CDB_EXCEPTION))
        transport_generic_handle_tmr(&send_ioctx->cmd);
    else
        transport_send_check_condition_and_sense(cmd,
                        cmd->scsi_sense_reason, 0);

}

static void srpt_handle_new_iu(struct srpt_rdma_ch *ch,
                   struct srpt_recv_ioctx *recv_ioctx,
                   struct srpt_send_ioctx *send_ioctx)
{
    struct srp_cmd *srp_cmd;
    enum rdma_ch_state ch_state;

    BUG_ON(!ch);
    BUG_ON(!recv_ioctx);

    ib_dma_sync_single_for_cpu(ch->sport->sdev->device,
                   recv_ioctx->ioctx.dma, srp_max_req_size,
                   DMA_FROM_DEVICE);

    ch_state = srpt_get_ch_state(ch);
    if (unlikely(ch_state == CH_CONNECTING)) {
        list_add_tail(&recv_ioctx->wait_list, &ch->cmd_wait_list);
        goto out;
    }

    if (unlikely(ch_state != CH_LIVE))
        goto out;

    srp_cmd = recv_ioctx->ioctx.buf;
    if (srp_cmd->opcode == SRP_CMD || srp_cmd->opcode == SRP_TSK_MGMT) {
        if (!send_ioctx)
            send_ioctx = srpt_get_send_ioctx(ch);
        if (unlikely(!send_ioctx)) {
            list_add_tail(&recv_ioctx->wait_list,
                      &ch->cmd_wait_list);
            goto out;
        }
    }

    transport_init_se_cmd(&send_ioctx->cmd, &srpt_target->tf_ops, ch->sess,
                  0, DMA_NONE, MSG_SIMPLE_TAG,
                  send_ioctx->sense_data);

    switch (srp_cmd->opcode) {
    case SRP_CMD:
        srpt_handle_cmd(ch, recv_ioctx, send_ioctx);
        break;
    case SRP_TSK_MGMT:
        srpt_handle_tsk_mgmt(ch, recv_ioctx, send_ioctx);
        break;
    case SRP_I_LOGOUT:
        printk(KERN_ERR "Not yet implemented: SRP_I_LOGOUT\n");
        break;
    case SRP_CRED_RSP:
        pr_debug("received SRP_CRED_RSP\n");
        break;
    case SRP_AER_RSP:
        pr_debug("received SRP_AER_RSP\n");
        break;
    case SRP_RSP:
        printk(KERN_ERR "Received SRP_RSP\n");
        break;
    default:
        printk(KERN_ERR "received IU with unknown opcode 0x%x\n",
               srp_cmd->opcode);
        break;
    }

    srpt_post_recv(ch->sport->sdev, recv_ioctx);
out:
    return;
}

static void srpt_process_rcv_completion(struct ib_cq *cq,
                    struct srpt_rdma_ch *ch,
                    struct ib_wc *wc)
{
    struct srpt_device *sdev = ch->sport->sdev;
    struct srpt_recv_ioctx *ioctx;
    u32 index;

    index = idx_from_wr_id(wc->wr_id);
    if (wc->status == IB_WC_SUCCESS) {
        int req_lim;

        req_lim = atomic_dec_return(&ch->req_lim);
        if (unlikely(req_lim < 0))
            printk(KERN_ERR "req_lim = %d < 0\n", req_lim);
        ioctx = sdev->ioctx_ring[index];
        srpt_handle_new_iu(ch, ioctx, NULL);
    } else {
        printk(KERN_INFO "receiving failed for idx %u with status %d\n",
               index, wc->status);
    }
}

static void srpt_process_send_completion(struct ib_cq *cq,
                     struct srpt_rdma_ch *ch,
                     struct ib_wc *wc)
{
    struct srpt_send_ioctx *send_ioctx;
    uint32_t index;
    enum srpt_opcode opcode;

    index = idx_from_wr_id(wc->wr_id);
    opcode = opcode_from_wr_id(wc->wr_id);
    send_ioctx = ch->ioctx_ring[index];
    if (wc->status == IB_WC_SUCCESS) {
        if (opcode == SRPT_SEND)
            srpt_handle_send_comp(ch, send_ioctx);
        else {
            WARN_ON(opcode != SRPT_RDMA_ABORT &&
                wc->opcode != IB_WC_RDMA_READ);
            srpt_handle_rdma_comp(ch, send_ioctx, opcode);
        }
    } else {
        if (opcode == SRPT_SEND) {
            printk(KERN_INFO "sending response for idx %u failed"
                   " with status %d\n", index, wc->status);
            srpt_handle_send_err_comp(ch, wc->wr_id);
        } else if (opcode != SRPT_RDMA_MID) {
            printk(KERN_INFO "RDMA t %d for idx %u failed with"
                " status %d", opcode, index, wc->status);
            srpt_handle_rdma_err_comp(ch, send_ioctx, opcode);
        }
    }

    while (unlikely(opcode == SRPT_SEND
            && !list_empty(&ch->cmd_wait_list)
            && srpt_get_ch_state(ch) == CH_LIVE
            && (send_ioctx = srpt_get_send_ioctx(ch)) != NULL)) {
        struct srpt_recv_ioctx *recv_ioctx;

        recv_ioctx = list_first_entry(&ch->cmd_wait_list,
                          struct srpt_recv_ioctx,
                          wait_list);
        list_del(&recv_ioctx->wait_list);
        srpt_handle_new_iu(ch, recv_ioctx, send_ioctx);
    }
}

static void srpt_process_completion(struct ib_cq *cq, struct srpt_rdma_ch *ch)
{
    struct ib_wc *const wc = ch->wc;
    int i, n;

    WARN_ON(cq != ch->cq);

    ib_req_notify_cq(cq, IB_CQ_NEXT_COMP);
    while ((n = ib_poll_cq(cq, ARRAY_SIZE(ch->wc), wc)) > 0) {
        for (i = 0; i < n; i++) {
            if (opcode_from_wr_id(wc[i].wr_id) == SRPT_RECV)
                srpt_process_rcv_completion(cq, ch, &wc[i]);
            else
                srpt_process_send_completion(cq, ch, &wc[i]);
        }
    }
}

static void srpt_completion(struct ib_cq *cq, void *ctx)
{
    struct srpt_rdma_ch *ch = ctx;

    wake_up_interruptible(&ch->wait_queue);
}

static int srpt_compl_thread(void *arg)
{
    struct srpt_rdma_ch *ch;

    /* Hibernation / freezing of the SRPT kernel thread is not supported. */
    current->flags |= PF_NOFREEZE;

    ch = arg;
    BUG_ON(!ch);
    printk(KERN_INFO "Session %s: kernel thread %s (PID %d) started\n",
           ch->sess_name, ch->thread->comm, current->pid);
    while (!kthread_should_stop()) {
        wait_event_interruptible(ch->wait_queue,
            (srpt_process_completion(ch->cq, ch),
             kthread_should_stop()));
    }
    printk(KERN_INFO "Session %s: kernel thread %s (PID %d) stopped\n",
           ch->sess_name, ch->thread->comm, current->pid);
    return 0;
}

static int srpt_create_ch_ib(struct srpt_rdma_ch *ch)
{
    struct ib_qp_init_attr *qp_init;
    struct srpt_port *sport = ch->sport;
    struct srpt_device *sdev = sport->sdev;
    u32 srp_sq_size = sport->port_attrib.srp_sq_size;
    int ret;

    WARN_ON(ch->rq_size < 1);

    ret = -ENOMEM;
    qp_init = kzalloc(sizeof *qp_init, GFP_KERNEL);
    if (!qp_init)
        goto out;

    ch->cq = ib_create_cq(sdev->device, srpt_completion, NULL, ch,
                  ch->rq_size + srp_sq_size, 0);
    if (IS_ERR(ch->cq)) {
        ret = PTR_ERR(ch->cq);
        printk(KERN_ERR "failed to create CQ cqe= %d ret= %d\n",
               ch->rq_size + srp_sq_size, ret);
        goto out;
    }

    qp_init->qp_context = (void *)ch;
    qp_init->event_handler
        = (void(*)(struct ib_event *, void*))srpt_qp_event;
    qp_init->send_cq = ch->cq;
    qp_init->recv_cq = ch->cq;
    qp_init->srq = sdev->srq;
    qp_init->sq_sig_type = IB_SIGNAL_REQ_WR;
    qp_init->qp_type = IB_QPT_RC;
    qp_init->cap.max_send_wr = srp_sq_size;
    qp_init->cap.max_send_sge = SRPT_DEF_SG_PER_WQE;

    ch->qp = ib_create_qp(sdev->pd, qp_init);
    if (IS_ERR(ch->qp)) {
        ret = PTR_ERR(ch->qp);
        printk(KERN_ERR "failed to create_qp ret= %d\n", ret);
        goto err_destroy_cq;
    }

    atomic_set(&ch->sq_wr_avail, qp_init->cap.max_send_wr);

    pr_debug("%s: max_cqe= %d max_sge= %d sq_size = %d cm_id= %p\n",
         __func__, ch->cq->cqe, qp_init->cap.max_send_sge,
         qp_init->cap.max_send_wr, ch->cm_id);

    ret = srpt_init_ch_qp(ch, ch->qp);
    if (ret)
        goto err_destroy_qp;

    init_waitqueue_head(&ch->wait_queue);

    pr_debug("creating thread for session %s\n", ch->sess_name);

    ch->thread = kthread_run(srpt_compl_thread, ch, "ib_srpt_compl");
    if (IS_ERR(ch->thread)) {
        printk(KERN_ERR "failed to create kernel thread %ld\n",
               PTR_ERR(ch->thread));
        ch->thread = NULL;
        goto err_destroy_qp;
    }

out:
    kfree(qp_init);
    return ret;

err_destroy_qp:
    ib_destroy_qp(ch->qp);
err_destroy_cq:
    ib_destroy_cq(ch->cq);
    goto out;
}

static void srpt_destroy_ch_ib(struct srpt_rdma_ch *ch)
{
    if (ch->thread)
        kthread_stop(ch->thread);

    ib_destroy_qp(ch->qp);
    ib_destroy_cq(ch->cq);
}

static void __srpt_close_ch(struct srpt_rdma_ch *ch)
{
    struct srpt_device *sdev;
    enum rdma_ch_state prev_state;
    unsigned long flags;

    sdev = ch->sport->sdev;

    spin_lock_irqsave(&ch->spinlock, flags);
    prev_state = ch->state;
    switch (prev_state) {
    case CH_CONNECTING:
    case CH_LIVE:
        ch->state = CH_DISCONNECTING;
        break;
    default:
        break;
    }
    spin_unlock_irqrestore(&ch->spinlock, flags);

    switch (prev_state) {
    case CH_CONNECTING:
        ib_send_cm_rej(ch->cm_id, IB_CM_REJ_NO_RESOURCES, NULL, 0,
                   NULL, 0);
        /* fall through */
    case CH_LIVE:
        if (ib_send_cm_dreq(ch->cm_id, NULL, 0) < 0)
            printk(KERN_ERR "sending CM DREQ failed.\n");
        break;
    case CH_DISCONNECTING:
        break;
    case CH_DRAINING:
    case CH_RELEASING:
        break;
    }
}

static void srpt_close_ch(struct srpt_rdma_ch *ch)
{
    struct srpt_device *sdev;

    sdev = ch->sport->sdev;
    spin_lock_irq(&sdev->spinlock);
    __srpt_close_ch(ch);
    spin_unlock_irq(&sdev->spinlock);
}

static void srpt_drain_channel(struct ib_cm_id *cm_id)
{
    struct srpt_device *sdev;
    struct srpt_rdma_ch *ch;
    int ret;
    bool do_reset = false;

    WARN_ON_ONCE(irqs_disabled());

    sdev = cm_id->context;
    BUG_ON(!sdev);
    spin_lock_irq(&sdev->spinlock);
    list_for_each_entry(ch, &sdev->rch_list, list) {
        if (ch->cm_id == cm_id) {
            do_reset = srpt_test_and_set_ch_state(ch,
                    CH_CONNECTING, CH_DRAINING) ||
                   srpt_test_and_set_ch_state(ch,
                    CH_LIVE, CH_DRAINING) ||
                   srpt_test_and_set_ch_state(ch,
                    CH_DISCONNECTING, CH_DRAINING);
            break;
        }
    }
    spin_unlock_irq(&sdev->spinlock);

    if (do_reset) {
        ret = srpt_ch_qp_err(ch);
        if (ret < 0)
            printk(KERN_ERR "Setting queue pair in error state"
                   " failed: %d\n", ret);
    }
}

static struct srpt_rdma_ch *srpt_find_channel(struct srpt_device *sdev,
                          struct ib_cm_id *cm_id)
{
    struct srpt_rdma_ch *ch;
    bool found;

    WARN_ON_ONCE(irqs_disabled());
    BUG_ON(!sdev);

    found = false;
    spin_lock_irq(&sdev->spinlock);
    list_for_each_entry(ch, &sdev->rch_list, list) {
        if (ch->cm_id == cm_id) {
            found = true;
            break;
        }
    }
    spin_unlock_irq(&sdev->spinlock);

    return found ? ch : NULL;
}

static void srpt_release_channel(struct srpt_rdma_ch *ch)
{
    schedule_work(&ch->release_work);
}

static void srpt_release_channel_work(struct work_struct *w)
{
    struct srpt_rdma_ch *ch;
    struct srpt_device *sdev;

    ch = container_of(w, struct srpt_rdma_ch, release_work);
    pr_debug("ch = %p; ch->sess = %p; release_done = %p\n", ch, ch->sess,
         ch->release_done);

    sdev = ch->sport->sdev;
    BUG_ON(!sdev);

    transport_deregister_session_configfs(ch->sess);
    transport_deregister_session(ch->sess);
    ch->sess = NULL;

    srpt_destroy_ch_ib(ch);

    srpt_free_ioctx_ring((struct srpt_ioctx **)ch->ioctx_ring,
                 ch->sport->sdev, ch->rq_size,
                 ch->rsp_size, DMA_TO_DEVICE);

    spin_lock_irq(&sdev->spinlock);
    list_del(&ch->list);
    spin_unlock_irq(&sdev->spinlock);

    ib_destroy_cm_id(ch->cm_id);

    if (ch->release_done)
        complete(ch->release_done);

    wake_up(&sdev->ch_releaseQ);

    kfree(ch);
}

static struct srpt_node_acl *__srpt_lookup_acl(struct srpt_port *sport,
                           u8 i_port_id[16])
{
    struct srpt_node_acl *nacl;

    list_for_each_entry(nacl, &sport->port_acl_list, list)
        if (memcmp(nacl->i_port_id, i_port_id,
               sizeof(nacl->i_port_id)) == 0)
            return nacl;

    return NULL;
}

static struct srpt_node_acl *srpt_lookup_acl(struct srpt_port *sport,
                         u8 i_port_id[16])
{
    struct srpt_node_acl *nacl;

    spin_lock_irq(&sport->port_acl_lock);
    nacl = __srpt_lookup_acl(sport, i_port_id);
    spin_unlock_irq(&sport->port_acl_lock);

    return nacl;
}

static int srpt_cm_req_recv(struct ib_cm_id *cm_id,
                struct ib_cm_req_event_param *param,
                void *private_data)
{
    struct srpt_device *sdev = cm_id->context;
    struct srpt_port *sport = &sdev->port[param->port - 1];
    struct srp_login_req *req;
    struct srp_login_rsp *rsp;
    struct srp_login_rej *rej;
    struct ib_cm_rep_param *rep_param;
    struct srpt_rdma_ch *ch, *tmp_ch;
    struct srpt_node_acl *nacl;
    u32 it_iu_len;
    int i;
    int ret = 0;

    WARN_ON_ONCE(irqs_disabled());

    if (WARN_ON(!sdev || !private_data))
        return -EINVAL;

    req = (struct srp_login_req *)private_data;

    it_iu_len = be32_to_cpu(req->req_it_iu_len);

    printk(KERN_INFO "Received SRP_LOGIN_REQ with i_port_id 0x%llx:0x%llx,"
           " t_port_id 0x%llx:0x%llx and it_iu_len %d on port %d"
           " (guid=0x%llx:0x%llx)\n",
           be64_to_cpu(*(__be64 *)&req->initiator_port_id[0]),
           be64_to_cpu(*(__be64 *)&req->initiator_port_id[8]),
           be64_to_cpu(*(__be64 *)&req->target_port_id[0]),
           be64_to_cpu(*(__be64 *)&req->target_port_id[8]),
           it_iu_len,
           param->port,
           be64_to_cpu(*(__be64 *)&sdev->port[param->port - 1].gid.raw[0]),
           be64_to_cpu(*(__be64 *)&sdev->port[param->port - 1].gid.raw[8]));

    rsp = kzalloc(sizeof *rsp, GFP_KERNEL);
    rej = kzalloc(sizeof *rej, GFP_KERNEL);
    rep_param = kzalloc(sizeof *rep_param, GFP_KERNEL);

    if (!rsp || !rej || !rep_param) {
        ret = -ENOMEM;
        goto out;
    }

    if (it_iu_len > srp_max_req_size || it_iu_len < 64) {
        rej->reason = __constant_cpu_to_be32(
                SRP_LOGIN_REJ_REQ_IT_IU_LENGTH_TOO_LARGE);
        ret = -EINVAL;
        printk(KERN_ERR "rejected SRP_LOGIN_REQ because its"
               " length (%d bytes) is out of range (%d .. %d)\n",
               it_iu_len, 64, srp_max_req_size);
        goto reject;
    }

    if (!sport->enabled) {
        rej->reason = __constant_cpu_to_be32(
                 SRP_LOGIN_REJ_INSUFFICIENT_RESOURCES);
        ret = -EINVAL;
        printk(KERN_ERR "rejected SRP_LOGIN_REQ because the target port"
               " has not yet been enabled\n");
        goto reject;
    }

    if ((req->req_flags & SRP_MTCH_ACTION) == SRP_MULTICHAN_SINGLE) {
        rsp->rsp_flags = SRP_LOGIN_RSP_MULTICHAN_NO_CHAN;

        spin_lock_irq(&sdev->spinlock);

        list_for_each_entry_safe(ch, tmp_ch, &sdev->rch_list, list) {
            if (!memcmp(ch->i_port_id, req->initiator_port_id, 16)
                && !memcmp(ch->t_port_id, req->target_port_id, 16)
                && param->port == ch->sport->port
                && param->listen_id == ch->sport->sdev->cm_id
                && ch->cm_id) {
                enum rdma_ch_state ch_state;

                ch_state = srpt_get_ch_state(ch);
                if (ch_state != CH_CONNECTING
                    && ch_state != CH_LIVE)
                    continue;

                /* found an existing channel */
                pr_debug("Found existing channel %s"
                     " cm_id= %p state= %d\n",
                     ch->sess_name, ch->cm_id, ch_state);

                __srpt_close_ch(ch);

                rsp->rsp_flags =
                    SRP_LOGIN_RSP_MULTICHAN_TERMINATED;
            }
        }

        spin_unlock_irq(&sdev->spinlock);

    } else
        rsp->rsp_flags = SRP_LOGIN_RSP_MULTICHAN_MAINTAINED;

    if (*(__be64 *)req->target_port_id != cpu_to_be64(srpt_service_guid)
        || *(__be64 *)(req->target_port_id + 8) !=
           cpu_to_be64(srpt_service_guid)) {
        rej->reason = __constant_cpu_to_be32(
                SRP_LOGIN_REJ_UNABLE_ASSOCIATE_CHANNEL);
        ret = -ENOMEM;
        printk(KERN_ERR "rejected SRP_LOGIN_REQ because it"
               " has an invalid target port identifier.\n");
        goto reject;
    }

    ch = kzalloc(sizeof *ch, GFP_KERNEL);
    if (!ch) {
        rej->reason = __constant_cpu_to_be32(
                    SRP_LOGIN_REJ_INSUFFICIENT_RESOURCES);
        printk(KERN_ERR "rejected SRP_LOGIN_REQ because no memory.\n");
        ret = -ENOMEM;
        goto reject;
    }

    INIT_WORK(&ch->release_work, srpt_release_channel_work);
    memcpy(ch->i_port_id, req->initiator_port_id, 16);
    memcpy(ch->t_port_id, req->target_port_id, 16);
    ch->sport = &sdev->port[param->port - 1];
    ch->cm_id = cm_id;
    /*
     * Avoid QUEUE_FULL conditions by limiting the number of buffers used
     * for the SRP protocol to the command queue size.
     */
    ch->rq_size = SRPT_RQ_SIZE;
    spin_lock_init(&ch->spinlock);
    ch->state = CH_CONNECTING;
    INIT_LIST_HEAD(&ch->cmd_wait_list);
    ch->rsp_size = ch->sport->port_attrib.srp_max_rsp_size;

    ch->ioctx_ring = (struct srpt_send_ioctx **)
        srpt_alloc_ioctx_ring(ch->sport->sdev, ch->rq_size,
                      sizeof(*ch->ioctx_ring[0]),
                      ch->rsp_size, DMA_TO_DEVICE);
    if (!ch->ioctx_ring)
        goto free_ch;

    INIT_LIST_HEAD(&ch->free_list);
    for (i = 0; i < ch->rq_size; i++) {
        ch->ioctx_ring[i]->ch = ch;
        list_add_tail(&ch->ioctx_ring[i]->free_list, &ch->free_list);
    }

    ret = srpt_create_ch_ib(ch);
    if (ret) {
        rej->reason = __constant_cpu_to_be32(
                SRP_LOGIN_REJ_INSUFFICIENT_RESOURCES);
        printk(KERN_ERR "rejected SRP_LOGIN_REQ because creating"
               " a new RDMA channel failed.\n");
        goto free_ring;
    }

    ret = srpt_ch_qp_rtr(ch, ch->qp);
    if (ret) {
        rej->reason = __constant_cpu_to_be32(
                SRP_LOGIN_REJ_INSUFFICIENT_RESOURCES);
        printk(KERN_ERR "rejected SRP_LOGIN_REQ because enabling"
               " RTR failed (error code = %d)\n", ret);
        goto destroy_ib;
    }
    /*
     * Use the initator port identifier as the session name.
     */
    snprintf(ch->sess_name, sizeof(ch->sess_name), "0x%016llx%016llx",
            be64_to_cpu(*(__be64 *)ch->i_port_id),
            be64_to_cpu(*(__be64 *)(ch->i_port_id + 8)));

    pr_debug("registering session %s\n", ch->sess_name);

    nacl = srpt_lookup_acl(sport, ch->i_port_id);
    if (!nacl) {
        printk(KERN_INFO "Rejected login because no ACL has been"
               " configured yet for initiator %s.\n", ch->sess_name);
        rej->reason = __constant_cpu_to_be32(
                SRP_LOGIN_REJ_CHANNEL_LIMIT_REACHED);
        goto destroy_ib;
    }

    ch->sess = transport_init_session();
    if (IS_ERR(ch->sess)) {
        rej->reason = __constant_cpu_to_be32(
                SRP_LOGIN_REJ_INSUFFICIENT_RESOURCES);
        pr_debug("Failed to create session\n");
        goto deregister_session;
    }
    ch->sess->se_node_acl = &nacl->nacl;
    transport_register_session(&sport->port_tpg_1, &nacl->nacl, ch->sess, ch);

    pr_debug("Establish connection sess=%p name=%s cm_id=%p\n", ch->sess,
         ch->sess_name, ch->cm_id);

    /* create srp_login_response */
    rsp->opcode = SRP_LOGIN_RSP;
    rsp->tag = req->tag;
    rsp->max_it_iu_len = req->req_it_iu_len;
    rsp->max_ti_iu_len = req->req_it_iu_len;
    ch->max_ti_iu_len = it_iu_len;
    rsp->buf_fmt = __constant_cpu_to_be16(SRP_BUF_FORMAT_DIRECT
                          | SRP_BUF_FORMAT_INDIRECT);
    rsp->req_lim_delta = cpu_to_be32(ch->rq_size);
    atomic_set(&ch->req_lim, ch->rq_size);
    atomic_set(&ch->req_lim_delta, 0);

    /* create cm reply */
    rep_param->qp_num = ch->qp->qp_num;
    rep_param->private_data = (void *)rsp;
    rep_param->private_data_len = sizeof *rsp;
    rep_param->rnr_retry_count = 7;
    rep_param->flow_control = 1;
    rep_param->failover_accepted = 0;
    rep_param->srq = 1;
    rep_param->responder_resources = 4;
    rep_param->initiator_depth = 4;

    ret = ib_send_cm_rep(cm_id, rep_param);
    if (ret) {
        printk(KERN_ERR "sending SRP_LOGIN_REQ response failed"
               " (error code = %d)\n", ret);
        goto release_channel;
    }

    spin_lock_irq(&sdev->spinlock);
    list_add_tail(&ch->list, &sdev->rch_list);
    spin_unlock_irq(&sdev->spinlock);

    goto out;

release_channel:
    srpt_set_ch_state(ch, CH_RELEASING);
    transport_deregister_session_configfs(ch->sess);

deregister_session:
    transport_deregister_session(ch->sess);
    ch->sess = NULL;

destroy_ib:
    srpt_destroy_ch_ib(ch);

free_ring:
    srpt_free_ioctx_ring((struct srpt_ioctx **)ch->ioctx_ring,
                 ch->sport->sdev, ch->rq_size,
                 ch->rsp_size, DMA_TO_DEVICE);
free_ch:
    kfree(ch);

reject:
    rej->opcode = SRP_LOGIN_REJ;
    rej->tag = req->tag;
    rej->buf_fmt = __constant_cpu_to_be16(SRP_BUF_FORMAT_DIRECT
                          | SRP_BUF_FORMAT_INDIRECT);

    ib_send_cm_rej(cm_id, IB_CM_REJ_CONSUMER_DEFINED, NULL, 0,
                 (void *)rej, sizeof *rej);

out:
    kfree(rep_param);
    kfree(rsp);
    kfree(rej);

    return ret;
}

static void srpt_cm_rej_recv(struct ib_cm_id *cm_id)
{
    printk(KERN_INFO "Received IB REJ for cm_id %p.\n", cm_id);
    srpt_drain_channel(cm_id);
}

static void srpt_cm_rtu_recv(struct ib_cm_id *cm_id)
{
    struct srpt_rdma_ch *ch;
    int ret;

    ch = srpt_find_channel(cm_id->context, cm_id);
    BUG_ON(!ch);

    if (srpt_test_and_set_ch_state(ch, CH_CONNECTING, CH_LIVE)) {
        struct srpt_recv_ioctx *ioctx, *ioctx_tmp;

        ret = srpt_ch_qp_rts(ch, ch->qp);

        list_for_each_entry_safe(ioctx, ioctx_tmp, &ch->cmd_wait_list,
                     wait_list) {
            list_del(&ioctx->wait_list);
            srpt_handle_new_iu(ch, ioctx, NULL);
        }
        if (ret)
            srpt_close_ch(ch);
    }
}

static void srpt_cm_timewait_exit(struct ib_cm_id *cm_id)
{
    printk(KERN_INFO "Received IB TimeWait exit for cm_id %p.\n", cm_id);
    srpt_drain_channel(cm_id);
}

static void srpt_cm_rep_error(struct ib_cm_id *cm_id)
{
    printk(KERN_INFO "Received IB REP error for cm_id %p.\n", cm_id);
    srpt_drain_channel(cm_id);
}

static void srpt_cm_dreq_recv(struct ib_cm_id *cm_id)
{
    struct srpt_rdma_ch *ch;
    unsigned long flags;
    bool send_drep = false;

    ch = srpt_find_channel(cm_id->context, cm_id);
    BUG_ON(!ch);

    pr_debug("cm_id= %p ch->state= %d\n", cm_id, srpt_get_ch_state(ch));

    spin_lock_irqsave(&ch->spinlock, flags);
    switch (ch->state) {
    case CH_CONNECTING:
    case CH_LIVE:
        send_drep = true;
        ch->state = CH_DISCONNECTING;
        break;
    case CH_DISCONNECTING:
    case CH_DRAINING:
    case CH_RELEASING:
        WARN(true, "unexpected channel state %d\n", ch->state);
        break;
    }
    spin_unlock_irqrestore(&ch->spinlock, flags);

    if (send_drep) {
        if (ib_send_cm_drep(ch->cm_id, NULL, 0) < 0)
            printk(KERN_ERR "Sending IB DREP failed.\n");
        printk(KERN_INFO "Received DREQ and sent DREP for session %s.\n",
               ch->sess_name);
    }
}

static void srpt_cm_drep_recv(struct ib_cm_id *cm_id)
{
    printk(KERN_INFO "Received InfiniBand DREP message for cm_id %p.\n",
           cm_id);
    srpt_drain_channel(cm_id);
}

static int srpt_cm_handler(struct ib_cm_id *cm_id, struct ib_cm_event *event)
{
    int ret;

    ret = 0;
    switch (event->event) {
    case IB_CM_REQ_RECEIVED:
        ret = srpt_cm_req_recv(cm_id, &event->param.req_rcvd,
                       event->private_data);
        break;
    case IB_CM_REJ_RECEIVED:
        srpt_cm_rej_recv(cm_id);
        break;
    case IB_CM_RTU_RECEIVED:
    case IB_CM_USER_ESTABLISHED:
        srpt_cm_rtu_recv(cm_id);
        break;
    case IB_CM_DREQ_RECEIVED:
        srpt_cm_dreq_recv(cm_id);
        break;
    case IB_CM_DREP_RECEIVED:
        srpt_cm_drep_recv(cm_id);
        break;
    case IB_CM_TIMEWAIT_EXIT:
        srpt_cm_timewait_exit(cm_id);
        break;
    case IB_CM_REP_ERROR:
        srpt_cm_rep_error(cm_id);
        break;
    case IB_CM_DREQ_ERROR:
        printk(KERN_INFO "Received IB DREQ ERROR event.\n");
        break;
    case IB_CM_MRA_RECEIVED:
        printk(KERN_INFO "Received IB MRA event\n");
        break;
    default:
        printk(KERN_ERR "received unrecognized IB CM event %d\n",
               event->event);
        break;
    }

    return ret;
}

static int srpt_perform_rdmas(struct srpt_rdma_ch *ch,
                  struct srpt_send_ioctx *ioctx)
{
    struct ib_send_wr wr;
    struct ib_send_wr *bad_wr;
    struct rdma_iu *riu;
    int i;
    int ret;
    int sq_wr_avail;
    enum dma_data_direction dir;
    const int n_rdma = ioctx->n_rdma;

    dir = ioctx->cmd.data_direction;
    if (dir == DMA_TO_DEVICE) {
        /* write */
        ret = -ENOMEM;
        sq_wr_avail = atomic_sub_return(n_rdma, &ch->sq_wr_avail);
        if (sq_wr_avail < 0) {
            printk(KERN_WARNING "IB send queue full (needed %d)\n",
                   n_rdma);
            goto out;
        }
    }

    ioctx->rdma_aborted = false;
    ret = 0;
    riu = ioctx->rdma_ius;
    memset(&wr, 0, sizeof wr);

    for (i = 0; i < n_rdma; ++i, ++riu) {
        if (dir == DMA_FROM_DEVICE) {
            wr.opcode = IB_WR_RDMA_WRITE;
            wr.wr_id = encode_wr_id(i == n_rdma - 1 ?
                        SRPT_RDMA_WRITE_LAST :
                        SRPT_RDMA_MID,
                        ioctx->ioctx.index);
        } else {
            wr.opcode = IB_WR_RDMA_READ;
            wr.wr_id = encode_wr_id(i == n_rdma - 1 ?
                        SRPT_RDMA_READ_LAST :
                        SRPT_RDMA_MID,
                        ioctx->ioctx.index);
        }
        wr.next = NULL;
        wr.wr.rdma.remote_addr = riu->raddr;
        wr.wr.rdma.rkey = riu->rkey;
        wr.num_sge = riu->sge_cnt;
        wr.sg_list = riu->sge;

        /* only get completion event for the last rdma write */
        if (i == (n_rdma - 1) && dir == DMA_TO_DEVICE)
            wr.send_flags = IB_SEND_SIGNALED;

        ret = ib_post_send(ch->qp, &wr, &bad_wr);
        if (ret)
            break;
    }

    if (ret)
        printk(KERN_ERR "%s[%d]: ib_post_send() returned %d for %d/%d",
                 __func__, __LINE__, ret, i, n_rdma);
    if (ret && i > 0) {
        wr.num_sge = 0;
        wr.wr_id = encode_wr_id(SRPT_RDMA_ABORT, ioctx->ioctx.index);
        wr.send_flags = IB_SEND_SIGNALED;
        while (ch->state == CH_LIVE &&
            ib_post_send(ch->qp, &wr, &bad_wr) != 0) {
            printk(KERN_INFO "Trying to abort failed RDMA transfer [%d]",
                ioctx->ioctx.index);
            msleep(1000);
        }
        while (ch->state != CH_RELEASING && !ioctx->rdma_aborted) {
            printk(KERN_INFO "Waiting until RDMA abort finished [%d]",
                ioctx->ioctx.index);
            msleep(1000);
        }
    }
out:
    if (unlikely(dir == DMA_TO_DEVICE && ret < 0))
        atomic_add(n_rdma, &ch->sq_wr_avail);
    return ret;
}

static int srpt_xfer_data(struct srpt_rdma_ch *ch,
              struct srpt_send_ioctx *ioctx)
{
    int ret;

    ret = srpt_map_sg_to_ib_sge(ch, ioctx);
    if (ret) {
        printk(KERN_ERR "%s[%d] ret=%d\n", __func__, __LINE__, ret);
        goto out;
    }

    ret = srpt_perform_rdmas(ch, ioctx);
    if (ret) {
        if (ret == -EAGAIN || ret == -ENOMEM)
            printk(KERN_INFO "%s[%d] queue full -- ret=%d\n",
                   __func__, __LINE__, ret);
        else
            printk(KERN_ERR "%s[%d] fatal error -- ret=%d\n",
                   __func__, __LINE__, ret);
        goto out_unmap;
    }

out:
    return ret;
out_unmap:
    srpt_unmap_sg_to_ib_sge(ch, ioctx);
    goto out;
}

static int srpt_write_pending_status(struct se_cmd *se_cmd)
{
    struct srpt_send_ioctx *ioctx;

    ioctx = container_of(se_cmd, struct srpt_send_ioctx, cmd);
    return srpt_get_cmd_state(ioctx) == SRPT_STATE_NEED_DATA;
}

/*
 * srpt_write_pending() - Start data transfer from initiator to target (write).
 */
static int srpt_write_pending(struct se_cmd *se_cmd)
{
    struct srpt_rdma_ch *ch;
    struct srpt_send_ioctx *ioctx;
    enum srpt_command_state new_state;
    enum rdma_ch_state ch_state;
    int ret;

    ioctx = container_of(se_cmd, struct srpt_send_ioctx, cmd);

    new_state = srpt_set_cmd_state(ioctx, SRPT_STATE_NEED_DATA);
    WARN_ON(new_state == SRPT_STATE_DONE);

    ch = ioctx->ch;
    BUG_ON(!ch);

    ch_state = srpt_get_ch_state(ch);
    switch (ch_state) {
    case CH_CONNECTING:
        WARN(true, "unexpected channel state %d\n", ch_state);
        ret = -EINVAL;
        goto out;
    case CH_LIVE:
        break;
    case CH_DISCONNECTING:
    case CH_DRAINING:
    case CH_RELEASING:
        pr_debug("cmd with tag %lld: channel disconnecting\n",
             ioctx->tag);
        srpt_set_cmd_state(ioctx, SRPT_STATE_DATA_IN);
        ret = -EINVAL;
        goto out;
    }
    ret = srpt_xfer_data(ch, ioctx);

out:
    return ret;
}

static u8 tcm_to_srp_tsk_mgmt_status(const int tcm_mgmt_status)
{
    switch (tcm_mgmt_status) {
    case TMR_FUNCTION_COMPLETE:
        return SRP_TSK_MGMT_SUCCESS;
    case TMR_FUNCTION_REJECTED:
        return SRP_TSK_MGMT_FUNC_NOT_SUPP;
    }
    return SRP_TSK_MGMT_FAILED;
}

static int srpt_queue_response(struct se_cmd *cmd)
{
    struct srpt_rdma_ch *ch;
    struct srpt_send_ioctx *ioctx;
    enum srpt_command_state state;
    unsigned long flags;
    int ret;
    enum dma_data_direction dir;
    int resp_len;
    u8 srp_tm_status;

    ret = 0;

    ioctx = container_of(cmd, struct srpt_send_ioctx, cmd);
    ch = ioctx->ch;
    BUG_ON(!ch);

    spin_lock_irqsave(&ioctx->spinlock, flags);
    state = ioctx->state;
    switch (state) {
    case SRPT_STATE_NEW:
    case SRPT_STATE_DATA_IN:
        ioctx->state = SRPT_STATE_CMD_RSP_SENT;
        break;
    case SRPT_STATE_MGMT:
        ioctx->state = SRPT_STATE_MGMT_RSP_SENT;
        break;
    default:
        WARN(true, "ch %p; cmd %d: unexpected command state %d\n",
            ch, ioctx->ioctx.index, ioctx->state);
        break;
    }
    spin_unlock_irqrestore(&ioctx->spinlock, flags);

    if (unlikely(transport_check_aborted_status(&ioctx->cmd, false)
             || WARN_ON_ONCE(state == SRPT_STATE_CMD_RSP_SENT))) {
        atomic_inc(&ch->req_lim_delta);
        srpt_abort_cmd(ioctx);
        goto out;
    }

    dir = ioctx->cmd.data_direction;

    /* For read commands, transfer the data to the initiator. */
    if (dir == DMA_FROM_DEVICE && ioctx->cmd.data_length &&
        !ioctx->queue_status_only) {
        ret = srpt_xfer_data(ch, ioctx);
        if (ret) {
            printk(KERN_ERR "xfer_data failed for tag %llu\n",
                   ioctx->tag);
            goto out;
        }
    }

    if (state != SRPT_STATE_MGMT)
        resp_len = srpt_build_cmd_rsp(ch, ioctx, ioctx->tag,
                          cmd->scsi_status);
    else {
        srp_tm_status
            = tcm_to_srp_tsk_mgmt_status(cmd->se_tmr_req->response);
        resp_len = srpt_build_tskmgmt_rsp(ch, ioctx, srp_tm_status,
                         ioctx->tag);
    }
    ret = srpt_post_send(ch, ioctx, resp_len);
    if (ret) {
        printk(KERN_ERR "sending cmd response failed for tag %llu\n",
               ioctx->tag);
        srpt_unmap_sg_to_ib_sge(ch, ioctx);
        srpt_set_cmd_state(ioctx, SRPT_STATE_DONE);
        kref_put(&ioctx->kref, srpt_put_send_ioctx_kref);
    }

out:
    return ret;
}

static int srpt_queue_status(struct se_cmd *cmd)
{
    struct srpt_send_ioctx *ioctx;

    ioctx = container_of(cmd, struct srpt_send_ioctx, cmd);
    BUG_ON(ioctx->sense_data != cmd->sense_buffer);
    if (cmd->se_cmd_flags &
        (SCF_TRANSPORT_TASK_SENSE | SCF_EMULATED_TASK_SENSE))
        WARN_ON(cmd->scsi_status != SAM_STAT_CHECK_CONDITION);
    ioctx->queue_status_only = true;
    return srpt_queue_response(cmd);
}

static void srpt_refresh_port_work(struct work_struct *work)
{
    struct srpt_port *sport = container_of(work, struct srpt_port, work);

    srpt_refresh_port(sport);
}

static int srpt_ch_list_empty(struct srpt_device *sdev)
{
    int res;

    spin_lock_irq(&sdev->spinlock);
    res = list_empty(&sdev->rch_list);
    spin_unlock_irq(&sdev->spinlock);

    return res;
}

static int srpt_release_sdev(struct srpt_device *sdev)
{
    struct srpt_rdma_ch *ch, *tmp_ch;
    int res;

    WARN_ON_ONCE(irqs_disabled());

    BUG_ON(!sdev);

    spin_lock_irq(&sdev->spinlock);
    list_for_each_entry_safe(ch, tmp_ch, &sdev->rch_list, list)
        __srpt_close_ch(ch);
    spin_unlock_irq(&sdev->spinlock);

    res = wait_event_interruptible(sdev->ch_releaseQ,
                       srpt_ch_list_empty(sdev));
    if (res)
        printk(KERN_ERR "%s: interrupted.\n", __func__);

    return 0;
}

static struct srpt_port *__srpt_lookup_port(const char *name)
{
    struct ib_device *dev;
    struct srpt_device *sdev;
    struct srpt_port *sport;
    int i;

    list_for_each_entry(sdev, &srpt_dev_list, list) {
        dev = sdev->device;
        if (!dev)
            continue;

        for (i = 0; i < dev->phys_port_cnt; i++) {
            sport = &sdev->port[i];

            if (!strcmp(sport->port_guid, name))
                return sport;
        }
    }

    return NULL;
}

static struct srpt_port *srpt_lookup_port(const char *name)
{
    struct srpt_port *sport;

    spin_lock(&srpt_dev_lock);
    sport = __srpt_lookup_port(name);
    spin_unlock(&srpt_dev_lock);

    return sport;
}

static void srpt_add_one(struct ib_device *device)
{
    struct srpt_device *sdev;
    struct srpt_port *sport;
    struct ib_srq_init_attr srq_attr;
    int i;

    pr_debug("device = %p, device->dma_ops = %p\n", device,
         device->dma_ops);

    sdev = kzalloc(sizeof *sdev, GFP_KERNEL);
    if (!sdev)
        goto err;

    sdev->device = device;
    INIT_LIST_HEAD(&sdev->rch_list);
    init_waitqueue_head(&sdev->ch_releaseQ);
    spin_lock_init(&sdev->spinlock);

    if (ib_query_device(device, &sdev->dev_attr))
        goto free_dev;

    sdev->pd = ib_alloc_pd(device);
    if (IS_ERR(sdev->pd))
        goto free_dev;

    sdev->mr = ib_get_dma_mr(sdev->pd, IB_ACCESS_LOCAL_WRITE);
    if (IS_ERR(sdev->mr))
        goto err_pd;

    sdev->srq_size = min(srpt_srq_size, sdev->dev_attr.max_srq_wr);

    srq_attr.event_handler = srpt_srq_event;
    srq_attr.srq_context = (void *)sdev;
    srq_attr.attr.max_wr = sdev->srq_size;
    srq_attr.attr.max_sge = 1;
    srq_attr.attr.srq_limit = 0;
    srq_attr.srq_type = IB_SRQT_BASIC;

    sdev->srq = ib_create_srq(sdev->pd, &srq_attr);
    if (IS_ERR(sdev->srq))
        goto err_mr;

    pr_debug("%s: create SRQ #wr= %d max_allow=%d dev= %s\n",
         __func__, sdev->srq_size, sdev->dev_attr.max_srq_wr,
         device->name);

    if (!srpt_service_guid)
        srpt_service_guid = be64_to_cpu(device->node_guid);

    sdev->cm_id = ib_create_cm_id(device, srpt_cm_handler, sdev);
    if (IS_ERR(sdev->cm_id))
        goto err_srq;

    /* print out target login information */
    pr_debug("Target login info: id_ext=%016llx,ioc_guid=%016llx,"
         "pkey=ffff,service_id=%016llx\n", srpt_service_guid,
         srpt_service_guid, srpt_service_guid);

    /*
     * We do not have a consistent service_id (ie. also id_ext of target_id)
     * to identify this target. We currently use the guid of the first HCA
     * in the system as service_id; therefore, the target_id will change
     * if this HCA is gone bad and replaced by different HCA
     */
    if (ib_cm_listen(sdev->cm_id, cpu_to_be64(srpt_service_guid), 0, NULL))
        goto err_cm;

    INIT_IB_EVENT_HANDLER(&sdev->event_handler, sdev->device,
                  srpt_event_handler);
    if (ib_register_event_handler(&sdev->event_handler))
        goto err_cm;

    sdev->ioctx_ring = (struct srpt_recv_ioctx **)
        srpt_alloc_ioctx_ring(sdev, sdev->srq_size,
                      sizeof(*sdev->ioctx_ring[0]),
                      srp_max_req_size, DMA_FROM_DEVICE);
    if (!sdev->ioctx_ring)
        goto err_event;

    for (i = 0; i < sdev->srq_size; ++i)
        srpt_post_recv(sdev, sdev->ioctx_ring[i]);

    WARN_ON(sdev->device->phys_port_cnt > ARRAY_SIZE(sdev->port));

    for (i = 1; i <= sdev->device->phys_port_cnt; i++) {
        sport = &sdev->port[i - 1];
        sport->sdev = sdev;
        sport->port = i;
        sport->port_attrib.srp_max_rdma_size = DEFAULT_MAX_RDMA_SIZE;
        sport->port_attrib.srp_max_rsp_size = DEFAULT_MAX_RSP_SIZE;
        sport->port_attrib.srp_sq_size = DEF_SRPT_SQ_SIZE;
        INIT_WORK(&sport->work, srpt_refresh_port_work);
        INIT_LIST_HEAD(&sport->port_acl_list);
        spin_lock_init(&sport->port_acl_lock);

        if (srpt_refresh_port(sport)) {
            printk(KERN_ERR "MAD registration failed for %s-%d.\n",
                   srpt_sdev_name(sdev), i);
            goto err_ring;
        }
        snprintf(sport->port_guid, sizeof(sport->port_guid),
            "0x%016llx%016llx",
            be64_to_cpu(sport->gid.global.subnet_prefix),
            be64_to_cpu(sport->gid.global.interface_id));
    }

    spin_lock(&srpt_dev_lock);
    list_add_tail(&sdev->list, &srpt_dev_list);
    spin_unlock(&srpt_dev_lock);

out:
    ib_set_client_data(device, &srpt_client, sdev);
    pr_debug("added %s.\n", device->name);
    return;

err_ring:
    srpt_free_ioctx_ring((struct srpt_ioctx **)sdev->ioctx_ring, sdev,
                 sdev->srq_size, srp_max_req_size,
                 DMA_FROM_DEVICE);
err_event:
    ib_unregister_event_handler(&sdev->event_handler);
err_cm:
    ib_destroy_cm_id(sdev->cm_id);
err_srq:
    ib_destroy_srq(sdev->srq);
err_mr:
    ib_dereg_mr(sdev->mr);
err_pd:
    ib_dealloc_pd(sdev->pd);
free_dev:
    kfree(sdev);
err:
    sdev = NULL;
    printk(KERN_INFO "%s(%s) failed.\n", __func__, device->name);
    goto out;
}

static void srpt_remove_one(struct ib_device *device)
{
    struct srpt_device *sdev;
    int i;

    sdev = ib_get_client_data(device, &srpt_client);
    if (!sdev) {
        printk(KERN_INFO "%s(%s): nothing to do.\n", __func__,
               device->name);
        return;
    }

    srpt_unregister_mad_agent(sdev);

    ib_unregister_event_handler(&sdev->event_handler);

    /* Cancel any work queued by the just unregistered IB event handler. */
    for (i = 0; i < sdev->device->phys_port_cnt; i++)
        cancel_work_sync(&sdev->port[i].work);

    ib_destroy_cm_id(sdev->cm_id);

    /*
     * Unregistering a target must happen after destroying sdev->cm_id
     * such that no new SRP_LOGIN_REQ information units can arrive while
     * destroying the target.
     */
    spin_lock(&srpt_dev_lock);
    list_del(&sdev->list);
    spin_unlock(&srpt_dev_lock);
    srpt_release_sdev(sdev);

    ib_destroy_srq(sdev->srq);
    ib_dereg_mr(sdev->mr);
    ib_dealloc_pd(sdev->pd);

    srpt_free_ioctx_ring((struct srpt_ioctx **)sdev->ioctx_ring, sdev,
                 sdev->srq_size, srp_max_req_size, DMA_FROM_DEVICE);
    sdev->ioctx_ring = NULL;
    kfree(sdev);
}

static struct ib_client srpt_client = {
    .name = DRV_NAME,
    .add = srpt_add_one,
    .remove = srpt_remove_one
};

static int srpt_check_true(struct se_portal_group *se_tpg)
{
    return 1;
}

static int srpt_check_false(struct se_portal_group *se_tpg)
{
    return 0;
}

static char *srpt_get_fabric_name(void)
{
    return "srpt";
}

static u8 srpt_get_fabric_proto_ident(struct se_portal_group *se_tpg)
{
    return SCSI_TRANSPORTID_PROTOCOLID_SRP;
}

static char *srpt_get_fabric_wwn(struct se_portal_group *tpg)
{
    struct srpt_port *sport = container_of(tpg, struct srpt_port, port_tpg_1);

    return sport->port_guid;
}

static u16 srpt_get_tag(struct se_portal_group *tpg)
{
    return 1;
}

static u32 srpt_get_default_depth(struct se_portal_group *se_tpg)
{
    return 1;
}

static u32 srpt_get_pr_transport_id(struct se_portal_group *se_tpg,
                    struct se_node_acl *se_nacl,
                    struct t10_pr_registration *pr_reg,
                    int *format_code, unsigned char *buf)
{
    struct srpt_node_acl *nacl;
    struct spc_rdma_transport_id *tr_id;

    nacl = container_of(se_nacl, struct srpt_node_acl, nacl);
    tr_id = (void *)buf;
    tr_id->protocol_identifier = SCSI_TRANSPORTID_PROTOCOLID_SRP;
    memcpy(tr_id->i_port_id, nacl->i_port_id, sizeof(tr_id->i_port_id));
    return sizeof(*tr_id);
}

static u32 srpt_get_pr_transport_id_len(struct se_portal_group *se_tpg,
                    struct se_node_acl *se_nacl,
                    struct t10_pr_registration *pr_reg,
                    int *format_code)
{
    *format_code = 0;
    return sizeof(struct spc_rdma_transport_id);
}

static char *srpt_parse_pr_out_transport_id(struct se_portal_group *se_tpg,
                        const char *buf, u32 *out_tid_len,
                        char **port_nexus_ptr)
{
    struct spc_rdma_transport_id *tr_id;

    *port_nexus_ptr = NULL;
    *out_tid_len = sizeof(struct spc_rdma_transport_id);
    tr_id = (void *)buf;
    return (char *)tr_id->i_port_id;
}

static struct se_node_acl *srpt_alloc_fabric_acl(struct se_portal_group *se_tpg)
{
    struct srpt_node_acl *nacl;

    nacl = kzalloc(sizeof(struct srpt_node_acl), GFP_KERNEL);
    if (!nacl) {
        printk(KERN_ERR "Unable to allocate struct srpt_node_acl\n");
        return NULL;
    }

    return &nacl->nacl;
}

static void srpt_release_fabric_acl(struct se_portal_group *se_tpg,
                    struct se_node_acl *se_nacl)
{
    struct srpt_node_acl *nacl;

    nacl = container_of(se_nacl, struct srpt_node_acl, nacl);
    kfree(nacl);
}

static u32 srpt_tpg_get_inst_index(struct se_portal_group *se_tpg)
{
    return 1;
}

static void srpt_release_cmd(struct se_cmd *se_cmd)
{
}

static int srpt_shutdown_session(struct se_session *se_sess)
{
    return true;
}

static void srpt_close_session(struct se_session *se_sess)
{
    DECLARE_COMPLETION_ONSTACK(release_done);
    struct srpt_rdma_ch *ch;
    struct srpt_device *sdev;
    int res;

    ch = se_sess->fabric_sess_ptr;
    WARN_ON(ch->sess != se_sess);

    pr_debug("ch %p state %d\n", ch, srpt_get_ch_state(ch));

    sdev = ch->sport->sdev;
    spin_lock_irq(&sdev->spinlock);
    BUG_ON(ch->release_done);
    ch->release_done = &release_done;
    __srpt_close_ch(ch);
    spin_unlock_irq(&sdev->spinlock);

    res = wait_for_completion_timeout(&release_done, 60 * HZ);
    WARN_ON(res <= 0);
}

static u32 srpt_sess_get_index(struct se_session *se_sess)
{
    return 0;
}

static void srpt_set_default_node_attrs(struct se_node_acl *nacl)
{
}

static u32 srpt_get_task_tag(struct se_cmd *se_cmd)
{
    struct srpt_send_ioctx *ioctx;

    ioctx = container_of(se_cmd, struct srpt_send_ioctx, cmd);
    return ioctx->tag;
}

/* Note: only used from inside debug printk's by the TCM core. */
static int srpt_get_tcm_cmd_state(struct se_cmd *se_cmd)
{
    struct srpt_send_ioctx *ioctx;

    ioctx = container_of(se_cmd, struct srpt_send_ioctx, cmd);
    return srpt_get_cmd_state(ioctx);
}

static int srpt_parse_i_port_id(u8 i_port_id[16], const char *name)
{
    const char *p;
    unsigned len, count, leading_zero_bytes;
    int ret, rc;

    p = name;
    if (strnicmp(p, "0x", 2) == 0)
        p += 2;
    ret = -EINVAL;
    len = strlen(p);
    if (len % 2)
        goto out;
    count = min(len / 2, 16U);
    leading_zero_bytes = 16 - count;
    memset(i_port_id, 0, leading_zero_bytes);
    rc = hex2bin(i_port_id + leading_zero_bytes, p, count);
    if (rc < 0)
        pr_debug("hex2bin failed for srpt_parse_i_port_id: %d\n", rc);
    ret = 0;
out:
    return ret;
}

/*
 * configfs callback function invoked for
 * mkdir /sys/kernel/config/target/$driver/$port/$tpg/acls/$i_port_id
 */
static struct se_node_acl *srpt_make_nodeacl(struct se_portal_group *tpg,
                         struct config_group *group,
                         const char *name)
{
    struct srpt_port *sport = container_of(tpg, struct srpt_port, port_tpg_1);
    struct se_node_acl *se_nacl, *se_nacl_new;
    struct srpt_node_acl *nacl;
    int ret = 0;
    u32 nexus_depth = 1;
    u8 i_port_id[16];

    if (srpt_parse_i_port_id(i_port_id, name) < 0) {
        printk(KERN_ERR "invalid initiator port ID %s\n", name);
        ret = -EINVAL;
        goto err;
    }

    se_nacl_new = srpt_alloc_fabric_acl(tpg);
    if (!se_nacl_new) {
        ret = -ENOMEM;
        goto err;
    }
    /*
     * nacl_new may be released by core_tpg_add_initiator_node_acl()
     * when converting a node ACL from demo mode to explict
     */
    se_nacl = core_tpg_add_initiator_node_acl(tpg, se_nacl_new, name,
                          nexus_depth);
    if (IS_ERR(se_nacl)) {
        ret = PTR_ERR(se_nacl);
        goto err;
    }
    /* Locate our struct srpt_node_acl and set sdev and i_port_id. */
    nacl = container_of(se_nacl, struct srpt_node_acl, nacl);
    memcpy(&nacl->i_port_id[0], &i_port_id[0], 16);
    nacl->sport = sport;

    spin_lock_irq(&sport->port_acl_lock);
    list_add_tail(&nacl->list, &sport->port_acl_list);
    spin_unlock_irq(&sport->port_acl_lock);

    return se_nacl;
err:
    return ERR_PTR(ret);
}

/*
 * configfs callback function invoked for
 * rmdir /sys/kernel/config/target/$driver/$port/$tpg/acls/$i_port_id
 */
static void srpt_drop_nodeacl(struct se_node_acl *se_nacl)
{
    struct srpt_node_acl *nacl;
    struct srpt_device *sdev;
    struct srpt_port *sport;

    nacl = container_of(se_nacl, struct srpt_node_acl, nacl);
    sport = nacl->sport;
    sdev = sport->sdev;
    spin_lock_irq(&sport->port_acl_lock);
    list_del(&nacl->list);
    spin_unlock_irq(&sport->port_acl_lock);
    core_tpg_del_initiator_node_acl(&sport->port_tpg_1, se_nacl, 1);
    srpt_release_fabric_acl(NULL, se_nacl);
}

static ssize_t srpt_tpg_attrib_show_srp_max_rdma_size(
    struct se_portal_group *se_tpg,
    char *page)
{
    struct srpt_port *sport = container_of(se_tpg, struct srpt_port, port_tpg_1);

    return sprintf(page, "%u\n", sport->port_attrib.srp_max_rdma_size);
}

static ssize_t srpt_tpg_attrib_store_srp_max_rdma_size(
    struct se_portal_group *se_tpg,
    const char *page,
    size_t count)
{
    struct srpt_port *sport = container_of(se_tpg, struct srpt_port, port_tpg_1);
    unsigned long val;
    int ret;

    ret = strict_strtoul(page, 0, &val);
    if (ret < 0) {
        pr_err("strict_strtoul() failed with ret: %d\n", ret);
        return -EINVAL;
    }
    if (val > MAX_SRPT_RDMA_SIZE) {
        pr_err("val: %lu exceeds MAX_SRPT_RDMA_SIZE: %d\n", val,
            MAX_SRPT_RDMA_SIZE);
        return -EINVAL;
    }
    if (val < DEFAULT_MAX_RDMA_SIZE) {
        pr_err("val: %lu smaller than DEFAULT_MAX_RDMA_SIZE: %d\n",
            val, DEFAULT_MAX_RDMA_SIZE);
        return -EINVAL;
    }
    sport->port_attrib.srp_max_rdma_size = val;

    return count;
}

TF_TPG_ATTRIB_ATTR(srpt, srp_max_rdma_size, S_IRUGO | S_IWUSR);

static ssize_t srpt_tpg_attrib_show_srp_max_rsp_size(
    struct se_portal_group *se_tpg,
    char *page)
{
    struct srpt_port *sport = container_of(se_tpg, struct srpt_port, port_tpg_1);

    return sprintf(page, "%u\n", sport->port_attrib.srp_max_rsp_size);
}

static ssize_t srpt_tpg_attrib_store_srp_max_rsp_size(
    struct se_portal_group *se_tpg,
    const char *page,
    size_t count)
{
    struct srpt_port *sport = container_of(se_tpg, struct srpt_port, port_tpg_1);
    unsigned long val;
    int ret;

    ret = strict_strtoul(page, 0, &val);
    if (ret < 0) {
        pr_err("strict_strtoul() failed with ret: %d\n", ret);
        return -EINVAL;
    }
    if (val > MAX_SRPT_RSP_SIZE) {
        pr_err("val: %lu exceeds MAX_SRPT_RSP_SIZE: %d\n", val,
            MAX_SRPT_RSP_SIZE);
        return -EINVAL;
    }
    if (val < MIN_MAX_RSP_SIZE) {
        pr_err("val: %lu smaller than MIN_MAX_RSP_SIZE: %d\n", val,
            MIN_MAX_RSP_SIZE);
        return -EINVAL;
    }
    sport->port_attrib.srp_max_rsp_size = val;

    return count;
}

TF_TPG_ATTRIB_ATTR(srpt, srp_max_rsp_size, S_IRUGO | S_IWUSR);

static ssize_t srpt_tpg_attrib_show_srp_sq_size(
    struct se_portal_group *se_tpg,
    char *page)
{
    struct srpt_port *sport = container_of(se_tpg, struct srpt_port, port_tpg_1);

    return sprintf(page, "%u\n", sport->port_attrib.srp_sq_size);
}

static ssize_t srpt_tpg_attrib_store_srp_sq_size(
    struct se_portal_group *se_tpg,
    const char *page,
    size_t count)
{
    struct srpt_port *sport = container_of(se_tpg, struct srpt_port, port_tpg_1);
    unsigned long val;
    int ret;

    ret = strict_strtoul(page, 0, &val);
    if (ret < 0) {
        pr_err("strict_strtoul() failed with ret: %d\n", ret);
        return -EINVAL;
    }
    if (val > MAX_SRPT_SRQ_SIZE) {
        pr_err("val: %lu exceeds MAX_SRPT_SRQ_SIZE: %d\n", val,
            MAX_SRPT_SRQ_SIZE);
        return -EINVAL;
    }
    if (val < MIN_SRPT_SRQ_SIZE) {
        pr_err("val: %lu smaller than MIN_SRPT_SRQ_SIZE: %d\n", val,
            MIN_SRPT_SRQ_SIZE);
        return -EINVAL;
    }
    sport->port_attrib.srp_sq_size = val;

    return count;
}

TF_TPG_ATTRIB_ATTR(srpt, srp_sq_size, S_IRUGO | S_IWUSR);

static struct configfs_attribute *srpt_tpg_attrib_attrs[] = {
    &srpt_tpg_attrib_srp_max_rdma_size.attr,
    &srpt_tpg_attrib_srp_max_rsp_size.attr,
    &srpt_tpg_attrib_srp_sq_size.attr,
    NULL,
};

static ssize_t srpt_tpg_show_enable(
    struct se_portal_group *se_tpg,
    char *page)
{
    struct srpt_port *sport = container_of(se_tpg, struct srpt_port, port_tpg_1);

    return snprintf(page, PAGE_SIZE, "%d\n", (sport->enabled) ? 1: 0);
}

static ssize_t srpt_tpg_store_enable(
    struct se_portal_group *se_tpg,
    const char *page,
    size_t count)
{
    struct srpt_port *sport = container_of(se_tpg, struct srpt_port, port_tpg_1);
    unsigned long tmp;
        int ret;

    ret = strict_strtoul(page, 0, &tmp);
    if (ret < 0) {
        printk(KERN_ERR "Unable to extract srpt_tpg_store_enable\n");
        return -EINVAL;
    }

    if ((tmp != 0) && (tmp != 1)) {
        printk(KERN_ERR "Illegal value for srpt_tpg_store_enable: %lu\n", tmp);
        return -EINVAL;
    }
    if (tmp == 1)
        sport->enabled = true;
    else
        sport->enabled = false;

    return count;
}

TF_TPG_BASE_ATTR(srpt, enable, S_IRUGO | S_IWUSR);

static struct configfs_attribute *srpt_tpg_attrs[] = {
    &srpt_tpg_enable.attr,
    NULL,
};

static struct se_portal_group *srpt_make_tpg(struct se_wwn *wwn,
                         struct config_group *group,
                         const char *name)
{
    struct srpt_port *sport = container_of(wwn, struct srpt_port, port_wwn);
    int res;

    /* Initialize sport->port_wwn and sport->port_tpg_1 */
    res = core_tpg_register(&srpt_target->tf_ops, &sport->port_wwn,
            &sport->port_tpg_1, sport, TRANSPORT_TPG_TYPE_NORMAL);
    if (res)
        return ERR_PTR(res);

    return &sport->port_tpg_1;
}

static void srpt_drop_tpg(struct se_portal_group *tpg)
{
    struct srpt_port *sport = container_of(tpg,
                struct srpt_port, port_tpg_1);

    sport->enabled = false;
    core_tpg_deregister(&sport->port_tpg_1);
}

static struct se_wwn *srpt_make_tport(struct target_fabric_configfs *tf,
                      struct config_group *group,
                      const char *name)
{
    struct srpt_port *sport;
    int ret;

    sport = srpt_lookup_port(name);
    pr_debug("make_tport(%s)\n", name);
    ret = -EINVAL;
    if (!sport)
        goto err;

    return &sport->port_wwn;

err:
    return ERR_PTR(ret);
}

static void srpt_drop_tport(struct se_wwn *wwn)
{
    struct srpt_port *sport = container_of(wwn, struct srpt_port, port_wwn);

    pr_debug("drop_tport(%s\n", config_item_name(&sport->port_wwn.wwn_group.cg_item));
}

static ssize_t srpt_wwn_show_attr_version(struct target_fabric_configfs *tf,
                          char *buf)
{
    return scnprintf(buf, PAGE_SIZE, "%s\n", DRV_VERSION);
}

TF_WWN_ATTR_RO(srpt, version);

static struct configfs_attribute *srpt_wwn_attrs[] = {
    &srpt_wwn_version.attr,
    NULL,
};

static struct target_core_fabric_ops srpt_template = {
    .get_fabric_name        = srpt_get_fabric_name,
    .get_fabric_proto_ident     = srpt_get_fabric_proto_ident,
    .tpg_get_wwn            = srpt_get_fabric_wwn,
    .tpg_get_tag            = srpt_get_tag,
    .tpg_get_default_depth      = srpt_get_default_depth,
    .tpg_get_pr_transport_id    = srpt_get_pr_transport_id,
    .tpg_get_pr_transport_id_len    = srpt_get_pr_transport_id_len,
    .tpg_parse_pr_out_transport_id  = srpt_parse_pr_out_transport_id,
    .tpg_check_demo_mode        = srpt_check_false,
    .tpg_check_demo_mode_cache  = srpt_check_true,
    .tpg_check_demo_mode_write_protect = srpt_check_true,
    .tpg_check_prod_mode_write_protect = srpt_check_false,
    .tpg_alloc_fabric_acl       = srpt_alloc_fabric_acl,
    .tpg_release_fabric_acl     = srpt_release_fabric_acl,
    .tpg_get_inst_index     = srpt_tpg_get_inst_index,
    .release_cmd            = srpt_release_cmd,
    .check_stop_free        = srpt_check_stop_free,
    .shutdown_session       = srpt_shutdown_session,
    .close_session          = srpt_close_session,
    .sess_get_index         = srpt_sess_get_index,
    .sess_get_initiator_sid     = NULL,
    .write_pending          = srpt_write_pending,
    .write_pending_status       = srpt_write_pending_status,
    .set_default_node_attributes    = srpt_set_default_node_attrs,
    .get_task_tag           = srpt_get_task_tag,
    .get_cmd_state          = srpt_get_tcm_cmd_state,
    .queue_data_in          = srpt_queue_response,
    .queue_status           = srpt_queue_status,
    .queue_tm_rsp           = srpt_queue_response,
    /*
     * Setup function pointers for generic logic in
     * target_core_fabric_configfs.c
     */
    .fabric_make_wwn        = srpt_make_tport,
    .fabric_drop_wwn        = srpt_drop_tport,
    .fabric_make_tpg        = srpt_make_tpg,
    .fabric_drop_tpg        = srpt_drop_tpg,
    .fabric_post_link       = NULL,
    .fabric_pre_unlink      = NULL,
    .fabric_make_np         = NULL,
    .fabric_drop_np         = NULL,
    .fabric_make_nodeacl        = srpt_make_nodeacl,
    .fabric_drop_nodeacl        = srpt_drop_nodeacl,
};

static int __init srpt_init_module(void)
{
    int ret;

    ret = -EINVAL;
    if (srp_max_req_size < MIN_MAX_REQ_SIZE) {
        printk(KERN_ERR "invalid value %d for kernel module parameter"
               " srp_max_req_size -- must be at least %d.\n",
               srp_max_req_size, MIN_MAX_REQ_SIZE);
        goto out;
    }

    if (srpt_srq_size < MIN_SRPT_SRQ_SIZE
        || srpt_srq_size > MAX_SRPT_SRQ_SIZE) {
        printk(KERN_ERR "invalid value %d for kernel module parameter"
               " srpt_srq_size -- must be in the range [%d..%d].\n",
               srpt_srq_size, MIN_SRPT_SRQ_SIZE, MAX_SRPT_SRQ_SIZE);
        goto out;
    }

    srpt_target = target_fabric_configfs_init(THIS_MODULE, "srpt");
    if (IS_ERR(srpt_target)) {
        printk(KERN_ERR "couldn't register\n");
        ret = PTR_ERR(srpt_target);
        goto out;
    }

    srpt_target->tf_ops = srpt_template;

    /*
     * Set up default attribute lists.
     */
    srpt_target->tf_cit_tmpl.tfc_wwn_cit.ct_attrs = srpt_wwn_attrs;
    srpt_target->tf_cit_tmpl.tfc_tpg_base_cit.ct_attrs = srpt_tpg_attrs;
    srpt_target->tf_cit_tmpl.tfc_tpg_attrib_cit.ct_attrs = srpt_tpg_attrib_attrs;
    srpt_target->tf_cit_tmpl.tfc_tpg_param_cit.ct_attrs = NULL;
    srpt_target->tf_cit_tmpl.tfc_tpg_np_base_cit.ct_attrs = NULL;
    srpt_target->tf_cit_tmpl.tfc_tpg_nacl_base_cit.ct_attrs = NULL;
    srpt_target->tf_cit_tmpl.tfc_tpg_nacl_attrib_cit.ct_attrs = NULL;
    srpt_target->tf_cit_tmpl.tfc_tpg_nacl_auth_cit.ct_attrs = NULL;
    srpt_target->tf_cit_tmpl.tfc_tpg_nacl_param_cit.ct_attrs = NULL;

    ret = target_fabric_configfs_register(srpt_target);
    if (ret < 0) {
        printk(KERN_ERR "couldn't register\n");
        goto out_free_target;
    }

    ret = ib_register_client(&srpt_client);
    if (ret) {
        printk(KERN_ERR "couldn't register IB client\n");
        goto out_unregister_target;
    }

    return 0;

out_unregister_target:
    target_fabric_configfs_deregister(srpt_target);
    srpt_target = NULL;
out_free_target:
    if (srpt_target)
        target_fabric_configfs_free(srpt_target);
out:
    return ret;
}

static void __exit srpt_cleanup_module(void)
{
    ib_unregister_client(&srpt_client);
    target_fabric_configfs_deregister(srpt_target);
    srpt_target = NULL;
}

module_init(srpt_init_module);
module_exit(srpt_cleanup_module);