/*******************************************************************************
 * This file contains iSCSI extentions for RDMA (iSER) Verbs
 *
 * (c) Copyright 2013 RisingTide Systems LLC.
 *
 * Nicholas A. Bellinger <nab@linux-iscsi.org>
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation; either version 2 of the License, or
 * (at your option) any later version.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 ****************************************************************************/

#include <linux/string.h>
#include <linux/module.h>
#include <linux/scatterlist.h>
#include <linux/socket.h>
#include <linux/in.h>
#include <linux/in6.h>
#include <rdma/ib_verbs.h>
#include <rdma/rdma_cm.h>
#include <target/target_core_base.h>
#include <target/target_core_fabric.h>
#include <target/iscsi/iscsi_transport.h>

#include "isert_proto.h"
#include "ib_isert.h"

#define ISERT_MAX_CONN          8
#define ISER_MAX_RX_CQ_LEN      (ISERT_QP_MAX_RECV_DTOS * ISERT_MAX_CONN)
#define ISER_MAX_TX_CQ_LEN      (ISERT_QP_MAX_REQ_DTOS  * ISERT_MAX_CONN)

static DEFINE_MUTEX(device_list_mutex);
static LIST_HEAD(device_list);
static struct workqueue_struct *isert_rx_wq;
static struct workqueue_struct *isert_comp_wq;
static struct kmem_cache *isert_cmd_cache;

static void
isert_qp_event_callback(struct ib_event *e, void *context)
{
        struct isert_conn *isert_conn = (struct isert_conn *)context;

        pr_err("isert_qp_event_callback event: %d\n", e->event);
        switch (e->event) {
        case IB_EVENT_COMM_EST:
                rdma_notify(isert_conn->conn_cm_id, IB_EVENT_COMM_EST);
                break;
        case IB_EVENT_QP_LAST_WQE_REACHED:
                pr_warn("Reached TX IB_EVENT_QP_LAST_WQE_REACHED:\n");
                break;
        default:
                break;
        }
}

static int
isert_query_device(struct ib_device *ib_dev, struct ib_device_attr *devattr)
{
        int ret;

        ret = ib_query_device(ib_dev, devattr);
        if (ret) {
                pr_err("ib_query_device() failed: %d\n", ret);
                return ret;
        }
        pr_debug("devattr->max_sge: %d\n", devattr->max_sge);
        pr_debug("devattr->max_sge_rd: %d\n", devattr->max_sge_rd);

        return 0;
}

static int
isert_conn_setup_qp(struct isert_conn *isert_conn, struct rdma_cm_id *cma_id)
{
        struct isert_device *device = isert_conn->conn_device;
        struct ib_qp_init_attr attr;
        struct ib_device_attr devattr;
        int ret, index, min_index = 0;

        memset(&devattr, 0, sizeof(struct ib_device_attr));
        ret = isert_query_device(cma_id->device, &devattr);
        if (ret)
                return ret;

        mutex_lock(&device_list_mutex);
        for (index = 0; index < device->cqs_used; index++)
                if (device->cq_active_qps[index] <
                    device->cq_active_qps[min_index])
                        min_index = index;
        device->cq_active_qps[min_index]++;
        pr_debug("isert_conn_setup_qp: Using min_index: %d\n", min_index);
        mutex_unlock(&device_list_mutex);

        memset(&attr, 0, sizeof(struct ib_qp_init_attr));
        attr.event_handler = isert_qp_event_callback;
        attr.qp_context = isert_conn;
        attr.send_cq = device->dev_tx_cq[min_index];
        attr.recv_cq = device->dev_rx_cq[min_index];
        attr.cap.max_send_wr = ISERT_QP_MAX_REQ_DTOS;
        attr.cap.max_recv_wr = ISERT_QP_MAX_RECV_DTOS;
        /*
         * FIXME: Use devattr.max_sge - 2 for max_send_sge as
         * work-around for RDMA_READ..
         */
        attr.cap.max_send_sge = devattr.max_sge - 2;
        isert_conn->max_sge = attr.cap.max_send_sge;

        attr.cap.max_recv_sge = 1;
        attr.sq_sig_type = IB_SIGNAL_REQ_WR;
        attr.qp_type = IB_QPT_RC;

        pr_debug("isert_conn_setup_qp cma_id->device: %p\n",
                 cma_id->device);
        pr_debug("isert_conn_setup_qp conn_pd->device: %p\n",
                 isert_conn->conn_pd->device);

        ret = rdma_create_qp(cma_id, isert_conn->conn_pd, &attr);
        if (ret) {
                pr_err("rdma_create_qp failed for cma_id %d\n", ret);
                return ret;
        }
        isert_conn->conn_qp = cma_id->qp;
        pr_debug("rdma_create_qp() returned success >>>>>>>>>>>>>>>>>>>>>>>>>.\n");

        return 0;
}

static void
isert_cq_event_callback(struct ib_event *e, void *context)
{
        pr_debug("isert_cq_event_callback event: %d\n", e->event);
}

static int
isert_alloc_rx_descriptors(struct isert_conn *isert_conn)
{
        struct ib_device *ib_dev = isert_conn->conn_cm_id->device;
        struct iser_rx_desc *rx_desc;
        struct ib_sge *rx_sg;
        u64 dma_addr;
        int i, j;

        isert_conn->conn_rx_descs = kzalloc(ISERT_QP_MAX_RECV_DTOS *
                                sizeof(struct iser_rx_desc), GFP_KERNEL);
        if (!isert_conn->conn_rx_descs)
                goto fail;

        rx_desc = isert_conn->conn_rx_descs;

        for (i = 0; i < ISERT_QP_MAX_RECV_DTOS; i++, rx_desc++)  {
                dma_addr = ib_dma_map_single(ib_dev, (void *)rx_desc,
                                        ISER_RX_PAYLOAD_SIZE, DMA_FROM_DEVICE);
                if (ib_dma_mapping_error(ib_dev, dma_addr))
                        goto dma_map_fail;

                rx_desc->dma_addr = dma_addr;

                rx_sg = &rx_desc->rx_sg;
                rx_sg->addr = rx_desc->dma_addr;
                rx_sg->length = ISER_RX_PAYLOAD_SIZE;
                rx_sg->lkey = isert_conn->conn_mr->lkey;
        }

        isert_conn->conn_rx_desc_head = 0;
        return 0;

dma_map_fail:
        rx_desc = isert_conn->conn_rx_descs;
        for (j = 0; j < i; j++, rx_desc++) {
                ib_dma_unmap_single(ib_dev, rx_desc->dma_addr,
                                    ISER_RX_PAYLOAD_SIZE, DMA_FROM_DEVICE);
        }
        kfree(isert_conn->conn_rx_descs);
        isert_conn->conn_rx_descs = NULL;
fail:
        return -ENOMEM;
}

static void
isert_free_rx_descriptors(struct isert_conn *isert_conn)
{
        struct ib_device *ib_dev = isert_conn->conn_cm_id->device;
        struct iser_rx_desc *rx_desc;
        int i;

        if (!isert_conn->conn_rx_descs)
                return;

        rx_desc = isert_conn->conn_rx_descs;
        for (i = 0; i < ISERT_QP_MAX_RECV_DTOS; i++, rx_desc++)  {
                ib_dma_unmap_single(ib_dev, rx_desc->dma_addr,
                                    ISER_RX_PAYLOAD_SIZE, DMA_FROM_DEVICE);
        }

        kfree(isert_conn->conn_rx_descs);
        isert_conn->conn_rx_descs = NULL;
}

static void isert_cq_tx_callback(struct ib_cq *, void *);
static void isert_cq_rx_callback(struct ib_cq *, void *);

static int
isert_create_device_ib_res(struct isert_device *device)
{
        struct ib_device *ib_dev = device->ib_device;
        struct isert_cq_desc *cq_desc;
        int ret = 0, i, j;

        device->cqs_used = min_t(int, num_online_cpus(),
                                 device->ib_device->num_comp_vectors);
        device->cqs_used = min(ISERT_MAX_CQ, device->cqs_used);
        pr_debug("Using %d CQs, device %s supports %d vectors\n",
                 device->cqs_used, device->ib_device->name,
                 device->ib_device->num_comp_vectors);
        device->cq_desc = kzalloc(sizeof(struct isert_cq_desc) *
                                device->cqs_used, GFP_KERNEL);
        if (!device->cq_desc) {
                pr_err("Unable to allocate device->cq_desc\n");
                return -ENOMEM;
        }
        cq_desc = device->cq_desc;

        device->dev_pd = ib_alloc_pd(ib_dev);
        if (IS_ERR(device->dev_pd)) {
                ret = PTR_ERR(device->dev_pd);
                pr_err("ib_alloc_pd failed for dev_pd: %d\n", ret);
                goto out_cq_desc;
        }

        for (i = 0; i < device->cqs_used; i++) {
                cq_desc[i].device = device;
                cq_desc[i].cq_index = i;

                device->dev_rx_cq[i] = ib_create_cq(device->ib_device,
                                                isert_cq_rx_callback,
                                                isert_cq_event_callback,
                                                (void *)&cq_desc[i],
                                                ISER_MAX_RX_CQ_LEN, i);
                if (IS_ERR(device->dev_rx_cq[i]))
                        goto out_cq;

                device->dev_tx_cq[i] = ib_create_cq(device->ib_device,
                                                isert_cq_tx_callback,
                                                isert_cq_event_callback,
                                                (void *)&cq_desc[i],
                                                ISER_MAX_TX_CQ_LEN, i);
                if (IS_ERR(device->dev_tx_cq[i]))
                        goto out_cq;

                if (ib_req_notify_cq(device->dev_rx_cq[i], IB_CQ_NEXT_COMP))
                        goto out_cq;

                if (ib_req_notify_cq(device->dev_tx_cq[i], IB_CQ_NEXT_COMP))
                        goto out_cq;
        }

        device->dev_mr = ib_get_dma_mr(device->dev_pd, IB_ACCESS_LOCAL_WRITE);
        if (IS_ERR(device->dev_mr)) {
                ret = PTR_ERR(device->dev_mr);
                pr_err("ib_get_dma_mr failed for dev_mr: %d\n", ret);
                goto out_cq;
        }

        return 0;

out_cq:
        for (j = 0; j < i; j++) {
                cq_desc = &device->cq_desc[j];

                if (device->dev_rx_cq[j]) {
                        cancel_work_sync(&cq_desc->cq_rx_work);
                        ib_destroy_cq(device->dev_rx_cq[j]);
                }
                if (device->dev_tx_cq[j]) {
                        cancel_work_sync(&cq_desc->cq_tx_work);
                        ib_destroy_cq(device->dev_tx_cq[j]);
                }
        }
        ib_dealloc_pd(device->dev_pd);

out_cq_desc:
        kfree(device->cq_desc);

        return ret;
}

static void
isert_free_device_ib_res(struct isert_device *device)
{
        struct isert_cq_desc *cq_desc;
        int i;

        for (i = 0; i < device->cqs_used; i++) {
                cq_desc = &device->cq_desc[i];

                cancel_work_sync(&cq_desc->cq_rx_work);
                cancel_work_sync(&cq_desc->cq_tx_work);
                ib_destroy_cq(device->dev_rx_cq[i]);
                ib_destroy_cq(device->dev_tx_cq[i]);
                device->dev_rx_cq[i] = NULL;
                device->dev_tx_cq[i] = NULL;
        }

        ib_dereg_mr(device->dev_mr);
        ib_dealloc_pd(device->dev_pd);
        kfree(device->cq_desc);
}

static void
isert_device_try_release(struct isert_device *device)
{
        mutex_lock(&device_list_mutex);
        device->refcount--;
        if (!device->refcount) {
                isert_free_device_ib_res(device);
                list_del(&device->dev_node);
                kfree(device);
        }
        mutex_unlock(&device_list_mutex);
}

static struct isert_device *
isert_device_find_by_ib_dev(struct rdma_cm_id *cma_id)
{
        struct isert_device *device;
        int ret;

        mutex_lock(&device_list_mutex);
        list_for_each_entry(device, &device_list, dev_node) {
                if (device->ib_device->node_guid == cma_id->device->node_guid) {
                        device->refcount++;
                        mutex_unlock(&device_list_mutex);
                        return device;
                }
        }

        device = kzalloc(sizeof(struct isert_device), GFP_KERNEL);
        if (!device) {
                mutex_unlock(&device_list_mutex);
                return ERR_PTR(-ENOMEM);
        }

        INIT_LIST_HEAD(&device->dev_node);

        device->ib_device = cma_id->device;
        ret = isert_create_device_ib_res(device);
        if (ret) {
                kfree(device);
                mutex_unlock(&device_list_mutex);
                return ERR_PTR(ret);
        }

        device->refcount++;
        list_add_tail(&device->dev_node, &device_list);
        mutex_unlock(&device_list_mutex);

        return device;
}

static int
isert_connect_request(struct rdma_cm_id *cma_id, struct rdma_cm_event *event)
{
        struct iscsi_np *np = cma_id->context;
        struct isert_np *isert_np = np->np_context;
        struct isert_conn *isert_conn;
        struct isert_device *device;
        struct ib_device *ib_dev = cma_id->device;
        int ret = 0;

        pr_debug("Entering isert_connect_request cma_id: %p, context: %p\n",
                 cma_id, cma_id->context);

        isert_conn = kzalloc(sizeof(struct isert_conn), GFP_KERNEL);
        if (!isert_conn) {
                pr_err("Unable to allocate isert_conn\n");
                return -ENOMEM;
        }
        isert_conn->state = ISER_CONN_INIT;
        INIT_LIST_HEAD(&isert_conn->conn_accept_node);
        init_completion(&isert_conn->conn_login_comp);
        init_waitqueue_head(&isert_conn->conn_wait);
        init_waitqueue_head(&isert_conn->conn_wait_comp_err);
        kref_init(&isert_conn->conn_kref);
        kref_get(&isert_conn->conn_kref);

        cma_id->context = isert_conn;
        isert_conn->conn_cm_id = cma_id;
        isert_conn->responder_resources = event->param.conn.responder_resources;
        isert_conn->initiator_depth = event->param.conn.initiator_depth;
        pr_debug("Using responder_resources: %u initiator_depth: %u\n",
                 isert_conn->responder_resources, isert_conn->initiator_depth);

        isert_conn->login_buf = kzalloc(ISCSI_DEF_MAX_RECV_SEG_LEN +
                                        ISER_RX_LOGIN_SIZE, GFP_KERNEL);
        if (!isert_conn->login_buf) {
                pr_err("Unable to allocate isert_conn->login_buf\n");
                ret = -ENOMEM;
                goto out;
        }

        isert_conn->login_req_buf = isert_conn->login_buf;
        isert_conn->login_rsp_buf = isert_conn->login_buf +
                                    ISCSI_DEF_MAX_RECV_SEG_LEN;
        pr_debug("Set login_buf: %p login_req_buf: %p login_rsp_buf: %p\n",
                 isert_conn->login_buf, isert_conn->login_req_buf,
                 isert_conn->login_rsp_buf);

        isert_conn->login_req_dma = ib_dma_map_single(ib_dev,
                                (void *)isert_conn->login_req_buf,
                                ISCSI_DEF_MAX_RECV_SEG_LEN, DMA_FROM_DEVICE);

        ret = ib_dma_mapping_error(ib_dev, isert_conn->login_req_dma);
        if (ret) {
                pr_err("ib_dma_mapping_error failed for login_req_dma: %d\n",
                       ret);
                isert_conn->login_req_dma = 0;
                goto out_login_buf;
        }

        isert_conn->login_rsp_dma = ib_dma_map_single(ib_dev,
                                        (void *)isert_conn->login_rsp_buf,
                                        ISER_RX_LOGIN_SIZE, DMA_TO_DEVICE);

        ret = ib_dma_mapping_error(ib_dev, isert_conn->login_rsp_dma);
        if (ret) {
                pr_err("ib_dma_mapping_error failed for login_rsp_dma: %d\n",
                       ret);
                isert_conn->login_rsp_dma = 0;
                goto out_req_dma_map;
        }

        device = isert_device_find_by_ib_dev(cma_id);
        if (IS_ERR(device)) {
                ret = PTR_ERR(device);
                goto out_rsp_dma_map;
        }

        isert_conn->conn_device = device;
        isert_conn->conn_pd = device->dev_pd;
        isert_conn->conn_mr = device->dev_mr;

        ret = isert_conn_setup_qp(isert_conn, cma_id);
        if (ret)
                goto out_conn_dev;

        mutex_lock(&isert_np->np_accept_mutex);
        list_add_tail(&isert_np->np_accept_list, &isert_conn->conn_accept_node);
        mutex_unlock(&isert_np->np_accept_mutex);

        pr_debug("isert_connect_request() waking up np_accept_wq: %p\n", np);
        wake_up(&isert_np->np_accept_wq);
        return 0;

out_conn_dev:
        isert_device_try_release(device);
out_rsp_dma_map:
        ib_dma_unmap_single(ib_dev, isert_conn->login_rsp_dma,
                            ISER_RX_LOGIN_SIZE, DMA_TO_DEVICE);
out_req_dma_map:
        ib_dma_unmap_single(ib_dev, isert_conn->login_req_dma,
                            ISCSI_DEF_MAX_RECV_SEG_LEN, DMA_FROM_DEVICE);
out_login_buf:
        kfree(isert_conn->login_buf);
out:
        kfree(isert_conn);
        return ret;
}

static void
isert_connect_release(struct isert_conn *isert_conn)
{
        struct ib_device *ib_dev = isert_conn->conn_cm_id->device;
        struct isert_device *device = isert_conn->conn_device;
        int cq_index;

        pr_debug("Entering isert_connect_release(): >>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>\n");

        if (isert_conn->conn_qp) {
                cq_index = ((struct isert_cq_desc *)
                        isert_conn->conn_qp->recv_cq->cq_context)->cq_index;
                pr_debug("isert_connect_release: cq_index: %d\n", cq_index);
                isert_conn->conn_device->cq_active_qps[cq_index]--;

                rdma_destroy_qp(isert_conn->conn_cm_id);
        }

        isert_free_rx_descriptors(isert_conn);
        rdma_destroy_id(isert_conn->conn_cm_id);

        if (isert_conn->login_buf) {
                ib_dma_unmap_single(ib_dev, isert_conn->login_rsp_dma,
                                    ISER_RX_LOGIN_SIZE, DMA_TO_DEVICE);
                ib_dma_unmap_single(ib_dev, isert_conn->login_req_dma,
                                    ISCSI_DEF_MAX_RECV_SEG_LEN,
                                    DMA_FROM_DEVICE);
                kfree(isert_conn->login_buf);
        }
        kfree(isert_conn);

        if (device)
                isert_device_try_release(device);

        pr_debug("Leaving isert_connect_release >>>>>>>>>>>>\n");
}

static void
isert_connected_handler(struct rdma_cm_id *cma_id)
{
        return;
}

static void
isert_release_conn_kref(struct kref *kref)
{
        struct isert_conn *isert_conn = container_of(kref,
                                struct isert_conn, conn_kref);

        pr_debug("Calling isert_connect_release for final kref %s/%d\n",
                 current->comm, current->pid);

        isert_connect_release(isert_conn);
}

static void
isert_put_conn(struct isert_conn *isert_conn)
{
        kref_put(&isert_conn->conn_kref, isert_release_conn_kref);
}

static void
isert_disconnect_work(struct work_struct *work)
{
        struct isert_conn *isert_conn = container_of(work,
                                struct isert_conn, conn_logout_work);

        pr_debug("isert_disconnect_work(): >>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>\n");

        isert_conn->state = ISER_CONN_DOWN;

        if (isert_conn->post_recv_buf_count == 0 &&
            atomic_read(&isert_conn->post_send_buf_count) == 0) {
                pr_debug("Calling wake_up(&isert_conn->conn_wait);\n");
                wake_up(&isert_conn->conn_wait);
        }

        isert_put_conn(isert_conn);
}

static void
isert_disconnected_handler(struct rdma_cm_id *cma_id)
{
        struct isert_conn *isert_conn = (struct isert_conn *)cma_id->context;

        INIT_WORK(&isert_conn->conn_logout_work, isert_disconnect_work);
        schedule_work(&isert_conn->conn_logout_work);
}

static int
isert_cma_handler(struct rdma_cm_id *cma_id, struct rdma_cm_event *event)
{
        int ret = 0;

        pr_debug("isert_cma_handler: event %d status %d conn %p id %p\n",
                 event->event, event->status, cma_id->context, cma_id);

        switch (event->event) {
        case RDMA_CM_EVENT_CONNECT_REQUEST:
                pr_debug("RDMA_CM_EVENT_CONNECT_REQUEST: >>>>>>>>>>>>>>>\n");
                ret = isert_connect_request(cma_id, event);
                break;
        case RDMA_CM_EVENT_ESTABLISHED:
                pr_debug("RDMA_CM_EVENT_ESTABLISHED >>>>>>>>>>>>>>\n");
                isert_connected_handler(cma_id);
                break;
        case RDMA_CM_EVENT_DISCONNECTED:
                pr_debug("RDMA_CM_EVENT_DISCONNECTED: >>>>>>>>>>>>>>\n");
                isert_disconnected_handler(cma_id);
                break;
        case RDMA_CM_EVENT_DEVICE_REMOVAL:
        case RDMA_CM_EVENT_ADDR_CHANGE:
                break;
        case RDMA_CM_EVENT_CONNECT_ERROR:
        default:
                pr_err("Unknown RDMA CMA event: %d\n", event->event);
                break;
        }

        if (ret != 0) {
                pr_err("isert_cma_handler failed RDMA_CM_EVENT: 0x%08x %d\n",
                       event->event, ret);
                dump_stack();
        }

        return ret;
}

static int
isert_post_recv(struct isert_conn *isert_conn, u32 count)
{
        struct ib_recv_wr *rx_wr, *rx_wr_failed;
        int i, ret;
        unsigned int rx_head = isert_conn->conn_rx_desc_head;
        struct iser_rx_desc *rx_desc;

        for (rx_wr = isert_conn->conn_rx_wr, i = 0; i < count; i++, rx_wr++) {
                rx_desc         = &isert_conn->conn_rx_descs[rx_head];
                rx_wr->wr_id    = (unsigned long)rx_desc;
                rx_wr->sg_list  = &rx_desc->rx_sg;
                rx_wr->num_sge  = 1;
                rx_wr->next     = rx_wr + 1;
                rx_head = (rx_head + 1) & (ISERT_QP_MAX_RECV_DTOS - 1);
        }

        rx_wr--;
        rx_wr->next = NULL; /* mark end of work requests list */

        isert_conn->post_recv_buf_count += count;
        ret = ib_post_recv(isert_conn->conn_qp, isert_conn->conn_rx_wr,
                                &rx_wr_failed);
        if (ret) {
                pr_err("ib_post_recv() failed with ret: %d\n", ret);
                isert_conn->post_recv_buf_count -= count;
        } else {
                pr_debug("isert_post_recv(): Posted %d RX buffers\n", count);
                isert_conn->conn_rx_desc_head = rx_head;
        }
        return ret;
}

static int
isert_post_send(struct isert_conn *isert_conn, struct iser_tx_desc *tx_desc)
{
        struct ib_device *ib_dev = isert_conn->conn_cm_id->device;
        struct ib_send_wr send_wr, *send_wr_failed;
        int ret;

        ib_dma_sync_single_for_device(ib_dev, tx_desc->dma_addr,
                                      ISER_HEADERS_LEN, DMA_TO_DEVICE);

        send_wr.next    = NULL;
        send_wr.wr_id   = (unsigned long)tx_desc;
        send_wr.sg_list = tx_desc->tx_sg;
        send_wr.num_sge = tx_desc->num_sge;
        send_wr.opcode  = IB_WR_SEND;
        send_wr.send_flags = IB_SEND_SIGNALED;

        atomic_inc(&isert_conn->post_send_buf_count);

        ret = ib_post_send(isert_conn->conn_qp, &send_wr, &send_wr_failed);
        if (ret) {
                pr_err("ib_post_send() failed, ret: %d\n", ret);
                atomic_dec(&isert_conn->post_send_buf_count);
        }

        return ret;
}

static void
isert_create_send_desc(struct isert_conn *isert_conn,
                       struct isert_cmd *isert_cmd,
                       struct iser_tx_desc *tx_desc)
{
        struct ib_device *ib_dev = isert_conn->conn_cm_id->device;

        ib_dma_sync_single_for_cpu(ib_dev, tx_desc->dma_addr,
                                   ISER_HEADERS_LEN, DMA_TO_DEVICE);

        memset(&tx_desc->iser_header, 0, sizeof(struct iser_hdr));
        tx_desc->iser_header.flags = ISER_VER;

        tx_desc->num_sge = 1;
        tx_desc->isert_cmd = isert_cmd;

        if (tx_desc->tx_sg[0].lkey != isert_conn->conn_mr->lkey) {
                tx_desc->tx_sg[0].lkey = isert_conn->conn_mr->lkey;
                pr_debug("tx_desc %p lkey mismatch, fixing\n", tx_desc);
        }
}

static int
isert_init_tx_hdrs(struct isert_conn *isert_conn,
                   struct iser_tx_desc *tx_desc)
{
        struct ib_device *ib_dev = isert_conn->conn_cm_id->device;
        u64 dma_addr;

        dma_addr = ib_dma_map_single(ib_dev, (void *)tx_desc,
                        ISER_HEADERS_LEN, DMA_TO_DEVICE);
        if (ib_dma_mapping_error(ib_dev, dma_addr)) {
                pr_err("ib_dma_mapping_error() failed\n");
                return -ENOMEM;
        }

        tx_desc->dma_addr = dma_addr;
        tx_desc->tx_sg[0].addr  = tx_desc->dma_addr;
        tx_desc->tx_sg[0].length = ISER_HEADERS_LEN;
        tx_desc->tx_sg[0].lkey = isert_conn->conn_mr->lkey;

        pr_debug("isert_init_tx_hdrs: Setup tx_sg[0].addr: 0x%llx length: %u"
                 " lkey: 0x%08x\n", tx_desc->tx_sg[0].addr,
                 tx_desc->tx_sg[0].length, tx_desc->tx_sg[0].lkey);

        return 0;
}

static void
isert_init_send_wr(struct isert_cmd *isert_cmd, struct ib_send_wr *send_wr)
{
        isert_cmd->rdma_wr.iser_ib_op = ISER_IB_SEND;
        send_wr->wr_id = (unsigned long)&isert_cmd->tx_desc;
        send_wr->opcode = IB_WR_SEND;
        send_wr->send_flags = IB_SEND_SIGNALED;
        send_wr->sg_list = &isert_cmd->tx_desc.tx_sg[0];
        send_wr->num_sge = isert_cmd->tx_desc.num_sge;
}

static int
isert_rdma_post_recvl(struct isert_conn *isert_conn)
{
        struct ib_recv_wr rx_wr, *rx_wr_fail;
        struct ib_sge sge;
        int ret;

        memset(&sge, 0, sizeof(struct ib_sge));
        sge.addr = isert_conn->login_req_dma;
        sge.length = ISER_RX_LOGIN_SIZE;
        sge.lkey = isert_conn->conn_mr->lkey;

        pr_debug("Setup sge: addr: %llx length: %d 0x%08x\n",
                sge.addr, sge.length, sge.lkey);

        memset(&rx_wr, 0, sizeof(struct ib_recv_wr));
        rx_wr.wr_id = (unsigned long)isert_conn->login_req_buf;
        rx_wr.sg_list = &sge;
        rx_wr.num_sge = 1;

        isert_conn->post_recv_buf_count++;
        ret = ib_post_recv(isert_conn->conn_qp, &rx_wr, &rx_wr_fail);
        if (ret) {
                pr_err("ib_post_recv() failed: %d\n", ret);
                isert_conn->post_recv_buf_count--;
        }

        pr_debug("ib_post_recv(): returned success >>>>>>>>>>>>>>>>>>>>>>>>\n");
        return ret;
}

static int
isert_put_login_tx(struct iscsi_conn *conn, struct iscsi_login *login,
                   u32 length)
{
        struct isert_conn *isert_conn = conn->context;
        struct ib_device *ib_dev = isert_conn->conn_cm_id->device;
        struct iser_tx_desc *tx_desc = &isert_conn->conn_login_tx_desc;
        int ret;

        isert_create_send_desc(isert_conn, NULL, tx_desc);

        memcpy(&tx_desc->iscsi_header, &login->rsp[0],
               sizeof(struct iscsi_hdr));

        isert_init_tx_hdrs(isert_conn, tx_desc);

        if (length > 0) {
                struct ib_sge *tx_dsg = &tx_desc->tx_sg[1];

                ib_dma_sync_single_for_cpu(ib_dev, isert_conn->login_rsp_dma,
                                           length, DMA_TO_DEVICE);

                memcpy(isert_conn->login_rsp_buf, login->rsp_buf, length);

                ib_dma_sync_single_for_device(ib_dev, isert_conn->login_rsp_dma,
                                              length, DMA_TO_DEVICE);

                tx_dsg->addr    = isert_conn->login_rsp_dma;
                tx_dsg->length  = length;
                tx_dsg->lkey    = isert_conn->conn_mr->lkey;
                tx_desc->num_sge = 2;
        }
        if (!login->login_failed) {
                if (login->login_complete) {
                        ret = isert_alloc_rx_descriptors(isert_conn);
                        if (ret)
                                return ret;

                        ret = isert_post_recv(isert_conn, ISERT_MIN_POSTED_RX);
                        if (ret)
                                return ret;

                        isert_conn->state = ISER_CONN_UP;
                        goto post_send;
                }

                ret = isert_rdma_post_recvl(isert_conn);
                if (ret)
                        return ret;
        }
post_send:
        ret = isert_post_send(isert_conn, tx_desc);
        if (ret)
                return ret;

        return 0;
}

static void
isert_rx_login_req(struct iser_rx_desc *rx_desc, int rx_buflen,
                   struct isert_conn *isert_conn)
{
        struct iscsi_conn *conn = isert_conn->conn;
        struct iscsi_login *login = conn->conn_login;
        int size;

        if (!login) {
                pr_err("conn->conn_login is NULL\n");
                dump_stack();
                return;
        }

        if (login->first_request) {
                struct iscsi_login_req *login_req =
                        (struct iscsi_login_req *)&rx_desc->iscsi_header;
                /*
                 * Setup the initial iscsi_login values from the leading
                 * login request PDU.
                 */
                login->leading_connection = (!login_req->tsih) ? 1 : 0;
                login->current_stage =
                        (login_req->flags & ISCSI_FLAG_LOGIN_CURRENT_STAGE_MASK)
                         >> 2;
                login->version_min      = login_req->min_version;
                login->version_max      = login_req->max_version;
                memcpy(login->isid, login_req->isid, 6);
                login->cmd_sn           = be32_to_cpu(login_req->cmdsn);
                login->init_task_tag    = login_req->itt;
                login->initial_exp_statsn = be32_to_cpu(login_req->exp_statsn);
                login->cid              = be16_to_cpu(login_req->cid);
                login->tsih             = be16_to_cpu(login_req->tsih);
        }

        memcpy(&login->req[0], (void *)&rx_desc->iscsi_header, ISCSI_HDR_LEN);

        size = min(rx_buflen, MAX_KEY_VALUE_PAIRS);
        pr_debug("Using login payload size: %d, rx_buflen: %d MAX_KEY_VALUE_PAIRS: %d\n",
                 size, rx_buflen, MAX_KEY_VALUE_PAIRS);
        memcpy(login->req_buf, &rx_desc->data[0], size);

        complete(&isert_conn->conn_login_comp);
}

static void
isert_release_cmd(struct iscsi_cmd *cmd)
{
        struct isert_cmd *isert_cmd = container_of(cmd, struct isert_cmd,
                                                   iscsi_cmd);

        pr_debug("Entering isert_release_cmd %p >>>>>>>>>>>>>>>.\n", isert_cmd);

        kfree(cmd->buf_ptr);
        kfree(cmd->tmr_req);

        kmem_cache_free(isert_cmd_cache, isert_cmd);
}

static struct iscsi_cmd
*isert_alloc_cmd(struct iscsi_conn *conn, gfp_t gfp)
{
        struct isert_conn *isert_conn = (struct isert_conn *)conn->context;
        struct isert_cmd *isert_cmd;

        isert_cmd = kmem_cache_zalloc(isert_cmd_cache, gfp);
        if (!isert_cmd) {
                pr_err("Unable to allocate isert_cmd\n");
                return NULL;
        }
        isert_cmd->conn = isert_conn;
        isert_cmd->iscsi_cmd.release_cmd = &isert_release_cmd;

        return &isert_cmd->iscsi_cmd;
}

static int
isert_handle_scsi_cmd(struct isert_conn *isert_conn,
                      struct isert_cmd *isert_cmd, struct iser_rx_desc *rx_desc,
                      unsigned char *buf)
{
        struct iscsi_cmd *cmd = &isert_cmd->iscsi_cmd;
        struct iscsi_conn *conn = isert_conn->conn;
        struct iscsi_scsi_req *hdr = (struct iscsi_scsi_req *)buf;
        struct scatterlist *sg;
        int imm_data, imm_data_len, unsol_data, sg_nents, rc;
        bool dump_payload = false;

        rc = iscsit_setup_scsi_cmd(conn, cmd, buf);
        if (rc < 0)
                return rc;

        imm_data = cmd->immediate_data;
        imm_data_len = cmd->first_burst_len;
        unsol_data = cmd->unsolicited_data;

        rc = iscsit_process_scsi_cmd(conn, cmd, hdr);
        if (rc < 0) {
                return 0;
        } else if (rc > 0) {
                dump_payload = true;
                goto sequence_cmd;
        }

        if (!imm_data)
                return 0;

        sg = &cmd->se_cmd.t_data_sg[0];
        sg_nents = max(1UL, DIV_ROUND_UP(imm_data_len, PAGE_SIZE));

        pr_debug("Copying Immediate SG: %p sg_nents: %u from %p imm_data_len: %d\n",
                 sg, sg_nents, &rx_desc->data[0], imm_data_len);

        sg_copy_from_buffer(sg, sg_nents, &rx_desc->data[0], imm_data_len);

        cmd->write_data_done += imm_data_len;

        if (cmd->write_data_done == cmd->se_cmd.data_length) {
                spin_lock_bh(&cmd->istate_lock);
                cmd->cmd_flags |= ICF_GOT_LAST_DATAOUT;
                cmd->i_state = ISTATE_RECEIVED_LAST_DATAOUT;
                spin_unlock_bh(&cmd->istate_lock);
        }

sequence_cmd:
        rc = iscsit_sequence_cmd(conn, cmd, hdr->cmdsn);

        if (!rc && dump_payload == false && unsol_data)
                iscsit_set_unsoliticed_dataout(cmd);

        if (rc == CMDSN_ERROR_CANNOT_RECOVER)
                return iscsit_add_reject_from_cmd(
                           ISCSI_REASON_PROTOCOL_ERROR,
                           1, 0, (unsigned char *)hdr, cmd);

        return 0;
}

static int
isert_handle_iscsi_dataout(struct isert_conn *isert_conn,
                           struct iser_rx_desc *rx_desc, unsigned char *buf)
{
        struct scatterlist *sg_start;
        struct iscsi_conn *conn = isert_conn->conn;
        struct iscsi_cmd *cmd = NULL;
        struct iscsi_data *hdr = (struct iscsi_data *)buf;
        u32 unsol_data_len = ntoh24(hdr->dlength);
        int rc, sg_nents, sg_off, page_off;

        rc = iscsit_check_dataout_hdr(conn, buf, &cmd);
        if (rc < 0)
                return rc;
        else if (!cmd)
                return 0;
        /*
         * FIXME: Unexpected unsolicited_data out
         */
        if (!cmd->unsolicited_data) {
                pr_err("Received unexpected solicited data payload\n");
                dump_stack();
                return -1;
        }

        pr_debug("Unsolicited DataOut unsol_data_len: %u, write_data_done: %u, data_length: %u\n",
                 unsol_data_len, cmd->write_data_done, cmd->se_cmd.data_length);

        sg_off = cmd->write_data_done / PAGE_SIZE;
        sg_start = &cmd->se_cmd.t_data_sg[sg_off];
        sg_nents = max(1UL, DIV_ROUND_UP(unsol_data_len, PAGE_SIZE));
        page_off = cmd->write_data_done % PAGE_SIZE;
        /*
         * FIXME: Non page-aligned unsolicited_data out
         */
        if (page_off) {
                pr_err("Received unexpected non-page aligned data payload\n");
                dump_stack();
                return -1;
        }
        pr_debug("Copying DataOut: sg_start: %p, sg_off: %u sg_nents: %u from %p %u\n",
                 sg_start, sg_off, sg_nents, &rx_desc->data[0], unsol_data_len);

        sg_copy_from_buffer(sg_start, sg_nents, &rx_desc->data[0],
                            unsol_data_len);

        rc = iscsit_check_dataout_payload(cmd, hdr, false);
        if (rc < 0)
                return rc;

        return 0;

}

static int
isert_rx_opcode(struct isert_conn *isert_conn, struct iser_rx_desc *rx_desc,
                uint32_t read_stag, uint64_t read_va,
                uint32_t write_stag, uint64_t write_va)
{
        struct iscsi_hdr *hdr = &rx_desc->iscsi_header;
        struct iscsi_conn *conn = isert_conn->conn;
        struct iscsi_cmd *cmd;
        struct isert_cmd *isert_cmd;
        int ret = -EINVAL;
        u8 opcode = (hdr->opcode & ISCSI_OPCODE_MASK);

        switch (opcode) {
        case ISCSI_OP_SCSI_CMD:
                cmd = iscsit_allocate_cmd(conn, GFP_KERNEL);
                if (!cmd)
                        break;

                isert_cmd = container_of(cmd, struct isert_cmd, iscsi_cmd);
                isert_cmd->read_stag = read_stag;
                isert_cmd->read_va = read_va;
                isert_cmd->write_stag = write_stag;
                isert_cmd->write_va = write_va;

                ret = isert_handle_scsi_cmd(isert_conn, isert_cmd,
                                        rx_desc, (unsigned char *)hdr);
                break;
        case ISCSI_OP_NOOP_OUT:
                cmd = iscsit_allocate_cmd(conn, GFP_KERNEL);
                if (!cmd)
                        break;

                ret = iscsit_handle_nop_out(conn, cmd, (unsigned char *)hdr);
                break;
        case ISCSI_OP_SCSI_DATA_OUT:
                ret = isert_handle_iscsi_dataout(isert_conn, rx_desc,
                                                (unsigned char *)hdr);
                break;
        case ISCSI_OP_SCSI_TMFUNC:
                cmd = iscsit_allocate_cmd(conn, GFP_KERNEL);
                if (!cmd)
                        break;

                ret = iscsit_handle_task_mgt_cmd(conn, cmd,
                                                (unsigned char *)hdr);
                break;
        case ISCSI_OP_LOGOUT:
                cmd = iscsit_allocate_cmd(conn, GFP_KERNEL);
                if (!cmd)
                        break;

                ret = iscsit_handle_logout_cmd(conn, cmd, (unsigned char *)hdr);
                if (ret > 0)
                        wait_for_completion_timeout(&conn->conn_logout_comp,
                                                    SECONDS_FOR_LOGOUT_COMP *
                                                    HZ);
                break;
        default:
                pr_err("Got unknown iSCSI OpCode: 0x%02x\n", opcode);
                dump_stack();
                break;
        }

        return ret;
}

static void
isert_rx_do_work(struct iser_rx_desc *rx_desc, struct isert_conn *isert_conn)
{
        struct iser_hdr *iser_hdr = &rx_desc->iser_header;
        uint64_t read_va = 0, write_va = 0;
        uint32_t read_stag = 0, write_stag = 0;
        int rc;

        switch (iser_hdr->flags & 0xF0) {
        case ISCSI_CTRL:
                if (iser_hdr->flags & ISER_RSV) {
                        read_stag = be32_to_cpu(iser_hdr->read_stag);
                        read_va = be64_to_cpu(iser_hdr->read_va);
                        pr_debug("ISER_RSV: read_stag: 0x%08x read_va: 0x%16llx\n",
                                 read_stag, (unsigned long long)read_va);
                }
                if (iser_hdr->flags & ISER_WSV) {
                        write_stag = be32_to_cpu(iser_hdr->write_stag);
                        write_va = be64_to_cpu(iser_hdr->write_va);
                        pr_debug("ISER_WSV: write__stag: 0x%08x write_va: 0x%16llx\n",
                                 write_stag, (unsigned long long)write_va);
                }

                pr_debug("ISER ISCSI_CTRL PDU\n");
                break;
        case ISER_HELLO:
                pr_err("iSER Hello message\n");
                break;
        default:
                pr_warn("Unknown iSER hdr flags: 0x%02x\n", iser_hdr->flags);
                break;
        }

        rc = isert_rx_opcode(isert_conn, rx_desc,
                             read_stag, read_va, write_stag, write_va);
}

static void
isert_rx_completion(struct iser_rx_desc *desc, struct isert_conn *isert_conn,
                    unsigned long xfer_len)
{
        struct ib_device *ib_dev = isert_conn->conn_cm_id->device;
        struct iscsi_hdr *hdr;
        u64 rx_dma;
        int rx_buflen, outstanding;

        if ((char *)desc == isert_conn->login_req_buf) {
                rx_dma = isert_conn->login_req_dma;
                rx_buflen = ISER_RX_LOGIN_SIZE;
                pr_debug("ISER login_buf: Using rx_dma: 0x%llx, rx_buflen: %d\n",
                         rx_dma, rx_buflen);
        } else {
                rx_dma = desc->dma_addr;
                rx_buflen = ISER_RX_PAYLOAD_SIZE;
                pr_debug("ISER req_buf: Using rx_dma: 0x%llx, rx_buflen: %d\n",
                         rx_dma, rx_buflen);
        }

        ib_dma_sync_single_for_cpu(ib_dev, rx_dma, rx_buflen, DMA_FROM_DEVICE);

        hdr = &desc->iscsi_header;
        pr_debug("iSCSI opcode: 0x%02x, ITT: 0x%08x, flags: 0x%02x dlen: %d\n",
                 hdr->opcode, hdr->itt, hdr->flags,
                 (int)(xfer_len - ISER_HEADERS_LEN));

        if ((char *)desc == isert_conn->login_req_buf)
                isert_rx_login_req(desc, xfer_len - ISER_HEADERS_LEN,
                                   isert_conn);
        else
                isert_rx_do_work(desc, isert_conn);

        ib_dma_sync_single_for_device(ib_dev, rx_dma, rx_buflen,
                                      DMA_FROM_DEVICE);

        isert_conn->post_recv_buf_count--;
        pr_debug("iSERT: Decremented post_recv_buf_count: %d\n",
                 isert_conn->post_recv_buf_count);

        if ((char *)desc == isert_conn->login_req_buf)
                return;

        outstanding = isert_conn->post_recv_buf_count;
        if (outstanding + ISERT_MIN_POSTED_RX <= ISERT_QP_MAX_RECV_DTOS) {
                int err, count = min(ISERT_QP_MAX_RECV_DTOS - outstanding,
                                ISERT_MIN_POSTED_RX);
                err = isert_post_recv(isert_conn, count);
                if (err) {
                        pr_err("isert_post_recv() count: %d failed, %d\n",
                               count, err);
                }
        }
}

static void
isert_unmap_cmd(struct isert_cmd *isert_cmd, struct isert_conn *isert_conn)
{
        struct isert_rdma_wr *wr = &isert_cmd->rdma_wr;
        struct ib_device *ib_dev = isert_conn->conn_cm_id->device;

        pr_debug("isert_unmap_cmd >>>>>>>>>>>>>>>>>>>>>>>\n");

        if (wr->sge) {
                ib_dma_unmap_sg(ib_dev, wr->sge, wr->num_sge, DMA_TO_DEVICE);
                wr->sge = NULL;
        }

        kfree(wr->send_wr);
        wr->send_wr = NULL;

        kfree(isert_cmd->ib_sge);
        isert_cmd->ib_sge = NULL;
}

static void
isert_put_cmd(struct isert_cmd *isert_cmd)
{
        struct iscsi_cmd *cmd = &isert_cmd->iscsi_cmd;
        struct isert_conn *isert_conn = isert_cmd->conn;
        struct iscsi_conn *conn;

        pr_debug("Entering isert_put_cmd: %p\n", isert_cmd);

        switch (cmd->iscsi_opcode) {
        case ISCSI_OP_SCSI_CMD:
                conn = isert_conn->conn;

                spin_lock_bh(&conn->cmd_lock);
                if (!list_empty(&cmd->i_conn_node))
                        list_del(&cmd->i_conn_node);
                spin_unlock_bh(&conn->cmd_lock);

                if (cmd->data_direction == DMA_TO_DEVICE)
                        iscsit_stop_dataout_timer(cmd);

                isert_unmap_cmd(isert_cmd, isert_conn);
                /*
                 * Fall-through
                 */
        case ISCSI_OP_SCSI_TMFUNC:
                transport_generic_free_cmd(&cmd->se_cmd, 0);
                break;
        case ISCSI_OP_REJECT:
        case ISCSI_OP_NOOP_OUT:
                conn = isert_conn->conn;

                spin_lock_bh(&conn->cmd_lock);
                if (!list_empty(&cmd->i_conn_node))
                        list_del(&cmd->i_conn_node);
                spin_unlock_bh(&conn->cmd_lock);

                /*
                 * Handle special case for REJECT when iscsi_add_reject*() has
                 * overwritten the original iscsi_opcode assignment, and the
                 * associated cmd->se_cmd needs to be released.
                 */
                if (cmd->se_cmd.se_tfo != NULL) {
                        transport_generic_free_cmd(&cmd->se_cmd, 0);
                        break;
                }
                /*
                 * Fall-through
                 */
        default:
                isert_release_cmd(cmd);
                break;
        }
}

static void
isert_unmap_tx_desc(struct iser_tx_desc *tx_desc, struct ib_device *ib_dev)
{
        if (tx_desc->dma_addr != 0) {
                pr_debug("Calling ib_dma_unmap_single for tx_desc->dma_addr\n");
                ib_dma_unmap_single(ib_dev, tx_desc->dma_addr,
                                    ISER_HEADERS_LEN, DMA_TO_DEVICE);
                tx_desc->dma_addr = 0;
        }
}

static void
isert_completion_put(struct iser_tx_desc *tx_desc, struct isert_cmd *isert_cmd,
                     struct ib_device *ib_dev)
{
        if (isert_cmd->sense_buf_dma != 0) {
                pr_debug("Calling ib_dma_unmap_single for isert_cmd->sense_buf_dma\n");
                ib_dma_unmap_single(ib_dev, isert_cmd->sense_buf_dma,
                                    isert_cmd->sense_buf_len, DMA_TO_DEVICE);
                isert_cmd->sense_buf_dma = 0;
        }

        isert_unmap_tx_desc(tx_desc, ib_dev);
        isert_put_cmd(isert_cmd);
}

static void
isert_completion_rdma_read(struct iser_tx_desc *tx_desc,
                           struct isert_cmd *isert_cmd)
{
        struct isert_rdma_wr *wr = &isert_cmd->rdma_wr;
        struct iscsi_cmd *cmd = &isert_cmd->iscsi_cmd;
        struct se_cmd *se_cmd = &cmd->se_cmd;
        struct ib_device *ib_dev = isert_cmd->conn->conn_cm_id->device;

        iscsit_stop_dataout_timer(cmd);

        if (wr->sge) {
                pr_debug("isert_do_rdma_read_comp: Unmapping wr->sge from t_data_sg\n");
                ib_dma_unmap_sg(ib_dev, wr->sge, wr->num_sge, DMA_TO_DEVICE);
                wr->sge = NULL;
        }

        if (isert_cmd->ib_sge) {
                pr_debug("isert_do_rdma_read_comp: Freeing isert_cmd->ib_sge\n");
                kfree(isert_cmd->ib_sge);
                isert_cmd->ib_sge = NULL;
        }

        cmd->write_data_done = se_cmd->data_length;

        pr_debug("isert_do_rdma_read_comp, calling target_execute_cmd\n");
        spin_lock_bh(&cmd->istate_lock);
        cmd->cmd_flags |= ICF_GOT_LAST_DATAOUT;
        cmd->i_state = ISTATE_RECEIVED_LAST_DATAOUT;
        spin_unlock_bh(&cmd->istate_lock);

        target_execute_cmd(se_cmd);
}

static void
isert_do_control_comp(struct work_struct *work)
{
        struct isert_cmd *isert_cmd = container_of(work,
                        struct isert_cmd, comp_work);
        struct isert_conn *isert_conn = isert_cmd->conn;
        struct ib_device *ib_dev = isert_conn->conn_cm_id->device;
        struct iscsi_cmd *cmd = &isert_cmd->iscsi_cmd;

        switch (cmd->i_state) {
        case ISTATE_SEND_TASKMGTRSP:
                pr_debug("Calling iscsit_tmr_post_handler >>>>>>>>>>>>>>>>>\n");

                atomic_dec(&isert_conn->post_send_buf_count);
                iscsit_tmr_post_handler(cmd, cmd->conn);

                cmd->i_state = ISTATE_SENT_STATUS;
                isert_completion_put(&isert_cmd->tx_desc, isert_cmd, ib_dev);
                break;
        case ISTATE_SEND_REJECT:
                pr_debug("Got isert_do_control_comp ISTATE_SEND_REJECT: >>>\n");
                atomic_dec(&isert_conn->post_send_buf_count);

                cmd->i_state = ISTATE_SENT_STATUS;
                complete(&cmd->reject_comp);
                isert_completion_put(&isert_cmd->tx_desc, isert_cmd, ib_dev);
        case ISTATE_SEND_LOGOUTRSP:
                pr_debug("Calling iscsit_logout_post_handler >>>>>>>>>>>>>>\n");
                /*
                 * Call atomic_dec(&isert_conn->post_send_buf_count)
                 * from isert_free_conn()
                 */
                isert_conn->logout_posted = true;
                iscsit_logout_post_handler(cmd, cmd->conn);
                break;
        default:
                pr_err("Unknown do_control_comp i_state %d\n", cmd->i_state);
                dump_stack();
                break;
        }
}

static void
isert_response_completion(struct iser_tx_desc *tx_desc,
                          struct isert_cmd *isert_cmd,
                          struct isert_conn *isert_conn,
                          struct ib_device *ib_dev)
{
        struct iscsi_cmd *cmd = &isert_cmd->iscsi_cmd;

        if (cmd->i_state == ISTATE_SEND_TASKMGTRSP ||
            cmd->i_state == ISTATE_SEND_LOGOUTRSP) {
                isert_unmap_tx_desc(tx_desc, ib_dev);

                INIT_WORK(&isert_cmd->comp_work, isert_do_control_comp);
                queue_work(isert_comp_wq, &isert_cmd->comp_work);
                return;
        }
        atomic_dec(&isert_conn->post_send_buf_count);

        cmd->i_state = ISTATE_SENT_STATUS;
        isert_completion_put(tx_desc, isert_cmd, ib_dev);
}

static void
isert_send_completion(struct iser_tx_desc *tx_desc,
                      struct isert_conn *isert_conn)
{
        struct ib_device *ib_dev = isert_conn->conn_cm_id->device;
        struct isert_cmd *isert_cmd = tx_desc->isert_cmd;
        struct isert_rdma_wr *wr;

        if (!isert_cmd) {
                atomic_dec(&isert_conn->post_send_buf_count);
                isert_unmap_tx_desc(tx_desc, ib_dev);
                return;
        }
        wr = &isert_cmd->rdma_wr;

        switch (wr->iser_ib_op) {
        case ISER_IB_RECV:
                pr_err("isert_send_completion: Got ISER_IB_RECV\n");
                dump_stack();
                break;
        case ISER_IB_SEND:
                pr_debug("isert_send_completion: Got ISER_IB_SEND\n");
                isert_response_completion(tx_desc, isert_cmd,
                                          isert_conn, ib_dev);
                break;
        case ISER_IB_RDMA_WRITE:
                pr_err("isert_send_completion: Got ISER_IB_RDMA_WRITE\n");
                dump_stack();
                break;
        case ISER_IB_RDMA_READ:
                pr_debug("isert_send_completion: Got ISER_IB_RDMA_READ:\n");

                atomic_dec(&isert_conn->post_send_buf_count);
                isert_completion_rdma_read(tx_desc, isert_cmd);
                break;
        default:
                pr_err("Unknown wr->iser_ib_op: 0x%02x\n", wr->iser_ib_op);
                dump_stack();
                break;
        }
}

static void
isert_cq_comp_err(struct iser_tx_desc *tx_desc, struct isert_conn *isert_conn)
{
        struct ib_device *ib_dev = isert_conn->conn_cm_id->device;

        if (tx_desc) {
                struct isert_cmd *isert_cmd = tx_desc->isert_cmd;

                if (!isert_cmd)
                        isert_unmap_tx_desc(tx_desc, ib_dev);
                else
                        isert_completion_put(tx_desc, isert_cmd, ib_dev);
        }

        if (isert_conn->post_recv_buf_count == 0 &&
            atomic_read(&isert_conn->post_send_buf_count) == 0) {
                pr_debug("isert_cq_comp_err >>>>>>>>>>>>>>>>>>>>>>>>>>>>>>\n");
                pr_debug("Calling wake_up from isert_cq_comp_err\n");

                isert_conn->state = ISER_CONN_TERMINATING;
                wake_up(&isert_conn->conn_wait_comp_err);
        }
}

static void
isert_cq_tx_work(struct work_struct *work)
{
        struct isert_cq_desc *cq_desc = container_of(work,
                                struct isert_cq_desc, cq_tx_work);
        struct isert_device *device = cq_desc->device;
        int cq_index = cq_desc->cq_index;
        struct ib_cq *tx_cq = device->dev_tx_cq[cq_index];
        struct isert_conn *isert_conn;
        struct iser_tx_desc *tx_desc;
        struct ib_wc wc;

        while (ib_poll_cq(tx_cq, 1, &wc) == 1) {
                tx_desc = (struct iser_tx_desc *)(unsigned long)wc.wr_id;
                isert_conn = wc.qp->qp_context;

                if (wc.status == IB_WC_SUCCESS) {
                        isert_send_completion(tx_desc, isert_conn);
                } else {
                        pr_debug("TX wc.status != IB_WC_SUCCESS >>>>>>>>>>>>>>\n");
                        pr_debug("TX wc.status: 0x%08x\n", wc.status);
                        atomic_dec(&isert_conn->post_send_buf_count);
                        isert_cq_comp_err(tx_desc, isert_conn);
                }
        }

        ib_req_notify_cq(tx_cq, IB_CQ_NEXT_COMP);
}

static void
isert_cq_tx_callback(struct ib_cq *cq, void *context)
{
        struct isert_cq_desc *cq_desc = (struct isert_cq_desc *)context;

        INIT_WORK(&cq_desc->cq_tx_work, isert_cq_tx_work);
        queue_work(isert_comp_wq, &cq_desc->cq_tx_work);
}

static void
isert_cq_rx_work(struct work_struct *work)
{
        struct isert_cq_desc *cq_desc = container_of(work,
                        struct isert_cq_desc, cq_rx_work);
        struct isert_device *device = cq_desc->device;
        int cq_index = cq_desc->cq_index;
        struct ib_cq *rx_cq = device->dev_rx_cq[cq_index];
        struct isert_conn *isert_conn;
        struct iser_rx_desc *rx_desc;
        struct ib_wc wc;
        unsigned long xfer_len;

        while (ib_poll_cq(rx_cq, 1, &wc) == 1) {
                rx_desc = (struct iser_rx_desc *)(unsigned long)wc.wr_id;
                isert_conn = wc.qp->qp_context;

                if (wc.status == IB_WC_SUCCESS) {
                        xfer_len = (unsigned long)wc.byte_len;
                        isert_rx_completion(rx_desc, isert_conn, xfer_len);
                } else {
                        pr_debug("RX wc.status != IB_WC_SUCCESS >>>>>>>>>>>>>>\n");
                        if (wc.status != IB_WC_WR_FLUSH_ERR)
                                pr_debug("RX wc.status: 0x%08x\n", wc.status);

                        isert_conn->post_recv_buf_count--;
                        isert_cq_comp_err(NULL, isert_conn);
                }
        }

        ib_req_notify_cq(rx_cq, IB_CQ_NEXT_COMP);
}

static void
isert_cq_rx_callback(struct ib_cq *cq, void *context)
{
        struct isert_cq_desc *cq_desc = (struct isert_cq_desc *)context;

        INIT_WORK(&cq_desc->cq_rx_work, isert_cq_rx_work);
        queue_work(isert_rx_wq, &cq_desc->cq_rx_work);
}

static int
isert_post_response(struct isert_conn *isert_conn, struct isert_cmd *isert_cmd)
{
        struct ib_send_wr *wr_failed;
        int ret;

        atomic_inc(&isert_conn->post_send_buf_count);

        ret = ib_post_send(isert_conn->conn_qp, &isert_cmd->tx_desc.send_wr,
                           &wr_failed);
        if (ret) {
                pr_err("ib_post_send failed with %d\n", ret);
                atomic_dec(&isert_conn->post_send_buf_count);
                return ret;
        }
        return ret;
}

static int
isert_put_response(struct iscsi_conn *conn, struct iscsi_cmd *cmd)
{
        struct isert_cmd *isert_cmd = container_of(cmd,
                                        struct isert_cmd, iscsi_cmd);
        struct isert_conn *isert_conn = (struct isert_conn *)conn->context;
        struct ib_send_wr *send_wr = &isert_cmd->tx_desc.send_wr;
        struct iscsi_scsi_rsp *hdr = (struct iscsi_scsi_rsp *)
                                &isert_cmd->tx_desc.iscsi_header;

        isert_create_send_desc(isert_conn, isert_cmd, &isert_cmd->tx_desc);
        iscsit_build_rsp_pdu(cmd, conn, true, hdr);
        isert_init_tx_hdrs(isert_conn, &isert_cmd->tx_desc);
        /*
         * Attach SENSE DATA payload to iSCSI Response PDU
         */
        if (cmd->se_cmd.sense_buffer &&
            ((cmd->se_cmd.se_cmd_flags & SCF_TRANSPORT_TASK_SENSE) ||
            (cmd->se_cmd.se_cmd_flags & SCF_EMULATED_TASK_SENSE))) {
                struct ib_device *ib_dev = isert_conn->conn_cm_id->device;
                struct ib_sge *tx_dsg = &isert_cmd->tx_desc.tx_sg[1];
                u32 padding, sense_len;

                put_unaligned_be16(cmd->se_cmd.scsi_sense_length,
                                   cmd->sense_buffer);
                cmd->se_cmd.scsi_sense_length += sizeof(__be16);

                padding = -(cmd->se_cmd.scsi_sense_length) & 3;
                hton24(hdr->dlength, (u32)cmd->se_cmd.scsi_sense_length);
                sense_len = cmd->se_cmd.scsi_sense_length + padding;

                isert_cmd->sense_buf_dma = ib_dma_map_single(ib_dev,
                                (void *)cmd->sense_buffer, sense_len,
                                DMA_TO_DEVICE);

                isert_cmd->sense_buf_len = sense_len;
                tx_dsg->addr    = isert_cmd->sense_buf_dma;
                tx_dsg->length  = sense_len;
                tx_dsg->lkey    = isert_conn->conn_mr->lkey;
                isert_cmd->tx_desc.num_sge = 2;
        }

        isert_init_send_wr(isert_cmd, send_wr);

        pr_debug("Posting SCSI Response IB_WR_SEND >>>>>>>>>>>>>>>>>>>>>>\n");

        return isert_post_response(isert_conn, isert_cmd);
}

static int
isert_put_nopin(struct iscsi_cmd *cmd, struct iscsi_conn *conn,
                bool nopout_response)
{
        struct isert_cmd *isert_cmd = container_of(cmd,
                                struct isert_cmd, iscsi_cmd);
        struct isert_conn *isert_conn = (struct isert_conn *)conn->context;
        struct ib_send_wr *send_wr = &isert_cmd->tx_desc.send_wr;

        isert_create_send_desc(isert_conn, isert_cmd, &isert_cmd->tx_desc);
        iscsit_build_nopin_rsp(cmd, conn, (struct iscsi_nopin *)
                               &isert_cmd->tx_desc.iscsi_header,
                               nopout_response);
        isert_init_tx_hdrs(isert_conn, &isert_cmd->tx_desc);
        isert_init_send_wr(isert_cmd, send_wr);

        pr_debug("Posting NOPIN Reponse IB_WR_SEND >>>>>>>>>>>>>>>>>>>>>>\n");

        return isert_post_response(isert_conn, isert_cmd);
}

static int
isert_put_logout_rsp(struct iscsi_cmd *cmd, struct iscsi_conn *conn)
{
        struct isert_cmd *isert_cmd = container_of(cmd,
                                struct isert_cmd, iscsi_cmd);
        struct isert_conn *isert_conn = (struct isert_conn *)conn->context;
        struct ib_send_wr *send_wr = &isert_cmd->tx_desc.send_wr;

        isert_create_send_desc(isert_conn, isert_cmd, &isert_cmd->tx_desc);
        iscsit_build_logout_rsp(cmd, conn, (struct iscsi_logout_rsp *)
                                &isert_cmd->tx_desc.iscsi_header);
        isert_init_tx_hdrs(isert_conn, &isert_cmd->tx_desc);
        isert_init_send_wr(isert_cmd, send_wr);

        pr_debug("Posting Logout Response IB_WR_SEND >>>>>>>>>>>>>>>>>>>>>>\n");

        return isert_post_response(isert_conn, isert_cmd);
}

static int
isert_put_tm_rsp(struct iscsi_cmd *cmd, struct iscsi_conn *conn)
{
        struct isert_cmd *isert_cmd = container_of(cmd,
                                struct isert_cmd, iscsi_cmd);
        struct isert_conn *isert_conn = (struct isert_conn *)conn->context;
        struct ib_send_wr *send_wr = &isert_cmd->tx_desc.send_wr;

        isert_create_send_desc(isert_conn, isert_cmd, &isert_cmd->tx_desc);
        iscsit_build_task_mgt_rsp(cmd, conn, (struct iscsi_tm_rsp *)
                                  &isert_cmd->tx_desc.iscsi_header);
        isert_init_tx_hdrs(isert_conn, &isert_cmd->tx_desc);
        isert_init_send_wr(isert_cmd, send_wr);

        pr_debug("Posting Task Management Response IB_WR_SEND >>>>>>>>>>>>>>>>>>>>>>\n");

        return isert_post_response(isert_conn, isert_cmd);
}

static int
isert_put_reject(struct iscsi_cmd *cmd, struct iscsi_conn *conn)
{
        struct isert_cmd *isert_cmd = container_of(cmd,
                                struct isert_cmd, iscsi_cmd);
        struct isert_conn *isert_conn = (struct isert_conn *)conn->context;
        struct ib_send_wr *send_wr = &isert_cmd->tx_desc.send_wr;

        isert_create_send_desc(isert_conn, isert_cmd, &isert_cmd->tx_desc);
        iscsit_build_reject(cmd, conn, (struct iscsi_reject *)
                                &isert_cmd->tx_desc.iscsi_header);
        isert_init_tx_hdrs(isert_conn, &isert_cmd->tx_desc);
        isert_init_send_wr(isert_cmd, send_wr);

        pr_debug("Posting Reject IB_WR_SEND >>>>>>>>>>>>>>>>>>>>>>\n");

        return isert_post_response(isert_conn, isert_cmd);
}

static int
isert_build_rdma_wr(struct isert_conn *isert_conn, struct isert_cmd *isert_cmd,
                    struct ib_sge *ib_sge, struct ib_send_wr *send_wr,
                    u32 data_left, u32 offset)
{
        struct iscsi_cmd *cmd = &isert_cmd->iscsi_cmd;
        struct scatterlist *sg_start, *tmp_sg;
        struct ib_device *ib_dev = isert_conn->conn_cm_id->device;
        u32 sg_off, page_off;
        int i = 0, sg_nents;

        sg_off = offset / PAGE_SIZE;
        sg_start = &cmd->se_cmd.t_data_sg[sg_off];
        sg_nents = min(cmd->se_cmd.t_data_nents - sg_off, isert_conn->max_sge);
        page_off = offset % PAGE_SIZE;

        send_wr->sg_list = ib_sge;
        send_wr->num_sge = sg_nents;
        send_wr->wr_id = (unsigned long)&isert_cmd->tx_desc;
        /*
         * Perform mapping of TCM scatterlist memory ib_sge dma_addr.
         */
        for_each_sg(sg_start, tmp_sg, sg_nents, i) {
                pr_debug("ISER RDMA from SGL dma_addr: 0x%16llx dma_len: %u, page_off: %u\n",
                         (unsigned long long)tmp_sg->dma_address,
                         tmp_sg->length, page_off);

                ib_sge->addr = ib_sg_dma_address(ib_dev, tmp_sg) + page_off;
                ib_sge->length = min_t(u32, data_left,
                                ib_sg_dma_len(ib_dev, tmp_sg) - page_off);
                ib_sge->lkey = isert_conn->conn_mr->lkey;

                pr_debug("RDMA ib_sge: addr: 0x%16llx  length: %u\n",
                         ib_sge->addr, ib_sge->length);
                page_off = 0;
                data_left -= ib_sge->length;
                ib_sge++;
                pr_debug("Incrementing ib_sge pointer to %p\n", ib_sge);
        }

        pr_debug("Set outgoing sg_list: %p num_sg: %u from TCM SGLs\n",
                 send_wr->sg_list, send_wr->num_sge);

        return sg_nents;
}

static int
isert_put_datain(struct iscsi_conn *conn, struct iscsi_cmd *cmd)
{
        struct se_cmd *se_cmd = &cmd->se_cmd;
        struct isert_cmd *isert_cmd = container_of(cmd,
                                        struct isert_cmd, iscsi_cmd);
        struct isert_rdma_wr *wr = &isert_cmd->rdma_wr;
        struct isert_conn *isert_conn = (struct isert_conn *)conn->context;
        struct ib_send_wr *wr_failed, *send_wr;
        struct ib_device *ib_dev = isert_conn->conn_cm_id->device;
        struct ib_sge *ib_sge;
        struct scatterlist *sg;
        u32 offset = 0, data_len, data_left, rdma_write_max;
        int rc, ret = 0, count, sg_nents, i, ib_sge_cnt;

        pr_debug("RDMA_WRITE: data_length: %u\n", se_cmd->data_length);

        sg = &se_cmd->t_data_sg[0];
        sg_nents = se_cmd->t_data_nents;

        count = ib_dma_map_sg(ib_dev, sg, sg_nents, DMA_TO_DEVICE);
        if (unlikely(!count)) {
                pr_err("Unable to map put_datain SGs\n");
                return -EINVAL;
        }
        wr->sge = sg;
        wr->num_sge = sg_nents;
        pr_debug("Mapped IB count: %u sg: %p sg_nents: %u for RDMA_WRITE\n",
                 count, sg, sg_nents);

        ib_sge = kzalloc(sizeof(struct ib_sge) * sg_nents, GFP_KERNEL);
        if (!ib_sge) {
                pr_warn("Unable to allocate datain ib_sge\n");
                ret = -ENOMEM;
                goto unmap_sg;
        }
        isert_cmd->ib_sge = ib_sge;

        pr_debug("Allocated ib_sge: %p from t_data_ents: %d for RDMA_WRITE\n",
                 ib_sge, se_cmd->t_data_nents);

        wr->send_wr_num = DIV_ROUND_UP(sg_nents, isert_conn->max_sge);
        wr->send_wr = kzalloc(sizeof(struct ib_send_wr) * wr->send_wr_num,
                                GFP_KERNEL);
        if (!wr->send_wr) {
                pr_err("Unable to allocate wr->send_wr\n");
                ret = -ENOMEM;
                goto unmap_sg;
        }
        pr_debug("Allocated wr->send_wr: %p wr->send_wr_num: %u\n",
                 wr->send_wr, wr->send_wr_num);

        iscsit_increment_maxcmdsn(cmd, conn->sess);
        cmd->stat_sn = conn->stat_sn++;

        wr->isert_cmd = isert_cmd;
        rdma_write_max = isert_conn->max_sge * PAGE_SIZE;
        data_left = se_cmd->data_length;

        for (i = 0; i < wr->send_wr_num; i++) {
                send_wr = &isert_cmd->rdma_wr.send_wr[i];
                data_len = min(data_left, rdma_write_max);

                send_wr->opcode = IB_WR_RDMA_WRITE;
                send_wr->send_flags = 0;
                send_wr->wr.rdma.remote_addr = isert_cmd->read_va + offset;
                send_wr->wr.rdma.rkey = isert_cmd->read_stag;

                ib_sge_cnt = isert_build_rdma_wr(isert_conn, isert_cmd, ib_sge,
                                        send_wr, data_len, offset);
                ib_sge += ib_sge_cnt;

                if (i + 1 == wr->send_wr_num)
                        send_wr->next = &isert_cmd->tx_desc.send_wr;
                else
                        send_wr->next = &wr->send_wr[i + 1];

                offset += data_len;
                data_left -= data_len;
        }
        /*
         * Build isert_conn->tx_desc for iSCSI response PDU and attach
         */
        isert_create_send_desc(isert_conn, isert_cmd, &isert_cmd->tx_desc);
        iscsit_build_rsp_pdu(cmd, conn, false, (struct iscsi_scsi_rsp *)
                             &isert_cmd->tx_desc.iscsi_header);
        isert_init_tx_hdrs(isert_conn, &isert_cmd->tx_desc);
        isert_init_send_wr(isert_cmd, &isert_cmd->tx_desc.send_wr);

        atomic_inc(&isert_conn->post_send_buf_count);

        rc = ib_post_send(isert_conn->conn_qp, wr->send_wr, &wr_failed);
        if (rc) {
                pr_warn("ib_post_send() failed for IB_WR_RDMA_WRITE\n");
                atomic_dec(&isert_conn->post_send_buf_count);
        }
        pr_debug("Posted RDMA_WRITE + Response for iSER Data READ\n");
        return 1;

unmap_sg:
        ib_dma_unmap_sg(ib_dev, sg, sg_nents, DMA_TO_DEVICE);
        return ret;
}

static int
isert_get_dataout(struct iscsi_conn *conn, struct iscsi_cmd *cmd, bool recovery)
{
        struct se_cmd *se_cmd = &cmd->se_cmd;
        struct isert_cmd *isert_cmd = container_of(cmd,
                                        struct isert_cmd, iscsi_cmd);
        struct isert_rdma_wr *wr = &isert_cmd->rdma_wr;
        struct isert_conn *isert_conn = (struct isert_conn *)conn->context;
        struct ib_send_wr *wr_failed, *send_wr;
        struct ib_sge *ib_sge;
        struct ib_device *ib_dev = isert_conn->conn_cm_id->device;
        struct scatterlist *sg_start;
        u32 sg_off, sg_nents, page_off, va_offset = 0;
        u32 offset = 0, data_len, data_left, rdma_write_max;
        int rc, ret = 0, count, i, ib_sge_cnt;

        pr_debug("RDMA_READ: data_length: %u write_data_done: %u\n",
                 se_cmd->data_length, cmd->write_data_done);

        sg_off = cmd->write_data_done / PAGE_SIZE;
        sg_start = &cmd->se_cmd.t_data_sg[sg_off];
        page_off = cmd->write_data_done % PAGE_SIZE;

        pr_debug("RDMA_READ: sg_off: %d, sg_start: %p page_off: %d\n",
                 sg_off, sg_start, page_off);

        data_left = se_cmd->data_length - cmd->write_data_done;
        sg_nents = se_cmd->t_data_nents - sg_off;

        pr_debug("RDMA_READ: data_left: %d, sg_nents: %d\n",
                 data_left, sg_nents);

        count = ib_dma_map_sg(ib_dev, sg_start, sg_nents, DMA_FROM_DEVICE);
        if (unlikely(!count)) {
                pr_err("Unable to map get_dataout SGs\n");
                return -EINVAL;
        }
        wr->sge = sg_start;
        wr->num_sge = sg_nents;
        pr_debug("Mapped IB count: %u sg_start: %p sg_nents: %u for RDMA_READ\n",
                 count, sg_start, sg_nents);

        ib_sge = kzalloc(sizeof(struct ib_sge) * sg_nents, GFP_KERNEL);
        if (!ib_sge) {
                pr_warn("Unable to allocate dataout ib_sge\n");
                ret = -ENOMEM;
                goto unmap_sg;
        }
        isert_cmd->ib_sge = ib_sge;

        pr_debug("Using ib_sge: %p from sg_ents: %d for RDMA_READ\n",
                 ib_sge, sg_nents);

        wr->send_wr_num = DIV_ROUND_UP(sg_nents, isert_conn->max_sge);
        wr->send_wr = kzalloc(sizeof(struct ib_send_wr) * wr->send_wr_num,
                                GFP_KERNEL);
        if (!wr->send_wr) {
                pr_debug("Unable to allocate wr->send_wr\n");
                ret = -ENOMEM;
                goto unmap_sg;
        }
        pr_debug("Allocated wr->send_wr: %p wr->send_wr_num: %u\n",
                 wr->send_wr, wr->send_wr_num);

        isert_cmd->tx_desc.isert_cmd = isert_cmd;

        wr->iser_ib_op = ISER_IB_RDMA_READ;
        wr->isert_cmd = isert_cmd;
        rdma_write_max = isert_conn->max_sge * PAGE_SIZE;
        offset = cmd->write_data_done;

        for (i = 0; i < wr->send_wr_num; i++) {
                send_wr = &isert_cmd->rdma_wr.send_wr[i];
                data_len = min(data_left, rdma_write_max);

                send_wr->opcode = IB_WR_RDMA_READ;
                send_wr->wr.rdma.remote_addr = isert_cmd->write_va + va_offset;
                send_wr->wr.rdma.rkey = isert_cmd->write_stag;

                ib_sge_cnt = isert_build_rdma_wr(isert_conn, isert_cmd, ib_sge,
                                        send_wr, data_len, offset);
                ib_sge += ib_sge_cnt;

                if (i + 1 == wr->send_wr_num)
                        send_wr->send_flags = IB_SEND_SIGNALED;
                else
                        send_wr->next = &wr->send_wr[i + 1];

                offset += data_len;
                va_offset += data_len;
                data_left -= data_len;
        }

        atomic_inc(&isert_conn->post_send_buf_count);

        rc = ib_post_send(isert_conn->conn_qp, wr->send_wr, &wr_failed);
        if (rc) {
                pr_warn("ib_post_send() failed for IB_WR_RDMA_READ\n");
                atomic_dec(&isert_conn->post_send_buf_count);
        }
        pr_debug("Posted RDMA_READ memory for ISER Data WRITE\n");
        return 0;

unmap_sg:
        ib_dma_unmap_sg(ib_dev, sg_start, sg_nents, DMA_FROM_DEVICE);
        return ret;
}

static int
isert_immediate_queue(struct iscsi_conn *conn, struct iscsi_cmd *cmd, int state)
{
        int ret;

        switch (state) {
        case ISTATE_SEND_NOPIN_WANT_RESPONSE:
                ret = isert_put_nopin(cmd, conn, false);
                break;
        default:
                pr_err("Unknown immediate state: 0x%02x\n", state);
                ret = -EINVAL;
                break;
        }

        return ret;
}

static int
isert_response_queue(struct iscsi_conn *conn, struct iscsi_cmd *cmd, int state)
{
        int ret;

        switch (state) {
        case ISTATE_SEND_LOGOUTRSP:
                ret = isert_put_logout_rsp(cmd, conn);
                if (!ret) {
                        pr_debug("Returning iSER Logout -EAGAIN\n");
                        ret = -EAGAIN;
                }
                break;
        case ISTATE_SEND_NOPIN:
                ret = isert_put_nopin(cmd, conn, true);
                break;
        case ISTATE_SEND_TASKMGTRSP:
                ret = isert_put_tm_rsp(cmd, conn);
                break;
        case ISTATE_SEND_REJECT:
                ret = isert_put_reject(cmd, conn);
                break;
        case ISTATE_SEND_STATUS:
                /*
                 * Special case for sending non GOOD SCSI status from TX thread
                 * context during pre se_cmd excecution failure.
                 */
                ret = isert_put_response(conn, cmd);
                break;
        default:
                pr_err("Unknown response state: 0x%02x\n", state);
                ret = -EINVAL;
                break;
        }

        return ret;
}

static int
isert_setup_np(struct iscsi_np *np,
               struct __kernel_sockaddr_storage *ksockaddr)
{
        struct isert_np *isert_np;
        struct rdma_cm_id *isert_lid;
        struct sockaddr *sa;
        int ret;

        isert_np = kzalloc(sizeof(struct isert_np), GFP_KERNEL);
        if (!isert_np) {
                pr_err("Unable to allocate struct isert_np\n");
                return -ENOMEM;
        }
        init_waitqueue_head(&isert_np->np_accept_wq);
        mutex_init(&isert_np->np_accept_mutex);
        INIT_LIST_HEAD(&isert_np->np_accept_list);
        init_completion(&isert_np->np_login_comp);

        sa = (struct sockaddr *)ksockaddr;
        pr_debug("ksockaddr: %p, sa: %p\n", ksockaddr, sa);
        /*
         * Setup the np->np_sockaddr from the passed sockaddr setup
         * in iscsi_target_configfs.c code..
         */
        memcpy(&np->np_sockaddr, ksockaddr,
               sizeof(struct __kernel_sockaddr_storage));

        isert_lid = rdma_create_id(isert_cma_handler, np, RDMA_PS_TCP,
                                IB_QPT_RC);
        if (IS_ERR(isert_lid)) {
                pr_err("rdma_create_id() for isert_listen_handler failed: %ld\n",
                       PTR_ERR(isert_lid));
                ret = PTR_ERR(isert_lid);
                goto out;

        }

        ret = rdma_bind_addr(isert_lid, sa);
        if (ret) {
                pr_err("rdma_bind_addr() for isert_lid failed: %d\n", ret);
                goto out_lid;
        }

        ret = rdma_listen(isert_lid, ISERT_RDMA_LISTEN_BACKLOG);
        if (ret) {
                pr_err("rdma_listen() for isert_lid failed: %d\n", ret);
                goto out_lid;
        }

        isert_np->np_cm_id = isert_lid;
        np->np_context = isert_np;
        pr_debug("Setup isert_lid->context: %p\n", isert_lid->context);

        return 0;

out_lid:
        rdma_destroy_id(isert_lid);
out:
        kfree(isert_np);
        return ret;
}

static int
isert_check_accept_queue(struct isert_np *isert_np)
{
        int empty;

        mutex_lock(&isert_np->np_accept_mutex);
        empty = list_empty(&isert_np->np_accept_list);
        mutex_unlock(&isert_np->np_accept_mutex);

        return empty;
}

static int
isert_rdma_accept(struct isert_conn *isert_conn)
{
        struct rdma_cm_id *cm_id = isert_conn->conn_cm_id;
        struct rdma_conn_param cp;
        int ret;

        memset(&cp, 0, sizeof(struct rdma_conn_param));
        cp.responder_resources = isert_conn->responder_resources;
        cp.initiator_depth = isert_conn->initiator_depth;
        cp.retry_count = 7;
        cp.rnr_retry_count = 7;

        pr_debug("Before rdma_accept >>>>>>>>>>>>>>>>>>>>.\n");

        ret = rdma_accept(cm_id, &cp);
        if (ret) {
                pr_err("rdma_accept() failed with: %d\n", ret);
                return ret;
        }

        pr_debug("After rdma_accept >>>>>>>>>>>>>>>>>>>>>.\n");

        return 0;
}

static int
isert_get_login_rx(struct iscsi_conn *conn, struct iscsi_login *login)
{
        struct isert_conn *isert_conn = (struct isert_conn *)conn->context;
        int ret;

        pr_debug("isert_get_login_rx before conn_login_comp conn: %p\n", conn);

        ret = wait_for_completion_interruptible(&isert_conn->conn_login_comp);
        if (ret)
                return ret;

        pr_debug("isert_get_login_rx processing login->req: %p\n", login->req);
        return 0;
}

static void
isert_set_conn_info(struct iscsi_np *np, struct iscsi_conn *conn,
                    struct isert_conn *isert_conn)
{
        struct rdma_cm_id *cm_id = isert_conn->conn_cm_id;
        struct rdma_route *cm_route = &cm_id->route;
        struct sockaddr_in *sock_in;
        struct sockaddr_in6 *sock_in6;

        conn->login_family = np->np_sockaddr.ss_family;

        if (np->np_sockaddr.ss_family == AF_INET6) {
                sock_in6 = (struct sockaddr_in6 *)&cm_route->addr.dst_addr;
                snprintf(conn->login_ip, sizeof(conn->login_ip), "%pI6c",
                         &sock_in6->sin6_addr.in6_u);
                conn->login_port = ntohs(sock_in6->sin6_port);

                sock_in6 = (struct sockaddr_in6 *)&cm_route->addr.src_addr;
                snprintf(conn->local_ip, sizeof(conn->local_ip), "%pI6c",
                         &sock_in6->sin6_addr.in6_u);
                conn->local_port = ntohs(sock_in6->sin6_port);
        } else {
                sock_in = (struct sockaddr_in *)&cm_route->addr.dst_addr;
                sprintf(conn->login_ip, "%pI4",
                        &sock_in->sin_addr.s_addr);
                conn->login_port = ntohs(sock_in->sin_port);

                sock_in = (struct sockaddr_in *)&cm_route->addr.src_addr;
                sprintf(conn->local_ip, "%pI4",
                        &sock_in->sin_addr.s_addr);
                conn->local_port = ntohs(sock_in->sin_port);
        }
}

static int
isert_accept_np(struct iscsi_np *np, struct iscsi_conn *conn)
{
        struct isert_np *isert_np = (struct isert_np *)np->np_context;
        struct isert_conn *isert_conn;
        int max_accept = 0, ret;

accept_wait:
        ret = wait_event_interruptible(isert_np->np_accept_wq,
                        !isert_check_accept_queue(isert_np) ||
                        np->np_thread_state == ISCSI_NP_THREAD_RESET);
        if (max_accept > 5)
                return -ENODEV;

        spin_lock_bh(&np->np_thread_lock);
        if (np->np_thread_state == ISCSI_NP_THREAD_RESET) {
                spin_unlock_bh(&np->np_thread_lock);
                pr_err("ISCSI_NP_THREAD_RESET for isert_accept_np\n");
                return -ENODEV;
        }
        spin_unlock_bh(&np->np_thread_lock);

        mutex_lock(&isert_np->np_accept_mutex);
        if (list_empty(&isert_np->np_accept_list)) {
                mutex_unlock(&isert_np->np_accept_mutex);
                max_accept++;
                goto accept_wait;
        }
        isert_conn = list_first_entry(&isert_np->np_accept_list,
                        struct isert_conn, conn_accept_node);
        list_del_init(&isert_conn->conn_accept_node);
        mutex_unlock(&isert_np->np_accept_mutex);

        conn->context = isert_conn;
        isert_conn->conn = conn;
        max_accept = 0;

        ret = isert_rdma_post_recvl(isert_conn);
        if (ret)
                return ret;

        ret = isert_rdma_accept(isert_conn);
        if (ret)
                return ret;

        isert_set_conn_info(np, conn, isert_conn);

        pr_debug("Processing isert_accept_np: isert_conn: %p\n", isert_conn);
        return 0;
}

static void
isert_free_np(struct iscsi_np *np)
{
        struct isert_np *isert_np = (struct isert_np *)np->np_context;

        rdma_destroy_id(isert_np->np_cm_id);

        np->np_context = NULL;
        kfree(isert_np);
}

static void isert_free_conn(struct iscsi_conn *conn)
{
        struct isert_conn *isert_conn = conn->context;

        pr_debug("isert_free_conn: Starting \n");
        /*
         * Decrement post_send_buf_count for special case when called
         * from isert_do_control_comp() -> iscsit_logout_post_handler()
         */
        if (isert_conn->logout_posted)
                atomic_dec(&isert_conn->post_send_buf_count);

        if (isert_conn->conn_cm_id)
                rdma_disconnect(isert_conn->conn_cm_id);
        /*
         * Only wait for conn_wait_comp_err if the isert_conn made it
         * into full feature phase..
         */
        if (isert_conn->state > ISER_CONN_INIT) {
                pr_debug("isert_free_conn: Before wait_event comp_err %d\n",
                         isert_conn->state);
                wait_event(isert_conn->conn_wait_comp_err,
                           isert_conn->state == ISER_CONN_TERMINATING);
                pr_debug("isert_free_conn: After wait_event #1 >>>>>>>>>>>>\n");
        }

        pr_debug("isert_free_conn: wait_event conn_wait %d\n", isert_conn->state);
        wait_event(isert_conn->conn_wait, isert_conn->state == ISER_CONN_DOWN);
        pr_debug("isert_free_conn: After wait_event #2 >>>>>>>>>>>>>>>>>>>>\n");

        isert_put_conn(isert_conn);
}

static struct iscsit_transport iser_target_transport = {
        .name                   = "IB/iSER",
        .transport_type         = ISCSI_INFINIBAND,
        .owner                  = THIS_MODULE,
        .iscsit_setup_np        = isert_setup_np,
        .iscsit_accept_np       = isert_accept_np,
        .iscsit_free_np         = isert_free_np,
        .iscsit_free_conn       = isert_free_conn,
        .iscsit_alloc_cmd       = isert_alloc_cmd,
        .iscsit_get_login_rx    = isert_get_login_rx,
        .iscsit_put_login_tx    = isert_put_login_tx,
        .iscsit_immediate_queue = isert_immediate_queue,
        .iscsit_response_queue  = isert_response_queue,
        .iscsit_get_dataout     = isert_get_dataout,
        .iscsit_queue_data_in   = isert_put_datain,
        .iscsit_queue_status    = isert_put_response,
};

static int __init isert_init(void)
{
        int ret;

        isert_rx_wq = alloc_workqueue("isert_rx_wq", 0, 0);
        if (!isert_rx_wq) {
                pr_err("Unable to allocate isert_rx_wq\n");
                return -ENOMEM;
        }

        isert_comp_wq = alloc_workqueue("isert_comp_wq", 0, 0);
        if (!isert_comp_wq) {
                pr_err("Unable to allocate isert_comp_wq\n");
                ret = -ENOMEM;
                goto destroy_rx_wq;
        }

        isert_cmd_cache = kmem_cache_create("isert_cmd_cache",
                        sizeof(struct isert_cmd), __alignof__(struct isert_cmd),
                        0, NULL);
        if (!isert_cmd_cache) {
                pr_err("Unable to create isert_cmd_cache\n");
                ret = -ENOMEM;
                goto destroy_tx_cq;
        }

        iscsit_register_transport(&iser_target_transport);
        pr_debug("iSER_TARGET[0] - Loaded iser_target_transport\n");
        return 0;

destroy_tx_cq:
        destroy_workqueue(isert_comp_wq);
destroy_rx_wq:
        destroy_workqueue(isert_rx_wq);
        return ret;
}

static void __exit isert_exit(void)
{
        kmem_cache_destroy(isert_cmd_cache);
        destroy_workqueue(isert_comp_wq);
        destroy_workqueue(isert_rx_wq);
        iscsit_unregister_transport(&iser_target_transport);
        pr_debug("iSER_TARGET[0] - Released iser_target_transport\n");
}

MODULE_DESCRIPTION("iSER-Target for mainline target infrastructure");
MODULE_VERSION("0.1");
MODULE_AUTHOR("nab@Linux-iSCSI.org");
MODULE_LICENSE("GPL");

module_init(isert_init);
module_exit(isert_exit);