/*******************************************************************************
 * This file contains iSCSI extentions for RDMA (iSER) Verbs
 *
 * (c) Copyright 2013 Datera, Inc.
 *
 * 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 <linux/semaphore.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)
#define ISER_MAX_CQ_LEN         (ISER_MAX_RX_CQ_LEN + ISER_MAX_TX_CQ_LEN + \
                                 ISERT_MAX_CONN)

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

static DEFINE_MUTEX(device_list_mutex);
static LIST_HEAD(device_list);
static struct workqueue_struct *isert_comp_wq;
static struct workqueue_struct *isert_release_wq;

static void
isert_unmap_cmd(struct isert_cmd *isert_cmd, struct isert_conn *isert_conn);
static int
isert_map_rdma(struct iscsi_conn *conn, struct iscsi_cmd *cmd,
               struct isert_rdma_wr *wr);
static void
isert_unreg_rdma(struct isert_cmd *isert_cmd, struct isert_conn *isert_conn);
static int
isert_reg_rdma(struct iscsi_conn *conn, struct iscsi_cmd *cmd,
               struct isert_rdma_wr *wr);
static int
isert_put_response(struct iscsi_conn *conn, struct iscsi_cmd *cmd);
static int
isert_rdma_post_recvl(struct isert_conn *isert_conn);
static int
isert_rdma_accept(struct isert_conn *isert_conn);
struct rdma_cm_id *isert_setup_id(struct isert_np *isert_np);

static void isert_release_work(struct work_struct *work);

static inline bool
isert_prot_cmd(struct isert_conn *conn, struct se_cmd *cmd)
{
        return (conn->pi_support &&
                cmd->prot_op != TARGET_PROT_NORMAL);
}


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

        isert_err("%s (%d): conn %p\n",
                  ib_event_msg(e->event), e->event, isert_conn);

        switch (e->event) {
        case IB_EVENT_COMM_EST:
                rdma_notify(isert_conn->cm_id, IB_EVENT_COMM_EST);
                break;
        case IB_EVENT_QP_LAST_WQE_REACHED:
                isert_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) {
                isert_err("ib_query_device() failed: %d\n", ret);
                return ret;
        }
        isert_dbg("devattr->max_sge: %d\n", devattr->max_sge);
        isert_dbg("devattr->max_sge_rd: %d\n", devattr->max_sge_rd);

        return 0;
}

static struct isert_comp *
isert_comp_get(struct isert_conn *isert_conn)
{
        struct isert_device *device = isert_conn->device;
        struct isert_comp *comp;
        int i, min = 0;

        mutex_lock(&device_list_mutex);
        for (i = 0; i < device->comps_used; i++)
                if (device->comps[i].active_qps <
                    device->comps[min].active_qps)
                        min = i;
        comp = &device->comps[min];
        comp->active_qps++;
        mutex_unlock(&device_list_mutex);

        isert_info("conn %p, using comp %p min_index: %d\n",
                   isert_conn, comp, min);

        return comp;
}

static void
isert_comp_put(struct isert_comp *comp)
{
        mutex_lock(&device_list_mutex);
        comp->active_qps--;
        mutex_unlock(&device_list_mutex);
}

static struct ib_qp *
isert_create_qp(struct isert_conn *isert_conn,
                struct isert_comp *comp,
                struct rdma_cm_id *cma_id)
{
        struct isert_device *device = isert_conn->device;
        struct ib_qp_init_attr attr;
        int ret;

        memset(&attr, 0, sizeof(struct ib_qp_init_attr));
        attr.event_handler = isert_qp_event_callback;
        attr.qp_context = isert_conn;
        attr.send_cq = comp->cq;
        attr.recv_cq = comp->cq;
        attr.cap.max_send_wr = ISERT_QP_MAX_REQ_DTOS;
        attr.cap.max_recv_wr = ISERT_QP_MAX_RECV_DTOS + 1;
        /*
         * FIXME: Use devattr.max_sge - 2 for max_send_sge as
         * work-around for RDMA_READs with ConnectX-2.
         *
         * Also, still make sure to have at least two SGEs for
         * outgoing control PDU responses.
         */
        attr.cap.max_send_sge = max(2, device->dev_attr.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;
        if (device->pi_capable)
                attr.create_flags |= IB_QP_CREATE_SIGNATURE_EN;

        ret = rdma_create_qp(cma_id, device->pd, &attr);
        if (ret) {
                isert_err("rdma_create_qp failed for cma_id %d\n", ret);
                return ERR_PTR(ret);
        }

        return cma_id->qp;
}

static int
isert_conn_setup_qp(struct isert_conn *isert_conn, struct rdma_cm_id *cma_id)
{
        struct isert_comp *comp;
        int ret;

        comp = isert_comp_get(isert_conn);
        isert_conn->qp = isert_create_qp(isert_conn, comp, cma_id);
        if (IS_ERR(isert_conn->qp)) {
                ret = PTR_ERR(isert_conn->qp);
                goto err;
        }

        return 0;
err:
        isert_comp_put(comp);
        return ret;
}

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

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

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

        rx_desc = isert_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 = device->mr->lkey;
        }

        isert_conn->rx_desc_head = 0;

        return 0;

dma_map_fail:
        rx_desc = isert_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->rx_descs);
        isert_conn->rx_descs = NULL;
fail:
        isert_err("conn %p failed to allocate rx descriptors\n", isert_conn);

        return -ENOMEM;
}

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

        if (!isert_conn->rx_descs)
                return;

        rx_desc = isert_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->rx_descs);
        isert_conn->rx_descs = NULL;
}

static void isert_cq_work(struct work_struct *);
static void isert_cq_callback(struct ib_cq *, void *);

static void
isert_free_comps(struct isert_device *device)
{
        int i;

        for (i = 0; i < device->comps_used; i++) {
                struct isert_comp *comp = &device->comps[i];

                if (comp->cq) {
                        cancel_work_sync(&comp->work);
                        ib_destroy_cq(comp->cq);
                }
        }
        kfree(device->comps);
}

static int
isert_alloc_comps(struct isert_device *device,
                  struct ib_device_attr *attr)
{
        int i, max_cqe, ret = 0;

        device->comps_used = min(ISERT_MAX_CQ, min_t(int, num_online_cpus(),
                                 device->ib_device->num_comp_vectors));

        isert_info("Using %d CQs, %s supports %d vectors support "
                   "Fast registration %d pi_capable %d\n",
                   device->comps_used, device->ib_device->name,
                   device->ib_device->num_comp_vectors, device->use_fastreg,
                   device->pi_capable);

        device->comps = kcalloc(device->comps_used, sizeof(struct isert_comp),
                                GFP_KERNEL);
        if (!device->comps) {
                isert_err("Unable to allocate completion contexts\n");
                return -ENOMEM;
        }

        max_cqe = min(ISER_MAX_CQ_LEN, attr->max_cqe);

        for (i = 0; i < device->comps_used; i++) {
                struct ib_cq_init_attr cq_attr = {};
                struct isert_comp *comp = &device->comps[i];

                comp->device = device;
                INIT_WORK(&comp->work, isert_cq_work);
                cq_attr.cqe = max_cqe;
                cq_attr.comp_vector = i;
                comp->cq = ib_create_cq(device->ib_device,
                                        isert_cq_callback,
                                        isert_cq_event_callback,
                                        (void *)comp,
                                        &cq_attr);
                if (IS_ERR(comp->cq)) {
                        isert_err("Unable to allocate cq\n");
                        ret = PTR_ERR(comp->cq);
                        comp->cq = NULL;
                        goto out_cq;
                }

                ret = ib_req_notify_cq(comp->cq, IB_CQ_NEXT_COMP);
                if (ret)
                        goto out_cq;
        }

        return 0;
out_cq:
        isert_free_comps(device);
        return ret;
}

static int
isert_create_device_ib_res(struct isert_device *device)
{
        struct ib_device_attr *dev_attr;
        int ret;

        dev_attr = &device->dev_attr;
        ret = isert_query_device(device->ib_device, dev_attr);
        if (ret)
                return ret;

        /* asign function handlers */
        if (dev_attr->device_cap_flags & IB_DEVICE_MEM_MGT_EXTENSIONS &&
            dev_attr->device_cap_flags & IB_DEVICE_SIGNATURE_HANDOVER) {
                device->use_fastreg = 1;
                device->reg_rdma_mem = isert_reg_rdma;
                device->unreg_rdma_mem = isert_unreg_rdma;
        } else {
                device->use_fastreg = 0;
                device->reg_rdma_mem = isert_map_rdma;
                device->unreg_rdma_mem = isert_unmap_cmd;
        }

        ret = isert_alloc_comps(device, dev_attr);
        if (ret)
                return ret;

        device->pd = ib_alloc_pd(device->ib_device);
        if (IS_ERR(device->pd)) {
                ret = PTR_ERR(device->pd);
                isert_err("failed to allocate pd, device %p, ret=%d\n",
                          device, ret);
                goto out_cq;
        }

        device->mr = ib_get_dma_mr(device->pd, IB_ACCESS_LOCAL_WRITE);
        if (IS_ERR(device->mr)) {
                ret = PTR_ERR(device->mr);
                isert_err("failed to create dma mr, device %p, ret=%d\n",
                          device, ret);
                goto out_mr;
        }

        /* Check signature cap */
        device->pi_capable = dev_attr->device_cap_flags &
                             IB_DEVICE_SIGNATURE_HANDOVER ? true : false;

        return 0;

out_mr:
        ib_dealloc_pd(device->pd);
out_cq:
        isert_free_comps(device);
        return ret;
}

static void
isert_free_device_ib_res(struct isert_device *device)
{
        isert_info("device %p\n", device);

        ib_dereg_mr(device->mr);
        ib_dealloc_pd(device->pd);
        isert_free_comps(device);
}

static void
isert_device_put(struct isert_device *device)
{
        mutex_lock(&device_list_mutex);
        device->refcount--;
        isert_info("device %p refcount %d\n", device, 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_get(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++;
                        isert_info("Found iser device %p refcount %d\n",
                                   device, 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);
        isert_info("Created a new iser device %p refcount %d\n",
                   device, device->refcount);
        mutex_unlock(&device_list_mutex);

        return device;
}

static void
isert_conn_free_fastreg_pool(struct isert_conn *isert_conn)
{
        struct fast_reg_descriptor *fr_desc, *tmp;
        int i = 0;

        if (list_empty(&isert_conn->fr_pool))
                return;

        isert_info("Freeing conn %p fastreg pool", isert_conn);

        list_for_each_entry_safe(fr_desc, tmp,
                                 &isert_conn->fr_pool, list) {
                list_del(&fr_desc->list);
                ib_free_fast_reg_page_list(fr_desc->data_frpl);
                ib_dereg_mr(fr_desc->data_mr);
                if (fr_desc->pi_ctx) {
                        ib_free_fast_reg_page_list(fr_desc->pi_ctx->prot_frpl);
                        ib_dereg_mr(fr_desc->pi_ctx->prot_mr);
                        ib_destroy_mr(fr_desc->pi_ctx->sig_mr);
                        kfree(fr_desc->pi_ctx);
                }
                kfree(fr_desc);
                ++i;
        }

        if (i < isert_conn->fr_pool_size)
                isert_warn("Pool still has %d regions registered\n",
                        isert_conn->fr_pool_size - i);
}

static int
isert_create_pi_ctx(struct fast_reg_descriptor *desc,
                    struct ib_device *device,
                    struct ib_pd *pd)
{
        struct ib_mr_init_attr mr_init_attr;
        struct pi_context *pi_ctx;
        int ret;

        pi_ctx = kzalloc(sizeof(*desc->pi_ctx), GFP_KERNEL);
        if (!pi_ctx) {
                isert_err("Failed to allocate pi context\n");
                return -ENOMEM;
        }

        pi_ctx->prot_frpl = ib_alloc_fast_reg_page_list(device,
                                            ISCSI_ISER_SG_TABLESIZE);
        if (IS_ERR(pi_ctx->prot_frpl)) {
                isert_err("Failed to allocate prot frpl err=%ld\n",
                          PTR_ERR(pi_ctx->prot_frpl));
                ret = PTR_ERR(pi_ctx->prot_frpl);
                goto err_pi_ctx;
        }

        pi_ctx->prot_mr = ib_alloc_fast_reg_mr(pd, ISCSI_ISER_SG_TABLESIZE);
        if (IS_ERR(pi_ctx->prot_mr)) {
                isert_err("Failed to allocate prot frmr err=%ld\n",
                          PTR_ERR(pi_ctx->prot_mr));
                ret = PTR_ERR(pi_ctx->prot_mr);
                goto err_prot_frpl;
        }
        desc->ind |= ISERT_PROT_KEY_VALID;

        memset(&mr_init_attr, 0, sizeof(mr_init_attr));
        mr_init_attr.max_reg_descriptors = 2;
        mr_init_attr.flags |= IB_MR_SIGNATURE_EN;
        pi_ctx->sig_mr = ib_create_mr(pd, &mr_init_attr);
        if (IS_ERR(pi_ctx->sig_mr)) {
                isert_err("Failed to allocate signature enabled mr err=%ld\n",
                          PTR_ERR(pi_ctx->sig_mr));
                ret = PTR_ERR(pi_ctx->sig_mr);
                goto err_prot_mr;
        }

        desc->pi_ctx = pi_ctx;
        desc->ind |= ISERT_SIG_KEY_VALID;
        desc->ind &= ~ISERT_PROTECTED;

        return 0;

err_prot_mr:
        ib_dereg_mr(pi_ctx->prot_mr);
err_prot_frpl:
        ib_free_fast_reg_page_list(pi_ctx->prot_frpl);
err_pi_ctx:
        kfree(pi_ctx);

        return ret;
}

static int
isert_create_fr_desc(struct ib_device *ib_device, struct ib_pd *pd,
                     struct fast_reg_descriptor *fr_desc)
{
        int ret;

        fr_desc->data_frpl = ib_alloc_fast_reg_page_list(ib_device,
                                                         ISCSI_ISER_SG_TABLESIZE);
        if (IS_ERR(fr_desc->data_frpl)) {
                isert_err("Failed to allocate data frpl err=%ld\n",
                          PTR_ERR(fr_desc->data_frpl));
                return PTR_ERR(fr_desc->data_frpl);
        }

        fr_desc->data_mr = ib_alloc_fast_reg_mr(pd, ISCSI_ISER_SG_TABLESIZE);
        if (IS_ERR(fr_desc->data_mr)) {
                isert_err("Failed to allocate data frmr err=%ld\n",
                          PTR_ERR(fr_desc->data_mr));
                ret = PTR_ERR(fr_desc->data_mr);
                goto err_data_frpl;
        }
        fr_desc->ind |= ISERT_DATA_KEY_VALID;

        isert_dbg("Created fr_desc %p\n", fr_desc);

        return 0;

err_data_frpl:
        ib_free_fast_reg_page_list(fr_desc->data_frpl);

        return ret;
}

static int
isert_conn_create_fastreg_pool(struct isert_conn *isert_conn)
{
        struct fast_reg_descriptor *fr_desc;
        struct isert_device *device = isert_conn->device;
        struct se_session *se_sess = isert_conn->conn->sess->se_sess;
        struct se_node_acl *se_nacl = se_sess->se_node_acl;
        int i, ret, tag_num;
        /*
         * Setup the number of FRMRs based upon the number of tags
         * available to session in iscsi_target_locate_portal().
         */
        tag_num = max_t(u32, ISCSIT_MIN_TAGS, se_nacl->queue_depth);
        tag_num = (tag_num * 2) + ISCSIT_EXTRA_TAGS;

        isert_conn->fr_pool_size = 0;
        for (i = 0; i < tag_num; i++) {
                fr_desc = kzalloc(sizeof(*fr_desc), GFP_KERNEL);
                if (!fr_desc) {
                        isert_err("Failed to allocate fast_reg descriptor\n");
                        ret = -ENOMEM;
                        goto err;
                }

                ret = isert_create_fr_desc(device->ib_device,
                                           device->pd, fr_desc);
                if (ret) {
                        isert_err("Failed to create fastreg descriptor err=%d\n",
                               ret);
                        kfree(fr_desc);
                        goto err;
                }

                list_add_tail(&fr_desc->list, &isert_conn->fr_pool);
                isert_conn->fr_pool_size++;
        }

        isert_dbg("Creating conn %p fastreg pool size=%d",
                 isert_conn, isert_conn->fr_pool_size);

        return 0;

err:
        isert_conn_free_fastreg_pool(isert_conn);
        return ret;
}

static void
isert_init_conn(struct isert_conn *isert_conn)
{
        isert_conn->state = ISER_CONN_INIT;
        INIT_LIST_HEAD(&isert_conn->accept_node);
        init_completion(&isert_conn->login_comp);
        init_completion(&isert_conn->login_req_comp);
        init_completion(&isert_conn->wait);
        kref_init(&isert_conn->kref);
        mutex_init(&isert_conn->mutex);
        spin_lock_init(&isert_conn->pool_lock);
        INIT_LIST_HEAD(&isert_conn->fr_pool);
        INIT_WORK(&isert_conn->release_work, isert_release_work);
}

static void
isert_free_login_buf(struct isert_conn *isert_conn)
{
        struct ib_device *ib_dev = isert_conn->device->ib_device;

        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);
}

static int
isert_alloc_login_buf(struct isert_conn *isert_conn,
                      struct ib_device *ib_dev)
{
        int ret;

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

        isert_conn->login_req_buf = isert_conn->login_buf;
        isert_conn->login_rsp_buf = isert_conn->login_buf +
                                    ISCSI_DEF_MAX_RECV_SEG_LEN;

        isert_dbg("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) {
                isert_err("login_req_dma mapping error: %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) {
                isert_err("login_rsp_dma mapping error: %d\n", ret);
                isert_conn->login_rsp_dma = 0;
                goto out_req_dma_map;
        }

        return 0;

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);
        return ret;
}

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

        spin_lock_bh(&np->np_thread_lock);
        if (!np->enabled) {
                spin_unlock_bh(&np->np_thread_lock);
                isert_dbg("iscsi_np is not enabled, reject connect request\n");
                return rdma_reject(cma_id, NULL, 0);
        }
        spin_unlock_bh(&np->np_thread_lock);

        isert_dbg("cma_id: %p, portal: %p\n",
                 cma_id, cma_id->context);

        isert_conn = kzalloc(sizeof(struct isert_conn), GFP_KERNEL);
        if (!isert_conn)
                return -ENOMEM;

        isert_init_conn(isert_conn);
        isert_conn->cm_id = cma_id;

        ret = isert_alloc_login_buf(isert_conn, cma_id->device);
        if (ret)
                goto out;

        device = isert_device_get(cma_id);
        if (IS_ERR(device)) {
                ret = PTR_ERR(device);
                goto out_rsp_dma_map;
        }
        isert_conn->device = device;

        /* Set max inflight RDMA READ requests */
        isert_conn->initiator_depth = min_t(u8,
                                event->param.conn.initiator_depth,
                                device->dev_attr.max_qp_init_rd_atom);
        isert_dbg("Using initiator_depth: %u\n", isert_conn->initiator_depth);

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

        ret = isert_rdma_post_recvl(isert_conn);
        if (ret)
                goto out_conn_dev;
        /*
         * Obtain the second reference now before isert_rdma_accept() to
         * ensure that any initiator generated REJECT CM event that occurs
         * asynchronously won't drop the last reference until the error path
         * in iscsi_target_login_sess_out() does it's ->iscsit_free_conn() ->
         * isert_free_conn() -> isert_put_conn() -> kref_put().
         */
        if (!kref_get_unless_zero(&isert_conn->kref)) {
                isert_warn("conn %p connect_release is running\n", isert_conn);
                goto out_conn_dev;
        }

        ret = isert_rdma_accept(isert_conn);
        if (ret)
                goto out_conn_dev;

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

        isert_info("np %p: Allow accept_np to continue\n", np);
        up(&isert_np->np_sem);
        return 0;

out_conn_dev:
        isert_device_put(device);
out_rsp_dma_map:
        isert_free_login_buf(isert_conn);
out:
        kfree(isert_conn);
        rdma_reject(cma_id, NULL, 0);
        return ret;
}

static void
isert_connect_release(struct isert_conn *isert_conn)
{
        struct isert_device *device = isert_conn->device;

        isert_dbg("conn %p\n", isert_conn);

        BUG_ON(!device);

        if (device->use_fastreg)
                isert_conn_free_fastreg_pool(isert_conn);

        isert_free_rx_descriptors(isert_conn);
        if (isert_conn->cm_id)
                rdma_destroy_id(isert_conn->cm_id);

        if (isert_conn->qp) {
                struct isert_comp *comp = isert_conn->qp->recv_cq->cq_context;

                isert_comp_put(comp);
                ib_destroy_qp(isert_conn->qp);
        }

        if (isert_conn->login_buf)
                isert_free_login_buf(isert_conn);

        isert_device_put(device);

        kfree(isert_conn);
}

static void
isert_connected_handler(struct rdma_cm_id *cma_id)
{
        struct isert_conn *isert_conn = cma_id->qp->qp_context;

        isert_info("conn %p\n", isert_conn);

        mutex_lock(&isert_conn->mutex);
        if (isert_conn->state != ISER_CONN_FULL_FEATURE)
                isert_conn->state = ISER_CONN_UP;
        mutex_unlock(&isert_conn->mutex);
}

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

        isert_info("conn %p final kref %s/%d\n", isert_conn, current->comm,
                   current->pid);

        isert_connect_release(isert_conn);
}

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

/**
 * isert_conn_terminate() - Initiate connection termination
 * @isert_conn: isert connection struct
 *
 * Notes:
 * In case the connection state is FULL_FEATURE, move state
 * to TEMINATING and start teardown sequence (rdma_disconnect).
 * In case the connection state is UP, complete flush as well.
 *
 * This routine must be called with mutex held. Thus it is
 * safe to call multiple times.
 */
static void
isert_conn_terminate(struct isert_conn *isert_conn)
{
        int err;

        switch (isert_conn->state) {
        case ISER_CONN_TERMINATING:
                break;
        case ISER_CONN_UP:
        case ISER_CONN_FULL_FEATURE: /* FALLTHRU */
                isert_info("Terminating conn %p state %d\n",
                           isert_conn, isert_conn->state);
                isert_conn->state = ISER_CONN_TERMINATING;
                err = rdma_disconnect(isert_conn->cm_id);
                if (err)
                        isert_warn("Failed rdma_disconnect isert_conn %p\n",
                                   isert_conn);
                break;
        default:
                isert_warn("conn %p teminating in state %d\n",
                           isert_conn, isert_conn->state);
        }
}

static int
isert_np_cma_handler(struct isert_np *isert_np,
                     enum rdma_cm_event_type event)
{
        isert_dbg("%s (%d): isert np %p\n",
                  rdma_event_msg(event), event, isert_np);

        switch (event) {
        case RDMA_CM_EVENT_DEVICE_REMOVAL:
                isert_np->np_cm_id = NULL;
                break;
        case RDMA_CM_EVENT_ADDR_CHANGE:
                isert_np->np_cm_id = isert_setup_id(isert_np);
                if (IS_ERR(isert_np->np_cm_id)) {
                        isert_err("isert np %p setup id failed: %ld\n",
                                  isert_np, PTR_ERR(isert_np->np_cm_id));
                        isert_np->np_cm_id = NULL;
                }
                break;
        default:
                isert_err("isert np %p Unexpected event %d\n",
                          isert_np, event);
        }

        return -1;
}

static int
isert_disconnected_handler(struct rdma_cm_id *cma_id,
                           enum rdma_cm_event_type event)
{
        struct isert_np *isert_np = cma_id->context;
        struct isert_conn *isert_conn;
        bool terminating = false;

        if (isert_np->np_cm_id == cma_id)
                return isert_np_cma_handler(cma_id->context, event);

        isert_conn = cma_id->qp->qp_context;

        mutex_lock(&isert_conn->mutex);
        terminating = (isert_conn->state == ISER_CONN_TERMINATING);
        isert_conn_terminate(isert_conn);
        mutex_unlock(&isert_conn->mutex);

        isert_info("conn %p completing wait\n", isert_conn);
        complete(&isert_conn->wait);

        if (terminating)
                goto out;

        mutex_lock(&isert_np->np_accept_mutex);
        if (!list_empty(&isert_conn->accept_node)) {
                list_del_init(&isert_conn->accept_node);
                isert_put_conn(isert_conn);
                queue_work(isert_release_wq, &isert_conn->release_work);
        }
        mutex_unlock(&isert_np->np_accept_mutex);

out:
        return 0;
}

static int
isert_connect_error(struct rdma_cm_id *cma_id)
{
        struct isert_conn *isert_conn = cma_id->qp->qp_context;

        isert_conn->cm_id = NULL;
        isert_put_conn(isert_conn);

        return -1;
}

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

        isert_info("%s (%d): status %d id %p np %p\n",
                   rdma_event_msg(event->event), event->event,
                   event->status, cma_id, cma_id->context);

        switch (event->event) {
        case RDMA_CM_EVENT_CONNECT_REQUEST:
                ret = isert_connect_request(cma_id, event);
                if (ret)
                        isert_err("failed handle connect request %d\n", ret);
                break;
        case RDMA_CM_EVENT_ESTABLISHED:
                isert_connected_handler(cma_id);

                break;
        case RDMA_CM_EVENT_ADDR_CHANGE:    /* FALLTHRU */
        case RDMA_CM_EVENT_DISCONNECTED:   /* FALLTHRU */
        case RDMA_CM_EVENT_DEVICE_REMOVAL: /* FALLTHRU */
        case RDMA_CM_EVENT_TIMEWAIT_EXIT:  /* FALLTHRU */
                ret = isert_disconnected_handler(cma_id, event->event);
                break;
        case RDMA_CM_EVENT_REJECTED:       /* FALLTHRU */
        case RDMA_CM_EVENT_UNREACHABLE:    /* FALLTHRU */
        case RDMA_CM_EVENT_CONNECT_ERROR:
                ret = isert_connect_error(cma_id);
                break;
        default:
                isert_err("Unhandled RDMA CMA event: %d\n", event->event);
                break;
        }

        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->rx_desc_head;
        struct iser_rx_desc *rx_desc;

        for (rx_wr = isert_conn->rx_wr, i = 0; i < count; i++, rx_wr++) {
                rx_desc         = &isert_conn->rx_descs[rx_head];
                rx_wr->wr_id    = (uintptr_t)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->qp, isert_conn->rx_wr,
                                &rx_wr_failed);
        if (ret) {
                isert_err("ib_post_recv() failed with ret: %d\n", ret);
                isert_conn->post_recv_buf_count -= count;
        } else {
                isert_dbg("Posted %d RX buffers\n", count);
                isert_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->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   = (uintptr_t)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;

        ret = ib_post_send(isert_conn->qp, &send_wr, &send_wr_failed);
        if (ret)
                isert_err("ib_post_send() failed, ret: %d\n", ret);

        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 isert_device *device = isert_conn->device;
        struct ib_device *ib_dev = device->ib_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 != device->mr->lkey) {
                tx_desc->tx_sg[0].lkey = device->mr->lkey;
                isert_dbg("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 isert_device *device = isert_conn->device;
        struct ib_device *ib_dev = device->ib_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)) {
                isert_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 = device->mr->lkey;

        isert_dbg("Setup tx_sg[0].addr: 0x%llx length: %u lkey: 0x%x\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_conn *isert_conn, struct isert_cmd *isert_cmd,
                   struct ib_send_wr *send_wr)
{
        struct iser_tx_desc *tx_desc = &isert_cmd->tx_desc;

        isert_cmd->rdma_wr.iser_ib_op = ISER_IB_SEND;
        send_wr->wr_id = (uintptr_t)&isert_cmd->tx_desc;
        send_wr->opcode = IB_WR_SEND;
        send_wr->sg_list = &tx_desc->tx_sg[0];
        send_wr->num_sge = isert_cmd->tx_desc.num_sge;
        send_wr->send_flags = IB_SEND_SIGNALED;
}

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->device->mr->lkey;

        isert_dbg("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 = (uintptr_t)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->qp, &rx_wr, &rx_wr_fail);
        if (ret) {
                isert_err("ib_post_recv() failed: %d\n", ret);
                isert_conn->post_recv_buf_count--;
        }

        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 isert_device *device = isert_conn->device;
        struct ib_device *ib_dev = device->ib_device;
        struct iser_tx_desc *tx_desc = &isert_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->device->mr->lkey;
                tx_desc->num_sge = 2;
        }
        if (!login->login_failed) {
                if (login->login_complete) {
                        if (!conn->sess->sess_ops->SessionType &&
                            isert_conn->device->use_fastreg) {
                                ret = isert_conn_create_fastreg_pool(isert_conn);
                                if (ret) {
                                        isert_err("Conn: %p failed to create"
                                               " fastreg pool\n", isert_conn);
                                        return ret;
                                }
                        }

                        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;

                        /* Now we are in FULL_FEATURE phase */
                        mutex_lock(&isert_conn->mutex);
                        isert_conn->state = ISER_CONN_FULL_FEATURE;
                        mutex_unlock(&isert_conn->mutex);
                        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 isert_conn *isert_conn)
{
        struct iser_rx_desc *rx_desc = (void *)isert_conn->login_req_buf;
        int rx_buflen = isert_conn->login_req_len;
        struct iscsi_conn *conn = isert_conn->conn;
        struct iscsi_login *login = conn->conn_login;
        int size;

        isert_info("conn %p\n", isert_conn);

        WARN_ON_ONCE(!login);

        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);
        isert_dbg("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);

        if (login->first_request) {
                complete(&isert_conn->login_comp);
                return;
        }
        schedule_delayed_work(&conn->login_work, 0);
}

static struct iscsi_cmd
*isert_allocate_cmd(struct iscsi_conn *conn)
{
        struct isert_conn *isert_conn = conn->context;
        struct isert_cmd *isert_cmd;
        struct iscsi_cmd *cmd;

        cmd = iscsit_allocate_cmd(conn, TASK_INTERRUPTIBLE);
        if (!cmd) {
                isert_err("Unable to allocate iscsi_cmd + isert_cmd\n");
                return NULL;
        }
        isert_cmd = iscsit_priv_cmd(cmd);
        isert_cmd->conn = isert_conn;
        isert_cmd->iscsi_cmd = cmd;

        return cmd;
}

static int
isert_handle_scsi_cmd(struct isert_conn *isert_conn,
                      struct isert_cmd *isert_cmd, struct iscsi_cmd *cmd,
                      struct iser_rx_desc *rx_desc, unsigned char *buf)
{
        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));

        isert_dbg("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, buf, hdr->cmdsn);

        if (!rc && dump_payload == false && unsol_data)
                iscsit_set_unsoliticed_dataout(cmd);
        else if (dump_payload && imm_data)
                target_put_sess_cmd(&cmd->se_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) {
                isert_err("Received unexpected solicited data payload\n");
                dump_stack();
                return -1;
        }

        isert_dbg("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) {
                isert_err("unexpected non-page aligned data payload\n");
                dump_stack();
                return -1;
        }
        isert_dbg("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_handle_nop_out(struct isert_conn *isert_conn, struct isert_cmd *isert_cmd,
                     struct iscsi_cmd *cmd, struct iser_rx_desc *rx_desc,
                     unsigned char *buf)
{
        struct iscsi_conn *conn = isert_conn->conn;
        struct iscsi_nopout *hdr = (struct iscsi_nopout *)buf;
        int rc;

        rc = iscsit_setup_nop_out(conn, cmd, hdr);
        if (rc < 0)
                return rc;
        /*
         * FIXME: Add support for NOPOUT payload using unsolicited RDMA payload
         */

        return iscsit_process_nop_out(conn, cmd, hdr);
}

static int
isert_handle_text_cmd(struct isert_conn *isert_conn, struct isert_cmd *isert_cmd,
                      struct iscsi_cmd *cmd, struct iser_rx_desc *rx_desc,
                      struct iscsi_text *hdr)
{
        struct iscsi_conn *conn = isert_conn->conn;
        u32 payload_length = ntoh24(hdr->dlength);
        int rc;
        unsigned char *text_in = NULL;

        rc = iscsit_setup_text_cmd(conn, cmd, hdr);
        if (rc < 0)
                return rc;

        if (payload_length) {
                text_in = kzalloc(payload_length, GFP_KERNEL);
                if (!text_in) {
                        isert_err("Unable to allocate text_in of payload_length: %u\n",
                                  payload_length);
                        return -ENOMEM;
                }
        }
        cmd->text_in_ptr = text_in;

        memcpy(cmd->text_in_ptr, &rx_desc->data[0], payload_length);

        return iscsit_process_text_cmd(conn, cmd, hdr);
}

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);

        if (conn->sess->sess_ops->SessionType &&
           (!(opcode & ISCSI_OP_TEXT) || !(opcode & ISCSI_OP_LOGOUT))) {
                isert_err("Got illegal opcode: 0x%02x in SessionType=Discovery,"
                          " ignoring\n", opcode);
                return 0;
        }

        switch (opcode) {
        case ISCSI_OP_SCSI_CMD:
                cmd = isert_allocate_cmd(conn);
                if (!cmd)
                        break;

                isert_cmd = iscsit_priv_cmd(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, cmd,
                                        rx_desc, (unsigned char *)hdr);
                break;
        case ISCSI_OP_NOOP_OUT:
                cmd = isert_allocate_cmd(conn);
                if (!cmd)
                        break;

                isert_cmd = iscsit_priv_cmd(cmd);
                ret = isert_handle_nop_out(isert_conn, isert_cmd, cmd,
                                           rx_desc, (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 = isert_allocate_cmd(conn);
                if (!cmd)
                        break;

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

                ret = iscsit_handle_logout_cmd(conn, cmd, (unsigned char *)hdr);
                break;
        case ISCSI_OP_TEXT:
                if (be32_to_cpu(hdr->ttt) != 0xFFFFFFFF) {
                        cmd = iscsit_find_cmd_from_itt(conn, hdr->itt);
                        if (!cmd)
                                break;
                } else {
                        cmd = isert_allocate_cmd(conn);
                        if (!cmd)
                                break;
                }

                isert_cmd = iscsit_priv_cmd(cmd);
                ret = isert_handle_text_cmd(isert_conn, isert_cmd, cmd,
                                            rx_desc, (struct iscsi_text *)hdr);
                break;
        default:
                isert_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);
                        isert_dbg("ISER_RSV: read_stag: 0x%x read_va: 0x%llx\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);
                        isert_dbg("ISER_WSV: write_stag: 0x%x write_va: 0x%llx\n",
                                  write_stag, (unsigned long long)write_va);
                }

                isert_dbg("ISER ISCSI_CTRL PDU\n");
                break;
        case ISER_HELLO:
                isert_err("iSER Hello message\n");
                break;
        default:
                isert_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_rcv_completion(struct iser_rx_desc *desc,
                     struct isert_conn *isert_conn,
                     u32 xfer_len)
{
        struct ib_device *ib_dev = isert_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;
                isert_dbg("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;
                isert_dbg("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;
        isert_dbg("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_conn->login_req_len = xfer_len - ISER_HEADERS_LEN;
                if (isert_conn->conn) {
                        struct iscsi_login *login = isert_conn->conn->conn_login;

                        if (login && !login->first_request)
                                isert_rx_login_req(isert_conn);
                }
                mutex_lock(&isert_conn->mutex);
                complete(&isert_conn->login_req_comp);
                mutex_unlock(&isert_conn->mutex);
        } 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--;
        isert_dbg("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) {
                        isert_err("isert_post_recv() count: %d failed, %d\n",
                               count, err);
                }
        }
}

static int
isert_map_data_buf(struct isert_conn *isert_conn, struct isert_cmd *isert_cmd,
                   struct scatterlist *sg, u32 nents, u32 length, u32 offset,
                   enum iser_ib_op_code op, struct isert_data_buf *data)
{
        struct ib_device *ib_dev = isert_conn->cm_id->device;

        data->dma_dir = op == ISER_IB_RDMA_WRITE ?
                              DMA_TO_DEVICE : DMA_FROM_DEVICE;

        data->len = length - offset;
        data->offset = offset;
        data->sg_off = data->offset / PAGE_SIZE;

        data->sg = &sg[data->sg_off];
        data->nents = min_t(unsigned int, nents - data->sg_off,
                                          ISCSI_ISER_SG_TABLESIZE);
        data->len = min_t(unsigned int, data->len, ISCSI_ISER_SG_TABLESIZE *
                                        PAGE_SIZE);

        data->dma_nents = ib_dma_map_sg(ib_dev, data->sg, data->nents,
                                        data->dma_dir);
        if (unlikely(!data->dma_nents)) {
                isert_err("Cmd: unable to dma map SGs %p\n", sg);
                return -EINVAL;
        }

        isert_dbg("Mapped cmd: %p count: %u sg: %p sg_nents: %u rdma_len %d\n",
                  isert_cmd, data->dma_nents, data->sg, data->nents, data->len);

        return 0;
}

static void
isert_unmap_data_buf(struct isert_conn *isert_conn, struct isert_data_buf *data)
{
        struct ib_device *ib_dev = isert_conn->cm_id->device;

        ib_dma_unmap_sg(ib_dev, data->sg, data->nents, data->dma_dir);
        memset(data, 0, sizeof(*data));
}



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

        isert_dbg("Cmd %p\n", isert_cmd);

        if (wr->data.sg) {
                isert_dbg("Cmd %p unmap_sg op\n", isert_cmd);
                isert_unmap_data_buf(isert_conn, &wr->data);
        }

        if (wr->send_wr) {
                isert_dbg("Cmd %p free send_wr\n", isert_cmd);
                kfree(wr->send_wr);
                wr->send_wr = NULL;
        }

        if (wr->ib_sge) {
                isert_dbg("Cmd %p free ib_sge\n", isert_cmd);
                kfree(wr->ib_sge);
                wr->ib_sge = NULL;
        }
}

static void
isert_unreg_rdma(struct isert_cmd *isert_cmd, struct isert_conn *isert_conn)
{
        struct isert_rdma_wr *wr = &isert_cmd->rdma_wr;

        isert_dbg("Cmd %p\n", isert_cmd);

        if (wr->fr_desc) {
                isert_dbg("Cmd %p free fr_desc %p\n", isert_cmd, wr->fr_desc);
                if (wr->fr_desc->ind & ISERT_PROTECTED) {
                        isert_unmap_data_buf(isert_conn, &wr->prot);
                        wr->fr_desc->ind &= ~ISERT_PROTECTED;
                }
                spin_lock_bh(&isert_conn->pool_lock);
                list_add_tail(&wr->fr_desc->list, &isert_conn->fr_pool);
                spin_unlock_bh(&isert_conn->pool_lock);
                wr->fr_desc = NULL;
        }

        if (wr->data.sg) {
                isert_dbg("Cmd %p unmap_sg op\n", isert_cmd);
                isert_unmap_data_buf(isert_conn, &wr->data);
        }

        wr->ib_sge = NULL;
        wr->send_wr = NULL;
}

static void
isert_put_cmd(struct isert_cmd *isert_cmd, bool comp_err)
{
        struct iscsi_cmd *cmd = isert_cmd->iscsi_cmd;
        struct isert_conn *isert_conn = isert_cmd->conn;
        struct iscsi_conn *conn = isert_conn->conn;
        struct isert_device *device = isert_conn->device;
        struct iscsi_text_rsp *hdr;

        isert_dbg("Cmd %p\n", isert_cmd);

        switch (cmd->iscsi_opcode) {
        case ISCSI_OP_SCSI_CMD:
                spin_lock_bh(&conn->cmd_lock);
                if (!list_empty(&cmd->i_conn_node))
                        list_del_init(&cmd->i_conn_node);
                spin_unlock_bh(&conn->cmd_lock);

                if (cmd->data_direction == DMA_TO_DEVICE) {
                        iscsit_stop_dataout_timer(cmd);
                        /*
                         * Check for special case during comp_err where
                         * WRITE_PENDING has been handed off from core,
                         * but requires an extra target_put_sess_cmd()
                         * before transport_generic_free_cmd() below.
                         */
                        if (comp_err &&
                            cmd->se_cmd.t_state == TRANSPORT_WRITE_PENDING) {
                                struct se_cmd *se_cmd = &cmd->se_cmd;

                                target_put_sess_cmd(se_cmd);
                        }
                }

                device->unreg_rdma_mem(isert_cmd, isert_conn);
                transport_generic_free_cmd(&cmd->se_cmd, 0);
                break;
        case ISCSI_OP_SCSI_TMFUNC:
                spin_lock_bh(&conn->cmd_lock);
                if (!list_empty(&cmd->i_conn_node))
                        list_del_init(&cmd->i_conn_node);
                spin_unlock_bh(&conn->cmd_lock);

                transport_generic_free_cmd(&cmd->se_cmd, 0);
                break;
        case ISCSI_OP_REJECT:
        case ISCSI_OP_NOOP_OUT:
        case ISCSI_OP_TEXT:
                hdr = (struct iscsi_text_rsp *)&isert_cmd->tx_desc.iscsi_header;
                /* If the continue bit is on, keep the command alive */
                if (hdr->flags & ISCSI_FLAG_TEXT_CONTINUE)
                        break;

                spin_lock_bh(&conn->cmd_lock);
                if (!list_empty(&cmd->i_conn_node))
                        list_del_init(&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) {
                        isert_dbg("Calling transport_generic_free_cmd for 0x%02x\n",
                                 cmd->iscsi_opcode);
                        transport_generic_free_cmd(&cmd->se_cmd, 0);
                        break;
                }
                /*
                 * Fall-through
                 */
        default:
                iscsit_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) {
                isert_dbg("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, bool comp_err)
{
        if (isert_cmd->pdu_buf_dma != 0) {
                isert_dbg("unmap single for isert_cmd->pdu_buf_dma\n");
                ib_dma_unmap_single(ib_dev, isert_cmd->pdu_buf_dma,
                                    isert_cmd->pdu_buf_len, DMA_TO_DEVICE);
                isert_cmd->pdu_buf_dma = 0;
        }

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

static int
isert_check_pi_status(struct se_cmd *se_cmd, struct ib_mr *sig_mr)
{
        struct ib_mr_status mr_status;
        int ret;

        ret = ib_check_mr_status(sig_mr, IB_MR_CHECK_SIG_STATUS, &mr_status);
        if (ret) {
                isert_err("ib_check_mr_status failed, ret %d\n", ret);
                goto fail_mr_status;
        }

        if (mr_status.fail_status & IB_MR_CHECK_SIG_STATUS) {
                u64 sec_offset_err;
                u32 block_size = se_cmd->se_dev->dev_attrib.block_size + 8;

                switch (mr_status.sig_err.err_type) {
                case IB_SIG_BAD_GUARD:
                        se_cmd->pi_err = TCM_LOGICAL_BLOCK_GUARD_CHECK_FAILED;
                        break;
                case IB_SIG_BAD_REFTAG:
                        se_cmd->pi_err = TCM_LOGICAL_BLOCK_REF_TAG_CHECK_FAILED;
                        break;
                case IB_SIG_BAD_APPTAG:
                        se_cmd->pi_err = TCM_LOGICAL_BLOCK_APP_TAG_CHECK_FAILED;
                        break;
                }
                sec_offset_err = mr_status.sig_err.sig_err_offset;
                do_div(sec_offset_err, block_size);
                se_cmd->bad_sector = sec_offset_err + se_cmd->t_task_lba;

                isert_err("PI error found type %d at sector 0x%llx "
                          "expected 0x%x vs actual 0x%x\n",
                          mr_status.sig_err.err_type,
                          (unsigned long long)se_cmd->bad_sector,
                          mr_status.sig_err.expected,
                          mr_status.sig_err.actual);
                ret = 1;
        }

fail_mr_status:
        return ret;
}

static void
isert_completion_rdma_write(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 isert_conn *isert_conn = isert_cmd->conn;
        struct isert_device *device = isert_conn->device;
        int ret = 0;

        if (wr->fr_desc && wr->fr_desc->ind & ISERT_PROTECTED) {
                ret = isert_check_pi_status(se_cmd,
                                            wr->fr_desc->pi_ctx->sig_mr);
                wr->fr_desc->ind &= ~ISERT_PROTECTED;
        }

        device->unreg_rdma_mem(isert_cmd, isert_conn);
        wr->send_wr_num = 0;
        if (ret)
                transport_send_check_condition_and_sense(se_cmd,
                                                         se_cmd->pi_err, 0);
        else
                isert_put_response(isert_conn->conn, 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 isert_conn *isert_conn = isert_cmd->conn;
        struct isert_device *device = isert_conn->device;
        int ret = 0;

        if (wr->fr_desc && wr->fr_desc->ind & ISERT_PROTECTED) {
                ret = isert_check_pi_status(se_cmd,
                                            wr->fr_desc->pi_ctx->sig_mr);
                wr->fr_desc->ind &= ~ISERT_PROTECTED;
        }

        iscsit_stop_dataout_timer(cmd);
        device->unreg_rdma_mem(isert_cmd, isert_conn);
        cmd->write_data_done = wr->data.len;
        wr->send_wr_num = 0;

        isert_dbg("Cmd: %p RDMA_READ comp calling execute_cmd\n", isert_cmd);
        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);

        if (ret) {
                target_put_sess_cmd(se_cmd);
                transport_send_check_condition_and_sense(se_cmd,
                                                         se_cmd->pi_err, 0);
        } else {
                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->cm_id->device;
        struct iscsi_cmd *cmd = isert_cmd->iscsi_cmd;

        isert_dbg("Cmd %p i_state %d\n", isert_cmd, cmd->i_state);

        switch (cmd->i_state) {
        case ISTATE_SEND_TASKMGTRSP:
                iscsit_tmr_post_handler(cmd, cmd->conn);
        case ISTATE_SEND_REJECT:   /* FALLTHRU */
        case ISTATE_SEND_TEXTRSP:  /* FALLTHRU */
                cmd->i_state = ISTATE_SENT_STATUS;
                isert_completion_put(&isert_cmd->tx_desc, isert_cmd,
                                     ib_dev, false);
                break;
        case ISTATE_SEND_LOGOUTRSP:
                iscsit_logout_post_handler(cmd, cmd->conn);
                break;
        default:
                isert_err("Unknown 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 ||
            cmd->i_state == ISTATE_SEND_REJECT ||
            cmd->i_state == ISTATE_SEND_TEXTRSP) {
                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;
        }

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

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

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

        isert_dbg("Cmd %p iser_ib_op %d\n", isert_cmd, wr->iser_ib_op);

        switch (wr->iser_ib_op) {
        case ISER_IB_SEND:
                isert_response_completion(tx_desc, isert_cmd,
                                          isert_conn, ib_dev);
                break;
        case ISER_IB_RDMA_WRITE:
                isert_completion_rdma_write(tx_desc, isert_cmd);
                break;
        case ISER_IB_RDMA_READ:
                isert_completion_rdma_read(tx_desc, isert_cmd);
                break;
        default:
                isert_err("Unknown wr->iser_ib_op: 0x%x\n", wr->iser_ib_op);
                dump_stack();
                break;
        }
}

/**
 * is_isert_tx_desc() - Indicate if the completion wr_id
 *     is a TX descriptor or not.
 * @isert_conn: iser connection
 * @wr_id: completion WR identifier
 *
 * Since we cannot rely on wc opcode in FLUSH errors
 * we must work around it by checking if the wr_id address
 * falls in the iser connection rx_descs buffer. If so
 * it is an RX descriptor, otherwize it is a TX.
 */
static inline bool
is_isert_tx_desc(struct isert_conn *isert_conn, void *wr_id)
{
        void *start = isert_conn->rx_descs;
        int len = ISERT_QP_MAX_RECV_DTOS * sizeof(*isert_conn->rx_descs);

        if (wr_id >= start && wr_id < start + len)
                return false;

        return true;
}

static void
isert_cq_comp_err(struct isert_conn *isert_conn, struct ib_wc *wc)
{
        if (wc->wr_id == ISER_BEACON_WRID) {
                isert_info("conn %p completing wait_comp_err\n",
                           isert_conn);
                complete(&isert_conn->wait_comp_err);
        } else if (is_isert_tx_desc(isert_conn, (void *)(uintptr_t)wc->wr_id)) {
                struct ib_device *ib_dev = isert_conn->cm_id->device;
                struct isert_cmd *isert_cmd;
                struct iser_tx_desc *desc;

                desc = (struct iser_tx_desc *)(uintptr_t)wc->wr_id;
                isert_cmd = desc->isert_cmd;
                if (!isert_cmd)
                        isert_unmap_tx_desc(desc, ib_dev);
                else
                        isert_completion_put(desc, isert_cmd, ib_dev, true);
        } else {
                isert_conn->post_recv_buf_count--;
                if (!isert_conn->post_recv_buf_count)
                        iscsit_cause_connection_reinstatement(isert_conn->conn, 0);
        }
}

static void
isert_handle_wc(struct ib_wc *wc)
{
        struct isert_conn *isert_conn;
        struct iser_tx_desc *tx_desc;
        struct iser_rx_desc *rx_desc;

        isert_conn = wc->qp->qp_context;
        if (likely(wc->status == IB_WC_SUCCESS)) {
                if (wc->opcode == IB_WC_RECV) {
                        rx_desc = (struct iser_rx_desc *)(uintptr_t)wc->wr_id;
                        isert_rcv_completion(rx_desc, isert_conn, wc->byte_len);
                } else {
                        tx_desc = (struct iser_tx_desc *)(uintptr_t)wc->wr_id;
                        isert_snd_completion(tx_desc, isert_conn);
                }
        } else {
                if (wc->status != IB_WC_WR_FLUSH_ERR)
                        isert_err("%s (%d): wr id %llx vend_err %x\n",
                                  ib_wc_status_msg(wc->status), wc->status,
                                  wc->wr_id, wc->vendor_err);
                else
                        isert_dbg("%s (%d): wr id %llx\n",
                                  ib_wc_status_msg(wc->status), wc->status,
                                  wc->wr_id);

                if (wc->wr_id != ISER_FASTREG_LI_WRID)
                        isert_cq_comp_err(isert_conn, wc);
        }
}

static void
isert_cq_work(struct work_struct *work)
{
        enum { isert_poll_budget = 65536 };
        struct isert_comp *comp = container_of(work, struct isert_comp,
                                               work);
        struct ib_wc *const wcs = comp->wcs;
        int i, n, completed = 0;

        while ((n = ib_poll_cq(comp->cq, ARRAY_SIZE(comp->wcs), wcs)) > 0) {
                for (i = 0; i < n; i++)
                        isert_handle_wc(&wcs[i]);

                completed += n;
                if (completed >= isert_poll_budget)
                        break;
        }

        ib_req_notify_cq(comp->cq, IB_CQ_NEXT_COMP);
}

static void
isert_cq_callback(struct ib_cq *cq, void *context)
{
        struct isert_comp *comp = context;

        queue_work(isert_comp_wq, &comp->work);
}

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

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

static int
isert_put_response(struct iscsi_conn *conn, struct iscsi_cmd *cmd)
{
        struct isert_cmd *isert_cmd = iscsit_priv_cmd(cmd);
        struct isert_conn *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 isert_device *device = isert_conn->device;
                struct ib_device *ib_dev = device->ib_device;
                struct ib_sge *tx_dsg = &isert_cmd->tx_desc.tx_sg[1];
                u32 padding, pdu_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);
                pdu_len = cmd->se_cmd.scsi_sense_length + padding;

                isert_cmd->pdu_buf_dma = ib_dma_map_single(ib_dev,
                                (void *)cmd->sense_buffer, pdu_len,
                                DMA_TO_DEVICE);

                isert_cmd->pdu_buf_len = pdu_len;
                tx_dsg->addr    = isert_cmd->pdu_buf_dma;
                tx_dsg->length  = pdu_len;
                tx_dsg->lkey    = device->mr->lkey;
                isert_cmd->tx_desc.num_sge = 2;
        }

        isert_init_send_wr(isert_conn, isert_cmd, send_wr);

        isert_dbg("Posting SCSI Response\n");

        return isert_post_response(isert_conn, isert_cmd);
}

static void
isert_aborted_task(struct iscsi_conn *conn, struct iscsi_cmd *cmd)
{
        struct isert_cmd *isert_cmd = iscsit_priv_cmd(cmd);
        struct isert_conn *isert_conn = conn->context;
        struct isert_device *device = isert_conn->device;

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

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

        device->unreg_rdma_mem(isert_cmd, isert_conn);
}

static enum target_prot_op
isert_get_sup_prot_ops(struct iscsi_conn *conn)
{
        struct isert_conn *isert_conn = conn->context;
        struct isert_device *device = isert_conn->device;

        if (conn->tpg->tpg_attrib.t10_pi) {
                if (device->pi_capable) {
                        isert_info("conn %p PI offload enabled\n", isert_conn);
                        isert_conn->pi_support = true;
                        return TARGET_PROT_ALL;
                }
        }

        isert_info("conn %p PI offload disabled\n", isert_conn);
        isert_conn->pi_support = false;

        return TARGET_PROT_NORMAL;
}

static int
isert_put_nopin(struct iscsi_cmd *cmd, struct iscsi_conn *conn,
                bool nopout_response)
{
        struct isert_cmd *isert_cmd = iscsit_priv_cmd(cmd);
        struct isert_conn *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_conn, isert_cmd, send_wr);

        isert_dbg("conn %p Posting NOPIN Response\n", isert_conn);

        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 = iscsit_priv_cmd(cmd);
        struct isert_conn *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_conn, isert_cmd, send_wr);

        isert_dbg("conn %p Posting Logout Response\n", isert_conn);

        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 = iscsit_priv_cmd(cmd);
        struct isert_conn *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_conn, isert_cmd, send_wr);

        isert_dbg("conn %p Posting Task Management Response\n", isert_conn);

        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 = iscsit_priv_cmd(cmd);
        struct isert_conn *isert_conn = conn->context;
        struct ib_send_wr *send_wr = &isert_cmd->tx_desc.send_wr;
        struct isert_device *device = isert_conn->device;
        struct ib_device *ib_dev = device->ib_device;
        struct ib_sge *tx_dsg = &isert_cmd->tx_desc.tx_sg[1];
        struct iscsi_reject *hdr =
                (struct iscsi_reject *)&isert_cmd->tx_desc.iscsi_header;

        isert_create_send_desc(isert_conn, isert_cmd, &isert_cmd->tx_desc);
        iscsit_build_reject(cmd, conn, hdr);
        isert_init_tx_hdrs(isert_conn, &isert_cmd->tx_desc);

        hton24(hdr->dlength, ISCSI_HDR_LEN);
        isert_cmd->pdu_buf_dma = ib_dma_map_single(ib_dev,
                        (void *)cmd->buf_ptr, ISCSI_HDR_LEN,
                        DMA_TO_DEVICE);
        isert_cmd->pdu_buf_len = ISCSI_HDR_LEN;
        tx_dsg->addr    = isert_cmd->pdu_buf_dma;
        tx_dsg->length  = ISCSI_HDR_LEN;
        tx_dsg->lkey    = device->mr->lkey;
        isert_cmd->tx_desc.num_sge = 2;

        isert_init_send_wr(isert_conn, isert_cmd, send_wr);

        isert_dbg("conn %p Posting Reject\n", isert_conn);

        return isert_post_response(isert_conn, isert_cmd);
}

static int
isert_put_text_rsp(struct iscsi_cmd *cmd, struct iscsi_conn *conn)
{
        struct isert_cmd *isert_cmd = iscsit_priv_cmd(cmd);
        struct isert_conn *isert_conn = conn->context;
        struct ib_send_wr *send_wr = &isert_cmd->tx_desc.send_wr;
        struct iscsi_text_rsp *hdr =
                (struct iscsi_text_rsp *)&isert_cmd->tx_desc.iscsi_header;
        u32 txt_rsp_len;
        int rc;

        isert_create_send_desc(isert_conn, isert_cmd, &isert_cmd->tx_desc);
        rc = iscsit_build_text_rsp(cmd, conn, hdr, ISCSI_INFINIBAND);
        if (rc < 0)
                return rc;

        txt_rsp_len = rc;
        isert_init_tx_hdrs(isert_conn, &isert_cmd->tx_desc);

        if (txt_rsp_len) {
                struct isert_device *device = isert_conn->device;
                struct ib_device *ib_dev = device->ib_device;
                struct ib_sge *tx_dsg = &isert_cmd->tx_desc.tx_sg[1];
                void *txt_rsp_buf = cmd->buf_ptr;

                isert_cmd->pdu_buf_dma = ib_dma_map_single(ib_dev,
                                txt_rsp_buf, txt_rsp_len, DMA_TO_DEVICE);

                isert_cmd->pdu_buf_len = txt_rsp_len;
                tx_dsg->addr    = isert_cmd->pdu_buf_dma;
                tx_dsg->length  = txt_rsp_len;
                tx_dsg->lkey    = device->mr->lkey;
                isert_cmd->tx_desc.num_sge = 2;
        }
        isert_init_send_wr(isert_conn, isert_cmd, send_wr);

        isert_dbg("conn %p Text Response\n", isert_conn);

        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 isert_device *device = isert_conn->device;
        struct ib_device *ib_dev = device->ib_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->wr_id = (uintptr_t)&isert_cmd->tx_desc;
        /*
         * Perform mapping of TCM scatterlist memory ib_sge dma_addr.
         */
        for_each_sg(sg_start, tmp_sg, sg_nents, i) {
                isert_dbg("RDMA from SGL dma_addr: 0x%llx 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 = device->mr->lkey;

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

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

        return send_wr->num_sge;
}

static int
isert_map_rdma(struct iscsi_conn *conn, struct iscsi_cmd *cmd,
               struct isert_rdma_wr *wr)
{
        struct se_cmd *se_cmd = &cmd->se_cmd;
        struct isert_cmd *isert_cmd = iscsit_priv_cmd(cmd);
        struct isert_conn *isert_conn = conn->context;
        struct isert_data_buf *data = &wr->data;
        struct ib_send_wr *send_wr;
        struct ib_sge *ib_sge;
        u32 offset, data_len, data_left, rdma_write_max, va_offset = 0;
        int ret = 0, i, ib_sge_cnt;

        isert_cmd->tx_desc.isert_cmd = isert_cmd;

        offset = wr->iser_ib_op == ISER_IB_RDMA_READ ? cmd->write_data_done : 0;
        ret = isert_map_data_buf(isert_conn, isert_cmd, se_cmd->t_data_sg,
                                 se_cmd->t_data_nents, se_cmd->data_length,
                                 offset, wr->iser_ib_op, &wr->data);
        if (ret)
                return ret;

        data_left = data->len;
        offset = data->offset;

        ib_sge = kzalloc(sizeof(struct ib_sge) * data->nents, GFP_KERNEL);
        if (!ib_sge) {
                isert_warn("Unable to allocate ib_sge\n");
                ret = -ENOMEM;
                goto unmap_cmd;
        }
        wr->ib_sge = ib_sge;

        wr->send_wr_num = DIV_ROUND_UP(data->nents, isert_conn->max_sge);
        wr->send_wr = kzalloc(sizeof(struct ib_send_wr) * wr->send_wr_num,
                                GFP_KERNEL);
        if (!wr->send_wr) {
                isert_dbg("Unable to allocate wr->send_wr\n");
                ret = -ENOMEM;
                goto unmap_cmd;
        }

        wr->isert_cmd = isert_cmd;
        rdma_write_max = isert_conn->max_sge * PAGE_SIZE;

        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->send_flags = 0;
                if (wr->iser_ib_op == ISER_IB_RDMA_WRITE) {
                        send_wr->opcode = IB_WR_RDMA_WRITE;
                        send_wr->wr.rdma.remote_addr = isert_cmd->read_va + offset;
                        send_wr->wr.rdma.rkey = isert_cmd->read_stag;
                        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];
                } else {
                        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;
                        if (i + 1 == wr->send_wr_num)
                                send_wr->send_flags = IB_SEND_SIGNALED;
                        else
                                send_wr->next = &wr->send_wr[i + 1];
                }

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

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

        return 0;
unmap_cmd:
        isert_unmap_data_buf(isert_conn, data);

        return ret;
}

static int
isert_map_fr_pagelist(struct ib_device *ib_dev,
                      struct scatterlist *sg_start, int sg_nents, u64 *fr_pl)
{
        u64 start_addr, end_addr, page, chunk_start = 0;
        struct scatterlist *tmp_sg;
        int i = 0, new_chunk, last_ent, n_pages;

        n_pages = 0;
        new_chunk = 1;
        last_ent = sg_nents - 1;
        for_each_sg(sg_start, tmp_sg, sg_nents, i) {
                start_addr = ib_sg_dma_address(ib_dev, tmp_sg);
                if (new_chunk)
                        chunk_start = start_addr;
                end_addr = start_addr + ib_sg_dma_len(ib_dev, tmp_sg);

                isert_dbg("SGL[%d] dma_addr: 0x%llx len: %u\n",
                          i, (unsigned long long)tmp_sg->dma_address,
                          tmp_sg->length);

                if ((end_addr & ~PAGE_MASK) && i < last_ent) {
                        new_chunk = 0;
                        continue;
                }
                new_chunk = 1;

                page = chunk_start & PAGE_MASK;
                do {
                        fr_pl[n_pages++] = page;
                        isert_dbg("Mapped page_list[%d] page_addr: 0x%llx\n",
                                  n_pages - 1, page);
                        page += PAGE_SIZE;
                } while (page < end_addr);
        }

        return n_pages;
}

static inline void
isert_inv_rkey(struct ib_send_wr *inv_wr, struct ib_mr *mr)
{
        u32 rkey;

        memset(inv_wr, 0, sizeof(*inv_wr));
        inv_wr->wr_id = ISER_FASTREG_LI_WRID;
        inv_wr->opcode = IB_WR_LOCAL_INV;
        inv_wr->ex.invalidate_rkey = mr->rkey;

        /* Bump the key */
        rkey = ib_inc_rkey(mr->rkey);
        ib_update_fast_reg_key(mr, rkey);
}

static int
isert_fast_reg_mr(struct isert_conn *isert_conn,
                  struct fast_reg_descriptor *fr_desc,
                  struct isert_data_buf *mem,
                  enum isert_indicator ind,
                  struct ib_sge *sge)
{
        struct isert_device *device = isert_conn->device;
        struct ib_device *ib_dev = device->ib_device;
        struct ib_mr *mr;
        struct ib_fast_reg_page_list *frpl;
        struct ib_send_wr fr_wr, inv_wr;
        struct ib_send_wr *bad_wr, *wr = NULL;
        int ret, pagelist_len;
        u32 page_off;

        if (mem->dma_nents == 1) {
                sge->lkey = device->mr->lkey;
                sge->addr = ib_sg_dma_address(ib_dev, &mem->sg[0]);
                sge->length = ib_sg_dma_len(ib_dev, &mem->sg[0]);
                isert_dbg("sge: addr: 0x%llx  length: %u lkey: %x\n",
                         sge->addr, sge->length, sge->lkey);
                return 0;
        }

        if (ind == ISERT_DATA_KEY_VALID) {
                /* Registering data buffer */
                mr = fr_desc->data_mr;
                frpl = fr_desc->data_frpl;
        } else {
                /* Registering protection buffer */
                mr = fr_desc->pi_ctx->prot_mr;
                frpl = fr_desc->pi_ctx->prot_frpl;
        }

        page_off = mem->offset % PAGE_SIZE;

        isert_dbg("Use fr_desc %p sg_nents %d offset %u\n",
                  fr_desc, mem->nents, mem->offset);

        pagelist_len = isert_map_fr_pagelist(ib_dev, mem->sg, mem->nents,
                                             &frpl->page_list[0]);

        if (!(fr_desc->ind & ind)) {
                isert_inv_rkey(&inv_wr, mr);
                wr = &inv_wr;
        }

        /* Prepare FASTREG WR */
        memset(&fr_wr, 0, sizeof(fr_wr));
        fr_wr.wr_id = ISER_FASTREG_LI_WRID;
        fr_wr.opcode = IB_WR_FAST_REG_MR;
        fr_wr.wr.fast_reg.iova_start = frpl->page_list[0] + page_off;
        fr_wr.wr.fast_reg.page_list = frpl;
        fr_wr.wr.fast_reg.page_list_len = pagelist_len;
        fr_wr.wr.fast_reg.page_shift = PAGE_SHIFT;
        fr_wr.wr.fast_reg.length = mem->len;
        fr_wr.wr.fast_reg.rkey = mr->rkey;
        fr_wr.wr.fast_reg.access_flags = IB_ACCESS_LOCAL_WRITE;

        if (!wr)
                wr = &fr_wr;
        else
                wr->next = &fr_wr;

        ret = ib_post_send(isert_conn->qp, wr, &bad_wr);
        if (ret) {
                isert_err("fast registration failed, ret:%d\n", ret);
                return ret;
        }
        fr_desc->ind &= ~ind;

        sge->lkey = mr->lkey;
        sge->addr = frpl->page_list[0] + page_off;
        sge->length = mem->len;

        isert_dbg("sge: addr: 0x%llx  length: %u lkey: %x\n",
                  sge->addr, sge->length, sge->lkey);

        return ret;
}

static inline void
isert_set_dif_domain(struct se_cmd *se_cmd, struct ib_sig_attrs *sig_attrs,
                     struct ib_sig_domain *domain)
{
        domain->sig_type = IB_SIG_TYPE_T10_DIF;
        domain->sig.dif.bg_type = IB_T10DIF_CRC;
        domain->sig.dif.pi_interval = se_cmd->se_dev->dev_attrib.block_size;
        domain->sig.dif.ref_tag = se_cmd->reftag_seed;
        /*
         * At the moment we hard code those, but if in the future
         * the target core would like to use it, we will take it
         * from se_cmd.
         */
        domain->sig.dif.apptag_check_mask = 0xffff;
        domain->sig.dif.app_escape = true;
        domain->sig.dif.ref_escape = true;
        if (se_cmd->prot_type == TARGET_DIF_TYPE1_PROT ||
            se_cmd->prot_type == TARGET_DIF_TYPE2_PROT)
                domain->sig.dif.ref_remap = true;
};

static int
isert_set_sig_attrs(struct se_cmd *se_cmd, struct ib_sig_attrs *sig_attrs)
{
        switch (se_cmd->prot_op) {
        case TARGET_PROT_DIN_INSERT:
        case TARGET_PROT_DOUT_STRIP:
                sig_attrs->mem.sig_type = IB_SIG_TYPE_NONE;
                isert_set_dif_domain(se_cmd, sig_attrs, &sig_attrs->wire);
                break;
        case TARGET_PROT_DOUT_INSERT:
        case TARGET_PROT_DIN_STRIP:
                sig_attrs->wire.sig_type = IB_SIG_TYPE_NONE;
                isert_set_dif_domain(se_cmd, sig_attrs, &sig_attrs->mem);
                break;
        case TARGET_PROT_DIN_PASS:
        case TARGET_PROT_DOUT_PASS:
                isert_set_dif_domain(se_cmd, sig_attrs, &sig_attrs->wire);
                isert_set_dif_domain(se_cmd, sig_attrs, &sig_attrs->mem);
                break;
        default:
                isert_err("Unsupported PI operation %d\n", se_cmd->prot_op);
                return -EINVAL;
        }

        return 0;
}

static inline u8
isert_set_prot_checks(u8 prot_checks)
{
        return (prot_checks & TARGET_DIF_CHECK_GUARD  ? 0xc0 : 0) |
               (prot_checks & TARGET_DIF_CHECK_REFTAG ? 0x30 : 0) |
               (prot_checks & TARGET_DIF_CHECK_REFTAG ? 0x0f : 0);
}

static int
isert_reg_sig_mr(struct isert_conn *isert_conn,
                 struct se_cmd *se_cmd,
                 struct isert_rdma_wr *rdma_wr,
                 struct fast_reg_descriptor *fr_desc)
{
        struct ib_send_wr sig_wr, inv_wr;
        struct ib_send_wr *bad_wr, *wr = NULL;
        struct pi_context *pi_ctx = fr_desc->pi_ctx;
        struct ib_sig_attrs sig_attrs;
        int ret;

        memset(&sig_attrs, 0, sizeof(sig_attrs));
        ret = isert_set_sig_attrs(se_cmd, &sig_attrs);
        if (ret)
                goto err;

        sig_attrs.check_mask = isert_set_prot_checks(se_cmd->prot_checks);

        if (!(fr_desc->ind & ISERT_SIG_KEY_VALID)) {
                isert_inv_rkey(&inv_wr, pi_ctx->sig_mr);
                wr = &inv_wr;
        }

        memset(&sig_wr, 0, sizeof(sig_wr));
        sig_wr.opcode = IB_WR_REG_SIG_MR;
        sig_wr.wr_id = ISER_FASTREG_LI_WRID;
        sig_wr.sg_list = &rdma_wr->ib_sg[DATA];
        sig_wr.num_sge = 1;
        sig_wr.wr.sig_handover.access_flags = IB_ACCESS_LOCAL_WRITE;
        sig_wr.wr.sig_handover.sig_attrs = &sig_attrs;
        sig_wr.wr.sig_handover.sig_mr = pi_ctx->sig_mr;
        if (se_cmd->t_prot_sg)
                sig_wr.wr.sig_handover.prot = &rdma_wr->ib_sg[PROT];

        if (!wr)
                wr = &sig_wr;
        else
                wr->next = &sig_wr;

        ret = ib_post_send(isert_conn->qp, wr, &bad_wr);
        if (ret) {
                isert_err("fast registration failed, ret:%d\n", ret);
                goto err;
        }
        fr_desc->ind &= ~ISERT_SIG_KEY_VALID;

        rdma_wr->ib_sg[SIG].lkey = pi_ctx->sig_mr->lkey;
        rdma_wr->ib_sg[SIG].addr = 0;
        rdma_wr->ib_sg[SIG].length = se_cmd->data_length;
        if (se_cmd->prot_op != TARGET_PROT_DIN_STRIP &&
            se_cmd->prot_op != TARGET_PROT_DOUT_INSERT)
                /*
                 * We have protection guards on the wire
                 * so we need to set a larget transfer
                 */
                rdma_wr->ib_sg[SIG].length += se_cmd->prot_length;

        isert_dbg("sig_sge: addr: 0x%llx  length: %u lkey: %x\n",
                  rdma_wr->ib_sg[SIG].addr, rdma_wr->ib_sg[SIG].length,
                  rdma_wr->ib_sg[SIG].lkey);
err:
        return ret;
}

static int
isert_handle_prot_cmd(struct isert_conn *isert_conn,
                      struct isert_cmd *isert_cmd,
                      struct isert_rdma_wr *wr)
{
        struct isert_device *device = isert_conn->device;
        struct se_cmd *se_cmd = &isert_cmd->iscsi_cmd->se_cmd;
        int ret;

        if (!wr->fr_desc->pi_ctx) {
                ret = isert_create_pi_ctx(wr->fr_desc,
                                          device->ib_device,
                                          device->pd);
                if (ret) {
                        isert_err("conn %p failed to allocate pi_ctx\n",
                                  isert_conn);
                        return ret;
                }
        }

        if (se_cmd->t_prot_sg) {
                ret = isert_map_data_buf(isert_conn, isert_cmd,
                                         se_cmd->t_prot_sg,
                                         se_cmd->t_prot_nents,
                                         se_cmd->prot_length,
                                         0, wr->iser_ib_op, &wr->prot);
                if (ret) {
                        isert_err("conn %p failed to map protection buffer\n",
                                  isert_conn);
                        return ret;
                }

                memset(&wr->ib_sg[PROT], 0, sizeof(wr->ib_sg[PROT]));
                ret = isert_fast_reg_mr(isert_conn, wr->fr_desc, &wr->prot,
                                        ISERT_PROT_KEY_VALID, &wr->ib_sg[PROT]);
                if (ret) {
                        isert_err("conn %p failed to fast reg mr\n",
                                  isert_conn);
                        goto unmap_prot_cmd;
                }
        }

        ret = isert_reg_sig_mr(isert_conn, se_cmd, wr, wr->fr_desc);
        if (ret) {
                isert_err("conn %p failed to fast reg mr\n",
                          isert_conn);
                goto unmap_prot_cmd;
        }
        wr->fr_desc->ind |= ISERT_PROTECTED;

        return 0;

unmap_prot_cmd:
        if (se_cmd->t_prot_sg)
                isert_unmap_data_buf(isert_conn, &wr->prot);

        return ret;
}

static int
isert_reg_rdma(struct iscsi_conn *conn, struct iscsi_cmd *cmd,
               struct isert_rdma_wr *wr)
{
        struct se_cmd *se_cmd = &cmd->se_cmd;
        struct isert_cmd *isert_cmd = iscsit_priv_cmd(cmd);
        struct isert_conn *isert_conn = conn->context;
        struct fast_reg_descriptor *fr_desc = NULL;
        struct ib_send_wr *send_wr;
        struct ib_sge *ib_sg;
        u32 offset;
        int ret = 0;
        unsigned long flags;

        isert_cmd->tx_desc.isert_cmd = isert_cmd;

        offset = wr->iser_ib_op == ISER_IB_RDMA_READ ? cmd->write_data_done : 0;
        ret = isert_map_data_buf(isert_conn, isert_cmd, se_cmd->t_data_sg,
                                 se_cmd->t_data_nents, se_cmd->data_length,
                                 offset, wr->iser_ib_op, &wr->data);
        if (ret)
                return ret;

        if (wr->data.dma_nents != 1 || isert_prot_cmd(isert_conn, se_cmd)) {
                spin_lock_irqsave(&isert_conn->pool_lock, flags);
                fr_desc = list_first_entry(&isert_conn->fr_pool,
                                           struct fast_reg_descriptor, list);
                list_del(&fr_desc->list);
                spin_unlock_irqrestore(&isert_conn->pool_lock, flags);
                wr->fr_desc = fr_desc;
        }

        ret = isert_fast_reg_mr(isert_conn, fr_desc, &wr->data,
                                ISERT_DATA_KEY_VALID, &wr->ib_sg[DATA]);
        if (ret)
                goto unmap_cmd;

        if (isert_prot_cmd(isert_conn, se_cmd)) {
                ret = isert_handle_prot_cmd(isert_conn, isert_cmd, wr);
                if (ret)
                        goto unmap_cmd;

                ib_sg = &wr->ib_sg[SIG];
        } else {
                ib_sg = &wr->ib_sg[DATA];
        }

        memcpy(&wr->s_ib_sge, ib_sg, sizeof(*ib_sg));
        wr->ib_sge = &wr->s_ib_sge;
        wr->send_wr_num = 1;
        memset(&wr->s_send_wr, 0, sizeof(*send_wr));
        wr->send_wr = &wr->s_send_wr;
        wr->isert_cmd = isert_cmd;

        send_wr = &isert_cmd->rdma_wr.s_send_wr;
        send_wr->sg_list = &wr->s_ib_sge;
        send_wr->num_sge = 1;
        send_wr->wr_id = (uintptr_t)&isert_cmd->tx_desc;
        if (wr->iser_ib_op == ISER_IB_RDMA_WRITE) {
                send_wr->opcode = IB_WR_RDMA_WRITE;
                send_wr->wr.rdma.remote_addr = isert_cmd->read_va;
                send_wr->wr.rdma.rkey = isert_cmd->read_stag;
                send_wr->send_flags = !isert_prot_cmd(isert_conn, se_cmd) ?
                                      0 : IB_SEND_SIGNALED;
        } else {
                send_wr->opcode = IB_WR_RDMA_READ;
                send_wr->wr.rdma.remote_addr = isert_cmd->write_va;
                send_wr->wr.rdma.rkey = isert_cmd->write_stag;
                send_wr->send_flags = IB_SEND_SIGNALED;
        }

        return 0;

unmap_cmd:
        if (fr_desc) {
                spin_lock_irqsave(&isert_conn->pool_lock, flags);
                list_add_tail(&fr_desc->list, &isert_conn->fr_pool);
                spin_unlock_irqrestore(&isert_conn->pool_lock, flags);
        }
        isert_unmap_data_buf(isert_conn, &wr->data);

        return ret;
}

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 = iscsit_priv_cmd(cmd);
        struct isert_rdma_wr *wr = &isert_cmd->rdma_wr;
        struct isert_conn *isert_conn = conn->context;
        struct isert_device *device = isert_conn->device;
        struct ib_send_wr *wr_failed;
        int rc;

        isert_dbg("Cmd: %p RDMA_WRITE data_length: %u\n",
                 isert_cmd, se_cmd->data_length);

        wr->iser_ib_op = ISER_IB_RDMA_WRITE;
        rc = device->reg_rdma_mem(conn, cmd, wr);
        if (rc) {
                isert_err("Cmd: %p failed to prepare RDMA res\n", isert_cmd);
                return rc;
        }

        if (!isert_prot_cmd(isert_conn, se_cmd)) {
                /*
                 * 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, true, (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_conn, isert_cmd,
                                   &isert_cmd->tx_desc.send_wr);
                isert_cmd->rdma_wr.s_send_wr.next = &isert_cmd->tx_desc.send_wr;
                wr->send_wr_num += 1;
        }

        rc = ib_post_send(isert_conn->qp, wr->send_wr, &wr_failed);
        if (rc)
                isert_warn("ib_post_send() failed for IB_WR_RDMA_WRITE\n");

        if (!isert_prot_cmd(isert_conn, se_cmd))
                isert_dbg("Cmd: %p posted RDMA_WRITE + Response for iSER Data "
                         "READ\n", isert_cmd);
        else
                isert_dbg("Cmd: %p posted RDMA_WRITE for iSER Data READ\n",
                         isert_cmd);

        return 1;
}

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 = iscsit_priv_cmd(cmd);
        struct isert_rdma_wr *wr = &isert_cmd->rdma_wr;
        struct isert_conn *isert_conn = conn->context;
        struct isert_device *device = isert_conn->device;
        struct ib_send_wr *wr_failed;
        int rc;

        isert_dbg("Cmd: %p RDMA_READ data_length: %u write_data_done: %u\n",
                 isert_cmd, se_cmd->data_length, cmd->write_data_done);
        wr->iser_ib_op = ISER_IB_RDMA_READ;
        rc = device->reg_rdma_mem(conn, cmd, wr);
        if (rc) {
                isert_err("Cmd: %p failed to prepare RDMA res\n", isert_cmd);
                return rc;
        }