// SPDX-License-Identifier: GPL-2.0-or-later
/*******************************************************************************
 * This file contains iSCSI extentions for RDMA (iSER) Verbs
 *
 * (c) Copyright 2013 Datera, Inc.
 *
 * Nicholas A. Bellinger <nab@linux-iscsi.org>
 *
 ****************************************************************************/

#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/ib_cm.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 "ib_isert.h"

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 int isert_sg_tablesize_set(const char *val,
                                  const struct kernel_param *kp);
static const struct kernel_param_ops sg_tablesize_ops = {
        .set = isert_sg_tablesize_set,
        .get = param_get_int,
};

static int isert_sg_tablesize = ISCSI_ISER_MIN_SG_TABLESIZE;
module_param_cb(sg_tablesize, &sg_tablesize_ops, &isert_sg_tablesize, 0644);
MODULE_PARM_DESC(sg_tablesize,
                 "Number of gather/scatter entries in a single scsi command, should >= 128 (default: 128, max: 4096)");

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 int
isert_put_response(struct iscsi_conn *conn, struct iscsi_cmd *cmd);
static int
isert_login_post_recv(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 void isert_recv_done(struct ib_cq *cq, struct ib_wc *wc);
static void isert_send_done(struct ib_cq *cq, struct ib_wc *wc);
static void isert_login_recv_done(struct ib_cq *cq, struct ib_wc *wc);
static void isert_login_send_done(struct ib_cq *cq, struct ib_wc *wc);

static int isert_sg_tablesize_set(const char *val, const struct kernel_param *kp)
{
        int n = 0, ret;

        ret = kstrtoint(val, 10, &n);
        if (ret != 0 || n < ISCSI_ISER_MIN_SG_TABLESIZE ||
            n > ISCSI_ISER_MAX_SG_TABLESIZE)
                return -EINVAL;

        return param_set_int(val, kp);
}

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 struct ib_qp *
isert_create_qp(struct isert_conn *isert_conn,
                struct rdma_cm_id *cma_id)
{
        u32 cq_size = ISERT_QP_MAX_REQ_DTOS + ISERT_QP_MAX_RECV_DTOS + 2;
        struct isert_device *device = isert_conn->device;
        struct ib_device *ib_dev = device->ib_device;
        struct ib_qp_init_attr attr;
        int ret, factor;

        isert_conn->cq = ib_cq_pool_get(ib_dev, cq_size, -1, IB_POLL_WORKQUEUE);
        if (IS_ERR(isert_conn->cq)) {
                isert_err("Unable to allocate cq\n");
                ret = PTR_ERR(isert_conn->cq);
                return ERR_PTR(ret);
        }
        isert_conn->cq_size = cq_size;

        memset(&attr, 0, sizeof(struct ib_qp_init_attr));
        attr.event_handler = isert_qp_event_callback;
        attr.qp_context = isert_conn;
        attr.send_cq = isert_conn->cq;
        attr.recv_cq = isert_conn->cq;
        attr.cap.max_send_wr = ISERT_QP_MAX_REQ_DTOS + 1;
        attr.cap.max_recv_wr = ISERT_QP_MAX_RECV_DTOS + 1;
        factor = rdma_rw_mr_factor(device->ib_device, cma_id->port_num,
                                   isert_sg_tablesize);
        attr.cap.max_rdma_ctxs = ISCSI_DEF_XMIT_CMDS_MAX * factor;
        attr.cap.max_send_sge = device->ib_device->attrs.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_INTEGRITY_EN;

        ret = rdma_create_qp(cma_id, device->pd, &attr);
        if (ret) {
                isert_err("rdma_create_qp failed for cma_id %d\n", ret);
                ib_cq_pool_put(isert_conn->cq, isert_conn->cq_size);

                return ERR_PTR(ret);
        }

        return cma_id->qp;
}

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 = kcalloc(ISERT_QP_MAX_RECV_DTOS,
                                       sizeof(struct iser_rx_desc),
                                       GFP_KERNEL);
        if (!isert_conn->rx_descs)
                return -ENOMEM;

        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, rx_desc->buf,
                                        ISER_RX_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 + isert_get_hdr_offset(rx_desc);
                rx_sg->length = ISER_RX_PAYLOAD_SIZE;
                rx_sg->lkey = device->pd->local_dma_lkey;
                rx_desc->rx_cqe.done = isert_recv_done;
        }

        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_SIZE, DMA_FROM_DEVICE);
        }
        kfree(isert_conn->rx_descs);
        isert_conn->rx_descs = NULL;
        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_SIZE, DMA_FROM_DEVICE);
        }

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

static int
isert_create_device_ib_res(struct isert_device *device)
{
        struct ib_device *ib_dev = device->ib_device;
        int ret;

        isert_dbg("devattr->max_send_sge: %d devattr->max_recv_sge %d\n",
                  ib_dev->attrs.max_send_sge, ib_dev->attrs.max_recv_sge);
        isert_dbg("devattr->max_sge_rd: %d\n", ib_dev->attrs.max_sge_rd);

        device->pd = ib_alloc_pd(ib_dev, 0);
        if (IS_ERR(device->pd)) {
                ret = PTR_ERR(device->pd);
                isert_err("failed to allocate pd, device %p, ret=%d\n",
                          device, ret);
                return ret;
        }

        /* Check signature cap */
        if (ib_dev->attrs.device_cap_flags & IB_DEVICE_INTEGRITY_HANDOVER)
                device->pi_capable = true;
        else
                device->pi_capable = false;

        return 0;
}

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

        ib_dealloc_pd(device->pd);
}

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_init_conn(struct isert_conn *isert_conn)
{
        isert_conn->state = ISER_CONN_INIT;
        INIT_LIST_HEAD(&isert_conn->node);
        init_completion(&isert_conn->login_comp);
        init_completion(&isert_conn->login_req_comp);
        init_waitqueue_head(&isert_conn->rem_wait);
        kref_init(&isert_conn->kref);
        mutex_init(&isert_conn->mutex);
        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_PAYLOAD_SIZE, DMA_TO_DEVICE);
        kfree(isert_conn->login_rsp_buf);

        ib_dma_unmap_single(ib_dev, isert_conn->login_desc->dma_addr,
                            ISER_RX_SIZE, DMA_FROM_DEVICE);
        kfree(isert_conn->login_desc);
}

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

        isert_conn->login_desc = kzalloc(sizeof(*isert_conn->login_desc),
                        GFP_KERNEL);
        if (!isert_conn->login_desc)
                return -ENOMEM;

        isert_conn->login_desc->dma_addr = ib_dma_map_single(ib_dev,
                                isert_conn->login_desc->buf,
                                ISER_RX_SIZE, DMA_FROM_DEVICE);
        ret = ib_dma_mapping_error(ib_dev, isert_conn->login_desc->dma_addr);
        if (ret) {
                isert_err("login_desc dma mapping error: %d\n", ret);
                isert_conn->login_desc->dma_addr = 0;
                goto out_free_login_desc;
        }

        isert_conn->login_rsp_buf = kzalloc(ISER_RX_PAYLOAD_SIZE, GFP_KERNEL);
        if (!isert_conn->login_rsp_buf) {
                ret = -ENOMEM;
                goto out_unmap_login_desc;
        }

        isert_conn->login_rsp_dma = ib_dma_map_single(ib_dev,
                                        isert_conn->login_rsp_buf,
                                        ISER_RX_PAYLOAD_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_free_login_rsp_buf;
        }

        return 0;

out_free_login_rsp_buf:
        kfree(isert_conn->login_rsp_buf);
out_unmap_login_desc:
        ib_dma_unmap_single(ib_dev, isert_conn->login_desc->dma_addr,
                            ISER_RX_SIZE, DMA_FROM_DEVICE);
out_free_login_desc:
        kfree(isert_conn->login_desc);
        return ret;
}

static void
isert_set_nego_params(struct isert_conn *isert_conn,
                      struct rdma_conn_param *param)
{
        struct ib_device_attr *attr = &isert_conn->device->ib_device->attrs;

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

        if (param->private_data) {
                u8 flags = *(u8 *)param->private_data;

                /*
                 * use remote invalidation if the both initiator
                 * and the HCA support it
                 */
                isert_conn->snd_w_inv = !(flags & ISER_SEND_W_INV_NOT_SUP) &&
                                          (attr->device_cap_flags &
                                           IB_DEVICE_MEM_MGT_EXTENSIONS);
                if (isert_conn->snd_w_inv)
                        isert_info("Using remote invalidation\n");
        }
}

static void
isert_destroy_qp(struct isert_conn *isert_conn)
{
        ib_destroy_qp(isert_conn->qp);
        ib_cq_pool_put(isert_conn->cq, isert_conn->cq_size);
}

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, IB_CM_REJ_CONSUMER_DEFINED);
        }
        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;

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

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

        isert_set_nego_params(isert_conn, &event->param.conn);

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

        ret = isert_login_post_recv(isert_conn);
        if (ret)
                goto out_destroy_qp;

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

        mutex_lock(&isert_np->mutex);
        list_add_tail(&isert_conn->node, &isert_np->accepted);
        mutex_unlock(&isert_np->mutex);

        return 0;

out_destroy_qp:
        isert_destroy_qp(isert_conn);
out_rsp_dma_map:
        isert_free_login_buf(isert_conn);
out_conn_dev:
        isert_device_put(device);
out:
        kfree(isert_conn);
        rdma_reject(cma_id, NULL, 0, IB_CM_REJ_CONSUMER_DEFINED);
        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);

        isert_free_rx_descriptors(isert_conn);
        if (isert_conn->cm_id &&
            !isert_conn->dev_removed)
                rdma_destroy_id(isert_conn->cm_id);

        if (isert_conn->qp)
                isert_destroy_qp(isert_conn);

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

        isert_device_put(device);

        if (isert_conn->dev_removed)
                wake_up_interruptible(&isert_conn->rem_wait);
        else
                kfree(isert_conn);
}

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

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

        mutex_lock(&isert_conn->mutex);
        isert_conn->state = ISER_CONN_UP;
        kref_get(&isert_conn->kref);
        mutex_unlock(&isert_conn->mutex);

        mutex_lock(&isert_np->mutex);
        list_move_tail(&isert_conn->node, &isert_np->pending);
        mutex_unlock(&isert_np->mutex);

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

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);
}

static void
isert_handle_unbound_conn(struct isert_conn *isert_conn)
{
        struct isert_np *isert_np = isert_conn->cm_id->context;

        mutex_lock(&isert_np->mutex);
        if (!list_empty(&isert_conn->node)) {
                /*
                 * This means iscsi doesn't know this connection
                 * so schedule a cleanup ourselves
                 */
                list_del_init(&isert_conn->node);
                isert_put_conn(isert_conn);
                queue_work(isert_release_wq, &isert_conn->release_work);
        }
        mutex_unlock(&isert_np->mutex);
}

/**
 * isert_conn_terminate() - Initiate connection termination
 * @isert_conn: isert connection struct
 *
 * Notes:
 * In case the connection state is BOUND, 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;

        if (isert_conn->state >= ISER_CONN_TERMINATING)
                return;

        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);
}

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->cm_id = NULL;
                break;
        case RDMA_CM_EVENT_ADDR_CHANGE:
                isert_np->cm_id = isert_setup_id(isert_np);
                if (IS_ERR(isert_np->cm_id)) {
                        isert_err("isert np %p setup id failed: %ld\n",
                                  isert_np, PTR_ERR(isert_np->cm_id));
                        isert_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_conn *isert_conn = cma_id->qp->qp_context;

        mutex_lock(&isert_conn->mutex);
        switch (isert_conn->state) {
        case ISER_CONN_TERMINATING:
                break;
        case ISER_CONN_UP:
                isert_conn_terminate(isert_conn);
                ib_drain_qp(isert_conn->qp);
                isert_handle_unbound_conn(isert_conn);
                break;
        case ISER_CONN_BOUND:
        case ISER_CONN_FULL_FEATURE: /* FALLTHRU */
                iscsit_cause_connection_reinstatement(isert_conn->conn, 0);
                break;
        default:
                isert_warn("conn %p terminating in state %d\n",
                           isert_conn, isert_conn->state);
        }
        mutex_unlock(&isert_conn->mutex);

        return 0;
}

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

        ib_drain_qp(isert_conn->qp);
        list_del_init(&isert_conn->node);
        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)
{
        struct isert_np *isert_np = cma_id->context;
        struct isert_conn *isert_conn;
        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);

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

        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:
        case RDMA_CM_EVENT_DISCONNECTED:
        case RDMA_CM_EVENT_TIMEWAIT_EXIT:  /* FALLTHRU */
                ret = isert_disconnected_handler(cma_id, event->event);
                break;
        case RDMA_CM_EVENT_DEVICE_REMOVAL:
                isert_conn = cma_id->qp->qp_context;
                isert_conn->dev_removed = true;
                isert_disconnected_handler(cma_id, event->event);
                wait_event_interruptible(isert_conn->rem_wait,
                                         isert_conn->state == ISER_CONN_DOWN);
                kfree(isert_conn);
                /*
                 * return non-zero from the callback to destroy
                 * the rdma cm id
                 */
                return 1;
        case RDMA_CM_EVENT_REJECTED:
                isert_info("Connection rejected: %s\n",
                           rdma_reject_msg(cma_id, event->status));
                fallthrough;
        case RDMA_CM_EVENT_UNREACHABLE:
        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_recvm(struct isert_conn *isert_conn, u32 count)
{
        struct ib_recv_wr *rx_wr;
        int i, ret;
        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[i];

                rx_wr->wr_cqe = &rx_desc->rx_cqe;
                rx_wr->sg_list = &rx_desc->rx_sg;
                rx_wr->num_sge = 1;
                rx_wr->next = rx_wr + 1;
                rx_desc->in_use = false;
        }
        rx_wr--;
        rx_wr->next = NULL; /* mark end of work requests list */

        ret = ib_post_recv(isert_conn->qp, isert_conn->rx_wr, NULL);
        if (ret)
                isert_err("ib_post_recv() failed with ret: %d\n", ret);

        return ret;
}

static int
isert_post_recv(struct isert_conn *isert_conn, struct iser_rx_desc *rx_desc)
{
        struct ib_recv_wr rx_wr;
        int ret;

        if (!rx_desc->in_use) {
                /*
                 * if the descriptor is not in-use we already reposted it
                 * for recv, so just silently return
                 */
                return 0;
        }

        rx_desc->in_use = false;
        rx_wr.wr_cqe = &rx_desc->rx_cqe;
        rx_wr.sg_list = &rx_desc->rx_sg;
        rx_wr.num_sge = 1;
        rx_wr.next = NULL;

        ret = ib_post_recv(isert_conn->qp, &rx_wr, NULL);
        if (ret)
                isert_err("ib_post_recv() failed with ret: %d\n", ret);

        return ret;
}

static int
isert_login_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;
        int ret;

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

        tx_desc->tx_cqe.done = isert_login_send_done;

        send_wr.next    = NULL;
        send_wr.wr_cqe  = &tx_desc->tx_cqe;
        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, NULL);
        if (ret)
                isert_err("ib_post_send() failed, ret: %d\n", ret);

        return ret;
}

static void
__isert_create_send_desc(struct isert_device *device,
                         struct iser_tx_desc *tx_desc)
{

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

        tx_desc->num_sge = 1;

        if (tx_desc->tx_sg[0].lkey != device->pd->local_dma_lkey) {
                tx_desc->tx_sg[0].lkey = device->pd->local_dma_lkey;
                isert_dbg("tx_desc %p lkey mismatch, fixing\n", tx_desc);
        }
}

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);

        __isert_create_send_desc(device, 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->pd->local_dma_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;

        tx_desc->tx_cqe.done = isert_send_done;
        send_wr->wr_cqe = &tx_desc->tx_cqe;

        if (isert_conn->snd_w_inv && isert_cmd->inv_rkey) {
                send_wr->opcode  = IB_WR_SEND_WITH_INV;
                send_wr->ex.invalidate_rkey = isert_cmd->inv_rkey;
        } else {
                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_login_post_recv(struct isert_conn *isert_conn)
{
        struct ib_recv_wr rx_wr;
        struct ib_sge sge;
        int ret;

        memset(&sge, 0, sizeof(struct ib_sge));
        sge.addr = isert_conn->login_desc->dma_addr +
                isert_get_hdr_offset(isert_conn->login_desc);
        sge.length = ISER_RX_PAYLOAD_SIZE;
        sge.lkey = isert_conn->device->pd->local_dma_lkey;

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

        isert_conn->login_desc->rx_cqe.done = isert_login_recv_done;

        memset(&rx_wr, 0, sizeof(struct ib_recv_wr));
        rx_wr.wr_cqe = &isert_conn->login_desc->rx_cqe;
        rx_wr.sg_list = &sge;
        rx_wr.num_sge = 1;

        ret = ib_post_recv(isert_conn->qp, &rx_wr, NULL);
        if (ret)
                isert_err("ib_post_recv() failed: %d\n", ret);

        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(device, 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->pd->local_dma_lkey;
                tx_desc->num_sge = 2;
        }
        if (!login->login_failed) {
                if (login->login_complete) {
                        ret = isert_alloc_rx_descriptors(isert_conn);
                        if (ret)
                                return ret;

                        ret = isert_post_recvm(isert_conn,
                                               ISERT_QP_MAX_RECV_DTOS);
                        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_login_post_recv(isert_conn);
                if (ret)
                        return ret;
        }
post_send:
        ret = isert_login_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 = isert_conn->login_desc;
        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 *)isert_get_iscsi_hdr(rx_desc);
                /*
                 * 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], isert_get_iscsi_hdr(rx_desc), 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, isert_get_data(rx_desc), 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 iser_rx_desc *rx_desc)
{
        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;
        isert_cmd->rx_desc = rx_desc;

        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;
        int imm_data, imm_data_len, unsol_data, sg_nents, rc;
        bool dump_payload = false;
        unsigned int data_len;

        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;
        data_len = cmd->se_cmd.data_length;

        if (imm_data && imm_data_len == data_len)
                cmd->se_cmd.se_cmd_flags |= SCF_PASSTHROUGH_SG_TO_MEM_NOALLOC;
        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;

        if (imm_data_len != data_len) {
                sg_nents = max(1UL, DIV_ROUND_UP(imm_data_len, PAGE_SIZE));
                sg_copy_from_buffer(cmd->se_cmd.t_data_sg, sg_nents,
                                    isert_get_data(rx_desc), imm_data_len);
                isert_dbg("Copy Immediate sg_nents: %u imm_data_len: %d\n",
                          sg_nents, imm_data_len);
        } else {
                sg_init_table(&isert_cmd->sg, 1);
                cmd->se_cmd.t_data_sg = &isert_cmd->sg;
                cmd->se_cmd.t_data_nents = 1;
                sg_set_buf(&isert_cmd->sg, isert_get_data(rx_desc),
                                imm_data_len);
                isert_dbg("Transfer Immediate imm_data_len: %d\n",
                          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 && unsol_data)
                iscsit_set_unsolicited_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, isert_get_data(rx_desc), unsol_data_len);

        sg_copy_from_buffer(sg_start, sg_nents, isert_get_data(rx_desc),
                            unsol_data_len);

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

        /*
         * multiple data-outs on the same command can arrive -
         * so post the buffer before hand
         */
        return isert_post_recv(isert_conn, rx_desc);
}

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)
                        return -ENOMEM;
        }
        cmd->text_in_ptr = text_in;

        memcpy(cmd->text_in_ptr, isert_get_data(rx_desc), 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 = isert_get_iscsi_hdr(rx_desc);
        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, rx_desc);
                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;
                isert_cmd->inv_rkey = read_stag ? read_stag : write_stag;

                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, rx_desc);
                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, rx_desc);
                if (!cmd)
                        break;

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

                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_print_wc(struct ib_wc *wc, const char *type)
{
        if (wc->status != IB_WC_WR_FLUSH_ERR)
                isert_err("%s failure: %s (%d) vend_err %x\n", type,
                          ib_wc_status_msg(wc->status), wc->status,
                          wc->vendor_err);
        else
                isert_dbg("%s failure: %s (%d)\n", type,
                          ib_wc_status_msg(wc->status), wc->status);
}

static void
isert_recv_done(struct ib_cq *cq, struct ib_wc *wc)
{
        struct isert_conn *isert_conn = wc->qp->qp_context;
        struct ib_device *ib_dev = isert_conn->cm_id->device;
        struct iser_rx_desc *rx_desc = cqe_to_rx_desc(wc->wr_cqe);
        struct iscsi_hdr *hdr = isert_get_iscsi_hdr(rx_desc);
        struct iser_ctrl *iser_ctrl = isert_get_iser_hdr(rx_desc);
        uint64_t read_va = 0, write_va = 0;
        uint32_t read_stag = 0, write_stag = 0;

        if (unlikely(wc->status != IB_WC_SUCCESS)) {
                isert_print_wc(wc, "recv");
                if (wc->status != IB_WC_WR_FLUSH_ERR)
                        iscsit_cause_connection_reinstatement(isert_conn->conn, 0);
                return;
        }

        rx_desc->in_use = true;

        ib_dma_sync_single_for_cpu(ib_dev, rx_desc->dma_addr,
                        ISER_RX_SIZE, DMA_FROM_DEVICE);

        isert_dbg("DMA: 0x%llx, iSCSI opcode: 0x%02x, ITT: 0x%08x, flags: 0x%02x dlen: %d\n",
                 rx_desc->dma_addr, hdr->opcode, hdr->itt, hdr->flags,
                 (int)(wc->byte_len - ISER_HEADERS_LEN));

        switch (iser_ctrl->flags & 0xF0) {
        case ISCSI_CTRL:
                if (iser_ctrl->flags & ISER_RSV) {
                        read_stag = be32_to_cpu(iser_ctrl->read_stag);
                        read_va = be64_to_cpu(iser_ctrl->read_va);
                        isert_dbg("ISER_RSV: read_stag: 0x%x read_va: 0x%llx\n",
                                  read_stag, (unsigned long long)read_va);
                }
                if (iser_ctrl->flags & ISER_WSV) {
                        write_stag = be32_to_cpu(iser_ctrl->write_stag);
                        write_va = be64_to_cpu(iser_ctrl->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_ctrl->flags);
                break;
        }

        isert_rx_opcode(isert_conn, rx_desc,
                        read_stag, read_va, write_stag, write_va);

        ib_dma_sync_single_for_device(ib_dev, rx_desc->dma_addr,
                        ISER_RX_SIZE, DMA_FROM_DEVICE);
}

static void
isert_login_recv_done(struct ib_cq *cq, struct ib_wc *wc)
{
        struct isert_conn *isert_conn = wc->qp->qp_context;
        struct ib_device *ib_dev = isert_conn->device->ib_device;

        if (unlikely(wc->status != IB_WC_SUCCESS)) {
                isert_print_wc(wc, "login recv");
                return;
        }

        ib_dma_sync_single_for_cpu(ib_dev, isert_conn->login_desc->dma_addr,
                        ISER_RX_SIZE, DMA_FROM_DEVICE);

        isert_conn->login_req_len = wc->byte_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);

        ib_dma_sync_single_for_device(ib_dev, isert_conn->login_desc->dma_addr,
                                ISER_RX_SIZE, DMA_FROM_DEVICE);
}

static void
isert_rdma_rw_ctx_destroy(struct isert_cmd *cmd, struct isert_conn *conn)
{
        struct se_cmd *se_cmd = &cmd->iscsi_cmd->se_cmd;
        enum dma_data_direction dir = target_reverse_dma_direction(se_cmd);

        if (!cmd->rw.nr_ops)
                return;

        if (isert_prot_cmd(conn, se_cmd)) {
                rdma_rw_ctx_destroy_signature(&cmd->rw, conn->qp,
                                conn->cm_id->port_num, se_cmd->t_data_sg,
                                se_cmd->t_data_nents, se_cmd->t_prot_sg,
                                se_cmd->t_prot_nents, dir);
        } else {
                rdma_rw_ctx_destroy(&cmd->rw, conn->qp, conn->cm_id->port_num,
                                se_cmd->t_data_sg, se_cmd->t_data_nents, dir);
        }

        cmd->rw.nr_ops = 0;
}

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 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);
                        }
                }

                isert_rdma_rw_ctx_destroy(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;
                }
                fallthrough;
        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->sense_info = 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->sense_info,
                          mr_status.sig_err.expected,
                          mr_status.sig_err.actual);
                ret = 1;
        }

fail_mr_status:
        return ret;
}

static void
isert_rdma_write_done(struct ib_cq *cq, struct ib_wc *wc)
{
        struct isert_conn *isert_conn = wc->qp->qp_context;
        struct isert_device *device = isert_conn->device;
        struct iser_tx_desc *desc = cqe_to_tx_desc(wc->wr_cqe);
        struct isert_cmd *isert_cmd = tx_desc_to_cmd(desc);
        struct se_cmd *cmd = &isert_cmd->iscsi_cmd->se_cmd;
        int ret = 0;

        if (unlikely(wc->status != IB_WC_SUCCESS)) {
                isert_print_wc(wc, "rdma write");
                if (wc->status != IB_WC_WR_FLUSH_ERR)
                        iscsit_cause_connection_reinstatement(isert_conn->conn, 0);
                isert_completion_put(desc, isert_cmd, device->ib_device, true);
                return;
        }

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

        ret = isert_check_pi_status(cmd, isert_cmd->rw.reg->mr);
        isert_rdma_rw_ctx_destroy(isert_cmd, isert_conn);

        if (ret) {
                /*
                 * transport_generic_request_failure() expects to have
                 * plus two references to handle queue-full, so re-add
                 * one here as target-core will have already dropped
                 * it after the first isert_put_datain() callback.
                 */
                kref_get(&cmd->cmd_kref);
                transport_generic_request_failure(cmd, cmd->pi_err);
        } else {
                /*
                 * XXX: isert_put_response() failure is not retried.
                 */
                ret = isert_put_response(isert_conn->conn, isert_cmd->iscsi_cmd);
                if (ret)
                        pr_warn_ratelimited("isert_put_response() ret: %d\n", ret);
        }
}

static void
isert_rdma_read_done(struct ib_cq *cq, struct ib_wc *wc)
{
        struct isert_conn *isert_conn = wc->qp->qp_context;
        struct isert_device *device = isert_conn->device;
        struct iser_tx_desc *desc = cqe_to_tx_desc(wc->wr_cqe);
        struct isert_cmd *isert_cmd = tx_desc_to_cmd(desc);
        struct iscsi_cmd *cmd = isert_cmd->iscsi_cmd;
        struct se_cmd *se_cmd = &cmd->se_cmd;
        int ret = 0;

        if (unlikely(wc->status != IB_WC_SUCCESS)) {
                isert_print_wc(wc, "rdma read");
                if (wc->status != IB_WC_WR_FLUSH_ERR)
                        iscsit_cause_connection_reinstatement(isert_conn->conn, 0);
                isert_completion_put(desc, isert_cmd, device->ib_device, true);
                return;
        }

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

        iscsit_stop_dataout_timer(cmd);

        if (isert_prot_cmd(isert_conn, se_cmd))
                ret = isert_check_pi_status(se_cmd, isert_cmd->rw.reg->mr);
        isert_rdma_rw_ctx_destroy(isert_cmd, isert_conn);
        cmd->write_data_done = 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);

        /*
         * transport_generic_request_failure() will drop the extra
         * se_cmd->cmd_kref reference after T10-PI error, and handle
         * any non-zero ->queue_status() callback error retries.
         */
        if (ret)
                transport_generic_request_failure(se_cmd, se_cmd->pi_err);
        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);
                fallthrough;
        case ISTATE_SEND_REJECT:
        case ISTATE_SEND_TEXTRSP:
                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_login_send_done(struct ib_cq *cq, struct ib_wc *wc)
{
        struct isert_conn *isert_conn = wc->qp->qp_context;
        struct ib_device *ib_dev = isert_conn->cm_id->device;
        struct iser_tx_desc *tx_desc = cqe_to_tx_desc(wc->wr_cqe);

        if (unlikely(wc->status != IB_WC_SUCCESS)) {
                isert_print_wc(wc, "login send");
                if (wc->status != IB_WC_WR_FLUSH_ERR)
                        iscsit_cause_connection_reinstatement(isert_conn->conn, 0);
        }

        isert_unmap_tx_desc(tx_desc, ib_dev);
}

static void
isert_send_done(struct ib_cq *cq, struct ib_wc *wc)
{
        struct isert_conn *isert_conn = wc->qp->qp_context;
        struct ib_device *ib_dev = isert_conn->cm_id->device;
        struct iser_tx_desc *tx_desc = cqe_to_tx_desc(wc->wr_cqe);
        struct isert_cmd *isert_cmd = tx_desc_to_cmd(tx_desc);

        if (unlikely(wc->status != IB_WC_SUCCESS)) {
                isert_print_wc(wc, "send");
                if (wc->status != IB_WC_WR_FLUSH_ERR)
                        iscsit_cause_connection_reinstatement(isert_conn->conn, 0);
                isert_completion_put(tx_desc, isert_cmd, ib_dev, true);
                return;
        }

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

        switch (isert_cmd->iscsi_cmd->i_state) {
        case ISTATE_SEND_TASKMGTRSP:
        case ISTATE_SEND_LOGOUTRSP:
        case ISTATE_SEND_REJECT:
        case 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;
        default:
                isert_cmd->iscsi_cmd->i_state = ISTATE_SENT_STATUS;
                isert_completion_put(tx_desc, isert_cmd, ib_dev, false);
                break;
        }
}

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

        ret = isert_post_recv(isert_conn, isert_cmd->rx_desc);
        if (ret)
                return ret;

        ret = ib_post_send(isert_conn->qp, &isert_cmd->tx_desc.send_wr, NULL);
        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);
                if (ib_dma_mapping_error(ib_dev, isert_cmd->pdu_buf_dma))
                        return -ENOMEM;

                isert_cmd->pdu_buf_len = pdu_len;
                tx_dsg->addr    = isert_cmd->pdu_buf_dma;
                tx_dsg->length  = pdu_len;
                tx_dsg->lkey    = device->pd->local_dma_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;

        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);
        isert_rdma_rw_ctx_destroy(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);
        if (ib_dma_mapping_error(ib_dev, isert_cmd->pdu_buf_dma))
                return -ENOMEM;
        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->pd->local_dma_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);
                if (ib_dma_mapping_error(ib_dev, isert_cmd->pdu_buf_dma))
                        return -ENOMEM;

                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->pd->local_dma_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 inline void
isert_set_dif_domain(struct se_cmd *se_cmd, 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)
{

        memset(sig_attrs, 0, sizeof(*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->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->mem);
                break;
        case TARGET_PROT_DIN_PASS:
        case TARGET_PROT_DOUT_PASS:
                isert_set_dif_domain(se_cmd, &sig_attrs->wire);
                isert_set_dif_domain(se_cmd, &sig_attrs->mem);
                break;
        default:
                isert_err("Unsupported PI operation %d\n", se_cmd->prot_op);
                return -EINVAL;
        }

        if (se_cmd->prot_checks & TARGET_DIF_CHECK_GUARD)
                sig_attrs->check_mask |= IB_SIG_CHECK_GUARD;
        if (se_cmd->prot_checks & TARGET_DIF_CHECK_APPTAG)
                sig_attrs->check_mask |= IB_SIG_CHECK_APPTAG;
        if (se_cmd->prot_checks & TARGET_DIF_CHECK_REFTAG)
                sig_attrs->check_mask |= IB_SIG_CHECK_REFTAG;

        return 0;
}

static int
isert_rdma_rw_ctx_post(struct isert_cmd *cmd, struct isert_conn *conn,
                struct ib_cqe *cqe, struct ib_send_wr *chain_wr)
{
        struct se_cmd *se_cmd = &cmd->iscsi_cmd->se_cmd;
        enum dma_data_direction dir = target_reverse_dma_direction(se_cmd);
        u8 port_num = conn->cm_id->port_num;
        u64 addr;
        u32 rkey, offset;
        int ret;

        if (cmd->ctx_init_done)
                goto rdma_ctx_post;

        if (dir == DMA_FROM_DEVICE) {
                addr = cmd->write_va;
                rkey = cmd->write_stag;
                offset = cmd->iscsi_cmd->write_data_done;
        } else {
                addr = cmd->read_va;
                rkey = cmd->read_stag;
                offset = 0;
        }

        if (isert_prot_cmd(conn, se_cmd)) {
                struct ib_sig_attrs sig_attrs;

                ret = isert_set_sig_attrs(se_cmd, &sig_attrs);
                if (ret)
                        return ret;

                WARN_ON_ONCE(offset);
                ret = rdma_rw_ctx_signature_init(&cmd->rw, conn->qp, port_num,
                                se_cmd->t_data_sg, se_cmd->t_data_nents,
                                se_cmd->t_prot_sg, se_cmd->t_prot_nents,
                                &sig_attrs, addr, rkey, dir);
        } else {
                ret = rdma_rw_ctx_init(&cmd->rw, conn->qp, port_num,
                                se_cmd->t_data_sg, se_cmd->t_data_nents,
                                offset, addr, rkey, dir);
        }

        if (ret < 0) {
                isert_err("Cmd: %p failed to prepare RDMA res\n", cmd);
                return ret;
        }

        cmd->ctx_init_done = true;

rdma_ctx_post:
        ret = rdma_rw_ctx_post(&cmd->rw, conn->qp, port_num, cqe, chain_wr);
        if (ret < 0)
                isert_err("Cmd: %p failed to post RDMA res\n", cmd);
        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_conn *isert_conn = conn->context;
        struct ib_cqe *cqe = NULL;
        struct ib_send_wr *chain_wr = NULL;
        int rc;

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

        if (isert_prot_cmd(isert_conn, se_cmd)) {
                isert_cmd->tx_desc.tx_cqe.done = isert_rdma_write_done;
                cqe = &isert_cmd->tx_desc.tx_cqe;
        } else {
                /*
                 * 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);

                rc = isert_post_recv(isert_conn, isert_cmd->rx_desc);
                if (rc)
                        return rc;

                chain_wr = &isert_cmd->tx_desc.send_wr;
        }

        rc = isert_rdma_rw_ctx_post(isert_cmd, isert_conn, cqe, chain_wr);
        isert_dbg("Cmd: %p posted RDMA_WRITE for iSER Data READ rc: %d\n",
                  isert_cmd, rc);
        return rc;
}

static int
isert_get_dataout(struct iscsi_conn *conn, struct iscsi_cmd *cmd, bool recovery)
{
        struct isert_cmd *isert_cmd = iscsit_priv_cmd(cmd);
        int ret;

        isert_dbg("Cmd: %p RDMA_READ data_length: %u write_data_done: %u\n",
                 isert_cmd, cmd->se_cmd.data_length, cmd->write_data_done);

        isert_cmd->tx_desc.tx_cqe.done = isert_rdma_read_done;
        ret = isert_rdma_rw_ctx_post(isert_cmd, conn->context,
                                     &isert_cmd->tx_desc.tx_cqe, NULL);

        isert_dbg("Cmd: %p posted RDMA_READ memory for ISER Data WRITE rc: %d\n",
                 isert_cmd, ret);
        return ret;
}

static int
isert_immediate_queue(struct iscsi_conn *conn, struct iscsi_cmd *cmd, int state)
{
        struct isert_cmd *isert_cmd = iscsit_priv_cmd(cmd);
        int ret = 0;

        switch (state) {
        case ISTATE_REMOVE:
                spin_lock_bh(&conn->cmd_lock);
                list_del_init(&cmd->i_conn_node);
                spin_unlock_bh(&conn->cmd_lock);
                isert_put_cmd(isert_cmd, true);
                break;
        case ISTATE_SEND_NOPIN_WANT_RESPONSE:
                ret = isert_put_nopin(cmd, conn, false);
                break;
        default:
                isert_err("Unknown immediate state: 0x%02x\n", state);
                ret = -EINVAL;
                break;
        }

        return ret;
}

static int
isert_response_queue(struct iscsi_conn *conn, struct iscsi_cmd *cmd, int state)
{
        struct isert_conn *isert_conn = conn->context;
        int ret;

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

        return ret;
}

struct rdma_cm_id *
isert_setup_id(struct isert_np *isert_np)
{
        struct iscsi_np *np = isert_np->np;
        struct rdma_cm_id *id;
        struct sockaddr *sa;
        int ret;

        sa = (struct sockaddr *)&np->np_sockaddr;
        isert_dbg("ksockaddr: %p, sa: %p\n", &np->np_sockaddr, sa);

        id = rdma_create_id(&init_net, isert_cma_handler, isert_np,
                            RDMA_PS_TCP, IB_QPT_RC);
        if (IS_ERR(id)) {
                isert_err("rdma_create_id() failed: %ld\n", PTR_ERR(id));
                ret = PTR_ERR(id);
                goto out;
        }
        isert_dbg("id %p context %p\n", id, id->context);

        /*
         * Allow both IPv4 and IPv6 sockets to bind a single port
         * at the same time.
         */
        ret = rdma_set_afonly(id, 1);
        if (ret) {
                isert_err("rdma_set_afonly() failed: %d\n", ret);
                goto out_id;
        }

        ret = rdma_bind_addr(id, sa);
        if (ret) {
                isert_err("rdma_bind_addr() failed: %d\n", ret);
                goto out_id;
        }

        ret = rdma_listen(id, 0);
        if (ret) {
                isert_err("rdma_listen() failed: %d\n", ret);
                goto out_id;
        }

        return id;
out_id:
        rdma_destroy_id(id);
out:
        return ERR_PTR(ret);
}

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

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

        sema_init(&isert_np->sem, 0);
        mutex_init(&isert_np->mutex);
        INIT_LIST_HEAD(&isert_np->accepted);
        INIT_LIST_HEAD(&isert_np->pending);
        isert_np->np = np;

        /*
         * Setup the np->np_sockaddr from the passed sockaddr setup
         * in iscsi_target_configfs.c code..
         */
        memcpy(&np->np_sockaddr, ksockaddr,
               sizeof(struct sockaddr_storage));

        isert_lid = isert_setup_id(isert_np);
        if (IS_ERR(isert_lid)) {
                ret = PTR_ERR(isert_lid);
                goto out;
        }

        isert_np->cm_id = isert_lid;
        np->np_context = isert_np;

        return 0;

out:
        kfree(isert_np);

        return ret;
}

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

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

        memset(&rsp_hdr, 0, sizeof(rsp_hdr));
        rsp_hdr.flags = ISERT_ZBVA_NOT_USED;
        if (!isert_conn->snd_w_inv)
                rsp_hdr.flags = rsp_hdr.flags | ISERT_SEND_W_INV_NOT_USED;
        cp.private_data = (void *)&rsp_hdr;
        cp.private_data_len = sizeof(rsp_hdr);

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

        return 0;
}

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

        isert_info("before login_req comp conn: %p\n", isert_conn);
        ret = wait_for_completion_interruptible(&isert_conn->login_req_comp);
        if (ret) {
                isert_err("isert_conn %p interrupted before got login req\n",
                          isert_conn);
                return ret;
        }
        reinit_completion(&isert_conn->login_req_comp);

        /*
         * For login requests after the first PDU, isert_rx_login_req() will
         * kick schedule_delayed_work(&conn->login_work) as the packet is
         * received, which turns this callback from iscsi_target_do_login_rx()
         * into a NOP.
         */
        if (!login->first_request)
                return 0;

        isert_rx_login_req(isert_conn);

        isert_info("before login_comp conn: %p\n", conn);
        ret = wait_for_completion_interruptible(&isert_conn->login_comp);
        if (ret)
                return ret;

        isert_info("processing login->req: %p\n", login->req);

        return 0;
}

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

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

        conn->login_sockaddr = cm_route->addr.dst_addr;
        conn->local_sockaddr = cm_route->addr.src_addr;
}

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

accept_wait:
        ret = down_interruptible(&isert_np->sem);
        if (ret)
                return -ENODEV;

        spin_lock_bh(&np->np_thread_lock);
        if (np->np_thread_state >= ISCSI_NP_THREAD_RESET) {
                spin_unlock_bh(&np->np_thread_lock);
                isert_dbg("np_thread_state %d\n",
                         np->np_thread_state);
                /*
                 * No point in stalling here when np_thread
                 * is in state RESET/SHUTDOWN/EXIT - bail
                 */
                return -ENODEV;
        }
        spin_unlock_bh(&np->np_thread_lock);

        mutex_lock(&isert_np->mutex);
        if (list_empty(&isert_np->pending)) {
                mutex_unlock(&isert_np->mutex);
                goto accept_wait;
        }
        isert_conn = list_first_entry(&isert_np->pending,
                        struct isert_conn, node);
        list_del_init(&isert_conn->node);
        mutex_unlock(&isert_np->mutex);

        conn->context = isert_conn;
        isert_conn->conn = conn;
        isert_conn->state = ISER_CONN_BOUND;

        isert_set_conn_info(np, conn, isert_conn);

        isert_dbg("Processing isert_conn: %p\n", isert_conn);

        return 0;
}

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

        if (isert_np->cm_id)
                rdma_destroy_id(isert_np->cm_id);

        /*
         * FIXME: At this point we don't have a good way to insure
         * that at this point we don't have hanging connections that
         * completed RDMA establishment but didn't start iscsi login
         * process. So work-around this by cleaning up what ever piled
         * up in accepted and pending lists.
         */
        mutex_lock(&isert_np->mutex);
        if (!list_empty(&isert_np->pending)) {
                isert_info("Still have isert pending connections\n");
                list_for_each_entry_safe(isert_conn, n,
                                         &isert_np->pending,
                                         node) {
                        isert_info("cleaning isert_conn %p state (%d)\n",
                                   isert_conn, isert_conn->state);
                        isert_connect_release(isert_conn);
                }
        }

        if (!list_empty(&isert_np->accepted)) {
                isert_info("Still have isert accepted connections\n");
                list_for_each_entry_safe(isert_conn, n,
                                         &isert_np->accepted,
                                         node) {
                        isert_info("cleaning isert_conn %p state (%d)\n",
                                   isert_conn, isert_conn->state);
                        isert_connect_release(isert_conn);
                }
        }
        mutex_unlock(&isert_np->mutex);

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

static void isert_release_work(struct work_struct *work)
{
        struct isert_conn *isert_conn = container_of(work,
                                                     struct isert_conn,
                                                     release_work);

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

        mutex_lock(&isert_conn->mutex);
        isert_conn->state = ISER_CONN_DOWN;
        mutex_unlock(&isert_conn->mutex);

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

static void
isert_wait4logout(struct isert_conn *isert_conn)
{
        struct iscsi_conn *conn = isert_conn->conn;

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

        if (isert_conn->logout_posted) {
                isert_info("conn %p wait for conn_logout_comp\n", isert_conn);
                wait_for_completion_timeout(&conn->conn_logout_comp,
                                            SECONDS_FOR_LOGOUT_COMP * HZ);
        }
}

static void
isert_wait4cmds(struct iscsi_conn *conn)
{
        isert_info("iscsi_conn %p\n", conn);

        if (conn->sess) {
                target_stop_session(conn->sess->se_sess);
                target_wait_for_sess_cmds(conn->sess->se_sess);
        }
}

/**
 * isert_put_unsol_pending_cmds() - Drop commands waiting for
 *     unsolicitate dataout
 * @conn:    iscsi connection
 *
 * We might still have commands that are waiting for unsolicited
 * dataouts messages. We must put the extra reference on those
 * before blocking on the target_wait_for_session_cmds
 */
static void
isert_put_unsol_pending_cmds(struct iscsi_conn *conn)
{
        struct iscsi_cmd *cmd, *tmp;
        static LIST_HEAD(drop_cmd_list);

        spin_lock_bh(&conn->cmd_lock);
        list_for_each_entry_safe(cmd, tmp, &conn->conn_cmd_list, i_conn_node) {
                if ((cmd->cmd_flags & ICF_NON_IMMEDIATE_UNSOLICITED_DATA) &&
                    (cmd->write_data_done < conn->sess->sess_ops->FirstBurstLength) &&
                    (cmd->write_data_done < cmd->se_cmd.data_length))
                        list_move_tail(&cmd->i_conn_node, &drop_cmd_list);
        }
        spin_unlock_bh(&conn->cmd_lock);

        list_for_each_entry_safe(cmd, tmp, &drop_cmd_list, i_conn_node) {
                list_del_init(&cmd->i_conn_node);
                if (cmd->i_state != ISTATE_REMOVE) {
                        struct isert_cmd *isert_cmd = iscsit_priv_cmd(cmd);

                        isert_info("conn %p dropping cmd %p\n", conn, cmd);
                        isert_put_cmd(isert_cmd, true);
                }
        }
}

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

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

        mutex_lock(&isert_conn->mutex);
        isert_conn_terminate(isert_conn);
        mutex_unlock(&isert_conn->mutex);

        ib_drain_qp(isert_conn->qp);
        isert_put_unsol_pending_cmds(conn);
        isert_wait4cmds(conn);
        isert_wait4logout(isert_conn);

        queue_work(isert_release_wq, &isert_conn->release_work);
}

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

        ib_drain_qp(isert_conn->qp);
        isert_put_conn(isert_conn);
}

static void isert_get_rx_pdu(struct iscsi_conn *conn)
{
        struct completion comp;

        init_completion(&comp);

        wait_for_completion_interruptible(&comp);
}

static struct iscsit_transport iser_target_transport = {
        .name                   = "IB/iSER",
        .transport_type         = ISCSI_INFINIBAND,
        .rdma_shutdown          = true,
        .priv_size              = sizeof(struct isert_cmd),
        .owner                  = THIS_MODULE,
        .iscsit_setup_np        = isert_setup_np,
        .iscsit_accept_np       = isert_accept_np,
        .iscsit_free_np         = isert_free_np,
        .iscsit_wait_conn       = isert_wait_conn,
        .iscsit_free_conn       = isert_free_conn,
        .iscsit_get_login_rx    = isert_get_login_rx,
        .iscsit_put_login_tx    = isert_put_login_tx,
        .iscsit_immediate_queue = isert_immediate_queue,
        .iscsit_response_queue  = isert_response_queue,
        .iscsit_get_dataout     = isert_get_dataout,
        .iscsit_queue_data_in   = isert_put_datain,
        .iscsit_queue_status    = isert_put_response,
        .iscsit_aborted_task    = isert_aborted_task,
        .iscsit_get_rx_pdu      = isert_get_rx_pdu,
        .iscsit_get_sup_prot_ops = isert_get_sup_prot_ops,
};

static int __init isert_init(void)
{
        int ret;

        isert_comp_wq = alloc_workqueue("isert_comp_wq",
                                        WQ_UNBOUND | WQ_HIGHPRI, 0);
        if (!isert_comp_wq) {
                isert_err("Unable to allocate isert_comp_wq\n");
                return -ENOMEM;
        }

        isert_release_wq = alloc_workqueue("isert_release_wq", WQ_UNBOUND,
                                        WQ_UNBOUND_MAX_ACTIVE);
        if (!isert_release_wq) {
                isert_err("Unable to allocate isert_release_wq\n");
                ret = -ENOMEM;
                goto destroy_comp_wq;
        }

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

        return 0;

destroy_comp_wq:
        destroy_workqueue(isert_comp_wq);

        return ret;
}

static void __exit isert_exit(void)
{
        flush_scheduled_work();
        destroy_workqueue(isert_release_wq);
        destroy_workqueue(isert_comp_wq);
        iscsit_unregister_transport(&iser_target_transport);
        isert_info("iSER_TARGET[0] - Released iser_target_transport\n");
}

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

module_init(isert_init);
module_exit(isert_exit);