/*
 * Copyright (c) 2004, 2005, 2006 Voltaire, Inc. All rights reserved.
 * Copyright (c) 2005, 2006 Cisco Systems.  All rights reserved.
 * Copyright (c) 2013 Mellanox Technologies. All rights reserved.
 *
 * This software is available to you under a choice of one of two
 * licenses.  You may choose to be licensed under the terms of the GNU
 * General Public License (GPL) Version 2, available from the file
 * COPYING in the main directory of this source tree, or the
 * OpenIB.org BSD license below:
 *
 *     Redistribution and use in source and binary forms, with or
 *     without modification, are permitted provided that the following
 *     conditions are met:
 *
 *      - Redistributions of source code must retain the above
 *        copyright notice, this list of conditions and the following
 *        disclaimer.
 *
 *      - Redistributions in binary form must reproduce the above
 *        copyright notice, this list of conditions and the following
 *        disclaimer in the documentation and/or other materials
 *        provided with the distribution.
 *
 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
 * EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
 * MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
 * NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS
 * BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN
 * ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN
 * CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
 * SOFTWARE.
 */
#include <linux/kernel.h>
#include <linux/module.h>
#include <linux/slab.h>
#include <linux/delay.h>

#include "iscsi_iser.h"

#define ISCSI_ISER_MAX_CONN     8
#define ISER_MAX_RX_CQ_LEN      (ISER_QP_MAX_RECV_DTOS * ISCSI_ISER_MAX_CONN)
#define ISER_MAX_TX_CQ_LEN      (ISER_QP_MAX_REQ_DTOS  * ISCSI_ISER_MAX_CONN)

static void iser_cq_tasklet_fn(unsigned long data);
static void iser_cq_callback(struct ib_cq *cq, void *cq_context);

static void iser_cq_event_callback(struct ib_event *cause, void *context)
{
        iser_err("got cq event %d \n", cause->event);
}

static void iser_qp_event_callback(struct ib_event *cause, void *context)
{
        iser_err("got qp event %d\n",cause->event);
}

static void iser_event_handler(struct ib_event_handler *handler,
                                struct ib_event *event)
{
        iser_err("async event %d on device %s port %d\n", event->event,
                event->device->name, event->element.port_num);
}

/**
 * iser_create_device_ib_res - creates Protection Domain (PD), Completion
 * Queue (CQ), DMA Memory Region (DMA MR) with the device associated with
 * the adapator.
 *
 * returns 0 on success, -1 on failure
 */
static int iser_create_device_ib_res(struct iser_device *device)
{
        int i, j;
        struct iser_cq_desc *cq_desc;
        struct ib_device_attr *dev_attr;

        dev_attr = kmalloc(sizeof(*dev_attr), GFP_KERNEL);
        if (!dev_attr)
                return -ENOMEM;

        if (ib_query_device(device->ib_device, dev_attr)) {
                pr_warn("Query device failed for %s\n", device->ib_device->name);
                goto dev_attr_err;
        }

        /* Assign function handles  - based on FMR support */
        if (device->ib_device->alloc_fmr && device->ib_device->dealloc_fmr &&
            device->ib_device->map_phys_fmr && device->ib_device->unmap_fmr) {
                iser_info("FMR supported, using FMR for registration\n");
                device->iser_alloc_rdma_reg_res = iser_create_fmr_pool;
                device->iser_free_rdma_reg_res = iser_free_fmr_pool;
                device->iser_reg_rdma_mem = iser_reg_rdma_mem_fmr;
                device->iser_unreg_rdma_mem = iser_unreg_mem_fmr;
        } else
        if (dev_attr->device_cap_flags & IB_DEVICE_MEM_MGT_EXTENSIONS) {
                iser_info("FRWR supported, using FRWR for registration\n");
                device->iser_alloc_rdma_reg_res = iser_create_frwr_pool;
                device->iser_free_rdma_reg_res = iser_free_frwr_pool;
                device->iser_reg_rdma_mem = iser_reg_rdma_mem_frwr;
                device->iser_unreg_rdma_mem = iser_unreg_mem_frwr;
        } else {
                iser_err("IB device does not support FMRs nor FRWRs, can't register memory\n");
                goto dev_attr_err;
        }

        device->cqs_used = min(ISER_MAX_CQ, device->ib_device->num_comp_vectors);
        iser_info("using %d CQs, device %s supports %d vectors\n",
                  device->cqs_used, device->ib_device->name,
                  device->ib_device->num_comp_vectors);

        device->cq_desc = kmalloc(sizeof(struct iser_cq_desc) * device->cqs_used,
                                  GFP_KERNEL);
        if (device->cq_desc == NULL)
                goto cq_desc_err;
        cq_desc = device->cq_desc;

        device->pd = ib_alloc_pd(device->ib_device);
        if (IS_ERR(device->pd))
                goto pd_err;

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

                device->rx_cq[i] = ib_create_cq(device->ib_device,
                                          iser_cq_callback,
                                          iser_cq_event_callback,
                                          (void *)&cq_desc[i],
                                          ISER_MAX_RX_CQ_LEN, i);
                if (IS_ERR(device->rx_cq[i]))
                        goto cq_err;

                device->tx_cq[i] = ib_create_cq(device->ib_device,
                                          NULL, iser_cq_event_callback,
                                          (void *)&cq_desc[i],
                                          ISER_MAX_TX_CQ_LEN, i);

                if (IS_ERR(device->tx_cq[i]))
                        goto cq_err;

                if (ib_req_notify_cq(device->rx_cq[i], IB_CQ_NEXT_COMP))
                        goto cq_err;

                tasklet_init(&device->cq_tasklet[i],
                             iser_cq_tasklet_fn,
                        (unsigned long)&cq_desc[i]);
        }

        device->mr = ib_get_dma_mr(device->pd, IB_ACCESS_LOCAL_WRITE |
                                   IB_ACCESS_REMOTE_WRITE |
                                   IB_ACCESS_REMOTE_READ);
        if (IS_ERR(device->mr))
                goto dma_mr_err;

        INIT_IB_EVENT_HANDLER(&device->event_handler, device->ib_device,
                                iser_event_handler);
        if (ib_register_event_handler(&device->event_handler))
                goto handler_err;

        kfree(dev_attr);
        return 0;

handler_err:
        ib_dereg_mr(device->mr);
dma_mr_err:
        for (j = 0; j < device->cqs_used; j++)
                tasklet_kill(&device->cq_tasklet[j]);
cq_err:
        for (j = 0; j < i; j++) {
                if (device->tx_cq[j])
                        ib_destroy_cq(device->tx_cq[j]);
                if (device->rx_cq[j])
                        ib_destroy_cq(device->rx_cq[j]);
        }
        ib_dealloc_pd(device->pd);
pd_err:
        kfree(device->cq_desc);
cq_desc_err:
        iser_err("failed to allocate an IB resource\n");
dev_attr_err:
        kfree(dev_attr);
        return -1;
}

/**
 * iser_free_device_ib_res - destroy/dealloc/dereg the DMA MR,
 * CQ and PD created with the device associated with the adapator.
 */
static void iser_free_device_ib_res(struct iser_device *device)
{
        int i;
        BUG_ON(device->mr == NULL);

        for (i = 0; i < device->cqs_used; i++) {
                tasklet_kill(&device->cq_tasklet[i]);
                (void)ib_destroy_cq(device->tx_cq[i]);
                (void)ib_destroy_cq(device->rx_cq[i]);
                device->tx_cq[i] = NULL;
                device->rx_cq[i] = NULL;
        }

        (void)ib_unregister_event_handler(&device->event_handler);
        (void)ib_dereg_mr(device->mr);
        (void)ib_dealloc_pd(device->pd);

        kfree(device->cq_desc);

        device->mr = NULL;
        device->pd = NULL;
}

/**
 * iser_create_fmr_pool - Creates FMR pool and page_vector
 *
 * returns 0 on success, or errno code on failure
 */
int iser_create_fmr_pool(struct iser_conn *ib_conn, unsigned cmds_max)
{
        struct iser_device *device = ib_conn->device;
        struct ib_fmr_pool_param params;
        int ret = -ENOMEM;

        ib_conn->fastreg.fmr.page_vec = kmalloc(sizeof(struct iser_page_vec) +
                                                (sizeof(u64)*(ISCSI_ISER_SG_TABLESIZE + 1)),
                                                GFP_KERNEL);
        if (!ib_conn->fastreg.fmr.page_vec)
                return ret;

        ib_conn->fastreg.fmr.page_vec->pages = (u64 *)(ib_conn->fastreg.fmr.page_vec + 1);

        params.page_shift        = SHIFT_4K;
        /* when the first/last SG element are not start/end *
         * page aligned, the map whould be of N+1 pages     */
        params.max_pages_per_fmr = ISCSI_ISER_SG_TABLESIZE + 1;
        /* make the pool size twice the max number of SCSI commands *
         * the ML is expected to queue, watermark for unmap at 50%  */
        params.pool_size         = cmds_max * 2;
        params.dirty_watermark   = cmds_max;
        params.cache             = 0;
        params.flush_function    = NULL;
        params.access            = (IB_ACCESS_LOCAL_WRITE  |
                                    IB_ACCESS_REMOTE_WRITE |
                                    IB_ACCESS_REMOTE_READ);

        ib_conn->fastreg.fmr.pool = ib_create_fmr_pool(device->pd, &params);
        if (!IS_ERR(ib_conn->fastreg.fmr.pool))
                return 0;

        /* no FMR => no need for page_vec */
        kfree(ib_conn->fastreg.fmr.page_vec);
        ib_conn->fastreg.fmr.page_vec = NULL;

        ret = PTR_ERR(ib_conn->fastreg.fmr.pool);
        ib_conn->fastreg.fmr.pool = NULL;
        if (ret != -ENOSYS) {
                iser_err("FMR allocation failed, err %d\n", ret);
                return ret;
        } else {
                iser_warn("FMRs are not supported, using unaligned mode\n");
                return 0;
        }
}

/**
 * iser_free_fmr_pool - releases the FMR pool and page vec
 */
void iser_free_fmr_pool(struct iser_conn *ib_conn)
{
        iser_info("freeing conn %p fmr pool %p\n",
                  ib_conn, ib_conn->fastreg.fmr.pool);

        if (ib_conn->fastreg.fmr.pool != NULL)
                ib_destroy_fmr_pool(ib_conn->fastreg.fmr.pool);

        ib_conn->fastreg.fmr.pool = NULL;

        kfree(ib_conn->fastreg.fmr.page_vec);
        ib_conn->fastreg.fmr.page_vec = NULL;
}

/**
 * iser_create_frwr_pool - Creates pool of fast_reg descriptors
 * for fast registration work requests.
 * returns 0 on success, or errno code on failure
 */
int iser_create_frwr_pool(struct iser_conn *ib_conn, unsigned cmds_max)
{
        struct iser_device      *device = ib_conn->device;
        struct fast_reg_descriptor      *desc;
        int i, ret;

        INIT_LIST_HEAD(&ib_conn->fastreg.frwr.pool);
        ib_conn->fastreg.frwr.pool_size = 0;
        for (i = 0; i < cmds_max; i++) {
                desc = kmalloc(sizeof(*desc), GFP_KERNEL);
                if (!desc) {
                        iser_err("Failed to allocate a new fast_reg descriptor\n");
                        ret = -ENOMEM;
                        goto err;
                }

                desc->data_frpl = ib_alloc_fast_reg_page_list(device->ib_device,
                                                         ISCSI_ISER_SG_TABLESIZE + 1);
                if (IS_ERR(desc->data_frpl)) {
                        ret = PTR_ERR(desc->data_frpl);
                        iser_err("Failed to allocate ib_fast_reg_page_list err=%d\n", ret);
                        goto fast_reg_page_failure;
                }

                desc->data_mr = ib_alloc_fast_reg_mr(device->pd,
                                                     ISCSI_ISER_SG_TABLESIZE + 1);
                if (IS_ERR(desc->data_mr)) {
                        ret = PTR_ERR(desc->data_mr);
                        iser_err("Failed to allocate ib_fast_reg_mr err=%d\n", ret);
                        goto fast_reg_mr_failure;
                }
                desc->valid = true;
                list_add_tail(&desc->list, &ib_conn->fastreg.frwr.pool);
                ib_conn->fastreg.frwr.pool_size++;
        }

        return 0;

fast_reg_mr_failure:
        ib_free_fast_reg_page_list(desc->data_frpl);
fast_reg_page_failure:
        kfree(desc);
err:
        iser_free_frwr_pool(ib_conn);
        return ret;
}

/**
 * iser_free_frwr_pool - releases the pool of fast_reg descriptors
 */
void iser_free_frwr_pool(struct iser_conn *ib_conn)
{
        struct fast_reg_descriptor *desc, *tmp;
        int i = 0;

        if (list_empty(&ib_conn->fastreg.frwr.pool))
                return;

        iser_info("freeing conn %p frwr pool\n", ib_conn);

        list_for_each_entry_safe(desc, tmp, &ib_conn->fastreg.frwr.pool, list) {
                list_del(&desc->list);
                ib_free_fast_reg_page_list(desc->data_frpl);
                ib_dereg_mr(desc->data_mr);
                kfree(desc);
                ++i;
        }

        if (i < ib_conn->fastreg.frwr.pool_size)
                iser_warn("pool still has %d regions registered\n",
                          ib_conn->fastreg.frwr.pool_size - i);
}

/**
 * iser_create_ib_conn_res - Queue-Pair (QP)
 *
 * returns 0 on success, -1 on failure
 */
static int iser_create_ib_conn_res(struct iser_conn *ib_conn)
{
        struct iser_device      *device;
        struct ib_qp_init_attr  init_attr;
        int                     ret = -ENOMEM;
        int index, min_index = 0;

        BUG_ON(ib_conn->device == NULL);

        device = ib_conn->device;

        memset(&init_attr, 0, sizeof init_attr);

        mutex_lock(&ig.connlist_mutex);
        /* select the CQ with the minimal number of usages */
        for (index = 0; index < device->cqs_used; index++)
                if (device->cq_active_qps[index] <
                    device->cq_active_qps[min_index])
                        min_index = index;
        device->cq_active_qps[min_index]++;
        mutex_unlock(&ig.connlist_mutex);
        iser_info("cq index %d used for ib_conn %p\n", min_index, ib_conn);

        init_attr.event_handler = iser_qp_event_callback;
        init_attr.qp_context    = (void *)ib_conn;
        init_attr.send_cq       = device->tx_cq[min_index];
        init_attr.recv_cq       = device->rx_cq[min_index];
        init_attr.cap.max_send_wr  = ISER_QP_MAX_REQ_DTOS;
        init_attr.cap.max_recv_wr  = ISER_QP_MAX_RECV_DTOS;
        init_attr.cap.max_send_sge = 2;
        init_attr.cap.max_recv_sge = 1;
        init_attr.sq_sig_type   = IB_SIGNAL_REQ_WR;
        init_attr.qp_type       = IB_QPT_RC;

        ret = rdma_create_qp(ib_conn->cma_id, device->pd, &init_attr);
        if (ret)
                goto out_err;

        ib_conn->qp = ib_conn->cma_id->qp;
        iser_info("setting conn %p cma_id %p qp %p\n",
                  ib_conn, ib_conn->cma_id,
                  ib_conn->cma_id->qp);
        return ret;

out_err:
        iser_err("unable to alloc mem or create resource, err %d\n", ret);
        return ret;
}

/**
 * releases the QP objects, returns 0 on success,
 * -1 on failure
 */
static int iser_free_ib_conn_res(struct iser_conn *ib_conn)
{
        int cq_index;
        BUG_ON(ib_conn == NULL);

        iser_info("freeing conn %p cma_id %p qp %p\n",
                  ib_conn, ib_conn->cma_id,
                  ib_conn->qp);

        /* qp is created only once both addr & route are resolved */

        if (ib_conn->qp != NULL) {
                cq_index = ((struct iser_cq_desc *)ib_conn->qp->recv_cq->cq_context)->cq_index;
                ib_conn->device->cq_active_qps[cq_index]--;

                rdma_destroy_qp(ib_conn->cma_id);
        }

        ib_conn->qp       = NULL;

        return 0;
}

/**
 * based on the resolved device node GUID see if there already allocated
 * device for this device. If there's no such, create one.
 */
static
struct iser_device *iser_device_find_by_ib_device(struct rdma_cm_id *cma_id)
{
        struct iser_device *device;

        mutex_lock(&ig.device_list_mutex);

        list_for_each_entry(device, &ig.device_list, ig_list)
                /* find if there's a match using the node GUID */
                if (device->ib_device->node_guid == cma_id->device->node_guid)
                        goto inc_refcnt;

        device = kzalloc(sizeof *device, GFP_KERNEL);
        if (device == NULL)
                goto out;

        /* assign this device to the device */
        device->ib_device = cma_id->device;
        /* init the device and link it into ig device list */
        if (iser_create_device_ib_res(device)) {
                kfree(device);
                device = NULL;
                goto out;
        }
        list_add(&device->ig_list, &ig.device_list);

inc_refcnt:
        device->refcount++;
out:
        mutex_unlock(&ig.device_list_mutex);
        return device;
}

/* if there's no demand for this device, release it */
static void iser_device_try_release(struct iser_device *device)
{
        mutex_lock(&ig.device_list_mutex);
        device->refcount--;
        iser_info("device %p refcount %d\n", device, device->refcount);
        if (!device->refcount) {
                iser_free_device_ib_res(device);
                list_del(&device->ig_list);
                kfree(device);
        }
        mutex_unlock(&ig.device_list_mutex);
}

static int iser_conn_state_comp_exch(struct iser_conn *ib_conn,
                                     enum iser_ib_conn_state comp,
                                     enum iser_ib_conn_state exch)
{
        int ret;

        spin_lock_bh(&ib_conn->lock);
        if ((ret = (ib_conn->state == comp)))
                ib_conn->state = exch;
        spin_unlock_bh(&ib_conn->lock);
        return ret;
}

/**
 * Frees all conn objects and deallocs conn descriptor
 */
static void iser_conn_release(struct iser_conn *ib_conn, int can_destroy_id)
{
        struct iser_device  *device = ib_conn->device;

        BUG_ON(ib_conn->state != ISER_CONN_DOWN);

        mutex_lock(&ig.connlist_mutex);
        list_del(&ib_conn->conn_list);
        mutex_unlock(&ig.connlist_mutex);
        iser_free_rx_descriptors(ib_conn);
        iser_free_ib_conn_res(ib_conn);
        ib_conn->device = NULL;
        /* on EVENT_ADDR_ERROR there's no device yet for this conn */
        if (device != NULL)
                iser_device_try_release(device);
        /* if cma handler context, the caller actually destroy the id */
        if (ib_conn->cma_id != NULL && can_destroy_id) {
                rdma_destroy_id(ib_conn->cma_id);
                ib_conn->cma_id = NULL;
        }
        iscsi_destroy_endpoint(ib_conn->ep);
}

void iser_conn_get(struct iser_conn *ib_conn)
{
        atomic_inc(&ib_conn->refcount);
}

int iser_conn_put(struct iser_conn *ib_conn, int can_destroy_id)
{
        if (atomic_dec_and_test(&ib_conn->refcount)) {
                iser_conn_release(ib_conn, can_destroy_id);
                return 1;
        }
        return 0;
}

/**
 * triggers start of the disconnect procedures and wait for them to be done
 */
void iser_conn_terminate(struct iser_conn *ib_conn)
{
        int err = 0;

        /* change the ib conn state only if the conn is UP, however always call
         * rdma_disconnect since this is the only way to cause the CMA to change
         * the QP state to ERROR
         */

        iser_conn_state_comp_exch(ib_conn, ISER_CONN_UP, ISER_CONN_TERMINATING);
        err = rdma_disconnect(ib_conn->cma_id);
        if (err)
                iser_err("Failed to disconnect, conn: 0x%p err %d\n",
                         ib_conn,err);

        wait_event_interruptible(ib_conn->wait,
                                 ib_conn->state == ISER_CONN_DOWN);

        iser_conn_put(ib_conn, 1); /* deref ib conn deallocate */
}

static int iser_connect_error(struct rdma_cm_id *cma_id)
{
        struct iser_conn *ib_conn;
        ib_conn = (struct iser_conn *)cma_id->context;

        ib_conn->state = ISER_CONN_DOWN;
        wake_up_interruptible(&ib_conn->wait);
        return iser_conn_put(ib_conn, 0); /* deref ib conn's cma id */
}

static int iser_addr_handler(struct rdma_cm_id *cma_id)
{
        struct iser_device *device;
        struct iser_conn   *ib_conn;
        int    ret;

        device = iser_device_find_by_ib_device(cma_id);
        if (!device) {
                iser_err("device lookup/creation failed\n");
                return iser_connect_error(cma_id);
        }

        ib_conn = (struct iser_conn *)cma_id->context;
        ib_conn->device = device;

        ret = rdma_resolve_route(cma_id, 1000);
        if (ret) {
                iser_err("resolve route failed: %d\n", ret);
                return iser_connect_error(cma_id);
        }

        return 0;
}

static int iser_route_handler(struct rdma_cm_id *cma_id)
{
        struct rdma_conn_param conn_param;
        int    ret;
        struct iser_cm_hdr req_hdr;

        ret = iser_create_ib_conn_res((struct iser_conn *)cma_id->context);
        if (ret)
                goto failure;

        memset(&conn_param, 0, sizeof conn_param);
        conn_param.responder_resources = 4;
        conn_param.initiator_depth     = 1;
        conn_param.retry_count         = 7;
        conn_param.rnr_retry_count     = 6;

        memset(&req_hdr, 0, sizeof(req_hdr));
        req_hdr.flags = (ISER_ZBVA_NOT_SUPPORTED |
                        ISER_SEND_W_INV_NOT_SUPPORTED);
        conn_param.private_data         = (void *)&req_hdr;
        conn_param.private_data_len     = sizeof(struct iser_cm_hdr);

        ret = rdma_connect(cma_id, &conn_param);
        if (ret) {
                iser_err("failure connecting: %d\n", ret);
                goto failure;
        }

        return 0;
failure:
        return iser_connect_error(cma_id);
}

static void iser_connected_handler(struct rdma_cm_id *cma_id)
{
        struct iser_conn *ib_conn;

        ib_conn = (struct iser_conn *)cma_id->context;
        ib_conn->state = ISER_CONN_UP;
        wake_up_interruptible(&ib_conn->wait);
}

static int iser_disconnected_handler(struct rdma_cm_id *cma_id)
{
        struct iser_conn *ib_conn;
        int ret;

        ib_conn = (struct iser_conn *)cma_id->context;

        /* getting here when the state is UP means that the conn is being *
         * terminated asynchronously from the iSCSI layer's perspective.  */
        if (iser_conn_state_comp_exch(ib_conn, ISER_CONN_UP,
                                        ISER_CONN_TERMINATING)){
                if (ib_conn->iser_conn)
                        iscsi_conn_failure(ib_conn->iser_conn->iscsi_conn,
                                           ISCSI_ERR_CONN_FAILED);
                else
                        iser_err("iscsi_iser connection isn't bound\n");
        }

        /* Complete the termination process if no posts are pending */
        if (ib_conn->post_recv_buf_count == 0 &&
            (atomic_read(&ib_conn->post_send_buf_count) == 0)) {
                ib_conn->state = ISER_CONN_DOWN;
                wake_up_interruptible(&ib_conn->wait);
        }

        ret = iser_conn_put(ib_conn, 0); /* deref ib conn's cma id */
        return ret;
}

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

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

        switch (event->event) {
        case RDMA_CM_EVENT_ADDR_RESOLVED:
                ret = iser_addr_handler(cma_id);
                break;
        case RDMA_CM_EVENT_ROUTE_RESOLVED:
                ret = iser_route_handler(cma_id);
                break;
        case RDMA_CM_EVENT_ESTABLISHED:
                iser_connected_handler(cma_id);
                break;
        case RDMA_CM_EVENT_ADDR_ERROR:
        case RDMA_CM_EVENT_ROUTE_ERROR:
        case RDMA_CM_EVENT_CONNECT_ERROR:
        case RDMA_CM_EVENT_UNREACHABLE:
        case RDMA_CM_EVENT_REJECTED:
                ret = iser_connect_error(cma_id);
                break;
        case RDMA_CM_EVENT_DISCONNECTED:
        case RDMA_CM_EVENT_DEVICE_REMOVAL:
        case RDMA_CM_EVENT_ADDR_CHANGE:
                ret = iser_disconnected_handler(cma_id);
                break;
        default:
                iser_err("Unexpected RDMA CM event (%d)\n", event->event);
                break;
        }
        return ret;
}

void iser_conn_init(struct iser_conn *ib_conn)
{
        ib_conn->state = ISER_CONN_INIT;
        init_waitqueue_head(&ib_conn->wait);
        ib_conn->post_recv_buf_count = 0;
        atomic_set(&ib_conn->post_send_buf_count, 0);
        atomic_set(&ib_conn->refcount, 1); /* ref ib conn allocation */
        INIT_LIST_HEAD(&ib_conn->conn_list);
        spin_lock_init(&ib_conn->lock);
}

 /**
 * starts the process of connecting to the target
 * sleeps until the connection is established or rejected
 */
int iser_connect(struct iser_conn   *ib_conn,
                 struct sockaddr_in *src_addr,
                 struct sockaddr_in *dst_addr,
                 int                 non_blocking)
{
        struct sockaddr *src, *dst;
        int err = 0;

        sprintf(ib_conn->name, "%pI4:%d",
                &dst_addr->sin_addr.s_addr, dst_addr->sin_port);

        /* the device is known only --after-- address resolution */
        ib_conn->device = NULL;

        iser_info("connecting to: %pI4, port 0x%x\n",
                  &dst_addr->sin_addr, dst_addr->sin_port);

        ib_conn->state = ISER_CONN_PENDING;

        iser_conn_get(ib_conn); /* ref ib conn's cma id */
        ib_conn->cma_id = rdma_create_id(iser_cma_handler,
                                             (void *)ib_conn,
                                             RDMA_PS_TCP, IB_QPT_RC);
        if (IS_ERR(ib_conn->cma_id)) {
                err = PTR_ERR(ib_conn->cma_id);
                iser_err("rdma_create_id failed: %d\n", err);
                goto id_failure;
        }

        src = (struct sockaddr *)src_addr;
        dst = (struct sockaddr *)dst_addr;
        err = rdma_resolve_addr(ib_conn->cma_id, src, dst, 1000);
        if (err) {
                iser_err("rdma_resolve_addr failed: %d\n", err);
                goto addr_failure;
        }

        if (!non_blocking) {
                wait_event_interruptible(ib_conn->wait,
                                         (ib_conn->state != ISER_CONN_PENDING));

                if (ib_conn->state != ISER_CONN_UP) {
                        err =  -EIO;
                        goto connect_failure;
                }
        }

        mutex_lock(&ig.connlist_mutex);
        list_add(&ib_conn->conn_list, &ig.connlist);
        mutex_unlock(&ig.connlist_mutex);
        return 0;

id_failure:
        ib_conn->cma_id = NULL;
addr_failure:
        ib_conn->state = ISER_CONN_DOWN;
        iser_conn_put(ib_conn, 1); /* deref ib conn's cma id */
connect_failure:
        iser_conn_put(ib_conn, 1); /* deref ib conn deallocate */
        return err;
}

/**
 * iser_reg_page_vec - Register physical memory
 *
 * returns: 0 on success, errno code on failure
 */
int iser_reg_page_vec(struct iser_conn     *ib_conn,
                      struct iser_page_vec *page_vec,
                      struct iser_mem_reg  *mem_reg)
{
        struct ib_pool_fmr *mem;
        u64                io_addr;
        u64                *page_list;
        int                status;

        page_list = page_vec->pages;
        io_addr   = page_list[0];

        mem  = ib_fmr_pool_map_phys(ib_conn->fastreg.fmr.pool,
                                    page_list,
                                    page_vec->length,
                                    io_addr);

        if (IS_ERR(mem)) {
                status = (int)PTR_ERR(mem);
                iser_err("ib_fmr_pool_map_phys failed: %d\n", status);
                return status;
        }

        mem_reg->lkey  = mem->fmr->lkey;
        mem_reg->rkey  = mem->fmr->rkey;
        mem_reg->len   = page_vec->length * SIZE_4K;
        mem_reg->va    = io_addr;
        mem_reg->is_mr = 1;
        mem_reg->mem_h = (void *)mem;

        mem_reg->va   += page_vec->offset;
        mem_reg->len   = page_vec->data_size;

        iser_dbg("PHYSICAL Mem.register, [PHYS p_array: 0x%p, sz: %d, "
                 "entry[0]: (0x%08lx,%ld)] -> "
                 "[lkey: 0x%08X mem_h: 0x%p va: 0x%08lX sz: %ld]\n",
                 page_vec, page_vec->length,
                 (unsigned long)page_vec->pages[0],
                 (unsigned long)page_vec->data_size,
                 (unsigned int)mem_reg->lkey, mem_reg->mem_h,
                 (unsigned long)mem_reg->va, (unsigned long)mem_reg->len);
        return 0;
}

/**
 * Unregister (previosuly registered using FMR) memory.
 * If memory is non-FMR does nothing.
 */
void iser_unreg_mem_fmr(struct iscsi_iser_task *iser_task,
                        enum iser_data_dir cmd_dir)
{
        struct iser_mem_reg *reg = &iser_task->rdma_regd[cmd_dir].reg;
        int ret;

        if (!reg->is_mr)
                return;

        iser_dbg("PHYSICAL Mem.Unregister mem_h %p\n",reg->mem_h);

        ret = ib_fmr_pool_unmap((struct ib_pool_fmr *)reg->mem_h);
        if (ret)
                iser_err("ib_fmr_pool_unmap failed %d\n", ret);

        reg->mem_h = NULL;
}

void iser_unreg_mem_frwr(struct iscsi_iser_task *iser_task,
                         enum iser_data_dir cmd_dir)
{
        struct iser_mem_reg *reg = &iser_task->rdma_regd[cmd_dir].reg;
        struct iser_conn *ib_conn = iser_task->iser_conn->ib_conn;
        struct fast_reg_descriptor *desc = reg->mem_h;

        if (!reg->is_mr)
                return;

        reg->mem_h = NULL;
        reg->is_mr = 0;
        spin_lock_bh(&ib_conn->lock);
        list_add_tail(&desc->list, &ib_conn->fastreg.frwr.pool);
        spin_unlock_bh(&ib_conn->lock);
}

int iser_post_recvl(struct iser_conn *ib_conn)
{
        struct ib_recv_wr rx_wr, *rx_wr_failed;
        struct ib_sge     sge;
        int ib_ret;

        sge.addr   = ib_conn->login_resp_dma;
        sge.length = ISER_RX_LOGIN_SIZE;
        sge.lkey   = ib_conn->device->mr->lkey;

        rx_wr.wr_id   = (unsigned long)ib_conn->login_resp_buf;
        rx_wr.sg_list = &sge;
        rx_wr.num_sge = 1;
        rx_wr.next    = NULL;

        ib_conn->post_recv_buf_count++;
        ib_ret  = ib_post_recv(ib_conn->qp, &rx_wr, &rx_wr_failed);
        if (ib_ret) {
                iser_err("ib_post_recv failed ret=%d\n", ib_ret);
                ib_conn->post_recv_buf_count--;
        }
        return ib_ret;
}

int iser_post_recvm(struct iser_conn *ib_conn, int count)
{
        struct ib_recv_wr *rx_wr, *rx_wr_failed;
        int i, ib_ret;
        unsigned int my_rx_head = ib_conn->rx_desc_head;
        struct iser_rx_desc *rx_desc;

        for (rx_wr = ib_conn->rx_wr, i = 0; i < count; i++, rx_wr++) {
                rx_desc         = &ib_conn->rx_descs[my_rx_head];
                rx_wr->wr_id    = (unsigned long)rx_desc;
                rx_wr->sg_list  = &rx_desc->rx_sg;
                rx_wr->num_sge  = 1;
                rx_wr->next     = rx_wr + 1;
                my_rx_head = (my_rx_head + 1) & ib_conn->qp_max_recv_dtos_mask;
        }

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

        ib_conn->post_recv_buf_count += count;
        ib_ret  = ib_post_recv(ib_conn->qp, ib_conn->rx_wr, &rx_wr_failed);
        if (ib_ret) {
                iser_err("ib_post_recv failed ret=%d\n", ib_ret);
                ib_conn->post_recv_buf_count -= count;
        } else
                ib_conn->rx_desc_head = my_rx_head;
        return ib_ret;
}


/**
 * iser_start_send - Initiate a Send DTO operation
 *
 * returns 0 on success, -1 on failure
 */
int iser_post_send(struct iser_conn *ib_conn, struct iser_tx_desc *tx_desc)
{
        int               ib_ret;
        struct ib_send_wr send_wr, *send_wr_failed;

        ib_dma_sync_single_for_device(ib_conn->device->ib_device,
                tx_desc->dma_addr, ISER_HEADERS_LEN, DMA_TO_DEVICE);

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

        atomic_inc(&ib_conn->post_send_buf_count);

        ib_ret = ib_post_send(ib_conn->qp, &send_wr, &send_wr_failed);
        if (ib_ret) {
                iser_err("ib_post_send failed, ret:%d\n", ib_ret);
                atomic_dec(&ib_conn->post_send_buf_count);
        }
        return ib_ret;
}

static void iser_handle_comp_error(struct iser_tx_desc *desc,
                                struct iser_conn *ib_conn)
{
        if (desc && desc->type == ISCSI_TX_DATAOUT)
                kmem_cache_free(ig.desc_cache, desc);

        if (ib_conn->post_recv_buf_count == 0 &&
            atomic_read(&ib_conn->post_send_buf_count) == 0) {
                /* getting here when the state is UP means that the conn is *
                 * being terminated asynchronously from the iSCSI layer's   *
                 * perspective.                                             */
                if (iser_conn_state_comp_exch(ib_conn, ISER_CONN_UP,
                    ISER_CONN_TERMINATING))
                        iscsi_conn_failure(ib_conn->iser_conn->iscsi_conn,
                                           ISCSI_ERR_CONN_FAILED);

                /* no more non completed posts to the QP, complete the
                 * termination process w.o worrying on disconnect event */
                ib_conn->state = ISER_CONN_DOWN;
                wake_up_interruptible(&ib_conn->wait);
        }
}

static int iser_drain_tx_cq(struct iser_device  *device, int cq_index)
{
        struct ib_cq  *cq = device->tx_cq[cq_index];
        struct ib_wc  wc;
        struct iser_tx_desc *tx_desc;
        struct iser_conn *ib_conn;
        int completed_tx = 0;

        while (ib_poll_cq(cq, 1, &wc) == 1) {
                tx_desc = (struct iser_tx_desc *) (unsigned long) wc.wr_id;
                ib_conn = wc.qp->qp_context;
                if (wc.status == IB_WC_SUCCESS) {
                        if (wc.opcode == IB_WC_SEND)
                                iser_snd_completion(tx_desc, ib_conn);
                        else if (wc.opcode == IB_WC_LOCAL_INV ||
                                 wc.opcode == IB_WC_FAST_REG_MR) {
                                atomic_dec(&ib_conn->post_send_buf_count);
                                continue;
                        } else

                                iser_err("expected opcode %d got %d\n",
                                        IB_WC_SEND, wc.opcode);
                } else {
                        iser_err("tx id %llx status %d vend_err %x\n",
                                wc.wr_id, wc.status, wc.vendor_err);
                        atomic_dec(&ib_conn->post_send_buf_count);
                        iser_handle_comp_error(tx_desc, ib_conn);
                }
                completed_tx++;
        }
        return completed_tx;
}


static void iser_cq_tasklet_fn(unsigned long data)
{
        struct iser_cq_desc *cq_desc = (struct iser_cq_desc *)data;
        struct iser_device  *device = cq_desc->device;
        int cq_index = cq_desc->cq_index;
        struct ib_cq         *cq = device->rx_cq[cq_index];
         struct ib_wc        wc;
         struct iser_rx_desc *desc;
         unsigned long       xfer_len;
        struct iser_conn *ib_conn;
        int completed_tx, completed_rx;
        completed_tx = completed_rx = 0;

        while (ib_poll_cq(cq, 1, &wc) == 1) {
                desc     = (struct iser_rx_desc *) (unsigned long) wc.wr_id;
                BUG_ON(desc == NULL);
                ib_conn = wc.qp->qp_context;
                if (wc.status == IB_WC_SUCCESS) {
                        if (wc.opcode == IB_WC_RECV) {
                                xfer_len = (unsigned long)wc.byte_len;
                                iser_rcv_completion(desc, xfer_len, ib_conn);
                        } else
                                iser_err("expected opcode %d got %d\n",
                                        IB_WC_RECV, wc.opcode);
                } else {
                        if (wc.status != IB_WC_WR_FLUSH_ERR)
                                iser_err("rx id %llx status %d vend_err %x\n",
                                        wc.wr_id, wc.status, wc.vendor_err);
                        ib_conn->post_recv_buf_count--;
                        iser_handle_comp_error(NULL, ib_conn);
                }
                completed_rx++;
                if (!(completed_rx & 63))
                        completed_tx += iser_drain_tx_cq(device, cq_index);
        }
        /* #warning "it is assumed here that arming CQ only once its empty" *
         * " would not cause interrupts to be missed"                       */
        ib_req_notify_cq(cq, IB_CQ_NEXT_COMP);

        completed_tx += iser_drain_tx_cq(device, cq_index);
        iser_dbg("got %d rx %d tx completions\n", completed_rx, completed_tx);
}

static void iser_cq_callback(struct ib_cq *cq, void *cq_context)
{
        struct iser_cq_desc *cq_desc = (struct iser_cq_desc *)cq_context;
        struct iser_device  *device = cq_desc->device;
        int cq_index = cq_desc->cq_index;

        tasklet_schedule(&device->cq_tasklet[cq_index]);
}