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    Subject[PATCH 4/6] iSER RDMA CM (CMA) and IB verbs interaction
    This file contains the low level interaction with the RDMA CM 
    and the IB verbs, where iSER is consumer of both.

    Signed-off-by: Or Gerlitz <ogerlitz@voltaire.com>

    --- /usr/src/linux-2.6.17-rc3/drivers/infiniband/ulp/iser-x/iser_verbs.c 1970-01-01 02:00:00.000000000 +0200
    +++ /usr/src/linux-2.6.17-rc3/drivers/infiniband/ulp/iser/iser_verbs.c 2006-05-10 15:32:01.000000000 +0300
    @@ -0,0 +1,827 @@
    +/*
    + * Copyright (c) 2004, 2005, 2006 Voltaire, Inc. All rights reserved.
    + * Copyright (c) 2005, 2006 Cisco Systems. 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.
    + *
    + * $Id: iser_verbs.c 7051 2006-05-10 12:29:11Z ogerlitz $
    + */
    +#include <asm/io.h>
    +#include <linux/kernel.h>
    +#include <linux/module.h>
    +#include <linux/smp_lock.h>
    +#include <linux/delay.h>
    +#include <linux/version.h>
    +
    +#include "iscsi_iser.h"
    +
    +#define ISCSI_ISER_MAX_CONN 8
    +#define ISER_MAX_CQ_LEN ((ISER_QP_MAX_RECV_DTOS + \
    + 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_comp_error_worker(void *data);
    +
    +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);
    +}
    +
    +/**
    + * 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)
    +{
    + device->pd = ib_alloc_pd(device->ib_device);
    + if (IS_ERR(device->pd))
    + goto pd_err;
    +
    + device->cq = ib_create_cq(device->ib_device,
    + iser_cq_callback,
    + iser_cq_event_callback,
    + (void *)device,
    + ISER_MAX_CQ_LEN);
    + if (IS_ERR(device->cq))
    + goto cq_err;
    +
    + if (ib_req_notify_cq(device->cq, IB_CQ_NEXT_COMP))
    + goto cq_arm_err;
    +
    + tasklet_init(&device->cq_tasklet,
    + iser_cq_tasklet_fn,
    + (unsigned long)device);
    +
    + device->mr = ib_get_dma_mr(device->pd,
    + IB_ACCESS_LOCAL_WRITE);
    + if (IS_ERR(device->mr))
    + goto dma_mr_err;
    +
    + return 0;
    +
    +dma_mr_err:
    + tasklet_kill(&device->cq_tasklet);
    +cq_arm_err:
    + ib_destroy_cq(device->cq);
    +cq_err:
    + ib_dealloc_pd(device->pd);
    +pd_err:
    + iser_err("failed to allocate an IB resource\n");
    + return -1;
    +}
    +
    +/**
    + * iser_free_device_ib_res - destory/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)
    +{
    + BUG_ON(device->mr == NULL);
    +
    + tasklet_kill(&device->cq_tasklet);
    +
    + (void)ib_dereg_mr(device->mr);
    + (void)ib_destroy_cq(device->cq);
    + (void)ib_dealloc_pd(device->pd);
    +
    + device->mr = NULL;
    + device->cq = NULL;
    + device->pd = NULL;
    +}
    +
    +/**
    + * iser_create_ib_conn_res - Creates FMR pool and 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;
    + struct ib_fmr_pool_param params;
    +
    + BUG_ON(ib_conn->device == NULL);
    +
    + device = ib_conn->device;
    +
    + ib_conn->page_vec = kmalloc(sizeof(struct iser_page_vec) +
    + (sizeof(u64) * (ISCSI_ISER_SG_TABLESIZE +1)),
    + GFP_KERNEL);
    + if (!ib_conn->page_vec) {
    + ret = -ENOMEM;
    + goto alloc_err;
    + }
    + ib_conn->page_vec->pages = (u64 *) (ib_conn->page_vec + 1);
    +
    + params.page_shift = PAGE_SHIFT;
    + /* 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 = ISCSI_XMIT_CMDS_MAX * 2;
    + params.dirty_watermark = ISCSI_XMIT_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->fmr_pool = ib_create_fmr_pool(device->pd, &params);
    + if (IS_ERR(ib_conn->fmr_pool)) {
    + ret = PTR_ERR(ib_conn->fmr_pool);
    + goto fmr_pool_err;
    + }
    +
    + memset(&init_attr, 0, sizeof init_attr);
    +
    + init_attr.event_handler = iser_qp_event_callback;
    + init_attr.qp_context = (void *)ib_conn;
    + init_attr.send_cq = device->cq;
    + init_attr.recv_cq = device->cq;
    + 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 = MAX_REGD_BUF_VECTOR_LEN;
    + init_attr.cap.max_recv_sge = 2;
    + 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 qp_err;
    +
    + ib_conn->qp = ib_conn->cma_id->qp;
    + iser_err("setting conn %p cma_id %p: fmr_pool %p qp %p\n",
    + ib_conn, ib_conn->cma_id,
    + ib_conn->fmr_pool, ib_conn->cma_id->qp);
    + return ret;
    +
    +qp_err:
    + (void)ib_destroy_fmr_pool(ib_conn->fmr_pool);
    +fmr_pool_err:
    + kfree(ib_conn->page_vec);
    +alloc_err:
    + iser_err("unable to alloc mem or create resource, err %d\n", ret);
    + return ret;
    +}
    +
    +/**
    + * releases the FMR pool, QP and CMA ID objects, returns 0 on success,
    + * -1 on failure
    + */
    +static int iser_free_ib_conn_res(struct iser_conn *ib_conn)
    +{
    + BUG_ON(ib_conn == NULL);
    +
    + iser_err("freeing conn %p cma_id %p fmr pool %p qp %p\n",
    + ib_conn, ib_conn->cma_id,
    + ib_conn->fmr_pool, ib_conn->qp);
    +
    + /* qp is created only once both addr & route are resolved */
    + if (ib_conn->fmr_pool != NULL)
    + ib_destroy_fmr_pool(ib_conn->fmr_pool);
    +
    + if (ib_conn->qp != NULL)
    + rdma_destroy_qp(ib_conn->cma_id);
    +
    + if (ib_conn->cma_id != NULL)
    + rdma_destroy_id(ib_conn->cma_id);
    +
    + ib_conn->fmr_pool = NULL;
    + ib_conn->qp = NULL;
    + ib_conn->cma_id = NULL;
    + kfree(ib_conn->page_vec);
    +
    + 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 list_head *p_list;
    + struct iser_device *device = NULL;
    +
    + mutex_lock(&ig.device_list_mutex);
    +
    + p_list = ig.device_list.next;
    + while (p_list != &ig.device_list) {
    + device = list_entry(p_list, struct iser_device, ig_list);
    + /* find if there's a match using the node GUID */
    + if (device->ib_device->node_guid == cma_id->device->node_guid)
    + break;
    + }
    +
    + if (device == NULL) {
    + 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);
    + }
    +out:
    + BUG_ON(device == NULL);
    + device->refcount++;
    + 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_err("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);
    +}
    +
    +int iser_conn_state_comp(struct iser_conn *ib_conn,
    + enum iser_ib_conn_state comp)
    +{
    + int ret;
    +
    + spin_lock_bh(&ib_conn->lock);
    + ret = (ib_conn->state == comp);
    + spin_unlock_bh(&ib_conn->lock);
    + return ret;
    +}
    +
    +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;
    +}
    +
    +/**
    + * 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_release(ib_conn);
    +}
    +
    +static void 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);
    +}
    +
    +static void 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);
    + 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);
    + iser_connect_error(cma_id);
    + }
    + return;
    +}
    +
    +static void iser_route_handler(struct rdma_cm_id *cma_id)
    +{
    + struct rdma_conn_param conn_param;
    + int ret;
    +
    + ret = iser_create_ib_conn_res((struct iser_conn *)cma_id->context);
    + if (ret)
    + goto failure;
    +
    + iser_dbg("path.mtu is %d setting it to %d\n",
    + cma_id->route.path_rec->mtu, IB_MTU_1024);
    +
    + /* we must set the MTU to 1024 as this is what the target is assuming */
    + if (cma_id->route.path_rec->mtu > IB_MTU_1024)
    + cma_id->route.path_rec->mtu = IB_MTU_1024;
    +
    + 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;
    +
    + ret = rdma_connect(cma_id, &conn_param);
    + if (ret) {
    + iser_err("failure connecting: %d\n", ret);
    + goto failure;
    + }
    +
    + return;
    +failure:
    + 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 void iser_disconnected_handler(struct rdma_cm_id *cma_id)
    +{
    + struct iser_conn *ib_conn;
    +
    + ib_conn = (struct iser_conn *)cma_id->context;
    + ib_conn->disc_evt_flag = 1;
    +
    + /* 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);
    +
    + /* Complete the termination process if no posts are pending */
    + if ((atomic_read(&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);
    + }
    +}
    +
    +static int iser_cma_handler(struct rdma_cm_id *cma_id, struct rdma_cm_event *event)
    +{
    + int ret = 0;
    +
    + iser_err("event %d conn %p id %p\n",event->event,cma_id->context,cma_id);
    +
    + switch (event->event) {
    + case RDMA_CM_EVENT_ADDR_RESOLVED:
    + iser_addr_handler(cma_id);
    + break;
    + case RDMA_CM_EVENT_ROUTE_RESOLVED:
    + 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:
    + iser_err("event: %d, error: %d\n", event->event, event->status);
    + iser_connect_error(cma_id);
    + break;
    + case RDMA_CM_EVENT_DISCONNECTED:
    + iser_disconnected_handler(cma_id);
    + break;
    + case RDMA_CM_EVENT_DEVICE_REMOVAL:
    + BUG();
    + break;
    + case RDMA_CM_EVENT_CONNECT_RESPONSE:
    + BUG();
    + break;
    + case RDMA_CM_EVENT_CONNECT_REQUEST:
    + default:
    + break;
    + }
    + return ret;
    +}
    +
    +int iser_conn_init(struct iser_conn **ibconn)
    +{
    + struct iser_conn *ib_conn;
    +
    + ib_conn = kzalloc(sizeof *ib_conn, GFP_KERNEL);
    + if (!ib_conn) {
    + iser_err("can't alloc memory for struct iser_conn\n");
    + return -ENOMEM;
    + }
    + ib_conn->state = ISER_CONN_INIT;
    + init_waitqueue_head(&ib_conn->wait);
    + atomic_set(&ib_conn->post_recv_buf_count, 0);
    + atomic_set(&ib_conn->post_send_buf_count, 0);
    + INIT_WORK(&ib_conn->comperror_work, iser_comp_error_worker,
    + ib_conn);
    + INIT_LIST_HEAD(&ib_conn->conn_list);
    + spin_lock_init(&ib_conn->lock);
    +
    + *ibconn = ib_conn;
    + return 0;
    +}
    +
    + /**
    + * starts the process of connecting to the target
    + * sleeps untill 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,"%d.%d.%d.%d:%d",
    + NIPQUAD(dst_addr->sin_addr.s_addr), dst_addr->sin_port);
    +
    + /* the device is known only --after-- address resolution */
    + ib_conn->device = NULL;
    +
    + iser_err("connecting to: %d.%d.%d.%d, port 0x%x\n",
    + NIPQUAD(dst_addr->sin_addr), dst_addr->sin_port);
    +
    + ib_conn->state = ISER_CONN_PENDING;
    +
    + ib_conn->cma_id = rdma_create_id(iser_cma_handler,
    + (void *)ib_conn,
    + RDMA_PS_TCP);
    + 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;
    +connect_failure:
    + iser_conn_release(ib_conn);
    + return err;
    +}
    +
    +/**
    + * Frees all conn objects and deallocs conn descriptor
    + */
    +void iser_conn_release(struct iser_conn *ib_conn)
    +{
    + 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_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);
    + kfree(ib_conn);
    +}
    +
    +
    +/**
    + * 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->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 * PAGE_SIZE;
    + mem_reg->va = io_addr;
    + 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) memory.
    + */
    +void iser_unreg_mem(struct iser_mem_reg *reg)
    +{
    + int ret;
    +
    + 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;
    +}
    +
    +/**
    + * iser_dto_to_iov - builds IOV from a dto descriptor
    + */
    +static void iser_dto_to_iov(struct iser_dto *dto, struct ib_sge *iov, int iov_len)
    +{
    + int i;
    + struct ib_sge *sge;
    + struct iser_regd_buf *regd_buf;
    +
    + if (dto->regd_vector_len > iov_len) {
    + iser_err("iov size %d too small for posting dto of len %d\n",
    + iov_len, dto->regd_vector_len);
    + BUG();
    + }
    +
    + for (i = 0; i < dto->regd_vector_len; i++) {
    + sge = &iov[i];
    + regd_buf = dto->regd[i];
    +
    + sge->addr = regd_buf->reg.va;
    + sge->length = regd_buf->reg.len;
    + sge->lkey = regd_buf->reg.lkey;
    +
    + if (dto->used_sz[i] > 0) /* Adjust size */
    + sge->length = dto->used_sz[i];
    +
    + /* offset and length should not exceed the regd buf length */
    + if (sge->length + dto->offset[i] > regd_buf->reg.len) {
    + iser_err("Used len:%ld + offset:%d, exceed reg.buf.len:"
    + "%ld in dto:0x%p [%d], va:0x%08lX\n",
    + (unsigned long)sge->length, dto->offset[i],
    + (unsigned long)regd_buf->reg.len, dto, i,
    + (unsigned long)sge->addr);
    + BUG();
    + }
    +
    + sge->addr += dto->offset[i]; /* Adjust offset */
    + }
    +}
    +
    +/**
    + * iser_post_recv - Posts a receive buffer.
    + *
    + * returns 0 on success, -1 on failure
    + */
    +int iser_post_recv(struct iser_desc *rx_desc)
    +{
    + int ib_ret, ret_val = 0;
    + struct ib_recv_wr recv_wr, *recv_wr_failed;
    + struct ib_sge iov[2];
    + struct iser_conn *ib_conn;
    + struct iser_dto *recv_dto = &rx_desc->dto;
    +
    + /* Retrieve conn */
    + ib_conn = recv_dto->conn->ib_conn;
    +
    + iser_dto_to_iov(recv_dto, iov, 2);
    +
    + recv_wr.next = NULL;
    + recv_wr.sg_list = iov;
    + recv_wr.num_sge = recv_dto->regd_vector_len;
    + recv_wr.wr_id = (unsigned long)rx_desc;
    +
    + atomic_inc(&ib_conn->post_recv_buf_count);
    + ib_ret = ib_post_recv(ib_conn->qp, &recv_wr, &recv_wr_failed);
    + if (ib_ret) {
    + iser_err("ib_post_recv failed ret=%d\n", ib_ret);
    + atomic_dec(&ib_conn->post_recv_buf_count);
    + ret_val = -1;
    + }
    +
    + return ret_val;
    +}
    +
    +/**
    + * iser_start_send - Initiate a Send DTO operation
    + *
    + * returns 0 on success, -1 on failure
    + */
    +int iser_post_send(struct iser_desc *tx_desc)
    +{
    + int ib_ret, ret_val = 0;
    + struct ib_send_wr send_wr, *send_wr_failed;
    + struct ib_sge iov[MAX_REGD_BUF_VECTOR_LEN];
    + struct iser_conn *ib_conn;
    + struct iser_dto *dto = &tx_desc->dto;
    +
    + ib_conn = dto->conn->ib_conn;
    +
    + iser_dto_to_iov(dto, iov, MAX_REGD_BUF_VECTOR_LEN);
    +
    + send_wr.next = NULL;
    + send_wr.wr_id = (unsigned long)tx_desc;
    + send_wr.sg_list = iov;
    + send_wr.num_sge = dto->regd_vector_len;
    + send_wr.opcode = IB_WR_SEND;
    + send_wr.send_flags = dto->notify_enable ? IB_SEND_SIGNALED : 0;
    +
    + 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("Failed to start SEND DTO, dto: 0x%p, IOV len: %d\n",
    + dto, dto->regd_vector_len);
    + iser_err("ib_post_send failed, ret:%d\n", ib_ret);
    + atomic_dec(&ib_conn->post_send_buf_count);
    + ret_val = -1;
    + }
    +
    + return ret_val;
    +}
    +
    +static void iser_comp_error_worker(void *data)
    +{
    + struct iser_conn *ib_conn = data;
    +
    + /* 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);
    +
    + /* complete the termination process if disconnect event was delivered *
    + * note there are no more non completed posts to the QP */
    + if (ib_conn->disc_evt_flag) {
    + ib_conn->state = ISER_CONN_DOWN;
    + wake_up_interruptible(&ib_conn->wait);
    + }
    +}
    +
    +static void iser_handle_comp_error(struct iser_desc *desc)
    +{
    + struct iser_dto *dto = &desc->dto;
    + struct iser_conn *ib_conn = dto->conn->ib_conn;
    +
    + iser_dto_buffs_release(dto);
    +
    + if (desc->type == ISCSI_RX) {
    + kfree(desc->data);
    + kmem_cache_free(ig.desc_cache, desc);
    + atomic_dec(&ib_conn->post_recv_buf_count);
    + } else { /* type is TX control/command/dataout */
    + if (desc->type == ISCSI_TX_DATAOUT)
    + kmem_cache_free(ig.desc_cache, desc);
    + atomic_dec(&ib_conn->post_send_buf_count);
    + }
    +
    + if (atomic_read(&ib_conn->post_recv_buf_count) == 0 &&
    + atomic_read(&ib_conn->post_send_buf_count) == 0)
    + schedule_work(&ib_conn->comperror_work);
    +}
    +
    +static void iser_cq_tasklet_fn(unsigned long data)
    +{
    + struct iser_device *device = (struct iser_device *)data;
    + struct ib_cq *cq = device->cq;
    + struct ib_wc wc;
    + struct iser_desc *desc;
    + unsigned long xfer_len;
    +
    + while (ib_poll_cq(cq, 1, &wc) == 1) {
    + desc = (struct iser_desc *) (unsigned long) wc.wr_id;
    + BUG_ON(desc == NULL);
    +
    + if (wc.status == IB_WC_SUCCESS) {
    + if (desc->type == ISCSI_RX) {
    + xfer_len = (unsigned long)wc.byte_len;
    + iser_rcv_completion(desc, xfer_len);
    + } else /* type == ISCSI_TX_CONTROL/SCSI_CMD/DOUT */
    + iser_snd_completion(desc);
    + } else {
    + iser_err("comp w. error op %d status %d\n",desc->type,wc.status);
    + iser_handle_comp_error(desc);
    + }
    + }
    + /* #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);
    +}
    +
    +static void iser_cq_callback(struct ib_cq *cq, void *cq_context)
    +{
    + struct iser_device *device = (struct iser_device *)cq_context;
    +
    + tasklet_schedule(&device->cq_tasklet);
    +}
    -
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