[deliverable/linux.git] / drivers / infiniband / ulp / iser / iser_initiator.c

/*
 * Copyright (c) 2004, 2005, 2006 Voltaire, Inc. 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_initiator.c 6964 2006-05-07 11:11:43Z ogerlitz $
 */
#include <linux/kernel.h>
#include <linux/slab.h>
#include <linux/mm.h>
#include <asm/io.h>
#include <asm/scatterlist.h>
#include <linux/scatterlist.h>
#include <linux/kfifo.h>
#include <scsi/scsi_cmnd.h>
#include <scsi/scsi_host.h>

#include "iscsi_iser.h"

/* Constant PDU lengths calculations */
#define ISER_TOTAL_HEADERS_LEN  (sizeof (struct iser_hdr) + \
                                 sizeof (struct iscsi_hdr))

/* iser_dto_add_regd_buff - increments the reference count for *
 * the registered buffer & adds it to the DTO object           */
static void iser_dto_add_regd_buff(struct iser_dto *dto,
                                   struct iser_regd_buf *regd_buf,
                                   unsigned long use_offset,
                                   unsigned long use_size)
{
        int add_idx;

        atomic_inc(&regd_buf->ref_count);

        add_idx = dto->regd_vector_len;
        dto->regd[add_idx] = regd_buf;
        dto->used_sz[add_idx] = use_size;
        dto->offset[add_idx] = use_offset;

        dto->regd_vector_len++;
}

/* Register user buffer memory and initialize passive rdma
 *  dto descriptor. Total data size is stored in
 *  iser_ctask->data[ISER_DIR_IN].data_len
 */
static int iser_prepare_read_cmd(struct iscsi_cmd_task *ctask,
                                 unsigned int edtl)

{
        struct iscsi_iser_cmd_task *iser_ctask = ctask->dd_data;
        struct iser_regd_buf *regd_buf;
        int err;
        struct iser_hdr *hdr = &iser_ctask->desc.iser_header;
        struct iser_data_buf *buf_in = &iser_ctask->data[ISER_DIR_IN];

        err = iser_dma_map_task_data(iser_ctask,
                                     buf_in,
                                     ISER_DIR_IN,
                                     DMA_FROM_DEVICE);
        if (err)
                return err;

        if (edtl > iser_ctask->data[ISER_DIR_IN].data_len) {
                iser_err("Total data length: %ld, less than EDTL: "
                         "%d, in READ cmd BHS itt: %d, conn: 0x%p\n",
                         iser_ctask->data[ISER_DIR_IN].data_len, edtl,
                         ctask->itt, iser_ctask->iser_conn);
                return -EINVAL;
        }

        err = iser_reg_rdma_mem(iser_ctask,ISER_DIR_IN);
        if (err) {
                iser_err("Failed to set up Data-IN RDMA\n");
                return err;
        }
        regd_buf = &iser_ctask->rdma_regd[ISER_DIR_IN];

        hdr->flags    |= ISER_RSV;
        hdr->read_stag = cpu_to_be32(regd_buf->reg.rkey);
        hdr->read_va   = cpu_to_be64(regd_buf->reg.va);

        iser_dbg("Cmd itt:%d READ tags RKEY:%#.4X VA:%#llX\n",
                 ctask->itt, regd_buf->reg.rkey,
                 (unsigned long long)regd_buf->reg.va);

        return 0;
}

/* Register user buffer memory and initialize passive rdma
 *  dto descriptor. Total data size is stored in
 *  ctask->data[ISER_DIR_OUT].data_len
 */
static int
iser_prepare_write_cmd(struct iscsi_cmd_task *ctask,
                       unsigned int imm_sz,
                       unsigned int unsol_sz,
                       unsigned int edtl)
{
        struct iscsi_iser_cmd_task *iser_ctask = ctask->dd_data;
        struct iser_regd_buf *regd_buf;
        int err;
        struct iser_dto *send_dto = &iser_ctask->desc.dto;
        struct iser_hdr *hdr = &iser_ctask->desc.iser_header;
        struct iser_data_buf *buf_out = &iser_ctask->data[ISER_DIR_OUT];

        err = iser_dma_map_task_data(iser_ctask,
                                     buf_out,
                                     ISER_DIR_OUT,
                                     DMA_TO_DEVICE);
        if (err)
                return err;

        if (edtl > iser_ctask->data[ISER_DIR_OUT].data_len) {
                iser_err("Total data length: %ld, less than EDTL: %d, "
                         "in WRITE cmd BHS itt: %d, conn: 0x%p\n",
                         iser_ctask->data[ISER_DIR_OUT].data_len,
                         edtl, ctask->itt, ctask->conn);
                return -EINVAL;
        }

        err = iser_reg_rdma_mem(iser_ctask,ISER_DIR_OUT);
        if (err != 0) {
                iser_err("Failed to register write cmd RDMA mem\n");
                return err;
        }

        regd_buf = &iser_ctask->rdma_regd[ISER_DIR_OUT];

        if (unsol_sz < edtl) {
                hdr->flags     |= ISER_WSV;
                hdr->write_stag = cpu_to_be32(regd_buf->reg.rkey);
                hdr->write_va   = cpu_to_be64(regd_buf->reg.va + unsol_sz);

                iser_dbg("Cmd itt:%d, WRITE tags, RKEY:%#.4X "
                         "VA:%#llX + unsol:%d\n",
                         ctask->itt, regd_buf->reg.rkey,
                         (unsigned long long)regd_buf->reg.va, unsol_sz);
        }

        if (imm_sz > 0) {
                iser_dbg("Cmd itt:%d, WRITE, adding imm.data sz: %d\n",
                         ctask->itt, imm_sz);
                iser_dto_add_regd_buff(send_dto,
                                       regd_buf,
                                       0,
                                       imm_sz);
        }

        return 0;
}

/**
 * iser_post_receive_control - allocates, initializes and posts receive DTO.
 */
static int iser_post_receive_control(struct iscsi_conn *conn)
{
        struct iscsi_iser_conn *iser_conn = conn->dd_data;
        struct iser_desc     *rx_desc;
        struct iser_regd_buf *regd_hdr;
        struct iser_regd_buf *regd_data;
        struct iser_dto      *recv_dto = NULL;
        struct iser_device  *device = iser_conn->ib_conn->device;
        int rx_data_size, err = 0;

        rx_desc = kmem_cache_alloc(ig.desc_cache, GFP_NOIO);
        if (rx_desc == NULL) {
                iser_err("Failed to alloc desc for post recv\n");
                return -ENOMEM;
        }
        rx_desc->type = ISCSI_RX;

        /* for the login sequence we must support rx of upto 8K; login is done
         * after conn create/bind (connect) and conn stop/bind (reconnect),
         * what's common for both schemes is that the connection is not started
         */
        if (conn->c_stage != ISCSI_CONN_STARTED)
                rx_data_size = ISCSI_DEF_MAX_RECV_SEG_LEN;
        else /* FIXME till user space sets conn->max_recv_dlength correctly */
                rx_data_size = 128;

        rx_desc->data = kmalloc(rx_data_size, GFP_NOIO);
        if (rx_desc->data == NULL) {
                iser_err("Failed to alloc data buf for post recv\n");
                err = -ENOMEM;
                goto post_rx_kmalloc_failure;
        }

        recv_dto = &rx_desc->dto;
        recv_dto->ib_conn = iser_conn->ib_conn;
        recv_dto->regd_vector_len = 0;

        regd_hdr = &rx_desc->hdr_regd_buf;
        memset(regd_hdr, 0, sizeof(struct iser_regd_buf));
        regd_hdr->device  = device;
        regd_hdr->virt_addr  = rx_desc; /* == &rx_desc->iser_header */
        regd_hdr->data_size  = ISER_TOTAL_HEADERS_LEN;

        iser_reg_single(device, regd_hdr, DMA_FROM_DEVICE);

        iser_dto_add_regd_buff(recv_dto, regd_hdr, 0, 0);

        regd_data = &rx_desc->data_regd_buf;
        memset(regd_data, 0, sizeof(struct iser_regd_buf));
        regd_data->device  = device;
        regd_data->virt_addr  = rx_desc->data;
        regd_data->data_size  = rx_data_size;

        iser_reg_single(device, regd_data, DMA_FROM_DEVICE);

        iser_dto_add_regd_buff(recv_dto, regd_data, 0, 0);

        err = iser_post_recv(rx_desc);
        if (!err)
                return 0;

        /* iser_post_recv failed */
        iser_dto_buffs_release(recv_dto);
        kfree(rx_desc->data);
post_rx_kmalloc_failure:
        kmem_cache_free(ig.desc_cache, rx_desc);
        return err;
}

/* creates a new tx descriptor and adds header regd buffer */
static void iser_create_send_desc(struct iscsi_iser_conn *iser_conn,
                                  struct iser_desc       *tx_desc)
{
        struct iser_regd_buf *regd_hdr = &tx_desc->hdr_regd_buf;
        struct iser_dto      *send_dto = &tx_desc->dto;

        memset(regd_hdr, 0, sizeof(struct iser_regd_buf));
        regd_hdr->device  = iser_conn->ib_conn->device;
        regd_hdr->virt_addr  = tx_desc; /* == &tx_desc->iser_header */
        regd_hdr->data_size  = ISER_TOTAL_HEADERS_LEN;

        send_dto->ib_conn         = iser_conn->ib_conn;
        send_dto->notify_enable   = 1;
        send_dto->regd_vector_len = 0;

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

        iser_dto_add_regd_buff(send_dto, regd_hdr, 0, 0);
}

/**
 *  iser_conn_set_full_featured_mode - (iSER API)
 */
int iser_conn_set_full_featured_mode(struct iscsi_conn *conn)
{
        struct iscsi_iser_conn *iser_conn = conn->dd_data;

        int i;
        /* no need to keep it in a var, we are after login so if this should
         * be negotiated, by now the result should be available here */
        int initial_post_recv_bufs_num = ISER_MAX_RX_MISC_PDUS;

        iser_dbg("Initially post: %d\n", initial_post_recv_bufs_num);

        /* Check that there is no posted recv or send buffers left - */
        /* they must be consumed during the login phase */
        BUG_ON(atomic_read(&iser_conn->ib_conn->post_recv_buf_count) != 0);
        BUG_ON(atomic_read(&iser_conn->ib_conn->post_send_buf_count) != 0);

        /* Initial post receive buffers */
        for (i = 0; i < initial_post_recv_bufs_num; i++) {
                if (iser_post_receive_control(conn) != 0) {
                        iser_err("Failed to post recv bufs at:%d conn:0x%p\n",
                                 i, conn);
                        return -ENOMEM;
                }
        }
        iser_dbg("Posted %d post recv bufs, conn:0x%p\n", i, conn);
        return 0;
}

static int
iser_check_xmit(struct iscsi_conn *conn, void *task)
{
        struct iscsi_iser_conn *iser_conn = conn->dd_data;

        if (atomic_read(&iser_conn->ib_conn->post_send_buf_count) ==
            ISER_QP_MAX_REQ_DTOS) {
                iser_dbg("%ld can't xmit task %p\n",jiffies,task);
                return -ENOBUFS;
        }
        return 0;
}


/**
 * iser_send_command - send command PDU
 */
int iser_send_command(struct iscsi_conn     *conn,
                      struct iscsi_cmd_task *ctask)
{
        struct iscsi_iser_conn *iser_conn = conn->dd_data;
        struct iscsi_iser_cmd_task *iser_ctask = ctask->dd_data;
        struct iser_dto *send_dto = NULL;
        unsigned long edtl;
        int err = 0;
        struct iser_data_buf *data_buf;

        struct iscsi_cmd *hdr =  ctask->hdr;
        struct scsi_cmnd *sc  =  ctask->sc;

        if (!iser_conn_state_comp(iser_conn->ib_conn, ISER_CONN_UP)) {
                iser_err("Failed to send, conn: 0x%p is not up\n", iser_conn->ib_conn);
                return -EPERM;
        }
        if (iser_check_xmit(conn, ctask))
                return -ENOBUFS;

        edtl = ntohl(hdr->data_length);

        /* build the tx desc regd header and add it to the tx desc dto */
        iser_ctask->desc.type = ISCSI_TX_SCSI_COMMAND;
        send_dto = &iser_ctask->desc.dto;
        send_dto->ctask = iser_ctask;
        iser_create_send_desc(iser_conn, &iser_ctask->desc);

        if (hdr->flags & ISCSI_FLAG_CMD_READ)
                data_buf = &iser_ctask->data[ISER_DIR_IN];
        else
                data_buf = &iser_ctask->data[ISER_DIR_OUT];

        if (scsi_sg_count(sc)) { /* using a scatter list */
                data_buf->buf  = scsi_sglist(sc);
                data_buf->size = scsi_sg_count(sc);
        }

        data_buf->data_len = scsi_bufflen(sc);

        if (hdr->flags & ISCSI_FLAG_CMD_READ) {
                err = iser_prepare_read_cmd(ctask, edtl);
                if (err)
                        goto send_command_error;
        }
        if (hdr->flags & ISCSI_FLAG_CMD_WRITE) {
                err = iser_prepare_write_cmd(ctask,
                                             ctask->imm_count,
                                             ctask->imm_count +
                                             ctask->unsol_count,
                                             edtl);
                if (err)
                        goto send_command_error;
        }

        iser_reg_single(iser_conn->ib_conn->device,
                        send_dto->regd[0], DMA_TO_DEVICE);

        if (iser_post_receive_control(conn) != 0) {
                iser_err("post_recv failed!\n");
                err = -ENOMEM;
                goto send_command_error;
        }

        iser_ctask->status = ISER_TASK_STATUS_STARTED;

        err = iser_post_send(&iser_ctask->desc);
        if (!err)
                return 0;

send_command_error:
        iser_dto_buffs_release(send_dto);
        iser_err("conn %p failed ctask->itt %d err %d\n",conn, ctask->itt, err);
        return err;
}

/**
 * iser_send_data_out - send data out PDU
 */
int iser_send_data_out(struct iscsi_conn     *conn,
                       struct iscsi_cmd_task *ctask,
                       struct iscsi_data *hdr)
{
        struct iscsi_iser_conn *iser_conn = conn->dd_data;
        struct iscsi_iser_cmd_task *iser_ctask = ctask->dd_data;
        struct iser_desc *tx_desc = NULL;
        struct iser_dto *send_dto = NULL;
        unsigned long buf_offset;
        unsigned long data_seg_len;
        unsigned int itt;
        int err = 0;

        if (!iser_conn_state_comp(iser_conn->ib_conn, ISER_CONN_UP)) {
                iser_err("Failed to send, conn: 0x%p is not up\n", iser_conn->ib_conn);
                return -EPERM;
        }

        if (iser_check_xmit(conn, ctask))
                return -ENOBUFS;

        itt = ntohl(hdr->itt);
        data_seg_len = ntoh24(hdr->dlength);
        buf_offset   = ntohl(hdr->offset);

        iser_dbg("%s itt %d dseg_len %d offset %d\n",
                 __func__,(int)itt,(int)data_seg_len,(int)buf_offset);

        tx_desc = kmem_cache_alloc(ig.desc_cache, GFP_NOIO);
        if (tx_desc == NULL) {
                iser_err("Failed to alloc desc for post dataout\n");
                return -ENOMEM;
        }

        tx_desc->type = ISCSI_TX_DATAOUT;
        memcpy(&tx_desc->iscsi_header, hdr, sizeof(struct iscsi_hdr));

        /* build the tx desc regd header and add it to the tx desc dto */
        send_dto = &tx_desc->dto;
        send_dto->ctask = iser_ctask;
        iser_create_send_desc(iser_conn, tx_desc);

        iser_reg_single(iser_conn->ib_conn->device,
                        send_dto->regd[0], DMA_TO_DEVICE);

        /* all data was registered for RDMA, we can use the lkey */
        iser_dto_add_regd_buff(send_dto,
                               &iser_ctask->rdma_regd[ISER_DIR_OUT],
                               buf_offset,
                               data_seg_len);

        if (buf_offset + data_seg_len > iser_ctask->data[ISER_DIR_OUT].data_len) {
                iser_err("Offset:%ld & DSL:%ld in Data-Out "
                         "inconsistent with total len:%ld, itt:%d\n",
                         buf_offset, data_seg_len,
                         iser_ctask->data[ISER_DIR_OUT].data_len, itt);
                err = -EINVAL;
                goto send_data_out_error;
        }
        iser_dbg("data-out itt: %d, offset: %ld, sz: %ld\n",
                 itt, buf_offset, data_seg_len);


        err = iser_post_send(tx_desc);
        if (!err)
                return 0;

send_data_out_error:
        iser_dto_buffs_release(send_dto);
        kmem_cache_free(ig.desc_cache, tx_desc);
        iser_err("conn %p failed err %d\n",conn, err);
        return err;
}

int iser_send_control(struct iscsi_conn *conn,
                      struct iscsi_mgmt_task *mtask)
{
        struct iscsi_iser_conn *iser_conn = conn->dd_data;
        struct iser_desc *mdesc = mtask->dd_data;
        struct iser_dto *send_dto = NULL;
        unsigned long data_seg_len;
        int err = 0;
        struct iser_regd_buf *regd_buf;
        struct iser_device *device;

        if (!iser_conn_state_comp(iser_conn->ib_conn, ISER_CONN_UP)) {
                iser_err("Failed to send, conn: 0x%p is not up\n", iser_conn->ib_conn);
                return -EPERM;
        }

        if (iser_check_xmit(conn,mtask))
                return -ENOBUFS;

        /* build the tx desc regd header and add it to the tx desc dto */
        mdesc->type = ISCSI_TX_CONTROL;
        send_dto = &mdesc->dto;
        send_dto->ctask = NULL;
        iser_create_send_desc(iser_conn, mdesc);

        device = iser_conn->ib_conn->device;

        iser_reg_single(device, send_dto->regd[0], DMA_TO_DEVICE);

        data_seg_len = ntoh24(mtask->hdr->dlength);

        if (data_seg_len > 0) {
                regd_buf = &mdesc->data_regd_buf;
                memset(regd_buf, 0, sizeof(struct iser_regd_buf));
                regd_buf->device = device;
                regd_buf->virt_addr = mtask->data;
                regd_buf->data_size = mtask->data_count;
                iser_reg_single(device, regd_buf,
                                DMA_TO_DEVICE);
                iser_dto_add_regd_buff(send_dto, regd_buf,
                                       0,
                                       data_seg_len);
        }

        if (iser_post_receive_control(conn) != 0) {
                iser_err("post_rcv_buff failed!\n");
                err = -ENOMEM;
                goto send_control_error;
        }

        err = iser_post_send(mdesc);
        if (!err)
                return 0;

send_control_error:
        iser_dto_buffs_release(send_dto);
        iser_err("conn %p failed err %d\n",conn, err);
        return err;
}

/**
 * iser_rcv_dto_completion - recv DTO completion
 */
void iser_rcv_completion(struct iser_desc *rx_desc,
                         unsigned long dto_xfer_len)
{
        struct iser_dto        *dto = &rx_desc->dto;
        struct iscsi_iser_conn *conn = dto->ib_conn->iser_conn;
        struct iscsi_session *session = conn->iscsi_conn->session;
        struct iscsi_cmd_task *ctask;
        struct iscsi_iser_cmd_task *iser_ctask;
        struct iscsi_hdr *hdr;
        char   *rx_data = NULL;
        int     rx_data_len = 0;
        unsigned int itt;
        unsigned char opcode;

        hdr = &rx_desc->iscsi_header;

        iser_dbg("op 0x%x itt 0x%x\n", hdr->opcode,hdr->itt);

        if (dto_xfer_len > ISER_TOTAL_HEADERS_LEN) { /* we have data */
                rx_data_len = dto_xfer_len - ISER_TOTAL_HEADERS_LEN;
                rx_data     = dto->regd[1]->virt_addr;
                rx_data    += dto->offset[1];
        }

        opcode = hdr->opcode & ISCSI_OPCODE_MASK;

        if (opcode == ISCSI_OP_SCSI_CMD_RSP) {
                itt = get_itt(hdr->itt); /* mask out cid and age bits */
                if (!(itt < session->cmds_max))
                        iser_err("itt can't be matched to task!!!"
                                 "conn %p opcode %d cmds_max %d itt %d\n",
                                 conn->iscsi_conn,opcode,session->cmds_max,itt);
                /* use the mapping given with the cmds array indexed by itt */
                ctask = (struct iscsi_cmd_task *)session->cmds[itt];
                iser_ctask = ctask->dd_data;
                iser_dbg("itt %d ctask %p\n",itt,ctask);
                iser_ctask->status = ISER_TASK_STATUS_COMPLETED;
                iser_ctask_rdma_finalize(iser_ctask);
        }

        iser_dto_buffs_release(dto);

        iscsi_iser_recv(conn->iscsi_conn, hdr, rx_data, rx_data_len);

        kfree(rx_desc->data);
        kmem_cache_free(ig.desc_cache, rx_desc);

        /* decrementing conn->post_recv_buf_count only --after-- freeing the   *
         * task eliminates the need to worry on tasks which are completed in   *
         * parallel to the execution of iser_conn_term. So the code that waits *
         * for the posted rx bufs refcount to become zero handles everything   */
        atomic_dec(&conn->ib_conn->post_recv_buf_count);
}

void iser_snd_completion(struct iser_desc *tx_desc)
{
        struct iser_dto        *dto = &tx_desc->dto;
        struct iser_conn       *ib_conn = dto->ib_conn;
        struct iscsi_iser_conn *iser_conn = ib_conn->iser_conn;
        struct iscsi_conn      *conn = iser_conn->iscsi_conn;
        struct iscsi_mgmt_task *mtask;
        int resume_tx = 0;

        iser_dbg("Initiator, Data sent dto=0x%p\n", dto);

        iser_dto_buffs_release(dto);

        if (tx_desc->type == ISCSI_TX_DATAOUT)
                kmem_cache_free(ig.desc_cache, tx_desc);

        if (atomic_read(&iser_conn->ib_conn->post_send_buf_count) ==
            ISER_QP_MAX_REQ_DTOS)
                resume_tx = 1;

        atomic_dec(&ib_conn->post_send_buf_count);

        if (resume_tx) {
                iser_dbg("%ld resuming tx\n",jiffies);
                scsi_queue_work(conn->session->host, &conn->xmitwork);
        }

        if (tx_desc->type == ISCSI_TX_CONTROL) {
                /* this arithmetic is legal by libiscsi dd_data allocation */
                mtask = (void *) ((long)(void *)tx_desc -
                                  sizeof(struct iscsi_mgmt_task));
                if (mtask->hdr->itt == RESERVED_ITT) {
                        struct iscsi_session *session = conn->session;

                        spin_lock(&conn->session->lock);
                        list_del(&mtask->running);
                        __kfifo_put(session->mgmtpool.queue, (void*)&mtask,
                                    sizeof(void*));
                        spin_unlock(&session->lock);
                }
        }
}

void iser_ctask_rdma_init(struct iscsi_iser_cmd_task *iser_ctask)

{
        iser_ctask->status = ISER_TASK_STATUS_INIT;

        iser_ctask->dir[ISER_DIR_IN] = 0;
        iser_ctask->dir[ISER_DIR_OUT] = 0;

        iser_ctask->data[ISER_DIR_IN].data_len  = 0;
        iser_ctask->data[ISER_DIR_OUT].data_len = 0;

        memset(&iser_ctask->rdma_regd[ISER_DIR_IN], 0,
               sizeof(struct iser_regd_buf));
        memset(&iser_ctask->rdma_regd[ISER_DIR_OUT], 0,
               sizeof(struct iser_regd_buf));
}

void iser_ctask_rdma_finalize(struct iscsi_iser_cmd_task *iser_ctask)
{
        int deferred;
        int is_rdma_aligned = 1;
        struct iser_regd_buf *regd;

        /* if we were reading, copy back to unaligned sglist,
         * anyway dma_unmap and free the copy
         */
        if (iser_ctask->data_copy[ISER_DIR_IN].copy_buf != NULL) {
                is_rdma_aligned = 0;
                iser_finalize_rdma_unaligned_sg(iser_ctask, ISER_DIR_IN);
        }
        if (iser_ctask->data_copy[ISER_DIR_OUT].copy_buf != NULL) {
                is_rdma_aligned = 0;
                iser_finalize_rdma_unaligned_sg(iser_ctask, ISER_DIR_OUT);
        }

        if (iser_ctask->dir[ISER_DIR_IN]) {
                regd = &iser_ctask->rdma_regd[ISER_DIR_IN];
                deferred = iser_regd_buff_release(regd);
                if (deferred) {
                        iser_err("%d references remain for BUF-IN rdma reg\n",
                                 atomic_read(&regd->ref_count));
                }
        }

        if (iser_ctask->dir[ISER_DIR_OUT]) {
                regd = &iser_ctask->rdma_regd[ISER_DIR_OUT];
                deferred = iser_regd_buff_release(regd);
                if (deferred) {
                        iser_err("%d references remain for BUF-OUT rdma reg\n",
                                 atomic_read(&regd->ref_count));
                }
        }

       /* if the data was unaligned, it was already unmapped and then copied */
       if (is_rdma_aligned)
                iser_dma_unmap_task_data(iser_ctask);
}

void iser_dto_buffs_release(struct iser_dto *dto)
{
        int i;

        for (i = 0; i < dto->regd_vector_len; i++)
                iser_regd_buff_release(dto->regd[i]);
}