[mirror_ubuntu-artful-kernel.git] / drivers / target / iscsi / iscsi_target_util.c

/*******************************************************************************
 * This file contains the iSCSI Target specific utility functions.
 *
 * \u00a9 Copyright 2007-2011 RisingTide Systems LLC.
 *
 * Licensed to the Linux Foundation under the General Public License (GPL) version 2.
 *
 * Author: Nicholas A. Bellinger <nab@linux-iscsi.org>
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation; either version 2 of the License, or
 * (at your option) any later version.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 ******************************************************************************/

#include <linux/list.h>
#include <scsi/scsi_tcq.h>
#include <scsi/iscsi_proto.h>
#include <target/target_core_base.h>
#include <target/target_core_fabric.h>
#include <target/target_core_configfs.h>
#include <target/iscsi/iscsi_transport.h>

#include "iscsi_target_core.h"
#include "iscsi_target_parameters.h"
#include "iscsi_target_seq_pdu_list.h"
#include "iscsi_target_datain_values.h"
#include "iscsi_target_erl0.h"
#include "iscsi_target_erl1.h"
#include "iscsi_target_erl2.h"
#include "iscsi_target_tpg.h"
#include "iscsi_target_tq.h"
#include "iscsi_target_util.h"
#include "iscsi_target.h"

#define PRINT_BUFF(buff, len)                                   \
{                                                               \
        int zzz;                                                \
                                                                \
        pr_debug("%d:\n", __LINE__);                            \
        for (zzz = 0; zzz < len; zzz++) {                       \
                if (zzz % 16 == 0) {                            \
                        if (zzz)                                \
                                pr_debug("\n");                 \
                        pr_debug("%4i: ", zzz);                 \
                }                                               \
                pr_debug("%02x ", (unsigned char) (buff)[zzz]); \
        }                                                       \
        if ((len + 1) % 16)                                     \
                pr_debug("\n");                                 \
}

extern struct list_head g_tiqn_list;
extern spinlock_t tiqn_lock;

/*
 *      Called with cmd->r2t_lock held.
 */
int iscsit_add_r2t_to_list(
        struct iscsi_cmd *cmd,
        u32 offset,
        u32 xfer_len,
        int recovery,
        u32 r2t_sn)
{
        struct iscsi_r2t *r2t;

        r2t = kmem_cache_zalloc(lio_r2t_cache, GFP_ATOMIC);
        if (!r2t) {
                pr_err("Unable to allocate memory for struct iscsi_r2t.\n");
                return -1;
        }
        INIT_LIST_HEAD(&r2t->r2t_list);

        r2t->recovery_r2t = recovery;
        r2t->r2t_sn = (!r2t_sn) ? cmd->r2t_sn++ : r2t_sn;
        r2t->offset = offset;
        r2t->xfer_len = xfer_len;
        list_add_tail(&r2t->r2t_list, &cmd->cmd_r2t_list);
        spin_unlock_bh(&cmd->r2t_lock);

        iscsit_add_cmd_to_immediate_queue(cmd, cmd->conn, ISTATE_SEND_R2T);

        spin_lock_bh(&cmd->r2t_lock);
        return 0;
}

struct iscsi_r2t *iscsit_get_r2t_for_eos(
        struct iscsi_cmd *cmd,
        u32 offset,
        u32 length)
{
        struct iscsi_r2t *r2t;

        spin_lock_bh(&cmd->r2t_lock);
        list_for_each_entry(r2t, &cmd->cmd_r2t_list, r2t_list) {
                if ((r2t->offset <= offset) &&
                    (r2t->offset + r2t->xfer_len) >= (offset + length)) {
                        spin_unlock_bh(&cmd->r2t_lock);
                        return r2t;
                }
        }
        spin_unlock_bh(&cmd->r2t_lock);

        pr_err("Unable to locate R2T for Offset: %u, Length:"
                        " %u\n", offset, length);
        return NULL;
}

struct iscsi_r2t *iscsit_get_r2t_from_list(struct iscsi_cmd *cmd)
{
        struct iscsi_r2t *r2t;

        spin_lock_bh(&cmd->r2t_lock);
        list_for_each_entry(r2t, &cmd->cmd_r2t_list, r2t_list) {
                if (!r2t->sent_r2t) {
                        spin_unlock_bh(&cmd->r2t_lock);
                        return r2t;
                }
        }
        spin_unlock_bh(&cmd->r2t_lock);

        pr_err("Unable to locate next R2T to send for ITT:"
                        " 0x%08x.\n", cmd->init_task_tag);
        return NULL;
}

/*
 *      Called with cmd->r2t_lock held.
 */
void iscsit_free_r2t(struct iscsi_r2t *r2t, struct iscsi_cmd *cmd)
{
        list_del(&r2t->r2t_list);
        kmem_cache_free(lio_r2t_cache, r2t);
}

void iscsit_free_r2ts_from_list(struct iscsi_cmd *cmd)
{
        struct iscsi_r2t *r2t, *r2t_tmp;

        spin_lock_bh(&cmd->r2t_lock);
        list_for_each_entry_safe(r2t, r2t_tmp, &cmd->cmd_r2t_list, r2t_list)
                iscsit_free_r2t(r2t, cmd);
        spin_unlock_bh(&cmd->r2t_lock);
}

/*
 * May be called from software interrupt (timer) context for allocating
 * iSCSI NopINs.
 */
struct iscsi_cmd *iscsit_allocate_cmd(struct iscsi_conn *conn, gfp_t gfp_mask)
{
        struct iscsi_cmd *cmd;
        int priv_size = conn->conn_transport->priv_size;

        cmd = kzalloc(sizeof(struct iscsi_cmd) + priv_size, gfp_mask);
        if (!cmd) {
                pr_err("Unable to allocate memory for struct iscsi_cmd.\n");
                return NULL;
        }
        cmd->conn = conn;
        INIT_LIST_HEAD(&cmd->i_conn_node);
        INIT_LIST_HEAD(&cmd->datain_list);
        INIT_LIST_HEAD(&cmd->cmd_r2t_list);
        spin_lock_init(&cmd->datain_lock);
        spin_lock_init(&cmd->dataout_timeout_lock);
        spin_lock_init(&cmd->istate_lock);
        spin_lock_init(&cmd->error_lock);
        spin_lock_init(&cmd->r2t_lock);

        return cmd;
}
EXPORT_SYMBOL(iscsit_allocate_cmd);

struct iscsi_seq *iscsit_get_seq_holder_for_datain(
        struct iscsi_cmd *cmd,
        u32 seq_send_order)
{
        u32 i;

        for (i = 0; i < cmd->seq_count; i++)
                if (cmd->seq_list[i].seq_send_order == seq_send_order)
                        return &cmd->seq_list[i];

        return NULL;
}

struct iscsi_seq *iscsit_get_seq_holder_for_r2t(struct iscsi_cmd *cmd)
{
        u32 i;

        if (!cmd->seq_list) {
                pr_err("struct iscsi_cmd->seq_list is NULL!\n");
                return NULL;
        }

        for (i = 0; i < cmd->seq_count; i++) {
                if (cmd->seq_list[i].type != SEQTYPE_NORMAL)
                        continue;
                if (cmd->seq_list[i].seq_send_order == cmd->seq_send_order) {
                        cmd->seq_send_order++;
                        return &cmd->seq_list[i];
                }
        }

        return NULL;
}

struct iscsi_r2t *iscsit_get_holder_for_r2tsn(
        struct iscsi_cmd *cmd,
        u32 r2t_sn)
{
        struct iscsi_r2t *r2t;

        spin_lock_bh(&cmd->r2t_lock);
        list_for_each_entry(r2t, &cmd->cmd_r2t_list, r2t_list) {
                if (r2t->r2t_sn == r2t_sn) {
                        spin_unlock_bh(&cmd->r2t_lock);
                        return r2t;
                }
        }
        spin_unlock_bh(&cmd->r2t_lock);

        return NULL;
}

static inline int iscsit_check_received_cmdsn(struct iscsi_session *sess, u32 cmdsn)
{
        int ret;

        /*
         * This is the proper method of checking received CmdSN against
         * ExpCmdSN and MaxCmdSN values, as well as accounting for out
         * or order CmdSNs due to multiple connection sessions and/or
         * CRC failures.
         */
        if (iscsi_sna_gt(cmdsn, sess->max_cmd_sn)) {
                pr_err("Received CmdSN: 0x%08x is greater than"
                       " MaxCmdSN: 0x%08x, protocol error.\n", cmdsn,
                       sess->max_cmd_sn);
                ret = CMDSN_ERROR_CANNOT_RECOVER;

        } else if (cmdsn == sess->exp_cmd_sn) {
                sess->exp_cmd_sn++;
                pr_debug("Received CmdSN matches ExpCmdSN,"
                      " incremented ExpCmdSN to: 0x%08x\n",
                      sess->exp_cmd_sn);
                ret = CMDSN_NORMAL_OPERATION;

        } else if (iscsi_sna_gt(cmdsn, sess->exp_cmd_sn)) {
                pr_debug("Received CmdSN: 0x%08x is greater"
                      " than ExpCmdSN: 0x%08x, not acknowledging.\n",
                      cmdsn, sess->exp_cmd_sn);
                ret = CMDSN_HIGHER_THAN_EXP;

        } else {
                pr_err("Received CmdSN: 0x%08x is less than"
                       " ExpCmdSN: 0x%08x, ignoring.\n", cmdsn,
                       sess->exp_cmd_sn);
                ret = CMDSN_LOWER_THAN_EXP;
        }

        return ret;
}

/*
 * Commands may be received out of order if MC/S is in use.
 * Ensure they are executed in CmdSN order.
 */
int iscsit_sequence_cmd(struct iscsi_conn *conn, struct iscsi_cmd *cmd,
                        unsigned char *buf, __be32 cmdsn)
{
        int ret, cmdsn_ret;
        bool reject = false;
        u8 reason = ISCSI_REASON_BOOKMARK_NO_RESOURCES;

        mutex_lock(&conn->sess->cmdsn_mutex);

        cmdsn_ret = iscsit_check_received_cmdsn(conn->sess, be32_to_cpu(cmdsn));
        switch (cmdsn_ret) {
        case CMDSN_NORMAL_OPERATION:
                ret = iscsit_execute_cmd(cmd, 0);
                if ((ret >= 0) && !list_empty(&conn->sess->sess_ooo_cmdsn_list))
                        iscsit_execute_ooo_cmdsns(conn->sess);
                else if (ret < 0) {
                        reject = true;
                        ret = CMDSN_ERROR_CANNOT_RECOVER;
                }
                break;
        case CMDSN_HIGHER_THAN_EXP:
                ret = iscsit_handle_ooo_cmdsn(conn->sess, cmd, be32_to_cpu(cmdsn));
                if (ret < 0) {
                        reject = true;
                        ret = CMDSN_ERROR_CANNOT_RECOVER;
                        break;
                }
                ret = CMDSN_HIGHER_THAN_EXP;
                break;
        case CMDSN_LOWER_THAN_EXP:
                cmd->i_state = ISTATE_REMOVE;
                iscsit_add_cmd_to_immediate_queue(cmd, conn, cmd->i_state);
                ret = cmdsn_ret;
                break;
        default:
                reason = ISCSI_REASON_PROTOCOL_ERROR;
                reject = true;
                ret = cmdsn_ret;
                break;
        }
        mutex_unlock(&conn->sess->cmdsn_mutex);

        if (reject)
                iscsit_reject_cmd(cmd, reason, buf);

        return ret;
}
EXPORT_SYMBOL(iscsit_sequence_cmd);

int iscsit_check_unsolicited_dataout(struct iscsi_cmd *cmd, unsigned char *buf)
{
        struct iscsi_conn *conn = cmd->conn;
        struct se_cmd *se_cmd = &cmd->se_cmd;
        struct iscsi_data *hdr = (struct iscsi_data *) buf;
        u32 payload_length = ntoh24(hdr->dlength);

        if (conn->sess->sess_ops->InitialR2T) {
                pr_err("Received unexpected unsolicited data"
                        " while InitialR2T=Yes, protocol error.\n");
                transport_send_check_condition_and_sense(se_cmd,
                                TCM_UNEXPECTED_UNSOLICITED_DATA, 0);
                return -1;
        }

        if ((cmd->first_burst_len + payload_length) >
             conn->sess->sess_ops->FirstBurstLength) {
                pr_err("Total %u bytes exceeds FirstBurstLength: %u"
                        " for this Unsolicited DataOut Burst.\n",
                        (cmd->first_burst_len + payload_length),
                                conn->sess->sess_ops->FirstBurstLength);
                transport_send_check_condition_and_sense(se_cmd,
                                TCM_INCORRECT_AMOUNT_OF_DATA, 0);
                return -1;
        }

        if (!(hdr->flags & ISCSI_FLAG_CMD_FINAL))
                return 0;

        if (((cmd->first_burst_len + payload_length) != cmd->se_cmd.data_length) &&
            ((cmd->first_burst_len + payload_length) !=
              conn->sess->sess_ops->FirstBurstLength)) {
                pr_err("Unsolicited non-immediate data received %u"
                        " does not equal FirstBurstLength: %u, and does"
                        " not equal ExpXferLen %u.\n",
                        (cmd->first_burst_len + payload_length),
                        conn->sess->sess_ops->FirstBurstLength, cmd->se_cmd.data_length);
                transport_send_check_condition_and_sense(se_cmd,
                                TCM_INCORRECT_AMOUNT_OF_DATA, 0);
                return -1;
        }
        return 0;
}

struct iscsi_cmd *iscsit_find_cmd_from_itt(
        struct iscsi_conn *conn,
        itt_t init_task_tag)
{
        struct iscsi_cmd *cmd;

        spin_lock_bh(&conn->cmd_lock);
        list_for_each_entry(cmd, &conn->conn_cmd_list, i_conn_node) {
                if (cmd->init_task_tag == init_task_tag) {
                        spin_unlock_bh(&conn->cmd_lock);
                        return cmd;
                }
        }
        spin_unlock_bh(&conn->cmd_lock);

        pr_err("Unable to locate ITT: 0x%08x on CID: %hu",
                        init_task_tag, conn->cid);
        return NULL;
}

struct iscsi_cmd *iscsit_find_cmd_from_itt_or_dump(
        struct iscsi_conn *conn,
        itt_t init_task_tag,
        u32 length)
{
        struct iscsi_cmd *cmd;

        spin_lock_bh(&conn->cmd_lock);
        list_for_each_entry(cmd, &conn->conn_cmd_list, i_conn_node) {
                if (cmd->init_task_tag == init_task_tag) {
                        spin_unlock_bh(&conn->cmd_lock);
                        return cmd;
                }
        }
        spin_unlock_bh(&conn->cmd_lock);

        pr_err("Unable to locate ITT: 0x%08x on CID: %hu,"
                        " dumping payload\n", init_task_tag, conn->cid);
        if (length)
                iscsit_dump_data_payload(conn, length, 1);

        return NULL;
}

struct iscsi_cmd *iscsit_find_cmd_from_ttt(
        struct iscsi_conn *conn,
        u32 targ_xfer_tag)
{
        struct iscsi_cmd *cmd = NULL;

        spin_lock_bh(&conn->cmd_lock);
        list_for_each_entry(cmd, &conn->conn_cmd_list, i_conn_node) {
                if (cmd->targ_xfer_tag == targ_xfer_tag) {
                        spin_unlock_bh(&conn->cmd_lock);
                        return cmd;
                }
        }
        spin_unlock_bh(&conn->cmd_lock);

        pr_err("Unable to locate TTT: 0x%08x on CID: %hu\n",
                        targ_xfer_tag, conn->cid);
        return NULL;
}

int iscsit_find_cmd_for_recovery(
        struct iscsi_session *sess,
        struct iscsi_cmd **cmd_ptr,
        struct iscsi_conn_recovery **cr_ptr,
        itt_t init_task_tag)
{
        struct iscsi_cmd *cmd = NULL;
        struct iscsi_conn_recovery *cr;
        /*
         * Scan through the inactive connection recovery list's command list.
         * If init_task_tag matches the command is still alligent.
         */
        spin_lock(&sess->cr_i_lock);
        list_for_each_entry(cr, &sess->cr_inactive_list, cr_list) {
                spin_lock(&cr->conn_recovery_cmd_lock);
                list_for_each_entry(cmd, &cr->conn_recovery_cmd_list, i_conn_node) {
                        if (cmd->init_task_tag == init_task_tag) {
                                spin_unlock(&cr->conn_recovery_cmd_lock);
                                spin_unlock(&sess->cr_i_lock);

                                *cr_ptr = cr;
                                *cmd_ptr = cmd;
                                return -2;
                        }
                }
                spin_unlock(&cr->conn_recovery_cmd_lock);
        }
        spin_unlock(&sess->cr_i_lock);
        /*
         * Scan through the active connection recovery list's command list.
         * If init_task_tag matches the command is ready to be reassigned.
         */
        spin_lock(&sess->cr_a_lock);
        list_for_each_entry(cr, &sess->cr_active_list, cr_list) {
                spin_lock(&cr->conn_recovery_cmd_lock);
                list_for_each_entry(cmd, &cr->conn_recovery_cmd_list, i_conn_node) {
                        if (cmd->init_task_tag == init_task_tag) {
                                spin_unlock(&cr->conn_recovery_cmd_lock);
                                spin_unlock(&sess->cr_a_lock);

                                *cr_ptr = cr;
                                *cmd_ptr = cmd;
                                return 0;
                        }
                }
                spin_unlock(&cr->conn_recovery_cmd_lock);
        }
        spin_unlock(&sess->cr_a_lock);

        return -1;
}

void iscsit_add_cmd_to_immediate_queue(
        struct iscsi_cmd *cmd,
        struct iscsi_conn *conn,
        u8 state)
{
        struct iscsi_queue_req *qr;

        qr = kmem_cache_zalloc(lio_qr_cache, GFP_ATOMIC);
        if (!qr) {
                pr_err("Unable to allocate memory for"
                                " struct iscsi_queue_req\n");
                return;
        }
        INIT_LIST_HEAD(&qr->qr_list);
        qr->cmd = cmd;
        qr->state = state;

        spin_lock_bh(&conn->immed_queue_lock);
        list_add_tail(&qr->qr_list, &conn->immed_queue_list);
        atomic_inc(&cmd->immed_queue_count);
        atomic_set(&conn->check_immediate_queue, 1);
        spin_unlock_bh(&conn->immed_queue_lock);

        wake_up(&conn->queues_wq);
}

struct iscsi_queue_req *iscsit_get_cmd_from_immediate_queue(struct iscsi_conn *conn)
{
        struct iscsi_queue_req *qr;

        spin_lock_bh(&conn->immed_queue_lock);
        if (list_empty(&conn->immed_queue_list)) {
                spin_unlock_bh(&conn->immed_queue_lock);
                return NULL;
        }
        qr = list_first_entry(&conn->immed_queue_list,
                              struct iscsi_queue_req, qr_list);

        list_del(&qr->qr_list);
        if (qr->cmd)
                atomic_dec(&qr->cmd->immed_queue_count);
        spin_unlock_bh(&conn->immed_queue_lock);

        return qr;
}

static void iscsit_remove_cmd_from_immediate_queue(
        struct iscsi_cmd *cmd,
        struct iscsi_conn *conn)
{
        struct iscsi_queue_req *qr, *qr_tmp;

        spin_lock_bh(&conn->immed_queue_lock);
        if (!atomic_read(&cmd->immed_queue_count)) {
                spin_unlock_bh(&conn->immed_queue_lock);
                return;
        }

        list_for_each_entry_safe(qr, qr_tmp, &conn->immed_queue_list, qr_list) {
                if (qr->cmd != cmd)
                        continue;

                atomic_dec(&qr->cmd->immed_queue_count);
                list_del(&qr->qr_list);
                kmem_cache_free(lio_qr_cache, qr);
        }
        spin_unlock_bh(&conn->immed_queue_lock);

        if (atomic_read(&cmd->immed_queue_count)) {
                pr_err("ITT: 0x%08x immed_queue_count: %d\n",
                        cmd->init_task_tag,
                        atomic_read(&cmd->immed_queue_count));
        }
}

void iscsit_add_cmd_to_response_queue(
        struct iscsi_cmd *cmd,
        struct iscsi_conn *conn,
        u8 state)
{
        struct iscsi_queue_req *qr;

        qr = kmem_cache_zalloc(lio_qr_cache, GFP_ATOMIC);
        if (!qr) {
                pr_err("Unable to allocate memory for"
                        " struct iscsi_queue_req\n");
                return;
        }
        INIT_LIST_HEAD(&qr->qr_list);
        qr->cmd = cmd;
        qr->state = state;

        spin_lock_bh(&conn->response_queue_lock);
        list_add_tail(&qr->qr_list, &conn->response_queue_list);
        atomic_inc(&cmd->response_queue_count);
        spin_unlock_bh(&conn->response_queue_lock);

        wake_up(&conn->queues_wq);
}

struct iscsi_queue_req *iscsit_get_cmd_from_response_queue(struct iscsi_conn *conn)
{
        struct iscsi_queue_req *qr;

        spin_lock_bh(&conn->response_queue_lock);
        if (list_empty(&conn->response_queue_list)) {
                spin_unlock_bh(&conn->response_queue_lock);
                return NULL;
        }

        qr = list_first_entry(&conn->response_queue_list,
                              struct iscsi_queue_req, qr_list);

        list_del(&qr->qr_list);
        if (qr->cmd)
                atomic_dec(&qr->cmd->response_queue_count);
        spin_unlock_bh(&conn->response_queue_lock);

        return qr;
}

static void iscsit_remove_cmd_from_response_queue(
        struct iscsi_cmd *cmd,
        struct iscsi_conn *conn)
{
        struct iscsi_queue_req *qr, *qr_tmp;

        spin_lock_bh(&conn->response_queue_lock);
        if (!atomic_read(&cmd->response_queue_count)) {
                spin_unlock_bh(&conn->response_queue_lock);
                return;
        }

        list_for_each_entry_safe(qr, qr_tmp, &conn->response_queue_list,
                                qr_list) {
                if (qr->cmd != cmd)
                        continue;

                atomic_dec(&qr->cmd->response_queue_count);
                list_del(&qr->qr_list);
                kmem_cache_free(lio_qr_cache, qr);
        }
        spin_unlock_bh(&conn->response_queue_lock);

        if (atomic_read(&cmd->response_queue_count)) {
                pr_err("ITT: 0x%08x response_queue_count: %d\n",
                        cmd->init_task_tag,
                        atomic_read(&cmd->response_queue_count));
        }
}

bool iscsit_conn_all_queues_empty(struct iscsi_conn *conn)
{
        bool empty;

        spin_lock_bh(&conn->immed_queue_lock);
        empty = list_empty(&conn->immed_queue_list);
        spin_unlock_bh(&conn->immed_queue_lock);

        if (!empty)
                return empty;

        spin_lock_bh(&conn->response_queue_lock);
        empty = list_empty(&conn->response_queue_list);
        spin_unlock_bh(&conn->response_queue_lock);

        return empty;
}

void iscsit_free_queue_reqs_for_conn(struct iscsi_conn *conn)
{
        struct iscsi_queue_req *qr, *qr_tmp;

        spin_lock_bh(&conn->immed_queue_lock);
        list_for_each_entry_safe(qr, qr_tmp, &conn->immed_queue_list, qr_list) {
                list_del(&qr->qr_list);
                if (qr->cmd)
                        atomic_dec(&qr->cmd->immed_queue_count);

                kmem_cache_free(lio_qr_cache, qr);
        }
        spin_unlock_bh(&conn->immed_queue_lock);

        spin_lock_bh(&conn->response_queue_lock);
        list_for_each_entry_safe(qr, qr_tmp, &conn->response_queue_list,
                        qr_list) {
                list_del(&qr->qr_list);
                if (qr->cmd)
                        atomic_dec(&qr->cmd->response_queue_count);

                kmem_cache_free(lio_qr_cache, qr);
        }
        spin_unlock_bh(&conn->response_queue_lock);
}

void iscsit_release_cmd(struct iscsi_cmd *cmd)
{
        kfree(cmd->buf_ptr);
        kfree(cmd->pdu_list);
        kfree(cmd->seq_list);
        kfree(cmd->tmr_req);
        kfree(cmd->iov_data);
        kfree(cmd->text_in_ptr);

        kfree(cmd);
}
EXPORT_SYMBOL(iscsit_release_cmd);

static void __iscsit_free_cmd(struct iscsi_cmd *cmd, bool scsi_cmd,
                              bool check_queues)
{
        struct iscsi_conn *conn = cmd->conn;

        if (scsi_cmd) {
                if (cmd->data_direction == DMA_TO_DEVICE) {
                        iscsit_stop_dataout_timer(cmd);
                        iscsit_free_r2ts_from_list(cmd);
                }
                if (cmd->data_direction == DMA_FROM_DEVICE)
                        iscsit_free_all_datain_reqs(cmd);
        }

        if (conn && check_queues) {
                iscsit_remove_cmd_from_immediate_queue(cmd, conn);
                iscsit_remove_cmd_from_response_queue(cmd, conn);
        }
}

void iscsit_free_cmd(struct iscsi_cmd *cmd, bool shutdown)
{
        struct se_cmd *se_cmd = NULL;
        int rc;
        /*
         * Determine if a struct se_cmd is associated with
         * this struct iscsi_cmd.
         */
        switch (cmd->iscsi_opcode) {
        case ISCSI_OP_SCSI_CMD:
                se_cmd = &cmd->se_cmd;
                __iscsit_free_cmd(cmd, true, shutdown);
                /*
                 * Fallthrough
                 */
        case ISCSI_OP_SCSI_TMFUNC:
                rc = transport_generic_free_cmd(&cmd->se_cmd, 1);
                if (!rc && shutdown && se_cmd && se_cmd->se_sess) {
                        __iscsit_free_cmd(cmd, true, shutdown);
                        target_put_sess_cmd(se_cmd->se_sess, se_cmd);
                }
                break;
        case ISCSI_OP_REJECT:
                /*
                 * 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) {
                        se_cmd = &cmd->se_cmd;
                        __iscsit_free_cmd(cmd, true, shutdown);

                        rc = transport_generic_free_cmd(&cmd->se_cmd, 1);
                        if (!rc && shutdown && se_cmd->se_sess) {
                                __iscsit_free_cmd(cmd, true, shutdown);
                                target_put_sess_cmd(se_cmd->se_sess, se_cmd);
                        }
                        break;
                }
                /* Fall-through */
        default:
                __iscsit_free_cmd(cmd, false, shutdown);
                iscsit_release_cmd(cmd);
                break;
        }
}

int iscsit_check_session_usage_count(struct iscsi_session *sess)
{
        spin_lock_bh(&sess->session_usage_lock);
        if (sess->session_usage_count != 0) {
                sess->session_waiting_on_uc = 1;
                spin_unlock_bh(&sess->session_usage_lock);
                if (in_interrupt())
                        return 2;

                wait_for_completion(&sess->session_waiting_on_uc_comp);
                return 1;
        }
        spin_unlock_bh(&sess->session_usage_lock);

        return 0;
}

void iscsit_dec_session_usage_count(struct iscsi_session *sess)
{
        spin_lock_bh(&sess->session_usage_lock);
        sess->session_usage_count--;

        if (!sess->session_usage_count && sess->session_waiting_on_uc)
                complete(&sess->session_waiting_on_uc_comp);

        spin_unlock_bh(&sess->session_usage_lock);
}

void iscsit_inc_session_usage_count(struct iscsi_session *sess)
{
        spin_lock_bh(&sess->session_usage_lock);
        sess->session_usage_count++;
        spin_unlock_bh(&sess->session_usage_lock);
}

/*
 *      Setup conn->if_marker and conn->of_marker values based upon
 *      the initial marker-less interval. (see iSCSI v19 A.2)
 */
int iscsit_set_sync_and_steering_values(struct iscsi_conn *conn)
{
        int login_ifmarker_count = 0, login_ofmarker_count = 0, next_marker = 0;
        /*
         * IFMarkInt and OFMarkInt are negotiated as 32-bit words.
         */
        u32 IFMarkInt = (conn->conn_ops->IFMarkInt * 4);
        u32 OFMarkInt = (conn->conn_ops->OFMarkInt * 4);

        if (conn->conn_ops->OFMarker) {
                /*
                 * Account for the first Login Command received not
                 * via iscsi_recv_msg().
                 */
                conn->of_marker += ISCSI_HDR_LEN;
                if (conn->of_marker <= OFMarkInt) {
                        conn->of_marker = (OFMarkInt - conn->of_marker);
                } else {
                        login_ofmarker_count = (conn->of_marker / OFMarkInt);
                        next_marker = (OFMarkInt * (login_ofmarker_count + 1)) +
                                        (login_ofmarker_count * MARKER_SIZE);
                        conn->of_marker = (next_marker - conn->of_marker);
                }
                conn->of_marker_offset = 0;
                pr_debug("Setting OFMarker value to %u based on Initial"
                        " Markerless Interval.\n", conn->of_marker);
        }

        if (conn->conn_ops->IFMarker) {
                if (conn->if_marker <= IFMarkInt) {
                        conn->if_marker = (IFMarkInt - conn->if_marker);
                } else {
                        login_ifmarker_count = (conn->if_marker / IFMarkInt);
                        next_marker = (IFMarkInt * (login_ifmarker_count + 1)) +
                                        (login_ifmarker_count * MARKER_SIZE);
                        conn->if_marker = (next_marker - conn->if_marker);
                }
                pr_debug("Setting IFMarker value to %u based on Initial"
                        " Markerless Interval.\n", conn->if_marker);
        }

        return 0;
}

struct iscsi_conn *iscsit_get_conn_from_cid(struct iscsi_session *sess, u16 cid)
{
        struct iscsi_conn *conn;

        spin_lock_bh(&sess->conn_lock);
        list_for_each_entry(conn, &sess->sess_conn_list, conn_list) {
                if ((conn->cid == cid) &&
                    (conn->conn_state == TARG_CONN_STATE_LOGGED_IN)) {
                        iscsit_inc_conn_usage_count(conn);
                        spin_unlock_bh(&sess->conn_lock);
                        return conn;
                }
        }
        spin_unlock_bh(&sess->conn_lock);

        return NULL;
}

struct iscsi_conn *iscsit_get_conn_from_cid_rcfr(struct iscsi_session *sess, u16 cid)
{
        struct iscsi_conn *conn;

        spin_lock_bh(&sess->conn_lock);
        list_for_each_entry(conn, &sess->sess_conn_list, conn_list) {
                if (conn->cid == cid) {
                        iscsit_inc_conn_usage_count(conn);
                        spin_lock(&conn->state_lock);
                        atomic_set(&conn->connection_wait_rcfr, 1);
                        spin_unlock(&conn->state_lock);
                        spin_unlock_bh(&sess->conn_lock);
                        return conn;
                }
        }
        spin_unlock_bh(&sess->conn_lock);

        return NULL;
}

void iscsit_check_conn_usage_count(struct iscsi_conn *conn)
{
        spin_lock_bh(&conn->conn_usage_lock);
        if (conn->conn_usage_count != 0) {
                conn->conn_waiting_on_uc = 1;
                spin_unlock_bh(&conn->conn_usage_lock);

                wait_for_completion(&conn->conn_waiting_on_uc_comp);
                return;
        }
        spin_unlock_bh(&conn->conn_usage_lock);
}

void iscsit_dec_conn_usage_count(struct iscsi_conn *conn)
{
        spin_lock_bh(&conn->conn_usage_lock);
        conn->conn_usage_count--;

        if (!conn->conn_usage_count && conn->conn_waiting_on_uc)
                complete(&conn->conn_waiting_on_uc_comp);

        spin_unlock_bh(&conn->conn_usage_lock);
}

void iscsit_inc_conn_usage_count(struct iscsi_conn *conn)
{
        spin_lock_bh(&conn->conn_usage_lock);
        conn->conn_usage_count++;
        spin_unlock_bh(&conn->conn_usage_lock);
}

static int iscsit_add_nopin(struct iscsi_conn *conn, int want_response)
{
        u8 state;
        struct iscsi_cmd *cmd;

        cmd = iscsit_allocate_cmd(conn, GFP_ATOMIC);
        if (!cmd)
                return -1;

        cmd->iscsi_opcode = ISCSI_OP_NOOP_IN;
        state = (want_response) ? ISTATE_SEND_NOPIN_WANT_RESPONSE :
                                ISTATE_SEND_NOPIN_NO_RESPONSE;
        cmd->init_task_tag = RESERVED_ITT;
        spin_lock_bh(&conn->sess->ttt_lock);
        cmd->targ_xfer_tag = (want_response) ? conn->sess->targ_xfer_tag++ :
                        0xFFFFFFFF;
        if (want_response && (cmd->targ_xfer_tag == 0xFFFFFFFF))
                cmd->targ_xfer_tag = conn->sess->targ_xfer_tag++;
        spin_unlock_bh(&conn->sess->ttt_lock);

        spin_lock_bh(&conn->cmd_lock);
        list_add_tail(&cmd->i_conn_node, &conn->conn_cmd_list);
        spin_unlock_bh(&conn->cmd_lock);

        if (want_response)
                iscsit_start_nopin_response_timer(conn);
        iscsit_add_cmd_to_immediate_queue(cmd, conn, state);

        return 0;
}

static void iscsit_handle_nopin_response_timeout(unsigned long data)
{
        struct iscsi_conn *conn = (struct iscsi_conn *) data;

        iscsit_inc_conn_usage_count(conn);

        spin_lock_bh(&conn->nopin_timer_lock);
        if (conn->nopin_response_timer_flags & ISCSI_TF_STOP) {
                spin_unlock_bh(&conn->nopin_timer_lock);
                iscsit_dec_conn_usage_count(conn);
                return;
        }

        pr_debug("Did not receive response to NOPIN on CID: %hu on"
                " SID: %u, failing connection.\n", conn->cid,
                        conn->sess->sid);
        conn->nopin_response_timer_flags &= ~ISCSI_TF_RUNNING;
        spin_unlock_bh(&conn->nopin_timer_lock);

        {
        struct iscsi_portal_group *tpg = conn->sess->tpg;
        struct iscsi_tiqn *tiqn = tpg->tpg_tiqn;

        if (tiqn) {
                spin_lock_bh(&tiqn->sess_err_stats.lock);
                strcpy(tiqn->sess_err_stats.last_sess_fail_rem_name,
                                conn->sess->sess_ops->InitiatorName);
                tiqn->sess_err_stats.last_sess_failure_type =
                                ISCSI_SESS_ERR_CXN_TIMEOUT;
                tiqn->sess_err_stats.cxn_timeout_errors++;
                conn->sess->conn_timeout_errors++;
                spin_unlock_bh(&tiqn->sess_err_stats.lock);
        }
        }

        iscsit_cause_connection_reinstatement(conn, 0);
        iscsit_dec_conn_usage_count(conn);
}

void iscsit_mod_nopin_response_timer(struct iscsi_conn *conn)
{
        struct iscsi_session *sess = conn->sess;
        struct iscsi_node_attrib *na = iscsit_tpg_get_node_attrib(sess);

        spin_lock_bh(&conn->nopin_timer_lock);
        if (!(conn->nopin_response_timer_flags & ISCSI_TF_RUNNING)) {
                spin_unlock_bh(&conn->nopin_timer_lock);
                return;
        }

        mod_timer(&conn->nopin_response_timer,
                (get_jiffies_64() + na->nopin_response_timeout * HZ));
        spin_unlock_bh(&conn->nopin_timer_lock);
}

/*
 *      Called with conn->nopin_timer_lock held.
 */
void iscsit_start_nopin_response_timer(struct iscsi_conn *conn)
{
        struct iscsi_session *sess = conn->sess;
        struct iscsi_node_attrib *na = iscsit_tpg_get_node_attrib(sess);

        spin_lock_bh(&conn->nopin_timer_lock);
        if (conn->nopin_response_timer_flags & ISCSI_TF_RUNNING) {
                spin_unlock_bh(&conn->nopin_timer_lock);
                return;
        }

        init_timer(&conn->nopin_response_timer);
        conn->nopin_response_timer.expires =
                (get_jiffies_64() + na->nopin_response_timeout * HZ);
        conn->nopin_response_timer.data = (unsigned long)conn;
        conn->nopin_response_timer.function = iscsit_handle_nopin_response_timeout;
        conn->nopin_response_timer_flags &= ~ISCSI_TF_STOP;
        conn->nopin_response_timer_flags |= ISCSI_TF_RUNNING;
        add_timer(&conn->nopin_response_timer);

        pr_debug("Started NOPIN Response Timer on CID: %d to %u"
                " seconds\n", conn->cid, na->nopin_response_timeout);
        spin_unlock_bh(&conn->nopin_timer_lock);
}

void iscsit_stop_nopin_response_timer(struct iscsi_conn *conn)
{
        spin_lock_bh(&conn->nopin_timer_lock);
        if (!(conn->nopin_response_timer_flags & ISCSI_TF_RUNNING)) {
                spin_unlock_bh(&conn->nopin_timer_lock);
                return;
        }
        conn->nopin_response_timer_flags |= ISCSI_TF_STOP;
        spin_unlock_bh(&conn->nopin_timer_lock);

        del_timer_sync(&conn->nopin_response_timer);

        spin_lock_bh(&conn->nopin_timer_lock);
        conn->nopin_response_timer_flags &= ~ISCSI_TF_RUNNING;
        spin_unlock_bh(&conn->nopin_timer_lock);
}

static void iscsit_handle_nopin_timeout(unsigned long data)
{
        struct iscsi_conn *conn = (struct iscsi_conn *) data;

        iscsit_inc_conn_usage_count(conn);

        spin_lock_bh(&conn->nopin_timer_lock);
        if (conn->nopin_timer_flags & ISCSI_TF_STOP) {
                spin_unlock_bh(&conn->nopin_timer_lock);
                iscsit_dec_conn_usage_count(conn);
                return;
        }
        conn->nopin_timer_flags &= ~ISCSI_TF_RUNNING;
        spin_unlock_bh(&conn->nopin_timer_lock);

        iscsit_add_nopin(conn, 1);
        iscsit_dec_conn_usage_count(conn);
}

/*
 * Called with conn->nopin_timer_lock held.
 */
void __iscsit_start_nopin_timer(struct iscsi_conn *conn)
{
        struct iscsi_session *sess = conn->sess;
        struct iscsi_node_attrib *na = iscsit_tpg_get_node_attrib(sess);
        /*
        * NOPIN timeout is disabled.
         */
        if (!na->nopin_timeout)
                return;

        if (conn->nopin_timer_flags & ISCSI_TF_RUNNING)
                return;

        init_timer(&conn->nopin_timer);
        conn->nopin_timer.expires = (get_jiffies_64() + na->nopin_timeout * HZ);
        conn->nopin_timer.data = (unsigned long)conn;
        conn->nopin_timer.function = iscsit_handle_nopin_timeout;
        conn->nopin_timer_flags &= ~ISCSI_TF_STOP;
        conn->nopin_timer_flags |= ISCSI_TF_RUNNING;
        add_timer(&conn->nopin_timer);

        pr_debug("Started NOPIN Timer on CID: %d at %u second"
                " interval\n", conn->cid, na->nopin_timeout);
}

void iscsit_start_nopin_timer(struct iscsi_conn *conn)
{
        struct iscsi_session *sess = conn->sess;
        struct iscsi_node_attrib *na = iscsit_tpg_get_node_attrib(sess);
        /*
         * NOPIN timeout is disabled..
         */
        if (!na->nopin_timeout)
                return;

        spin_lock_bh(&conn->nopin_timer_lock);
        if (conn->nopin_timer_flags & ISCSI_TF_RUNNING) {
                spin_unlock_bh(&conn->nopin_timer_lock);
                return;
        }

        init_timer(&conn->nopin_timer);
        conn->nopin_timer.expires = (get_jiffies_64() + na->nopin_timeout * HZ);
        conn->nopin_timer.data = (unsigned long)conn;
        conn->nopin_timer.function = iscsit_handle_nopin_timeout;
        conn->nopin_timer_flags &= ~ISCSI_TF_STOP;
        conn->nopin_timer_flags |= ISCSI_TF_RUNNING;
        add_timer(&conn->nopin_timer);

        pr_debug("Started NOPIN Timer on CID: %d at %u second"
                        " interval\n", conn->cid, na->nopin_timeout);
        spin_unlock_bh(&conn->nopin_timer_lock);
}

void iscsit_stop_nopin_timer(struct iscsi_conn *conn)
{
        spin_lock_bh(&conn->nopin_timer_lock);
        if (!(conn->nopin_timer_flags & ISCSI_TF_RUNNING)) {
                spin_unlock_bh(&conn->nopin_timer_lock);
                return;
        }
        conn->nopin_timer_flags |= ISCSI_TF_STOP;
        spin_unlock_bh(&conn->nopin_timer_lock);

        del_timer_sync(&conn->nopin_timer);

        spin_lock_bh(&conn->nopin_timer_lock);
        conn->nopin_timer_flags &= ~ISCSI_TF_RUNNING;
        spin_unlock_bh(&conn->nopin_timer_lock);
}

int iscsit_send_tx_data(
        struct iscsi_cmd *cmd,
        struct iscsi_conn *conn,
        int use_misc)
{
        int tx_sent, tx_size;
        u32 iov_count;
        struct kvec *iov;

send_data:
        tx_size = cmd->tx_size;

        if (!use_misc) {
                iov = &cmd->iov_data[0];
                iov_count = cmd->iov_data_count;
        } else {
                iov = &cmd->iov_misc[0];
                iov_count = cmd->iov_misc_count;
        }

        tx_sent = tx_data(conn, &iov[0], iov_count, tx_size);
        if (tx_size != tx_sent) {
                if (tx_sent == -EAGAIN) {
                        pr_err("tx_data() returned -EAGAIN\n");
                        goto send_data;
                } else
                        return -1;
        }
        cmd->tx_size = 0;

        return 0;
}

int iscsit_fe_sendpage_sg(
        struct iscsi_cmd *cmd,
        struct iscsi_conn *conn)
{
        struct scatterlist *sg = cmd->first_data_sg;
        struct kvec iov;
        u32 tx_hdr_size, data_len;
        u32 offset = cmd->first_data_sg_off;
        int tx_sent, iov_off;

send_hdr:
        tx_hdr_size = ISCSI_HDR_LEN;
        if (conn->conn_ops->HeaderDigest)
                tx_hdr_size += ISCSI_CRC_LEN;

        iov.iov_base = cmd->pdu;
        iov.iov_len = tx_hdr_size;

        tx_sent = tx_data(conn, &iov, 1, tx_hdr_size);
        if (tx_hdr_size != tx_sent) {
                if (tx_sent == -EAGAIN) {
                        pr_err("tx_data() returned -EAGAIN\n");
                        goto send_hdr;
                }
                return -1;
        }

        data_len = cmd->tx_size - tx_hdr_size - cmd->padding;
        /*
         * Set iov_off used by padding and data digest tx_data() calls below
         * in order to determine proper offset into cmd->iov_data[]
         */
        if (conn->conn_ops->DataDigest) {
                data_len -= ISCSI_CRC_LEN;
                if (cmd->padding)
                        iov_off = (cmd->iov_data_count - 2);
                else
                        iov_off = (cmd->iov_data_count - 1);
        } else {
                iov_off = (cmd->iov_data_count - 1);
        }
        /*
         * Perform sendpage() for each page in the scatterlist
         */
        while (data_len) {
                u32 space = (sg->length - offset);
                u32 sub_len = min_t(u32, data_len, space);
send_pg:
                tx_sent = conn->sock->ops->sendpage(conn->sock,
                                        sg_page(sg), sg->offset + offset, sub_len, 0);
                if (tx_sent != sub_len) {
                        if (tx_sent == -EAGAIN) {
                                pr_err("tcp_sendpage() returned"
                                                " -EAGAIN\n");
                                goto send_pg;
                        }

                        pr_err("tcp_sendpage() failure: %d\n",
                                        tx_sent);
                        return -1;
                }

                data_len -= sub_len;
                offset = 0;
                sg = sg_next(sg);
        }

send_padding:
        if (cmd->padding) {
                struct kvec *iov_p = &cmd->iov_data[iov_off++];

                tx_sent = tx_data(conn, iov_p, 1, cmd->padding);
                if (cmd->padding != tx_sent) {
                        if (tx_sent == -EAGAIN) {
                                pr_err("tx_data() returned -EAGAIN\n");
                                goto send_padding;
                        }
                        return -1;
                }
        }

send_datacrc:
        if (conn->conn_ops->DataDigest) {
                struct kvec *iov_d = &cmd->iov_data[iov_off];

                tx_sent = tx_data(conn, iov_d, 1, ISCSI_CRC_LEN);
                if (ISCSI_CRC_LEN != tx_sent) {
                        if (tx_sent == -EAGAIN) {
                                pr_err("tx_data() returned -EAGAIN\n");
                                goto send_datacrc;
                        }
                        return -1;
                }
        }

        return 0;
}

/*
 *      This function is used for mainly sending a ISCSI_TARG_LOGIN_RSP PDU
 *      back to the Initiator when an expection condition occurs with the
 *      errors set in status_class and status_detail.
 *
 *      Parameters:     iSCSI Connection, Status Class, Status Detail.
 *      Returns:        0 on success, -1 on error.
 */
int iscsit_tx_login_rsp(struct iscsi_conn *conn, u8 status_class, u8 status_detail)
{
        struct iscsi_login_rsp *hdr;
        struct iscsi_login *login = conn->conn_login;

        login->login_failed = 1;
        iscsit_collect_login_stats(conn, status_class, status_detail);

        hdr     = (struct iscsi_login_rsp *)&login->rsp[0];
        hdr->opcode             = ISCSI_OP_LOGIN_RSP;
        hdr->status_class       = status_class;
        hdr->status_detail      = status_detail;
        hdr->itt                = conn->login_itt;

        return conn->conn_transport->iscsit_put_login_tx(conn, login, 0);
}

void iscsit_print_session_params(struct iscsi_session *sess)
{
        struct iscsi_conn *conn;

        pr_debug("-----------------------------[Session Params for"
                " SID: %u]-----------------------------\n", sess->sid);
        spin_lock_bh(&sess->conn_lock);
        list_for_each_entry(conn, &sess->sess_conn_list, conn_list)
                iscsi_dump_conn_ops(conn->conn_ops);
        spin_unlock_bh(&sess->conn_lock);

        iscsi_dump_sess_ops(sess->sess_ops);
}

static int iscsit_do_rx_data(
        struct iscsi_conn *conn,
        struct iscsi_data_count *count)
{
        int data = count->data_length, rx_loop = 0, total_rx = 0, iov_len;
        struct kvec *iov_p;
        struct msghdr msg;

        if (!conn || !conn->sock || !conn->conn_ops)
                return -1;

        memset(&msg, 0, sizeof(struct msghdr));

        iov_p = count->iov;
        iov_len = count->iov_count;

        while (total_rx < data) {
                rx_loop = kernel_recvmsg(conn->sock, &msg, iov_p, iov_len,
                                        (data - total_rx), MSG_WAITALL);
                if (rx_loop <= 0) {
                        pr_debug("rx_loop: %d total_rx: %d\n",
                                rx_loop, total_rx);
                        return rx_loop;
                }
                total_rx += rx_loop;
                pr_debug("rx_loop: %d, total_rx: %d, data: %d\n",
                                rx_loop, total_rx, data);
        }

        return total_rx;
}

static int iscsit_do_tx_data(
        struct iscsi_conn *conn,
        struct iscsi_data_count *count)
{
        int data = count->data_length, total_tx = 0, tx_loop = 0, iov_len;
        struct kvec *iov_p;
        struct msghdr msg;

        if (!conn || !conn->sock || !conn->conn_ops)
                return -1;

        if (data <= 0) {
                pr_err("Data length is: %d\n", data);
                return -1;
        }

        memset(&msg, 0, sizeof(struct msghdr));

        iov_p = count->iov;
        iov_len = count->iov_count;

        while (total_tx < data) {
                tx_loop = kernel_sendmsg(conn->sock, &msg, iov_p, iov_len,
                                        (data - total_tx));
                if (tx_loop <= 0) {
                        pr_debug("tx_loop: %d total_tx %d\n",
                                tx_loop, total_tx);
                        return tx_loop;
                }
                total_tx += tx_loop;
                pr_debug("tx_loop: %d, total_tx: %d, data: %d\n",
                                        tx_loop, total_tx, data);
        }

        return total_tx;
}

int rx_data(
        struct iscsi_conn *conn,
        struct kvec *iov,
        int iov_count,
        int data)
{
        struct iscsi_data_count c;

        if (!conn || !conn->sock || !conn->conn_ops)
                return -1;

        memset(&c, 0, sizeof(struct iscsi_data_count));
        c.iov = iov;
        c.iov_count = iov_count;
        c.data_length = data;
        c.type = ISCSI_RX_DATA;

        return iscsit_do_rx_data(conn, &c);
}

int tx_data(
        struct iscsi_conn *conn,
        struct kvec *iov,
        int iov_count,
        int data)
{
        struct iscsi_data_count c;

        if (!conn || !conn->sock || !conn->conn_ops)
                return -1;

        memset(&c, 0, sizeof(struct iscsi_data_count));
        c.iov = iov;
        c.iov_count = iov_count;
        c.data_length = data;
        c.type = ISCSI_TX_DATA;

        return iscsit_do_tx_data(conn, &c);
}

void iscsit_collect_login_stats(
        struct iscsi_conn *conn,
        u8 status_class,
        u8 status_detail)
{
        struct iscsi_param *intrname = NULL;
        struct iscsi_tiqn *tiqn;
        struct iscsi_login_stats *ls;

        tiqn = iscsit_snmp_get_tiqn(conn);
        if (!tiqn)
                return;

        ls = &tiqn->login_stats;

        spin_lock(&ls->lock);
        if (!strcmp(conn->login_ip, ls->last_intr_fail_ip_addr) &&
            ((get_jiffies_64() - ls->last_fail_time) < 10)) {
                /* We already have the failure info for this login */
                spin_unlock(&ls->lock);
                return;
        }

        if (status_class == ISCSI_STATUS_CLS_SUCCESS)
                ls->accepts++;
        else if (status_class == ISCSI_STATUS_CLS_REDIRECT) {
                ls->redirects++;
                ls->last_fail_type = ISCSI_LOGIN_FAIL_REDIRECT;
        } else if ((status_class == ISCSI_STATUS_CLS_INITIATOR_ERR)  &&
                 (status_detail == ISCSI_LOGIN_STATUS_AUTH_FAILED)) {
                ls->authenticate_fails++;
                ls->last_fail_type =  ISCSI_LOGIN_FAIL_AUTHENTICATE;
        } else if ((status_class == ISCSI_STATUS_CLS_INITIATOR_ERR)  &&
                 (status_detail == ISCSI_LOGIN_STATUS_TGT_FORBIDDEN)) {
                ls->authorize_fails++;
                ls->last_fail_type = ISCSI_LOGIN_FAIL_AUTHORIZE;
        } else if ((status_class == ISCSI_STATUS_CLS_INITIATOR_ERR) &&
                 (status_detail == ISCSI_LOGIN_STATUS_INIT_ERR)) {
                ls->negotiate_fails++;
                ls->last_fail_type = ISCSI_LOGIN_FAIL_NEGOTIATE;
        } else {
                ls->other_fails++;
                ls->last_fail_type = ISCSI_LOGIN_FAIL_OTHER;
        }

        /* Save initiator name, ip address and time, if it is a failed login */
        if (status_class != ISCSI_STATUS_CLS_SUCCESS) {
                if (conn->param_list)
                        intrname = iscsi_find_param_from_key(INITIATORNAME,
                                                             conn->param_list);
                strcpy(ls->last_intr_fail_name,
                       (intrname ? intrname->value : "Unknown"));

                ls->last_intr_fail_ip_family = conn->login_family;

                snprintf(ls->last_intr_fail_ip_addr, IPV6_ADDRESS_SPACE,
                                "%s", conn->login_ip);
                ls->last_fail_time = get_jiffies_64();
        }

        spin_unlock(&ls->lock);
}

struct iscsi_tiqn *iscsit_snmp_get_tiqn(struct iscsi_conn *conn)
{
        struct iscsi_portal_group *tpg;

        if (!conn || !conn->sess)
                return NULL;

        tpg = conn->sess->tpg;
        if (!tpg)
                return NULL;

        if (!tpg->tpg_tiqn)
                return NULL;

        return tpg->tpg_tiqn;
}