1. 根目录:
2. drivers
3. target
4. iscsi
5. 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 "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;

	cmd = kmem_cache_zalloc(lio_cmd_cache, 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_list);
	INIT_LIST_HEAD(&cmd->datain_list);
	INIT_LIST_HEAD(&cmd->cmd_r2t_list);
	init_completion(&cmd->reject_comp);
	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;
}

/*
 * Called from iscsi_handle_scsi_cmd()
 */
struct iscsi_cmd *iscsit_allocate_se_cmd(
	struct iscsi_conn *conn,
	u32 data_length,
	int data_direction,
	int iscsi_task_attr)
{
	struct iscsi_cmd *cmd;
	struct se_cmd *se_cmd;
	int sam_task_attr;

	cmd = iscsit_allocate_cmd(conn, GFP_KERNEL);
	if (!cmd)
		return NULL;

	cmd->data_direction = data_direction;
	cmd->data_length = data_length;
	/*
	 * Figure out the SAM Task Attribute for the incoming SCSI CDB
	 */
	if ((iscsi_task_attr == ISCSI_ATTR_UNTAGGED) ||
	    (iscsi_task_attr == ISCSI_ATTR_SIMPLE))
		sam_task_attr = MSG_SIMPLE_TAG;
	else if (iscsi_task_attr == ISCSI_ATTR_ORDERED)
		sam_task_attr = MSG_ORDERED_TAG;
	else if (iscsi_task_attr == ISCSI_ATTR_HEAD_OF_QUEUE)
		sam_task_attr = MSG_HEAD_TAG;
	else if (iscsi_task_attr == ISCSI_ATTR_ACA)
		sam_task_attr = MSG_ACA_TAG;
	else {
		pr_debug("Unknown iSCSI Task Attribute: 0x%02x, using"
			" MSG_SIMPLE_TAG\n", iscsi_task_attr);
		sam_task_attr = MSG_SIMPLE_TAG;
	}

	se_cmd = &cmd->se_cmd;
	/*
	 * Initialize struct se_cmd descriptor from target_core_mod infrastructure
	 */
	transport_init_se_cmd(se_cmd, &lio_target_fabric_configfs->tf_ops,
			conn->sess->se_sess, data_length, data_direction,
			sam_task_attr, &cmd->sense_buffer[0]);
	return cmd;
}

struct iscsi_cmd *iscsit_allocate_se_cmd_for_tmr(
	struct iscsi_conn *conn,
	u8 function)
{
	struct iscsi_cmd *cmd;
	struct se_cmd *se_cmd;
	int rc;
	u8 tcm_function;

	cmd = iscsit_allocate_cmd(conn, GFP_KERNEL);
	if (!cmd)
		return NULL;

	cmd->data_direction = DMA_NONE;

	cmd->tmr_req = kzalloc(sizeof(struct iscsi_tmr_req), GFP_KERNEL);
	if (!cmd->tmr_req) {
		pr_err("Unable to allocate memory for"
			" Task Management command!\n");
		goto out;
	}
	/*
	 * TASK_REASSIGN for ERL=2 / connection stays inside of
	 * LIO-Target $FABRIC_MOD
	 */
	if (function == ISCSI_TM_FUNC_TASK_REASSIGN)
		return cmd;

	se_cmd = &cmd->se_cmd;
	/*
	 * Initialize struct se_cmd descriptor from target_core_mod infrastructure
	 */
	transport_init_se_cmd(se_cmd, &lio_target_fabric_configfs->tf_ops,
				conn->sess->se_sess, 0, DMA_NONE,
				MSG_SIMPLE_TAG, &cmd->sense_buffer[0]);

	switch (function) {
	case ISCSI_TM_FUNC_ABORT_TASK:
		tcm_function = TMR_ABORT_TASK;
		break;
	case ISCSI_TM_FUNC_ABORT_TASK_SET:
		tcm_function = TMR_ABORT_TASK_SET;
		break;
	case ISCSI_TM_FUNC_CLEAR_ACA:
		tcm_function = TMR_CLEAR_ACA;
		break;
	case ISCSI_TM_FUNC_CLEAR_TASK_SET:
		tcm_function = TMR_CLEAR_TASK_SET;
		break;
	case ISCSI_TM_FUNC_LOGICAL_UNIT_RESET:
		tcm_function = TMR_LUN_RESET;
		break;
	case ISCSI_TM_FUNC_TARGET_WARM_RESET:
		tcm_function = TMR_TARGET_WARM_RESET;
		break;
	case ISCSI_TM_FUNC_TARGET_COLD_RESET:
		tcm_function = TMR_TARGET_COLD_RESET;
		break;
	default:
		pr_err("Unknown iSCSI TMR Function:"
			" 0x%02x\n", function);
		goto out;
	}

	rc = core_tmr_alloc_req(se_cmd, cmd->tmr_req, tcm_function, GFP_KERNEL);
	if (rc < 0)
		goto out;

	cmd->tmr_req->se_tmr_req = se_cmd->se_tmr_req;

	return cmd;
out:
	iscsit_release_cmd(cmd);
	return NULL;
}

int iscsit_decide_list_to_build(
	struct iscsi_cmd *cmd,
	u32 immediate_data_length)
{
	struct iscsi_build_list bl;
	struct iscsi_conn *conn = cmd->conn;
	struct iscsi_session *sess = conn->sess;
	struct iscsi_node_attrib *na;

	if (sess->sess_ops->DataSequenceInOrder &&
	    sess->sess_ops->DataPDUInOrder)
		return 0;

	if (cmd->data_direction == DMA_NONE)
		return 0;

	na = iscsit_tpg_get_node_attrib(sess);
	memset(&bl, 0, sizeof(struct iscsi_build_list));

	if (cmd->data_direction == DMA_FROM_DEVICE) {
		bl.data_direction = ISCSI_PDU_READ;
		bl.type = PDULIST_NORMAL;
		if (na->random_datain_pdu_offsets)
			bl.randomize |= RANDOM_DATAIN_PDU_OFFSETS;
		if (na->random_datain_seq_offsets)
			bl.randomize |= RANDOM_DATAIN_SEQ_OFFSETS;
	} else {
		bl.data_direction = ISCSI_PDU_WRITE;
		bl.immediate_data_length = immediate_data_length;
		if (na->random_r2t_offsets)
			bl.randomize |= RANDOM_R2T_OFFSETS;

		if (!cmd->immediate_data && !cmd->unsolicited_data)
			bl.type = PDULIST_NORMAL;
		else if (cmd->immediate_data && !cmd->unsolicited_data)
			bl.type = PDULIST_IMMEDIATE;
		else if (!cmd->immediate_data && cmd->unsolicited_data)
			bl.type = PDULIST_UNSOLICITED;
		else if (cmd->immediate_data && cmd->unsolicited_data)
			bl.type = PDULIST_IMMEDIATE_AND_UNSOLICITED;
	}

	return iscsit_do_build_list(cmd, &bl);
}

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,
	u32 cmdsn)
{
	int ret;
	int cmdsn_ret;

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

	cmdsn_ret = iscsit_check_received_cmdsn(conn->sess, 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);
		break;
	case CMDSN_HIGHER_THAN_EXP:
		ret = iscsit_handle_ooo_cmdsn(conn->sess, cmd, cmdsn);
		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:
		ret = cmdsn_ret;
		break;
	}
	mutex_unlock(&conn->sess->cmdsn_mutex);

	return ret;
}

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->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->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,
	u32 init_task_tag)
{
	struct iscsi_cmd *cmd;

	spin_lock_bh(&conn->cmd_lock);
	list_for_each_entry(cmd, &conn->conn_cmd_list, i_list) {
		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,
	u32 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_list) {
		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_list) {
		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,
	u32 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_list) {
			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_list) {
			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;
	}
	list_for_each_entry(qr, &conn->immed_queue_list, qr_list)
		break;

	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;
	}

	list_for_each_entry(qr, &conn->response_queue_list, qr_list)
		break;

	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)
{
	struct iscsi_conn *conn = cmd->conn;
	int i;

	iscsit_free_r2ts_from_list(cmd);
	iscsit_free_all_datain_reqs(cmd);

	kfree(cmd->buf_ptr);
	kfree(cmd->pdu_list);
	kfree(cmd->seq_list);
	kfree(cmd->tmr_req);
	kfree(cmd->iov_data);

	for (i = 0; i < cmd->t_mem_sg_nents; i++)
		__free_page(sg_page(&cmd->t_mem_sg[i]));

	kfree(cmd->t_mem_sg);

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

	kmem_cache_free(lio_cmd_cache, cmd);
}

void iscsit_free_cmd(struct iscsi_cmd *cmd)
{
	/*
	 * Determine if a struct se_cmd is assoicated with
	 * this struct iscsi_cmd.
	 */
	switch (cmd->iscsi_opcode) {
	case ISCSI_OP_SCSI_CMD:
	case ISCSI_OP_SCSI_TMFUNC:
		transport_generic_free_cmd(&cmd->se_cmd, 1);
		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) {
			transport_generic_free_cmd(&cmd->se_cmd, 1);
			break;
		}
		/* Fall-through */
	default:
		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 = 0xFFFFFFFF;
	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_list, &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)
{
	u8 iscsi_hdr[ISCSI_HDR_LEN];
	int err;
	struct kvec iov;
	struct iscsi_login_rsp *hdr;

	iscsit_collect_login_stats(conn, status_class, status_detail);

	memset(&iov, 0, sizeof(struct kvec));
	memset(&iscsi_hdr, 0x0, ISCSI_HDR_LEN);

	hdr	= (struct iscsi_login_rsp *)&iscsi_hdr;
	hdr->opcode		= ISCSI_OP_LOGIN_RSP;
	hdr->status_class	= status_class;
	hdr->status_detail	= status_detail;
	hdr->itt		= cpu_to_be32(conn->login_itt);

	iov.iov_base		= &iscsi_hdr;
	iov.iov_len		= ISCSI_HDR_LEN;

	PRINT_BUFF(iscsi_hdr, ISCSI_HDR_LEN);

	err = tx_data(conn, &iov, 1, ISCSI_HDR_LEN);
	if (err != ISCSI_HDR_LEN) {
		pr_err("tx_data returned less than expected\n");
		return -1;
	}

	return 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->sock->sk->sk_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;
}