/*******************************************************************************
 * This file contains main functions related to the iSCSI Target Core Driver.
 *
 * \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/string.h>
#include <linux/kthread.h>
#include <linux/crypto.h>
#include <linux/completion.h>
#include <linux/module.h>
#include <linux/idr.h>
#include <asm/unaligned.h>
#include <scsi/scsi_device.h>
#include <scsi/iscsi_proto.h>
#include <scsi/scsi_tcq.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_tq.h"
#include "iscsi_target_configfs.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_login.h"
#include "iscsi_target_tmr.h"
#include "iscsi_target_tpg.h"
#include "iscsi_target_util.h"
#include "iscsi_target.h"
#include "iscsi_target_device.h"
#include "iscsi_target_stat.h"

static LIST_HEAD(g_tiqn_list);
static LIST_HEAD(g_np_list);
static DEFINE_SPINLOCK(tiqn_lock);
static DEFINE_SPINLOCK(np_lock);

static struct idr tiqn_idr;
struct idr sess_idr;
struct mutex auth_id_lock;
spinlock_t sess_idr_lock;

struct iscsit_global *iscsit_global;

struct kmem_cache *lio_cmd_cache;
struct kmem_cache *lio_qr_cache;
struct kmem_cache *lio_dr_cache;
struct kmem_cache *lio_ooo_cache;
struct kmem_cache *lio_r2t_cache;

static int iscsit_handle_immediate_data(struct iscsi_cmd *,
                        unsigned char *buf, u32);
static int iscsit_logout_post_handler(struct iscsi_cmd *, struct iscsi_conn *);

struct iscsi_tiqn *iscsit_get_tiqn_for_login(unsigned char *buf)
{
        struct iscsi_tiqn *tiqn = NULL;

        spin_lock(&tiqn_lock);
        list_for_each_entry(tiqn, &g_tiqn_list, tiqn_list) {
                if (!strcmp(tiqn->tiqn, buf)) {

                        spin_lock(&tiqn->tiqn_state_lock);
                        if (tiqn->tiqn_state == TIQN_STATE_ACTIVE) {
                                tiqn->tiqn_access_count++;
                                spin_unlock(&tiqn->tiqn_state_lock);
                                spin_unlock(&tiqn_lock);
                                return tiqn;
                        }
                        spin_unlock(&tiqn->tiqn_state_lock);
                }
        }
        spin_unlock(&tiqn_lock);

        return NULL;
}

static int iscsit_set_tiqn_shutdown(struct iscsi_tiqn *tiqn)
{
        spin_lock(&tiqn->tiqn_state_lock);
        if (tiqn->tiqn_state == TIQN_STATE_ACTIVE) {
                tiqn->tiqn_state = TIQN_STATE_SHUTDOWN;
                spin_unlock(&tiqn->tiqn_state_lock);
                return 0;
        }
        spin_unlock(&tiqn->tiqn_state_lock);

        return -1;
}

void iscsit_put_tiqn_for_login(struct iscsi_tiqn *tiqn)
{
        spin_lock(&tiqn->tiqn_state_lock);
        tiqn->tiqn_access_count--;
        spin_unlock(&tiqn->tiqn_state_lock);
}

/*
 * Note that IQN formatting is expected to be done in userspace, and
 * no explict IQN format checks are done here.
 */
struct iscsi_tiqn *iscsit_add_tiqn(unsigned char *buf)
{
        struct iscsi_tiqn *tiqn = NULL;
        int ret;

        if (strlen(buf) >= ISCSI_IQN_LEN) {
                pr_err("Target IQN exceeds %d bytes\n",
                                ISCSI_IQN_LEN);
                return ERR_PTR(-EINVAL);
        }

        tiqn = kzalloc(sizeof(struct iscsi_tiqn), GFP_KERNEL);
        if (!tiqn) {
                pr_err("Unable to allocate struct iscsi_tiqn\n");
                return ERR_PTR(-ENOMEM);
        }

        sprintf(tiqn->tiqn, "%s", buf);
        INIT_LIST_HEAD(&tiqn->tiqn_list);
        INIT_LIST_HEAD(&tiqn->tiqn_tpg_list);
        spin_lock_init(&tiqn->tiqn_state_lock);
        spin_lock_init(&tiqn->tiqn_tpg_lock);
        spin_lock_init(&tiqn->sess_err_stats.lock);
        spin_lock_init(&tiqn->login_stats.lock);
        spin_lock_init(&tiqn->logout_stats.lock);

        if (!idr_pre_get(&tiqn_idr, GFP_KERNEL)) {
                pr_err("idr_pre_get() for tiqn_idr failed\n");
                kfree(tiqn);
                return ERR_PTR(-ENOMEM);
        }
        tiqn->tiqn_state = TIQN_STATE_ACTIVE;

        spin_lock(&tiqn_lock);
        ret = idr_get_new(&tiqn_idr, NULL, &tiqn->tiqn_index);
        if (ret < 0) {
                pr_err("idr_get_new() failed for tiqn->tiqn_index\n");
                spin_unlock(&tiqn_lock);
                kfree(tiqn);
                return ERR_PTR(ret);
        }
        list_add_tail(&tiqn->tiqn_list, &g_tiqn_list);
        spin_unlock(&tiqn_lock);

        pr_debug("CORE[0] - Added iSCSI Target IQN: %s\n", tiqn->tiqn);

        return tiqn;

}

static void iscsit_wait_for_tiqn(struct iscsi_tiqn *tiqn)
{
        /*
         * Wait for accesses to said struct iscsi_tiqn to end.
         */
        spin_lock(&tiqn->tiqn_state_lock);
        while (tiqn->tiqn_access_count != 0) {
                spin_unlock(&tiqn->tiqn_state_lock);
                msleep(10);
                spin_lock(&tiqn->tiqn_state_lock);
        }
        spin_unlock(&tiqn->tiqn_state_lock);
}

void iscsit_del_tiqn(struct iscsi_tiqn *tiqn)
{
        /*
         * iscsit_set_tiqn_shutdown sets tiqn->tiqn_state = TIQN_STATE_SHUTDOWN
         * while holding tiqn->tiqn_state_lock.  This means that all subsequent
         * attempts to access this struct iscsi_tiqn will fail from both transport
         * fabric and control code paths.
         */
        if (iscsit_set_tiqn_shutdown(tiqn) < 0) {
                pr_err("iscsit_set_tiqn_shutdown() failed\n");
                return;
        }

        iscsit_wait_for_tiqn(tiqn);

        spin_lock(&tiqn_lock);
        list_del(&tiqn->tiqn_list);
        idr_remove(&tiqn_idr, tiqn->tiqn_index);
        spin_unlock(&tiqn_lock);

        pr_debug("CORE[0] - Deleted iSCSI Target IQN: %s\n",
                        tiqn->tiqn);
        kfree(tiqn);
}

int iscsit_access_np(struct iscsi_np *np, struct iscsi_portal_group *tpg)
{
        int ret;
        /*
         * Determine if the network portal is accepting storage traffic.
         */
        spin_lock_bh(&np->np_thread_lock);
        if (np->np_thread_state != ISCSI_NP_THREAD_ACTIVE) {
                spin_unlock_bh(&np->np_thread_lock);
                return -1;
        }
        if (np->np_login_tpg) {
                pr_err("np->np_login_tpg() is not NULL!\n");
                spin_unlock_bh(&np->np_thread_lock);
                return -1;
        }
        spin_unlock_bh(&np->np_thread_lock);
        /*
         * Determine if the portal group is accepting storage traffic.
         */
        spin_lock_bh(&tpg->tpg_state_lock);
        if (tpg->tpg_state != TPG_STATE_ACTIVE) {
                spin_unlock_bh(&tpg->tpg_state_lock);
                return -1;
        }
        spin_unlock_bh(&tpg->tpg_state_lock);

        /*
         * Here we serialize access across the TIQN+TPG Tuple.
         */
        ret = mutex_lock_interruptible(&tpg->np_login_lock);
        if ((ret != 0) || signal_pending(current))
                return -1;

        spin_lock_bh(&np->np_thread_lock);
        np->np_login_tpg = tpg;
        spin_unlock_bh(&np->np_thread_lock);

        return 0;
}

int iscsit_deaccess_np(struct iscsi_np *np, struct iscsi_portal_group *tpg)
{
        struct iscsi_tiqn *tiqn = tpg->tpg_tiqn;

        spin_lock_bh(&np->np_thread_lock);
        np->np_login_tpg = NULL;
        spin_unlock_bh(&np->np_thread_lock);

        mutex_unlock(&tpg->np_login_lock);

        if (tiqn)
                iscsit_put_tiqn_for_login(tiqn);

        return 0;
}

static struct iscsi_np *iscsit_get_np(
        struct __kernel_sockaddr_storage *sockaddr,
        int network_transport)
{
        struct sockaddr_in *sock_in, *sock_in_e;
        struct sockaddr_in6 *sock_in6, *sock_in6_e;
        struct iscsi_np *np;
        int ip_match = 0;
        u16 port;

        spin_lock_bh(&np_lock);
        list_for_each_entry(np, &g_np_list, np_list) {
                spin_lock(&np->np_thread_lock);
                if (np->np_thread_state != ISCSI_NP_THREAD_ACTIVE) {
                        spin_unlock(&np->np_thread_lock);
                        continue;
                }

                if (sockaddr->ss_family == AF_INET6) {
                        sock_in6 = (struct sockaddr_in6 *)sockaddr;
                        sock_in6_e = (struct sockaddr_in6 *)&np->np_sockaddr;

                        if (!memcmp(&sock_in6->sin6_addr.in6_u,
                                    &sock_in6_e->sin6_addr.in6_u,
                                    sizeof(struct in6_addr)))
                                ip_match = 1;

                        port = ntohs(sock_in6->sin6_port);
                } else {
                        sock_in = (struct sockaddr_in *)sockaddr;
                        sock_in_e = (struct sockaddr_in *)&np->np_sockaddr;

                        if (sock_in->sin_addr.s_addr ==
                            sock_in_e->sin_addr.s_addr)
                                ip_match = 1;

                        port = ntohs(sock_in->sin_port);
                }

                if ((ip_match == 1) && (np->np_port == port) &&
                    (np->np_network_transport == network_transport)) {
                        /*
                         * Increment the np_exports reference count now to
                         * prevent iscsit_del_np() below from being called
                         * while iscsi_tpg_add_network_portal() is called.
                         */
                        np->np_exports++;
                        spin_unlock(&np->np_thread_lock);
                        spin_unlock_bh(&np_lock);
                        return np;
                }
                spin_unlock(&np->np_thread_lock);
        }
        spin_unlock_bh(&np_lock);

        return NULL;
}

struct iscsi_np *iscsit_add_np(
        struct __kernel_sockaddr_storage *sockaddr,
        char *ip_str,
        int network_transport)
{
        struct sockaddr_in *sock_in;
        struct sockaddr_in6 *sock_in6;
        struct iscsi_np *np;
        int ret;
        /*
         * Locate the existing struct iscsi_np if already active..
         */
        np = iscsit_get_np(sockaddr, network_transport);
        if (np)
                return np;

        np = kzalloc(sizeof(struct iscsi_np), GFP_KERNEL);
        if (!np) {
                pr_err("Unable to allocate memory for struct iscsi_np\n");
                return ERR_PTR(-ENOMEM);
        }

        np->np_flags |= NPF_IP_NETWORK;
        if (sockaddr->ss_family == AF_INET6) {
                sock_in6 = (struct sockaddr_in6 *)sockaddr;
                snprintf(np->np_ip, IPV6_ADDRESS_SPACE, "%s", ip_str);
                np->np_port = ntohs(sock_in6->sin6_port);
        } else {
                sock_in = (struct sockaddr_in *)sockaddr;
                sprintf(np->np_ip, "%s", ip_str);
                np->np_port = ntohs(sock_in->sin_port);
        }

        np->np_network_transport = network_transport;
        spin_lock_init(&np->np_thread_lock);
        init_completion(&np->np_restart_comp);
        INIT_LIST_HEAD(&np->np_list);

        ret = iscsi_target_setup_login_socket(np, sockaddr);
        if (ret != 0) {
                kfree(np);
                return ERR_PTR(ret);
        }

        np->np_thread = kthread_run(iscsi_target_login_thread, np, "iscsi_np");
        if (IS_ERR(np->np_thread)) {
                pr_err("Unable to create kthread: iscsi_np\n");
                ret = PTR_ERR(np->np_thread);
                kfree(np);
                return ERR_PTR(ret);
        }
        /*
         * Increment the np_exports reference count now to prevent
         * iscsit_del_np() below from being run while a new call to
         * iscsi_tpg_add_network_portal() for a matching iscsi_np is
         * active.  We don't need to hold np->np_thread_lock at this
         * point because iscsi_np has not been added to g_np_list yet.
         */
        np->np_exports = 1;

        spin_lock_bh(&np_lock);
        list_add_tail(&np->np_list, &g_np_list);
        spin_unlock_bh(&np_lock);

        pr_debug("CORE[0] - Added Network Portal: %s:%hu on %s\n",
                np->np_ip, np->np_port, (np->np_network_transport == ISCSI_TCP) ?
                "TCP" : "SCTP");

        return np;
}

int iscsit_reset_np_thread(
        struct iscsi_np *np,
        struct iscsi_tpg_np *tpg_np,
        struct iscsi_portal_group *tpg)
{
        spin_lock_bh(&np->np_thread_lock);
        if (tpg && tpg_np) {
                /*
                 * The reset operation need only be performed when the
                 * passed struct iscsi_portal_group has a login in progress
                 * to one of the network portals.
                 */
                if (tpg_np->tpg_np->np_login_tpg != tpg) {
                        spin_unlock_bh(&np->np_thread_lock);
                        return 0;
                }
        }
        if (np->np_thread_state == ISCSI_NP_THREAD_INACTIVE) {
                spin_unlock_bh(&np->np_thread_lock);
                return 0;
        }
        np->np_thread_state = ISCSI_NP_THREAD_RESET;

        if (np->np_thread) {
                spin_unlock_bh(&np->np_thread_lock);
                send_sig(SIGINT, np->np_thread, 1);
                wait_for_completion(&np->np_restart_comp);
                spin_lock_bh(&np->np_thread_lock);
        }
        spin_unlock_bh(&np->np_thread_lock);

        return 0;
}

static int iscsit_del_np_comm(struct iscsi_np *np)
{
        if (np->np_socket)
                sock_release(np->np_socket);
        return 0;
}

int iscsit_del_np(struct iscsi_np *np)
{
        spin_lock_bh(&np->np_thread_lock);
        np->np_exports--;
        if (np->np_exports) {
                spin_unlock_bh(&np->np_thread_lock);
                return 0;
        }
        np->np_thread_state = ISCSI_NP_THREAD_SHUTDOWN;
        spin_unlock_bh(&np->np_thread_lock);

        if (np->np_thread) {
                /*
                 * We need to send the signal to wakeup Linux/Net
                 * which may be sleeping in sock_accept()..
                 */
                send_sig(SIGINT, np->np_thread, 1);
                kthread_stop(np->np_thread);
        }
        iscsit_del_np_comm(np);

        spin_lock_bh(&np_lock);
        list_del(&np->np_list);
        spin_unlock_bh(&np_lock);

        pr_debug("CORE[0] - Removed Network Portal: %s:%hu on %s\n",
                np->np_ip, np->np_port, (np->np_network_transport == ISCSI_TCP) ?
                "TCP" : "SCTP");

        kfree(np);
        return 0;
}

static int __init iscsi_target_init_module(void)
{
        int ret = 0;

        pr_debug("iSCSI-Target "ISCSIT_VERSION"\n");

        iscsit_global = kzalloc(sizeof(struct iscsit_global), GFP_KERNEL);
        if (!iscsit_global) {
                pr_err("Unable to allocate memory for iscsit_global\n");
                return -1;
        }
        mutex_init(&auth_id_lock);
        spin_lock_init(&sess_idr_lock);
        idr_init(&tiqn_idr);
        idr_init(&sess_idr);

        ret = iscsi_target_register_configfs();
        if (ret < 0)
                goto out;

        ret = iscsi_thread_set_init();
        if (ret < 0)
                goto configfs_out;

        if (iscsi_allocate_thread_sets(TARGET_THREAD_SET_COUNT) !=
                        TARGET_THREAD_SET_COUNT) {
                pr_err("iscsi_allocate_thread_sets() returned"
                        " unexpected value!\n");
                goto ts_out1;
        }

        lio_cmd_cache = kmem_cache_create("lio_cmd_cache",
                        sizeof(struct iscsi_cmd), __alignof__(struct iscsi_cmd),
                        0, NULL);
        if (!lio_cmd_cache) {
                pr_err("Unable to kmem_cache_create() for"
                                " lio_cmd_cache\n");
                goto ts_out2;
        }

        lio_qr_cache = kmem_cache_create("lio_qr_cache",
                        sizeof(struct iscsi_queue_req),
                        __alignof__(struct iscsi_queue_req), 0, NULL);
        if (!lio_qr_cache) {
                pr_err("nable to kmem_cache_create() for"
                                " lio_qr_cache\n");
                goto cmd_out;
        }

        lio_dr_cache = kmem_cache_create("lio_dr_cache",
                        sizeof(struct iscsi_datain_req),
                        __alignof__(struct iscsi_datain_req), 0, NULL);
        if (!lio_dr_cache) {
                pr_err("Unable to kmem_cache_create() for"
                                " lio_dr_cache\n");
                goto qr_out;
        }

        lio_ooo_cache = kmem_cache_create("lio_ooo_cache",
                        sizeof(struct iscsi_ooo_cmdsn),
                        __alignof__(struct iscsi_ooo_cmdsn), 0, NULL);
        if (!lio_ooo_cache) {
                pr_err("Unable to kmem_cache_create() for"
                                " lio_ooo_cache\n");
                goto dr_out;
        }

        lio_r2t_cache = kmem_cache_create("lio_r2t_cache",
                        sizeof(struct iscsi_r2t), __alignof__(struct iscsi_r2t),
                        0, NULL);
        if (!lio_r2t_cache) {
                pr_err("Unable to kmem_cache_create() for"
                                " lio_r2t_cache\n");
                goto ooo_out;
        }

        if (iscsit_load_discovery_tpg() < 0)
                goto r2t_out;

        return ret;
r2t_out:
        kmem_cache_destroy(lio_r2t_cache);
ooo_out:
        kmem_cache_destroy(lio_ooo_cache);
dr_out:
        kmem_cache_destroy(lio_dr_cache);
qr_out:
        kmem_cache_destroy(lio_qr_cache);
cmd_out:
        kmem_cache_destroy(lio_cmd_cache);
ts_out2:
        iscsi_deallocate_thread_sets();
ts_out1:
        iscsi_thread_set_free();
configfs_out:
        iscsi_target_deregister_configfs();
out:
        kfree(iscsit_global);
        return -ENOMEM;
}

static void __exit iscsi_target_cleanup_module(void)
{
        iscsi_deallocate_thread_sets();
        iscsi_thread_set_free();
        iscsit_release_discovery_tpg();
        kmem_cache_destroy(lio_cmd_cache);
        kmem_cache_destroy(lio_qr_cache);
        kmem_cache_destroy(lio_dr_cache);
        kmem_cache_destroy(lio_ooo_cache);
        kmem_cache_destroy(lio_r2t_cache);

        iscsi_target_deregister_configfs();

        kfree(iscsit_global);
}

static int iscsit_add_reject(
        u8 reason,
        int fail_conn,
        unsigned char *buf,
        struct iscsi_conn *conn)
{
        struct iscsi_cmd *cmd;
        struct iscsi_reject *hdr;
        int ret;

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

        cmd->iscsi_opcode = ISCSI_OP_REJECT;
        if (fail_conn)
                cmd->cmd_flags |= ICF_REJECT_FAIL_CONN;

        hdr     = (struct iscsi_reject *) cmd->pdu;
        hdr->reason = reason;

        cmd->buf_ptr = kmemdup(buf, ISCSI_HDR_LEN, GFP_KERNEL);
        if (!cmd->buf_ptr) {
                pr_err("Unable to allocate memory for cmd->buf_ptr\n");
                iscsit_release_cmd(cmd);
                return -1;
        }

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

        cmd->i_state = ISTATE_SEND_REJECT;
        iscsit_add_cmd_to_response_queue(cmd, conn, cmd->i_state);

        ret = wait_for_completion_interruptible(&cmd->reject_comp);
        if (ret != 0)
                return -1;

        return (!fail_conn) ? 0 : -1;
}

int iscsit_add_reject_from_cmd(
        u8 reason,
        int fail_conn,
        int add_to_conn,
        unsigned char *buf,
        struct iscsi_cmd *cmd)
{
        struct iscsi_conn *conn;
        struct iscsi_reject *hdr;
        int ret;

        if (!cmd->conn) {
                pr_err("cmd->conn is NULL for ITT: 0x%08x\n",
                                cmd->init_task_tag);
                return -1;
        }
        conn = cmd->conn;

        cmd->iscsi_opcode = ISCSI_OP_REJECT;
        if (fail_conn)
                cmd->cmd_flags |= ICF_REJECT_FAIL_CONN;

        hdr     = (struct iscsi_reject *) cmd->pdu;
        hdr->reason = reason;

        cmd->buf_ptr = kmemdup(buf, ISCSI_HDR_LEN, GFP_KERNEL);
        if (!cmd->buf_ptr) {
                pr_err("Unable to allocate memory for cmd->buf_ptr\n");
                iscsit_release_cmd(cmd);
                return -1;
        }

        if (add_to_conn) {
                spin_lock_bh(&conn->cmd_lock);
                list_add_tail(&cmd->i_conn_node, &conn->conn_cmd_list);
                spin_unlock_bh(&conn->cmd_lock);
        }

        cmd->i_state = ISTATE_SEND_REJECT;
        iscsit_add_cmd_to_response_queue(cmd, conn, cmd->i_state);

        ret = wait_for_completion_interruptible(&cmd->reject_comp);
        if (ret != 0)
                return -1;

        return (!fail_conn) ? 0 : -1;
}

/*
 * Map some portion of the allocated scatterlist to an iovec, suitable for
 * kernel sockets to copy data in/out.
 */
static int iscsit_map_iovec(
        struct iscsi_cmd *cmd,
        struct kvec *iov,
        u32 data_offset,
        u32 data_length)
{
        u32 i = 0;
        struct scatterlist *sg;
        unsigned int page_off;

        /*
         * We know each entry in t_data_sg contains a page.
         */
        sg = &cmd->se_cmd.t_data_sg[data_offset / PAGE_SIZE];
        page_off = (data_offset % PAGE_SIZE);

        cmd->first_data_sg = sg;
        cmd->first_data_sg_off = page_off;

        while (data_length) {
                u32 cur_len = min_t(u32, data_length, sg->length - page_off);

                iov[i].iov_base = kmap(sg_page(sg)) + sg->offset + page_off;
                iov[i].iov_len = cur_len;

                data_length -= cur_len;
                page_off = 0;
                sg = sg_next(sg);
                i++;
        }

        cmd->kmapped_nents = i;

        return i;
}

static void iscsit_unmap_iovec(struct iscsi_cmd *cmd)
{
        u32 i;
        struct scatterlist *sg;

        sg = cmd->first_data_sg;

        for (i = 0; i < cmd->kmapped_nents; i++)
                kunmap(sg_page(&sg[i]));
}

static void iscsit_ack_from_expstatsn(struct iscsi_conn *conn, u32 exp_statsn)
{
        struct iscsi_cmd *cmd;

        conn->exp_statsn = exp_statsn;

        spin_lock_bh(&conn->cmd_lock);
        list_for_each_entry(cmd, &conn->conn_cmd_list, i_conn_node) {
                spin_lock(&cmd->istate_lock);
                if ((cmd->i_state == ISTATE_SENT_STATUS) &&
                    (cmd->stat_sn < exp_statsn)) {
                        cmd->i_state = ISTATE_REMOVE;
                        spin_unlock(&cmd->istate_lock);
                        iscsit_add_cmd_to_immediate_queue(cmd, conn,
                                                cmd->i_state);
                        continue;
                }
                spin_unlock(&cmd->istate_lock);
        }
        spin_unlock_bh(&conn->cmd_lock);
}

static int iscsit_allocate_iovecs(struct iscsi_cmd *cmd)
{
        u32 iov_count = max(1UL, DIV_ROUND_UP(cmd->se_cmd.data_length, PAGE_SIZE));

        iov_count += ISCSI_IOV_DATA_BUFFER;

        cmd->iov_data = kzalloc(iov_count * sizeof(struct kvec), GFP_KERNEL);
        if (!cmd->iov_data) {
                pr_err("Unable to allocate cmd->iov_data\n");
                return -ENOMEM;
        }

        cmd->orig_iov_data_count = iov_count;
        return 0;
}

static int iscsit_handle_scsi_cmd(
        struct iscsi_conn *conn,
        unsigned char *buf)
{
        int     data_direction, cmdsn_ret = 0, immed_ret, ret, transport_ret;
        int     dump_immediate_data = 0, send_check_condition = 0, payload_length;
        struct iscsi_cmd        *cmd = NULL;
        struct iscsi_scsi_req *hdr;
        int iscsi_task_attr;
        int sam_task_attr;

        spin_lock_bh(&conn->sess->session_stats_lock);
        conn->sess->cmd_pdus++;
        if (conn->sess->se_sess->se_node_acl) {
                spin_lock(&conn->sess->se_sess->se_node_acl->stats_lock);
                conn->sess->se_sess->se_node_acl->num_cmds++;
                spin_unlock(&conn->sess->se_sess->se_node_acl->stats_lock);
        }
        spin_unlock_bh(&conn->sess->session_stats_lock);

        hdr                     = (struct iscsi_scsi_req *) buf;
        payload_length          = ntoh24(hdr->dlength);

        /* FIXME; Add checks for AdditionalHeaderSegment */

        if (!(hdr->flags & ISCSI_FLAG_CMD_WRITE) &&
            !(hdr->flags & ISCSI_FLAG_CMD_FINAL)) {
                pr_err("ISCSI_FLAG_CMD_WRITE & ISCSI_FLAG_CMD_FINAL"
                                " not set. Bad iSCSI Initiator.\n");
                return iscsit_add_reject(ISCSI_REASON_BOOKMARK_INVALID, 1,
                                buf, conn);
        }

        if (((hdr->flags & ISCSI_FLAG_CMD_READ) ||
             (hdr->flags & ISCSI_FLAG_CMD_WRITE)) && !hdr->data_length) {
                /*
                 * Vmware ESX v3.0 uses a modified Cisco Initiator (v3.4.2)
                 * that adds support for RESERVE/RELEASE.  There is a bug
                 * add with this new functionality that sets R/W bits when
                 * neither CDB carries any READ or WRITE datapayloads.
                 */
                if ((hdr->cdb[0] == 0x16) || (hdr->cdb[0] == 0x17)) {
                        hdr->flags &= ~ISCSI_FLAG_CMD_READ;
                        hdr->flags &= ~ISCSI_FLAG_CMD_WRITE;
                        goto done;
                }

                pr_err("ISCSI_FLAG_CMD_READ or ISCSI_FLAG_CMD_WRITE"
                        " set when Expected Data Transfer Length is 0 for"
                        " CDB: 0x%02x. Bad iSCSI Initiator.\n", hdr->cdb[0]);
                return iscsit_add_reject(ISCSI_REASON_BOOKMARK_INVALID, 1,
                                buf, conn);
        }
done:

        if (!(hdr->flags & ISCSI_FLAG_CMD_READ) &&
            !(hdr->flags & ISCSI_FLAG_CMD_WRITE) && (hdr->data_length != 0)) {
                pr_err("ISCSI_FLAG_CMD_READ and/or ISCSI_FLAG_CMD_WRITE"
                        " MUST be set if Expected Data Transfer Length is not 0."
                        " Bad iSCSI Initiator\n");
                return iscsit_add_reject(ISCSI_REASON_BOOKMARK_INVALID, 1,
                                buf, conn);
        }

        if ((hdr->flags & ISCSI_FLAG_CMD_READ) &&
            (hdr->flags & ISCSI_FLAG_CMD_WRITE)) {
                pr_err("Bidirectional operations not supported!\n");
                return iscsit_add_reject(ISCSI_REASON_BOOKMARK_INVALID, 1,
                                buf, conn);
        }

        if (hdr->opcode & ISCSI_OP_IMMEDIATE) {
                pr_err("Illegally set Immediate Bit in iSCSI Initiator"
                                " Scsi Command PDU.\n");
                return iscsit_add_reject(ISCSI_REASON_BOOKMARK_INVALID, 1,
                                buf, conn);
        }

        if (payload_length && !conn->sess->sess_ops->ImmediateData) {
                pr_err("ImmediateData=No but DataSegmentLength=%u,"
                        " protocol error.\n", payload_length);
                return iscsit_add_reject(ISCSI_REASON_PROTOCOL_ERROR, 1,
                                buf, conn);
        }

        if ((be32_to_cpu(hdr->data_length )== payload_length) &&
            (!(hdr->flags & ISCSI_FLAG_CMD_FINAL))) {
                pr_err("Expected Data Transfer Length and Length of"
                        " Immediate Data are the same, but ISCSI_FLAG_CMD_FINAL"
                        " bit is not set protocol error\n");
                return iscsit_add_reject(ISCSI_REASON_PROTOCOL_ERROR, 1,
                                buf, conn);
        }

        if (payload_length > be32_to_cpu(hdr->data_length)) {
                pr_err("DataSegmentLength: %u is greater than"
                        " EDTL: %u, protocol error.\n", payload_length,
                                hdr->data_length);
                return iscsit_add_reject(ISCSI_REASON_PROTOCOL_ERROR, 1,
                                buf, conn);
        }

        if (payload_length > conn->conn_ops->MaxXmitDataSegmentLength) {
                pr_err("DataSegmentLength: %u is greater than"
                        " MaxXmitDataSegmentLength: %u, protocol error.\n",
                        payload_length, conn->conn_ops->MaxXmitDataSegmentLength);
                return iscsit_add_reject(ISCSI_REASON_PROTOCOL_ERROR, 1,
                                buf, conn);
        }

        if (payload_length > conn->sess->sess_ops->FirstBurstLength) {
                pr_err("DataSegmentLength: %u is greater than"
                        " FirstBurstLength: %u, protocol error.\n",
                        payload_length, conn->sess->sess_ops->FirstBurstLength);
                return iscsit_add_reject(ISCSI_REASON_BOOKMARK_INVALID, 1,
                                        buf, conn);
        }

        data_direction = (hdr->flags & ISCSI_FLAG_CMD_WRITE) ? DMA_TO_DEVICE :
                         (hdr->flags & ISCSI_FLAG_CMD_READ) ? DMA_FROM_DEVICE :
                          DMA_NONE;

        cmd = iscsit_allocate_cmd(conn, GFP_KERNEL);
        if (!cmd)
                return iscsit_add_reject(ISCSI_REASON_BOOKMARK_NO_RESOURCES, 1,
                                         buf, conn);

        cmd->data_direction = data_direction;
        iscsi_task_attr = hdr->flags & ISCSI_FLAG_CMD_ATTR_MASK;
        /*
         * 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;
        }

        cmd->iscsi_opcode       = ISCSI_OP_SCSI_CMD;
        cmd->i_state            = ISTATE_NEW_CMD;
        cmd->immediate_cmd      = ((hdr->opcode & ISCSI_OP_IMMEDIATE) ? 1 : 0);
        cmd->immediate_data     = (payload_length) ? 1 : 0;
        cmd->unsolicited_data   = ((!(hdr->flags & ISCSI_FLAG_CMD_FINAL) &&
                                     (hdr->flags & ISCSI_FLAG_CMD_WRITE)) ? 1 : 0);
        if (cmd->unsolicited_data)
                cmd->cmd_flags |= ICF_NON_IMMEDIATE_UNSOLICITED_DATA;

        conn->sess->init_task_tag = cmd->init_task_tag = hdr->itt;
        if (hdr->flags & ISCSI_FLAG_CMD_READ) {
                spin_lock_bh(&conn->sess->ttt_lock);
                cmd->targ_xfer_tag = conn->sess->targ_xfer_tag++;
                if (cmd->targ_xfer_tag == 0xFFFFFFFF)
                        cmd->targ_xfer_tag = conn->sess->targ_xfer_tag++;
                spin_unlock_bh(&conn->sess->ttt_lock);
        } else if (hdr->flags & ISCSI_FLAG_CMD_WRITE)
                cmd->targ_xfer_tag = 0xFFFFFFFF;
        cmd->cmd_sn             = be32_to_cpu(hdr->cmdsn);
        cmd->exp_stat_sn        = be32_to_cpu(hdr->exp_statsn);
        cmd->first_burst_len    = payload_length;

        if (cmd->data_direction == DMA_FROM_DEVICE) {
                struct iscsi_datain_req *dr;

                dr = iscsit_allocate_datain_req();
                if (!dr)
                        return iscsit_add_reject_from_cmd(
                                        ISCSI_REASON_BOOKMARK_NO_RESOURCES,
                                        1, 1, buf, cmd);

                iscsit_attach_datain_req(cmd, dr);
        }

        /*
         * Initialize struct se_cmd descriptor from target_core_mod infrastructure
         */
        transport_init_se_cmd(&cmd->se_cmd, &lio_target_fabric_configfs->tf_ops,
                        conn->sess->se_sess, be32_to_cpu(hdr->data_length),
                        cmd->data_direction, sam_task_attr,
                        cmd->sense_buffer + 2);

        pr_debug("Got SCSI Command, ITT: 0x%08x, CmdSN: 0x%08x,"
                " ExpXferLen: %u, Length: %u, CID: %hu\n", hdr->itt,
                hdr->cmdsn, hdr->data_length, payload_length, conn->cid);

        /*
         * The CDB is going to an se_device_t.
         */
        ret = transport_lookup_cmd_lun(&cmd->se_cmd,
                                       scsilun_to_int(&hdr->lun));
        if (ret < 0) {
                if (cmd->se_cmd.scsi_sense_reason == TCM_NON_EXISTENT_LUN) {
                        pr_debug("Responding to non-acl'ed,"
                                " non-existent or non-exported iSCSI LUN:"
                                " 0x%016Lx\n", get_unaligned_le64(&hdr->lun));
                }
                send_check_condition = 1;
                goto attach_cmd;
        }

        transport_ret = target_setup_cmd_from_cdb(&cmd->se_cmd, hdr->cdb);
        if (transport_ret == -ENOMEM) {
                return iscsit_add_reject_from_cmd(
                                ISCSI_REASON_BOOKMARK_NO_RESOURCES,
                                1, 1, buf, cmd);
        } else if (transport_ret < 0) {
                /*
                 * Unsupported SAM Opcode.  CHECK_CONDITION will be sent
                 * in iscsit_execute_cmd() during the CmdSN OOO Execution
                 * Mechinism.
                 */
                send_check_condition = 1;
        } else {
                if (iscsit_build_pdu_and_seq_lists(cmd, payload_length) < 0)
                        return iscsit_add_reject_from_cmd(
                                ISCSI_REASON_BOOKMARK_NO_RESOURCES,
                                1, 1, buf, cmd);
        }

attach_cmd:
        spin_lock_bh(&conn->cmd_lock);
        list_add_tail(&cmd->i_conn_node, &conn->conn_cmd_list);
        spin_unlock_bh(&conn->cmd_lock);
        /*
         * Check if we need to delay processing because of ALUA
         * Active/NonOptimized primary access state..
         */

        core_alua_check_nonop_delay(&cmd->se_cmd);

        ret = iscsit_allocate_iovecs(cmd);
        if (ret < 0)
                return iscsit_add_reject_from_cmd(
                                ISCSI_REASON_BOOKMARK_NO_RESOURCES,
                                1, 0, buf, cmd);
        /*
         * Check the CmdSN against ExpCmdSN/MaxCmdSN here if
         * the Immediate Bit is not set, and no Immediate
         * Data is attached.
         *
         * A PDU/CmdSN carrying Immediate Data can only
         * be processed after the DataCRC has passed.
         * If the DataCRC fails, the CmdSN MUST NOT
         * be acknowledged. (See below)
         */
        if (!cmd->immediate_data) {
                cmdsn_ret = iscsit_sequence_cmd(conn, cmd, hdr->cmdsn);
                if (cmdsn_ret == CMDSN_LOWER_THAN_EXP)
                        return 0;
                else if (cmdsn_ret == CMDSN_ERROR_CANNOT_RECOVER)
                        return iscsit_add_reject_from_cmd(
                                ISCSI_REASON_PROTOCOL_ERROR,
                                1, 0, buf, cmd);
        }

        iscsit_ack_from_expstatsn(conn, be32_to_cpu(hdr->exp_statsn));

        /*
         * If no Immediate Data is attached, it's OK to return now.
         */
        if (!cmd->immediate_data) {
                if (send_check_condition)
                        return 0;

                if (cmd->unsolicited_data) {
                        iscsit_set_dataout_sequence_values(cmd);

                        spin_lock_bh(&cmd->dataout_timeout_lock);
                        iscsit_start_dataout_timer(cmd, cmd->conn);
                        spin_unlock_bh(&cmd->dataout_timeout_lock);
                }

                return 0;
        }

        /*
         * Early CHECK_CONDITIONs never make it to the transport processing
         * thread.  They are processed in CmdSN order by
         * iscsit_check_received_cmdsn() below.
         */
        if (send_check_condition) {
                immed_ret = IMMEDIATE_DATA_NORMAL_OPERATION;
                dump_immediate_data = 1;
                goto after_immediate_data;
        }
        /*
         * Call directly into transport_generic_new_cmd() to perform
         * the backend memory allocation.
         */
        ret = transport_generic_new_cmd(&cmd->se_cmd);
        if (ret < 0) {
                immed_ret = IMMEDIATE_DATA_NORMAL_OPERATION;
                dump_immediate_data = 1;
                goto after_immediate_data;
        }

        immed_ret = iscsit_handle_immediate_data(cmd, buf, payload_length);
after_immediate_data:
        if (immed_ret == IMMEDIATE_DATA_NORMAL_OPERATION) {
                /*
                 * A PDU/CmdSN carrying Immediate Data passed
                 * DataCRC, check against ExpCmdSN/MaxCmdSN if
                 * Immediate Bit is not set.
                 */
                cmdsn_ret = iscsit_sequence_cmd(conn, cmd, hdr->cmdsn);
                /*
                 * Special case for Unsupported SAM WRITE Opcodes
                 * and ImmediateData=Yes.
                 */
                if (dump_immediate_data) {
                        if (iscsit_dump_data_payload(conn, payload_length, 1) < 0)
                                return -1;
                } else if (cmd->unsolicited_data) {
                        iscsit_set_dataout_sequence_values(cmd);

                        spin_lock_bh(&cmd->dataout_timeout_lock);
                        iscsit_start_dataout_timer(cmd, cmd->conn);
                        spin_unlock_bh(&cmd->dataout_timeout_lock);
                }

                if (cmdsn_ret == CMDSN_ERROR_CANNOT_RECOVER)
                        return iscsit_add_reject_from_cmd(
                                ISCSI_REASON_PROTOCOL_ERROR,
                                1, 0, buf, cmd);

        } else if (immed_ret == IMMEDIATE_DATA_ERL1_CRC_FAILURE) {
                /*
                 * Immediate Data failed DataCRC and ERL>=1,
                 * silently drop this PDU and let the initiator
                 * plug the CmdSN gap.
                 *
                 * FIXME: Send Unsolicited NOPIN with reserved
                 * TTT here to help the initiator figure out
                 * the missing CmdSN, although they should be
                 * intelligent enough to determine the missing
                 * CmdSN and issue a retry to plug the sequence.
                 */
                cmd->i_state = ISTATE_REMOVE;
                iscsit_add_cmd_to_immediate_queue(cmd, conn, cmd->i_state);
        } else /* immed_ret == IMMEDIATE_DATA_CANNOT_RECOVER */
                return -1;

        return 0;
}

static u32 iscsit_do_crypto_hash_sg(
        struct hash_desc *hash,
        struct iscsi_cmd *cmd,
        u32 data_offset,
        u32 data_length,
        u32 padding,
        u8 *pad_bytes)
{
        u32 data_crc;
        u32 i;
        struct scatterlist *sg;
        unsigned int page_off;

        crypto_hash_init(hash);

        sg = cmd->first_data_sg;
        page_off = cmd->first_data_sg_off;

        i = 0;
        while (data_length) {
                u32 cur_len = min_t(u32, data_length, (sg[i].length - page_off));

                crypto_hash_update(hash, &sg[i], cur_len);

                data_length -= cur_len;
                page_off = 0;
                i++;
        }

        if (padding) {
                struct scatterlist pad_sg;

                sg_init_one(&pad_sg, pad_bytes, padding);
                crypto_hash_update(hash, &pad_sg, padding);
        }
        crypto_hash_final(hash, (u8 *) &data_crc);

        return data_crc;
}

static void iscsit_do_crypto_hash_buf(
        struct hash_desc *hash,
        unsigned char *buf,
        u32 payload_length,
        u32 padding,
        u8 *pad_bytes,
        u8 *data_crc)
{
        struct scatterlist sg;

        crypto_hash_init(hash);

        sg_init_one(&sg, buf, payload_length);
        crypto_hash_update(hash, &sg, payload_length);

        if (padding) {
                sg_init_one(&sg, pad_bytes, padding);
                crypto_hash_update(hash, &sg, padding);
        }
        crypto_hash_final(hash, data_crc);
}

static int iscsit_handle_data_out(struct iscsi_conn *conn, unsigned char *buf)
{
        int iov_ret, ooo_cmdsn = 0, ret;
        u8 data_crc_failed = 0;
        u32 checksum, iov_count = 0, padding = 0, rx_got = 0;
        u32 rx_size = 0, payload_length;
        struct iscsi_cmd *cmd = NULL;
        struct se_cmd *se_cmd;
        struct iscsi_data *hdr;
        struct kvec *iov;
        unsigned long flags;

        hdr                     = (struct iscsi_data *) buf;
        payload_length          = ntoh24(hdr->dlength);

        if (!payload_length) {
                pr_err("DataOUT payload is ZERO, protocol error.\n");
                return iscsit_add_reject(ISCSI_REASON_PROTOCOL_ERROR, 1,
                                        buf, conn);
        }

        /* iSCSI write */
        spin_lock_bh(&conn->sess->session_stats_lock);
        conn->sess->rx_data_octets += payload_length;
        if (conn->sess->se_sess->se_node_acl) {
                spin_lock(&conn->sess->se_sess->se_node_acl->stats_lock);
                conn->sess->se_sess->se_node_acl->write_bytes += payload_length;
                spin_unlock(&conn->sess->se_sess->se_node_acl->stats_lock);
        }
        spin_unlock_bh(&conn->sess->session_stats_lock);

        if (payload_length > conn->conn_ops->MaxXmitDataSegmentLength) {
                pr_err("DataSegmentLength: %u is greater than"
                        " MaxXmitDataSegmentLength: %u\n", payload_length,
                        conn->conn_ops->MaxXmitDataSegmentLength);
                return iscsit_add_reject(ISCSI_REASON_PROTOCOL_ERROR, 1,
                                        buf, conn);
        }

        cmd = iscsit_find_cmd_from_itt_or_dump(conn, hdr->itt,
                        payload_length);
        if (!cmd)
                return 0;

        pr_debug("Got DataOut ITT: 0x%08x, TTT: 0x%08x,"
                " DataSN: 0x%08x, Offset: %u, Length: %u, CID: %hu\n",
                hdr->itt, hdr->ttt, hdr->datasn, hdr->offset,
                payload_length, conn->cid);

        if (cmd->cmd_flags & ICF_GOT_LAST_DATAOUT) {
                pr_err("Command ITT: 0x%08x received DataOUT after"
                        " last DataOUT received, dumping payload\n",
                        cmd->init_task_tag);
                return iscsit_dump_data_payload(conn, payload_length, 1);
        }

        if (cmd->data_direction != DMA_TO_DEVICE) {
                pr_err("Command ITT: 0x%08x received DataOUT for a"
                        " NON-WRITE command.\n", cmd->init_task_tag);
                return iscsit_add_reject_from_cmd(ISCSI_REASON_PROTOCOL_ERROR,
                                1, 0, buf, cmd);
        }
        se_cmd = &cmd->se_cmd;
        iscsit_mod_dataout_timer(cmd);

        if ((be32_to_cpu(hdr->offset) + payload_length) > cmd->se_cmd.data_length) {
                pr_err("DataOut Offset: %u, Length %u greater than"
                        " iSCSI Command EDTL %u, protocol error.\n",
                        hdr->offset, payload_length, cmd->se_cmd.data_length);
                return iscsit_add_reject_from_cmd(ISCSI_REASON_BOOKMARK_INVALID,
                                1, 0, buf, cmd);
        }

        if (cmd->unsolicited_data) {
                int dump_unsolicited_data = 0;

                if (conn->sess->sess_ops->InitialR2T) {
                        pr_err("Received unexpected unsolicited data"
                                " while InitialR2T=Yes, protocol error.\n");
                        transport_send_check_condition_and_sense(&cmd->se_cmd,
                                        TCM_UNEXPECTED_UNSOLICITED_DATA, 0);
                        return -1;
                }
                /*
                 * Special case for dealing with Unsolicited DataOUT
                 * and Unsupported SAM WRITE Opcodes and SE resource allocation
                 * failures;
                 */

                /* Something's amiss if we're not in WRITE_PENDING state... */
                spin_lock_irqsave(&se_cmd->t_state_lock, flags);
                WARN_ON(se_cmd->t_state != TRANSPORT_WRITE_PENDING);
                spin_unlock_irqrestore(&se_cmd->t_state_lock, flags);

                spin_lock_irqsave(&se_cmd->t_state_lock, flags);
                if (!(se_cmd->se_cmd_flags & SCF_SUPPORTED_SAM_OPCODE) ||
                     (se_cmd->se_cmd_flags & SCF_SCSI_CDB_EXCEPTION))
                        dump_unsolicited_data = 1;
                spin_unlock_irqrestore(&se_cmd->t_state_lock, flags);

                if (dump_unsolicited_data) {
                        /*
                         * Check if a delayed TASK_ABORTED status needs to
                         * be sent now if the ISCSI_FLAG_CMD_FINAL has been
                         * received with the unsolicitied data out.
                         */
                        if (hdr->flags & ISCSI_FLAG_CMD_FINAL)
                                iscsit_stop_dataout_timer(cmd);

                        transport_check_aborted_status(se_cmd,
                                        (hdr->flags & ISCSI_FLAG_CMD_FINAL));
                        return iscsit_dump_data_payload(conn, payload_length, 1);
                }
        } else {
                /*
                 * For the normal solicited data path:
                 *
                 * Check for a delayed TASK_ABORTED status and dump any
                 * incoming data out payload if one exists.  Also, when the
                 * ISCSI_FLAG_CMD_FINAL is set to denote the end of the current
                 * data out sequence, we decrement outstanding_r2ts.  Once
                 * outstanding_r2ts reaches zero, go ahead and send the delayed
                 * TASK_ABORTED status.
                 */
                if (se_cmd->transport_state & CMD_T_ABORTED) {
                        if (hdr->flags & ISCSI_FLAG_CMD_FINAL)
                                if (--cmd->outstanding_r2ts < 1) {
                                        iscsit_stop_dataout_timer(cmd);
                                        transport_check_aborted_status(
                                                        se_cmd, 1);
                                }

                        return iscsit_dump_data_payload(conn, payload_length, 1);
                }
        }
        /*
         * Preform DataSN, DataSequenceInOrder, DataPDUInOrder, and
         * within-command recovery checks before receiving the payload.
         */
        ret = iscsit_check_pre_dataout(cmd, buf);
        if (ret == DATAOUT_WITHIN_COMMAND_RECOVERY)
                return 0;
        else if (ret == DATAOUT_CANNOT_RECOVER)
                return -1;

        rx_size += payload_length;
        iov = &cmd->iov_data[0];

        iov_ret = iscsit_map_iovec(cmd, iov, be32_to_cpu(hdr->offset),
                                   payload_length);
        if (iov_ret < 0)
                return -1;

        iov_count += iov_ret;

        padding = ((-payload_length) & 3);
        if (padding != 0) {
                iov[iov_count].iov_base = cmd->pad_bytes;
                iov[iov_count++].iov_len = padding;
                rx_size += padding;
                pr_debug("Receiving %u padding bytes.\n", padding);
        }

        if (conn->conn_ops->DataDigest) {
                iov[iov_count].iov_base = &checksum;
                iov[iov_count++].iov_len = ISCSI_CRC_LEN;
                rx_size += ISCSI_CRC_LEN;
        }

        rx_got = rx_data(conn, &cmd->iov_data[0], iov_count, rx_size);

        iscsit_unmap_iovec(cmd);

        if (rx_got != rx_size)
                return -1;

        if (conn->conn_ops->DataDigest) {
                u32 data_crc;

                data_crc = iscsit_do_crypto_hash_sg(&conn->conn_rx_hash, cmd,
                                                    be32_to_cpu(hdr->offset),
                                                    payload_length, padding,
                                                    cmd->pad_bytes);

                if (checksum != data_crc) {
                        pr_err("ITT: 0x%08x, Offset: %u, Length: %u,"
                                " DataSN: 0x%08x, CRC32C DataDigest 0x%08x"
                                " does not match computed 0x%08x\n",
                                hdr->itt, hdr->offset, payload_length,
                                hdr->datasn, checksum, data_crc);
                        data_crc_failed = 1;
                } else {
                        pr_debug("Got CRC32C DataDigest 0x%08x for"
                                " %u bytes of Data Out\n", checksum,
                                payload_length);
                }
        }
        /*
         * Increment post receive data and CRC values or perform
         * within-command recovery.
         */
        ret = iscsit_check_post_dataout(cmd, buf, data_crc_failed);
        if ((ret == DATAOUT_NORMAL) || (ret == DATAOUT_WITHIN_COMMAND_RECOVERY))
                return 0;
        else if (ret == DATAOUT_SEND_R2T) {
                iscsit_set_dataout_sequence_values(cmd);
                iscsit_build_r2ts_for_cmd(cmd, conn, false);
        } else if (ret == DATAOUT_SEND_TO_TRANSPORT) {
                /*
                 * Handle extra special case for out of order
                 * Unsolicited Data Out.
                 */
                spin_lock_bh(&cmd->istate_lock);
                ooo_cmdsn = (cmd->cmd_flags & ICF_OOO_CMDSN);
                cmd->cmd_flags |= ICF_GOT_LAST_DATAOUT;
                cmd->i_state = ISTATE_RECEIVED_LAST_DATAOUT;
                spin_unlock_bh(&cmd->istate_lock);

                iscsit_stop_dataout_timer(cmd);
                if (ooo_cmdsn)
                        return 0;
                target_execute_cmd(&cmd->se_cmd);
                return 0;
        } else /* DATAOUT_CANNOT_RECOVER */
                return -1;

        return 0;
}

static int iscsit_handle_nop_out(
        struct iscsi_conn *conn,
        unsigned char *buf)
{
        unsigned char *ping_data = NULL;
        int cmdsn_ret, niov = 0, ret = 0, rx_got, rx_size;
        u32 checksum, data_crc, padding = 0, payload_length;
        struct iscsi_cmd *cmd = NULL;
        struct kvec *iov = NULL;
        struct iscsi_nopout *hdr;

        hdr                     = (struct iscsi_nopout *) buf;
        payload_length          = ntoh24(hdr->dlength);

        if (hdr->itt == RESERVED_ITT && !(hdr->opcode & ISCSI_OP_IMMEDIATE)) {
                pr_err("NOPOUT ITT is reserved, but Immediate Bit is"
                        " not set, protocol error.\n");
                return iscsit_add_reject(ISCSI_REASON_PROTOCOL_ERROR, 1,
                                        buf, conn);
        }

        if (payload_length > conn->conn_ops->MaxXmitDataSegmentLength) {
                pr_err("NOPOUT Ping Data DataSegmentLength: %u is"
                        " greater than MaxXmitDataSegmentLength: %u, protocol"
                        " error.\n", payload_length,
                        conn->conn_ops->MaxXmitDataSegmentLength);
                return iscsit_add_reject(ISCSI_REASON_PROTOCOL_ERROR, 1,
                                        buf, conn);
        }

        pr_debug("Got NOPOUT Ping %s ITT: 0x%08x, TTT: 0x%09x,"
                " CmdSN: 0x%08x, ExpStatSN: 0x%08x, Length: %u\n",
                hdr->itt == RESERVED_ITT ? "Response" : "Request",
                hdr->itt, hdr->ttt, hdr->cmdsn, hdr->exp_statsn,
                payload_length);
        /*
         * This is not a response to a Unsolicited NopIN, which means
         * it can either be a NOPOUT ping request (with a valid ITT),
         * or a NOPOUT not requesting a NOPIN (with a reserved ITT).
         * Either way, make sure we allocate an struct iscsi_cmd, as both
         * can contain ping data.
         */
        if (hdr->ttt == cpu_to_be32(0xFFFFFFFF)) {
                cmd = iscsit_allocate_cmd(conn, GFP_KERNEL);
                if (!cmd)
                        return iscsit_add_reject(
                                        ISCSI_REASON_BOOKMARK_NO_RESOURCES,
                                        1, buf, conn);

                cmd->iscsi_opcode       = ISCSI_OP_NOOP_OUT;
                cmd->i_state            = ISTATE_SEND_NOPIN;
                cmd->immediate_cmd      = ((hdr->opcode & ISCSI_OP_IMMEDIATE) ?
                                                1 : 0);
                conn->sess->init_task_tag = cmd->init_task_tag = hdr->itt;
                cmd->targ_xfer_tag      = 0xFFFFFFFF;
                cmd->cmd_sn             = be32_to_cpu(hdr->cmdsn);
                cmd->exp_stat_sn        = be32_to_cpu(hdr->exp_statsn);
                cmd->data_direction     = DMA_NONE;
        }

        if (payload_length && hdr->ttt == cpu_to_be32(0xFFFFFFFF)) {
                rx_size = payload_length;
                ping_data = kzalloc(payload_length + 1, GFP_KERNEL);
                if (!ping_data) {
                        pr_err("Unable to allocate memory for"
                                " NOPOUT ping data.\n");
                        ret = -1;
                        goto out;
                }

                iov = &cmd->iov_misc[0];
                iov[niov].iov_base      = ping_data;
                iov[niov++].iov_len     = payload_length;

                padding = ((-payload_length) & 3);
                if (padding != 0) {
                        pr_debug("Receiving %u additional bytes"
                                " for padding.\n", padding);
                        iov[niov].iov_base      = &cmd->pad_bytes;
                        iov[niov++].iov_len     = padding;
                        rx_size += padding;
                }
                if (conn->conn_ops->DataDigest) {
                        iov[niov].iov_base      = &checksum;
                        iov[niov++].iov_len     = ISCSI_CRC_LEN;
                        rx_size += ISCSI_CRC_LEN;
                }

                rx_got = rx_data(conn, &cmd->iov_misc[0], niov, rx_size);
                if (rx_got != rx_size) {
                        ret = -1;
                        goto out;
                }

                if (conn->conn_ops->DataDigest) {
                        iscsit_do_crypto_hash_buf(&conn->conn_rx_hash,
                                        ping_data, payload_length,
                                        padding, cmd->pad_bytes,
                                        (u8 *)&data_crc);

                        if (checksum != data_crc) {
                                pr_err("Ping data CRC32C DataDigest"
                                " 0x%08x does not match computed 0x%08x\n",
                                        checksum, data_crc);
                                if (!conn->sess->sess_ops->ErrorRecoveryLevel) {
                                        pr_err("Unable to recover from"
                                        " NOPOUT Ping DataCRC failure while in"
                                                " ERL=0.\n");
                                        ret = -1;
                                        goto out;
                                } else {
                                        /*
                                         * Silently drop this PDU and let the
                                         * initiator plug the CmdSN gap.
                                         */
                                        pr_debug("Dropping NOPOUT"
                                        " Command CmdSN: 0x%08x due to"
                                        " DataCRC error.\n", hdr->cmdsn);
                                        ret = 0;
                                        goto out;
                                }
                        } else {
                                pr_debug("Got CRC32C DataDigest"
                                " 0x%08x for %u bytes of ping data.\n",
                                        checksum, payload_length);
                        }
                }

                ping_data[payload_length] = '\0';
                /*
                 * Attach ping data to struct iscsi_cmd->buf_ptr.
                 */
                cmd->buf_ptr = ping_data;
                cmd->buf_ptr_size = payload_length;

                pr_debug("Got %u bytes of NOPOUT ping"
                        " data.\n", payload_length);
                pr_debug("Ping Data: \"%s\"\n", ping_data);
        }

        if (hdr->itt != RESERVED_ITT) {
                if (!cmd) {
                        pr_err("Checking CmdSN for NOPOUT,"
                                " but cmd is NULL!\n");
                        return -1;
                }
                /*
                 * Initiator is expecting a NopIN ping reply,
                 */
                spin_lock_bh(&conn->cmd_lock);
                list_add_tail(&cmd->i_conn_node, &conn->conn_cmd_list);
                spin_unlock_bh(&conn->cmd_lock);

                iscsit_ack_from_expstatsn(conn, be32_to_cpu(hdr->exp_statsn));

                if (hdr->opcode & ISCSI_OP_IMMEDIATE) {
                        iscsit_add_cmd_to_response_queue(cmd, conn,
                                        cmd->i_state);
                        return 0;
                }

                cmdsn_ret = iscsit_sequence_cmd(conn, cmd, hdr->cmdsn);
                if (cmdsn_ret == CMDSN_LOWER_THAN_EXP) {
                        ret = 0;
                        goto ping_out;
                }
                if (cmdsn_ret == CMDSN_ERROR_CANNOT_RECOVER)
                        return iscsit_add_reject_from_cmd(
                                        ISCSI_REASON_PROTOCOL_ERROR,
                                        1, 0, buf, cmd);

                return 0;
        }

        if (hdr->ttt != cpu_to_be32(0xFFFFFFFF)) {
                /*
                 * This was a response to a unsolicited NOPIN ping.
                 */
                cmd = iscsit_find_cmd_from_ttt(conn, be32_to_cpu(hdr->ttt));
                if (!cmd)
                        return -1;

                iscsit_stop_nopin_response_timer(conn);

                cmd->i_state = ISTATE_REMOVE;
                iscsit_add_cmd_to_immediate_queue(cmd, conn, cmd->i_state);
                iscsit_start_nopin_timer(conn);
        } else {
                /*
                 * Initiator is not expecting a NOPIN is response.
                 * Just ignore for now.
                 *
                 * iSCSI v19-91 10.18
                 * "A NOP-OUT may also be used to confirm a changed
                 *  ExpStatSN if another PDU will not be available
                 *  for a long time."
                 */
                ret = 0;
                goto out;
        }

        return 0;
out:
        if (cmd)
                iscsit_release_cmd(cmd);
ping_out:
        kfree(ping_data);
        return ret;
}

static int iscsit_handle_task_mgt_cmd(
        struct iscsi_conn *conn,
        unsigned char *buf)
{
        struct iscsi_cmd *cmd;
        struct se_tmr_req *se_tmr;
        struct iscsi_tmr_req *tmr_req;
        struct iscsi_tm *hdr;
        int out_of_order_cmdsn = 0;
        int ret;
        u8 function;

        hdr                     = (struct iscsi_tm *) buf;
        hdr->flags &= ~ISCSI_FLAG_CMD_FINAL;
        function = hdr->flags;

        pr_debug("Got Task Management Request ITT: 0x%08x, CmdSN:"
                " 0x%08x, Function: 0x%02x, RefTaskTag: 0x%08x, RefCmdSN:"
                " 0x%08x, CID: %hu\n", hdr->itt, hdr->cmdsn, function,
                hdr->rtt, hdr->refcmdsn, conn->cid);

        if ((function != ISCSI_TM_FUNC_ABORT_TASK) &&
            ((function != ISCSI_TM_FUNC_TASK_REASSIGN) &&
             hdr->rtt != RESERVED_ITT)) {
                pr_err("RefTaskTag should be set to 0xFFFFFFFF.\n");
                hdr->rtt = RESERVED_ITT;
        }

        if ((function == ISCSI_TM_FUNC_TASK_REASSIGN) &&
                        !(hdr->opcode & ISCSI_OP_IMMEDIATE)) {
                pr_err("Task Management Request TASK_REASSIGN not"
                        " issued as immediate command, bad iSCSI Initiator"
                                "implementation\n");
                return iscsit_add_reject(ISCSI_REASON_PROTOCOL_ERROR, 1,
                                        buf, conn);
        }
        if ((function != ISCSI_TM_FUNC_ABORT_TASK) &&
            be32_to_cpu(hdr->refcmdsn) != ISCSI_RESERVED_TAG)
                hdr->refcmdsn = cpu_to_be32(ISCSI_RESERVED_TAG);

        cmd = iscsit_allocate_cmd(conn, GFP_KERNEL);
        if (!cmd)
                return iscsit_add_reject(ISCSI_REASON_BOOKMARK_NO_RESOURCES,
                                         1, buf, conn);

        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");
                return iscsit_add_reject_from_cmd(
                        ISCSI_REASON_BOOKMARK_NO_RESOURCES,
                        1, 1, buf, cmd);
        }

        /*
         * TASK_REASSIGN for ERL=2 / connection stays inside of
         * LIO-Target $FABRIC_MOD
         */
        if (function != ISCSI_TM_FUNC_TASK_REASSIGN) {

                u8 tcm_function;
                int ret;

                transport_init_se_cmd(&cmd->se_cmd,
                                      &lio_target_fabric_configfs->tf_ops,
                                      conn->sess->se_sess, 0, DMA_NONE,
                                      MSG_SIMPLE_TAG, cmd->sense_buffer + 2);

                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);
                        return iscsit_add_reject_from_cmd(
                                ISCSI_REASON_BOOKMARK_NO_RESOURCES,
                                1, 1, buf, cmd);
                }

                ret = core_tmr_alloc_req(&cmd->se_cmd, cmd->tmr_req,
                                         tcm_function, GFP_KERNEL);
                if (ret < 0)
                        return iscsit_add_reject_from_cmd(
                                ISCSI_REASON_BOOKMARK_NO_RESOURCES,
                                1, 1, buf, cmd);

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

        cmd->iscsi_opcode       = ISCSI_OP_SCSI_TMFUNC;
        cmd->i_state            = ISTATE_SEND_TASKMGTRSP;
        cmd->immediate_cmd      = ((hdr->opcode & ISCSI_OP_IMMEDIATE) ? 1 : 0);
        cmd->init_task_tag      = hdr->itt;
        cmd->targ_xfer_tag      = 0xFFFFFFFF;
        cmd->cmd_sn             = be32_to_cpu(hdr->cmdsn);
        cmd->exp_stat_sn        = be32_to_cpu(hdr->exp_statsn);
        se_tmr                  = cmd->se_cmd.se_tmr_req;
        tmr_req                 = cmd->tmr_req;
        /*
         * Locate the struct se_lun for all TMRs not related to ERL=2 TASK_REASSIGN
         */
        if (function != ISCSI_TM_FUNC_TASK_REASSIGN) {
                ret = transport_lookup_tmr_lun(&cmd->se_cmd,
                                               scsilun_to_int(&hdr->lun));
                if (ret < 0) {
                        cmd->se_cmd.se_cmd_flags |= SCF_SCSI_CDB_EXCEPTION;
                        se_tmr->response = ISCSI_TMF_RSP_NO_LUN;
                        goto attach;
                }
        }

        switch (function) {
        case ISCSI_TM_FUNC_ABORT_TASK:
                se_tmr->response = iscsit_tmr_abort_task(cmd, buf);
                if (se_tmr->response != ISCSI_TMF_RSP_COMPLETE) {
                        cmd->se_cmd.se_cmd_flags |= SCF_SCSI_CDB_EXCEPTION;
                        goto attach;
                }
                break;
        case ISCSI_TM_FUNC_ABORT_TASK_SET:
        case ISCSI_TM_FUNC_CLEAR_ACA:
        case ISCSI_TM_FUNC_CLEAR_TASK_SET:
        case ISCSI_TM_FUNC_LOGICAL_UNIT_RESET:
                break;
        case ISCSI_TM_FUNC_TARGET_WARM_RESET:
                if (iscsit_tmr_task_warm_reset(conn, tmr_req, buf) < 0) {
                        cmd->se_cmd.se_cmd_flags |= SCF_SCSI_CDB_EXCEPTION;
                        se_tmr->response = ISCSI_TMF_RSP_AUTH_FAILED;
                        goto attach;
                }
                break;
        case ISCSI_TM_FUNC_TARGET_COLD_RESET:
                if (iscsit_tmr_task_cold_reset(conn, tmr_req, buf) < 0) {
                        cmd->se_cmd.se_cmd_flags |= SCF_SCSI_CDB_EXCEPTION;
                        se_tmr->response = ISCSI_TMF_RSP_AUTH_FAILED;
                        goto attach;
                }
                break;
        case ISCSI_TM_FUNC_TASK_REASSIGN:
                se_tmr->response = iscsit_tmr_task_reassign(cmd, buf);
                /*
                 * Perform sanity checks on the ExpDataSN only if the
                 * TASK_REASSIGN was successful.
                 */
                if (se_tmr->response != ISCSI_TMF_RSP_COMPLETE)
                        break;

                if (iscsit_check_task_reassign_expdatasn(tmr_req, conn) < 0)
                        return iscsit_add_reject_from_cmd(
                                        ISCSI_REASON_BOOKMARK_INVALID, 1, 1,
                                        buf, cmd);
                break;
        default:
                pr_err("Unknown TMR function: 0x%02x, protocol"
                        " error.\n", function);
                cmd->se_cmd.se_cmd_flags |= SCF_SCSI_CDB_EXCEPTION;
                se_tmr->response = ISCSI_TMF_RSP_NOT_SUPPORTED;
                goto attach;
        }

        if ((function != ISCSI_TM_FUNC_TASK_REASSIGN) &&
            (se_tmr->response == ISCSI_TMF_RSP_COMPLETE))
                se_tmr->call_transport = 1;
attach:
        spin_lock_bh(&conn->cmd_lock);
        list_add_tail(&cmd->i_conn_node, &conn->conn_cmd_list);
        spin_unlock_bh(&conn->cmd_lock);

        if (!(hdr->opcode & ISCSI_OP_IMMEDIATE)) {
                int cmdsn_ret = iscsit_sequence_cmd(conn, cmd, hdr->cmdsn);
                if (cmdsn_ret == CMDSN_HIGHER_THAN_EXP)
                        out_of_order_cmdsn = 1;
                else if (cmdsn_ret == CMDSN_LOWER_THAN_EXP)
                        return 0;
                else if (cmdsn_ret == CMDSN_ERROR_CANNOT_RECOVER)
                        return iscsit_add_reject_from_cmd(
                                        ISCSI_REASON_PROTOCOL_ERROR,
                                        1, 0, buf, cmd);
        }
        iscsit_ack_from_expstatsn(conn, be32_to_cpu(hdr->exp_statsn));

        if (out_of_order_cmdsn || !(hdr->opcode & ISCSI_OP_IMMEDIATE))
                return 0;
        /*
         * Found the referenced task, send to transport for processing.
         */
        if (se_tmr->call_transport)
                return transport_generic_handle_tmr(&cmd->se_cmd);

        /*
         * Could not find the referenced LUN, task, or Task Management
         * command not authorized or supported.  Change state and
         * let the tx_thread send the response.
         *
         * For connection recovery, this is also the default action for
         * TMR TASK_REASSIGN.
         */
        iscsit_add_cmd_to_response_queue(cmd, conn, cmd->i_state);
        return 0;
}

/* #warning FIXME: Support Text Command parameters besides SendTargets */
static int iscsit_handle_text_cmd(
        struct iscsi_conn *conn,
        unsigned char *buf)
{
        char *text_ptr, *text_in;
        int cmdsn_ret, niov = 0, rx_got, rx_size;
        u32 checksum = 0, data_crc = 0, payload_length;
        u32 padding = 0, pad_bytes = 0, text_length = 0;
        struct iscsi_cmd *cmd;
        struct kvec iov[3];
        struct iscsi_text *hdr;

        hdr                     = (struct iscsi_text *) buf;
        payload_length          = ntoh24(hdr->dlength);

        if (payload_length > conn->conn_ops->MaxXmitDataSegmentLength) {
                pr_err("Unable to accept text parameter length: %u"
                        "greater than MaxXmitDataSegmentLength %u.\n",
                       payload_length, conn->conn_ops->MaxXmitDataSegmentLength);
                return iscsit_add_reject(ISCSI_REASON_PROTOCOL_ERROR, 1,
                                        buf, conn);
        }

        pr_debug("Got Text Request: ITT: 0x%08x, CmdSN: 0x%08x,"
                " ExpStatSN: 0x%08x, Length: %u\n", hdr->itt, hdr->cmdsn,
                hdr->exp_statsn, payload_length);

        rx_size = text_length = payload_length;
        if (text_length) {
                text_in = kzalloc(text_length, GFP_KERNEL);
                if (!text_in) {
                        pr_err("Unable to allocate memory for"
                                " incoming text parameters\n");
                        return -1;
                }

                memset(iov, 0, 3 * sizeof(struct kvec));
                iov[niov].iov_base      = text_in;
                iov[niov++].iov_len     = text_length;

                padding = ((-payload_length) & 3);
                if (padding != 0) {
                        iov[niov].iov_base = &pad_bytes;
                        iov[niov++].iov_len  = padding;
                        rx_size += padding;
                        pr_debug("Receiving %u additional bytes"
                                        " for padding.\n", padding);
                }
                if (conn->conn_ops->DataDigest) {
                        iov[niov].iov_base      = &checksum;
                        iov[niov++].iov_len     = ISCSI_CRC_LEN;
                        rx_size += ISCSI_CRC_LEN;
                }

                rx_got = rx_data(conn, &iov[0], niov, rx_size);
                if (rx_got != rx_size) {
                        kfree(text_in);
                        return -1;
                }

                if (conn->conn_ops->DataDigest) {
                        iscsit_do_crypto_hash_buf(&conn->conn_rx_hash,
                                        text_in, text_length,
                                        padding, (u8 *)&pad_bytes,
                                        (u8 *)&data_crc);

                        if (checksum != data_crc) {
                                pr_err("Text data CRC32C DataDigest"
                                        " 0x%08x does not match computed"
                                        " 0x%08x\n", checksum, data_crc);
                                if (!conn->sess->sess_ops->ErrorRecoveryLevel) {
                                        pr_err("Unable to recover from"
                                        " Text Data digest failure while in"
                                                " ERL=0.\n");
                                        kfree(text_in);
                                        return -1;
                                } else {
                                        /*
                                         * Silently drop this PDU and let the
                                         * initiator plug the CmdSN gap.
                                         */
                                        pr_debug("Dropping Text"
                                        " Command CmdSN: 0x%08x due to"
                                        " DataCRC error.\n", hdr->cmdsn);
                                        kfree(text_in);
                                        return 0;
                                }
                        } else {
                                pr_debug("Got CRC32C DataDigest"
                                        " 0x%08x for %u bytes of text data.\n",
                                                checksum, text_length);
                        }
                }
                text_in[text_length - 1] = '\0';
                pr_debug("Successfully read %d bytes of text"
                                " data.\n", text_length);

                if (strncmp("SendTargets", text_in, 11) != 0) {
                        pr_err("Received Text Data that is not"
                                " SendTargets, cannot continue.\n");
                        kfree(text_in);
                        return -1;
                }
                text_ptr = strchr(text_in, '=');
                if (!text_ptr) {
                        pr_err("No \"=\" separator found in Text Data,"
                                "  cannot continue.\n");
                        kfree(text_in);
                        return -1;
                }
                if (strncmp("=All", text_ptr, 4) != 0) {
                        pr_err("Unable to locate All value for"
                                " SendTargets key,  cannot continue.\n");
                        kfree(text_in);
                        return -1;
                }
/*#warning Support SendTargets=(iSCSI Target Name/Nothing) values. */
                kfree(text_in);
        }

        cmd = iscsit_allocate_cmd(conn, GFP_KERNEL);
        if (!cmd)
                return iscsit_add_reject(ISCSI_REASON_BOOKMARK_NO_RESOURCES,
                                        1, buf, conn);

        cmd->iscsi_opcode       = ISCSI_OP_TEXT;
        cmd->i_state            = ISTATE_SEND_TEXTRSP;
        cmd->immediate_cmd      = ((hdr->opcode & ISCSI_OP_IMMEDIATE) ? 1 : 0);
        conn->sess->init_task_tag = cmd->init_task_tag  = hdr->itt;
        cmd->targ_xfer_tag      = 0xFFFFFFFF;
        cmd->cmd_sn             = be32_to_cpu(hdr->cmdsn);
        cmd->exp_stat_sn        = be32_to_cpu(hdr->exp_statsn);
        cmd->data_direction     = DMA_NONE;

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

        iscsit_ack_from_expstatsn(conn, be32_to_cpu(hdr->exp_statsn));

        if (!(hdr->opcode & ISCSI_OP_IMMEDIATE)) {
                cmdsn_ret = iscsit_sequence_cmd(conn, cmd, hdr->cmdsn);
                if (cmdsn_ret == CMDSN_ERROR_CANNOT_RECOVER)
                        return iscsit_add_reject_from_cmd(
                                        ISCSI_REASON_PROTOCOL_ERROR,
                                        1, 0, buf, cmd);

                return 0;
        }

        return iscsit_execute_cmd(cmd, 0);
}

int iscsit_logout_closesession(struct iscsi_cmd *cmd, struct iscsi_conn *conn)
{
        struct iscsi_conn *conn_p;
        struct iscsi_session *sess = conn->sess;

        pr_debug("Received logout request CLOSESESSION on CID: %hu"

                " for SID: %u.\n", conn->cid, conn->sess->sid);

        atomic_set(&sess->session_logout, 1);
        atomic_set(&conn->conn_logout_remove, 1);
        conn->conn_logout_reason = ISCSI_LOGOUT_REASON_CLOSE_SESSION;

        iscsit_inc_conn_usage_count(conn);
        iscsit_inc_session_usage_count(sess);

        spin_lock_bh(&sess->conn_lock);
        list_for_each_entry(conn_p, &sess->sess_conn_list, conn_list) {
                if (conn_p->conn_state != TARG_CONN_STATE_LOGGED_IN)
                        continue;

                pr_debug("Moving to TARG_CONN_STATE_IN_LOGOUT.\n");
                conn_p->conn_state = TARG_CONN_STATE_IN_LOGOUT;
        }
        spin_unlock_bh(&sess->conn_lock);

        iscsit_add_cmd_to_response_queue(cmd, conn, cmd->i_state);

        return 0;
}

int iscsit_logout_closeconnection(struct iscsi_cmd *cmd, struct iscsi_conn *conn)
{
        struct iscsi_conn *l_conn;
        struct iscsi_session *sess = conn->sess;

        pr_debug("Received logout request CLOSECONNECTION for CID:"
                " %hu on CID: %hu.\n", cmd->logout_cid, conn->cid);

        /*
         * A Logout Request with a CLOSECONNECTION reason code for a CID
         * can arrive on a connection with a differing CID.
         */
        if (conn->cid == cmd->logout_cid) {
                spin_lock_bh(&conn->state_lock);
                pr_debug("Moving to TARG_CONN_STATE_IN_LOGOUT.\n");
                conn->conn_state = TARG_CONN_STATE_IN_LOGOUT;

                atomic_set(&conn->conn_logout_remove, 1);
                conn->conn_logout_reason = ISCSI_LOGOUT_REASON_CLOSE_CONNECTION;
                iscsit_inc_conn_usage_count(conn);

                spin_unlock_bh(&conn->state_lock);
        } else {
                /*
                 * Handle all different cid CLOSECONNECTION requests in
                 * iscsit_logout_post_handler_diffcid() as to give enough
                 * time for any non immediate command's CmdSN to be
                 * acknowledged on the connection in question.
                 *
                 * Here we simply make sure the CID is still around.
                 */
                l_conn = iscsit_get_conn_from_cid(sess,
                                cmd->logout_cid);
                if (!l_conn) {
                        cmd->logout_response = ISCSI_LOGOUT_CID_NOT_FOUND;
                        iscsit_add_cmd_to_response_queue(cmd, conn,
                                        cmd->i_state);
                        return 0;
                }

                iscsit_dec_conn_usage_count(l_conn);
        }

        iscsit_add_cmd_to_response_queue(cmd, conn, cmd->i_state);

        return 0;
}

int iscsit_logout_removeconnforrecovery(struct iscsi_cmd *cmd, struct iscsi_conn *conn)
{
        struct iscsi_session *sess = conn->sess;

        pr_debug("Received explicit REMOVECONNFORRECOVERY logout for"
                " CID: %hu on CID: %hu.\n", cmd->logout_cid, conn->cid);

        if (sess->sess_ops->ErrorRecoveryLevel != 2) {
                pr_err("Received Logout Request REMOVECONNFORRECOVERY"
                        " while ERL!=2.\n");
                cmd->logout_response = ISCSI_LOGOUT_RECOVERY_UNSUPPORTED;
                iscsit_add_cmd_to_response_queue(cmd, conn, cmd->i_state);
                return 0;
        }

        if (conn->cid == cmd->logout_cid) {
                pr_err("Received Logout Request REMOVECONNFORRECOVERY"
                        " with CID: %hu on CID: %hu, implementation error.\n",
                                cmd->logout_cid, conn->cid);
                cmd->logout_response = ISCSI_LOGOUT_CLEANUP_FAILED;
                iscsit_add_cmd_to_response_queue(cmd, conn, cmd->i_state);
                return 0;
        }

        iscsit_add_cmd_to_response_queue(cmd, conn, cmd->i_state);

        return 0;
}

static int iscsit_handle_logout_cmd(
        struct iscsi_conn *conn,
        unsigned char *buf)
{
        int cmdsn_ret, logout_remove = 0;
        u8 reason_code = 0;
        struct iscsi_cmd *cmd;
        struct iscsi_logout *hdr;
        struct iscsi_tiqn *tiqn = iscsit_snmp_get_tiqn(conn);

        hdr                     = (struct iscsi_logout *) buf;
        reason_code             = (hdr->flags & 0x7f);

        if (tiqn) {
                spin_lock(&tiqn->logout_stats.lock);
                if (reason_code == ISCSI_LOGOUT_REASON_CLOSE_SESSION)
                        tiqn->logout_stats.normal_logouts++;
                else
                        tiqn->logout_stats.abnormal_logouts++;
                spin_unlock(&tiqn->logout_stats.lock);
        }

        pr_debug("Got Logout Request ITT: 0x%08x CmdSN: 0x%08x"
                " ExpStatSN: 0x%08x Reason: 0x%02x CID: %hu on CID: %hu\n",
                hdr->itt, hdr->cmdsn, hdr->exp_statsn, reason_code,
                hdr->cid, conn->cid);

        if (conn->conn_state != TARG_CONN_STATE_LOGGED_IN) {
                pr_err("Received logout request on connection that"
                        " is not in logged in state, ignoring request.\n");
                return 0;
        }

        cmd = iscsit_allocate_cmd(conn, GFP_KERNEL);
        if (!cmd)
                return iscsit_add_reject(ISCSI_REASON_BOOKMARK_NO_RESOURCES, 1,
                                        buf, conn);

        cmd->iscsi_opcode       = ISCSI_OP_LOGOUT;
        cmd->i_state            = ISTATE_SEND_LOGOUTRSP;
        cmd->immediate_cmd      = ((hdr->opcode & ISCSI_OP_IMMEDIATE) ? 1 : 0);
        conn->sess->init_task_tag = cmd->init_task_tag  = hdr->itt;
        cmd->targ_xfer_tag      = 0xFFFFFFFF;
        cmd->cmd_sn             = be32_to_cpu(hdr->cmdsn);
        cmd->exp_stat_sn        = be32_to_cpu(hdr->exp_statsn);
        cmd->logout_cid         = be16_to_cpu(hdr->cid);
        cmd->logout_reason      = reason_code;
        cmd->data_direction     = DMA_NONE;

        /*
         * We need to sleep in these cases (by returning 1) until the Logout
         * Response gets sent in the tx thread.
         */
        if ((reason_code == ISCSI_LOGOUT_REASON_CLOSE_SESSION) ||
           ((reason_code == ISCSI_LOGOUT_REASON_CLOSE_CONNECTION) &&
            be16_to_cpu(hdr->cid) == conn->cid))
                logout_remove = 1;

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

        if (reason_code != ISCSI_LOGOUT_REASON_RECOVERY)
                iscsit_ack_from_expstatsn(conn, be32_to_cpu(hdr->exp_statsn));

        /*
         * Immediate commands are executed, well, immediately.
         * Non-Immediate Logout Commands are executed in CmdSN order.
         */
        if (cmd->immediate_cmd) {
                int ret = iscsit_execute_cmd(cmd, 0);

                if (ret < 0)
                        return ret;
        } else {
                cmdsn_ret = iscsit_sequence_cmd(conn, cmd, hdr->cmdsn);
                if (cmdsn_ret == CMDSN_LOWER_THAN_EXP) {
                        logout_remove = 0;
                } else if (cmdsn_ret == CMDSN_ERROR_CANNOT_RECOVER) {
                        return iscsit_add_reject_from_cmd(
                                ISCSI_REASON_PROTOCOL_ERROR,
                                1, 0, buf, cmd);
                }
        }

        return logout_remove;
}

static int iscsit_handle_snack(
        struct iscsi_conn *conn,
        unsigned char *buf)
{
        struct iscsi_snack *hdr;

        hdr                     = (struct iscsi_snack *) buf;
        hdr->flags              &= ~ISCSI_FLAG_CMD_FINAL;

        pr_debug("Got ISCSI_INIT_SNACK, ITT: 0x%08x, ExpStatSN:"
                " 0x%08x, Type: 0x%02x, BegRun: 0x%08x, RunLength: 0x%08x,"
                " CID: %hu\n", hdr->itt, hdr->exp_statsn, hdr->flags,
                        hdr->begrun, hdr->runlength, conn->cid);

        if (!conn->sess->sess_ops->ErrorRecoveryLevel) {
                pr_err("Initiator sent SNACK request while in"
                        " ErrorRecoveryLevel=0.\n");
                return iscsit_add_reject(ISCSI_REASON_PROTOCOL_ERROR, 1,
                                        buf, conn);
        }
        /*
         * SNACK_DATA and SNACK_R2T are both 0,  so check which function to
         * call from inside iscsi_send_recovery_datain_or_r2t().
         */
        switch (hdr->flags & ISCSI_FLAG_SNACK_TYPE_MASK) {
        case 0:
                return iscsit_handle_recovery_datain_or_r2t(conn, buf,
                        hdr->itt,
                        be32_to_cpu(hdr->ttt),
                        be32_to_cpu(hdr->begrun),
                        be32_to_cpu(hdr->runlength));
        case ISCSI_FLAG_SNACK_TYPE_STATUS:
                return iscsit_handle_status_snack(conn, hdr->itt,
                        be32_to_cpu(hdr->ttt),
                        be32_to_cpu(hdr->begrun), be32_to_cpu(hdr->runlength));
        case ISCSI_FLAG_SNACK_TYPE_DATA_ACK:
                return iscsit_handle_data_ack(conn, be32_to_cpu(hdr->ttt),
                        be32_to_cpu(hdr->begrun),
                        be32_to_cpu(hdr->runlength));
        case ISCSI_FLAG_SNACK_TYPE_RDATA:
                /* FIXME: Support R-Data SNACK */
                pr_err("R-Data SNACK Not Supported.\n");
                return iscsit_add_reject(ISCSI_REASON_PROTOCOL_ERROR, 1,
                                        buf, conn);
        default:
                pr_err("Unknown SNACK type 0x%02x, protocol"
                        " error.\n", hdr->flags & 0x0f);
                return iscsit_add_reject(ISCSI_REASON_PROTOCOL_ERROR, 1,
                                        buf, conn);
        }

        return 0;
}

static void iscsit_rx_thread_wait_for_tcp(struct iscsi_conn *conn)
{
        if ((conn->sock->sk->sk_shutdown & SEND_SHUTDOWN) ||
            (conn->sock->sk->sk_shutdown & RCV_SHUTDOWN)) {
                wait_for_completion_interruptible_timeout(
                                        &conn->rx_half_close_comp,
                                        ISCSI_RX_THREAD_TCP_TIMEOUT * HZ);
        }
}

static int iscsit_handle_immediate_data(
        struct iscsi_cmd *cmd,
        unsigned char *buf,
        u32 length)
{
        int iov_ret, rx_got = 0, rx_size = 0;
        u32 checksum, iov_count = 0, padding = 0;
        struct iscsi_conn *conn = cmd->conn;
        struct kvec *iov;

        iov_ret = iscsit_map_iovec(cmd, cmd->iov_data, cmd->write_data_done, length);
        if (iov_ret < 0)
                return IMMEDIATE_DATA_CANNOT_RECOVER;

        rx_size = length;
        iov_count = iov_ret;
        iov = &cmd->iov_data[0];

        padding = ((-length) & 3);
        if (padding != 0) {
                iov[iov_count].iov_base = cmd->pad_bytes;
                iov[iov_count++].iov_len = padding;
                rx_size += padding;
        }

        if (conn->conn_ops->DataDigest) {
                iov[iov_count].iov_base         = &checksum;
                iov[iov_count++].iov_len        = ISCSI_CRC_LEN;
                rx_size += ISCSI_CRC_LEN;
        }

        rx_got = rx_data(conn, &cmd->iov_data[0], iov_count, rx_size);

        iscsit_unmap_iovec(cmd);

        if (rx_got != rx_size) {
                iscsit_rx_thread_wait_for_tcp(conn);
                return IMMEDIATE_DATA_CANNOT_RECOVER;
        }

        if (conn->conn_ops->DataDigest) {
                u32 data_crc;

                data_crc = iscsit_do_crypto_hash_sg(&conn->conn_rx_hash, cmd,
                                                    cmd->write_data_done, length, padding,
                                                    cmd->pad_bytes);

                if (checksum != data_crc) {
                        pr_err("ImmediateData CRC32C DataDigest 0x%08x"
                                " does not match computed 0x%08x\n", checksum,
                                data_crc);

                        if (!conn->sess->sess_ops->ErrorRecoveryLevel) {
                                pr_err("Unable to recover from"
                                        " Immediate Data digest failure while"
                                        " in ERL=0.\n");
                                iscsit_add_reject_from_cmd(
                                                ISCSI_REASON_DATA_DIGEST_ERROR,
                                                1, 0, buf, cmd);
                                return IMMEDIATE_DATA_CANNOT_RECOVER;
                        } else {
                                iscsit_add_reject_from_cmd(
                                                ISCSI_REASON_DATA_DIGEST_ERROR,
                                                0, 0, buf, cmd);
                                return IMMEDIATE_DATA_ERL1_CRC_FAILURE;
                        }
                } else {
                        pr_debug("Got CRC32C DataDigest 0x%08x for"
                                " %u bytes of Immediate Data\n", checksum,
                                length);
                }
        }

        cmd->write_data_done += length;

        if (cmd->write_data_done == cmd->se_cmd.data_length) {
                spin_lock_bh(&cmd->istate_lock);
                cmd->cmd_flags |= ICF_GOT_LAST_DATAOUT;
                cmd->i_state = ISTATE_RECEIVED_LAST_DATAOUT;
                spin_unlock_bh(&cmd->istate_lock);
        }

        return IMMEDIATE_DATA_NORMAL_OPERATION;
}

/*
 *      Called with sess->conn_lock held.
 */
/* #warning iscsi_build_conn_drop_async_message() only sends out on connections
        with active network interface */
static void iscsit_build_conn_drop_async_message(struct iscsi_conn *conn)
{
        struct iscsi_cmd *cmd;
        struct iscsi_conn *conn_p;

        /*
         * Only send a Asynchronous Message on connections whos network
         * interface is still functional.
         */
        list_for_each_entry(conn_p, &conn->sess->sess_conn_list, conn_list) {
                if (conn_p->conn_state == TARG_CONN_STATE_LOGGED_IN) {
                        iscsit_inc_conn_usage_count(conn_p);
                        break;
                }
        }

        if (!conn_p)
                return;

        cmd = iscsit_allocate_cmd(conn_p, GFP_KERNEL);
        if (!cmd) {
                iscsit_dec_conn_usage_count(conn_p);
                return;
        }

        cmd->logout_cid = conn->cid;
        cmd->iscsi_opcode = ISCSI_OP_ASYNC_EVENT;
        cmd->i_state = ISTATE_SEND_ASYNCMSG;

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

        iscsit_add_cmd_to_response_queue(cmd, conn_p, cmd->i_state);
        iscsit_dec_conn_usage_count(conn_p);
}

static int iscsit_send_conn_drop_async_message(
        struct iscsi_cmd *cmd,
        struct iscsi_conn *conn)
{
        struct iscsi_async *hdr;

        cmd->tx_size = ISCSI_HDR_LEN;
        cmd->iscsi_opcode = ISCSI_OP_ASYNC_EVENT;

        hdr                     = (struct iscsi_async *) cmd->pdu;
        hdr->opcode             = ISCSI_OP_ASYNC_EVENT;
        hdr->flags              = ISCSI_FLAG_CMD_FINAL;
        cmd->init_task_tag      = RESERVED_ITT;
        cmd->targ_xfer_tag      = 0xFFFFFFFF;
        put_unaligned_be64(0xFFFFFFFFFFFFFFFFULL, &hdr->rsvd4[0]);
        cmd->stat_sn            = conn->stat_sn++;
        hdr->statsn             = cpu_to_be32(cmd->stat_sn);
        hdr->exp_cmdsn          = cpu_to_be32(conn->sess->exp_cmd_sn);
        hdr->max_cmdsn          = cpu_to_be32(conn->sess->max_cmd_sn);
        hdr->async_event        = ISCSI_ASYNC_MSG_DROPPING_CONNECTION;
        hdr->param1             = cpu_to_be16(cmd->logout_cid);
        hdr->param2             = cpu_to_be16(conn->sess->sess_ops->DefaultTime2Wait);
        hdr->param3             = cpu_to_be16(conn->sess->sess_ops->DefaultTime2Retain);

        if (conn->conn_ops->HeaderDigest) {
                u32 *header_digest = (u32 *)&cmd->pdu[ISCSI_HDR_LEN];

                iscsit_do_crypto_hash_buf(&conn->conn_tx_hash,
                                (unsigned char *)hdr, ISCSI_HDR_LEN,
                                0, NULL, (u8 *)header_digest);

                cmd->tx_size += ISCSI_CRC_LEN;
                pr_debug("Attaching CRC32C HeaderDigest to"
                        " Async Message 0x%08x\n", *header_digest);
        }

        cmd->iov_misc[0].iov_base       = cmd->pdu;
        cmd->iov_misc[0].iov_len        = cmd->tx_size;
        cmd->iov_misc_count             = 1;

        pr_debug("Sending Connection Dropped Async Message StatSN:"
                " 0x%08x, for CID: %hu on CID: %hu\n", cmd->stat_sn,
                        cmd->logout_cid, conn->cid);
        return 0;
}

static void iscsit_tx_thread_wait_for_tcp(struct iscsi_conn *conn)
{
        if ((conn->sock->sk->sk_shutdown & SEND_SHUTDOWN) ||
            (conn->sock->sk->sk_shutdown & RCV_SHUTDOWN)) {
                wait_for_completion_interruptible_timeout(
                                        &conn->tx_half_close_comp,
                                        ISCSI_TX_THREAD_TCP_TIMEOUT * HZ);
        }
}

static int iscsit_send_data_in(
        struct iscsi_cmd *cmd,
        struct iscsi_conn *conn)
{
        int iov_ret = 0, set_statsn = 0;
        u32 iov_count = 0, tx_size = 0;
        struct iscsi_datain datain;
        struct iscsi_datain_req *dr;
        struct iscsi_data_rsp *hdr;
        struct kvec *iov;
        int eodr = 0;
        int ret;

        memset(&datain, 0, sizeof(struct iscsi_datain));
        dr = iscsit_get_datain_values(cmd, &datain);
        if (!dr) {
                pr_err("iscsit_get_datain_values failed for ITT: 0x%08x\n",
                                cmd->init_task_tag);
                return -1;
        }

        /*
         * Be paranoid and double check the logic for now.
         */
        if ((datain.offset + datain.length) > cmd->se_cmd.data_length) {
                pr_err("Command ITT: 0x%08x, datain.offset: %u and"
                        " datain.length: %u exceeds cmd->data_length: %u\n",
                        cmd->init_task_tag, datain.offset, datain.length,
                                cmd->se_cmd.data_length);
                return -1;
        }

        spin_lock_bh(&conn->sess->session_stats_lock);
        conn->sess->tx_data_octets += datain.length;
        if (conn->sess->se_sess->se_node_acl) {
                spin_lock(&conn->sess->se_sess->se_node_acl->stats_lock);
                conn->sess->se_sess->se_node_acl->read_bytes += datain.length;
                spin_unlock(&conn->sess->se_sess->se_node_acl->stats_lock);
        }
        spin_unlock_bh(&conn->sess->session_stats_lock);
        /*
         * Special case for successfully execution w/ both DATAIN
         * and Sense Data.
         */
        if ((datain.flags & ISCSI_FLAG_DATA_STATUS) &&
            (cmd->se_cmd.se_cmd_flags & SCF_TRANSPORT_TASK_SENSE))
                datain.flags &= ~ISCSI_FLAG_DATA_STATUS;
        else {
                if ((dr->dr_complete == DATAIN_COMPLETE_NORMAL) ||
                    (dr->dr_complete == DATAIN_COMPLETE_CONNECTION_RECOVERY)) {
                        iscsit_increment_maxcmdsn(cmd, conn->sess);
                        cmd->stat_sn = conn->stat_sn++;
                        set_statsn = 1;
                } else if (dr->dr_complete ==
                                DATAIN_COMPLETE_WITHIN_COMMAND_RECOVERY)
                        set_statsn = 1;
        }

        hdr     = (struct iscsi_data_rsp *) cmd->pdu;
        memset(hdr, 0, ISCSI_HDR_LEN);
        hdr->opcode             = ISCSI_OP_SCSI_DATA_IN;
        hdr->flags              = datain.flags;
        if (hdr->flags & ISCSI_FLAG_DATA_STATUS) {
                if (cmd->se_cmd.se_cmd_flags & SCF_OVERFLOW_BIT) {
                        hdr->flags |= ISCSI_FLAG_DATA_OVERFLOW;
                        hdr->residual_count = cpu_to_be32(cmd->se_cmd.residual_count);
                } else if (cmd->se_cmd.se_cmd_flags & SCF_UNDERFLOW_BIT) {
                        hdr->flags |= ISCSI_FLAG_DATA_UNDERFLOW;
                        hdr->residual_count = cpu_to_be32(cmd->se_cmd.residual_count);
                }
        }
        hton24(hdr->dlength, datain.length);
        if (hdr->flags & ISCSI_FLAG_DATA_ACK)
                int_to_scsilun(cmd->se_cmd.orig_fe_lun,
                                (struct scsi_lun *)&hdr->lun);
        else
                put_unaligned_le64(0xFFFFFFFFFFFFFFFFULL, &hdr->lun);

        hdr->itt                = cmd->init_task_tag;

        if (hdr->flags & ISCSI_FLAG_DATA_ACK)
                hdr->ttt                = cpu_to_be32(cmd->targ_xfer_tag);
        else
                hdr->ttt                = cpu_to_be32(0xFFFFFFFF);
        if (set_statsn)
                hdr->statsn             = cpu_to_be32(cmd->stat_sn);
        else
                hdr->statsn             = cpu_to_be32(0xFFFFFFFF);

        hdr->exp_cmdsn          = cpu_to_be32(conn->sess->exp_cmd_sn);
        hdr->max_cmdsn          = cpu_to_be32(conn->sess->max_cmd_sn);
        hdr->datasn             = cpu_to_be32(datain.data_sn);
        hdr->offset             = cpu_to_be32(datain.offset);

        iov = &cmd->iov_data[0];
        iov[iov_count].iov_base = cmd->pdu;
        iov[iov_count++].iov_len        = ISCSI_HDR_LEN;
        tx_size += ISCSI_HDR_LEN;

        if (conn->conn_ops->HeaderDigest) {
                u32 *header_digest = (u32 *)&cmd->pdu[ISCSI_HDR_LEN];

                iscsit_do_crypto_hash_buf(&conn->conn_tx_hash,
                                (unsigned char *)hdr, ISCSI_HDR_LEN,
                                0, NULL, (u8 *)header_digest);

                iov[0].iov_len += ISCSI_CRC_LEN;
                tx_size += ISCSI_CRC_LEN;

                pr_debug("Attaching CRC32 HeaderDigest"
                        " for DataIN PDU 0x%08x\n", *header_digest);
        }

        iov_ret = iscsit_map_iovec(cmd, &cmd->iov_data[1], datain.offset, datain.length);
        if (iov_ret < 0)
                return -1;

        iov_count += iov_ret;
        tx_size += datain.length;

        cmd->padding = ((-datain.length) & 3);
        if (cmd->padding) {
                iov[iov_count].iov_base         = cmd->pad_bytes;
                iov[iov_count++].iov_len        = cmd->padding;
                tx_size += cmd->padding;

                pr_debug("Attaching %u padding bytes\n",
                                cmd->padding);
        }
        if (conn->conn_ops->DataDigest) {
                cmd->data_crc = iscsit_do_crypto_hash_sg(&conn->conn_tx_hash, cmd,
                         datain.offset, datain.length, cmd->padding, cmd->pad_bytes);

                iov[iov_count].iov_base = &cmd->data_crc;
                iov[iov_count++].iov_len = ISCSI_CRC_LEN;
                tx_size += ISCSI_CRC_LEN;

                pr_debug("Attached CRC32C DataDigest %d bytes, crc"
                        " 0x%08x\n", datain.length+cmd->padding, cmd->data_crc);
        }

        cmd->iov_data_count = iov_count;
        cmd->tx_size = tx_size;

        pr_debug("Built DataIN ITT: 0x%08x, StatSN: 0x%08x,"
                " DataSN: 0x%08x, Offset: %u, Length: %u, CID: %hu\n",
                cmd->init_task_tag, ntohl(hdr->statsn), ntohl(hdr->datasn),
                ntohl(hdr->offset), datain.length, conn->cid);

        /* sendpage is preferred but can't insert markers */
        if (!conn->conn_ops->IFMarker)
                ret = iscsit_fe_sendpage_sg(cmd, conn);
        else
                ret = iscsit_send_tx_data(cmd, conn, 0);

        iscsit_unmap_iovec(cmd);

        if (ret < 0) {
                iscsit_tx_thread_wait_for_tcp(conn);
                return ret;
        }

        if (dr->dr_complete) {
                eodr = (cmd->se_cmd.se_cmd_flags & SCF_TRANSPORT_TASK_SENSE) ?
                                2 : 1;
                iscsit_free_datain_req(cmd, dr);
        }

        return eodr;
}

static int iscsit_send_logout_response(
        struct iscsi_cmd *cmd,
        struct iscsi_conn *conn)
{
        int niov = 0, tx_size;
        struct iscsi_conn *logout_conn = NULL;
        struct iscsi_conn_recovery *cr = NULL;
        struct iscsi_session *sess = conn->sess;
        struct kvec *iov;
        struct iscsi_logout_rsp *hdr;
        /*
         * The actual shutting down of Sessions and/or Connections
         * for CLOSESESSION and CLOSECONNECTION Logout Requests
         * is done in scsi_logout_post_handler().
         */
        switch (cmd->logout_reason) {
        case ISCSI_LOGOUT_REASON_CLOSE_SESSION:
                pr_debug("iSCSI session logout successful, setting"
                        " logout response to ISCSI_LOGOUT_SUCCESS.\n");
                cmd->logout_response = ISCSI_LOGOUT_SUCCESS;
                break;
        case ISCSI_LOGOUT_REASON_CLOSE_CONNECTION:
                if (cmd->logout_response == ISCSI_LOGOUT_CID_NOT_FOUND)
                        break;
                /*
                 * For CLOSECONNECTION logout requests carrying
                 * a matching logout CID -> local CID, the reference
                 * for the local CID will have been incremented in
                 * iscsi_logout_closeconnection().
                 *
                 * For CLOSECONNECTION logout requests carrying
                 * a different CID than the connection it arrived
                 * on, the connection responding to cmd->logout_cid
                 * is stopped in iscsit_logout_post_handler_diffcid().
                 */

                pr_debug("iSCSI CID: %hu logout on CID: %hu"
                        " successful.\n", cmd->logout_cid, conn->cid);
                cmd->logout_response = ISCSI_LOGOUT_SUCCESS;
                break;
        case ISCSI_LOGOUT_REASON_RECOVERY:
                if ((cmd->logout_response == ISCSI_LOGOUT_RECOVERY_UNSUPPORTED) ||
                    (cmd->logout_response == ISCSI_LOGOUT_CLEANUP_FAILED))
                        break;
                /*
                 * If the connection is still active from our point of view
                 * force connection recovery to occur.
                 */
                logout_conn = iscsit_get_conn_from_cid_rcfr(sess,
                                cmd->logout_cid);
                if (logout_conn) {
                        iscsit_connection_reinstatement_rcfr(logout_conn);
                        iscsit_dec_conn_usage_count(logout_conn);
                }

                cr = iscsit_get_inactive_connection_recovery_entry(
                                conn->sess, cmd->logout_cid);
                if (!cr) {
                        pr_err("Unable to locate CID: %hu for"
                        " REMOVECONNFORRECOVERY Logout Request.\n",
                                cmd->logout_cid);
                        cmd->logout_response = ISCSI_LOGOUT_CID_NOT_FOUND;
                        break;
                }

                iscsit_discard_cr_cmds_by_expstatsn(cr, cmd->exp_stat_sn);

                pr_debug("iSCSI REMOVECONNFORRECOVERY logout"
                        " for recovery for CID: %hu on CID: %hu successful.\n",
                                cmd->logout_cid, conn->cid);
                cmd->logout_response = ISCSI_LOGOUT_SUCCESS;
                break;
        default:
                pr_err("Unknown cmd->logout_reason: 0x%02x\n",
                                cmd->logout_reason);
                return -1;
        }

        tx_size = ISCSI_HDR_LEN;
        hdr                     = (struct iscsi_logout_rsp *)cmd->pdu;
        memset(hdr, 0, ISCSI_HDR_LEN);
        hdr->opcode             = ISCSI_OP_LOGOUT_RSP;
        hdr->flags              |= ISCSI_FLAG_CMD_FINAL;
        hdr->response           = cmd->logout_response;
        hdr->itt                = cmd->init_task_tag;
        cmd->stat_sn            = conn->stat_sn++;
        hdr->statsn             = cpu_to_be32(cmd->stat_sn);

        iscsit_increment_maxcmdsn(cmd, conn->sess);
        hdr->exp_cmdsn          = cpu_to_be32(conn->sess->exp_cmd_sn);
        hdr->max_cmdsn          = cpu_to_be32(conn->sess->max_cmd_sn);

        iov = &cmd->iov_misc[0];
        iov[niov].iov_base      = cmd->pdu;
        iov[niov++].iov_len     = ISCSI_HDR_LEN;

        if (conn->conn_ops->HeaderDigest) {
                u32 *header_digest = (u32 *)&cmd->pdu[ISCSI_HDR_LEN];

                iscsit_do_crypto_hash_buf(&conn->conn_tx_hash,
                                (unsigned char *)hdr, ISCSI_HDR_LEN,
                                0, NULL, (u8 *)header_digest);

                iov[0].iov_len += ISCSI_CRC_LEN;
                tx_size += ISCSI_CRC_LEN;
                pr_debug("Attaching CRC32C HeaderDigest to"
                        " Logout Response 0x%08x\n", *header_digest);
        }
        cmd->iov_misc_count = niov;
        cmd->tx_size = tx_size;

        pr_debug("Sending Logout Response ITT: 0x%08x StatSN:"
                " 0x%08x Response: 0x%02x CID: %hu on CID: %hu\n",
                cmd->init_task_tag, cmd->stat_sn, hdr->response,
                cmd->logout_cid, conn->cid);

        return 0;
}

/*
 *      Unsolicited NOPIN, either requesting a response or not.
 */
static int iscsit_send_unsolicited_nopin(
        struct iscsi_cmd *cmd,
        struct iscsi_conn *conn,
        int want_response)
{
        int tx_size = ISCSI_HDR_LEN;
        struct iscsi_nopin *hdr;
        int ret;

        hdr                     = (struct iscsi_nopin *) cmd->pdu;
        memset(hdr, 0, ISCSI_HDR_LEN);
        hdr->opcode             = ISCSI_OP_NOOP_IN;
        hdr->flags              |= ISCSI_FLAG_CMD_FINAL;
        hdr->itt                = cmd->init_task_tag;
        hdr->ttt                = cpu_to_be32(cmd->targ_xfer_tag);
        cmd->stat_sn            = conn->stat_sn;
        hdr->statsn             = cpu_to_be32(cmd->stat_sn);
        hdr->exp_cmdsn          = cpu_to_be32(conn->sess->exp_cmd_sn);
        hdr->max_cmdsn          = cpu_to_be32(conn->sess->max_cmd_sn);

        if (conn->conn_ops->HeaderDigest) {
                u32 *header_digest = (u32 *)&cmd->pdu[ISCSI_HDR_LEN];

                iscsit_do_crypto_hash_buf(&conn->conn_tx_hash,
                                (unsigned char *)hdr, ISCSI_HDR_LEN,
                                0, NULL, (u8 *)header_digest);

                tx_size += ISCSI_CRC_LEN;
                pr_debug("Attaching CRC32C HeaderDigest to"
                        " NopIN 0x%08x\n", *header_digest);
        }

        cmd->iov_misc[0].iov_base       = cmd->pdu;
        cmd->iov_misc[0].iov_len        = tx_size;
        cmd->iov_misc_count     = 1;
        cmd->tx_size            = tx_size;

        pr_debug("Sending Unsolicited NOPIN TTT: 0x%08x StatSN:"
                " 0x%08x CID: %hu\n", hdr->ttt, cmd->stat_sn, conn->cid);

        ret = iscsit_send_tx_data(cmd, conn, 1);
        if (ret < 0) {
                iscsit_tx_thread_wait_for_tcp(conn);
                return ret;
        }

        spin_lock_bh(&cmd->istate_lock);
        cmd->i_state = want_response ?
                ISTATE_SENT_NOPIN_WANT_RESPONSE : ISTATE_SENT_STATUS;
        spin_unlock_bh(&cmd->istate_lock);

        return 0;
}

static int iscsit_send_nopin_response(
        struct iscsi_cmd *cmd,
        struct iscsi_conn *conn)
{
        int niov = 0, tx_size;
        u32 padding = 0;
        struct kvec *iov;
        struct iscsi_nopin *hdr;

        tx_size = ISCSI_HDR_LEN;
        hdr                     = (struct iscsi_nopin *) cmd->pdu;
        memset(hdr, 0, ISCSI_HDR_LEN);
        hdr->opcode             = ISCSI_OP_NOOP_IN;
        hdr->flags              |= ISCSI_FLAG_CMD_FINAL;
        hton24(hdr->dlength, cmd->buf_ptr_size);
        put_unaligned_le64(0xFFFFFFFFFFFFFFFFULL, &hdr->lun);
        hdr->itt                = cmd->init_task_tag;
        hdr->ttt                = cpu_to_be32(cmd->targ_xfer_tag);
        cmd->stat_sn            = conn->stat_sn++;
        hdr->statsn             = cpu_to_be32(cmd->stat_sn);

        iscsit_increment_maxcmdsn(cmd, conn->sess);
        hdr->exp_cmdsn          = cpu_to_be32(conn->sess->exp_cmd_sn);
        hdr->max_cmdsn          = cpu_to_be32(conn->sess->max_cmd_sn);

        iov = &cmd->iov_misc[0];
        iov[niov].iov_base      = cmd->pdu;
        iov[niov++].iov_len     = ISCSI_HDR_LEN;

        if (conn->conn_ops->HeaderDigest) {
                u32 *header_digest = (u32 *)&cmd->pdu[ISCSI_HDR_LEN];

                iscsit_do_crypto_hash_buf(&conn->conn_tx_hash,
                                (unsigned char *)hdr, ISCSI_HDR_LEN,
                                0, NULL, (u8 *)header_digest);

                iov[0].iov_len += ISCSI_CRC_LEN;
                tx_size += ISCSI_CRC_LEN;
                pr_debug("Attaching CRC32C HeaderDigest"
                        " to NopIn 0x%08x\n", *header_digest);
        }

        /*
         * NOPOUT Ping Data is attached to struct iscsi_cmd->buf_ptr.
         * NOPOUT DataSegmentLength is at struct iscsi_cmd->buf_ptr_size.
         */
        if (cmd->buf_ptr_size) {
                iov[niov].iov_base      = cmd->buf_ptr;
                iov[niov++].iov_len     = cmd->buf_ptr_size;
                tx_size += cmd->buf_ptr_size;

                pr_debug("Echoing back %u bytes of ping"
                        " data.\n", cmd->buf_ptr_size);

                padding = ((-cmd->buf_ptr_size) & 3);
                if (padding != 0) {
                        iov[niov].iov_base = &cmd->pad_bytes;
                        iov[niov++].iov_len = padding;
                        tx_size += padding;
                        pr_debug("Attaching %u additional"
                                " padding bytes.\n", padding);
                }
                if (conn->conn_ops->DataDigest) {
                        iscsit_do_crypto_hash_buf(&conn->conn_tx_hash,
                                cmd->buf_ptr, cmd->buf_ptr_size,
                                padding, (u8 *)&cmd->pad_bytes,
                                (u8 *)&cmd->data_crc);

                        iov[niov].iov_base = &cmd->data_crc;
                        iov[niov++].iov_len = ISCSI_CRC_LEN;
                        tx_size += ISCSI_CRC_LEN;
                        pr_debug("Attached DataDigest for %u"
                                " bytes of ping data, CRC 0x%08x\n",
                                cmd->buf_ptr_size, cmd->data_crc);
                }
        }

        cmd->iov_misc_count = niov;
        cmd->tx_size = tx_size;

        pr_debug("Sending NOPIN Response ITT: 0x%08x, TTT:"
                " 0x%08x, StatSN: 0x%08x, Length %u\n", cmd->init_task_tag,
                cmd->targ_xfer_tag, cmd->stat_sn, cmd->buf_ptr_size);

        return 0;
}

static int iscsit_send_r2t(
        struct iscsi_cmd *cmd,
        struct iscsi_conn *conn)
{
        int tx_size = 0;
        struct iscsi_r2t *r2t;
        struct iscsi_r2t_rsp *hdr;
        int ret;

        r2t = iscsit_get_r2t_from_list(cmd);
        if (!r2t)
                return -1;

        hdr                     = (struct iscsi_r2t_rsp *) cmd->pdu;
        memset(hdr, 0, ISCSI_HDR_LEN);
        hdr->opcode             = ISCSI_OP_R2T;
        hdr->flags              |= ISCSI_FLAG_CMD_FINAL;
        int_to_scsilun(cmd->se_cmd.orig_fe_lun,
                        (struct scsi_lun *)&hdr->lun);
        hdr->itt                = cmd->init_task_tag;
        spin_lock_bh(&conn->sess->ttt_lock);
        r2t->targ_xfer_tag      = conn->sess->targ_xfer_tag++;
        if (r2t->targ_xfer_tag == 0xFFFFFFFF)
                r2t->targ_xfer_tag = conn->sess->targ_xfer_tag++;
        spin_unlock_bh(&conn->sess->ttt_lock);
        hdr->ttt                = cpu_to_be32(r2t->targ_xfer_tag);
        hdr->statsn             = cpu_to_be32(conn->stat_sn);
        hdr->exp_cmdsn          = cpu_to_be32(conn->sess->exp_cmd_sn);
        hdr->max_cmdsn          = cpu_to_be32(conn->sess->max_cmd_sn);
        hdr->r2tsn              = cpu_to_be32(r2t->r2t_sn);
        hdr->data_offset        = cpu_to_be32(r2t->offset);
        hdr->data_length        = cpu_to_be32(r2t->xfer_len);

        cmd->iov_misc[0].iov_base       = cmd->pdu;
        cmd->iov_misc[0].iov_len        = ISCSI_HDR_LEN;
        tx_size += ISCSI_HDR_LEN;

        if (conn->conn_ops->HeaderDigest) {
                u32 *header_digest = (u32 *)&cmd->pdu[ISCSI_HDR_LEN];

                iscsit_do_crypto_hash_buf(&conn->conn_tx_hash,
                                (unsigned char *)hdr, ISCSI_HDR_LEN,
                                0, NULL, (u8 *)header_digest);

                cmd->iov_misc[0].iov_len += ISCSI_CRC_LEN;
                tx_size += ISCSI_CRC_LEN;
                pr_debug("Attaching CRC32 HeaderDigest for R2T"
                        " PDU 0x%08x\n", *header_digest);
        }

        pr_debug("Built %sR2T, ITT: 0x%08x, TTT: 0x%08x, StatSN:"
                " 0x%08x, R2TSN: 0x%08x, Offset: %u, DDTL: %u, CID: %hu\n",
                (!r2t->recovery_r2t) ? "" : "Recovery ", cmd->init_task_tag,
                r2t->targ_xfer_tag, ntohl(hdr->statsn), r2t->r2t_sn,
                        r2t->offset, r2t->xfer_len, conn->cid);

        cmd->iov_misc_count = 1;
        cmd->tx_size = tx_size;

        spin_lock_bh(&cmd->r2t_lock);
        r2t->sent_r2t = 1;
        spin_unlock_bh(&cmd->r2t_lock);

        ret = iscsit_send_tx_data(cmd, conn, 1);
        if (ret < 0) {
                iscsit_tx_thread_wait_for_tcp(conn);
                return ret;
        }

        spin_lock_bh(&cmd->dataout_timeout_lock);
        iscsit_start_dataout_timer(cmd, conn);
        spin_unlock_bh(&cmd->dataout_timeout_lock);

        return 0;
}

/*
 *      @recovery: If called from iscsi_task_reassign_complete_write() for
 *              connection recovery.
 */
int iscsit_build_r2ts_for_cmd(
        struct iscsi_cmd *cmd,
        struct iscsi_conn *conn,
        bool recovery)
{
        int first_r2t = 1;
        u32 offset = 0, xfer_len = 0;

        spin_lock_bh(&cmd->r2t_lock);
        if (cmd->cmd_flags & ICF_SENT_LAST_R2T) {
                spin_unlock_bh(&cmd->r2t_lock);
                return 0;
        }

        if (conn->sess->sess_ops->DataSequenceInOrder &&
            !recovery)
                cmd->r2t_offset = max(cmd->r2t_offset, cmd->write_data_done);

        while (cmd->outstanding_r2ts < conn->sess->sess_ops->MaxOutstandingR2T) {
                if (conn->sess->sess_ops->DataSequenceInOrder) {
                        offset = cmd->r2t_offset;

                        if (first_r2t && recovery) {
                                int new_data_end = offset +
                                        conn->sess->sess_ops->MaxBurstLength -
                                        cmd->next_burst_len;

                                if (new_data_end > cmd->se_cmd.data_length)
                                        xfer_len = cmd->se_cmd.data_length - offset;
                                else
                                        xfer_len =
                                                conn->sess->sess_ops->MaxBurstLength -
                                                cmd->next_burst_len;
                        } else {
                                int new_data_end = offset +
                                        conn->sess->sess_ops->MaxBurstLength;

                                if (new_data_end > cmd->se_cmd.data_length)
                                        xfer_len = cmd->se_cmd.data_length - offset;
                                else
                                        xfer_len = conn->sess->sess_ops->MaxBurstLength;
                        }
                        cmd->r2t_offset += xfer_len;

                        if (cmd->r2t_offset == cmd->se_cmd.data_length)
                                cmd->cmd_flags |= ICF_SENT_LAST_R2T;
                } else {
                        struct iscsi_seq *seq;

                        seq = iscsit_get_seq_holder_for_r2t(cmd);