// SPDX-License-Identifier: GPL-2.0-or-later
/*******************************************************************************
 * This file contains main functions related to the iSCSI Target Core Driver.
 *
 * (c) Copyright 2007-2013 Datera, Inc.
 *
 * Author: Nicholas A. Bellinger <nab@linux-iscsi.org>
 *
 ******************************************************************************/

#include <crypto/hash.h>
#include <linux/string.h>
#include <linux/kthread.h>
#include <linux/completion.h>
#include <linux/module.h>
#include <linux/vmalloc.h>
#include <linux/idr.h>
#include <linux/delay.h>
#include <linux/sched/signal.h>
#include <asm/unaligned.h>
#include <linux/inet.h>
#include <net/ipv6.h>
#include <scsi/scsi_proto.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/iscsi/iscsi_target_core.h>
#include "iscsi_target_parameters.h"
#include "iscsi_target_seq_pdu_list.h"
#include "iscsi_target_datain_values.h"
#include "iscsi_target_erl0.h"
#include "iscsi_target_erl1.h"
#include "iscsi_target_erl2.h"
#include "iscsi_target_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 <target/iscsi/iscsi_target_stat.h>

#include <target/iscsi/iscsi_transport.h>

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

static struct idr tiqn_idr;
DEFINE_IDA(sess_ida);
struct mutex auth_id_lock;

struct iscsit_global *iscsit_global;

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 *,
                        struct iscsi_scsi_req *, u32);

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(*tiqn), GFP_KERNEL);
        if (!tiqn)
                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);

        tiqn->tiqn_state = TIQN_STATE_ACTIVE;

        idr_preload(GFP_KERNEL);
        spin_lock(&tiqn_lock);

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

        spin_unlock(&tiqn_lock);
        idr_preload_end();

        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;
        }
        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 = down_interruptible(&tpg->np_login_sem);
        if (ret != 0)
                return -1;

        spin_lock_bh(&tpg->tpg_state_lock);
        if (tpg->tpg_state != TPG_STATE_ACTIVE) {
                spin_unlock_bh(&tpg->tpg_state_lock);
                up(&tpg->np_login_sem);
                return -1;
        }
        spin_unlock_bh(&tpg->tpg_state_lock);

        return 0;
}

void iscsit_login_kref_put(struct kref *kref)
{
        struct iscsi_tpg_np *tpg_np = container_of(kref,
                                struct iscsi_tpg_np, tpg_np_kref);

        complete(&tpg_np->tpg_np_comp);
}

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

        up(&tpg->np_login_sem);

        if (tpg_np)
                kref_put(&tpg_np->tpg_np_kref, iscsit_login_kref_put);

        if (tiqn)
                iscsit_put_tiqn_for_login(tiqn);

        return 0;
}

bool iscsit_check_np_match(
        struct sockaddr_storage *sockaddr,
        struct iscsi_np *np,
        int network_transport)
{
        struct sockaddr_in *sock_in, *sock_in_e;
        struct sockaddr_in6 *sock_in6, *sock_in6_e;
        bool ip_match = false;
        u16 port, port_e;

        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 = true;

                port = ntohs(sock_in6->sin6_port);
                port_e = ntohs(sock_in6_e->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 = true;

                port = ntohs(sock_in->sin_port);
                port_e = ntohs(sock_in_e->sin_port);
        }

        if (ip_match && (port_e == port) &&
            (np->np_network_transport == network_transport))
                return true;

        return false;
}

static struct iscsi_np *iscsit_get_np(
        struct sockaddr_storage *sockaddr,
        int network_transport)
{
        struct iscsi_np *np;
        bool match;

        lockdep_assert_held(&np_lock);

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

                match = iscsit_check_np_match(sockaddr, np, network_transport);
                if (match) {
                        /*
                         * 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_bh(&np->np_thread_lock);
                        return np;
                }
                spin_unlock_bh(&np->np_thread_lock);
        }

        return NULL;
}

struct iscsi_np *iscsit_add_np(
        struct sockaddr_storage *sockaddr,
        int network_transport)
{
        struct iscsi_np *np;
        int ret;

        mutex_lock(&np_lock);

        /*
         * Locate the existing struct iscsi_np if already active..
         */
        np = iscsit_get_np(sockaddr, network_transport);
        if (np) {
                mutex_unlock(&np_lock);
                return np;
        }

        np = kzalloc(sizeof(*np), GFP_KERNEL);
        if (!np) {
                mutex_unlock(&np_lock);
                return ERR_PTR(-ENOMEM);
        }

        np->np_flags |= NPF_IP_NETWORK;
        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);

        timer_setup(&np->np_login_timer, iscsi_handle_login_thread_timeout, 0);

        ret = iscsi_target_setup_login_socket(np, sockaddr);
        if (ret != 0) {
                kfree(np);
                mutex_unlock(&np_lock);
                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);
                mutex_unlock(&np_lock);
                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;
        np->np_thread_state = ISCSI_NP_THREAD_ACTIVE;

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

        pr_debug("CORE[0] - Added Network Portal: %pISpc on %s\n",
                &np->np_sockaddr, np->np_transport->name);

        return np;
}

int iscsit_reset_np_thread(
        struct iscsi_np *np,
        struct iscsi_tpg_np *tpg_np,
        struct iscsi_portal_group *tpg,
        bool shutdown)
{
        spin_lock_bh(&np->np_thread_lock);
        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;
        atomic_inc(&np->np_reset_count);

        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);

        if (tpg_np && shutdown) {
                kref_put(&tpg_np->tpg_np_kref, iscsit_login_kref_put);

                wait_for_completion(&tpg_np->tpg_np_comp);
        }

        return 0;
}

static void iscsit_free_np(struct iscsi_np *np)
{
        if (np->np_socket)
                sock_release(np->np_socket);
}

int iscsit_del_np(struct iscsi_np *np)
{
        spin_lock_bh(&np->np_thread_lock);
        np->np_exports--;
        if (np->np_exports) {
                np->enabled = true;
                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);
                np->np_thread = NULL;
        }

        np->np_transport->iscsit_free_np(np);

        mutex_lock(&np_lock);
        list_del(&np->np_list);
        mutex_unlock(&np_lock);

        pr_debug("CORE[0] - Removed Network Portal: %pISpc on %s\n",
                &np->np_sockaddr, np->np_transport->name);

        iscsit_put_transport(np->np_transport);
        kfree(np);
        return 0;
}

static void iscsit_get_rx_pdu(struct iscsi_conn *);

int iscsit_queue_rsp(struct iscsi_conn *conn, struct iscsi_cmd *cmd)
{
        return iscsit_add_cmd_to_response_queue(cmd, cmd->conn, cmd->i_state);
}
EXPORT_SYMBOL(iscsit_queue_rsp);

void iscsit_aborted_task(struct iscsi_conn *conn, struct iscsi_cmd *cmd)
{
        spin_lock_bh(&conn->cmd_lock);
        if (!list_empty(&cmd->i_conn_node) &&
            !(cmd->se_cmd.transport_state & CMD_T_FABRIC_STOP))
                list_del_init(&cmd->i_conn_node);
        spin_unlock_bh(&conn->cmd_lock);

        __iscsit_free_cmd(cmd, true);
}
EXPORT_SYMBOL(iscsit_aborted_task);

static void iscsit_do_crypto_hash_buf(struct ahash_request *, const void *,
                                      u32, u32, const void *, void *);
static void iscsit_tx_thread_wait_for_tcp(struct iscsi_conn *);

static int
iscsit_xmit_nondatain_pdu(struct iscsi_conn *conn, struct iscsi_cmd *cmd,
                          const void *data_buf, u32 data_buf_len)
{
        struct iscsi_hdr *hdr = (struct iscsi_hdr *)cmd->pdu;
        struct kvec *iov;
        u32 niov = 0, tx_size = ISCSI_HDR_LEN;
        int ret;

        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, hdr,
                                          ISCSI_HDR_LEN, 0, NULL,
                                          header_digest);

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

        if (data_buf_len) {
                u32 padding = ((-data_buf_len) & 3);

                iov[niov].iov_base      = (void *)data_buf;
                iov[niov++].iov_len     = data_buf_len;
                tx_size += data_buf_len;

                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,
                                                  data_buf, data_buf_len,
                                                  padding, &cmd->pad_bytes,
                                                  &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 opcode 0x%x, CRC 0x%08x\n",
                                 data_buf_len, hdr->opcode, cmd->data_crc);
                }
        }

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

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

        return 0;
}

static int iscsit_map_iovec(struct iscsi_cmd *cmd, struct kvec *iov, int nvec,
                            u32 data_offset, u32 data_length);
static void iscsit_unmap_iovec(struct iscsi_cmd *);
static u32 iscsit_do_crypto_hash_sg(struct ahash_request *, struct iscsi_cmd *,
                                    u32, u32, u32, u8 *);
static int
iscsit_xmit_datain_pdu(struct iscsi_conn *conn, struct iscsi_cmd *cmd,
                       const struct iscsi_datain *datain)
{
        struct kvec *iov;
        u32 iov_count = 0, tx_size = 0;
        int ret, iov_ret;

        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, cmd->pdu,
                                          ISCSI_HDR_LEN, 0, NULL,
                                          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[iov_count],
                                   cmd->orig_iov_data_count - (iov_count + 2),
                                   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;

        ret = iscsit_fe_sendpage_sg(cmd, conn);

        iscsit_unmap_iovec(cmd);

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

        return 0;
}

static int iscsit_xmit_pdu(struct iscsi_conn *conn, struct iscsi_cmd *cmd,
                           struct iscsi_datain_req *dr, const void *buf,
                           u32 buf_len)
{
        if (dr)
                return iscsit_xmit_datain_pdu(conn, cmd, buf);
        else
                return iscsit_xmit_nondatain_pdu(conn, cmd, buf, buf_len);
}

static enum target_prot_op iscsit_get_sup_prot_ops(struct iscsi_conn *conn)
{
        return TARGET_PROT_NORMAL;
}

static struct iscsit_transport iscsi_target_transport = {
        .name                   = "iSCSI/TCP",
        .transport_type         = ISCSI_TCP,
        .rdma_shutdown          = false,
        .owner                  = NULL,
        .iscsit_setup_np        = iscsit_setup_np,
        .iscsit_accept_np       = iscsit_accept_np,
        .iscsit_free_np         = iscsit_free_np,
        .iscsit_get_login_rx    = iscsit_get_login_rx,
        .iscsit_put_login_tx    = iscsit_put_login_tx,
        .iscsit_get_dataout     = iscsit_build_r2ts_for_cmd,
        .iscsit_immediate_queue = iscsit_immediate_queue,
        .iscsit_response_queue  = iscsit_response_queue,
        .iscsit_queue_data_in   = iscsit_queue_rsp,
        .iscsit_queue_status    = iscsit_queue_rsp,
        .iscsit_aborted_task    = iscsit_aborted_task,
        .iscsit_xmit_pdu        = iscsit_xmit_pdu,
        .iscsit_get_rx_pdu      = iscsit_get_rx_pdu,
        .iscsit_get_sup_prot_ops = iscsit_get_sup_prot_ops,
};

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

        pr_debug("iSCSI-Target "ISCSIT_VERSION"\n");
        iscsit_global = kzalloc(sizeof(*iscsit_global), GFP_KERNEL);
        if (!iscsit_global)
                return -1;

        spin_lock_init(&iscsit_global->ts_bitmap_lock);
        mutex_init(&auth_id_lock);
        idr_init(&tiqn_idr);

        ret = target_register_template(&iscsi_ops);
        if (ret)
                goto out;

        size = BITS_TO_LONGS(ISCSIT_BITMAP_BITS) * sizeof(long);
        iscsit_global->ts_bitmap = vzalloc(size);
        if (!iscsit_global->ts_bitmap)
                goto configfs_out;

        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("Unable to kmem_cache_create() for"
                                " lio_qr_cache\n");
                goto bitmap_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;
        }

        iscsit_register_transport(&iscsi_target_transport);

        if (iscsit_load_discovery_tpg() < 0)
                goto r2t_out;

        return ret;
r2t_out:
        iscsit_unregister_transport(&iscsi_target_transport);
        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);
bitmap_out:
        vfree(iscsit_global->ts_bitmap);
configfs_out:
        /* XXX: this probably wants it to be it's own unwind step.. */
        if (iscsit_global->discovery_tpg)
                iscsit_tpg_disable_portal_group(iscsit_global->discovery_tpg, 1);
        target_unregister_template(&iscsi_ops);
out:
        kfree(iscsit_global);
        return -ENOMEM;
}

static void __exit iscsi_target_cleanup_module(void)
{
        iscsit_release_discovery_tpg();
        iscsit_unregister_transport(&iscsi_target_transport);
        kmem_cache_destroy(lio_qr_cache);
        kmem_cache_destroy(lio_dr_cache);
        kmem_cache_destroy(lio_ooo_cache);
        kmem_cache_destroy(lio_r2t_cache);

        /*
         * Shutdown discovery sessions and disable discovery TPG
         */
        if (iscsit_global->discovery_tpg)
                iscsit_tpg_disable_portal_group(iscsit_global->discovery_tpg, 1);

        target_unregister_template(&iscsi_ops);

        vfree(iscsit_global->ts_bitmap);
        kfree(iscsit_global);
}

int iscsit_add_reject(
        struct iscsi_conn *conn,
        u8 reason,
        unsigned char *buf)
{
        struct iscsi_cmd *cmd;

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

        cmd->iscsi_opcode = ISCSI_OP_REJECT;
        cmd->reject_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_free_cmd(cmd, false);
                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);

        return -1;
}
EXPORT_SYMBOL(iscsit_add_reject);

static int iscsit_add_reject_from_cmd(
        struct iscsi_cmd *cmd,
        u8 reason,
        bool add_to_conn,
        unsigned char *buf)
{
        struct iscsi_conn *conn;
        const bool do_put = cmd->se_cmd.se_tfo != NULL;

        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;
        cmd->reject_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_free_cmd(cmd, false);
                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);
        /*
         * Perform the kref_put now if se_cmd has already been setup by
         * scsit_setup_scsi_cmd()
         */
        if (do_put) {
                pr_debug("iscsi reject: calling target_put_sess_cmd >>>>>>\n");
                target_put_sess_cmd(&cmd->se_cmd);
        }
        return -1;
}

static int iscsit_add_reject_cmd(struct iscsi_cmd *cmd, u8 reason,
                                 unsigned char *buf)
{
        return iscsit_add_reject_from_cmd(cmd, reason, true, buf);
}

int iscsit_reject_cmd(struct iscsi_cmd *cmd, u8 reason, unsigned char *buf)
{
        return iscsit_add_reject_from_cmd(cmd, reason, false, buf);
}
EXPORT_SYMBOL(iscsit_reject_cmd);

/*
 * 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, int nvec,
                            u32 data_offset, u32 data_length)
{
        u32 i = 0, orig_data_length = data_length;
        struct scatterlist *sg;
        unsigned int page_off;

        /*
         * We know each entry in t_data_sg contains a page.
         */
        u32 ent = data_offset / PAGE_SIZE;

        if (!data_length)
                return 0;

        if (ent >= cmd->se_cmd.t_data_nents) {
                pr_err("Initial page entry out-of-bounds\n");
                goto overflow;
        }

        sg = &cmd->se_cmd.t_data_sg[ent];
        page_off = (data_offset % PAGE_SIZE);

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

        while (data_length) {
                u32 cur_len;

                if (WARN_ON_ONCE(!sg || i >= nvec))
                        goto overflow;

                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;

overflow:
        pr_err("offset %d + length %d overflow; %d/%d; sg-list:\n",
               data_offset, orig_data_length, i, nvec);
        for_each_sg(cmd->se_cmd.t_data_sg, sg,
                    cmd->se_cmd.t_data_nents, i) {
                pr_err("[%d] off %d len %d\n",
                       i, sg->offset, sg->length);
        }
        return -1;
}

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)
{
        LIST_HEAD(ack_list);
        struct iscsi_cmd *cmd, *cmd_p;

        conn->exp_statsn = exp_statsn;

        if (conn->sess->sess_ops->RDMAExtensions)
                return;

        spin_lock_bh(&conn->cmd_lock);
        list_for_each_entry_safe(cmd, cmd_p, &conn->conn_cmd_list, i_conn_node) {
                spin_lock(&cmd->istate_lock);
                if ((cmd->i_state == ISTATE_SENT_STATUS) &&
                    iscsi_sna_lt(cmd->stat_sn, exp_statsn)) {
                        cmd->i_state = ISTATE_REMOVE;
                        spin_unlock(&cmd->istate_lock);
                        list_move_tail(&cmd->i_conn_node, &ack_list);
                        continue;
                }
                spin_unlock(&cmd->istate_lock);
        }
        spin_unlock_bh(&conn->cmd_lock);

        list_for_each_entry_safe(cmd, cmd_p, &ack_list, i_conn_node) {
                list_del_init(&cmd->i_conn_node);
                iscsit_free_cmd(cmd, false);
        }
}

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 = kcalloc(iov_count, sizeof(*cmd->iov_data), GFP_KERNEL);
        if (!cmd->iov_data)
                return -ENOMEM;

        cmd->orig_iov_data_count = iov_count;
        return 0;
}

int iscsit_setup_scsi_cmd(struct iscsi_conn *conn, struct iscsi_cmd *cmd,
                          unsigned char *buf)
{
        int data_direction, payload_length;
        struct iscsi_scsi_req *hdr;
        int iscsi_task_attr;

        int sam_task_attr;

        atomic_long_inc(&conn->sess->cmd_pdus);

        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_cmd(cmd,
                                             ISCSI_REASON_BOOKMARK_INVALID, buf);
        }

        if (((hdr->flags & ISCSI_FLAG_CMD_READ) ||
             (hdr->flags & ISCSI_FLAG_CMD_WRITE)) && !hdr->data_length) {
                /*
                 * From RFC-3720 Section 10.3.1:
                 *
                 * "Either or both of R and W MAY be 1 when either the
                 *  Expected Data Transfer Length and/or Bidirectional Read
                 *  Expected Data Transfer Length are 0"
                 *
                 * For this case, go ahead and clear the unnecssary bits
                 * to avoid any confusion with ->data_direction.
                 */
                hdr->flags &= ~ISCSI_FLAG_CMD_READ;
                hdr->flags &= ~ISCSI_FLAG_CMD_WRITE;

                pr_warn("ISCSI_FLAG_CMD_READ or ISCSI_FLAG_CMD_WRITE"
                        " set when Expected Data Transfer Length is 0 for"
                        " CDB: 0x%02x, Fixing up flags\n", hdr->cdb[0]);
        }

        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_cmd(cmd,
                                             ISCSI_REASON_BOOKMARK_INVALID, buf);
        }

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

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

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

        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_cmd(cmd,
                                             ISCSI_REASON_PROTOCOL_ERROR, buf);
        }

        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_cmd(cmd,
                                             ISCSI_REASON_PROTOCOL_ERROR, buf);
        }

        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_cmd(cmd,
                                             ISCSI_REASON_PROTOCOL_ERROR, buf);
        }

        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_cmd(cmd,
                                             ISCSI_REASON_BOOKMARK_INVALID, buf);
        }

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

        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 = TCM_SIMPLE_TAG;
        else if (iscsi_task_attr == ISCSI_ATTR_ORDERED)
                sam_task_attr = TCM_ORDERED_TAG;
        else if (iscsi_task_attr == ISCSI_ATTR_HEAD_OF_QUEUE)
                sam_task_attr = TCM_HEAD_TAG;
        else if (iscsi_task_attr == ISCSI_ATTR_ACA)
                sam_task_attr = TCM_ACA_TAG;
        else {
                pr_debug("Unknown iSCSI Task Attribute: 0x%02x, using"
                        " TCM_SIMPLE_TAG\n", iscsi_task_attr);
                sam_task_attr = TCM_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)
                cmd->targ_xfer_tag = session_get_next_ttt(conn->sess);
        else
                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 (!conn->sess->sess_ops->RDMAExtensions &&
             cmd->data_direction == DMA_FROM_DEVICE) {
                struct iscsi_datain_req *dr;

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

                iscsit_attach_datain_req(cmd, dr);
        }

        /*
         * Initialize struct se_cmd descriptor from target_core_mod infrastructure
         */
        transport_init_se_cmd(&cmd->se_cmd, &iscsi_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, be32_to_cpu(hdr->data_length), payload_length,
                conn->cid);

        target_get_sess_cmd(&cmd->se_cmd, true);

        cmd->sense_reason = transport_lookup_cmd_lun(&cmd->se_cmd,
                                                     scsilun_to_int(&hdr->lun));
        if (cmd->sense_reason)
                goto attach_cmd;

        /* only used for printks or comparing with ->ref_task_tag */
        cmd->se_cmd.tag = (__force u32)cmd->init_task_tag;
        cmd->sense_reason = target_setup_cmd_from_cdb(&cmd->se_cmd, hdr->cdb);
        if (cmd->sense_reason) {
                if (cmd->sense_reason == TCM_OUT_OF_RESOURCES) {
                        return iscsit_add_reject_cmd(cmd,
                                        ISCSI_REASON_BOOKMARK_NO_RESOURCES, buf);
                }

                goto attach_cmd;
        }

        if (iscsit_build_pdu_and_seq_lists(cmd, payload_length) < 0) {
                return iscsit_add_reject_cmd(cmd,
                                ISCSI_REASON_BOOKMARK_NO_RESOURCES, buf);
        }

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);

        return 0;
}
EXPORT_SYMBOL(iscsit_setup_scsi_cmd);

void iscsit_set_unsolicited_dataout(struct iscsi_cmd *cmd)
{
        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);
}
EXPORT_SYMBOL(iscsit_set_unsolicited_dataout);

int iscsit_process_scsi_cmd(struct iscsi_conn *conn, struct iscsi_cmd *cmd,
                            struct iscsi_scsi_req *hdr)
{
        int cmdsn_ret = 0;
        /*
         * 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,
                                        (unsigned char *)hdr, hdr->cmdsn);
                if (cmdsn_ret == CMDSN_ERROR_CANNOT_RECOVER)
                        return -1;
                else if (cmdsn_ret == CMDSN_LOWER_THAN_EXP) {
                        target_put_sess_cmd(&cmd->se_cmd);
                        return 0;
                }
        }

        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 (!cmd->sense_reason && cmd->unsolicited_data)
                        iscsit_set_unsolicited_dataout(cmd);
                if (!cmd->sense_reason)
                        return 0;

                target_put_sess_cmd(&cmd->se_cmd);
                return 0;
        }

        /*
         * Early CHECK_CONDITIONs with ImmediateData never make it to command
         * execution.  These exceptions are processed in CmdSN order using
         * iscsit_check_received_cmdsn() in iscsit_get_immediate_data() below.
         */
        if (cmd->sense_reason)
                return 1;
        /*
         * Call directly into transport_generic_new_cmd() to perform
         * the backend memory allocation.
         */
        cmd->sense_reason = transport_generic_new_cmd(&cmd->se_cmd);
        if (cmd->sense_reason)
                return 1;

        return 0;
}
EXPORT_SYMBOL(iscsit_process_scsi_cmd);

static int
iscsit_get_immediate_data(struct iscsi_cmd *cmd, struct iscsi_scsi_req *hdr,
                          bool dump_payload)
{
        int cmdsn_ret = 0, immed_ret = IMMEDIATE_DATA_NORMAL_OPERATION;
        int rc;

        /*
         * Special case for Unsupported SAM WRITE Opcodes and ImmediateData=Yes.
         */
        if (dump_payload) {
                u32 length = min(cmd->se_cmd.data_length - cmd->write_data_done,
                                 cmd->first_burst_len);

                pr_debug("Dumping min(%d - %d, %d) = %d bytes of immediate data\n",
                         cmd->se_cmd.data_length, cmd->write_data_done,
                         cmd->first_burst_len, length);
                rc = iscsit_dump_data_payload(cmd->conn, length, 1);
                pr_debug("Finished dumping immediate data\n");
                if (rc < 0)
                        immed_ret = IMMEDIATE_DATA_CANNOT_RECOVER;
        } else {
                immed_ret = iscsit_handle_immediate_data(cmd, hdr,
                                                         cmd->first_burst_len);
        }

        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(cmd->conn, cmd,
                                        (unsigned char *)hdr, hdr->cmdsn);
                if (cmdsn_ret == CMDSN_ERROR_CANNOT_RECOVER)
                        return -1;

                if (cmd->sense_reason || cmdsn_ret == CMDSN_LOWER_THAN_EXP) {
                        target_put_sess_cmd(&cmd->se_cmd);

                        return 0;
                } else if (cmd->unsolicited_data)
                        iscsit_set_unsolicited_dataout(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, cmd->conn, cmd->i_state);
        } else /* immed_ret == IMMEDIATE_DATA_CANNOT_RECOVER */
                return -1;

        return 0;
}

static int
iscsit_handle_scsi_cmd(struct iscsi_conn *conn, struct iscsi_cmd *cmd,
                           unsigned char *buf)
{
        struct iscsi_scsi_req *hdr = (struct iscsi_scsi_req *)buf;
        int rc, immed_data;
        bool dump_payload = false;

        rc = iscsit_setup_scsi_cmd(conn, cmd, buf);
        if (rc < 0)
                return 0;
        /*
         * Allocation iovecs needed for struct socket operations for
         * traditional iSCSI block I/O.
         */
        if (iscsit_allocate_iovecs(cmd) < 0) {
                return iscsit_reject_cmd(cmd,
                                ISCSI_REASON_BOOKMARK_NO_RESOURCES, buf);
        }
        immed_data = cmd->immediate_data;

        rc = iscsit_process_scsi_cmd(conn, cmd, hdr);
        if (rc < 0)
                return rc;
        else if (rc > 0)
                dump_payload = true;

        if (!immed_data)
                return 0;

        return iscsit_get_immediate_data(cmd, hdr, dump_payload);
}

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

        crypto_ahash_init(hash);

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

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

                ahash_request_set_crypt(hash, sg, NULL, cur_len);
                crypto_ahash_update(hash);

                data_length -= cur_len;
                page_off = 0;
                /* iscsit_map_iovec has already checked for invalid sg pointers */
                sg = sg_next(sg);
        }

        if (padding) {
                struct scatterlist pad_sg;

                sg_init_one(&pad_sg, pad_bytes, padding);
                ahash_request_set_crypt(hash, &pad_sg, (u8 *)&data_crc,
                                        padding);
                crypto_ahash_finup(hash);
        } else {
                ahash_request_set_crypt(hash, NULL, (u8 *)&data_crc, 0);
                crypto_ahash_final(hash);
        }

        return data_crc;
}

static void iscsit_do_crypto_hash_buf(struct ahash_request *hash,
        const void *buf, u32 payload_length, u32 padding,
        const void *pad_bytes, void *data_crc)
{
        struct scatterlist sg[2];

        sg_init_table(sg, ARRAY_SIZE(sg));
        sg_set_buf(sg, buf, payload_length);
        if (padding)
                sg_set_buf(sg + 1, pad_bytes, padding);

        ahash_request_set_crypt(hash, sg, data_crc, payload_length + padding);

        crypto_ahash_digest(hash);
}

int
__iscsit_check_dataout_hdr(struct iscsi_conn *conn, void *buf,
                           struct iscsi_cmd *cmd, u32 payload_length,
                           bool *success)
{
        struct iscsi_data *hdr = buf;
        struct se_cmd *se_cmd;
        int rc;

        /* iSCSI write */
        atomic_long_add(payload_length, &conn->sess->rx_data_octets);

        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, ntohl(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_dump_data_payload(conn, payload_length, 1);
        }
        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",
                       be32_to_cpu(hdr->offset), payload_length,
                       cmd->se_cmd.data_length);
                return iscsit_reject_cmd(cmd, ISCSI_REASON_BOOKMARK_INVALID, buf);
        }

        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... */
                WARN_ON(se_cmd->t_state != TRANSPORT_WRITE_PENDING);
                if (!(se_cmd->se_cmd_flags & SCF_SUPPORTED_SAM_OPCODE))
                        dump_unsolicited_data = 1;

                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 unsolicited data out.
                         */
                        if (hdr->flags & ISCSI_FLAG_CMD_FINAL)
                                iscsit_stop_dataout_timer(cmd);

                        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 &&
                            --cmd->outstanding_r2ts < 1)
                                iscsit_stop_dataout_timer(cmd);

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

int
iscsit_check_dataout_hdr(struct iscsi_conn *conn, void *buf,
                         struct iscsi_cmd **out_cmd)
{
        struct iscsi_data *hdr = buf;
        struct iscsi_cmd *cmd;
        u32 payload_length = ntoh24(hdr->dlength);
        int rc;
        bool success = false;

        if (!payload_length) {
                pr_warn_ratelimited("DataOUT payload is ZERO, ignoring.\n");
                return 0;
        }

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

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

        rc = __iscsit_check_dataout_hdr(conn, buf, cmd, payload_length, &success);

        if (success)
                *out_cmd = cmd;

        return rc;
}
EXPORT_SYMBOL(iscsit_check_dataout_hdr);

static int
iscsit_get_dataout(struct iscsi_conn *conn, struct iscsi_cmd *cmd,
                   struct iscsi_data *hdr)
{
        struct kvec *iov;
        u32 checksum, iov_count = 0, padding = 0, rx_got = 0, rx_size = 0;
        u32 payload_length;
        int iov_ret, data_crc_failed = 0;

        payload_length = min_t(u32, cmd->se_cmd.data_length,
                               ntoh24(hdr->dlength));
        rx_size += payload_length;
        iov = &cmd->iov_data[0];

        iov_ret = iscsit_map_iovec(cmd, iov, cmd->orig_iov_data_count - 2,
                                   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;
        }

        WARN_ON_ONCE(iov_count > cmd->orig_iov_data_count);
        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);
                }
        }

        return data_crc_failed;
}

int
iscsit_check_dataout_payload(struct iscsi_cmd *cmd, struct iscsi_data *hdr,
                             bool data_crc_failed)
{
        struct iscsi_conn *conn = cmd->conn;
        int rc, ooo_cmdsn;
        /*
         * Increment post receive data and CRC values or perform
         * within-command recovery.
         */
        rc = iscsit_check_post_dataout(cmd, (unsigned char *)hdr, data_crc_failed);
        if ((rc == DATAOUT_NORMAL) || (rc == DATAOUT_WITHIN_COMMAND_RECOVERY))
                return 0;
        else if (rc == DATAOUT_SEND_R2T) {
                iscsit_set_dataout_sequence_values(cmd);
                conn->conn_transport->iscsit_get_dataout(conn, cmd, false);
        } else if (rc == 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;
}
EXPORT_SYMBOL(iscsit_check_dataout_payload);

static int iscsit_handle_data_out(struct iscsi_conn *conn, unsigned char *buf)
{
        struct iscsi_cmd *cmd = NULL;
        struct iscsi_data *hdr = (struct iscsi_data *)buf;
        int rc;
        bool data_crc_failed = false;

        rc = iscsit_check_dataout_hdr(conn, buf, &cmd);
        if (rc < 0)
                return 0;
        else if (!cmd)
                return 0;

        rc = iscsit_get_dataout(conn, cmd, hdr);
        if (rc < 0)
                return rc;
        else if (rc > 0)
                data_crc_failed = true;

        return iscsit_check_dataout_payload(cmd, hdr, data_crc_failed);
}

int iscsit_setup_nop_out(struct iscsi_conn *conn, struct iscsi_cmd *cmd,
                         struct iscsi_nopout *hdr)
{
        u32 payload_length = ntoh24(hdr->dlength);

        if (!(hdr->flags & ISCSI_FLAG_CMD_FINAL)) {
                pr_err("NopOUT Flag's, Left Most Bit not set, protocol error.\n");
                if (!cmd)
                        return iscsit_add_reject(conn, ISCSI_REASON_PROTOCOL_ERROR,
                                                 (unsigned char *)hdr);
                
                return iscsit_reject_cmd(cmd, ISCSI_REASON_PROTOCOL_ERROR,
                                         (unsigned char *)hdr);
        }

        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");
                if (!cmd)
                        return iscsit_add_reject(conn, ISCSI_REASON_PROTOCOL_ERROR,
                                                 (unsigned char *)hdr);

                return iscsit_reject_cmd(cmd, ISCSI_REASON_PROTOCOL_ERROR,
                                         (unsigned char *)hdr);
        }

        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);
                if (!cmd)
                        return iscsit_add_reject(conn, ISCSI_REASON_PROTOCOL_ERROR,
                                                 (unsigned char *)hdr);

                return iscsit_reject_cmd(cmd, ISCSI_REASON_PROTOCOL_ERROR,
                                         (unsigned char *)hdr);
        }

        pr_debug("Got NOPOUT Ping %s ITT: 0x%08x, TTT: 0x%08x,"
                " 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->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;
        }

        return 0;
}
EXPORT_SYMBOL(iscsit_setup_nop_out);

int iscsit_process_nop_out(struct iscsi_conn *conn, struct iscsi_cmd *cmd,
                           struct iscsi_nopout *hdr)
{
        struct iscsi_cmd *cmd_p = NULL;
        int cmdsn_ret = 0;
        /*
         * Initiator is expecting a NopIN ping reply..
         */
        if (hdr->itt != RESERVED_ITT) {
                if (!cmd)
                        return iscsit_add_reject(conn, ISCSI_REASON_PROTOCOL_ERROR,
                                                (unsigned char *)hdr);

                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,
                                (unsigned char *)hdr, hdr->cmdsn);
                if (cmdsn_ret == CMDSN_LOWER_THAN_EXP)
                        return 0;
                if (cmdsn_ret == CMDSN_ERROR_CANNOT_RECOVER)
                        return -1;

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

                iscsit_stop_nopin_response_timer(conn);

                cmd_p->i_state = ISTATE_REMOVE;
                iscsit_add_cmd_to_immediate_queue(cmd_p, conn, cmd_p->i_state);

                iscsit_start_nopin_timer(conn);
                return 0;
        }
        /*
         * Otherwise, initiator is not expecting a NOPIN is response.
         * Just ignore for now.
         */

        if (cmd)
                iscsit_free_cmd(cmd, false);

        return 0;
}
EXPORT_SYMBOL(iscsit_process_nop_out);

static int iscsit_handle_nop_out(struct iscsi_conn *conn, struct iscsi_cmd *cmd,
                                 unsigned char *buf)
{
        unsigned char *ping_data = NULL;
        struct iscsi_nopout *hdr = (struct iscsi_nopout *)buf;
        struct kvec *iov = NULL;
        u32 payload_length = ntoh24(hdr->dlength);
        int ret;

        ret = iscsit_setup_nop_out(conn, cmd, hdr);
        if (ret < 0)
                return 0;
        /*
         * Handle NOP-OUT payload for traditional iSCSI sockets
         */
        if (payload_length && hdr->ttt == cpu_to_be32(0xFFFFFFFF)) {
                u32 checksum, data_crc, padding = 0;
                int niov = 0, rx_got, rx_size = payload_length;

                ping_data = kzalloc(payload_length + 1, GFP_KERNEL);
                if (!ping_data) {
                        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;
                }

                WARN_ON_ONCE(niov > ARRAY_SIZE(cmd->iov_misc));
                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, &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);
        }

        return iscsit_process_nop_out(conn, cmd, hdr);
out:
        if (cmd)
                iscsit_free_cmd(cmd, false);

        kfree(ping_data);
        return ret;
}

static enum tcm_tmreq_table iscsit_convert_tmf(u8 iscsi_tmf)
{
        switch (iscsi_tmf) {
        case ISCSI_TM_FUNC_ABORT_TASK:
                return TMR_ABORT_TASK;
        case ISCSI_TM_FUNC_ABORT_TASK_SET:
                return TMR_ABORT_TASK_SET;
        case ISCSI_TM_FUNC_CLEAR_ACA:
                return TMR_CLEAR_ACA;
        case ISCSI_TM_FUNC_CLEAR_TASK_SET:
                return TMR_CLEAR_TASK_SET;
        case ISCSI_TM_FUNC_LOGICAL_UNIT_RESET:
                return TMR_LUN_RESET;
        case ISCSI_TM_FUNC_TARGET_WARM_RESET:
                return TMR_TARGET_WARM_RESET;
        case ISCSI_TM_FUNC_TARGET_COLD_RESET:
                return TMR_TARGET_COLD_RESET;
        default:
                return TMR_UNKNOWN;
        }
}

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

        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_cmd(cmd,
                                             ISCSI_REASON_PROTOCOL_ERROR, buf);
        }
        if ((function != ISCSI_TM_FUNC_ABORT_TASK) &&
            be32_to_cpu(hdr->refcmdsn) != ISCSI_RESERVED_TAG)
                hdr->refcmdsn = cpu_to_be32(ISCSI_RESERVED_TAG);

        cmd->data_direction = DMA_NONE;
        cmd->tmr_req = kzalloc(sizeof(*cmd->tmr_req), GFP_KERNEL);
        if (!cmd->tmr_req) {
                return iscsit_add_reject_cmd(cmd,
                                             ISCSI_REASON_BOOKMARK_NO_RESOURCES,
                                             buf);
        }

        transport_init_se_cmd(&cmd->se_cmd, &iscsi_ops,
                              conn->sess->se_sess, 0, DMA_NONE,
                              TCM_SIMPLE_TAG, cmd->sense_buffer + 2);

        target_get_sess_cmd(&cmd->se_cmd, true);

        /*
         * TASK_REASSIGN for ERL=2 / connection stays inside of
         * LIO-Target $FABRIC_MOD
         */
        if (function != ISCSI_TM_FUNC_TASK_REASSIGN) {
                tcm_function = iscsit_convert_tmf(function);
                if (tcm_function == TMR_UNKNOWN) {
                        pr_err("Unknown iSCSI TMR Function:"
                               " 0x%02x\n", function);
                        return iscsit_add_reject_cmd(cmd,
                                ISCSI_REASON_BOOKMARK_NO_RESOURCES, buf);
                }
        }
        ret = core_tmr_alloc_req(&cmd->se_cmd, cmd->tmr_req, tcm_function,
                                 GFP_KERNEL);
        if (ret < 0)
                return iscsit_add_reject_cmd(cmd,
                                ISCSI_REASON_BOOKMARK_NO_RESOURCES, buf);

        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) {
                        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)
                        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) {
                        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) {
                        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)
                        break;

                if (iscsit_check_task_reassign_expdatasn(tmr_req, conn) < 0)
                        return iscsit_add_reject_cmd(cmd,
                                        ISCSI_REASON_BOOKMARK_INVALID, buf);
                break;
        default:
                pr_err("Unknown TMR function: 0x%02x, protocol"
                        " error.\n", function);
                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, buf, hdr->cmdsn);
                if (cmdsn_ret == CMDSN_HIGHER_THAN_EXP) {
                        out_of_order_cmdsn = 1;
                } else if (cmdsn_ret == CMDSN_LOWER_THAN_EXP) {
                        target_put_sess_cmd(&cmd->se_cmd);
                        return 0;
                } else if (cmdsn_ret == CMDSN_ERROR_CANNOT_RECOVER) {
                        return -1;
                }
        }
        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);
        target_put_sess_cmd(&cmd->se_cmd);
        return 0;
}
EXPORT_SYMBOL(iscsit_handle_task_mgt_cmd);

/* #warning FIXME: Support Text Command parameters besides SendTargets */
int
iscsit_setup_text_cmd(struct iscsi_conn *conn, struct iscsi_cmd *cmd,
                      struct iscsi_text *hdr)
{
        u32 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_reject_cmd(cmd, ISCSI_REASON_PROTOCOL_ERROR,
                                         (unsigned char *)hdr);
        }

        if (!(hdr->flags & ISCSI_FLAG_CMD_FINAL) ||
             (hdr->flags & ISCSI_FLAG_TEXT_CONTINUE)) {
                pr_err("Multi sequence text commands currently not supported\n");
                return iscsit_reject_cmd(cmd, ISCSI_REASON_CMD_NOT_SUPPORTED,
                                        (unsigned char *)hdr);
        }

        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);

        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;
        kfree(cmd->text_in_ptr);
        cmd->text_in_ptr        = NULL;

        return 0;
}
EXPORT_SYMBOL(iscsit_setup_text_cmd);

int
iscsit_process_text_cmd(struct iscsi_conn *conn, struct iscsi_cmd *cmd,
                        struct iscsi_text *hdr)
{
        unsigned char *text_in = cmd->text_in_ptr, *text_ptr;
        int cmdsn_ret;

        if (!text_in) {
                cmd->targ_xfer_tag = be32_to_cpu(hdr->ttt);
                if (cmd->targ_xfer_tag == 0xFFFFFFFF) {
                        pr_err("Unable to locate text_in buffer for sendtargets"
                               " discovery\n");
                        goto reject;
                }
                goto empty_sendtargets;
        }
        if (strncmp("SendTargets", text_in, 11) != 0) {
                pr_err("Received Text Data that is not"
                        " SendTargets, cannot continue.\n");
                goto reject;
        }
        text_ptr = strchr(text_in, '=');
        if (!text_ptr) {
                pr_err("No \"=\" separator found in Text Data,"
                        "  cannot continue.\n");
                goto reject;
        }
        if (!strncmp("=All", text_ptr, 4)) {
                cmd->cmd_flags |= ICF_SENDTARGETS_ALL;
        } else if (!strncmp("=iqn.", text_ptr, 5) ||
                   !strncmp("=eui.", text_ptr, 5)) {
                cmd->cmd_flags |= ICF_SENDTARGETS_SINGLE;
        } else {
                pr_err("Unable to locate valid SendTargets=%s value\n", text_ptr);
                goto reject;
        }

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

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

        if (!(hdr->opcode & ISCSI_OP_IMMEDIATE)) {
                cmdsn_ret = iscsit_sequence_cmd(conn, cmd,
                                (unsigned char *)hdr, hdr->cmdsn);
                if (cmdsn_ret == CMDSN_ERROR_CANNOT_RECOVER)
                        return -1;

                return 0;
        }

        return iscsit_execute_cmd(cmd, 0);

reject:
        return iscsit_reject_cmd(cmd, ISCSI_REASON_PROTOCOL_ERROR,
                                 (unsigned char *)hdr);
}
EXPORT_SYMBOL(iscsit_process_text_cmd);

static int
iscsit_handle_text_cmd(struct iscsi_conn *conn, struct iscsi_cmd *cmd,
                       unsigned char *buf)
{
        struct iscsi_text *hdr = (struct iscsi_text *)buf;
        char *text_in = NULL;
        u32 payload_length = ntoh24(hdr->dlength);
        int rx_size, rc;

        rc = iscsit_setup_text_cmd(conn, cmd, hdr);
        if (rc < 0)
                return 0;

        rx_size = payload_length;
        if (payload_length) {
                u32 checksum = 0, data_crc = 0;
                u32 padding = 0;
                int niov = 0, rx_got;
                struct kvec iov[2];

                rx_size = ALIGN(payload_length, 4);
                text_in = kzalloc(rx_size, GFP_KERNEL);
                if (!text_in)
                        goto reject;

                cmd->text_in_ptr = text_in;

                memset(iov, 0, sizeof(iov));
                iov[niov].iov_base      = text_in;
                iov[niov++].iov_len     = rx_size;

                padding = rx_size - payload_length;
                if (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;
                }

                WARN_ON_ONCE(niov > ARRAY_SIZE(iov));
                rx_got = rx_data(conn, &iov[0], niov, rx_size);
                if (rx_got != rx_size)
                        goto reject;

                if (conn->conn_ops->DataDigest) {
                        iscsit_do_crypto_hash_buf(conn->conn_rx_hash,
                                                  text_in, rx_size, 0, NULL,
                                                  &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");
                                        goto reject;
                                } 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, payload_length);
                        }
                }
                text_in[payload_length - 1] = '\0';
                pr_debug("Successfully read %d bytes of text"
                                " data.\n", payload_length);
        }

        return iscsit_process_text_cmd(conn, cmd, hdr);

reject:
        kfree(cmd->text_in_ptr);
        cmd->text_in_ptr = NULL;
        return iscsit_reject_cmd(cmd, ISCSI_REASON_PROTOCOL_ERROR, buf);
}

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;
}

int
iscsit_handle_logout_cmd(struct iscsi_conn *conn, struct iscsi_cmd *cmd,
                        unsigned char *buf)
{
        int cmdsn_ret, logout_remove = 0;
        u8 reason_code = 0;
        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");
                iscsit_free_cmd(cmd, false);
                return 0;
        }

        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, buf, hdr->cmdsn);
                if (cmdsn_ret == CMDSN_LOWER_THAN_EXP)
                        logout_remove = 0;
                else if (cmdsn_ret == CMDSN_ERROR_CANNOT_RECOVER)
                        return -1;
        }

        return logout_remove;
}
EXPORT_SYMBOL(iscsit_handle_logout_cmd);

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(conn, ISCSI_REASON_PROTOCOL_ERROR,
                                         buf);
        }
        /*
         * 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(conn, ISCSI_REASON_PROTOCOL_ERROR,
                                         buf);
        default:
                pr_err("Unknown SNACK type 0x%02x, protocol"
                        " error.\n", hdr->flags & 0x0f);
                return iscsit_add_reject(conn, ISCSI_REASON_PROTOCOL_ERROR,
                                         buf);
        }

        return 0;
}
EXPORT_SYMBOL(iscsit_handle_snack);

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,
        struct iscsi_scsi_req *hdr,
        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;
        void *overflow_buf = NULL;

        BUG_ON(cmd->write_data_done > cmd->se_cmd.data_length);
        rx_size = min(cmd->se_cmd.data_length - cmd->write_data_done, length);
        iov_ret = iscsit_map_iovec(cmd, cmd->iov_data,
                                   cmd->orig_iov_data_count - 2,
                                   cmd->write_data_done, rx_size);
        if (iov_ret < 0)
                return IMMEDIATE_DATA_CANNOT_RECOVER;

        iov_count = iov_ret;
        iov = &cmd->iov_data[0];
        if (rx_size < length) {
                /*
                 * Special case: length of immediate data exceeds the data
                 * buffer size derived from the CDB.
                 */
                overflow_buf = kmalloc(length - rx_size, GFP_KERNEL);
                if (!overflow_buf) {
                        iscsit_unmap_iovec(cmd);
                        return IMMEDIATE_DATA_CANNOT_RECOVER;
                }
                cmd->overflow_buf = overflow_buf;
                iov[iov_count].iov_base = overflow_buf;
                iov[iov_count].iov_len = length - rx_size;
                iov_count++;
                rx_size = length;
        }

        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;
        }

        WARN_ON_ONCE(iov_count > cmd->orig_iov_data_count);
        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_reject_cmd(cmd,
                                                ISCSI_REASON_DATA_DIGEST_ERROR,
                                                (unsigned char *)hdr);
                                return IMMEDIATE_DATA_CANNOT_RECOVER;
                        } else {
                                iscsit_reject_cmd(cmd,
                                                ISCSI_REASON_DATA_DIGEST_ERROR,
                                                (unsigned char *)hdr);
                                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;
}

/* #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;
        bool found = false;

        lockdep_assert_held(&conn->sess->conn_lock);

        /*
         * 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);
                        found = true;
                        break;
                }
        }

        if (!found)
                return;

        cmd = iscsit_allocate_cmd(conn_p, TASK_RUNNING);
        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->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((u32) atomic_read(&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);

        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 conn->conn_transport->iscsit_xmit_pdu(conn, cmd, NULL, NULL, 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);
        }
}

void
iscsit_build_datain_pdu(struct iscsi_cmd *cmd, struct iscsi_conn *conn,
                        struct iscsi_datain *datain, struct iscsi_data_rsp *hdr,
                        bool set_statsn)
{
        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((u32) atomic_read(&conn->sess->max_cmd_sn));
        hdr->datasn             = cpu_to_be32(datain->data_sn);
        hdr->offset             = cpu_to_be32(datain->offset);

        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);
}
EXPORT_SYMBOL(iscsit_build_datain_pdu);

static int iscsit_send_datain(struct iscsi_cmd *cmd, struct iscsi_conn *conn)
{
        struct iscsi_data_rsp *hdr = (struct iscsi_data_rsp *)&cmd->pdu[0];
        struct iscsi_datain datain;
        struct iscsi_datain_req *dr;
        int eodr = 0, ret;
        bool set_statsn = false;

        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;
        }

        atomic_long_add(datain.length, &conn->sess->tx_data_octets);
        /*
         * 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 = true;
                } else if (dr->dr_complete ==
                           DATAIN_COMPLETE_WITHIN_COMMAND_RECOVERY)
                        set_statsn = true;
        }

        iscsit_build_datain_pdu(cmd, conn, &datain, hdr, set_statsn);

        ret = conn->conn_transport->iscsit_xmit_pdu(conn, cmd, dr, &datain, 0);
        if (ret < 0)
                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;
}

int
iscsit_build_logout_rsp(struct iscsi_cmd *cmd, struct iscsi_conn *conn,
                        struct iscsi_logout_rsp *hdr)
{
        struct iscsi_conn *logout_conn = NULL;
        struct iscsi_conn_recovery *cr = NULL;
        struct iscsi_session *sess = conn->sess;
        /*
         * 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;
        }

        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((u32) atomic_read(&conn->sess->max_cmd_sn));

        pr_debug("Built 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;
}
EXPORT_SYMBOL(iscsit_build_logout_rsp);

static int
iscsit_send_logout(struct iscsi_cmd *cmd, struct iscsi_conn *conn)
{
        int rc;

        rc = iscsit_build_logout_rsp(cmd, conn,
                        (struct iscsi_logout_rsp *)&cmd->pdu[0]);
        if (rc < 0)
                return rc;

        return conn->conn_transport->iscsit_xmit_pdu(conn, cmd, NULL, NULL, 0);
}

void
iscsit_build_nopin_rsp(struct iscsi_cmd *cmd, struct iscsi_conn *conn,
                       struct iscsi_nopin *hdr, bool nopout_response)
{
        hdr->opcode             = ISCSI_OP_NOOP_IN;
        hdr->flags              |= ISCSI_FLAG_CMD_FINAL;
        hton24(hdr->dlength, cmd->buf_ptr_size);
        if (nopout_response)
                put_unaligned_le64(0xFFFFFFFFFFFFFFFFULL, &hdr->lun);
        hdr->itt                = cmd->init_task_tag;
        hdr->ttt                = cpu_to_be32(cmd->targ_xfer_tag);
        cmd->stat_sn            = (nopout_response) ? conn->stat_sn++ :
                                  conn->stat_sn;
        hdr->statsn             = cpu_to_be32(cmd->stat_sn);

        if (nopout_response)
                iscsit_increment_maxcmdsn(cmd, conn->sess);