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libiscsi.c

/*
 * iSCSI lib functions
 *
 * Copyright (C) 2006 Red Hat, Inc.  All rights reserved.
 * Copyright (C) 2004 - 2006 Mike Christie
 * Copyright (C) 2004 - 2005 Dmitry Yusupov
 * Copyright (C) 2004 - 2005 Alex Aizman
 * maintained by open-iscsi@googlegroups.com
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation; either version 2 of the License, or
 * (at your option) any later version.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program; if not, write to the Free Software
 * Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
 */
#include <linux/types.h>
#include <linux/kfifo.h>
#include <linux/delay.h>
#include <linux/log2.h>
#include <asm/unaligned.h>
#include <net/tcp.h>
#include <scsi/scsi_cmnd.h>
#include <scsi/scsi_device.h>
#include <scsi/scsi_eh.h>
#include <scsi/scsi_tcq.h>
#include <scsi/scsi_host.h>
#include <scsi/scsi.h>
#include <scsi/iscsi_proto.h>
#include <scsi/scsi_transport.h>
#include <scsi/scsi_transport_iscsi.h>
#include <scsi/libiscsi.h>

static int iscsi_dbg_lib_conn;
module_param_named(debug_libiscsi_conn, iscsi_dbg_lib_conn, int,
               S_IRUGO | S_IWUSR);
MODULE_PARM_DESC(debug_libiscsi_conn,
             "Turn on debugging for connections in libiscsi module. "
             "Set to 1 to turn on, and zero to turn off. Default is off.");

static int iscsi_dbg_lib_session;
module_param_named(debug_libiscsi_session, iscsi_dbg_lib_session, int,
               S_IRUGO | S_IWUSR);
MODULE_PARM_DESC(debug_libiscsi_session,
             "Turn on debugging for sessions in libiscsi module. "
             "Set to 1 to turn on, and zero to turn off. Default is off.");

static int iscsi_dbg_lib_eh;
module_param_named(debug_libiscsi_eh, iscsi_dbg_lib_eh, int,
               S_IRUGO | S_IWUSR);
MODULE_PARM_DESC(debug_libiscsi_eh,
             "Turn on debugging for error handling in libiscsi module. "
             "Set to 1 to turn on, and zero to turn off. Default is off.");

#define ISCSI_DBG_CONN(_conn, dbg_fmt, arg...)              \
      do {                                      \
            if (iscsi_dbg_lib_conn)                   \
                  iscsi_conn_printk(KERN_INFO, _conn, \
                                   "%s " dbg_fmt,     \
                                   __func__, ##arg);  \
      } while (0);

#define ISCSI_DBG_SESSION(_session, dbg_fmt, arg...)              \
      do {                                            \
            if (iscsi_dbg_lib_session)                      \
                  iscsi_session_printk(KERN_INFO, _session, \
                                   "%s " dbg_fmt,           \
                                   __func__, ##arg);        \
      } while (0);

#define ISCSI_DBG_EH(_session, dbg_fmt, arg...)                   \
      do {                                            \
            if (iscsi_dbg_lib_eh)                           \
                  iscsi_session_printk(KERN_INFO, _session, \
                                   "%s " dbg_fmt,           \
                                   __func__, ##arg);        \
      } while (0);

/* Serial Number Arithmetic, 32 bits, less than, RFC1982 */
#define SNA32_CHECK 2147483648UL

static int iscsi_sna_lt(u32 n1, u32 n2)
{
      return n1 != n2 && ((n1 < n2 && (n2 - n1 < SNA32_CHECK)) ||
                      (n1 > n2 && (n2 - n1 < SNA32_CHECK)));
}

/* Serial Number Arithmetic, 32 bits, less than, RFC1982 */
static int iscsi_sna_lte(u32 n1, u32 n2)
{
      return n1 == n2 || ((n1 < n2 && (n2 - n1 < SNA32_CHECK)) ||
                      (n1 > n2 && (n2 - n1 < SNA32_CHECK)));
}

inline void iscsi_conn_queue_work(struct iscsi_conn *conn)
{
      struct Scsi_Host *shost = conn->session->host;
      struct iscsi_host *ihost = shost_priv(shost);

      if (ihost->workq)
            queue_work(ihost->workq, &conn->xmitwork);
}
EXPORT_SYMBOL_GPL(iscsi_conn_queue_work);

void
iscsi_update_cmdsn(struct iscsi_session *session, struct iscsi_nopin *hdr)
{
      uint32_t max_cmdsn = be32_to_cpu(hdr->max_cmdsn);
      uint32_t exp_cmdsn = be32_to_cpu(hdr->exp_cmdsn);

      /*
       * standard specifies this check for when to update expected and
       * max sequence numbers
       */
      if (iscsi_sna_lt(max_cmdsn, exp_cmdsn - 1))
            return;

      if (exp_cmdsn != session->exp_cmdsn &&
          !iscsi_sna_lt(exp_cmdsn, session->exp_cmdsn))
            session->exp_cmdsn = exp_cmdsn;

      if (max_cmdsn != session->max_cmdsn &&
          !iscsi_sna_lt(max_cmdsn, session->max_cmdsn)) {
            session->max_cmdsn = max_cmdsn;
            /*
             * if the window closed with IO queued, then kick the
             * xmit thread
             */
            if (!list_empty(&session->leadconn->cmdqueue) ||
                !list_empty(&session->leadconn->mgmtqueue))
                  iscsi_conn_queue_work(session->leadconn);
      }
}
EXPORT_SYMBOL_GPL(iscsi_update_cmdsn);

/**
 * iscsi_prep_data_out_pdu - initialize Data-Out
 * @task: scsi command task
 * @r2t: R2T info
 * @hdr: iscsi data in pdu
 *
 * Notes:
 *    Initialize Data-Out within this R2T sequence and finds
 *    proper data_offset within this SCSI command.
 *
 *    This function is called with connection lock taken.
 **/
void iscsi_prep_data_out_pdu(struct iscsi_task *task, struct iscsi_r2t_info *r2t,
                     struct iscsi_data *hdr)
{
      struct iscsi_conn *conn = task->conn;
      unsigned int left = r2t->data_length - r2t->sent;

      task->hdr_len = sizeof(struct iscsi_data);

      memset(hdr, 0, sizeof(struct iscsi_data));
      hdr->ttt = r2t->ttt;
      hdr->datasn = cpu_to_be32(r2t->datasn);
      r2t->datasn++;
      hdr->opcode = ISCSI_OP_SCSI_DATA_OUT;
      memcpy(hdr->lun, task->lun, sizeof(hdr->lun));
      hdr->itt = task->hdr_itt;
      hdr->exp_statsn = r2t->exp_statsn;
      hdr->offset = cpu_to_be32(r2t->data_offset + r2t->sent);
      if (left > conn->max_xmit_dlength) {
            hton24(hdr->dlength, conn->max_xmit_dlength);
            r2t->data_count = conn->max_xmit_dlength;
            hdr->flags = 0;
      } else {
            hton24(hdr->dlength, left);
            r2t->data_count = left;
            hdr->flags = ISCSI_FLAG_CMD_FINAL;
      }
      conn->dataout_pdus_cnt++;
}
EXPORT_SYMBOL_GPL(iscsi_prep_data_out_pdu);

static int iscsi_add_hdr(struct iscsi_task *task, unsigned len)
{
      unsigned exp_len = task->hdr_len + len;

      if (exp_len > task->hdr_max) {
            WARN_ON(1);
            return -EINVAL;
      }

      WARN_ON(len & (ISCSI_PAD_LEN - 1)); /* caller must pad the AHS */
      task->hdr_len = exp_len;
      return 0;
}

/*
 * make an extended cdb AHS
 */
static int iscsi_prep_ecdb_ahs(struct iscsi_task *task)
{
      struct scsi_cmnd *cmd = task->sc;
      unsigned rlen, pad_len;
      unsigned short ahslength;
      struct iscsi_ecdb_ahdr *ecdb_ahdr;
      int rc;

      ecdb_ahdr = iscsi_next_hdr(task);
      rlen = cmd->cmd_len - ISCSI_CDB_SIZE;

      BUG_ON(rlen > sizeof(ecdb_ahdr->ecdb));
      ahslength = rlen + sizeof(ecdb_ahdr->reserved);

      pad_len = iscsi_padding(rlen);

      rc = iscsi_add_hdr(task, sizeof(ecdb_ahdr->ahslength) +
                         sizeof(ecdb_ahdr->ahstype) + ahslength + pad_len);
      if (rc)
            return rc;

      if (pad_len)
            memset(&ecdb_ahdr->ecdb[rlen], 0, pad_len);

      ecdb_ahdr->ahslength = cpu_to_be16(ahslength);
      ecdb_ahdr->ahstype = ISCSI_AHSTYPE_CDB;
      ecdb_ahdr->reserved = 0;
      memcpy(ecdb_ahdr->ecdb, cmd->cmnd + ISCSI_CDB_SIZE, rlen);

      ISCSI_DBG_SESSION(task->conn->session,
                    "iscsi_prep_ecdb_ahs: varlen_cdb_len %d "
                      "rlen %d pad_len %d ahs_length %d iscsi_headers_size "
                      "%u\n", cmd->cmd_len, rlen, pad_len, ahslength,
                      task->hdr_len);
      return 0;
}

static int iscsi_prep_bidi_ahs(struct iscsi_task *task)
{
      struct scsi_cmnd *sc = task->sc;
      struct iscsi_rlength_ahdr *rlen_ahdr;
      int rc;

      rlen_ahdr = iscsi_next_hdr(task);
      rc = iscsi_add_hdr(task, sizeof(*rlen_ahdr));
      if (rc)
            return rc;

      rlen_ahdr->ahslength =
            cpu_to_be16(sizeof(rlen_ahdr->read_length) +
                                      sizeof(rlen_ahdr->reserved));
      rlen_ahdr->ahstype = ISCSI_AHSTYPE_RLENGTH;
      rlen_ahdr->reserved = 0;
      rlen_ahdr->read_length = cpu_to_be32(scsi_in(sc)->length);

      ISCSI_DBG_SESSION(task->conn->session,
                    "bidi-in rlen_ahdr->read_length(%d) "
                      "rlen_ahdr->ahslength(%d)\n",
                      be32_to_cpu(rlen_ahdr->read_length),
                      be16_to_cpu(rlen_ahdr->ahslength));
      return 0;
}

/**
 * iscsi_prep_scsi_cmd_pdu - prep iscsi scsi cmd pdu
 * @task: iscsi task
 *
 * Prep basic iSCSI PDU fields for a scsi cmd pdu. The LLD should set
 * fields like dlength or final based on how much data it sends
 */
static int iscsi_prep_scsi_cmd_pdu(struct iscsi_task *task)
{
      struct iscsi_conn *conn = task->conn;
      struct iscsi_session *session = conn->session;
      struct scsi_cmnd *sc = task->sc;
      struct iscsi_cmd *hdr;
      unsigned hdrlength, cmd_len;
      itt_t itt;
      int rc;

      if (conn->session->tt->alloc_pdu) {
            rc = conn->session->tt->alloc_pdu(task, ISCSI_OP_SCSI_CMD);
            if (rc)
                  return rc;
      }
      hdr = (struct iscsi_cmd *) task->hdr;
      itt = hdr->itt;
      memset(hdr, 0, sizeof(*hdr));

      if (session->tt->parse_pdu_itt)
            hdr->itt = task->hdr_itt = itt;
      else
            hdr->itt = task->hdr_itt = build_itt(task->itt,
                                         task->conn->session->age);
      task->hdr_len = 0;
      rc = iscsi_add_hdr(task, sizeof(*hdr));
      if (rc)
            return rc;
      hdr->opcode = ISCSI_OP_SCSI_CMD;
      hdr->flags = ISCSI_ATTR_SIMPLE;
      int_to_scsilun(sc->device->lun, (struct scsi_lun *)hdr->lun);
      memcpy(task->lun, hdr->lun, sizeof(task->lun));
      hdr->cmdsn = task->cmdsn = cpu_to_be32(session->cmdsn);
      session->cmdsn++;
      hdr->exp_statsn = cpu_to_be32(conn->exp_statsn);
      cmd_len = sc->cmd_len;
      if (cmd_len < ISCSI_CDB_SIZE)
            memset(&hdr->cdb[cmd_len], 0, ISCSI_CDB_SIZE - cmd_len);
      else if (cmd_len > ISCSI_CDB_SIZE) {
            rc = iscsi_prep_ecdb_ahs(task);
            if (rc)
                  return rc;
            cmd_len = ISCSI_CDB_SIZE;
      }
      memcpy(hdr->cdb, sc->cmnd, cmd_len);

      task->imm_count = 0;
      if (scsi_bidi_cmnd(sc)) {
            hdr->flags |= ISCSI_FLAG_CMD_READ;
            rc = iscsi_prep_bidi_ahs(task);
            if (rc)
                  return rc;
      }
      if (sc->sc_data_direction == DMA_TO_DEVICE) {
            unsigned out_len = scsi_out(sc)->length;
            struct iscsi_r2t_info *r2t = &task->unsol_r2t;

            hdr->data_length = cpu_to_be32(out_len);
            hdr->flags |= ISCSI_FLAG_CMD_WRITE;
            /*
             * Write counters:
             *
             *    imm_count   bytes to be sent right after
             *                SCSI PDU Header
             *
             *    unsol_count bytes(as Data-Out) to be sent
             *                without     R2T ack right after
             *                immediate data
             *
             *    r2t data_length bytes to be sent via R2T ack's
             *
             *      pad_count       bytes to be sent as zero-padding
             */
            memset(r2t, 0, sizeof(*r2t));

            if (session->imm_data_en) {
                  if (out_len >= session->first_burst)
                        task->imm_count = min(session->first_burst,
                                          conn->max_xmit_dlength);
                  else
                        task->imm_count = min(out_len,
                                          conn->max_xmit_dlength);
                  hton24(hdr->dlength, task->imm_count);
            } else
                  zero_data(hdr->dlength);

            if (!session->initial_r2t_en) {
                  r2t->data_length = min(session->first_burst, out_len) -
                                     task->imm_count;
                  r2t->data_offset = task->imm_count;
                  r2t->ttt = cpu_to_be32(ISCSI_RESERVED_TAG);
                  r2t->exp_statsn = cpu_to_be32(conn->exp_statsn);
            }

            if (!task->unsol_r2t.data_length)
                  /* No unsolicit Data-Out's */
                  hdr->flags |= ISCSI_FLAG_CMD_FINAL;
      } else {
            hdr->flags |= ISCSI_FLAG_CMD_FINAL;
            zero_data(hdr->dlength);
            hdr->data_length = cpu_to_be32(scsi_in(sc)->length);

            if (sc->sc_data_direction == DMA_FROM_DEVICE)
                  hdr->flags |= ISCSI_FLAG_CMD_READ;
      }

      /* calculate size of additional header segments (AHSs) */
      hdrlength = task->hdr_len - sizeof(*hdr);

      WARN_ON(hdrlength & (ISCSI_PAD_LEN-1));
      hdrlength /= ISCSI_PAD_LEN;

      WARN_ON(hdrlength >= 256);
      hdr->hlength = hdrlength & 0xFF;

      if (session->tt->init_task && session->tt->init_task(task))
            return -EIO;

      task->state = ISCSI_TASK_RUNNING;

      conn->scsicmd_pdus_cnt++;
      ISCSI_DBG_SESSION(session, "iscsi prep [%s cid %d sc %p cdb 0x%x "
                    "itt 0x%x len %d bidi_len %d cmdsn %d win %d]\n",
                    scsi_bidi_cmnd(sc) ? "bidirectional" :
                    sc->sc_data_direction == DMA_TO_DEVICE ?
                    "write" : "read", conn->id, sc, sc->cmnd[0],
                    task->itt, scsi_bufflen(sc),
                    scsi_bidi_cmnd(sc) ? scsi_in(sc)->length : 0,
                    session->cmdsn,
                    session->max_cmdsn - session->exp_cmdsn + 1);
      return 0;
}

/**
 * iscsi_free_task - free a task
 * @task: iscsi cmd task
 *
 * Must be called with session lock.
 * This function returns the scsi command to scsi-ml or cleans
 * up mgmt tasks then returns the task to the pool.
 */
static void iscsi_free_task(struct iscsi_task *task)
{
      struct iscsi_conn *conn = task->conn;
      struct iscsi_session *session = conn->session;
      struct scsi_cmnd *sc = task->sc;

      ISCSI_DBG_SESSION(session, "freeing task itt 0x%x state %d sc %p\n",
                    task->itt, task->state, task->sc);

      session->tt->cleanup_task(task);
      task->state = ISCSI_TASK_FREE;
      task->sc = NULL;
      /*
       * login task is preallocated so do not free
       */
      if (conn->login_task == task)
            return;

      __kfifo_put(session->cmdpool.queue, (void*)&task, sizeof(void*));

      if (sc) {
            task->sc = NULL;
            /* SCSI eh reuses commands to verify us */
            sc->SCp.ptr = NULL;
            /*
             * queue command may call this to free the task, but
             * not have setup the sc callback
             */
            if (sc->scsi_done)
                  sc->scsi_done(sc);
      }
}

void __iscsi_get_task(struct iscsi_task *task)
{
      atomic_inc(&task->refcount);
}
EXPORT_SYMBOL_GPL(__iscsi_get_task);

static void __iscsi_put_task(struct iscsi_task *task)
{
      if (atomic_dec_and_test(&task->refcount))
            iscsi_free_task(task);
}

void iscsi_put_task(struct iscsi_task *task)
{
      struct iscsi_session *session = task->conn->session;

      spin_lock_bh(&session->lock);
      __iscsi_put_task(task);
      spin_unlock_bh(&session->lock);
}
EXPORT_SYMBOL_GPL(iscsi_put_task);

/**
 * iscsi_complete_task - finish a task
 * @task: iscsi cmd task
 * @state: state to complete task with
 *
 * Must be called with session lock.
 */
static void iscsi_complete_task(struct iscsi_task *task, int state)
{
      struct iscsi_conn *conn = task->conn;

      ISCSI_DBG_SESSION(conn->session,
                    "complete task itt 0x%x state %d sc %p\n",
                    task->itt, task->state, task->sc);
      if (task->state == ISCSI_TASK_COMPLETED ||
          task->state == ISCSI_TASK_ABRT_TMF ||
          task->state == ISCSI_TASK_ABRT_SESS_RECOV)
            return;
      WARN_ON_ONCE(task->state == ISCSI_TASK_FREE);
      task->state = state;

      if (!list_empty(&task->running))
            list_del_init(&task->running);

      if (conn->task == task)
            conn->task = NULL;

      if (conn->ping_task == task)
            conn->ping_task = NULL;

      /* release get from queueing */
      __iscsi_put_task(task);
}

/*
 * session lock must be held and if not called for a task that is
 * still pending or from the xmit thread, then xmit thread must
 * be suspended.
 */
static void fail_scsi_task(struct iscsi_task *task, int err)
{
      struct iscsi_conn *conn = task->conn;
      struct scsi_cmnd *sc;
      int state;

      /*
       * if a command completes and we get a successful tmf response
       * we will hit this because the scsi eh abort code does not take
       * a ref to the task.
       */
      sc = task->sc;
      if (!sc)
            return;

      if (task->state == ISCSI_TASK_PENDING) {
            /*
             * cmd never made it to the xmit thread, so we should not count
             * the cmd in the sequencing
             */
            conn->session->queued_cmdsn--;
            /* it was never sent so just complete like normal */
            state = ISCSI_TASK_COMPLETED;
      } else if (err == DID_TRANSPORT_DISRUPTED)
            state = ISCSI_TASK_ABRT_SESS_RECOV;
      else
            state = ISCSI_TASK_ABRT_TMF;

      sc->result = err << 16;
      if (!scsi_bidi_cmnd(sc))
            scsi_set_resid(sc, scsi_bufflen(sc));
      else {
            scsi_out(sc)->resid = scsi_out(sc)->length;
            scsi_in(sc)->resid = scsi_in(sc)->length;
      }

      iscsi_complete_task(task, state);
}

static int iscsi_prep_mgmt_task(struct iscsi_conn *conn,
                        struct iscsi_task *task)
{
      struct iscsi_session *session = conn->session;
      struct iscsi_hdr *hdr = task->hdr;
      struct iscsi_nopout *nop = (struct iscsi_nopout *)hdr;

      if (conn->session->state == ISCSI_STATE_LOGGING_OUT)
            return -ENOTCONN;

      if (hdr->opcode != (ISCSI_OP_LOGIN | ISCSI_OP_IMMEDIATE) &&
          hdr->opcode != (ISCSI_OP_TEXT | ISCSI_OP_IMMEDIATE))
            nop->exp_statsn = cpu_to_be32(conn->exp_statsn);
      /*
       * pre-format CmdSN for outgoing PDU.
       */
      nop->cmdsn = cpu_to_be32(session->cmdsn);
      if (hdr->itt != RESERVED_ITT) {
            /*
             * TODO: We always use immediate, so we never hit this.
             * If we start to send tmfs or nops as non-immediate then
             * we should start checking the cmdsn numbers for mgmt tasks.
             */
            if (conn->c_stage == ISCSI_CONN_STARTED &&
                !(hdr->opcode & ISCSI_OP_IMMEDIATE)) {
                  session->queued_cmdsn++;
                  session->cmdsn++;
            }
      }

      if (session->tt->init_task && session->tt->init_task(task))
            return -EIO;

      if ((hdr->opcode & ISCSI_OPCODE_MASK) == ISCSI_OP_LOGOUT)
            session->state = ISCSI_STATE_LOGGING_OUT;

      task->state = ISCSI_TASK_RUNNING;
      ISCSI_DBG_SESSION(session, "mgmtpdu [op 0x%x hdr->itt 0x%x "
                    "datalen %d]\n", hdr->opcode & ISCSI_OPCODE_MASK,
                    hdr->itt, task->data_count);
      return 0;
}

static struct iscsi_task *
__iscsi_conn_send_pdu(struct iscsi_conn *conn, struct iscsi_hdr *hdr,
                  char *data, uint32_t data_size)
{
      struct iscsi_session *session = conn->session;
      struct iscsi_host *ihost = shost_priv(session->host);
      struct iscsi_task *task;
      itt_t itt;

      if (session->state == ISCSI_STATE_TERMINATE)
            return NULL;

      if (hdr->opcode == (ISCSI_OP_LOGIN | ISCSI_OP_IMMEDIATE) ||
          hdr->opcode == (ISCSI_OP_TEXT | ISCSI_OP_IMMEDIATE))
            /*
             * Login and Text are sent serially, in
             * request-followed-by-response sequence.
             * Same task can be used. Same ITT must be used.
             * Note that login_task is preallocated at conn_create().
             */
            task = conn->login_task;
      else {
            if (session->state != ISCSI_STATE_LOGGED_IN)
                  return NULL;

            BUG_ON(conn->c_stage == ISCSI_CONN_INITIAL_STAGE);
            BUG_ON(conn->c_stage == ISCSI_CONN_STOPPED);

            if (!__kfifo_get(session->cmdpool.queue,
                         (void*)&task, sizeof(void*)))
                  return NULL;
      }
      /*
       * released in complete pdu for task we expect a response for, and
       * released by the lld when it has transmitted the task for
       * pdus we do not expect a response for.
       */
      atomic_set(&task->refcount, 1);
      task->conn = conn;
      task->sc = NULL;
      INIT_LIST_HEAD(&task->running);
      task->state = ISCSI_TASK_PENDING;

      if (data_size) {
            memcpy(task->data, data, data_size);
            task->data_count = data_size;
      } else
            task->data_count = 0;

      if (conn->session->tt->alloc_pdu) {
            if (conn->session->tt->alloc_pdu(task, hdr->opcode)) {
                  iscsi_conn_printk(KERN_ERR, conn, "Could not allocate "
                               "pdu for mgmt task.\n");
                  goto free_task;
            }
      }

      itt = task->hdr->itt;
      task->hdr_len = sizeof(struct iscsi_hdr);
      memcpy(task->hdr, hdr, sizeof(struct iscsi_hdr));

      if (hdr->itt != RESERVED_ITT) {
            if (session->tt->parse_pdu_itt)
                  task->hdr->itt = itt;
            else
                  task->hdr->itt = build_itt(task->itt,
                                       task->conn->session->age);
      }

      if (!ihost->workq) {
            if (iscsi_prep_mgmt_task(conn, task))
                  goto free_task;

            if (session->tt->xmit_task(task))
                  goto free_task;
      } else {
            list_add_tail(&task->running, &conn->mgmtqueue);
            iscsi_conn_queue_work(conn);
      }

      return task;

free_task:
      __iscsi_put_task(task);
      return NULL;
}

int iscsi_conn_send_pdu(struct iscsi_cls_conn *cls_conn, struct iscsi_hdr *hdr,
                  char *data, uint32_t data_size)
{
      struct iscsi_conn *conn = cls_conn->dd_data;
      struct iscsi_session *session = conn->session;
      int err = 0;

      spin_lock_bh(&session->lock);
      if (!__iscsi_conn_send_pdu(conn, hdr, data, data_size))
            err = -EPERM;
      spin_unlock_bh(&session->lock);
      return err;
}
EXPORT_SYMBOL_GPL(iscsi_conn_send_pdu);

/**
 * iscsi_cmd_rsp - SCSI Command Response processing
 * @conn: iscsi connection
 * @hdr: iscsi header
 * @task: scsi command task
 * @data: cmd data buffer
 * @datalen: len of buffer
 *
 * iscsi_cmd_rsp sets up the scsi_cmnd fields based on the PDU and
 * then completes the command and task.
 **/
static void iscsi_scsi_cmd_rsp(struct iscsi_conn *conn, struct iscsi_hdr *hdr,
                         struct iscsi_task *task, char *data,
                         int datalen)
{
      struct iscsi_cmd_rsp *rhdr = (struct iscsi_cmd_rsp *)hdr;
      struct iscsi_session *session = conn->session;
      struct scsi_cmnd *sc = task->sc;

      iscsi_update_cmdsn(session, (struct iscsi_nopin*)rhdr);
      conn->exp_statsn = be32_to_cpu(rhdr->statsn) + 1;

      sc->result = (DID_OK << 16) | rhdr->cmd_status;

      if (rhdr->response != ISCSI_STATUS_CMD_COMPLETED) {
            sc->result = DID_ERROR << 16;
            goto out;
      }

      if (rhdr->cmd_status == SAM_STAT_CHECK_CONDITION) {
            uint16_t senselen;

            if (datalen < 2) {
invalid_datalen:
                  iscsi_conn_printk(KERN_ERR,  conn,
                               "Got CHECK_CONDITION but invalid data "
                               "buffer size of %d\n", datalen);
                  sc->result = DID_BAD_TARGET << 16;
                  goto out;
            }

            senselen = get_unaligned_be16(data);
            if (datalen < senselen)
                  goto invalid_datalen;

            memcpy(sc->sense_buffer, data + 2,
                   min_t(uint16_t, senselen, SCSI_SENSE_BUFFERSIZE));
            ISCSI_DBG_SESSION(session, "copied %d bytes of sense\n",
                          min_t(uint16_t, senselen,
                          SCSI_SENSE_BUFFERSIZE));
      }

      if (rhdr->flags & (ISCSI_FLAG_CMD_BIDI_UNDERFLOW |
                     ISCSI_FLAG_CMD_BIDI_OVERFLOW)) {
            int res_count = be32_to_cpu(rhdr->bi_residual_count);

            if (scsi_bidi_cmnd(sc) && res_count > 0 &&
                        (rhdr->flags & ISCSI_FLAG_CMD_BIDI_OVERFLOW ||
                         res_count <= scsi_in(sc)->length))
                  scsi_in(sc)->resid = res_count;
            else
                  sc->result = (DID_BAD_TARGET << 16) | rhdr->cmd_status;
      }

      if (rhdr->flags & (ISCSI_FLAG_CMD_UNDERFLOW |
                         ISCSI_FLAG_CMD_OVERFLOW)) {
            int res_count = be32_to_cpu(rhdr->residual_count);

            if (res_count > 0 &&
                (rhdr->flags & ISCSI_FLAG_CMD_OVERFLOW ||
                 res_count <= scsi_bufflen(sc)))
                  /* write side for bidi or uni-io set_resid */
                  scsi_set_resid(sc, res_count);
            else
                  sc->result = (DID_BAD_TARGET << 16) | rhdr->cmd_status;
      }
out:
      ISCSI_DBG_SESSION(session, "cmd rsp done [sc %p res %d itt 0x%x]\n",
                    sc, sc->result, task->itt);
      conn->scsirsp_pdus_cnt++;
      iscsi_complete_task(task, ISCSI_TASK_COMPLETED);
}

/**
 * iscsi_data_in_rsp - SCSI Data-In Response processing
 * @conn: iscsi connection
 * @hdr:  iscsi pdu
 * @task: scsi command task
 **/
static void
iscsi_data_in_rsp(struct iscsi_conn *conn, struct iscsi_hdr *hdr,
              struct iscsi_task *task)
{
      struct iscsi_data_rsp *rhdr = (struct iscsi_data_rsp *)hdr;
      struct scsi_cmnd *sc = task->sc;

      if (!(rhdr->flags & ISCSI_FLAG_DATA_STATUS))
            return;

      iscsi_update_cmdsn(conn->session, (struct iscsi_nopin *)hdr);
      sc->result = (DID_OK << 16) | rhdr->cmd_status;
      conn->exp_statsn = be32_to_cpu(rhdr->statsn) + 1;
      if (rhdr->flags & (ISCSI_FLAG_DATA_UNDERFLOW |
                         ISCSI_FLAG_DATA_OVERFLOW)) {
            int res_count = be32_to_cpu(rhdr->residual_count);

            if (res_count > 0 &&
                (rhdr->flags & ISCSI_FLAG_CMD_OVERFLOW ||
                 res_count <= scsi_in(sc)->length))
                  scsi_in(sc)->resid = res_count;
            else
                  sc->result = (DID_BAD_TARGET << 16) | rhdr->cmd_status;
      }

      ISCSI_DBG_SESSION(conn->session, "data in with status done "
                    "[sc %p res %d itt 0x%x]\n",
                    sc, sc->result, task->itt);
      conn->scsirsp_pdus_cnt++;
      iscsi_complete_task(task, ISCSI_TASK_COMPLETED);
}

static void iscsi_tmf_rsp(struct iscsi_conn *conn, struct iscsi_hdr *hdr)
{
      struct iscsi_tm_rsp *tmf = (struct iscsi_tm_rsp *)hdr;

      conn->exp_statsn = be32_to_cpu(hdr->statsn) + 1;
      conn->tmfrsp_pdus_cnt++;

      if (conn->tmf_state != TMF_QUEUED)
            return;

      if (tmf->response == ISCSI_TMF_RSP_COMPLETE)
            conn->tmf_state = TMF_SUCCESS;
      else if (tmf->response == ISCSI_TMF_RSP_NO_TASK)
            conn->tmf_state = TMF_NOT_FOUND;
      else
            conn->tmf_state = TMF_FAILED;
      wake_up(&conn->ehwait);
}

static void iscsi_send_nopout(struct iscsi_conn *conn, struct iscsi_nopin *rhdr)
{
        struct iscsi_nopout hdr;
      struct iscsi_task *task;

      if (!rhdr && conn->ping_task)
            return;

      memset(&hdr, 0, sizeof(struct iscsi_nopout));
      hdr.opcode = ISCSI_OP_NOOP_OUT | ISCSI_OP_IMMEDIATE;
      hdr.flags = ISCSI_FLAG_CMD_FINAL;

      if (rhdr) {
            memcpy(hdr.lun, rhdr->lun, 8);
            hdr.ttt = rhdr->ttt;
            hdr.itt = RESERVED_ITT;
      } else
            hdr.ttt = RESERVED_ITT;

      task = __iscsi_conn_send_pdu(conn, (struct iscsi_hdr *)&hdr, NULL, 0);
      if (!task)
            iscsi_conn_printk(KERN_ERR, conn, "Could not send nopout\n");
      else if (!rhdr) {
            /* only track our nops */
            conn->ping_task = task;
            conn->last_ping = jiffies;
      }
}

static int iscsi_handle_reject(struct iscsi_conn *conn, struct iscsi_hdr *hdr,
                         char *data, int datalen)
{
      struct iscsi_reject *reject = (struct iscsi_reject *)hdr;
      struct iscsi_hdr rejected_pdu;

      conn->exp_statsn = be32_to_cpu(reject->statsn) + 1;

      if (reject->reason == ISCSI_REASON_DATA_DIGEST_ERROR) {
            if (ntoh24(reject->dlength) > datalen)
                  return ISCSI_ERR_PROTO;

            if (ntoh24(reject->dlength) >= sizeof(struct iscsi_hdr)) {
                  memcpy(&rejected_pdu, data, sizeof(struct iscsi_hdr));
                  iscsi_conn_printk(KERN_ERR, conn,
                                "pdu (op 0x%x) rejected "
                                "due to DataDigest error.\n",
                                rejected_pdu.opcode);
            }
      }
      return 0;
}

/**
 * iscsi_itt_to_task - look up task by itt
 * @conn: iscsi connection
 * @itt: itt
 *
 * This should be used for mgmt tasks like login and nops, or if
 * the LDD's itt space does not include the session age.
 *
 * The session lock must be held.
 */
struct iscsi_task *iscsi_itt_to_task(struct iscsi_conn *conn, itt_t itt)
{
      struct iscsi_session *session = conn->session;
      int i;

      if (itt == RESERVED_ITT)
            return NULL;

      if (session->tt->parse_pdu_itt)
            session->tt->parse_pdu_itt(conn, itt, &i, NULL);
      else
            i = get_itt(itt);
      if (i >= session->cmds_max)
            return NULL;

      return session->cmds[i];
}
EXPORT_SYMBOL_GPL(iscsi_itt_to_task);

/**
 * __iscsi_complete_pdu - complete pdu
 * @conn: iscsi conn
 * @hdr: iscsi header
 * @data: data buffer
 * @datalen: len of data buffer
 *
 * Completes pdu processing by freeing any resources allocated at
 * queuecommand or send generic. session lock must be held and verify
 * itt must have been called.
 */
int __iscsi_complete_pdu(struct iscsi_conn *conn, struct iscsi_hdr *hdr,
                   char *data, int datalen)
{
      struct iscsi_session *session = conn->session;
      int opcode = hdr->opcode & ISCSI_OPCODE_MASK, rc = 0;
      struct iscsi_task *task;
      uint32_t itt;

      conn->last_recv = jiffies;
      rc = iscsi_verify_itt(conn, hdr->itt);
      if (rc)
            return rc;

      if (hdr->itt != RESERVED_ITT)
            itt = get_itt(hdr->itt);
      else
            itt = ~0U;

      ISCSI_DBG_SESSION(session, "[op 0x%x cid %d itt 0x%x len %d]\n",
                    opcode, conn->id, itt, datalen);

      if (itt == ~0U) {
            iscsi_update_cmdsn(session, (struct iscsi_nopin*)hdr);

            switch(opcode) {
            case ISCSI_OP_NOOP_IN:
                  if (datalen) {
                        rc = ISCSI_ERR_PROTO;
                        break;
                  }

                  if (hdr->ttt == cpu_to_be32(ISCSI_RESERVED_TAG))
                        break;

                  iscsi_send_nopout(conn, (struct iscsi_nopin*)hdr);
                  break;
            case ISCSI_OP_REJECT:
                  rc = iscsi_handle_reject(conn, hdr, data, datalen);
                  break;
            case ISCSI_OP_ASYNC_EVENT:
                  conn->exp_statsn = be32_to_cpu(hdr->statsn) + 1;
                  if (iscsi_recv_pdu(conn->cls_conn, hdr, data, datalen))
                        rc = ISCSI_ERR_CONN_FAILED;
                  break;
            default:
                  rc = ISCSI_ERR_BAD_OPCODE;
                  break;
            }
            goto out;
      }

      switch(opcode) {
      case ISCSI_OP_SCSI_CMD_RSP:
      case ISCSI_OP_SCSI_DATA_IN:
            task = iscsi_itt_to_ctask(conn, hdr->itt);
            if (!task)
                  return ISCSI_ERR_BAD_ITT;
            task->last_xfer = jiffies;
            break;
      case ISCSI_OP_R2T:
            /*
             * LLD handles R2Ts if they need to.
             */
            return 0;
      case ISCSI_OP_LOGOUT_RSP:
      case ISCSI_OP_LOGIN_RSP:
      case ISCSI_OP_TEXT_RSP:
      case ISCSI_OP_SCSI_TMFUNC_RSP:
      case ISCSI_OP_NOOP_IN:
            task = iscsi_itt_to_task(conn, hdr->itt);
            if (!task)
                  return ISCSI_ERR_BAD_ITT;
            break;
      default:
            return ISCSI_ERR_BAD_OPCODE;
      }

      switch(opcode) {
      case ISCSI_OP_SCSI_CMD_RSP:
            iscsi_scsi_cmd_rsp(conn, hdr, task, data, datalen);
            break;
      case ISCSI_OP_SCSI_DATA_IN:
            iscsi_data_in_rsp(conn, hdr, task);
            break;
      case ISCSI_OP_LOGOUT_RSP:
            iscsi_update_cmdsn(session, (struct iscsi_nopin*)hdr);
            if (datalen) {
                  rc = ISCSI_ERR_PROTO;
                  break;
            }
            conn->exp_statsn = be32_to_cpu(hdr->statsn) + 1;
            goto recv_pdu;
      case ISCSI_OP_LOGIN_RSP:
      case ISCSI_OP_TEXT_RSP:
            iscsi_update_cmdsn(session, (struct iscsi_nopin*)hdr);
            /*
             * login related PDU's exp_statsn is handled in
             * userspace
             */
            goto recv_pdu;
      case ISCSI_OP_SCSI_TMFUNC_RSP:
            iscsi_update_cmdsn(session, (struct iscsi_nopin*)hdr);
            if (datalen) {
                  rc = ISCSI_ERR_PROTO;
                  break;
            }

            iscsi_tmf_rsp(conn, hdr);
            iscsi_complete_task(task, ISCSI_TASK_COMPLETED);
            break;
      case ISCSI_OP_NOOP_IN:
            iscsi_update_cmdsn(session, (struct iscsi_nopin*)hdr);
            if (hdr->ttt != cpu_to_be32(ISCSI_RESERVED_TAG) || datalen) {
                  rc = ISCSI_ERR_PROTO;
                  break;
            }
            conn->exp_statsn = be32_to_cpu(hdr->statsn) + 1;

            if (conn->ping_task != task)
                  /*
                   * If this is not in response to one of our
                   * nops then it must be from userspace.
                   */
                  goto recv_pdu;

            mod_timer(&conn->transport_timer, jiffies + conn->recv_timeout);
            iscsi_complete_task(task, ISCSI_TASK_COMPLETED);
            break;
      default:
            rc = ISCSI_ERR_BAD_OPCODE;
            break;
      }

out:
      return rc;
recv_pdu:
      if (iscsi_recv_pdu(conn->cls_conn, hdr, data, datalen))
            rc = ISCSI_ERR_CONN_FAILED;
      iscsi_complete_task(task, ISCSI_TASK_COMPLETED);
      return rc;
}
EXPORT_SYMBOL_GPL(__iscsi_complete_pdu);

int iscsi_complete_pdu(struct iscsi_conn *conn, struct iscsi_hdr *hdr,
                   char *data, int datalen)
{
      int rc;

      spin_lock(&conn->session->lock);
      rc = __iscsi_complete_pdu(conn, hdr, data, datalen);
      spin_unlock(&conn->session->lock);
      return rc;
}
EXPORT_SYMBOL_GPL(iscsi_complete_pdu);

int iscsi_verify_itt(struct iscsi_conn *conn, itt_t itt)
{
      struct iscsi_session *session = conn->session;
      int age = 0, i = 0;

      if (itt == RESERVED_ITT)
            return 0;

      if (session->tt->parse_pdu_itt)
            session->tt->parse_pdu_itt(conn, itt, &i, &age);
      else {
            i = get_itt(itt);
            age = ((__force u32)itt >> ISCSI_AGE_SHIFT) & ISCSI_AGE_MASK;
      }

      if (age != session->age) {
            iscsi_conn_printk(KERN_ERR, conn,
                          "received itt %x expected session age (%x)\n",
                          (__force u32)itt, session->age);
            return ISCSI_ERR_BAD_ITT;
      }

      if (i >= session->cmds_max) {
            iscsi_conn_printk(KERN_ERR, conn,
                          "received invalid itt index %u (max cmds "
                           "%u.\n", i, session->cmds_max);
            return ISCSI_ERR_BAD_ITT;
      }
      return 0;
}
EXPORT_SYMBOL_GPL(iscsi_verify_itt);

/**
 * iscsi_itt_to_ctask - look up ctask by itt
 * @conn: iscsi connection
 * @itt: itt
 *
 * This should be used for cmd tasks.
 *
 * The session lock must be held.
 */
struct iscsi_task *iscsi_itt_to_ctask(struct iscsi_conn *conn, itt_t itt)
{
      struct iscsi_task *task;

      if (iscsi_verify_itt(conn, itt))
            return NULL;

      task = iscsi_itt_to_task(conn, itt);
      if (!task || !task->sc)
            return NULL;

      if (task->sc->SCp.phase != conn->session->age) {
            iscsi_session_printk(KERN_ERR, conn->session,
                          "task's session age %d, expected %d\n",
                          task->sc->SCp.phase, conn->session->age);
            return NULL;
      }

      return task;
}
EXPORT_SYMBOL_GPL(iscsi_itt_to_ctask);

void iscsi_session_failure(struct iscsi_session *session,
                     enum iscsi_err err)
{
      struct iscsi_conn *conn;
      struct device *dev;
      unsigned long flags;

      spin_lock_irqsave(&session->lock, flags);
      conn = session->leadconn;
      if (session->state == ISCSI_STATE_TERMINATE || !conn) {
            spin_unlock_irqrestore(&session->lock, flags);
            return;
      }

      dev = get_device(&conn->cls_conn->dev);
      spin_unlock_irqrestore(&session->lock, flags);
      if (!dev)
              return;
      /*
       * if the host is being removed bypass the connection
       * recovery initialization because we are going to kill
       * the session.
       */
      if (err == ISCSI_ERR_INVALID_HOST)
            iscsi_conn_error_event(conn->cls_conn, err);
      else
            iscsi_conn_failure(conn, err);
      put_device(dev);
}
EXPORT_SYMBOL_GPL(iscsi_session_failure);

void iscsi_conn_failure(struct iscsi_conn *conn, enum iscsi_err err)
{
      struct iscsi_session *session = conn->session;
      unsigned long flags;

      spin_lock_irqsave(&session->lock, flags);
      if (session->state == ISCSI_STATE_FAILED) {
            spin_unlock_irqrestore(&session->lock, flags);
            return;
      }

      if (conn->stop_stage == 0)
            session->state = ISCSI_STATE_FAILED;
      spin_unlock_irqrestore(&session->lock, flags);

      set_bit(ISCSI_SUSPEND_BIT, &conn->suspend_tx);
      set_bit(ISCSI_SUSPEND_BIT, &conn->suspend_rx);
      iscsi_conn_error_event(conn->cls_conn, err);
}
EXPORT_SYMBOL_GPL(iscsi_conn_failure);

static int iscsi_check_cmdsn_window_closed(struct iscsi_conn *conn)
{
      struct iscsi_session *session = conn->session;

      /*
       * Check for iSCSI window and take care of CmdSN wrap-around
       */
      if (!iscsi_sna_lte(session->queued_cmdsn, session->max_cmdsn)) {
            ISCSI_DBG_SESSION(session, "iSCSI CmdSN closed. ExpCmdSn "
                          "%u MaxCmdSN %u CmdSN %u/%u\n",
                          session->exp_cmdsn, session->max_cmdsn,
                          session->cmdsn, session->queued_cmdsn);
            return -ENOSPC;
      }
      return 0;
}

static int iscsi_xmit_task(struct iscsi_conn *conn)
{
      struct iscsi_task *task = conn->task;
      int rc;

      __iscsi_get_task(task);
      spin_unlock_bh(&conn->session->lock);
      rc = conn->session->tt->xmit_task(task);
      spin_lock_bh(&conn->session->lock);
      if (!rc) {
            /* done with this task */
            task->last_xfer = jiffies;
            conn->task = NULL;
      }
      __iscsi_put_task(task);
      return rc;
}

/**
 * iscsi_requeue_task - requeue task to run from session workqueue
 * @task: task to requeue
 *
 * LLDs that need to run a task from the session workqueue should call
 * this. The session lock must be held. This should only be called
 * by software drivers.
 */
void iscsi_requeue_task(struct iscsi_task *task)
{
      struct iscsi_conn *conn = task->conn;

      /*
       * this may be on the requeue list already if the xmit_task callout
       * is handling the r2ts while we are adding new ones
       */
      if (list_empty(&task->running))
            list_add_tail(&task->running, &conn->requeue);
      iscsi_conn_queue_work(conn);
}
EXPORT_SYMBOL_GPL(iscsi_requeue_task);

/**
 * iscsi_data_xmit - xmit any command into the scheduled connection
 * @conn: iscsi connection
 *
 * Notes:
 *    The function can return -EAGAIN in which case the caller must
 *    re-schedule it again later or recover. '0' return code means
 *    successful xmit.
 **/
static int iscsi_data_xmit(struct iscsi_conn *conn)
{
      int rc = 0;

      spin_lock_bh(&conn->session->lock);
      if (unlikely(conn->suspend_tx)) {
            ISCSI_DBG_SESSION(conn->session, "Tx suspended!\n");
            spin_unlock_bh(&conn->session->lock);
            return -ENODATA;
      }

      if (conn->task) {
            rc = iscsi_xmit_task(conn);
              if (rc)
                    goto again;
      }

      /*
       * process mgmt pdus like nops before commands since we should
       * only have one nop-out as a ping from us and targets should not
       * overflow us with nop-ins
       */
check_mgmt:
      while (!list_empty(&conn->mgmtqueue)) {
            conn->task = list_entry(conn->mgmtqueue.next,
                               struct iscsi_task, running);
            list_del_init(&conn->task->running);
            if (iscsi_prep_mgmt_task(conn, conn->task)) {
                  __iscsi_put_task(conn->task);
                  conn->task = NULL;
                  continue;
            }
            rc = iscsi_xmit_task(conn);
            if (rc)
                  goto again;
      }

      /* process pending command queue */
      while (!list_empty(&conn->cmdqueue)) {
            if (conn->tmf_state == TMF_QUEUED)
                  break;

            conn->task = list_entry(conn->cmdqueue.next,
                               struct iscsi_task, running);
            list_del_init(&conn->task->running);
            if (conn->session->state == ISCSI_STATE_LOGGING_OUT) {
                  fail_scsi_task(conn->task, DID_IMM_RETRY);
                  continue;
            }
            rc = iscsi_prep_scsi_cmd_pdu(conn->task);
            if (rc) {
                  if (rc == -ENOMEM) {
                        list_add_tail(&conn->task->running,
                                    &conn->cmdqueue);
                        conn->task = NULL;
                        goto again;
                  } else
                        fail_scsi_task(conn->task, DID_ABORT);
                  continue;
            }
            rc = iscsi_xmit_task(conn);
            if (rc)
                  goto again;
            /*
             * we could continuously get new task requests so
             * we need to check the mgmt queue for nops that need to
             * be sent to aviod starvation
             */
            if (!list_empty(&conn->mgmtqueue))
                  goto check_mgmt;
      }

      while (!list_empty(&conn->requeue)) {
            if (conn->session->fast_abort && conn->tmf_state != TMF_INITIAL)
                  break;

            /*
             * we always do fastlogout - conn stop code will clean up.
             */
            if (conn->session->state == ISCSI_STATE_LOGGING_OUT)
                  break;

            conn->task = list_entry(conn->requeue.next,
                               struct iscsi_task, running);
            list_del_init(&conn->task->running);
            conn->task->state = ISCSI_TASK_RUNNING;
            rc = iscsi_xmit_task(conn);
            if (rc)
                  goto again;
            if (!list_empty(&conn->mgmtqueue))
                  goto check_mgmt;
      }
      spin_unlock_bh(&conn->session->lock);
      return -ENODATA;

again:
      if (unlikely(conn->suspend_tx))
            rc = -ENODATA;
      spin_unlock_bh(&conn->session->lock);
      return rc;
}

static void iscsi_xmitworker(struct work_struct *work)
{
      struct iscsi_conn *conn =
            container_of(work, struct iscsi_conn, xmitwork);
      int rc;
      /*
       * serialize Xmit worker on a per-connection basis.
       */
      do {
            rc = iscsi_data_xmit(conn);
      } while (rc >= 0 || rc == -EAGAIN);
}

static inline struct iscsi_task *iscsi_alloc_task(struct iscsi_conn *conn,
                                      struct scsi_cmnd *sc)
{
      struct iscsi_task *task;

      if (!__kfifo_get(conn->session->cmdpool.queue,
                   (void *) &task, sizeof(void *)))
            return NULL;

      sc->SCp.phase = conn->session->age;
      sc->SCp.ptr = (char *) task;

      atomic_set(&task->refcount, 1);
      task->state = ISCSI_TASK_PENDING;
      task->conn = conn;
      task->sc = sc;
      task->have_checked_conn = false;
      task->last_timeout = jiffies;
      task->last_xfer = jiffies;
      INIT_LIST_HEAD(&task->running);
      return task;
}

enum {
      FAILURE_BAD_HOST = 1,
      FAILURE_SESSION_FAILED,
      FAILURE_SESSION_FREED,
      FAILURE_WINDOW_CLOSED,
      FAILURE_OOM,
      FAILURE_SESSION_TERMINATE,
      FAILURE_SESSION_IN_RECOVERY,
      FAILURE_SESSION_RECOVERY_TIMEOUT,
      FAILURE_SESSION_LOGGING_OUT,
      FAILURE_SESSION_NOT_READY,
};

int iscsi_queuecommand(struct scsi_cmnd *sc, void (*done)(struct scsi_cmnd *))
{
      struct iscsi_cls_session *cls_session;
      struct Scsi_Host *host;
      struct iscsi_host *ihost;
      int reason = 0;
      struct iscsi_session *session;
      struct iscsi_conn *conn;
      struct iscsi_task *task = NULL;

      sc->scsi_done = done;
      sc->result = 0;
      sc->SCp.ptr = NULL;

      host = sc->device->host;
      ihost = shost_priv(host);
      spin_unlock(host->host_lock);

      cls_session = starget_to_session(scsi_target(sc->device));
      session = cls_session->dd_data;
      spin_lock(&session->lock);

      reason = iscsi_session_chkready(cls_session);
      if (reason) {
            sc->result = reason;
            goto fault;
      }

      if (session->state != ISCSI_STATE_LOGGED_IN) {
            /*
             * to handle the race between when we set the recovery state
             * and block the session we requeue here (commands could
             * be entering our queuecommand while a block is starting
             * up because the block code is not locked)
             */
            switch (session->state) {
            case ISCSI_STATE_FAILED:
            case ISCSI_STATE_IN_RECOVERY:
                  reason = FAILURE_SESSION_IN_RECOVERY;
                  sc->result = DID_IMM_RETRY << 16;
                  break;
            case ISCSI_STATE_LOGGING_OUT:
                  reason = FAILURE_SESSION_LOGGING_OUT;
                  sc->result = DID_IMM_RETRY << 16;
                  break;
            case ISCSI_STATE_RECOVERY_FAILED:
                  reason = FAILURE_SESSION_RECOVERY_TIMEOUT;
                  sc->result = DID_TRANSPORT_FAILFAST << 16;
                  break;
            case ISCSI_STATE_TERMINATE:
                  reason = FAILURE_SESSION_TERMINATE;
                  sc->result = DID_NO_CONNECT << 16;
                  break;
            default:
                  reason = FAILURE_SESSION_FREED;
                  sc->result = DID_NO_CONNECT << 16;
            }
            goto fault;
      }

      conn = session->leadconn;
      if (!conn) {
            reason = FAILURE_SESSION_FREED;
            sc->result = DID_NO_CONNECT << 16;
            goto fault;
      }

      if (iscsi_check_cmdsn_window_closed(conn)) {
            reason = FAILURE_WINDOW_CLOSED;
            goto reject;
      }

      task = iscsi_alloc_task(conn, sc);
      if (!task) {
            reason = FAILURE_OOM;
            goto reject;
      }

      if (!ihost->workq) {
            reason = iscsi_prep_scsi_cmd_pdu(task);
            if (reason) {
                  if (reason == -ENOMEM) {
                        reason = FAILURE_OOM;
                        goto prepd_reject;
                  } else {
                        sc->result = DID_ABORT << 16;
                        goto prepd_fault;
                  }
            }
            if (session->tt->xmit_task(task)) {
                  reason = FAILURE_SESSION_NOT_READY;
                  goto prepd_reject;
            }
      } else {
            list_add_tail(&task->running, &conn->cmdqueue);
            iscsi_conn_queue_work(conn);
      }

      session->queued_cmdsn++;
      spin_unlock(&session->lock);
      spin_lock(host->host_lock);
      return 0;

prepd_reject:
      sc->scsi_done = NULL;
      iscsi_complete_task(task, ISCSI_TASK_COMPLETED);
reject:
      spin_unlock(&session->lock);
      ISCSI_DBG_SESSION(session, "cmd 0x%x rejected (%d)\n",
                    sc->cmnd[0], reason);
      spin_lock(host->host_lock);
      return SCSI_MLQUEUE_TARGET_BUSY;

prepd_fault:
      sc->scsi_done = NULL;
      iscsi_complete_task(task, ISCSI_TASK_COMPLETED);
fault:
      spin_unlock(&session->lock);
      ISCSI_DBG_SESSION(session, "iscsi: cmd 0x%x is not queued (%d)\n",
                    sc->cmnd[0], reason);
      if (!scsi_bidi_cmnd(sc))
            scsi_set_resid(sc, scsi_bufflen(sc));
      else {
            scsi_out(sc)->resid = scsi_out(sc)->length;
            scsi_in(sc)->resid = scsi_in(sc)->length;
      }
      done(sc);
      spin_lock(host->host_lock);
      return 0;
}
EXPORT_SYMBOL_GPL(iscsi_queuecommand);

int iscsi_change_queue_depth(struct scsi_device *sdev, int depth)
{
      scsi_adjust_queue_depth(sdev, scsi_get_tag_type(sdev), depth);
      return sdev->queue_depth;
}
EXPORT_SYMBOL_GPL(iscsi_change_queue_depth);

int iscsi_target_alloc(struct scsi_target *starget)
{
      struct iscsi_cls_session *cls_session = starget_to_session(starget);
      struct iscsi_session *session = cls_session->dd_data;

      starget->can_queue = session->scsi_cmds_max;
      return 0;
}
EXPORT_SYMBOL_GPL(iscsi_target_alloc);

void iscsi_session_recovery_timedout(struct iscsi_cls_session *cls_session)
{
      struct iscsi_session *session = cls_session->dd_data;

      spin_lock_bh(&session->lock);
      if (session->state != ISCSI_STATE_LOGGED_IN) {
            session->state = ISCSI_STATE_RECOVERY_FAILED;
            if (session->leadconn)
                  wake_up(&session->leadconn->ehwait);
      }
      spin_unlock_bh(&session->lock);
}
EXPORT_SYMBOL_GPL(iscsi_session_recovery_timedout);

int iscsi_eh_target_reset(struct scsi_cmnd *sc)
{
      struct iscsi_cls_session *cls_session;
      struct iscsi_session *session;
      struct iscsi_conn *conn;

      cls_session = starget_to_session(scsi_target(sc->device));
      session = cls_session->dd_data;
      conn = session->leadconn;

      mutex_lock(&session->eh_mutex);
      spin_lock_bh(&session->lock);
      if (session->state == ISCSI_STATE_TERMINATE) {
failed:
            ISCSI_DBG_EH(session,
                       "failing target reset: Could not log back into "
                       "target [age %d]\n",
                       session->age);
            spin_unlock_bh(&session->lock);
            mutex_unlock(&session->eh_mutex);
            return FAILED;
      }

      spin_unlock_bh(&session->lock);
      mutex_unlock(&session->eh_mutex);
      /*
       * we drop the lock here but the leadconn cannot be destoyed while
       * we are in the scsi eh
       */
      iscsi_conn_failure(conn, ISCSI_ERR_CONN_FAILED);

      ISCSI_DBG_EH(session, "wait for relogin\n");
      wait_event_interruptible(conn->ehwait,
                         session->state == ISCSI_STATE_TERMINATE ||
                         session->state == ISCSI_STATE_LOGGED_IN ||
                         session->state == ISCSI_STATE_RECOVERY_FAILED);
      if (signal_pending(current))
            flush_signals(current);

      mutex_lock(&session->eh_mutex);
      spin_lock_bh(&session->lock);
      if (session->state == ISCSI_STATE_LOGGED_IN) {
            ISCSI_DBG_EH(session,
                       "target reset succeeded\n");
      } else
            goto failed;
      spin_unlock_bh(&session->lock);
      mutex_unlock(&session->eh_mutex);
      return SUCCESS;
}
EXPORT_SYMBOL_GPL(iscsi_eh_target_reset);

static void iscsi_tmf_timedout(unsigned long data)
{
      struct iscsi_conn *conn = (struct iscsi_conn *)data;
      struct iscsi_session *session = conn->session;

      spin_lock(&session->lock);
      if (conn->tmf_state == TMF_QUEUED) {
            conn->tmf_state = TMF_TIMEDOUT;
            ISCSI_DBG_EH(session, "tmf timedout\n");
            /* unblock eh_abort() */
            wake_up(&conn->ehwait);
      }
      spin_unlock(&session->lock);
}

static int iscsi_exec_task_mgmt_fn(struct iscsi_conn *conn,
                           struct iscsi_tm *hdr, int age,
                           int timeout)
{
      struct iscsi_session *session = conn->session;
      struct iscsi_task *task;

      task = __iscsi_conn_send_pdu(conn, (struct iscsi_hdr *)hdr,
                              NULL, 0);
      if (!task) {
            spin_unlock_bh(&session->lock);
            iscsi_conn_failure(conn, ISCSI_ERR_CONN_FAILED);
            spin_lock_bh(&session->lock);
            ISCSI_DBG_EH(session, "tmf exec failure\n");
            return -EPERM;
      }
      conn->tmfcmd_pdus_cnt++;
      conn->tmf_timer.expires = timeout * HZ + jiffies;
      conn->tmf_timer.function = iscsi_tmf_timedout;
      conn->tmf_timer.data = (unsigned long)conn;
      add_timer(&conn->tmf_timer);
      ISCSI_DBG_EH(session, "tmf set timeout\n");

      spin_unlock_bh(&session->lock);
      mutex_unlock(&session->eh_mutex);

      /*
       * block eh thread until:
       *
       * 1) tmf response
       * 2) tmf timeout
       * 3) session is terminated or restarted or userspace has
       * given up on recovery
       */
      wait_event_interruptible(conn->ehwait, age != session->age ||
                         session->state != ISCSI_STATE_LOGGED_IN ||
                         conn->tmf_state != TMF_QUEUED);
      if (signal_pending(current))
            flush_signals(current);
      del_timer_sync(&conn->tmf_timer);

      mutex_lock(&session->eh_mutex);
      spin_lock_bh(&session->lock);
      /* if the session drops it will clean up the task */
      if (age != session->age ||
          session->state != ISCSI_STATE_LOGGED_IN)
            return -ENOTCONN;
      return 0;
}

/*
 * Fail commands. session lock held and recv side suspended and xmit
 * thread flushed
 */
static void fail_scsi_tasks(struct iscsi_conn *conn, unsigned lun,
                      int error)
{
      struct iscsi_task *task;
      int i;

      for (i = 0; i < conn->session->cmds_max; i++) {
            task = conn->session->cmds[i];
            if (!task->sc || task->state == ISCSI_TASK_FREE)
                  continue;

            if (lun != -1 && lun != task->sc->device->lun)
                  continue;

            ISCSI_DBG_SESSION(conn->session,
                          "failing sc %p itt 0x%x state %d\n",
                          task->sc, task->itt, task->state);
            fail_scsi_task(task, error);
      }
}

void iscsi_suspend_tx(struct iscsi_conn *conn)
{
      struct Scsi_Host *shost = conn->session->host;
      struct iscsi_host *ihost = shost_priv(shost);

      set_bit(ISCSI_SUSPEND_BIT, &conn->suspend_tx);
      if (ihost->workq)
            flush_workqueue(ihost->workq);
}
EXPORT_SYMBOL_GPL(iscsi_suspend_tx);

static void iscsi_start_tx(struct iscsi_conn *conn)
{
      clear_bit(ISCSI_SUSPEND_BIT, &conn->suspend_tx);
      iscsi_conn_queue_work(conn);
}

/*
 * We want to make sure a ping is in flight. It has timed out.
 * And we are not busy processing a pdu that is making
 * progress but got started before the ping and is taking a while
 * to complete so the ping is just stuck behind it in a queue.
 */
static int iscsi_has_ping_timed_out(struct iscsi_conn *conn)
{
      if (conn->ping_task &&
          time_before_eq(conn->last_recv + (conn->recv_timeout * HZ) +
                     (conn->ping_timeout * HZ), jiffies))
            return 1;
      else
            return 0;
}

static enum blk_eh_timer_return iscsi_eh_cmd_timed_out(struct scsi_cmnd *sc)
{
      enum blk_eh_timer_return rc = BLK_EH_NOT_HANDLED;
      struct iscsi_task *task = NULL;
      struct iscsi_cls_session *cls_session;
      struct iscsi_session *session;
      struct iscsi_conn *conn;

      cls_session = starget_to_session(scsi_target(sc->device));
      session = cls_session->dd_data;

      ISCSI_DBG_EH(session, "scsi cmd %p timedout\n", sc);

      spin_lock(&session->lock);
      if (session->state != ISCSI_STATE_LOGGED_IN) {
            /*
             * We are probably in the middle of iscsi recovery so let
             * that complete and handle the error.
             */
            rc = BLK_EH_RESET_TIMER;
            goto done;
      }

      conn = session->leadconn;
      if (!conn) {
            /* In the middle of shuting down */
            rc = BLK_EH_RESET_TIMER;
            goto done;
      }

      task = (struct iscsi_task *)sc->SCp.ptr;
      if (!task)
            goto done;
      /*
       * If we have sent (at least queued to the network layer) a pdu or
       * recvd one for the task since the last timeout ask for
       * more time. If on the next timeout we have not made progress
       * we can check if it is the task or connection when we send the
       * nop as a ping.
       */
      if (time_after_eq(task->last_xfer, task->last_timeout)) {
            ISCSI_DBG_EH(session, "Command making progress. Asking "
                       "scsi-ml for more time to complete. "
                       "Last data recv at %lu. Last timeout was at "
                       "%lu\n.", task->last_xfer, task->last_timeout);
            task->have_checked_conn = false;
            rc = BLK_EH_RESET_TIMER;
            goto done;
      }

      if (!conn->recv_timeout && !conn->ping_timeout)
            goto done;
      /*
       * if the ping timedout then we are in the middle of cleaning up
       * and can let the iscsi eh handle it
       */
      if (iscsi_has_ping_timed_out(conn)) {
            rc = BLK_EH_RESET_TIMER;
            goto done;
      }

      /* Assumes nop timeout is shorter than scsi cmd timeout */
      if (task->have_checked_conn)
            goto done;

      /*
       * Checking the transport already or nop from a cmd timeout still
       * running
       */
      if (conn->ping_task) {
            task->have_checked_conn = true;
            rc = BLK_EH_RESET_TIMER;
            goto done;
      }

      /* Make sure there is a transport check done */
      iscsi_send_nopout(conn, NULL);
      task->have_checked_conn = true;
      rc = BLK_EH_RESET_TIMER;

done:
      if (task)
            task->last_timeout = jiffies;
      spin_unlock(&session->lock);
      ISCSI_DBG_EH(session, "return %s\n", rc == BLK_EH_RESET_TIMER ?
                 "timer reset" : "nh");
      return rc;
}

static void iscsi_check_transport_timeouts(unsigned long data)
{
      struct iscsi_conn *conn = (struct iscsi_conn *)data;
      struct iscsi_session *session = conn->session;
      unsigned long recv_timeout, next_timeout = 0, last_recv;

      spin_lock(&session->lock);
      if (session->state != ISCSI_STATE_LOGGED_IN)
            goto done;

      recv_timeout = conn->recv_timeout;
      if (!recv_timeout)
            goto done;

      recv_timeout *= HZ;
      last_recv = conn->last_recv;

      if (iscsi_has_ping_timed_out(conn)) {
            iscsi_conn_printk(KERN_ERR, conn, "ping timeout of %d secs "
                          "expired, recv timeout %d, last rx %lu, "
                          "last ping %lu, now %lu\n",
                          conn->ping_timeout, conn->recv_timeout,
                          last_recv, conn->last_ping, jiffies);
            spin_unlock(&session->lock);
            iscsi_conn_failure(conn, ISCSI_ERR_CONN_FAILED);
            return;
      }

      if (time_before_eq(last_recv + recv_timeout, jiffies)) {
            /* send a ping to try to provoke some traffic */
            ISCSI_DBG_CONN(conn, "Sending nopout as ping\n");
            iscsi_send_nopout(conn, NULL);
            next_timeout = conn->last_ping + (conn->ping_timeout * HZ);
      } else
            next_timeout = last_recv + recv_timeout;

      ISCSI_DBG_CONN(conn, "Setting next tmo %lu\n", next_timeout);
      mod_timer(&conn->transport_timer, next_timeout);
done:
      spin_unlock(&session->lock);
}

static void iscsi_prep_abort_task_pdu(struct iscsi_task *task,
                              struct iscsi_tm *hdr)
{
      memset(hdr, 0, sizeof(*hdr));
      hdr->opcode = ISCSI_OP_SCSI_TMFUNC | ISCSI_OP_IMMEDIATE;
      hdr->flags = ISCSI_TM_FUNC_ABORT_TASK & ISCSI_FLAG_TM_FUNC_MASK;
      hdr->flags |= ISCSI_FLAG_CMD_FINAL;
      memcpy(hdr->lun, task->lun, sizeof(hdr->lun));
      hdr->rtt = task->hdr_itt;
      hdr->refcmdsn = task->cmdsn;
}

int iscsi_eh_abort(struct scsi_cmnd *sc)
{
      struct iscsi_cls_session *cls_session;
      struct iscsi_session *session;
      struct iscsi_conn *conn;
      struct iscsi_task *task;
      struct iscsi_tm *hdr;
      int rc, age;

      cls_session = starget_to_session(scsi_target(sc->device));
      session = cls_session->dd_data;

      ISCSI_DBG_EH(session, "aborting sc %p\n", sc);

      mutex_lock(&session->eh_mutex);
      spin_lock_bh(&session->lock);
      /*
       * if session was ISCSI_STATE_IN_RECOVERY then we may not have
       * got the command.
       */
      if (!sc->SCp.ptr) {
            ISCSI_DBG_EH(session, "sc never reached iscsi layer or "
                              "it completed.\n");
            spin_unlock_bh(&session->lock);
            mutex_unlock(&session->eh_mutex);
            return SUCCESS;
      }

      /*
       * If we are not logged in or we have started a new session
       * then let the host reset code handle this
       */
      if (!session->leadconn || session->state != ISCSI_STATE_LOGGED_IN ||
          sc->SCp.phase != session->age) {
            spin_unlock_bh(&session->lock);
            mutex_unlock(&session->eh_mutex);
            ISCSI_DBG_EH(session, "failing abort due to dropped "
                          "session.\n");
            return FAILED;
      }

      conn = session->leadconn;
      conn->eh_abort_cnt++;
      age = session->age;

      task = (struct iscsi_task *)sc->SCp.ptr;
      ISCSI_DBG_EH(session, "aborting [sc %p itt 0x%x]\n",
                 sc, task->itt);

      /* task completed before time out */
      if (!task->sc) {
            ISCSI_DBG_EH(session, "sc completed while abort in progress\n");
            goto success;
      }

      if (task->state == ISCSI_TASK_PENDING) {
            fail_scsi_task(task, DID_ABORT);
            goto success;
      }

      /* only have one tmf outstanding at a time */
      if (conn->tmf_state != TMF_INITIAL)
            goto failed;
      conn->tmf_state = TMF_QUEUED;

      hdr = &conn->tmhdr;
      iscsi_prep_abort_task_pdu(task, hdr);

      if (iscsi_exec_task_mgmt_fn(conn, hdr, age, session->abort_timeout)) {
            rc = FAILED;
            goto failed;
      }

      switch (conn->tmf_state) {
      case TMF_SUCCESS:
            spin_unlock_bh(&session->lock);
            /*
             * stop tx side incase the target had sent a abort rsp but
             * the initiator was still writing out data.
             */
            iscsi_suspend_tx(conn);
            /*
             * we do not stop the recv side because targets have been
             * good and have never sent us a successful tmf response
             * then sent more data for the cmd.
             */
            spin_lock_bh(&session->lock);
            fail_scsi_task(task, DID_ABORT);
            conn->tmf_state = TMF_INITIAL;
            spin_unlock_bh(&session->lock);
            iscsi_start_tx(conn);
            goto success_unlocked;
      case TMF_TIMEDOUT:
            spin_unlock_bh(&session->lock);
            iscsi_conn_failure(conn, ISCSI_ERR_CONN_FAILED);
            goto failed_unlocked;
      case TMF_NOT_FOUND:
            if (!sc->SCp.ptr) {
                  conn->tmf_state = TMF_INITIAL;
                  /* task completed before tmf abort response */
                  ISCSI_DBG_EH(session, "sc completed while abort in "
                                    "progress\n");
                  goto success;
            }
            /* fall through */
      default:
            conn->tmf_state = TMF_INITIAL;
            goto failed;
      }

success:
      spin_unlock_bh(&session->lock);
success_unlocked:
      ISCSI_DBG_EH(session, "abort success [sc %p itt 0x%x]\n",
                 sc, task->itt);
      mutex_unlock(&session->eh_mutex);
      return SUCCESS;

failed:
      spin_unlock_bh(&session->lock);
failed_unlocked:
      ISCSI_DBG_EH(session, "abort failed [sc %p itt 0x%x]\n", sc,
                 task ? task->itt : 0);
      mutex_unlock(&session->eh_mutex);
      return FAILED;
}
EXPORT_SYMBOL_GPL(iscsi_eh_abort);

static void iscsi_prep_lun_reset_pdu(struct scsi_cmnd *sc, struct iscsi_tm *hdr)
{
      memset(hdr, 0, sizeof(*hdr));
      hdr->opcode = ISCSI_OP_SCSI_TMFUNC | ISCSI_OP_IMMEDIATE;
      hdr->flags = ISCSI_TM_FUNC_LOGICAL_UNIT_RESET & ISCSI_FLAG_TM_FUNC_MASK;
      hdr->flags |= ISCSI_FLAG_CMD_FINAL;
      int_to_scsilun(sc->device->lun, (struct scsi_lun *)hdr->lun);
      hdr->rtt = RESERVED_ITT;
}

int iscsi_eh_device_reset(struct scsi_cmnd *sc)
{
      struct iscsi_cls_session *cls_session;
      struct iscsi_session *session;
      struct iscsi_conn *conn;
      struct iscsi_tm *hdr;
      int rc = FAILED;

      cls_session = starget_to_session(scsi_target(sc->device));
      session = cls_session->dd_data;

      ISCSI_DBG_EH(session, "LU Reset [sc %p lun %u]\n", sc, sc->device->lun);

      mutex_lock(&session->eh_mutex);
      spin_lock_bh(&session->lock);
      /*
       * Just check if we are not logged in. We cannot check for
       * the phase because the reset could come from a ioctl.
       */
      if (!session->leadconn || session->state != ISCSI_STATE_LOGGED_IN)
            goto unlock;
      conn = session->leadconn;

      /* only have one tmf outstanding at a time */
      if (conn->tmf_state != TMF_INITIAL)
            goto unlock;
      conn->tmf_state = TMF_QUEUED;

      hdr = &conn->tmhdr;
      iscsi_prep_lun_reset_pdu(sc, hdr);

      if (iscsi_exec_task_mgmt_fn(conn, hdr, session->age,
                            session->lu_reset_timeout)) {
            rc = FAILED;
            goto unlock;
      }

      switch (conn->tmf_state) {
      case TMF_SUCCESS:
            break;
      case TMF_TIMEDOUT:
            spin_unlock_bh(&session->lock);
            iscsi_conn_failure(conn, ISCSI_ERR_CONN_FAILED);
            goto done;
      default:
            conn->tmf_state = TMF_INITIAL;
            goto unlock;
      }

      rc = SUCCESS;
      spin_unlock_bh(&session->lock);

      iscsi_suspend_tx(conn);

      spin_lock_bh(&session->lock);
      fail_scsi_tasks(conn, sc->device->lun, DID_ERROR);
      conn->tmf_state = TMF_INITIAL;
      spin_unlock_bh(&session->lock);

      iscsi_start_tx(conn);
      goto done;

unlock:
      spin_unlock_bh(&session->lock);
done:
      ISCSI_DBG_EH(session, "dev reset result = %s\n",
                 rc == SUCCESS ? "SUCCESS" : "FAILED");
      mutex_unlock(&session->eh_mutex);
      return rc;
}
EXPORT_SYMBOL_GPL(iscsi_eh_device_reset);

/*
 * Pre-allocate a pool of @max items of @item_size. By default, the pool
 * should be accessed via kfifo_{get,put} on q->queue.
 * Optionally, the caller can obtain the array of object pointers
 * by passing in a non-NULL @items pointer
 */
int
iscsi_pool_init(struct iscsi_pool *q, int max, void ***items, int item_size)
{
      int i, num_arrays = 1;

      memset(q, 0, sizeof(*q));

      q->max = max;

      /* If the user passed an items pointer, he wants a copy of
       * the array. */
      if (items)
            num_arrays++;
      q->pool = kzalloc(num_arrays * max * sizeof(void*), GFP_KERNEL);
      if (q->pool == NULL)
            return -ENOMEM;

      q->queue = kfifo_init((void*)q->pool, max * sizeof(void*),
                        GFP_KERNEL, NULL);
      if (IS_ERR(q->queue)) {
            q->queue = NULL;
            goto enomem;
      }

      for (i = 0; i < max; i++) {
            q->pool[i] = kzalloc(item_size, GFP_KERNEL);
            if (q->pool[i] == NULL) {
                  q->max = i;
                  goto enomem;
            }
            __kfifo_put(q->queue, (void*)&q->pool[i], sizeof(void*));
      }

      if (items) {
            *items = q->pool + max;
            memcpy(*items, q->pool, max * sizeof(void *));
      }

      return 0;

enomem:
      iscsi_pool_free(q);
      return -ENOMEM;
}
EXPORT_SYMBOL_GPL(iscsi_pool_init);

void iscsi_pool_free(struct iscsi_pool *q)
{
      int i;

      for (i = 0; i < q->max; i++)
            kfree(q->pool[i]);
      kfree(q->pool);
      kfree(q->queue);
}
EXPORT_SYMBOL_GPL(iscsi_pool_free);

/**
 * iscsi_host_add - add host to system
 * @shost: scsi host
 * @pdev: parent device
 *
 * This should be called by partial offload and software iscsi drivers
 * to add a host to the system.
 */
int iscsi_host_add(struct Scsi_Host *shost, struct device *pdev)
{
      if (!shost->can_queue)
            shost->can_queue = ISCSI_DEF_XMIT_CMDS_MAX;

      if (!shost->cmd_per_lun)
            shost->cmd_per_lun = ISCSI_DEF_CMD_PER_LUN;

      if (!shost->transportt->eh_timed_out)
            shost->transportt->eh_timed_out = iscsi_eh_cmd_timed_out;
      return scsi_add_host(shost, pdev);
}
EXPORT_SYMBOL_GPL(iscsi_host_add);

/**
 * iscsi_host_alloc - allocate a host and driver data
 * @sht: scsi host template
 * @dd_data_size: driver host data size
 * @xmit_can_sleep: bool indicating if LLD will queue IO from a work queue
 *
 * This should be called by partial offload and software iscsi drivers.
 * To access the driver specific memory use the iscsi_host_priv() macro.
 */
struct Scsi_Host *iscsi_host_alloc(struct scsi_host_template *sht,
                           int dd_data_size, bool xmit_can_sleep)
{
      struct Scsi_Host *shost;
      struct iscsi_host *ihost;

      shost = scsi_host_alloc(sht, sizeof(struct iscsi_host) + dd_data_size);
      if (!shost)
            return NULL;
      ihost = shost_priv(shost);

      if (xmit_can_sleep) {
            snprintf(ihost->workq_name, sizeof(ihost->workq_name),
                  "iscsi_q_%d", shost->host_no);
            ihost->workq = create_singlethread_workqueue(ihost->workq_name);
            if (!ihost->workq)
                  goto free_host;
      }

      spin_lock_init(&ihost->lock);
      ihost->state = ISCSI_HOST_SETUP;
      ihost->num_sessions = 0;
      init_waitqueue_head(&ihost->session_removal_wq);
      return shost;

free_host:
      scsi_host_put(shost);
      return NULL;
}
EXPORT_SYMBOL_GPL(iscsi_host_alloc);

static void iscsi_notify_host_removed(struct iscsi_cls_session *cls_session)
{
      iscsi_session_failure(cls_session->dd_data, ISCSI_ERR_INVALID_HOST);
}

/**
 * iscsi_host_remove - remove host and sessions
 * @shost: scsi host
 *
 * If there are any sessions left, this will initiate the removal and wait
 * for the completion.
 */
void iscsi_host_remove(struct Scsi_Host *shost)
{
      struct iscsi_host *ihost = shost_priv(shost);
      unsigned long flags;

      spin_lock_irqsave(&ihost->lock, flags);
      ihost->state = ISCSI_HOST_REMOVED;
      spin_unlock_irqrestore(&ihost->lock, flags);

      iscsi_host_for_each_session(shost, iscsi_notify_host_removed);
      wait_event_interruptible(ihost->session_removal_wq,
                         ihost->num_sessions == 0);
      if (signal_pending(current))
            flush_signals(current);

      scsi_remove_host(shost);
      if (ihost->workq)
            destroy_workqueue(ihost->workq);
}
EXPORT_SYMBOL_GPL(iscsi_host_remove);

void iscsi_host_free(struct Scsi_Host *shost)
{
      struct iscsi_host *ihost = shost_priv(shost);

      kfree(ihost->netdev);
      kfree(ihost->hwaddress);
      kfree(ihost->initiatorname);
      scsi_host_put(shost);
}
EXPORT_SYMBOL_GPL(iscsi_host_free);

static void iscsi_host_dec_session_cnt(struct Scsi_Host *shost)
{
      struct iscsi_host *ihost = shost_priv(shost);
      unsigned long flags;

      shost = scsi_host_get(shost);
      if (!shost) {
            printk(KERN_ERR "Invalid state. Cannot notify host removal "
                  "of session teardown event because host already "
                  "removed.\n");
            return;
      }

      spin_lock_irqsave(&ihost->lock, flags);
      ihost->num_sessions--;
      if (ihost->num_sessions == 0)
            wake_up(&ihost->session_removal_wq);
      spin_unlock_irqrestore(&ihost->lock, flags);
      scsi_host_put(shost);
}

/**
 * iscsi_session_setup - create iscsi cls session and host and session
 * @iscsit: iscsi transport template
 * @shost: scsi host
 * @cmds_max: session can queue
 * @cmd_task_size: LLD task private data size
 * @initial_cmdsn: initial CmdSN
 *
 * This can be used by software iscsi_transports that allocate
 * a session per scsi host.
 *
 * Callers should set cmds_max to the largest total numer (mgmt + scsi) of
 * tasks they support. The iscsi layer reserves ISCSI_MGMT_CMDS_MAX tasks
 * for nop handling and login/logout requests.
 */
struct iscsi_cls_session *
iscsi_session_setup(struct iscsi_transport *iscsit, struct Scsi_Host *shost,
                uint16_t cmds_max, int cmd_task_size,
                uint32_t initial_cmdsn, unsigned int id)
{
      struct iscsi_host *ihost = shost_priv(shost);
      struct iscsi_session *session;
      struct iscsi_cls_session *cls_session;
      int cmd_i, scsi_cmds, total_cmds = cmds_max;
      unsigned long flags;

      spin_lock_irqsave(&ihost->lock, flags);
      if (ihost->state == ISCSI_HOST_REMOVED) {
            spin_unlock_irqrestore(&ihost->lock, flags);
            return NULL;
      }
      ihost->num_sessions++;
      spin_unlock_irqrestore(&ihost->lock, flags);

      if (!total_cmds)
            total_cmds = ISCSI_DEF_XMIT_CMDS_MAX;
      /*
       * The iscsi layer needs some tasks for nop handling and tmfs,
       * so the cmds_max must at least be greater than ISCSI_MGMT_CMDS_MAX
       * + 1 command for scsi IO.
       */
      if (total_cmds < ISCSI_TOTAL_CMDS_MIN) {
            printk(KERN_ERR "iscsi: invalid can_queue of %d. can_queue "
                   "must be a power of two that is at least %d.\n",
                   total_cmds, ISCSI_TOTAL_CMDS_MIN);
            goto dec_session_count;
      }

      if (total_cmds > ISCSI_TOTAL_CMDS_MAX) {
            printk(KERN_ERR "iscsi: invalid can_queue of %d. can_queue "
                   "must be a power of 2 less than or equal to %d.\n",
                   cmds_max, ISCSI_TOTAL_CMDS_MAX);
            total_cmds = ISCSI_TOTAL_CMDS_MAX;
      }

      if (!is_power_of_2(total_cmds)) {
            printk(KERN_ERR "iscsi: invalid can_queue of %d. can_queue "
                   "must be a power of 2.\n", total_cmds);
            total_cmds = rounddown_pow_of_two(total_cmds);
            if (total_cmds < ISCSI_TOTAL_CMDS_MIN)
                  return NULL;
            printk(KERN_INFO "iscsi: Rounding can_queue to %d.\n",
                   total_cmds);
      }
      scsi_cmds = total_cmds - ISCSI_MGMT_CMDS_MAX;

      cls_session = iscsi_alloc_session(shost, iscsit,
                                sizeof(struct iscsi_session));
      if (!cls_session)
            goto dec_session_count;
      session = cls_session->dd_data;
      session->cls_session = cls_session;
      session->host = shost;
      session->state = ISCSI_STATE_FREE;
      session->fast_abort = 1;
      session->lu_reset_timeout = 15;
      session->abort_timeout = 10;
      session->scsi_cmds_max = scsi_cmds;
      session->cmds_max = total_cmds;
      session->queued_cmdsn = session->cmdsn = initial_cmdsn;
      session->exp_cmdsn = initial_cmdsn + 1;
      session->max_cmdsn = initial_cmdsn + 1;
      session->max_r2t = 1;
      session->tt = iscsit;
      mutex_init(&session->eh_mutex);
      spin_lock_init(&session->lock);

      /* initialize SCSI PDU commands pool */
      if (iscsi_pool_init(&session->cmdpool, session->cmds_max,
                      (void***)&session->cmds,
                      cmd_task_size + sizeof(struct iscsi_task)))
            goto cmdpool_alloc_fail;

      /* pre-format cmds pool with ITT */
      for (cmd_i = 0; cmd_i < session->cmds_max; cmd_i++) {
            struct iscsi_task *task = session->cmds[cmd_i];

            if (cmd_task_size)
                  task->dd_data = &task[1];
            task->itt = cmd_i;
            task->state = ISCSI_TASK_FREE;
            INIT_LIST_HEAD(&task->running);
      }

      if (!try_module_get(iscsit->owner))
            goto module_get_fail;

      if (iscsi_add_session(cls_session, id))
            goto cls_session_fail;

      return cls_session;

cls_session_fail:
      module_put(iscsit->owner);
module_get_fail:
      iscsi_pool_free(&session->cmdpool);
cmdpool_alloc_fail:
      iscsi_free_session(cls_session);
dec_session_count:
      iscsi_host_dec_session_cnt(shost);
      return NULL;
}
EXPORT_SYMBOL_GPL(iscsi_session_setup);

/**
 * iscsi_session_teardown - destroy session, host, and cls_session
 * @cls_session: iscsi session
 *
 * The driver must have called iscsi_remove_session before
 * calling this.
 */
void iscsi_session_teardown(struct iscsi_cls_session *cls_session)
{
      struct iscsi_session *session = cls_session->dd_data;
      struct module *owner = cls_session->transport->owner;
      struct Scsi_Host *shost = session->host;

      iscsi_pool_free(&session->cmdpool);

      kfree(session->password);
      kfree(session->password_in);
      kfree(session->username);
      kfree(session->username_in);
      kfree(session->targetname);
      kfree(session->initiatorname);
      kfree(session->ifacename);

      iscsi_destroy_session(cls_session);
      iscsi_host_dec_session_cnt(shost);
      module_put(owner);
}
EXPORT_SYMBOL_GPL(iscsi_session_teardown);

/**
 * iscsi_conn_setup - create iscsi_cls_conn and iscsi_conn
 * @cls_session: iscsi_cls_session
 * @dd_size: private driver data size
 * @conn_idx: cid
 */
struct iscsi_cls_conn *
iscsi_conn_setup(struct iscsi_cls_session *cls_session, int dd_size,
             uint32_t conn_idx)
{
      struct iscsi_session *session = cls_session->dd_data;
      struct iscsi_conn *conn;
      struct iscsi_cls_conn *cls_conn;
      char *data;

      cls_conn = iscsi_create_conn(cls_session, sizeof(*conn) + dd_size,
                             conn_idx);
      if (!cls_conn)
            return NULL;
      conn = cls_conn->dd_data;
      memset(conn, 0, sizeof(*conn) + dd_size);

      conn->dd_data = cls_conn->dd_data + sizeof(*conn);
      conn->session = session;
      conn->cls_conn = cls_conn;
      conn->c_stage = ISCSI_CONN_INITIAL_STAGE;
      conn->id = conn_idx;
      conn->exp_statsn = 0;
      conn->tmf_state = TMF_INITIAL;

      init_timer(&conn->transport_timer);
      conn->transport_timer.data = (unsigned long)conn;
      conn->transport_timer.function = iscsi_check_transport_timeouts;

      INIT_LIST_HEAD(&conn->mgmtqueue);
      INIT_LIST_HEAD(&conn->cmdqueue);
      INIT_LIST_HEAD(&conn->requeue);
      INIT_WORK(&conn->xmitwork, iscsi_xmitworker);

      /* allocate login_task used for the login/text sequences */
      spin_lock_bh(&session->lock);
      if (!__kfifo_get(session->cmdpool.queue,
                         (void*)&conn->login_task,
                   sizeof(void*))) {
            spin_unlock_bh(&session->lock);
            goto login_task_alloc_fail;
      }
      spin_unlock_bh(&session->lock);

      data = (char *) __get_free_pages(GFP_KERNEL,
                               get_order(ISCSI_DEF_MAX_RECV_SEG_LEN));
      if (!data)
            goto login_task_data_alloc_fail;
      conn->login_task->data = conn->data = data;

      init_timer(&conn->tmf_timer);
      init_waitqueue_head(&conn->ehwait);

      return cls_conn;

login_task_data_alloc_fail:
      __kfifo_put(session->cmdpool.queue, (void*)&conn->login_task,
                sizeof(void*));
login_task_alloc_fail:
      iscsi_destroy_conn(cls_conn);
      return NULL;
}
EXPORT_SYMBOL_GPL(iscsi_conn_setup);

/**
 * iscsi_conn_teardown - teardown iscsi connection
 * cls_conn: iscsi class connection
 *
 * TODO: we may need to make this into a two step process
 * like scsi-mls remove + put host
 */
void iscsi_conn_teardown(struct iscsi_cls_conn *cls_conn)
{
      struct iscsi_conn *conn = cls_conn->dd_data;
      struct iscsi_session *session = conn->session;
      unsigned long flags;

      del_timer_sync(&conn->transport_timer);

      spin_lock_bh(&session->lock);
      conn->c_stage = ISCSI_CONN_CLEANUP_WAIT;
      if (session->leadconn == conn) {
            /*
             * leading connection? then give up on recovery.
             */
            session->state = ISCSI_STATE_TERMINATE;
            wake_up(&conn->ehwait);
      }
      spin_unlock_bh(&session->lock);

      /*
       * Block until all in-progress commands for this connection
       * time out or fail.
       */
      for (;;) {
            spin_lock_irqsave(session->host->host_lock, flags);
            if (!session->host->host_busy) { /* OK for ERL == 0 */
                  spin_unlock_irqrestore(session->host->host_lock, flags);
                  break;
            }
            spin_unlock_irqrestore(session->host->host_lock, flags);
            msleep_interruptible(500);
            iscsi_conn_printk(KERN_INFO, conn, "iscsi conn_destroy(): "
                          "host_busy %d host_failed %d\n",
                          session->host->host_busy,
                          session->host->host_failed);
            /*
             * force eh_abort() to unblock
             */
            wake_up(&conn->ehwait);
      }

      /* flush queued up work because we free the connection below */
      iscsi_suspend_tx(conn);

      spin_lock_bh(&session->lock);
      free_pages((unsigned long) conn->data,
               get_order(ISCSI_DEF_MAX_RECV_SEG_LEN));
      kfree(conn->persistent_address);
      __kfifo_put(session->cmdpool.queue, (void*)&conn->login_task,
                sizeof(void*));
      if (session->leadconn == conn)
            session->leadconn = NULL;
      spin_unlock_bh(&session->lock);

      iscsi_destroy_conn(cls_conn);
}
EXPORT_SYMBOL_GPL(iscsi_conn_teardown);

int iscsi_conn_start(struct iscsi_cls_conn *cls_conn)
{
      struct iscsi_conn *conn = cls_conn->dd_data;
      struct iscsi_session *session = conn->session;

      if (!session) {
            iscsi_conn_printk(KERN_ERR, conn,
                          "can't start unbound connection\n");
            return -EPERM;
      }

      if ((session->imm_data_en || !session->initial_r2t_en) &&
           session->first_burst > session->max_burst) {
            iscsi_conn_printk(KERN_INFO, conn, "invalid burst lengths: "
                          "first_burst %d max_burst %d\n",
                          session->first_burst, session->max_burst);
            return -EINVAL;
      }

      if (conn->ping_timeout && !conn->recv_timeout) {
            iscsi_conn_printk(KERN_ERR, conn, "invalid recv timeout of "
                          "zero. Using 5 seconds\n.");
            conn->recv_timeout = 5;
      }

      if (conn->recv_timeout && !conn->ping_timeout) {
            iscsi_conn_printk(KERN_ERR, conn, "invalid ping timeout of "
                          "zero. Using 5 seconds.\n");
            conn->ping_timeout = 5;
      }

      spin_lock_bh(&session->lock);
      conn->c_stage = ISCSI_CONN_STARTED;
      session->state = ISCSI_STATE_LOGGED_IN;
      session->queued_cmdsn = session->cmdsn;

      conn->last_recv = jiffies;
      conn->last_ping = jiffies;
      if (conn->recv_timeout && conn->ping_timeout)
            mod_timer(&conn->transport_timer,
                    jiffies + (conn->recv_timeout * HZ));

      switch(conn->stop_stage) {
      case STOP_CONN_RECOVER:
            /*
             * unblock eh_abort() if it is blocked. re-try all
             * commands after successful recovery
             */
            conn->stop_stage = 0;
            conn->tmf_state = TMF_INITIAL;
            session->age++;
            if (session->age == 16)
                  session->age = 0;
            break;
      case STOP_CONN_TERM:
            conn->stop_stage = 0;
            break;
      default:
            break;
      }
      spin_unlock_bh(&session->lock);

      iscsi_unblock_session(session->cls_session);
      wake_up(&conn->ehwait);
      return 0;
}
EXPORT_SYMBOL_GPL(iscsi_conn_start);

static void
fail_mgmt_tasks(struct iscsi_session *session, struct iscsi_conn *conn)
{
      struct iscsi_task *task;
      int i, state;

      for (i = 0; i < conn->session->cmds_max; i++) {
            task = conn->session->cmds[i];
            if (task->sc)
                  continue;

            if (task->state == ISCSI_TASK_FREE)
                  continue;

            ISCSI_DBG_SESSION(conn->session,
                          "failing mgmt itt 0x%x state %d\n",
                          task->itt, task->state);
            state = ISCSI_TASK_ABRT_SESS_RECOV;
            if (task->state == ISCSI_TASK_PENDING)
                  state = ISCSI_TASK_COMPLETED;
            iscsi_complete_task(task, state);

      }
}

static void iscsi_start_session_recovery(struct iscsi_session *session,
                               struct iscsi_conn *conn, int flag)
{
      int old_stop_stage;

      mutex_lock(&session->eh_mutex);
      spin_lock_bh(&session->lock);
      if (conn->stop_stage == STOP_CONN_TERM) {
            spin_unlock_bh(&session->lock);
            mutex_unlock(&session->eh_mutex);
            return;
      }

      /*
       * When this is called for the in_login state, we only want to clean
       * up the login task and connection. We do not need to block and set
       * the recovery state again
       */
      if (flag == STOP_CONN_TERM)
            session->state = ISCSI_STATE_TERMINATE;
      else if (conn->stop_stage != STOP_CONN_RECOVER)
            session->state = ISCSI_STATE_IN_RECOVERY;
      spin_unlock_bh(&session->lock);

      del_timer_sync(&conn->transport_timer);
      iscsi_suspend_tx(conn);

      spin_lock_bh(&session->lock);
      old_stop_stage = conn->stop_stage;
      conn->stop_stage = flag;
      conn->c_stage = ISCSI_CONN_STOPPED;
      spin_unlock_bh(&session->lock);

      /*
       * for connection level recovery we should not calculate
       * header digest. conn->hdr_size used for optimization
       * in hdr_extract() and will be re-negotiated at
       * set_param() time.
       */
      if (flag == STOP_CONN_RECOVER) {
            conn->hdrdgst_en = 0;
            conn->datadgst_en = 0;
            if (session->state == ISCSI_STATE_IN_RECOVERY &&
                old_stop_stage != STOP_CONN_RECOVER) {
                  ISCSI_DBG_SESSION(session, "blocking session\n");
                  iscsi_block_session(session->cls_session);
            }
      }

      /*
       * flush queues.
       */
      spin_lock_bh(&session->lock);
      fail_scsi_tasks(conn, -1, DID_TRANSPORT_DISRUPTED);
      fail_mgmt_tasks(session, conn);
      spin_unlock_bh(&session->lock);
      mutex_unlock(&session->eh_mutex);
}

void iscsi_conn_stop(struct iscsi_cls_conn *cls_conn, int flag)
{
      struct iscsi_conn *conn = cls_conn->dd_data;
      struct iscsi_session *session = conn->session;

      switch (flag) {
      case STOP_CONN_RECOVER:
      case STOP_CONN_TERM:
            iscsi_start_session_recovery(session, conn, flag);
            break;
      default:
            iscsi_conn_printk(KERN_ERR, conn,
                          "invalid stop flag %d\n", flag);
      }
}
EXPORT_SYMBOL_GPL(iscsi_conn_stop);

int iscsi_conn_bind(struct iscsi_cls_session *cls_session,
                struct iscsi_cls_conn *cls_conn, int is_leading)
{
      struct iscsi_session *session = cls_session->dd_data;
      struct iscsi_conn *conn = cls_conn->dd_data;

      spin_lock_bh(&session->lock);
      if (is_leading)
            session->leadconn = conn;
      spin_unlock_bh(&session->lock);

      /*
       * Unblock xmitworker(), Login Phase will pass through.
       */
      clear_bit(ISCSI_SUSPEND_BIT, &conn->suspend_rx);
      clear_bit(ISCSI_SUSPEND_BIT, &conn->suspend_tx);
      return 0;
}
EXPORT_SYMBOL_GPL(iscsi_conn_bind);

static int iscsi_switch_str_param(char **param, char *new_val_buf)
{
      char *new_val;

      if (*param) {
            if (!strcmp(*param, new_val_buf))
                  return 0;
      }

      new_val = kstrdup(new_val_buf, GFP_NOIO);
      if (!new_val)
            return -ENOMEM;

      kfree(*param);
      *param = new_val;
      return 0;
}

int iscsi_set_param(struct iscsi_cls_conn *cls_conn,
                enum iscsi_param param, char *buf, int buflen)
{
      struct iscsi_conn *conn = cls_conn->dd_data;
      struct iscsi_session *session = conn->session;
      uint32_t value;

      switch(param) {
      case ISCSI_PARAM_FAST_ABORT:
            sscanf(buf, "%d", &session->fast_abort);
            break;
      case ISCSI_PARAM_ABORT_TMO:
            sscanf(buf, "%d", &session->abort_timeout);
            break;
      case ISCSI_PARAM_LU_RESET_TMO:
            sscanf(buf, "%d", &session->lu_reset_timeout);
            break;
      case ISCSI_PARAM_PING_TMO:
            sscanf(buf, "%d", &conn->ping_timeout);
            break;
      case ISCSI_PARAM_RECV_TMO:
            sscanf(buf, "%d", &conn->recv_timeout);
            break;
      case ISCSI_PARAM_MAX_RECV_DLENGTH:
            sscanf(buf, "%d", &conn->max_recv_dlength);
            break;
      case ISCSI_PARAM_MAX_XMIT_DLENGTH:
            sscanf(buf, "%d", &conn->max_xmit_dlength);
            break;
      case ISCSI_PARAM_HDRDGST_EN:
            sscanf(buf, "%d", &conn->hdrdgst_en);
            break;
      case ISCSI_PARAM_DATADGST_EN:
            sscanf(buf, "%d", &conn->datadgst_en);
            break;
      case ISCSI_PARAM_INITIAL_R2T_EN:
            sscanf(buf, "%d", &session->initial_r2t_en);
            break;
      case ISCSI_PARAM_MAX_R2T:
            sscanf(buf, "%d", &session->max_r2t);
            break;
      case ISCSI_PARAM_IMM_DATA_EN:
            sscanf(buf, "%d", &session->imm_data_en);
            break;
      case ISCSI_PARAM_FIRST_BURST:
            sscanf(buf, "%d", &session->first_burst);
            break;
      case ISCSI_PARAM_MAX_BURST:
            sscanf(buf, "%d", &session->max_burst);
            break;
      case ISCSI_PARAM_PDU_INORDER_EN:
            sscanf(buf, "%d", &session->pdu_inorder_en);
            break;
      case ISCSI_PARAM_DATASEQ_INORDER_EN:
            sscanf(buf, "%d", &session->dataseq_inorder_en);
            break;
      case ISCSI_PARAM_ERL:
            sscanf(buf, "%d", &session->erl);
            break;
      case ISCSI_PARAM_IFMARKER_EN:
            sscanf(buf, "%d", &value);
            BUG_ON(value);
            break;
      case ISCSI_PARAM_OFMARKER_EN:
            sscanf(buf, "%d", &value);
            BUG_ON(value);
            break;
      case ISCSI_PARAM_EXP_STATSN:
            sscanf(buf, "%u", &conn->exp_statsn);
            break;
      case ISCSI_PARAM_USERNAME:
            return iscsi_switch_str_param(&session->username, buf);
      case ISCSI_PARAM_USERNAME_IN:
            return iscsi_switch_str_param(&session->username_in, buf);
      case ISCSI_PARAM_PASSWORD:
            return iscsi_switch_str_param(&session->password, buf);
      case ISCSI_PARAM_PASSWORD_IN:
            return iscsi_switch_str_param(&session->password_in, buf);
      case ISCSI_PARAM_TARGET_NAME:
            return iscsi_switch_str_param(&session->targetname, buf);
      case ISCSI_PARAM_TPGT:
            sscanf(buf, "%d", &session->tpgt);
            break;
      case ISCSI_PARAM_PERSISTENT_PORT:
            sscanf(buf, "%d", &conn->persistent_port);
            break;
      case ISCSI_PARAM_PERSISTENT_ADDRESS:
            return iscsi_switch_str_param(&conn->persistent_address, buf);
      case ISCSI_PARAM_IFACE_NAME:
            return iscsi_switch_str_param(&session->ifacename, buf);
      case ISCSI_PARAM_INITIATOR_NAME:
            return iscsi_switch_str_param(&session->initiatorname, buf);
      default:
            return -ENOSYS;
      }

      return 0;
}
EXPORT_SYMBOL_GPL(iscsi_set_param);

int iscsi_session_get_param(struct iscsi_cls_session *cls_session,
                      enum iscsi_param param, char *buf)
{
      struct iscsi_session *session = cls_session->dd_data;
      int len;

      switch(param) {
      case ISCSI_PARAM_FAST_ABORT:
            len = sprintf(buf, "%d\n", session->fast_abort);
            break;
      case ISCSI_PARAM_ABORT_TMO:
            len = sprintf(buf, "%d\n", session->abort_timeout);
            break;
      case ISCSI_PARAM_LU_RESET_TMO:
            len = sprintf(buf, "%d\n", session->lu_reset_timeout);
            break;
      case ISCSI_PARAM_INITIAL_R2T_EN:
            len = sprintf(buf, "%d\n", session->initial_r2t_en);
            break;
      case ISCSI_PARAM_MAX_R2T:
            len = sprintf(buf, "%hu\n", session->max_r2t);
            break;
      case ISCSI_PARAM_IMM_DATA_EN:
            len = sprintf(buf, "%d\n", session->imm_data_en);
            break;
      case ISCSI_PARAM_FIRST_BURST:
            len = sprintf(buf, "%u\n", session->first_burst);
            break;
      case ISCSI_PARAM_MAX_BURST:
            len = sprintf(buf, "%u\n", session->max_burst);
            break;
      case ISCSI_PARAM_PDU_INORDER_EN:
            len = sprintf(buf, "%d\n", session->pdu_inorder_en);
            break;
      case ISCSI_PARAM_DATASEQ_INORDER_EN:
            len = sprintf(buf, "%d\n", session->dataseq_inorder_en);
            break;
      case ISCSI_PARAM_ERL:
            len = sprintf(buf, "%d\n", session->erl);
            break;
      case ISCSI_PARAM_TARGET_NAME:
            len = sprintf(buf, "%s\n", session->targetname);
            break;
      case ISCSI_PARAM_TPGT:
            len = sprintf(buf, "%d\n", session->tpgt);
            break;
      case ISCSI_PARAM_USERNAME:
            len = sprintf(buf, "%s\n", session->username);
            break;
      case ISCSI_PARAM_USERNAME_IN:
            len = sprintf(buf, "%s\n", session->username_in);
            break;
      case ISCSI_PARAM_PASSWORD:
            len = sprintf(buf, "%s\n", session->password);
            break;
      case ISCSI_PARAM_PASSWORD_IN:
            len = sprintf(buf, "%s\n", session->password_in);
            break;
      case ISCSI_PARAM_IFACE_NAME:
            len = sprintf(buf, "%s\n", session->ifacename);
            break;
      case ISCSI_PARAM_INITIATOR_NAME:
            len = sprintf(buf, "%s\n", session->initiatorname);
            break;
      default:
            return -ENOSYS;
      }

      return len;
}
EXPORT_SYMBOL_GPL(iscsi_session_get_param);

int iscsi_conn_get_param(struct iscsi_cls_conn *cls_conn,
                   enum iscsi_param param, char *buf)
{
      struct iscsi_conn *conn = cls_conn->dd_data;
      int len;

      switch(param) {
      case ISCSI_PARAM_PING_TMO:
            len = sprintf(buf, "%u\n", conn->ping_timeout);
            break;
      case ISCSI_PARAM_RECV_TMO:
            len = sprintf(buf, "%u\n", conn->recv_timeout);
            break;
      case ISCSI_PARAM_MAX_RECV_DLENGTH:
            len = sprintf(buf, "%u\n", conn->max_recv_dlength);
            break;
      case ISCSI_PARAM_MAX_XMIT_DLENGTH:
            len = sprintf(buf, "%u\n", conn->max_xmit_dlength);
            break;
      case ISCSI_PARAM_HDRDGST_EN:
            len = sprintf(buf, "%d\n", conn->hdrdgst_en);
            break;
      case ISCSI_PARAM_DATADGST_EN:
            len = sprintf(buf, "%d\n", conn->datadgst_en);
            break;
      case ISCSI_PARAM_IFMARKER_EN:
            len = sprintf(buf, "%d\n", conn->ifmarker_en);
            break;
      case ISCSI_PARAM_OFMARKER_EN:
            len = sprintf(buf, "%d\n", conn->ofmarker_en);
            break;
      case ISCSI_PARAM_EXP_STATSN:
            len = sprintf(buf, "%u\n", conn->exp_statsn);
            break;
      case ISCSI_PARAM_PERSISTENT_PORT:
            len = sprintf(buf, "%d\n", conn->persistent_port);
            break;
      case ISCSI_PARAM_PERSISTENT_ADDRESS:
            len = sprintf(buf, "%s\n", conn->persistent_address);
            break;
      default:
            return -ENOSYS;
      }

      return len;
}
EXPORT_SYMBOL_GPL(iscsi_conn_get_param);

int iscsi_host_get_param(struct Scsi_Host *shost, enum iscsi_host_param param,
                   char *buf)
{
      struct iscsi_host *ihost = shost_priv(shost);
      int len;

      switch (param) {
      case ISCSI_HOST_PARAM_NETDEV_NAME:
            len = sprintf(buf, "%s\n", ihost->netdev);
            break;
      case ISCSI_HOST_PARAM_HWADDRESS:
            len = sprintf(buf, "%s\n", ihost->hwaddress);
            break;
      case ISCSI_HOST_PARAM_INITIATOR_NAME:
            len = sprintf(buf, "%s\n", ihost->initiatorname);
            break;
      case ISCSI_HOST_PARAM_IPADDRESS:
            len = sprintf(buf, "%s\n", ihost->local_address);
            break;
      default:
            return -ENOSYS;
      }

      return len;
}
EXPORT_SYMBOL_GPL(iscsi_host_get_param);

int iscsi_host_set_param(struct Scsi_Host *shost, enum iscsi_host_param param,
                   char *buf, int buflen)
{
      struct iscsi_host *ihost = shost_priv(shost);

      switch (param) {
      case ISCSI_HOST_PARAM_NETDEV_NAME:
            return iscsi_switch_str_param(&ihost->netdev, buf);
      case ISCSI_HOST_PARAM_HWADDRESS:
            return iscsi_switch_str_param(&ihost->hwaddress, buf);
      case ISCSI_HOST_PARAM_INITIATOR_NAME:
            return iscsi_switch_str_param(&ihost->initiatorname, buf);
      default:
            return -ENOSYS;
      }

      return 0;
}
EXPORT_SYMBOL_GPL(iscsi_host_set_param);

MODULE_AUTHOR("Mike Christie");
MODULE_DESCRIPTION("iSCSI library functions");
MODULE_LICENSE("GPL");

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