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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 <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>

struct iscsi_session *
class_to_transport_session(struct iscsi_cls_session *cls_session)
{
      struct Scsi_Host *shost = iscsi_session_to_shost(cls_session);
      return iscsi_hostdata(shost->hostdata);
}
EXPORT_SYMBOL_GPL(class_to_transport_session);

/* 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)));
}

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->xmitqueue) ||
                __kfifo_len(session->leadconn->mgmtqueue))
                  scsi_queue_work(session->host,
                              &session->leadconn->xmitwork);
      }
}
EXPORT_SYMBOL_GPL(iscsi_update_cmdsn);

void iscsi_prep_unsolicit_data_pdu(struct iscsi_cmd_task *ctask,
                           struct iscsi_data *hdr)
{
      struct iscsi_conn *conn = ctask->conn;

      memset(hdr, 0, sizeof(struct iscsi_data));
      hdr->ttt = cpu_to_be32(ISCSI_RESERVED_TAG);
      hdr->datasn = cpu_to_be32(ctask->unsol_datasn);
      ctask->unsol_datasn++;
      hdr->opcode = ISCSI_OP_SCSI_DATA_OUT;
      memcpy(hdr->lun, ctask->hdr->lun, sizeof(hdr->lun));

      hdr->itt = ctask->hdr->itt;
      hdr->exp_statsn = cpu_to_be32(conn->exp_statsn);
      hdr->offset = cpu_to_be32(ctask->unsol_offset);

      if (ctask->unsol_count > conn->max_xmit_dlength) {
            hton24(hdr->dlength, conn->max_xmit_dlength);
            ctask->data_count = conn->max_xmit_dlength;
            ctask->unsol_offset += ctask->data_count;
            hdr->flags = 0;
      } else {
            hton24(hdr->dlength, ctask->unsol_count);
            ctask->data_count = ctask->unsol_count;
            hdr->flags = ISCSI_FLAG_CMD_FINAL;
      }
}
EXPORT_SYMBOL_GPL(iscsi_prep_unsolicit_data_pdu);

/**
 * iscsi_prep_scsi_cmd_pdu - prep iscsi scsi cmd pdu
 * @ctask: iscsi cmd 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 void iscsi_prep_scsi_cmd_pdu(struct iscsi_cmd_task *ctask)
{
      struct iscsi_conn *conn = ctask->conn;
      struct iscsi_session *session = conn->session;
      struct iscsi_cmd *hdr = ctask->hdr;
      struct scsi_cmnd *sc = ctask->sc;

        hdr->opcode = ISCSI_OP_SCSI_CMD;
        hdr->flags = ISCSI_ATTR_SIMPLE;
        int_to_scsilun(sc->device->lun, (struct scsi_lun *)hdr->lun);
        hdr->itt = build_itt(ctask->itt, conn->id, session->age);
        hdr->data_length = cpu_to_be32(scsi_bufflen(sc));
        hdr->cmdsn = cpu_to_be32(session->cmdsn);
        session->cmdsn++;
        hdr->exp_statsn = cpu_to_be32(conn->exp_statsn);
        memcpy(hdr->cdb, sc->cmnd, sc->cmd_len);
      if (sc->cmd_len < MAX_COMMAND_SIZE)
            memset(&hdr->cdb[sc->cmd_len], 0,
                  MAX_COMMAND_SIZE - sc->cmd_len);

      ctask->data_count = 0;
      ctask->imm_count = 0;
      if (sc->sc_data_direction == DMA_TO_DEVICE) {
            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_count    bytes to be sent via R2T ack's
             *
             *      pad_count       bytes to be sent as zero-padding
             */
            ctask->unsol_count = 0;
            ctask->unsol_offset = 0;
            ctask->unsol_datasn = 0;

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

            if (!session->initial_r2t_en) {
                  ctask->unsol_count = min((session->first_burst),
                        (scsi_bufflen(sc))) - ctask->imm_count;
                  ctask->unsol_offset = ctask->imm_count;
            }

            if (!ctask->unsol_count)
                  /* No unsolicit Data-Out's */
                  ctask->hdr->flags |= ISCSI_FLAG_CMD_FINAL;
      } else {
            hdr->flags |= ISCSI_FLAG_CMD_FINAL;
            zero_data(hdr->dlength);

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

      conn->scsicmd_pdus_cnt++;

        debug_scsi("iscsi prep [%s cid %d sc %p cdb 0x%x itt 0x%x len %d "
            "cmdsn %d win %d]\n",
                sc->sc_data_direction == DMA_TO_DEVICE ? "write" : "read",
            conn->id, sc, sc->cmnd[0], ctask->itt, scsi_bufflen(sc),
                session->cmdsn, session->max_cmdsn - session->exp_cmdsn + 1);
}

/**
 * iscsi_complete_command - return command back to scsi-ml
 * @ctask: iscsi cmd task
 *
 * Must be called with session lock.
 * This function returns the scsi command to scsi-ml and returns
 * the cmd task to the pool of available cmd tasks.
 */
static void iscsi_complete_command(struct iscsi_cmd_task *ctask)
{
      struct iscsi_session *session = ctask->conn->session;
      struct scsi_cmnd *sc = ctask->sc;

      ctask->state = ISCSI_TASK_COMPLETED;
      ctask->sc = NULL;
      /* SCSI eh reuses commands to verify us */
      sc->SCp.ptr = NULL;
      list_del_init(&ctask->running);
      __kfifo_put(session->cmdpool.queue, (void*)&ctask, sizeof(void*));
      sc->scsi_done(sc);
}

static void __iscsi_get_ctask(struct iscsi_cmd_task *ctask)
{
      atomic_inc(&ctask->refcount);
}

static void __iscsi_put_ctask(struct iscsi_cmd_task *ctask)
{
      if (atomic_dec_and_test(&ctask->refcount))
            iscsi_complete_command(ctask);
}

/**
 * iscsi_cmd_rsp - SCSI Command Response processing
 * @conn: iscsi connection
 * @hdr: iscsi header
 * @ctask: 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_cmd_task *ctask, char *data,
                         int datalen)
{
      struct iscsi_cmd_rsp *rhdr = (struct iscsi_cmd_rsp *)hdr;
      struct iscsi_session *session = conn->session;
      struct scsi_cmnd *sc = ctask->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:
                  printk(KERN_ERR "iscsi: Got CHECK_CONDITION but "
                         "invalid data buffer size of %d\n", datalen);
                  sc->result = DID_BAD_TARGET << 16;
                  goto out;
            }

            senselen = be16_to_cpu(get_unaligned((__be16 *) data));
            if (datalen < senselen)
                  goto invalid_datalen;

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

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

            if (res_count > 0 && res_count <= scsi_bufflen(sc))
                  scsi_set_resid(sc, res_count);
            else
                  sc->result = (DID_BAD_TARGET << 16) | rhdr->cmd_status;
      } else if (rhdr->flags & ISCSI_FLAG_CMD_BIDI_UNDERFLOW)
            sc->result = (DID_BAD_TARGET << 16) | rhdr->cmd_status;
      else if (rhdr->flags & ISCSI_FLAG_CMD_OVERFLOW)
            scsi_set_resid(sc, be32_to_cpu(rhdr->residual_count));

out:
      debug_scsi("done [sc %lx res %d itt 0x%x]\n",
               (long)sc, sc->result, ctask->itt);
      conn->scsirsp_pdus_cnt++;

      __iscsi_put_ctask(ctask);
}

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->tmabort_state != TMABORT_INITIAL)
            return;

      if (tmf->response == ISCSI_TMF_RSP_COMPLETE)
            conn->tmabort_state = TMABORT_SUCCESS;
      else if (tmf->response == ISCSI_TMF_RSP_NO_TASK)
            conn->tmabort_state = TMABORT_NOT_FOUND;
      else
            conn->tmabort_state = TMABORT_FAILED;
      wake_up(&conn->ehwait);
}

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;
      uint32_t itt;

      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));
                  itt = get_itt(rejected_pdu.itt);
                  printk(KERN_ERR "itt 0x%x had pdu (op 0x%x) rejected "
                        "due to DataDigest error.\n", itt,
                        rejected_pdu.opcode);
            }
      }
      return 0;
}

/**
 * __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_cmd_task *ctask;
      struct iscsi_mgmt_task *mtask;
      uint32_t itt;

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

      if (itt < session->cmds_max) {
            ctask = session->cmds[itt];

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

            switch(opcode) {
            case ISCSI_OP_SCSI_CMD_RSP:
                  BUG_ON((void*)ctask != ctask->sc->SCp.ptr);
                  iscsi_scsi_cmd_rsp(conn, hdr, ctask, data,
                                 datalen);
                  break;
            case ISCSI_OP_SCSI_DATA_IN:
                  BUG_ON((void*)ctask != ctask->sc->SCp.ptr);
                  if (hdr->flags & ISCSI_FLAG_DATA_STATUS) {
                        conn->scsirsp_pdus_cnt++;
                        __iscsi_put_ctask(ctask);
                  }
                  break;
            case ISCSI_OP_R2T:
                  /* LLD handles this for now */
                  break;
            default:
                  rc = ISCSI_ERR_BAD_OPCODE;
                  break;
            }
      } else if (itt >= ISCSI_MGMT_ITT_OFFSET &&
               itt < ISCSI_MGMT_ITT_OFFSET + session->mgmtpool_max) {
            mtask = session->mgmt_cmds[itt - ISCSI_MGMT_ITT_OFFSET];

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

            iscsi_update_cmdsn(session, (struct iscsi_nopin*)hdr);
            switch(opcode) {
            case ISCSI_OP_LOGOUT_RSP:
                  if (datalen) {
                        rc = ISCSI_ERR_PROTO;
                        break;
                  }
                  conn->exp_statsn = be32_to_cpu(hdr->statsn) + 1;
                  /* fall through */
            case ISCSI_OP_LOGIN_RSP:
            case ISCSI_OP_TEXT_RSP:
                  /*
                   * login related PDU's exp_statsn is handled in
                   * userspace
                   */
                  if (iscsi_recv_pdu(conn->cls_conn, hdr, data, datalen))
                        rc = ISCSI_ERR_CONN_FAILED;
                  list_del(&mtask->running);
                  if (conn->login_mtask != mtask)
                        __kfifo_put(session->mgmtpool.queue,
                                  (void*)&mtask, sizeof(void*));
                  break;
            case ISCSI_OP_SCSI_TMFUNC_RSP:
                  if (datalen) {
                        rc = ISCSI_ERR_PROTO;
                        break;
                  }

                  iscsi_tmf_rsp(conn, hdr);
                  break;
            case ISCSI_OP_NOOP_IN:
                  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 (iscsi_recv_pdu(conn->cls_conn, hdr, data, datalen))
                        rc = ISCSI_ERR_CONN_FAILED;
                  list_del(&mtask->running);
                  if (conn->login_mtask != mtask)
                        __kfifo_put(session->mgmtpool.queue,
                                  (void*)&mtask, sizeof(void*));
                  break;
            default:
                  rc = ISCSI_ERR_BAD_OPCODE;
                  break;
            }
      } else 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;

                  if (iscsi_recv_pdu(conn->cls_conn, hdr, NULL, 0))
                        rc = ISCSI_ERR_CONN_FAILED;
                  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;
            }
      } else
            rc = ISCSI_ERR_BAD_ITT;

      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);

/* verify itt (itt encoding: age+cid+itt) */
int iscsi_verify_itt(struct iscsi_conn *conn, struct iscsi_hdr *hdr,
                 uint32_t *ret_itt)
{
      struct iscsi_session *session = conn->session;
      struct iscsi_cmd_task *ctask;
      uint32_t itt;

      if (hdr->itt != RESERVED_ITT) {
            if (((__force u32)hdr->itt & ISCSI_AGE_MASK) !=
                (session->age << ISCSI_AGE_SHIFT)) {
                  printk(KERN_ERR "iscsi: received itt %x expected "
                        "session age (%x)\n", (__force u32)hdr->itt,
                        session->age & ISCSI_AGE_MASK);
                  return ISCSI_ERR_BAD_ITT;
            }

            if (((__force u32)hdr->itt & ISCSI_CID_MASK) !=
                (conn->id << ISCSI_CID_SHIFT)) {
                  printk(KERN_ERR "iscsi: received itt %x, expected "
                        "CID (%x)\n", (__force u32)hdr->itt, conn->id);
                  return ISCSI_ERR_BAD_ITT;
            }
            itt = get_itt(hdr->itt);
      } else
            itt = ~0U;

      if (itt < session->cmds_max) {
            ctask = session->cmds[itt];

            if (!ctask->sc) {
                  printk(KERN_INFO "iscsi: dropping ctask with "
                         "itt 0x%x\n", ctask->itt);
                  /* force drop */
                  return ISCSI_ERR_NO_SCSI_CMD;
            }

            if (ctask->sc->SCp.phase != session->age) {
                  printk(KERN_ERR "iscsi: ctask's session age %d, "
                        "expected %d\n", ctask->sc->SCp.phase,
                        session->age);
                  return ISCSI_ERR_SESSION_FAILED;
            }
      }

      *ret_itt = itt;
      return 0;
}
EXPORT_SYMBOL_GPL(iscsi_verify_itt);

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(conn->cls_conn, err);
}
EXPORT_SYMBOL_GPL(iscsi_conn_failure);

static void iscsi_prep_mtask(struct iscsi_conn *conn,
                       struct iscsi_mgmt_task *mtask)
{
      struct iscsi_session *session = conn->session;
      struct iscsi_hdr *hdr = mtask->hdr;
      struct iscsi_nopout *nop = (struct iscsi_nopout *)hdr;

      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) {
            hdr->itt = build_itt(mtask->itt, conn->id, session->age);
            /*
             * 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_mgmt_task)
            session->tt->init_mgmt_task(conn, mtask);

      debug_scsi("mgmtpdu [op 0x%x hdr->itt 0x%x datalen %d]\n",
               hdr->opcode, hdr->itt, mtask->data_count);
}

static int iscsi_xmit_mtask(struct iscsi_conn *conn)
{
      struct iscsi_hdr *hdr = conn->mtask->hdr;
      int rc, was_logout = 0;

      spin_unlock_bh(&conn->session->lock);
      if ((hdr->opcode & ISCSI_OPCODE_MASK) == ISCSI_OP_LOGOUT) {
            conn->session->state = ISCSI_STATE_IN_RECOVERY;
            iscsi_block_session(session_to_cls(conn->session));
            was_logout = 1;
      }
      rc = conn->session->tt->xmit_mgmt_task(conn, conn->mtask);
      spin_lock_bh(&conn->session->lock);
      if (rc)
            return rc;

      /* done with this in-progress mtask */
      conn->mtask = NULL;

      if (was_logout) {
            set_bit(ISCSI_SUSPEND_BIT, &conn->suspend_tx);
            return -ENODATA;
      }
      return 0;
}

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)) {
            debug_scsi("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_ctask(struct iscsi_conn *conn)
{
      struct iscsi_cmd_task *ctask = conn->ctask;
      int rc = 0;

      /*
       * serialize with TMF AbortTask
       */
      if (ctask->state == ISCSI_TASK_ABORTING)
            goto done;

      __iscsi_get_ctask(ctask);
      spin_unlock_bh(&conn->session->lock);
      rc = conn->session->tt->xmit_cmd_task(conn, ctask);
      spin_lock_bh(&conn->session->lock);
      __iscsi_put_ctask(ctask);

done:
      if (!rc)
            /* done with this ctask */
            conn->ctask = NULL;
      return rc;
}

/**
 * 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)) {
            debug_scsi("conn %d Tx suspended!\n", conn->id);
            spin_unlock_bh(&conn->session->lock);
            return -ENODATA;
      }

      if (conn->ctask) {
            rc = iscsi_xmit_ctask(conn);
            if (rc)
                  goto again;
      }

      if (conn->mtask) {
            rc = iscsi_xmit_mtask(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 (__kfifo_get(conn->mgmtqueue, (void*)&conn->mtask,
                     sizeof(void*))) {
            iscsi_prep_mtask(conn, conn->mtask);
            list_add_tail(&conn->mtask->running, &conn->mgmt_run_list);
            rc = iscsi_xmit_mtask(conn);
            if (rc)
                  goto again;
      }

      /* process command queue */
      while (!list_empty(&conn->xmitqueue)) {
            /*
             * iscsi tcp may readd the task to the xmitqueue to send
             * write data
             */
            conn->ctask = list_entry(conn->xmitqueue.next,
                               struct iscsi_cmd_task, running);
            switch (conn->ctask->state) {
            case ISCSI_TASK_ABORTING:
                  break;
            case ISCSI_TASK_PENDING:
                  iscsi_prep_scsi_cmd_pdu(conn->ctask);
                  conn->session->tt->init_cmd_task(conn->ctask);
                  /* fall through */
            default:
                  conn->ctask->state = ISCSI_TASK_RUNNING;
                  break;
            }
            list_move_tail(conn->xmitqueue.next, &conn->run_list);

            rc = iscsi_xmit_ctask(conn);
            if (rc)
                  goto again;
            /*
             * we could continuously get new ctask requests so
             * we need to check the mgmt queue for nops that need to
             * be sent to aviod starvation
             */
            if (__kfifo_len(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);
}

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,
};

int iscsi_queuecommand(struct scsi_cmnd *sc, void (*done)(struct scsi_cmnd *))
{
      struct Scsi_Host *host;
      int reason = 0;
      struct iscsi_session *session;
      struct iscsi_conn *conn;
      struct iscsi_cmd_task *ctask = NULL;

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

      host = sc->device->host;
      session = iscsi_hostdata(host->hostdata);

      spin_lock(&session->lock);

      /*
       * ISCSI_STATE_FAILED is a temp. state. The recovery
       * code will decide what is best to do with command queued
       * during this time
       */
      if (session->state != ISCSI_STATE_LOGGED_IN &&
          session->state != ISCSI_STATE_FAILED) {
            /*
             * 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)
             */
            if (session->state == ISCSI_STATE_IN_RECOVERY) {
                  reason = FAILURE_SESSION_IN_RECOVERY;
                  goto reject;
            }

            if (session->state == ISCSI_STATE_RECOVERY_FAILED)
                  reason = FAILURE_SESSION_RECOVERY_TIMEOUT;
            else if (session->state == ISCSI_STATE_TERMINATE)
                  reason = FAILURE_SESSION_TERMINATE;
            else
                  reason = FAILURE_SESSION_FREED;
            goto fault;
      }

      conn = session->leadconn;
      if (!conn) {
            reason = FAILURE_SESSION_FREED;
            goto fault;
      }

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

      if (!__kfifo_get(session->cmdpool.queue, (void*)&ctask,
                   sizeof(void*))) {
            reason = FAILURE_OOM;
            goto reject;
      }
      session->queued_cmdsn++;

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

      atomic_set(&ctask->refcount, 1);
      ctask->state = ISCSI_TASK_PENDING;
      ctask->mtask = NULL;
      ctask->conn = conn;
      ctask->sc = sc;
      INIT_LIST_HEAD(&ctask->running);

      list_add_tail(&ctask->running, &conn->xmitqueue);
      spin_unlock(&session->lock);

      scsi_queue_work(host, &conn->xmitwork);
      return 0;

reject:
      spin_unlock(&session->lock);
      debug_scsi("cmd 0x%x rejected (%d)\n", sc->cmnd[0], reason);
      return SCSI_MLQUEUE_HOST_BUSY;

fault:
      spin_unlock(&session->lock);
      printk(KERN_ERR "iscsi: cmd 0x%x is not queued (%d)\n",
             sc->cmnd[0], reason);
      sc->result = (DID_NO_CONNECT << 16);
      scsi_set_resid(sc, scsi_bufflen(sc));
      sc->scsi_done(sc);
      return 0;
}
EXPORT_SYMBOL_GPL(iscsi_queuecommand);

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

static struct iscsi_mgmt_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_mgmt_task *mtask;

      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 mtask can be used. Same ITT must be used.
             * Note that login_mtask is preallocated at conn_create().
             */
            mtask = conn->login_mtask;
      else {
            BUG_ON(conn->c_stage == ISCSI_CONN_INITIAL_STAGE);
            BUG_ON(conn->c_stage == ISCSI_CONN_STOPPED);

            if (!__kfifo_get(session->mgmtpool.queue,
                         (void*)&mtask, sizeof(void*)))
                  return NULL;
      }

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

      INIT_LIST_HEAD(&mtask->running);
      memcpy(mtask->hdr, hdr, sizeof(struct iscsi_hdr));
      __kfifo_put(conn->mgmtqueue, (void*)&mtask, sizeof(void*));
      return mtask;
}

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);
      scsi_queue_work(session->host, &conn->xmitwork);
      return err;
}
EXPORT_SYMBOL_GPL(iscsi_conn_send_pdu);

void iscsi_session_recovery_timedout(struct iscsi_cls_session *cls_session)
{
      struct iscsi_session *session = class_to_transport_session(cls_session);
      struct iscsi_conn *conn = session->leadconn;

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

int iscsi_eh_host_reset(struct scsi_cmnd *sc)
{
      struct Scsi_Host *host = sc->device->host;
      struct iscsi_session *session = iscsi_hostdata(host->hostdata);
      struct iscsi_conn *conn = session->leadconn;
      int fail_session = 0;

      spin_lock_bh(&session->lock);
      if (session->state == ISCSI_STATE_TERMINATE) {
failed:
            debug_scsi("failing host reset: session terminated "
                     "[CID %d age %d]\n", conn->id, session->age);
            spin_unlock_bh(&session->lock);
            return FAILED;
      }

      if (sc->SCp.phase == session->age) {
            debug_scsi("failing connection CID %d due to SCSI host reset\n",
                     conn->id);
            fail_session = 1;
      }
      spin_unlock_bh(&session->lock);

      /*
       * we drop the lock here but the leadconn cannot be destoyed while
       * we are in the scsi eh
       */
      if (fail_session)
            iscsi_conn_failure(conn, ISCSI_ERR_CONN_FAILED);

      debug_scsi("iscsi_eh_host_reset 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);

      spin_lock_bh(&session->lock);
      if (session->state == ISCSI_STATE_LOGGED_IN)
            printk(KERN_INFO "iscsi: host reset succeeded\n");
      else
            goto failed;
      spin_unlock_bh(&session->lock);

      return SUCCESS;
}
EXPORT_SYMBOL_GPL(iscsi_eh_host_reset);

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

      spin_lock(&session->lock);
      if (conn->tmabort_state == TMABORT_INITIAL) {
            conn->tmabort_state = TMABORT_TIMEDOUT;
            debug_scsi("tmabort timedout [sc %p itt 0x%x]\n",
                  ctask->sc, ctask->itt);
            /* unblock eh_abort() */
            wake_up(&conn->ehwait);
      }
      spin_unlock(&session->lock);
}

static int iscsi_exec_abort_task(struct scsi_cmnd *sc,
                         struct iscsi_cmd_task *ctask)
{
      struct iscsi_conn *conn = ctask->conn;
      struct iscsi_session *session = conn->session;
      struct iscsi_tm *hdr = &conn->tmhdr;

      /*
       * ctask timed out but session is OK requests must be serialized.
       */
      memset(hdr, 0, sizeof(struct iscsi_tm));
      hdr->opcode = ISCSI_OP_SCSI_TMFUNC | ISCSI_OP_IMMEDIATE;
      hdr->flags = ISCSI_TM_FUNC_ABORT_TASK;
      hdr->flags |= ISCSI_FLAG_CMD_FINAL;
      memcpy(hdr->lun, ctask->hdr->lun, sizeof(hdr->lun));
      hdr->rtt = ctask->hdr->itt;
      hdr->refcmdsn = ctask->hdr->cmdsn;

      ctask->mtask = __iscsi_conn_send_pdu(conn, (struct iscsi_hdr *)hdr,
                                  NULL, 0);
      if (!ctask->mtask) {
            spin_unlock_bh(&session->lock);
            iscsi_conn_failure(conn, ISCSI_ERR_CONN_FAILED);
            spin_lock_bh(&session->lock)
            debug_scsi("abort sent failure [itt 0x%x]\n", ctask->itt);
            return -EPERM;
      }
      ctask->state = ISCSI_TASK_ABORTING;

      debug_scsi("abort sent [itt 0x%x]\n", ctask->itt);

      if (conn->tmabort_state == TMABORT_INITIAL) {
            conn->tmfcmd_pdus_cnt++;
            conn->tmabort_timer.expires = 20*HZ + jiffies;
            conn->tmabort_timer.function = iscsi_tmabort_timedout;
            conn->tmabort_timer.data = (unsigned long)ctask;
            add_timer(&conn->tmabort_timer);
            debug_scsi("abort set timeout [itt 0x%x]\n", ctask->itt);
      }
      spin_unlock_bh(&session->lock);
      mutex_unlock(&session->eh_mutex);
      scsi_queue_work(session->host, &conn->xmitwork);

      /*
       * block eh thread until:
       *
       * 1) abort response
       * 2) abort timeout
       * 3) session is terminated or restarted or userspace has
       * given up on recovery
       */
      wait_event_interruptible(conn->ehwait,
                         sc->SCp.phase != session->age ||
                         session->state != ISCSI_STATE_LOGGED_IN ||
                         conn->tmabort_state != TMABORT_INITIAL);
      if (signal_pending(current))
            flush_signals(current);
      del_timer_sync(&conn->tmabort_timer);
      mutex_lock(&session->eh_mutex);
      spin_lock_bh(&session->lock);
      return 0;
}

/*
 * session lock must be held
 */
static struct iscsi_mgmt_task *
iscsi_remove_mgmt_task(struct kfifo *fifo, uint32_t itt)
{
      int i, nr_tasks = __kfifo_len(fifo) / sizeof(void*);
      struct iscsi_mgmt_task *task;

      debug_scsi("searching %d tasks\n", nr_tasks);

      for (i = 0; i < nr_tasks; i++) {
            __kfifo_get(fifo, (void*)&task, sizeof(void*));
            debug_scsi("check task %u\n", task->itt);

            if (task->itt == itt) {
                  debug_scsi("matched task\n");
                  return task;
            }

            __kfifo_put(fifo, (void*)&task, sizeof(void*));
      }
      return NULL;
}

static int iscsi_ctask_mtask_cleanup(struct iscsi_cmd_task *ctask)
{
      struct iscsi_conn *conn = ctask->conn;
      struct iscsi_session *session = conn->session;

      if (!ctask->mtask)
            return -EINVAL;

      if (!iscsi_remove_mgmt_task(conn->mgmtqueue, ctask->mtask->itt))
            list_del(&ctask->mtask->running);
      __kfifo_put(session->mgmtpool.queue, (void*)&ctask->mtask,
                sizeof(void*));
      ctask->mtask = NULL;
      return 0;
}

/*
 * session lock must be held
 */
static void fail_command(struct iscsi_conn *conn, struct iscsi_cmd_task *ctask,
                   int err)
{
      struct scsi_cmnd *sc;

      sc = ctask->sc;
      if (!sc)
            return;

      if (ctask->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--;
      else
            conn->session->tt->cleanup_cmd_task(conn, ctask);
      iscsi_ctask_mtask_cleanup(ctask);

      sc->result = err;
      scsi_set_resid(sc, scsi_bufflen(sc));
      if (conn->ctask == ctask)
            conn->ctask = NULL;
      /* release ref from queuecommand */
      __iscsi_put_ctask(ctask);
}

static void iscsi_suspend_tx(struct iscsi_conn *conn)
{
      set_bit(ISCSI_SUSPEND_BIT, &conn->suspend_tx);
      scsi_flush_work(conn->session->host);
}

static void iscsi_start_tx(struct iscsi_conn *conn)
{
      clear_bit(ISCSI_SUSPEND_BIT, &conn->suspend_tx);
      scsi_queue_work(conn->session->host, &conn->xmitwork);
}

int iscsi_eh_abort(struct scsi_cmnd *sc)
{
      struct Scsi_Host *host = sc->device->host;
      struct iscsi_session *session = iscsi_hostdata(host->hostdata);
      struct iscsi_cmd_task *ctask;
      struct iscsi_conn *conn;
      int rc;

      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) {
            debug_scsi("sc never reached iscsi layer or it completed.\n");
            spin_unlock_bh(&session->lock);
            mutex_unlock(&session->eh_mutex);
            return SUCCESS;
      }

      ctask = (struct iscsi_cmd_task *)sc->SCp.ptr;
      conn = ctask->conn;

      conn->eh_abort_cnt++;
      debug_scsi("aborting [sc %p itt 0x%x]\n", sc, ctask->itt);

      /*
       * If we are not logged in or we have started a new session
       * then let the host reset code handle this
       */
      if (session->state != ISCSI_STATE_LOGGED_IN ||
          sc->SCp.phase != session->age)
            goto failed;

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

      /* what should we do here ? */
      if (conn->ctask == ctask) {
            printk(KERN_INFO "iscsi: sc %p itt 0x%x partially sent. "
                   "Failing abort\n", sc, ctask->itt);
            goto failed;
      }

      if (ctask->state == ISCSI_TASK_PENDING) {
            fail_command(conn, ctask, DID_ABORT << 16);
            goto success;
      }

      conn->tmabort_state = TMABORT_INITIAL;
      rc = iscsi_exec_abort_task(sc, ctask);
      if (rc || sc->SCp.phase != session->age ||
          session->state != ISCSI_STATE_LOGGED_IN)
            goto failed;
      iscsi_ctask_mtask_cleanup(ctask);

      switch (conn->tmabort_state) {
      case TMABORT_SUCCESS:
            spin_unlock_bh(&session->lock);
            iscsi_suspend_tx(conn);
            /*
             * clean up task if aborted. grab the recv lock as a writer
             */
            write_lock_bh(conn->recv_lock);
            spin_lock(&session->lock);
            fail_command(conn, ctask, DID_ABORT << 16);
            spin_unlock(&session->lock);
            write_unlock_bh(conn->recv_lock);
            iscsi_start_tx(conn);
            goto success_unlocked;
      case TMABORT_NOT_FOUND:
            if (!ctask->sc) {
                  /* ctask completed before tmf abort response */
                  debug_scsi("sc completed while abort in progress\n");
                  goto success;
            }
            /* fall through */
      default:
            /* timedout or failed */
            spin_unlock_bh(&session->lock);
            iscsi_conn_failure(conn, ISCSI_ERR_CONN_FAILED);
            goto failed_unlocked;
      }

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

failed:
      spin_unlock_bh(&session->lock);
failed_unlocked:
      debug_scsi("abort failed [sc %lx itt 0x%x]\n", (long)sc, ctask->itt);
      mutex_unlock(&session->eh_mutex);
      return FAILED;
}
EXPORT_SYMBOL_GPL(iscsi_eh_abort);

int
iscsi_pool_init(struct iscsi_queue *q, int max, void ***items, int item_size)
{
      int i;

      *items = kmalloc(max * sizeof(void*), GFP_KERNEL);
      if (*items == NULL)
            return -ENOMEM;

      q->max = max;
      q->pool = kmalloc(max * sizeof(void*), GFP_KERNEL);
      if (q->pool == NULL) {
            kfree(*items);
            return -ENOMEM;
      }

      q->queue = kfifo_init((void*)q->pool, max * sizeof(void*),
                        GFP_KERNEL, NULL);
      if (q->queue == ERR_PTR(-ENOMEM)) {
            kfree(q->pool);
            kfree(*items);
            return -ENOMEM;
      }

      for (i = 0; i < max; i++) {
            q->pool[i] = kmalloc(item_size, GFP_KERNEL);
            if (q->pool[i] == NULL) {
                  int j;

                  for (j = 0; j < i; j++)
                        kfree(q->pool[j]);

                  kfifo_free(q->queue);
                  kfree(q->pool);
                  kfree(*items);
                  return -ENOMEM;
            }
            memset(q->pool[i], 0, item_size);
            (*items)[i] = q->pool[i];
            __kfifo_put(q->queue, (void*)&q->pool[i], sizeof(void*));
      }
      return 0;
}
EXPORT_SYMBOL_GPL(iscsi_pool_init);

void iscsi_pool_free(struct iscsi_queue *q, void **items)
{
      int i;

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

/*
 * iSCSI Session's hostdata organization:
 *
 *    *------------------* <== hostdata_session(host->hostdata)
 *    | ptr to class sess|
 *    |------------------| <== iscsi_hostdata(host->hostdata)
 *    | iscsi_session    |
 *    *------------------*
 */

#define hostdata_privsize(_sz)      (sizeof(unsigned long) + _sz + \
                         _sz % sizeof(unsigned long))

#define hostdata_session(_hostdata) (iscsi_ptr(*(unsigned long *)_hostdata))

/**
 * iscsi_session_setup - create iscsi cls session and host and session
 * @scsit: scsi transport template
 * @iscsit: iscsi transport template
 * @cmds_max: scsi host can queue
 * @qdepth: scsi host cmds per lun
 * @cmd_task_size: LLD ctask private data size
 * @mgmt_task_size: LLD mtask private data size
 * @initial_cmdsn: initial CmdSN
 * @hostno: host no allocated
 *
 * This can be used by software iscsi_transports that allocate
 * a session per scsi host.
 **/
struct iscsi_cls_session *
iscsi_session_setup(struct iscsi_transport *iscsit,
                struct scsi_transport_template *scsit,
                uint16_t cmds_max, uint16_t qdepth,
                int cmd_task_size, int mgmt_task_size,
                uint32_t initial_cmdsn, uint32_t *hostno)
{
      struct Scsi_Host *shost;
      struct iscsi_session *session;
      struct iscsi_cls_session *cls_session;
      int cmd_i;

      if (qdepth > ISCSI_MAX_CMD_PER_LUN || qdepth < 1) {
            if (qdepth != 0)
                  printk(KERN_ERR "iscsi: invalid queue depth of %d. "
                        "Queue depth must be between 1 and %d.\n",
                        qdepth, ISCSI_MAX_CMD_PER_LUN);
            qdepth = ISCSI_DEF_CMD_PER_LUN;
      }

      if (cmds_max < 2 || (cmds_max & (cmds_max - 1)) ||
          cmds_max >= ISCSI_MGMT_ITT_OFFSET) {
            if (cmds_max != 0)
                  printk(KERN_ERR "iscsi: invalid can_queue of %d. "
                         "can_queue must be a power of 2 and between "
                         "2 and %d - setting to %d.\n", cmds_max,
                         ISCSI_MGMT_ITT_OFFSET, ISCSI_DEF_XMIT_CMDS_MAX);
            cmds_max = ISCSI_DEF_XMIT_CMDS_MAX;
      }

      shost = scsi_host_alloc(iscsit->host_template,
                        hostdata_privsize(sizeof(*session)));
      if (!shost)
            return NULL;

      /* the iscsi layer takes one task for reserve */
      shost->can_queue = cmds_max - 1;
      shost->cmd_per_lun = qdepth;
      shost->max_id = 1;
      shost->max_channel = 0;
      shost->max_lun = iscsit->max_lun;
      shost->max_cmd_len = iscsit->max_cmd_len;
      shost->transportt = scsit;
      shost->transportt->create_work_queue = 1;
      *hostno = shost->host_no;

      session = iscsi_hostdata(shost->hostdata);
      memset(session, 0, sizeof(struct iscsi_session));
      session->host = shost;
      session->state = ISCSI_STATE_FREE;
      session->mgmtpool_max = ISCSI_MGMT_CMDS_MAX;
      session->cmds_max = cmds_max;
      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);

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

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

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

      spin_lock_init(&session->lock);

      /* initialize immediate command pool */
      if (iscsi_pool_init(&session->mgmtpool, session->mgmtpool_max,
                     (void***)&session->mgmt_cmds,
                     mgmt_task_size + sizeof(struct iscsi_mgmt_task)))
            goto mgmtpool_alloc_fail;


      /* pre-format immediate cmds pool with ITT */
      for (cmd_i = 0; cmd_i < session->mgmtpool_max; cmd_i++) {
            struct iscsi_mgmt_task *mtask = session->mgmt_cmds[cmd_i];

            if (mgmt_task_size)
                  mtask->dd_data = &mtask[1];
            mtask->itt = ISCSI_MGMT_ITT_OFFSET + cmd_i;
            INIT_LIST_HEAD(&mtask->running);
      }

      if (scsi_add_host(shost, NULL))
            goto add_host_fail;

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

      cls_session = iscsi_create_session(shost, iscsit, 0);
      if (!cls_session)
            goto module_put;
      *(unsigned long*)shost->hostdata = (unsigned long)cls_session;

      return cls_session;

module_put:
      module_put(iscsit->owner);
cls_session_fail:
      scsi_remove_host(shost);
add_host_fail:
      iscsi_pool_free(&session->mgmtpool, (void**)session->mgmt_cmds);
mgmtpool_alloc_fail:
      iscsi_pool_free(&session->cmdpool, (void**)session->cmds);
cmdpool_alloc_fail:
      scsi_host_put(shost);
      return NULL;
}
EXPORT_SYMBOL_GPL(iscsi_session_setup);

/**
 * iscsi_session_teardown - destroy session, host, and cls_session
 * shost: scsi host
 *
 * This can be used by software iscsi_transports that allocate
 * a session per scsi host.
 **/
void iscsi_session_teardown(struct iscsi_cls_session *cls_session)
{
      struct Scsi_Host *shost = iscsi_session_to_shost(cls_session);
      struct iscsi_session *session = iscsi_hostdata(shost->hostdata);
      struct module *owner = cls_session->transport->owner;

      iscsi_unblock_session(cls_session);
      scsi_remove_host(shost);

      iscsi_pool_free(&session->mgmtpool, (void**)session->mgmt_cmds);
      iscsi_pool_free(&session->cmdpool, (void**)session->cmds);

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

      iscsi_destroy_session(cls_session);
      scsi_host_put(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
 * @conn_idx: cid
 **/
struct iscsi_cls_conn *
iscsi_conn_setup(struct iscsi_cls_session *cls_session, uint32_t conn_idx)
{
      struct iscsi_session *session = class_to_transport_session(cls_session);
      struct iscsi_conn *conn;
      struct iscsi_cls_conn *cls_conn;
      char *data;

      cls_conn = iscsi_create_conn(cls_session, conn_idx);
      if (!cls_conn)
            return NULL;
      conn = cls_conn->dd_data;
      memset(conn, 0, 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->tmabort_state = TMABORT_INITIAL;
      INIT_LIST_HEAD(&conn->run_list);
      INIT_LIST_HEAD(&conn->mgmt_run_list);
      INIT_LIST_HEAD(&conn->xmitqueue);

      /* initialize general immediate & non-immediate PDU commands queue */
      conn->mgmtqueue = kfifo_alloc(session->mgmtpool_max * sizeof(void*),
                                  GFP_KERNEL, NULL);
      if (conn->mgmtqueue == ERR_PTR(-ENOMEM))
            goto mgmtqueue_alloc_fail;

      INIT_WORK(&conn->xmitwork, iscsi_xmitworker);

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

      data = kmalloc(ISCSI_DEF_MAX_RECV_SEG_LEN, GFP_KERNEL);
      if (!data)
            goto login_mtask_data_alloc_fail;
      conn->login_mtask->data = conn->data = data;

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

      return cls_conn;

login_mtask_data_alloc_fail:
      __kfifo_put(session->mgmtpool.queue, (void*)&conn->login_mtask,
                sizeof(void*));
login_mtask_alloc_fail:
      kfifo_free(conn->mgmtqueue);
mgmtqueue_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;

      spin_lock_bh(&session->lock);
      set_bit(ISCSI_SUSPEND_BIT, &conn->suspend_tx);
      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);
            printk(KERN_INFO "iscsi: scsi 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 */
      scsi_flush_work(session->host);

      spin_lock_bh(&session->lock);
      kfree(conn->data);
      kfree(conn->persistent_address);
      __kfifo_put(session->mgmtpool.queue, (void*)&conn->login_mtask,
                sizeof(void*));
      if (session->leadconn == conn)
            session->leadconn = NULL;
      spin_unlock_bh(&session->lock);

      kfifo_free(conn->mgmtqueue);

      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) {
            printk(KERN_ERR "iscsi: can't start unbound connection\n");
            return -EPERM;
      }

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

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

      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->tmabort_state = TMABORT_INITIAL;
            session->age++;
            spin_unlock_bh(&session->lock);

            iscsi_unblock_session(session_to_cls(session));
            wake_up(&conn->ehwait);
            return 0;
      case STOP_CONN_TERM:
            conn->stop_stage = 0;
            break;
      default:
            break;
      }
      spin_unlock_bh(&session->lock);

      return 0;
}
EXPORT_SYMBOL_GPL(iscsi_conn_start);

static void
flush_control_queues(struct iscsi_session *session, struct iscsi_conn *conn)
{
      struct iscsi_mgmt_task *mtask, *tmp;

      /* handle pending */
      while (__kfifo_get(conn->mgmtqueue, (void*)&mtask, sizeof(void*))) {
            if (mtask == conn->login_mtask)
                  continue;
            debug_scsi("flushing pending mgmt task itt 0x%x\n", mtask->itt);
            __kfifo_put(session->mgmtpool.queue, (void*)&mtask,
                      sizeof(void*));
      }

      /* handle running */
      list_for_each_entry_safe(mtask, tmp, &conn->mgmt_run_list, running) {
            debug_scsi("flushing running mgmt task itt 0x%x\n", mtask->itt);
            list_del(&mtask->running);

            if (mtask == conn->login_mtask)
                  continue;
            __kfifo_put(session->mgmtpool.queue, (void*)&mtask,
                     sizeof(void*));
      }

      conn->mtask = NULL;
}

/* Fail commands. Mutex and session lock held and recv side suspended */
static void fail_all_commands(struct iscsi_conn *conn)
{
      struct iscsi_cmd_task *ctask, *tmp;

      /* flush pending */
      list_for_each_entry_safe(ctask, tmp, &conn->xmitqueue, running) {
            debug_scsi("failing pending sc %p itt 0x%x\n", ctask->sc,
                     ctask->itt);
            fail_command(conn, ctask, DID_BUS_BUSY << 16);
      }

      /* fail all other running */
      list_for_each_entry_safe(ctask, tmp, &conn->run_list, running) {
            debug_scsi("failing in progress sc %p itt 0x%x\n",
                     ctask->sc, ctask->itt);
            fail_command(conn, ctask, DID_BUS_BUSY << 16);
      }

      conn->ctask = NULL;
}

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;
      }

      /*
       * The LLD either freed/unset the lock on us, or userspace called
       * stop but did not create a proper connection (connection was never
       * bound or it was unbound then stop was called).
       */
      if (!conn->recv_lock) {
            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;

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

      iscsi_suspend_tx(conn);

      write_lock_bh(conn->recv_lock);
      set_bit(ISCSI_SUSPEND_BIT, &conn->suspend_rx);
      write_unlock_bh(conn->recv_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) {
                  debug_scsi("blocking session\n");
                  iscsi_block_session(session_to_cls(session));
            }
      }

      /*
       * flush queues.
       */
      spin_lock_bh(&session->lock);
      fail_all_commands(conn);
      flush_control_queues(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:
            printk(KERN_ERR "iscsi: 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 = class_to_transport_session(cls_session);
      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);


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_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:
            kfree(session->username);
            session->username = kstrdup(buf, GFP_KERNEL);
            if (!session->username)
                  return -ENOMEM;
            break;
      case ISCSI_PARAM_USERNAME_IN:
            kfree(session->username_in);
            session->username_in = kstrdup(buf, GFP_KERNEL);
            if (!session->username_in)
                  return -ENOMEM;
            break;
      case ISCSI_PARAM_PASSWORD:
            kfree(session->password);
            session->password = kstrdup(buf, GFP_KERNEL);
            if (!session->password)
                  return -ENOMEM;
            break;
      case ISCSI_PARAM_PASSWORD_IN:
            kfree(session->password_in);
            session->password_in = kstrdup(buf, GFP_KERNEL);
            if (!session->password_in)
                  return -ENOMEM;
            break;
      case ISCSI_PARAM_TARGET_NAME:
            /* this should not change between logins */
            if (session->targetname)
                  break;

            session->targetname = kstrdup(buf, GFP_KERNEL);
            if (!session->targetname)
                  return -ENOMEM;
            break;
      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:
            /*
             * this is the address returned in discovery so it should
             * not change between logins.
             */
            if (conn->persistent_address)
                  break;

            conn->persistent_address = kstrdup(buf, GFP_KERNEL);
            if (!conn->persistent_address)
                  return -ENOMEM;
            break;
      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 Scsi_Host *shost = iscsi_session_to_shost(cls_session);
      struct iscsi_session *session = iscsi_hostdata(shost->hostdata);
      int len;

      switch(param) {
      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;
      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_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_session *session = iscsi_hostdata(shost->hostdata);
      int len;

      switch (param) {
      case ISCSI_HOST_PARAM_NETDEV_NAME:
            if (!session->netdev)
                  len = sprintf(buf, "%s\n", "default");
            else
                  len = sprintf(buf, "%s\n", session->netdev);
            break;
      case ISCSI_HOST_PARAM_HWADDRESS:
            if (!session->hwaddress)
                  len = sprintf(buf, "%s\n", "default");
            else
                  len = sprintf(buf, "%s\n", session->hwaddress);
            break;
      case ISCSI_HOST_PARAM_INITIATOR_NAME:
            if (!session->initiatorname)
                  len = sprintf(buf, "%s\n", "unknown");
            else
                  len = sprintf(buf, "%s\n", session->initiatorname);
            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_session *session = iscsi_hostdata(shost->hostdata);

      switch (param) {
      case ISCSI_HOST_PARAM_NETDEV_NAME:
            if (!session->netdev)
                  session->netdev = kstrdup(buf, GFP_KERNEL);
            break;
      case ISCSI_HOST_PARAM_HWADDRESS:
            if (!session->hwaddress)
                  session->hwaddress = kstrdup(buf, GFP_KERNEL);
            break;
      case ISCSI_HOST_PARAM_INITIATOR_NAME:
            if (!session->initiatorname)
                  session->initiatorname = kstrdup(buf, GFP_KERNEL);
            break;
      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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