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	Version: linux-6.0.1 spark-3.0.0 hadoop-3.2.0-src hadoop-3.3.0-src spark-2.4.7 linux-4.15.13 hadoop-2.7.4-src Revert   Change

 // SPDX-License-Identifier: GPL-2.0-or-later
 /*
  * 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
  */
 #include <linux/types.h>
 #include <linux/kfifo.h>
 #include <linux/delay.h>
 #include <linux/log2.h>
 #include <linux/slab.h>
 #include <linux/sched/signal.h>
 #include <linux/module.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>
 #include <trace/events/iscsi.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);  \
         iscsi_dbg_trace(trace_iscsi_dbg_conn,       \
                 &(_conn)->cls_conn->dev,    \
                 "%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);      \
         iscsi_dbg_trace(trace_iscsi_dbg_session,        \
                 &(_session)->cls_session->dev,      \
                 "%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);      \
         iscsi_dbg_trace(trace_iscsi_dbg_eh,         \
                 &(_session)->cls_session->dev,      \
                 "%s " dbg_fmt, __func__, ##arg);    \
     } while (0);
 
 #define ISCSI_CMD_COMPL_WAIT 5
 
 inline void iscsi_conn_queue_xmit(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_xmit);
 
 inline void iscsi_conn_queue_recv(struct iscsi_conn *conn)
 {
     struct Scsi_Host *shost = conn->session->host;
     struct iscsi_host *ihost = shost_priv(shost);
 
     if (ihost->workq && !test_bit(ISCSI_CONN_FLAG_SUSPEND_RX, &conn->flags))
         queue_work(ihost->workq, &conn->recvwork);
 }
 EXPORT_SYMBOL_GPL(iscsi_conn_queue_recv);
 
 static void __iscsi_update_cmdsn(struct iscsi_session *session,
                  uint32_t exp_cmdsn, uint32_t max_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;
 }
 
 void iscsi_update_cmdsn(struct iscsi_session *session, struct iscsi_nopin *hdr)
 {
     __iscsi_update_cmdsn(session, be32_to_cpu(hdr->exp_cmdsn),
                  be32_to_cpu(hdr->max_cmdsn));
 }
 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;
     hdr->lun = task->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;
 }
 
 /**
  * iscsi_check_tmf_restrictions - check if a task is affected by TMF
  * @task: iscsi task
  * @opcode: opcode to check for
  *
  * During TMF a task has to be checked if it's affected.
  * All unrelated I/O can be passed through, but I/O to the
  * affected LUN should be restricted.
  * If 'fast_abort' is set we won't be sending any I/O to the
  * affected LUN.
  * Otherwise the target is waiting for all TTTs to be completed,
  * so we have to send all outstanding Data-Out PDUs to the target.
  */
 static int iscsi_check_tmf_restrictions(struct iscsi_task *task, int opcode)
 {
     struct iscsi_session *session = task->conn->session;
     struct iscsi_tm *tmf = &session->tmhdr;
     u64 hdr_lun;
 
     if (session->tmf_state == TMF_INITIAL)
         return 0;
 
     if ((tmf->opcode & ISCSI_OPCODE_MASK) != ISCSI_OP_SCSI_TMFUNC)
         return 0;
 
     switch (ISCSI_TM_FUNC_VALUE(tmf)) {
     case ISCSI_TM_FUNC_LOGICAL_UNIT_RESET:
         /*
          * Allow PDUs for unrelated LUNs
          */
         hdr_lun = scsilun_to_int(&tmf->lun);
         if (hdr_lun != task->sc->device->lun)
             return 0;
         fallthrough;
     case ISCSI_TM_FUNC_TARGET_WARM_RESET:
         /*
          * Fail all SCSI cmd PDUs
          */
         if (opcode != ISCSI_OP_SCSI_DATA_OUT) {
             iscsi_session_printk(KERN_INFO, session,
                          "task [op %x itt 0x%x/0x%x] rejected.\n",
                          opcode, task->itt, task->hdr_itt);
             return -EACCES;
         }
         /*
          * And also all data-out PDUs in response to R2T
          * if fast_abort is set.
          */
         if (session->fast_abort) {
             iscsi_session_printk(KERN_INFO, session,
                          "task [op %x itt 0x%x/0x%x] fast abort.\n",
                          opcode, task->itt, task->hdr_itt);
             return -EACCES;
         }
         break;
     case ISCSI_TM_FUNC_ABORT_TASK:
         /*
          * the caller has already checked if the task
          * they want to abort was in the pending queue so if
          * we are here the cmd pdu has gone out already, and
          * we will only hit this for data-outs
          */
         if (opcode == ISCSI_OP_SCSI_DATA_OUT &&
             task->hdr_itt == tmf->rtt) {
             ISCSI_DBG_SESSION(session,
                       "Preventing task %x/%x from sending "
                       "data-out due to abort task in "
                       "progress\n", task->itt,
                       task->hdr_itt);
             return -EACCES;
         }
         break;
     }
 
     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_scsi_req *hdr;
     unsigned hdrlength, cmd_len, transfer_length;
     itt_t itt;
     int rc;
 
     rc = iscsi_check_tmf_restrictions(task, ISCSI_OP_SCSI_CMD);
     if (rc)
         return 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_scsi_req *)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, &hdr->lun);
     task->lun = hdr->lun;
     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_get_prot_op(sc) != SCSI_PROT_NORMAL)
         task->protected = true;
 
     transfer_length = scsi_transfer_length(sc);
     hdr->data_length = cpu_to_be32(transfer_length);
     if (sc->sc_data_direction == DMA_TO_DEVICE) {
         struct iscsi_r2t_info *r2t = &task->unsol_r2t;
 
         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 (transfer_length >= session->first_burst)
                 task->imm_count = min(session->first_burst,
                             conn->max_xmit_dlength);
             else
                 task->imm_count = min(transfer_length,
                               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,
                            transfer_length) -
                            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);
 
         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;
     hdr->cmdsn = task->cmdsn = cpu_to_be32(session->cmdsn);
 
     if (session->tt->init_task && session->tt->init_task(task))
         return -EIO;
 
     task->state = ISCSI_TASK_RUNNING;
     session->cmdsn++;
 
     conn->scsicmd_pdus_cnt++;
     ISCSI_DBG_SESSION(session, "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],
               task->itt, transfer_length,
               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 back_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;
     int oldstate = task->state;
 
     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_in(&session->cmdpool.queue, (void*)&task, sizeof(void*));
 
     if (sc) {
         /* SCSI eh reuses commands to verify us */
         iscsi_cmd(sc)->task = NULL;
         /*
          * queue command may call this to free the task, so
          * it will decide how to return sc to scsi-ml.
          */
         if (oldstate != ISCSI_TASK_REQUEUE_SCSIQ)
             scsi_done(sc);
     }
 }
 
 bool iscsi_get_task(struct iscsi_task *task)
 {
     return refcount_inc_not_zero(&task->refcount);
 }
 EXPORT_SYMBOL_GPL(iscsi_get_task);
 
 /**
  * __iscsi_put_task - drop the refcount on a task
  * @task: iscsi_task to drop the refcount on
  *
  * The back_lock must be held when calling in case it frees the task.
  */
 void __iscsi_put_task(struct iscsi_task *task)
 {
     if (refcount_dec_and_test(&task->refcount))
         iscsi_free_task(task);
 }
 EXPORT_SYMBOL_GPL(__iscsi_put_task);
 
 void iscsi_put_task(struct iscsi_task *task)
 {
     struct iscsi_session *session = task->conn->session;
 
     if (refcount_dec_and_test(&task->refcount)) {
         spin_lock_bh(&session->back_lock);
         iscsi_free_task(task);
         spin_unlock_bh(&session->back_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 back_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 ||
         task->state == ISCSI_TASK_REQUEUE_SCSIQ)
         return;
     WARN_ON_ONCE(task->state == ISCSI_TASK_FREE);
     task->state = state;
 
     if (READ_ONCE(conn->ping_task) == task)
         WRITE_ONCE(conn->ping_task, NULL);
 
     /* release get from queueing */
     __iscsi_put_task(task);
 }
 
 /**
  * iscsi_complete_scsi_task - finish scsi task normally
  * @task: iscsi task for scsi cmd
  * @exp_cmdsn: expected cmd sn in cpu format
  * @max_cmdsn: max cmd sn in cpu format
  *
  * This is used when drivers do not need or cannot perform
  * lower level pdu processing.
  *
  * Called with session back_lock
  */
 void iscsi_complete_scsi_task(struct iscsi_task *task,
                   uint32_t exp_cmdsn, uint32_t max_cmdsn)
 {
     struct iscsi_conn *conn = task->conn;
 
     ISCSI_DBG_SESSION(conn->session, "[itt 0x%x]\n", task->itt);
 
     conn->last_recv = jiffies;
     __iscsi_update_cmdsn(conn->session, exp_cmdsn, max_cmdsn);
     iscsi_complete_task(task, ISCSI_TASK_COMPLETED);
 }
 EXPORT_SYMBOL_GPL(iscsi_complete_scsi_task);
 
 /*
  * Must be called with back and frwd lock
  */
 static bool cleanup_queued_task(struct iscsi_task *task)
 {
     struct iscsi_conn *conn = task->conn;
     bool early_complete = false;
 
     /*
      * We might have raced where we handled a R2T early and got a response
      * but have not yet taken the task off the requeue list, then a TMF or
      * recovery happened and so we can still see it here.
      */
     if (task->state == ISCSI_TASK_COMPLETED)
         early_complete = true;
 
     if (!list_empty(&task->running)) {
         list_del_init(&task->running);
         /*
          * If it's on a list but still running this could be cleanup
          * from a TMF or session recovery.
          */
         if (task->state == ISCSI_TASK_RUNNING ||
             task->state == ISCSI_TASK_COMPLETED)
             __iscsi_put_task(task);
     }
 
     if (conn->session->running_aborted_task == task) {
         conn->session->running_aborted_task = NULL;
         __iscsi_put_task(task);
     }
 
     if (conn->task == task) {
         conn->task = NULL;
         __iscsi_put_task(task);
     }
 
     return early_complete;
 }
 
 /*
  * session back and frwd 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 (cleanup_queued_task(task))
         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 = task->sc;
     sc->result = err << 16;
     scsi_set_resid(sc, scsi_bufflen(sc));
     iscsi_complete_task(task, state);
 }
 
 static void fail_scsi_task(struct iscsi_task *task, int err)
 {
     struct iscsi_session *session = task->conn->session;
 
     spin_lock_bh(&session->back_lock);
     __fail_scsi_task(task, err);
     spin_unlock_bh(&session->back_lock);
 }
 
 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;
     uint8_t opcode = hdr->opcode & ISCSI_OPCODE_MASK;
 
     if (conn->session->state == ISCSI_STATE_LOGGING_OUT)
         return -ENOTCONN;
 
     if (opcode != ISCSI_OP_LOGIN && opcode != ISCSI_OP_TEXT)
         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 for normal session pdus.
          * If we start to send tmfs or nops as non-immediate then
          * we should start checking the cmdsn numbers for mgmt tasks.
          *
          * During discovery sessions iscsid sends TEXT as non immediate,
          * but we always only send one PDU at a time.
          */
         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;
 }
 
 /**
  * iscsi_alloc_mgmt_task - allocate and setup a mgmt task.
  * @conn: iscsi conn that the task will be sent on.
  * @hdr: iscsi pdu that will be sent.
  * @data: buffer for data segment if needed.
  * @data_size: length of data in bytes.
  */
 static struct iscsi_task *
 iscsi_alloc_mgmt_task(struct iscsi_conn *conn, struct iscsi_hdr *hdr,
               char *data, uint32_t data_size)
 {
     struct iscsi_session *session = conn->session;
     uint8_t opcode = hdr->opcode & ISCSI_OPCODE_MASK;
     struct iscsi_task *task;
     itt_t itt;
 
     if (session->state == ISCSI_STATE_TERMINATE ||
         !test_bit(ISCSI_CONN_FLAG_BOUND, &conn->flags))
         return NULL;
 
     if (opcode == ISCSI_OP_LOGIN || opcode == ISCSI_OP_TEXT) {
         /*
          * 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().
          */
         if (conn->login_task->state != ISCSI_TASK_FREE) {
             iscsi_conn_printk(KERN_ERR, conn, "Login/Text in "
                       "progress. Cannot start new task.\n");
             return NULL;
         }
 
         if (data_size > ISCSI_DEF_MAX_RECV_SEG_LEN) {
             iscsi_conn_printk(KERN_ERR, conn, "Invalid buffer len of %u for login task. Max len is %u\n", data_size, ISCSI_DEF_MAX_RECV_SEG_LEN);
             return NULL;
         }
 
         task = conn->login_task;
     } else {
         if (session->state != ISCSI_STATE_LOGGED_IN)
             return NULL;
 
         if (data_size != 0) {
             iscsi_conn_printk(KERN_ERR, conn, "Can not send data buffer of len %u for op 0x%x\n", data_size, opcode);
             return NULL;
         }
 
         BUG_ON(conn->c_stage == ISCSI_CONN_INITIAL_STAGE);
         BUG_ON(conn->c_stage == ISCSI_CONN_STOPPED);
 
         if (!kfifo_out(&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.
      */
     refcount_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);
     }
 
     return task;
 
 free_task:
     iscsi_put_task(task);
     return NULL;
 }
 
 /**
  * iscsi_send_mgmt_task - Send task created with iscsi_alloc_mgmt_task.
  * @task: iscsi task to send.
  *
  * On failure this returns a non-zero error code, and the driver must free
  * the task with iscsi_put_task;
  */
 static int iscsi_send_mgmt_task(struct iscsi_task *task)
 {
     struct iscsi_conn *conn = task->conn;
     struct iscsi_session *session = conn->session;
     struct iscsi_host *ihost = shost_priv(conn->session->host);
     int rc = 0;
 
     if (!ihost->workq) {
         rc = iscsi_prep_mgmt_task(conn, task);
         if (rc)
             return rc;
 
         rc = session->tt->xmit_task(task);
         if (rc)
             return rc;
     } else {
         list_add_tail(&task->running, &conn->mgmtqueue);
         iscsi_conn_queue_xmit(conn);
     }
 
     return 0;
 }
 
 static int __iscsi_conn_send_pdu(struct iscsi_conn *conn, struct iscsi_hdr *hdr,
                  char *data, uint32_t data_size)
 {
     struct iscsi_task *task;
     int rc;
 
     task = iscsi_alloc_mgmt_task(conn, hdr, data, data_size);
     if (!task)
         return -ENOMEM;
 
     rc = iscsi_send_mgmt_task(task);
     if (rc)
         iscsi_put_task(task);
     return rc;
 }
 
 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->frwd_lock);
     if (__iscsi_conn_send_pdu(conn, hdr, data, data_size))
         err = -EPERM;
     spin_unlock_bh(&session->frwd_lock);
     return err;
 }
 EXPORT_SYMBOL_GPL(iscsi_conn_send_pdu);
 
 /**
  * iscsi_scsi_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. called under back_lock
  **/
 static void iscsi_scsi_cmd_rsp(struct iscsi_conn *conn, struct iscsi_hdr *hdr,
                    struct iscsi_task *task, char *data,
                    int datalen)
 {
     struct iscsi_scsi_rsp *rhdr = (struct iscsi_scsi_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 (task->protected) {
         sector_t sector;
         u8 ascq;
 
         /**
          * Transports that didn't implement check_protection
          * callback but still published T10-PI support to scsi-mid
          * deserve this BUG_ON.
          **/
         BUG_ON(!session->tt->check_protection);
 
         ascq = session->tt->check_protection(task, &sector);
         if (ascq) {
             scsi_build_sense(sc, 1, ILLEGAL_REQUEST, 0x10, ascq);
             scsi_set_sense_information(sc->sense_buffer,
                            SCSI_SENSE_BUFFERSIZE,
                            sector);
             goto out;
         }
     }
 
     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)) {
         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
  *
  * iscsi_data_in_rsp sets up the scsi_cmnd fields based on the data received
  * then completes the command and task. called under back_lock
  **/
 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 <= sc->sdb.length))
             scsi_set_resid(sc, 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;
     struct iscsi_session *session = conn->session;
 
     conn->exp_statsn = be32_to_cpu(hdr->statsn) + 1;
     conn->tmfrsp_pdus_cnt++;
 
     if (session->tmf_state != TMF_QUEUED)
         return;
 
     if (tmf->response == ISCSI_TMF_RSP_COMPLETE)
         session->tmf_state = TMF_SUCCESS;
     else if (tmf->response == ISCSI_TMF_RSP_NO_TASK)
         session->tmf_state = TMF_NOT_FOUND;
     else
         session->tmf_state = TMF_FAILED;
     wake_up(&session->ehwait);
 }
 
 static int iscsi_send_nopout(struct iscsi_conn *conn, struct iscsi_nopin *rhdr)
 {
         struct iscsi_nopout hdr;
     struct iscsi_task *task;
 
     if (!rhdr) {
         if (READ_ONCE(conn->ping_task))
             return -EINVAL;
     }
 
     memset(&hdr, 0, sizeof(struct iscsi_nopout));
     hdr.opcode = ISCSI_OP_NOOP_OUT | ISCSI_OP_IMMEDIATE;
     hdr.flags = ISCSI_FLAG_CMD_FINAL;
 
     if (rhdr) {
         hdr.lun = rhdr->lun;
         hdr.ttt = rhdr->ttt;
         hdr.itt = RESERVED_ITT;
     } else
         hdr.ttt = RESERVED_ITT;
 
     task = iscsi_alloc_mgmt_task(conn, (struct iscsi_hdr *)&hdr, NULL, 0);
     if (!task)
         return -ENOMEM;
 
     if (!rhdr)
         WRITE_ONCE(conn->ping_task, task);
 
     if (iscsi_send_mgmt_task(task)) {
         if (!rhdr)
             WRITE_ONCE(conn->ping_task, NULL);
         iscsi_put_task(task);
 
         iscsi_conn_printk(KERN_ERR, conn, "Could not send nopout\n");
         return -EIO;
     } else if (!rhdr) {
         /* only track our nops */
         conn->last_ping = jiffies;
     }
 
     return 0;
 }
 
 /**
  * iscsi_nop_out_rsp - SCSI NOP Response processing
  * @task: scsi command task
  * @nop: the nop structure
  * @data: where to put the data
  * @datalen: length of data
  *
  * iscsi_nop_out_rsp handles nop response from use or
  * from user space. called under back_lock
  **/
 static int iscsi_nop_out_rsp(struct iscsi_task *task,
                  struct iscsi_nopin *nop, char *data, int datalen)
 {
     struct iscsi_conn *conn = task->conn;
     int rc = 0;
 
     if (READ_ONCE(conn->ping_task) != task) {
         /*
          * If this is not in response to one of our
          * nops then it must be from userspace.
          */
         if (iscsi_recv_pdu(conn->cls_conn, (struct iscsi_hdr *)nop,
                    data, datalen))
             rc = ISCSI_ERR_CONN_FAILED;
     } else
         mod_timer(&conn->transport_timer, jiffies + conn->recv_timeout);
     iscsi_complete_task(task, ISCSI_TASK_COMPLETED);
     return rc;
 }
 
 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;
     int opcode, rc = 0;
 
     conn->exp_statsn = be32_to_cpu(reject->statsn) + 1;
 
     if (ntoh24(reject->dlength) > datalen ||
         ntoh24(reject->dlength) < sizeof(struct iscsi_hdr)) {
         iscsi_conn_printk(KERN_ERR, conn, "Cannot handle rejected "
                   "pdu. Invalid data length (pdu dlength "
                   "%u, datalen %d\n", ntoh24(reject->dlength),
                   datalen);
         return ISCSI_ERR_PROTO;
     }
     memcpy(&rejected_pdu, data, sizeof(struct iscsi_hdr));
     opcode = rejected_pdu.opcode & ISCSI_OPCODE_MASK;
 
     switch (reject->reason) {
     case ISCSI_REASON_DATA_DIGEST_ERROR:
         iscsi_conn_printk(KERN_ERR, conn,
                   "pdu (op 0x%x itt 0x%x) rejected "
                   "due to DataDigest error.\n",
                   opcode, rejected_pdu.itt);
         break;
     case ISCSI_REASON_IMM_CMD_REJECT:
         iscsi_conn_printk(KERN_ERR, conn,
                   "pdu (op 0x%x itt 0x%x) rejected. Too many "
                   "immediate commands.\n",
                   opcode, rejected_pdu.itt);
         /*
          * We only send one TMF at a time so if the target could not
          * handle it, then it should get fixed (RFC mandates that
          * a target can handle one immediate TMF per conn).
          *
          * For nops-outs, we could have sent more than one if
          * the target is sending us lots of nop-ins
          */
         if (opcode != ISCSI_OP_NOOP_OUT)
             return 0;
 
         if (rejected_pdu.itt == cpu_to_be32(ISCSI_RESERVED_TAG)) {
             /*
              * nop-out in response to target's nop-out rejected.
              * Just resend.
              */
             /* In RX path we are under back lock */
             spin_unlock(&conn->session->back_lock);
             spin_lock(&conn->session->frwd_lock);
             iscsi_send_nopout(conn,
                       (struct iscsi_nopin*)&rejected_pdu);
             spin_unlock(&conn->session->frwd_lock);
             spin_lock(&conn->session->back_lock);
         } else {
             struct iscsi_task *task;
             /*
              * Our nop as ping got dropped. We know the target
              * and transport are ok so just clean up
              */
             task = iscsi_itt_to_task(conn, rejected_pdu.itt);
             if (!task) {
                 iscsi_conn_printk(KERN_ERR, conn,
                          "Invalid pdu reject. Could "
                          "not lookup rejected task.\n");
                 rc = ISCSI_ERR_BAD_ITT;
             } else
                 rc = iscsi_nop_out_rsp(task,
                     (struct iscsi_nopin*)&rejected_pdu,
                     NULL, 0);
         }
         break;
     default:
         iscsi_conn_printk(KERN_ERR, conn,
                   "pdu (op 0x%x itt 0x%x) rejected. Reason "
                   "code 0x%x\n", rejected_pdu.opcode,
                   rejected_pdu.itt, reject->reason);
         break;
     }
     return rc;
 }
 
 /**
  * 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 back_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 back_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;
 
             /* In RX path we are under back lock */
             spin_unlock(&session->back_lock);
             spin_lock(&session->frwd_lock);
             iscsi_send_nopout(conn, (struct iscsi_nopin*)hdr);
             spin_unlock(&session->frwd_lock);
             spin_lock(&session->back_lock);
             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;
 
         rc = iscsi_nop_out_rsp(task, (struct iscsi_nopin*)hdr,
                        data, datalen);
         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->back_lock);
     rc = __iscsi_complete_pdu(conn, hdr, data, datalen);
     spin_unlock(&conn->session->back_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 back_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 (iscsi_cmd(task->sc)->age != conn->session->age) {
         iscsi_session_printk(KERN_ERR, conn->session,
                   "task's session age %d, expected %d\n",
                   iscsi_cmd(task->sc)->age, 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;
 
     spin_lock_bh(&session->frwd_lock);
     conn = session->leadconn;
     if (session->state == ISCSI_STATE_TERMINATE || !conn) {
         spin_unlock_bh(&session->frwd_lock);
         return;
     }
 
     iscsi_get_conn(conn->cls_conn);
     spin_unlock_bh(&session->frwd_lock);
     /*
      * 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);
     iscsi_put_conn(conn->cls_conn);
 }
 EXPORT_SYMBOL_GPL(iscsi_session_failure);
 
 static bool iscsi_set_conn_failed(struct iscsi_conn *conn)
 {
     struct iscsi_session *session = conn->session;
 
     if (session->state == ISCSI_STATE_FAILED)
         return false;
 
     if (conn->stop_stage == 0)
         session->state = ISCSI_STATE_FAILED;
 
     set_bit(ISCSI_CONN_FLAG_SUSPEND_TX, &conn->flags);
     set_bit(ISCSI_CONN_FLAG_SUSPEND_RX, &conn->flags);
     return true;
 }
 
 void iscsi_conn_failure(struct iscsi_conn *conn, enum iscsi_err err)
 {
     struct iscsi_session *session = conn->session;
     bool needs_evt;
 
     spin_lock_bh(&session->frwd_lock);
     needs_evt = iscsi_set_conn_failed(conn);
     spin_unlock_bh(&session->frwd_lock);
 
     if (needs_evt)
         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,
                bool was_requeue)
 {
     int rc;
 
     if (!conn->task) {
         /*
          * Take a ref so we can access it after xmit_task().
          *
          * This should never fail because the failure paths will have
          * stopped the xmit thread.
          */
         if (!iscsi_get_task(task)) {
             WARN_ON_ONCE(1);
             return 0;
         }
     } else {
         /* Already have a ref from when we failed to send it last call */
         conn->task = NULL;
     }
 
     /*
      * If this was a requeue for a R2T we have an extra ref on the task in
      * case a bad target sends a cmd rsp before we have handled the task.
      */
     if (was_requeue)
         iscsi_put_task(task);
 
     /*
      * Do this after dropping the extra ref because if this was a requeue
      * it's removed from that list and cleanup_queued_task would miss it.
      */
     if (test_bit(ISCSI_CONN_FLAG_SUSPEND_TX, &conn->flags)) {
         /*
          * Save the task and ref in case we weren't cleaning up this
          * task and get woken up again.
          */
         conn->task = task;
         return -ENODATA;
     }
 
     spin_unlock_bh(&conn->session->frwd_lock);
     rc = conn->session->tt->xmit_task(task);
     spin_lock_bh(&conn->session->frwd_lock);
     if (!rc) {
         /* done with this task */
         task->last_xfer = jiffies;
     } else {
         /*
          * get an extra ref that is released next time we access it
          * as conn->task above.
          */
         iscsi_get_task(task);
         conn->task = task;
     }
 
     iscsi_put_task(task);
     return rc;
 }
 
 /**
  * iscsi_requeue_task - requeue task to run from session workqueue
  * @task: task to requeue
  *
  * Callers must have taken a ref to the task that is going to be requeued.
  */
 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
      */
     spin_lock_bh(&conn->session->frwd_lock);
     if (list_empty(&task->running)) {
         list_add_tail(&task->running, &conn->requeue);
     } else {
         /*
          * Don't need the extra ref since it's already requeued and
          * has a ref.
          */
         iscsi_put_task(task);
     }
     iscsi_conn_queue_xmit(conn);
     spin_unlock_bh(&conn->session->frwd_lock);
 }
 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)
 {
     struct iscsi_task *task;
     int rc = 0;
 
     spin_lock_bh(&conn->session->frwd_lock);
     if (test_bit(ISCSI_CONN_FLAG_SUSPEND_TX, &conn->flags)) {
         ISCSI_DBG_SESSION(conn->session, "Tx suspended!\n");
         spin_unlock_bh(&conn->session->frwd_lock);
         return -ENODATA;
     }
 
     if (conn->task) {
         rc = iscsi_xmit_task(conn, conn->task, false);
             if (rc)
                 goto done;
     }
 
     /*
      * 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)) {
         task = list_entry(conn->mgmtqueue.next, struct iscsi_task,
                   running);
         list_del_init(&task->running);
         if (iscsi_prep_mgmt_task(conn, task)) {
             /* regular RX path uses back_lock */
             spin_lock_bh(&conn->session->back_lock);
             __iscsi_put_task(task);
             spin_unlock_bh(&conn->session->back_lock);
             continue;
         }
         rc = iscsi_xmit_task(conn, task, false);
         if (rc)
             goto done;
     }
 
 check_requeue:
     while (!list_empty(&conn->requeue)) {
         /*
          * we always do fastlogout - conn stop code will clean up.
          */
         if (conn->session->state == ISCSI_STATE_LOGGING_OUT)
             break;
 
         task = list_entry(conn->requeue.next, struct iscsi_task,
                   running);
 
         if (iscsi_check_tmf_restrictions(task, ISCSI_OP_SCSI_DATA_OUT))
             break;
 
         list_del_init(&task->running);
         rc = iscsi_xmit_task(conn, task, true);
         if (rc)
             goto done;
         if (!list_empty(&conn->mgmtqueue))
             goto check_mgmt;
     }
 
     /* process pending command queue */
     while (!list_empty(&conn->cmdqueue)) {
         task = list_entry(conn->cmdqueue.next, struct iscsi_task,
                   running);
         list_del_init(&task->running);
         if (conn->session->state == ISCSI_STATE_LOGGING_OUT) {
             fail_scsi_task(task, DID_IMM_RETRY);
             continue;
         }
         rc = iscsi_prep_scsi_cmd_pdu(task);
         if (rc) {
             if (rc == -ENOMEM || rc == -EACCES)
                 fail_scsi_task(task, DID_IMM_RETRY);
             else
                 fail_scsi_task(task, DID_ABORT);
             continue;
         }
         rc = iscsi_xmit_task(conn, task, false);
         if (rc)
             goto done;
         /*
          * 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;
         if (!list_empty(&conn->requeue))
             goto check_requeue;
     }
 
     spin_unlock_bh(&conn->session->frwd_lock);
     return -ENODATA;
 
 done:
     spin_unlock_bh(&conn->session->frwd_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_out(&conn->session->cmdpool.queue,
              (void *) &task, sizeof(void *)))
         return NULL;
 
     iscsi_cmd(sc)->age = conn->session->age;
     iscsi_cmd(sc)->task = task;
 
     refcount_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;
     task->protected = false;
     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_Host *host, struct scsi_cmnd *sc)
 {
     struct iscsi_cls_session *cls_session;
     struct iscsi_host *ihost;
     int reason = 0;
     struct iscsi_session *session;
     struct iscsi_conn *conn;
     struct iscsi_task *task = NULL;
 
     sc->result = 0;
     iscsi_cmd(sc)->task = NULL;
 
     ihost = shost_priv(host);
 
     cls_session = starget_to_session(scsi_target(sc->device));
     session = cls_session->dd_data;
     spin_lock_bh(&session->frwd_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:
             /*
              * cmds should fail during shutdown, if the session
              * state is bad, allowing completion to happen
              */
             if (unlikely(system_state != SYSTEM_RUNNING)) {
                 reason = FAILURE_SESSION_FAILED;
                 sc->result = DID_NO_CONNECT << 16;
                 break;
             }
             fallthrough;
         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 (test_bit(ISCSI_CONN_FLAG_SUSPEND_TX, &conn->flags)) {
         reason = FAILURE_SESSION_IN_RECOVERY;
         sc->result = DID_REQUEUE << 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 == -EACCES) {
                 reason = FAILURE_OOM;
                 goto prepd_reject;
             } else {
                 sc->result = DID_ABORT << 16;
                 goto prepd_fault;
             }
         }
         if (session->tt->xmit_task(task)) {
             session->cmdsn--;
             reason = FAILURE_SESSION_NOT_READY;
             goto prepd_reject;
         }
     } else {
         list_add_tail(&task->running, &conn->cmdqueue);
         iscsi_conn_queue_xmit(conn);
     }
 
     session->queued_cmdsn++;
     spin_unlock_bh(&session->frwd_lock);
     return 0;
 
 prepd_reject:
     spin_lock_bh(&session->back_lock);
     iscsi_complete_task(task, ISCSI_TASK_REQUEUE_SCSIQ);
     spin_unlock_bh(&session->back_lock);
 reject:
     spin_unlock_bh(&session->frwd_lock);
     ISCSI_DBG_SESSION(session, "cmd 0x%x rejected (%d)\n",
               sc->cmnd[0], reason);
     return SCSI_MLQUEUE_TARGET_BUSY;
 
 prepd_fault:
     spin_lock_bh(&session->back_lock);
     iscsi_complete_task(task, ISCSI_TASK_REQUEUE_SCSIQ);
     spin_unlock_bh(&session->back_lock);
 fault:
     spin_unlock_bh(&session->frwd_lock);
     ISCSI_DBG_SESSION(session, "iscsi: cmd 0x%x is not queued (%d)\n",
               sc->cmnd[0], reason);
     scsi_set_resid(sc, scsi_bufflen(sc));
     scsi_done(sc);
     return 0;
 }
 EXPORT_SYMBOL_GPL(iscsi_queuecommand);
 
 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);
 
 static void iscsi_tmf_timedout(struct timer_list *t)
 {
     struct iscsi_session *session = from_timer(session, t, tmf_timer);
 
     spin_lock(&session->frwd_lock);
     if (session->tmf_state == TMF_QUEUED) {
         session->tmf_state = TMF_TIMEDOUT;
         ISCSI_DBG_EH(session, "tmf timedout\n");
         /* unblock eh_abort() */
         wake_up(&session->ehwait);
     }
     spin_unlock(&session->frwd_lock);
 }
 
 static int iscsi_exec_task_mgmt_fn(struct iscsi_conn *conn,
                    struct iscsi_tm *hdr, int age,
                    int timeout)
     __must_hold(&session->frwd_lock)
 {
     struct iscsi_session *session = conn->session;
 
     if (__iscsi_conn_send_pdu(conn, (struct iscsi_hdr *)hdr, NULL, 0)) {
         spin_unlock_bh(&session->frwd_lock);
         iscsi_conn_printk(KERN_ERR, conn, "Could not send TMF.\n");
         iscsi_conn_failure(conn, ISCSI_ERR_CONN_FAILED);
         spin_lock_bh(&session->frwd_lock);
         return -EPERM;
     }
     conn->tmfcmd_pdus_cnt++;
     session->tmf_timer.expires = timeout * HZ + jiffies;
     add_timer(&session->tmf_timer);
     ISCSI_DBG_EH(session, "tmf set timeout\n");
 
     spin_unlock_bh(&session->frwd_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(session->ehwait, age != session->age ||
                  session->state != ISCSI_STATE_LOGGED_IN ||
                  session->tmf_state != TMF_QUEUED);
     if (signal_pending(current))
         flush_signals(current);
     del_timer_sync(&session->tmf_timer);
 
     mutex_lock(&session->eh_mutex);
     spin_lock_bh(&session->frwd_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 frwd lock held and xmit thread flushed.
  */
 static void fail_scsi_tasks(struct iscsi_conn *conn, u64 lun, int error)
 {
     struct iscsi_session *session = conn->session;
     struct iscsi_task *task;
     int i;
 
 restart_cmd_loop:
     spin_lock_bh(&session->back_lock);
     for (i = 0; i < session->cmds_max; i++) {
         task = session->cmds[i];
         if (!task->sc || task->state == ISCSI_TASK_FREE)
             continue;
 
         if (lun != -1 && lun != task->sc->device->lun)
             continue;
         /*
          * The cmd is completing but if this is called from an eh
          * callout path then when we return scsi-ml owns the cmd. Wait
          * for the completion path to finish freeing the cmd.
          */
         if (!iscsi_get_task(task)) {
             spin_unlock_bh(&session->back_lock);
             spin_unlock_bh(&session->frwd_lock);
             udelay(ISCSI_CMD_COMPL_WAIT);
             spin_lock_bh(&session->frwd_lock);
             goto restart_cmd_loop;
         }
 
         ISCSI_DBG_SESSION(session,
                   "failing sc %p itt 0x%x state %d\n",
                   task->sc, task->itt, task->state);
         __fail_scsi_task(task, error);
         __iscsi_put_task(task);
     }
     spin_unlock_bh(&session->back_lock);
 }
 
 /**
  * iscsi_suspend_queue - suspend iscsi_queuecommand
  * @conn: iscsi conn to stop queueing IO on
  *
  * This grabs the session frwd_lock to make sure no one is in
  * xmit_task/queuecommand, and then sets suspend to prevent
  * new commands from being queued. This only needs to be called
  * by offload drivers that need to sync a path like ep disconnect
  * with the iscsi_queuecommand/xmit_task. To start IO again libiscsi
  * will call iscsi_start_tx and iscsi_unblock_session when in FFP.
  */
 void iscsi_suspend_queue(struct iscsi_conn *conn)
 {
     spin_lock_bh(&conn->session->frwd_lock);
     set_bit(ISCSI_CONN_FLAG_SUSPEND_TX, &conn->flags);
     spin_unlock_bh(&conn->session->frwd_lock);
 }
 EXPORT_SYMBOL_GPL(iscsi_suspend_queue);
 
 /**
  * iscsi_suspend_tx - suspend iscsi_data_xmit
  * @conn: iscsi conn to stop processing IO on.
  *
  * This function sets the suspend bit to prevent iscsi_data_xmit
  * from sending new IO, and if work is queued on the xmit thread
  * it will wait for it to be completed.
  */
 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_CONN_FLAG_SUSPEND_TX, &conn->flags);
     if (ihost->workq)
         flush_work(&conn->xmitwork);
 }
 EXPORT_SYMBOL_GPL(iscsi_suspend_tx);
 
 static void iscsi_start_tx(struct iscsi_conn *conn)
 {
     clear_bit(ISCSI_CONN_FLAG_SUSPEND_TX, &conn->flags);
     iscsi_conn_queue_xmit(conn);
 }
 
 /**
  * iscsi_suspend_rx - Prevent recvwork from running again.
  * @conn: iscsi conn to stop.
  */
 void iscsi_suspend_rx(struct iscsi_conn *conn)
 {
     struct Scsi_Host *shost = conn->session->host;
     struct iscsi_host *ihost = shost_priv(shost);
 
     set_bit(ISCSI_CONN_FLAG_SUSPEND_RX, &conn->flags);
     if (ihost->workq)
         flush_work(&conn->recvwork);
 }
 EXPORT_SYMBOL_GPL(iscsi_suspend_rx);
 
 /*
  * 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 (READ_ONCE(conn->ping_task) &&
         time_before_eq(conn->last_recv + (conn->recv_timeout * HZ) +
                (conn->ping_timeout * HZ), jiffies))
         return 1;
     else
         return 0;
 }
 
 enum blk_eh_timer_return iscsi_eh_cmd_timed_out(struct scsi_cmnd *sc)
 {
     enum blk_eh_timer_return rc = BLK_EH_DONE;
     struct iscsi_task *task = NULL, *running_task;
     struct iscsi_cls_session *cls_session;
     struct iscsi_session *session;
     struct iscsi_conn *conn;
     int i;
 
     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_bh(&session->frwd_lock);
     spin_lock(&session->back_lock);
     task = iscsi_cmd(sc)->task;
     if (!task) {
         /*
          * Raced with completion. Blk layer has taken ownership
          * so let timeout code complete it now.
          */
         rc = BLK_EH_DONE;
         spin_unlock(&session->back_lock);
         goto done;
     }
     if (!iscsi_get_task(task)) {
         /*
          * Racing with the completion path right now, so give it more
          * time so that path can complete it like normal.
          */
         rc = BLK_EH_RESET_TIMER;
         task = NULL;
         spin_unlock(&session->back_lock);
         goto done;
     }
     spin_unlock(&session->back_lock);
 
     if (session->state != ISCSI_STATE_LOGGED_IN) {
         /*
          * During shutdown, if session is prematurely disconnected,
          * recovery won't happen and there will be hung cmds. Not
          * handling cmds would trigger EH, also bad in this case.
          * Instead, handle cmd, allow completion to happen and let
          * upper layer to deal with the result.
          */
         if (unlikely(system_state != SYSTEM_RUNNING)) {
             sc->result = DID_NO_CONNECT << 16;
             ISCSI_DBG_EH(session, "sc on shutdown, handled\n");
             rc = BLK_EH_DONE;
             goto done;
         }
         /*
          * 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;
     }
 
     /*
      * 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(task->last_xfer, task->last_timeout)) {
         ISCSI_DBG_EH(session, "Command making progress. Asking "
                  "scsi-ml for more time to complete. "
                  "Last data xfer 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;
     }
 
     spin_lock(&session->back_lock);
     for (i = 0; i < conn->session->cmds_max; i++) {
         running_task = conn->session->cmds[i];
         if (!running_task->sc || running_task == task ||
              running_task->state != ISCSI_TASK_RUNNING)
             continue;
 
         /*
          * Only check if cmds started before this one have made
          * progress, or this could never fail
          */
         if (time_after(running_task->sc->jiffies_at_alloc,
                    task->sc->jiffies_at_alloc))
             continue;
 
         if (time_after(running_task->last_xfer, task->last_timeout)) {
             /*
              * This task has not made progress, but a task
              * started before us has transferred data since
              * we started/last-checked. We could be queueing
              * too many tasks or the LU is bad.
              *
              * If the device is bad the cmds ahead of us on
              * other devs will complete, and this loop will
              * eventually fail starting the scsi eh.
              */
             ISCSI_DBG_EH(session, "Command has not made progress "
                      "but commands ahead of it have. "
                      "Asking scsi-ml for more time to "
                      "complete. Our last xfer vs running task "
                      "last xfer %lu/%lu. Last check %lu.\n",
                      task->last_xfer, running_task->last_xfer,
                      task->last_timeout);
             spin_unlock(&session->back_lock);
             rc = BLK_EH_RESET_TIMER;
             goto done;
         }
     }
     spin_unlock(&session->back_lock);
 
     /* 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 (READ_ONCE(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:
     spin_unlock_bh(&session->frwd_lock);
 
     if (task) {
         task->last_timeout = jiffies;
         iscsi_put_task(task);
     }
     ISCSI_DBG_EH(session, "return %s\n", rc == BLK_EH_RESET_TIMER ?
              "timer reset" : "shutdown or nh");
     return rc;
 }
 EXPORT_SYMBOL_GPL(iscsi_eh_cmd_timed_out);
 
 static void iscsi_check_transport_timeouts(struct timer_list *t)
 {
     struct iscsi_conn *conn = from_timer(conn, t, transport_timer);
     struct iscsi_session *session = conn->session;
     unsigned long recv_timeout, next_timeout = 0, last_recv;
 
     spin_lock(&session->frwd_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->frwd_lock);
         iscsi_conn_failure(conn, ISCSI_ERR_NOP_TIMEDOUT);
         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");
         if (iscsi_send_nopout(conn, NULL))
             next_timeout = jiffies + (1 * HZ);
         else
             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->frwd_lock);
 }
 
 /**
  * iscsi_conn_unbind - prevent queueing to conn.
  * @cls_conn: iscsi conn ep is bound to.
  * @is_active: is the conn in use for boot or is this for EH/termination
  *
  * This must be called by drivers implementing the ep_disconnect callout.
  * It disables queueing to the connection from libiscsi in preparation for
  * an ep_disconnect call.
  */
 void iscsi_conn_unbind(struct iscsi_cls_conn *cls_conn, bool is_active)
 {
     struct iscsi_session *session;
     struct iscsi_conn *conn;
 
     if (!cls_conn)
         return;
 
     conn = cls_conn->dd_data;
     session = conn->session;
     /*
      * Wait for iscsi_eh calls to exit. We don't wait for the tmf to
      * complete or timeout. The caller just wants to know what's running
      * is everything that needs to be cleaned up, and no cmds will be
      * queued.
      */
     mutex_lock(&session->eh_mutex);
 
     iscsi_suspend_queue(conn);
     iscsi_suspend_tx(conn);
 
     spin_lock_bh(&session->frwd_lock);
     clear_bit(ISCSI_CONN_FLAG_BOUND, &conn->flags);
 
     if (!is_active) {
         /*
          * if logout timed out before userspace could even send a PDU
          * the state might still be in ISCSI_STATE_LOGGED_IN and
          * allowing new cmds and TMFs.
          */
         if (session->state == ISCSI_STATE_LOGGED_IN)
             iscsi_set_conn_failed(conn);
     }
     spin_unlock_bh(&session->frwd_lock);
     mutex_unlock(&session->eh_mutex);
 }
 EXPORT_SYMBOL_GPL(iscsi_conn_unbind);
 
 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;
     hdr->lun = task->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 age;
 
     cls_session = starget_to_session(scsi_target(sc->device));
     session = cls_session->dd_data;
 
     ISCSI_DBG_EH(session, "aborting sc %p\n", sc);
 
 completion_check:
     mutex_lock(&session->eh_mutex);
     spin_lock_bh(&session->frwd_lock);
     /*
      * if session was ISCSI_STATE_IN_RECOVERY then we may not have
      * got the command.
      */
     if (!iscsi_cmd(sc)->task) {
         ISCSI_DBG_EH(session, "sc never reached iscsi layer or "
                       "it completed.\n");
         spin_unlock_bh(&session->frwd_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 ||
         iscsi_cmd(sc)->age != session->age) {
         spin_unlock_bh(&session->frwd_lock);
         mutex_unlock(&session->eh_mutex);
         ISCSI_DBG_EH(session, "failing abort due to dropped "
                   "session.\n");
         return FAILED;
     }
 
     spin_lock(&session->back_lock);
     task = iscsi_cmd(sc)->task;
     if (!task || !task->sc) {
         /* task completed before time out */
         ISCSI_DBG_EH(session, "sc completed while abort in progress\n");
 
         spin_unlock(&session->back_lock);
         spin_unlock_bh(&session->frwd_lock);
         mutex_unlock(&session->eh_mutex);
         return SUCCESS;
     }
 
     if (!iscsi_get_task(task)) {
         spin_unlock(&session->back_lock);
         spin_unlock_bh(&session->frwd_lock);
         mutex_unlock(&session->eh_mutex);
         /* We are just about to call iscsi_free_task so wait for it. */
         udelay(ISCSI_CMD_COMPL_WAIT);
         goto completion_check;
     }
 
     ISCSI_DBG_EH(session, "aborting [sc %p itt 0x%x]\n", sc, task->itt);
     conn = session->leadconn;
     iscsi_get_conn(conn->cls_conn);
     conn->eh_abort_cnt++;
     age = session->age;
     spin_unlock(&session->back_lock);
 
     if (task->state == ISCSI_TASK_PENDING) {
         fail_scsi_task(task, DID_ABORT);
         goto success;
     }
 
     /* only have one tmf outstanding at a time */
     if (session->tmf_state != TMF_INITIAL)
         goto failed;
     session->tmf_state = TMF_QUEUED;
 
     hdr = &session->tmhdr;
     iscsi_prep_abort_task_pdu(task, hdr);
 
     if (iscsi_exec_task_mgmt_fn(conn, hdr, age, session->abort_timeout))
         goto failed;
 
     switch (session->tmf_state) {
     case TMF_SUCCESS:
         spin_unlock_bh(&session->frwd_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->frwd_lock);
         fail_scsi_task(task, DID_ABORT);
         session->tmf_state = TMF_INITIAL;
         memset(hdr, 0, sizeof(*hdr));
         spin_unlock_bh(&session->frwd_lock);
         iscsi_start_tx(conn);
         goto success_unlocked;
     case TMF_TIMEDOUT:
         session->running_aborted_task = task;
         spin_unlock_bh(&session->frwd_lock);
         iscsi_conn_failure(conn, ISCSI_ERR_SCSI_EH_SESSION_RST);
         goto failed_unlocked;
     case TMF_NOT_FOUND:
         if (iscsi_task_is_completed(task)) {
             session->tmf_state = TMF_INITIAL;
             memset(hdr, 0, sizeof(*hdr));
             /* task completed before tmf abort response */
             ISCSI_DBG_EH(session, "sc completed while abort in "
                           "progress\n");
             goto success;
         }
         fallthrough;
     default:
         session->tmf_state = TMF_INITIAL;
         goto failed;
     }
 
 success:
     spin_unlock_bh(&session->frwd_lock);
 success_unlocked:
     ISCSI_DBG_EH(session, "abort success [sc %p itt 0x%x]\n",
              sc, task->itt);
     iscsi_put_task(task);
     iscsi_put_conn(conn->cls_conn);
     mutex_unlock(&session->eh_mutex);
     return SUCCESS;
 
 failed:
     spin_unlock_bh(&session->frwd_lock);
 failed_unlocked:
     ISCSI_DBG_EH(session, "abort failed [sc %p itt 0x%x]\n", sc,
              task ? task->itt : 0);
     /*
      * The driver might be accessing the task so hold the ref. The conn
      * stop cleanup will drop the ref after ep_disconnect so we know the
      * driver's no longer touching the task.
      */
     if (!session->running_aborted_task)
         iscsi_put_task(task);
 
     iscsi_put_conn(conn->cls_conn);
     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, &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 %llu]\n", sc,
              sc->device->lun);
 
     mutex_lock(&session->eh_mutex);
     spin_lock_bh(&session->frwd_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 (session->tmf_state != TMF_INITIAL)
         goto unlock;
     session->tmf_state = TMF_QUEUED;
 
     hdr = &session->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 (session->tmf_state) {
     case TMF_SUCCESS:
         break;
     case TMF_TIMEDOUT:
         spin_unlock_bh(&session->frwd_lock);
         iscsi_conn_failure(conn, ISCSI_ERR_SCSI_EH_SESSION_RST);
         goto done;
     default:
         session->tmf_state = TMF_INITIAL;
         goto unlock;
     }
 
     rc = SUCCESS;
     spin_unlock_bh(&session->frwd_lock);
 
     iscsi_suspend_tx(conn);
 
     spin_lock_bh(&session->frwd_lock);
     memset(hdr, 0, sizeof(*hdr));
     fail_scsi_tasks(conn, sc->device->lun, DID_ERROR);
     session->tmf_state = TMF_INITIAL;
     spin_unlock_bh(&session->frwd_lock);
 
     iscsi_start_tx(conn);
     goto done;
 
 unlock:
     spin_unlock_bh(&session->frwd_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);
 
 void iscsi_session_recovery_timedout(struct iscsi_cls_session *cls_session)
 {
     struct iscsi_session *session = cls_session->dd_data;
 
     spin_lock_bh(&session->frwd_lock);
     if (session->state != ISCSI_STATE_LOGGED_IN) {
         session->state = ISCSI_STATE_RECOVERY_FAILED;
         wake_up(&session->ehwait);
     }
     spin_unlock_bh(&session->frwd_lock);
 }
 EXPORT_SYMBOL_GPL(iscsi_session_recovery_timedout);
 
 /**
  * iscsi_eh_session_reset - drop session and attempt relogin
  * @sc: scsi command
  *
  * This function will wait for a relogin, session termination from
  * userspace, or a recovery/replacement timeout.
  */
 int iscsi_eh_session_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;
 
     mutex_lock(&session->eh_mutex);
     spin_lock_bh(&session->frwd_lock);
     if (session->state == ISCSI_STATE_TERMINATE) {
 failed:
         ISCSI_DBG_EH(session,
                  "failing session reset: Could not log back into "
                  "%s [age %d]\n", session->targetname,
                  session->age);
         spin_unlock_bh(&session->frwd_lock);
         mutex_unlock(&session->eh_mutex);
         return FAILED;
     }
 
     conn = session->leadconn;
     iscsi_get_conn(conn->cls_conn);
 
     spin_unlock_bh(&session->frwd_lock);
     mutex_unlock(&session->eh_mutex);
 
     iscsi_conn_failure(conn, ISCSI_ERR_SCSI_EH_SESSION_RST);
     iscsi_put_conn(conn->cls_conn);
 
     ISCSI_DBG_EH(session, "wait for relogin\n");
     wait_event_interruptible(session->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->frwd_lock);
     if (session->state == ISCSI_STATE_LOGGED_IN) {
         ISCSI_DBG_EH(session,
                  "session reset succeeded for %s,%s\n",
                  session->targetname, conn->persistent_address);
     } else
         goto failed;
     spin_unlock_bh(&session->frwd_lock);
     mutex_unlock(&session->eh_mutex);
     return SUCCESS;
 }
 EXPORT_SYMBOL_GPL(iscsi_eh_session_reset);
 
 static void iscsi_prep_tgt_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_TARGET_WARM_RESET & ISCSI_FLAG_TM_FUNC_MASK;
     hdr->flags |= ISCSI_FLAG_CMD_FINAL;
     hdr->rtt = RESERVED_ITT;
 }
 
 /**
  * iscsi_eh_target_reset - reset target
  * @sc: scsi command
  *
  * This will attempt to send a warm target reset.
  */
 static int iscsi_eh_target_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, "tgt Reset [sc %p tgt %s]\n", sc,
              session->targetname);
 
     mutex_lock(&session->eh_mutex);
     spin_lock_bh(&session->frwd_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 (session->tmf_state != TMF_INITIAL)
         goto unlock;
     session->tmf_state = TMF_QUEUED;
 
     hdr = &session->tmhdr;
     iscsi_prep_tgt_reset_pdu(sc, hdr);
 
     if (iscsi_exec_task_mgmt_fn(conn, hdr, session->age,
                     session->tgt_reset_timeout)) {
         rc = FAILED;
         goto unlock;
     }
 
     switch (session->tmf_state) {
     case TMF_SUCCESS:
         break;
     case TMF_TIMEDOUT:
         spin_unlock_bh(&session->frwd_lock);
         iscsi_conn_failure(conn, ISCSI_ERR_SCSI_EH_SESSION_RST);
         goto done;
     default:
         session->tmf_state = TMF_INITIAL;
         goto unlock;
     }
 
     rc = SUCCESS;
     spin_unlock_bh(&session->frwd_lock);
 
     iscsi_suspend_tx(conn);
 
     spin_lock_bh(&session->frwd_lock);
     memset(hdr, 0, sizeof(*hdr));
     fail_scsi_tasks(conn, -1, DID_ERROR);
     session->tmf_state = TMF_INITIAL;
     spin_unlock_bh(&session->frwd_lock);
 
     iscsi_start_tx(conn);
     goto done;
 
 unlock:
     spin_unlock_bh(&session->frwd_lock);
 done:
     ISCSI_DBG_EH(session, "tgt %s reset result = %s\n", session->targetname,
              rc == SUCCESS ? "SUCCESS" : "FAILED");
     mutex_unlock(&session->eh_mutex);
     return rc;
 }
 
 /**
  * iscsi_eh_recover_target - reset target and possibly the session
  * @sc: scsi command
  *
  * This will attempt to send a warm target reset. If that fails,
  * we will escalate to ERL0 session recovery.
  */
 int iscsi_eh_recover_target(struct scsi_cmnd *sc)
 {
     int rc;
 
     rc = iscsi_eh_target_reset(sc);
     if (rc == FAILED)
         rc = iscsi_eh_session_reset(sc);
     return rc;
 }
 EXPORT_SYMBOL_GPL(iscsi_eh_recover_target);
 
 /*
  * 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 = kvcalloc(num_arrays * max, sizeof(void *), GFP_KERNEL);
     if (q->pool == NULL)
         return -ENOMEM;
 
     kfifo_init(&q->queue, (void*)q->pool, max * sizeof(void*));
 
     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_in(&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]);
     kvfree(q->pool);
 }
 EXPORT_SYMBOL_GPL(iscsi_pool_free);
 
 int iscsi_host_get_max_scsi_cmds(struct Scsi_Host *shost,
                  uint16_t requested_cmds_max)
 {
     int scsi_cmds, total_cmds = requested_cmds_max;
 
 check:
     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 max cmds of %d. Must be a power of two that is at least %d.\n",
                total_cmds, ISCSI_TOTAL_CMDS_MIN);
         return -EINVAL;
     }
 
     if (total_cmds > ISCSI_TOTAL_CMDS_MAX) {
         printk(KERN_INFO "iscsi: invalid max cmds of %d. Must be a power of 2 less than or equal to %d. Using %d.\n",
                requested_cmds_max, ISCSI_TOTAL_CMDS_MAX,
                ISCSI_TOTAL_CMDS_MAX);
         total_cmds = ISCSI_TOTAL_CMDS_MAX;
     }
 
     if (!is_power_of_2(total_cmds)) {
         total_cmds = rounddown_pow_of_two(total_cmds);
         if (total_cmds < ISCSI_TOTAL_CMDS_MIN) {
             printk(KERN_ERR "iscsi: invalid max cmds of %d. Must be a power of 2 greater than %d.\n", requested_cmds_max, ISCSI_TOTAL_CMDS_MIN);
             return -EINVAL;
         }
 
         printk(KERN_INFO "iscsi: invalid max cmds %d. Must be a power of 2. Rounding max cmds down to %d.\n",
                requested_cmds_max, total_cmds);
     }
 
     scsi_cmds = total_cmds - ISCSI_MGMT_CMDS_MAX;
     if (shost->can_queue && scsi_cmds > shost->can_queue) {
         total_cmds = shost->can_queue;
 
         printk(KERN_INFO "iscsi: requested max cmds %u is higher than driver limit. Using driver limit %u\n",
                requested_cmds_max, shost->can_queue);
         goto check;
     }
 
     return scsi_cmds;
 }
 EXPORT_SYMBOL_GPL(iscsi_host_get_max_scsi_cmds);
 
 /**
  * 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;
 
     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) {
         ihost->workq = alloc_workqueue("iscsi_q_%d",
             WQ_SYSFS | __WQ_LEGACY | WQ_MEM_RECLAIM | WQ_UNBOUND,
             1, shost->host_no);
         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
  * @is_shutdown: true if called from a driver shutdown callout
  *
  * If there are any sessions left, this will initiate the removal and wait
  * for the completion.
  */
 void iscsi_host_remove(struct Scsi_Host *shost, bool is_shutdown)
 {
     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);
 
     if (!is_shutdown)
         iscsi_host_for_each_session(shost, iscsi_notify_host_removed);
     else
         iscsi_host_for_each_session(shost, iscsi_force_destroy_session);
 
     wait_event_interruptible(ihost->session_removal_wq,
                  ihost->num_sessions == 0);
     if (signal_pending(current))
         flush_signals(current);
 
     scsi_remove_host(shost);
 }
 EXPORT_SYMBOL_GPL(iscsi_host_remove);
 
 void iscsi_host_free(struct Scsi_Host *shost)
 {
     struct iscsi_host *ihost = shost_priv(shost);
 
     if (ihost->workq)
         destroy_workqueue(ihost->workq);
 
     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
  * @dd_size: private driver data size, added to session allocation size
  * @cmd_task_size: LLD task private data size
  * @initial_cmdsn: initial CmdSN
  * @id: target ID to add to this session
  *
  * 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 dd_size, 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;
     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);
 
     scsi_cmds = iscsi_host_get_max_scsi_cmds(shost, cmds_max);
     if (scsi_cmds < 0)
         goto dec_session_count;
 
     cls_session = iscsi_alloc_session(shost, iscsit,
                       sizeof(struct iscsi_session) +
                       dd_size);
     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->tgt_reset_timeout = 30;
     session->lu_reset_timeout = 15;
     session->abort_timeout = 10;
     session->scsi_cmds_max = scsi_cmds;
     session->cmds_max = scsi_cmds + ISCSI_MGMT_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;
     session->dd_data = cls_session->dd_data + sizeof(*session);
 
     session->tmf_state = TMF_INITIAL;
     timer_setup(&session->tmf_timer, iscsi_tmf_timedout, 0);
     mutex_init(&session->eh_mutex);
     init_waitqueue_head(&session->ehwait);
 
     spin_lock_init(&session->frwd_lock);
     spin_lock_init(&session->back_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
  */
 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_remove_session(cls_session);
 
     iscsi_pool_free(&session->cmdpool);
     kfree(session->password);
     kfree(session->password_in);
     kfree(session->username);
     kfree(session->username_in);
     kfree(session->targetname);
     kfree(session->targetalias);
     kfree(session->initiatorname);
     kfree(session->boot_root);
     kfree(session->boot_nic);
     kfree(session->boot_target);
     kfree(session->ifacename);
     kfree(session->portal_type);
     kfree(session->discovery_parent_type);
 
     iscsi_free_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;
     int err;
 
     cls_conn = iscsi_alloc_conn(cls_session, sizeof(*conn) + dd_size,
                      conn_idx);
     if (!cls_conn)
         return NULL;
     conn = cls_conn->dd_data;
 
     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;
 
     timer_setup(&conn->transport_timer, iscsi_check_transport_timeouts, 0);
 
     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->frwd_lock);
     if (!kfifo_out(&session->cmdpool.queue,
                          (void*)&conn->login_task,
              sizeof(void*))) {
         spin_unlock_bh(&session->frwd_lock);
         goto login_task_alloc_fail;
     }
     spin_unlock_bh(&session->frwd_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;
 
     err = iscsi_add_conn(cls_conn);
     if (err)
         goto login_task_add_dev_fail;
 
     return cls_conn;
 
 login_task_add_dev_fail:
     free_pages((unsigned long) conn->data,
            get_order(ISCSI_DEF_MAX_RECV_SEG_LEN));
 
 login_task_data_alloc_fail:
     kfifo_in(&session->cmdpool.queue, (void*)&conn->login_task,
             sizeof(void*));
 login_task_alloc_fail:
     iscsi_put_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;
 
     iscsi_remove_conn(cls_conn);
 
     del_timer_sync(&conn->transport_timer);
 
     mutex_lock(&session->eh_mutex);
     spin_lock_bh(&session->frwd_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(&session->ehwait);
     }
     spin_unlock_bh(&session->frwd_lock);
 
     /* flush queued up work because we free the connection below */
     iscsi_suspend_tx(conn);
 
     spin_lock_bh(&session->frwd_lock);
     free_pages((unsigned long) conn->data,
            get_order(ISCSI_DEF_MAX_RECV_SEG_LEN));
     kfree(conn->persistent_address);
     kfree(conn->local_ipaddr);
     /* regular RX path uses back_lock */
     spin_lock_bh(&session->back_lock);
     kfifo_in(&session->cmdpool.queue, (void*)&conn->login_task,
             sizeof(void*));
     spin_unlock_bh(&session->back_lock);
     if (session->leadconn == conn)
         session->leadconn = NULL;
     spin_unlock_bh(&session->frwd_lock);
     mutex_unlock(&session->eh_mutex);
 
     iscsi_put_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->frwd_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;
         session->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->frwd_lock);
 
     iscsi_unblock_session(session->cls_session);
     wake_up(&session->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);
 
         spin_lock_bh(&session->back_lock);
         if (cleanup_queued_task(task)) {
             spin_unlock_bh(&session->back_lock);
             continue;
         }
 
         state = ISCSI_TASK_ABRT_SESS_RECOV;
         if (task->state == ISCSI_TASK_PENDING)
             state = ISCSI_TASK_COMPLETED;
         iscsi_complete_task(task, state);
         spin_unlock_bh(&session->back_lock);
     }
 }
 
 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;
     int old_stop_stage;
 
     mutex_lock(&session->eh_mutex);
     spin_lock_bh(&session->frwd_lock);
     if (conn->stop_stage == STOP_CONN_TERM) {
         spin_unlock_bh(&session->frwd_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;
     spin_unlock_bh(&session->frwd_lock);
 
     del_timer_sync(&conn->transport_timer);
     iscsi_suspend_tx(conn);
 
     spin_lock_bh(&session->frwd_lock);
     conn->c_stage = ISCSI_CONN_STOPPED;
     spin_unlock_bh(&session->frwd_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->frwd_lock);
     fail_scsi_tasks(conn, -1, DID_TRANSPORT_DISRUPTED);
     fail_mgmt_tasks(session, conn);
     memset(&session->tmhdr, 0, sizeof(session->tmhdr));
     spin_unlock_bh(&session->frwd_lock);
     mutex_unlock(&session->eh_mutex);
 }
 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->frwd_lock);
     if (is_leading)
         session->leadconn = conn;
 
     set_bit(ISCSI_CONN_FLAG_BOUND, &conn->flags);
     spin_unlock_bh(&session->frwd_lock);
 
     /*
      * The target could have reduced it's window size between logins, so
      * we have to reset max/exp cmdsn so we can see the new values.
      */
     spin_lock_bh(&session->back_lock);
     session->max_cmdsn = session->exp_cmdsn = session->cmdsn + 1;
     spin_unlock_bh(&session->back_lock);
     /*
      * Unblock xmitworker(), Login Phase will pass through.
      */
     clear_bit(ISCSI_CONN_FLAG_SUSPEND_RX, &conn->flags);
     clear_bit(ISCSI_CONN_FLAG_SUSPEND_TX, &conn->flags);
     return 0;
 }
 EXPORT_SYMBOL_GPL(iscsi_conn_bind);
 
 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;
 }
 EXPORT_SYMBOL_GPL(iscsi_switch_str_param);
 
 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;
     int val;
 
     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_TGT_RESET_TMO:
         sscanf(buf, "%d", &session->tgt_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, "%hu", &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_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_TARGET_ALIAS:
         return iscsi_switch_str_param(&session->targetalias, 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);
     case ISCSI_PARAM_BOOT_ROOT:
         return iscsi_switch_str_param(&session->boot_root, buf);
     case ISCSI_PARAM_BOOT_NIC:
         return iscsi_switch_str_param(&session->boot_nic, buf);
     case ISCSI_PARAM_BOOT_TARGET:
         return iscsi_switch_str_param(&session->boot_target, buf);
     case ISCSI_PARAM_PORTAL_TYPE:
         return iscsi_switch_str_param(&session->portal_type, buf);
     case ISCSI_PARAM_DISCOVERY_PARENT_TYPE:
         return iscsi_switch_str_param(&session->discovery_parent_type,
                           buf);
     case ISCSI_PARAM_DISCOVERY_SESS:
         sscanf(buf, "%d", &val);
         session->discovery_sess = !!val;
         break;
     case ISCSI_PARAM_LOCAL_IPADDR:
         return iscsi_switch_str_param(&conn->local_ipaddr, 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 = sysfs_emit(buf, "%d\n", session->fast_abort);
         break;
     case ISCSI_PARAM_ABORT_TMO:
         len = sysfs_emit(buf, "%d\n", session->abort_timeout);
         break;
     case ISCSI_PARAM_LU_RESET_TMO:
         len = sysfs_emit(buf, "%d\n", session->lu_reset_timeout);
         break;
     case ISCSI_PARAM_TGT_RESET_TMO:
         len = sysfs_emit(buf, "%d\n", session->tgt_reset_timeout);
         break;
     case ISCSI_PARAM_INITIAL_R2T_EN:
         len = sysfs_emit(buf, "%d\n", session->initial_r2t_en);
         break;
     case ISCSI_PARAM_MAX_R2T:
         len = sysfs_emit(buf, "%hu\n", session->max_r2t);
         break;
     case ISCSI_PARAM_IMM_DATA_EN:
         len = sysfs_emit(buf, "%d\n", session->imm_data_en);
         break;
     case ISCSI_PARAM_FIRST_BURST:
         len = sysfs_emit(buf, "%u\n", session->first_burst);
         break;
     case ISCSI_PARAM_MAX_BURST:
         len = sysfs_emit(buf, "%u\n", session->max_burst);
         break;
     case ISCSI_PARAM_PDU_INORDER_EN:
         len = sysfs_emit(buf, "%d\n", session->pdu_inorder_en);
         break;
     case ISCSI_PARAM_DATASEQ_INORDER_EN:
         len = sysfs_emit(buf, "%d\n", session->dataseq_inorder_en);
         break;
     case ISCSI_PARAM_DEF_TASKMGMT_TMO:
         len = sysfs_emit(buf, "%d\n", session->def_taskmgmt_tmo);
         break;
     case ISCSI_PARAM_ERL:
         len = sysfs_emit(buf, "%d\n", session->erl);
         break;
     case ISCSI_PARAM_TARGET_NAME:
         len = sysfs_emit(buf, "%s\n", session->targetname);
         break;
     case ISCSI_PARAM_TARGET_ALIAS:
         len = sysfs_emit(buf, "%s\n", session->targetalias);
         break;
     case ISCSI_PARAM_TPGT:
         len = sysfs_emit(buf, "%d\n", session->tpgt);
         break;
     case ISCSI_PARAM_USERNAME:
         len = sysfs_emit(buf, "%s\n", session->username);
         break;
     case ISCSI_PARAM_USERNAME_IN:
         len = sysfs_emit(buf, "%s\n", session->username_in);
         break;
     case ISCSI_PARAM_PASSWORD:
         len = sysfs_emit(buf, "%s\n", session->password);
         break;
     case ISCSI_PARAM_PASSWORD_IN:
         len = sysfs_emit(buf, "%s\n", session->password_in);
         break;
     case ISCSI_PARAM_IFACE_NAME:
         len = sysfs_emit(buf, "%s\n", session->ifacename);
         break;
     case ISCSI_PARAM_INITIATOR_NAME:
         len = sysfs_emit(buf, "%s\n", session->initiatorname);
         break;
     case ISCSI_PARAM_BOOT_ROOT:
         len = sysfs_emit(buf, "%s\n", session->boot_root);
         break;
     case ISCSI_PARAM_BOOT_NIC:
         len = sysfs_emit(buf, "%s\n", session->boot_nic);
         break;
     case ISCSI_PARAM_BOOT_TARGET:
         len = sysfs_emit(buf, "%s\n", session->boot_target);
         break;
     case ISCSI_PARAM_AUTO_SND_TGT_DISABLE:
         len = sysfs_emit(buf, "%u\n", session->auto_snd_tgt_disable);
         break;
     case ISCSI_PARAM_DISCOVERY_SESS:
         len = sysfs_emit(buf, "%u\n", session->discovery_sess);
         break;
     case ISCSI_PARAM_PORTAL_TYPE:
         len = sysfs_emit(buf, "%s\n", session->portal_type);
         break;
     case ISCSI_PARAM_CHAP_AUTH_EN:
         len = sysfs_emit(buf, "%u\n", session->chap_auth_en);
         break;
     case ISCSI_PARAM_DISCOVERY_LOGOUT_EN:
         len = sysfs_emit(buf, "%u\n", session->discovery_logout_en);
         break;
     case ISCSI_PARAM_BIDI_CHAP_EN:
         len = sysfs_emit(buf, "%u\n", session->bidi_chap_en);
         break;
     case ISCSI_PARAM_DISCOVERY_AUTH_OPTIONAL:
         len = sysfs_emit(buf, "%u\n", session->discovery_auth_optional);
         break;
     case ISCSI_PARAM_DEF_TIME2WAIT:
         len = sysfs_emit(buf, "%d\n", session->time2wait);
         break;
     case ISCSI_PARAM_DEF_TIME2RETAIN:
         len = sysfs_emit(buf, "%d\n", session->time2retain);
         break;
     case ISCSI_PARAM_TSID:
         len = sysfs_emit(buf, "%u\n", session->tsid);
         break;
     case ISCSI_PARAM_ISID:
         len = sysfs_emit(buf, "%02x%02x%02x%02x%02x%02x\n",
                   session->isid[0], session->isid[1],
                   session->isid[2], session->isid[3],
                   session->isid[4], session->isid[5]);
         break;
     case ISCSI_PARAM_DISCOVERY_PARENT_IDX:
         len = sysfs_emit(buf, "%u\n", session->discovery_parent_idx);
         break;
     case ISCSI_PARAM_DISCOVERY_PARENT_TYPE:
         if (session->discovery_parent_type)
             len = sysfs_emit(buf, "%s\n",
                       session->discovery_parent_type);
         else
             len = sysfs_emit(buf, "\n");
         break;
     default:
         return -ENOSYS;
     }
 
     return len;
 }
 EXPORT_SYMBOL_GPL(iscsi_session_get_param);
 
 int iscsi_conn_get_addr_param(struct sockaddr_storage *addr,
                   enum iscsi_param param, char *buf)
 {
     struct sockaddr_in6 *sin6 = NULL;
     struct sockaddr_in *sin = NULL;
     int len;
 
     switch (addr->ss_family) {
     case AF_INET:
         sin = (struct sockaddr_in *)addr;
         break;
     case AF_INET6:
         sin6 = (struct sockaddr_in6 *)addr;
         break;
     default:
         return -EINVAL;
     }
 
     switch (param) {
     case ISCSI_PARAM_CONN_ADDRESS:
     case ISCSI_HOST_PARAM_IPADDRESS:
         if (sin)
             len = sysfs_emit(buf, "%pI4\n", &sin->sin_addr.s_addr);
         else
             len = sysfs_emit(buf, "%pI6\n", &sin6->sin6_addr);
         break;
     case ISCSI_PARAM_CONN_PORT:
     case ISCSI_PARAM_LOCAL_PORT:
         if (sin)
             len = sysfs_emit(buf, "%hu\n", be16_to_cpu(sin->sin_port));
         else
             len = sysfs_emit(buf, "%hu\n",
                       be16_to_cpu(sin6->sin6_port));
         break;
     default:
         return -EINVAL;
     }
 
     return len;
 }
 EXPORT_SYMBOL_GPL(iscsi_conn_get_addr_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 = sysfs_emit(buf, "%u\n", conn->ping_timeout);
         break;
     case ISCSI_PARAM_RECV_TMO:
         len = sysfs_emit(buf, "%u\n", conn->recv_timeout);
         break;
     case ISCSI_PARAM_MAX_RECV_DLENGTH:
         len = sysfs_emit(buf, "%u\n", conn->max_recv_dlength);
         break;
     case ISCSI_PARAM_MAX_XMIT_DLENGTH:
         len = sysfs_emit(buf, "%u\n", conn->max_xmit_dlength);
         break;
     case ISCSI_PARAM_HDRDGST_EN:
         len = sysfs_emit(buf, "%d\n", conn->hdrdgst_en);
         break;
     case ISCSI_PARAM_DATADGST_EN:
         len = sysfs_emit(buf, "%d\n", conn->datadgst_en);
         break;
     case ISCSI_PARAM_IFMARKER_EN:
         len = sysfs_emit(buf, "%d\n", conn->ifmarker_en);
         break;
     case ISCSI_PARAM_OFMARKER_EN:
         len = sysfs_emit(buf, "%d\n", conn->ofmarker_en);
         break;
     case ISCSI_PARAM_EXP_STATSN:
         len = sysfs_emit(buf, "%u\n", conn->exp_statsn);
         break;
     case ISCSI_PARAM_PERSISTENT_PORT:
         len = sysfs_emit(buf, "%d\n", conn->persistent_port);
         break;
     case ISCSI_PARAM_PERSISTENT_ADDRESS:
         len = sysfs_emit(buf, "%s\n", conn->persistent_address);
         break;
     case ISCSI_PARAM_STATSN:
         len = sysfs_emit(buf, "%u\n", conn->statsn);
         break;
     case ISCSI_PARAM_MAX_SEGMENT_SIZE:
         len = sysfs_emit(buf, "%u\n", conn->max_segment_size);
         break;
     case ISCSI_PARAM_KEEPALIVE_TMO:
         len = sysfs_emit(buf, "%u\n", conn->keepalive_tmo);
         break;
     case ISCSI_PARAM_LOCAL_PORT:
         len = sysfs_emit(buf, "%u\n", conn->local_port);
         break;
     case ISCSI_PARAM_TCP_TIMESTAMP_STAT:
         len = sysfs_emit(buf, "%u\n", conn->tcp_timestamp_stat);
         break;
     case ISCSI_PARAM_TCP_NAGLE_DISABLE:
         len = sysfs_emit(buf, "%u\n", conn->tcp_nagle_disable);
         break;
     case ISCSI_PARAM_TCP_WSF_DISABLE:
         len = sysfs_emit(buf, "%u\n", conn->tcp_wsf_disable);
         break;
     case ISCSI_PARAM_TCP_TIMER_SCALE:
         len = sysfs_emit(buf, "%u\n", conn->tcp_timer_scale);
         break;
     case ISCSI_PARAM_TCP_TIMESTAMP_EN:
         len = sysfs_emit(buf, "%u\n", conn->tcp_timestamp_en);
         break;
     case ISCSI_PARAM_IP_FRAGMENT_DISABLE:
         len = sysfs_emit(buf, "%u\n", conn->fragment_disable);
         break;
     case ISCSI_PARAM_IPV4_TOS:
         len = sysfs_emit(buf, "%u\n", conn->ipv4_tos);
         break;
     case ISCSI_PARAM_IPV6_TC:
         len = sysfs_emit(buf, "%u\n", conn->ipv6_traffic_class);
         break;
     case ISCSI_PARAM_IPV6_FLOW_LABEL:
         len = sysfs_emit(buf, "%u\n", conn->ipv6_flow_label);
         break;
     case ISCSI_PARAM_IS_FW_ASSIGNED_IPV6:
         len = sysfs_emit(buf, "%u\n", conn->is_fw_assigned_ipv6);
         break;
     case ISCSI_PARAM_TCP_XMIT_WSF:
         len = sysfs_emit(buf, "%u\n", conn->tcp_xmit_wsf);
         break;
     case ISCSI_PARAM_TCP_RECV_WSF:
         len = sysfs_emit(buf, "%u\n", conn->tcp_recv_wsf);
         break;
     case ISCSI_PARAM_LOCAL_IPADDR:
         len = sysfs_emit(buf, "%s\n", conn->local_ipaddr);
         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 = sysfs_emit(buf, "%s\n", ihost->netdev);
         break;
     case ISCSI_HOST_PARAM_HWADDRESS:
         len = sysfs_emit(buf, "%s\n", ihost->hwaddress);
         break;
     case ISCSI_HOST_PARAM_INITIATOR_NAME:
         len = sysfs_emit(buf, "%s\n", ihost->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_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");