Adding upstream version 5.10.209.upstream/5.10.209upstream

Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>

1 files changed, 3679 insertions, 0 deletions

diff --git a/drivers/scsi/libiscsi.c b/drivers/scsi/libiscsi.c
new file mode 100644
index 000000000..05799b419
--- /dev/null
+++ b/drivers/scsi/libiscsi.c
@@ -0,0 +1,3679 @@
+// 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);
+
+inline void iscsi_conn_queue_work(struct iscsi_conn *conn)
+{
+	struct Scsi_Host *shost = conn->session->host;
+	struct iscsi_host *ihost = shost_priv(shost);
+
+	if (ihost->workq)
+		queue_work(ihost->workq, &conn->xmitwork);
+}
+EXPORT_SYMBOL_GPL(iscsi_conn_queue_work);
+
+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 */
+		sc->SCp.ptr = 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)
+			sc->scsi_done(sc);
+	}
+}
+
+void __iscsi_get_task(struct iscsi_task *task)
+{
+	refcount_inc(&task->refcount);
+}
+EXPORT_SYMBOL_GPL(__iscsi_get_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;
+
+	/* regular RX path uses back_lock */
+	spin_lock_bh(&session->back_lock);
+	__iscsi_put_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;
+
+	spin_lock_bh(&conn->taskqueuelock);
+	if (!list_empty(&task->running)) {
+		pr_debug_once("%s while task on list", __func__);
+		list_del_init(&task->running);
+	}
+	spin_unlock_bh(&conn->taskqueuelock);
+
+	if (conn->task == task)
+		conn->task = NULL;
+
+	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);
+
+
+/*
+ * session back_lock must be held and if not called for a task that is
+ * still pending or from the xmit thread, then xmit thread must
+ * be suspended.
+ */
+static void fail_scsi_task(struct iscsi_task *task, int err)
+{
+	struct iscsi_conn *conn = task->conn;
+	struct scsi_cmnd *sc;
+	int state;
+
+	/*
+	 * if a command completes and we get a successful tmf response
+	 * we will hit this because the scsi eh abort code does not take
+	 * a ref to the task.
+	 */
+	sc = task->sc;
+	if (!sc)
+		return;
+
+	if (task->state == ISCSI_TASK_PENDING) {
+		/*
+		 * cmd never made it to the xmit thread, so we should not count
+		 * the cmd in the sequencing
+		 */
+		conn->session->queued_cmdsn--;
+		/* it was never sent so just complete like normal */
+		state = ISCSI_TASK_COMPLETED;
+	} else if (err == DID_TRANSPORT_DISRUPTED)
+		state = ISCSI_TASK_ABRT_SESS_RECOV;
+	else
+		state = ISCSI_TASK_ABRT_TMF;
+
+	sc->result = err << 16;
+	scsi_set_resid(sc, scsi_bufflen(sc));
+
+	/* regular RX path uses back_lock */
+	spin_lock_bh(&conn->session->back_lock);
+	iscsi_complete_task(task, state);
+	spin_unlock_bh(&conn->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;
+}
+
+static struct iscsi_task *
+__iscsi_conn_send_pdu(struct iscsi_conn *conn, struct iscsi_hdr *hdr,
+		      char *data, uint32_t data_size)
+{
+	struct iscsi_session *session = conn->session;
+	struct iscsi_host *ihost = shost_priv(session->host);
+	uint8_t opcode = hdr->opcode & ISCSI_OPCODE_MASK;
+	struct iscsi_task *task;
+	itt_t itt;
+
+	if (session->state == ISCSI_STATE_TERMINATE)
+		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);
+	}
+
+	if (unlikely(READ_ONCE(conn->ping_task) == INVALID_SCSI_TASK))
+		WRITE_ONCE(conn->ping_task, task);
+
+	if (!ihost->workq) {
+		if (iscsi_prep_mgmt_task(conn, task))
+			goto free_task;
+
+		if (session->tt->xmit_task(task))
+			goto free_task;
+	} else {
+		spin_lock_bh(&conn->taskqueuelock);
+		list_add_tail(&task->running, &conn->mgmtqueue);
+		spin_unlock_bh(&conn->taskqueuelock);
+		iscsi_conn_queue_work(conn);
+	}
+
+	return task;
+
+free_task:
+	/* regular RX path uses back_lock */
+	spin_lock(&session->back_lock);
+	__iscsi_put_task(task);
+	spin_unlock(&session->back_lock);
+	return NULL;
+}
+
+int iscsi_conn_send_pdu(struct iscsi_cls_conn *cls_conn, struct iscsi_hdr *hdr,
+			char *data, uint32_t data_size)
+{
+	struct iscsi_conn *conn = cls_conn->dd_data;
+	struct iscsi_session *session = conn->session;
+	int err = 0;
+
+	spin_lock_bh(&session->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_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) {
+			sc->result = DRIVER_SENSE << 24 |
+				     SAM_STAT_CHECK_CONDITION;
+			scsi_build_sense_buffer(1, sc->sense_buffer,
+						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;
+		WRITE_ONCE(conn->ping_task, INVALID_SCSI_TASK);
+	}
+
+	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_conn_send_pdu(conn, (struct iscsi_hdr *)&hdr, NULL, 0);
+	if (!task) {
+		if (!rhdr)
+			WRITE_ONCE(conn->ping_task, NULL);
+		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 (task->sc->SCp.phase != conn->session->age) {
+		iscsi_session_printk(KERN_ERR, conn->session,
+				  "task's session age %d, expected %d\n",
+				  task->sc->SCp.phase, conn->session->age);
+		return NULL;
+	}
+
+	return task;
+}
+EXPORT_SYMBOL_GPL(iscsi_itt_to_ctask);
+
+void iscsi_session_failure(struct iscsi_session *session,
+			   enum iscsi_err err)
+{
+	struct iscsi_conn *conn;
+
+	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_SUSPEND_BIT, &conn->suspend_tx);
+	set_bit(ISCSI_SUSPEND_BIT, &conn->suspend_rx);
+	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 = conn->task;
+	int rc;
+
+	if (test_bit(ISCSI_SUSPEND_BIT, &conn->suspend_tx))
+		return -ENODATA;
+
+	spin_lock_bh(&conn->session->back_lock);
+	if (conn->task == NULL) {
+		spin_unlock_bh(&conn->session->back_lock);
+		return -ENODATA;
+	}
+	__iscsi_get_task(task);
+	spin_unlock_bh(&conn->session->back_lock);
+	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;
+		conn->task = NULL;
+	}
+	/* regular RX path uses back_lock */
+	spin_lock(&conn->session->back_lock);
+	__iscsi_put_task(task);
+	spin_unlock(&conn->session->back_lock);
+	return rc;
+}
+
+/**
+ * iscsi_requeue_task - requeue task to run from session workqueue
+ * @task: task to requeue
+ *
+ * LLDs that need to run a task from the session workqueue should call
+ * this. The session frwd_lock must be held. This should only be called
+ * by software drivers.
+ */
+void iscsi_requeue_task(struct iscsi_task *task)
+{
+	struct iscsi_conn *conn = task->conn;
+
+	/*
+	 * this may be on the requeue list already if the xmit_task callout
+	 * is handling the r2ts while we are adding new ones
+	 */
+	spin_lock_bh(&conn->taskqueuelock);
+	if (list_empty(&task->running))
+		list_add_tail(&task->running, &conn->requeue);
+	spin_unlock_bh(&conn->taskqueuelock);
+	iscsi_conn_queue_work(conn);
+}
+EXPORT_SYMBOL_GPL(iscsi_requeue_task);
+
+/**
+ * iscsi_data_xmit - xmit any command into the scheduled connection
+ * @conn: iscsi connection
+ *
+ * Notes:
+ *	The function can return -EAGAIN in which case the caller must
+ *	re-schedule it again later or recover. '0' return code means
+ *	successful xmit.
+ **/
+static int iscsi_data_xmit(struct iscsi_conn *conn)
+{
+	struct iscsi_task *task;
+	int rc = 0;
+
+	spin_lock_bh(&conn->session->frwd_lock);
+	if (test_bit(ISCSI_SUSPEND_BIT, &conn->suspend_tx)) {
+		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);
+	        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
+	 */
+	spin_lock_bh(&conn->taskqueuelock);
+check_mgmt:
+	while (!list_empty(&conn->mgmtqueue)) {
+		conn->task = list_entry(conn->mgmtqueue.next,
+					 struct iscsi_task, running);
+		list_del_init(&conn->task->running);
+		spin_unlock_bh(&conn->taskqueuelock);
+		if (iscsi_prep_mgmt_task(conn, conn->task)) {
+			/* regular RX path uses back_lock */
+			spin_lock_bh(&conn->session->back_lock);
+			__iscsi_put_task(conn->task);
+			spin_unlock_bh(&conn->session->back_lock);
+			conn->task = NULL;
+			spin_lock_bh(&conn->taskqueuelock);
+			continue;
+		}
+		rc = iscsi_xmit_task(conn);
+		if (rc)
+			goto done;
+		spin_lock_bh(&conn->taskqueuelock);
+	}
+
+	/* process pending command queue */
+	while (!list_empty(&conn->cmdqueue)) {
+		conn->task = list_entry(conn->cmdqueue.next, struct iscsi_task,
+					running);
+		list_del_init(&conn->task->running);
+		spin_unlock_bh(&conn->taskqueuelock);
+		if (conn->session->state == ISCSI_STATE_LOGGING_OUT) {
+			fail_scsi_task(conn->task, DID_IMM_RETRY);
+			spin_lock_bh(&conn->taskqueuelock);
+			continue;
+		}
+		rc = iscsi_prep_scsi_cmd_pdu(conn->task);
+		if (rc) {
+			if (rc == -ENOMEM || rc == -EACCES)
+				fail_scsi_task(conn->task, DID_IMM_RETRY);
+			else
+				fail_scsi_task(conn->task, DID_ABORT);
+			spin_lock_bh(&conn->taskqueuelock);
+			continue;
+		}
+		rc = iscsi_xmit_task(conn);
+		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
+		 */
+		spin_lock_bh(&conn->taskqueuelock);
+		if (!list_empty(&conn->mgmtqueue))
+			goto check_mgmt;
+	}
+
+	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;
+
+		conn->task = task;
+		list_del_init(&conn->task->running);
+		conn->task->state = ISCSI_TASK_RUNNING;
+		spin_unlock_bh(&conn->taskqueuelock);
+		rc = iscsi_xmit_task(conn);
+		if (rc)
+			goto done;
+		spin_lock_bh(&conn->taskqueuelock);
+		if (!list_empty(&conn->mgmtqueue))
+			goto check_mgmt;
+	}
+	spin_unlock_bh(&conn->taskqueuelock);
+	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;
+
+	sc->SCp.phase = conn->session->age;
+	sc->SCp.ptr = (char *) 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;
+	sc->SCp.ptr = 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_SUSPEND_BIT, &conn->suspend_tx)) {
+		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 {
+		spin_lock_bh(&conn->taskqueuelock);
+		list_add_tail(&task->running, &conn->cmdqueue);
+		spin_unlock_bh(&conn->taskqueuelock);
+		iscsi_conn_queue_work(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));
+	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;
+	struct iscsi_task *task;
+
+	task = __iscsi_conn_send_pdu(conn, (struct iscsi_hdr *)hdr,
+				      NULL, 0);
+	if (!task) {
+		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 lock held and recv side suspended and xmit
+ * thread flushed
+ */
+static void fail_scsi_tasks(struct iscsi_conn *conn, u64 lun, int error)
+{
+	struct iscsi_task *task;
+	int i;
+
+	for (i = 0; i < conn->session->cmds_max; i++) {
+		task = conn->session->cmds[i];
+		if (!task->sc || task->state == ISCSI_TASK_FREE)
+			continue;
+
+		if (lun != -1 && lun != task->sc->device->lun)
+			continue;
+
+		ISCSI_DBG_SESSION(conn->session,
+				  "failing sc %p itt 0x%x state %d\n",
+				  task->sc, task->itt, task->state);
+		fail_scsi_task(task, error);
+	}
+}
+
+/**
+ * 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_SUSPEND_BIT, &conn->suspend_tx);
+	spin_unlock_bh(&conn->session->frwd_lock);
+}
+EXPORT_SYMBOL_GPL(iscsi_suspend_queue);
+
+/**
+ * iscsi_suspend_tx - suspend iscsi_data_xmit
+ * @conn: iscsi conn tp 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_SUSPEND_BIT, &conn->suspend_tx);
+	if (ihost->workq)
+		flush_workqueue(ihost->workq);
+}
+EXPORT_SYMBOL_GPL(iscsi_suspend_tx);
+
+static void iscsi_start_tx(struct iscsi_conn *conn)
+{
+	clear_bit(ISCSI_SUSPEND_BIT, &conn->suspend_tx);
+	iscsi_conn_queue_work(conn);
+}
+
+/*
+ * We want to make sure a ping is in flight. It has timed out.
+ * And we are not busy processing a pdu that is making
+ * progress but got started before the ping and is taking a while
+ * to complete so the ping is just stuck behind it in a queue.
+ */
+static int iscsi_has_ping_timed_out(struct iscsi_conn *conn)
+{
+	if (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);
+	task = (struct iscsi_task *)sc->SCp.ptr;
+	if (!task) {
+		/*
+		 * Raced with completion. Blk layer has taken ownership
+		 * so let timeout code complete it now.
+		 */
+		rc = BLK_EH_DONE;
+		goto done;
+	}
+
+	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;
+	}
+
+	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);
+			rc = BLK_EH_RESET_TIMER;
+			goto done;
+		}
+	}
+
+	/* Assumes nop timeout is shorter than scsi cmd timeout */
+	if (task->have_checked_conn)
+		goto done;
+
+	/*
+	 * Checking the transport already or nop from a cmd timeout still
+	 * running
+	 */
+	if (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:
+	if (task)
+		task->last_timeout = jiffies;
+	spin_unlock_bh(&session->frwd_lock);
+	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);
+	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);
+
+	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 (!sc->SCp.ptr) {
+		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 ||
+	    sc->SCp.phase != 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;
+	}
+
+	conn = session->leadconn;
+	conn->eh_abort_cnt++;
+	age = session->age;
+
+	task = (struct iscsi_task *)sc->SCp.ptr;
+	ISCSI_DBG_EH(session, "aborting [sc %p itt 0x%x]\n",
+		     sc, task->itt);
+
+	/* task completed before time out */
+	if (!task->sc) {
+		ISCSI_DBG_EH(session, "sc completed while abort in progress\n");
+		goto success;
+	}
+
+	if (task->state == ISCSI_TASK_PENDING) {
+		fail_scsi_task(task, DID_ABORT);
+		goto success;
+	}
+
+	/* only have one tmf outstanding at a time */
+	if (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:
+		spin_unlock_bh(&session->frwd_lock);
+		iscsi_conn_failure(conn, ISCSI_ERR_SCSI_EH_SESSION_RST);
+		goto failed_unlocked;
+	case TMF_NOT_FOUND:
+		if (!sc->SCp.ptr) {
+			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);
+	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);
+	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;
+	conn = session->leadconn;
+
+	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;
+	}
+
+	spin_unlock_bh(&session->frwd_lock);
+	mutex_unlock(&session->eh_mutex);
+	/*
+	 * we drop the lock here but the leadconn cannot be destoyed while
+	 * we are in the scsi eh
+	 */
+	iscsi_conn_failure(conn, ISCSI_ERR_SCSI_EH_SESSION_RST);
+
+	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);
+
+/**
+ * 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) {
+		snprintf(ihost->workq_name, sizeof(ihost->workq_name),
+			"iscsi_q_%d", shost->host_no);
+		ihost->workq = alloc_workqueue("%s",
+			WQ_SYSFS | __WQ_LEGACY | WQ_MEM_RECLAIM | WQ_UNBOUND,
+			1, ihost->workq_name);
+		if (!ihost->workq)
+			goto free_host;
+	}
+
+	spin_lock_init(&ihost->lock);
+	ihost->state = ISCSI_HOST_SETUP;
+	ihost->num_sessions = 0;
+	init_waitqueue_head(&ihost->session_removal_wq);
+	return shost;
+
+free_host:
+	scsi_host_put(shost);
+	return NULL;
+}
+EXPORT_SYMBOL_GPL(iscsi_host_alloc);
+
+static void iscsi_notify_host_removed(struct iscsi_cls_session *cls_session)
+{
+	iscsi_session_failure(cls_session->dd_data, ISCSI_ERR_INVALID_HOST);
+}
+
+/**
+ * iscsi_host_remove - remove host and sessions
+ * @shost: scsi host
+ *
+ * If there are any sessions left, this will initiate the removal and wait
+ * for the completion.
+ */
+void iscsi_host_remove(struct Scsi_Host *shost)
+{
+	struct iscsi_host *ihost = shost_priv(shost);
+	unsigned long flags;
+
+	spin_lock_irqsave(&ihost->lock, flags);
+	ihost->state = ISCSI_HOST_REMOVED;
+	spin_unlock_irqrestore(&ihost->lock, flags);
+
+	iscsi_host_for_each_session(shost, iscsi_notify_host_removed);
+	wait_event_interruptible(ihost->session_removal_wq,
+				 ihost->num_sessions == 0);
+	if (signal_pending(current))
+		flush_signals(current);
+
+	scsi_remove_host(shost);
+	if (ihost->workq)
+		destroy_workqueue(ihost->workq);
+}
+EXPORT_SYMBOL_GPL(iscsi_host_remove);
+
+void iscsi_host_free(struct Scsi_Host *shost)
+{
+	struct iscsi_host *ihost = shost_priv(shost);
+
+	kfree(ihost->netdev);
+	kfree(ihost->hwaddress);
+	kfree(ihost->initiatorname);
+	scsi_host_put(shost);
+}
+EXPORT_SYMBOL_GPL(iscsi_host_free);
+
+static void iscsi_host_dec_session_cnt(struct Scsi_Host *shost)
+{
+	struct iscsi_host *ihost = shost_priv(shost);
+	unsigned long flags;
+
+	shost = scsi_host_get(shost);
+	if (!shost) {
+		printk(KERN_ERR "Invalid state. Cannot notify host removal "
+		      "of session teardown event because host already "
+		      "removed.\n");
+		return;
+	}
+
+	spin_lock_irqsave(&ihost->lock, flags);
+	ihost->num_sessions--;
+	if (ihost->num_sessions == 0)
+		wake_up(&ihost->session_removal_wq);
+	spin_unlock_irqrestore(&ihost->lock, flags);
+	scsi_host_put(shost);
+}
+
+/**
+ * iscsi_session_setup - create iscsi cls session and host and session
+ * @iscsit: iscsi transport template
+ * @shost: scsi host
+ * @cmds_max: session can queue
+ * @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, total_cmds = cmds_max;
+	unsigned long flags;
+
+	spin_lock_irqsave(&ihost->lock, flags);
+	if (ihost->state == ISCSI_HOST_REMOVED) {
+		spin_unlock_irqrestore(&ihost->lock, flags);
+		return NULL;
+	}
+	ihost->num_sessions++;
+	spin_unlock_irqrestore(&ihost->lock, flags);
+
+	if (!total_cmds)
+		total_cmds = ISCSI_DEF_XMIT_CMDS_MAX;
+	/*
+	 * The iscsi layer needs some tasks for nop handling and tmfs,
+	 * so the cmds_max must at least be greater than ISCSI_MGMT_CMDS_MAX
+	 * + 1 command for scsi IO.
+	 */
+	if (total_cmds < ISCSI_TOTAL_CMDS_MIN) {
+		printk(KERN_ERR "iscsi: invalid can_queue of %d. can_queue "
+		       "must be a power of two that is at least %d.\n",
+		       total_cmds, ISCSI_TOTAL_CMDS_MIN);
+		goto dec_session_count;
+	}
+
+	if (total_cmds > ISCSI_TOTAL_CMDS_MAX) {
+		printk(KERN_ERR "iscsi: invalid can_queue of %d. can_queue "
+		       "must be a power of 2 less than or equal to %d.\n",
+		       cmds_max, ISCSI_TOTAL_CMDS_MAX);
+		total_cmds = ISCSI_TOTAL_CMDS_MAX;
+	}
+
+	if (!is_power_of_2(total_cmds)) {
+		printk(KERN_ERR "iscsi: invalid can_queue of %d. can_queue "
+		       "must be a power of 2.\n", total_cmds);
+		total_cmds = rounddown_pow_of_two(total_cmds);
+		if (total_cmds < ISCSI_TOTAL_CMDS_MIN)
+			goto dec_session_count;
+		printk(KERN_INFO "iscsi: Rounding can_queue to %d.\n",
+		       total_cmds);
+	}
+	scsi_cmds = total_cmds - ISCSI_MGMT_CMDS_MAX;
+
+	cls_session = iscsi_alloc_session(shost, iscsit,
+					  sizeof(struct iscsi_session) +
+					  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 = total_cmds;
+	session->queued_cmdsn = session->cmdsn = initial_cmdsn;
+	session->exp_cmdsn = initial_cmdsn + 1;
+	session->max_cmdsn = initial_cmdsn + 1;
+	session->max_r2t = 1;
+	session->tt = iscsit;
+	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);
+
+	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_pool_free(&session->cmdpool);
+
+	iscsi_remove_session(cls_session);
+
+	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;
+
+	cls_conn = iscsi_create_conn(cls_session, sizeof(*conn) + dd_size,
+				     conn_idx);
+	if (!cls_conn)
+		return NULL;
+	conn = cls_conn->dd_data;
+	memset(conn, 0, sizeof(*conn) + dd_size);
+
+	conn->dd_data = cls_conn->dd_data + sizeof(*conn);
+	conn->session = session;
+	conn->cls_conn = cls_conn;
+	conn->c_stage = ISCSI_CONN_INITIAL_STAGE;
+	conn->id = conn_idx;
+	conn->exp_statsn = 0;
+
+	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);
+	spin_lock_init(&conn->taskqueuelock);
+	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;
+
+	init_waitqueue_head(&session->ehwait);
+
+	return cls_conn;
+
+login_task_data_alloc_fail:
+	kfifo_in(&session->cmdpool.queue, (void*)&conn->login_task,
+		    sizeof(void*));
+login_task_alloc_fail:
+	iscsi_destroy_conn(cls_conn);
+	return NULL;
+}
+EXPORT_SYMBOL_GPL(iscsi_conn_setup);
+
+/**
+ * iscsi_conn_teardown - teardown iscsi connection
+ * @cls_conn: iscsi class connection
+ *
+ * TODO: we may need to make this into a two step process
+ * like scsi-mls remove + put host
+ */
+void iscsi_conn_teardown(struct iscsi_cls_conn *cls_conn)
+{
+	struct iscsi_conn *conn = cls_conn->dd_data;
+	struct iscsi_session *session = conn->session;
+	char *tmp_persistent_address = conn->persistent_address;
+	char *tmp_local_ipaddr = conn->local_ipaddr;
+
+	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));
+	/* 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_destroy_conn(cls_conn);
+	kfree(tmp_persistent_address);
+	kfree(tmp_local_ipaddr);
+}
+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);
+		state = ISCSI_TASK_ABRT_SESS_RECOV;
+		if (task->state == ISCSI_TASK_PENDING)
+			state = ISCSI_TASK_COMPLETED;
+		spin_lock_bh(&session->back_lock);
+		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;
+	spin_unlock_bh(&session->frwd_lock);
+
+	/*
+	 * Unblock xmitworker(), Login Phase will pass through.
+	 */
+	clear_bit(ISCSI_SUSPEND_BIT, &conn->suspend_rx);
+	clear_bit(ISCSI_SUSPEND_BIT, &conn->suspend_tx);
+	return 0;
+}
+EXPORT_SYMBOL_GPL(iscsi_conn_bind);
+
+int iscsi_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");