[SCSI] iscsi: add libiscsi

There is a lot of code duplcited between iscsi_tcp
and the upcoming iscsi_iser driver. This patch puts
the duplicated code in a lib. There is more code
to move around but this takes care of the
basics. For iscsi_offload if they use the lib we will
probably move some things around. For example in the
queuecommand we will not assume that the LLD wants
to do queue_work, but it is better to handle that
later when we know for sure what iscsi_offload looks
like (we could probably do this for iscsi_iser though to).

Ideally I would like to get the iscsi_transports modules
to a place where all they really have to do is put data
on the wire, but how to do that will hopefully be more clear
when we see other modules like iscsi_offload. Or maybe
iscsi_offload will not use the lib and it will just be
iscsi_iser and iscsi_tcp and maybe the iscsi_tcp_tgt if that
is allowed in mainline.

Signed-off-by: Mike Christie <michaelc@cs.wisc.edu>
Signed-off-by: James Bottomley <James.Bottomley@SteelEye.com>

1 files changed, 1697 insertions, 0 deletions

diff --git a/drivers/scsi/libiscsi.c b/drivers/scsi/libiscsi.c
new file mode 100644
index 000000000000..274a1374ab64
--- /dev/null
+++ b/drivers/scsi/libiscsi.c
@@ -0,0 +1,1697 @@
+/*
+ * iSCSI lib functions
+ *
+ * Copyright (C) 2006 Red Hat, Inc.  All rights reserved.
+ * Copyright (C) 2004 - 2006 Mike Christie
+ * Copyright (C) 2004 - 2005 Dmitry Yusupov
+ * Copyright (C) 2004 - 2005 Alex Aizman
+ * maintained by open-iscsi@googlegroups.com
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software
+ * Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
+ */
+#include <linux/types.h>
+#include <linux/mutex.h>
+#include <linux/kfifo.h>
+#include <linux/delay.h>
+#include <net/tcp.h>
+#include <scsi/scsi_cmnd.h>
+#include <scsi/scsi_device.h>
+#include <scsi/scsi_eh.h>
+#include <scsi/scsi_tcq.h>
+#include <scsi/scsi_host.h>
+#include <scsi/scsi.h>
+#include <scsi/iscsi_proto.h>
+#include <scsi/scsi_transport.h>
+#include <scsi/scsi_transport_iscsi.h>
+#include <scsi/libiscsi.h>
+
+struct iscsi_session *
+class_to_transport_session(struct iscsi_cls_session *cls_session)
+{
+	struct Scsi_Host *shost = iscsi_session_to_shost(cls_session);
+	return iscsi_hostdata(shost->hostdata);
+}
+EXPORT_SYMBOL_GPL(class_to_transport_session);
+
+#define INVALID_SN_DELTA	0xffff
+
+int
+iscsi_check_assign_cmdsn(struct iscsi_session *session, struct iscsi_nopin *hdr)
+{
+	uint32_t max_cmdsn = be32_to_cpu(hdr->max_cmdsn);
+	uint32_t exp_cmdsn = be32_to_cpu(hdr->exp_cmdsn);
+
+	if (max_cmdsn < exp_cmdsn -1 &&
+	    max_cmdsn > exp_cmdsn - INVALID_SN_DELTA)
+		return ISCSI_ERR_MAX_CMDSN;
+	if (max_cmdsn > session->max_cmdsn ||
+	    max_cmdsn < session->max_cmdsn - INVALID_SN_DELTA)
+		session->max_cmdsn = max_cmdsn;
+	if (exp_cmdsn > session->exp_cmdsn ||
+	    exp_cmdsn < session->exp_cmdsn - INVALID_SN_DELTA)
+		session->exp_cmdsn = exp_cmdsn;
+
+	return 0;
+}
+EXPORT_SYMBOL_GPL(iscsi_check_assign_cmdsn);
+
+void iscsi_prep_unsolicit_data_pdu(struct iscsi_cmd_task *ctask,
+				   struct iscsi_data *hdr,
+				   int transport_data_cnt)
+{
+	struct iscsi_conn *conn = ctask->conn;
+
+	memset(hdr, 0, sizeof(struct iscsi_data));
+	hdr->ttt = cpu_to_be32(ISCSI_RESERVED_TAG);
+	hdr->datasn = cpu_to_be32(ctask->unsol_datasn);
+	ctask->unsol_datasn++;
+	hdr->opcode = ISCSI_OP_SCSI_DATA_OUT;
+	memcpy(hdr->lun, ctask->hdr->lun, sizeof(hdr->lun));
+
+	hdr->itt = ctask->hdr->itt;
+	hdr->exp_statsn = cpu_to_be32(conn->exp_statsn);
+
+	hdr->offset = cpu_to_be32(ctask->total_length -
+				  transport_data_cnt -
+				  ctask->unsol_count);
+
+	if (ctask->unsol_count > conn->max_xmit_dlength) {
+		hton24(hdr->dlength, conn->max_xmit_dlength);
+		ctask->data_count = conn->max_xmit_dlength;
+		hdr->flags = 0;
+	} else {
+		hton24(hdr->dlength, ctask->unsol_count);
+		ctask->data_count = ctask->unsol_count;
+		hdr->flags = ISCSI_FLAG_CMD_FINAL;
+	}
+}
+EXPORT_SYMBOL_GPL(iscsi_prep_unsolicit_data_pdu);
+
+/**
+ * iscsi_prep_scsi_cmd_pdu - prep iscsi scsi cmd pdu
+ * @ctask: iscsi cmd task
+ *
+ * Prep basic iSCSI PDU fields for a scsi cmd pdu. The LLD should set
+ * fields like dlength or final based on how much data it sends
+ */
+static void iscsi_prep_scsi_cmd_pdu(struct iscsi_cmd_task *ctask)
+{
+	struct iscsi_conn *conn = ctask->conn;
+	struct iscsi_session *session = conn->session;
+	struct iscsi_cmd *hdr = ctask->hdr;
+	struct scsi_cmnd *sc = ctask->sc;
+
+        hdr->opcode = ISCSI_OP_SCSI_CMD;
+        hdr->flags = ISCSI_ATTR_SIMPLE;
+        int_to_scsilun(sc->device->lun, (struct scsi_lun *)hdr->lun);
+        hdr->itt = ctask->itt | (conn->id << ISCSI_CID_SHIFT) |
+                         (session->age << ISCSI_AGE_SHIFT);
+        hdr->data_length = cpu_to_be32(sc->request_bufflen);
+        hdr->cmdsn = cpu_to_be32(session->cmdsn);
+        session->cmdsn++;
+        hdr->exp_statsn = cpu_to_be32(conn->exp_statsn);
+        memcpy(hdr->cdb, sc->cmnd, sc->cmd_len);
+        memset(&hdr->cdb[sc->cmd_len], 0, MAX_COMMAND_SIZE - sc->cmd_len);
+
+	if (sc->sc_data_direction == DMA_TO_DEVICE) {
+		hdr->flags |= ISCSI_FLAG_CMD_WRITE;
+		/*
+		 * Write counters:
+		 *
+		 *	imm_count	bytes to be sent right after
+		 *			SCSI PDU Header
+		 *
+		 *	unsol_count	bytes(as Data-Out) to be sent
+		 *			without	R2T ack right after
+		 *			immediate data
+		 *
+		 *	r2t_data_count	bytes to be sent via R2T ack's
+		 *
+		 *      pad_count       bytes to be sent as zero-padding
+		 */
+		ctask->imm_count = 0;
+		ctask->unsol_count = 0;
+		ctask->unsol_datasn = 0;
+
+		if (session->imm_data_en) {
+			if (ctask->total_length >= session->first_burst)
+				ctask->imm_count = min(session->first_burst,
+							conn->max_xmit_dlength);
+			else
+				ctask->imm_count = min(ctask->total_length,
+							conn->max_xmit_dlength);
+			hton24(ctask->hdr->dlength, ctask->imm_count);
+		} else
+			zero_data(ctask->hdr->dlength);
+
+		if (!session->initial_r2t_en)
+			ctask->unsol_count = min(session->first_burst,
+				ctask->total_length) - ctask->imm_count;
+		if (!ctask->unsol_count)
+			/* No unsolicit Data-Out's */
+			ctask->hdr->flags |= ISCSI_FLAG_CMD_FINAL;
+	} else {
+		ctask->datasn = 0;
+		hdr->flags |= ISCSI_FLAG_CMD_FINAL;
+		zero_data(hdr->dlength);
+
+		if (sc->sc_data_direction == DMA_FROM_DEVICE)
+			hdr->flags |= ISCSI_FLAG_CMD_READ;
+	}
+
+	conn->scsicmd_pdus_cnt++;
+}
+EXPORT_SYMBOL_GPL(iscsi_prep_scsi_cmd_pdu);
+
+/**
+ * iscsi_complete_command - return command back to scsi-ml
+ * @session: iscsi session
+ * @ctask: iscsi cmd task
+ *
+ * Must be called with session lock.
+ * This function returns the scsi command to scsi-ml and returns
+ * the cmd task to the pool of available cmd tasks.
+ */
+static void iscsi_complete_command(struct iscsi_session *session,
+				   struct iscsi_cmd_task *ctask)
+{
+	struct scsi_cmnd *sc = ctask->sc;
+
+	ctask->sc = NULL;
+	list_del_init(&ctask->running);
+	__kfifo_put(session->cmdpool.queue, (void*)&ctask, sizeof(void*));
+	sc->scsi_done(sc);
+}
+
+/**
+ * iscsi_cmd_rsp - SCSI Command Response processing
+ * @conn: iscsi connection
+ * @hdr: iscsi header
+ * @ctask: scsi command task
+ * @data: cmd data buffer
+ * @datalen: len of buffer
+ *
+ * iscsi_cmd_rsp sets up the scsi_cmnd fields based on the PDU and
+ * then completes the command and task.
+ **/
+static int iscsi_scsi_cmd_rsp(struct iscsi_conn *conn, struct iscsi_hdr *hdr,
+			      struct iscsi_cmd_task *ctask, char *data,
+			      int datalen)
+{
+	int rc;
+	struct iscsi_cmd_rsp *rhdr = (struct iscsi_cmd_rsp *)hdr;
+	struct iscsi_session *session = conn->session;
+	struct scsi_cmnd *sc = ctask->sc;
+
+	rc = iscsi_check_assign_cmdsn(session, (struct iscsi_nopin*)rhdr);
+	if (rc) {
+		sc->result = DID_ERROR << 16;
+		goto out;
+	}
+
+	conn->exp_statsn = be32_to_cpu(rhdr->statsn) + 1;
+
+	sc->result = (DID_OK << 16) | rhdr->cmd_status;
+
+	if (rhdr->response != ISCSI_STATUS_CMD_COMPLETED) {
+		sc->result = DID_ERROR << 16;
+		goto out;
+	}
+
+	if (rhdr->cmd_status == SAM_STAT_CHECK_CONDITION) {
+		int senselen;
+
+		if (datalen < 2) {
+invalid_datalen:
+			printk(KERN_ERR "Got CHECK_CONDITION but invalid "
+			       "data buffer size of %d\n", datalen);
+			sc->result = DID_BAD_TARGET << 16;
+			goto out;
+		}
+
+		senselen = (data[0] << 8) | data[1];
+		if (datalen < senselen)
+			goto invalid_datalen;
+
+		memcpy(sc->sense_buffer, data + 2,
+		       min(senselen, SCSI_SENSE_BUFFERSIZE));
+		debug_scsi("copied %d bytes of sense\n",
+			   min(senselen, SCSI_SENSE_BUFFERSIZE));
+	}
+
+	if (sc->sc_data_direction == DMA_TO_DEVICE)
+		goto out;
+
+	if (rhdr->flags & ISCSI_FLAG_CMD_UNDERFLOW) {
+		int res_count = be32_to_cpu(rhdr->residual_count);
+
+		if (res_count > 0 && res_count <= sc->request_bufflen)
+			sc->resid = res_count;
+		else
+			sc->result = (DID_BAD_TARGET << 16) | rhdr->cmd_status;
+	} else if (rhdr->flags & ISCSI_FLAG_CMD_BIDI_UNDERFLOW)
+		sc->result = (DID_BAD_TARGET << 16) | rhdr->cmd_status;
+	else if (rhdr->flags & ISCSI_FLAG_CMD_OVERFLOW)
+		sc->resid = be32_to_cpu(rhdr->residual_count);
+
+out:
+	debug_scsi("done [sc %lx res %d itt 0x%x]\n",
+		   (long)sc, sc->result, ctask->itt);
+	conn->scsirsp_pdus_cnt++;
+
+	iscsi_complete_command(conn->session, ctask);
+	return rc;
+}
+
+/**
+ * __iscsi_complete_pdu - complete pdu
+ * @conn: iscsi conn
+ * @hdr: iscsi header
+ * @data: data buffer
+ * @datalen: len of data buffer
+ *
+ * Completes pdu processing by freeing any resources allocated at
+ * queuecommand or send generic. session lock must be held and verify
+ * itt must have been called.
+ */
+int __iscsi_complete_pdu(struct iscsi_conn *conn, struct iscsi_hdr *hdr,
+			 char *data, int datalen)
+{
+	struct iscsi_session *session = conn->session;
+	int opcode = hdr->opcode & ISCSI_OPCODE_MASK, rc = 0;
+	struct iscsi_cmd_task *ctask;
+	struct iscsi_mgmt_task *mtask;
+	uint32_t itt;
+
+	if (hdr->itt != cpu_to_be32(ISCSI_RESERVED_TAG))
+		itt = hdr->itt & ISCSI_ITT_MASK;
+	else
+		itt = hdr->itt;
+
+	if (itt < session->cmds_max) {
+		ctask = session->cmds[itt];
+
+		debug_scsi("cmdrsp [op 0x%x cid %d itt 0x%x len %d]\n",
+			   opcode, conn->id, ctask->itt, datalen);
+
+		switch(opcode) {
+		case ISCSI_OP_SCSI_CMD_RSP:
+			BUG_ON((void*)ctask != ctask->sc->SCp.ptr);
+			rc = iscsi_scsi_cmd_rsp(conn, hdr, ctask, data,
+						datalen);
+			break;
+		case ISCSI_OP_SCSI_DATA_IN:
+			BUG_ON((void*)ctask != ctask->sc->SCp.ptr);
+			if (hdr->flags & ISCSI_FLAG_DATA_STATUS) {
+				conn->scsirsp_pdus_cnt++;
+				iscsi_complete_command(session, ctask);
+			}
+			break;
+		case ISCSI_OP_R2T:
+			/* LLD handles this for now */
+			break;
+		default:
+			rc = ISCSI_ERR_BAD_OPCODE;
+			break;
+		}
+	} else if (itt >= ISCSI_MGMT_ITT_OFFSET &&
+		   itt < ISCSI_MGMT_ITT_OFFSET + session->mgmtpool_max) {
+		mtask = session->mgmt_cmds[itt - ISCSI_MGMT_ITT_OFFSET];
+
+		debug_scsi("immrsp [op 0x%x cid %d itt 0x%x len %d]\n",
+			   opcode, conn->id, mtask->itt, datalen);
+
+		switch(opcode) {
+		case ISCSI_OP_LOGIN_RSP:
+		case ISCSI_OP_TEXT_RSP:
+		case ISCSI_OP_LOGOUT_RSP:
+			rc = iscsi_check_assign_cmdsn(session,
+						 (struct iscsi_nopin*)hdr);
+			if (rc)
+				break;
+
+			rc = iscsi_recv_pdu(conn->cls_conn, hdr, data, datalen);
+			list_del(&mtask->running);
+			if (conn->login_mtask != mtask)
+				__kfifo_put(session->mgmtpool.queue,
+					    (void*)&mtask, sizeof(void*));
+			break;
+		case ISCSI_OP_SCSI_TMFUNC_RSP:
+			rc = iscsi_check_assign_cmdsn(session,
+						 (struct iscsi_nopin*)hdr);
+			if (rc)
+				break;
+
+			if (datalen) {
+				rc = ISCSI_ERR_PROTO;
+				break;
+			}
+			conn->tmfrsp_pdus_cnt++;
+			if (conn->tmabort_state == TMABORT_INITIAL) {
+				conn->tmabort_state =
+					((struct iscsi_tm_rsp *)hdr)->
+					response == ISCSI_TMF_RSP_COMPLETE ?
+						TMABORT_SUCCESS:TMABORT_FAILED;
+				/* unblock eh_abort() */
+				wake_up(&conn->ehwait);
+			}
+			break;
+		case ISCSI_OP_NOOP_IN:
+			if (hdr->ttt != ISCSI_RESERVED_TAG) {
+				rc = ISCSI_ERR_PROTO;
+				break;
+			}
+			rc = iscsi_check_assign_cmdsn(session,
+						(struct iscsi_nopin*)hdr);
+			if (rc)
+				break;
+			conn->exp_statsn = be32_to_cpu(hdr->statsn) + 1;
+
+			rc = iscsi_recv_pdu(conn->cls_conn, hdr, data, datalen);
+			list_del(&mtask->running);
+			if (conn->login_mtask != mtask)
+				__kfifo_put(session->mgmtpool.queue,
+					    (void*)&mtask, sizeof(void*));
+			break;
+		default:
+			rc = ISCSI_ERR_BAD_OPCODE;
+			break;
+		}
+	} else if (itt == ISCSI_RESERVED_TAG) {
+		switch(opcode) {
+		case ISCSI_OP_NOOP_IN:
+			if (!datalen) {
+				rc = iscsi_check_assign_cmdsn(session,
+						 (struct iscsi_nopin*)hdr);
+				if (!rc && hdr->ttt != ISCSI_RESERVED_TAG)
+					rc = iscsi_recv_pdu(conn->cls_conn,
+							    hdr, NULL, 0);
+			} else
+				rc = ISCSI_ERR_PROTO;
+			break;
+		case ISCSI_OP_REJECT:
+			/* we need sth like iscsi_reject_rsp()*/
+		case ISCSI_OP_ASYNC_EVENT:
+			/* we need sth like iscsi_async_event_rsp() */
+			rc = ISCSI_ERR_BAD_OPCODE;
+			break;
+		default:
+			rc = ISCSI_ERR_BAD_OPCODE;
+			break;
+		}
+	} else
+		rc = ISCSI_ERR_BAD_ITT;
+
+	return rc;
+}
+EXPORT_SYMBOL_GPL(__iscsi_complete_pdu);
+
+int iscsi_complete_pdu(struct iscsi_conn *conn, struct iscsi_hdr *hdr,
+		       char *data, int datalen)
+{
+	int rc;
+
+	spin_lock(&conn->session->lock);
+	rc = __iscsi_complete_pdu(conn, hdr, data, datalen);
+	spin_unlock(&conn->session->lock);
+	return rc;
+}
+EXPORT_SYMBOL_GPL(iscsi_complete_pdu);
+
+/* verify itt (itt encoding: age+cid+itt) */
+int iscsi_verify_itt(struct iscsi_conn *conn, struct iscsi_hdr *hdr,
+		     uint32_t *ret_itt)
+{
+	struct iscsi_session *session = conn->session;
+	struct iscsi_cmd_task *ctask;
+	uint32_t itt;
+
+	if (hdr->itt != cpu_to_be32(ISCSI_RESERVED_TAG)) {
+		if ((hdr->itt & ISCSI_AGE_MASK) !=
+		    (session->age << ISCSI_AGE_SHIFT)) {
+			printk(KERN_ERR "iscsi_tcp: received itt %x expected "
+				"session age (%x)\n", hdr->itt,
+				session->age & ISCSI_AGE_MASK);
+			return ISCSI_ERR_BAD_ITT;
+		}
+
+		if ((hdr->itt & ISCSI_CID_MASK) !=
+		    (conn->id << ISCSI_CID_SHIFT)) {
+			printk(KERN_ERR "iscsi_tcp: received itt %x, expected "
+				"CID (%x)\n", hdr->itt, conn->id);
+			return ISCSI_ERR_BAD_ITT;
+		}
+		itt = hdr->itt & ISCSI_ITT_MASK;
+	} else
+		itt = hdr->itt;
+
+	if (itt < session->cmds_max) {
+		ctask = session->cmds[itt];
+
+		if (!ctask->sc) {
+			printk(KERN_INFO "iscsi_tcp: dropping ctask with "
+			       "itt 0x%x\n", ctask->itt);
+			/* force drop */
+			return ISCSI_ERR_NO_SCSI_CMD;
+		}
+
+		if (ctask->sc->SCp.phase != session->age) {
+			printk(KERN_ERR "iscsi_tcp: ctask's session age %d, "
+				"expected %d\n", ctask->sc->SCp.phase,
+				session->age);
+			return ISCSI_ERR_SESSION_FAILED;
+		}
+	}
+
+	*ret_itt = itt;
+	return 0;
+}
+EXPORT_SYMBOL_GPL(iscsi_verify_itt);
+
+void iscsi_conn_failure(struct iscsi_conn *conn, enum iscsi_err err)
+{
+	struct iscsi_session *session = conn->session;
+	unsigned long flags;
+
+	spin_lock_irqsave(&session->lock, flags);
+	if (session->conn_cnt == 1 || session->leadconn == conn)
+		session->state = ISCSI_STATE_FAILED;
+	spin_unlock_irqrestore(&session->lock, flags);
+	set_bit(ISCSI_SUSPEND_BIT, &conn->suspend_tx);
+	set_bit(ISCSI_SUSPEND_BIT, &conn->suspend_rx);
+	iscsi_conn_error(conn->cls_conn, err);
+}
+EXPORT_SYMBOL_GPL(iscsi_conn_failure);
+
+/**
+ * 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_transport *tt;
+
+	if (unlikely(conn->suspend_tx)) {
+		debug_scsi("conn %d Tx suspended!\n", conn->id);
+		return 0;
+	}
+	tt = conn->session->tt;
+
+	/*
+	 * Transmit in the following order:
+	 *
+	 * 1) un-finished xmit (ctask or mtask)
+	 * 2) immediate control PDUs
+	 * 3) write data
+	 * 4) SCSI commands
+	 * 5) non-immediate control PDUs
+	 *
+	 * No need to lock around __kfifo_get as long as
+	 * there's one producer and one consumer.
+	 */
+
+	BUG_ON(conn->ctask && conn->mtask);
+
+	if (conn->ctask) {
+		if (tt->xmit_cmd_task(conn, conn->ctask))
+			goto again;
+		/* done with this in-progress ctask */
+		conn->ctask = NULL;
+	}
+	if (conn->mtask) {
+	        if (tt->xmit_mgmt_task(conn, conn->mtask))
+		        goto again;
+		/* done with this in-progress mtask */
+		conn->mtask = NULL;
+	}
+
+	/* process immediate first */
+        if (unlikely(__kfifo_len(conn->immqueue))) {
+	        while (__kfifo_get(conn->immqueue, (void*)&conn->mtask,
+			           sizeof(void*))) {
+			list_add_tail(&conn->mtask->running,
+				      &conn->mgmt_run_list);
+		        if (tt->xmit_mgmt_task(conn, conn->mtask))
+			        goto again;
+	        }
+		/* done with this mtask */
+		conn->mtask = NULL;
+	}
+
+	/* process command queue */
+	while (__kfifo_get(conn->xmitqueue, (void*)&conn->ctask,
+			   sizeof(void*))) {
+		/*
+		 * iscsi tcp may readd the task to the xmitqueue to send
+		 * write data
+		 */
+		if (list_empty(&conn->ctask->running))
+			list_add_tail(&conn->ctask->running, &conn->run_list);
+		if (tt->xmit_cmd_task(conn, conn->ctask))
+			goto again;
+	}
+	/* done with this ctask */
+	conn->ctask = NULL;
+
+	/* process the rest control plane PDUs, if any */
+        if (unlikely(__kfifo_len(conn->mgmtqueue))) {
+	        while (__kfifo_get(conn->mgmtqueue, (void*)&conn->mtask,
+			           sizeof(void*))) {
+			list_add_tail(&conn->mtask->running,
+				      &conn->mgmt_run_list);
+		        if (tt->xmit_mgmt_task(conn, conn->mtask))
+			        goto again;
+	        }
+		/* done with this mtask */
+		conn->mtask = NULL;
+	}
+
+	return 0;
+
+again:
+	if (unlikely(conn->suspend_tx))
+		return 0;
+
+	return -EAGAIN;
+}
+
+static void iscsi_xmitworker(void *data)
+{
+	struct iscsi_conn *conn = data;
+
+	/*
+	 * serialize Xmit worker on a per-connection basis.
+	 */
+	mutex_lock(&conn->xmitmutex);
+	if (iscsi_data_xmit(conn))
+		scsi_queue_work(conn->session->host, &conn->xmitwork);
+	mutex_unlock(&conn->xmitmutex);
+}
+
+enum {
+	FAILURE_BAD_HOST = 1,
+	FAILURE_SESSION_FAILED,
+	FAILURE_SESSION_FREED,
+	FAILURE_WINDOW_CLOSED,
+	FAILURE_SESSION_TERMINATE,
+	FAILURE_SESSION_RECOVERY_TIMEOUT,
+};
+
+int iscsi_queuecommand(struct scsi_cmnd *sc, void (*done)(struct scsi_cmnd *))
+{
+	struct Scsi_Host *host;
+	int reason = 0;
+	struct iscsi_session *session;
+	struct iscsi_conn *conn;
+	struct iscsi_cmd_task *ctask = NULL;
+
+	sc->scsi_done = done;
+	sc->result = 0;
+
+	host = sc->device->host;
+	session = iscsi_hostdata(host->hostdata);
+
+	spin_lock(&session->lock);
+
+	if (session->state != ISCSI_STATE_LOGGED_IN) {
+		if (session->recovery_failed) {
+			reason = FAILURE_SESSION_RECOVERY_TIMEOUT;
+			goto fault;
+		} else if (session->state == ISCSI_STATE_FAILED) {
+			reason = FAILURE_SESSION_FAILED;
+			goto reject;
+		} else if (session->state == ISCSI_STATE_TERMINATE) {
+			reason = FAILURE_SESSION_TERMINATE;
+			goto fault;
+		}
+		reason = FAILURE_SESSION_FREED;
+		goto fault;
+	}
+
+	/*
+	 * Check for iSCSI window and take care of CmdSN wrap-around
+	 */
+	if ((int)(session->max_cmdsn - session->cmdsn) < 0) {
+		reason = FAILURE_WINDOW_CLOSED;
+		goto reject;
+	}
+
+	conn = session->leadconn;
+
+	__kfifo_get(session->cmdpool.queue, (void*)&ctask, sizeof(void*));
+	sc->SCp.phase = session->age;
+	sc->SCp.ptr = (char *)ctask;
+
+	ctask->mtask = NULL;
+	ctask->conn = conn;
+	ctask->sc = sc;
+	INIT_LIST_HEAD(&ctask->running);
+	ctask->total_length = sc->request_bufflen;
+	iscsi_prep_scsi_cmd_pdu(ctask);
+
+	session->tt->init_cmd_task(ctask);
+
+	__kfifo_put(conn->xmitqueue, (void*)&ctask, sizeof(void*));
+	debug_scsi(
+	       "ctask enq [%s cid %d sc %lx itt 0x%x len %d cmdsn %d win %d]\n",
+		sc->sc_data_direction == DMA_TO_DEVICE ? "write" : "read",
+		conn->id, (long)sc, ctask->itt, sc->request_bufflen,
+		session->cmdsn, session->max_cmdsn - session->exp_cmdsn + 1);
+	spin_unlock(&session->lock);
+
+	scsi_queue_work(host, &conn->xmitwork);
+	return 0;
+
+reject:
+	spin_unlock(&session->lock);
+	debug_scsi("cmd 0x%x rejected (%d)\n", sc->cmnd[0], reason);
+	return SCSI_MLQUEUE_HOST_BUSY;
+
+fault:
+	spin_unlock(&session->lock);
+	printk(KERN_ERR "iscsi_tcp: cmd 0x%x is not queued (%d)\n",
+	       sc->cmnd[0], reason);
+	sc->result = (DID_NO_CONNECT << 16);
+	sc->resid = sc->request_bufflen;
+	sc->scsi_done(sc);
+	return 0;
+}
+EXPORT_SYMBOL_GPL(iscsi_queuecommand);
+
+int iscsi_change_queue_depth(struct scsi_device *sdev, int depth)
+{
+	if (depth > ISCSI_MAX_CMD_PER_LUN)
+		depth = ISCSI_MAX_CMD_PER_LUN;
+	scsi_adjust_queue_depth(sdev, scsi_get_tag_type(sdev), depth);
+	return sdev->queue_depth;
+}
+EXPORT_SYMBOL_GPL(iscsi_change_queue_depth);
+
+static int
+iscsi_conn_send_generic(struct iscsi_conn *conn, struct iscsi_hdr *hdr,
+			char *data, uint32_t data_size)
+{
+	struct iscsi_session *session = conn->session;
+	struct iscsi_nopout *nop = (struct iscsi_nopout *)hdr;
+	struct iscsi_mgmt_task *mtask;
+
+	spin_lock_bh(&session->lock);
+	if (session->state == ISCSI_STATE_TERMINATE) {
+		spin_unlock_bh(&session->lock);
+		return -EPERM;
+	}
+	if (hdr->opcode == (ISCSI_OP_LOGIN | ISCSI_OP_IMMEDIATE) ||
+	    hdr->opcode == (ISCSI_OP_TEXT | ISCSI_OP_IMMEDIATE))
+		/*
+		 * Login and Text are sent serially, in
+		 * request-followed-by-response sequence.
+		 * Same mtask can be used. Same ITT must be used.
+		 * Note that login_mtask is preallocated at conn_create().
+		 */
+		mtask = conn->login_mtask;
+	else {
+	        BUG_ON(conn->c_stage == ISCSI_CONN_INITIAL_STAGE);
+	        BUG_ON(conn->c_stage == ISCSI_CONN_STOPPED);
+
+		if (!__kfifo_get(session->mgmtpool.queue,
+				 (void*)&mtask, sizeof(void*))) {
+			spin_unlock_bh(&session->lock);
+			return -ENOSPC;
+		}
+	}
+
+	/*
+	 * pre-format CmdSN and ExpStatSN for outgoing PDU.
+	 */
+	if (hdr->itt != cpu_to_be32(ISCSI_RESERVED_TAG)) {
+		hdr->itt = mtask->itt | (conn->id << ISCSI_CID_SHIFT) |
+			   (session->age << ISCSI_AGE_SHIFT);
+		nop->cmdsn = cpu_to_be32(session->cmdsn);
+		if (conn->c_stage == ISCSI_CONN_STARTED &&
+		    !(hdr->opcode & ISCSI_OP_IMMEDIATE))
+			session->cmdsn++;
+	} else
+		/* do not advance CmdSN */
+		nop->cmdsn = cpu_to_be32(session->cmdsn);
+
+	nop->exp_statsn = cpu_to_be32(conn->exp_statsn);
+
+	if (data_size) {
+		memcpy(mtask->data, data, data_size);
+		mtask->data_count = data_size;
+	} else
+		mtask->data_count = 0;
+
+	INIT_LIST_HEAD(&mtask->running);
+	memcpy(mtask->hdr, hdr, sizeof(struct iscsi_hdr));
+	if (session->tt->init_mgmt_task)
+		session->tt->init_mgmt_task(conn, mtask, data, data_size);
+	spin_unlock_bh(&session->lock);
+
+	debug_scsi("mgmtpdu [op 0x%x hdr->itt 0x%x datalen %d]\n",
+		   hdr->opcode, hdr->itt, data_size);
+
+	/*
+	 * since send_pdu() could be called at least from two contexts,
+	 * we need to serialize __kfifo_put, so we don't have to take
+	 * additional lock on fast data-path
+	 */
+        if (hdr->opcode & ISCSI_OP_IMMEDIATE)
+	        __kfifo_put(conn->immqueue, (void*)&mtask, sizeof(void*));
+	else
+	        __kfifo_put(conn->mgmtqueue, (void*)&mtask, sizeof(void*));
+
+	scsi_queue_work(session->host, &conn->xmitwork);
+	return 0;
+}
+
+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;
+	int rc;
+
+	mutex_lock(&conn->xmitmutex);
+	rc = iscsi_conn_send_generic(conn, hdr, data, data_size);
+	mutex_unlock(&conn->xmitmutex);
+
+	return rc;
+}
+EXPORT_SYMBOL_GPL(iscsi_conn_send_pdu);
+
+void iscsi_session_recovery_timedout(struct iscsi_cls_session *cls_session)
+{
+	struct iscsi_session *session = class_to_transport_session(cls_session);
+	struct iscsi_conn *conn = session->leadconn;
+
+	spin_lock_bh(&session->lock);
+	if (session->state != ISCSI_STATE_LOGGED_IN) {
+		session->recovery_failed = 1;
+		if (conn)
+			wake_up(&conn->ehwait);
+	}
+	spin_unlock_bh(&session->lock);
+}
+EXPORT_SYMBOL_GPL(iscsi_session_recovery_timedout);
+
+int iscsi_eh_host_reset(struct scsi_cmnd *sc)
+{
+	struct Scsi_Host *host = sc->device->host;
+	struct iscsi_session *session = iscsi_hostdata(host->hostdata);
+	struct iscsi_conn *conn = session->leadconn;
+	int fail_session = 0;
+
+	spin_lock_bh(&session->lock);
+	if (session->state == ISCSI_STATE_TERMINATE) {
+failed:
+		debug_scsi("failing host reset: session terminated "
+			   "[CID %d age %d]", conn->id, session->age);
+		spin_unlock_bh(&session->lock);
+		return FAILED;
+	}
+
+	if (sc->SCp.phase == session->age) {
+		debug_scsi("failing connection CID %d due to SCSI host reset",
+			   conn->id);
+		fail_session = 1;
+	}
+	spin_unlock_bh(&session->lock);
+
+	/*
+	 * we drop the lock here but the leadconn cannot be destoyed while
+	 * we are in the scsi eh
+	 */
+	if (fail_session) {
+		iscsi_conn_failure(conn, ISCSI_ERR_CONN_FAILED);
+		/*
+		 * if userspace cannot respond then we must kick this off
+		 * here for it
+		 */
+		iscsi_start_session_recovery(session, conn, STOP_CONN_RECOVER);
+	}
+
+	debug_scsi("iscsi_eh_host_reset wait for relogin\n");
+	wait_event_interruptible(conn->ehwait,
+				 session->state == ISCSI_STATE_TERMINATE ||
+				 session->state == ISCSI_STATE_LOGGED_IN ||
+				 session->recovery_failed);
+	if (signal_pending(current))
+		flush_signals(current);
+
+	spin_lock_bh(&session->lock);
+	if (session->state == ISCSI_STATE_LOGGED_IN)
+		printk(KERN_INFO "host reset succeeded\n");
+	else
+		goto failed;
+	spin_unlock_bh(&session->lock);
+
+	return SUCCESS;
+}
+EXPORT_SYMBOL_GPL(iscsi_eh_host_reset);
+
+static void iscsi_tmabort_timedout(unsigned long data)
+{
+	struct iscsi_cmd_task *ctask = (struct iscsi_cmd_task *)data;
+	struct iscsi_conn *conn = ctask->conn;
+	struct iscsi_session *session = conn->session;
+
+	spin_lock(&session->lock);
+	if (conn->tmabort_state == TMABORT_INITIAL) {
+		conn->tmabort_state = TMABORT_TIMEDOUT;
+		debug_scsi("tmabort timedout [sc %p itt 0x%x]\n",
+			ctask->sc, ctask->itt);
+		/* unblock eh_abort() */
+		wake_up(&conn->ehwait);
+	}
+	spin_unlock(&session->lock);
+}
+
+/* must be called with the mutex lock */
+static int iscsi_exec_abort_task(struct scsi_cmnd *sc,
+				 struct iscsi_cmd_task *ctask)
+{
+	struct iscsi_conn *conn = ctask->conn;
+	struct iscsi_session *session = conn->session;
+	struct iscsi_tm *hdr = &conn->tmhdr;
+	int rc;
+
+	/*
+	 * ctask timed out but session is OK requests must be serialized.
+	 */
+	memset(hdr, 0, sizeof(struct iscsi_tm));
+	hdr->opcode = ISCSI_OP_SCSI_TMFUNC | ISCSI_OP_IMMEDIATE;
+	hdr->flags = ISCSI_TM_FUNC_ABORT_TASK;
+	hdr->flags |= ISCSI_FLAG_CMD_FINAL;
+	memcpy(hdr->lun, ctask->hdr->lun, sizeof(hdr->lun));
+	hdr->rtt = ctask->hdr->itt;
+	hdr->refcmdsn = ctask->hdr->cmdsn;
+
+	rc = iscsi_conn_send_generic(conn, (struct iscsi_hdr *)hdr,
+				     NULL, 0);
+	if (rc) {
+		iscsi_conn_failure(conn, ISCSI_ERR_CONN_FAILED);
+		debug_scsi("abort sent failure [itt 0x%x] %d", ctask->itt, rc);
+		return rc;
+	}
+
+	debug_scsi("abort sent [itt 0x%x]\n", ctask->itt);
+
+	spin_lock_bh(&session->lock);
+	ctask->mtask = (struct iscsi_mgmt_task *)
+			session->mgmt_cmds[(hdr->itt & ISCSI_ITT_MASK) -
+					ISCSI_MGMT_ITT_OFFSET];
+
+	if (conn->tmabort_state == TMABORT_INITIAL) {
+		conn->tmfcmd_pdus_cnt++;
+		conn->tmabort_timer.expires = 10*HZ + jiffies;
+		conn->tmabort_timer.function = iscsi_tmabort_timedout;
+		conn->tmabort_timer.data = (unsigned long)ctask;
+		add_timer(&conn->tmabort_timer);
+		debug_scsi("abort set timeout [itt 0x%x]", ctask->itt);
+	}
+	spin_unlock_bh(&session->lock);
+	mutex_unlock(&conn->xmitmutex);
+
+	/*
+	 * block eh thread until:
+	 *
+	 * 1) abort response
+	 * 2) abort timeout
+	 * 3) session is terminated or restarted or userspace has
+	 * given up on recovery
+	 */
+	wait_event_interruptible(conn->ehwait,
+				 sc->SCp.phase != session->age ||
+				 session->state != ISCSI_STATE_LOGGED_IN ||
+				 conn->tmabort_state != TMABORT_INITIAL ||
+				 session->recovery_failed);
+	if (signal_pending(current))
+		flush_signals(current);
+	del_timer_sync(&conn->tmabort_timer);
+
+	mutex_lock(&conn->xmitmutex);
+	return 0;
+}
+
+/*
+ * xmit mutex and session lock must be held
+ */
+#define iscsi_remove_task(tasktype)					\
+static struct iscsi_##tasktype *					\
+iscsi_remove_##tasktype(struct kfifo *fifo, uint32_t itt)		\
+{									\
+	int i, nr_tasks = __kfifo_len(fifo) / sizeof(void*);		\
+	struct iscsi_##tasktype *task;					\
+									\
+	debug_scsi("searching %d tasks\n", nr_tasks);			\
+									\
+	for (i = 0; i < nr_tasks; i++) {				\
+		__kfifo_get(fifo, (void*)&task, sizeof(void*));		\
+		debug_scsi("check task %u\n", task->itt);		\
+									\
+		if (task->itt == itt) {					\
+			debug_scsi("matched task\n");			\
+			break;						\
+		}							\
+									\
+		__kfifo_put(fifo, (void*)&task, sizeof(void*));		\
+	}								\
+	return NULL;							\
+}
+
+iscsi_remove_task(mgmt_task);
+iscsi_remove_task(cmd_task);
+
+static int iscsi_ctask_mtask_cleanup(struct iscsi_cmd_task *ctask)
+{
+	struct iscsi_conn *conn = ctask->conn;
+	struct iscsi_session *session = conn->session;
+
+	if (!ctask->mtask)
+		return -EINVAL;
+
+	if (!iscsi_remove_mgmt_task(conn->immqueue, ctask->mtask->itt))
+		list_del(&ctask->mtask->running);
+	__kfifo_put(session->mgmtpool.queue, (void*)&ctask->mtask,
+		    sizeof(void*));
+	ctask->mtask = NULL;
+	return 0;
+}
+
+/*
+ * session lock and xmitmutex must be held
+ */
+static void fail_command(struct iscsi_conn *conn, struct iscsi_cmd_task *ctask,
+			 int err)
+{
+	struct scsi_cmnd *sc;
+
+	conn->session->tt->cleanup_cmd_task(conn, ctask);
+	iscsi_ctask_mtask_cleanup(ctask);
+
+	sc = ctask->sc;
+	if (!sc)
+		return;
+	sc->result = err;
+	sc->resid = sc->request_bufflen;
+	iscsi_complete_command(conn->session, ctask);
+}
+
+int iscsi_eh_abort(struct scsi_cmnd *sc)
+{
+	struct iscsi_cmd_task *ctask = (struct iscsi_cmd_task *)sc->SCp.ptr;
+	struct iscsi_conn *conn = ctask->conn;
+	struct iscsi_session *session = conn->session;
+	struct iscsi_cmd_task *pending_ctask;
+	int rc;
+
+	conn->eh_abort_cnt++;
+	debug_scsi("aborting [sc %p itt 0x%x]\n", sc, ctask->itt);
+
+	mutex_lock(&conn->xmitmutex);
+	spin_lock_bh(&session->lock);
+
+	/*
+	 * If we are not logged in or we have started a new session
+	 * then let the host reset code handle this
+	 */
+	if (session->state != ISCSI_STATE_LOGGED_IN ||
+	    sc->SCp.phase != session->age)
+		goto failed;
+
+	/* ctask completed before time out */
+	if (!ctask->sc)
+		goto success;
+
+	/* what should we do here ? */
+	if (conn->ctask == ctask) {
+		printk(KERN_INFO "sc %p itt 0x%x partially sent. Failing "
+		       "abort\n", sc, ctask->itt);
+		goto failed;
+	}
+
+	/* check for the easy pending cmd abort */
+	pending_ctask = iscsi_remove_cmd_task(conn->xmitqueue, ctask->itt);
+	if (pending_ctask) {
+		/* iscsi_tcp queues write transfers on the xmitqueue */
+		if (list_empty(&pending_ctask->running)) {
+			debug_scsi("found pending task\n");
+			goto success;
+		} else
+			__kfifo_put(conn->xmitqueue, (void*)&pending_ctask,
+				    sizeof(void*));
+	}
+
+	conn->tmabort_state = TMABORT_INITIAL;
+
+	spin_unlock_bh(&session->lock);
+	rc = iscsi_exec_abort_task(sc, ctask);
+	spin_lock_bh(&session->lock);
+
+	iscsi_ctask_mtask_cleanup(ctask);
+	if (rc || sc->SCp.phase != session->age ||
+	    session->state != ISCSI_STATE_LOGGED_IN)
+		goto failed;
+
+	/* ctask completed before tmf abort response */
+	if (!ctask->sc) {
+		debug_scsi("sc completed while abort in progress\n");
+		goto success;
+	}
+
+	if (conn->tmabort_state != TMABORT_SUCCESS) {
+		spin_unlock_bh(&session->lock);
+		iscsi_conn_failure(conn, ISCSI_ERR_CONN_FAILED);
+		spin_lock_bh(&session->lock);
+		goto failed;
+	}
+
+success:
+	debug_scsi("abort success [sc %lx itt 0x%x]\n", (long)sc, ctask->itt);
+	spin_unlock_bh(&session->lock);
+
+	/*
+	 * clean up task if aborted. we have the xmitmutex so grab
+	 * the recv lock as a writer
+	 */
+	write_lock_bh(conn->recv_lock);
+	spin_lock(&session->lock);
+	fail_command(conn, ctask, DID_ABORT << 16);
+	spin_unlock(&session->lock);
+	write_unlock_bh(conn->recv_lock);
+
+	mutex_unlock(&conn->xmitmutex);
+	return SUCCESS;
+
+failed:
+	spin_unlock_bh(&session->lock);
+	mutex_unlock(&conn->xmitmutex);
+
+	debug_scsi("abort failed [sc %lx itt 0x%x]\n", (long)sc, ctask->itt);
+	return FAILED;
+}
+EXPORT_SYMBOL_GPL(iscsi_eh_abort);
+
+int
+iscsi_pool_init(struct iscsi_queue *q, int max, void ***items, int item_size)
+{
+	int i;
+
+	*items = kmalloc(max * sizeof(void*), GFP_KERNEL);
+	if (*items == NULL)
+		return -ENOMEM;
+
+	q->max = max;
+	q->pool = kmalloc(max * sizeof(void*), GFP_KERNEL);
+	if (q->pool == NULL) {
+		kfree(*items);
+		return -ENOMEM;
+	}
+
+	q->queue = kfifo_init((void*)q->pool, max * sizeof(void*),
+			      GFP_KERNEL, NULL);
+	if (q->queue == ERR_PTR(-ENOMEM)) {
+		kfree(q->pool);
+		kfree(*items);
+		return -ENOMEM;
+	}
+
+	for (i = 0; i < max; i++) {
+		q->pool[i] = kmalloc(item_size, GFP_KERNEL);
+		if (q->pool[i] == NULL) {
+			int j;
+
+			for (j = 0; j < i; j++)
+				kfree(q->pool[j]);
+
+			kfifo_free(q->queue);
+			kfree(q->pool);
+			kfree(*items);
+			return -ENOMEM;
+		}
+		memset(q->pool[i], 0, item_size);
+		(*items)[i] = q->pool[i];
+		__kfifo_put(q->queue, (void*)&q->pool[i], sizeof(void*));
+	}
+	return 0;
+}
+EXPORT_SYMBOL_GPL(iscsi_pool_init);
+
+void iscsi_pool_free(struct iscsi_queue *q, void **items)
+{
+	int i;
+
+	for (i = 0; i < q->max; i++)
+		kfree(items[i]);
+	kfree(q->pool);
+	kfree(items);
+}
+EXPORT_SYMBOL_GPL(iscsi_pool_free);
+
+/*
+ * iSCSI Session's hostdata organization:
+ *
+ *    *------------------* <== hostdata_session(host->hostdata)
+ *    | ptr to class sess|
+ *    |------------------| <== iscsi_hostdata(host->hostdata)
+ *    | iscsi_session    |
+ *    *------------------*
+ */
+
+#define hostdata_privsize(_sz)	(sizeof(unsigned long) + _sz + \
+				 _sz % sizeof(unsigned long))
+
+#define hostdata_session(_hostdata) (iscsi_ptr(*(unsigned long *)_hostdata))
+
+/**
+ * iscsi_session_setup - create iscsi cls session and host and session
+ * @scsit: scsi transport template
+ * @iscsit: iscsi transport template
+ * @initial_cmdsn: initial CmdSN
+ * @hostno: host no allocated
+ *
+ * This can be used by software iscsi_transports that allocate
+ * a session per scsi host.
+ **/
+struct iscsi_cls_session *
+iscsi_session_setup(struct iscsi_transport *iscsit,
+		    struct scsi_transport_template *scsit,
+		    int cmd_task_size, int mgmt_task_size,
+		    uint32_t initial_cmdsn, uint32_t *hostno)
+{
+	struct Scsi_Host *shost;
+	struct iscsi_session *session;
+	struct iscsi_cls_session *cls_session;
+	int cmd_i;
+
+	shost = scsi_host_alloc(iscsit->host_template,
+				hostdata_privsize(sizeof(*session)));
+	if (!shost)
+		return NULL;
+
+	shost->max_id = 1;
+	shost->max_channel = 0;
+	shost->max_lun = iscsit->max_lun;
+	shost->max_cmd_len = iscsit->max_cmd_len;
+	shost->transportt = scsit;
+	shost->transportt->create_work_queue = 1;
+	*hostno = shost->host_no;
+
+	session = iscsi_hostdata(shost->hostdata);
+	memset(session, 0, sizeof(struct iscsi_session));
+	session->host = shost;
+	session->state = ISCSI_STATE_FREE;
+	session->mgmtpool_max = ISCSI_MGMT_CMDS_MAX;
+	session->cmds_max = ISCSI_XMIT_CMDS_MAX;
+	session->cmdsn = initial_cmdsn;
+	session->exp_cmdsn = initial_cmdsn + 1;
+	session->max_cmdsn = initial_cmdsn + 1;
+	session->max_r2t = 1;
+	session->tt = iscsit;
+
+	/* initialize SCSI PDU commands pool */
+	if (iscsi_pool_init(&session->cmdpool, session->cmds_max,
+			    (void***)&session->cmds,
+			    cmd_task_size + sizeof(struct iscsi_cmd_task)))
+		goto cmdpool_alloc_fail;
+
+	/* pre-format cmds pool with ITT */
+	for (cmd_i = 0; cmd_i < session->cmds_max; cmd_i++) {
+		struct iscsi_cmd_task *ctask = session->cmds[cmd_i];
+
+		if (cmd_task_size)
+			ctask->dd_data = &ctask[1];
+		ctask->itt = cmd_i;
+	}
+
+	spin_lock_init(&session->lock);
+	INIT_LIST_HEAD(&session->connections);
+
+	/* initialize immediate command pool */
+	if (iscsi_pool_init(&session->mgmtpool, session->mgmtpool_max,
+			   (void***)&session->mgmt_cmds,
+			   mgmt_task_size + sizeof(struct iscsi_mgmt_task)))
+		goto mgmtpool_alloc_fail;
+
+
+	/* pre-format immediate cmds pool with ITT */
+	for (cmd_i = 0; cmd_i < session->mgmtpool_max; cmd_i++) {
+		struct iscsi_mgmt_task *mtask = session->mgmt_cmds[cmd_i];
+
+		if (mgmt_task_size)
+			mtask->dd_data = &mtask[1];
+		mtask->itt = ISCSI_MGMT_ITT_OFFSET + cmd_i;
+		mtask->data = kmalloc(DEFAULT_MAX_RECV_DATA_SEGMENT_LENGTH,
+				     GFP_KERNEL);
+		if (!mtask->data) {
+			int j;
+
+			for (j = 0; j < cmd_i; j++)
+				kfree(session->mgmt_cmds[j]->data);
+			goto immdata_alloc_fail;
+		}
+	}
+
+	if (scsi_add_host(shost, NULL))
+		goto add_host_fail;
+
+	cls_session = iscsi_create_session(shost, iscsit, 0);
+	if (!cls_session)
+		goto cls_session_fail;
+	*(unsigned long*)shost->hostdata = (unsigned long)cls_session;
+
+	return cls_session;
+
+cls_session_fail:
+	scsi_remove_host(shost);
+add_host_fail:
+	for (cmd_i = 0; cmd_i < session->mgmtpool_max; cmd_i++)
+		kfree(session->mgmt_cmds[cmd_i]->data);
+immdata_alloc_fail:
+	iscsi_pool_free(&session->mgmtpool, (void**)session->mgmt_cmds);
+mgmtpool_alloc_fail:
+	iscsi_pool_free(&session->cmdpool, (void**)session->cmds);
+cmdpool_alloc_fail:
+	scsi_host_put(shost);
+	return NULL;
+}
+EXPORT_SYMBOL_GPL(iscsi_session_setup);
+
+/**
+ * iscsi_session_teardown - destroy session, host, and cls_session
+ * shost: scsi host
+ *
+ * This can be used by software iscsi_transports that allocate
+ * a session per scsi host.
+ **/
+void iscsi_session_teardown(struct iscsi_cls_session *cls_session)
+{
+	struct Scsi_Host *shost = iscsi_session_to_shost(cls_session);
+	struct iscsi_session *session = iscsi_hostdata(shost->hostdata);
+	int cmd_i;
+
+	scsi_remove_host(shost);
+
+	for (cmd_i = 0; cmd_i < session->mgmtpool_max; cmd_i++)
+		kfree(session->mgmt_cmds[cmd_i]->data);
+
+	iscsi_pool_free(&session->mgmtpool, (void**)session->mgmt_cmds);
+	iscsi_pool_free(&session->cmdpool, (void**)session->cmds);
+
+	iscsi_destroy_session(cls_session);
+	scsi_host_put(shost);
+}
+EXPORT_SYMBOL_GPL(iscsi_session_teardown);
+
+/**
+ * iscsi_conn_setup - create iscsi_cls_conn and iscsi_conn
+ * @cls_session: iscsi_cls_session
+ * @conn_idx: cid
+ **/
+struct iscsi_cls_conn *
+iscsi_conn_setup(struct iscsi_cls_session *cls_session, uint32_t conn_idx)
+{
+	struct iscsi_session *session = class_to_transport_session(cls_session);
+	struct iscsi_conn *conn;
+	struct iscsi_cls_conn *cls_conn;
+
+	cls_conn = iscsi_create_conn(cls_session, conn_idx);
+	if (!cls_conn)
+		return NULL;
+	conn = cls_conn->dd_data;
+	memset(conn, 0, sizeof(*conn));
+
+	conn->session = session;
+	conn->cls_conn = cls_conn;
+	conn->c_stage = ISCSI_CONN_INITIAL_STAGE;
+	conn->id = conn_idx;
+	conn->exp_statsn = 0;
+	conn->tmabort_state = TMABORT_INITIAL;
+	INIT_LIST_HEAD(&conn->run_list);
+	INIT_LIST_HEAD(&conn->mgmt_run_list);
+
+	/* initialize general xmit PDU commands queue */
+	conn->xmitqueue = kfifo_alloc(session->cmds_max * sizeof(void*),
+					GFP_KERNEL, NULL);
+	if (conn->xmitqueue == ERR_PTR(-ENOMEM))
+		goto xmitqueue_alloc_fail;
+
+	/* initialize general immediate & non-immediate PDU commands queue */
+	conn->immqueue = kfifo_alloc(session->mgmtpool_max * sizeof(void*),
+			                GFP_KERNEL, NULL);
+	if (conn->immqueue == ERR_PTR(-ENOMEM))
+		goto immqueue_alloc_fail;
+
+	conn->mgmtqueue = kfifo_alloc(session->mgmtpool_max * sizeof(void*),
+			                GFP_KERNEL, NULL);
+	if (conn->mgmtqueue == ERR_PTR(-ENOMEM))
+		goto mgmtqueue_alloc_fail;
+
+	INIT_WORK(&conn->xmitwork, iscsi_xmitworker, conn);
+
+	/* allocate login_mtask used for the login/text sequences */
+	spin_lock_bh(&session->lock);
+	if (!__kfifo_get(session->mgmtpool.queue,
+                         (void*)&conn->login_mtask,
+			 sizeof(void*))) {
+		spin_unlock_bh(&session->lock);
+		goto login_mtask_alloc_fail;
+	}
+	spin_unlock_bh(&session->lock);
+
+	init_timer(&conn->tmabort_timer);
+	mutex_init(&conn->xmitmutex);
+	init_waitqueue_head(&conn->ehwait);
+
+	return cls_conn;
+
+login_mtask_alloc_fail:
+	kfifo_free(conn->mgmtqueue);
+mgmtqueue_alloc_fail:
+	kfifo_free(conn->immqueue);
+immqueue_alloc_fail:
+	kfifo_free(conn->xmitqueue);
+xmitqueue_alloc_fail:
+	iscsi_destroy_conn(cls_conn);
+	return NULL;
+}
+EXPORT_SYMBOL_GPL(iscsi_conn_setup);
+
+/**
+ * iscsi_conn_teardown - teardown iscsi connection
+ * cls_conn: iscsi class connection
+ *
+ * TODO: we may need to make this into a two step process
+ * like scsi-mls remove + put host
+ */
+void iscsi_conn_teardown(struct iscsi_cls_conn *cls_conn)
+{
+	struct iscsi_conn *conn = cls_conn->dd_data;
+	struct iscsi_session *session = conn->session;
+	unsigned long flags;
+
+	mutex_lock(&conn->xmitmutex);
+	set_bit(ISCSI_SUSPEND_BIT, &conn->suspend_tx);
+	if (conn->c_stage == ISCSI_CONN_INITIAL_STAGE) {
+		if (session->tt->suspend_conn_recv)
+			session->tt->suspend_conn_recv(conn);
+
+		session->tt->terminate_conn(conn);
+	}
+
+	spin_lock_bh(&session->lock);
+	conn->c_stage = ISCSI_CONN_CLEANUP_WAIT;
+	if (session->leadconn == conn) {
+		/*
+		 * leading connection? then give up on recovery.
+		 */
+		session->state = ISCSI_STATE_TERMINATE;
+		wake_up(&conn->ehwait);
+	}
+	spin_unlock_bh(&session->lock);
+
+	mutex_unlock(&conn->xmitmutex);
+
+	/*
+	 * Block until all in-progress commands for this connection
+	 * time out or fail.
+	 */
+	for (;;) {
+		spin_lock_irqsave(session->host->host_lock, flags);
+		if (!session->host->host_busy) { /* OK for ERL == 0 */
+			spin_unlock_irqrestore(session->host->host_lock, flags);
+			break;
+		}
+		spin_unlock_irqrestore(session->host->host_lock, flags);
+		msleep_interruptible(500);
+		printk("conn_destroy(): host_busy %d host_failed %d\n",
+			session->host->host_busy, session->host->host_failed);
+		/*
+		 * force eh_abort() to unblock
+		 */
+		wake_up(&conn->ehwait);
+	}
+
+	spin_lock_bh(&session->lock);
+	__kfifo_put(session->mgmtpool.queue, (void*)&conn->login_mtask,
+		    sizeof(void*));
+	list_del(&conn->item);
+	if (list_empty(&session->connections))
+		session->leadconn = NULL;
+	if (session->leadconn && session->leadconn == conn)
+		session->leadconn = container_of(session->connections.next,
+			struct iscsi_conn, item);
+
+	if (session->leadconn == NULL)
+		/* no connections exits.. reset sequencing */
+		session->cmdsn = session->max_cmdsn = session->exp_cmdsn = 1;
+	spin_unlock_bh(&session->lock);
+
+	kfifo_free(conn->xmitqueue);
+	kfifo_free(conn->immqueue);
+	kfifo_free(conn->mgmtqueue);
+
+	iscsi_destroy_conn(cls_conn);
+}
+EXPORT_SYMBOL_GPL(iscsi_conn_teardown);
+
+int iscsi_conn_start(struct iscsi_cls_conn *cls_conn)
+{
+	struct iscsi_conn *conn = cls_conn->dd_data;
+	struct iscsi_session *session = conn->session;
+
+	if (session == NULL) {
+		printk(KERN_ERR "iscsi: can't start unbound connection\n");
+		return -EPERM;
+	}
+
+	spin_lock_bh(&session->lock);
+	conn->c_stage = ISCSI_CONN_STARTED;
+	session->state = ISCSI_STATE_LOGGED_IN;
+
+	switch(conn->stop_stage) {
+	case STOP_CONN_RECOVER:
+		/*
+		 * unblock eh_abort() if it is blocked. re-try all
+		 * commands after successful recovery
+		 */
+		session->conn_cnt++;
+		conn->stop_stage = 0;
+		conn->tmabort_state = TMABORT_INITIAL;
+		session->age++;
+		session->recovery_failed = 0;
+		spin_unlock_bh(&session->lock);
+
+		iscsi_unblock_session(session_to_cls(session));
+		wake_up(&conn->ehwait);
+		return 0;
+	case STOP_CONN_TERM:
+		session->conn_cnt++;
+		conn->stop_stage = 0;
+		break;
+	case STOP_CONN_SUSPEND:
+		conn->stop_stage = 0;
+		clear_bit(ISCSI_SUSPEND_BIT, &conn->suspend_rx);
+		clear_bit(ISCSI_SUSPEND_BIT, &conn->suspend_tx);
+		break;
+	default:
+		break;
+	}
+	spin_unlock_bh(&session->lock);
+
+	return 0;
+}
+EXPORT_SYMBOL_GPL(iscsi_conn_start);
+
+static void
+flush_control_queues(struct iscsi_session *session, struct iscsi_conn *conn)
+{
+	struct iscsi_mgmt_task *mtask, *tmp;
+
+	/* handle pending */
+	while (__kfifo_get(conn->immqueue, (void*)&mtask, sizeof(void*)) ||
+	       __kfifo_get(conn->mgmtqueue, (void*)&mtask, sizeof(void*))) {
+		if (mtask == conn->login_mtask)
+			continue;
+		debug_scsi("flushing pending mgmt task itt 0x%x\n", mtask->itt);
+		__kfifo_put(session->mgmtpool.queue, (void*)&mtask,
+			    sizeof(void*));
+	}
+
+	/* handle running */
+	list_for_each_entry_safe(mtask, tmp, &conn->mgmt_run_list, running) {
+		debug_scsi("flushing running mgmt task itt 0x%x\n", mtask->itt);
+		if (mtask == conn->login_mtask)
+			continue;
+		list_del(&mtask->running);
+		__kfifo_put(session->mgmtpool.queue, (void*)&conn->mtask,
+			   sizeof(void*));
+	}
+
+	conn->mtask = NULL;
+}
+
+/* Fail commands. Mutex and session lock held and recv side suspended */
+static void fail_all_commands(struct iscsi_conn *conn)
+{
+	struct iscsi_cmd_task *ctask, *tmp;
+
+	/* flush pending */
+	while (__kfifo_get(conn->xmitqueue, (void*)&ctask, sizeof(void*))) {
+		debug_scsi("failing pending sc %p itt 0x%x\n", ctask->sc,
+			   ctask->itt);
+		fail_command(conn, ctask, DID_BUS_BUSY << 16);
+	}
+
+	/* fail all other running */
+	list_for_each_entry_safe(ctask, tmp, &conn->run_list, running) {
+		debug_scsi("failing in progress sc %p itt 0x%x\n",
+			   ctask->sc, ctask->itt);
+		fail_command(conn, ctask, DID_BUS_BUSY << 16);
+	}
+
+	conn->ctask = NULL;
+}
+
+void iscsi_start_session_recovery(struct iscsi_session *session,
+				  struct iscsi_conn *conn, int flag)
+{
+	spin_lock_bh(&session->lock);
+	if (conn->stop_stage == STOP_CONN_RECOVER ||
+	    conn->stop_stage == STOP_CONN_TERM) {
+		spin_unlock_bh(&session->lock);
+		return;
+	}
+	conn->stop_stage = flag;
+	spin_unlock_bh(&session->lock);
+
+	if (session->tt->suspend_conn_recv)
+		session->tt->suspend_conn_recv(conn);
+
+	mutex_lock(&conn->xmitmutex);
+	spin_lock_bh(&session->lock);
+	conn->c_stage = ISCSI_CONN_STOPPED;
+	set_bit(ISCSI_SUSPEND_BIT, &conn->suspend_tx);
+
+	session->conn_cnt--;
+	if (session->conn_cnt == 0 || session->leadconn == conn)
+		session->state = ISCSI_STATE_FAILED;
+
+	spin_unlock_bh(&session->lock);
+
+	session->tt->terminate_conn(conn);
+	/*
+	 * flush queues.
+	 */
+	spin_lock_bh(&session->lock);
+	fail_all_commands(conn);
+	flush_control_queues(session, conn);
+	spin_unlock_bh(&session->lock);
+
+	/*
+	 * for connection level recovery we should not calculate
+	 * header digest. conn->hdr_size used for optimization
+	 * in hdr_extract() and will be re-negotiated at
+	 * set_param() time.
+	 */
+	if (flag == STOP_CONN_RECOVER) {
+		conn->hdrdgst_en = 0;
+		conn->datadgst_en = 0;
+
+		if (session->state == ISCSI_STATE_FAILED)
+			iscsi_block_session(session_to_cls(session));
+	}
+	mutex_unlock(&conn->xmitmutex);
+}
+EXPORT_SYMBOL_GPL(iscsi_start_session_recovery);
+
+void iscsi_conn_stop(struct iscsi_cls_conn *cls_conn, int flag)
+{
+	struct iscsi_conn *conn = cls_conn->dd_data;
+	struct iscsi_session *session = conn->session;
+
+	switch (flag) {
+	case STOP_CONN_RECOVER:
+	case STOP_CONN_TERM:
+		iscsi_start_session_recovery(session, conn, flag);
+		return;
+	case STOP_CONN_SUSPEND:
+		if (session->tt->suspend_conn_recv)
+			session->tt->suspend_conn_recv(conn);
+
+		mutex_lock(&conn->xmitmutex);
+		spin_lock_bh(&session->lock);
+
+		conn->stop_stage = flag;
+		conn->c_stage = ISCSI_CONN_STOPPED;
+		set_bit(ISCSI_SUSPEND_BIT, &conn->suspend_tx);
+
+		spin_unlock_bh(&session->lock);
+		mutex_unlock(&conn->xmitmutex);
+		break;
+	default:
+		printk(KERN_ERR "invalid stop flag %d\n", flag);
+	}
+}
+EXPORT_SYMBOL_GPL(iscsi_conn_stop);
+
+int iscsi_conn_bind(struct iscsi_cls_session *cls_session,
+		    struct iscsi_cls_conn *cls_conn, int is_leading)
+{
+	struct iscsi_session *session = class_to_transport_session(cls_session);
+	struct iscsi_conn *tmp = ERR_PTR(-EEXIST), *conn = cls_conn->dd_data;
+
+	/* lookup for existing connection */
+	spin_lock_bh(&session->lock);
+	list_for_each_entry(tmp, &session->connections, item) {
+		if (tmp == conn) {
+			if (conn->c_stage != ISCSI_CONN_STOPPED ||
+			    conn->stop_stage == STOP_CONN_TERM) {
+				printk(KERN_ERR "iscsi_tcp: can't bind "
+				       "non-stopped connection (%d:%d)\n",
+				       conn->c_stage, conn->stop_stage);
+				spin_unlock_bh(&session->lock);
+				return -EIO;
+			}
+			break;
+		}
+	}
+	if (tmp != conn) {
+		/* bind new iSCSI connection to session */
+		conn->session = session;
+		list_add(&conn->item, &session->connections);
+	}
+	spin_unlock_bh(&session->lock);
+
+	if (is_leading)
+		session->leadconn = conn;
+
+	/*
+	 * 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);
+
+MODULE_AUTHOR("Mike Christie");
+MODULE_DESCRIPTION("iSCSI library functions");
+MODULE_LICENSE("GPL");