[SCSI] open-iscsi/linux-iscsi-5 Initiator: Initiator code
authorAlex Aizman <itn780@yahoo.com>
Fri, 5 Aug 2005 02:30:08 +0000 (19:30 -0700)
committerJames Bottomley <jejb@mulgrave.(none)>
Sat, 6 Aug 2005 14:35:35 +0000 (09:35 -0500)
drivers/scsi/iscsi_tcp.c, iscsi data path.

Signed-off-by: Alex Aizman <itn780@yahoo.com>
Signed-off-by: Dmitry Yusupov <dmitry_yus@yahoo.com>
Signed-off-by: Mike Christie <michaelc@cs.wisc.edu>
Signed-off-by: James Bottomley <James.Bottomley@SteelEye.com>
drivers/scsi/iscsi_tcp.c [new file with mode: 0644]

diff --git a/drivers/scsi/iscsi_tcp.c b/drivers/scsi/iscsi_tcp.c
new file mode 100644 (file)
index 0000000..810e5e5
--- /dev/null
@@ -0,0 +1,3627 @@
+/*
+ * iSCSI Initiator over TCP/IP Data-Path
+ *
+ * Copyright (C) 2004 Dmitry Yusupov
+ * Copyright (C) 2004 Alex Aizman
+ * Copyright (C) 2005 Mike Christie
+ * 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.
+ *
+ * See the file COPYING included with this distribution for more details.
+ *
+ * Credits:
+ *     Christoph Hellwig
+ *     FUJITA Tomonori
+ *     Arne Redlich
+ *     Zhenyu Wang
+ */
+
+#include <linux/types.h>
+#include <linux/list.h>
+#include <linux/inet.h>
+#include <linux/blkdev.h>
+#include <linux/crypto.h>
+#include <linux/delay.h>
+#include <linux/kfifo.h>
+#include <linux/scatterlist.h>
+#include <net/tcp.h>
+#include <scsi/scsi_cmnd.h>
+#include <scsi/scsi_device.h>
+#include <scsi/scsi_eh.h>
+#include <scsi/scsi_request.h>
+#include <scsi/scsi_tcq.h>
+#include <scsi/scsi_host.h>
+#include <scsi/scsi.h>
+#include <scsi/scsi_transport_iscsi.h>
+
+#include "iscsi_tcp.h"
+
+MODULE_AUTHOR("Dmitry Yusupov <dmitry_yus@yahoo.com>, "
+             "Alex Aizman <itn780@yahoo.com>");
+MODULE_DESCRIPTION("iSCSI/TCP data-path");
+MODULE_LICENSE("GPL");
+
+/* #define DEBUG_TCP */
+/* #define DEBUG_SCSI */
+#define DEBUG_ASSERT
+
+#ifdef DEBUG_TCP
+#define debug_tcp(fmt...) printk(KERN_DEBUG "tcp: " fmt)
+#else
+#define debug_tcp(fmt...)
+#endif
+
+#ifdef DEBUG_SCSI
+#define debug_scsi(fmt...) printk(KERN_DEBUG "scsi: " fmt)
+#else
+#define debug_scsi(fmt...)
+#endif
+
+#ifndef DEBUG_ASSERT
+#ifdef BUG_ON
+#undef BUG_ON
+#endif
+#define BUG_ON(expr)
+#endif
+
+#define INVALID_SN_DELTA       0xffff
+
+static unsigned int iscsi_max_lun = 512;
+module_param_named(max_lun, iscsi_max_lun, uint, S_IRUGO);
+
+/* global data */
+static kmem_cache_t *taskcache;
+
+static inline void
+iscsi_buf_init_virt(struct iscsi_buf *ibuf, char *vbuf, int size)
+{
+       sg_init_one(&ibuf->sg, (u8 *)vbuf, size);
+       ibuf->sent = 0;
+}
+
+static inline void
+iscsi_buf_init_iov(struct iscsi_buf *ibuf, char *vbuf, int size)
+{
+       ibuf->sg.page = (void*)vbuf;
+       ibuf->sg.offset = (unsigned int)-1;
+       ibuf->sg.length = size;
+       ibuf->sent = 0;
+}
+
+static inline void*
+iscsi_buf_iov_base(struct iscsi_buf *ibuf)
+{
+       return (char*)ibuf->sg.page + ibuf->sent;
+}
+
+static inline void
+iscsi_buf_init_sg(struct iscsi_buf *ibuf, struct scatterlist *sg)
+{
+       /*
+        * Fastpath: sg element fits into single page
+        */
+       if (sg->length + sg->offset <= PAGE_SIZE && page_count(sg->page) >= 2) {
+               ibuf->sg.page = sg->page;
+               ibuf->sg.offset = sg->offset;
+               ibuf->sg.length = sg->length;
+       } else
+               iscsi_buf_init_iov(ibuf, page_address(sg->page), sg->length);
+       ibuf->sent = 0;
+}
+
+static inline int
+iscsi_buf_left(struct iscsi_buf *ibuf)
+{
+       int rc;
+
+       rc = ibuf->sg.length - ibuf->sent;
+       BUG_ON(rc < 0);
+       return rc;
+}
+
+static inline void
+iscsi_buf_init_hdr(struct iscsi_conn *conn, struct iscsi_buf *ibuf,
+                  char *vbuf, u8 *crc)
+{
+       iscsi_buf_init_virt(ibuf, vbuf, sizeof(struct iscsi_hdr));
+       if (conn->hdrdgst_en) {
+               crypto_digest_digest(conn->tx_tfm, &ibuf->sg, 1, crc);
+               ibuf->sg.length += sizeof(uint32_t);
+       }
+}
+
+static 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(SUSPEND_BIT, &conn->suspend_tx);
+       set_bit(SUSPEND_BIT, &conn->suspend_rx);
+       iscsi_conn_error(iscsi_handle(conn), err);
+}
+
+static inline 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;
+}
+
+static inline int
+iscsi_hdr_extract(struct iscsi_conn *conn)
+{
+       struct sk_buff *skb = conn->in.skb;
+
+       if (conn->in.copy >= conn->hdr_size &&
+           conn->in_progress == IN_PROGRESS_WAIT_HEADER) {
+               /*
+                * Zero-copy PDU Header: using connection context
+                * to store header pointer.
+                */
+               if (skb_shinfo(skb)->frag_list == NULL &&
+                   !skb_shinfo(skb)->nr_frags)
+                       conn->in.hdr = (struct iscsi_hdr *)
+                               ((char*)skb->data + conn->in.offset);
+               else {
+                       /* ignoring return code since we checked
+                        * in.copy before */
+                       skb_copy_bits(skb, conn->in.offset,
+                               &conn->hdr, conn->hdr_size);
+                       conn->in.hdr = &conn->hdr;
+               }
+               conn->in.offset += conn->hdr_size;
+               conn->in.copy -= conn->hdr_size;
+       } else {
+               int hdr_remains;
+               int copylen;
+
+               /*
+                * PDU header scattered across SKB's,
+                * copying it... This'll happen quite rarely.
+                */
+
+               if (conn->in_progress == IN_PROGRESS_WAIT_HEADER)
+                       conn->in.hdr_offset = 0;
+
+               hdr_remains = conn->hdr_size - conn->in.hdr_offset;
+               BUG_ON(hdr_remains <= 0);
+
+               copylen = min(conn->in.copy, hdr_remains);
+               skb_copy_bits(skb, conn->in.offset,
+                       (char*)&conn->hdr + conn->in.hdr_offset, copylen);
+
+               debug_tcp("PDU gather offset %d bytes %d in.offset %d "
+                      "in.copy %d\n", conn->in.hdr_offset, copylen,
+                      conn->in.offset, conn->in.copy);
+
+               conn->in.offset += copylen;
+               conn->in.copy -= copylen;
+               if (copylen < hdr_remains)  {
+                       conn->in_progress = IN_PROGRESS_HEADER_GATHER;
+                       conn->in.hdr_offset += copylen;
+                       return -EAGAIN;
+               }
+               conn->in.hdr = &conn->hdr;
+               conn->discontiguous_hdr_cnt++;
+               conn->in_progress = IN_PROGRESS_WAIT_HEADER;
+       }
+
+       return 0;
+}
+
+static inline void
+iscsi_ctask_cleanup(struct iscsi_conn *conn, struct iscsi_cmd_task *ctask)
+{
+       struct scsi_cmnd *sc = ctask->sc;
+       struct iscsi_session *session = conn->session;
+
+       spin_lock(&session->lock);
+       if (unlikely(!sc)) {
+               spin_unlock(&session->lock);
+               return;
+       }
+       if (sc->sc_data_direction == DMA_TO_DEVICE) {
+               struct iscsi_data_task *dtask, *n;
+               /* WRITE: cleanup Data-Out's if any */
+               spin_lock(&conn->lock);
+               list_for_each_entry_safe(dtask, n, &ctask->dataqueue, item) {
+                       list_del(&dtask->item);
+                       mempool_free(dtask, ctask->datapool);
+               }
+               spin_unlock(&conn->lock);
+       }
+       ctask->xmstate = XMSTATE_IDLE;
+       ctask->r2t = NULL;
+       ctask->sc = NULL;
+       __kfifo_put(session->cmdpool.queue, (void*)&ctask, sizeof(void*));
+       spin_unlock(&session->lock);
+}
+
+/**
+ * iscsi_cmd_rsp - SCSI Command Response processing
+ * @conn: iscsi connection
+ * @ctask: scsi command task
+ **/
+static int
+iscsi_cmd_rsp(struct iscsi_conn *conn, struct iscsi_cmd_task *ctask)
+{
+       int rc;
+       struct iscsi_cmd_rsp *rhdr = (struct iscsi_cmd_rsp *)conn->in.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 && conn->senselen) {
+               int sensecopy = min(conn->senselen, SCSI_SENSE_BUFFERSIZE);
+
+               memcpy(sc->sense_buffer, conn->data + 2, sensecopy);
+               debug_scsi("copied %d bytes of sense\n", sensecopy);
+       }
+
+       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_ctask_cleanup(conn, ctask);
+       sc->scsi_done(sc);
+       return rc;
+}
+
+/**
+ * iscsi_data_rsp - SCSI Data-In Response processing
+ * @conn: iscsi connection
+ * @ctask: scsi command task
+ **/
+static int
+iscsi_data_rsp(struct iscsi_conn *conn, struct iscsi_cmd_task *ctask)
+{
+       int rc;
+       struct iscsi_data_rsp *rhdr = (struct iscsi_data_rsp *)conn->in.hdr;
+       struct iscsi_session *session = conn->session;
+       int datasn = be32_to_cpu(rhdr->datasn);
+
+       rc = iscsi_check_assign_cmdsn(session, (struct iscsi_nopin*)rhdr);
+       if (rc)
+               return rc;
+       /*
+        * setup Data-In byte counter (gets decremented..)
+        */
+       ctask->data_count = conn->in.datalen;
+
+       if (conn->in.datalen == 0)
+               return 0;
+
+       if (ctask->datasn != datasn)
+               return ISCSI_ERR_DATASN;
+
+       ctask->datasn++;
+
+       ctask->data_offset = be32_to_cpu(rhdr->offset);
+       if (ctask->data_offset + conn->in.datalen > ctask->total_length)
+               return ISCSI_ERR_DATA_OFFSET;
+
+       if (rhdr->flags & ISCSI_FLAG_DATA_STATUS) {
+               struct scsi_cmnd *sc = ctask->sc;
+
+               conn->exp_statsn = be32_to_cpu(rhdr->statsn) + 1;
+               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;
+                               sc->result = (DID_OK << 16) | rhdr->cmd_status;
+                       } 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);
+                       sc->result = (DID_OK << 16) | rhdr->cmd_status;
+               } else
+                       sc->result = (DID_OK << 16) | rhdr->cmd_status;
+       }
+
+       conn->datain_pdus_cnt++;
+       return 0;
+}
+
+/**
+ * iscsi_solicit_data_init - initialize first Data-Out
+ * @conn: iscsi connection
+ * @ctask: scsi command task
+ * @r2t: R2T info
+ *
+ * Notes:
+ *     Initialize first Data-Out within this R2T sequence and finds
+ *     proper data_offset within this SCSI command.
+ *
+ *     This function is called with connection lock taken.
+ **/
+static void
+iscsi_solicit_data_init(struct iscsi_conn *conn, struct iscsi_cmd_task *ctask,
+                       struct iscsi_r2t_info *r2t)
+{
+       struct iscsi_data *hdr;
+       struct iscsi_data_task *dtask;
+       struct scsi_cmnd *sc = ctask->sc;
+
+       dtask = mempool_alloc(ctask->datapool, GFP_ATOMIC);
+       BUG_ON(!dtask);
+       hdr = &dtask->hdr;
+       memset(hdr, 0, sizeof(struct iscsi_data));
+       hdr->ttt = r2t->ttt;
+       hdr->datasn = cpu_to_be32(r2t->solicit_datasn);
+       r2t->solicit_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 = r2t->exp_statsn;
+       hdr->offset = cpu_to_be32(r2t->data_offset);
+       if (r2t->data_length > 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, r2t->data_length);
+               r2t->data_count = r2t->data_length;
+               hdr->flags = ISCSI_FLAG_CMD_FINAL;
+       }
+       conn->dataout_pdus_cnt++;
+
+       r2t->sent = 0;
+
+       iscsi_buf_init_hdr(conn, &r2t->headbuf, (char*)hdr,
+                          (u8 *)dtask->hdrext);
+
+       r2t->dtask = dtask;
+
+       if (sc->use_sg) {
+               int i, sg_count = 0;
+               struct scatterlist *sg = sc->request_buffer;
+
+               r2t->sg = NULL;
+               for (i = 0; i < sc->use_sg; i++, sg += 1) {
+                       /* FIXME: prefetch ? */
+                       if (sg_count + sg->length > r2t->data_offset) {
+                               int page_offset;
+
+                               /* sg page found! */
+
+                               /* offset within this page */
+                               page_offset = r2t->data_offset - sg_count;
+
+                               /* fill in this buffer */
+                               iscsi_buf_init_sg(&r2t->sendbuf, sg);
+                               r2t->sendbuf.sg.offset += page_offset;
+                               r2t->sendbuf.sg.length -= page_offset;
+
+                               /* xmit logic will continue with next one */
+                               r2t->sg = sg + 1;
+                               break;
+                       }
+                       sg_count += sg->length;
+               }
+               BUG_ON(r2t->sg == NULL);
+       } else
+               iscsi_buf_init_iov(&ctask->sendbuf,
+                           (char*)sc->request_buffer + r2t->data_offset,
+                           r2t->data_count);
+
+       list_add(&dtask->item, &ctask->dataqueue);
+}
+
+/**
+ * iscsi_r2t_rsp - iSCSI R2T Response processing
+ * @conn: iscsi connection
+ * @ctask: scsi command task
+ **/
+static int
+iscsi_r2t_rsp(struct iscsi_conn *conn, struct iscsi_cmd_task *ctask)
+{
+       struct iscsi_r2t_info *r2t;
+       struct iscsi_session *session = conn->session;
+       struct iscsi_r2t_rsp *rhdr = (struct iscsi_r2t_rsp *)conn->in.hdr;
+       int r2tsn = be32_to_cpu(rhdr->r2tsn);
+       int rc;
+
+       if (conn->in.ahslen)
+               return ISCSI_ERR_AHSLEN;
+
+       if (conn->in.datalen)
+               return ISCSI_ERR_DATALEN;
+
+       if (ctask->exp_r2tsn && ctask->exp_r2tsn != r2tsn)
+               return ISCSI_ERR_R2TSN;
+
+       rc = iscsi_check_assign_cmdsn(session, (struct iscsi_nopin*)rhdr);
+       if (rc)
+               return rc;
+
+       /* FIXME: use R2TSN to detect missing R2T */
+
+       /* fill-in new R2T associated with the task */
+       spin_lock(&session->lock);
+       if (!ctask->sc || ctask->mtask ||
+            session->state != ISCSI_STATE_LOGGED_IN) {
+               printk(KERN_INFO "iscsi_tcp: dropping R2T itt %d in "
+                      "recovery...\n", ctask->itt);
+               spin_unlock(&session->lock);
+               return 0;
+       }
+       rc = __kfifo_get(ctask->r2tpool.queue, (void*)&r2t, sizeof(void*));
+       BUG_ON(!rc);
+
+       r2t->exp_statsn = rhdr->statsn;
+       r2t->data_length = be32_to_cpu(rhdr->data_length);
+       if (r2t->data_length == 0 ||
+           r2t->data_length > session->max_burst) {
+               spin_unlock(&session->lock);
+               return ISCSI_ERR_DATALEN;
+       }
+
+       r2t->data_offset = be32_to_cpu(rhdr->data_offset);
+       if (r2t->data_offset + r2t->data_length > ctask->total_length) {
+               spin_unlock(&session->lock);
+               return ISCSI_ERR_DATALEN;
+       }
+
+       r2t->ttt = rhdr->ttt; /* no flip */
+       r2t->solicit_datasn = 0;
+
+       iscsi_solicit_data_init(conn, ctask, r2t);
+
+       ctask->exp_r2tsn = r2tsn + 1;
+       ctask->xmstate |= XMSTATE_SOL_HDR;
+       __kfifo_put(ctask->r2tqueue, (void*)&r2t, sizeof(void*));
+       __kfifo_put(conn->writequeue, (void*)&ctask, sizeof(void*));
+
+       schedule_work(&conn->xmitwork);
+       conn->r2t_pdus_cnt++;
+       spin_unlock(&session->lock);
+
+       return 0;
+}
+
+static int
+iscsi_hdr_recv(struct iscsi_conn *conn)
+{
+       int rc = 0;
+       struct iscsi_hdr *hdr;
+       struct iscsi_cmd_task *ctask;
+       struct iscsi_session *session = conn->session;
+       uint32_t cdgst, rdgst = 0;
+
+       hdr = conn->in.hdr;
+
+       /* verify PDU length */
+       conn->in.datalen = ntoh24(hdr->dlength);
+       if (conn->in.datalen > conn->max_recv_dlength) {
+               printk(KERN_ERR "iscsi_tcp: datalen %d > %d\n",
+                      conn->in.datalen, conn->max_recv_dlength);
+               return ISCSI_ERR_DATALEN;
+       }
+       conn->data_copied = 0;
+
+       /* read AHS */
+       conn->in.ahslen = hdr->hlength*(4*sizeof(__u16));
+       conn->in.offset += conn->in.ahslen;
+       conn->in.copy -= conn->in.ahslen;
+       if (conn->in.copy < 0) {
+               printk(KERN_ERR "iscsi_tcp: can't handle AHS with length "
+                      "%d bytes\n", conn->in.ahslen);
+               return ISCSI_ERR_AHSLEN;
+       }
+
+       /* calculate read padding */
+       conn->in.padding = conn->in.datalen & (ISCSI_PAD_LEN-1);
+       if (conn->in.padding) {
+               conn->in.padding = ISCSI_PAD_LEN - conn->in.padding;
+               debug_scsi("read padding %d bytes\n", conn->in.padding);
+       }
+
+       if (conn->hdrdgst_en) {
+               struct scatterlist sg;
+
+               sg_init_one(&sg, (u8 *)hdr,
+                           sizeof(struct iscsi_hdr) + conn->in.ahslen);
+               crypto_digest_digest(conn->rx_tfm, &sg, 1, (u8 *)&cdgst);
+               rdgst = *(uint32_t*)((char*)hdr + sizeof(struct iscsi_hdr) +
+                                    conn->in.ahslen);
+       }
+
+       /* save opcode for later */
+       conn->in.opcode = hdr->opcode;
+
+       /* verify itt (itt encoding: age+cid+itt) */
+       if (hdr->itt != cpu_to_be32(ISCSI_RESERVED_TAG)) {
+               if ((hdr->itt & AGE_MASK) !=
+                               (session->age << AGE_SHIFT)) {
+                       printk(KERN_ERR "iscsi_tcp: received itt %x expected "
+                               "session age (%x)\n", hdr->itt,
+                               session->age & AGE_MASK);
+                       return ISCSI_ERR_BAD_ITT;
+               }
+
+               if ((hdr->itt & CID_MASK) != (conn->id << CID_SHIFT)) {
+                       printk(KERN_ERR "iscsi_tcp: received itt %x, expected "
+                               "CID (%x)\n", hdr->itt, conn->id);
+                       return ISCSI_ERR_BAD_ITT;
+               }
+               conn->in.itt = hdr->itt & ITT_MASK;
+       } else
+               conn->in.itt = hdr->itt;
+
+       debug_tcp("opcode 0x%x offset %d copy %d ahslen %d datalen %d\n",
+                 hdr->opcode, conn->in.offset, conn->in.copy,
+                 conn->in.ahslen, conn->in.datalen);
+
+       if (conn->in.itt < session->cmds_max) {
+               if (conn->hdrdgst_en && cdgst != rdgst) {
+                       printk(KERN_ERR "iscsi_tcp: itt %x: hdrdgst error "
+                              "recv 0x%x calc 0x%x\n", conn->in.itt, rdgst,
+                              cdgst);
+                       return ISCSI_ERR_HDR_DGST;
+               }
+
+               ctask = (struct iscsi_cmd_task *)session->cmds[conn->in.itt];
+
+               if (!ctask->sc) {
+                       printk(KERN_INFO "iscsi_tcp: dropping ctask with "
+                              "itt 0x%x\n", ctask->itt);
+                       conn->in.datalen = 0; /* force drop */
+                       return 0;
+               }
+
+               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;
+               }
+
+               conn->in.ctask = ctask;
+
+               debug_scsi("rsp [op 0x%x cid %d sc %lx itt 0x%x len %d]\n",
+                          hdr->opcode, conn->id, (long)ctask->sc,
+                          ctask->itt, conn->in.datalen);
+
+               switch(conn->in.opcode) {
+               case ISCSI_OP_SCSI_CMD_RSP:
+                       BUG_ON((void*)ctask != ctask->sc->SCp.ptr);
+                       if (ctask->hdr.flags & ISCSI_FLAG_CMD_WRITE)
+                               rc = iscsi_cmd_rsp(conn, ctask);
+                       else if (!conn->in.datalen)
+                               rc = iscsi_cmd_rsp(conn, ctask);
+                       else
+                               /*
+                                * got sense or response data; copying PDU
+                                * Header to the connection's header
+                                * placeholder
+                                */
+                               memcpy(&conn->hdr, hdr,
+                                      sizeof(struct iscsi_hdr));
+                       break;
+               case ISCSI_OP_SCSI_DATA_IN:
+                       BUG_ON((void*)ctask != ctask->sc->SCp.ptr);
+                       /* save flags for non-exceptional status */
+                       conn->in.flags = hdr->flags;
+                       /* save cmd_status for sense data */
+                       conn->in.cmd_status =
+                               ((struct iscsi_data_rsp*)hdr)->cmd_status;
+                       rc = iscsi_data_rsp(conn, ctask);
+                       break;
+               case ISCSI_OP_R2T:
+                       BUG_ON((void*)ctask != ctask->sc->SCp.ptr);
+                       if (ctask->hdr.flags & ISCSI_FLAG_CMD_WRITE &&
+                           ctask->sc->sc_data_direction == DMA_TO_DEVICE)
+                               rc = iscsi_r2t_rsp(conn, ctask);
+                       else
+                               rc = ISCSI_ERR_PROTO;
+                       break;
+               case ISCSI_OP_NOOP_IN:
+               case ISCSI_OP_TEXT_RSP:
+               case ISCSI_OP_LOGOUT_RSP:
+               case ISCSI_OP_ASYNC_EVENT:
+               case ISCSI_OP_REJECT:
+                       rc = iscsi_check_assign_cmdsn(session,
+                                                (struct iscsi_nopin*)hdr);
+                       if (rc)
+                               break;
+
+                       /* update ExpStatSN */
+                       conn->exp_statsn = be32_to_cpu(hdr->statsn) + 1;
+                       if (!conn->in.datalen) {
+                               struct iscsi_mgmt_task *mtask;
+
+                               rc = iscsi_recv_pdu(iscsi_handle(conn), hdr,
+                                                   NULL, 0);
+                               mtask = (struct iscsi_mgmt_task *)
+                                       session->mgmt_cmds[conn->in.itt -
+                                               ISCSI_MGMT_ITT_OFFSET];
+                               if (conn->login_mtask != mtask) {
+                                       spin_lock(&session->lock);
+                                       __kfifo_put(session->mgmtpool.queue,
+                                           (void*)&mtask, sizeof(void*));
+                                       spin_unlock(&session->lock);
+                               }
+                       }
+                       break;
+               default:
+                       rc = ISCSI_ERR_BAD_OPCODE;
+                       break;
+               }
+       } else if (conn->in.itt >= ISCSI_MGMT_ITT_OFFSET &&
+                  conn->in.itt < ISCSI_MGMT_ITT_OFFSET +
+                                       session->mgmtpool_max) {
+               struct iscsi_mgmt_task *mtask = (struct iscsi_mgmt_task *)
+                                       session->mgmt_cmds[conn->in.itt -
+                                               ISCSI_MGMT_ITT_OFFSET];
+
+               debug_scsi("immrsp [op 0x%x cid %d itt 0x%x len %d]\n",
+                          conn->in.opcode, conn->id, mtask->itt,
+                          conn->in.datalen);
+
+               switch(conn->in.opcode) {
+               case ISCSI_OP_LOGIN_RSP:
+               case ISCSI_OP_TEXT_RSP:
+                       rc = iscsi_check_assign_cmdsn(session,
+                                                (struct iscsi_nopin*)hdr);
+                       if (rc)
+                               break;
+
+                       if (!conn->in.datalen) {
+                               rc = iscsi_recv_pdu(iscsi_handle(conn), hdr,
+                                                   NULL, 0);
+                               if (conn->login_mtask != mtask) {
+                                       spin_lock(&session->lock);
+                                       __kfifo_put(session->mgmtpool.queue,
+                                           (void*)&mtask, sizeof(void*));
+                                       spin_unlock(&session->lock);
+                               }
+                       }
+                       break;
+               case ISCSI_OP_SCSI_TMFUNC_RSP:
+                       rc = iscsi_check_assign_cmdsn(session,
+                                                (struct iscsi_nopin*)hdr);
+                       if (rc)
+                               break;
+
+                       if (conn->in.datalen || conn->in.ahslen) {
+                               rc = ISCSI_ERR_PROTO;
+                               break;
+                       }
+                       conn->tmfrsp_pdus_cnt++;
+                       spin_lock(&session->lock);
+                       if (conn->tmabort_state == TMABORT_INITIAL) {
+                               __kfifo_put(session->mgmtpool.queue,
+                                               (void*)&mtask, sizeof(void*));
+                               conn->tmabort_state =
+                                       ((struct iscsi_tm_rsp *)hdr)->
+                                       response == SCSI_TCP_TM_RESP_COMPLETE ?
+                                               TMABORT_SUCCESS:TMABORT_FAILED;
+                               /* unblock eh_abort() */
+                               wake_up(&conn->ehwait);
+                       }
+                       spin_unlock(&session->lock);
+                       break;
+               default:
+                       rc = ISCSI_ERR_BAD_OPCODE;
+                       break;
+               }
+       } else if (conn->in.itt == ISCSI_RESERVED_TAG) {
+               if (conn->in.opcode == ISCSI_OP_NOOP_IN && !conn->in.datalen) {
+                       rc = iscsi_check_assign_cmdsn(session,
+                                                (struct iscsi_nopin*)hdr);
+                       if (!rc)
+                               rc = iscsi_recv_pdu(iscsi_handle(conn),
+                                                   hdr, NULL, 0);
+               }
+               else
+                       rc = ISCSI_ERR_BAD_OPCODE;
+       } else
+               rc = ISCSI_ERR_BAD_ITT;
+
+       return rc;
+}
+
+/**
+ * iscsi_ctask_copy - copy skb bits to the destanation cmd task
+ * @conn: iscsi connection
+ * @ctask: scsi command task
+ * @buf: buffer to copy to
+ * @buf_size: size of buffer
+ * @offset: offset within the buffer
+ *
+ * Notes:
+ *     The function calls skb_copy_bits() and updates per-connection and
+ *     per-cmd byte counters.
+ *
+ *     Read counters (in bytes):
+ *
+ *     conn->in.offset         offset within in progress SKB
+ *     conn->in.copy           left to copy from in progress SKB
+ *                             including padding
+ *     conn->in.copied         copied already from in progress SKB
+ *     conn->data_copied       copied already from in progress buffer
+ *     ctask->sent             total bytes sent up to the MidLayer
+ *     ctask->data_count       left to copy from in progress Data-In
+ *     buf_left                left to copy from in progress buffer
+ **/
+static inline int
+iscsi_ctask_copy(struct iscsi_conn *conn, struct iscsi_cmd_task *ctask,
+               void *buf, int buf_size, int offset)
+{
+       int buf_left = buf_size - (conn->data_copied + offset);
+       int size = min(conn->in.copy, buf_left);
+       int rc;
+
+       size = min(size, ctask->data_count);
+
+       debug_tcp("ctask_copy %d bytes at offset %d copied %d\n",
+              size, conn->in.offset, conn->in.copied);
+
+       BUG_ON(size <= 0);
+       BUG_ON(ctask->sent + size > ctask->total_length);
+
+       rc = skb_copy_bits(conn->in.skb, conn->in.offset,
+                          (char*)buf + (offset + conn->data_copied), size);
+       /* must fit into skb->len */
+       BUG_ON(rc);
+
+       conn->in.offset += size;
+       conn->in.copy -= size;
+       conn->in.copied += size;
+       conn->data_copied += size;
+       ctask->sent += size;
+       ctask->data_count -= size;
+
+       BUG_ON(conn->in.copy < 0);
+       BUG_ON(ctask->data_count < 0);
+
+       if (buf_size != (conn->data_copied + offset)) {
+               if (!ctask->data_count) {
+                       BUG_ON(buf_size - conn->data_copied < 0);
+                       /* done with this PDU */
+                       return buf_size - conn->data_copied;
+               }
+               return -EAGAIN;
+       }
+
+       /* done with this buffer or with both - PDU and buffer */
+       conn->data_copied = 0;
+       return 0;
+}
+
+/**
+ * iscsi_tcp_copy - copy skb bits to the destanation buffer
+ * @conn: iscsi connection
+ * @buf: buffer to copy to
+ * @buf_size: number of bytes to copy
+ *
+ * Notes:
+ *     The function calls skb_copy_bits() and updates per-connection
+ *     byte counters.
+ **/
+static inline int
+iscsi_tcp_copy(struct iscsi_conn *conn, void *buf, int buf_size)
+{
+       int buf_left = buf_size - conn->data_copied;
+       int size = min(conn->in.copy, buf_left);
+       int rc;
+
+       debug_tcp("tcp_copy %d bytes at offset %d copied %d\n",
+              size, conn->in.offset, conn->data_copied);
+       BUG_ON(size <= 0);
+
+       rc = skb_copy_bits(conn->in.skb, conn->in.offset,
+                          (char*)buf + conn->data_copied, size);
+       BUG_ON(rc);
+
+       conn->in.offset += size;
+       conn->in.copy -= size;
+       conn->in.copied += size;
+       conn->data_copied += size;
+
+       if (buf_size != conn->data_copied)
+               return -EAGAIN;
+
+       return 0;
+}
+
+static inline void
+partial_sg_digest_update(struct iscsi_conn *conn, struct scatterlist *sg,
+                        int offset, int length)
+{
+       struct scatterlist temp;
+
+       memcpy(&temp, sg, sizeof(struct scatterlist));
+       temp.offset = offset;
+       temp.length = length;
+       crypto_digest_update(conn->data_rx_tfm, &temp, 1);
+}
+
+static int iscsi_scsi_data_in(struct iscsi_conn *conn)
+{
+       struct iscsi_cmd_task *ctask = conn->in.ctask;
+       struct scsi_cmnd *sc = ctask->sc;
+       struct scatterlist tmp, *sg;
+       int i, offset, rc = 0;
+
+       BUG_ON((void*)ctask != sc->SCp.ptr);
+
+       /*
+        * copying Data-In into the Scsi_Cmnd
+        */
+       if (!sc->use_sg) {
+               i = ctask->data_count;
+               rc = iscsi_ctask_copy(conn, ctask, sc->request_buffer,
+                                     sc->request_bufflen, ctask->data_offset);
+               if (rc == -EAGAIN)
+                       return rc;
+               if (conn->datadgst_en) {
+                       sg_init_one(&tmp, sc->request_buffer, i);
+                       crypto_digest_update(conn->data_rx_tfm, &tmp, 1);
+               }
+               rc = 0;
+               goto done;
+       }
+
+       offset = ctask->data_offset;
+       sg = sc->request_buffer;
+
+       if (ctask->data_offset)
+               for (i = 0; i < ctask->sg_count; i++)
+                       offset -= sg[i].length;
+       /* we've passed through partial sg*/
+       if (offset < 0)
+               offset = 0;
+
+       for (i = ctask->sg_count; i < sc->use_sg; i++) {
+               char *dest;
+
+               dest = kmap_atomic(sg[i].page, KM_SOFTIRQ0);
+               rc = iscsi_ctask_copy(conn, ctask, dest + sg[i].offset,
+                                     sg[i].length, offset);
+               kunmap_atomic(dest, KM_SOFTIRQ0);
+               if (rc == -EAGAIN)
+                       /* continue with the next SKB/PDU */
+                       return rc;
+               if (!rc) {
+                       if (conn->datadgst_en) {
+                               if (!offset)
+                                       crypto_digest_update(conn->data_rx_tfm,
+                                                            &sg[i], 1);
+                               else
+                                       partial_sg_digest_update(conn, &sg[i],
+                                                       sg[i].offset + offset,
+                                                       sg[i].length - offset);
+                       }
+                       offset = 0;
+                       ctask->sg_count++;
+               }
+
+               if (!ctask->data_count) {
+                       if (rc && conn->datadgst_en)
+                               /*
+                                * data-in is complete, but buffer not...
+                                */
+                               partial_sg_digest_update(conn, &sg[i],
+                                               sg[i].offset, sg[i].length-rc);
+                       rc = 0;
+                       break;
+               }
+
+               if (!conn->in.copy)
+                       return -EAGAIN;
+       }
+       BUG_ON(ctask->data_count);
+
+done:
+       /* check for non-exceptional status */
+       if (conn->in.flags & ISCSI_FLAG_DATA_STATUS) {
+               debug_scsi("done [sc %lx res %d itt 0x%x]\n",
+                          (long)sc, sc->result, ctask->itt);
+               conn->scsirsp_pdus_cnt++;
+               iscsi_ctask_cleanup(conn, ctask);
+               sc->scsi_done(sc);
+       }
+
+       return rc;
+}
+
+static int
+iscsi_data_recv(struct iscsi_conn *conn)
+{
+       struct iscsi_session *session = conn->session;
+       int rc = 0;
+
+       switch(conn->in.opcode) {
+       case ISCSI_OP_SCSI_DATA_IN:
+               rc = iscsi_scsi_data_in(conn);
+               break;
+       case ISCSI_OP_SCSI_CMD_RSP: {
+               /*
+                * SCSI Sense Data:
+                * copying the entire Data Segment.
+                */
+               if (iscsi_tcp_copy(conn, conn->data, conn->in.datalen)) {
+                       rc = -EAGAIN;
+                       goto exit;
+               }
+
+               /*
+                * check for sense
+                */
+               conn->in.hdr = &conn->hdr;
+               conn->senselen = (conn->data[0] << 8) | conn->data[1];
+               rc = iscsi_cmd_rsp(conn, conn->in.ctask);
+       }
+       break;
+       case ISCSI_OP_TEXT_RSP:
+       case ISCSI_OP_LOGIN_RSP:
+       case ISCSI_OP_NOOP_IN: {
+               struct iscsi_mgmt_task *mtask = NULL;
+
+               if (conn->in.itt != ISCSI_RESERVED_TAG)
+                       mtask = (struct iscsi_mgmt_task *)
+                               session->mgmt_cmds[conn->in.itt -
+                                       ISCSI_MGMT_ITT_OFFSET];
+
+               /*
+                * Collect data segment to the connection's data
+                * placeholder
+                */
+               if (iscsi_tcp_copy(conn, conn->data, conn->in.datalen)) {
+                       rc = -EAGAIN;
+                       goto exit;
+               }
+
+               rc = iscsi_recv_pdu(iscsi_handle(conn), conn->in.hdr,
+                                   conn->data, conn->in.datalen);
+
+               if (mtask && conn->login_mtask != mtask) {
+                       spin_lock(&session->lock);
+                       __kfifo_put(session->mgmtpool.queue, (void*)&mtask,
+                                   sizeof(void*));
+                       spin_unlock(&session->lock);
+               }
+       }
+       break;
+       default:
+               BUG_ON(1);
+       }
+exit:
+       return rc;
+}
+
+/**
+ * iscsi_tcp_data_recv - TCP receive in sendfile fashion
+ * @rd_desc: read descriptor
+ * @skb: socket buffer
+ * @offset: offset in skb
+ * @len: skb->len - offset
+ **/
+static int
+iscsi_tcp_data_recv(read_descriptor_t *rd_desc, struct sk_buff *skb,
+               unsigned int offset, size_t len)
+{
+       int rc;
+       struct iscsi_conn *conn = rd_desc->arg.data;
+       int start = skb_headlen(skb);
+       int processed;
+       char pad[ISCSI_PAD_LEN];
+       struct scatterlist sg;
+
+       /*
+        * Save current SKB and its offset in the corresponding
+        * connection context.
+        */
+       conn->in.copy = start - offset;
+       conn->in.offset = offset;
+       conn->in.skb = skb;
+       conn->in.len = conn->in.copy;
+       BUG_ON(conn->in.copy <= 0);
+       debug_tcp("in %d bytes\n", conn->in.copy);
+
+more:
+       conn->in.copied = 0;
+       rc = 0;
+
+       if (unlikely(conn->suspend_rx)) {
+               debug_tcp("conn %d Rx suspended!\n", conn->id);
+               return 0;
+       }
+
+       if (conn->in_progress == IN_PROGRESS_WAIT_HEADER ||
+           conn->in_progress == IN_PROGRESS_HEADER_GATHER) {
+               rc = iscsi_hdr_extract(conn);
+               if (rc) {
+                      if (rc == -EAGAIN)
+                               goto nomore;
+                      else {
+                               iscsi_conn_failure(conn, rc);
+                               return 0;
+                      }
+               }
+
+               /*
+                * Verify and process incoming PDU header.
+                */
+               rc = iscsi_hdr_recv(conn);
+               if (!rc && conn->in.datalen) {
+                       if (conn->datadgst_en &&
+                           conn->in.opcode == ISCSI_OP_SCSI_DATA_IN) {
+                               BUG_ON(!conn->data_rx_tfm);
+                               crypto_digest_init(conn->data_rx_tfm);
+                       }
+                       conn->in_progress = IN_PROGRESS_DATA_RECV;
+               } else if (rc) {
+                       iscsi_conn_failure(conn, rc);
+                       return 0;
+               }
+       }
+
+       if (conn->in_progress == IN_PROGRESS_DDIGEST_RECV) {
+               debug_tcp("extra data_recv offset %d copy %d\n",
+                         conn->in.offset, conn->in.copy);
+               if (conn->in.opcode == ISCSI_OP_SCSI_DATA_IN) {
+                       uint32_t recv_digest;
+                       skb_copy_bits(conn->in.skb, conn->in.offset,
+                                     &recv_digest, 4);
+                       conn->in.offset += 4;
+                       conn->in.copy -= 4;
+                       if (recv_digest != conn->in.datadgst) {
+                               debug_tcp("iscsi_tcp: data digest error!"
+                                         "0x%x != 0x%x\n", recv_digest,
+                                         conn->in.datadgst);
+                               iscsi_conn_failure(conn, ISCSI_ERR_DATA_DGST);
+                               return 0;
+                       } else {
+                               debug_tcp("iscsi_tcp: data digest match!"
+                                         "0x%x == 0x%x\n", recv_digest,
+                                         conn->in.datadgst);
+                               conn->in_progress = IN_PROGRESS_WAIT_HEADER;
+                       }
+               }
+       }
+
+       if (conn->in_progress == IN_PROGRESS_DATA_RECV && conn->in.copy) {
+
+               debug_tcp("data_recv offset %d copy %d\n",
+                      conn->in.offset, conn->in.copy);
+
+               rc = iscsi_data_recv(conn);
+               if (rc) {
+                       if (rc == -EAGAIN) {
+                               rd_desc->count = conn->in.datalen -
+                                               conn->in.ctask->data_count;
+                               goto again;
+                       }
+                       iscsi_conn_failure(conn, rc);
+                       return 0;
+               }
+               conn->in.copy -= conn->in.padding;
+               conn->in.offset += conn->in.padding;
+               if (conn->datadgst_en &&
+                   conn->in.opcode == ISCSI_OP_SCSI_DATA_IN) {
+                       if (conn->in.padding) {
+                               debug_tcp("padding -> %d\n", conn->in.padding);
+                               memset(pad, 0, conn->in.padding);
+                               sg_init_one(&sg, pad, conn->in.padding);
+                               crypto_digest_update(conn->data_rx_tfm, &sg, 1);
+                       }
+                       crypto_digest_final(conn->data_rx_tfm,
+                                           (u8 *) & conn->in.datadgst);
+                       debug_tcp("rx digest 0x%x\n", conn->in.datadgst);
+                       conn->in_progress = IN_PROGRESS_DDIGEST_RECV;
+               } else
+                       conn->in_progress = IN_PROGRESS_WAIT_HEADER;
+       }
+
+       debug_tcp("f, processed %d from out of %d padding %d\n",
+              conn->in.offset - offset, (int)len, conn->in.padding);
+       BUG_ON(conn->in.offset - offset > len);
+
+       if (conn->in.offset - offset != len) {
+               debug_tcp("continue to process %d bytes\n",
+                      (int)len - (conn->in.offset - offset));
+               goto more;
+       }
+
+nomore:
+       processed = conn->in.offset - offset;
+       BUG_ON(processed == 0);
+       return processed;
+
+again:
+       processed = conn->in.offset - offset;
+       debug_tcp("c, processed %d from out of %d rd_desc_cnt %d\n",
+                 processed, (int)len, (int)rd_desc->count);
+       BUG_ON(processed == 0);
+       BUG_ON(processed > len);
+
+       conn->rxdata_octets += processed;
+       return processed;
+}
+
+static void
+iscsi_tcp_data_ready(struct sock *sk, int flag)
+{
+       struct iscsi_conn *conn = sk->sk_user_data;
+       read_descriptor_t rd_desc;
+
+       read_lock(&sk->sk_callback_lock);
+
+       /* use rd_desc to pass 'conn' to iscsi_tcp_data_recv */
+       rd_desc.arg.data = conn;
+       rd_desc.count = 0;
+       tcp_read_sock(sk, &rd_desc, iscsi_tcp_data_recv);
+
+       read_unlock(&sk->sk_callback_lock);
+}
+
+static void
+iscsi_tcp_state_change(struct sock *sk)
+{
+       struct iscsi_conn *conn;
+       struct iscsi_session *session;
+       void (*old_state_change)(struct sock *);
+
+       read_lock(&sk->sk_callback_lock);
+
+       conn = (struct iscsi_conn*)sk->sk_user_data;
+       session = conn->session;
+
+       if (sk->sk_state == TCP_CLOSE_WAIT ||
+           sk->sk_state == TCP_CLOSE) {
+               debug_tcp("iscsi_tcp_state_change: TCP_CLOSE|TCP_CLOSE_WAIT\n");
+               iscsi_conn_failure(conn, ISCSI_ERR_CONN_FAILED);
+       }
+
+       old_state_change = conn->old_state_change;
+
+       read_unlock(&sk->sk_callback_lock);
+
+       old_state_change(sk);
+}
+
+/**
+ * iscsi_write_space - Called when more output buffer space is available
+ * @sk: socket space is available for
+ **/
+static void
+iscsi_write_space(struct sock *sk)
+{
+       struct iscsi_conn *conn = (struct iscsi_conn*)sk->sk_user_data;
+       conn->old_write_space(sk);
+       debug_tcp("iscsi_write_space: cid %d\n", conn->id);
+       clear_bit(SUSPEND_BIT, &conn->suspend_tx);
+       schedule_work(&conn->xmitwork);
+}
+
+static void
+iscsi_conn_set_callbacks(struct iscsi_conn *conn)
+{
+       struct sock *sk = conn->sock->sk;
+
+       /* assign new callbacks */
+       write_lock_bh(&sk->sk_callback_lock);
+       sk->sk_user_data = conn;
+       conn->old_data_ready = sk->sk_data_ready;
+       conn->old_state_change = sk->sk_state_change;
+       conn->old_write_space = sk->sk_write_space;
+       sk->sk_data_ready = iscsi_tcp_data_ready;
+       sk->sk_state_change = iscsi_tcp_state_change;
+       sk->sk_write_space = iscsi_write_space;
+       write_unlock_bh(&sk->sk_callback_lock);
+}
+
+static void
+iscsi_conn_restore_callbacks(struct iscsi_conn *conn)
+{
+       struct sock *sk = conn->sock->sk;
+
+       /* restore socket callbacks, see also: iscsi_conn_set_callbacks() */
+       write_lock_bh(&sk->sk_callback_lock);
+       sk->sk_user_data    = NULL;
+       sk->sk_data_ready   = conn->old_data_ready;
+       sk->sk_state_change = conn->old_state_change;
+       sk->sk_write_space  = conn->old_write_space;
+       sk->sk_no_check  = 0;
+       write_unlock_bh(&sk->sk_callback_lock);
+}
+
+/**
+ * iscsi_send - generic send routine
+ * @sk: kernel's socket
+ * @buf: buffer to write from
+ * @size: actual size to write
+ * @flags: socket's flags
+ *
+ * Notes:
+ *     depending on buffer will use tcp_sendpage() or tcp_sendmsg().
+ *     buf->sg.offset == -1 tells us that buffer is non S/G and forces
+ *     to use tcp_sendmsg().
+ */
+static inline int
+iscsi_send(struct socket *sk, struct iscsi_buf *buf, int size, int flags)
+{
+       int res;
+
+       if ((int)buf->sg.offset >= 0) {
+               int offset = buf->sg.offset + buf->sent;
+
+               /* tcp_sendpage */
+               res = sk->ops->sendpage(sk, buf->sg.page, offset, size, flags);
+       } else {
+               struct msghdr msg;
+
+               buf->iov.iov_base = iscsi_buf_iov_base(buf);
+               buf->iov.iov_len = size;
+
+               memset(&msg, 0, sizeof(struct msghdr));
+
+               /* tcp_sendmsg */
+               res = kernel_sendmsg(sk, &msg, &buf->iov, 1, size);
+       }
+
+       return res;
+}
+
+/**
+ * iscsi_sendhdr - send PDU Header via tcp_sendpage()
+ * @conn: iscsi connection
+ * @buf: buffer to write from
+ * @datalen: lenght of data to be sent after the header
+ *
+ * Notes:
+ *     (Tx, Fast Path)
+ **/
+static inline int
+iscsi_sendhdr(struct iscsi_conn *conn, struct iscsi_buf *buf, int datalen)
+{
+       struct socket *sk = conn->sock;
+       int flags = 0; /* MSG_DONTWAIT; */
+       int res, size;
+
+       size = buf->sg.length - buf->sent;
+       BUG_ON(buf->sent + size > buf->sg.length);
+       if (buf->sent + size != buf->sg.length || datalen)
+               flags |= MSG_MORE;
+
+       res = iscsi_send(sk, buf, size, flags);
+       debug_tcp("sendhdr %d bytes, sent %d res %d\n", size, buf->sent, res);
+       if (res >= 0) {
+               conn->txdata_octets += res;
+               buf->sent += res;
+               if (size != res)
+                       return -EAGAIN;
+               return 0;
+       } else if (res == -EAGAIN) {
+               conn->sendpage_failures_cnt++;
+               set_bit(SUSPEND_BIT, &conn->suspend_tx);
+       } else if (res == -EPIPE)
+               iscsi_conn_failure(conn, ISCSI_ERR_CONN_FAILED);
+
+       return res;
+}
+
+/**
+ * iscsi_sendpage - send one page of iSCSI Data-Out.
+ * @conn: iscsi connection
+ * @buf: buffer to write from
+ * @count: remaining data
+ * @sent: number of bytes sent
+ *
+ * Notes:
+ *     (Tx, Fast Path)
+ **/
+static inline int
+iscsi_sendpage(struct iscsi_conn *conn, struct iscsi_buf *buf,
+              int *count, int *sent)
+{
+       struct socket *sk = conn->sock;
+       int flags = 0; /* MSG_DONTWAIT; */
+       int res, size;
+
+       size = buf->sg.length - buf->sent;
+       BUG_ON(buf->sent + size > buf->sg.length);
+       if (size > *count)
+               size = *count;
+       if (buf->sent + size != buf->sg.length)
+               flags |= MSG_MORE;
+
+       res = iscsi_send(sk, buf, size, flags);
+       debug_tcp("sendpage: %d bytes, sent %d left %d sent %d res %d\n",
+                 size, buf->sent, *count, *sent, res);
+       if (res >= 0) {
+               conn->txdata_octets += res;
+               buf->sent += res;
+               *count -= res;
+               *sent += res;
+               if (size != res)
+                       return -EAGAIN;
+               return 0;
+       } else if (res == -EAGAIN) {
+               conn->sendpage_failures_cnt++;
+               set_bit(SUSPEND_BIT, &conn->suspend_tx);
+       } else if (res == -EPIPE)
+               iscsi_conn_failure(conn, ISCSI_ERR_CONN_FAILED);
+
+       return res;
+}
+
+static inline void
+iscsi_data_digest_init(struct iscsi_conn *conn, struct iscsi_cmd_task *ctask)
+{
+       BUG_ON(!conn->data_tx_tfm);
+       crypto_digest_init(conn->data_tx_tfm);
+       ctask->digest_count = 4;
+}
+
+static inline void
+iscsi_buf_data_digest_update(struct iscsi_conn *conn, struct iscsi_buf *buf)
+{
+       struct scatterlist sg;
+
+       if (buf->sg.offset != -1)
+               crypto_digest_update(conn->data_tx_tfm, &buf->sg, 1);
+       else {
+               sg_init_one(&sg, (char *)buf->sg.page, buf->sg.length);
+               crypto_digest_update(conn->data_tx_tfm, &sg, 1);
+       }
+}
+
+static inline int
+iscsi_digest_final_send(struct iscsi_conn *conn, struct iscsi_cmd_task *ctask,
+                       struct iscsi_buf *buf, uint32_t *digest, int final)
+{
+       int rc = 0;
+       int sent = 0;
+
+       if (final)
+               crypto_digest_final(conn->data_tx_tfm, (u8*)digest);
+
+       iscsi_buf_init_virt(buf, (char*)digest, 4);
+       rc = iscsi_sendpage(conn, buf, &ctask->digest_count, &sent);
+       if (rc) {
+               ctask->datadigest = *digest;
+               ctask->xmstate |= XMSTATE_DATA_DIGEST;
+       } else
+               ctask->digest_count = 4;
+       return rc;
+}
+
+/**
+ * iscsi_solicit_data_cont - initialize next Data-Out
+ * @conn: iscsi connection
+ * @ctask: scsi command task
+ * @r2t: R2T info
+ * @left: bytes left to transfer
+ *
+ * Notes:
+ *     Initialize next Data-Out within this R2T sequence and continue
+ *     to process next Scatter-Gather element(if any) of this SCSI command.
+ *
+ *     Called under connection lock.
+ **/
+static void
+iscsi_solicit_data_cont(struct iscsi_conn *conn, struct iscsi_cmd_task *ctask,
+                       struct iscsi_r2t_info *r2t, int left)
+{
+       struct iscsi_data *hdr;
+       struct iscsi_data_task *dtask;
+       struct scsi_cmnd *sc = ctask->sc;
+       int new_offset;
+
+       dtask = mempool_alloc(ctask->datapool, GFP_ATOMIC);
+       BUG_ON(!dtask);
+       hdr = &dtask->hdr;
+       memset(hdr, 0, sizeof(struct iscsi_data));
+       hdr->ttt = r2t->ttt;
+       hdr->datasn = cpu_to_be32(r2t->solicit_datasn);
+       r2t->solicit_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 = r2t->exp_statsn;
+       new_offset = r2t->data_offset + r2t->sent;
+       hdr->offset = cpu_to_be32(new_offset);
+       if (left > conn->max_xmit_dlength) {
+               hton24(hdr->dlength, conn->max_xmit_dlength);
+               r2t->data_count = conn->max_xmit_dlength;
+       } else {
+               hton24(hdr->dlength, left);
+               r2t->data_count = left;
+               hdr->flags = ISCSI_FLAG_CMD_FINAL;
+       }
+       conn->dataout_pdus_cnt++;
+
+       iscsi_buf_init_hdr(conn, &r2t->headbuf, (char*)hdr,
+                          (u8 *)dtask->hdrext);
+
+       r2t->dtask = dtask;
+
+       if (sc->use_sg && !iscsi_buf_left(&r2t->sendbuf)) {
+               BUG_ON(ctask->bad_sg == r2t->sg);
+               iscsi_buf_init_sg(&r2t->sendbuf, r2t->sg);
+               r2t->sg += 1;
+       } else
+               iscsi_buf_init_iov(&ctask->sendbuf,
+                           (char*)sc->request_buffer + new_offset,
+                           r2t->data_count);
+
+       list_add(&dtask->item, &ctask->dataqueue);
+}
+
+static void
+iscsi_unsolicit_data_init(struct iscsi_conn *conn, struct iscsi_cmd_task *ctask)
+{
+       struct iscsi_data *hdr;
+       struct iscsi_data_task *dtask;
+
+       dtask = mempool_alloc(ctask->datapool, GFP_ATOMIC);
+       BUG_ON(!dtask);
+       hdr = &dtask->hdr;
+       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 -
+                                 ctask->r2t_data_count -
+                                 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;
+       }
+
+       iscsi_buf_init_hdr(conn, &ctask->headbuf, (char*)hdr,
+                          (u8 *)dtask->hdrext);
+
+       list_add(&dtask->item, &ctask->dataqueue);
+
+       ctask->dtask = dtask;
+}
+
+/**
+ * iscsi_cmd_init - Initialize iSCSI SCSI_READ or SCSI_WRITE commands
+ * @conn: iscsi connection
+ * @ctask: scsi command task
+ * @sc: scsi command
+ **/
+static void
+iscsi_cmd_init(struct iscsi_conn *conn, struct iscsi_cmd_task *ctask,
+               struct scsi_cmnd *sc)
+{
+       struct iscsi_session *session = conn->session;
+
+       BUG_ON(__kfifo_len(ctask->r2tqueue));
+
+       ctask->sc = sc;
+       ctask->conn = conn;
+       ctask->hdr.opcode = ISCSI_OP_SCSI_CMD;
+       ctask->hdr.flags = ISCSI_ATTR_SIMPLE;
+       int_to_scsilun(sc->device->lun, (struct scsi_lun *)ctask->hdr.lun);
+       ctask->hdr.itt = ctask->itt | (conn->id << CID_SHIFT) |
+                        (session->age << AGE_SHIFT);
+       ctask->hdr.data_length = cpu_to_be32(sc->request_bufflen);
+       ctask->hdr.cmdsn = cpu_to_be32(session->cmdsn); session->cmdsn++;
+       ctask->hdr.exp_statsn = cpu_to_be32(conn->exp_statsn);
+       memcpy(ctask->hdr.cdb, sc->cmnd, sc->cmd_len);
+       memset(&ctask->hdr.cdb[sc->cmd_len], 0, MAX_COMMAND_SIZE - sc->cmd_len);
+
+       ctask->mtask = NULL;
+       ctask->sent = 0;
+       ctask->sg_count = 0;
+
+       ctask->total_length = sc->request_bufflen;
+
+       if (sc->sc_data_direction == DMA_TO_DEVICE) {
+               ctask->exp_r2tsn = 0;
+               ctask->hdr.flags |= ISCSI_FLAG_CMD_WRITE;
+               BUG_ON(ctask->total_length == 0);
+               if (sc->use_sg) {
+                       struct scatterlist *sg = sc->request_buffer;
+
+                       iscsi_buf_init_sg(&ctask->sendbuf,
+                                         &sg[ctask->sg_count++]);
+                       ctask->sg = sg;
+                       ctask->bad_sg = sg + sc->use_sg;
+               } else {
+                       iscsi_buf_init_iov(&ctask->sendbuf, sc->request_buffer,
+                                       sc->request_bufflen);
+               }
+
+               /*
+                * 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;
+               ctask->xmstate = XMSTATE_W_HDR;
+               /* calculate write padding */
+               ctask->pad_count = ctask->total_length & (ISCSI_PAD_LEN-1);
+               if (ctask->pad_count) {
+                       ctask->pad_count = ISCSI_PAD_LEN - ctask->pad_count;
+                       debug_scsi("write padding %d bytes\n",
+                               ctask->pad_count);
+                       ctask->xmstate |= XMSTATE_W_PAD;
+               }
+               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);
+                       ctask->xmstate |= XMSTATE_IMM_DATA;
+               } 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->xmstate |= XMSTATE_UNS_HDR | XMSTATE_UNS_INIT;
+
+               ctask->r2t_data_count = ctask->total_length -
+                                   ctask->imm_count -
+                                   ctask->unsol_count;
+
+               debug_scsi("cmd [itt %x total %d imm %d imm_data %d "
+                          "r2t_data %d]\n",
+                          ctask->itt, ctask->total_length, ctask->imm_count,
+                          ctask->unsol_count, ctask->r2t_data_count);
+       } else {
+               ctask->hdr.flags |= ISCSI_FLAG_CMD_FINAL;
+               if (sc->sc_data_direction == DMA_FROM_DEVICE)
+                       ctask->hdr.flags |= ISCSI_FLAG_CMD_READ;
+               ctask->datasn = 0;
+               ctask->xmstate = XMSTATE_R_HDR;
+               zero_data(ctask->hdr.dlength);
+       }
+
+       iscsi_buf_init_hdr(conn, &ctask->headbuf, (char*)&ctask->hdr,
+                           (u8 *)ctask->hdrext);
+       conn->scsicmd_pdus_cnt++;
+}
+
+/**
+ * iscsi_mtask_xmit - xmit management(immediate) task
+ * @conn: iscsi connection
+ * @mtask: task management task
+ *
+ * Notes:
+ *     The function can return -EAGAIN in which case caller must
+ *     call it again later, or recover. '0' return code means successful
+ *     xmit.
+ *
+ *     Management xmit state machine consists of two states:
+ *             IN_PROGRESS_IMM_HEAD - PDU Header xmit in progress
+ *             IN_PROGRESS_IMM_DATA - PDU Data xmit in progress
+ **/
+static int
+iscsi_mtask_xmit(struct iscsi_conn *conn, struct iscsi_mgmt_task *mtask)
+{
+
+       debug_scsi("mtask deq [cid %d state %x itt 0x%x]\n",
+               conn->id, mtask->xmstate, mtask->itt);
+
+       if (mtask->xmstate & XMSTATE_IMM_HDR) {
+               mtask->xmstate &= ~XMSTATE_IMM_HDR;
+               if (mtask->data_count)
+                       mtask->xmstate |= XMSTATE_IMM_DATA;
+               if (iscsi_sendhdr(conn, &mtask->headbuf, mtask->data_count)) {
+                       mtask->xmstate |= XMSTATE_IMM_HDR;
+                       if (mtask->data_count)
+                               mtask->xmstate &= ~XMSTATE_IMM_DATA;
+                       return -EAGAIN;
+               }
+       }
+
+       if (mtask->xmstate & XMSTATE_IMM_DATA) {
+               BUG_ON(!mtask->data_count);
+               mtask->xmstate &= ~XMSTATE_IMM_DATA;
+               /* FIXME: implement.
+                * Virtual buffer could be spreaded across multiple pages...
+                */
+               do {
+                       if (iscsi_sendpage(conn, &mtask->sendbuf,
+                                  &mtask->data_count, &mtask->sent)) {
+                               mtask->xmstate |= XMSTATE_IMM_DATA;
+                               return -EAGAIN;
+                       }
+               } while (mtask->data_count);
+       }
+
+       BUG_ON(mtask->xmstate != XMSTATE_IDLE);
+       return 0;
+}
+
+static inline int
+handle_xmstate_r_hdr(struct iscsi_conn *conn, struct iscsi_cmd_task *ctask)
+{
+       ctask->xmstate &= ~XMSTATE_R_HDR;
+       if (!iscsi_sendhdr(conn, &ctask->headbuf, 0)) {
+               BUG_ON(ctask->xmstate != XMSTATE_IDLE);
+               return 0; /* wait for Data-In */
+       }
+       ctask->xmstate |= XMSTATE_R_HDR;
+       return -EAGAIN;
+}
+
+static inline int
+handle_xmstate_w_hdr(struct iscsi_conn *conn, struct iscsi_cmd_task *ctask)
+{
+       ctask->xmstate &= ~XMSTATE_W_HDR;
+       if (iscsi_sendhdr(conn, &ctask->headbuf, ctask->imm_count)) {
+               ctask->xmstate |= XMSTATE_W_HDR;
+               return -EAGAIN;
+       }
+       return 0;
+}
+
+static inline int
+handle_xmstate_data_digest(struct iscsi_conn *conn,
+                          struct iscsi_cmd_task *ctask)
+{
+       ctask->xmstate &= ~XMSTATE_DATA_DIGEST;
+       debug_tcp("resent data digest 0x%x\n", ctask->datadigest);
+       if (iscsi_digest_final_send(conn, ctask, &ctask->immbuf,
+                                   &ctask->datadigest, 0)) {
+               ctask->xmstate |= XMSTATE_DATA_DIGEST;
+               debug_tcp("resent data digest 0x%x fail!\n",
+                         ctask->datadigest);
+               return -EAGAIN;
+       }
+       return 0;
+}
+
+static inline int
+handle_xmstate_imm_data(struct iscsi_conn *conn, struct iscsi_cmd_task *ctask)
+{
+       BUG_ON(!ctask->imm_count);
+       ctask->xmstate &= ~XMSTATE_IMM_DATA;
+
+       if (conn->datadgst_en) {
+               iscsi_data_digest_init(conn, ctask);
+               ctask->immdigest = 0;
+       }
+
+       for (;;) {
+               if (iscsi_sendpage(conn, &ctask->sendbuf, &ctask->imm_count,
+                                  &ctask->sent)) {
+                       ctask->xmstate |= XMSTATE_IMM_DATA;
+                       if (conn->datadgst_en) {
+                               crypto_digest_final(conn->data_tx_tfm,
+                                               (u8*)&ctask->immdigest);
+                               debug_tcp("tx imm sendpage fail 0x%x\n",
+                                         ctask->datadigest);
+                       }
+                       return -EAGAIN;
+               }
+               if (conn->datadgst_en)
+                       iscsi_buf_data_digest_update(conn, &ctask->sendbuf);
+
+               if (!ctask->imm_count)
+                       break;
+               iscsi_buf_init_sg(&ctask->sendbuf,
+                                 &ctask->sg[ctask->sg_count++]);
+       }
+
+       if (conn->datadgst_en && !(ctask->xmstate & XMSTATE_W_PAD)) {
+               if (iscsi_digest_final_send(conn, ctask, &ctask->immbuf,
+                                           &ctask->immdigest, 1)) {
+                       debug_tcp("sending imm digest 0x%x fail!\n",
+                                 ctask->immdigest);
+                       return -EAGAIN;
+               }
+               debug_tcp("sending imm digest 0x%x\n", ctask->immdigest);
+       }
+
+       return 0;
+}
+
+static inline int
+handle_xmstate_uns_hdr(struct iscsi_conn *conn, struct iscsi_cmd_task *ctask)
+{
+       struct iscsi_data_task *dtask;
+
+       ctask->xmstate |= XMSTATE_UNS_DATA;
+       if (ctask->xmstate & XMSTATE_UNS_INIT) {
+               iscsi_unsolicit_data_init(conn, ctask);
+               BUG_ON(!ctask->dtask);
+               dtask = ctask->dtask;
+
+               ctask->xmstate &= ~XMSTATE_UNS_INIT;
+       }
+       if (iscsi_sendhdr(conn, &ctask->headbuf, ctask->data_count)) {
+               ctask->xmstate &= ~XMSTATE_UNS_DATA;
+               ctask->xmstate |= XMSTATE_UNS_HDR;
+               return -EAGAIN;
+       }
+
+       debug_scsi("uns dout [itt 0x%x dlen %d sent %d]\n",
+                  ctask->itt, ctask->unsol_count, ctask->sent);
+       return 0;
+}
+
+static inline int
+handle_xmstate_uns_data(struct iscsi_conn *conn, struct iscsi_cmd_task *ctask)
+{
+       struct iscsi_data_task *dtask = ctask->dtask;
+
+       BUG_ON(!ctask->data_count);
+       ctask->xmstate &= ~XMSTATE_UNS_DATA;
+
+       if (conn->datadgst_en) {
+               iscsi_data_digest_init(conn, ctask);
+               dtask->digest = 0;
+       }
+
+       for (;;) {
+               int start = ctask->sent;
+
+               if (iscsi_sendpage(conn, &ctask->sendbuf, &ctask->data_count,
+                                  &ctask->sent)) {
+                       ctask->unsol_count -= ctask->sent - start;
+                       ctask->xmstate |= XMSTATE_UNS_DATA;
+                       /* will continue with this ctask later.. */
+                       if (conn->datadgst_en) {
+                               crypto_digest_final(conn->data_tx_tfm,
+                                               (u8 *)&dtask->digest);
+                               debug_tcp("tx uns data fail 0x%x\n",
+                                         dtask->digest);
+                       }
+                       return -EAGAIN;
+               }
+
+               BUG_ON(ctask->sent > ctask->total_length);
+               ctask->unsol_count -= ctask->sent - start;
+
+               /*
+                * XXX:we may run here with un-initial sendbuf.
+                * so pass it
+                */
+               if (conn->datadgst_en && ctask->sent - start > 0)
+                       iscsi_buf_data_digest_update(conn, &ctask->sendbuf);
+
+               if (!ctask->data_count)
+                       break;
+               iscsi_buf_init_sg(&ctask->sendbuf,
+                                 &ctask->sg[ctask->sg_count++]);
+       }
+       BUG_ON(ctask->unsol_count < 0);
+
+       /*
+        * Done with the Data-Out. Next, check if we need
+        * to send another unsolicited Data-Out.
+        */
+       if (ctask->unsol_count) {
+               if (conn->datadgst_en) {
+                       if (iscsi_digest_final_send(conn, ctask,
+                                                   &dtask->digestbuf,
+                                                   &dtask->digest, 1)) {
+                               debug_tcp("send uns digest 0x%x fail\n",
+                                         dtask->digest);
+                               return -EAGAIN;
+                       }
+                       debug_tcp("sending uns digest 0x%x, more uns\n",
+                                 dtask->digest);
+               }
+               ctask->xmstate |= XMSTATE_UNS_INIT;
+               return 1;
+       }
+
+       if (conn->datadgst_en && !(ctask->xmstate & XMSTATE_W_PAD)) {
+               if (iscsi_digest_final_send(conn, ctask,
+                                           &dtask->digestbuf,
+                                           &dtask->digest, 1)) {
+                       debug_tcp("send last uns digest 0x%x fail\n",
+                                  dtask->digest);
+                       return -EAGAIN;
+               }
+               debug_tcp("sending uns digest 0x%x\n",dtask->digest);
+       }
+
+       return 0;
+}
+
+static inline int
+handle_xmstate_sol_data(struct iscsi_conn *conn, struct iscsi_cmd_task *ctask)
+{
+       struct iscsi_session *session = conn->session;
+       struct iscsi_r2t_info *r2t = ctask->r2t;
+       struct iscsi_data_task *dtask = r2t->dtask;
+       int left;
+
+       ctask->xmstate &= ~XMSTATE_SOL_DATA;
+       ctask->dtask = dtask;
+
+       if (conn->datadgst_en) {
+               iscsi_data_digest_init(conn, ctask);
+               dtask->digest = 0;
+       }
+solicit_again:
+       /*
+        * send Data-Out whitnin this R2T sequence.
+        */
+       if (!r2t->data_count)
+               goto data_out_done;
+
+       if (iscsi_sendpage(conn, &r2t->sendbuf, &r2t->data_count, &r2t->sent)) {
+               ctask->xmstate |= XMSTATE_SOL_DATA;
+               /* will continue with this ctask later.. */
+               if (conn->datadgst_en) {
+                       crypto_digest_final(conn->data_tx_tfm,
+                                         (u8 *)&dtask->digest);
+                       debug_tcp("r2t data send fail 0x%x\n", dtask->digest);
+               }
+               return -EAGAIN;
+       }
+
+       BUG_ON(r2t->data_count < 0);
+       if (conn->datadgst_en)
+               iscsi_buf_data_digest_update(conn, &r2t->sendbuf);
+
+       if (r2t->data_count) {
+               BUG_ON(ctask->sc->use_sg == 0);
+               if (!iscsi_buf_left(&r2t->sendbuf)) {
+                       BUG_ON(ctask->bad_sg == r2t->sg);
+                       iscsi_buf_init_sg(&r2t->sendbuf, r2t->sg);
+                       r2t->sg += 1;
+               }
+               goto solicit_again;
+       }
+
+data_out_done:
+       /*
+        * Done with this Data-Out. Next, check if we have
+        * to send another Data-Out for this R2T.
+        */
+       BUG_ON(r2t->data_length - r2t->sent < 0);
+       left = r2t->data_length - r2t->sent;
+       if (left) {
+               if (conn->datadgst_en) {
+                       if (iscsi_digest_final_send(conn, ctask,
+                                                   &dtask->digestbuf,
+                                                   &dtask->digest, 1)) {
+                               debug_tcp("send r2t data digest 0x%x"
+                                         "fail\n", dtask->digest);
+                               return -EAGAIN;
+                       }
+                       debug_tcp("r2t data send digest 0x%x\n",
+                                 dtask->digest);
+               }
+               iscsi_solicit_data_cont(conn, ctask, r2t, left);
+               ctask->xmstate |= XMSTATE_SOL_DATA;
+               ctask->xmstate &= ~XMSTATE_SOL_HDR;
+               return 1;
+       }
+
+       /*
+        * Done with this R2T. Check if there are more
+        * outstanding R2Ts ready to be processed.
+        */
+       BUG_ON(ctask->r2t_data_count - r2t->data_length < 0);
+       if (conn->datadgst_en) {
+               if (iscsi_digest_final_send(conn, ctask, &dtask->digestbuf,
+                                           &dtask->digest, 1)) {
+                       debug_tcp("send last r2t data digest 0x%x"
+                                 "fail\n", dtask->digest);
+                       return -EAGAIN;
+               }
+               debug_tcp("r2t done dout digest 0x%x\n", dtask->digest);
+       }
+
+       ctask->r2t_data_count -= r2t->data_length;
+       ctask->r2t = NULL;
+       spin_lock_bh(&session->lock);
+       __kfifo_put(ctask->r2tpool.queue, (void*)&r2t, sizeof(void*));
+       spin_unlock_bh(&session->lock);
+       if (__kfifo_get(ctask->r2tqueue, (void*)&r2t, sizeof(void*))) {
+               ctask->r2t = r2t;
+               ctask->xmstate |= XMSTATE_SOL_DATA;
+               ctask->xmstate &= ~XMSTATE_SOL_HDR;
+               return 1;
+       }
+
+       return 0;
+}
+
+static inline int
+handle_xmstate_w_pad(struct iscsi_conn *conn, struct iscsi_cmd_task *ctask)
+{
+       struct iscsi_data_task *dtask = ctask->dtask;
+       int sent;
+
+       ctask->xmstate &= ~XMSTATE_W_PAD;
+       iscsi_buf_init_virt(&ctask->sendbuf, (char*)&ctask->pad,
+                           ctask->pad_count);
+       if (iscsi_sendpage(conn, &ctask->sendbuf, &ctask->pad_count, &sent)) {
+               ctask->xmstate |= XMSTATE_W_PAD;
+               return -EAGAIN;
+       }
+
+       if (conn->datadgst_en) {
+               iscsi_buf_data_digest_update(conn, &ctask->sendbuf);
+               /* imm data? */
+               if (!dtask) {
+                       if (iscsi_digest_final_send(conn, ctask, &ctask->immbuf,
+                                                   &ctask->immdigest, 1)) {
+                               debug_tcp("send padding digest 0x%x"
+                                         "fail!\n", ctask->immdigest);
+                               return -EAGAIN;
+                       }
+                       debug_tcp("done with padding, digest 0x%x\n",
+                                 ctask->datadigest);
+               } else {
+                       if (iscsi_digest_final_send(conn, ctask,
+                                                   &dtask->digestbuf,
+                                                   &dtask->digest, 1)) {
+                               debug_tcp("send padding digest 0x%x"
+                                         "fail\n", dtask->digest);
+                               return -EAGAIN;
+                       }
+                       debug_tcp("done with padding, digest 0x%x\n",
+                                 dtask->digest);
+               }
+       }
+
+       return 0;
+}
+
+static int
+iscsi_ctask_xmit(struct iscsi_conn *conn, struct iscsi_cmd_task *ctask)
+{
+       int rc = 0;
+
+       debug_scsi("ctask deq [cid %d xmstate %x itt 0x%x]\n",
+               conn->id, ctask->xmstate, ctask->itt);
+
+       /*
+        * serialize with TMF AbortTask
+        */
+       if (ctask->mtask)
+               return rc;
+
+       if (ctask->xmstate & XMSTATE_R_HDR) {
+               rc = handle_xmstate_r_hdr(conn, ctask);
+               return rc;
+       }
+
+       if (ctask->xmstate & XMSTATE_W_HDR) {
+               rc = handle_xmstate_w_hdr(conn, ctask);
+               if (rc)
+                       return rc;
+       }
+
+       /* XXX: for data digest xmit recover */
+       if (ctask->xmstate & XMSTATE_DATA_DIGEST) {
+               rc = handle_xmstate_data_digest(conn, ctask);
+               if (rc)
+                       return rc;
+       }
+
+       if (ctask->xmstate & XMSTATE_IMM_DATA) {
+               rc = handle_xmstate_imm_data(conn, ctask);
+               if (rc)
+                       return rc;
+       }
+
+       if (ctask->xmstate & XMSTATE_UNS_HDR) {
+               BUG_ON(!ctask->unsol_count);
+               ctask->xmstate &= ~XMSTATE_UNS_HDR;
+unsolicit_head_again:
+               rc = handle_xmstate_uns_hdr(conn, ctask);
+               if (rc)
+                       return rc;
+       }
+
+       if (ctask->xmstate & XMSTATE_UNS_DATA) {
+               rc = handle_xmstate_uns_data(conn, ctask);
+               if (rc == 1)
+                       goto unsolicit_head_again;
+               else if (rc)
+                       return rc;
+               goto done;
+       }
+
+       if (ctask->xmstate & XMSTATE_SOL_HDR) {
+               struct iscsi_r2t_info *r2t;
+
+               ctask->xmstate &= ~XMSTATE_SOL_HDR;
+               ctask->xmstate |= XMSTATE_SOL_DATA;
+               if (!ctask->r2t)
+                       __kfifo_get(ctask->r2tqueue, (void*)&ctask->r2t,
+                                   sizeof(void*));
+solicit_head_again:
+               r2t = ctask->r2t;
+
+               if (iscsi_sendhdr(conn, &r2t->headbuf, r2t->data_count)) {
+                       ctask->xmstate &= ~XMSTATE_SOL_DATA;
+                       ctask->xmstate |= XMSTATE_SOL_HDR;
+                       return -EAGAIN;
+               }
+
+               debug_scsi("sol dout [dsn %d itt 0x%x dlen %d sent %d]\n",
+                       r2t->solicit_datasn - 1, ctask->itt, r2t->data_count,
+                       r2t->sent);
+       }
+
+       if (ctask->xmstate & XMSTATE_SOL_DATA) {
+               rc = handle_xmstate_sol_data(conn, ctask);
+               if (rc == 1)
+                       goto solicit_head_again;
+               if (rc)
+                       return rc;
+       }
+
+done:
+       /*
+        * Last thing to check is whether we need to send write
+        * padding. Note that we check for xmstate equality, not just the bit.
+        */
+       if (ctask->xmstate == XMSTATE_W_PAD)
+               rc = handle_xmstate_w_pad(conn, ctask);
+
+       return rc;
+}
+
+/**
+ * iscsi_data_xmit - xmit any command into the scheduled connection
+ * @conn: iscsi connection
+ *
+ * Notes:
+ *     The function can return -EAGAIN in which case the caller must
+ *     re-schedule it again later or recover. '0' return code means
+ *     successful xmit.
+ **/
+static int
+iscsi_data_xmit(struct iscsi_conn *conn)
+{
+       if (unlikely(conn->suspend_tx)) {
+               debug_tcp("conn %d Tx suspended!\n", conn->id);
+               return 0;
+       }
+
+       /*
+        * 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 (iscsi_ctask_xmit(conn, conn->ctask))
+                       goto again;
+               /* done with this in-progress ctask */
+               conn->ctask = NULL;
+       }
+       if (conn->mtask) {
+               if (iscsi_mtask_xmit(conn, conn->mtask))
+                       goto again;
+               /* done with this in-progress mtask */
+               conn->mtask = NULL;
+       }
+
+       /* process immediate first */
+        if (unlikely(__kfifo_len(conn->immqueue))) {
+               struct iscsi_session *session = conn->session;
+               while (__kfifo_get(conn->immqueue, (void*)&conn->mtask,
+                                  sizeof(void*))) {
+                       if (iscsi_mtask_xmit(conn, conn->mtask))
+                               goto again;
+
+                       if (conn->mtask->hdr.itt ==
+                                       cpu_to_be32(ISCSI_RESERVED_TAG)) {
+                               spin_lock_bh(&session->lock);
+                               __kfifo_put(session->mgmtpool.queue,
+                                           (void*)&conn->mtask, sizeof(void*));
+                               spin_unlock_bh(&session->lock);
+                       }
+               }
+               /* done with this mtask */
+               conn->mtask = NULL;
+       }
+
+       /* process write queue */
+       while (__kfifo_get(conn->writequeue, (void*)&conn->ctask,
+                          sizeof(void*))) {
+               if (iscsi_ctask_xmit(conn, conn->ctask))
+                       goto again;
+       }
+
+       /* process command queue */
+       while (__kfifo_get(conn->xmitqueue, (void*)&conn->ctask,
+                          sizeof(void*))) {
+               if (iscsi_ctask_xmit(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))) {
+               struct iscsi_session *session = conn->session;
+
+               while (__kfifo_get(conn->mgmtqueue, (void*)&conn->mtask,
+                                  sizeof(void*))) {
+                       if (iscsi_mtask_xmit(conn, conn->mtask))
+                               goto again;
+
+                       if (conn->mtask->hdr.itt ==
+                                       cpu_to_be32(ISCSI_RESERVED_TAG)) {
+                               spin_lock_bh(&session->lock);
+                               __kfifo_put(session->mgmtpool.queue,
+                                           (void*)&conn->mtask,
+                                           sizeof(void*));
+                               spin_unlock_bh(&session->lock);
+                       }
+               }
+               /* 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.
+        */
+       down(&conn->xmitsema);
+       if (iscsi_data_xmit(conn))
+               schedule_work(&conn->xmitwork);
+       up(&conn->xmitsema);
+}
+
+#define FAILURE_BAD_HOST               1
+#define FAILURE_SESSION_FAILED         2
+#define FAILURE_SESSION_FREED          3
+#define FAILURE_WINDOW_CLOSED          4
+#define FAILURE_SESSION_TERMINATE      5
+
+static 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 = NULL;
+       struct iscsi_cmd_task *ctask = NULL;
+
+       sc->scsi_done = done;
+       sc->result = 0;
+
+       host = sc->device->host;
+       session = iscsi_hostdata(host->hostdata);
+       BUG_ON(host != session->host);
+
+       spin_lock(&session->lock);
+
+       if (session->state != ISCSI_STATE_LOGGED_IN) {
+               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*));
+       BUG_ON(ctask->sc);
+
+       sc->SCp.phase = session->age;
+       sc->SCp.ptr = (char*)ctask;
+       iscsi_cmd_init(conn, ctask, sc);
+
+       __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);
+
+        if (!in_interrupt() && !down_trylock(&conn->xmitsema)) {
+               spin_unlock_irq(host->host_lock);
+               if (iscsi_data_xmit(conn))
+                       schedule_work(&conn->xmitwork);
+               up(&conn->xmitsema);
+               spin_lock_irq(host->host_lock);
+       } else
+               schedule_work(&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->sense_buffer[0] = 0x70;
+       sc->sense_buffer[2] = NOT_READY;
+       sc->sense_buffer[7] = 0x6;
+       sc->sense_buffer[12] = 0x08;
+       sc->sense_buffer[13] = 0x00;
+       sc->result = (DID_NO_CONNECT << 16);
+       sc->resid = sc->request_bufflen;
+       sc->scsi_done(sc);
+       return 0;
+}
+
+static 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;
+}
+
+static 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);
+}
+
+static iscsi_connh_t
+iscsi_conn_create(iscsi_sessionh_t sessionh, uint32_t conn_idx)
+{
+       struct iscsi_session *session = iscsi_ptr(sessionh);
+       struct iscsi_conn *conn = NULL;
+
+       conn = kmalloc(sizeof(struct iscsi_conn), GFP_KERNEL);
+       if (conn == NULL)
+               goto conn_alloc_fail;
+       memset(conn, 0, sizeof(struct iscsi_conn));
+
+       conn->c_stage = ISCSI_CONN_INITIAL_STAGE;
+       conn->in_progress = IN_PROGRESS_WAIT_HEADER;
+       conn->id = conn_idx;
+       conn->exp_statsn = 0;
+       conn->tmabort_state = TMABORT_INITIAL;
+
+       /* initial operational parameters */
+       conn->hdr_size = sizeof(struct iscsi_hdr);
+       conn->data_size = DEFAULT_MAX_RECV_DATA_SEGMENT_LENGTH;
+       conn->max_recv_dlength = DEFAULT_MAX_RECV_DATA_SEGMENT_LENGTH;
+
+       spin_lock_init(&conn->lock);
+
+       /* 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 write response PDU commands queue */
+       conn->writequeue = kfifo_alloc(session->cmds_max * sizeof(void*),
+                                       GFP_KERNEL, NULL);
+       if (conn->writequeue == ERR_PTR(-ENOMEM))
+               goto writequeue_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);
+
+       /* allocate initial PDU receive place holder */
+       if (conn->data_size <= PAGE_SIZE)
+               conn->data = kmalloc(conn->data_size, GFP_KERNEL);
+       else
+               conn->data = (void*)__get_free_pages(GFP_KERNEL,
+                                       get_order(conn->data_size));
+       if (!conn->data)
+               goto max_recv_dlenght_alloc_fail;
+
+       init_timer(&conn->tmabort_timer);
+       init_MUTEX(&conn->xmitsema);
+       init_waitqueue_head(&conn->ehwait);
+
+       return iscsi_handle(conn);
+
+max_recv_dlenght_alloc_fail:
+       spin_lock_bh(&session->lock);
+       __kfifo_put(session->mgmtpool.queue, (void*)&conn->login_mtask,
+                   sizeof(void*));
+       spin_unlock_bh(&session->lock);
+login_mtask_alloc_fail:
+       kfifo_free(conn->mgmtqueue);
+mgmtqueue_alloc_fail:
+       kfifo_free(conn->immqueue);
+immqueue_alloc_fail:
+       kfifo_free(conn->writequeue);
+writequeue_alloc_fail:
+       kfifo_free(conn->xmitqueue);
+xmitqueue_alloc_fail:
+       kfree(conn);
+conn_alloc_fail:
+       return iscsi_handle(NULL);
+}
+
+static void
+iscsi_conn_destroy(iscsi_connh_t connh)
+{
+       struct iscsi_conn *conn = iscsi_ptr(connh);
+       struct iscsi_session *session = conn->session;
+
+       down(&conn->xmitsema);
+       set_bit(SUSPEND_BIT, &conn->suspend_tx);
+       if (conn->c_stage == ISCSI_CONN_INITIAL_STAGE && conn->sock) {
+               struct sock *sk = conn->sock->sk;
+
+               /*
+                * conn_start() has never been called!
+                * need to cleanup the socket.
+                */
+               write_lock_bh(&sk->sk_callback_lock);
+               set_bit(SUSPEND_BIT, &conn->suspend_rx);
+               write_unlock_bh(&sk->sk_callback_lock);
+
+               sock_hold(conn->sock->sk);
+               iscsi_conn_restore_callbacks(conn);
+               sock_put(conn->sock->sk);
+               sock_release(conn->sock);
+               conn->sock = NULL;
+       }
+
+       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);
+
+       up(&conn->xmitsema);
+
+       /*
+        * Block until all in-progress commands for this connection
+        * time out or fail.
+        */
+       for (;;) {
+               spin_lock_bh(&conn->lock);
+               if (!session->host->host_busy) { /* OK for ERL == 0 */
+                       spin_unlock_bh(&conn->lock);
+                       break;
+               }
+               spin_unlock_bh(&conn->lock);
+               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);
+       }
+
+       /* now free crypto */
+       if (conn->hdrdgst_en || conn->datadgst_en) {
+               if (conn->tx_tfm)
+                       crypto_free_tfm(conn->tx_tfm);
+               if (conn->rx_tfm)
+                       crypto_free_tfm(conn->rx_tfm);
+               if (conn->data_tx_tfm)
+                       crypto_free_tfm(conn->data_tx_tfm);
+               if (conn->data_rx_tfm)
+                       crypto_free_tfm(conn->data_rx_tfm);
+       }
+
+       /* free conn->data, size = MaxRecvDataSegmentLength */
+       if (conn->data_size <= PAGE_SIZE)
+               kfree(conn->data);
+       else
+               free_pages((unsigned long)conn->data,
+                                       get_order(conn->data_size));
+
+       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)
+               /* none 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->writequeue);
+       kfifo_free(conn->immqueue);
+       kfifo_free(conn->mgmtqueue);
+       kfree(conn);
+}
+
+static int
+iscsi_conn_bind(iscsi_sessionh_t sessionh, iscsi_connh_t connh,
+               uint32_t transport_fd, int is_leading)
+{
+       struct iscsi_session *session = iscsi_ptr(sessionh);
+       struct iscsi_conn *tmp = ERR_PTR(-EEXIST), *conn = iscsi_ptr(connh);
+       struct sock *sk;
+       struct socket *sock;
+       int err;
+
+       /* lookup for existing socket */
+       sock = sockfd_lookup(transport_fd, &err);
+       if (!sock) {
+               printk(KERN_ERR "iscsi_tcp: sockfd_lookup failed %d\n", err);
+               return -EEXIST;
+       }
+
+       /* 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 (conn->stop_stage != STOP_CONN_SUSPEND) {
+               /* bind iSCSI connection and socket */
+               conn->sock = sock;
+
+               /* setup Socket parameters */
+               sk = sock->sk;
+               sk->sk_reuse = 1;
+               sk->sk_sndtimeo = 15 * HZ; /* FIXME: make it configurable */
+               sk->sk_allocation = GFP_ATOMIC;
+
+               /* FIXME: disable Nagle's algorithm */
+
+               /*
+                * Intercept TCP callbacks for sendfile like receive
+                * processing.
+                */
+               iscsi_conn_set_callbacks(conn);
+
+               /*
+                * set receive state machine into initial state
+                */
+               conn->in_progress = IN_PROGRESS_WAIT_HEADER;
+       }
+
+       if (is_leading)
+               session->leadconn = conn;
+
+       /*
+        * Unblock xmitworker(), Login Phase will pass through.
+        */
+       clear_bit(SUSPEND_BIT, &conn->suspend_rx);
+       clear_bit(SUSPEND_BIT, &conn->suspend_tx);
+
+       return 0;
+}
+
+static int
+iscsi_conn_start(iscsi_connh_t connh)
+{
+       struct iscsi_conn *conn = iscsi_ptr(connh);
+       struct iscsi_session *session = conn->session;
+       struct sock *sk;
+
+       /* FF phase warming up... */
+
+       if (session == NULL) {
+               printk(KERN_ERR "iscsi_tcp: can't start unbound connection\n");
+               return -EPERM;
+       }
+
+       sk = conn->sock->sk;
+
+       write_lock_bh(&sk->sk_callback_lock);
+       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++;
+               wake_up(&conn->ehwait);
+               break;
+       case STOP_CONN_TERM:
+               session->conn_cnt++;
+               conn->stop_stage = 0;
+               break;
+       case STOP_CONN_SUSPEND:
+               conn->stop_stage = 0;
+               clear_bit(SUSPEND_BIT, &conn->suspend_rx);
+               clear_bit(SUSPEND_BIT, &conn->suspend_tx);
+               break;
+       default:
+               break;
+       }
+       spin_unlock_bh(&session->lock);
+       write_unlock_bh(&sk->sk_callback_lock);
+
+       return 0;
+}
+
+static void
+iscsi_conn_stop(iscsi_connh_t connh, int flag)
+{
+       struct iscsi_conn *conn = iscsi_ptr(connh);
+       struct iscsi_session *session = conn->session;
+       struct sock *sk;
+       unsigned long flags;
+
+       BUG_ON(!conn->sock);
+       sk = conn->sock->sk;
+       write_lock_bh(&sk->sk_callback_lock);
+       set_bit(SUSPEND_BIT, &conn->suspend_rx);
+       write_unlock_bh(&sk->sk_callback_lock);
+
+       down(&conn->xmitsema);
+
+       spin_lock_irqsave(session->host->host_lock, flags);
+       spin_lock(&session->lock);
+       conn->stop_stage = flag;
+       conn->c_stage = ISCSI_CONN_STOPPED;
+       set_bit(SUSPEND_BIT, &conn->suspend_tx);
+
+       if (flag != STOP_CONN_SUSPEND)
+               session->conn_cnt--;
+
+       if (session->conn_cnt == 0 || session->leadconn == conn)
+               session->state = ISCSI_STATE_FAILED;
+
+       spin_unlock(&session->lock);
+       spin_unlock_irqrestore(session->host->host_lock, flags);
+
+       if (flag == STOP_CONN_TERM || flag == STOP_CONN_RECOVER) {
+               struct iscsi_cmd_task *ctask;
+               struct iscsi_mgmt_task *mtask;
+
+               /*
+                * Socket must go now.
+                */
+               sock_hold(conn->sock->sk);
+               iscsi_conn_restore_callbacks(conn);
+               sock_put(conn->sock->sk);
+
+               /*
+                * flush xmit queues.
+                */
+               spin_lock_bh(&session->lock);
+               while (__kfifo_get(conn->writequeue, (void*)&ctask,
+                           sizeof(void*)) ||
+                       __kfifo_get(conn->xmitqueue, (void*)&ctask,
+                           sizeof(void*))) {
+                       struct iscsi_r2t_info *r2t;
+
+                       /*
+                        * flush ctask's r2t queues
+                        */
+                       while (__kfifo_get(ctask->r2tqueue, (void*)&r2t,
+                               sizeof(void*)))
+                               __kfifo_put(ctask->r2tpool.queue, (void*)&r2t,
+                                           sizeof(void*));
+
+                       spin_unlock_bh(&session->lock);
+                       local_bh_disable();
+                       iscsi_ctask_cleanup(conn, ctask);
+                       local_bh_enable();
+                       spin_lock_bh(&session->lock);
+               }
+               conn->ctask = NULL;
+               while (__kfifo_get(conn->immqueue, (void*)&mtask,
+                          sizeof(void*)) ||
+                       __kfifo_get(conn->mgmtqueue, (void*)&mtask,
+                          sizeof(void*))) {
+                       __kfifo_put(session->mgmtpool.queue,
+                                   (void*)&mtask, sizeof(void*));
+               }
+               conn->mtask = NULL;
+               spin_unlock_bh(&session->lock);
+
+               /*
+                * release socket only after we stopped data_xmit()
+                * activity and flushed all outstandings
+                */
+               sock_release(conn->sock);
+               conn->sock = NULL;
+
+               /*
+                * 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->hdr_size = sizeof(struct iscsi_hdr);
+       }
+       up(&conn->xmitsema);
+}
+
+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 << CID_SHIFT) |
+                          (session->age << 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);
+
+       memcpy(&mtask->hdr, hdr, sizeof(struct iscsi_hdr));
+
+       if (conn->c_stage == ISCSI_CONN_INITIAL_STAGE ||
+           conn->stop_stage == STOP_CONN_RECOVER)
+               iscsi_buf_init_virt(&mtask->headbuf, (char*)&mtask->hdr,
+                                   sizeof(struct iscsi_hdr));
+       else
+               /* this will update header digest */
+               iscsi_buf_init_hdr(conn, &mtask->headbuf, (char*)&mtask->hdr,
+                                   (u8 *)mtask->hdrext);
+
+       spin_unlock_bh(&session->lock);
+
+       if (data_size) {
+               memcpy(mtask->data, data, data_size);
+               mtask->data_count = data_size;
+       } else
+               mtask->data_count = 0;
+
+       mtask->xmstate = XMSTATE_IMM_HDR;
+
+       if (mtask->data_count) {
+               iscsi_buf_init_iov(&mtask->sendbuf, (char*)mtask->data,
+                                   mtask->data_count);
+       }
+
+       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*));
+
+       schedule_work(&conn->xmitwork);
+
+       return 0;
+}
+
+static int
+iscsi_eh_host_reset(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;
+
+       spin_lock_bh(&session->lock);
+       if (session->state == ISCSI_STATE_TERMINATE) {
+               debug_scsi("failing host reset: session terminated "
+                          "[CID %d age %d]", conn->id, session->age);
+               spin_unlock_bh(&session->lock);
+               return FAILED;
+       }
+       spin_unlock_bh(&session->lock);
+
+       debug_scsi("failing connection CID %d due to SCSI host reset "
+                  "[itt 0x%x age %d]", conn->id, ctask->itt,
+                  session->age);
+       iscsi_conn_failure(conn, ISCSI_ERR_CONN_FAILED);
+
+       return SUCCESS;
+}
+
+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) {
+               __kfifo_put(session->mgmtpool.queue,
+                               (void*)&ctask->mtask, sizeof(void*));
+               conn->tmabort_state = TMABORT_TIMEDOUT;
+               debug_scsi("tmabort timedout [sc %lx itt 0x%x]\n",
+                       (long)ctask->sc, ctask->itt);
+               /* unblock eh_abort() */
+               wake_up(&conn->ehwait);
+       }
+       spin_unlock(&session->lock);
+}
+
+static int
+iscsi_eh_abort(struct scsi_cmnd *sc)
+{
+       int rc;
+       struct iscsi_cmd_task *ctask = (struct iscsi_cmd_task *)sc->SCp.ptr;
+       struct iscsi_conn *conn = ctask->conn;
+       struct iscsi_session *session = conn->session;
+
+       conn->eh_abort_cnt++;
+       debug_scsi("aborting [sc %lx itt 0x%x]\n", (long)sc, ctask->itt);
+
+       /*
+        * two cases for ERL=0 here:
+        *
+        * 1) connection-level failure;
+        * 2) recovery due protocol error;
+        */
+       down(&conn->xmitsema);
+       spin_lock_bh(&session->lock);
+       if (session->state != ISCSI_STATE_LOGGED_IN) {
+               if (session->state == ISCSI_STATE_TERMINATE) {
+                       spin_unlock_bh(&session->lock);
+                       up(&conn->xmitsema);
+                       goto failed;
+               }
+               spin_unlock_bh(&session->lock);
+       } else {
+               struct iscsi_tm *hdr = &conn->tmhdr;
+
+               /*
+                * Still LOGGED_IN...
+                */
+
+               if (!ctask->sc || sc->SCp.phase != session->age) {
+                       /*
+                        * 1) ctask completed before time out. But session
+                        *    is still ok => Happy Retry.
+                        * 2) session was re-open during time out of ctask.
+                        */
+                       spin_unlock_bh(&session->lock);
+                       up(&conn->xmitsema);
+                       goto success;
+               }
+               conn->tmabort_state = TMABORT_INITIAL;
+               spin_unlock_bh(&session->lock);
+
+               /*
+                * ctask timed out but session is OK
+                * ERL=0 requires task mgmt abort to be issued on each
+                * failed command. 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]", ctask->itt);
+               } else {
+                       struct iscsi_r2t_info *r2t;
+
+                       /*
+                        * TMF abort vs. TMF response race logic
+                        */
+                       spin_lock_bh(&session->lock);
+                       ctask->mtask = (struct iscsi_mgmt_task *)
+                               session->mgmt_cmds[(hdr->itt & ITT_MASK) -
+                                                       ISCSI_MGMT_ITT_OFFSET];
+                       /*
+                        * have to flush r2tqueue to avoid r2t leaks
+                        */
+                       while (__kfifo_get(ctask->r2tqueue, (void*)&r2t,
+                               sizeof(void*))) {
+                               __kfifo_put(ctask->r2tpool.queue, (void*)&r2t,
+                                       sizeof(void*));
+                       }
+                       if (conn->tmabort_state == TMABORT_INITIAL) {
+                               conn->tmfcmd_pdus_cnt++;
+                               conn->tmabort_timer.expires = 3*HZ + jiffies;
+                               conn->tmabort_timer.function =
+                                               iscsi_tmabort_timedout;
+                               conn->tmabort_timer.data = (unsigned long)ctask;
+                               add_timer(&conn->tmabort_timer);
+                               debug_scsi("abort sent [itt 0x%x]", ctask->itt);
+                       } else {
+                               if (!ctask->sc ||
+                                   conn->tmabort_state == TMABORT_SUCCESS) {
+                                       conn->tmabort_state = TMABORT_INITIAL;
+                                       spin_unlock_bh(&session->lock);
+                                       up(&conn->xmitsema);
+                                       goto success;
+                               }
+                               conn->tmabort_state = TMABORT_INITIAL;
+                               iscsi_conn_failure(conn, ISCSI_ERR_CONN_FAILED);
+                       }
+                       spin_unlock_bh(&session->lock);
+               }
+       }
+       up(&conn->xmitsema);
+
+
+       /*
+        * block eh thread until:
+        *
+        * 1) abort response;
+        * 2) abort timeout;
+        * 3) session re-opened;
+        * 4) session terminated;
+        */
+       for (;;) {
+               int p_state = session->state;
+
+               rc = wait_event_interruptible(conn->ehwait,
+                       (p_state == ISCSI_STATE_LOGGED_IN ?
+                        (session->state == ISCSI_STATE_TERMINATE ||
+                         conn->tmabort_state != TMABORT_INITIAL) :
+                        (session->state == ISCSI_STATE_TERMINATE ||
+                         session->state == ISCSI_STATE_LOGGED_IN)));
+               if (rc) {
+                       /* shutdown.. */
+                       session->state = ISCSI_STATE_TERMINATE;
+                       goto failed;
+               }
+
+               if (signal_pending(current))
+                       flush_signals(current);
+
+               if (session->state == ISCSI_STATE_TERMINATE)
+                       goto failed;
+
+               spin_lock_bh(&session->lock);
+               if (sc->SCp.phase == session->age &&
+                  (conn->tmabort_state == TMABORT_TIMEDOUT ||
+                   conn->tmabort_state == TMABORT_FAILED)) {
+                       conn->tmabort_state = TMABORT_INITIAL;
+                       if (!ctask->sc) {
+                               /*
+                                * ctask completed before tmf abort response or
+                                * time out.
+                                * But session is still ok => Happy Retry.
+                                */
+                               spin_unlock_bh(&session->lock);
+                               break;
+                       }
+                       spin_unlock_bh(&session->lock);
+                       iscsi_conn_failure(conn, ISCSI_ERR_CONN_FAILED);
+                       continue;
+               }
+               spin_unlock_bh(&session->lock);
+               break;
+       }
+
+success:
+       debug_scsi("abort success [sc %lx itt 0x%x]\n", (long)sc, ctask->itt);
+       rc = SUCCESS;
+       goto exit;
+
+failed:
+       debug_scsi("abort failed [sc %lx itt 0x%x]\n", (long)sc, ctask->itt);
+       rc = FAILED;
+
+exit:
+       del_timer_sync(&conn->tmabort_timer);
+
+       down(&conn->xmitsema);
+       if (conn->sock) {
+               struct sock *sk = conn->sock->sk;
+
+               write_lock_bh(&sk->sk_callback_lock);
+               iscsi_ctask_cleanup(conn, ctask);
+               write_unlock_bh(&sk->sk_callback_lock);
+       }
+       up(&conn->xmitsema);
+       return rc;
+}
+
+static int
+iscsi_r2tpool_alloc(struct iscsi_session *session)
+{
+       int i;
+       int cmd_i;
+
+       /*
+        * initialize per-task: R2T pool and xmit queue
+        */
+       for (cmd_i = 0; cmd_i < session->cmds_max; cmd_i++) {
+               struct iscsi_cmd_task *ctask = session->cmds[cmd_i];
+
+               /*
+                * pre-allocated x4 as much r2ts to handle race when
+                * target acks DataOut faster than we data_xmit() queues
+                * could replenish r2tqueue.
+                */
+
+               /* R2T pool */
+               if (iscsi_pool_init(&ctask->r2tpool, session->max_r2t * 4,
+                       (void***)&ctask->r2ts, sizeof(struct iscsi_r2t_info))) {
+                       goto r2t_alloc_fail;
+               }
+
+               /* R2T xmit queue */
+               ctask->r2tqueue = kfifo_alloc(
+                     session->max_r2t * 4 * sizeof(void*), GFP_KERNEL, NULL);
+               if (ctask->r2tqueue == ERR_PTR(-ENOMEM)) {
+                       iscsi_pool_free(&ctask->r2tpool, (void**)ctask->r2ts);
+                       goto r2t_alloc_fail;
+               }
+
+               /*
+                * number of
+                * Data-Out PDU's within R2T-sequence can be quite big;
+                * using mempool
+                */
+               ctask->datapool = mempool_create(ISCSI_DTASK_DEFAULT_MAX,
+                        mempool_alloc_slab, mempool_free_slab, taskcache);
+               if (ctask->datapool == NULL) {
+                       kfifo_free(ctask->r2tqueue);
+                       iscsi_pool_free(&ctask->r2tpool, (void**)ctask->r2ts);
+                       goto r2t_alloc_fail;
+               }
+               INIT_LIST_HEAD(&ctask->dataqueue);
+       }
+
+       return 0;
+
+r2t_alloc_fail:
+       for (i = 0; i < cmd_i; i++) {
+               mempool_destroy(session->cmds[i]->datapool);
+               kfifo_free(session->cmds[i]->r2tqueue);
+               iscsi_pool_free(&session->cmds[i]->r2tpool,
+                               (void**)session->cmds[i]->r2ts);
+       }
+       return -ENOMEM;
+}
+
+static void
+iscsi_r2tpool_free(struct iscsi_session *session)
+{
+       int i;
+
+       for (i = 0; i < session->cmds_max; i++) {
+               mempool_destroy(session->cmds[i]->datapool);
+               kfifo_free(session->cmds[i]->r2tqueue);
+               iscsi_pool_free(&session->cmds[i]->r2tpool,
+                               (void**)session->cmds[i]->r2ts);
+       }
+}
+
+static struct scsi_host_template iscsi_sht = {
+       .name                   = "iSCSI Initiator over TCP/IP, v."
+                                 ISCSI_VERSION_STR,
+        .queuecommand           = iscsi_queuecommand,
+       .can_queue              = ISCSI_XMIT_CMDS_MAX - 1,
+       .sg_tablesize           = ISCSI_SG_TABLESIZE,
+       .cmd_per_lun            = ISCSI_CMD_PER_LUN,
+        .eh_abort_handler       = iscsi_eh_abort,
+        .eh_host_reset_handler = iscsi_eh_host_reset,
+        .use_clustering         = DISABLE_CLUSTERING,
+       .proc_name              = "iscsi_tcp",
+       .this_id                = -1,
+};
+
+static iscsi_sessionh_t
+iscsi_session_create(uint32_t initial_cmdsn, struct Scsi_Host *host)
+{
+       int cmd_i;
+       struct iscsi_session *session;
+
+       session = iscsi_hostdata(host->hostdata);
+       memset(session, 0, sizeof(struct iscsi_session));
+
+       session->host = host;
+       session->id = host->host_no;
+       session->state = ISCSI_STATE_LOGGED_IN;
+       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;
+
+       /* initialize SCSI PDU commands pool */
+       if (iscsi_pool_init(&session->cmdpool, session->cmds_max,
+               (void***)&session->cmds, 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++)
+               session->cmds[cmd_i]->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, 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++) {
+               session->mgmt_cmds[cmd_i]->itt = ISCSI_MGMT_ITT_OFFSET + cmd_i;
+               session->mgmt_cmds[cmd_i]->data = kmalloc(
+                       DEFAULT_MAX_RECV_DATA_SEGMENT_LENGTH, GFP_KERNEL);
+               if (!session->mgmt_cmds[cmd_i]->data) {
+                       int j;
+
+                       for (j = 0; j < cmd_i; j++)
+                               kfree(session->mgmt_cmds[j]->data);
+                       goto immdata_alloc_fail;
+               }
+       }
+
+       if (iscsi_r2tpool_alloc(session))
+               goto r2tpool_alloc_fail;
+
+       return iscsi_handle(session);
+
+r2tpool_alloc_fail:
+       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);
+immdata_alloc_fail:
+mgmtpool_alloc_fail:
+       iscsi_pool_free(&session->cmdpool, (void**)session->cmds);
+cmdpool_alloc_fail:
+       return iscsi_handle(NULL);
+}
+
+static void
+iscsi_session_destroy(iscsi_sessionh_t sessionh)
+{
+       int cmd_i;
+       struct iscsi_data_task *dtask, *n;
+       struct iscsi_session *session = iscsi_ptr(sessionh);
+
+       for (cmd_i = 0; cmd_i < session->cmds_max; cmd_i++) {
+               struct iscsi_cmd_task *ctask = session->cmds[cmd_i];
+               list_for_each_entry_safe(dtask, n, &ctask->dataqueue, item) {
+                       list_del(&dtask->item);
+                       mempool_free(dtask, ctask->datapool);
+               }
+       }
+
+       for (cmd_i = 0; cmd_i < session->mgmtpool_max; cmd_i++)
+               kfree(session->mgmt_cmds[cmd_i]->data);
+
+       iscsi_r2tpool_free(session);
+       iscsi_pool_free(&session->mgmtpool, (void**)session->mgmt_cmds);
+       iscsi_pool_free(&session->cmdpool, (void**)session->cmds);
+}
+
+static int
+iscsi_conn_set_param(iscsi_connh_t connh, enum iscsi_param param,
+                    uint32_t value)
+{
+       struct iscsi_conn *conn = iscsi_ptr(connh);
+       struct iscsi_session *session = conn->session;
+
+       spin_lock_bh(&session->lock);
+       if (conn->c_stage != ISCSI_CONN_INITIAL_STAGE &&
+           conn->stop_stage != STOP_CONN_RECOVER) {
+               printk(KERN_ERR "iscsi_tcp: can not change parameter [%d]\n",
+                      param);
+               spin_unlock_bh(&session->lock);
+               return 0;
+       }
+       spin_unlock_bh(&session->lock);
+
+       switch(param) {
+       case ISCSI_PARAM_MAX_RECV_DLENGTH: {
+               char *saveptr = conn->data;
+               int flags = GFP_KERNEL;
+
+               if (conn->data_size >= value) {
+                       conn->max_recv_dlength = value;
+                       break;
+               }
+
+               spin_lock_bh(&session->lock);
+               if (conn->stop_stage == STOP_CONN_RECOVER)
+                       flags = GFP_ATOMIC;
+               spin_unlock_bh(&session->lock);
+
+               if (value <= PAGE_SIZE)
+                       conn->data = kmalloc(value, flags);
+               else
+                       conn->data = (void*)__get_free_pages(flags,
+                                                            get_order(value));
+               if (conn->data == NULL) {
+                       conn->data = saveptr;
+                       return -ENOMEM;
+               }
+               if (conn->data_size <= PAGE_SIZE)
+                       kfree(saveptr);
+               else
+                       free_pages((unsigned long)saveptr,
+                                  get_order(conn->data_size));
+               conn->max_recv_dlength = value;
+               conn->data_size = value;
+               }
+               break;
+       case ISCSI_PARAM_MAX_XMIT_DLENGTH:
+               conn->max_xmit_dlength =  value;
+               break;
+       case ISCSI_PARAM_HDRDGST_EN:
+               conn->hdrdgst_en = value;
+               conn->hdr_size = sizeof(struct iscsi_hdr);
+               if (conn->hdrdgst_en) {
+                       conn->hdr_size += sizeof(__u32);
+                       if (!conn->tx_tfm)
+                               conn->tx_tfm = crypto_alloc_tfm("crc32c", 0);
+                       if (!conn->tx_tfm)
+                               return -ENOMEM;
+                       if (!conn->rx_tfm)
+                               conn->rx_tfm = crypto_alloc_tfm("crc32c", 0);
+                       if (!conn->rx_tfm) {
+                               crypto_free_tfm(conn->tx_tfm);
+                               return -ENOMEM;
+                       }
+               } else {
+                       if (conn->tx_tfm)
+                               crypto_free_tfm(conn->tx_tfm);
+                       if (conn->rx_tfm)
+                               crypto_free_tfm(conn->rx_tfm);
+               }
+               break;
+       case ISCSI_PARAM_DATADGST_EN:
+               conn->datadgst_en = value;
+               if (conn->datadgst_en) {
+                       if (!conn->data_tx_tfm)
+                               conn->data_tx_tfm =
+                                   crypto_alloc_tfm("crc32c", 0);
+                       if (!conn->data_tx_tfm)
+                               return -ENOMEM;
+                       if (!conn->data_rx_tfm)
+                               conn->data_rx_tfm =
+                                   crypto_alloc_tfm("crc32c", 0);
+                       if (!conn->data_rx_tfm) {
+                               crypto_free_tfm(conn->data_tx_tfm);
+                               return -ENOMEM;
+                       }
+               } else {
+                       if (conn->data_tx_tfm)
+                               crypto_free_tfm(conn->data_tx_tfm);
+                       if (conn->data_rx_tfm)
+                               crypto_free_tfm(conn->data_rx_tfm);
+               }
+               break;
+       case ISCSI_PARAM_INITIAL_R2T_EN:
+               session->initial_r2t_en = value;
+               break;
+       case ISCSI_PARAM_MAX_R2T:
+               if (session->max_r2t == roundup_pow_of_two(value))
+                       break;
+               iscsi_r2tpool_free(session);
+               session->max_r2t = value;
+               if (session->max_r2t & (session->max_r2t - 1))
+                       session->max_r2t = roundup_pow_of_two(session->max_r2t);
+               if (iscsi_r2tpool_alloc(session))
+                       return -ENOMEM;
+               break;
+       case ISCSI_PARAM_IMM_DATA_EN:
+               session->imm_data_en = value;
+               break;
+       case ISCSI_PARAM_FIRST_BURST:
+               session->first_burst = value;
+               break;
+       case ISCSI_PARAM_MAX_BURST:
+               session->max_burst = value;
+               break;
+       case ISCSI_PARAM_PDU_INORDER_EN:
+               session->pdu_inorder_en = value;
+               break;
+       case ISCSI_PARAM_DATASEQ_INORDER_EN:
+               session->dataseq_inorder_en = value;
+               break;
+       case ISCSI_PARAM_ERL:
+               session->erl = value;
+               break;
+       case ISCSI_PARAM_IFMARKER_EN:
+               BUG_ON(value);
+               session->ifmarker_en = value;
+               break;
+       case ISCSI_PARAM_OFMARKER_EN:
+               BUG_ON(value);
+               session->ofmarker_en = value;
+               break;
+       default:
+               break;
+       }
+
+       return 0;
+}
+
+static int
+iscsi_conn_get_param(iscsi_connh_t connh, enum iscsi_param param,
+                    uint32_t *value)
+{
+       struct iscsi_conn *conn = iscsi_ptr(connh);
+       struct iscsi_session *session = conn->session;
+
+       switch(param) {
+       case ISCSI_PARAM_MAX_RECV_DLENGTH:
+               *value = conn->max_recv_dlength;
+               break;
+       case ISCSI_PARAM_MAX_XMIT_DLENGTH:
+               *value = conn->max_xmit_dlength;
+               break;
+       case ISCSI_PARAM_HDRDGST_EN:
+               *value = conn->hdrdgst_en;
+               break;
+       case ISCSI_PARAM_DATADGST_EN:
+               *value = conn->datadgst_en;
+               break;
+       case ISCSI_PARAM_INITIAL_R2T_EN:
+               *value = session->initial_r2t_en;
+               break;
+       case ISCSI_PARAM_MAX_R2T:
+               *value = session->max_r2t;
+               break;
+       case ISCSI_PARAM_IMM_DATA_EN:
+               *value = session->imm_data_en;
+               break;
+       case ISCSI_PARAM_FIRST_BURST:
+               *value = session->first_burst;
+               break;
+       case ISCSI_PARAM_MAX_BURST:
+               *value = session->max_burst;
+               break;
+       case ISCSI_PARAM_PDU_INORDER_EN:
+               *value = session->pdu_inorder_en;
+               break;
+       case ISCSI_PARAM_DATASEQ_INORDER_EN:
+               *value = session->dataseq_inorder_en;
+               break;
+       case ISCSI_PARAM_ERL:
+               *value = session->erl;
+               break;
+       case ISCSI_PARAM_IFMARKER_EN:
+               *value = session->ifmarker_en;
+               break;
+       case ISCSI_PARAM_OFMARKER_EN:
+               *value = session->ofmarker_en;
+               break;
+       default:
+               return ISCSI_ERR_PARAM_NOT_FOUND;
+       }
+
+       return 0;
+}
+
+static void
+iscsi_conn_get_stats(iscsi_connh_t connh, struct iscsi_stats *stats)
+{
+       struct iscsi_conn *conn = iscsi_ptr(connh);
+
+       stats->txdata_octets = conn->txdata_octets;
+       stats->rxdata_octets = conn->rxdata_octets;
+       stats->scsicmd_pdus = conn->scsicmd_pdus_cnt;
+       stats->dataout_pdus = conn->dataout_pdus_cnt;
+       stats->scsirsp_pdus = conn->scsirsp_pdus_cnt;
+       stats->datain_pdus = conn->datain_pdus_cnt;
+       stats->r2t_pdus = conn->r2t_pdus_cnt;
+       stats->tmfcmd_pdus = conn->tmfcmd_pdus_cnt;
+       stats->tmfrsp_pdus = conn->tmfrsp_pdus_cnt;
+       stats->custom_length = 3;
+       strcpy(stats->custom[0].desc, "tx_sendpage_failures");
+       stats->custom[0].value = conn->sendpage_failures_cnt;
+       strcpy(stats->custom[1].desc, "rx_discontiguous_hdr");
+       stats->custom[1].value = conn->discontiguous_hdr_cnt;
+       strcpy(stats->custom[2].desc, "eh_abort_cnt");
+       stats->custom[2].value = conn->eh_abort_cnt;
+}
+
+static int
+iscsi_conn_send_pdu(iscsi_connh_t connh, struct iscsi_hdr *hdr, char *data,
+                   uint32_t data_size)
+{
+       struct iscsi_conn *conn = iscsi_ptr(connh);
+       int rc;
+
+       down(&conn->xmitsema);
+       rc = iscsi_conn_send_generic(conn, hdr, data, data_size);
+       up(&conn->xmitsema);
+
+       return rc;
+}
+
+static struct iscsi_transport iscsi_tcp_transport = {
+       .owner                  = THIS_MODULE,
+       .name                   = "tcp",
+       .caps                   = CAP_RECOVERY_L0 | CAP_MULTI_R2T | CAP_HDRDGST
+                                 | CAP_DATADGST,
+       .host_template          = &iscsi_sht,
+       .hostdata_size          = sizeof(struct iscsi_session),
+       .max_conn               = 1,
+       .max_cmd_len            = ISCSI_TCP_MAX_CMD_LEN,
+       .create_session         = iscsi_session_create,
+       .destroy_session        = iscsi_session_destroy,
+       .create_conn            = iscsi_conn_create,
+       .bind_conn              = iscsi_conn_bind,
+       .destroy_conn           = iscsi_conn_destroy,
+       .set_param              = iscsi_conn_set_param,
+       .get_param              = iscsi_conn_get_param,
+       .start_conn             = iscsi_conn_start,
+       .stop_conn              = iscsi_conn_stop,
+       .send_pdu               = iscsi_conn_send_pdu,
+       .get_stats              = iscsi_conn_get_stats,
+};
+
+static int __init
+iscsi_tcp_init(void)
+{
+       int error;
+
+       if (iscsi_max_lun < 1) {
+               printk(KERN_ERR "Invalid max_lun value of %u\n", iscsi_max_lun);
+               return -EINVAL;
+       }
+       iscsi_tcp_transport.max_lun = iscsi_max_lun;
+
+       taskcache = kmem_cache_create("iscsi_taskcache",
+                       sizeof(struct iscsi_data_task), 0,
+                       SLAB_HWCACHE_ALIGN | SLAB_NO_REAP, NULL, NULL);
+       if (!taskcache)
+               return -ENOMEM;
+
+       error = iscsi_register_transport(&iscsi_tcp_transport);
+       if (error)
+               kmem_cache_destroy(taskcache);
+
+       return error;
+}
+
+static void __exit
+iscsi_tcp_exit(void)
+{
+       iscsi_unregister_transport(&iscsi_tcp_transport);
+       kmem_cache_destroy(taskcache);
+}
+
+module_init(iscsi_tcp_init);
+module_exit(iscsi_tcp_exit);