iscsi_tcp.c 93.1 KB
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/*
 * 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");
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MODULE_VERSION("0:4.409");
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/* #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
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iscsi_hdr_digest(struct iscsi_conn *conn, struct iscsi_buf *buf,
		 u8* crc)
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{
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	crypto_digest_digest(conn->tx_tfm, &buf->sg, 1, crc);
	buf->sg.length += sizeof(uint32_t);
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}

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;

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	iscsi_buf_init_virt(&r2t->headbuf, (char*)hdr,
			   sizeof(struct iscsi_hdr));
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	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 */
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	conn->in.ahslen = hdr->hlength * 4;
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	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 */
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	conn->in.opcode = hdr->opcode & ISCSI_OPCODE_MASK;
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	/* 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;
		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:
693
		case ISCSI_OP_LOGOUT_RSP: 
694 695 696 697 698 699 700 701 702 703 704 705 706 707 708 709 710 711 712 713 714 715 716 717 718 719 720 721 722 723 724 725 726
			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)->
727
					response == ISCSI_TMF_RSP_COMPLETE ?
728 729 730 731 732 733
						TMABORT_SUCCESS:TMABORT_FAILED;
				/* unblock eh_abort() */
				wake_up(&conn->ehwait);
			}
			spin_unlock(&session->lock);
			break;
734 735 736 737 738 739 740 741 742 743 744 745 746 747 748 749 750 751 752 753 754 755 756 757 758 759 760
		case ISCSI_OP_NOOP_IN: 
			if (hdr->ttt != ISCSI_RESERVED_TAG) {
				rc = ISCSI_ERR_PROTO;
				break;
			}
			rc = iscsi_check_assign_cmdsn(session, 
						(struct iscsi_nopin*)hdr);
			if (rc)
				break;
			conn->exp_statsn = be32_to_cpu(hdr->statsn) + 1;

			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;
761 762 763 764 765
		default:
			rc = ISCSI_ERR_BAD_OPCODE;
			break;
		}
	} else if (conn->in.itt == ISCSI_RESERVED_TAG) {
766 767 768 769
		switch(conn->in.opcode) {
		case ISCSI_OP_NOOP_IN:
			if (!conn->in.datalen) {
				rc = iscsi_check_assign_cmdsn(session,
770
						 (struct iscsi_nopin*)hdr);
771 772 773 774 775 776 777 778 779 780
				if (!rc && hdr->ttt != ISCSI_RESERVED_TAG)
					rc = iscsi_recv_pdu(iscsi_handle(conn),
							    hdr, NULL, 0);
			} else 
				rc = ISCSI_ERR_PROTO;
			break;
		case ISCSI_OP_REJECT:
			/* we need sth like iscsi_reject_rsp()*/
		case ISCSI_OP_ASYNC_EVENT:
			/* we need sth like iscsi_async_event_rsp() */
781
			rc = ISCSI_ERR_BAD_OPCODE;
782 783 784 785 786
			break;
		default:
			rc = ISCSI_ERR_BAD_OPCODE;
			break;
		}
787 788 789 790 791 792 793 794 795 796 797 798 799 800 801 802 803 804 805 806 807 808 809 810 811 812 813 814 815 816 817 818 819 820 821 822 823 824 825 826 827 828 829 830 831 832 833 834 835 836 837 838 839 840 841 842 843 844 845 846 847 848 849 850 851 852 853 854 855 856 857 858 859 860 861 862 863 864 865 866 867 868 869 870 871 872 873 874 875 876 877 878 879 880 881 882 883 884 885 886 887 888 889 890 891 892 893 894 895 896 897 898 899 900 901 902 903 904 905 906 907 908 909 910 911 912 913 914 915 916 917 918 919 920 921 922 923 924 925 926 927 928 929 930 931 932 933 934 935 936 937 938 939 940 941 942 943 944 945 946 947 948 949 950 951 952 953 954 955 956 957 958 959 960 961 962 963 964 965 966 967 968 969 970 971 972 973 974 975 976 977 978 979 980 981 982 983 984 985 986 987 988 989 990 991 992 993 994 995 996 997 998 999 1000 1001 1002 1003 1004 1005 1006 1007 1008 1009 1010 1011 1012 1013 1014 1015 1016 1017 1018 1019 1020 1021 1022 1023 1024 1025 1026 1027 1028 1029 1030 1031 1032 1033 1034 1035 1036 1037 1038 1039 1040 1041 1042 1043 1044 1045 1046 1047 1048 1049 1050 1051 1052 1053 1054 1055 1056 1057 1058 1059 1060 1061 1062 1063 1064 1065 1066 1067 1068 1069 1070 1071 1072 1073 1074 1075 1076 1077 1078 1079 1080 1081 1082 1083
	} 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 processed;
	char pad[ISCSI_PAD_LEN];
	struct scatterlist sg;

	/*
	 * Save current SKB and its offset in the corresponding
	 * connection context.
	 */
1084
	conn->in.copy = skb->len - offset;
1085 1086 1087 1088 1089 1090 1091 1092 1093 1094 1095 1096 1097 1098 1099 1100 1101 1102 1103 1104 1105 1106 1107 1108 1109 1110 1111 1112 1113 1114 1115 1116 1117 1118 1119 1120 1121 1122 1123 1124 1125 1126 1127 1128 1129 1130 1131 1132 1133 1134 1135 1136 1137 1138 1139 1140 1141 1142 1143 1144 1145 1146 1147 1148 1149 1150 1151 1152 1153 1154 1155 1156 1157 1158 1159 1160 1161 1162 1163 1164 1165 1166 1167 1168 1169 1170 1171 1172 1173 1174 1175 1176 1177 1178 1179 1180 1181 1182 1183 1184 1185 1186 1187 1188 1189 1190 1191 1192 1193 1194 1195 1196 1197 1198 1199 1200 1201 1202 1203 1204 1205 1206 1207 1208 1209 1210 1211 1212 1213 1214 1215 1216 1217 1218 1219 1220 1221 1222 1223 1224 1225 1226 1227 1228 1229 1230 1231 1232 1233 1234 1235 1236 1237 1238 1239
	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;

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	if ((sk->sk_state == TCP_CLOSE_WAIT ||
	     sk->sk_state == TCP_CLOSE) &&
	    !atomic_read(&sk->sk_rmem_alloc)) {
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		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;
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	if (buf->sent + size != buf->sg.length || *count != size)
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		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++;

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	iscsi_buf_init_virt(&r2t->headbuf, (char*)hdr,
			   sizeof(struct iscsi_hdr));
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	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;
	}

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	iscsi_buf_init_virt(&ctask->headbuf, (char*)hdr,
			   sizeof(struct iscsi_hdr));
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	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);
	}

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	iscsi_buf_init_virt(&ctask->headbuf, (char*)&ctask->hdr, 
			    sizeof(struct iscsi_hdr));
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	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;
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		if (conn->c_stage != ISCSI_CONN_INITIAL_STAGE &&
	    	    conn->stop_stage != STOP_CONN_RECOVER &&
		    conn->hdrdgst_en)
			iscsi_hdr_digest(conn, &mtask->headbuf,
					(u8*)mtask->hdrext);
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		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;
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	if (conn->hdrdgst_en) 
		iscsi_hdr_digest(conn, &ctask->headbuf, (u8*)ctask->hdrext);
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	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;
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	if (conn->hdrdgst_en) 
		iscsi_hdr_digest(conn, &ctask->headbuf, (u8*)ctask->hdrext);
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	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;
1834 1835 1836
		if (conn->hdrdgst_en)
			iscsi_hdr_digest(conn, &ctask->headbuf,
					(u8*)dtask->hdrext);
1837 1838 1839 1840 1841 1842 1843 1844 1845 1846 1847 1848 1849 1850 1851 1852 1853 1854 1855 1856 1857 1858 1859 1860 1861 1862 1863 1864 1865 1866 1867 1868 1869 1870 1871 1872 1873 1874 1875 1876 1877 1878 1879 1880 1881 1882 1883 1884 1885 1886 1887 1888 1889 1890 1891 1892 1893 1894 1895 1896 1897 1898 1899 1900 1901 1902 1903 1904 1905 1906 1907 1908 1909 1910 1911 1912 1913 1914 1915 1916 1917 1918 1919 1920 1921 1922 1923 1924 1925 1926 1927 1928 1929 1930 1931 1932 1933 1934 1935 1936 1937 1938 1939 1940 1941 1942 1943 1944 1945 1946 1947 1948 1949 1950 1951 1952 1953 1954 1955 1956 1957 1958 1959 1960 1961 1962 1963 1964 1965 1966 1967 1968 1969 1970 1971 1972 1973 1974 1975 1976 1977 1978 1979 1980 1981 1982 1983 1984 1985 1986 1987 1988 1989 1990 1991 1992 1993 1994 1995 1996 1997 1998 1999 2000 2001 2002 2003 2004 2005 2006 2007 2008 2009 2010 2011 2012 2013 2014 2015 2016 2017 2018 2019 2020 2021 2022 2023 2024 2025 2026 2027 2028 2029 2030 2031 2032 2033 2034 2035 2036 2037 2038 2039 2040 2041 2042 2043 2044 2045 2046 2047 2048 2049 2050 2051 2052 2053 2054 2055 2056 2057 2058 2059 2060 2061 2062 2063 2064 2065 2066 2067 2068 2069 2070 2071 2072 2073 2074 2075 2076 2077 2078 2079 2080 2081 2082 2083 2084 2085 2086 2087 2088 2089 2090 2091 2092 2093 2094 2095 2096 2097 2098 2099 2100 2101 2102 2103 2104 2105 2106 2107 2108 2109 2110 2111 2112 2113 2114 2115 2116 2117 2118 2119 2120 2121 2122 2123 2124 2125 2126 2127 2128 2129 2130 2131 2132 2133 2134 2135 2136 2137 2138 2139 2140
		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;
2141 2142 2143
		if (conn->hdrdgst_en)
			iscsi_hdr_digest(conn, &r2t->headbuf, 
					(u8*)r2t->dtask->hdrext);
2144 2145 2146 2147 2148 2149 2150 2151 2152 2153 2154 2155 2156 2157 2158 2159 2160 2161 2162 2163 2164 2165 2166 2167 2168 2169 2170 2171 2172 2173 2174 2175 2176 2177 2178 2179 2180 2181 2182 2183 2184 2185 2186 2187 2188 2189 2190 2191 2192 2193 2194 2195 2196 2197 2198 2199 2200 2201 2202 2203 2204 2205 2206 2207 2208 2209 2210 2211 2212 2213 2214 2215 2216 2217 2218 2219 2220 2221 2222 2223 2224 2225 2226 2227 2228 2229 2230 2231 2232 2233 2234 2235 2236 2237 2238 2239 2240 2241 2242 2243 2244 2245 2246 2247 2248 2249 2250 2251 2252 2253 2254 2255 2256 2257 2258 2259 2260 2261 2262 2263 2264 2265 2266 2267 2268 2269 2270 2271 2272 2273 2274 2275 2276 2277 2278 2279 2280 2281 2282 2283 2284 2285 2286 2287 2288 2289 2290 2291 2292 2293 2294 2295 2296 2297 2298 2299 2300 2301 2302 2303 2304 2305 2306 2307 2308 2309 2310 2311 2312 2313 2314 2315 2316 2317 2318 2319 2320 2321 2322 2323 2324 2325 2326 2327 2328 2329 2330 2331 2332 2333 2334 2335 2336 2337 2338 2339 2340 2341 2342 2343 2344 2345 2346 2347 2348 2349 2350 2351 2352 2353 2354 2355 2356 2357 2358 2359 2360 2361 2362 2363 2364 2365 2366 2367 2368 2369 2370 2371 2372 2373 2374 2375 2376 2377 2378 2379 2380 2381 2382 2383 2384 2385 2386 2387 2388 2389 2390 2391 2392 2393 2394 2395 2396 2397 2398 2399 2400 2401 2402 2403 2404 2405 2406 2407 2408 2409 2410 2411 2412 2413 2414 2415 2416 2417 2418 2419 2420 2421 2422 2423 2424 2425 2426 2427 2428 2429 2430 2431 2432 2433 2434 2435 2436 2437 2438 2439 2440 2441 2442 2443 2444 2445 2446 2447 2448 2449 2450 2451 2452 2453 2454 2455 2456 2457 2458 2459 2460 2461 2462 2463 2464 2465 2466 2467 2468 2469 2470 2471 2472 2473 2474 2475 2476 2477 2478 2479 2480 2481 2482 2483 2484 2485 2486 2487 2488 2489 2490 2491 2492 2493 2494 2495 2496 2497 2498 2499 2500 2501 2502 2503 2504 2505 2506 2507 2508 2509 2510 2511 2512 2513 2514 2515 2516 2517 2518 2519 2520 2521 2522 2523 2524 2525 2526 2527 2528 2529 2530 2531 2532 2533 2534 2535 2536 2537 2538 2539 2540 2541 2542 2543 2544 2545 2546 2547 2548 2549 2550 2551 2552 2553 2554 2555 2556 2557 2558 2559 2560 2561 2562 2563 2564 2565 2566 2567 2568 2569 2570 2571 2572 2573 2574 2575 2576 2577 2578 2579 2580 2581 2582 2583 2584 2585 2586 2587 2588 2589 2590 2591 2592 2593 2594 2595 2596 2597 2598 2599 2600 2601 2602 2603 2604 2605 2606 2607 2608 2609 2610 2611 2612 2613 2614 2615 2616 2617 2618 2619 2620 2621 2622 2623 2624 2625 2626 2627 2628 2629 2630 2631 2632 2633 2634 2635 2636 2637 2638 2639 2640 2641 2642 2643 2644 2645 2646 2647 2648 2649 2650 2651 2652 2653 2654 2655 2656 2657 2658 2659 2660 2661 2662 2663 2664 2665 2666 2667 2668 2669 2670 2671 2672 2673 2674 2675 2676 2677 2678 2679 2680 2681 2682 2683 2684 2685 2686 2687 2688 2689 2690 2691 2692 2693 2694 2695 2696 2697 2698 2699 2700 2701 2702 2703 2704 2705 2706 2707 2708 2709 2710 2711 2712 2713 2714 2715 2716 2717 2718 2719 2720 2721 2722 2723 2724 2725 2726 2727 2728 2729 2730 2731 2732 2733 2734 2735 2736 2737 2738 2739 2740 2741 2742 2743 2744 2745 2746 2747 2748 2749 2750 2751 2752 2753 2754 2755 2756 2757 2758 2759 2760 2761 2762 2763 2764 2765 2766 2767 2768 2769 2770 2771 2772 2773 2774 2775 2776 2777 2778 2779 2780 2781 2782 2783 2784 2785 2786 2787 2788 2789 2790 2791 2792 2793 2794 2795 2796 2797 2798 2799 2800 2801 2802 2803 2804 2805 2806 2807 2808 2809 2810 2811 2812 2813 2814 2815 2816 2817 2818 2819 2820 2821 2822 2823 2824 2825 2826 2827 2828 2829 2830 2831 2832 2833 2834 2835 2836 2837 2838 2839 2840 2841 2842 2843 2844 2845 2846 2847 2848 2849 2850 2851 2852 2853 2854 2855 2856 2857 2858 2859 2860 2861 2862 2863 2864 2865 2866 2867 2868 2869 2870 2871 2872 2873 2874 2875 2876 2877 2878 2879 2880 2881 2882 2883 2884 2885 2886 2887 2888 2889 2890 2891 2892 2893 2894 2895 2896 2897 2898 2899 2900 2901 2902 2903 2904 2905 2906 2907 2908 2909 2910 2911 2912 2913
		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));

2914
	iscsi_buf_init_virt(&mtask->headbuf, (char*)&mtask->hdr,
2915 2916 2917 2918 2919 2920 2921 2922 2923 2924 2925 2926 2927 2928 2929 2930 2931 2932 2933 2934 2935 2936 2937 2938 2939 2940 2941 2942 2943 2944 2945 2946 2947 2948 2949 2950 2951 2952 2953 2954 2955 2956 2957 2958 2959 2960 2961 2962 2963 2964 2965 2966 2967 2968 2969 2970 2971 2972 2973 2974 2975 2976 2977 2978 2979 2980 2981 2982 2983 2984 2985 2986 2987 2988 2989 2990 2991 2992 2993 2994 2995 2996 2997 2998 2999 3000 3001 3002 3003 3004 3005 3006 3007 3008 3009 3010 3011 3012 3013 3014 3015 3016 3017 3018 3019 3020 3021 3022 3023 3024 3025 3026 3027 3028 3029 3030 3031 3032 3033 3034 3035 3036 3037 3038 3039 3040 3041 3042 3043 3044 3045 3046 3047 3048 3049 3050 3051 3052 3053 3054 3055 3056 3057 3058 3059 3060 3061 3062 3063 3064 3065 3066 3067 3068 3069 3070 3071 3072 3073 3074 3075 3076 3077 3078 3079 3080 3081 3082 3083 3084 3085 3086 3087 3088 3089 3090 3091 3092 3093 3094 3095 3096 3097 3098 3099 3100 3101 3102 3103 3104 3105 3106 3107 3108 3109 3110 3111 3112 3113 3114 3115 3116 3117 3118 3119 3120 3121 3122 3123 3124 3125 3126 3127 3128 3129 3130 3131 3132 3133 3134 3135 3136 3137 3138 3139 3140 3141 3142 3143 3144 3145 3146 3147 3148 3149 3150 3151 3152 3153 3154 3155 3156 3157 3158 3159 3160 3161 3162 3163 3164 3165 3166 3167 3168 3169 3170 3171 3172 3173 3174 3175 3176 3177 3178 3179 3180 3181 3182 3183 3184 3185 3186 3187 3188 3189 3190 3191 3192 3193 3194 3195 3196 3197 3198 3199 3200 3201 3202 3203 3204 3205 3206 3207 3208 3209 3210 3211 3212 3213 3214 3215 3216 3217 3218 3219 3220 3221 3222 3223 3224 3225 3226 3227 3228 3229 3230 3231 3232 3233 3234 3235 3236 3237 3238 3239 3240 3241 3242 3243 3244 3245 3246 3247 3248 3249 3250 3251 3252 3253 3254 3255 3256 3257 3258 3259 3260 3261 3262 3263 3264 3265 3266 3267 3268 3269 3270 3271 3272 3273 3274 3275 3276 3277 3278 3279 3280 3281 3282 3283 3284 3285 3286 3287 3288 3289 3290 3291 3292 3293 3294 3295 3296 3297 3298 3299 3300 3301 3302 3303 3304 3305 3306 3307 3308 3309 3310 3311 3312 3313 3314 3315 3316 3317 3318 3319 3320 3321 3322 3323 3324 3325 3326 3327 3328 3329 3330 3331 3332 3333 3334 3335 3336 3337 3338 3339 3340 3341 3342 3343 3344 3345 3346 3347 3348 3349 3350 3351 3352 3353 3354 3355 3356 3357 3358 3359 3360 3361 3362 3363 3364 3365 3366 3367 3368 3369 3370 3371 3372 3373 3374 3375 3376 3377 3378 3379 3380 3381 3382 3383 3384 3385 3386 3387 3388 3389 3390 3391 3392 3393 3394 3395 3396 3397 3398 3399 3400 3401 3402 3403 3404 3405 3406 3407 3408 3409 3410 3411 3412 3413 3414 3415 3416 3417 3418 3419 3420 3421 3422 3423 3424 3425 3426 3427 3428 3429 3430 3431 3432 3433 3434 3435 3436 3437 3438 3439 3440 3441 3442 3443 3444 3445 3446 3447 3448 3449 3450 3451 3452 3453 3454 3455 3456 3457 3458 3459 3460 3461 3462 3463 3464 3465 3466 3467 3468 3469 3470 3471 3472 3473 3474 3475 3476 3477 3478 3479 3480 3481 3482 3483 3484 3485 3486 3487 3488 3489 3490 3491 3492 3493 3494 3495 3496 3497 3498 3499 3500 3501 3502 3503 3504 3505 3506 3507 3508 3509 3510 3511 3512 3513 3514 3515 3516 3517 3518 3519 3520 3521 3522 3523 3524 3525 3526 3527 3528 3529 3530 3531 3532 3533 3534 3535 3536 3537 3538 3539 3540 3541 3542 3543 3544 3545 3546 3547 3548 3549 3550 3551 3552 3553 3554 3555 3556 3557 3558 3559 3560 3561 3562 3563 3564 3565 3566 3567 3568 3569 3570 3571 3572 3573 3574 3575 3576 3577 3578 3579 3580 3581 3582 3583 3584 3585 3586 3587 3588 3589 3590 3591 3592 3593 3594 3595 3596 3597 3598 3599 3600 3601 3602 3603 3604 3605 3606 3607 3608 3609 3610 3611 3612 3613 3614 3615 3616 3617 3618 3619 3620 3621 3622 3623 3624 3625 3626 3627 3628 3629 3630 3631 3632 3633 3634 3635 3636 3637 3638 3639 3640 3641 3642 3643
				    sizeof(struct iscsi_hdr));

	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);