[SCSI] cxgb3i: Add cxgb3i iSCSI driver.

This patch implements the cxgb3i iscsi connection acceleration for the
open-iscsi initiator.

The cxgb3i driver offers the iscsi PDU based offload:
- digest insertion and verification
- payload direct-placement into host memory buffer.
Signed-off-by: NKaren Xie <kxie@chelsio.com>
Signed-off-by: NJames Bottomley <James.Bottomley@HansenPartnership.com>

Documentation/scsi/cxgb3i.txt

+Chelsio S3 iSCSI Driver for Linux
+
+Introduction
+============
+
+The Chelsio T3 ASIC based Adapters (S310, S320, S302, S304, Mezz cards, etc.
+series of products) supports iSCSI acceleration and iSCSI Direct Data Placement
+(DDP) where the hardware handles the expensive byte touching operations, such
+as CRC computation and verification, and direct DMA to the final host memory
+destination:
+
+	- iSCSI PDU digest generation and verification
+
+	  On transmitting, Chelsio S3 h/w computes and inserts the Header and
+	  Data digest into the PDUs.
+	  On receiving, Chelsio S3 h/w computes and verifies the Header and
+	  Data digest of the PDUs.
+
+	- Direct Data Placement (DDP)
+
+	  S3 h/w can directly place the iSCSI Data-In or Data-Out PDU's
+	  payload into pre-posted final destination host-memory buffers based
+	  on the Initiator Task Tag (ITT) in Data-In or Target Task Tag (TTT)
+	  in Data-Out PDUs.
+
+	- PDU Transmit and Recovery
+
+	  On transmitting, S3 h/w accepts the complete PDU (header + data)
+	  from the host driver, computes and inserts the digests, decomposes
+	  the PDU into multiple TCP segments if necessary, and transmit all
+	  the TCP segments onto the wire. It handles TCP retransmission if
+	  needed.
+
+	  On receving, S3 h/w recovers the iSCSI PDU by reassembling TCP
+	  segments, separating the header and data, calculating and verifying
+	  the digests, then forwards the header to the host. The payload data,
+	  if possible, will be directly placed into the pre-posted host DDP
+	  buffer. Otherwise, the payload data will be sent to the host too.
+
+The cxgb3i driver interfaces with open-iscsi initiator and provides the iSCSI
+acceleration through Chelsio hardware wherever applicable.
+
+Using the cxgb3i Driver
+=======================
+
+The following steps need to be taken to accelerates the open-iscsi initiator:
+
+1. Load the cxgb3i driver: "modprobe cxgb3i"
+
+   The cxgb3i module registers a new transport class "cxgb3i" with open-iscsi.
+
+   * in the case of recompiling the kernel, the cxgb3i selection is located at
+	Device Drivers
+		SCSI device support --->
+			[*] SCSI low-level drivers  --->
+				<M>   Chelsio S3xx iSCSI support
+
+2. Create an interface file located under /etc/iscsi/ifaces/ for the new
+   transport class "cxgb3i".
+
+   The content of the file should be in the following format:
+	iface.transport_name = cxgb3i
+	iface.net_ifacename = <ethX>
+	iface.ipaddress = <iscsi ip address>
+
+   * if iface.ipaddress is specified, <iscsi ip address> needs to be either the
+	same as the ethX's ip address or an address on the same subnet. Make
+	sure the ip address is unique in the network.
+
+3. edit /etc/iscsi/iscsid.conf
+   The default setting for MaxRecvDataSegmentLength (131072) is too big,
+   replace "node.conn[0].iscsi.MaxRecvDataSegmentLength" to be a value no
+   bigger than 15360 (for example 8192):
+
+	node.conn[0].iscsi.MaxRecvDataSegmentLength = 8192
+
+   * The login would fail for a normal session if MaxRecvDataSegmentLength is
+	too big.  A error message in the format of
+	"cxgb3i: ERR! MaxRecvSegmentLength <X> too big. Need to be <= <Y>."
+	would be logged to dmesg.
+
+4. To direct open-iscsi traffic to go through cxgb3i's accelerated path,
+   "-I <iface file name>" option needs to be specified with most of the
+   iscsiadm command. <iface file name> is the transport interface file created
+   in step 2.

drivers/scsi/Kconfig

@@ -352,6 +352,8 @@ config ISCSI_TCP
 
 	 http://open-iscsi.org
 
+source "drivers/scsi/cxgb3i/Kconfig"
+
 config SGIWD93_SCSI
 	tristate "SGI WD93C93 SCSI Driver"
 	depends on SGI_HAS_WD93 && SCSI

drivers/scsi/Makefile

@@ -126,6 +126,7 @@ obj-$(CONFIG_SCSI_HPTIOP)	+= hptiop.o
 obj-$(CONFIG_SCSI_STEX)		+= stex.o
 obj-$(CONFIG_SCSI_MVSAS)	+= mvsas.o
 obj-$(CONFIG_PS3_ROM)		+= ps3rom.o
+obj-$(CONFIG_SCSI_CXGB3_ISCSI)	+= libiscsi.o libiscsi_tcp.o cxgb3i/
 
 obj-$(CONFIG_ARM)		+= arm/
 

drivers/scsi/cxgb3i/Kbuild

+EXTRA_CFLAGS += -I$(TOPDIR)/drivers/net/cxgb3
+
+cxgb3i-y := cxgb3i_init.o cxgb3i_iscsi.o cxgb3i_pdu.o cxgb3i_offload.o
+obj-$(CONFIG_SCSI_CXGB3_ISCSI) += cxgb3i_ddp.o cxgb3i.o

drivers/scsi/cxgb3i/Kconfig

+config SCSI_CXGB3_ISCSI
+	tristate "Chelsio S3xx iSCSI support"
+	select CHELSIO_T3
+	select SCSI_ISCSI_ATTRS
+	---help---
+	This driver supports iSCSI offload for the Chelsio S3 series devices.

drivers/scsi/cxgb3i/cxgb3i.h

+/*
+ * cxgb3i.h: Chelsio S3xx iSCSI driver.
+ *
+ * Copyright (c) 2008 Chelsio Communications, Inc.
+ *
+ * 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.
+ *
+ * Written by: Karen Xie (kxie@chelsio.com)
+ */
+
+#ifndef __CXGB3I_H__
+#define __CXGB3I_H__
+
+#include <linux/module.h>
+#include <linux/moduleparam.h>
+#include <linux/errno.h>
+#include <linux/types.h>
+#include <linux/list.h>
+#include <linux/netdevice.h>
+#include <linux/scatterlist.h>
+#include <scsi/libiscsi_tcp.h>
+
+/* from cxgb3 LLD */
+#include "common.h"
+#include "t3_cpl.h"
+#include "t3cdev.h"
+#include "cxgb3_ctl_defs.h"
+#include "cxgb3_offload.h"
+#include "firmware_exports.h"
+
+#include "cxgb3i_offload.h"
+#include "cxgb3i_ddp.h"
+
+#define CXGB3I_SCSI_QDEPTH_DFLT	128
+#define CXGB3I_MAX_TARGET	CXGB3I_MAX_CONN
+#define CXGB3I_MAX_LUN		512
+#define ISCSI_PDU_NONPAYLOAD_MAX \
+	(sizeof(struct iscsi_hdr) + ISCSI_MAX_AHS_SIZE + 2*ISCSI_DIGEST_SIZE)
+
+struct cxgb3i_adapter;
+struct cxgb3i_hba;
+struct cxgb3i_endpoint;
+
+/**
+ * struct cxgb3i_hba - cxgb3i iscsi structure (per port)
+ *
+ * @snic:	cxgb3i adapter containing this port
+ * @ndev:	pointer to netdev structure
+ * @shost:	pointer to scsi host structure
+ */
+struct cxgb3i_hba {
+	struct cxgb3i_adapter *snic;
+	struct net_device *ndev;
+	struct Scsi_Host *shost;
+};
+
+/**
+ * struct cxgb3i_adapter - cxgb3i adapter structure (per pci)
+ *
+ * @listhead:	list head to link elements
+ * @lock:	lock for this structure
+ * @tdev:	pointer to t3cdev used by cxgb3 driver
+ * @pdev:	pointer to pci dev
+ * @hba_cnt:	# of hbas (the same as # of ports)
+ * @hba:	all the hbas on this adapter
+ * @tx_max_size: max. tx packet size supported
+ * @rx_max_size: max. rx packet size supported
+ * @tag_format: ddp tag format settings
+ */
+struct cxgb3i_adapter {
+	struct list_head list_head;
+	spinlock_t lock;
+	struct t3cdev *tdev;
+	struct pci_dev *pdev;
+	unsigned char hba_cnt;
+	struct cxgb3i_hba *hba[MAX_NPORTS];
+
+	unsigned int tx_max_size;
+	unsigned int rx_max_size;
+
+	struct cxgb3i_tag_format tag_format;
+};
+
+/**
+ * struct cxgb3i_conn - cxgb3i iscsi connection
+ *
+ * @listhead:	list head to link elements
+ * @cep:	pointer to iscsi_endpoint structure
+ * @conn:	pointer to iscsi_conn structure
+ * @hba:	pointer to the hba this conn. is going through
+ * @task_idx_bits: # of bits needed for session->cmds_max
+ */
+struct cxgb3i_conn {
+	struct list_head list_head;
+	struct cxgb3i_endpoint *cep;
+	struct iscsi_conn *conn;
+	struct cxgb3i_hba *hba;
+	unsigned int task_idx_bits;
+};
+
+/**
+ * struct cxgb3i_endpoint - iscsi tcp endpoint
+ *
+ * @c3cn:	the h/w tcp connection representation
+ * @hba:	pointer to the hba this conn. is going through
+ * @cconn:	pointer to the associated cxgb3i iscsi connection
+ */
+struct cxgb3i_endpoint {
+	struct s3_conn *c3cn;
+	struct cxgb3i_hba *hba;
+	struct cxgb3i_conn *cconn;
+};
+
+int cxgb3i_iscsi_init(void);
+void cxgb3i_iscsi_cleanup(void);
+
+struct cxgb3i_adapter *cxgb3i_adapter_add(struct t3cdev *);
+void cxgb3i_adapter_remove(struct t3cdev *);
+int cxgb3i_adapter_ulp_init(struct cxgb3i_adapter *);
+void cxgb3i_adapter_ulp_cleanup(struct cxgb3i_adapter *);
+
+struct cxgb3i_hba *cxgb3i_hba_find_by_netdev(struct net_device *);
+struct cxgb3i_hba *cxgb3i_hba_host_add(struct cxgb3i_adapter *,
+				       struct net_device *);
+void cxgb3i_hba_host_remove(struct cxgb3i_hba *);
+
+int cxgb3i_pdu_init(void);
+void cxgb3i_pdu_cleanup(void);
+void cxgb3i_conn_cleanup_task(struct iscsi_task *);
+int cxgb3i_conn_alloc_pdu(struct iscsi_task *, u8);
+int cxgb3i_conn_init_pdu(struct iscsi_task *, unsigned int, unsigned int);
+int cxgb3i_conn_xmit_pdu(struct iscsi_task *);
+
+void cxgb3i_release_itt(struct iscsi_task *task, itt_t hdr_itt);
+int cxgb3i_reserve_itt(struct iscsi_task *task, itt_t *hdr_itt);
+
+#endif

drivers/scsi/cxgb3i/cxgb3i_ddp.h

+/*
+ * cxgb3i_ddp.h: Chelsio S3xx iSCSI DDP Manager.
+ *
+ * Copyright (c) 2008 Chelsio Communications, Inc.
+ *
+ * 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.
+ *
+ * Written by: Karen Xie (kxie@chelsio.com)
+ */
+
+#ifndef __CXGB3I_ULP2_DDP_H__
+#define __CXGB3I_ULP2_DDP_H__
+
+/**
+ * struct cxgb3i_tag_format - cxgb3i ulp tag format for an iscsi entity
+ *
+ * @sw_bits:	# of bits used by iscsi software layer
+ * @rsvd_bits:	# of bits used by h/w
+ * @rsvd_shift:	h/w bits shift left
+ * @rsvd_mask:	reserved bit mask
+ */
+struct cxgb3i_tag_format {
+	unsigned char sw_bits;
+	unsigned char rsvd_bits;
+	unsigned char rsvd_shift;
+	unsigned char filler[1];
+	u32 rsvd_mask;
+};
+
+/**
+ * struct cxgb3i_gather_list - cxgb3i direct data placement memory
+ *
+ * @tag:	ddp tag
+ * @length:	total data buffer length
+ * @offset:	initial offset to the 1st page
+ * @nelem:	# of pages
+ * @pages:	page pointers
+ * @phys_addr:	physical address
+ */
+struct cxgb3i_gather_list {
+	u32 tag;
+	unsigned int length;
+	unsigned int offset;
+	unsigned int nelem;
+	struct page **pages;
+	dma_addr_t phys_addr[0];
+};
+
+/**
+ * struct cxgb3i_ddp_info - cxgb3i direct data placement for pdu payload
+ *
+ * @list:	list head to link elements
+ * @tdev:	pointer to t3cdev used by cxgb3 driver
+ * @max_txsz:	max tx packet size for ddp
+ * @max_rxsz:	max rx packet size for ddp
+ * @llimit:	lower bound of the page pod memory
+ * @ulimit:	upper bound of the page pod memory
+ * @nppods:	# of page pod entries
+ * @idx_last:	page pod entry last used
+ * @idx_bits:	# of bits the pagepod index would take
+ * @idx_mask:	pagepod index mask
+ * @rsvd_tag_mask: tag mask
+ * @map_lock:	lock to synchonize access to the page pod map
+ * @gl_map:	ddp memory gather list
+ * @gl_skb:	skb used to program the pagepod
+ */
+struct cxgb3i_ddp_info {
+	struct list_head list;
+	struct t3cdev *tdev;
+	struct pci_dev *pdev;
+	unsigned int max_txsz;
+	unsigned int max_rxsz;
+	unsigned int llimit;
+	unsigned int ulimit;
+	unsigned int nppods;
+	unsigned int idx_last;
+	unsigned char idx_bits;
+	unsigned char filler[3];
+	u32 idx_mask;
+	u32 rsvd_tag_mask;
+	spinlock_t map_lock;
+	struct cxgb3i_gather_list **gl_map;
+	struct sk_buff **gl_skb;
+};
+
+#define ULP2_MAX_PKT_SIZE	16224
+#define ULP2_MAX_PDU_PAYLOAD	(ULP2_MAX_PKT_SIZE - ISCSI_PDU_NONPAYLOAD_MAX)
+#define PPOD_PAGES_MAX		4
+#define PPOD_PAGES_SHIFT	2	/* 4 pages per pod */
+
+/*
+ * struct pagepod_hdr, pagepod - pagepod format
+ */
+struct pagepod_hdr {
+	u32 vld_tid;
+	u32 pgsz_tag_clr;
+	u32 maxoffset;
+	u32 pgoffset;
+	u64 rsvd;
+};
+
+struct pagepod {
+	struct pagepod_hdr hdr;
+	u64 addr[PPOD_PAGES_MAX + 1];
+};
+
+#define PPOD_SIZE		sizeof(struct pagepod)	/* 64 */
+#define PPOD_SIZE_SHIFT		6
+
+#define PPOD_COLOR_SHIFT	0
+#define PPOD_COLOR_SIZE		6
+#define PPOD_COLOR_MASK		((1 << PPOD_COLOR_SIZE) - 1)
+
+#define PPOD_IDX_SHIFT		PPOD_COLOR_SIZE
+#define PPOD_IDX_MAX_SIZE	24
+
+#define S_PPOD_TID    0
+#define M_PPOD_TID    0xFFFFFF
+#define V_PPOD_TID(x) ((x) << S_PPOD_TID)
+
+#define S_PPOD_VALID    24
+#define V_PPOD_VALID(x) ((x) << S_PPOD_VALID)
+#define F_PPOD_VALID    V_PPOD_VALID(1U)
+
+#define S_PPOD_COLOR    0
+#define M_PPOD_COLOR    0x3F
+#define V_PPOD_COLOR(x) ((x) << S_PPOD_COLOR)
+
+#define S_PPOD_TAG    6
+#define M_PPOD_TAG    0xFFFFFF
+#define V_PPOD_TAG(x) ((x) << S_PPOD_TAG)
+
+#define S_PPOD_PGSZ    30
+#define M_PPOD_PGSZ    0x3
+#define V_PPOD_PGSZ(x) ((x) << S_PPOD_PGSZ)
+
+/*
+ * large memory chunk allocation/release
+ * use vmalloc() if kmalloc() fails
+ */
+static inline void *cxgb3i_alloc_big_mem(unsigned int size,
+					 gfp_t gfp)
+{
+	void *p = kmalloc(size, gfp);
+	if (!p)
+		p = vmalloc(size);
+	if (p)
+		memset(p, 0, size);
+	return p;
+}
+
+static inline void cxgb3i_free_big_mem(void *addr)
+{
+	if (is_vmalloc_addr(addr))
+		vfree(addr);
+	else
+		kfree(addr);
+}
+
+/*
+ * cxgb3i ddp tag are 32 bits, it consists of reserved bits used by h/w and
+ * non-reserved bits that can be used by the iscsi s/w.
+ * The reserved bits are identified by the rsvd_bits and rsvd_shift fields
+ * in struct cxgb3i_tag_format.
+ *
+ * The upper most reserved bit can be used to check if a tag is ddp tag or not:
+ * 	if the bit is 0, the tag is a valid ddp tag
+ */
+
+/**
+ * cxgb3i_is_ddp_tag - check if a given tag is a hw/ddp tag
+ * @tformat: tag format information
+ * @tag: tag to be checked
+ *
+ * return true if the tag is a ddp tag, false otherwise.
+ */
+static inline int cxgb3i_is_ddp_tag(struct cxgb3i_tag_format *tformat, u32 tag)
+{
+	return !(tag & (1 << (tformat->rsvd_bits + tformat->rsvd_shift - 1)));
+}
+
+/**
+ * cxgb3i_sw_tag_usable - check if a given s/w tag has enough bits left for
+ *			  the reserved/hw bits
+ * @tformat: tag format information
+ * @sw_tag: s/w tag to be checked
+ *
+ * return true if the tag is a ddp tag, false otherwise.
+ */
+static inline int cxgb3i_sw_tag_usable(struct cxgb3i_tag_format *tformat,
+					u32 sw_tag)
+{
+	sw_tag >>= (32 - tformat->rsvd_bits);
+	return !sw_tag;
+}
+
+/**
+ * cxgb3i_set_non_ddp_tag - mark a given s/w tag as an invalid ddp tag
+ * @tformat: tag format information
+ * @sw_tag: s/w tag to be checked
+ *
+ * insert 1 at the upper most reserved bit to mark it as an invalid ddp tag.
+ */
+static inline u32 cxgb3i_set_non_ddp_tag(struct cxgb3i_tag_format *tformat,
+					 u32 sw_tag)
+{
+	unsigned char shift = tformat->rsvd_bits + tformat->rsvd_shift - 1;
+	u32 mask = (1 << shift) - 1;
+
+	if (sw_tag && (sw_tag & ~mask)) {
+		u32 v1 = sw_tag & ((1 << shift) - 1);
+		u32 v2 = (sw_tag >> (shift - 1)) << shift;
+
+		return v2 | v1 | 1 << shift;
+	}
+	return sw_tag | 1 << shift;
+}
+
+/**
+ * cxgb3i_ddp_tag_base - shift the s/w tag bits so that reserved bits are not
+ *			 used.
+ * @tformat: tag format information
+ * @sw_tag: s/w tag to be checked
+ */
+static inline u32 cxgb3i_ddp_tag_base(struct cxgb3i_tag_format *tformat,
+				      u32 sw_tag)
+{
+	u32 mask = (1 << tformat->rsvd_shift) - 1;
+
+	if (sw_tag && (sw_tag & ~mask)) {
+		u32 v1 = sw_tag & mask;
+		u32 v2 = sw_tag >> tformat->rsvd_shift;
+
+		v2 <<= tformat->rsvd_shift + tformat->rsvd_bits;
+		return v2 | v1;
+	}
+	return sw_tag;
+}
+
+/**
+ * cxgb3i_tag_rsvd_bits - get the reserved bits used by the h/w
+ * @tformat: tag format information
+ * @tag: tag to be checked
+ *
+ * return the reserved bits in the tag
+ */
+static inline u32 cxgb3i_tag_rsvd_bits(struct cxgb3i_tag_format *tformat,
+				       u32 tag)
+{
+	if (cxgb3i_is_ddp_tag(tformat, tag))
+		return (tag >> tformat->rsvd_shift) & tformat->rsvd_mask;
+	return 0;
+}
+
+/**
+ * cxgb3i_tag_nonrsvd_bits - get the non-reserved bits used by the s/w
+ * @tformat: tag format information
+ * @tag: tag to be checked
+ *
+ * return the non-reserved bits in the tag.
+ */
+static inline u32 cxgb3i_tag_nonrsvd_bits(struct cxgb3i_tag_format *tformat,
+					  u32 tag)
+{
+	unsigned char shift = tformat->rsvd_bits + tformat->rsvd_shift - 1;
+	u32 v1, v2;
+
+	if (cxgb3i_is_ddp_tag(tformat, tag)) {
+		v1 = tag & ((1 << tformat->rsvd_shift) - 1);
+		v2 = (tag >> (shift + 1)) << tformat->rsvd_shift;
+	} else {
+		u32 mask = (1 << shift) - 1;
+
+		tag &= ~(1 << shift);
+		v1 = tag & mask;
+		v2 = (tag >> 1) & ~mask;
+	}
+	return v1 | v2;
+}
+
+int cxgb3i_ddp_tag_reserve(struct t3cdev *, unsigned int tid,
+			   struct cxgb3i_tag_format *, u32 *tag,
+			   struct cxgb3i_gather_list *, gfp_t gfp);
+void cxgb3i_ddp_tag_release(struct t3cdev *, u32 tag);
+
+struct cxgb3i_gather_list *cxgb3i_ddp_make_gl(unsigned int xferlen,
+				struct scatterlist *sgl,
+				unsigned int sgcnt,
+				struct pci_dev *pdev,
+				gfp_t gfp);
+void cxgb3i_ddp_release_gl(struct cxgb3i_gather_list *gl,
+				struct pci_dev *pdev);
+
+int cxgb3i_setup_conn_host_pagesize(struct t3cdev *, unsigned int tid,
+				    int reply);
+int cxgb3i_setup_conn_pagesize(struct t3cdev *, unsigned int tid, int reply,
+			       unsigned long pgsz);
+int cxgb3i_setup_conn_digest(struct t3cdev *, unsigned int tid,
+				int hcrc, int dcrc, int reply);
+int cxgb3i_ddp_find_page_index(unsigned long pgsz);
+int cxgb3i_adapter_ddp_init(struct t3cdev *, struct cxgb3i_tag_format *,
+			    unsigned int *txsz, unsigned int *rxsz);
+void cxgb3i_adapter_ddp_cleanup(struct t3cdev *);
+#endif

drivers/scsi/cxgb3i/cxgb3i_init.c

+/* cxgb3i_init.c: Chelsio S3xx iSCSI driver.
+ *
+ * Copyright (c) 2008 Chelsio Communications, Inc.
+ *
+ * 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.
+ *
+ * Written by: Karen Xie (kxie@chelsio.com)
+ */
+
+#include "cxgb3i.h"
+
+#define DRV_MODULE_NAME         "cxgb3i"
+#define DRV_MODULE_VERSION	"1.0.0"
+#define DRV_MODULE_RELDATE	"Jun. 1, 2008"
+
+static char version[] =
+	"Chelsio S3xx iSCSI Driver " DRV_MODULE_NAME
+	" v" DRV_MODULE_VERSION " (" DRV_MODULE_RELDATE ")\n";
+
+MODULE_AUTHOR("Karen Xie <kxie@chelsio.com>");
+MODULE_DESCRIPTION("Chelsio S3xx iSCSI Driver");
+MODULE_LICENSE("GPL");
+MODULE_VERSION(DRV_MODULE_VERSION);
+
+static void open_s3_dev(struct t3cdev *);
+static void close_s3_dev(struct t3cdev *);
+
+static cxgb3_cpl_handler_func cxgb3i_cpl_handlers[NUM_CPL_CMDS];
+static struct cxgb3_client t3c_client = {
+	.name = "iscsi_cxgb3",
+	.handlers = cxgb3i_cpl_handlers,
+	.add = open_s3_dev,
+	.remove = close_s3_dev,
+};
+
+/**
+ * open_s3_dev - register with cxgb3 LLD
+ * @t3dev:	cxgb3 adapter instance
+ */
+static void open_s3_dev(struct t3cdev *t3dev)
+{
+	static int vers_printed;
+
+	if (!vers_printed) {
+		printk(KERN_INFO "%s", version);
+		vers_printed = 1;
+	}
+
+	cxgb3i_sdev_add(t3dev, &t3c_client);
+	cxgb3i_adapter_add(t3dev);
+}
+
+/**
+ * close_s3_dev - de-register with cxgb3 LLD
+ * @t3dev:	cxgb3 adapter instance
+ */
+static void close_s3_dev(struct t3cdev *t3dev)
+{
+	cxgb3i_adapter_remove(t3dev);
+	cxgb3i_sdev_remove(t3dev);
+}
+
+/**
+ * cxgb3i_init_module - module init entry point
+ *
+ * initialize any driver wide global data structures and register itself
+ *	with the cxgb3 module
+ */
+static int __init cxgb3i_init_module(void)
+{
+	int err;
+
+	err = cxgb3i_sdev_init(cxgb3i_cpl_handlers);
+	if (err < 0)
+		return err;
+
+	err = cxgb3i_iscsi_init();
+	if (err < 0)
+		return err;
+
+	err = cxgb3i_pdu_init();
+	if (err < 0)
+		return err;
+
+	cxgb3_register_client(&t3c_client);
+
+	return 0;
+}
+
+/**
+ * cxgb3i_exit_module - module cleanup/exit entry point
+ *
+ * go through the driver hba list and for each hba, release any resource held.
+ *	and unregisters iscsi transport and the cxgb3 module
+ */
+static void __exit cxgb3i_exit_module(void)
+{
+	cxgb3_unregister_client(&t3c_client);
+	cxgb3i_pdu_cleanup();
+	cxgb3i_iscsi_cleanup();
+	cxgb3i_sdev_cleanup();
+}
+
+module_init(cxgb3i_init_module);
+module_exit(cxgb3i_exit_module);

drivers/scsi/cxgb3i/cxgb3i_offload.h

+/*
+ * cxgb3i_offload.h: Chelsio S3xx iscsi offloaded tcp connection management
+ *
+ * Copyright (C) 2003-2008 Chelsio Communications.  All rights reserved.
+ *
+ * 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 LICENSE file included in this
+ * release for licensing terms and conditions.
+ *
+ * Written by:	Dimitris Michailidis (dm@chelsio.com)
+ *		Karen Xie (kxie@chelsio.com)
+ */
+
+#ifndef _CXGB3I_OFFLOAD_H
+#define _CXGB3I_OFFLOAD_H
+
+#include <linux/skbuff.h>
+#include <net/tcp.h>
+
+#include "common.h"
+#include "adapter.h"
+#include "t3cdev.h"
+#include "cxgb3_offload.h"
+
+#define cxgb3i_log_error(fmt...) printk(KERN_ERR "cxgb3i: ERR! " fmt)
+#define cxgb3i_log_warn(fmt...)	 printk(KERN_WARNING "cxgb3i: WARN! " fmt)
+#define cxgb3i_log_info(fmt...)  printk(KERN_INFO "cxgb3i: " fmt)
+#define cxgb3i_log_debug(fmt, args...) \
+	printk(KERN_INFO "cxgb3i: %s - " fmt, __func__ , ## args)
+
+/**
+ * struct s3_conn - an iscsi tcp connection structure
+ *
+ * @dev:	net device of with connection
+ * @cdev:	adapter t3cdev for net device
+ * @flags:	see c3cn_flags below
+ * @tid:	connection id assigned by the h/w
+ * @qset:	queue set used by connection
+ * @mss_idx:	Maximum Segment Size table index
+ * @l2t:	ARP resolution entry for offload packets
+ * @wr_max:	maximum in-flight writes
+ * @wr_avail:	number of writes available
+ * @wr_unacked:	writes since last request for completion notification
+ * @wr_pending_head: head of pending write queue
+ * @wr_pending_tail: tail of pending write queue
+ * @cpl_close:	skb for cpl_close_req
+ * @cpl_abort_req: skb for cpl_abort_req
+ * @cpl_abort_rpl: skb for cpl_abort_rpl
+ * @lock:	connection status lock
+ * @refcnt:	reference count on connection
+ * @state:	connection state
+ * @saddr:	source ip/port address
+ * @daddr:	destination ip/port address
+ * @dst_cache:	reference to destination route
+ * @receive_queue: received PDUs
+ * @write_queue: un-pushed pending writes
+ * @retry_timer: retry timer for various operations
+ * @err:	connection error status
+ * @callback_lock: lock for opaque user context
+ * @user_data:	opaque user context
+ * @rcv_nxt:	next receive seq. #
+ * @copied_seq:	head of yet unread data
+ * @rcv_wup:	rcv_nxt on last window update sent
+ * @snd_nxt:	next sequence we send
+ * @snd_una:	first byte we want an ack for
+ * @write_seq:	tail+1 of data held in send buffer
+ */
+struct s3_conn {
+	struct net_device *dev;
+	struct t3cdev *cdev;
+	unsigned long flags;
+	int tid;
+	int qset;
+	int mss_idx;
+	struct l2t_entry *l2t;
+	int wr_max;
+	int wr_avail;
+	int wr_unacked;
+	struct sk_buff *wr_pending_head;
+	struct sk_buff *wr_pending_tail;
+	struct sk_buff *cpl_close;
+	struct sk_buff *cpl_abort_req;
+	struct sk_buff *cpl_abort_rpl;
+	spinlock_t lock;
+	atomic_t refcnt;
+	volatile unsigned int state;
+	struct sockaddr_in saddr;
+	struct sockaddr_in daddr;
+	struct dst_entry *dst_cache;
+	struct sk_buff_head receive_queue;
+	struct sk_buff_head write_queue;
+	struct timer_list retry_timer;
+	int err;
+	rwlock_t callback_lock;
+	void *user_data;
+
+	u32 rcv_nxt;
+	u32 copied_seq;
+	u32 rcv_wup;
+	u32 snd_nxt;
+	u32 snd_una;
+	u32 write_seq;
+};
+
+/*
+ * connection state
+ */
+enum conn_states {
+	C3CN_STATE_CONNECTING = 1,
+	C3CN_STATE_ESTABLISHED,
+	C3CN_STATE_ACTIVE_CLOSE,
+	C3CN_STATE_PASSIVE_CLOSE,
+	C3CN_STATE_CLOSE_WAIT_1,
+	C3CN_STATE_CLOSE_WAIT_2,
+	C3CN_STATE_ABORTING,
+	C3CN_STATE_CLOSED,
+};
+
+static inline unsigned int c3cn_is_closing(const struct s3_conn *c3cn)
+{
+	return c3cn->state >= C3CN_STATE_ACTIVE_CLOSE;
+}
+static inline unsigned int c3cn_is_established(const struct s3_conn *c3cn)
+{
+	return c3cn->state == C3CN_STATE_ESTABLISHED;
+}
+
+/*
+ * Connection flags -- many to track some close related events.
+ */
+enum c3cn_flags {
+	C3CN_ABORT_RPL_RCVD,	/* received one ABORT_RPL_RSS message */
+	C3CN_ABORT_REQ_RCVD,	/* received one ABORT_REQ_RSS message */
+	C3CN_ABORT_RPL_PENDING,	/* expecting an abort reply */
+	C3CN_TX_DATA_SENT,	/* already sent a TX_DATA WR */
+	C3CN_ACTIVE_CLOSE_NEEDED,	/* need to be closed */
+};
+
+/**
+ * cxgb3i_sdev_data - Per adapter data.
+ * Linked off of each Ethernet device port on the adapter.
+ * Also available via the t3cdev structure since we have pointers to our port
+ * net_device's there ...
+ *
+ * @list:	list head to link elements
+ * @cdev:	t3cdev adapter
+ * @client:	CPL client pointer
+ * @ports:	array of adapter ports
+ * @sport_map_next: next index into the port map
+ * @sport_map:	source port map
+ */
+struct cxgb3i_sdev_data {
+	struct list_head list;
+	struct t3cdev *cdev;
+	struct cxgb3_client *client;
+	struct adap_ports ports;
+	unsigned int sport_map_next;
+	unsigned long sport_map[0];
+};
+#define NDEV2CDATA(ndev) (*(struct cxgb3i_sdev_data **)&(ndev)->ec_ptr)
+#define CXGB3_SDEV_DATA(cdev) NDEV2CDATA((cdev)->lldev)
+
+void cxgb3i_sdev_cleanup(void);
+int cxgb3i_sdev_init(cxgb3_cpl_handler_func *);
+void cxgb3i_sdev_add(struct t3cdev *, struct cxgb3_client *);
+void cxgb3i_sdev_remove(struct t3cdev *);
+
+struct s3_conn *cxgb3i_c3cn_create(void);
+int cxgb3i_c3cn_connect(struct s3_conn *, struct sockaddr_in *);
+void cxgb3i_c3cn_rx_credits(struct s3_conn *, int);
+int cxgb3i_c3cn_send_pdus(struct s3_conn *, struct sk_buff *);
+void cxgb3i_c3cn_release(struct s3_conn *);
+
+/**
+ * cxgb3_skb_cb - control block for received pdu state and ULP mode management.
+ *
+ * @flag:	see C3CB_FLAG_* below
+ * @ulp_mode:	ULP mode/submode of sk_buff
+ * @seq:	tcp sequence number
+ * @ddigest:	pdu data digest
+ * @pdulen:	recovered pdu length
+ * @ulp_data:	scratch area for ULP
+ */
+struct cxgb3_skb_cb {
+	__u8 flags;
+	__u8 ulp_mode;
+	__u32 seq;
+	__u32 ddigest;
+	__u32 pdulen;
+	__u8 ulp_data[16];
+};
+
+#define CXGB3_SKB_CB(skb)	((struct cxgb3_skb_cb *)&((skb)->cb[0]))
+
+#define skb_ulp_mode(skb)	(CXGB3_SKB_CB(skb)->ulp_mode)
+#define skb_ulp_ddigest(skb)	(CXGB3_SKB_CB(skb)->ddigest)
+#define skb_ulp_pdulen(skb)	(CXGB3_SKB_CB(skb)->pdulen)
+#define skb_ulp_data(skb)	(CXGB3_SKB_CB(skb)->ulp_data)
+
+enum c3cb_flags {
+	C3CB_FLAG_NEED_HDR = 1 << 0,	/* packet needs a TX_DATA_WR header */
+	C3CB_FLAG_NO_APPEND = 1 << 1,	/* don't grow this skb */
+	C3CB_FLAG_COMPL = 1 << 2,	/* request WR completion */
+};
+
+/**
+ * sge_opaque_hdr -
+ * Opaque version of structure the SGE stores at skb->head of TX_DATA packets
+ * and for which we must reserve space.
+ */
+struct sge_opaque_hdr {
+	void *dev;
+	dma_addr_t addr[MAX_SKB_FRAGS + 1];
+};
+
+/* for TX: a skb must have a headroom of at least TX_HEADER_LEN bytes */
+#define TX_HEADER_LEN \
+		(sizeof(struct tx_data_wr) + sizeof(struct sge_opaque_hdr))
+
+/*
+ * get and set private ip for iscsi traffic
+ */
+#define cxgb3i_get_private_ipv4addr(ndev) \
+	(((struct port_info *)(netdev_priv(ndev)))->iscsi_ipv4addr)
+#define cxgb3i_set_private_ipv4addr(ndev, addr) \
+	(((struct port_info *)(netdev_priv(ndev)))->iscsi_ipv4addr) = addr
+
+/* max. connections per adapter */
+#define CXGB3I_MAX_CONN		16384
+#endif /* _CXGB3_OFFLOAD_H */

drivers/scsi/cxgb3i/cxgb3i_pdu.c

+/*
+ * cxgb3i_pdu.c: Chelsio S3xx iSCSI driver.
+ *
+ * Copyright (c) 2008 Chelsio Communications, Inc.
+ * Copyright (c) 2008 Mike Christie
+ * Copyright (c) 2008 Red Hat, Inc.  All rights reserved.
+ *
+ * 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.
+ *
+ * Written by: Karen Xie (kxie@chelsio.com)
+ */
+
+#include <linux/skbuff.h>
+#include <linux/crypto.h>
+#include <scsi/scsi_cmnd.h>
+#include <scsi/scsi_host.h>
+
+#include "cxgb3i.h"
+#include "cxgb3i_pdu.h"
+
+#ifdef __DEBUG_CXGB3I_RX__
+#define cxgb3i_rx_debug		cxgb3i_log_debug
+#else
+#define cxgb3i_rx_debug(fmt...)
+#endif
+
+#ifdef __DEBUG_CXGB3I_TX__
+#define cxgb3i_tx_debug		cxgb3i_log_debug
+#else
+#define cxgb3i_tx_debug(fmt...)
+#endif
+
+static struct page *pad_page;
+
+/*
+ * pdu receive, interact with libiscsi_tcp
+ */
+static inline int read_pdu_skb(struct iscsi_conn *conn, struct sk_buff *skb,
+			       unsigned int offset, int offloaded)
+{
+	int status = 0;
+	int bytes_read;
+
+	bytes_read = iscsi_tcp_recv_skb(conn, skb, offset, offloaded, &status);
+	switch (status) {
+	case ISCSI_TCP_CONN_ERR:
+		return -EIO;
+	case ISCSI_TCP_SUSPENDED:
+		/* no transfer - just have caller flush queue */
+		return bytes_read;
+	case ISCSI_TCP_SKB_DONE:
+		/*
+		 * pdus should always fit in the skb and we should get
+		 * segment done notifcation.
+		 */
+		iscsi_conn_printk(KERN_ERR, conn, "Invalid pdu or skb.");
+		return -EFAULT;
+	case ISCSI_TCP_SEGMENT_DONE:
+		return bytes_read;
+	default:
+		iscsi_conn_printk(KERN_ERR, conn, "Invalid iscsi_tcp_recv_skb "
+				  "status %d\n", status);
+		return -EINVAL;
+	}
+}
+
+static int cxgb3i_conn_read_pdu_skb(struct iscsi_conn *conn,
+				    struct sk_buff *skb)
+{
+	struct iscsi_tcp_conn *tcp_conn = conn->dd_data;
+	bool offloaded = 0;
+	unsigned int offset;
+	int rc;
+
+	cxgb3i_rx_debug("conn 0x%p, skb 0x%p, len %u, flag 0x%x.\n",
+			conn, skb, skb->len, skb_ulp_mode(skb));
+
+	if (!iscsi_tcp_recv_segment_is_hdr(tcp_conn)) {
+		iscsi_conn_failure(conn, ISCSI_ERR_PROTO);
+		return -EIO;
+	}
+
+	if (conn->hdrdgst_en && (skb_ulp_mode(skb) & ULP2_FLAG_HCRC_ERROR)) {
+		iscsi_conn_failure(conn, ISCSI_ERR_HDR_DGST);
+		return -EIO;
+	}
+
+	if (conn->datadgst_en && (skb_ulp_mode(skb) & ULP2_FLAG_DCRC_ERROR)) {
+		iscsi_conn_failure(conn, ISCSI_ERR_DATA_DGST);
+		return -EIO;
+	}
+
+	/* iscsi hdr */
+	rc = read_pdu_skb(conn, skb, 0, 0);
+	if (rc <= 0)
+		return rc;
+
+	if (iscsi_tcp_recv_segment_is_hdr(tcp_conn))
+		return 0;
+
+	offset = rc;
+	if (conn->hdrdgst_en)
+		offset += ISCSI_DIGEST_SIZE;
+
+	/* iscsi data */
+	if (skb_ulp_mode(skb) & ULP2_FLAG_DATA_DDPED) {
+		cxgb3i_rx_debug("skb 0x%p, opcode 0x%x, data %u, ddp'ed, "
+				"itt 0x%x.\n",
+				skb,
+				tcp_conn->in.hdr->opcode & ISCSI_OPCODE_MASK,
+				tcp_conn->in.datalen,
+				ntohl(tcp_conn->in.hdr->itt));
+		offloaded = 1;
+	} else {
+		cxgb3i_rx_debug("skb 0x%p, opcode 0x%x, data %u, NOT ddp'ed, "
+				"itt 0x%x.\n",
+				skb,
+				tcp_conn->in.hdr->opcode & ISCSI_OPCODE_MASK,
+				tcp_conn->in.datalen,
+				ntohl(tcp_conn->in.hdr->itt));
+		offset += sizeof(struct cpl_iscsi_hdr_norss);
+	}
+
+	rc = read_pdu_skb(conn, skb, offset, offloaded);
+	if (rc < 0)
+		return rc;
+	else
+		return 0;
+}
+
+/*
+ * pdu transmit, interact with libiscsi_tcp
+ */
+static inline void tx_skb_setmode(struct sk_buff *skb, int hcrc, int dcrc)
+{
+	u8 submode = 0;
+
+	if (hcrc)
+		submode |= 1;
+	if (dcrc)
+		submode |= 2;
+	skb_ulp_mode(skb) = (ULP_MODE_ISCSI << 4) | submode;
+}
+
+void cxgb3i_conn_cleanup_task(struct iscsi_task *task)
+{
+	struct iscsi_tcp_task *tcp_task = task->dd_data;
+
+	/* never reached the xmit task callout */
+	if (tcp_task->dd_data)
+		kfree_skb(tcp_task->dd_data);
+	tcp_task->dd_data = NULL;
+
+	/* MNC - Do we need a check in case this is called but
+	 * cxgb3i_conn_alloc_pdu has never been called on the task */
+	cxgb3i_release_itt(task, task->hdr_itt);
+	iscsi_tcp_cleanup_task(task);
+}
+
+/*
+ * We do not support ahs yet
+ */
+int cxgb3i_conn_alloc_pdu(struct iscsi_task *task, u8 opcode)
+{
+	struct iscsi_tcp_task *tcp_task = task->dd_data;
+	struct sk_buff *skb;
+
+	task->hdr = NULL;
+	/* always allocate rooms for AHS */
+	skb = alloc_skb(sizeof(struct iscsi_hdr) + ISCSI_MAX_AHS_SIZE +
+			TX_HEADER_LEN,  GFP_ATOMIC);
+	if (!skb)
+		return -ENOMEM;
+
+	cxgb3i_tx_debug("task 0x%p, opcode 0x%x, skb 0x%p.\n",
+			task, opcode, skb);
+
+	tcp_task->dd_data = skb;
+	skb_reserve(skb, TX_HEADER_LEN);
+	task->hdr = (struct iscsi_hdr *)skb->data;
+	task->hdr_max = sizeof(struct iscsi_hdr);
+
+	/* data_out uses scsi_cmd's itt */
+	if (opcode != ISCSI_OP_SCSI_DATA_OUT)
+		cxgb3i_reserve_itt(task, &task->hdr->itt);
+
+	return 0;
+}
+
+int cxgb3i_conn_init_pdu(struct iscsi_task *task, unsigned int offset,
+			      unsigned int count)
+{
+	struct iscsi_tcp_task *tcp_task = task->dd_data;
+	struct sk_buff *skb = tcp_task->dd_data;
+	struct iscsi_conn *conn = task->conn;
+	struct page *pg;
+	unsigned int datalen = count;
+	int i, padlen = iscsi_padding(count);
+	skb_frag_t *frag;
+
+	cxgb3i_tx_debug("task 0x%p,0x%p, offset %u, count %u, skb 0x%p.\n",
+			task, task->sc, offset, count, skb);
+
+	skb_put(skb, task->hdr_len);
+	tx_skb_setmode(skb, conn->hdrdgst_en, datalen ? conn->datadgst_en : 0);
+	if (!count)
+		return 0;
+
+	if (task->sc) {
+		struct scatterlist *sg;
+		struct scsi_data_buffer *sdb;
+		unsigned int sgoffset = offset;
+		struct page *sgpg;
+		unsigned int sglen;
+
+		sdb = scsi_out(task->sc);
+		sg = sdb->table.sgl;
+
+		for_each_sg(sdb->table.sgl, sg, sdb->table.nents, i) {
+			cxgb3i_tx_debug("sg %d, page 0x%p, len %u offset %u\n",
+					i, sg_page(sg), sg->length, sg->offset);
+
+			if (sgoffset < sg->length)
+				break;
+			sgoffset -= sg->length;
+		}
+		sgpg = sg_page(sg);
+		sglen = sg->length - sgoffset;
+
+		do {
+			int j = skb_shinfo(skb)->nr_frags;
+			unsigned int copy;
+
+			if (!sglen) {
+				sg = sg_next(sg);
+				sgpg = sg_page(sg);
+				sgoffset = 0;
+				sglen = sg->length;
+				++i;
+			}
+			copy = min(sglen, datalen);
+			if (j && skb_can_coalesce(skb, j, sgpg,
+						  sg->offset + sgoffset)) {
+				skb_shinfo(skb)->frags[j - 1].size += copy;
+			} else {
+				get_page(sgpg);
+				skb_fill_page_desc(skb, j, sgpg,
+						   sg->offset + sgoffset, copy);
+			}
+			sgoffset += copy;
+			sglen -= copy;
+			datalen -= copy;
+		} while (datalen);
+	} else {
+		pg = virt_to_page(task->data);
+
+		while (datalen) {
+			i = skb_shinfo(skb)->nr_frags;
+			frag = &skb_shinfo(skb)->frags[i];
+
+			get_page(pg);
+			frag->page = pg;
+			frag->page_offset = 0;
+			frag->size = min((unsigned int)PAGE_SIZE, datalen);
+
+			skb_shinfo(skb)->nr_frags++;
+			datalen -= frag->size;
+			pg++;
+		}
+	}
+
+	if (padlen) {
+		i = skb_shinfo(skb)->nr_frags;
+		frag = &skb_shinfo(skb)->frags[i];
+		frag->page = pad_page;
+		frag->page_offset = 0;
+		frag->size = padlen;
+		skb_shinfo(skb)->nr_frags++;
+	}
+
+	datalen = count + padlen;
+	skb->data_len += datalen;
+	skb->truesize += datalen;
+	skb->len += datalen;
+	return 0;
+}
+
+int cxgb3i_conn_xmit_pdu(struct iscsi_task *task)
+{
+	struct iscsi_tcp_task *tcp_task = task->dd_data;
+	struct sk_buff *skb = tcp_task->dd_data;
+	struct iscsi_tcp_conn *tcp_conn = task->conn->dd_data;
+	struct cxgb3i_conn *cconn = tcp_conn->dd_data;
+	unsigned int datalen;
+	int err;
+
+	if (!skb)
+		return 0;
+
+	datalen = skb->data_len;
+	tcp_task->dd_data = NULL;
+	err = cxgb3i_c3cn_send_pdus(cconn->cep->c3cn, skb);
+	cxgb3i_tx_debug("task 0x%p, skb 0x%p, len %u/%u, rv %d.\n",
+			task, skb, skb->len, skb->data_len, err);
+	if (err > 0) {
+		int pdulen = err;
+
+		if (task->conn->hdrdgst_en)
+			pdulen += ISCSI_DIGEST_SIZE;
+		if (datalen && task->conn->datadgst_en)
+			pdulen += ISCSI_DIGEST_SIZE;
+
+		task->conn->txdata_octets += pdulen;
+		return 0;
+	}
+
+	if (err < 0 && err != -EAGAIN) {
+		kfree_skb(skb);
+		cxgb3i_tx_debug("itt 0x%x, skb 0x%p, len %u/%u, xmit err %d.\n",
+				task->itt, skb, skb->len, skb->data_len, err);
+		iscsi_conn_printk(KERN_ERR, task->conn, "xmit err %d.\n", err);
+		iscsi_conn_failure(task->conn, ISCSI_ERR_XMIT_FAILED);
+		return err;
+	}
+	/* reset skb to send when we are called again */
+	tcp_task->dd_data = skb;
+	return -EAGAIN;
+}
+
+int cxgb3i_pdu_init(void)
+{
+	pad_page = alloc_page(GFP_KERNEL);
+	if (!pad_page)
+		return -ENOMEM;
+	memset(page_address(pad_page), 0, PAGE_SIZE);
+	return 0;
+}
+
+void cxgb3i_pdu_cleanup(void)
+{
+	if (pad_page) {
+		__free_page(pad_page);
+		pad_page = NULL;
+	}
+}
+
+void cxgb3i_conn_pdu_ready(struct s3_conn *c3cn)
+{
+	struct sk_buff *skb;
+	unsigned int read = 0;
+	struct iscsi_conn *conn = c3cn->user_data;
+	int err = 0;
+
+	cxgb3i_rx_debug("cn 0x%p.\n", c3cn);
+
+	read_lock(&c3cn->callback_lock);
+	if (unlikely(!conn || conn->suspend_rx)) {
+		cxgb3i_rx_debug("conn 0x%p, id %d, suspend_rx %lu!\n",
+				conn, conn ? conn->id : 0xFF,
+				conn ? conn->suspend_rx : 0xFF);
+		read_unlock(&c3cn->callback_lock);
+		return;
+	}
+	skb = skb_peek(&c3cn->receive_queue);
+	while (!err && skb) {
+		__skb_unlink(skb, &c3cn->receive_queue);
+		read += skb_ulp_pdulen(skb);
+		err = cxgb3i_conn_read_pdu_skb(conn, skb);
+		__kfree_skb(skb);
+		skb = skb_peek(&c3cn->receive_queue);
+	}
+	read_unlock(&c3cn->callback_lock);
+	if (c3cn) {
+		c3cn->copied_seq += read;
+		cxgb3i_c3cn_rx_credits(c3cn, read);
+	}
+	conn->rxdata_octets += read;
+}
+
+void cxgb3i_conn_tx_open(struct s3_conn *c3cn)
+{
+	struct iscsi_conn *conn = c3cn->user_data;
+
+	cxgb3i_tx_debug("cn 0x%p.\n", c3cn);
+	if (conn) {
+		cxgb3i_tx_debug("cn 0x%p, cid %d.\n", c3cn, conn->id);
+		scsi_queue_work(conn->session->host, &conn->xmitwork);
+	}
+}
+
+void cxgb3i_conn_closing(struct s3_conn *c3cn)
+{
+	struct iscsi_conn *conn;
+
+	read_lock(&c3cn->callback_lock);
+	conn = c3cn->user_data;
+	if (conn && c3cn->state != C3CN_STATE_ESTABLISHED)
+		iscsi_conn_failure(conn, ISCSI_ERR_CONN_FAILED);
+	read_unlock(&c3cn->callback_lock);
+}

drivers/scsi/cxgb3i/cxgb3i_pdu.h

+/*
+ * cxgb3i_ulp2.h: Chelsio S3xx iSCSI driver.
+ *
+ * Copyright (c) 2008 Chelsio Communications, Inc.
+ *
+ * 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.
+ *
+ * Written by: Karen Xie (kxie@chelsio.com)
+ */
+
+#ifndef __CXGB3I_ULP2_PDU_H__
+#define __CXGB3I_ULP2_PDU_H__
+
+struct cpl_iscsi_hdr_norss {
+	union opcode_tid ot;
+	u16 pdu_len_ddp;
+	u16 len;
+	u32 seq;
+	u16 urg;
+	u8 rsvd;
+	u8 status;
+};
+
+struct cpl_rx_data_ddp_norss {
+	union opcode_tid ot;
+	u16 urg;
+	u16 len;
+	u32 seq;
+	u32 nxt_seq;
+	u32 ulp_crc;
+	u32 ddp_status;
+};
+
+#define RX_DDP_STATUS_IPP_SHIFT		27	/* invalid pagepod */
+#define RX_DDP_STATUS_TID_SHIFT		26	/* tid mismatch */
+#define RX_DDP_STATUS_COLOR_SHIFT	25	/* color mismatch */
+#define RX_DDP_STATUS_OFFSET_SHIFT	24	/* offset mismatch */
+#define RX_DDP_STATUS_ULIMIT_SHIFT	23	/* ulimit error */
+#define RX_DDP_STATUS_TAG_SHIFT		22	/* tag mismatch */
+#define RX_DDP_STATUS_DCRC_SHIFT	21	/* dcrc error */
+#define RX_DDP_STATUS_HCRC_SHIFT	20	/* hcrc error */
+#define RX_DDP_STATUS_PAD_SHIFT		19	/* pad error */
+#define RX_DDP_STATUS_PPP_SHIFT		18	/* pagepod parity error */
+#define RX_DDP_STATUS_LLIMIT_SHIFT	17	/* llimit error */
+#define RX_DDP_STATUS_DDP_SHIFT		16	/* ddp'able */
+#define RX_DDP_STATUS_PMM_SHIFT		15	/* pagepod mismatch */
+
+#define ULP2_FLAG_DATA_READY		0x1
+#define ULP2_FLAG_DATA_DDPED		0x2
+#define ULP2_FLAG_HCRC_ERROR		0x10
+#define ULP2_FLAG_DCRC_ERROR		0x20
+#define ULP2_FLAG_PAD_ERROR		0x40
+
+void cxgb3i_conn_closing(struct s3_conn *);
+void cxgb3i_conn_pdu_ready(struct s3_conn *c3cn);
+void cxgb3i_conn_tx_open(struct s3_conn *c3cn);
+#endif