[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: Karen Xie <kxie@chelsio.com>
Signed-off-by: James Bottomley <James.Bottomley@HansenPartnership.com>

1 files changed, 951 insertions, 0 deletions

diff --git a/drivers/scsi/cxgb3i/cxgb3i_iscsi.c b/drivers/scsi/cxgb3i/cxgb3i_iscsi.c
new file mode 100644
index 000000000000..d83464b9b3f9
--- /dev/null
+++ b/drivers/scsi/cxgb3i/cxgb3i_iscsi.c
@@ -0,0 +1,951 @@
+/* cxgb3i_iscsi.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/inet.h>
+#include <linux/crypto.h>
+#include <net/tcp.h>
+#include <scsi/scsi_cmnd.h>
+#include <scsi/scsi_device.h>
+#include <scsi/scsi_eh.h>
+#include <scsi/scsi_host.h>
+#include <scsi/scsi.h>
+#include <scsi/iscsi_proto.h>
+#include <scsi/libiscsi.h>
+#include <scsi/scsi_transport_iscsi.h>
+
+#include "cxgb3i.h"
+#include "cxgb3i_pdu.h"
+
+#ifdef __DEBUG_CXGB3I_TAG__
+#define cxgb3i_tag_debug        cxgb3i_log_debug
+#else
+#define cxgb3i_tag_debug(fmt...)
+#endif
+
+#ifdef __DEBUG_CXGB3I_API__
+#define cxgb3i_api_debug        cxgb3i_log_debug
+#else
+#define cxgb3i_api_debug(fmt...)
+#endif
+
+/*
+ * align pdu size to multiple of 512 for better performance
+ */
+#define align_pdu_size(n) do { n = (n) & (~511); } while (0)
+
+static struct scsi_transport_template *cxgb3i_scsi_transport;
+static struct scsi_host_template cxgb3i_host_template;
+static struct iscsi_transport cxgb3i_iscsi_transport;
+static unsigned char sw_tag_idx_bits;
+static unsigned char sw_tag_age_bits;
+
+static LIST_HEAD(cxgb3i_snic_list);
+static DEFINE_RWLOCK(cxgb3i_snic_rwlock);
+
+/**
+ * cxgb3i_adapter_add - init a s3 adapter structure and any h/w settings
+ * @t3dev: t3cdev adapter
+ * return the resulting cxgb3i_adapter struct
+ */
+struct cxgb3i_adapter *cxgb3i_adapter_add(struct t3cdev *t3dev)
+{
+        struct cxgb3i_adapter *snic;
+        struct adapter *adapter = tdev2adap(t3dev);
+        int i;
+
+        snic = kzalloc(sizeof(*snic), GFP_KERNEL);
+        if (!snic) {
+                cxgb3i_api_debug("cxgb3 %s, OOM.\n", t3dev->name);
+                return NULL;
+        }
+        spin_lock_init(&snic->lock);
+
+        snic->tdev = t3dev;
+        snic->pdev = adapter->pdev;
+        snic->tag_format.sw_bits = sw_tag_idx_bits + sw_tag_age_bits;
+
+        if (cxgb3i_adapter_ddp_init(t3dev, &snic->tag_format,
+                                    &snic->tx_max_size,
+                                    &snic->rx_max_size) < 0)
+                goto free_snic;
+
+        for_each_port(adapter, i) {
+                snic->hba[i] = cxgb3i_hba_host_add(snic, adapter->port[i]);
+                if (!snic->hba[i])
+                        goto ulp_cleanup;
+        }
+        snic->hba_cnt = adapter->params.nports;
+
+        /* add to the list */
+        write_lock(&cxgb3i_snic_rwlock);
+        list_add_tail(&snic->list_head, &cxgb3i_snic_list);
+        write_unlock(&cxgb3i_snic_rwlock);
+
+        return snic;
+
+ulp_cleanup:
+        cxgb3i_adapter_ddp_cleanup(t3dev);
+free_snic:
+        kfree(snic);
+        return NULL;
+}
+
+/**
+ * cxgb3i_adapter_remove - release all the resources held and cleanup any
+ *      h/w settings
+ * @t3dev: t3cdev adapter
+ */
+void cxgb3i_adapter_remove(struct t3cdev *t3dev)
+{
+        int i;
+        struct cxgb3i_adapter *snic;
+
+        /* remove from the list */
+        write_lock(&cxgb3i_snic_rwlock);
+        list_for_each_entry(snic, &cxgb3i_snic_list, list_head) {
+                if (snic->tdev == t3dev) {
+                        list_del(&snic->list_head);
+                        break;
+                }
+        }
+        write_unlock(&cxgb3i_snic_rwlock);
+
+        if (snic) {
+                for (i = 0; i < snic->hba_cnt; i++) {
+                        if (snic->hba[i]) {
+                                cxgb3i_hba_host_remove(snic->hba[i]);
+                                snic->hba[i] = NULL;
+                        }
+                }
+
+                /* release ddp resources */
+                cxgb3i_adapter_ddp_cleanup(snic->tdev);
+                kfree(snic);
+        }
+}
+
+/**
+ * cxgb3i_hba_find_by_netdev - find the cxgb3i_hba structure with a given
+ *      net_device
+ * @t3dev: t3cdev adapter
+ */
+struct cxgb3i_hba *cxgb3i_hba_find_by_netdev(struct net_device *ndev)
+{
+        struct cxgb3i_adapter *snic;
+        int i;
+
+        read_lock(&cxgb3i_snic_rwlock);
+        list_for_each_entry(snic, &cxgb3i_snic_list, list_head) {
+                for (i = 0; i < snic->hba_cnt; i++) {
+                        if (snic->hba[i]->ndev == ndev) {
+                                read_unlock(&cxgb3i_snic_rwlock);
+                                return snic->hba[i];
+                        }
+                }
+        }
+        read_unlock(&cxgb3i_snic_rwlock);
+        return NULL;
+}
+
+/**
+ * cxgb3i_hba_host_add - register a new host with scsi/iscsi
+ * @snic: the cxgb3i adapter
+ * @ndev: associated net_device
+ */
+struct cxgb3i_hba *cxgb3i_hba_host_add(struct cxgb3i_adapter *snic,
+                                       struct net_device *ndev)
+{
+        struct cxgb3i_hba *hba;
+        struct Scsi_Host *shost;
+        int err;
+
+        shost = iscsi_host_alloc(&cxgb3i_host_template,
+                                 sizeof(struct cxgb3i_hba),
+                                 CXGB3I_SCSI_QDEPTH_DFLT);
+        if (!shost) {
+                cxgb3i_log_info("iscsi_host_alloc failed.\n");
+                return NULL;
+        }
+
+        shost->transportt = cxgb3i_scsi_transport;
+        shost->max_lun = CXGB3I_MAX_LUN;
+        shost->max_id = CXGB3I_MAX_TARGET;
+        shost->max_channel = 0;
+        shost->max_cmd_len = 16;
+
+        hba = iscsi_host_priv(shost);
+        hba->snic = snic;
+        hba->ndev = ndev;
+        hba->shost = shost;
+
+        pci_dev_get(snic->pdev);
+        err = iscsi_host_add(shost, &snic->pdev->dev);
+        if (err) {
+                cxgb3i_log_info("iscsi_host_add failed.\n");
+                goto pci_dev_put;
+        }
+
+        cxgb3i_api_debug("shost 0x%p, hba 0x%p, no %u.\n",
+                         shost, hba, shost->host_no);
+
+        return hba;
+
+pci_dev_put:
+        pci_dev_put(snic->pdev);
+        scsi_host_put(shost);
+        return NULL;
+}
+
+/**
+ * cxgb3i_hba_host_remove - de-register the host with scsi/iscsi
+ * @hba: the cxgb3i hba
+ */
+void cxgb3i_hba_host_remove(struct cxgb3i_hba *hba)
+{
+        cxgb3i_api_debug("shost 0x%p, hba 0x%p, no %u.\n",
+                         hba->shost, hba, hba->shost->host_no);
+        iscsi_host_remove(hba->shost);
+        pci_dev_put(hba->snic->pdev);
+        iscsi_host_free(hba->shost);
+}
+
+/**
+ * cxgb3i_ep_connect - establish TCP connection to target portal
+ * @dst_addr:           target IP address
+ * @non_blocking:       blocking or non-blocking call
+ *
+ * Initiates a TCP/IP connection to the dst_addr
+ */
+static struct iscsi_endpoint *cxgb3i_ep_connect(struct sockaddr *dst_addr,
+                                                int non_blocking)
+{
+        struct iscsi_endpoint *ep;
+        struct cxgb3i_endpoint *cep;
+        struct cxgb3i_hba *hba;
+        struct s3_conn *c3cn = NULL;
+        int err = 0;
+
+        c3cn = cxgb3i_c3cn_create();
+        if (!c3cn) {
+                cxgb3i_log_info("ep connect OOM.\n");
+                err = -ENOMEM;
+                goto release_conn;
+        }
+
+        err = cxgb3i_c3cn_connect(c3cn, (struct sockaddr_in *)dst_addr);
+        if (err < 0) {
+                cxgb3i_log_info("ep connect failed.\n");
+                goto release_conn;
+        }
+        hba = cxgb3i_hba_find_by_netdev(c3cn->dst_cache->dev);
+        if (!hba) {
+                err = -ENOSPC;
+                cxgb3i_log_info("NOT going through cxgbi device.\n");
+                goto release_conn;
+        }
+        if (c3cn_is_closing(c3cn)) {
+                err = -ENOSPC;
+                cxgb3i_log_info("ep connect unable to connect.\n");
+                goto release_conn;
+        }
+
+        ep = iscsi_create_endpoint(sizeof(*cep));
+        if (!ep) {
+                err = -ENOMEM;
+                cxgb3i_log_info("iscsi alloc ep, OOM.\n");
+                goto release_conn;
+        }
+        cep = ep->dd_data;
+        cep->c3cn = c3cn;
+        cep->hba = hba;
+
+        cxgb3i_api_debug("ep 0x%p, 0x%p, c3cn 0x%p, hba 0x%p.\n",
+                          ep, cep, c3cn, hba);
+        return ep;
+
+release_conn:
+        cxgb3i_api_debug("conn 0x%p failed, release.\n", c3cn);
+        if (c3cn)
+                cxgb3i_c3cn_release(c3cn);
+        return ERR_PTR(err);
+}
+
+/**
+ * cxgb3i_ep_poll - polls for TCP connection establishement
+ * @ep:         TCP connection (endpoint) handle
+ * @timeout_ms: timeout value in milli secs
+ *
+ * polls for TCP connect request to complete
+ */
+static int cxgb3i_ep_poll(struct iscsi_endpoint *ep, int timeout_ms)
+{
+        struct cxgb3i_endpoint *cep = ep->dd_data;
+        struct s3_conn *c3cn = cep->c3cn;
+
+        if (!c3cn_is_established(c3cn))
+                return 0;
+        cxgb3i_api_debug("ep 0x%p, c3cn 0x%p established.\n", ep, c3cn);
+        return 1;
+}
+
+/**
+ * cxgb3i_ep_disconnect - teardown TCP connection
+ * @ep:         TCP connection (endpoint) handle
+ *
+ * teardown TCP connection
+ */
+static void cxgb3i_ep_disconnect(struct iscsi_endpoint *ep)
+{
+        struct cxgb3i_endpoint *cep = ep->dd_data;
+        struct cxgb3i_conn *cconn = cep->cconn;
+
+        cxgb3i_api_debug("ep 0x%p, cep 0x%p.\n", ep, cep);
+
+        if (cconn && cconn->conn) {
+                /*
+                 * stop the xmit path so the xmit_pdu function is
+                 * not being called
+                 */
+                iscsi_suspend_tx(cconn->conn);
+
+                write_lock_bh(&cep->c3cn->callback_lock);
+                cep->c3cn->user_data = NULL;
+                cconn->cep = NULL;
+                write_unlock_bh(&cep->c3cn->callback_lock);
+        }
+
+        cxgb3i_api_debug("ep 0x%p, cep 0x%p, release c3cn 0x%p.\n",
+                         ep, cep, cep->c3cn);
+        cxgb3i_c3cn_release(cep->c3cn);
+        iscsi_destroy_endpoint(ep);
+}
+
+/**
+ * cxgb3i_session_create - create a new iscsi session
+ * @cmds_max:           max # of commands
+ * @qdepth:             scsi queue depth
+ * @initial_cmdsn:      initial iscsi CMDSN for this session
+ * @host_no:            pointer to return host no
+ *
+ * Creates a new iSCSI session
+ */
+static struct iscsi_cls_session *
+cxgb3i_session_create(struct iscsi_endpoint *ep, u16 cmds_max, u16 qdepth,
+                      u32 initial_cmdsn, u32 *host_no)
+{
+        struct cxgb3i_endpoint *cep;
+        struct cxgb3i_hba *hba;
+        struct Scsi_Host *shost;
+        struct iscsi_cls_session *cls_session;
+        struct iscsi_session *session;
+
+        if (!ep) {
+                cxgb3i_log_error("%s, missing endpoint.\n", __func__);
+                return NULL;
+        }
+
+        cep = ep->dd_data;
+        hba = cep->hba;
+        shost = hba->shost;
+        cxgb3i_api_debug("ep 0x%p, cep 0x%p, hba 0x%p.\n", ep, cep, hba);
+        BUG_ON(hba != iscsi_host_priv(shost));
+
+        *host_no = shost->host_no;
+
+        cls_session = iscsi_session_setup(&cxgb3i_iscsi_transport, shost,
+                                          cmds_max,
+                                          sizeof(struct iscsi_tcp_task),
+                                          initial_cmdsn, ISCSI_MAX_TARGET);
+        if (!cls_session)
+                return NULL;
+        session = cls_session->dd_data;
+        if (iscsi_tcp_r2tpool_alloc(session))
+                goto remove_session;
+
+        return cls_session;
+
+remove_session:
+        iscsi_session_teardown(cls_session);
+        return NULL;
+}
+
+/**
+ * cxgb3i_session_destroy - destroys iscsi session
+ * @cls_session:        pointer to iscsi cls session
+ *
+ * Destroys an iSCSI session instance and releases its all resources held
+ */
+static void cxgb3i_session_destroy(struct iscsi_cls_session *cls_session)
+{
+        cxgb3i_api_debug("sess 0x%p.\n", cls_session);
+        iscsi_tcp_r2tpool_free(cls_session->dd_data);
+        iscsi_session_teardown(cls_session);
+}
+
+/**
+ * cxgb3i_conn_max_xmit_dlength -- check the max. xmit pdu segment size,
+ * reduce it to be within the hardware limit if needed
+ * @conn: iscsi connection
+ */
+static inline int cxgb3i_conn_max_xmit_dlength(struct iscsi_conn *conn)
+
+{
+        struct iscsi_tcp_conn *tcp_conn = conn->dd_data;
+        struct cxgb3i_conn *cconn = tcp_conn->dd_data;
+        unsigned int max = min_t(unsigned int, ULP2_MAX_PDU_PAYLOAD,
+                                 cconn->hba->snic->tx_max_size -
+                                 ISCSI_PDU_NONPAYLOAD_MAX);
+
+        if (conn->max_xmit_dlength)
+                conn->max_xmit_dlength = min_t(unsigned int,
+                                                conn->max_xmit_dlength, max);
+        else
+                conn->max_xmit_dlength = max;
+        align_pdu_size(conn->max_xmit_dlength);
+        cxgb3i_log_info("conn 0x%p, max xmit %u.\n",
+                         conn, conn->max_xmit_dlength);
+        return 0;
+}
+
+/**
+ * cxgb3i_conn_max_recv_dlength -- check the max. recv pdu segment size against
+ * the hardware limit
+ * @conn: iscsi connection
+ * return 0 if the value is valid, < 0 otherwise.
+ */
+static inline int cxgb3i_conn_max_recv_dlength(struct iscsi_conn *conn)
+{
+        struct iscsi_tcp_conn *tcp_conn = conn->dd_data;
+        struct cxgb3i_conn *cconn = tcp_conn->dd_data;
+        unsigned int max = min_t(unsigned int, ULP2_MAX_PDU_PAYLOAD,
+                                 cconn->hba->snic->rx_max_size -
+                                 ISCSI_PDU_NONPAYLOAD_MAX);
+
+        align_pdu_size(max);
+        if (conn->max_recv_dlength) {
+                if (conn->max_recv_dlength > max) {
+                        cxgb3i_log_error("MaxRecvDataSegmentLength %u too big."
+                                         " Need to be <= %u.\n",
+                                         conn->max_recv_dlength, max);
+                        return -EINVAL;
+                }
+                conn->max_recv_dlength = min_t(unsigned int,
+                                                conn->max_recv_dlength, max);
+                align_pdu_size(conn->max_recv_dlength);
+        } else
+                conn->max_recv_dlength = max;
+        cxgb3i_api_debug("conn 0x%p, max recv %u.\n",
+                         conn, conn->max_recv_dlength);
+        return 0;
+}
+
+/**
+ * cxgb3i_conn_create - create iscsi connection instance
+ * @cls_session:        pointer to iscsi cls session
+ * @cid:                iscsi cid
+ *
+ * Creates a new iSCSI connection instance for a given session
+ */
+static struct iscsi_cls_conn *cxgb3i_conn_create(struct iscsi_cls_session
+                                                 *cls_session, u32 cid)
+{
+        struct iscsi_cls_conn *cls_conn;
+        struct iscsi_conn *conn;
+        struct iscsi_tcp_conn *tcp_conn;
+        struct cxgb3i_conn *cconn;
+
+        cxgb3i_api_debug("sess 0x%p, cid %u.\n", cls_session, cid);
+
+        cls_conn = iscsi_tcp_conn_setup(cls_session, sizeof(*cconn), cid);
+        if (!cls_conn)
+                return NULL;
+        conn = cls_conn->dd_data;
+        tcp_conn = conn->dd_data;
+        cconn = tcp_conn->dd_data;
+
+        cconn->conn = conn;
+        return cls_conn;
+}
+
+/**
+ * cxgb3i_conn_bind - binds iscsi sess, conn and endpoint together
+ * @cls_session:        pointer to iscsi cls session
+ * @cls_conn:           pointer to iscsi cls conn
+ * @transport_eph:      64-bit EP handle
+ * @is_leading:         leading connection on this session?
+ *
+ * Binds together an iSCSI session, an iSCSI connection and a
+ *      TCP connection. This routine returns error code if the TCP
+ *      connection does not belong on the device iSCSI sess/conn is bound
+ */
+
+static int cxgb3i_conn_bind(struct iscsi_cls_session *cls_session,
+                            struct iscsi_cls_conn *cls_conn,
+                            u64 transport_eph, int is_leading)
+{
+        struct iscsi_conn *conn = cls_conn->dd_data;
+        struct iscsi_tcp_conn *tcp_conn = conn->dd_data;
+        struct cxgb3i_conn *cconn = tcp_conn->dd_data;
+        struct cxgb3i_adapter *snic;
+        struct iscsi_endpoint *ep;
+        struct cxgb3i_endpoint *cep;
+        struct s3_conn *c3cn;
+        int err;
+
+        ep = iscsi_lookup_endpoint(transport_eph);
+        if (!ep)
+                return -EINVAL;
+
+        /* setup ddp pagesize */
+        cep = ep->dd_data;
+        c3cn = cep->c3cn;
+        snic = cep->hba->snic;
+        err = cxgb3i_setup_conn_host_pagesize(snic->tdev, c3cn->tid, 0);
+        if (err < 0)
+                return err;
+
+        cxgb3i_api_debug("ep 0x%p, cls sess 0x%p, cls conn 0x%p.\n",
+                         ep, cls_session, cls_conn);
+
+        err = iscsi_conn_bind(cls_session, cls_conn, is_leading);
+        if (err)
+                return -EINVAL;
+
+        /* calculate the tag idx bits needed for this conn based on cmds_max */
+        cconn->task_idx_bits = (__ilog2_u32(conn->session->cmds_max - 1)) + 1;
+        cxgb3i_api_debug("session cmds_max 0x%x, bits %u.\n",
+                         conn->session->cmds_max, cconn->task_idx_bits);
+
+        read_lock(&c3cn->callback_lock);
+        c3cn->user_data = conn;
+        cconn->hba = cep->hba;
+        cconn->cep = cep;
+        cep->cconn = cconn;
+        read_unlock(&c3cn->callback_lock);
+
+        cxgb3i_conn_max_xmit_dlength(conn);
+        cxgb3i_conn_max_recv_dlength(conn);
+
+        spin_lock_bh(&conn->session->lock);
+        sprintf(conn->portal_address, NIPQUAD_FMT,
+                NIPQUAD(c3cn->daddr.sin_addr.s_addr));
+        conn->portal_port = ntohs(c3cn->daddr.sin_port);
+        spin_unlock_bh(&conn->session->lock);
+
+        /* init recv engine */
+        iscsi_tcp_hdr_recv_prep(tcp_conn);
+
+        return 0;
+}
+
+/**
+ * cxgb3i_conn_get_param - return iscsi connection parameter to caller
+ * @cls_conn:   pointer to iscsi cls conn
+ * @param:      parameter type identifier
+ * @buf:        buffer pointer
+ *
+ * returns iSCSI connection parameters
+ */
+static int cxgb3i_conn_get_param(struct iscsi_cls_conn *cls_conn,
+                                 enum iscsi_param param, char *buf)
+{
+        struct iscsi_conn *conn = cls_conn->dd_data;
+        int len;
+
+        cxgb3i_api_debug("cls_conn 0x%p, param %d.\n", cls_conn, param);
+
+        switch (param) {
+        case ISCSI_PARAM_CONN_PORT:
+                spin_lock_bh(&conn->session->lock);
+                len = sprintf(buf, "%hu\n", conn->portal_port);
+                spin_unlock_bh(&conn->session->lock);
+                break;
+        case ISCSI_PARAM_CONN_ADDRESS:
+                spin_lock_bh(&conn->session->lock);
+                len = sprintf(buf, "%s\n", conn->portal_address);
+                spin_unlock_bh(&conn->session->lock);
+                break;
+        default:
+                return iscsi_conn_get_param(cls_conn, param, buf);
+        }
+
+        return len;
+}
+
+/**
+ * cxgb3i_conn_set_param - set iscsi connection parameter
+ * @cls_conn:   pointer to iscsi cls conn
+ * @param:      parameter type identifier
+ * @buf:        buffer pointer
+ * @buflen:     buffer length
+ *
+ * set iSCSI connection parameters
+ */
+static int cxgb3i_conn_set_param(struct iscsi_cls_conn *cls_conn,
+                                 enum iscsi_param param, char *buf, int buflen)
+{
+        struct iscsi_conn *conn = cls_conn->dd_data;
+        struct iscsi_session *session = conn->session;
+        struct iscsi_tcp_conn *tcp_conn = conn->dd_data;
+        struct cxgb3i_conn *cconn = tcp_conn->dd_data;
+        struct cxgb3i_adapter *snic = cconn->hba->snic;
+        struct s3_conn *c3cn = cconn->cep->c3cn;
+        int value, err = 0;
+
+        switch (param) {
+        case ISCSI_PARAM_HDRDGST_EN:
+                err = iscsi_set_param(cls_conn, param, buf, buflen);
+                if (!err && conn->hdrdgst_en)
+                        err = cxgb3i_setup_conn_digest(snic->tdev, c3cn->tid,
+                                                        conn->hdrdgst_en,
+                                                        conn->datadgst_en, 0);
+                break;
+        case ISCSI_PARAM_DATADGST_EN:
+                err = iscsi_set_param(cls_conn, param, buf, buflen);
+                if (!err && conn->datadgst_en)
+                        err = cxgb3i_setup_conn_digest(snic->tdev, c3cn->tid,
+                                                        conn->hdrdgst_en,
+                                                        conn->datadgst_en, 0);
+                break;
+        case ISCSI_PARAM_MAX_R2T:
+                sscanf(buf, "%d", &value);
+                if (value <= 0 || !is_power_of_2(value))
+                        return -EINVAL;
+                if (session->max_r2t == value)
+                        break;
+                iscsi_tcp_r2tpool_free(session);
+                err = iscsi_set_param(cls_conn, param, buf, buflen);
+                if (!err && iscsi_tcp_r2tpool_alloc(session))
+                        return -ENOMEM;
+        case ISCSI_PARAM_MAX_RECV_DLENGTH:
+                err = iscsi_set_param(cls_conn, param, buf, buflen);
+                if (!err)
+                        err = cxgb3i_conn_max_recv_dlength(conn);
+                break;
+        case ISCSI_PARAM_MAX_XMIT_DLENGTH:
+                err = iscsi_set_param(cls_conn, param, buf, buflen);
+                if (!err)
+                        err = cxgb3i_conn_max_xmit_dlength(conn);
+                break;
+        default:
+                return iscsi_set_param(cls_conn, param, buf, buflen);
+        }
+        return err;
+}
+
+/**
+ * cxgb3i_host_set_param - configure host (adapter) related parameters
+ * @shost:      scsi host pointer
+ * @param:      parameter type identifier
+ * @buf:        buffer pointer
+ */
+static int cxgb3i_host_set_param(struct Scsi_Host *shost,
+                                 enum iscsi_host_param param,
+                                 char *buf, int buflen)
+{
+        struct cxgb3i_hba *hba = iscsi_host_priv(shost);
+
+        cxgb3i_api_debug("param %d, buf %s.\n", param, buf);
+
+        switch (param) {
+        case ISCSI_HOST_PARAM_IPADDRESS:
+        {
+                __be32 addr = in_aton(buf);
+                cxgb3i_set_private_ipv4addr(hba->ndev, addr);
+                return 0;
+        }
+        case ISCSI_HOST_PARAM_HWADDRESS:
+        case ISCSI_HOST_PARAM_NETDEV_NAME:
+                /* ignore */
+                return 0;
+        default:
+                return iscsi_host_set_param(shost, param, buf, buflen);
+        }
+}
+
+/**
+ * cxgb3i_host_get_param - returns host (adapter) related parameters
+ * @shost:      scsi host pointer
+ * @param:      parameter type identifier
+ * @buf:        buffer pointer
+ */
+static int cxgb3i_host_get_param(struct Scsi_Host *shost,
+                                 enum iscsi_host_param param, char *buf)
+{
+        struct cxgb3i_hba *hba = iscsi_host_priv(shost);
+        int len = 0;
+
+        cxgb3i_api_debug("hba %s, param %d.\n", hba->ndev->name, param);
+
+        switch (param) {
+        case ISCSI_HOST_PARAM_HWADDRESS:
+                len = sysfs_format_mac(buf, hba->ndev->dev_addr, 6);
+                break;
+        case ISCSI_HOST_PARAM_NETDEV_NAME:
+                len = sprintf(buf, "%s\n", hba->ndev->name);
+                break;
+        case ISCSI_HOST_PARAM_IPADDRESS:
+        {
+                __be32 addr;
+
+                addr = cxgb3i_get_private_ipv4addr(hba->ndev);
+                len = sprintf(buf, NIPQUAD_FMT, NIPQUAD(addr));
+                break;
+        }
+        default:
+                return iscsi_host_get_param(shost, param, buf);
+        }
+        return len;
+}
+
+/**
+ * cxgb3i_conn_get_stats - returns iSCSI stats
+ * @cls_conn:   pointer to iscsi cls conn
+ * @stats:      pointer to iscsi statistic struct
+ */
+static void cxgb3i_conn_get_stats(struct iscsi_cls_conn *cls_conn,
+                                  struct iscsi_stats *stats)
+{
+        struct iscsi_conn *conn = cls_conn->dd_data;
+
+        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->digest_err = 0;
+        stats->timeout_err = 0;
+        stats->custom_length = 1;
+        strcpy(stats->custom[0].desc, "eh_abort_cnt");
+        stats->custom[0].value = conn->eh_abort_cnt;
+}
+
+/**
+ * cxgb3i_parse_itt - get the idx and age bits from a given tag
+ * @conn:       iscsi connection
+ * @itt:        itt tag
+ * @idx:        task index, filled in by this function
+ * @age:        session age, filled in by this function
+ */
+static void cxgb3i_parse_itt(struct iscsi_conn *conn, itt_t itt,
+                             int *idx, int *age)
+{
+        struct iscsi_tcp_conn *tcp_conn = conn->dd_data;
+        struct cxgb3i_conn *cconn = tcp_conn->dd_data;
+        struct cxgb3i_adapter *snic = cconn->hba->snic;
+        u32 tag = ntohl((__force u32) itt);
+        u32 sw_bits;
+
+        sw_bits = cxgb3i_tag_nonrsvd_bits(&snic->tag_format, tag);
+        if (idx)
+                *idx = sw_bits & ((1 << cconn->task_idx_bits) - 1);
+        if (age)
+                *age = (sw_bits >> cconn->task_idx_bits) & ISCSI_AGE_MASK;
+
+        cxgb3i_tag_debug("parse tag 0x%x/0x%x, sw 0x%x, itt 0x%x, age 0x%x.\n",
+                         tag, itt, sw_bits, idx ? *idx : 0xFFFFF,
+                         age ? *age : 0xFF);
+}
+
+/**
+ * cxgb3i_reserve_itt - generate tag for a give task
+ * Try to set up ddp for a scsi read task.
+ * @task: iscsi task
+ * @hdr_itt: tag, filled in by this function
+ */
+int cxgb3i_reserve_itt(struct iscsi_task *task, itt_t *hdr_itt)
+{
+        struct scsi_cmnd *sc = task->sc;
+        struct iscsi_conn *conn = task->conn;
+        struct iscsi_session *sess = conn->session;
+        struct iscsi_tcp_conn *tcp_conn = conn->dd_data;
+        struct cxgb3i_conn *cconn = tcp_conn->dd_data;
+        struct cxgb3i_adapter *snic = cconn->hba->snic;
+        struct cxgb3i_tag_format *tformat = &snic->tag_format;
+        u32 sw_tag = (sess->age << cconn->task_idx_bits) | task->itt;
+        u32 tag;
+        int err = -EINVAL;
+
+        if (sc &&
+            (scsi_bidi_cmnd(sc) || sc->sc_data_direction == DMA_FROM_DEVICE) &&
+            cxgb3i_sw_tag_usable(tformat, sw_tag)) {
+                struct s3_conn *c3cn = cconn->cep->c3cn;
+                struct cxgb3i_gather_list *gl;
+
+                gl = cxgb3i_ddp_make_gl(scsi_in(sc)->length,
+                                        scsi_in(sc)->table.sgl,
+                                        scsi_in(sc)->table.nents,
+                                        snic->pdev,
+                                        GFP_ATOMIC);
+                if (gl) {
+                        tag = sw_tag;
+                        err = cxgb3i_ddp_tag_reserve(snic->tdev, c3cn->tid,
+                                                     tformat, &tag,
+                                                     gl, GFP_ATOMIC);
+                        if (err < 0)
+                                cxgb3i_ddp_release_gl(gl, snic->pdev);
+                }
+        }
+
+        if (err < 0)
+                tag = cxgb3i_set_non_ddp_tag(tformat, sw_tag);
+        /* the itt need to sent in big-endian order */
+        *hdr_itt = (__force itt_t)htonl(tag);
+
+        cxgb3i_tag_debug("new tag 0x%x/0x%x (itt 0x%x, age 0x%x).\n",
+                         tag, *hdr_itt, task->itt, sess->age);
+        return 0;
+}
+
+/**
+ * cxgb3i_release_itt - release the tag for a given task
+ * if the tag is a ddp tag, release the ddp setup
+ * @task:       iscsi task
+ * @hdr_itt:    tag
+ */
+void cxgb3i_release_itt(struct iscsi_task *task, itt_t hdr_itt)
+{
+        struct scsi_cmnd *sc = task->sc;
+        struct iscsi_tcp_conn *tcp_conn = task->conn->dd_data;
+        struct cxgb3i_conn *cconn = tcp_conn->dd_data;
+        struct cxgb3i_adapter *snic = cconn->hba->snic;
+        struct cxgb3i_tag_format *tformat = &snic->tag_format;
+        u32 tag = ntohl((__force u32)hdr_itt);
+
+        cxgb3i_tag_debug("release tag 0x%x.\n", tag);
+
+        if (sc &&
+            (scsi_bidi_cmnd(sc) || sc->sc_data_direction == DMA_FROM_DEVICE) &&
+            cxgb3i_is_ddp_tag(tformat, tag))
+                cxgb3i_ddp_tag_release(snic->tdev, tag);
+}
+
+/**
+ * cxgb3i_host_template -- Scsi_Host_Template structure
+ *      used when registering with the scsi mid layer
+ */
+static struct scsi_host_template cxgb3i_host_template = {
+        .module                 = THIS_MODULE,
+        .name                   = "Chelsio S3xx iSCSI Initiator",
+        .proc_name              = "cxgb3i",
+        .queuecommand           = iscsi_queuecommand,
+        .change_queue_depth     = iscsi_change_queue_depth,
+        .can_queue              = 128 * (ISCSI_DEF_XMIT_CMDS_MAX - 1),
+        .sg_tablesize           = SG_ALL,
+        .max_sectors            = 0xFFFF,
+        .cmd_per_lun            = ISCSI_DEF_CMD_PER_LUN,
+        .eh_abort_handler       = iscsi_eh_abort,
+        .eh_device_reset_handler = iscsi_eh_device_reset,
+        .eh_target_reset_handler = iscsi_eh_target_reset,
+        .use_clustering         = DISABLE_CLUSTERING,
+        .this_id                = -1,
+};
+
+static struct iscsi_transport cxgb3i_iscsi_transport = {
+        .owner                  = THIS_MODULE,
+        .name                   = "cxgb3i",
+        .caps                   = CAP_RECOVERY_L0 | CAP_MULTI_R2T | CAP_HDRDGST
+                                | CAP_DATADGST | CAP_DIGEST_OFFLOAD |
+                                CAP_PADDING_OFFLOAD,
+        .param_mask             = ISCSI_MAX_RECV_DLENGTH |
+                                ISCSI_MAX_XMIT_DLENGTH |
+                                ISCSI_HDRDGST_EN |
+                                ISCSI_DATADGST_EN |
+                                ISCSI_INITIAL_R2T_EN |
+                                ISCSI_MAX_R2T |
+                                ISCSI_IMM_DATA_EN |
+                                ISCSI_FIRST_BURST |
+                                ISCSI_MAX_BURST |
+                                ISCSI_PDU_INORDER_EN |
+                                ISCSI_DATASEQ_INORDER_EN |
+                                ISCSI_ERL |
+                                ISCSI_CONN_PORT |
+                                ISCSI_CONN_ADDRESS |
+                                ISCSI_EXP_STATSN |
+                                ISCSI_PERSISTENT_PORT |
+                                ISCSI_PERSISTENT_ADDRESS |
+                                ISCSI_TARGET_NAME | ISCSI_TPGT |
+                                ISCSI_USERNAME | ISCSI_PASSWORD |
+                                ISCSI_USERNAME_IN | ISCSI_PASSWORD_IN |
+                                ISCSI_FAST_ABORT | ISCSI_ABORT_TMO |
+                                ISCSI_LU_RESET_TMO |
+                                ISCSI_PING_TMO | ISCSI_RECV_TMO |
+                                ISCSI_IFACE_NAME | ISCSI_INITIATOR_NAME,
+        .host_param_mask        = ISCSI_HOST_HWADDRESS | ISCSI_HOST_IPADDRESS |
+                        ISCSI_HOST_INITIATOR_NAME | ISCSI_HOST_NETDEV_NAME,
+        .get_host_param         = cxgb3i_host_get_param,
+        .set_host_param         = cxgb3i_host_set_param,
+        /* session management */
+        .create_session         = cxgb3i_session_create,
+        .destroy_session        = cxgb3i_session_destroy,
+        .get_session_param      = iscsi_session_get_param,
+        /* connection management */
+        .create_conn            = cxgb3i_conn_create,
+        .bind_conn              = cxgb3i_conn_bind,
+        .destroy_conn           = iscsi_tcp_conn_teardown,
+        .start_conn             = iscsi_conn_start,
+        .stop_conn              = iscsi_conn_stop,
+        .get_conn_param         = cxgb3i_conn_get_param,
+        .set_param              = cxgb3i_conn_set_param,
+        .get_stats              = cxgb3i_conn_get_stats,
+        /* pdu xmit req. from user space */
+        .send_pdu               = iscsi_conn_send_pdu,
+        /* task */
+        .init_task              = iscsi_tcp_task_init,
+        .xmit_task              = iscsi_tcp_task_xmit,
+        .cleanup_task           = cxgb3i_conn_cleanup_task,
+
+        /* pdu */
+        .alloc_pdu              = cxgb3i_conn_alloc_pdu,
+        .init_pdu               = cxgb3i_conn_init_pdu,
+        .xmit_pdu               = cxgb3i_conn_xmit_pdu,
+        .parse_pdu_itt          = cxgb3i_parse_itt,
+
+        /* TCP connect/disconnect */
+        .ep_connect             = cxgb3i_ep_connect,
+        .ep_poll                = cxgb3i_ep_poll,
+        .ep_disconnect          = cxgb3i_ep_disconnect,
+        /* Error recovery timeout call */
+        .session_recovery_timedout = iscsi_session_recovery_timedout,
+};
+
+int cxgb3i_iscsi_init(void)
+{
+        sw_tag_idx_bits = (__ilog2_u32(ISCSI_ITT_MASK)) + 1;
+        sw_tag_age_bits = (__ilog2_u32(ISCSI_AGE_MASK)) + 1;
+        cxgb3i_log_info("tag itt 0x%x, %u bits, age 0x%x, %u bits.\n",
+                        ISCSI_ITT_MASK, sw_tag_idx_bits,
+                        ISCSI_AGE_MASK, sw_tag_age_bits);
+
+        cxgb3i_scsi_transport =
+            iscsi_register_transport(&cxgb3i_iscsi_transport);
+        if (!cxgb3i_scsi_transport) {
+                cxgb3i_log_error("Could not register cxgb3i transport.\n");
+                return -ENODEV;
+        }
+        cxgb3i_api_debug("cxgb3i transport 0x%p.\n", cxgb3i_scsi_transport);
+        return 0;
+}
+
+void cxgb3i_iscsi_cleanup(void)
+{
+        if (cxgb3i_scsi_transport) {
+                cxgb3i_api_debug("cxgb3i transport 0x%p.\n",
+                                 cxgb3i_scsi_transport);
+                iscsi_unregister_transport(&cxgb3i_iscsi_transport);
+        }
+}