/*
 * libcxgbi.c: Chelsio common library for T3/T4 iSCSI driver.
 *
 * Copyright (c) 2010 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)
 * Written by: Rakesh Ranjan (rranjan@chelsio.com)
 */

#define pr_fmt(fmt)     KBUILD_MODNAME ":%s: " fmt, __func__

#include <linux/skbuff.h>
#include <linux/crypto.h>
#include <linux/scatterlist.h>
#include <linux/pci.h>
#include <scsi/scsi.h>
#include <scsi/scsi_cmnd.h>
#include <scsi/scsi_host.h>
#include <linux/if_vlan.h>
#include <linux/inet.h>
#include <net/dst.h>
#include <net/route.h>
#include <net/ipv6.h>
#include <net/ip6_route.h>
#include <net/addrconf.h>

#include <linux/inetdevice.h>   /* ip_dev_find */
#include <linux/module.h>
#include <net/tcp.h>

static unsigned int dbg_level;

#include "libcxgbi.h"

#define DRV_MODULE_NAME         "libcxgbi"
#define DRV_MODULE_DESC         "Chelsio iSCSI driver library"
#define DRV_MODULE_VERSION      "0.9.0"
#define DRV_MODULE_RELDATE      "Jun. 2010"

MODULE_AUTHOR("Chelsio Communications, Inc.");
MODULE_DESCRIPTION(DRV_MODULE_DESC);
MODULE_VERSION(DRV_MODULE_VERSION);
MODULE_LICENSE("GPL");

module_param(dbg_level, uint, 0644);
MODULE_PARM_DESC(dbg_level, "libiscsi debug level (default=0)");


/*
 * cxgbi device management
 * maintains a list of the cxgbi devices
 */
static LIST_HEAD(cdev_list);
static DEFINE_MUTEX(cdev_mutex);

static LIST_HEAD(cdev_rcu_list);
static DEFINE_SPINLOCK(cdev_rcu_lock);

int cxgbi_device_portmap_create(struct cxgbi_device *cdev, unsigned int base,
                                unsigned int max_conn)
{
        struct cxgbi_ports_map *pmap = &cdev->pmap;

        pmap->port_csk = cxgbi_alloc_big_mem(max_conn *
                                             sizeof(struct cxgbi_sock *),
                                             GFP_KERNEL);
        if (!pmap->port_csk) {
                pr_warn("cdev 0x%p, portmap OOM %u.\n", cdev, max_conn);
                return -ENOMEM;
        }

        pmap->max_connect = max_conn;
        pmap->sport_base = base;
        spin_lock_init(&pmap->lock);
        return 0;
}
EXPORT_SYMBOL_GPL(cxgbi_device_portmap_create);

void cxgbi_device_portmap_cleanup(struct cxgbi_device *cdev)
{
        struct cxgbi_ports_map *pmap = &cdev->pmap;
        struct cxgbi_sock *csk;
        int i;

        for (i = 0; i < pmap->max_connect; i++) {
                if (pmap->port_csk[i]) {
                        csk = pmap->port_csk[i];
                        pmap->port_csk[i] = NULL;
                        log_debug(1 << CXGBI_DBG_SOCK,
                                "csk 0x%p, cdev 0x%p, offload down.\n",
                                csk, cdev);
                        spin_lock_bh(&csk->lock);
                        cxgbi_sock_set_flag(csk, CTPF_OFFLOAD_DOWN);
                        cxgbi_sock_closed(csk);
                        spin_unlock_bh(&csk->lock);
                        cxgbi_sock_put(csk);
                }
        }
}
EXPORT_SYMBOL_GPL(cxgbi_device_portmap_cleanup);

static inline void cxgbi_device_destroy(struct cxgbi_device *cdev)
{
        log_debug(1 << CXGBI_DBG_DEV,
                "cdev 0x%p, p# %u.\n", cdev, cdev->nports);
        cxgbi_hbas_remove(cdev);
        cxgbi_device_portmap_cleanup(cdev);
        if (cdev->dev_ddp_cleanup)
                cdev->dev_ddp_cleanup(cdev);
        else
                cxgbi_ddp_cleanup(cdev);
        if (cdev->ddp)
                cxgbi_ddp_cleanup(cdev);
        if (cdev->pmap.max_connect)
                cxgbi_free_big_mem(cdev->pmap.port_csk);
        kfree(cdev);
}

struct cxgbi_device *cxgbi_device_register(unsigned int extra,
                                           unsigned int nports)
{
        struct cxgbi_device *cdev;

        cdev = kzalloc(sizeof(*cdev) + extra + nports *
                        (sizeof(struct cxgbi_hba *) +
                         sizeof(struct net_device *)),
                        GFP_KERNEL);
        if (!cdev) {
                pr_warn("nport %d, OOM.\n", nports);
                return NULL;
        }
        cdev->ports = (struct net_device **)(cdev + 1);
        cdev->hbas = (struct cxgbi_hba **)(((char*)cdev->ports) + nports *
                                                sizeof(struct net_device *));
        if (extra)
                cdev->dd_data = ((char *)cdev->hbas) +
                                nports * sizeof(struct cxgbi_hba *);
        spin_lock_init(&cdev->pmap.lock);

        mutex_lock(&cdev_mutex);
        list_add_tail(&cdev->list_head, &cdev_list);
        mutex_unlock(&cdev_mutex);

        spin_lock(&cdev_rcu_lock);
        list_add_tail_rcu(&cdev->rcu_node, &cdev_rcu_list);
        spin_unlock(&cdev_rcu_lock);

        log_debug(1 << CXGBI_DBG_DEV,
                "cdev 0x%p, p# %u.\n", cdev, nports);
        return cdev;
}
EXPORT_SYMBOL_GPL(cxgbi_device_register);

void cxgbi_device_unregister(struct cxgbi_device *cdev)
{
        log_debug(1 << CXGBI_DBG_DEV,
                "cdev 0x%p, p# %u,%s.\n",
                cdev, cdev->nports, cdev->nports ? cdev->ports[0]->name : "");

        mutex_lock(&cdev_mutex);
        list_del(&cdev->list_head);
        mutex_unlock(&cdev_mutex);

        spin_lock(&cdev_rcu_lock);
        list_del_rcu(&cdev->rcu_node);
        spin_unlock(&cdev_rcu_lock);
        synchronize_rcu();

        cxgbi_device_destroy(cdev);
}
EXPORT_SYMBOL_GPL(cxgbi_device_unregister);

void cxgbi_device_unregister_all(unsigned int flag)
{
        struct cxgbi_device *cdev, *tmp;

        mutex_lock(&cdev_mutex);
        list_for_each_entry_safe(cdev, tmp, &cdev_list, list_head) {
                if ((cdev->flags & flag) == flag) {
                        mutex_unlock(&cdev_mutex);
                        cxgbi_device_unregister(cdev);
                        mutex_lock(&cdev_mutex);
                }
        }
        mutex_unlock(&cdev_mutex);
}
EXPORT_SYMBOL_GPL(cxgbi_device_unregister_all);

struct cxgbi_device *cxgbi_device_find_by_lldev(void *lldev)
{
        struct cxgbi_device *cdev, *tmp;

        mutex_lock(&cdev_mutex);
        list_for_each_entry_safe(cdev, tmp, &cdev_list, list_head) {
                if (cdev->lldev == lldev) {
                        mutex_unlock(&cdev_mutex);
                        return cdev;
                }
        }
        mutex_unlock(&cdev_mutex);

        log_debug(1 << CXGBI_DBG_DEV,
                "lldev 0x%p, NO match found.\n", lldev);
        return NULL;
}
EXPORT_SYMBOL_GPL(cxgbi_device_find_by_lldev);

struct cxgbi_device *cxgbi_device_find_by_netdev(struct net_device *ndev,
                                                 int *port)
{
        struct net_device *vdev = NULL;
        struct cxgbi_device *cdev, *tmp;
        int i;

        if (ndev->priv_flags & IFF_802_1Q_VLAN) {
                vdev = ndev;
                ndev = vlan_dev_real_dev(ndev);
                log_debug(1 << CXGBI_DBG_DEV,
                        "vlan dev %s -> %s.\n", vdev->name, ndev->name);
        }

        mutex_lock(&cdev_mutex);
        list_for_each_entry_safe(cdev, tmp, &cdev_list, list_head) {
                for (i = 0; i < cdev->nports; i++) {
                        if (ndev == cdev->ports[i]) {
                                cdev->hbas[i]->vdev = vdev;
                                mutex_unlock(&cdev_mutex);
                                if (port)
                                        *port = i;
                                return cdev;
                        }
                }
        }
        mutex_unlock(&cdev_mutex);
        log_debug(1 << CXGBI_DBG_DEV,
                "ndev 0x%p, %s, NO match found.\n", ndev, ndev->name);
        return NULL;
}
EXPORT_SYMBOL_GPL(cxgbi_device_find_by_netdev);

struct cxgbi_device *cxgbi_device_find_by_netdev_rcu(struct net_device *ndev,
                                                     int *port)
{
        struct net_device *vdev = NULL;
        struct cxgbi_device *cdev;
        int i;

        if (ndev->priv_flags & IFF_802_1Q_VLAN) {
                vdev = ndev;
                ndev = vlan_dev_real_dev(ndev);
                pr_info("vlan dev %s -> %s.\n", vdev->name, ndev->name);
        }

        rcu_read_lock();
        list_for_each_entry_rcu(cdev, &cdev_rcu_list, rcu_node) {
                for (i = 0; i < cdev->nports; i++) {
                        if (ndev == cdev->ports[i]) {
                                cdev->hbas[i]->vdev = vdev;
                                rcu_read_unlock();
                                if (port)
                                        *port = i;
                                return cdev;
                        }
                }
        }
        rcu_read_unlock();

        log_debug(1 << CXGBI_DBG_DEV,
                  "ndev 0x%p, %s, NO match found.\n", ndev, ndev->name);
        return NULL;
}
EXPORT_SYMBOL_GPL(cxgbi_device_find_by_netdev_rcu);

#if IS_ENABLED(CONFIG_IPV6)
static struct cxgbi_device *cxgbi_device_find_by_mac(struct net_device *ndev,
                                                     int *port)
{
        struct net_device *vdev = NULL;
        struct cxgbi_device *cdev, *tmp;
        int i;

        if (ndev->priv_flags & IFF_802_1Q_VLAN) {
                vdev = ndev;
                ndev = vlan_dev_real_dev(ndev);
                pr_info("vlan dev %s -> %s.\n", vdev->name, ndev->name);
        }

        mutex_lock(&cdev_mutex);
        list_for_each_entry_safe(cdev, tmp, &cdev_list, list_head) {
                for (i = 0; i < cdev->nports; i++) {
                        if (!memcmp(ndev->dev_addr, cdev->ports[i]->dev_addr,
                                    MAX_ADDR_LEN)) {
                                cdev->hbas[i]->vdev = vdev;
                                mutex_unlock(&cdev_mutex);
                                if (port)
                                        *port = i;
                                return cdev;
                        }
                }
        }
        mutex_unlock(&cdev_mutex);
        log_debug(1 << CXGBI_DBG_DEV,
                  "ndev 0x%p, %s, NO match mac found.\n",
                  ndev, ndev->name);
        return NULL;
}
#endif

void cxgbi_hbas_remove(struct cxgbi_device *cdev)
{
        int i;
        struct cxgbi_hba *chba;

        log_debug(1 << CXGBI_DBG_DEV,
                "cdev 0x%p, p#%u.\n", cdev, cdev->nports);

        for (i = 0; i < cdev->nports; i++) {
                chba = cdev->hbas[i];
                if (chba) {
                        cdev->hbas[i] = NULL;
                        iscsi_host_remove(chba->shost);
                        pci_dev_put(cdev->pdev);
                        iscsi_host_free(chba->shost);
                }
        }
}
EXPORT_SYMBOL_GPL(cxgbi_hbas_remove);

int cxgbi_hbas_add(struct cxgbi_device *cdev, u64 max_lun,
                unsigned int max_id, struct scsi_host_template *sht,
                struct scsi_transport_template *stt)
{
        struct cxgbi_hba *chba;
        struct Scsi_Host *shost;
        int i, err;

        log_debug(1 << CXGBI_DBG_DEV, "cdev 0x%p, p#%u.\n", cdev, cdev->nports);

        for (i = 0; i < cdev->nports; i++) {
                shost = iscsi_host_alloc(sht, sizeof(*chba), 1);
                if (!shost) {
                        pr_info("0x%p, p%d, %s, host alloc failed.\n",
                                cdev, i, cdev->ports[i]->name);
                        err = -ENOMEM;
                        goto err_out;
                }

                shost->transportt = stt;
                shost->max_lun = max_lun;
                shost->max_id = max_id;
                shost->max_channel = 0;
                shost->max_cmd_len = 16;

                chba = iscsi_host_priv(shost);
                chba->cdev = cdev;
                chba->ndev = cdev->ports[i];
                chba->shost = shost;

                log_debug(1 << CXGBI_DBG_DEV,
                        "cdev 0x%p, p#%d %s: chba 0x%p.\n",
                        cdev, i, cdev->ports[i]->name, chba);

                pci_dev_get(cdev->pdev);
                err = iscsi_host_add(shost, &cdev->pdev->dev);
                if (err) {
                        pr_info("cdev 0x%p, p#%d %s, host add failed.\n",
                                cdev, i, cdev->ports[i]->name);
                        pci_dev_put(cdev->pdev);
                        scsi_host_put(shost);
                        goto  err_out;
                }

                cdev->hbas[i] = chba;
        }

        return 0;

err_out:
        cxgbi_hbas_remove(cdev);
        return err;
}
EXPORT_SYMBOL_GPL(cxgbi_hbas_add);

/*
 * iSCSI offload
 *
 * - source port management
 *   To find a free source port in the port allocation map we use a very simple
 *   rotor scheme to look for the next free port.
 *
 *   If a source port has been specified make sure that it doesn't collide with
 *   our normal source port allocation map.  If it's outside the range of our
 *   allocation/deallocation scheme just let them use it.
 *
 *   If the source port is outside our allocation range, the caller is
 *   responsible for keeping track of their port usage.
 */

static struct cxgbi_sock *find_sock_on_port(struct cxgbi_device *cdev,
                                            unsigned char port_id)
{
        struct cxgbi_ports_map *pmap = &cdev->pmap;
        unsigned int i;
        unsigned int used;

        if (!pmap->max_connect || !pmap->used)
                return NULL;

        spin_lock_bh(&pmap->lock);
        used = pmap->used;
        for (i = 0; used && i < pmap->max_connect; i++) {
                struct cxgbi_sock *csk = pmap->port_csk[i];

                if (csk) {
                        if (csk->port_id == port_id) {
                                spin_unlock_bh(&pmap->lock);
                                return csk;
                        }
                        used--;
                }
        }
        spin_unlock_bh(&pmap->lock);

        return NULL;
}

static int sock_get_port(struct cxgbi_sock *csk)
{
        struct cxgbi_device *cdev = csk->cdev;
        struct cxgbi_ports_map *pmap = &cdev->pmap;
        unsigned int start;
        int idx;
        __be16 *port;

        if (!pmap->max_connect) {
                pr_err("cdev 0x%p, p#%u %s, NO port map.\n",
                           cdev, csk->port_id, cdev->ports[csk->port_id]->name);
                return -EADDRNOTAVAIL;
        }

        if (csk->csk_family == AF_INET)
                port = &csk->saddr.sin_port;
        else /* ipv6 */
                port = &csk->saddr6.sin6_port;

        if (*port) {
                pr_err("source port NON-ZERO %u.\n",
                        ntohs(*port));
                return -EADDRINUSE;
        }

        spin_lock_bh(&pmap->lock);
        if (pmap->used >= pmap->max_connect) {
                spin_unlock_bh(&pmap->lock);
                pr_info("cdev 0x%p, p#%u %s, ALL ports used.\n",
                        cdev, csk->port_id, cdev->ports[csk->port_id]->name);
                return -EADDRNOTAVAIL;
        }

        start = idx = pmap->next;
        do {
                if (++idx >= pmap->max_connect)
                        idx = 0;
                if (!pmap->port_csk[idx]) {
                        pmap->used++;
                        *port = htons(pmap->sport_base + idx);
                        pmap->next = idx;
                        pmap->port_csk[idx] = csk;
                        spin_unlock_bh(&pmap->lock);
                        cxgbi_sock_get(csk);
                        log_debug(1 << CXGBI_DBG_SOCK,
                                "cdev 0x%p, p#%u %s, p %u, %u.\n",
                                cdev, csk->port_id,
                                cdev->ports[csk->port_id]->name,
                                pmap->sport_base + idx, pmap->next);
                        return 0;
                }
        } while (idx != start);
        spin_unlock_bh(&pmap->lock);

        /* should not happen */
        pr_warn("cdev 0x%p, p#%u %s, next %u?\n",
                cdev, csk->port_id, cdev->ports[csk->port_id]->name,
                pmap->next);
        return -EADDRNOTAVAIL;
}

static void sock_put_port(struct cxgbi_sock *csk)
{
        struct cxgbi_device *cdev = csk->cdev;
        struct cxgbi_ports_map *pmap = &cdev->pmap;
        __be16 *port;

        if (csk->csk_family == AF_INET)
                port = &csk->saddr.sin_port;
        else /* ipv6 */
                port = &csk->saddr6.sin6_port;

        if (*port) {
                int idx = ntohs(*port) - pmap->sport_base;

                *port = 0;
                if (idx < 0 || idx >= pmap->max_connect) {
                        pr_err("cdev 0x%p, p#%u %s, port %u OOR.\n",
                                cdev, csk->port_id,
                                cdev->ports[csk->port_id]->name,
                                ntohs(*port));
                        return;
                }

                spin_lock_bh(&pmap->lock);
                pmap->port_csk[idx] = NULL;
                pmap->used--;
                spin_unlock_bh(&pmap->lock);

                log_debug(1 << CXGBI_DBG_SOCK,
                        "cdev 0x%p, p#%u %s, release %u.\n",
                        cdev, csk->port_id, cdev->ports[csk->port_id]->name,
                        pmap->sport_base + idx);

                cxgbi_sock_put(csk);
        }
}

/*
 * iscsi tcp connection
 */
void cxgbi_sock_free_cpl_skbs(struct cxgbi_sock *csk)
{
        if (csk->cpl_close) {
                kfree_skb(csk->cpl_close);
                csk->cpl_close = NULL;
        }
        if (csk->cpl_abort_req) {
                kfree_skb(csk->cpl_abort_req);
                csk->cpl_abort_req = NULL;
        }
        if (csk->cpl_abort_rpl) {
                kfree_skb(csk->cpl_abort_rpl);
                csk->cpl_abort_rpl = NULL;
        }
}
EXPORT_SYMBOL_GPL(cxgbi_sock_free_cpl_skbs);

static struct cxgbi_sock *cxgbi_sock_create(struct cxgbi_device *cdev)
{
        struct cxgbi_sock *csk = kzalloc(sizeof(*csk), GFP_NOIO);

        if (!csk) {
                pr_info("alloc csk %zu failed.\n", sizeof(*csk));
                return NULL;
        }

        if (cdev->csk_alloc_cpls(csk) < 0) {
                pr_info("csk 0x%p, alloc cpls failed.\n", csk);
                kfree(csk);
                return NULL;
        }

        spin_lock_init(&csk->lock);
        kref_init(&csk->refcnt);
        skb_queue_head_init(&csk->receive_queue);
        skb_queue_head_init(&csk->write_queue);
        setup_timer(&csk->retry_timer, NULL, (unsigned long)csk);
        rwlock_init(&csk->callback_lock);
        csk->cdev = cdev;
        csk->flags = 0;
        cxgbi_sock_set_state(csk, CTP_CLOSED);

        log_debug(1 << CXGBI_DBG_SOCK, "cdev 0x%p, new csk 0x%p.\n", cdev, csk);

        return csk;
}

static struct rtable *find_route_ipv4(struct flowi4 *fl4,
                                      __be32 saddr, __be32 daddr,
                                      __be16 sport, __be16 dport, u8 tos)
{
        struct rtable *rt;

        rt = ip_route_output_ports(&init_net, fl4, NULL, daddr, saddr,
                                   dport, sport, IPPROTO_TCP, tos, 0);
        if (IS_ERR(rt))
                return NULL;

        return rt;
}

static struct cxgbi_sock *cxgbi_check_route(struct sockaddr *dst_addr)
{
        struct sockaddr_in *daddr = (struct sockaddr_in *)dst_addr;
        struct dst_entry *dst;
        struct net_device *ndev;
        struct cxgbi_device *cdev;
        struct rtable *rt = NULL;
        struct neighbour *n;
        struct flowi4 fl4;
        struct cxgbi_sock *csk = NULL;
        unsigned int mtu = 0;
        int port = 0xFFFF;
        int err = 0;

        rt = find_route_ipv4(&fl4, 0, daddr->sin_addr.s_addr, 0, daddr->sin_port, 0);
        if (!rt) {
                pr_info("no route to ipv4 0x%x, port %u.\n",
                        be32_to_cpu(daddr->sin_addr.s_addr),
                        be16_to_cpu(daddr->sin_port));
                err = -ENETUNREACH;
                goto err_out;
        }
        dst = &rt->dst;
        n = dst_neigh_lookup(dst, &daddr->sin_addr.s_addr);
        if (!n) {
                err = -ENODEV;
                goto rel_rt;
        }
        ndev = n->dev;

        if (rt->rt_flags & (RTCF_MULTICAST | RTCF_BROADCAST)) {
                pr_info("multi-cast route %pI4, port %u, dev %s.\n",
                        &daddr->sin_addr.s_addr, ntohs(daddr->sin_port),
                        ndev->name);
                err = -ENETUNREACH;
                goto rel_neigh;
        }

        if (ndev->flags & IFF_LOOPBACK) {
                ndev = ip_dev_find(&init_net, daddr->sin_addr.s_addr);
                mtu = ndev->mtu;
                pr_info("rt dev %s, loopback -> %s, mtu %u.\n",
                        n->dev->name, ndev->name, mtu);
        }

        cdev = cxgbi_device_find_by_netdev(ndev, &port);
        if (!cdev) {
                pr_info("dst %pI4, %s, NOT cxgbi device.\n",
                        &daddr->sin_addr.s_addr, ndev->name);
                err = -ENETUNREACH;
                goto rel_neigh;
        }
        log_debug(1 << CXGBI_DBG_SOCK,
                "route to %pI4 :%u, ndev p#%d,%s, cdev 0x%p.\n",
                &daddr->sin_addr.s_addr, ntohs(daddr->sin_port),
                           port, ndev->name, cdev);

        csk = cxgbi_sock_create(cdev);
        if (!csk) {
                err = -ENOMEM;
                goto rel_neigh;
        }
        csk->cdev = cdev;
        csk->port_id = port;
        csk->mtu = mtu;
        csk->dst = dst;

        csk->csk_family = AF_INET;
        csk->daddr.sin_addr.s_addr = daddr->sin_addr.s_addr;
        csk->daddr.sin_port = daddr->sin_port;
        csk->daddr.sin_family = daddr->sin_family;
        csk->saddr.sin_family = daddr->sin_family;
        csk->saddr.sin_addr.s_addr = fl4.saddr;
        neigh_release(n);

        return csk;

rel_neigh:
        neigh_release(n);

rel_rt:
        ip_rt_put(rt);
        if (csk)
                cxgbi_sock_closed(csk);
err_out:
        return ERR_PTR(err);
}

#if IS_ENABLED(CONFIG_IPV6)
static struct rt6_info *find_route_ipv6(const struct in6_addr *saddr,
                                        const struct in6_addr *daddr)
{
        struct flowi6 fl;

        if (saddr)
                memcpy(&fl.saddr, saddr, sizeof(struct in6_addr));
        if (daddr)
                memcpy(&fl.daddr, daddr, sizeof(struct in6_addr));
        return (struct rt6_info *)ip6_route_output(&init_net, NULL, &fl);
}

static struct cxgbi_sock *cxgbi_check_route6(struct sockaddr *dst_addr)
{
        struct sockaddr_in6 *daddr6 = (struct sockaddr_in6 *)dst_addr;
        struct dst_entry *dst;
        struct net_device *ndev;
        struct cxgbi_device *cdev;
        struct rt6_info *rt = NULL;
        struct neighbour *n;
        struct in6_addr pref_saddr;
        struct cxgbi_sock *csk = NULL;
        unsigned int mtu = 0;
        int port = 0xFFFF;
        int err = 0;

        rt = find_route_ipv6(NULL, &daddr6->sin6_addr);

        if (!rt) {
                pr_info("no route to ipv6 %pI6 port %u\n",
                        daddr6->sin6_addr.s6_addr,
                        be16_to_cpu(daddr6->sin6_port));
                err = -ENETUNREACH;
                goto err_out;
        }

        dst = &rt->dst;

        n = dst_neigh_lookup(dst, &daddr6->sin6_addr);

        if (!n) {
                pr_info("%pI6, port %u, dst no neighbour.\n",
                        daddr6->sin6_addr.s6_addr,
                        be16_to_cpu(daddr6->sin6_port));
                err = -ENETUNREACH;
                goto rel_rt;
        }
        ndev = n->dev;

        if (ipv6_addr_is_multicast(&rt->rt6i_dst.addr)) {
                pr_info("multi-cast route %pI6 port %u, dev %s.\n",
                        daddr6->sin6_addr.s6_addr,
                        ntohs(daddr6->sin6_port), ndev->name);
                err = -ENETUNREACH;
                goto rel_rt;
        }

        cdev = cxgbi_device_find_by_netdev(ndev, &port);
        if (!cdev)
                cdev = cxgbi_device_find_by_mac(ndev, &port);
        if (!cdev) {
                pr_info("dst %pI6 %s, NOT cxgbi device.\n",
                        daddr6->sin6_addr.s6_addr, ndev->name);
                err = -ENETUNREACH;
                goto rel_rt;
        }
        log_debug(1 << CXGBI_DBG_SOCK,
                  "route to %pI6 :%u, ndev p#%d,%s, cdev 0x%p.\n",
                  daddr6->sin6_addr.s6_addr, ntohs(daddr6->sin6_port), port,
                  ndev->name, cdev);

        csk = cxgbi_sock_create(cdev);
        if (!csk) {
                err = -ENOMEM;
                goto rel_rt;
        }
        csk->cdev = cdev;
        csk->port_id = port;
        csk->mtu = mtu;
        csk->dst = dst;

        if (ipv6_addr_any(&rt->rt6i_prefsrc.addr)) {
                struct inet6_dev *idev = ip6_dst_idev((struct dst_entry *)rt);

                err = ipv6_dev_get_saddr(&init_net, idev ? idev->dev : NULL,
                                         &daddr6->sin6_addr, 0, &pref_saddr);
                if (err) {
                        pr_info("failed to get source address to reach %pI6\n",
                                &daddr6->sin6_addr);
                        goto rel_rt;
                }
        } else {
                pref_saddr = rt->rt6i_prefsrc.addr;
        }

        csk->csk_family = AF_INET6;
        csk->daddr6.sin6_addr = daddr6->sin6_addr;
        csk->daddr6.sin6_port = daddr6->sin6_port;
        csk->daddr6.sin6_family = daddr6->sin6_family;
        csk->saddr6.sin6_family = daddr6->sin6_family;
        csk->saddr6.sin6_addr = pref_saddr;

        neigh_release(n);
        return csk;

rel_rt:
        if (n)
                neigh_release(n);

        ip6_rt_put(rt);
        if (csk)
                cxgbi_sock_closed(csk);
err_out:
        return ERR_PTR(err);
}
#endif /* IS_ENABLED(CONFIG_IPV6) */

void cxgbi_sock_established(struct cxgbi_sock *csk, unsigned int snd_isn,
                        unsigned int opt)
{
        csk->write_seq = csk->snd_nxt = csk->snd_una = snd_isn;
        dst_confirm(csk->dst);
        smp_mb();
        cxgbi_sock_set_state(csk, CTP_ESTABLISHED);
}
EXPORT_SYMBOL_GPL(cxgbi_sock_established);

static void cxgbi_inform_iscsi_conn_closing(struct cxgbi_sock *csk)
{
        log_debug(1 << CXGBI_DBG_SOCK,
                "csk 0x%p, state %u, flags 0x%lx, conn 0x%p.\n",
                csk, csk->state, csk->flags, csk->user_data);

        if (csk->state != CTP_ESTABLISHED) {
                read_lock_bh(&csk->callback_lock);
                if (csk->user_data)
                        iscsi_conn_failure(csk->user_data,
                                        ISCSI_ERR_TCP_CONN_CLOSE);
                read_unlock_bh(&csk->callback_lock);
        }
}

void cxgbi_sock_closed(struct cxgbi_sock *csk)
{
        log_debug(1 << CXGBI_DBG_SOCK, "csk 0x%p,%u,0x%lx,%u.\n",
                csk, (csk)->state, (csk)->flags, (csk)->tid);
        cxgbi_sock_set_flag(csk, CTPF_ACTIVE_CLOSE_NEEDED);
        if (csk->state == CTP_ACTIVE_OPEN || csk->state == CTP_CLOSED)
                return;
        if (csk->saddr.sin_port)
                sock_put_port(csk);
        if (csk->dst)
                dst_release(csk->dst);
        csk->cdev->csk_release_offload_resources(csk);
        cxgbi_sock_set_state(csk, CTP_CLOSED);
        cxgbi_inform_iscsi_conn_closing(csk);
        cxgbi_sock_put(csk);
}
EXPORT_SYMBOL_GPL(cxgbi_sock_closed);

static void need_active_close(struct cxgbi_sock *csk)
{
        int data_lost;
        int close_req = 0;

        log_debug(1 << CXGBI_DBG_SOCK, "csk 0x%p,%u,0x%lx,%u.\n",
                csk, (csk)->state, (csk)->flags, (csk)->tid);
        spin_lock_bh(&csk->lock);
        dst_confirm(csk->dst);
        data_lost = skb_queue_len(&csk->receive_queue);
        __skb_queue_purge(&csk->receive_queue);

        if (csk->state == CTP_ACTIVE_OPEN)
                cxgbi_sock_set_flag(csk, CTPF_ACTIVE_CLOSE_NEEDED);
        else if (csk->state == CTP_ESTABLISHED) {
                close_req = 1;
                cxgbi_sock_set_state(csk, CTP_ACTIVE_CLOSE);
        } else if (csk->state == CTP_PASSIVE_CLOSE) {
                close_req = 1;
                cxgbi_sock_set_state(csk, CTP_CLOSE_WAIT_2);
        }

        if (close_req) {
                if (data_lost)
                        csk->cdev->csk_send_abort_req(csk);
                else
                        csk->cdev->csk_send_close_req(csk);
        }

        spin_unlock_bh(&csk->lock);
}

void cxgbi_sock_fail_act_open(struct cxgbi_sock *csk, int errno)
{
        pr_info("csk 0x%p,%u,%lx, %pI4:%u-%pI4:%u, err %d.\n",
                        csk, csk->state, csk->flags,
                        &csk->saddr.sin_addr.s_addr, csk->saddr.sin_port,
                        &csk->daddr.sin_addr.s_addr, csk->daddr.sin_port,
                        errno);

        cxgbi_sock_set_state(csk, CTP_CONNECTING);
        csk->err = errno;
        cxgbi_sock_closed(csk);
}
EXPORT_SYMBOL_GPL(cxgbi_sock_fail_act_open);

void cxgbi_sock_act_open_req_arp_failure(void *handle, struct sk_buff *skb)
{
        struct cxgbi_sock *csk = (struct cxgbi_sock *)skb->sk;

        log_debug(1 << CXGBI_DBG_SOCK, "csk 0x%p,%u,0x%lx,%u.\n",
                csk, (csk)->state, (csk)->flags, (csk)->tid);
        cxgbi_sock_get(csk);
        spin_lock_bh(&csk->lock);
        if (csk->state == CTP_ACTIVE_OPEN)
                cxgbi_sock_fail_act_open(csk, -EHOSTUNREACH);
        spin_unlock_bh(&csk->lock);
        cxgbi_sock_put(csk);
        __kfree_skb(skb);
}
EXPORT_SYMBOL_GPL(cxgbi_sock_act_open_req_arp_failure);

void cxgbi_sock_rcv_abort_rpl(struct cxgbi_sock *csk)
{
        cxgbi_sock_get(csk);
        spin_lock_bh(&csk->lock);

        cxgbi_sock_set_flag(csk, CTPF_ABORT_RPL_RCVD);
        if (cxgbi_sock_flag(csk, CTPF_ABORT_RPL_PENDING)) {
                cxgbi_sock_clear_flag(csk, CTPF_ABORT_RPL_PENDING);
                if (cxgbi_sock_flag(csk, CTPF_ABORT_REQ_RCVD))
                        pr_err("csk 0x%p,%u,0x%lx,%u,ABT_RPL_RSS.\n",
                               csk, csk->state, csk->flags, csk->tid);
                cxgbi_sock_closed(csk);
        }

        spin_unlock_bh(&csk->lock);
        cxgbi_sock_put(csk);
}
EXPORT_SYMBOL_GPL(cxgbi_sock_rcv_abort_rpl);

void cxgbi_sock_rcv_peer_close(struct cxgbi_sock *csk)
{
        log_debug(1 << CXGBI_DBG_SOCK, "csk 0x%p,%u,0x%lx,%u.\n",
                csk, (csk)->state, (csk)->flags, (csk)->tid);
        cxgbi_sock_get(csk);
        spin_lock_bh(&csk->lock);

        if (cxgbi_sock_flag(csk, CTPF_ABORT_RPL_PENDING))
                goto done;

        switch (csk->state) {
        case CTP_ESTABLISHED:
                cxgbi_sock_set_state(csk, CTP_PASSIVE_CLOSE);
                break;
        case CTP_ACTIVE_CLOSE:
                cxgbi_sock_set_state(csk, CTP_CLOSE_WAIT_2);
                break;
        case CTP_CLOSE_WAIT_1:
                cxgbi_sock_closed(csk);
                break;
        case CTP_ABORTING:
                break;
        default:
                pr_err("csk 0x%p,%u,0x%lx,%u, bad state.\n",
                        csk, csk->state, csk->flags, csk->tid);
        }
        cxgbi_inform_iscsi_conn_closing(csk);
done:
        spin_unlock_bh(&csk->lock);
        cxgbi_sock_put(csk);
}
EXPORT_SYMBOL_GPL(cxgbi_sock_rcv_peer_close);

void cxgbi_sock_rcv_close_conn_rpl(struct cxgbi_sock *csk, u32 snd_nxt)
{
        log_debug(1 << CXGBI_DBG_SOCK, "csk 0x%p,%u,0x%lx,%u.\n",
                csk, (csk)->state, (csk)->flags, (csk)->tid);
        cxgbi_sock_get(csk);
        spin_lock_bh(&csk->lock);

        csk->snd_una = snd_nxt - 1;
        if (cxgbi_sock_flag(csk, CTPF_ABORT_RPL_PENDING))
                goto done;

        switch (csk->state) {
        case CTP_ACTIVE_CLOSE:
                cxgbi_sock_set_state(csk, CTP_CLOSE_WAIT_1);
                break;
        case CTP_CLOSE_WAIT_1:
        case CTP_CLOSE_WAIT_2:
                cxgbi_sock_closed(csk);
                break;
        case CTP_ABORTING:
                break;
        default:
                pr_err("csk 0x%p,%u,0x%lx,%u, bad state.\n",
                        csk, csk->state, csk->flags, csk->tid);
        }
done:
        spin_unlock_bh(&csk->lock);
        cxgbi_sock_put(csk);
}
EXPORT_SYMBOL_GPL(cxgbi_sock_rcv_close_conn_rpl);

void cxgbi_sock_rcv_wr_ack(struct cxgbi_sock *csk, unsigned int credits,
                           unsigned int snd_una, int seq_chk)
{
        log_debug(1 << CXGBI_DBG_TOE | 1 << CXGBI_DBG_SOCK,
                        "csk 0x%p,%u,0x%lx,%u, cr %u,%u+%u, snd_una %u,%d.\n",
                        csk, csk->state, csk->flags, csk->tid, credits,
                        csk->wr_cred, csk->wr_una_cred, snd_una, seq_chk);

        spin_lock_bh(&csk->lock);

        csk->wr_cred += credits;
        if (csk->wr_una_cred > csk->wr_max_cred - csk->wr_cred)
                csk->wr_una_cred = csk->wr_max_cred - csk->wr_cred;

        while (credits) {
                struct sk_buff *p = cxgbi_sock_peek_wr(csk);

                if (unlikely(!p)) {
                        pr_err("csk 0x%p,%u,0x%lx,%u, cr %u,%u+%u, empty.\n",
                                csk, csk->state, csk->flags, csk->tid, credits,
                                csk->wr_cred, csk->wr_una_cred);
                        break;
                }

                if (unlikely(credits < p->csum)) {
                        pr_warn("csk 0x%p,%u,0x%lx,%u, cr %u,%u+%u, < %u.\n",
                                csk, csk->state, csk->flags, csk->tid,
                                credits, csk->wr_cred, csk->wr_una_cred,
                                p->csum);
                        p->csum -= credits;
                        break;
                } else {
                        cxgbi_sock_dequeue_wr(csk);
                        credits -= p->csum;
                        kfree_skb(p);
                }
        }

        cxgbi_sock_check_wr_invariants(csk);

        if (seq_chk) {
                if (unlikely(before(snd_una, csk->snd_una))) {
                        pr_warn("csk 0x%p,%u,0x%lx,%u, snd_una %u/%u.",
                                csk, csk->state, csk->flags, csk->tid, snd_una,
                                csk->snd_una);
                        goto done;
                }

                if (csk->snd_una != snd_una) {
                        csk->snd_una = snd_una;
                        dst_confirm(csk->dst);
                }
        }

        if (skb_queue_len(&csk->write_queue)) {
                if (csk->cdev->csk_push_tx_frames(csk, 0))
                        cxgbi_conn_tx_open(csk);
        } else
                cxgbi_conn_tx_open(csk);
done:
        spin_unlock_bh(&csk->lock);
}
EXPORT_SYMBOL_GPL(cxgbi_sock_rcv_wr_ack);

static unsigned int cxgbi_sock_find_best_mtu(struct cxgbi_sock *csk,
                                             unsigned short mtu)
{
        int i = 0;

        while (i < csk->cdev->nmtus - 1 && csk->cdev->mtus[i + 1] <= mtu)
                ++i;

        return i;
}

unsigned int cxgbi_sock_select_mss(struct cxgbi_sock *csk, unsigned int pmtu)
{
        unsigned int idx;
        struct dst_entry *dst = csk->dst;

        csk->advmss = dst_metric_advmss(dst);

        if (csk->advmss > pmtu - 40)
                csk->advmss = pmtu - 40;
        if (csk->advmss < csk->cdev->mtus[0] - 40)
                csk->advmss = csk->cdev->mtus[0] - 40;
        idx = cxgbi_sock_find_best_mtu(csk, csk->advmss + 40);

        return idx;
}
EXPORT_SYMBOL_GPL(cxgbi_sock_select_mss);

void cxgbi_sock_skb_entail(struct cxgbi_sock *csk, struct sk_buff *skb)
{
        cxgbi_skcb_tcp_seq(skb) = csk->write_seq;
        __skb_queue_tail(&csk->write_queue, skb);
}
EXPORT_SYMBOL_GPL(cxgbi_sock_skb_entail);

void cxgbi_sock_purge_wr_queue(struct cxgbi_sock *csk)
{
        struct sk_buff *skb;

        while ((skb = cxgbi_sock_dequeue_wr(csk)) != NULL)
                kfree_skb(skb);
}
EXPORT_SYMBOL_GPL(cxgbi_sock_purge_wr_queue);

void cxgbi_sock_check_wr_invariants(const struct cxgbi_sock *csk)
{
        int pending = cxgbi_sock_count_pending_wrs(csk);

        if (unlikely(csk->wr_cred + pending != csk->wr_max_cred))
                pr_err("csk 0x%p, tid %u, credit %u + %u != %u.\n",
                        csk, csk->tid, csk->wr_cred, pending, csk->wr_max_cred);
}
EXPORT_SYMBOL_GPL(cxgbi_sock_check_wr_invariants);

static int cxgbi_sock_send_pdus(struct cxgbi_sock *csk, struct sk_buff *skb)
{
        struct cxgbi_device *cdev = csk->cdev;
        struct sk_buff *next;
        int err, copied = 0;

        spin_lock_bh(&csk->lock);

        if (csk->state != CTP_ESTABLISHED) {
                log_debug(1 << CXGBI_DBG_PDU_TX,
                        "csk 0x%p,%u,0x%lx,%u, EAGAIN.\n",
                        csk, csk->state, csk->flags, csk->tid);
                err = -EAGAIN;
                goto out_err;
        }

        if (csk->err) {
                log_debug(1 << CXGBI_DBG_PDU_TX,
                        "csk 0x%p,%u,0x%lx,%u, EPIPE %d.\n",
                        csk, csk->state, csk->flags, csk->tid, csk->err);
                err = -EPIPE;
                goto out_err;
        }

        if (csk->write_seq - csk->snd_una >= cdev->snd_win) {
                log_debug(1 << CXGBI_DBG_PDU_TX,
                        "csk 0x%p,%u,0x%lx,%u, FULL %u-%u >= %u.\n",
                        csk, csk->state, csk->flags, csk->tid, csk->write_seq,
                        csk->snd_una, cdev->snd_win);
                err = -ENOBUFS;
                goto out_err;
        }

        while (skb) {
                int frags = skb_shinfo(skb)->nr_frags +
                                (skb->len != skb->data_len);

                if (unlikely(skb_headroom(skb) < cdev->skb_tx_rsvd)) {
                        pr_err("csk 0x%p, skb head %u < %u.\n",
                                csk, skb_headroom(skb), cdev->skb_tx_rsvd);
                        err = -EINVAL;
                        goto out_err;
                }

                if (frags >= SKB_WR_LIST_SIZE) {
                        pr_err("csk 0x%p, frags %d, %u,%u >%u.\n",
                                csk, skb_shinfo(skb)->nr_frags, skb->len,
                                skb->data_len, (uint)(SKB_WR_LIST_SIZE));
                        err = -EINVAL;
                        goto out_err;
                }

                next = skb->next;
                skb->next = NULL;
                cxgbi_skcb_set_flag(skb, SKCBF_TX_NEED_HDR);
                cxgbi_sock_skb_entail(csk, skb);
                copied += skb->len;
                csk->write_seq += skb->len +
                                cxgbi_ulp_extra_len(cxgbi_skcb_ulp_mode(skb));
                skb = next;
        }
done:
        if (likely(skb_queue_len(&csk->write_queue)))
                cdev->csk_push_tx_frames(csk, 1);
        spin_unlock_bh(&csk->lock);
        return copied;

out_err:
        if (copied == 0 && err == -EPIPE)
                copied = csk->err ? csk->err : -EPIPE;
        else
                copied = err;
        goto done;
}

/*
 * Direct Data Placement -
 * 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.
 * The host memory address is programmed into h/w in the format of pagepod
 * entries.
 * The location of the pagepod entry is encoded into ddp tag which is used as
 * the base for ITT/TTT.
 */

static unsigned char ddp_page_order[DDP_PGIDX_MAX] = {0, 1, 2, 4};
static unsigned char ddp_page_shift[DDP_PGIDX_MAX] = {12, 13, 14, 16};
static unsigned char page_idx = DDP_PGIDX_MAX;

static unsigned char sw_tag_idx_bits;
static unsigned char sw_tag_age_bits;

/*
 * Direct-Data Placement page size adjustment
 */
static int ddp_adjust_page_table(void)
{
        int i;
        unsigned int base_order, order;

        if (PAGE_SIZE < (1UL << ddp_page_shift[0])) {
                pr_info("PAGE_SIZE 0x%lx too small, min 0x%lx\n",
                        PAGE_SIZE, 1UL << ddp_page_shift[0]);
                return -EINVAL;
        }

        base_order = get_order(1UL << ddp_page_shift[0]);
        order = get_order(1UL << PAGE_SHIFT);

        for (i = 0; i < DDP_PGIDX_MAX; i++) {
                /* first is the kernel page size, then just doubling */
                ddp_page_order[i] = order - base_order + i;
                ddp_page_shift[i] = PAGE_SHIFT + i;
        }
        return 0;
}

static int ddp_find_page_index(unsigned long pgsz)
{
        int i;

        for (i = 0; i < DDP_PGIDX_MAX; i++) {
                if (pgsz == (1UL << ddp_page_shift[i]))
                        return i;
        }
        pr_info("ddp page size %lu not supported.\n", pgsz);
        return DDP_PGIDX_MAX;
}

static void ddp_setup_host_page_size(void)
{
        if (page_idx == DDP_PGIDX_MAX) {
                page_idx = ddp_find_page_index(PAGE_SIZE);

                if (page_idx == DDP_PGIDX_MAX) {
                        pr_info("system PAGE %lu, update hw.\n", PAGE_SIZE);
                        if (ddp_adjust_page_table() < 0) {
                                pr_info("PAGE %lu, disable ddp.\n", PAGE_SIZE);
                                return;
                        }
                        page_idx = ddp_find_page_index(PAGE_SIZE);
                }
                pr_info("system PAGE %lu, ddp idx %u.\n", PAGE_SIZE, page_idx);
        }
}

void cxgbi_ddp_page_size_factor(int *pgsz_factor)
{
        int i;

        for (i = 0; i < DDP_PGIDX_MAX; i++)
                pgsz_factor[i] = ddp_page_order[i];
}
EXPORT_SYMBOL_GPL(cxgbi_ddp_page_size_factor);

/*
 * DDP setup & teardown
 */

void cxgbi_ddp_ppod_set(struct cxgbi_pagepod *ppod,
                        struct cxgbi_pagepod_hdr *hdr,
                        struct cxgbi_gather_list *gl, unsigned int gidx)
{
        int i;

        memcpy(ppod, hdr, sizeof(*hdr));
        for (i = 0; i < (PPOD_PAGES_MAX + 1); i++, gidx++) {
                ppod->addr[i] = gidx < gl->nelem ?
                                cpu_to_be64(gl->phys_addr[gidx]) : 0ULL;
        }
}
EXPORT_SYMBOL_GPL(cxgbi_ddp_ppod_set);

void cxgbi_ddp_ppod_clear(struct cxgbi_pagepod *ppod)
{
        memset(ppod, 0, sizeof(*ppod));
}
EXPORT_SYMBOL_GPL(cxgbi_ddp_ppod_clear);

static inline int ddp_find_unused_entries(struct cxgbi_ddp_info *ddp,
                                        unsigned int start, unsigned int max,
                                        unsigned int count,
                                        struct cxgbi_gather_list *gl)
{
        unsigned int i, j, k;

        /*  not enough entries */
        if ((max - start) < count) {
                log_debug(1 << CXGBI_DBG_DDP,
                        "NOT enough entries %u+%u < %u.\n", start, count, max);
                return -EBUSY;
        }

        max -= count;
        spin_lock(&ddp->map_lock);
        for (i = start; i < max;) {
                for (j = 0, k = i; j < count; j++, k++) {
                        if (ddp->gl_map[k])
                                break;
                }
                if (j == count) {
                        for (j = 0, k = i; j < count; j++, k++)
                                ddp->gl_map[k] = gl;
                        spin_unlock(&ddp->map_lock);
                        return i;
                }
                i += j + 1;
        }
        spin_unlock(&ddp->map_lock);
        log_debug(1 << CXGBI_DBG_DDP,
                "NO suitable entries %u available.\n", count);
        return -EBUSY;
}

static inline void ddp_unmark_entries(struct cxgbi_ddp_info *ddp,
                                                int start, int count)
{
        spin_lock(&ddp->map_lock);
        memset(&ddp->gl_map[start], 0,
                count * sizeof(struct cxgbi_gather_list *));
        spin_unlock(&ddp->map_lock);
}

static inline void ddp_gl_unmap(struct pci_dev *pdev,
                                        struct cxgbi_gather_list *gl)
{
        int i;

        for (i = 0; i < gl->nelem; i++)
                dma_unmap_page(&pdev->dev, gl->phys_addr[i], PAGE_SIZE,
                                PCI_DMA_FROMDEVICE);
}

static inline int ddp_gl_map(struct pci_dev *pdev,
                                    struct cxgbi_gather_list *gl)
{
        int i;

        for (i = 0; i < gl->nelem; i++) {
                gl->phys_addr[i] = dma_map_page(&pdev->dev, gl->pages[i], 0,
                                                PAGE_SIZE,
                                                PCI_DMA_FROMDEVICE);
                if (unlikely(dma_mapping_error(&pdev->dev, gl->phys_addr[i]))) {
                        log_debug(1 << CXGBI_DBG_DDP,
                                "page %d 0x%p, 0x%p dma mapping err.\n",
                                i, gl->pages[i], pdev);
                        goto unmap;
                }
        }
        return i;
unmap:
        if (i) {
                unsigned int nelem = gl->nelem;

                gl->nelem = i;
                ddp_gl_unmap(pdev, gl);
                gl->nelem = nelem;
        }
        return -EINVAL;
}

static void ddp_release_gl(struct cxgbi_gather_list *gl,
                                  struct pci_dev *pdev)
{
        ddp_gl_unmap(pdev, gl);
        kfree(gl);
}

static struct cxgbi_gather_list *ddp_make_gl(unsigned int xferlen,
                                                    struct scatterlist *sgl,
                                                    unsigned int sgcnt,
                                                    struct pci_dev *pdev,
                                                    gfp_t gfp)
{
        struct cxgbi_gather_list *gl;
        struct scatterlist *sg = sgl;
        struct page *sgpage = sg_page(sg);
        unsigned int sglen = sg->length;
        unsigned int sgoffset = sg->offset;
        unsigned int npages = (xferlen + sgoffset + PAGE_SIZE - 1) >>
                                PAGE_SHIFT;
        int i = 1, j = 0;

        if (xferlen < DDP_THRESHOLD) {
                log_debug(1 << CXGBI_DBG_DDP,
                        "xfer %u < threshold %u, no ddp.\n",
                        xferlen, DDP_THRESHOLD);
                return NULL;
        }

        gl = kzalloc(sizeof(struct cxgbi_gather_list) +
                     npages * (sizeof(dma_addr_t) +
                     sizeof(struct page *)), gfp);
        if (!gl) {
                log_debug(1 << CXGBI_DBG_DDP,
                        "xfer %u, %u pages, OOM.\n", xferlen, npages);
                return NULL;
        }

         log_debug(1 << CXGBI_DBG_DDP,
                "xfer %u, sgl %u, gl max %u.\n", xferlen, sgcnt, npages);

        gl->pages = (struct page **)&gl->phys_addr[npages];
        gl->nelem = npages;
        gl->length = xferlen;
        gl->offset = sgoffset;
        gl->pages[0] = sgpage;

        for (i = 1, sg = sg_next(sgl), j = 0; i < sgcnt;
                i++, sg = sg_next(sg)) {
                struct page *page = sg_page(sg);

                if (sgpage == page && sg->offset == sgoffset + sglen)
                        sglen += sg->length;
                else {
                        /*  make sure the sgl is fit for ddp:
                         *  each has the same page size, and
                         *  all of the middle pages are used completely
                         */
                        if ((j && sgoffset) || ((i != sgcnt - 1) &&
                            ((sglen + sgoffset) & ~PAGE_MASK))) {
                                log_debug(1 << CXGBI_DBG_DDP,
                                        "page %d/%u, %u + %u.\n",
                                        i, sgcnt, sgoffset, sglen);
                                goto error_out;
                        }

                        j++;
                        if (j == gl->nelem || sg->offset) {
                                log_debug(1 << CXGBI_DBG_DDP,
                                        "page %d/%u, offset %u.\n",
                                        j, gl->nelem, sg->offset);
                                goto error_out;
                        }
                        gl->pages[j] = page;
                        sglen = sg->length;
                        sgoffset = sg->offset;
                        sgpage = page;
                }
        }
        gl->nelem = ++j;

        if (ddp_gl_map(pdev, gl) < 0)
                goto error_out;

        return gl;

error_out:
        kfree(gl);
        return NULL;
}

static void ddp_tag_release(struct cxgbi_hba *chba, u32 tag)
{
        struct cxgbi_device *cdev = chba->cdev;
        struct cxgbi_ddp_info *ddp = cdev->ddp;
        u32 idx;

        idx = (tag >> PPOD_IDX_SHIFT) & ddp->idx_mask;
        if (idx < ddp->nppods) {
                struct cxgbi_gather_list *gl = ddp->gl_map[idx];
                unsigned int npods;

                if (!gl || !gl->nelem) {
                        pr_warn("tag 0x%x, idx %u, gl 0x%p, %u.\n",
                                tag, idx, gl, gl ? gl->nelem : 0);
                        return;
                }
                npods = (gl->nelem + PPOD_PAGES_MAX - 1) >> PPOD_PAGES_SHIFT;
                log_debug(1 << CXGBI_DBG_DDP,
                        "tag 0x%x, release idx %u, npods %u.\n",
                        tag, idx, npods);
                cdev->csk_ddp_clear(chba, tag, idx, npods);
                ddp_unmark_entries(ddp, idx, npods);
                ddp_release_gl(gl, ddp->pdev);
        } else
                pr_warn("tag 0x%x, idx %u > max %u.\n", tag, idx, ddp->nppods);
}

static int ddp_tag_reserve(struct cxgbi_sock *csk, unsigned int tid,
                           u32 sw_tag, u32 *tagp, struct cxgbi_gather_list *gl,
                           gfp_t gfp)
{
        struct cxgbi_device *cdev = csk->cdev;
        struct cxgbi_ddp_info *ddp = cdev->ddp;
        struct cxgbi_tag_format *tformat = &cdev->tag_format;
        struct cxgbi_pagepod_hdr hdr;
        unsigned int npods;
        int idx = -1;
        int err = -ENOMEM;
        u32 tag;

        npods = (gl->nelem + PPOD_PAGES_MAX - 1) >> PPOD_PAGES_SHIFT;
        if (ddp->idx_last == ddp->nppods)
                idx = ddp_find_unused_entries(ddp, 0, ddp->nppods,
                                                        npods, gl);
        else {
                idx = ddp_find_unused_entries(ddp, ddp->idx_last + 1,
                                                        ddp->nppods, npods,
                                                        gl);
                if (idx < 0 && ddp->idx_last >= npods) {
                        idx = ddp_find_unused_entries(ddp, 0,
                                min(ddp->idx_last + npods, ddp->nppods),
                                                        npods, gl);
                }
        }
        if (idx < 0) {
                log_debug(1 << CXGBI_DBG_DDP,
                        "xferlen %u, gl %u, npods %u NO DDP.\n",
                        gl->length, gl->nelem, npods);
                return idx;
        }

        tag = cxgbi_ddp_tag_base(tformat, sw_tag);
        tag |= idx << PPOD_IDX_SHIFT;

        hdr.rsvd = 0;
        hdr.vld_tid = htonl(PPOD_VALID_FLAG | PPOD_TID(tid));
        hdr.pgsz_tag_clr = htonl(tag & ddp->rsvd_tag_mask);
        hdr.max_offset = htonl(gl->length);
        hdr.page_offset = htonl(gl->offset);

        err = cdev->csk_ddp_set(csk, &hdr, idx, npods, gl);
        if (err < 0)
                goto unmark_entries;

        ddp->idx_last = idx;
        log_debug(1 << CXGBI_DBG_DDP,
                "xfer %u, gl %u,%u, tid 0x%x, tag 0x%x->0x%x(%u,%u).\n",
                gl->length, gl->nelem, gl->offset, tid, sw_tag, tag, idx,
                npods);
        *tagp = tag;
        return 0;

unmark_entries:
        ddp_unmark_entries(ddp, idx, npods);
        return err;
}

int cxgbi_ddp_reserve(struct cxgbi_sock *csk, unsigned int *tagp,
                        unsigned int sw_tag, unsigned int xferlen,
                        struct scatterlist *sgl, unsigned int sgcnt, gfp_t gfp)
{
        struct cxgbi_device *cdev = csk->cdev;
        struct cxgbi_tag_format *tformat = &cdev->tag_format;
        struct cxgbi_gather_list *gl;
        int err;

        if (page_idx >= DDP_PGIDX_MAX || !cdev->ddp ||
            xferlen < DDP_THRESHOLD) {
                log_debug(1 << CXGBI_DBG_DDP,
                        "pgidx %u, xfer %u, NO ddp.\n", page_idx, xferlen);
                return -EINVAL;
        }

        if (!cxgbi_sw_tag_usable(tformat, sw_tag)) {
                log_debug(1 << CXGBI_DBG_DDP,
                        "sw_tag 0x%x NOT usable.\n", sw_tag);
                return -EINVAL;
        }

        gl = ddp_make_gl(xferlen, sgl, sgcnt, cdev->pdev, gfp);
        if (!gl)
                return -ENOMEM;

        err = ddp_tag_reserve(csk, csk->tid, sw_tag, tagp, gl, gfp);
        if (err < 0)
                ddp_release_gl(gl, cdev->pdev);

        return err;
}

static void ddp_destroy(struct kref *kref)
{
        struct cxgbi_ddp_info *ddp = container_of(kref,
                                                struct cxgbi_ddp_info,
                                                refcnt);
        struct cxgbi_device *cdev = ddp->cdev;
        int i = 0;

        pr_info("kref 0, destroy ddp 0x%p, cdev 0x%p.\n", ddp, cdev);

        while (i < ddp->nppods) {
                struct cxgbi_gather_list *gl = ddp->gl_map[i];

                if (gl) {
                        int npods = (gl->nelem + PPOD_PAGES_MAX - 1)
                                        >> PPOD_PAGES_SHIFT;
                        pr_info("cdev 0x%p, ddp %d + %d.\n", cdev, i, npods);
                        kfree(gl);
                        i += npods;
                } else
                        i++;
        }
        cxgbi_free_big_mem(ddp);
}

int cxgbi_ddp_cleanup(struct cxgbi_device *cdev)
{
        struct cxgbi_ddp_info *ddp = cdev->ddp;

        log_debug(1 << CXGBI_DBG_DDP,
                "cdev 0x%p, release ddp 0x%p.\n", cdev, ddp);
        cdev->ddp = NULL;
        if (ddp)
                return kref_put(&ddp->refcnt, ddp_destroy);
        return 0;
}
EXPORT_SYMBOL_GPL(cxgbi_ddp_cleanup);

int cxgbi_ddp_init(struct cxgbi_device *cdev,
                   unsigned int llimit, unsigned int ulimit,
                   unsigned int max_txsz, unsigned int max_rxsz)
{
        struct cxgbi_ddp_info *ddp;
        unsigned int ppmax, bits;

        ppmax = (ulimit - llimit + 1) >> PPOD_SIZE_SHIFT;
        bits = __ilog2_u32(ppmax) + 1;
        if (bits > PPOD_IDX_MAX_SIZE)
                bits = PPOD_IDX_MAX_SIZE;
        ppmax = (1 << (bits - 1)) - 1;

        ddp = cxgbi_alloc_big_mem(sizeof(struct cxgbi_ddp_info) +
                                ppmax * (sizeof(struct cxgbi_gather_list *) +
                                         sizeof(struct sk_buff *)),
                                GFP_KERNEL);
        if (!ddp) {
                pr_warn("cdev 0x%p, ddp ppmax %u OOM.\n", cdev, ppmax);
                return -ENOMEM;
        }
        ddp->gl_map = (struct cxgbi_gather_list **)(ddp + 1);
        cdev->ddp = ddp;

        spin_lock_init(&ddp->map_lock);
        kref_init(&ddp->refcnt);

        ddp->cdev = cdev;
        ddp->pdev = cdev->pdev;
        ddp->llimit = llimit;
        ddp->ulimit = ulimit;
        ddp->max_txsz = min_t(unsigned int, max_txsz, ULP2_MAX_PKT_SIZE);
        ddp->max_rxsz = min_t(unsigned int, max_rxsz, ULP2_MAX_PKT_SIZE);
        ddp->nppods = ppmax;
        ddp->idx_last = ppmax;
        ddp->idx_bits = bits;
        ddp->idx_mask = (1 << bits) - 1;
        ddp->rsvd_tag_mask = (1 << (bits + PPOD_IDX_SHIFT)) - 1;

        cdev->tag_format.sw_bits = sw_tag_idx_bits + sw_tag_age_bits;
        cdev->tag_format.rsvd_bits = ddp->idx_bits;
        cdev->tag_format.rsvd_shift = PPOD_IDX_SHIFT;
        cdev->tag_format.rsvd_mask = (1 << cdev->tag_format.rsvd_bits) - 1;

        pr_info("%s tag format, sw %u, rsvd %u,%u, mask 0x%x.\n",
                cdev->ports[0]->name, cdev->tag_format.sw_bits,
                cdev->tag_format.rsvd_bits, cdev->tag_format.rsvd_shift,
                cdev->tag_format.rsvd_mask);

        cdev->tx_max_size = min_t(unsigned int, ULP2_MAX_PDU_PAYLOAD,
                                ddp->max_txsz - ISCSI_PDU_NONPAYLOAD_LEN);
        cdev->rx_max_size = min_t(unsigned int, ULP2_MAX_PDU_PAYLOAD,
                                ddp->max_rxsz - ISCSI_PDU_NONPAYLOAD_LEN);

        log_debug(1 << CXGBI_DBG_DDP,
                "%s max payload size: %u/%u, %u/%u.\n",
                cdev->ports[0]->name, cdev->tx_max_size, ddp->max_txsz,
                cdev->rx_max_size, ddp->max_rxsz);
        return 0;
}
EXPORT_SYMBOL_GPL(cxgbi_ddp_init);

/*
 * APIs interacting with open-iscsi libraries
 */

static unsigned char padding[4];

static void task_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 cxgbi_conn *cconn = tcp_conn->dd_data;
        struct cxgbi_hba *chba = cconn->chba;
        struct cxgbi_tag_format *tformat = &chba->cdev->tag_format;
        u32 tag = ntohl((__force u32)hdr_itt);

        log_debug(1 << CXGBI_DBG_DDP,
                   "cdev 0x%p, release tag 0x%x.\n", chba->cdev, tag);
        if (sc &&
            (scsi_bidi_cmnd(sc) || sc->sc_data_direction == DMA_FROM_DEVICE) &&
            cxgbi_is_ddp_tag(tformat, tag))
                ddp_tag_release(chba, tag);
}

static int task_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 cxgbi_conn *cconn = tcp_conn->dd_data;
        struct cxgbi_hba *chba = cconn->chba;
        struct cxgbi_tag_format *tformat = &chba->cdev->tag_format;
        u32 sw_tag = (sess->age << cconn->task_idx_bits) | task->itt;
        u32 tag = 0;
        int err = -EINVAL;

        if (sc &&
            (scsi_bidi_cmnd(sc) || sc->sc_data_direction == DMA_FROM_DEVICE)) {
                err = cxgbi_ddp_reserve(cconn->cep->csk, &tag, sw_tag,
                                        scsi_in(sc)->length,
                                        scsi_in(sc)->table.sgl,
                                        scsi_in(sc)->table.nents,
                                        GFP_ATOMIC);
                if (err < 0)
                        log_debug(1 << CXGBI_DBG_DDP,
                                "csk 0x%p, R task 0x%p, %u,%u, no ddp.\n",
                                cconn->cep->csk, task, scsi_in(sc)->length,
                                scsi_in(sc)->table.nents);
        }

        if (err < 0)
                tag = cxgbi_set_non_ddp_tag(tformat, sw_tag);
        /*  the itt need to sent in big-endian order */
        *hdr_itt = (__force itt_t)htonl(tag);

        log_debug(1 << CXGBI_DBG_DDP,
                "cdev 0x%p, task 0x%p, 0x%x(0x%x,0x%x)->0x%x/0x%x.\n",
                chba->cdev, task, sw_tag, task->itt, sess->age, tag, *hdr_itt);
        return 0;
}

void cxgbi_parse_pdu_itt(struct iscsi_conn *conn, itt_t itt, int *idx, int *age)
{
        struct iscsi_tcp_conn *tcp_conn = conn->dd_data;
        struct cxgbi_conn *cconn = tcp_conn->dd_data;
        struct cxgbi_device *cdev = cconn->chba->cdev;
        u32 tag = ntohl((__force u32) itt);
        u32 sw_bits;

        sw_bits = cxgbi_tag_nonrsvd_bits(&cdev->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;

        log_debug(1 << CXGBI_DBG_DDP,
                "cdev 0x%p, tag 0x%x/0x%x, -> 0x%x(0x%x,0x%x).\n",
                cdev, tag, itt, sw_bits, idx ? *idx : 0xFFFFF,
                age ? *age : 0xFF);
}
EXPORT_SYMBOL_GPL(cxgbi_parse_pdu_itt);

void cxgbi_conn_tx_open(struct cxgbi_sock *csk)
{
        struct iscsi_conn *conn = csk->user_data;

        if (conn) {
                log_debug(1 << CXGBI_DBG_SOCK,
                        "csk 0x%p, cid %d.\n", csk, conn->id);
                iscsi_conn_queue_work(conn);
        }
}
EXPORT_SYMBOL_GPL(cxgbi_conn_tx_open);

/*
 * 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:
                pr_info("skb 0x%p, off %u, %d, TCP_ERR.\n",
                          skb, offset, offloaded);
                return -EIO;
        case ISCSI_TCP_SUSPENDED:
                log_debug(1 << CXGBI_DBG_PDU_RX,
                        "skb 0x%p, off %u, %d, TCP_SUSPEND, rc %d.\n",
                        skb, offset, offloaded, bytes_read);
                /* no transfer - just have caller flush queue */
                return bytes_read;
        case ISCSI_TCP_SKB_DONE:
                pr_info("skb 0x%p, off %u, %d, TCP_SKB_DONE.\n",
                        skb, offset, offloaded);
                /*
                 * 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:
                log_debug(1 << CXGBI_DBG_PDU_RX,
                        "skb 0x%p, off %u, %d, TCP_SEG_DONE, rc %d.\n",
                        skb, offset, offloaded, bytes_read);
                return bytes_read;
        default:
                pr_info("skb 0x%p, off %u, %d, invalid status %d.\n",
                        skb, offset, offloaded, status);
                return -EINVAL;
        }
}

static int skb_read_pdu_bhs(struct iscsi_conn *conn, struct sk_buff *skb)
{
        struct iscsi_tcp_conn *tcp_conn = conn->dd_data;

        log_debug(1 << CXGBI_DBG_PDU_RX,
                "conn 0x%p, skb 0x%p, len %u, flag 0x%lx.\n",
                conn, skb, skb->len, cxgbi_skcb_flags(skb));

        if (!iscsi_tcp_recv_segment_is_hdr(tcp_conn)) {
                pr_info("conn 0x%p, skb 0x%p, not hdr.\n", conn, skb);
                iscsi_conn_failure(conn, ISCSI_ERR_PROTO);
                return -EIO;
        }

        if (conn->hdrdgst_en &&
            cxgbi_skcb_test_flag(skb, SKCBF_RX_HCRC_ERR)) {
                pr_info("conn 0x%p, skb 0x%p, hcrc.\n", conn, skb);
                iscsi_conn_failure(conn, ISCSI_ERR_HDR_DGST);
                return -EIO;
        }

        return read_pdu_skb(conn, skb, 0, 0);
}

static int skb_read_pdu_data(struct iscsi_conn *conn, struct sk_buff *lskb,
                             struct sk_buff *skb, unsigned int offset)
{
        struct iscsi_tcp_conn *tcp_conn = conn->dd_data;
        bool offloaded = 0;
        int opcode = tcp_conn->in.hdr->opcode & ISCSI_OPCODE_MASK;

        log_debug(1 << CXGBI_DBG_PDU_RX,
                "conn 0x%p, skb 0x%p, len %u, flag 0x%lx.\n",
                conn, skb, skb->len, cxgbi_skcb_flags(skb));

        if (conn->datadgst_en &&
            cxgbi_skcb_test_flag(lskb, SKCBF_RX_DCRC_ERR)) {
                pr_info("conn 0x%p, skb 0x%p, dcrc 0x%lx.\n",
                        conn, lskb, cxgbi_skcb_flags(lskb));
                iscsi_conn_failure(conn, ISCSI_ERR_DATA_DGST);
                return -EIO;
        }

        if (iscsi_tcp_recv_segment_is_hdr(tcp_conn))
                return 0;

        /* coalesced, add header digest length */
        if (lskb == skb && conn->hdrdgst_en)
                offset += ISCSI_DIGEST_SIZE;

        if (cxgbi_skcb_test_flag(lskb, SKCBF_RX_DATA_DDPD))
                offloaded = 1;

        if (opcode == ISCSI_OP_SCSI_DATA_IN)
                log_debug(1 << CXGBI_DBG_PDU_RX,
                        "skb 0x%p, op 0x%x, itt 0x%x, %u %s ddp'ed.\n",
                        skb, opcode, ntohl(tcp_conn->in.hdr->itt),
                        tcp_conn->in.datalen, offloaded ? "is" : "not");

        return read_pdu_skb(conn, skb, offset, offloaded);
}

static void csk_return_rx_credits(struct cxgbi_sock *csk, int copied)
{
        struct cxgbi_device *cdev = csk->cdev;
        int must_send;
        u32 credits;

        log_debug(1 << CXGBI_DBG_PDU_RX,
                "csk 0x%p,%u,0x%lx,%u, seq %u, wup %u, thre %u, %u.\n",
                csk, csk->state, csk->flags, csk->tid, csk->copied_seq,
                csk->rcv_wup, cdev->rx_credit_thres,
                cdev->rcv_win);

        if (csk->state != CTP_ESTABLISHED)
                return;

        credits = csk->copied_seq - csk->rcv_wup;
        if (unlikely(!credits))
                return;
        if (unlikely(cdev->rx_credit_thres == 0))
                return;

        must_send = credits + 16384 >= cdev->rcv_win;
        if (must_send || credits >= cdev->rx_credit_thres)
                csk->rcv_wup += cdev->csk_send_rx_credits(csk, credits);
}

void cxgbi_conn_pdu_ready(struct cxgbi_sock *csk)
{
        struct cxgbi_device *cdev = csk->cdev;
        struct iscsi_conn *conn = csk->user_data;
        struct sk_buff *skb;
        unsigned int read = 0;
        int err = 0;

        log_debug(1 << CXGBI_DBG_PDU_RX,
                "csk 0x%p, conn 0x%p.\n", csk, conn);

        if (unlikely(!conn || conn->suspend_rx)) {
                log_debug(1 << CXGBI_DBG_PDU_RX,
                        "csk 0x%p, conn 0x%p, id %d, suspend_rx %lu!\n",
                        csk, conn, conn ? conn->id : 0xFF,
                        conn ? conn->suspend_rx : 0xFF);
                return;
        }

        while (!err) {
                skb = skb_peek(&csk->receive_queue);
                if (!skb ||
                    !(cxgbi_skcb_test_flag(skb, SKCBF_RX_STATUS))) {
                        if (skb)
                                log_debug(1 << CXGBI_DBG_PDU_RX,
                                        "skb 0x%p, NOT ready 0x%lx.\n",
                                        skb, cxgbi_skcb_flags(skb));
                        break;
                }
                __skb_unlink(skb, &csk->receive_queue);

                read += cxgbi_skcb_rx_pdulen(skb);
                log_debug(1 << CXGBI_DBG_PDU_RX,
                        "csk 0x%p, skb 0x%p,%u,f 0x%lx, pdu len %u.\n",
                        csk, skb, skb->len, cxgbi_skcb_flags(skb),
                        cxgbi_skcb_rx_pdulen(skb));

                if (cxgbi_skcb_test_flag(skb, SKCBF_RX_COALESCED)) {
                        err = skb_read_pdu_bhs(conn, skb);
                        if (err < 0) {
                                pr_err("coalesced bhs, csk 0x%p, skb 0x%p,%u, "
                                        "f 0x%lx, plen %u.\n",
                                        csk, skb, skb->len,
                                        cxgbi_skcb_flags(skb),
                                        cxgbi_skcb_rx_pdulen(skb));
                                goto skb_done;
                        }
                        err = skb_read_pdu_data(conn, skb, skb,
                                                err + cdev->skb_rx_extra);
                        if (err < 0)
                                pr_err("coalesced data, csk 0x%p, skb 0x%p,%u, "
                                        "f 0x%lx, plen %u.\n",
                                        csk, skb, skb->len,
                                        cxgbi_skcb_flags(skb),
                                        cxgbi_skcb_rx_pdulen(skb));
                } else {
                        err = skb_read_pdu_bhs(conn, skb);
                        if (err < 0) {
                                pr_err("bhs, csk 0x%p, skb 0x%p,%u, "
                                        "f 0x%lx, plen %u.\n",
                                        csk, skb, skb->len,
                                        cxgbi_skcb_flags(skb),
                                        cxgbi_skcb_rx_pdulen(skb));
                                goto skb_done;
                        }

                        if (cxgbi_skcb_test_flag(skb, SKCBF_RX_DATA)) {
                                struct sk_buff *dskb;

                                dskb = skb_peek(&csk->receive_queue);
                                if (!dskb) {
                                        pr_err("csk 0x%p, skb 0x%p,%u, f 0x%lx,"
                                                " plen %u, NO data.\n",
                                                csk, skb, skb->len,
                                                cxgbi_skcb_flags(skb),
                                                cxgbi_skcb_rx_pdulen(skb));
                                        err = -EIO;
                                        goto skb_done;
                                }
                                __skb_unlink(dskb, &csk->receive_queue);

                                err = skb_read_pdu_data(conn, skb, dskb, 0);
                                if (err < 0)
                                        pr_err("data, csk 0x%p, skb 0x%p,%u, "
                                                "f 0x%lx, plen %u, dskb 0x%p,"
                                                "%u.\n",
                                                csk, skb, skb->len,
                                                cxgbi_skcb_flags(skb),
                                                cxgbi_skcb_rx_pdulen(skb),
                                                dskb, dskb->len);
                                __kfree_skb(dskb);
                        } else
                                err = skb_read_pdu_data(conn, skb, skb, 0);
                }
skb_done:
                __kfree_skb(skb);

                if (err < 0)
                        break;
        }

        log_debug(1 << CXGBI_DBG_PDU_RX, "csk 0x%p, read %u.\n", csk, read);
        if (read) {
                csk->copied_seq += read;
                csk_return_rx_credits(csk, read);
                conn->rxdata_octets += read;
        }

        if (err < 0) {
                pr_info("csk 0x%p, 0x%p, rx failed %d, read %u.\n",
                        csk, conn, err, read);
                iscsi_conn_failure(conn, ISCSI_ERR_CONN_FAILED);
        }
}
EXPORT_SYMBOL_GPL(cxgbi_conn_pdu_ready);

static int sgl_seek_offset(struct scatterlist *sgl, unsigned int sgcnt,
                                unsigned int offset, unsigned int *off,
                                struct scatterlist **sgp)
{
        int i;
        struct scatterlist *sg;

        for_each_sg(sgl, sg, sgcnt, i) {
                if (offset < sg->length) {
                        *off = offset;
                        *sgp = sg;
                        return 0;
                }
                offset -= sg->length;
        }
        return -EFAULT;
}

static int sgl_read_to_frags(struct scatterlist *sg, unsigned int sgoffset,
                                unsigned int dlen, struct page_frag *frags,
                                int frag_max)
{
        unsigned int datalen = dlen;
        unsigned int sglen = sg->length - sgoffset;
        struct page *page = sg_page(sg);
        int i;

        i = 0;
        do {
                unsigned int copy;

                if (!sglen) {
                        sg = sg_next(sg);
                        if (!sg) {
                                pr_warn("sg %d NULL, len %u/%u.\n",
                                        i, datalen, dlen);
                                return -EINVAL;
                        }
                        sgoffset = 0;
                        sglen = sg->length;
                        page = sg_page(sg);

                }
                copy = min(datalen, sglen);
                if (i && page == frags[i - 1].page &&
                    sgoffset + sg->offset ==
                        frags[i - 1].offset + frags[i - 1].size) {
                        frags[i - 1].size += copy;
                } else {
                        if (i >= frag_max) {
                                pr_warn("too many pages %u, dlen %u.\n",
                                        frag_max, dlen);
                                return -EINVAL;
                        }

                        frags[i].page = page;
                        frags[i].offset = sg->offset + sgoffset;
                        frags[i].size = copy;
                        i++;
                }
                datalen -= copy;
                sgoffset += copy;
                sglen -= copy;
        } while (datalen);

        return i;
}

int cxgbi_conn_alloc_pdu(struct iscsi_task *task, u8 opcode)
{
        struct iscsi_tcp_conn *tcp_conn = task->conn->dd_data;
        struct cxgbi_conn *cconn = tcp_conn->dd_data;
        struct cxgbi_device *cdev = cconn->chba->cdev;
        struct iscsi_conn *conn = task->conn;
        struct iscsi_tcp_task *tcp_task = task->dd_data;
        struct cxgbi_task_data *tdata = iscsi_task_cxgbi_data(task);
        struct scsi_cmnd *sc = task->sc;
        int headroom = SKB_TX_ISCSI_PDU_HEADER_MAX;

        tcp_task->dd_data = tdata;
        task->hdr = NULL;

        if (SKB_MAX_HEAD(cdev->skb_tx_rsvd) > (512 * MAX_SKB_FRAGS) &&
            (opcode == ISCSI_OP_SCSI_DATA_OUT ||
             (opcode == ISCSI_OP_SCSI_CMD &&
              (scsi_bidi_cmnd(sc) || sc->sc_data_direction == DMA_TO_DEVICE))))
                /* data could goes into skb head */
                headroom += min_t(unsigned int,
                                SKB_MAX_HEAD(cdev->skb_tx_rsvd),
                                conn->max_xmit_dlength);

        tdata->skb = alloc_skb(cdev->skb_tx_rsvd + headroom, GFP_ATOMIC);
        if (!tdata->skb) {
                struct cxgbi_sock *csk = cconn->cep->csk;
                struct net_device *ndev = cdev->ports[csk->port_id];
                ndev->stats.tx_dropped++;
                return -ENOMEM;
        }

        skb_reserve(tdata->skb, cdev->skb_tx_rsvd);
        task->hdr = (struct iscsi_hdr *)tdata->skb->data;
        task->hdr_max = SKB_TX_ISCSI_PDU_HEADER_MAX; /* BHS + AHS */

        /* data_out uses scsi_cmd's itt */
        if (opcode != ISCSI_OP_SCSI_DATA_OUT)
                task_reserve_itt(task, &task->hdr->itt);

        log_debug(1 << CXGBI_DBG_ISCSI | 1 << CXGBI_DBG_PDU_TX,
                "task 0x%p, op 0x%x, skb 0x%p,%u+%u/%u, itt 0x%x.\n",
                task, opcode, tdata->skb, cdev->skb_tx_rsvd, headroom,
                conn->max_xmit_dlength, ntohl(task->hdr->itt));

        return 0;
}
EXPORT_SYMBOL_GPL(cxgbi_conn_alloc_pdu);

static inline void tx_skb_setmode(struct sk_buff *skb, int hcrc, int dcrc)
{
        if (hcrc || dcrc) {
                u8 submode = 0;

                if (hcrc)
                        submode |= 1;
                if (dcrc)
                        submode |= 2;
                cxgbi_skcb_ulp_mode(skb) = (ULP2_MODE_ISCSI << 4) | submode;
        } else
                cxgbi_skcb_ulp_mode(skb) = 0;
}

int cxgbi_conn_init_pdu(struct iscsi_task *task, unsigned int offset,
                              unsigned int count)
{
        struct iscsi_conn *conn = task->conn;
        struct cxgbi_task_data *tdata = iscsi_task_cxgbi_data(task);
        struct sk_buff *skb = tdata->skb;
        unsigned int datalen = count;
        int i, padlen = iscsi_padding(count);
        struct page *pg;

        log_debug(1 << CXGBI_DBG_ISCSI | 1 << CXGBI_DBG_PDU_TX,
                "task 0x%p,0x%p, skb 0x%p, 0x%x,0x%x,0x%x, %u+%u.\n",
                task, task->sc, skb, (*skb->data) & ISCSI_OPCODE_MASK,
                ntohl(task->cmdsn), ntohl(task->hdr->itt), offset, count);

        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 scsi_data_buffer *sdb = scsi_out(task->sc);
                struct scatterlist *sg = NULL;
                int err;

                tdata->offset = offset;
                tdata->count = count;
                err = sgl_seek_offset(
                                        sdb->table.sgl, sdb->table.nents,
                                        tdata->offset, &tdata->sgoffset, &sg);
                if (err < 0) {
                        pr_warn("tpdu, sgl %u, bad offset %u/%u.\n",
                                sdb->table.nents, tdata->offset, sdb->length);
                        return err;
                }
                err = sgl_read_to_frags(sg, tdata->sgoffset, tdata->count,
                                        tdata->frags, MAX_PDU_FRAGS);
                if (err < 0) {
                        pr_warn("tpdu, sgl %u, bad offset %u + %u.\n",
                                sdb->table.nents, tdata->offset, tdata->count);
                        return err;
                }
                tdata->nr_frags = err;

                if (tdata->nr_frags > MAX_SKB_FRAGS ||
                    (padlen && tdata->nr_frags == MAX_SKB_FRAGS)) {
                        char *dst = skb->data + task->hdr_len;
                        struct page_frag *frag = tdata->frags;

                        /* data fits in the skb's headroom */
                        for (i = 0; i < tdata->nr_frags; i++, frag++) {
                                char *src = kmap_atomic(frag->page);

                                memcpy(dst, src+frag->offset, frag->size);
                                dst += frag->size;
                                kunmap_atomic(src);
                        }
                        if (padlen) {
                                memset(dst, 0, padlen);
                                padlen = 0;
                        }
                        skb_put(skb, count + padlen);
                } else {
                        /* data fit into frag_list */
                        for (i = 0; i < tdata->nr_frags; i++) {
                                __skb_fill_page_desc(skb, i,
                                                tdata->frags[i].page,
                                                tdata->frags[i].offset,
                                                tdata->frags[i].size);
                                skb_frag_ref(skb, i);
                        }
                        skb_shinfo(skb)->nr_frags = tdata->nr_frags;
                        skb->len += count;
                        skb->data_len += count;
                        skb->truesize += count;
                }

        } else {
                pg = virt_to_page(task->data);

                get_page(pg);
                skb_fill_page_desc(skb, 0, pg, offset_in_page(task->data),
                                        count);
                skb->len += count;
                skb->data_len += count;
                skb->truesize += count;
        }

        if (padlen) {
                i = skb_shinfo(skb)->nr_frags;
                skb_fill_page_desc(skb, skb_shinfo(skb)->nr_frags,
                                virt_to_page(padding), offset_in_page(padding),
                                padlen);

                skb->data_len += padlen;
                skb->truesize += padlen;
                skb->len += padlen;
        }

        return 0;
}
EXPORT_SYMBOL_GPL(cxgbi_conn_init_pdu);

int cxgbi_conn_xmit_pdu(struct iscsi_task *task)
{
        struct iscsi_tcp_conn *tcp_conn = task->conn->dd_data;
        struct cxgbi_conn *cconn = tcp_conn->dd_data;
        struct cxgbi_task_data *tdata = iscsi_task_cxgbi_data(task);
        struct sk_buff *skb = tdata->skb;
        unsigned int datalen;
        int err;

        if (!skb) {
                log_debug(1 << CXGBI_DBG_ISCSI | 1 << CXGBI_DBG_PDU_TX,
                        "task 0x%p, skb NULL.\n", task);
                return 0;
        }

        datalen = skb->data_len;
        tdata->skb = NULL;
        err = cxgbi_sock_send_pdus(cconn->cep->csk, skb);
        if (err > 0) {
                int pdulen = err;

                log_debug(1 << CXGBI_DBG_PDU_TX,
                        "task 0x%p,0x%p, skb 0x%p, len %u/%u, rv %d.\n",
                        task, task->sc, skb, skb->len, skb->data_len, 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 == -EAGAIN || err == -ENOBUFS) {
                log_debug(1 << CXGBI_DBG_PDU_TX,
                        "task 0x%p, skb 0x%p, len %u/%u, %d EAGAIN.\n",
                        task, skb, skb->len, skb->data_len, err);
                /* reset skb to send when we are called again */
                tdata->skb = skb;
                return err;
        }

        log_debug(1 << CXGBI_DBG_ISCSI | 1 << CXGBI_DBG_PDU_TX,
                "itt 0x%x, skb 0x%p, len %u/%u, xmit err %d.\n",
                task->itt, skb, skb->len, skb->data_len, err);

        kfree_skb(skb);

        iscsi_conn_printk(KERN_ERR, task->conn, "xmit err %d.\n", err);
        iscsi_conn_failure(task->conn, ISCSI_ERR_XMIT_FAILED);
        return err;
}
EXPORT_SYMBOL_GPL(cxgbi_conn_xmit_pdu);

void cxgbi_cleanup_task(struct iscsi_task *task)
{
        struct cxgbi_task_data *tdata = iscsi_task_cxgbi_data(task);

        log_debug(1 << CXGBI_DBG_ISCSI,
                "task 0x%p, skb 0x%p, itt 0x%x.\n",
                task, tdata->skb, task->hdr_itt);

        /*  never reached the xmit task callout */
        if (tdata->skb)
                __kfree_skb(tdata->skb);
        memset(tdata, 0, sizeof(*tdata));

        task_release_itt(task, task->hdr_itt);
        iscsi_tcp_cleanup_task(task);
}
EXPORT_SYMBOL_GPL(cxgbi_cleanup_task);

void cxgbi_get_conn_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;
}
EXPORT_SYMBOL_GPL(cxgbi_get_conn_stats);

static int cxgbi_conn_max_xmit_dlength(struct iscsi_conn *conn)
{
        struct iscsi_tcp_conn *tcp_conn = conn->dd_data;
        struct cxgbi_conn *cconn = tcp_conn->dd_data;
        struct cxgbi_device *cdev = cconn->chba->cdev;
        unsigned int headroom = SKB_MAX_HEAD(cdev->skb_tx_rsvd);
        unsigned int max_def = 512 * MAX_SKB_FRAGS;
        unsigned int max = max(max_def, headroom);

        max = min(cconn->chba->cdev->tx_max_size, max);
        if (conn->max_xmit_dlength)
                conn->max_xmit_dlength = min(conn->max_xmit_dlength, max);
        else
                conn->max_xmit_dlength = max;
        cxgbi_align_pdu_size(conn->max_xmit_dlength);

        return 0;
}

static int cxgbi_conn_max_recv_dlength(struct iscsi_conn *conn)
{
        struct iscsi_tcp_conn *tcp_conn = conn->dd_data;
        struct cxgbi_conn *cconn = tcp_conn->dd_data;
        unsigned int max = cconn->chba->cdev->rx_max_size;

        cxgbi_align_pdu_size(max);

        if (conn->max_recv_dlength) {
                if (conn->max_recv_dlength > max) {
                        pr_err("MaxRecvDataSegmentLength %u > %u.\n",
                                conn->max_recv_dlength, max);
                        return -EINVAL;
                }
                conn->max_recv_dlength = min(conn->max_recv_dlength, max);
                cxgbi_align_pdu_size(conn->max_recv_dlength);
        } else
                conn->max_recv_dlength = max;

        return 0;
}

int cxgbi_set_conn_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_tcp_conn *tcp_conn = conn->dd_data;
        struct cxgbi_conn *cconn = tcp_conn->dd_data;
        struct cxgbi_sock *csk = cconn->cep->csk;
        int err;

        log_debug(1 << CXGBI_DBG_ISCSI,
                "cls_conn 0x%p, param %d, buf(%d) %s.\n",
                cls_conn, param, buflen, buf);

        switch (param) {
        case ISCSI_PARAM_HDRDGST_EN:
                err = iscsi_set_param(cls_conn, param, buf, buflen);
                if (!err && conn->hdrdgst_en)
                        err = csk->cdev->csk_ddp_setup_digest(csk, csk->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 = csk->cdev->csk_ddp_setup_digest(csk, csk->tid,
                                                        conn->hdrdgst_en,
                                                        conn->datadgst_en, 0);
                break;
        case ISCSI_PARAM_MAX_R2T:
                return iscsi_tcp_set_max_r2t(conn, buf);
        case ISCSI_PARAM_MAX_RECV_DLENGTH:
                err = iscsi_set_param(cls_conn, param, buf, buflen);
                if (!err)
                        err = cxgbi_conn_max_recv_dlength(conn);
                break;
        case ISCSI_PARAM_MAX_XMIT_DLENGTH:
                err = iscsi_set_param(cls_conn, param, buf, buflen);
                if (!err)
                        err = cxgbi_conn_max_xmit_dlength(conn);
                break;
        default:
                return iscsi_set_param(cls_conn, param, buf, buflen);
        }
        return err;
}
EXPORT_SYMBOL_GPL(cxgbi_set_conn_param);

static inline int csk_print_port(struct cxgbi_sock *csk, char *buf)
{
        int len;

        cxgbi_sock_get(csk);
        len = sprintf(buf, "%hu\n", ntohs(csk->daddr.sin_port));
        cxgbi_sock_put(csk);

        return len;
}

static inline int csk_print_ip(struct cxgbi_sock *csk, char *buf)
{
        int len;

        cxgbi_sock_get(csk);
        if (csk->csk_family == AF_INET)
                len = sprintf(buf, "%pI4",
                              &csk->daddr.sin_addr.s_addr);
        else
                len = sprintf(buf, "%pI6",
                              &csk->daddr6.sin6_addr);

        cxgbi_sock_put(csk);

        return len;
}

int cxgbi_get_ep_param(struct iscsi_endpoint *ep, enum iscsi_param param,
                       char *buf)
{
        struct cxgbi_endpoint *cep = ep->dd_data;
        struct cxgbi_sock *csk;
        int len;

        log_debug(1 << CXGBI_DBG_ISCSI,
                "cls_conn 0x%p, param %d.\n", ep, param);

        switch (param) {
        case ISCSI_PARAM_CONN_PORT:
        case ISCSI_PARAM_CONN_ADDRESS:
                if (!cep)
                        return -ENOTCONN;

                csk = cep->csk;
                if (!csk)
                        return -ENOTCONN;

                return iscsi_conn_get_addr_param((struct sockaddr_storage *)
                                                 &csk->daddr, param, buf);
        default:
                return -ENOSYS;
        }
        return len;
}
EXPORT_SYMBOL_GPL(cxgbi_get_ep_param);

struct iscsi_cls_conn *
cxgbi_create_conn(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 cxgbi_conn *cconn;

        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->iconn = conn;

        log_debug(1 << CXGBI_DBG_ISCSI,
                "cid %u(0x%x), cls 0x%p,0x%p, conn 0x%p,0x%p,0x%p.\n",
                cid, cid, cls_session, cls_conn, conn, tcp_conn, cconn);

        return cls_conn;
}
EXPORT_SYMBOL_GPL(cxgbi_create_conn);

int cxgbi_bind_conn(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 cxgbi_conn *cconn = tcp_conn->dd_data;
        struct iscsi_endpoint *ep;
        struct cxgbi_endpoint *cep;
        struct cxgbi_sock *csk;
        int err;

        ep = iscsi_lookup_endpoint(transport_eph);
        if (!ep)
                return -EINVAL;

        /*  setup ddp pagesize */
        cep = ep->dd_data;
        csk = cep->csk;
        err = csk->cdev->csk_ddp_setup_pgidx(csk, csk->tid, page_idx, 0);
        if (err < 0)
                return err;

        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;

        write_lock_bh(&csk->callback_lock);
        csk->user_data = conn;
        cconn->chba = cep->chba;
        cconn->cep = cep;
        cep->cconn = cconn;
        write_unlock_bh(&csk->callback_lock);

        cxgbi_conn_max_xmit_dlength(conn);
        cxgbi_conn_max_recv_dlength(conn);

        log_debug(1 << CXGBI_DBG_ISCSI,
                "cls 0x%p,0x%p, ep 0x%p, cconn 0x%p, csk 0x%p.\n",
                cls_session, cls_conn, ep, cconn, csk);
        /*  init recv engine */
        iscsi_tcp_hdr_recv_prep(tcp_conn);

        return 0;
}
EXPORT_SYMBOL_GPL(cxgbi_bind_conn);

struct iscsi_cls_session *cxgbi_create_session(struct iscsi_endpoint *ep,
                                                u16 cmds_max, u16 qdepth,
                                                u32 initial_cmdsn)
{
        struct cxgbi_endpoint *cep;
        struct cxgbi_hba *chba;
        struct Scsi_Host *shost;
        struct iscsi_cls_session *cls_session;
        struct iscsi_session *session;

        if (!ep) {
                pr_err("missing endpoint.\n");
                return NULL;
        }

        cep = ep->dd_data;
        chba = cep->chba;
        shost = chba->shost;

        BUG_ON(chba != iscsi_host_priv(shost));

        cls_session = iscsi_session_setup(chba->cdev->itp, shost,
                                        cmds_max, 0,
                                        sizeof(struct iscsi_tcp_task) +
                                        sizeof(struct cxgbi_task_data),
                                        initial_cmdsn, ISCSI_MAX_TARGET);
        if (!cls_session)
                return NULL;

        session = cls_session->dd_data;
        if (iscsi_tcp_r2tpool_alloc(session))
                goto remove_session;

        log_debug(1 << CXGBI_DBG_ISCSI,
                "ep 0x%p, cls sess 0x%p.\n", ep, cls_session);
        return cls_session;

remove_session:
        iscsi_session_teardown(cls_session);
        return NULL;
}
EXPORT_SYMBOL_GPL(cxgbi_create_session);

void cxgbi_destroy_session(struct iscsi_cls_session *cls_session)
{
        log_debug(1 << CXGBI_DBG_ISCSI,
                "cls sess 0x%p.\n", cls_session);

        iscsi_tcp_r2tpool_free(cls_session->dd_data);
        iscsi_session_teardown(cls_session);
}
EXPORT_SYMBOL_GPL(cxgbi_destroy_session);

int cxgbi_set_host_param(struct Scsi_Host *shost, enum iscsi_host_param param,
                        char *buf, int buflen)
{
        struct cxgbi_hba *chba = iscsi_host_priv(shost);

        if (!chba->ndev) {
                shost_printk(KERN_ERR, shost, "Could not get host param. "
                                "netdev for host not set.\n");
                return -ENODEV;
        }

        log_debug(1 << CXGBI_DBG_ISCSI,
                "shost 0x%p, hba 0x%p,%s, param %d, buf(%d) %s.\n",
                shost, chba, chba->ndev->name, param, buflen, buf);

        switch (param) {
        case ISCSI_HOST_PARAM_IPADDRESS:
        {
                __be32 addr = in_aton(buf);
                log_debug(1 << CXGBI_DBG_ISCSI,
                        "hba %s, req. ipv4 %pI4.\n", chba->ndev->name, &addr);
                cxgbi_set_iscsi_ipv4(chba, addr);
                return 0;
        }
        case ISCSI_HOST_PARAM_HWADDRESS:
        case ISCSI_HOST_PARAM_NETDEV_NAME:
                return 0;
        default:
                return iscsi_host_set_param(shost, param, buf, buflen);
        }
}
EXPORT_SYMBOL_GPL(cxgbi_set_host_param);

int cxgbi_get_host_param(struct Scsi_Host *shost, enum iscsi_host_param param,
                        char *buf)
{
        struct cxgbi_hba *chba = iscsi_host_priv(shost);
        int len = 0;

        if (!chba->ndev) {
                shost_printk(KERN_ERR, shost, "Could not get host param. "
                                "netdev for host not set.\n");
                return -ENODEV;
        }

        log_debug(1 << CXGBI_DBG_ISCSI,
                "shost 0x%p, hba 0x%p,%s, param %d.\n",
                shost, chba, chba->ndev->name, param);

        switch (param) {
        case ISCSI_HOST_PARAM_HWADDRESS:
                len = sysfs_format_mac(buf, chba->ndev->dev_addr, 6);
                break;
        case ISCSI_HOST_PARAM_NETDEV_NAME:
                len = sprintf(buf, "%s\n", chba->ndev->name);
                break;
        case ISCSI_HOST_PARAM_IPADDRESS:
        {
                struct cxgbi_sock *csk = find_sock_on_port(chba->cdev,
                                                           chba->port_id);
                if (csk) {
                        len = sprintf(buf, "%pIS",
                                      (struct sockaddr *)&csk->saddr);
                }
                log_debug(1 << CXGBI_DBG_ISCSI,
                          "hba %s, addr %s.\n", chba->ndev->name, buf);
                break;
        }
        default:
                return iscsi_host_get_param(shost, param, buf);
        }

        return len;
}
EXPORT_SYMBOL_GPL(cxgbi_get_host_param);

struct iscsi_endpoint *cxgbi_ep_connect(struct Scsi_Host *shost,
                                        struct sockaddr *dst_addr,
                                        int non_blocking)
{
        struct iscsi_endpoint *ep;
        struct cxgbi_endpoint *cep;
        struct cxgbi_hba *hba = NULL;
        struct cxgbi_sock *csk;
        int err = -EINVAL;

        log_debug(1 << CXGBI_DBG_ISCSI | 1 << CXGBI_DBG_SOCK,
                "shost 0x%p, non_blocking %d, dst_addr 0x%p.\n",
                shost, non_blocking, dst_addr);

        if (shost) {
                hba = iscsi_host_priv(shost);
                if (!hba) {
                        pr_info("shost 0x%p, priv NULL.\n", shost);
                        goto err_out;
                }
        }

        if (dst_addr->sa_family == AF_INET) {
                csk = cxgbi_check_route(dst_addr);
#if IS_ENABLED(CONFIG_IPV6)
        } else if (dst_addr->sa_family == AF_INET6) {
                csk = cxgbi_check_route6(dst_addr);
#endif
        } else {
                pr_info("address family 0x%x NOT supported.\n",
                        dst_addr->sa_family);
                err = -EAFNOSUPPORT;
                return (struct iscsi_endpoint *)ERR_PTR(err);
        }

        if (IS_ERR(csk))
                return (struct iscsi_endpoint *)csk;
        cxgbi_sock_get(csk);

        if (!hba)
                hba = csk->cdev->hbas[csk->port_id];
        else if (hba != csk->cdev->hbas[csk->port_id]) {
                pr_info("Could not connect through requested host %u"
                        "hba 0x%p != 0x%p (%u).\n",
                        shost->host_no, hba,
                        csk->cdev->hbas[csk->port_id], csk->port_id);
                err = -ENOSPC;
                goto release_conn;
        }

        err = sock_get_port(csk);
        if (err)
                goto release_conn;

        cxgbi_sock_set_state(csk, CTP_CONNECTING);
        err = csk->cdev->csk_init_act_open(csk);
        if (err)
                goto release_conn;

        if (cxgbi_sock_is_closing(csk)) {
                err = -ENOSPC;
                pr_info("csk 0x%p is closing.\n", csk);
                goto release_conn;
        }

        ep = iscsi_create_endpoint(sizeof(*cep));
        if (!ep) {
                err = -ENOMEM;
                pr_info("iscsi alloc ep, OOM.\n");
                goto release_conn;
        }

        cep = ep->dd_data;
        cep->csk = csk;
        cep->chba = hba;

        log_debug(1 << CXGBI_DBG_ISCSI | 1 << CXGBI_DBG_SOCK,
                "ep 0x%p, cep 0x%p, csk 0x%p, hba 0x%p,%s.\n",
                ep, cep, csk, hba, hba->ndev->name);
        return ep;

release_conn:
        cxgbi_sock_put(csk);
        cxgbi_sock_closed(csk);
err_out:
        return ERR_PTR(err);
}
EXPORT_SYMBOL_GPL(cxgbi_ep_connect);

int cxgbi_ep_poll(struct iscsi_endpoint *ep, int timeout_ms)
{
        struct cxgbi_endpoint *cep = ep->dd_data;
        struct cxgbi_sock *csk = cep->csk;

        if (!cxgbi_sock_is_established(csk))
                return 0;
        return 1;
}
EXPORT_SYMBOL_GPL(cxgbi_ep_poll);

void cxgbi_ep_disconnect(struct iscsi_endpoint *ep)
{
        struct cxgbi_endpoint *cep = ep->dd_data;
        struct cxgbi_conn *cconn = cep->cconn;
        struct cxgbi_sock *csk = cep->csk;

        log_debug(1 << CXGBI_DBG_ISCSI | 1 << CXGBI_DBG_SOCK,
                "ep 0x%p, cep 0x%p, cconn 0x%p, csk 0x%p,%u,0x%lx.\n",
                ep, cep, cconn, csk, csk->state, csk->flags);

        if (cconn && cconn->iconn) {
                iscsi_suspend_tx(cconn->iconn);
                write_lock_bh(&csk->callback_lock);
                cep->csk->user_data = NULL;
                cconn->cep = NULL;
                write_unlock_bh(&csk->callback_lock);
        }
        iscsi_destroy_endpoint(ep);

        if (likely(csk->state >= CTP_ESTABLISHED))
                need_active_close(csk);
        else
                cxgbi_sock_closed(csk);

        cxgbi_sock_put(csk);
}
EXPORT_SYMBOL_GPL(cxgbi_ep_disconnect);

int cxgbi_iscsi_init(struct iscsi_transport *itp,
                        struct scsi_transport_template **stt)
{
        *stt = iscsi_register_transport(itp);
        if (*stt == NULL) {
                pr_err("unable to register %s transport 0x%p.\n",
                        itp->name, itp);
                return -ENODEV;
        }
        log_debug(1 << CXGBI_DBG_ISCSI,
                "%s, registered iscsi transport 0x%p.\n",
                itp->name, stt);
        return 0;
}
EXPORT_SYMBOL_GPL(cxgbi_iscsi_init);

void cxgbi_iscsi_cleanup(struct iscsi_transport *itp,
                        struct scsi_transport_template **stt)
{
        if (*stt) {
                log_debug(1 << CXGBI_DBG_ISCSI,
                        "de-register transport 0x%p, %s, stt 0x%p.\n",
                        itp, itp->name, *stt);
                *stt = NULL;
                iscsi_unregister_transport(itp);
        }
}
EXPORT_SYMBOL_GPL(cxgbi_iscsi_cleanup);

umode_t cxgbi_attr_is_visible(int param_type, int param)
{
        switch (param_type) {
        case ISCSI_HOST_PARAM:
                switch (param) {
                case ISCSI_HOST_PARAM_NETDEV_NAME:
                case ISCSI_HOST_PARAM_HWADDRESS:
                case ISCSI_HOST_PARAM_IPADDRESS:
                case ISCSI_HOST_PARAM_INITIATOR_NAME:
                        return S_IRUGO;
                default:
                        return 0;
                }
        case ISCSI_PARAM:
                switch (param) {
                case ISCSI_PARAM_MAX_RECV_DLENGTH:
                case ISCSI_PARAM_MAX_XMIT_DLENGTH:
                case ISCSI_PARAM_HDRDGST_EN:
                case ISCSI_PARAM_DATADGST_EN:
                case ISCSI_PARAM_CONN_ADDRESS:
                case ISCSI_PARAM_CONN_PORT:
                case ISCSI_PARAM_EXP_STATSN:
                case ISCSI_PARAM_PERSISTENT_ADDRESS:
                case ISCSI_PARAM_PERSISTENT_PORT:
                case ISCSI_PARAM_PING_TMO:
                case ISCSI_PARAM_RECV_TMO:
                case ISCSI_PARAM_INITIAL_R2T_EN:
                case ISCSI_PARAM_MAX_R2T:
                case ISCSI_PARAM_IMM_DATA_EN:
                case ISCSI_PARAM_FIRST_BURST:
                case ISCSI_PARAM_MAX_BURST:
                case ISCSI_PARAM_PDU_INORDER_EN:
                case ISCSI_PARAM_DATASEQ_INORDER_EN:
                case ISCSI_PARAM_ERL:
                case ISCSI_PARAM_TARGET_NAME:
                case ISCSI_PARAM_TPGT:
                case ISCSI_PARAM_USERNAME:
                case ISCSI_PARAM_PASSWORD:
                case ISCSI_PARAM_USERNAME_IN:
                case ISCSI_PARAM_PASSWORD_IN:
                case ISCSI_PARAM_FAST_ABORT:
                case ISCSI_PARAM_ABORT_TMO:
                case ISCSI_PARAM_LU_RESET_TMO:
                case ISCSI_PARAM_TGT_RESET_TMO:
                case ISCSI_PARAM_IFACE_NAME:
                case ISCSI_PARAM_INITIATOR_NAME:
                        return S_IRUGO;
                default:
                        return 0;
                }
        }

        return 0;
}
EXPORT_SYMBOL_GPL(cxgbi_attr_is_visible);

static int __init libcxgbi_init_module(void)
{
        sw_tag_idx_bits = (__ilog2_u32(ISCSI_ITT_MASK)) + 1;
        sw_tag_age_bits = (__ilog2_u32(ISCSI_AGE_MASK)) + 1;

        pr_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);

        ddp_setup_host_page_size();
        return 0;
}

static void __exit libcxgbi_exit_module(void)
{
        cxgbi_device_unregister_all(0xFF);
        return;
}

module_init(libcxgbi_init_module);
module_exit(libcxgbi_exit_module);