[SCSI] fcoe: move offload exchange manager pointer from fcoe_port to fcoe_interface

[safe/jmp/linux-2.6] / drivers / scsi / fcoe / fcoe.c

/*
 * Copyright(c) 2007 - 2009 Intel Corporation. All rights reserved.
 *
 * This program is free software; you can redistribute it and/or modify it
 * under the terms and conditions of the GNU General Public License,
 * version 2, as published by the Free Software Foundation.
 *
 * This program is distributed in the hope it will be useful, but WITHOUT
 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
 * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License for
 * more details.
 *
 * You should have received a copy of the GNU General Public License along with
 * this program; if not, write to the Free Software Foundation, Inc.,
 * 51 Franklin St - Fifth Floor, Boston, MA 02110-1301 USA.
 *
 * Maintained at www.Open-FCoE.org
 */

#include <linux/module.h>
#include <linux/version.h>
#include <linux/spinlock.h>
#include <linux/netdevice.h>
#include <linux/etherdevice.h>
#include <linux/ethtool.h>
#include <linux/if_ether.h>
#include <linux/if_vlan.h>
#include <linux/crc32.h>
#include <linux/cpu.h>
#include <linux/fs.h>
#include <linux/sysfs.h>
#include <linux/ctype.h>
#include <scsi/scsi_tcq.h>
#include <scsi/scsicam.h>
#include <scsi/scsi_transport.h>
#include <scsi/scsi_transport_fc.h>
#include <net/rtnetlink.h>

#include <scsi/fc/fc_encaps.h>
#include <scsi/fc/fc_fip.h>

#include <scsi/libfc.h>
#include <scsi/fc_frame.h>
#include <scsi/libfcoe.h>

#include "fcoe.h"

MODULE_AUTHOR("Open-FCoE.org");
MODULE_DESCRIPTION("FCoE");
MODULE_LICENSE("GPL v2");

/* Performance tuning parameters for fcoe */
static unsigned int fcoe_ddp_min;
module_param_named(ddp_min, fcoe_ddp_min, uint, S_IRUGO | S_IWUSR);
MODULE_PARM_DESC(ddp_min, "Minimum I/O size in bytes for "      \
                 "Direct Data Placement (DDP).");

/* fcoe host list */
LIST_HEAD(fcoe_hostlist);
DEFINE_RWLOCK(fcoe_hostlist_lock);
DEFINE_PER_CPU(struct fcoe_percpu_s, fcoe_percpu);

/* Function Prototypes */
static int fcoe_reset(struct Scsi_Host *shost);
static int fcoe_xmit(struct fc_lport *, struct fc_frame *);
static int fcoe_rcv(struct sk_buff *, struct net_device *,
                    struct packet_type *, struct net_device *);
static int fcoe_percpu_receive_thread(void *arg);
static void fcoe_clean_pending_queue(struct fc_lport *lp);
static void fcoe_percpu_clean(struct fc_lport *lp);
static int fcoe_link_ok(struct fc_lport *lp);

static struct fc_lport *fcoe_hostlist_lookup(const struct net_device *);
static int fcoe_hostlist_add(const struct fc_lport *);
static int fcoe_hostlist_remove(const struct fc_lport *);

static void fcoe_check_wait_queue(struct fc_lport *, struct sk_buff *);
static int fcoe_device_notification(struct notifier_block *, ulong, void *);
static void fcoe_dev_setup(void);
static void fcoe_dev_cleanup(void);

/* notification function from net device */
static struct notifier_block fcoe_notifier = {
        .notifier_call = fcoe_device_notification,
};

static struct scsi_transport_template *scsi_transport_fcoe_sw;

struct fc_function_template fcoe_transport_function = {
        .show_host_node_name = 1,
        .show_host_port_name = 1,
        .show_host_supported_classes = 1,
        .show_host_supported_fc4s = 1,
        .show_host_active_fc4s = 1,
        .show_host_maxframe_size = 1,

        .show_host_port_id = 1,
        .show_host_supported_speeds = 1,
        .get_host_speed = fc_get_host_speed,
        .show_host_speed = 1,
        .show_host_port_type = 1,
        .get_host_port_state = fc_get_host_port_state,
        .show_host_port_state = 1,
        .show_host_symbolic_name = 1,

        .dd_fcrport_size = sizeof(struct fc_rport_libfc_priv),
        .show_rport_maxframe_size = 1,
        .show_rport_supported_classes = 1,

        .show_host_fabric_name = 1,
        .show_starget_node_name = 1,
        .show_starget_port_name = 1,
        .show_starget_port_id = 1,
        .set_rport_dev_loss_tmo = fc_set_rport_loss_tmo,
        .show_rport_dev_loss_tmo = 1,
        .get_fc_host_stats = fc_get_host_stats,
        .issue_fc_host_lip = fcoe_reset,

        .terminate_rport_io = fc_rport_terminate_io,
};

static struct scsi_host_template fcoe_shost_template = {
        .module = THIS_MODULE,
        .name = "FCoE Driver",
        .proc_name = FCOE_NAME,
        .queuecommand = fc_queuecommand,
        .eh_abort_handler = fc_eh_abort,
        .eh_device_reset_handler = fc_eh_device_reset,
        .eh_host_reset_handler = fc_eh_host_reset,
        .slave_alloc = fc_slave_alloc,
        .change_queue_depth = fc_change_queue_depth,
        .change_queue_type = fc_change_queue_type,
        .this_id = -1,
        .cmd_per_lun = 32,
        .can_queue = FCOE_MAX_OUTSTANDING_COMMANDS,
        .use_clustering = ENABLE_CLUSTERING,
        .sg_tablesize = SG_ALL,
        .max_sectors = 0xffff,
};

/**
 * fcoe_fip_recv - handle a received FIP frame.
 * @skb: the receive skb
 * @dev: associated &net_device
 * @ptype: the &packet_type structure which was used to register this handler.
 * @orig_dev: original receive &net_device, in case @dev is a bond.
 *
 * Returns: 0 for success
 */
static int fcoe_fip_recv(struct sk_buff *skb, struct net_device *dev,
                         struct packet_type *ptype,
                         struct net_device *orig_dev)
{
        struct fcoe_interface *fcoe;

        fcoe = container_of(ptype, struct fcoe_interface, fip_packet_type);
        fcoe_ctlr_recv(&fcoe->ctlr, skb);
        return 0;
}

/**
 * fcoe_fip_send() - send an Ethernet-encapsulated FIP frame.
 * @fip: FCoE controller.
 * @skb: FIP Packet.
 */
static void fcoe_fip_send(struct fcoe_ctlr *fip, struct sk_buff *skb)
{
        skb->dev = fcoe_from_ctlr(fip)->netdev;
        dev_queue_xmit(skb);
}

/**
 * fcoe_update_src_mac() - Update Ethernet MAC filters.
 * @fip: FCoE controller.
 * @old: Unicast MAC address to delete if the MAC is non-zero.
 * @new: Unicast MAC address to add.
 *
 * Remove any previously-set unicast MAC filter.
 * Add secondary FCoE MAC address filter for our OUI.
 */
static void fcoe_update_src_mac(struct fcoe_ctlr *fip, u8 *old, u8 *new)
{
        struct fcoe_interface *fcoe;

        fcoe = fcoe_from_ctlr(fip);
        rtnl_lock();
        if (!is_zero_ether_addr(old))
                dev_unicast_delete(fcoe->netdev, old);
        dev_unicast_add(fcoe->netdev, new);
        rtnl_unlock();
}

/**
 * fcoe_lport_config() - sets up the fc_lport
 * @lp: ptr to the fc_lport
 *
 * Returns: 0 for success
 */
static int fcoe_lport_config(struct fc_lport *lp)
{
        lp->link_up = 0;
        lp->qfull = 0;
        lp->max_retry_count = 3;
        lp->max_rport_retry_count = 3;
        lp->e_d_tov = 2 * 1000; /* FC-FS default */
        lp->r_a_tov = 2 * 2 * 1000;
        lp->service_params = (FCP_SPPF_INIT_FCN | FCP_SPPF_RD_XRDY_DIS |
                              FCP_SPPF_RETRY | FCP_SPPF_CONF_COMPL);

        fc_lport_init_stats(lp);

        /* lport fc_lport related configuration */
        fc_lport_config(lp);

        /* offload related configuration */
        lp->crc_offload = 0;
        lp->seq_offload = 0;
        lp->lro_enabled = 0;
        lp->lro_xid = 0;
        lp->lso_max = 0;

        return 0;
}

/**
 * fcoe_netdev_cleanup() - clean up netdev configurations
 * @port: ptr to the fcoe_port
 */
void fcoe_netdev_cleanup(struct fcoe_port *port)
{
        u8 flogi_maddr[ETH_ALEN];
        struct fcoe_interface *fcoe = port->fcoe;

        /* Don't listen for Ethernet packets anymore */
        dev_remove_pack(&fcoe->fcoe_packet_type);
        dev_remove_pack(&fcoe->fip_packet_type);

        /* Delete secondary MAC addresses */
        rtnl_lock();
        memcpy(flogi_maddr, (u8[6]) FC_FCOE_FLOGI_MAC, ETH_ALEN);
        dev_unicast_delete(fcoe->netdev, flogi_maddr);
        if (!is_zero_ether_addr(fcoe->ctlr.data_src_addr))
                dev_unicast_delete(fcoe->netdev, fcoe->ctlr.data_src_addr);
        if (fcoe->ctlr.spma)
                dev_unicast_delete(fcoe->netdev, fcoe->ctlr.ctl_src_addr);
        dev_mc_delete(fcoe->netdev, FIP_ALL_ENODE_MACS, ETH_ALEN, 0);
        rtnl_unlock();
}

/**
 * fcoe_queue_timer() - fcoe queue timer
 * @lp: the fc_lport pointer
 *
 * Calls fcoe_check_wait_queue on timeout
 *
 */
static void fcoe_queue_timer(ulong lp)
{
        fcoe_check_wait_queue((struct fc_lport *)lp, NULL);
}

/**
 * fcoe_netdev_config() - Set up netdev for SW FCoE
 * @lp : ptr to the fc_lport
 * @netdev : ptr to the associated netdevice struct
 *
 * Must be called after fcoe_lport_config() as it will use lport mutex
 *
 * Returns : 0 for success
 */
static int fcoe_netdev_config(struct fc_lport *lp, struct net_device *netdev)
{
        u32 mfs;
        u64 wwnn, wwpn;
        struct fcoe_interface *fcoe;
        struct fcoe_port *port;
        u8 flogi_maddr[ETH_ALEN];
        struct netdev_hw_addr *ha;

        /* Setup lport private data to point to fcoe softc */
        port = lport_priv(lp);
        fcoe = port->fcoe;
        fcoe->ctlr.lp = lp;
        fcoe->netdev = netdev;

        /* Do not support for bonding device */
        if ((netdev->priv_flags & IFF_MASTER_ALB) ||
            (netdev->priv_flags & IFF_SLAVE_INACTIVE) ||
            (netdev->priv_flags & IFF_MASTER_8023AD)) {
                return -EOPNOTSUPP;
        }

        /*
         * Determine max frame size based on underlying device and optional
         * user-configured limit.  If the MFS is too low, fcoe_link_ok()
         * will return 0, so do this first.
         */
        mfs = netdev->mtu - (sizeof(struct fcoe_hdr) +
                             sizeof(struct fcoe_crc_eof));
        if (fc_set_mfs(lp, mfs))
                return -EINVAL;

        /* offload features support */
        if (netdev->features & NETIF_F_SG)
                lp->sg_supp = 1;

        if (netdev->features & NETIF_F_FCOE_CRC) {
                lp->crc_offload = 1;
                FCOE_NETDEV_DBG(netdev, "Supports FCCRC offload\n");
        }
        if (netdev->features & NETIF_F_FSO) {
                lp->seq_offload = 1;
                lp->lso_max = netdev->gso_max_size;
                FCOE_NETDEV_DBG(netdev, "Supports LSO for max len 0x%x\n",
                                lp->lso_max);
        }
        if (netdev->fcoe_ddp_xid) {
                lp->lro_enabled = 1;
                lp->lro_xid = netdev->fcoe_ddp_xid;
                FCOE_NETDEV_DBG(netdev, "Supports LRO for max xid 0x%x\n",
                                lp->lro_xid);
        }
        skb_queue_head_init(&port->fcoe_pending_queue);
        port->fcoe_pending_queue_active = 0;
        setup_timer(&port->timer, fcoe_queue_timer, (unsigned long)lp);

        /* look for SAN MAC address, if multiple SAN MACs exist, only
         * use the first one for SPMA */
        rcu_read_lock();
        for_each_dev_addr(netdev, ha) {
                if ((ha->type == NETDEV_HW_ADDR_T_SAN) &&
                    (is_valid_ether_addr(fcoe->ctlr.ctl_src_addr))) {
                        memcpy(fcoe->ctlr.ctl_src_addr, ha->addr, ETH_ALEN);
                        fcoe->ctlr.spma = 1;
                        break;
                }
        }
        rcu_read_unlock();

        /* setup Source Mac Address */
        if (!fcoe->ctlr.spma)
                memcpy(fcoe->ctlr.ctl_src_addr, netdev->dev_addr,
                       netdev->addr_len);

        wwnn = fcoe_wwn_from_mac(netdev->dev_addr, 1, 0);
        fc_set_wwnn(lp, wwnn);
        /* XXX - 3rd arg needs to be vlan id */
        wwpn = fcoe_wwn_from_mac(netdev->dev_addr, 2, 0);
        fc_set_wwpn(lp, wwpn);

        /*
         * Add FCoE MAC address as second unicast MAC address
         * or enter promiscuous mode if not capable of listening
         * for multiple unicast MACs.
         */
        rtnl_lock();
        memcpy(flogi_maddr, (u8[6]) FC_FCOE_FLOGI_MAC, ETH_ALEN);
        dev_unicast_add(netdev, flogi_maddr);
        if (fcoe->ctlr.spma)
                dev_unicast_add(netdev, fcoe->ctlr.ctl_src_addr);
        dev_mc_add(netdev, FIP_ALL_ENODE_MACS, ETH_ALEN, 0);
        rtnl_unlock();

        /*
         * setup the receive function from ethernet driver
         * on the ethertype for the given device
         */
        fcoe->fcoe_packet_type.func = fcoe_rcv;
        fcoe->fcoe_packet_type.type = __constant_htons(ETH_P_FCOE);
        fcoe->fcoe_packet_type.dev = netdev;
        dev_add_pack(&fcoe->fcoe_packet_type);

        fcoe->fip_packet_type.func = fcoe_fip_recv;
        fcoe->fip_packet_type.type = htons(ETH_P_FIP);
        fcoe->fip_packet_type.dev = netdev;
        dev_add_pack(&fcoe->fip_packet_type);

        return 0;
}

/**
 * fcoe_shost_config() - Sets up fc_lport->host
 * @lp : ptr to the fc_lport
 * @shost : ptr to the associated scsi host
 * @dev : device associated to scsi host
 *
 * Must be called after fcoe_lport_config() and fcoe_netdev_config()
 *
 * Returns : 0 for success
 */
static int fcoe_shost_config(struct fc_lport *lp, struct Scsi_Host *shost,
                                struct device *dev)
{
        int rc = 0;

        /* lport scsi host config */
        lp->host = shost;

        lp->host->max_lun = FCOE_MAX_LUN;
        lp->host->max_id = FCOE_MAX_FCP_TARGET;
        lp->host->max_channel = 0;
        lp->host->transportt = scsi_transport_fcoe_sw;

        /* add the new host to the SCSI-ml */
        rc = scsi_add_host(lp->host, dev);
        if (rc) {
                FCOE_NETDEV_DBG(fcoe_netdev(lp), "fcoe_shost_config: "
                                "error on scsi_add_host\n");
                return rc;
        }
        sprintf(fc_host_symbolic_name(lp->host), "%s v%s over %s",
                FCOE_NAME, FCOE_VERSION,
                fcoe_netdev(lp)->name);

        return 0;
}

/*
 * fcoe_oem_match() - match for read types IO
 * @fp: the fc_frame for new IO.
 *
 * Returns : true for read types IO, otherwise returns false.
 */
bool fcoe_oem_match(struct fc_frame *fp)
{
        return fc_fcp_is_read(fr_fsp(fp)) &&
                (fr_fsp(fp)->data_len > fcoe_ddp_min);
}

/**
 * fcoe_em_config() - allocates em for this lport
 * @lp: the fcoe that em is to allocated for
 *
 * Called with write fcoe_hostlist_lock held.
 *
 * Returns : 0 on success
 */
static inline int fcoe_em_config(struct fc_lport *lp)
{
        struct fcoe_port *port = lport_priv(lp);
        struct fcoe_interface *fcoe = port->fcoe;
        struct fcoe_interface *oldfcoe = NULL;
        struct net_device *old_real_dev, *cur_real_dev;
        u16 min_xid = FCOE_MIN_XID;
        u16 max_xid = FCOE_MAX_XID;

        /*
         * Check if need to allocate an em instance for
         * offload exchange ids to be shared across all VN_PORTs/lport.
         */
        if (!lp->lro_enabled || !lp->lro_xid || (lp->lro_xid >= max_xid)) {
                lp->lro_xid = 0;
                goto skip_oem;
        }

        /*
         * Reuse existing offload em instance in case
         * it is already allocated on real eth device
         */
        if (fcoe->netdev->priv_flags & IFF_802_1Q_VLAN)
                cur_real_dev = vlan_dev_real_dev(fcoe->netdev);
        else
                cur_real_dev = fcoe->netdev;

        list_for_each_entry(oldfcoe, &fcoe_hostlist, list) {
                if (oldfcoe->netdev->priv_flags & IFF_802_1Q_VLAN)
                        old_real_dev = vlan_dev_real_dev(oldfcoe->netdev);
                else
                        old_real_dev = oldfcoe->netdev;

                if (cur_real_dev == old_real_dev) {
                        fcoe->oem = oldfcoe->oem;
                        break;
                }
        }

        if (fcoe->oem) {
                if (!fc_exch_mgr_add(lp, fcoe->oem, fcoe_oem_match)) {
                        printk(KERN_ERR "fcoe_em_config: failed to add "
                               "offload em:%p on interface:%s\n",
                               fcoe->oem, fcoe->netdev->name);
                        return -ENOMEM;
                }
        } else {
                fcoe->oem = fc_exch_mgr_alloc(lp, FC_CLASS_3,
                                            FCOE_MIN_XID, lp->lro_xid,
                                            fcoe_oem_match);
                if (!fcoe->oem) {
                        printk(KERN_ERR "fcoe_em_config: failed to allocate "
                               "em for offload exches on interface:%s\n",
                               fcoe->netdev->name);
                        return -ENOMEM;
                }
        }

        /*
         * Exclude offload EM xid range from next EM xid range.
         */
        min_xid += lp->lro_xid + 1;

skip_oem:
        if (!fc_exch_mgr_alloc(lp, FC_CLASS_3, min_xid, max_xid, NULL)) {
                printk(KERN_ERR "fcoe_em_config: failed to "
                       "allocate em on interface %s\n", fcoe->netdev->name);
                return -ENOMEM;
        }

        return 0;
}

/**
 * fcoe_if_destroy() - FCoE software HBA tear-down function
 * @lport: fc_lport to destroy
 */
static void fcoe_if_destroy(struct fc_lport *lport)
{
        struct fcoe_port *port = lport_priv(lport);
        struct fcoe_interface *fcoe = port->fcoe;
        struct net_device *netdev = fcoe->netdev;

        FCOE_NETDEV_DBG(netdev, "Destroying interface\n");

        /* Logout of the fabric */
        fc_fabric_logoff(lport);

        /* Remove the instance from fcoe's list */
        fcoe_hostlist_remove(lport);

        /* clean up netdev configurations */
        fcoe_netdev_cleanup(port);

        /* tear-down the FCoE controller */
        fcoe_ctlr_destroy(&fcoe->ctlr);

        /* Free queued packets for the per-CPU receive threads */
        fcoe_percpu_clean(lport);

        /* Cleanup the fc_lport */
        fc_lport_destroy(lport);
        fc_fcp_destroy(lport);

        /* Detach from the scsi-ml */
        fc_remove_host(lport->host);
        scsi_remove_host(lport->host);

        /* There are no more rports or I/O, free the EM */
        fc_exch_mgr_free(lport);

        /* Free existing skbs */
        fcoe_clean_pending_queue(lport);

        /* Stop the timer */
        del_timer_sync(&port->timer);

        /* Free memory used by statistical counters */
        fc_lport_free_stats(lport);

        /* Release the net_device and Scsi_Host */
        dev_put(netdev);
        scsi_host_put(lport->host);
        kfree(fcoe);            /* TODO, should be refcounted */
}

/*
 * fcoe_ddp_setup - calls LLD's ddp_setup through net_device
 * @lp: the corresponding fc_lport
 * @xid: the exchange id for this ddp transfer
 * @sgl: the scatterlist describing this transfer
 * @sgc: number of sg items
 *
 * Returns : 0 no ddp
 */
static int fcoe_ddp_setup(struct fc_lport *lp, u16 xid,
                             struct scatterlist *sgl, unsigned int sgc)
{
        struct net_device *n = fcoe_netdev(lp);

        if (n->netdev_ops && n->netdev_ops->ndo_fcoe_ddp_setup)
                return n->netdev_ops->ndo_fcoe_ddp_setup(n, xid, sgl, sgc);

        return 0;
}

/*
 * fcoe_ddp_done - calls LLD's ddp_done through net_device
 * @lp: the corresponding fc_lport
 * @xid: the exchange id for this ddp transfer
 *
 * Returns : the length of data that have been completed by ddp
 */
static int fcoe_ddp_done(struct fc_lport *lp, u16 xid)
{
        struct net_device *n = fcoe_netdev(lp);

        if (n->netdev_ops && n->netdev_ops->ndo_fcoe_ddp_done)
                return n->netdev_ops->ndo_fcoe_ddp_done(n, xid);
        return 0;
}

static struct libfc_function_template fcoe_libfc_fcn_templ = {
        .frame_send = fcoe_xmit,
        .ddp_setup = fcoe_ddp_setup,
        .ddp_done = fcoe_ddp_done,
};

/**
 * fcoe_if_create() - this function creates the fcoe interface
 * @netdev: pointer the associated netdevice
 * @parent: device pointer to be the parent in sysfs for the SCSI host
 *
 * Creates fc_lport struct and scsi_host for lport, configures lport
 * and starts fabric login.
 *
 * Returns : The allocated fc_lport or an error pointer
 */
static struct fc_lport *fcoe_if_create(struct net_device *netdev,
                                       struct device *parent)
{
        int rc;
        struct fc_lport *lport = NULL;
        struct fcoe_port *port;
        struct fcoe_interface *fcoe;
        struct Scsi_Host *shost;

        FCOE_NETDEV_DBG(netdev, "Create Interface\n");

        fcoe = kzalloc(sizeof(*fcoe), GFP_KERNEL);
        if (!fcoe) {
                FCOE_NETDEV_DBG(netdev, "Could not allocate fcoe structure\n");
                rc = -ENOMEM;
                goto out;
        }

        shost = libfc_host_alloc(&fcoe_shost_template,
                                 sizeof(struct fcoe_port));
        if (!shost) {
                FCOE_NETDEV_DBG(netdev, "Could not allocate host structure\n");
                rc = -ENOMEM;
                goto out_kfree_port;
        }
        lport = shost_priv(shost);
        port = lport_priv(lport);

        port->fcoe = fcoe;
        fcoe->priv = port;

        /* configure fc_lport, e.g., em */
        rc = fcoe_lport_config(lport);
        if (rc) {
                FCOE_NETDEV_DBG(netdev, "Could not configure lport for the "
                                "interface\n");
                goto out_host_put;
        }

        /*
         * Initialize FIP.
         */
        fcoe_ctlr_init(&fcoe->ctlr);
        fcoe->ctlr.send = fcoe_fip_send;
        fcoe->ctlr.update_mac = fcoe_update_src_mac;

        /* configure lport network properties */
        rc = fcoe_netdev_config(lport, netdev);
        if (rc) {
                FCOE_NETDEV_DBG(netdev, "Could not configure netdev for the "
                                "interface\n");
                goto out_netdev_cleanup;
        }

        /* configure lport scsi host properties */
        rc = fcoe_shost_config(lport, shost, parent);
        if (rc) {
                FCOE_NETDEV_DBG(netdev, "Could not configure shost for the "
                                "interface\n");
                goto out_netdev_cleanup;
        }

        /* Initialize the library */
        rc = fcoe_libfc_config(lport, &fcoe_libfc_fcn_templ);
        if (rc) {
                FCOE_NETDEV_DBG(netdev, "Could not configure libfc for the "
                                "interface\n");
                goto out_lp_destroy;
        }

        /*
         * fcoe_em_alloc() and fcoe_hostlist_add() both
         * need to be atomic under fcoe_hostlist_lock
         * since fcoe_em_alloc() looks for an existing EM
         * instance on host list updated by fcoe_hostlist_add().
         */
        write_lock(&fcoe_hostlist_lock);
        /* lport exch manager allocation */
        rc = fcoe_em_config(lport);
        if (rc) {
                FCOE_NETDEV_DBG(netdev, "Could not configure the EM for the "
                                "interface\n");
                goto out_lp_destroy;
        }

        /* add to lports list */
        fcoe_hostlist_add(lport);
        write_unlock(&fcoe_hostlist_lock);

        lport->boot_time = jiffies;

        fc_fabric_login(lport);

        if (!fcoe_link_ok(lport))
                fcoe_ctlr_link_up(&fcoe->ctlr);

        dev_hold(netdev);

        return lport;

out_lp_destroy:
        fc_exch_mgr_free(lport);
out_netdev_cleanup:
        fcoe_netdev_cleanup(port);
out_host_put:
        scsi_host_put(lport->host);
out_kfree_port:
        kfree(fcoe);
out:
        return ERR_PTR(rc);
}

/**
 * fcoe_if_init() - attach to scsi transport
 *
 * Returns : 0 on success
 */
static int __init fcoe_if_init(void)
{
        /* attach to scsi transport */
        scsi_transport_fcoe_sw =
                fc_attach_transport(&fcoe_transport_function);

        if (!scsi_transport_fcoe_sw) {
                printk(KERN_ERR "fcoe: Failed to attach to the FC transport\n");
                return -ENODEV;
        }

        return 0;
}

/**
 * fcoe_if_exit() - detach from scsi transport
 *
 * Returns : 0 on success
 */
int __exit fcoe_if_exit(void)
{
        fc_release_transport(scsi_transport_fcoe_sw);
        return 0;
}

/**
 * fcoe_percpu_thread_create() - Create a receive thread for an online cpu
 * @cpu: cpu index for the online cpu
 */
static void fcoe_percpu_thread_create(unsigned int cpu)
{
        struct fcoe_percpu_s *p;
        struct task_struct *thread;

        p = &per_cpu(fcoe_percpu, cpu);

        thread = kthread_create(fcoe_percpu_receive_thread,
                                (void *)p, "fcoethread/%d", cpu);

        if (likely(!IS_ERR(p->thread))) {
                kthread_bind(thread, cpu);
                wake_up_process(thread);

                spin_lock_bh(&p->fcoe_rx_list.lock);
                p->thread = thread;
                spin_unlock_bh(&p->fcoe_rx_list.lock);
        }
}

/**
 * fcoe_percpu_thread_destroy() - removes the rx thread for the given cpu
 * @cpu: cpu index the rx thread is to be removed
 *
 * Destroys a per-CPU Rx thread. Any pending skbs are moved to the
 * current CPU's Rx thread. If the thread being destroyed is bound to
 * the CPU processing this context the skbs will be freed.
 */
static void fcoe_percpu_thread_destroy(unsigned int cpu)
{
        struct fcoe_percpu_s *p;
        struct task_struct *thread;
        struct page *crc_eof;
        struct sk_buff *skb;
#ifdef CONFIG_SMP
        struct fcoe_percpu_s *p0;
        unsigned targ_cpu = smp_processor_id();
#endif /* CONFIG_SMP */

        FCOE_DBG("Destroying receive thread for CPU %d\n", cpu);

        /* Prevent any new skbs from being queued for this CPU. */
        p = &per_cpu(fcoe_percpu, cpu);
        spin_lock_bh(&p->fcoe_rx_list.lock);
        thread = p->thread;
        p->thread = NULL;
        crc_eof = p->crc_eof_page;
        p->crc_eof_page = NULL;
        p->crc_eof_offset = 0;
        spin_unlock_bh(&p->fcoe_rx_list.lock);

#ifdef CONFIG_SMP
        /*
         * Don't bother moving the skb's if this context is running
         * on the same CPU that is having its thread destroyed. This
         * can easily happen when the module is removed.
         */
        if (cpu != targ_cpu) {
                p0 = &per_cpu(fcoe_percpu, targ_cpu);
                spin_lock_bh(&p0->fcoe_rx_list.lock);
                if (p0->thread) {
                        FCOE_DBG("Moving frames from CPU %d to CPU %d\n",
                                 cpu, targ_cpu);

                        while ((skb = __skb_dequeue(&p->fcoe_rx_list)) != NULL)
                                __skb_queue_tail(&p0->fcoe_rx_list, skb);
                        spin_unlock_bh(&p0->fcoe_rx_list.lock);
                } else {
                        /*
                         * The targeted CPU is not initialized and cannot accept
                         * new  skbs. Unlock the targeted CPU and drop the skbs
                         * on the CPU that is going offline.
                         */
                        while ((skb = __skb_dequeue(&p->fcoe_rx_list)) != NULL)
                                kfree_skb(skb);
                        spin_unlock_bh(&p0->fcoe_rx_list.lock);
                }
        } else {
                /*
                 * This scenario occurs when the module is being removed
                 * and all threads are being destroyed. skbs will continue
                 * to be shifted from the CPU thread that is being removed
                 * to the CPU thread associated with the CPU that is processing
                 * the module removal. Once there is only one CPU Rx thread it
                 * will reach this case and we will drop all skbs and later
                 * stop the thread.
                 */
                spin_lock_bh(&p->fcoe_rx_list.lock);
                while ((skb = __skb_dequeue(&p->fcoe_rx_list)) != NULL)
                        kfree_skb(skb);
                spin_unlock_bh(&p->fcoe_rx_list.lock);
        }
#else
        /*
         * This a non-SMP scenario where the singular Rx thread is
         * being removed. Free all skbs and stop the thread.
         */
        spin_lock_bh(&p->fcoe_rx_list.lock);
        while ((skb = __skb_dequeue(&p->fcoe_rx_list)) != NULL)
                kfree_skb(skb);
        spin_unlock_bh(&p->fcoe_rx_list.lock);
#endif

        if (thread)
                kthread_stop(thread);

        if (crc_eof)
                put_page(crc_eof);
}

/**
 * fcoe_cpu_callback() - fcoe cpu hotplug event callback
 * @nfb: callback data block
 * @action: event triggering the callback
 * @hcpu: index for the cpu of this event
 *
 * This creates or destroys per cpu data for fcoe
 *
 * Returns NOTIFY_OK always.
 */
static int fcoe_cpu_callback(struct notifier_block *nfb,
                             unsigned long action, void *hcpu)
{
        unsigned cpu = (unsigned long)hcpu;

        switch (action) {
        case CPU_ONLINE:
        case CPU_ONLINE_FROZEN:
                FCOE_DBG("CPU %x online: Create Rx thread\n", cpu);
                fcoe_percpu_thread_create(cpu);
                break;
        case CPU_DEAD:
        case CPU_DEAD_FROZEN:
                FCOE_DBG("CPU %x offline: Remove Rx thread\n", cpu);
                fcoe_percpu_thread_destroy(cpu);
                break;
        default:
                break;
        }
        return NOTIFY_OK;
}

static struct notifier_block fcoe_cpu_notifier = {
        .notifier_call = fcoe_cpu_callback,
};

/**
 * fcoe_rcv() - this is the fcoe receive function called by NET_RX_SOFTIRQ
 * @skb: the receive skb
 * @dev: associated net device
 * @ptype: context
 * @olddev: last device
 *
 * this function will receive the packet and build fc frame and pass it up
 *
 * Returns: 0 for success
 */
int fcoe_rcv(struct sk_buff *skb, struct net_device *dev,
             struct packet_type *ptype, struct net_device *olddev)
{
        struct fc_lport *lp;
        struct fcoe_rcv_info *fr;
        struct fcoe_interface *fcoe;
        struct fc_frame_header *fh;
        struct fcoe_percpu_s *fps;
        unsigned int cpu;

        fcoe = container_of(ptype, struct fcoe_interface, fcoe_packet_type);
        lp = fcoe->ctlr.lp;
        if (unlikely(lp == NULL)) {
                FCOE_NETDEV_DBG(dev, "Cannot find hba structure");
                goto err2;
        }
        if (!lp->link_up)
                goto err2;

        FCOE_NETDEV_DBG(dev, "skb_info: len:%d data_len:%d head:%p "
                        "data:%p tail:%p end:%p sum:%d dev:%s",
                        skb->len, skb->data_len, skb->head, skb->data,
                        skb_tail_pointer(skb), skb_end_pointer(skb),
                        skb->csum, skb->dev ? skb->dev->name : "<NULL>");

        /* check for FCOE packet type */
        if (unlikely(eth_hdr(skb)->h_proto != htons(ETH_P_FCOE))) {
                FCOE_NETDEV_DBG(dev, "Wrong FC type frame");
                goto err;
        }

        /*
         * Check for minimum frame length, and make sure required FCoE
         * and FC headers are pulled into the linear data area.
         */
        if (unlikely((skb->len < FCOE_MIN_FRAME) ||
            !pskb_may_pull(skb, FCOE_HEADER_LEN)))
                goto err;

        skb_set_transport_header(skb, sizeof(struct fcoe_hdr));
        fh = (struct fc_frame_header *) skb_transport_header(skb);

        fr = fcoe_dev_from_skb(skb);
        fr->fr_dev = lp;
        fr->ptype = ptype;

        /*
         * In case the incoming frame's exchange is originated from
         * the initiator, then received frame's exchange id is ANDed
         * with fc_cpu_mask bits to get the same cpu on which exchange
         * was originated, otherwise just use the current cpu.
         */
        if (ntoh24(fh->fh_f_ctl) & FC_FC_EX_CTX)
                cpu = ntohs(fh->fh_ox_id) & fc_cpu_mask;
        else
                cpu = smp_processor_id();

        fps = &per_cpu(fcoe_percpu, cpu);
        spin_lock_bh(&fps->fcoe_rx_list.lock);
        if (unlikely(!fps->thread)) {
                /*
                 * The targeted CPU is not ready, let's target
                 * the first CPU now. For non-SMP systems this
                 * will check the same CPU twice.
                 */
                FCOE_NETDEV_DBG(dev, "CPU is online, but no receive thread "
                                "ready for incoming skb- using first online "
                                "CPU.\n");

                spin_unlock_bh(&fps->fcoe_rx_list.lock);
                cpu = first_cpu(cpu_online_map);
                fps = &per_cpu(fcoe_percpu, cpu);
                spin_lock_bh(&fps->fcoe_rx_list.lock);
                if (!fps->thread) {
                        spin_unlock_bh(&fps->fcoe_rx_list.lock);
                        goto err;
                }
        }

        /*
         * We now have a valid CPU that we're targeting for
         * this skb. We also have this receive thread locked,
         * so we're free to queue skbs into it's queue.
         */
        __skb_queue_tail(&fps->fcoe_rx_list, skb);
        if (fps->fcoe_rx_list.qlen == 1)
                wake_up_process(fps->thread);

        spin_unlock_bh(&fps->fcoe_rx_list.lock);

        return 0;
err:
        fc_lport_get_stats(lp)->ErrorFrames++;

err2:
        kfree_skb(skb);
        return -1;
}

/**
 * fcoe_start_io() - pass to netdev to start xmit for fcoe
 * @skb: the skb to be xmitted
 *
 * Returns: 0 for success
 */
static inline int fcoe_start_io(struct sk_buff *skb)
{
        int rc;

        skb_get(skb);
        rc = dev_queue_xmit(skb);
        if (rc != 0)
                return rc;
        kfree_skb(skb);
        return 0;
}

/**
 * fcoe_get_paged_crc_eof() - in case we need to alloc a page for crc_eof
 * @skb: the skb to be xmitted
 * @tlen: total len
 *
 * Returns: 0 for success
 */
static int fcoe_get_paged_crc_eof(struct sk_buff *skb, int tlen)
{
        struct fcoe_percpu_s *fps;
        struct page *page;

        fps = &get_cpu_var(fcoe_percpu);
        page = fps->crc_eof_page;
        if (!page) {
                page = alloc_page(GFP_ATOMIC);
                if (!page) {
                        put_cpu_var(fcoe_percpu);
                        return -ENOMEM;
                }
                fps->crc_eof_page = page;
                fps->crc_eof_offset = 0;
        }

        get_page(page);
        skb_fill_page_desc(skb, skb_shinfo(skb)->nr_frags, page,
                           fps->crc_eof_offset, tlen);
        skb->len += tlen;
        skb->data_len += tlen;
        skb->truesize += tlen;
        fps->crc_eof_offset += sizeof(struct fcoe_crc_eof);

        if (fps->crc_eof_offset >= PAGE_SIZE) {
                fps->crc_eof_page = NULL;
                fps->crc_eof_offset = 0;
                put_page(page);
        }
        put_cpu_var(fcoe_percpu);
        return 0;
}

/**
 * fcoe_fc_crc() - calculates FC CRC in this fcoe skb
 * @fp: the fc_frame containing data to be checksummed
 *
 * This uses crc32() to calculate the crc for port frame
 * Return   : 32 bit crc
 */
u32 fcoe_fc_crc(struct fc_frame *fp)
{
        struct sk_buff *skb = fp_skb(fp);
        struct skb_frag_struct *frag;
        unsigned char *data;
        unsigned long off, len, clen;
        u32 crc;
        unsigned i;

        crc = crc32(~0, skb->data, skb_headlen(skb));

        for (i = 0; i < skb_shinfo(skb)->nr_frags; i++) {
                frag = &skb_shinfo(skb)->frags[i];
                off = frag->page_offset;
                len = frag->size;
                while (len > 0) {
                        clen = min(len, PAGE_SIZE - (off & ~PAGE_MASK));
                        data = kmap_atomic(frag->page + (off >> PAGE_SHIFT),
                                           KM_SKB_DATA_SOFTIRQ);
                        crc = crc32(crc, data + (off & ~PAGE_MASK), clen);
                        kunmap_atomic(data, KM_SKB_DATA_SOFTIRQ);
                        off += clen;
                        len -= clen;
                }
        }
        return crc;
}

/**
 * fcoe_xmit() - FCoE frame transmit function
 * @lp: the associated local fcoe
 * @fp: the fc_frame to be transmitted
 *
 * Return   : 0 for success
 */
int fcoe_xmit(struct fc_lport *lp, struct fc_frame *fp)
{
        int wlen;
        u32 crc;
        struct ethhdr *eh;
        struct fcoe_crc_eof *cp;
        struct sk_buff *skb;
        struct fcoe_dev_stats *stats;
        struct fc_frame_header *fh;
        unsigned int hlen;              /* header length implies the version */
        unsigned int tlen;              /* trailer length */
        unsigned int elen;              /* eth header, may include vlan */
        struct fcoe_port *port = lport_priv(lp);
        struct fcoe_interface *fcoe = port->fcoe;
        u8 sof, eof;
        struct fcoe_hdr *hp;

        WARN_ON((fr_len(fp) % sizeof(u32)) != 0);

        fh = fc_frame_header_get(fp);
        skb = fp_skb(fp);
        wlen = skb->len / FCOE_WORD_TO_BYTE;

        if (!lp->link_up) {
                kfree_skb(skb);
                return 0;
        }

        if (unlikely(fh->fh_r_ctl == FC_RCTL_ELS_REQ) &&
            fcoe_ctlr_els_send(&fcoe->ctlr, skb))
                return 0;

        sof = fr_sof(fp);
        eof = fr_eof(fp);

        elen = sizeof(struct ethhdr);
        hlen = sizeof(struct fcoe_hdr);
        tlen = sizeof(struct fcoe_crc_eof);
        wlen = (skb->len - tlen + sizeof(crc)) / FCOE_WORD_TO_BYTE;

        /* crc offload */
        if (likely(lp->crc_offload)) {
                skb->ip_summed = CHECKSUM_PARTIAL;
                skb->csum_start = skb_headroom(skb);
                skb->csum_offset = skb->len;
                crc = 0;
        } else {
                skb->ip_summed = CHECKSUM_NONE;
                crc = fcoe_fc_crc(fp);
        }

        /* copy port crc and eof to the skb buff */
        if (skb_is_nonlinear(skb)) {
                skb_frag_t *frag;
                if (fcoe_get_paged_crc_eof(skb, tlen)) {
                        kfree_skb(skb);
                        return -ENOMEM;
                }
                frag = &skb_shinfo(skb)->frags[skb_shinfo(skb)->nr_frags - 1];
                cp = kmap_atomic(frag->page, KM_SKB_DATA_SOFTIRQ)
                        + frag->page_offset;
        } else {
                cp = (struct fcoe_crc_eof *)skb_put(skb, tlen);
        }

        memset(cp, 0, sizeof(*cp));
        cp->fcoe_eof = eof;
        cp->fcoe_crc32 = cpu_to_le32(~crc);

        if (skb_is_nonlinear(skb)) {
                kunmap_atomic(cp, KM_SKB_DATA_SOFTIRQ);
                cp = NULL;
        }

        /* adjust skb network/transport offsets to match mac/fcoe/port */
        skb_push(skb, elen + hlen);
        skb_reset_mac_header(skb);
        skb_reset_network_header(skb);
        skb->mac_len = elen;
        skb->protocol = htons(ETH_P_FCOE);
        skb->dev = fcoe->netdev;

        /* fill up mac and fcoe headers */
        eh = eth_hdr(skb);
        eh->h_proto = htons(ETH_P_FCOE);
        if (fcoe->ctlr.map_dest)
                fc_fcoe_set_mac(eh->h_dest, fh->fh_d_id);
        else
                /* insert GW address */
                memcpy(eh->h_dest, fcoe->ctlr.dest_addr, ETH_ALEN);

        if (unlikely(fcoe->ctlr.flogi_oxid != FC_XID_UNKNOWN))
                memcpy(eh->h_source, fcoe->ctlr.ctl_src_addr, ETH_ALEN);
        else
                memcpy(eh->h_source, fcoe->ctlr.data_src_addr, ETH_ALEN);

        hp = (struct fcoe_hdr *)(eh + 1);
        memset(hp, 0, sizeof(*hp));
        if (FC_FCOE_VER)
                FC_FCOE_ENCAPS_VER(hp, FC_FCOE_VER);
        hp->fcoe_sof = sof;

        /* fcoe lso, mss is in max_payload which is non-zero for FCP data */
        if (lp->seq_offload && fr_max_payload(fp)) {
                skb_shinfo(skb)->gso_type = SKB_GSO_FCOE;
                skb_shinfo(skb)->gso_size = fr_max_payload(fp);
        } else {
                skb_shinfo(skb)->gso_type = 0;
                skb_shinfo(skb)->gso_size = 0;
        }
        /* update tx stats: regardless if LLD fails */
        stats = fc_lport_get_stats(lp);
        stats->TxFrames++;
        stats->TxWords += wlen;

        /* send down to lld */
        fr_dev(fp) = lp;
        if (port->fcoe_pending_queue.qlen)
                fcoe_check_wait_queue(lp, skb);
        else if (fcoe_start_io(skb))
                fcoe_check_wait_queue(lp, skb);

        return 0;
}

/**
 * fcoe_percpu_receive_thread() - recv thread per cpu
 * @arg: ptr to the fcoe per cpu struct
 *
 * Return: 0 for success
 */
int fcoe_percpu_receive_thread(void *arg)
{
        struct fcoe_percpu_s *p = arg;
        u32 fr_len;
        struct fc_lport *lp;
        struct fcoe_rcv_info *fr;
        struct fcoe_dev_stats *stats;
        struct fc_frame_header *fh;
        struct sk_buff *skb;
        struct fcoe_crc_eof crc_eof;
        struct fc_frame *fp;
        u8 *mac = NULL;
        struct fcoe_port *port;
        struct fcoe_hdr *hp;

        set_user_nice(current, -20);

        while (!kthread_should_stop()) {

                spin_lock_bh(&p->fcoe_rx_list.lock);
                while ((skb = __skb_dequeue(&p->fcoe_rx_list)) == NULL) {
                        set_current_state(TASK_INTERRUPTIBLE);
                        spin_unlock_bh(&p->fcoe_rx_list.lock);
                        schedule();
                        set_current_state(TASK_RUNNING);
                        if (kthread_should_stop())
                                return 0;
                        spin_lock_bh(&p->fcoe_rx_list.lock);
                }
                spin_unlock_bh(&p->fcoe_rx_list.lock);
                fr = fcoe_dev_from_skb(skb);
                lp = fr->fr_dev;
                if (unlikely(lp == NULL)) {
                        FCOE_NETDEV_DBG(skb->dev, "Invalid HBA Structure");
                        kfree_skb(skb);
                        continue;
                }

                FCOE_NETDEV_DBG(skb->dev, "skb_info: len:%d data_len:%d "
                                "head:%p data:%p tail:%p end:%p sum:%d dev:%s",
                                skb->len, skb->data_len,
                                skb->head, skb->data, skb_tail_pointer(skb),
                                skb_end_pointer(skb), skb->csum,
                                skb->dev ? skb->dev->name : "<NULL>");

                /*
                 * Save source MAC address before discarding header.
                 */
                port = lport_priv(lp);
                if (skb_is_nonlinear(skb))
                        skb_linearize(skb);     /* not ideal */
                mac = eth_hdr(skb)->h_source;

                /*
                 * Frame length checks and setting up the header pointers
                 * was done in fcoe_rcv already.
                 */
                hp = (struct fcoe_hdr *) skb_network_header(skb);
                fh = (struct fc_frame_header *) skb_transport_header(skb);

                stats = fc_lport_get_stats(lp);
                if (unlikely(FC_FCOE_DECAPS_VER(hp) != FC_FCOE_VER)) {
                        if (stats->ErrorFrames < 5)
                                printk(KERN_WARNING "fcoe: FCoE version "
                                       "mismatch: The frame has "
                                       "version %x, but the "
                                       "initiator supports version "
                                       "%x\n", FC_FCOE_DECAPS_VER(hp),
                                       FC_FCOE_VER);
                        stats->ErrorFrames++;
                        kfree_skb(skb);
                        continue;
                }

                skb_pull(skb, sizeof(struct fcoe_hdr));
                fr_len = skb->len - sizeof(struct fcoe_crc_eof);

                stats->RxFrames++;
                stats->RxWords += fr_len / FCOE_WORD_TO_BYTE;

                fp = (struct fc_frame *)skb;
                fc_frame_init(fp);
                fr_dev(fp) = lp;
                fr_sof(fp) = hp->fcoe_sof;

                /* Copy out the CRC and EOF trailer for access */
                if (skb_copy_bits(skb, fr_len, &crc_eof, sizeof(crc_eof))) {
                        kfree_skb(skb);
                        continue;
                }
                fr_eof(fp) = crc_eof.fcoe_eof;
                fr_crc(fp) = crc_eof.fcoe_crc32;
                if (pskb_trim(skb, fr_len)) {
                        kfree_skb(skb);
                        continue;
                }

                /*
                 * We only check CRC if no offload is available and if it is
                 * it's solicited data, in which case, the FCP layer would
                 * check it during the copy.
                 */
                if (lp->crc_offload && skb->ip_summed == CHECKSUM_UNNECESSARY)
                        fr_flags(fp) &= ~FCPHF_CRC_UNCHECKED;
                else
                        fr_flags(fp) |= FCPHF_CRC_UNCHECKED;

                fh = fc_frame_header_get(fp);
                if (fh->fh_r_ctl == FC_RCTL_DD_SOL_DATA &&
                    fh->fh_type == FC_TYPE_FCP) {
                        fc_exch_recv(lp, fp);
                        continue;
                }
                if (fr_flags(fp) & FCPHF_CRC_UNCHECKED) {
                        if (le32_to_cpu(fr_crc(fp)) !=
                            ~crc32(~0, skb->data, fr_len)) {
                                if (stats->InvalidCRCCount < 5)
                                        printk(KERN_WARNING "fcoe: dropping "
                                               "frame with CRC error\n");
                                stats->InvalidCRCCount++;
                                stats->ErrorFrames++;
                                fc_frame_free(fp);
                                continue;
                        }
                        fr_flags(fp) &= ~FCPHF_CRC_UNCHECKED;
                }
                if (unlikely(port->fcoe->ctlr.flogi_oxid != FC_XID_UNKNOWN) &&
                    fcoe_ctlr_recv_flogi(&port->fcoe->ctlr, fp, mac)) {
                        fc_frame_free(fp);
                        continue;
                }
                fc_exch_recv(lp, fp);
        }
        return 0;
}

/**
 * fcoe_check_wait_queue() - attempt to clear the transmit backlog
 * @lp: the fc_lport
 *
 * This empties the wait_queue, dequeue the head of the wait_queue queue
 * and calls fcoe_start_io() for each packet, if all skb have been
 * transmitted, return qlen or -1 if a error occurs, then restore
 * wait_queue and try again later.
 *
 * The wait_queue is used when the skb transmit fails. skb will go
 * in the wait_queue which will be emptied by the timer function or
 * by the next skb transmit.
 */
static void fcoe_check_wait_queue(struct fc_lport *lp, struct sk_buff *skb)
{
        struct fcoe_port *port = lport_priv(lp);
        int rc;

        spin_lock_bh(&port->fcoe_pending_queue.lock);

        if (skb)
                __skb_queue_tail(&port->fcoe_pending_queue, skb);

        if (port->fcoe_pending_queue_active)
                goto out;
        port->fcoe_pending_queue_active = 1;

        while (port->fcoe_pending_queue.qlen) {
                /* keep qlen > 0 until fcoe_start_io succeeds */
                port->fcoe_pending_queue.qlen++;
                skb = __skb_dequeue(&port->fcoe_pending_queue);

                spin_unlock_bh(&port->fcoe_pending_queue.lock);
                rc = fcoe_start_io(skb);
                spin_lock_bh(&port->fcoe_pending_queue.lock);

                if (rc) {
                        __skb_queue_head(&port->fcoe_pending_queue, skb);
                        /* undo temporary increment above */
                        port->fcoe_pending_queue.qlen--;
                        break;
                }
                /* undo temporary increment above */
                port->fcoe_pending_queue.qlen--;
        }

        if (port->fcoe_pending_queue.qlen < FCOE_LOW_QUEUE_DEPTH)
                lp->qfull = 0;
        if (port->fcoe_pending_queue.qlen && !timer_pending(&port->timer))
                mod_timer(&port->timer, jiffies + 2);
        port->fcoe_pending_queue_active = 0;
out:
        if (port->fcoe_pending_queue.qlen > FCOE_MAX_QUEUE_DEPTH)
                lp->qfull = 1;
        spin_unlock_bh(&port->fcoe_pending_queue.lock);
        return;
}

/**
 * fcoe_dev_setup() - setup link change notification interface
 */
static void fcoe_dev_setup(void)
{
        register_netdevice_notifier(&fcoe_notifier);
}

/**
 * fcoe_dev_cleanup() - cleanup link change notification interface
 */
static void fcoe_dev_cleanup(void)
{
        unregister_netdevice_notifier(&fcoe_notifier);
}

/**
 * fcoe_device_notification() - netdev event notification callback
 * @notifier: context of the notification
 * @event: type of event
 * @ptr: fixed array for output parsed ifname
 *
 * This function is called by the ethernet driver in case of link change event
 *
 * Returns: 0 for success
 */
static int fcoe_device_notification(struct notifier_block *notifier,
                                    ulong event, void *ptr)
{
        struct fc_lport *lp = NULL;
        struct net_device *netdev = ptr;
        struct fcoe_interface *fcoe;
        struct fcoe_dev_stats *stats;
        u32 link_possible = 1;
        u32 mfs;
        int rc = NOTIFY_OK;

        read_lock(&fcoe_hostlist_lock);
        list_for_each_entry(fcoe, &fcoe_hostlist, list) {
                if (fcoe->netdev == netdev) {
                        lp = fcoe->ctlr.lp;
                        break;
                }
        }
        read_unlock(&fcoe_hostlist_lock);
        if (lp == NULL) {
                rc = NOTIFY_DONE;
                goto out;
        }

        switch (event) {
        case NETDEV_DOWN:
        case NETDEV_GOING_DOWN:
                link_possible = 0;
                break;
        case NETDEV_UP:
        case NETDEV_CHANGE:
                break;
        case NETDEV_CHANGEMTU:
                mfs = netdev->mtu - (sizeof(struct fcoe_hdr) +
                                     sizeof(struct fcoe_crc_eof));
                if (mfs >= FC_MIN_MAX_FRAME)
                        fc_set_mfs(lp, mfs);
                break;
        case NETDEV_REGISTER:
                break;
        default:
                FCOE_NETDEV_DBG(netdev, "Unknown event %ld "
                                "from netdev netlink\n", event);
        }
        if (link_possible && !fcoe_link_ok(lp))
                fcoe_ctlr_link_up(&fcoe->ctlr);
        else if (fcoe_ctlr_link_down(&fcoe->ctlr)) {
                stats = fc_lport_get_stats(lp);
                stats->LinkFailureCount++;
                fcoe_clean_pending_queue(lp);
        }
out:
        return rc;
}

/**
 * fcoe_if_to_netdev() - parse a name buffer to get netdev
 * @buffer: incoming buffer to be copied
 *
 * Returns: NULL or ptr to net_device
 */
static struct net_device *fcoe_if_to_netdev(const char *buffer)
{
        char *cp;
        char ifname[IFNAMSIZ + 2];

        if (buffer) {
                strlcpy(ifname, buffer, IFNAMSIZ);
                cp = ifname + strlen(ifname);
                while (--cp >= ifname && *cp == '\n')
                        *cp = '\0';
                return dev_get_by_name(&init_net, ifname);
        }
        return NULL;
}

/**
 * fcoe_netdev_to_module_owner() - finds out the driver module of the netdev
 * @netdev: the target netdev
 *
 * Returns: ptr to the struct module, NULL for failure
 */
static struct module *
fcoe_netdev_to_module_owner(const struct net_device *netdev)
{
        struct device *dev;

        if (!netdev)
                return NULL;

        dev = netdev->dev.parent;
        if (!dev)
                return NULL;

        if (!dev->driver)
                return NULL;

        return dev->driver->owner;
}

/**
 * fcoe_ethdrv_get() - Hold the Ethernet driver
 * @netdev: the target netdev
 *
 * Holds the Ethernet driver module by try_module_get() for
 * the corresponding netdev.
 *
 * Returns: 0 for success
 */
static int fcoe_ethdrv_get(const struct net_device *netdev)
{
        struct module *owner;

        owner = fcoe_netdev_to_module_owner(netdev);
        if (owner) {
                FCOE_NETDEV_DBG(netdev, "Hold driver module %s\n",
                                module_name(owner));
                return  try_module_get(owner);
        }
        return -ENODEV;
}

/**
 * fcoe_ethdrv_put() - Release the Ethernet driver
 * @netdev: the target netdev
 *
 * Releases the Ethernet driver module by module_put for
 * the corresponding netdev.
 *
 * Returns: 0 for success
 */
static int fcoe_ethdrv_put(const struct net_device *netdev)
{
        struct module *owner;

        owner = fcoe_netdev_to_module_owner(netdev);
        if (owner) {
                FCOE_NETDEV_DBG(netdev, "Release driver module %s\n",
                                module_name(owner));
                module_put(owner);
                return 0;
        }
        return -ENODEV;
}

/**
 * fcoe_destroy() - handles the destroy from sysfs
 * @buffer: expected to be an eth if name
 * @kp: associated kernel param
 *
 * Returns: 0 for success
 */
static int fcoe_destroy(const char *buffer, struct kernel_param *kp)
{
        struct net_device *netdev;
        struct fc_lport *lport;
        int rc;

        netdev = fcoe_if_to_netdev(buffer);
        if (!netdev) {
                rc = -ENODEV;
                goto out_nodev;
        }
        /* look for existing lport */
        lport = fcoe_hostlist_lookup(netdev);
        if (!lport) {
                rc = -ENODEV;
                goto out_putdev;
        }
        fcoe_if_destroy(lport);
        fcoe_ethdrv_put(netdev);
        rc = 0;
out_putdev:
        dev_put(netdev);
out_nodev:
        return rc;
}

/**
 * fcoe_create() - Handles the create call from sysfs
 * @buffer: expected to be an eth if name
 * @kp: associated kernel param
 *
 * Returns: 0 for success
 */
static int fcoe_create(const char *buffer, struct kernel_param *kp)
{
        int rc;
        struct fc_lport *lport;
        struct net_device *netdev;

        netdev = fcoe_if_to_netdev(buffer);
        if (!netdev) {
                rc = -ENODEV;
                goto out_nodev;
        }
        /* look for existing lport */
        if (fcoe_hostlist_lookup(netdev)) {
                rc = -EEXIST;
                goto out_putdev;
        }
        fcoe_ethdrv_get(netdev);

        lport = fcoe_if_create(netdev, &netdev->dev);
        if (IS_ERR(lport)) {
                printk(KERN_ERR "fcoe: Failed to create interface (%s)\n",
                       netdev->name);
                fcoe_ethdrv_put(netdev);
                rc = -EIO;
                goto out_putdev;
        }
        rc = 0;
out_putdev:
        dev_put(netdev);
out_nodev:
        return rc;
}

module_param_call(create, fcoe_create, NULL, NULL, S_IWUSR);
__MODULE_PARM_TYPE(create, "string");
MODULE_PARM_DESC(create, "Create fcoe fcoe using net device passed in.");
module_param_call(destroy, fcoe_destroy, NULL, NULL, S_IWUSR);
__MODULE_PARM_TYPE(destroy, "string");
MODULE_PARM_DESC(destroy, "Destroy fcoe fcoe");

/**
 * fcoe_link_ok() - Check if link is ok for the fc_lport
 * @lp: ptr to the fc_lport
 *
 * Any permanently-disqualifying conditions have been previously checked.
 * This also updates the speed setting, which may change with link for 100/1000.
 *
 * This function should probably be checking for PAUSE support at some point
 * in the future. Currently Per-priority-pause is not determinable using
 * ethtool, so we shouldn't be restrictive until that problem is resolved.
 *
 * Returns: 0 if link is OK for use by FCoE.
 *
 */
int fcoe_link_ok(struct fc_lport *lp)
{
        struct fcoe_port *port = lport_priv(lp);
        struct net_device *dev = port->fcoe->netdev;
        struct ethtool_cmd ecmd = { ETHTOOL_GSET };

        if ((dev->flags & IFF_UP) && netif_carrier_ok(dev) &&
            (!dev_ethtool_get_settings(dev, &ecmd))) {
                lp->link_supported_speeds &=
                        ~(FC_PORTSPEED_1GBIT | FC_PORTSPEED_10GBIT);
                if (ecmd.supported & (SUPPORTED_1000baseT_Half |
                                      SUPPORTED_1000baseT_Full))
                        lp->link_supported_speeds |= FC_PORTSPEED_1GBIT;
                if (ecmd.supported & SUPPORTED_10000baseT_Full)
                        lp->link_supported_speeds |=
                                FC_PORTSPEED_10GBIT;
                if (ecmd.speed == SPEED_1000)
                        lp->link_speed = FC_PORTSPEED_1GBIT;
                if (ecmd.speed == SPEED_10000)
                        lp->link_speed = FC_PORTSPEED_10GBIT;

                return 0;
        }
        return -1;
}

/**
 * fcoe_percpu_clean() - Clear the pending skbs for an lport
 * @lp: the fc_lport
 */
void fcoe_percpu_clean(struct fc_lport *lp)
{
        struct fcoe_percpu_s *pp;
        struct fcoe_rcv_info *fr;
        struct sk_buff_head *list;
        struct sk_buff *skb, *next;
        struct sk_buff *head;
        unsigned int cpu;

        for_each_possible_cpu(cpu) {
                pp = &per_cpu(fcoe_percpu, cpu);
                spin_lock_bh(&pp->fcoe_rx_list.lock);
                list = &pp->fcoe_rx_list;
                head = list->next;
                for (skb = head; skb != (struct sk_buff *)list;
                     skb = next) {
                        next = skb->next;
                        fr = fcoe_dev_from_skb(skb);
                        if (fr->fr_dev == lp) {
                                __skb_unlink(skb, list);
                                kfree_skb(skb);
                        }
                }
                spin_unlock_bh(&pp->fcoe_rx_list.lock);
        }
}

/**
 * fcoe_clean_pending_queue() - Dequeue a skb and free it
 * @lp: the corresponding fc_lport
 *
 * Returns: none
 */
void fcoe_clean_pending_queue(struct fc_lport *lp)
{
        struct fcoe_port  *port = lport_priv(lp);
        struct sk_buff *skb;

        spin_lock_bh(&port->fcoe_pending_queue.lock);
        while ((skb = __skb_dequeue(&port->fcoe_pending_queue)) != NULL) {
                spin_unlock_bh(&port->fcoe_pending_queue.lock);
                kfree_skb(skb);
                spin_lock_bh(&port->fcoe_pending_queue.lock);
        }
        spin_unlock_bh(&port->fcoe_pending_queue.lock);
}

/**
 * fcoe_reset() - Resets the fcoe
 * @shost: shost the reset is from
 *
 * Returns: always 0
 */
int fcoe_reset(struct Scsi_Host *shost)
{
        struct fc_lport *lport = shost_priv(shost);
        fc_lport_reset(lport);
        return 0;
}

/**
 * fcoe_hostlist_lookup_port() - find the corresponding lport by a given device
 * @dev: this is currently ptr to net_device
 *
 * Called with fcoe_hostlist_lock held.
 *
 * Returns: NULL or the located fcoe_port
 */
static struct fcoe_interface *
fcoe_hostlist_lookup_port(const struct net_device *dev)
{
        struct fcoe_interface *fcoe;

        list_for_each_entry(fcoe, &fcoe_hostlist, list) {
                if (fcoe->netdev == dev)
                        return fcoe;
        }
        return NULL;
}

/**
 * fcoe_hostlist_lookup() - Find the corresponding lport by netdev
 * @netdev: ptr to net_device
 *
 * Returns: 0 for success
 */
struct fc_lport *fcoe_hostlist_lookup(const struct net_device *netdev)
{
        struct fcoe_interface *fcoe;

        read_lock(&fcoe_hostlist_lock);
        fcoe = fcoe_hostlist_lookup_port(netdev);
        read_unlock(&fcoe_hostlist_lock);

        return (fcoe) ? fcoe->ctlr.lp : NULL;
}

/**
 * fcoe_hostlist_add() - Add a lport to lports list
 * @lp: ptr to the fc_lport to be added
 *
 * Called with write fcoe_hostlist_lock held.
 *
 * Returns: 0 for success
 */
int fcoe_hostlist_add(const struct fc_lport *lport)
{
        struct fcoe_interface *fcoe;
        struct fcoe_port *port;

        fcoe = fcoe_hostlist_lookup_port(fcoe_netdev(lport));
        if (!fcoe) {
                port = lport_priv(lport);
                fcoe = port->fcoe;
                list_add_tail(&fcoe->list, &fcoe_hostlist);
        }
        return 0;
}

/**
 * fcoe_hostlist_remove() - remove a lport from lports list
 * @lp: ptr to the fc_lport to be removed
 *
 * Returns: 0 for success
 */
int fcoe_hostlist_remove(const struct fc_lport *lport)
{
        struct fcoe_interface *fcoe;

        write_lock_bh(&fcoe_hostlist_lock);
        fcoe = fcoe_hostlist_lookup_port(fcoe_netdev(lport));
        BUG_ON(!fcoe);
        list_del(&fcoe->list);
        write_unlock_bh(&fcoe_hostlist_lock);

        return 0;
}

/**
 * fcoe_init() - fcoe module loading initialization
 *
 * Returns 0 on success, negative on failure
 */
static int __init fcoe_init(void)
{
        unsigned int cpu;
        int rc = 0;
        struct fcoe_percpu_s *p;

        for_each_possible_cpu(cpu) {
                p = &per_cpu(fcoe_percpu, cpu);
                skb_queue_head_init(&p->fcoe_rx_list);
        }

        for_each_online_cpu(cpu)
                fcoe_percpu_thread_create(cpu);

        /* Initialize per CPU interrupt thread */
        rc = register_hotcpu_notifier(&fcoe_cpu_notifier);
        if (rc)
                goto out_free;

        /* Setup link change notification */
        fcoe_dev_setup();

        rc = fcoe_if_init();
        if (rc)
                goto out_free;

        return 0;

out_free:
        for_each_online_cpu(cpu) {
                fcoe_percpu_thread_destroy(cpu);
        }

        return rc;
}
module_init(fcoe_init);

/**
 * fcoe_exit() - fcoe module unloading cleanup
 *
 * Returns 0 on success, negative on failure
 */
static void __exit fcoe_exit(void)
{
        unsigned int cpu;
        struct fcoe_interface *fcoe, *tmp;

        fcoe_dev_cleanup();

        /* releases the associated fcoe hosts */
        list_for_each_entry_safe(fcoe, tmp, &fcoe_hostlist, list)
                fcoe_if_destroy(fcoe->ctlr.lp);

        unregister_hotcpu_notifier(&fcoe_cpu_notifier);

        for_each_online_cpu(cpu)
                fcoe_percpu_thread_destroy(cpu);

        /* detach from scsi transport */
        fcoe_if_exit();
}
module_exit(fcoe_exit);