/*
 * Copyright(c) 2007 - 2008 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
 */

/*
 * RPORT GENERAL INFO
 *
 * This file contains all processing regarding fc_rports. It contains the
 * rport state machine and does all rport interaction with the transport class.
 * There should be no other places in libfc that interact directly with the
 * transport class in regards to adding and deleting rports.
 *
 * fc_rport's represent N_Port's within the fabric.
 */

/*
 * RPORT LOCKING
 *
 * The rport should never hold the rport mutex and then attempt to acquire
 * either the lport or disc mutexes. The rport's mutex is considered lesser
 * than both the lport's mutex and the disc mutex. Refer to fc_lport.c for
 * more comments on the hierarchy.
 *
 * The locking strategy is similar to the lport's strategy. The lock protects
 * the rport's states and is held and released by the entry points to the rport
 * block. All _enter_* functions correspond to rport states and expect the rport
 * mutex to be locked before calling them. This means that rports only handle
 * one request or response at a time, since they're not critical for the I/O
 * path this potential over-use of the mutex is acceptable.
 */

#include <linux/kernel.h>
#include <linux/spinlock.h>
#include <linux/interrupt.h>
#include <linux/slab.h>
#include <linux/rcupdate.h>
#include <linux/timer.h>
#include <linux/workqueue.h>
#include <linux/export.h>
#include <asm/unaligned.h>

#include <scsi/libfc.h>
#include <scsi/fc_encode.h>

#include "fc_libfc.h"

static struct workqueue_struct *rport_event_queue;

static void fc_rport_enter_flogi(struct fc_rport_priv *);
static void fc_rport_enter_plogi(struct fc_rport_priv *);
static void fc_rport_enter_prli(struct fc_rport_priv *);
static void fc_rport_enter_rtv(struct fc_rport_priv *);
static void fc_rport_enter_ready(struct fc_rport_priv *);
static void fc_rport_enter_logo(struct fc_rport_priv *);
static void fc_rport_enter_adisc(struct fc_rport_priv *);

static void fc_rport_recv_plogi_req(struct fc_lport *, struct fc_frame *);
static void fc_rport_recv_prli_req(struct fc_rport_priv *, struct fc_frame *);
static void fc_rport_recv_prlo_req(struct fc_rport_priv *, struct fc_frame *);
static void fc_rport_recv_logo_req(struct fc_lport *, struct fc_frame *);
static void fc_rport_timeout(struct work_struct *);
static void fc_rport_error(struct fc_rport_priv *, struct fc_frame *);
static void fc_rport_error_retry(struct fc_rport_priv *, struct fc_frame *);
static void fc_rport_work(struct work_struct *);

static const char *fc_rport_state_names[] = {
        [RPORT_ST_INIT] = "Init",
        [RPORT_ST_FLOGI] = "FLOGI",
        [RPORT_ST_PLOGI_WAIT] = "PLOGI_WAIT",
        [RPORT_ST_PLOGI] = "PLOGI",
        [RPORT_ST_PRLI] = "PRLI",
        [RPORT_ST_RTV] = "RTV",
        [RPORT_ST_READY] = "Ready",
        [RPORT_ST_ADISC] = "ADISC",
        [RPORT_ST_DELETE] = "Delete",
};

/**
 * fc_rport_lookup() - Lookup a remote port by port_id
 * @lport:   The local port to lookup the remote port on
 * @port_id: The remote port ID to look up
 *
 * The reference count of the fc_rport_priv structure is
 * increased by one.
 */
static struct fc_rport_priv *fc_rport_lookup(const struct fc_lport *lport,
                                             u32 port_id)
{
        struct fc_rport_priv *rdata = NULL, *tmp_rdata;

        rcu_read_lock();
        list_for_each_entry_rcu(tmp_rdata, &lport->disc.rports, peers)
                if (tmp_rdata->ids.port_id == port_id &&
                    kref_get_unless_zero(&tmp_rdata->kref)) {
                        rdata = tmp_rdata;
                        break;
                }
        rcu_read_unlock();
        return rdata;
}

/**
 * fc_rport_create() - Create a new remote port
 * @lport: The local port this remote port will be associated with
 * @ids:   The identifiers for the new remote port
 *
 * The remote port will start in the INIT state.
 */
static struct fc_rport_priv *fc_rport_create(struct fc_lport *lport,
                                             u32 port_id)
{
        struct fc_rport_priv *rdata;

        lockdep_assert_held(&lport->disc.disc_mutex);

        rdata = lport->tt.rport_lookup(lport, port_id);
        if (rdata)
                return rdata;

        rdata = kzalloc(sizeof(*rdata) + lport->rport_priv_size, GFP_KERNEL);
        if (!rdata)
                return NULL;

        rdata->ids.node_name = -1;
        rdata->ids.port_name = -1;
        rdata->ids.port_id = port_id;
        rdata->ids.roles = FC_RPORT_ROLE_UNKNOWN;

        kref_init(&rdata->kref);
        mutex_init(&rdata->rp_mutex);
        rdata->local_port = lport;
        rdata->rp_state = RPORT_ST_INIT;
        rdata->event = RPORT_EV_NONE;
        rdata->flags = FC_RP_FLAGS_REC_SUPPORTED;
        rdata->e_d_tov = lport->e_d_tov;
        rdata->r_a_tov = lport->r_a_tov;
        rdata->maxframe_size = FC_MIN_MAX_PAYLOAD;
        INIT_DELAYED_WORK(&rdata->retry_work, fc_rport_timeout);
        INIT_WORK(&rdata->event_work, fc_rport_work);
        if (port_id != FC_FID_DIR_SERV) {
                rdata->lld_event_callback = lport->tt.rport_event_callback;
                list_add_rcu(&rdata->peers, &lport->disc.rports);
        }
        return rdata;
}

/**
 * fc_rport_destroy() - Free a remote port after last reference is released
 * @kref: The remote port's kref
 */
static void fc_rport_destroy(struct kref *kref)
{
        struct fc_rport_priv *rdata;

        rdata = container_of(kref, struct fc_rport_priv, kref);
        kfree_rcu(rdata, rcu);
}

/**
 * fc_rport_state() - Return a string identifying the remote port's state
 * @rdata: The remote port
 */
static const char *fc_rport_state(struct fc_rport_priv *rdata)
{
        const char *cp;

        cp = fc_rport_state_names[rdata->rp_state];
        if (!cp)
                cp = "Unknown";
        return cp;
}

/**
 * fc_set_rport_loss_tmo() - Set the remote port loss timeout
 * @rport:   The remote port that gets a new timeout value
 * @timeout: The new timeout value (in seconds)
 */
void fc_set_rport_loss_tmo(struct fc_rport *rport, u32 timeout)
{
        if (timeout)
                rport->dev_loss_tmo = timeout;
        else
                rport->dev_loss_tmo = 1;
}
EXPORT_SYMBOL(fc_set_rport_loss_tmo);

/**
 * fc_plogi_get_maxframe() - Get the maximum payload from the common service
 *                           parameters in a FLOGI frame
 * @flp:    The FLOGI or PLOGI payload
 * @maxval: The maximum frame size upper limit; this may be less than what
 *          is in the service parameters
 */
static unsigned int fc_plogi_get_maxframe(struct fc_els_flogi *flp,
                                          unsigned int maxval)
{
        unsigned int mfs;

        /*
         * Get max payload from the common service parameters and the
         * class 3 receive data field size.
         */
        mfs = ntohs(flp->fl_csp.sp_bb_data) & FC_SP_BB_DATA_MASK;
        if (mfs >= FC_SP_MIN_MAX_PAYLOAD && mfs < maxval)
                maxval = mfs;
        mfs = ntohs(flp->fl_cssp[3 - 1].cp_rdfs);
        if (mfs >= FC_SP_MIN_MAX_PAYLOAD && mfs < maxval)
                maxval = mfs;
        return maxval;
}

/**
 * fc_rport_state_enter() - Change the state of a remote port
 * @rdata: The remote port whose state should change
 * @new:   The new state
 */
static void fc_rport_state_enter(struct fc_rport_priv *rdata,
                                 enum fc_rport_state new)
{
        lockdep_assert_held(&rdata->rp_mutex);

        if (rdata->rp_state != new)
                rdata->retries = 0;
        rdata->rp_state = new;
}

/**
 * fc_rport_work() - Handler for remote port events in the rport_event_queue
 * @work: Handle to the remote port being dequeued
 */
static void fc_rport_work(struct work_struct *work)
{
        u32 port_id;
        struct fc_rport_priv *rdata =
                container_of(work, struct fc_rport_priv, event_work);
        struct fc_rport_libfc_priv *rpriv;
        enum fc_rport_event event;
        struct fc_lport *lport = rdata->local_port;
        struct fc_rport_operations *rport_ops;
        struct fc_rport_identifiers ids;
        struct fc_rport *rport;
        struct fc4_prov *prov;
        u8 type;

        mutex_lock(&rdata->rp_mutex);
        event = rdata->event;
        rport_ops = rdata->ops;
        rport = rdata->rport;

        FC_RPORT_DBG(rdata, "work event %u\n", event);

        switch (event) {
        case RPORT_EV_READY:
                ids = rdata->ids;
                rdata->event = RPORT_EV_NONE;
                rdata->major_retries = 0;
                kref_get(&rdata->kref);
                mutex_unlock(&rdata->rp_mutex);

                if (!rport)
                        rport = fc_remote_port_add(lport->host, 0, &ids);
                if (!rport) {
                        FC_RPORT_DBG(rdata, "Failed to add the rport\n");
                        lport->tt.rport_logoff(rdata);
                        kref_put(&rdata->kref, lport->tt.rport_destroy);
                        return;
                }
                mutex_lock(&rdata->rp_mutex);
                if (rdata->rport)
                        FC_RPORT_DBG(rdata, "rport already allocated\n");
                rdata->rport = rport;
                rport->maxframe_size = rdata->maxframe_size;
                rport->supported_classes = rdata->supported_classes;

                rpriv = rport->dd_data;
                rpriv->local_port = lport;
                rpriv->rp_state = rdata->rp_state;
                rpriv->flags = rdata->flags;
                rpriv->e_d_tov = rdata->e_d_tov;
                rpriv->r_a_tov = rdata->r_a_tov;
                mutex_unlock(&rdata->rp_mutex);

                if (rport_ops && rport_ops->event_callback) {
                        FC_RPORT_DBG(rdata, "callback ev %d\n", event);
                        rport_ops->event_callback(lport, rdata, event);
                }
                if (rdata->lld_event_callback) {
                        FC_RPORT_DBG(rdata, "lld callback ev %d\n", event);
                        rdata->lld_event_callback(lport, rdata, event);
                }
                kref_put(&rdata->kref, lport->tt.rport_destroy);
                break;

        case RPORT_EV_FAILED:
        case RPORT_EV_LOGO:
        case RPORT_EV_STOP:
                if (rdata->prli_count) {
                        mutex_lock(&fc_prov_mutex);
                        for (type = 1; type < FC_FC4_PROV_SIZE; type++) {
                                prov = fc_passive_prov[type];
                                if (prov && prov->prlo)
                                        prov->prlo(rdata);
                        }
                        mutex_unlock(&fc_prov_mutex);
                }
                port_id = rdata->ids.port_id;
                mutex_unlock(&rdata->rp_mutex);

                if (rport_ops && rport_ops->event_callback) {
                        FC_RPORT_DBG(rdata, "callback ev %d\n", event);
                        rport_ops->event_callback(lport, rdata, event);
                }
                if (rdata->lld_event_callback) {
                        FC_RPORT_DBG(rdata, "lld callback ev %d\n", event);
                        rdata->lld_event_callback(lport, rdata, event);
                }
                cancel_delayed_work_sync(&rdata->retry_work);

                /*
                 * Reset any outstanding exchanges before freeing rport.
                 */
                lport->tt.exch_mgr_reset(lport, 0, port_id);
                lport->tt.exch_mgr_reset(lport, port_id, 0);

                if (rport) {
                        rpriv = rport->dd_data;
                        rpriv->rp_state = RPORT_ST_DELETE;
                        mutex_lock(&rdata->rp_mutex);
                        rdata->rport = NULL;
                        mutex_unlock(&rdata->rp_mutex);
                        fc_remote_port_delete(rport);
                }

                mutex_lock(&rdata->rp_mutex);
                if (rdata->rp_state == RPORT_ST_DELETE) {
                        if (port_id == FC_FID_DIR_SERV) {
                                rdata->event = RPORT_EV_NONE;
                                mutex_unlock(&rdata->rp_mutex);
                                kref_put(&rdata->kref, lport->tt.rport_destroy);
                        } else if ((rdata->flags & FC_RP_STARTED) &&
                                   rdata->major_retries <
                                   lport->max_rport_retry_count) {
                                rdata->major_retries++;
                                rdata->event = RPORT_EV_NONE;
                                FC_RPORT_DBG(rdata, "work restart\n");
                                fc_rport_enter_flogi(rdata);
                                mutex_unlock(&rdata->rp_mutex);
                        } else {
                                mutex_unlock(&rdata->rp_mutex);
                                FC_RPORT_DBG(rdata, "work delete\n");
                                mutex_lock(&lport->disc.disc_mutex);
                                list_del_rcu(&rdata->peers);
                                mutex_unlock(&lport->disc.disc_mutex);
                                kref_put(&rdata->kref, lport->tt.rport_destroy);
                        }
                } else {
                        /*
                         * Re-open for events.  Reissue READY event if ready.
                         */
                        rdata->event = RPORT_EV_NONE;
                        if (rdata->rp_state == RPORT_ST_READY)
                                fc_rport_enter_ready(rdata);
                        mutex_unlock(&rdata->rp_mutex);
                }
                break;

        default:
                mutex_unlock(&rdata->rp_mutex);
                break;
        }
}

/**
 * fc_rport_login() - Start the remote port login state machine
 * @rdata: The remote port to be logged in to
 *
 * Locking Note: Called without the rport lock held. This
 * function will hold the rport lock, call an _enter_*
 * function and then unlock the rport.
 *
 * This indicates the intent to be logged into the remote port.
 * If it appears we are already logged in, ADISC is used to verify
 * the setup.
 */
static int fc_rport_login(struct fc_rport_priv *rdata)
{
        mutex_lock(&rdata->rp_mutex);

        if (rdata->flags & FC_RP_STARTED) {
                FC_RPORT_DBG(rdata, "port already started\n");
                mutex_unlock(&rdata->rp_mutex);
                return 0;
        }

        rdata->flags |= FC_RP_STARTED;
        switch (rdata->rp_state) {
        case RPORT_ST_READY:
                FC_RPORT_DBG(rdata, "ADISC port\n");
                fc_rport_enter_adisc(rdata);
                break;
        case RPORT_ST_DELETE:
                FC_RPORT_DBG(rdata, "Restart deleted port\n");
                break;
        case RPORT_ST_INIT:
                FC_RPORT_DBG(rdata, "Login to port\n");
                fc_rport_enter_flogi(rdata);
                break;
        default:
                FC_RPORT_DBG(rdata, "Login in progress, state %s\n",
                             fc_rport_state(rdata));
                break;
        }
        mutex_unlock(&rdata->rp_mutex);

        return 0;
}

/**
 * fc_rport_enter_delete() - Schedule a remote port to be deleted
 * @rdata: The remote port to be deleted
 * @event: The event to report as the reason for deletion
 *
 * Allow state change into DELETE only once.
 *
 * Call queue_work only if there's no event already pending.
 * Set the new event so that the old pending event will not occur.
 * Since we have the mutex, even if fc_rport_work() is already started,
 * it'll see the new event.
 */
static void fc_rport_enter_delete(struct fc_rport_priv *rdata,
                                  enum fc_rport_event event)
{
        lockdep_assert_held(&rdata->rp_mutex);

        if (rdata->rp_state == RPORT_ST_DELETE)
                return;

        FC_RPORT_DBG(rdata, "Delete port\n");

        fc_rport_state_enter(rdata, RPORT_ST_DELETE);

        if (rdata->event == RPORT_EV_NONE)
                queue_work(rport_event_queue, &rdata->event_work);
        rdata->event = event;
}

/**
 * fc_rport_logoff() - Logoff and remove a remote port
 * @rdata: The remote port to be logged off of
 *
 * Locking Note: Called without the rport lock held. This
 * function will hold the rport lock, call an _enter_*
 * function and then unlock the rport.
 */
static int fc_rport_logoff(struct fc_rport_priv *rdata)
{
        mutex_lock(&rdata->rp_mutex);

        FC_RPORT_DBG(rdata, "Remove port\n");

        rdata->flags &= ~FC_RP_STARTED;
        if (rdata->rp_state == RPORT_ST_DELETE) {
                FC_RPORT_DBG(rdata, "Port in Delete state, not removing\n");
                goto out;
        }
        fc_rport_enter_logo(rdata);

        /*
         * Change the state to Delete so that we discard
         * the response.
         */
        fc_rport_enter_delete(rdata, RPORT_EV_STOP);
out:
        mutex_unlock(&rdata->rp_mutex);
        return 0;
}

/**
 * fc_rport_enter_ready() - Transition to the RPORT_ST_READY state
 * @rdata: The remote port that is ready
 */
static void fc_rport_enter_ready(struct fc_rport_priv *rdata)
{
        lockdep_assert_held(&rdata->rp_mutex);

        fc_rport_state_enter(rdata, RPORT_ST_READY);

        FC_RPORT_DBG(rdata, "Port is Ready\n");

        if (rdata->event == RPORT_EV_NONE)
                queue_work(rport_event_queue, &rdata->event_work);
        rdata->event = RPORT_EV_READY;
}

/**
 * fc_rport_timeout() - Handler for the retry_work timer
 * @work: Handle to the remote port that has timed out
 *
 * Locking Note: Called without the rport lock held. This
 * function will hold the rport lock, call an _enter_*
 * function and then unlock the rport.
 */
static void fc_rport_timeout(struct work_struct *work)
{
        struct fc_rport_priv *rdata =
                container_of(work, struct fc_rport_priv, retry_work.work);

        mutex_lock(&rdata->rp_mutex);

        switch (rdata->rp_state) {
        case RPORT_ST_FLOGI:
                fc_rport_enter_flogi(rdata);
                break;
        case RPORT_ST_PLOGI:
                fc_rport_enter_plogi(rdata);
                break;
        case RPORT_ST_PRLI:
                fc_rport_enter_prli(rdata);
                break;
        case RPORT_ST_RTV:
                fc_rport_enter_rtv(rdata);
                break;
        case RPORT_ST_ADISC:
                fc_rport_enter_adisc(rdata);
                break;
        case RPORT_ST_PLOGI_WAIT:
        case RPORT_ST_READY:
        case RPORT_ST_INIT:
        case RPORT_ST_DELETE:
                break;
        }

        mutex_unlock(&rdata->rp_mutex);
}

/**
 * fc_rport_error() - Error handler, called once retries have been exhausted
 * @rdata: The remote port the error is happened on
 * @fp:    The error code encapsulated in a frame pointer
 */
static void fc_rport_error(struct fc_rport_priv *rdata, struct fc_frame *fp)
{
        lockdep_assert_held(&rdata->rp_mutex);

        FC_RPORT_DBG(rdata, "Error %ld in state %s, retries %d\n",
                     IS_ERR(fp) ? -PTR_ERR(fp) : 0,
                     fc_rport_state(rdata), rdata->retries);

        switch (rdata->rp_state) {
        case RPORT_ST_FLOGI:
        case RPORT_ST_PLOGI:
                rdata->flags &= ~FC_RP_STARTED;
                fc_rport_enter_delete(rdata, RPORT_EV_FAILED);
                break;
        case RPORT_ST_RTV:
                fc_rport_enter_ready(rdata);
                break;
        case RPORT_ST_PRLI:
        case RPORT_ST_ADISC:
                fc_rport_enter_logo(rdata);
                break;
        case RPORT_ST_PLOGI_WAIT:
        case RPORT_ST_DELETE:
        case RPORT_ST_READY:
        case RPORT_ST_INIT:
                break;
        }
}

/**
 * fc_rport_error_retry() - Handler for remote port state retries
 * @rdata: The remote port whose state is to be retried
 * @fp:    The error code encapsulated in a frame pointer
 *
 * If the error was an exchange timeout retry immediately,
 * otherwise wait for E_D_TOV.
 */
static void fc_rport_error_retry(struct fc_rport_priv *rdata,
                                 struct fc_frame *fp)
{
        unsigned long delay = msecs_to_jiffies(FC_DEF_E_D_TOV);

        lockdep_assert_held(&rdata->rp_mutex);

        /* make sure this isn't an FC_EX_CLOSED error, never retry those */
        if (PTR_ERR(fp) == -FC_EX_CLOSED)
                goto out;

        if (rdata->retries < rdata->local_port->max_rport_retry_count) {
                FC_RPORT_DBG(rdata, "Error %ld in state %s, retrying\n",
                             PTR_ERR(fp), fc_rport_state(rdata));
                rdata->retries++;
                /* no additional delay on exchange timeouts */
                if (PTR_ERR(fp) == -FC_EX_TIMEOUT)
                        delay = 0;
                schedule_delayed_work(&rdata->retry_work, delay);
                return;
        }

out:
        fc_rport_error(rdata, fp);
}

/**
 * fc_rport_login_complete() - Handle parameters and completion of p-mp login.
 * @rdata:  The remote port which we logged into or which logged into us.
 * @fp:     The FLOGI or PLOGI request or response frame
 *
 * Returns non-zero error if a problem is detected with the frame.
 * Does not free the frame.
 *
 * This is only used in point-to-multipoint mode for FIP currently.
 */
static int fc_rport_login_complete(struct fc_rport_priv *rdata,
                                   struct fc_frame *fp)
{
        struct fc_lport *lport = rdata->local_port;
        struct fc_els_flogi *flogi;
        unsigned int e_d_tov;
        u16 csp_flags;

        flogi = fc_frame_payload_get(fp, sizeof(*flogi));
        if (!flogi)
                return -EINVAL;

        csp_flags = ntohs(flogi->fl_csp.sp_features);

        if (fc_frame_payload_op(fp) == ELS_FLOGI) {
                if (csp_flags & FC_SP_FT_FPORT) {
                        FC_RPORT_DBG(rdata, "Fabric bit set in FLOGI\n");
                        return -EINVAL;
                }
        } else {

                /*
                 * E_D_TOV is not valid on an incoming FLOGI request.
                 */
                e_d_tov = ntohl(flogi->fl_csp.sp_e_d_tov);
                if (csp_flags & FC_SP_FT_EDTR)
                        e_d_tov /= 1000000;
                if (e_d_tov > rdata->e_d_tov)
                        rdata->e_d_tov = e_d_tov;
        }
        rdata->maxframe_size = fc_plogi_get_maxframe(flogi, lport->mfs);
        return 0;
}

/**
 * fc_rport_flogi_resp() - Handle response to FLOGI request for p-mp mode
 * @sp:     The sequence that the FLOGI was on
 * @fp:     The FLOGI response frame
 * @rp_arg: The remote port that received the FLOGI response
 */
static void fc_rport_flogi_resp(struct fc_seq *sp, struct fc_frame *fp,
                                void *rp_arg)
{
        struct fc_rport_priv *rdata = rp_arg;
        struct fc_lport *lport = rdata->local_port;
        struct fc_els_flogi *flogi;
        unsigned int r_a_tov;

        FC_RPORT_DBG(rdata, "Received a FLOGI %s\n", fc_els_resp_type(fp));

        if (fp == ERR_PTR(-FC_EX_CLOSED))
                goto put;

        mutex_lock(&rdata->rp_mutex);

        if (rdata->rp_state != RPORT_ST_FLOGI) {
                FC_RPORT_DBG(rdata, "Received a FLOGI response, but in state "
                             "%s\n", fc_rport_state(rdata));
                if (IS_ERR(fp))
                        goto err;
                goto out;
        }

        if (IS_ERR(fp)) {
                fc_rport_error(rdata, fp);
                goto err;
        }

        if (fc_frame_payload_op(fp) != ELS_LS_ACC)
                goto bad;
        if (fc_rport_login_complete(rdata, fp))
                goto bad;

        flogi = fc_frame_payload_get(fp, sizeof(*flogi));
        if (!flogi) {
                FC_RPORT_DBG(rdata, "Bad FLOGI response\n");
                goto bad;
        }
        r_a_tov = ntohl(flogi->fl_csp.sp_r_a_tov);
        if (r_a_tov > rdata->r_a_tov)
                rdata->r_a_tov = r_a_tov;

        if (rdata->ids.port_name < lport->wwpn)
                fc_rport_enter_plogi(rdata);
        else
                fc_rport_state_enter(rdata, RPORT_ST_PLOGI_WAIT);
out:
        fc_frame_free(fp);
err:
        mutex_unlock(&rdata->rp_mutex);
put:
        kref_put(&rdata->kref, lport->tt.rport_destroy);
        return;
bad:
        fc_rport_error_retry(rdata, fp);
        goto out;
}

/**
 * fc_rport_enter_flogi() - Send a FLOGI request to the remote port for p-mp
 * @rdata: The remote port to send a FLOGI to
 */
static void fc_rport_enter_flogi(struct fc_rport_priv *rdata)
{
        struct fc_lport *lport = rdata->local_port;
        struct fc_frame *fp;

        lockdep_assert_held(&rdata->rp_mutex);

        if (!lport->point_to_multipoint)
                return fc_rport_enter_plogi(rdata);

        FC_RPORT_DBG(rdata, "Entered FLOGI state from %s state\n",
                     fc_rport_state(rdata));

        fc_rport_state_enter(rdata, RPORT_ST_FLOGI);

        fp = fc_frame_alloc(lport, sizeof(struct fc_els_flogi));
        if (!fp)
                return fc_rport_error_retry(rdata, fp);

        if (!lport->tt.elsct_send(lport, rdata->ids.port_id, fp, ELS_FLOGI,
                                  fc_rport_flogi_resp, rdata,
                                  2 * lport->r_a_tov))
                fc_rport_error_retry(rdata, NULL);
        else
                kref_get(&rdata->kref);
}

/**
 * fc_rport_recv_flogi_req() - Handle Fabric Login (FLOGI) request in p-mp mode
 * @lport: The local port that received the PLOGI request
 * @rx_fp: The PLOGI request frame
 */
static void fc_rport_recv_flogi_req(struct fc_lport *lport,
                                    struct fc_frame *rx_fp)
{
        struct fc_disc *disc;
        struct fc_els_flogi *flp;
        struct fc_rport_priv *rdata;
        struct fc_frame *fp = rx_fp;
        struct fc_seq_els_data rjt_data;
        u32 sid;

        sid = fc_frame_sid(fp);

        FC_RPORT_ID_DBG(lport, sid, "Received FLOGI request\n");

        disc = &lport->disc;
        if (!lport->point_to_multipoint) {
                rjt_data.reason = ELS_RJT_UNSUP;
                rjt_data.explan = ELS_EXPL_NONE;
                goto reject;
        }

        flp = fc_frame_payload_get(fp, sizeof(*flp));
        if (!flp) {
                rjt_data.reason = ELS_RJT_LOGIC;
                rjt_data.explan = ELS_EXPL_INV_LEN;
                goto reject;
        }

        rdata = lport->tt.rport_lookup(lport, sid);
        if (!rdata) {
                rjt_data.reason = ELS_RJT_FIP;
                rjt_data.explan = ELS_EXPL_NOT_NEIGHBOR;
                goto reject;
        }
        mutex_lock(&rdata->rp_mutex);

        FC_RPORT_DBG(rdata, "Received FLOGI in %s state\n",
                     fc_rport_state(rdata));

        switch (rdata->rp_state) {
        case RPORT_ST_INIT:
                /*
                 * If received the FLOGI request on RPORT which is INIT state
                 * (means not transition to FLOGI either fc_rport timeout
                 * function didn;t trigger or this end hasn;t received
                 * beacon yet from other end. In that case only, allow RPORT
                 * state machine to continue, otherwise fall through which
                 * causes the code to send reject response.
                 * NOTE; Not checking for FIP->state such as VNMP_UP or
                 * VNMP_CLAIM because if FIP state is not one of those,
                 * RPORT wouldn;t have created and 'rport_lookup' would have
                 * failed anyway in that case.
                 */
                if (lport->point_to_multipoint)
                        break;
        case RPORT_ST_DELETE:
                mutex_unlock(&rdata->rp_mutex);
                rjt_data.reason = ELS_RJT_FIP;
                rjt_data.explan = ELS_EXPL_NOT_NEIGHBOR;
                goto reject_put;
        case RPORT_ST_FLOGI:
        case RPORT_ST_PLOGI_WAIT:
        case RPORT_ST_PLOGI:
                break;
        case RPORT_ST_PRLI:
        case RPORT_ST_RTV:
        case RPORT_ST_READY:
        case RPORT_ST_ADISC:
                /*
                 * Set the remote port to be deleted and to then restart.
                 * This queues work to be sure exchanges are reset.
                 */
                fc_rport_enter_delete(rdata, RPORT_EV_LOGO);
                mutex_unlock(&rdata->rp_mutex);
                rjt_data.reason = ELS_RJT_BUSY;
                rjt_data.explan = ELS_EXPL_NONE;
                goto reject_put;
        }
        if (fc_rport_login_complete(rdata, fp)) {
                mutex_unlock(&rdata->rp_mutex);
                rjt_data.reason = ELS_RJT_LOGIC;
                rjt_data.explan = ELS_EXPL_NONE;
                goto reject_put;
        }

        fp = fc_frame_alloc(lport, sizeof(*flp));
        if (!fp)
                goto out;

        fc_flogi_fill(lport, fp);
        flp = fc_frame_payload_get(fp, sizeof(*flp));
        flp->fl_cmd = ELS_LS_ACC;

        fc_fill_reply_hdr(fp, rx_fp, FC_RCTL_ELS_REP, 0);
        lport->tt.frame_send(lport, fp);

        /*
         * Do not proceed with the state machine if our
         * FLOGI has crossed with an FLOGI from the
         * remote port; wait for the FLOGI response instead.
         */
        if (rdata->rp_state != RPORT_ST_FLOGI) {
                if (rdata->ids.port_name < lport->wwpn)
                        fc_rport_enter_plogi(rdata);
                else
                        fc_rport_state_enter(rdata, RPORT_ST_PLOGI_WAIT);
        }
out:
        mutex_unlock(&rdata->rp_mutex);
        kref_put(&rdata->kref, lport->tt.rport_destroy);
        fc_frame_free(rx_fp);
        return;

reject_put:
        kref_put(&rdata->kref, lport->tt.rport_destroy);
reject:
        lport->tt.seq_els_rsp_send(rx_fp, ELS_LS_RJT, &rjt_data);
        fc_frame_free(rx_fp);
}

/**
 * fc_rport_plogi_resp() - Handler for ELS PLOGI responses
 * @sp:        The sequence the PLOGI is on
 * @fp:        The PLOGI response frame
 * @rdata_arg: The remote port that sent the PLOGI response
 *
 * Locking Note: This function will be called without the rport lock
 * held, but it will lock, call an _enter_* function or fc_rport_error
 * and then unlock the rport.
 */
static void fc_rport_plogi_resp(struct fc_seq *sp, struct fc_frame *fp,
                                void *rdata_arg)
{
        struct fc_rport_priv *rdata = rdata_arg;
        struct fc_lport *lport = rdata->local_port;
        struct fc_els_flogi *plp = NULL;
        u16 csp_seq;
        u16 cssp_seq;
        u8 op;

        mutex_lock(&rdata->rp_mutex);

        FC_RPORT_DBG(rdata, "Received a PLOGI %s\n", fc_els_resp_type(fp));

        if (rdata->rp_state != RPORT_ST_PLOGI) {
                FC_RPORT_DBG(rdata, "Received a PLOGI response, but in state "
                             "%s\n", fc_rport_state(rdata));
                if (IS_ERR(fp))
                        goto err;
                goto out;
        }

        if (IS_ERR(fp)) {
                fc_rport_error_retry(rdata, fp);
                goto err;
        }

        op = fc_frame_payload_op(fp);
        if (op == ELS_LS_ACC &&
            (plp = fc_frame_payload_get(fp, sizeof(*plp))) != NULL) {
                rdata->ids.port_name = get_unaligned_be64(&plp->fl_wwpn);
                rdata->ids.node_name = get_unaligned_be64(&plp->fl_wwnn);

                /* save plogi response sp_features for further reference */
                rdata->sp_features = ntohs(plp->fl_csp.sp_features);

                if (lport->point_to_multipoint)
                        fc_rport_login_complete(rdata, fp);
                csp_seq = ntohs(plp->fl_csp.sp_tot_seq);
                cssp_seq = ntohs(plp->fl_cssp[3 - 1].cp_con_seq);
                if (cssp_seq < csp_seq)
                        csp_seq = cssp_seq;
                rdata->max_seq = csp_seq;
                rdata->maxframe_size = fc_plogi_get_maxframe(plp, lport->mfs);
                fc_rport_enter_prli(rdata);
        } else
                fc_rport_error_retry(rdata, fp);

out:
        fc_frame_free(fp);
err:
        mutex_unlock(&rdata->rp_mutex);
        kref_put(&rdata->kref, lport->tt.rport_destroy);
}

/**
 * fc_rport_enter_plogi() - Send Port Login (PLOGI) request
 * @rdata: The remote port to send a PLOGI to
 */
static void fc_rport_enter_plogi(struct fc_rport_priv *rdata)
{
        struct fc_lport *lport = rdata->local_port;
        struct fc_frame *fp;

        lockdep_assert_held(&rdata->rp_mutex);

        FC_RPORT_DBG(rdata, "Port entered PLOGI state from %s state\n",
                     fc_rport_state(rdata));

        fc_rport_state_enter(rdata, RPORT_ST_PLOGI);

        rdata->maxframe_size = FC_MIN_MAX_PAYLOAD;
        fp = fc_frame_alloc(lport, sizeof(struct fc_els_flogi));
        if (!fp) {
                FC_RPORT_DBG(rdata, "%s frame alloc failed\n", __func__);
                fc_rport_error_retry(rdata, fp);
                return;
        }
        rdata->e_d_tov = lport->e_d_tov;

        if (!lport->tt.elsct_send(lport, rdata->ids.port_id, fp, ELS_PLOGI,
                                  fc_rport_plogi_resp, rdata,
                                  2 * lport->r_a_tov))
                fc_rport_error_retry(rdata, NULL);
        else
                kref_get(&rdata->kref);
}

/**
 * fc_rport_prli_resp() - Process Login (PRLI) response handler
 * @sp:        The sequence the PRLI response was on
 * @fp:        The PRLI response frame
 * @rdata_arg: The remote port that sent the PRLI response
 *
 * Locking Note: This function will be called without the rport lock
 * held, but it will lock, call an _enter_* function or fc_rport_error
 * and then unlock the rport.
 */
static void fc_rport_prli_resp(struct fc_seq *sp, struct fc_frame *fp,
                               void *rdata_arg)
{
        struct fc_rport_priv *rdata = rdata_arg;
        struct {
                struct fc_els_prli prli;
                struct fc_els_spp spp;
        } *pp;
        struct fc_els_spp temp_spp;
        struct fc4_prov *prov;

        u32 roles = FC_RPORT_ROLE_UNKNOWN;
        u32 fcp_parm = 0;
        u8 op;
        u8 resp_code = 0;

        mutex_lock(&rdata->rp_mutex);

        FC_RPORT_DBG(rdata, "Received a PRLI %s\n", fc_els_resp_type(fp));

        if (rdata->rp_state != RPORT_ST_PRLI) {
                FC_RPORT_DBG(rdata, "Received a PRLI response, but in state "
                             "%s\n", fc_rport_state(rdata));
                if (IS_ERR(fp))
                        goto err;
                goto out;
        }

        if (IS_ERR(fp)) {
                fc_rport_error_retry(rdata, fp);
                goto err;
        }

        /* reinitialize remote port roles */
        rdata->ids.roles = FC_RPORT_ROLE_UNKNOWN;

        op = fc_frame_payload_op(fp);
        if (op == ELS_LS_ACC) {
                pp = fc_frame_payload_get(fp, sizeof(*pp));
                if (!pp) {
                        fc_rport_error_retry(rdata, NULL);
                        goto out;
                }

                resp_code = (pp->spp.spp_flags & FC_SPP_RESP_MASK);
                FC_RPORT_DBG(rdata, "PRLI spp_flags = 0x%x\n",
                             pp->spp.spp_flags);
                rdata->spp_type = pp->spp.spp_type;
                if (resp_code != FC_SPP_RESP_ACK) {
                        if (resp_code == FC_SPP_RESP_CONF)
                                fc_rport_error(rdata, fp);
                        else
                                fc_rport_error_retry(rdata, fp);
                        goto out;
                }
                if (pp->prli.prli_spp_len < sizeof(pp->spp)) {
                        fc_rport_error_retry(rdata, NULL);
                        goto out;
                }

                fcp_parm = ntohl(pp->spp.spp_params);
                if (fcp_parm & FCP_SPPF_RETRY)
                        rdata->flags |= FC_RP_FLAGS_RETRY;
                if (fcp_parm & FCP_SPPF_CONF_COMPL)
                        rdata->flags |= FC_RP_FLAGS_CONF_REQ;

                prov = fc_passive_prov[FC_TYPE_FCP];
                if (prov) {
                        memset(&temp_spp, 0, sizeof(temp_spp));
                        prov->prli(rdata, pp->prli.prli_spp_len,
                                   &pp->spp, &temp_spp);
                }

                rdata->supported_classes = FC_COS_CLASS3;
                if (fcp_parm & FCP_SPPF_INIT_FCN)
                        roles |= FC_RPORT_ROLE_FCP_INITIATOR;
                if (fcp_parm & FCP_SPPF_TARG_FCN)
                        roles |= FC_RPORT_ROLE_FCP_TARGET;

                rdata->ids.roles = roles;
                fc_rport_enter_rtv(rdata);

        } else {
                FC_RPORT_DBG(rdata, "Bad ELS response for PRLI command\n");
                fc_rport_error_retry(rdata, fp);
        }

out:
        fc_frame_free(fp);
err:
        mutex_unlock(&rdata->rp_mutex);
        kref_put(&rdata->kref, rdata->local_port->tt.rport_destroy);
}

/**
 * fc_rport_enter_prli() - Send Process Login (PRLI) request
 * @rdata: The remote port to send the PRLI request to
 */
static void fc_rport_enter_prli(struct fc_rport_priv *rdata)
{
        struct fc_lport *lport = rdata->local_port;
        struct {
                struct fc_els_prli prli;
                struct fc_els_spp spp;
        } *pp;
        struct fc_frame *fp;
        struct fc4_prov *prov;

        lockdep_assert_held(&rdata->rp_mutex);

        /*
         * If the rport is one of the well known addresses
         * we skip PRLI and RTV and go straight to READY.
         */
        if (rdata->ids.port_id >= FC_FID_DOM_MGR) {
                fc_rport_enter_ready(rdata);
                return;
        }

        FC_RPORT_DBG(rdata, "Port entered PRLI state from %s state\n",
                     fc_rport_state(rdata));

        fc_rport_state_enter(rdata, RPORT_ST_PRLI);

        fp = fc_frame_alloc(lport, sizeof(*pp));
        if (!fp) {
                fc_rport_error_retry(rdata, fp);
                return;
        }

        fc_prli_fill(lport, fp);

        prov = fc_passive_prov[FC_TYPE_FCP];
        if (prov) {
                pp = fc_frame_payload_get(fp, sizeof(*pp));
                prov->prli(rdata, sizeof(pp->spp), NULL, &pp->spp);
        }

        fc_fill_fc_hdr(fp, FC_RCTL_ELS_REQ, rdata->ids.port_id,
                       fc_host_port_id(lport->host), FC_TYPE_ELS,
                       FC_FC_FIRST_SEQ | FC_FC_END_SEQ | FC_FC_SEQ_INIT, 0);

        if (!lport->tt.exch_seq_send(lport, fp, fc_rport_prli_resp,
                                    NULL, rdata, 2 * lport->r_a_tov))
                fc_rport_error_retry(rdata, NULL);
        else
                kref_get(&rdata->kref);
}

/**
 * fc_rport_els_rtv_resp() - Handler for Request Timeout Value (RTV) responses
 * @sp:        The sequence the RTV was on
 * @fp:        The RTV response frame
 * @rdata_arg: The remote port that sent the RTV response
 *
 * Many targets don't seem to support this.
 *
 * Locking Note: This function will be called without the rport lock
 * held, but it will lock, call an _enter_* function or fc_rport_error
 * and then unlock the rport.
 */
static void fc_rport_rtv_resp(struct fc_seq *sp, struct fc_frame *fp,
                              void *rdata_arg)
{
        struct fc_rport_priv *rdata = rdata_arg;
        u8 op;

        mutex_lock(&rdata->rp_mutex);

        FC_RPORT_DBG(rdata, "Received a RTV %s\n", fc_els_resp_type(fp));

        if (rdata->rp_state != RPORT_ST_RTV) {
                FC_RPORT_DBG(rdata, "Received a RTV response, but in state "
                             "%s\n", fc_rport_state(rdata));
                if (IS_ERR(fp))
                        goto err;
                goto out;
        }

        if (IS_ERR(fp)) {
                fc_rport_error(rdata, fp);
                goto err;
        }

        op = fc_frame_payload_op(fp);
        if (op == ELS_LS_ACC) {
                struct fc_els_rtv_acc *rtv;
                u32 toq;
                u32 tov;

                rtv = fc_frame_payload_get(fp, sizeof(*rtv));
                if (rtv) {
                        toq = ntohl(rtv->rtv_toq);
                        tov = ntohl(rtv->rtv_r_a_tov);
                        if (tov == 0)
                                tov = 1;
                        rdata->r_a_tov = tov;
                        tov = ntohl(rtv->rtv_e_d_tov);
                        if (toq & FC_ELS_RTV_EDRES)
                                tov /= 1000000;
                        if (tov == 0)
                                tov = 1;
                        rdata->e_d_tov = tov;
                }
        }

        fc_rport_enter_ready(rdata);

out:
        fc_frame_free(fp);
err:
        mutex_unlock(&rdata->rp_mutex);
        kref_put(&rdata->kref, rdata->local_port->tt.rport_destroy);
}

/**
 * fc_rport_enter_rtv() - Send Request Timeout Value (RTV) request
 * @rdata: The remote port to send the RTV request to
 */
static void fc_rport_enter_rtv(struct fc_rport_priv *rdata)
{
        struct fc_frame *fp;
        struct fc_lport *lport = rdata->local_port;

        lockdep_assert_held(&rdata->rp_mutex);

        FC_RPORT_DBG(rdata, "Port entered RTV state from %s state\n",
                     fc_rport_state(rdata));

        fc_rport_state_enter(rdata, RPORT_ST_RTV);

        fp = fc_frame_alloc(lport, sizeof(struct fc_els_rtv));
        if (!fp) {
                fc_rport_error_retry(rdata, fp);
                return;
        }

        if (!lport->tt.elsct_send(lport, rdata->ids.port_id, fp, ELS_RTV,
                                  fc_rport_rtv_resp, rdata,
                                  2 * lport->r_a_tov))
                fc_rport_error_retry(rdata, NULL);
        else
                kref_get(&rdata->kref);
}

/**
 * fc_rport_logo_resp() - Handler for logout (LOGO) responses
 * @sp:        The sequence the LOGO was on
 * @fp:        The LOGO response frame
 * @lport_arg: The local port
 */
static void fc_rport_logo_resp(struct fc_seq *sp, struct fc_frame *fp,
                               void *lport_arg)
{
        struct fc_lport *lport = lport_arg;

        FC_RPORT_ID_DBG(lport, fc_seq_exch(sp)->did,
                        "Received a LOGO %s\n", fc_els_resp_type(fp));
        if (IS_ERR(fp))
                return;
        fc_frame_free(fp);
}

/**
 * fc_rport_enter_logo() - Send a logout (LOGO) request
 * @rdata: The remote port to send the LOGO request to
 */
static void fc_rport_enter_logo(struct fc_rport_priv *rdata)
{
        struct fc_lport *lport = rdata->local_port;
        struct fc_frame *fp;

        lockdep_assert_held(&rdata->rp_mutex);

        FC_RPORT_DBG(rdata, "Port sending LOGO from %s state\n",
                     fc_rport_state(rdata));

        fp = fc_frame_alloc(lport, sizeof(struct fc_els_logo));
        if (!fp)
                return;
        (void)lport->tt.elsct_send(lport, rdata->ids.port_id, fp, ELS_LOGO,
                                   fc_rport_logo_resp, lport, 0);
}

/**
 * fc_rport_els_adisc_resp() - Handler for Address Discovery (ADISC) responses
 * @sp:        The sequence the ADISC response was on
 * @fp:        The ADISC response frame
 * @rdata_arg: The remote port that sent the ADISC response
 *
 * Locking Note: This function will be called without the rport lock
 * held, but it will lock, call an _enter_* function or fc_rport_error
 * and then unlock the rport.
 */
static void fc_rport_adisc_resp(struct fc_seq *sp, struct fc_frame *fp,
                                void *rdata_arg)
{
        struct fc_rport_priv *rdata = rdata_arg;
        struct fc_els_adisc *adisc;
        u8 op;

        mutex_lock(&rdata->rp_mutex);

        FC_RPORT_DBG(rdata, "Received a ADISC response\n");

        if (rdata->rp_state != RPORT_ST_ADISC) {
                FC_RPORT_DBG(rdata, "Received a ADISC resp but in state %s\n",
                             fc_rport_state(rdata));
                if (IS_ERR(fp))
                        goto err;
                goto out;
        }

        if (IS_ERR(fp)) {
                fc_rport_error(rdata, fp);
                goto err;
        }

        /*
         * If address verification failed.  Consider us logged out of the rport.
         * Since the rport is still in discovery, we want to be
         * logged in, so go to PLOGI state.  Otherwise, go back to READY.
         */
        op = fc_frame_payload_op(fp);
        adisc = fc_frame_payload_get(fp, sizeof(*adisc));
        if (op != ELS_LS_ACC || !adisc ||
            ntoh24(adisc->adisc_port_id) != rdata->ids.port_id ||
            get_unaligned_be64(&adisc->adisc_wwpn) != rdata->ids.port_name ||
            get_unaligned_be64(&adisc->adisc_wwnn) != rdata->ids.node_name) {
                FC_RPORT_DBG(rdata, "ADISC error or mismatch\n");
                fc_rport_enter_flogi(rdata);
        } else {
                FC_RPORT_DBG(rdata, "ADISC OK\n");
                fc_rport_enter_ready(rdata);
        }
out:
        fc_frame_free(fp);
err:
        mutex_unlock(&rdata->rp_mutex);
        kref_put(&rdata->kref, rdata->local_port->tt.rport_destroy);
}

/**
 * fc_rport_enter_adisc() - Send Address Discover (ADISC) request
 * @rdata: The remote port to send the ADISC request to
 */
static void fc_rport_enter_adisc(struct fc_rport_priv *rdata)
{
        struct fc_lport *lport = rdata->local_port;
        struct fc_frame *fp;

        lockdep_assert_held(&rdata->rp_mutex);

        FC_RPORT_DBG(rdata, "sending ADISC from %s state\n",
                     fc_rport_state(rdata));

        fc_rport_state_enter(rdata, RPORT_ST_ADISC);

        fp = fc_frame_alloc(lport, sizeof(struct fc_els_adisc));
        if (!fp) {
                fc_rport_error_retry(rdata, fp);
                return;
        }
        if (!lport->tt.elsct_send(lport, rdata->ids.port_id, fp, ELS_ADISC,
                                  fc_rport_adisc_resp, rdata,
                                  2 * lport->r_a_tov))
                fc_rport_error_retry(rdata, NULL);
        else
                kref_get(&rdata->kref);
}

/**
 * fc_rport_recv_adisc_req() - Handler for Address Discovery (ADISC) requests
 * @rdata: The remote port that sent the ADISC request
 * @in_fp: The ADISC request frame
 */
static void fc_rport_recv_adisc_req(struct fc_rport_priv *rdata,
                                    struct fc_frame *in_fp)
{
        struct fc_lport *lport = rdata->local_port;
        struct fc_frame *fp;
        struct fc_els_adisc *adisc;
        struct fc_seq_els_data rjt_data;

        lockdep_assert_held(&rdata->rp_mutex);
        lockdep_assert_held(&lport->lp_mutex);

        FC_RPORT_DBG(rdata, "Received ADISC request\n");

        adisc = fc_frame_payload_get(in_fp, sizeof(*adisc));
        if (!adisc) {
                rjt_data.reason = ELS_RJT_PROT;
                rjt_data.explan = ELS_EXPL_INV_LEN;
                lport->tt.seq_els_rsp_send(in_fp, ELS_LS_RJT, &rjt_data);
                goto drop;
        }

        fp = fc_frame_alloc(lport, sizeof(*adisc));
        if (!fp)
                goto drop;
        fc_adisc_fill(lport, fp);
        adisc = fc_frame_payload_get(fp, sizeof(*adisc));
        adisc->adisc_cmd = ELS_LS_ACC;
        fc_fill_reply_hdr(fp, in_fp, FC_RCTL_ELS_REP, 0);
        lport->tt.frame_send(lport, fp);
drop:
        fc_frame_free(in_fp);
}

/**
 * fc_rport_recv_rls_req() - Handle received Read Link Status request
 * @rdata: The remote port that sent the RLS request
 * @rx_fp: The PRLI request frame
 */
static void fc_rport_recv_rls_req(struct fc_rport_priv *rdata,
                                  struct fc_frame *rx_fp)

{
        struct fc_lport *lport = rdata->local_port;
        struct fc_frame *fp;
        struct fc_els_rls *rls;
        struct fc_els_rls_resp *rsp;
        struct fc_els_lesb *lesb;
        struct fc_seq_els_data rjt_data;
        struct fc_host_statistics *hst;

        lockdep_assert_held(&rdata->rp_mutex);

        FC_RPORT_DBG(rdata, "Received RLS request while in state %s\n",
                     fc_rport_state(rdata));

        rls = fc_frame_payload_get(rx_fp, sizeof(*rls));
        if (!rls) {
                rjt_data.reason = ELS_RJT_PROT;
                rjt_data.explan = ELS_EXPL_INV_LEN;
                goto out_rjt;
        }

        fp = fc_frame_alloc(lport, sizeof(*rsp));
        if (!fp) {
                rjt_data.reason = ELS_RJT_UNAB;
                rjt_data.explan = ELS_EXPL_INSUF_RES;
                goto out_rjt;
        }

        rsp = fc_frame_payload_get(fp, sizeof(*rsp));
        memset(rsp, 0, sizeof(*rsp));
        rsp->rls_cmd = ELS_LS_ACC;
        lesb = &rsp->rls_lesb;
        if (lport->tt.get_lesb) {
                /* get LESB from LLD if it supports it */
                lport->tt.get_lesb(lport, lesb);
        } else {
                fc_get_host_stats(lport->host);
                hst = &lport->host_stats;
                lesb->lesb_link_fail = htonl(hst->link_failure_count);
                lesb->lesb_sync_loss = htonl(hst->loss_of_sync_count);
                lesb->lesb_sig_loss = htonl(hst->loss_of_signal_count);
                lesb->lesb_prim_err = htonl(hst->prim_seq_protocol_err_count);
                lesb->lesb_inv_word = htonl(hst->invalid_tx_word_count);
                lesb->lesb_inv_crc = htonl(hst->invalid_crc_count);
        }

        fc_fill_reply_hdr(fp, rx_fp, FC_RCTL_ELS_REP, 0);
        lport->tt.frame_send(lport, fp);
        goto out;

out_rjt:
        lport->tt.seq_els_rsp_send(rx_fp, ELS_LS_RJT, &rjt_data);
out:
        fc_frame_free(rx_fp);
}

/**
 * fc_rport_recv_els_req() - Handler for validated ELS requests
 * @lport: The local port that received the ELS request
 * @fp:    The ELS request frame
 *
 * Handle incoming ELS requests that require port login.
 * The ELS opcode has already been validated by the caller.
 */
static void fc_rport_recv_els_req(struct fc_lport *lport, struct fc_frame *fp)
{
        struct fc_rport_priv *rdata;
        struct fc_seq_els_data els_data;

        lockdep_assert_held(&lport->lp_mutex);

        rdata = lport->tt.rport_lookup(lport, fc_frame_sid(fp));
        if (!rdata)
                goto reject;

        mutex_lock(&rdata->rp_mutex);

        switch (rdata->rp_state) {
        case RPORT_ST_PRLI:
        case RPORT_ST_RTV:
        case RPORT_ST_READY:
        case RPORT_ST_ADISC:
                break;
        default:
                mutex_unlock(&rdata->rp_mutex);
                kref_put(&rdata->kref, lport->tt.rport_destroy);
                goto reject;
        }

        switch (fc_frame_payload_op(fp)) {
        case ELS_PRLI:
                fc_rport_recv_prli_req(rdata, fp);
                break;
        case ELS_PRLO:
                fc_rport_recv_prlo_req(rdata, fp);
                break;
        case ELS_ADISC:
                fc_rport_recv_adisc_req(rdata, fp);
                break;
        case ELS_RRQ:
                lport->tt.seq_els_rsp_send(fp, ELS_RRQ, NULL);
                fc_frame_free(fp);
                break;
        case ELS_REC:
                lport->tt.seq_els_rsp_send(fp, ELS_REC, NULL);
                fc_frame_free(fp);
                break;
        case ELS_RLS:
                fc_rport_recv_rls_req(rdata, fp);
                break;
        default:
                fc_frame_free(fp);      /* can't happen */
                break;
        }

        mutex_unlock(&rdata->rp_mutex);
        kref_put(&rdata->kref, rdata->local_port->tt.rport_destroy);
        return;

reject:
        els_data.reason = ELS_RJT_UNAB;
        els_data.explan = ELS_EXPL_PLOGI_REQD;
        lport->tt.seq_els_rsp_send(fp, ELS_LS_RJT, &els_data);
        fc_frame_free(fp);
}

/**
 * fc_rport_recv_req() - Handler for requests
 * @lport: The local port that received the request
 * @fp:    The request frame
 */
static void fc_rport_recv_req(struct fc_lport *lport, struct fc_frame *fp)
{
        struct fc_seq_els_data els_data;

        lockdep_assert_held(&lport->lp_mutex);

        /*
         * Handle FLOGI, PLOGI and LOGO requests separately, since they
         * don't require prior login.
         * Check for unsupported opcodes first and reject them.
         * For some ops, it would be incorrect to reject with "PLOGI required".
         */
        switch (fc_frame_payload_op(fp)) {
        case ELS_FLOGI:
                fc_rport_recv_flogi_req(lport, fp);
                break;
        case ELS_PLOGI:
                fc_rport_recv_plogi_req(lport, fp);
                break;
        case ELS_LOGO:
                fc_rport_recv_logo_req(lport, fp);
                break;
        case ELS_PRLI:
        case ELS_PRLO:
        case ELS_ADISC:
        case ELS_RRQ:
        case ELS_REC:
        case ELS_RLS:
                fc_rport_recv_els_req(lport, fp);
                break;
        default:
                els_data.reason = ELS_RJT_UNSUP;
                els_data.explan = ELS_EXPL_NONE;
                lport->tt.seq_els_rsp_send(fp, ELS_LS_RJT, &els_data);
                fc_frame_free(fp);
                break;
        }
}

/**
 * fc_rport_recv_plogi_req() - Handler for Port Login (PLOGI) requests
 * @lport: The local port that received the PLOGI request
 * @rx_fp: The PLOGI request frame
 */
static void fc_rport_recv_plogi_req(struct fc_lport *lport,
                                    struct fc_frame *rx_fp)
{
        struct fc_disc *disc;
        struct fc_rport_priv *rdata;
        struct fc_frame *fp = rx_fp;
        struct fc_els_flogi *pl;
        struct fc_seq_els_data rjt_data;
        u32 sid;

        lockdep_assert_held(&lport->lp_mutex);

        sid = fc_frame_sid(fp);

        FC_RPORT_ID_DBG(lport, sid, "Received PLOGI request\n");

        pl = fc_frame_payload_get(fp, sizeof(*pl));
        if (!pl) {
                FC_RPORT_ID_DBG(lport, sid, "Received PLOGI too short\n");
                rjt_data.reason = ELS_RJT_PROT;
                rjt_data.explan = ELS_EXPL_INV_LEN;
                goto reject;
        }

        disc = &lport->disc;
        mutex_lock(&disc->disc_mutex);
        rdata = lport->tt.rport_create(lport, sid);
        if (!rdata) {
                mutex_unlock(&disc->disc_mutex);
                rjt_data.reason = ELS_RJT_UNAB;
                rjt_data.explan = ELS_EXPL_INSUF_RES;
                goto reject;
        }

        mutex_lock(&rdata->rp_mutex);
        mutex_unlock(&disc->disc_mutex);

        rdata->ids.port_name = get_unaligned_be64(&pl->fl_wwpn);
        rdata->ids.node_name = get_unaligned_be64(&pl->fl_wwnn);

        /*
         * If the rport was just created, possibly due to the incoming PLOGI,
         * set the state appropriately and accept the PLOGI.
         *
         * If we had also sent a PLOGI, and if the received PLOGI is from a
         * higher WWPN, we accept it, otherwise an LS_RJT is sent with reason
         * "command already in progress".
         *
         * XXX TBD: If the session was ready before, the PLOGI should result in
         * all outstanding exchanges being reset.
         */
        switch (rdata->rp_state) {
        case RPORT_ST_INIT:
                FC_RPORT_DBG(rdata, "Received PLOGI in INIT state\n");
                break;
        case RPORT_ST_PLOGI_WAIT:
                FC_RPORT_DBG(rdata, "Received PLOGI in PLOGI_WAIT state\n");
                break;
        case RPORT_ST_PLOGI:
                FC_RPORT_DBG(rdata, "Received PLOGI in PLOGI state\n");
                if (rdata->ids.port_name < lport->wwpn) {
                        mutex_unlock(&rdata->rp_mutex);
                        rjt_data.reason = ELS_RJT_INPROG;
                        rjt_data.explan = ELS_EXPL_NONE;
                        goto reject;
                }
                break;
        case RPORT_ST_PRLI:
        case RPORT_ST_RTV:
        case RPORT_ST_READY:
        case RPORT_ST_ADISC:
                FC_RPORT_DBG(rdata, "Received PLOGI in logged-in state %d "
                             "- ignored for now\n", rdata->rp_state);
                /* XXX TBD - should reset */
                break;
        case RPORT_ST_FLOGI:
        case RPORT_ST_DELETE:
                FC_RPORT_DBG(rdata, "Received PLOGI in state %s - send busy\n",
                             fc_rport_state(rdata));
                mutex_unlock(&rdata->rp_mutex);
                rjt_data.reason = ELS_RJT_BUSY;
                rjt_data.explan = ELS_EXPL_NONE;
                goto reject;
        }

        /*
         * Get session payload size from incoming PLOGI.
         */
        rdata->maxframe_size = fc_plogi_get_maxframe(pl, lport->mfs);

        /*
         * Send LS_ACC.  If this fails, the originator should retry.
         */
        fp = fc_frame_alloc(lport, sizeof(*pl));
        if (!fp)
                goto out;

        fc_plogi_fill(lport, fp, ELS_LS_ACC);
        fc_fill_reply_hdr(fp, rx_fp, FC_RCTL_ELS_REP, 0);
        lport->tt.frame_send(lport, fp);
        fc_rport_enter_prli(rdata);
out:
        mutex_unlock(&rdata->rp_mutex);
        fc_frame_free(rx_fp);
        return;

reject:
        lport->tt.seq_els_rsp_send(fp, ELS_LS_RJT, &rjt_data);
        fc_frame_free(fp);
}

/**
 * fc_rport_recv_prli_req() - Handler for process login (PRLI) requests
 * @rdata: The remote port that sent the PRLI request
 * @rx_fp: The PRLI request frame
 */
static void fc_rport_recv_prli_req(struct fc_rport_priv *rdata,
                                   struct fc_frame *rx_fp)
{
        struct fc_lport *lport = rdata->local_port;
        struct fc_frame *fp;
        struct {
                struct fc_els_prli prli;
                struct fc_els_spp spp;
        } *pp;
        struct fc_els_spp *rspp;        /* request service param page */
        struct fc_els_spp *spp; /* response spp */
        unsigned int len;
        unsigned int plen;
        enum fc_els_spp_resp resp;
        enum fc_els_spp_resp passive;
        struct fc_seq_els_data rjt_data;
        struct fc4_prov *prov;

        lockdep_assert_held(&rdata->rp_mutex);

        FC_RPORT_DBG(rdata, "Received PRLI request while in state %s\n",
                     fc_rport_state(rdata));

        len = fr_len(rx_fp) - sizeof(struct fc_frame_header);
        pp = fc_frame_payload_get(rx_fp, sizeof(*pp));
        if (!pp)
                goto reject_len;
        plen = ntohs(pp->prli.prli_len);
        if ((plen % 4) != 0 || plen > len || plen < 16)
                goto reject_len;
        if (plen < len)
                len = plen;
        plen = pp->prli.prli_spp_len;
        if ((plen % 4) != 0 || plen < sizeof(*spp) ||
            plen > len || len < sizeof(*pp) || plen < 12)
                goto reject_len;
        rspp = &pp->spp;

        fp = fc_frame_alloc(lport, len);
        if (!fp) {
                rjt_data.reason = ELS_RJT_UNAB;
                rjt_data.explan = ELS_EXPL_INSUF_RES;
                goto reject;
        }
        pp = fc_frame_payload_get(fp, len);
        WARN_ON(!pp);
        memset(pp, 0, len);
        pp->prli.prli_cmd = ELS_LS_ACC;
        pp->prli.prli_spp_len = plen;
        pp->prli.prli_len = htons(len);
        len -= sizeof(struct fc_els_prli);

        /*
         * Go through all the service parameter pages and build
         * response.  If plen indicates longer SPP than standard,
         * use that.  The entire response has been pre-cleared above.
         */
        spp = &pp->spp;
        mutex_lock(&fc_prov_mutex);
        while (len >= plen) {
                rdata->spp_type = rspp->spp_type;
                spp->spp_type = rspp->spp_type;
                spp->spp_type_ext = rspp->spp_type_ext;
                resp = 0;

                if (rspp->spp_type < FC_FC4_PROV_SIZE) {
                        prov = fc_active_prov[rspp->spp_type];
                        if (prov)
                                resp = prov->prli(rdata, plen, rspp, spp);
                        prov = fc_passive_prov[rspp->spp_type];
                        if (prov) {
                                passive = prov->prli(rdata, plen, rspp, spp);
                                if (!resp || passive == FC_SPP_RESP_ACK)
                                        resp = passive;
                        }
                }
                if (!resp) {
                        if (spp->spp_flags & FC_SPP_EST_IMG_PAIR)
                                resp |= FC_SPP_RESP_CONF;
                        else
                                resp |= FC_SPP_RESP_INVL;
                }
                spp->spp_flags |= resp;
                len -= plen;
                rspp = (struct fc_els_spp *)((char *)rspp + plen);
                spp = (struct fc_els_spp *)((char *)spp + plen);
        }
        mutex_unlock(&fc_prov_mutex);

        /*
         * Send LS_ACC.  If this fails, the originator should retry.
         */
        fc_fill_reply_hdr(fp, rx_fp, FC_RCTL_ELS_REP, 0);
        lport->tt.frame_send(lport, fp);

        switch (rdata->rp_state) {
        case RPORT_ST_PRLI:
                fc_rport_enter_ready(rdata);
                break;
        default:
                break;
        }
        goto drop;

reject_len:
        rjt_data.reason = ELS_RJT_PROT;
        rjt_data.explan = ELS_EXPL_INV_LEN;
reject:
        lport->tt.seq_els_rsp_send(rx_fp, ELS_LS_RJT, &rjt_data);
drop:
        fc_frame_free(rx_fp);
}

/**
 * fc_rport_recv_prlo_req() - Handler for process logout (PRLO) requests
 * @rdata: The remote port that sent the PRLO request
 * @rx_fp: The PRLO request frame
 */
static void fc_rport_recv_prlo_req(struct fc_rport_priv *rdata,
                                   struct fc_frame *rx_fp)
{
        struct fc_lport *lport = rdata->local_port;
        struct fc_frame *fp;
        struct {
                struct fc_els_prlo prlo;
                struct fc_els_spp spp;
        } *pp;
        struct fc_els_spp *rspp;        /* request service param page */
        struct fc_els_spp *spp;         /* response spp */
        unsigned int len;
        unsigned int plen;
        struct fc_seq_els_data rjt_data;

        lockdep_assert_held(&rdata->rp_mutex);

        FC_RPORT_DBG(rdata, "Received PRLO request while in state %s\n",
                     fc_rport_state(rdata));

        len = fr_len(rx_fp) - sizeof(struct fc_frame_header);
        pp = fc_frame_payload_get(rx_fp, sizeof(*pp));
        if (!pp)
                goto reject_len;
        plen = ntohs(pp->prlo.prlo_len);
        if (plen != 20)
                goto reject_len;
        if (plen < len)
                len = plen;

        rspp = &pp->spp;

        fp = fc_frame_alloc(lport, len);
        if (!fp) {
                rjt_data.reason = ELS_RJT_UNAB;
                rjt_data.explan = ELS_EXPL_INSUF_RES;
                goto reject;
        }

        pp = fc_frame_payload_get(fp, len);
        WARN_ON(!pp);
        memset(pp, 0, len);
        pp->prlo.prlo_cmd = ELS_LS_ACC;
        pp->prlo.prlo_obs = 0x10;
        pp->prlo.prlo_len = htons(len);
        spp = &pp->spp;
        spp->spp_type = rspp->spp_type;
        spp->spp_type_ext = rspp->spp_type_ext;
        spp->spp_flags = FC_SPP_RESP_ACK;

        fc_rport_enter_delete(rdata, RPORT_EV_LOGO);

        fc_fill_reply_hdr(fp, rx_fp, FC_RCTL_ELS_REP, 0);
        lport->tt.frame_send(lport, fp);
        goto drop;

reject_len:
        rjt_data.reason = ELS_RJT_PROT;
        rjt_data.explan = ELS_EXPL_INV_LEN;
reject:
        lport->tt.seq_els_rsp_send(rx_fp, ELS_LS_RJT, &rjt_data);
drop:
        fc_frame_free(rx_fp);
}

/**
 * fc_rport_recv_logo_req() - Handler for logout (LOGO) requests
 * @lport: The local port that received the LOGO request
 * @fp:    The LOGO request frame
 */
static void fc_rport_recv_logo_req(struct fc_lport *lport, struct fc_frame *fp)
{
        struct fc_rport_priv *rdata;
        u32 sid;

        lockdep_assert_held(&lport->lp_mutex);

        lport->tt.seq_els_rsp_send(fp, ELS_LS_ACC, NULL);

        sid = fc_frame_sid(fp);

        rdata = lport->tt.rport_lookup(lport, sid);
        if (rdata) {
                mutex_lock(&rdata->rp_mutex);
                FC_RPORT_DBG(rdata, "Received LOGO request while in state %s\n",
                             fc_rport_state(rdata));

                fc_rport_enter_delete(rdata, RPORT_EV_LOGO);
                mutex_unlock(&rdata->rp_mutex);
                kref_put(&rdata->kref, rdata->local_port->tt.rport_destroy);
        } else
                FC_RPORT_ID_DBG(lport, sid,
                                "Received LOGO from non-logged-in port\n");
        fc_frame_free(fp);
}

/**
 * fc_rport_flush_queue() - Flush the rport_event_queue
 */
static void fc_rport_flush_queue(void)
{
        flush_workqueue(rport_event_queue);
}

/**
 * fc_rport_init() - Initialize the remote port layer for a local port
 * @lport: The local port to initialize the remote port layer for
 */
int fc_rport_init(struct fc_lport *lport)
{
        if (!lport->tt.rport_lookup)
                lport->tt.rport_lookup = fc_rport_lookup;

        if (!lport->tt.rport_create)
                lport->tt.rport_create = fc_rport_create;

        if (!lport->tt.rport_login)
                lport->tt.rport_login = fc_rport_login;

        if (!lport->tt.rport_logoff)
                lport->tt.rport_logoff = fc_rport_logoff;

        if (!lport->tt.rport_recv_req)
                lport->tt.rport_recv_req = fc_rport_recv_req;

        if (!lport->tt.rport_flush_queue)
                lport->tt.rport_flush_queue = fc_rport_flush_queue;

        if (!lport->tt.rport_destroy)
                lport->tt.rport_destroy = fc_rport_destroy;

        return 0;
}
EXPORT_SYMBOL(fc_rport_init);

/**
 * fc_rport_fcp_prli() - Handle incoming PRLI for the FCP initiator.
 * @rdata: remote port private
 * @spp_len: service parameter page length
 * @rspp: received service parameter page
 * @spp: response service parameter page
 *
 * Returns the value for the response code to be placed in spp_flags;
 * Returns 0 if not an initiator.
 */
static int fc_rport_fcp_prli(struct fc_rport_priv *rdata, u32 spp_len,
                             const struct fc_els_spp *rspp,
                             struct fc_els_spp *spp)
{
        struct fc_lport *lport = rdata->local_port;
        u32 fcp_parm;

        fcp_parm = ntohl(rspp->spp_params);
        rdata->ids.roles = FC_RPORT_ROLE_UNKNOWN;
        if (fcp_parm & FCP_SPPF_INIT_FCN)
                rdata->ids.roles |= FC_RPORT_ROLE_FCP_INITIATOR;
        if (fcp_parm & FCP_SPPF_TARG_FCN)
                rdata->ids.roles |= FC_RPORT_ROLE_FCP_TARGET;
        if (fcp_parm & FCP_SPPF_RETRY)
                rdata->flags |= FC_RP_FLAGS_RETRY;
        rdata->supported_classes = FC_COS_CLASS3;

        if (!(lport->service_params & FCP_SPPF_INIT_FCN))
                return 0;

        spp->spp_flags |= rspp->spp_flags & FC_SPP_EST_IMG_PAIR;

        /*
         * OR in our service parameters with other providers (target), if any.
         */
        fcp_parm = ntohl(spp->spp_params);
        spp->spp_params = htonl(fcp_parm | lport->service_params);
        return FC_SPP_RESP_ACK;
}

/*
 * FC-4 provider ops for FCP initiator.
 */
struct fc4_prov fc_rport_fcp_init = {
        .prli = fc_rport_fcp_prli,
};

/**
 * fc_rport_t0_prli() - Handle incoming PRLI parameters for type 0
 * @rdata: remote port private

 * @spp_len: service parameter page length
 * @rspp: received service parameter page
 * @spp: response service parameter page
 */
static int fc_rport_t0_prli(struct fc_rport_priv *rdata, u32 spp_len,
                            const struct fc_els_spp *rspp,
                            struct fc_els_spp *spp)
{
        if (rspp->spp_flags & FC_SPP_EST_IMG_PAIR)
                return FC_SPP_RESP_INVL;
        return FC_SPP_RESP_ACK;
}

/*
 * FC-4 provider ops for type 0 service parameters.
 *
 * This handles the special case of type 0 which is always successful
 * but doesn't do anything otherwise.
 */
struct fc4_prov fc_rport_t0_prov = {
        .prli = fc_rport_t0_prli,
};

/**
 * fc_setup_rport() - Initialize the rport_event_queue
 */
int fc_setup_rport(void)
{
        rport_event_queue = create_singlethread_workqueue("fc_rport_eq");
        if (!rport_event_queue)
                return -ENOMEM;
        return 0;
}

/**
 * fc_destroy_rport() - Destroy the rport_event_queue
 */
void fc_destroy_rport(void)
{
        destroy_workqueue(rport_event_queue);
}

/**
 * fc_rport_terminate_io() - Stop all outstanding I/O on a remote port
 * @rport: The remote port whose I/O should be terminated
 */
void fc_rport_terminate_io(struct fc_rport *rport)
{
        struct fc_rport_libfc_priv *rpriv = rport->dd_data;
        struct fc_lport *lport = rpriv->local_port;

        lport->tt.exch_mgr_reset(lport, 0, rport->port_id);
        lport->tt.exch_mgr_reset(lport, rport->port_id, 0);
}
EXPORT_SYMBOL(fc_rport_terminate_io);