[SCSI] libfc: fix rport error handling for login-required and invalid ops

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

/*
 * 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 heirarchy.
 *
 * 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/rcupdate.h>
#include <linux/timer.h>
#include <linux/workqueue.h>
#include <asm/unaligned.h>

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

struct workqueue_struct *rport_event_queue;

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_recv_plogi_req(struct fc_lport *,
                                    struct fc_seq *, struct fc_frame *);
static void fc_rport_recv_prli_req(struct fc_rport_priv *,
                                   struct fc_seq *, struct fc_frame *);
static void fc_rport_recv_prlo_req(struct fc_rport_priv *,
                                   struct fc_seq *, struct fc_frame *);
static void fc_rport_recv_logo_req(struct fc_lport *,
                                   struct fc_seq *, 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_PLOGI] = "PLOGI",
        [RPORT_ST_PRLI] = "PRLI",
        [RPORT_ST_RTV] = "RTV",
        [RPORT_ST_READY] = "Ready",
        [RPORT_ST_LOGO] = "LOGO",
        [RPORT_ST_DELETE] = "Delete",
};

/**
 * fc_rport_lookup() - lookup a remote port by port_id
 * @lport: Fibre Channel host port instance
 * @port_id: remote port port_id to match
 */
static struct fc_rport_priv *fc_rport_lookup(const struct fc_lport *lport,
                                             u32 port_id)
{
        struct fc_rport_priv *rdata;

        list_for_each_entry(rdata, &lport->disc.rports, peers)
                if (rdata->ids.port_id == port_id &&
                    rdata->rp_state != RPORT_ST_DELETE)
                        return rdata;
        return NULL;
}

/**
 * fc_rport_create() - Create a new remote port
 * @lport:   The local port that the new remote port is for
 * @port_id: The port ID for the new remote port
 *
 * Locking note:  must be called with the disc_mutex held.
 */
static struct fc_rport_priv *fc_rport_create(struct fc_lport *lport,
                                             u32 port_id)
{
        struct fc_rport_priv *rdata;

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

        rdata = kzalloc(sizeof(*rdata), 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)
                list_add(&rdata->peers, &lport->disc.rports);
        return rdata;
}

/**
 * fc_rport_destroy() - free a remote port after last reference is released.
 * @kref: pointer to kref inside struct fc_rport_priv
 */
static void fc_rport_destroy(struct kref *kref)
{
        struct fc_rport_priv *rdata;

        rdata = container_of(kref, struct fc_rport_priv, kref);
        kfree(rdata);
}

/**
 * fc_rport_state() - return a string for the state the rport is in
 * @rdata: remote port private data
 */
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 in seconds.
 * @rport: Pointer to Fibre Channel remote port structure
 * @timeout: timeout in seconds
 */
void fc_set_rport_loss_tmo(struct fc_rport *rport, u32 timeout)
{
        if (timeout)
                rport->dev_loss_tmo = timeout + 5;
        else
                rport->dev_loss_tmo = 30;
}
EXPORT_SYMBOL(fc_set_rport_loss_tmo);

/**
 * fc_plogi_get_maxframe() - Get max payload from the common service parameters
 * @flp: FLOGI payload structure
 * @maxval: upper limit, 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 rport's state
 * @rdata: The rport whose state should change
 * @new: The new state of the rport
 *
 * Locking Note: Called with the rport lock held
 */
static void fc_rport_state_enter(struct fc_rport_priv *rdata,
                                 enum fc_rport_state new)
{
        if (rdata->rp_state != new)
                rdata->retries = 0;
        rdata->rp_state = new;
}

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 *rp;
        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;

        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;
                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;

                rp = rport->dd_data;
                rp->local_port = lport;
                rp->rp_state = rdata->rp_state;
                rp->flags = rdata->flags;
                rp->e_d_tov = rdata->e_d_tov;
                rp->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);
                }
                kref_put(&rdata->kref, lport->tt.rport_destroy);
                break;

        case RPORT_EV_FAILED:
        case RPORT_EV_LOGO:
        case RPORT_EV_STOP:
                port_id = rdata->ids.port_id;
                mutex_unlock(&rdata->rp_mutex);

                if (port_id != FC_FID_DIR_SERV) {
                        mutex_lock(&lport->disc.disc_mutex);
                        list_del(&rdata->peers);
                        mutex_unlock(&lport->disc.disc_mutex);
                }

                if (rport_ops && rport_ops->event_callback) {
                        FC_RPORT_DBG(rdata, "callback ev %d\n", event);
                        rport_ops->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) {
                        rp = rport->dd_data;
                        rp->rp_state = RPORT_ST_DELETE;
                        mutex_lock(&rdata->rp_mutex);
                        rdata->rport = NULL;
                        mutex_unlock(&rdata->rp_mutex);
                        fc_remote_port_delete(rport);
                }
                kref_put(&rdata->kref, lport->tt.rport_destroy);
                break;

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

/**
 * fc_rport_login() - Start the remote port login state machine
 * @rdata: private remote port
 *
 * Locking Note: Called without the rport lock held. This
 * function will hold the rport lock, call an _enter_*
 * function and then unlock the rport.
 */
int fc_rport_login(struct fc_rport_priv *rdata)
{
        mutex_lock(&rdata->rp_mutex);

        FC_RPORT_DBG(rdata, "Login to port\n");

        fc_rport_enter_plogi(rdata);

        mutex_unlock(&rdata->rp_mutex);

        return 0;
}

/**
 * fc_rport_enter_delete() - schedule a remote port to be deleted.
 * @rdata: private remote port
 * @event: event to report as the reason for deletion
 *
 * Locking Note: Called with the rport lock held.
 *
 * 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)
{
        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 an rport
 * @rdata: private remote port
 *
 * Locking Note: Called without the rport lock held. This
 * function will hold the rport lock, call an _enter_*
 * function and then unlock the rport.
 */
int fc_rport_logoff(struct fc_rport_priv *rdata)
{
        mutex_lock(&rdata->rp_mutex);

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

        if (rdata->rp_state == RPORT_ST_DELETE) {
                FC_RPORT_DBG(rdata, "Port in Delete state, not removing\n");
                mutex_unlock(&rdata->rp_mutex);
                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);
        mutex_unlock(&rdata->rp_mutex);

out:
        return 0;
}

/**
 * fc_rport_enter_ready() - The rport is ready
 * @rdata: private remote port
 *
 * Locking Note: The rport lock is expected to be held before calling
 * this routine.
 */
static void fc_rport_enter_ready(struct fc_rport_priv *rdata)
{
        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: The work struct of the fc_rport_priv
 *
 * 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_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_LOGO:
                fc_rport_enter_logo(rdata);
                break;
        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: private remote port
 * @fp: The frame pointer
 *
 * Locking Note: The rport lock is expected to be held before
 * calling this routine
 */
static void fc_rport_error(struct fc_rport_priv *rdata, struct fc_frame *fp)
{
        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_PLOGI:
        case RPORT_ST_PRLI:
        case RPORT_ST_LOGO:
                fc_rport_enter_delete(rdata, RPORT_EV_FAILED);
                break;
        case RPORT_ST_RTV:
                fc_rport_enter_ready(rdata);
                break;
        case RPORT_ST_DELETE:
        case RPORT_ST_READY:
        case RPORT_ST_INIT:
                break;
        }
}

/**
 * fc_rport_error_retry() - Error handler when retries are desired
 * @rdata: private remote port data
 * @fp: The frame pointer
 *
 * If the error was an exchange timeout retry immediately,
 * otherwise wait for E_D_TOV.
 *
 * Locking Note: The rport lock is expected to be held before
 * calling this routine
 */
static void fc_rport_error_retry(struct fc_rport_priv *rdata,
                                 struct fc_frame *fp)
{
        unsigned long delay = FC_DEF_E_D_TOV;

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

        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;
        }

        return fc_rport_error(rdata, fp);
}

/**
 * fc_rport_plogi_recv_resp() - Handle incoming ELS PLOGI response
 * @sp: current sequence in the PLOGI exchange
 * @fp: response frame
 * @rdata_arg: private remote port data
 *
 * 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;
        unsigned int tov;
        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);

                tov = ntohl(plp->fl_csp.sp_e_d_tov);
                if (ntohs(plp->fl_csp.sp_features) & FC_SP_FT_EDTR)
                        tov /= 1000;
                if (tov > rdata->e_d_tov)
                        rdata->e_d_tov = tov;
                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, rdata->local_port->tt.rport_destroy);
}

/**
 * fc_rport_enter_plogi() - Send Port Login (PLOGI) request to peer
 * @rdata: private remote port data
 *
 * Locking Note: The rport lock is expected to be held before calling
 * this routine.
 */
static void fc_rport_enter_plogi(struct fc_rport_priv *rdata)
{
        struct fc_lport *lport = rdata->local_port;
        struct fc_frame *fp;

        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_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, lport->e_d_tov))
                fc_rport_error_retry(rdata, fp);
        else
                kref_get(&rdata->kref);
}

/**
 * fc_rport_prli_resp() - Process Login (PRLI) response handler
 * @sp: current sequence in the PRLI exchange
 * @fp: response frame
 * @rdata_arg: private remote port data
 *
 * 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;
        u32 roles = FC_RPORT_ROLE_UNKNOWN;
        u32 fcp_parm = 0;
        u8 op;

        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 && pp->prli.prli_spp_len >= sizeof(pp->spp)) {
                        fcp_parm = ntohl(pp->spp.spp_params);
                        if (fcp_parm & FCP_SPPF_RETRY)
                                rdata->flags |= FC_RP_FLAGS_RETRY;
                }

                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_enter_delete(rdata, RPORT_EV_FAILED);
        }

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

/**
 * fc_rport_logo_resp() - Logout (LOGO) response handler
 * @sp: current sequence in the LOGO exchange
 * @fp: response frame
 * @rdata_arg: private remote port data
 *
 * 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_logo_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 LOGO %s\n", fc_els_resp_type(fp));

        if (rdata->rp_state != RPORT_ST_LOGO) {
                FC_RPORT_DBG(rdata, "Received a LOGO 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) {
                fc_rport_enter_rtv(rdata);
        } else {
                FC_RPORT_DBG(rdata, "Bad ELS response for LOGO command\n");
                fc_rport_enter_delete(rdata, RPORT_EV_LOGO);
        }

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 to peer
 * @rdata: private remote port data
 *
 * Locking Note: The rport lock is expected to be held before calling
 * this routine.
 */
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;

        /*
         * 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;
        }

        if (!lport->tt.elsct_send(lport, rdata->ids.port_id, fp, ELS_PRLI,
                                  fc_rport_prli_resp, rdata, lport->e_d_tov))
                fc_rport_error_retry(rdata, fp);
        else
                kref_get(&rdata->kref);
}

/**
 * fc_rport_els_rtv_resp() - Request Timeout Value response handler
 * @sp: current sequence in the RTV exchange
 * @fp: response frame
 * @rdata_arg: private remote port data
 *
 * 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 to peer
 * @rdata: private remote port data
 *
 * Locking Note: The rport lock is expected to be held before calling
 * this routine.
 */
static void fc_rport_enter_rtv(struct fc_rport_priv *rdata)
{
        struct fc_frame *fp;
        struct fc_lport *lport = rdata->local_port;

        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, lport->e_d_tov))
                fc_rport_error_retry(rdata, fp);
        else
                kref_get(&rdata->kref);
}

/**
 * fc_rport_enter_logo() - Send Logout (LOGO) request to peer
 * @rdata: private remote port data
 *
 * Locking Note: The rport lock is expected to be held before calling
 * this routine.
 */
static void fc_rport_enter_logo(struct fc_rport_priv *rdata)
{
        struct fc_lport *lport = rdata->local_port;
        struct fc_frame *fp;

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

        fc_rport_state_enter(rdata, RPORT_ST_LOGO);

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

        if (!lport->tt.elsct_send(lport, rdata->ids.port_id, fp, ELS_LOGO,
                                  fc_rport_logo_resp, rdata, lport->e_d_tov))
                fc_rport_error_retry(rdata, fp);
        else
                kref_get(&rdata->kref);
}

/**
 * fc_rport_recv_els_req() - handle a validated ELS request.
 * @lport: Fibre Channel local port
 * @sp: current sequence in the PLOGI exchange
 * @fp: response frame
 *
 * Handle incoming ELS requests that require port login.
 * The ELS opcode has already been validated by the caller.
 *
 * Locking Note: Called with the lport lock held.
 */
static void fc_rport_recv_els_req(struct fc_lport *lport,
                                  struct fc_seq *sp, struct fc_frame *fp)
{
        struct fc_rport_priv *rdata;
        struct fc_frame_header *fh;
        struct fc_seq_els_data els_data;

        els_data.fp = NULL;
        els_data.reason = ELS_RJT_UNAB;
        els_data.explan = ELS_EXPL_PLOGI_REQD;

        fh = fc_frame_header_get(fp);

        mutex_lock(&lport->disc.disc_mutex);
        rdata = lport->tt.rport_lookup(lport, ntoh24(fh->fh_s_id));
        if (!rdata) {
                mutex_unlock(&lport->disc.disc_mutex);
                goto reject;
        }
        mutex_lock(&rdata->rp_mutex);
        mutex_unlock(&lport->disc.disc_mutex);

        switch (rdata->rp_state) {
        case RPORT_ST_PRLI:
        case RPORT_ST_RTV:
        case RPORT_ST_READY:
                break;
        default:
                mutex_unlock(&rdata->rp_mutex);
                goto reject;
        }

        switch (fc_frame_payload_op(fp)) {
        case ELS_PRLI:
                fc_rport_recv_prli_req(rdata, sp, fp);
                break;
        case ELS_PRLO:
                fc_rport_recv_prlo_req(rdata, sp, fp);
                break;
        case ELS_RRQ:
                els_data.fp = fp;
                lport->tt.seq_els_rsp_send(sp, ELS_RRQ, &els_data);
                break;
        case ELS_REC:
                els_data.fp = fp;
                lport->tt.seq_els_rsp_send(sp, ELS_REC, &els_data);
                break;
        default:
                fc_frame_free(fp);      /* can't happen */
                break;
        }

        mutex_unlock(&rdata->rp_mutex);
        return;

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

/**
 * fc_rport_recv_req() - Handle a received ELS request from a rport
 * @sp: current sequence in the PLOGI exchange
 * @fp: response frame
 * @lport: Fibre Channel local port
 *
 * Locking Note: Called with the lport lock held.
 */
void fc_rport_recv_req(struct fc_seq *sp, struct fc_frame *fp,
                       struct fc_lport *lport)
{
        struct fc_seq_els_data els_data;

        /*
         * Handle 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_PLOGI:
                fc_rport_recv_plogi_req(lport, sp, fp);
                break;
        case ELS_LOGO:
                fc_rport_recv_logo_req(lport, sp, fp);
                break;
        case ELS_PRLI:
        case ELS_PRLO:
        case ELS_RRQ:
        case ELS_REC:
                fc_rport_recv_els_req(lport, sp, fp);
                break;
        default:
                fc_frame_free(fp);
                els_data.fp = NULL;
                els_data.reason = ELS_RJT_UNSUP;
                els_data.explan = ELS_EXPL_NONE;
                lport->tt.seq_els_rsp_send(sp, ELS_LS_RJT, &els_data);
                break;
        }
}

/**
 * fc_rport_recv_plogi_req() - Handle incoming Port Login (PLOGI) request
 * @lport: local port
 * @sp: current sequence in the PLOGI exchange
 * @fp: PLOGI request frame
 *
 * Locking Note: The rport lock is held before calling this function.
 */
static void fc_rport_recv_plogi_req(struct fc_lport *lport,
                                    struct fc_seq *sp, struct fc_frame *rx_fp)
{
        struct fc_disc *disc;
        struct fc_rport_priv *rdata;
        struct fc_frame *fp = rx_fp;
        struct fc_exch *ep;
        struct fc_frame_header *fh;
        struct fc_els_flogi *pl;
        struct fc_seq_els_data rjt_data;
        u32 sid, f_ctl;

        rjt_data.fp = NULL;
        fh = fc_frame_header_get(fp);
        sid = ntoh24(fh->fh_s_id);

        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:
                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_READY:
                break;
        case RPORT_ST_DELETE:
        default:
                FC_RPORT_DBG(rdata, "Received PLOGI in unexpected state %d\n",
                             rdata->rp_state);
                fc_frame_free(rx_fp);
                goto out;
        }

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

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

        fc_plogi_fill(lport, fp, ELS_LS_ACC);
        f_ctl = FC_FC_EX_CTX | FC_FC_LAST_SEQ | FC_FC_END_SEQ | FC_FC_SEQ_INIT;
        ep = fc_seq_exch(sp);
        fc_fill_fc_hdr(fp, FC_RCTL_ELS_REP, ep->did, ep->sid,
                       FC_TYPE_ELS, f_ctl, 0);
        lport->tt.seq_send(lport, sp, fp);
        fc_rport_enter_prli(rdata);
out:
        mutex_unlock(&rdata->rp_mutex);
        return;

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

/**
 * fc_rport_recv_prli_req() - Handle incoming Process Login (PRLI) request
 * @rdata: private remote port data
 * @sp: current sequence in the PRLI exchange
 * @fp: PRLI request frame
 *
 * Locking Note: The rport lock is exected to be held before calling
 * this function.
 */
static void fc_rport_recv_prli_req(struct fc_rport_priv *rdata,
                                   struct fc_seq *sp, struct fc_frame *rx_fp)
{
        struct fc_lport *lport = rdata->local_port;
        struct fc_exch *ep;
        struct fc_frame *fp;
        struct fc_frame_header *fh;
        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_rjt_reason reason = ELS_RJT_UNAB;
        enum fc_els_rjt_explan explan = ELS_EXPL_NONE;
        enum fc_els_spp_resp resp;
        struct fc_seq_els_data rjt_data;
        u32 f_ctl;
        u32 fcp_parm;
        u32 roles = FC_RPORT_ROLE_UNKNOWN;
        rjt_data.fp = NULL;

        fh = fc_frame_header_get(rx_fp);

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

        switch (rdata->rp_state) {
        case RPORT_ST_PRLI:
        case RPORT_ST_RTV:
        case RPORT_ST_READY:
                reason = ELS_RJT_NONE;
                break;
        default:
                fc_frame_free(rx_fp);
                return;
                break;
        }
        len = fr_len(rx_fp) - sizeof(*fh);
        pp = fc_frame_payload_get(rx_fp, sizeof(*pp));
        if (pp == NULL) {
                reason = ELS_RJT_PROT;
                explan = ELS_EXPL_INV_LEN;
        } else {
                plen = ntohs(pp->prli.prli_len);
                if ((plen % 4) != 0 || plen > len) {
                        reason = ELS_RJT_PROT;
                        explan = ELS_EXPL_INV_LEN;
                } else if (plen < len) {
                        len = plen;
                }
                plen = pp->prli.prli_spp_len;
                if ((plen % 4) != 0 || plen < sizeof(*spp) ||
                    plen > len || len < sizeof(*pp)) {
                        reason = ELS_RJT_PROT;
                        explan = ELS_EXPL_INV_LEN;
                }
                rspp = &pp->spp;
        }
        if (reason != ELS_RJT_NONE ||
            (fp = fc_frame_alloc(lport, len)) == NULL) {
                rjt_data.reason = reason;
                rjt_data.explan = explan;
                lport->tt.seq_els_rsp_send(sp, ELS_LS_RJT, &rjt_data);
        } else {
                sp = lport->tt.seq_start_next(sp);
                WARN_ON(!sp);
                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);

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

                /*
                 * 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;
                while (len >= plen) {
                        spp->spp_type = rspp->spp_type;
                        spp->spp_type_ext = rspp->spp_type_ext;
                        spp->spp_flags = rspp->spp_flags & FC_SPP_EST_IMG_PAIR;
                        resp = FC_SPP_RESP_ACK;
                        if (rspp->spp_flags & FC_SPP_RPA_VAL)
                                resp = FC_SPP_RESP_NO_PA;
                        switch (rspp->spp_type) {
                        case 0: /* common to all FC-4 types */
                                break;
                        case FC_TYPE_FCP:
                                fcp_parm = ntohl(rspp->spp_params);
                                if (fcp_parm * FCP_SPPF_RETRY)
                                        rdata->flags |= FC_RP_FLAGS_RETRY;
                                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;

                                spp->spp_params =
                                        htonl(lport->service_params);
                                break;
                        default:
                                resp = FC_SPP_RESP_INVL;
                                break;
                        }
                        spp->spp_flags |= resp;
                        len -= plen;
                        rspp = (struct fc_els_spp *)((char *)rspp + plen);
                        spp = (struct fc_els_spp *)((char *)spp + plen);
                }

                /*
                 * Send LS_ACC.  If this fails, the originator should retry.
                 */
                f_ctl = FC_FC_EX_CTX | FC_FC_LAST_SEQ;
                f_ctl |= FC_FC_END_SEQ | FC_FC_SEQ_INIT;
                ep = fc_seq_exch(sp);
                fc_fill_fc_hdr(fp, FC_RCTL_ELS_REP, ep->did, ep->sid,
                               FC_TYPE_ELS, f_ctl, 0);
                lport->tt.seq_send(lport, sp, fp);

                /*
                 * Get lock and re-check state.
                 */
                switch (rdata->rp_state) {
                case RPORT_ST_PRLI:
                        fc_rport_enter_ready(rdata);
                        break;
                case RPORT_ST_READY:
                        break;
                default:
                        break;
                }
        }
        fc_frame_free(rx_fp);
}

/**
 * fc_rport_recv_prlo_req() - Handle incoming Process Logout (PRLO) request
 * @rdata: private remote port data
 * @sp: current sequence in the PRLO exchange
 * @fp: PRLO request frame
 *
 * Locking Note: The rport lock is exected to be held before calling
 * this function.
 */
static void fc_rport_recv_prlo_req(struct fc_rport_priv *rdata,
                                   struct fc_seq *sp,
                                   struct fc_frame *fp)
{
        struct fc_lport *lport = rdata->local_port;

        struct fc_frame_header *fh;
        struct fc_seq_els_data rjt_data;

        fh = fc_frame_header_get(fp);

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

        rjt_data.fp = NULL;
        rjt_data.reason = ELS_RJT_UNAB;
        rjt_data.explan = ELS_EXPL_NONE;
        lport->tt.seq_els_rsp_send(sp, ELS_LS_RJT, &rjt_data);
        fc_frame_free(fp);
}

/**
 * fc_rport_recv_logo_req() - Handle incoming Logout (LOGO) request
 * @lport: local port.
 * @sp: current sequence in the LOGO exchange
 * @fp: LOGO request frame
 *
 * Locking Note: The rport lock is exected to be held before calling
 * this function.
 */
static void fc_rport_recv_logo_req(struct fc_lport *lport,
                                   struct fc_seq *sp,
                                   struct fc_frame *fp)
{
        struct fc_frame_header *fh;
        struct fc_rport_priv *rdata;
        u32 sid;

        fh = fc_frame_header_get(fp);
        sid = ntoh24(fh->fh_s_id);

        mutex_lock(&lport->disc.disc_mutex);
        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);
        } else
                FC_RPORT_ID_DBG(lport, sid,
                                "Received LOGO from non-logged-in port\n");
        mutex_unlock(&lport->disc.disc_mutex);
        lport->tt.seq_els_rsp_send(sp, ELS_LS_ACC, NULL);
        fc_frame_free(fp);
}

static void fc_rport_flush_queue(void)
{
        flush_workqueue(rport_event_queue);
}

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);

int fc_setup_rport(void)
{
        rport_event_queue = create_singlethread_workqueue("fc_rport_eq");
        if (!rport_event_queue)
                return -ENOMEM;
        return 0;
}
EXPORT_SYMBOL(fc_setup_rport);

void fc_destroy_rport(void)
{
        destroy_workqueue(rport_event_queue);
}
EXPORT_SYMBOL(fc_destroy_rport);

void fc_rport_terminate_io(struct fc_rport *rport)
{
        struct fc_rport_libfc_priv *rp = rport->dd_data;
        struct fc_lport *lport = rp->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);