Add the rt linux 4.1.3-rt3 as base
[kvmfornfv.git] / kernel / drivers / scsi / libfc / fc_disc.c
diff --git a/kernel/drivers/scsi/libfc/fc_disc.c b/kernel/drivers/scsi/libfc/fc_disc.c
new file mode 100644 (file)
index 0000000..880a906
--- /dev/null
@@ -0,0 +1,753 @@
+/*
+ * 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
+ */
+
+/*
+ * Target Discovery
+ *
+ * This block discovers all FC-4 remote ports, including FCP initiators. It
+ * also handles RSCN events and re-discovery if necessary.
+ */
+
+/*
+ * DISC LOCKING
+ *
+ * The disc mutex is can be locked when acquiring rport locks, but may not
+ * be held when acquiring the lport lock. Refer to fc_lport.c for more
+ * details.
+ */
+
+#include <linux/timer.h>
+#include <linux/slab.h>
+#include <linux/err.h>
+#include <linux/export.h>
+#include <asm/unaligned.h>
+
+#include <scsi/fc/fc_gs.h>
+
+#include <scsi/libfc.h>
+
+#include "fc_libfc.h"
+
+#define FC_DISC_RETRY_LIMIT    3       /* max retries */
+#define FC_DISC_RETRY_DELAY    500UL   /* (msecs) delay */
+
+static void fc_disc_gpn_ft_req(struct fc_disc *);
+static void fc_disc_gpn_ft_resp(struct fc_seq *, struct fc_frame *, void *);
+static void fc_disc_done(struct fc_disc *, enum fc_disc_event);
+static void fc_disc_timeout(struct work_struct *);
+static int fc_disc_single(struct fc_lport *, struct fc_disc_port *);
+static void fc_disc_restart(struct fc_disc *);
+
+/**
+ * fc_disc_stop_rports() - Delete all the remote ports associated with the lport
+ * @disc: The discovery job to stop remote ports on
+ *
+ * Locking Note: This function expects that the lport mutex is locked before
+ * calling it.
+ */
+static void fc_disc_stop_rports(struct fc_disc *disc)
+{
+       struct fc_lport *lport;
+       struct fc_rport_priv *rdata;
+
+       lport = fc_disc_lport(disc);
+
+       mutex_lock(&disc->disc_mutex);
+       list_for_each_entry_rcu(rdata, &disc->rports, peers)
+               lport->tt.rport_logoff(rdata);
+       mutex_unlock(&disc->disc_mutex);
+}
+
+/**
+ * fc_disc_recv_rscn_req() - Handle Registered State Change Notification (RSCN)
+ * @disc:  The discovery object to which the RSCN applies
+ * @fp:           The RSCN frame
+ *
+ * Locking Note: This function expects that the disc_mutex is locked
+ *              before it is called.
+ */
+static void fc_disc_recv_rscn_req(struct fc_disc *disc, struct fc_frame *fp)
+{
+       struct fc_lport *lport;
+       struct fc_els_rscn *rp;
+       struct fc_els_rscn_page *pp;
+       struct fc_seq_els_data rjt_data;
+       unsigned int len;
+       int redisc = 0;
+       enum fc_els_rscn_ev_qual ev_qual;
+       enum fc_els_rscn_addr_fmt fmt;
+       LIST_HEAD(disc_ports);
+       struct fc_disc_port *dp, *next;
+
+       lport = fc_disc_lport(disc);
+
+       FC_DISC_DBG(disc, "Received an RSCN event\n");
+
+       /* make sure the frame contains an RSCN message */
+       rp = fc_frame_payload_get(fp, sizeof(*rp));
+       if (!rp)
+               goto reject;
+       /* make sure the page length is as expected (4 bytes) */
+       if (rp->rscn_page_len != sizeof(*pp))
+               goto reject;
+       /* get the RSCN payload length */
+       len = ntohs(rp->rscn_plen);
+       if (len < sizeof(*rp))
+               goto reject;
+       /* make sure the frame contains the expected payload */
+       rp = fc_frame_payload_get(fp, len);
+       if (!rp)
+               goto reject;
+       /* payload must be a multiple of the RSCN page size */
+       len -= sizeof(*rp);
+       if (len % sizeof(*pp))
+               goto reject;
+
+       for (pp = (void *)(rp + 1); len > 0; len -= sizeof(*pp), pp++) {
+               ev_qual = pp->rscn_page_flags >> ELS_RSCN_EV_QUAL_BIT;
+               ev_qual &= ELS_RSCN_EV_QUAL_MASK;
+               fmt = pp->rscn_page_flags >> ELS_RSCN_ADDR_FMT_BIT;
+               fmt &= ELS_RSCN_ADDR_FMT_MASK;
+               /*
+                * if we get an address format other than port
+                * (area, domain, fabric), then do a full discovery
+                */
+               switch (fmt) {
+               case ELS_ADDR_FMT_PORT:
+                       FC_DISC_DBG(disc, "Port address format for port "
+                                   "(%6.6x)\n", ntoh24(pp->rscn_fid));
+                       dp = kzalloc(sizeof(*dp), GFP_KERNEL);
+                       if (!dp) {
+                               redisc = 1;
+                               break;
+                       }
+                       dp->lp = lport;
+                       dp->port_id = ntoh24(pp->rscn_fid);
+                       list_add_tail(&dp->peers, &disc_ports);
+                       break;
+               case ELS_ADDR_FMT_AREA:
+               case ELS_ADDR_FMT_DOM:
+               case ELS_ADDR_FMT_FAB:
+               default:
+                       FC_DISC_DBG(disc, "Address format is (%d)\n", fmt);
+                       redisc = 1;
+                       break;
+               }
+       }
+       lport->tt.seq_els_rsp_send(fp, ELS_LS_ACC, NULL);
+
+       /*
+        * If not doing a complete rediscovery, do GPN_ID on
+        * the individual ports mentioned in the list.
+        * If any of these get an error, do a full rediscovery.
+        * In any case, go through the list and free the entries.
+        */
+       list_for_each_entry_safe(dp, next, &disc_ports, peers) {
+               list_del(&dp->peers);
+               if (!redisc)
+                       redisc = fc_disc_single(lport, dp);
+               kfree(dp);
+       }
+       if (redisc) {
+               FC_DISC_DBG(disc, "RSCN received: rediscovering\n");
+               fc_disc_restart(disc);
+       } else {
+               FC_DISC_DBG(disc, "RSCN received: not rediscovering. "
+                           "redisc %d state %d in_prog %d\n",
+                           redisc, lport->state, disc->pending);
+       }
+       fc_frame_free(fp);
+       return;
+reject:
+       FC_DISC_DBG(disc, "Received a bad RSCN frame\n");
+       rjt_data.reason = ELS_RJT_LOGIC;
+       rjt_data.explan = ELS_EXPL_NONE;
+       lport->tt.seq_els_rsp_send(fp, ELS_LS_RJT, &rjt_data);
+       fc_frame_free(fp);
+}
+
+/**
+ * fc_disc_recv_req() - Handle incoming requests
+ * @lport: The local port receiving the request
+ * @fp:           The request frame
+ *
+ * Locking Note: This function is called from the EM and will lock
+ *              the disc_mutex before calling the handler for the
+ *              request.
+ */
+static void fc_disc_recv_req(struct fc_lport *lport, struct fc_frame *fp)
+{
+       u8 op;
+       struct fc_disc *disc = &lport->disc;
+
+       op = fc_frame_payload_op(fp);
+       switch (op) {
+       case ELS_RSCN:
+               mutex_lock(&disc->disc_mutex);
+               fc_disc_recv_rscn_req(disc, fp);
+               mutex_unlock(&disc->disc_mutex);
+               break;
+       default:
+               FC_DISC_DBG(disc, "Received an unsupported request, "
+                           "the opcode is (%x)\n", op);
+               fc_frame_free(fp);
+               break;
+       }
+}
+
+/**
+ * fc_disc_restart() - Restart discovery
+ * @disc: The discovery object to be restarted
+ *
+ * Locking Note: This function expects that the disc mutex
+ *              is already locked.
+ */
+static void fc_disc_restart(struct fc_disc *disc)
+{
+       if (!disc->disc_callback)
+               return;
+
+       FC_DISC_DBG(disc, "Restarting discovery\n");
+
+       disc->requested = 1;
+       if (disc->pending)
+               return;
+
+       /*
+        * Advance disc_id.  This is an arbitrary non-zero number that will
+        * match the value in the fc_rport_priv after discovery for all
+        * freshly-discovered remote ports.  Avoid wrapping to zero.
+        */
+       disc->disc_id = (disc->disc_id + 2) | 1;
+       disc->retry_count = 0;
+       fc_disc_gpn_ft_req(disc);
+}
+
+/**
+ * fc_disc_start() - Start discovery on a local port
+ * @lport:        The local port to have discovery started on
+ * @disc_callback: Callback function to be called when discovery is complete
+ */
+static void fc_disc_start(void (*disc_callback)(struct fc_lport *,
+                                               enum fc_disc_event),
+                         struct fc_lport *lport)
+{
+       struct fc_disc *disc = &lport->disc;
+
+       /*
+        * At this point we may have a new disc job or an existing
+        * one. Either way, let's lock when we make changes to it
+        * and send the GPN_FT request.
+        */
+       mutex_lock(&disc->disc_mutex);
+       disc->disc_callback = disc_callback;
+       fc_disc_restart(disc);
+       mutex_unlock(&disc->disc_mutex);
+}
+
+/**
+ * fc_disc_done() - Discovery has been completed
+ * @disc:  The discovery context
+ * @event: The discovery completion status
+ *
+ * Locking Note: This function expects that the disc mutex is locked before
+ * it is called. The discovery callback is then made with the lock released,
+ * and the lock is re-taken before returning from this function
+ */
+static void fc_disc_done(struct fc_disc *disc, enum fc_disc_event event)
+{
+       struct fc_lport *lport = fc_disc_lport(disc);
+       struct fc_rport_priv *rdata;
+
+       FC_DISC_DBG(disc, "Discovery complete\n");
+
+       disc->pending = 0;
+       if (disc->requested) {
+               fc_disc_restart(disc);
+               return;
+       }
+
+       /*
+        * Go through all remote ports.  If they were found in the latest
+        * discovery, reverify or log them in.  Otherwise, log them out.
+        * Skip ports which were never discovered.  These are the dNS port
+        * and ports which were created by PLOGI.
+        */
+       list_for_each_entry_rcu(rdata, &disc->rports, peers) {
+               if (!rdata->disc_id)
+                       continue;
+               if (rdata->disc_id == disc->disc_id)
+                       lport->tt.rport_login(rdata);
+               else
+                       lport->tt.rport_logoff(rdata);
+       }
+
+       mutex_unlock(&disc->disc_mutex);
+       disc->disc_callback(lport, event);
+       mutex_lock(&disc->disc_mutex);
+}
+
+/**
+ * fc_disc_error() - Handle error on dNS request
+ * @disc: The discovery context
+ * @fp:          The error code encoded as a frame pointer
+ */
+static void fc_disc_error(struct fc_disc *disc, struct fc_frame *fp)
+{
+       struct fc_lport *lport = fc_disc_lport(disc);
+       unsigned long delay = 0;
+
+       FC_DISC_DBG(disc, "Error %ld, retries %d/%d\n",
+                   PTR_ERR(fp), disc->retry_count,
+                   FC_DISC_RETRY_LIMIT);
+
+       if (!fp || PTR_ERR(fp) == -FC_EX_TIMEOUT) {
+               /*
+                * Memory allocation failure, or the exchange timed out,
+                * retry after delay.
+                */
+               if (disc->retry_count < FC_DISC_RETRY_LIMIT) {
+                       /* go ahead and retry */
+                       if (!fp)
+                               delay = msecs_to_jiffies(FC_DISC_RETRY_DELAY);
+                       else {
+                               delay = msecs_to_jiffies(lport->e_d_tov);
+
+                               /* timeout faster first time */
+                               if (!disc->retry_count)
+                                       delay /= 4;
+                       }
+                       disc->retry_count++;
+                       schedule_delayed_work(&disc->disc_work, delay);
+               } else
+                       fc_disc_done(disc, DISC_EV_FAILED);
+       } else if (PTR_ERR(fp) == -FC_EX_CLOSED) {
+               /*
+                * if discovery fails due to lport reset, clear
+                * pending flag so that subsequent discovery can
+                * continue
+                */
+               disc->pending = 0;
+       }
+}
+
+/**
+ * fc_disc_gpn_ft_req() - Send Get Port Names by FC-4 type (GPN_FT) request
+ * @lport: The discovery context
+ *
+ * Locking Note: This function expects that the disc_mutex is locked
+ *              before it is called.
+ */
+static void fc_disc_gpn_ft_req(struct fc_disc *disc)
+{
+       struct fc_frame *fp;
+       struct fc_lport *lport = fc_disc_lport(disc);
+
+       WARN_ON(!fc_lport_test_ready(lport));
+
+       disc->pending = 1;
+       disc->requested = 0;
+
+       disc->buf_len = 0;
+       disc->seq_count = 0;
+       fp = fc_frame_alloc(lport,
+                           sizeof(struct fc_ct_hdr) +
+                           sizeof(struct fc_ns_gid_ft));
+       if (!fp)
+               goto err;
+
+       if (lport->tt.elsct_send(lport, 0, fp,
+                                FC_NS_GPN_FT,
+                                fc_disc_gpn_ft_resp,
+                                disc, 3 * lport->r_a_tov))
+               return;
+err:
+       fc_disc_error(disc, NULL);
+}
+
+/**
+ * fc_disc_gpn_ft_parse() - Parse the body of the dNS GPN_FT response.
+ * @lport: The local port the GPN_FT was received on
+ * @buf:   The GPN_FT response buffer
+ * @len:   The size of response buffer
+ *
+ * Goes through the list of IDs and names resulting from a request.
+ */
+static int fc_disc_gpn_ft_parse(struct fc_disc *disc, void *buf, size_t len)
+{
+       struct fc_lport *lport;
+       struct fc_gpn_ft_resp *np;
+       char *bp;
+       size_t plen;
+       size_t tlen;
+       int error = 0;
+       struct fc_rport_identifiers ids;
+       struct fc_rport_priv *rdata;
+
+       lport = fc_disc_lport(disc);
+       disc->seq_count++;
+
+       /*
+        * Handle partial name record left over from previous call.
+        */
+       bp = buf;
+       plen = len;
+       np = (struct fc_gpn_ft_resp *)bp;
+       tlen = disc->buf_len;
+       disc->buf_len = 0;
+       if (tlen) {
+               WARN_ON(tlen >= sizeof(*np));
+               plen = sizeof(*np) - tlen;
+               WARN_ON(plen <= 0);
+               WARN_ON(plen >= sizeof(*np));
+               if (plen > len)
+                       plen = len;
+               np = &disc->partial_buf;
+               memcpy((char *)np + tlen, bp, plen);
+
+               /*
+                * Set bp so that the loop below will advance it to the
+                * first valid full name element.
+                */
+               bp -= tlen;
+               len += tlen;
+               plen += tlen;
+               disc->buf_len = (unsigned char) plen;
+               if (plen == sizeof(*np))
+                       disc->buf_len = 0;
+       }
+
+       /*
+        * Handle full name records, including the one filled from above.
+        * Normally, np == bp and plen == len, but from the partial case above,
+        * bp, len describe the overall buffer, and np, plen describe the
+        * partial buffer, which if would usually be full now.
+        * After the first time through the loop, things return to "normal".
+        */
+       while (plen >= sizeof(*np)) {
+               ids.port_id = ntoh24(np->fp_fid);
+               ids.port_name = ntohll(np->fp_wwpn);
+
+               if (ids.port_id != lport->port_id &&
+                   ids.port_name != lport->wwpn) {
+                       rdata = lport->tt.rport_create(lport, ids.port_id);
+                       if (rdata) {
+                               rdata->ids.port_name = ids.port_name;
+                               rdata->disc_id = disc->disc_id;
+                       } else {
+                               printk(KERN_WARNING "libfc: Failed to allocate "
+                                      "memory for the newly discovered port "
+                                      "(%6.6x)\n", ids.port_id);
+                               error = -ENOMEM;
+                       }
+               }
+
+               if (np->fp_flags & FC_NS_FID_LAST) {
+                       fc_disc_done(disc, DISC_EV_SUCCESS);
+                       len = 0;
+                       break;
+               }
+               len -= sizeof(*np);
+               bp += sizeof(*np);
+               np = (struct fc_gpn_ft_resp *)bp;
+               plen = len;
+       }
+
+       /*
+        * Save any partial record at the end of the buffer for next time.
+        */
+       if (error == 0 && len > 0 && len < sizeof(*np)) {
+               if (np != &disc->partial_buf) {
+                       FC_DISC_DBG(disc, "Partial buffer remains "
+                                   "for discovery\n");
+                       memcpy(&disc->partial_buf, np, len);
+               }
+               disc->buf_len = (unsigned char) len;
+       }
+       return error;
+}
+
+/**
+ * fc_disc_timeout() - Handler for discovery timeouts
+ * @work: Structure holding discovery context that needs to retry discovery
+ */
+static void fc_disc_timeout(struct work_struct *work)
+{
+       struct fc_disc *disc = container_of(work,
+                                           struct fc_disc,
+                                           disc_work.work);
+       mutex_lock(&disc->disc_mutex);
+       fc_disc_gpn_ft_req(disc);
+       mutex_unlock(&disc->disc_mutex);
+}
+
+/**
+ * fc_disc_gpn_ft_resp() - Handle a response frame from Get Port Names (GPN_FT)
+ * @sp:            The sequence that the GPN_FT response was received on
+ * @fp:            The GPN_FT response frame
+ * @lp_arg: The discovery context
+ *
+ * Locking Note: This function is called without disc mutex held, and
+ *              should do all its processing with the mutex held
+ */
+static void fc_disc_gpn_ft_resp(struct fc_seq *sp, struct fc_frame *fp,
+                               void *disc_arg)
+{
+       struct fc_disc *disc = disc_arg;
+       struct fc_ct_hdr *cp;
+       struct fc_frame_header *fh;
+       enum fc_disc_event event = DISC_EV_NONE;
+       unsigned int seq_cnt;
+       unsigned int len;
+       int error = 0;
+
+       mutex_lock(&disc->disc_mutex);
+       FC_DISC_DBG(disc, "Received a GPN_FT response\n");
+
+       if (IS_ERR(fp)) {
+               fc_disc_error(disc, fp);
+               mutex_unlock(&disc->disc_mutex);
+               return;
+       }
+
+       WARN_ON(!fc_frame_is_linear(fp));       /* buffer must be contiguous */
+       fh = fc_frame_header_get(fp);
+       len = fr_len(fp) - sizeof(*fh);
+       seq_cnt = ntohs(fh->fh_seq_cnt);
+       if (fr_sof(fp) == FC_SOF_I3 && seq_cnt == 0 && disc->seq_count == 0) {
+               cp = fc_frame_payload_get(fp, sizeof(*cp));
+               if (!cp) {
+                       FC_DISC_DBG(disc, "GPN_FT response too short, len %d\n",
+                                   fr_len(fp));
+                       event = DISC_EV_FAILED;
+               } else if (ntohs(cp->ct_cmd) == FC_FS_ACC) {
+
+                       /* Accepted, parse the response. */
+                       len -= sizeof(*cp);
+                       error = fc_disc_gpn_ft_parse(disc, cp + 1, len);
+               } else if (ntohs(cp->ct_cmd) == FC_FS_RJT) {
+                       FC_DISC_DBG(disc, "GPN_FT rejected reason %x exp %x "
+                                   "(check zoning)\n", cp->ct_reason,
+                                   cp->ct_explan);
+                       event = DISC_EV_FAILED;
+                       if (cp->ct_reason == FC_FS_RJT_UNABL &&
+                           cp->ct_explan == FC_FS_EXP_FTNR)
+                               event = DISC_EV_SUCCESS;
+               } else {
+                       FC_DISC_DBG(disc, "GPN_FT unexpected response code "
+                                   "%x\n", ntohs(cp->ct_cmd));
+                       event = DISC_EV_FAILED;
+               }
+       } else if (fr_sof(fp) == FC_SOF_N3 && seq_cnt == disc->seq_count) {
+               error = fc_disc_gpn_ft_parse(disc, fh + 1, len);
+       } else {
+               FC_DISC_DBG(disc, "GPN_FT unexpected frame - out of sequence? "
+                           "seq_cnt %x expected %x sof %x eof %x\n",
+                           seq_cnt, disc->seq_count, fr_sof(fp), fr_eof(fp));
+               event = DISC_EV_FAILED;
+       }
+       if (error)
+               fc_disc_error(disc, fp);
+       else if (event != DISC_EV_NONE)
+               fc_disc_done(disc, event);
+       fc_frame_free(fp);
+       mutex_unlock(&disc->disc_mutex);
+}
+
+/**
+ * fc_disc_gpn_id_resp() - Handle a response frame from Get Port Names (GPN_ID)
+ * @sp:               The sequence the GPN_ID is on
+ * @fp:               The response frame
+ * @rdata_arg: The remote port that sent the GPN_ID response
+ *
+ * Locking Note: This function is called without disc mutex held.
+ */
+static void fc_disc_gpn_id_resp(struct fc_seq *sp, struct fc_frame *fp,
+                               void *rdata_arg)
+{
+       struct fc_rport_priv *rdata = rdata_arg;
+       struct fc_rport_priv *new_rdata;
+       struct fc_lport *lport;
+       struct fc_disc *disc;
+       struct fc_ct_hdr *cp;
+       struct fc_ns_gid_pn *pn;
+       u64 port_name;
+
+       lport = rdata->local_port;
+       disc = &lport->disc;
+
+       mutex_lock(&disc->disc_mutex);
+       if (PTR_ERR(fp) == -FC_EX_CLOSED)
+               goto out;
+       if (IS_ERR(fp))
+               goto redisc;
+
+       cp = fc_frame_payload_get(fp, sizeof(*cp));
+       if (!cp)
+               goto redisc;
+       if (ntohs(cp->ct_cmd) == FC_FS_ACC) {
+               if (fr_len(fp) < sizeof(struct fc_frame_header) +
+                   sizeof(*cp) + sizeof(*pn))
+                       goto redisc;
+               pn = (struct fc_ns_gid_pn *)(cp + 1);
+               port_name = get_unaligned_be64(&pn->fn_wwpn);
+               if (rdata->ids.port_name == -1)
+                       rdata->ids.port_name = port_name;
+               else if (rdata->ids.port_name != port_name) {
+                       FC_DISC_DBG(disc, "GPN_ID accepted.  WWPN changed. "
+                                   "Port-id %6.6x wwpn %16.16llx\n",
+                                   rdata->ids.port_id, port_name);
+                       lport->tt.rport_logoff(rdata);
+
+                       new_rdata = lport->tt.rport_create(lport,
+                                                          rdata->ids.port_id);
+                       if (new_rdata) {
+                               new_rdata->disc_id = disc->disc_id;
+                               lport->tt.rport_login(new_rdata);
+                       }
+                       goto out;
+               }
+               rdata->disc_id = disc->disc_id;
+               lport->tt.rport_login(rdata);
+       } else if (ntohs(cp->ct_cmd) == FC_FS_RJT) {
+               FC_DISC_DBG(disc, "GPN_ID rejected reason %x exp %x\n",
+                           cp->ct_reason, cp->ct_explan);
+               lport->tt.rport_logoff(rdata);
+       } else {
+               FC_DISC_DBG(disc, "GPN_ID unexpected response code %x\n",
+                           ntohs(cp->ct_cmd));
+redisc:
+               fc_disc_restart(disc);
+       }
+out:
+       mutex_unlock(&disc->disc_mutex);
+       kref_put(&rdata->kref, lport->tt.rport_destroy);
+}
+
+/**
+ * fc_disc_gpn_id_req() - Send Get Port Names by ID (GPN_ID) request
+ * @lport: The local port to initiate discovery on
+ * @rdata: remote port private data
+ *
+ * Locking Note: This function expects that the disc_mutex is locked
+ *              before it is called.
+ * On failure, an error code is returned.
+ */
+static int fc_disc_gpn_id_req(struct fc_lport *lport,
+                             struct fc_rport_priv *rdata)
+{
+       struct fc_frame *fp;
+
+       fp = fc_frame_alloc(lport, sizeof(struct fc_ct_hdr) +
+                           sizeof(struct fc_ns_fid));
+       if (!fp)
+               return -ENOMEM;
+       if (!lport->tt.elsct_send(lport, rdata->ids.port_id, fp, FC_NS_GPN_ID,
+                                 fc_disc_gpn_id_resp, rdata,
+                                 3 * lport->r_a_tov))
+               return -ENOMEM;
+       kref_get(&rdata->kref);
+       return 0;
+}
+
+/**
+ * fc_disc_single() - Discover the directory information for a single target
+ * @lport: The local port the remote port is associated with
+ * @dp:           The port to rediscover
+ *
+ * Locking Note: This function expects that the disc_mutex is locked
+ *              before it is called.
+ */
+static int fc_disc_single(struct fc_lport *lport, struct fc_disc_port *dp)
+{
+       struct fc_rport_priv *rdata;
+
+       rdata = lport->tt.rport_create(lport, dp->port_id);
+       if (!rdata)
+               return -ENOMEM;
+       rdata->disc_id = 0;
+       return fc_disc_gpn_id_req(lport, rdata);
+}
+
+/**
+ * fc_disc_stop() - Stop discovery for a given lport
+ * @lport: The local port that discovery should stop on
+ */
+static void fc_disc_stop(struct fc_lport *lport)
+{
+       struct fc_disc *disc = &lport->disc;
+
+       if (disc->pending)
+               cancel_delayed_work_sync(&disc->disc_work);
+       fc_disc_stop_rports(disc);
+}
+
+/**
+ * fc_disc_stop_final() - Stop discovery for a given lport
+ * @lport: The lport that discovery should stop on
+ *
+ * This function will block until discovery has been
+ * completely stopped and all rports have been deleted.
+ */
+static void fc_disc_stop_final(struct fc_lport *lport)
+{
+       fc_disc_stop(lport);
+       lport->tt.rport_flush_queue();
+}
+
+/**
+ * fc_disc_config() - Configure the discovery layer for a local port
+ * @lport: The local port that needs the discovery layer to be configured
+ * @priv: Private data structre for users of the discovery layer
+ */
+void fc_disc_config(struct fc_lport *lport, void *priv)
+{
+       struct fc_disc *disc = &lport->disc;
+
+       if (!lport->tt.disc_start)
+               lport->tt.disc_start = fc_disc_start;
+
+       if (!lport->tt.disc_stop)
+               lport->tt.disc_stop = fc_disc_stop;
+
+       if (!lport->tt.disc_stop_final)
+               lport->tt.disc_stop_final = fc_disc_stop_final;
+
+       if (!lport->tt.disc_recv_req)
+               lport->tt.disc_recv_req = fc_disc_recv_req;
+
+       disc = &lport->disc;
+
+       disc->priv = priv;
+}
+EXPORT_SYMBOL(fc_disc_config);
+
+/**
+ * fc_disc_init() - Initialize the discovery layer for a local port
+ * @lport: The local port that needs the discovery layer to be initialized
+ */
+void fc_disc_init(struct fc_lport *lport)
+{
+       struct fc_disc *disc = &lport->disc;
+
+       INIT_DELAYED_WORK(&disc->disc_work, fc_disc_timeout);
+       mutex_init(&disc->disc_mutex);
+       INIT_LIST_HEAD(&disc->rports);
+}
+EXPORT_SYMBOL(fc_disc_init);