X-Git-Url: https://gerrit.opnfv.org/gerrit/gitweb?a=blobdiff_plain;f=kernel%2Fdrivers%2Fscsi%2Flibfc%2Ffc_disc.c;fp=kernel%2Fdrivers%2Fscsi%2Flibfc%2Ffc_disc.c;h=880a9068ca1268baf851ea8804f3bdb4216049f6;hb=9ca8dbcc65cfc63d6f5ef3312a33184e1d726e00;hp=0000000000000000000000000000000000000000;hpb=98260f3884f4a202f9ca5eabed40b1354c489b29;p=kvmfornfv.git

diff --git a/kernel/drivers/scsi/libfc/fc_disc.c b/kernel/drivers/scsi/libfc/fc_disc.c
new file mode 100644
index 000000000..880a9068c
--- /dev/null
+++ b/kernel/drivers/scsi/libfc/fc_disc.c
@@ -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);