[SCSI] libfc: A modular Fibre Channel library

libFC is composed of 4 blocks supported by an exchange manager
and a framing library. The upper 4 layers are fc_lport, fc_disc,
fc_rport and fc_fcp. A LLD that uses libfc could choose to
either use libfc's block, or using the transport template
defined in libfc.h, override one or more blocks with its own
implementation.

The EM (Exchange Manager) manages exhcanges/sequences for all
commands- ELS, CT and FCP.

The framing library frames ELS and CT commands.

The fc_lport block manages the library's representation of the
host's FC enabled ports.

The fc_disc block manages discovery of targets as well as
handling changes that occur in the FC fabric (via. RSCN events).

The fc_rport block manages the library's representation of other
entities in the FC fabric. Currently the library uses this block
for targets, its peer when in point-to-point mode and the
directory server, but can be extended for other entities if
needed.

The fc_fcp block interacts with the scsi-ml and handles all
I/O.

Signed-off-by: Robert Love <robert.w.love@intel.com>
[jejb: added include of delay.h to fix ppc64 compile prob spotted by sfr]
Signed-off-by: James Bottomley <James.Bottomley@HansenPartnership.com>

1 files changed, 845 insertions, 0 deletions

diff --git a/drivers/scsi/libfc/fc_disc.c b/drivers/scsi/libfc/fc_disc.c
new file mode 100644
index 000000000000..dd1564c9e04a
--- /dev/null
+++ b/drivers/scsi/libfc/fc_disc.c
@@ -0,0 +1,845 @@
+/*
+ * 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/err.h>
+#include <asm/unaligned.h>
+
+#include <scsi/fc/fc_gs.h>
+
+#include <scsi/libfc.h>
+
+#define FC_DISC_RETRY_LIMIT	3	/* max retries */
+#define FC_DISC_RETRY_DELAY	500UL	/* (msecs) delay */
+
+#define	FC_DISC_DELAY		3
+
+static int fc_disc_debug;
+
+#define FC_DEBUG_DISC(fmt...)			\
+	do {					\
+		if (fc_disc_debug)		\
+			FC_DBG(fmt);		\
+	} while (0)
+
+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 int fc_disc_new_target(struct fc_disc *, struct fc_rport *,
+			      struct fc_rport_identifiers *);
+static void fc_disc_del_target(struct fc_disc *, struct fc_rport *);
+static void fc_disc_done(struct fc_disc *);
+static void fc_disc_timeout(struct work_struct *);
+static void fc_disc_single(struct fc_disc *, struct fc_disc_port *);
+static void fc_disc_restart(struct fc_disc *);
+
+/**
+ * fc_disc_lookup_rport - lookup a remote port by port_id
+ * @lport: Fibre Channel host port instance
+ * @port_id: remote port port_id to match
+ */
+struct fc_rport *fc_disc_lookup_rport(const struct fc_lport *lport,
+				      u32 port_id)
+{
+	const struct fc_disc *disc = &lport->disc;
+	struct fc_rport *rport, *found = NULL;
+	struct fc_rport_libfc_priv *rdata;
+	int disc_found = 0;
+
+	list_for_each_entry(rdata, &disc->rports, peers) {
+		rport = PRIV_TO_RPORT(rdata);
+		if (rport->port_id == port_id) {
+			disc_found = 1;
+			found = rport;
+			break;
+		}
+	}
+
+	if (!disc_found)
+		found = NULL;
+
+	return found;
+}
+
+/**
+ * fc_disc_stop_rports - delete all the remote ports associated with the lport
+ * @disc: The discovery job to stop rports on
+ *
+ * Locking Note: This function expects that the lport mutex is locked before
+ * calling it.
+ */
+void fc_disc_stop_rports(struct fc_disc *disc)
+{
+	struct fc_lport *lport;
+	struct fc_rport *rport;
+	struct fc_rport_libfc_priv *rdata, *next;
+
+	lport = disc->lport;
+
+	mutex_lock(&disc->disc_mutex);
+	list_for_each_entry_safe(rdata, next, &disc->rports, peers) {
+		rport = PRIV_TO_RPORT(rdata);
+		list_del(&rdata->peers);
+		lport->tt.rport_logoff(rport);
+	}
+
+	mutex_unlock(&disc->disc_mutex);
+}
+
+/**
+ * fc_disc_rport_callback - Event handler for rport events
+ * @lport: The lport which is receiving the event
+ * @rport: The rport which the event has occured on
+ * @event: The event that occured
+ *
+ * Locking Note: The rport lock should not be held when calling
+ *		 this function.
+ */
+static void fc_disc_rport_callback(struct fc_lport *lport,
+				   struct fc_rport *rport,
+				   enum fc_rport_event event)
+{
+	struct fc_rport_libfc_priv *rdata = rport->dd_data;
+	struct fc_disc *disc = &lport->disc;
+	int found = 0;
+
+	FC_DEBUG_DISC("Received a %d event for port (%6x)\n", event,
+		      rport->port_id);
+
+	if (event == RPORT_EV_CREATED) {
+		if (disc) {
+			found = 1;
+			mutex_lock(&disc->disc_mutex);
+			list_add_tail(&rdata->peers, &disc->rports);
+			mutex_unlock(&disc->disc_mutex);
+		}
+	}
+
+	if (!found)
+		FC_DEBUG_DISC("The rport (%6x) is not maintained "
+			      "by the discovery layer\n", rport->port_id);
+}
+
+/**
+ * fc_disc_recv_rscn_req - Handle Registered State Change Notification (RSCN)
+ * @sp: Current sequence of the RSCN exchange
+ * @fp: RSCN Frame
+ * @lport: Fibre Channel host port instance
+ *
+ * Locking Note: This function expects that the disc_mutex is locked
+ *		 before it is called.
+ */
+static void fc_disc_recv_rscn_req(struct fc_seq *sp, struct fc_frame *fp,
+				  struct fc_disc *disc)
+{
+	struct fc_lport *lport;
+	struct fc_rport *rport;
+	struct fc_rport_libfc_priv *rdata;
+	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 = disc->lport;
+
+	FC_DEBUG_DISC("Received an RSCN event on port (%6x)\n",
+		      fc_host_port_id(lport->host));
+
+	/* 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_DEBUG_DISC("Port address format for port (%6x)\n",
+				      ntoh24(pp->rscn_fid));
+			dp = kzalloc(sizeof(*dp), GFP_KERNEL);
+			if (!dp) {
+				redisc = 1;
+				break;
+			}
+			dp->lp = lport;
+			dp->ids.port_id = ntoh24(pp->rscn_fid);
+			dp->ids.port_name = -1;
+			dp->ids.node_name = -1;
+			dp->ids.roles = FC_RPORT_ROLE_UNKNOWN;
+			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_DEBUG_DISC("Address format is (%d)\n", fmt);
+			redisc = 1;
+			break;
+		}
+	}
+	lport->tt.seq_els_rsp_send(sp, ELS_LS_ACC, NULL);
+	if (redisc) {
+		FC_DEBUG_DISC("RSCN received: rediscovering\n");
+		fc_disc_restart(disc);
+	} else {
+		FC_DEBUG_DISC("RSCN received: not rediscovering. "
+			      "redisc %d state %d in_prog %d\n",
+			      redisc, lport->state, disc->pending);
+		list_for_each_entry_safe(dp, next, &disc_ports, peers) {
+			list_del(&dp->peers);
+			rport = lport->tt.rport_lookup(lport, dp->ids.port_id);
+			if (rport) {
+				rdata = RPORT_TO_PRIV(rport);
+				list_del(&rdata->peers);
+				lport->tt.rport_logoff(rport);
+			}
+			fc_disc_single(disc, dp);
+		}
+	}
+	fc_frame_free(fp);
+	return;
+reject:
+	FC_DEBUG_DISC("Received a bad RSCN frame\n");
+	rjt_data.fp = NULL;
+	rjt_data.reason = ELS_RJT_LOGIC;
+	rjt_data.explan = ELS_EXPL_NONE;
+	lport->tt.seq_els_rsp_send(sp, ELS_LS_RJT, &rjt_data);
+	fc_frame_free(fp);
+}
+
+/**
+ * fc_disc_recv_req - Handle incoming requests
+ * @sp: Current sequence of the request exchange
+ * @fp: The frame
+ * @lport: The FC local port
+ *
+ * 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_seq *sp, struct fc_frame *fp,
+			     struct fc_lport *lport)
+{
+	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(sp, fp, disc);
+		mutex_unlock(&disc->disc_mutex);
+		break;
+	default:
+		FC_DBG("Received an unsupported request. opcode (%x)\n", op);
+		break;
+	}
+}
+
+/**
+ * fc_disc_restart - Restart discovery
+ * @lport: FC discovery context
+ *
+ * Locking Note: This function expects that the disc mutex
+ *		 is already locked.
+ */
+static void fc_disc_restart(struct fc_disc *disc)
+{
+	struct fc_rport *rport;
+	struct fc_rport_libfc_priv *rdata, *next;
+	struct fc_lport *lport = disc->lport;
+
+	FC_DEBUG_DISC("Restarting discovery for port (%6x)\n",
+		      fc_host_port_id(lport->host));
+
+	list_for_each_entry_safe(rdata, next, &disc->rports, peers) {
+		rport = PRIV_TO_RPORT(rdata);
+		FC_DEBUG_DISC("list_del(%6x)\n", rport->port_id);
+		list_del(&rdata->peers);
+		lport->tt.rport_logoff(rport);
+	}
+
+	disc->requested = 1;
+	if (!disc->pending)
+		fc_disc_gpn_ft_req(disc);
+}
+
+/**
+ * fc_disc_start - Fibre Channel Target discovery
+ * @lport: FC local port
+ *
+ * Returns non-zero if discovery cannot be started.
+ */
+static void fc_disc_start(void (*disc_callback)(struct fc_lport *,
+						enum fc_disc_event),
+			  struct fc_lport *lport)
+{
+	struct fc_rport *rport;
+	struct fc_rport_identifiers ids;
+	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;
+
+	/*
+	 * If not ready, or already running discovery, just set request flag.
+	 */
+	disc->requested = 1;
+
+	if (disc->pending) {
+		mutex_unlock(&disc->disc_mutex);
+		return;
+	}
+
+	/*
+	 * Handle point-to-point mode as a simple discovery
+	 * of the remote port. Yucky, yucky, yuck, yuck!
+	 */
+	rport = disc->lport->ptp_rp;
+	if (rport) {
+		ids.port_id = rport->port_id;
+		ids.port_name = rport->port_name;
+		ids.node_name = rport->node_name;
+		ids.roles = FC_RPORT_ROLE_UNKNOWN;
+		get_device(&rport->dev);
+
+		if (!fc_disc_new_target(disc, rport, &ids)) {
+			disc->event = DISC_EV_SUCCESS;
+			fc_disc_done(disc);
+		}
+		put_device(&rport->dev);
+	} else {
+		fc_disc_gpn_ft_req(disc);	/* get ports by FC-4 type */
+	}
+
+	mutex_unlock(&disc->disc_mutex);
+}
+
+static struct fc_rport_operations fc_disc_rport_ops = {
+	.event_callback = fc_disc_rport_callback,
+};
+
+/**
+ * fc_disc_new_target - Handle new target found by discovery
+ * @lport: FC local port
+ * @rport: The previous FC remote port (NULL if new remote port)
+ * @ids: Identifiers for the new FC remote port
+ *
+ * Locking Note: This function expects that the disc_mutex is locked
+ *		 before it is called.
+ */
+static int fc_disc_new_target(struct fc_disc *disc,
+			      struct fc_rport *rport,
+			      struct fc_rport_identifiers *ids)
+{
+	struct fc_lport *lport = disc->lport;
+	struct fc_rport_libfc_priv *rp;
+	int error = 0;
+
+	if (rport && ids->port_name) {
+		if (rport->port_name == -1) {
+			/*
+			 * Set WWN and fall through to notify of create.
+			 */
+			fc_rport_set_name(rport, ids->port_name,
+					  rport->node_name);
+		} else if (rport->port_name != ids->port_name) {
+			/*
+			 * This is a new port with the same FCID as
+			 * a previously-discovered port.  Presumably the old
+			 * port logged out and a new port logged in and was
+			 * assigned the same FCID.  This should be rare.
+			 * Delete the old one and fall thru to re-create.
+			 */
+			fc_disc_del_target(disc, rport);
+			rport = NULL;
+		}
+	}
+	if (((ids->port_name != -1) || (ids->port_id != -1)) &&
+	    ids->port_id != fc_host_port_id(lport->host) &&
+	    ids->port_name != lport->wwpn) {
+		if (!rport) {
+			rport = lport->tt.rport_lookup(lport, ids->port_id);
+			if (!rport) {
+				struct fc_disc_port dp;
+				dp.lp = lport;
+				dp.ids.port_id = ids->port_id;
+				dp.ids.port_name = ids->port_name;
+				dp.ids.node_name = ids->node_name;
+				dp.ids.roles = ids->roles;
+				rport = fc_rport_rogue_create(&dp);
+			}
+			if (!rport)
+				error = -ENOMEM;
+		}
+		if (rport) {
+			rp = rport->dd_data;
+			rp->ops = &fc_disc_rport_ops;
+			rp->rp_state = RPORT_ST_INIT;
+			lport->tt.rport_login(rport);
+		}
+	}
+	return error;
+}
+
+/**
+ * fc_disc_del_target - Delete a target
+ * @disc: FC discovery context
+ * @rport: The remote port to be removed
+ */
+static void fc_disc_del_target(struct fc_disc *disc, struct fc_rport *rport)
+{
+	struct fc_lport *lport = disc->lport;
+	struct fc_rport_libfc_priv *rdata = RPORT_TO_PRIV(rport);
+	list_del(&rdata->peers);
+	lport->tt.rport_logoff(rport);
+}
+
+/**
+ * fc_disc_done - Discovery has been completed
+ * @disc: FC discovery context
+ */
+static void fc_disc_done(struct fc_disc *disc)
+{
+	struct fc_lport *lport = disc->lport;
+
+	FC_DEBUG_DISC("Discovery complete for port (%6x)\n",
+		      fc_host_port_id(lport->host));
+
+	disc->disc_callback(lport, disc->event);
+	disc->event = DISC_EV_NONE;
+
+	if (disc->requested)
+		fc_disc_gpn_ft_req(disc);
+	else
+		disc->pending = 0;
+}
+
+/**
+ * fc_disc_error - Handle error on dNS request
+ * @disc: FC discovery context
+ * @fp: The frame pointer
+ */
+static void fc_disc_error(struct fc_disc *disc, struct fc_frame *fp)
+{
+	struct fc_lport *lport = disc->lport;
+	unsigned long delay = 0;
+	if (fc_disc_debug)
+		FC_DBG("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 {
+			/* exceeded retries */
+			disc->event = DISC_EV_FAILED;
+			fc_disc_done(disc);
+		}
+	}
+}
+
+/**
+ * fc_disc_gpn_ft_req - Send Get Port Names by FC-4 type (GPN_FT) request
+ * @lport: FC 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 = disc->lport;
+
+	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, NULL, fp,
+				 FC_NS_GPN_FT,
+				 fc_disc_gpn_ft_resp,
+				 disc, lport->e_d_tov))
+		return;
+err:
+	fc_disc_error(disc, fp);
+}
+
+/**
+ * fc_disc_gpn_ft_parse - Parse the list of IDs and names resulting from a request
+ * @lport: Fibre Channel host port instance
+ * @buf: GPN_FT response buffer
+ * @len: size of response buffer
+ */
+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_disc_port dp;
+	struct fc_rport *rport;
+	struct fc_rport_libfc_priv *rdata;
+
+	lport = disc->lport;
+
+	/*
+	 * Handle partial name record left over from previous call.
+	 */
+	bp = buf;
+	plen = len;
+	np = (struct fc_gpn_ft_resp *)bp;
+	tlen = disc->buf_len;
+	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)) {
+		dp.lp = lport;
+		dp.ids.port_id = ntoh24(np->fp_fid);
+		dp.ids.port_name = ntohll(np->fp_wwpn);
+		dp.ids.node_name = -1;
+		dp.ids.roles = FC_RPORT_ROLE_UNKNOWN;
+
+		if ((dp.ids.port_id != fc_host_port_id(lport->host)) &&
+		    (dp.ids.port_name != lport->wwpn)) {
+			rport = fc_rport_rogue_create(&dp);
+			if (rport) {
+				rdata = rport->dd_data;
+				rdata->ops = &fc_disc_rport_ops;
+				rdata->local_port = lport;
+				lport->tt.rport_login(rport);
+			} else
+				FC_DBG("Failed to allocate memory for "
+				       "the newly discovered port (%6x)\n",
+				       dp.ids.port_id);
+		}
+
+		if (np->fp_flags & FC_NS_FID_LAST) {
+			disc->event = DISC_EV_SUCCESS;
+			fc_disc_done(disc);
+			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_DEBUG_DISC("Partial buffer remains "
+				      "for discovery by (%6x)\n",
+				      fc_host_port_id(lport->host));
+			memcpy(&disc->partial_buf, np, len);
+		}
+		disc->buf_len = (unsigned char) len;
+	} else {
+		disc->buf_len = 0;
+	}
+	return error;
+}
+
+/*
+ * Handle retry of memory allocation for remote ports.
+ */
+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);
+	if (disc->requested && !disc->pending)
+		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: Current sequence of GPN_FT exchange
+ * @fp: response frame
+ * @lp_arg: Fibre Channel host port instance
+ *
+ * Locking Note: This function expects that the disc_mutex is locked
+ *		 before it is called.
+ */
+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;
+	unsigned int seq_cnt;
+	void *buf = NULL;
+	unsigned int len;
+	int error;
+
+	FC_DEBUG_DISC("Received a GPN_FT response on port (%6x)\n",
+		      fc_host_port_id(disc->lport->host));
+
+	if (IS_ERR(fp)) {
+		fc_disc_error(disc, fp);
+		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_DBG("GPN_FT response too short, len %d\n",
+			       fr_len(fp));
+		} else if (ntohs(cp->ct_cmd) == FC_FS_ACC) {
+
+			/*
+			 * Accepted.  Parse response.
+			 */
+			buf = cp + 1;
+			len -= sizeof(*cp);
+		} else if (ntohs(cp->ct_cmd) == FC_FS_RJT) {
+			FC_DBG("GPN_FT rejected reason %x exp %x "
+			       "(check zoning)\n", cp->ct_reason,
+			       cp->ct_explan);
+			disc->event = DISC_EV_FAILED;
+			fc_disc_done(disc);
+		} else {
+			FC_DBG("GPN_FT unexpected response code %x\n",
+			       ntohs(cp->ct_cmd));
+		}
+	} else if (fr_sof(fp) == FC_SOF_N3 &&
+		   seq_cnt == disc->seq_count) {
+		buf = fh + 1;
+	} else {
+		FC_DBG("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));
+	}
+	if (buf) {
+		error = fc_disc_gpn_ft_parse(disc, buf, len);
+		if (error)
+			fc_disc_error(disc, fp);
+		else
+			disc->seq_count++;
+	}
+	fc_frame_free(fp);
+}
+
+/**
+ * fc_disc_single - Discover the directory information for a single target
+ * @lport: FC local port
+ * @dp: The port to rediscover
+ *
+ * Locking Note: This function expects that the disc_mutex is locked
+ *		 before it is called.
+ */
+static void fc_disc_single(struct fc_disc *disc, struct fc_disc_port *dp)
+{
+	struct fc_lport *lport;
+	struct fc_rport *rport;
+	struct fc_rport *new_rport;
+	struct fc_rport_libfc_priv *rdata;
+
+	lport = disc->lport;
+
+	if (dp->ids.port_id == fc_host_port_id(lport->host))
+		goto out;
+
+	rport = lport->tt.rport_lookup(lport, dp->ids.port_id);
+	if (rport)
+		fc_disc_del_target(disc, rport);
+
+	new_rport = fc_rport_rogue_create(dp);
+	if (new_rport) {
+		rdata = new_rport->dd_data;
+		rdata->ops = &fc_disc_rport_ops;
+		kfree(dp);
+		lport->tt.rport_login(new_rport);
+	}
+	return;
+out:
+	kfree(dp);
+}
+
+/**
+ * fc_disc_stop - Stop discovery for a given lport
+ * @lport: The lport that discovery should stop for
+ */
+void fc_disc_stop(struct fc_lport *lport)
+{
+	struct fc_disc *disc = &lport->disc;
+
+	if (disc) {
+		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 for
+ *
+ * This function will block until discovery has been
+ * completely stopped and all rports have been deleted.
+ */
+void fc_disc_stop_final(struct fc_lport *lport)
+{
+	fc_disc_stop(lport);
+	lport->tt.rport_flush_queue();
+}
+
+/**
+ * fc_disc_init - Initialize the discovery block
+ * @lport: FC local port
+ */
+int fc_disc_init(struct fc_lport *lport)
+{
+	struct fc_disc *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;
+
+	if (!lport->tt.rport_lookup)
+		lport->tt.rport_lookup = fc_disc_lookup_rport;
+
+	disc = &lport->disc;
+	INIT_DELAYED_WORK(&disc->disc_work, fc_disc_timeout);
+	mutex_init(&disc->disc_mutex);
+	INIT_LIST_HEAD(&disc->rports);
+
+	disc->lport = lport;
+	disc->delay = FC_DISC_DELAY;
+	disc->event = DISC_EV_NONE;
+
+	return 0;
+}
+EXPORT_SYMBOL(fc_disc_init);