[SCSI] libfc: send GPN_ID in reaction to single-port RSCNs.

When an RSCN indicates changes to individual remote ports,
don't blindly log them out and then back in.  Instead, determine
whether they're still in the directory, by doing GPN_ID.

If that is successful, call login, which will send ADISC and reverify,
otherwise, call logoff.  Perhaps we should just delete the rport,
not send LOGO, but it seems safer.

Also, fix a possible issue where if a mix of records in the RSCN
cause us to queue disc_ports for disc_single and then we decide
to do full rediscovery, we leak memory for those disc_ports queued.

So, go through the list of disc_ports even if doing full discovery.
Free the disc_ports in any case.  If any of the disc_single() calls
return error, do a full discovery.

The ability to fill in GPN_ID requests was added to fc_ct_fill().
For this, it needs the FC_ID to be passed in as an arg.
The did parameter for fc_elsct_send() is used for that, since the
actual D_DID will always be 0xfffffc for all CT requests so far.
Signed-off-by: Joe Eykholt <jeykholt@cisco.com>
Signed-off-by: Robert Love <robert.w.love@intel.com>
Signed-off-by: James Bottomley <James.Bottomley@suse.de>

drivers/scsi/libfc/fc_disc.c

@@ -47,7 +47,7 @@ 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 void fc_disc_single(struct fc_disc *, struct fc_disc_port *);
+static int fc_disc_single(struct fc_lport *, struct fc_disc_port *);
 static void fc_disc_restart(struct fc_disc *);
 
 /**
@@ -83,7 +83,6 @@ 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_priv *rdata;
 	struct fc_els_rscn *rp;
 	struct fc_els_rscn_page *pp;
 	struct fc_seq_els_data rjt_data;
@@ -150,6 +149,19 @@ static void fc_disc_recv_rscn_req(struct fc_seq *sp, struct fc_frame *fp,
 		}
 	}
 	lport->tt.seq_els_rsp_send(sp, 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);
@@ -157,14 +169,6 @@ static void fc_disc_recv_rscn_req(struct fc_seq *sp, struct fc_frame *fp,
 		FC_DISC_DBG(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);
-			rdata = lport->tt.rport_lookup(lport, dp->port_id);
-			if (rdata) {
-				lport->tt.rport_logoff(rdata);
-			}
-			fc_disc_single(disc, dp);
-		}
 	}
 	fc_frame_free(fp);
 	return;
@@ -562,32 +566,117 @@ static void fc_disc_gpn_ft_resp(struct fc_seq *sp, struct fc_frame *fp,
 }
 
 /**
- * fc_disc_single() - Discover the directory information for a single target
- * @lport: FC local port
- * @dp: The port to rediscover
+ * fc_disc_gpn_id_resp() - Handle a response frame from Get Port Names (GPN_ID)
+ * @sp: exchange sequence
+ * @fp: response frame
+ * @rdata_arg: remote port private data
  *
- * Locking Note: This function expects that the disc_mutex is locked
- *		 before it is called.
+ * Locking Note: This function is called without disc mutex held.
  */
-static void fc_disc_single(struct fc_disc *disc, struct fc_disc_port *dp)
+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_rport_priv *rdata;
+	struct fc_disc *disc;
+	struct fc_ct_hdr *cp;
+	struct fc_ns_gid_pn *pn;
+	u64 port_name;
 
-	lport = disc->lport;
+	lport = rdata->local_port;
+	disc = &lport->disc;
 
-	if (dp->port_id == fc_host_port_id(lport->host))
+	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 %x wwpn %llx\n",
+				    rdata->ids.port_id, port_name);
+			lport->tt.rport_logoff(rdata);
 
-	rdata = lport->tt.rport_create(lport, dp->port_id);
-	if (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;
-		kfree(dp);
 		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);
 	}
-	return;
 out:
-	kfree(dp);
+	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: local port
+ * @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, lport->e_d_tov))
+		return -ENOMEM;
+	kref_get(&rdata->kref);
+	return 0;
+}
+
+/**
+ * fc_disc_single() - Discover the directory information for a single target
+ * @lport: local port
+ * @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);
 }
 
 /**

drivers/scsi/libfc/fc_elsct.c

@@ -49,7 +49,7 @@ static struct fc_seq *fc_elsct_send(struct fc_lport *lport,
 		rc = fc_els_fill(lport, did, fp, op, &r_ctl, &fh_type);
 	else {
 		/* CT requests */
-		rc = fc_ct_fill(lport, fp, op, &r_ctl, &fh_type);
+		rc = fc_ct_fill(lport, did, fp, op, &r_ctl, &fh_type);
 		did = FC_FID_DIR_SERV;
 	}
 

include/scsi/fc_encode.h

@@ -32,6 +32,7 @@ struct fc_ct_req {
 		struct fc_ns_gid_ft gid;
 		struct fc_ns_rn_id  rn;
 		struct fc_ns_rft rft;
+		struct fc_ns_fid fid;
 	} payload;
 };
 
@@ -94,10 +95,16 @@ static inline struct fc_ct_req *fc_ct_hdr_fill(const struct fc_frame *fp,
 }
 
 /**
- * fc_ct_fill - Fill in a name service request frame
+ * fc_ct_fill() - Fill in a name service request frame
+ * @lport: local port.
+ * @fc_id: FC_ID of non-destination rport for GPN_ID and similar inquiries.
+ * @fp: frame to contain payload.
+ * @op: CT opcode.
+ * @r_ctl: pointer to FC header R_CTL.
+ * @fh_type: pointer to FC-4 type.
  */
 static inline int fc_ct_fill(struct fc_lport *lport,
-		      struct fc_frame *fp,
+		      u32 fc_id, struct fc_frame *fp,
 		      unsigned int op, enum fc_rctl *r_ctl,
 		      enum fc_fh_type *fh_type)
 {
@@ -109,6 +116,11 @@ static inline int fc_ct_fill(struct fc_lport *lport,
 		ct->payload.gid.fn_fc4_type = FC_TYPE_FCP;
 		break;
 
+	case FC_NS_GPN_ID:
+		ct = fc_ct_hdr_fill(fp, op, sizeof(struct fc_ns_fid));
+		hton24(ct->payload.fid.fp_fid, fc_id);
+		break;
+
 	case FC_NS_RFT_ID:
 		ct = fc_ct_hdr_fill(fp, op, sizeof(struct fc_ns_rft));
 		hton24(ct->payload.rft.fid.fp_fid,