Linux Audio

Check our new training course

Embedded Linux Audio

Check our new training course
with Creative Commons CC-BY-SA
lecture materials

Bootlin logo

Elixir Cross Referencer

Loading...
  1
  2
  3
  4
  5
  6
  7
  8
  9
 10
 11
 12
 13
 14
 15
 16
 17
 18
 19
 20
 21
 22
 23
 24
 25
 26
 27
 28
 29
 30
 31
 32
 33
 34
 35
 36
 37
 38
 39
 40
 41
 42
 43
 44
 45
 46
 47
 48
 49
 50
 51
 52
 53
 54
 55
 56
 57
 58
 59
 60
 61
 62
 63
 64
 65
 66
 67
 68
 69
 70
 71
 72
 73
 74
 75
 76
 77
 78
 79
 80
 81
 82
 83
 84
 85
 86
 87
 88
 89
 90
 91
 92
 93
 94
 95
 96
 97
 98
 99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
427
428
429
430
431
432
433
434
435
436
437
438
439
440
441
442
443
444
445
446
447
448
449
450
451
452
453
454
455
456
457
458
459
460
461
462
463
464
465
466
467
468
469
470
471
472
473
474
475
476
477
478
479
480
481
482
483
484
485
486
487
488
489
490
491
492
493
494
495
496
497
498
499
500
501
502
503
504
505
506
507
508
509
510
511
512
513
514
515
516
517
518
519
520
521
522
523
524
525
526
527
528
529
530
531
532
533
534
535
536
537
538
539
540
541
542
543
544
545
546
547
548
549
550
551
552
553
554
555
556
557
558
559
560
561
562
563
564
565
566
567
568
569
570
571
572
573
574
575
576
577
578
579
580
581
582
583
584
585
586
587
588
589
590
591
592
593
594
595
596
597
598
599
600
601
602
603
604
605
606
607
608
609
610
611
612
613
614
615
616
617
618
619
620
621
622
623
624
625
626
627
628
629
630
631
632
633
634
635
636
637
638
639
640
641
642
643
644
645
646
647
648
649
650
651
652
653
654
655
656
657
658
659
660
661
662
663
664
665
666
667
668
669
670
671
672
673
674
675
676
677
678
679
680
681
682
683
684
685
686
687
688
689
690
691
692
693
694
695
696
697
698
699
700
701
702
703
704
705
706
707
708
709
710
711
712
713
714
715
716
717
718
719
720
721
722
723
724
725
726
727
728
729
730
731
732
733
734
735
736
737
738
739
740
741
742
743
744
745
746
747
748
749
750
751
752
753
754
755
756
757
758
759
760
761
762
763
764
765
766
767
768
769
770
771
772
773
774
775
776
777
778
779
780
781
782
783
784
785
786
787
788
789
790
791
792
793
794
795
796
797
798
799
800
801
802
803
804
805
806
807
808
809
810
811
812
813
814
815
816
817
818
819
820
821
822
823
824
825
826
827
828
829
830
831
832
833
834
835
836
837
838
839
840
841
842
843
844
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);