summaryrefslogtreecommitdiffstats
path: root/drivers/s390/scsi/zfcp_dbf.c
blob: dccdb41bed8c4d5cc6f4886adb76e0006f65e4cd (plain)
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
// SPDX-License-Identifier: GPL-2.0
/*
 * zfcp device driver
 *
 * Debug traces for zfcp.
 *
 * Copyright IBM Corp. 2002, 2018
 */

#define KMSG_COMPONENT "zfcp"
#define pr_fmt(fmt) KMSG_COMPONENT ": " fmt

#include <linux/module.h>
#include <linux/ctype.h>
#include <linux/slab.h>
#include <asm/debug.h>
#include "zfcp_dbf.h"
#include "zfcp_ext.h"
#include "zfcp_fc.h"

static u32 dbfsize = 4;

module_param(dbfsize, uint, 0400);
MODULE_PARM_DESC(dbfsize,
		 "number of pages for each debug feature area (default 4)");

static u32 dbflevel = 3;

module_param(dbflevel, uint, 0400);
MODULE_PARM_DESC(dbflevel,
		 "log level for each debug feature area "
		 "(default 3, range 0..6)");

static inline unsigned int zfcp_dbf_plen(unsigned int offset)
{
	return sizeof(struct zfcp_dbf_pay) + offset - ZFCP_DBF_PAY_MAX_REC;
}

static inline
void zfcp_dbf_pl_write(struct zfcp_dbf *dbf, void *data, u16 length, char *area,
		       u64 req_id)
{
	struct zfcp_dbf_pay *pl = &dbf->pay_buf;
	u16 offset = 0, rec_length;

	spin_lock(&dbf->pay_lock);
	memset(pl, 0, sizeof(*pl));
	pl->fsf_req_id = req_id;
	memcpy(pl->area, area, ZFCP_DBF_TAG_LEN);

	while (offset < length) {
		rec_length = min((u16) ZFCP_DBF_PAY_MAX_REC,
				 (u16) (length - offset));
		memcpy(pl->data, data + offset, rec_length);
		debug_event(dbf->pay, 1, pl, zfcp_dbf_plen(rec_length));

		offset += rec_length;
		pl->counter++;
	}

	spin_unlock(&dbf->pay_lock);
}

/**
 * zfcp_dbf_hba_fsf_res - trace event for fsf responses
 * @tag: tag indicating which kind of FSF response has been received
 * @level: trace level to be used for event
 * @req: request for which a response was received
 */
void zfcp_dbf_hba_fsf_res(char *tag, int level, struct zfcp_fsf_req *req)
{
	struct zfcp_dbf *dbf = req->adapter->dbf;
	struct fsf_qtcb_prefix *q_pref = &req->qtcb->prefix;
	struct fsf_qtcb_header *q_head = &req->qtcb->header;
	struct zfcp_dbf_hba *rec = &dbf->hba_buf;
	unsigned long flags;

	spin_lock_irqsave(&dbf->hba_lock, flags);
	memset(rec, 0, sizeof(*rec));

	memcpy(rec->tag, tag, ZFCP_DBF_TAG_LEN);
	rec->id = ZFCP_DBF_HBA_RES;
	rec->fsf_req_id = req->req_id;
	rec->fsf_req_status = req->status;
	rec->fsf_cmd = q_head->fsf_command;
	rec->fsf_seq_no = q_pref->req_seq_no;
	rec->u.res.req_issued = req->issued;
	rec->u.res.prot_status = q_pref->prot_status;
	rec->u.res.fsf_status = q_head->fsf_status;
	rec->u.res.port_handle = q_head->port_handle;
	rec->u.res.lun_handle = q_head->lun_handle;

	memcpy(rec->u.res.prot_status_qual, &q_pref->prot_status_qual,
	       FSF_PROT_STATUS_QUAL_SIZE);
	memcpy(rec->u.res.fsf_status_qual, &q_head->fsf_status_qual,
	       FSF_STATUS_QUALIFIER_SIZE);

	if (q_head->fsf_command != FSF_QTCB_FCP_CMND) {
		rec->pl_len = q_head->log_length;
		zfcp_dbf_pl_write(dbf, (char *)q_pref + q_head->log_start,
				  rec->pl_len, "fsf_res", req->req_id);
	}

	debug_event(dbf->hba, level, rec, sizeof(*rec));
	spin_unlock_irqrestore(&dbf->hba_lock, flags);
}

/**
 * zfcp_dbf_hba_fsf_uss - trace event for an unsolicited status buffer
 * @tag: tag indicating which kind of unsolicited status has been received
 * @req: request providing the unsolicited status
 */
void zfcp_dbf_hba_fsf_uss(char *tag, struct zfcp_fsf_req *req)
{
	struct zfcp_dbf *dbf = req->adapter->dbf;
	struct fsf_status_read_buffer *srb = req->data;
	struct zfcp_dbf_hba *rec = &dbf->hba_buf;
	static int const level = 2;
	unsigned long flags;

	if (unlikely(!debug_level_enabled(dbf->hba, level)))
		return;

	spin_lock_irqsave(&dbf->hba_lock, flags);
	memset(rec, 0, sizeof(*rec));

	memcpy(rec->tag, tag, ZFCP_DBF_TAG_LEN);
	rec->id = ZFCP_DBF_HBA_USS;
	rec->fsf_req_id = req->req_id;
	rec->fsf_req_status = req->status;
	rec->fsf_cmd = FSF_QTCB_UNSOLICITED_STATUS;

	if (!srb)
		goto log;

	rec->u.uss.status_type = srb->status_type;
	rec->u.uss.status_subtype = srb->status_subtype;
	rec->u.uss.d_id = ntoh24(srb->d_id);
	rec->u.uss.lun = srb->fcp_lun;
	memcpy(&rec->u.uss.queue_designator, &srb->queue_designator,
	       sizeof(rec->u.uss.queue_designator));

	/* status read buffer payload length */
	rec->pl_len = (!srb->length) ? 0 : srb->length -
			offsetof(struct fsf_status_read_buffer, payload);

	if (rec->pl_len)
		zfcp_dbf_pl_write(dbf, srb->payload.data, rec->pl_len,
				  "fsf_uss", req->req_id);
log:
	debug_event(dbf->hba, level, rec, sizeof(*rec));
	spin_unlock_irqrestore(&dbf->hba_lock, flags);
}

/**
 * zfcp_dbf_hba_bit_err - trace event for bit error conditions
 * @tag: tag indicating which kind of bit error unsolicited status was received
 * @req: request which caused the bit_error condition
 */
void zfcp_dbf_hba_bit_err(char *tag, struct zfcp_fsf_req *req)
{
	struct zfcp_dbf *dbf = req->adapter->dbf;
	struct zfcp_dbf_hba *rec = &dbf->hba_buf;
	struct fsf_status_read_buffer *sr_buf = req->data;
	static int const level = 1;
	unsigned long flags;

	if (unlikely(!debug_level_enabled(dbf->hba, level)))
		return;

	spin_lock_irqsave(&dbf->hba_lock, flags);
	memset(rec, 0, sizeof(*rec));

	memcpy(rec->tag, tag, ZFCP_DBF_TAG_LEN);
	rec->id = ZFCP_DBF_HBA_BIT;
	rec->fsf_req_id = req->req_id;
	rec->fsf_req_status = req->status;
	rec->fsf_cmd = FSF_QTCB_UNSOLICITED_STATUS;
	memcpy(&rec->u.be, &sr_buf->payload.bit_error,
	       sizeof(struct fsf_bit_error_payload));

	debug_event(dbf->hba, level, rec, sizeof(*rec));
	spin_unlock_irqrestore(&dbf->hba_lock, flags);
}

/**
 * zfcp_dbf_hba_def_err - trace event for deferred error messages
 * @adapter: pointer to struct zfcp_adapter
 * @req_id: request id which caused the deferred error message
 * @scount: number of sbals incl. the signaling sbal
 * @pl: array of all involved sbals
 */
void zfcp_dbf_hba_def_err(struct zfcp_adapter *adapter, u64 req_id, u16 scount,
			  void **pl)
{
	struct zfcp_dbf *dbf = adapter->dbf;
	struct zfcp_dbf_pay *payload = &dbf->pay_buf;
	unsigned long flags;
	static int const level = 1;
	u16 length;

	if (unlikely(!debug_level_enabled(dbf->pay, level)))
		return;

	if (!pl)
		return;

	spin_lock_irqsave(&dbf->pay_lock, flags);
	memset(payload, 0, sizeof(*payload));

	memcpy(payload->area, "def_err", 7);
	payload->fsf_req_id = req_id;
	payload->counter = 0;
	length = min((u16)sizeof(struct qdio_buffer),
		     (u16)ZFCP_DBF_PAY_MAX_REC);

	while (payload->counter < scount && (char *)pl[payload->counter]) {
		memcpy(payload->data, (char *)pl[payload->counter], length);
		debug_event(dbf->pay, level, payload, zfcp_dbf_plen(length));
		payload->counter++;
	}

	spin_unlock_irqrestore(&dbf->pay_lock, flags);
}

/**
 * zfcp_dbf_hba_basic - trace event for basic adapter events
 * @tag: identifier for event
 * @adapter: pointer to struct zfcp_adapter
 */
void zfcp_dbf_hba_basic(char *tag, struct zfcp_adapter *adapter)
{
	struct zfcp_dbf *dbf = adapter->dbf;
	struct zfcp_dbf_hba *rec = &dbf->hba_buf;
	static int const level = 1;
	unsigned long flags;

	if (unlikely(!debug_level_enabled(dbf->hba, level)))
		return;

	spin_lock_irqsave(&dbf->hba_lock, flags);
	memset(rec, 0, sizeof(*rec));

	memcpy(rec->tag, tag, ZFCP_DBF_TAG_LEN);
	rec->id = ZFCP_DBF_HBA_BASIC;

	debug_event(dbf->hba, level, rec, sizeof(*rec));
	spin_unlock_irqrestore(&dbf->hba_lock, flags);
}

static void zfcp_dbf_set_common(struct zfcp_dbf_rec *rec,
				struct zfcp_adapter *adapter,
				struct zfcp_port *port,
				struct scsi_device *sdev)
{
	rec->adapter_status = atomic_read(&adapter->status);
	if (port) {
		rec->port_status = atomic_read(&port->status);
		rec->wwpn = port->wwpn;
		rec->d_id = port->d_id;
	}
	if (sdev) {
		rec->lun_status = atomic_read(&sdev_to_zfcp(sdev)->status);
		rec->lun = zfcp_scsi_dev_lun(sdev);
	} else
		rec->lun = ZFCP_DBF_INVALID_LUN;
}

/**
 * zfcp_dbf_rec_trig - trace event related to triggered recovery
 * @tag: identifier for event
 * @adapter: adapter on which the erp_action should run
 * @port: remote port involved in the erp_action
 * @sdev: scsi device involved in the erp_action
 * @want: wanted erp_action
 * @need: required erp_action
 *
 * The adapter->erp_lock has to be held.
 */
void zfcp_dbf_rec_trig(char *tag, struct zfcp_adapter *adapter,
		       struct zfcp_port *port, struct scsi_device *sdev,
		       u8 want, u8 need)
{
	struct zfcp_dbf *dbf = adapter->dbf;
	struct zfcp_dbf_rec *rec = &dbf->rec_buf;
	static int const level = 1;
	struct list_head *entry;
	unsigned long flags;

	lockdep_assert_held(&adapter->erp_lock);

	if (unlikely(!debug_level_enabled(dbf->rec, level)))
		return;

	spin_lock_irqsave(&dbf->rec_lock, flags);
	memset(rec, 0, sizeof(*rec));

	rec->id = ZFCP_DBF_REC_TRIG;
	memcpy(rec->tag, tag, ZFCP_DBF_TAG_LEN);
	zfcp_dbf_set_common(rec, adapter, port, sdev);

	list_for_each(entry, &adapter->erp_ready_head)
		rec->u.trig.ready++;

	list_for_each(entry, &adapter->erp_running_head)
		rec->u.trig.running++;

	rec->u.trig.want = want;
	rec->u.trig.need = need;

	debug_event(dbf->rec, level, rec, sizeof(*rec));
	spin_unlock_irqrestore(&dbf->rec_lock, flags);
}

/**
 * zfcp_dbf_rec_trig_lock - trace event related to triggered recovery with lock
 * @tag: identifier for event
 * @adapter: adapter on which the erp_action should run
 * @port: remote port involved in the erp_action
 * @sdev: scsi device involved in the erp_action
 * @want: wanted erp_action
 * @need: required erp_action
 *
 * The adapter->erp_lock must not be held.
 */
void zfcp_dbf_rec_trig_lock(char *tag, struct zfcp_adapter *adapter,
			    struct zfcp_port *port, struct scsi_device *sdev,
			    u8 want, u8 need)
{
	unsigned long flags;

	read_lock_irqsave(&adapter->erp_lock, flags);
	zfcp_dbf_rec_trig(tag, adapter, port, sdev, want, need);
	read_unlock_irqrestore(&adapter->erp_lock, flags);
}

/**
 * zfcp_dbf_rec_run_lvl - trace event related to running recovery
 * @level: trace level to be used for event
 * @tag: identifier for event
 * @erp: erp_action running
 */
void zfcp_dbf_rec_run_lvl(int level, char *tag, struct zfcp_erp_action *erp)
{
	struct zfcp_dbf *dbf = erp->adapter->dbf;
	struct zfcp_dbf_rec *rec = &dbf->rec_buf;
	unsigned long flags;

	if (!debug_level_enabled(dbf->rec, level))
		return;

	spin_lock_irqsave(&dbf->rec_lock, flags);
	memset(rec, 0, sizeof(*rec));

	rec->id = ZFCP_DBF_REC_RUN;
	memcpy(rec->tag, tag, ZFCP_DBF_TAG_LEN);
	zfcp_dbf_set_common(rec, erp->adapter, erp->port, erp->sdev);

	rec->u.run.fsf_req_id = erp->fsf_req_id;
	rec->u.run.rec_status = erp->status;
	rec->u.run.rec_step = erp->step;
	rec->u.run.rec_action = erp->type;

	if (erp->sdev)
		rec->u.run.rec_count =
			atomic_read(&sdev_to_zfcp(erp->sdev)->erp_counter);
	else if (erp->port)
		rec->u.run.rec_count = atomic_read(&erp->port->erp_counter);
	else
		rec->u.run.rec_count = atomic_read(&erp->adapter->erp_counter);

	debug_event(dbf->rec, level, rec, sizeof(*rec));
	spin_unlock_irqrestore(&dbf->rec_lock, flags);
}

/**
 * zfcp_dbf_rec_run - trace event related to running recovery
 * @tag: identifier for event
 * @erp: erp_action running
 */
void zfcp_dbf_rec_run(char *tag, struct zfcp_erp_action *erp)
{
	zfcp_dbf_rec_run_lvl(1, tag, erp);
}

/**
 * zfcp_dbf_rec_run_wka - trace wka port event with info like running recovery
 * @tag: identifier for event
 * @wka_port: well known address port
 * @req_id: request ID to correlate with potential HBA trace record
 */
void zfcp_dbf_rec_run_wka(char *tag, struct zfcp_fc_wka_port *wka_port,
			  u64 req_id)
{
	struct zfcp_dbf *dbf = wka_port->adapter->dbf;
	struct zfcp_dbf_rec *rec = &dbf->rec_buf;
	static int const level = 1;
	unsigned long flags;

	if (unlikely(!debug_level_enabled(dbf->rec, level)))
		return;

	spin_lock_irqsave(&dbf->rec_lock, flags);
	memset(rec, 0, sizeof(*rec));

	rec->id = ZFCP_DBF_REC_RUN;
	memcpy(rec->tag, tag, ZFCP_DBF_TAG_LEN);
	rec->port_status = wka_port->status;
	rec->d_id = wka_port->d_id;
	rec->lun = ZFCP_DBF_INVALID_LUN;

	rec->u.run.fsf_req_id = req_id;
	rec->u.run.rec_status = ~0;
	rec->u.run.rec_step = ~0;
	rec->u.run.rec_action = ~0;
	rec->u.run.rec_count = ~0;

	debug_event(dbf->rec, level, rec, sizeof(*rec));
	spin_unlock_irqrestore(&dbf->rec_lock, flags);
}

#define ZFCP_DBF_SAN_LEVEL 1

static inline
void zfcp_dbf_san(char *tag, struct zfcp_dbf *dbf,
		  char *paytag, struct scatterlist *sg, u8 id, u16 len,
		  u64 req_id, u32 d_id, u16 cap_len)
{
	struct zfcp_dbf_san *rec = &dbf->san_buf;
	u16 rec_len;
	unsigned long flags;
	struct zfcp_dbf_pay *payload = &dbf->pay_buf;
	u16 pay_sum = 0;

	spin_lock_irqsave(&dbf->san_lock, flags);
	memset(rec, 0, sizeof(*rec));

	rec->id = id;
	rec->fsf_req_id = req_id;
	rec->d_id = d_id;
	memcpy(rec->tag, tag, ZFCP_DBF_TAG_LEN);
	rec->pl_len = len; /* full length even if we cap pay below */
	if (!sg)
		goto out;
	rec_len = min_t(unsigned int, sg->length, ZFCP_DBF_SAN_MAX_PAYLOAD);
	memcpy(rec->payload, sg_virt(sg), rec_len); /* part of 1st sg entry */
	if (len <= rec_len)
		goto out; /* skip pay record if full content in rec->payload */

	/* if (len > rec_len):
	 * dump data up to cap_len ignoring small duplicate in rec->payload
	 */
	spin_lock(&dbf->pay_lock);
	memset(payload, 0, sizeof(*payload));
	memcpy(payload->area, paytag, ZFCP_DBF_TAG_LEN);
	payload->fsf_req_id = req_id;
	payload->counter = 0;
	for (; sg && pay_sum < cap_len; sg = sg_next(sg)) {
		u16 pay_len, offset = 0;

		while (offset < sg->length && pay_sum < cap_len) {
			pay_len = min((u16)ZFCP_DBF_PAY_MAX_REC,
				      (u16)(sg->length - offset));
			/* cap_len <= pay_sum < cap_len+ZFCP_DBF_PAY_MAX_REC */
			memcpy(payload->data, sg_virt(sg) + offset, pay_len);
			debug_event(dbf->pay, ZFCP_DBF_SAN_LEVEL, payload,
				    zfcp_dbf_plen(pay_len));
			payload->counter++;
			offset += pay_len;
			pay_sum += pay_len;
		}
	}
	spin_unlock(&dbf->pay_lock);

out:
	debug_event(dbf->san, ZFCP_DBF_SAN_LEVEL, rec, sizeof(*rec));
	spin_unlock_irqrestore(&dbf->san_lock, flags);
}

/**
 * zfcp_dbf_san_req - trace event for issued SAN request
 * @tag: identifier for event
 * @fsf: request containing issued CT or ELS data
 * @d_id: N_Port_ID where SAN request is sent to
 * d_id: destination ID
 */
void zfcp_dbf_san_req(char *tag, struct zfcp_fsf_req *fsf, u32 d_id)
{
	struct zfcp_dbf *dbf = fsf->adapter->dbf;
	struct zfcp_fsf_ct_els *ct_els = fsf->data;
	u16 length;

	if (unlikely(!debug_level_enabled(dbf->san, ZFCP_DBF_SAN_LEVEL)))
		return;

	length = (u16)zfcp_qdio_real_bytes(ct_els->req);
	zfcp_dbf_san(tag, dbf, "san_req", ct_els->req, ZFCP_DBF_SAN_REQ,
		     length, fsf->req_id, d_id, length);
}

static u16 zfcp_dbf_san_res_cap_len_if_gpn_ft(char *tag,
					      struct zfcp_fsf_req *fsf,
					      u16 len)
{
	struct zfcp_fsf_ct_els *ct_els = fsf->data;
	struct fc_ct_hdr *reqh = sg_virt(ct_els->req);
	struct fc_ns_gid_ft *reqn = (struct fc_ns_gid_ft *)(reqh + 1);
	struct scatterlist *resp_entry = ct_els->resp;
	struct fc_ct_hdr *resph;
	struct fc_gpn_ft_resp *acc;
	int max_entries, x, last = 0;

	if (!(memcmp(tag, "fsscth2", 7) == 0
	      && ct_els->d_id == FC_FID_DIR_SERV
	      && reqh->ct_rev == FC_CT_REV
	      && reqh->ct_in_id[0] == 0
	      && reqh->ct_in_id[1] == 0
	      && reqh->ct_in_id[2] == 0
	      && reqh->ct_fs_type == FC_FST_DIR
	      && reqh->ct_fs_subtype == FC_NS_SUBTYPE
	      && reqh->ct_options == 0
	      && reqh->_ct_resvd1 == 0
	      && reqh->ct_cmd == cpu_to_be16(FC_NS_GPN_FT)
	      /* reqh->ct_mr_size can vary so do not match but read below */
	      && reqh->_ct_resvd2 == 0
	      && reqh->ct_reason == 0
	      && reqh->ct_explan == 0
	      && reqh->ct_vendor == 0
	      && reqn->fn_resvd == 0
	      && reqn->fn_domain_id_scope == 0
	      && reqn->fn_area_id_scope == 0
	      && reqn->fn_fc4_type == FC_TYPE_FCP))
		return len; /* not GPN_FT response so do not cap */

	acc = sg_virt(resp_entry);

	/* cap all but accept CT responses to at least the CT header */
	resph = (struct fc_ct_hdr *)acc;
	if ((ct_els->status) ||
	    (resph->ct_cmd != cpu_to_be16(FC_FS_ACC)))
		return max(FC_CT_HDR_LEN, ZFCP_DBF_SAN_MAX_PAYLOAD);

	max_entries = (be16_to_cpu(reqh->ct_mr_size) * 4 /
		       sizeof(struct fc_gpn_ft_resp))
		+ 1 /* zfcp_fc_scan_ports: bytes correct, entries off-by-one
		     * to account for header as 1st pseudo "entry" */;

	/* the basic CT_IU preamble is the same size as one entry in the GPN_FT
	 * response, allowing us to skip special handling for it - just skip it
	 */
	for (x = 1; x < max_entries && !last; x++) {
		if (x % (ZFCP_FC_GPN_FT_ENT_PAGE + 1))
			acc++;
		else
			acc = sg_virt(++resp_entry);

		last = acc->fp_flags & FC_NS_FID_LAST;
	}
	len = min(len, (u16)(x * sizeof(struct fc_gpn_ft_resp)));
	return len; /* cap after last entry */
}

/**
 * zfcp_dbf_san_res - trace event for received SAN request
 * @tag: identifier for event
 * @fsf: request containing received CT or ELS data
 */
void zfcp_dbf_san_res(char *tag, struct zfcp_fsf_req *fsf)
{
	struct zfcp_dbf *dbf = fsf->adapter->dbf;
	struct zfcp_fsf_ct_els *ct_els = fsf->data;
	u16 length;

	if (unlikely(!debug_level_enabled(dbf->san, ZFCP_DBF_SAN_LEVEL)))
		return;

	length = (u16)zfcp_qdio_real_bytes(ct_els->resp);
	zfcp_dbf_san(tag, dbf, "san_res", ct_els->resp, ZFCP_DBF_SAN_RES,
		     length, fsf->req_id, ct_els->d_id,
		     zfcp_dbf_san_res_cap_len_if_gpn_ft(tag, fsf, length));
}

/**
 * zfcp_dbf_san_in_els - trace event for incoming ELS
 * @tag: identifier for event
 * @fsf: request containing received ELS data
 */
void zfcp_dbf_san_in_els(char *tag, struct zfcp_fsf_req *fsf)
{
	struct zfcp_dbf *dbf = fsf->adapter->dbf;
	struct fsf_status_read_buffer *srb =
		(struct fsf_status_read_buffer *) fsf->data;
	u16 length;
	struct scatterlist sg;

	if (unlikely(!debug_level_enabled(dbf->san, ZFCP_DBF_SAN_LEVEL)))
		return;

	length = (u16)(srb->length -
			offsetof(struct fsf_status_read_buffer, payload));
	sg_init_one(&sg, srb->payload.data, length);
	zfcp_dbf_san(tag, dbf, "san_els", &sg, ZFCP_DBF_SAN_ELS, length,
		     fsf->req_id, ntoh24(srb->d_id), length);
}

/**
 * zfcp_dbf_scsi_common() - Common trace event helper for scsi.
 * @tag: Identifier for event.
 * @level: trace level of event.
 * @sdev: Pointer to SCSI device as context for this event.
 * @sc: Pointer to SCSI command, or NULL with task management function (TMF).
 * @fsf: Pointer to FSF request, or NULL.
 */
void zfcp_dbf_scsi_common(char *tag, int level, struct scsi_device *sdev,
			  struct scsi_cmnd *sc, struct zfcp_fsf_req *fsf)
{
	struct zfcp_adapter *adapter =
		(struct zfcp_adapter *) sdev->host->hostdata[0];
	struct zfcp_dbf *dbf = adapter->dbf;
	struct zfcp_dbf_scsi *rec = &dbf->scsi_buf;
	struct fcp_resp_with_ext *fcp_rsp;
	struct fcp_resp_rsp_info *fcp_rsp_info;
	unsigned long flags;

	spin_lock_irqsave(&dbf->scsi_lock, flags);
	memset(rec, 0, sizeof(*rec));

	memcpy(rec->tag, tag, ZFCP_DBF_TAG_LEN);
	rec->id = ZFCP_DBF_SCSI_CMND;
	if (sc) {
		rec->scsi_result = sc->result;
		rec->scsi_retries = sc->retries;
		rec->scsi_allowed = sc->allowed;
		rec->scsi_id = sc->device->id;
		rec->scsi_lun = (u32)sc->device->lun;
		rec->scsi_lun_64_hi = (u32)(sc->device->lun >> 32);
		rec->host_scribble = (unsigned long)sc->host_scribble;

		memcpy(rec->scsi_opcode, sc->cmnd,
		       min_t(int, sc->cmd_len, ZFCP_DBF_SCSI_OPCODE));
	} else {
		rec->scsi_result = ~0;
		rec->scsi_retries = ~0;
		rec->scsi_allowed = ~0;
		rec->scsi_id = sdev->id;
		rec->scsi_lun = (u32)sdev->lun;
		rec->scsi_lun_64_hi = (u32)(sdev->lun >> 32);
		rec->host_scribble = ~0;

		memset(rec->scsi_opcode, 0xff, ZFCP_DBF_SCSI_OPCODE);
	}

	if (fsf) {
		rec->fsf_req_id = fsf->req_id;
		rec->pl_len = FCP_RESP_WITH_EXT;
		fcp_rsp = &(fsf->qtcb->bottom.io.fcp_rsp.iu);
		/* mandatory parts of FCP_RSP IU in this SCSI record */
		memcpy(&rec->fcp_rsp, fcp_rsp, FCP_RESP_WITH_EXT);
		if (fcp_rsp->resp.fr_flags & FCP_RSP_LEN_VAL) {
			fcp_rsp_info = (struct fcp_resp_rsp_info *) &fcp_rsp[1];
			rec->fcp_rsp_info = fcp_rsp_info->rsp_code;
			rec->pl_len += be32_to_cpu(fcp_rsp->ext.fr_rsp_len);
		}
		if (fcp_rsp->resp.fr_flags & FCP_SNS_LEN_VAL) {
			rec->pl_len += be32_to_cpu(fcp_rsp->ext.fr_sns_len);
		}
		/* complete FCP_RSP IU in associated PAYload record
		 * but only if there are optional parts
		 */
		if (fcp_rsp->resp.fr_flags != 0)
			zfcp_dbf_pl_write(
				dbf, fcp_rsp,
				/* at least one full PAY record
				 * but not beyond hardware response field
				 */
				min_t(u16, max_t(u16, rec->pl_len,
						 ZFCP_DBF_PAY_MAX_REC),
				      FSF_FCP_RSP_SIZE),
				"fcp_riu", fsf->req_id);
	}

	debug_event(dbf->scsi, level, rec, sizeof(*rec));
	spin_unlock_irqrestore(&dbf->scsi_lock, flags);
}

/**
 * zfcp_dbf_scsi_eh() - Trace event for special cases of scsi_eh callbacks.
 * @tag: Identifier for event.
 * @adapter: Pointer to zfcp adapter as context for this event.
 * @scsi_id: SCSI ID/target to indicate scope of task management function (TMF).
 * @ret: Return value of calling function.
 *
 * This SCSI trace variant does not depend on any of:
 * scsi_cmnd, zfcp_fsf_req, scsi_device.
 */
void zfcp_dbf_scsi_eh(char *tag, struct zfcp_adapter *adapter,
		      unsigned int scsi_id, int ret)
{
	struct zfcp_dbf *dbf = adapter->dbf;
	struct zfcp_dbf_scsi *rec = &dbf->scsi_buf;
	unsigned long flags;
	static int const level = 1;

	if (unlikely(!debug_level_enabled(adapter->dbf->scsi, level)))
		return;

	spin_lock_irqsave(&dbf->scsi_lock, flags);
	memset(rec, 0, sizeof(*rec));

	memcpy(rec->tag, tag, ZFCP_DBF_TAG_LEN);
	rec->id = ZFCP_DBF_SCSI_CMND;
	rec->scsi_result = ret; /* re-use field, int is 4 bytes and fits */
	rec->scsi_retries = ~0;
	rec->scsi_allowed = ~0;
	rec->fcp_rsp_info = ~0;
	rec->scsi_id = scsi_id;
	rec->scsi_lun = (u32)ZFCP_DBF_INVALID_LUN;
	rec->scsi_lun_64_hi = (u32)(ZFCP_DBF_INVALID_LUN >> 32);
	rec->host_scribble = ~0;
	memset(rec->scsi_opcode, 0xff, ZFCP_DBF_SCSI_OPCODE);

	debug_event(dbf->scsi, level, rec, sizeof(*rec));
	spin_unlock_irqrestore(&dbf->scsi_lock, flags);
}

static debug_info_t *zfcp_dbf_reg(const char *name, int size, int rec_size)
{
	struct debug_info *d;

	d = debug_register(name, size, 1, rec_size);
	if (!d)
		return NULL;

	debug_register_view(d, &debug_hex_ascii_view);
	debug_set_level(d, dbflevel);

	return d;
}

static void zfcp_dbf_unregister(struct zfcp_dbf *dbf)
{
	if (!dbf)
		return;

	debug_unregister(dbf->scsi);
	debug_unregister(dbf->san);
	debug_unregister(dbf->hba);
	debug_unregister(dbf->pay);
	debug_unregister(dbf->rec);
	kfree(dbf);
}

/**
 * zfcp_adapter_debug_register - registers debug feature for an adapter
 * @adapter: pointer to adapter for which debug features should be registered
 * return: -ENOMEM on error, 0 otherwise
 */
int zfcp_dbf_adapter_register(struct zfcp_adapter *adapter)
{
	char name[DEBUG_MAX_NAME_LEN];
	struct zfcp_dbf *dbf;

	dbf = kzalloc(sizeof(struct zfcp_dbf), GFP_KERNEL);
	if (!dbf)
		return -ENOMEM;

	spin_lock_init(&dbf->pay_lock);
	spin_lock_init(&dbf->hba_lock);
	spin_lock_init(&dbf->san_lock);
	spin_lock_init(&dbf->scsi_lock);
	spin_lock_init(&dbf->rec_lock);

	/* debug feature area which records recovery activity */
	sprintf(name, "zfcp_%s_rec", dev_name(&adapter->ccw_device->dev));
	dbf->rec = zfcp_dbf_reg(name, dbfsize, sizeof(struct zfcp_dbf_rec));
	if (!dbf->rec)
		goto err_out;

	/* debug feature area which records HBA (FSF and QDIO) conditions */
	sprintf(name, "zfcp_%s_hba", dev_name(&adapter->ccw_device->dev));
	dbf->hba = zfcp_dbf_reg(name, dbfsize, sizeof(struct zfcp_dbf_hba));
	if (!dbf->hba)
		goto err_out;

	/* debug feature area which records payload info */
	sprintf(name, "zfcp_%s_pay", dev_name(&adapter->ccw_device->dev));
	dbf->pay = zfcp_dbf_reg(name, dbfsize * 2, sizeof(struct zfcp_dbf_pay));
	if (!dbf->pay)
		goto err_out;

	/* debug feature area which records SAN command failures and recovery */
	sprintf(name, "zfcp_%s_san", dev_name(&adapter->ccw_device->dev));
	dbf->san = zfcp_dbf_reg(name, dbfsize, sizeof(struct zfcp_dbf_san));
	if (!dbf->san)
		goto err_out;

	/* debug feature area which records SCSI command failures and recovery */
	sprintf(name, "zfcp_%s_scsi", dev_name(&adapter->ccw_device->dev));
	dbf->scsi = zfcp_dbf_reg(name, dbfsize, sizeof(struct zfcp_dbf_scsi));
	if (!dbf->scsi)
		goto err_out;

	adapter->dbf = dbf;

	return 0;
err_out:
	zfcp_dbf_unregister(dbf);
	return -ENOMEM;
}

/**
 * zfcp_adapter_debug_unregister - unregisters debug feature for an adapter
 * @adapter: pointer to adapter for which debug features should be unregistered
 */
void zfcp_dbf_adapter_unregister(struct zfcp_adapter *adapter)
{
	struct zfcp_dbf *dbf = adapter->dbf;

	adapter->dbf = NULL;
	zfcp_dbf_unregister(dbf);
}