summaryrefslogtreecommitdiffstats
path: root/drivers/scsi/device_handler/scsi_dh_rdac.c
blob: 826069db9848e08d1b928986387484f23da5abdb (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
823
824
825
826
827
828
829
830
831
832
833
834
835
836
837
838
839
840
841
842
843
844
845
846
847
848
849
850
851
852
853
854
855
856
857
858
859
860
861
862
863
864
865
866
867
868
869
870
871
872
873
874
875
876
877
878
879
880
881
882
883
884
885
886
887
888
889
890
891
892
893
894
895
896
897
898
899
900
901
902
903
904
905
906
907
908
909
910
911
912
913
914
915
916
917
918
919
920
921
922
923
924
925
926
927
928
929
930
931
932
933
934
935
936
937
938
939
940
941
942
943
944
945
946
947
948
949
950
951
952
953
954
955
956
957
958
959
960
961
962
963
964
965
966
967
968
969
/*
 * LSI/Engenio/NetApp E-Series RDAC SCSI Device Handler
 *
 * Copyright (C) 2005 Mike Christie. All rights reserved.
 * Copyright (C) Chandra Seetharaman, IBM Corp. 2007
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation; either version 2 of the License, or
 * (at your option) any later version.
 *
 * This program is distributed in the hope that 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., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
 *
 */
#include <scsi/scsi.h>
#include <scsi/scsi_eh.h>
#include <scsi/scsi_dh.h>
#include <linux/workqueue.h>
#include <linux/slab.h>
#include <linux/module.h>

#define RDAC_NAME "rdac"
#define RDAC_RETRY_COUNT 5

/*
 * LSI mode page stuff
 *
 * These struct definitions and the forming of the
 * mode page were taken from the LSI RDAC 2.4 GPL'd
 * driver, and then converted to Linux conventions.
 */
#define RDAC_QUIESCENCE_TIME 20
/*
 * Page Codes
 */
#define RDAC_PAGE_CODE_REDUNDANT_CONTROLLER 0x2c

/*
 * Controller modes definitions
 */
#define RDAC_MODE_TRANSFER_SPECIFIED_LUNS	0x02

/*
 * RDAC Options field
 */
#define RDAC_FORCED_QUIESENCE 0x02

#define RDAC_TIMEOUT	(60 * HZ)
#define RDAC_RETRIES	3

struct rdac_mode_6_hdr {
	u8	data_len;
	u8	medium_type;
	u8	device_params;
	u8	block_desc_len;
};

struct rdac_mode_10_hdr {
	u16	data_len;
	u8	medium_type;
	u8	device_params;
	u16	reserved;
	u16	block_desc_len;
};

struct rdac_mode_common {
	u8	controller_serial[16];
	u8	alt_controller_serial[16];
	u8	rdac_mode[2];
	u8	alt_rdac_mode[2];
	u8	quiescence_timeout;
	u8	rdac_options;
};

struct rdac_pg_legacy {
	struct rdac_mode_6_hdr hdr;
	u8	page_code;
	u8	page_len;
	struct rdac_mode_common common;
#define MODE6_MAX_LUN	32
	u8	lun_table[MODE6_MAX_LUN];
	u8	reserved2[32];
	u8	reserved3;
	u8	reserved4;
};

struct rdac_pg_expanded {
	struct rdac_mode_10_hdr hdr;
	u8	page_code;
	u8	subpage_code;
	u8	page_len[2];
	struct rdac_mode_common common;
	u8	lun_table[256];
	u8	reserved3;
	u8	reserved4;
};

struct c9_inquiry {
	u8	peripheral_info;
	u8	page_code;	/* 0xC9 */
	u8	reserved1;
	u8	page_len;
	u8	page_id[4];	/* "vace" */
	u8	avte_cvp;
	u8	path_prio;
	u8	reserved2[38];
};

#define SUBSYS_ID_LEN	16
#define SLOT_ID_LEN	2
#define ARRAY_LABEL_LEN	31

struct c4_inquiry {
	u8	peripheral_info;
	u8	page_code;	/* 0xC4 */
	u8	reserved1;
	u8	page_len;
	u8	page_id[4];	/* "subs" */
	u8	subsys_id[SUBSYS_ID_LEN];
	u8	revision[4];
	u8	slot_id[SLOT_ID_LEN];
	u8	reserved[2];
};

#define UNIQUE_ID_LEN 16
struct c8_inquiry {
	u8	peripheral_info;
	u8	page_code; /* 0xC8 */
	u8	reserved1;
	u8	page_len;
	u8	page_id[4]; /* "edid" */
	u8	reserved2[3];
	u8	vol_uniq_id_len;
	u8	vol_uniq_id[16];
	u8	vol_user_label_len;
	u8	vol_user_label[60];
	u8	array_uniq_id_len;
	u8	array_unique_id[UNIQUE_ID_LEN];
	u8	array_user_label_len;
	u8	array_user_label[60];
	u8	lun[8];
};

struct rdac_controller {
	u8			array_id[UNIQUE_ID_LEN];
	int			use_ms10;
	struct kref		kref;
	struct list_head	node; /* list of all controllers */
	union			{
		struct rdac_pg_legacy legacy;
		struct rdac_pg_expanded expanded;
	} mode_select;
	u8	index;
	u8	array_name[ARRAY_LABEL_LEN];
	struct Scsi_Host	*host;
	spinlock_t		ms_lock;
	int			ms_queued;
	struct work_struct	ms_work;
	struct scsi_device	*ms_sdev;
	struct list_head	ms_head;
};

struct c2_inquiry {
	u8	peripheral_info;
	u8	page_code;	/* 0xC2 */
	u8	reserved1;
	u8	page_len;
	u8	page_id[4];	/* "swr4" */
	u8	sw_version[3];
	u8	sw_date[3];
	u8	features_enabled;
	u8	max_lun_supported;
	u8	partitions[239]; /* Total allocation length should be 0xFF */
};

struct rdac_dh_data {
	struct rdac_controller	*ctlr;
#define UNINITIALIZED_LUN	(1 << 8)
	unsigned		lun;

#define RDAC_MODE		0
#define RDAC_MODE_AVT		1
#define RDAC_MODE_IOSHIP	2
	unsigned char		mode;

#define RDAC_STATE_ACTIVE	0
#define RDAC_STATE_PASSIVE	1
	unsigned char		state;

#define RDAC_LUN_UNOWNED	0
#define RDAC_LUN_OWNED		1
	char			lun_state;

#define RDAC_PREFERRED		0
#define RDAC_NON_PREFERRED	1
	char			preferred;

	unsigned char		sense[SCSI_SENSE_BUFFERSIZE];
	union			{
		struct c2_inquiry c2;
		struct c4_inquiry c4;
		struct c8_inquiry c8;
		struct c9_inquiry c9;
	} inq;
};

static const char *mode[] = {
	"RDAC",
	"AVT",
	"IOSHIP",
};
static const char *lun_state[] =
{
	"unowned",
	"owned",
};

struct rdac_queue_data {
	struct list_head	entry;
	struct rdac_dh_data	*h;
	activate_complete	callback_fn;
	void			*callback_data;
};

static LIST_HEAD(ctlr_list);
static DEFINE_SPINLOCK(list_lock);
static struct workqueue_struct *kmpath_rdacd;
static void send_mode_select(struct work_struct *work);

/*
 * module parameter to enable rdac debug logging.
 * 2 bits for each type of logging, only two types defined for now
 * Can be enhanced if required at later point
 */
static int rdac_logging = 1;
module_param(rdac_logging, int, S_IRUGO|S_IWUSR);
MODULE_PARM_DESC(rdac_logging, "A bit mask of rdac logging levels, "
		"Default is 1 - failover logging enabled, "
		"set it to 0xF to enable all the logs");

#define RDAC_LOG_FAILOVER	0
#define RDAC_LOG_SENSE		2

#define RDAC_LOG_BITS		2

#define RDAC_LOG_LEVEL(SHIFT)  \
	((rdac_logging >> (SHIFT)) & ((1 << (RDAC_LOG_BITS)) - 1))

#define RDAC_LOG(SHIFT, sdev, f, arg...) \
do { \
	if (unlikely(RDAC_LOG_LEVEL(SHIFT))) \
		sdev_printk(KERN_INFO, sdev, RDAC_NAME ": " f "\n", ## arg); \
} while (0);

static inline struct rdac_dh_data *get_rdac_data(struct scsi_device *sdev)
{
	struct scsi_dh_data *scsi_dh_data = sdev->scsi_dh_data;
	BUG_ON(scsi_dh_data == NULL);
	return ((struct rdac_dh_data *) scsi_dh_data->buf);
}

static struct request *get_rdac_req(struct scsi_device *sdev,
			void *buffer, unsigned buflen, int rw)
{
	struct request *rq;
	struct request_queue *q = sdev->request_queue;

	rq = blk_get_request(q, rw, GFP_NOIO);

	if (!rq) {
		sdev_printk(KERN_INFO, sdev,
				"get_rdac_req: blk_get_request failed.\n");
		return NULL;
	}
	blk_rq_set_block_pc(rq);

	if (buflen && blk_rq_map_kern(q, rq, buffer, buflen, GFP_NOIO)) {
		blk_put_request(rq);
		sdev_printk(KERN_INFO, sdev,
				"get_rdac_req: blk_rq_map_kern failed.\n");
		return NULL;
	}

	rq->cmd_flags |= REQ_FAILFAST_DEV | REQ_FAILFAST_TRANSPORT |
			 REQ_FAILFAST_DRIVER;
	rq->retries = RDAC_RETRIES;
	rq->timeout = RDAC_TIMEOUT;

	return rq;
}

static struct request *rdac_failover_get(struct scsi_device *sdev,
			struct rdac_dh_data *h, struct list_head *list)
{
	struct request *rq;
	struct rdac_mode_common *common;
	unsigned data_size;
	struct rdac_queue_data *qdata;
	u8 *lun_table;

	if (h->ctlr->use_ms10) {
		struct rdac_pg_expanded *rdac_pg;

		data_size = sizeof(struct rdac_pg_expanded);
		rdac_pg = &h->ctlr->mode_select.expanded;
		memset(rdac_pg, 0, data_size);
		common = &rdac_pg->common;
		rdac_pg->page_code = RDAC_PAGE_CODE_REDUNDANT_CONTROLLER + 0x40;
		rdac_pg->subpage_code = 0x1;
		rdac_pg->page_len[0] = 0x01;
		rdac_pg->page_len[1] = 0x28;
		lun_table = rdac_pg->lun_table;
	} else {
		struct rdac_pg_legacy *rdac_pg;

		data_size = sizeof(struct rdac_pg_legacy);
		rdac_pg = &h->ctlr->mode_select.legacy;
		memset(rdac_pg, 0, data_size);
		common = &rdac_pg->common;
		rdac_pg->page_code = RDAC_PAGE_CODE_REDUNDANT_CONTROLLER;
		rdac_pg->page_len = 0x68;
		lun_table = rdac_pg->lun_table;
	}
	common->rdac_mode[1] = RDAC_MODE_TRANSFER_SPECIFIED_LUNS;
	common->quiescence_timeout = RDAC_QUIESCENCE_TIME;
	common->rdac_options = RDAC_FORCED_QUIESENCE;

	list_for_each_entry(qdata, list, entry) {
		lun_table[qdata->h->lun] = 0x81;
	}

	/* get request for block layer packet command */
	rq = get_rdac_req(sdev, &h->ctlr->mode_select, data_size, WRITE);
	if (!rq)
		return NULL;

	/* Prepare the command. */
	if (h->ctlr->use_ms10) {
		rq->cmd[0] = MODE_SELECT_10;
		rq->cmd[7] = data_size >> 8;
		rq->cmd[8] = data_size & 0xff;
	} else {
		rq->cmd[0] = MODE_SELECT;
		rq->cmd[4] = data_size;
	}
	rq->cmd_len = COMMAND_SIZE(rq->cmd[0]);

	rq->sense = h->sense;
	memset(rq->sense, 0, SCSI_SENSE_BUFFERSIZE);
	rq->sense_len = 0;

	return rq;
}

static void release_controller(struct kref *kref)
{
	struct rdac_controller *ctlr;
	ctlr = container_of(kref, struct rdac_controller, kref);

	list_del(&ctlr->node);
	kfree(ctlr);
}

static struct rdac_controller *get_controller(int index, char *array_name,
			u8 *array_id, struct scsi_device *sdev)
{
	struct rdac_controller *ctlr, *tmp;

	list_for_each_entry(tmp, &ctlr_list, node) {
		if ((memcmp(tmp->array_id, array_id, UNIQUE_ID_LEN) == 0) &&
			  (tmp->index == index) &&
			  (tmp->host == sdev->host)) {
			kref_get(&tmp->kref);
			return tmp;
		}
	}
	ctlr = kmalloc(sizeof(*ctlr), GFP_ATOMIC);
	if (!ctlr)
		return NULL;

	/* initialize fields of controller */
	memcpy(ctlr->array_id, array_id, UNIQUE_ID_LEN);
	ctlr->index = index;
	ctlr->host = sdev->host;
	memcpy(ctlr->array_name, array_name, ARRAY_LABEL_LEN);

	kref_init(&ctlr->kref);
	ctlr->use_ms10 = -1;
	ctlr->ms_queued = 0;
	ctlr->ms_sdev = NULL;
	spin_lock_init(&ctlr->ms_lock);
	INIT_WORK(&ctlr->ms_work, send_mode_select);
	INIT_LIST_HEAD(&ctlr->ms_head);
	list_add(&ctlr->node, &ctlr_list);

	return ctlr;
}

static int submit_inquiry(struct scsi_device *sdev, int page_code,
			  unsigned int len, struct rdac_dh_data *h)
{
	struct request *rq;
	struct request_queue *q = sdev->request_queue;
	int err = SCSI_DH_RES_TEMP_UNAVAIL;

	rq = get_rdac_req(sdev, &h->inq, len, READ);
	if (!rq)
		goto done;

	/* Prepare the command. */
	rq->cmd[0] = INQUIRY;
	rq->cmd[1] = 1;
	rq->cmd[2] = page_code;
	rq->cmd[4] = len;
	rq->cmd_len = COMMAND_SIZE(INQUIRY);

	rq->sense = h->sense;
	memset(rq->sense, 0, SCSI_SENSE_BUFFERSIZE);
	rq->sense_len = 0;

	err = blk_execute_rq(q, NULL, rq, 1);
	if (err == -EIO)
		err = SCSI_DH_IO;

	blk_put_request(rq);
done:
	return err;
}

static int get_lun_info(struct scsi_device *sdev, struct rdac_dh_data *h,
			char *array_name, u8 *array_id)
{
	int err, i;
	struct c8_inquiry *inqp;

	err = submit_inquiry(sdev, 0xC8, sizeof(struct c8_inquiry), h);
	if (err == SCSI_DH_OK) {
		inqp = &h->inq.c8;
		if (inqp->page_code != 0xc8)
			return SCSI_DH_NOSYS;
		if (inqp->page_id[0] != 'e' || inqp->page_id[1] != 'd' ||
		    inqp->page_id[2] != 'i' || inqp->page_id[3] != 'd')
			return SCSI_DH_NOSYS;
		h->lun = inqp->lun[7]; /* Uses only the last byte */

		for(i=0; i<ARRAY_LABEL_LEN-1; ++i)
			*(array_name+i) = inqp->array_user_label[(2*i)+1];

		*(array_name+ARRAY_LABEL_LEN-1) = '\0';
		memset(array_id, 0, UNIQUE_ID_LEN);
		memcpy(array_id, inqp->array_unique_id, inqp->array_uniq_id_len);
	}
	return err;
}

static int check_ownership(struct scsi_device *sdev, struct rdac_dh_data *h)
{
	int err;
	struct c9_inquiry *inqp;

	h->state = RDAC_STATE_ACTIVE;
	err = submit_inquiry(sdev, 0xC9, sizeof(struct c9_inquiry), h);
	if (err == SCSI_DH_OK) {
		inqp = &h->inq.c9;
		/* detect the operating mode */
		if ((inqp->avte_cvp >> 5) & 0x1)
			h->mode = RDAC_MODE_IOSHIP; /* LUN in IOSHIP mode */
		else if (inqp->avte_cvp >> 7)
			h->mode = RDAC_MODE_AVT; /* LUN in AVT mode */
		else
			h->mode = RDAC_MODE; /* LUN in RDAC mode */

		/* Update ownership */
		if (inqp->avte_cvp & 0x1)
			h->lun_state = RDAC_LUN_OWNED;
		else {
			h->lun_state = RDAC_LUN_UNOWNED;
			if (h->mode == RDAC_MODE)
				h->state = RDAC_STATE_PASSIVE;
		}

		/* Update path prio*/
		if (inqp->path_prio & 0x1)
			h->preferred = RDAC_PREFERRED;
		else
			h->preferred = RDAC_NON_PREFERRED;
	}

	return err;
}

static int initialize_controller(struct scsi_device *sdev,
		struct rdac_dh_data *h, char *array_name, u8 *array_id)
{
	int err, index;
	struct c4_inquiry *inqp;

	err = submit_inquiry(sdev, 0xC4, sizeof(struct c4_inquiry), h);
	if (err == SCSI_DH_OK) {
		inqp = &h->inq.c4;
		/* get the controller index */
		if (inqp->slot_id[1] == 0x31)
			index = 0;
		else
			index = 1;

		spin_lock(&list_lock);
		h->ctlr = get_controller(index, array_name, array_id, sdev);
		if (!h->ctlr)
			err = SCSI_DH_RES_TEMP_UNAVAIL;
		spin_unlock(&list_lock);
	}
	return err;
}

static int set_mode_select(struct scsi_device *sdev, struct rdac_dh_data *h)
{
	int err;
	struct c2_inquiry *inqp;

	err = submit_inquiry(sdev, 0xC2, sizeof(struct c2_inquiry), h);
	if (err == SCSI_DH_OK) {
		inqp = &h->inq.c2;
		/*
		 * If more than MODE6_MAX_LUN luns are supported, use
		 * mode select 10
		 */
		if (inqp->max_lun_supported >= MODE6_MAX_LUN)
			h->ctlr->use_ms10 = 1;
		else
			h->ctlr->use_ms10 = 0;
	}
	return err;
}

static int mode_select_handle_sense(struct scsi_device *sdev,
					unsigned char *sensebuf)
{
	struct scsi_sense_hdr sense_hdr;
	int err = SCSI_DH_IO, ret;
	struct rdac_dh_data *h = get_rdac_data(sdev);

	ret = scsi_normalize_sense(sensebuf, SCSI_SENSE_BUFFERSIZE, &sense_hdr);
	if (!ret)
		goto done;

	switch (sense_hdr.sense_key) {
	case NO_SENSE:
	case ABORTED_COMMAND:
	case UNIT_ATTENTION:
		err = SCSI_DH_RETRY;
		break;
	case NOT_READY:
		if (sense_hdr.asc == 0x04 && sense_hdr.ascq == 0x01)
			/* LUN Not Ready and is in the Process of Becoming
			 * Ready
			 */
			err = SCSI_DH_RETRY;
		break;
	case ILLEGAL_REQUEST:
		if (sense_hdr.asc == 0x91 && sense_hdr.ascq == 0x36)
			/*
			 * Command Lock contention
			 */
			err = SCSI_DH_RETRY;
		break;
	default:
		break;
	}

	RDAC_LOG(RDAC_LOG_FAILOVER, sdev, "array %s, ctlr %d, "
		"MODE_SELECT returned with sense %02x/%02x/%02x",
		(char *) h->ctlr->array_name, h->ctlr->index,
		sense_hdr.sense_key, sense_hdr.asc, sense_hdr.ascq);

done:
	return err;
}

static void send_mode_select(struct work_struct *work)
{
	struct rdac_controller *ctlr =
		container_of(work, struct rdac_controller, ms_work);
	struct request *rq;
	struct scsi_device *sdev = ctlr->ms_sdev;
	struct rdac_dh_data *h = get_rdac_data(sdev);
	struct request_queue *q = sdev->request_queue;
	int err, retry_cnt = RDAC_RETRY_COUNT;
	struct rdac_queue_data *tmp, *qdata;
	LIST_HEAD(list);

	spin_lock(&ctlr->ms_lock);
	list_splice_init(&ctlr->ms_head, &list);
	ctlr->ms_queued = 0;
	ctlr->ms_sdev = NULL;
	spin_unlock(&ctlr->ms_lock);

retry:
	err = SCSI_DH_RES_TEMP_UNAVAIL;
	rq = rdac_failover_get(sdev, h, &list);
	if (!rq)
		goto done;

	RDAC_LOG(RDAC_LOG_FAILOVER, sdev, "array %s, ctlr %d, "
		"%s MODE_SELECT command",
		(char *) h->ctlr->array_name, h->ctlr->index,
		(retry_cnt == RDAC_RETRY_COUNT) ? "queueing" : "retrying");

	err = blk_execute_rq(q, NULL, rq, 1);
	blk_put_request(rq);
	if (err != SCSI_DH_OK) {
		err = mode_select_handle_sense(sdev, h->sense);
		if (err == SCSI_DH_RETRY && retry_cnt--)
			goto retry;
	}
	if (err == SCSI_DH_OK) {
		h->state = RDAC_STATE_ACTIVE;
		RDAC_LOG(RDAC_LOG_FAILOVER, sdev, "array %s, ctlr %d, "
				"MODE_SELECT completed",
				(char *) h->ctlr->array_name, h->ctlr->index);
	}

done:
	list_for_each_entry_safe(qdata, tmp, &list, entry) {
		list_del(&qdata->entry);
		if (err == SCSI_DH_OK)
			qdata->h->state = RDAC_STATE_ACTIVE;
		if (qdata->callback_fn)
			qdata->callback_fn(qdata->callback_data, err);
		kfree(qdata);
	}
	return;
}

static int queue_mode_select(struct scsi_device *sdev,
				activate_complete fn, void *data)
{
	struct rdac_queue_data *qdata;
	struct rdac_controller *ctlr;

	qdata = kzalloc(sizeof(*qdata), GFP_KERNEL);
	if (!qdata)
		return SCSI_DH_RETRY;

	qdata->h = get_rdac_data(sdev);
	qdata->callback_fn = fn;
	qdata->callback_data = data;

	ctlr = qdata->h->ctlr;
	spin_lock(&ctlr->ms_lock);
	list_add_tail(&qdata->entry, &ctlr->ms_head);
	if (!ctlr->ms_queued) {
		ctlr->ms_queued = 1;
		ctlr->ms_sdev = sdev;
		queue_work(kmpath_rdacd, &ctlr->ms_work);
	}
	spin_unlock(&ctlr->ms_lock);
	return SCSI_DH_OK;
}

static int rdac_activate(struct scsi_device *sdev,
			activate_complete fn, void *data)
{
	struct rdac_dh_data *h = get_rdac_data(sdev);
	int err = SCSI_DH_OK;
	int act = 0;

	err = check_ownership(sdev, h);
	if (err != SCSI_DH_OK)
		goto done;

	switch (h->mode) {
	case RDAC_MODE:
		if (h->lun_state == RDAC_LUN_UNOWNED)
			act = 1;
		break;
	case RDAC_MODE_IOSHIP:
		if ((h->lun_state == RDAC_LUN_UNOWNED) &&
		    (h->preferred == RDAC_PREFERRED))
			act = 1;
		break;
	default:
		break;
	}

	if (act) {
		err = queue_mode_select(sdev, fn, data);
		if (err == SCSI_DH_OK)
			return 0;
	}
done:
	if (fn)
		fn(data, err);
	return 0;
}

static int rdac_prep_fn(struct scsi_device *sdev, struct request *req)
{
	struct rdac_dh_data *h = get_rdac_data(sdev);
	int ret = BLKPREP_OK;

	if (h->state != RDAC_STATE_ACTIVE) {
		ret = BLKPREP_KILL;
		req->cmd_flags |= REQ_QUIET;
	}
	return ret;

}

static int rdac_check_sense(struct scsi_device *sdev,
				struct scsi_sense_hdr *sense_hdr)
{
	struct rdac_dh_data *h = get_rdac_data(sdev);

	RDAC_LOG(RDAC_LOG_SENSE, sdev, "array %s, ctlr %d, "
			"I/O returned with sense %02x/%02x/%02x",
			(char *) h->ctlr->array_name, h->ctlr->index,
			sense_hdr->sense_key, sense_hdr->asc, sense_hdr->ascq);

	switch (sense_hdr->sense_key) {
	case NOT_READY:
		if (sense_hdr->asc == 0x04 && sense_hdr->ascq == 0x01)
			/* LUN Not Ready - Logical Unit Not Ready and is in
			* the process of becoming ready
			* Just retry.
			*/
			return ADD_TO_MLQUEUE;
		if (sense_hdr->asc == 0x04 && sense_hdr->ascq == 0x81)
			/* LUN Not Ready - Storage firmware incompatible
			 * Manual code synchonisation required.
			 *
			 * Nothing we can do here. Try to bypass the path.
			 */
			return SUCCESS;
		if (sense_hdr->asc == 0x04 && sense_hdr->ascq == 0xA1)
			/* LUN Not Ready - Quiescense in progress
			 *
			 * Just retry and wait.
			 */
			return ADD_TO_MLQUEUE;
		if (sense_hdr->asc == 0xA1  && sense_hdr->ascq == 0x02)
			/* LUN Not Ready - Quiescense in progress
			 * or has been achieved
			 * Just retry.
			 */
			return ADD_TO_MLQUEUE;
		break;
	case ILLEGAL_REQUEST:
		if (sense_hdr->asc == 0x94 && sense_hdr->ascq == 0x01) {
			/* Invalid Request - Current Logical Unit Ownership.
			 * Controller is not the current owner of the LUN,
			 * Fail the path, so that the other path be used.
			 */
			h->state = RDAC_STATE_PASSIVE;
			return SUCCESS;
		}
		break;
	case UNIT_ATTENTION:
		if (sense_hdr->asc == 0x29 && sense_hdr->ascq == 0x00)
			/*
			 * Power On, Reset, or Bus Device Reset, just retry.
			 */
			return ADD_TO_MLQUEUE;
		if (sense_hdr->asc == 0x8b && sense_hdr->ascq == 0x02)
			/*
			 * Quiescence in progress , just retry.
			 */
			return ADD_TO_MLQUEUE;
		break;
	}
	/* success just means we do not care what scsi-ml does */
	return SCSI_RETURN_NOT_HANDLED;
}

static const struct scsi_dh_devlist rdac_dev_list[] = {
	{"IBM", "1722"},
	{"IBM", "1724"},
	{"IBM", "1726"},
	{"IBM", "1742"},
	{"IBM", "1745"},
	{"IBM", "1746"},
	{"IBM", "1813"},
	{"IBM", "1814"},
	{"IBM", "1815"},
	{"IBM", "1818"},
	{"IBM", "3526"},
	{"SGI", "TP9"},
	{"SGI", "IS"},
	{"STK", "OPENstorage D280"},
	{"STK", "FLEXLINE 380"},
	{"SUN", "CSM"},
	{"SUN", "LCSM100"},
	{"SUN", "STK6580_6780"},
	{"SUN", "SUN_6180"},
	{"SUN", "ArrayStorage"},
	{"DELL", "MD3"},
	{"NETAPP", "INF-01-00"},
	{"LSI", "INF-01-00"},
	{"ENGENIO", "INF-01-00"},
	{NULL, NULL},
};

static bool rdac_match(struct scsi_device *sdev)
{
	int i;

	if (scsi_device_tpgs(sdev))
		return false;

	for (i = 0; rdac_dev_list[i].vendor; i++) {
		if (!strncmp(sdev->vendor, rdac_dev_list[i].vendor,
			strlen(rdac_dev_list[i].vendor)) &&
		    !strncmp(sdev->model, rdac_dev_list[i].model,
			strlen(rdac_dev_list[i].model))) {
			return true;
		}
	}
	return false;
}

static int rdac_bus_attach(struct scsi_device *sdev);
static void rdac_bus_detach(struct scsi_device *sdev);

static struct scsi_device_handler rdac_dh = {
	.name = RDAC_NAME,
	.module = THIS_MODULE,
	.devlist = rdac_dev_list,
	.prep_fn = rdac_prep_fn,
	.check_sense = rdac_check_sense,
	.attach = rdac_bus_attach,
	.detach = rdac_bus_detach,
	.activate = rdac_activate,
	.match = rdac_match,
};

static int rdac_bus_attach(struct scsi_device *sdev)
{
	struct scsi_dh_data *scsi_dh_data;
	struct rdac_dh_data *h;
	unsigned long flags;
	int err;
	char array_name[ARRAY_LABEL_LEN];
	char array_id[UNIQUE_ID_LEN];

	scsi_dh_data = kzalloc(sizeof(*scsi_dh_data)
			       + sizeof(*h) , GFP_KERNEL);
	if (!scsi_dh_data) {
		sdev_printk(KERN_ERR, sdev, "%s: Attach failed\n",
			    RDAC_NAME);
		return -ENOMEM;
	}

	scsi_dh_data->scsi_dh = &rdac_dh;
	h = (struct rdac_dh_data *) scsi_dh_data->buf;
	h->lun = UNINITIALIZED_LUN;
	h->state = RDAC_STATE_ACTIVE;

	err = get_lun_info(sdev, h, array_name, array_id);
	if (err != SCSI_DH_OK)
		goto failed;

	err = initialize_controller(sdev, h, array_name, array_id);
	if (err != SCSI_DH_OK)
		goto failed;

	err = check_ownership(sdev, h);
	if (err != SCSI_DH_OK)
		goto clean_ctlr;

	err = set_mode_select(sdev, h);
	if (err != SCSI_DH_OK)
		goto clean_ctlr;

	if (!try_module_get(THIS_MODULE))
		goto clean_ctlr;

	spin_lock_irqsave(sdev->request_queue->queue_lock, flags);
	sdev->scsi_dh_data = scsi_dh_data;
	spin_unlock_irqrestore(sdev->request_queue->queue_lock, flags);

	sdev_printk(KERN_NOTICE, sdev,
		    "%s: LUN %d (%s) (%s)\n",
		    RDAC_NAME, h->lun, mode[(int)h->mode],
		    lun_state[(int)h->lun_state]);

	return 0;

clean_ctlr:
	spin_lock(&list_lock);
	kref_put(&h->ctlr->kref, release_controller);
	spin_unlock(&list_lock);

failed:
	kfree(scsi_dh_data);
	sdev_printk(KERN_ERR, sdev, "%s: not attached\n",
		    RDAC_NAME);
	return -EINVAL;
}

static void rdac_bus_detach( struct scsi_device *sdev )
{
	struct scsi_dh_data *scsi_dh_data;
	struct rdac_dh_data *h;
	unsigned long flags;

	scsi_dh_data = sdev->scsi_dh_data;
	h = (struct rdac_dh_data *) scsi_dh_data->buf;
	if (h->ctlr && h->ctlr->ms_queued)
		flush_workqueue(kmpath_rdacd);

	spin_lock_irqsave(sdev->request_queue->queue_lock, flags);
	sdev->scsi_dh_data = NULL;
	spin_unlock_irqrestore(sdev->request_queue->queue_lock, flags);

	spin_lock(&list_lock);
	if (h->ctlr)
		kref_put(&h->ctlr->kref, release_controller);
	spin_unlock(&list_lock);
	kfree(scsi_dh_data);
	module_put(THIS_MODULE);
	sdev_printk(KERN_NOTICE, sdev, "%s: Detached\n", RDAC_NAME);
}



static int __init rdac_init(void)
{
	int r;

	r = scsi_register_device_handler(&rdac_dh);
	if (r != 0) {
		printk(KERN_ERR "Failed to register scsi device handler.");
		goto done;
	}

	/*
	 * Create workqueue to handle mode selects for rdac
	 */
	kmpath_rdacd = create_singlethread_workqueue("kmpath_rdacd");
	if (!kmpath_rdacd) {
		scsi_unregister_device_handler(&rdac_dh);
		printk(KERN_ERR "kmpath_rdacd creation failed.\n");

		r = -EINVAL;
	}
done:
	return r;
}

static void __exit rdac_exit(void)
{
	destroy_workqueue(kmpath_rdacd);
	scsi_unregister_device_handler(&rdac_dh);
}

module_init(rdac_init);
module_exit(rdac_exit);

MODULE_DESCRIPTION("Multipath LSI/Engenio/NetApp E-Series RDAC driver");
MODULE_AUTHOR("Mike Christie, Chandra Seetharaman");
MODULE_VERSION("01.00.0000.0000");
MODULE_LICENSE("GPL");