Free Electrons

Embedded Linux Experts

  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
/*
 * Target driver for EMC CLARiiON AX/CX-series hardware.
 * Based on code from Lars Marowsky-Bree <lmb@suse.de>
 * and Ed Goggin <egoggin@emc.com>.
 *
 * Copyright (C) 2006 Red Hat, Inc.  All rights reserved.
 * Copyright (C) 2006 Mike Christie
 *
 * 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, 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; see the file COPYING.  If not, write to
 * the Free Software Foundation, 675 Mass Ave, Cambridge, MA 02139, USA.
 */
#include <linux/slab.h>
#include <linux/module.h>
#include <scsi/scsi.h>
#include <scsi/scsi_eh.h>
#include <scsi/scsi_dh.h>
#include <scsi/scsi_device.h>

#define CLARIION_NAME			"emc"

#define CLARIION_TRESPASS_PAGE		0x22
#define CLARIION_BUFFER_SIZE		0xFC
#define CLARIION_TIMEOUT		(60 * HZ)
#define CLARIION_RETRIES		3
#define CLARIION_UNBOUND_LU		-1
#define CLARIION_SP_A			0
#define CLARIION_SP_B			1

/* Flags */
#define CLARIION_SHORT_TRESPASS		1
#define CLARIION_HONOR_RESERVATIONS	2

/* LUN states */
#define CLARIION_LUN_UNINITIALIZED	-1
#define CLARIION_LUN_UNBOUND		0
#define CLARIION_LUN_BOUND		1
#define CLARIION_LUN_OWNED		2

static unsigned char long_trespass[] = {
	0, 0, 0, 0, 0, 0, 0, 0,
	CLARIION_TRESPASS_PAGE,	/* Page code */
	0x09,			/* Page length - 2 */
	0x01,			/* Trespass code */
	0xff, 0xff,		/* Trespass target */
	0, 0, 0, 0, 0, 0	/* Reserved bytes / unknown */
};

static unsigned char short_trespass[] = {
	0, 0, 0, 0,
	CLARIION_TRESPASS_PAGE,	/* Page code */
	0x02,			/* Page length - 2 */
	0x01,			/* Trespass code */
	0xff,			/* Trespass target */
};

static const char * lun_state[] =
{
    "not bound",
    "bound",
    "owned",
};

struct clariion_dh_data {
	/*
	 * Flags:
	 *  CLARIION_SHORT_TRESPASS
	 * Use short trespass command (FC-series) or the long version
	 * (default for AX/CX CLARiiON arrays).
	 *
	 *  CLARIION_HONOR_RESERVATIONS
	 * Whether or not (default) to honor SCSI reservations when
	 * initiating a switch-over.
	 */
	unsigned flags;
	/*
	 * I/O buffer for both MODE_SELECT and INQUIRY commands.
	 */
	unsigned char buffer[CLARIION_BUFFER_SIZE];
	/*
	 * SCSI sense buffer for commands -- assumes serial issuance
	 * and completion sequence of all commands for same multipath.
	 */
	unsigned char sense[SCSI_SENSE_BUFFERSIZE];
	unsigned int senselen;
	/*
	 * LUN state
	 */
	int lun_state;
	/*
	 * SP Port number
	 */
	int port;
	/*
	 * which SP (A=0,B=1,UNBOUND=-1) is the default SP for this
	 * path's mapped LUN
	 */
	int default_sp;
	/*
	 * which SP (A=0,B=1,UNBOUND=-1) is the active SP for this
	 * path's mapped LUN
	 */
	int current_sp;
};

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

/*
 * Parse MODE_SELECT cmd reply.
 */
static int trespass_endio(struct scsi_device *sdev, char *sense)
{
	int err = SCSI_DH_IO;
	struct scsi_sense_hdr sshdr;

	if (!scsi_normalize_sense(sense, SCSI_SENSE_BUFFERSIZE, &sshdr)) {
		sdev_printk(KERN_ERR, sdev, "%s: Found valid sense data 0x%2x, "
			    "0x%2x, 0x%2x while sending CLARiiON trespass "
			    "command.\n", CLARIION_NAME, sshdr.sense_key,
			    sshdr.asc, sshdr.ascq);

		if ((sshdr.sense_key == 0x05) && (sshdr.asc == 0x04) &&
		     (sshdr.ascq == 0x00)) {
			/*
			 * Array based copy in progress -- do not send
			 * mode_select or copy will be aborted mid-stream.
			 */
			sdev_printk(KERN_INFO, sdev, "%s: Array Based Copy in "
				    "progress while sending CLARiiON trespass "
				    "command.\n", CLARIION_NAME);
			err = SCSI_DH_DEV_TEMP_BUSY;
		} else if ((sshdr.sense_key == 0x02) && (sshdr.asc == 0x04) &&
			    (sshdr.ascq == 0x03)) {
			/*
			 * LUN Not Ready - Manual Intervention Required
			 * indicates in-progress ucode upgrade (NDU).
			 */
			sdev_printk(KERN_INFO, sdev, "%s: Detected in-progress "
				    "ucode upgrade NDU operation while sending "
				    "CLARiiON trespass command.\n", CLARIION_NAME);
			err = SCSI_DH_DEV_TEMP_BUSY;
		} else
			err = SCSI_DH_DEV_FAILED;
	} else {
		sdev_printk(KERN_INFO, sdev,
			    "%s: failed to send MODE SELECT, no sense available\n",
			    CLARIION_NAME);
	}
	return err;
}

static int parse_sp_info_reply(struct scsi_device *sdev,
			       struct clariion_dh_data *csdev)
{
	int err = SCSI_DH_OK;

	/* check for in-progress ucode upgrade (NDU) */
	if (csdev->buffer[48] != 0) {
		sdev_printk(KERN_NOTICE, sdev, "%s: Detected in-progress "
			    "ucode upgrade NDU operation while finding "
			    "current active SP.", CLARIION_NAME);
		err = SCSI_DH_DEV_TEMP_BUSY;
		goto out;
	}
	if (csdev->buffer[4] > 2) {
		/* Invalid buffer format */
		sdev_printk(KERN_NOTICE, sdev,
			    "%s: invalid VPD page 0xC0 format\n",
			    CLARIION_NAME);
		err = SCSI_DH_NOSYS;
		goto out;
	}
	switch (csdev->buffer[28] & 0x0f) {
	case 6:
		sdev_printk(KERN_NOTICE, sdev,
			    "%s: ALUA failover mode detected\n",
			    CLARIION_NAME);
		break;
	case 4:
		/* Linux failover */
		break;
	default:
		sdev_printk(KERN_WARNING, sdev,
			    "%s: Invalid failover mode %d\n",
			    CLARIION_NAME, csdev->buffer[28] & 0x0f);
		err = SCSI_DH_NOSYS;
		goto out;
	}

	csdev->default_sp = csdev->buffer[5];
	csdev->lun_state = csdev->buffer[4];
	csdev->current_sp = csdev->buffer[8];
	csdev->port = csdev->buffer[7];

out:
	return err;
}

#define emc_default_str "FC (Legacy)"

static char * parse_sp_model(struct scsi_device *sdev, unsigned char *buffer)
{
	unsigned char len = buffer[4] + 5;
	char *sp_model = NULL;
	unsigned char sp_len, serial_len;

	if (len < 160) {
		sdev_printk(KERN_WARNING, sdev,
			    "%s: Invalid information section length %d\n",
			    CLARIION_NAME, len);
		/* Check for old FC arrays */
		if (!strncmp(buffer + 8, "DGC", 3)) {
			/* Old FC array, not supporting extended information */
			sp_model = emc_default_str;
		}
		goto out;
	}

	/*
	 * Parse extended information for SP model number
	 */
	serial_len = buffer[160];
	if (serial_len == 0 || serial_len + 161 > len) {
		sdev_printk(KERN_WARNING, sdev,
			    "%s: Invalid array serial number length %d\n",
			    CLARIION_NAME, serial_len);
		goto out;
	}
	sp_len = buffer[99];
	if (sp_len == 0 || serial_len + sp_len + 161 > len) {
		sdev_printk(KERN_WARNING, sdev,
			    "%s: Invalid model number length %d\n",
			    CLARIION_NAME, sp_len);
		goto out;
	}
	sp_model = &buffer[serial_len + 161];
	/* Strip whitespace at the end */
	while (sp_len > 1 && sp_model[sp_len - 1] == ' ')
		sp_len--;

	sp_model[sp_len] = '\0';

out:
	return sp_model;
}

/*
 * Get block request for REQ_BLOCK_PC command issued to path.  Currently
 * limited to MODE_SELECT (trespass) and INQUIRY (VPD page 0xC0) commands.
 *
 * Uses data and sense buffers in hardware handler context structure and
 * assumes serial servicing of commands, both issuance and completion.
 */
static struct request *get_req(struct scsi_device *sdev, int cmd,
				unsigned char *buffer)
{
	struct request *rq;
	int len = 0;

	rq = blk_get_request(sdev->request_queue,
			(cmd != INQUIRY) ? WRITE : READ, GFP_NOIO);
	if (!rq) {
		sdev_printk(KERN_INFO, sdev, "get_req: blk_get_request failed");
		return NULL;
	}

	rq->cmd_len = COMMAND_SIZE(cmd);
	rq->cmd[0] = cmd;

	switch (cmd) {
	case MODE_SELECT:
		len = sizeof(short_trespass);
		rq->cmd[1] = 0x10;
		rq->cmd[4] = len;
		break;
	case MODE_SELECT_10:
		len = sizeof(long_trespass);
		rq->cmd[1] = 0x10;
		rq->cmd[8] = len;
		break;
	case INQUIRY:
		len = CLARIION_BUFFER_SIZE;
		rq->cmd[4] = len;
		memset(buffer, 0, len);
		break;
	default:
		BUG_ON(1);
		break;
	}

	rq->cmd_type = REQ_TYPE_BLOCK_PC;
	rq->cmd_flags |= REQ_FAILFAST_DEV | REQ_FAILFAST_TRANSPORT |
			 REQ_FAILFAST_DRIVER;
	rq->timeout = CLARIION_TIMEOUT;
	rq->retries = CLARIION_RETRIES;

	if (blk_rq_map_kern(rq->q, rq, buffer, len, GFP_NOIO)) {
		blk_put_request(rq);
		return NULL;
	}

	return rq;
}

static int send_inquiry_cmd(struct scsi_device *sdev, int page,
			    struct clariion_dh_data *csdev)
{
	struct request *rq = get_req(sdev, INQUIRY, csdev->buffer);
	int err;

	if (!rq)
		return SCSI_DH_RES_TEMP_UNAVAIL;

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

	rq->cmd[0] = INQUIRY;
	if (page != 0) {
		rq->cmd[1] = 1;
		rq->cmd[2] = page;
	}
	err = blk_execute_rq(sdev->request_queue, NULL, rq, 1);
	if (err == -EIO) {
		sdev_printk(KERN_INFO, sdev,
			    "%s: failed to send %s INQUIRY: %x\n",
			    CLARIION_NAME, page?"EVPD":"standard",
			    rq->errors);
		csdev->senselen = rq->sense_len;
		err = SCSI_DH_IO;
	}

	blk_put_request(rq);

	return err;
}

static int send_trespass_cmd(struct scsi_device *sdev,
			    struct clariion_dh_data *csdev)
{
	struct request *rq;
	unsigned char *page22;
	int err, len, cmd;

	if (csdev->flags & CLARIION_SHORT_TRESPASS) {
		page22 = short_trespass;
		if (!(csdev->flags & CLARIION_HONOR_RESERVATIONS))
			/* Set Honor Reservations bit */
			page22[6] |= 0x80;
		len = sizeof(short_trespass);
		cmd = MODE_SELECT;
	} else {
		page22 = long_trespass;
		if (!(csdev->flags & CLARIION_HONOR_RESERVATIONS))
			/* Set Honor Reservations bit */
			page22[10] |= 0x80;
		len = sizeof(long_trespass);
		cmd = MODE_SELECT_10;
	}
	BUG_ON((len > CLARIION_BUFFER_SIZE));
	memcpy(csdev->buffer, page22, len);

	rq = get_req(sdev, cmd, csdev->buffer);
	if (!rq)
		return SCSI_DH_RES_TEMP_UNAVAIL;

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

	err = blk_execute_rq(sdev->request_queue, NULL, rq, 1);
	if (err == -EIO) {
		if (rq->sense_len) {
			err = trespass_endio(sdev, csdev->sense);
		} else {
			sdev_printk(KERN_INFO, sdev,
				    "%s: failed to send MODE SELECT: %x\n",
				    CLARIION_NAME, rq->errors);
		}
	}

	blk_put_request(rq);

	return err;
}

static int clariion_check_sense(struct scsi_device *sdev,
				struct scsi_sense_hdr *sense_hdr)
{
	switch (sense_hdr->sense_key) {
	case NOT_READY:
		if (sense_hdr->asc == 0x04 && sense_hdr->ascq == 0x03)
			/*
			 * LUN Not Ready - Manual Intervention Required
			 * indicates this is a passive path.
			 *
			 * FIXME: However, if this is seen and EVPD C0
			 * indicates that this is due to a NDU in
			 * progress, we should set FAIL_PATH too.
			 * This indicates we might have to do a SCSI
			 * inquiry in the end_io path. Ugh.
			 *
			 * Can return FAILED only when we want the error
			 * recovery process to kick in.
			 */
			return SUCCESS;
		break;
	case ILLEGAL_REQUEST:
		if (sense_hdr->asc == 0x25 && sense_hdr->ascq == 0x01)
			/*
			 * An array based copy is in progress. Do not
			 * fail the path, do not bypass to another PG,
			 * do not retry. Fail the IO immediately.
			 * (Actually this is the same conclusion as in
			 * the default handler, but lets make sure.)
			 *
			 * Can return FAILED only when we want the error
			 * recovery process to kick in.
			 */
			return SUCCESS;
		break;
	case UNIT_ATTENTION:
		if (sense_hdr->asc == 0x29 && sense_hdr->ascq == 0x00)
			/*
			 * Unit Attention Code. This is the first IO
			 * to the new path, so just retry.
			 */
			return ADD_TO_MLQUEUE;
		break;
	}

	return SCSI_RETURN_NOT_HANDLED;
}

static int clariion_prep_fn(struct scsi_device *sdev, struct request *req)
{
	struct clariion_dh_data *h = get_clariion_data(sdev);
	int ret = BLKPREP_OK;

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

}

static int clariion_std_inquiry(struct scsi_device *sdev,
				struct clariion_dh_data *csdev)
{
	int err;
	char *sp_model;

	err = send_inquiry_cmd(sdev, 0, csdev);
	if (err != SCSI_DH_OK && csdev->senselen) {
		struct scsi_sense_hdr sshdr;

		if (scsi_normalize_sense(csdev->sense, SCSI_SENSE_BUFFERSIZE,
					 &sshdr)) {
			sdev_printk(KERN_ERR, sdev, "%s: INQUIRY sense code "
				    "%02x/%02x/%02x\n", CLARIION_NAME,
				    sshdr.sense_key, sshdr.asc, sshdr.ascq);
		}
		err = SCSI_DH_IO;
		goto out;
	}

	sp_model = parse_sp_model(sdev, csdev->buffer);
	if (!sp_model) {
		err = SCSI_DH_DEV_UNSUPP;
		goto out;
	}

	/*
	 * FC Series arrays do not support long trespass
	 */
	if (!strlen(sp_model) || !strncmp(sp_model, "FC",2))
		csdev->flags |= CLARIION_SHORT_TRESPASS;

	sdev_printk(KERN_INFO, sdev,
		    "%s: detected Clariion %s, flags %x\n",
		    CLARIION_NAME, sp_model, csdev->flags);
out:
	return err;
}

static int clariion_send_inquiry(struct scsi_device *sdev,
				 struct clariion_dh_data *csdev)
{
	int err, retry = CLARIION_RETRIES;

retry:
	err = send_inquiry_cmd(sdev, 0xC0, csdev);
	if (err != SCSI_DH_OK && csdev->senselen) {
		struct scsi_sense_hdr sshdr;

		err = scsi_normalize_sense(csdev->sense, SCSI_SENSE_BUFFERSIZE,
					   &sshdr);
		if (!err)
			return SCSI_DH_IO;

		err = clariion_check_sense(sdev, &sshdr);
		if (retry > 0 && err == ADD_TO_MLQUEUE) {
			retry--;
			goto retry;
		}
		sdev_printk(KERN_ERR, sdev, "%s: INQUIRY sense code "
			    "%02x/%02x/%02x\n", CLARIION_NAME,
			      sshdr.sense_key, sshdr.asc, sshdr.ascq);
		err = SCSI_DH_IO;
	} else {
		err = parse_sp_info_reply(sdev, csdev);
	}
	return err;
}

static int clariion_activate(struct scsi_device *sdev,
				activate_complete fn, void *data)
{
	struct clariion_dh_data *csdev = get_clariion_data(sdev);
	int result;

	result = clariion_send_inquiry(sdev, csdev);
	if (result != SCSI_DH_OK)
		goto done;

	if (csdev->lun_state == CLARIION_LUN_OWNED)
		goto done;

	result = send_trespass_cmd(sdev, csdev);
	if (result != SCSI_DH_OK)
		goto done;
	sdev_printk(KERN_INFO, sdev,"%s: %s trespass command sent\n",
		    CLARIION_NAME,
		    csdev->flags&CLARIION_SHORT_TRESPASS?"short":"long" );

	/* Update status */
	result = clariion_send_inquiry(sdev, csdev);
	if (result != SCSI_DH_OK)
		goto done;

done:
	sdev_printk(KERN_INFO, sdev,
		    "%s: at SP %c Port %d (%s, default SP %c)\n",
		    CLARIION_NAME, csdev->current_sp + 'A',
		    csdev->port, lun_state[csdev->lun_state],
		    csdev->default_sp + 'A');

	if (fn)
		fn(data, result);
	return 0;
}
/*
 * params - parameters in the following format
 *      "no_of_params\0param1\0param2\0param3\0...\0"
 *      for example, string for 2 parameters with value 10 and 21
 *      is specified as "2\010\021\0".
 */
static int clariion_set_params(struct scsi_device *sdev, const char *params)
{
	struct clariion_dh_data *csdev = get_clariion_data(sdev);
	unsigned int hr = 0, st = 0, argc;
	const char *p = params;
	int result = SCSI_DH_OK;

	if ((sscanf(params, "%u", &argc) != 1) || (argc != 2))
		return -EINVAL;

	while (*p++)
		;
	if ((sscanf(p, "%u", &st) != 1) || (st > 1))
		return -EINVAL;

	while (*p++)
		;
	if ((sscanf(p, "%u", &hr) != 1) || (hr > 1))
		return -EINVAL;

	if (st)
		csdev->flags |= CLARIION_SHORT_TRESPASS;
	else
		csdev->flags &= ~CLARIION_SHORT_TRESPASS;

	if (hr)
		csdev->flags |= CLARIION_HONOR_RESERVATIONS;
	else
		csdev->flags &= ~CLARIION_HONOR_RESERVATIONS;

	/*
	 * If this path is owned, we have to send a trespass command
	 * with the new parameters. If not, simply return. Next trespass
	 * command would use the parameters.
	 */
	if (csdev->lun_state != CLARIION_LUN_OWNED)
		goto done;

	csdev->lun_state = CLARIION_LUN_UNINITIALIZED;
	result = send_trespass_cmd(sdev, csdev);
	if (result != SCSI_DH_OK)
		goto done;

	/* Update status */
	result = clariion_send_inquiry(sdev, csdev);

done:
	return result;
}

static const struct scsi_dh_devlist clariion_dev_list[] = {
	{"DGC", "RAID"},
	{"DGC", "DISK"},
	{"DGC", "VRAID"},
	{NULL, NULL},
};

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

	if (scsi_device_tpgs(sdev))
		return false;

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

static int clariion_bus_attach(struct scsi_device *sdev);
static void clariion_bus_detach(struct scsi_device *sdev);

static struct scsi_device_handler clariion_dh = {
	.name		= CLARIION_NAME,
	.module		= THIS_MODULE,
	.devlist	= clariion_dev_list,
	.attach		= clariion_bus_attach,
	.detach		= clariion_bus_detach,
	.check_sense	= clariion_check_sense,
	.activate	= clariion_activate,
	.prep_fn	= clariion_prep_fn,
	.set_params	= clariion_set_params,
	.match		= clariion_match,
};

static int clariion_bus_attach(struct scsi_device *sdev)
{
	struct scsi_dh_data *scsi_dh_data;
	struct clariion_dh_data *h;
	unsigned long flags;
	int err;

	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",
			    CLARIION_NAME);
		return -ENOMEM;
	}

	scsi_dh_data->scsi_dh = &clariion_dh;
	h = (struct clariion_dh_data *) scsi_dh_data->buf;
	h->lun_state = CLARIION_LUN_UNINITIALIZED;
	h->default_sp = CLARIION_UNBOUND_LU;
	h->current_sp = CLARIION_UNBOUND_LU;

	err = clariion_std_inquiry(sdev, h);
	if (err != SCSI_DH_OK)
		goto failed;

	err = clariion_send_inquiry(sdev, h);
	if (err != SCSI_DH_OK)
		goto failed;

	if (!try_module_get(THIS_MODULE))
		goto failed;

	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_INFO, sdev,
		    "%s: connected to SP %c Port %d (%s, default SP %c)\n",
		    CLARIION_NAME, h->current_sp + 'A',
		    h->port, lun_state[h->lun_state],
		    h->default_sp + 'A');

	return 0;

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

static void clariion_bus_detach(struct scsi_device *sdev)
{
	struct scsi_dh_data *scsi_dh_data;
	unsigned long flags;

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

	sdev_printk(KERN_NOTICE, sdev, "%s: Detached\n",
		    CLARIION_NAME);

	kfree(scsi_dh_data);
	module_put(THIS_MODULE);
}

static int __init clariion_init(void)
{
	int r;

	r = scsi_register_device_handler(&clariion_dh);
	if (r != 0)
		printk(KERN_ERR "%s: Failed to register scsi device handler.",
			CLARIION_NAME);
	return r;
}

static void __exit clariion_exit(void)
{
	scsi_unregister_device_handler(&clariion_dh);
}

module_init(clariion_init);
module_exit(clariion_exit);

MODULE_DESCRIPTION("EMC CX/AX/FC-family driver");
MODULE_AUTHOR("Mike Christie <michaelc@cs.wisc.edu>, Chandra Seetharaman <sekharan@us.ibm.com>");
MODULE_LICENSE("GPL");