1 /*
2  * Engenio/LSI RDAC SCSI Device Handler
3  *
4  * Copyright (C) 2005 Mike Christie. All rights reserved.
5  * Copyright (C) Chandra Seetharaman, IBM Corp. 2007
6  *
7  * This program is free software; you can redistribute it and/or modify
8  * it under the terms of the GNU General Public License as published by
9  * the Free Software Foundation; either version 2 of the License, or
10  * (at your option) any later version.
11  *
12  * This program is distributed in the hope that it will be useful,
13  * but WITHOUT ANY WARRANTY; without even the implied warranty of
14  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
15  * GNU General Public License for more details.
16  *
17  * You should have received a copy of the GNU General Public License
18  * along with this program; if not, write to the Free Software
19  * Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
20  *
21  */
22 #include <scsi/scsi.h>
23 #include <scsi/scsi_eh.h>
24 #include <scsi/scsi_dh.h>
25 
26 #define RDAC_NAME "rdac"
27 #define RDAC_RETRY_COUNT 5
28 
29 /*
30  * LSI mode page stuff
31  *
32  * These struct definitions and the forming of the
33  * mode page were taken from the LSI RDAC 2.4 GPL'd
34  * driver, and then converted to Linux conventions.
35  */
36 #define RDAC_QUIESCENCE_TIME 20;
37 /*
38  * Page Codes
39  */
40 #define RDAC_PAGE_CODE_REDUNDANT_CONTROLLER 0x2c
41 
42 /*
43  * Controller modes definitions
44  */
45 #define RDAC_MODE_TRANSFER_SPECIFIED_LUNS	0x02
46 
47 /*
48  * RDAC Options field
49  */
50 #define RDAC_FORCED_QUIESENCE 0x02
51 
52 #define RDAC_TIMEOUT	(60 * HZ)
53 #define RDAC_RETRIES	3
54 
55 struct rdac_mode_6_hdr {
56 	u8	data_len;
57 	u8	medium_type;
58 	u8	device_params;
59 	u8	block_desc_len;
60 };
61 
62 struct rdac_mode_10_hdr {
63 	u16	data_len;
64 	u8	medium_type;
65 	u8	device_params;
66 	u16	reserved;
67 	u16	block_desc_len;
68 };
69 
70 struct rdac_mode_common {
71 	u8	controller_serial[16];
72 	u8	alt_controller_serial[16];
73 	u8	rdac_mode[2];
74 	u8	alt_rdac_mode[2];
75 	u8	quiescence_timeout;
76 	u8	rdac_options;
77 };
78 
79 struct rdac_pg_legacy {
80 	struct rdac_mode_6_hdr hdr;
81 	u8	page_code;
82 	u8	page_len;
83 	struct rdac_mode_common common;
84 #define MODE6_MAX_LUN	32
85 	u8	lun_table[MODE6_MAX_LUN];
86 	u8	reserved2[32];
87 	u8	reserved3;
88 	u8	reserved4;
89 };
90 
91 struct rdac_pg_expanded {
92 	struct rdac_mode_10_hdr hdr;
93 	u8	page_code;
94 	u8	subpage_code;
95 	u8	page_len[2];
96 	struct rdac_mode_common common;
97 	u8	lun_table[256];
98 	u8	reserved3;
99 	u8	reserved4;
100 };
101 
102 struct c9_inquiry {
103 	u8	peripheral_info;
104 	u8	page_code;	/* 0xC9 */
105 	u8	reserved1;
106 	u8	page_len;
107 	u8	page_id[4];	/* "vace" */
108 	u8	avte_cvp;
109 	u8	path_prio;
110 	u8	reserved2[38];
111 };
112 
113 #define SUBSYS_ID_LEN	16
114 #define SLOT_ID_LEN	2
115 #define ARRAY_LABEL_LEN	31
116 
117 struct c4_inquiry {
118 	u8	peripheral_info;
119 	u8	page_code;	/* 0xC4 */
120 	u8	reserved1;
121 	u8	page_len;
122 	u8	page_id[4];	/* "subs" */
123 	u8	subsys_id[SUBSYS_ID_LEN];
124 	u8	revision[4];
125 	u8	slot_id[SLOT_ID_LEN];
126 	u8	reserved[2];
127 };
128 
129 struct rdac_controller {
130 	u8			subsys_id[SUBSYS_ID_LEN];
131 	u8			slot_id[SLOT_ID_LEN];
132 	int			use_ms10;
133 	struct kref		kref;
134 	struct list_head	node; /* list of all controllers */
135 	union			{
136 		struct rdac_pg_legacy legacy;
137 		struct rdac_pg_expanded expanded;
138 	} mode_select;
139 	u8	index;
140 	u8	array_name[ARRAY_LABEL_LEN];
141 };
142 struct c8_inquiry {
143 	u8	peripheral_info;
144 	u8	page_code; /* 0xC8 */
145 	u8	reserved1;
146 	u8	page_len;
147 	u8	page_id[4]; /* "edid" */
148 	u8	reserved2[3];
149 	u8	vol_uniq_id_len;
150 	u8	vol_uniq_id[16];
151 	u8	vol_user_label_len;
152 	u8	vol_user_label[60];
153 	u8	array_uniq_id_len;
154 	u8	array_unique_id[16];
155 	u8	array_user_label_len;
156 	u8	array_user_label[60];
157 	u8	lun[8];
158 };
159 
160 struct c2_inquiry {
161 	u8	peripheral_info;
162 	u8	page_code;	/* 0xC2 */
163 	u8	reserved1;
164 	u8	page_len;
165 	u8	page_id[4];	/* "swr4" */
166 	u8	sw_version[3];
167 	u8	sw_date[3];
168 	u8	features_enabled;
169 	u8	max_lun_supported;
170 	u8	partitions[239]; /* Total allocation length should be 0xFF */
171 };
172 
173 struct rdac_dh_data {
174 	struct rdac_controller	*ctlr;
175 #define UNINITIALIZED_LUN	(1 << 8)
176 	unsigned		lun;
177 #define RDAC_STATE_ACTIVE	0
178 #define RDAC_STATE_PASSIVE	1
179 	unsigned char		state;
180 
181 #define RDAC_LUN_UNOWNED	0
182 #define RDAC_LUN_OWNED		1
183 #define RDAC_LUN_AVT		2
184 	char			lun_state;
185 	unsigned char		sense[SCSI_SENSE_BUFFERSIZE];
186 	union			{
187 		struct c2_inquiry c2;
188 		struct c4_inquiry c4;
189 		struct c8_inquiry c8;
190 		struct c9_inquiry c9;
191 	} inq;
192 };
193 
194 static const char *lun_state[] =
195 {
196 	"unowned",
197 	"owned",
198 	"owned (AVT mode)",
199 };
200 
201 static LIST_HEAD(ctlr_list);
202 static DEFINE_SPINLOCK(list_lock);
203 
204 /*
205  * module parameter to enable rdac debug logging.
206  * 2 bits for each type of logging, only two types defined for now
207  * Can be enhanced if required at later point
208  */
209 static int rdac_logging = 1;
210 module_param(rdac_logging, int, S_IRUGO|S_IWUSR);
211 MODULE_PARM_DESC(rdac_logging, "A bit mask of rdac logging levels, "
212 		"Default is 1 - failover logging enabled, "
213 		"set it to 0xF to enable all the logs");
214 
215 #define RDAC_LOG_FAILOVER	0
216 #define RDAC_LOG_SENSE		2
217 
218 #define RDAC_LOG_BITS		2
219 
220 #define RDAC_LOG_LEVEL(SHIFT)  \
221 	((rdac_logging >> (SHIFT)) & ((1 << (RDAC_LOG_BITS)) - 1))
222 
223 #define RDAC_LOG(SHIFT, sdev, f, arg...) \
224 do { \
225 	if (unlikely(RDAC_LOG_LEVEL(SHIFT))) \
226 		sdev_printk(KERN_INFO, sdev, RDAC_NAME ": " f "\n", ## arg); \
227 } while (0);
228 
229 static inline struct rdac_dh_data *get_rdac_data(struct scsi_device *sdev)
230 {
231 	struct scsi_dh_data *scsi_dh_data = sdev->scsi_dh_data;
232 	BUG_ON(scsi_dh_data == NULL);
233 	return ((struct rdac_dh_data *) scsi_dh_data->buf);
234 }
235 
236 static struct request *get_rdac_req(struct scsi_device *sdev,
237 			void *buffer, unsigned buflen, int rw)
238 {
239 	struct request *rq;
240 	struct request_queue *q = sdev->request_queue;
241 
242 	rq = blk_get_request(q, rw, GFP_NOIO);
243 
244 	if (!rq) {
245 		sdev_printk(KERN_INFO, sdev,
246 				"get_rdac_req: blk_get_request failed.\n");
247 		return NULL;
248 	}
249 
250 	if (buflen && blk_rq_map_kern(q, rq, buffer, buflen, GFP_NOIO)) {
251 		blk_put_request(rq);
252 		sdev_printk(KERN_INFO, sdev,
253 				"get_rdac_req: blk_rq_map_kern failed.\n");
254 		return NULL;
255 	}
256 
257 	rq->cmd_type = REQ_TYPE_BLOCK_PC;
258 	rq->cmd_flags |= REQ_FAILFAST_DEV | REQ_FAILFAST_TRANSPORT |
259 			 REQ_FAILFAST_DRIVER;
260 	rq->retries = RDAC_RETRIES;
261 	rq->timeout = RDAC_TIMEOUT;
262 
263 	return rq;
264 }
265 
266 static struct request *rdac_failover_get(struct scsi_device *sdev,
267 					 struct rdac_dh_data *h)
268 {
269 	struct request *rq;
270 	struct rdac_mode_common *common;
271 	unsigned data_size;
272 
273 	if (h->ctlr->use_ms10) {
274 		struct rdac_pg_expanded *rdac_pg;
275 
276 		data_size = sizeof(struct rdac_pg_expanded);
277 		rdac_pg = &h->ctlr->mode_select.expanded;
278 		memset(rdac_pg, 0, data_size);
279 		common = &rdac_pg->common;
280 		rdac_pg->page_code = RDAC_PAGE_CODE_REDUNDANT_CONTROLLER + 0x40;
281 		rdac_pg->subpage_code = 0x1;
282 		rdac_pg->page_len[0] = 0x01;
283 		rdac_pg->page_len[1] = 0x28;
284 		rdac_pg->lun_table[h->lun] = 0x81;
285 	} else {
286 		struct rdac_pg_legacy *rdac_pg;
287 
288 		data_size = sizeof(struct rdac_pg_legacy);
289 		rdac_pg = &h->ctlr->mode_select.legacy;
290 		memset(rdac_pg, 0, data_size);
291 		common = &rdac_pg->common;
292 		rdac_pg->page_code = RDAC_PAGE_CODE_REDUNDANT_CONTROLLER;
293 		rdac_pg->page_len = 0x68;
294 		rdac_pg->lun_table[h->lun] = 0x81;
295 	}
296 	common->rdac_mode[1] = RDAC_MODE_TRANSFER_SPECIFIED_LUNS;
297 	common->quiescence_timeout = RDAC_QUIESCENCE_TIME;
298 	common->rdac_options = RDAC_FORCED_QUIESENCE;
299 
300 	/* get request for block layer packet command */
301 	rq = get_rdac_req(sdev, &h->ctlr->mode_select, data_size, WRITE);
302 	if (!rq)
303 		return NULL;
304 
305 	/* Prepare the command. */
306 	if (h->ctlr->use_ms10) {
307 		rq->cmd[0] = MODE_SELECT_10;
308 		rq->cmd[7] = data_size >> 8;
309 		rq->cmd[8] = data_size & 0xff;
310 	} else {
311 		rq->cmd[0] = MODE_SELECT;
312 		rq->cmd[4] = data_size;
313 	}
314 	rq->cmd_len = COMMAND_SIZE(rq->cmd[0]);
315 
316 	rq->sense = h->sense;
317 	memset(rq->sense, 0, SCSI_SENSE_BUFFERSIZE);
318 	rq->sense_len = 0;
319 
320 	return rq;
321 }
322 
323 static void release_controller(struct kref *kref)
324 {
325 	struct rdac_controller *ctlr;
326 	ctlr = container_of(kref, struct rdac_controller, kref);
327 
328 	spin_lock(&list_lock);
329 	list_del(&ctlr->node);
330 	spin_unlock(&list_lock);
331 	kfree(ctlr);
332 }
333 
334 static struct rdac_controller *get_controller(u8 *subsys_id, u8 *slot_id,
335 						char *array_name)
336 {
337 	struct rdac_controller *ctlr, *tmp;
338 
339 	spin_lock(&list_lock);
340 
341 	list_for_each_entry(tmp, &ctlr_list, node) {
342 		if ((memcmp(tmp->subsys_id, subsys_id, SUBSYS_ID_LEN) == 0) &&
343 			  (memcmp(tmp->slot_id, slot_id, SLOT_ID_LEN) == 0)) {
344 			kref_get(&tmp->kref);
345 			spin_unlock(&list_lock);
346 			return tmp;
347 		}
348 	}
349 	ctlr = kmalloc(sizeof(*ctlr), GFP_ATOMIC);
350 	if (!ctlr)
351 		goto done;
352 
353 	/* initialize fields of controller */
354 	memcpy(ctlr->subsys_id, subsys_id, SUBSYS_ID_LEN);
355 	memcpy(ctlr->slot_id, slot_id, SLOT_ID_LEN);
356 	memcpy(ctlr->array_name, array_name, ARRAY_LABEL_LEN);
357 
358 	/* update the controller index */
359 	if (slot_id[1] == 0x31)
360 		ctlr->index = 0;
361 	else
362 		ctlr->index = 1;
363 
364 	kref_init(&ctlr->kref);
365 	ctlr->use_ms10 = -1;
366 	list_add(&ctlr->node, &ctlr_list);
367 done:
368 	spin_unlock(&list_lock);
369 	return ctlr;
370 }
371 
372 static int submit_inquiry(struct scsi_device *sdev, int page_code,
373 			  unsigned int len, struct rdac_dh_data *h)
374 {
375 	struct request *rq;
376 	struct request_queue *q = sdev->request_queue;
377 	int err = SCSI_DH_RES_TEMP_UNAVAIL;
378 
379 	rq = get_rdac_req(sdev, &h->inq, len, READ);
380 	if (!rq)
381 		goto done;
382 
383 	/* Prepare the command. */
384 	rq->cmd[0] = INQUIRY;
385 	rq->cmd[1] = 1;
386 	rq->cmd[2] = page_code;
387 	rq->cmd[4] = len;
388 	rq->cmd_len = COMMAND_SIZE(INQUIRY);
389 
390 	rq->sense = h->sense;
391 	memset(rq->sense, 0, SCSI_SENSE_BUFFERSIZE);
392 	rq->sense_len = 0;
393 
394 	err = blk_execute_rq(q, NULL, rq, 1);
395 	if (err == -EIO)
396 		err = SCSI_DH_IO;
397 
398 	blk_put_request(rq);
399 done:
400 	return err;
401 }
402 
403 static int get_lun_info(struct scsi_device *sdev, struct rdac_dh_data *h,
404 			char *array_name)
405 {
406 	int err, i;
407 	struct c8_inquiry *inqp;
408 
409 	err = submit_inquiry(sdev, 0xC8, sizeof(struct c8_inquiry), h);
410 	if (err == SCSI_DH_OK) {
411 		inqp = &h->inq.c8;
412 		if (inqp->page_code != 0xc8)
413 			return SCSI_DH_NOSYS;
414 		if (inqp->page_id[0] != 'e' || inqp->page_id[1] != 'd' ||
415 		    inqp->page_id[2] != 'i' || inqp->page_id[3] != 'd')
416 			return SCSI_DH_NOSYS;
417 		h->lun = inqp->lun[7]; /* Uses only the last byte */
418 
419 		for(i=0; i<ARRAY_LABEL_LEN-1; ++i)
420 			*(array_name+i) = inqp->array_user_label[(2*i)+1];
421 
422 		*(array_name+ARRAY_LABEL_LEN-1) = '\0';
423 	}
424 	return err;
425 }
426 
427 static int check_ownership(struct scsi_device *sdev, struct rdac_dh_data *h)
428 {
429 	int err;
430 	struct c9_inquiry *inqp;
431 
432 	h->lun_state = RDAC_LUN_UNOWNED;
433 	h->state = RDAC_STATE_ACTIVE;
434 	err = submit_inquiry(sdev, 0xC9, sizeof(struct c9_inquiry), h);
435 	if (err == SCSI_DH_OK) {
436 		inqp = &h->inq.c9;
437 		if ((inqp->avte_cvp >> 7) == 0x1) {
438 			/* LUN in AVT mode */
439 			sdev_printk(KERN_NOTICE, sdev,
440 				    "%s: AVT mode detected\n",
441 				    RDAC_NAME);
442 			h->lun_state = RDAC_LUN_AVT;
443 		} else if ((inqp->avte_cvp & 0x1) != 0) {
444 			/* LUN was owned by the controller */
445 			h->lun_state = RDAC_LUN_OWNED;
446 		}
447 	}
448 
449 	if (h->lun_state == RDAC_LUN_UNOWNED)
450 		h->state = RDAC_STATE_PASSIVE;
451 
452 	return err;
453 }
454 
455 static int initialize_controller(struct scsi_device *sdev,
456 				 struct rdac_dh_data *h, char *array_name)
457 {
458 	int err;
459 	struct c4_inquiry *inqp;
460 
461 	err = submit_inquiry(sdev, 0xC4, sizeof(struct c4_inquiry), h);
462 	if (err == SCSI_DH_OK) {
463 		inqp = &h->inq.c4;
464 		h->ctlr = get_controller(inqp->subsys_id, inqp->slot_id,
465 					array_name);
466 		if (!h->ctlr)
467 			err = SCSI_DH_RES_TEMP_UNAVAIL;
468 	}
469 	return err;
470 }
471 
472 static int set_mode_select(struct scsi_device *sdev, struct rdac_dh_data *h)
473 {
474 	int err;
475 	struct c2_inquiry *inqp;
476 
477 	err = submit_inquiry(sdev, 0xC2, sizeof(struct c2_inquiry), h);
478 	if (err == SCSI_DH_OK) {
479 		inqp = &h->inq.c2;
480 		/*
481 		 * If more than MODE6_MAX_LUN luns are supported, use
482 		 * mode select 10
483 		 */
484 		if (inqp->max_lun_supported >= MODE6_MAX_LUN)
485 			h->ctlr->use_ms10 = 1;
486 		else
487 			h->ctlr->use_ms10 = 0;
488 	}
489 	return err;
490 }
491 
492 static int mode_select_handle_sense(struct scsi_device *sdev,
493 				    unsigned char *sensebuf)
494 {
495 	struct scsi_sense_hdr sense_hdr;
496 	int err = SCSI_DH_IO, ret;
497 	struct rdac_dh_data *h = get_rdac_data(sdev);
498 
499 	ret = scsi_normalize_sense(sensebuf, SCSI_SENSE_BUFFERSIZE, &sense_hdr);
500 	if (!ret)
501 		goto done;
502 
503 	err = SCSI_DH_OK;
504 
505 	switch (sense_hdr.sense_key) {
506 	case NO_SENSE:
507 	case ABORTED_COMMAND:
508 	case UNIT_ATTENTION:
509 		err = SCSI_DH_RETRY;
510 		break;
511 	case NOT_READY:
512 		if (sense_hdr.asc == 0x04 && sense_hdr.ascq == 0x01)
513 			/* LUN Not Ready and is in the Process of Becoming
514 			 * Ready
515 			 */
516 			err = SCSI_DH_RETRY;
517 		break;
518 	case ILLEGAL_REQUEST:
519 		if (sense_hdr.asc == 0x91 && sense_hdr.ascq == 0x36)
520 			/*
521 			 * Command Lock contention
522 			 */
523 			err = SCSI_DH_RETRY;
524 		break;
525 	default:
526 		break;
527 	}
528 
529 	RDAC_LOG(RDAC_LOG_FAILOVER, sdev, "array %s, ctlr %d, "
530 		"MODE_SELECT returned with sense %02x/%02x/%02x",
531 		(char *) h->ctlr->array_name, h->ctlr->index,
532 		sense_hdr.sense_key, sense_hdr.asc, sense_hdr.ascq);
533 
534 done:
535 	return err;
536 }
537 
538 static int send_mode_select(struct scsi_device *sdev, struct rdac_dh_data *h)
539 {
540 	struct request *rq;
541 	struct request_queue *q = sdev->request_queue;
542 	int err, retry_cnt = RDAC_RETRY_COUNT;
543 
544 retry:
545 	err = SCSI_DH_RES_TEMP_UNAVAIL;
546 	rq = rdac_failover_get(sdev, h);
547 	if (!rq)
548 		goto done;
549 
550 	RDAC_LOG(RDAC_LOG_FAILOVER, sdev, "array %s, ctlr %d, "
551 		"%s MODE_SELECT command",
552 		(char *) h->ctlr->array_name, h->ctlr->index,
553 		(retry_cnt == RDAC_RETRY_COUNT) ? "queueing" : "retrying");
554 
555 	err = blk_execute_rq(q, NULL, rq, 1);
556 	blk_put_request(rq);
557 	if (err != SCSI_DH_OK) {
558 		err = mode_select_handle_sense(sdev, h->sense);
559 		if (err == SCSI_DH_RETRY && retry_cnt--)
560 			goto retry;
561 	}
562 	if (err == SCSI_DH_OK) {
563 		h->state = RDAC_STATE_ACTIVE;
564 		RDAC_LOG(RDAC_LOG_FAILOVER, sdev, "array %s, ctlr %d, "
565 				"MODE_SELECT completed",
566 				(char *) h->ctlr->array_name, h->ctlr->index);
567 	}
568 
569 done:
570 	return err;
571 }
572 
573 static int rdac_activate(struct scsi_device *sdev)
574 {
575 	struct rdac_dh_data *h = get_rdac_data(sdev);
576 	int err = SCSI_DH_OK;
577 
578 	err = check_ownership(sdev, h);
579 	if (err != SCSI_DH_OK)
580 		goto done;
581 
582 	if (h->lun_state == RDAC_LUN_UNOWNED)
583 		err = send_mode_select(sdev, h);
584 done:
585 	return err;
586 }
587 
588 static int rdac_prep_fn(struct scsi_device *sdev, struct request *req)
589 {
590 	struct rdac_dh_data *h = get_rdac_data(sdev);
591 	int ret = BLKPREP_OK;
592 
593 	if (h->state != RDAC_STATE_ACTIVE) {
594 		ret = BLKPREP_KILL;
595 		req->cmd_flags |= REQ_QUIET;
596 	}
597 	return ret;
598 
599 }
600 
601 static int rdac_check_sense(struct scsi_device *sdev,
602 				struct scsi_sense_hdr *sense_hdr)
603 {
604 	struct rdac_dh_data *h = get_rdac_data(sdev);
605 
606 	RDAC_LOG(RDAC_LOG_SENSE, sdev, "array %s, ctlr %d, "
607 			"I/O returned with sense %02x/%02x/%02x",
608 			(char *) h->ctlr->array_name, h->ctlr->index,
609 			sense_hdr->sense_key, sense_hdr->asc, sense_hdr->ascq);
610 
611 	switch (sense_hdr->sense_key) {
612 	case NOT_READY:
613 		if (sense_hdr->asc == 0x04 && sense_hdr->ascq == 0x01)
614 			/* LUN Not Ready - Logical Unit Not Ready and is in
615 			* the process of becoming ready
616 			* Just retry.
617 			*/
618 			return ADD_TO_MLQUEUE;
619 		if (sense_hdr->asc == 0x04 && sense_hdr->ascq == 0x81)
620 			/* LUN Not Ready - Storage firmware incompatible
621 			 * Manual code synchonisation required.
622 			 *
623 			 * Nothing we can do here. Try to bypass the path.
624 			 */
625 			return SUCCESS;
626 		if (sense_hdr->asc == 0x04 && sense_hdr->ascq == 0xA1)
627 			/* LUN Not Ready - Quiescense in progress
628 			 *
629 			 * Just retry and wait.
630 			 */
631 			return ADD_TO_MLQUEUE;
632 		if (sense_hdr->asc == 0xA1  && sense_hdr->ascq == 0x02)
633 			/* LUN Not Ready - Quiescense in progress
634 			 * or has been achieved
635 			 * Just retry.
636 			 */
637 			return ADD_TO_MLQUEUE;
638 		break;
639 	case ILLEGAL_REQUEST:
640 		if (sense_hdr->asc == 0x94 && sense_hdr->ascq == 0x01) {
641 			/* Invalid Request - Current Logical Unit Ownership.
642 			 * Controller is not the current owner of the LUN,
643 			 * Fail the path, so that the other path be used.
644 			 */
645 			h->state = RDAC_STATE_PASSIVE;
646 			return SUCCESS;
647 		}
648 		break;
649 	case UNIT_ATTENTION:
650 		if (sense_hdr->asc == 0x29 && sense_hdr->ascq == 0x00)
651 			/*
652 			 * Power On, Reset, or Bus Device Reset, just retry.
653 			 */
654 			return ADD_TO_MLQUEUE;
655 		if (sense_hdr->asc == 0x8b && sense_hdr->ascq == 0x02)
656 			/*
657 			 * Quiescence in progress , just retry.
658 			 */
659 			return ADD_TO_MLQUEUE;
660 		break;
661 	}
662 	/* success just means we do not care what scsi-ml does */
663 	return SCSI_RETURN_NOT_HANDLED;
664 }
665 
666 static const struct scsi_dh_devlist rdac_dev_list[] = {
667 	{"IBM", "1722"},
668 	{"IBM", "1724"},
669 	{"IBM", "1726"},
670 	{"IBM", "1742"},
671 	{"IBM", "1814"},
672 	{"IBM", "1815"},
673 	{"IBM", "1818"},
674 	{"IBM", "3526"},
675 	{"SGI", "TP9400"},
676 	{"SGI", "TP9500"},
677 	{"SGI", "IS"},
678 	{"STK", "OPENstorage D280"},
679 	{"SUN", "CSM200_R"},
680 	{"SUN", "LCSM100_I"},
681 	{"SUN", "LCSM100_S"},
682 	{"SUN", "LCSM100_E"},
683 	{"SUN", "LCSM100_F"},
684 	{"DELL", "MD3000"},
685 	{"DELL", "MD3000i"},
686 	{"DELL", "MD32xx"},
687 	{"DELL", "MD32xxi"},
688 	{"LSI", "INF-01-00"},
689 	{"ENGENIO", "INF-01-00"},
690 	{"STK", "FLEXLINE 380"},
691 	{"SUN", "CSM100_R_FC"},
692 	{NULL, NULL},
693 };
694 
695 static int rdac_bus_attach(struct scsi_device *sdev);
696 static void rdac_bus_detach(struct scsi_device *sdev);
697 
698 static struct scsi_device_handler rdac_dh = {
699 	.name = RDAC_NAME,
700 	.module = THIS_MODULE,
701 	.devlist = rdac_dev_list,
702 	.prep_fn = rdac_prep_fn,
703 	.check_sense = rdac_check_sense,
704 	.attach = rdac_bus_attach,
705 	.detach = rdac_bus_detach,
706 	.activate = rdac_activate,
707 };
708 
709 static int rdac_bus_attach(struct scsi_device *sdev)
710 {
711 	struct scsi_dh_data *scsi_dh_data;
712 	struct rdac_dh_data *h;
713 	unsigned long flags;
714 	int err;
715 	char array_name[ARRAY_LABEL_LEN];
716 
717 	scsi_dh_data = kzalloc(sizeof(struct scsi_device_handler *)
718 			       + sizeof(*h) , GFP_KERNEL);
719 	if (!scsi_dh_data) {
720 		sdev_printk(KERN_ERR, sdev, "%s: Attach failed\n",
721 			    RDAC_NAME);
722 		return 0;
723 	}
724 
725 	scsi_dh_data->scsi_dh = &rdac_dh;
726 	h = (struct rdac_dh_data *) scsi_dh_data->buf;
727 	h->lun = UNINITIALIZED_LUN;
728 	h->state = RDAC_STATE_ACTIVE;
729 
730 	err = get_lun_info(sdev, h, array_name);
731 	if (err != SCSI_DH_OK)
732 		goto failed;
733 
734 	err = initialize_controller(sdev, h, array_name);
735 	if (err != SCSI_DH_OK)
736 		goto failed;
737 
738 	err = check_ownership(sdev, h);
739 	if (err != SCSI_DH_OK)
740 		goto clean_ctlr;
741 
742 	err = set_mode_select(sdev, h);
743 	if (err != SCSI_DH_OK)
744 		goto clean_ctlr;
745 
746 	if (!try_module_get(THIS_MODULE))
747 		goto clean_ctlr;
748 
749 	spin_lock_irqsave(sdev->request_queue->queue_lock, flags);
750 	sdev->scsi_dh_data = scsi_dh_data;
751 	spin_unlock_irqrestore(sdev->request_queue->queue_lock, flags);
752 
753 	sdev_printk(KERN_NOTICE, sdev,
754 		    "%s: LUN %d (%s)\n",
755 		    RDAC_NAME, h->lun, lun_state[(int)h->lun_state]);
756 
757 	return 0;
758 
759 clean_ctlr:
760 	kref_put(&h->ctlr->kref, release_controller);
761 
762 failed:
763 	kfree(scsi_dh_data);
764 	sdev_printk(KERN_ERR, sdev, "%s: not attached\n",
765 		    RDAC_NAME);
766 	return -EINVAL;
767 }
768 
769 static void rdac_bus_detach( struct scsi_device *sdev )
770 {
771 	struct scsi_dh_data *scsi_dh_data;
772 	struct rdac_dh_data *h;
773 	unsigned long flags;
774 
775 	spin_lock_irqsave(sdev->request_queue->queue_lock, flags);
776 	scsi_dh_data = sdev->scsi_dh_data;
777 	sdev->scsi_dh_data = NULL;
778 	spin_unlock_irqrestore(sdev->request_queue->queue_lock, flags);
779 
780 	h = (struct rdac_dh_data *) scsi_dh_data->buf;
781 	if (h->ctlr)
782 		kref_put(&h->ctlr->kref, release_controller);
783 	kfree(scsi_dh_data);
784 	module_put(THIS_MODULE);
785 	sdev_printk(KERN_NOTICE, sdev, "%s: Detached\n", RDAC_NAME);
786 }
787 
788 
789 
790 static int __init rdac_init(void)
791 {
792 	int r;
793 
794 	r = scsi_register_device_handler(&rdac_dh);
795 	if (r != 0)
796 		printk(KERN_ERR "Failed to register scsi device handler.");
797 	return r;
798 }
799 
800 static void __exit rdac_exit(void)
801 {
802 	scsi_unregister_device_handler(&rdac_dh);
803 }
804 
805 module_init(rdac_init);
806 module_exit(rdac_exit);
807 
808 MODULE_DESCRIPTION("Multipath LSI/Engenio RDAC driver");
809 MODULE_AUTHOR("Mike Christie, Chandra Seetharaman");
810 MODULE_LICENSE("GPL");
811