1 /*
2  * LSI/Engenio/NetApp E-Series 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 #include <linux/workqueue.h>
26 #include <linux/slab.h>
27 #include <linux/module.h>
28 
29 #define RDAC_NAME "rdac"
30 #define RDAC_RETRY_COUNT 5
31 
32 /*
33  * LSI mode page stuff
34  *
35  * These struct definitions and the forming of the
36  * mode page were taken from the LSI RDAC 2.4 GPL'd
37  * driver, and then converted to Linux conventions.
38  */
39 #define RDAC_QUIESCENCE_TIME 20
40 /*
41  * Page Codes
42  */
43 #define RDAC_PAGE_CODE_REDUNDANT_CONTROLLER 0x2c
44 
45 /*
46  * Controller modes definitions
47  */
48 #define RDAC_MODE_TRANSFER_SPECIFIED_LUNS	0x02
49 
50 /*
51  * RDAC Options field
52  */
53 #define RDAC_FORCED_QUIESENCE 0x02
54 
55 #define RDAC_TIMEOUT	(60 * HZ)
56 #define RDAC_RETRIES	3
57 
58 struct rdac_mode_6_hdr {
59 	u8	data_len;
60 	u8	medium_type;
61 	u8	device_params;
62 	u8	block_desc_len;
63 };
64 
65 struct rdac_mode_10_hdr {
66 	u16	data_len;
67 	u8	medium_type;
68 	u8	device_params;
69 	u16	reserved;
70 	u16	block_desc_len;
71 };
72 
73 struct rdac_mode_common {
74 	u8	controller_serial[16];
75 	u8	alt_controller_serial[16];
76 	u8	rdac_mode[2];
77 	u8	alt_rdac_mode[2];
78 	u8	quiescence_timeout;
79 	u8	rdac_options;
80 };
81 
82 struct rdac_pg_legacy {
83 	struct rdac_mode_6_hdr hdr;
84 	u8	page_code;
85 	u8	page_len;
86 	struct rdac_mode_common common;
87 #define MODE6_MAX_LUN	32
88 	u8	lun_table[MODE6_MAX_LUN];
89 	u8	reserved2[32];
90 	u8	reserved3;
91 	u8	reserved4;
92 };
93 
94 struct rdac_pg_expanded {
95 	struct rdac_mode_10_hdr hdr;
96 	u8	page_code;
97 	u8	subpage_code;
98 	u8	page_len[2];
99 	struct rdac_mode_common common;
100 	u8	lun_table[256];
101 	u8	reserved3;
102 	u8	reserved4;
103 };
104 
105 struct c9_inquiry {
106 	u8	peripheral_info;
107 	u8	page_code;	/* 0xC9 */
108 	u8	reserved1;
109 	u8	page_len;
110 	u8	page_id[4];	/* "vace" */
111 	u8	avte_cvp;
112 	u8	path_prio;
113 	u8	reserved2[38];
114 };
115 
116 #define SUBSYS_ID_LEN	16
117 #define SLOT_ID_LEN	2
118 #define ARRAY_LABEL_LEN	31
119 
120 struct c4_inquiry {
121 	u8	peripheral_info;
122 	u8	page_code;	/* 0xC4 */
123 	u8	reserved1;
124 	u8	page_len;
125 	u8	page_id[4];	/* "subs" */
126 	u8	subsys_id[SUBSYS_ID_LEN];
127 	u8	revision[4];
128 	u8	slot_id[SLOT_ID_LEN];
129 	u8	reserved[2];
130 };
131 
132 #define UNIQUE_ID_LEN 16
133 struct c8_inquiry {
134 	u8	peripheral_info;
135 	u8	page_code; /* 0xC8 */
136 	u8	reserved1;
137 	u8	page_len;
138 	u8	page_id[4]; /* "edid" */
139 	u8	reserved2[3];
140 	u8	vol_uniq_id_len;
141 	u8	vol_uniq_id[16];
142 	u8	vol_user_label_len;
143 	u8	vol_user_label[60];
144 	u8	array_uniq_id_len;
145 	u8	array_unique_id[UNIQUE_ID_LEN];
146 	u8	array_user_label_len;
147 	u8	array_user_label[60];
148 	u8	lun[8];
149 };
150 
151 struct rdac_controller {
152 	u8			array_id[UNIQUE_ID_LEN];
153 	int			use_ms10;
154 	struct kref		kref;
155 	struct list_head	node; /* list of all controllers */
156 	union			{
157 		struct rdac_pg_legacy legacy;
158 		struct rdac_pg_expanded expanded;
159 	} mode_select;
160 	u8	index;
161 	u8	array_name[ARRAY_LABEL_LEN];
162 	struct Scsi_Host	*host;
163 	spinlock_t		ms_lock;
164 	int			ms_queued;
165 	struct work_struct	ms_work;
166 	struct scsi_device	*ms_sdev;
167 	struct list_head	ms_head;
168 	struct list_head	dh_list;
169 };
170 
171 struct c2_inquiry {
172 	u8	peripheral_info;
173 	u8	page_code;	/* 0xC2 */
174 	u8	reserved1;
175 	u8	page_len;
176 	u8	page_id[4];	/* "swr4" */
177 	u8	sw_version[3];
178 	u8	sw_date[3];
179 	u8	features_enabled;
180 	u8	max_lun_supported;
181 	u8	partitions[239]; /* Total allocation length should be 0xFF */
182 };
183 
184 struct rdac_dh_data {
185 	struct list_head	node;
186 	struct rdac_controller	*ctlr;
187 	struct scsi_device	*sdev;
188 #define UNINITIALIZED_LUN	(1 << 8)
189 	unsigned		lun;
190 
191 #define RDAC_MODE		0
192 #define RDAC_MODE_AVT		1
193 #define RDAC_MODE_IOSHIP	2
194 	unsigned char		mode;
195 
196 #define RDAC_STATE_ACTIVE	0
197 #define RDAC_STATE_PASSIVE	1
198 	unsigned char		state;
199 
200 #define RDAC_LUN_UNOWNED	0
201 #define RDAC_LUN_OWNED		1
202 	char			lun_state;
203 
204 #define RDAC_PREFERRED		0
205 #define RDAC_NON_PREFERRED	1
206 	char			preferred;
207 
208 	unsigned char		sense[SCSI_SENSE_BUFFERSIZE];
209 	union			{
210 		struct c2_inquiry c2;
211 		struct c4_inquiry c4;
212 		struct c8_inquiry c8;
213 		struct c9_inquiry c9;
214 	} inq;
215 };
216 
217 static const char *mode[] = {
218 	"RDAC",
219 	"AVT",
220 	"IOSHIP",
221 };
222 static const char *lun_state[] =
223 {
224 	"unowned",
225 	"owned",
226 };
227 
228 struct rdac_queue_data {
229 	struct list_head	entry;
230 	struct rdac_dh_data	*h;
231 	activate_complete	callback_fn;
232 	void			*callback_data;
233 };
234 
235 static LIST_HEAD(ctlr_list);
236 static DEFINE_SPINLOCK(list_lock);
237 static struct workqueue_struct *kmpath_rdacd;
238 static void send_mode_select(struct work_struct *work);
239 
240 /*
241  * module parameter to enable rdac debug logging.
242  * 2 bits for each type of logging, only two types defined for now
243  * Can be enhanced if required at later point
244  */
245 static int rdac_logging = 1;
246 module_param(rdac_logging, int, S_IRUGO|S_IWUSR);
247 MODULE_PARM_DESC(rdac_logging, "A bit mask of rdac logging levels, "
248 		"Default is 1 - failover logging enabled, "
249 		"set it to 0xF to enable all the logs");
250 
251 #define RDAC_LOG_FAILOVER	0
252 #define RDAC_LOG_SENSE		2
253 
254 #define RDAC_LOG_BITS		2
255 
256 #define RDAC_LOG_LEVEL(SHIFT)  \
257 	((rdac_logging >> (SHIFT)) & ((1 << (RDAC_LOG_BITS)) - 1))
258 
259 #define RDAC_LOG(SHIFT, sdev, f, arg...) \
260 do { \
261 	if (unlikely(RDAC_LOG_LEVEL(SHIFT))) \
262 		sdev_printk(KERN_INFO, sdev, RDAC_NAME ": " f "\n", ## arg); \
263 } while (0);
264 
265 static struct request *get_rdac_req(struct scsi_device *sdev,
266 			void *buffer, unsigned buflen, int rw)
267 {
268 	struct request *rq;
269 	struct request_queue *q = sdev->request_queue;
270 
271 	rq = blk_get_request(q, rw, GFP_NOIO);
272 
273 	if (IS_ERR(rq)) {
274 		sdev_printk(KERN_INFO, sdev,
275 				"get_rdac_req: blk_get_request failed.\n");
276 		return NULL;
277 	}
278 	blk_rq_set_block_pc(rq);
279 
280 	if (buflen && blk_rq_map_kern(q, rq, buffer, buflen, GFP_NOIO)) {
281 		blk_put_request(rq);
282 		sdev_printk(KERN_INFO, sdev,
283 				"get_rdac_req: blk_rq_map_kern failed.\n");
284 		return NULL;
285 	}
286 
287 	rq->cmd_flags |= REQ_FAILFAST_DEV | REQ_FAILFAST_TRANSPORT |
288 			 REQ_FAILFAST_DRIVER;
289 	rq->retries = RDAC_RETRIES;
290 	rq->timeout = RDAC_TIMEOUT;
291 
292 	return rq;
293 }
294 
295 static struct request *rdac_failover_get(struct scsi_device *sdev,
296 			struct rdac_dh_data *h, struct list_head *list)
297 {
298 	struct request *rq;
299 	struct rdac_mode_common *common;
300 	unsigned data_size;
301 	struct rdac_queue_data *qdata;
302 	u8 *lun_table;
303 
304 	if (h->ctlr->use_ms10) {
305 		struct rdac_pg_expanded *rdac_pg;
306 
307 		data_size = sizeof(struct rdac_pg_expanded);
308 		rdac_pg = &h->ctlr->mode_select.expanded;
309 		memset(rdac_pg, 0, data_size);
310 		common = &rdac_pg->common;
311 		rdac_pg->page_code = RDAC_PAGE_CODE_REDUNDANT_CONTROLLER + 0x40;
312 		rdac_pg->subpage_code = 0x1;
313 		rdac_pg->page_len[0] = 0x01;
314 		rdac_pg->page_len[1] = 0x28;
315 		lun_table = rdac_pg->lun_table;
316 	} else {
317 		struct rdac_pg_legacy *rdac_pg;
318 
319 		data_size = sizeof(struct rdac_pg_legacy);
320 		rdac_pg = &h->ctlr->mode_select.legacy;
321 		memset(rdac_pg, 0, data_size);
322 		common = &rdac_pg->common;
323 		rdac_pg->page_code = RDAC_PAGE_CODE_REDUNDANT_CONTROLLER;
324 		rdac_pg->page_len = 0x68;
325 		lun_table = rdac_pg->lun_table;
326 	}
327 	common->rdac_mode[1] = RDAC_MODE_TRANSFER_SPECIFIED_LUNS;
328 	common->quiescence_timeout = RDAC_QUIESCENCE_TIME;
329 	common->rdac_options = RDAC_FORCED_QUIESENCE;
330 
331 	list_for_each_entry(qdata, list, entry) {
332 		lun_table[qdata->h->lun] = 0x81;
333 	}
334 
335 	/* get request for block layer packet command */
336 	rq = get_rdac_req(sdev, &h->ctlr->mode_select, data_size, WRITE);
337 	if (!rq)
338 		return NULL;
339 
340 	/* Prepare the command. */
341 	if (h->ctlr->use_ms10) {
342 		rq->cmd[0] = MODE_SELECT_10;
343 		rq->cmd[7] = data_size >> 8;
344 		rq->cmd[8] = data_size & 0xff;
345 	} else {
346 		rq->cmd[0] = MODE_SELECT;
347 		rq->cmd[4] = data_size;
348 	}
349 	rq->cmd_len = COMMAND_SIZE(rq->cmd[0]);
350 
351 	rq->sense = h->sense;
352 	memset(rq->sense, 0, SCSI_SENSE_BUFFERSIZE);
353 	rq->sense_len = 0;
354 
355 	return rq;
356 }
357 
358 static void release_controller(struct kref *kref)
359 {
360 	struct rdac_controller *ctlr;
361 	ctlr = container_of(kref, struct rdac_controller, kref);
362 
363 	list_del(&ctlr->node);
364 	kfree(ctlr);
365 }
366 
367 static struct rdac_controller *get_controller(int index, char *array_name,
368 			u8 *array_id, struct scsi_device *sdev)
369 {
370 	struct rdac_controller *ctlr, *tmp;
371 
372 	list_for_each_entry(tmp, &ctlr_list, node) {
373 		if ((memcmp(tmp->array_id, array_id, UNIQUE_ID_LEN) == 0) &&
374 			  (tmp->index == index) &&
375 			  (tmp->host == sdev->host)) {
376 			kref_get(&tmp->kref);
377 			return tmp;
378 		}
379 	}
380 	ctlr = kmalloc(sizeof(*ctlr), GFP_ATOMIC);
381 	if (!ctlr)
382 		return NULL;
383 
384 	/* initialize fields of controller */
385 	memcpy(ctlr->array_id, array_id, UNIQUE_ID_LEN);
386 	ctlr->index = index;
387 	ctlr->host = sdev->host;
388 	memcpy(ctlr->array_name, array_name, ARRAY_LABEL_LEN);
389 
390 	kref_init(&ctlr->kref);
391 	ctlr->use_ms10 = -1;
392 	ctlr->ms_queued = 0;
393 	ctlr->ms_sdev = NULL;
394 	spin_lock_init(&ctlr->ms_lock);
395 	INIT_WORK(&ctlr->ms_work, send_mode_select);
396 	INIT_LIST_HEAD(&ctlr->ms_head);
397 	list_add(&ctlr->node, &ctlr_list);
398 	INIT_LIST_HEAD(&ctlr->dh_list);
399 
400 	return ctlr;
401 }
402 
403 static int submit_inquiry(struct scsi_device *sdev, int page_code,
404 			  unsigned int len, struct rdac_dh_data *h)
405 {
406 	struct request *rq;
407 	struct request_queue *q = sdev->request_queue;
408 	int err = SCSI_DH_RES_TEMP_UNAVAIL;
409 
410 	rq = get_rdac_req(sdev, &h->inq, len, READ);
411 	if (!rq)
412 		goto done;
413 
414 	/* Prepare the command. */
415 	rq->cmd[0] = INQUIRY;
416 	rq->cmd[1] = 1;
417 	rq->cmd[2] = page_code;
418 	rq->cmd[4] = len;
419 	rq->cmd_len = COMMAND_SIZE(INQUIRY);
420 
421 	rq->sense = h->sense;
422 	memset(rq->sense, 0, SCSI_SENSE_BUFFERSIZE);
423 	rq->sense_len = 0;
424 
425 	err = blk_execute_rq(q, NULL, rq, 1);
426 	if (err == -EIO)
427 		err = SCSI_DH_IO;
428 
429 	blk_put_request(rq);
430 done:
431 	return err;
432 }
433 
434 static int get_lun_info(struct scsi_device *sdev, struct rdac_dh_data *h,
435 			char *array_name, u8 *array_id)
436 {
437 	int err, i;
438 	struct c8_inquiry *inqp;
439 
440 	err = submit_inquiry(sdev, 0xC8, sizeof(struct c8_inquiry), h);
441 	if (err == SCSI_DH_OK) {
442 		inqp = &h->inq.c8;
443 		if (inqp->page_code != 0xc8)
444 			return SCSI_DH_NOSYS;
445 		if (inqp->page_id[0] != 'e' || inqp->page_id[1] != 'd' ||
446 		    inqp->page_id[2] != 'i' || inqp->page_id[3] != 'd')
447 			return SCSI_DH_NOSYS;
448 		h->lun = inqp->lun[7]; /* Uses only the last byte */
449 
450 		for(i=0; i<ARRAY_LABEL_LEN-1; ++i)
451 			*(array_name+i) = inqp->array_user_label[(2*i)+1];
452 
453 		*(array_name+ARRAY_LABEL_LEN-1) = '\0';
454 		memset(array_id, 0, UNIQUE_ID_LEN);
455 		memcpy(array_id, inqp->array_unique_id, inqp->array_uniq_id_len);
456 	}
457 	return err;
458 }
459 
460 static int check_ownership(struct scsi_device *sdev, struct rdac_dh_data *h)
461 {
462 	int err, access_state;
463 	struct rdac_dh_data *tmp;
464 	struct c9_inquiry *inqp;
465 
466 	h->state = RDAC_STATE_ACTIVE;
467 	err = submit_inquiry(sdev, 0xC9, sizeof(struct c9_inquiry), h);
468 	if (err == SCSI_DH_OK) {
469 		inqp = &h->inq.c9;
470 		/* detect the operating mode */
471 		if ((inqp->avte_cvp >> 5) & 0x1)
472 			h->mode = RDAC_MODE_IOSHIP; /* LUN in IOSHIP mode */
473 		else if (inqp->avte_cvp >> 7)
474 			h->mode = RDAC_MODE_AVT; /* LUN in AVT mode */
475 		else
476 			h->mode = RDAC_MODE; /* LUN in RDAC mode */
477 
478 		/* Update ownership */
479 		if (inqp->avte_cvp & 0x1) {
480 			h->lun_state = RDAC_LUN_OWNED;
481 			access_state = SCSI_ACCESS_STATE_OPTIMAL;
482 		} else {
483 			h->lun_state = RDAC_LUN_UNOWNED;
484 			if (h->mode == RDAC_MODE) {
485 				h->state = RDAC_STATE_PASSIVE;
486 				access_state = SCSI_ACCESS_STATE_STANDBY;
487 			} else
488 				access_state = SCSI_ACCESS_STATE_ACTIVE;
489 		}
490 
491 		/* Update path prio*/
492 		if (inqp->path_prio & 0x1) {
493 			h->preferred = RDAC_PREFERRED;
494 			access_state |= SCSI_ACCESS_STATE_PREFERRED;
495 		} else
496 			h->preferred = RDAC_NON_PREFERRED;
497 		rcu_read_lock();
498 		list_for_each_entry_rcu(tmp, &h->ctlr->dh_list, node) {
499 			/* h->sdev should always be valid */
500 			BUG_ON(!tmp->sdev);
501 			tmp->sdev->access_state = access_state;
502 		}
503 		rcu_read_unlock();
504 	}
505 
506 	return err;
507 }
508 
509 static int initialize_controller(struct scsi_device *sdev,
510 		struct rdac_dh_data *h, char *array_name, u8 *array_id)
511 {
512 	int err, index;
513 	struct c4_inquiry *inqp;
514 
515 	err = submit_inquiry(sdev, 0xC4, sizeof(struct c4_inquiry), h);
516 	if (err == SCSI_DH_OK) {
517 		inqp = &h->inq.c4;
518 		/* get the controller index */
519 		if (inqp->slot_id[1] == 0x31)
520 			index = 0;
521 		else
522 			index = 1;
523 
524 		spin_lock(&list_lock);
525 		h->ctlr = get_controller(index, array_name, array_id, sdev);
526 		if (!h->ctlr)
527 			err = SCSI_DH_RES_TEMP_UNAVAIL;
528 		else {
529 			list_add_rcu(&h->node, &h->ctlr->dh_list);
530 			h->sdev = sdev;
531 		}
532 		spin_unlock(&list_lock);
533 	}
534 	return err;
535 }
536 
537 static int set_mode_select(struct scsi_device *sdev, struct rdac_dh_data *h)
538 {
539 	int err;
540 	struct c2_inquiry *inqp;
541 
542 	err = submit_inquiry(sdev, 0xC2, sizeof(struct c2_inquiry), h);
543 	if (err == SCSI_DH_OK) {
544 		inqp = &h->inq.c2;
545 		/*
546 		 * If more than MODE6_MAX_LUN luns are supported, use
547 		 * mode select 10
548 		 */
549 		if (inqp->max_lun_supported >= MODE6_MAX_LUN)
550 			h->ctlr->use_ms10 = 1;
551 		else
552 			h->ctlr->use_ms10 = 0;
553 	}
554 	return err;
555 }
556 
557 static int mode_select_handle_sense(struct scsi_device *sdev,
558 					unsigned char *sensebuf)
559 {
560 	struct scsi_sense_hdr sense_hdr;
561 	int err = SCSI_DH_IO, ret;
562 	struct rdac_dh_data *h = sdev->handler_data;
563 
564 	ret = scsi_normalize_sense(sensebuf, SCSI_SENSE_BUFFERSIZE, &sense_hdr);
565 	if (!ret)
566 		goto done;
567 
568 	switch (sense_hdr.sense_key) {
569 	case NO_SENSE:
570 	case ABORTED_COMMAND:
571 	case UNIT_ATTENTION:
572 		err = SCSI_DH_RETRY;
573 		break;
574 	case NOT_READY:
575 		if (sense_hdr.asc == 0x04 && sense_hdr.ascq == 0x01)
576 			/* LUN Not Ready and is in the Process of Becoming
577 			 * Ready
578 			 */
579 			err = SCSI_DH_RETRY;
580 		break;
581 	case ILLEGAL_REQUEST:
582 		if (sense_hdr.asc == 0x91 && sense_hdr.ascq == 0x36)
583 			/*
584 			 * Command Lock contention
585 			 */
586 			err = SCSI_DH_IMM_RETRY;
587 		break;
588 	default:
589 		break;
590 	}
591 
592 	RDAC_LOG(RDAC_LOG_FAILOVER, sdev, "array %s, ctlr %d, "
593 		"MODE_SELECT returned with sense %02x/%02x/%02x",
594 		(char *) h->ctlr->array_name, h->ctlr->index,
595 		sense_hdr.sense_key, sense_hdr.asc, sense_hdr.ascq);
596 
597 done:
598 	return err;
599 }
600 
601 static void send_mode_select(struct work_struct *work)
602 {
603 	struct rdac_controller *ctlr =
604 		container_of(work, struct rdac_controller, ms_work);
605 	struct request *rq;
606 	struct scsi_device *sdev = ctlr->ms_sdev;
607 	struct rdac_dh_data *h = sdev->handler_data;
608 	struct request_queue *q = sdev->request_queue;
609 	int err, retry_cnt = RDAC_RETRY_COUNT;
610 	struct rdac_queue_data *tmp, *qdata;
611 	LIST_HEAD(list);
612 
613 	spin_lock(&ctlr->ms_lock);
614 	list_splice_init(&ctlr->ms_head, &list);
615 	ctlr->ms_queued = 0;
616 	ctlr->ms_sdev = NULL;
617 	spin_unlock(&ctlr->ms_lock);
618 
619 retry:
620 	err = SCSI_DH_RES_TEMP_UNAVAIL;
621 	rq = rdac_failover_get(sdev, h, &list);
622 	if (!rq)
623 		goto done;
624 
625 	RDAC_LOG(RDAC_LOG_FAILOVER, sdev, "array %s, ctlr %d, "
626 		"%s MODE_SELECT command",
627 		(char *) h->ctlr->array_name, h->ctlr->index,
628 		(retry_cnt == RDAC_RETRY_COUNT) ? "queueing" : "retrying");
629 
630 	err = blk_execute_rq(q, NULL, rq, 1);
631 	blk_put_request(rq);
632 	if (err != SCSI_DH_OK) {
633 		err = mode_select_handle_sense(sdev, h->sense);
634 		if (err == SCSI_DH_RETRY && retry_cnt--)
635 			goto retry;
636 		if (err == SCSI_DH_IMM_RETRY)
637 			goto retry;
638 	}
639 	if (err == SCSI_DH_OK) {
640 		h->state = RDAC_STATE_ACTIVE;
641 		RDAC_LOG(RDAC_LOG_FAILOVER, sdev, "array %s, ctlr %d, "
642 				"MODE_SELECT completed",
643 				(char *) h->ctlr->array_name, h->ctlr->index);
644 	}
645 
646 done:
647 	list_for_each_entry_safe(qdata, tmp, &list, entry) {
648 		list_del(&qdata->entry);
649 		if (err == SCSI_DH_OK)
650 			qdata->h->state = RDAC_STATE_ACTIVE;
651 		if (qdata->callback_fn)
652 			qdata->callback_fn(qdata->callback_data, err);
653 		kfree(qdata);
654 	}
655 	return;
656 }
657 
658 static int queue_mode_select(struct scsi_device *sdev,
659 				activate_complete fn, void *data)
660 {
661 	struct rdac_queue_data *qdata;
662 	struct rdac_controller *ctlr;
663 
664 	qdata = kzalloc(sizeof(*qdata), GFP_KERNEL);
665 	if (!qdata)
666 		return SCSI_DH_RETRY;
667 
668 	qdata->h = sdev->handler_data;
669 	qdata->callback_fn = fn;
670 	qdata->callback_data = data;
671 
672 	ctlr = qdata->h->ctlr;
673 	spin_lock(&ctlr->ms_lock);
674 	list_add_tail(&qdata->entry, &ctlr->ms_head);
675 	if (!ctlr->ms_queued) {
676 		ctlr->ms_queued = 1;
677 		ctlr->ms_sdev = sdev;
678 		queue_work(kmpath_rdacd, &ctlr->ms_work);
679 	}
680 	spin_unlock(&ctlr->ms_lock);
681 	return SCSI_DH_OK;
682 }
683 
684 static int rdac_activate(struct scsi_device *sdev,
685 			activate_complete fn, void *data)
686 {
687 	struct rdac_dh_data *h = sdev->handler_data;
688 	int err = SCSI_DH_OK;
689 	int act = 0;
690 
691 	err = check_ownership(sdev, h);
692 	if (err != SCSI_DH_OK)
693 		goto done;
694 
695 	switch (h->mode) {
696 	case RDAC_MODE:
697 		if (h->lun_state == RDAC_LUN_UNOWNED)
698 			act = 1;
699 		break;
700 	case RDAC_MODE_IOSHIP:
701 		if ((h->lun_state == RDAC_LUN_UNOWNED) &&
702 		    (h->preferred == RDAC_PREFERRED))
703 			act = 1;
704 		break;
705 	default:
706 		break;
707 	}
708 
709 	if (act) {
710 		err = queue_mode_select(sdev, fn, data);
711 		if (err == SCSI_DH_OK)
712 			return 0;
713 	}
714 done:
715 	if (fn)
716 		fn(data, err);
717 	return 0;
718 }
719 
720 static int rdac_prep_fn(struct scsi_device *sdev, struct request *req)
721 {
722 	struct rdac_dh_data *h = sdev->handler_data;
723 	int ret = BLKPREP_OK;
724 
725 	if (h->state != RDAC_STATE_ACTIVE) {
726 		ret = BLKPREP_KILL;
727 		req->rq_flags |= RQF_QUIET;
728 	}
729 	return ret;
730 
731 }
732 
733 static int rdac_check_sense(struct scsi_device *sdev,
734 				struct scsi_sense_hdr *sense_hdr)
735 {
736 	struct rdac_dh_data *h = sdev->handler_data;
737 
738 	RDAC_LOG(RDAC_LOG_SENSE, sdev, "array %s, ctlr %d, "
739 			"I/O returned with sense %02x/%02x/%02x",
740 			(char *) h->ctlr->array_name, h->ctlr->index,
741 			sense_hdr->sense_key, sense_hdr->asc, sense_hdr->ascq);
742 
743 	switch (sense_hdr->sense_key) {
744 	case NOT_READY:
745 		if (sense_hdr->asc == 0x04 && sense_hdr->ascq == 0x01)
746 			/* LUN Not Ready - Logical Unit Not Ready and is in
747 			* the process of becoming ready
748 			* Just retry.
749 			*/
750 			return ADD_TO_MLQUEUE;
751 		if (sense_hdr->asc == 0x04 && sense_hdr->ascq == 0x81)
752 			/* LUN Not Ready - Storage firmware incompatible
753 			 * Manual code synchonisation required.
754 			 *
755 			 * Nothing we can do here. Try to bypass the path.
756 			 */
757 			return SUCCESS;
758 		if (sense_hdr->asc == 0x04 && sense_hdr->ascq == 0xA1)
759 			/* LUN Not Ready - Quiescense in progress
760 			 *
761 			 * Just retry and wait.
762 			 */
763 			return ADD_TO_MLQUEUE;
764 		if (sense_hdr->asc == 0xA1  && sense_hdr->ascq == 0x02)
765 			/* LUN Not Ready - Quiescense in progress
766 			 * or has been achieved
767 			 * Just retry.
768 			 */
769 			return ADD_TO_MLQUEUE;
770 		break;
771 	case ILLEGAL_REQUEST:
772 		if (sense_hdr->asc == 0x94 && sense_hdr->ascq == 0x01) {
773 			/* Invalid Request - Current Logical Unit Ownership.
774 			 * Controller is not the current owner of the LUN,
775 			 * Fail the path, so that the other path be used.
776 			 */
777 			h->state = RDAC_STATE_PASSIVE;
778 			return SUCCESS;
779 		}
780 		break;
781 	case UNIT_ATTENTION:
782 		if (sense_hdr->asc == 0x29 && sense_hdr->ascq == 0x00)
783 			/*
784 			 * Power On, Reset, or Bus Device Reset, just retry.
785 			 */
786 			return ADD_TO_MLQUEUE;
787 		if (sense_hdr->asc == 0x8b && sense_hdr->ascq == 0x02)
788 			/*
789 			 * Quiescence in progress , just retry.
790 			 */
791 			return ADD_TO_MLQUEUE;
792 		break;
793 	}
794 	/* success just means we do not care what scsi-ml does */
795 	return SCSI_RETURN_NOT_HANDLED;
796 }
797 
798 static int rdac_bus_attach(struct scsi_device *sdev)
799 {
800 	struct rdac_dh_data *h;
801 	int err;
802 	char array_name[ARRAY_LABEL_LEN];
803 	char array_id[UNIQUE_ID_LEN];
804 
805 	h = kzalloc(sizeof(*h) , GFP_KERNEL);
806 	if (!h)
807 		return -ENOMEM;
808 	h->lun = UNINITIALIZED_LUN;
809 	h->state = RDAC_STATE_ACTIVE;
810 
811 	err = get_lun_info(sdev, h, array_name, array_id);
812 	if (err != SCSI_DH_OK)
813 		goto failed;
814 
815 	err = initialize_controller(sdev, h, array_name, array_id);
816 	if (err != SCSI_DH_OK)
817 		goto failed;
818 
819 	err = check_ownership(sdev, h);
820 	if (err != SCSI_DH_OK)
821 		goto clean_ctlr;
822 
823 	err = set_mode_select(sdev, h);
824 	if (err != SCSI_DH_OK)
825 		goto clean_ctlr;
826 
827 	sdev_printk(KERN_NOTICE, sdev,
828 		    "%s: LUN %d (%s) (%s)\n",
829 		    RDAC_NAME, h->lun, mode[(int)h->mode],
830 		    lun_state[(int)h->lun_state]);
831 
832 	sdev->handler_data = h;
833 	return 0;
834 
835 clean_ctlr:
836 	spin_lock(&list_lock);
837 	kref_put(&h->ctlr->kref, release_controller);
838 	spin_unlock(&list_lock);
839 
840 failed:
841 	kfree(h);
842 	return -EINVAL;
843 }
844 
845 static void rdac_bus_detach( struct scsi_device *sdev )
846 {
847 	struct rdac_dh_data *h = sdev->handler_data;
848 
849 	if (h->ctlr && h->ctlr->ms_queued)
850 		flush_workqueue(kmpath_rdacd);
851 
852 	spin_lock(&list_lock);
853 	if (h->ctlr) {
854 		list_del_rcu(&h->node);
855 		h->sdev = NULL;
856 		kref_put(&h->ctlr->kref, release_controller);
857 	}
858 	spin_unlock(&list_lock);
859 	sdev->handler_data = NULL;
860 	kfree(h);
861 }
862 
863 static struct scsi_device_handler rdac_dh = {
864 	.name = RDAC_NAME,
865 	.module = THIS_MODULE,
866 	.prep_fn = rdac_prep_fn,
867 	.check_sense = rdac_check_sense,
868 	.attach = rdac_bus_attach,
869 	.detach = rdac_bus_detach,
870 	.activate = rdac_activate,
871 };
872 
873 static int __init rdac_init(void)
874 {
875 	int r;
876 
877 	r = scsi_register_device_handler(&rdac_dh);
878 	if (r != 0) {
879 		printk(KERN_ERR "Failed to register scsi device handler.");
880 		goto done;
881 	}
882 
883 	/*
884 	 * Create workqueue to handle mode selects for rdac
885 	 */
886 	kmpath_rdacd = create_singlethread_workqueue("kmpath_rdacd");
887 	if (!kmpath_rdacd) {
888 		scsi_unregister_device_handler(&rdac_dh);
889 		printk(KERN_ERR "kmpath_rdacd creation failed.\n");
890 
891 		r = -EINVAL;
892 	}
893 done:
894 	return r;
895 }
896 
897 static void __exit rdac_exit(void)
898 {
899 	destroy_workqueue(kmpath_rdacd);
900 	scsi_unregister_device_handler(&rdac_dh);
901 }
902 
903 module_init(rdac_init);
904 module_exit(rdac_exit);
905 
906 MODULE_DESCRIPTION("Multipath LSI/Engenio/NetApp E-Series RDAC driver");
907 MODULE_AUTHOR("Mike Christie, Chandra Seetharaman");
908 MODULE_VERSION("01.00.0000.0000");
909 MODULE_LICENSE("GPL");
910