xref: /linux/drivers/scsi/device_handler/scsi_dh_rdac.c (revision e5c86679d5e864947a52fb31e45a425dea3e7fa9)
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 	union			{
209 		struct c2_inquiry c2;
210 		struct c4_inquiry c4;
211 		struct c8_inquiry c8;
212 		struct c9_inquiry c9;
213 	} inq;
214 };
215 
216 static const char *mode[] = {
217 	"RDAC",
218 	"AVT",
219 	"IOSHIP",
220 };
221 static const char *lun_state[] =
222 {
223 	"unowned",
224 	"owned",
225 };
226 
227 struct rdac_queue_data {
228 	struct list_head	entry;
229 	struct rdac_dh_data	*h;
230 	activate_complete	callback_fn;
231 	void			*callback_data;
232 };
233 
234 static LIST_HEAD(ctlr_list);
235 static DEFINE_SPINLOCK(list_lock);
236 static struct workqueue_struct *kmpath_rdacd;
237 static void send_mode_select(struct work_struct *work);
238 
239 /*
240  * module parameter to enable rdac debug logging.
241  * 2 bits for each type of logging, only two types defined for now
242  * Can be enhanced if required at later point
243  */
244 static int rdac_logging = 1;
245 module_param(rdac_logging, int, S_IRUGO|S_IWUSR);
246 MODULE_PARM_DESC(rdac_logging, "A bit mask of rdac logging levels, "
247 		"Default is 1 - failover logging enabled, "
248 		"set it to 0xF to enable all the logs");
249 
250 #define RDAC_LOG_FAILOVER	0
251 #define RDAC_LOG_SENSE		2
252 
253 #define RDAC_LOG_BITS		2
254 
255 #define RDAC_LOG_LEVEL(SHIFT)  \
256 	((rdac_logging >> (SHIFT)) & ((1 << (RDAC_LOG_BITS)) - 1))
257 
258 #define RDAC_LOG(SHIFT, sdev, f, arg...) \
259 do { \
260 	if (unlikely(RDAC_LOG_LEVEL(SHIFT))) \
261 		sdev_printk(KERN_INFO, sdev, RDAC_NAME ": " f "\n", ## arg); \
262 } while (0);
263 
264 static unsigned int rdac_failover_get(struct rdac_controller *ctlr,
265 				      struct list_head *list,
266 				      unsigned char *cdb)
267 {
268 	struct scsi_device *sdev = ctlr->ms_sdev;
269 	struct rdac_dh_data *h = sdev->handler_data;
270 	struct rdac_mode_common *common;
271 	unsigned data_size;
272 	struct rdac_queue_data *qdata;
273 	u8 *lun_table;
274 
275 	if (h->ctlr->use_ms10) {
276 		struct rdac_pg_expanded *rdac_pg;
277 
278 		data_size = sizeof(struct rdac_pg_expanded);
279 		rdac_pg = &h->ctlr->mode_select.expanded;
280 		memset(rdac_pg, 0, data_size);
281 		common = &rdac_pg->common;
282 		rdac_pg->page_code = RDAC_PAGE_CODE_REDUNDANT_CONTROLLER + 0x40;
283 		rdac_pg->subpage_code = 0x1;
284 		rdac_pg->page_len[0] = 0x01;
285 		rdac_pg->page_len[1] = 0x28;
286 		lun_table = rdac_pg->lun_table;
287 	} else {
288 		struct rdac_pg_legacy *rdac_pg;
289 
290 		data_size = sizeof(struct rdac_pg_legacy);
291 		rdac_pg = &h->ctlr->mode_select.legacy;
292 		memset(rdac_pg, 0, data_size);
293 		common = &rdac_pg->common;
294 		rdac_pg->page_code = RDAC_PAGE_CODE_REDUNDANT_CONTROLLER;
295 		rdac_pg->page_len = 0x68;
296 		lun_table = rdac_pg->lun_table;
297 	}
298 	common->rdac_mode[1] = RDAC_MODE_TRANSFER_SPECIFIED_LUNS;
299 	common->quiescence_timeout = RDAC_QUIESCENCE_TIME;
300 	common->rdac_options = RDAC_FORCED_QUIESENCE;
301 
302 	list_for_each_entry(qdata, list, entry) {
303 		lun_table[qdata->h->lun] = 0x81;
304 	}
305 
306 	/* Prepare the command. */
307 	if (h->ctlr->use_ms10) {
308 		cdb[0] = MODE_SELECT_10;
309 		cdb[7] = data_size >> 8;
310 		cdb[8] = data_size & 0xff;
311 	} else {
312 		cdb[0] = MODE_SELECT;
313 		cdb[4] = data_size;
314 	}
315 
316 	return data_size;
317 }
318 
319 static void release_controller(struct kref *kref)
320 {
321 	struct rdac_controller *ctlr;
322 	ctlr = container_of(kref, struct rdac_controller, kref);
323 
324 	list_del(&ctlr->node);
325 	kfree(ctlr);
326 }
327 
328 static struct rdac_controller *get_controller(int index, char *array_name,
329 			u8 *array_id, struct scsi_device *sdev)
330 {
331 	struct rdac_controller *ctlr, *tmp;
332 
333 	list_for_each_entry(tmp, &ctlr_list, node) {
334 		if ((memcmp(tmp->array_id, array_id, UNIQUE_ID_LEN) == 0) &&
335 			  (tmp->index == index) &&
336 			  (tmp->host == sdev->host)) {
337 			kref_get(&tmp->kref);
338 			return tmp;
339 		}
340 	}
341 	ctlr = kmalloc(sizeof(*ctlr), GFP_ATOMIC);
342 	if (!ctlr)
343 		return NULL;
344 
345 	/* initialize fields of controller */
346 	memcpy(ctlr->array_id, array_id, UNIQUE_ID_LEN);
347 	ctlr->index = index;
348 	ctlr->host = sdev->host;
349 	memcpy(ctlr->array_name, array_name, ARRAY_LABEL_LEN);
350 
351 	kref_init(&ctlr->kref);
352 	ctlr->use_ms10 = -1;
353 	ctlr->ms_queued = 0;
354 	ctlr->ms_sdev = NULL;
355 	spin_lock_init(&ctlr->ms_lock);
356 	INIT_WORK(&ctlr->ms_work, send_mode_select);
357 	INIT_LIST_HEAD(&ctlr->ms_head);
358 	list_add(&ctlr->node, &ctlr_list);
359 	INIT_LIST_HEAD(&ctlr->dh_list);
360 
361 	return ctlr;
362 }
363 
364 static int get_lun_info(struct scsi_device *sdev, struct rdac_dh_data *h,
365 			char *array_name, u8 *array_id)
366 {
367 	int err = SCSI_DH_IO, i;
368 	struct c8_inquiry *inqp = &h->inq.c8;
369 
370 	if (!scsi_get_vpd_page(sdev, 0xC8, (unsigned char *)inqp,
371 			       sizeof(struct c8_inquiry))) {
372 		if (inqp->page_code != 0xc8)
373 			return SCSI_DH_NOSYS;
374 		if (inqp->page_id[0] != 'e' || inqp->page_id[1] != 'd' ||
375 		    inqp->page_id[2] != 'i' || inqp->page_id[3] != 'd')
376 			return SCSI_DH_NOSYS;
377 		h->lun = inqp->lun[7]; /* Uses only the last byte */
378 
379 		for(i=0; i<ARRAY_LABEL_LEN-1; ++i)
380 			*(array_name+i) = inqp->array_user_label[(2*i)+1];
381 
382 		*(array_name+ARRAY_LABEL_LEN-1) = '\0';
383 		memset(array_id, 0, UNIQUE_ID_LEN);
384 		memcpy(array_id, inqp->array_unique_id, inqp->array_uniq_id_len);
385 		err = SCSI_DH_OK;
386 	}
387 	return err;
388 }
389 
390 static int check_ownership(struct scsi_device *sdev, struct rdac_dh_data *h)
391 {
392 	int err = SCSI_DH_IO, access_state;
393 	struct rdac_dh_data *tmp;
394 	struct c9_inquiry *inqp = &h->inq.c9;
395 
396 	h->state = RDAC_STATE_ACTIVE;
397 	if (!scsi_get_vpd_page(sdev, 0xC9, (unsigned char *)inqp,
398 			       sizeof(struct c9_inquiry))) {
399 		/* detect the operating mode */
400 		if ((inqp->avte_cvp >> 5) & 0x1)
401 			h->mode = RDAC_MODE_IOSHIP; /* LUN in IOSHIP mode */
402 		else if (inqp->avte_cvp >> 7)
403 			h->mode = RDAC_MODE_AVT; /* LUN in AVT mode */
404 		else
405 			h->mode = RDAC_MODE; /* LUN in RDAC mode */
406 
407 		/* Update ownership */
408 		if (inqp->avte_cvp & 0x1) {
409 			h->lun_state = RDAC_LUN_OWNED;
410 			access_state = SCSI_ACCESS_STATE_OPTIMAL;
411 		} else {
412 			h->lun_state = RDAC_LUN_UNOWNED;
413 			if (h->mode == RDAC_MODE) {
414 				h->state = RDAC_STATE_PASSIVE;
415 				access_state = SCSI_ACCESS_STATE_STANDBY;
416 			} else
417 				access_state = SCSI_ACCESS_STATE_ACTIVE;
418 		}
419 
420 		/* Update path prio*/
421 		if (inqp->path_prio & 0x1) {
422 			h->preferred = RDAC_PREFERRED;
423 			access_state |= SCSI_ACCESS_STATE_PREFERRED;
424 		} else
425 			h->preferred = RDAC_NON_PREFERRED;
426 		rcu_read_lock();
427 		list_for_each_entry_rcu(tmp, &h->ctlr->dh_list, node) {
428 			/* h->sdev should always be valid */
429 			BUG_ON(!tmp->sdev);
430 			tmp->sdev->access_state = access_state;
431 		}
432 		rcu_read_unlock();
433 		err = SCSI_DH_OK;
434 	}
435 
436 	return err;
437 }
438 
439 static int initialize_controller(struct scsi_device *sdev,
440 		struct rdac_dh_data *h, char *array_name, u8 *array_id)
441 {
442 	int err = SCSI_DH_IO, index;
443 	struct c4_inquiry *inqp = &h->inq.c4;
444 
445 	if (!scsi_get_vpd_page(sdev, 0xC4, (unsigned char *)inqp,
446 			       sizeof(struct c4_inquiry))) {
447 		/* get the controller index */
448 		if (inqp->slot_id[1] == 0x31)
449 			index = 0;
450 		else
451 			index = 1;
452 
453 		spin_lock(&list_lock);
454 		h->ctlr = get_controller(index, array_name, array_id, sdev);
455 		if (!h->ctlr)
456 			err = SCSI_DH_RES_TEMP_UNAVAIL;
457 		else {
458 			list_add_rcu(&h->node, &h->ctlr->dh_list);
459 			h->sdev = sdev;
460 		}
461 		spin_unlock(&list_lock);
462 		err = SCSI_DH_OK;
463 	}
464 	return err;
465 }
466 
467 static int set_mode_select(struct scsi_device *sdev, struct rdac_dh_data *h)
468 {
469 	int err = SCSI_DH_IO;
470 	struct c2_inquiry *inqp = &h->inq.c2;
471 
472 	if (!scsi_get_vpd_page(sdev, 0xC2, (unsigned char *)inqp,
473 			       sizeof(struct c2_inquiry))) {
474 		/*
475 		 * If more than MODE6_MAX_LUN luns are supported, use
476 		 * mode select 10
477 		 */
478 		if (inqp->max_lun_supported >= MODE6_MAX_LUN)
479 			h->ctlr->use_ms10 = 1;
480 		else
481 			h->ctlr->use_ms10 = 0;
482 		err = SCSI_DH_OK;
483 	}
484 	return err;
485 }
486 
487 static int mode_select_handle_sense(struct scsi_device *sdev,
488 				    struct scsi_sense_hdr *sense_hdr)
489 {
490 	int err = SCSI_DH_IO;
491 	struct rdac_dh_data *h = sdev->handler_data;
492 
493 	if (!scsi_sense_valid(sense_hdr))
494 		goto done;
495 
496 	switch (sense_hdr->sense_key) {
497 	case NO_SENSE:
498 	case ABORTED_COMMAND:
499 	case UNIT_ATTENTION:
500 		err = SCSI_DH_RETRY;
501 		break;
502 	case NOT_READY:
503 		if (sense_hdr->asc == 0x04 && sense_hdr->ascq == 0x01)
504 			/* LUN Not Ready and is in the Process of Becoming
505 			 * Ready
506 			 */
507 			err = SCSI_DH_RETRY;
508 		break;
509 	case ILLEGAL_REQUEST:
510 		if (sense_hdr->asc == 0x91 && sense_hdr->ascq == 0x36)
511 			/*
512 			 * Command Lock contention
513 			 */
514 			err = SCSI_DH_IMM_RETRY;
515 		break;
516 	default:
517 		break;
518 	}
519 
520 	RDAC_LOG(RDAC_LOG_FAILOVER, sdev, "array %s, ctlr %d, "
521 		"MODE_SELECT returned with sense %02x/%02x/%02x",
522 		(char *) h->ctlr->array_name, h->ctlr->index,
523 		sense_hdr->sense_key, sense_hdr->asc, sense_hdr->ascq);
524 
525 done:
526 	return err;
527 }
528 
529 static void send_mode_select(struct work_struct *work)
530 {
531 	struct rdac_controller *ctlr =
532 		container_of(work, struct rdac_controller, ms_work);
533 	struct scsi_device *sdev = ctlr->ms_sdev;
534 	struct rdac_dh_data *h = sdev->handler_data;
535 	int err = SCSI_DH_OK, retry_cnt = RDAC_RETRY_COUNT;
536 	struct rdac_queue_data *tmp, *qdata;
537 	LIST_HEAD(list);
538 	unsigned char cdb[COMMAND_SIZE(MODE_SELECT_10)];
539 	struct scsi_sense_hdr sshdr;
540 	unsigned int data_size;
541 	u64 req_flags = REQ_FAILFAST_DEV | REQ_FAILFAST_TRANSPORT |
542 		REQ_FAILFAST_DRIVER;
543 
544 	spin_lock(&ctlr->ms_lock);
545 	list_splice_init(&ctlr->ms_head, &list);
546 	ctlr->ms_queued = 0;
547 	ctlr->ms_sdev = NULL;
548 	spin_unlock(&ctlr->ms_lock);
549 
550  retry:
551 	data_size = rdac_failover_get(ctlr, &list, cdb);
552 
553 	RDAC_LOG(RDAC_LOG_FAILOVER, sdev, "array %s, ctlr %d, "
554 		"%s MODE_SELECT command",
555 		(char *) h->ctlr->array_name, h->ctlr->index,
556 		(retry_cnt == RDAC_RETRY_COUNT) ? "queueing" : "retrying");
557 
558 	if (scsi_execute(sdev, cdb, DMA_TO_DEVICE, &h->ctlr->mode_select,
559 			data_size, NULL, &sshdr, RDAC_TIMEOUT * HZ,
560 			RDAC_RETRIES, req_flags, 0, NULL)) {
561 		err = mode_select_handle_sense(sdev, &sshdr);
562 		if (err == SCSI_DH_RETRY && retry_cnt--)
563 			goto retry;
564 		if (err == SCSI_DH_IMM_RETRY)
565 			goto retry;
566 	}
567 	if (err == SCSI_DH_OK) {
568 		h->state = RDAC_STATE_ACTIVE;
569 		RDAC_LOG(RDAC_LOG_FAILOVER, sdev, "array %s, ctlr %d, "
570 				"MODE_SELECT completed",
571 				(char *) h->ctlr->array_name, h->ctlr->index);
572 	}
573 
574 	list_for_each_entry_safe(qdata, tmp, &list, entry) {
575 		list_del(&qdata->entry);
576 		if (err == SCSI_DH_OK)
577 			qdata->h->state = RDAC_STATE_ACTIVE;
578 		if (qdata->callback_fn)
579 			qdata->callback_fn(qdata->callback_data, err);
580 		kfree(qdata);
581 	}
582 	return;
583 }
584 
585 static int queue_mode_select(struct scsi_device *sdev,
586 				activate_complete fn, void *data)
587 {
588 	struct rdac_queue_data *qdata;
589 	struct rdac_controller *ctlr;
590 
591 	qdata = kzalloc(sizeof(*qdata), GFP_KERNEL);
592 	if (!qdata)
593 		return SCSI_DH_RETRY;
594 
595 	qdata->h = sdev->handler_data;
596 	qdata->callback_fn = fn;
597 	qdata->callback_data = data;
598 
599 	ctlr = qdata->h->ctlr;
600 	spin_lock(&ctlr->ms_lock);
601 	list_add_tail(&qdata->entry, &ctlr->ms_head);
602 	if (!ctlr->ms_queued) {
603 		ctlr->ms_queued = 1;
604 		ctlr->ms_sdev = sdev;
605 		queue_work(kmpath_rdacd, &ctlr->ms_work);
606 	}
607 	spin_unlock(&ctlr->ms_lock);
608 	return SCSI_DH_OK;
609 }
610 
611 static int rdac_activate(struct scsi_device *sdev,
612 			activate_complete fn, void *data)
613 {
614 	struct rdac_dh_data *h = sdev->handler_data;
615 	int err = SCSI_DH_OK;
616 	int act = 0;
617 
618 	err = check_ownership(sdev, h);
619 	if (err != SCSI_DH_OK)
620 		goto done;
621 
622 	switch (h->mode) {
623 	case RDAC_MODE:
624 		if (h->lun_state == RDAC_LUN_UNOWNED)
625 			act = 1;
626 		break;
627 	case RDAC_MODE_IOSHIP:
628 		if ((h->lun_state == RDAC_LUN_UNOWNED) &&
629 		    (h->preferred == RDAC_PREFERRED))
630 			act = 1;
631 		break;
632 	default:
633 		break;
634 	}
635 
636 	if (act) {
637 		err = queue_mode_select(sdev, fn, data);
638 		if (err == SCSI_DH_OK)
639 			return 0;
640 	}
641 done:
642 	if (fn)
643 		fn(data, err);
644 	return 0;
645 }
646 
647 static int rdac_prep_fn(struct scsi_device *sdev, struct request *req)
648 {
649 	struct rdac_dh_data *h = sdev->handler_data;
650 	int ret = BLKPREP_OK;
651 
652 	if (h->state != RDAC_STATE_ACTIVE) {
653 		ret = BLKPREP_KILL;
654 		req->rq_flags |= RQF_QUIET;
655 	}
656 	return ret;
657 
658 }
659 
660 static int rdac_check_sense(struct scsi_device *sdev,
661 				struct scsi_sense_hdr *sense_hdr)
662 {
663 	struct rdac_dh_data *h = sdev->handler_data;
664 
665 	RDAC_LOG(RDAC_LOG_SENSE, sdev, "array %s, ctlr %d, "
666 			"I/O returned with sense %02x/%02x/%02x",
667 			(char *) h->ctlr->array_name, h->ctlr->index,
668 			sense_hdr->sense_key, sense_hdr->asc, sense_hdr->ascq);
669 
670 	switch (sense_hdr->sense_key) {
671 	case NOT_READY:
672 		if (sense_hdr->asc == 0x04 && sense_hdr->ascq == 0x01)
673 			/* LUN Not Ready - Logical Unit Not Ready and is in
674 			* the process of becoming ready
675 			* Just retry.
676 			*/
677 			return ADD_TO_MLQUEUE;
678 		if (sense_hdr->asc == 0x04 && sense_hdr->ascq == 0x81)
679 			/* LUN Not Ready - Storage firmware incompatible
680 			 * Manual code synchonisation required.
681 			 *
682 			 * Nothing we can do here. Try to bypass the path.
683 			 */
684 			return SUCCESS;
685 		if (sense_hdr->asc == 0x04 && sense_hdr->ascq == 0xA1)
686 			/* LUN Not Ready - Quiescense in progress
687 			 *
688 			 * Just retry and wait.
689 			 */
690 			return ADD_TO_MLQUEUE;
691 		if (sense_hdr->asc == 0xA1  && sense_hdr->ascq == 0x02)
692 			/* LUN Not Ready - Quiescense in progress
693 			 * or has been achieved
694 			 * Just retry.
695 			 */
696 			return ADD_TO_MLQUEUE;
697 		break;
698 	case ILLEGAL_REQUEST:
699 		if (sense_hdr->asc == 0x94 && sense_hdr->ascq == 0x01) {
700 			/* Invalid Request - Current Logical Unit Ownership.
701 			 * Controller is not the current owner of the LUN,
702 			 * Fail the path, so that the other path be used.
703 			 */
704 			h->state = RDAC_STATE_PASSIVE;
705 			return SUCCESS;
706 		}
707 		break;
708 	case UNIT_ATTENTION:
709 		if (sense_hdr->asc == 0x29 && sense_hdr->ascq == 0x00)
710 			/*
711 			 * Power On, Reset, or Bus Device Reset, just retry.
712 			 */
713 			return ADD_TO_MLQUEUE;
714 		if (sense_hdr->asc == 0x8b && sense_hdr->ascq == 0x02)
715 			/*
716 			 * Quiescence in progress , just retry.
717 			 */
718 			return ADD_TO_MLQUEUE;
719 		break;
720 	}
721 	/* success just means we do not care what scsi-ml does */
722 	return SCSI_RETURN_NOT_HANDLED;
723 }
724 
725 static int rdac_bus_attach(struct scsi_device *sdev)
726 {
727 	struct rdac_dh_data *h;
728 	int err;
729 	char array_name[ARRAY_LABEL_LEN];
730 	char array_id[UNIQUE_ID_LEN];
731 
732 	h = kzalloc(sizeof(*h) , GFP_KERNEL);
733 	if (!h)
734 		return -ENOMEM;
735 	h->lun = UNINITIALIZED_LUN;
736 	h->state = RDAC_STATE_ACTIVE;
737 
738 	err = get_lun_info(sdev, h, array_name, array_id);
739 	if (err != SCSI_DH_OK)
740 		goto failed;
741 
742 	err = initialize_controller(sdev, h, array_name, array_id);
743 	if (err != SCSI_DH_OK)
744 		goto failed;
745 
746 	err = check_ownership(sdev, h);
747 	if (err != SCSI_DH_OK)
748 		goto clean_ctlr;
749 
750 	err = set_mode_select(sdev, h);
751 	if (err != SCSI_DH_OK)
752 		goto clean_ctlr;
753 
754 	sdev_printk(KERN_NOTICE, sdev,
755 		    "%s: LUN %d (%s) (%s)\n",
756 		    RDAC_NAME, h->lun, mode[(int)h->mode],
757 		    lun_state[(int)h->lun_state]);
758 
759 	sdev->handler_data = h;
760 	return 0;
761 
762 clean_ctlr:
763 	spin_lock(&list_lock);
764 	kref_put(&h->ctlr->kref, release_controller);
765 	spin_unlock(&list_lock);
766 
767 failed:
768 	kfree(h);
769 	return -EINVAL;
770 }
771 
772 static void rdac_bus_detach( struct scsi_device *sdev )
773 {
774 	struct rdac_dh_data *h = sdev->handler_data;
775 
776 	if (h->ctlr && h->ctlr->ms_queued)
777 		flush_workqueue(kmpath_rdacd);
778 
779 	spin_lock(&list_lock);
780 	if (h->ctlr) {
781 		list_del_rcu(&h->node);
782 		h->sdev = NULL;
783 		kref_put(&h->ctlr->kref, release_controller);
784 	}
785 	spin_unlock(&list_lock);
786 	sdev->handler_data = NULL;
787 	kfree(h);
788 }
789 
790 static struct scsi_device_handler rdac_dh = {
791 	.name = RDAC_NAME,
792 	.module = THIS_MODULE,
793 	.prep_fn = rdac_prep_fn,
794 	.check_sense = rdac_check_sense,
795 	.attach = rdac_bus_attach,
796 	.detach = rdac_bus_detach,
797 	.activate = rdac_activate,
798 };
799 
800 static int __init rdac_init(void)
801 {
802 	int r;
803 
804 	r = scsi_register_device_handler(&rdac_dh);
805 	if (r != 0) {
806 		printk(KERN_ERR "Failed to register scsi device handler.");
807 		goto done;
808 	}
809 
810 	/*
811 	 * Create workqueue to handle mode selects for rdac
812 	 */
813 	kmpath_rdacd = create_singlethread_workqueue("kmpath_rdacd");
814 	if (!kmpath_rdacd) {
815 		scsi_unregister_device_handler(&rdac_dh);
816 		printk(KERN_ERR "kmpath_rdacd creation failed.\n");
817 
818 		r = -EINVAL;
819 	}
820 done:
821 	return r;
822 }
823 
824 static void __exit rdac_exit(void)
825 {
826 	destroy_workqueue(kmpath_rdacd);
827 	scsi_unregister_device_handler(&rdac_dh);
828 }
829 
830 module_init(rdac_init);
831 module_exit(rdac_exit);
832 
833 MODULE_DESCRIPTION("Multipath LSI/Engenio/NetApp E-Series RDAC driver");
834 MODULE_AUTHOR("Mike Christie, Chandra Seetharaman");
835 MODULE_VERSION("01.00.0000.0000");
836 MODULE_LICENSE("GPL");
837