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 rdac_mode_common *common;
269 	unsigned data_size;
270 	struct rdac_queue_data *qdata;
271 	u8 *lun_table;
272 
273 	if (ctlr->use_ms10) {
274 		struct rdac_pg_expanded *rdac_pg;
275 
276 		data_size = sizeof(struct rdac_pg_expanded);
277 		rdac_pg = &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 		lun_table = rdac_pg->lun_table;
285 	} else {
286 		struct rdac_pg_legacy *rdac_pg;
287 
288 		data_size = sizeof(struct rdac_pg_legacy);
289 		rdac_pg = &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 		lun_table = rdac_pg->lun_table;
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 	list_for_each_entry(qdata, list, entry) {
301 		lun_table[qdata->h->lun] = 0x81;
302 	}
303 
304 	/* Prepare the command. */
305 	if (ctlr->use_ms10) {
306 		cdb[0] = MODE_SELECT_10;
307 		cdb[7] = data_size >> 8;
308 		cdb[8] = data_size & 0xff;
309 	} else {
310 		cdb[0] = MODE_SELECT;
311 		cdb[4] = data_size;
312 	}
313 
314 	return data_size;
315 }
316 
317 static void release_controller(struct kref *kref)
318 {
319 	struct rdac_controller *ctlr;
320 	ctlr = container_of(kref, struct rdac_controller, kref);
321 
322 	list_del(&ctlr->node);
323 	kfree(ctlr);
324 }
325 
326 static struct rdac_controller *get_controller(int index, char *array_name,
327 			u8 *array_id, struct scsi_device *sdev)
328 {
329 	struct rdac_controller *ctlr, *tmp;
330 
331 	list_for_each_entry(tmp, &ctlr_list, node) {
332 		if ((memcmp(tmp->array_id, array_id, UNIQUE_ID_LEN) == 0) &&
333 			  (tmp->index == index) &&
334 			  (tmp->host == sdev->host)) {
335 			kref_get(&tmp->kref);
336 			return tmp;
337 		}
338 	}
339 	ctlr = kmalloc(sizeof(*ctlr), GFP_ATOMIC);
340 	if (!ctlr)
341 		return NULL;
342 
343 	/* initialize fields of controller */
344 	memcpy(ctlr->array_id, array_id, UNIQUE_ID_LEN);
345 	ctlr->index = index;
346 	ctlr->host = sdev->host;
347 	memcpy(ctlr->array_name, array_name, ARRAY_LABEL_LEN);
348 
349 	kref_init(&ctlr->kref);
350 	ctlr->use_ms10 = -1;
351 	ctlr->ms_queued = 0;
352 	ctlr->ms_sdev = NULL;
353 	spin_lock_init(&ctlr->ms_lock);
354 	INIT_WORK(&ctlr->ms_work, send_mode_select);
355 	INIT_LIST_HEAD(&ctlr->ms_head);
356 	list_add(&ctlr->node, &ctlr_list);
357 	INIT_LIST_HEAD(&ctlr->dh_list);
358 
359 	return ctlr;
360 }
361 
362 static int get_lun_info(struct scsi_device *sdev, struct rdac_dh_data *h,
363 			char *array_name, u8 *array_id)
364 {
365 	int err = SCSI_DH_IO, i;
366 	struct c8_inquiry *inqp = &h->inq.c8;
367 
368 	if (!scsi_get_vpd_page(sdev, 0xC8, (unsigned char *)inqp,
369 			       sizeof(struct c8_inquiry))) {
370 		if (inqp->page_code != 0xc8)
371 			return SCSI_DH_NOSYS;
372 		if (inqp->page_id[0] != 'e' || inqp->page_id[1] != 'd' ||
373 		    inqp->page_id[2] != 'i' || inqp->page_id[3] != 'd')
374 			return SCSI_DH_NOSYS;
375 		h->lun = inqp->lun[7]; /* Uses only the last byte */
376 
377 		for(i=0; i<ARRAY_LABEL_LEN-1; ++i)
378 			*(array_name+i) = inqp->array_user_label[(2*i)+1];
379 
380 		*(array_name+ARRAY_LABEL_LEN-1) = '\0';
381 		memset(array_id, 0, UNIQUE_ID_LEN);
382 		memcpy(array_id, inqp->array_unique_id, inqp->array_uniq_id_len);
383 		err = SCSI_DH_OK;
384 	}
385 	return err;
386 }
387 
388 static int check_ownership(struct scsi_device *sdev, struct rdac_dh_data *h)
389 {
390 	int err = SCSI_DH_IO, access_state;
391 	struct rdac_dh_data *tmp;
392 	struct c9_inquiry *inqp = &h->inq.c9;
393 
394 	h->state = RDAC_STATE_ACTIVE;
395 	if (!scsi_get_vpd_page(sdev, 0xC9, (unsigned char *)inqp,
396 			       sizeof(struct c9_inquiry))) {
397 		/* detect the operating mode */
398 		if ((inqp->avte_cvp >> 5) & 0x1)
399 			h->mode = RDAC_MODE_IOSHIP; /* LUN in IOSHIP mode */
400 		else if (inqp->avte_cvp >> 7)
401 			h->mode = RDAC_MODE_AVT; /* LUN in AVT mode */
402 		else
403 			h->mode = RDAC_MODE; /* LUN in RDAC mode */
404 
405 		/* Update ownership */
406 		if (inqp->avte_cvp & 0x1) {
407 			h->lun_state = RDAC_LUN_OWNED;
408 			access_state = SCSI_ACCESS_STATE_OPTIMAL;
409 		} else {
410 			h->lun_state = RDAC_LUN_UNOWNED;
411 			if (h->mode == RDAC_MODE) {
412 				h->state = RDAC_STATE_PASSIVE;
413 				access_state = SCSI_ACCESS_STATE_STANDBY;
414 			} else
415 				access_state = SCSI_ACCESS_STATE_ACTIVE;
416 		}
417 
418 		/* Update path prio*/
419 		if (inqp->path_prio & 0x1) {
420 			h->preferred = RDAC_PREFERRED;
421 			access_state |= SCSI_ACCESS_STATE_PREFERRED;
422 		} else
423 			h->preferred = RDAC_NON_PREFERRED;
424 		rcu_read_lock();
425 		list_for_each_entry_rcu(tmp, &h->ctlr->dh_list, node) {
426 			/* h->sdev should always be valid */
427 			BUG_ON(!tmp->sdev);
428 			tmp->sdev->access_state = access_state;
429 		}
430 		rcu_read_unlock();
431 		err = SCSI_DH_OK;
432 	}
433 
434 	return err;
435 }
436 
437 static int initialize_controller(struct scsi_device *sdev,
438 		struct rdac_dh_data *h, char *array_name, u8 *array_id)
439 {
440 	int err = SCSI_DH_IO, index;
441 	struct c4_inquiry *inqp = &h->inq.c4;
442 
443 	if (!scsi_get_vpd_page(sdev, 0xC4, (unsigned char *)inqp,
444 			       sizeof(struct c4_inquiry))) {
445 		/* get the controller index */
446 		if (inqp->slot_id[1] == 0x31)
447 			index = 0;
448 		else
449 			index = 1;
450 
451 		spin_lock(&list_lock);
452 		h->ctlr = get_controller(index, array_name, array_id, sdev);
453 		if (!h->ctlr)
454 			err = SCSI_DH_RES_TEMP_UNAVAIL;
455 		else {
456 			h->sdev = sdev;
457 			list_add_rcu(&h->node, &h->ctlr->dh_list);
458 		}
459 		spin_unlock(&list_lock);
460 		err = SCSI_DH_OK;
461 	}
462 	return err;
463 }
464 
465 static int set_mode_select(struct scsi_device *sdev, struct rdac_dh_data *h)
466 {
467 	int err = SCSI_DH_IO;
468 	struct c2_inquiry *inqp = &h->inq.c2;
469 
470 	if (!scsi_get_vpd_page(sdev, 0xC2, (unsigned char *)inqp,
471 			       sizeof(struct c2_inquiry))) {
472 		/*
473 		 * If more than MODE6_MAX_LUN luns are supported, use
474 		 * mode select 10
475 		 */
476 		if (inqp->max_lun_supported >= MODE6_MAX_LUN)
477 			h->ctlr->use_ms10 = 1;
478 		else
479 			h->ctlr->use_ms10 = 0;
480 		err = SCSI_DH_OK;
481 	}
482 	return err;
483 }
484 
485 static int mode_select_handle_sense(struct scsi_device *sdev,
486 				    struct scsi_sense_hdr *sense_hdr)
487 {
488 	int err = SCSI_DH_IO;
489 	struct rdac_dh_data *h = sdev->handler_data;
490 
491 	if (!scsi_sense_valid(sense_hdr))
492 		goto done;
493 
494 	switch (sense_hdr->sense_key) {
495 	case NO_SENSE:
496 	case ABORTED_COMMAND:
497 	case UNIT_ATTENTION:
498 		err = SCSI_DH_RETRY;
499 		break;
500 	case NOT_READY:
501 		if (sense_hdr->asc == 0x04 && sense_hdr->ascq == 0x01)
502 			/* LUN Not Ready and is in the Process of Becoming
503 			 * Ready
504 			 */
505 			err = SCSI_DH_RETRY;
506 		break;
507 	case ILLEGAL_REQUEST:
508 		if (sense_hdr->asc == 0x91 && sense_hdr->ascq == 0x36)
509 			/*
510 			 * Command Lock contention
511 			 */
512 			err = SCSI_DH_IMM_RETRY;
513 		break;
514 	default:
515 		break;
516 	}
517 
518 	RDAC_LOG(RDAC_LOG_FAILOVER, sdev, "array %s, ctlr %d, "
519 		"MODE_SELECT returned with sense %02x/%02x/%02x",
520 		(char *) h->ctlr->array_name, h->ctlr->index,
521 		sense_hdr->sense_key, sense_hdr->asc, sense_hdr->ascq);
522 
523 done:
524 	return err;
525 }
526 
527 static void send_mode_select(struct work_struct *work)
528 {
529 	struct rdac_controller *ctlr =
530 		container_of(work, struct rdac_controller, ms_work);
531 	struct scsi_device *sdev = ctlr->ms_sdev;
532 	struct rdac_dh_data *h = sdev->handler_data;
533 	int err = SCSI_DH_OK, retry_cnt = RDAC_RETRY_COUNT;
534 	struct rdac_queue_data *tmp, *qdata;
535 	LIST_HEAD(list);
536 	unsigned char cdb[MAX_COMMAND_SIZE];
537 	struct scsi_sense_hdr sshdr;
538 	unsigned int data_size;
539 	blk_opf_t req_flags = REQ_FAILFAST_DEV | REQ_FAILFAST_TRANSPORT |
540 		REQ_FAILFAST_DRIVER;
541 
542 	spin_lock(&ctlr->ms_lock);
543 	list_splice_init(&ctlr->ms_head, &list);
544 	ctlr->ms_queued = 0;
545 	ctlr->ms_sdev = NULL;
546 	spin_unlock(&ctlr->ms_lock);
547 
548  retry:
549 	memset(cdb, 0, sizeof(cdb));
550 
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 blk_status_t rdac_prep_fn(struct scsi_device *sdev, struct request *req)
648 {
649 	struct rdac_dh_data *h = sdev->handler_data;
650 
651 	if (h->state != RDAC_STATE_ACTIVE) {
652 		req->rq_flags |= RQF_QUIET;
653 		return BLK_STS_IOERR;
654 	}
655 
656 	return BLK_STS_OK;
657 }
658 
659 static enum scsi_disposition rdac_check_sense(struct scsi_device *sdev,
660 					      struct scsi_sense_hdr *sense_hdr)
661 {
662 	struct rdac_dh_data *h = sdev->handler_data;
663 
664 	RDAC_LOG(RDAC_LOG_SENSE, sdev, "array %s, ctlr %d, "
665 			"I/O returned with sense %02x/%02x/%02x",
666 			(char *) h->ctlr->array_name, h->ctlr->index,
667 			sense_hdr->sense_key, sense_hdr->asc, sense_hdr->ascq);
668 
669 	switch (sense_hdr->sense_key) {
670 	case NOT_READY:
671 		if (sense_hdr->asc == 0x04 && sense_hdr->ascq == 0x01)
672 			/* LUN Not Ready - Logical Unit Not Ready and is in
673 			* the process of becoming ready
674 			* Just retry.
675 			*/
676 			return ADD_TO_MLQUEUE;
677 		if (sense_hdr->asc == 0x04 && sense_hdr->ascq == 0x81)
678 			/* LUN Not Ready - Storage firmware incompatible
679 			 * Manual code synchonisation required.
680 			 *
681 			 * Nothing we can do here. Try to bypass the path.
682 			 */
683 			return SUCCESS;
684 		if (sense_hdr->asc == 0x04 && sense_hdr->ascq == 0xA1)
685 			/* LUN Not Ready - Quiescense in progress
686 			 *
687 			 * Just retry and wait.
688 			 */
689 			return ADD_TO_MLQUEUE;
690 		if (sense_hdr->asc == 0xA1  && sense_hdr->ascq == 0x02)
691 			/* LUN Not Ready - Quiescense in progress
692 			 * or has been achieved
693 			 * Just retry.
694 			 */
695 			return ADD_TO_MLQUEUE;
696 		break;
697 	case ILLEGAL_REQUEST:
698 		if (sense_hdr->asc == 0x94 && sense_hdr->ascq == 0x01) {
699 			/* Invalid Request - Current Logical Unit Ownership.
700 			 * Controller is not the current owner of the LUN,
701 			 * Fail the path, so that the other path be used.
702 			 */
703 			h->state = RDAC_STATE_PASSIVE;
704 			return SUCCESS;
705 		}
706 		break;
707 	case UNIT_ATTENTION:
708 		if (sense_hdr->asc == 0x29 && sense_hdr->ascq == 0x00)
709 			/*
710 			 * Power On, Reset, or Bus Device Reset, just retry.
711 			 */
712 			return ADD_TO_MLQUEUE;
713 		if (sense_hdr->asc == 0x8b && sense_hdr->ascq == 0x02)
714 			/*
715 			 * Quiescence in progress , just retry.
716 			 */
717 			return ADD_TO_MLQUEUE;
718 		break;
719 	}
720 	/* success just means we do not care what scsi-ml does */
721 	return SCSI_RETURN_NOT_HANDLED;
722 }
723 
724 static int rdac_bus_attach(struct scsi_device *sdev)
725 {
726 	struct rdac_dh_data *h;
727 	int err;
728 	char array_name[ARRAY_LABEL_LEN];
729 	char array_id[UNIQUE_ID_LEN];
730 
731 	h = kzalloc(sizeof(*h) , GFP_KERNEL);
732 	if (!h)
733 		return SCSI_DH_NOMEM;
734 	h->lun = UNINITIALIZED_LUN;
735 	h->state = RDAC_STATE_ACTIVE;
736 
737 	err = get_lun_info(sdev, h, array_name, array_id);
738 	if (err != SCSI_DH_OK)
739 		goto failed;
740 
741 	err = initialize_controller(sdev, h, array_name, array_id);
742 	if (err != SCSI_DH_OK)
743 		goto failed;
744 
745 	err = check_ownership(sdev, h);
746 	if (err != SCSI_DH_OK)
747 		goto clean_ctlr;
748 
749 	err = set_mode_select(sdev, h);
750 	if (err != SCSI_DH_OK)
751 		goto clean_ctlr;
752 
753 	sdev_printk(KERN_NOTICE, sdev,
754 		    "%s: LUN %d (%s) (%s)\n",
755 		    RDAC_NAME, h->lun, mode[(int)h->mode],
756 		    lun_state[(int)h->lun_state]);
757 
758 	sdev->handler_data = h;
759 	return SCSI_DH_OK;
760 
761 clean_ctlr:
762 	spin_lock(&list_lock);
763 	kref_put(&h->ctlr->kref, release_controller);
764 	spin_unlock(&list_lock);
765 
766 failed:
767 	kfree(h);
768 	return err;
769 }
770 
771 static void rdac_bus_detach( struct scsi_device *sdev )
772 {
773 	struct rdac_dh_data *h = sdev->handler_data;
774 
775 	if (h->ctlr && h->ctlr->ms_queued)
776 		flush_workqueue(kmpath_rdacd);
777 
778 	spin_lock(&list_lock);
779 	if (h->ctlr) {
780 		list_del_rcu(&h->node);
781 		kref_put(&h->ctlr->kref, release_controller);
782 	}
783 	spin_unlock(&list_lock);
784 	sdev->handler_data = NULL;
785 	synchronize_rcu();
786 	kfree(h);
787 }
788 
789 static struct scsi_device_handler rdac_dh = {
790 	.name = RDAC_NAME,
791 	.module = THIS_MODULE,
792 	.prep_fn = rdac_prep_fn,
793 	.check_sense = rdac_check_sense,
794 	.attach = rdac_bus_attach,
795 	.detach = rdac_bus_detach,
796 	.activate = rdac_activate,
797 };
798 
799 static int __init rdac_init(void)
800 {
801 	int r;
802 
803 	r = scsi_register_device_handler(&rdac_dh);
804 	if (r != 0) {
805 		printk(KERN_ERR "Failed to register scsi device handler.");
806 		goto done;
807 	}
808 
809 	/*
810 	 * Create workqueue to handle mode selects for rdac
811 	 */
812 	kmpath_rdacd = create_singlethread_workqueue("kmpath_rdacd");
813 	if (!kmpath_rdacd) {
814 		scsi_unregister_device_handler(&rdac_dh);
815 		printk(KERN_ERR "kmpath_rdacd creation failed.\n");
816 
817 		r = -EINVAL;
818 	}
819 done:
820 	return r;
821 }
822 
823 static void __exit rdac_exit(void)
824 {
825 	destroy_workqueue(kmpath_rdacd);
826 	scsi_unregister_device_handler(&rdac_dh);
827 }
828 
829 module_init(rdac_init);
830 module_exit(rdac_exit);
831 
832 MODULE_DESCRIPTION("Multipath LSI/Engenio/NetApp E-Series RDAC driver");
833 MODULE_AUTHOR("Mike Christie, Chandra Seetharaman");
834 MODULE_VERSION("01.00.0000.0000");
835 MODULE_LICENSE("GPL");
836