xref: /openbmc/linux/drivers/scsi/device_handler/scsi_dh_emc.c (revision f15cbe6f1a4b4d9df59142fc8e4abb973302cf44)
1 /*
2  * Target driver for EMC CLARiiON AX/CX-series hardware.
3  * Based on code from Lars Marowsky-Bree <lmb@suse.de>
4  * and Ed Goggin <egoggin@emc.com>.
5  *
6  * Copyright (C) 2006 Red Hat, Inc.  All rights reserved.
7  * Copyright (C) 2006 Mike Christie
8  *
9  * This program is free software; you can redistribute it and/or modify
10  * it under the terms of the GNU General Public License as published by
11  * the Free Software Foundation; either version 2, or (at your option)
12  * any later version.
13  *
14  * This program is distributed in the hope that it will be useful,
15  * but WITHOUT ANY WARRANTY; without even the implied warranty of
16  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
17  * GNU General Public License for more details.
18  *
19  * You should have received a copy of the GNU General Public License
20  * along with this program; see the file COPYING.  If not, write to
21  * the Free Software Foundation, 675 Mass Ave, Cambridge, MA 02139, USA.
22  */
23 #include <scsi/scsi.h>
24 #include <scsi/scsi_eh.h>
25 #include <scsi/scsi_dh.h>
26 #include <scsi/scsi_device.h>
27 
28 #define CLARIION_NAME			"emc"
29 
30 #define CLARIION_TRESPASS_PAGE		0x22
31 #define CLARIION_BUFFER_SIZE		0xFC
32 #define CLARIION_TIMEOUT		(60 * HZ)
33 #define CLARIION_RETRIES		3
34 #define CLARIION_UNBOUND_LU		-1
35 #define CLARIION_SP_A			0
36 #define CLARIION_SP_B			1
37 
38 /* Flags */
39 #define CLARIION_SHORT_TRESPASS		1
40 #define CLARIION_HONOR_RESERVATIONS	2
41 
42 /* LUN states */
43 #define CLARIION_LUN_UNINITIALIZED	-1
44 #define CLARIION_LUN_UNBOUND		0
45 #define CLARIION_LUN_BOUND		1
46 #define CLARIION_LUN_OWNED		2
47 
48 static unsigned char long_trespass[] = {
49 	0, 0, 0, 0, 0, 0, 0, 0,
50 	CLARIION_TRESPASS_PAGE,	/* Page code */
51 	0x09,			/* Page length - 2 */
52 	0x01,			/* Trespass code */
53 	0xff, 0xff,		/* Trespass target */
54 	0, 0, 0, 0, 0, 0	/* Reserved bytes / unknown */
55 };
56 
57 static unsigned char short_trespass[] = {
58 	0, 0, 0, 0,
59 	CLARIION_TRESPASS_PAGE,	/* Page code */
60 	0x02,			/* Page length - 2 */
61 	0x01,			/* Trespass code */
62 	0xff,			/* Trespass target */
63 };
64 
65 static const char * lun_state[] =
66 {
67     "not bound",
68     "bound",
69     "owned",
70 };
71 
72 struct clariion_dh_data {
73 	/*
74 	 * Flags:
75 	 *  CLARIION_SHORT_TRESPASS
76 	 * Use short trespass command (FC-series) or the long version
77 	 * (default for AX/CX CLARiiON arrays).
78 	 *
79 	 *  CLARIION_HONOR_RESERVATIONS
80 	 * Whether or not (default) to honor SCSI reservations when
81 	 * initiating a switch-over.
82 	 */
83 	unsigned flags;
84 	/*
85 	 * I/O buffer for both MODE_SELECT and INQUIRY commands.
86 	 */
87 	char buffer[CLARIION_BUFFER_SIZE];
88 	/*
89 	 * SCSI sense buffer for commands -- assumes serial issuance
90 	 * and completion sequence of all commands for same multipath.
91 	 */
92 	unsigned char sense[SCSI_SENSE_BUFFERSIZE];
93 	unsigned int senselen;
94 	/*
95 	 * LUN state
96 	 */
97 	int lun_state;
98 	/*
99 	 * SP Port number
100 	 */
101 	int port;
102 	/*
103 	 * which SP (A=0,B=1,UNBOUND=-1) is the default SP for this
104 	 * path's mapped LUN
105 	 */
106 	int default_sp;
107 	/*
108 	 * which SP (A=0,B=1,UNBOUND=-1) is the active SP for this
109 	 * path's mapped LUN
110 	 */
111 	int current_sp;
112 };
113 
114 static inline struct clariion_dh_data
115 			*get_clariion_data(struct scsi_device *sdev)
116 {
117 	struct scsi_dh_data *scsi_dh_data = sdev->scsi_dh_data;
118 	BUG_ON(scsi_dh_data == NULL);
119 	return ((struct clariion_dh_data *) scsi_dh_data->buf);
120 }
121 
122 /*
123  * Parse MODE_SELECT cmd reply.
124  */
125 static int trespass_endio(struct scsi_device *sdev, char *sense)
126 {
127 	int err = SCSI_DH_IO;
128 	struct scsi_sense_hdr sshdr;
129 
130 	if (!scsi_normalize_sense(sense, SCSI_SENSE_BUFFERSIZE, &sshdr)) {
131 		sdev_printk(KERN_ERR, sdev, "%s: Found valid sense data 0x%2x, "
132 			    "0x%2x, 0x%2x while sending CLARiiON trespass "
133 			    "command.\n", CLARIION_NAME, sshdr.sense_key,
134 			    sshdr.asc, sshdr.ascq);
135 
136 		if ((sshdr.sense_key == 0x05) && (sshdr.asc == 0x04) &&
137 		     (sshdr.ascq == 0x00)) {
138 			/*
139 			 * Array based copy in progress -- do not send
140 			 * mode_select or copy will be aborted mid-stream.
141 			 */
142 			sdev_printk(KERN_INFO, sdev, "%s: Array Based Copy in "
143 				    "progress while sending CLARiiON trespass "
144 				    "command.\n", CLARIION_NAME);
145 			err = SCSI_DH_DEV_TEMP_BUSY;
146 		} else if ((sshdr.sense_key == 0x02) && (sshdr.asc == 0x04) &&
147 			    (sshdr.ascq == 0x03)) {
148 			/*
149 			 * LUN Not Ready - Manual Intervention Required
150 			 * indicates in-progress ucode upgrade (NDU).
151 			 */
152 			sdev_printk(KERN_INFO, sdev, "%s: Detected in-progress "
153 				    "ucode upgrade NDU operation while sending "
154 				    "CLARiiON trespass command.\n", CLARIION_NAME);
155 			err = SCSI_DH_DEV_TEMP_BUSY;
156 		} else
157 			err = SCSI_DH_DEV_FAILED;
158 	} else {
159 		sdev_printk(KERN_INFO, sdev,
160 			    "%s: failed to send MODE SELECT, no sense available\n",
161 			    CLARIION_NAME);
162 	}
163 	return err;
164 }
165 
166 static int parse_sp_info_reply(struct scsi_device *sdev,
167 			       struct clariion_dh_data *csdev)
168 {
169 	int err = SCSI_DH_OK;
170 
171 	/* check for in-progress ucode upgrade (NDU) */
172 	if (csdev->buffer[48] != 0) {
173 		sdev_printk(KERN_NOTICE, sdev, "%s: Detected in-progress "
174 			    "ucode upgrade NDU operation while finding "
175 			    "current active SP.", CLARIION_NAME);
176 		err = SCSI_DH_DEV_TEMP_BUSY;
177 		goto out;
178 	}
179 	if (csdev->buffer[4] < 0 || csdev->buffer[4] > 2) {
180 		/* Invalid buffer format */
181 		sdev_printk(KERN_NOTICE, sdev,
182 			    "%s: invalid VPD page 0xC0 format\n",
183 			    CLARIION_NAME);
184 		err = SCSI_DH_NOSYS;
185 		goto out;
186 	}
187 	switch (csdev->buffer[28] & 0x0f) {
188 	case 6:
189 		sdev_printk(KERN_NOTICE, sdev,
190 			    "%s: ALUA failover mode detected\n",
191 			    CLARIION_NAME);
192 		break;
193 	case 4:
194 		/* Linux failover */
195 		break;
196 	default:
197 		sdev_printk(KERN_WARNING, sdev,
198 			    "%s: Invalid failover mode %d\n",
199 			    CLARIION_NAME, csdev->buffer[28] & 0x0f);
200 		err = SCSI_DH_NOSYS;
201 		goto out;
202 	}
203 
204 	csdev->default_sp = csdev->buffer[5];
205 	csdev->lun_state = csdev->buffer[4];
206 	csdev->current_sp = csdev->buffer[8];
207 	csdev->port = csdev->buffer[7];
208 
209 out:
210 	return err;
211 }
212 
213 #define emc_default_str "FC (Legacy)"
214 
215 static char * parse_sp_model(struct scsi_device *sdev, unsigned char *buffer)
216 {
217 	unsigned char len = buffer[4] + 5;
218 	char *sp_model = NULL;
219 	unsigned char sp_len, serial_len;
220 
221 	if (len < 160) {
222 		sdev_printk(KERN_WARNING, sdev,
223 			    "%s: Invalid information section length %d\n",
224 			    CLARIION_NAME, len);
225 		/* Check for old FC arrays */
226 		if (!strncmp(buffer + 8, "DGC", 3)) {
227 			/* Old FC array, not supporting extended information */
228 			sp_model = emc_default_str;
229 		}
230 		goto out;
231 	}
232 
233 	/*
234 	 * Parse extended information for SP model number
235 	 */
236 	serial_len = buffer[160];
237 	if (serial_len == 0 || serial_len + 161 > len) {
238 		sdev_printk(KERN_WARNING, sdev,
239 			    "%s: Invalid array serial number length %d\n",
240 			    CLARIION_NAME, serial_len);
241 		goto out;
242 	}
243 	sp_len = buffer[99];
244 	if (sp_len == 0 || serial_len + sp_len + 161 > len) {
245 		sdev_printk(KERN_WARNING, sdev,
246 			    "%s: Invalid model number length %d\n",
247 			    CLARIION_NAME, sp_len);
248 		goto out;
249 	}
250 	sp_model = &buffer[serial_len + 161];
251 	/* Strip whitespace at the end */
252 	while (sp_len > 1 && sp_model[sp_len - 1] == ' ')
253 		sp_len--;
254 
255 	sp_model[sp_len] = '\0';
256 
257 out:
258 	return sp_model;
259 }
260 
261 /*
262  * Get block request for REQ_BLOCK_PC command issued to path.  Currently
263  * limited to MODE_SELECT (trespass) and INQUIRY (VPD page 0xC0) commands.
264  *
265  * Uses data and sense buffers in hardware handler context structure and
266  * assumes serial servicing of commands, both issuance and completion.
267  */
268 static struct request *get_req(struct scsi_device *sdev, int cmd,
269 				unsigned char *buffer)
270 {
271 	struct request *rq;
272 	int len = 0;
273 
274 	rq = blk_get_request(sdev->request_queue,
275 			(cmd == MODE_SELECT) ? WRITE : READ, GFP_NOIO);
276 	if (!rq) {
277 		sdev_printk(KERN_INFO, sdev, "get_req: blk_get_request failed");
278 		return NULL;
279 	}
280 
281 	memset(rq->cmd, 0, BLK_MAX_CDB);
282 	rq->cmd_len = COMMAND_SIZE(cmd);
283 	rq->cmd[0] = cmd;
284 
285 	switch (cmd) {
286 	case MODE_SELECT:
287 		len = sizeof(short_trespass);
288 		rq->cmd_flags |= REQ_RW;
289 		rq->cmd[1] = 0x10;
290 		break;
291 	case MODE_SELECT_10:
292 		len = sizeof(long_trespass);
293 		rq->cmd_flags |= REQ_RW;
294 		rq->cmd[1] = 0x10;
295 		break;
296 	case INQUIRY:
297 		len = CLARIION_BUFFER_SIZE;
298 		memset(buffer, 0, len);
299 		break;
300 	default:
301 		BUG_ON(1);
302 		break;
303 	}
304 
305 	rq->cmd[4] = len;
306 	rq->cmd_type = REQ_TYPE_BLOCK_PC;
307 	rq->cmd_flags |= REQ_FAILFAST;
308 	rq->timeout = CLARIION_TIMEOUT;
309 	rq->retries = CLARIION_RETRIES;
310 
311 	if (blk_rq_map_kern(rq->q, rq, buffer, len, GFP_NOIO)) {
312 		blk_put_request(rq);
313 		return NULL;
314 	}
315 
316 	return rq;
317 }
318 
319 static int send_inquiry_cmd(struct scsi_device *sdev, int page,
320 			    struct clariion_dh_data *csdev)
321 {
322 	struct request *rq = get_req(sdev, INQUIRY, csdev->buffer);
323 	int err;
324 
325 	if (!rq)
326 		return SCSI_DH_RES_TEMP_UNAVAIL;
327 
328 	rq->sense = csdev->sense;
329 	memset(rq->sense, 0, SCSI_SENSE_BUFFERSIZE);
330 	rq->sense_len = csdev->senselen = 0;
331 
332 	rq->cmd[0] = INQUIRY;
333 	if (page != 0) {
334 		rq->cmd[1] = 1;
335 		rq->cmd[2] = page;
336 	}
337 	err = blk_execute_rq(sdev->request_queue, NULL, rq, 1);
338 	if (err == -EIO) {
339 		sdev_printk(KERN_INFO, sdev,
340 			    "%s: failed to send %s INQUIRY: %x\n",
341 			    CLARIION_NAME, page?"EVPD":"standard",
342 			    rq->errors);
343 		csdev->senselen = rq->sense_len;
344 		err = SCSI_DH_IO;
345 	}
346 
347 	blk_put_request(rq);
348 
349 	return err;
350 }
351 
352 static int send_trespass_cmd(struct scsi_device *sdev,
353 			    struct clariion_dh_data *csdev)
354 {
355 	struct request *rq;
356 	unsigned char *page22;
357 	int err, len, cmd;
358 
359 	if (csdev->flags & CLARIION_SHORT_TRESPASS) {
360 		page22 = short_trespass;
361 		if (!(csdev->flags & CLARIION_HONOR_RESERVATIONS))
362 			/* Set Honor Reservations bit */
363 			page22[6] |= 0x80;
364 		len = sizeof(short_trespass);
365 		cmd = MODE_SELECT;
366 	} else {
367 		page22 = long_trespass;
368 		if (!(csdev->flags & CLARIION_HONOR_RESERVATIONS))
369 			/* Set Honor Reservations bit */
370 			page22[10] |= 0x80;
371 		len = sizeof(long_trespass);
372 		cmd = MODE_SELECT_10;
373 	}
374 	BUG_ON((len > CLARIION_BUFFER_SIZE));
375 	memcpy(csdev->buffer, page22, len);
376 
377 	rq = get_req(sdev, cmd, csdev->buffer);
378 	if (!rq)
379 		return SCSI_DH_RES_TEMP_UNAVAIL;
380 
381 	rq->sense = csdev->sense;
382 	memset(rq->sense, 0, SCSI_SENSE_BUFFERSIZE);
383 	rq->sense_len = csdev->senselen = 0;
384 
385 	err = blk_execute_rq(sdev->request_queue, NULL, rq, 1);
386 	if (err == -EIO) {
387 		if (rq->sense_len) {
388 			err = trespass_endio(sdev, csdev->sense);
389 		} else {
390 			sdev_printk(KERN_INFO, sdev,
391 				    "%s: failed to send MODE SELECT: %x\n",
392 				    CLARIION_NAME, rq->errors);
393 		}
394 	}
395 
396 	blk_put_request(rq);
397 
398 	return err;
399 }
400 
401 static int clariion_check_sense(struct scsi_device *sdev,
402 				struct scsi_sense_hdr *sense_hdr)
403 {
404 	switch (sense_hdr->sense_key) {
405 	case NOT_READY:
406 		if (sense_hdr->asc == 0x04 && sense_hdr->ascq == 0x03)
407 			/*
408 			 * LUN Not Ready - Manual Intervention Required
409 			 * indicates this is a passive path.
410 			 *
411 			 * FIXME: However, if this is seen and EVPD C0
412 			 * indicates that this is due to a NDU in
413 			 * progress, we should set FAIL_PATH too.
414 			 * This indicates we might have to do a SCSI
415 			 * inquiry in the end_io path. Ugh.
416 			 *
417 			 * Can return FAILED only when we want the error
418 			 * recovery process to kick in.
419 			 */
420 			return SUCCESS;
421 		break;
422 	case ILLEGAL_REQUEST:
423 		if (sense_hdr->asc == 0x25 && sense_hdr->ascq == 0x01)
424 			/*
425 			 * An array based copy is in progress. Do not
426 			 * fail the path, do not bypass to another PG,
427 			 * do not retry. Fail the IO immediately.
428 			 * (Actually this is the same conclusion as in
429 			 * the default handler, but lets make sure.)
430 			 *
431 			 * Can return FAILED only when we want the error
432 			 * recovery process to kick in.
433 			 */
434 			return SUCCESS;
435 		break;
436 	case UNIT_ATTENTION:
437 		if (sense_hdr->asc == 0x29 && sense_hdr->ascq == 0x00)
438 			/*
439 			 * Unit Attention Code. This is the first IO
440 			 * to the new path, so just retry.
441 			 */
442 			return NEEDS_RETRY;
443 		break;
444 	}
445 
446 	return SCSI_RETURN_NOT_HANDLED;
447 }
448 
449 static int clariion_prep_fn(struct scsi_device *sdev, struct request *req)
450 {
451 	struct clariion_dh_data *h = get_clariion_data(sdev);
452 	int ret = BLKPREP_OK;
453 
454 	if (h->lun_state != CLARIION_LUN_OWNED) {
455 		ret = BLKPREP_KILL;
456 		req->cmd_flags |= REQ_QUIET;
457 	}
458 	return ret;
459 
460 }
461 
462 static int clariion_std_inquiry(struct scsi_device *sdev,
463 				struct clariion_dh_data *csdev)
464 {
465 	int err;
466 	char *sp_model;
467 
468 	err = send_inquiry_cmd(sdev, 0, csdev);
469 	if (err != SCSI_DH_OK && csdev->senselen) {
470 		struct scsi_sense_hdr sshdr;
471 
472 		if (scsi_normalize_sense(csdev->sense, SCSI_SENSE_BUFFERSIZE,
473 					 &sshdr)) {
474 			sdev_printk(KERN_ERR, sdev, "%s: INQUIRY sense code "
475 				    "%02x/%02x/%02x\n", CLARIION_NAME,
476 				    sshdr.sense_key, sshdr.asc, sshdr.ascq);
477 		}
478 		err = SCSI_DH_IO;
479 		goto out;
480 	}
481 
482 	sp_model = parse_sp_model(sdev, csdev->buffer);
483 	if (!sp_model) {
484 		err = SCSI_DH_DEV_UNSUPP;
485 		goto out;
486 	}
487 
488 	/*
489 	 * FC Series arrays do not support long trespass
490 	 */
491 	if (!strlen(sp_model) || !strncmp(sp_model, "FC",2))
492 		csdev->flags |= CLARIION_SHORT_TRESPASS;
493 
494 	sdev_printk(KERN_INFO, sdev,
495 		    "%s: detected Clariion %s, flags %x\n",
496 		    CLARIION_NAME, sp_model, csdev->flags);
497 out:
498 	return err;
499 }
500 
501 static int clariion_send_inquiry(struct scsi_device *sdev,
502 				 struct clariion_dh_data *csdev)
503 {
504 	int err, retry = CLARIION_RETRIES;
505 
506 retry:
507 	err = send_inquiry_cmd(sdev, 0xC0, csdev);
508 	if (err != SCSI_DH_OK && csdev->senselen) {
509 		struct scsi_sense_hdr sshdr;
510 
511 		err = scsi_normalize_sense(csdev->sense, SCSI_SENSE_BUFFERSIZE,
512 					   &sshdr);
513 		if (!err)
514 			return SCSI_DH_IO;
515 
516 		err = clariion_check_sense(sdev, &sshdr);
517 		if (retry > 0 && err == NEEDS_RETRY) {
518 			retry--;
519 			goto retry;
520 		}
521 		sdev_printk(KERN_ERR, sdev, "%s: INQUIRY sense code "
522 			    "%02x/%02x/%02x\n", CLARIION_NAME,
523 			      sshdr.sense_key, sshdr.asc, sshdr.ascq);
524 		err = SCSI_DH_IO;
525 	} else {
526 		err = parse_sp_info_reply(sdev, csdev);
527 	}
528 	return err;
529 }
530 
531 static int clariion_activate(struct scsi_device *sdev)
532 {
533 	struct clariion_dh_data *csdev = get_clariion_data(sdev);
534 	int result;
535 
536 	result = clariion_send_inquiry(sdev, csdev);
537 	if (result != SCSI_DH_OK)
538 		goto done;
539 
540 	if (csdev->lun_state == CLARIION_LUN_OWNED)
541 		goto done;
542 
543 	result = send_trespass_cmd(sdev, csdev);
544 	if (result != SCSI_DH_OK)
545 		goto done;
546 	sdev_printk(KERN_INFO, sdev,"%s: %s trespass command sent\n",
547 		    CLARIION_NAME,
548 		    csdev->flags&CLARIION_SHORT_TRESPASS?"short":"long" );
549 
550 	/* Update status */
551 	result = clariion_send_inquiry(sdev, csdev);
552 	if (result != SCSI_DH_OK)
553 		goto done;
554 
555 done:
556 	sdev_printk(KERN_INFO, sdev,
557 		    "%s: at SP %c Port %d (%s, default SP %c)\n",
558 		    CLARIION_NAME, csdev->current_sp + 'A',
559 		    csdev->port, lun_state[csdev->lun_state],
560 		    csdev->default_sp + 'A');
561 
562 	return result;
563 }
564 
565 const struct scsi_dh_devlist clariion_dev_list[] = {
566 	{"DGC", "RAID"},
567 	{"DGC", "DISK"},
568 	{"DGC", "VRAID"},
569 	{NULL, NULL},
570 };
571 
572 static int clariion_bus_attach(struct scsi_device *sdev);
573 static void clariion_bus_detach(struct scsi_device *sdev);
574 
575 static struct scsi_device_handler clariion_dh = {
576 	.name		= CLARIION_NAME,
577 	.module		= THIS_MODULE,
578 	.devlist	= clariion_dev_list,
579 	.attach		= clariion_bus_attach,
580 	.detach		= clariion_bus_detach,
581 	.check_sense	= clariion_check_sense,
582 	.activate	= clariion_activate,
583 	.prep_fn	= clariion_prep_fn,
584 };
585 
586 /*
587  * TODO: need some interface so we can set trespass values
588  */
589 static int clariion_bus_attach(struct scsi_device *sdev)
590 {
591 	struct scsi_dh_data *scsi_dh_data;
592 	struct clariion_dh_data *h;
593 	unsigned long flags;
594 	int err;
595 
596 	scsi_dh_data = kzalloc(sizeof(struct scsi_device_handler *)
597 			       + sizeof(*h) , GFP_KERNEL);
598 	if (!scsi_dh_data) {
599 		sdev_printk(KERN_ERR, sdev, "%s: Attach failed\n",
600 			    CLARIION_NAME);
601 		return -ENOMEM;
602 	}
603 
604 	scsi_dh_data->scsi_dh = &clariion_dh;
605 	h = (struct clariion_dh_data *) scsi_dh_data->buf;
606 	h->lun_state = CLARIION_LUN_UNINITIALIZED;
607 	h->default_sp = CLARIION_UNBOUND_LU;
608 	h->current_sp = CLARIION_UNBOUND_LU;
609 
610 	err = clariion_std_inquiry(sdev, h);
611 	if (err != SCSI_DH_OK)
612 		goto failed;
613 
614 	err = clariion_send_inquiry(sdev, h);
615 	if (err != SCSI_DH_OK)
616 		goto failed;
617 
618 	if (!try_module_get(THIS_MODULE))
619 		goto failed;
620 
621 	spin_lock_irqsave(sdev->request_queue->queue_lock, flags);
622 	sdev->scsi_dh_data = scsi_dh_data;
623 	spin_unlock_irqrestore(sdev->request_queue->queue_lock, flags);
624 
625 	sdev_printk(KERN_INFO, sdev,
626 		    "%s: connected to SP %c Port %d (%s, default SP %c)\n",
627 		    CLARIION_NAME, h->current_sp + 'A',
628 		    h->port, lun_state[h->lun_state],
629 		    h->default_sp + 'A');
630 
631 	return 0;
632 
633 failed:
634 	kfree(scsi_dh_data);
635 	sdev_printk(KERN_ERR, sdev, "%s: not attached\n",
636 		    CLARIION_NAME);
637 	return -EINVAL;
638 }
639 
640 static void clariion_bus_detach(struct scsi_device *sdev)
641 {
642 	struct scsi_dh_data *scsi_dh_data;
643 	unsigned long flags;
644 
645 	spin_lock_irqsave(sdev->request_queue->queue_lock, flags);
646 	scsi_dh_data = sdev->scsi_dh_data;
647 	sdev->scsi_dh_data = NULL;
648 	spin_unlock_irqrestore(sdev->request_queue->queue_lock, flags);
649 
650 	sdev_printk(KERN_NOTICE, sdev, "%s: Detached\n",
651 		    CLARIION_NAME);
652 
653 	kfree(scsi_dh_data);
654 	module_put(THIS_MODULE);
655 }
656 
657 static int __init clariion_init(void)
658 {
659 	int r;
660 
661 	r = scsi_register_device_handler(&clariion_dh);
662 	if (r != 0)
663 		printk(KERN_ERR "%s: Failed to register scsi device handler.",
664 			CLARIION_NAME);
665 	return r;
666 }
667 
668 static void __exit clariion_exit(void)
669 {
670 	scsi_unregister_device_handler(&clariion_dh);
671 }
672 
673 module_init(clariion_init);
674 module_exit(clariion_exit);
675 
676 MODULE_DESCRIPTION("EMC CX/AX/FC-family driver");
677 MODULE_AUTHOR("Mike Christie <michaelc@cs.wisc.edu>, Chandra Seetharaman <sekharan@us.ibm.com>");
678 MODULE_LICENSE("GPL");
679