xref: /openbmc/linux/drivers/scsi/scsi_scan.c (revision 22246614)
1 /*
2  * scsi_scan.c
3  *
4  * Copyright (C) 2000 Eric Youngdale,
5  * Copyright (C) 2002 Patrick Mansfield
6  *
7  * The general scanning/probing algorithm is as follows, exceptions are
8  * made to it depending on device specific flags, compilation options, and
9  * global variable (boot or module load time) settings.
10  *
11  * A specific LUN is scanned via an INQUIRY command; if the LUN has a
12  * device attached, a scsi_device is allocated and setup for it.
13  *
14  * For every id of every channel on the given host:
15  *
16  * 	Scan LUN 0; if the target responds to LUN 0 (even if there is no
17  * 	device or storage attached to LUN 0):
18  *
19  * 		If LUN 0 has a device attached, allocate and setup a
20  * 		scsi_device for it.
21  *
22  * 		If target is SCSI-3 or up, issue a REPORT LUN, and scan
23  * 		all of the LUNs returned by the REPORT LUN; else,
24  * 		sequentially scan LUNs up until some maximum is reached,
25  * 		or a LUN is seen that cannot have a device attached to it.
26  */
27 
28 #include <linux/module.h>
29 #include <linux/moduleparam.h>
30 #include <linux/init.h>
31 #include <linux/blkdev.h>
32 #include <linux/delay.h>
33 #include <linux/kthread.h>
34 #include <linux/spinlock.h>
35 
36 #include <scsi/scsi.h>
37 #include <scsi/scsi_cmnd.h>
38 #include <scsi/scsi_device.h>
39 #include <scsi/scsi_driver.h>
40 #include <scsi/scsi_devinfo.h>
41 #include <scsi/scsi_host.h>
42 #include <scsi/scsi_transport.h>
43 #include <scsi/scsi_eh.h>
44 
45 #include "scsi_priv.h"
46 #include "scsi_logging.h"
47 
48 #define ALLOC_FAILURE_MSG	KERN_ERR "%s: Allocation failure during" \
49 	" SCSI scanning, some SCSI devices might not be configured\n"
50 
51 /*
52  * Default timeout
53  */
54 #define SCSI_TIMEOUT (2*HZ)
55 
56 /*
57  * Prefix values for the SCSI id's (stored in sysfs name field)
58  */
59 #define SCSI_UID_SER_NUM 'S'
60 #define SCSI_UID_UNKNOWN 'Z'
61 
62 /*
63  * Return values of some of the scanning functions.
64  *
65  * SCSI_SCAN_NO_RESPONSE: no valid response received from the target, this
66  * includes allocation or general failures preventing IO from being sent.
67  *
68  * SCSI_SCAN_TARGET_PRESENT: target responded, but no device is available
69  * on the given LUN.
70  *
71  * SCSI_SCAN_LUN_PRESENT: target responded, and a device is available on a
72  * given LUN.
73  */
74 #define SCSI_SCAN_NO_RESPONSE		0
75 #define SCSI_SCAN_TARGET_PRESENT	1
76 #define SCSI_SCAN_LUN_PRESENT		2
77 
78 static const char *scsi_null_device_strs = "nullnullnullnull";
79 
80 #define MAX_SCSI_LUNS	512
81 
82 #ifdef CONFIG_SCSI_MULTI_LUN
83 static unsigned int max_scsi_luns = MAX_SCSI_LUNS;
84 #else
85 static unsigned int max_scsi_luns = 1;
86 #endif
87 
88 module_param_named(max_luns, max_scsi_luns, uint, S_IRUGO|S_IWUSR);
89 MODULE_PARM_DESC(max_luns,
90 		 "last scsi LUN (should be between 1 and 2^32-1)");
91 
92 #ifdef CONFIG_SCSI_SCAN_ASYNC
93 #define SCSI_SCAN_TYPE_DEFAULT "async"
94 #else
95 #define SCSI_SCAN_TYPE_DEFAULT "sync"
96 #endif
97 
98 static char scsi_scan_type[6] = SCSI_SCAN_TYPE_DEFAULT;
99 
100 module_param_string(scan, scsi_scan_type, sizeof(scsi_scan_type), S_IRUGO);
101 MODULE_PARM_DESC(scan, "sync, async or none");
102 
103 /*
104  * max_scsi_report_luns: the maximum number of LUNS that will be
105  * returned from the REPORT LUNS command. 8 times this value must
106  * be allocated. In theory this could be up to an 8 byte value, but
107  * in practice, the maximum number of LUNs suppored by any device
108  * is about 16k.
109  */
110 static unsigned int max_scsi_report_luns = 511;
111 
112 module_param_named(max_report_luns, max_scsi_report_luns, uint, S_IRUGO|S_IWUSR);
113 MODULE_PARM_DESC(max_report_luns,
114 		 "REPORT LUNS maximum number of LUNS received (should be"
115 		 " between 1 and 16384)");
116 
117 static unsigned int scsi_inq_timeout = SCSI_TIMEOUT/HZ+3;
118 
119 module_param_named(inq_timeout, scsi_inq_timeout, uint, S_IRUGO|S_IWUSR);
120 MODULE_PARM_DESC(inq_timeout,
121 		 "Timeout (in seconds) waiting for devices to answer INQUIRY."
122 		 " Default is 5. Some non-compliant devices need more.");
123 
124 /* This lock protects only this list */
125 static DEFINE_SPINLOCK(async_scan_lock);
126 static LIST_HEAD(scanning_hosts);
127 
128 struct async_scan_data {
129 	struct list_head list;
130 	struct Scsi_Host *shost;
131 	struct completion prev_finished;
132 };
133 
134 /**
135  * scsi_complete_async_scans - Wait for asynchronous scans to complete
136  *
137  * When this function returns, any host which started scanning before
138  * this function was called will have finished its scan.  Hosts which
139  * started scanning after this function was called may or may not have
140  * finished.
141  */
142 int scsi_complete_async_scans(void)
143 {
144 	struct async_scan_data *data;
145 
146 	do {
147 		if (list_empty(&scanning_hosts))
148 			return 0;
149 		/* If we can't get memory immediately, that's OK.  Just
150 		 * sleep a little.  Even if we never get memory, the async
151 		 * scans will finish eventually.
152 		 */
153 		data = kmalloc(sizeof(*data), GFP_KERNEL);
154 		if (!data)
155 			msleep(1);
156 	} while (!data);
157 
158 	data->shost = NULL;
159 	init_completion(&data->prev_finished);
160 
161 	spin_lock(&async_scan_lock);
162 	/* Check that there's still somebody else on the list */
163 	if (list_empty(&scanning_hosts))
164 		goto done;
165 	list_add_tail(&data->list, &scanning_hosts);
166 	spin_unlock(&async_scan_lock);
167 
168 	printk(KERN_INFO "scsi: waiting for bus probes to complete ...\n");
169 	wait_for_completion(&data->prev_finished);
170 
171 	spin_lock(&async_scan_lock);
172 	list_del(&data->list);
173 	if (!list_empty(&scanning_hosts)) {
174 		struct async_scan_data *next = list_entry(scanning_hosts.next,
175 				struct async_scan_data, list);
176 		complete(&next->prev_finished);
177 	}
178  done:
179 	spin_unlock(&async_scan_lock);
180 
181 	kfree(data);
182 	return 0;
183 }
184 
185 /* Only exported for the benefit of scsi_wait_scan */
186 EXPORT_SYMBOL_GPL(scsi_complete_async_scans);
187 
188 #ifndef MODULE
189 /*
190  * For async scanning we need to wait for all the scans to complete before
191  * trying to mount the root fs.  Otherwise non-modular drivers may not be ready
192  * yet.
193  */
194 late_initcall(scsi_complete_async_scans);
195 #endif
196 
197 /**
198  * scsi_unlock_floptical - unlock device via a special MODE SENSE command
199  * @sdev:	scsi device to send command to
200  * @result:	area to store the result of the MODE SENSE
201  *
202  * Description:
203  *     Send a vendor specific MODE SENSE (not a MODE SELECT) command.
204  *     Called for BLIST_KEY devices.
205  **/
206 static void scsi_unlock_floptical(struct scsi_device *sdev,
207 				  unsigned char *result)
208 {
209 	unsigned char scsi_cmd[MAX_COMMAND_SIZE];
210 
211 	printk(KERN_NOTICE "scsi: unlocking floptical drive\n");
212 	scsi_cmd[0] = MODE_SENSE;
213 	scsi_cmd[1] = 0;
214 	scsi_cmd[2] = 0x2e;
215 	scsi_cmd[3] = 0;
216 	scsi_cmd[4] = 0x2a;     /* size */
217 	scsi_cmd[5] = 0;
218 	scsi_execute_req(sdev, scsi_cmd, DMA_FROM_DEVICE, result, 0x2a, NULL,
219 			 SCSI_TIMEOUT, 3);
220 }
221 
222 /**
223  * scsi_alloc_sdev - allocate and setup a scsi_Device
224  * @starget: which target to allocate a &scsi_device for
225  * @lun: which lun
226  * @hostdata: usually NULL and set by ->slave_alloc instead
227  *
228  * Description:
229  *     Allocate, initialize for io, and return a pointer to a scsi_Device.
230  *     Stores the @shost, @channel, @id, and @lun in the scsi_Device, and
231  *     adds scsi_Device to the appropriate list.
232  *
233  * Return value:
234  *     scsi_Device pointer, or NULL on failure.
235  **/
236 static struct scsi_device *scsi_alloc_sdev(struct scsi_target *starget,
237 					   unsigned int lun, void *hostdata)
238 {
239 	struct scsi_device *sdev;
240 	int display_failure_msg = 1, ret;
241 	struct Scsi_Host *shost = dev_to_shost(starget->dev.parent);
242 	extern void scsi_evt_thread(struct work_struct *work);
243 
244 	sdev = kzalloc(sizeof(*sdev) + shost->transportt->device_size,
245 		       GFP_ATOMIC);
246 	if (!sdev)
247 		goto out;
248 
249 	sdev->vendor = scsi_null_device_strs;
250 	sdev->model = scsi_null_device_strs;
251 	sdev->rev = scsi_null_device_strs;
252 	sdev->host = shost;
253 	sdev->id = starget->id;
254 	sdev->lun = lun;
255 	sdev->channel = starget->channel;
256 	sdev->sdev_state = SDEV_CREATED;
257 	INIT_LIST_HEAD(&sdev->siblings);
258 	INIT_LIST_HEAD(&sdev->same_target_siblings);
259 	INIT_LIST_HEAD(&sdev->cmd_list);
260 	INIT_LIST_HEAD(&sdev->starved_entry);
261 	INIT_LIST_HEAD(&sdev->event_list);
262 	spin_lock_init(&sdev->list_lock);
263 	INIT_WORK(&sdev->event_work, scsi_evt_thread);
264 
265 	sdev->sdev_gendev.parent = get_device(&starget->dev);
266 	sdev->sdev_target = starget;
267 
268 	/* usually NULL and set by ->slave_alloc instead */
269 	sdev->hostdata = hostdata;
270 
271 	/* if the device needs this changing, it may do so in the
272 	 * slave_configure function */
273 	sdev->max_device_blocked = SCSI_DEFAULT_DEVICE_BLOCKED;
274 
275 	/*
276 	 * Some low level driver could use device->type
277 	 */
278 	sdev->type = -1;
279 
280 	/*
281 	 * Assume that the device will have handshaking problems,
282 	 * and then fix this field later if it turns out it
283 	 * doesn't
284 	 */
285 	sdev->borken = 1;
286 
287 	sdev->request_queue = scsi_alloc_queue(sdev);
288 	if (!sdev->request_queue) {
289 		/* release fn is set up in scsi_sysfs_device_initialise, so
290 		 * have to free and put manually here */
291 		put_device(&starget->dev);
292 		kfree(sdev);
293 		goto out;
294 	}
295 
296 	sdev->request_queue->queuedata = sdev;
297 	scsi_adjust_queue_depth(sdev, 0, sdev->host->cmd_per_lun);
298 
299 	scsi_sysfs_device_initialize(sdev);
300 
301 	if (shost->hostt->slave_alloc) {
302 		ret = shost->hostt->slave_alloc(sdev);
303 		if (ret) {
304 			/*
305 			 * if LLDD reports slave not present, don't clutter
306 			 * console with alloc failure messages
307 			 */
308 			if (ret == -ENXIO)
309 				display_failure_msg = 0;
310 			goto out_device_destroy;
311 		}
312 	}
313 
314 	return sdev;
315 
316 out_device_destroy:
317 	transport_destroy_device(&sdev->sdev_gendev);
318 	put_device(&sdev->sdev_gendev);
319 out:
320 	if (display_failure_msg)
321 		printk(ALLOC_FAILURE_MSG, __FUNCTION__);
322 	return NULL;
323 }
324 
325 static void scsi_target_destroy(struct scsi_target *starget)
326 {
327 	struct device *dev = &starget->dev;
328 	struct Scsi_Host *shost = dev_to_shost(dev->parent);
329 	unsigned long flags;
330 
331 	transport_destroy_device(dev);
332 	spin_lock_irqsave(shost->host_lock, flags);
333 	if (shost->hostt->target_destroy)
334 		shost->hostt->target_destroy(starget);
335 	list_del_init(&starget->siblings);
336 	spin_unlock_irqrestore(shost->host_lock, flags);
337 	put_device(dev);
338 }
339 
340 static void scsi_target_dev_release(struct device *dev)
341 {
342 	struct device *parent = dev->parent;
343 	struct scsi_target *starget = to_scsi_target(dev);
344 
345 	kfree(starget);
346 	put_device(parent);
347 }
348 
349 struct device_type scsi_target_type = {
350 	.name =		"scsi_target",
351 	.release =	scsi_target_dev_release,
352 };
353 
354 int scsi_is_target_device(const struct device *dev)
355 {
356 	return dev->type == &scsi_target_type;
357 }
358 EXPORT_SYMBOL(scsi_is_target_device);
359 
360 static struct scsi_target *__scsi_find_target(struct device *parent,
361 					      int channel, uint id)
362 {
363 	struct scsi_target *starget, *found_starget = NULL;
364 	struct Scsi_Host *shost = dev_to_shost(parent);
365 	/*
366 	 * Search for an existing target for this sdev.
367 	 */
368 	list_for_each_entry(starget, &shost->__targets, siblings) {
369 		if (starget->id == id &&
370 		    starget->channel == channel) {
371 			found_starget = starget;
372 			break;
373 		}
374 	}
375 	if (found_starget)
376 		get_device(&found_starget->dev);
377 
378 	return found_starget;
379 }
380 
381 /**
382  * scsi_alloc_target - allocate a new or find an existing target
383  * @parent:	parent of the target (need not be a scsi host)
384  * @channel:	target channel number (zero if no channels)
385  * @id:		target id number
386  *
387  * Return an existing target if one exists, provided it hasn't already
388  * gone into STARGET_DEL state, otherwise allocate a new target.
389  *
390  * The target is returned with an incremented reference, so the caller
391  * is responsible for both reaping and doing a last put
392  */
393 static struct scsi_target *scsi_alloc_target(struct device *parent,
394 					     int channel, uint id)
395 {
396 	struct Scsi_Host *shost = dev_to_shost(parent);
397 	struct device *dev = NULL;
398 	unsigned long flags;
399 	const int size = sizeof(struct scsi_target)
400 		+ shost->transportt->target_size;
401 	struct scsi_target *starget;
402 	struct scsi_target *found_target;
403 	int error;
404 
405 	starget = kzalloc(size, GFP_KERNEL);
406 	if (!starget) {
407 		printk(KERN_ERR "%s: allocation failure\n", __FUNCTION__);
408 		return NULL;
409 	}
410 	dev = &starget->dev;
411 	device_initialize(dev);
412 	starget->reap_ref = 1;
413 	dev->parent = get_device(parent);
414 	sprintf(dev->bus_id, "target%d:%d:%d",
415 		shost->host_no, channel, id);
416 #ifndef CONFIG_SYSFS_DEPRECATED
417 	dev->bus = &scsi_bus_type;
418 #endif
419 	dev->type = &scsi_target_type;
420 	starget->id = id;
421 	starget->channel = channel;
422 	INIT_LIST_HEAD(&starget->siblings);
423 	INIT_LIST_HEAD(&starget->devices);
424 	starget->state = STARGET_CREATED;
425 	starget->scsi_level = SCSI_2;
426  retry:
427 	spin_lock_irqsave(shost->host_lock, flags);
428 
429 	found_target = __scsi_find_target(parent, channel, id);
430 	if (found_target)
431 		goto found;
432 
433 	list_add_tail(&starget->siblings, &shost->__targets);
434 	spin_unlock_irqrestore(shost->host_lock, flags);
435 	/* allocate and add */
436 	transport_setup_device(dev);
437 	if (shost->hostt->target_alloc) {
438 		error = shost->hostt->target_alloc(starget);
439 
440 		if(error) {
441 			dev_printk(KERN_ERR, dev, "target allocation failed, error %d\n", error);
442 			/* don't want scsi_target_reap to do the final
443 			 * put because it will be under the host lock */
444 			scsi_target_destroy(starget);
445 			return NULL;
446 		}
447 	}
448 	get_device(dev);
449 
450 	return starget;
451 
452  found:
453 	found_target->reap_ref++;
454 	spin_unlock_irqrestore(shost->host_lock, flags);
455 	if (found_target->state != STARGET_DEL) {
456 		put_device(parent);
457 		kfree(starget);
458 		return found_target;
459 	}
460 	/* Unfortunately, we found a dying target; need to
461 	 * wait until it's dead before we can get a new one */
462 	put_device(&found_target->dev);
463 	flush_scheduled_work();
464 	goto retry;
465 }
466 
467 static void scsi_target_reap_usercontext(struct work_struct *work)
468 {
469 	struct scsi_target *starget =
470 		container_of(work, struct scsi_target, ew.work);
471 
472 	transport_remove_device(&starget->dev);
473 	device_del(&starget->dev);
474 	scsi_target_destroy(starget);
475 }
476 
477 /**
478  * scsi_target_reap - check to see if target is in use and destroy if not
479  * @starget: target to be checked
480  *
481  * This is used after removing a LUN or doing a last put of the target
482  * it checks atomically that nothing is using the target and removes
483  * it if so.
484  */
485 void scsi_target_reap(struct scsi_target *starget)
486 {
487 	struct Scsi_Host *shost = dev_to_shost(starget->dev.parent);
488 	unsigned long flags;
489 	enum scsi_target_state state;
490 	int empty;
491 
492 	spin_lock_irqsave(shost->host_lock, flags);
493 	state = starget->state;
494 	empty = --starget->reap_ref == 0 &&
495 		list_empty(&starget->devices) ? 1 : 0;
496 	spin_unlock_irqrestore(shost->host_lock, flags);
497 
498 	if (!empty)
499 		return;
500 
501 	BUG_ON(state == STARGET_DEL);
502 	starget->state = STARGET_DEL;
503 	if (state == STARGET_CREATED)
504 		scsi_target_destroy(starget);
505 	else
506 		execute_in_process_context(scsi_target_reap_usercontext,
507 					   &starget->ew);
508 }
509 
510 /**
511  * sanitize_inquiry_string - remove non-graphical chars from an INQUIRY result string
512  * @s: INQUIRY result string to sanitize
513  * @len: length of the string
514  *
515  * Description:
516  *	The SCSI spec says that INQUIRY vendor, product, and revision
517  *	strings must consist entirely of graphic ASCII characters,
518  *	padded on the right with spaces.  Since not all devices obey
519  *	this rule, we will replace non-graphic or non-ASCII characters
520  *	with spaces.  Exception: a NUL character is interpreted as a
521  *	string terminator, so all the following characters are set to
522  *	spaces.
523  **/
524 static void sanitize_inquiry_string(unsigned char *s, int len)
525 {
526 	int terminated = 0;
527 
528 	for (; len > 0; (--len, ++s)) {
529 		if (*s == 0)
530 			terminated = 1;
531 		if (terminated || *s < 0x20 || *s > 0x7e)
532 			*s = ' ';
533 	}
534 }
535 
536 /**
537  * scsi_probe_lun - probe a single LUN using a SCSI INQUIRY
538  * @sdev:	scsi_device to probe
539  * @inq_result:	area to store the INQUIRY result
540  * @result_len: len of inq_result
541  * @bflags:	store any bflags found here
542  *
543  * Description:
544  *     Probe the lun associated with @req using a standard SCSI INQUIRY;
545  *
546  *     If the INQUIRY is successful, zero is returned and the
547  *     INQUIRY data is in @inq_result; the scsi_level and INQUIRY length
548  *     are copied to the scsi_device any flags value is stored in *@bflags.
549  **/
550 static int scsi_probe_lun(struct scsi_device *sdev, unsigned char *inq_result,
551 			  int result_len, int *bflags)
552 {
553 	unsigned char scsi_cmd[MAX_COMMAND_SIZE];
554 	int first_inquiry_len, try_inquiry_len, next_inquiry_len;
555 	int response_len = 0;
556 	int pass, count, result;
557 	struct scsi_sense_hdr sshdr;
558 
559 	*bflags = 0;
560 
561 	/* Perform up to 3 passes.  The first pass uses a conservative
562 	 * transfer length of 36 unless sdev->inquiry_len specifies a
563 	 * different value. */
564 	first_inquiry_len = sdev->inquiry_len ? sdev->inquiry_len : 36;
565 	try_inquiry_len = first_inquiry_len;
566 	pass = 1;
567 
568  next_pass:
569 	SCSI_LOG_SCAN_BUS(3, sdev_printk(KERN_INFO, sdev,
570 				"scsi scan: INQUIRY pass %d length %d\n",
571 				pass, try_inquiry_len));
572 
573 	/* Each pass gets up to three chances to ignore Unit Attention */
574 	for (count = 0; count < 3; ++count) {
575 		memset(scsi_cmd, 0, 6);
576 		scsi_cmd[0] = INQUIRY;
577 		scsi_cmd[4] = (unsigned char) try_inquiry_len;
578 
579 		memset(inq_result, 0, try_inquiry_len);
580 
581 		result = scsi_execute_req(sdev,  scsi_cmd, DMA_FROM_DEVICE,
582 					  inq_result, try_inquiry_len, &sshdr,
583 					  HZ / 2 + HZ * scsi_inq_timeout, 3);
584 
585 		SCSI_LOG_SCAN_BUS(3, printk(KERN_INFO "scsi scan: INQUIRY %s "
586 				"with code 0x%x\n",
587 				result ? "failed" : "successful", result));
588 
589 		if (result) {
590 			/*
591 			 * not-ready to ready transition [asc/ascq=0x28/0x0]
592 			 * or power-on, reset [asc/ascq=0x29/0x0], continue.
593 			 * INQUIRY should not yield UNIT_ATTENTION
594 			 * but many buggy devices do so anyway.
595 			 */
596 			if ((driver_byte(result) & DRIVER_SENSE) &&
597 			    scsi_sense_valid(&sshdr)) {
598 				if ((sshdr.sense_key == UNIT_ATTENTION) &&
599 				    ((sshdr.asc == 0x28) ||
600 				     (sshdr.asc == 0x29)) &&
601 				    (sshdr.ascq == 0))
602 					continue;
603 			}
604 		}
605 		break;
606 	}
607 
608 	if (result == 0) {
609 		sanitize_inquiry_string(&inq_result[8], 8);
610 		sanitize_inquiry_string(&inq_result[16], 16);
611 		sanitize_inquiry_string(&inq_result[32], 4);
612 
613 		response_len = inq_result[4] + 5;
614 		if (response_len > 255)
615 			response_len = first_inquiry_len;	/* sanity */
616 
617 		/*
618 		 * Get any flags for this device.
619 		 *
620 		 * XXX add a bflags to scsi_device, and replace the
621 		 * corresponding bit fields in scsi_device, so bflags
622 		 * need not be passed as an argument.
623 		 */
624 		*bflags = scsi_get_device_flags(sdev, &inq_result[8],
625 				&inq_result[16]);
626 
627 		/* When the first pass succeeds we gain information about
628 		 * what larger transfer lengths might work. */
629 		if (pass == 1) {
630 			if (BLIST_INQUIRY_36 & *bflags)
631 				next_inquiry_len = 36;
632 			else if (BLIST_INQUIRY_58 & *bflags)
633 				next_inquiry_len = 58;
634 			else if (sdev->inquiry_len)
635 				next_inquiry_len = sdev->inquiry_len;
636 			else
637 				next_inquiry_len = response_len;
638 
639 			/* If more data is available perform the second pass */
640 			if (next_inquiry_len > try_inquiry_len) {
641 				try_inquiry_len = next_inquiry_len;
642 				pass = 2;
643 				goto next_pass;
644 			}
645 		}
646 
647 	} else if (pass == 2) {
648 		printk(KERN_INFO "scsi scan: %d byte inquiry failed.  "
649 				"Consider BLIST_INQUIRY_36 for this device\n",
650 				try_inquiry_len);
651 
652 		/* If this pass failed, the third pass goes back and transfers
653 		 * the same amount as we successfully got in the first pass. */
654 		try_inquiry_len = first_inquiry_len;
655 		pass = 3;
656 		goto next_pass;
657 	}
658 
659 	/* If the last transfer attempt got an error, assume the
660 	 * peripheral doesn't exist or is dead. */
661 	if (result)
662 		return -EIO;
663 
664 	/* Don't report any more data than the device says is valid */
665 	sdev->inquiry_len = min(try_inquiry_len, response_len);
666 
667 	/*
668 	 * XXX Abort if the response length is less than 36? If less than
669 	 * 32, the lookup of the device flags (above) could be invalid,
670 	 * and it would be possible to take an incorrect action - we do
671 	 * not want to hang because of a short INQUIRY. On the flip side,
672 	 * if the device is spun down or becoming ready (and so it gives a
673 	 * short INQUIRY), an abort here prevents any further use of the
674 	 * device, including spin up.
675 	 *
676 	 * On the whole, the best approach seems to be to assume the first
677 	 * 36 bytes are valid no matter what the device says.  That's
678 	 * better than copying < 36 bytes to the inquiry-result buffer
679 	 * and displaying garbage for the Vendor, Product, or Revision
680 	 * strings.
681 	 */
682 	if (sdev->inquiry_len < 36) {
683 		printk(KERN_INFO "scsi scan: INQUIRY result too short (%d),"
684 				" using 36\n", sdev->inquiry_len);
685 		sdev->inquiry_len = 36;
686 	}
687 
688 	/*
689 	 * Related to the above issue:
690 	 *
691 	 * XXX Devices (disk or all?) should be sent a TEST UNIT READY,
692 	 * and if not ready, sent a START_STOP to start (maybe spin up) and
693 	 * then send the INQUIRY again, since the INQUIRY can change after
694 	 * a device is initialized.
695 	 *
696 	 * Ideally, start a device if explicitly asked to do so.  This
697 	 * assumes that a device is spun up on power on, spun down on
698 	 * request, and then spun up on request.
699 	 */
700 
701 	/*
702 	 * The scanning code needs to know the scsi_level, even if no
703 	 * device is attached at LUN 0 (SCSI_SCAN_TARGET_PRESENT) so
704 	 * non-zero LUNs can be scanned.
705 	 */
706 	sdev->scsi_level = inq_result[2] & 0x07;
707 	if (sdev->scsi_level >= 2 ||
708 	    (sdev->scsi_level == 1 && (inq_result[3] & 0x0f) == 1))
709 		sdev->scsi_level++;
710 	sdev->sdev_target->scsi_level = sdev->scsi_level;
711 
712 	return 0;
713 }
714 
715 /**
716  * scsi_add_lun - allocate and fully initialze a scsi_device
717  * @sdev:	holds information to be stored in the new scsi_device
718  * @inq_result:	holds the result of a previous INQUIRY to the LUN
719  * @bflags:	black/white list flag
720  * @async:	1 if this device is being scanned asynchronously
721  *
722  * Description:
723  *     Initialize the scsi_device @sdev.  Optionally set fields based
724  *     on values in *@bflags.
725  *
726  * Return:
727  *     SCSI_SCAN_NO_RESPONSE: could not allocate or setup a scsi_device
728  *     SCSI_SCAN_LUN_PRESENT: a new scsi_device was allocated and initialized
729  **/
730 static int scsi_add_lun(struct scsi_device *sdev, unsigned char *inq_result,
731 		int *bflags, int async)
732 {
733 	/*
734 	 * XXX do not save the inquiry, since it can change underneath us,
735 	 * save just vendor/model/rev.
736 	 *
737 	 * Rather than save it and have an ioctl that retrieves the saved
738 	 * value, have an ioctl that executes the same INQUIRY code used
739 	 * in scsi_probe_lun, let user level programs doing INQUIRY
740 	 * scanning run at their own risk, or supply a user level program
741 	 * that can correctly scan.
742 	 */
743 
744 	/*
745 	 * Copy at least 36 bytes of INQUIRY data, so that we don't
746 	 * dereference unallocated memory when accessing the Vendor,
747 	 * Product, and Revision strings.  Badly behaved devices may set
748 	 * the INQUIRY Additional Length byte to a small value, indicating
749 	 * these strings are invalid, but often they contain plausible data
750 	 * nonetheless.  It doesn't matter if the device sent < 36 bytes
751 	 * total, since scsi_probe_lun() initializes inq_result with 0s.
752 	 */
753 	sdev->inquiry = kmemdup(inq_result,
754 				max_t(size_t, sdev->inquiry_len, 36),
755 				GFP_ATOMIC);
756 	if (sdev->inquiry == NULL)
757 		return SCSI_SCAN_NO_RESPONSE;
758 
759 	sdev->vendor = (char *) (sdev->inquiry + 8);
760 	sdev->model = (char *) (sdev->inquiry + 16);
761 	sdev->rev = (char *) (sdev->inquiry + 32);
762 
763 	if (*bflags & BLIST_ISROM) {
764 		sdev->type = TYPE_ROM;
765 		sdev->removable = 1;
766 	} else {
767 		sdev->type = (inq_result[0] & 0x1f);
768 		sdev->removable = (inq_result[1] & 0x80) >> 7;
769 	}
770 
771 	switch (sdev->type) {
772 	case TYPE_RBC:
773 	case TYPE_TAPE:
774 	case TYPE_DISK:
775 	case TYPE_PRINTER:
776 	case TYPE_MOD:
777 	case TYPE_PROCESSOR:
778 	case TYPE_SCANNER:
779 	case TYPE_MEDIUM_CHANGER:
780 	case TYPE_ENCLOSURE:
781 	case TYPE_COMM:
782 	case TYPE_RAID:
783 		sdev->writeable = 1;
784 		break;
785 	case TYPE_ROM:
786 	case TYPE_WORM:
787 		sdev->writeable = 0;
788 		break;
789 	default:
790 		printk(KERN_INFO "scsi: unknown device type %d\n", sdev->type);
791 	}
792 
793 	if (sdev->type == TYPE_RBC || sdev->type == TYPE_ROM) {
794 		/* RBC and MMC devices can return SCSI-3 compliance and yet
795 		 * still not support REPORT LUNS, so make them act as
796 		 * BLIST_NOREPORTLUN unless BLIST_REPORTLUN2 is
797 		 * specifically set */
798 		if ((*bflags & BLIST_REPORTLUN2) == 0)
799 			*bflags |= BLIST_NOREPORTLUN;
800 	}
801 
802 	/*
803 	 * For a peripheral qualifier (PQ) value of 1 (001b), the SCSI
804 	 * spec says: The device server is capable of supporting the
805 	 * specified peripheral device type on this logical unit. However,
806 	 * the physical device is not currently connected to this logical
807 	 * unit.
808 	 *
809 	 * The above is vague, as it implies that we could treat 001 and
810 	 * 011 the same. Stay compatible with previous code, and create a
811 	 * scsi_device for a PQ of 1
812 	 *
813 	 * Don't set the device offline here; rather let the upper
814 	 * level drivers eval the PQ to decide whether they should
815 	 * attach. So remove ((inq_result[0] >> 5) & 7) == 1 check.
816 	 */
817 
818 	sdev->inq_periph_qual = (inq_result[0] >> 5) & 7;
819 	sdev->lockable = sdev->removable;
820 	sdev->soft_reset = (inq_result[7] & 1) && ((inq_result[3] & 7) == 2);
821 
822 	if (sdev->scsi_level >= SCSI_3 ||
823 			(sdev->inquiry_len > 56 && inq_result[56] & 0x04))
824 		sdev->ppr = 1;
825 	if (inq_result[7] & 0x60)
826 		sdev->wdtr = 1;
827 	if (inq_result[7] & 0x10)
828 		sdev->sdtr = 1;
829 
830 	sdev_printk(KERN_NOTICE, sdev, "%s %.8s %.16s %.4s PQ: %d "
831 			"ANSI: %d%s\n", scsi_device_type(sdev->type),
832 			sdev->vendor, sdev->model, sdev->rev,
833 			sdev->inq_periph_qual, inq_result[2] & 0x07,
834 			(inq_result[3] & 0x0f) == 1 ? " CCS" : "");
835 
836 	if ((sdev->scsi_level >= SCSI_2) && (inq_result[7] & 2) &&
837 	    !(*bflags & BLIST_NOTQ))
838 		sdev->tagged_supported = 1;
839 
840 	/*
841 	 * Some devices (Texel CD ROM drives) have handshaking problems
842 	 * when used with the Seagate controllers. borken is initialized
843 	 * to 1, and then set it to 0 here.
844 	 */
845 	if ((*bflags & BLIST_BORKEN) == 0)
846 		sdev->borken = 0;
847 
848 	if (*bflags & BLIST_NO_ULD_ATTACH)
849 		sdev->no_uld_attach = 1;
850 
851 	/*
852 	 * Apparently some really broken devices (contrary to the SCSI
853 	 * standards) need to be selected without asserting ATN
854 	 */
855 	if (*bflags & BLIST_SELECT_NO_ATN)
856 		sdev->select_no_atn = 1;
857 
858 	/*
859 	 * Maximum 512 sector transfer length
860 	 * broken RA4x00 Compaq Disk Array
861 	 */
862 	if (*bflags & BLIST_MAX_512)
863 		blk_queue_max_sectors(sdev->request_queue, 512);
864 
865 	/*
866 	 * Some devices may not want to have a start command automatically
867 	 * issued when a device is added.
868 	 */
869 	if (*bflags & BLIST_NOSTARTONADD)
870 		sdev->no_start_on_add = 1;
871 
872 	if (*bflags & BLIST_SINGLELUN)
873 		scsi_target(sdev)->single_lun = 1;
874 
875 	sdev->use_10_for_rw = 1;
876 
877 	if (*bflags & BLIST_MS_SKIP_PAGE_08)
878 		sdev->skip_ms_page_8 = 1;
879 
880 	if (*bflags & BLIST_MS_SKIP_PAGE_3F)
881 		sdev->skip_ms_page_3f = 1;
882 
883 	if (*bflags & BLIST_USE_10_BYTE_MS)
884 		sdev->use_10_for_ms = 1;
885 
886 	/* set the device running here so that slave configure
887 	 * may do I/O */
888 	scsi_device_set_state(sdev, SDEV_RUNNING);
889 
890 	if (*bflags & BLIST_MS_192_BYTES_FOR_3F)
891 		sdev->use_192_bytes_for_3f = 1;
892 
893 	if (*bflags & BLIST_NOT_LOCKABLE)
894 		sdev->lockable = 0;
895 
896 	if (*bflags & BLIST_RETRY_HWERROR)
897 		sdev->retry_hwerror = 1;
898 
899 	transport_configure_device(&sdev->sdev_gendev);
900 
901 	if (sdev->host->hostt->slave_configure) {
902 		int ret = sdev->host->hostt->slave_configure(sdev);
903 		if (ret) {
904 			/*
905 			 * if LLDD reports slave not present, don't clutter
906 			 * console with alloc failure messages
907 			 */
908 			if (ret != -ENXIO) {
909 				sdev_printk(KERN_ERR, sdev,
910 					"failed to configure device\n");
911 			}
912 			return SCSI_SCAN_NO_RESPONSE;
913 		}
914 	}
915 
916 	/*
917 	 * Ok, the device is now all set up, we can
918 	 * register it and tell the rest of the kernel
919 	 * about it.
920 	 */
921 	if (!async && scsi_sysfs_add_sdev(sdev) != 0)
922 		return SCSI_SCAN_NO_RESPONSE;
923 
924 	return SCSI_SCAN_LUN_PRESENT;
925 }
926 
927 static inline void scsi_destroy_sdev(struct scsi_device *sdev)
928 {
929 	scsi_device_set_state(sdev, SDEV_DEL);
930 	if (sdev->host->hostt->slave_destroy)
931 		sdev->host->hostt->slave_destroy(sdev);
932 	transport_destroy_device(&sdev->sdev_gendev);
933 	put_device(&sdev->sdev_gendev);
934 }
935 
936 #ifdef CONFIG_SCSI_LOGGING
937 /**
938  * scsi_inq_str - print INQUIRY data from min to max index, strip trailing whitespace
939  * @buf:   Output buffer with at least end-first+1 bytes of space
940  * @inq:   Inquiry buffer (input)
941  * @first: Offset of string into inq
942  * @end:   Index after last character in inq
943  */
944 static unsigned char *scsi_inq_str(unsigned char *buf, unsigned char *inq,
945 				   unsigned first, unsigned end)
946 {
947 	unsigned term = 0, idx;
948 
949 	for (idx = 0; idx + first < end && idx + first < inq[4] + 5; idx++) {
950 		if (inq[idx+first] > ' ') {
951 			buf[idx] = inq[idx+first];
952 			term = idx+1;
953 		} else {
954 			buf[idx] = ' ';
955 		}
956 	}
957 	buf[term] = 0;
958 	return buf;
959 }
960 #endif
961 
962 /**
963  * scsi_probe_and_add_lun - probe a LUN, if a LUN is found add it
964  * @starget:	pointer to target device structure
965  * @lun:	LUN of target device
966  * @bflagsp:	store bflags here if not NULL
967  * @sdevp:	probe the LUN corresponding to this scsi_device
968  * @rescan:     if nonzero skip some code only needed on first scan
969  * @hostdata:	passed to scsi_alloc_sdev()
970  *
971  * Description:
972  *     Call scsi_probe_lun, if a LUN with an attached device is found,
973  *     allocate and set it up by calling scsi_add_lun.
974  *
975  * Return:
976  *     SCSI_SCAN_NO_RESPONSE: could not allocate or setup a scsi_device
977  *     SCSI_SCAN_TARGET_PRESENT: target responded, but no device is
978  *         attached at the LUN
979  *     SCSI_SCAN_LUN_PRESENT: a new scsi_device was allocated and initialized
980  **/
981 static int scsi_probe_and_add_lun(struct scsi_target *starget,
982 				  uint lun, int *bflagsp,
983 				  struct scsi_device **sdevp, int rescan,
984 				  void *hostdata)
985 {
986 	struct scsi_device *sdev;
987 	unsigned char *result;
988 	int bflags, res = SCSI_SCAN_NO_RESPONSE, result_len = 256;
989 	struct Scsi_Host *shost = dev_to_shost(starget->dev.parent);
990 
991 	/*
992 	 * The rescan flag is used as an optimization, the first scan of a
993 	 * host adapter calls into here with rescan == 0.
994 	 */
995 	sdev = scsi_device_lookup_by_target(starget, lun);
996 	if (sdev) {
997 		if (rescan || sdev->sdev_state != SDEV_CREATED) {
998 			SCSI_LOG_SCAN_BUS(3, printk(KERN_INFO
999 				"scsi scan: device exists on %s\n",
1000 				sdev->sdev_gendev.bus_id));
1001 			if (sdevp)
1002 				*sdevp = sdev;
1003 			else
1004 				scsi_device_put(sdev);
1005 
1006 			if (bflagsp)
1007 				*bflagsp = scsi_get_device_flags(sdev,
1008 								 sdev->vendor,
1009 								 sdev->model);
1010 			return SCSI_SCAN_LUN_PRESENT;
1011 		}
1012 		scsi_device_put(sdev);
1013 	} else
1014 		sdev = scsi_alloc_sdev(starget, lun, hostdata);
1015 	if (!sdev)
1016 		goto out;
1017 
1018 	result = kmalloc(result_len, GFP_ATOMIC |
1019 			((shost->unchecked_isa_dma) ? __GFP_DMA : 0));
1020 	if (!result)
1021 		goto out_free_sdev;
1022 
1023 	if (scsi_probe_lun(sdev, result, result_len, &bflags))
1024 		goto out_free_result;
1025 
1026 	if (bflagsp)
1027 		*bflagsp = bflags;
1028 	/*
1029 	 * result contains valid SCSI INQUIRY data.
1030 	 */
1031 	if (((result[0] >> 5) == 3) && !(bflags & BLIST_ATTACH_PQ3)) {
1032 		/*
1033 		 * For a Peripheral qualifier 3 (011b), the SCSI
1034 		 * spec says: The device server is not capable of
1035 		 * supporting a physical device on this logical
1036 		 * unit.
1037 		 *
1038 		 * For disks, this implies that there is no
1039 		 * logical disk configured at sdev->lun, but there
1040 		 * is a target id responding.
1041 		 */
1042 		SCSI_LOG_SCAN_BUS(2, sdev_printk(KERN_INFO, sdev, "scsi scan:"
1043 				   " peripheral qualifier of 3, device not"
1044 				   " added\n"))
1045 		if (lun == 0) {
1046 			SCSI_LOG_SCAN_BUS(1, {
1047 				unsigned char vend[9];
1048 				unsigned char mod[17];
1049 
1050 				sdev_printk(KERN_INFO, sdev,
1051 					"scsi scan: consider passing scsi_mod."
1052 					"dev_flags=%s:%s:0x240 or 0x1000240\n",
1053 					scsi_inq_str(vend, result, 8, 16),
1054 					scsi_inq_str(mod, result, 16, 32));
1055 			});
1056 
1057 		}
1058 
1059 		res = SCSI_SCAN_TARGET_PRESENT;
1060 		goto out_free_result;
1061 	}
1062 
1063 	/*
1064 	 * Some targets may set slight variations of PQ and PDT to signal
1065 	 * that no LUN is present, so don't add sdev in these cases.
1066 	 * Two specific examples are:
1067 	 * 1) NetApp targets: return PQ=1, PDT=0x1f
1068 	 * 2) USB UFI: returns PDT=0x1f, with the PQ bits being "reserved"
1069 	 *    in the UFI 1.0 spec (we cannot rely on reserved bits).
1070 	 *
1071 	 * References:
1072 	 * 1) SCSI SPC-3, pp. 145-146
1073 	 * PQ=1: "A peripheral device having the specified peripheral
1074 	 * device type is not connected to this logical unit. However, the
1075 	 * device server is capable of supporting the specified peripheral
1076 	 * device type on this logical unit."
1077 	 * PDT=0x1f: "Unknown or no device type"
1078 	 * 2) USB UFI 1.0, p. 20
1079 	 * PDT=00h Direct-access device (floppy)
1080 	 * PDT=1Fh none (no FDD connected to the requested logical unit)
1081 	 */
1082 	if (((result[0] >> 5) == 1 || starget->pdt_1f_for_no_lun) &&
1083 	     (result[0] & 0x1f) == 0x1f) {
1084 		SCSI_LOG_SCAN_BUS(3, printk(KERN_INFO
1085 					"scsi scan: peripheral device type"
1086 					" of 31, no device added\n"));
1087 		res = SCSI_SCAN_TARGET_PRESENT;
1088 		goto out_free_result;
1089 	}
1090 
1091 	res = scsi_add_lun(sdev, result, &bflags, shost->async_scan);
1092 	if (res == SCSI_SCAN_LUN_PRESENT) {
1093 		if (bflags & BLIST_KEY) {
1094 			sdev->lockable = 0;
1095 			scsi_unlock_floptical(sdev, result);
1096 		}
1097 	}
1098 
1099  out_free_result:
1100 	kfree(result);
1101  out_free_sdev:
1102 	if (res == SCSI_SCAN_LUN_PRESENT) {
1103 		if (sdevp) {
1104 			if (scsi_device_get(sdev) == 0) {
1105 				*sdevp = sdev;
1106 			} else {
1107 				__scsi_remove_device(sdev);
1108 				res = SCSI_SCAN_NO_RESPONSE;
1109 			}
1110 		}
1111 	} else
1112 		scsi_destroy_sdev(sdev);
1113  out:
1114 	return res;
1115 }
1116 
1117 /**
1118  * scsi_sequential_lun_scan - sequentially scan a SCSI target
1119  * @starget:	pointer to target structure to scan
1120  * @bflags:	black/white list flag for LUN 0
1121  * @scsi_level: Which version of the standard does this device adhere to
1122  * @rescan:     passed to scsi_probe_add_lun()
1123  *
1124  * Description:
1125  *     Generally, scan from LUN 1 (LUN 0 is assumed to already have been
1126  *     scanned) to some maximum lun until a LUN is found with no device
1127  *     attached. Use the bflags to figure out any oddities.
1128  *
1129  *     Modifies sdevscan->lun.
1130  **/
1131 static void scsi_sequential_lun_scan(struct scsi_target *starget,
1132 				     int bflags, int scsi_level, int rescan)
1133 {
1134 	unsigned int sparse_lun, lun, max_dev_lun;
1135 	struct Scsi_Host *shost = dev_to_shost(starget->dev.parent);
1136 
1137 	SCSI_LOG_SCAN_BUS(3, printk(KERN_INFO "scsi scan: Sequential scan of"
1138 				    "%s\n", starget->dev.bus_id));
1139 
1140 	max_dev_lun = min(max_scsi_luns, shost->max_lun);
1141 	/*
1142 	 * If this device is known to support sparse multiple units,
1143 	 * override the other settings, and scan all of them. Normally,
1144 	 * SCSI-3 devices should be scanned via the REPORT LUNS.
1145 	 */
1146 	if (bflags & BLIST_SPARSELUN) {
1147 		max_dev_lun = shost->max_lun;
1148 		sparse_lun = 1;
1149 	} else
1150 		sparse_lun = 0;
1151 
1152 	/*
1153 	 * If less than SCSI_1_CSS, and no special lun scaning, stop
1154 	 * scanning; this matches 2.4 behaviour, but could just be a bug
1155 	 * (to continue scanning a SCSI_1_CSS device).
1156 	 *
1157 	 * This test is broken.  We might not have any device on lun0 for
1158 	 * a sparselun device, and if that's the case then how would we
1159 	 * know the real scsi_level, eh?  It might make sense to just not
1160 	 * scan any SCSI_1 device for non-0 luns, but that check would best
1161 	 * go into scsi_alloc_sdev() and just have it return null when asked
1162 	 * to alloc an sdev for lun > 0 on an already found SCSI_1 device.
1163 	 *
1164 	if ((sdevscan->scsi_level < SCSI_1_CCS) &&
1165 	    ((bflags & (BLIST_FORCELUN | BLIST_SPARSELUN | BLIST_MAX5LUN))
1166 	     == 0))
1167 		return;
1168 	 */
1169 	/*
1170 	 * If this device is known to support multiple units, override
1171 	 * the other settings, and scan all of them.
1172 	 */
1173 	if (bflags & BLIST_FORCELUN)
1174 		max_dev_lun = shost->max_lun;
1175 	/*
1176 	 * REGAL CDC-4X: avoid hang after LUN 4
1177 	 */
1178 	if (bflags & BLIST_MAX5LUN)
1179 		max_dev_lun = min(5U, max_dev_lun);
1180 	/*
1181 	 * Do not scan SCSI-2 or lower device past LUN 7, unless
1182 	 * BLIST_LARGELUN.
1183 	 */
1184 	if (scsi_level < SCSI_3 && !(bflags & BLIST_LARGELUN))
1185 		max_dev_lun = min(8U, max_dev_lun);
1186 
1187 	/*
1188 	 * We have already scanned LUN 0, so start at LUN 1. Keep scanning
1189 	 * until we reach the max, or no LUN is found and we are not
1190 	 * sparse_lun.
1191 	 */
1192 	for (lun = 1; lun < max_dev_lun; ++lun)
1193 		if ((scsi_probe_and_add_lun(starget, lun, NULL, NULL, rescan,
1194 					    NULL) != SCSI_SCAN_LUN_PRESENT) &&
1195 		    !sparse_lun)
1196 			return;
1197 }
1198 
1199 /**
1200  * scsilun_to_int: convert a scsi_lun to an int
1201  * @scsilun:	struct scsi_lun to be converted.
1202  *
1203  * Description:
1204  *     Convert @scsilun from a struct scsi_lun to a four byte host byte-ordered
1205  *     integer, and return the result. The caller must check for
1206  *     truncation before using this function.
1207  *
1208  * Notes:
1209  *     The struct scsi_lun is assumed to be four levels, with each level
1210  *     effectively containing a SCSI byte-ordered (big endian) short; the
1211  *     addressing bits of each level are ignored (the highest two bits).
1212  *     For a description of the LUN format, post SCSI-3 see the SCSI
1213  *     Architecture Model, for SCSI-3 see the SCSI Controller Commands.
1214  *
1215  *     Given a struct scsi_lun of: 0a 04 0b 03 00 00 00 00, this function returns
1216  *     the integer: 0x0b030a04
1217  **/
1218 int scsilun_to_int(struct scsi_lun *scsilun)
1219 {
1220 	int i;
1221 	unsigned int lun;
1222 
1223 	lun = 0;
1224 	for (i = 0; i < sizeof(lun); i += 2)
1225 		lun = lun | (((scsilun->scsi_lun[i] << 8) |
1226 			      scsilun->scsi_lun[i + 1]) << (i * 8));
1227 	return lun;
1228 }
1229 EXPORT_SYMBOL(scsilun_to_int);
1230 
1231 /**
1232  * int_to_scsilun: reverts an int into a scsi_lun
1233  * @lun:        integer to be reverted
1234  * @scsilun:	struct scsi_lun to be set.
1235  *
1236  * Description:
1237  *     Reverts the functionality of the scsilun_to_int, which packed
1238  *     an 8-byte lun value into an int. This routine unpacks the int
1239  *     back into the lun value.
1240  *     Note: the scsilun_to_int() routine does not truly handle all
1241  *     8bytes of the lun value. This functions restores only as much
1242  *     as was set by the routine.
1243  *
1244  * Notes:
1245  *     Given an integer : 0x0b030a04,  this function returns a
1246  *     scsi_lun of : struct scsi_lun of: 0a 04 0b 03 00 00 00 00
1247  *
1248  **/
1249 void int_to_scsilun(unsigned int lun, struct scsi_lun *scsilun)
1250 {
1251 	int i;
1252 
1253 	memset(scsilun->scsi_lun, 0, sizeof(scsilun->scsi_lun));
1254 
1255 	for (i = 0; i < sizeof(lun); i += 2) {
1256 		scsilun->scsi_lun[i] = (lun >> 8) & 0xFF;
1257 		scsilun->scsi_lun[i+1] = lun & 0xFF;
1258 		lun = lun >> 16;
1259 	}
1260 }
1261 EXPORT_SYMBOL(int_to_scsilun);
1262 
1263 /**
1264  * scsi_report_lun_scan - Scan using SCSI REPORT LUN results
1265  * @starget: which target
1266  * @bflags: Zero or a mix of BLIST_NOLUN, BLIST_REPORTLUN2, or BLIST_NOREPORTLUN
1267  * @rescan: nonzero if we can skip code only needed on first scan
1268  *
1269  * Description:
1270  *   Fast scanning for modern (SCSI-3) devices by sending a REPORT LUN command.
1271  *   Scan the resulting list of LUNs by calling scsi_probe_and_add_lun.
1272  *
1273  *   If BLINK_REPORTLUN2 is set, scan a target that supports more than 8
1274  *   LUNs even if it's older than SCSI-3.
1275  *   If BLIST_NOREPORTLUN is set, return 1 always.
1276  *   If BLIST_NOLUN is set, return 0 always.
1277  *
1278  * Return:
1279  *     0: scan completed (or no memory, so further scanning is futile)
1280  *     1: could not scan with REPORT LUN
1281  **/
1282 static int scsi_report_lun_scan(struct scsi_target *starget, int bflags,
1283 				int rescan)
1284 {
1285 	char devname[64];
1286 	unsigned char scsi_cmd[MAX_COMMAND_SIZE];
1287 	unsigned int length;
1288 	unsigned int lun;
1289 	unsigned int num_luns;
1290 	unsigned int retries;
1291 	int result;
1292 	struct scsi_lun *lunp, *lun_data;
1293 	u8 *data;
1294 	struct scsi_sense_hdr sshdr;
1295 	struct scsi_device *sdev;
1296 	struct Scsi_Host *shost = dev_to_shost(&starget->dev);
1297 	int ret = 0;
1298 
1299 	/*
1300 	 * Only support SCSI-3 and up devices if BLIST_NOREPORTLUN is not set.
1301 	 * Also allow SCSI-2 if BLIST_REPORTLUN2 is set and host adapter does
1302 	 * support more than 8 LUNs.
1303 	 */
1304 	if (bflags & BLIST_NOREPORTLUN)
1305 		return 1;
1306 	if (starget->scsi_level < SCSI_2 &&
1307 	    starget->scsi_level != SCSI_UNKNOWN)
1308 		return 1;
1309 	if (starget->scsi_level < SCSI_3 &&
1310 	    (!(bflags & BLIST_REPORTLUN2) || shost->max_lun <= 8))
1311 		return 1;
1312 	if (bflags & BLIST_NOLUN)
1313 		return 0;
1314 
1315 	if (!(sdev = scsi_device_lookup_by_target(starget, 0))) {
1316 		sdev = scsi_alloc_sdev(starget, 0, NULL);
1317 		if (!sdev)
1318 			return 0;
1319 		if (scsi_device_get(sdev))
1320 			return 0;
1321 	}
1322 
1323 	sprintf(devname, "host %d channel %d id %d",
1324 		shost->host_no, sdev->channel, sdev->id);
1325 
1326 	/*
1327 	 * Allocate enough to hold the header (the same size as one scsi_lun)
1328 	 * plus the max number of luns we are requesting.
1329 	 *
1330 	 * Reallocating and trying again (with the exact amount we need)
1331 	 * would be nice, but then we need to somehow limit the size
1332 	 * allocated based on the available memory and the limits of
1333 	 * kmalloc - we don't want a kmalloc() failure of a huge value to
1334 	 * prevent us from finding any LUNs on this target.
1335 	 */
1336 	length = (max_scsi_report_luns + 1) * sizeof(struct scsi_lun);
1337 	lun_data = kmalloc(length, GFP_ATOMIC |
1338 			   (sdev->host->unchecked_isa_dma ? __GFP_DMA : 0));
1339 	if (!lun_data) {
1340 		printk(ALLOC_FAILURE_MSG, __FUNCTION__);
1341 		goto out;
1342 	}
1343 
1344 	scsi_cmd[0] = REPORT_LUNS;
1345 
1346 	/*
1347 	 * bytes 1 - 5: reserved, set to zero.
1348 	 */
1349 	memset(&scsi_cmd[1], 0, 5);
1350 
1351 	/*
1352 	 * bytes 6 - 9: length of the command.
1353 	 */
1354 	scsi_cmd[6] = (unsigned char) (length >> 24) & 0xff;
1355 	scsi_cmd[7] = (unsigned char) (length >> 16) & 0xff;
1356 	scsi_cmd[8] = (unsigned char) (length >> 8) & 0xff;
1357 	scsi_cmd[9] = (unsigned char) length & 0xff;
1358 
1359 	scsi_cmd[10] = 0;	/* reserved */
1360 	scsi_cmd[11] = 0;	/* control */
1361 
1362 	/*
1363 	 * We can get a UNIT ATTENTION, for example a power on/reset, so
1364 	 * retry a few times (like sd.c does for TEST UNIT READY).
1365 	 * Experience shows some combinations of adapter/devices get at
1366 	 * least two power on/resets.
1367 	 *
1368 	 * Illegal requests (for devices that do not support REPORT LUNS)
1369 	 * should come through as a check condition, and will not generate
1370 	 * a retry.
1371 	 */
1372 	for (retries = 0; retries < 3; retries++) {
1373 		SCSI_LOG_SCAN_BUS(3, printk (KERN_INFO "scsi scan: Sending"
1374 				" REPORT LUNS to %s (try %d)\n", devname,
1375 				retries));
1376 
1377 		result = scsi_execute_req(sdev, scsi_cmd, DMA_FROM_DEVICE,
1378 					  lun_data, length, &sshdr,
1379 					  SCSI_TIMEOUT + 4 * HZ, 3);
1380 
1381 		SCSI_LOG_SCAN_BUS(3, printk (KERN_INFO "scsi scan: REPORT LUNS"
1382 				" %s (try %d) result 0x%x\n", result
1383 				?  "failed" : "successful", retries, result));
1384 		if (result == 0)
1385 			break;
1386 		else if (scsi_sense_valid(&sshdr)) {
1387 			if (sshdr.sense_key != UNIT_ATTENTION)
1388 				break;
1389 		}
1390 	}
1391 
1392 	if (result) {
1393 		/*
1394 		 * The device probably does not support a REPORT LUN command
1395 		 */
1396 		ret = 1;
1397 		goto out_err;
1398 	}
1399 
1400 	/*
1401 	 * Get the length from the first four bytes of lun_data.
1402 	 */
1403 	data = (u8 *) lun_data->scsi_lun;
1404 	length = ((data[0] << 24) | (data[1] << 16) |
1405 		  (data[2] << 8) | (data[3] << 0));
1406 
1407 	num_luns = (length / sizeof(struct scsi_lun));
1408 	if (num_luns > max_scsi_report_luns) {
1409 		printk(KERN_WARNING "scsi: On %s only %d (max_scsi_report_luns)"
1410 		       " of %d luns reported, try increasing"
1411 		       " max_scsi_report_luns.\n", devname,
1412 		       max_scsi_report_luns, num_luns);
1413 		num_luns = max_scsi_report_luns;
1414 	}
1415 
1416 	SCSI_LOG_SCAN_BUS(3, sdev_printk (KERN_INFO, sdev,
1417 		"scsi scan: REPORT LUN scan\n"));
1418 
1419 	/*
1420 	 * Scan the luns in lun_data. The entry at offset 0 is really
1421 	 * the header, so start at 1 and go up to and including num_luns.
1422 	 */
1423 	for (lunp = &lun_data[1]; lunp <= &lun_data[num_luns]; lunp++) {
1424 		lun = scsilun_to_int(lunp);
1425 
1426 		/*
1427 		 * Check if the unused part of lunp is non-zero, and so
1428 		 * does not fit in lun.
1429 		 */
1430 		if (memcmp(&lunp->scsi_lun[sizeof(lun)], "\0\0\0\0", 4)) {
1431 			int i;
1432 
1433 			/*
1434 			 * Output an error displaying the LUN in byte order,
1435 			 * this differs from what linux would print for the
1436 			 * integer LUN value.
1437 			 */
1438 			printk(KERN_WARNING "scsi: %s lun 0x", devname);
1439 			data = (char *)lunp->scsi_lun;
1440 			for (i = 0; i < sizeof(struct scsi_lun); i++)
1441 				printk("%02x", data[i]);
1442 			printk(" has a LUN larger than currently supported.\n");
1443 		} else if (lun > sdev->host->max_lun) {
1444 			printk(KERN_WARNING "scsi: %s lun%d has a LUN larger"
1445 			       " than allowed by the host adapter\n",
1446 			       devname, lun);
1447 		} else {
1448 			int res;
1449 
1450 			res = scsi_probe_and_add_lun(starget,
1451 				lun, NULL, NULL, rescan, NULL);
1452 			if (res == SCSI_SCAN_NO_RESPONSE) {
1453 				/*
1454 				 * Got some results, but now none, abort.
1455 				 */
1456 				sdev_printk(KERN_ERR, sdev,
1457 					"Unexpected response"
1458 				        " from lun %d while scanning, scan"
1459 				        " aborted\n", lun);
1460 				break;
1461 			}
1462 		}
1463 	}
1464 
1465  out_err:
1466 	kfree(lun_data);
1467  out:
1468 	scsi_device_put(sdev);
1469 	if (sdev->sdev_state == SDEV_CREATED)
1470 		/*
1471 		 * the sdev we used didn't appear in the report luns scan
1472 		 */
1473 		scsi_destroy_sdev(sdev);
1474 	return ret;
1475 }
1476 
1477 struct scsi_device *__scsi_add_device(struct Scsi_Host *shost, uint channel,
1478 				      uint id, uint lun, void *hostdata)
1479 {
1480 	struct scsi_device *sdev = ERR_PTR(-ENODEV);
1481 	struct device *parent = &shost->shost_gendev;
1482 	struct scsi_target *starget;
1483 
1484 	if (strncmp(scsi_scan_type, "none", 4) == 0)
1485 		return ERR_PTR(-ENODEV);
1486 
1487 	starget = scsi_alloc_target(parent, channel, id);
1488 	if (!starget)
1489 		return ERR_PTR(-ENOMEM);
1490 
1491 	mutex_lock(&shost->scan_mutex);
1492 	if (!shost->async_scan)
1493 		scsi_complete_async_scans();
1494 
1495 	if (scsi_host_scan_allowed(shost))
1496 		scsi_probe_and_add_lun(starget, lun, NULL, &sdev, 1, hostdata);
1497 	mutex_unlock(&shost->scan_mutex);
1498 	scsi_target_reap(starget);
1499 	put_device(&starget->dev);
1500 
1501 	return sdev;
1502 }
1503 EXPORT_SYMBOL(__scsi_add_device);
1504 
1505 int scsi_add_device(struct Scsi_Host *host, uint channel,
1506 		    uint target, uint lun)
1507 {
1508 	struct scsi_device *sdev =
1509 		__scsi_add_device(host, channel, target, lun, NULL);
1510 	if (IS_ERR(sdev))
1511 		return PTR_ERR(sdev);
1512 
1513 	scsi_device_put(sdev);
1514 	return 0;
1515 }
1516 EXPORT_SYMBOL(scsi_add_device);
1517 
1518 void scsi_rescan_device(struct device *dev)
1519 {
1520 	struct scsi_driver *drv;
1521 
1522 	if (!dev->driver)
1523 		return;
1524 
1525 	drv = to_scsi_driver(dev->driver);
1526 	if (try_module_get(drv->owner)) {
1527 		if (drv->rescan)
1528 			drv->rescan(dev);
1529 		module_put(drv->owner);
1530 	}
1531 }
1532 EXPORT_SYMBOL(scsi_rescan_device);
1533 
1534 static void __scsi_scan_target(struct device *parent, unsigned int channel,
1535 		unsigned int id, unsigned int lun, int rescan)
1536 {
1537 	struct Scsi_Host *shost = dev_to_shost(parent);
1538 	int bflags = 0;
1539 	int res;
1540 	struct scsi_target *starget;
1541 
1542 	if (shost->this_id == id)
1543 		/*
1544 		 * Don't scan the host adapter
1545 		 */
1546 		return;
1547 
1548 	starget = scsi_alloc_target(parent, channel, id);
1549 	if (!starget)
1550 		return;
1551 
1552 	if (lun != SCAN_WILD_CARD) {
1553 		/*
1554 		 * Scan for a specific host/chan/id/lun.
1555 		 */
1556 		scsi_probe_and_add_lun(starget, lun, NULL, NULL, rescan, NULL);
1557 		goto out_reap;
1558 	}
1559 
1560 	/*
1561 	 * Scan LUN 0, if there is some response, scan further. Ideally, we
1562 	 * would not configure LUN 0 until all LUNs are scanned.
1563 	 */
1564 	res = scsi_probe_and_add_lun(starget, 0, &bflags, NULL, rescan, NULL);
1565 	if (res == SCSI_SCAN_LUN_PRESENT || res == SCSI_SCAN_TARGET_PRESENT) {
1566 		if (scsi_report_lun_scan(starget, bflags, rescan) != 0)
1567 			/*
1568 			 * The REPORT LUN did not scan the target,
1569 			 * do a sequential scan.
1570 			 */
1571 			scsi_sequential_lun_scan(starget, bflags,
1572 						 starget->scsi_level, rescan);
1573 	}
1574 
1575  out_reap:
1576 	/* now determine if the target has any children at all
1577 	 * and if not, nuke it */
1578 	scsi_target_reap(starget);
1579 
1580 	put_device(&starget->dev);
1581 }
1582 
1583 /**
1584  * scsi_scan_target - scan a target id, possibly including all LUNs on the target.
1585  * @parent:	host to scan
1586  * @channel:	channel to scan
1587  * @id:		target id to scan
1588  * @lun:	Specific LUN to scan or SCAN_WILD_CARD
1589  * @rescan:	passed to LUN scanning routines
1590  *
1591  * Description:
1592  *     Scan the target id on @parent, @channel, and @id. Scan at least LUN 0,
1593  *     and possibly all LUNs on the target id.
1594  *
1595  *     First try a REPORT LUN scan, if that does not scan the target, do a
1596  *     sequential scan of LUNs on the target id.
1597  **/
1598 void scsi_scan_target(struct device *parent, unsigned int channel,
1599 		      unsigned int id, unsigned int lun, int rescan)
1600 {
1601 	struct Scsi_Host *shost = dev_to_shost(parent);
1602 
1603 	if (strncmp(scsi_scan_type, "none", 4) == 0)
1604 		return;
1605 
1606 	mutex_lock(&shost->scan_mutex);
1607 	if (!shost->async_scan)
1608 		scsi_complete_async_scans();
1609 
1610 	if (scsi_host_scan_allowed(shost))
1611 		__scsi_scan_target(parent, channel, id, lun, rescan);
1612 	mutex_unlock(&shost->scan_mutex);
1613 }
1614 EXPORT_SYMBOL(scsi_scan_target);
1615 
1616 static void scsi_scan_channel(struct Scsi_Host *shost, unsigned int channel,
1617 			      unsigned int id, unsigned int lun, int rescan)
1618 {
1619 	uint order_id;
1620 
1621 	if (id == SCAN_WILD_CARD)
1622 		for (id = 0; id < shost->max_id; ++id) {
1623 			/*
1624 			 * XXX adapter drivers when possible (FCP, iSCSI)
1625 			 * could modify max_id to match the current max,
1626 			 * not the absolute max.
1627 			 *
1628 			 * XXX add a shost id iterator, so for example,
1629 			 * the FC ID can be the same as a target id
1630 			 * without a huge overhead of sparse id's.
1631 			 */
1632 			if (shost->reverse_ordering)
1633 				/*
1634 				 * Scan from high to low id.
1635 				 */
1636 				order_id = shost->max_id - id - 1;
1637 			else
1638 				order_id = id;
1639 			__scsi_scan_target(&shost->shost_gendev, channel,
1640 					order_id, lun, rescan);
1641 		}
1642 	else
1643 		__scsi_scan_target(&shost->shost_gendev, channel,
1644 				id, lun, rescan);
1645 }
1646 
1647 int scsi_scan_host_selected(struct Scsi_Host *shost, unsigned int channel,
1648 			    unsigned int id, unsigned int lun, int rescan)
1649 {
1650 	SCSI_LOG_SCAN_BUS(3, shost_printk (KERN_INFO, shost,
1651 		"%s: <%u:%u:%u>\n",
1652 		__FUNCTION__, channel, id, lun));
1653 
1654 	if (((channel != SCAN_WILD_CARD) && (channel > shost->max_channel)) ||
1655 	    ((id != SCAN_WILD_CARD) && (id >= shost->max_id)) ||
1656 	    ((lun != SCAN_WILD_CARD) && (lun > shost->max_lun)))
1657 		return -EINVAL;
1658 
1659 	mutex_lock(&shost->scan_mutex);
1660 	if (!shost->async_scan)
1661 		scsi_complete_async_scans();
1662 
1663 	if (scsi_host_scan_allowed(shost)) {
1664 		if (channel == SCAN_WILD_CARD)
1665 			for (channel = 0; channel <= shost->max_channel;
1666 			     channel++)
1667 				scsi_scan_channel(shost, channel, id, lun,
1668 						  rescan);
1669 		else
1670 			scsi_scan_channel(shost, channel, id, lun, rescan);
1671 	}
1672 	mutex_unlock(&shost->scan_mutex);
1673 
1674 	return 0;
1675 }
1676 
1677 static void scsi_sysfs_add_devices(struct Scsi_Host *shost)
1678 {
1679 	struct scsi_device *sdev;
1680 	shost_for_each_device(sdev, shost) {
1681 		if (!scsi_host_scan_allowed(shost) ||
1682 		    scsi_sysfs_add_sdev(sdev) != 0)
1683 			scsi_destroy_sdev(sdev);
1684 	}
1685 }
1686 
1687 /**
1688  * scsi_prep_async_scan - prepare for an async scan
1689  * @shost: the host which will be scanned
1690  * Returns: a cookie to be passed to scsi_finish_async_scan()
1691  *
1692  * Tells the midlayer this host is going to do an asynchronous scan.
1693  * It reserves the host's position in the scanning list and ensures
1694  * that other asynchronous scans started after this one won't affect the
1695  * ordering of the discovered devices.
1696  */
1697 static struct async_scan_data *scsi_prep_async_scan(struct Scsi_Host *shost)
1698 {
1699 	struct async_scan_data *data;
1700 	unsigned long flags;
1701 
1702 	if (strncmp(scsi_scan_type, "sync", 4) == 0)
1703 		return NULL;
1704 
1705 	if (shost->async_scan) {
1706 		printk("%s called twice for host %d", __FUNCTION__,
1707 				shost->host_no);
1708 		dump_stack();
1709 		return NULL;
1710 	}
1711 
1712 	data = kmalloc(sizeof(*data), GFP_KERNEL);
1713 	if (!data)
1714 		goto err;
1715 	data->shost = scsi_host_get(shost);
1716 	if (!data->shost)
1717 		goto err;
1718 	init_completion(&data->prev_finished);
1719 
1720 	mutex_lock(&shost->scan_mutex);
1721 	spin_lock_irqsave(shost->host_lock, flags);
1722 	shost->async_scan = 1;
1723 	spin_unlock_irqrestore(shost->host_lock, flags);
1724 	mutex_unlock(&shost->scan_mutex);
1725 
1726 	spin_lock(&async_scan_lock);
1727 	if (list_empty(&scanning_hosts))
1728 		complete(&data->prev_finished);
1729 	list_add_tail(&data->list, &scanning_hosts);
1730 	spin_unlock(&async_scan_lock);
1731 
1732 	return data;
1733 
1734  err:
1735 	kfree(data);
1736 	return NULL;
1737 }
1738 
1739 /**
1740  * scsi_finish_async_scan - asynchronous scan has finished
1741  * @data: cookie returned from earlier call to scsi_prep_async_scan()
1742  *
1743  * All the devices currently attached to this host have been found.
1744  * This function announces all the devices it has found to the rest
1745  * of the system.
1746  */
1747 static void scsi_finish_async_scan(struct async_scan_data *data)
1748 {
1749 	struct Scsi_Host *shost;
1750 	unsigned long flags;
1751 
1752 	if (!data)
1753 		return;
1754 
1755 	shost = data->shost;
1756 
1757 	mutex_lock(&shost->scan_mutex);
1758 
1759 	if (!shost->async_scan) {
1760 		printk("%s called twice for host %d", __FUNCTION__,
1761 				shost->host_no);
1762 		dump_stack();
1763 		return;
1764 	}
1765 
1766 	wait_for_completion(&data->prev_finished);
1767 
1768 	scsi_sysfs_add_devices(shost);
1769 
1770 	spin_lock_irqsave(shost->host_lock, flags);
1771 	shost->async_scan = 0;
1772 	spin_unlock_irqrestore(shost->host_lock, flags);
1773 
1774 	mutex_unlock(&shost->scan_mutex);
1775 
1776 	spin_lock(&async_scan_lock);
1777 	list_del(&data->list);
1778 	if (!list_empty(&scanning_hosts)) {
1779 		struct async_scan_data *next = list_entry(scanning_hosts.next,
1780 				struct async_scan_data, list);
1781 		complete(&next->prev_finished);
1782 	}
1783 	spin_unlock(&async_scan_lock);
1784 
1785 	scsi_host_put(shost);
1786 	kfree(data);
1787 }
1788 
1789 static void do_scsi_scan_host(struct Scsi_Host *shost)
1790 {
1791 	if (shost->hostt->scan_finished) {
1792 		unsigned long start = jiffies;
1793 		if (shost->hostt->scan_start)
1794 			shost->hostt->scan_start(shost);
1795 
1796 		while (!shost->hostt->scan_finished(shost, jiffies - start))
1797 			msleep(10);
1798 	} else {
1799 		scsi_scan_host_selected(shost, SCAN_WILD_CARD, SCAN_WILD_CARD,
1800 				SCAN_WILD_CARD, 0);
1801 	}
1802 }
1803 
1804 static int do_scan_async(void *_data)
1805 {
1806 	struct async_scan_data *data = _data;
1807 	do_scsi_scan_host(data->shost);
1808 	scsi_finish_async_scan(data);
1809 	return 0;
1810 }
1811 
1812 /**
1813  * scsi_scan_host - scan the given adapter
1814  * @shost:	adapter to scan
1815  **/
1816 void scsi_scan_host(struct Scsi_Host *shost)
1817 {
1818 	struct task_struct *p;
1819 	struct async_scan_data *data;
1820 
1821 	if (strncmp(scsi_scan_type, "none", 4) == 0)
1822 		return;
1823 
1824 	data = scsi_prep_async_scan(shost);
1825 	if (!data) {
1826 		do_scsi_scan_host(shost);
1827 		return;
1828 	}
1829 
1830 	p = kthread_run(do_scan_async, data, "scsi_scan_%d", shost->host_no);
1831 	if (IS_ERR(p))
1832 		do_scan_async(data);
1833 }
1834 EXPORT_SYMBOL(scsi_scan_host);
1835 
1836 void scsi_forget_host(struct Scsi_Host *shost)
1837 {
1838 	struct scsi_device *sdev;
1839 	unsigned long flags;
1840 
1841  restart:
1842 	spin_lock_irqsave(shost->host_lock, flags);
1843 	list_for_each_entry(sdev, &shost->__devices, siblings) {
1844 		if (sdev->sdev_state == SDEV_DEL)
1845 			continue;
1846 		spin_unlock_irqrestore(shost->host_lock, flags);
1847 		__scsi_remove_device(sdev);
1848 		goto restart;
1849 	}
1850 	spin_unlock_irqrestore(shost->host_lock, flags);
1851 }
1852 
1853 /*
1854  * Function:    scsi_get_host_dev()
1855  *
1856  * Purpose:     Create a scsi_device that points to the host adapter itself.
1857  *
1858  * Arguments:   SHpnt   - Host that needs a scsi_device
1859  *
1860  * Lock status: None assumed.
1861  *
1862  * Returns:     The scsi_device or NULL
1863  *
1864  * Notes:
1865  *	Attach a single scsi_device to the Scsi_Host - this should
1866  *	be made to look like a "pseudo-device" that points to the
1867  *	HA itself.
1868  *
1869  *	Note - this device is not accessible from any high-level
1870  *	drivers (including generics), which is probably not
1871  *	optimal.  We can add hooks later to attach
1872  */
1873 struct scsi_device *scsi_get_host_dev(struct Scsi_Host *shost)
1874 {
1875 	struct scsi_device *sdev = NULL;
1876 	struct scsi_target *starget;
1877 
1878 	mutex_lock(&shost->scan_mutex);
1879 	if (!scsi_host_scan_allowed(shost))
1880 		goto out;
1881 	starget = scsi_alloc_target(&shost->shost_gendev, 0, shost->this_id);
1882 	if (!starget)
1883 		goto out;
1884 
1885 	sdev = scsi_alloc_sdev(starget, 0, NULL);
1886 	if (sdev) {
1887 		sdev->sdev_gendev.parent = get_device(&starget->dev);
1888 		sdev->borken = 0;
1889 	} else
1890 		scsi_target_reap(starget);
1891 	put_device(&starget->dev);
1892  out:
1893 	mutex_unlock(&shost->scan_mutex);
1894 	return sdev;
1895 }
1896 EXPORT_SYMBOL(scsi_get_host_dev);
1897 
1898 /*
1899  * Function:    scsi_free_host_dev()
1900  *
1901  * Purpose:     Free a scsi_device that points to the host adapter itself.
1902  *
1903  * Arguments:   SHpnt   - Host that needs a scsi_device
1904  *
1905  * Lock status: None assumed.
1906  *
1907  * Returns:     Nothing
1908  *
1909  * Notes:
1910  */
1911 void scsi_free_host_dev(struct scsi_device *sdev)
1912 {
1913 	BUG_ON(sdev->id != sdev->host->this_id);
1914 
1915 	scsi_destroy_sdev(sdev);
1916 }
1917 EXPORT_SYMBOL(scsi_free_host_dev);
1918 
1919