xref: /linux/drivers/scsi/scsi_scan.c (revision 863a930a40eb7f2d18534c2c166b22582f5c6cfd)
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/config.h>
29 #include <linux/module.h>
30 #include <linux/moduleparam.h>
31 #include <linux/init.h>
32 #include <linux/blkdev.h>
33 #include <asm/semaphore.h>
34 
35 #include <scsi/scsi.h>
36 #include <scsi/scsi_device.h>
37 #include <scsi/scsi_driver.h>
38 #include <scsi/scsi_devinfo.h>
39 #include <scsi/scsi_host.h>
40 #include <scsi/scsi_request.h>
41 #include <scsi/scsi_transport.h>
42 #include <scsi/scsi_eh.h>
43 
44 #include "scsi_priv.h"
45 #include "scsi_logging.h"
46 
47 #define ALLOC_FAILURE_MSG	KERN_ERR "%s: Allocation failure during" \
48 	" SCSI scanning, some SCSI devices might not be configured\n"
49 
50 /*
51  * Default timeout
52  */
53 #define SCSI_TIMEOUT (2*HZ)
54 
55 /*
56  * Prefix values for the SCSI id's (stored in driverfs name field)
57  */
58 #define SCSI_UID_SER_NUM 'S'
59 #define SCSI_UID_UNKNOWN 'Z'
60 
61 /*
62  * Return values of some of the scanning functions.
63  *
64  * SCSI_SCAN_NO_RESPONSE: no valid response received from the target, this
65  * includes allocation or general failures preventing IO from being sent.
66  *
67  * SCSI_SCAN_TARGET_PRESENT: target responded, but no device is available
68  * on the given LUN.
69  *
70  * SCSI_SCAN_LUN_PRESENT: target responded, and a device is available on a
71  * given LUN.
72  */
73 #define SCSI_SCAN_NO_RESPONSE		0
74 #define SCSI_SCAN_TARGET_PRESENT	1
75 #define SCSI_SCAN_LUN_PRESENT		2
76 
77 static char *scsi_null_device_strs = "nullnullnullnull";
78 
79 #define MAX_SCSI_LUNS	512
80 
81 #ifdef CONFIG_SCSI_MULTI_LUN
82 static unsigned int max_scsi_luns = MAX_SCSI_LUNS;
83 #else
84 static unsigned int max_scsi_luns = 1;
85 #endif
86 
87 module_param_named(max_luns, max_scsi_luns, int, S_IRUGO|S_IWUSR);
88 MODULE_PARM_DESC(max_luns,
89 		 "last scsi LUN (should be between 1 and 2^32-1)");
90 
91 /*
92  * max_scsi_report_luns: the maximum number of LUNS that will be
93  * returned from the REPORT LUNS command. 8 times this value must
94  * be allocated. In theory this could be up to an 8 byte value, but
95  * in practice, the maximum number of LUNs suppored by any device
96  * is about 16k.
97  */
98 static unsigned int max_scsi_report_luns = 511;
99 
100 module_param_named(max_report_luns, max_scsi_report_luns, int, S_IRUGO|S_IWUSR);
101 MODULE_PARM_DESC(max_report_luns,
102 		 "REPORT LUNS maximum number of LUNS received (should be"
103 		 " between 1 and 16384)");
104 
105 static unsigned int scsi_inq_timeout = SCSI_TIMEOUT/HZ+3;
106 
107 module_param_named(inq_timeout, scsi_inq_timeout, int, S_IRUGO|S_IWUSR);
108 MODULE_PARM_DESC(inq_timeout,
109 		 "Timeout (in seconds) waiting for devices to answer INQUIRY."
110 		 " Default is 5. Some non-compliant devices need more.");
111 
112 /**
113  * scsi_unlock_floptical - unlock device via a special MODE SENSE command
114  * @sdev:	scsi device to send command to
115  * @result:	area to store the result of the MODE SENSE
116  *
117  * Description:
118  *     Send a vendor specific MODE SENSE (not a MODE SELECT) command.
119  *     Called for BLIST_KEY devices.
120  **/
121 static void scsi_unlock_floptical(struct scsi_device *sdev,
122 				  unsigned char *result)
123 {
124 	unsigned char scsi_cmd[MAX_COMMAND_SIZE];
125 
126 	printk(KERN_NOTICE "scsi: unlocking floptical drive\n");
127 	scsi_cmd[0] = MODE_SENSE;
128 	scsi_cmd[1] = 0;
129 	scsi_cmd[2] = 0x2e;
130 	scsi_cmd[3] = 0;
131 	scsi_cmd[4] = 0x2a;     /* size */
132 	scsi_cmd[5] = 0;
133 	scsi_execute_req(sdev, scsi_cmd, DMA_FROM_DEVICE, result, 0x2a, NULL,
134 			 SCSI_TIMEOUT, 3);
135 }
136 
137 /**
138  * print_inquiry - printk the inquiry information
139  * @inq_result:	printk this SCSI INQUIRY
140  *
141  * Description:
142  *     printk the vendor, model, and other information found in the
143  *     INQUIRY data in @inq_result.
144  *
145  * Notes:
146  *     Remove this, and replace with a hotplug event that logs any
147  *     relevant information.
148  **/
149 static void print_inquiry(unsigned char *inq_result)
150 {
151 	int i;
152 
153 	printk(KERN_NOTICE "  Vendor: ");
154 	for (i = 8; i < 16; i++)
155 		if (inq_result[i] >= 0x20 && i < inq_result[4] + 5)
156 			printk("%c", inq_result[i]);
157 		else
158 			printk(" ");
159 
160 	printk("  Model: ");
161 	for (i = 16; i < 32; i++)
162 		if (inq_result[i] >= 0x20 && i < inq_result[4] + 5)
163 			printk("%c", inq_result[i]);
164 		else
165 			printk(" ");
166 
167 	printk("  Rev: ");
168 	for (i = 32; i < 36; i++)
169 		if (inq_result[i] >= 0x20 && i < inq_result[4] + 5)
170 			printk("%c", inq_result[i]);
171 		else
172 			printk(" ");
173 
174 	printk("\n");
175 
176 	i = inq_result[0] & 0x1f;
177 
178 	printk(KERN_NOTICE "  Type:   %s ",
179 	       i <
180 	       MAX_SCSI_DEVICE_CODE ? scsi_device_types[i] :
181 	       "Unknown          ");
182 	printk("                 ANSI SCSI revision: %02x",
183 	       inq_result[2] & 0x07);
184 	if ((inq_result[2] & 0x07) == 1 && (inq_result[3] & 0x0f) == 1)
185 		printk(" CCS\n");
186 	else
187 		printk("\n");
188 }
189 
190 /**
191  * scsi_alloc_sdev - allocate and setup a scsi_Device
192  *
193  * Description:
194  *     Allocate, initialize for io, and return a pointer to a scsi_Device.
195  *     Stores the @shost, @channel, @id, and @lun in the scsi_Device, and
196  *     adds scsi_Device to the appropriate list.
197  *
198  * Return value:
199  *     scsi_Device pointer, or NULL on failure.
200  **/
201 static struct scsi_device *scsi_alloc_sdev(struct scsi_target *starget,
202 					   unsigned int lun, void *hostdata)
203 {
204 	struct scsi_device *sdev;
205 	int display_failure_msg = 1, ret;
206 	struct Scsi_Host *shost = dev_to_shost(starget->dev.parent);
207 
208 	sdev = kmalloc(sizeof(*sdev) + shost->transportt->device_size,
209 		       GFP_ATOMIC);
210 	if (!sdev)
211 		goto out;
212 
213 	memset(sdev, 0, sizeof(*sdev));
214 	sdev->vendor = scsi_null_device_strs;
215 	sdev->model = scsi_null_device_strs;
216 	sdev->rev = scsi_null_device_strs;
217 	sdev->host = shost;
218 	sdev->id = starget->id;
219 	sdev->lun = lun;
220 	sdev->channel = starget->channel;
221 	sdev->sdev_state = SDEV_CREATED;
222 	INIT_LIST_HEAD(&sdev->siblings);
223 	INIT_LIST_HEAD(&sdev->same_target_siblings);
224 	INIT_LIST_HEAD(&sdev->cmd_list);
225 	INIT_LIST_HEAD(&sdev->starved_entry);
226 	spin_lock_init(&sdev->list_lock);
227 
228 	sdev->sdev_gendev.parent = get_device(&starget->dev);
229 	sdev->sdev_target = starget;
230 
231 	/* usually NULL and set by ->slave_alloc instead */
232 	sdev->hostdata = hostdata;
233 
234 	/* if the device needs this changing, it may do so in the
235 	 * slave_configure function */
236 	sdev->max_device_blocked = SCSI_DEFAULT_DEVICE_BLOCKED;
237 
238 	/*
239 	 * Some low level driver could use device->type
240 	 */
241 	sdev->type = -1;
242 
243 	/*
244 	 * Assume that the device will have handshaking problems,
245 	 * and then fix this field later if it turns out it
246 	 * doesn't
247 	 */
248 	sdev->borken = 1;
249 
250 	sdev->request_queue = scsi_alloc_queue(sdev);
251 	if (!sdev->request_queue) {
252 		/* release fn is set up in scsi_sysfs_device_initialise, so
253 		 * have to free and put manually here */
254 		put_device(&starget->dev);
255 		goto out;
256 	}
257 
258 	sdev->request_queue->queuedata = sdev;
259 	scsi_adjust_queue_depth(sdev, 0, sdev->host->cmd_per_lun);
260 
261 	scsi_sysfs_device_initialize(sdev);
262 
263 	if (shost->hostt->slave_alloc) {
264 		ret = shost->hostt->slave_alloc(sdev);
265 		if (ret) {
266 			/*
267 			 * if LLDD reports slave not present, don't clutter
268 			 * console with alloc failure messages
269 			 */
270 			if (ret == -ENXIO)
271 				display_failure_msg = 0;
272 			goto out_device_destroy;
273 		}
274 	}
275 
276 	return sdev;
277 
278 out_device_destroy:
279 	transport_destroy_device(&sdev->sdev_gendev);
280 	put_device(&sdev->sdev_gendev);
281 out:
282 	if (display_failure_msg)
283 		printk(ALLOC_FAILURE_MSG, __FUNCTION__);
284 	return NULL;
285 }
286 
287 static void scsi_target_dev_release(struct device *dev)
288 {
289 	struct device *parent = dev->parent;
290 	struct scsi_target *starget = to_scsi_target(dev);
291 	struct Scsi_Host *shost = dev_to_shost(parent);
292 
293 	if (shost->hostt->target_destroy)
294 		shost->hostt->target_destroy(starget);
295 	kfree(starget);
296 	put_device(parent);
297 }
298 
299 int scsi_is_target_device(const struct device *dev)
300 {
301 	return dev->release == scsi_target_dev_release;
302 }
303 EXPORT_SYMBOL(scsi_is_target_device);
304 
305 static struct scsi_target *__scsi_find_target(struct device *parent,
306 					      int channel, uint id)
307 {
308 	struct scsi_target *starget, *found_starget = NULL;
309 	struct Scsi_Host *shost = dev_to_shost(parent);
310 	/*
311 	 * Search for an existing target for this sdev.
312 	 */
313 	list_for_each_entry(starget, &shost->__targets, siblings) {
314 		if (starget->id == id &&
315 		    starget->channel == channel) {
316 			found_starget = starget;
317 			break;
318 		}
319 	}
320 	if (found_starget)
321 		get_device(&found_starget->dev);
322 
323 	return found_starget;
324 }
325 
326 static struct scsi_target *scsi_alloc_target(struct device *parent,
327 					     int channel, uint id)
328 {
329 	struct Scsi_Host *shost = dev_to_shost(parent);
330 	struct device *dev = NULL;
331 	unsigned long flags;
332 	const int size = sizeof(struct scsi_target)
333 		+ shost->transportt->target_size;
334 	struct scsi_target *starget;
335 	struct scsi_target *found_target;
336 
337 	/*
338 	 * Obtain the real parent from the transport. The transport
339 	 * is allowed to fail (no error) if there is nothing at that
340 	 * target id.
341 	 */
342 	if (shost->transportt->target_parent) {
343 		spin_lock_irqsave(shost->host_lock, flags);
344 		parent = shost->transportt->target_parent(shost, channel, id);
345 		spin_unlock_irqrestore(shost->host_lock, flags);
346 		if (!parent)
347 			return NULL;
348 	}
349 
350 	starget = kmalloc(size, GFP_KERNEL);
351 	if (!starget) {
352 		printk(KERN_ERR "%s: allocation failure\n", __FUNCTION__);
353 		return NULL;
354 	}
355 	memset(starget, 0, size);
356 	dev = &starget->dev;
357 	device_initialize(dev);
358 	starget->reap_ref = 1;
359 	dev->parent = get_device(parent);
360 	dev->release = scsi_target_dev_release;
361 	sprintf(dev->bus_id, "target%d:%d:%d",
362 		shost->host_no, channel, id);
363 	starget->id = id;
364 	starget->channel = channel;
365 	INIT_LIST_HEAD(&starget->siblings);
366 	INIT_LIST_HEAD(&starget->devices);
367 	spin_lock_irqsave(shost->host_lock, flags);
368 
369 	found_target = __scsi_find_target(parent, channel, id);
370 	if (found_target)
371 		goto found;
372 
373 	list_add_tail(&starget->siblings, &shost->__targets);
374 	spin_unlock_irqrestore(shost->host_lock, flags);
375 	/* allocate and add */
376 	transport_setup_device(dev);
377 	device_add(dev);
378 	transport_add_device(dev);
379 	if (shost->hostt->target_alloc) {
380 		int error = shost->hostt->target_alloc(starget);
381 
382 		if(error) {
383 			dev_printk(KERN_ERR, dev, "target allocation failed, error %d\n", error);
384 			/* don't want scsi_target_reap to do the final
385 			 * put because it will be under the host lock */
386 			get_device(dev);
387 			scsi_target_reap(starget);
388 			put_device(dev);
389 			return NULL;
390 		}
391 	}
392 
393 	return starget;
394 
395  found:
396 	found_target->reap_ref++;
397 	spin_unlock_irqrestore(shost->host_lock, flags);
398 	put_device(parent);
399 	kfree(starget);
400 	return found_target;
401 }
402 
403 struct work_queue_wrapper {
404 	struct work_struct	work;
405 	struct scsi_target	*starget;
406 };
407 
408 static void scsi_target_reap_work(void *data) {
409 	struct work_queue_wrapper *wqw = (struct work_queue_wrapper *)data;
410 	struct scsi_target *starget = wqw->starget;
411 	struct Scsi_Host *shost = dev_to_shost(starget->dev.parent);
412 	unsigned long flags;
413 
414 	kfree(wqw);
415 
416 	spin_lock_irqsave(shost->host_lock, flags);
417 
418 	if (--starget->reap_ref == 0 && list_empty(&starget->devices)) {
419 		list_del_init(&starget->siblings);
420 		spin_unlock_irqrestore(shost->host_lock, flags);
421 		device_del(&starget->dev);
422 		transport_unregister_device(&starget->dev);
423 		put_device(&starget->dev);
424 		return;
425 
426 	}
427 	spin_unlock_irqrestore(shost->host_lock, flags);
428 
429 	return;
430 }
431 
432 /**
433  * scsi_target_reap - check to see if target is in use and destroy if not
434  *
435  * @starget: target to be checked
436  *
437  * This is used after removing a LUN or doing a last put of the target
438  * it checks atomically that nothing is using the target and removes
439  * it if so.
440  */
441 void scsi_target_reap(struct scsi_target *starget)
442 {
443 	struct work_queue_wrapper *wqw =
444 		kzalloc(sizeof(struct work_queue_wrapper), GFP_ATOMIC);
445 
446 	if (!wqw) {
447 		starget_printk(KERN_ERR, starget,
448 			       "Failed to allocate memory in scsi_reap_target()\n");
449 		return;
450 	}
451 
452 	INIT_WORK(&wqw->work, scsi_target_reap_work, wqw);
453 	wqw->starget = starget;
454 	schedule_work(&wqw->work);
455 }
456 
457 /**
458  * scsi_probe_lun - probe a single LUN using a SCSI INQUIRY
459  * @sdev:	scsi_device to probe
460  * @inq_result:	area to store the INQUIRY result
461  * @result_len: len of inq_result
462  * @bflags:	store any bflags found here
463  *
464  * Description:
465  *     Probe the lun associated with @req using a standard SCSI INQUIRY;
466  *
467  *     If the INQUIRY is successful, zero is returned and the
468  *     INQUIRY data is in @inq_result; the scsi_level and INQUIRY length
469  *     are copied to the scsi_device any flags value is stored in *@bflags.
470  **/
471 static int scsi_probe_lun(struct scsi_device *sdev, char *inq_result,
472 			  int result_len, int *bflags)
473 {
474 	unsigned char scsi_cmd[MAX_COMMAND_SIZE];
475 	int first_inquiry_len, try_inquiry_len, next_inquiry_len;
476 	int response_len = 0;
477 	int pass, count, result;
478 	struct scsi_sense_hdr sshdr;
479 
480 	*bflags = 0;
481 
482 	/* Perform up to 3 passes.  The first pass uses a conservative
483 	 * transfer length of 36 unless sdev->inquiry_len specifies a
484 	 * different value. */
485 	first_inquiry_len = sdev->inquiry_len ? sdev->inquiry_len : 36;
486 	try_inquiry_len = first_inquiry_len;
487 	pass = 1;
488 
489  next_pass:
490 	SCSI_LOG_SCAN_BUS(3, sdev_printk(KERN_INFO, sdev,
491 				"scsi scan: INQUIRY pass %d length %d\n",
492 				pass, try_inquiry_len));
493 
494 	/* Each pass gets up to three chances to ignore Unit Attention */
495 	for (count = 0; count < 3; ++count) {
496 		memset(scsi_cmd, 0, 6);
497 		scsi_cmd[0] = INQUIRY;
498 		scsi_cmd[4] = (unsigned char) try_inquiry_len;
499 
500 		memset(inq_result, 0, try_inquiry_len);
501 
502 		result = scsi_execute_req(sdev,  scsi_cmd, DMA_FROM_DEVICE,
503 					  inq_result, try_inquiry_len, &sshdr,
504 					  HZ / 2 + HZ * scsi_inq_timeout, 3);
505 
506 		SCSI_LOG_SCAN_BUS(3, printk(KERN_INFO "scsi scan: INQUIRY %s "
507 				"with code 0x%x\n",
508 				result ? "failed" : "successful", result));
509 
510 		if (result) {
511 			/*
512 			 * not-ready to ready transition [asc/ascq=0x28/0x0]
513 			 * or power-on, reset [asc/ascq=0x29/0x0], continue.
514 			 * INQUIRY should not yield UNIT_ATTENTION
515 			 * but many buggy devices do so anyway.
516 			 */
517 			if ((driver_byte(result) & DRIVER_SENSE) &&
518 			    scsi_sense_valid(&sshdr)) {
519 				if ((sshdr.sense_key == UNIT_ATTENTION) &&
520 				    ((sshdr.asc == 0x28) ||
521 				     (sshdr.asc == 0x29)) &&
522 				    (sshdr.ascq == 0))
523 					continue;
524 			}
525 		}
526 		break;
527 	}
528 
529 	if (result == 0) {
530 		response_len = (unsigned char) inq_result[4] + 5;
531 		if (response_len > 255)
532 			response_len = first_inquiry_len;	/* sanity */
533 
534 		/*
535 		 * Get any flags for this device.
536 		 *
537 		 * XXX add a bflags to scsi_device, and replace the
538 		 * corresponding bit fields in scsi_device, so bflags
539 		 * need not be passed as an argument.
540 		 */
541 		*bflags = scsi_get_device_flags(sdev, &inq_result[8],
542 				&inq_result[16]);
543 
544 		/* When the first pass succeeds we gain information about
545 		 * what larger transfer lengths might work. */
546 		if (pass == 1) {
547 			if (BLIST_INQUIRY_36 & *bflags)
548 				next_inquiry_len = 36;
549 			else if (BLIST_INQUIRY_58 & *bflags)
550 				next_inquiry_len = 58;
551 			else if (sdev->inquiry_len)
552 				next_inquiry_len = sdev->inquiry_len;
553 			else
554 				next_inquiry_len = response_len;
555 
556 			/* If more data is available perform the second pass */
557 			if (next_inquiry_len > try_inquiry_len) {
558 				try_inquiry_len = next_inquiry_len;
559 				pass = 2;
560 				goto next_pass;
561 			}
562 		}
563 
564 	} else if (pass == 2) {
565 		printk(KERN_INFO "scsi scan: %d byte inquiry failed.  "
566 				"Consider BLIST_INQUIRY_36 for this device\n",
567 				try_inquiry_len);
568 
569 		/* If this pass failed, the third pass goes back and transfers
570 		 * the same amount as we successfully got in the first pass. */
571 		try_inquiry_len = first_inquiry_len;
572 		pass = 3;
573 		goto next_pass;
574 	}
575 
576 	/* If the last transfer attempt got an error, assume the
577 	 * peripheral doesn't exist or is dead. */
578 	if (result)
579 		return -EIO;
580 
581 	/* Don't report any more data than the device says is valid */
582 	sdev->inquiry_len = min(try_inquiry_len, response_len);
583 
584 	/*
585 	 * XXX Abort if the response length is less than 36? If less than
586 	 * 32, the lookup of the device flags (above) could be invalid,
587 	 * and it would be possible to take an incorrect action - we do
588 	 * not want to hang because of a short INQUIRY. On the flip side,
589 	 * if the device is spun down or becoming ready (and so it gives a
590 	 * short INQUIRY), an abort here prevents any further use of the
591 	 * device, including spin up.
592 	 *
593 	 * Related to the above issue:
594 	 *
595 	 * XXX Devices (disk or all?) should be sent a TEST UNIT READY,
596 	 * and if not ready, sent a START_STOP to start (maybe spin up) and
597 	 * then send the INQUIRY again, since the INQUIRY can change after
598 	 * a device is initialized.
599 	 *
600 	 * Ideally, start a device if explicitly asked to do so.  This
601 	 * assumes that a device is spun up on power on, spun down on
602 	 * request, and then spun up on request.
603 	 */
604 
605 	/*
606 	 * The scanning code needs to know the scsi_level, even if no
607 	 * device is attached at LUN 0 (SCSI_SCAN_TARGET_PRESENT) so
608 	 * non-zero LUNs can be scanned.
609 	 */
610 	sdev->scsi_level = inq_result[2] & 0x07;
611 	if (sdev->scsi_level >= 2 ||
612 	    (sdev->scsi_level == 1 && (inq_result[3] & 0x0f) == 1))
613 		sdev->scsi_level++;
614 	sdev->sdev_target->scsi_level = sdev->scsi_level;
615 
616 	return 0;
617 }
618 
619 /**
620  * scsi_add_lun - allocate and fully initialze a scsi_device
621  * @sdevscan:	holds information to be stored in the new scsi_device
622  * @sdevnew:	store the address of the newly allocated scsi_device
623  * @inq_result:	holds the result of a previous INQUIRY to the LUN
624  * @bflags:	black/white list flag
625  *
626  * Description:
627  *     Allocate and initialize a scsi_device matching sdevscan. Optionally
628  *     set fields based on values in *@bflags. If @sdevnew is not
629  *     NULL, store the address of the new scsi_device in *@sdevnew (needed
630  *     when scanning a particular LUN).
631  *
632  * Return:
633  *     SCSI_SCAN_NO_RESPONSE: could not allocate or setup a scsi_device
634  *     SCSI_SCAN_LUN_PRESENT: a new scsi_device was allocated and initialized
635  **/
636 static int scsi_add_lun(struct scsi_device *sdev, char *inq_result, int *bflags)
637 {
638 	/*
639 	 * XXX do not save the inquiry, since it can change underneath us,
640 	 * save just vendor/model/rev.
641 	 *
642 	 * Rather than save it and have an ioctl that retrieves the saved
643 	 * value, have an ioctl that executes the same INQUIRY code used
644 	 * in scsi_probe_lun, let user level programs doing INQUIRY
645 	 * scanning run at their own risk, or supply a user level program
646 	 * that can correctly scan.
647 	 */
648 	sdev->inquiry = kmalloc(sdev->inquiry_len, GFP_ATOMIC);
649 	if (sdev->inquiry == NULL) {
650 		return SCSI_SCAN_NO_RESPONSE;
651 	}
652 
653 	memcpy(sdev->inquiry, inq_result, sdev->inquiry_len);
654 	sdev->vendor = (char *) (sdev->inquiry + 8);
655 	sdev->model = (char *) (sdev->inquiry + 16);
656 	sdev->rev = (char *) (sdev->inquiry + 32);
657 
658 	if (*bflags & BLIST_ISROM) {
659 		/*
660 		 * It would be better to modify sdev->type, and set
661 		 * sdev->removable, but then the print_inquiry() output
662 		 * would not show TYPE_ROM; if print_inquiry() is removed
663 		 * the issue goes away.
664 		 */
665 		inq_result[0] = TYPE_ROM;
666 		inq_result[1] |= 0x80;	/* removable */
667 	} else if (*bflags & BLIST_NO_ULD_ATTACH)
668 		sdev->no_uld_attach = 1;
669 
670 	switch (sdev->type = (inq_result[0] & 0x1f)) {
671 	case TYPE_TAPE:
672 	case TYPE_DISK:
673 	case TYPE_PRINTER:
674 	case TYPE_MOD:
675 	case TYPE_PROCESSOR:
676 	case TYPE_SCANNER:
677 	case TYPE_MEDIUM_CHANGER:
678 	case TYPE_ENCLOSURE:
679 	case TYPE_COMM:
680 	case TYPE_RBC:
681 		sdev->writeable = 1;
682 		break;
683 	case TYPE_WORM:
684 	case TYPE_ROM:
685 		sdev->writeable = 0;
686 		break;
687 	default:
688 		printk(KERN_INFO "scsi: unknown device type %d\n", sdev->type);
689 	}
690 
691 	print_inquiry(inq_result);
692 
693 	/*
694 	 * For a peripheral qualifier (PQ) value of 1 (001b), the SCSI
695 	 * spec says: The device server is capable of supporting the
696 	 * specified peripheral device type on this logical unit. However,
697 	 * the physical device is not currently connected to this logical
698 	 * unit.
699 	 *
700 	 * The above is vague, as it implies that we could treat 001 and
701 	 * 011 the same. Stay compatible with previous code, and create a
702 	 * scsi_device for a PQ of 1
703 	 *
704 	 * Don't set the device offline here; rather let the upper
705 	 * level drivers eval the PQ to decide whether they should
706 	 * attach. So remove ((inq_result[0] >> 5) & 7) == 1 check.
707 	 */
708 
709 	sdev->inq_periph_qual = (inq_result[0] >> 5) & 7;
710 	sdev->removable = (0x80 & inq_result[1]) >> 7;
711 	sdev->lockable = sdev->removable;
712 	sdev->soft_reset = (inq_result[7] & 1) && ((inq_result[3] & 7) == 2);
713 
714 	if (sdev->scsi_level >= SCSI_3 || (sdev->inquiry_len > 56 &&
715 		inq_result[56] & 0x04))
716 		sdev->ppr = 1;
717 	if (inq_result[7] & 0x60)
718 		sdev->wdtr = 1;
719 	if (inq_result[7] & 0x10)
720 		sdev->sdtr = 1;
721 
722 	sprintf(sdev->devfs_name, "scsi/host%d/bus%d/target%d/lun%d",
723 				sdev->host->host_no, sdev->channel,
724 				sdev->id, sdev->lun);
725 
726 	/*
727 	 * End driverfs/devfs code.
728 	 */
729 
730 	if ((sdev->scsi_level >= SCSI_2) && (inq_result[7] & 2) &&
731 	    !(*bflags & BLIST_NOTQ))
732 		sdev->tagged_supported = 1;
733 	/*
734 	 * Some devices (Texel CD ROM drives) have handshaking problems
735 	 * when used with the Seagate controllers. borken is initialized
736 	 * to 1, and then set it to 0 here.
737 	 */
738 	if ((*bflags & BLIST_BORKEN) == 0)
739 		sdev->borken = 0;
740 
741 	/*
742 	 * Apparently some really broken devices (contrary to the SCSI
743 	 * standards) need to be selected without asserting ATN
744 	 */
745 	if (*bflags & BLIST_SELECT_NO_ATN)
746 		sdev->select_no_atn = 1;
747 
748 	/*
749 	 * Some devices may not want to have a start command automatically
750 	 * issued when a device is added.
751 	 */
752 	if (*bflags & BLIST_NOSTARTONADD)
753 		sdev->no_start_on_add = 1;
754 
755 	if (*bflags & BLIST_SINGLELUN)
756 		sdev->single_lun = 1;
757 
758 
759 	sdev->use_10_for_rw = 1;
760 
761 	if (*bflags & BLIST_MS_SKIP_PAGE_08)
762 		sdev->skip_ms_page_8 = 1;
763 
764 	if (*bflags & BLIST_MS_SKIP_PAGE_3F)
765 		sdev->skip_ms_page_3f = 1;
766 
767 	if (*bflags & BLIST_USE_10_BYTE_MS)
768 		sdev->use_10_for_ms = 1;
769 
770 	/* set the device running here so that slave configure
771 	 * may do I/O */
772 	scsi_device_set_state(sdev, SDEV_RUNNING);
773 
774 	if (*bflags & BLIST_MS_192_BYTES_FOR_3F)
775 		sdev->use_192_bytes_for_3f = 1;
776 
777 	if (*bflags & BLIST_NOT_LOCKABLE)
778 		sdev->lockable = 0;
779 
780 	if (*bflags & BLIST_RETRY_HWERROR)
781 		sdev->retry_hwerror = 1;
782 
783 	transport_configure_device(&sdev->sdev_gendev);
784 
785 	if (sdev->host->hostt->slave_configure)
786 		sdev->host->hostt->slave_configure(sdev);
787 
788 	/*
789 	 * Ok, the device is now all set up, we can
790 	 * register it and tell the rest of the kernel
791 	 * about it.
792 	 */
793 	if (scsi_sysfs_add_sdev(sdev) != 0)
794 		return SCSI_SCAN_NO_RESPONSE;
795 
796 	return SCSI_SCAN_LUN_PRESENT;
797 }
798 
799 static inline void scsi_destroy_sdev(struct scsi_device *sdev)
800 {
801 	if (sdev->host->hostt->slave_destroy)
802 		sdev->host->hostt->slave_destroy(sdev);
803 	transport_destroy_device(&sdev->sdev_gendev);
804 	put_device(&sdev->sdev_gendev);
805 }
806 
807 
808 /**
809  * scsi_probe_and_add_lun - probe a LUN, if a LUN is found add it
810  * @starget:	pointer to target device structure
811  * @lun:	LUN of target device
812  * @sdevscan:	probe the LUN corresponding to this scsi_device
813  * @sdevnew:	store the value of any new scsi_device allocated
814  * @bflagsp:	store bflags here if not NULL
815  *
816  * Description:
817  *     Call scsi_probe_lun, if a LUN with an attached device is found,
818  *     allocate and set it up by calling scsi_add_lun.
819  *
820  * Return:
821  *     SCSI_SCAN_NO_RESPONSE: could not allocate or setup a scsi_device
822  *     SCSI_SCAN_TARGET_PRESENT: target responded, but no device is
823  *         attached at the LUN
824  *     SCSI_SCAN_LUN_PRESENT: a new scsi_device was allocated and initialized
825  **/
826 static int scsi_probe_and_add_lun(struct scsi_target *starget,
827 				  uint lun, int *bflagsp,
828 				  struct scsi_device **sdevp, int rescan,
829 				  void *hostdata)
830 {
831 	struct scsi_device *sdev;
832 	unsigned char *result;
833 	int bflags, res = SCSI_SCAN_NO_RESPONSE, result_len = 256;
834 	struct Scsi_Host *shost = dev_to_shost(starget->dev.parent);
835 
836 	/*
837 	 * The rescan flag is used as an optimization, the first scan of a
838 	 * host adapter calls into here with rescan == 0.
839 	 */
840 	sdev = scsi_device_lookup_by_target(starget, lun);
841 	if (sdev) {
842 		if (rescan || sdev->sdev_state != SDEV_CREATED) {
843 			SCSI_LOG_SCAN_BUS(3, printk(KERN_INFO
844 				"scsi scan: device exists on %s\n",
845 				sdev->sdev_gendev.bus_id));
846 			if (sdevp)
847 				*sdevp = sdev;
848 			else
849 				scsi_device_put(sdev);
850 
851 			if (bflagsp)
852 				*bflagsp = scsi_get_device_flags(sdev,
853 								 sdev->vendor,
854 								 sdev->model);
855 			return SCSI_SCAN_LUN_PRESENT;
856 		}
857 		scsi_device_put(sdev);
858 	} else
859 		sdev = scsi_alloc_sdev(starget, lun, hostdata);
860 	if (!sdev)
861 		goto out;
862 
863 	result = kmalloc(result_len, GFP_ATOMIC |
864 			((shost->unchecked_isa_dma) ? __GFP_DMA : 0));
865 	if (!result)
866 		goto out_free_sdev;
867 
868 	if (scsi_probe_lun(sdev, result, result_len, &bflags))
869 		goto out_free_result;
870 
871 	/*
872 	 * result contains valid SCSI INQUIRY data.
873 	 */
874 	if ((result[0] >> 5) == 3) {
875 		/*
876 		 * For a Peripheral qualifier 3 (011b), the SCSI
877 		 * spec says: The device server is not capable of
878 		 * supporting a physical device on this logical
879 		 * unit.
880 		 *
881 		 * For disks, this implies that there is no
882 		 * logical disk configured at sdev->lun, but there
883 		 * is a target id responding.
884 		 */
885 		SCSI_LOG_SCAN_BUS(3, printk(KERN_INFO
886 					"scsi scan: peripheral qualifier of 3,"
887 					" no device added\n"));
888 		res = SCSI_SCAN_TARGET_PRESENT;
889 		goto out_free_result;
890 	}
891 
892 	res = scsi_add_lun(sdev, result, &bflags);
893 	if (res == SCSI_SCAN_LUN_PRESENT) {
894 		if (bflags & BLIST_KEY) {
895 			sdev->lockable = 0;
896 			scsi_unlock_floptical(sdev, result);
897 		}
898 		if (bflagsp)
899 			*bflagsp = bflags;
900 	}
901 
902  out_free_result:
903 	kfree(result);
904  out_free_sdev:
905 	if (res == SCSI_SCAN_LUN_PRESENT) {
906 		if (sdevp) {
907 			if (scsi_device_get(sdev) == 0) {
908 				*sdevp = sdev;
909 			} else {
910 				__scsi_remove_device(sdev);
911 				res = SCSI_SCAN_NO_RESPONSE;
912 			}
913 		}
914 	} else
915 		scsi_destroy_sdev(sdev);
916  out:
917 	return res;
918 }
919 
920 /**
921  * scsi_sequential_lun_scan - sequentially scan a SCSI target
922  * @starget:	pointer to target structure to scan
923  * @bflags:	black/white list flag for LUN 0
924  * @lun0_res:	result of scanning LUN 0
925  *
926  * Description:
927  *     Generally, scan from LUN 1 (LUN 0 is assumed to already have been
928  *     scanned) to some maximum lun until a LUN is found with no device
929  *     attached. Use the bflags to figure out any oddities.
930  *
931  *     Modifies sdevscan->lun.
932  **/
933 static void scsi_sequential_lun_scan(struct scsi_target *starget,
934 				     int bflags, int lun0_res, int scsi_level,
935 				     int rescan)
936 {
937 	unsigned int sparse_lun, lun, max_dev_lun;
938 	struct Scsi_Host *shost = dev_to_shost(starget->dev.parent);
939 
940 	SCSI_LOG_SCAN_BUS(3, printk(KERN_INFO "scsi scan: Sequential scan of"
941 				    "%s\n", starget->dev.bus_id));
942 
943 	max_dev_lun = min(max_scsi_luns, shost->max_lun);
944 	/*
945 	 * If this device is known to support sparse multiple units,
946 	 * override the other settings, and scan all of them. Normally,
947 	 * SCSI-3 devices should be scanned via the REPORT LUNS.
948 	 */
949 	if (bflags & BLIST_SPARSELUN) {
950 		max_dev_lun = shost->max_lun;
951 		sparse_lun = 1;
952 	} else
953 		sparse_lun = 0;
954 
955 	/*
956 	 * If not sparse lun and no device attached at LUN 0 do not scan
957 	 * any further.
958 	 */
959 	if (!sparse_lun && (lun0_res != SCSI_SCAN_LUN_PRESENT))
960 		return;
961 
962 	/*
963 	 * If less than SCSI_1_CSS, and no special lun scaning, stop
964 	 * scanning; this matches 2.4 behaviour, but could just be a bug
965 	 * (to continue scanning a SCSI_1_CSS device).
966 	 *
967 	 * This test is broken.  We might not have any device on lun0 for
968 	 * a sparselun device, and if that's the case then how would we
969 	 * know the real scsi_level, eh?  It might make sense to just not
970 	 * scan any SCSI_1 device for non-0 luns, but that check would best
971 	 * go into scsi_alloc_sdev() and just have it return null when asked
972 	 * to alloc an sdev for lun > 0 on an already found SCSI_1 device.
973 	 *
974 	if ((sdevscan->scsi_level < SCSI_1_CCS) &&
975 	    ((bflags & (BLIST_FORCELUN | BLIST_SPARSELUN | BLIST_MAX5LUN))
976 	     == 0))
977 		return;
978 	 */
979 	/*
980 	 * If this device is known to support multiple units, override
981 	 * the other settings, and scan all of them.
982 	 */
983 	if (bflags & BLIST_FORCELUN)
984 		max_dev_lun = shost->max_lun;
985 	/*
986 	 * REGAL CDC-4X: avoid hang after LUN 4
987 	 */
988 	if (bflags & BLIST_MAX5LUN)
989 		max_dev_lun = min(5U, max_dev_lun);
990 	/*
991 	 * Do not scan SCSI-2 or lower device past LUN 7, unless
992 	 * BLIST_LARGELUN.
993 	 */
994 	if (scsi_level < SCSI_3 && !(bflags & BLIST_LARGELUN))
995 		max_dev_lun = min(8U, max_dev_lun);
996 
997 	/*
998 	 * We have already scanned LUN 0, so start at LUN 1. Keep scanning
999 	 * until we reach the max, or no LUN is found and we are not
1000 	 * sparse_lun.
1001 	 */
1002 	for (lun = 1; lun < max_dev_lun; ++lun)
1003 		if ((scsi_probe_and_add_lun(starget, lun, NULL, NULL, rescan,
1004 					    NULL) != SCSI_SCAN_LUN_PRESENT) &&
1005 		    !sparse_lun)
1006 			return;
1007 }
1008 
1009 /**
1010  * scsilun_to_int: convert a scsi_lun to an int
1011  * @scsilun:	struct scsi_lun to be converted.
1012  *
1013  * Description:
1014  *     Convert @scsilun from a struct scsi_lun to a four byte host byte-ordered
1015  *     integer, and return the result. The caller must check for
1016  *     truncation before using this function.
1017  *
1018  * Notes:
1019  *     The struct scsi_lun is assumed to be four levels, with each level
1020  *     effectively containing a SCSI byte-ordered (big endian) short; the
1021  *     addressing bits of each level are ignored (the highest two bits).
1022  *     For a description of the LUN format, post SCSI-3 see the SCSI
1023  *     Architecture Model, for SCSI-3 see the SCSI Controller Commands.
1024  *
1025  *     Given a struct scsi_lun of: 0a 04 0b 03 00 00 00 00, this function returns
1026  *     the integer: 0x0b030a04
1027  **/
1028 static int scsilun_to_int(struct scsi_lun *scsilun)
1029 {
1030 	int i;
1031 	unsigned int lun;
1032 
1033 	lun = 0;
1034 	for (i = 0; i < sizeof(lun); i += 2)
1035 		lun = lun | (((scsilun->scsi_lun[i] << 8) |
1036 			      scsilun->scsi_lun[i + 1]) << (i * 8));
1037 	return lun;
1038 }
1039 
1040 /**
1041  * int_to_scsilun: reverts an int into a scsi_lun
1042  * @int:        integer to be reverted
1043  * @scsilun:	struct scsi_lun to be set.
1044  *
1045  * Description:
1046  *     Reverts the functionality of the scsilun_to_int, which packed
1047  *     an 8-byte lun value into an int. This routine unpacks the int
1048  *     back into the lun value.
1049  *     Note: the scsilun_to_int() routine does not truly handle all
1050  *     8bytes of the lun value. This functions restores only as much
1051  *     as was set by the routine.
1052  *
1053  * Notes:
1054  *     Given an integer : 0x0b030a04,  this function returns a
1055  *     scsi_lun of : struct scsi_lun of: 0a 04 0b 03 00 00 00 00
1056  *
1057  **/
1058 void int_to_scsilun(unsigned int lun, struct scsi_lun *scsilun)
1059 {
1060 	int i;
1061 
1062 	memset(scsilun->scsi_lun, 0, sizeof(scsilun->scsi_lun));
1063 
1064 	for (i = 0; i < sizeof(lun); i += 2) {
1065 		scsilun->scsi_lun[i] = (lun >> 8) & 0xFF;
1066 		scsilun->scsi_lun[i+1] = lun & 0xFF;
1067 		lun = lun >> 16;
1068 	}
1069 }
1070 EXPORT_SYMBOL(int_to_scsilun);
1071 
1072 /**
1073  * scsi_report_lun_scan - Scan using SCSI REPORT LUN results
1074  * @sdevscan:	scan the host, channel, and id of this scsi_device
1075  *
1076  * Description:
1077  *     If @sdevscan is for a SCSI-3 or up device, send a REPORT LUN
1078  *     command, and scan the resulting list of LUNs by calling
1079  *     scsi_probe_and_add_lun.
1080  *
1081  *     Modifies sdevscan->lun.
1082  *
1083  * Return:
1084  *     0: scan completed (or no memory, so further scanning is futile)
1085  *     1: no report lun scan, or not configured
1086  **/
1087 static int scsi_report_lun_scan(struct scsi_target *starget, int bflags,
1088 				int rescan)
1089 {
1090 	char devname[64];
1091 	unsigned char scsi_cmd[MAX_COMMAND_SIZE];
1092 	unsigned int length;
1093 	unsigned int lun;
1094 	unsigned int num_luns;
1095 	unsigned int retries;
1096 	int result;
1097 	struct scsi_lun *lunp, *lun_data;
1098 	u8 *data;
1099 	struct scsi_sense_hdr sshdr;
1100 	struct scsi_device *sdev;
1101 	struct Scsi_Host *shost = dev_to_shost(&starget->dev);
1102 	int ret = 0;
1103 
1104 	/*
1105 	 * Only support SCSI-3 and up devices if BLIST_NOREPORTLUN is not set.
1106 	 * Also allow SCSI-2 if BLIST_REPORTLUN2 is set and host adapter does
1107 	 * support more than 8 LUNs.
1108 	 */
1109 	if ((bflags & BLIST_NOREPORTLUN) ||
1110 	     starget->scsi_level < SCSI_2 ||
1111 	    (starget->scsi_level < SCSI_3 &&
1112 	     (!(bflags & BLIST_REPORTLUN2) || shost->max_lun <= 8)) )
1113 		return 1;
1114 	if (bflags & BLIST_NOLUN)
1115 		return 0;
1116 
1117 	if (!(sdev = scsi_device_lookup_by_target(starget, 0))) {
1118 		sdev = scsi_alloc_sdev(starget, 0, NULL);
1119 		if (!sdev)
1120 			return 0;
1121 		if (scsi_device_get(sdev))
1122 			return 0;
1123 	}
1124 
1125 	sprintf(devname, "host %d channel %d id %d",
1126 		shost->host_no, sdev->channel, sdev->id);
1127 
1128 	/*
1129 	 * Allocate enough to hold the header (the same size as one scsi_lun)
1130 	 * plus the max number of luns we are requesting.
1131 	 *
1132 	 * Reallocating and trying again (with the exact amount we need)
1133 	 * would be nice, but then we need to somehow limit the size
1134 	 * allocated based on the available memory and the limits of
1135 	 * kmalloc - we don't want a kmalloc() failure of a huge value to
1136 	 * prevent us from finding any LUNs on this target.
1137 	 */
1138 	length = (max_scsi_report_luns + 1) * sizeof(struct scsi_lun);
1139 	lun_data = kmalloc(length, GFP_ATOMIC |
1140 			   (sdev->host->unchecked_isa_dma ? __GFP_DMA : 0));
1141 	if (!lun_data) {
1142 		printk(ALLOC_FAILURE_MSG, __FUNCTION__);
1143 		goto out;
1144 	}
1145 
1146 	scsi_cmd[0] = REPORT_LUNS;
1147 
1148 	/*
1149 	 * bytes 1 - 5: reserved, set to zero.
1150 	 */
1151 	memset(&scsi_cmd[1], 0, 5);
1152 
1153 	/*
1154 	 * bytes 6 - 9: length of the command.
1155 	 */
1156 	scsi_cmd[6] = (unsigned char) (length >> 24) & 0xff;
1157 	scsi_cmd[7] = (unsigned char) (length >> 16) & 0xff;
1158 	scsi_cmd[8] = (unsigned char) (length >> 8) & 0xff;
1159 	scsi_cmd[9] = (unsigned char) length & 0xff;
1160 
1161 	scsi_cmd[10] = 0;	/* reserved */
1162 	scsi_cmd[11] = 0;	/* control */
1163 
1164 	/*
1165 	 * We can get a UNIT ATTENTION, for example a power on/reset, so
1166 	 * retry a few times (like sd.c does for TEST UNIT READY).
1167 	 * Experience shows some combinations of adapter/devices get at
1168 	 * least two power on/resets.
1169 	 *
1170 	 * Illegal requests (for devices that do not support REPORT LUNS)
1171 	 * should come through as a check condition, and will not generate
1172 	 * a retry.
1173 	 */
1174 	for (retries = 0; retries < 3; retries++) {
1175 		SCSI_LOG_SCAN_BUS(3, printk (KERN_INFO "scsi scan: Sending"
1176 				" REPORT LUNS to %s (try %d)\n", devname,
1177 				retries));
1178 
1179 		result = scsi_execute_req(sdev, scsi_cmd, DMA_FROM_DEVICE,
1180 					  lun_data, length, &sshdr,
1181 					  SCSI_TIMEOUT + 4 * HZ, 3);
1182 
1183 		SCSI_LOG_SCAN_BUS(3, printk (KERN_INFO "scsi scan: REPORT LUNS"
1184 				" %s (try %d) result 0x%x\n", result
1185 				?  "failed" : "successful", retries, result));
1186 		if (result == 0)
1187 			break;
1188 		else if (scsi_sense_valid(&sshdr)) {
1189 			if (sshdr.sense_key != UNIT_ATTENTION)
1190 				break;
1191 		}
1192 	}
1193 
1194 	if (result) {
1195 		/*
1196 		 * The device probably does not support a REPORT LUN command
1197 		 */
1198 		ret = 1;
1199 		goto out_err;
1200 	}
1201 
1202 	/*
1203 	 * Get the length from the first four bytes of lun_data.
1204 	 */
1205 	data = (u8 *) lun_data->scsi_lun;
1206 	length = ((data[0] << 24) | (data[1] << 16) |
1207 		  (data[2] << 8) | (data[3] << 0));
1208 
1209 	num_luns = (length / sizeof(struct scsi_lun));
1210 	if (num_luns > max_scsi_report_luns) {
1211 		printk(KERN_WARNING "scsi: On %s only %d (max_scsi_report_luns)"
1212 		       " of %d luns reported, try increasing"
1213 		       " max_scsi_report_luns.\n", devname,
1214 		       max_scsi_report_luns, num_luns);
1215 		num_luns = max_scsi_report_luns;
1216 	}
1217 
1218 	SCSI_LOG_SCAN_BUS(3, sdev_printk (KERN_INFO, sdev,
1219 		"scsi scan: REPORT LUN scan\n"));
1220 
1221 	/*
1222 	 * Scan the luns in lun_data. The entry at offset 0 is really
1223 	 * the header, so start at 1 and go up to and including num_luns.
1224 	 */
1225 	for (lunp = &lun_data[1]; lunp <= &lun_data[num_luns]; lunp++) {
1226 		lun = scsilun_to_int(lunp);
1227 
1228 		/*
1229 		 * Check if the unused part of lunp is non-zero, and so
1230 		 * does not fit in lun.
1231 		 */
1232 		if (memcmp(&lunp->scsi_lun[sizeof(lun)], "\0\0\0\0", 4)) {
1233 			int i;
1234 
1235 			/*
1236 			 * Output an error displaying the LUN in byte order,
1237 			 * this differs from what linux would print for the
1238 			 * integer LUN value.
1239 			 */
1240 			printk(KERN_WARNING "scsi: %s lun 0x", devname);
1241 			data = (char *)lunp->scsi_lun;
1242 			for (i = 0; i < sizeof(struct scsi_lun); i++)
1243 				printk("%02x", data[i]);
1244 			printk(" has a LUN larger than currently supported.\n");
1245 		} else if (lun > sdev->host->max_lun) {
1246 			printk(KERN_WARNING "scsi: %s lun%d has a LUN larger"
1247 			       " than allowed by the host adapter\n",
1248 			       devname, lun);
1249 		} else {
1250 			int res;
1251 
1252 			res = scsi_probe_and_add_lun(starget,
1253 				lun, NULL, NULL, rescan, NULL);
1254 			if (res == SCSI_SCAN_NO_RESPONSE) {
1255 				/*
1256 				 * Got some results, but now none, abort.
1257 				 */
1258 				sdev_printk(KERN_ERR, sdev,
1259 					"Unexpected response"
1260 				        " from lun %d while scanning, scan"
1261 				        " aborted\n", lun);
1262 				break;
1263 			}
1264 		}
1265 	}
1266 
1267  out_err:
1268 	kfree(lun_data);
1269  out:
1270 	scsi_device_put(sdev);
1271 	if (sdev->sdev_state == SDEV_CREATED)
1272 		/*
1273 		 * the sdev we used didn't appear in the report luns scan
1274 		 */
1275 		scsi_destroy_sdev(sdev);
1276 	return ret;
1277 }
1278 
1279 struct scsi_device *__scsi_add_device(struct Scsi_Host *shost, uint channel,
1280 				      uint id, uint lun, void *hostdata)
1281 {
1282 	struct scsi_device *sdev;
1283 	struct device *parent = &shost->shost_gendev;
1284 	int res;
1285 	struct scsi_target *starget = scsi_alloc_target(parent, channel, id);
1286 
1287 	if (!starget)
1288 		return ERR_PTR(-ENOMEM);
1289 
1290 	get_device(&starget->dev);
1291 	down(&shost->scan_mutex);
1292 	if (scsi_host_scan_allowed(shost)) {
1293 		res = scsi_probe_and_add_lun(starget, lun, NULL, &sdev, 1,
1294 					     hostdata);
1295 		if (res != SCSI_SCAN_LUN_PRESENT)
1296 			sdev = ERR_PTR(-ENODEV);
1297 	}
1298 	up(&shost->scan_mutex);
1299 	scsi_target_reap(starget);
1300 	put_device(&starget->dev);
1301 
1302 	return sdev;
1303 }
1304 EXPORT_SYMBOL(__scsi_add_device);
1305 
1306 int scsi_add_device(struct Scsi_Host *host, uint channel,
1307 		    uint target, uint lun)
1308 {
1309 	struct scsi_device *sdev =
1310 		__scsi_add_device(host, channel, target, lun, NULL);
1311 	if (IS_ERR(sdev))
1312 		return PTR_ERR(sdev);
1313 
1314 	scsi_device_put(sdev);
1315 	return 0;
1316 }
1317 EXPORT_SYMBOL(scsi_add_device);
1318 
1319 void scsi_rescan_device(struct device *dev)
1320 {
1321 	struct scsi_driver *drv;
1322 
1323 	if (!dev->driver)
1324 		return;
1325 
1326 	drv = to_scsi_driver(dev->driver);
1327 	if (try_module_get(drv->owner)) {
1328 		if (drv->rescan)
1329 			drv->rescan(dev);
1330 		module_put(drv->owner);
1331 	}
1332 }
1333 EXPORT_SYMBOL(scsi_rescan_device);
1334 
1335 static void __scsi_scan_target(struct device *parent, unsigned int channel,
1336 		unsigned int id, unsigned int lun, int rescan)
1337 {
1338 	struct Scsi_Host *shost = dev_to_shost(parent);
1339 	int bflags = 0;
1340 	int res;
1341 	struct scsi_target *starget;
1342 
1343 	if (shost->this_id == id)
1344 		/*
1345 		 * Don't scan the host adapter
1346 		 */
1347 		return;
1348 
1349 	starget = scsi_alloc_target(parent, channel, id);
1350 	if (!starget)
1351 		return;
1352 
1353 	get_device(&starget->dev);
1354 	if (lun != SCAN_WILD_CARD) {
1355 		/*
1356 		 * Scan for a specific host/chan/id/lun.
1357 		 */
1358 		scsi_probe_and_add_lun(starget, lun, NULL, NULL, rescan, NULL);
1359 		goto out_reap;
1360 	}
1361 
1362 	/*
1363 	 * Scan LUN 0, if there is some response, scan further. Ideally, we
1364 	 * would not configure LUN 0 until all LUNs are scanned.
1365 	 */
1366 	res = scsi_probe_and_add_lun(starget, 0, &bflags, NULL, rescan, NULL);
1367 	if (res == SCSI_SCAN_LUN_PRESENT || res == SCSI_SCAN_TARGET_PRESENT) {
1368 		if (scsi_report_lun_scan(starget, bflags, rescan) != 0)
1369 			/*
1370 			 * The REPORT LUN did not scan the target,
1371 			 * do a sequential scan.
1372 			 */
1373 			scsi_sequential_lun_scan(starget, bflags,
1374 				       	res, starget->scsi_level, rescan);
1375 	}
1376 
1377  out_reap:
1378 	/* now determine if the target has any children at all
1379 	 * and if not, nuke it */
1380 	scsi_target_reap(starget);
1381 
1382 	put_device(&starget->dev);
1383 }
1384 
1385 /**
1386  * scsi_scan_target - scan a target id, possibly including all LUNs on the
1387  *     target.
1388  * @parent:	host to scan
1389  * @channel:	channel to scan
1390  * @id:		target id to scan
1391  * @lun:	Specific LUN to scan or SCAN_WILD_CARD
1392  * @rescan:	passed to LUN scanning routines
1393  *
1394  * Description:
1395  *     Scan the target id on @parent, @channel, and @id. Scan at least LUN 0,
1396  *     and possibly all LUNs on the target id.
1397  *
1398  *     First try a REPORT LUN scan, if that does not scan the target, do a
1399  *     sequential scan of LUNs on the target id.
1400  **/
1401 void scsi_scan_target(struct device *parent, unsigned int channel,
1402 		      unsigned int id, unsigned int lun, int rescan)
1403 {
1404 	struct Scsi_Host *shost = dev_to_shost(parent);
1405 
1406 	down(&shost->scan_mutex);
1407 	if (scsi_host_scan_allowed(shost))
1408 		__scsi_scan_target(parent, channel, id, lun, rescan);
1409 	up(&shost->scan_mutex);
1410 }
1411 EXPORT_SYMBOL(scsi_scan_target);
1412 
1413 static void scsi_scan_channel(struct Scsi_Host *shost, unsigned int channel,
1414 			      unsigned int id, unsigned int lun, int rescan)
1415 {
1416 	uint order_id;
1417 
1418 	if (id == SCAN_WILD_CARD)
1419 		for (id = 0; id < shost->max_id; ++id) {
1420 			/*
1421 			 * XXX adapter drivers when possible (FCP, iSCSI)
1422 			 * could modify max_id to match the current max,
1423 			 * not the absolute max.
1424 			 *
1425 			 * XXX add a shost id iterator, so for example,
1426 			 * the FC ID can be the same as a target id
1427 			 * without a huge overhead of sparse id's.
1428 			 */
1429 			if (shost->reverse_ordering)
1430 				/*
1431 				 * Scan from high to low id.
1432 				 */
1433 				order_id = shost->max_id - id - 1;
1434 			else
1435 				order_id = id;
1436 			__scsi_scan_target(&shost->shost_gendev, channel,
1437 					order_id, lun, rescan);
1438 		}
1439 	else
1440 		__scsi_scan_target(&shost->shost_gendev, channel,
1441 				id, lun, rescan);
1442 }
1443 
1444 int scsi_scan_host_selected(struct Scsi_Host *shost, unsigned int channel,
1445 			    unsigned int id, unsigned int lun, int rescan)
1446 {
1447 	SCSI_LOG_SCAN_BUS(3, shost_printk (KERN_INFO, shost,
1448 		"%s: <%u:%u:%u>\n",
1449 		__FUNCTION__, channel, id, lun));
1450 
1451 	if (((channel != SCAN_WILD_CARD) && (channel > shost->max_channel)) ||
1452 	    ((id != SCAN_WILD_CARD) && (id > shost->max_id)) ||
1453 	    ((lun != SCAN_WILD_CARD) && (lun > shost->max_lun)))
1454 		return -EINVAL;
1455 
1456 	down(&shost->scan_mutex);
1457 	if (scsi_host_scan_allowed(shost)) {
1458 		if (channel == SCAN_WILD_CARD)
1459 			for (channel = 0; channel <= shost->max_channel;
1460 			     channel++)
1461 				scsi_scan_channel(shost, channel, id, lun,
1462 						  rescan);
1463 		else
1464 			scsi_scan_channel(shost, channel, id, lun, rescan);
1465 	}
1466 	up(&shost->scan_mutex);
1467 
1468 	return 0;
1469 }
1470 
1471 /**
1472  * scsi_scan_host - scan the given adapter
1473  * @shost:	adapter to scan
1474  **/
1475 void scsi_scan_host(struct Scsi_Host *shost)
1476 {
1477 	scsi_scan_host_selected(shost, SCAN_WILD_CARD, SCAN_WILD_CARD,
1478 				SCAN_WILD_CARD, 0);
1479 }
1480 EXPORT_SYMBOL(scsi_scan_host);
1481 
1482 void scsi_forget_host(struct Scsi_Host *shost)
1483 {
1484 	struct scsi_device *sdev;
1485 	unsigned long flags;
1486 
1487  restart:
1488 	spin_lock_irqsave(shost->host_lock, flags);
1489 	list_for_each_entry(sdev, &shost->__devices, siblings) {
1490 		if (sdev->sdev_state == SDEV_DEL)
1491 			continue;
1492 		spin_unlock_irqrestore(shost->host_lock, flags);
1493 		__scsi_remove_device(sdev);
1494 		goto restart;
1495 	}
1496 	spin_unlock_irqrestore(shost->host_lock, flags);
1497 }
1498 
1499 /*
1500  * Function:    scsi_get_host_dev()
1501  *
1502  * Purpose:     Create a scsi_device that points to the host adapter itself.
1503  *
1504  * Arguments:   SHpnt   - Host that needs a scsi_device
1505  *
1506  * Lock status: None assumed.
1507  *
1508  * Returns:     The scsi_device or NULL
1509  *
1510  * Notes:
1511  *	Attach a single scsi_device to the Scsi_Host - this should
1512  *	be made to look like a "pseudo-device" that points to the
1513  *	HA itself.
1514  *
1515  *	Note - this device is not accessible from any high-level
1516  *	drivers (including generics), which is probably not
1517  *	optimal.  We can add hooks later to attach
1518  */
1519 struct scsi_device *scsi_get_host_dev(struct Scsi_Host *shost)
1520 {
1521 	struct scsi_device *sdev = NULL;
1522 	struct scsi_target *starget;
1523 
1524 	down(&shost->scan_mutex);
1525 	if (!scsi_host_scan_allowed(shost))
1526 		goto out;
1527 	starget = scsi_alloc_target(&shost->shost_gendev, 0, shost->this_id);
1528 	if (!starget)
1529 		goto out;
1530 
1531 	sdev = scsi_alloc_sdev(starget, 0, NULL);
1532 	if (sdev) {
1533 		sdev->sdev_gendev.parent = get_device(&starget->dev);
1534 		sdev->borken = 0;
1535 	}
1536 	put_device(&starget->dev);
1537  out:
1538 	up(&shost->scan_mutex);
1539 	return sdev;
1540 }
1541 EXPORT_SYMBOL(scsi_get_host_dev);
1542 
1543 /*
1544  * Function:    scsi_free_host_dev()
1545  *
1546  * Purpose:     Free a scsi_device that points to the host adapter itself.
1547  *
1548  * Arguments:   SHpnt   - Host that needs a scsi_device
1549  *
1550  * Lock status: None assumed.
1551  *
1552  * Returns:     Nothing
1553  *
1554  * Notes:
1555  */
1556 void scsi_free_host_dev(struct scsi_device *sdev)
1557 {
1558 	BUG_ON(sdev->id != sdev->host->this_id);
1559 
1560 	scsi_destroy_sdev(sdev);
1561 }
1562 EXPORT_SYMBOL(scsi_free_host_dev);
1563 
1564