xref: /linux/drivers/scsi/scsi_scan.c (revision 87c2ce3b9305b9b723faeedf6e32ef703ec9b33a)
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 const 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 		transport_remove_device(&starget->dev);
422 		device_del(&starget->dev);
423 		transport_destroy_device(&starget->dev);
424 		put_device(&starget->dev);
425 		return;
426 
427 	}
428 	spin_unlock_irqrestore(shost->host_lock, flags);
429 
430 	return;
431 }
432 
433 /**
434  * scsi_target_reap - check to see if target is in use and destroy if not
435  *
436  * @starget: target to be checked
437  *
438  * This is used after removing a LUN or doing a last put of the target
439  * it checks atomically that nothing is using the target and removes
440  * it if so.
441  */
442 void scsi_target_reap(struct scsi_target *starget)
443 {
444 	struct work_queue_wrapper *wqw =
445 		kzalloc(sizeof(struct work_queue_wrapper), GFP_ATOMIC);
446 
447 	if (!wqw) {
448 		starget_printk(KERN_ERR, starget,
449 			       "Failed to allocate memory in scsi_reap_target()\n");
450 		return;
451 	}
452 
453 	INIT_WORK(&wqw->work, scsi_target_reap_work, wqw);
454 	wqw->starget = starget;
455 	schedule_work(&wqw->work);
456 }
457 
458 /**
459  * scsi_probe_lun - probe a single LUN using a SCSI INQUIRY
460  * @sdev:	scsi_device to probe
461  * @inq_result:	area to store the INQUIRY result
462  * @result_len: len of inq_result
463  * @bflags:	store any bflags found here
464  *
465  * Description:
466  *     Probe the lun associated with @req using a standard SCSI INQUIRY;
467  *
468  *     If the INQUIRY is successful, zero is returned and the
469  *     INQUIRY data is in @inq_result; the scsi_level and INQUIRY length
470  *     are copied to the scsi_device any flags value is stored in *@bflags.
471  **/
472 static int scsi_probe_lun(struct scsi_device *sdev, char *inq_result,
473 			  int result_len, int *bflags)
474 {
475 	unsigned char scsi_cmd[MAX_COMMAND_SIZE];
476 	int first_inquiry_len, try_inquiry_len, next_inquiry_len;
477 	int response_len = 0;
478 	int pass, count, result;
479 	struct scsi_sense_hdr sshdr;
480 
481 	*bflags = 0;
482 
483 	/* Perform up to 3 passes.  The first pass uses a conservative
484 	 * transfer length of 36 unless sdev->inquiry_len specifies a
485 	 * different value. */
486 	first_inquiry_len = sdev->inquiry_len ? sdev->inquiry_len : 36;
487 	try_inquiry_len = first_inquiry_len;
488 	pass = 1;
489 
490  next_pass:
491 	SCSI_LOG_SCAN_BUS(3, sdev_printk(KERN_INFO, sdev,
492 				"scsi scan: INQUIRY pass %d length %d\n",
493 				pass, try_inquiry_len));
494 
495 	/* Each pass gets up to three chances to ignore Unit Attention */
496 	for (count = 0; count < 3; ++count) {
497 		memset(scsi_cmd, 0, 6);
498 		scsi_cmd[0] = INQUIRY;
499 		scsi_cmd[4] = (unsigned char) try_inquiry_len;
500 
501 		memset(inq_result, 0, try_inquiry_len);
502 
503 		result = scsi_execute_req(sdev,  scsi_cmd, DMA_FROM_DEVICE,
504 					  inq_result, try_inquiry_len, &sshdr,
505 					  HZ / 2 + HZ * scsi_inq_timeout, 3);
506 
507 		SCSI_LOG_SCAN_BUS(3, printk(KERN_INFO "scsi scan: INQUIRY %s "
508 				"with code 0x%x\n",
509 				result ? "failed" : "successful", result));
510 
511 		if (result) {
512 			/*
513 			 * not-ready to ready transition [asc/ascq=0x28/0x0]
514 			 * or power-on, reset [asc/ascq=0x29/0x0], continue.
515 			 * INQUIRY should not yield UNIT_ATTENTION
516 			 * but many buggy devices do so anyway.
517 			 */
518 			if ((driver_byte(result) & DRIVER_SENSE) &&
519 			    scsi_sense_valid(&sshdr)) {
520 				if ((sshdr.sense_key == UNIT_ATTENTION) &&
521 				    ((sshdr.asc == 0x28) ||
522 				     (sshdr.asc == 0x29)) &&
523 				    (sshdr.ascq == 0))
524 					continue;
525 			}
526 		}
527 		break;
528 	}
529 
530 	if (result == 0) {
531 		response_len = (unsigned char) inq_result[4] + 5;
532 		if (response_len > 255)
533 			response_len = first_inquiry_len;	/* sanity */
534 
535 		/*
536 		 * Get any flags for this device.
537 		 *
538 		 * XXX add a bflags to scsi_device, and replace the
539 		 * corresponding bit fields in scsi_device, so bflags
540 		 * need not be passed as an argument.
541 		 */
542 		*bflags = scsi_get_device_flags(sdev, &inq_result[8],
543 				&inq_result[16]);
544 
545 		/* When the first pass succeeds we gain information about
546 		 * what larger transfer lengths might work. */
547 		if (pass == 1) {
548 			if (BLIST_INQUIRY_36 & *bflags)
549 				next_inquiry_len = 36;
550 			else if (BLIST_INQUIRY_58 & *bflags)
551 				next_inquiry_len = 58;
552 			else if (sdev->inquiry_len)
553 				next_inquiry_len = sdev->inquiry_len;
554 			else
555 				next_inquiry_len = response_len;
556 
557 			/* If more data is available perform the second pass */
558 			if (next_inquiry_len > try_inquiry_len) {
559 				try_inquiry_len = next_inquiry_len;
560 				pass = 2;
561 				goto next_pass;
562 			}
563 		}
564 
565 	} else if (pass == 2) {
566 		printk(KERN_INFO "scsi scan: %d byte inquiry failed.  "
567 				"Consider BLIST_INQUIRY_36 for this device\n",
568 				try_inquiry_len);
569 
570 		/* If this pass failed, the third pass goes back and transfers
571 		 * the same amount as we successfully got in the first pass. */
572 		try_inquiry_len = first_inquiry_len;
573 		pass = 3;
574 		goto next_pass;
575 	}
576 
577 	/* If the last transfer attempt got an error, assume the
578 	 * peripheral doesn't exist or is dead. */
579 	if (result)
580 		return -EIO;
581 
582 	/* Don't report any more data than the device says is valid */
583 	sdev->inquiry_len = min(try_inquiry_len, response_len);
584 
585 	/*
586 	 * XXX Abort if the response length is less than 36? If less than
587 	 * 32, the lookup of the device flags (above) could be invalid,
588 	 * and it would be possible to take an incorrect action - we do
589 	 * not want to hang because of a short INQUIRY. On the flip side,
590 	 * if the device is spun down or becoming ready (and so it gives a
591 	 * short INQUIRY), an abort here prevents any further use of the
592 	 * device, including spin up.
593 	 *
594 	 * Related to the above issue:
595 	 *
596 	 * XXX Devices (disk or all?) should be sent a TEST UNIT READY,
597 	 * and if not ready, sent a START_STOP to start (maybe spin up) and
598 	 * then send the INQUIRY again, since the INQUIRY can change after
599 	 * a device is initialized.
600 	 *
601 	 * Ideally, start a device if explicitly asked to do so.  This
602 	 * assumes that a device is spun up on power on, spun down on
603 	 * request, and then spun up on request.
604 	 */
605 
606 	/*
607 	 * The scanning code needs to know the scsi_level, even if no
608 	 * device is attached at LUN 0 (SCSI_SCAN_TARGET_PRESENT) so
609 	 * non-zero LUNs can be scanned.
610 	 */
611 	sdev->scsi_level = inq_result[2] & 0x07;
612 	if (sdev->scsi_level >= 2 ||
613 	    (sdev->scsi_level == 1 && (inq_result[3] & 0x0f) == 1))
614 		sdev->scsi_level++;
615 	sdev->sdev_target->scsi_level = sdev->scsi_level;
616 
617 	return 0;
618 }
619 
620 /**
621  * scsi_add_lun - allocate and fully initialze a scsi_device
622  * @sdevscan:	holds information to be stored in the new scsi_device
623  * @sdevnew:	store the address of the newly allocated scsi_device
624  * @inq_result:	holds the result of a previous INQUIRY to the LUN
625  * @bflags:	black/white list flag
626  *
627  * Description:
628  *     Allocate and initialize a scsi_device matching sdevscan. Optionally
629  *     set fields based on values in *@bflags. If @sdevnew is not
630  *     NULL, store the address of the new scsi_device in *@sdevnew (needed
631  *     when scanning a particular LUN).
632  *
633  * Return:
634  *     SCSI_SCAN_NO_RESPONSE: could not allocate or setup a scsi_device
635  *     SCSI_SCAN_LUN_PRESENT: a new scsi_device was allocated and initialized
636  **/
637 static int scsi_add_lun(struct scsi_device *sdev, char *inq_result, int *bflags)
638 {
639 	/*
640 	 * XXX do not save the inquiry, since it can change underneath us,
641 	 * save just vendor/model/rev.
642 	 *
643 	 * Rather than save it and have an ioctl that retrieves the saved
644 	 * value, have an ioctl that executes the same INQUIRY code used
645 	 * in scsi_probe_lun, let user level programs doing INQUIRY
646 	 * scanning run at their own risk, or supply a user level program
647 	 * that can correctly scan.
648 	 */
649 	sdev->inquiry = kmalloc(sdev->inquiry_len, GFP_ATOMIC);
650 	if (sdev->inquiry == NULL) {
651 		return SCSI_SCAN_NO_RESPONSE;
652 	}
653 
654 	memcpy(sdev->inquiry, inq_result, sdev->inquiry_len);
655 	sdev->vendor = (char *) (sdev->inquiry + 8);
656 	sdev->model = (char *) (sdev->inquiry + 16);
657 	sdev->rev = (char *) (sdev->inquiry + 32);
658 
659 	if (*bflags & BLIST_ISROM) {
660 		/*
661 		 * It would be better to modify sdev->type, and set
662 		 * sdev->removable, but then the print_inquiry() output
663 		 * would not show TYPE_ROM; if print_inquiry() is removed
664 		 * the issue goes away.
665 		 */
666 		inq_result[0] = TYPE_ROM;
667 		inq_result[1] |= 0x80;	/* removable */
668 	} else if (*bflags & BLIST_NO_ULD_ATTACH)
669 		sdev->no_uld_attach = 1;
670 
671 	switch (sdev->type = (inq_result[0] & 0x1f)) {
672 	case TYPE_TAPE:
673 	case TYPE_DISK:
674 	case TYPE_PRINTER:
675 	case TYPE_MOD:
676 	case TYPE_PROCESSOR:
677 	case TYPE_SCANNER:
678 	case TYPE_MEDIUM_CHANGER:
679 	case TYPE_ENCLOSURE:
680 	case TYPE_COMM:
681 	case TYPE_RBC:
682 		sdev->writeable = 1;
683 		break;
684 	case TYPE_WORM:
685 	case TYPE_ROM:
686 		sdev->writeable = 0;
687 		break;
688 	default:
689 		printk(KERN_INFO "scsi: unknown device type %d\n", sdev->type);
690 	}
691 
692 	print_inquiry(inq_result);
693 
694 	/*
695 	 * For a peripheral qualifier (PQ) value of 1 (001b), the SCSI
696 	 * spec says: The device server is capable of supporting the
697 	 * specified peripheral device type on this logical unit. However,
698 	 * the physical device is not currently connected to this logical
699 	 * unit.
700 	 *
701 	 * The above is vague, as it implies that we could treat 001 and
702 	 * 011 the same. Stay compatible with previous code, and create a
703 	 * scsi_device for a PQ of 1
704 	 *
705 	 * Don't set the device offline here; rather let the upper
706 	 * level drivers eval the PQ to decide whether they should
707 	 * attach. So remove ((inq_result[0] >> 5) & 7) == 1 check.
708 	 */
709 
710 	sdev->inq_periph_qual = (inq_result[0] >> 5) & 7;
711 	sdev->removable = (0x80 & inq_result[1]) >> 7;
712 	sdev->lockable = sdev->removable;
713 	sdev->soft_reset = (inq_result[7] & 1) && ((inq_result[3] & 7) == 2);
714 
715 	if (sdev->scsi_level >= SCSI_3 || (sdev->inquiry_len > 56 &&
716 		inq_result[56] & 0x04))
717 		sdev->ppr = 1;
718 	if (inq_result[7] & 0x60)
719 		sdev->wdtr = 1;
720 	if (inq_result[7] & 0x10)
721 		sdev->sdtr = 1;
722 
723 	sprintf(sdev->devfs_name, "scsi/host%d/bus%d/target%d/lun%d",
724 				sdev->host->host_no, sdev->channel,
725 				sdev->id, sdev->lun);
726 
727 	/*
728 	 * End driverfs/devfs code.
729 	 */
730 
731 	if ((sdev->scsi_level >= SCSI_2) && (inq_result[7] & 2) &&
732 	    !(*bflags & BLIST_NOTQ))
733 		sdev->tagged_supported = 1;
734 	/*
735 	 * Some devices (Texel CD ROM drives) have handshaking problems
736 	 * when used with the Seagate controllers. borken is initialized
737 	 * to 1, and then set it to 0 here.
738 	 */
739 	if ((*bflags & BLIST_BORKEN) == 0)
740 		sdev->borken = 0;
741 
742 	/*
743 	 * Apparently some really broken devices (contrary to the SCSI
744 	 * standards) need to be selected without asserting ATN
745 	 */
746 	if (*bflags & BLIST_SELECT_NO_ATN)
747 		sdev->select_no_atn = 1;
748 
749 	/*
750 	 * Some devices may not want to have a start command automatically
751 	 * issued when a device is added.
752 	 */
753 	if (*bflags & BLIST_NOSTARTONADD)
754 		sdev->no_start_on_add = 1;
755 
756 	if (*bflags & BLIST_SINGLELUN)
757 		sdev->single_lun = 1;
758 
759 
760 	sdev->use_10_for_rw = 1;
761 
762 	if (*bflags & BLIST_MS_SKIP_PAGE_08)
763 		sdev->skip_ms_page_8 = 1;
764 
765 	if (*bflags & BLIST_MS_SKIP_PAGE_3F)
766 		sdev->skip_ms_page_3f = 1;
767 
768 	if (*bflags & BLIST_USE_10_BYTE_MS)
769 		sdev->use_10_for_ms = 1;
770 
771 	/* set the device running here so that slave configure
772 	 * may do I/O */
773 	scsi_device_set_state(sdev, SDEV_RUNNING);
774 
775 	if (*bflags & BLIST_MS_192_BYTES_FOR_3F)
776 		sdev->use_192_bytes_for_3f = 1;
777 
778 	if (*bflags & BLIST_NOT_LOCKABLE)
779 		sdev->lockable = 0;
780 
781 	if (*bflags & BLIST_RETRY_HWERROR)
782 		sdev->retry_hwerror = 1;
783 
784 	transport_configure_device(&sdev->sdev_gendev);
785 
786 	if (sdev->host->hostt->slave_configure)
787 		sdev->host->hostt->slave_configure(sdev);
788 
789 	/*
790 	 * Ok, the device is now all set up, we can
791 	 * register it and tell the rest of the kernel
792 	 * about it.
793 	 */
794 	if (scsi_sysfs_add_sdev(sdev) != 0)
795 		return SCSI_SCAN_NO_RESPONSE;
796 
797 	return SCSI_SCAN_LUN_PRESENT;
798 }
799 
800 static inline void scsi_destroy_sdev(struct scsi_device *sdev)
801 {
802 	if (sdev->host->hostt->slave_destroy)
803 		sdev->host->hostt->slave_destroy(sdev);
804 	transport_destroy_device(&sdev->sdev_gendev);
805 	put_device(&sdev->sdev_gendev);
806 }
807 
808 
809 /**
810  * scsi_probe_and_add_lun - probe a LUN, if a LUN is found add it
811  * @starget:	pointer to target device structure
812  * @lun:	LUN of target device
813  * @sdevscan:	probe the LUN corresponding to this scsi_device
814  * @sdevnew:	store the value of any new scsi_device allocated
815  * @bflagsp:	store bflags here if not NULL
816  *
817  * Description:
818  *     Call scsi_probe_lun, if a LUN with an attached device is found,
819  *     allocate and set it up by calling scsi_add_lun.
820  *
821  * Return:
822  *     SCSI_SCAN_NO_RESPONSE: could not allocate or setup a scsi_device
823  *     SCSI_SCAN_TARGET_PRESENT: target responded, but no device is
824  *         attached at the LUN
825  *     SCSI_SCAN_LUN_PRESENT: a new scsi_device was allocated and initialized
826  **/
827 static int scsi_probe_and_add_lun(struct scsi_target *starget,
828 				  uint lun, int *bflagsp,
829 				  struct scsi_device **sdevp, int rescan,
830 				  void *hostdata)
831 {
832 	struct scsi_device *sdev;
833 	unsigned char *result;
834 	int bflags, res = SCSI_SCAN_NO_RESPONSE, result_len = 256;
835 	struct Scsi_Host *shost = dev_to_shost(starget->dev.parent);
836 
837 	/*
838 	 * The rescan flag is used as an optimization, the first scan of a
839 	 * host adapter calls into here with rescan == 0.
840 	 */
841 	sdev = scsi_device_lookup_by_target(starget, lun);
842 	if (sdev) {
843 		if (rescan || sdev->sdev_state != SDEV_CREATED) {
844 			SCSI_LOG_SCAN_BUS(3, printk(KERN_INFO
845 				"scsi scan: device exists on %s\n",
846 				sdev->sdev_gendev.bus_id));
847 			if (sdevp)
848 				*sdevp = sdev;
849 			else
850 				scsi_device_put(sdev);
851 
852 			if (bflagsp)
853 				*bflagsp = scsi_get_device_flags(sdev,
854 								 sdev->vendor,
855 								 sdev->model);
856 			return SCSI_SCAN_LUN_PRESENT;
857 		}
858 		scsi_device_put(sdev);
859 	} else
860 		sdev = scsi_alloc_sdev(starget, lun, hostdata);
861 	if (!sdev)
862 		goto out;
863 
864 	result = kmalloc(result_len, GFP_ATOMIC |
865 			((shost->unchecked_isa_dma) ? __GFP_DMA : 0));
866 	if (!result)
867 		goto out_free_sdev;
868 
869 	if (scsi_probe_lun(sdev, result, result_len, &bflags))
870 		goto out_free_result;
871 
872 	/*
873 	 * result contains valid SCSI INQUIRY data.
874 	 */
875 	if ((result[0] >> 5) == 3) {
876 		/*
877 		 * For a Peripheral qualifier 3 (011b), the SCSI
878 		 * spec says: The device server is not capable of
879 		 * supporting a physical device on this logical
880 		 * unit.
881 		 *
882 		 * For disks, this implies that there is no
883 		 * logical disk configured at sdev->lun, but there
884 		 * is a target id responding.
885 		 */
886 		SCSI_LOG_SCAN_BUS(3, printk(KERN_INFO
887 					"scsi scan: peripheral qualifier of 3,"
888 					" no device added\n"));
889 		res = SCSI_SCAN_TARGET_PRESENT;
890 		goto out_free_result;
891 	}
892 
893 	res = scsi_add_lun(sdev, result, &bflags);
894 	if (res == SCSI_SCAN_LUN_PRESENT) {
895 		if (bflags & BLIST_KEY) {
896 			sdev->lockable = 0;
897 			scsi_unlock_floptical(sdev, result);
898 		}
899 		if (bflagsp)
900 			*bflagsp = bflags;
901 	}
902 
903  out_free_result:
904 	kfree(result);
905  out_free_sdev:
906 	if (res == SCSI_SCAN_LUN_PRESENT) {
907 		if (sdevp) {
908 			if (scsi_device_get(sdev) == 0) {
909 				*sdevp = sdev;
910 			} else {
911 				__scsi_remove_device(sdev);
912 				res = SCSI_SCAN_NO_RESPONSE;
913 			}
914 		}
915 	} else
916 		scsi_destroy_sdev(sdev);
917  out:
918 	return res;
919 }
920 
921 /**
922  * scsi_sequential_lun_scan - sequentially scan a SCSI target
923  * @starget:	pointer to target structure to scan
924  * @bflags:	black/white list flag for LUN 0
925  * @lun0_res:	result of scanning LUN 0
926  *
927  * Description:
928  *     Generally, scan from LUN 1 (LUN 0 is assumed to already have been
929  *     scanned) to some maximum lun until a LUN is found with no device
930  *     attached. Use the bflags to figure out any oddities.
931  *
932  *     Modifies sdevscan->lun.
933  **/
934 static void scsi_sequential_lun_scan(struct scsi_target *starget,
935 				     int bflags, int lun0_res, int scsi_level,
936 				     int rescan)
937 {
938 	unsigned int sparse_lun, lun, max_dev_lun;
939 	struct Scsi_Host *shost = dev_to_shost(starget->dev.parent);
940 
941 	SCSI_LOG_SCAN_BUS(3, printk(KERN_INFO "scsi scan: Sequential scan of"
942 				    "%s\n", starget->dev.bus_id));
943 
944 	max_dev_lun = min(max_scsi_luns, shost->max_lun);
945 	/*
946 	 * If this device is known to support sparse multiple units,
947 	 * override the other settings, and scan all of them. Normally,
948 	 * SCSI-3 devices should be scanned via the REPORT LUNS.
949 	 */
950 	if (bflags & BLIST_SPARSELUN) {
951 		max_dev_lun = shost->max_lun;
952 		sparse_lun = 1;
953 	} else
954 		sparse_lun = 0;
955 
956 	/*
957 	 * If not sparse lun and no device attached at LUN 0 do not scan
958 	 * any further.
959 	 */
960 	if (!sparse_lun && (lun0_res != SCSI_SCAN_LUN_PRESENT))
961 		return;
962 
963 	/*
964 	 * If less than SCSI_1_CSS, and no special lun scaning, stop
965 	 * scanning; this matches 2.4 behaviour, but could just be a bug
966 	 * (to continue scanning a SCSI_1_CSS device).
967 	 *
968 	 * This test is broken.  We might not have any device on lun0 for
969 	 * a sparselun device, and if that's the case then how would we
970 	 * know the real scsi_level, eh?  It might make sense to just not
971 	 * scan any SCSI_1 device for non-0 luns, but that check would best
972 	 * go into scsi_alloc_sdev() and just have it return null when asked
973 	 * to alloc an sdev for lun > 0 on an already found SCSI_1 device.
974 	 *
975 	if ((sdevscan->scsi_level < SCSI_1_CCS) &&
976 	    ((bflags & (BLIST_FORCELUN | BLIST_SPARSELUN | BLIST_MAX5LUN))
977 	     == 0))
978 		return;
979 	 */
980 	/*
981 	 * If this device is known to support multiple units, override
982 	 * the other settings, and scan all of them.
983 	 */
984 	if (bflags & BLIST_FORCELUN)
985 		max_dev_lun = shost->max_lun;
986 	/*
987 	 * REGAL CDC-4X: avoid hang after LUN 4
988 	 */
989 	if (bflags & BLIST_MAX5LUN)
990 		max_dev_lun = min(5U, max_dev_lun);
991 	/*
992 	 * Do not scan SCSI-2 or lower device past LUN 7, unless
993 	 * BLIST_LARGELUN.
994 	 */
995 	if (scsi_level < SCSI_3 && !(bflags & BLIST_LARGELUN))
996 		max_dev_lun = min(8U, max_dev_lun);
997 
998 	/*
999 	 * We have already scanned LUN 0, so start at LUN 1. Keep scanning
1000 	 * until we reach the max, or no LUN is found and we are not
1001 	 * sparse_lun.
1002 	 */
1003 	for (lun = 1; lun < max_dev_lun; ++lun)
1004 		if ((scsi_probe_and_add_lun(starget, lun, NULL, NULL, rescan,
1005 					    NULL) != SCSI_SCAN_LUN_PRESENT) &&
1006 		    !sparse_lun)
1007 			return;
1008 }
1009 
1010 /**
1011  * scsilun_to_int: convert a scsi_lun to an int
1012  * @scsilun:	struct scsi_lun to be converted.
1013  *
1014  * Description:
1015  *     Convert @scsilun from a struct scsi_lun to a four byte host byte-ordered
1016  *     integer, and return the result. The caller must check for
1017  *     truncation before using this function.
1018  *
1019  * Notes:
1020  *     The struct scsi_lun is assumed to be four levels, with each level
1021  *     effectively containing a SCSI byte-ordered (big endian) short; the
1022  *     addressing bits of each level are ignored (the highest two bits).
1023  *     For a description of the LUN format, post SCSI-3 see the SCSI
1024  *     Architecture Model, for SCSI-3 see the SCSI Controller Commands.
1025  *
1026  *     Given a struct scsi_lun of: 0a 04 0b 03 00 00 00 00, this function returns
1027  *     the integer: 0x0b030a04
1028  **/
1029 static int scsilun_to_int(struct scsi_lun *scsilun)
1030 {
1031 	int i;
1032 	unsigned int lun;
1033 
1034 	lun = 0;
1035 	for (i = 0; i < sizeof(lun); i += 2)
1036 		lun = lun | (((scsilun->scsi_lun[i] << 8) |
1037 			      scsilun->scsi_lun[i + 1]) << (i * 8));
1038 	return lun;
1039 }
1040 
1041 /**
1042  * int_to_scsilun: reverts an int into a scsi_lun
1043  * @int:        integer to be reverted
1044  * @scsilun:	struct scsi_lun to be set.
1045  *
1046  * Description:
1047  *     Reverts the functionality of the scsilun_to_int, which packed
1048  *     an 8-byte lun value into an int. This routine unpacks the int
1049  *     back into the lun value.
1050  *     Note: the scsilun_to_int() routine does not truly handle all
1051  *     8bytes of the lun value. This functions restores only as much
1052  *     as was set by the routine.
1053  *
1054  * Notes:
1055  *     Given an integer : 0x0b030a04,  this function returns a
1056  *     scsi_lun of : struct scsi_lun of: 0a 04 0b 03 00 00 00 00
1057  *
1058  **/
1059 void int_to_scsilun(unsigned int lun, struct scsi_lun *scsilun)
1060 {
1061 	int i;
1062 
1063 	memset(scsilun->scsi_lun, 0, sizeof(scsilun->scsi_lun));
1064 
1065 	for (i = 0; i < sizeof(lun); i += 2) {
1066 		scsilun->scsi_lun[i] = (lun >> 8) & 0xFF;
1067 		scsilun->scsi_lun[i+1] = lun & 0xFF;
1068 		lun = lun >> 16;
1069 	}
1070 }
1071 EXPORT_SYMBOL(int_to_scsilun);
1072 
1073 /**
1074  * scsi_report_lun_scan - Scan using SCSI REPORT LUN results
1075  * @sdevscan:	scan the host, channel, and id of this scsi_device
1076  *
1077  * Description:
1078  *     If @sdevscan is for a SCSI-3 or up device, send a REPORT LUN
1079  *     command, and scan the resulting list of LUNs by calling
1080  *     scsi_probe_and_add_lun.
1081  *
1082  *     Modifies sdevscan->lun.
1083  *
1084  * Return:
1085  *     0: scan completed (or no memory, so further scanning is futile)
1086  *     1: no report lun scan, or not configured
1087  **/
1088 static int scsi_report_lun_scan(struct scsi_target *starget, int bflags,
1089 				int rescan)
1090 {
1091 	char devname[64];
1092 	unsigned char scsi_cmd[MAX_COMMAND_SIZE];
1093 	unsigned int length;
1094 	unsigned int lun;
1095 	unsigned int num_luns;
1096 	unsigned int retries;
1097 	int result;
1098 	struct scsi_lun *lunp, *lun_data;
1099 	u8 *data;
1100 	struct scsi_sense_hdr sshdr;
1101 	struct scsi_device *sdev;
1102 	struct Scsi_Host *shost = dev_to_shost(&starget->dev);
1103 	int ret = 0;
1104 
1105 	/*
1106 	 * Only support SCSI-3 and up devices if BLIST_NOREPORTLUN is not set.
1107 	 * Also allow SCSI-2 if BLIST_REPORTLUN2 is set and host adapter does
1108 	 * support more than 8 LUNs.
1109 	 */
1110 	if ((bflags & BLIST_NOREPORTLUN) ||
1111 	     starget->scsi_level < SCSI_2 ||
1112 	    (starget->scsi_level < SCSI_3 &&
1113 	     (!(bflags & BLIST_REPORTLUN2) || shost->max_lun <= 8)) )
1114 		return 1;
1115 	if (bflags & BLIST_NOLUN)
1116 		return 0;
1117 
1118 	if (!(sdev = scsi_device_lookup_by_target(starget, 0))) {
1119 		sdev = scsi_alloc_sdev(starget, 0, NULL);
1120 		if (!sdev)
1121 			return 0;
1122 		if (scsi_device_get(sdev))
1123 			return 0;
1124 	}
1125 
1126 	sprintf(devname, "host %d channel %d id %d",
1127 		shost->host_no, sdev->channel, sdev->id);
1128 
1129 	/*
1130 	 * Allocate enough to hold the header (the same size as one scsi_lun)
1131 	 * plus the max number of luns we are requesting.
1132 	 *
1133 	 * Reallocating and trying again (with the exact amount we need)
1134 	 * would be nice, but then we need to somehow limit the size
1135 	 * allocated based on the available memory and the limits of
1136 	 * kmalloc - we don't want a kmalloc() failure of a huge value to
1137 	 * prevent us from finding any LUNs on this target.
1138 	 */
1139 	length = (max_scsi_report_luns + 1) * sizeof(struct scsi_lun);
1140 	lun_data = kmalloc(length, GFP_ATOMIC |
1141 			   (sdev->host->unchecked_isa_dma ? __GFP_DMA : 0));
1142 	if (!lun_data) {
1143 		printk(ALLOC_FAILURE_MSG, __FUNCTION__);
1144 		goto out;
1145 	}
1146 
1147 	scsi_cmd[0] = REPORT_LUNS;
1148 
1149 	/*
1150 	 * bytes 1 - 5: reserved, set to zero.
1151 	 */
1152 	memset(&scsi_cmd[1], 0, 5);
1153 
1154 	/*
1155 	 * bytes 6 - 9: length of the command.
1156 	 */
1157 	scsi_cmd[6] = (unsigned char) (length >> 24) & 0xff;
1158 	scsi_cmd[7] = (unsigned char) (length >> 16) & 0xff;
1159 	scsi_cmd[8] = (unsigned char) (length >> 8) & 0xff;
1160 	scsi_cmd[9] = (unsigned char) length & 0xff;
1161 
1162 	scsi_cmd[10] = 0;	/* reserved */
1163 	scsi_cmd[11] = 0;	/* control */
1164 
1165 	/*
1166 	 * We can get a UNIT ATTENTION, for example a power on/reset, so
1167 	 * retry a few times (like sd.c does for TEST UNIT READY).
1168 	 * Experience shows some combinations of adapter/devices get at
1169 	 * least two power on/resets.
1170 	 *
1171 	 * Illegal requests (for devices that do not support REPORT LUNS)
1172 	 * should come through as a check condition, and will not generate
1173 	 * a retry.
1174 	 */
1175 	for (retries = 0; retries < 3; retries++) {
1176 		SCSI_LOG_SCAN_BUS(3, printk (KERN_INFO "scsi scan: Sending"
1177 				" REPORT LUNS to %s (try %d)\n", devname,
1178 				retries));
1179 
1180 		result = scsi_execute_req(sdev, scsi_cmd, DMA_FROM_DEVICE,
1181 					  lun_data, length, &sshdr,
1182 					  SCSI_TIMEOUT + 4 * HZ, 3);
1183 
1184 		SCSI_LOG_SCAN_BUS(3, printk (KERN_INFO "scsi scan: REPORT LUNS"
1185 				" %s (try %d) result 0x%x\n", result
1186 				?  "failed" : "successful", retries, result));
1187 		if (result == 0)
1188 			break;
1189 		else if (scsi_sense_valid(&sshdr)) {
1190 			if (sshdr.sense_key != UNIT_ATTENTION)
1191 				break;
1192 		}
1193 	}
1194 
1195 	if (result) {
1196 		/*
1197 		 * The device probably does not support a REPORT LUN command
1198 		 */
1199 		ret = 1;
1200 		goto out_err;
1201 	}
1202 
1203 	/*
1204 	 * Get the length from the first four bytes of lun_data.
1205 	 */
1206 	data = (u8 *) lun_data->scsi_lun;
1207 	length = ((data[0] << 24) | (data[1] << 16) |
1208 		  (data[2] << 8) | (data[3] << 0));
1209 
1210 	num_luns = (length / sizeof(struct scsi_lun));
1211 	if (num_luns > max_scsi_report_luns) {
1212 		printk(KERN_WARNING "scsi: On %s only %d (max_scsi_report_luns)"
1213 		       " of %d luns reported, try increasing"
1214 		       " max_scsi_report_luns.\n", devname,
1215 		       max_scsi_report_luns, num_luns);
1216 		num_luns = max_scsi_report_luns;
1217 	}
1218 
1219 	SCSI_LOG_SCAN_BUS(3, sdev_printk (KERN_INFO, sdev,
1220 		"scsi scan: REPORT LUN scan\n"));
1221 
1222 	/*
1223 	 * Scan the luns in lun_data. The entry at offset 0 is really
1224 	 * the header, so start at 1 and go up to and including num_luns.
1225 	 */
1226 	for (lunp = &lun_data[1]; lunp <= &lun_data[num_luns]; lunp++) {
1227 		lun = scsilun_to_int(lunp);
1228 
1229 		/*
1230 		 * Check if the unused part of lunp is non-zero, and so
1231 		 * does not fit in lun.
1232 		 */
1233 		if (memcmp(&lunp->scsi_lun[sizeof(lun)], "\0\0\0\0", 4)) {
1234 			int i;
1235 
1236 			/*
1237 			 * Output an error displaying the LUN in byte order,
1238 			 * this differs from what linux would print for the
1239 			 * integer LUN value.
1240 			 */
1241 			printk(KERN_WARNING "scsi: %s lun 0x", devname);
1242 			data = (char *)lunp->scsi_lun;
1243 			for (i = 0; i < sizeof(struct scsi_lun); i++)
1244 				printk("%02x", data[i]);
1245 			printk(" has a LUN larger than currently supported.\n");
1246 		} else if (lun > sdev->host->max_lun) {
1247 			printk(KERN_WARNING "scsi: %s lun%d has a LUN larger"
1248 			       " than allowed by the host adapter\n",
1249 			       devname, lun);
1250 		} else {
1251 			int res;
1252 
1253 			res = scsi_probe_and_add_lun(starget,
1254 				lun, NULL, NULL, rescan, NULL);
1255 			if (res == SCSI_SCAN_NO_RESPONSE) {
1256 				/*
1257 				 * Got some results, but now none, abort.
1258 				 */
1259 				sdev_printk(KERN_ERR, sdev,
1260 					"Unexpected response"
1261 				        " from lun %d while scanning, scan"
1262 				        " aborted\n", lun);
1263 				break;
1264 			}
1265 		}
1266 	}
1267 
1268  out_err:
1269 	kfree(lun_data);
1270  out:
1271 	scsi_device_put(sdev);
1272 	if (sdev->sdev_state == SDEV_CREATED)
1273 		/*
1274 		 * the sdev we used didn't appear in the report luns scan
1275 		 */
1276 		scsi_destroy_sdev(sdev);
1277 	return ret;
1278 }
1279 
1280 struct scsi_device *__scsi_add_device(struct Scsi_Host *shost, uint channel,
1281 				      uint id, uint lun, void *hostdata)
1282 {
1283 	struct scsi_device *sdev;
1284 	struct device *parent = &shost->shost_gendev;
1285 	int res;
1286 	struct scsi_target *starget = scsi_alloc_target(parent, channel, id);
1287 
1288 	if (!starget)
1289 		return ERR_PTR(-ENOMEM);
1290 
1291 	get_device(&starget->dev);
1292 	down(&shost->scan_mutex);
1293 	if (scsi_host_scan_allowed(shost)) {
1294 		res = scsi_probe_and_add_lun(starget, lun, NULL, &sdev, 1,
1295 					     hostdata);
1296 		if (res != SCSI_SCAN_LUN_PRESENT)
1297 			sdev = ERR_PTR(-ENODEV);
1298 	}
1299 	up(&shost->scan_mutex);
1300 	scsi_target_reap(starget);
1301 	put_device(&starget->dev);
1302 
1303 	return sdev;
1304 }
1305 EXPORT_SYMBOL(__scsi_add_device);
1306 
1307 int scsi_add_device(struct Scsi_Host *host, uint channel,
1308 		    uint target, uint lun)
1309 {
1310 	struct scsi_device *sdev =
1311 		__scsi_add_device(host, channel, target, lun, NULL);
1312 	if (IS_ERR(sdev))
1313 		return PTR_ERR(sdev);
1314 
1315 	scsi_device_put(sdev);
1316 	return 0;
1317 }
1318 EXPORT_SYMBOL(scsi_add_device);
1319 
1320 void scsi_rescan_device(struct device *dev)
1321 {
1322 	struct scsi_driver *drv;
1323 
1324 	if (!dev->driver)
1325 		return;
1326 
1327 	drv = to_scsi_driver(dev->driver);
1328 	if (try_module_get(drv->owner)) {
1329 		if (drv->rescan)
1330 			drv->rescan(dev);
1331 		module_put(drv->owner);
1332 	}
1333 }
1334 EXPORT_SYMBOL(scsi_rescan_device);
1335 
1336 static void __scsi_scan_target(struct device *parent, unsigned int channel,
1337 		unsigned int id, unsigned int lun, int rescan)
1338 {
1339 	struct Scsi_Host *shost = dev_to_shost(parent);
1340 	int bflags = 0;
1341 	int res;
1342 	struct scsi_target *starget;
1343 
1344 	if (shost->this_id == id)
1345 		/*
1346 		 * Don't scan the host adapter
1347 		 */
1348 		return;
1349 
1350 	starget = scsi_alloc_target(parent, channel, id);
1351 	if (!starget)
1352 		return;
1353 
1354 	get_device(&starget->dev);
1355 	if (lun != SCAN_WILD_CARD) {
1356 		/*
1357 		 * Scan for a specific host/chan/id/lun.
1358 		 */
1359 		scsi_probe_and_add_lun(starget, lun, NULL, NULL, rescan, NULL);
1360 		goto out_reap;
1361 	}
1362 
1363 	/*
1364 	 * Scan LUN 0, if there is some response, scan further. Ideally, we
1365 	 * would not configure LUN 0 until all LUNs are scanned.
1366 	 */
1367 	res = scsi_probe_and_add_lun(starget, 0, &bflags, NULL, rescan, NULL);
1368 	if (res == SCSI_SCAN_LUN_PRESENT || res == SCSI_SCAN_TARGET_PRESENT) {
1369 		if (scsi_report_lun_scan(starget, bflags, rescan) != 0)
1370 			/*
1371 			 * The REPORT LUN did not scan the target,
1372 			 * do a sequential scan.
1373 			 */
1374 			scsi_sequential_lun_scan(starget, bflags,
1375 				       	res, starget->scsi_level, rescan);
1376 	}
1377 
1378  out_reap:
1379 	/* now determine if the target has any children at all
1380 	 * and if not, nuke it */
1381 	scsi_target_reap(starget);
1382 
1383 	put_device(&starget->dev);
1384 }
1385 
1386 /**
1387  * scsi_scan_target - scan a target id, possibly including all LUNs on the
1388  *     target.
1389  * @parent:	host to scan
1390  * @channel:	channel to scan
1391  * @id:		target id to scan
1392  * @lun:	Specific LUN to scan or SCAN_WILD_CARD
1393  * @rescan:	passed to LUN scanning routines
1394  *
1395  * Description:
1396  *     Scan the target id on @parent, @channel, and @id. Scan at least LUN 0,
1397  *     and possibly all LUNs on the target id.
1398  *
1399  *     First try a REPORT LUN scan, if that does not scan the target, do a
1400  *     sequential scan of LUNs on the target id.
1401  **/
1402 void scsi_scan_target(struct device *parent, unsigned int channel,
1403 		      unsigned int id, unsigned int lun, int rescan)
1404 {
1405 	struct Scsi_Host *shost = dev_to_shost(parent);
1406 
1407 	down(&shost->scan_mutex);
1408 	if (scsi_host_scan_allowed(shost))
1409 		__scsi_scan_target(parent, channel, id, lun, rescan);
1410 	up(&shost->scan_mutex);
1411 }
1412 EXPORT_SYMBOL(scsi_scan_target);
1413 
1414 static void scsi_scan_channel(struct Scsi_Host *shost, unsigned int channel,
1415 			      unsigned int id, unsigned int lun, int rescan)
1416 {
1417 	uint order_id;
1418 
1419 	if (id == SCAN_WILD_CARD)
1420 		for (id = 0; id < shost->max_id; ++id) {
1421 			/*
1422 			 * XXX adapter drivers when possible (FCP, iSCSI)
1423 			 * could modify max_id to match the current max,
1424 			 * not the absolute max.
1425 			 *
1426 			 * XXX add a shost id iterator, so for example,
1427 			 * the FC ID can be the same as a target id
1428 			 * without a huge overhead of sparse id's.
1429 			 */
1430 			if (shost->reverse_ordering)
1431 				/*
1432 				 * Scan from high to low id.
1433 				 */
1434 				order_id = shost->max_id - id - 1;
1435 			else
1436 				order_id = id;
1437 			__scsi_scan_target(&shost->shost_gendev, channel,
1438 					order_id, lun, rescan);
1439 		}
1440 	else
1441 		__scsi_scan_target(&shost->shost_gendev, channel,
1442 				id, lun, rescan);
1443 }
1444 
1445 int scsi_scan_host_selected(struct Scsi_Host *shost, unsigned int channel,
1446 			    unsigned int id, unsigned int lun, int rescan)
1447 {
1448 	SCSI_LOG_SCAN_BUS(3, shost_printk (KERN_INFO, shost,
1449 		"%s: <%u:%u:%u>\n",
1450 		__FUNCTION__, channel, id, lun));
1451 
1452 	if (((channel != SCAN_WILD_CARD) && (channel > shost->max_channel)) ||
1453 	    ((id != SCAN_WILD_CARD) && (id > shost->max_id)) ||
1454 	    ((lun != SCAN_WILD_CARD) && (lun > shost->max_lun)))
1455 		return -EINVAL;
1456 
1457 	down(&shost->scan_mutex);
1458 	if (scsi_host_scan_allowed(shost)) {
1459 		if (channel == SCAN_WILD_CARD)
1460 			for (channel = 0; channel <= shost->max_channel;
1461 			     channel++)
1462 				scsi_scan_channel(shost, channel, id, lun,
1463 						  rescan);
1464 		else
1465 			scsi_scan_channel(shost, channel, id, lun, rescan);
1466 	}
1467 	up(&shost->scan_mutex);
1468 
1469 	return 0;
1470 }
1471 
1472 /**
1473  * scsi_scan_host - scan the given adapter
1474  * @shost:	adapter to scan
1475  **/
1476 void scsi_scan_host(struct Scsi_Host *shost)
1477 {
1478 	scsi_scan_host_selected(shost, SCAN_WILD_CARD, SCAN_WILD_CARD,
1479 				SCAN_WILD_CARD, 0);
1480 }
1481 EXPORT_SYMBOL(scsi_scan_host);
1482 
1483 void scsi_forget_host(struct Scsi_Host *shost)
1484 {
1485 	struct scsi_device *sdev;
1486 	unsigned long flags;
1487 
1488  restart:
1489 	spin_lock_irqsave(shost->host_lock, flags);
1490 	list_for_each_entry(sdev, &shost->__devices, siblings) {
1491 		if (sdev->sdev_state == SDEV_DEL)
1492 			continue;
1493 		spin_unlock_irqrestore(shost->host_lock, flags);
1494 		__scsi_remove_device(sdev);
1495 		goto restart;
1496 	}
1497 	spin_unlock_irqrestore(shost->host_lock, flags);
1498 }
1499 
1500 /*
1501  * Function:    scsi_get_host_dev()
1502  *
1503  * Purpose:     Create a scsi_device that points to the host adapter itself.
1504  *
1505  * Arguments:   SHpnt   - Host that needs a scsi_device
1506  *
1507  * Lock status: None assumed.
1508  *
1509  * Returns:     The scsi_device or NULL
1510  *
1511  * Notes:
1512  *	Attach a single scsi_device to the Scsi_Host - this should
1513  *	be made to look like a "pseudo-device" that points to the
1514  *	HA itself.
1515  *
1516  *	Note - this device is not accessible from any high-level
1517  *	drivers (including generics), which is probably not
1518  *	optimal.  We can add hooks later to attach
1519  */
1520 struct scsi_device *scsi_get_host_dev(struct Scsi_Host *shost)
1521 {
1522 	struct scsi_device *sdev = NULL;
1523 	struct scsi_target *starget;
1524 
1525 	down(&shost->scan_mutex);
1526 	if (!scsi_host_scan_allowed(shost))
1527 		goto out;
1528 	starget = scsi_alloc_target(&shost->shost_gendev, 0, shost->this_id);
1529 	if (!starget)
1530 		goto out;
1531 
1532 	sdev = scsi_alloc_sdev(starget, 0, NULL);
1533 	if (sdev) {
1534 		sdev->sdev_gendev.parent = get_device(&starget->dev);
1535 		sdev->borken = 0;
1536 	}
1537 	put_device(&starget->dev);
1538  out:
1539 	up(&shost->scan_mutex);
1540 	return sdev;
1541 }
1542 EXPORT_SYMBOL(scsi_get_host_dev);
1543 
1544 /*
1545  * Function:    scsi_free_host_dev()
1546  *
1547  * Purpose:     Free a scsi_device that points to the host adapter itself.
1548  *
1549  * Arguments:   SHpnt   - Host that needs a scsi_device
1550  *
1551  * Lock status: None assumed.
1552  *
1553  * Returns:     Nothing
1554  *
1555  * Notes:
1556  */
1557 void scsi_free_host_dev(struct scsi_device *sdev)
1558 {
1559 	BUG_ON(sdev->id != sdev->host->this_id);
1560 
1561 	scsi_destroy_sdev(sdev);
1562 }
1563 EXPORT_SYMBOL(scsi_free_host_dev);
1564 
1565