xref: /linux/drivers/scsi/scsi_scan.c (revision 2624f124b3b5d550ab2fbef7ee3bc0e1fed09722)
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 
271 			 */
272 			if (ret == -ENXIO)
273 				display_failure_msg = 0;
274 			goto out_device_destroy;
275 		}
276 	}
277 
278 	return sdev;
279 
280 out_device_destroy:
281 	transport_destroy_device(&sdev->sdev_gendev);
282 	scsi_free_queue(sdev->request_queue);
283 	put_device(&sdev->sdev_gendev);
284 out:
285 	if (display_failure_msg)
286 		printk(ALLOC_FAILURE_MSG, __FUNCTION__);
287 	return NULL;
288 }
289 
290 static void scsi_target_dev_release(struct device *dev)
291 {
292 	struct device *parent = dev->parent;
293 	struct scsi_target *starget = to_scsi_target(dev);
294 	struct Scsi_Host *shost = dev_to_shost(parent);
295 
296 	if (shost->hostt->target_destroy)
297 		shost->hostt->target_destroy(starget);
298 	kfree(starget);
299 	put_device(parent);
300 }
301 
302 int scsi_is_target_device(const struct device *dev)
303 {
304 	return dev->release == scsi_target_dev_release;
305 }
306 EXPORT_SYMBOL(scsi_is_target_device);
307 
308 static struct scsi_target *__scsi_find_target(struct device *parent,
309 					      int channel, uint id)
310 {
311 	struct scsi_target *starget, *found_starget = NULL;
312 	struct Scsi_Host *shost = dev_to_shost(parent);
313 	/*
314 	 * Search for an existing target for this sdev.
315 	 */
316 	list_for_each_entry(starget, &shost->__targets, siblings) {
317 		if (starget->id == id &&
318 		    starget->channel == channel) {
319 			found_starget = starget;
320 			break;
321 		}
322 	}
323 	if (found_starget)
324 		get_device(&found_starget->dev);
325 
326 	return found_starget;
327 }
328 
329 static struct scsi_target *scsi_alloc_target(struct device *parent,
330 					     int channel, uint id)
331 {
332 	struct Scsi_Host *shost = dev_to_shost(parent);
333 	struct device *dev = NULL;
334 	unsigned long flags;
335 	const int size = sizeof(struct scsi_target)
336 		+ shost->transportt->target_size;
337 	struct scsi_target *starget;
338 	struct scsi_target *found_target;
339 
340 	/*
341 	 * Obtain the real parent from the transport. The transport
342 	 * is allowed to fail (no error) if there is nothing at that
343 	 * target id.
344 	 */
345 	if (shost->transportt->target_parent) {
346 		spin_lock_irqsave(shost->host_lock, flags);
347 		parent = shost->transportt->target_parent(shost, channel, id);
348 		spin_unlock_irqrestore(shost->host_lock, flags);
349 		if (!parent)
350 			return NULL;
351 	}
352 
353 	starget = kmalloc(size, GFP_KERNEL);
354 	if (!starget) {
355 		printk(KERN_ERR "%s: allocation failure\n", __FUNCTION__);
356 		return NULL;
357 	}
358 	memset(starget, 0, size);
359 	dev = &starget->dev;
360 	device_initialize(dev);
361 	starget->reap_ref = 1;
362 	dev->parent = get_device(parent);
363 	dev->release = scsi_target_dev_release;
364 	sprintf(dev->bus_id, "target%d:%d:%d",
365 		shost->host_no, channel, id);
366 	starget->id = id;
367 	starget->channel = channel;
368 	INIT_LIST_HEAD(&starget->siblings);
369 	INIT_LIST_HEAD(&starget->devices);
370 	spin_lock_irqsave(shost->host_lock, flags);
371 
372 	found_target = __scsi_find_target(parent, channel, id);
373 	if (found_target)
374 		goto found;
375 
376 	list_add_tail(&starget->siblings, &shost->__targets);
377 	spin_unlock_irqrestore(shost->host_lock, flags);
378 	/* allocate and add */
379 	transport_setup_device(dev);
380 	device_add(dev);
381 	transport_add_device(dev);
382 	if (shost->hostt->target_alloc) {
383 		int error = shost->hostt->target_alloc(starget);
384 
385 		if(error) {
386 			dev_printk(KERN_ERR, dev, "target allocation failed, error %d\n", error);
387 			/* don't want scsi_target_reap to do the final
388 			 * put because it will be under the host lock */
389 			get_device(dev);
390 			scsi_target_reap(starget);
391 			put_device(dev);
392 			return NULL;
393 		}
394 	}
395 
396 	return starget;
397 
398  found:
399 	found_target->reap_ref++;
400 	spin_unlock_irqrestore(shost->host_lock, flags);
401 	put_device(parent);
402 	kfree(starget);
403 	return found_target;
404 }
405 
406 /**
407  * scsi_target_reap - check to see if target is in use and destroy if not
408  *
409  * @starget: target to be checked
410  *
411  * This is used after removing a LUN or doing a last put of the target
412  * it checks atomically that nothing is using the target and removes
413  * it if so.
414  */
415 void scsi_target_reap(struct scsi_target *starget)
416 {
417 	struct Scsi_Host *shost = dev_to_shost(starget->dev.parent);
418 	unsigned long flags;
419 	spin_lock_irqsave(shost->host_lock, flags);
420 
421 	if (--starget->reap_ref == 0 && list_empty(&starget->devices)) {
422 		list_del_init(&starget->siblings);
423 		spin_unlock_irqrestore(shost->host_lock, flags);
424 		device_del(&starget->dev);
425 		transport_unregister_device(&starget->dev);
426 		put_device(&starget->dev);
427 		return;
428 	}
429 	spin_unlock_irqrestore(shost->host_lock, flags);
430 }
431 
432 /**
433  * scsi_probe_lun - probe a single LUN using a SCSI INQUIRY
434  * @sdev:	scsi_device to probe
435  * @inq_result:	area to store the INQUIRY result
436  * @result_len: len of inq_result
437  * @bflags:	store any bflags found here
438  *
439  * Description:
440  *     Probe the lun associated with @req using a standard SCSI INQUIRY;
441  *
442  *     If the INQUIRY is successful, zero is returned and the
443  *     INQUIRY data is in @inq_result; the scsi_level and INQUIRY length
444  *     are copied to the Scsi_Device any flags value is stored in *@bflags.
445  **/
446 static int scsi_probe_lun(struct scsi_device *sdev, char *inq_result,
447 			  int result_len, int *bflags)
448 {
449 	unsigned char scsi_cmd[MAX_COMMAND_SIZE];
450 	int first_inquiry_len, try_inquiry_len, next_inquiry_len;
451 	int response_len = 0;
452 	int pass, count, result;
453 	struct scsi_sense_hdr sshdr;
454 
455 	*bflags = 0;
456 
457 	/* Perform up to 3 passes.  The first pass uses a conservative
458 	 * transfer length of 36 unless sdev->inquiry_len specifies a
459 	 * different value. */
460 	first_inquiry_len = sdev->inquiry_len ? sdev->inquiry_len : 36;
461 	try_inquiry_len = first_inquiry_len;
462 	pass = 1;
463 
464  next_pass:
465 	SCSI_LOG_SCAN_BUS(3, printk(KERN_INFO "scsi scan: INQUIRY pass %d "
466 			"to host %d channel %d id %d lun %d, length %d\n",
467 			pass, sdev->host->host_no, sdev->channel,
468 			sdev->id, sdev->lun, try_inquiry_len));
469 
470 	/* Each pass gets up to three chances to ignore Unit Attention */
471 	for (count = 0; count < 3; ++count) {
472 		memset(scsi_cmd, 0, 6);
473 		scsi_cmd[0] = INQUIRY;
474 		scsi_cmd[4] = (unsigned char) try_inquiry_len;
475 
476 		memset(inq_result, 0, try_inquiry_len);
477 
478 		result = scsi_execute_req(sdev,  scsi_cmd, DMA_FROM_DEVICE,
479 					  inq_result, try_inquiry_len, &sshdr,
480 					  HZ / 2 + HZ * scsi_inq_timeout, 3);
481 
482 		SCSI_LOG_SCAN_BUS(3, printk(KERN_INFO "scsi scan: INQUIRY %s "
483 				"with code 0x%x\n",
484 				result ? "failed" : "successful", result));
485 
486 		if (result) {
487 			/*
488 			 * not-ready to ready transition [asc/ascq=0x28/0x0]
489 			 * or power-on, reset [asc/ascq=0x29/0x0], continue.
490 			 * INQUIRY should not yield UNIT_ATTENTION
491 			 * but many buggy devices do so anyway.
492 			 */
493 			if ((driver_byte(result) & DRIVER_SENSE) &&
494 			    scsi_sense_valid(&sshdr)) {
495 				if ((sshdr.sense_key == UNIT_ATTENTION) &&
496 				    ((sshdr.asc == 0x28) ||
497 				     (sshdr.asc == 0x29)) &&
498 				    (sshdr.ascq == 0))
499 					continue;
500 			}
501 		}
502 		break;
503 	}
504 
505 	if (result == 0) {
506 		response_len = (unsigned char) inq_result[4] + 5;
507 		if (response_len > 255)
508 			response_len = first_inquiry_len;	/* sanity */
509 
510 		/*
511 		 * Get any flags for this device.
512 		 *
513 		 * XXX add a bflags to Scsi_Device, and replace the
514 		 * corresponding bit fields in Scsi_Device, so bflags
515 		 * need not be passed as an argument.
516 		 */
517 		*bflags = scsi_get_device_flags(sdev, &inq_result[8],
518 				&inq_result[16]);
519 
520 		/* When the first pass succeeds we gain information about
521 		 * what larger transfer lengths might work. */
522 		if (pass == 1) {
523 			if (BLIST_INQUIRY_36 & *bflags)
524 				next_inquiry_len = 36;
525 			else if (BLIST_INQUIRY_58 & *bflags)
526 				next_inquiry_len = 58;
527 			else if (sdev->inquiry_len)
528 				next_inquiry_len = sdev->inquiry_len;
529 			else
530 				next_inquiry_len = response_len;
531 
532 			/* If more data is available perform the second pass */
533 			if (next_inquiry_len > try_inquiry_len) {
534 				try_inquiry_len = next_inquiry_len;
535 				pass = 2;
536 				goto next_pass;
537 			}
538 		}
539 
540 	} else if (pass == 2) {
541 		printk(KERN_INFO "scsi scan: %d byte inquiry failed.  "
542 				"Consider BLIST_INQUIRY_36 for this device\n",
543 				try_inquiry_len);
544 
545 		/* If this pass failed, the third pass goes back and transfers
546 		 * the same amount as we successfully got in the first pass. */
547 		try_inquiry_len = first_inquiry_len;
548 		pass = 3;
549 		goto next_pass;
550 	}
551 
552 	/* If the last transfer attempt got an error, assume the
553 	 * peripheral doesn't exist or is dead. */
554 	if (result)
555 		return -EIO;
556 
557 	/* Don't report any more data than the device says is valid */
558 	sdev->inquiry_len = min(try_inquiry_len, response_len);
559 
560 	/*
561 	 * XXX Abort if the response length is less than 36? If less than
562 	 * 32, the lookup of the device flags (above) could be invalid,
563 	 * and it would be possible to take an incorrect action - we do
564 	 * not want to hang because of a short INQUIRY. On the flip side,
565 	 * if the device is spun down or becoming ready (and so it gives a
566 	 * short INQUIRY), an abort here prevents any further use of the
567 	 * device, including spin up.
568 	 *
569 	 * Related to the above issue:
570 	 *
571 	 * XXX Devices (disk or all?) should be sent a TEST UNIT READY,
572 	 * and if not ready, sent a START_STOP to start (maybe spin up) and
573 	 * then send the INQUIRY again, since the INQUIRY can change after
574 	 * a device is initialized.
575 	 *
576 	 * Ideally, start a device if explicitly asked to do so.  This
577 	 * assumes that a device is spun up on power on, spun down on
578 	 * request, and then spun up on request.
579 	 */
580 
581 	/*
582 	 * The scanning code needs to know the scsi_level, even if no
583 	 * device is attached at LUN 0 (SCSI_SCAN_TARGET_PRESENT) so
584 	 * non-zero LUNs can be scanned.
585 	 */
586 	sdev->scsi_level = inq_result[2] & 0x07;
587 	if (sdev->scsi_level >= 2 ||
588 	    (sdev->scsi_level == 1 && (inq_result[3] & 0x0f) == 1))
589 		sdev->scsi_level++;
590 
591 	return 0;
592 }
593 
594 /**
595  * scsi_add_lun - allocate and fully initialze a Scsi_Device
596  * @sdevscan:	holds information to be stored in the new Scsi_Device
597  * @sdevnew:	store the address of the newly allocated Scsi_Device
598  * @inq_result:	holds the result of a previous INQUIRY to the LUN
599  * @bflags:	black/white list flag
600  *
601  * Description:
602  *     Allocate and initialize a Scsi_Device matching sdevscan. Optionally
603  *     set fields based on values in *@bflags. If @sdevnew is not
604  *     NULL, store the address of the new Scsi_Device in *@sdevnew (needed
605  *     when scanning a particular LUN).
606  *
607  * Return:
608  *     SCSI_SCAN_NO_RESPONSE: could not allocate or setup a Scsi_Device
609  *     SCSI_SCAN_LUN_PRESENT: a new Scsi_Device was allocated and initialized
610  **/
611 static int scsi_add_lun(struct scsi_device *sdev, char *inq_result, int *bflags)
612 {
613 	/*
614 	 * XXX do not save the inquiry, since it can change underneath us,
615 	 * save just vendor/model/rev.
616 	 *
617 	 * Rather than save it and have an ioctl that retrieves the saved
618 	 * value, have an ioctl that executes the same INQUIRY code used
619 	 * in scsi_probe_lun, let user level programs doing INQUIRY
620 	 * scanning run at their own risk, or supply a user level program
621 	 * that can correctly scan.
622 	 */
623 	sdev->inquiry = kmalloc(sdev->inquiry_len, GFP_ATOMIC);
624 	if (sdev->inquiry == NULL) {
625 		return SCSI_SCAN_NO_RESPONSE;
626 	}
627 
628 	memcpy(sdev->inquiry, inq_result, sdev->inquiry_len);
629 	sdev->vendor = (char *) (sdev->inquiry + 8);
630 	sdev->model = (char *) (sdev->inquiry + 16);
631 	sdev->rev = (char *) (sdev->inquiry + 32);
632 
633 	if (*bflags & BLIST_ISROM) {
634 		/*
635 		 * It would be better to modify sdev->type, and set
636 		 * sdev->removable, but then the print_inquiry() output
637 		 * would not show TYPE_ROM; if print_inquiry() is removed
638 		 * the issue goes away.
639 		 */
640 		inq_result[0] = TYPE_ROM;
641 		inq_result[1] |= 0x80;	/* removable */
642 	} else if (*bflags & BLIST_NO_ULD_ATTACH)
643 		sdev->no_uld_attach = 1;
644 
645 	switch (sdev->type = (inq_result[0] & 0x1f)) {
646 	case TYPE_TAPE:
647 	case TYPE_DISK:
648 	case TYPE_PRINTER:
649 	case TYPE_MOD:
650 	case TYPE_PROCESSOR:
651 	case TYPE_SCANNER:
652 	case TYPE_MEDIUM_CHANGER:
653 	case TYPE_ENCLOSURE:
654 	case TYPE_COMM:
655 	case TYPE_RBC:
656 		sdev->writeable = 1;
657 		break;
658 	case TYPE_WORM:
659 	case TYPE_ROM:
660 		sdev->writeable = 0;
661 		break;
662 	default:
663 		printk(KERN_INFO "scsi: unknown device type %d\n", sdev->type);
664 	}
665 
666 	print_inquiry(inq_result);
667 
668 	/*
669 	 * For a peripheral qualifier (PQ) value of 1 (001b), the SCSI
670 	 * spec says: The device server is capable of supporting the
671 	 * specified peripheral device type on this logical unit. However,
672 	 * the physical device is not currently connected to this logical
673 	 * unit.
674 	 *
675 	 * The above is vague, as it implies that we could treat 001 and
676 	 * 011 the same. Stay compatible with previous code, and create a
677 	 * Scsi_Device for a PQ of 1
678 	 *
679 	 * Don't set the device offline here; rather let the upper
680 	 * level drivers eval the PQ to decide whether they should
681 	 * attach. So remove ((inq_result[0] >> 5) & 7) == 1 check.
682 	 */
683 
684 	sdev->inq_periph_qual = (inq_result[0] >> 5) & 7;
685 	sdev->removable = (0x80 & inq_result[1]) >> 7;
686 	sdev->lockable = sdev->removable;
687 	sdev->soft_reset = (inq_result[7] & 1) && ((inq_result[3] & 7) == 2);
688 
689 	if (sdev->scsi_level >= SCSI_3 || (sdev->inquiry_len > 56 &&
690 		inq_result[56] & 0x04))
691 		sdev->ppr = 1;
692 	if (inq_result[7] & 0x60)
693 		sdev->wdtr = 1;
694 	if (inq_result[7] & 0x10)
695 		sdev->sdtr = 1;
696 
697 	sprintf(sdev->devfs_name, "scsi/host%d/bus%d/target%d/lun%d",
698 				sdev->host->host_no, sdev->channel,
699 				sdev->id, sdev->lun);
700 
701 	/*
702 	 * End driverfs/devfs code.
703 	 */
704 
705 	if ((sdev->scsi_level >= SCSI_2) && (inq_result[7] & 2) &&
706 	    !(*bflags & BLIST_NOTQ))
707 		sdev->tagged_supported = 1;
708 	/*
709 	 * Some devices (Texel CD ROM drives) have handshaking problems
710 	 * when used with the Seagate controllers. borken is initialized
711 	 * to 1, and then set it to 0 here.
712 	 */
713 	if ((*bflags & BLIST_BORKEN) == 0)
714 		sdev->borken = 0;
715 
716 	/*
717 	 * Apparently some really broken devices (contrary to the SCSI
718 	 * standards) need to be selected without asserting ATN
719 	 */
720 	if (*bflags & BLIST_SELECT_NO_ATN)
721 		sdev->select_no_atn = 1;
722 
723 	/*
724 	 * Some devices may not want to have a start command automatically
725 	 * issued when a device is added.
726 	 */
727 	if (*bflags & BLIST_NOSTARTONADD)
728 		sdev->no_start_on_add = 1;
729 
730 	if (*bflags & BLIST_SINGLELUN)
731 		sdev->single_lun = 1;
732 
733 
734 	sdev->use_10_for_rw = 1;
735 
736 	if (*bflags & BLIST_MS_SKIP_PAGE_08)
737 		sdev->skip_ms_page_8 = 1;
738 
739 	if (*bflags & BLIST_MS_SKIP_PAGE_3F)
740 		sdev->skip_ms_page_3f = 1;
741 
742 	if (*bflags & BLIST_USE_10_BYTE_MS)
743 		sdev->use_10_for_ms = 1;
744 
745 	/* set the device running here so that slave configure
746 	 * may do I/O */
747 	scsi_device_set_state(sdev, SDEV_RUNNING);
748 
749 	if (*bflags & BLIST_MS_192_BYTES_FOR_3F)
750 		sdev->use_192_bytes_for_3f = 1;
751 
752 	if (*bflags & BLIST_NOT_LOCKABLE)
753 		sdev->lockable = 0;
754 
755 	if (*bflags & BLIST_RETRY_HWERROR)
756 		sdev->retry_hwerror = 1;
757 
758 	transport_configure_device(&sdev->sdev_gendev);
759 
760 	if (sdev->host->hostt->slave_configure)
761 		sdev->host->hostt->slave_configure(sdev);
762 
763 	/*
764 	 * Ok, the device is now all set up, we can
765 	 * register it and tell the rest of the kernel
766 	 * about it.
767 	 */
768 	if (scsi_sysfs_add_sdev(sdev) != 0)
769 		return SCSI_SCAN_NO_RESPONSE;
770 
771 	return SCSI_SCAN_LUN_PRESENT;
772 }
773 
774 /**
775  * scsi_probe_and_add_lun - probe a LUN, if a LUN is found add it
776  * @starget:	pointer to target device structure
777  * @lun:	LUN of target device
778  * @sdevscan:	probe the LUN corresponding to this Scsi_Device
779  * @sdevnew:	store the value of any new Scsi_Device allocated
780  * @bflagsp:	store bflags here if not NULL
781  *
782  * Description:
783  *     Call scsi_probe_lun, if a LUN with an attached device is found,
784  *     allocate and set it up by calling scsi_add_lun.
785  *
786  * Return:
787  *     SCSI_SCAN_NO_RESPONSE: could not allocate or setup a Scsi_Device
788  *     SCSI_SCAN_TARGET_PRESENT: target responded, but no device is
789  *         attached at the LUN
790  *     SCSI_SCAN_LUN_PRESENT: a new Scsi_Device was allocated and initialized
791  **/
792 static int scsi_probe_and_add_lun(struct scsi_target *starget,
793 				  uint lun, int *bflagsp,
794 				  struct scsi_device **sdevp, int rescan,
795 				  void *hostdata)
796 {
797 	struct scsi_device *sdev;
798 	unsigned char *result;
799 	int bflags, res = SCSI_SCAN_NO_RESPONSE, result_len = 256;
800 	struct Scsi_Host *shost = dev_to_shost(starget->dev.parent);
801 
802 	/*
803 	 * The rescan flag is used as an optimization, the first scan of a
804 	 * host adapter calls into here with rescan == 0.
805 	 */
806 	if (rescan) {
807 		sdev = scsi_device_lookup_by_target(starget, lun);
808 		if (sdev) {
809 			SCSI_LOG_SCAN_BUS(3, printk(KERN_INFO
810 				"scsi scan: device exists on %s\n",
811 				sdev->sdev_gendev.bus_id));
812 			if (sdevp)
813 				*sdevp = sdev;
814 			else
815 				scsi_device_put(sdev);
816 
817 			if (bflagsp)
818 				*bflagsp = scsi_get_device_flags(sdev,
819 								 sdev->vendor,
820 								 sdev->model);
821 			return SCSI_SCAN_LUN_PRESENT;
822 		}
823 	}
824 
825 	sdev = scsi_alloc_sdev(starget, lun, hostdata);
826 	if (!sdev)
827 		goto out;
828 
829 	result = kmalloc(result_len, GFP_ATOMIC |
830 			((shost->unchecked_isa_dma) ? __GFP_DMA : 0));
831 	if (!result)
832 		goto out_free_sdev;
833 
834 	if (scsi_probe_lun(sdev, result, result_len, &bflags))
835 		goto out_free_result;
836 
837 	/*
838 	 * result contains valid SCSI INQUIRY data.
839 	 */
840 	if ((result[0] >> 5) == 3) {
841 		/*
842 		 * For a Peripheral qualifier 3 (011b), the SCSI
843 		 * spec says: The device server is not capable of
844 		 * supporting a physical device on this logical
845 		 * unit.
846 		 *
847 		 * For disks, this implies that there is no
848 		 * logical disk configured at sdev->lun, but there
849 		 * is a target id responding.
850 		 */
851 		SCSI_LOG_SCAN_BUS(3, printk(KERN_INFO
852 					"scsi scan: peripheral qualifier of 3,"
853 					" no device added\n"));
854 		res = SCSI_SCAN_TARGET_PRESENT;
855 		goto out_free_result;
856 	}
857 
858 	res = scsi_add_lun(sdev, result, &bflags);
859 	if (res == SCSI_SCAN_LUN_PRESENT) {
860 		if (bflags & BLIST_KEY) {
861 			sdev->lockable = 0;
862 			scsi_unlock_floptical(sdev, result);
863 		}
864 		if (bflagsp)
865 			*bflagsp = bflags;
866 	}
867 
868  out_free_result:
869 	kfree(result);
870  out_free_sdev:
871 	if (res == SCSI_SCAN_LUN_PRESENT) {
872 		if (sdevp) {
873 			scsi_device_get(sdev);
874 			*sdevp = sdev;
875 		}
876 	} else {
877 		if (sdev->host->hostt->slave_destroy)
878 			sdev->host->hostt->slave_destroy(sdev);
879 		transport_destroy_device(&sdev->sdev_gendev);
880 		put_device(&sdev->sdev_gendev);
881 	}
882  out:
883 	return res;
884 }
885 
886 /**
887  * scsi_sequential_lun_scan - sequentially scan a SCSI target
888  * @starget:	pointer to target structure to scan
889  * @bflags:	black/white list flag for LUN 0
890  * @lun0_res:	result of scanning LUN 0
891  *
892  * Description:
893  *     Generally, scan from LUN 1 (LUN 0 is assumed to already have been
894  *     scanned) to some maximum lun until a LUN is found with no device
895  *     attached. Use the bflags to figure out any oddities.
896  *
897  *     Modifies sdevscan->lun.
898  **/
899 static void scsi_sequential_lun_scan(struct scsi_target *starget,
900 				     int bflags, int lun0_res, int scsi_level,
901 				     int rescan)
902 {
903 	unsigned int sparse_lun, lun, max_dev_lun;
904 	struct Scsi_Host *shost = dev_to_shost(starget->dev.parent);
905 
906 	SCSI_LOG_SCAN_BUS(3, printk(KERN_INFO "scsi scan: Sequential scan of"
907 				    "%s\n", starget->dev.bus_id));
908 
909 	max_dev_lun = min(max_scsi_luns, shost->max_lun);
910 	/*
911 	 * If this device is known to support sparse multiple units,
912 	 * override the other settings, and scan all of them. Normally,
913 	 * SCSI-3 devices should be scanned via the REPORT LUNS.
914 	 */
915 	if (bflags & BLIST_SPARSELUN) {
916 		max_dev_lun = shost->max_lun;
917 		sparse_lun = 1;
918 	} else
919 		sparse_lun = 0;
920 
921 	/*
922 	 * If not sparse lun and no device attached at LUN 0 do not scan
923 	 * any further.
924 	 */
925 	if (!sparse_lun && (lun0_res != SCSI_SCAN_LUN_PRESENT))
926 		return;
927 
928 	/*
929 	 * If less than SCSI_1_CSS, and no special lun scaning, stop
930 	 * scanning; this matches 2.4 behaviour, but could just be a bug
931 	 * (to continue scanning a SCSI_1_CSS device).
932 	 *
933 	 * This test is broken.  We might not have any device on lun0 for
934 	 * a sparselun device, and if that's the case then how would we
935 	 * know the real scsi_level, eh?  It might make sense to just not
936 	 * scan any SCSI_1 device for non-0 luns, but that check would best
937 	 * go into scsi_alloc_sdev() and just have it return null when asked
938 	 * to alloc an sdev for lun > 0 on an already found SCSI_1 device.
939 	 *
940 	if ((sdevscan->scsi_level < SCSI_1_CCS) &&
941 	    ((bflags & (BLIST_FORCELUN | BLIST_SPARSELUN | BLIST_MAX5LUN))
942 	     == 0))
943 		return;
944 	 */
945 	/*
946 	 * If this device is known to support multiple units, override
947 	 * the other settings, and scan all of them.
948 	 */
949 	if (bflags & BLIST_FORCELUN)
950 		max_dev_lun = shost->max_lun;
951 	/*
952 	 * REGAL CDC-4X: avoid hang after LUN 4
953 	 */
954 	if (bflags & BLIST_MAX5LUN)
955 		max_dev_lun = min(5U, max_dev_lun);
956 	/*
957 	 * Do not scan SCSI-2 or lower device past LUN 7, unless
958 	 * BLIST_LARGELUN.
959 	 */
960 	if (scsi_level < SCSI_3 && !(bflags & BLIST_LARGELUN))
961 		max_dev_lun = min(8U, max_dev_lun);
962 
963 	/*
964 	 * We have already scanned LUN 0, so start at LUN 1. Keep scanning
965 	 * until we reach the max, or no LUN is found and we are not
966 	 * sparse_lun.
967 	 */
968 	for (lun = 1; lun < max_dev_lun; ++lun)
969 		if ((scsi_probe_and_add_lun(starget, lun, NULL, NULL, rescan,
970 					    NULL) != SCSI_SCAN_LUN_PRESENT) &&
971 		    !sparse_lun)
972 			return;
973 }
974 
975 /**
976  * scsilun_to_int: convert a scsi_lun to an int
977  * @scsilun:	struct scsi_lun to be converted.
978  *
979  * Description:
980  *     Convert @scsilun from a struct scsi_lun to a four byte host byte-ordered
981  *     integer, and return the result. The caller must check for
982  *     truncation before using this function.
983  *
984  * Notes:
985  *     The struct scsi_lun is assumed to be four levels, with each level
986  *     effectively containing a SCSI byte-ordered (big endian) short; the
987  *     addressing bits of each level are ignored (the highest two bits).
988  *     For a description of the LUN format, post SCSI-3 see the SCSI
989  *     Architecture Model, for SCSI-3 see the SCSI Controller Commands.
990  *
991  *     Given a struct scsi_lun of: 0a 04 0b 03 00 00 00 00, this function returns
992  *     the integer: 0x0b030a04
993  **/
994 static int scsilun_to_int(struct scsi_lun *scsilun)
995 {
996 	int i;
997 	unsigned int lun;
998 
999 	lun = 0;
1000 	for (i = 0; i < sizeof(lun); i += 2)
1001 		lun = lun | (((scsilun->scsi_lun[i] << 8) |
1002 			      scsilun->scsi_lun[i + 1]) << (i * 8));
1003 	return lun;
1004 }
1005 
1006 /**
1007  * int_to_scsilun: reverts an int into a scsi_lun
1008  * @int:        integer to be reverted
1009  * @scsilun:	struct scsi_lun to be set.
1010  *
1011  * Description:
1012  *     Reverts the functionality of the scsilun_to_int, which packed
1013  *     an 8-byte lun value into an int. This routine unpacks the int
1014  *     back into the lun value.
1015  *     Note: the scsilun_to_int() routine does not truly handle all
1016  *     8bytes of the lun value. This functions restores only as much
1017  *     as was set by the routine.
1018  *
1019  * Notes:
1020  *     Given an integer : 0x0b030a04,  this function returns a
1021  *     scsi_lun of : struct scsi_lun of: 0a 04 0b 03 00 00 00 00
1022  *
1023  **/
1024 void int_to_scsilun(unsigned int lun, struct scsi_lun *scsilun)
1025 {
1026 	int i;
1027 
1028 	memset(scsilun->scsi_lun, 0, sizeof(scsilun->scsi_lun));
1029 
1030 	for (i = 0; i < sizeof(lun); i += 2) {
1031 		scsilun->scsi_lun[i] = (lun >> 8) & 0xFF;
1032 		scsilun->scsi_lun[i+1] = lun & 0xFF;
1033 		lun = lun >> 16;
1034 	}
1035 }
1036 EXPORT_SYMBOL(int_to_scsilun);
1037 
1038 /**
1039  * scsi_report_lun_scan - Scan using SCSI REPORT LUN results
1040  * @sdevscan:	scan the host, channel, and id of this Scsi_Device
1041  *
1042  * Description:
1043  *     If @sdevscan is for a SCSI-3 or up device, send a REPORT LUN
1044  *     command, and scan the resulting list of LUNs by calling
1045  *     scsi_probe_and_add_lun.
1046  *
1047  *     Modifies sdevscan->lun.
1048  *
1049  * Return:
1050  *     0: scan completed (or no memory, so further scanning is futile)
1051  *     1: no report lun scan, or not configured
1052  **/
1053 static int scsi_report_lun_scan(struct scsi_device *sdev, int bflags,
1054 				int rescan)
1055 {
1056 	char devname[64];
1057 	unsigned char scsi_cmd[MAX_COMMAND_SIZE];
1058 	unsigned int length;
1059 	unsigned int lun;
1060 	unsigned int num_luns;
1061 	unsigned int retries;
1062 	int result;
1063 	struct scsi_lun *lunp, *lun_data;
1064 	u8 *data;
1065 	struct scsi_sense_hdr sshdr;
1066 	struct scsi_target *starget = scsi_target(sdev);
1067 
1068 	/*
1069 	 * Only support SCSI-3 and up devices if BLIST_NOREPORTLUN is not set.
1070 	 * Also allow SCSI-2 if BLIST_REPORTLUN2 is set and host adapter does
1071 	 * support more than 8 LUNs.
1072 	 */
1073 	if ((bflags & BLIST_NOREPORTLUN) ||
1074 	     sdev->scsi_level < SCSI_2 ||
1075 	    (sdev->scsi_level < SCSI_3 &&
1076 	     (!(bflags & BLIST_REPORTLUN2) || sdev->host->max_lun <= 8)) )
1077 		return 1;
1078 	if (bflags & BLIST_NOLUN)
1079 		return 0;
1080 
1081 	sprintf(devname, "host %d channel %d id %d",
1082 		sdev->host->host_no, sdev->channel, sdev->id);
1083 
1084 	/*
1085 	 * Allocate enough to hold the header (the same size as one scsi_lun)
1086 	 * plus the max number of luns we are requesting.
1087 	 *
1088 	 * Reallocating and trying again (with the exact amount we need)
1089 	 * would be nice, but then we need to somehow limit the size
1090 	 * allocated based on the available memory and the limits of
1091 	 * kmalloc - we don't want a kmalloc() failure of a huge value to
1092 	 * prevent us from finding any LUNs on this target.
1093 	 */
1094 	length = (max_scsi_report_luns + 1) * sizeof(struct scsi_lun);
1095 	lun_data = kmalloc(length, GFP_ATOMIC |
1096 			   (sdev->host->unchecked_isa_dma ? __GFP_DMA : 0));
1097 	if (!lun_data)
1098 		goto out;
1099 
1100 	scsi_cmd[0] = REPORT_LUNS;
1101 
1102 	/*
1103 	 * bytes 1 - 5: reserved, set to zero.
1104 	 */
1105 	memset(&scsi_cmd[1], 0, 5);
1106 
1107 	/*
1108 	 * bytes 6 - 9: length of the command.
1109 	 */
1110 	scsi_cmd[6] = (unsigned char) (length >> 24) & 0xff;
1111 	scsi_cmd[7] = (unsigned char) (length >> 16) & 0xff;
1112 	scsi_cmd[8] = (unsigned char) (length >> 8) & 0xff;
1113 	scsi_cmd[9] = (unsigned char) length & 0xff;
1114 
1115 	scsi_cmd[10] = 0;	/* reserved */
1116 	scsi_cmd[11] = 0;	/* control */
1117 
1118 	/*
1119 	 * We can get a UNIT ATTENTION, for example a power on/reset, so
1120 	 * retry a few times (like sd.c does for TEST UNIT READY).
1121 	 * Experience shows some combinations of adapter/devices get at
1122 	 * least two power on/resets.
1123 	 *
1124 	 * Illegal requests (for devices that do not support REPORT LUNS)
1125 	 * should come through as a check condition, and will not generate
1126 	 * a retry.
1127 	 */
1128 	for (retries = 0; retries < 3; retries++) {
1129 		SCSI_LOG_SCAN_BUS(3, printk (KERN_INFO "scsi scan: Sending"
1130 				" REPORT LUNS to %s (try %d)\n", devname,
1131 				retries));
1132 
1133 		result = scsi_execute_req(sdev, scsi_cmd, DMA_FROM_DEVICE,
1134 					  lun_data, length, &sshdr,
1135 					  SCSI_TIMEOUT + 4 * HZ, 3);
1136 
1137 		SCSI_LOG_SCAN_BUS(3, printk (KERN_INFO "scsi scan: REPORT LUNS"
1138 				" %s (try %d) result 0x%x\n", result
1139 				?  "failed" : "successful", retries, result));
1140 		if (result == 0)
1141 			break;
1142 		else if (scsi_sense_valid(&sshdr)) {
1143 			if (sshdr.sense_key != UNIT_ATTENTION)
1144 				break;
1145 		}
1146 	}
1147 
1148 	if (result) {
1149 		/*
1150 		 * The device probably does not support a REPORT LUN command
1151 		 */
1152 		kfree(lun_data);
1153 		return 1;
1154 	}
1155 
1156 	/*
1157 	 * Get the length from the first four bytes of lun_data.
1158 	 */
1159 	data = (u8 *) lun_data->scsi_lun;
1160 	length = ((data[0] << 24) | (data[1] << 16) |
1161 		  (data[2] << 8) | (data[3] << 0));
1162 
1163 	num_luns = (length / sizeof(struct scsi_lun));
1164 	if (num_luns > max_scsi_report_luns) {
1165 		printk(KERN_WARNING "scsi: On %s only %d (max_scsi_report_luns)"
1166 		       " of %d luns reported, try increasing"
1167 		       " max_scsi_report_luns.\n", devname,
1168 		       max_scsi_report_luns, num_luns);
1169 		num_luns = max_scsi_report_luns;
1170 	}
1171 
1172 	SCSI_LOG_SCAN_BUS(3, printk (KERN_INFO "scsi scan: REPORT LUN scan of"
1173 			" host %d channel %d id %d\n", sdev->host->host_no,
1174 			sdev->channel, sdev->id));
1175 
1176 	/*
1177 	 * Scan the luns in lun_data. The entry at offset 0 is really
1178 	 * the header, so start at 1 and go up to and including num_luns.
1179 	 */
1180 	for (lunp = &lun_data[1]; lunp <= &lun_data[num_luns]; lunp++) {
1181 		lun = scsilun_to_int(lunp);
1182 
1183 		/*
1184 		 * Check if the unused part of lunp is non-zero, and so
1185 		 * does not fit in lun.
1186 		 */
1187 		if (memcmp(&lunp->scsi_lun[sizeof(lun)], "\0\0\0\0", 4)) {
1188 			int i;
1189 
1190 			/*
1191 			 * Output an error displaying the LUN in byte order,
1192 			 * this differs from what linux would print for the
1193 			 * integer LUN value.
1194 			 */
1195 			printk(KERN_WARNING "scsi: %s lun 0x", devname);
1196 			data = (char *)lunp->scsi_lun;
1197 			for (i = 0; i < sizeof(struct scsi_lun); i++)
1198 				printk("%02x", data[i]);
1199 			printk(" has a LUN larger than currently supported.\n");
1200 		} else if (lun == 0) {
1201 			/*
1202 			 * LUN 0 has already been scanned.
1203 			 */
1204 		} else if (lun > sdev->host->max_lun) {
1205 			printk(KERN_WARNING "scsi: %s lun%d has a LUN larger"
1206 			       " than allowed by the host adapter\n",
1207 			       devname, lun);
1208 		} else {
1209 			int res;
1210 
1211 			res = scsi_probe_and_add_lun(starget,
1212 				lun, NULL, NULL, rescan, NULL);
1213 			if (res == SCSI_SCAN_NO_RESPONSE) {
1214 				/*
1215 				 * Got some results, but now none, abort.
1216 				 */
1217 				printk(KERN_ERR "scsi: Unexpected response"
1218 				       " from %s lun %d while scanning, scan"
1219 				       " aborted\n", devname, lun);
1220 				break;
1221 			}
1222 		}
1223 	}
1224 
1225 	kfree(lun_data);
1226 	return 0;
1227 
1228  out:
1229 	/*
1230 	 * We are out of memory, don't try scanning any further.
1231 	 */
1232 	printk(ALLOC_FAILURE_MSG, __FUNCTION__);
1233 	return 0;
1234 }
1235 
1236 struct scsi_device *__scsi_add_device(struct Scsi_Host *shost, uint channel,
1237 				      uint id, uint lun, void *hostdata)
1238 {
1239 	struct scsi_device *sdev;
1240 	struct device *parent = &shost->shost_gendev;
1241 	int res;
1242 	struct scsi_target *starget = scsi_alloc_target(parent, channel, id);
1243 
1244 	if (!starget)
1245 		return ERR_PTR(-ENOMEM);
1246 
1247 	get_device(&starget->dev);
1248 	down(&shost->scan_mutex);
1249 	if (scsi_host_scan_allowed(shost)) {
1250 		res = scsi_probe_and_add_lun(starget, lun, NULL, &sdev, 1,
1251 					     hostdata);
1252 		if (res != SCSI_SCAN_LUN_PRESENT)
1253 			sdev = ERR_PTR(-ENODEV);
1254 	}
1255 	up(&shost->scan_mutex);
1256 	scsi_target_reap(starget);
1257 	put_device(&starget->dev);
1258 
1259 	return sdev;
1260 }
1261 EXPORT_SYMBOL(__scsi_add_device);
1262 
1263 void scsi_rescan_device(struct device *dev)
1264 {
1265 	struct scsi_driver *drv;
1266 
1267 	if (!dev->driver)
1268 		return;
1269 
1270 	drv = to_scsi_driver(dev->driver);
1271 	if (try_module_get(drv->owner)) {
1272 		if (drv->rescan)
1273 			drv->rescan(dev);
1274 		module_put(drv->owner);
1275 	}
1276 }
1277 EXPORT_SYMBOL(scsi_rescan_device);
1278 
1279 /**
1280  * scsi_scan_target - scan a target id, possibly including all LUNs on the
1281  *     target.
1282  * @sdevsca:	Scsi_Device handle for scanning
1283  * @shost:	host to scan
1284  * @channel:	channel to scan
1285  * @id:		target id to scan
1286  *
1287  * Description:
1288  *     Scan the target id on @shost, @channel, and @id. Scan at least LUN
1289  *     0, and possibly all LUNs on the target id.
1290  *
1291  *     Use the pre-allocated @sdevscan as a handle for the scanning. This
1292  *     function sets sdevscan->host, sdevscan->id and sdevscan->lun; the
1293  *     scanning functions modify sdevscan->lun.
1294  *
1295  *     First try a REPORT LUN scan, if that does not scan the target, do a
1296  *     sequential scan of LUNs on the target id.
1297  **/
1298 void scsi_scan_target(struct device *parent, unsigned int channel,
1299 		      unsigned int id, unsigned int lun, int rescan)
1300 {
1301 	struct Scsi_Host *shost = dev_to_shost(parent);
1302 	int bflags = 0;
1303 	int res;
1304 	struct scsi_device *sdev = NULL;
1305 	struct scsi_target *starget;
1306 
1307 	if (shost->this_id == id)
1308 		/*
1309 		 * Don't scan the host adapter
1310 		 */
1311 		return;
1312 
1313 
1314 	starget = scsi_alloc_target(parent, channel, id);
1315 
1316 	if (!starget)
1317 		return;
1318 
1319 	get_device(&starget->dev);
1320 	if (lun != SCAN_WILD_CARD) {
1321 		/*
1322 		 * Scan for a specific host/chan/id/lun.
1323 		 */
1324 		scsi_probe_and_add_lun(starget, lun, NULL, NULL, rescan, NULL);
1325 		goto out_reap;
1326 	}
1327 
1328 	/*
1329 	 * Scan LUN 0, if there is some response, scan further. Ideally, we
1330 	 * would not configure LUN 0 until all LUNs are scanned.
1331 	 */
1332 	res = scsi_probe_and_add_lun(starget, 0, &bflags, &sdev, rescan, NULL);
1333 	if (res == SCSI_SCAN_LUN_PRESENT) {
1334 		if (scsi_report_lun_scan(sdev, bflags, rescan) != 0)
1335 			/*
1336 			 * The REPORT LUN did not scan the target,
1337 			 * do a sequential scan.
1338 			 */
1339 			scsi_sequential_lun_scan(starget, bflags,
1340 				       	res, sdev->scsi_level, rescan);
1341 	} else if (res == SCSI_SCAN_TARGET_PRESENT) {
1342 		/*
1343 		 * There's a target here, but lun 0 is offline so we
1344 		 * can't use the report_lun scan.  Fall back to a
1345 		 * sequential lun scan with a bflags of SPARSELUN and
1346 		 * a default scsi level of SCSI_2
1347 		 */
1348 		scsi_sequential_lun_scan(starget, BLIST_SPARSELUN,
1349 				SCSI_SCAN_TARGET_PRESENT, SCSI_2, rescan);
1350 	}
1351 	if (sdev)
1352 		scsi_device_put(sdev);
1353 
1354  out_reap:
1355 	/* now determine if the target has any children at all
1356 	 * and if not, nuke it */
1357 	scsi_target_reap(starget);
1358 
1359 	put_device(&starget->dev);
1360 }
1361 EXPORT_SYMBOL(scsi_scan_target);
1362 
1363 static void scsi_scan_channel(struct Scsi_Host *shost, unsigned int channel,
1364 			      unsigned int id, unsigned int lun, int rescan)
1365 {
1366 	uint order_id;
1367 
1368 	if (id == SCAN_WILD_CARD)
1369 		for (id = 0; id < shost->max_id; ++id) {
1370 			/*
1371 			 * XXX adapter drivers when possible (FCP, iSCSI)
1372 			 * could modify max_id to match the current max,
1373 			 * not the absolute max.
1374 			 *
1375 			 * XXX add a shost id iterator, so for example,
1376 			 * the FC ID can be the same as a target id
1377 			 * without a huge overhead of sparse id's.
1378 			 */
1379 			if (shost->reverse_ordering)
1380 				/*
1381 				 * Scan from high to low id.
1382 				 */
1383 				order_id = shost->max_id - id - 1;
1384 			else
1385 				order_id = id;
1386 			scsi_scan_target(&shost->shost_gendev, channel, order_id, lun, rescan);
1387 		}
1388 	else
1389 		scsi_scan_target(&shost->shost_gendev, channel, id, lun, rescan);
1390 }
1391 
1392 int scsi_scan_host_selected(struct Scsi_Host *shost, unsigned int channel,
1393 			    unsigned int id, unsigned int lun, int rescan)
1394 {
1395 	SCSI_LOG_SCAN_BUS(3, printk (KERN_INFO "%s: <%u:%u:%u:%u>\n",
1396 		__FUNCTION__, shost->host_no, channel, id, lun));
1397 
1398 	if (((channel != SCAN_WILD_CARD) && (channel > shost->max_channel)) ||
1399 	    ((id != SCAN_WILD_CARD) && (id > shost->max_id)) ||
1400 	    ((lun != SCAN_WILD_CARD) && (lun > shost->max_lun)))
1401 		return -EINVAL;
1402 
1403 	down(&shost->scan_mutex);
1404 	if (scsi_host_scan_allowed(shost)) {
1405 		if (channel == SCAN_WILD_CARD)
1406 			for (channel = 0; channel <= shost->max_channel;
1407 			     channel++)
1408 				scsi_scan_channel(shost, channel, id, lun,
1409 						  rescan);
1410 		else
1411 			scsi_scan_channel(shost, channel, id, lun, rescan);
1412 	}
1413 	up(&shost->scan_mutex);
1414 
1415 	return 0;
1416 }
1417 
1418 /**
1419  * scsi_scan_host - scan the given adapter
1420  * @shost:	adapter to scan
1421  **/
1422 void scsi_scan_host(struct Scsi_Host *shost)
1423 {
1424 	scsi_scan_host_selected(shost, SCAN_WILD_CARD, SCAN_WILD_CARD,
1425 				SCAN_WILD_CARD, 0);
1426 }
1427 EXPORT_SYMBOL(scsi_scan_host);
1428 
1429 /**
1430  * scsi_scan_single_target - scan the given SCSI target
1431  * @shost:         adapter to scan
1432  * @chan:          channel to scan
1433  * @id:            target id to scan
1434  **/
1435 void scsi_scan_single_target(struct Scsi_Host *shost,
1436 	unsigned int chan, unsigned int id)
1437 {
1438 	scsi_scan_host_selected(shost, chan, id, SCAN_WILD_CARD, 1);
1439 }
1440 EXPORT_SYMBOL(scsi_scan_single_target);
1441 
1442 void scsi_forget_host(struct Scsi_Host *shost)
1443 {
1444 	struct scsi_target *starget, *tmp;
1445 	unsigned long flags;
1446 
1447 	/*
1448 	 * Ok, this look a bit strange.  We always look for the first device
1449 	 * on the list as scsi_remove_device removes them from it - thus we
1450 	 * also have to release the lock.
1451 	 * We don't need to get another reference to the device before
1452 	 * releasing the lock as we already own the reference from
1453 	 * scsi_register_device that's release in scsi_remove_device.  And
1454 	 * after that we don't look at sdev anymore.
1455 	 */
1456 	spin_lock_irqsave(shost->host_lock, flags);
1457 	list_for_each_entry_safe(starget, tmp, &shost->__targets, siblings) {
1458 		spin_unlock_irqrestore(shost->host_lock, flags);
1459 		scsi_remove_target(&starget->dev);
1460 		spin_lock_irqsave(shost->host_lock, flags);
1461 	}
1462 	spin_unlock_irqrestore(shost->host_lock, flags);
1463 }
1464 
1465 /*
1466  * Function:    scsi_get_host_dev()
1467  *
1468  * Purpose:     Create a Scsi_Device that points to the host adapter itself.
1469  *
1470  * Arguments:   SHpnt   - Host that needs a Scsi_Device
1471  *
1472  * Lock status: None assumed.
1473  *
1474  * Returns:     The Scsi_Device or NULL
1475  *
1476  * Notes:
1477  *	Attach a single Scsi_Device to the Scsi_Host - this should
1478  *	be made to look like a "pseudo-device" that points to the
1479  *	HA itself.
1480  *
1481  *	Note - this device is not accessible from any high-level
1482  *	drivers (including generics), which is probably not
1483  *	optimal.  We can add hooks later to attach
1484  */
1485 struct scsi_device *scsi_get_host_dev(struct Scsi_Host *shost)
1486 {
1487 	struct scsi_device *sdev;
1488 	struct scsi_target *starget;
1489 
1490 	starget = scsi_alloc_target(&shost->shost_gendev, 0, shost->this_id);
1491 	if (!starget)
1492 		return NULL;
1493 
1494 	sdev = scsi_alloc_sdev(starget, 0, NULL);
1495 	if (sdev) {
1496 		sdev->sdev_gendev.parent = get_device(&starget->dev);
1497 		sdev->borken = 0;
1498 	}
1499 	put_device(&starget->dev);
1500 	return sdev;
1501 }
1502 EXPORT_SYMBOL(scsi_get_host_dev);
1503 
1504 /*
1505  * Function:    scsi_free_host_dev()
1506  *
1507  * Purpose:     Free a scsi_device that points to the host adapter itself.
1508  *
1509  * Arguments:   SHpnt   - Host that needs a Scsi_Device
1510  *
1511  * Lock status: None assumed.
1512  *
1513  * Returns:     Nothing
1514  *
1515  * Notes:
1516  */
1517 void scsi_free_host_dev(struct scsi_device *sdev)
1518 {
1519 	BUG_ON(sdev->id != sdev->host->this_id);
1520 
1521 	if (sdev->host->hostt->slave_destroy)
1522 		sdev->host->hostt->slave_destroy(sdev);
1523 	transport_destroy_device(&sdev->sdev_gendev);
1524 	put_device(&sdev->sdev_gendev);
1525 }
1526 EXPORT_SYMBOL(scsi_free_host_dev);
1527 
1528