xref: /linux/drivers/scsi/scsi_scan.c (revision 7b12b9137930eb821b68e1bfa11e9de692208620)
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 = kzalloc(sizeof(*sdev) + shost->transportt->device_size,
209 		       GFP_ATOMIC);
210 	if (!sdev)
211 		goto out;
212 
213 	sdev->vendor = scsi_null_device_strs;
214 	sdev->model = scsi_null_device_strs;
215 	sdev->rev = scsi_null_device_strs;
216 	sdev->host = shost;
217 	sdev->id = starget->id;
218 	sdev->lun = lun;
219 	sdev->channel = starget->channel;
220 	sdev->sdev_state = SDEV_CREATED;
221 	INIT_LIST_HEAD(&sdev->siblings);
222 	INIT_LIST_HEAD(&sdev->same_target_siblings);
223 	INIT_LIST_HEAD(&sdev->cmd_list);
224 	INIT_LIST_HEAD(&sdev->starved_entry);
225 	spin_lock_init(&sdev->list_lock);
226 
227 	sdev->sdev_gendev.parent = get_device(&starget->dev);
228 	sdev->sdev_target = starget;
229 
230 	/* usually NULL and set by ->slave_alloc instead */
231 	sdev->hostdata = hostdata;
232 
233 	/* if the device needs this changing, it may do so in the
234 	 * slave_configure function */
235 	sdev->max_device_blocked = SCSI_DEFAULT_DEVICE_BLOCKED;
236 
237 	/*
238 	 * Some low level driver could use device->type
239 	 */
240 	sdev->type = -1;
241 
242 	/*
243 	 * Assume that the device will have handshaking problems,
244 	 * and then fix this field later if it turns out it
245 	 * doesn't
246 	 */
247 	sdev->borken = 1;
248 
249 	sdev->request_queue = scsi_alloc_queue(sdev);
250 	if (!sdev->request_queue) {
251 		/* release fn is set up in scsi_sysfs_device_initialise, so
252 		 * have to free and put manually here */
253 		put_device(&starget->dev);
254 		kfree(sdev);
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 
292 	kfree(starget);
293 	put_device(parent);
294 }
295 
296 int scsi_is_target_device(const struct device *dev)
297 {
298 	return dev->release == scsi_target_dev_release;
299 }
300 EXPORT_SYMBOL(scsi_is_target_device);
301 
302 static struct scsi_target *__scsi_find_target(struct device *parent,
303 					      int channel, uint id)
304 {
305 	struct scsi_target *starget, *found_starget = NULL;
306 	struct Scsi_Host *shost = dev_to_shost(parent);
307 	/*
308 	 * Search for an existing target for this sdev.
309 	 */
310 	list_for_each_entry(starget, &shost->__targets, siblings) {
311 		if (starget->id == id &&
312 		    starget->channel == channel) {
313 			found_starget = starget;
314 			break;
315 		}
316 	}
317 	if (found_starget)
318 		get_device(&found_starget->dev);
319 
320 	return found_starget;
321 }
322 
323 static struct scsi_target *scsi_alloc_target(struct device *parent,
324 					     int channel, uint id)
325 {
326 	struct Scsi_Host *shost = dev_to_shost(parent);
327 	struct device *dev = NULL;
328 	unsigned long flags;
329 	const int size = sizeof(struct scsi_target)
330 		+ shost->transportt->target_size;
331 	struct scsi_target *starget;
332 	struct scsi_target *found_target;
333 	int error;
334 
335 	starget = kzalloc(size, GFP_KERNEL);
336 	if (!starget) {
337 		printk(KERN_ERR "%s: allocation failure\n", __FUNCTION__);
338 		return NULL;
339 	}
340 	dev = &starget->dev;
341 	device_initialize(dev);
342 	starget->reap_ref = 1;
343 	dev->parent = get_device(parent);
344 	dev->release = scsi_target_dev_release;
345 	sprintf(dev->bus_id, "target%d:%d:%d",
346 		shost->host_no, channel, id);
347 	starget->id = id;
348 	starget->channel = channel;
349 	INIT_LIST_HEAD(&starget->siblings);
350 	INIT_LIST_HEAD(&starget->devices);
351 	starget->state = STARGET_RUNNING;
352  retry:
353 	spin_lock_irqsave(shost->host_lock, flags);
354 
355 	found_target = __scsi_find_target(parent, channel, id);
356 	if (found_target)
357 		goto found;
358 
359 	list_add_tail(&starget->siblings, &shost->__targets);
360 	spin_unlock_irqrestore(shost->host_lock, flags);
361 	/* allocate and add */
362 	transport_setup_device(dev);
363 	error = device_add(dev);
364 	if (error) {
365 		dev_err(dev, "target device_add failed, error %d\n", error);
366 		spin_lock_irqsave(shost->host_lock, flags);
367 		list_del_init(&starget->siblings);
368 		spin_unlock_irqrestore(shost->host_lock, flags);
369 		transport_destroy_device(dev);
370 		put_device(parent);
371 		kfree(starget);
372 		return NULL;
373 	}
374 	transport_add_device(dev);
375 	if (shost->hostt->target_alloc) {
376 		error = shost->hostt->target_alloc(starget);
377 
378 		if(error) {
379 			dev_printk(KERN_ERR, dev, "target allocation failed, error %d\n", error);
380 			/* don't want scsi_target_reap to do the final
381 			 * put because it will be under the host lock */
382 			get_device(dev);
383 			scsi_target_reap(starget);
384 			put_device(dev);
385 			return NULL;
386 		}
387 	}
388 
389 	return starget;
390 
391  found:
392 	found_target->reap_ref++;
393 	spin_unlock_irqrestore(shost->host_lock, flags);
394 	put_device(parent);
395 	if (found_target->state != STARGET_DEL) {
396 		kfree(starget);
397 		return found_target;
398 	}
399 	/* Unfortunately, we found a dying target; need to
400 	 * wait until it's dead before we can get a new one */
401 	put_device(&found_target->dev);
402 	flush_scheduled_work();
403 	goto retry;
404 }
405 
406 static void scsi_target_reap_usercontext(void *data)
407 {
408 	struct scsi_target *starget = data;
409 	struct Scsi_Host *shost = dev_to_shost(starget->dev.parent);
410 	unsigned long flags;
411 
412 	transport_remove_device(&starget->dev);
413 	device_del(&starget->dev);
414 	transport_destroy_device(&starget->dev);
415 	spin_lock_irqsave(shost->host_lock, flags);
416 	if (shost->hostt->target_destroy)
417 		shost->hostt->target_destroy(starget);
418 	list_del_init(&starget->siblings);
419 	spin_unlock_irqrestore(shost->host_lock, flags);
420 	put_device(&starget->dev);
421 }
422 
423 /**
424  * scsi_target_reap - check to see if target is in use and destroy if not
425  *
426  * @starget: target to be checked
427  *
428  * This is used after removing a LUN or doing a last put of the target
429  * it checks atomically that nothing is using the target and removes
430  * it if so.
431  */
432 void scsi_target_reap(struct scsi_target *starget)
433 {
434 	struct Scsi_Host *shost = dev_to_shost(starget->dev.parent);
435 	unsigned long flags;
436 
437 	spin_lock_irqsave(shost->host_lock, flags);
438 
439 	if (--starget->reap_ref == 0 && list_empty(&starget->devices)) {
440 		BUG_ON(starget->state == STARGET_DEL);
441 		starget->state = STARGET_DEL;
442 		spin_unlock_irqrestore(shost->host_lock, flags);
443 		execute_in_process_context(scsi_target_reap_usercontext,
444 					   starget, &starget->ew);
445 		return;
446 
447 	}
448 	spin_unlock_irqrestore(shost->host_lock, flags);
449 
450 	return;
451 }
452 
453 /**
454  * scsi_probe_lun - probe a single LUN using a SCSI INQUIRY
455  * @sdev:	scsi_device to probe
456  * @inq_result:	area to store the INQUIRY result
457  * @result_len: len of inq_result
458  * @bflags:	store any bflags found here
459  *
460  * Description:
461  *     Probe the lun associated with @req using a standard SCSI INQUIRY;
462  *
463  *     If the INQUIRY is successful, zero is returned and the
464  *     INQUIRY data is in @inq_result; the scsi_level and INQUIRY length
465  *     are copied to the scsi_device any flags value is stored in *@bflags.
466  **/
467 static int scsi_probe_lun(struct scsi_device *sdev, char *inq_result,
468 			  int result_len, int *bflags)
469 {
470 	unsigned char scsi_cmd[MAX_COMMAND_SIZE];
471 	int first_inquiry_len, try_inquiry_len, next_inquiry_len;
472 	int response_len = 0;
473 	int pass, count, result;
474 	struct scsi_sense_hdr sshdr;
475 
476 	*bflags = 0;
477 
478 	/* Perform up to 3 passes.  The first pass uses a conservative
479 	 * transfer length of 36 unless sdev->inquiry_len specifies a
480 	 * different value. */
481 	first_inquiry_len = sdev->inquiry_len ? sdev->inquiry_len : 36;
482 	try_inquiry_len = first_inquiry_len;
483 	pass = 1;
484 
485  next_pass:
486 	SCSI_LOG_SCAN_BUS(3, sdev_printk(KERN_INFO, sdev,
487 				"scsi scan: INQUIRY pass %d length %d\n",
488 				pass, try_inquiry_len));
489 
490 	/* Each pass gets up to three chances to ignore Unit Attention */
491 	for (count = 0; count < 3; ++count) {
492 		memset(scsi_cmd, 0, 6);
493 		scsi_cmd[0] = INQUIRY;
494 		scsi_cmd[4] = (unsigned char) try_inquiry_len;
495 
496 		memset(inq_result, 0, try_inquiry_len);
497 
498 		result = scsi_execute_req(sdev,  scsi_cmd, DMA_FROM_DEVICE,
499 					  inq_result, try_inquiry_len, &sshdr,
500 					  HZ / 2 + HZ * scsi_inq_timeout, 3);
501 
502 		SCSI_LOG_SCAN_BUS(3, printk(KERN_INFO "scsi scan: INQUIRY %s "
503 				"with code 0x%x\n",
504 				result ? "failed" : "successful", result));
505 
506 		if (result) {
507 			/*
508 			 * not-ready to ready transition [asc/ascq=0x28/0x0]
509 			 * or power-on, reset [asc/ascq=0x29/0x0], continue.
510 			 * INQUIRY should not yield UNIT_ATTENTION
511 			 * but many buggy devices do so anyway.
512 			 */
513 			if ((driver_byte(result) & DRIVER_SENSE) &&
514 			    scsi_sense_valid(&sshdr)) {
515 				if ((sshdr.sense_key == UNIT_ATTENTION) &&
516 				    ((sshdr.asc == 0x28) ||
517 				     (sshdr.asc == 0x29)) &&
518 				    (sshdr.ascq == 0))
519 					continue;
520 			}
521 		}
522 		break;
523 	}
524 
525 	if (result == 0) {
526 		response_len = (unsigned char) inq_result[4] + 5;
527 		if (response_len > 255)
528 			response_len = first_inquiry_len;	/* sanity */
529 
530 		/*
531 		 * Get any flags for this device.
532 		 *
533 		 * XXX add a bflags to scsi_device, and replace the
534 		 * corresponding bit fields in scsi_device, so bflags
535 		 * need not be passed as an argument.
536 		 */
537 		*bflags = scsi_get_device_flags(sdev, &inq_result[8],
538 				&inq_result[16]);
539 
540 		/* When the first pass succeeds we gain information about
541 		 * what larger transfer lengths might work. */
542 		if (pass == 1) {
543 			if (BLIST_INQUIRY_36 & *bflags)
544 				next_inquiry_len = 36;
545 			else if (BLIST_INQUIRY_58 & *bflags)
546 				next_inquiry_len = 58;
547 			else if (sdev->inquiry_len)
548 				next_inquiry_len = sdev->inquiry_len;
549 			else
550 				next_inquiry_len = response_len;
551 
552 			/* If more data is available perform the second pass */
553 			if (next_inquiry_len > try_inquiry_len) {
554 				try_inquiry_len = next_inquiry_len;
555 				pass = 2;
556 				goto next_pass;
557 			}
558 		}
559 
560 	} else if (pass == 2) {
561 		printk(KERN_INFO "scsi scan: %d byte inquiry failed.  "
562 				"Consider BLIST_INQUIRY_36 for this device\n",
563 				try_inquiry_len);
564 
565 		/* If this pass failed, the third pass goes back and transfers
566 		 * the same amount as we successfully got in the first pass. */
567 		try_inquiry_len = first_inquiry_len;
568 		pass = 3;
569 		goto next_pass;
570 	}
571 
572 	/* If the last transfer attempt got an error, assume the
573 	 * peripheral doesn't exist or is dead. */
574 	if (result)
575 		return -EIO;
576 
577 	/* Don't report any more data than the device says is valid */
578 	sdev->inquiry_len = min(try_inquiry_len, response_len);
579 
580 	/*
581 	 * XXX Abort if the response length is less than 36? If less than
582 	 * 32, the lookup of the device flags (above) could be invalid,
583 	 * and it would be possible to take an incorrect action - we do
584 	 * not want to hang because of a short INQUIRY. On the flip side,
585 	 * if the device is spun down or becoming ready (and so it gives a
586 	 * short INQUIRY), an abort here prevents any further use of the
587 	 * device, including spin up.
588 	 *
589 	 * Related to the above issue:
590 	 *
591 	 * XXX Devices (disk or all?) should be sent a TEST UNIT READY,
592 	 * and if not ready, sent a START_STOP to start (maybe spin up) and
593 	 * then send the INQUIRY again, since the INQUIRY can change after
594 	 * a device is initialized.
595 	 *
596 	 * Ideally, start a device if explicitly asked to do so.  This
597 	 * assumes that a device is spun up on power on, spun down on
598 	 * request, and then spun up on request.
599 	 */
600 
601 	/*
602 	 * The scanning code needs to know the scsi_level, even if no
603 	 * device is attached at LUN 0 (SCSI_SCAN_TARGET_PRESENT) so
604 	 * non-zero LUNs can be scanned.
605 	 */
606 	sdev->scsi_level = inq_result[2] & 0x07;
607 	if (sdev->scsi_level >= 2 ||
608 	    (sdev->scsi_level == 1 && (inq_result[3] & 0x0f) == 1))
609 		sdev->scsi_level++;
610 	sdev->sdev_target->scsi_level = sdev->scsi_level;
611 
612 	return 0;
613 }
614 
615 /**
616  * scsi_add_lun - allocate and fully initialze a scsi_device
617  * @sdevscan:	holds information to be stored in the new scsi_device
618  * @sdevnew:	store the address of the newly allocated scsi_device
619  * @inq_result:	holds the result of a previous INQUIRY to the LUN
620  * @bflags:	black/white list flag
621  *
622  * Description:
623  *     Allocate and initialize a scsi_device matching sdevscan. Optionally
624  *     set fields based on values in *@bflags. If @sdevnew is not
625  *     NULL, store the address of the new scsi_device in *@sdevnew (needed
626  *     when scanning a particular LUN).
627  *
628  * Return:
629  *     SCSI_SCAN_NO_RESPONSE: could not allocate or setup a scsi_device
630  *     SCSI_SCAN_LUN_PRESENT: a new scsi_device was allocated and initialized
631  **/
632 static int scsi_add_lun(struct scsi_device *sdev, char *inq_result, int *bflags)
633 {
634 	/*
635 	 * XXX do not save the inquiry, since it can change underneath us,
636 	 * save just vendor/model/rev.
637 	 *
638 	 * Rather than save it and have an ioctl that retrieves the saved
639 	 * value, have an ioctl that executes the same INQUIRY code used
640 	 * in scsi_probe_lun, let user level programs doing INQUIRY
641 	 * scanning run at their own risk, or supply a user level program
642 	 * that can correctly scan.
643 	 */
644 	sdev->inquiry = kmalloc(sdev->inquiry_len, GFP_ATOMIC);
645 	if (sdev->inquiry == NULL) {
646 		return SCSI_SCAN_NO_RESPONSE;
647 	}
648 
649 	memcpy(sdev->inquiry, inq_result, sdev->inquiry_len);
650 	sdev->vendor = (char *) (sdev->inquiry + 8);
651 	sdev->model = (char *) (sdev->inquiry + 16);
652 	sdev->rev = (char *) (sdev->inquiry + 32);
653 
654 	if (*bflags & BLIST_ISROM) {
655 		/*
656 		 * It would be better to modify sdev->type, and set
657 		 * sdev->removable, but then the print_inquiry() output
658 		 * would not show TYPE_ROM; if print_inquiry() is removed
659 		 * the issue goes away.
660 		 */
661 		inq_result[0] = TYPE_ROM;
662 		inq_result[1] |= 0x80;	/* removable */
663 	} else if (*bflags & BLIST_NO_ULD_ATTACH)
664 		sdev->no_uld_attach = 1;
665 
666 	switch (sdev->type = (inq_result[0] & 0x1f)) {
667 	case TYPE_TAPE:
668 	case TYPE_DISK:
669 	case TYPE_PRINTER:
670 	case TYPE_MOD:
671 	case TYPE_PROCESSOR:
672 	case TYPE_SCANNER:
673 	case TYPE_MEDIUM_CHANGER:
674 	case TYPE_ENCLOSURE:
675 	case TYPE_COMM:
676 	case TYPE_RAID:
677 	case TYPE_RBC:
678 		sdev->writeable = 1;
679 		break;
680 	case TYPE_WORM:
681 	case TYPE_ROM:
682 		sdev->writeable = 0;
683 		break;
684 	default:
685 		printk(KERN_INFO "scsi: unknown device type %d\n", sdev->type);
686 	}
687 
688 	print_inquiry(inq_result);
689 
690 	/*
691 	 * For a peripheral qualifier (PQ) value of 1 (001b), the SCSI
692 	 * spec says: The device server is capable of supporting the
693 	 * specified peripheral device type on this logical unit. However,
694 	 * the physical device is not currently connected to this logical
695 	 * unit.
696 	 *
697 	 * The above is vague, as it implies that we could treat 001 and
698 	 * 011 the same. Stay compatible with previous code, and create a
699 	 * scsi_device for a PQ of 1
700 	 *
701 	 * Don't set the device offline here; rather let the upper
702 	 * level drivers eval the PQ to decide whether they should
703 	 * attach. So remove ((inq_result[0] >> 5) & 7) == 1 check.
704 	 */
705 
706 	sdev->inq_periph_qual = (inq_result[0] >> 5) & 7;
707 	sdev->removable = (0x80 & inq_result[1]) >> 7;
708 	sdev->lockable = sdev->removable;
709 	sdev->soft_reset = (inq_result[7] & 1) && ((inq_result[3] & 7) == 2);
710 
711 	if (sdev->scsi_level >= SCSI_3 || (sdev->inquiry_len > 56 &&
712 		inq_result[56] & 0x04))
713 		sdev->ppr = 1;
714 	if (inq_result[7] & 0x60)
715 		sdev->wdtr = 1;
716 	if (inq_result[7] & 0x10)
717 		sdev->sdtr = 1;
718 
719 	/*
720 	 * End sysfs code.
721 	 */
722 
723 	if ((sdev->scsi_level >= SCSI_2) && (inq_result[7] & 2) &&
724 	    !(*bflags & BLIST_NOTQ))
725 		sdev->tagged_supported = 1;
726 	/*
727 	 * Some devices (Texel CD ROM drives) have handshaking problems
728 	 * when used with the Seagate controllers. borken is initialized
729 	 * to 1, and then set it to 0 here.
730 	 */
731 	if ((*bflags & BLIST_BORKEN) == 0)
732 		sdev->borken = 0;
733 
734 	/*
735 	 * Apparently some really broken devices (contrary to the SCSI
736 	 * standards) need to be selected without asserting ATN
737 	 */
738 	if (*bflags & BLIST_SELECT_NO_ATN)
739 		sdev->select_no_atn = 1;
740 
741 	/*
742 	 * Maximum 512 sector transfer length
743 	 * broken RA4x00 Compaq Disk Array
744 	 */
745 	if (*bflags & BLIST_MAX_512)
746 		blk_queue_max_sectors(sdev->request_queue, 512);
747 
748 	/*
749 	 * Some devices may not want to have a start command automatically
750 	 * issued when a device is added.
751 	 */
752 	if (*bflags & BLIST_NOSTARTONADD)
753 		sdev->no_start_on_add = 1;
754 
755 	if (*bflags & BLIST_SINGLELUN)
756 		sdev->single_lun = 1;
757 
758 
759 	sdev->use_10_for_rw = 1;
760 
761 	if (*bflags & BLIST_MS_SKIP_PAGE_08)
762 		sdev->skip_ms_page_8 = 1;
763 
764 	if (*bflags & BLIST_MS_SKIP_PAGE_3F)
765 		sdev->skip_ms_page_3f = 1;
766 
767 	if (*bflags & BLIST_USE_10_BYTE_MS)
768 		sdev->use_10_for_ms = 1;
769 
770 	/* set the device running here so that slave configure
771 	 * may do I/O */
772 	scsi_device_set_state(sdev, SDEV_RUNNING);
773 
774 	if (*bflags & BLIST_MS_192_BYTES_FOR_3F)
775 		sdev->use_192_bytes_for_3f = 1;
776 
777 	if (*bflags & BLIST_NOT_LOCKABLE)
778 		sdev->lockable = 0;
779 
780 	if (*bflags & BLIST_RETRY_HWERROR)
781 		sdev->retry_hwerror = 1;
782 
783 	transport_configure_device(&sdev->sdev_gendev);
784 
785 	if (sdev->host->hostt->slave_configure) {
786 		int ret = sdev->host->hostt->slave_configure(sdev);
787 		if (ret) {
788 			/*
789 			 * if LLDD reports slave not present, don't clutter
790 			 * console with alloc failure messages
791 			 */
792 			if (ret != -ENXIO) {
793 				sdev_printk(KERN_ERR, sdev,
794 					"failed to configure device\n");
795 			}
796 			return SCSI_SCAN_NO_RESPONSE;
797 		}
798 	}
799 
800 	/*
801 	 * Ok, the device is now all set up, we can
802 	 * register it and tell the rest of the kernel
803 	 * about it.
804 	 */
805 	if (scsi_sysfs_add_sdev(sdev) != 0)
806 		return SCSI_SCAN_NO_RESPONSE;
807 
808 	return SCSI_SCAN_LUN_PRESENT;
809 }
810 
811 static inline void scsi_destroy_sdev(struct scsi_device *sdev)
812 {
813 	if (sdev->host->hostt->slave_destroy)
814 		sdev->host->hostt->slave_destroy(sdev);
815 	transport_destroy_device(&sdev->sdev_gendev);
816 	put_device(&sdev->sdev_gendev);
817 }
818 
819 
820 /**
821  * scsi_probe_and_add_lun - probe a LUN, if a LUN is found add it
822  * @starget:	pointer to target device structure
823  * @lun:	LUN of target device
824  * @sdevscan:	probe the LUN corresponding to this scsi_device
825  * @sdevnew:	store the value of any new scsi_device allocated
826  * @bflagsp:	store bflags here if not NULL
827  *
828  * Description:
829  *     Call scsi_probe_lun, if a LUN with an attached device is found,
830  *     allocate and set it up by calling scsi_add_lun.
831  *
832  * Return:
833  *     SCSI_SCAN_NO_RESPONSE: could not allocate or setup a scsi_device
834  *     SCSI_SCAN_TARGET_PRESENT: target responded, but no device is
835  *         attached at the LUN
836  *     SCSI_SCAN_LUN_PRESENT: a new scsi_device was allocated and initialized
837  **/
838 static int scsi_probe_and_add_lun(struct scsi_target *starget,
839 				  uint lun, int *bflagsp,
840 				  struct scsi_device **sdevp, int rescan,
841 				  void *hostdata)
842 {
843 	struct scsi_device *sdev;
844 	unsigned char *result;
845 	int bflags, res = SCSI_SCAN_NO_RESPONSE, result_len = 256;
846 	struct Scsi_Host *shost = dev_to_shost(starget->dev.parent);
847 
848 	/*
849 	 * The rescan flag is used as an optimization, the first scan of a
850 	 * host adapter calls into here with rescan == 0.
851 	 */
852 	sdev = scsi_device_lookup_by_target(starget, lun);
853 	if (sdev) {
854 		if (rescan || sdev->sdev_state != SDEV_CREATED) {
855 			SCSI_LOG_SCAN_BUS(3, printk(KERN_INFO
856 				"scsi scan: device exists on %s\n",
857 				sdev->sdev_gendev.bus_id));
858 			if (sdevp)
859 				*sdevp = sdev;
860 			else
861 				scsi_device_put(sdev);
862 
863 			if (bflagsp)
864 				*bflagsp = scsi_get_device_flags(sdev,
865 								 sdev->vendor,
866 								 sdev->model);
867 			return SCSI_SCAN_LUN_PRESENT;
868 		}
869 		scsi_device_put(sdev);
870 	} else
871 		sdev = scsi_alloc_sdev(starget, lun, hostdata);
872 	if (!sdev)
873 		goto out;
874 
875 	result = kmalloc(result_len, GFP_ATOMIC |
876 			((shost->unchecked_isa_dma) ? __GFP_DMA : 0));
877 	if (!result)
878 		goto out_free_sdev;
879 
880 	if (scsi_probe_lun(sdev, result, result_len, &bflags))
881 		goto out_free_result;
882 
883 	/*
884 	 * result contains valid SCSI INQUIRY data.
885 	 */
886 	if ((result[0] >> 5) == 3) {
887 		/*
888 		 * For a Peripheral qualifier 3 (011b), the SCSI
889 		 * spec says: The device server is not capable of
890 		 * supporting a physical device on this logical
891 		 * unit.
892 		 *
893 		 * For disks, this implies that there is no
894 		 * logical disk configured at sdev->lun, but there
895 		 * is a target id responding.
896 		 */
897 		SCSI_LOG_SCAN_BUS(3, printk(KERN_INFO
898 					"scsi scan: peripheral qualifier of 3,"
899 					" no device added\n"));
900 		res = SCSI_SCAN_TARGET_PRESENT;
901 		goto out_free_result;
902 	}
903 
904 	/*
905 	 * Non-standard SCSI targets may set the PDT to 0x1f (unknown or
906 	 * no device type) instead of using the Peripheral Qualifier to
907 	 * indicate that no LUN is present.  For example, USB UFI does this.
908 	 */
909 	if (starget->pdt_1f_for_no_lun && (result[0] & 0x1f) == 0x1f) {
910 		SCSI_LOG_SCAN_BUS(3, printk(KERN_INFO
911 					"scsi scan: peripheral device type"
912 					" of 31, no device added\n"));
913 		res = SCSI_SCAN_TARGET_PRESENT;
914 		goto out_free_result;
915 	}
916 
917 	res = scsi_add_lun(sdev, result, &bflags);
918 	if (res == SCSI_SCAN_LUN_PRESENT) {
919 		if (bflags & BLIST_KEY) {
920 			sdev->lockable = 0;
921 			scsi_unlock_floptical(sdev, result);
922 		}
923 		if (bflagsp)
924 			*bflagsp = bflags;
925 	}
926 
927  out_free_result:
928 	kfree(result);
929  out_free_sdev:
930 	if (res == SCSI_SCAN_LUN_PRESENT) {
931 		if (sdevp) {
932 			if (scsi_device_get(sdev) == 0) {
933 				*sdevp = sdev;
934 			} else {
935 				__scsi_remove_device(sdev);
936 				res = SCSI_SCAN_NO_RESPONSE;
937 			}
938 		}
939 	} else
940 		scsi_destroy_sdev(sdev);
941  out:
942 	return res;
943 }
944 
945 /**
946  * scsi_sequential_lun_scan - sequentially scan a SCSI target
947  * @starget:	pointer to target structure to scan
948  * @bflags:	black/white list flag for LUN 0
949  * @lun0_res:	result of scanning LUN 0
950  *
951  * Description:
952  *     Generally, scan from LUN 1 (LUN 0 is assumed to already have been
953  *     scanned) to some maximum lun until a LUN is found with no device
954  *     attached. Use the bflags to figure out any oddities.
955  *
956  *     Modifies sdevscan->lun.
957  **/
958 static void scsi_sequential_lun_scan(struct scsi_target *starget,
959 				     int bflags, int lun0_res, int scsi_level,
960 				     int rescan)
961 {
962 	unsigned int sparse_lun, lun, max_dev_lun;
963 	struct Scsi_Host *shost = dev_to_shost(starget->dev.parent);
964 
965 	SCSI_LOG_SCAN_BUS(3, printk(KERN_INFO "scsi scan: Sequential scan of"
966 				    "%s\n", starget->dev.bus_id));
967 
968 	max_dev_lun = min(max_scsi_luns, shost->max_lun);
969 	/*
970 	 * If this device is known to support sparse multiple units,
971 	 * override the other settings, and scan all of them. Normally,
972 	 * SCSI-3 devices should be scanned via the REPORT LUNS.
973 	 */
974 	if (bflags & BLIST_SPARSELUN) {
975 		max_dev_lun = shost->max_lun;
976 		sparse_lun = 1;
977 	} else
978 		sparse_lun = 0;
979 
980 	/*
981 	 * If not sparse lun and no device attached at LUN 0 do not scan
982 	 * any further.
983 	 */
984 	if (!sparse_lun && (lun0_res != SCSI_SCAN_LUN_PRESENT))
985 		return;
986 
987 	/*
988 	 * If less than SCSI_1_CSS, and no special lun scaning, stop
989 	 * scanning; this matches 2.4 behaviour, but could just be a bug
990 	 * (to continue scanning a SCSI_1_CSS device).
991 	 *
992 	 * This test is broken.  We might not have any device on lun0 for
993 	 * a sparselun device, and if that's the case then how would we
994 	 * know the real scsi_level, eh?  It might make sense to just not
995 	 * scan any SCSI_1 device for non-0 luns, but that check would best
996 	 * go into scsi_alloc_sdev() and just have it return null when asked
997 	 * to alloc an sdev for lun > 0 on an already found SCSI_1 device.
998 	 *
999 	if ((sdevscan->scsi_level < SCSI_1_CCS) &&
1000 	    ((bflags & (BLIST_FORCELUN | BLIST_SPARSELUN | BLIST_MAX5LUN))
1001 	     == 0))
1002 		return;
1003 	 */
1004 	/*
1005 	 * If this device is known to support multiple units, override
1006 	 * the other settings, and scan all of them.
1007 	 */
1008 	if (bflags & BLIST_FORCELUN)
1009 		max_dev_lun = shost->max_lun;
1010 	/*
1011 	 * REGAL CDC-4X: avoid hang after LUN 4
1012 	 */
1013 	if (bflags & BLIST_MAX5LUN)
1014 		max_dev_lun = min(5U, max_dev_lun);
1015 	/*
1016 	 * Do not scan SCSI-2 or lower device past LUN 7, unless
1017 	 * BLIST_LARGELUN.
1018 	 */
1019 	if (scsi_level < SCSI_3 && !(bflags & BLIST_LARGELUN))
1020 		max_dev_lun = min(8U, max_dev_lun);
1021 
1022 	/*
1023 	 * We have already scanned LUN 0, so start at LUN 1. Keep scanning
1024 	 * until we reach the max, or no LUN is found and we are not
1025 	 * sparse_lun.
1026 	 */
1027 	for (lun = 1; lun < max_dev_lun; ++lun)
1028 		if ((scsi_probe_and_add_lun(starget, lun, NULL, NULL, rescan,
1029 					    NULL) != SCSI_SCAN_LUN_PRESENT) &&
1030 		    !sparse_lun)
1031 			return;
1032 }
1033 
1034 /**
1035  * scsilun_to_int: convert a scsi_lun to an int
1036  * @scsilun:	struct scsi_lun to be converted.
1037  *
1038  * Description:
1039  *     Convert @scsilun from a struct scsi_lun to a four byte host byte-ordered
1040  *     integer, and return the result. The caller must check for
1041  *     truncation before using this function.
1042  *
1043  * Notes:
1044  *     The struct scsi_lun is assumed to be four levels, with each level
1045  *     effectively containing a SCSI byte-ordered (big endian) short; the
1046  *     addressing bits of each level are ignored (the highest two bits).
1047  *     For a description of the LUN format, post SCSI-3 see the SCSI
1048  *     Architecture Model, for SCSI-3 see the SCSI Controller Commands.
1049  *
1050  *     Given a struct scsi_lun of: 0a 04 0b 03 00 00 00 00, this function returns
1051  *     the integer: 0x0b030a04
1052  **/
1053 static int scsilun_to_int(struct scsi_lun *scsilun)
1054 {
1055 	int i;
1056 	unsigned int lun;
1057 
1058 	lun = 0;
1059 	for (i = 0; i < sizeof(lun); i += 2)
1060 		lun = lun | (((scsilun->scsi_lun[i] << 8) |
1061 			      scsilun->scsi_lun[i + 1]) << (i * 8));
1062 	return lun;
1063 }
1064 
1065 /**
1066  * int_to_scsilun: reverts an int into a scsi_lun
1067  * @int:        integer to be reverted
1068  * @scsilun:	struct scsi_lun to be set.
1069  *
1070  * Description:
1071  *     Reverts the functionality of the scsilun_to_int, which packed
1072  *     an 8-byte lun value into an int. This routine unpacks the int
1073  *     back into the lun value.
1074  *     Note: the scsilun_to_int() routine does not truly handle all
1075  *     8bytes of the lun value. This functions restores only as much
1076  *     as was set by the routine.
1077  *
1078  * Notes:
1079  *     Given an integer : 0x0b030a04,  this function returns a
1080  *     scsi_lun of : struct scsi_lun of: 0a 04 0b 03 00 00 00 00
1081  *
1082  **/
1083 void int_to_scsilun(unsigned int lun, struct scsi_lun *scsilun)
1084 {
1085 	int i;
1086 
1087 	memset(scsilun->scsi_lun, 0, sizeof(scsilun->scsi_lun));
1088 
1089 	for (i = 0; i < sizeof(lun); i += 2) {
1090 		scsilun->scsi_lun[i] = (lun >> 8) & 0xFF;
1091 		scsilun->scsi_lun[i+1] = lun & 0xFF;
1092 		lun = lun >> 16;
1093 	}
1094 }
1095 EXPORT_SYMBOL(int_to_scsilun);
1096 
1097 /**
1098  * scsi_report_lun_scan - Scan using SCSI REPORT LUN results
1099  * @sdevscan:	scan the host, channel, and id of this scsi_device
1100  *
1101  * Description:
1102  *     If @sdevscan is for a SCSI-3 or up device, send a REPORT LUN
1103  *     command, and scan the resulting list of LUNs by calling
1104  *     scsi_probe_and_add_lun.
1105  *
1106  *     Modifies sdevscan->lun.
1107  *
1108  * Return:
1109  *     0: scan completed (or no memory, so further scanning is futile)
1110  *     1: no report lun scan, or not configured
1111  **/
1112 static int scsi_report_lun_scan(struct scsi_target *starget, int bflags,
1113 				int rescan)
1114 {
1115 	char devname[64];
1116 	unsigned char scsi_cmd[MAX_COMMAND_SIZE];
1117 	unsigned int length;
1118 	unsigned int lun;
1119 	unsigned int num_luns;
1120 	unsigned int retries;
1121 	int result;
1122 	struct scsi_lun *lunp, *lun_data;
1123 	u8 *data;
1124 	struct scsi_sense_hdr sshdr;
1125 	struct scsi_device *sdev;
1126 	struct Scsi_Host *shost = dev_to_shost(&starget->dev);
1127 	int ret = 0;
1128 
1129 	/*
1130 	 * Only support SCSI-3 and up devices if BLIST_NOREPORTLUN is not set.
1131 	 * Also allow SCSI-2 if BLIST_REPORTLUN2 is set and host adapter does
1132 	 * support more than 8 LUNs.
1133 	 */
1134 	if (bflags & BLIST_NOREPORTLUN)
1135 		return 1;
1136 	if (starget->scsi_level < SCSI_2 &&
1137 	    starget->scsi_level != SCSI_UNKNOWN)
1138 		return 1;
1139 	if (starget->scsi_level < SCSI_3 &&
1140 	    (!(bflags & BLIST_REPORTLUN2) || shost->max_lun <= 8))
1141 		return 1;
1142 	if (bflags & BLIST_NOLUN)
1143 		return 0;
1144 
1145 	if (!(sdev = scsi_device_lookup_by_target(starget, 0))) {
1146 		sdev = scsi_alloc_sdev(starget, 0, NULL);
1147 		if (!sdev)
1148 			return 0;
1149 		if (scsi_device_get(sdev))
1150 			return 0;
1151 	}
1152 
1153 	sprintf(devname, "host %d channel %d id %d",
1154 		shost->host_no, sdev->channel, sdev->id);
1155 
1156 	/*
1157 	 * Allocate enough to hold the header (the same size as one scsi_lun)
1158 	 * plus the max number of luns we are requesting.
1159 	 *
1160 	 * Reallocating and trying again (with the exact amount we need)
1161 	 * would be nice, but then we need to somehow limit the size
1162 	 * allocated based on the available memory and the limits of
1163 	 * kmalloc - we don't want a kmalloc() failure of a huge value to
1164 	 * prevent us from finding any LUNs on this target.
1165 	 */
1166 	length = (max_scsi_report_luns + 1) * sizeof(struct scsi_lun);
1167 	lun_data = kmalloc(length, GFP_ATOMIC |
1168 			   (sdev->host->unchecked_isa_dma ? __GFP_DMA : 0));
1169 	if (!lun_data) {
1170 		printk(ALLOC_FAILURE_MSG, __FUNCTION__);
1171 		goto out;
1172 	}
1173 
1174 	scsi_cmd[0] = REPORT_LUNS;
1175 
1176 	/*
1177 	 * bytes 1 - 5: reserved, set to zero.
1178 	 */
1179 	memset(&scsi_cmd[1], 0, 5);
1180 
1181 	/*
1182 	 * bytes 6 - 9: length of the command.
1183 	 */
1184 	scsi_cmd[6] = (unsigned char) (length >> 24) & 0xff;
1185 	scsi_cmd[7] = (unsigned char) (length >> 16) & 0xff;
1186 	scsi_cmd[8] = (unsigned char) (length >> 8) & 0xff;
1187 	scsi_cmd[9] = (unsigned char) length & 0xff;
1188 
1189 	scsi_cmd[10] = 0;	/* reserved */
1190 	scsi_cmd[11] = 0;	/* control */
1191 
1192 	/*
1193 	 * We can get a UNIT ATTENTION, for example a power on/reset, so
1194 	 * retry a few times (like sd.c does for TEST UNIT READY).
1195 	 * Experience shows some combinations of adapter/devices get at
1196 	 * least two power on/resets.
1197 	 *
1198 	 * Illegal requests (for devices that do not support REPORT LUNS)
1199 	 * should come through as a check condition, and will not generate
1200 	 * a retry.
1201 	 */
1202 	for (retries = 0; retries < 3; retries++) {
1203 		SCSI_LOG_SCAN_BUS(3, printk (KERN_INFO "scsi scan: Sending"
1204 				" REPORT LUNS to %s (try %d)\n", devname,
1205 				retries));
1206 
1207 		result = scsi_execute_req(sdev, scsi_cmd, DMA_FROM_DEVICE,
1208 					  lun_data, length, &sshdr,
1209 					  SCSI_TIMEOUT + 4 * HZ, 3);
1210 
1211 		SCSI_LOG_SCAN_BUS(3, printk (KERN_INFO "scsi scan: REPORT LUNS"
1212 				" %s (try %d) result 0x%x\n", result
1213 				?  "failed" : "successful", retries, result));
1214 		if (result == 0)
1215 			break;
1216 		else if (scsi_sense_valid(&sshdr)) {
1217 			if (sshdr.sense_key != UNIT_ATTENTION)
1218 				break;
1219 		}
1220 	}
1221 
1222 	if (result) {
1223 		/*
1224 		 * The device probably does not support a REPORT LUN command
1225 		 */
1226 		ret = 1;
1227 		goto out_err;
1228 	}
1229 
1230 	/*
1231 	 * Get the length from the first four bytes of lun_data.
1232 	 */
1233 	data = (u8 *) lun_data->scsi_lun;
1234 	length = ((data[0] << 24) | (data[1] << 16) |
1235 		  (data[2] << 8) | (data[3] << 0));
1236 
1237 	num_luns = (length / sizeof(struct scsi_lun));
1238 	if (num_luns > max_scsi_report_luns) {
1239 		printk(KERN_WARNING "scsi: On %s only %d (max_scsi_report_luns)"
1240 		       " of %d luns reported, try increasing"
1241 		       " max_scsi_report_luns.\n", devname,
1242 		       max_scsi_report_luns, num_luns);
1243 		num_luns = max_scsi_report_luns;
1244 	}
1245 
1246 	SCSI_LOG_SCAN_BUS(3, sdev_printk (KERN_INFO, sdev,
1247 		"scsi scan: REPORT LUN scan\n"));
1248 
1249 	/*
1250 	 * Scan the luns in lun_data. The entry at offset 0 is really
1251 	 * the header, so start at 1 and go up to and including num_luns.
1252 	 */
1253 	for (lunp = &lun_data[1]; lunp <= &lun_data[num_luns]; lunp++) {
1254 		lun = scsilun_to_int(lunp);
1255 
1256 		/*
1257 		 * Check if the unused part of lunp is non-zero, and so
1258 		 * does not fit in lun.
1259 		 */
1260 		if (memcmp(&lunp->scsi_lun[sizeof(lun)], "\0\0\0\0", 4)) {
1261 			int i;
1262 
1263 			/*
1264 			 * Output an error displaying the LUN in byte order,
1265 			 * this differs from what linux would print for the
1266 			 * integer LUN value.
1267 			 */
1268 			printk(KERN_WARNING "scsi: %s lun 0x", devname);
1269 			data = (char *)lunp->scsi_lun;
1270 			for (i = 0; i < sizeof(struct scsi_lun); i++)
1271 				printk("%02x", data[i]);
1272 			printk(" has a LUN larger than currently supported.\n");
1273 		} else if (lun > sdev->host->max_lun) {
1274 			printk(KERN_WARNING "scsi: %s lun%d has a LUN larger"
1275 			       " than allowed by the host adapter\n",
1276 			       devname, lun);
1277 		} else {
1278 			int res;
1279 
1280 			res = scsi_probe_and_add_lun(starget,
1281 				lun, NULL, NULL, rescan, NULL);
1282 			if (res == SCSI_SCAN_NO_RESPONSE) {
1283 				/*
1284 				 * Got some results, but now none, abort.
1285 				 */
1286 				sdev_printk(KERN_ERR, sdev,
1287 					"Unexpected response"
1288 				        " from lun %d while scanning, scan"
1289 				        " aborted\n", lun);
1290 				break;
1291 			}
1292 		}
1293 	}
1294 
1295  out_err:
1296 	kfree(lun_data);
1297  out:
1298 	scsi_device_put(sdev);
1299 	if (sdev->sdev_state == SDEV_CREATED)
1300 		/*
1301 		 * the sdev we used didn't appear in the report luns scan
1302 		 */
1303 		scsi_destroy_sdev(sdev);
1304 	return ret;
1305 }
1306 
1307 struct scsi_device *__scsi_add_device(struct Scsi_Host *shost, uint channel,
1308 				      uint id, uint lun, void *hostdata)
1309 {
1310 	struct scsi_device *sdev = ERR_PTR(-ENODEV);
1311 	struct device *parent = &shost->shost_gendev;
1312 	struct scsi_target *starget;
1313 
1314 	starget = scsi_alloc_target(parent, channel, id);
1315 	if (!starget)
1316 		return ERR_PTR(-ENOMEM);
1317 
1318 	get_device(&starget->dev);
1319 	mutex_lock(&shost->scan_mutex);
1320 	if (scsi_host_scan_allowed(shost))
1321 		scsi_probe_and_add_lun(starget, lun, NULL, &sdev, 1, hostdata);
1322 	mutex_unlock(&shost->scan_mutex);
1323 	scsi_target_reap(starget);
1324 	put_device(&starget->dev);
1325 
1326 	return sdev;
1327 }
1328 EXPORT_SYMBOL(__scsi_add_device);
1329 
1330 int scsi_add_device(struct Scsi_Host *host, uint channel,
1331 		    uint target, uint lun)
1332 {
1333 	struct scsi_device *sdev =
1334 		__scsi_add_device(host, channel, target, lun, NULL);
1335 	if (IS_ERR(sdev))
1336 		return PTR_ERR(sdev);
1337 
1338 	scsi_device_put(sdev);
1339 	return 0;
1340 }
1341 EXPORT_SYMBOL(scsi_add_device);
1342 
1343 void scsi_rescan_device(struct device *dev)
1344 {
1345 	struct scsi_driver *drv;
1346 
1347 	if (!dev->driver)
1348 		return;
1349 
1350 	drv = to_scsi_driver(dev->driver);
1351 	if (try_module_get(drv->owner)) {
1352 		if (drv->rescan)
1353 			drv->rescan(dev);
1354 		module_put(drv->owner);
1355 	}
1356 }
1357 EXPORT_SYMBOL(scsi_rescan_device);
1358 
1359 static void __scsi_scan_target(struct device *parent, unsigned int channel,
1360 		unsigned int id, unsigned int lun, int rescan)
1361 {
1362 	struct Scsi_Host *shost = dev_to_shost(parent);
1363 	int bflags = 0;
1364 	int res;
1365 	struct scsi_target *starget;
1366 
1367 	if (shost->this_id == id)
1368 		/*
1369 		 * Don't scan the host adapter
1370 		 */
1371 		return;
1372 
1373 	starget = scsi_alloc_target(parent, channel, id);
1374 	if (!starget)
1375 		return;
1376 
1377 	get_device(&starget->dev);
1378 	if (lun != SCAN_WILD_CARD) {
1379 		/*
1380 		 * Scan for a specific host/chan/id/lun.
1381 		 */
1382 		scsi_probe_and_add_lun(starget, lun, NULL, NULL, rescan, NULL);
1383 		goto out_reap;
1384 	}
1385 
1386 	/*
1387 	 * Scan LUN 0, if there is some response, scan further. Ideally, we
1388 	 * would not configure LUN 0 until all LUNs are scanned.
1389 	 */
1390 	res = scsi_probe_and_add_lun(starget, 0, &bflags, NULL, rescan, NULL);
1391 	if (res == SCSI_SCAN_LUN_PRESENT || res == SCSI_SCAN_TARGET_PRESENT) {
1392 		if (scsi_report_lun_scan(starget, bflags, rescan) != 0)
1393 			/*
1394 			 * The REPORT LUN did not scan the target,
1395 			 * do a sequential scan.
1396 			 */
1397 			scsi_sequential_lun_scan(starget, bflags,
1398 				       	res, starget->scsi_level, rescan);
1399 	}
1400 
1401  out_reap:
1402 	/* now determine if the target has any children at all
1403 	 * and if not, nuke it */
1404 	scsi_target_reap(starget);
1405 
1406 	put_device(&starget->dev);
1407 }
1408 
1409 /**
1410  * scsi_scan_target - scan a target id, possibly including all LUNs on the
1411  *     target.
1412  * @parent:	host to scan
1413  * @channel:	channel to scan
1414  * @id:		target id to scan
1415  * @lun:	Specific LUN to scan or SCAN_WILD_CARD
1416  * @rescan:	passed to LUN scanning routines
1417  *
1418  * Description:
1419  *     Scan the target id on @parent, @channel, and @id. Scan at least LUN 0,
1420  *     and possibly all LUNs on the target id.
1421  *
1422  *     First try a REPORT LUN scan, if that does not scan the target, do a
1423  *     sequential scan of LUNs on the target id.
1424  **/
1425 void scsi_scan_target(struct device *parent, unsigned int channel,
1426 		      unsigned int id, unsigned int lun, int rescan)
1427 {
1428 	struct Scsi_Host *shost = dev_to_shost(parent);
1429 
1430 	mutex_lock(&shost->scan_mutex);
1431 	if (scsi_host_scan_allowed(shost))
1432 		__scsi_scan_target(parent, channel, id, lun, rescan);
1433 	mutex_unlock(&shost->scan_mutex);
1434 }
1435 EXPORT_SYMBOL(scsi_scan_target);
1436 
1437 static void scsi_scan_channel(struct Scsi_Host *shost, unsigned int channel,
1438 			      unsigned int id, unsigned int lun, int rescan)
1439 {
1440 	uint order_id;
1441 
1442 	if (id == SCAN_WILD_CARD)
1443 		for (id = 0; id < shost->max_id; ++id) {
1444 			/*
1445 			 * XXX adapter drivers when possible (FCP, iSCSI)
1446 			 * could modify max_id to match the current max,
1447 			 * not the absolute max.
1448 			 *
1449 			 * XXX add a shost id iterator, so for example,
1450 			 * the FC ID can be the same as a target id
1451 			 * without a huge overhead of sparse id's.
1452 			 */
1453 			if (shost->reverse_ordering)
1454 				/*
1455 				 * Scan from high to low id.
1456 				 */
1457 				order_id = shost->max_id - id - 1;
1458 			else
1459 				order_id = id;
1460 			__scsi_scan_target(&shost->shost_gendev, channel,
1461 					order_id, lun, rescan);
1462 		}
1463 	else
1464 		__scsi_scan_target(&shost->shost_gendev, channel,
1465 				id, lun, rescan);
1466 }
1467 
1468 int scsi_scan_host_selected(struct Scsi_Host *shost, unsigned int channel,
1469 			    unsigned int id, unsigned int lun, int rescan)
1470 {
1471 	SCSI_LOG_SCAN_BUS(3, shost_printk (KERN_INFO, shost,
1472 		"%s: <%u:%u:%u>\n",
1473 		__FUNCTION__, channel, id, lun));
1474 
1475 	if (((channel != SCAN_WILD_CARD) && (channel > shost->max_channel)) ||
1476 	    ((id != SCAN_WILD_CARD) && (id > shost->max_id)) ||
1477 	    ((lun != SCAN_WILD_CARD) && (lun > shost->max_lun)))
1478 		return -EINVAL;
1479 
1480 	mutex_lock(&shost->scan_mutex);
1481 	if (scsi_host_scan_allowed(shost)) {
1482 		if (channel == SCAN_WILD_CARD)
1483 			for (channel = 0; channel <= shost->max_channel;
1484 			     channel++)
1485 				scsi_scan_channel(shost, channel, id, lun,
1486 						  rescan);
1487 		else
1488 			scsi_scan_channel(shost, channel, id, lun, rescan);
1489 	}
1490 	mutex_unlock(&shost->scan_mutex);
1491 
1492 	return 0;
1493 }
1494 
1495 /**
1496  * scsi_scan_host - scan the given adapter
1497  * @shost:	adapter to scan
1498  **/
1499 void scsi_scan_host(struct Scsi_Host *shost)
1500 {
1501 	scsi_scan_host_selected(shost, SCAN_WILD_CARD, SCAN_WILD_CARD,
1502 				SCAN_WILD_CARD, 0);
1503 }
1504 EXPORT_SYMBOL(scsi_scan_host);
1505 
1506 void scsi_forget_host(struct Scsi_Host *shost)
1507 {
1508 	struct scsi_device *sdev;
1509 	unsigned long flags;
1510 
1511  restart:
1512 	spin_lock_irqsave(shost->host_lock, flags);
1513 	list_for_each_entry(sdev, &shost->__devices, siblings) {
1514 		if (sdev->sdev_state == SDEV_DEL)
1515 			continue;
1516 		spin_unlock_irqrestore(shost->host_lock, flags);
1517 		__scsi_remove_device(sdev);
1518 		goto restart;
1519 	}
1520 	spin_unlock_irqrestore(shost->host_lock, flags);
1521 }
1522 
1523 /*
1524  * Function:    scsi_get_host_dev()
1525  *
1526  * Purpose:     Create a scsi_device that points to the host adapter itself.
1527  *
1528  * Arguments:   SHpnt   - Host that needs a scsi_device
1529  *
1530  * Lock status: None assumed.
1531  *
1532  * Returns:     The scsi_device or NULL
1533  *
1534  * Notes:
1535  *	Attach a single scsi_device to the Scsi_Host - this should
1536  *	be made to look like a "pseudo-device" that points to the
1537  *	HA itself.
1538  *
1539  *	Note - this device is not accessible from any high-level
1540  *	drivers (including generics), which is probably not
1541  *	optimal.  We can add hooks later to attach
1542  */
1543 struct scsi_device *scsi_get_host_dev(struct Scsi_Host *shost)
1544 {
1545 	struct scsi_device *sdev = NULL;
1546 	struct scsi_target *starget;
1547 
1548 	mutex_lock(&shost->scan_mutex);
1549 	if (!scsi_host_scan_allowed(shost))
1550 		goto out;
1551 	starget = scsi_alloc_target(&shost->shost_gendev, 0, shost->this_id);
1552 	if (!starget)
1553 		goto out;
1554 
1555 	sdev = scsi_alloc_sdev(starget, 0, NULL);
1556 	if (sdev) {
1557 		sdev->sdev_gendev.parent = get_device(&starget->dev);
1558 		sdev->borken = 0;
1559 	}
1560 	put_device(&starget->dev);
1561  out:
1562 	mutex_unlock(&shost->scan_mutex);
1563 	return sdev;
1564 }
1565 EXPORT_SYMBOL(scsi_get_host_dev);
1566 
1567 /*
1568  * Function:    scsi_free_host_dev()
1569  *
1570  * Purpose:     Free a scsi_device that points to the host adapter itself.
1571  *
1572  * Arguments:   SHpnt   - Host that needs a scsi_device
1573  *
1574  * Lock status: None assumed.
1575  *
1576  * Returns:     Nothing
1577  *
1578  * Notes:
1579  */
1580 void scsi_free_host_dev(struct scsi_device *sdev)
1581 {
1582 	BUG_ON(sdev->id != sdev->host->this_id);
1583 
1584 	scsi_destroy_sdev(sdev);
1585 }
1586 EXPORT_SYMBOL(scsi_free_host_dev);
1587 
1588