xref: /linux/drivers/scsi/scsi_scan.c (revision 36ca1195ad7f760a6af3814cb002bd3a3d4b4db1)
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  * @sreq:	used to send the command
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 using
119  *     @sreq to unlock a device, storing the (unused) results into result.
120  *     Called for BLIST_KEY devices.
121  **/
122 static void scsi_unlock_floptical(struct scsi_request *sreq,
123 				  unsigned char *result)
124 {
125 	unsigned char scsi_cmd[MAX_COMMAND_SIZE];
126 
127 	printk(KERN_NOTICE "scsi: unlocking floptical drive\n");
128 	scsi_cmd[0] = MODE_SENSE;
129 	scsi_cmd[1] = 0;
130 	scsi_cmd[2] = 0x2e;
131 	scsi_cmd[3] = 0;
132 	scsi_cmd[4] = 0x2a;	/* size */
133 	scsi_cmd[5] = 0;
134 	sreq->sr_cmd_len = 0;
135 	sreq->sr_data_direction = DMA_FROM_DEVICE;
136 	scsi_wait_req(sreq, scsi_cmd, result, 0x2a /* size */, SCSI_TIMEOUT, 3);
137 }
138 
139 /**
140  * print_inquiry - printk the inquiry information
141  * @inq_result:	printk this SCSI INQUIRY
142  *
143  * Description:
144  *     printk the vendor, model, and other information found in the
145  *     INQUIRY data in @inq_result.
146  *
147  * Notes:
148  *     Remove this, and replace with a hotplug event that logs any
149  *     relevant information.
150  **/
151 static void print_inquiry(unsigned char *inq_result)
152 {
153 	int i;
154 
155 	printk(KERN_NOTICE "  Vendor: ");
156 	for (i = 8; i < 16; i++)
157 		if (inq_result[i] >= 0x20 && i < inq_result[4] + 5)
158 			printk("%c", inq_result[i]);
159 		else
160 			printk(" ");
161 
162 	printk("  Model: ");
163 	for (i = 16; i < 32; i++)
164 		if (inq_result[i] >= 0x20 && i < inq_result[4] + 5)
165 			printk("%c", inq_result[i]);
166 		else
167 			printk(" ");
168 
169 	printk("  Rev: ");
170 	for (i = 32; i < 36; i++)
171 		if (inq_result[i] >= 0x20 && i < inq_result[4] + 5)
172 			printk("%c", inq_result[i]);
173 		else
174 			printk(" ");
175 
176 	printk("\n");
177 
178 	i = inq_result[0] & 0x1f;
179 
180 	printk(KERN_NOTICE "  Type:   %s ",
181 	       i <
182 	       MAX_SCSI_DEVICE_CODE ? scsi_device_types[i] :
183 	       "Unknown          ");
184 	printk("                 ANSI SCSI revision: %02x",
185 	       inq_result[2] & 0x07);
186 	if ((inq_result[2] & 0x07) == 1 && (inq_result[3] & 0x0f) == 1)
187 		printk(" CCS\n");
188 	else
189 		printk("\n");
190 }
191 
192 /**
193  * scsi_alloc_sdev - allocate and setup a scsi_Device
194  *
195  * Description:
196  *     Allocate, initialize for io, and return a pointer to a scsi_Device.
197  *     Stores the @shost, @channel, @id, and @lun in the scsi_Device, and
198  *     adds scsi_Device to the appropriate list.
199  *
200  * Return value:
201  *     scsi_Device pointer, or NULL on failure.
202  **/
203 static struct scsi_device *scsi_alloc_sdev(struct scsi_target *starget,
204 					   unsigned int lun, void *hostdata)
205 {
206 	struct scsi_device *sdev;
207 	int display_failure_msg = 1, ret;
208 	struct Scsi_Host *shost = dev_to_shost(starget->dev.parent);
209 
210 	sdev = kmalloc(sizeof(*sdev) + shost->transportt->device_size,
211 		       GFP_ATOMIC);
212 	if (!sdev)
213 		goto out;
214 
215 	memset(sdev, 0, sizeof(*sdev));
216 	sdev->vendor = scsi_null_device_strs;
217 	sdev->model = scsi_null_device_strs;
218 	sdev->rev = scsi_null_device_strs;
219 	sdev->host = shost;
220 	sdev->id = starget->id;
221 	sdev->lun = lun;
222 	sdev->channel = starget->channel;
223 	sdev->sdev_state = SDEV_CREATED;
224 	INIT_LIST_HEAD(&sdev->siblings);
225 	INIT_LIST_HEAD(&sdev->same_target_siblings);
226 	INIT_LIST_HEAD(&sdev->cmd_list);
227 	INIT_LIST_HEAD(&sdev->starved_entry);
228 	spin_lock_init(&sdev->list_lock);
229 
230 	sdev->sdev_gendev.parent = get_device(&starget->dev);
231 	sdev->sdev_target = starget;
232 
233 	/* usually NULL and set by ->slave_alloc instead */
234 	sdev->hostdata = hostdata;
235 
236 	/* if the device needs this changing, it may do so in the
237 	 * slave_configure function */
238 	sdev->max_device_blocked = SCSI_DEFAULT_DEVICE_BLOCKED;
239 
240 	/*
241 	 * Some low level driver could use device->type
242 	 */
243 	sdev->type = -1;
244 
245 	/*
246 	 * Assume that the device will have handshaking problems,
247 	 * and then fix this field later if it turns out it
248 	 * doesn't
249 	 */
250 	sdev->borken = 1;
251 
252 	sdev->request_queue = scsi_alloc_queue(sdev);
253 	if (!sdev->request_queue) {
254 		/* release fn is set up in scsi_sysfs_device_initialise, so
255 		 * have to free and put manually here */
256 		put_device(&starget->dev);
257 		goto out;
258 	}
259 
260 	sdev->request_queue->queuedata = sdev;
261 	scsi_adjust_queue_depth(sdev, 0, sdev->host->cmd_per_lun);
262 
263 	scsi_sysfs_device_initialize(sdev);
264 
265 	if (shost->hostt->slave_alloc) {
266 		ret = shost->hostt->slave_alloc(sdev);
267 		if (ret) {
268 			/*
269 			 * if LLDD reports slave not present, don't clutter
270 			 * console with alloc failure messages
271 
272 
273 			 */
274 			if (ret == -ENXIO)
275 				display_failure_msg = 0;
276 			goto out_device_destroy;
277 		}
278 	}
279 
280 	return sdev;
281 
282 out_device_destroy:
283 	transport_destroy_device(&sdev->sdev_gendev);
284 	scsi_free_queue(sdev->request_queue);
285 	put_device(&sdev->sdev_gendev);
286 out:
287 	if (display_failure_msg)
288 		printk(ALLOC_FAILURE_MSG, __FUNCTION__);
289 	return NULL;
290 }
291 
292 static void scsi_target_dev_release(struct device *dev)
293 {
294 	struct device *parent = dev->parent;
295 	struct scsi_target *starget = to_scsi_target(dev);
296 	kfree(starget);
297 	put_device(parent);
298 }
299 
300 int scsi_is_target_device(const struct device *dev)
301 {
302 	return dev->release == scsi_target_dev_release;
303 }
304 EXPORT_SYMBOL(scsi_is_target_device);
305 
306 static struct scsi_target *__scsi_find_target(struct device *parent,
307 					      int channel, uint id)
308 {
309 	struct scsi_target *starget, *found_starget = NULL;
310 	struct Scsi_Host *shost = dev_to_shost(parent);
311 	/*
312 	 * Search for an existing target for this sdev.
313 	 */
314 	list_for_each_entry(starget, &shost->__targets, siblings) {
315 		if (starget->id == id &&
316 		    starget->channel == channel) {
317 			found_starget = starget;
318 			break;
319 		}
320 	}
321 	if (found_starget)
322 		get_device(&found_starget->dev);
323 
324 	return found_starget;
325 }
326 
327 static struct scsi_target *scsi_alloc_target(struct device *parent,
328 					     int channel, uint id)
329 {
330 	struct Scsi_Host *shost = dev_to_shost(parent);
331 	struct device *dev = NULL;
332 	unsigned long flags;
333 	const int size = sizeof(struct scsi_target)
334 		+ shost->transportt->target_size;
335 	struct scsi_target *starget = kmalloc(size, GFP_ATOMIC);
336 	struct scsi_target *found_target;
337 
338 	if (!starget) {
339 		printk(KERN_ERR "%s: allocation failure\n", __FUNCTION__);
340 		return NULL;
341 	}
342 	memset(starget, 0, size);
343 	dev = &starget->dev;
344 	device_initialize(dev);
345 	starget->reap_ref = 1;
346 	dev->parent = get_device(parent);
347 	dev->release = scsi_target_dev_release;
348 	sprintf(dev->bus_id, "target%d:%d:%d",
349 		shost->host_no, channel, id);
350 	starget->id = id;
351 	starget->channel = channel;
352 	INIT_LIST_HEAD(&starget->siblings);
353 	INIT_LIST_HEAD(&starget->devices);
354 	spin_lock_irqsave(shost->host_lock, flags);
355 
356 	found_target = __scsi_find_target(parent, channel, id);
357 	if (found_target)
358 		goto found;
359 
360 	list_add_tail(&starget->siblings, &shost->__targets);
361 	spin_unlock_irqrestore(shost->host_lock, flags);
362 	/* allocate and add */
363 	transport_setup_device(&starget->dev);
364 	device_add(&starget->dev);
365 	transport_add_device(&starget->dev);
366 	return starget;
367 
368  found:
369 	found_target->reap_ref++;
370 	spin_unlock_irqrestore(shost->host_lock, flags);
371 	put_device(parent);
372 	kfree(starget);
373 	return found_target;
374 }
375 
376 /**
377  * scsi_target_reap - check to see if target is in use and destroy if not
378  *
379  * @starget: target to be checked
380  *
381  * This is used after removing a LUN or doing a last put of the target
382  * it checks atomically that nothing is using the target and removes
383  * it if so.
384  */
385 void scsi_target_reap(struct scsi_target *starget)
386 {
387 	struct Scsi_Host *shost = dev_to_shost(starget->dev.parent);
388 	unsigned long flags;
389 	spin_lock_irqsave(shost->host_lock, flags);
390 
391 	if (--starget->reap_ref == 0 && list_empty(&starget->devices)) {
392 		list_del_init(&starget->siblings);
393 		spin_unlock_irqrestore(shost->host_lock, flags);
394 		device_del(&starget->dev);
395 		transport_unregister_device(&starget->dev);
396 		put_device(&starget->dev);
397 		return;
398 	}
399 	spin_unlock_irqrestore(shost->host_lock, flags);
400 }
401 
402 /**
403  * scsi_probe_lun - probe a single LUN using a SCSI INQUIRY
404  * @sreq:	used to send the INQUIRY
405  * @inq_result:	area to store the INQUIRY result
406  * @bflags:	store any bflags found here
407  *
408  * Description:
409  *     Probe the lun associated with @sreq using a standard SCSI INQUIRY;
410  *
411  *     If the INQUIRY is successful, sreq->sr_result is zero and: the
412  *     INQUIRY data is in @inq_result; the scsi_level and INQUIRY length
413  *     are copied to the Scsi_Device at @sreq->sr_device (sdev);
414  *     any flags value is stored in *@bflags.
415  **/
416 static void scsi_probe_lun(struct scsi_request *sreq, char *inq_result,
417 			   int *bflags)
418 {
419 	struct scsi_device *sdev = sreq->sr_device;	/* a bit ugly */
420 	unsigned char scsi_cmd[MAX_COMMAND_SIZE];
421 	int first_inquiry_len, try_inquiry_len, next_inquiry_len;
422 	int response_len = 0;
423 	int pass, count;
424 	struct scsi_sense_hdr sshdr;
425 
426 	*bflags = 0;
427 
428 	/* Perform up to 3 passes.  The first pass uses a conservative
429 	 * transfer length of 36 unless sdev->inquiry_len specifies a
430 	 * different value. */
431 	first_inquiry_len = sdev->inquiry_len ? sdev->inquiry_len : 36;
432 	try_inquiry_len = first_inquiry_len;
433 	pass = 1;
434 
435  next_pass:
436 	SCSI_LOG_SCAN_BUS(3, printk(KERN_INFO "scsi scan: INQUIRY pass %d "
437 			"to host %d channel %d id %d lun %d, length %d\n",
438 			pass, sdev->host->host_no, sdev->channel,
439 			sdev->id, sdev->lun, try_inquiry_len));
440 
441 	/* Each pass gets up to three chances to ignore Unit Attention */
442 	for (count = 0; count < 3; ++count) {
443 		memset(scsi_cmd, 0, 6);
444 		scsi_cmd[0] = INQUIRY;
445 		scsi_cmd[4] = (unsigned char) try_inquiry_len;
446 		sreq->sr_cmd_len = 0;
447 		sreq->sr_data_direction = DMA_FROM_DEVICE;
448 
449 		memset(inq_result, 0, try_inquiry_len);
450 		scsi_wait_req(sreq, (void *) scsi_cmd, (void *) inq_result,
451 				try_inquiry_len,
452 				HZ/2 + HZ*scsi_inq_timeout, 3);
453 
454 		SCSI_LOG_SCAN_BUS(3, printk(KERN_INFO "scsi scan: INQUIRY %s "
455 				"with code 0x%x\n",
456 				sreq->sr_result ? "failed" : "successful",
457 				sreq->sr_result));
458 
459 		if (sreq->sr_result) {
460 			/*
461 			 * not-ready to ready transition [asc/ascq=0x28/0x0]
462 			 * or power-on, reset [asc/ascq=0x29/0x0], continue.
463 			 * INQUIRY should not yield UNIT_ATTENTION
464 			 * but many buggy devices do so anyway.
465 			 */
466 			if ((driver_byte(sreq->sr_result) & DRIVER_SENSE) &&
467 			    scsi_request_normalize_sense(sreq, &sshdr)) {
468 				if ((sshdr.sense_key == UNIT_ATTENTION) &&
469 				    ((sshdr.asc == 0x28) ||
470 				     (sshdr.asc == 0x29)) &&
471 				    (sshdr.ascq == 0))
472 					continue;
473 			}
474 		}
475 		break;
476 	}
477 
478 	if (sreq->sr_result == 0) {
479 		response_len = (unsigned char) inq_result[4] + 5;
480 		if (response_len > 255)
481 			response_len = first_inquiry_len;	/* sanity */
482 
483 		/*
484 		 * Get any flags for this device.
485 		 *
486 		 * XXX add a bflags to Scsi_Device, and replace the
487 		 * corresponding bit fields in Scsi_Device, so bflags
488 		 * need not be passed as an argument.
489 		 */
490 		*bflags = scsi_get_device_flags(sdev, &inq_result[8],
491 				&inq_result[16]);
492 
493 		/* When the first pass succeeds we gain information about
494 		 * what larger transfer lengths might work. */
495 		if (pass == 1) {
496 			if (BLIST_INQUIRY_36 & *bflags)
497 				next_inquiry_len = 36;
498 			else if (BLIST_INQUIRY_58 & *bflags)
499 				next_inquiry_len = 58;
500 			else if (sdev->inquiry_len)
501 				next_inquiry_len = sdev->inquiry_len;
502 			else
503 				next_inquiry_len = response_len;
504 
505 			/* If more data is available perform the second pass */
506 			if (next_inquiry_len > try_inquiry_len) {
507 				try_inquiry_len = next_inquiry_len;
508 				pass = 2;
509 				goto next_pass;
510 			}
511 		}
512 
513 	} else if (pass == 2) {
514 		printk(KERN_INFO "scsi scan: %d byte inquiry failed.  "
515 				"Consider BLIST_INQUIRY_36 for this device\n",
516 				try_inquiry_len);
517 
518 		/* If this pass failed, the third pass goes back and transfers
519 		 * the same amount as we successfully got in the first pass. */
520 		try_inquiry_len = first_inquiry_len;
521 		pass = 3;
522 		goto next_pass;
523 	}
524 
525 	/* If the last transfer attempt got an error, assume the
526 	 * peripheral doesn't exist or is dead. */
527 	if (sreq->sr_result)
528 		return;
529 
530 	/* Don't report any more data than the device says is valid */
531 	sdev->inquiry_len = min(try_inquiry_len, response_len);
532 
533 	/*
534 	 * XXX Abort if the response length is less than 36? If less than
535 	 * 32, the lookup of the device flags (above) could be invalid,
536 	 * and it would be possible to take an incorrect action - we do
537 	 * not want to hang because of a short INQUIRY. On the flip side,
538 	 * if the device is spun down or becoming ready (and so it gives a
539 	 * short INQUIRY), an abort here prevents any further use of the
540 	 * device, including spin up.
541 	 *
542 	 * Related to the above issue:
543 	 *
544 	 * XXX Devices (disk or all?) should be sent a TEST UNIT READY,
545 	 * and if not ready, sent a START_STOP to start (maybe spin up) and
546 	 * then send the INQUIRY again, since the INQUIRY can change after
547 	 * a device is initialized.
548 	 *
549 	 * Ideally, start a device if explicitly asked to do so.  This
550 	 * assumes that a device is spun up on power on, spun down on
551 	 * request, and then spun up on request.
552 	 */
553 
554 	/*
555 	 * The scanning code needs to know the scsi_level, even if no
556 	 * device is attached at LUN 0 (SCSI_SCAN_TARGET_PRESENT) so
557 	 * non-zero LUNs can be scanned.
558 	 */
559 	sdev->scsi_level = inq_result[2] & 0x07;
560 	if (sdev->scsi_level >= 2 ||
561 	    (sdev->scsi_level == 1 && (inq_result[3] & 0x0f) == 1))
562 		sdev->scsi_level++;
563 
564 	return;
565 }
566 
567 /**
568  * scsi_add_lun - allocate and fully initialze a Scsi_Device
569  * @sdevscan:	holds information to be stored in the new Scsi_Device
570  * @sdevnew:	store the address of the newly allocated Scsi_Device
571  * @inq_result:	holds the result of a previous INQUIRY to the LUN
572  * @bflags:	black/white list flag
573  *
574  * Description:
575  *     Allocate and initialize a Scsi_Device matching sdevscan. Optionally
576  *     set fields based on values in *@bflags. If @sdevnew is not
577  *     NULL, store the address of the new Scsi_Device in *@sdevnew (needed
578  *     when scanning a particular LUN).
579  *
580  * Return:
581  *     SCSI_SCAN_NO_RESPONSE: could not allocate or setup a Scsi_Device
582  *     SCSI_SCAN_LUN_PRESENT: a new Scsi_Device was allocated and initialized
583  **/
584 static int scsi_add_lun(struct scsi_device *sdev, char *inq_result, int *bflags)
585 {
586 	/*
587 	 * XXX do not save the inquiry, since it can change underneath us,
588 	 * save just vendor/model/rev.
589 	 *
590 	 * Rather than save it and have an ioctl that retrieves the saved
591 	 * value, have an ioctl that executes the same INQUIRY code used
592 	 * in scsi_probe_lun, let user level programs doing INQUIRY
593 	 * scanning run at their own risk, or supply a user level program
594 	 * that can correctly scan.
595 	 */
596 	sdev->inquiry = kmalloc(sdev->inquiry_len, GFP_ATOMIC);
597 	if (sdev->inquiry == NULL) {
598 		return SCSI_SCAN_NO_RESPONSE;
599 	}
600 
601 	memcpy(sdev->inquiry, inq_result, sdev->inquiry_len);
602 	sdev->vendor = (char *) (sdev->inquiry + 8);
603 	sdev->model = (char *) (sdev->inquiry + 16);
604 	sdev->rev = (char *) (sdev->inquiry + 32);
605 
606 	if (*bflags & BLIST_ISROM) {
607 		/*
608 		 * It would be better to modify sdev->type, and set
609 		 * sdev->removable, but then the print_inquiry() output
610 		 * would not show TYPE_ROM; if print_inquiry() is removed
611 		 * the issue goes away.
612 		 */
613 		inq_result[0] = TYPE_ROM;
614 		inq_result[1] |= 0x80;	/* removable */
615 	} else if (*bflags & BLIST_NO_ULD_ATTACH)
616 		sdev->no_uld_attach = 1;
617 
618 	switch (sdev->type = (inq_result[0] & 0x1f)) {
619 	case TYPE_TAPE:
620 	case TYPE_DISK:
621 	case TYPE_PRINTER:
622 	case TYPE_MOD:
623 	case TYPE_PROCESSOR:
624 	case TYPE_SCANNER:
625 	case TYPE_MEDIUM_CHANGER:
626 	case TYPE_ENCLOSURE:
627 	case TYPE_COMM:
628 		sdev->writeable = 1;
629 		break;
630 	case TYPE_WORM:
631 	case TYPE_ROM:
632 		sdev->writeable = 0;
633 		break;
634 	default:
635 		printk(KERN_INFO "scsi: unknown device type %d\n", sdev->type);
636 	}
637 
638 	print_inquiry(inq_result);
639 
640 	/*
641 	 * For a peripheral qualifier (PQ) value of 1 (001b), the SCSI
642 	 * spec says: The device server is capable of supporting the
643 	 * specified peripheral device type on this logical unit. However,
644 	 * the physical device is not currently connected to this logical
645 	 * unit.
646 	 *
647 	 * The above is vague, as it implies that we could treat 001 and
648 	 * 011 the same. Stay compatible with previous code, and create a
649 	 * Scsi_Device for a PQ of 1
650 	 *
651 	 * Don't set the device offline here; rather let the upper
652 	 * level drivers eval the PQ to decide whether they should
653 	 * attach. So remove ((inq_result[0] >> 5) & 7) == 1 check.
654 	 */
655 
656 	sdev->inq_periph_qual = (inq_result[0] >> 5) & 7;
657 	sdev->removable = (0x80 & inq_result[1]) >> 7;
658 	sdev->lockable = sdev->removable;
659 	sdev->soft_reset = (inq_result[7] & 1) && ((inq_result[3] & 7) == 2);
660 
661 	if (sdev->scsi_level >= SCSI_3 || (sdev->inquiry_len > 56 &&
662 		inq_result[56] & 0x04))
663 		sdev->ppr = 1;
664 	if (inq_result[7] & 0x60)
665 		sdev->wdtr = 1;
666 	if (inq_result[7] & 0x10)
667 		sdev->sdtr = 1;
668 
669 	sprintf(sdev->devfs_name, "scsi/host%d/bus%d/target%d/lun%d",
670 				sdev->host->host_no, sdev->channel,
671 				sdev->id, sdev->lun);
672 
673 	/*
674 	 * End driverfs/devfs code.
675 	 */
676 
677 	if ((sdev->scsi_level >= SCSI_2) && (inq_result[7] & 2) &&
678 	    !(*bflags & BLIST_NOTQ))
679 		sdev->tagged_supported = 1;
680 	/*
681 	 * Some devices (Texel CD ROM drives) have handshaking problems
682 	 * when used with the Seagate controllers. borken is initialized
683 	 * to 1, and then set it to 0 here.
684 	 */
685 	if ((*bflags & BLIST_BORKEN) == 0)
686 		sdev->borken = 0;
687 
688 	/*
689 	 * Apparently some really broken devices (contrary to the SCSI
690 	 * standards) need to be selected without asserting ATN
691 	 */
692 	if (*bflags & BLIST_SELECT_NO_ATN)
693 		sdev->select_no_atn = 1;
694 
695 	/*
696 	 * Some devices may not want to have a start command automatically
697 	 * issued when a device is added.
698 	 */
699 	if (*bflags & BLIST_NOSTARTONADD)
700 		sdev->no_start_on_add = 1;
701 
702 	if (*bflags & BLIST_SINGLELUN)
703 		sdev->single_lun = 1;
704 
705 
706 	sdev->use_10_for_rw = 1;
707 
708 	if (*bflags & BLIST_MS_SKIP_PAGE_08)
709 		sdev->skip_ms_page_8 = 1;
710 
711 	if (*bflags & BLIST_MS_SKIP_PAGE_3F)
712 		sdev->skip_ms_page_3f = 1;
713 
714 	if (*bflags & BLIST_USE_10_BYTE_MS)
715 		sdev->use_10_for_ms = 1;
716 
717 	/* set the device running here so that slave configure
718 	 * may do I/O */
719 	scsi_device_set_state(sdev, SDEV_RUNNING);
720 
721 	if (*bflags & BLIST_MS_192_BYTES_FOR_3F)
722 		sdev->use_192_bytes_for_3f = 1;
723 
724 	if (*bflags & BLIST_NOT_LOCKABLE)
725 		sdev->lockable = 0;
726 
727 	if (*bflags & BLIST_RETRY_HWERROR)
728 		sdev->retry_hwerror = 1;
729 
730 	transport_configure_device(&sdev->sdev_gendev);
731 
732 	if (sdev->host->hostt->slave_configure)
733 		sdev->host->hostt->slave_configure(sdev);
734 
735 	/*
736 	 * Ok, the device is now all set up, we can
737 	 * register it and tell the rest of the kernel
738 	 * about it.
739 	 */
740 	scsi_sysfs_add_sdev(sdev);
741 
742 	return SCSI_SCAN_LUN_PRESENT;
743 }
744 
745 /**
746  * scsi_probe_and_add_lun - probe a LUN, if a LUN is found add it
747  * @starget:	pointer to target device structure
748  * @lun:	LUN of target device
749  * @sdevscan:	probe the LUN corresponding to this Scsi_Device
750  * @sdevnew:	store the value of any new Scsi_Device allocated
751  * @bflagsp:	store bflags here if not NULL
752  *
753  * Description:
754  *     Call scsi_probe_lun, if a LUN with an attached device is found,
755  *     allocate and set it up by calling scsi_add_lun.
756  *
757  * Return:
758  *     SCSI_SCAN_NO_RESPONSE: could not allocate or setup a Scsi_Device
759  *     SCSI_SCAN_TARGET_PRESENT: target responded, but no device is
760  *         attached at the LUN
761  *     SCSI_SCAN_LUN_PRESENT: a new Scsi_Device was allocated and initialized
762  **/
763 static int scsi_probe_and_add_lun(struct scsi_target *starget,
764 				  uint lun, int *bflagsp,
765 				  struct scsi_device **sdevp, int rescan,
766 				  void *hostdata)
767 {
768 	struct scsi_device *sdev;
769 	struct scsi_request *sreq;
770 	unsigned char *result;
771 	int bflags, res = SCSI_SCAN_NO_RESPONSE;
772 	struct Scsi_Host *shost = dev_to_shost(starget->dev.parent);
773 
774 	/*
775 	 * The rescan flag is used as an optimization, the first scan of a
776 	 * host adapter calls into here with rescan == 0.
777 	 */
778 	if (rescan) {
779 		sdev = scsi_device_lookup_by_target(starget, lun);
780 		if (sdev) {
781 			SCSI_LOG_SCAN_BUS(3, printk(KERN_INFO
782 				"scsi scan: device exists on %s\n",
783 				sdev->sdev_gendev.bus_id));
784 			if (sdevp)
785 				*sdevp = sdev;
786 			else
787 				scsi_device_put(sdev);
788 
789 			if (bflagsp)
790 				*bflagsp = scsi_get_device_flags(sdev,
791 								 sdev->vendor,
792 								 sdev->model);
793 			return SCSI_SCAN_LUN_PRESENT;
794 		}
795 	}
796 
797 	sdev = scsi_alloc_sdev(starget, lun, hostdata);
798 	if (!sdev)
799 		goto out;
800 	sreq = scsi_allocate_request(sdev, GFP_ATOMIC);
801 	if (!sreq)
802 		goto out_free_sdev;
803 	result = kmalloc(256, GFP_ATOMIC |
804 			((shost->unchecked_isa_dma) ? __GFP_DMA : 0));
805 	if (!result)
806 		goto out_free_sreq;
807 
808 	scsi_probe_lun(sreq, result, &bflags);
809 	if (sreq->sr_result)
810 		goto out_free_result;
811 
812 	/*
813 	 * result contains valid SCSI INQUIRY data.
814 	 */
815 	if ((result[0] >> 5) == 3) {
816 		/*
817 		 * For a Peripheral qualifier 3 (011b), the SCSI
818 		 * spec says: The device server is not capable of
819 		 * supporting a physical device on this logical
820 		 * unit.
821 		 *
822 		 * For disks, this implies that there is no
823 		 * logical disk configured at sdev->lun, but there
824 		 * is a target id responding.
825 		 */
826 		SCSI_LOG_SCAN_BUS(3, printk(KERN_INFO
827 					"scsi scan: peripheral qualifier of 3,"
828 					" no device added\n"));
829 		res = SCSI_SCAN_TARGET_PRESENT;
830 		goto out_free_result;
831 	}
832 
833 	res = scsi_add_lun(sdev, result, &bflags);
834 	if (res == SCSI_SCAN_LUN_PRESENT) {
835 		if (bflags & BLIST_KEY) {
836 			sdev->lockable = 0;
837 			scsi_unlock_floptical(sreq, result);
838 		}
839 		if (bflagsp)
840 			*bflagsp = bflags;
841 	}
842 
843  out_free_result:
844 	kfree(result);
845  out_free_sreq:
846 	scsi_release_request(sreq);
847  out_free_sdev:
848 	if (res == SCSI_SCAN_LUN_PRESENT) {
849 		if (sdevp) {
850 			scsi_device_get(sdev);
851 			*sdevp = sdev;
852 		}
853 	} else {
854 		if (sdev->host->hostt->slave_destroy)
855 			sdev->host->hostt->slave_destroy(sdev);
856 		transport_destroy_device(&sdev->sdev_gendev);
857 		put_device(&sdev->sdev_gendev);
858 	}
859  out:
860 	return res;
861 }
862 
863 /**
864  * scsi_sequential_lun_scan - sequentially scan a SCSI target
865  * @starget:	pointer to target structure to scan
866  * @bflags:	black/white list flag for LUN 0
867  * @lun0_res:	result of scanning LUN 0
868  *
869  * Description:
870  *     Generally, scan from LUN 1 (LUN 0 is assumed to already have been
871  *     scanned) to some maximum lun until a LUN is found with no device
872  *     attached. Use the bflags to figure out any oddities.
873  *
874  *     Modifies sdevscan->lun.
875  **/
876 static void scsi_sequential_lun_scan(struct scsi_target *starget,
877 				     int bflags, int lun0_res, int scsi_level,
878 				     int rescan)
879 {
880 	unsigned int sparse_lun, lun, max_dev_lun;
881 	struct Scsi_Host *shost = dev_to_shost(starget->dev.parent);
882 
883 	SCSI_LOG_SCAN_BUS(3, printk(KERN_INFO "scsi scan: Sequential scan of"
884 				    "%s\n", starget->dev.bus_id));
885 
886 	max_dev_lun = min(max_scsi_luns, shost->max_lun);
887 	/*
888 	 * If this device is known to support sparse multiple units,
889 	 * override the other settings, and scan all of them. Normally,
890 	 * SCSI-3 devices should be scanned via the REPORT LUNS.
891 	 */
892 	if (bflags & BLIST_SPARSELUN) {
893 		max_dev_lun = shost->max_lun;
894 		sparse_lun = 1;
895 	} else
896 		sparse_lun = 0;
897 
898 	/*
899 	 * If not sparse lun and no device attached at LUN 0 do not scan
900 	 * any further.
901 	 */
902 	if (!sparse_lun && (lun0_res != SCSI_SCAN_LUN_PRESENT))
903 		return;
904 
905 	/*
906 	 * If less than SCSI_1_CSS, and no special lun scaning, stop
907 	 * scanning; this matches 2.4 behaviour, but could just be a bug
908 	 * (to continue scanning a SCSI_1_CSS device).
909 	 *
910 	 * This test is broken.  We might not have any device on lun0 for
911 	 * a sparselun device, and if that's the case then how would we
912 	 * know the real scsi_level, eh?  It might make sense to just not
913 	 * scan any SCSI_1 device for non-0 luns, but that check would best
914 	 * go into scsi_alloc_sdev() and just have it return null when asked
915 	 * to alloc an sdev for lun > 0 on an already found SCSI_1 device.
916 	 *
917 	if ((sdevscan->scsi_level < SCSI_1_CCS) &&
918 	    ((bflags & (BLIST_FORCELUN | BLIST_SPARSELUN | BLIST_MAX5LUN))
919 	     == 0))
920 		return;
921 	 */
922 	/*
923 	 * If this device is known to support multiple units, override
924 	 * the other settings, and scan all of them.
925 	 */
926 	if (bflags & BLIST_FORCELUN)
927 		max_dev_lun = shost->max_lun;
928 	/*
929 	 * REGAL CDC-4X: avoid hang after LUN 4
930 	 */
931 	if (bflags & BLIST_MAX5LUN)
932 		max_dev_lun = min(5U, max_dev_lun);
933 	/*
934 	 * Do not scan SCSI-2 or lower device past LUN 7, unless
935 	 * BLIST_LARGELUN.
936 	 */
937 	if (scsi_level < SCSI_3 && !(bflags & BLIST_LARGELUN))
938 		max_dev_lun = min(8U, max_dev_lun);
939 
940 	/*
941 	 * We have already scanned LUN 0, so start at LUN 1. Keep scanning
942 	 * until we reach the max, or no LUN is found and we are not
943 	 * sparse_lun.
944 	 */
945 	for (lun = 1; lun < max_dev_lun; ++lun)
946 		if ((scsi_probe_and_add_lun(starget, lun, NULL, NULL, rescan,
947 					    NULL) != SCSI_SCAN_LUN_PRESENT) &&
948 		    !sparse_lun)
949 			return;
950 }
951 
952 /**
953  * scsilun_to_int: convert a scsi_lun to an int
954  * @scsilun:	struct scsi_lun to be converted.
955  *
956  * Description:
957  *     Convert @scsilun from a struct scsi_lun to a four byte host byte-ordered
958  *     integer, and return the result. The caller must check for
959  *     truncation before using this function.
960  *
961  * Notes:
962  *     The struct scsi_lun is assumed to be four levels, with each level
963  *     effectively containing a SCSI byte-ordered (big endian) short; the
964  *     addressing bits of each level are ignored (the highest two bits).
965  *     For a description of the LUN format, post SCSI-3 see the SCSI
966  *     Architecture Model, for SCSI-3 see the SCSI Controller Commands.
967  *
968  *     Given a struct scsi_lun of: 0a 04 0b 03 00 00 00 00, this function returns
969  *     the integer: 0x0b030a04
970  **/
971 static int scsilun_to_int(struct scsi_lun *scsilun)
972 {
973 	int i;
974 	unsigned int lun;
975 
976 	lun = 0;
977 	for (i = 0; i < sizeof(lun); i += 2)
978 		lun = lun | (((scsilun->scsi_lun[i] << 8) |
979 			      scsilun->scsi_lun[i + 1]) << (i * 8));
980 	return lun;
981 }
982 
983 /**
984  * scsi_report_lun_scan - Scan using SCSI REPORT LUN results
985  * @sdevscan:	scan the host, channel, and id of this Scsi_Device
986  *
987  * Description:
988  *     If @sdevscan is for a SCSI-3 or up device, send a REPORT LUN
989  *     command, and scan the resulting list of LUNs by calling
990  *     scsi_probe_and_add_lun.
991  *
992  *     Modifies sdevscan->lun.
993  *
994  * Return:
995  *     0: scan completed (or no memory, so further scanning is futile)
996  *     1: no report lun scan, or not configured
997  **/
998 static int scsi_report_lun_scan(struct scsi_device *sdev, int bflags,
999 				int rescan)
1000 {
1001 	char devname[64];
1002 	unsigned char scsi_cmd[MAX_COMMAND_SIZE];
1003 	unsigned int length;
1004 	unsigned int lun;
1005 	unsigned int num_luns;
1006 	unsigned int retries;
1007 	struct scsi_lun *lunp, *lun_data;
1008 	struct scsi_request *sreq;
1009 	u8 *data;
1010 	struct scsi_sense_hdr sshdr;
1011 	struct scsi_target *starget = scsi_target(sdev);
1012 
1013 	/*
1014 	 * Only support SCSI-3 and up devices if BLIST_NOREPORTLUN is not set.
1015 	 * Also allow SCSI-2 if BLIST_REPORTLUN2 is set and host adapter does
1016 	 * support more than 8 LUNs.
1017 	 */
1018 	if ((bflags & BLIST_NOREPORTLUN) ||
1019 	     sdev->scsi_level < SCSI_2 ||
1020 	    (sdev->scsi_level < SCSI_3 &&
1021 	     (!(bflags & BLIST_REPORTLUN2) || sdev->host->max_lun <= 8)) )
1022 		return 1;
1023 	if (bflags & BLIST_NOLUN)
1024 		return 0;
1025 
1026 	sreq = scsi_allocate_request(sdev, GFP_ATOMIC);
1027 	if (!sreq)
1028 		goto out;
1029 
1030 	sprintf(devname, "host %d channel %d id %d",
1031 		sdev->host->host_no, sdev->channel, sdev->id);
1032 
1033 	/*
1034 	 * Allocate enough to hold the header (the same size as one scsi_lun)
1035 	 * plus the max number of luns we are requesting.
1036 	 *
1037 	 * Reallocating and trying again (with the exact amount we need)
1038 	 * would be nice, but then we need to somehow limit the size
1039 	 * allocated based on the available memory and the limits of
1040 	 * kmalloc - we don't want a kmalloc() failure of a huge value to
1041 	 * prevent us from finding any LUNs on this target.
1042 	 */
1043 	length = (max_scsi_report_luns + 1) * sizeof(struct scsi_lun);
1044 	lun_data = kmalloc(length, GFP_ATOMIC |
1045 			   (sdev->host->unchecked_isa_dma ? __GFP_DMA : 0));
1046 	if (!lun_data)
1047 		goto out_release_request;
1048 
1049 	scsi_cmd[0] = REPORT_LUNS;
1050 
1051 	/*
1052 	 * bytes 1 - 5: reserved, set to zero.
1053 	 */
1054 	memset(&scsi_cmd[1], 0, 5);
1055 
1056 	/*
1057 	 * bytes 6 - 9: length of the command.
1058 	 */
1059 	scsi_cmd[6] = (unsigned char) (length >> 24) & 0xff;
1060 	scsi_cmd[7] = (unsigned char) (length >> 16) & 0xff;
1061 	scsi_cmd[8] = (unsigned char) (length >> 8) & 0xff;
1062 	scsi_cmd[9] = (unsigned char) length & 0xff;
1063 
1064 	scsi_cmd[10] = 0;	/* reserved */
1065 	scsi_cmd[11] = 0;	/* control */
1066 	sreq->sr_cmd_len = 0;
1067 	sreq->sr_data_direction = DMA_FROM_DEVICE;
1068 
1069 	/*
1070 	 * We can get a UNIT ATTENTION, for example a power on/reset, so
1071 	 * retry a few times (like sd.c does for TEST UNIT READY).
1072 	 * Experience shows some combinations of adapter/devices get at
1073 	 * least two power on/resets.
1074 	 *
1075 	 * Illegal requests (for devices that do not support REPORT LUNS)
1076 	 * should come through as a check condition, and will not generate
1077 	 * a retry.
1078 	 */
1079 	for (retries = 0; retries < 3; retries++) {
1080 		SCSI_LOG_SCAN_BUS(3, printk (KERN_INFO "scsi scan: Sending"
1081 				" REPORT LUNS to %s (try %d)\n", devname,
1082 				retries));
1083 		scsi_wait_req(sreq, scsi_cmd, lun_data, length,
1084 				SCSI_TIMEOUT + 4*HZ, 3);
1085 		SCSI_LOG_SCAN_BUS(3, printk (KERN_INFO "scsi scan: REPORT LUNS"
1086 				" %s (try %d) result 0x%x\n", sreq->sr_result
1087 				?  "failed" : "successful", retries,
1088 				sreq->sr_result));
1089 		if (sreq->sr_result == 0)
1090 			break;
1091 		else if (scsi_request_normalize_sense(sreq, &sshdr)) {
1092 			if (sshdr.sense_key != UNIT_ATTENTION)
1093 				break;
1094 		}
1095 	}
1096 
1097 	if (sreq->sr_result) {
1098 		/*
1099 		 * The device probably does not support a REPORT LUN command
1100 		 */
1101 		kfree(lun_data);
1102 		scsi_release_request(sreq);
1103 		return 1;
1104 	}
1105 	scsi_release_request(sreq);
1106 
1107 	/*
1108 	 * Get the length from the first four bytes of lun_data.
1109 	 */
1110 	data = (u8 *) lun_data->scsi_lun;
1111 	length = ((data[0] << 24) | (data[1] << 16) |
1112 		  (data[2] << 8) | (data[3] << 0));
1113 
1114 	num_luns = (length / sizeof(struct scsi_lun));
1115 	if (num_luns > max_scsi_report_luns) {
1116 		printk(KERN_WARNING "scsi: On %s only %d (max_scsi_report_luns)"
1117 		       " of %d luns reported, try increasing"
1118 		       " max_scsi_report_luns.\n", devname,
1119 		       max_scsi_report_luns, num_luns);
1120 		num_luns = max_scsi_report_luns;
1121 	}
1122 
1123 	SCSI_LOG_SCAN_BUS(3, printk (KERN_INFO "scsi scan: REPORT LUN scan of"
1124 			" host %d channel %d id %d\n", sdev->host->host_no,
1125 			sdev->channel, sdev->id));
1126 
1127 	/*
1128 	 * Scan the luns in lun_data. The entry at offset 0 is really
1129 	 * the header, so start at 1 and go up to and including num_luns.
1130 	 */
1131 	for (lunp = &lun_data[1]; lunp <= &lun_data[num_luns]; lunp++) {
1132 		lun = scsilun_to_int(lunp);
1133 
1134 		/*
1135 		 * Check if the unused part of lunp is non-zero, and so
1136 		 * does not fit in lun.
1137 		 */
1138 		if (memcmp(&lunp->scsi_lun[sizeof(lun)], "\0\0\0\0", 4)) {
1139 			int i;
1140 
1141 			/*
1142 			 * Output an error displaying the LUN in byte order,
1143 			 * this differs from what linux would print for the
1144 			 * integer LUN value.
1145 			 */
1146 			printk(KERN_WARNING "scsi: %s lun 0x", devname);
1147 			data = (char *)lunp->scsi_lun;
1148 			for (i = 0; i < sizeof(struct scsi_lun); i++)
1149 				printk("%02x", data[i]);
1150 			printk(" has a LUN larger than currently supported.\n");
1151 		} else if (lun == 0) {
1152 			/*
1153 			 * LUN 0 has already been scanned.
1154 			 */
1155 		} else if (lun > sdev->host->max_lun) {
1156 			printk(KERN_WARNING "scsi: %s lun%d has a LUN larger"
1157 			       " than allowed by the host adapter\n",
1158 			       devname, lun);
1159 		} else {
1160 			int res;
1161 
1162 			res = scsi_probe_and_add_lun(starget,
1163 				lun, NULL, NULL, rescan, NULL);
1164 			if (res == SCSI_SCAN_NO_RESPONSE) {
1165 				/*
1166 				 * Got some results, but now none, abort.
1167 				 */
1168 				printk(KERN_ERR "scsi: Unexpected response"
1169 				       " from %s lun %d while scanning, scan"
1170 				       " aborted\n", devname, lun);
1171 				break;
1172 			}
1173 		}
1174 	}
1175 
1176 	kfree(lun_data);
1177 	return 0;
1178 
1179  out_release_request:
1180 	scsi_release_request(sreq);
1181  out:
1182 	/*
1183 	 * We are out of memory, don't try scanning any further.
1184 	 */
1185 	printk(ALLOC_FAILURE_MSG, __FUNCTION__);
1186 	return 0;
1187 }
1188 
1189 struct scsi_device *__scsi_add_device(struct Scsi_Host *shost, uint channel,
1190 				      uint id, uint lun, void *hostdata)
1191 {
1192 	struct scsi_device *sdev;
1193 	struct device *parent = &shost->shost_gendev;
1194 	int res;
1195 	struct scsi_target *starget = scsi_alloc_target(parent, channel, id);
1196 
1197 	if (!starget)
1198 		return ERR_PTR(-ENOMEM);
1199 
1200 	get_device(&starget->dev);
1201 	down(&shost->scan_mutex);
1202 	res = scsi_probe_and_add_lun(starget, lun, NULL, &sdev, 1, hostdata);
1203 	if (res != SCSI_SCAN_LUN_PRESENT)
1204 		sdev = ERR_PTR(-ENODEV);
1205 	up(&shost->scan_mutex);
1206 	scsi_target_reap(starget);
1207 	put_device(&starget->dev);
1208 
1209 	return sdev;
1210 }
1211 EXPORT_SYMBOL(__scsi_add_device);
1212 
1213 void scsi_rescan_device(struct device *dev)
1214 {
1215 	struct scsi_driver *drv;
1216 
1217 	if (!dev->driver)
1218 		return;
1219 
1220 	drv = to_scsi_driver(dev->driver);
1221 	if (try_module_get(drv->owner)) {
1222 		if (drv->rescan)
1223 			drv->rescan(dev);
1224 		module_put(drv->owner);
1225 	}
1226 }
1227 EXPORT_SYMBOL(scsi_rescan_device);
1228 
1229 /**
1230  * scsi_scan_target - scan a target id, possibly including all LUNs on the
1231  *     target.
1232  * @sdevsca:	Scsi_Device handle for scanning
1233  * @shost:	host to scan
1234  * @channel:	channel to scan
1235  * @id:		target id to scan
1236  *
1237  * Description:
1238  *     Scan the target id on @shost, @channel, and @id. Scan at least LUN
1239  *     0, and possibly all LUNs on the target id.
1240  *
1241  *     Use the pre-allocated @sdevscan as a handle for the scanning. This
1242  *     function sets sdevscan->host, sdevscan->id and sdevscan->lun; the
1243  *     scanning functions modify sdevscan->lun.
1244  *
1245  *     First try a REPORT LUN scan, if that does not scan the target, do a
1246  *     sequential scan of LUNs on the target id.
1247  **/
1248 void scsi_scan_target(struct device *parent, unsigned int channel,
1249 		      unsigned int id, unsigned int lun, int rescan)
1250 {
1251 	struct Scsi_Host *shost = dev_to_shost(parent);
1252 	int bflags = 0;
1253 	int res;
1254 	struct scsi_device *sdev = NULL;
1255 	struct scsi_target *starget;
1256 
1257 	if (shost->this_id == id)
1258 		/*
1259 		 * Don't scan the host adapter
1260 		 */
1261 		return;
1262 
1263 
1264 	starget = scsi_alloc_target(parent, channel, id);
1265 
1266 	if (!starget)
1267 		return;
1268 
1269 	get_device(&starget->dev);
1270 	if (lun != SCAN_WILD_CARD) {
1271 		/*
1272 		 * Scan for a specific host/chan/id/lun.
1273 		 */
1274 		scsi_probe_and_add_lun(starget, lun, NULL, NULL, rescan, NULL);
1275 		goto out_reap;
1276 	}
1277 
1278 	/*
1279 	 * Scan LUN 0, if there is some response, scan further. Ideally, we
1280 	 * would not configure LUN 0 until all LUNs are scanned.
1281 	 */
1282 	res = scsi_probe_and_add_lun(starget, 0, &bflags, &sdev, rescan, NULL);
1283 	if (res == SCSI_SCAN_LUN_PRESENT) {
1284 		if (scsi_report_lun_scan(sdev, bflags, rescan) != 0)
1285 			/*
1286 			 * The REPORT LUN did not scan the target,
1287 			 * do a sequential scan.
1288 			 */
1289 			scsi_sequential_lun_scan(starget, bflags,
1290 				       	res, sdev->scsi_level, rescan);
1291 	} else if (res == SCSI_SCAN_TARGET_PRESENT) {
1292 		/*
1293 		 * There's a target here, but lun 0 is offline so we
1294 		 * can't use the report_lun scan.  Fall back to a
1295 		 * sequential lun scan with a bflags of SPARSELUN and
1296 		 * a default scsi level of SCSI_2
1297 		 */
1298 		scsi_sequential_lun_scan(starget, BLIST_SPARSELUN,
1299 				SCSI_SCAN_TARGET_PRESENT, SCSI_2, rescan);
1300 	}
1301 	if (sdev)
1302 		scsi_device_put(sdev);
1303 
1304  out_reap:
1305 	/* now determine if the target has any children at all
1306 	 * and if not, nuke it */
1307 	scsi_target_reap(starget);
1308 
1309 	put_device(&starget->dev);
1310 }
1311 EXPORT_SYMBOL(scsi_scan_target);
1312 
1313 static void scsi_scan_channel(struct Scsi_Host *shost, unsigned int channel,
1314 			      unsigned int id, unsigned int lun, int rescan)
1315 {
1316 	uint order_id;
1317 
1318 	if (id == SCAN_WILD_CARD)
1319 		for (id = 0; id < shost->max_id; ++id) {
1320 			/*
1321 			 * XXX adapter drivers when possible (FCP, iSCSI)
1322 			 * could modify max_id to match the current max,
1323 			 * not the absolute max.
1324 			 *
1325 			 * XXX add a shost id iterator, so for example,
1326 			 * the FC ID can be the same as a target id
1327 			 * without a huge overhead of sparse id's.
1328 			 */
1329 			if (shost->reverse_ordering)
1330 				/*
1331 				 * Scan from high to low id.
1332 				 */
1333 				order_id = shost->max_id - id - 1;
1334 			else
1335 				order_id = id;
1336 			scsi_scan_target(&shost->shost_gendev, channel, order_id, lun, rescan);
1337 		}
1338 	else
1339 		scsi_scan_target(&shost->shost_gendev, channel, id, lun, rescan);
1340 }
1341 
1342 int scsi_scan_host_selected(struct Scsi_Host *shost, unsigned int channel,
1343 			    unsigned int id, unsigned int lun, int rescan)
1344 {
1345 	SCSI_LOG_SCAN_BUS(3, printk (KERN_INFO "%s: <%u:%u:%u:%u>\n",
1346 		__FUNCTION__, shost->host_no, channel, id, lun));
1347 
1348 	if (((channel != SCAN_WILD_CARD) && (channel > shost->max_channel)) ||
1349 	    ((id != SCAN_WILD_CARD) && (id > shost->max_id)) ||
1350 	    ((lun != SCAN_WILD_CARD) && (lun > shost->max_lun)))
1351 		return -EINVAL;
1352 
1353 	down(&shost->scan_mutex);
1354 	if (channel == SCAN_WILD_CARD)
1355 		for (channel = 0; channel <= shost->max_channel; channel++)
1356 			scsi_scan_channel(shost, channel, id, lun, rescan);
1357 	else
1358 		scsi_scan_channel(shost, channel, id, lun, rescan);
1359 	up(&shost->scan_mutex);
1360 
1361 	return 0;
1362 }
1363 
1364 /**
1365  * scsi_scan_host - scan the given adapter
1366  * @shost:	adapter to scan
1367  **/
1368 void scsi_scan_host(struct Scsi_Host *shost)
1369 {
1370 	scsi_scan_host_selected(shost, SCAN_WILD_CARD, SCAN_WILD_CARD,
1371 				SCAN_WILD_CARD, 0);
1372 }
1373 EXPORT_SYMBOL(scsi_scan_host);
1374 
1375 /**
1376  * scsi_scan_single_target - scan the given SCSI target
1377  * @shost:         adapter to scan
1378  * @chan:          channel to scan
1379  * @id:            target id to scan
1380  **/
1381 void scsi_scan_single_target(struct Scsi_Host *shost,
1382 	unsigned int chan, unsigned int id)
1383 {
1384 	scsi_scan_host_selected(shost, chan, id, SCAN_WILD_CARD, 1);
1385 }
1386 EXPORT_SYMBOL(scsi_scan_single_target);
1387 
1388 void scsi_forget_host(struct Scsi_Host *shost)
1389 {
1390 	struct scsi_target *starget, *tmp;
1391 	unsigned long flags;
1392 
1393 	/*
1394 	 * Ok, this look a bit strange.  We always look for the first device
1395 	 * on the list as scsi_remove_device removes them from it - thus we
1396 	 * also have to release the lock.
1397 	 * We don't need to get another reference to the device before
1398 	 * releasing the lock as we already own the reference from
1399 	 * scsi_register_device that's release in scsi_remove_device.  And
1400 	 * after that we don't look at sdev anymore.
1401 	 */
1402 	spin_lock_irqsave(shost->host_lock, flags);
1403 	list_for_each_entry_safe(starget, tmp, &shost->__targets, siblings) {
1404 		spin_unlock_irqrestore(shost->host_lock, flags);
1405 		scsi_remove_target(&starget->dev);
1406 		spin_lock_irqsave(shost->host_lock, flags);
1407 	}
1408 	spin_unlock_irqrestore(shost->host_lock, flags);
1409 }
1410 
1411 /*
1412  * Function:    scsi_get_host_dev()
1413  *
1414  * Purpose:     Create a Scsi_Device that points to the host adapter itself.
1415  *
1416  * Arguments:   SHpnt   - Host that needs a Scsi_Device
1417  *
1418  * Lock status: None assumed.
1419  *
1420  * Returns:     The Scsi_Device or NULL
1421  *
1422  * Notes:
1423  *	Attach a single Scsi_Device to the Scsi_Host - this should
1424  *	be made to look like a "pseudo-device" that points to the
1425  *	HA itself.
1426  *
1427  *	Note - this device is not accessible from any high-level
1428  *	drivers (including generics), which is probably not
1429  *	optimal.  We can add hooks later to attach
1430  */
1431 struct scsi_device *scsi_get_host_dev(struct Scsi_Host *shost)
1432 {
1433 	struct scsi_device *sdev;
1434 	struct scsi_target *starget;
1435 
1436 	starget = scsi_alloc_target(&shost->shost_gendev, 0, shost->this_id);
1437 	if (!starget)
1438 		return NULL;
1439 
1440 	sdev = scsi_alloc_sdev(starget, 0, NULL);
1441 	if (sdev) {
1442 		sdev->sdev_gendev.parent = get_device(&starget->dev);
1443 		sdev->borken = 0;
1444 	}
1445 	put_device(&starget->dev);
1446 	return sdev;
1447 }
1448 EXPORT_SYMBOL(scsi_get_host_dev);
1449 
1450 /*
1451  * Function:    scsi_free_host_dev()
1452  *
1453  * Purpose:     Free a scsi_device that points to the host adapter itself.
1454  *
1455  * Arguments:   SHpnt   - Host that needs a Scsi_Device
1456  *
1457  * Lock status: None assumed.
1458  *
1459  * Returns:     Nothing
1460  *
1461  * Notes:
1462  */
1463 void scsi_free_host_dev(struct scsi_device *sdev)
1464 {
1465 	BUG_ON(sdev->id != sdev->host->this_id);
1466 
1467 	if (sdev->host->hostt->slave_destroy)
1468 		sdev->host->hostt->slave_destroy(sdev);
1469 	transport_destroy_device(&sdev->sdev_gendev);
1470 	put_device(&sdev->sdev_gendev);
1471 }
1472 EXPORT_SYMBOL(scsi_free_host_dev);
1473 
1474