1 // SPDX-License-Identifier: GPL-2.0
2 /*
3  * scsi_scan.c
4  *
5  * Copyright (C) 2000 Eric Youngdale,
6  * Copyright (C) 2002 Patrick Mansfield
7  *
8  * The general scanning/probing algorithm is as follows, exceptions are
9  * made to it depending on device specific flags, compilation options, and
10  * global variable (boot or module load time) settings.
11  *
12  * A specific LUN is scanned via an INQUIRY command; if the LUN has a
13  * device attached, a scsi_device is allocated and setup for it.
14  *
15  * For every id of every channel on the given host:
16  *
17  * 	Scan LUN 0; if the target responds to LUN 0 (even if there is no
18  * 	device or storage attached to LUN 0):
19  *
20  * 		If LUN 0 has a device attached, allocate and setup a
21  * 		scsi_device for it.
22  *
23  * 		If target is SCSI-3 or up, issue a REPORT LUN, and scan
24  * 		all of the LUNs returned by the REPORT LUN; else,
25  * 		sequentially scan LUNs up until some maximum is reached,
26  * 		or a LUN is seen that cannot have a device attached to it.
27  */
28 
29 #include <linux/module.h>
30 #include <linux/moduleparam.h>
31 #include <linux/init.h>
32 #include <linux/blkdev.h>
33 #include <linux/delay.h>
34 #include <linux/kthread.h>
35 #include <linux/spinlock.h>
36 #include <linux/async.h>
37 #include <linux/slab.h>
38 #include <asm/unaligned.h>
39 
40 #include <scsi/scsi.h>
41 #include <scsi/scsi_cmnd.h>
42 #include <scsi/scsi_device.h>
43 #include <scsi/scsi_driver.h>
44 #include <scsi/scsi_devinfo.h>
45 #include <scsi/scsi_host.h>
46 #include <scsi/scsi_transport.h>
47 #include <scsi/scsi_dh.h>
48 #include <scsi/scsi_eh.h>
49 
50 #include "scsi_priv.h"
51 #include "scsi_logging.h"
52 
53 #define ALLOC_FAILURE_MSG	KERN_ERR "%s: Allocation failure during" \
54 	" SCSI scanning, some SCSI devices might not be configured\n"
55 
56 /*
57  * Default timeout
58  */
59 #define SCSI_TIMEOUT (2*HZ)
60 #define SCSI_REPORT_LUNS_TIMEOUT (30*HZ)
61 
62 /*
63  * Prefix values for the SCSI id's (stored in sysfs name field)
64  */
65 #define SCSI_UID_SER_NUM 'S'
66 #define SCSI_UID_UNKNOWN 'Z'
67 
68 /*
69  * Return values of some of the scanning functions.
70  *
71  * SCSI_SCAN_NO_RESPONSE: no valid response received from the target, this
72  * includes allocation or general failures preventing IO from being sent.
73  *
74  * SCSI_SCAN_TARGET_PRESENT: target responded, but no device is available
75  * on the given LUN.
76  *
77  * SCSI_SCAN_LUN_PRESENT: target responded, and a device is available on a
78  * given LUN.
79  */
80 #define SCSI_SCAN_NO_RESPONSE		0
81 #define SCSI_SCAN_TARGET_PRESENT	1
82 #define SCSI_SCAN_LUN_PRESENT		2
83 
84 static const char *scsi_null_device_strs = "nullnullnullnull";
85 
86 #define MAX_SCSI_LUNS	512
87 
88 static u64 max_scsi_luns = MAX_SCSI_LUNS;
89 
90 module_param_named(max_luns, max_scsi_luns, ullong, S_IRUGO|S_IWUSR);
91 MODULE_PARM_DESC(max_luns,
92 		 "last scsi LUN (should be between 1 and 2^64-1)");
93 
94 #ifdef CONFIG_SCSI_SCAN_ASYNC
95 #define SCSI_SCAN_TYPE_DEFAULT "async"
96 #else
97 #define SCSI_SCAN_TYPE_DEFAULT "sync"
98 #endif
99 
100 static char scsi_scan_type[7] = SCSI_SCAN_TYPE_DEFAULT;
101 
102 module_param_string(scan, scsi_scan_type, sizeof(scsi_scan_type),
103 		    S_IRUGO|S_IWUSR);
104 MODULE_PARM_DESC(scan, "sync, async, manual, or none. "
105 		 "Setting to 'manual' disables automatic scanning, but allows "
106 		 "for manual device scan via the 'scan' sysfs attribute.");
107 
108 static unsigned int scsi_inq_timeout = SCSI_TIMEOUT/HZ + 18;
109 
110 module_param_named(inq_timeout, scsi_inq_timeout, uint, S_IRUGO|S_IWUSR);
111 MODULE_PARM_DESC(inq_timeout,
112 		 "Timeout (in seconds) waiting for devices to answer INQUIRY."
113 		 " Default is 20. Some devices may need more; most need less.");
114 
115 /* This lock protects only this list */
116 static DEFINE_SPINLOCK(async_scan_lock);
117 static LIST_HEAD(scanning_hosts);
118 
119 struct async_scan_data {
120 	struct list_head list;
121 	struct Scsi_Host *shost;
122 	struct completion prev_finished;
123 };
124 
125 /*
126  * scsi_enable_async_suspend - Enable async suspend and resume
127  */
scsi_enable_async_suspend(struct device * dev)128 void scsi_enable_async_suspend(struct device *dev)
129 {
130 	/*
131 	 * If a user has disabled async probing a likely reason is due to a
132 	 * storage enclosure that does not inject staggered spin-ups. For
133 	 * safety, make resume synchronous as well in that case.
134 	 */
135 	if (strncmp(scsi_scan_type, "async", 5) != 0)
136 		return;
137 	/* Enable asynchronous suspend and resume. */
138 	device_enable_async_suspend(dev);
139 }
140 
141 /**
142  * scsi_complete_async_scans - Wait for asynchronous scans to complete
143  *
144  * When this function returns, any host which started scanning before
145  * this function was called will have finished its scan.  Hosts which
146  * started scanning after this function was called may or may not have
147  * finished.
148  */
scsi_complete_async_scans(void)149 int scsi_complete_async_scans(void)
150 {
151 	struct async_scan_data *data;
152 
153 	do {
154 		if (list_empty(&scanning_hosts))
155 			return 0;
156 		/* If we can't get memory immediately, that's OK.  Just
157 		 * sleep a little.  Even if we never get memory, the async
158 		 * scans will finish eventually.
159 		 */
160 		data = kmalloc(sizeof(*data), GFP_KERNEL);
161 		if (!data)
162 			msleep(1);
163 	} while (!data);
164 
165 	data->shost = NULL;
166 	init_completion(&data->prev_finished);
167 
168 	spin_lock(&async_scan_lock);
169 	/* Check that there's still somebody else on the list */
170 	if (list_empty(&scanning_hosts))
171 		goto done;
172 	list_add_tail(&data->list, &scanning_hosts);
173 	spin_unlock(&async_scan_lock);
174 
175 	printk(KERN_INFO "scsi: waiting for bus probes to complete ...\n");
176 	wait_for_completion(&data->prev_finished);
177 
178 	spin_lock(&async_scan_lock);
179 	list_del(&data->list);
180 	if (!list_empty(&scanning_hosts)) {
181 		struct async_scan_data *next = list_entry(scanning_hosts.next,
182 				struct async_scan_data, list);
183 		complete(&next->prev_finished);
184 	}
185  done:
186 	spin_unlock(&async_scan_lock);
187 
188 	kfree(data);
189 	return 0;
190 }
191 
192 /**
193  * scsi_unlock_floptical - unlock device via a special MODE SENSE command
194  * @sdev:	scsi device to send command to
195  * @result:	area to store the result of the MODE SENSE
196  *
197  * Description:
198  *     Send a vendor specific MODE SENSE (not a MODE SELECT) command.
199  *     Called for BLIST_KEY devices.
200  **/
scsi_unlock_floptical(struct scsi_device * sdev,unsigned char * result)201 static void scsi_unlock_floptical(struct scsi_device *sdev,
202 				  unsigned char *result)
203 {
204 	unsigned char scsi_cmd[MAX_COMMAND_SIZE];
205 
206 	sdev_printk(KERN_NOTICE, sdev, "unlocking floptical drive\n");
207 	scsi_cmd[0] = MODE_SENSE;
208 	scsi_cmd[1] = 0;
209 	scsi_cmd[2] = 0x2e;
210 	scsi_cmd[3] = 0;
211 	scsi_cmd[4] = 0x2a;     /* size */
212 	scsi_cmd[5] = 0;
213 	scsi_execute_cmd(sdev, scsi_cmd, REQ_OP_DRV_IN, result, 0x2a,
214 			 SCSI_TIMEOUT, 3, NULL);
215 }
216 
scsi_realloc_sdev_budget_map(struct scsi_device * sdev,unsigned int depth)217 static int scsi_realloc_sdev_budget_map(struct scsi_device *sdev,
218 					unsigned int depth)
219 {
220 	int new_shift = sbitmap_calculate_shift(depth);
221 	bool need_alloc = !sdev->budget_map.map;
222 	bool need_free = false;
223 	int ret;
224 	struct sbitmap sb_backup;
225 
226 	depth = min_t(unsigned int, depth, scsi_device_max_queue_depth(sdev));
227 
228 	/*
229 	 * realloc if new shift is calculated, which is caused by setting
230 	 * up one new default queue depth after calling ->slave_configure
231 	 */
232 	if (!need_alloc && new_shift != sdev->budget_map.shift)
233 		need_alloc = need_free = true;
234 
235 	if (!need_alloc)
236 		return 0;
237 
238 	/*
239 	 * Request queue has to be frozen for reallocating budget map,
240 	 * and here disk isn't added yet, so freezing is pretty fast
241 	 */
242 	if (need_free) {
243 		blk_mq_freeze_queue(sdev->request_queue);
244 		sb_backup = sdev->budget_map;
245 	}
246 	ret = sbitmap_init_node(&sdev->budget_map,
247 				scsi_device_max_queue_depth(sdev),
248 				new_shift, GFP_KERNEL,
249 				sdev->request_queue->node, false, true);
250 	if (!ret)
251 		sbitmap_resize(&sdev->budget_map, depth);
252 
253 	if (need_free) {
254 		if (ret)
255 			sdev->budget_map = sb_backup;
256 		else
257 			sbitmap_free(&sb_backup);
258 		ret = 0;
259 		blk_mq_unfreeze_queue(sdev->request_queue);
260 	}
261 	return ret;
262 }
263 
264 /**
265  * scsi_alloc_sdev - allocate and setup a scsi_Device
266  * @starget: which target to allocate a &scsi_device for
267  * @lun: which lun
268  * @hostdata: usually NULL and set by ->slave_alloc instead
269  *
270  * Description:
271  *     Allocate, initialize for io, and return a pointer to a scsi_Device.
272  *     Stores the @shost, @channel, @id, and @lun in the scsi_Device, and
273  *     adds scsi_Device to the appropriate list.
274  *
275  * Return value:
276  *     scsi_Device pointer, or NULL on failure.
277  **/
scsi_alloc_sdev(struct scsi_target * starget,u64 lun,void * hostdata)278 static struct scsi_device *scsi_alloc_sdev(struct scsi_target *starget,
279 					   u64 lun, void *hostdata)
280 {
281 	unsigned int depth;
282 	struct scsi_device *sdev;
283 	struct request_queue *q;
284 	int display_failure_msg = 1, ret;
285 	struct Scsi_Host *shost = dev_to_shost(starget->dev.parent);
286 
287 	sdev = kzalloc(sizeof(*sdev) + shost->transportt->device_size,
288 		       GFP_KERNEL);
289 	if (!sdev)
290 		goto out;
291 
292 	sdev->vendor = scsi_null_device_strs;
293 	sdev->model = scsi_null_device_strs;
294 	sdev->rev = scsi_null_device_strs;
295 	sdev->host = shost;
296 	sdev->queue_ramp_up_period = SCSI_DEFAULT_RAMP_UP_PERIOD;
297 	sdev->id = starget->id;
298 	sdev->lun = lun;
299 	sdev->channel = starget->channel;
300 	mutex_init(&sdev->state_mutex);
301 	sdev->sdev_state = SDEV_CREATED;
302 	INIT_LIST_HEAD(&sdev->siblings);
303 	INIT_LIST_HEAD(&sdev->same_target_siblings);
304 	INIT_LIST_HEAD(&sdev->starved_entry);
305 	INIT_LIST_HEAD(&sdev->event_list);
306 	spin_lock_init(&sdev->list_lock);
307 	mutex_init(&sdev->inquiry_mutex);
308 	INIT_WORK(&sdev->event_work, scsi_evt_thread);
309 	INIT_WORK(&sdev->requeue_work, scsi_requeue_run_queue);
310 
311 	sdev->sdev_gendev.parent = get_device(&starget->dev);
312 	sdev->sdev_target = starget;
313 
314 	/* usually NULL and set by ->slave_alloc instead */
315 	sdev->hostdata = hostdata;
316 
317 	/* if the device needs this changing, it may do so in the
318 	 * slave_configure function */
319 	sdev->max_device_blocked = SCSI_DEFAULT_DEVICE_BLOCKED;
320 
321 	/*
322 	 * Some low level driver could use device->type
323 	 */
324 	sdev->type = -1;
325 
326 	/*
327 	 * Assume that the device will have handshaking problems,
328 	 * and then fix this field later if it turns out it
329 	 * doesn't
330 	 */
331 	sdev->borken = 1;
332 
333 	sdev->sg_reserved_size = INT_MAX;
334 
335 	q = blk_mq_init_queue(&sdev->host->tag_set);
336 	if (IS_ERR(q)) {
337 		/* release fn is set up in scsi_sysfs_device_initialise, so
338 		 * have to free and put manually here */
339 		put_device(&starget->dev);
340 		kfree(sdev);
341 		goto out;
342 	}
343 	kref_get(&sdev->host->tagset_refcnt);
344 	sdev->request_queue = q;
345 	q->queuedata = sdev;
346 	__scsi_init_queue(sdev->host, q);
347 
348 	depth = sdev->host->cmd_per_lun ?: 1;
349 
350 	/*
351 	 * Use .can_queue as budget map's depth because we have to
352 	 * support adjusting queue depth from sysfs. Meantime use
353 	 * default device queue depth to figure out sbitmap shift
354 	 * since we use this queue depth most of times.
355 	 */
356 	if (scsi_realloc_sdev_budget_map(sdev, depth)) {
357 		put_device(&starget->dev);
358 		kfree(sdev);
359 		goto out;
360 	}
361 
362 	scsi_change_queue_depth(sdev, depth);
363 
364 	scsi_sysfs_device_initialize(sdev);
365 
366 	if (shost->hostt->slave_alloc) {
367 		ret = shost->hostt->slave_alloc(sdev);
368 		if (ret) {
369 			/*
370 			 * if LLDD reports slave not present, don't clutter
371 			 * console with alloc failure messages
372 			 */
373 			if (ret == -ENXIO)
374 				display_failure_msg = 0;
375 			goto out_device_destroy;
376 		}
377 	}
378 
379 	return sdev;
380 
381 out_device_destroy:
382 	__scsi_remove_device(sdev);
383 out:
384 	if (display_failure_msg)
385 		printk(ALLOC_FAILURE_MSG, __func__);
386 	return NULL;
387 }
388 
scsi_target_destroy(struct scsi_target * starget)389 static void scsi_target_destroy(struct scsi_target *starget)
390 {
391 	struct device *dev = &starget->dev;
392 	struct Scsi_Host *shost = dev_to_shost(dev->parent);
393 	unsigned long flags;
394 
395 	BUG_ON(starget->state == STARGET_DEL);
396 	starget->state = STARGET_DEL;
397 	transport_destroy_device(dev);
398 	spin_lock_irqsave(shost->host_lock, flags);
399 	if (shost->hostt->target_destroy)
400 		shost->hostt->target_destroy(starget);
401 	list_del_init(&starget->siblings);
402 	spin_unlock_irqrestore(shost->host_lock, flags);
403 	put_device(dev);
404 }
405 
scsi_target_dev_release(struct device * dev)406 static void scsi_target_dev_release(struct device *dev)
407 {
408 	struct device *parent = dev->parent;
409 	struct scsi_target *starget = to_scsi_target(dev);
410 
411 	kfree(starget);
412 	put_device(parent);
413 }
414 
415 static struct device_type scsi_target_type = {
416 	.name =		"scsi_target",
417 	.release =	scsi_target_dev_release,
418 };
419 
scsi_is_target_device(const struct device * dev)420 int scsi_is_target_device(const struct device *dev)
421 {
422 	return dev->type == &scsi_target_type;
423 }
424 EXPORT_SYMBOL(scsi_is_target_device);
425 
__scsi_find_target(struct device * parent,int channel,uint id)426 static struct scsi_target *__scsi_find_target(struct device *parent,
427 					      int channel, uint id)
428 {
429 	struct scsi_target *starget, *found_starget = NULL;
430 	struct Scsi_Host *shost = dev_to_shost(parent);
431 	/*
432 	 * Search for an existing target for this sdev.
433 	 */
434 	list_for_each_entry(starget, &shost->__targets, siblings) {
435 		if (starget->id == id &&
436 		    starget->channel == channel) {
437 			found_starget = starget;
438 			break;
439 		}
440 	}
441 	if (found_starget)
442 		get_device(&found_starget->dev);
443 
444 	return found_starget;
445 }
446 
447 /**
448  * scsi_target_reap_ref_release - remove target from visibility
449  * @kref: the reap_ref in the target being released
450  *
451  * Called on last put of reap_ref, which is the indication that no device
452  * under this target is visible anymore, so render the target invisible in
453  * sysfs.  Note: we have to be in user context here because the target reaps
454  * should be done in places where the scsi device visibility is being removed.
455  */
scsi_target_reap_ref_release(struct kref * kref)456 static void scsi_target_reap_ref_release(struct kref *kref)
457 {
458 	struct scsi_target *starget
459 		= container_of(kref, struct scsi_target, reap_ref);
460 
461 	/*
462 	 * if we get here and the target is still in a CREATED state that
463 	 * means it was allocated but never made visible (because a scan
464 	 * turned up no LUNs), so don't call device_del() on it.
465 	 */
466 	if ((starget->state != STARGET_CREATED) &&
467 	    (starget->state != STARGET_CREATED_REMOVE)) {
468 		transport_remove_device(&starget->dev);
469 		device_del(&starget->dev);
470 	}
471 	scsi_target_destroy(starget);
472 }
473 
scsi_target_reap_ref_put(struct scsi_target * starget)474 static void scsi_target_reap_ref_put(struct scsi_target *starget)
475 {
476 	kref_put(&starget->reap_ref, scsi_target_reap_ref_release);
477 }
478 
479 /**
480  * scsi_alloc_target - allocate a new or find an existing target
481  * @parent:	parent of the target (need not be a scsi host)
482  * @channel:	target channel number (zero if no channels)
483  * @id:		target id number
484  *
485  * Return an existing target if one exists, provided it hasn't already
486  * gone into STARGET_DEL state, otherwise allocate a new target.
487  *
488  * The target is returned with an incremented reference, so the caller
489  * is responsible for both reaping and doing a last put
490  */
scsi_alloc_target(struct device * parent,int channel,uint id)491 static struct scsi_target *scsi_alloc_target(struct device *parent,
492 					     int channel, uint id)
493 {
494 	struct Scsi_Host *shost = dev_to_shost(parent);
495 	struct device *dev = NULL;
496 	unsigned long flags;
497 	const int size = sizeof(struct scsi_target)
498 		+ shost->transportt->target_size;
499 	struct scsi_target *starget;
500 	struct scsi_target *found_target;
501 	int error, ref_got;
502 
503 	starget = kzalloc(size, GFP_KERNEL);
504 	if (!starget) {
505 		printk(KERN_ERR "%s: allocation failure\n", __func__);
506 		return NULL;
507 	}
508 	dev = &starget->dev;
509 	device_initialize(dev);
510 	kref_init(&starget->reap_ref);
511 	dev->parent = get_device(parent);
512 	dev_set_name(dev, "target%d:%d:%d", shost->host_no, channel, id);
513 	dev->bus = &scsi_bus_type;
514 	dev->type = &scsi_target_type;
515 	scsi_enable_async_suspend(dev);
516 	starget->id = id;
517 	starget->channel = channel;
518 	starget->can_queue = 0;
519 	INIT_LIST_HEAD(&starget->siblings);
520 	INIT_LIST_HEAD(&starget->devices);
521 	starget->state = STARGET_CREATED;
522 	starget->scsi_level = SCSI_2;
523 	starget->max_target_blocked = SCSI_DEFAULT_TARGET_BLOCKED;
524  retry:
525 	spin_lock_irqsave(shost->host_lock, flags);
526 
527 	found_target = __scsi_find_target(parent, channel, id);
528 	if (found_target)
529 		goto found;
530 
531 	list_add_tail(&starget->siblings, &shost->__targets);
532 	spin_unlock_irqrestore(shost->host_lock, flags);
533 	/* allocate and add */
534 	transport_setup_device(dev);
535 	if (shost->hostt->target_alloc) {
536 		error = shost->hostt->target_alloc(starget);
537 
538 		if(error) {
539 			if (error != -ENXIO)
540 				dev_err(dev, "target allocation failed, error %d\n", error);
541 			/* don't want scsi_target_reap to do the final
542 			 * put because it will be under the host lock */
543 			scsi_target_destroy(starget);
544 			return NULL;
545 		}
546 	}
547 	get_device(dev);
548 
549 	return starget;
550 
551  found:
552 	/*
553 	 * release routine already fired if kref is zero, so if we can still
554 	 * take the reference, the target must be alive.  If we can't, it must
555 	 * be dying and we need to wait for a new target
556 	 */
557 	ref_got = kref_get_unless_zero(&found_target->reap_ref);
558 
559 	spin_unlock_irqrestore(shost->host_lock, flags);
560 	if (ref_got) {
561 		put_device(dev);
562 		return found_target;
563 	}
564 	/*
565 	 * Unfortunately, we found a dying target; need to wait until it's
566 	 * dead before we can get a new one.  There is an anomaly here.  We
567 	 * *should* call scsi_target_reap() to balance the kref_get() of the
568 	 * reap_ref above.  However, since the target being released, it's
569 	 * already invisible and the reap_ref is irrelevant.  If we call
570 	 * scsi_target_reap() we might spuriously do another device_del() on
571 	 * an already invisible target.
572 	 */
573 	put_device(&found_target->dev);
574 	/*
575 	 * length of time is irrelevant here, we just want to yield the CPU
576 	 * for a tick to avoid busy waiting for the target to die.
577 	 */
578 	msleep(1);
579 	goto retry;
580 }
581 
582 /**
583  * scsi_target_reap - check to see if target is in use and destroy if not
584  * @starget: target to be checked
585  *
586  * This is used after removing a LUN or doing a last put of the target
587  * it checks atomically that nothing is using the target and removes
588  * it if so.
589  */
scsi_target_reap(struct scsi_target * starget)590 void scsi_target_reap(struct scsi_target *starget)
591 {
592 	/*
593 	 * serious problem if this triggers: STARGET_DEL is only set in the if
594 	 * the reap_ref drops to zero, so we're trying to do another final put
595 	 * on an already released kref
596 	 */
597 	BUG_ON(starget->state == STARGET_DEL);
598 	scsi_target_reap_ref_put(starget);
599 }
600 
601 /**
602  * scsi_sanitize_inquiry_string - remove non-graphical chars from an
603  *                                INQUIRY result string
604  * @s: INQUIRY result string to sanitize
605  * @len: length of the string
606  *
607  * Description:
608  *	The SCSI spec says that INQUIRY vendor, product, and revision
609  *	strings must consist entirely of graphic ASCII characters,
610  *	padded on the right with spaces.  Since not all devices obey
611  *	this rule, we will replace non-graphic or non-ASCII characters
612  *	with spaces.  Exception: a NUL character is interpreted as a
613  *	string terminator, so all the following characters are set to
614  *	spaces.
615  **/
scsi_sanitize_inquiry_string(unsigned char * s,int len)616 void scsi_sanitize_inquiry_string(unsigned char *s, int len)
617 {
618 	int terminated = 0;
619 
620 	for (; len > 0; (--len, ++s)) {
621 		if (*s == 0)
622 			terminated = 1;
623 		if (terminated || *s < 0x20 || *s > 0x7e)
624 			*s = ' ';
625 	}
626 }
627 EXPORT_SYMBOL(scsi_sanitize_inquiry_string);
628 
629 /**
630  * scsi_probe_lun - probe a single LUN using a SCSI INQUIRY
631  * @sdev:	scsi_device to probe
632  * @inq_result:	area to store the INQUIRY result
633  * @result_len: len of inq_result
634  * @bflags:	store any bflags found here
635  *
636  * Description:
637  *     Probe the lun associated with @req using a standard SCSI INQUIRY;
638  *
639  *     If the INQUIRY is successful, zero is returned and the
640  *     INQUIRY data is in @inq_result; the scsi_level and INQUIRY length
641  *     are copied to the scsi_device any flags value is stored in *@bflags.
642  **/
scsi_probe_lun(struct scsi_device * sdev,unsigned char * inq_result,int result_len,blist_flags_t * bflags)643 static int scsi_probe_lun(struct scsi_device *sdev, unsigned char *inq_result,
644 			  int result_len, blist_flags_t *bflags)
645 {
646 	unsigned char scsi_cmd[MAX_COMMAND_SIZE];
647 	int first_inquiry_len, try_inquiry_len, next_inquiry_len;
648 	int response_len = 0;
649 	int pass, count, result, resid;
650 	struct scsi_sense_hdr sshdr;
651 	const struct scsi_exec_args exec_args = {
652 		.sshdr = &sshdr,
653 		.resid = &resid,
654 	};
655 
656 	*bflags = 0;
657 
658 	/* Perform up to 3 passes.  The first pass uses a conservative
659 	 * transfer length of 36 unless sdev->inquiry_len specifies a
660 	 * different value. */
661 	first_inquiry_len = sdev->inquiry_len ? sdev->inquiry_len : 36;
662 	try_inquiry_len = first_inquiry_len;
663 	pass = 1;
664 
665  next_pass:
666 	SCSI_LOG_SCAN_BUS(3, sdev_printk(KERN_INFO, sdev,
667 				"scsi scan: INQUIRY pass %d length %d\n",
668 				pass, try_inquiry_len));
669 
670 	/* Each pass gets up to three chances to ignore Unit Attention */
671 	for (count = 0; count < 3; ++count) {
672 		memset(scsi_cmd, 0, 6);
673 		scsi_cmd[0] = INQUIRY;
674 		scsi_cmd[4] = (unsigned char) try_inquiry_len;
675 
676 		memset(inq_result, 0, try_inquiry_len);
677 
678 		result = scsi_execute_cmd(sdev,  scsi_cmd, REQ_OP_DRV_IN,
679 					  inq_result, try_inquiry_len,
680 					  HZ / 2 + HZ * scsi_inq_timeout, 3,
681 					  &exec_args);
682 
683 		SCSI_LOG_SCAN_BUS(3, sdev_printk(KERN_INFO, sdev,
684 				"scsi scan: INQUIRY %s with code 0x%x\n",
685 				result ? "failed" : "successful", result));
686 
687 		if (result > 0) {
688 			/*
689 			 * not-ready to ready transition [asc/ascq=0x28/0x0]
690 			 * or power-on, reset [asc/ascq=0x29/0x0], continue.
691 			 * INQUIRY should not yield UNIT_ATTENTION
692 			 * but many buggy devices do so anyway.
693 			 */
694 			if (scsi_status_is_check_condition(result) &&
695 			    scsi_sense_valid(&sshdr)) {
696 				if ((sshdr.sense_key == UNIT_ATTENTION) &&
697 				    ((sshdr.asc == 0x28) ||
698 				     (sshdr.asc == 0x29)) &&
699 				    (sshdr.ascq == 0))
700 					continue;
701 			}
702 		} else if (result == 0) {
703 			/*
704 			 * if nothing was transferred, we try
705 			 * again. It's a workaround for some USB
706 			 * devices.
707 			 */
708 			if (resid == try_inquiry_len)
709 				continue;
710 		}
711 		break;
712 	}
713 
714 	if (result == 0) {
715 		scsi_sanitize_inquiry_string(&inq_result[8], 8);
716 		scsi_sanitize_inquiry_string(&inq_result[16], 16);
717 		scsi_sanitize_inquiry_string(&inq_result[32], 4);
718 
719 		response_len = inq_result[4] + 5;
720 		if (response_len > 255)
721 			response_len = first_inquiry_len;	/* sanity */
722 
723 		/*
724 		 * Get any flags for this device.
725 		 *
726 		 * XXX add a bflags to scsi_device, and replace the
727 		 * corresponding bit fields in scsi_device, so bflags
728 		 * need not be passed as an argument.
729 		 */
730 		*bflags = scsi_get_device_flags(sdev, &inq_result[8],
731 				&inq_result[16]);
732 
733 		/* When the first pass succeeds we gain information about
734 		 * what larger transfer lengths might work. */
735 		if (pass == 1) {
736 			if (BLIST_INQUIRY_36 & *bflags)
737 				next_inquiry_len = 36;
738 			/*
739 			 * LLD specified a maximum sdev->inquiry_len
740 			 * but device claims it has more data. Capping
741 			 * the length only makes sense for legacy
742 			 * devices. If a device supports SPC-4 (2014)
743 			 * or newer, assume that it is safe to ask for
744 			 * as much as the device says it supports.
745 			 */
746 			else if (sdev->inquiry_len &&
747 				 response_len > sdev->inquiry_len &&
748 				 (inq_result[2] & 0x7) < 6) /* SPC-4 */
749 				next_inquiry_len = sdev->inquiry_len;
750 			else
751 				next_inquiry_len = response_len;
752 
753 			/* If more data is available perform the second pass */
754 			if (next_inquiry_len > try_inquiry_len) {
755 				try_inquiry_len = next_inquiry_len;
756 				pass = 2;
757 				goto next_pass;
758 			}
759 		}
760 
761 	} else if (pass == 2) {
762 		sdev_printk(KERN_INFO, sdev,
763 			    "scsi scan: %d byte inquiry failed.  "
764 			    "Consider BLIST_INQUIRY_36 for this device\n",
765 			    try_inquiry_len);
766 
767 		/* If this pass failed, the third pass goes back and transfers
768 		 * the same amount as we successfully got in the first pass. */
769 		try_inquiry_len = first_inquiry_len;
770 		pass = 3;
771 		goto next_pass;
772 	}
773 
774 	/* If the last transfer attempt got an error, assume the
775 	 * peripheral doesn't exist or is dead. */
776 	if (result)
777 		return -EIO;
778 
779 	/* Don't report any more data than the device says is valid */
780 	sdev->inquiry_len = min(try_inquiry_len, response_len);
781 
782 	/*
783 	 * XXX Abort if the response length is less than 36? If less than
784 	 * 32, the lookup of the device flags (above) could be invalid,
785 	 * and it would be possible to take an incorrect action - we do
786 	 * not want to hang because of a short INQUIRY. On the flip side,
787 	 * if the device is spun down or becoming ready (and so it gives a
788 	 * short INQUIRY), an abort here prevents any further use of the
789 	 * device, including spin up.
790 	 *
791 	 * On the whole, the best approach seems to be to assume the first
792 	 * 36 bytes are valid no matter what the device says.  That's
793 	 * better than copying < 36 bytes to the inquiry-result buffer
794 	 * and displaying garbage for the Vendor, Product, or Revision
795 	 * strings.
796 	 */
797 	if (sdev->inquiry_len < 36) {
798 		if (!sdev->host->short_inquiry) {
799 			shost_printk(KERN_INFO, sdev->host,
800 				    "scsi scan: INQUIRY result too short (%d),"
801 				    " using 36\n", sdev->inquiry_len);
802 			sdev->host->short_inquiry = 1;
803 		}
804 		sdev->inquiry_len = 36;
805 	}
806 
807 	/*
808 	 * Related to the above issue:
809 	 *
810 	 * XXX Devices (disk or all?) should be sent a TEST UNIT READY,
811 	 * and if not ready, sent a START_STOP to start (maybe spin up) and
812 	 * then send the INQUIRY again, since the INQUIRY can change after
813 	 * a device is initialized.
814 	 *
815 	 * Ideally, start a device if explicitly asked to do so.  This
816 	 * assumes that a device is spun up on power on, spun down on
817 	 * request, and then spun up on request.
818 	 */
819 
820 	/*
821 	 * The scanning code needs to know the scsi_level, even if no
822 	 * device is attached at LUN 0 (SCSI_SCAN_TARGET_PRESENT) so
823 	 * non-zero LUNs can be scanned.
824 	 */
825 	sdev->scsi_level = inq_result[2] & 0x0f;
826 	if (sdev->scsi_level >= 2 ||
827 	    (sdev->scsi_level == 1 && (inq_result[3] & 0x0f) == 1))
828 		sdev->scsi_level++;
829 	sdev->sdev_target->scsi_level = sdev->scsi_level;
830 
831 	/*
832 	 * If SCSI-2 or lower, and if the transport requires it,
833 	 * store the LUN value in CDB[1].
834 	 */
835 	sdev->lun_in_cdb = 0;
836 	if (sdev->scsi_level <= SCSI_2 &&
837 	    sdev->scsi_level != SCSI_UNKNOWN &&
838 	    !sdev->host->no_scsi2_lun_in_cdb)
839 		sdev->lun_in_cdb = 1;
840 
841 	return 0;
842 }
843 
844 /**
845  * scsi_add_lun - allocate and fully initialze a scsi_device
846  * @sdev:	holds information to be stored in the new scsi_device
847  * @inq_result:	holds the result of a previous INQUIRY to the LUN
848  * @bflags:	black/white list flag
849  * @async:	1 if this device is being scanned asynchronously
850  *
851  * Description:
852  *     Initialize the scsi_device @sdev.  Optionally set fields based
853  *     on values in *@bflags.
854  *
855  * Return:
856  *     SCSI_SCAN_NO_RESPONSE: could not allocate or setup a scsi_device
857  *     SCSI_SCAN_LUN_PRESENT: a new scsi_device was allocated and initialized
858  **/
scsi_add_lun(struct scsi_device * sdev,unsigned char * inq_result,blist_flags_t * bflags,int async)859 static int scsi_add_lun(struct scsi_device *sdev, unsigned char *inq_result,
860 		blist_flags_t *bflags, int async)
861 {
862 	int ret;
863 
864 	/*
865 	 * XXX do not save the inquiry, since it can change underneath us,
866 	 * save just vendor/model/rev.
867 	 *
868 	 * Rather than save it and have an ioctl that retrieves the saved
869 	 * value, have an ioctl that executes the same INQUIRY code used
870 	 * in scsi_probe_lun, let user level programs doing INQUIRY
871 	 * scanning run at their own risk, or supply a user level program
872 	 * that can correctly scan.
873 	 */
874 
875 	/*
876 	 * Copy at least 36 bytes of INQUIRY data, so that we don't
877 	 * dereference unallocated memory when accessing the Vendor,
878 	 * Product, and Revision strings.  Badly behaved devices may set
879 	 * the INQUIRY Additional Length byte to a small value, indicating
880 	 * these strings are invalid, but often they contain plausible data
881 	 * nonetheless.  It doesn't matter if the device sent < 36 bytes
882 	 * total, since scsi_probe_lun() initializes inq_result with 0s.
883 	 */
884 	sdev->inquiry = kmemdup(inq_result,
885 				max_t(size_t, sdev->inquiry_len, 36),
886 				GFP_KERNEL);
887 	if (sdev->inquiry == NULL)
888 		return SCSI_SCAN_NO_RESPONSE;
889 
890 	sdev->vendor = (char *) (sdev->inquiry + 8);
891 	sdev->model = (char *) (sdev->inquiry + 16);
892 	sdev->rev = (char *) (sdev->inquiry + 32);
893 
894 	if (strncmp(sdev->vendor, "ATA     ", 8) == 0) {
895 		/*
896 		 * sata emulation layer device.  This is a hack to work around
897 		 * the SATL power management specifications which state that
898 		 * when the SATL detects the device has gone into standby
899 		 * mode, it shall respond with NOT READY.
900 		 */
901 		sdev->allow_restart = 1;
902 	}
903 
904 	if (*bflags & BLIST_ISROM) {
905 		sdev->type = TYPE_ROM;
906 		sdev->removable = 1;
907 	} else {
908 		sdev->type = (inq_result[0] & 0x1f);
909 		sdev->removable = (inq_result[1] & 0x80) >> 7;
910 
911 		/*
912 		 * some devices may respond with wrong type for
913 		 * well-known logical units. Force well-known type
914 		 * to enumerate them correctly.
915 		 */
916 		if (scsi_is_wlun(sdev->lun) && sdev->type != TYPE_WLUN) {
917 			sdev_printk(KERN_WARNING, sdev,
918 				"%s: correcting incorrect peripheral device type 0x%x for W-LUN 0x%16xhN\n",
919 				__func__, sdev->type, (unsigned int)sdev->lun);
920 			sdev->type = TYPE_WLUN;
921 		}
922 
923 	}
924 
925 	if (sdev->type == TYPE_RBC || sdev->type == TYPE_ROM) {
926 		/* RBC and MMC devices can return SCSI-3 compliance and yet
927 		 * still not support REPORT LUNS, so make them act as
928 		 * BLIST_NOREPORTLUN unless BLIST_REPORTLUN2 is
929 		 * specifically set */
930 		if ((*bflags & BLIST_REPORTLUN2) == 0)
931 			*bflags |= BLIST_NOREPORTLUN;
932 	}
933 
934 	/*
935 	 * For a peripheral qualifier (PQ) value of 1 (001b), the SCSI
936 	 * spec says: The device server is capable of supporting the
937 	 * specified peripheral device type on this logical unit. However,
938 	 * the physical device is not currently connected to this logical
939 	 * unit.
940 	 *
941 	 * The above is vague, as it implies that we could treat 001 and
942 	 * 011 the same. Stay compatible with previous code, and create a
943 	 * scsi_device for a PQ of 1
944 	 *
945 	 * Don't set the device offline here; rather let the upper
946 	 * level drivers eval the PQ to decide whether they should
947 	 * attach. So remove ((inq_result[0] >> 5) & 7) == 1 check.
948 	 */
949 
950 	sdev->inq_periph_qual = (inq_result[0] >> 5) & 7;
951 	sdev->lockable = sdev->removable;
952 	sdev->soft_reset = (inq_result[7] & 1) && ((inq_result[3] & 7) == 2);
953 
954 	if (sdev->scsi_level >= SCSI_3 ||
955 			(sdev->inquiry_len > 56 && inq_result[56] & 0x04))
956 		sdev->ppr = 1;
957 	if (inq_result[7] & 0x60)
958 		sdev->wdtr = 1;
959 	if (inq_result[7] & 0x10)
960 		sdev->sdtr = 1;
961 
962 	sdev_printk(KERN_NOTICE, sdev, "%s %.8s %.16s %.4s PQ: %d "
963 			"ANSI: %d%s\n", scsi_device_type(sdev->type),
964 			sdev->vendor, sdev->model, sdev->rev,
965 			sdev->inq_periph_qual, inq_result[2] & 0x07,
966 			(inq_result[3] & 0x0f) == 1 ? " CCS" : "");
967 
968 	if ((sdev->scsi_level >= SCSI_2) && (inq_result[7] & 2) &&
969 	    !(*bflags & BLIST_NOTQ)) {
970 		sdev->tagged_supported = 1;
971 		sdev->simple_tags = 1;
972 	}
973 
974 	/*
975 	 * Some devices (Texel CD ROM drives) have handshaking problems
976 	 * when used with the Seagate controllers. borken is initialized
977 	 * to 1, and then set it to 0 here.
978 	 */
979 	if ((*bflags & BLIST_BORKEN) == 0)
980 		sdev->borken = 0;
981 
982 	if (*bflags & BLIST_NO_ULD_ATTACH)
983 		sdev->no_uld_attach = 1;
984 
985 	/*
986 	 * Apparently some really broken devices (contrary to the SCSI
987 	 * standards) need to be selected without asserting ATN
988 	 */
989 	if (*bflags & BLIST_SELECT_NO_ATN)
990 		sdev->select_no_atn = 1;
991 
992 	/*
993 	 * Maximum 512 sector transfer length
994 	 * broken RA4x00 Compaq Disk Array
995 	 */
996 	if (*bflags & BLIST_MAX_512)
997 		blk_queue_max_hw_sectors(sdev->request_queue, 512);
998 	/*
999 	 * Max 1024 sector transfer length for targets that report incorrect
1000 	 * max/optimal lengths and relied on the old block layer safe default
1001 	 */
1002 	else if (*bflags & BLIST_MAX_1024)
1003 		blk_queue_max_hw_sectors(sdev->request_queue, 1024);
1004 
1005 	/*
1006 	 * Some devices may not want to have a start command automatically
1007 	 * issued when a device is added.
1008 	 */
1009 	if (*bflags & BLIST_NOSTARTONADD)
1010 		sdev->no_start_on_add = 1;
1011 
1012 	if (*bflags & BLIST_SINGLELUN)
1013 		scsi_target(sdev)->single_lun = 1;
1014 
1015 	sdev->use_10_for_rw = 1;
1016 
1017 	/* some devices don't like REPORT SUPPORTED OPERATION CODES
1018 	 * and will simply timeout causing sd_mod init to take a very
1019 	 * very long time */
1020 	if (*bflags & BLIST_NO_RSOC)
1021 		sdev->no_report_opcodes = 1;
1022 
1023 	/* set the device running here so that slave configure
1024 	 * may do I/O */
1025 	mutex_lock(&sdev->state_mutex);
1026 	ret = scsi_device_set_state(sdev, SDEV_RUNNING);
1027 	if (ret)
1028 		ret = scsi_device_set_state(sdev, SDEV_BLOCK);
1029 	mutex_unlock(&sdev->state_mutex);
1030 
1031 	if (ret) {
1032 		sdev_printk(KERN_ERR, sdev,
1033 			    "in wrong state %s to complete scan\n",
1034 			    scsi_device_state_name(sdev->sdev_state));
1035 		return SCSI_SCAN_NO_RESPONSE;
1036 	}
1037 
1038 	if (*bflags & BLIST_NOT_LOCKABLE)
1039 		sdev->lockable = 0;
1040 
1041 	if (*bflags & BLIST_RETRY_HWERROR)
1042 		sdev->retry_hwerror = 1;
1043 
1044 	if (*bflags & BLIST_NO_DIF)
1045 		sdev->no_dif = 1;
1046 
1047 	if (*bflags & BLIST_UNMAP_LIMIT_WS)
1048 		sdev->unmap_limit_for_ws = 1;
1049 
1050 	if (*bflags & BLIST_IGN_MEDIA_CHANGE)
1051 		sdev->ignore_media_change = 1;
1052 
1053 	sdev->eh_timeout = SCSI_DEFAULT_EH_TIMEOUT;
1054 
1055 	if (*bflags & BLIST_TRY_VPD_PAGES)
1056 		sdev->try_vpd_pages = 1;
1057 	else if (*bflags & BLIST_SKIP_VPD_PAGES)
1058 		sdev->skip_vpd_pages = 1;
1059 
1060 	if (*bflags & BLIST_NO_VPD_SIZE)
1061 		sdev->no_vpd_size = 1;
1062 
1063 	transport_configure_device(&sdev->sdev_gendev);
1064 
1065 	if (sdev->host->hostt->slave_configure) {
1066 		ret = sdev->host->hostt->slave_configure(sdev);
1067 		if (ret) {
1068 			/*
1069 			 * if LLDD reports slave not present, don't clutter
1070 			 * console with alloc failure messages
1071 			 */
1072 			if (ret != -ENXIO) {
1073 				sdev_printk(KERN_ERR, sdev,
1074 					"failed to configure device\n");
1075 			}
1076 			return SCSI_SCAN_NO_RESPONSE;
1077 		}
1078 
1079 		/*
1080 		 * The queue_depth is often changed in ->slave_configure.
1081 		 * Set up budget map again since memory consumption of
1082 		 * the map depends on actual queue depth.
1083 		 */
1084 		scsi_realloc_sdev_budget_map(sdev, sdev->queue_depth);
1085 	}
1086 
1087 	if (sdev->scsi_level >= SCSI_3)
1088 		scsi_attach_vpd(sdev);
1089 
1090 	scsi_cdl_check(sdev);
1091 
1092 	sdev->max_queue_depth = sdev->queue_depth;
1093 	WARN_ON_ONCE(sdev->max_queue_depth > sdev->budget_map.depth);
1094 	sdev->sdev_bflags = *bflags;
1095 
1096 	/*
1097 	 * Ok, the device is now all set up, we can
1098 	 * register it and tell the rest of the kernel
1099 	 * about it.
1100 	 */
1101 	if (!async && scsi_sysfs_add_sdev(sdev) != 0)
1102 		return SCSI_SCAN_NO_RESPONSE;
1103 
1104 	return SCSI_SCAN_LUN_PRESENT;
1105 }
1106 
1107 #ifdef CONFIG_SCSI_LOGGING
1108 /**
1109  * scsi_inq_str - print INQUIRY data from min to max index, strip trailing whitespace
1110  * @buf:   Output buffer with at least end-first+1 bytes of space
1111  * @inq:   Inquiry buffer (input)
1112  * @first: Offset of string into inq
1113  * @end:   Index after last character in inq
1114  */
scsi_inq_str(unsigned char * buf,unsigned char * inq,unsigned first,unsigned end)1115 static unsigned char *scsi_inq_str(unsigned char *buf, unsigned char *inq,
1116 				   unsigned first, unsigned end)
1117 {
1118 	unsigned term = 0, idx;
1119 
1120 	for (idx = 0; idx + first < end && idx + first < inq[4] + 5; idx++) {
1121 		if (inq[idx+first] > ' ') {
1122 			buf[idx] = inq[idx+first];
1123 			term = idx+1;
1124 		} else {
1125 			buf[idx] = ' ';
1126 		}
1127 	}
1128 	buf[term] = 0;
1129 	return buf;
1130 }
1131 #endif
1132 
1133 /**
1134  * scsi_probe_and_add_lun - probe a LUN, if a LUN is found add it
1135  * @starget:	pointer to target device structure
1136  * @lun:	LUN of target device
1137  * @bflagsp:	store bflags here if not NULL
1138  * @sdevp:	probe the LUN corresponding to this scsi_device
1139  * @rescan:     if not equal to SCSI_SCAN_INITIAL skip some code only
1140  *              needed on first scan
1141  * @hostdata:	passed to scsi_alloc_sdev()
1142  *
1143  * Description:
1144  *     Call scsi_probe_lun, if a LUN with an attached device is found,
1145  *     allocate and set it up by calling scsi_add_lun.
1146  *
1147  * Return:
1148  *
1149  *   - SCSI_SCAN_NO_RESPONSE: could not allocate or setup a scsi_device
1150  *   - SCSI_SCAN_TARGET_PRESENT: target responded, but no device is
1151  *         attached at the LUN
1152  *   - SCSI_SCAN_LUN_PRESENT: a new scsi_device was allocated and initialized
1153  **/
scsi_probe_and_add_lun(struct scsi_target * starget,u64 lun,blist_flags_t * bflagsp,struct scsi_device ** sdevp,enum scsi_scan_mode rescan,void * hostdata)1154 static int scsi_probe_and_add_lun(struct scsi_target *starget,
1155 				  u64 lun, blist_flags_t *bflagsp,
1156 				  struct scsi_device **sdevp,
1157 				  enum scsi_scan_mode rescan,
1158 				  void *hostdata)
1159 {
1160 	struct scsi_device *sdev;
1161 	unsigned char *result;
1162 	blist_flags_t bflags;
1163 	int res = SCSI_SCAN_NO_RESPONSE, result_len = 256;
1164 	struct Scsi_Host *shost = dev_to_shost(starget->dev.parent);
1165 
1166 	/*
1167 	 * The rescan flag is used as an optimization, the first scan of a
1168 	 * host adapter calls into here with rescan == 0.
1169 	 */
1170 	sdev = scsi_device_lookup_by_target(starget, lun);
1171 	if (sdev) {
1172 		if (rescan != SCSI_SCAN_INITIAL || !scsi_device_created(sdev)) {
1173 			SCSI_LOG_SCAN_BUS(3, sdev_printk(KERN_INFO, sdev,
1174 				"scsi scan: device exists on %s\n",
1175 				dev_name(&sdev->sdev_gendev)));
1176 			if (sdevp)
1177 				*sdevp = sdev;
1178 			else
1179 				scsi_device_put(sdev);
1180 
1181 			if (bflagsp)
1182 				*bflagsp = scsi_get_device_flags(sdev,
1183 								 sdev->vendor,
1184 								 sdev->model);
1185 			return SCSI_SCAN_LUN_PRESENT;
1186 		}
1187 		scsi_device_put(sdev);
1188 	} else
1189 		sdev = scsi_alloc_sdev(starget, lun, hostdata);
1190 	if (!sdev)
1191 		goto out;
1192 
1193 	result = kmalloc(result_len, GFP_KERNEL);
1194 	if (!result)
1195 		goto out_free_sdev;
1196 
1197 	if (scsi_probe_lun(sdev, result, result_len, &bflags))
1198 		goto out_free_result;
1199 
1200 	if (bflagsp)
1201 		*bflagsp = bflags;
1202 	/*
1203 	 * result contains valid SCSI INQUIRY data.
1204 	 */
1205 	if ((result[0] >> 5) == 3) {
1206 		/*
1207 		 * For a Peripheral qualifier 3 (011b), the SCSI
1208 		 * spec says: The device server is not capable of
1209 		 * supporting a physical device on this logical
1210 		 * unit.
1211 		 *
1212 		 * For disks, this implies that there is no
1213 		 * logical disk configured at sdev->lun, but there
1214 		 * is a target id responding.
1215 		 */
1216 		SCSI_LOG_SCAN_BUS(2, sdev_printk(KERN_INFO, sdev, "scsi scan:"
1217 				   " peripheral qualifier of 3, device not"
1218 				   " added\n"))
1219 		if (lun == 0) {
1220 			SCSI_LOG_SCAN_BUS(1, {
1221 				unsigned char vend[9];
1222 				unsigned char mod[17];
1223 
1224 				sdev_printk(KERN_INFO, sdev,
1225 					"scsi scan: consider passing scsi_mod."
1226 					"dev_flags=%s:%s:0x240 or 0x1000240\n",
1227 					scsi_inq_str(vend, result, 8, 16),
1228 					scsi_inq_str(mod, result, 16, 32));
1229 			});
1230 
1231 		}
1232 
1233 		res = SCSI_SCAN_TARGET_PRESENT;
1234 		goto out_free_result;
1235 	}
1236 
1237 	/*
1238 	 * Some targets may set slight variations of PQ and PDT to signal
1239 	 * that no LUN is present, so don't add sdev in these cases.
1240 	 * Two specific examples are:
1241 	 * 1) NetApp targets: return PQ=1, PDT=0x1f
1242 	 * 2) USB UFI: returns PDT=0x1f, with the PQ bits being "reserved"
1243 	 *    in the UFI 1.0 spec (we cannot rely on reserved bits).
1244 	 *
1245 	 * References:
1246 	 * 1) SCSI SPC-3, pp. 145-146
1247 	 * PQ=1: "A peripheral device having the specified peripheral
1248 	 * device type is not connected to this logical unit. However, the
1249 	 * device server is capable of supporting the specified peripheral
1250 	 * device type on this logical unit."
1251 	 * PDT=0x1f: "Unknown or no device type"
1252 	 * 2) USB UFI 1.0, p. 20
1253 	 * PDT=00h Direct-access device (floppy)
1254 	 * PDT=1Fh none (no FDD connected to the requested logical unit)
1255 	 */
1256 	if (((result[0] >> 5) == 1 || starget->pdt_1f_for_no_lun) &&
1257 	    (result[0] & 0x1f) == 0x1f &&
1258 	    !scsi_is_wlun(lun)) {
1259 		SCSI_LOG_SCAN_BUS(3, sdev_printk(KERN_INFO, sdev,
1260 					"scsi scan: peripheral device type"
1261 					" of 31, no device added\n"));
1262 		res = SCSI_SCAN_TARGET_PRESENT;
1263 		goto out_free_result;
1264 	}
1265 
1266 	res = scsi_add_lun(sdev, result, &bflags, shost->async_scan);
1267 	if (res == SCSI_SCAN_LUN_PRESENT) {
1268 		if (bflags & BLIST_KEY) {
1269 			sdev->lockable = 0;
1270 			scsi_unlock_floptical(sdev, result);
1271 		}
1272 	}
1273 
1274  out_free_result:
1275 	kfree(result);
1276  out_free_sdev:
1277 	if (res == SCSI_SCAN_LUN_PRESENT) {
1278 		if (sdevp) {
1279 			if (scsi_device_get(sdev) == 0) {
1280 				*sdevp = sdev;
1281 			} else {
1282 				__scsi_remove_device(sdev);
1283 				res = SCSI_SCAN_NO_RESPONSE;
1284 			}
1285 		}
1286 	} else
1287 		__scsi_remove_device(sdev);
1288  out:
1289 	return res;
1290 }
1291 
1292 /**
1293  * scsi_sequential_lun_scan - sequentially scan a SCSI target
1294  * @starget:	pointer to target structure to scan
1295  * @bflags:	black/white list flag for LUN 0
1296  * @scsi_level: Which version of the standard does this device adhere to
1297  * @rescan:     passed to scsi_probe_add_lun()
1298  *
1299  * Description:
1300  *     Generally, scan from LUN 1 (LUN 0 is assumed to already have been
1301  *     scanned) to some maximum lun until a LUN is found with no device
1302  *     attached. Use the bflags to figure out any oddities.
1303  *
1304  *     Modifies sdevscan->lun.
1305  **/
scsi_sequential_lun_scan(struct scsi_target * starget,blist_flags_t bflags,int scsi_level,enum scsi_scan_mode rescan)1306 static void scsi_sequential_lun_scan(struct scsi_target *starget,
1307 				     blist_flags_t bflags, int scsi_level,
1308 				     enum scsi_scan_mode rescan)
1309 {
1310 	uint max_dev_lun;
1311 	u64 sparse_lun, lun;
1312 	struct Scsi_Host *shost = dev_to_shost(starget->dev.parent);
1313 
1314 	SCSI_LOG_SCAN_BUS(3, starget_printk(KERN_INFO, starget,
1315 		"scsi scan: Sequential scan\n"));
1316 
1317 	max_dev_lun = min(max_scsi_luns, shost->max_lun);
1318 	/*
1319 	 * If this device is known to support sparse multiple units,
1320 	 * override the other settings, and scan all of them. Normally,
1321 	 * SCSI-3 devices should be scanned via the REPORT LUNS.
1322 	 */
1323 	if (bflags & BLIST_SPARSELUN) {
1324 		max_dev_lun = shost->max_lun;
1325 		sparse_lun = 1;
1326 	} else
1327 		sparse_lun = 0;
1328 
1329 	/*
1330 	 * If less than SCSI_1_CCS, and no special lun scanning, stop
1331 	 * scanning; this matches 2.4 behaviour, but could just be a bug
1332 	 * (to continue scanning a SCSI_1_CCS device).
1333 	 *
1334 	 * This test is broken.  We might not have any device on lun0 for
1335 	 * a sparselun device, and if that's the case then how would we
1336 	 * know the real scsi_level, eh?  It might make sense to just not
1337 	 * scan any SCSI_1 device for non-0 luns, but that check would best
1338 	 * go into scsi_alloc_sdev() and just have it return null when asked
1339 	 * to alloc an sdev for lun > 0 on an already found SCSI_1 device.
1340 	 *
1341 	if ((sdevscan->scsi_level < SCSI_1_CCS) &&
1342 	    ((bflags & (BLIST_FORCELUN | BLIST_SPARSELUN | BLIST_MAX5LUN))
1343 	     == 0))
1344 		return;
1345 	 */
1346 	/*
1347 	 * If this device is known to support multiple units, override
1348 	 * the other settings, and scan all of them.
1349 	 */
1350 	if (bflags & BLIST_FORCELUN)
1351 		max_dev_lun = shost->max_lun;
1352 	/*
1353 	 * REGAL CDC-4X: avoid hang after LUN 4
1354 	 */
1355 	if (bflags & BLIST_MAX5LUN)
1356 		max_dev_lun = min(5U, max_dev_lun);
1357 	/*
1358 	 * Do not scan SCSI-2 or lower device past LUN 7, unless
1359 	 * BLIST_LARGELUN.
1360 	 */
1361 	if (scsi_level < SCSI_3 && !(bflags & BLIST_LARGELUN))
1362 		max_dev_lun = min(8U, max_dev_lun);
1363 	else
1364 		max_dev_lun = min(256U, max_dev_lun);
1365 
1366 	/*
1367 	 * We have already scanned LUN 0, so start at LUN 1. Keep scanning
1368 	 * until we reach the max, or no LUN is found and we are not
1369 	 * sparse_lun.
1370 	 */
1371 	for (lun = 1; lun < max_dev_lun; ++lun)
1372 		if ((scsi_probe_and_add_lun(starget, lun, NULL, NULL, rescan,
1373 					    NULL) != SCSI_SCAN_LUN_PRESENT) &&
1374 		    !sparse_lun)
1375 			return;
1376 }
1377 
1378 /**
1379  * scsi_report_lun_scan - Scan using SCSI REPORT LUN results
1380  * @starget: which target
1381  * @bflags: Zero or a mix of BLIST_NOLUN, BLIST_REPORTLUN2, or BLIST_NOREPORTLUN
1382  * @rescan: nonzero if we can skip code only needed on first scan
1383  *
1384  * Description:
1385  *   Fast scanning for modern (SCSI-3) devices by sending a REPORT LUN command.
1386  *   Scan the resulting list of LUNs by calling scsi_probe_and_add_lun.
1387  *
1388  *   If BLINK_REPORTLUN2 is set, scan a target that supports more than 8
1389  *   LUNs even if it's older than SCSI-3.
1390  *   If BLIST_NOREPORTLUN is set, return 1 always.
1391  *   If BLIST_NOLUN is set, return 0 always.
1392  *   If starget->no_report_luns is set, return 1 always.
1393  *
1394  * Return:
1395  *     0: scan completed (or no memory, so further scanning is futile)
1396  *     1: could not scan with REPORT LUN
1397  **/
scsi_report_lun_scan(struct scsi_target * starget,blist_flags_t bflags,enum scsi_scan_mode rescan)1398 static int scsi_report_lun_scan(struct scsi_target *starget, blist_flags_t bflags,
1399 				enum scsi_scan_mode rescan)
1400 {
1401 	unsigned char scsi_cmd[MAX_COMMAND_SIZE];
1402 	unsigned int length;
1403 	u64 lun;
1404 	unsigned int num_luns;
1405 	unsigned int retries;
1406 	int result;
1407 	struct scsi_lun *lunp, *lun_data;
1408 	struct scsi_sense_hdr sshdr;
1409 	struct scsi_device *sdev;
1410 	struct Scsi_Host *shost = dev_to_shost(&starget->dev);
1411 	const struct scsi_exec_args exec_args = {
1412 		.sshdr = &sshdr,
1413 	};
1414 	int ret = 0;
1415 
1416 	/*
1417 	 * Only support SCSI-3 and up devices if BLIST_NOREPORTLUN is not set.
1418 	 * Also allow SCSI-2 if BLIST_REPORTLUN2 is set and host adapter does
1419 	 * support more than 8 LUNs.
1420 	 * Don't attempt if the target doesn't support REPORT LUNS.
1421 	 */
1422 	if (bflags & BLIST_NOREPORTLUN)
1423 		return 1;
1424 	if (starget->scsi_level < SCSI_2 &&
1425 	    starget->scsi_level != SCSI_UNKNOWN)
1426 		return 1;
1427 	if (starget->scsi_level < SCSI_3 &&
1428 	    (!(bflags & BLIST_REPORTLUN2) || shost->max_lun <= 8))
1429 		return 1;
1430 	if (bflags & BLIST_NOLUN)
1431 		return 0;
1432 	if (starget->no_report_luns)
1433 		return 1;
1434 
1435 	if (!(sdev = scsi_device_lookup_by_target(starget, 0))) {
1436 		sdev = scsi_alloc_sdev(starget, 0, NULL);
1437 		if (!sdev)
1438 			return 0;
1439 		if (scsi_device_get(sdev)) {
1440 			__scsi_remove_device(sdev);
1441 			return 0;
1442 		}
1443 	}
1444 
1445 	/*
1446 	 * Allocate enough to hold the header (the same size as one scsi_lun)
1447 	 * plus the number of luns we are requesting.  511 was the default
1448 	 * value of the now removed max_report_luns parameter.
1449 	 */
1450 	length = (511 + 1) * sizeof(struct scsi_lun);
1451 retry:
1452 	lun_data = kmalloc(length, GFP_KERNEL);
1453 	if (!lun_data) {
1454 		printk(ALLOC_FAILURE_MSG, __func__);
1455 		goto out;
1456 	}
1457 
1458 	scsi_cmd[0] = REPORT_LUNS;
1459 
1460 	/*
1461 	 * bytes 1 - 5: reserved, set to zero.
1462 	 */
1463 	memset(&scsi_cmd[1], 0, 5);
1464 
1465 	/*
1466 	 * bytes 6 - 9: length of the command.
1467 	 */
1468 	put_unaligned_be32(length, &scsi_cmd[6]);
1469 
1470 	scsi_cmd[10] = 0;	/* reserved */
1471 	scsi_cmd[11] = 0;	/* control */
1472 
1473 	/*
1474 	 * We can get a UNIT ATTENTION, for example a power on/reset, so
1475 	 * retry a few times (like sd.c does for TEST UNIT READY).
1476 	 * Experience shows some combinations of adapter/devices get at
1477 	 * least two power on/resets.
1478 	 *
1479 	 * Illegal requests (for devices that do not support REPORT LUNS)
1480 	 * should come through as a check condition, and will not generate
1481 	 * a retry.
1482 	 */
1483 	for (retries = 0; retries < 3; retries++) {
1484 		SCSI_LOG_SCAN_BUS(3, sdev_printk (KERN_INFO, sdev,
1485 				"scsi scan: Sending REPORT LUNS to (try %d)\n",
1486 				retries));
1487 
1488 		result = scsi_execute_cmd(sdev, scsi_cmd, REQ_OP_DRV_IN,
1489 					  lun_data, length,
1490 					  SCSI_REPORT_LUNS_TIMEOUT, 3,
1491 					  &exec_args);
1492 
1493 		SCSI_LOG_SCAN_BUS(3, sdev_printk (KERN_INFO, sdev,
1494 				"scsi scan: REPORT LUNS"
1495 				" %s (try %d) result 0x%x\n",
1496 				result ?  "failed" : "successful",
1497 				retries, result));
1498 		if (result == 0)
1499 			break;
1500 		else if (scsi_sense_valid(&sshdr)) {
1501 			if (sshdr.sense_key != UNIT_ATTENTION)
1502 				break;
1503 		}
1504 	}
1505 
1506 	if (result) {
1507 		/*
1508 		 * The device probably does not support a REPORT LUN command
1509 		 */
1510 		ret = 1;
1511 		goto out_err;
1512 	}
1513 
1514 	/*
1515 	 * Get the length from the first four bytes of lun_data.
1516 	 */
1517 	if (get_unaligned_be32(lun_data->scsi_lun) +
1518 	    sizeof(struct scsi_lun) > length) {
1519 		length = get_unaligned_be32(lun_data->scsi_lun) +
1520 			 sizeof(struct scsi_lun);
1521 		kfree(lun_data);
1522 		goto retry;
1523 	}
1524 	length = get_unaligned_be32(lun_data->scsi_lun);
1525 
1526 	num_luns = (length / sizeof(struct scsi_lun));
1527 
1528 	SCSI_LOG_SCAN_BUS(3, sdev_printk (KERN_INFO, sdev,
1529 		"scsi scan: REPORT LUN scan\n"));
1530 
1531 	/*
1532 	 * Scan the luns in lun_data. The entry at offset 0 is really
1533 	 * the header, so start at 1 and go up to and including num_luns.
1534 	 */
1535 	for (lunp = &lun_data[1]; lunp <= &lun_data[num_luns]; lunp++) {
1536 		lun = scsilun_to_int(lunp);
1537 
1538 		if (lun > sdev->host->max_lun) {
1539 			sdev_printk(KERN_WARNING, sdev,
1540 				    "lun%llu has a LUN larger than"
1541 				    " allowed by the host adapter\n", lun);
1542 		} else {
1543 			int res;
1544 
1545 			res = scsi_probe_and_add_lun(starget,
1546 				lun, NULL, NULL, rescan, NULL);
1547 			if (res == SCSI_SCAN_NO_RESPONSE) {
1548 				/*
1549 				 * Got some results, but now none, abort.
1550 				 */
1551 				sdev_printk(KERN_ERR, sdev,
1552 					"Unexpected response"
1553 					" from lun %llu while scanning, scan"
1554 					" aborted\n", (unsigned long long)lun);
1555 				break;
1556 			}
1557 		}
1558 	}
1559 
1560  out_err:
1561 	kfree(lun_data);
1562  out:
1563 	if (scsi_device_created(sdev))
1564 		/*
1565 		 * the sdev we used didn't appear in the report luns scan
1566 		 */
1567 		__scsi_remove_device(sdev);
1568 	scsi_device_put(sdev);
1569 	return ret;
1570 }
1571 
__scsi_add_device(struct Scsi_Host * shost,uint channel,uint id,u64 lun,void * hostdata)1572 struct scsi_device *__scsi_add_device(struct Scsi_Host *shost, uint channel,
1573 				      uint id, u64 lun, void *hostdata)
1574 {
1575 	struct scsi_device *sdev = ERR_PTR(-ENODEV);
1576 	struct device *parent = &shost->shost_gendev;
1577 	struct scsi_target *starget;
1578 
1579 	if (strncmp(scsi_scan_type, "none", 4) == 0)
1580 		return ERR_PTR(-ENODEV);
1581 
1582 	starget = scsi_alloc_target(parent, channel, id);
1583 	if (!starget)
1584 		return ERR_PTR(-ENOMEM);
1585 	scsi_autopm_get_target(starget);
1586 
1587 	mutex_lock(&shost->scan_mutex);
1588 	if (!shost->async_scan)
1589 		scsi_complete_async_scans();
1590 
1591 	if (scsi_host_scan_allowed(shost) && scsi_autopm_get_host(shost) == 0) {
1592 		scsi_probe_and_add_lun(starget, lun, NULL, &sdev,
1593 				       SCSI_SCAN_RESCAN, hostdata);
1594 		scsi_autopm_put_host(shost);
1595 	}
1596 	mutex_unlock(&shost->scan_mutex);
1597 	scsi_autopm_put_target(starget);
1598 	/*
1599 	 * paired with scsi_alloc_target().  Target will be destroyed unless
1600 	 * scsi_probe_and_add_lun made an underlying device visible
1601 	 */
1602 	scsi_target_reap(starget);
1603 	put_device(&starget->dev);
1604 
1605 	return sdev;
1606 }
1607 EXPORT_SYMBOL(__scsi_add_device);
1608 
scsi_add_device(struct Scsi_Host * host,uint channel,uint target,u64 lun)1609 int scsi_add_device(struct Scsi_Host *host, uint channel,
1610 		    uint target, u64 lun)
1611 {
1612 	struct scsi_device *sdev =
1613 		__scsi_add_device(host, channel, target, lun, NULL);
1614 	if (IS_ERR(sdev))
1615 		return PTR_ERR(sdev);
1616 
1617 	scsi_device_put(sdev);
1618 	return 0;
1619 }
1620 EXPORT_SYMBOL(scsi_add_device);
1621 
scsi_rescan_device(struct scsi_device * sdev)1622 int scsi_rescan_device(struct scsi_device *sdev)
1623 {
1624 	struct device *dev = &sdev->sdev_gendev;
1625 	int ret = 0;
1626 
1627 	device_lock(dev);
1628 
1629 	/*
1630 	 * Bail out if the device or its queue are not running. Otherwise,
1631 	 * the rescan may block waiting for commands to be executed, with us
1632 	 * holding the device lock. This can result in a potential deadlock
1633 	 * in the power management core code when system resume is on-going.
1634 	 */
1635 	if (sdev->sdev_state != SDEV_RUNNING ||
1636 	    blk_queue_pm_only(sdev->request_queue)) {
1637 		ret = -EWOULDBLOCK;
1638 		goto unlock;
1639 	}
1640 
1641 	scsi_attach_vpd(sdev);
1642 	scsi_cdl_check(sdev);
1643 
1644 	if (sdev->handler && sdev->handler->rescan)
1645 		sdev->handler->rescan(sdev);
1646 
1647 	if (dev->driver && try_module_get(dev->driver->owner)) {
1648 		struct scsi_driver *drv = to_scsi_driver(dev->driver);
1649 
1650 		if (drv->rescan)
1651 			drv->rescan(dev);
1652 		module_put(dev->driver->owner);
1653 	}
1654 
1655 unlock:
1656 	device_unlock(dev);
1657 
1658 	return ret;
1659 }
1660 EXPORT_SYMBOL(scsi_rescan_device);
1661 
__scsi_scan_target(struct device * parent,unsigned int channel,unsigned int id,u64 lun,enum scsi_scan_mode rescan)1662 static void __scsi_scan_target(struct device *parent, unsigned int channel,
1663 		unsigned int id, u64 lun, enum scsi_scan_mode rescan)
1664 {
1665 	struct Scsi_Host *shost = dev_to_shost(parent);
1666 	blist_flags_t bflags = 0;
1667 	int res;
1668 	struct scsi_target *starget;
1669 
1670 	if (shost->this_id == id)
1671 		/*
1672 		 * Don't scan the host adapter
1673 		 */
1674 		return;
1675 
1676 	starget = scsi_alloc_target(parent, channel, id);
1677 	if (!starget)
1678 		return;
1679 	scsi_autopm_get_target(starget);
1680 
1681 	if (lun != SCAN_WILD_CARD) {
1682 		/*
1683 		 * Scan for a specific host/chan/id/lun.
1684 		 */
1685 		scsi_probe_and_add_lun(starget, lun, NULL, NULL, rescan, NULL);
1686 		goto out_reap;
1687 	}
1688 
1689 	/*
1690 	 * Scan LUN 0, if there is some response, scan further. Ideally, we
1691 	 * would not configure LUN 0 until all LUNs are scanned.
1692 	 */
1693 	res = scsi_probe_and_add_lun(starget, 0, &bflags, NULL, rescan, NULL);
1694 	if (res == SCSI_SCAN_LUN_PRESENT || res == SCSI_SCAN_TARGET_PRESENT) {
1695 		if (scsi_report_lun_scan(starget, bflags, rescan) != 0)
1696 			/*
1697 			 * The REPORT LUN did not scan the target,
1698 			 * do a sequential scan.
1699 			 */
1700 			scsi_sequential_lun_scan(starget, bflags,
1701 						 starget->scsi_level, rescan);
1702 	}
1703 
1704  out_reap:
1705 	scsi_autopm_put_target(starget);
1706 	/*
1707 	 * paired with scsi_alloc_target(): determine if the target has
1708 	 * any children at all and if not, nuke it
1709 	 */
1710 	scsi_target_reap(starget);
1711 
1712 	put_device(&starget->dev);
1713 }
1714 
1715 /**
1716  * scsi_scan_target - scan a target id, possibly including all LUNs on the target.
1717  * @parent:	host to scan
1718  * @channel:	channel to scan
1719  * @id:		target id to scan
1720  * @lun:	Specific LUN to scan or SCAN_WILD_CARD
1721  * @rescan:	passed to LUN scanning routines; SCSI_SCAN_INITIAL for
1722  *              no rescan, SCSI_SCAN_RESCAN to rescan existing LUNs,
1723  *              and SCSI_SCAN_MANUAL to force scanning even if
1724  *              'scan=manual' is set.
1725  *
1726  * Description:
1727  *     Scan the target id on @parent, @channel, and @id. Scan at least LUN 0,
1728  *     and possibly all LUNs on the target id.
1729  *
1730  *     First try a REPORT LUN scan, if that does not scan the target, do a
1731  *     sequential scan of LUNs on the target id.
1732  **/
scsi_scan_target(struct device * parent,unsigned int channel,unsigned int id,u64 lun,enum scsi_scan_mode rescan)1733 void scsi_scan_target(struct device *parent, unsigned int channel,
1734 		      unsigned int id, u64 lun, enum scsi_scan_mode rescan)
1735 {
1736 	struct Scsi_Host *shost = dev_to_shost(parent);
1737 
1738 	if (strncmp(scsi_scan_type, "none", 4) == 0)
1739 		return;
1740 
1741 	if (rescan != SCSI_SCAN_MANUAL &&
1742 	    strncmp(scsi_scan_type, "manual", 6) == 0)
1743 		return;
1744 
1745 	mutex_lock(&shost->scan_mutex);
1746 	if (!shost->async_scan)
1747 		scsi_complete_async_scans();
1748 
1749 	if (scsi_host_scan_allowed(shost) && scsi_autopm_get_host(shost) == 0) {
1750 		__scsi_scan_target(parent, channel, id, lun, rescan);
1751 		scsi_autopm_put_host(shost);
1752 	}
1753 	mutex_unlock(&shost->scan_mutex);
1754 }
1755 EXPORT_SYMBOL(scsi_scan_target);
1756 
scsi_scan_channel(struct Scsi_Host * shost,unsigned int channel,unsigned int id,u64 lun,enum scsi_scan_mode rescan)1757 static void scsi_scan_channel(struct Scsi_Host *shost, unsigned int channel,
1758 			      unsigned int id, u64 lun,
1759 			      enum scsi_scan_mode rescan)
1760 {
1761 	uint order_id;
1762 
1763 	if (id == SCAN_WILD_CARD)
1764 		for (id = 0; id < shost->max_id; ++id) {
1765 			/*
1766 			 * XXX adapter drivers when possible (FCP, iSCSI)
1767 			 * could modify max_id to match the current max,
1768 			 * not the absolute max.
1769 			 *
1770 			 * XXX add a shost id iterator, so for example,
1771 			 * the FC ID can be the same as a target id
1772 			 * without a huge overhead of sparse id's.
1773 			 */
1774 			if (shost->reverse_ordering)
1775 				/*
1776 				 * Scan from high to low id.
1777 				 */
1778 				order_id = shost->max_id - id - 1;
1779 			else
1780 				order_id = id;
1781 			__scsi_scan_target(&shost->shost_gendev, channel,
1782 					order_id, lun, rescan);
1783 		}
1784 	else
1785 		__scsi_scan_target(&shost->shost_gendev, channel,
1786 				id, lun, rescan);
1787 }
1788 
scsi_scan_host_selected(struct Scsi_Host * shost,unsigned int channel,unsigned int id,u64 lun,enum scsi_scan_mode rescan)1789 int scsi_scan_host_selected(struct Scsi_Host *shost, unsigned int channel,
1790 			    unsigned int id, u64 lun,
1791 			    enum scsi_scan_mode rescan)
1792 {
1793 	SCSI_LOG_SCAN_BUS(3, shost_printk (KERN_INFO, shost,
1794 		"%s: <%u:%u:%llu>\n",
1795 		__func__, channel, id, lun));
1796 
1797 	if (((channel != SCAN_WILD_CARD) && (channel > shost->max_channel)) ||
1798 	    ((id != SCAN_WILD_CARD) && (id >= shost->max_id)) ||
1799 	    ((lun != SCAN_WILD_CARD) && (lun >= shost->max_lun)))
1800 		return -EINVAL;
1801 
1802 	mutex_lock(&shost->scan_mutex);
1803 	if (!shost->async_scan)
1804 		scsi_complete_async_scans();
1805 
1806 	if (scsi_host_scan_allowed(shost) && scsi_autopm_get_host(shost) == 0) {
1807 		if (channel == SCAN_WILD_CARD)
1808 			for (channel = 0; channel <= shost->max_channel;
1809 			     channel++)
1810 				scsi_scan_channel(shost, channel, id, lun,
1811 						  rescan);
1812 		else
1813 			scsi_scan_channel(shost, channel, id, lun, rescan);
1814 		scsi_autopm_put_host(shost);
1815 	}
1816 	mutex_unlock(&shost->scan_mutex);
1817 
1818 	return 0;
1819 }
1820 
scsi_sysfs_add_devices(struct Scsi_Host * shost)1821 static void scsi_sysfs_add_devices(struct Scsi_Host *shost)
1822 {
1823 	struct scsi_device *sdev;
1824 	shost_for_each_device(sdev, shost) {
1825 		/* target removed before the device could be added */
1826 		if (sdev->sdev_state == SDEV_DEL)
1827 			continue;
1828 		/* If device is already visible, skip adding it to sysfs */
1829 		if (sdev->is_visible)
1830 			continue;
1831 		if (!scsi_host_scan_allowed(shost) ||
1832 		    scsi_sysfs_add_sdev(sdev) != 0)
1833 			__scsi_remove_device(sdev);
1834 	}
1835 }
1836 
1837 /**
1838  * scsi_prep_async_scan - prepare for an async scan
1839  * @shost: the host which will be scanned
1840  * Returns: a cookie to be passed to scsi_finish_async_scan()
1841  *
1842  * Tells the midlayer this host is going to do an asynchronous scan.
1843  * It reserves the host's position in the scanning list and ensures
1844  * that other asynchronous scans started after this one won't affect the
1845  * ordering of the discovered devices.
1846  */
scsi_prep_async_scan(struct Scsi_Host * shost)1847 static struct async_scan_data *scsi_prep_async_scan(struct Scsi_Host *shost)
1848 {
1849 	struct async_scan_data *data = NULL;
1850 	unsigned long flags;
1851 
1852 	if (strncmp(scsi_scan_type, "sync", 4) == 0)
1853 		return NULL;
1854 
1855 	mutex_lock(&shost->scan_mutex);
1856 	if (shost->async_scan) {
1857 		shost_printk(KERN_DEBUG, shost, "%s called twice\n", __func__);
1858 		goto err;
1859 	}
1860 
1861 	data = kmalloc(sizeof(*data), GFP_KERNEL);
1862 	if (!data)
1863 		goto err;
1864 	data->shost = scsi_host_get(shost);
1865 	if (!data->shost)
1866 		goto err;
1867 	init_completion(&data->prev_finished);
1868 
1869 	spin_lock_irqsave(shost->host_lock, flags);
1870 	shost->async_scan = 1;
1871 	spin_unlock_irqrestore(shost->host_lock, flags);
1872 	mutex_unlock(&shost->scan_mutex);
1873 
1874 	spin_lock(&async_scan_lock);
1875 	if (list_empty(&scanning_hosts))
1876 		complete(&data->prev_finished);
1877 	list_add_tail(&data->list, &scanning_hosts);
1878 	spin_unlock(&async_scan_lock);
1879 
1880 	return data;
1881 
1882  err:
1883 	mutex_unlock(&shost->scan_mutex);
1884 	kfree(data);
1885 	return NULL;
1886 }
1887 
1888 /**
1889  * scsi_finish_async_scan - asynchronous scan has finished
1890  * @data: cookie returned from earlier call to scsi_prep_async_scan()
1891  *
1892  * All the devices currently attached to this host have been found.
1893  * This function announces all the devices it has found to the rest
1894  * of the system.
1895  */
scsi_finish_async_scan(struct async_scan_data * data)1896 static void scsi_finish_async_scan(struct async_scan_data *data)
1897 {
1898 	struct Scsi_Host *shost;
1899 	unsigned long flags;
1900 
1901 	if (!data)
1902 		return;
1903 
1904 	shost = data->shost;
1905 
1906 	mutex_lock(&shost->scan_mutex);
1907 
1908 	if (!shost->async_scan) {
1909 		shost_printk(KERN_INFO, shost, "%s called twice\n", __func__);
1910 		dump_stack();
1911 		mutex_unlock(&shost->scan_mutex);
1912 		return;
1913 	}
1914 
1915 	wait_for_completion(&data->prev_finished);
1916 
1917 	scsi_sysfs_add_devices(shost);
1918 
1919 	spin_lock_irqsave(shost->host_lock, flags);
1920 	shost->async_scan = 0;
1921 	spin_unlock_irqrestore(shost->host_lock, flags);
1922 
1923 	mutex_unlock(&shost->scan_mutex);
1924 
1925 	spin_lock(&async_scan_lock);
1926 	list_del(&data->list);
1927 	if (!list_empty(&scanning_hosts)) {
1928 		struct async_scan_data *next = list_entry(scanning_hosts.next,
1929 				struct async_scan_data, list);
1930 		complete(&next->prev_finished);
1931 	}
1932 	spin_unlock(&async_scan_lock);
1933 
1934 	scsi_autopm_put_host(shost);
1935 	scsi_host_put(shost);
1936 	kfree(data);
1937 }
1938 
do_scsi_scan_host(struct Scsi_Host * shost)1939 static void do_scsi_scan_host(struct Scsi_Host *shost)
1940 {
1941 	if (shost->hostt->scan_finished) {
1942 		unsigned long start = jiffies;
1943 		if (shost->hostt->scan_start)
1944 			shost->hostt->scan_start(shost);
1945 
1946 		while (!shost->hostt->scan_finished(shost, jiffies - start))
1947 			msleep(10);
1948 	} else {
1949 		scsi_scan_host_selected(shost, SCAN_WILD_CARD, SCAN_WILD_CARD,
1950 				SCAN_WILD_CARD, SCSI_SCAN_INITIAL);
1951 	}
1952 }
1953 
do_scan_async(void * _data,async_cookie_t c)1954 static void do_scan_async(void *_data, async_cookie_t c)
1955 {
1956 	struct async_scan_data *data = _data;
1957 	struct Scsi_Host *shost = data->shost;
1958 
1959 	do_scsi_scan_host(shost);
1960 	scsi_finish_async_scan(data);
1961 }
1962 
1963 /**
1964  * scsi_scan_host - scan the given adapter
1965  * @shost:	adapter to scan
1966  **/
scsi_scan_host(struct Scsi_Host * shost)1967 void scsi_scan_host(struct Scsi_Host *shost)
1968 {
1969 	struct async_scan_data *data;
1970 
1971 	if (strncmp(scsi_scan_type, "none", 4) == 0 ||
1972 	    strncmp(scsi_scan_type, "manual", 6) == 0)
1973 		return;
1974 	if (scsi_autopm_get_host(shost) < 0)
1975 		return;
1976 
1977 	data = scsi_prep_async_scan(shost);
1978 	if (!data) {
1979 		do_scsi_scan_host(shost);
1980 		scsi_autopm_put_host(shost);
1981 		return;
1982 	}
1983 
1984 	/* register with the async subsystem so wait_for_device_probe()
1985 	 * will flush this work
1986 	 */
1987 	async_schedule(do_scan_async, data);
1988 
1989 	/* scsi_autopm_put_host(shost) is called in scsi_finish_async_scan() */
1990 }
1991 EXPORT_SYMBOL(scsi_scan_host);
1992 
scsi_forget_host(struct Scsi_Host * shost)1993 void scsi_forget_host(struct Scsi_Host *shost)
1994 {
1995 	struct scsi_device *sdev;
1996 	unsigned long flags;
1997 
1998  restart:
1999 	spin_lock_irqsave(shost->host_lock, flags);
2000 	list_for_each_entry(sdev, &shost->__devices, siblings) {
2001 		if (sdev->sdev_state == SDEV_DEL)
2002 			continue;
2003 		spin_unlock_irqrestore(shost->host_lock, flags);
2004 		__scsi_remove_device(sdev);
2005 		goto restart;
2006 	}
2007 	spin_unlock_irqrestore(shost->host_lock, flags);
2008 }
2009 
2010