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/module.h>
  29#include <linux/moduleparam.h>
  30#include <linux/init.h>
  31#include <linux/blkdev.h>
  32#include <linux/delay.h>
  33#include <linux/kthread.h>
  34#include <linux/spinlock.h>
  35#include <linux/async.h>
  36#include <linux/slab.h>
  37#include <asm/unaligned.h>
  38
  39#include <scsi/scsi.h>
  40#include <scsi/scsi_cmnd.h>
  41#include <scsi/scsi_device.h>
  42#include <scsi/scsi_driver.h>
  43#include <scsi/scsi_devinfo.h>
  44#include <scsi/scsi_host.h>
  45#include <scsi/scsi_transport.h>
  46#include <scsi/scsi_dh.h>
  47#include <scsi/scsi_eh.h>
  48
  49#include "scsi_priv.h"
  50#include "scsi_logging.h"
  51
  52#define ALLOC_FAILURE_MSG	KERN_ERR "%s: Allocation failure during" \
  53	" SCSI scanning, some SCSI devices might not be configured\n"
  54
  55/*
  56 * Default timeout
  57 */
  58#define SCSI_TIMEOUT (2*HZ)
  59#define SCSI_REPORT_LUNS_TIMEOUT (30*HZ)
  60
  61/*
  62 * Prefix values for the SCSI id's (stored in sysfs name field)
  63 */
  64#define SCSI_UID_SER_NUM 'S'
  65#define SCSI_UID_UNKNOWN 'Z'
  66
  67/*
  68 * Return values of some of the scanning functions.
  69 *
  70 * SCSI_SCAN_NO_RESPONSE: no valid response received from the target, this
  71 * includes allocation or general failures preventing IO from being sent.
  72 *
  73 * SCSI_SCAN_TARGET_PRESENT: target responded, but no device is available
  74 * on the given LUN.
  75 *
  76 * SCSI_SCAN_LUN_PRESENT: target responded, and a device is available on a
  77 * given LUN.
  78 */
  79#define SCSI_SCAN_NO_RESPONSE		0
  80#define SCSI_SCAN_TARGET_PRESENT	1
  81#define SCSI_SCAN_LUN_PRESENT		2
  82
  83static const char *scsi_null_device_strs = "nullnullnullnull";
  84
  85#define MAX_SCSI_LUNS	512
  86
  87static u64 max_scsi_luns = MAX_SCSI_LUNS;
  88
  89module_param_named(max_luns, max_scsi_luns, ullong, S_IRUGO|S_IWUSR);
  90MODULE_PARM_DESC(max_luns,
  91		 "last scsi LUN (should be between 1 and 2^64-1)");
  92
  93#ifdef CONFIG_SCSI_SCAN_ASYNC
  94#define SCSI_SCAN_TYPE_DEFAULT "async"
  95#else
  96#define SCSI_SCAN_TYPE_DEFAULT "sync"
  97#endif
  98
  99char scsi_scan_type[7] = SCSI_SCAN_TYPE_DEFAULT;
 100
 101module_param_string(scan, scsi_scan_type, sizeof(scsi_scan_type),
 102		    S_IRUGO|S_IWUSR);
 103MODULE_PARM_DESC(scan, "sync, async, manual, or none. "
 104		 "Setting to 'manual' disables automatic scanning, but allows "
 105		 "for manual device scan via the 'scan' sysfs attribute.");
 106
 107static unsigned int scsi_inq_timeout = SCSI_TIMEOUT/HZ + 18;
 108
 109module_param_named(inq_timeout, scsi_inq_timeout, uint, S_IRUGO|S_IWUSR);
 110MODULE_PARM_DESC(inq_timeout, 
 111		 "Timeout (in seconds) waiting for devices to answer INQUIRY."
 112		 " Default is 20. Some devices may need more; most need less.");
 113
 114/* This lock protects only this list */
 115static DEFINE_SPINLOCK(async_scan_lock);
 116static LIST_HEAD(scanning_hosts);
 117
 118struct async_scan_data {
 119	struct list_head list;
 120	struct Scsi_Host *shost;
 121	struct completion prev_finished;
 122};
 123
 124/**
 125 * scsi_complete_async_scans - Wait for asynchronous scans to complete
 126 *
 127 * When this function returns, any host which started scanning before
 128 * this function was called will have finished its scan.  Hosts which
 129 * started scanning after this function was called may or may not have
 130 * finished.
 131 */
 132int scsi_complete_async_scans(void)
 133{
 134	struct async_scan_data *data;
 135
 136	do {
 137		if (list_empty(&scanning_hosts))
 138			return 0;
 139		/* If we can't get memory immediately, that's OK.  Just
 140		 * sleep a little.  Even if we never get memory, the async
 141		 * scans will finish eventually.
 142		 */
 143		data = kmalloc(sizeof(*data), GFP_KERNEL);
 144		if (!data)
 145			msleep(1);
 146	} while (!data);
 147
 148	data->shost = NULL;
 149	init_completion(&data->prev_finished);
 150
 151	spin_lock(&async_scan_lock);
 152	/* Check that there's still somebody else on the list */
 153	if (list_empty(&scanning_hosts))
 154		goto done;
 155	list_add_tail(&data->list, &scanning_hosts);
 156	spin_unlock(&async_scan_lock);
 157
 158	printk(KERN_INFO "scsi: waiting for bus probes to complete ...\n");
 159	wait_for_completion(&data->prev_finished);
 160
 161	spin_lock(&async_scan_lock);
 162	list_del(&data->list);
 163	if (!list_empty(&scanning_hosts)) {
 164		struct async_scan_data *next = list_entry(scanning_hosts.next,
 165				struct async_scan_data, list);
 166		complete(&next->prev_finished);
 167	}
 168 done:
 169	spin_unlock(&async_scan_lock);
 170
 171	kfree(data);
 172	return 0;
 173}
 174
 175/**
 176 * scsi_unlock_floptical - unlock device via a special MODE SENSE command
 177 * @sdev:	scsi device to send command to
 178 * @result:	area to store the result of the MODE SENSE
 179 *
 180 * Description:
 181 *     Send a vendor specific MODE SENSE (not a MODE SELECT) command.
 182 *     Called for BLIST_KEY devices.
 183 **/
 184static void scsi_unlock_floptical(struct scsi_device *sdev,
 185				  unsigned char *result)
 186{
 187	unsigned char scsi_cmd[MAX_COMMAND_SIZE];
 188
 189	sdev_printk(KERN_NOTICE, sdev, "unlocking floptical drive\n");
 190	scsi_cmd[0] = MODE_SENSE;
 191	scsi_cmd[1] = 0;
 192	scsi_cmd[2] = 0x2e;
 193	scsi_cmd[3] = 0;
 194	scsi_cmd[4] = 0x2a;     /* size */
 195	scsi_cmd[5] = 0;
 196	scsi_execute_req(sdev, scsi_cmd, DMA_FROM_DEVICE, result, 0x2a, NULL,
 197			 SCSI_TIMEOUT, 3, NULL);
 198}
 199
 200/**
 201 * scsi_alloc_sdev - allocate and setup a scsi_Device
 202 * @starget: which target to allocate a &scsi_device for
 203 * @lun: which lun
 204 * @hostdata: usually NULL and set by ->slave_alloc instead
 205 *
 206 * Description:
 207 *     Allocate, initialize for io, and return a pointer to a scsi_Device.
 208 *     Stores the @shost, @channel, @id, and @lun in the scsi_Device, and
 209 *     adds scsi_Device to the appropriate list.
 210 *
 211 * Return value:
 212 *     scsi_Device pointer, or NULL on failure.
 213 **/
 214static struct scsi_device *scsi_alloc_sdev(struct scsi_target *starget,
 215					   u64 lun, void *hostdata)
 216{
 217	struct scsi_device *sdev;
 218	int display_failure_msg = 1, ret;
 219	struct Scsi_Host *shost = dev_to_shost(starget->dev.parent);
 220
 221	sdev = kzalloc(sizeof(*sdev) + shost->transportt->device_size,
 222		       GFP_ATOMIC);
 223	if (!sdev)
 224		goto out;
 225
 226	sdev->vendor = scsi_null_device_strs;
 227	sdev->model = scsi_null_device_strs;
 228	sdev->rev = scsi_null_device_strs;
 229	sdev->host = shost;
 230	sdev->queue_ramp_up_period = SCSI_DEFAULT_RAMP_UP_PERIOD;
 231	sdev->id = starget->id;
 232	sdev->lun = lun;
 233	sdev->channel = starget->channel;
 
 234	sdev->sdev_state = SDEV_CREATED;
 235	INIT_LIST_HEAD(&sdev->siblings);
 236	INIT_LIST_HEAD(&sdev->same_target_siblings);
 237	INIT_LIST_HEAD(&sdev->cmd_list);
 238	INIT_LIST_HEAD(&sdev->starved_entry);
 239	INIT_LIST_HEAD(&sdev->event_list);
 240	spin_lock_init(&sdev->list_lock);
 241	mutex_init(&sdev->inquiry_mutex);
 242	INIT_WORK(&sdev->event_work, scsi_evt_thread);
 243	INIT_WORK(&sdev->requeue_work, scsi_requeue_run_queue);
 244
 245	sdev->sdev_gendev.parent = get_device(&starget->dev);
 246	sdev->sdev_target = starget;
 247
 248	/* usually NULL and set by ->slave_alloc instead */
 249	sdev->hostdata = hostdata;
 250
 251	/* if the device needs this changing, it may do so in the
 252	 * slave_configure function */
 253	sdev->max_device_blocked = SCSI_DEFAULT_DEVICE_BLOCKED;
 254
 255	/*
 256	 * Some low level driver could use device->type
 257	 */
 258	sdev->type = -1;
 259
 260	/*
 261	 * Assume that the device will have handshaking problems,
 262	 * and then fix this field later if it turns out it
 263	 * doesn't
 264	 */
 265	sdev->borken = 1;
 266
 267	if (shost_use_blk_mq(shost))
 268		sdev->request_queue = scsi_mq_alloc_queue(sdev);
 269	else
 270		sdev->request_queue = scsi_alloc_queue(sdev);
 271	if (!sdev->request_queue) {
 272		/* release fn is set up in scsi_sysfs_device_initialise, so
 273		 * have to free and put manually here */
 274		put_device(&starget->dev);
 275		kfree(sdev);
 276		goto out;
 277	}
 278	WARN_ON_ONCE(!blk_get_queue(sdev->request_queue));
 279	sdev->request_queue->queuedata = sdev;
 280
 281	if (!shost_use_blk_mq(sdev->host)) {
 282		blk_queue_init_tags(sdev->request_queue,
 283				    sdev->host->cmd_per_lun, shost->bqt,
 284				    shost->hostt->tag_alloc_policy);
 285	}
 286	scsi_change_queue_depth(sdev, sdev->host->cmd_per_lun ?
 287					sdev->host->cmd_per_lun : 1);
 288
 289	scsi_sysfs_device_initialize(sdev);
 290
 291	if (shost->hostt->slave_alloc) {
 292		ret = shost->hostt->slave_alloc(sdev);
 293		if (ret) {
 294			/*
 295			 * if LLDD reports slave not present, don't clutter
 296			 * console with alloc failure messages
 297			 */
 298			if (ret == -ENXIO)
 299				display_failure_msg = 0;
 300			goto out_device_destroy;
 301		}
 302	}
 303
 304	return sdev;
 305
 306out_device_destroy:
 307	__scsi_remove_device(sdev);
 308out:
 309	if (display_failure_msg)
 310		printk(ALLOC_FAILURE_MSG, __func__);
 311	return NULL;
 312}
 313
 314static void scsi_target_destroy(struct scsi_target *starget)
 315{
 316	struct device *dev = &starget->dev;
 317	struct Scsi_Host *shost = dev_to_shost(dev->parent);
 318	unsigned long flags;
 319
 320	BUG_ON(starget->state == STARGET_DEL);
 321	starget->state = STARGET_DEL;
 322	transport_destroy_device(dev);
 323	spin_lock_irqsave(shost->host_lock, flags);
 324	if (shost->hostt->target_destroy)
 325		shost->hostt->target_destroy(starget);
 326	list_del_init(&starget->siblings);
 327	spin_unlock_irqrestore(shost->host_lock, flags);
 328	put_device(dev);
 329}
 330
 331static void scsi_target_dev_release(struct device *dev)
 332{
 333	struct device *parent = dev->parent;
 334	struct scsi_target *starget = to_scsi_target(dev);
 335
 336	kfree(starget);
 337	put_device(parent);
 338}
 339
 340static struct device_type scsi_target_type = {
 341	.name =		"scsi_target",
 342	.release =	scsi_target_dev_release,
 343};
 344
 345int scsi_is_target_device(const struct device *dev)
 346{
 347	return dev->type == &scsi_target_type;
 348}
 349EXPORT_SYMBOL(scsi_is_target_device);
 350
 351static struct scsi_target *__scsi_find_target(struct device *parent,
 352					      int channel, uint id)
 353{
 354	struct scsi_target *starget, *found_starget = NULL;
 355	struct Scsi_Host *shost = dev_to_shost(parent);
 356	/*
 357	 * Search for an existing target for this sdev.
 358	 */
 359	list_for_each_entry(starget, &shost->__targets, siblings) {
 360		if (starget->id == id &&
 361		    starget->channel == channel) {
 362			found_starget = starget;
 363			break;
 364		}
 365	}
 366	if (found_starget)
 367		get_device(&found_starget->dev);
 368
 369	return found_starget;
 370}
 371
 372/**
 373 * scsi_target_reap_ref_release - remove target from visibility
 374 * @kref: the reap_ref in the target being released
 375 *
 376 * Called on last put of reap_ref, which is the indication that no device
 377 * under this target is visible anymore, so render the target invisible in
 378 * sysfs.  Note: we have to be in user context here because the target reaps
 379 * should be done in places where the scsi device visibility is being removed.
 380 */
 381static void scsi_target_reap_ref_release(struct kref *kref)
 382{
 383	struct scsi_target *starget
 384		= container_of(kref, struct scsi_target, reap_ref);
 385
 386	/*
 387	 * if we get here and the target is still in the CREATED state that
 388	 * means it was allocated but never made visible (because a scan
 389	 * turned up no LUNs), so don't call device_del() on it.
 390	 */
 391	if (starget->state != STARGET_CREATED) {
 
 392		transport_remove_device(&starget->dev);
 393		device_del(&starget->dev);
 394	}
 395	scsi_target_destroy(starget);
 396}
 397
 398static void scsi_target_reap_ref_put(struct scsi_target *starget)
 399{
 400	kref_put(&starget->reap_ref, scsi_target_reap_ref_release);
 401}
 402
 403/**
 404 * scsi_alloc_target - allocate a new or find an existing target
 405 * @parent:	parent of the target (need not be a scsi host)
 406 * @channel:	target channel number (zero if no channels)
 407 * @id:		target id number
 408 *
 409 * Return an existing target if one exists, provided it hasn't already
 410 * gone into STARGET_DEL state, otherwise allocate a new target.
 411 *
 412 * The target is returned with an incremented reference, so the caller
 413 * is responsible for both reaping and doing a last put
 414 */
 415static struct scsi_target *scsi_alloc_target(struct device *parent,
 416					     int channel, uint id)
 417{
 418	struct Scsi_Host *shost = dev_to_shost(parent);
 419	struct device *dev = NULL;
 420	unsigned long flags;
 421	const int size = sizeof(struct scsi_target)
 422		+ shost->transportt->target_size;
 423	struct scsi_target *starget;
 424	struct scsi_target *found_target;
 425	int error, ref_got;
 426
 427	starget = kzalloc(size, GFP_KERNEL);
 428	if (!starget) {
 429		printk(KERN_ERR "%s: allocation failure\n", __func__);
 430		return NULL;
 431	}
 432	dev = &starget->dev;
 433	device_initialize(dev);
 434	kref_init(&starget->reap_ref);
 435	dev->parent = get_device(parent);
 436	dev_set_name(dev, "target%d:%d:%d", shost->host_no, channel, id);
 437	dev->bus = &scsi_bus_type;
 438	dev->type = &scsi_target_type;
 439	starget->id = id;
 440	starget->channel = channel;
 441	starget->can_queue = 0;
 442	INIT_LIST_HEAD(&starget->siblings);
 443	INIT_LIST_HEAD(&starget->devices);
 444	starget->state = STARGET_CREATED;
 445	starget->scsi_level = SCSI_2;
 446	starget->max_target_blocked = SCSI_DEFAULT_TARGET_BLOCKED;
 447 retry:
 448	spin_lock_irqsave(shost->host_lock, flags);
 449
 450	found_target = __scsi_find_target(parent, channel, id);
 451	if (found_target)
 452		goto found;
 453
 454	list_add_tail(&starget->siblings, &shost->__targets);
 455	spin_unlock_irqrestore(shost->host_lock, flags);
 456	/* allocate and add */
 457	transport_setup_device(dev);
 458	if (shost->hostt->target_alloc) {
 459		error = shost->hostt->target_alloc(starget);
 460
 461		if(error) {
 462			dev_printk(KERN_ERR, dev, "target allocation failed, error %d\n", error);
 463			/* don't want scsi_target_reap to do the final
 464			 * put because it will be under the host lock */
 465			scsi_target_destroy(starget);
 466			return NULL;
 467		}
 468	}
 469	get_device(dev);
 470
 471	return starget;
 472
 473 found:
 474	/*
 475	 * release routine already fired if kref is zero, so if we can still
 476	 * take the reference, the target must be alive.  If we can't, it must
 477	 * be dying and we need to wait for a new target
 478	 */
 479	ref_got = kref_get_unless_zero(&found_target->reap_ref);
 480
 481	spin_unlock_irqrestore(shost->host_lock, flags);
 482	if (ref_got) {
 483		put_device(dev);
 484		return found_target;
 485	}
 486	/*
 487	 * Unfortunately, we found a dying target; need to wait until it's
 488	 * dead before we can get a new one.  There is an anomaly here.  We
 489	 * *should* call scsi_target_reap() to balance the kref_get() of the
 490	 * reap_ref above.  However, since the target being released, it's
 491	 * already invisible and the reap_ref is irrelevant.  If we call
 492	 * scsi_target_reap() we might spuriously do another device_del() on
 493	 * an already invisible target.
 494	 */
 495	put_device(&found_target->dev);
 496	/*
 497	 * length of time is irrelevant here, we just want to yield the CPU
 498	 * for a tick to avoid busy waiting for the target to die.
 499	 */
 500	msleep(1);
 501	goto retry;
 502}
 503
 504/**
 505 * scsi_target_reap - check to see if target is in use and destroy if not
 506 * @starget: target to be checked
 507 *
 508 * This is used after removing a LUN or doing a last put of the target
 509 * it checks atomically that nothing is using the target and removes
 510 * it if so.
 511 */
 512void scsi_target_reap(struct scsi_target *starget)
 513{
 514	/*
 515	 * serious problem if this triggers: STARGET_DEL is only set in the if
 516	 * the reap_ref drops to zero, so we're trying to do another final put
 517	 * on an already released kref
 518	 */
 519	BUG_ON(starget->state == STARGET_DEL);
 520	scsi_target_reap_ref_put(starget);
 521}
 522
 523/**
 524 * scsi_sanitize_inquiry_string - remove non-graphical chars from an
 525 *                                INQUIRY result string
 526 * @s: INQUIRY result string to sanitize
 527 * @len: length of the string
 528 *
 529 * Description:
 530 *	The SCSI spec says that INQUIRY vendor, product, and revision
 531 *	strings must consist entirely of graphic ASCII characters,
 532 *	padded on the right with spaces.  Since not all devices obey
 533 *	this rule, we will replace non-graphic or non-ASCII characters
 534 *	with spaces.  Exception: a NUL character is interpreted as a
 535 *	string terminator, so all the following characters are set to
 536 *	spaces.
 537 **/
 538void scsi_sanitize_inquiry_string(unsigned char *s, int len)
 539{
 540	int terminated = 0;
 541
 542	for (; len > 0; (--len, ++s)) {
 543		if (*s == 0)
 544			terminated = 1;
 545		if (terminated || *s < 0x20 || *s > 0x7e)
 546			*s = ' ';
 547	}
 548}
 549EXPORT_SYMBOL(scsi_sanitize_inquiry_string);
 550
 551/**
 552 * scsi_probe_lun - probe a single LUN using a SCSI INQUIRY
 553 * @sdev:	scsi_device to probe
 554 * @inq_result:	area to store the INQUIRY result
 555 * @result_len: len of inq_result
 556 * @bflags:	store any bflags found here
 557 *
 558 * Description:
 559 *     Probe the lun associated with @req using a standard SCSI INQUIRY;
 560 *
 561 *     If the INQUIRY is successful, zero is returned and the
 562 *     INQUIRY data is in @inq_result; the scsi_level and INQUIRY length
 563 *     are copied to the scsi_device any flags value is stored in *@bflags.
 564 **/
 565static int scsi_probe_lun(struct scsi_device *sdev, unsigned char *inq_result,
 566			  int result_len, int *bflags)
 567{
 568	unsigned char scsi_cmd[MAX_COMMAND_SIZE];
 569	int first_inquiry_len, try_inquiry_len, next_inquiry_len;
 570	int response_len = 0;
 571	int pass, count, result;
 572	struct scsi_sense_hdr sshdr;
 573
 574	*bflags = 0;
 575
 576	/* Perform up to 3 passes.  The first pass uses a conservative
 577	 * transfer length of 36 unless sdev->inquiry_len specifies a
 578	 * different value. */
 579	first_inquiry_len = sdev->inquiry_len ? sdev->inquiry_len : 36;
 580	try_inquiry_len = first_inquiry_len;
 581	pass = 1;
 582
 583 next_pass:
 584	SCSI_LOG_SCAN_BUS(3, sdev_printk(KERN_INFO, sdev,
 585				"scsi scan: INQUIRY pass %d length %d\n",
 586				pass, try_inquiry_len));
 587
 588	/* Each pass gets up to three chances to ignore Unit Attention */
 589	for (count = 0; count < 3; ++count) {
 590		int resid;
 591
 592		memset(scsi_cmd, 0, 6);
 593		scsi_cmd[0] = INQUIRY;
 594		scsi_cmd[4] = (unsigned char) try_inquiry_len;
 595
 596		memset(inq_result, 0, try_inquiry_len);
 597
 598		result = scsi_execute_req(sdev,  scsi_cmd, DMA_FROM_DEVICE,
 599					  inq_result, try_inquiry_len, &sshdr,
 600					  HZ / 2 + HZ * scsi_inq_timeout, 3,
 601					  &resid);
 602
 603		SCSI_LOG_SCAN_BUS(3, sdev_printk(KERN_INFO, sdev,
 604				"scsi scan: INQUIRY %s with code 0x%x\n",
 605				result ? "failed" : "successful", result));
 606
 607		if (result) {
 608			/*
 609			 * not-ready to ready transition [asc/ascq=0x28/0x0]
 610			 * or power-on, reset [asc/ascq=0x29/0x0], continue.
 611			 * INQUIRY should not yield UNIT_ATTENTION
 612			 * but many buggy devices do so anyway. 
 613			 */
 614			if ((driver_byte(result) & DRIVER_SENSE) &&
 615			    scsi_sense_valid(&sshdr)) {
 616				if ((sshdr.sense_key == UNIT_ATTENTION) &&
 617				    ((sshdr.asc == 0x28) ||
 618				     (sshdr.asc == 0x29)) &&
 619				    (sshdr.ascq == 0))
 620					continue;
 621			}
 622		} else {
 623			/*
 624			 * if nothing was transferred, we try
 625			 * again. It's a workaround for some USB
 626			 * devices.
 627			 */
 628			if (resid == try_inquiry_len)
 629				continue;
 630		}
 631		break;
 632	}
 633
 634	if (result == 0) {
 635		scsi_sanitize_inquiry_string(&inq_result[8], 8);
 636		scsi_sanitize_inquiry_string(&inq_result[16], 16);
 637		scsi_sanitize_inquiry_string(&inq_result[32], 4);
 638
 639		response_len = inq_result[4] + 5;
 640		if (response_len > 255)
 641			response_len = first_inquiry_len;	/* sanity */
 642
 643		/*
 644		 * Get any flags for this device.
 645		 *
 646		 * XXX add a bflags to scsi_device, and replace the
 647		 * corresponding bit fields in scsi_device, so bflags
 648		 * need not be passed as an argument.
 649		 */
 650		*bflags = scsi_get_device_flags(sdev, &inq_result[8],
 651				&inq_result[16]);
 652
 653		/* When the first pass succeeds we gain information about
 654		 * what larger transfer lengths might work. */
 655		if (pass == 1) {
 656			if (BLIST_INQUIRY_36 & *bflags)
 657				next_inquiry_len = 36;
 658			else if (BLIST_INQUIRY_58 & *bflags)
 659				next_inquiry_len = 58;
 660			else if (sdev->inquiry_len)
 661				next_inquiry_len = sdev->inquiry_len;
 662			else
 663				next_inquiry_len = response_len;
 664
 665			/* If more data is available perform the second pass */
 666			if (next_inquiry_len > try_inquiry_len) {
 667				try_inquiry_len = next_inquiry_len;
 668				pass = 2;
 669				goto next_pass;
 670			}
 671		}
 672
 673	} else if (pass == 2) {
 674		sdev_printk(KERN_INFO, sdev,
 675			    "scsi scan: %d byte inquiry failed.  "
 676			    "Consider BLIST_INQUIRY_36 for this device\n",
 677			    try_inquiry_len);
 678
 679		/* If this pass failed, the third pass goes back and transfers
 680		 * the same amount as we successfully got in the first pass. */
 681		try_inquiry_len = first_inquiry_len;
 682		pass = 3;
 683		goto next_pass;
 684	}
 685
 686	/* If the last transfer attempt got an error, assume the
 687	 * peripheral doesn't exist or is dead. */
 688	if (result)
 689		return -EIO;
 690
 691	/* Don't report any more data than the device says is valid */
 692	sdev->inquiry_len = min(try_inquiry_len, response_len);
 693
 694	/*
 695	 * XXX Abort if the response length is less than 36? If less than
 696	 * 32, the lookup of the device flags (above) could be invalid,
 697	 * and it would be possible to take an incorrect action - we do
 698	 * not want to hang because of a short INQUIRY. On the flip side,
 699	 * if the device is spun down or becoming ready (and so it gives a
 700	 * short INQUIRY), an abort here prevents any further use of the
 701	 * device, including spin up.
 702	 *
 703	 * On the whole, the best approach seems to be to assume the first
 704	 * 36 bytes are valid no matter what the device says.  That's
 705	 * better than copying < 36 bytes to the inquiry-result buffer
 706	 * and displaying garbage for the Vendor, Product, or Revision
 707	 * strings.
 708	 */
 709	if (sdev->inquiry_len < 36) {
 710		if (!sdev->host->short_inquiry) {
 711			shost_printk(KERN_INFO, sdev->host,
 712				    "scsi scan: INQUIRY result too short (%d),"
 713				    " using 36\n", sdev->inquiry_len);
 714			sdev->host->short_inquiry = 1;
 715		}
 716		sdev->inquiry_len = 36;
 717	}
 718
 719	/*
 720	 * Related to the above issue:
 721	 *
 722	 * XXX Devices (disk or all?) should be sent a TEST UNIT READY,
 723	 * and if not ready, sent a START_STOP to start (maybe spin up) and
 724	 * then send the INQUIRY again, since the INQUIRY can change after
 725	 * a device is initialized.
 726	 *
 727	 * Ideally, start a device if explicitly asked to do so.  This
 728	 * assumes that a device is spun up on power on, spun down on
 729	 * request, and then spun up on request.
 730	 */
 731
 732	/*
 733	 * The scanning code needs to know the scsi_level, even if no
 734	 * device is attached at LUN 0 (SCSI_SCAN_TARGET_PRESENT) so
 735	 * non-zero LUNs can be scanned.
 736	 */
 737	sdev->scsi_level = inq_result[2] & 0x07;
 738	if (sdev->scsi_level >= 2 ||
 739	    (sdev->scsi_level == 1 && (inq_result[3] & 0x0f) == 1))
 740		sdev->scsi_level++;
 741	sdev->sdev_target->scsi_level = sdev->scsi_level;
 742
 743	/*
 744	 * If SCSI-2 or lower, and if the transport requires it,
 745	 * store the LUN value in CDB[1].
 746	 */
 747	sdev->lun_in_cdb = 0;
 748	if (sdev->scsi_level <= SCSI_2 &&
 749	    sdev->scsi_level != SCSI_UNKNOWN &&
 750	    !sdev->host->no_scsi2_lun_in_cdb)
 751		sdev->lun_in_cdb = 1;
 752
 753	return 0;
 754}
 755
 756/**
 757 * scsi_add_lun - allocate and fully initialze a scsi_device
 758 * @sdev:	holds information to be stored in the new scsi_device
 759 * @inq_result:	holds the result of a previous INQUIRY to the LUN
 760 * @bflags:	black/white list flag
 761 * @async:	1 if this device is being scanned asynchronously
 762 *
 763 * Description:
 764 *     Initialize the scsi_device @sdev.  Optionally set fields based
 765 *     on values in *@bflags.
 766 *
 767 * Return:
 768 *     SCSI_SCAN_NO_RESPONSE: could not allocate or setup a scsi_device
 769 *     SCSI_SCAN_LUN_PRESENT: a new scsi_device was allocated and initialized
 770 **/
 771static int scsi_add_lun(struct scsi_device *sdev, unsigned char *inq_result,
 772		int *bflags, int async)
 773{
 774	int ret;
 775
 776	/*
 777	 * XXX do not save the inquiry, since it can change underneath us,
 778	 * save just vendor/model/rev.
 779	 *
 780	 * Rather than save it and have an ioctl that retrieves the saved
 781	 * value, have an ioctl that executes the same INQUIRY code used
 782	 * in scsi_probe_lun, let user level programs doing INQUIRY
 783	 * scanning run at their own risk, or supply a user level program
 784	 * that can correctly scan.
 785	 */
 786
 787	/*
 788	 * Copy at least 36 bytes of INQUIRY data, so that we don't
 789	 * dereference unallocated memory when accessing the Vendor,
 790	 * Product, and Revision strings.  Badly behaved devices may set
 791	 * the INQUIRY Additional Length byte to a small value, indicating
 792	 * these strings are invalid, but often they contain plausible data
 793	 * nonetheless.  It doesn't matter if the device sent < 36 bytes
 794	 * total, since scsi_probe_lun() initializes inq_result with 0s.
 795	 */
 796	sdev->inquiry = kmemdup(inq_result,
 797				max_t(size_t, sdev->inquiry_len, 36),
 798				GFP_ATOMIC);
 799	if (sdev->inquiry == NULL)
 800		return SCSI_SCAN_NO_RESPONSE;
 801
 802	sdev->vendor = (char *) (sdev->inquiry + 8);
 803	sdev->model = (char *) (sdev->inquiry + 16);
 804	sdev->rev = (char *) (sdev->inquiry + 32);
 805
 806	if (strncmp(sdev->vendor, "ATA     ", 8) == 0) {
 807		/*
 808		 * sata emulation layer device.  This is a hack to work around
 809		 * the SATL power management specifications which state that
 810		 * when the SATL detects the device has gone into standby
 811		 * mode, it shall respond with NOT READY.
 812		 */
 813		sdev->allow_restart = 1;
 814	}
 815
 816	if (*bflags & BLIST_ISROM) {
 817		sdev->type = TYPE_ROM;
 818		sdev->removable = 1;
 819	} else {
 820		sdev->type = (inq_result[0] & 0x1f);
 821		sdev->removable = (inq_result[1] & 0x80) >> 7;
 822
 823		/*
 824		 * some devices may respond with wrong type for
 825		 * well-known logical units. Force well-known type
 826		 * to enumerate them correctly.
 827		 */
 828		if (scsi_is_wlun(sdev->lun) && sdev->type != TYPE_WLUN) {
 829			sdev_printk(KERN_WARNING, sdev,
 830				"%s: correcting incorrect peripheral device type 0x%x for W-LUN 0x%16xhN\n",
 831				__func__, sdev->type, (unsigned int)sdev->lun);
 832			sdev->type = TYPE_WLUN;
 833		}
 834
 835	}
 836
 837	if (sdev->type == TYPE_RBC || sdev->type == TYPE_ROM) {
 838		/* RBC and MMC devices can return SCSI-3 compliance and yet
 839		 * still not support REPORT LUNS, so make them act as
 840		 * BLIST_NOREPORTLUN unless BLIST_REPORTLUN2 is
 841		 * specifically set */
 842		if ((*bflags & BLIST_REPORTLUN2) == 0)
 843			*bflags |= BLIST_NOREPORTLUN;
 844	}
 845
 846	/*
 847	 * For a peripheral qualifier (PQ) value of 1 (001b), the SCSI
 848	 * spec says: The device server is capable of supporting the
 849	 * specified peripheral device type on this logical unit. However,
 850	 * the physical device is not currently connected to this logical
 851	 * unit.
 852	 *
 853	 * The above is vague, as it implies that we could treat 001 and
 854	 * 011 the same. Stay compatible with previous code, and create a
 855	 * scsi_device for a PQ of 1
 856	 *
 857	 * Don't set the device offline here; rather let the upper
 858	 * level drivers eval the PQ to decide whether they should
 859	 * attach. So remove ((inq_result[0] >> 5) & 7) == 1 check.
 860	 */ 
 861
 862	sdev->inq_periph_qual = (inq_result[0] >> 5) & 7;
 863	sdev->lockable = sdev->removable;
 864	sdev->soft_reset = (inq_result[7] & 1) && ((inq_result[3] & 7) == 2);
 865
 866	if (sdev->scsi_level >= SCSI_3 ||
 867			(sdev->inquiry_len > 56 && inq_result[56] & 0x04))
 868		sdev->ppr = 1;
 869	if (inq_result[7] & 0x60)
 870		sdev->wdtr = 1;
 871	if (inq_result[7] & 0x10)
 872		sdev->sdtr = 1;
 873
 874	sdev_printk(KERN_NOTICE, sdev, "%s %.8s %.16s %.4s PQ: %d "
 875			"ANSI: %d%s\n", scsi_device_type(sdev->type),
 876			sdev->vendor, sdev->model, sdev->rev,
 877			sdev->inq_periph_qual, inq_result[2] & 0x07,
 878			(inq_result[3] & 0x0f) == 1 ? " CCS" : "");
 879
 880	if ((sdev->scsi_level >= SCSI_2) && (inq_result[7] & 2) &&
 881	    !(*bflags & BLIST_NOTQ)) {
 882		sdev->tagged_supported = 1;
 883		sdev->simple_tags = 1;
 884	}
 885
 886	/*
 887	 * Some devices (Texel CD ROM drives) have handshaking problems
 888	 * when used with the Seagate controllers. borken is initialized
 889	 * to 1, and then set it to 0 here.
 890	 */
 891	if ((*bflags & BLIST_BORKEN) == 0)
 892		sdev->borken = 0;
 893
 894	if (*bflags & BLIST_NO_ULD_ATTACH)
 895		sdev->no_uld_attach = 1;
 896
 897	/*
 898	 * Apparently some really broken devices (contrary to the SCSI
 899	 * standards) need to be selected without asserting ATN
 900	 */
 901	if (*bflags & BLIST_SELECT_NO_ATN)
 902		sdev->select_no_atn = 1;
 903
 904	/*
 905	 * Maximum 512 sector transfer length
 906	 * broken RA4x00 Compaq Disk Array
 907	 */
 908	if (*bflags & BLIST_MAX_512)
 909		blk_queue_max_hw_sectors(sdev->request_queue, 512);
 910	/*
 911	 * Max 1024 sector transfer length for targets that report incorrect
 912	 * max/optimal lengths and relied on the old block layer safe default
 913	 */
 914	else if (*bflags & BLIST_MAX_1024)
 915		blk_queue_max_hw_sectors(sdev->request_queue, 1024);
 916
 917	/*
 918	 * Some devices may not want to have a start command automatically
 919	 * issued when a device is added.
 920	 */
 921	if (*bflags & BLIST_NOSTARTONADD)
 922		sdev->no_start_on_add = 1;
 923
 924	if (*bflags & BLIST_SINGLELUN)
 925		scsi_target(sdev)->single_lun = 1;
 926
 927	sdev->use_10_for_rw = 1;
 928
 929	if (*bflags & BLIST_MS_SKIP_PAGE_08)
 930		sdev->skip_ms_page_8 = 1;
 931
 932	if (*bflags & BLIST_MS_SKIP_PAGE_3F)
 933		sdev->skip_ms_page_3f = 1;
 934
 935	if (*bflags & BLIST_USE_10_BYTE_MS)
 936		sdev->use_10_for_ms = 1;
 937
 938	/* some devices don't like REPORT SUPPORTED OPERATION CODES
 939	 * and will simply timeout causing sd_mod init to take a very
 940	 * very long time */
 941	if (*bflags & BLIST_NO_RSOC)
 942		sdev->no_report_opcodes = 1;
 943
 944	/* set the device running here so that slave configure
 945	 * may do I/O */
 
 946	ret = scsi_device_set_state(sdev, SDEV_RUNNING);
 947	if (ret) {
 948		ret = scsi_device_set_state(sdev, SDEV_BLOCK);
 
 949
 950		if (ret) {
 951			sdev_printk(KERN_ERR, sdev,
 952				    "in wrong state %s to complete scan\n",
 953				    scsi_device_state_name(sdev->sdev_state));
 954			return SCSI_SCAN_NO_RESPONSE;
 955		}
 956	}
 957
 958	if (*bflags & BLIST_MS_192_BYTES_FOR_3F)
 959		sdev->use_192_bytes_for_3f = 1;
 960
 961	if (*bflags & BLIST_NOT_LOCKABLE)
 962		sdev->lockable = 0;
 963
 964	if (*bflags & BLIST_RETRY_HWERROR)
 965		sdev->retry_hwerror = 1;
 966
 967	if (*bflags & BLIST_NO_DIF)
 968		sdev->no_dif = 1;
 969
 970	if (*bflags & BLIST_SYNC_ALUA)
 971		sdev->synchronous_alua = 1;
 972
 973	sdev->eh_timeout = SCSI_DEFAULT_EH_TIMEOUT;
 974
 975	if (*bflags & BLIST_TRY_VPD_PAGES)
 976		sdev->try_vpd_pages = 1;
 977	else if (*bflags & BLIST_SKIP_VPD_PAGES)
 978		sdev->skip_vpd_pages = 1;
 979
 980	transport_configure_device(&sdev->sdev_gendev);
 981
 982	if (sdev->host->hostt->slave_configure) {
 983		ret = sdev->host->hostt->slave_configure(sdev);
 984		if (ret) {
 985			/*
 986			 * if LLDD reports slave not present, don't clutter
 987			 * console with alloc failure messages
 988			 */
 989			if (ret != -ENXIO) {
 990				sdev_printk(KERN_ERR, sdev,
 991					"failed to configure device\n");
 992			}
 993			return SCSI_SCAN_NO_RESPONSE;
 994		}
 995	}
 996
 997	if (sdev->scsi_level >= SCSI_3)
 998		scsi_attach_vpd(sdev);
 999
1000	sdev->max_queue_depth = sdev->queue_depth;
 
1001
1002	/*
1003	 * Ok, the device is now all set up, we can
1004	 * register it and tell the rest of the kernel
1005	 * about it.
1006	 */
1007	if (!async && scsi_sysfs_add_sdev(sdev) != 0)
1008		return SCSI_SCAN_NO_RESPONSE;
1009
1010	return SCSI_SCAN_LUN_PRESENT;
1011}
1012
1013#ifdef CONFIG_SCSI_LOGGING
1014/** 
1015 * scsi_inq_str - print INQUIRY data from min to max index, strip trailing whitespace
1016 * @buf:   Output buffer with at least end-first+1 bytes of space
1017 * @inq:   Inquiry buffer (input)
1018 * @first: Offset of string into inq
1019 * @end:   Index after last character in inq
1020 */
1021static unsigned char *scsi_inq_str(unsigned char *buf, unsigned char *inq,
1022				   unsigned first, unsigned end)
1023{
1024	unsigned term = 0, idx;
1025
1026	for (idx = 0; idx + first < end && idx + first < inq[4] + 5; idx++) {
1027		if (inq[idx+first] > ' ') {
1028			buf[idx] = inq[idx+first];
1029			term = idx+1;
1030		} else {
1031			buf[idx] = ' ';
1032		}
1033	}
1034	buf[term] = 0;
1035	return buf;
1036}
1037#endif
1038
1039/**
1040 * scsi_probe_and_add_lun - probe a LUN, if a LUN is found add it
1041 * @starget:	pointer to target device structure
1042 * @lun:	LUN of target device
1043 * @bflagsp:	store bflags here if not NULL
1044 * @sdevp:	probe the LUN corresponding to this scsi_device
1045 * @rescan:     if not equal to SCSI_SCAN_INITIAL skip some code only
1046 *              needed on first scan
1047 * @hostdata:	passed to scsi_alloc_sdev()
1048 *
1049 * Description:
1050 *     Call scsi_probe_lun, if a LUN with an attached device is found,
1051 *     allocate and set it up by calling scsi_add_lun.
1052 *
1053 * Return:
1054 *     SCSI_SCAN_NO_RESPONSE: could not allocate or setup a scsi_device
1055 *     SCSI_SCAN_TARGET_PRESENT: target responded, but no device is
 
1056 *         attached at the LUN
1057 *     SCSI_SCAN_LUN_PRESENT: a new scsi_device was allocated and initialized
1058 **/
1059static int scsi_probe_and_add_lun(struct scsi_target *starget,
1060				  u64 lun, int *bflagsp,
1061				  struct scsi_device **sdevp,
1062				  enum scsi_scan_mode rescan,
1063				  void *hostdata)
1064{
1065	struct scsi_device *sdev;
1066	unsigned char *result;
1067	int bflags, res = SCSI_SCAN_NO_RESPONSE, result_len = 256;
 
1068	struct Scsi_Host *shost = dev_to_shost(starget->dev.parent);
1069
1070	/*
1071	 * The rescan flag is used as an optimization, the first scan of a
1072	 * host adapter calls into here with rescan == 0.
1073	 */
1074	sdev = scsi_device_lookup_by_target(starget, lun);
1075	if (sdev) {
1076		if (rescan != SCSI_SCAN_INITIAL || !scsi_device_created(sdev)) {
1077			SCSI_LOG_SCAN_BUS(3, sdev_printk(KERN_INFO, sdev,
1078				"scsi scan: device exists on %s\n",
1079				dev_name(&sdev->sdev_gendev)));
1080			if (sdevp)
1081				*sdevp = sdev;
1082			else
1083				scsi_device_put(sdev);
1084
1085			if (bflagsp)
1086				*bflagsp = scsi_get_device_flags(sdev,
1087								 sdev->vendor,
1088								 sdev->model);
1089			return SCSI_SCAN_LUN_PRESENT;
1090		}
1091		scsi_device_put(sdev);
1092	} else
1093		sdev = scsi_alloc_sdev(starget, lun, hostdata);
1094	if (!sdev)
1095		goto out;
1096
1097	result = kmalloc(result_len, GFP_ATOMIC |
1098			((shost->unchecked_isa_dma) ? __GFP_DMA : 0));
1099	if (!result)
1100		goto out_free_sdev;
1101
1102	if (scsi_probe_lun(sdev, result, result_len, &bflags))
1103		goto out_free_result;
1104
1105	if (bflagsp)
1106		*bflagsp = bflags;
1107	/*
1108	 * result contains valid SCSI INQUIRY data.
1109	 */
1110	if (((result[0] >> 5) == 3) && !(bflags & BLIST_ATTACH_PQ3)) {
1111		/*
1112		 * For a Peripheral qualifier 3 (011b), the SCSI
1113		 * spec says: The device server is not capable of
1114		 * supporting a physical device on this logical
1115		 * unit.
1116		 *
1117		 * For disks, this implies that there is no
1118		 * logical disk configured at sdev->lun, but there
1119		 * is a target id responding.
1120		 */
1121		SCSI_LOG_SCAN_BUS(2, sdev_printk(KERN_INFO, sdev, "scsi scan:"
1122				   " peripheral qualifier of 3, device not"
1123				   " added\n"))
1124		if (lun == 0) {
1125			SCSI_LOG_SCAN_BUS(1, {
1126				unsigned char vend[9];
1127				unsigned char mod[17];
1128
1129				sdev_printk(KERN_INFO, sdev,
1130					"scsi scan: consider passing scsi_mod."
1131					"dev_flags=%s:%s:0x240 or 0x1000240\n",
1132					scsi_inq_str(vend, result, 8, 16),
1133					scsi_inq_str(mod, result, 16, 32));
1134			});
1135
1136		}
1137
1138		res = SCSI_SCAN_TARGET_PRESENT;
1139		goto out_free_result;
1140	}
1141
1142	/*
1143	 * Some targets may set slight variations of PQ and PDT to signal
1144	 * that no LUN is present, so don't add sdev in these cases.
1145	 * Two specific examples are:
1146	 * 1) NetApp targets: return PQ=1, PDT=0x1f
1147	 * 2) USB UFI: returns PDT=0x1f, with the PQ bits being "reserved"
1148	 *    in the UFI 1.0 spec (we cannot rely on reserved bits).
1149	 *
1150	 * References:
1151	 * 1) SCSI SPC-3, pp. 145-146
1152	 * PQ=1: "A peripheral device having the specified peripheral
1153	 * device type is not connected to this logical unit. However, the
1154	 * device server is capable of supporting the specified peripheral
1155	 * device type on this logical unit."
1156	 * PDT=0x1f: "Unknown or no device type"
1157	 * 2) USB UFI 1.0, p. 20
1158	 * PDT=00h Direct-access device (floppy)
1159	 * PDT=1Fh none (no FDD connected to the requested logical unit)
1160	 */
1161	if (((result[0] >> 5) == 1 || starget->pdt_1f_for_no_lun) &&
1162	    (result[0] & 0x1f) == 0x1f &&
1163	    !scsi_is_wlun(lun)) {
1164		SCSI_LOG_SCAN_BUS(3, sdev_printk(KERN_INFO, sdev,
1165					"scsi scan: peripheral device type"
1166					" of 31, no device added\n"));
1167		res = SCSI_SCAN_TARGET_PRESENT;
1168		goto out_free_result;
1169	}
1170
1171	res = scsi_add_lun(sdev, result, &bflags, shost->async_scan);
1172	if (res == SCSI_SCAN_LUN_PRESENT) {
1173		if (bflags & BLIST_KEY) {
1174			sdev->lockable = 0;
1175			scsi_unlock_floptical(sdev, result);
1176		}
1177	}
1178
1179 out_free_result:
1180	kfree(result);
1181 out_free_sdev:
1182	if (res == SCSI_SCAN_LUN_PRESENT) {
1183		if (sdevp) {
1184			if (scsi_device_get(sdev) == 0) {
1185				*sdevp = sdev;
1186			} else {
1187				__scsi_remove_device(sdev);
1188				res = SCSI_SCAN_NO_RESPONSE;
1189			}
1190		}
1191	} else
1192		__scsi_remove_device(sdev);
1193 out:
1194	return res;
1195}
1196
1197/**
1198 * scsi_sequential_lun_scan - sequentially scan a SCSI target
1199 * @starget:	pointer to target structure to scan
1200 * @bflags:	black/white list flag for LUN 0
1201 * @scsi_level: Which version of the standard does this device adhere to
1202 * @rescan:     passed to scsi_probe_add_lun()
1203 *
1204 * Description:
1205 *     Generally, scan from LUN 1 (LUN 0 is assumed to already have been
1206 *     scanned) to some maximum lun until a LUN is found with no device
1207 *     attached. Use the bflags to figure out any oddities.
1208 *
1209 *     Modifies sdevscan->lun.
1210 **/
1211static void scsi_sequential_lun_scan(struct scsi_target *starget,
1212				     int bflags, int scsi_level,
1213				     enum scsi_scan_mode rescan)
1214{
1215	uint max_dev_lun;
1216	u64 sparse_lun, lun;
1217	struct Scsi_Host *shost = dev_to_shost(starget->dev.parent);
1218
1219	SCSI_LOG_SCAN_BUS(3, starget_printk(KERN_INFO, starget,
1220		"scsi scan: Sequential scan\n"));
1221
1222	max_dev_lun = min(max_scsi_luns, shost->max_lun);
1223	/*
1224	 * If this device is known to support sparse multiple units,
1225	 * override the other settings, and scan all of them. Normally,
1226	 * SCSI-3 devices should be scanned via the REPORT LUNS.
1227	 */
1228	if (bflags & BLIST_SPARSELUN) {
1229		max_dev_lun = shost->max_lun;
1230		sparse_lun = 1;
1231	} else
1232		sparse_lun = 0;
1233
1234	/*
1235	 * If less than SCSI_1_CCS, and no special lun scanning, stop
1236	 * scanning; this matches 2.4 behaviour, but could just be a bug
1237	 * (to continue scanning a SCSI_1_CCS device).
1238	 *
1239	 * This test is broken.  We might not have any device on lun0 for
1240	 * a sparselun device, and if that's the case then how would we
1241	 * know the real scsi_level, eh?  It might make sense to just not
1242	 * scan any SCSI_1 device for non-0 luns, but that check would best
1243	 * go into scsi_alloc_sdev() and just have it return null when asked
1244	 * to alloc an sdev for lun > 0 on an already found SCSI_1 device.
1245	 *
1246	if ((sdevscan->scsi_level < SCSI_1_CCS) &&
1247	    ((bflags & (BLIST_FORCELUN | BLIST_SPARSELUN | BLIST_MAX5LUN))
1248	     == 0))
1249		return;
1250	 */
1251	/*
1252	 * If this device is known to support multiple units, override
1253	 * the other settings, and scan all of them.
1254	 */
1255	if (bflags & BLIST_FORCELUN)
1256		max_dev_lun = shost->max_lun;
1257	/*
1258	 * REGAL CDC-4X: avoid hang after LUN 4
1259	 */
1260	if (bflags & BLIST_MAX5LUN)
1261		max_dev_lun = min(5U, max_dev_lun);
1262	/*
1263	 * Do not scan SCSI-2 or lower device past LUN 7, unless
1264	 * BLIST_LARGELUN.
1265	 */
1266	if (scsi_level < SCSI_3 && !(bflags & BLIST_LARGELUN))
1267		max_dev_lun = min(8U, max_dev_lun);
1268
1269	/*
1270	 * Stop scanning at 255 unless BLIST_SCSI3LUN
1271	 */
1272	if (!(bflags & BLIST_SCSI3LUN))
1273		max_dev_lun = min(256U, max_dev_lun);
1274
1275	/*
1276	 * We have already scanned LUN 0, so start at LUN 1. Keep scanning
1277	 * until we reach the max, or no LUN is found and we are not
1278	 * sparse_lun.
1279	 */
1280	for (lun = 1; lun < max_dev_lun; ++lun)
1281		if ((scsi_probe_and_add_lun(starget, lun, NULL, NULL, rescan,
1282					    NULL) != SCSI_SCAN_LUN_PRESENT) &&
1283		    !sparse_lun)
1284			return;
1285}
1286
1287/**
1288 * scsi_report_lun_scan - Scan using SCSI REPORT LUN results
1289 * @starget: which target
1290 * @bflags: Zero or a mix of BLIST_NOLUN, BLIST_REPORTLUN2, or BLIST_NOREPORTLUN
1291 * @rescan: nonzero if we can skip code only needed on first scan
1292 *
1293 * Description:
1294 *   Fast scanning for modern (SCSI-3) devices by sending a REPORT LUN command.
1295 *   Scan the resulting list of LUNs by calling scsi_probe_and_add_lun.
1296 *
1297 *   If BLINK_REPORTLUN2 is set, scan a target that supports more than 8
1298 *   LUNs even if it's older than SCSI-3.
1299 *   If BLIST_NOREPORTLUN is set, return 1 always.
1300 *   If BLIST_NOLUN is set, return 0 always.
1301 *   If starget->no_report_luns is set, return 1 always.
1302 *
1303 * Return:
1304 *     0: scan completed (or no memory, so further scanning is futile)
1305 *     1: could not scan with REPORT LUN
1306 **/
1307static int scsi_report_lun_scan(struct scsi_target *starget, int bflags,
1308				enum scsi_scan_mode rescan)
1309{
1310	unsigned char scsi_cmd[MAX_COMMAND_SIZE];
1311	unsigned int length;
1312	u64 lun;
1313	unsigned int num_luns;
1314	unsigned int retries;
1315	int result;
1316	struct scsi_lun *lunp, *lun_data;
1317	struct scsi_sense_hdr sshdr;
1318	struct scsi_device *sdev;
1319	struct Scsi_Host *shost = dev_to_shost(&starget->dev);
1320	int ret = 0;
1321
1322	/*
1323	 * Only support SCSI-3 and up devices if BLIST_NOREPORTLUN is not set.
1324	 * Also allow SCSI-2 if BLIST_REPORTLUN2 is set and host adapter does
1325	 * support more than 8 LUNs.
1326	 * Don't attempt if the target doesn't support REPORT LUNS.
1327	 */
1328	if (bflags & BLIST_NOREPORTLUN)
1329		return 1;
1330	if (starget->scsi_level < SCSI_2 &&
1331	    starget->scsi_level != SCSI_UNKNOWN)
1332		return 1;
1333	if (starget->scsi_level < SCSI_3 &&
1334	    (!(bflags & BLIST_REPORTLUN2) || shost->max_lun <= 8))
1335		return 1;
1336	if (bflags & BLIST_NOLUN)
1337		return 0;
1338	if (starget->no_report_luns)
1339		return 1;
1340
1341	if (!(sdev = scsi_device_lookup_by_target(starget, 0))) {
1342		sdev = scsi_alloc_sdev(starget, 0, NULL);
1343		if (!sdev)
1344			return 0;
1345		if (scsi_device_get(sdev)) {
1346			__scsi_remove_device(sdev);
1347			return 0;
1348		}
1349	}
1350
1351	/*
1352	 * Allocate enough to hold the header (the same size as one scsi_lun)
1353	 * plus the number of luns we are requesting.  511 was the default
1354	 * value of the now removed max_report_luns parameter.
1355	 */
1356	length = (511 + 1) * sizeof(struct scsi_lun);
1357retry:
1358	lun_data = kmalloc(length, GFP_KERNEL |
1359			   (sdev->host->unchecked_isa_dma ? __GFP_DMA : 0));
1360	if (!lun_data) {
1361		printk(ALLOC_FAILURE_MSG, __func__);
1362		goto out;
1363	}
1364
1365	scsi_cmd[0] = REPORT_LUNS;
1366
1367	/*
1368	 * bytes 1 - 5: reserved, set to zero.
1369	 */
1370	memset(&scsi_cmd[1], 0, 5);
1371
1372	/*
1373	 * bytes 6 - 9: length of the command.
1374	 */
1375	put_unaligned_be32(length, &scsi_cmd[6]);
1376
1377	scsi_cmd[10] = 0;	/* reserved */
1378	scsi_cmd[11] = 0;	/* control */
1379
1380	/*
1381	 * We can get a UNIT ATTENTION, for example a power on/reset, so
1382	 * retry a few times (like sd.c does for TEST UNIT READY).
1383	 * Experience shows some combinations of adapter/devices get at
1384	 * least two power on/resets.
1385	 *
1386	 * Illegal requests (for devices that do not support REPORT LUNS)
1387	 * should come through as a check condition, and will not generate
1388	 * a retry.
1389	 */
1390	for (retries = 0; retries < 3; retries++) {
1391		SCSI_LOG_SCAN_BUS(3, sdev_printk (KERN_INFO, sdev,
1392				"scsi scan: Sending REPORT LUNS to (try %d)\n",
1393				retries));
1394
1395		result = scsi_execute_req(sdev, scsi_cmd, DMA_FROM_DEVICE,
1396					  lun_data, length, &sshdr,
1397					  SCSI_REPORT_LUNS_TIMEOUT, 3, NULL);
1398
1399		SCSI_LOG_SCAN_BUS(3, sdev_printk (KERN_INFO, sdev,
1400				"scsi scan: REPORT LUNS"
1401				" %s (try %d) result 0x%x\n",
1402				result ?  "failed" : "successful",
1403				retries, result));
1404		if (result == 0)
1405			break;
1406		else if (scsi_sense_valid(&sshdr)) {
1407			if (sshdr.sense_key != UNIT_ATTENTION)
1408				break;
1409		}
1410	}
1411
1412	if (result) {
1413		/*
1414		 * The device probably does not support a REPORT LUN command
1415		 */
1416		ret = 1;
1417		goto out_err;
1418	}
1419
1420	/*
1421	 * Get the length from the first four bytes of lun_data.
1422	 */
1423	if (get_unaligned_be32(lun_data->scsi_lun) +
1424	    sizeof(struct scsi_lun) > length) {
1425		length = get_unaligned_be32(lun_data->scsi_lun) +
1426			 sizeof(struct scsi_lun);
1427		kfree(lun_data);
1428		goto retry;
1429	}
1430	length = get_unaligned_be32(lun_data->scsi_lun);
1431
1432	num_luns = (length / sizeof(struct scsi_lun));
1433
1434	SCSI_LOG_SCAN_BUS(3, sdev_printk (KERN_INFO, sdev,
1435		"scsi scan: REPORT LUN scan\n"));
1436
1437	/*
1438	 * Scan the luns in lun_data. The entry at offset 0 is really
1439	 * the header, so start at 1 and go up to and including num_luns.
1440	 */
1441	for (lunp = &lun_data[1]; lunp <= &lun_data[num_luns]; lunp++) {
1442		lun = scsilun_to_int(lunp);
1443
1444		if (lun > sdev->host->max_lun) {
1445			sdev_printk(KERN_WARNING, sdev,
1446				    "lun%llu has a LUN larger than"
1447				    " allowed by the host adapter\n", lun);
1448		} else {
1449			int res;
1450
1451			res = scsi_probe_and_add_lun(starget,
1452				lun, NULL, NULL, rescan, NULL);
1453			if (res == SCSI_SCAN_NO_RESPONSE) {
1454				/*
1455				 * Got some results, but now none, abort.
1456				 */
1457				sdev_printk(KERN_ERR, sdev,
1458					"Unexpected response"
1459					" from lun %llu while scanning, scan"
1460					" aborted\n", (unsigned long long)lun);
1461				break;
1462			}
1463		}
1464	}
1465
1466 out_err:
1467	kfree(lun_data);
1468 out:
1469	if (scsi_device_created(sdev))
1470		/*
1471		 * the sdev we used didn't appear in the report luns scan
1472		 */
1473		__scsi_remove_device(sdev);
1474	scsi_device_put(sdev);
1475	return ret;
1476}
1477
1478struct scsi_device *__scsi_add_device(struct Scsi_Host *shost, uint channel,
1479				      uint id, u64 lun, void *hostdata)
1480{
1481	struct scsi_device *sdev = ERR_PTR(-ENODEV);
1482	struct device *parent = &shost->shost_gendev;
1483	struct scsi_target *starget;
1484
1485	if (strncmp(scsi_scan_type, "none", 4) == 0)
1486		return ERR_PTR(-ENODEV);
1487
1488	starget = scsi_alloc_target(parent, channel, id);
1489	if (!starget)
1490		return ERR_PTR(-ENOMEM);
1491	scsi_autopm_get_target(starget);
1492
1493	mutex_lock(&shost->scan_mutex);
1494	if (!shost->async_scan)
1495		scsi_complete_async_scans();
1496
1497	if (scsi_host_scan_allowed(shost) && scsi_autopm_get_host(shost) == 0) {
1498		scsi_probe_and_add_lun(starget, lun, NULL, &sdev, 1, hostdata);
1499		scsi_autopm_put_host(shost);
1500	}
1501	mutex_unlock(&shost->scan_mutex);
1502	scsi_autopm_put_target(starget);
1503	/*
1504	 * paired with scsi_alloc_target().  Target will be destroyed unless
1505	 * scsi_probe_and_add_lun made an underlying device visible
1506	 */
1507	scsi_target_reap(starget);
1508	put_device(&starget->dev);
1509
1510	return sdev;
1511}
1512EXPORT_SYMBOL(__scsi_add_device);
1513
1514int scsi_add_device(struct Scsi_Host *host, uint channel,
1515		    uint target, u64 lun)
1516{
1517	struct scsi_device *sdev = 
1518		__scsi_add_device(host, channel, target, lun, NULL);
1519	if (IS_ERR(sdev))
1520		return PTR_ERR(sdev);
1521
1522	scsi_device_put(sdev);
1523	return 0;
1524}
1525EXPORT_SYMBOL(scsi_add_device);
1526
1527void scsi_rescan_device(struct device *dev)
1528{
1529	struct scsi_device *sdev = to_scsi_device(dev);
1530
1531	device_lock(dev);
1532
1533	scsi_attach_vpd(sdev);
1534
1535	if (sdev->handler && sdev->handler->rescan)
1536		sdev->handler->rescan(sdev);
1537
1538	if (dev->driver && try_module_get(dev->driver->owner)) {
1539		struct scsi_driver *drv = to_scsi_driver(dev->driver);
1540
1541		if (drv->rescan)
1542			drv->rescan(dev);
1543		module_put(dev->driver->owner);
1544	}
1545	device_unlock(dev);
1546}
1547EXPORT_SYMBOL(scsi_rescan_device);
1548
1549static void __scsi_scan_target(struct device *parent, unsigned int channel,
1550		unsigned int id, u64 lun, enum scsi_scan_mode rescan)
1551{
1552	struct Scsi_Host *shost = dev_to_shost(parent);
1553	int bflags = 0;
1554	int res;
1555	struct scsi_target *starget;
1556
1557	if (shost->this_id == id)
1558		/*
1559		 * Don't scan the host adapter
1560		 */
1561		return;
1562
1563	starget = scsi_alloc_target(parent, channel, id);
1564	if (!starget)
1565		return;
1566	scsi_autopm_get_target(starget);
1567
1568	if (lun != SCAN_WILD_CARD) {
1569		/*
1570		 * Scan for a specific host/chan/id/lun.
1571		 */
1572		scsi_probe_and_add_lun(starget, lun, NULL, NULL, rescan, NULL);
1573		goto out_reap;
1574	}
1575
1576	/*
1577	 * Scan LUN 0, if there is some response, scan further. Ideally, we
1578	 * would not configure LUN 0 until all LUNs are scanned.
1579	 */
1580	res = scsi_probe_and_add_lun(starget, 0, &bflags, NULL, rescan, NULL);
1581	if (res == SCSI_SCAN_LUN_PRESENT || res == SCSI_SCAN_TARGET_PRESENT) {
1582		if (scsi_report_lun_scan(starget, bflags, rescan) != 0)
1583			/*
1584			 * The REPORT LUN did not scan the target,
1585			 * do a sequential scan.
1586			 */
1587			scsi_sequential_lun_scan(starget, bflags,
1588						 starget->scsi_level, rescan);
1589	}
1590
1591 out_reap:
1592	scsi_autopm_put_target(starget);
1593	/*
1594	 * paired with scsi_alloc_target(): determine if the target has
1595	 * any children at all and if not, nuke it
1596	 */
1597	scsi_target_reap(starget);
1598
1599	put_device(&starget->dev);
1600}
1601
1602/**
1603 * scsi_scan_target - scan a target id, possibly including all LUNs on the target.
1604 * @parent:	host to scan
1605 * @channel:	channel to scan
1606 * @id:		target id to scan
1607 * @lun:	Specific LUN to scan or SCAN_WILD_CARD
1608 * @rescan:	passed to LUN scanning routines; SCSI_SCAN_INITIAL for
1609 *              no rescan, SCSI_SCAN_RESCAN to rescan existing LUNs,
1610 *              and SCSI_SCAN_MANUAL to force scanning even if
1611 *              'scan=manual' is set.
1612 *
1613 * Description:
1614 *     Scan the target id on @parent, @channel, and @id. Scan at least LUN 0,
1615 *     and possibly all LUNs on the target id.
1616 *
1617 *     First try a REPORT LUN scan, if that does not scan the target, do a
1618 *     sequential scan of LUNs on the target id.
1619 **/
1620void scsi_scan_target(struct device *parent, unsigned int channel,
1621		      unsigned int id, u64 lun, enum scsi_scan_mode rescan)
1622{
1623	struct Scsi_Host *shost = dev_to_shost(parent);
1624
1625	if (strncmp(scsi_scan_type, "none", 4) == 0)
1626		return;
1627
1628	if (rescan != SCSI_SCAN_MANUAL &&
1629	    strncmp(scsi_scan_type, "manual", 6) == 0)
1630		return;
1631
1632	mutex_lock(&shost->scan_mutex);
1633	if (!shost->async_scan)
1634		scsi_complete_async_scans();
1635
1636	if (scsi_host_scan_allowed(shost) && scsi_autopm_get_host(shost) == 0) {
1637		__scsi_scan_target(parent, channel, id, lun, rescan);
1638		scsi_autopm_put_host(shost);
1639	}
1640	mutex_unlock(&shost->scan_mutex);
1641}
1642EXPORT_SYMBOL(scsi_scan_target);
1643
1644static void scsi_scan_channel(struct Scsi_Host *shost, unsigned int channel,
1645			      unsigned int id, u64 lun,
1646			      enum scsi_scan_mode rescan)
1647{
1648	uint order_id;
1649
1650	if (id == SCAN_WILD_CARD)
1651		for (id = 0; id < shost->max_id; ++id) {
1652			/*
1653			 * XXX adapter drivers when possible (FCP, iSCSI)
1654			 * could modify max_id to match the current max,
1655			 * not the absolute max.
1656			 *
1657			 * XXX add a shost id iterator, so for example,
1658			 * the FC ID can be the same as a target id
1659			 * without a huge overhead of sparse id's.
1660			 */
1661			if (shost->reverse_ordering)
1662				/*
1663				 * Scan from high to low id.
1664				 */
1665				order_id = shost->max_id - id - 1;
1666			else
1667				order_id = id;
1668			__scsi_scan_target(&shost->shost_gendev, channel,
1669					order_id, lun, rescan);
1670		}
1671	else
1672		__scsi_scan_target(&shost->shost_gendev, channel,
1673				id, lun, rescan);
1674}
1675
1676int scsi_scan_host_selected(struct Scsi_Host *shost, unsigned int channel,
1677			    unsigned int id, u64 lun,
1678			    enum scsi_scan_mode rescan)
1679{
1680	SCSI_LOG_SCAN_BUS(3, shost_printk (KERN_INFO, shost,
1681		"%s: <%u:%u:%llu>\n",
1682		__func__, channel, id, lun));
1683
1684	if (((channel != SCAN_WILD_CARD) && (channel > shost->max_channel)) ||
1685	    ((id != SCAN_WILD_CARD) && (id >= shost->max_id)) ||
1686	    ((lun != SCAN_WILD_CARD) && (lun >= shost->max_lun)))
1687		return -EINVAL;
1688
1689	mutex_lock(&shost->scan_mutex);
1690	if (!shost->async_scan)
1691		scsi_complete_async_scans();
1692
1693	if (scsi_host_scan_allowed(shost) && scsi_autopm_get_host(shost) == 0) {
1694		if (channel == SCAN_WILD_CARD)
1695			for (channel = 0; channel <= shost->max_channel;
1696			     channel++)
1697				scsi_scan_channel(shost, channel, id, lun,
1698						  rescan);
1699		else
1700			scsi_scan_channel(shost, channel, id, lun, rescan);
1701		scsi_autopm_put_host(shost);
1702	}
1703	mutex_unlock(&shost->scan_mutex);
1704
1705	return 0;
1706}
1707
1708static void scsi_sysfs_add_devices(struct Scsi_Host *shost)
1709{
1710	struct scsi_device *sdev;
1711	shost_for_each_device(sdev, shost) {
1712		/* target removed before the device could be added */
1713		if (sdev->sdev_state == SDEV_DEL)
1714			continue;
1715		/* If device is already visible, skip adding it to sysfs */
1716		if (sdev->is_visible)
1717			continue;
1718		if (!scsi_host_scan_allowed(shost) ||
1719		    scsi_sysfs_add_sdev(sdev) != 0)
1720			__scsi_remove_device(sdev);
1721	}
1722}
1723
1724/**
1725 * scsi_prep_async_scan - prepare for an async scan
1726 * @shost: the host which will be scanned
1727 * Returns: a cookie to be passed to scsi_finish_async_scan()
1728 *
1729 * Tells the midlayer this host is going to do an asynchronous scan.
1730 * It reserves the host's position in the scanning list and ensures
1731 * that other asynchronous scans started after this one won't affect the
1732 * ordering of the discovered devices.
1733 */
1734static struct async_scan_data *scsi_prep_async_scan(struct Scsi_Host *shost)
1735{
1736	struct async_scan_data *data;
1737	unsigned long flags;
1738
1739	if (strncmp(scsi_scan_type, "sync", 4) == 0)
1740		return NULL;
1741
1742	if (shost->async_scan) {
1743		shost_printk(KERN_DEBUG, shost, "%s called twice\n", __func__);
1744		return NULL;
1745	}
1746
1747	data = kmalloc(sizeof(*data), GFP_KERNEL);
1748	if (!data)
1749		goto err;
1750	data->shost = scsi_host_get(shost);
1751	if (!data->shost)
1752		goto err;
1753	init_completion(&data->prev_finished);
1754
1755	mutex_lock(&shost->scan_mutex);
1756	spin_lock_irqsave(shost->host_lock, flags);
1757	shost->async_scan = 1;
1758	spin_unlock_irqrestore(shost->host_lock, flags);
1759	mutex_unlock(&shost->scan_mutex);
1760
1761	spin_lock(&async_scan_lock);
1762	if (list_empty(&scanning_hosts))
1763		complete(&data->prev_finished);
1764	list_add_tail(&data->list, &scanning_hosts);
1765	spin_unlock(&async_scan_lock);
1766
1767	return data;
1768
1769 err:
1770	kfree(data);
1771	return NULL;
1772}
1773
1774/**
1775 * scsi_finish_async_scan - asynchronous scan has finished
1776 * @data: cookie returned from earlier call to scsi_prep_async_scan()
1777 *
1778 * All the devices currently attached to this host have been found.
1779 * This function announces all the devices it has found to the rest
1780 * of the system.
1781 */
1782static void scsi_finish_async_scan(struct async_scan_data *data)
1783{
1784	struct Scsi_Host *shost;
1785	unsigned long flags;
1786
1787	if (!data)
1788		return;
1789
1790	shost = data->shost;
1791
1792	mutex_lock(&shost->scan_mutex);
1793
1794	if (!shost->async_scan) {
1795		shost_printk(KERN_INFO, shost, "%s called twice\n", __func__);
1796		dump_stack();
1797		mutex_unlock(&shost->scan_mutex);
1798		return;
1799	}
1800
1801	wait_for_completion(&data->prev_finished);
1802
1803	scsi_sysfs_add_devices(shost);
1804
1805	spin_lock_irqsave(shost->host_lock, flags);
1806	shost->async_scan = 0;
1807	spin_unlock_irqrestore(shost->host_lock, flags);
1808
1809	mutex_unlock(&shost->scan_mutex);
1810
1811	spin_lock(&async_scan_lock);
1812	list_del(&data->list);
1813	if (!list_empty(&scanning_hosts)) {
1814		struct async_scan_data *next = list_entry(scanning_hosts.next,
1815				struct async_scan_data, list);
1816		complete(&next->prev_finished);
1817	}
1818	spin_unlock(&async_scan_lock);
1819
1820	scsi_autopm_put_host(shost);
1821	scsi_host_put(shost);
1822	kfree(data);
1823}
1824
1825static void do_scsi_scan_host(struct Scsi_Host *shost)
1826{
1827	if (shost->hostt->scan_finished) {
1828		unsigned long start = jiffies;
1829		if (shost->hostt->scan_start)
1830			shost->hostt->scan_start(shost);
1831
1832		while (!shost->hostt->scan_finished(shost, jiffies - start))
1833			msleep(10);
1834	} else {
1835		scsi_scan_host_selected(shost, SCAN_WILD_CARD, SCAN_WILD_CARD,
1836				SCAN_WILD_CARD, 0);
1837	}
1838}
1839
1840static void do_scan_async(void *_data, async_cookie_t c)
1841{
1842	struct async_scan_data *data = _data;
1843	struct Scsi_Host *shost = data->shost;
1844
1845	do_scsi_scan_host(shost);
1846	scsi_finish_async_scan(data);
1847}
1848
1849/**
1850 * scsi_scan_host - scan the given adapter
1851 * @shost:	adapter to scan
1852 **/
1853void scsi_scan_host(struct Scsi_Host *shost)
1854{
1855	struct async_scan_data *data;
1856
1857	if (strncmp(scsi_scan_type, "none", 4) == 0 ||
1858	    strncmp(scsi_scan_type, "manual", 6) == 0)
1859		return;
1860	if (scsi_autopm_get_host(shost) < 0)
1861		return;
1862
1863	data = scsi_prep_async_scan(shost);
1864	if (!data) {
1865		do_scsi_scan_host(shost);
1866		scsi_autopm_put_host(shost);
1867		return;
1868	}
1869
1870	/* register with the async subsystem so wait_for_device_probe()
1871	 * will flush this work
1872	 */
1873	async_schedule(do_scan_async, data);
1874
1875	/* scsi_autopm_put_host(shost) is called in scsi_finish_async_scan() */
1876}
1877EXPORT_SYMBOL(scsi_scan_host);
1878
1879void scsi_forget_host(struct Scsi_Host *shost)
1880{
1881	struct scsi_device *sdev;
1882	unsigned long flags;
1883
1884 restart:
1885	spin_lock_irqsave(shost->host_lock, flags);
1886	list_for_each_entry(sdev, &shost->__devices, siblings) {
1887		if (sdev->sdev_state == SDEV_DEL)
1888			continue;
1889		spin_unlock_irqrestore(shost->host_lock, flags);
1890		__scsi_remove_device(sdev);
1891		goto restart;
1892	}
1893	spin_unlock_irqrestore(shost->host_lock, flags);
1894}
1895
1896/**
1897 * scsi_get_host_dev - Create a scsi_device that points to the host adapter itself
1898 * @shost: Host that needs a scsi_device
1899 *
1900 * Lock status: None assumed.
1901 *
1902 * Returns:     The scsi_device or NULL
1903 *
1904 * Notes:
1905 *	Attach a single scsi_device to the Scsi_Host - this should
1906 *	be made to look like a "pseudo-device" that points to the
1907 *	HA itself.
1908 *
1909 *	Note - this device is not accessible from any high-level
1910 *	drivers (including generics), which is probably not
1911 *	optimal.  We can add hooks later to attach.
1912 */
1913struct scsi_device *scsi_get_host_dev(struct Scsi_Host *shost)
1914{
1915	struct scsi_device *sdev = NULL;
1916	struct scsi_target *starget;
1917
1918	mutex_lock(&shost->scan_mutex);
1919	if (!scsi_host_scan_allowed(shost))
1920		goto out;
1921	starget = scsi_alloc_target(&shost->shost_gendev, 0, shost->this_id);
1922	if (!starget)
1923		goto out;
1924
1925	sdev = scsi_alloc_sdev(starget, 0, NULL);
1926	if (sdev)
1927		sdev->borken = 0;
1928	else
1929		scsi_target_reap(starget);
1930	put_device(&starget->dev);
1931 out:
1932	mutex_unlock(&shost->scan_mutex);
1933	return sdev;
1934}
1935EXPORT_SYMBOL(scsi_get_host_dev);
1936
1937/**
1938 * scsi_free_host_dev - Free a scsi_device that points to the host adapter itself
1939 * @sdev: Host device to be freed
1940 *
1941 * Lock status: None assumed.
1942 *
1943 * Returns:     Nothing
1944 */
1945void scsi_free_host_dev(struct scsi_device *sdev)
1946{
1947	BUG_ON(sdev->id != sdev->host->this_id);
1948
1949	__scsi_remove_device(sdev);
1950}
1951EXPORT_SYMBOL(scsi_free_host_dev);
1952