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