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
  38#include <scsi/scsi.h>
  39#include <scsi/scsi_cmnd.h>
  40#include <scsi/scsi_device.h>
  41#include <scsi/scsi_driver.h>
  42#include <scsi/scsi_devinfo.h>
  43#include <scsi/scsi_host.h>
  44#include <scsi/scsi_transport.h>
 
  45#include <scsi/scsi_eh.h>
  46
  47#include "scsi_priv.h"
  48#include "scsi_logging.h"
  49
  50#define ALLOC_FAILURE_MSG	KERN_ERR "%s: Allocation failure during" \
  51	" SCSI scanning, some SCSI devices might not be configured\n"
  52
  53/*
  54 * Default timeout
  55 */
  56#define SCSI_TIMEOUT (2*HZ)
 
  57
  58/*
  59 * Prefix values for the SCSI id's (stored in sysfs name field)
  60 */
  61#define SCSI_UID_SER_NUM 'S'
  62#define SCSI_UID_UNKNOWN 'Z'
  63
  64/*
  65 * Return values of some of the scanning functions.
  66 *
  67 * SCSI_SCAN_NO_RESPONSE: no valid response received from the target, this
  68 * includes allocation or general failures preventing IO from being sent.
  69 *
  70 * SCSI_SCAN_TARGET_PRESENT: target responded, but no device is available
  71 * on the given LUN.
  72 *
  73 * SCSI_SCAN_LUN_PRESENT: target responded, and a device is available on a
  74 * given LUN.
  75 */
  76#define SCSI_SCAN_NO_RESPONSE		0
  77#define SCSI_SCAN_TARGET_PRESENT	1
  78#define SCSI_SCAN_LUN_PRESENT		2
  79
  80static const char *scsi_null_device_strs = "nullnullnullnull";
  81
  82#define MAX_SCSI_LUNS	512
  83
  84#ifdef CONFIG_SCSI_MULTI_LUN
  85static unsigned int max_scsi_luns = MAX_SCSI_LUNS;
  86#else
  87static unsigned int max_scsi_luns = 1;
  88#endif
  89
  90module_param_named(max_luns, max_scsi_luns, uint, S_IRUGO|S_IWUSR);
  91MODULE_PARM_DESC(max_luns,
  92		 "last scsi LUN (should be between 1 and 2^32-1)");
  93
  94#ifdef CONFIG_SCSI_SCAN_ASYNC
  95#define SCSI_SCAN_TYPE_DEFAULT "async"
  96#else
  97#define SCSI_SCAN_TYPE_DEFAULT "sync"
  98#endif
  99
 100static char scsi_scan_type[6] = SCSI_SCAN_TYPE_DEFAULT;
 101
 102module_param_string(scan, scsi_scan_type, sizeof(scsi_scan_type), S_IRUGO);
 103MODULE_PARM_DESC(scan, "sync, async or none");
 104
 105/*
 106 * max_scsi_report_luns: the maximum number of LUNS that will be
 107 * returned from the REPORT LUNS command. 8 times this value must
 108 * be allocated. In theory this could be up to an 8 byte value, but
 109 * in practice, the maximum number of LUNs suppored by any device
 110 * is about 16k.
 111 */
 112static unsigned int max_scsi_report_luns = 511;
 113
 114module_param_named(max_report_luns, max_scsi_report_luns, uint, S_IRUGO|S_IWUSR);
 115MODULE_PARM_DESC(max_report_luns,
 116		 "REPORT LUNS maximum number of LUNS received (should be"
 117		 " between 1 and 16384)");
 118
 119static unsigned int scsi_inq_timeout = SCSI_TIMEOUT/HZ + 18;
 120
 121module_param_named(inq_timeout, scsi_inq_timeout, uint, S_IRUGO|S_IWUSR);
 122MODULE_PARM_DESC(inq_timeout, 
 123		 "Timeout (in seconds) waiting for devices to answer INQUIRY."
 124		 " Default is 20. Some devices may need more; most need less.");
 125
 126/* This lock protects only this list */
 127static DEFINE_SPINLOCK(async_scan_lock);
 128static LIST_HEAD(scanning_hosts);
 129
 130struct async_scan_data {
 131	struct list_head list;
 132	struct Scsi_Host *shost;
 133	struct completion prev_finished;
 134};
 135
 136/**
 137 * scsi_complete_async_scans - Wait for asynchronous scans to complete
 138 *
 139 * When this function returns, any host which started scanning before
 140 * this function was called will have finished its scan.  Hosts which
 141 * started scanning after this function was called may or may not have
 142 * finished.
 143 */
 144int scsi_complete_async_scans(void)
 145{
 146	struct async_scan_data *data;
 147
 148	do {
 149		if (list_empty(&scanning_hosts))
 150			return 0;
 151		/* If we can't get memory immediately, that's OK.  Just
 152		 * sleep a little.  Even if we never get memory, the async
 153		 * scans will finish eventually.
 154		 */
 155		data = kmalloc(sizeof(*data), GFP_KERNEL);
 156		if (!data)
 157			msleep(1);
 158	} while (!data);
 159
 160	data->shost = NULL;
 161	init_completion(&data->prev_finished);
 162
 163	spin_lock(&async_scan_lock);
 164	/* Check that there's still somebody else on the list */
 165	if (list_empty(&scanning_hosts))
 166		goto done;
 167	list_add_tail(&data->list, &scanning_hosts);
 168	spin_unlock(&async_scan_lock);
 169
 170	printk(KERN_INFO "scsi: waiting for bus probes to complete ...\n");
 171	wait_for_completion(&data->prev_finished);
 172
 173	spin_lock(&async_scan_lock);
 174	list_del(&data->list);
 175	if (!list_empty(&scanning_hosts)) {
 176		struct async_scan_data *next = list_entry(scanning_hosts.next,
 177				struct async_scan_data, list);
 178		complete(&next->prev_finished);
 179	}
 180 done:
 181	spin_unlock(&async_scan_lock);
 182
 183	kfree(data);
 184	return 0;
 185}
 186
 187/* Only exported for the benefit of scsi_wait_scan */
 188EXPORT_SYMBOL_GPL(scsi_complete_async_scans);
 189
 190#ifndef MODULE
 191/*
 192 * For async scanning we need to wait for all the scans to complete before
 193 * trying to mount the root fs.  Otherwise non-modular drivers may not be ready
 194 * yet.
 195 */
 196late_initcall(scsi_complete_async_scans);
 197#endif
 198
 199/**
 200 * scsi_unlock_floptical - unlock device via a special MODE SENSE command
 201 * @sdev:	scsi device to send command to
 202 * @result:	area to store the result of the MODE SENSE
 203 *
 204 * Description:
 205 *     Send a vendor specific MODE SENSE (not a MODE SELECT) command.
 206 *     Called for BLIST_KEY devices.
 207 **/
 208static void scsi_unlock_floptical(struct scsi_device *sdev,
 209				  unsigned char *result)
 210{
 211	unsigned char scsi_cmd[MAX_COMMAND_SIZE];
 212
 213	printk(KERN_NOTICE "scsi: unlocking floptical drive\n");
 214	scsi_cmd[0] = MODE_SENSE;
 215	scsi_cmd[1] = 0;
 216	scsi_cmd[2] = 0x2e;
 217	scsi_cmd[3] = 0;
 218	scsi_cmd[4] = 0x2a;     /* size */
 219	scsi_cmd[5] = 0;
 220	scsi_execute_req(sdev, scsi_cmd, DMA_FROM_DEVICE, result, 0x2a, NULL,
 221			 SCSI_TIMEOUT, 3, NULL);
 222}
 223
 224/**
 225 * scsi_alloc_sdev - allocate and setup a scsi_Device
 226 * @starget: which target to allocate a &scsi_device for
 227 * @lun: which lun
 228 * @hostdata: usually NULL and set by ->slave_alloc instead
 229 *
 230 * Description:
 231 *     Allocate, initialize for io, and return a pointer to a scsi_Device.
 232 *     Stores the @shost, @channel, @id, and @lun in the scsi_Device, and
 233 *     adds scsi_Device to the appropriate list.
 234 *
 235 * Return value:
 236 *     scsi_Device pointer, or NULL on failure.
 237 **/
 238static struct scsi_device *scsi_alloc_sdev(struct scsi_target *starget,
 239					   unsigned int lun, void *hostdata)
 240{
 241	struct scsi_device *sdev;
 242	int display_failure_msg = 1, ret;
 243	struct Scsi_Host *shost = dev_to_shost(starget->dev.parent);
 244	extern void scsi_evt_thread(struct work_struct *work);
 245	extern void scsi_requeue_run_queue(struct work_struct *work);
 246
 247	sdev = kzalloc(sizeof(*sdev) + shost->transportt->device_size,
 248		       GFP_ATOMIC);
 249	if (!sdev)
 250		goto out;
 251
 252	sdev->vendor = scsi_null_device_strs;
 253	sdev->model = scsi_null_device_strs;
 254	sdev->rev = scsi_null_device_strs;
 255	sdev->host = shost;
 256	sdev->queue_ramp_up_period = SCSI_DEFAULT_RAMP_UP_PERIOD;
 257	sdev->id = starget->id;
 258	sdev->lun = lun;
 259	sdev->channel = starget->channel;
 
 260	sdev->sdev_state = SDEV_CREATED;
 261	INIT_LIST_HEAD(&sdev->siblings);
 262	INIT_LIST_HEAD(&sdev->same_target_siblings);
 263	INIT_LIST_HEAD(&sdev->cmd_list);
 264	INIT_LIST_HEAD(&sdev->starved_entry);
 265	INIT_LIST_HEAD(&sdev->event_list);
 266	spin_lock_init(&sdev->list_lock);
 
 267	INIT_WORK(&sdev->event_work, scsi_evt_thread);
 268	INIT_WORK(&sdev->requeue_work, scsi_requeue_run_queue);
 269
 270	sdev->sdev_gendev.parent = get_device(&starget->dev);
 271	sdev->sdev_target = starget;
 272
 273	/* usually NULL and set by ->slave_alloc instead */
 274	sdev->hostdata = hostdata;
 275
 276	/* if the device needs this changing, it may do so in the
 277	 * slave_configure function */
 278	sdev->max_device_blocked = SCSI_DEFAULT_DEVICE_BLOCKED;
 279
 280	/*
 281	 * Some low level driver could use device->type
 282	 */
 283	sdev->type = -1;
 284
 285	/*
 286	 * Assume that the device will have handshaking problems,
 287	 * and then fix this field later if it turns out it
 288	 * doesn't
 289	 */
 290	sdev->borken = 1;
 291
 292	sdev->request_queue = scsi_alloc_queue(sdev);
 
 
 
 293	if (!sdev->request_queue) {
 294		/* release fn is set up in scsi_sysfs_device_initialise, so
 295		 * have to free and put manually here */
 296		put_device(&starget->dev);
 297		kfree(sdev);
 298		goto out;
 299	}
 300	blk_get_queue(sdev->request_queue);
 301	sdev->request_queue->queuedata = sdev;
 302	scsi_adjust_queue_depth(sdev, 0, sdev->host->cmd_per_lun);
 
 
 
 
 
 
 
 303
 304	scsi_sysfs_device_initialize(sdev);
 305
 306	if (shost->hostt->slave_alloc) {
 307		ret = shost->hostt->slave_alloc(sdev);
 308		if (ret) {
 309			/*
 310			 * if LLDD reports slave not present, don't clutter
 311			 * console with alloc failure messages
 312			 */
 313			if (ret == -ENXIO)
 314				display_failure_msg = 0;
 315			goto out_device_destroy;
 316		}
 317	}
 318
 319	return sdev;
 320
 321out_device_destroy:
 322	scsi_device_set_state(sdev, SDEV_DEL);
 323	transport_destroy_device(&sdev->sdev_gendev);
 324	put_device(&sdev->sdev_dev);
 325	put_device(&sdev->sdev_gendev);
 326out:
 327	if (display_failure_msg)
 328		printk(ALLOC_FAILURE_MSG, __func__);
 329	return NULL;
 330}
 331
 332static void scsi_target_destroy(struct scsi_target *starget)
 333{
 334	struct device *dev = &starget->dev;
 335	struct Scsi_Host *shost = dev_to_shost(dev->parent);
 336	unsigned long flags;
 337
 
 
 338	transport_destroy_device(dev);
 339	spin_lock_irqsave(shost->host_lock, flags);
 340	if (shost->hostt->target_destroy)
 341		shost->hostt->target_destroy(starget);
 342	list_del_init(&starget->siblings);
 343	spin_unlock_irqrestore(shost->host_lock, flags);
 344	put_device(dev);
 345}
 346
 347static void scsi_target_dev_release(struct device *dev)
 348{
 349	struct device *parent = dev->parent;
 350	struct scsi_target *starget = to_scsi_target(dev);
 351
 352	kfree(starget);
 353	put_device(parent);
 354}
 355
 356static struct device_type scsi_target_type = {
 357	.name =		"scsi_target",
 358	.release =	scsi_target_dev_release,
 359};
 360
 361int scsi_is_target_device(const struct device *dev)
 362{
 363	return dev->type == &scsi_target_type;
 364}
 365EXPORT_SYMBOL(scsi_is_target_device);
 366
 367static struct scsi_target *__scsi_find_target(struct device *parent,
 368					      int channel, uint id)
 369{
 370	struct scsi_target *starget, *found_starget = NULL;
 371	struct Scsi_Host *shost = dev_to_shost(parent);
 372	/*
 373	 * Search for an existing target for this sdev.
 374	 */
 375	list_for_each_entry(starget, &shost->__targets, siblings) {
 376		if (starget->id == id &&
 377		    starget->channel == channel) {
 378			found_starget = starget;
 379			break;
 380		}
 381	}
 382	if (found_starget)
 383		get_device(&found_starget->dev);
 384
 385	return found_starget;
 386}
 387
 388/**
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 389 * scsi_alloc_target - allocate a new or find an existing target
 390 * @parent:	parent of the target (need not be a scsi host)
 391 * @channel:	target channel number (zero if no channels)
 392 * @id:		target id number
 393 *
 394 * Return an existing target if one exists, provided it hasn't already
 395 * gone into STARGET_DEL state, otherwise allocate a new target.
 396 *
 397 * The target is returned with an incremented reference, so the caller
 398 * is responsible for both reaping and doing a last put
 399 */
 400static struct scsi_target *scsi_alloc_target(struct device *parent,
 401					     int channel, uint id)
 402{
 403	struct Scsi_Host *shost = dev_to_shost(parent);
 404	struct device *dev = NULL;
 405	unsigned long flags;
 406	const int size = sizeof(struct scsi_target)
 407		+ shost->transportt->target_size;
 408	struct scsi_target *starget;
 409	struct scsi_target *found_target;
 410	int error;
 411
 412	starget = kzalloc(size, GFP_KERNEL);
 413	if (!starget) {
 414		printk(KERN_ERR "%s: allocation failure\n", __func__);
 415		return NULL;
 416	}
 417	dev = &starget->dev;
 418	device_initialize(dev);
 419	starget->reap_ref = 1;
 420	dev->parent = get_device(parent);
 421	dev_set_name(dev, "target%d:%d:%d", shost->host_no, channel, id);
 422	dev->bus = &scsi_bus_type;
 423	dev->type = &scsi_target_type;
 424	starget->id = id;
 425	starget->channel = channel;
 426	starget->can_queue = 0;
 427	INIT_LIST_HEAD(&starget->siblings);
 428	INIT_LIST_HEAD(&starget->devices);
 429	starget->state = STARGET_CREATED;
 430	starget->scsi_level = SCSI_2;
 431	starget->max_target_blocked = SCSI_DEFAULT_TARGET_BLOCKED;
 432 retry:
 433	spin_lock_irqsave(shost->host_lock, flags);
 434
 435	found_target = __scsi_find_target(parent, channel, id);
 436	if (found_target)
 437		goto found;
 438
 439	list_add_tail(&starget->siblings, &shost->__targets);
 440	spin_unlock_irqrestore(shost->host_lock, flags);
 441	/* allocate and add */
 442	transport_setup_device(dev);
 443	if (shost->hostt->target_alloc) {
 444		error = shost->hostt->target_alloc(starget);
 445
 446		if(error) {
 447			dev_printk(KERN_ERR, dev, "target allocation failed, error %d\n", error);
 448			/* don't want scsi_target_reap to do the final
 449			 * put because it will be under the host lock */
 450			scsi_target_destroy(starget);
 451			return NULL;
 452		}
 453	}
 454	get_device(dev);
 455
 456	return starget;
 457
 458 found:
 459	found_target->reap_ref++;
 
 
 
 
 
 
 460	spin_unlock_irqrestore(shost->host_lock, flags);
 461	if (found_target->state != STARGET_DEL) {
 462		put_device(dev);
 463		return found_target;
 464	}
 465	/* Unfortunately, we found a dying target; need to
 466	 * wait until it's dead before we can get a new one */
 
 
 
 
 
 
 
 467	put_device(&found_target->dev);
 468	flush_scheduled_work();
 
 
 
 
 469	goto retry;
 470}
 471
 472static void scsi_target_reap_usercontext(struct work_struct *work)
 473{
 474	struct scsi_target *starget =
 475		container_of(work, struct scsi_target, ew.work);
 476
 477	transport_remove_device(&starget->dev);
 478	device_del(&starget->dev);
 479	scsi_target_destroy(starget);
 480}
 481
 482/**
 483 * scsi_target_reap - check to see if target is in use and destroy if not
 484 * @starget: target to be checked
 485 *
 486 * This is used after removing a LUN or doing a last put of the target
 487 * it checks atomically that nothing is using the target and removes
 488 * it if so.
 489 */
 490void scsi_target_reap(struct scsi_target *starget)
 491{
 492	struct Scsi_Host *shost = dev_to_shost(starget->dev.parent);
 493	unsigned long flags;
 494	enum scsi_target_state state;
 495	int empty = 0;
 496
 497	spin_lock_irqsave(shost->host_lock, flags);
 498	state = starget->state;
 499	if (--starget->reap_ref == 0 && list_empty(&starget->devices)) {
 500		empty = 1;
 501		starget->state = STARGET_DEL;
 502	}
 503	spin_unlock_irqrestore(shost->host_lock, flags);
 504
 505	if (!empty)
 506		return;
 507
 508	BUG_ON(state == STARGET_DEL);
 509	if (state == STARGET_CREATED)
 510		scsi_target_destroy(starget);
 511	else
 512		execute_in_process_context(scsi_target_reap_usercontext,
 513					   &starget->ew);
 514}
 515
 516/**
 517 * sanitize_inquiry_string - remove non-graphical chars from an INQUIRY result string
 
 518 * @s: INQUIRY result string to sanitize
 519 * @len: length of the string
 520 *
 521 * Description:
 522 *	The SCSI spec says that INQUIRY vendor, product, and revision
 523 *	strings must consist entirely of graphic ASCII characters,
 524 *	padded on the right with spaces.  Since not all devices obey
 525 *	this rule, we will replace non-graphic or non-ASCII characters
 526 *	with spaces.  Exception: a NUL character is interpreted as a
 527 *	string terminator, so all the following characters are set to
 528 *	spaces.
 529 **/
 530static void sanitize_inquiry_string(unsigned char *s, int len)
 531{
 532	int terminated = 0;
 533
 534	for (; len > 0; (--len, ++s)) {
 535		if (*s == 0)
 536			terminated = 1;
 537		if (terminated || *s < 0x20 || *s > 0x7e)
 538			*s = ' ';
 539	}
 540}
 
 541
 542/**
 543 * scsi_probe_lun - probe a single LUN using a SCSI INQUIRY
 544 * @sdev:	scsi_device to probe
 545 * @inq_result:	area to store the INQUIRY result
 546 * @result_len: len of inq_result
 547 * @bflags:	store any bflags found here
 548 *
 549 * Description:
 550 *     Probe the lun associated with @req using a standard SCSI INQUIRY;
 551 *
 552 *     If the INQUIRY is successful, zero is returned and the
 553 *     INQUIRY data is in @inq_result; the scsi_level and INQUIRY length
 554 *     are copied to the scsi_device any flags value is stored in *@bflags.
 555 **/
 556static int scsi_probe_lun(struct scsi_device *sdev, unsigned char *inq_result,
 557			  int result_len, int *bflags)
 558{
 559	unsigned char scsi_cmd[MAX_COMMAND_SIZE];
 560	int first_inquiry_len, try_inquiry_len, next_inquiry_len;
 561	int response_len = 0;
 562	int pass, count, result;
 563	struct scsi_sense_hdr sshdr;
 564
 565	*bflags = 0;
 566
 567	/* Perform up to 3 passes.  The first pass uses a conservative
 568	 * transfer length of 36 unless sdev->inquiry_len specifies a
 569	 * different value. */
 570	first_inquiry_len = sdev->inquiry_len ? sdev->inquiry_len : 36;
 571	try_inquiry_len = first_inquiry_len;
 572	pass = 1;
 573
 574 next_pass:
 575	SCSI_LOG_SCAN_BUS(3, sdev_printk(KERN_INFO, sdev,
 576				"scsi scan: INQUIRY pass %d length %d\n",
 577				pass, try_inquiry_len));
 578
 579	/* Each pass gets up to three chances to ignore Unit Attention */
 580	for (count = 0; count < 3; ++count) {
 581		int resid;
 582
 583		memset(scsi_cmd, 0, 6);
 584		scsi_cmd[0] = INQUIRY;
 585		scsi_cmd[4] = (unsigned char) try_inquiry_len;
 586
 587		memset(inq_result, 0, try_inquiry_len);
 588
 589		result = scsi_execute_req(sdev,  scsi_cmd, DMA_FROM_DEVICE,
 590					  inq_result, try_inquiry_len, &sshdr,
 591					  HZ / 2 + HZ * scsi_inq_timeout, 3,
 592					  &resid);
 593
 594		SCSI_LOG_SCAN_BUS(3, printk(KERN_INFO "scsi scan: INQUIRY %s "
 595				"with code 0x%x\n",
 596				result ? "failed" : "successful", result));
 597
 598		if (result) {
 599			/*
 600			 * not-ready to ready transition [asc/ascq=0x28/0x0]
 601			 * or power-on, reset [asc/ascq=0x29/0x0], continue.
 602			 * INQUIRY should not yield UNIT_ATTENTION
 603			 * but many buggy devices do so anyway. 
 604			 */
 605			if ((driver_byte(result) & DRIVER_SENSE) &&
 606			    scsi_sense_valid(&sshdr)) {
 607				if ((sshdr.sense_key == UNIT_ATTENTION) &&
 608				    ((sshdr.asc == 0x28) ||
 609				     (sshdr.asc == 0x29)) &&
 610				    (sshdr.ascq == 0))
 611					continue;
 612			}
 613		} else {
 614			/*
 615			 * if nothing was transferred, we try
 616			 * again. It's a workaround for some USB
 617			 * devices.
 618			 */
 619			if (resid == try_inquiry_len)
 620				continue;
 621		}
 622		break;
 623	}
 624
 625	if (result == 0) {
 626		sanitize_inquiry_string(&inq_result[8], 8);
 627		sanitize_inquiry_string(&inq_result[16], 16);
 628		sanitize_inquiry_string(&inq_result[32], 4);
 629
 630		response_len = inq_result[4] + 5;
 631		if (response_len > 255)
 632			response_len = first_inquiry_len;	/* sanity */
 633
 634		/*
 635		 * Get any flags for this device.
 636		 *
 637		 * XXX add a bflags to scsi_device, and replace the
 638		 * corresponding bit fields in scsi_device, so bflags
 639		 * need not be passed as an argument.
 640		 */
 641		*bflags = scsi_get_device_flags(sdev, &inq_result[8],
 642				&inq_result[16]);
 643
 644		/* When the first pass succeeds we gain information about
 645		 * what larger transfer lengths might work. */
 646		if (pass == 1) {
 647			if (BLIST_INQUIRY_36 & *bflags)
 648				next_inquiry_len = 36;
 649			else if (BLIST_INQUIRY_58 & *bflags)
 650				next_inquiry_len = 58;
 651			else if (sdev->inquiry_len)
 652				next_inquiry_len = sdev->inquiry_len;
 653			else
 654				next_inquiry_len = response_len;
 655
 656			/* If more data is available perform the second pass */
 657			if (next_inquiry_len > try_inquiry_len) {
 658				try_inquiry_len = next_inquiry_len;
 659				pass = 2;
 660				goto next_pass;
 661			}
 662		}
 663
 664	} else if (pass == 2) {
 665		printk(KERN_INFO "scsi scan: %d byte inquiry failed.  "
 666				"Consider BLIST_INQUIRY_36 for this device\n",
 667				try_inquiry_len);
 
 668
 669		/* If this pass failed, the third pass goes back and transfers
 670		 * the same amount as we successfully got in the first pass. */
 671		try_inquiry_len = first_inquiry_len;
 672		pass = 3;
 673		goto next_pass;
 674	}
 675
 676	/* If the last transfer attempt got an error, assume the
 677	 * peripheral doesn't exist or is dead. */
 678	if (result)
 679		return -EIO;
 680
 681	/* Don't report any more data than the device says is valid */
 682	sdev->inquiry_len = min(try_inquiry_len, response_len);
 683
 684	/*
 685	 * XXX Abort if the response length is less than 36? If less than
 686	 * 32, the lookup of the device flags (above) could be invalid,
 687	 * and it would be possible to take an incorrect action - we do
 688	 * not want to hang because of a short INQUIRY. On the flip side,
 689	 * if the device is spun down or becoming ready (and so it gives a
 690	 * short INQUIRY), an abort here prevents any further use of the
 691	 * device, including spin up.
 692	 *
 693	 * On the whole, the best approach seems to be to assume the first
 694	 * 36 bytes are valid no matter what the device says.  That's
 695	 * better than copying < 36 bytes to the inquiry-result buffer
 696	 * and displaying garbage for the Vendor, Product, or Revision
 697	 * strings.
 698	 */
 699	if (sdev->inquiry_len < 36) {
 700		printk(KERN_INFO "scsi scan: INQUIRY result too short (%d),"
 701				" using 36\n", sdev->inquiry_len);
 
 
 
 
 702		sdev->inquiry_len = 36;
 703	}
 704
 705	/*
 706	 * Related to the above issue:
 707	 *
 708	 * XXX Devices (disk or all?) should be sent a TEST UNIT READY,
 709	 * and if not ready, sent a START_STOP to start (maybe spin up) and
 710	 * then send the INQUIRY again, since the INQUIRY can change after
 711	 * a device is initialized.
 712	 *
 713	 * Ideally, start a device if explicitly asked to do so.  This
 714	 * assumes that a device is spun up on power on, spun down on
 715	 * request, and then spun up on request.
 716	 */
 717
 718	/*
 719	 * The scanning code needs to know the scsi_level, even if no
 720	 * device is attached at LUN 0 (SCSI_SCAN_TARGET_PRESENT) so
 721	 * non-zero LUNs can be scanned.
 722	 */
 723	sdev->scsi_level = inq_result[2] & 0x07;
 724	if (sdev->scsi_level >= 2 ||
 725	    (sdev->scsi_level == 1 && (inq_result[3] & 0x0f) == 1))
 726		sdev->scsi_level++;
 727	sdev->sdev_target->scsi_level = sdev->scsi_level;
 728
 
 
 
 
 
 
 
 
 
 
 729	return 0;
 730}
 731
 732/**
 733 * scsi_add_lun - allocate and fully initialze a scsi_device
 734 * @sdev:	holds information to be stored in the new scsi_device
 735 * @inq_result:	holds the result of a previous INQUIRY to the LUN
 736 * @bflags:	black/white list flag
 737 * @async:	1 if this device is being scanned asynchronously
 738 *
 739 * Description:
 740 *     Initialize the scsi_device @sdev.  Optionally set fields based
 741 *     on values in *@bflags.
 742 *
 743 * Return:
 744 *     SCSI_SCAN_NO_RESPONSE: could not allocate or setup a scsi_device
 745 *     SCSI_SCAN_LUN_PRESENT: a new scsi_device was allocated and initialized
 746 **/
 747static int scsi_add_lun(struct scsi_device *sdev, unsigned char *inq_result,
 748		int *bflags, int async)
 749{
 750	int ret;
 751
 752	/*
 753	 * XXX do not save the inquiry, since it can change underneath us,
 754	 * save just vendor/model/rev.
 755	 *
 756	 * Rather than save it and have an ioctl that retrieves the saved
 757	 * value, have an ioctl that executes the same INQUIRY code used
 758	 * in scsi_probe_lun, let user level programs doing INQUIRY
 759	 * scanning run at their own risk, or supply a user level program
 760	 * that can correctly scan.
 761	 */
 762
 763	/*
 764	 * Copy at least 36 bytes of INQUIRY data, so that we don't
 765	 * dereference unallocated memory when accessing the Vendor,
 766	 * Product, and Revision strings.  Badly behaved devices may set
 767	 * the INQUIRY Additional Length byte to a small value, indicating
 768	 * these strings are invalid, but often they contain plausible data
 769	 * nonetheless.  It doesn't matter if the device sent < 36 bytes
 770	 * total, since scsi_probe_lun() initializes inq_result with 0s.
 771	 */
 772	sdev->inquiry = kmemdup(inq_result,
 773				max_t(size_t, sdev->inquiry_len, 36),
 774				GFP_ATOMIC);
 775	if (sdev->inquiry == NULL)
 776		return SCSI_SCAN_NO_RESPONSE;
 777
 778	sdev->vendor = (char *) (sdev->inquiry + 8);
 779	sdev->model = (char *) (sdev->inquiry + 16);
 780	sdev->rev = (char *) (sdev->inquiry + 32);
 781
 
 
 
 
 
 
 
 
 
 
 782	if (*bflags & BLIST_ISROM) {
 783		sdev->type = TYPE_ROM;
 784		sdev->removable = 1;
 785	} else {
 786		sdev->type = (inq_result[0] & 0x1f);
 787		sdev->removable = (inq_result[1] & 0x80) >> 7;
 788	}
 789
 790	switch (sdev->type) {
 791	case TYPE_RBC:
 792	case TYPE_TAPE:
 793	case TYPE_DISK:
 794	case TYPE_PRINTER:
 795	case TYPE_MOD:
 796	case TYPE_PROCESSOR:
 797	case TYPE_SCANNER:
 798	case TYPE_MEDIUM_CHANGER:
 799	case TYPE_ENCLOSURE:
 800	case TYPE_COMM:
 801	case TYPE_RAID:
 802	case TYPE_OSD:
 803		sdev->writeable = 1;
 804		break;
 805	case TYPE_ROM:
 806	case TYPE_WORM:
 807		sdev->writeable = 0;
 808		break;
 809	default:
 810		printk(KERN_INFO "scsi: unknown device type %d\n", sdev->type);
 811	}
 812
 813	if (sdev->type == TYPE_RBC || sdev->type == TYPE_ROM) {
 814		/* RBC and MMC devices can return SCSI-3 compliance and yet
 815		 * still not support REPORT LUNS, so make them act as
 816		 * BLIST_NOREPORTLUN unless BLIST_REPORTLUN2 is
 817		 * specifically set */
 818		if ((*bflags & BLIST_REPORTLUN2) == 0)
 819			*bflags |= BLIST_NOREPORTLUN;
 820	}
 821
 822	/*
 823	 * For a peripheral qualifier (PQ) value of 1 (001b), the SCSI
 824	 * spec says: The device server is capable of supporting the
 825	 * specified peripheral device type on this logical unit. However,
 826	 * the physical device is not currently connected to this logical
 827	 * unit.
 828	 *
 829	 * The above is vague, as it implies that we could treat 001 and
 830	 * 011 the same. Stay compatible with previous code, and create a
 831	 * scsi_device for a PQ of 1
 832	 *
 833	 * Don't set the device offline here; rather let the upper
 834	 * level drivers eval the PQ to decide whether they should
 835	 * attach. So remove ((inq_result[0] >> 5) & 7) == 1 check.
 836	 */ 
 837
 838	sdev->inq_periph_qual = (inq_result[0] >> 5) & 7;
 839	sdev->lockable = sdev->removable;
 840	sdev->soft_reset = (inq_result[7] & 1) && ((inq_result[3] & 7) == 2);
 841
 842	if (sdev->scsi_level >= SCSI_3 ||
 843			(sdev->inquiry_len > 56 && inq_result[56] & 0x04))
 844		sdev->ppr = 1;
 845	if (inq_result[7] & 0x60)
 846		sdev->wdtr = 1;
 847	if (inq_result[7] & 0x10)
 848		sdev->sdtr = 1;
 849
 850	sdev_printk(KERN_NOTICE, sdev, "%s %.8s %.16s %.4s PQ: %d "
 851			"ANSI: %d%s\n", scsi_device_type(sdev->type),
 852			sdev->vendor, sdev->model, sdev->rev,
 853			sdev->inq_periph_qual, inq_result[2] & 0x07,
 854			(inq_result[3] & 0x0f) == 1 ? " CCS" : "");
 855
 856	if ((sdev->scsi_level >= SCSI_2) && (inq_result[7] & 2) &&
 857	    !(*bflags & BLIST_NOTQ))
 858		sdev->tagged_supported = 1;
 
 
 859
 860	/*
 861	 * Some devices (Texel CD ROM drives) have handshaking problems
 862	 * when used with the Seagate controllers. borken is initialized
 863	 * to 1, and then set it to 0 here.
 864	 */
 865	if ((*bflags & BLIST_BORKEN) == 0)
 866		sdev->borken = 0;
 867
 868	if (*bflags & BLIST_NO_ULD_ATTACH)
 869		sdev->no_uld_attach = 1;
 870
 871	/*
 872	 * Apparently some really broken devices (contrary to the SCSI
 873	 * standards) need to be selected without asserting ATN
 874	 */
 875	if (*bflags & BLIST_SELECT_NO_ATN)
 876		sdev->select_no_atn = 1;
 877
 878	/*
 879	 * Maximum 512 sector transfer length
 880	 * broken RA4x00 Compaq Disk Array
 881	 */
 882	if (*bflags & BLIST_MAX_512)
 883		blk_queue_max_hw_sectors(sdev->request_queue, 512);
 
 
 
 
 
 
 884
 885	/*
 886	 * Some devices may not want to have a start command automatically
 887	 * issued when a device is added.
 888	 */
 889	if (*bflags & BLIST_NOSTARTONADD)
 890		sdev->no_start_on_add = 1;
 891
 892	if (*bflags & BLIST_SINGLELUN)
 893		scsi_target(sdev)->single_lun = 1;
 894
 895	sdev->use_10_for_rw = 1;
 896
 897	if (*bflags & BLIST_MS_SKIP_PAGE_08)
 898		sdev->skip_ms_page_8 = 1;
 899
 900	if (*bflags & BLIST_MS_SKIP_PAGE_3F)
 901		sdev->skip_ms_page_3f = 1;
 902
 903	if (*bflags & BLIST_USE_10_BYTE_MS)
 904		sdev->use_10_for_ms = 1;
 905
 906	/* set the device running here so that slave configure
 907	 * may do I/O */
 
 908	ret = scsi_device_set_state(sdev, SDEV_RUNNING);
 909	if (ret) {
 910		ret = scsi_device_set_state(sdev, SDEV_BLOCK);
 
 911
 912		if (ret) {
 913			sdev_printk(KERN_ERR, sdev,
 914				    "in wrong state %s to complete scan\n",
 915				    scsi_device_state_name(sdev->sdev_state));
 916			return SCSI_SCAN_NO_RESPONSE;
 917		}
 918	}
 919
 920	if (*bflags & BLIST_MS_192_BYTES_FOR_3F)
 921		sdev->use_192_bytes_for_3f = 1;
 922
 923	if (*bflags & BLIST_NOT_LOCKABLE)
 924		sdev->lockable = 0;
 925
 926	if (*bflags & BLIST_RETRY_HWERROR)
 927		sdev->retry_hwerror = 1;
 928
 
 
 
 
 
 
 
 
 
 
 
 
 
 929	transport_configure_device(&sdev->sdev_gendev);
 930
 931	if (sdev->host->hostt->slave_configure) {
 932		ret = sdev->host->hostt->slave_configure(sdev);
 933		if (ret) {
 934			/*
 935			 * if LLDD reports slave not present, don't clutter
 936			 * console with alloc failure messages
 937			 */
 938			if (ret != -ENXIO) {
 939				sdev_printk(KERN_ERR, sdev,
 940					"failed to configure device\n");
 941			}
 942			return SCSI_SCAN_NO_RESPONSE;
 943		}
 944	}
 945
 
 
 
 946	sdev->max_queue_depth = sdev->queue_depth;
 
 947
 948	/*
 949	 * Ok, the device is now all set up, we can
 950	 * register it and tell the rest of the kernel
 951	 * about it.
 952	 */
 953	if (!async && scsi_sysfs_add_sdev(sdev) != 0)
 954		return SCSI_SCAN_NO_RESPONSE;
 955
 956	return SCSI_SCAN_LUN_PRESENT;
 957}
 958
 959#ifdef CONFIG_SCSI_LOGGING
 960/** 
 961 * scsi_inq_str - print INQUIRY data from min to max index, strip trailing whitespace
 962 * @buf:   Output buffer with at least end-first+1 bytes of space
 963 * @inq:   Inquiry buffer (input)
 964 * @first: Offset of string into inq
 965 * @end:   Index after last character in inq
 966 */
 967static unsigned char *scsi_inq_str(unsigned char *buf, unsigned char *inq,
 968				   unsigned first, unsigned end)
 969{
 970	unsigned term = 0, idx;
 971
 972	for (idx = 0; idx + first < end && idx + first < inq[4] + 5; idx++) {
 973		if (inq[idx+first] > ' ') {
 974			buf[idx] = inq[idx+first];
 975			term = idx+1;
 976		} else {
 977			buf[idx] = ' ';
 978		}
 979	}
 980	buf[term] = 0;
 981	return buf;
 982}
 983#endif
 984
 985/**
 986 * scsi_probe_and_add_lun - probe a LUN, if a LUN is found add it
 987 * @starget:	pointer to target device structure
 988 * @lun:	LUN of target device
 989 * @bflagsp:	store bflags here if not NULL
 990 * @sdevp:	probe the LUN corresponding to this scsi_device
 991 * @rescan:     if nonzero skip some code only needed on first scan
 
 992 * @hostdata:	passed to scsi_alloc_sdev()
 993 *
 994 * Description:
 995 *     Call scsi_probe_lun, if a LUN with an attached device is found,
 996 *     allocate and set it up by calling scsi_add_lun.
 997 *
 998 * Return:
 999 *     SCSI_SCAN_NO_RESPONSE: could not allocate or setup a scsi_device
1000 *     SCSI_SCAN_TARGET_PRESENT: target responded, but no device is
 
1001 *         attached at the LUN
1002 *     SCSI_SCAN_LUN_PRESENT: a new scsi_device was allocated and initialized
1003 **/
1004static int scsi_probe_and_add_lun(struct scsi_target *starget,
1005				  uint lun, int *bflagsp,
1006				  struct scsi_device **sdevp, int rescan,
 
1007				  void *hostdata)
1008{
1009	struct scsi_device *sdev;
1010	unsigned char *result;
1011	int bflags, res = SCSI_SCAN_NO_RESPONSE, result_len = 256;
 
1012	struct Scsi_Host *shost = dev_to_shost(starget->dev.parent);
1013
1014	/*
1015	 * The rescan flag is used as an optimization, the first scan of a
1016	 * host adapter calls into here with rescan == 0.
1017	 */
1018	sdev = scsi_device_lookup_by_target(starget, lun);
1019	if (sdev) {
1020		if (rescan || !scsi_device_created(sdev)) {
1021			SCSI_LOG_SCAN_BUS(3, printk(KERN_INFO
1022				"scsi scan: device exists on %s\n",
1023				dev_name(&sdev->sdev_gendev)));
1024			if (sdevp)
1025				*sdevp = sdev;
1026			else
1027				scsi_device_put(sdev);
1028
1029			if (bflagsp)
1030				*bflagsp = scsi_get_device_flags(sdev,
1031								 sdev->vendor,
1032								 sdev->model);
1033			return SCSI_SCAN_LUN_PRESENT;
1034		}
1035		scsi_device_put(sdev);
1036	} else
1037		sdev = scsi_alloc_sdev(starget, lun, hostdata);
1038	if (!sdev)
1039		goto out;
1040
1041	result = kmalloc(result_len, GFP_ATOMIC |
1042			((shost->unchecked_isa_dma) ? __GFP_DMA : 0));
1043	if (!result)
1044		goto out_free_sdev;
1045
1046	if (scsi_probe_lun(sdev, result, result_len, &bflags))
1047		goto out_free_result;
1048
1049	if (bflagsp)
1050		*bflagsp = bflags;
1051	/*
1052	 * result contains valid SCSI INQUIRY data.
1053	 */
1054	if (((result[0] >> 5) == 3) && !(bflags & BLIST_ATTACH_PQ3)) {
1055		/*
1056		 * For a Peripheral qualifier 3 (011b), the SCSI
1057		 * spec says: The device server is not capable of
1058		 * supporting a physical device on this logical
1059		 * unit.
1060		 *
1061		 * For disks, this implies that there is no
1062		 * logical disk configured at sdev->lun, but there
1063		 * is a target id responding.
1064		 */
1065		SCSI_LOG_SCAN_BUS(2, sdev_printk(KERN_INFO, sdev, "scsi scan:"
1066				   " peripheral qualifier of 3, device not"
1067				   " added\n"))
1068		if (lun == 0) {
1069			SCSI_LOG_SCAN_BUS(1, {
1070				unsigned char vend[9];
1071				unsigned char mod[17];
1072
1073				sdev_printk(KERN_INFO, sdev,
1074					"scsi scan: consider passing scsi_mod."
1075					"dev_flags=%s:%s:0x240 or 0x1000240\n",
1076					scsi_inq_str(vend, result, 8, 16),
1077					scsi_inq_str(mod, result, 16, 32));
1078			});
1079
1080		}
1081
1082		res = SCSI_SCAN_TARGET_PRESENT;
1083		goto out_free_result;
1084	}
1085
1086	/*
1087	 * Some targets may set slight variations of PQ and PDT to signal
1088	 * that no LUN is present, so don't add sdev in these cases.
1089	 * Two specific examples are:
1090	 * 1) NetApp targets: return PQ=1, PDT=0x1f
1091	 * 2) USB UFI: returns PDT=0x1f, with the PQ bits being "reserved"
1092	 *    in the UFI 1.0 spec (we cannot rely on reserved bits).
1093	 *
1094	 * References:
1095	 * 1) SCSI SPC-3, pp. 145-146
1096	 * PQ=1: "A peripheral device having the specified peripheral
1097	 * device type is not connected to this logical unit. However, the
1098	 * device server is capable of supporting the specified peripheral
1099	 * device type on this logical unit."
1100	 * PDT=0x1f: "Unknown or no device type"
1101	 * 2) USB UFI 1.0, p. 20
1102	 * PDT=00h Direct-access device (floppy)
1103	 * PDT=1Fh none (no FDD connected to the requested logical unit)
1104	 */
1105	if (((result[0] >> 5) == 1 || starget->pdt_1f_for_no_lun) &&
1106	    (result[0] & 0x1f) == 0x1f &&
1107	    !scsi_is_wlun(lun)) {
1108		SCSI_LOG_SCAN_BUS(3, printk(KERN_INFO
1109					"scsi scan: peripheral device type"
1110					" of 31, no device added\n"));
1111		res = SCSI_SCAN_TARGET_PRESENT;
1112		goto out_free_result;
1113	}
1114
1115	res = scsi_add_lun(sdev, result, &bflags, shost->async_scan);
1116	if (res == SCSI_SCAN_LUN_PRESENT) {
1117		if (bflags & BLIST_KEY) {
1118			sdev->lockable = 0;
1119			scsi_unlock_floptical(sdev, result);
1120		}
1121	}
1122
1123 out_free_result:
1124	kfree(result);
1125 out_free_sdev:
1126	if (res == SCSI_SCAN_LUN_PRESENT) {
1127		if (sdevp) {
1128			if (scsi_device_get(sdev) == 0) {
1129				*sdevp = sdev;
1130			} else {
1131				__scsi_remove_device(sdev);
1132				res = SCSI_SCAN_NO_RESPONSE;
1133			}
1134		}
1135	} else
1136		__scsi_remove_device(sdev);
1137 out:
1138	return res;
1139}
1140
1141/**
1142 * scsi_sequential_lun_scan - sequentially scan a SCSI target
1143 * @starget:	pointer to target structure to scan
1144 * @bflags:	black/white list flag for LUN 0
1145 * @scsi_level: Which version of the standard does this device adhere to
1146 * @rescan:     passed to scsi_probe_add_lun()
1147 *
1148 * Description:
1149 *     Generally, scan from LUN 1 (LUN 0 is assumed to already have been
1150 *     scanned) to some maximum lun until a LUN is found with no device
1151 *     attached. Use the bflags to figure out any oddities.
1152 *
1153 *     Modifies sdevscan->lun.
1154 **/
1155static void scsi_sequential_lun_scan(struct scsi_target *starget,
1156				     int bflags, int scsi_level, int rescan)
 
1157{
1158	unsigned int sparse_lun, lun, max_dev_lun;
 
1159	struct Scsi_Host *shost = dev_to_shost(starget->dev.parent);
1160
1161	SCSI_LOG_SCAN_BUS(3, printk(KERN_INFO "scsi scan: Sequential scan of"
1162				    "%s\n", dev_name(&starget->dev)));
1163
1164	max_dev_lun = min(max_scsi_luns, shost->max_lun);
1165	/*
1166	 * If this device is known to support sparse multiple units,
1167	 * override the other settings, and scan all of them. Normally,
1168	 * SCSI-3 devices should be scanned via the REPORT LUNS.
1169	 */
1170	if (bflags & BLIST_SPARSELUN) {
1171		max_dev_lun = shost->max_lun;
1172		sparse_lun = 1;
1173	} else
1174		sparse_lun = 0;
1175
1176	/*
1177	 * If less than SCSI_1_CSS, and no special lun scaning, stop
1178	 * scanning; this matches 2.4 behaviour, but could just be a bug
1179	 * (to continue scanning a SCSI_1_CSS device).
1180	 *
1181	 * This test is broken.  We might not have any device on lun0 for
1182	 * a sparselun device, and if that's the case then how would we
1183	 * know the real scsi_level, eh?  It might make sense to just not
1184	 * scan any SCSI_1 device for non-0 luns, but that check would best
1185	 * go into scsi_alloc_sdev() and just have it return null when asked
1186	 * to alloc an sdev for lun > 0 on an already found SCSI_1 device.
1187	 *
1188	if ((sdevscan->scsi_level < SCSI_1_CCS) &&
1189	    ((bflags & (BLIST_FORCELUN | BLIST_SPARSELUN | BLIST_MAX5LUN))
1190	     == 0))
1191		return;
1192	 */
1193	/*
1194	 * If this device is known to support multiple units, override
1195	 * the other settings, and scan all of them.
1196	 */
1197	if (bflags & BLIST_FORCELUN)
1198		max_dev_lun = shost->max_lun;
1199	/*
1200	 * REGAL CDC-4X: avoid hang after LUN 4
1201	 */
1202	if (bflags & BLIST_MAX5LUN)
1203		max_dev_lun = min(5U, max_dev_lun);
1204	/*
1205	 * Do not scan SCSI-2 or lower device past LUN 7, unless
1206	 * BLIST_LARGELUN.
1207	 */
1208	if (scsi_level < SCSI_3 && !(bflags & BLIST_LARGELUN))
1209		max_dev_lun = min(8U, max_dev_lun);
 
 
1210
1211	/*
1212	 * We have already scanned LUN 0, so start at LUN 1. Keep scanning
1213	 * until we reach the max, or no LUN is found and we are not
1214	 * sparse_lun.
1215	 */
1216	for (lun = 1; lun < max_dev_lun; ++lun)
1217		if ((scsi_probe_and_add_lun(starget, lun, NULL, NULL, rescan,
1218					    NULL) != SCSI_SCAN_LUN_PRESENT) &&
1219		    !sparse_lun)
1220			return;
1221}
1222
1223/**
1224 * scsilun_to_int - convert a scsi_lun to an int
1225 * @scsilun:	struct scsi_lun to be converted.
1226 *
1227 * Description:
1228 *     Convert @scsilun from a struct scsi_lun to a four byte host byte-ordered
1229 *     integer, and return the result. The caller must check for
1230 *     truncation before using this function.
1231 *
1232 * Notes:
1233 *     The struct scsi_lun is assumed to be four levels, with each level
1234 *     effectively containing a SCSI byte-ordered (big endian) short; the
1235 *     addressing bits of each level are ignored (the highest two bits).
1236 *     For a description of the LUN format, post SCSI-3 see the SCSI
1237 *     Architecture Model, for SCSI-3 see the SCSI Controller Commands.
1238 *
1239 *     Given a struct scsi_lun of: 0a 04 0b 03 00 00 00 00, this function returns
1240 *     the integer: 0x0b030a04
1241 **/
1242int scsilun_to_int(struct scsi_lun *scsilun)
1243{
1244	int i;
1245	unsigned int lun;
1246
1247	lun = 0;
1248	for (i = 0; i < sizeof(lun); i += 2)
1249		lun = lun | (((scsilun->scsi_lun[i] << 8) |
1250			      scsilun->scsi_lun[i + 1]) << (i * 8));
1251	return lun;
1252}
1253EXPORT_SYMBOL(scsilun_to_int);
1254
1255/**
1256 * int_to_scsilun - reverts an int into a scsi_lun
1257 * @lun:        integer to be reverted
1258 * @scsilun:	struct scsi_lun to be set.
1259 *
1260 * Description:
1261 *     Reverts the functionality of the scsilun_to_int, which packed
1262 *     an 8-byte lun value into an int. This routine unpacks the int
1263 *     back into the lun value.
1264 *     Note: the scsilun_to_int() routine does not truly handle all
1265 *     8bytes of the lun value. This functions restores only as much
1266 *     as was set by the routine.
1267 *
1268 * Notes:
1269 *     Given an integer : 0x0b030a04,  this function returns a
1270 *     scsi_lun of : struct scsi_lun of: 0a 04 0b 03 00 00 00 00
1271 *
1272 **/
1273void int_to_scsilun(unsigned int lun, struct scsi_lun *scsilun)
1274{
1275	int i;
1276
1277	memset(scsilun->scsi_lun, 0, sizeof(scsilun->scsi_lun));
1278
1279	for (i = 0; i < sizeof(lun); i += 2) {
1280		scsilun->scsi_lun[i] = (lun >> 8) & 0xFF;
1281		scsilun->scsi_lun[i+1] = lun & 0xFF;
1282		lun = lun >> 16;
1283	}
1284}
1285EXPORT_SYMBOL(int_to_scsilun);
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 *
1302 * Return:
1303 *     0: scan completed (or no memory, so further scanning is futile)
1304 *     1: could not scan with REPORT LUN
1305 **/
1306static int scsi_report_lun_scan(struct scsi_target *starget, int bflags,
1307				int rescan)
1308{
1309	char devname[64];
1310	unsigned char scsi_cmd[MAX_COMMAND_SIZE];
1311	unsigned int length;
1312	unsigned int lun;
1313	unsigned int num_luns;
1314	unsigned int retries;
1315	int result;
1316	struct scsi_lun *lunp, *lun_data;
1317	u8 *data;
1318	struct scsi_sense_hdr sshdr;
1319	struct scsi_device *sdev;
1320	struct Scsi_Host *shost = dev_to_shost(&starget->dev);
1321	int ret = 0;
1322
1323	/*
1324	 * Only support SCSI-3 and up devices if BLIST_NOREPORTLUN is not set.
1325	 * Also allow SCSI-2 if BLIST_REPORTLUN2 is set and host adapter does
1326	 * support more than 8 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
1339	if (!(sdev = scsi_device_lookup_by_target(starget, 0))) {
1340		sdev = scsi_alloc_sdev(starget, 0, NULL);
1341		if (!sdev)
1342			return 0;
1343		if (scsi_device_get(sdev)) {
1344			__scsi_remove_device(sdev);
1345			return 0;
1346		}
1347	}
1348
1349	sprintf(devname, "host %d channel %d id %d",
1350		shost->host_no, sdev->channel, sdev->id);
1351
1352	/*
1353	 * Allocate enough to hold the header (the same size as one scsi_lun)
1354	 * plus the max number of luns we are requesting.
1355	 *
1356	 * Reallocating and trying again (with the exact amount we need)
1357	 * would be nice, but then we need to somehow limit the size
1358	 * allocated based on the available memory and the limits of
1359	 * kmalloc - we don't want a kmalloc() failure of a huge value to
1360	 * prevent us from finding any LUNs on this target.
1361	 */
1362	length = (max_scsi_report_luns + 1) * sizeof(struct scsi_lun);
1363	lun_data = kmalloc(length, GFP_ATOMIC |
 
1364			   (sdev->host->unchecked_isa_dma ? __GFP_DMA : 0));
1365	if (!lun_data) {
1366		printk(ALLOC_FAILURE_MSG, __func__);
1367		goto out;
1368	}
1369
1370	scsi_cmd[0] = REPORT_LUNS;
1371
1372	/*
1373	 * bytes 1 - 5: reserved, set to zero.
1374	 */
1375	memset(&scsi_cmd[1], 0, 5);
1376
1377	/*
1378	 * bytes 6 - 9: length of the command.
1379	 */
1380	scsi_cmd[6] = (unsigned char) (length >> 24) & 0xff;
1381	scsi_cmd[7] = (unsigned char) (length >> 16) & 0xff;
1382	scsi_cmd[8] = (unsigned char) (length >> 8) & 0xff;
1383	scsi_cmd[9] = (unsigned char) length & 0xff;
1384
1385	scsi_cmd[10] = 0;	/* reserved */
1386	scsi_cmd[11] = 0;	/* control */
1387
1388	/*
1389	 * We can get a UNIT ATTENTION, for example a power on/reset, so
1390	 * retry a few times (like sd.c does for TEST UNIT READY).
1391	 * Experience shows some combinations of adapter/devices get at
1392	 * least two power on/resets.
1393	 *
1394	 * Illegal requests (for devices that do not support REPORT LUNS)
1395	 * should come through as a check condition, and will not generate
1396	 * a retry.
1397	 */
1398	for (retries = 0; retries < 3; retries++) {
1399		SCSI_LOG_SCAN_BUS(3, printk (KERN_INFO "scsi scan: Sending"
1400				" REPORT LUNS to %s (try %d)\n", devname,
1401				retries));
1402
1403		result = scsi_execute_req(sdev, scsi_cmd, DMA_FROM_DEVICE,
1404					  lun_data, length, &sshdr,
1405					  SCSI_TIMEOUT + 4 * HZ, 3, NULL);
1406
1407		SCSI_LOG_SCAN_BUS(3, printk (KERN_INFO "scsi scan: REPORT LUNS"
1408				" %s (try %d) result 0x%x\n", result
1409				?  "failed" : "successful", retries, result));
 
 
1410		if (result == 0)
1411			break;
1412		else if (scsi_sense_valid(&sshdr)) {
1413			if (sshdr.sense_key != UNIT_ATTENTION)
1414				break;
1415		}
1416	}
1417
1418	if (result) {
1419		/*
1420		 * The device probably does not support a REPORT LUN command
1421		 */
1422		ret = 1;
1423		goto out_err;
1424	}
1425
1426	/*
1427	 * Get the length from the first four bytes of lun_data.
1428	 */
1429	data = (u8 *) lun_data->scsi_lun;
1430	length = ((data[0] << 24) | (data[1] << 16) |
1431		  (data[2] << 8) | (data[3] << 0));
 
 
 
 
 
1432
1433	num_luns = (length / sizeof(struct scsi_lun));
1434	if (num_luns > max_scsi_report_luns) {
1435		printk(KERN_WARNING "scsi: On %s only %d (max_scsi_report_luns)"
1436		       " of %d luns reported, try increasing"
1437		       " max_scsi_report_luns.\n", devname,
1438		       max_scsi_report_luns, num_luns);
1439		num_luns = max_scsi_report_luns;
1440	}
1441
1442	SCSI_LOG_SCAN_BUS(3, sdev_printk (KERN_INFO, sdev,
1443		"scsi scan: REPORT LUN scan\n"));
1444
1445	/*
1446	 * Scan the luns in lun_data. The entry at offset 0 is really
1447	 * the header, so start at 1 and go up to and including num_luns.
1448	 */
1449	for (lunp = &lun_data[1]; lunp <= &lun_data[num_luns]; lunp++) {
1450		lun = scsilun_to_int(lunp);
1451
1452		/*
1453		 * Check if the unused part of lunp is non-zero, and so
1454		 * does not fit in lun.
1455		 */
1456		if (memcmp(&lunp->scsi_lun[sizeof(lun)], "\0\0\0\0", 4)) {
1457			int i;
1458
1459			/*
1460			 * Output an error displaying the LUN in byte order,
1461			 * this differs from what linux would print for the
1462			 * integer LUN value.
1463			 */
1464			printk(KERN_WARNING "scsi: %s lun 0x", devname);
1465			data = (char *)lunp->scsi_lun;
1466			for (i = 0; i < sizeof(struct scsi_lun); i++)
1467				printk("%02x", data[i]);
1468			printk(" has a LUN larger than currently supported.\n");
1469		} else if (lun > sdev->host->max_lun) {
1470			printk(KERN_WARNING "scsi: %s lun%d has a LUN larger"
1471			       " than allowed by the host adapter\n",
1472			       devname, lun);
1473		} else {
1474			int res;
1475
1476			res = scsi_probe_and_add_lun(starget,
1477				lun, NULL, NULL, rescan, NULL);
1478			if (res == SCSI_SCAN_NO_RESPONSE) {
1479				/*
1480				 * Got some results, but now none, abort.
1481				 */
1482				sdev_printk(KERN_ERR, sdev,
1483					"Unexpected response"
1484				        " from lun %d while scanning, scan"
1485				        " aborted\n", lun);
1486				break;
1487			}
1488		}
1489	}
1490
1491 out_err:
1492	kfree(lun_data);
1493 out:
1494	scsi_device_put(sdev);
1495	if (scsi_device_created(sdev))
1496		/*
1497		 * the sdev we used didn't appear in the report luns scan
1498		 */
1499		__scsi_remove_device(sdev);
 
1500	return ret;
1501}
1502
1503struct scsi_device *__scsi_add_device(struct Scsi_Host *shost, uint channel,
1504				      uint id, uint lun, void *hostdata)
1505{
1506	struct scsi_device *sdev = ERR_PTR(-ENODEV);
1507	struct device *parent = &shost->shost_gendev;
1508	struct scsi_target *starget;
1509
1510	if (strncmp(scsi_scan_type, "none", 4) == 0)
1511		return ERR_PTR(-ENODEV);
1512
1513	starget = scsi_alloc_target(parent, channel, id);
1514	if (!starget)
1515		return ERR_PTR(-ENOMEM);
1516	scsi_autopm_get_target(starget);
1517
1518	mutex_lock(&shost->scan_mutex);
1519	if (!shost->async_scan)
1520		scsi_complete_async_scans();
1521
1522	if (scsi_host_scan_allowed(shost) && scsi_autopm_get_host(shost) == 0) {
1523		scsi_probe_and_add_lun(starget, lun, NULL, &sdev, 1, hostdata);
1524		scsi_autopm_put_host(shost);
1525	}
1526	mutex_unlock(&shost->scan_mutex);
1527	scsi_autopm_put_target(starget);
 
 
 
 
1528	scsi_target_reap(starget);
1529	put_device(&starget->dev);
1530
1531	return sdev;
1532}
1533EXPORT_SYMBOL(__scsi_add_device);
1534
1535int scsi_add_device(struct Scsi_Host *host, uint channel,
1536		    uint target, uint lun)
1537{
1538	struct scsi_device *sdev = 
1539		__scsi_add_device(host, channel, target, lun, NULL);
1540	if (IS_ERR(sdev))
1541		return PTR_ERR(sdev);
1542
1543	scsi_device_put(sdev);
1544	return 0;
1545}
1546EXPORT_SYMBOL(scsi_add_device);
1547
1548void scsi_rescan_device(struct device *dev)
1549{
1550	struct scsi_driver *drv;
1551	
1552	if (!dev->driver)
1553		return;
 
 
 
 
 
 
 
1554
1555	drv = to_scsi_driver(dev->driver);
1556	if (try_module_get(drv->owner)) {
1557		if (drv->rescan)
1558			drv->rescan(dev);
1559		module_put(drv->owner);
1560	}
 
1561}
1562EXPORT_SYMBOL(scsi_rescan_device);
1563
1564static void __scsi_scan_target(struct device *parent, unsigned int channel,
1565		unsigned int id, unsigned int lun, int rescan)
1566{
1567	struct Scsi_Host *shost = dev_to_shost(parent);
1568	int bflags = 0;
1569	int res;
1570	struct scsi_target *starget;
1571
1572	if (shost->this_id == id)
1573		/*
1574		 * Don't scan the host adapter
1575		 */
1576		return;
1577
1578	starget = scsi_alloc_target(parent, channel, id);
1579	if (!starget)
1580		return;
1581	scsi_autopm_get_target(starget);
1582
1583	if (lun != SCAN_WILD_CARD) {
1584		/*
1585		 * Scan for a specific host/chan/id/lun.
1586		 */
1587		scsi_probe_and_add_lun(starget, lun, NULL, NULL, rescan, NULL);
1588		goto out_reap;
1589	}
1590
1591	/*
1592	 * Scan LUN 0, if there is some response, scan further. Ideally, we
1593	 * would not configure LUN 0 until all LUNs are scanned.
1594	 */
1595	res = scsi_probe_and_add_lun(starget, 0, &bflags, NULL, rescan, NULL);
1596	if (res == SCSI_SCAN_LUN_PRESENT || res == SCSI_SCAN_TARGET_PRESENT) {
1597		if (scsi_report_lun_scan(starget, bflags, rescan) != 0)
1598			/*
1599			 * The REPORT LUN did not scan the target,
1600			 * do a sequential scan.
1601			 */
1602			scsi_sequential_lun_scan(starget, bflags,
1603						 starget->scsi_level, rescan);
1604	}
1605
1606 out_reap:
1607	scsi_autopm_put_target(starget);
1608	/* now determine if the target has any children at all
1609	 * and if not, nuke it */
 
 
1610	scsi_target_reap(starget);
1611
1612	put_device(&starget->dev);
1613}
1614
1615/**
1616 * scsi_scan_target - scan a target id, possibly including all LUNs on the target.
1617 * @parent:	host to scan
1618 * @channel:	channel to scan
1619 * @id:		target id to scan
1620 * @lun:	Specific LUN to scan or SCAN_WILD_CARD
1621 * @rescan:	passed to LUN scanning routines
 
 
 
1622 *
1623 * Description:
1624 *     Scan the target id on @parent, @channel, and @id. Scan at least LUN 0,
1625 *     and possibly all LUNs on the target id.
1626 *
1627 *     First try a REPORT LUN scan, if that does not scan the target, do a
1628 *     sequential scan of LUNs on the target id.
1629 **/
1630void scsi_scan_target(struct device *parent, unsigned int channel,
1631		      unsigned int id, unsigned int lun, int rescan)
1632{
1633	struct Scsi_Host *shost = dev_to_shost(parent);
1634
1635	if (strncmp(scsi_scan_type, "none", 4) == 0)
1636		return;
1637
 
 
 
 
1638	mutex_lock(&shost->scan_mutex);
1639	if (!shost->async_scan)
1640		scsi_complete_async_scans();
1641
1642	if (scsi_host_scan_allowed(shost) && scsi_autopm_get_host(shost) == 0) {
1643		__scsi_scan_target(parent, channel, id, lun, rescan);
1644		scsi_autopm_put_host(shost);
1645	}
1646	mutex_unlock(&shost->scan_mutex);
1647}
1648EXPORT_SYMBOL(scsi_scan_target);
1649
1650static void scsi_scan_channel(struct Scsi_Host *shost, unsigned int channel,
1651			      unsigned int id, unsigned int lun, int rescan)
 
1652{
1653	uint order_id;
1654
1655	if (id == SCAN_WILD_CARD)
1656		for (id = 0; id < shost->max_id; ++id) {
1657			/*
1658			 * XXX adapter drivers when possible (FCP, iSCSI)
1659			 * could modify max_id to match the current max,
1660			 * not the absolute max.
1661			 *
1662			 * XXX add a shost id iterator, so for example,
1663			 * the FC ID can be the same as a target id
1664			 * without a huge overhead of sparse id's.
1665			 */
1666			if (shost->reverse_ordering)
1667				/*
1668				 * Scan from high to low id.
1669				 */
1670				order_id = shost->max_id - id - 1;
1671			else
1672				order_id = id;
1673			__scsi_scan_target(&shost->shost_gendev, channel,
1674					order_id, lun, rescan);
1675		}
1676	else
1677		__scsi_scan_target(&shost->shost_gendev, channel,
1678				id, lun, rescan);
1679}
1680
1681int scsi_scan_host_selected(struct Scsi_Host *shost, unsigned int channel,
1682			    unsigned int id, unsigned int lun, int rescan)
 
1683{
1684	SCSI_LOG_SCAN_BUS(3, shost_printk (KERN_INFO, shost,
1685		"%s: <%u:%u:%u>\n",
1686		__func__, channel, id, lun));
1687
1688	if (((channel != SCAN_WILD_CARD) && (channel > shost->max_channel)) ||
1689	    ((id != SCAN_WILD_CARD) && (id >= shost->max_id)) ||
1690	    ((lun != SCAN_WILD_CARD) && (lun > shost->max_lun)))
1691		return -EINVAL;
1692
1693	mutex_lock(&shost->scan_mutex);
1694	if (!shost->async_scan)
1695		scsi_complete_async_scans();
1696
1697	if (scsi_host_scan_allowed(shost) && scsi_autopm_get_host(shost) == 0) {
1698		if (channel == SCAN_WILD_CARD)
1699			for (channel = 0; channel <= shost->max_channel;
1700			     channel++)
1701				scsi_scan_channel(shost, channel, id, lun,
1702						  rescan);
1703		else
1704			scsi_scan_channel(shost, channel, id, lun, rescan);
1705		scsi_autopm_put_host(shost);
1706	}
1707	mutex_unlock(&shost->scan_mutex);
1708
1709	return 0;
1710}
1711
1712static void scsi_sysfs_add_devices(struct Scsi_Host *shost)
1713{
1714	struct scsi_device *sdev;
1715	shost_for_each_device(sdev, shost) {
 
 
 
 
 
 
1716		if (!scsi_host_scan_allowed(shost) ||
1717		    scsi_sysfs_add_sdev(sdev) != 0)
1718			__scsi_remove_device(sdev);
1719	}
1720}
1721
1722/**
1723 * scsi_prep_async_scan - prepare for an async scan
1724 * @shost: the host which will be scanned
1725 * Returns: a cookie to be passed to scsi_finish_async_scan()
1726 *
1727 * Tells the midlayer this host is going to do an asynchronous scan.
1728 * It reserves the host's position in the scanning list and ensures
1729 * that other asynchronous scans started after this one won't affect the
1730 * ordering of the discovered devices.
1731 */
1732static struct async_scan_data *scsi_prep_async_scan(struct Scsi_Host *shost)
1733{
1734	struct async_scan_data *data;
1735	unsigned long flags;
1736
1737	if (strncmp(scsi_scan_type, "sync", 4) == 0)
1738		return NULL;
1739
1740	if (shost->async_scan) {
1741		printk("%s called twice for host %d", __func__,
1742				shost->host_no);
1743		dump_stack();
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		printk("%s called twice for host %d", __func__,
1796				shost->host_no);
1797		dump_stack();
1798		mutex_unlock(&shost->scan_mutex);
1799		return;
1800	}
1801
1802	wait_for_completion(&data->prev_finished);
1803
1804	scsi_sysfs_add_devices(shost);
1805
1806	spin_lock_irqsave(shost->host_lock, flags);
1807	shost->async_scan = 0;
1808	spin_unlock_irqrestore(shost->host_lock, flags);
1809
1810	mutex_unlock(&shost->scan_mutex);
1811
1812	spin_lock(&async_scan_lock);
1813	list_del(&data->list);
1814	if (!list_empty(&scanning_hosts)) {
1815		struct async_scan_data *next = list_entry(scanning_hosts.next,
1816				struct async_scan_data, list);
1817		complete(&next->prev_finished);
1818	}
1819	spin_unlock(&async_scan_lock);
1820
 
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 int do_scan_async(void *_data)
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	scsi_autopm_put_host(shost);
1848	return 0;
1849}
1850
1851/**
1852 * scsi_scan_host - scan the given adapter
1853 * @shost:	adapter to scan
1854 **/
1855void scsi_scan_host(struct Scsi_Host *shost)
1856{
1857	struct task_struct *p;
1858	struct async_scan_data *data;
1859
1860	if (strncmp(scsi_scan_type, "none", 4) == 0)
 
1861		return;
1862	if (scsi_autopm_get_host(shost) < 0)
1863		return;
1864
1865	data = scsi_prep_async_scan(shost);
1866	if (!data) {
1867		do_scsi_scan_host(shost);
1868		scsi_autopm_put_host(shost);
1869		return;
1870	}
1871
1872	p = kthread_run(do_scan_async, data, "scsi_scan_%d", shost->host_no);
1873	if (IS_ERR(p))
1874		do_scan_async(data);
1875	/* scsi_autopm_put_host(shost) is called in do_scan_async() */
 
 
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