1// SPDX-License-Identifier: GPL-2.0
   2/*
   3 * scsi_scan.c
   4 *
   5 * Copyright (C) 2000 Eric Youngdale,
   6 * Copyright (C) 2002 Patrick Mansfield
   7 *
   8 * The general scanning/probing algorithm is as follows, exceptions are
   9 * made to it depending on device specific flags, compilation options, and
  10 * global variable (boot or module load time) settings.
  11 *
  12 * A specific LUN is scanned via an INQUIRY command; if the LUN has a
  13 * device attached, a scsi_device is allocated and setup for it.
  14 *
  15 * For every id of every channel on the given host:
  16 *
  17 * 	Scan LUN 0; if the target responds to LUN 0 (even if there is no
  18 * 	device or storage attached to LUN 0):
  19 *
  20 * 		If LUN 0 has a device attached, allocate and setup a
  21 * 		scsi_device for it.
  22 *
  23 * 		If target is SCSI-3 or up, issue a REPORT LUN, and scan
  24 * 		all of the LUNs returned by the REPORT LUN; else,
  25 * 		sequentially scan LUNs up until some maximum is reached,
  26 * 		or a LUN is seen that cannot have a device attached to it.
  27 */
  28
  29#include <linux/module.h>
  30#include <linux/moduleparam.h>
  31#include <linux/init.h>
  32#include <linux/blkdev.h>
  33#include <linux/delay.h>
  34#include <linux/kthread.h>
  35#include <linux/spinlock.h>
  36#include <linux/async.h>
  37#include <linux/slab.h>
  38#include <linux/unaligned.h>
  39
  40#include <scsi/scsi.h>
  41#include <scsi/scsi_cmnd.h>
  42#include <scsi/scsi_device.h>
  43#include <scsi/scsi_driver.h>
  44#include <scsi/scsi_devinfo.h>
  45#include <scsi/scsi_host.h>
  46#include <scsi/scsi_transport.h>
  47#include <scsi/scsi_dh.h>
  48#include <scsi/scsi_eh.h>
  49
  50#include "scsi_priv.h"
  51#include "scsi_logging.h"
  52
  53#define ALLOC_FAILURE_MSG	KERN_ERR "%s: Allocation failure during" \
  54	" SCSI scanning, some SCSI devices might not be configured\n"
  55
  56/*
  57 * Default timeout
  58 */
  59#define SCSI_TIMEOUT (2*HZ)
  60#define SCSI_REPORT_LUNS_TIMEOUT (30*HZ)
  61
  62/*
  63 * Prefix values for the SCSI id's (stored in sysfs name field)
  64 */
  65#define SCSI_UID_SER_NUM 'S'
  66#define SCSI_UID_UNKNOWN 'Z'
  67
  68/*
  69 * Return values of some of the scanning functions.
  70 *
  71 * SCSI_SCAN_NO_RESPONSE: no valid response received from the target, this
  72 * includes allocation or general failures preventing IO from being sent.
  73 *
  74 * SCSI_SCAN_TARGET_PRESENT: target responded, but no device is available
  75 * on the given LUN.
  76 *
  77 * SCSI_SCAN_LUN_PRESENT: target responded, and a device is available on a
  78 * given LUN.
  79 */
  80#define SCSI_SCAN_NO_RESPONSE		0
  81#define SCSI_SCAN_TARGET_PRESENT	1
  82#define SCSI_SCAN_LUN_PRESENT		2
  83
  84static const char *scsi_null_device_strs = "nullnullnullnull";
  85
  86#define MAX_SCSI_LUNS	512
  87
  88static u64 max_scsi_luns = MAX_SCSI_LUNS;
  89
  90module_param_named(max_luns, max_scsi_luns, ullong, S_IRUGO|S_IWUSR);
  91MODULE_PARM_DESC(max_luns,
  92		 "last scsi LUN (should be between 1 and 2^64-1)");
  93
  94#ifdef CONFIG_SCSI_SCAN_ASYNC
  95#define SCSI_SCAN_TYPE_DEFAULT "async"
  96#else
  97#define SCSI_SCAN_TYPE_DEFAULT "sync"
  98#endif
  99
 100static char scsi_scan_type[7] = SCSI_SCAN_TYPE_DEFAULT;
 101
 102module_param_string(scan, scsi_scan_type, sizeof(scsi_scan_type),
 103		    S_IRUGO|S_IWUSR);
 104MODULE_PARM_DESC(scan, "sync, async, manual, or none. "
 105		 "Setting to 'manual' disables automatic scanning, but allows "
 106		 "for manual device scan via the 'scan' sysfs attribute.");
 107
 108static unsigned int scsi_inq_timeout = SCSI_TIMEOUT/HZ + 18;
 109
 110module_param_named(inq_timeout, scsi_inq_timeout, uint, S_IRUGO|S_IWUSR);
 111MODULE_PARM_DESC(inq_timeout, 
 112		 "Timeout (in seconds) waiting for devices to answer INQUIRY."
 113		 " Default is 20. Some devices may need more; most need less.");
 114
 115/* This lock protects only this list */
 116static DEFINE_SPINLOCK(async_scan_lock);
 117static LIST_HEAD(scanning_hosts);
 118
 119struct async_scan_data {
 120	struct list_head list;
 121	struct Scsi_Host *shost;
 122	struct completion prev_finished;
 123};
 124
 125/*
 126 * scsi_enable_async_suspend - Enable async suspend and resume
 127 */
 128void scsi_enable_async_suspend(struct device *dev)
 129{
 130	/*
 131	 * If a user has disabled async probing a likely reason is due to a
 132	 * storage enclosure that does not inject staggered spin-ups. For
 133	 * safety, make resume synchronous as well in that case.
 134	 */
 135	if (strncmp(scsi_scan_type, "async", 5) != 0)
 136		return;
 137	/* Enable asynchronous suspend and resume. */
 138	device_enable_async_suspend(dev);
 139}
 140
 141/**
 142 * scsi_complete_async_scans - Wait for asynchronous scans to complete
 143 *
 144 * When this function returns, any host which started scanning before
 145 * this function was called will have finished its scan.  Hosts which
 146 * started scanning after this function was called may or may not have
 147 * finished.
 148 */
 149int scsi_complete_async_scans(void)
 150{
 151	struct async_scan_data *data;
 152
 153	do {
 154		if (list_empty(&scanning_hosts))
 155			return 0;
 156		/* If we can't get memory immediately, that's OK.  Just
 157		 * sleep a little.  Even if we never get memory, the async
 158		 * scans will finish eventually.
 159		 */
 160		data = kmalloc(sizeof(*data), GFP_KERNEL);
 161		if (!data)
 162			msleep(1);
 163	} while (!data);
 164
 165	data->shost = NULL;
 166	init_completion(&data->prev_finished);
 167
 168	spin_lock(&async_scan_lock);
 169	/* Check that there's still somebody else on the list */
 170	if (list_empty(&scanning_hosts))
 171		goto done;
 172	list_add_tail(&data->list, &scanning_hosts);
 173	spin_unlock(&async_scan_lock);
 174
 175	printk(KERN_INFO "scsi: waiting for bus probes to complete ...\n");
 176	wait_for_completion(&data->prev_finished);
 177
 178	spin_lock(&async_scan_lock);
 179	list_del(&data->list);
 180	if (!list_empty(&scanning_hosts)) {
 181		struct async_scan_data *next = list_entry(scanning_hosts.next,
 182				struct async_scan_data, list);
 183		complete(&next->prev_finished);
 184	}
 185 done:
 186	spin_unlock(&async_scan_lock);
 187
 188	kfree(data);
 189	return 0;
 190}
 191
 192/**
 193 * scsi_unlock_floptical - unlock device via a special MODE SENSE command
 194 * @sdev:	scsi device to send command to
 195 * @result:	area to store the result of the MODE SENSE
 196 *
 197 * Description:
 198 *     Send a vendor specific MODE SENSE (not a MODE SELECT) command.
 199 *     Called for BLIST_KEY devices.
 200 **/
 201static void scsi_unlock_floptical(struct scsi_device *sdev,
 202				  unsigned char *result)
 203{
 204	unsigned char scsi_cmd[MAX_COMMAND_SIZE];
 205
 206	sdev_printk(KERN_NOTICE, sdev, "unlocking floptical drive\n");
 207	scsi_cmd[0] = MODE_SENSE;
 208	scsi_cmd[1] = 0;
 209	scsi_cmd[2] = 0x2e;
 210	scsi_cmd[3] = 0;
 211	scsi_cmd[4] = 0x2a;     /* size */
 212	scsi_cmd[5] = 0;
 213	scsi_execute_cmd(sdev, scsi_cmd, REQ_OP_DRV_IN, result, 0x2a,
 214			 SCSI_TIMEOUT, 3, NULL);
 215}
 216
 217static int scsi_realloc_sdev_budget_map(struct scsi_device *sdev,
 218					unsigned int depth)
 219{
 220	int new_shift = sbitmap_calculate_shift(depth);
 221	bool need_alloc = !sdev->budget_map.map;
 222	bool need_free = false;
 223	int ret;
 224	struct sbitmap sb_backup;
 225
 226	depth = min_t(unsigned int, depth, scsi_device_max_queue_depth(sdev));
 227
 228	/*
 229	 * realloc if new shift is calculated, which is caused by setting
 230	 * up one new default queue depth after calling ->device_configure
 231	 */
 232	if (!need_alloc && new_shift != sdev->budget_map.shift)
 233		need_alloc = need_free = true;
 234
 235	if (!need_alloc)
 236		return 0;
 237
 238	/*
 239	 * Request queue has to be frozen for reallocating budget map,
 240	 * and here disk isn't added yet, so freezing is pretty fast
 241	 */
 242	if (need_free) {
 243		blk_mq_freeze_queue(sdev->request_queue);
 244		sb_backup = sdev->budget_map;
 245	}
 246	ret = sbitmap_init_node(&sdev->budget_map,
 247				scsi_device_max_queue_depth(sdev),
 248				new_shift, GFP_KERNEL,
 249				sdev->request_queue->node, false, true);
 250	if (!ret)
 251		sbitmap_resize(&sdev->budget_map, depth);
 252
 253	if (need_free) {
 254		if (ret)
 255			sdev->budget_map = sb_backup;
 256		else
 257			sbitmap_free(&sb_backup);
 258		ret = 0;
 259		blk_mq_unfreeze_queue(sdev->request_queue);
 260	}
 261	return ret;
 262}
 263
 264/**
 265 * scsi_alloc_sdev - allocate and setup a scsi_Device
 266 * @starget: which target to allocate a &scsi_device for
 267 * @lun: which lun
 268 * @hostdata: usually NULL and set by ->slave_alloc instead
 269 *
 270 * Description:
 271 *     Allocate, initialize for io, and return a pointer to a scsi_Device.
 272 *     Stores the @shost, @channel, @id, and @lun in the scsi_Device, and
 273 *     adds scsi_Device to the appropriate list.
 274 *
 275 * Return value:
 276 *     scsi_Device pointer, or NULL on failure.
 277 **/
 278static struct scsi_device *scsi_alloc_sdev(struct scsi_target *starget,
 279					   u64 lun, void *hostdata)
 280{
 281	unsigned int depth;
 282	struct scsi_device *sdev;
 283	struct request_queue *q;
 284	int display_failure_msg = 1, ret;
 285	struct Scsi_Host *shost = dev_to_shost(starget->dev.parent);
 286	struct queue_limits lim;
 287
 288	sdev = kzalloc(sizeof(*sdev) + shost->transportt->device_size,
 289		       GFP_KERNEL);
 290	if (!sdev)
 291		goto out;
 292
 293	sdev->vendor = scsi_null_device_strs;
 294	sdev->model = scsi_null_device_strs;
 295	sdev->rev = scsi_null_device_strs;
 296	sdev->host = shost;
 297	sdev->queue_ramp_up_period = SCSI_DEFAULT_RAMP_UP_PERIOD;
 298	sdev->id = starget->id;
 299	sdev->lun = lun;
 300	sdev->channel = starget->channel;
 301	mutex_init(&sdev->state_mutex);
 302	sdev->sdev_state = SDEV_CREATED;
 303	INIT_LIST_HEAD(&sdev->siblings);
 304	INIT_LIST_HEAD(&sdev->same_target_siblings);
 
 305	INIT_LIST_HEAD(&sdev->starved_entry);
 306	INIT_LIST_HEAD(&sdev->event_list);
 307	spin_lock_init(&sdev->list_lock);
 308	mutex_init(&sdev->inquiry_mutex);
 309	INIT_WORK(&sdev->event_work, scsi_evt_thread);
 310	INIT_WORK(&sdev->requeue_work, scsi_requeue_run_queue);
 311
 312	sdev->sdev_gendev.parent = get_device(&starget->dev);
 313	sdev->sdev_target = starget;
 314
 315	/* usually NULL and set by ->slave_alloc instead */
 316	sdev->hostdata = hostdata;
 317
 318	/* if the device needs this changing, it may do so in the
 319	 * slave_configure function */
 320	sdev->max_device_blocked = SCSI_DEFAULT_DEVICE_BLOCKED;
 321
 322	/*
 323	 * Some low level driver could use device->type
 324	 */
 325	sdev->type = -1;
 326
 327	/*
 328	 * Assume that the device will have handshaking problems,
 329	 * and then fix this field later if it turns out it
 330	 * doesn't
 331	 */
 332	sdev->borken = 1;
 333
 334	sdev->sg_reserved_size = INT_MAX;
 335
 336	scsi_init_limits(shost, &lim);
 337	q = blk_mq_alloc_queue(&sdev->host->tag_set, &lim, sdev);
 338	if (IS_ERR(q)) {
 339		/* release fn is set up in scsi_sysfs_device_initialise, so
 340		 * have to free and put manually here */
 341		put_device(&starget->dev);
 342		kfree(sdev);
 343		goto out;
 344	}
 345	kref_get(&sdev->host->tagset_refcnt);
 346	sdev->request_queue = q;
 347
 348	depth = sdev->host->cmd_per_lun ?: 1;
 349
 350	/*
 351	 * Use .can_queue as budget map's depth because we have to
 352	 * support adjusting queue depth from sysfs. Meantime use
 353	 * default device queue depth to figure out sbitmap shift
 354	 * since we use this queue depth most of times.
 355	 */
 356	if (scsi_realloc_sdev_budget_map(sdev, depth)) {
 357		put_device(&starget->dev);
 358		kfree(sdev);
 359		goto out;
 360	}
 361
 362	scsi_change_queue_depth(sdev, depth);
 363
 364	scsi_sysfs_device_initialize(sdev);
 365
 366	if (shost->hostt->slave_alloc) {
 367		ret = shost->hostt->slave_alloc(sdev);
 368		if (ret) {
 369			/*
 370			 * if LLDD reports slave not present, don't clutter
 371			 * console with alloc failure messages
 372			 */
 373			if (ret == -ENXIO)
 374				display_failure_msg = 0;
 375			goto out_device_destroy;
 376		}
 377	}
 378
 379	return sdev;
 380
 381out_device_destroy:
 382	__scsi_remove_device(sdev);
 383out:
 384	if (display_failure_msg)
 385		printk(ALLOC_FAILURE_MSG, __func__);
 386	return NULL;
 387}
 388
 389static void scsi_target_destroy(struct scsi_target *starget)
 390{
 391	struct device *dev = &starget->dev;
 392	struct Scsi_Host *shost = dev_to_shost(dev->parent);
 393	unsigned long flags;
 394
 395	BUG_ON(starget->state == STARGET_DEL);
 396	starget->state = STARGET_DEL;
 397	transport_destroy_device(dev);
 398	spin_lock_irqsave(shost->host_lock, flags);
 399	if (shost->hostt->target_destroy)
 400		shost->hostt->target_destroy(starget);
 401	list_del_init(&starget->siblings);
 402	spin_unlock_irqrestore(shost->host_lock, flags);
 403	put_device(dev);
 404}
 405
 406static void scsi_target_dev_release(struct device *dev)
 407{
 408	struct device *parent = dev->parent;
 409	struct scsi_target *starget = to_scsi_target(dev);
 410
 411	kfree(starget);
 412	put_device(parent);
 413}
 414
 415static const struct device_type scsi_target_type = {
 416	.name =		"scsi_target",
 417	.release =	scsi_target_dev_release,
 418};
 419
 420int scsi_is_target_device(const struct device *dev)
 421{
 422	return dev->type == &scsi_target_type;
 423}
 424EXPORT_SYMBOL(scsi_is_target_device);
 425
 426static struct scsi_target *__scsi_find_target(struct device *parent,
 427					      int channel, uint id)
 428{
 429	struct scsi_target *starget, *found_starget = NULL;
 430	struct Scsi_Host *shost = dev_to_shost(parent);
 431	/*
 432	 * Search for an existing target for this sdev.
 433	 */
 434	list_for_each_entry(starget, &shost->__targets, siblings) {
 435		if (starget->id == id &&
 436		    starget->channel == channel) {
 437			found_starget = starget;
 438			break;
 439		}
 440	}
 441	if (found_starget)
 442		get_device(&found_starget->dev);
 443
 444	return found_starget;
 445}
 446
 447/**
 448 * scsi_target_reap_ref_release - remove target from visibility
 449 * @kref: the reap_ref in the target being released
 450 *
 451 * Called on last put of reap_ref, which is the indication that no device
 452 * under this target is visible anymore, so render the target invisible in
 453 * sysfs.  Note: we have to be in user context here because the target reaps
 454 * should be done in places where the scsi device visibility is being removed.
 455 */
 456static void scsi_target_reap_ref_release(struct kref *kref)
 457{
 458	struct scsi_target *starget
 459		= container_of(kref, struct scsi_target, reap_ref);
 460
 461	/*
 462	 * if we get here and the target is still in a CREATED state that
 463	 * means it was allocated but never made visible (because a scan
 464	 * turned up no LUNs), so don't call device_del() on it.
 465	 */
 466	if ((starget->state != STARGET_CREATED) &&
 467	    (starget->state != STARGET_CREATED_REMOVE)) {
 468		transport_remove_device(&starget->dev);
 469		device_del(&starget->dev);
 470	}
 471	scsi_target_destroy(starget);
 472}
 473
 474static void scsi_target_reap_ref_put(struct scsi_target *starget)
 475{
 476	kref_put(&starget->reap_ref, scsi_target_reap_ref_release);
 477}
 478
 479/**
 480 * scsi_alloc_target - allocate a new or find an existing target
 481 * @parent:	parent of the target (need not be a scsi host)
 482 * @channel:	target channel number (zero if no channels)
 483 * @id:		target id number
 484 *
 485 * Return an existing target if one exists, provided it hasn't already
 486 * gone into STARGET_DEL state, otherwise allocate a new target.
 487 *
 488 * The target is returned with an incremented reference, so the caller
 489 * is responsible for both reaping and doing a last put
 490 */
 491static struct scsi_target *scsi_alloc_target(struct device *parent,
 492					     int channel, uint id)
 493{
 494	struct Scsi_Host *shost = dev_to_shost(parent);
 495	struct device *dev = NULL;
 496	unsigned long flags;
 497	const int size = sizeof(struct scsi_target)
 498		+ shost->transportt->target_size;
 499	struct scsi_target *starget;
 500	struct scsi_target *found_target;
 501	int error, ref_got;
 502
 503	starget = kzalloc(size, GFP_KERNEL);
 504	if (!starget) {
 505		printk(KERN_ERR "%s: allocation failure\n", __func__);
 506		return NULL;
 507	}
 508	dev = &starget->dev;
 509	device_initialize(dev);
 510	kref_init(&starget->reap_ref);
 511	dev->parent = get_device(parent);
 512	dev_set_name(dev, "target%d:%d:%d", shost->host_no, channel, id);
 513	dev->bus = &scsi_bus_type;
 514	dev->type = &scsi_target_type;
 515	scsi_enable_async_suspend(dev);
 516	starget->id = id;
 517	starget->channel = channel;
 518	starget->can_queue = 0;
 519	INIT_LIST_HEAD(&starget->siblings);
 520	INIT_LIST_HEAD(&starget->devices);
 521	starget->state = STARGET_CREATED;
 522	starget->scsi_level = SCSI_2;
 523	starget->max_target_blocked = SCSI_DEFAULT_TARGET_BLOCKED;
 524 retry:
 525	spin_lock_irqsave(shost->host_lock, flags);
 526
 527	found_target = __scsi_find_target(parent, channel, id);
 528	if (found_target)
 529		goto found;
 530
 531	list_add_tail(&starget->siblings, &shost->__targets);
 532	spin_unlock_irqrestore(shost->host_lock, flags);
 533	/* allocate and add */
 534	transport_setup_device(dev);
 535	if (shost->hostt->target_alloc) {
 536		error = shost->hostt->target_alloc(starget);
 537
 538		if(error) {
 539			if (error != -ENXIO)
 540				dev_err(dev, "target allocation failed, error %d\n", error);
 541			/* don't want scsi_target_reap to do the final
 542			 * put because it will be under the host lock */
 543			scsi_target_destroy(starget);
 544			return NULL;
 545		}
 546	}
 547	get_device(dev);
 548
 549	return starget;
 550
 551 found:
 552	/*
 553	 * release routine already fired if kref is zero, so if we can still
 554	 * take the reference, the target must be alive.  If we can't, it must
 555	 * be dying and we need to wait for a new target
 556	 */
 557	ref_got = kref_get_unless_zero(&found_target->reap_ref);
 558
 559	spin_unlock_irqrestore(shost->host_lock, flags);
 560	if (ref_got) {
 561		put_device(dev);
 562		return found_target;
 563	}
 564	/*
 565	 * Unfortunately, we found a dying target; need to wait until it's
 566	 * dead before we can get a new one.  There is an anomaly here.  We
 567	 * *should* call scsi_target_reap() to balance the kref_get() of the
 568	 * reap_ref above.  However, since the target being released, it's
 569	 * already invisible and the reap_ref is irrelevant.  If we call
 570	 * scsi_target_reap() we might spuriously do another device_del() on
 571	 * an already invisible target.
 572	 */
 573	put_device(&found_target->dev);
 574	/*
 575	 * length of time is irrelevant here, we just want to yield the CPU
 576	 * for a tick to avoid busy waiting for the target to die.
 577	 */
 578	msleep(1);
 579	goto retry;
 580}
 581
 582/**
 583 * scsi_target_reap - check to see if target is in use and destroy if not
 584 * @starget: target to be checked
 585 *
 586 * This is used after removing a LUN or doing a last put of the target
 587 * it checks atomically that nothing is using the target and removes
 588 * it if so.
 589 */
 590void scsi_target_reap(struct scsi_target *starget)
 591{
 592	/*
 593	 * serious problem if this triggers: STARGET_DEL is only set in the if
 594	 * the reap_ref drops to zero, so we're trying to do another final put
 595	 * on an already released kref
 596	 */
 597	BUG_ON(starget->state == STARGET_DEL);
 598	scsi_target_reap_ref_put(starget);
 599}
 600
 601/**
 602 * scsi_sanitize_inquiry_string - remove non-graphical chars from an
 603 *                                INQUIRY result string
 604 * @s: INQUIRY result string to sanitize
 605 * @len: length of the string
 606 *
 607 * Description:
 608 *	The SCSI spec says that INQUIRY vendor, product, and revision
 609 *	strings must consist entirely of graphic ASCII characters,
 610 *	padded on the right with spaces.  Since not all devices obey
 611 *	this rule, we will replace non-graphic or non-ASCII characters
 612 *	with spaces.  Exception: a NUL character is interpreted as a
 613 *	string terminator, so all the following characters are set to
 614 *	spaces.
 615 **/
 616void scsi_sanitize_inquiry_string(unsigned char *s, int len)
 617{
 618	int terminated = 0;
 619
 620	for (; len > 0; (--len, ++s)) {
 621		if (*s == 0)
 622			terminated = 1;
 623		if (terminated || *s < 0x20 || *s > 0x7e)
 624			*s = ' ';
 625	}
 626}
 627EXPORT_SYMBOL(scsi_sanitize_inquiry_string);
 628
 629
 630/**
 631 * scsi_probe_lun - probe a single LUN using a SCSI INQUIRY
 632 * @sdev:	scsi_device to probe
 633 * @inq_result:	area to store the INQUIRY result
 634 * @result_len: len of inq_result
 635 * @bflags:	store any bflags found here
 636 *
 637 * Description:
 638 *     Probe the lun associated with @req using a standard SCSI INQUIRY;
 639 *
 640 *     If the INQUIRY is successful, zero is returned and the
 641 *     INQUIRY data is in @inq_result; the scsi_level and INQUIRY length
 642 *     are copied to the scsi_device any flags value is stored in *@bflags.
 643 **/
 644static int scsi_probe_lun(struct scsi_device *sdev, unsigned char *inq_result,
 645			  int result_len, blist_flags_t *bflags)
 646{
 647	unsigned char scsi_cmd[MAX_COMMAND_SIZE];
 648	int first_inquiry_len, try_inquiry_len, next_inquiry_len;
 649	int response_len = 0;
 650	int pass, count, result, resid;
 651	struct scsi_failure failure_defs[] = {
 652		/*
 653		 * not-ready to ready transition [asc/ascq=0x28/0x0] or
 654		 * power-on, reset [asc/ascq=0x29/0x0], continue. INQUIRY
 655		 * should not yield UNIT_ATTENTION but many buggy devices do
 656		 * so anyway.
 657		 */
 658		{
 659			.sense = UNIT_ATTENTION,
 660			.asc = 0x28,
 661			.result = SAM_STAT_CHECK_CONDITION,
 662		},
 663		{
 664			.sense = UNIT_ATTENTION,
 665			.asc = 0x29,
 666			.result = SAM_STAT_CHECK_CONDITION,
 667		},
 668		{
 669			.allowed = 1,
 670			.result = DID_TIME_OUT << 16,
 671		},
 672		{}
 673	};
 674	struct scsi_failures failures = {
 675		.total_allowed = 3,
 676		.failure_definitions = failure_defs,
 677	};
 678	const struct scsi_exec_args exec_args = {
 679		.resid = &resid,
 680		.failures = &failures,
 681	};
 682
 683	*bflags = 0;
 684
 685	/* Perform up to 3 passes.  The first pass uses a conservative
 686	 * transfer length of 36 unless sdev->inquiry_len specifies a
 687	 * different value. */
 688	first_inquiry_len = sdev->inquiry_len ? sdev->inquiry_len : 36;
 689	try_inquiry_len = first_inquiry_len;
 690	pass = 1;
 691
 692 next_pass:
 693	SCSI_LOG_SCAN_BUS(3, sdev_printk(KERN_INFO, sdev,
 694				"scsi scan: INQUIRY pass %d length %d\n",
 695				pass, try_inquiry_len));
 696
 697	/* Each pass gets up to three chances to ignore Unit Attention */
 698	scsi_failures_reset_retries(&failures);
 699
 700	for (count = 0; count < 3; ++count) {
 
 
 701		memset(scsi_cmd, 0, 6);
 702		scsi_cmd[0] = INQUIRY;
 703		scsi_cmd[4] = (unsigned char) try_inquiry_len;
 704
 705		memset(inq_result, 0, try_inquiry_len);
 706
 707		result = scsi_execute_cmd(sdev,  scsi_cmd, REQ_OP_DRV_IN,
 708					  inq_result, try_inquiry_len,
 709					  HZ / 2 + HZ * scsi_inq_timeout, 3,
 710					  &exec_args);
 711
 712		SCSI_LOG_SCAN_BUS(3, sdev_printk(KERN_INFO, sdev,
 713				"scsi scan: INQUIRY %s with code 0x%x\n",
 714				result ? "failed" : "successful", result));
 715
 716		if (result == 0) {
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 717			/*
 718			 * if nothing was transferred, we try
 719			 * again. It's a workaround for some USB
 720			 * devices.
 721			 */
 722			if (resid == try_inquiry_len)
 723				continue;
 724		}
 725		break;
 726	}
 727
 728	if (result == 0) {
 729		scsi_sanitize_inquiry_string(&inq_result[8], 8);
 730		scsi_sanitize_inquiry_string(&inq_result[16], 16);
 731		scsi_sanitize_inquiry_string(&inq_result[32], 4);
 732
 733		response_len = inq_result[4] + 5;
 734		if (response_len > 255)
 735			response_len = first_inquiry_len;	/* sanity */
 736
 737		/*
 738		 * Get any flags for this device.
 739		 *
 740		 * XXX add a bflags to scsi_device, and replace the
 741		 * corresponding bit fields in scsi_device, so bflags
 742		 * need not be passed as an argument.
 743		 */
 744		*bflags = scsi_get_device_flags(sdev, &inq_result[8],
 745				&inq_result[16]);
 746
 747		/* When the first pass succeeds we gain information about
 748		 * what larger transfer lengths might work. */
 749		if (pass == 1) {
 750			if (BLIST_INQUIRY_36 & *bflags)
 751				next_inquiry_len = 36;
 752			/*
 753			 * LLD specified a maximum sdev->inquiry_len
 754			 * but device claims it has more data. Capping
 755			 * the length only makes sense for legacy
 756			 * devices. If a device supports SPC-4 (2014)
 757			 * or newer, assume that it is safe to ask for
 758			 * as much as the device says it supports.
 759			 */
 760			else if (sdev->inquiry_len &&
 761				 response_len > sdev->inquiry_len &&
 762				 (inq_result[2] & 0x7) < 6) /* SPC-4 */
 763				next_inquiry_len = sdev->inquiry_len;
 764			else
 765				next_inquiry_len = response_len;
 766
 767			/* If more data is available perform the second pass */
 768			if (next_inquiry_len > try_inquiry_len) {
 769				try_inquiry_len = next_inquiry_len;
 770				pass = 2;
 771				goto next_pass;
 772			}
 773		}
 774
 775	} else if (pass == 2) {
 776		sdev_printk(KERN_INFO, sdev,
 777			    "scsi scan: %d byte inquiry failed.  "
 778			    "Consider BLIST_INQUIRY_36 for this device\n",
 779			    try_inquiry_len);
 780
 781		/* If this pass failed, the third pass goes back and transfers
 782		 * the same amount as we successfully got in the first pass. */
 783		try_inquiry_len = first_inquiry_len;
 784		pass = 3;
 785		goto next_pass;
 786	}
 787
 788	/* If the last transfer attempt got an error, assume the
 789	 * peripheral doesn't exist or is dead. */
 790	if (result)
 791		return -EIO;
 792
 793	/* Don't report any more data than the device says is valid */
 794	sdev->inquiry_len = min(try_inquiry_len, response_len);
 795
 796	/*
 797	 * XXX Abort if the response length is less than 36? If less than
 798	 * 32, the lookup of the device flags (above) could be invalid,
 799	 * and it would be possible to take an incorrect action - we do
 800	 * not want to hang because of a short INQUIRY. On the flip side,
 801	 * if the device is spun down or becoming ready (and so it gives a
 802	 * short INQUIRY), an abort here prevents any further use of the
 803	 * device, including spin up.
 804	 *
 805	 * On the whole, the best approach seems to be to assume the first
 806	 * 36 bytes are valid no matter what the device says.  That's
 807	 * better than copying < 36 bytes to the inquiry-result buffer
 808	 * and displaying garbage for the Vendor, Product, or Revision
 809	 * strings.
 810	 */
 811	if (sdev->inquiry_len < 36) {
 812		if (!sdev->host->short_inquiry) {
 813			shost_printk(KERN_INFO, sdev->host,
 814				    "scsi scan: INQUIRY result too short (%d),"
 815				    " using 36\n", sdev->inquiry_len);
 816			sdev->host->short_inquiry = 1;
 817		}
 818		sdev->inquiry_len = 36;
 819	}
 820
 821	/*
 822	 * Related to the above issue:
 823	 *
 824	 * XXX Devices (disk or all?) should be sent a TEST UNIT READY,
 825	 * and if not ready, sent a START_STOP to start (maybe spin up) and
 826	 * then send the INQUIRY again, since the INQUIRY can change after
 827	 * a device is initialized.
 828	 *
 829	 * Ideally, start a device if explicitly asked to do so.  This
 830	 * assumes that a device is spun up on power on, spun down on
 831	 * request, and then spun up on request.
 832	 */
 833
 834	/*
 835	 * The scanning code needs to know the scsi_level, even if no
 836	 * device is attached at LUN 0 (SCSI_SCAN_TARGET_PRESENT) so
 837	 * non-zero LUNs can be scanned.
 838	 */
 839	sdev->scsi_level = inq_result[2] & 0x0f;
 840	if (sdev->scsi_level >= 2 ||
 841	    (sdev->scsi_level == 1 && (inq_result[3] & 0x0f) == 1))
 842		sdev->scsi_level++;
 843	sdev->sdev_target->scsi_level = sdev->scsi_level;
 844
 845	/*
 846	 * If SCSI-2 or lower, and if the transport requires it,
 847	 * store the LUN value in CDB[1].
 848	 */
 849	sdev->lun_in_cdb = 0;
 850	if (sdev->scsi_level <= SCSI_2 &&
 851	    sdev->scsi_level != SCSI_UNKNOWN &&
 852	    !sdev->host->no_scsi2_lun_in_cdb)
 853		sdev->lun_in_cdb = 1;
 854
 855	return 0;
 856}
 857
 858/**
 859 * scsi_add_lun - allocate and fully initialze a scsi_device
 860 * @sdev:	holds information to be stored in the new scsi_device
 861 * @inq_result:	holds the result of a previous INQUIRY to the LUN
 862 * @bflags:	black/white list flag
 863 * @async:	1 if this device is being scanned asynchronously
 864 *
 865 * Description:
 866 *     Initialize the scsi_device @sdev.  Optionally set fields based
 867 *     on values in *@bflags.
 868 *
 869 * Return:
 870 *     SCSI_SCAN_NO_RESPONSE: could not allocate or setup a scsi_device
 871 *     SCSI_SCAN_LUN_PRESENT: a new scsi_device was allocated and initialized
 872 **/
 873static int scsi_add_lun(struct scsi_device *sdev, unsigned char *inq_result,
 874		blist_flags_t *bflags, int async)
 875{
 876	const struct scsi_host_template *hostt = sdev->host->hostt;
 877	struct queue_limits lim;
 878	int ret;
 879
 880	/*
 881	 * XXX do not save the inquiry, since it can change underneath us,
 882	 * save just vendor/model/rev.
 883	 *
 884	 * Rather than save it and have an ioctl that retrieves the saved
 885	 * value, have an ioctl that executes the same INQUIRY code used
 886	 * in scsi_probe_lun, let user level programs doing INQUIRY
 887	 * scanning run at their own risk, or supply a user level program
 888	 * that can correctly scan.
 889	 */
 890
 891	/*
 892	 * Copy at least 36 bytes of INQUIRY data, so that we don't
 893	 * dereference unallocated memory when accessing the Vendor,
 894	 * Product, and Revision strings.  Badly behaved devices may set
 895	 * the INQUIRY Additional Length byte to a small value, indicating
 896	 * these strings are invalid, but often they contain plausible data
 897	 * nonetheless.  It doesn't matter if the device sent < 36 bytes
 898	 * total, since scsi_probe_lun() initializes inq_result with 0s.
 899	 */
 900	sdev->inquiry = kmemdup(inq_result,
 901				max_t(size_t, sdev->inquiry_len, 36),
 902				GFP_KERNEL);
 903	if (sdev->inquiry == NULL)
 904		return SCSI_SCAN_NO_RESPONSE;
 905
 906	sdev->vendor = (char *) (sdev->inquiry + 8);
 907	sdev->model = (char *) (sdev->inquiry + 16);
 908	sdev->rev = (char *) (sdev->inquiry + 32);
 909
 910	if (strncmp(sdev->vendor, "ATA     ", 8) == 0) {
 911		/*
 912		 * sata emulation layer device.  This is a hack to work around
 913		 * the SATL power management specifications which state that
 914		 * when the SATL detects the device has gone into standby
 915		 * mode, it shall respond with NOT READY.
 916		 */
 917		sdev->allow_restart = 1;
 918	}
 919
 920	if (*bflags & BLIST_ISROM) {
 921		sdev->type = TYPE_ROM;
 922		sdev->removable = 1;
 923	} else {
 924		sdev->type = (inq_result[0] & 0x1f);
 925		sdev->removable = (inq_result[1] & 0x80) >> 7;
 926
 927		/*
 928		 * some devices may respond with wrong type for
 929		 * well-known logical units. Force well-known type
 930		 * to enumerate them correctly.
 931		 */
 932		if (scsi_is_wlun(sdev->lun) && sdev->type != TYPE_WLUN) {
 933			sdev_printk(KERN_WARNING, sdev,
 934				"%s: correcting incorrect peripheral device type 0x%x for W-LUN 0x%16xhN\n",
 935				__func__, sdev->type, (unsigned int)sdev->lun);
 936			sdev->type = TYPE_WLUN;
 937		}
 938
 939	}
 940
 941	if (sdev->type == TYPE_RBC || sdev->type == TYPE_ROM) {
 942		/* RBC and MMC devices can return SCSI-3 compliance and yet
 943		 * still not support REPORT LUNS, so make them act as
 944		 * BLIST_NOREPORTLUN unless BLIST_REPORTLUN2 is
 945		 * specifically set */
 946		if ((*bflags & BLIST_REPORTLUN2) == 0)
 947			*bflags |= BLIST_NOREPORTLUN;
 948	}
 949
 950	/*
 951	 * For a peripheral qualifier (PQ) value of 1 (001b), the SCSI
 952	 * spec says: The device server is capable of supporting the
 953	 * specified peripheral device type on this logical unit. However,
 954	 * the physical device is not currently connected to this logical
 955	 * unit.
 956	 *
 957	 * The above is vague, as it implies that we could treat 001 and
 958	 * 011 the same. Stay compatible with previous code, and create a
 959	 * scsi_device for a PQ of 1
 960	 *
 961	 * Don't set the device offline here; rather let the upper
 962	 * level drivers eval the PQ to decide whether they should
 963	 * attach. So remove ((inq_result[0] >> 5) & 7) == 1 check.
 964	 */ 
 965
 966	sdev->inq_periph_qual = (inq_result[0] >> 5) & 7;
 967	sdev->lockable = sdev->removable;
 968	sdev->soft_reset = (inq_result[7] & 1) && ((inq_result[3] & 7) == 2);
 969
 970	if (sdev->scsi_level >= SCSI_3 ||
 971			(sdev->inquiry_len > 56 && inq_result[56] & 0x04))
 972		sdev->ppr = 1;
 973	if (inq_result[7] & 0x60)
 974		sdev->wdtr = 1;
 975	if (inq_result[7] & 0x10)
 976		sdev->sdtr = 1;
 977
 978	sdev_printk(KERN_NOTICE, sdev, "%s %.8s %.16s %.4s PQ: %d "
 979			"ANSI: %d%s\n", scsi_device_type(sdev->type),
 980			sdev->vendor, sdev->model, sdev->rev,
 981			sdev->inq_periph_qual, inq_result[2] & 0x07,
 982			(inq_result[3] & 0x0f) == 1 ? " CCS" : "");
 983
 984	if ((sdev->scsi_level >= SCSI_2) && (inq_result[7] & 2) &&
 985	    !(*bflags & BLIST_NOTQ)) {
 986		sdev->tagged_supported = 1;
 987		sdev->simple_tags = 1;
 988	}
 989
 990	/*
 991	 * Some devices (Texel CD ROM drives) have handshaking problems
 992	 * when used with the Seagate controllers. borken is initialized
 993	 * to 1, and then set it to 0 here.
 994	 */
 995	if ((*bflags & BLIST_BORKEN) == 0)
 996		sdev->borken = 0;
 997
 998	if (*bflags & BLIST_NO_ULD_ATTACH)
 999		sdev->no_uld_attach = 1;
1000
1001	/*
1002	 * Apparently some really broken devices (contrary to the SCSI
1003	 * standards) need to be selected without asserting ATN
1004	 */
1005	if (*bflags & BLIST_SELECT_NO_ATN)
1006		sdev->select_no_atn = 1;
1007
1008	/*
 
 
 
 
 
 
 
 
 
 
 
 
 
1009	 * Some devices may not want to have a start command automatically
1010	 * issued when a device is added.
1011	 */
1012	if (*bflags & BLIST_NOSTARTONADD)
1013		sdev->no_start_on_add = 1;
1014
1015	if (*bflags & BLIST_SINGLELUN)
1016		scsi_target(sdev)->single_lun = 1;
1017
1018	sdev->use_10_for_rw = 1;
1019
1020	/* some devices don't like REPORT SUPPORTED OPERATION CODES
1021	 * and will simply timeout causing sd_mod init to take a very
1022	 * very long time */
1023	if (*bflags & BLIST_NO_RSOC)
1024		sdev->no_report_opcodes = 1;
1025
1026	/* set the device running here so that slave configure
1027	 * may do I/O */
1028	mutex_lock(&sdev->state_mutex);
1029	ret = scsi_device_set_state(sdev, SDEV_RUNNING);
1030	if (ret)
1031		ret = scsi_device_set_state(sdev, SDEV_BLOCK);
1032	mutex_unlock(&sdev->state_mutex);
1033
1034	if (ret) {
1035		sdev_printk(KERN_ERR, sdev,
1036			    "in wrong state %s to complete scan\n",
1037			    scsi_device_state_name(sdev->sdev_state));
1038		return SCSI_SCAN_NO_RESPONSE;
1039	}
1040
1041	if (*bflags & BLIST_NOT_LOCKABLE)
1042		sdev->lockable = 0;
1043
1044	if (*bflags & BLIST_RETRY_HWERROR)
1045		sdev->retry_hwerror = 1;
1046
1047	if (*bflags & BLIST_NO_DIF)
1048		sdev->no_dif = 1;
1049
1050	if (*bflags & BLIST_UNMAP_LIMIT_WS)
1051		sdev->unmap_limit_for_ws = 1;
1052
1053	if (*bflags & BLIST_IGN_MEDIA_CHANGE)
1054		sdev->ignore_media_change = 1;
1055
1056	sdev->eh_timeout = SCSI_DEFAULT_EH_TIMEOUT;
1057
1058	if (*bflags & BLIST_TRY_VPD_PAGES)
1059		sdev->try_vpd_pages = 1;
1060	else if (*bflags & BLIST_SKIP_VPD_PAGES)
1061		sdev->skip_vpd_pages = 1;
1062
1063	if (*bflags & BLIST_NO_VPD_SIZE)
1064		sdev->no_vpd_size = 1;
1065
1066	transport_configure_device(&sdev->sdev_gendev);
1067
1068	/*
1069	 * No need to freeze the queue as it isn't reachable to anyone else yet.
1070	 */
1071	lim = queue_limits_start_update(sdev->request_queue);
1072	if (*bflags & BLIST_MAX_512)
1073		lim.max_hw_sectors = 512;
1074	else if (*bflags & BLIST_MAX_1024)
1075		lim.max_hw_sectors = 1024;
1076
1077	if (hostt->device_configure)
1078		ret = hostt->device_configure(sdev, &lim);
1079	else if (hostt->slave_configure)
1080		ret = hostt->slave_configure(sdev);
1081	if (ret) {
1082		queue_limits_cancel_update(sdev->request_queue);
1083		/*
1084		 * If the LLDD reports device not present, don't clutter the
1085		 * console with failure messages.
1086		 */
1087		if (ret != -ENXIO)
1088			sdev_printk(KERN_ERR, sdev,
1089				"failed to configure device\n");
1090		return SCSI_SCAN_NO_RESPONSE;
1091	}
1092
1093	ret = queue_limits_commit_update(sdev->request_queue, &lim);
1094	if (ret) {
1095		sdev_printk(KERN_ERR, sdev, "failed to apply queue limits.\n");
1096		return SCSI_SCAN_NO_RESPONSE;
1097	}
1098
1099	/*
1100	 * The queue_depth is often changed in ->device_configure.
1101	 *
1102	 * Set up budget map again since memory consumption of the map depends
1103	 * on actual queue depth.
1104	 */
1105	if (hostt->device_configure || hostt->slave_configure)
1106		scsi_realloc_sdev_budget_map(sdev, sdev->queue_depth);
1107
1108	if (sdev->scsi_level >= SCSI_3)
1109		scsi_attach_vpd(sdev);
1110
1111	scsi_cdl_check(sdev);
1112
1113	sdev->max_queue_depth = sdev->queue_depth;
1114	WARN_ON_ONCE(sdev->max_queue_depth > sdev->budget_map.depth);
1115	sdev->sdev_bflags = *bflags;
1116
1117	/*
1118	 * Ok, the device is now all set up, we can
1119	 * register it and tell the rest of the kernel
1120	 * about it.
1121	 */
1122	if (!async && scsi_sysfs_add_sdev(sdev) != 0)
1123		return SCSI_SCAN_NO_RESPONSE;
1124
1125	return SCSI_SCAN_LUN_PRESENT;
1126}
1127
1128#ifdef CONFIG_SCSI_LOGGING
1129/** 
1130 * scsi_inq_str - print INQUIRY data from min to max index, strip trailing whitespace
1131 * @buf:   Output buffer with at least end-first+1 bytes of space
1132 * @inq:   Inquiry buffer (input)
1133 * @first: Offset of string into inq
1134 * @end:   Index after last character in inq
1135 */
1136static unsigned char *scsi_inq_str(unsigned char *buf, unsigned char *inq,
1137				   unsigned first, unsigned end)
1138{
1139	unsigned term = 0, idx;
1140
1141	for (idx = 0; idx + first < end && idx + first < inq[4] + 5; idx++) {
1142		if (inq[idx+first] > ' ') {
1143			buf[idx] = inq[idx+first];
1144			term = idx+1;
1145		} else {
1146			buf[idx] = ' ';
1147		}
1148	}
1149	buf[term] = 0;
1150	return buf;
1151}
1152#endif
1153
1154/**
1155 * scsi_probe_and_add_lun - probe a LUN, if a LUN is found add it
1156 * @starget:	pointer to target device structure
1157 * @lun:	LUN of target device
1158 * @bflagsp:	store bflags here if not NULL
1159 * @sdevp:	probe the LUN corresponding to this scsi_device
1160 * @rescan:     if not equal to SCSI_SCAN_INITIAL skip some code only
1161 *              needed on first scan
1162 * @hostdata:	passed to scsi_alloc_sdev()
1163 *
1164 * Description:
1165 *     Call scsi_probe_lun, if a LUN with an attached device is found,
1166 *     allocate and set it up by calling scsi_add_lun.
1167 *
1168 * Return:
1169 *
1170 *   - SCSI_SCAN_NO_RESPONSE: could not allocate or setup a scsi_device
1171 *   - SCSI_SCAN_TARGET_PRESENT: target responded, but no device is
1172 *         attached at the LUN
1173 *   - SCSI_SCAN_LUN_PRESENT: a new scsi_device was allocated and initialized
1174 **/
1175static int scsi_probe_and_add_lun(struct scsi_target *starget,
1176				  u64 lun, blist_flags_t *bflagsp,
1177				  struct scsi_device **sdevp,
1178				  enum scsi_scan_mode rescan,
1179				  void *hostdata)
1180{
1181	struct scsi_device *sdev;
1182	unsigned char *result;
1183	blist_flags_t bflags;
1184	int res = SCSI_SCAN_NO_RESPONSE, result_len = 256;
1185	struct Scsi_Host *shost = dev_to_shost(starget->dev.parent);
1186
1187	/*
1188	 * The rescan flag is used as an optimization, the first scan of a
1189	 * host adapter calls into here with rescan == 0.
1190	 */
1191	sdev = scsi_device_lookup_by_target(starget, lun);
1192	if (sdev) {
1193		if (rescan != SCSI_SCAN_INITIAL || !scsi_device_created(sdev)) {
1194			SCSI_LOG_SCAN_BUS(3, sdev_printk(KERN_INFO, sdev,
1195				"scsi scan: device exists on %s\n",
1196				dev_name(&sdev->sdev_gendev)));
1197			if (sdevp)
1198				*sdevp = sdev;
1199			else
1200				scsi_device_put(sdev);
1201
1202			if (bflagsp)
1203				*bflagsp = scsi_get_device_flags(sdev,
1204								 sdev->vendor,
1205								 sdev->model);
1206			return SCSI_SCAN_LUN_PRESENT;
1207		}
1208		scsi_device_put(sdev);
1209	} else
1210		sdev = scsi_alloc_sdev(starget, lun, hostdata);
1211	if (!sdev)
1212		goto out;
1213
1214	result = kmalloc(result_len, GFP_KERNEL);
 
1215	if (!result)
1216		goto out_free_sdev;
1217
1218	if (scsi_probe_lun(sdev, result, result_len, &bflags))
1219		goto out_free_result;
1220
1221	if (bflagsp)
1222		*bflagsp = bflags;
1223	/*
1224	 * result contains valid SCSI INQUIRY data.
1225	 */
1226	if ((result[0] >> 5) == 3) {
1227		/*
1228		 * For a Peripheral qualifier 3 (011b), the SCSI
1229		 * spec says: The device server is not capable of
1230		 * supporting a physical device on this logical
1231		 * unit.
1232		 *
1233		 * For disks, this implies that there is no
1234		 * logical disk configured at sdev->lun, but there
1235		 * is a target id responding.
1236		 */
1237		SCSI_LOG_SCAN_BUS(2, sdev_printk(KERN_INFO, sdev, "scsi scan:"
1238				   " peripheral qualifier of 3, device not"
1239				   " added\n"))
1240		if (lun == 0) {
1241			SCSI_LOG_SCAN_BUS(1, {
1242				unsigned char vend[9];
1243				unsigned char mod[17];
1244
1245				sdev_printk(KERN_INFO, sdev,
1246					"scsi scan: consider passing scsi_mod."
1247					"dev_flags=%s:%s:0x240 or 0x1000240\n",
1248					scsi_inq_str(vend, result, 8, 16),
1249					scsi_inq_str(mod, result, 16, 32));
1250			});
1251
1252		}
1253
1254		res = SCSI_SCAN_TARGET_PRESENT;
1255		goto out_free_result;
1256	}
1257
1258	/*
1259	 * Some targets may set slight variations of PQ and PDT to signal
1260	 * that no LUN is present, so don't add sdev in these cases.
1261	 * Two specific examples are:
1262	 * 1) NetApp targets: return PQ=1, PDT=0x1f
1263	 * 2) USB UFI: returns PDT=0x1f, with the PQ bits being "reserved"
1264	 *    in the UFI 1.0 spec (we cannot rely on reserved bits).
1265	 *
1266	 * References:
1267	 * 1) SCSI SPC-3, pp. 145-146
1268	 * PQ=1: "A peripheral device having the specified peripheral
1269	 * device type is not connected to this logical unit. However, the
1270	 * device server is capable of supporting the specified peripheral
1271	 * device type on this logical unit."
1272	 * PDT=0x1f: "Unknown or no device type"
1273	 * 2) USB UFI 1.0, p. 20
1274	 * PDT=00h Direct-access device (floppy)
1275	 * PDT=1Fh none (no FDD connected to the requested logical unit)
1276	 */
1277	if (((result[0] >> 5) == 1 || starget->pdt_1f_for_no_lun) &&
1278	    (result[0] & 0x1f) == 0x1f &&
1279	    !scsi_is_wlun(lun)) {
1280		SCSI_LOG_SCAN_BUS(3, sdev_printk(KERN_INFO, sdev,
1281					"scsi scan: peripheral device type"
1282					" of 31, no device added\n"));
1283		res = SCSI_SCAN_TARGET_PRESENT;
1284		goto out_free_result;
1285	}
1286
1287	res = scsi_add_lun(sdev, result, &bflags, shost->async_scan);
1288	if (res == SCSI_SCAN_LUN_PRESENT) {
1289		if (bflags & BLIST_KEY) {
1290			sdev->lockable = 0;
1291			scsi_unlock_floptical(sdev, result);
1292		}
1293	}
1294
1295 out_free_result:
1296	kfree(result);
1297 out_free_sdev:
1298	if (res == SCSI_SCAN_LUN_PRESENT) {
1299		if (sdevp) {
1300			if (scsi_device_get(sdev) == 0) {
1301				*sdevp = sdev;
1302			} else {
1303				__scsi_remove_device(sdev);
1304				res = SCSI_SCAN_NO_RESPONSE;
1305			}
1306		}
1307	} else
1308		__scsi_remove_device(sdev);
1309 out:
1310	return res;
1311}
1312
1313/**
1314 * scsi_sequential_lun_scan - sequentially scan a SCSI target
1315 * @starget:	pointer to target structure to scan
1316 * @bflags:	black/white list flag for LUN 0
1317 * @scsi_level: Which version of the standard does this device adhere to
1318 * @rescan:     passed to scsi_probe_add_lun()
1319 *
1320 * Description:
1321 *     Generally, scan from LUN 1 (LUN 0 is assumed to already have been
1322 *     scanned) to some maximum lun until a LUN is found with no device
1323 *     attached. Use the bflags to figure out any oddities.
1324 *
1325 *     Modifies sdevscan->lun.
1326 **/
1327static void scsi_sequential_lun_scan(struct scsi_target *starget,
1328				     blist_flags_t bflags, int scsi_level,
1329				     enum scsi_scan_mode rescan)
1330{
1331	uint max_dev_lun;
1332	u64 sparse_lun, lun;
1333	struct Scsi_Host *shost = dev_to_shost(starget->dev.parent);
1334
1335	SCSI_LOG_SCAN_BUS(3, starget_printk(KERN_INFO, starget,
1336		"scsi scan: Sequential scan\n"));
1337
1338	max_dev_lun = min(max_scsi_luns, shost->max_lun);
1339	/*
1340	 * If this device is known to support sparse multiple units,
1341	 * override the other settings, and scan all of them. Normally,
1342	 * SCSI-3 devices should be scanned via the REPORT LUNS.
1343	 */
1344	if (bflags & BLIST_SPARSELUN) {
1345		max_dev_lun = shost->max_lun;
1346		sparse_lun = 1;
1347	} else
1348		sparse_lun = 0;
1349
1350	/*
1351	 * If less than SCSI_1_CCS, and no special lun scanning, stop
1352	 * scanning; this matches 2.4 behaviour, but could just be a bug
1353	 * (to continue scanning a SCSI_1_CCS device).
1354	 *
1355	 * This test is broken.  We might not have any device on lun0 for
1356	 * a sparselun device, and if that's the case then how would we
1357	 * know the real scsi_level, eh?  It might make sense to just not
1358	 * scan any SCSI_1 device for non-0 luns, but that check would best
1359	 * go into scsi_alloc_sdev() and just have it return null when asked
1360	 * to alloc an sdev for lun > 0 on an already found SCSI_1 device.
1361	 *
1362	if ((sdevscan->scsi_level < SCSI_1_CCS) &&
1363	    ((bflags & (BLIST_FORCELUN | BLIST_SPARSELUN | BLIST_MAX5LUN))
1364	     == 0))
1365		return;
1366	 */
1367	/*
1368	 * If this device is known to support multiple units, override
1369	 * the other settings, and scan all of them.
1370	 */
1371	if (bflags & BLIST_FORCELUN)
1372		max_dev_lun = shost->max_lun;
1373	/*
1374	 * REGAL CDC-4X: avoid hang after LUN 4
1375	 */
1376	if (bflags & BLIST_MAX5LUN)
1377		max_dev_lun = min(5U, max_dev_lun);
1378	/*
1379	 * Do not scan SCSI-2 or lower device past LUN 7, unless
1380	 * BLIST_LARGELUN.
1381	 */
1382	if (scsi_level < SCSI_3 && !(bflags & BLIST_LARGELUN))
1383		max_dev_lun = min(8U, max_dev_lun);
1384	else
1385		max_dev_lun = min(256U, max_dev_lun);
1386
1387	/*
1388	 * We have already scanned LUN 0, so start at LUN 1. Keep scanning
1389	 * until we reach the max, or no LUN is found and we are not
1390	 * sparse_lun.
1391	 */
1392	for (lun = 1; lun < max_dev_lun; ++lun)
1393		if ((scsi_probe_and_add_lun(starget, lun, NULL, NULL, rescan,
1394					    NULL) != SCSI_SCAN_LUN_PRESENT) &&
1395		    !sparse_lun)
1396			return;
1397}
1398
1399/**
1400 * scsi_report_lun_scan - Scan using SCSI REPORT LUN results
1401 * @starget: which target
1402 * @bflags: Zero or a mix of BLIST_NOLUN, BLIST_REPORTLUN2, or BLIST_NOREPORTLUN
1403 * @rescan: nonzero if we can skip code only needed on first scan
1404 *
1405 * Description:
1406 *   Fast scanning for modern (SCSI-3) devices by sending a REPORT LUN command.
1407 *   Scan the resulting list of LUNs by calling scsi_probe_and_add_lun.
1408 *
1409 *   If BLINK_REPORTLUN2 is set, scan a target that supports more than 8
1410 *   LUNs even if it's older than SCSI-3.
1411 *   If BLIST_NOREPORTLUN is set, return 1 always.
1412 *   If BLIST_NOLUN is set, return 0 always.
1413 *   If starget->no_report_luns is set, return 1 always.
1414 *
1415 * Return:
1416 *     0: scan completed (or no memory, so further scanning is futile)
1417 *     1: could not scan with REPORT LUN
1418 **/
1419static int scsi_report_lun_scan(struct scsi_target *starget, blist_flags_t bflags,
1420				enum scsi_scan_mode rescan)
1421{
1422	unsigned char scsi_cmd[MAX_COMMAND_SIZE];
1423	unsigned int length;
1424	u64 lun;
1425	unsigned int num_luns;
 
1426	int result;
1427	struct scsi_lun *lunp, *lun_data;
 
1428	struct scsi_device *sdev;
1429	struct Scsi_Host *shost = dev_to_shost(&starget->dev);
1430	struct scsi_failure failure_defs[] = {
1431		{
1432			.sense = UNIT_ATTENTION,
1433			.asc = SCMD_FAILURE_ASC_ANY,
1434			.ascq = SCMD_FAILURE_ASCQ_ANY,
1435			.result = SAM_STAT_CHECK_CONDITION,
1436		},
1437		/* Fail all CCs except the UA above */
1438		{
1439			.sense = SCMD_FAILURE_SENSE_ANY,
1440			.result = SAM_STAT_CHECK_CONDITION,
1441		},
1442		/* Retry any other errors not listed above */
1443		{
1444			.result = SCMD_FAILURE_RESULT_ANY,
1445		},
1446		{}
1447	};
1448	struct scsi_failures failures = {
1449		.total_allowed = 3,
1450		.failure_definitions = failure_defs,
1451	};
1452	const struct scsi_exec_args exec_args = {
1453		.failures = &failures,
1454	};
1455	int ret = 0;
1456
1457	/*
1458	 * Only support SCSI-3 and up devices if BLIST_NOREPORTLUN is not set.
1459	 * Also allow SCSI-2 if BLIST_REPORTLUN2 is set and host adapter does
1460	 * support more than 8 LUNs.
1461	 * Don't attempt if the target doesn't support REPORT LUNS.
1462	 */
1463	if (bflags & BLIST_NOREPORTLUN)
1464		return 1;
1465	if (starget->scsi_level < SCSI_2 &&
1466	    starget->scsi_level != SCSI_UNKNOWN)
1467		return 1;
1468	if (starget->scsi_level < SCSI_3 &&
1469	    (!(bflags & BLIST_REPORTLUN2) || shost->max_lun <= 8))
1470		return 1;
1471	if (bflags & BLIST_NOLUN)
1472		return 0;
1473	if (starget->no_report_luns)
1474		return 1;
1475
1476	if (!(sdev = scsi_device_lookup_by_target(starget, 0))) {
1477		sdev = scsi_alloc_sdev(starget, 0, NULL);
1478		if (!sdev)
1479			return 0;
1480		if (scsi_device_get(sdev)) {
1481			__scsi_remove_device(sdev);
1482			return 0;
1483		}
1484	}
1485
1486	/*
1487	 * Allocate enough to hold the header (the same size as one scsi_lun)
1488	 * plus the number of luns we are requesting.  511 was the default
1489	 * value of the now removed max_report_luns parameter.
1490	 */
1491	length = (511 + 1) * sizeof(struct scsi_lun);
1492retry:
1493	lun_data = kmalloc(length, GFP_KERNEL);
 
1494	if (!lun_data) {
1495		printk(ALLOC_FAILURE_MSG, __func__);
1496		goto out;
1497	}
1498
1499	scsi_cmd[0] = REPORT_LUNS;
1500
1501	/*
1502	 * bytes 1 - 5: reserved, set to zero.
1503	 */
1504	memset(&scsi_cmd[1], 0, 5);
1505
1506	/*
1507	 * bytes 6 - 9: length of the command.
1508	 */
1509	put_unaligned_be32(length, &scsi_cmd[6]);
1510
1511	scsi_cmd[10] = 0;	/* reserved */
1512	scsi_cmd[11] = 0;	/* control */
1513
1514	/*
1515	 * We can get a UNIT ATTENTION, for example a power on/reset, so
1516	 * retry a few times (like sd.c does for TEST UNIT READY).
1517	 * Experience shows some combinations of adapter/devices get at
1518	 * least two power on/resets.
1519	 *
1520	 * Illegal requests (for devices that do not support REPORT LUNS)
1521	 * should come through as a check condition, and will not generate
1522	 * a retry.
1523	 */
1524	scsi_failures_reset_retries(&failures);
1525
1526	SCSI_LOG_SCAN_BUS(3, sdev_printk (KERN_INFO, sdev,
1527			  "scsi scan: Sending REPORT LUNS\n"));
1528
1529	result = scsi_execute_cmd(sdev, scsi_cmd, REQ_OP_DRV_IN, lun_data,
1530				  length, SCSI_REPORT_LUNS_TIMEOUT, 3,
1531				  &exec_args);
 
 
 
 
 
 
 
 
 
 
 
 
 
1532
1533	SCSI_LOG_SCAN_BUS(3, sdev_printk (KERN_INFO, sdev,
1534			  "scsi scan: REPORT LUNS  %s result 0x%x\n",
1535			  result ?  "failed" : "successful", result));
1536	if (result) {
1537		/*
1538		 * The device probably does not support a REPORT LUN command
1539		 */
1540		ret = 1;
1541		goto out_err;
1542	}
1543
1544	/*
1545	 * Get the length from the first four bytes of lun_data.
1546	 */
1547	if (get_unaligned_be32(lun_data->scsi_lun) +
1548	    sizeof(struct scsi_lun) > length) {
1549		length = get_unaligned_be32(lun_data->scsi_lun) +
1550			 sizeof(struct scsi_lun);
1551		kfree(lun_data);
1552		goto retry;
1553	}
1554	length = get_unaligned_be32(lun_data->scsi_lun);
1555
1556	num_luns = (length / sizeof(struct scsi_lun));
1557
1558	SCSI_LOG_SCAN_BUS(3, sdev_printk (KERN_INFO, sdev,
1559		"scsi scan: REPORT LUN scan\n"));
1560
1561	/*
1562	 * Scan the luns in lun_data. The entry at offset 0 is really
1563	 * the header, so start at 1 and go up to and including num_luns.
1564	 */
1565	for (lunp = &lun_data[1]; lunp <= &lun_data[num_luns]; lunp++) {
1566		lun = scsilun_to_int(lunp);
1567
1568		if (lun > sdev->host->max_lun) {
1569			sdev_printk(KERN_WARNING, sdev,
1570				    "lun%llu has a LUN larger than"
1571				    " allowed by the host adapter\n", lun);
1572		} else {
1573			int res;
1574
1575			res = scsi_probe_and_add_lun(starget,
1576				lun, NULL, NULL, rescan, NULL);
1577			if (res == SCSI_SCAN_NO_RESPONSE) {
1578				/*
1579				 * Got some results, but now none, abort.
1580				 */
1581				sdev_printk(KERN_ERR, sdev,
1582					"Unexpected response"
1583					" from lun %llu while scanning, scan"
1584					" aborted\n", (unsigned long long)lun);
1585				break;
1586			}
1587		}
1588	}
1589
1590 out_err:
1591	kfree(lun_data);
1592 out:
1593	if (scsi_device_created(sdev))
1594		/*
1595		 * the sdev we used didn't appear in the report luns scan
1596		 */
1597		__scsi_remove_device(sdev);
1598	scsi_device_put(sdev);
1599	return ret;
1600}
1601
1602struct scsi_device *__scsi_add_device(struct Scsi_Host *shost, uint channel,
1603				      uint id, u64 lun, void *hostdata)
1604{
1605	struct scsi_device *sdev = ERR_PTR(-ENODEV);
1606	struct device *parent = &shost->shost_gendev;
1607	struct scsi_target *starget;
1608
1609	if (strncmp(scsi_scan_type, "none", 4) == 0)
1610		return ERR_PTR(-ENODEV);
1611
1612	starget = scsi_alloc_target(parent, channel, id);
1613	if (!starget)
1614		return ERR_PTR(-ENOMEM);
1615	scsi_autopm_get_target(starget);
1616
1617	mutex_lock(&shost->scan_mutex);
1618	if (!shost->async_scan)
1619		scsi_complete_async_scans();
1620
1621	if (scsi_host_scan_allowed(shost) && scsi_autopm_get_host(shost) == 0) {
1622		scsi_probe_and_add_lun(starget, lun, NULL, &sdev,
1623				       SCSI_SCAN_RESCAN, hostdata);
1624		scsi_autopm_put_host(shost);
1625	}
1626	mutex_unlock(&shost->scan_mutex);
1627	scsi_autopm_put_target(starget);
1628	/*
1629	 * paired with scsi_alloc_target().  Target will be destroyed unless
1630	 * scsi_probe_and_add_lun made an underlying device visible
1631	 */
1632	scsi_target_reap(starget);
1633	put_device(&starget->dev);
1634
1635	return sdev;
1636}
1637EXPORT_SYMBOL(__scsi_add_device);
1638
1639int scsi_add_device(struct Scsi_Host *host, uint channel,
1640		    uint target, u64 lun)
1641{
1642	struct scsi_device *sdev = 
1643		__scsi_add_device(host, channel, target, lun, NULL);
1644	if (IS_ERR(sdev))
1645		return PTR_ERR(sdev);
1646
1647	scsi_device_put(sdev);
1648	return 0;
1649}
1650EXPORT_SYMBOL(scsi_add_device);
1651
1652int scsi_resume_device(struct scsi_device *sdev)
1653{
1654	struct device *dev = &sdev->sdev_gendev;
1655	int ret = 0;
1656
1657	device_lock(dev);
1658
1659	/*
1660	 * Bail out if the device or its queue are not running. Otherwise,
1661	 * the rescan may block waiting for commands to be executed, with us
1662	 * holding the device lock. This can result in a potential deadlock
1663	 * in the power management core code when system resume is on-going.
1664	 */
1665	if (sdev->sdev_state != SDEV_RUNNING ||
1666	    blk_queue_pm_only(sdev->request_queue)) {
1667		ret = -EWOULDBLOCK;
1668		goto unlock;
1669	}
1670
1671	if (dev->driver && try_module_get(dev->driver->owner)) {
1672		struct scsi_driver *drv = to_scsi_driver(dev->driver);
1673
1674		if (drv->resume)
1675			ret = drv->resume(dev);
1676		module_put(dev->driver->owner);
1677	}
1678
1679unlock:
1680	device_unlock(dev);
1681
1682	return ret;
1683}
1684EXPORT_SYMBOL(scsi_resume_device);
1685
1686int scsi_rescan_device(struct scsi_device *sdev)
1687{
1688	struct device *dev = &sdev->sdev_gendev;
1689	int ret = 0;
1690
1691	device_lock(dev);
1692
1693	/*
1694	 * Bail out if the device or its queue are not running. Otherwise,
1695	 * the rescan may block waiting for commands to be executed, with us
1696	 * holding the device lock. This can result in a potential deadlock
1697	 * in the power management core code when system resume is on-going.
1698	 */
1699	if (sdev->sdev_state != SDEV_RUNNING ||
1700	    blk_queue_pm_only(sdev->request_queue)) {
1701		ret = -EWOULDBLOCK;
1702		goto unlock;
1703	}
1704
1705	scsi_attach_vpd(sdev);
1706	scsi_cdl_check(sdev);
1707
1708	if (sdev->handler && sdev->handler->rescan)
1709		sdev->handler->rescan(sdev);
1710
1711	if (dev->driver && try_module_get(dev->driver->owner)) {
1712		struct scsi_driver *drv = to_scsi_driver(dev->driver);
1713
1714		if (drv->rescan)
1715			drv->rescan(dev);
1716		module_put(dev->driver->owner);
1717	}
1718
1719unlock:
1720	device_unlock(dev);
1721
1722	return ret;
1723}
1724EXPORT_SYMBOL(scsi_rescan_device);
1725
1726static void __scsi_scan_target(struct device *parent, unsigned int channel,
1727		unsigned int id, u64 lun, enum scsi_scan_mode rescan)
1728{
1729	struct Scsi_Host *shost = dev_to_shost(parent);
1730	blist_flags_t bflags = 0;
1731	int res;
1732	struct scsi_target *starget;
1733
1734	if (shost->this_id == id)
1735		/*
1736		 * Don't scan the host adapter
1737		 */
1738		return;
1739
1740	starget = scsi_alloc_target(parent, channel, id);
1741	if (!starget)
1742		return;
1743	scsi_autopm_get_target(starget);
1744
1745	if (lun != SCAN_WILD_CARD) {
1746		/*
1747		 * Scan for a specific host/chan/id/lun.
1748		 */
1749		scsi_probe_and_add_lun(starget, lun, NULL, NULL, rescan, NULL);
1750		goto out_reap;
1751	}
1752
1753	/*
1754	 * Scan LUN 0, if there is some response, scan further. Ideally, we
1755	 * would not configure LUN 0 until all LUNs are scanned.
1756	 */
1757	res = scsi_probe_and_add_lun(starget, 0, &bflags, NULL, rescan, NULL);
1758	if (res == SCSI_SCAN_LUN_PRESENT || res == SCSI_SCAN_TARGET_PRESENT) {
1759		if (scsi_report_lun_scan(starget, bflags, rescan) != 0)
1760			/*
1761			 * The REPORT LUN did not scan the target,
1762			 * do a sequential scan.
1763			 */
1764			scsi_sequential_lun_scan(starget, bflags,
1765						 starget->scsi_level, rescan);
1766	}
1767
1768 out_reap:
1769	scsi_autopm_put_target(starget);
1770	/*
1771	 * paired with scsi_alloc_target(): determine if the target has
1772	 * any children at all and if not, nuke it
1773	 */
1774	scsi_target_reap(starget);
1775
1776	put_device(&starget->dev);
1777}
1778
1779/**
1780 * scsi_scan_target - scan a target id, possibly including all LUNs on the target.
1781 * @parent:	host to scan
1782 * @channel:	channel to scan
1783 * @id:		target id to scan
1784 * @lun:	Specific LUN to scan or SCAN_WILD_CARD
1785 * @rescan:	passed to LUN scanning routines; SCSI_SCAN_INITIAL for
1786 *              no rescan, SCSI_SCAN_RESCAN to rescan existing LUNs,
1787 *              and SCSI_SCAN_MANUAL to force scanning even if
1788 *              'scan=manual' is set.
1789 *
1790 * Description:
1791 *     Scan the target id on @parent, @channel, and @id. Scan at least LUN 0,
1792 *     and possibly all LUNs on the target id.
1793 *
1794 *     First try a REPORT LUN scan, if that does not scan the target, do a
1795 *     sequential scan of LUNs on the target id.
1796 **/
1797void scsi_scan_target(struct device *parent, unsigned int channel,
1798		      unsigned int id, u64 lun, enum scsi_scan_mode rescan)
1799{
1800	struct Scsi_Host *shost = dev_to_shost(parent);
1801
1802	if (strncmp(scsi_scan_type, "none", 4) == 0)
1803		return;
1804
1805	if (rescan != SCSI_SCAN_MANUAL &&
1806	    strncmp(scsi_scan_type, "manual", 6) == 0)
1807		return;
1808
1809	mutex_lock(&shost->scan_mutex);
1810	if (!shost->async_scan)
1811		scsi_complete_async_scans();
1812
1813	if (scsi_host_scan_allowed(shost) && scsi_autopm_get_host(shost) == 0) {
1814		__scsi_scan_target(parent, channel, id, lun, rescan);
1815		scsi_autopm_put_host(shost);
1816	}
1817	mutex_unlock(&shost->scan_mutex);
1818}
1819EXPORT_SYMBOL(scsi_scan_target);
1820
1821static void scsi_scan_channel(struct Scsi_Host *shost, unsigned int channel,
1822			      unsigned int id, u64 lun,
1823			      enum scsi_scan_mode rescan)
1824{
1825	uint order_id;
1826
1827	if (id == SCAN_WILD_CARD)
1828		for (id = 0; id < shost->max_id; ++id) {
1829			/*
1830			 * XXX adapter drivers when possible (FCP, iSCSI)
1831			 * could modify max_id to match the current max,
1832			 * not the absolute max.
1833			 *
1834			 * XXX add a shost id iterator, so for example,
1835			 * the FC ID can be the same as a target id
1836			 * without a huge overhead of sparse id's.
1837			 */
1838			if (shost->reverse_ordering)
1839				/*
1840				 * Scan from high to low id.
1841				 */
1842				order_id = shost->max_id - id - 1;
1843			else
1844				order_id = id;
1845			__scsi_scan_target(&shost->shost_gendev, channel,
1846					order_id, lun, rescan);
1847		}
1848	else
1849		__scsi_scan_target(&shost->shost_gendev, channel,
1850				id, lun, rescan);
1851}
1852
1853int scsi_scan_host_selected(struct Scsi_Host *shost, unsigned int channel,
1854			    unsigned int id, u64 lun,
1855			    enum scsi_scan_mode rescan)
1856{
1857	SCSI_LOG_SCAN_BUS(3, shost_printk (KERN_INFO, shost,
1858		"%s: <%u:%u:%llu>\n",
1859		__func__, channel, id, lun));
1860
1861	if (((channel != SCAN_WILD_CARD) && (channel > shost->max_channel)) ||
1862	    ((id != SCAN_WILD_CARD) && (id >= shost->max_id)) ||
1863	    ((lun != SCAN_WILD_CARD) && (lun >= shost->max_lun)))
1864		return -EINVAL;
1865
1866	mutex_lock(&shost->scan_mutex);
1867	if (!shost->async_scan)
1868		scsi_complete_async_scans();
1869
1870	if (scsi_host_scan_allowed(shost) && scsi_autopm_get_host(shost) == 0) {
1871		if (channel == SCAN_WILD_CARD)
1872			for (channel = 0; channel <= shost->max_channel;
1873			     channel++)
1874				scsi_scan_channel(shost, channel, id, lun,
1875						  rescan);
1876		else
1877			scsi_scan_channel(shost, channel, id, lun, rescan);
1878		scsi_autopm_put_host(shost);
1879	}
1880	mutex_unlock(&shost->scan_mutex);
1881
1882	return 0;
1883}
1884
1885static void scsi_sysfs_add_devices(struct Scsi_Host *shost)
1886{
1887	struct scsi_device *sdev;
1888	shost_for_each_device(sdev, shost) {
1889		/* target removed before the device could be added */
1890		if (sdev->sdev_state == SDEV_DEL)
1891			continue;
1892		/* If device is already visible, skip adding it to sysfs */
1893		if (sdev->is_visible)
1894			continue;
1895		if (!scsi_host_scan_allowed(shost) ||
1896		    scsi_sysfs_add_sdev(sdev) != 0)
1897			__scsi_remove_device(sdev);
1898	}
1899}
1900
1901/**
1902 * scsi_prep_async_scan - prepare for an async scan
1903 * @shost: the host which will be scanned
1904 * Returns: a cookie to be passed to scsi_finish_async_scan()
1905 *
1906 * Tells the midlayer this host is going to do an asynchronous scan.
1907 * It reserves the host's position in the scanning list and ensures
1908 * that other asynchronous scans started after this one won't affect the
1909 * ordering of the discovered devices.
1910 */
1911static struct async_scan_data *scsi_prep_async_scan(struct Scsi_Host *shost)
1912{
1913	struct async_scan_data *data = NULL;
1914	unsigned long flags;
1915
1916	if (strncmp(scsi_scan_type, "sync", 4) == 0)
1917		return NULL;
1918
1919	mutex_lock(&shost->scan_mutex);
1920	if (shost->async_scan) {
1921		shost_printk(KERN_DEBUG, shost, "%s called twice\n", __func__);
1922		goto err;
1923	}
1924
1925	data = kmalloc(sizeof(*data), GFP_KERNEL);
1926	if (!data)
1927		goto err;
1928	data->shost = scsi_host_get(shost);
1929	if (!data->shost)
1930		goto err;
1931	init_completion(&data->prev_finished);
1932
 
1933	spin_lock_irqsave(shost->host_lock, flags);
1934	shost->async_scan = 1;
1935	spin_unlock_irqrestore(shost->host_lock, flags);
1936	mutex_unlock(&shost->scan_mutex);
1937
1938	spin_lock(&async_scan_lock);
1939	if (list_empty(&scanning_hosts))
1940		complete(&data->prev_finished);
1941	list_add_tail(&data->list, &scanning_hosts);
1942	spin_unlock(&async_scan_lock);
1943
1944	return data;
1945
1946 err:
1947	mutex_unlock(&shost->scan_mutex);
1948	kfree(data);
1949	return NULL;
1950}
1951
1952/**
1953 * scsi_finish_async_scan - asynchronous scan has finished
1954 * @data: cookie returned from earlier call to scsi_prep_async_scan()
1955 *
1956 * All the devices currently attached to this host have been found.
1957 * This function announces all the devices it has found to the rest
1958 * of the system.
1959 */
1960static void scsi_finish_async_scan(struct async_scan_data *data)
1961{
1962	struct Scsi_Host *shost;
1963	unsigned long flags;
1964
1965	if (!data)
1966		return;
1967
1968	shost = data->shost;
1969
1970	mutex_lock(&shost->scan_mutex);
1971
1972	if (!shost->async_scan) {
1973		shost_printk(KERN_INFO, shost, "%s called twice\n", __func__);
1974		dump_stack();
1975		mutex_unlock(&shost->scan_mutex);
1976		return;
1977	}
1978
1979	wait_for_completion(&data->prev_finished);
1980
1981	scsi_sysfs_add_devices(shost);
1982
1983	spin_lock_irqsave(shost->host_lock, flags);
1984	shost->async_scan = 0;
1985	spin_unlock_irqrestore(shost->host_lock, flags);
1986
1987	mutex_unlock(&shost->scan_mutex);
1988
1989	spin_lock(&async_scan_lock);
1990	list_del(&data->list);
1991	if (!list_empty(&scanning_hosts)) {
1992		struct async_scan_data *next = list_entry(scanning_hosts.next,
1993				struct async_scan_data, list);
1994		complete(&next->prev_finished);
1995	}
1996	spin_unlock(&async_scan_lock);
1997
1998	scsi_autopm_put_host(shost);
1999	scsi_host_put(shost);
2000	kfree(data);
2001}
2002
2003static void do_scsi_scan_host(struct Scsi_Host *shost)
2004{
2005	if (shost->hostt->scan_finished) {
2006		unsigned long start = jiffies;
2007		if (shost->hostt->scan_start)
2008			shost->hostt->scan_start(shost);
2009
2010		while (!shost->hostt->scan_finished(shost, jiffies - start))
2011			msleep(10);
2012	} else {
2013		scsi_scan_host_selected(shost, SCAN_WILD_CARD, SCAN_WILD_CARD,
2014				SCAN_WILD_CARD, SCSI_SCAN_INITIAL);
2015	}
2016}
2017
2018static void do_scan_async(void *_data, async_cookie_t c)
2019{
2020	struct async_scan_data *data = _data;
2021	struct Scsi_Host *shost = data->shost;
2022
2023	do_scsi_scan_host(shost);
2024	scsi_finish_async_scan(data);
2025}
2026
2027/**
2028 * scsi_scan_host - scan the given adapter
2029 * @shost:	adapter to scan
2030 **/
2031void scsi_scan_host(struct Scsi_Host *shost)
2032{
2033	struct async_scan_data *data;
2034
2035	if (strncmp(scsi_scan_type, "none", 4) == 0 ||
2036	    strncmp(scsi_scan_type, "manual", 6) == 0)
2037		return;
2038	if (scsi_autopm_get_host(shost) < 0)
2039		return;
2040
2041	data = scsi_prep_async_scan(shost);
2042	if (!data) {
2043		do_scsi_scan_host(shost);
2044		scsi_autopm_put_host(shost);
2045		return;
2046	}
2047
2048	/* register with the async subsystem so wait_for_device_probe()
2049	 * will flush this work
2050	 */
2051	async_schedule(do_scan_async, data);
2052
2053	/* scsi_autopm_put_host(shost) is called in scsi_finish_async_scan() */
2054}
2055EXPORT_SYMBOL(scsi_scan_host);
2056
2057void scsi_forget_host(struct Scsi_Host *shost)
2058{
2059	struct scsi_device *sdev;
2060	unsigned long flags;
2061
2062 restart:
2063	spin_lock_irqsave(shost->host_lock, flags);
2064	list_for_each_entry(sdev, &shost->__devices, siblings) {
2065		if (sdev->sdev_state == SDEV_DEL)
2066			continue;
2067		spin_unlock_irqrestore(shost->host_lock, flags);
2068		__scsi_remove_device(sdev);
2069		goto restart;
2070	}
2071	spin_unlock_irqrestore(shost->host_lock, flags);
2072}
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
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