linux/drivers/scsi/scsi_scan.c
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   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/**
 188 * scsi_unlock_floptical - unlock device via a special MODE SENSE command
 189 * @sdev:       scsi device to send command to
 190 * @result:     area to store the result of the MODE SENSE
 191 *
 192 * Description:
 193 *     Send a vendor specific MODE SENSE (not a MODE SELECT) command.
 194 *     Called for BLIST_KEY devices.
 195 **/
 196static void scsi_unlock_floptical(struct scsi_device *sdev,
 197                                  unsigned char *result)
 198{
 199        unsigned char scsi_cmd[MAX_COMMAND_SIZE];
 200
 201        printk(KERN_NOTICE "scsi: unlocking floptical drive\n");
 202        scsi_cmd[0] = MODE_SENSE;
 203        scsi_cmd[1] = 0;
 204        scsi_cmd[2] = 0x2e;
 205        scsi_cmd[3] = 0;
 206        scsi_cmd[4] = 0x2a;     /* size */
 207        scsi_cmd[5] = 0;
 208        scsi_execute_req(sdev, scsi_cmd, DMA_FROM_DEVICE, result, 0x2a, NULL,
 209                         SCSI_TIMEOUT, 3, NULL);
 210}
 211
 212/**
 213 * scsi_alloc_sdev - allocate and setup a scsi_Device
 214 * @starget: which target to allocate a &scsi_device for
 215 * @lun: which lun
 216 * @hostdata: usually NULL and set by ->slave_alloc instead
 217 *
 218 * Description:
 219 *     Allocate, initialize for io, and return a pointer to a scsi_Device.
 220 *     Stores the @shost, @channel, @id, and @lun in the scsi_Device, and
 221 *     adds scsi_Device to the appropriate list.
 222 *
 223 * Return value:
 224 *     scsi_Device pointer, or NULL on failure.
 225 **/
 226static struct scsi_device *scsi_alloc_sdev(struct scsi_target *starget,
 227                                           unsigned int lun, void *hostdata)
 228{
 229        struct scsi_device *sdev;
 230        int display_failure_msg = 1, ret;
 231        struct Scsi_Host *shost = dev_to_shost(starget->dev.parent);
 232        extern void scsi_evt_thread(struct work_struct *work);
 233        extern void scsi_requeue_run_queue(struct work_struct *work);
 234
 235        sdev = kzalloc(sizeof(*sdev) + shost->transportt->device_size,
 236                       GFP_ATOMIC);
 237        if (!sdev)
 238                goto out;
 239
 240        sdev->vendor = scsi_null_device_strs;
 241        sdev->model = scsi_null_device_strs;
 242        sdev->rev = scsi_null_device_strs;
 243        sdev->host = shost;
 244        sdev->queue_ramp_up_period = SCSI_DEFAULT_RAMP_UP_PERIOD;
 245        sdev->id = starget->id;
 246        sdev->lun = lun;
 247        sdev->channel = starget->channel;
 248        sdev->sdev_state = SDEV_CREATED;
 249        INIT_LIST_HEAD(&sdev->siblings);
 250        INIT_LIST_HEAD(&sdev->same_target_siblings);
 251        INIT_LIST_HEAD(&sdev->cmd_list);
 252        INIT_LIST_HEAD(&sdev->starved_entry);
 253        INIT_LIST_HEAD(&sdev->event_list);
 254        spin_lock_init(&sdev->list_lock);
 255        INIT_WORK(&sdev->event_work, scsi_evt_thread);
 256        INIT_WORK(&sdev->requeue_work, scsi_requeue_run_queue);
 257
 258        sdev->sdev_gendev.parent = get_device(&starget->dev);
 259        sdev->sdev_target = starget;
 260
 261        /* usually NULL and set by ->slave_alloc instead */
 262        sdev->hostdata = hostdata;
 263
 264        /* if the device needs this changing, it may do so in the
 265         * slave_configure function */
 266        sdev->max_device_blocked = SCSI_DEFAULT_DEVICE_BLOCKED;
 267
 268        /*
 269         * Some low level driver could use device->type
 270         */
 271        sdev->type = -1;
 272
 273        /*
 274         * Assume that the device will have handshaking problems,
 275         * and then fix this field later if it turns out it
 276         * doesn't
 277         */
 278        sdev->borken = 1;
 279
 280        sdev->request_queue = scsi_alloc_queue(sdev);
 281        if (!sdev->request_queue) {
 282                /* release fn is set up in scsi_sysfs_device_initialise, so
 283                 * have to free and put manually here */
 284                put_device(&starget->dev);
 285                kfree(sdev);
 286                goto out;
 287        }
 288        WARN_ON_ONCE(!blk_get_queue(sdev->request_queue));
 289        sdev->request_queue->queuedata = sdev;
 290        scsi_adjust_queue_depth(sdev, 0, sdev->host->cmd_per_lun);
 291
 292        scsi_sysfs_device_initialize(sdev);
 293
 294        if (shost->hostt->slave_alloc) {
 295                ret = shost->hostt->slave_alloc(sdev);
 296                if (ret) {
 297                        /*
 298                         * if LLDD reports slave not present, don't clutter
 299                         * console with alloc failure messages
 300                         */
 301                        if (ret == -ENXIO)
 302                                display_failure_msg = 0;
 303                        goto out_device_destroy;
 304                }
 305        }
 306
 307        return sdev;
 308
 309out_device_destroy:
 310        __scsi_remove_device(sdev);
 311out:
 312        if (display_failure_msg)
 313                printk(ALLOC_FAILURE_MSG, __func__);
 314        return NULL;
 315}
 316
 317static void scsi_target_destroy(struct scsi_target *starget)
 318{
 319        struct device *dev = &starget->dev;
 320        struct Scsi_Host *shost = dev_to_shost(dev->parent);
 321        unsigned long flags;
 322
 323        transport_destroy_device(dev);
 324        spin_lock_irqsave(shost->host_lock, flags);
 325        if (shost->hostt->target_destroy)
 326                shost->hostt->target_destroy(starget);
 327        list_del_init(&starget->siblings);
 328        spin_unlock_irqrestore(shost->host_lock, flags);
 329        put_device(dev);
 330}
 331
 332static void scsi_target_dev_release(struct device *dev)
 333{
 334        struct device *parent = dev->parent;
 335        struct scsi_target *starget = to_scsi_target(dev);
 336
 337        kfree(starget);
 338        put_device(parent);
 339}
 340
 341static struct device_type scsi_target_type = {
 342        .name =         "scsi_target",
 343        .release =      scsi_target_dev_release,
 344};
 345
 346int scsi_is_target_device(const struct device *dev)
 347{
 348        return dev->type == &scsi_target_type;
 349}
 350EXPORT_SYMBOL(scsi_is_target_device);
 351
 352static struct scsi_target *__scsi_find_target(struct device *parent,
 353                                              int channel, uint id)
 354{
 355        struct scsi_target *starget, *found_starget = NULL;
 356        struct Scsi_Host *shost = dev_to_shost(parent);
 357        /*
 358         * Search for an existing target for this sdev.
 359         */
 360        list_for_each_entry(starget, &shost->__targets, siblings) {
 361                if (starget->id == id &&
 362                    starget->channel == channel) {
 363                        found_starget = starget;
 364                        break;
 365                }
 366        }
 367        if (found_starget)
 368                get_device(&found_starget->dev);
 369
 370        return found_starget;
 371}
 372
 373/**
 374 * scsi_alloc_target - allocate a new or find an existing target
 375 * @parent:     parent of the target (need not be a scsi host)
 376 * @channel:    target channel number (zero if no channels)
 377 * @id:         target id number
 378 *
 379 * Return an existing target if one exists, provided it hasn't already
 380 * gone into STARGET_DEL state, otherwise allocate a new target.
 381 *
 382 * The target is returned with an incremented reference, so the caller
 383 * is responsible for both reaping and doing a last put
 384 */
 385static struct scsi_target *scsi_alloc_target(struct device *parent,
 386                                             int channel, uint id)
 387{
 388        struct Scsi_Host *shost = dev_to_shost(parent);
 389        struct device *dev = NULL;
 390        unsigned long flags;
 391        const int size = sizeof(struct scsi_target)
 392                + shost->transportt->target_size;
 393        struct scsi_target *starget;
 394        struct scsi_target *found_target;
 395        int error;
 396
 397        starget = kzalloc(size, GFP_KERNEL);
 398        if (!starget) {
 399                printk(KERN_ERR "%s: allocation failure\n", __func__);
 400                return NULL;
 401        }
 402        dev = &starget->dev;
 403        device_initialize(dev);
 404        starget->reap_ref = 1;
 405        dev->parent = get_device(parent);
 406        dev_set_name(dev, "target%d:%d:%d", shost->host_no, channel, id);
 407        dev->bus = &scsi_bus_type;
 408        dev->type = &scsi_target_type;
 409        starget->id = id;
 410        starget->channel = channel;
 411        starget->can_queue = 0;
 412        INIT_LIST_HEAD(&starget->siblings);
 413        INIT_LIST_HEAD(&starget->devices);
 414        starget->state = STARGET_CREATED;
 415        starget->scsi_level = SCSI_2;
 416        starget->max_target_blocked = SCSI_DEFAULT_TARGET_BLOCKED;
 417 retry:
 418        spin_lock_irqsave(shost->host_lock, flags);
 419
 420        found_target = __scsi_find_target(parent, channel, id);
 421        if (found_target)
 422                goto found;
 423
 424        list_add_tail(&starget->siblings, &shost->__targets);
 425        spin_unlock_irqrestore(shost->host_lock, flags);
 426        /* allocate and add */
 427        transport_setup_device(dev);
 428        if (shost->hostt->target_alloc) {
 429                error = shost->hostt->target_alloc(starget);
 430
 431                if(error) {
 432                        dev_printk(KERN_ERR, dev, "target allocation failed, error %d\n", error);
 433                        /* don't want scsi_target_reap to do the final
 434                         * put because it will be under the host lock */
 435                        scsi_target_destroy(starget);
 436                        return NULL;
 437                }
 438        }
 439        get_device(dev);
 440
 441        return starget;
 442
 443 found:
 444        found_target->reap_ref++;
 445        spin_unlock_irqrestore(shost->host_lock, flags);
 446        if (found_target->state != STARGET_DEL) {
 447                put_device(dev);
 448                return found_target;
 449        }
 450        /* Unfortunately, we found a dying target; need to
 451         * wait until it's dead before we can get a new one */
 452        put_device(&found_target->dev);
 453        flush_scheduled_work();
 454        goto retry;
 455}
 456
 457static void scsi_target_reap_usercontext(struct work_struct *work)
 458{
 459        struct scsi_target *starget =
 460                container_of(work, struct scsi_target, ew.work);
 461
 462        transport_remove_device(&starget->dev);
 463        device_del(&starget->dev);
 464        scsi_target_destroy(starget);
 465}
 466
 467/**
 468 * scsi_target_reap - check to see if target is in use and destroy if not
 469 * @starget: target to be checked
 470 *
 471 * This is used after removing a LUN or doing a last put of the target
 472 * it checks atomically that nothing is using the target and removes
 473 * it if so.
 474 */
 475void scsi_target_reap(struct scsi_target *starget)
 476{
 477        struct Scsi_Host *shost = dev_to_shost(starget->dev.parent);
 478        unsigned long flags;
 479        enum scsi_target_state state;
 480        int empty = 0;
 481
 482        spin_lock_irqsave(shost->host_lock, flags);
 483        state = starget->state;
 484        if (--starget->reap_ref == 0 && list_empty(&starget->devices)) {
 485                empty = 1;
 486                starget->state = STARGET_DEL;
 487        }
 488        spin_unlock_irqrestore(shost->host_lock, flags);
 489
 490        if (!empty)
 491                return;
 492
 493        BUG_ON(state == STARGET_DEL);
 494        if (state == STARGET_CREATED)
 495                scsi_target_destroy(starget);
 496        else
 497                execute_in_process_context(scsi_target_reap_usercontext,
 498                                           &starget->ew);
 499}
 500
 501/**
 502 * sanitize_inquiry_string - remove non-graphical chars from an INQUIRY result string
 503 * @s: INQUIRY result string to sanitize
 504 * @len: length of the string
 505 *
 506 * Description:
 507 *      The SCSI spec says that INQUIRY vendor, product, and revision
 508 *      strings must consist entirely of graphic ASCII characters,
 509 *      padded on the right with spaces.  Since not all devices obey
 510 *      this rule, we will replace non-graphic or non-ASCII characters
 511 *      with spaces.  Exception: a NUL character is interpreted as a
 512 *      string terminator, so all the following characters are set to
 513 *      spaces.
 514 **/
 515static void sanitize_inquiry_string(unsigned char *s, int len)
 516{
 517        int terminated = 0;
 518
 519        for (; len > 0; (--len, ++s)) {
 520                if (*s == 0)
 521                        terminated = 1;
 522                if (terminated || *s < 0x20 || *s > 0x7e)
 523                        *s = ' ';
 524        }
 525}
 526
 527/**
 528 * scsi_probe_lun - probe a single LUN using a SCSI INQUIRY
 529 * @sdev:       scsi_device to probe
 530 * @inq_result: area to store the INQUIRY result
 531 * @result_len: len of inq_result
 532 * @bflags:     store any bflags found here
 533 *
 534 * Description:
 535 *     Probe the lun associated with @req using a standard SCSI INQUIRY;
 536 *
 537 *     If the INQUIRY is successful, zero is returned and the
 538 *     INQUIRY data is in @inq_result; the scsi_level and INQUIRY length
 539 *     are copied to the scsi_device any flags value is stored in *@bflags.
 540 **/
 541static int scsi_probe_lun(struct scsi_device *sdev, unsigned char *inq_result,
 542                          int result_len, int *bflags)
 543{
 544        unsigned char scsi_cmd[MAX_COMMAND_SIZE];
 545        int first_inquiry_len, try_inquiry_len, next_inquiry_len;
 546        int response_len = 0;
 547        int pass, count, result;
 548        struct scsi_sense_hdr sshdr;
 549
 550        *bflags = 0;
 551
 552        /* Perform up to 3 passes.  The first pass uses a conservative
 553         * transfer length of 36 unless sdev->inquiry_len specifies a
 554         * different value. */
 555        first_inquiry_len = sdev->inquiry_len ? sdev->inquiry_len : 36;
 556        try_inquiry_len = first_inquiry_len;
 557        pass = 1;
 558
 559 next_pass:
 560        SCSI_LOG_SCAN_BUS(3, sdev_printk(KERN_INFO, sdev,
 561                                "scsi scan: INQUIRY pass %d length %d\n",
 562                                pass, try_inquiry_len));
 563
 564        /* Each pass gets up to three chances to ignore Unit Attention */
 565        for (count = 0; count < 3; ++count) {
 566                int resid;
 567
 568                memset(scsi_cmd, 0, 6);
 569                scsi_cmd[0] = INQUIRY;
 570                scsi_cmd[4] = (unsigned char) try_inquiry_len;
 571
 572                memset(inq_result, 0, try_inquiry_len);
 573
 574                result = scsi_execute_req(sdev,  scsi_cmd, DMA_FROM_DEVICE,
 575                                          inq_result, try_inquiry_len, &sshdr,
 576                                          HZ / 2 + HZ * scsi_inq_timeout, 3,
 577                                          &resid);
 578
 579                SCSI_LOG_SCAN_BUS(3, printk(KERN_INFO "scsi scan: INQUIRY %s "
 580                                "with code 0x%x\n",
 581                                result ? "failed" : "successful", result));
 582
 583                if (result) {
 584                        /*
 585                         * not-ready to ready transition [asc/ascq=0x28/0x0]
 586                         * or power-on, reset [asc/ascq=0x29/0x0], continue.
 587                         * INQUIRY should not yield UNIT_ATTENTION
 588                         * but many buggy devices do so anyway. 
 589                         */
 590                        if ((driver_byte(result) & DRIVER_SENSE) &&
 591                            scsi_sense_valid(&sshdr)) {
 592                                if ((sshdr.sense_key == UNIT_ATTENTION) &&
 593                                    ((sshdr.asc == 0x28) ||
 594                                     (sshdr.asc == 0x29)) &&
 595                                    (sshdr.ascq == 0))
 596                                        continue;
 597                        }
 598                } else {
 599                        /*
 600                         * if nothing was transferred, we try
 601                         * again. It's a workaround for some USB
 602                         * devices.
 603                         */
 604                        if (resid == try_inquiry_len)
 605                                continue;
 606                }
 607                break;
 608        }
 609
 610        if (result == 0) {
 611                sanitize_inquiry_string(&inq_result[8], 8);
 612                sanitize_inquiry_string(&inq_result[16], 16);
 613                sanitize_inquiry_string(&inq_result[32], 4);
 614
 615                response_len = inq_result[4] + 5;
 616                if (response_len > 255)
 617                        response_len = first_inquiry_len;       /* sanity */
 618
 619                /*
 620                 * Get any flags for this device.
 621                 *
 622                 * XXX add a bflags to scsi_device, and replace the
 623                 * corresponding bit fields in scsi_device, so bflags
 624                 * need not be passed as an argument.
 625                 */
 626                *bflags = scsi_get_device_flags(sdev, &inq_result[8],
 627                                &inq_result[16]);
 628
 629                /* When the first pass succeeds we gain information about
 630                 * what larger transfer lengths might work. */
 631                if (pass == 1) {
 632                        if (BLIST_INQUIRY_36 & *bflags)
 633                                next_inquiry_len = 36;
 634                        else if (BLIST_INQUIRY_58 & *bflags)
 635                                next_inquiry_len = 58;
 636                        else if (sdev->inquiry_len)
 637                                next_inquiry_len = sdev->inquiry_len;
 638                        else
 639                                next_inquiry_len = response_len;
 640
 641                        /* If more data is available perform the second pass */
 642                        if (next_inquiry_len > try_inquiry_len) {
 643                                try_inquiry_len = next_inquiry_len;
 644                                pass = 2;
 645                                goto next_pass;
 646                        }
 647                }
 648
 649        } else if (pass == 2) {
 650                printk(KERN_INFO "scsi scan: %d byte inquiry failed.  "
 651                                "Consider BLIST_INQUIRY_36 for this device\n",
 652                                try_inquiry_len);
 653
 654                /* If this pass failed, the third pass goes back and transfers
 655                 * the same amount as we successfully got in the first pass. */
 656                try_inquiry_len = first_inquiry_len;
 657                pass = 3;
 658                goto next_pass;
 659        }
 660
 661        /* If the last transfer attempt got an error, assume the
 662         * peripheral doesn't exist or is dead. */
 663        if (result)
 664                return -EIO;
 665
 666        /* Don't report any more data than the device says is valid */
 667        sdev->inquiry_len = min(try_inquiry_len, response_len);
 668
 669        /*
 670         * XXX Abort if the response length is less than 36? If less than
 671         * 32, the lookup of the device flags (above) could be invalid,
 672         * and it would be possible to take an incorrect action - we do
 673         * not want to hang because of a short INQUIRY. On the flip side,
 674         * if the device is spun down or becoming ready (and so it gives a
 675         * short INQUIRY), an abort here prevents any further use of the
 676         * device, including spin up.
 677         *
 678         * On the whole, the best approach seems to be to assume the first
 679         * 36 bytes are valid no matter what the device says.  That's
 680         * better than copying < 36 bytes to the inquiry-result buffer
 681         * and displaying garbage for the Vendor, Product, or Revision
 682         * strings.
 683         */
 684        if (sdev->inquiry_len < 36) {
 685                printk(KERN_INFO "scsi scan: INQUIRY result too short (%d),"
 686                                " using 36\n", sdev->inquiry_len);
 687                sdev->inquiry_len = 36;
 688        }
 689
 690        /*
 691         * Related to the above issue:
 692         *
 693         * XXX Devices (disk or all?) should be sent a TEST UNIT READY,
 694         * and if not ready, sent a START_STOP to start (maybe spin up) and
 695         * then send the INQUIRY again, since the INQUIRY can change after
 696         * a device is initialized.
 697         *
 698         * Ideally, start a device if explicitly asked to do so.  This
 699         * assumes that a device is spun up on power on, spun down on
 700         * request, and then spun up on request.
 701         */
 702
 703        /*
 704         * The scanning code needs to know the scsi_level, even if no
 705         * device is attached at LUN 0 (SCSI_SCAN_TARGET_PRESENT) so
 706         * non-zero LUNs can be scanned.
 707         */
 708        sdev->scsi_level = inq_result[2] & 0x07;
 709        if (sdev->scsi_level >= 2 ||
 710            (sdev->scsi_level == 1 && (inq_result[3] & 0x0f) == 1))
 711                sdev->scsi_level++;
 712        sdev->sdev_target->scsi_level = sdev->scsi_level;
 713
 714        return 0;
 715}
 716
 717/**
 718 * scsi_add_lun - allocate and fully initialze a scsi_device
 719 * @sdev:       holds information to be stored in the new scsi_device
 720 * @inq_result: holds the result of a previous INQUIRY to the LUN
 721 * @bflags:     black/white list flag
 722 * @async:      1 if this device is being scanned asynchronously
 723 *
 724 * Description:
 725 *     Initialize the scsi_device @sdev.  Optionally set fields based
 726 *     on values in *@bflags.
 727 *
 728 * Return:
 729 *     SCSI_SCAN_NO_RESPONSE: could not allocate or setup a scsi_device
 730 *     SCSI_SCAN_LUN_PRESENT: a new scsi_device was allocated and initialized
 731 **/
 732static int scsi_add_lun(struct scsi_device *sdev, unsigned char *inq_result,
 733                int *bflags, int async)
 734{
 735        int ret;
 736
 737        /*
 738         * XXX do not save the inquiry, since it can change underneath us,
 739         * save just vendor/model/rev.
 740         *
 741         * Rather than save it and have an ioctl that retrieves the saved
 742         * value, have an ioctl that executes the same INQUIRY code used
 743         * in scsi_probe_lun, let user level programs doing INQUIRY
 744         * scanning run at their own risk, or supply a user level program
 745         * that can correctly scan.
 746         */
 747
 748        /*
 749         * Copy at least 36 bytes of INQUIRY data, so that we don't
 750         * dereference unallocated memory when accessing the Vendor,
 751         * Product, and Revision strings.  Badly behaved devices may set
 752         * the INQUIRY Additional Length byte to a small value, indicating
 753         * these strings are invalid, but often they contain plausible data
 754         * nonetheless.  It doesn't matter if the device sent < 36 bytes
 755         * total, since scsi_probe_lun() initializes inq_result with 0s.
 756         */
 757        sdev->inquiry = kmemdup(inq_result,
 758                                max_t(size_t, sdev->inquiry_len, 36),
 759                                GFP_ATOMIC);
 760        if (sdev->inquiry == NULL)
 761                return SCSI_SCAN_NO_RESPONSE;
 762
 763        sdev->vendor = (char *) (sdev->inquiry + 8);
 764        sdev->model = (char *) (sdev->inquiry + 16);
 765        sdev->rev = (char *) (sdev->inquiry + 32);
 766
 767        if (strncmp(sdev->vendor, "ATA     ", 8) == 0) {
 768                /*
 769                 * sata emulation layer device.  This is a hack to work around
 770                 * the SATL power management specifications which state that
 771                 * when the SATL detects the device has gone into standby
 772                 * mode, it shall respond with NOT READY.
 773                 */
 774                sdev->allow_restart = 1;
 775        }
 776
 777        if (*bflags & BLIST_ISROM) {
 778                sdev->type = TYPE_ROM;
 779                sdev->removable = 1;
 780        } else {
 781                sdev->type = (inq_result[0] & 0x1f);
 782                sdev->removable = (inq_result[1] & 0x80) >> 7;
 783        }
 784
 785        switch (sdev->type) {
 786        case TYPE_RBC:
 787        case TYPE_TAPE:
 788        case TYPE_DISK:
 789        case TYPE_PRINTER:
 790        case TYPE_MOD:
 791        case TYPE_PROCESSOR:
 792        case TYPE_SCANNER:
 793        case TYPE_MEDIUM_CHANGER:
 794        case TYPE_ENCLOSURE:
 795        case TYPE_COMM:
 796        case TYPE_RAID:
 797        case TYPE_OSD:
 798                sdev->writeable = 1;
 799                break;
 800        case TYPE_ROM:
 801        case TYPE_WORM:
 802                sdev->writeable = 0;
 803                break;
 804        default:
 805                printk(KERN_INFO "scsi: unknown device type %d\n", sdev->type);
 806        }
 807
 808        if (sdev->type == TYPE_RBC || sdev->type == TYPE_ROM) {
 809                /* RBC and MMC devices can return SCSI-3 compliance and yet
 810                 * still not support REPORT LUNS, so make them act as
 811                 * BLIST_NOREPORTLUN unless BLIST_REPORTLUN2 is
 812                 * specifically set */
 813                if ((*bflags & BLIST_REPORTLUN2) == 0)
 814                        *bflags |= BLIST_NOREPORTLUN;
 815        }
 816
 817        /*
 818         * For a peripheral qualifier (PQ) value of 1 (001b), the SCSI
 819         * spec says: The device server is capable of supporting the
 820         * specified peripheral device type on this logical unit. However,
 821         * the physical device is not currently connected to this logical
 822         * unit.
 823         *
 824         * The above is vague, as it implies that we could treat 001 and
 825         * 011 the same. Stay compatible with previous code, and create a
 826         * scsi_device for a PQ of 1
 827         *
 828         * Don't set the device offline here; rather let the upper
 829         * level drivers eval the PQ to decide whether they should
 830         * attach. So remove ((inq_result[0] >> 5) & 7) == 1 check.
 831         */ 
 832
 833        sdev->inq_periph_qual = (inq_result[0] >> 5) & 7;
 834        sdev->lockable = sdev->removable;
 835        sdev->soft_reset = (inq_result[7] & 1) && ((inq_result[3] & 7) == 2);
 836
 837        if (sdev->scsi_level >= SCSI_3 ||
 838                        (sdev->inquiry_len > 56 && inq_result[56] & 0x04))
 839                sdev->ppr = 1;
 840        if (inq_result[7] & 0x60)
 841                sdev->wdtr = 1;
 842        if (inq_result[7] & 0x10)
 843                sdev->sdtr = 1;
 844
 845        sdev_printk(KERN_NOTICE, sdev, "%s %.8s %.16s %.4s PQ: %d "
 846                        "ANSI: %d%s\n", scsi_device_type(sdev->type),
 847                        sdev->vendor, sdev->model, sdev->rev,
 848                        sdev->inq_periph_qual, inq_result[2] & 0x07,
 849                        (inq_result[3] & 0x0f) == 1 ? " CCS" : "");
 850
 851        if ((sdev->scsi_level >= SCSI_2) && (inq_result[7] & 2) &&
 852            !(*bflags & BLIST_NOTQ))
 853                sdev->tagged_supported = 1;
 854
 855        /*
 856         * Some devices (Texel CD ROM drives) have handshaking problems
 857         * when used with the Seagate controllers. borken is initialized
 858         * to 1, and then set it to 0 here.
 859         */
 860        if ((*bflags & BLIST_BORKEN) == 0)
 861                sdev->borken = 0;
 862
 863        if (*bflags & BLIST_NO_ULD_ATTACH)
 864                sdev->no_uld_attach = 1;
 865
 866        /*
 867         * Apparently some really broken devices (contrary to the SCSI
 868         * standards) need to be selected without asserting ATN
 869         */
 870        if (*bflags & BLIST_SELECT_NO_ATN)
 871                sdev->select_no_atn = 1;
 872
 873        /*
 874         * Maximum 512 sector transfer length
 875         * broken RA4x00 Compaq Disk Array
 876         */
 877        if (*bflags & BLIST_MAX_512)
 878                blk_queue_max_hw_sectors(sdev->request_queue, 512);
 879
 880        /*
 881         * Some devices may not want to have a start command automatically
 882         * issued when a device is added.
 883         */
 884        if (*bflags & BLIST_NOSTARTONADD)
 885                sdev->no_start_on_add = 1;
 886
 887        if (*bflags & BLIST_SINGLELUN)
 888                scsi_target(sdev)->single_lun = 1;
 889
 890        sdev->use_10_for_rw = 1;
 891
 892        if (*bflags & BLIST_MS_SKIP_PAGE_08)
 893                sdev->skip_ms_page_8 = 1;
 894
 895        if (*bflags & BLIST_MS_SKIP_PAGE_3F)
 896                sdev->skip_ms_page_3f = 1;
 897
 898        if (*bflags & BLIST_USE_10_BYTE_MS)
 899                sdev->use_10_for_ms = 1;
 900
 901        /* set the device running here so that slave configure
 902         * may do I/O */
 903        ret = scsi_device_set_state(sdev, SDEV_RUNNING);
 904        if (ret) {
 905                ret = scsi_device_set_state(sdev, SDEV_BLOCK);
 906
 907                if (ret) {
 908                        sdev_printk(KERN_ERR, sdev,
 909                                    "in wrong state %s to complete scan\n",
 910                                    scsi_device_state_name(sdev->sdev_state));
 911                        return SCSI_SCAN_NO_RESPONSE;
 912                }
 913        }
 914
 915        if (*bflags & BLIST_MS_192_BYTES_FOR_3F)
 916                sdev->use_192_bytes_for_3f = 1;
 917
 918        if (*bflags & BLIST_NOT_LOCKABLE)
 919                sdev->lockable = 0;
 920
 921        if (*bflags & BLIST_RETRY_HWERROR)
 922                sdev->retry_hwerror = 1;
 923
 924        if (*bflags & BLIST_NO_DIF)
 925                sdev->no_dif = 1;
 926
 927        sdev->eh_timeout = SCSI_DEFAULT_EH_TIMEOUT;
 928
 929        if (*bflags & BLIST_SKIP_VPD_PAGES)
 930                sdev->skip_vpd_pages = 1;
 931
 932        transport_configure_device(&sdev->sdev_gendev);
 933
 934        if (sdev->host->hostt->slave_configure) {
 935                ret = sdev->host->hostt->slave_configure(sdev);
 936                if (ret) {
 937                        /*
 938                         * if LLDD reports slave not present, don't clutter
 939                         * console with alloc failure messages
 940                         */
 941                        if (ret != -ENXIO) {
 942                                sdev_printk(KERN_ERR, sdev,
 943                                        "failed to configure device\n");
 944                        }
 945                        return SCSI_SCAN_NO_RESPONSE;
 946                }
 947        }
 948
 949        sdev->max_queue_depth = sdev->queue_depth;
 950
 951        /*
 952         * Ok, the device is now all set up, we can
 953         * register it and tell the rest of the kernel
 954         * about it.
 955         */
 956        if (!async && scsi_sysfs_add_sdev(sdev) != 0)
 957                return SCSI_SCAN_NO_RESPONSE;
 958
 959        return SCSI_SCAN_LUN_PRESENT;
 960}
 961
 962#ifdef CONFIG_SCSI_LOGGING
 963/** 
 964 * scsi_inq_str - print INQUIRY data from min to max index, strip trailing whitespace
 965 * @buf:   Output buffer with at least end-first+1 bytes of space
 966 * @inq:   Inquiry buffer (input)
 967 * @first: Offset of string into inq
 968 * @end:   Index after last character in inq
 969 */
 970static unsigned char *scsi_inq_str(unsigned char *buf, unsigned char *inq,
 971                                   unsigned first, unsigned end)
 972{
 973        unsigned term = 0, idx;
 974
 975        for (idx = 0; idx + first < end && idx + first < inq[4] + 5; idx++) {
 976                if (inq[idx+first] > ' ') {
 977                        buf[idx] = inq[idx+first];
 978                        term = idx+1;
 979                } else {
 980                        buf[idx] = ' ';
 981                }
 982        }
 983        buf[term] = 0;
 984        return buf;
 985}
 986#endif
 987
 988/**
 989 * scsi_probe_and_add_lun - probe a LUN, if a LUN is found add it
 990 * @starget:    pointer to target device structure
 991 * @lun:        LUN of target device
 992 * @bflagsp:    store bflags here if not NULL
 993 * @sdevp:      probe the LUN corresponding to this scsi_device
 994 * @rescan:     if nonzero skip some code only needed on first scan
 995 * @hostdata:   passed to scsi_alloc_sdev()
 996 *
 997 * Description:
 998 *     Call scsi_probe_lun, if a LUN with an attached device is found,
 999 *     allocate and set it up by calling scsi_add_lun.
1000 *
1001 * Return:
1002 *     SCSI_SCAN_NO_RESPONSE: could not allocate or setup a scsi_device
1003 *     SCSI_SCAN_TARGET_PRESENT: target responded, but no device is
1004 *         attached at the LUN
1005 *     SCSI_SCAN_LUN_PRESENT: a new scsi_device was allocated and initialized
1006 **/
1007static int scsi_probe_and_add_lun(struct scsi_target *starget,
1008                                  uint lun, int *bflagsp,
1009                                  struct scsi_device **sdevp, int rescan,
1010                                  void *hostdata)
1011{
1012        struct scsi_device *sdev;
1013        unsigned char *result;
1014        int bflags, res = SCSI_SCAN_NO_RESPONSE, result_len = 256;
1015        struct Scsi_Host *shost = dev_to_shost(starget->dev.parent);
1016
1017        /*
1018         * The rescan flag is used as an optimization, the first scan of a
1019         * host adapter calls into here with rescan == 0.
1020         */
1021        sdev = scsi_device_lookup_by_target(starget, lun);
1022        if (sdev) {
1023                if (rescan || !scsi_device_created(sdev)) {
1024                        SCSI_LOG_SCAN_BUS(3, printk(KERN_INFO
1025                                "scsi scan: device exists on %s\n",
1026                                dev_name(&sdev->sdev_gendev)));
1027                        if (sdevp)
1028                                *sdevp = sdev;
1029                        else
1030                                scsi_device_put(sdev);
1031
1032                        if (bflagsp)
1033                                *bflagsp = scsi_get_device_flags(sdev,
1034                                                                 sdev->vendor,
1035                                                                 sdev->model);
1036                        return SCSI_SCAN_LUN_PRESENT;
1037                }
1038                scsi_device_put(sdev);
1039        } else
1040                sdev = scsi_alloc_sdev(starget, lun, hostdata);
1041        if (!sdev)
1042                goto out;
1043
1044        result = kmalloc(result_len, GFP_ATOMIC |
1045                        ((shost->unchecked_isa_dma) ? __GFP_DMA : 0));
1046        if (!result)
1047                goto out_free_sdev;
1048
1049        if (scsi_probe_lun(sdev, result, result_len, &bflags))
1050                goto out_free_result;
1051
1052        if (bflagsp)
1053                *bflagsp = bflags;
1054        /*
1055         * result contains valid SCSI INQUIRY data.
1056         */
1057        if (((result[0] >> 5) == 3) && !(bflags & BLIST_ATTACH_PQ3)) {
1058                /*
1059                 * For a Peripheral qualifier 3 (011b), the SCSI
1060                 * spec says: The device server is not capable of
1061                 * supporting a physical device on this logical
1062                 * unit.
1063                 *
1064                 * For disks, this implies that there is no
1065                 * logical disk configured at sdev->lun, but there
1066                 * is a target id responding.
1067                 */
1068                SCSI_LOG_SCAN_BUS(2, sdev_printk(KERN_INFO, sdev, "scsi scan:"
1069                                   " peripheral qualifier of 3, device not"
1070                                   " added\n"))
1071                if (lun == 0) {
1072                        SCSI_LOG_SCAN_BUS(1, {
1073                                unsigned char vend[9];
1074                                unsigned char mod[17];
1075
1076                                sdev_printk(KERN_INFO, sdev,
1077                                        "scsi scan: consider passing scsi_mod."
1078                                        "dev_flags=%s:%s:0x240 or 0x1000240\n",
1079                                        scsi_inq_str(vend, result, 8, 16),
1080                                        scsi_inq_str(mod, result, 16, 32));
1081                        });
1082
1083                }
1084
1085                res = SCSI_SCAN_TARGET_PRESENT;
1086                goto out_free_result;
1087        }
1088
1089        /*
1090         * Some targets may set slight variations of PQ and PDT to signal
1091         * that no LUN is present, so don't add sdev in these cases.
1092         * Two specific examples are:
1093         * 1) NetApp targets: return PQ=1, PDT=0x1f
1094         * 2) USB UFI: returns PDT=0x1f, with the PQ bits being "reserved"
1095         *    in the UFI 1.0 spec (we cannot rely on reserved bits).
1096         *
1097         * References:
1098         * 1) SCSI SPC-3, pp. 145-146
1099         * PQ=1: "A peripheral device having the specified peripheral
1100         * device type is not connected to this logical unit. However, the
1101         * device server is capable of supporting the specified peripheral
1102         * device type on this logical unit."
1103         * PDT=0x1f: "Unknown or no device type"
1104         * 2) USB UFI 1.0, p. 20
1105         * PDT=00h Direct-access device (floppy)
1106         * PDT=1Fh none (no FDD connected to the requested logical unit)
1107         */
1108        if (((result[0] >> 5) == 1 || starget->pdt_1f_for_no_lun) &&
1109            (result[0] & 0x1f) == 0x1f &&
1110            !scsi_is_wlun(lun)) {
1111                SCSI_LOG_SCAN_BUS(3, printk(KERN_INFO
1112                                        "scsi scan: peripheral device type"
1113                                        " of 31, no device added\n"));
1114                res = SCSI_SCAN_TARGET_PRESENT;
1115                goto out_free_result;
1116        }
1117
1118        res = scsi_add_lun(sdev, result, &bflags, shost->async_scan);
1119        if (res == SCSI_SCAN_LUN_PRESENT) {
1120                if (bflags & BLIST_KEY) {
1121                        sdev->lockable = 0;
1122                        scsi_unlock_floptical(sdev, result);
1123                }
1124        }
1125
1126 out_free_result:
1127        kfree(result);
1128 out_free_sdev:
1129        if (res == SCSI_SCAN_LUN_PRESENT) {
1130                if (sdevp) {
1131                        if (scsi_device_get(sdev) == 0) {
1132                                *sdevp = sdev;
1133                        } else {
1134                                __scsi_remove_device(sdev);
1135                                res = SCSI_SCAN_NO_RESPONSE;
1136                        }
1137                }
1138        } else
1139                __scsi_remove_device(sdev);
1140 out:
1141        return res;
1142}
1143
1144/**
1145 * scsi_sequential_lun_scan - sequentially scan a SCSI target
1146 * @starget:    pointer to target structure to scan
1147 * @bflags:     black/white list flag for LUN 0
1148 * @scsi_level: Which version of the standard does this device adhere to
1149 * @rescan:     passed to scsi_probe_add_lun()
1150 *
1151 * Description:
1152 *     Generally, scan from LUN 1 (LUN 0 is assumed to already have been
1153 *     scanned) to some maximum lun until a LUN is found with no device
1154 *     attached. Use the bflags to figure out any oddities.
1155 *
1156 *     Modifies sdevscan->lun.
1157 **/
1158static void scsi_sequential_lun_scan(struct scsi_target *starget,
1159                                     int bflags, int scsi_level, int rescan)
1160{
1161        unsigned int sparse_lun, lun, max_dev_lun;
1162        struct Scsi_Host *shost = dev_to_shost(starget->dev.parent);
1163
1164        SCSI_LOG_SCAN_BUS(3, printk(KERN_INFO "scsi scan: Sequential scan of"
1165                                    "%s\n", dev_name(&starget->dev)));
1166
1167        max_dev_lun = min(max_scsi_luns, shost->max_lun);
1168        /*
1169         * If this device is known to support sparse multiple units,
1170         * override the other settings, and scan all of them. Normally,
1171         * SCSI-3 devices should be scanned via the REPORT LUNS.
1172         */
1173        if (bflags & BLIST_SPARSELUN) {
1174                max_dev_lun = shost->max_lun;
1175                sparse_lun = 1;
1176        } else
1177                sparse_lun = 0;
1178
1179        /*
1180         * If less than SCSI_1_CSS, and no special lun scaning, stop
1181         * scanning; this matches 2.4 behaviour, but could just be a bug
1182         * (to continue scanning a SCSI_1_CSS device).
1183         *
1184         * This test is broken.  We might not have any device on lun0 for
1185         * a sparselun device, and if that's the case then how would we
1186         * know the real scsi_level, eh?  It might make sense to just not
1187         * scan any SCSI_1 device for non-0 luns, but that check would best
1188         * go into scsi_alloc_sdev() and just have it return null when asked
1189         * to alloc an sdev for lun > 0 on an already found SCSI_1 device.
1190         *
1191        if ((sdevscan->scsi_level < SCSI_1_CCS) &&
1192            ((bflags & (BLIST_FORCELUN | BLIST_SPARSELUN | BLIST_MAX5LUN))
1193             == 0))
1194                return;
1195         */
1196        /*
1197         * If this device is known to support multiple units, override
1198         * the other settings, and scan all of them.
1199         */
1200        if (bflags & BLIST_FORCELUN)
1201                max_dev_lun = shost->max_lun;
1202        /*
1203         * REGAL CDC-4X: avoid hang after LUN 4
1204         */
1205        if (bflags & BLIST_MAX5LUN)
1206                max_dev_lun = min(5U, max_dev_lun);
1207        /*
1208         * Do not scan SCSI-2 or lower device past LUN 7, unless
1209         * BLIST_LARGELUN.
1210         */
1211        if (scsi_level < SCSI_3 && !(bflags & BLIST_LARGELUN))
1212                max_dev_lun = min(8U, max_dev_lun);
1213
1214        /*
1215         * We have already scanned LUN 0, so start at LUN 1. Keep scanning
1216         * until we reach the max, or no LUN is found and we are not
1217         * sparse_lun.
1218         */
1219        for (lun = 1; lun < max_dev_lun; ++lun)
1220                if ((scsi_probe_and_add_lun(starget, lun, NULL, NULL, rescan,
1221                                            NULL) != SCSI_SCAN_LUN_PRESENT) &&
1222                    !sparse_lun)
1223                        return;
1224}
1225
1226/**
1227 * scsilun_to_int - convert a scsi_lun to an int
1228 * @scsilun:    struct scsi_lun to be converted.
1229 *
1230 * Description:
1231 *     Convert @scsilun from a struct scsi_lun to a four byte host byte-ordered
1232 *     integer, and return the result. The caller must check for
1233 *     truncation before using this function.
1234 *
1235 * Notes:
1236 *     The struct scsi_lun is assumed to be four levels, with each level
1237 *     effectively containing a SCSI byte-ordered (big endian) short; the
1238 *     addressing bits of each level are ignored (the highest two bits).
1239 *     For a description of the LUN format, post SCSI-3 see the SCSI
1240 *     Architecture Model, for SCSI-3 see the SCSI Controller Commands.
1241 *
1242 *     Given a struct scsi_lun of: 0a 04 0b 03 00 00 00 00, this function returns
1243 *     the integer: 0x0b030a04
1244 **/
1245int scsilun_to_int(struct scsi_lun *scsilun)
1246{
1247        int i;
1248        unsigned int lun;
1249
1250        lun = 0;
1251        for (i = 0; i < sizeof(lun); i += 2)
1252                lun = lun | (((scsilun->scsi_lun[i] << 8) |
1253                              scsilun->scsi_lun[i + 1]) << (i * 8));
1254        return lun;
1255}
1256EXPORT_SYMBOL(scsilun_to_int);
1257
1258/**
1259 * int_to_scsilun - reverts an int into a scsi_lun
1260 * @lun:        integer to be reverted
1261 * @scsilun:    struct scsi_lun to be set.
1262 *
1263 * Description:
1264 *     Reverts the functionality of the scsilun_to_int, which packed
1265 *     an 8-byte lun value into an int. This routine unpacks the int
1266 *     back into the lun value.
1267 *     Note: the scsilun_to_int() routine does not truly handle all
1268 *     8bytes of the lun value. This functions restores only as much
1269 *     as was set by the routine.
1270 *
1271 * Notes:
1272 *     Given an integer : 0x0b030a04,  this function returns a
1273 *     scsi_lun of : struct scsi_lun of: 0a 04 0b 03 00 00 00 00
1274 *
1275 **/
1276void int_to_scsilun(unsigned int lun, struct scsi_lun *scsilun)
1277{
1278        int i;
1279
1280        memset(scsilun->scsi_lun, 0, sizeof(scsilun->scsi_lun));
1281
1282        for (i = 0; i < sizeof(lun); i += 2) {
1283                scsilun->scsi_lun[i] = (lun >> 8) & 0xFF;
1284                scsilun->scsi_lun[i+1] = lun & 0xFF;
1285                lun = lun >> 16;
1286        }
1287}
1288EXPORT_SYMBOL(int_to_scsilun);
1289
1290/**
1291 * scsi_report_lun_scan - Scan using SCSI REPORT LUN results
1292 * @starget: which target
1293 * @bflags: Zero or a mix of BLIST_NOLUN, BLIST_REPORTLUN2, or BLIST_NOREPORTLUN
1294 * @rescan: nonzero if we can skip code only needed on first scan
1295 *
1296 * Description:
1297 *   Fast scanning for modern (SCSI-3) devices by sending a REPORT LUN command.
1298 *   Scan the resulting list of LUNs by calling scsi_probe_and_add_lun.
1299 *
1300 *   If BLINK_REPORTLUN2 is set, scan a target that supports more than 8
1301 *   LUNs even if it's older than SCSI-3.
1302 *   If BLIST_NOREPORTLUN is set, return 1 always.
1303 *   If BLIST_NOLUN is set, return 0 always.
1304 *   If starget->no_report_luns is set, return 1 always.
1305 *
1306 * Return:
1307 *     0: scan completed (or no memory, so further scanning is futile)
1308 *     1: could not scan with REPORT LUN
1309 **/
1310static int scsi_report_lun_scan(struct scsi_target *starget, int bflags,
1311                                int rescan)
1312{
1313        char devname[64];
1314        unsigned char scsi_cmd[MAX_COMMAND_SIZE];
1315        unsigned int length;
1316        unsigned int lun;
1317        unsigned int num_luns;
1318        unsigned int retries;
1319        int result;
1320        struct scsi_lun *lunp, *lun_data;
1321        u8 *data;
1322        struct scsi_sense_hdr sshdr;
1323        struct scsi_device *sdev;
1324        struct Scsi_Host *shost = dev_to_shost(&starget->dev);
1325        int ret = 0;
1326
1327        /*
1328         * Only support SCSI-3 and up devices if BLIST_NOREPORTLUN is not set.
1329         * Also allow SCSI-2 if BLIST_REPORTLUN2 is set and host adapter does
1330         * support more than 8 LUNs.
1331         * Don't attempt if the target doesn't support REPORT LUNS.
1332         */
1333        if (bflags & BLIST_NOREPORTLUN)
1334                return 1;
1335        if (starget->scsi_level < SCSI_2 &&
1336            starget->scsi_level != SCSI_UNKNOWN)
1337                return 1;
1338        if (starget->scsi_level < SCSI_3 &&
1339            (!(bflags & BLIST_REPORTLUN2) || shost->max_lun <= 8))
1340                return 1;
1341        if (bflags & BLIST_NOLUN)
1342                return 0;
1343        if (starget->no_report_luns)
1344                return 1;
1345
1346        if (!(sdev = scsi_device_lookup_by_target(starget, 0))) {
1347                sdev = scsi_alloc_sdev(starget, 0, NULL);
1348                if (!sdev)
1349                        return 0;
1350                if (scsi_device_get(sdev)) {
1351                        __scsi_remove_device(sdev);
1352                        return 0;
1353                }
1354        }
1355
1356        sprintf(devname, "host %d channel %d id %d",
1357                shost->host_no, sdev->channel, sdev->id);
1358
1359        /*
1360         * Allocate enough to hold the header (the same size as one scsi_lun)
1361         * plus the max number of luns we are requesting.
1362         *
1363         * Reallocating and trying again (with the exact amount we need)
1364         * would be nice, but then we need to somehow limit the size
1365         * allocated based on the available memory and the limits of
1366         * kmalloc - we don't want a kmalloc() failure of a huge value to
1367         * prevent us from finding any LUNs on this target.
1368         */
1369        length = (max_scsi_report_luns + 1) * sizeof(struct scsi_lun);
1370        lun_data = kmalloc(length, GFP_ATOMIC |
1371                           (sdev->host->unchecked_isa_dma ? __GFP_DMA : 0));
1372        if (!lun_data) {
1373                printk(ALLOC_FAILURE_MSG, __func__);
1374                goto out;
1375        }
1376
1377        scsi_cmd[0] = REPORT_LUNS;
1378
1379        /*
1380         * bytes 1 - 5: reserved, set to zero.
1381         */
1382        memset(&scsi_cmd[1], 0, 5);
1383
1384        /*
1385         * bytes 6 - 9: length of the command.
1386         */
1387        scsi_cmd[6] = (unsigned char) (length >> 24) & 0xff;
1388        scsi_cmd[7] = (unsigned char) (length >> 16) & 0xff;
1389        scsi_cmd[8] = (unsigned char) (length >> 8) & 0xff;
1390        scsi_cmd[9] = (unsigned char) length & 0xff;
1391
1392        scsi_cmd[10] = 0;       /* reserved */
1393        scsi_cmd[11] = 0;       /* control */
1394
1395        /*
1396         * We can get a UNIT ATTENTION, for example a power on/reset, so
1397         * retry a few times (like sd.c does for TEST UNIT READY).
1398         * Experience shows some combinations of adapter/devices get at
1399         * least two power on/resets.
1400         *
1401         * Illegal requests (for devices that do not support REPORT LUNS)
1402         * should come through as a check condition, and will not generate
1403         * a retry.
1404         */
1405        for (retries = 0; retries < 3; retries++) {
1406                SCSI_LOG_SCAN_BUS(3, printk (KERN_INFO "scsi scan: Sending"
1407                                " REPORT LUNS to %s (try %d)\n", devname,
1408                                retries));
1409
1410                result = scsi_execute_req(sdev, scsi_cmd, DMA_FROM_DEVICE,
1411                                          lun_data, length, &sshdr,
1412                                          SCSI_TIMEOUT + 4 * HZ, 3, NULL);
1413
1414                SCSI_LOG_SCAN_BUS(3, printk (KERN_INFO "scsi scan: REPORT LUNS"
1415                                " %s (try %d) result 0x%x\n", result
1416                                ?  "failed" : "successful", retries, result));
1417                if (result == 0)
1418                        break;
1419                else if (scsi_sense_valid(&sshdr)) {
1420                        if (sshdr.sense_key != UNIT_ATTENTION)
1421                                break;
1422                }
1423        }
1424
1425        if (result) {
1426                /*
1427                 * The device probably does not support a REPORT LUN command
1428                 */
1429                ret = 1;
1430                goto out_err;
1431        }
1432
1433        /*
1434         * Get the length from the first four bytes of lun_data.
1435         */
1436        data = (u8 *) lun_data->scsi_lun;
1437        length = ((data[0] << 24) | (data[1] << 16) |
1438                  (data[2] << 8) | (data[3] << 0));
1439
1440        num_luns = (length / sizeof(struct scsi_lun));
1441        if (num_luns > max_scsi_report_luns) {
1442                printk(KERN_WARNING "scsi: On %s only %d (max_scsi_report_luns)"
1443                       " of %d luns reported, try increasing"
1444                       " max_scsi_report_luns.\n", devname,
1445                       max_scsi_report_luns, num_luns);
1446                num_luns = max_scsi_report_luns;
1447        }
1448
1449        SCSI_LOG_SCAN_BUS(3, sdev_printk (KERN_INFO, sdev,
1450                "scsi scan: REPORT LUN scan\n"));
1451
1452        /*
1453         * Scan the luns in lun_data. The entry at offset 0 is really
1454         * the header, so start at 1 and go up to and including num_luns.
1455         */
1456        for (lunp = &lun_data[1]; lunp <= &lun_data[num_luns]; lunp++) {
1457                lun = scsilun_to_int(lunp);
1458
1459                /*
1460                 * Check if the unused part of lunp is non-zero, and so
1461                 * does not fit in lun.
1462                 */
1463                if (memcmp(&lunp->scsi_lun[sizeof(lun)], "\0\0\0\0", 4)) {
1464                        int i;
1465
1466                        /*
1467                         * Output an error displaying the LUN in byte order,
1468                         * this differs from what linux would print for the
1469                         * integer LUN value.
1470                         */
1471                        printk(KERN_WARNING "scsi: %s lun 0x", devname);
1472                        data = (char *)lunp->scsi_lun;
1473                        for (i = 0; i < sizeof(struct scsi_lun); i++)
1474                                printk("%02x", data[i]);
1475                        printk(" has a LUN larger than currently supported.\n");
1476                } else if (lun > sdev->host->max_lun) {
1477                        printk(KERN_WARNING "scsi: %s lun%d has a LUN larger"
1478                               " than allowed by the host adapter\n",
1479                               devname, lun);
1480                } else {
1481                        int res;
1482
1483                        res = scsi_probe_and_add_lun(starget,
1484                                lun, NULL, NULL, rescan, NULL);
1485                        if (res == SCSI_SCAN_NO_RESPONSE) {
1486                                /*
1487                                 * Got some results, but now none, abort.
1488                                 */
1489                                sdev_printk(KERN_ERR, sdev,
1490                                        "Unexpected response"
1491                                        " from lun %d while scanning, scan"
1492                                        " aborted\n", lun);
1493                                break;
1494                        }
1495                }
1496        }
1497
1498 out_err:
1499        kfree(lun_data);
1500 out:
1501        scsi_device_put(sdev);
1502        if (scsi_device_created(sdev))
1503                /*
1504                 * the sdev we used didn't appear in the report luns scan
1505                 */
1506                __scsi_remove_device(sdev);
1507        return ret;
1508}
1509
1510struct scsi_device *__scsi_add_device(struct Scsi_Host *shost, uint channel,
1511                                      uint id, uint lun, void *hostdata)
1512{
1513        struct scsi_device *sdev = ERR_PTR(-ENODEV);
1514        struct device *parent = &shost->shost_gendev;
1515        struct scsi_target *starget;
1516
1517        if (strncmp(scsi_scan_type, "none", 4) == 0)
1518                return ERR_PTR(-ENODEV);
1519
1520        starget = scsi_alloc_target(parent, channel, id);
1521        if (!starget)
1522                return ERR_PTR(-ENOMEM);
1523        scsi_autopm_get_target(starget);
1524
1525        mutex_lock(&shost->scan_mutex);
1526        if (!shost->async_scan)
1527                scsi_complete_async_scans();
1528
1529        if (scsi_host_scan_allowed(shost) && scsi_autopm_get_host(shost) == 0) {
1530                scsi_probe_and_add_lun(starget, lun, NULL, &sdev, 1, hostdata);
1531                scsi_autopm_put_host(shost);
1532        }
1533        mutex_unlock(&shost->scan_mutex);
1534        scsi_autopm_put_target(starget);
1535        scsi_target_reap(starget);
1536        put_device(&starget->dev);
1537
1538        return sdev;
1539}
1540EXPORT_SYMBOL(__scsi_add_device);
1541
1542int scsi_add_device(struct Scsi_Host *host, uint channel,
1543                    uint target, uint lun)
1544{
1545        struct scsi_device *sdev = 
1546                __scsi_add_device(host, channel, target, lun, NULL);
1547        if (IS_ERR(sdev))
1548                return PTR_ERR(sdev);
1549
1550        scsi_device_put(sdev);
1551        return 0;
1552}
1553EXPORT_SYMBOL(scsi_add_device);
1554
1555void scsi_rescan_device(struct device *dev)
1556{
1557        struct scsi_driver *drv;
1558        
1559        if (!dev->driver)
1560                return;
1561
1562        drv = to_scsi_driver(dev->driver);
1563        if (try_module_get(drv->owner)) {
1564                if (drv->rescan)
1565                        drv->rescan(dev);
1566                module_put(drv->owner);
1567        }
1568}
1569EXPORT_SYMBOL(scsi_rescan_device);
1570
1571static void __scsi_scan_target(struct device *parent, unsigned int channel,
1572                unsigned int id, unsigned int lun, int rescan)
1573{
1574        struct Scsi_Host *shost = dev_to_shost(parent);
1575        int bflags = 0;
1576        int res;
1577        struct scsi_target *starget;
1578
1579        if (shost->this_id == id)
1580                /*
1581                 * Don't scan the host adapter
1582                 */
1583                return;
1584
1585        starget = scsi_alloc_target(parent, channel, id);
1586        if (!starget)
1587                return;
1588        scsi_autopm_get_target(starget);
1589
1590        if (lun != SCAN_WILD_CARD) {
1591                /*
1592                 * Scan for a specific host/chan/id/lun.
1593                 */
1594                scsi_probe_and_add_lun(starget, lun, NULL, NULL, rescan, NULL);
1595                goto out_reap;
1596        }
1597
1598        /*
1599         * Scan LUN 0, if there is some response, scan further. Ideally, we
1600         * would not configure LUN 0 until all LUNs are scanned.
1601         */
1602        res = scsi_probe_and_add_lun(starget, 0, &bflags, NULL, rescan, NULL);
1603        if (res == SCSI_SCAN_LUN_PRESENT || res == SCSI_SCAN_TARGET_PRESENT) {
1604                if (scsi_report_lun_scan(starget, bflags, rescan) != 0)
1605                        /*
1606                         * The REPORT LUN did not scan the target,
1607                         * do a sequential scan.
1608                         */
1609                        scsi_sequential_lun_scan(starget, bflags,
1610                                                 starget->scsi_level, rescan);
1611        }
1612
1613 out_reap:
1614        scsi_autopm_put_target(starget);
1615        /* now determine if the target has any children at all
1616         * and if not, nuke it */
1617        scsi_target_reap(starget);
1618
1619        put_device(&starget->dev);
1620}
1621
1622/**
1623 * scsi_scan_target - scan a target id, possibly including all LUNs on the target.
1624 * @parent:     host to scan
1625 * @channel:    channel to scan
1626 * @id:         target id to scan
1627 * @lun:        Specific LUN to scan or SCAN_WILD_CARD
1628 * @rescan:     passed to LUN scanning routines
1629 *
1630 * Description:
1631 *     Scan the target id on @parent, @channel, and @id. Scan at least LUN 0,
1632 *     and possibly all LUNs on the target id.
1633 *
1634 *     First try a REPORT LUN scan, if that does not scan the target, do a
1635 *     sequential scan of LUNs on the target id.
1636 **/
1637void scsi_scan_target(struct device *parent, unsigned int channel,
1638                      unsigned int id, unsigned int lun, int rescan)
1639{
1640        struct Scsi_Host *shost = dev_to_shost(parent);
1641
1642        if (strncmp(scsi_scan_type, "none", 4) == 0)
1643                return;
1644
1645        mutex_lock(&shost->scan_mutex);
1646        if (!shost->async_scan)
1647                scsi_complete_async_scans();
1648
1649        if (scsi_host_scan_allowed(shost) && scsi_autopm_get_host(shost) == 0) {
1650                __scsi_scan_target(parent, channel, id, lun, rescan);
1651                scsi_autopm_put_host(shost);
1652        }
1653        mutex_unlock(&shost->scan_mutex);
1654}
1655EXPORT_SYMBOL(scsi_scan_target);
1656
1657static void scsi_scan_channel(struct Scsi_Host *shost, unsigned int channel,
1658                              unsigned int id, unsigned int lun, int rescan)
1659{
1660        uint order_id;
1661
1662        if (id == SCAN_WILD_CARD)
1663                for (id = 0; id < shost->max_id; ++id) {
1664                        /*
1665                         * XXX adapter drivers when possible (FCP, iSCSI)
1666                         * could modify max_id to match the current max,
1667                         * not the absolute max.
1668                         *
1669                         * XXX add a shost id iterator, so for example,
1670                         * the FC ID can be the same as a target id
1671                         * without a huge overhead of sparse id's.
1672                         */
1673                        if (shost->reverse_ordering)
1674                                /*
1675                                 * Scan from high to low id.
1676                                 */
1677                                order_id = shost->max_id - id - 1;
1678                        else
1679                                order_id = id;
1680                        __scsi_scan_target(&shost->shost_gendev, channel,
1681                                        order_id, lun, rescan);
1682                }
1683        else
1684                __scsi_scan_target(&shost->shost_gendev, channel,
1685                                id, lun, rescan);
1686}
1687
1688int scsi_scan_host_selected(struct Scsi_Host *shost, unsigned int channel,
1689                            unsigned int id, unsigned int lun, int rescan)
1690{
1691        SCSI_LOG_SCAN_BUS(3, shost_printk (KERN_INFO, shost,
1692                "%s: <%u:%u:%u>\n",
1693                __func__, channel, id, lun));
1694
1695        if (((channel != SCAN_WILD_CARD) && (channel > shost->max_channel)) ||
1696            ((id != SCAN_WILD_CARD) && (id >= shost->max_id)) ||
1697            ((lun != SCAN_WILD_CARD) && (lun > shost->max_lun)))
1698                return -EINVAL;
1699
1700        mutex_lock(&shost->scan_mutex);
1701        if (!shost->async_scan)
1702                scsi_complete_async_scans();
1703
1704        if (scsi_host_scan_allowed(shost) && scsi_autopm_get_host(shost) == 0) {
1705                if (channel == SCAN_WILD_CARD)
1706                        for (channel = 0; channel <= shost->max_channel;
1707                             channel++)
1708                                scsi_scan_channel(shost, channel, id, lun,
1709                                                  rescan);
1710                else
1711                        scsi_scan_channel(shost, channel, id, lun, rescan);
1712                scsi_autopm_put_host(shost);
1713        }
1714        mutex_unlock(&shost->scan_mutex);
1715
1716        return 0;
1717}
1718
1719static void scsi_sysfs_add_devices(struct Scsi_Host *shost)
1720{
1721        struct scsi_device *sdev;
1722        shost_for_each_device(sdev, shost) {
1723                /* target removed before the device could be added */
1724                if (sdev->sdev_state == SDEV_DEL)
1725                        continue;
1726                if (!scsi_host_scan_allowed(shost) ||
1727                    scsi_sysfs_add_sdev(sdev) != 0)
1728                        __scsi_remove_device(sdev);
1729        }
1730}
1731
1732/**
1733 * scsi_prep_async_scan - prepare for an async scan
1734 * @shost: the host which will be scanned
1735 * Returns: a cookie to be passed to scsi_finish_async_scan()
1736 *
1737 * Tells the midlayer this host is going to do an asynchronous scan.
1738 * It reserves the host's position in the scanning list and ensures
1739 * that other asynchronous scans started after this one won't affect the
1740 * ordering of the discovered devices.
1741 */
1742static struct async_scan_data *scsi_prep_async_scan(struct Scsi_Host *shost)
1743{
1744        struct async_scan_data *data;
1745        unsigned long flags;
1746
1747        if (strncmp(scsi_scan_type, "sync", 4) == 0)
1748                return NULL;
1749
1750        if (shost->async_scan) {
1751                printk("%s called twice for host %d", __func__,
1752                                shost->host_no);
1753                dump_stack();
1754                return NULL;
1755        }
1756
1757        data = kmalloc(sizeof(*data), GFP_KERNEL);
1758        if (!data)
1759                goto err;
1760        data->shost = scsi_host_get(shost);
1761        if (!data->shost)
1762                goto err;
1763        init_completion(&data->prev_finished);
1764
1765        mutex_lock(&shost->scan_mutex);
1766        spin_lock_irqsave(shost->host_lock, flags);
1767        shost->async_scan = 1;
1768        spin_unlock_irqrestore(shost->host_lock, flags);
1769        mutex_unlock(&shost->scan_mutex);
1770
1771        spin_lock(&async_scan_lock);
1772        if (list_empty(&scanning_hosts))
1773                complete(&data->prev_finished);
1774        list_add_tail(&data->list, &scanning_hosts);
1775        spin_unlock(&async_scan_lock);
1776
1777        return data;
1778
1779 err:
1780        kfree(data);
1781        return NULL;
1782}
1783
1784/**
1785 * scsi_finish_async_scan - asynchronous scan has finished
1786 * @data: cookie returned from earlier call to scsi_prep_async_scan()
1787 *
1788 * All the devices currently attached to this host have been found.
1789 * This function announces all the devices it has found to the rest
1790 * of the system.
1791 */
1792static void scsi_finish_async_scan(struct async_scan_data *data)
1793{
1794        struct Scsi_Host *shost;
1795        unsigned long flags;
1796
1797        if (!data)
1798                return;
1799
1800        shost = data->shost;
1801
1802        mutex_lock(&shost->scan_mutex);
1803
1804        if (!shost->async_scan) {
1805                printk("%s called twice for host %d", __func__,
1806                                shost->host_no);
1807                dump_stack();
1808                mutex_unlock(&shost->scan_mutex);
1809                return;
1810        }
1811
1812        wait_for_completion(&data->prev_finished);
1813
1814        scsi_sysfs_add_devices(shost);
1815
1816        spin_lock_irqsave(shost->host_lock, flags);
1817        shost->async_scan = 0;
1818        spin_unlock_irqrestore(shost->host_lock, flags);
1819
1820        mutex_unlock(&shost->scan_mutex);
1821
1822        spin_lock(&async_scan_lock);
1823        list_del(&data->list);
1824        if (!list_empty(&scanning_hosts)) {
1825                struct async_scan_data *next = list_entry(scanning_hosts.next,
1826                                struct async_scan_data, list);
1827                complete(&next->prev_finished);
1828        }
1829        spin_unlock(&async_scan_lock);
1830
1831        scsi_autopm_put_host(shost);
1832        scsi_host_put(shost);
1833        kfree(data);
1834}
1835
1836static void do_scsi_scan_host(struct Scsi_Host *shost)
1837{
1838        if (shost->hostt->scan_finished) {
1839                unsigned long start = jiffies;
1840                if (shost->hostt->scan_start)
1841                        shost->hostt->scan_start(shost);
1842
1843                while (!shost->hostt->scan_finished(shost, jiffies - start))
1844                        msleep(10);
1845        } else {
1846                scsi_scan_host_selected(shost, SCAN_WILD_CARD, SCAN_WILD_CARD,
1847                                SCAN_WILD_CARD, 0);
1848        }
1849}
1850
1851static void do_scan_async(void *_data, async_cookie_t c)
1852{
1853        struct async_scan_data *data = _data;
1854        struct Scsi_Host *shost = data->shost;
1855
1856        do_scsi_scan_host(shost);
1857        scsi_finish_async_scan(data);
1858}
1859
1860/**
1861 * scsi_scan_host - scan the given adapter
1862 * @shost:      adapter to scan
1863 **/
1864void scsi_scan_host(struct Scsi_Host *shost)
1865{
1866        struct async_scan_data *data;
1867
1868        if (strncmp(scsi_scan_type, "none", 4) == 0)
1869                return;
1870        if (scsi_autopm_get_host(shost) < 0)
1871                return;
1872
1873        data = scsi_prep_async_scan(shost);
1874        if (!data) {
1875                do_scsi_scan_host(shost);
1876                scsi_autopm_put_host(shost);
1877                return;
1878        }
1879
1880        /* register with the async subsystem so wait_for_device_probe()
1881         * will flush this work
1882         */
1883        async_schedule(do_scan_async, data);
1884
1885        /* scsi_autopm_put_host(shost) is called in scsi_finish_async_scan() */
1886}
1887EXPORT_SYMBOL(scsi_scan_host);
1888
1889void scsi_forget_host(struct Scsi_Host *shost)
1890{
1891        struct scsi_device *sdev;
1892        unsigned long flags;
1893
1894 restart:
1895        spin_lock_irqsave(shost->host_lock, flags);
1896        list_for_each_entry(sdev, &shost->__devices, siblings) {
1897                if (sdev->sdev_state == SDEV_DEL)
1898                        continue;
1899                spin_unlock_irqrestore(shost->host_lock, flags);
1900                __scsi_remove_device(sdev);
1901                goto restart;
1902        }
1903        spin_unlock_irqrestore(shost->host_lock, flags);
1904}
1905
1906/**
1907 * scsi_get_host_dev - Create a scsi_device that points to the host adapter itself
1908 * @shost: Host that needs a scsi_device
1909 *
1910 * Lock status: None assumed.
1911 *
1912 * Returns:     The scsi_device or NULL
1913 *
1914 * Notes:
1915 *      Attach a single scsi_device to the Scsi_Host - this should
1916 *      be made to look like a "pseudo-device" that points to the
1917 *      HA itself.
1918 *
1919 *      Note - this device is not accessible from any high-level
1920 *      drivers (including generics), which is probably not
1921 *      optimal.  We can add hooks later to attach.
1922 */
1923struct scsi_device *scsi_get_host_dev(struct Scsi_Host *shost)
1924{
1925        struct scsi_device *sdev = NULL;
1926        struct scsi_target *starget;
1927
1928        mutex_lock(&shost->scan_mutex);
1929        if (!scsi_host_scan_allowed(shost))
1930                goto out;
1931        starget = scsi_alloc_target(&shost->shost_gendev, 0, shost->this_id);
1932        if (!starget)
1933                goto out;
1934
1935        sdev = scsi_alloc_sdev(starget, 0, NULL);
1936        if (sdev)
1937                sdev->borken = 0;
1938        else
1939                scsi_target_reap(starget);
1940        put_device(&starget->dev);
1941 out:
1942        mutex_unlock(&shost->scan_mutex);
1943        return sdev;
1944}
1945EXPORT_SYMBOL(scsi_get_host_dev);
1946
1947/**
1948 * scsi_free_host_dev - Free a scsi_device that points to the host adapter itself
1949 * @sdev: Host device to be freed
1950 *
1951 * Lock status: None assumed.
1952 *
1953 * Returns:     Nothing
1954 */
1955void scsi_free_host_dev(struct scsi_device *sdev)
1956{
1957        BUG_ON(sdev->id != sdev->host->this_id);
1958
1959        __scsi_remove_device(sdev);
1960}
1961EXPORT_SYMBOL(scsi_free_host_dev);
1962
1963
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