drivers/scsi/hosts.c

   1 // SPDX-License-Identifier: GPL-2.0-only
   2 /*
   3  *  hosts.c Copyright (C) 1992 Drew Eckhardt
   4  *          Copyright (C) 1993, 1994, 1995 Eric Youngdale
   5  *          Copyright (C) 2002-2003 Christoph Hellwig
   6  *
   7  *  mid to lowlevel SCSI driver interface
   8  *      Initial versions: Drew Eckhardt
   9  *      Subsequent revisions: Eric Youngdale
  10  *
  11  *  <drew@colorado.edu>
  12  *
  13  *  Jiffies wrap fixes (host->resetting), 3 Dec 1998 Andrea Arcangeli
  14  *  Added QLOGIC QLA1280 SCSI controller kernel host support.
  15  *     August 4, 1999 Fred Lewis, Intel DuPont
  16  *
  17  *  Updated to reflect the new initialization scheme for the higher
  18  *  level of scsi drivers (sd/sr/st)
  19  *  September 17, 2000 Torben Mathiasen <tmm@image.dk>
  20  *
  21  *  Restructured scsi_host lists and associated functions.
  22  *  September 04, 2002 Mike Anderson (andmike@us.ibm.com)
  23  */
  24
  25 #include <linux/module.h>
  26 #include <linux/blkdev.h>
  27 #include <linux/kernel.h>
  28 #include <linux/slab.h>
  29 #include <linux/kthread.h>
  30 #include <linux/string.h>
  31 #include <linux/mm.h>
  32 #include <linux/init.h>
  33 #include <linux/completion.h>
  34 #include <linux/transport_class.h>
  35 #include <linux/platform_device.h>
  36 #include <linux/pm_runtime.h>
  37 #include <linux/idr.h>
  38 #include <scsi/scsi_device.h>
  39 #include <scsi/scsi_host.h>
  40 #include <scsi/scsi_transport.h>
  41 #include <scsi/scsi_cmnd.h>
  42
  43 #include "scsi_priv.h"
  44 #include "scsi_logging.h"
  45
  46
  47 static int shost_eh_deadline = -1;
  48
  49 module_param_named(eh_deadline, shost_eh_deadline, int, S_IRUGO|S_IWUSR);
  50 MODULE_PARM_DESC(eh_deadline,
  51                  "SCSI EH timeout in seconds (should be between 0 and 2^31-1)");
  52
  53 static DEFINE_IDA(host_index_ida);
  54
  55
  56 static void scsi_host_cls_release(struct device *dev)
  57 {
  58         put_device(&class_to_shost(dev)->shost_gendev);
  59 }
  60
  61 static struct class shost_class = {
  62         .name           = "scsi_host",
  63         .dev_release    = scsi_host_cls_release,
  64         .dev_groups     = scsi_shost_groups,
  65 };
  66
  67 /**
  68  *      scsi_host_set_state - Take the given host through the host state model.
  69  *      @shost: scsi host to change the state of.
  70  *      @state: state to change to.
  71  *
  72  *      Returns zero if unsuccessful or an error if the requested
  73  *      transition is illegal.
  74  **/
  75 int scsi_host_set_state(struct Scsi_Host *shost, enum scsi_host_state state)
  76 {
  77         enum scsi_host_state oldstate = shost->shost_state;
  78
  79         if (state == oldstate)
  80                 return 0;
  81
  82         switch (state) {
  83         case SHOST_CREATED:
  84                 /* There are no legal states that come back to
  85                  * created.  This is the manually initialised start
  86                  * state */
  87                 goto illegal;
  88
  89         case SHOST_RUNNING:
  90                 switch (oldstate) {
  91                 case SHOST_CREATED:
  92                 case SHOST_RECOVERY:
  93                         break;
  94                 default:
  95                         goto illegal;
  96                 }
  97                 break;
  98
  99         case SHOST_RECOVERY:
 100                 switch (oldstate) {
 101                 case SHOST_RUNNING:
 102                         break;
 103                 default:
 104                         goto illegal;
 105                 }
 106                 break;
 107
 108         case SHOST_CANCEL:
 109                 switch (oldstate) {
 110                 case SHOST_CREATED:
 111                 case SHOST_RUNNING:
 112                 case SHOST_CANCEL_RECOVERY:
 113                         break;
 114                 default:
 115                         goto illegal;
 116                 }
 117                 break;
 118
 119         case SHOST_DEL:
 120                 switch (oldstate) {
 121                 case SHOST_CANCEL:
 122                 case SHOST_DEL_RECOVERY:
 123                         break;
 124                 default:
 125                         goto illegal;
 126                 }
 127                 break;
 128
 129         case SHOST_CANCEL_RECOVERY:
 130                 switch (oldstate) {
 131                 case SHOST_CANCEL:
 132                 case SHOST_RECOVERY:
 133                         break;
 134                 default:
 135                         goto illegal;
 136                 }
 137                 break;
 138
 139         case SHOST_DEL_RECOVERY:
 140                 switch (oldstate) {
 141                 case SHOST_CANCEL_RECOVERY:
 142                         break;
 143                 default:
 144                         goto illegal;
 145                 }
 146                 break;
 147         }
 148         shost->shost_state = state;
 149         return 0;
 150
 151  illegal:
 152         SCSI_LOG_ERROR_RECOVERY(1,
 153                                 shost_printk(KERN_ERR, shost,
 154                                              "Illegal host state transition"
 155                                              "%s->%s\n",
 156                                              scsi_host_state_name(oldstate),
 157                                              scsi_host_state_name(state)));
 158         return -EINVAL;
 159 }
 160
 161 /**
 162  * scsi_remove_host - remove a scsi host
 163  * @shost:      a pointer to a scsi host to remove
 164  **/
 165 void scsi_remove_host(struct Scsi_Host *shost)
 166 {
 167         unsigned long flags;
 168
 169         mutex_lock(&shost->scan_mutex);
 170         spin_lock_irqsave(shost->host_lock, flags);
 171         if (scsi_host_set_state(shost, SHOST_CANCEL))
 172                 if (scsi_host_set_state(shost, SHOST_CANCEL_RECOVERY)) {
 173                         spin_unlock_irqrestore(shost->host_lock, flags);
 174                         mutex_unlock(&shost->scan_mutex);
 175                         return;
 176                 }
 177         spin_unlock_irqrestore(shost->host_lock, flags);
 178
 179         scsi_autopm_get_host(shost);
 180         flush_workqueue(shost->tmf_work_q);
 181         scsi_forget_host(shost);
 182         mutex_unlock(&shost->scan_mutex);
 183         scsi_proc_host_rm(shost);
 184
 185         spin_lock_irqsave(shost->host_lock, flags);
 186         if (scsi_host_set_state(shost, SHOST_DEL))
 187                 BUG_ON(scsi_host_set_state(shost, SHOST_DEL_RECOVERY));
 188         spin_unlock_irqrestore(shost->host_lock, flags);
 189
 190         transport_unregister_device(&shost->shost_gendev);
 191         device_unregister(&shost->shost_dev);
 192         device_del(&shost->shost_gendev);
 193
 194         /*
 195          * After scsi_remove_host() has returned the scsi LLD module can be
 196          * unloaded and/or the host resources can be released. Hence wait until
 197          * the dependent SCSI targets and devices are gone before returning.
 198          */
 199         wait_event(shost->targets_wq, atomic_read(&shost->target_count) == 0);
 200 }
 201 EXPORT_SYMBOL(scsi_remove_host);
 202
 203 /**
 204  * scsi_add_host_with_dma - add a scsi host with dma device
 205  * @shost:      scsi host pointer to add
 206  * @dev:        a struct device of type scsi class
 207  * @dma_dev:    dma device for the host
 208  *
 209  * Note: You rarely need to worry about this unless you're in a
 210  * virtualised host environments, so use the simpler scsi_add_host()
 211  * function instead.
 212  *
 213  * Return value:
 214  *      0 on success / != 0 for error
 215  **/
 216 int scsi_add_host_with_dma(struct Scsi_Host *shost, struct device *dev,
 217                            struct device *dma_dev)
 218 {
 219         struct scsi_host_template *sht = shost->hostt;
 220         int error = -EINVAL;
 221
 222         shost_printk(KERN_INFO, shost, "%s\n",
 223                         sht->info ? sht->info(shost) : sht->name);
 224
 225         if (!shost->can_queue) {
 226                 shost_printk(KERN_ERR, shost,
 227                              "can_queue = 0 no longer supported\n");
 228                 goto fail;
 229         }
 230
 231         /* Use min_t(int, ...) in case shost->can_queue exceeds SHRT_MAX */
 232         shost->cmd_per_lun = min_t(int, shost->cmd_per_lun,
 233                                    shost->can_queue);
 234
 235         error = scsi_init_sense_cache(shost);
 236         if (error)
 237                 goto fail;
 238
 239         if (!shost->shost_gendev.parent)
 240                 shost->shost_gendev.parent = dev ? dev : &platform_bus;
 241         if (!dma_dev)
 242                 dma_dev = shost->shost_gendev.parent;
 243
 244         shost->dma_dev = dma_dev;
 245
 246         error = scsi_mq_setup_tags(shost);
 247         if (error)
 248                 goto fail;
 249
 250         /*
 251          * Increase usage count temporarily here so that calling
 252          * scsi_autopm_put_host() will trigger runtime idle if there is
 253          * nothing else preventing suspending the device.
 254          */
 255         pm_runtime_get_noresume(&shost->shost_gendev);
 256         pm_runtime_set_active(&shost->shost_gendev);
 257         pm_runtime_enable(&shost->shost_gendev);
 258         device_enable_async_suspend(&shost->shost_gendev);
 259
 260         error = device_add(&shost->shost_gendev);
 261         if (error)
 262                 goto out_disable_runtime_pm;
 263
 264         scsi_host_set_state(shost, SHOST_RUNNING);
 265         get_device(shost->shost_gendev.parent);
 266
 267         device_enable_async_suspend(&shost->shost_dev);
 268
 269         get_device(&shost->shost_gendev);
 270         error = device_add(&shost->shost_dev);
 271         if (error)
 272                 goto out_del_gendev;
 273
 274         if (shost->transportt->host_size) {
 275                 shost->shost_data = kzalloc(shost->transportt->host_size,
 276                                          GFP_KERNEL);
 277                 if (shost->shost_data == NULL) {
 278                         error = -ENOMEM;
 279                         goto out_del_dev;
 280                 }
 281         }
 282
 283         if (shost->transportt->create_work_queue) {
 284                 snprintf(shost->work_q_name, sizeof(shost->work_q_name),
 285                          "scsi_wq_%d", shost->host_no);
 286                 shost->work_q = alloc_workqueue("%s",
 287                         WQ_SYSFS | __WQ_LEGACY | WQ_MEM_RECLAIM | WQ_UNBOUND,
 288                         1, shost->work_q_name);
 289
 290                 if (!shost->work_q) {
 291                         error = -EINVAL;
 292                         goto out_del_dev;
 293                 }
 294         }
 295
 296         error = scsi_sysfs_add_host(shost);
 297         if (error)
 298                 goto out_del_dev;
 299
 300         scsi_proc_host_add(shost);
 301         scsi_autopm_put_host(shost);
 302         return error;
 303
 304         /*
 305          * Any host allocation in this function will be freed in
 306          * scsi_host_dev_release().
 307          */
 308  out_del_dev:
 309         device_del(&shost->shost_dev);
 310  out_del_gendev:
 311         /*
 312          * Host state is SHOST_RUNNING so we have to explicitly release
 313          * ->shost_dev.
 314          */
 315         put_device(&shost->shost_dev);
 316         device_del(&shost->shost_gendev);
 317  out_disable_runtime_pm:
 318         device_disable_async_suspend(&shost->shost_gendev);
 319         pm_runtime_disable(&shost->shost_gendev);
 320         pm_runtime_set_suspended(&shost->shost_gendev);
 321         pm_runtime_put_noidle(&shost->shost_gendev);
 322  fail:
 323         return error;
 324 }
 325 EXPORT_SYMBOL(scsi_add_host_with_dma);
 326
 327 static void scsi_host_dev_release(struct device *dev)
 328 {
 329         struct Scsi_Host *shost = dev_to_shost(dev);
 330         struct device *parent = dev->parent;
 331
 332         scsi_proc_hostdir_rm(shost->hostt);
 333
 334         /* Wait for functions invoked through call_rcu(&scmd->rcu, ...) */
 335         rcu_barrier();
 336
 337         if (shost->tmf_work_q)
 338                 destroy_workqueue(shost->tmf_work_q);
 339         if (shost->ehandler)
 340                 kthread_stop(shost->ehandler);
 341         if (shost->work_q)
 342                 destroy_workqueue(shost->work_q);
 343
 344         if (shost->shost_state == SHOST_CREATED) {
 345                 /*
 346                  * Free the shost_dev device name here if scsi_host_alloc()
 347                  * and scsi_host_put() have been called but neither
 348                  * scsi_host_add() nor scsi_host_remove() has been called.
 349                  * This avoids that the memory allocated for the shost_dev
 350                  * name is leaked.
 351                  */
 352                 kfree(dev_name(&shost->shost_dev));
 353         }
 354
 355         if (shost->tag_set.tags)
 356                 scsi_mq_destroy_tags(shost);
 357
 358         kfree(shost->shost_data);
 359
 360         ida_free(&host_index_ida, shost->host_no);
 361
 362         if (shost->shost_state != SHOST_CREATED)
 363                 put_device(parent);
 364         kfree(shost);
 365 }
 366
 367 static struct device_type scsi_host_type = {
 368         .name =         "scsi_host",
 369         .release =      scsi_host_dev_release,
 370 };
 371
 372 /**
 373  * scsi_host_alloc - register a scsi host adapter instance.
 374  * @sht:        pointer to scsi host template
 375  * @privsize:   extra bytes to allocate for driver
 376  *
 377  * Note:
 378  *      Allocate a new Scsi_Host and perform basic initialization.
 379  *      The host is not published to the scsi midlayer until scsi_add_host
 380  *      is called.
 381  *
 382  * Return value:
 383  *      Pointer to a new Scsi_Host
 384  **/
 385 struct Scsi_Host *scsi_host_alloc(struct scsi_host_template *sht, int privsize)
 386 {
 387         struct Scsi_Host *shost;
 388         int index;
 389
 390         shost = kzalloc(sizeof(struct Scsi_Host) + privsize, GFP_KERNEL);
 391         if (!shost)
 392                 return NULL;
 393
 394         shost->host_lock = &shost->default_lock;
 395         spin_lock_init(shost->host_lock);
 396         shost->shost_state = SHOST_CREATED;
 397         INIT_LIST_HEAD(&shost->__devices);
 398         INIT_LIST_HEAD(&shost->__targets);
 399         INIT_LIST_HEAD(&shost->eh_abort_list);
 400         INIT_LIST_HEAD(&shost->eh_cmd_q);
 401         INIT_LIST_HEAD(&shost->starved_list);
 402         init_waitqueue_head(&shost->host_wait);
 403         mutex_init(&shost->scan_mutex);
 404         init_waitqueue_head(&shost->targets_wq);
 405
 406         index = ida_alloc(&host_index_ida, GFP_KERNEL);
 407         if (index < 0) {
 408                 kfree(shost);
 409                 return NULL;
 410         }
 411         shost->host_no = index;
 412
 413         shost->dma_channel = 0xff;
 414
 415         /* These three are default values which can be overridden */
 416         shost->max_channel = 0;
 417         shost->max_id = 8;
 418         shost->max_lun = 8;
 419
 420         /* Give each shost a default transportt */
 421         shost->transportt = &blank_transport_template;
 422
 423         /*
 424          * All drivers right now should be able to handle 12 byte
 425          * commands.  Every so often there are requests for 16 byte
 426          * commands, but individual low-level drivers need to certify that
 427          * they actually do something sensible with such commands.
 428          */
 429         shost->max_cmd_len = 12;
 430         shost->hostt = sht;
 431         shost->this_id = sht->this_id;
 432         shost->can_queue = sht->can_queue;
 433         shost->sg_tablesize = sht->sg_tablesize;
 434         shost->sg_prot_tablesize = sht->sg_prot_tablesize;
 435         shost->cmd_per_lun = sht->cmd_per_lun;
 436         shost->no_write_same = sht->no_write_same;
 437         shost->host_tagset = sht->host_tagset;
 438
 439         if (shost_eh_deadline == -1 || !sht->eh_host_reset_handler)
 440                 shost->eh_deadline = -1;
 441         else if ((ulong) shost_eh_deadline * HZ > INT_MAX) {
 442                 shost_printk(KERN_WARNING, shost,
 443                              "eh_deadline %u too large, setting to %u\n",
 444                              shost_eh_deadline, INT_MAX / HZ);
 445                 shost->eh_deadline = INT_MAX;
 446         } else
 447                 shost->eh_deadline = shost_eh_deadline * HZ;
 448
 449         if (sht->supported_mode == MODE_UNKNOWN)
 450                 /* means we didn't set it ... default to INITIATOR */
 451                 shost->active_mode = MODE_INITIATOR;
 452         else
 453                 shost->active_mode = sht->supported_mode;
 454
 455         if (sht->max_host_blocked)
 456                 shost->max_host_blocked = sht->max_host_blocked;
 457         else
 458                 shost->max_host_blocked = SCSI_DEFAULT_HOST_BLOCKED;
 459
 460         /*
 461          * If the driver imposes no hard sector transfer limit, start at
 462          * machine infinity initially.
 463          */
 464         if (sht->max_sectors)
 465                 shost->max_sectors = sht->max_sectors;
 466         else
 467                 shost->max_sectors = SCSI_DEFAULT_MAX_SECTORS;
 468
 469         if (sht->max_segment_size)
 470                 shost->max_segment_size = sht->max_segment_size;
 471         else
 472                 shost->max_segment_size = BLK_MAX_SEGMENT_SIZE;
 473
 474         /*
 475          * assume a 4GB boundary, if not set
 476          */
 477         if (sht->dma_boundary)
 478                 shost->dma_boundary = sht->dma_boundary;
 479         else
 480                 shost->dma_boundary = 0xffffffff;
 481
 482         if (sht->virt_boundary_mask)
 483                 shost->virt_boundary_mask = sht->virt_boundary_mask;
 484
 485         device_initialize(&shost->shost_gendev);
 486         dev_set_name(&shost->shost_gendev, "host%d", shost->host_no);
 487         shost->shost_gendev.bus = &scsi_bus_type;
 488         shost->shost_gendev.type = &scsi_host_type;
 489         scsi_enable_async_suspend(&shost->shost_gendev);
 490
 491         device_initialize(&shost->shost_dev);
 492         shost->shost_dev.parent = &shost->shost_gendev;
 493         shost->shost_dev.class = &shost_class;
 494         dev_set_name(&shost->shost_dev, "host%d", shost->host_no);
 495         shost->shost_dev.groups = sht->shost_groups;
 496
 497         shost->ehandler = kthread_run(scsi_error_handler, shost,
 498                         "scsi_eh_%d", shost->host_no);
 499         if (IS_ERR(shost->ehandler)) {
 500                 shost_printk(KERN_WARNING, shost,
 501                         "error handler thread failed to spawn, error = %ld\n",
 502                         PTR_ERR(shost->ehandler));
 503                 shost->ehandler = NULL;
 504                 goto fail;
 505         }
 506
 507         shost->tmf_work_q = alloc_workqueue("scsi_tmf_%d",
 508                                         WQ_UNBOUND | WQ_MEM_RECLAIM | WQ_SYSFS,
 509                                            1, shost->host_no);
 510         if (!shost->tmf_work_q) {
 511                 shost_printk(KERN_WARNING, shost,
 512                              "failed to create tmf workq\n");
 513                 goto fail;
 514         }
 515         scsi_proc_hostdir_add(shost->hostt);
 516         return shost;
 517  fail:
 518         /*
 519          * Host state is still SHOST_CREATED and that is enough to release
 520          * ->shost_gendev. scsi_host_dev_release() will free
 521          * dev_name(&shost->shost_dev).
 522          */
 523         put_device(&shost->shost_gendev);
 524
 525         return NULL;
 526 }
 527 EXPORT_SYMBOL(scsi_host_alloc);
 528
 529 static int __scsi_host_match(struct device *dev, const void *data)
 530 {
 531         struct Scsi_Host *p;
 532         const unsigned short *hostnum = data;
 533
 534         p = class_to_shost(dev);
 535         return p->host_no == *hostnum;
 536 }
 537
 538 /**
 539  * scsi_host_lookup - get a reference to a Scsi_Host by host no
 540  * @hostnum:    host number to locate
 541  *
 542  * Return value:
 543  *      A pointer to located Scsi_Host or NULL.
 544  *
 545  *      The caller must do a scsi_host_put() to drop the reference
 546  *      that scsi_host_get() took. The put_device() below dropped
 547  *      the reference from class_find_device().
 548  **/
 549 struct Scsi_Host *scsi_host_lookup(unsigned short hostnum)
 550 {
 551         struct device *cdev;
 552         struct Scsi_Host *shost = NULL;
 553
 554         cdev = class_find_device(&shost_class, NULL, &hostnum,
 555                                  __scsi_host_match);
 556         if (cdev) {
 557                 shost = scsi_host_get(class_to_shost(cdev));
 558                 put_device(cdev);
 559         }
 560         return shost;
 561 }
 562 EXPORT_SYMBOL(scsi_host_lookup);
 563
 564 /**
 565  * scsi_host_get - inc a Scsi_Host ref count
 566  * @shost:      Pointer to Scsi_Host to inc.
 567  **/
 568 struct Scsi_Host *scsi_host_get(struct Scsi_Host *shost)
 569 {
 570         if ((shost->shost_state == SHOST_DEL) ||
 571                 !get_device(&shost->shost_gendev))
 572                 return NULL;
 573         return shost;
 574 }
 575 EXPORT_SYMBOL(scsi_host_get);
 576
 577 static bool scsi_host_check_in_flight(struct request *rq, void *data,
 578                                       bool reserved)
 579 {
 580         int *count = data;
 581         struct scsi_cmnd *cmd = blk_mq_rq_to_pdu(rq);
 582
 583         if (test_bit(SCMD_STATE_INFLIGHT, &cmd->state))
 584                 (*count)++;
 585
 586         return true;
 587 }
 588
 589 /**
 590  * scsi_host_busy - Return the host busy counter
 591  * @shost:      Pointer to Scsi_Host to inc.
 592  **/
 593 int scsi_host_busy(struct Scsi_Host *shost)
 594 {
 595         int cnt = 0;
 596
 597         blk_mq_tagset_busy_iter(&shost->tag_set,
 598                                 scsi_host_check_in_flight, &cnt);
 599         return cnt;
 600 }
 601 EXPORT_SYMBOL(scsi_host_busy);
 602
 603 /**
 604  * scsi_host_put - dec a Scsi_Host ref count
 605  * @shost:      Pointer to Scsi_Host to dec.
 606  **/
 607 void scsi_host_put(struct Scsi_Host *shost)
 608 {
 609         put_device(&shost->shost_gendev);
 610 }
 611 EXPORT_SYMBOL(scsi_host_put);
 612
 613 int scsi_init_hosts(void)
 614 {
 615         return class_register(&shost_class);
 616 }
 617
 618 void scsi_exit_hosts(void)
 619 {
 620         class_unregister(&shost_class);
 621         ida_destroy(&host_index_ida);
 622 }
 623
 624 int scsi_is_host_device(const struct device *dev)
 625 {
 626         return dev->type == &scsi_host_type;
 627 }
 628 EXPORT_SYMBOL(scsi_is_host_device);
 629
 630 /**
 631  * scsi_queue_work - Queue work to the Scsi_Host workqueue.
 632  * @shost:      Pointer to Scsi_Host.
 633  * @work:       Work to queue for execution.
 634  *
 635  * Return value:
 636  *      1 - work queued for execution
 637  *      0 - work is already queued
 638  *      -EINVAL - work queue doesn't exist
 639  **/
 640 int scsi_queue_work(struct Scsi_Host *shost, struct work_struct *work)
 641 {
 642         if (unlikely(!shost->work_q)) {
 643                 shost_printk(KERN_ERR, shost,
 644                         "ERROR: Scsi host '%s' attempted to queue scsi-work, "
 645                         "when no workqueue created.\n", shost->hostt->name);
 646                 dump_stack();
 647
 648                 return -EINVAL;
 649         }
 650
 651         return queue_work(shost->work_q, work);
 652 }
 653 EXPORT_SYMBOL_GPL(scsi_queue_work);
 654
 655 /**
 656  * scsi_flush_work - Flush a Scsi_Host's workqueue.
 657  * @shost:      Pointer to Scsi_Host.
 658  **/
 659 void scsi_flush_work(struct Scsi_Host *shost)
 660 {
 661         if (!shost->work_q) {
 662                 shost_printk(KERN_ERR, shost,
 663                         "ERROR: Scsi host '%s' attempted to flush scsi-work, "
 664                         "when no workqueue created.\n", shost->hostt->name);
 665                 dump_stack();
 666                 return;
 667         }
 668
 669         flush_workqueue(shost->work_q);
 670 }
 671 EXPORT_SYMBOL_GPL(scsi_flush_work);
 672
 673 static bool complete_all_cmds_iter(struct request *rq, void *data, bool rsvd)
 674 {
 675         struct scsi_cmnd *scmd = blk_mq_rq_to_pdu(rq);
 676         enum scsi_host_status status = *(enum scsi_host_status *)data;
 677
 678         scsi_dma_unmap(scmd);
 679         scmd->result = 0;
 680         set_host_byte(scmd, status);
 681         scsi_done(scmd);
 682         return true;
 683 }
 684
 685 /**
 686  * scsi_host_complete_all_commands - Terminate all running commands
 687  * @shost:      Scsi Host on which commands should be terminated
 688  * @status:     Status to be set for the terminated commands
 689  *
 690  * There is no protection against modification of the number
 691  * of outstanding commands. It is the responsibility of the
 692  * caller to ensure that concurrent I/O submission and/or
 693  * completion is stopped when calling this function.
 694  */
 695 void scsi_host_complete_all_commands(struct Scsi_Host *shost,
 696                                      enum scsi_host_status status)
 697 {
 698         blk_mq_tagset_busy_iter(&shost->tag_set, complete_all_cmds_iter,
 699                                 &status);
 700 }
 701 EXPORT_SYMBOL_GPL(scsi_host_complete_all_commands);
 702
 703 struct scsi_host_busy_iter_data {
 704         bool (*fn)(struct scsi_cmnd *, void *, bool);
 705         void *priv;
 706 };
 707
 708 static bool __scsi_host_busy_iter_fn(struct request *req, void *priv,
 709                                    bool reserved)
 710 {
 711         struct scsi_host_busy_iter_data *iter_data = priv;
 712         struct scsi_cmnd *sc = blk_mq_rq_to_pdu(req);
 713
 714         return iter_data->fn(sc, iter_data->priv, reserved);
 715 }
 716
 717 /**
 718  * scsi_host_busy_iter - Iterate over all busy commands
 719  * @shost:      Pointer to Scsi_Host.
 720  * @fn:         Function to call on each busy command
 721  * @priv:       Data pointer passed to @fn
 722  *
 723  * If locking against concurrent command completions is required
 724  * ithas to be provided by the caller
 725  **/
 726 void scsi_host_busy_iter(struct Scsi_Host *shost,
 727                          bool (*fn)(struct scsi_cmnd *, void *, bool),
 728                          void *priv)
 729 {
 730         struct scsi_host_busy_iter_data iter_data = {
 731                 .fn = fn,
 732                 .priv = priv,
 733         };
 734
 735         blk_mq_tagset_busy_iter(&shost->tag_set, __scsi_host_busy_iter_fn,
 736                                 &iter_data);
 737 }
 738 EXPORT_SYMBOL_GPL(scsi_host_busy_iter);