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 EXPORT_SYMBOL(scsi_remove_host);
 195
 196 /**
 197  * scsi_add_host_with_dma - add a scsi host with dma device
 198  * @shost:      scsi host pointer to add
 199  * @dev:        a struct device of type scsi class
 200  * @dma_dev:    dma device for the host
 201  *
 202  * Note: You rarely need to worry about this unless you're in a
 203  * virtualised host environments, so use the simpler scsi_add_host()
 204  * function instead.
 205  *
 206  * Return value:
 207  *      0 on success / != 0 for error
 208  **/
 209 int scsi_add_host_with_dma(struct Scsi_Host *shost, struct device *dev,
 210                            struct device *dma_dev)
 211 {
 212         struct scsi_host_template *sht = shost->hostt;
 213         int error = -EINVAL;
 214
 215         shost_printk(KERN_INFO, shost, "%s\n",
 216                         sht->info ? sht->info(shost) : sht->name);
 217
 218         if (!shost->can_queue) {
 219                 shost_printk(KERN_ERR, shost,
 220                              "can_queue = 0 no longer supported\n");
 221                 goto fail;
 222         }
 223
 224         /* Use min_t(int, ...) in case shost->can_queue exceeds SHRT_MAX */
 225         shost->cmd_per_lun = min_t(int, shost->cmd_per_lun,
 226                                    shost->can_queue);
 227
 228         error = scsi_init_sense_cache(shost);
 229         if (error)
 230                 goto fail;
 231
 232         if (!shost->shost_gendev.parent)
 233                 shost->shost_gendev.parent = dev ? dev : &platform_bus;
 234         if (!dma_dev)
 235                 dma_dev = shost->shost_gendev.parent;
 236
 237         shost->dma_dev = dma_dev;
 238
 239         if (dma_dev->dma_mask) {
 240                 shost->max_sectors = min_t(unsigned int, shost->max_sectors,
 241                                 dma_max_mapping_size(dma_dev) >> SECTOR_SHIFT);
 242         }
 243
 244         error = scsi_mq_setup_tags(shost);
 245         if (error)
 246                 goto fail;
 247
 248         /*
 249          * Increase usage count temporarily here so that calling
 250          * scsi_autopm_put_host() will trigger runtime idle if there is
 251          * nothing else preventing suspending the device.
 252          */
 253         pm_runtime_get_noresume(&shost->shost_gendev);
 254         pm_runtime_set_active(&shost->shost_gendev);
 255         pm_runtime_enable(&shost->shost_gendev);
 256         device_enable_async_suspend(&shost->shost_gendev);
 257
 258         error = device_add(&shost->shost_gendev);
 259         if (error)
 260                 goto out_disable_runtime_pm;
 261
 262         scsi_host_set_state(shost, SHOST_RUNNING);
 263         get_device(shost->shost_gendev.parent);
 264
 265         device_enable_async_suspend(&shost->shost_dev);
 266
 267         get_device(&shost->shost_gendev);
 268         error = device_add(&shost->shost_dev);
 269         if (error)
 270                 goto out_del_gendev;
 271
 272         if (shost->transportt->host_size) {
 273                 shost->shost_data = kzalloc(shost->transportt->host_size,
 274                                          GFP_KERNEL);
 275                 if (shost->shost_data == NULL) {
 276                         error = -ENOMEM;
 277                         goto out_del_dev;
 278                 }
 279         }
 280
 281         if (shost->transportt->create_work_queue) {
 282                 snprintf(shost->work_q_name, sizeof(shost->work_q_name),
 283                          "scsi_wq_%d", shost->host_no);
 284                 shost->work_q = alloc_workqueue("%s",
 285                         WQ_SYSFS | __WQ_LEGACY | WQ_MEM_RECLAIM | WQ_UNBOUND,
 286                         1, shost->work_q_name);
 287
 288                 if (!shost->work_q) {
 289                         error = -EINVAL;
 290                         goto out_del_dev;
 291                 }
 292         }
 293
 294         error = scsi_sysfs_add_host(shost);
 295         if (error)
 296                 goto out_del_dev;
 297
 298         scsi_proc_host_add(shost);
 299         scsi_autopm_put_host(shost);
 300         return error;
 301
 302         /*
 303          * Any host allocation in this function will be freed in
 304          * scsi_host_dev_release().
 305          */
 306  out_del_dev:
 307         device_del(&shost->shost_dev);
 308  out_del_gendev:
 309         /*
 310          * Host state is SHOST_RUNNING so we have to explicitly release
 311          * ->shost_dev.
 312          */
 313         put_device(&shost->shost_dev);
 314         device_del(&shost->shost_gendev);
 315  out_disable_runtime_pm:
 316         device_disable_async_suspend(&shost->shost_gendev);
 317         pm_runtime_disable(&shost->shost_gendev);
 318         pm_runtime_set_suspended(&shost->shost_gendev);
 319         pm_runtime_put_noidle(&shost->shost_gendev);
 320  fail:
 321         return error;
 322 }
 323 EXPORT_SYMBOL(scsi_add_host_with_dma);
 324
 325 static void scsi_host_dev_release(struct device *dev)
 326 {
 327         struct Scsi_Host *shost = dev_to_shost(dev);
 328         struct device *parent = dev->parent;
 329
 330         scsi_proc_hostdir_rm(shost->hostt);
 331
 332         /* Wait for functions invoked through call_rcu(&scmd->rcu, ...) */
 333         rcu_barrier();
 334
 335         if (shost->tmf_work_q)
 336                 destroy_workqueue(shost->tmf_work_q);
 337         if (shost->ehandler)
 338                 kthread_stop(shost->ehandler);
 339         if (shost->work_q)
 340                 destroy_workqueue(shost->work_q);
 341
 342         if (shost->shost_state == SHOST_CREATED) {
 343                 /*
 344                  * Free the shost_dev device name here if scsi_host_alloc()
 345                  * and scsi_host_put() have been called but neither
 346                  * scsi_host_add() nor scsi_host_remove() has been called.
 347                  * This avoids that the memory allocated for the shost_dev
 348                  * name is leaked.
 349                  */
 350                 kfree(dev_name(&shost->shost_dev));
 351         }
 352
 353         if (shost->tag_set.tags)
 354                 scsi_mq_destroy_tags(shost);
 355
 356         kfree(shost->shost_data);
 357
 358         ida_free(&host_index_ida, shost->host_no);
 359
 360         if (shost->shost_state != SHOST_CREATED)
 361                 put_device(parent);
 362         kfree(shost);
 363 }
 364
 365 static struct device_type scsi_host_type = {
 366         .name =         "scsi_host",
 367         .release =      scsi_host_dev_release,
 368 };
 369
 370 /**
 371  * scsi_host_alloc - register a scsi host adapter instance.
 372  * @sht:        pointer to scsi host template
 373  * @privsize:   extra bytes to allocate for driver
 374  *
 375  * Note:
 376  *      Allocate a new Scsi_Host and perform basic initialization.
 377  *      The host is not published to the scsi midlayer until scsi_add_host
 378  *      is called.
 379  *
 380  * Return value:
 381  *      Pointer to a new Scsi_Host
 382  **/
 383 struct Scsi_Host *scsi_host_alloc(struct scsi_host_template *sht, int privsize)
 384 {
 385         struct Scsi_Host *shost;
 386         int index;
 387
 388         shost = kzalloc(sizeof(struct Scsi_Host) + privsize, GFP_KERNEL);
 389         if (!shost)
 390                 return NULL;
 391
 392         shost->host_lock = &shost->default_lock;
 393         spin_lock_init(shost->host_lock);
 394         shost->shost_state = SHOST_CREATED;
 395         INIT_LIST_HEAD(&shost->__devices);
 396         INIT_LIST_HEAD(&shost->__targets);
 397         INIT_LIST_HEAD(&shost->eh_abort_list);
 398         INIT_LIST_HEAD(&shost->eh_cmd_q);
 399         INIT_LIST_HEAD(&shost->starved_list);
 400         init_waitqueue_head(&shost->host_wait);
 401         mutex_init(&shost->scan_mutex);
 402
 403         index = ida_alloc(&host_index_ida, GFP_KERNEL);
 404         if (index < 0) {
 405                 kfree(shost);
 406                 return NULL;
 407         }
 408         shost->host_no = index;
 409
 410         shost->dma_channel = 0xff;
 411
 412         /* These three are default values which can be overridden */
 413         shost->max_channel = 0;
 414         shost->max_id = 8;
 415         shost->max_lun = 8;
 416
 417         /* Give each shost a default transportt */
 418         shost->transportt = &blank_transport_template;
 419
 420         /*
 421          * All drivers right now should be able to handle 12 byte
 422          * commands.  Every so often there are requests for 16 byte
 423          * commands, but individual low-level drivers need to certify that
 424          * they actually do something sensible with such commands.
 425          */
 426         shost->max_cmd_len = 12;
 427         shost->hostt = sht;
 428         shost->this_id = sht->this_id;
 429         shost->can_queue = sht->can_queue;
 430         shost->sg_tablesize = sht->sg_tablesize;
 431         shost->sg_prot_tablesize = sht->sg_prot_tablesize;
 432         shost->cmd_per_lun = sht->cmd_per_lun;
 433         shost->no_write_same = sht->no_write_same;
 434         shost->host_tagset = sht->host_tagset;
 435
 436         if (shost_eh_deadline == -1 || !sht->eh_host_reset_handler)
 437                 shost->eh_deadline = -1;
 438         else if ((ulong) shost_eh_deadline * HZ > INT_MAX) {
 439                 shost_printk(KERN_WARNING, shost,
 440                              "eh_deadline %u too large, setting to %u\n",
 441                              shost_eh_deadline, INT_MAX / HZ);
 442                 shost->eh_deadline = INT_MAX;
 443         } else
 444                 shost->eh_deadline = shost_eh_deadline * HZ;
 445
 446         if (sht->supported_mode == MODE_UNKNOWN)
 447                 /* means we didn't set it ... default to INITIATOR */
 448                 shost->active_mode = MODE_INITIATOR;
 449         else
 450                 shost->active_mode = sht->supported_mode;
 451
 452         if (sht->max_host_blocked)
 453                 shost->max_host_blocked = sht->max_host_blocked;
 454         else
 455                 shost->max_host_blocked = SCSI_DEFAULT_HOST_BLOCKED;
 456
 457         /*
 458          * If the driver imposes no hard sector transfer limit, start at
 459          * machine infinity initially.
 460          */
 461         if (sht->max_sectors)
 462                 shost->max_sectors = sht->max_sectors;
 463         else
 464                 shost->max_sectors = SCSI_DEFAULT_MAX_SECTORS;
 465
 466         if (sht->max_segment_size)
 467                 shost->max_segment_size = sht->max_segment_size;
 468         else
 469                 shost->max_segment_size = BLK_MAX_SEGMENT_SIZE;
 470
 471         /*
 472          * assume a 4GB boundary, if not set
 473          */
 474         if (sht->dma_boundary)
 475                 shost->dma_boundary = sht->dma_boundary;
 476         else
 477                 shost->dma_boundary = 0xffffffff;
 478
 479         if (sht->virt_boundary_mask)
 480                 shost->virt_boundary_mask = sht->virt_boundary_mask;
 481
 482         device_initialize(&shost->shost_gendev);
 483         dev_set_name(&shost->shost_gendev, "host%d", shost->host_no);
 484         shost->shost_gendev.bus = &scsi_bus_type;
 485         shost->shost_gendev.type = &scsi_host_type;
 486         scsi_enable_async_suspend(&shost->shost_gendev);
 487
 488         device_initialize(&shost->shost_dev);
 489         shost->shost_dev.parent = &shost->shost_gendev;
 490         shost->shost_dev.class = &shost_class;
 491         dev_set_name(&shost->shost_dev, "host%d", shost->host_no);
 492         shost->shost_dev.groups = sht->shost_groups;
 493
 494         shost->ehandler = kthread_run(scsi_error_handler, shost,
 495                         "scsi_eh_%d", shost->host_no);
 496         if (IS_ERR(shost->ehandler)) {
 497                 shost_printk(KERN_WARNING, shost,
 498                         "error handler thread failed to spawn, error = %ld\n",
 499                         PTR_ERR(shost->ehandler));
 500                 shost->ehandler = NULL;
 501                 goto fail;
 502         }
 503
 504         shost->tmf_work_q = alloc_workqueue("scsi_tmf_%d",
 505                                         WQ_UNBOUND | WQ_MEM_RECLAIM | WQ_SYSFS,
 506                                            1, shost->host_no);
 507         if (!shost->tmf_work_q) {
 508                 shost_printk(KERN_WARNING, shost,
 509                              "failed to create tmf workq\n");
 510                 goto fail;
 511         }
 512         scsi_proc_hostdir_add(shost->hostt);
 513         return shost;
 514  fail:
 515         /*
 516          * Host state is still SHOST_CREATED and that is enough to release
 517          * ->shost_gendev. scsi_host_dev_release() will free
 518          * dev_name(&shost->shost_dev).
 519          */
 520         put_device(&shost->shost_gendev);
 521
 522         return NULL;
 523 }
 524 EXPORT_SYMBOL(scsi_host_alloc);
 525
 526 static int __scsi_host_match(struct device *dev, const void *data)
 527 {
 528         struct Scsi_Host *p;
 529         const unsigned short *hostnum = data;
 530
 531         p = class_to_shost(dev);
 532         return p->host_no == *hostnum;
 533 }
 534
 535 /**
 536  * scsi_host_lookup - get a reference to a Scsi_Host by host no
 537  * @hostnum:    host number to locate
 538  *
 539  * Return value:
 540  *      A pointer to located Scsi_Host or NULL.
 541  *
 542  *      The caller must do a scsi_host_put() to drop the reference
 543  *      that scsi_host_get() took. The put_device() below dropped
 544  *      the reference from class_find_device().
 545  **/
 546 struct Scsi_Host *scsi_host_lookup(unsigned short hostnum)
 547 {
 548         struct device *cdev;
 549         struct Scsi_Host *shost = NULL;
 550
 551         cdev = class_find_device(&shost_class, NULL, &hostnum,
 552                                  __scsi_host_match);
 553         if (cdev) {
 554                 shost = scsi_host_get(class_to_shost(cdev));
 555                 put_device(cdev);
 556         }
 557         return shost;
 558 }
 559 EXPORT_SYMBOL(scsi_host_lookup);
 560
 561 /**
 562  * scsi_host_get - inc a Scsi_Host ref count
 563  * @shost:      Pointer to Scsi_Host to inc.
 564  **/
 565 struct Scsi_Host *scsi_host_get(struct Scsi_Host *shost)
 566 {
 567         if ((shost->shost_state == SHOST_DEL) ||
 568                 !get_device(&shost->shost_gendev))
 569                 return NULL;
 570         return shost;
 571 }
 572 EXPORT_SYMBOL(scsi_host_get);
 573
 574 static bool scsi_host_check_in_flight(struct request *rq, void *data)
 575 {
 576         int *count = data;
 577         struct scsi_cmnd *cmd = blk_mq_rq_to_pdu(rq);
 578
 579         if (test_bit(SCMD_STATE_INFLIGHT, &cmd->state))
 580                 (*count)++;
 581
 582         return true;
 583 }
 584
 585 /**
 586  * scsi_host_busy - Return the host busy counter
 587  * @shost:      Pointer to Scsi_Host to inc.
 588  **/
 589 int scsi_host_busy(struct Scsi_Host *shost)
 590 {
 591         int cnt = 0;
 592
 593         blk_mq_tagset_busy_iter(&shost->tag_set,
 594                                 scsi_host_check_in_flight, &cnt);
 595         return cnt;
 596 }
 597 EXPORT_SYMBOL(scsi_host_busy);
 598
 599 /**
 600  * scsi_host_put - dec a Scsi_Host ref count
 601  * @shost:      Pointer to Scsi_Host to dec.
 602  **/
 603 void scsi_host_put(struct Scsi_Host *shost)
 604 {
 605         put_device(&shost->shost_gendev);
 606 }
 607 EXPORT_SYMBOL(scsi_host_put);
 608
 609 int scsi_init_hosts(void)
 610 {
 611         return class_register(&shost_class);
 612 }
 613
 614 void scsi_exit_hosts(void)
 615 {
 616         class_unregister(&shost_class);
 617         ida_destroy(&host_index_ida);
 618 }
 619
 620 int scsi_is_host_device(const struct device *dev)
 621 {
 622         return dev->type == &scsi_host_type;
 623 }
 624 EXPORT_SYMBOL(scsi_is_host_device);
 625
 626 /**
 627  * scsi_queue_work - Queue work to the Scsi_Host workqueue.
 628  * @shost:      Pointer to Scsi_Host.
 629  * @work:       Work to queue for execution.
 630  *
 631  * Return value:
 632  *      1 - work queued for execution
 633  *      0 - work is already queued
 634  *      -EINVAL - work queue doesn't exist
 635  **/
 636 int scsi_queue_work(struct Scsi_Host *shost, struct work_struct *work)
 637 {
 638         if (unlikely(!shost->work_q)) {
 639                 shost_printk(KERN_ERR, shost,
 640                         "ERROR: Scsi host '%s' attempted to queue scsi-work, "
 641                         "when no workqueue created.\n", shost->hostt->name);
 642                 dump_stack();
 643
 644                 return -EINVAL;
 645         }
 646
 647         return queue_work(shost->work_q, work);
 648 }
 649 EXPORT_SYMBOL_GPL(scsi_queue_work);
 650
 651 /**
 652  * scsi_flush_work - Flush a Scsi_Host's workqueue.
 653  * @shost:      Pointer to Scsi_Host.
 654  **/
 655 void scsi_flush_work(struct Scsi_Host *shost)
 656 {
 657         if (!shost->work_q) {
 658                 shost_printk(KERN_ERR, shost,
 659                         "ERROR: Scsi host '%s' attempted to flush scsi-work, "
 660                         "when no workqueue created.\n", shost->hostt->name);
 661                 dump_stack();
 662                 return;
 663         }
 664
 665         flush_workqueue(shost->work_q);
 666 }
 667 EXPORT_SYMBOL_GPL(scsi_flush_work);
 668
 669 static bool complete_all_cmds_iter(struct request *rq, void *data)
 670 {
 671         struct scsi_cmnd *scmd = blk_mq_rq_to_pdu(rq);
 672         enum scsi_host_status status = *(enum scsi_host_status *)data;
 673
 674         scsi_dma_unmap(scmd);
 675         scmd->result = 0;
 676         set_host_byte(scmd, status);
 677         scsi_done(scmd);
 678         return true;
 679 }
 680
 681 /**
 682  * scsi_host_complete_all_commands - Terminate all running commands
 683  * @shost:      Scsi Host on which commands should be terminated
 684  * @status:     Status to be set for the terminated commands
 685  *
 686  * There is no protection against modification of the number
 687  * of outstanding commands. It is the responsibility of the
 688  * caller to ensure that concurrent I/O submission and/or
 689  * completion is stopped when calling this function.
 690  */
 691 void scsi_host_complete_all_commands(struct Scsi_Host *shost,
 692                                      enum scsi_host_status status)
 693 {
 694         blk_mq_tagset_busy_iter(&shost->tag_set, complete_all_cmds_iter,
 695                                 &status);
 696 }
 697 EXPORT_SYMBOL_GPL(scsi_host_complete_all_commands);
 698
 699 struct scsi_host_busy_iter_data {
 700         bool (*fn)(struct scsi_cmnd *, void *);
 701         void *priv;
 702 };
 703
 704 static bool __scsi_host_busy_iter_fn(struct request *req, void *priv)
 705 {
 706         struct scsi_host_busy_iter_data *iter_data = priv;
 707         struct scsi_cmnd *sc = blk_mq_rq_to_pdu(req);
 708
 709         return iter_data->fn(sc, iter_data->priv);
 710 }
 711
 712 /**
 713  * scsi_host_busy_iter - Iterate over all busy commands
 714  * @shost:      Pointer to Scsi_Host.
 715  * @fn:         Function to call on each busy command
 716  * @priv:       Data pointer passed to @fn
 717  *
 718  * If locking against concurrent command completions is required
 719  * ithas to be provided by the caller
 720  **/
 721 void scsi_host_busy_iter(struct Scsi_Host *shost,
 722                          bool (*fn)(struct scsi_cmnd *, void *),
 723                          void *priv)
 724 {
 725         struct scsi_host_busy_iter_data iter_data = {
 726                 .fn = fn,
 727                 .priv = priv,
 728         };
 729
 730         blk_mq_tagset_busy_iter(&shost->tag_set, __scsi_host_busy_iter_fn,
 731                                 &iter_data);
 732 }
 733 EXPORT_SYMBOL_GPL(scsi_host_busy_iter);