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