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         scsi_proc_hostdir_rm(shost->hostt);
 185
 186         /*
 187          * New SCSI devices cannot be attached anymore because of the SCSI host
 188          * state so drop the tag set refcnt. Wait until the tag set refcnt drops
 189          * to zero because .exit_cmd_priv implementations may need the host
 190          * pointer.
 191          */
 192         kref_put(&shost->tagset_refcnt, scsi_mq_free_tags);
 193         wait_for_completion(&shost->tagset_freed);
 194
 195         spin_lock_irqsave(shost->host_lock, flags);
 196         if (scsi_host_set_state(shost, SHOST_DEL))
 197                 BUG_ON(scsi_host_set_state(shost, SHOST_DEL_RECOVERY));
 198         spin_unlock_irqrestore(shost->host_lock, flags);
 199
 200         transport_unregister_device(&shost->shost_gendev);
 201         device_unregister(&shost->shost_dev);
 202         device_del(&shost->shost_gendev);
 203 }
 204 EXPORT_SYMBOL(scsi_remove_host);
 205
 206 /**
 207  * scsi_add_host_with_dma - add a scsi host with dma device
 208  * @shost:      scsi host pointer to add
 209  * @dev:        a struct device of type scsi class
 210  * @dma_dev:    dma device for the host
 211  *
 212  * Note: You rarely need to worry about this unless you're in a
 213  * virtualised host environments, so use the simpler scsi_add_host()
 214  * function instead.
 215  *
 216  * Return value:
 217  *      0 on success / != 0 for error
 218  **/
 219 int scsi_add_host_with_dma(struct Scsi_Host *shost, struct device *dev,
 220                            struct device *dma_dev)
 221 {
 222         struct scsi_host_template *sht = shost->hostt;
 223         int error = -EINVAL;
 224
 225         shost_printk(KERN_INFO, shost, "%s\n",
 226                         sht->info ? sht->info(shost) : sht->name);
 227
 228         if (!shost->can_queue) {
 229                 shost_printk(KERN_ERR, shost,
 230                              "can_queue = 0 no longer supported\n");
 231                 goto fail;
 232         }
 233
 234         /* Use min_t(int, ...) in case shost->can_queue exceeds SHRT_MAX */
 235         shost->cmd_per_lun = min_t(int, shost->cmd_per_lun,
 236                                    shost->can_queue);
 237
 238         error = scsi_init_sense_cache(shost);
 239         if (error)
 240                 goto fail;
 241
 242         if (!shost->shost_gendev.parent)
 243                 shost->shost_gendev.parent = dev ? dev : &platform_bus;
 244         if (!dma_dev)
 245                 dma_dev = shost->shost_gendev.parent;
 246
 247         shost->dma_dev = dma_dev;
 248
 249         if (dma_dev->dma_mask) {
 250                 shost->max_sectors = min_t(unsigned int, shost->max_sectors,
 251                                 dma_max_mapping_size(dma_dev) >> SECTOR_SHIFT);
 252         }
 253
 254         error = scsi_mq_setup_tags(shost);
 255         if (error)
 256                 goto fail;
 257
 258         kref_init(&shost->tagset_refcnt);
 259         init_completion(&shost->tagset_freed);
 260
 261         /*
 262          * Increase usage count temporarily here so that calling
 263          * scsi_autopm_put_host() will trigger runtime idle if there is
 264          * nothing else preventing suspending the device.
 265          */
 266         pm_runtime_get_noresume(&shost->shost_gendev);
 267         pm_runtime_set_active(&shost->shost_gendev);
 268         pm_runtime_enable(&shost->shost_gendev);
 269         device_enable_async_suspend(&shost->shost_gendev);
 270
 271         error = device_add(&shost->shost_gendev);
 272         if (error)
 273                 goto out_disable_runtime_pm;
 274
 275         scsi_host_set_state(shost, SHOST_RUNNING);
 276         get_device(shost->shost_gendev.parent);
 277
 278         device_enable_async_suspend(&shost->shost_dev);
 279
 280         get_device(&shost->shost_gendev);
 281         error = device_add(&shost->shost_dev);
 282         if (error)
 283                 goto out_del_gendev;
 284
 285         if (shost->transportt->host_size) {
 286                 shost->shost_data = kzalloc(shost->transportt->host_size,
 287                                          GFP_KERNEL);
 288                 if (shost->shost_data == NULL) {
 289                         error = -ENOMEM;
 290                         goto out_del_dev;
 291                 }
 292         }
 293
 294         if (shost->transportt->create_work_queue) {
 295                 snprintf(shost->work_q_name, sizeof(shost->work_q_name),
 296                          "scsi_wq_%d", shost->host_no);
 297                 shost->work_q = alloc_workqueue("%s",
 298                         WQ_SYSFS | __WQ_LEGACY | WQ_MEM_RECLAIM | WQ_UNBOUND,
 299                         1, shost->work_q_name);
 300
 301                 if (!shost->work_q) {
 302                         error = -EINVAL;
 303                         goto out_del_dev;
 304                 }
 305         }
 306
 307         error = scsi_sysfs_add_host(shost);
 308         if (error)
 309                 goto out_del_dev;
 310
 311         scsi_proc_host_add(shost);
 312         scsi_autopm_put_host(shost);
 313         return error;
 314
 315         /*
 316          * Any host allocation in this function will be freed in
 317          * scsi_host_dev_release().
 318          */
 319  out_del_dev:
 320         device_del(&shost->shost_dev);
 321  out_del_gendev:
 322         /*
 323          * Host state is SHOST_RUNNING so we have to explicitly release
 324          * ->shost_dev.
 325          */
 326         put_device(&shost->shost_dev);
 327         device_del(&shost->shost_gendev);
 328  out_disable_runtime_pm:
 329         device_disable_async_suspend(&shost->shost_gendev);
 330         pm_runtime_disable(&shost->shost_gendev);
 331         pm_runtime_set_suspended(&shost->shost_gendev);
 332         pm_runtime_put_noidle(&shost->shost_gendev);
 333         kref_put(&shost->tagset_refcnt, scsi_mq_free_tags);
 334  fail:
 335         return error;
 336 }
 337 EXPORT_SYMBOL(scsi_add_host_with_dma);
 338
 339 static void scsi_host_dev_release(struct device *dev)
 340 {
 341         struct Scsi_Host *shost = dev_to_shost(dev);
 342         struct device *parent = dev->parent;
 343
 344         /* Wait for functions invoked through call_rcu(&scmd->rcu, ...) */
 345         rcu_barrier();
 346
 347         if (shost->tmf_work_q)
 348                 destroy_workqueue(shost->tmf_work_q);
 349         if (shost->ehandler)
 350                 kthread_stop(shost->ehandler);
 351         if (shost->work_q)
 352                 destroy_workqueue(shost->work_q);
 353
 354         if (shost->shost_state == SHOST_CREATED) {
 355                 /*
 356                  * Free the shost_dev device name here if scsi_host_alloc()
 357                  * and scsi_host_put() have been called but neither
 358                  * scsi_host_add() nor scsi_host_remove() has been called.
 359                  * This avoids that the memory allocated for the shost_dev
 360                  * name is leaked.
 361                  */
 362                 kfree(dev_name(&shost->shost_dev));
 363         }
 364
 365         kfree(shost->shost_data);
 366
 367         ida_free(&host_index_ida, shost->host_no);
 368
 369         if (shost->shost_state != SHOST_CREATED)
 370                 put_device(parent);
 371         kfree(shost);
 372 }
 373
 374 static struct device_type scsi_host_type = {
 375         .name =         "scsi_host",
 376         .release =      scsi_host_dev_release,
 377 };
 378
 379 /**
 380  * scsi_host_alloc - register a scsi host adapter instance.
 381  * @sht:        pointer to scsi host template
 382  * @privsize:   extra bytes to allocate for driver
 383  *
 384  * Note:
 385  *      Allocate a new Scsi_Host and perform basic initialization.
 386  *      The host is not published to the scsi midlayer until scsi_add_host
 387  *      is called.
 388  *
 389  * Return value:
 390  *      Pointer to a new Scsi_Host
 391  **/
 392 struct Scsi_Host *scsi_host_alloc(struct scsi_host_template *sht, int privsize)
 393 {
 394         struct Scsi_Host *shost;
 395         int index;
 396
 397         shost = kzalloc(sizeof(struct Scsi_Host) + privsize, GFP_KERNEL);
 398         if (!shost)
 399                 return NULL;
 400
 401         shost->host_lock = &shost->default_lock;
 402         spin_lock_init(shost->host_lock);
 403         shost->shost_state = SHOST_CREATED;
 404         INIT_LIST_HEAD(&shost->__devices);
 405         INIT_LIST_HEAD(&shost->__targets);
 406         INIT_LIST_HEAD(&shost->eh_abort_list);
 407         INIT_LIST_HEAD(&shost->eh_cmd_q);
 408         INIT_LIST_HEAD(&shost->starved_list);
 409         init_waitqueue_head(&shost->host_wait);
 410         mutex_init(&shost->scan_mutex);
 411
 412         index = ida_alloc(&host_index_ida, GFP_KERNEL);
 413         if (index < 0) {
 414                 kfree(shost);
 415                 return NULL;
 416         }
 417         shost->host_no = index;
 418
 419         shost->dma_channel = 0xff;
 420
 421         /* These three are default values which can be overridden */
 422         shost->max_channel = 0;
 423         shost->max_id = 8;
 424         shost->max_lun = 8;
 425
 426         /* Give each shost a default transportt */
 427         shost->transportt = &blank_transport_template;
 428
 429         /*
 430          * All drivers right now should be able to handle 12 byte
 431          * commands.  Every so often there are requests for 16 byte
 432          * commands, but individual low-level drivers need to certify that
 433          * they actually do something sensible with such commands.
 434          */
 435         shost->max_cmd_len = 12;
 436         shost->hostt = sht;
 437         shost->this_id = sht->this_id;
 438         shost->can_queue = sht->can_queue;
 439         shost->sg_tablesize = sht->sg_tablesize;
 440         shost->sg_prot_tablesize = sht->sg_prot_tablesize;
 441         shost->cmd_per_lun = sht->cmd_per_lun;
 442         shost->no_write_same = sht->no_write_same;
 443         shost->host_tagset = sht->host_tagset;
 444
 445         if (shost_eh_deadline == -1 || !sht->eh_host_reset_handler)
 446                 shost->eh_deadline = -1;
 447         else if ((ulong) shost_eh_deadline * HZ > INT_MAX) {
 448                 shost_printk(KERN_WARNING, shost,
 449                              "eh_deadline %u too large, setting to %u\n",
 450                              shost_eh_deadline, INT_MAX / HZ);
 451                 shost->eh_deadline = INT_MAX;
 452         } else
 453                 shost->eh_deadline = shost_eh_deadline * HZ;
 454
 455         if (sht->supported_mode == MODE_UNKNOWN)
 456                 /* means we didn't set it ... default to INITIATOR */
 457                 shost->active_mode = MODE_INITIATOR;
 458         else
 459                 shost->active_mode = sht->supported_mode;
 460
 461         if (sht->max_host_blocked)
 462                 shost->max_host_blocked = sht->max_host_blocked;
 463         else
 464                 shost->max_host_blocked = SCSI_DEFAULT_HOST_BLOCKED;
 465
 466         /*
 467          * If the driver imposes no hard sector transfer limit, start at
 468          * machine infinity initially.
 469          */
 470         if (sht->max_sectors)
 471                 shost->max_sectors = sht->max_sectors;
 472         else
 473                 shost->max_sectors = SCSI_DEFAULT_MAX_SECTORS;
 474
 475         if (sht->max_segment_size)
 476                 shost->max_segment_size = sht->max_segment_size;
 477         else
 478                 shost->max_segment_size = BLK_MAX_SEGMENT_SIZE;
 479
 480         /*
 481          * assume a 4GB boundary, if not set
 482          */
 483         if (sht->dma_boundary)
 484                 shost->dma_boundary = sht->dma_boundary;
 485         else
 486                 shost->dma_boundary = 0xffffffff;
 487
 488         if (sht->virt_boundary_mask)
 489                 shost->virt_boundary_mask = sht->virt_boundary_mask;
 490
 491         device_initialize(&shost->shost_gendev);
 492         dev_set_name(&shost->shost_gendev, "host%d", shost->host_no);
 493         shost->shost_gendev.bus = &scsi_bus_type;
 494         shost->shost_gendev.type = &scsi_host_type;
 495         scsi_enable_async_suspend(&shost->shost_gendev);
 496
 497         device_initialize(&shost->shost_dev);
 498         shost->shost_dev.parent = &shost->shost_gendev;
 499         shost->shost_dev.class = &shost_class;
 500         dev_set_name(&shost->shost_dev, "host%d", shost->host_no);
 501         shost->shost_dev.groups = sht->shost_groups;
 502
 503         shost->ehandler = kthread_run(scsi_error_handler, shost,
 504                         "scsi_eh_%d", shost->host_no);
 505         if (IS_ERR(shost->ehandler)) {
 506                 shost_printk(KERN_WARNING, shost,
 507                         "error handler thread failed to spawn, error = %ld\n",
 508                         PTR_ERR(shost->ehandler));
 509                 shost->ehandler = NULL;
 510                 goto fail;
 511         }
 512
 513         shost->tmf_work_q = alloc_workqueue("scsi_tmf_%d",
 514                                         WQ_UNBOUND | WQ_MEM_RECLAIM | WQ_SYSFS,
 515                                            1, shost->host_no);
 516         if (!shost->tmf_work_q) {
 517                 shost_printk(KERN_WARNING, shost,
 518                              "failed to create tmf workq\n");
 519                 goto fail;
 520         }
 521         scsi_proc_hostdir_add(shost->hostt);
 522         return shost;
 523  fail:
 524         /*
 525          * Host state is still SHOST_CREATED and that is enough to release
 526          * ->shost_gendev. scsi_host_dev_release() will free
 527          * dev_name(&shost->shost_dev).
 528          */
 529         put_device(&shost->shost_gendev);
 530
 531         return NULL;
 532 }
 533 EXPORT_SYMBOL(scsi_host_alloc);
 534
 535 static int __scsi_host_match(struct device *dev, const void *data)
 536 {
 537         struct Scsi_Host *p;
 538         const unsigned short *hostnum = data;
 539
 540         p = class_to_shost(dev);
 541         return p->host_no == *hostnum;
 542 }
 543
 544 /**
 545  * scsi_host_lookup - get a reference to a Scsi_Host by host no
 546  * @hostnum:    host number to locate
 547  *
 548  * Return value:
 549  *      A pointer to located Scsi_Host or NULL.
 550  *
 551  *      The caller must do a scsi_host_put() to drop the reference
 552  *      that scsi_host_get() took. The put_device() below dropped
 553  *      the reference from class_find_device().
 554  **/
 555 struct Scsi_Host *scsi_host_lookup(unsigned short hostnum)
 556 {
 557         struct device *cdev;
 558         struct Scsi_Host *shost = NULL;
 559
 560         cdev = class_find_device(&shost_class, NULL, &hostnum,
 561                                  __scsi_host_match);
 562         if (cdev) {
 563                 shost = scsi_host_get(class_to_shost(cdev));
 564                 put_device(cdev);
 565         }
 566         return shost;
 567 }
 568 EXPORT_SYMBOL(scsi_host_lookup);
 569
 570 /**
 571  * scsi_host_get - inc a Scsi_Host ref count
 572  * @shost:      Pointer to Scsi_Host to inc.
 573  **/
 574 struct Scsi_Host *scsi_host_get(struct Scsi_Host *shost)
 575 {
 576         if ((shost->shost_state == SHOST_DEL) ||
 577                 !get_device(&shost->shost_gendev))
 578                 return NULL;
 579         return shost;
 580 }
 581 EXPORT_SYMBOL(scsi_host_get);
 582
 583 static bool scsi_host_check_in_flight(struct request *rq, void *data)
 584 {
 585         int *count = data;
 586         struct scsi_cmnd *cmd = blk_mq_rq_to_pdu(rq);
 587
 588         if (test_bit(SCMD_STATE_INFLIGHT, &cmd->state))
 589                 (*count)++;
 590
 591         return true;
 592 }
 593
 594 /**
 595  * scsi_host_busy - Return the host busy counter
 596  * @shost:      Pointer to Scsi_Host to inc.
 597  **/
 598 int scsi_host_busy(struct Scsi_Host *shost)
 599 {
 600         int cnt = 0;
 601
 602         blk_mq_tagset_busy_iter(&shost->tag_set,
 603                                 scsi_host_check_in_flight, &cnt);
 604         return cnt;
 605 }
 606 EXPORT_SYMBOL(scsi_host_busy);
 607
 608 /**
 609  * scsi_host_put - dec a Scsi_Host ref count
 610  * @shost:      Pointer to Scsi_Host to dec.
 611  **/
 612 void scsi_host_put(struct Scsi_Host *shost)
 613 {
 614         put_device(&shost->shost_gendev);
 615 }
 616 EXPORT_SYMBOL(scsi_host_put);
 617
 618 int scsi_init_hosts(void)
 619 {
 620         return class_register(&shost_class);
 621 }
 622
 623 void scsi_exit_hosts(void)
 624 {
 625         class_unregister(&shost_class);
 626         ida_destroy(&host_index_ida);
 627 }
 628
 629 int scsi_is_host_device(const struct device *dev)
 630 {
 631         return dev->type == &scsi_host_type;
 632 }
 633 EXPORT_SYMBOL(scsi_is_host_device);
 634
 635 /**
 636  * scsi_queue_work - Queue work to the Scsi_Host workqueue.
 637  * @shost:      Pointer to Scsi_Host.
 638  * @work:       Work to queue for execution.
 639  *
 640  * Return value:
 641  *      1 - work queued for execution
 642  *      0 - work is already queued
 643  *      -EINVAL - work queue doesn't exist
 644  **/
 645 int scsi_queue_work(struct Scsi_Host *shost, struct work_struct *work)
 646 {
 647         if (unlikely(!shost->work_q)) {
 648                 shost_printk(KERN_ERR, shost,
 649                         "ERROR: Scsi host '%s' attempted to queue scsi-work, "
 650                         "when no workqueue created.\n", shost->hostt->name);
 651                 dump_stack();
 652
 653                 return -EINVAL;
 654         }
 655
 656         return queue_work(shost->work_q, work);
 657 }
 658 EXPORT_SYMBOL_GPL(scsi_queue_work);
 659
 660 /**
 661  * scsi_flush_work - Flush a Scsi_Host's workqueue.
 662  * @shost:      Pointer to Scsi_Host.
 663  **/
 664 void scsi_flush_work(struct Scsi_Host *shost)
 665 {
 666         if (!shost->work_q) {
 667                 shost_printk(KERN_ERR, shost,
 668                         "ERROR: Scsi host '%s' attempted to flush scsi-work, "
 669                         "when no workqueue created.\n", shost->hostt->name);
 670                 dump_stack();
 671                 return;
 672         }
 673
 674         flush_workqueue(shost->work_q);
 675 }
 676 EXPORT_SYMBOL_GPL(scsi_flush_work);
 677
 678 static bool complete_all_cmds_iter(struct request *rq, void *data)
 679 {
 680         struct scsi_cmnd *scmd = blk_mq_rq_to_pdu(rq);
 681         enum scsi_host_status status = *(enum scsi_host_status *)data;
 682
 683         scsi_dma_unmap(scmd);
 684         scmd->result = 0;
 685         set_host_byte(scmd, status);
 686         scsi_done(scmd);
 687         return true;
 688 }
 689
 690 /**
 691  * scsi_host_complete_all_commands - Terminate all running commands
 692  * @shost:      Scsi Host on which commands should be terminated
 693  * @status:     Status to be set for the terminated commands
 694  *
 695  * There is no protection against modification of the number
 696  * of outstanding commands. It is the responsibility of the
 697  * caller to ensure that concurrent I/O submission and/or
 698  * completion is stopped when calling this function.
 699  */
 700 void scsi_host_complete_all_commands(struct Scsi_Host *shost,
 701                                      enum scsi_host_status status)
 702 {
 703         blk_mq_tagset_busy_iter(&shost->tag_set, complete_all_cmds_iter,
 704                                 &status);
 705 }
 706 EXPORT_SYMBOL_GPL(scsi_host_complete_all_commands);
 707
 708 struct scsi_host_busy_iter_data {
 709         bool (*fn)(struct scsi_cmnd *, void *);
 710         void *priv;
 711 };
 712
 713 static bool __scsi_host_busy_iter_fn(struct request *req, void *priv)
 714 {
 715         struct scsi_host_busy_iter_data *iter_data = priv;
 716         struct scsi_cmnd *sc = blk_mq_rq_to_pdu(req);
 717
 718         return iter_data->fn(sc, iter_data->priv);
 719 }
 720
 721 /**
 722  * scsi_host_busy_iter - Iterate over all busy commands
 723  * @shost:      Pointer to Scsi_Host.
 724  * @fn:         Function to call on each busy command
 725  * @priv:       Data pointer passed to @fn
 726  *
 727  * If locking against concurrent command completions is required
 728  * ithas to be provided by the caller
 729  **/
 730 void scsi_host_busy_iter(struct Scsi_Host *shost,
 731                          bool (*fn)(struct scsi_cmnd *, void *),
 732                          void *priv)
 733 {
 734         struct scsi_host_busy_iter_data iter_data = {
 735                 .fn = fn,
 736                 .priv = priv,
 737         };
 738
 739         blk_mq_tagset_busy_iter(&shost->tag_set, __scsi_host_busy_iter_fn,
 740                                 &iter_data);
 741 }
 742 EXPORT_SYMBOL_GPL(scsi_host_busy_iter);