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  *  <[email protected]>
  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 <[email protected]>
  20  *
  21  *  Restructured scsi_host lists and associated functions.
  22  *  September 04, 2002 Mike Anderson ([email protected])
  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         const 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                 shost->work_q = alloc_workqueue(
 296                         "scsi_wq_%d",
 297                         WQ_SYSFS | __WQ_LEGACY | WQ_MEM_RECLAIM | WQ_UNBOUND, 1,
 298                         shost->host_no);
 299
 300                 if (!shost->work_q) {
 301                         error = -EINVAL;
 302                         goto out_del_dev;
 303                 }
 304         }
 305
 306         error = scsi_sysfs_add_host(shost);
 307         if (error)
 308                 goto out_del_dev;
 309
 310         scsi_proc_host_add(shost);
 311         scsi_autopm_put_host(shost);
 312         return error;
 313
 314         /*
 315          * Any host allocation in this function will be freed in
 316          * scsi_host_dev_release().
 317          */
 318  out_del_dev:
 319         device_del(&shost->shost_dev);
 320  out_del_gendev:
 321         /*
 322          * Host state is SHOST_RUNNING so we have to explicitly release
 323          * ->shost_dev.
 324          */
 325         put_device(&shost->shost_dev);
 326         device_del(&shost->shost_gendev);
 327  out_disable_runtime_pm:
 328         device_disable_async_suspend(&shost->shost_gendev);
 329         pm_runtime_disable(&shost->shost_gendev);
 330         pm_runtime_set_suspended(&shost->shost_gendev);
 331         pm_runtime_put_noidle(&shost->shost_gendev);
 332         kref_put(&shost->tagset_refcnt, scsi_mq_free_tags);
 333  fail:
 334         return error;
 335 }
 336 EXPORT_SYMBOL(scsi_add_host_with_dma);
 337
 338 static void scsi_host_dev_release(struct device *dev)
 339 {
 340         struct Scsi_Host *shost = dev_to_shost(dev);
 341         struct device *parent = dev->parent;
 342
 343         /* Wait for functions invoked through call_rcu(&scmd->rcu, ...) */
 344         rcu_barrier();
 345
 346         if (shost->tmf_work_q)
 347                 destroy_workqueue(shost->tmf_work_q);
 348         if (shost->ehandler)
 349                 kthread_stop(shost->ehandler);
 350         if (shost->work_q)
 351                 destroy_workqueue(shost->work_q);
 352
 353         if (shost->shost_state == SHOST_CREATED) {
 354                 /*
 355                  * Free the shost_dev device name and remove the proc host dir
 356                  * here if scsi_host_{alloc,put}() have been called but neither
 357                  * scsi_host_add() nor scsi_remove_host() has been called.
 358                  * This avoids that the memory allocated for the shost_dev
 359                  * name as well as the proc dir structure are leaked.
 360                  */
 361                 scsi_proc_hostdir_rm(shost->hostt);
 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 const 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(const 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         shost->queuecommand_may_block = sht->queuecommand_may_block;
 445
 446         if (shost_eh_deadline == -1 || !sht->eh_host_reset_handler)
 447                 shost->eh_deadline = -1;
 448         else if ((ulong) shost_eh_deadline * HZ > INT_MAX) {
 449                 shost_printk(KERN_WARNING, shost,
 450                              "eh_deadline %u too large, setting to %u\n",
 451                              shost_eh_deadline, INT_MAX / HZ);
 452                 shost->eh_deadline = INT_MAX;
 453         } else
 454                 shost->eh_deadline = shost_eh_deadline * HZ;
 455
 456         if (sht->supported_mode == MODE_UNKNOWN)
 457                 /* means we didn't set it ... default to INITIATOR */
 458                 shost->active_mode = MODE_INITIATOR;
 459         else
 460                 shost->active_mode = sht->supported_mode;
 461
 462         if (sht->max_host_blocked)
 463                 shost->max_host_blocked = sht->max_host_blocked;
 464         else
 465                 shost->max_host_blocked = SCSI_DEFAULT_HOST_BLOCKED;
 466
 467         /*
 468          * If the driver imposes no hard sector transfer limit, start at
 469          * machine infinity initially.
 470          */
 471         if (sht->max_sectors)
 472                 shost->max_sectors = sht->max_sectors;
 473         else
 474                 shost->max_sectors = SCSI_DEFAULT_MAX_SECTORS;
 475
 476         if (sht->max_segment_size)
 477                 shost->max_segment_size = sht->max_segment_size;
 478         else
 479                 shost->max_segment_size = BLK_MAX_SEGMENT_SIZE;
 480
 481         /* 32-byte (dword) is a common minimum for HBAs. */
 482         if (sht->dma_alignment)
 483                 shost->dma_alignment = sht->dma_alignment;
 484         else
 485                 shost->dma_alignment = 3;
 486
 487         /*
 488          * assume a 4GB boundary, if not set
 489          */
 490         if (sht->dma_boundary)
 491                 shost->dma_boundary = sht->dma_boundary;
 492         else
 493                 shost->dma_boundary = 0xffffffff;
 494
 495         if (sht->virt_boundary_mask)
 496                 shost->virt_boundary_mask = sht->virt_boundary_mask;
 497
 498         device_initialize(&shost->shost_gendev);
 499         dev_set_name(&shost->shost_gendev, "host%d", shost->host_no);
 500         shost->shost_gendev.bus = &scsi_bus_type;
 501         shost->shost_gendev.type = &scsi_host_type;
 502         scsi_enable_async_suspend(&shost->shost_gendev);
 503
 504         device_initialize(&shost->shost_dev);
 505         shost->shost_dev.parent = &shost->shost_gendev;
 506         shost->shost_dev.class = &shost_class;
 507         dev_set_name(&shost->shost_dev, "host%d", shost->host_no);
 508         shost->shost_dev.groups = sht->shost_groups;
 509
 510         shost->ehandler = kthread_run(scsi_error_handler, shost,
 511                         "scsi_eh_%d", shost->host_no);
 512         if (IS_ERR(shost->ehandler)) {
 513                 shost_printk(KERN_WARNING, shost,
 514                         "error handler thread failed to spawn, error = %ld\n",
 515                         PTR_ERR(shost->ehandler));
 516                 shost->ehandler = NULL;
 517                 goto fail;
 518         }
 519
 520         shost->tmf_work_q = alloc_workqueue("scsi_tmf_%d",
 521                                         WQ_UNBOUND | WQ_MEM_RECLAIM | WQ_SYSFS,
 522                                            1, shost->host_no);
 523         if (!shost->tmf_work_q) {
 524                 shost_printk(KERN_WARNING, shost,
 525                              "failed to create tmf workq\n");
 526                 goto fail;
 527         }
 528         if (scsi_proc_hostdir_add(shost->hostt) < 0)
 529                 goto fail;
 530         return shost;
 531  fail:
 532         /*
 533          * Host state is still SHOST_CREATED and that is enough to release
 534          * ->shost_gendev. scsi_host_dev_release() will free
 535          * dev_name(&shost->shost_dev).
 536          */
 537         put_device(&shost->shost_gendev);
 538
 539         return NULL;
 540 }
 541 EXPORT_SYMBOL(scsi_host_alloc);
 542
 543 static int __scsi_host_match(struct device *dev, const void *data)
 544 {
 545         struct Scsi_Host *p;
 546         const unsigned int *hostnum = data;
 547
 548         p = class_to_shost(dev);
 549         return p->host_no == *hostnum;
 550 }
 551
 552 /**
 553  * scsi_host_lookup - get a reference to a Scsi_Host by host no
 554  * @hostnum:    host number to locate
 555  *
 556  * Return value:
 557  *      A pointer to located Scsi_Host or NULL.
 558  *
 559  *      The caller must do a scsi_host_put() to drop the reference
 560  *      that scsi_host_get() took. The put_device() below dropped
 561  *      the reference from class_find_device().
 562  **/
 563 struct Scsi_Host *scsi_host_lookup(unsigned int hostnum)
 564 {
 565         struct device *cdev;
 566         struct Scsi_Host *shost = NULL;
 567
 568         cdev = class_find_device(&shost_class, NULL, &hostnum,
 569                                  __scsi_host_match);
 570         if (cdev) {
 571                 shost = scsi_host_get(class_to_shost(cdev));
 572                 put_device(cdev);
 573         }
 574         return shost;
 575 }
 576 EXPORT_SYMBOL(scsi_host_lookup);
 577
 578 /**
 579  * scsi_host_get - inc a Scsi_Host ref count
 580  * @shost:      Pointer to Scsi_Host to inc.
 581  **/
 582 struct Scsi_Host *scsi_host_get(struct Scsi_Host *shost)
 583 {
 584         if ((shost->shost_state == SHOST_DEL) ||
 585                 !get_device(&shost->shost_gendev))
 586                 return NULL;
 587         return shost;
 588 }
 589 EXPORT_SYMBOL(scsi_host_get);
 590
 591 static bool scsi_host_check_in_flight(struct request *rq, void *data)
 592 {
 593         int *count = data;
 594         struct scsi_cmnd *cmd = blk_mq_rq_to_pdu(rq);
 595
 596         if (test_bit(SCMD_STATE_INFLIGHT, &cmd->state))
 597                 (*count)++;
 598
 599         return true;
 600 }
 601
 602 /**
 603  * scsi_host_busy - Return the host busy counter
 604  * @shost:      Pointer to Scsi_Host to inc.
 605  **/
 606 int scsi_host_busy(struct Scsi_Host *shost)
 607 {
 608         int cnt = 0;
 609
 610         blk_mq_tagset_busy_iter(&shost->tag_set,
 611                                 scsi_host_check_in_flight, &cnt);
 612         return cnt;
 613 }
 614 EXPORT_SYMBOL(scsi_host_busy);
 615
 616 /**
 617  * scsi_host_put - dec a Scsi_Host ref count
 618  * @shost:      Pointer to Scsi_Host to dec.
 619  **/
 620 void scsi_host_put(struct Scsi_Host *shost)
 621 {
 622         put_device(&shost->shost_gendev);
 623 }
 624 EXPORT_SYMBOL(scsi_host_put);
 625
 626 int scsi_init_hosts(void)
 627 {
 628         return class_register(&shost_class);
 629 }
 630
 631 void scsi_exit_hosts(void)
 632 {
 633         class_unregister(&shost_class);
 634         ida_destroy(&host_index_ida);
 635 }
 636
 637 int scsi_is_host_device(const struct device *dev)
 638 {
 639         return dev->type == &scsi_host_type;
 640 }
 641 EXPORT_SYMBOL(scsi_is_host_device);
 642
 643 /**
 644  * scsi_queue_work - Queue work to the Scsi_Host workqueue.
 645  * @shost:      Pointer to Scsi_Host.
 646  * @work:       Work to queue for execution.
 647  *
 648  * Return value:
 649  *      1 - work queued for execution
 650  *      0 - work is already queued
 651  *      -EINVAL - work queue doesn't exist
 652  **/
 653 int scsi_queue_work(struct Scsi_Host *shost, struct work_struct *work)
 654 {
 655         if (unlikely(!shost->work_q)) {
 656                 shost_printk(KERN_ERR, shost,
 657                         "ERROR: Scsi host '%s' attempted to queue scsi-work, "
 658                         "when no workqueue created.\n", shost->hostt->name);
 659                 dump_stack();
 660
 661                 return -EINVAL;
 662         }
 663
 664         return queue_work(shost->work_q, work);
 665 }
 666 EXPORT_SYMBOL_GPL(scsi_queue_work);
 667
 668 /**
 669  * scsi_flush_work - Flush a Scsi_Host's workqueue.
 670  * @shost:      Pointer to Scsi_Host.
 671  **/
 672 void scsi_flush_work(struct Scsi_Host *shost)
 673 {
 674         if (!shost->work_q) {
 675                 shost_printk(KERN_ERR, shost,
 676                         "ERROR: Scsi host '%s' attempted to flush scsi-work, "
 677                         "when no workqueue created.\n", shost->hostt->name);
 678                 dump_stack();
 679                 return;
 680         }
 681
 682         flush_workqueue(shost->work_q);
 683 }
 684 EXPORT_SYMBOL_GPL(scsi_flush_work);
 685
 686 static bool complete_all_cmds_iter(struct request *rq, void *data)
 687 {
 688         struct scsi_cmnd *scmd = blk_mq_rq_to_pdu(rq);
 689         enum scsi_host_status status = *(enum scsi_host_status *)data;
 690
 691         scsi_dma_unmap(scmd);
 692         scmd->result = 0;
 693         set_host_byte(scmd, status);
 694         scsi_done(scmd);
 695         return true;
 696 }
 697
 698 /**
 699  * scsi_host_complete_all_commands - Terminate all running commands
 700  * @shost:      Scsi Host on which commands should be terminated
 701  * @status:     Status to be set for the terminated commands
 702  *
 703  * There is no protection against modification of the number
 704  * of outstanding commands. It is the responsibility of the
 705  * caller to ensure that concurrent I/O submission and/or
 706  * completion is stopped when calling this function.
 707  */
 708 void scsi_host_complete_all_commands(struct Scsi_Host *shost,
 709                                      enum scsi_host_status status)
 710 {
 711         blk_mq_tagset_busy_iter(&shost->tag_set, complete_all_cmds_iter,
 712                                 &status);
 713 }
 714 EXPORT_SYMBOL_GPL(scsi_host_complete_all_commands);
 715
 716 struct scsi_host_busy_iter_data {
 717         bool (*fn)(struct scsi_cmnd *, void *);
 718         void *priv;
 719 };
 720
 721 static bool __scsi_host_busy_iter_fn(struct request *req, void *priv)
 722 {
 723         struct scsi_host_busy_iter_data *iter_data = priv;
 724         struct scsi_cmnd *sc = blk_mq_rq_to_pdu(req);
 725
 726         return iter_data->fn(sc, iter_data->priv);
 727 }
 728
 729 /**
 730  * scsi_host_busy_iter - Iterate over all busy commands
 731  * @shost:      Pointer to Scsi_Host.
 732  * @fn:         Function to call on each busy command
 733  * @priv:       Data pointer passed to @fn
 734  *
 735  * If locking against concurrent command completions is required
 736  * ithas to be provided by the caller
 737  **/
 738 void scsi_host_busy_iter(struct Scsi_Host *shost,
 739                          bool (*fn)(struct scsi_cmnd *, void *),
 740                          void *priv)
 741 {
 742         struct scsi_host_busy_iter_data iter_data = {
 743                 .fn = fn,
 744                 .priv = priv,
 745         };
 746
 747         blk_mq_tagset_busy_iter(&shost->tag_set, __scsi_host_busy_iter_fn,
 748                                 &iter_data);
 749 }
 750 EXPORT_SYMBOL_GPL(scsi_host_busy_iter);