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         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         /* In case scsi_remove_host() has not been called. */
 345         scsi_proc_hostdir_rm(shost->hostt);
 346
 347         /* Wait for functions invoked through call_rcu(&scmd->rcu, ...) */
 348         rcu_barrier();
 349
 350         if (shost->tmf_work_q)
 351                 destroy_workqueue(shost->tmf_work_q);
 352         if (shost->ehandler)
 353                 kthread_stop(shost->ehandler);
 354         if (shost->work_q)
 355                 destroy_workqueue(shost->work_q);
 356
 357         if (shost->shost_state == SHOST_CREATED) {
 358                 /*
 359                  * Free the shost_dev device name here if scsi_host_alloc()
 360                  * and scsi_host_put() have been called but neither
 361                  * scsi_host_add() nor scsi_remove_host() has been called.
 362                  * This avoids that the memory allocated for the shost_dev
 363                  * name is leaked.
 364                  */
 365                 kfree(dev_name(&shost->shost_dev));
 366         }
 367
 368         kfree(shost->shost_data);
 369
 370         ida_free(&host_index_ida, shost->host_no);
 371
 372         if (shost->shost_state != SHOST_CREATED)
 373                 put_device(parent);
 374         kfree(shost);
 375 }
 376
 377 static struct device_type scsi_host_type = {
 378         .name =         "scsi_host",
 379         .release =      scsi_host_dev_release,
 380 };
 381
 382 /**
 383  * scsi_host_alloc - register a scsi host adapter instance.
 384  * @sht:        pointer to scsi host template
 385  * @privsize:   extra bytes to allocate for driver
 386  *
 387  * Note:
 388  *      Allocate a new Scsi_Host and perform basic initialization.
 389  *      The host is not published to the scsi midlayer until scsi_add_host
 390  *      is called.
 391  *
 392  * Return value:
 393  *      Pointer to a new Scsi_Host
 394  **/
 395 struct Scsi_Host *scsi_host_alloc(struct scsi_host_template *sht, int privsize)
 396 {
 397         struct Scsi_Host *shost;
 398         int index;
 399
 400         shost = kzalloc(sizeof(struct Scsi_Host) + privsize, GFP_KERNEL);
 401         if (!shost)
 402                 return NULL;
 403
 404         shost->host_lock = &shost->default_lock;
 405         spin_lock_init(shost->host_lock);
 406         shost->shost_state = SHOST_CREATED;
 407         INIT_LIST_HEAD(&shost->__devices);
 408         INIT_LIST_HEAD(&shost->__targets);
 409         INIT_LIST_HEAD(&shost->eh_abort_list);
 410         INIT_LIST_HEAD(&shost->eh_cmd_q);
 411         INIT_LIST_HEAD(&shost->starved_list);
 412         init_waitqueue_head(&shost->host_wait);
 413         mutex_init(&shost->scan_mutex);
 414
 415         index = ida_alloc(&host_index_ida, GFP_KERNEL);
 416         if (index < 0) {
 417                 kfree(shost);
 418                 return NULL;
 419         }
 420         shost->host_no = index;
 421
 422         shost->dma_channel = 0xff;
 423
 424         /* These three are default values which can be overridden */
 425         shost->max_channel = 0;
 426         shost->max_id = 8;
 427         shost->max_lun = 8;
 428
 429         /* Give each shost a default transportt */
 430         shost->transportt = &blank_transport_template;
 431
 432         /*
 433          * All drivers right now should be able to handle 12 byte
 434          * commands.  Every so often there are requests for 16 byte
 435          * commands, but individual low-level drivers need to certify that
 436          * they actually do something sensible with such commands.
 437          */
 438         shost->max_cmd_len = 12;
 439         shost->hostt = sht;
 440         shost->this_id = sht->this_id;
 441         shost->can_queue = sht->can_queue;
 442         shost->sg_tablesize = sht->sg_tablesize;
 443         shost->sg_prot_tablesize = sht->sg_prot_tablesize;
 444         shost->cmd_per_lun = sht->cmd_per_lun;
 445         shost->no_write_same = sht->no_write_same;
 446         shost->host_tagset = sht->host_tagset;
 447
 448         if (shost_eh_deadline == -1 || !sht->eh_host_reset_handler)
 449                 shost->eh_deadline = -1;
 450         else if ((ulong) shost_eh_deadline * HZ > INT_MAX) {
 451                 shost_printk(KERN_WARNING, shost,
 452                              "eh_deadline %u too large, setting to %u\n",
 453                              shost_eh_deadline, INT_MAX / HZ);
 454                 shost->eh_deadline = INT_MAX;
 455         } else
 456                 shost->eh_deadline = shost_eh_deadline * HZ;
 457
 458         if (sht->supported_mode == MODE_UNKNOWN)
 459                 /* means we didn't set it ... default to INITIATOR */
 460                 shost->active_mode = MODE_INITIATOR;
 461         else
 462                 shost->active_mode = sht->supported_mode;
 463
 464         if (sht->max_host_blocked)
 465                 shost->max_host_blocked = sht->max_host_blocked;
 466         else
 467                 shost->max_host_blocked = SCSI_DEFAULT_HOST_BLOCKED;
 468
 469         /*
 470          * If the driver imposes no hard sector transfer limit, start at
 471          * machine infinity initially.
 472          */
 473         if (sht->max_sectors)
 474                 shost->max_sectors = sht->max_sectors;
 475         else
 476                 shost->max_sectors = SCSI_DEFAULT_MAX_SECTORS;
 477
 478         if (sht->max_segment_size)
 479                 shost->max_segment_size = sht->max_segment_size;
 480         else
 481                 shost->max_segment_size = BLK_MAX_SEGMENT_SIZE;
 482
 483         /*
 484          * assume a 4GB boundary, if not set
 485          */
 486         if (sht->dma_boundary)
 487                 shost->dma_boundary = sht->dma_boundary;
 488         else
 489                 shost->dma_boundary = 0xffffffff;
 490
 491         if (sht->virt_boundary_mask)
 492                 shost->virt_boundary_mask = sht->virt_boundary_mask;
 493
 494         device_initialize(&shost->shost_gendev);
 495         dev_set_name(&shost->shost_gendev, "host%d", shost->host_no);
 496         shost->shost_gendev.bus = &scsi_bus_type;
 497         shost->shost_gendev.type = &scsi_host_type;
 498         scsi_enable_async_suspend(&shost->shost_gendev);
 499
 500         device_initialize(&shost->shost_dev);
 501         shost->shost_dev.parent = &shost->shost_gendev;
 502         shost->shost_dev.class = &shost_class;
 503         dev_set_name(&shost->shost_dev, "host%d", shost->host_no);
 504         shost->shost_dev.groups = sht->shost_groups;
 505
 506         shost->ehandler = kthread_run(scsi_error_handler, shost,
 507                         "scsi_eh_%d", shost->host_no);
 508         if (IS_ERR(shost->ehandler)) {
 509                 shost_printk(KERN_WARNING, shost,
 510                         "error handler thread failed to spawn, error = %ld\n",
 511                         PTR_ERR(shost->ehandler));
 512                 shost->ehandler = NULL;
 513                 goto fail;
 514         }
 515
 516         shost->tmf_work_q = alloc_workqueue("scsi_tmf_%d",
 517                                         WQ_UNBOUND | WQ_MEM_RECLAIM | WQ_SYSFS,
 518                                            1, shost->host_no);
 519         if (!shost->tmf_work_q) {
 520                 shost_printk(KERN_WARNING, shost,
 521                              "failed to create tmf workq\n");
 522                 goto fail;
 523         }
 524         if (scsi_proc_hostdir_add(shost->hostt) < 0)
 525                 goto fail;
 526         return shost;
 527  fail:
 528         /*
 529          * Host state is still SHOST_CREATED and that is enough to release
 530          * ->shost_gendev. scsi_host_dev_release() will free
 531          * dev_name(&shost->shost_dev).
 532          */
 533         put_device(&shost->shost_gendev);
 534
 535         return NULL;
 536 }
 537 EXPORT_SYMBOL(scsi_host_alloc);
 538
 539 static int __scsi_host_match(struct device *dev, const void *data)
 540 {
 541         struct Scsi_Host *p;
 542         const unsigned short *hostnum = data;
 543
 544         p = class_to_shost(dev);
 545         return p->host_no == *hostnum;
 546 }
 547
 548 /**
 549  * scsi_host_lookup - get a reference to a Scsi_Host by host no
 550  * @hostnum:    host number to locate
 551  *
 552  * Return value:
 553  *      A pointer to located Scsi_Host or NULL.
 554  *
 555  *      The caller must do a scsi_host_put() to drop the reference
 556  *      that scsi_host_get() took. The put_device() below dropped
 557  *      the reference from class_find_device().
 558  **/
 559 struct Scsi_Host *scsi_host_lookup(unsigned short hostnum)
 560 {
 561         struct device *cdev;
 562         struct Scsi_Host *shost = NULL;
 563
 564         cdev = class_find_device(&shost_class, NULL, &hostnum,
 565                                  __scsi_host_match);
 566         if (cdev) {
 567                 shost = scsi_host_get(class_to_shost(cdev));
 568                 put_device(cdev);
 569         }
 570         return shost;
 571 }
 572 EXPORT_SYMBOL(scsi_host_lookup);
 573
 574 /**
 575  * scsi_host_get - inc a Scsi_Host ref count
 576  * @shost:      Pointer to Scsi_Host to inc.
 577  **/
 578 struct Scsi_Host *scsi_host_get(struct Scsi_Host *shost)
 579 {
 580         if ((shost->shost_state == SHOST_DEL) ||
 581                 !get_device(&shost->shost_gendev))
 582                 return NULL;
 583         return shost;
 584 }
 585 EXPORT_SYMBOL(scsi_host_get);
 586
 587 static bool scsi_host_check_in_flight(struct request *rq, void *data)
 588 {
 589         int *count = data;
 590         struct scsi_cmnd *cmd = blk_mq_rq_to_pdu(rq);
 591
 592         if (test_bit(SCMD_STATE_INFLIGHT, &cmd->state))
 593                 (*count)++;
 594
 595         return true;
 596 }
 597
 598 /**
 599  * scsi_host_busy - Return the host busy counter
 600  * @shost:      Pointer to Scsi_Host to inc.
 601  **/
 602 int scsi_host_busy(struct Scsi_Host *shost)
 603 {
 604         int cnt = 0;
 605
 606         blk_mq_tagset_busy_iter(&shost->tag_set,
 607                                 scsi_host_check_in_flight, &cnt);
 608         return cnt;
 609 }
 610 EXPORT_SYMBOL(scsi_host_busy);
 611
 612 /**
 613  * scsi_host_put - dec a Scsi_Host ref count
 614  * @shost:      Pointer to Scsi_Host to dec.
 615  **/
 616 void scsi_host_put(struct Scsi_Host *shost)
 617 {
 618         put_device(&shost->shost_gendev);
 619 }
 620 EXPORT_SYMBOL(scsi_host_put);
 621
 622 int scsi_init_hosts(void)
 623 {
 624         return class_register(&shost_class);
 625 }
 626
 627 void scsi_exit_hosts(void)
 628 {
 629         class_unregister(&shost_class);
 630         ida_destroy(&host_index_ida);
 631 }
 632
 633 int scsi_is_host_device(const struct device *dev)
 634 {
 635         return dev->type == &scsi_host_type;
 636 }
 637 EXPORT_SYMBOL(scsi_is_host_device);
 638
 639 /**
 640  * scsi_queue_work - Queue work to the Scsi_Host workqueue.
 641  * @shost:      Pointer to Scsi_Host.
 642  * @work:       Work to queue for execution.
 643  *
 644  * Return value:
 645  *      1 - work queued for execution
 646  *      0 - work is already queued
 647  *      -EINVAL - work queue doesn't exist
 648  **/
 649 int scsi_queue_work(struct Scsi_Host *shost, struct work_struct *work)
 650 {
 651         if (unlikely(!shost->work_q)) {
 652                 shost_printk(KERN_ERR, shost,
 653                         "ERROR: Scsi host '%s' attempted to queue scsi-work, "
 654                         "when no workqueue created.\n", shost->hostt->name);
 655                 dump_stack();
 656
 657                 return -EINVAL;
 658         }
 659
 660         return queue_work(shost->work_q, work);
 661 }
 662 EXPORT_SYMBOL_GPL(scsi_queue_work);
 663
 664 /**
 665  * scsi_flush_work - Flush a Scsi_Host's workqueue.
 666  * @shost:      Pointer to Scsi_Host.
 667  **/
 668 void scsi_flush_work(struct Scsi_Host *shost)
 669 {
 670         if (!shost->work_q) {
 671                 shost_printk(KERN_ERR, shost,
 672                         "ERROR: Scsi host '%s' attempted to flush scsi-work, "
 673                         "when no workqueue created.\n", shost->hostt->name);
 674                 dump_stack();
 675                 return;
 676         }
 677
 678         flush_workqueue(shost->work_q);
 679 }
 680 EXPORT_SYMBOL_GPL(scsi_flush_work);
 681
 682 static bool complete_all_cmds_iter(struct request *rq, void *data)
 683 {
 684         struct scsi_cmnd *scmd = blk_mq_rq_to_pdu(rq);
 685         enum scsi_host_status status = *(enum scsi_host_status *)data;
 686
 687         scsi_dma_unmap(scmd);
 688         scmd->result = 0;
 689         set_host_byte(scmd, status);
 690         scsi_done(scmd);
 691         return true;
 692 }
 693
 694 /**
 695  * scsi_host_complete_all_commands - Terminate all running commands
 696  * @shost:      Scsi Host on which commands should be terminated
 697  * @status:     Status to be set for the terminated commands
 698  *
 699  * There is no protection against modification of the number
 700  * of outstanding commands. It is the responsibility of the
 701  * caller to ensure that concurrent I/O submission and/or
 702  * completion is stopped when calling this function.
 703  */
 704 void scsi_host_complete_all_commands(struct Scsi_Host *shost,
 705                                      enum scsi_host_status status)
 706 {
 707         blk_mq_tagset_busy_iter(&shost->tag_set, complete_all_cmds_iter,
 708                                 &status);
 709 }
 710 EXPORT_SYMBOL_GPL(scsi_host_complete_all_commands);
 711
 712 struct scsi_host_busy_iter_data {
 713         bool (*fn)(struct scsi_cmnd *, void *);
 714         void *priv;
 715 };
 716
 717 static bool __scsi_host_busy_iter_fn(struct request *req, void *priv)
 718 {
 719         struct scsi_host_busy_iter_data *iter_data = priv;
 720         struct scsi_cmnd *sc = blk_mq_rq_to_pdu(req);
 721
 722         return iter_data->fn(sc, iter_data->priv);
 723 }
 724
 725 /**
 726  * scsi_host_busy_iter - Iterate over all busy commands
 727  * @shost:      Pointer to Scsi_Host.
 728  * @fn:         Function to call on each busy command
 729  * @priv:       Data pointer passed to @fn
 730  *
 731  * If locking against concurrent command completions is required
 732  * ithas to be provided by the caller
 733  **/
 734 void scsi_host_busy_iter(struct Scsi_Host *shost,
 735                          bool (*fn)(struct scsi_cmnd *, void *),
 736                          void *priv)
 737 {
 738         struct scsi_host_busy_iter_data iter_data = {
 739                 .fn = fn,
 740                 .priv = priv,
 741         };
 742
 743         blk_mq_tagset_busy_iter(&shost->tag_set, __scsi_host_busy_iter_fn,
 744                                 &iter_data);
 745 }
 746 EXPORT_SYMBOL_GPL(scsi_host_busy_iter);