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
  42 #include "scsi_priv.h"
  43 #include "scsi_logging.h"
  44
  45
  46 static int shost_eh_deadline = -1;
  47
  48 module_param_named(eh_deadline, shost_eh_deadline, int, S_IRUGO|S_IWUSR);
  49 MODULE_PARM_DESC(eh_deadline,
  50                  "SCSI EH timeout in seconds (should be between 0 and 2^31-1)");
  51
  52 static DEFINE_IDA(host_index_ida);
  53
  54
  55 static void scsi_host_cls_release(struct device *dev)
  56 {
  57         put_device(&class_to_shost(dev)->shost_gendev);
  58 }
  59
  60 static struct class shost_class = {
  61         .name           = "scsi_host",
  62         .dev_release    = scsi_host_cls_release,
  63 };
  64
  65 /**
  66  *      scsi_host_set_state - Take the given host through the host state model.
  67  *      @shost: scsi host to change the state of.
  68  *      @state: state to change to.
  69  *
  70  *      Returns zero if unsuccessful or an error if the requested
  71  *      transition is illegal.
  72  **/
  73 int scsi_host_set_state(struct Scsi_Host *shost, enum scsi_host_state state)
  74 {
  75         enum scsi_host_state oldstate = shost->shost_state;
  76
  77         if (state == oldstate)
  78                 return 0;
  79
  80         switch (state) {
  81         case SHOST_CREATED:
  82                 /* There are no legal states that come back to
  83                  * created.  This is the manually initialised start
  84                  * state */
  85                 goto illegal;
  86
  87         case SHOST_RUNNING:
  88                 switch (oldstate) {
  89                 case SHOST_CREATED:
  90                 case SHOST_RECOVERY:
  91                         break;
  92                 default:
  93                         goto illegal;
  94                 }
  95                 break;
  96
  97         case SHOST_RECOVERY:
  98                 switch (oldstate) {
  99                 case SHOST_RUNNING:
 100                         break;
 101                 default:
 102                         goto illegal;
 103                 }
 104                 break;
 105
 106         case SHOST_CANCEL:
 107                 switch (oldstate) {
 108                 case SHOST_CREATED:
 109                 case SHOST_RUNNING:
 110                 case SHOST_CANCEL_RECOVERY:
 111                         break;
 112                 default:
 113                         goto illegal;
 114                 }
 115                 break;
 116
 117         case SHOST_DEL:
 118                 switch (oldstate) {
 119                 case SHOST_CANCEL:
 120                 case SHOST_DEL_RECOVERY:
 121                         break;
 122                 default:
 123                         goto illegal;
 124                 }
 125                 break;
 126
 127         case SHOST_CANCEL_RECOVERY:
 128                 switch (oldstate) {
 129                 case SHOST_CANCEL:
 130                 case SHOST_RECOVERY:
 131                         break;
 132                 default:
 133                         goto illegal;
 134                 }
 135                 break;
 136
 137         case SHOST_DEL_RECOVERY:
 138                 switch (oldstate) {
 139                 case SHOST_CANCEL_RECOVERY:
 140                         break;
 141                 default:
 142                         goto illegal;
 143                 }
 144                 break;
 145         }
 146         shost->shost_state = state;
 147         return 0;
 148
 149  illegal:
 150         SCSI_LOG_ERROR_RECOVERY(1,
 151                                 shost_printk(KERN_ERR, shost,
 152                                              "Illegal host state transition"
 153                                              "%s->%s\n",
 154                                              scsi_host_state_name(oldstate),
 155                                              scsi_host_state_name(state)));
 156         return -EINVAL;
 157 }
 158
 159 /**
 160  * scsi_remove_host - remove a scsi host
 161  * @shost:      a pointer to a scsi host to remove
 162  **/
 163 void scsi_remove_host(struct Scsi_Host *shost)
 164 {
 165         unsigned long flags;
 166
 167         mutex_lock(&shost->scan_mutex);
 168         spin_lock_irqsave(shost->host_lock, flags);
 169         if (scsi_host_set_state(shost, SHOST_CANCEL))
 170                 if (scsi_host_set_state(shost, SHOST_CANCEL_RECOVERY)) {
 171                         spin_unlock_irqrestore(shost->host_lock, flags);
 172                         mutex_unlock(&shost->scan_mutex);
 173                         return;
 174                 }
 175         spin_unlock_irqrestore(shost->host_lock, flags);
 176
 177         scsi_autopm_get_host(shost);
 178         flush_workqueue(shost->tmf_work_q);
 179         scsi_forget_host(shost);
 180         mutex_unlock(&shost->scan_mutex);
 181         scsi_proc_host_rm(shost);
 182
 183         spin_lock_irqsave(shost->host_lock, flags);
 184         if (scsi_host_set_state(shost, SHOST_DEL))
 185                 BUG_ON(scsi_host_set_state(shost, SHOST_DEL_RECOVERY));
 186         spin_unlock_irqrestore(shost->host_lock, flags);
 187
 188         transport_unregister_device(&shost->shost_gendev);
 189         device_unregister(&shost->shost_dev);
 190         device_del(&shost->shost_gendev);
 191 }
 192 EXPORT_SYMBOL(scsi_remove_host);
 193
 194 /**
 195  * scsi_add_host_with_dma - add a scsi host with dma device
 196  * @shost:      scsi host pointer to add
 197  * @dev:        a struct device of type scsi class
 198  * @dma_dev:    dma device for the host
 199  *
 200  * Note: You rarely need to worry about this unless you're in a
 201  * virtualised host environments, so use the simpler scsi_add_host()
 202  * function instead.
 203  *
 204  * Return value:
 205  *      0 on success / != 0 for error
 206  **/
 207 int scsi_add_host_with_dma(struct Scsi_Host *shost, struct device *dev,
 208                            struct device *dma_dev)
 209 {
 210         struct scsi_host_template *sht = shost->hostt;
 211         int error = -EINVAL;
 212
 213         shost_printk(KERN_INFO, shost, "%s\n",
 214                         sht->info ? sht->info(shost) : sht->name);
 215
 216         if (!shost->can_queue) {
 217                 shost_printk(KERN_ERR, shost,
 218                              "can_queue = 0 no longer supported\n");
 219                 goto fail;
 220         }
 221
 222         /* Use min_t(int, ...) in case shost->can_queue exceeds SHRT_MAX */
 223         shost->cmd_per_lun = min_t(int, shost->cmd_per_lun,
 224                                    shost->can_queue);
 225
 226         error = scsi_init_sense_cache(shost);
 227         if (error)
 228                 goto fail;
 229
 230         error = scsi_mq_setup_tags(shost);
 231         if (error)
 232                 goto fail;
 233
 234         if (!shost->shost_gendev.parent)
 235                 shost->shost_gendev.parent = dev ? dev : &platform_bus;
 236         if (!dma_dev)
 237                 dma_dev = shost->shost_gendev.parent;
 238
 239         shost->dma_dev = dma_dev;
 240
 241         /*
 242          * Increase usage count temporarily here so that calling
 243          * scsi_autopm_put_host() will trigger runtime idle if there is
 244          * nothing else preventing suspending the device.
 245          */
 246         pm_runtime_get_noresume(&shost->shost_gendev);
 247         pm_runtime_set_active(&shost->shost_gendev);
 248         pm_runtime_enable(&shost->shost_gendev);
 249         device_enable_async_suspend(&shost->shost_gendev);
 250
 251         error = device_add(&shost->shost_gendev);
 252         if (error)
 253                 goto out_disable_runtime_pm;
 254
 255         scsi_host_set_state(shost, SHOST_RUNNING);
 256         get_device(shost->shost_gendev.parent);
 257
 258         device_enable_async_suspend(&shost->shost_dev);
 259
 260         get_device(&shost->shost_gendev);
 261         error = device_add(&shost->shost_dev);
 262         if (error)
 263                 goto out_del_gendev;
 264
 265         if (shost->transportt->host_size) {
 266                 shost->shost_data = kzalloc(shost->transportt->host_size,
 267                                          GFP_KERNEL);
 268                 if (shost->shost_data == NULL) {
 269                         error = -ENOMEM;
 270                         goto out_del_dev;
 271                 }
 272         }
 273
 274         if (shost->transportt->create_work_queue) {
 275                 snprintf(shost->work_q_name, sizeof(shost->work_q_name),
 276                          "scsi_wq_%d", shost->host_no);
 277                 shost->work_q = create_singlethread_workqueue(
 278                                         shost->work_q_name);
 279                 if (!shost->work_q) {
 280                         error = -EINVAL;
 281                         goto out_del_dev;
 282                 }
 283         }
 284
 285         error = scsi_sysfs_add_host(shost);
 286         if (error)
 287                 goto out_del_dev;
 288
 289         scsi_proc_host_add(shost);
 290         scsi_autopm_put_host(shost);
 291         return error;
 292
 293         /*
 294          * Any host allocation in this function will be freed in
 295          * scsi_host_dev_release().
 296          */
 297  out_del_dev:
 298         device_del(&shost->shost_dev);
 299  out_del_gendev:
 300         /*
 301          * Host state is SHOST_RUNNING so we have to explicitly release
 302          * ->shost_dev.
 303          */
 304         put_device(&shost->shost_dev);
 305         device_del(&shost->shost_gendev);
 306  out_disable_runtime_pm:
 307         device_disable_async_suspend(&shost->shost_gendev);
 308         pm_runtime_disable(&shost->shost_gendev);
 309         pm_runtime_set_suspended(&shost->shost_gendev);
 310         pm_runtime_put_noidle(&shost->shost_gendev);
 311  fail:
 312         return error;
 313 }
 314 EXPORT_SYMBOL(scsi_add_host_with_dma);
 315
 316 static void scsi_host_dev_release(struct device *dev)
 317 {
 318         struct Scsi_Host *shost = dev_to_shost(dev);
 319         struct device *parent = dev->parent;
 320
 321         scsi_proc_hostdir_rm(shost->hostt);
 322
 323         /* Wait for functions invoked through call_rcu(&shost->rcu, ...) */
 324         rcu_barrier();
 325
 326         if (shost->tmf_work_q)
 327                 destroy_workqueue(shost->tmf_work_q);
 328         if (shost->ehandler)
 329                 kthread_stop(shost->ehandler);
 330         if (shost->work_q)
 331                 destroy_workqueue(shost->work_q);
 332
 333         if (shost->shost_state == SHOST_CREATED) {
 334                 /*
 335                  * Free the shost_dev device name here if scsi_host_alloc()
 336                  * and scsi_host_put() have been called but neither
 337                  * scsi_host_add() nor scsi_host_remove() has been called.
 338                  * This avoids that the memory allocated for the shost_dev
 339                  * name is leaked.
 340                  */
 341                 kfree(dev_name(&shost->shost_dev));
 342         }
 343
 344         if (shost->tag_set.tags)
 345                 scsi_mq_destroy_tags(shost);
 346
 347         kfree(shost->shost_data);
 348
 349         ida_simple_remove(&host_index_ida, shost->host_no);
 350
 351         if (shost->shost_state != SHOST_CREATED)
 352                 put_device(parent);
 353         kfree(shost);
 354 }
 355
 356 static struct device_type scsi_host_type = {
 357         .name =         "scsi_host",
 358         .release =      scsi_host_dev_release,
 359 };
 360
 361 /**
 362  * scsi_host_alloc - register a scsi host adapter instance.
 363  * @sht:        pointer to scsi host template
 364  * @privsize:   extra bytes to allocate for driver
 365  *
 366  * Note:
 367  *      Allocate a new Scsi_Host and perform basic initialization.
 368  *      The host is not published to the scsi midlayer until scsi_add_host
 369  *      is called.
 370  *
 371  * Return value:
 372  *      Pointer to a new Scsi_Host
 373  **/
 374 struct Scsi_Host *scsi_host_alloc(struct scsi_host_template *sht, int privsize)
 375 {
 376         struct Scsi_Host *shost;
 377         gfp_t gfp_mask = GFP_KERNEL;
 378         int index;
 379
 380         if (sht->unchecked_isa_dma && privsize)
 381                 gfp_mask |= __GFP_DMA;
 382
 383         shost = kzalloc(sizeof(struct Scsi_Host) + privsize, gfp_mask);
 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_cmd_q);
 393         INIT_LIST_HEAD(&shost->starved_list);
 394         init_waitqueue_head(&shost->host_wait);
 395         mutex_init(&shost->scan_mutex);
 396
 397         index = ida_simple_get(&host_index_ida, 0, 0, GFP_KERNEL);
 398         if (index < 0) {
 399                 kfree(shost);
 400                 return NULL;
 401         }
 402         shost->host_no = index;
 403
 404         shost->dma_channel = 0xff;
 405
 406         /* These three are default values which can be overridden */
 407         shost->max_channel = 0;
 408         shost->max_id = 8;
 409         shost->max_lun = 8;
 410
 411         /* Give each shost a default transportt */
 412         shost->transportt = &blank_transport_template;
 413
 414         /*
 415          * All drivers right now should be able to handle 12 byte
 416          * commands.  Every so often there are requests for 16 byte
 417          * commands, but individual low-level drivers need to certify that
 418          * they actually do something sensible with such commands.
 419          */
 420         shost->max_cmd_len = 12;
 421         shost->hostt = sht;
 422         shost->this_id = sht->this_id;
 423         shost->can_queue = sht->can_queue;
 424         shost->sg_tablesize = sht->sg_tablesize;
 425         shost->sg_prot_tablesize = sht->sg_prot_tablesize;
 426         shost->cmd_per_lun = sht->cmd_per_lun;
 427         shost->unchecked_isa_dma = sht->unchecked_isa_dma;
 428         shost->no_write_same = sht->no_write_same;
 429
 430         if (shost_eh_deadline == -1 || !sht->eh_host_reset_handler)
 431                 shost->eh_deadline = -1;
 432         else if ((ulong) shost_eh_deadline * HZ > INT_MAX) {
 433                 shost_printk(KERN_WARNING, shost,
 434                              "eh_deadline %u too large, setting to %u\n",
 435                              shost_eh_deadline, INT_MAX / HZ);
 436                 shost->eh_deadline = INT_MAX;
 437         } else
 438                 shost->eh_deadline = shost_eh_deadline * HZ;
 439
 440         if (sht->supported_mode == MODE_UNKNOWN)
 441                 /* means we didn't set it ... default to INITIATOR */
 442                 shost->active_mode = MODE_INITIATOR;
 443         else
 444                 shost->active_mode = sht->supported_mode;
 445
 446         if (sht->max_host_blocked)
 447                 shost->max_host_blocked = sht->max_host_blocked;
 448         else
 449                 shost->max_host_blocked = SCSI_DEFAULT_HOST_BLOCKED;
 450
 451         /*
 452          * If the driver imposes no hard sector transfer limit, start at
 453          * machine infinity initially.
 454          */
 455         if (sht->max_sectors)
 456                 shost->max_sectors = sht->max_sectors;
 457         else
 458                 shost->max_sectors = SCSI_DEFAULT_MAX_SECTORS;
 459
 460         if (sht->max_segment_size)
 461                 shost->max_segment_size = sht->max_segment_size;
 462         else
 463                 shost->max_segment_size = BLK_MAX_SEGMENT_SIZE;
 464
 465         /*
 466          * assume a 4GB boundary, if not set
 467          */
 468         if (sht->dma_boundary)
 469                 shost->dma_boundary = sht->dma_boundary;
 470         else
 471                 shost->dma_boundary = 0xffffffff;
 472
 473         if (sht->virt_boundary_mask)
 474                 shost->virt_boundary_mask = sht->virt_boundary_mask;
 475
 476         device_initialize(&shost->shost_gendev);
 477         dev_set_name(&shost->shost_gendev, "host%d", shost->host_no);
 478         shost->shost_gendev.bus = &scsi_bus_type;
 479         shost->shost_gendev.type = &scsi_host_type;
 480
 481         device_initialize(&shost->shost_dev);
 482         shost->shost_dev.parent = &shost->shost_gendev;
 483         shost->shost_dev.class = &shost_class;
 484         dev_set_name(&shost->shost_dev, "host%d", shost->host_no);
 485         shost->shost_dev.groups = scsi_sysfs_shost_attr_groups;
 486
 487         shost->ehandler = kthread_run(scsi_error_handler, shost,
 488                         "scsi_eh_%d", shost->host_no);
 489         if (IS_ERR(shost->ehandler)) {
 490                 shost_printk(KERN_WARNING, shost,
 491                         "error handler thread failed to spawn, error = %ld\n",
 492                         PTR_ERR(shost->ehandler));
 493                 shost->ehandler = NULL;
 494                 goto fail;
 495         }
 496
 497         shost->tmf_work_q = alloc_workqueue("scsi_tmf_%d",
 498                                             WQ_UNBOUND | WQ_MEM_RECLAIM,
 499                                            1, shost->host_no);
 500         if (!shost->tmf_work_q) {
 501                 shost_printk(KERN_WARNING, shost,
 502                              "failed to create tmf workq\n");
 503                 goto fail;
 504         }
 505         scsi_proc_hostdir_add(shost->hostt);
 506         return shost;
 507  fail:
 508         /*
 509          * Host state is still SHOST_CREATED and that is enough to release
 510          * ->shost_gendev. scsi_host_dev_release() will free
 511          * dev_name(&shost->shost_dev).
 512          */
 513         put_device(&shost->shost_gendev);
 514
 515         return NULL;
 516 }
 517 EXPORT_SYMBOL(scsi_host_alloc);
 518
 519 static int __scsi_host_match(struct device *dev, const void *data)
 520 {
 521         struct Scsi_Host *p;
 522         const unsigned short *hostnum = data;
 523
 524         p = class_to_shost(dev);
 525         return p->host_no == *hostnum;
 526 }
 527
 528 /**
 529  * scsi_host_lookup - get a reference to a Scsi_Host by host no
 530  * @hostnum:    host number to locate
 531  *
 532  * Return value:
 533  *      A pointer to located Scsi_Host or NULL.
 534  *
 535  *      The caller must do a scsi_host_put() to drop the reference
 536  *      that scsi_host_get() took. The put_device() below dropped
 537  *      the reference from class_find_device().
 538  **/
 539 struct Scsi_Host *scsi_host_lookup(unsigned short hostnum)
 540 {
 541         struct device *cdev;
 542         struct Scsi_Host *shost = NULL;
 543
 544         cdev = class_find_device(&shost_class, NULL, &hostnum,
 545                                  __scsi_host_match);
 546         if (cdev) {
 547                 shost = scsi_host_get(class_to_shost(cdev));
 548                 put_device(cdev);
 549         }
 550         return shost;
 551 }
 552 EXPORT_SYMBOL(scsi_host_lookup);
 553
 554 /**
 555  * scsi_host_get - inc a Scsi_Host ref count
 556  * @shost:      Pointer to Scsi_Host to inc.
 557  **/
 558 struct Scsi_Host *scsi_host_get(struct Scsi_Host *shost)
 559 {
 560         if ((shost->shost_state == SHOST_DEL) ||
 561                 !get_device(&shost->shost_gendev))
 562                 return NULL;
 563         return shost;
 564 }
 565 EXPORT_SYMBOL(scsi_host_get);
 566
 567 /**
 568  * scsi_host_busy - Return the host busy counter
 569  * @shost:      Pointer to Scsi_Host to inc.
 570  **/
 571 int scsi_host_busy(struct Scsi_Host *shost)
 572 {
 573         return atomic_read(&shost->host_busy);
 574 }
 575 EXPORT_SYMBOL(scsi_host_busy);
 576
 577 /**
 578  * scsi_host_put - dec a Scsi_Host ref count
 579  * @shost:      Pointer to Scsi_Host to dec.
 580  **/
 581 void scsi_host_put(struct Scsi_Host *shost)
 582 {
 583         put_device(&shost->shost_gendev);
 584 }
 585 EXPORT_SYMBOL(scsi_host_put);
 586
 587 int scsi_init_hosts(void)
 588 {
 589         return class_register(&shost_class);
 590 }
 591
 592 void scsi_exit_hosts(void)
 593 {
 594         class_unregister(&shost_class);
 595         ida_destroy(&host_index_ida);
 596 }
 597
 598 int scsi_is_host_device(const struct device *dev)
 599 {
 600         return dev->type == &scsi_host_type;
 601 }
 602 EXPORT_SYMBOL(scsi_is_host_device);
 603
 604 /**
 605  * scsi_queue_work - Queue work to the Scsi_Host workqueue.
 606  * @shost:      Pointer to Scsi_Host.
 607  * @work:       Work to queue for execution.
 608  *
 609  * Return value:
 610  *      1 - work queued for execution
 611  *      0 - work is already queued
 612  *      -EINVAL - work queue doesn't exist
 613  **/
 614 int scsi_queue_work(struct Scsi_Host *shost, struct work_struct *work)
 615 {
 616         if (unlikely(!shost->work_q)) {
 617                 shost_printk(KERN_ERR, shost,
 618                         "ERROR: Scsi host '%s' attempted to queue scsi-work, "
 619                         "when no workqueue created.\n", shost->hostt->name);
 620                 dump_stack();
 621
 622                 return -EINVAL;
 623         }
 624
 625         return queue_work(shost->work_q, work);
 626 }
 627 EXPORT_SYMBOL_GPL(scsi_queue_work);
 628
 629 /**
 630  * scsi_flush_work - Flush a Scsi_Host's workqueue.
 631  * @shost:      Pointer to Scsi_Host.
 632  **/
 633 void scsi_flush_work(struct Scsi_Host *shost)
 634 {
 635         if (!shost->work_q) {
 636                 shost_printk(KERN_ERR, shost,
 637                         "ERROR: Scsi host '%s' attempted to flush scsi-work, "
 638                         "when no workqueue created.\n", shost->hostt->name);
 639                 dump_stack();
 640                 return;
 641         }
 642
 643         flush_workqueue(shost->work_q);
 644 }
 645 EXPORT_SYMBOL_GPL(scsi_flush_work);