root/drivers/scsi/hosts.c

DEFINITIONS

1. scsi_host_cls_release
2. scsi_host_set_state
3. scsi_remove_host
4. scsi_add_host_with_dma
5. scsi_host_dev_release
6. scsi_host_alloc
7. __scsi_host_match
8. scsi_host_lookup
9. scsi_host_get
10. scsi_host_busy
11. scsi_host_put
12. scsi_init_hosts
13. scsi_exit_hosts
14. scsi_is_host_device
15. scsi_queue_work
16. scsi_flush_work

   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         error = scsi_init_sense_cache(shost);
 223         if (error)
 224                 goto fail;
 225 
 226         error = scsi_mq_setup_tags(shost);
 227         if (error)
 228                 goto fail;
 229 
 230         if (!shost->shost_gendev.parent)
 231                 shost->shost_gendev.parent = dev ? dev : &platform_bus;
 232         if (!dma_dev)
 233                 dma_dev = shost->shost_gendev.parent;
 234 
 235         shost->dma_dev = dma_dev;
 236 
 237         /*
 238          * Increase usage count temporarily here so that calling
 239          * scsi_autopm_put_host() will trigger runtime idle if there is
 240          * nothing else preventing suspending the device.
 241          */
 242         pm_runtime_get_noresume(&shost->shost_gendev);
 243         pm_runtime_set_active(&shost->shost_gendev);
 244         pm_runtime_enable(&shost->shost_gendev);
 245         device_enable_async_suspend(&shost->shost_gendev);
 246 
 247         error = device_add(&shost->shost_gendev);
 248         if (error)
 249                 goto out_disable_runtime_pm;
 250 
 251         scsi_host_set_state(shost, SHOST_RUNNING);
 252         get_device(shost->shost_gendev.parent);
 253 
 254         device_enable_async_suspend(&shost->shost_dev);
 255 
 256         error = device_add(&shost->shost_dev);
 257         if (error)
 258                 goto out_del_gendev;
 259 
 260         get_device(&shost->shost_gendev);
 261 
 262         if (shost->transportt->host_size) {
 263                 shost->shost_data = kzalloc(shost->transportt->host_size,
 264                                          GFP_KERNEL);
 265                 if (shost->shost_data == NULL) {
 266                         error = -ENOMEM;
 267                         goto out_del_dev;
 268                 }
 269         }
 270 
 271         if (shost->transportt->create_work_queue) {
 272                 snprintf(shost->work_q_name, sizeof(shost->work_q_name),
 273                          "scsi_wq_%d", shost->host_no);
 274                 shost->work_q = create_singlethread_workqueue(
 275                                         shost->work_q_name);
 276                 if (!shost->work_q) {
 277                         error = -EINVAL;
 278                         goto out_free_shost_data;
 279                 }
 280         }
 281 
 282         error = scsi_sysfs_add_host(shost);
 283         if (error)
 284                 goto out_destroy_host;
 285 
 286         scsi_proc_host_add(shost);
 287         scsi_autopm_put_host(shost);
 288         return error;
 289 
 290  out_destroy_host:
 291         if (shost->work_q)
 292                 destroy_workqueue(shost->work_q);
 293  out_free_shost_data:
 294         kfree(shost->shost_data);
 295  out_del_dev:
 296         device_del(&shost->shost_dev);
 297  out_del_gendev:
 298         device_del(&shost->shost_gendev);
 299  out_disable_runtime_pm:
 300         device_disable_async_suspend(&shost->shost_gendev);
 301         pm_runtime_disable(&shost->shost_gendev);
 302         pm_runtime_set_suspended(&shost->shost_gendev);
 303         pm_runtime_put_noidle(&shost->shost_gendev);
 304         scsi_mq_destroy_tags(shost);
 305  fail:
 306         return error;
 307 }
 308 EXPORT_SYMBOL(scsi_add_host_with_dma);
 309 
 310 static void scsi_host_dev_release(struct device *dev)
 311 {
 312         struct Scsi_Host *shost = dev_to_shost(dev);
 313         struct device *parent = dev->parent;
 314 
 315         scsi_proc_hostdir_rm(shost->hostt);
 316 
 317         /* Wait for functions invoked through call_rcu(&shost->rcu, ...) */
 318         rcu_barrier();
 319 
 320         if (shost->tmf_work_q)
 321                 destroy_workqueue(shost->tmf_work_q);
 322         if (shost->ehandler)
 323                 kthread_stop(shost->ehandler);
 324         if (shost->work_q)
 325                 destroy_workqueue(shost->work_q);
 326 
 327         if (shost->shost_state == SHOST_CREATED) {
 328                 /*
 329                  * Free the shost_dev device name here if scsi_host_alloc()
 330                  * and scsi_host_put() have been called but neither
 331                  * scsi_host_add() nor scsi_host_remove() has been called.
 332                  * This avoids that the memory allocated for the shost_dev
 333                  * name is leaked.
 334                  */
 335                 kfree(dev_name(&shost->shost_dev));
 336         }
 337 
 338         if (shost->tag_set.tags)
 339                 scsi_mq_destroy_tags(shost);
 340 
 341         kfree(shost->shost_data);
 342 
 343         ida_simple_remove(&host_index_ida, shost->host_no);
 344 
 345         if (parent)
 346                 put_device(parent);
 347         kfree(shost);
 348 }
 349 
 350 static struct device_type scsi_host_type = {
 351         .name =         "scsi_host",
 352         .release =      scsi_host_dev_release,
 353 };
 354 
 355 /**
 356  * scsi_host_alloc - register a scsi host adapter instance.
 357  * @sht:        pointer to scsi host template
 358  * @privsize:   extra bytes to allocate for driver
 359  *
 360  * Note:
 361  *      Allocate a new Scsi_Host and perform basic initialization.
 362  *      The host is not published to the scsi midlayer until scsi_add_host
 363  *      is called.
 364  *
 365  * Return value:
 366  *      Pointer to a new Scsi_Host
 367  **/
 368 struct Scsi_Host *scsi_host_alloc(struct scsi_host_template *sht, int privsize)
 369 {
 370         struct Scsi_Host *shost;
 371         gfp_t gfp_mask = GFP_KERNEL;
 372         int index;
 373 
 374         if (sht->unchecked_isa_dma && privsize)
 375                 gfp_mask |= __GFP_DMA;
 376 
 377         shost = kzalloc(sizeof(struct Scsi_Host) + privsize, gfp_mask);
 378         if (!shost)
 379                 return NULL;
 380 
 381         shost->host_lock = &shost->default_lock;
 382         spin_lock_init(shost->host_lock);
 383         shost->shost_state = SHOST_CREATED;
 384         INIT_LIST_HEAD(&shost->__devices);
 385         INIT_LIST_HEAD(&shost->__targets);
 386         INIT_LIST_HEAD(&shost->eh_cmd_q);
 387         INIT_LIST_HEAD(&shost->starved_list);
 388         init_waitqueue_head(&shost->host_wait);
 389         mutex_init(&shost->scan_mutex);
 390 
 391         index = ida_simple_get(&host_index_ida, 0, 0, GFP_KERNEL);
 392         if (index < 0)
 393                 goto fail_kfree;
 394         shost->host_no = index;
 395 
 396         shost->dma_channel = 0xff;
 397 
 398         /* These three are default values which can be overridden */
 399         shost->max_channel = 0;
 400         shost->max_id = 8;
 401         shost->max_lun = 8;
 402 
 403         /* Give each shost a default transportt */
 404         shost->transportt = &blank_transport_template;
 405 
 406         /*
 407          * All drivers right now should be able to handle 12 byte
 408          * commands.  Every so often there are requests for 16 byte
 409          * commands, but individual low-level drivers need to certify that
 410          * they actually do something sensible with such commands.
 411          */
 412         shost->max_cmd_len = 12;
 413         shost->hostt = sht;
 414         shost->this_id = sht->this_id;
 415         shost->can_queue = sht->can_queue;
 416         shost->sg_tablesize = sht->sg_tablesize;
 417         shost->sg_prot_tablesize = sht->sg_prot_tablesize;
 418         shost->cmd_per_lun = sht->cmd_per_lun;
 419         shost->unchecked_isa_dma = sht->unchecked_isa_dma;
 420         shost->no_write_same = sht->no_write_same;
 421 
 422         if (shost_eh_deadline == -1 || !sht->eh_host_reset_handler)
 423                 shost->eh_deadline = -1;
 424         else if ((ulong) shost_eh_deadline * HZ > INT_MAX) {
 425                 shost_printk(KERN_WARNING, shost,
 426                              "eh_deadline %u too large, setting to %u\n",
 427                              shost_eh_deadline, INT_MAX / HZ);
 428                 shost->eh_deadline = INT_MAX;
 429         } else
 430                 shost->eh_deadline = shost_eh_deadline * HZ;
 431 
 432         if (sht->supported_mode == MODE_UNKNOWN)
 433                 /* means we didn't set it ... default to INITIATOR */
 434                 shost->active_mode = MODE_INITIATOR;
 435         else
 436                 shost->active_mode = sht->supported_mode;
 437 
 438         if (sht->max_host_blocked)
 439                 shost->max_host_blocked = sht->max_host_blocked;
 440         else
 441                 shost->max_host_blocked = SCSI_DEFAULT_HOST_BLOCKED;
 442 
 443         /*
 444          * If the driver imposes no hard sector transfer limit, start at
 445          * machine infinity initially.
 446          */
 447         if (sht->max_sectors)
 448                 shost->max_sectors = sht->max_sectors;
 449         else
 450                 shost->max_sectors = SCSI_DEFAULT_MAX_SECTORS;
 451 
 452         if (sht->max_segment_size)
 453                 shost->max_segment_size = sht->max_segment_size;
 454         else
 455                 shost->max_segment_size = BLK_MAX_SEGMENT_SIZE;
 456 
 457         /*
 458          * assume a 4GB boundary, if not set
 459          */
 460         if (sht->dma_boundary)
 461                 shost->dma_boundary = sht->dma_boundary;
 462         else
 463                 shost->dma_boundary = 0xffffffff;
 464 
 465         if (sht->virt_boundary_mask)
 466                 shost->virt_boundary_mask = sht->virt_boundary_mask;
 467 
 468         device_initialize(&shost->shost_gendev);
 469         dev_set_name(&shost->shost_gendev, "host%d", shost->host_no);
 470         shost->shost_gendev.bus = &scsi_bus_type;
 471         shost->shost_gendev.type = &scsi_host_type;
 472 
 473         device_initialize(&shost->shost_dev);
 474         shost->shost_dev.parent = &shost->shost_gendev;
 475         shost->shost_dev.class = &shost_class;
 476         dev_set_name(&shost->shost_dev, "host%d", shost->host_no);
 477         shost->shost_dev.groups = scsi_sysfs_shost_attr_groups;
 478 
 479         shost->ehandler = kthread_run(scsi_error_handler, shost,
 480                         "scsi_eh_%d", shost->host_no);
 481         if (IS_ERR(shost->ehandler)) {
 482                 shost_printk(KERN_WARNING, shost,
 483                         "error handler thread failed to spawn, error = %ld\n",
 484                         PTR_ERR(shost->ehandler));
 485                 goto fail_index_remove;
 486         }
 487 
 488         shost->tmf_work_q = alloc_workqueue("scsi_tmf_%d",
 489                                             WQ_UNBOUND | WQ_MEM_RECLAIM,
 490                                            1, shost->host_no);
 491         if (!shost->tmf_work_q) {
 492                 shost_printk(KERN_WARNING, shost,
 493                              "failed to create tmf workq\n");
 494                 goto fail_kthread;
 495         }
 496         scsi_proc_hostdir_add(shost->hostt);
 497         return shost;
 498 
 499  fail_kthread:
 500         kthread_stop(shost->ehandler);
 501  fail_index_remove:
 502         ida_simple_remove(&host_index_ida, shost->host_no);
 503  fail_kfree:
 504         kfree(shost);
 505         return NULL;
 506 }
 507 EXPORT_SYMBOL(scsi_host_alloc);
 508 
 509 static int __scsi_host_match(struct device *dev, const void *data)
 510 {
 511         struct Scsi_Host *p;
 512         const unsigned short *hostnum = data;
 513 
 514         p = class_to_shost(dev);
 515         return p->host_no == *hostnum;
 516 }
 517 
 518 /**
 519  * scsi_host_lookup - get a reference to a Scsi_Host by host no
 520  * @hostnum:    host number to locate
 521  *
 522  * Return value:
 523  *      A pointer to located Scsi_Host or NULL.
 524  *
 525  *      The caller must do a scsi_host_put() to drop the reference
 526  *      that scsi_host_get() took. The put_device() below dropped
 527  *      the reference from class_find_device().
 528  **/
 529 struct Scsi_Host *scsi_host_lookup(unsigned short hostnum)
 530 {
 531         struct device *cdev;
 532         struct Scsi_Host *shost = NULL;
 533 
 534         cdev = class_find_device(&shost_class, NULL, &hostnum,
 535                                  __scsi_host_match);
 536         if (cdev) {
 537                 shost = scsi_host_get(class_to_shost(cdev));
 538                 put_device(cdev);
 539         }
 540         return shost;
 541 }
 542 EXPORT_SYMBOL(scsi_host_lookup);
 543 
 544 /**
 545  * scsi_host_get - inc a Scsi_Host ref count
 546  * @shost:      Pointer to Scsi_Host to inc.
 547  **/
 548 struct Scsi_Host *scsi_host_get(struct Scsi_Host *shost)
 549 {
 550         if ((shost->shost_state == SHOST_DEL) ||
 551                 !get_device(&shost->shost_gendev))
 552                 return NULL;
 553         return shost;
 554 }
 555 EXPORT_SYMBOL(scsi_host_get);
 556 
 557 /**
 558  * scsi_host_busy - Return the host busy counter
 559  * @shost:      Pointer to Scsi_Host to inc.
 560  **/
 561 int scsi_host_busy(struct Scsi_Host *shost)
 562 {
 563         return atomic_read(&shost->host_busy);
 564 }
 565 EXPORT_SYMBOL(scsi_host_busy);
 566 
 567 /**
 568  * scsi_host_put - dec a Scsi_Host ref count
 569  * @shost:      Pointer to Scsi_Host to dec.
 570  **/
 571 void scsi_host_put(struct Scsi_Host *shost)
 572 {
 573         put_device(&shost->shost_gendev);
 574 }
 575 EXPORT_SYMBOL(scsi_host_put);
 576 
 577 int scsi_init_hosts(void)
 578 {
 579         return class_register(&shost_class);
 580 }
 581 
 582 void scsi_exit_hosts(void)
 583 {
 584         class_unregister(&shost_class);
 585         ida_destroy(&host_index_ida);
 586 }
 587 
 588 int scsi_is_host_device(const struct device *dev)
 589 {
 590         return dev->type == &scsi_host_type;
 591 }
 592 EXPORT_SYMBOL(scsi_is_host_device);
 593 
 594 /**
 595  * scsi_queue_work - Queue work to the Scsi_Host workqueue.
 596  * @shost:      Pointer to Scsi_Host.
 597  * @work:       Work to queue for execution.
 598  *
 599  * Return value:
 600  *      1 - work queued for execution
 601  *      0 - work is already queued
 602  *      -EINVAL - work queue doesn't exist
 603  **/
 604 int scsi_queue_work(struct Scsi_Host *shost, struct work_struct *work)
 605 {
 606         if (unlikely(!shost->work_q)) {
 607                 shost_printk(KERN_ERR, shost,
 608                         "ERROR: Scsi host '%s' attempted to queue scsi-work, "
 609                         "when no workqueue created.\n", shost->hostt->name);
 610                 dump_stack();
 611 
 612                 return -EINVAL;
 613         }
 614 
 615         return queue_work(shost->work_q, work);
 616 }
 617 EXPORT_SYMBOL_GPL(scsi_queue_work);
 618 
 619 /**
 620  * scsi_flush_work - Flush a Scsi_Host's workqueue.
 621  * @shost:      Pointer to Scsi_Host.
 622  **/
 623 void scsi_flush_work(struct Scsi_Host *shost)
 624 {
 625         if (!shost->work_q) {
 626                 shost_printk(KERN_ERR, shost,
 627                         "ERROR: Scsi host '%s' attempted to flush scsi-work, "
 628                         "when no workqueue created.\n", shost->hostt->name);
 629                 dump_stack();
 630                 return;
 631         }
 632 
 633         flush_workqueue(shost->work_q);
 634 }
 635 EXPORT_SYMBOL_GPL(scsi_flush_work);