drivers/scsi/hosts.c

   1 /*
   2  *  hosts.c Copyright (C) 1992 Drew Eckhardt
   3  *          Copyright (C) 1993, 1994, 1995 Eric Youngdale
   4  *          Copyright (C) 2002-2003 Christoph Hellwig
   5  *
   6  *  mid to lowlevel SCSI driver interface
   7  *      Initial versions: Drew Eckhardt
   8  *      Subsequent revisions: Eric Youngdale
   9  *
  10  *  <drew@colorado.edu>
  11  *
  12  *  Jiffies wrap fixes (host->resetting), 3 Dec 1998 Andrea Arcangeli
  13  *  Added QLOGIC QLA1280 SCSI controller kernel host support.
  14  *     August 4, 1999 Fred Lewis, Intel DuPont
  15  *
  16  *  Updated to reflect the new initialization scheme for the higher
  17  *  level of scsi drivers (sd/sr/st)
  18  *  September 17, 2000 Torben Mathiasen <tmm@image.dk>
  19  *
  20  *  Restructured scsi_host lists and associated functions.
  21  *  September 04, 2002 Mike Anderson (andmike@us.ibm.com)
  22  */
  23
  24 #include <linux/module.h>
  25 #include <linux/blkdev.h>
  26 #include <linux/kernel.h>
  27 #include <linux/slab.h>
  28 #include <linux/kthread.h>
  29 #include <linux/string.h>
  30 #include <linux/mm.h>
  31 #include <linux/init.h>
  32 #include <linux/completion.h>
  33 #include <linux/transport_class.h>
  34 #include <linux/platform_device.h>
  35 #include <linux/pm_runtime.h>
  36 #include <linux/idr.h>
  37 #include <scsi/scsi_device.h>
  38 #include <scsi/scsi_host.h>
  39 #include <scsi/scsi_transport.h>
  40
  41 #include "scsi_priv.h"
  42 #include "scsi_logging.h"
  43
  44
  45 static int shost_eh_deadline = -1;
  46
  47 module_param_named(eh_deadline, shost_eh_deadline, int, S_IRUGO|S_IWUSR);
  48 MODULE_PARM_DESC(eh_deadline,
  49                  "SCSI EH timeout in seconds (should be between 0 and 2^31-1)");
  50
  51 static DEFINE_IDA(host_index_ida);
  52
  53
  54 static void scsi_host_cls_release(struct device *dev)
  55 {
  56         put_device(&class_to_shost(dev)->shost_gendev);
  57 }
  58
  59 static struct class shost_class = {
  60         .name           = "scsi_host",
  61         .dev_release    = scsi_host_cls_release,
  62 };
  63
  64 /**
  65  *      scsi_host_set_state - Take the given host through the host state model.
  66  *      @shost: scsi host to change the state of.
  67  *      @state: state to change to.
  68  *
  69  *      Returns zero if unsuccessful or an error if the requested
  70  *      transition is illegal.
  71  **/
  72 int scsi_host_set_state(struct Scsi_Host *shost, enum scsi_host_state state)
  73 {
  74         enum scsi_host_state oldstate = shost->shost_state;
  75
  76         if (state == oldstate)
  77                 return 0;
  78
  79         switch (state) {
  80         case SHOST_CREATED:
  81                 /* There are no legal states that come back to
  82                  * created.  This is the manually initialised start
  83                  * state */
  84                 goto illegal;
  85
  86         case SHOST_RUNNING:
  87                 switch (oldstate) {
  88                 case SHOST_CREATED:
  89                 case SHOST_RECOVERY:
  90                         break;
  91                 default:
  92                         goto illegal;
  93                 }
  94                 break;
  95
  96         case SHOST_RECOVERY:
  97                 switch (oldstate) {
  98                 case SHOST_RUNNING:
  99                         break;
 100                 default:
 101                         goto illegal;
 102                 }
 103                 break;
 104
 105         case SHOST_CANCEL:
 106                 switch (oldstate) {
 107                 case SHOST_CREATED:
 108                 case SHOST_RUNNING:
 109                 case SHOST_CANCEL_RECOVERY:
 110                         break;
 111                 default:
 112                         goto illegal;
 113                 }
 114                 break;
 115
 116         case SHOST_DEL:
 117                 switch (oldstate) {
 118                 case SHOST_CANCEL:
 119                 case SHOST_DEL_RECOVERY:
 120                         break;
 121                 default:
 122                         goto illegal;
 123                 }
 124                 break;
 125
 126         case SHOST_CANCEL_RECOVERY:
 127                 switch (oldstate) {
 128                 case SHOST_CANCEL:
 129                 case SHOST_RECOVERY:
 130                         break;
 131                 default:
 132                         goto illegal;
 133                 }
 134                 break;
 135
 136         case SHOST_DEL_RECOVERY:
 137                 switch (oldstate) {
 138                 case SHOST_CANCEL_RECOVERY:
 139                         break;
 140                 default:
 141                         goto illegal;
 142                 }
 143                 break;
 144         }
 145         shost->shost_state = state;
 146         return 0;
 147
 148  illegal:
 149         SCSI_LOG_ERROR_RECOVERY(1,
 150                                 shost_printk(KERN_ERR, shost,
 151                                              "Illegal host state transition"
 152                                              "%s->%s\n",
 153                                              scsi_host_state_name(oldstate),
 154                                              scsi_host_state_name(state)));
 155         return -EINVAL;
 156 }
 157
 158 /**
 159  * scsi_remove_host - remove a scsi host
 160  * @shost:      a pointer to a scsi host to remove
 161  **/
 162 void scsi_remove_host(struct Scsi_Host *shost)
 163 {
 164         unsigned long flags;
 165
 166         mutex_lock(&shost->scan_mutex);
 167         spin_lock_irqsave(shost->host_lock, flags);
 168         if (scsi_host_set_state(shost, SHOST_CANCEL))
 169                 if (scsi_host_set_state(shost, SHOST_CANCEL_RECOVERY)) {
 170                         spin_unlock_irqrestore(shost->host_lock, flags);
 171                         mutex_unlock(&shost->scan_mutex);
 172                         return;
 173                 }
 174         spin_unlock_irqrestore(shost->host_lock, flags);
 175
 176         scsi_autopm_get_host(shost);
 177         flush_workqueue(shost->tmf_work_q);
 178         scsi_forget_host(shost);
 179         mutex_unlock(&shost->scan_mutex);
 180         scsi_proc_host_rm(shost);
 181
 182         spin_lock_irqsave(shost->host_lock, flags);
 183         if (scsi_host_set_state(shost, SHOST_DEL))
 184                 BUG_ON(scsi_host_set_state(shost, SHOST_DEL_RECOVERY));
 185         spin_unlock_irqrestore(shost->host_lock, flags);
 186
 187         transport_unregister_device(&shost->shost_gendev);
 188         device_unregister(&shost->shost_dev);
 189         device_del(&shost->shost_gendev);
 190 }
 191 EXPORT_SYMBOL(scsi_remove_host);
 192
 193 /**
 194  * scsi_add_host_with_dma - add a scsi host with dma device
 195  * @shost:      scsi host pointer to add
 196  * @dev:        a struct device of type scsi class
 197  * @dma_dev:    dma device for the host
 198  *
 199  * Note: You rarely need to worry about this unless you're in a
 200  * virtualised host environments, so use the simpler scsi_add_host()
 201  * function instead.
 202  *
 203  * Return value:
 204  *      0 on success / != 0 for error
 205  **/
 206 int scsi_add_host_with_dma(struct Scsi_Host *shost, struct device *dev,
 207                            struct device *dma_dev)
 208 {
 209         struct scsi_host_template *sht = shost->hostt;
 210         int error = -EINVAL;
 211
 212         shost_printk(KERN_INFO, shost, "%s\n",
 213                         sht->info ? sht->info(shost) : sht->name);
 214
 215         if (!shost->can_queue) {
 216                 shost_printk(KERN_ERR, shost,
 217                              "can_queue = 0 no longer supported\n");
 218                 goto fail;
 219         }
 220
 221         error = scsi_init_sense_cache(shost);
 222         if (error)
 223                 goto fail;
 224
 225         error = scsi_mq_setup_tags(shost);
 226         if (error)
 227                 goto fail;
 228
 229         if (!shost->shost_gendev.parent)
 230                 shost->shost_gendev.parent = dev ? dev : &platform_bus;
 231         if (!dma_dev)
 232                 dma_dev = shost->shost_gendev.parent;
 233
 234         shost->dma_dev = dma_dev;
 235
 236         /*
 237          * Increase usage count temporarily here so that calling
 238          * scsi_autopm_put_host() will trigger runtime idle if there is
 239          * nothing else preventing suspending the device.
 240          */
 241         pm_runtime_get_noresume(&shost->shost_gendev);
 242         pm_runtime_set_active(&shost->shost_gendev);
 243         pm_runtime_enable(&shost->shost_gendev);
 244         device_enable_async_suspend(&shost->shost_gendev);
 245
 246         error = device_add(&shost->shost_gendev);
 247         if (error)
 248                 goto out_disable_runtime_pm;
 249
 250         scsi_host_set_state(shost, SHOST_RUNNING);
 251         get_device(shost->shost_gendev.parent);
 252
 253         device_enable_async_suspend(&shost->shost_dev);
 254
 255         error = device_add(&shost->shost_dev);
 256         if (error)
 257                 goto out_del_gendev;
 258
 259         get_device(&shost->shost_gendev);
 260
 261         if (shost->transportt->host_size) {
 262                 shost->shost_data = kzalloc(shost->transportt->host_size,
 263                                          GFP_KERNEL);
 264                 if (shost->shost_data == NULL) {
 265                         error = -ENOMEM;
 266                         goto out_del_dev;
 267                 }
 268         }
 269
 270         if (shost->transportt->create_work_queue) {
 271                 snprintf(shost->work_q_name, sizeof(shost->work_q_name),
 272                          "scsi_wq_%d", shost->host_no);
 273                 shost->work_q = create_singlethread_workqueue(
 274                                         shost->work_q_name);
 275                 if (!shost->work_q) {
 276                         error = -EINVAL;
 277                         goto out_free_shost_data;
 278                 }
 279         }
 280
 281         error = scsi_sysfs_add_host(shost);
 282         if (error)
 283                 goto out_destroy_host;
 284
 285         scsi_proc_host_add(shost);
 286         scsi_autopm_put_host(shost);
 287         return error;
 288
 289  out_destroy_host:
 290         if (shost->work_q)
 291                 destroy_workqueue(shost->work_q);
 292  out_free_shost_data:
 293         kfree(shost->shost_data);
 294  out_del_dev:
 295         device_del(&shost->shost_dev);
 296  out_del_gendev:
 297         device_del(&shost->shost_gendev);
 298  out_disable_runtime_pm:
 299         device_disable_async_suspend(&shost->shost_gendev);
 300         pm_runtime_disable(&shost->shost_gendev);
 301         pm_runtime_set_suspended(&shost->shost_gendev);
 302         pm_runtime_put_noidle(&shost->shost_gendev);
 303         scsi_mq_destroy_tags(shost);
 304  fail:
 305         return error;
 306 }
 307 EXPORT_SYMBOL(scsi_add_host_with_dma);
 308
 309 static void scsi_host_dev_release(struct device *dev)
 310 {
 311         struct Scsi_Host *shost = dev_to_shost(dev);
 312         struct device *parent = dev->parent;
 313
 314         scsi_proc_hostdir_rm(shost->hostt);
 315
 316         /* Wait for functions invoked through call_rcu(&shost->rcu, ...) */
 317         rcu_barrier();
 318
 319         if (shost->tmf_work_q)
 320                 destroy_workqueue(shost->tmf_work_q);
 321         if (shost->ehandler)
 322                 kthread_stop(shost->ehandler);
 323         if (shost->work_q)
 324                 destroy_workqueue(shost->work_q);
 325
 326         if (shost->shost_state == SHOST_CREATED) {
 327                 /*
 328                  * Free the shost_dev device name here if scsi_host_alloc()
 329                  * and scsi_host_put() have been called but neither
 330                  * scsi_host_add() nor scsi_host_remove() has been called.
 331                  * This avoids that the memory allocated for the shost_dev
 332                  * name is leaked.
 333                  */
 334                 kfree(dev_name(&shost->shost_dev));
 335         }
 336
 337         if (shost->tag_set.tags)
 338                 scsi_mq_destroy_tags(shost);
 339
 340         kfree(shost->shost_data);
 341
 342         ida_simple_remove(&host_index_ida, shost->host_no);
 343
 344         if (parent)
 345                 put_device(parent);
 346         kfree(shost);
 347 }
 348
 349 static struct device_type scsi_host_type = {
 350         .name =         "scsi_host",
 351         .release =      scsi_host_dev_release,
 352 };
 353
 354 /**
 355  * scsi_host_alloc - register a scsi host adapter instance.
 356  * @sht:        pointer to scsi host template
 357  * @privsize:   extra bytes to allocate for driver
 358  *
 359  * Note:
 360  *      Allocate a new Scsi_Host and perform basic initialization.
 361  *      The host is not published to the scsi midlayer until scsi_add_host
 362  *      is called.
 363  *
 364  * Return value:
 365  *      Pointer to a new Scsi_Host
 366  **/
 367 struct Scsi_Host *scsi_host_alloc(struct scsi_host_template *sht, int privsize)
 368 {
 369         struct Scsi_Host *shost;
 370         gfp_t gfp_mask = GFP_KERNEL;
 371         int index;
 372
 373         if (sht->unchecked_isa_dma && privsize)
 374                 gfp_mask |= __GFP_DMA;
 375
 376         shost = kzalloc(sizeof(struct Scsi_Host) + privsize, gfp_mask);
 377         if (!shost)
 378                 return NULL;
 379
 380         shost->host_lock = &shost->default_lock;
 381         spin_lock_init(shost->host_lock);
 382         shost->shost_state = SHOST_CREATED;
 383         INIT_LIST_HEAD(&shost->__devices);
 384         INIT_LIST_HEAD(&shost->__targets);
 385         INIT_LIST_HEAD(&shost->eh_cmd_q);
 386         INIT_LIST_HEAD(&shost->starved_list);
 387         init_waitqueue_head(&shost->host_wait);
 388         mutex_init(&shost->scan_mutex);
 389
 390         index = ida_simple_get(&host_index_ida, 0, 0, GFP_KERNEL);
 391         if (index < 0)
 392                 goto fail_kfree;
 393         shost->host_no = index;
 394
 395         shost->dma_channel = 0xff;
 396
 397         /* These three are default values which can be overridden */
 398         shost->max_channel = 0;
 399         shost->max_id = 8;
 400         shost->max_lun = 8;
 401
 402         /* Give each shost a default transportt */
 403         shost->transportt = &blank_transport_template;
 404
 405         /*
 406          * All drivers right now should be able to handle 12 byte
 407          * commands.  Every so often there are requests for 16 byte
 408          * commands, but individual low-level drivers need to certify that
 409          * they actually do something sensible with such commands.
 410          */
 411         shost->max_cmd_len = 12;
 412         shost->hostt = sht;
 413         shost->this_id = sht->this_id;
 414         shost->can_queue = sht->can_queue;
 415         shost->sg_tablesize = sht->sg_tablesize;
 416         shost->sg_prot_tablesize = sht->sg_prot_tablesize;
 417         shost->cmd_per_lun = sht->cmd_per_lun;
 418         shost->unchecked_isa_dma = sht->unchecked_isa_dma;
 419         shost->no_write_same = sht->no_write_same;
 420
 421         if (shost_eh_deadline == -1 || !sht->eh_host_reset_handler)
 422                 shost->eh_deadline = -1;
 423         else if ((ulong) shost_eh_deadline * HZ > INT_MAX) {
 424                 shost_printk(KERN_WARNING, shost,
 425                              "eh_deadline %u too large, setting to %u\n",
 426                              shost_eh_deadline, INT_MAX / HZ);
 427                 shost->eh_deadline = INT_MAX;
 428         } else
 429                 shost->eh_deadline = shost_eh_deadline * HZ;
 430
 431         if (sht->supported_mode == MODE_UNKNOWN)
 432                 /* means we didn't set it ... default to INITIATOR */
 433                 shost->active_mode = MODE_INITIATOR;
 434         else
 435                 shost->active_mode = sht->supported_mode;
 436
 437         if (sht->max_host_blocked)
 438                 shost->max_host_blocked = sht->max_host_blocked;
 439         else
 440                 shost->max_host_blocked = SCSI_DEFAULT_HOST_BLOCKED;
 441
 442         /*
 443          * If the driver imposes no hard sector transfer limit, start at
 444          * machine infinity initially.
 445          */
 446         if (sht->max_sectors)
 447                 shost->max_sectors = sht->max_sectors;
 448         else
 449                 shost->max_sectors = SCSI_DEFAULT_MAX_SECTORS;
 450
 451         if (sht->max_segment_size)
 452                 shost->max_segment_size = sht->max_segment_size;
 453         else
 454                 shost->max_segment_size = BLK_MAX_SEGMENT_SIZE;
 455
 456         /*
 457          * assume a 4GB boundary, if not set
 458          */
 459         if (sht->dma_boundary)
 460                 shost->dma_boundary = sht->dma_boundary;
 461         else
 462                 shost->dma_boundary = 0xffffffff;
 463
 464         device_initialize(&shost->shost_gendev);
 465         dev_set_name(&shost->shost_gendev, "host%d", shost->host_no);
 466         shost->shost_gendev.bus = &scsi_bus_type;
 467         shost->shost_gendev.type = &scsi_host_type;
 468
 469         device_initialize(&shost->shost_dev);
 470         shost->shost_dev.parent = &shost->shost_gendev;
 471         shost->shost_dev.class = &shost_class;
 472         dev_set_name(&shost->shost_dev, "host%d", shost->host_no);
 473         shost->shost_dev.groups = scsi_sysfs_shost_attr_groups;
 474
 475         shost->ehandler = kthread_run(scsi_error_handler, shost,
 476                         "scsi_eh_%d", shost->host_no);
 477         if (IS_ERR(shost->ehandler)) {
 478                 shost_printk(KERN_WARNING, shost,
 479                         "error handler thread failed to spawn, error = %ld\n",
 480                         PTR_ERR(shost->ehandler));
 481                 goto fail_index_remove;
 482         }
 483
 484         shost->tmf_work_q = alloc_workqueue("scsi_tmf_%d",
 485                                             WQ_UNBOUND | WQ_MEM_RECLAIM,
 486                                            1, shost->host_no);
 487         if (!shost->tmf_work_q) {
 488                 shost_printk(KERN_WARNING, shost,
 489                              "failed to create tmf workq\n");
 490                 goto fail_kthread;
 491         }
 492         scsi_proc_hostdir_add(shost->hostt);
 493         return shost;
 494
 495  fail_kthread:
 496         kthread_stop(shost->ehandler);
 497  fail_index_remove:
 498         ida_simple_remove(&host_index_ida, shost->host_no);
 499  fail_kfree:
 500         kfree(shost);
 501         return NULL;
 502 }
 503 EXPORT_SYMBOL(scsi_host_alloc);
 504
 505 static int __scsi_host_match(struct device *dev, const void *data)
 506 {
 507         struct Scsi_Host *p;
 508         const unsigned short *hostnum = data;
 509
 510         p = class_to_shost(dev);
 511         return p->host_no == *hostnum;
 512 }
 513
 514 /**
 515  * scsi_host_lookup - get a reference to a Scsi_Host by host no
 516  * @hostnum:    host number to locate
 517  *
 518  * Return value:
 519  *      A pointer to located Scsi_Host or NULL.
 520  *
 521  *      The caller must do a scsi_host_put() to drop the reference
 522  *      that scsi_host_get() took. The put_device() below dropped
 523  *      the reference from class_find_device().
 524  **/
 525 struct Scsi_Host *scsi_host_lookup(unsigned short hostnum)
 526 {
 527         struct device *cdev;
 528         struct Scsi_Host *shost = NULL;
 529
 530         cdev = class_find_device(&shost_class, NULL, &hostnum,
 531                                  __scsi_host_match);
 532         if (cdev) {
 533                 shost = scsi_host_get(class_to_shost(cdev));
 534                 put_device(cdev);
 535         }
 536         return shost;
 537 }
 538 EXPORT_SYMBOL(scsi_host_lookup);
 539
 540 /**
 541  * scsi_host_get - inc a Scsi_Host ref count
 542  * @shost:      Pointer to Scsi_Host to inc.
 543  **/
 544 struct Scsi_Host *scsi_host_get(struct Scsi_Host *shost)
 545 {
 546         if ((shost->shost_state == SHOST_DEL) ||
 547                 !get_device(&shost->shost_gendev))
 548                 return NULL;
 549         return shost;
 550 }
 551 EXPORT_SYMBOL(scsi_host_get);
 552
 553 /**
 554  * scsi_host_busy - Return the host busy counter
 555  * @shost:      Pointer to Scsi_Host to inc.
 556  **/
 557 int scsi_host_busy(struct Scsi_Host *shost)
 558 {
 559         return atomic_read(&shost->host_busy);
 560 }
 561 EXPORT_SYMBOL(scsi_host_busy);
 562
 563 /**
 564  * scsi_host_put - dec a Scsi_Host ref count
 565  * @shost:      Pointer to Scsi_Host to dec.
 566  **/
 567 void scsi_host_put(struct Scsi_Host *shost)
 568 {
 569         put_device(&shost->shost_gendev);
 570 }
 571 EXPORT_SYMBOL(scsi_host_put);
 572
 573 int scsi_init_hosts(void)
 574 {
 575         return class_register(&shost_class);
 576 }
 577
 578 void scsi_exit_hosts(void)
 579 {
 580         class_unregister(&shost_class);
 581         ida_destroy(&host_index_ida);
 582 }
 583
 584 int scsi_is_host_device(const struct device *dev)
 585 {
 586         return dev->type == &scsi_host_type;
 587 }
 588 EXPORT_SYMBOL(scsi_is_host_device);
 589
 590 /**
 591  * scsi_queue_work - Queue work to the Scsi_Host workqueue.
 592  * @shost:      Pointer to Scsi_Host.
 593  * @work:       Work to queue for execution.
 594  *
 595  * Return value:
 596  *      1 - work queued for execution
 597  *      0 - work is already queued
 598  *      -EINVAL - work queue doesn't exist
 599  **/
 600 int scsi_queue_work(struct Scsi_Host *shost, struct work_struct *work)
 601 {
 602         if (unlikely(!shost->work_q)) {
 603                 shost_printk(KERN_ERR, shost,
 604                         "ERROR: Scsi host '%s' attempted to queue scsi-work, "
 605                         "when no workqueue created.\n", shost->hostt->name);
 606                 dump_stack();
 607
 608                 return -EINVAL;
 609         }
 610
 611         return queue_work(shost->work_q, work);
 612 }
 613 EXPORT_SYMBOL_GPL(scsi_queue_work);
 614
 615 /**
 616  * scsi_flush_work - Flush a Scsi_Host's workqueue.
 617  * @shost:      Pointer to Scsi_Host.
 618  **/
 619 void scsi_flush_work(struct Scsi_Host *shost)
 620 {
 621         if (!shost->work_q) {
 622                 shost_printk(KERN_ERR, shost,
 623                         "ERROR: Scsi host '%s' attempted to flush scsi-work, "
 624                         "when no workqueue created.\n", shost->hostt->name);
 625                 dump_stack();
 626                 return;
 627         }
 628
 629         flush_workqueue(shost->work_q);
 630 }
 631 EXPORT_SYMBOL_GPL(scsi_flush_work);