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         scsi_proc_hostdir_rm(shost->hostt);
 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         if (shost_use_blk_mq(shost)) {
 231                 error = scsi_mq_setup_tags(shost);
 232                 if (error)
 233                         goto fail;
 234         } else {
 235                 shost->bqt = blk_init_tags(shost->can_queue,
 236                                 shost->hostt->tag_alloc_policy);
 237                 if (!shost->bqt) {
 238                         error = -ENOMEM;
 239                         goto fail;
 240                 }
 241         }
 242
 243         if (!shost->shost_gendev.parent)
 244                 shost->shost_gendev.parent = dev ? dev : &platform_bus;
 245         if (!dma_dev)
 246                 dma_dev = shost->shost_gendev.parent;
 247
 248         shost->dma_dev = dma_dev;
 249
 250         /*
 251          * Increase usage count temporarily here so that calling
 252          * scsi_autopm_put_host() will trigger runtime idle if there is
 253          * nothing else preventing suspending the device.
 254          */
 255         pm_runtime_get_noresume(&shost->shost_gendev);
 256         pm_runtime_set_active(&shost->shost_gendev);
 257         pm_runtime_enable(&shost->shost_gendev);
 258         device_enable_async_suspend(&shost->shost_gendev);
 259
 260         error = device_add(&shost->shost_gendev);
 261         if (error)
 262                 goto out_disable_runtime_pm;
 263
 264         scsi_host_set_state(shost, SHOST_RUNNING);
 265         get_device(shost->shost_gendev.parent);
 266
 267         device_enable_async_suspend(&shost->shost_dev);
 268
 269         get_device(&shost->shost_gendev);
 270         error = device_add(&shost->shost_dev);
 271         if (error)
 272                 goto out_del_gendev;
 273
 274         if (shost->transportt->host_size) {
 275                 shost->shost_data = kzalloc(shost->transportt->host_size,
 276                                          GFP_KERNEL);
 277                 if (shost->shost_data == NULL) {
 278                         error = -ENOMEM;
 279                         goto out_del_dev;
 280                 }
 281         }
 282
 283         if (shost->transportt->create_work_queue) {
 284                 snprintf(shost->work_q_name, sizeof(shost->work_q_name),
 285                          "scsi_wq_%d", shost->host_no);
 286                 shost->work_q = create_singlethread_workqueue(
 287                                         shost->work_q_name);
 288                 if (!shost->work_q) {
 289                         error = -EINVAL;
 290                         goto out_free_shost_data;
 291                 }
 292         }
 293
 294         error = scsi_sysfs_add_host(shost);
 295         if (error)
 296                 goto out_destroy_host;
 297
 298         scsi_proc_host_add(shost);
 299         scsi_autopm_put_host(shost);
 300         return error;
 301
 302  out_destroy_host:
 303         if (shost->work_q)
 304                 destroy_workqueue(shost->work_q);
 305  out_free_shost_data:
 306         kfree(shost->shost_data);
 307  out_del_dev:
 308         device_del(&shost->shost_dev);
 309  out_del_gendev:
 310         /*
 311          * Host state is SHOST_RUNNING so we have to explicitly release
 312          * ->shost_dev.
 313          */
 314         put_device(&shost->shost_dev);
 315         device_del(&shost->shost_gendev);
 316  out_disable_runtime_pm:
 317         device_disable_async_suspend(&shost->shost_gendev);
 318         pm_runtime_disable(&shost->shost_gendev);
 319         pm_runtime_set_suspended(&shost->shost_gendev);
 320         pm_runtime_put_noidle(&shost->shost_gendev);
 321         if (shost_use_blk_mq(shost))
 322                 scsi_mq_destroy_tags(shost);
 323  fail:
 324         return error;
 325 }
 326 EXPORT_SYMBOL(scsi_add_host_with_dma);
 327
 328 static void scsi_host_dev_release(struct device *dev)
 329 {
 330         struct Scsi_Host *shost = dev_to_shost(dev);
 331         struct device *parent = dev->parent;
 332
 333         /* In case scsi_remove_host() has not been called. */
 334         scsi_proc_hostdir_rm(shost->hostt);
 335
 336         /* Wait for functions invoked through call_rcu(&shost->rcu, ...) */
 337         rcu_barrier();
 338
 339         if (shost->tmf_work_q)
 340                 destroy_workqueue(shost->tmf_work_q);
 341         if (shost->ehandler)
 342                 kthread_stop(shost->ehandler);
 343         if (shost->work_q)
 344                 destroy_workqueue(shost->work_q);
 345
 346         if (shost->shost_state == SHOST_CREATED) {
 347                 /*
 348                  * Free the shost_dev device name here if scsi_host_alloc()
 349                  * and scsi_host_put() have been called but neither
 350                  * scsi_host_add() nor scsi_host_remove() has been called.
 351                  * This avoids that the memory allocated for the shost_dev
 352                  * name is leaked.
 353                  */
 354                 kfree(dev_name(&shost->shost_dev));
 355         }
 356
 357         if (shost_use_blk_mq(shost)) {
 358                 if (shost->tag_set.tags)
 359                         scsi_mq_destroy_tags(shost);
 360         } else {
 361                 if (shost->bqt)
 362                         blk_free_tags(shost->bqt);
 363         }
 364
 365         kfree(shost->shost_data);
 366
 367         ida_simple_remove(&host_index_ida, shost->host_no);
 368
 369         if (shost->shost_state != SHOST_CREATED)
 370                 put_device(parent);
 371         kfree(shost);
 372 }
 373
 374 static struct device_type scsi_host_type = {
 375         .name =         "scsi_host",
 376         .release =      scsi_host_dev_release,
 377 };
 378
 379 /**
 380  * scsi_host_alloc - register a scsi host adapter instance.
 381  * @sht:        pointer to scsi host template
 382  * @privsize:   extra bytes to allocate for driver
 383  *
 384  * Note:
 385  *      Allocate a new Scsi_Host and perform basic initialization.
 386  *      The host is not published to the scsi midlayer until scsi_add_host
 387  *      is called.
 388  *
 389  * Return value:
 390  *      Pointer to a new Scsi_Host
 391  **/
 392 struct Scsi_Host *scsi_host_alloc(struct scsi_host_template *sht, int privsize)
 393 {
 394         struct Scsi_Host *shost;
 395         gfp_t gfp_mask = GFP_KERNEL;
 396         int index;
 397
 398         if (sht->unchecked_isa_dma && privsize)
 399                 gfp_mask |= __GFP_DMA;
 400
 401         shost = kzalloc(sizeof(struct Scsi_Host) + privsize, gfp_mask);
 402         if (!shost)
 403                 return NULL;
 404
 405         shost->host_lock = &shost->default_lock;
 406         spin_lock_init(shost->host_lock);
 407         shost->shost_state = SHOST_CREATED;
 408         INIT_LIST_HEAD(&shost->__devices);
 409         INIT_LIST_HEAD(&shost->__targets);
 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_simple_get(&host_index_ida, 0, 0, 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->unchecked_isa_dma = sht->unchecked_isa_dma;
 446         shost->use_clustering = sht->use_clustering;
 447         shost->no_write_same = sht->no_write_same;
 448
 449         if (shost_eh_deadline == -1 || !sht->eh_host_reset_handler)
 450                 shost->eh_deadline = -1;
 451         else if ((ulong) shost_eh_deadline * HZ > INT_MAX) {
 452                 shost_printk(KERN_WARNING, shost,
 453                              "eh_deadline %u too large, setting to %u\n",
 454                              shost_eh_deadline, INT_MAX / HZ);
 455                 shost->eh_deadline = INT_MAX;
 456         } else
 457                 shost->eh_deadline = shost_eh_deadline * HZ;
 458
 459         if (sht->supported_mode == MODE_UNKNOWN)
 460                 /* means we didn't set it ... default to INITIATOR */
 461                 shost->active_mode = MODE_INITIATOR;
 462         else
 463                 shost->active_mode = sht->supported_mode;
 464
 465         if (sht->max_host_blocked)
 466                 shost->max_host_blocked = sht->max_host_blocked;
 467         else
 468                 shost->max_host_blocked = SCSI_DEFAULT_HOST_BLOCKED;
 469
 470         /*
 471          * If the driver imposes no hard sector transfer limit, start at
 472          * machine infinity initially.
 473          */
 474         if (sht->max_sectors)
 475                 shost->max_sectors = sht->max_sectors;
 476         else
 477                 shost->max_sectors = SCSI_DEFAULT_MAX_SECTORS;
 478
 479         /*
 480          * assume a 4GB boundary, if not set
 481          */
 482         if (sht->dma_boundary)
 483                 shost->dma_boundary = sht->dma_boundary;
 484         else
 485                 shost->dma_boundary = 0xffffffff;
 486
 487         shost->use_blk_mq = scsi_use_blk_mq || shost->hostt->force_blk_mq;
 488
 489         device_initialize(&shost->shost_gendev);
 490         dev_set_name(&shost->shost_gendev, "host%d", shost->host_no);
 491         shost->shost_gendev.bus = &scsi_bus_type;
 492         shost->shost_gendev.type = &scsi_host_type;
 493
 494         device_initialize(&shost->shost_dev);
 495         shost->shost_dev.parent = &shost->shost_gendev;
 496         shost->shost_dev.class = &shost_class;
 497         dev_set_name(&shost->shost_dev, "host%d", shost->host_no);
 498         shost->shost_dev.groups = scsi_sysfs_shost_attr_groups;
 499
 500         shost->ehandler = kthread_run(scsi_error_handler, shost,
 501                         "scsi_eh_%d", shost->host_no);
 502         if (IS_ERR(shost->ehandler)) {
 503                 shost_printk(KERN_WARNING, shost,
 504                         "error handler thread failed to spawn, error = %ld\n",
 505                         PTR_ERR(shost->ehandler));
 506                 shost->ehandler = NULL;
 507                 goto fail;
 508         }
 509
 510         shost->tmf_work_q = alloc_workqueue("scsi_tmf_%d",
 511                                             WQ_UNBOUND | WQ_MEM_RECLAIM,
 512                                            1, shost->host_no);
 513         if (!shost->tmf_work_q) {
 514                 shost_printk(KERN_WARNING, shost,
 515                              "failed to create tmf workq\n");
 516                 goto fail;
 517         }
 518         scsi_proc_hostdir_add(shost->hostt);
 519         return shost;
 520  fail:
 521         /*
 522          * Host state is still SHOST_CREATED and that is enough to release
 523          * ->shost_gendev. scsi_host_dev_release() will free
 524          * dev_name(&shost->shost_dev).
 525          */
 526         put_device(&shost->shost_gendev);
 527
 528         return NULL;
 529 }
 530 EXPORT_SYMBOL(scsi_host_alloc);
 531
 532 static int __scsi_host_match(struct device *dev, const void *data)
 533 {
 534         struct Scsi_Host *p;
 535         const unsigned short *hostnum = data;
 536
 537         p = class_to_shost(dev);
 538         return p->host_no == *hostnum;
 539 }
 540
 541 /**
 542  * scsi_host_lookup - get a reference to a Scsi_Host by host no
 543  * @hostnum:    host number to locate
 544  *
 545  * Return value:
 546  *      A pointer to located Scsi_Host or NULL.
 547  *
 548  *      The caller must do a scsi_host_put() to drop the reference
 549  *      that scsi_host_get() took. The put_device() below dropped
 550  *      the reference from class_find_device().
 551  **/
 552 struct Scsi_Host *scsi_host_lookup(unsigned short hostnum)
 553 {
 554         struct device *cdev;
 555         struct Scsi_Host *shost = NULL;
 556
 557         cdev = class_find_device(&shost_class, NULL, &hostnum,
 558                                  __scsi_host_match);
 559         if (cdev) {
 560                 shost = scsi_host_get(class_to_shost(cdev));
 561                 put_device(cdev);
 562         }
 563         return shost;
 564 }
 565 EXPORT_SYMBOL(scsi_host_lookup);
 566
 567 /**
 568  * scsi_host_get - inc a Scsi_Host ref count
 569  * @shost:      Pointer to Scsi_Host to inc.
 570  **/
 571 struct Scsi_Host *scsi_host_get(struct Scsi_Host *shost)
 572 {
 573         if ((shost->shost_state == SHOST_DEL) ||
 574                 !get_device(&shost->shost_gendev))
 575                 return NULL;
 576         return shost;
 577 }
 578 EXPORT_SYMBOL(scsi_host_get);
 579
 580 /**
 581  * scsi_host_busy - Return the host busy counter
 582  * @shost:      Pointer to Scsi_Host to inc.
 583  **/
 584 int scsi_host_busy(struct Scsi_Host *shost)
 585 {
 586         return atomic_read(&shost->host_busy);
 587 }
 588 EXPORT_SYMBOL(scsi_host_busy);
 589
 590 /**
 591  * scsi_host_put - dec a Scsi_Host ref count
 592  * @shost:      Pointer to Scsi_Host to dec.
 593  **/
 594 void scsi_host_put(struct Scsi_Host *shost)
 595 {
 596         put_device(&shost->shost_gendev);
 597 }
 598 EXPORT_SYMBOL(scsi_host_put);
 599
 600 int scsi_init_hosts(void)
 601 {
 602         return class_register(&shost_class);
 603 }
 604
 605 void scsi_exit_hosts(void)
 606 {
 607         class_unregister(&shost_class);
 608         ida_destroy(&host_index_ida);
 609 }
 610
 611 int scsi_is_host_device(const struct device *dev)
 612 {
 613         return dev->type == &scsi_host_type;
 614 }
 615 EXPORT_SYMBOL(scsi_is_host_device);
 616
 617 /**
 618  * scsi_queue_work - Queue work to the Scsi_Host workqueue.
 619  * @shost:      Pointer to Scsi_Host.
 620  * @work:       Work to queue for execution.
 621  *
 622  * Return value:
 623  *      1 - work queued for execution
 624  *      0 - work is already queued
 625  *      -EINVAL - work queue doesn't exist
 626  **/
 627 int scsi_queue_work(struct Scsi_Host *shost, struct work_struct *work)
 628 {
 629         if (unlikely(!shost->work_q)) {
 630                 shost_printk(KERN_ERR, shost,
 631                         "ERROR: Scsi host '%s' attempted to queue scsi-work, "
 632                         "when no workqueue created.\n", shost->hostt->name);
 633                 dump_stack();
 634
 635                 return -EINVAL;
 636         }
 637
 638         return queue_work(shost->work_q, work);
 639 }
 640 EXPORT_SYMBOL_GPL(scsi_queue_work);
 641
 642 /**
 643  * scsi_flush_work - Flush a Scsi_Host's workqueue.
 644  * @shost:      Pointer to Scsi_Host.
 645  **/
 646 void scsi_flush_work(struct Scsi_Host *shost)
 647 {
 648         if (!shost->work_q) {
 649                 shost_printk(KERN_ERR, shost,
 650                         "ERROR: Scsi host '%s' attempted to flush scsi-work, "
 651                         "when no workqueue created.\n", shost->hostt->name);
 652                 dump_stack();
 653                 return;
 654         }
 655
 656         flush_workqueue(shost->work_q);
 657 }
 658 EXPORT_SYMBOL_GPL(scsi_flush_work);