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         /* Use min_t(int, ...) in case shost->can_queue exceeds SHRT_MAX */
 222         shost->cmd_per_lun = min_t(int, shost->cmd_per_lun,
 223                                    shost->can_queue);
 224
 225         error = scsi_init_sense_cache(shost);
 226         if (error)
 227                 goto fail;
 228
 229         if (shost_use_blk_mq(shost)) {
 230                 error = scsi_mq_setup_tags(shost);
 231                 if (error)
 232                         goto fail;
 233         } else {
 234                 shost->bqt = blk_init_tags(shost->can_queue,
 235                                 shost->hostt->tag_alloc_policy);
 236                 if (!shost->bqt) {
 237                         error = -ENOMEM;
 238                         goto fail;
 239                 }
 240         }
 241
 242         if (!shost->shost_gendev.parent)
 243                 shost->shost_gendev.parent = dev ? dev : &platform_bus;
 244         if (!dma_dev)
 245                 dma_dev = shost->shost_gendev.parent;
 246
 247         shost->dma_dev = dma_dev;
 248
 249         /*
 250          * Increase usage count temporarily here so that calling
 251          * scsi_autopm_put_host() will trigger runtime idle if there is
 252          * nothing else preventing suspending the device.
 253          */
 254         pm_runtime_get_noresume(&shost->shost_gendev);
 255         pm_runtime_set_active(&shost->shost_gendev);
 256         pm_runtime_enable(&shost->shost_gendev);
 257         device_enable_async_suspend(&shost->shost_gendev);
 258
 259         error = device_add(&shost->shost_gendev);
 260         if (error)
 261                 goto out_disable_runtime_pm;
 262
 263         scsi_host_set_state(shost, SHOST_RUNNING);
 264         get_device(shost->shost_gendev.parent);
 265
 266         device_enable_async_suspend(&shost->shost_dev);
 267
 268         get_device(&shost->shost_gendev);
 269         error = device_add(&shost->shost_dev);
 270         if (error)
 271                 goto out_del_gendev;
 272
 273         if (shost->transportt->host_size) {
 274                 shost->shost_data = kzalloc(shost->transportt->host_size,
 275                                          GFP_KERNEL);
 276                 if (shost->shost_data == NULL) {
 277                         error = -ENOMEM;
 278                         goto out_del_dev;
 279                 }
 280         }
 281
 282         if (shost->transportt->create_work_queue) {
 283                 snprintf(shost->work_q_name, sizeof(shost->work_q_name),
 284                          "scsi_wq_%d", shost->host_no);
 285                 shost->work_q = create_singlethread_workqueue(
 286                                         shost->work_q_name);
 287                 if (!shost->work_q) {
 288                         error = -EINVAL;
 289                         goto out_free_shost_data;
 290                 }
 291         }
 292
 293         error = scsi_sysfs_add_host(shost);
 294         if (error)
 295                 goto out_destroy_host;
 296
 297         scsi_proc_host_add(shost);
 298         scsi_autopm_put_host(shost);
 299         return error;
 300
 301  out_destroy_host:
 302         if (shost->work_q)
 303                 destroy_workqueue(shost->work_q);
 304  out_free_shost_data:
 305         kfree(shost->shost_data);
 306  out_del_dev:
 307         device_del(&shost->shost_dev);
 308  out_del_gendev:
 309         /*
 310          * Host state is SHOST_RUNNING so we have to explicitly release
 311          * ->shost_dev.
 312          */
 313         put_device(&shost->shost_dev);
 314         device_del(&shost->shost_gendev);
 315  out_disable_runtime_pm:
 316         device_disable_async_suspend(&shost->shost_gendev);
 317         pm_runtime_disable(&shost->shost_gendev);
 318         pm_runtime_set_suspended(&shost->shost_gendev);
 319         pm_runtime_put_noidle(&shost->shost_gendev);
 320         if (shost_use_blk_mq(shost))
 321                 scsi_mq_destroy_tags(shost);
 322  fail:
 323         return error;
 324 }
 325 EXPORT_SYMBOL(scsi_add_host_with_dma);
 326
 327 static void scsi_host_dev_release(struct device *dev)
 328 {
 329         struct Scsi_Host *shost = dev_to_shost(dev);
 330         struct device *parent = dev->parent;
 331
 332         scsi_proc_hostdir_rm(shost->hostt);
 333
 334         /* Wait for functions invoked through call_rcu(&shost->rcu, ...) */
 335         rcu_barrier();
 336
 337         if (shost->tmf_work_q)
 338                 destroy_workqueue(shost->tmf_work_q);
 339         if (shost->ehandler)
 340                 kthread_stop(shost->ehandler);
 341         if (shost->work_q)
 342                 destroy_workqueue(shost->work_q);
 343
 344         if (shost->shost_state == SHOST_CREATED) {
 345                 /*
 346                  * Free the shost_dev device name here if scsi_host_alloc()
 347                  * and scsi_host_put() have been called but neither
 348                  * scsi_host_add() nor scsi_host_remove() has been called.
 349                  * This avoids that the memory allocated for the shost_dev
 350                  * name is leaked.
 351                  */
 352                 kfree(dev_name(&shost->shost_dev));
 353         }
 354
 355         if (shost_use_blk_mq(shost)) {
 356                 if (shost->tag_set.tags)
 357                         scsi_mq_destroy_tags(shost);
 358         } else {
 359                 if (shost->bqt)
 360                         blk_free_tags(shost->bqt);
 361         }
 362
 363         kfree(shost->shost_data);
 364
 365         ida_simple_remove(&host_index_ida, shost->host_no);
 366
 367         if (shost->shost_state != SHOST_CREATED)
 368                 put_device(parent);
 369         kfree(shost);
 370 }
 371
 372 static struct device_type scsi_host_type = {
 373         .name =         "scsi_host",
 374         .release =      scsi_host_dev_release,
 375 };
 376
 377 /**
 378  * scsi_host_alloc - register a scsi host adapter instance.
 379  * @sht:        pointer to scsi host template
 380  * @privsize:   extra bytes to allocate for driver
 381  *
 382  * Note:
 383  *      Allocate a new Scsi_Host and perform basic initialization.
 384  *      The host is not published to the scsi midlayer until scsi_add_host
 385  *      is called.
 386  *
 387  * Return value:
 388  *      Pointer to a new Scsi_Host
 389  **/
 390 struct Scsi_Host *scsi_host_alloc(struct scsi_host_template *sht, int privsize)
 391 {
 392         struct Scsi_Host *shost;
 393         gfp_t gfp_mask = GFP_KERNEL;
 394         int index;
 395
 396         if (sht->unchecked_isa_dma && privsize)
 397                 gfp_mask |= __GFP_DMA;
 398
 399         shost = kzalloc(sizeof(struct Scsi_Host) + privsize, gfp_mask);
 400         if (!shost)
 401                 return NULL;
 402
 403         shost->host_lock = &shost->default_lock;
 404         spin_lock_init(shost->host_lock);
 405         shost->shost_state = SHOST_CREATED;
 406         INIT_LIST_HEAD(&shost->__devices);
 407         INIT_LIST_HEAD(&shost->__targets);
 408         INIT_LIST_HEAD(&shost->eh_cmd_q);
 409         INIT_LIST_HEAD(&shost->starved_list);
 410         init_waitqueue_head(&shost->host_wait);
 411         mutex_init(&shost->scan_mutex);
 412
 413         index = ida_simple_get(&host_index_ida, 0, 0, GFP_KERNEL);
 414         if (index < 0) {
 415                 kfree(shost);
 416                 return NULL;
 417         }
 418         shost->host_no = index;
 419
 420         shost->dma_channel = 0xff;
 421
 422         /* These three are default values which can be overridden */
 423         shost->max_channel = 0;
 424         shost->max_id = 8;
 425         shost->max_lun = 8;
 426
 427         /* Give each shost a default transportt */
 428         shost->transportt = &blank_transport_template;
 429
 430         /*
 431          * All drivers right now should be able to handle 12 byte
 432          * commands.  Every so often there are requests for 16 byte
 433          * commands, but individual low-level drivers need to certify that
 434          * they actually do something sensible with such commands.
 435          */
 436         shost->max_cmd_len = 12;
 437         shost->hostt = sht;
 438         shost->this_id = sht->this_id;
 439         shost->can_queue = sht->can_queue;
 440         shost->sg_tablesize = sht->sg_tablesize;
 441         shost->sg_prot_tablesize = sht->sg_prot_tablesize;
 442         shost->cmd_per_lun = sht->cmd_per_lun;
 443         shost->unchecked_isa_dma = sht->unchecked_isa_dma;
 444         shost->use_clustering = sht->use_clustering;
 445         shost->no_write_same = sht->no_write_same;
 446
 447         if (shost_eh_deadline == -1 || !sht->eh_host_reset_handler)
 448                 shost->eh_deadline = -1;
 449         else if ((ulong) shost_eh_deadline * HZ > INT_MAX) {
 450                 shost_printk(KERN_WARNING, shost,
 451                              "eh_deadline %u too large, setting to %u\n",
 452                              shost_eh_deadline, INT_MAX / HZ);
 453                 shost->eh_deadline = INT_MAX;
 454         } else
 455                 shost->eh_deadline = shost_eh_deadline * HZ;
 456
 457         if (sht->supported_mode == MODE_UNKNOWN)
 458                 /* means we didn't set it ... default to INITIATOR */
 459                 shost->active_mode = MODE_INITIATOR;
 460         else
 461                 shost->active_mode = sht->supported_mode;
 462
 463         if (sht->max_host_blocked)
 464                 shost->max_host_blocked = sht->max_host_blocked;
 465         else
 466                 shost->max_host_blocked = SCSI_DEFAULT_HOST_BLOCKED;
 467
 468         /*
 469          * If the driver imposes no hard sector transfer limit, start at
 470          * machine infinity initially.
 471          */
 472         if (sht->max_sectors)
 473                 shost->max_sectors = sht->max_sectors;
 474         else
 475                 shost->max_sectors = SCSI_DEFAULT_MAX_SECTORS;
 476
 477         /*
 478          * assume a 4GB boundary, if not set
 479          */
 480         if (sht->dma_boundary)
 481                 shost->dma_boundary = sht->dma_boundary;
 482         else
 483                 shost->dma_boundary = 0xffffffff;
 484
 485         shost->use_blk_mq = scsi_use_blk_mq || shost->hostt->force_blk_mq;
 486
 487         device_initialize(&shost->shost_gendev);
 488         dev_set_name(&shost->shost_gendev, "host%d", shost->host_no);
 489         shost->shost_gendev.bus = &scsi_bus_type;
 490         shost->shost_gendev.type = &scsi_host_type;
 491
 492         device_initialize(&shost->shost_dev);
 493         shost->shost_dev.parent = &shost->shost_gendev;
 494         shost->shost_dev.class = &shost_class;
 495         dev_set_name(&shost->shost_dev, "host%d", shost->host_no);
 496         shost->shost_dev.groups = scsi_sysfs_shost_attr_groups;
 497
 498         shost->ehandler = kthread_run(scsi_error_handler, shost,
 499                         "scsi_eh_%d", shost->host_no);
 500         if (IS_ERR(shost->ehandler)) {
 501                 shost_printk(KERN_WARNING, shost,
 502                         "error handler thread failed to spawn, error = %ld\n",
 503                         PTR_ERR(shost->ehandler));
 504                 shost->ehandler = NULL;
 505                 goto fail;
 506         }
 507
 508         shost->tmf_work_q = alloc_workqueue("scsi_tmf_%d",
 509                                             WQ_UNBOUND | WQ_MEM_RECLAIM,
 510                                            1, shost->host_no);
 511         if (!shost->tmf_work_q) {
 512                 shost_printk(KERN_WARNING, shost,
 513                              "failed to create tmf workq\n");
 514                 goto fail;
 515         }
 516         scsi_proc_hostdir_add(shost->hostt);
 517         return shost;
 518  fail:
 519         /*
 520          * Host state is still SHOST_CREATED and that is enough to release
 521          * ->shost_gendev. scsi_host_dev_release() will free
 522          * dev_name(&shost->shost_dev).
 523          */
 524         put_device(&shost->shost_gendev);
 525
 526         return NULL;
 527 }
 528 EXPORT_SYMBOL(scsi_host_alloc);
 529
 530 static int __scsi_host_match(struct device *dev, const void *data)
 531 {
 532         struct Scsi_Host *p;
 533         const unsigned short *hostnum = data;
 534
 535         p = class_to_shost(dev);
 536         return p->host_no == *hostnum;
 537 }
 538
 539 /**
 540  * scsi_host_lookup - get a reference to a Scsi_Host by host no
 541  * @hostnum:    host number to locate
 542  *
 543  * Return value:
 544  *      A pointer to located Scsi_Host or NULL.
 545  *
 546  *      The caller must do a scsi_host_put() to drop the reference
 547  *      that scsi_host_get() took. The put_device() below dropped
 548  *      the reference from class_find_device().
 549  **/
 550 struct Scsi_Host *scsi_host_lookup(unsigned short hostnum)
 551 {
 552         struct device *cdev;
 553         struct Scsi_Host *shost = NULL;
 554
 555         cdev = class_find_device(&shost_class, NULL, &hostnum,
 556                                  __scsi_host_match);
 557         if (cdev) {
 558                 shost = scsi_host_get(class_to_shost(cdev));
 559                 put_device(cdev);
 560         }
 561         return shost;
 562 }
 563 EXPORT_SYMBOL(scsi_host_lookup);
 564
 565 /**
 566  * scsi_host_get - inc a Scsi_Host ref count
 567  * @shost:      Pointer to Scsi_Host to inc.
 568  **/
 569 struct Scsi_Host *scsi_host_get(struct Scsi_Host *shost)
 570 {
 571         if ((shost->shost_state == SHOST_DEL) ||
 572                 !get_device(&shost->shost_gendev))
 573                 return NULL;
 574         return shost;
 575 }
 576 EXPORT_SYMBOL(scsi_host_get);
 577
 578 /**
 579  * scsi_host_busy - Return the host busy counter
 580  * @shost:      Pointer to Scsi_Host to inc.
 581  **/
 582 int scsi_host_busy(struct Scsi_Host *shost)
 583 {
 584         return atomic_read(&shost->host_busy);
 585 }
 586 EXPORT_SYMBOL(scsi_host_busy);
 587
 588 /**
 589  * scsi_host_put - dec a Scsi_Host ref count
 590  * @shost:      Pointer to Scsi_Host to dec.
 591  **/
 592 void scsi_host_put(struct Scsi_Host *shost)
 593 {
 594         put_device(&shost->shost_gendev);
 595 }
 596 EXPORT_SYMBOL(scsi_host_put);
 597
 598 int scsi_init_hosts(void)
 599 {
 600         return class_register(&shost_class);
 601 }
 602
 603 void scsi_exit_hosts(void)
 604 {
 605         class_unregister(&shost_class);
 606         ida_destroy(&host_index_ida);
 607 }
 608
 609 int scsi_is_host_device(const struct device *dev)
 610 {
 611         return dev->type == &scsi_host_type;
 612 }
 613 EXPORT_SYMBOL(scsi_is_host_device);
 614
 615 /**
 616  * scsi_queue_work - Queue work to the Scsi_Host workqueue.
 617  * @shost:      Pointer to Scsi_Host.
 618  * @work:       Work to queue for execution.
 619  *
 620  * Return value:
 621  *      1 - work queued for execution
 622  *      0 - work is already queued
 623  *      -EINVAL - work queue doesn't exist
 624  **/
 625 int scsi_queue_work(struct Scsi_Host *shost, struct work_struct *work)
 626 {
 627         if (unlikely(!shost->work_q)) {
 628                 shost_printk(KERN_ERR, shost,
 629                         "ERROR: Scsi host '%s' attempted to queue scsi-work, "
 630                         "when no workqueue created.\n", shost->hostt->name);
 631                 dump_stack();
 632
 633                 return -EINVAL;
 634         }
 635
 636         return queue_work(shost->work_q, work);
 637 }
 638 EXPORT_SYMBOL_GPL(scsi_queue_work);
 639
 640 /**
 641  * scsi_flush_work - Flush a Scsi_Host's workqueue.
 642  * @shost:      Pointer to Scsi_Host.
 643  **/
 644 void scsi_flush_work(struct Scsi_Host *shost)
 645 {
 646         if (!shost->work_q) {
 647                 shost_printk(KERN_ERR, shost,
 648                         "ERROR: Scsi host '%s' attempted to flush scsi-work, "
 649                         "when no workqueue created.\n", shost->hostt->name);
 650                 dump_stack();
 651                 return;
 652         }
 653
 654         flush_workqueue(shost->work_q);
 655 }
 656 EXPORT_SYMBOL_GPL(scsi_flush_work);