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
  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 atomic_t scsi_host_next_hn = ATOMIC_INIT(0);     /* host_no for next new host */
  46
  47
  48 static void scsi_host_cls_release(struct device *dev)
  49 {
  50         put_device(&class_to_shost(dev)->shost_gendev);
  51 }
  52
  53 static struct class shost_class = {
  54         .name           = "scsi_host",
  55         .dev_release    = scsi_host_cls_release,
  56 };
  57
  58 /**
  59  *      scsi_host_set_state - Take the given host through the host state model.
  60  *      @shost: scsi host to change the state of.
  61  *      @state: state to change to.
  62  *
  63  *      Returns zero if unsuccessful or an error if the requested
  64  *      transition is illegal.
  65  **/
  66 int scsi_host_set_state(struct Scsi_Host *shost, enum scsi_host_state state)
  67 {
  68         enum scsi_host_state oldstate = shost->shost_state;
  69
  70         if (state == oldstate)
  71                 return 0;
  72
  73         switch (state) {
  74         case SHOST_CREATED:
  75                 /* There are no legal states that come back to
  76                  * created.  This is the manually initialised start
  77                  * state */
  78                 goto illegal;
  79
  80         case SHOST_RUNNING:
  81                 switch (oldstate) {
  82                 case SHOST_CREATED:
  83                 case SHOST_RECOVERY:
  84                         break;
  85                 default:
  86                         goto illegal;
  87                 }
  88                 break;
  89
  90         case SHOST_RECOVERY:
  91                 switch (oldstate) {
  92                 case SHOST_RUNNING:
  93                         break;
  94                 default:
  95                         goto illegal;
  96                 }
  97                 break;
  98
  99         case SHOST_CANCEL:
 100                 switch (oldstate) {
 101                 case SHOST_CREATED:
 102                 case SHOST_RUNNING:
 103                 case SHOST_CANCEL_RECOVERY:
 104                         break;
 105                 default:
 106                         goto illegal;
 107                 }
 108                 break;
 109
 110         case SHOST_DEL:
 111                 switch (oldstate) {
 112                 case SHOST_CANCEL:
 113                 case SHOST_DEL_RECOVERY:
 114                         break;
 115                 default:
 116                         goto illegal;
 117                 }
 118                 break;
 119
 120         case SHOST_CANCEL_RECOVERY:
 121                 switch (oldstate) {
 122                 case SHOST_CANCEL:
 123                 case SHOST_RECOVERY:
 124                         break;
 125                 default:
 126                         goto illegal;
 127                 }
 128                 break;
 129
 130         case SHOST_DEL_RECOVERY:
 131                 switch (oldstate) {
 132                 case SHOST_CANCEL_RECOVERY:
 133                         break;
 134                 default:
 135                         goto illegal;
 136                 }
 137                 break;
 138         }
 139         shost->shost_state = state;
 140         return 0;
 141
 142  illegal:
 143         SCSI_LOG_ERROR_RECOVERY(1,
 144                                 shost_printk(KERN_ERR, shost,
 145                                              "Illegal host state transition"
 146                                              "%s->%s\n",
 147                                              scsi_host_state_name(oldstate),
 148                                              scsi_host_state_name(state)));
 149         return -EINVAL;
 150 }
 151 EXPORT_SYMBOL(scsi_host_set_state);
 152
 153 /**
 154  * scsi_remove_host - remove a scsi host
 155  * @shost:      a pointer to a scsi host to remove
 156  **/
 157 void scsi_remove_host(struct Scsi_Host *shost)
 158 {
 159         unsigned long flags;
 160
 161         mutex_lock(&shost->scan_mutex);
 162         spin_lock_irqsave(shost->host_lock, flags);
 163         if (scsi_host_set_state(shost, SHOST_CANCEL))
 164                 if (scsi_host_set_state(shost, SHOST_CANCEL_RECOVERY)) {
 165                         spin_unlock_irqrestore(shost->host_lock, flags);
 166                         mutex_unlock(&shost->scan_mutex);
 167                         return;
 168                 }
 169         spin_unlock_irqrestore(shost->host_lock, flags);
 170
 171         scsi_autopm_get_host(shost);
 172         flush_workqueue(shost->tmf_work_q);
 173         scsi_forget_host(shost);
 174         mutex_unlock(&shost->scan_mutex);
 175         scsi_proc_host_rm(shost);
 176
 177         spin_lock_irqsave(shost->host_lock, flags);
 178         if (scsi_host_set_state(shost, SHOST_DEL))
 179                 BUG_ON(scsi_host_set_state(shost, SHOST_DEL_RECOVERY));
 180         spin_unlock_irqrestore(shost->host_lock, flags);
 181
 182         transport_unregister_device(&shost->shost_gendev);
 183         device_unregister(&shost->shost_dev);
 184         device_del(&shost->shost_gendev);
 185 }
 186 EXPORT_SYMBOL(scsi_remove_host);
 187
 188 /**
 189  * scsi_add_host_with_dma - add a scsi host with dma device
 190  * @shost:      scsi host pointer to add
 191  * @dev:        a struct device of type scsi class
 192  * @dma_dev:    dma device for the host
 193  *
 194  * Note: You rarely need to worry about this unless you're in a
 195  * virtualised host environments, so use the simpler scsi_add_host()
 196  * function instead.
 197  *
 198  * Return value:
 199  *      0 on success / != 0 for error
 200  **/
 201 int scsi_add_host_with_dma(struct Scsi_Host *shost, struct device *dev,
 202                            struct device *dma_dev)
 203 {
 204         struct scsi_host_template *sht = shost->hostt;
 205         int error = -EINVAL;
 206
 207         printk(KERN_INFO "scsi%d : %s\n", shost->host_no,
 208                         sht->info ? sht->info(shost) : sht->name);
 209
 210         if (!shost->can_queue) {
 211                 printk(KERN_ERR "%s: can_queue = 0 no longer supported\n",
 212                                 sht->name);
 213                 goto fail;
 214         }
 215
 216         error = scsi_setup_command_freelist(shost);
 217         if (error)
 218                 goto fail;
 219
 220         if (!shost->shost_gendev.parent)
 221                 shost->shost_gendev.parent = dev ? dev : &platform_bus;
 222         if (!dma_dev)
 223                 dma_dev = shost->shost_gendev.parent;
 224
 225         shost->dma_dev = dma_dev;
 226
 227         error = device_add(&shost->shost_gendev);
 228         if (error)
 229                 goto out;
 230
 231         pm_runtime_set_active(&shost->shost_gendev);
 232         pm_runtime_enable(&shost->shost_gendev);
 233         device_enable_async_suspend(&shost->shost_gendev);
 234
 235         scsi_host_set_state(shost, SHOST_RUNNING);
 236         get_device(shost->shost_gendev.parent);
 237
 238         device_enable_async_suspend(&shost->shost_dev);
 239
 240         error = device_add(&shost->shost_dev);
 241         if (error)
 242                 goto out_del_gendev;
 243
 244         get_device(&shost->shost_gendev);
 245
 246         if (shost->transportt->host_size) {
 247                 shost->shost_data = kzalloc(shost->transportt->host_size,
 248                                          GFP_KERNEL);
 249                 if (shost->shost_data == NULL) {
 250                         error = -ENOMEM;
 251                         goto out_del_dev;
 252                 }
 253         }
 254
 255         if (shost->transportt->create_work_queue) {
 256                 snprintf(shost->work_q_name, sizeof(shost->work_q_name),
 257                          "scsi_wq_%d", shost->host_no);
 258                 shost->work_q = create_singlethread_workqueue(
 259                                         shost->work_q_name);
 260                 if (!shost->work_q) {
 261                         error = -EINVAL;
 262                         goto out_free_shost_data;
 263                 }
 264         }
 265
 266         error = scsi_sysfs_add_host(shost);
 267         if (error)
 268                 goto out_destroy_host;
 269
 270         scsi_proc_host_add(shost);
 271         return error;
 272
 273  out_destroy_host:
 274         if (shost->work_q)
 275                 destroy_workqueue(shost->work_q);
 276  out_free_shost_data:
 277         kfree(shost->shost_data);
 278  out_del_dev:
 279         device_del(&shost->shost_dev);
 280  out_del_gendev:
 281         device_del(&shost->shost_gendev);
 282  out:
 283         scsi_destroy_command_freelist(shost);
 284  fail:
 285         return error;
 286 }
 287 EXPORT_SYMBOL(scsi_add_host_with_dma);
 288
 289 static void scsi_host_dev_release(struct device *dev)
 290 {
 291         struct Scsi_Host *shost = dev_to_shost(dev);
 292         struct device *parent = dev->parent;
 293         struct request_queue *q;
 294         void *queuedata;
 295
 296         scsi_proc_hostdir_rm(shost->hostt);
 297
 298         if (shost->tmf_work_q)
 299                 destroy_workqueue(shost->tmf_work_q);
 300         if (shost->ehandler)
 301                 kthread_stop(shost->ehandler);
 302         if (shost->work_q)
 303                 destroy_workqueue(shost->work_q);
 304         q = shost->uspace_req_q;
 305         if (q) {
 306                 queuedata = q->queuedata;
 307                 blk_cleanup_queue(q);
 308                 kfree(queuedata);
 309         }
 310
 311         scsi_destroy_command_freelist(shost);
 312         if (shost->bqt)
 313                 blk_free_tags(shost->bqt);
 314
 315         kfree(shost->shost_data);
 316
 317         if (parent)
 318                 put_device(parent);
 319         kfree(shost);
 320 }
 321
 322 static unsigned int shost_eh_deadline;
 323
 324 module_param_named(eh_deadline, shost_eh_deadline, uint, S_IRUGO|S_IWUSR);
 325 MODULE_PARM_DESC(eh_deadline,
 326                  "SCSI EH timeout in seconds (should be between 1 and 2^32-1)");
 327
 328 static struct device_type scsi_host_type = {
 329         .name =         "scsi_host",
 330         .release =      scsi_host_dev_release,
 331 };
 332
 333 /**
 334  * scsi_host_alloc - register a scsi host adapter instance.
 335  * @sht:        pointer to scsi host template
 336  * @privsize:   extra bytes to allocate for driver
 337  *
 338  * Note:
 339  *      Allocate a new Scsi_Host and perform basic initialization.
 340  *      The host is not published to the scsi midlayer until scsi_add_host
 341  *      is called.
 342  *
 343  * Return value:
 344  *      Pointer to a new Scsi_Host
 345  **/
 346 struct Scsi_Host *scsi_host_alloc(struct scsi_host_template *sht, int privsize)
 347 {
 348         struct Scsi_Host *shost;
 349         gfp_t gfp_mask = GFP_KERNEL;
 350
 351         if (sht->unchecked_isa_dma && privsize)
 352                 gfp_mask |= __GFP_DMA;
 353
 354         shost = kzalloc(sizeof(struct Scsi_Host) + privsize, gfp_mask);
 355         if (!shost)
 356                 return NULL;
 357
 358         shost->host_lock = &shost->default_lock;
 359         spin_lock_init(shost->host_lock);
 360         shost->shost_state = SHOST_CREATED;
 361         INIT_LIST_HEAD(&shost->__devices);
 362         INIT_LIST_HEAD(&shost->__targets);
 363         INIT_LIST_HEAD(&shost->eh_cmd_q);
 364         INIT_LIST_HEAD(&shost->starved_list);
 365         init_waitqueue_head(&shost->host_wait);
 366         mutex_init(&shost->scan_mutex);
 367
 368         /*
 369          * subtract one because we increment first then return, but we need to
 370          * know what the next host number was before increment
 371          */
 372         shost->host_no = atomic_inc_return(&scsi_host_next_hn) - 1;
 373         shost->dma_channel = 0xff;
 374
 375         /* These three are default values which can be overridden */
 376         shost->max_channel = 0;
 377         shost->max_id = 8;
 378         shost->max_lun = 8;
 379
 380         /* Give each shost a default transportt */
 381         shost->transportt = &blank_transport_template;
 382
 383         /*
 384          * All drivers right now should be able to handle 12 byte
 385          * commands.  Every so often there are requests for 16 byte
 386          * commands, but individual low-level drivers need to certify that
 387          * they actually do something sensible with such commands.
 388          */
 389         shost->max_cmd_len = 12;
 390         shost->hostt = sht;
 391         shost->this_id = sht->this_id;
 392         shost->can_queue = sht->can_queue;
 393         shost->sg_tablesize = sht->sg_tablesize;
 394         shost->sg_prot_tablesize = sht->sg_prot_tablesize;
 395         shost->cmd_per_lun = sht->cmd_per_lun;
 396         shost->unchecked_isa_dma = sht->unchecked_isa_dma;
 397         shost->use_clustering = sht->use_clustering;
 398         shost->ordered_tag = sht->ordered_tag;
 399         shost->eh_deadline = shost_eh_deadline * HZ;
 400         shost->no_write_same = sht->no_write_same;
 401
 402         if (sht->supported_mode == MODE_UNKNOWN)
 403                 /* means we didn't set it ... default to INITIATOR */
 404                 shost->active_mode = MODE_INITIATOR;
 405         else
 406                 shost->active_mode = sht->supported_mode;
 407
 408         if (sht->max_host_blocked)
 409                 shost->max_host_blocked = sht->max_host_blocked;
 410         else
 411                 shost->max_host_blocked = SCSI_DEFAULT_HOST_BLOCKED;
 412
 413         /*
 414          * If the driver imposes no hard sector transfer limit, start at
 415          * machine infinity initially.
 416          */
 417         if (sht->max_sectors)
 418                 shost->max_sectors = sht->max_sectors;
 419         else
 420                 shost->max_sectors = SCSI_DEFAULT_MAX_SECTORS;
 421
 422         /*
 423          * assume a 4GB boundary, if not set
 424          */
 425         if (sht->dma_boundary)
 426                 shost->dma_boundary = sht->dma_boundary;
 427         else
 428                 shost->dma_boundary = 0xffffffff;
 429
 430         device_initialize(&shost->shost_gendev);
 431         dev_set_name(&shost->shost_gendev, "host%d", shost->host_no);
 432         shost->shost_gendev.bus = &scsi_bus_type;
 433         shost->shost_gendev.type = &scsi_host_type;
 434
 435         device_initialize(&shost->shost_dev);
 436         shost->shost_dev.parent = &shost->shost_gendev;
 437         shost->shost_dev.class = &shost_class;
 438         dev_set_name(&shost->shost_dev, "host%d", shost->host_no);
 439         shost->shost_dev.groups = scsi_sysfs_shost_attr_groups;
 440
 441         shost->ehandler = kthread_run(scsi_error_handler, shost,
 442                         "scsi_eh_%d", shost->host_no);
 443         if (IS_ERR(shost->ehandler)) {
 444                 printk(KERN_WARNING "scsi%d: error handler thread failed to spawn, error = %ld\n",
 445                         shost->host_no, PTR_ERR(shost->ehandler));
 446                 goto fail_kfree;
 447         }
 448
 449         shost->tmf_work_q = alloc_workqueue("scsi_tmf_%d",
 450                                             WQ_UNBOUND | WQ_MEM_RECLAIM,
 451                                            1, shost->host_no);
 452         if (!shost->tmf_work_q) {
 453                 printk(KERN_WARNING "scsi%d: failed to create tmf workq\n",
 454                        shost->host_no);
 455                 goto fail_kthread;
 456         }
 457         scsi_proc_hostdir_add(shost->hostt);
 458         return shost;
 459
 460  fail_kthread:
 461         kthread_stop(shost->ehandler);
 462  fail_kfree:
 463         kfree(shost);
 464         return NULL;
 465 }
 466 EXPORT_SYMBOL(scsi_host_alloc);
 467
 468 struct Scsi_Host *scsi_register(struct scsi_host_template *sht, int privsize)
 469 {
 470         struct Scsi_Host *shost = scsi_host_alloc(sht, privsize);
 471
 472         if (!sht->detect) {
 473                 printk(KERN_WARNING "scsi_register() called on new-style "
 474                                     "template for driver %s\n", sht->name);
 475                 dump_stack();
 476         }
 477
 478         if (shost)
 479                 list_add_tail(&shost->sht_legacy_list, &sht->legacy_hosts);
 480         return shost;
 481 }
 482 EXPORT_SYMBOL(scsi_register);
 483
 484 void scsi_unregister(struct Scsi_Host *shost)
 485 {
 486         list_del(&shost->sht_legacy_list);
 487         scsi_host_put(shost);
 488 }
 489 EXPORT_SYMBOL(scsi_unregister);
 490
 491 static int __scsi_host_match(struct device *dev, const void *data)
 492 {
 493         struct Scsi_Host *p;
 494         const unsigned short *hostnum = data;
 495
 496         p = class_to_shost(dev);
 497         return p->host_no == *hostnum;
 498 }
 499
 500 /**
 501  * scsi_host_lookup - get a reference to a Scsi_Host by host no
 502  * @hostnum:    host number to locate
 503  *
 504  * Return value:
 505  *      A pointer to located Scsi_Host or NULL.
 506  *
 507  *      The caller must do a scsi_host_put() to drop the reference
 508  *      that scsi_host_get() took. The put_device() below dropped
 509  *      the reference from class_find_device().
 510  **/
 511 struct Scsi_Host *scsi_host_lookup(unsigned short hostnum)
 512 {
 513         struct device *cdev;
 514         struct Scsi_Host *shost = NULL;
 515
 516         cdev = class_find_device(&shost_class, NULL, &hostnum,
 517                                  __scsi_host_match);
 518         if (cdev) {
 519                 shost = scsi_host_get(class_to_shost(cdev));
 520                 put_device(cdev);
 521         }
 522         return shost;
 523 }
 524 EXPORT_SYMBOL(scsi_host_lookup);
 525
 526 /**
 527  * scsi_host_get - inc a Scsi_Host ref count
 528  * @shost:      Pointer to Scsi_Host to inc.
 529  **/
 530 struct Scsi_Host *scsi_host_get(struct Scsi_Host *shost)
 531 {
 532         if ((shost->shost_state == SHOST_DEL) ||
 533                 !get_device(&shost->shost_gendev))
 534                 return NULL;
 535         return shost;
 536 }
 537 EXPORT_SYMBOL(scsi_host_get);
 538
 539 /**
 540  * scsi_host_put - dec a Scsi_Host ref count
 541  * @shost:      Pointer to Scsi_Host to dec.
 542  **/
 543 void scsi_host_put(struct Scsi_Host *shost)
 544 {
 545         put_device(&shost->shost_gendev);
 546 }
 547 EXPORT_SYMBOL(scsi_host_put);
 548
 549 int scsi_init_hosts(void)
 550 {
 551         return class_register(&shost_class);
 552 }
 553
 554 void scsi_exit_hosts(void)
 555 {
 556         class_unregister(&shost_class);
 557 }
 558
 559 int scsi_is_host_device(const struct device *dev)
 560 {
 561         return dev->type == &scsi_host_type;
 562 }
 563 EXPORT_SYMBOL(scsi_is_host_device);
 564
 565 /**
 566  * scsi_queue_work - Queue work to the Scsi_Host workqueue.
 567  * @shost:      Pointer to Scsi_Host.
 568  * @work:       Work to queue for execution.
 569  *
 570  * Return value:
 571  *      1 - work queued for execution
 572  *      0 - work is already queued
 573  *      -EINVAL - work queue doesn't exist
 574  **/
 575 int scsi_queue_work(struct Scsi_Host *shost, struct work_struct *work)
 576 {
 577         if (unlikely(!shost->work_q)) {
 578                 printk(KERN_ERR
 579                         "ERROR: Scsi host '%s' attempted to queue scsi-work, "
 580                         "when no workqueue created.\n", shost->hostt->name);
 581                 dump_stack();
 582
 583                 return -EINVAL;
 584         }
 585
 586         return queue_work(shost->work_q, work);
 587 }
 588 EXPORT_SYMBOL_GPL(scsi_queue_work);
 589
 590 /**
 591  * scsi_flush_work - Flush a Scsi_Host's workqueue.
 592  * @shost:      Pointer to Scsi_Host.
 593  **/
 594 void scsi_flush_work(struct Scsi_Host *shost)
 595 {
 596         if (!shost->work_q) {
 597                 printk(KERN_ERR
 598                         "ERROR: Scsi host '%s' attempted to flush scsi-work, "
 599                         "when no workqueue created.\n", shost->hostt->name);
 600                 dump_stack();
 601                 return;
 602         }
 603
 604         flush_workqueue(shost->work_q);
 605 }
 606 EXPORT_SYMBOL_GPL(scsi_flush_work);