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;      /* 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         scsi_forget_host(shost);
 173         mutex_unlock(&shost->scan_mutex);
 174         scsi_proc_host_rm(shost);
 175
 176         spin_lock_irqsave(shost->host_lock, flags);
 177         if (scsi_host_set_state(shost, SHOST_DEL))
 178                 BUG_ON(scsi_host_set_state(shost, SHOST_DEL_RECOVERY));
 179         spin_unlock_irqrestore(shost->host_lock, flags);
 180
 181         transport_unregister_device(&shost->shost_gendev);
 182         device_unregister(&shost->shost_dev);
 183         device_del(&shost->shost_gendev);
 184 }
 185 EXPORT_SYMBOL(scsi_remove_host);
 186
 187 /**
 188  * scsi_add_host_with_dma - add a scsi host with dma device
 189  * @shost:      scsi host pointer to add
 190  * @dev:        a struct device of type scsi class
 191  * @dma_dev:    dma device for the host
 192  *
 193  * Note: You rarely need to worry about this unless you're in a
 194  * virtualised host environments, so use the simpler scsi_add_host()
 195  * function instead.
 196  *
 197  * Return value:
 198  *      0 on success / != 0 for error
 199  **/
 200 int scsi_add_host_with_dma(struct Scsi_Host *shost, struct device *dev,
 201                            struct device *dma_dev)
 202 {
 203         struct scsi_host_template *sht = shost->hostt;
 204         int error = -EINVAL;
 205
 206         printk(KERN_INFO "scsi%d : %s\n", shost->host_no,
 207                         sht->info ? sht->info(shost) : sht->name);
 208
 209         if (!shost->can_queue) {
 210                 printk(KERN_ERR "%s: can_queue = 0 no longer supported\n",
 211                                 sht->name);
 212                 goto fail;
 213         }
 214
 215         error = scsi_setup_command_freelist(shost);
 216         if (error)
 217                 goto fail;
 218
 219         if (!shost->shost_gendev.parent)
 220                 shost->shost_gendev.parent = dev ? dev : &platform_bus;
 221         shost->dma_dev = dma_dev;
 222
 223         error = device_add(&shost->shost_gendev);
 224         if (error)
 225                 goto out;
 226
 227         pm_runtime_set_active(&shost->shost_gendev);
 228         pm_runtime_enable(&shost->shost_gendev);
 229         device_enable_async_suspend(&shost->shost_gendev);
 230
 231         scsi_host_set_state(shost, SHOST_RUNNING);
 232         get_device(shost->shost_gendev.parent);
 233
 234         device_enable_async_suspend(&shost->shost_dev);
 235
 236         error = device_add(&shost->shost_dev);
 237         if (error)
 238                 goto out_del_gendev;
 239
 240         get_device(&shost->shost_gendev);
 241
 242         if (shost->transportt->host_size) {
 243                 shost->shost_data = kzalloc(shost->transportt->host_size,
 244                                          GFP_KERNEL);
 245                 if (shost->shost_data == NULL) {
 246                         error = -ENOMEM;
 247                         goto out_del_dev;
 248                 }
 249         }
 250
 251         if (shost->transportt->create_work_queue) {
 252                 snprintf(shost->work_q_name, sizeof(shost->work_q_name),
 253                          "scsi_wq_%d", shost->host_no);
 254                 shost->work_q = create_singlethread_workqueue(
 255                                         shost->work_q_name);
 256                 if (!shost->work_q) {
 257                         error = -EINVAL;
 258                         goto out_free_shost_data;
 259                 }
 260         }
 261
 262         error = scsi_sysfs_add_host(shost);
 263         if (error)
 264                 goto out_destroy_host;
 265
 266         scsi_proc_host_add(shost);
 267         return error;
 268
 269  out_destroy_host:
 270         if (shost->work_q)
 271                 destroy_workqueue(shost->work_q);
 272  out_free_shost_data:
 273         kfree(shost->shost_data);
 274  out_del_dev:
 275         device_del(&shost->shost_dev);
 276  out_del_gendev:
 277         device_del(&shost->shost_gendev);
 278  out:
 279         scsi_destroy_command_freelist(shost);
 280  fail:
 281         return error;
 282 }
 283 EXPORT_SYMBOL(scsi_add_host_with_dma);
 284
 285 static void scsi_host_dev_release(struct device *dev)
 286 {
 287         struct Scsi_Host *shost = dev_to_shost(dev);
 288         struct device *parent = dev->parent;
 289         struct request_queue *q;
 290
 291         scsi_proc_hostdir_rm(shost->hostt);
 292
 293         if (shost->ehandler)
 294                 kthread_stop(shost->ehandler);
 295         if (shost->work_q)
 296                 destroy_workqueue(shost->work_q);
 297         q = shost->uspace_req_q;
 298         if (q) {
 299                 kfree(q->queuedata);
 300                 q->queuedata = NULL;
 301                 scsi_free_queue(q);
 302         }
 303
 304         scsi_destroy_command_freelist(shost);
 305         if (shost->bqt)
 306                 blk_free_tags(shost->bqt);
 307
 308         kfree(shost->shost_data);
 309
 310         if (parent)
 311                 put_device(parent);
 312         kfree(shost);
 313 }
 314
 315 static struct device_type scsi_host_type = {
 316         .name =         "scsi_host",
 317         .release =      scsi_host_dev_release,
 318 };
 319
 320 /**
 321  * scsi_host_alloc - register a scsi host adapter instance.
 322  * @sht:        pointer to scsi host template
 323  * @privsize:   extra bytes to allocate for driver
 324  *
 325  * Note:
 326  *      Allocate a new Scsi_Host and perform basic initialization.
 327  *      The host is not published to the scsi midlayer until scsi_add_host
 328  *      is called.
 329  *
 330  * Return value:
 331  *      Pointer to a new Scsi_Host
 332  **/
 333 struct Scsi_Host *scsi_host_alloc(struct scsi_host_template *sht, int privsize)
 334 {
 335         struct Scsi_Host *shost;
 336         gfp_t gfp_mask = GFP_KERNEL;
 337
 338         if (sht->unchecked_isa_dma && privsize)
 339                 gfp_mask |= __GFP_DMA;
 340
 341         shost = kzalloc(sizeof(struct Scsi_Host) + privsize, gfp_mask);
 342         if (!shost)
 343                 return NULL;
 344
 345         shost->host_lock = &shost->default_lock;
 346         spin_lock_init(shost->host_lock);
 347         shost->shost_state = SHOST_CREATED;
 348         INIT_LIST_HEAD(&shost->__devices);
 349         INIT_LIST_HEAD(&shost->__targets);
 350         INIT_LIST_HEAD(&shost->eh_cmd_q);
 351         INIT_LIST_HEAD(&shost->starved_list);
 352         init_waitqueue_head(&shost->host_wait);
 353
 354         mutex_init(&shost->scan_mutex);
 355
 356         /*
 357          * subtract one because we increment first then return, but we need to
 358          * know what the next host number was before increment
 359          */
 360         shost->host_no = atomic_inc_return(&scsi_host_next_hn) - 1;
 361         shost->dma_channel = 0xff;
 362
 363         /* These three are default values which can be overridden */
 364         shost->max_channel = 0;
 365         shost->max_id = 8;
 366         shost->max_lun = 8;
 367
 368         /* Give each shost a default transportt */
 369         shost->transportt = &blank_transport_template;
 370
 371         /*
 372          * All drivers right now should be able to handle 12 byte
 373          * commands.  Every so often there are requests for 16 byte
 374          * commands, but individual low-level drivers need to certify that
 375          * they actually do something sensible with such commands.
 376          */
 377         shost->max_cmd_len = 12;
 378         shost->hostt = sht;
 379         shost->this_id = sht->this_id;
 380         shost->can_queue = sht->can_queue;
 381         shost->sg_tablesize = sht->sg_tablesize;
 382         shost->sg_prot_tablesize = sht->sg_prot_tablesize;
 383         shost->cmd_per_lun = sht->cmd_per_lun;
 384         shost->unchecked_isa_dma = sht->unchecked_isa_dma;
 385         shost->use_clustering = sht->use_clustering;
 386         shost->ordered_tag = sht->ordered_tag;
 387
 388         if (sht->supported_mode == MODE_UNKNOWN)
 389                 /* means we didn't set it ... default to INITIATOR */
 390                 shost->active_mode = MODE_INITIATOR;
 391         else
 392                 shost->active_mode = sht->supported_mode;
 393
 394         if (sht->max_host_blocked)
 395                 shost->max_host_blocked = sht->max_host_blocked;
 396         else
 397                 shost->max_host_blocked = SCSI_DEFAULT_HOST_BLOCKED;
 398
 399         /*
 400          * If the driver imposes no hard sector transfer limit, start at
 401          * machine infinity initially.
 402          */
 403         if (sht->max_sectors)
 404                 shost->max_sectors = sht->max_sectors;
 405         else
 406                 shost->max_sectors = SCSI_DEFAULT_MAX_SECTORS;
 407
 408         /*
 409          * assume a 4GB boundary, if not set
 410          */
 411         if (sht->dma_boundary)
 412                 shost->dma_boundary = sht->dma_boundary;
 413         else
 414                 shost->dma_boundary = 0xffffffff;
 415
 416         device_initialize(&shost->shost_gendev);
 417         dev_set_name(&shost->shost_gendev, "host%d", shost->host_no);
 418         shost->shost_gendev.bus = &scsi_bus_type;
 419         shost->shost_gendev.type = &scsi_host_type;
 420
 421         device_initialize(&shost->shost_dev);
 422         shost->shost_dev.parent = &shost->shost_gendev;
 423         shost->shost_dev.class = &shost_class;
 424         dev_set_name(&shost->shost_dev, "host%d", shost->host_no);
 425         shost->shost_dev.groups = scsi_sysfs_shost_attr_groups;
 426
 427         shost->ehandler = kthread_run(scsi_error_handler, shost,
 428                         "scsi_eh_%d", shost->host_no);
 429         if (IS_ERR(shost->ehandler)) {
 430                 printk(KERN_WARNING "scsi%d: error handler thread failed to spawn, error = %ld\n",
 431                         shost->host_no, PTR_ERR(shost->ehandler));
 432                 goto fail_kfree;
 433         }
 434
 435         scsi_proc_hostdir_add(shost->hostt);
 436         return shost;
 437
 438  fail_kfree:
 439         kfree(shost);
 440         return NULL;
 441 }
 442 EXPORT_SYMBOL(scsi_host_alloc);
 443
 444 struct Scsi_Host *scsi_register(struct scsi_host_template *sht, int privsize)
 445 {
 446         struct Scsi_Host *shost = scsi_host_alloc(sht, privsize);
 447
 448         if (!sht->detect) {
 449                 printk(KERN_WARNING "scsi_register() called on new-style "
 450                                     "template for driver %s\n", sht->name);
 451                 dump_stack();
 452         }
 453
 454         if (shost)
 455                 list_add_tail(&shost->sht_legacy_list, &sht->legacy_hosts);
 456         return shost;
 457 }
 458 EXPORT_SYMBOL(scsi_register);
 459
 460 void scsi_unregister(struct Scsi_Host *shost)
 461 {
 462         list_del(&shost->sht_legacy_list);
 463         scsi_host_put(shost);
 464 }
 465 EXPORT_SYMBOL(scsi_unregister);
 466
 467 static int __scsi_host_match(struct device *dev, void *data)
 468 {
 469         struct Scsi_Host *p;
 470         unsigned short *hostnum = (unsigned short *)data;
 471
 472         p = class_to_shost(dev);
 473         return p->host_no == *hostnum;
 474 }
 475
 476 /**
 477  * scsi_host_lookup - get a reference to a Scsi_Host by host no
 478  * @hostnum:    host number to locate
 479  *
 480  * Return value:
 481  *      A pointer to located Scsi_Host or NULL.
 482  *
 483  *      The caller must do a scsi_host_put() to drop the reference
 484  *      that scsi_host_get() took. The put_device() below dropped
 485  *      the reference from class_find_device().
 486  **/
 487 struct Scsi_Host *scsi_host_lookup(unsigned short hostnum)
 488 {
 489         struct device *cdev;
 490         struct Scsi_Host *shost = NULL;
 491
 492         cdev = class_find_device(&shost_class, NULL, &hostnum,
 493                                  __scsi_host_match);
 494         if (cdev) {
 495                 shost = scsi_host_get(class_to_shost(cdev));
 496                 put_device(cdev);
 497         }
 498         return shost;
 499 }
 500 EXPORT_SYMBOL(scsi_host_lookup);
 501
 502 /**
 503  * scsi_host_get - inc a Scsi_Host ref count
 504  * @shost:      Pointer to Scsi_Host to inc.
 505  **/
 506 struct Scsi_Host *scsi_host_get(struct Scsi_Host *shost)
 507 {
 508         if ((shost->shost_state == SHOST_DEL) ||
 509                 !get_device(&shost->shost_gendev))
 510                 return NULL;
 511         return shost;
 512 }
 513 EXPORT_SYMBOL(scsi_host_get);
 514
 515 /**
 516  * scsi_host_put - dec a Scsi_Host ref count
 517  * @shost:      Pointer to Scsi_Host to dec.
 518  **/
 519 void scsi_host_put(struct Scsi_Host *shost)
 520 {
 521         put_device(&shost->shost_gendev);
 522 }
 523 EXPORT_SYMBOL(scsi_host_put);
 524
 525 int scsi_init_hosts(void)
 526 {
 527         return class_register(&shost_class);
 528 }
 529
 530 void scsi_exit_hosts(void)
 531 {
 532         class_unregister(&shost_class);
 533 }
 534
 535 int scsi_is_host_device(const struct device *dev)
 536 {
 537         return dev->type == &scsi_host_type;
 538 }
 539 EXPORT_SYMBOL(scsi_is_host_device);
 540
 541 /**
 542  * scsi_queue_work - Queue work to the Scsi_Host workqueue.
 543  * @shost:      Pointer to Scsi_Host.
 544  * @work:       Work to queue for execution.
 545  *
 546  * Return value:
 547  *      1 - work queued for execution
 548  *      0 - work is already queued
 549  *      -EINVAL - work queue doesn't exist
 550  **/
 551 int scsi_queue_work(struct Scsi_Host *shost, struct work_struct *work)
 552 {
 553         if (unlikely(!shost->work_q)) {
 554                 printk(KERN_ERR
 555                         "ERROR: Scsi host '%s' attempted to queue scsi-work, "
 556                         "when no workqueue created.\n", shost->hostt->name);
 557                 dump_stack();
 558
 559                 return -EINVAL;
 560         }
 561
 562         return queue_work(shost->work_q, work);
 563 }
 564 EXPORT_SYMBOL_GPL(scsi_queue_work);
 565
 566 /**
 567  * scsi_flush_work - Flush a Scsi_Host's workqueue.
 568  * @shost:      Pointer to Scsi_Host.
 569  **/
 570 void scsi_flush_work(struct Scsi_Host *shost)
 571 {
 572         if (!shost->work_q) {
 573                 printk(KERN_ERR
 574                         "ERROR: Scsi host '%s' attempted to flush scsi-work, "
 575                         "when no workqueue created.\n", shost->hostt->name);
 576                 dump_stack();
 577                 return;
 578         }
 579
 580         flush_workqueue(shost->work_q);
 581 }
 582 EXPORT_SYMBOL_GPL(scsi_flush_work);