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         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         if (!dma_dev)
 222                 dma_dev = shost->shost_gendev.parent;
 223
 224         shost->dma_dev = dma_dev;
 225
 226         error = device_add(&shost->shost_gendev);
 227         if (error)
 228                 goto out;
 229
 230         pm_runtime_set_active(&shost->shost_gendev);
 231         pm_runtime_enable(&shost->shost_gendev);
 232         device_enable_async_suspend(&shost->shost_gendev);
 233
 234         scsi_host_set_state(shost, SHOST_RUNNING);
 235         get_device(shost->shost_gendev.parent);
 236
 237         device_enable_async_suspend(&shost->shost_dev);
 238
 239         error = device_add(&shost->shost_dev);
 240         if (error)
 241                 goto out_del_gendev;
 242
 243         get_device(&shost->shost_gendev);
 244
 245         if (shost->transportt->host_size) {
 246                 shost->shost_data = kzalloc(shost->transportt->host_size,
 247                                          GFP_KERNEL);
 248                 if (shost->shost_data == NULL) {
 249                         error = -ENOMEM;
 250                         goto out_del_dev;
 251                 }
 252         }
 253
 254         if (shost->transportt->create_work_queue) {
 255                 snprintf(shost->work_q_name, sizeof(shost->work_q_name),
 256                          "scsi_wq_%d", shost->host_no);
 257                 shost->work_q = create_singlethread_workqueue(
 258                                         shost->work_q_name);
 259                 if (!shost->work_q) {
 260                         error = -EINVAL;
 261                         goto out_free_shost_data;
 262                 }
 263         }
 264
 265         error = scsi_sysfs_add_host(shost);
 266         if (error)
 267                 goto out_destroy_host;
 268
 269         scsi_proc_host_add(shost);
 270         return error;
 271
 272  out_destroy_host:
 273         if (shost->work_q)
 274                 destroy_workqueue(shost->work_q);
 275  out_free_shost_data:
 276         kfree(shost->shost_data);
 277  out_del_dev:
 278         device_del(&shost->shost_dev);
 279  out_del_gendev:
 280         device_del(&shost->shost_gendev);
 281  out:
 282         scsi_destroy_command_freelist(shost);
 283  fail:
 284         return error;
 285 }
 286 EXPORT_SYMBOL(scsi_add_host_with_dma);
 287
 288 static void scsi_host_dev_release(struct device *dev)
 289 {
 290         struct Scsi_Host *shost = dev_to_shost(dev);
 291         struct device *parent = dev->parent;
 292         struct request_queue *q;
 293         void *queuedata;
 294
 295         scsi_proc_hostdir_rm(shost->hostt);
 296
 297         if (shost->ehandler)
 298                 kthread_stop(shost->ehandler);
 299         if (shost->work_q)
 300                 destroy_workqueue(shost->work_q);
 301         q = shost->uspace_req_q;
 302         if (q) {
 303                 queuedata = q->queuedata;
 304                 blk_cleanup_queue(q);
 305                 kfree(queuedata);
 306         }
 307
 308         scsi_destroy_command_freelist(shost);
 309         if (shost->bqt)
 310                 blk_free_tags(shost->bqt);
 311
 312         kfree(shost->shost_data);
 313
 314         if (parent)
 315                 put_device(parent);
 316         kfree(shost);
 317 }
 318
 319 static unsigned int shost_eh_deadline;
 320
 321 module_param_named(eh_deadline, shost_eh_deadline, uint, S_IRUGO|S_IWUSR);
 322 MODULE_PARM_DESC(eh_deadline,
 323                  "SCSI EH timeout in seconds (should be between 1 and 2^32-1)");
 324
 325 static struct device_type scsi_host_type = {
 326         .name =         "scsi_host",
 327         .release =      scsi_host_dev_release,
 328 };
 329
 330 /**
 331  * scsi_host_alloc - register a scsi host adapter instance.
 332  * @sht:        pointer to scsi host template
 333  * @privsize:   extra bytes to allocate for driver
 334  *
 335  * Note:
 336  *      Allocate a new Scsi_Host and perform basic initialization.
 337  *      The host is not published to the scsi midlayer until scsi_add_host
 338  *      is called.
 339  *
 340  * Return value:
 341  *      Pointer to a new Scsi_Host
 342  **/
 343 struct Scsi_Host *scsi_host_alloc(struct scsi_host_template *sht, int privsize)
 344 {
 345         struct Scsi_Host *shost;
 346         gfp_t gfp_mask = GFP_KERNEL;
 347
 348         if (sht->unchecked_isa_dma && privsize)
 349                 gfp_mask |= __GFP_DMA;
 350
 351         shost = kzalloc(sizeof(struct Scsi_Host) + privsize, gfp_mask);
 352         if (!shost)
 353                 return NULL;
 354
 355         shost->host_lock = &shost->default_lock;
 356         spin_lock_init(shost->host_lock);
 357         shost->shost_state = SHOST_CREATED;
 358         INIT_LIST_HEAD(&shost->__devices);
 359         INIT_LIST_HEAD(&shost->__targets);
 360         INIT_LIST_HEAD(&shost->eh_cmd_q);
 361         INIT_LIST_HEAD(&shost->starved_list);
 362         init_waitqueue_head(&shost->host_wait);
 363
 364         mutex_init(&shost->scan_mutex);
 365
 366         /*
 367          * subtract one because we increment first then return, but we need to
 368          * know what the next host number was before increment
 369          */
 370         shost->host_no = atomic_inc_return(&scsi_host_next_hn) - 1;
 371         shost->dma_channel = 0xff;
 372
 373         /* These three are default values which can be overridden */
 374         shost->max_channel = 0;
 375         shost->max_id = 8;
 376         shost->max_lun = 8;
 377
 378         /* Give each shost a default transportt */
 379         shost->transportt = &blank_transport_template;
 380
 381         /*
 382          * All drivers right now should be able to handle 12 byte
 383          * commands.  Every so often there are requests for 16 byte
 384          * commands, but individual low-level drivers need to certify that
 385          * they actually do something sensible with such commands.
 386          */
 387         shost->max_cmd_len = 12;
 388         shost->hostt = sht;
 389         shost->this_id = sht->this_id;
 390         shost->can_queue = sht->can_queue;
 391         shost->sg_tablesize = sht->sg_tablesize;
 392         shost->sg_prot_tablesize = sht->sg_prot_tablesize;
 393         shost->cmd_per_lun = sht->cmd_per_lun;
 394         shost->unchecked_isa_dma = sht->unchecked_isa_dma;
 395         shost->use_clustering = sht->use_clustering;
 396         shost->ordered_tag = sht->ordered_tag;
 397         shost->eh_deadline = shost_eh_deadline * HZ;
 398         shost->no_write_same = sht->no_write_same;
 399
 400         if (sht->supported_mode == MODE_UNKNOWN)
 401                 /* means we didn't set it ... default to INITIATOR */
 402                 shost->active_mode = MODE_INITIATOR;
 403         else
 404                 shost->active_mode = sht->supported_mode;
 405
 406         if (sht->max_host_blocked)
 407                 shost->max_host_blocked = sht->max_host_blocked;
 408         else
 409                 shost->max_host_blocked = SCSI_DEFAULT_HOST_BLOCKED;
 410
 411         /*
 412          * If the driver imposes no hard sector transfer limit, start at
 413          * machine infinity initially.
 414          */
 415         if (sht->max_sectors)
 416                 shost->max_sectors = sht->max_sectors;
 417         else
 418                 shost->max_sectors = SCSI_DEFAULT_MAX_SECTORS;
 419
 420         /*
 421          * assume a 4GB boundary, if not set
 422          */
 423         if (sht->dma_boundary)
 424                 shost->dma_boundary = sht->dma_boundary;
 425         else
 426                 shost->dma_boundary = 0xffffffff;
 427
 428         device_initialize(&shost->shost_gendev);
 429         dev_set_name(&shost->shost_gendev, "host%d", shost->host_no);
 430         shost->shost_gendev.bus = &scsi_bus_type;
 431         shost->shost_gendev.type = &scsi_host_type;
 432
 433         device_initialize(&shost->shost_dev);
 434         shost->shost_dev.parent = &shost->shost_gendev;
 435         shost->shost_dev.class = &shost_class;
 436         dev_set_name(&shost->shost_dev, "host%d", shost->host_no);
 437         shost->shost_dev.groups = scsi_sysfs_shost_attr_groups;
 438
 439         shost->ehandler = kthread_run(scsi_error_handler, shost,
 440                         "scsi_eh_%d", shost->host_no);
 441         if (IS_ERR(shost->ehandler)) {
 442                 printk(KERN_WARNING "scsi%d: error handler thread failed to spawn, error = %ld\n",
 443                         shost->host_no, PTR_ERR(shost->ehandler));
 444                 goto fail_kfree;
 445         }
 446
 447         scsi_proc_hostdir_add(shost->hostt);
 448         return shost;
 449
 450  fail_kfree:
 451         kfree(shost);
 452         return NULL;
 453 }
 454 EXPORT_SYMBOL(scsi_host_alloc);
 455
 456 struct Scsi_Host *scsi_register(struct scsi_host_template *sht, int privsize)
 457 {
 458         struct Scsi_Host *shost = scsi_host_alloc(sht, privsize);
 459
 460         if (!sht->detect) {
 461                 printk(KERN_WARNING "scsi_register() called on new-style "
 462                                     "template for driver %s\n", sht->name);
 463                 dump_stack();
 464         }
 465
 466         if (shost)
 467                 list_add_tail(&shost->sht_legacy_list, &sht->legacy_hosts);
 468         return shost;
 469 }
 470 EXPORT_SYMBOL(scsi_register);
 471
 472 void scsi_unregister(struct Scsi_Host *shost)
 473 {
 474         list_del(&shost->sht_legacy_list);
 475         scsi_host_put(shost);
 476 }
 477 EXPORT_SYMBOL(scsi_unregister);
 478
 479 static int __scsi_host_match(struct device *dev, const void *data)
 480 {
 481         struct Scsi_Host *p;
 482         const unsigned short *hostnum = data;
 483
 484         p = class_to_shost(dev);
 485         return p->host_no == *hostnum;
 486 }
 487
 488 /**
 489  * scsi_host_lookup - get a reference to a Scsi_Host by host no
 490  * @hostnum:    host number to locate
 491  *
 492  * Return value:
 493  *      A pointer to located Scsi_Host or NULL.
 494  *
 495  *      The caller must do a scsi_host_put() to drop the reference
 496  *      that scsi_host_get() took. The put_device() below dropped
 497  *      the reference from class_find_device().
 498  **/
 499 struct Scsi_Host *scsi_host_lookup(unsigned short hostnum)
 500 {
 501         struct device *cdev;
 502         struct Scsi_Host *shost = NULL;
 503
 504         cdev = class_find_device(&shost_class, NULL, &hostnum,
 505                                  __scsi_host_match);
 506         if (cdev) {
 507                 shost = scsi_host_get(class_to_shost(cdev));
 508                 put_device(cdev);
 509         }
 510         return shost;
 511 }
 512 EXPORT_SYMBOL(scsi_host_lookup);
 513
 514 /**
 515  * scsi_host_get - inc a Scsi_Host ref count
 516  * @shost:      Pointer to Scsi_Host to inc.
 517  **/
 518 struct Scsi_Host *scsi_host_get(struct Scsi_Host *shost)
 519 {
 520         if ((shost->shost_state == SHOST_DEL) ||
 521                 !get_device(&shost->shost_gendev))
 522                 return NULL;
 523         return shost;
 524 }
 525 EXPORT_SYMBOL(scsi_host_get);
 526
 527 /**
 528  * scsi_host_put - dec a Scsi_Host ref count
 529  * @shost:      Pointer to Scsi_Host to dec.
 530  **/
 531 void scsi_host_put(struct Scsi_Host *shost)
 532 {
 533         put_device(&shost->shost_gendev);
 534 }
 535 EXPORT_SYMBOL(scsi_host_put);
 536
 537 int scsi_init_hosts(void)
 538 {
 539         return class_register(&shost_class);
 540 }
 541
 542 void scsi_exit_hosts(void)
 543 {
 544         class_unregister(&shost_class);
 545 }
 546
 547 int scsi_is_host_device(const struct device *dev)
 548 {
 549         return dev->type == &scsi_host_type;
 550 }
 551 EXPORT_SYMBOL(scsi_is_host_device);
 552
 553 /**
 554  * scsi_queue_work - Queue work to the Scsi_Host workqueue.
 555  * @shost:      Pointer to Scsi_Host.
 556  * @work:       Work to queue for execution.
 557  *
 558  * Return value:
 559  *      1 - work queued for execution
 560  *      0 - work is already queued
 561  *      -EINVAL - work queue doesn't exist
 562  **/
 563 int scsi_queue_work(struct Scsi_Host *shost, struct work_struct *work)
 564 {
 565         if (unlikely(!shost->work_q)) {
 566                 printk(KERN_ERR
 567                         "ERROR: Scsi host '%s' attempted to queue scsi-work, "
 568                         "when no workqueue created.\n", shost->hostt->name);
 569                 dump_stack();
 570
 571                 return -EINVAL;
 572         }
 573
 574         return queue_work(shost->work_q, work);
 575 }
 576 EXPORT_SYMBOL_GPL(scsi_queue_work);
 577
 578 /**
 579  * scsi_flush_work - Flush a Scsi_Host's workqueue.
 580  * @shost:      Pointer to Scsi_Host.
 581  **/
 582 void scsi_flush_work(struct Scsi_Host *shost)
 583 {
 584         if (!shost->work_q) {
 585                 printk(KERN_ERR
 586                         "ERROR: Scsi host '%s' attempted to flush scsi-work, "
 587                         "when no workqueue created.\n", shost->hostt->name);
 588                 dump_stack();
 589                 return;
 590         }
 591
 592         flush_workqueue(shost->work_q);
 593 }
 594 EXPORT_SYMBOL_GPL(scsi_flush_work);