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   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/kthread.h>
  28 #include <linux/string.h>
  29 #include <linux/mm.h>
  30 #include <linux/init.h>
  31 #include <linux/completion.h>
  32 #include <linux/transport_class.h>
  33
  34 #include <scsi/scsi_device.h>
  35 #include <scsi/scsi_host.h>
  36 #include <scsi/scsi_transport.h>
  37
  38 #include "scsi_priv.h"
  39 #include "scsi_logging.h"
  40
  41
  42 static int scsi_host_next_hn;           /* host_no for next new host */
  43
  44
  45 static void scsi_host_cls_release(struct class_device *class_dev)
  46 {
  47         put_device(&class_to_shost(class_dev)->shost_gendev);
  48 }
  49
  50 static struct class shost_class = {
  51         .name           = "scsi_host",
  52         .release        = scsi_host_cls_release,
  53 };
  54
  55 /**
  56  *      scsi_host_set_state - Take the given host through the host
  57  *              state model.
  58  *      @shost: scsi host to change the state of.
  59  *      @state: state to change to.
  60  *
  61  *      Returns zero if unsuccessful or an error if the requested
  62  *      transition is illegal.
  63  **/
  64 int scsi_host_set_state(struct Scsi_Host *shost, enum scsi_host_state state)
  65 {
  66         enum scsi_host_state oldstate = shost->shost_state;
  67
  68         if (state == oldstate)
  69                 return 0;
  70
  71         switch (state) {
  72         case SHOST_CREATED:
  73                 /* There are no legal states that come back to
  74                  * created.  This is the manually initialised start
  75                  * state */
  76                 goto illegal;
  77
  78         case SHOST_RUNNING:
  79                 switch (oldstate) {
  80                 case SHOST_CREATED:
  81                 case SHOST_RECOVERY:
  82                         break;
  83                 default:
  84                         goto illegal;
  85                 }
  86                 break;
  87
  88         case SHOST_RECOVERY:
  89                 switch (oldstate) {
  90                 case SHOST_RUNNING:
  91                         break;
  92                 default:
  93                         goto illegal;
  94                 }
  95                 break;
  96
  97         case SHOST_CANCEL:
  98                 switch (oldstate) {
  99                 case SHOST_CREATED:
 100                 case SHOST_RUNNING:
 101                 case SHOST_CANCEL_RECOVERY:
 102                         break;
 103                 default:
 104                         goto illegal;
 105                 }
 106                 break;
 107
 108         case SHOST_DEL:
 109                 switch (oldstate) {
 110                 case SHOST_CANCEL:
 111                 case SHOST_DEL_RECOVERY:
 112                         break;
 113                 default:
 114                         goto illegal;
 115                 }
 116                 break;
 117
 118         case SHOST_CANCEL_RECOVERY:
 119                 switch (oldstate) {
 120                 case SHOST_CANCEL:
 121                 case SHOST_RECOVERY:
 122                         break;
 123                 default:
 124                         goto illegal;
 125                 }
 126                 break;
 127
 128         case SHOST_DEL_RECOVERY:
 129                 switch (oldstate) {
 130                 case SHOST_CANCEL_RECOVERY:
 131                         break;
 132                 default:
 133                         goto illegal;
 134                 }
 135                 break;
 136         }
 137         shost->shost_state = state;
 138         return 0;
 139
 140  illegal:
 141         SCSI_LOG_ERROR_RECOVERY(1,
 142                                 dev_printk(KERN_ERR, &shost->shost_gendev,
 143                                            "Illegal host state transition"
 144                                            "%s->%s\n",
 145                                            scsi_host_state_name(oldstate),
 146                                            scsi_host_state_name(state)));
 147         return -EINVAL;
 148 }
 149 EXPORT_SYMBOL(scsi_host_set_state);
 150
 151 /**
 152  * scsi_remove_host - remove a scsi host
 153  * @shost:      a pointer to a scsi host to remove
 154  **/
 155 void scsi_remove_host(struct Scsi_Host *shost)
 156 {
 157         unsigned long flags;
 158         down(&shost->scan_mutex);
 159         spin_lock_irqsave(shost->host_lock, flags);
 160         if (scsi_host_set_state(shost, SHOST_CANCEL))
 161                 if (scsi_host_set_state(shost, SHOST_CANCEL_RECOVERY)) {
 162                         spin_unlock_irqrestore(shost->host_lock, flags);
 163                         up(&shost->scan_mutex);
 164                         return;
 165                 }
 166         spin_unlock_irqrestore(shost->host_lock, flags);
 167         up(&shost->scan_mutex);
 168         scsi_forget_host(shost);
 169         scsi_proc_host_rm(shost);
 170
 171         spin_lock_irqsave(shost->host_lock, flags);
 172         if (scsi_host_set_state(shost, SHOST_DEL))
 173                 BUG_ON(scsi_host_set_state(shost, SHOST_DEL_RECOVERY));
 174         spin_unlock_irqrestore(shost->host_lock, flags);
 175
 176         transport_unregister_device(&shost->shost_gendev);
 177         class_device_unregister(&shost->shost_classdev);
 178         device_del(&shost->shost_gendev);
 179         scsi_proc_hostdir_rm(shost->hostt);
 180 }
 181 EXPORT_SYMBOL(scsi_remove_host);
 182
 183 /**
 184  * scsi_add_host - add a scsi host
 185  * @shost:      scsi host pointer to add
 186  * @dev:        a struct device of type scsi class
 187  *
 188  * Return value:
 189  *      0 on success / != 0 for error
 190  **/
 191 int scsi_add_host(struct Scsi_Host *shost, struct device *dev)
 192 {
 193         struct scsi_host_template *sht = shost->hostt;
 194         int error = -EINVAL;
 195
 196         printk(KERN_INFO "scsi%d : %s\n", shost->host_no,
 197                         sht->info ? sht->info(shost) : sht->name);
 198
 199         if (!shost->can_queue) {
 200                 printk(KERN_ERR "%s: can_queue = 0 no longer supported\n",
 201                                 sht->name);
 202                 goto out;
 203         }
 204
 205         if (!shost->shost_gendev.parent)
 206                 shost->shost_gendev.parent = dev ? dev : &platform_bus;
 207
 208         error = device_add(&shost->shost_gendev);
 209         if (error)
 210                 goto out;
 211
 212         scsi_host_set_state(shost, SHOST_RUNNING);
 213         get_device(shost->shost_gendev.parent);
 214
 215         error = class_device_add(&shost->shost_classdev);
 216         if (error)
 217                 goto out_del_gendev;
 218
 219         get_device(&shost->shost_gendev);
 220
 221         if (shost->transportt->host_size &&
 222             (shost->shost_data = kmalloc(shost->transportt->host_size,
 223                                          GFP_KERNEL)) == NULL)
 224                 goto out_del_classdev;
 225
 226         if (shost->transportt->create_work_queue) {
 227                 snprintf(shost->work_q_name, KOBJ_NAME_LEN, "scsi_wq_%d",
 228                         shost->host_no);
 229                 shost->work_q = create_singlethread_workqueue(
 230                                         shost->work_q_name);
 231                 if (!shost->work_q)
 232                         goto out_free_shost_data;
 233         }
 234
 235         error = scsi_sysfs_add_host(shost);
 236         if (error)
 237                 goto out_destroy_host;
 238
 239         scsi_proc_host_add(shost);
 240         return error;
 241
 242  out_destroy_host:
 243         if (shost->work_q)
 244                 destroy_workqueue(shost->work_q);
 245  out_free_shost_data:
 246         kfree(shost->shost_data);
 247  out_del_classdev:
 248         class_device_del(&shost->shost_classdev);
 249  out_del_gendev:
 250         device_del(&shost->shost_gendev);
 251  out:
 252         return error;
 253 }
 254 EXPORT_SYMBOL(scsi_add_host);
 255
 256 static void scsi_host_dev_release(struct device *dev)
 257 {
 258         struct Scsi_Host *shost = dev_to_shost(dev);
 259         struct device *parent = dev->parent;
 260
 261         if (shost->ehandler)
 262                 kthread_stop(shost->ehandler);
 263         if (shost->work_q)
 264                 destroy_workqueue(shost->work_q);
 265
 266         scsi_destroy_command_freelist(shost);
 267         kfree(shost->shost_data);
 268
 269         if (parent)
 270                 put_device(parent);
 271         kfree(shost);
 272 }
 273
 274 /**
 275  * scsi_host_alloc - register a scsi host adapter instance.
 276  * @sht:        pointer to scsi host template
 277  * @privsize:   extra bytes to allocate for driver
 278  *
 279  * Note:
 280  *      Allocate a new Scsi_Host and perform basic initialization.
 281  *      The host is not published to the scsi midlayer until scsi_add_host
 282  *      is called.
 283  *
 284  * Return value:
 285  *      Pointer to a new Scsi_Host
 286  **/
 287 struct Scsi_Host *scsi_host_alloc(struct scsi_host_template *sht, int privsize)
 288 {
 289         struct Scsi_Host *shost;
 290         int gfp_mask = GFP_KERNEL, rval;
 291
 292         if (sht->unchecked_isa_dma && privsize)
 293                 gfp_mask |= __GFP_DMA;
 294
 295         /* Check to see if this host has any error handling facilities */
 296         if (!sht->eh_strategy_handler && !sht->eh_abort_handler &&
 297             !sht->eh_device_reset_handler && !sht->eh_bus_reset_handler &&
 298             !sht->eh_host_reset_handler) {
 299                 printk(KERN_ERR "ERROR: SCSI host `%s' has no error handling\n"
 300                                 "ERROR: This is not a safe way to run your "
 301                                         "SCSI host\n"
 302                                 "ERROR: The error handling must be added to "
 303                                 "this driver\n", sht->proc_name);
 304                 dump_stack();
 305         }
 306
 307         shost = kmalloc(sizeof(struct Scsi_Host) + privsize, gfp_mask);
 308         if (!shost)
 309                 return NULL;
 310         memset(shost, 0, sizeof(struct Scsi_Host) + privsize);
 311
 312         spin_lock_init(&shost->default_lock);
 313         scsi_assign_lock(shost, &shost->default_lock);
 314         shost->shost_state = SHOST_CREATED;
 315         INIT_LIST_HEAD(&shost->__devices);
 316         INIT_LIST_HEAD(&shost->__targets);
 317         INIT_LIST_HEAD(&shost->eh_cmd_q);
 318         INIT_LIST_HEAD(&shost->starved_list);
 319         init_waitqueue_head(&shost->host_wait);
 320
 321         init_MUTEX(&shost->scan_mutex);
 322
 323         shost->host_no = scsi_host_next_hn++; /* XXX(hch): still racy */
 324         shost->dma_channel = 0xff;
 325
 326         /* These three are default values which can be overridden */
 327         shost->max_channel = 0;
 328         shost->max_id = 8;
 329         shost->max_lun = 8;
 330
 331         /* Give each shost a default transportt */
 332         shost->transportt = &blank_transport_template;
 333
 334         /*
 335          * All drivers right now should be able to handle 12 byte
 336          * commands.  Every so often there are requests for 16 byte
 337          * commands, but individual low-level drivers need to certify that
 338          * they actually do something sensible with such commands.
 339          */
 340         shost->max_cmd_len = 12;
 341         shost->hostt = sht;
 342         shost->this_id = sht->this_id;
 343         shost->can_queue = sht->can_queue;
 344         shost->sg_tablesize = sht->sg_tablesize;
 345         shost->cmd_per_lun = sht->cmd_per_lun;
 346         shost->unchecked_isa_dma = sht->unchecked_isa_dma;
 347         shost->use_clustering = sht->use_clustering;
 348         shost->ordered_flush = sht->ordered_flush;
 349         shost->ordered_tag = sht->ordered_tag;
 350
 351         /*
 352          * hosts/devices that do queueing must support ordered tags
 353          */
 354         if (shost->can_queue > 1 && shost->ordered_flush) {
 355                 printk(KERN_ERR "scsi: ordered flushes don't support queueing\n");
 356                 shost->ordered_flush = 0;
 357         }
 358
 359         if (sht->max_host_blocked)
 360                 shost->max_host_blocked = sht->max_host_blocked;
 361         else
 362                 shost->max_host_blocked = SCSI_DEFAULT_HOST_BLOCKED;
 363
 364         /*
 365          * If the driver imposes no hard sector transfer limit, start at
 366          * machine infinity initially.
 367          */
 368         if (sht->max_sectors)
 369                 shost->max_sectors = sht->max_sectors;
 370         else
 371                 shost->max_sectors = SCSI_DEFAULT_MAX_SECTORS;
 372
 373         /*
 374          * assume a 4GB boundary, if not set
 375          */
 376         if (sht->dma_boundary)
 377                 shost->dma_boundary = sht->dma_boundary;
 378         else
 379                 shost->dma_boundary = 0xffffffff;
 380
 381         rval = scsi_setup_command_freelist(shost);
 382         if (rval)
 383                 goto fail_kfree;
 384
 385         device_initialize(&shost->shost_gendev);
 386         snprintf(shost->shost_gendev.bus_id, BUS_ID_SIZE, "host%d",
 387                 shost->host_no);
 388         shost->shost_gendev.release = scsi_host_dev_release;
 389
 390         class_device_initialize(&shost->shost_classdev);
 391         shost->shost_classdev.dev = &shost->shost_gendev;
 392         shost->shost_classdev.class = &shost_class;
 393         snprintf(shost->shost_classdev.class_id, BUS_ID_SIZE, "host%d",
 394                   shost->host_no);
 395
 396         shost->ehandler = kthread_run(scsi_error_handler, shost,
 397                         "scsi_eh_%d", shost->host_no);
 398         if (IS_ERR(shost->ehandler)) {
 399                 rval = PTR_ERR(shost->ehandler);
 400                 goto fail_destroy_freelist;
 401         }
 402
 403         scsi_proc_hostdir_add(shost->hostt);
 404         return shost;
 405
 406  fail_destroy_freelist:
 407         scsi_destroy_command_freelist(shost);
 408  fail_kfree:
 409         kfree(shost);
 410         return NULL;
 411 }
 412 EXPORT_SYMBOL(scsi_host_alloc);
 413
 414 struct Scsi_Host *scsi_register(struct scsi_host_template *sht, int privsize)
 415 {
 416         struct Scsi_Host *shost = scsi_host_alloc(sht, privsize);
 417
 418         if (!sht->detect) {
 419                 printk(KERN_WARNING "scsi_register() called on new-style "
 420                                     "template for driver %s\n", sht->name);
 421                 dump_stack();
 422         }
 423
 424         if (shost)
 425                 list_add_tail(&shost->sht_legacy_list, &sht->legacy_hosts);
 426         return shost;
 427 }
 428 EXPORT_SYMBOL(scsi_register);
 429
 430 void scsi_unregister(struct Scsi_Host *shost)
 431 {
 432         list_del(&shost->sht_legacy_list);
 433         scsi_host_put(shost);
 434 }
 435 EXPORT_SYMBOL(scsi_unregister);
 436
 437 /**
 438  * scsi_host_lookup - get a reference to a Scsi_Host by host no
 439  *
 440  * @hostnum:    host number to locate
 441  *
 442  * Return value:
 443  *      A pointer to located Scsi_Host or NULL.
 444  **/
 445 struct Scsi_Host *scsi_host_lookup(unsigned short hostnum)
 446 {
 447         struct class *class = &shost_class;
 448         struct class_device *cdev;
 449         struct Scsi_Host *shost = ERR_PTR(-ENXIO), *p;
 450
 451         down_read(&class->subsys.rwsem);
 452         list_for_each_entry(cdev, &class->children, node) {
 453                 p = class_to_shost(cdev);
 454                 if (p->host_no == hostnum) {
 455                         shost = scsi_host_get(p);
 456                         break;
 457                 }
 458         }
 459         up_read(&class->subsys.rwsem);
 460
 461         return shost;
 462 }
 463 EXPORT_SYMBOL(scsi_host_lookup);
 464
 465 /**
 466  * scsi_host_get - inc a Scsi_Host ref count
 467  * @shost:      Pointer to Scsi_Host to inc.
 468  **/
 469 struct Scsi_Host *scsi_host_get(struct Scsi_Host *shost)
 470 {
 471         if ((shost->shost_state == SHOST_DEL) ||
 472                 !get_device(&shost->shost_gendev))
 473                 return NULL;
 474         return shost;
 475 }
 476 EXPORT_SYMBOL(scsi_host_get);
 477
 478 /**
 479  * scsi_host_put - dec a Scsi_Host ref count
 480  * @shost:      Pointer to Scsi_Host to dec.
 481  **/
 482 void scsi_host_put(struct Scsi_Host *shost)
 483 {
 484         put_device(&shost->shost_gendev);
 485 }
 486 EXPORT_SYMBOL(scsi_host_put);
 487
 488 int scsi_init_hosts(void)
 489 {
 490         return class_register(&shost_class);
 491 }
 492
 493 void scsi_exit_hosts(void)
 494 {
 495         class_unregister(&shost_class);
 496 }
 497
 498 int scsi_is_host_device(const struct device *dev)
 499 {
 500         return dev->release == scsi_host_dev_release;
 501 }
 502 EXPORT_SYMBOL(scsi_is_host_device);
 503
 504 /**
 505  * scsi_queue_work - Queue work to the Scsi_Host workqueue.
 506  * @shost:      Pointer to Scsi_Host.
 507  * @work:       Work to queue for execution.
 508  *
 509  * Return value:
 510  *      0 on success / != 0 for error
 511  **/
 512 int scsi_queue_work(struct Scsi_Host *shost, struct work_struct *work)
 513 {
 514         if (unlikely(!shost->work_q)) {
 515                 printk(KERN_ERR
 516                         "ERROR: Scsi host '%s' attempted to queue scsi-work, "
 517                         "when no workqueue created.\n", shost->hostt->name);
 518                 dump_stack();
 519
 520                 return -EINVAL;
 521         }
 522
 523         return queue_work(shost->work_q, work);
 524 }
 525 EXPORT_SYMBOL_GPL(scsi_queue_work);
 526
 527 /**
 528  * scsi_flush_work - Flush a Scsi_Host's workqueue.
 529  * @shost:      Pointer to Scsi_Host.
 530  **/
 531 void scsi_flush_work(struct Scsi_Host *shost)
 532 {
 533         if (!shost->work_q) {
 534                 printk(KERN_ERR
 535                         "ERROR: Scsi host '%s' attempted to flush scsi-work, "
 536                         "when no workqueue created.\n", shost->hostt->name);
 537                 dump_stack();
 538                 return;
 539         }
 540
 541         flush_workqueue(shost->work_q);
 542 }
 543 EXPORT_SYMBOL_GPL(scsi_flush_work);