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/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 #include <linux/platform_device.h>
  34
  35 #include <scsi/scsi_device.h>
  36 #include <scsi/scsi_host.h>
  37 #include <scsi/scsi_transport.h>
  38
  39 #include "scsi_priv.h"
  40 #include "scsi_logging.h"
  41
  42
  43 static atomic_t scsi_host_next_hn;      /* host_no for next new host */
  44
  45
  46 static void scsi_host_cls_release(struct device *dev)
  47 {
  48         put_device(&class_to_shost(dev)->shost_gendev);
  49 }
  50
  51 static struct class shost_class = {
  52         .name           = "scsi_host",
  53         .dev_release    = scsi_host_cls_release,
  54 };
  55
  56 /**
  57  *      scsi_host_set_state - Take the given host through the host 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                                 shost_printk(KERN_ERR, shost,
 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         mutex_lock(&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                         mutex_unlock(&shost->scan_mutex);
 164                         return;
 165                 }
 166         spin_unlock_irqrestore(shost->host_lock, flags);
 167         scsi_forget_host(shost);
 168         mutex_unlock(&shost->scan_mutex);
 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         device_unregister(&shost->shost_dev);
 178         device_del(&shost->shost_gendev);
 179 }
 180 EXPORT_SYMBOL(scsi_remove_host);
 181
 182 /**
 183  * scsi_add_host_with_dma - add a scsi host with dma device
 184  * @shost:      scsi host pointer to add
 185  * @dev:        a struct device of type scsi class
 186  * @dma_dev:    dma device for the host
 187  *
 188  * Note: You rarely need to worry about this unless you're in a
 189  * virtualised host environments, so use the simpler scsi_add_host()
 190  * function instead.
 191  *
 192  * Return value:
 193  *      0 on success / != 0 for error
 194  **/
 195 int scsi_add_host_with_dma(struct Scsi_Host *shost, struct device *dev,
 196                            struct device *dma_dev)
 197 {
 198         struct scsi_host_template *sht = shost->hostt;
 199         int error = -EINVAL;
 200
 201         printk(KERN_INFO "scsi%d : %s\n", shost->host_no,
 202                         sht->info ? sht->info(shost) : sht->name);
 203
 204         if (!shost->can_queue) {
 205                 printk(KERN_ERR "%s: can_queue = 0 no longer supported\n",
 206                                 sht->name);
 207                 goto fail;
 208         }
 209
 210         error = scsi_setup_command_freelist(shost);
 211         if (error)
 212                 goto fail;
 213
 214         if (!shost->shost_gendev.parent)
 215                 shost->shost_gendev.parent = dev ? dev : &platform_bus;
 216         shost->dma_dev = dma_dev;
 217
 218         device_enable_async_suspend(&shost->shost_gendev);
 219
 220         error = device_add(&shost->shost_gendev);
 221         if (error)
 222                 goto out;
 223
 224         scsi_host_set_state(shost, SHOST_RUNNING);
 225         get_device(shost->shost_gendev.parent);
 226
 227         device_enable_async_suspend(&shost->shost_dev);
 228
 229         error = device_add(&shost->shost_dev);
 230         if (error)
 231                 goto out_del_gendev;
 232
 233         get_device(&shost->shost_gendev);
 234
 235         if (shost->transportt->host_size) {
 236                 shost->shost_data = kzalloc(shost->transportt->host_size,
 237                                          GFP_KERNEL);
 238                 if (shost->shost_data == NULL) {
 239                         error = -ENOMEM;
 240                         goto out_del_dev;
 241                 }
 242         }
 243
 244         if (shost->transportt->create_work_queue) {
 245                 snprintf(shost->work_q_name, sizeof(shost->work_q_name),
 246                          "scsi_wq_%d", shost->host_no);
 247                 shost->work_q = create_singlethread_workqueue(
 248                                         shost->work_q_name);
 249                 if (!shost->work_q) {
 250                         error = -EINVAL;
 251                         goto out_free_shost_data;
 252                 }
 253         }
 254
 255         error = scsi_sysfs_add_host(shost);
 256         if (error)
 257                 goto out_destroy_host;
 258
 259         scsi_proc_host_add(shost);
 260         return error;
 261
 262  out_destroy_host:
 263         if (shost->work_q)
 264                 destroy_workqueue(shost->work_q);
 265  out_free_shost_data:
 266         kfree(shost->shost_data);
 267  out_del_dev:
 268         device_del(&shost->shost_dev);
 269  out_del_gendev:
 270         device_del(&shost->shost_gendev);
 271  out:
 272         scsi_destroy_command_freelist(shost);
 273  fail:
 274         return error;
 275 }
 276 EXPORT_SYMBOL(scsi_add_host_with_dma);
 277
 278 static void scsi_host_dev_release(struct device *dev)
 279 {
 280         struct Scsi_Host *shost = dev_to_shost(dev);
 281         struct device *parent = dev->parent;
 282
 283         scsi_proc_hostdir_rm(shost->hostt);
 284
 285         if (shost->ehandler)
 286                 kthread_stop(shost->ehandler);
 287         if (shost->work_q)
 288                 destroy_workqueue(shost->work_q);
 289         if (shost->uspace_req_q) {
 290                 kfree(shost->uspace_req_q->queuedata);
 291                 scsi_free_queue(shost->uspace_req_q);
 292         }
 293
 294         scsi_destroy_command_freelist(shost);
 295         if (shost->bqt)
 296                 blk_free_tags(shost->bqt);
 297
 298         kfree(shost->shost_data);
 299
 300         if (parent)
 301                 put_device(parent);
 302         kfree(shost);
 303 }
 304
 305 static struct device_type scsi_host_type = {
 306         .name =         "scsi_host",
 307         .release =      scsi_host_dev_release,
 308 };
 309
 310 /**
 311  * scsi_host_alloc - register a scsi host adapter instance.
 312  * @sht:        pointer to scsi host template
 313  * @privsize:   extra bytes to allocate for driver
 314  *
 315  * Note:
 316  *      Allocate a new Scsi_Host and perform basic initialization.
 317  *      The host is not published to the scsi midlayer until scsi_add_host
 318  *      is called.
 319  *
 320  * Return value:
 321  *      Pointer to a new Scsi_Host
 322  **/
 323 struct Scsi_Host *scsi_host_alloc(struct scsi_host_template *sht, int privsize)
 324 {
 325         struct Scsi_Host *shost;
 326         gfp_t gfp_mask = GFP_KERNEL;
 327         int rval;
 328
 329         if (sht->unchecked_isa_dma && privsize)
 330                 gfp_mask |= __GFP_DMA;
 331
 332         shost = kzalloc(sizeof(struct Scsi_Host) + privsize, gfp_mask);
 333         if (!shost)
 334                 return NULL;
 335
 336         shost->host_lock = &shost->default_lock;
 337         spin_lock_init(shost->host_lock);
 338         shost->shost_state = SHOST_CREATED;
 339         INIT_LIST_HEAD(&shost->__devices);
 340         INIT_LIST_HEAD(&shost->__targets);
 341         INIT_LIST_HEAD(&shost->eh_cmd_q);
 342         INIT_LIST_HEAD(&shost->starved_list);
 343         init_waitqueue_head(&shost->host_wait);
 344
 345         mutex_init(&shost->scan_mutex);
 346
 347         /*
 348          * subtract one because we increment first then return, but we need to
 349          * know what the next host number was before increment
 350          */
 351         shost->host_no = atomic_inc_return(&scsi_host_next_hn) - 1;
 352         shost->dma_channel = 0xff;
 353
 354         /* These three are default values which can be overridden */
 355         shost->max_channel = 0;
 356         shost->max_id = 8;
 357         shost->max_lun = 8;
 358
 359         /* Give each shost a default transportt */
 360         shost->transportt = &blank_transport_template;
 361
 362         /*
 363          * All drivers right now should be able to handle 12 byte
 364          * commands.  Every so often there are requests for 16 byte
 365          * commands, but individual low-level drivers need to certify that
 366          * they actually do something sensible with such commands.
 367          */
 368         shost->max_cmd_len = 12;
 369         shost->hostt = sht;
 370         shost->this_id = sht->this_id;
 371         shost->can_queue = sht->can_queue;
 372         shost->sg_tablesize = sht->sg_tablesize;
 373         shost->cmd_per_lun = sht->cmd_per_lun;
 374         shost->unchecked_isa_dma = sht->unchecked_isa_dma;
 375         shost->use_clustering = sht->use_clustering;
 376         shost->ordered_tag = sht->ordered_tag;
 377
 378         if (sht->supported_mode == MODE_UNKNOWN)
 379                 /* means we didn't set it ... default to INITIATOR */
 380                 shost->active_mode = MODE_INITIATOR;
 381         else
 382                 shost->active_mode = sht->supported_mode;
 383
 384         if (sht->max_host_blocked)
 385                 shost->max_host_blocked = sht->max_host_blocked;
 386         else
 387                 shost->max_host_blocked = SCSI_DEFAULT_HOST_BLOCKED;
 388
 389         /*
 390          * If the driver imposes no hard sector transfer limit, start at
 391          * machine infinity initially.
 392          */
 393         if (sht->max_sectors)
 394                 shost->max_sectors = sht->max_sectors;
 395         else
 396                 shost->max_sectors = SCSI_DEFAULT_MAX_SECTORS;
 397
 398         /*
 399          * assume a 4GB boundary, if not set
 400          */
 401         if (sht->dma_boundary)
 402                 shost->dma_boundary = sht->dma_boundary;
 403         else
 404                 shost->dma_boundary = 0xffffffff;
 405
 406         device_initialize(&shost->shost_gendev);
 407         dev_set_name(&shost->shost_gendev, "host%d", shost->host_no);
 408 #ifndef CONFIG_SYSFS_DEPRECATED
 409         shost->shost_gendev.bus = &scsi_bus_type;
 410 #endif
 411         shost->shost_gendev.type = &scsi_host_type;
 412
 413         device_initialize(&shost->shost_dev);
 414         shost->shost_dev.parent = &shost->shost_gendev;
 415         shost->shost_dev.class = &shost_class;
 416         dev_set_name(&shost->shost_dev, "host%d", shost->host_no);
 417         shost->shost_dev.groups = scsi_sysfs_shost_attr_groups;
 418
 419         shost->ehandler = kthread_run(scsi_error_handler, shost,
 420                         "scsi_eh_%d", shost->host_no);
 421         if (IS_ERR(shost->ehandler)) {
 422                 rval = PTR_ERR(shost->ehandler);
 423                 goto fail_kfree;
 424         }
 425
 426         scsi_proc_hostdir_add(shost->hostt);
 427         return shost;
 428
 429  fail_kfree:
 430         kfree(shost);
 431         return NULL;
 432 }
 433 EXPORT_SYMBOL(scsi_host_alloc);
 434
 435 struct Scsi_Host *scsi_register(struct scsi_host_template *sht, int privsize)
 436 {
 437         struct Scsi_Host *shost = scsi_host_alloc(sht, privsize);
 438
 439         if (!sht->detect) {
 440                 printk(KERN_WARNING "scsi_register() called on new-style "
 441                                     "template for driver %s\n", sht->name);
 442                 dump_stack();
 443         }
 444
 445         if (shost)
 446                 list_add_tail(&shost->sht_legacy_list, &sht->legacy_hosts);
 447         return shost;
 448 }
 449 EXPORT_SYMBOL(scsi_register);
 450
 451 void scsi_unregister(struct Scsi_Host *shost)
 452 {
 453         list_del(&shost->sht_legacy_list);
 454         scsi_host_put(shost);
 455 }
 456 EXPORT_SYMBOL(scsi_unregister);
 457
 458 static int __scsi_host_match(struct device *dev, void *data)
 459 {
 460         struct Scsi_Host *p;
 461         unsigned short *hostnum = (unsigned short *)data;
 462
 463         p = class_to_shost(dev);
 464         return p->host_no == *hostnum;
 465 }
 466
 467 /**
 468  * scsi_host_lookup - get a reference to a Scsi_Host by host no
 469  * @hostnum:    host number to locate
 470  *
 471  * Return value:
 472  *      A pointer to located Scsi_Host or NULL.
 473  *
 474  *      The caller must do a scsi_host_put() to drop the reference
 475  *      that scsi_host_get() took. The put_device() below dropped
 476  *      the reference from class_find_device().
 477  **/
 478 struct Scsi_Host *scsi_host_lookup(unsigned short hostnum)
 479 {
 480         struct device *cdev;
 481         struct Scsi_Host *shost = NULL;
 482
 483         cdev = class_find_device(&shost_class, NULL, &hostnum,
 484                                  __scsi_host_match);
 485         if (cdev) {
 486                 shost = scsi_host_get(class_to_shost(cdev));
 487                 put_device(cdev);
 488         }
 489         return shost;
 490 }
 491 EXPORT_SYMBOL(scsi_host_lookup);
 492
 493 /**
 494  * scsi_host_get - inc a Scsi_Host ref count
 495  * @shost:      Pointer to Scsi_Host to inc.
 496  **/
 497 struct Scsi_Host *scsi_host_get(struct Scsi_Host *shost)
 498 {
 499         if ((shost->shost_state == SHOST_DEL) ||
 500                 !get_device(&shost->shost_gendev))
 501                 return NULL;
 502         return shost;
 503 }
 504 EXPORT_SYMBOL(scsi_host_get);
 505
 506 /**
 507  * scsi_host_put - dec a Scsi_Host ref count
 508  * @shost:      Pointer to Scsi_Host to dec.
 509  **/
 510 void scsi_host_put(struct Scsi_Host *shost)
 511 {
 512         put_device(&shost->shost_gendev);
 513 }
 514 EXPORT_SYMBOL(scsi_host_put);
 515
 516 int scsi_init_hosts(void)
 517 {
 518         return class_register(&shost_class);
 519 }
 520
 521 void scsi_exit_hosts(void)
 522 {
 523         class_unregister(&shost_class);
 524 }
 525
 526 int scsi_is_host_device(const struct device *dev)
 527 {
 528         return dev->type == &scsi_host_type;
 529 }
 530 EXPORT_SYMBOL(scsi_is_host_device);
 531
 532 /**
 533  * scsi_queue_work - Queue work to the Scsi_Host workqueue.
 534  * @shost:      Pointer to Scsi_Host.
 535  * @work:       Work to queue for execution.
 536  *
 537  * Return value:
 538  *      1 - work queued for execution
 539  *      0 - work is already queued
 540  *      -EINVAL - work queue doesn't exist
 541  **/
 542 int scsi_queue_work(struct Scsi_Host *shost, struct work_struct *work)
 543 {
 544         if (unlikely(!shost->work_q)) {
 545                 printk(KERN_ERR
 546                         "ERROR: Scsi host '%s' attempted to queue scsi-work, "
 547                         "when no workqueue created.\n", shost->hostt->name);
 548                 dump_stack();
 549
 550                 return -EINVAL;
 551         }
 552
 553         return queue_work(shost->work_q, work);
 554 }
 555 EXPORT_SYMBOL_GPL(scsi_queue_work);
 556
 557 /**
 558  * scsi_flush_work - Flush a Scsi_Host's workqueue.
 559  * @shost:      Pointer to Scsi_Host.
 560  **/
 561 void scsi_flush_work(struct Scsi_Host *shost)
 562 {
 563         if (!shost->work_q) {
 564                 printk(KERN_ERR
 565                         "ERROR: Scsi host '%s' attempted to flush scsi-work, "
 566                         "when no workqueue created.\n", shost->hostt->name);
 567                 dump_stack();
 568                 return;
 569         }
 570
 571         flush_workqueue(shost->work_q);
 572 }
 573 EXPORT_SYMBOL_GPL(scsi_flush_work);