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
  36 #include <scsi/scsi_device.h>
  37 #include <scsi/scsi_host.h>
  38 #include <scsi/scsi_transport.h>
  39
  40 #include "scsi_priv.h"
  41 #include "scsi_logging.h"
  42
  43
  44 static atomic_t scsi_host_next_hn;      /* host_no for next new host */
  45
  46
  47 static void scsi_host_cls_release(struct device *dev)
  48 {
  49         put_device(&class_to_shost(dev)->shost_gendev);
  50 }
  51
  52 static struct class shost_class = {
  53         .name           = "scsi_host",
  54         .dev_release    = scsi_host_cls_release,
  55 };
  56
  57 /**
  58  *      scsi_host_set_state - Take the given host through the host state model.
  59  *      @shost: scsi host to change the state of.
  60  *      @state: state to change to.
  61  *
  62  *      Returns zero if unsuccessful or an error if the requested
  63  *      transition is illegal.
  64  **/
  65 int scsi_host_set_state(struct Scsi_Host *shost, enum scsi_host_state state)
  66 {
  67         enum scsi_host_state oldstate = shost->shost_state;
  68
  69         if (state == oldstate)
  70                 return 0;
  71
  72         switch (state) {
  73         case SHOST_CREATED:
  74                 /* There are no legal states that come back to
  75                  * created.  This is the manually initialised start
  76                  * state */
  77                 goto illegal;
  78
  79         case SHOST_RUNNING:
  80                 switch (oldstate) {
  81                 case SHOST_CREATED:
  82                 case SHOST_RECOVERY:
  83                         break;
  84                 default:
  85                         goto illegal;
  86                 }
  87                 break;
  88
  89         case SHOST_RECOVERY:
  90                 switch (oldstate) {
  91                 case SHOST_RUNNING:
  92                         break;
  93                 default:
  94                         goto illegal;
  95                 }
  96                 break;
  97
  98         case SHOST_CANCEL:
  99                 switch (oldstate) {
 100                 case SHOST_CREATED:
 101                 case SHOST_RUNNING:
 102                 case SHOST_CANCEL_RECOVERY:
 103                         break;
 104                 default:
 105                         goto illegal;
 106                 }
 107                 break;
 108
 109         case SHOST_DEL:
 110                 switch (oldstate) {
 111                 case SHOST_CANCEL:
 112                 case SHOST_DEL_RECOVERY:
 113                         break;
 114                 default:
 115                         goto illegal;
 116                 }
 117                 break;
 118
 119         case SHOST_CANCEL_RECOVERY:
 120                 switch (oldstate) {
 121                 case SHOST_CANCEL:
 122                 case SHOST_RECOVERY:
 123                         break;
 124                 default:
 125                         goto illegal;
 126                 }
 127                 break;
 128
 129         case SHOST_DEL_RECOVERY:
 130                 switch (oldstate) {
 131                 case SHOST_CANCEL_RECOVERY:
 132                         break;
 133                 default:
 134                         goto illegal;
 135                 }
 136                 break;
 137         }
 138         shost->shost_state = state;
 139         return 0;
 140
 141  illegal:
 142         SCSI_LOG_ERROR_RECOVERY(1,
 143                                 shost_printk(KERN_ERR, shost,
 144                                              "Illegal host state transition"
 145                                              "%s->%s\n",
 146                                              scsi_host_state_name(oldstate),
 147                                              scsi_host_state_name(state)));
 148         return -EINVAL;
 149 }
 150 EXPORT_SYMBOL(scsi_host_set_state);
 151
 152 /**
 153  * scsi_remove_host - remove a scsi host
 154  * @shost:      a pointer to a scsi host to remove
 155  **/
 156 void scsi_remove_host(struct Scsi_Host *shost)
 157 {
 158         unsigned long flags;
 159         mutex_lock(&shost->scan_mutex);
 160         spin_lock_irqsave(shost->host_lock, flags);
 161         if (scsi_host_set_state(shost, SHOST_CANCEL))
 162                 if (scsi_host_set_state(shost, SHOST_CANCEL_RECOVERY)) {
 163                         spin_unlock_irqrestore(shost->host_lock, flags);
 164                         mutex_unlock(&shost->scan_mutex);
 165                         return;
 166                 }
 167         spin_unlock_irqrestore(shost->host_lock, flags);
 168         scsi_forget_host(shost);
 169         mutex_unlock(&shost->scan_mutex);
 170         scsi_proc_host_rm(shost);
 171
 172         spin_lock_irqsave(shost->host_lock, flags);
 173         if (scsi_host_set_state(shost, SHOST_DEL))
 174                 BUG_ON(scsi_host_set_state(shost, SHOST_DEL_RECOVERY));
 175         spin_unlock_irqrestore(shost->host_lock, flags);
 176
 177         transport_unregister_device(&shost->shost_gendev);
 178         device_unregister(&shost->shost_dev);
 179         device_del(&shost->shost_gendev);
 180 }
 181 EXPORT_SYMBOL(scsi_remove_host);
 182
 183 /**
 184  * scsi_add_host_with_dma - add a scsi host with dma device
 185  * @shost:      scsi host pointer to add
 186  * @dev:        a struct device of type scsi class
 187  * @dma_dev:    dma device for the host
 188  *
 189  * Note: You rarely need to worry about this unless you're in a
 190  * virtualised host environments, so use the simpler scsi_add_host()
 191  * function instead.
 192  *
 193  * Return value:
 194  *      0 on success / != 0 for error
 195  **/
 196 int scsi_add_host_with_dma(struct Scsi_Host *shost, struct device *dev,
 197                            struct device *dma_dev)
 198 {
 199         struct scsi_host_template *sht = shost->hostt;
 200         int error = -EINVAL;
 201
 202         printk(KERN_INFO "scsi%d : %s\n", shost->host_no,
 203                         sht->info ? sht->info(shost) : sht->name);
 204
 205         if (!shost->can_queue) {
 206                 printk(KERN_ERR "%s: can_queue = 0 no longer supported\n",
 207                                 sht->name);
 208                 goto fail;
 209         }
 210
 211         error = scsi_setup_command_freelist(shost);
 212         if (error)
 213                 goto fail;
 214
 215         if (!shost->shost_gendev.parent)
 216                 shost->shost_gendev.parent = dev ? dev : &platform_bus;
 217         shost->dma_dev = dma_dev;
 218
 219         device_enable_async_suspend(&shost->shost_gendev);
 220
 221         error = device_add(&shost->shost_gendev);
 222         if (error)
 223                 goto out;
 224
 225         scsi_host_set_state(shost, SHOST_RUNNING);
 226         get_device(shost->shost_gendev.parent);
 227
 228         device_enable_async_suspend(&shost->shost_dev);
 229
 230         error = device_add(&shost->shost_dev);
 231         if (error)
 232                 goto out_del_gendev;
 233
 234         get_device(&shost->shost_gendev);
 235
 236         if (shost->transportt->host_size) {
 237                 shost->shost_data = kzalloc(shost->transportt->host_size,
 238                                          GFP_KERNEL);
 239                 if (shost->shost_data == NULL) {
 240                         error = -ENOMEM;
 241                         goto out_del_dev;
 242                 }
 243         }
 244
 245         if (shost->transportt->create_work_queue) {
 246                 snprintf(shost->work_q_name, sizeof(shost->work_q_name),
 247                          "scsi_wq_%d", shost->host_no);
 248                 shost->work_q = create_singlethread_workqueue(
 249                                         shost->work_q_name);
 250                 if (!shost->work_q) {
 251                         error = -EINVAL;
 252                         goto out_free_shost_data;
 253                 }
 254         }
 255
 256         error = scsi_sysfs_add_host(shost);
 257         if (error)
 258                 goto out_destroy_host;
 259
 260         scsi_proc_host_add(shost);
 261         return error;
 262
 263  out_destroy_host:
 264         if (shost->work_q)
 265                 destroy_workqueue(shost->work_q);
 266  out_free_shost_data:
 267         kfree(shost->shost_data);
 268  out_del_dev:
 269         device_del(&shost->shost_dev);
 270  out_del_gendev:
 271         device_del(&shost->shost_gendev);
 272  out:
 273         scsi_destroy_command_freelist(shost);
 274  fail:
 275         return error;
 276 }
 277 EXPORT_SYMBOL(scsi_add_host_with_dma);
 278
 279 static void scsi_host_dev_release(struct device *dev)
 280 {
 281         struct Scsi_Host *shost = dev_to_shost(dev);
 282         struct device *parent = dev->parent;
 283
 284         scsi_proc_hostdir_rm(shost->hostt);
 285
 286         if (shost->ehandler)
 287                 kthread_stop(shost->ehandler);
 288         if (shost->work_q)
 289                 destroy_workqueue(shost->work_q);
 290         if (shost->uspace_req_q) {
 291                 kfree(shost->uspace_req_q->queuedata);
 292                 scsi_free_queue(shost->uspace_req_q);
 293         }
 294
 295         scsi_destroy_command_freelist(shost);
 296         if (shost->bqt)
 297                 blk_free_tags(shost->bqt);
 298
 299         kfree(shost->shost_data);
 300
 301         if (parent)
 302                 put_device(parent);
 303         kfree(shost);
 304 }
 305
 306 static struct device_type scsi_host_type = {
 307         .name =         "scsi_host",
 308         .release =      scsi_host_dev_release,
 309 };
 310
 311 /**
 312  * scsi_host_alloc - register a scsi host adapter instance.
 313  * @sht:        pointer to scsi host template
 314  * @privsize:   extra bytes to allocate for driver
 315  *
 316  * Note:
 317  *      Allocate a new Scsi_Host and perform basic initialization.
 318  *      The host is not published to the scsi midlayer until scsi_add_host
 319  *      is called.
 320  *
 321  * Return value:
 322  *      Pointer to a new Scsi_Host
 323  **/
 324 struct Scsi_Host *scsi_host_alloc(struct scsi_host_template *sht, int privsize)
 325 {
 326         struct Scsi_Host *shost;
 327         gfp_t gfp_mask = GFP_KERNEL;
 328         int rval;
 329
 330         if (sht->unchecked_isa_dma && privsize)
 331                 gfp_mask |= __GFP_DMA;
 332
 333         shost = kzalloc(sizeof(struct Scsi_Host) + privsize, gfp_mask);
 334         if (!shost)
 335                 return NULL;
 336
 337         shost->host_lock = &shost->default_lock;
 338         spin_lock_init(shost->host_lock);
 339         shost->shost_state = SHOST_CREATED;
 340         INIT_LIST_HEAD(&shost->__devices);
 341         INIT_LIST_HEAD(&shost->__targets);
 342         INIT_LIST_HEAD(&shost->eh_cmd_q);
 343         INIT_LIST_HEAD(&shost->starved_list);
 344         init_waitqueue_head(&shost->host_wait);
 345
 346         mutex_init(&shost->scan_mutex);
 347
 348         /*
 349          * subtract one because we increment first then return, but we need to
 350          * know what the next host number was before increment
 351          */
 352         shost->host_no = atomic_inc_return(&scsi_host_next_hn) - 1;
 353         shost->dma_channel = 0xff;
 354
 355         /* These three are default values which can be overridden */
 356         shost->max_channel = 0;
 357         shost->max_id = 8;
 358         shost->max_lun = 8;
 359
 360         /* Give each shost a default transportt */
 361         shost->transportt = &blank_transport_template;
 362
 363         /*
 364          * All drivers right now should be able to handle 12 byte
 365          * commands.  Every so often there are requests for 16 byte
 366          * commands, but individual low-level drivers need to certify that
 367          * they actually do something sensible with such commands.
 368          */
 369         shost->max_cmd_len = 12;
 370         shost->hostt = sht;
 371         shost->this_id = sht->this_id;
 372         shost->can_queue = sht->can_queue;
 373         shost->sg_tablesize = sht->sg_tablesize;
 374         shost->cmd_per_lun = sht->cmd_per_lun;
 375         shost->unchecked_isa_dma = sht->unchecked_isa_dma;
 376         shost->use_clustering = sht->use_clustering;
 377         shost->ordered_tag = sht->ordered_tag;
 378
 379         if (sht->supported_mode == MODE_UNKNOWN)
 380                 /* means we didn't set it ... default to INITIATOR */
 381                 shost->active_mode = MODE_INITIATOR;
 382         else
 383                 shost->active_mode = sht->supported_mode;
 384
 385         if (sht->max_host_blocked)
 386                 shost->max_host_blocked = sht->max_host_blocked;
 387         else
 388                 shost->max_host_blocked = SCSI_DEFAULT_HOST_BLOCKED;
 389
 390         /*
 391          * If the driver imposes no hard sector transfer limit, start at
 392          * machine infinity initially.
 393          */
 394         if (sht->max_sectors)
 395                 shost->max_sectors = sht->max_sectors;
 396         else
 397                 shost->max_sectors = SCSI_DEFAULT_MAX_SECTORS;
 398
 399         /*
 400          * assume a 4GB boundary, if not set
 401          */
 402         if (sht->dma_boundary)
 403                 shost->dma_boundary = sht->dma_boundary;
 404         else
 405                 shost->dma_boundary = 0xffffffff;
 406
 407         device_initialize(&shost->shost_gendev);
 408         dev_set_name(&shost->shost_gendev, "host%d", shost->host_no);
 409 #ifndef CONFIG_SYSFS_DEPRECATED
 410         shost->shost_gendev.bus = &scsi_bus_type;
 411 #endif
 412         shost->shost_gendev.type = &scsi_host_type;
 413
 414         device_initialize(&shost->shost_dev);
 415         shost->shost_dev.parent = &shost->shost_gendev;
 416         shost->shost_dev.class = &shost_class;
 417         dev_set_name(&shost->shost_dev, "host%d", shost->host_no);
 418         shost->shost_dev.groups = scsi_sysfs_shost_attr_groups;
 419
 420         shost->ehandler = kthread_run(scsi_error_handler, shost,
 421                         "scsi_eh_%d", shost->host_no);
 422         if (IS_ERR(shost->ehandler)) {
 423                 rval = PTR_ERR(shost->ehandler);
 424                 goto fail_kfree;
 425         }
 426
 427         scsi_proc_hostdir_add(shost->hostt);
 428         return shost;
 429
 430  fail_kfree:
 431         kfree(shost);
 432         return NULL;
 433 }
 434 EXPORT_SYMBOL(scsi_host_alloc);
 435
 436 struct Scsi_Host *scsi_register(struct scsi_host_template *sht, int privsize)
 437 {
 438         struct Scsi_Host *shost = scsi_host_alloc(sht, privsize);
 439
 440         if (!sht->detect) {
 441                 printk(KERN_WARNING "scsi_register() called on new-style "
 442                                     "template for driver %s\n", sht->name);
 443                 dump_stack();
 444         }
 445
 446         if (shost)
 447                 list_add_tail(&shost->sht_legacy_list, &sht->legacy_hosts);
 448         return shost;
 449 }
 450 EXPORT_SYMBOL(scsi_register);
 451
 452 void scsi_unregister(struct Scsi_Host *shost)
 453 {
 454         list_del(&shost->sht_legacy_list);
 455         scsi_host_put(shost);
 456 }
 457 EXPORT_SYMBOL(scsi_unregister);
 458
 459 static int __scsi_host_match(struct device *dev, void *data)
 460 {
 461         struct Scsi_Host *p;
 462         unsigned short *hostnum = (unsigned short *)data;
 463
 464         p = class_to_shost(dev);
 465         return p->host_no == *hostnum;
 466 }
 467
 468 /**
 469  * scsi_host_lookup - get a reference to a Scsi_Host by host no
 470  * @hostnum:    host number to locate
 471  *
 472  * Return value:
 473  *      A pointer to located Scsi_Host or NULL.
 474  *
 475  *      The caller must do a scsi_host_put() to drop the reference
 476  *      that scsi_host_get() took. The put_device() below dropped
 477  *      the reference from class_find_device().
 478  **/
 479 struct Scsi_Host *scsi_host_lookup(unsigned short hostnum)
 480 {
 481         struct device *cdev;
 482         struct Scsi_Host *shost = NULL;
 483
 484         cdev = class_find_device(&shost_class, NULL, &hostnum,
 485                                  __scsi_host_match);
 486         if (cdev) {
 487                 shost = scsi_host_get(class_to_shost(cdev));
 488                 put_device(cdev);
 489         }
 490         return shost;
 491 }
 492 EXPORT_SYMBOL(scsi_host_lookup);
 493
 494 /**
 495  * scsi_host_get - inc a Scsi_Host ref count
 496  * @shost:      Pointer to Scsi_Host to inc.
 497  **/
 498 struct Scsi_Host *scsi_host_get(struct Scsi_Host *shost)
 499 {
 500         if ((shost->shost_state == SHOST_DEL) ||
 501                 !get_device(&shost->shost_gendev))
 502                 return NULL;
 503         return shost;
 504 }
 505 EXPORT_SYMBOL(scsi_host_get);
 506
 507 /**
 508  * scsi_host_put - dec a Scsi_Host ref count
 509  * @shost:      Pointer to Scsi_Host to dec.
 510  **/
 511 void scsi_host_put(struct Scsi_Host *shost)
 512 {
 513         put_device(&shost->shost_gendev);
 514 }
 515 EXPORT_SYMBOL(scsi_host_put);
 516
 517 int scsi_init_hosts(void)
 518 {
 519         return class_register(&shost_class);
 520 }
 521
 522 void scsi_exit_hosts(void)
 523 {
 524         class_unregister(&shost_class);
 525 }
 526
 527 int scsi_is_host_device(const struct device *dev)
 528 {
 529         return dev->type == &scsi_host_type;
 530 }
 531 EXPORT_SYMBOL(scsi_is_host_device);
 532
 533 /**
 534  * scsi_queue_work - Queue work to the Scsi_Host workqueue.
 535  * @shost:      Pointer to Scsi_Host.
 536  * @work:       Work to queue for execution.
 537  *
 538  * Return value:
 539  *      1 - work queued for execution
 540  *      0 - work is already queued
 541  *      -EINVAL - work queue doesn't exist
 542  **/
 543 int scsi_queue_work(struct Scsi_Host *shost, struct work_struct *work)
 544 {
 545         if (unlikely(!shost->work_q)) {
 546                 printk(KERN_ERR
 547                         "ERROR: Scsi host '%s' attempted to queue scsi-work, "
 548                         "when no workqueue created.\n", shost->hostt->name);
 549                 dump_stack();
 550
 551                 return -EINVAL;
 552         }
 553
 554         return queue_work(shost->work_q, work);
 555 }
 556 EXPORT_SYMBOL_GPL(scsi_queue_work);
 557
 558 /**
 559  * scsi_flush_work - Flush a Scsi_Host's workqueue.
 560  * @shost:      Pointer to Scsi_Host.
 561  **/
 562 void scsi_flush_work(struct Scsi_Host *shost)
 563 {
 564         if (!shost->work_q) {
 565                 printk(KERN_ERR
 566                         "ERROR: Scsi host '%s' attempted to flush scsi-work, "
 567                         "when no workqueue created.\n", shost->hostt->name);
 568                 dump_stack();
 569                 return;
 570         }
 571
 572         flush_workqueue(shost->work_q);
 573 }
 574 EXPORT_SYMBOL_GPL(scsi_flush_work);