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