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