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