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