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 #include <linux/pm_runtime.h>
  36
  37 #include <scsi/scsi_device.h>
  38 #include <scsi/scsi_host.h>
  39 #include <scsi/scsi_transport.h>
  40
  41 #include "scsi_priv.h"
  42 #include "scsi_logging.h"
  43
  44
  45 static atomic_t scsi_host_next_hn = ATOMIC_INIT(0);     /* host_no for next new host */
  46
  47
  48 static void scsi_host_cls_release(struct device *dev)
  49 {
  50         put_device(&class_to_shost(dev)->shost_gendev);
  51 }
  52
  53 static struct class shost_class = {
  54         .name           = "scsi_host",
  55         .dev_release    = scsi_host_cls_release,
  56 };
  57
  58 /**
  59  *      scsi_host_set_state - Take the given host through the host state model.
  60  *      @shost: scsi host to change the state of.
  61  *      @state: state to change to.
  62  *
  63  *      Returns zero if unsuccessful or an error if the requested
  64  *      transition is illegal.
  65  **/
  66 int scsi_host_set_state(struct Scsi_Host *shost, enum scsi_host_state state)
  67 {
  68         enum scsi_host_state oldstate = shost->shost_state;
  69
  70         if (state == oldstate)
  71                 return 0;
  72
  73         switch (state) {
  74         case SHOST_CREATED:
  75                 /* There are no legal states that come back to
  76                  * created.  This is the manually initialised start
  77                  * state */
  78                 goto illegal;
  79
  80         case SHOST_RUNNING:
  81                 switch (oldstate) {
  82                 case SHOST_CREATED:
  83                 case SHOST_RECOVERY:
  84                         break;
  85                 default:
  86                         goto illegal;
  87                 }
  88                 break;
  89
  90         case SHOST_RECOVERY:
  91                 switch (oldstate) {
  92                 case SHOST_RUNNING:
  93                         break;
  94                 default:
  95                         goto illegal;
  96                 }
  97                 break;
  98
  99         case SHOST_CANCEL:
 100                 switch (oldstate) {
 101                 case SHOST_CREATED:
 102                 case SHOST_RUNNING:
 103                 case SHOST_CANCEL_RECOVERY:
 104                         break;
 105                 default:
 106                         goto illegal;
 107                 }
 108                 break;
 109
 110         case SHOST_DEL:
 111                 switch (oldstate) {
 112                 case SHOST_CANCEL:
 113                 case SHOST_DEL_RECOVERY:
 114                         break;
 115                 default:
 116                         goto illegal;
 117                 }
 118                 break;
 119
 120         case SHOST_CANCEL_RECOVERY:
 121                 switch (oldstate) {
 122                 case SHOST_CANCEL:
 123                 case SHOST_RECOVERY:
 124                         break;
 125                 default:
 126                         goto illegal;
 127                 }
 128                 break;
 129
 130         case SHOST_DEL_RECOVERY:
 131                 switch (oldstate) {
 132                 case SHOST_CANCEL_RECOVERY:
 133                         break;
 134                 default:
 135                         goto illegal;
 136                 }
 137                 break;
 138         }
 139         shost->shost_state = state;
 140         return 0;
 141
 142  illegal:
 143         SCSI_LOG_ERROR_RECOVERY(1,
 144                                 shost_printk(KERN_ERR, shost,
 145                                              "Illegal host state transition"
 146                                              "%s->%s\n",
 147                                              scsi_host_state_name(oldstate),
 148                                              scsi_host_state_name(state)));
 149         return -EINVAL;
 150 }
 151 EXPORT_SYMBOL(scsi_host_set_state);
 152
 153 /**
 154  * scsi_remove_host - remove a scsi host
 155  * @shost:      a pointer to a scsi host to remove
 156  **/
 157 void scsi_remove_host(struct Scsi_Host *shost)
 158 {
 159         unsigned long flags;
 160
 161         mutex_lock(&shost->scan_mutex);
 162         spin_lock_irqsave(shost->host_lock, flags);
 163         if (scsi_host_set_state(shost, SHOST_CANCEL))
 164                 if (scsi_host_set_state(shost, SHOST_CANCEL_RECOVERY)) {
 165                         spin_unlock_irqrestore(shost->host_lock, flags);
 166                         mutex_unlock(&shost->scan_mutex);
 167                         return;
 168                 }
 169         spin_unlock_irqrestore(shost->host_lock, flags);
 170
 171         scsi_autopm_get_host(shost);
 172         flush_workqueue(shost->tmf_work_q);
 173         scsi_forget_host(shost);
 174         mutex_unlock(&shost->scan_mutex);
 175         scsi_proc_host_rm(shost);
 176
 177         spin_lock_irqsave(shost->host_lock, flags);
 178         if (scsi_host_set_state(shost, SHOST_DEL))
 179                 BUG_ON(scsi_host_set_state(shost, SHOST_DEL_RECOVERY));
 180         spin_unlock_irqrestore(shost->host_lock, flags);
 181
 182         transport_unregister_device(&shost->shost_gendev);
 183         device_unregister(&shost->shost_dev);
 184         device_del(&shost->shost_gendev);
 185 }
 186 EXPORT_SYMBOL(scsi_remove_host);
 187
 188 /**
 189  * scsi_add_host_with_dma - add a scsi host with dma device
 190  * @shost:      scsi host pointer to add
 191  * @dev:        a struct device of type scsi class
 192  * @dma_dev:    dma device for the host
 193  *
 194  * Note: You rarely need to worry about this unless you're in a
 195  * virtualised host environments, so use the simpler scsi_add_host()
 196  * function instead.
 197  *
 198  * Return value:
 199  *      0 on success / != 0 for error
 200  **/
 201 int scsi_add_host_with_dma(struct Scsi_Host *shost, struct device *dev,
 202                            struct device *dma_dev)
 203 {
 204         struct scsi_host_template *sht = shost->hostt;
 205         int error = -EINVAL;
 206
 207         shost_printk(KERN_INFO, shost, "%s\n",
 208                         sht->info ? sht->info(shost) : sht->name);
 209
 210         if (!shost->can_queue) {
 211                 shost_printk(KERN_ERR, shost,
 212                              "can_queue = 0 no longer supported\n");
 213                 goto fail;
 214         }
 215
 216         if (shost_use_blk_mq(shost)) {
 217                 error = scsi_mq_setup_tags(shost);
 218                 if (error)
 219                         goto fail;
 220         }
 221
 222         /*
 223          * Note that we allocate the freelist even for the MQ case for now,
 224          * as we need a command set aside for scsi_reset_provider.  Having
 225          * the full host freelist and one command available for that is a
 226          * little heavy-handed, but avoids introducing a special allocator
 227          * just for this.  Eventually the structure of scsi_reset_provider
 228          * will need a major overhaul.
 229          */
 230         error = scsi_setup_command_freelist(shost);
 231         if (error)
 232                 goto out_destroy_tags;
 233
 234
 235         if (!shost->shost_gendev.parent)
 236                 shost->shost_gendev.parent = dev ? dev : &platform_bus;
 237         if (!dma_dev)
 238                 dma_dev = shost->shost_gendev.parent;
 239
 240         shost->dma_dev = dma_dev;
 241
 242         error = device_add(&shost->shost_gendev);
 243         if (error)
 244                 goto out_destroy_freelist;
 245
 246         pm_runtime_set_active(&shost->shost_gendev);
 247         pm_runtime_enable(&shost->shost_gendev);
 248         device_enable_async_suspend(&shost->shost_gendev);
 249
 250         scsi_host_set_state(shost, SHOST_RUNNING);
 251         get_device(shost->shost_gendev.parent);
 252
 253         device_enable_async_suspend(&shost->shost_dev);
 254
 255         error = device_add(&shost->shost_dev);
 256         if (error)
 257                 goto out_del_gendev;
 258
 259         get_device(&shost->shost_gendev);
 260
 261         if (shost->transportt->host_size) {
 262                 shost->shost_data = kzalloc(shost->transportt->host_size,
 263                                          GFP_KERNEL);
 264                 if (shost->shost_data == NULL) {
 265                         error = -ENOMEM;
 266                         goto out_del_dev;
 267                 }
 268         }
 269
 270         if (shost->transportt->create_work_queue) {
 271                 snprintf(shost->work_q_name, sizeof(shost->work_q_name),
 272                          "scsi_wq_%d", shost->host_no);
 273                 shost->work_q = create_singlethread_workqueue(
 274                                         shost->work_q_name);
 275                 if (!shost->work_q) {
 276                         error = -EINVAL;
 277                         goto out_free_shost_data;
 278                 }
 279         }
 280
 281         error = scsi_sysfs_add_host(shost);
 282         if (error)
 283                 goto out_destroy_host;
 284
 285         scsi_proc_host_add(shost);
 286         return error;
 287
 288  out_destroy_host:
 289         if (shost->work_q)
 290                 destroy_workqueue(shost->work_q);
 291  out_free_shost_data:
 292         kfree(shost->shost_data);
 293  out_del_dev:
 294         device_del(&shost->shost_dev);
 295  out_del_gendev:
 296         device_del(&shost->shost_gendev);
 297  out_destroy_freelist:
 298         scsi_destroy_command_freelist(shost);
 299  out_destroy_tags:
 300         if (shost_use_blk_mq(shost))
 301                 scsi_mq_destroy_tags(shost);
 302  fail:
 303         return error;
 304 }
 305 EXPORT_SYMBOL(scsi_add_host_with_dma);
 306
 307 static void scsi_host_dev_release(struct device *dev)
 308 {
 309         struct Scsi_Host *shost = dev_to_shost(dev);
 310         struct device *parent = dev->parent;
 311         struct request_queue *q;
 312         void *queuedata;
 313
 314         scsi_proc_hostdir_rm(shost->hostt);
 315
 316         if (shost->tmf_work_q)
 317                 destroy_workqueue(shost->tmf_work_q);
 318         if (shost->ehandler)
 319                 kthread_stop(shost->ehandler);
 320         if (shost->work_q)
 321                 destroy_workqueue(shost->work_q);
 322         q = shost->uspace_req_q;
 323         if (q) {
 324                 queuedata = q->queuedata;
 325                 blk_cleanup_queue(q);
 326                 kfree(queuedata);
 327         }
 328
 329         scsi_destroy_command_freelist(shost);
 330         if (shost_use_blk_mq(shost)) {
 331                 if (shost->tag_set.tags)
 332                         scsi_mq_destroy_tags(shost);
 333         } else {
 334                 if (shost->bqt)
 335                         blk_free_tags(shost->bqt);
 336         }
 337
 338         kfree(shost->shost_data);
 339
 340         if (parent)
 341                 put_device(parent);
 342         kfree(shost);
 343 }
 344
 345 static int shost_eh_deadline = -1;
 346
 347 module_param_named(eh_deadline, shost_eh_deadline, int, S_IRUGO|S_IWUSR);
 348 MODULE_PARM_DESC(eh_deadline,
 349                  "SCSI EH timeout in seconds (should be between 0 and 2^31-1)");
 350
 351 static struct device_type scsi_host_type = {
 352         .name =         "scsi_host",
 353         .release =      scsi_host_dev_release,
 354 };
 355
 356 /**
 357  * scsi_host_alloc - register a scsi host adapter instance.
 358  * @sht:        pointer to scsi host template
 359  * @privsize:   extra bytes to allocate for driver
 360  *
 361  * Note:
 362  *      Allocate a new Scsi_Host and perform basic initialization.
 363  *      The host is not published to the scsi midlayer until scsi_add_host
 364  *      is called.
 365  *
 366  * Return value:
 367  *      Pointer to a new Scsi_Host
 368  **/
 369 struct Scsi_Host *scsi_host_alloc(struct scsi_host_template *sht, int privsize)
 370 {
 371         struct Scsi_Host *shost;
 372         gfp_t gfp_mask = GFP_KERNEL;
 373
 374         if (sht->unchecked_isa_dma && privsize)
 375                 gfp_mask |= __GFP_DMA;
 376
 377         shost = kzalloc(sizeof(struct Scsi_Host) + privsize, gfp_mask);
 378         if (!shost)
 379                 return NULL;
 380
 381         shost->host_lock = &shost->default_lock;
 382         spin_lock_init(shost->host_lock);
 383         shost->shost_state = SHOST_CREATED;
 384         INIT_LIST_HEAD(&shost->__devices);
 385         INIT_LIST_HEAD(&shost->__targets);
 386         INIT_LIST_HEAD(&shost->eh_cmd_q);
 387         INIT_LIST_HEAD(&shost->starved_list);
 388         init_waitqueue_head(&shost->host_wait);
 389         mutex_init(&shost->scan_mutex);
 390
 391         /*
 392          * subtract one because we increment first then return, but we need to
 393          * know what the next host number was before increment
 394          */
 395         shost->host_no = atomic_inc_return(&scsi_host_next_hn) - 1;
 396         shost->dma_channel = 0xff;
 397
 398         /* These three are default values which can be overridden */
 399         shost->max_channel = 0;
 400         shost->max_id = 8;
 401         shost->max_lun = 8;
 402
 403         /* Give each shost a default transportt */
 404         shost->transportt = &blank_transport_template;
 405
 406         /*
 407          * All drivers right now should be able to handle 12 byte
 408          * commands.  Every so often there are requests for 16 byte
 409          * commands, but individual low-level drivers need to certify that
 410          * they actually do something sensible with such commands.
 411          */
 412         shost->max_cmd_len = 12;
 413         shost->hostt = sht;
 414         shost->this_id = sht->this_id;
 415         shost->can_queue = sht->can_queue;
 416         shost->sg_tablesize = sht->sg_tablesize;
 417         shost->sg_prot_tablesize = sht->sg_prot_tablesize;
 418         shost->cmd_per_lun = sht->cmd_per_lun;
 419         shost->unchecked_isa_dma = sht->unchecked_isa_dma;
 420         shost->use_clustering = sht->use_clustering;
 421         shost->ordered_tag = sht->ordered_tag;
 422         shost->no_write_same = sht->no_write_same;
 423
 424         if (shost_eh_deadline == -1 || !sht->eh_host_reset_handler)
 425                 shost->eh_deadline = -1;
 426         else if ((ulong) shost_eh_deadline * HZ > INT_MAX) {
 427                 shost_printk(KERN_WARNING, shost,
 428                              "eh_deadline %u too large, setting to %u\n",
 429                              shost_eh_deadline, INT_MAX / HZ);
 430                 shost->eh_deadline = INT_MAX;
 431         } else
 432                 shost->eh_deadline = shost_eh_deadline * HZ;
 433
 434         if (sht->supported_mode == MODE_UNKNOWN)
 435                 /* means we didn't set it ... default to INITIATOR */
 436                 shost->active_mode = MODE_INITIATOR;
 437         else
 438                 shost->active_mode = sht->supported_mode;
 439
 440         if (sht->max_host_blocked)
 441                 shost->max_host_blocked = sht->max_host_blocked;
 442         else
 443                 shost->max_host_blocked = SCSI_DEFAULT_HOST_BLOCKED;
 444
 445         /*
 446          * If the driver imposes no hard sector transfer limit, start at
 447          * machine infinity initially.
 448          */
 449         if (sht->max_sectors)
 450                 shost->max_sectors = sht->max_sectors;
 451         else
 452                 shost->max_sectors = SCSI_DEFAULT_MAX_SECTORS;
 453
 454         /*
 455          * assume a 4GB boundary, if not set
 456          */
 457         if (sht->dma_boundary)
 458                 shost->dma_boundary = sht->dma_boundary;
 459         else
 460                 shost->dma_boundary = 0xffffffff;
 461
 462         shost->use_blk_mq = scsi_use_blk_mq && !shost->hostt->disable_blk_mq;
 463
 464         device_initialize(&shost->shost_gendev);
 465         dev_set_name(&shost->shost_gendev, "host%d", shost->host_no);
 466         shost->shost_gendev.bus = &scsi_bus_type;
 467         shost->shost_gendev.type = &scsi_host_type;
 468
 469         device_initialize(&shost->shost_dev);
 470         shost->shost_dev.parent = &shost->shost_gendev;
 471         shost->shost_dev.class = &shost_class;
 472         dev_set_name(&shost->shost_dev, "host%d", shost->host_no);
 473         shost->shost_dev.groups = scsi_sysfs_shost_attr_groups;
 474
 475         shost->ehandler = kthread_run(scsi_error_handler, shost,
 476                         "scsi_eh_%d", shost->host_no);
 477         if (IS_ERR(shost->ehandler)) {
 478                 shost_printk(KERN_WARNING, shost,
 479                         "error handler thread failed to spawn, error = %ld\n",
 480                         PTR_ERR(shost->ehandler));
 481                 goto fail_kfree;
 482         }
 483
 484         shost->tmf_work_q = alloc_workqueue("scsi_tmf_%d",
 485                                             WQ_UNBOUND | WQ_MEM_RECLAIM,
 486                                            1, shost->host_no);
 487         if (!shost->tmf_work_q) {
 488                 printk(KERN_WARNING "scsi%d: failed to create tmf workq\n",
 489                        shost->host_no);
 490                 goto fail_kthread;
 491         }
 492         scsi_proc_hostdir_add(shost->hostt);
 493         return shost;
 494
 495  fail_kthread:
 496         kthread_stop(shost->ehandler);
 497  fail_kfree:
 498         kfree(shost);
 499         return NULL;
 500 }
 501 EXPORT_SYMBOL(scsi_host_alloc);
 502
 503 struct Scsi_Host *scsi_register(struct scsi_host_template *sht, int privsize)
 504 {
 505         struct Scsi_Host *shost = scsi_host_alloc(sht, privsize);
 506
 507         if (!sht->detect) {
 508                 printk(KERN_WARNING "scsi_register() called on new-style "
 509                                     "template for driver %s\n", sht->name);
 510                 dump_stack();
 511         }
 512
 513         if (shost)
 514                 list_add_tail(&shost->sht_legacy_list, &sht->legacy_hosts);
 515         return shost;
 516 }
 517 EXPORT_SYMBOL(scsi_register);
 518
 519 void scsi_unregister(struct Scsi_Host *shost)
 520 {
 521         list_del(&shost->sht_legacy_list);
 522         scsi_host_put(shost);
 523 }
 524 EXPORT_SYMBOL(scsi_unregister);
 525
 526 static int __scsi_host_match(struct device *dev, const void *data)
 527 {
 528         struct Scsi_Host *p;
 529         const unsigned short *hostnum = data;
 530
 531         p = class_to_shost(dev);
 532         return p->host_no == *hostnum;
 533 }
 534
 535 /**
 536  * scsi_host_lookup - get a reference to a Scsi_Host by host no
 537  * @hostnum:    host number to locate
 538  *
 539  * Return value:
 540  *      A pointer to located Scsi_Host or NULL.
 541  *
 542  *      The caller must do a scsi_host_put() to drop the reference
 543  *      that scsi_host_get() took. The put_device() below dropped
 544  *      the reference from class_find_device().
 545  **/
 546 struct Scsi_Host *scsi_host_lookup(unsigned short hostnum)
 547 {
 548         struct device *cdev;
 549         struct Scsi_Host *shost = NULL;
 550
 551         cdev = class_find_device(&shost_class, NULL, &hostnum,
 552                                  __scsi_host_match);
 553         if (cdev) {
 554                 shost = scsi_host_get(class_to_shost(cdev));
 555                 put_device(cdev);
 556         }
 557         return shost;
 558 }
 559 EXPORT_SYMBOL(scsi_host_lookup);
 560
 561 /**
 562  * scsi_host_get - inc a Scsi_Host ref count
 563  * @shost:      Pointer to Scsi_Host to inc.
 564  **/
 565 struct Scsi_Host *scsi_host_get(struct Scsi_Host *shost)
 566 {
 567         if ((shost->shost_state == SHOST_DEL) ||
 568                 !get_device(&shost->shost_gendev))
 569                 return NULL;
 570         return shost;
 571 }
 572 EXPORT_SYMBOL(scsi_host_get);
 573
 574 /**
 575  * scsi_host_put - dec a Scsi_Host ref count
 576  * @shost:      Pointer to Scsi_Host to dec.
 577  **/
 578 void scsi_host_put(struct Scsi_Host *shost)
 579 {
 580         put_device(&shost->shost_gendev);
 581 }
 582 EXPORT_SYMBOL(scsi_host_put);
 583
 584 int scsi_init_hosts(void)
 585 {
 586         return class_register(&shost_class);
 587 }
 588
 589 void scsi_exit_hosts(void)
 590 {
 591         class_unregister(&shost_class);
 592 }
 593
 594 int scsi_is_host_device(const struct device *dev)
 595 {
 596         return dev->type == &scsi_host_type;
 597 }
 598 EXPORT_SYMBOL(scsi_is_host_device);
 599
 600 /**
 601  * scsi_queue_work - Queue work to the Scsi_Host workqueue.
 602  * @shost:      Pointer to Scsi_Host.
 603  * @work:       Work to queue for execution.
 604  *
 605  * Return value:
 606  *      1 - work queued for execution
 607  *      0 - work is already queued
 608  *      -EINVAL - work queue doesn't exist
 609  **/
 610 int scsi_queue_work(struct Scsi_Host *shost, struct work_struct *work)
 611 {
 612         if (unlikely(!shost->work_q)) {
 613                 shost_printk(KERN_ERR, shost,
 614                         "ERROR: Scsi host '%s' attempted to queue scsi-work, "
 615                         "when no workqueue created.\n", shost->hostt->name);
 616                 dump_stack();
 617
 618                 return -EINVAL;
 619         }
 620
 621         return queue_work(shost->work_q, work);
 622 }
 623 EXPORT_SYMBOL_GPL(scsi_queue_work);
 624
 625 /**
 626  * scsi_flush_work - Flush a Scsi_Host's workqueue.
 627  * @shost:      Pointer to Scsi_Host.
 628  **/
 629 void scsi_flush_work(struct Scsi_Host *shost)
 630 {
 631         if (!shost->work_q) {
 632                 shost_printk(KERN_ERR, shost,
 633                         "ERROR: Scsi host '%s' attempted to flush scsi-work, "
 634                         "when no workqueue created.\n", shost->hostt->name);
 635                 dump_stack();
 636                 return;
 637         }
 638
 639         flush_workqueue(shost->work_q);
 640 }
 641 EXPORT_SYMBOL_GPL(scsi_flush_work);