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         } else {
 221                 shost->bqt = blk_init_tags(shost->can_queue,
 222                                 shost->hostt->tag_alloc_policy);
 223                 if (!shost->bqt) {
 224                         error = -ENOMEM;
 225                         goto fail;
 226                 }
 227         }
 228
 229         /*
 230          * Note that we allocate the freelist even for the MQ case for now,
 231          * as we need a command set aside for scsi_reset_provider.  Having
 232          * the full host freelist and one command available for that is a
 233          * little heavy-handed, but avoids introducing a special allocator
 234          * just for this.  Eventually the structure of scsi_reset_provider
 235          * will need a major overhaul.
 236          */
 237         error = scsi_setup_command_freelist(shost);
 238         if (error)
 239                 goto out_destroy_tags;
 240
 241
 242         if (!shost->shost_gendev.parent)
 243                 shost->shost_gendev.parent = dev ? dev : &platform_bus;
 244         if (!dma_dev)
 245                 dma_dev = shost->shost_gendev.parent;
 246
 247         shost->dma_dev = dma_dev;
 248
 249         error = device_add(&shost->shost_gendev);
 250         if (error)
 251                 goto out_destroy_freelist;
 252
 253         pm_runtime_set_active(&shost->shost_gendev);
 254         pm_runtime_enable(&shost->shost_gendev);
 255         device_enable_async_suspend(&shost->shost_gendev);
 256
 257         scsi_host_set_state(shost, SHOST_RUNNING);
 258         get_device(shost->shost_gendev.parent);
 259
 260         device_enable_async_suspend(&shost->shost_dev);
 261
 262         get_device(&shost->shost_gendev);
 263         error = device_add(&shost->shost_dev);
 264         if (error)
 265                 goto out_del_gendev;
 266
 267         if (shost->transportt->host_size) {
 268                 shost->shost_data = kzalloc(shost->transportt->host_size,
 269                                          GFP_KERNEL);
 270                 if (shost->shost_data == NULL) {
 271                         error = -ENOMEM;
 272                         goto out_del_dev;
 273                 }
 274         }
 275
 276         if (shost->transportt->create_work_queue) {
 277                 snprintf(shost->work_q_name, sizeof(shost->work_q_name),
 278                          "scsi_wq_%d", shost->host_no);
 279                 shost->work_q = create_singlethread_workqueue(
 280                                         shost->work_q_name);
 281                 if (!shost->work_q) {
 282                         error = -EINVAL;
 283                         goto out_free_shost_data;
 284                 }
 285         }
 286
 287         error = scsi_sysfs_add_host(shost);
 288         if (error)
 289                 goto out_destroy_host;
 290
 291         scsi_proc_host_add(shost);
 292         return error;
 293
 294  out_destroy_host:
 295         if (shost->work_q)
 296                 destroy_workqueue(shost->work_q);
 297  out_free_shost_data:
 298         kfree(shost->shost_data);
 299  out_del_dev:
 300         device_del(&shost->shost_dev);
 301  out_del_gendev:
 302         /*
 303          * Host state is SHOST_RUNNING so we have to explicitly release
 304          * ->shost_dev.
 305          */
 306         put_device(&shost->shost_dev);
 307         device_del(&shost->shost_gendev);
 308  out_destroy_freelist:
 309         scsi_destroy_command_freelist(shost);
 310  out_destroy_tags:
 311         if (shost_use_blk_mq(shost))
 312                 scsi_mq_destroy_tags(shost);
 313  fail:
 314         return error;
 315 }
 316 EXPORT_SYMBOL(scsi_add_host_with_dma);
 317
 318 static void scsi_host_dev_release(struct device *dev)
 319 {
 320         struct Scsi_Host *shost = dev_to_shost(dev);
 321         struct device *parent = dev->parent;
 322         struct request_queue *q;
 323         void *queuedata;
 324
 325         scsi_proc_hostdir_rm(shost->hostt);
 326
 327         if (shost->tmf_work_q)
 328                 destroy_workqueue(shost->tmf_work_q);
 329         if (shost->ehandler)
 330                 kthread_stop(shost->ehandler);
 331         if (shost->work_q)
 332                 destroy_workqueue(shost->work_q);
 333         q = shost->uspace_req_q;
 334         if (q) {
 335                 queuedata = q->queuedata;
 336                 blk_cleanup_queue(q);
 337                 kfree(queuedata);
 338         }
 339
 340         if (shost->shost_state == SHOST_CREATED) {
 341                 /*
 342                  * Free the shost_dev device name here if scsi_host_alloc()
 343                  * and scsi_host_put() have been called but neither
 344                  * scsi_host_add() nor scsi_host_remove() has been called.
 345                  * This avoids that the memory allocated for the shost_dev
 346                  * name is leaked.
 347                  */
 348                 kfree(dev_name(&shost->shost_dev));
 349         }
 350
 351         scsi_destroy_command_freelist(shost);
 352         if (shost_use_blk_mq(shost)) {
 353                 if (shost->tag_set.tags)
 354                         scsi_mq_destroy_tags(shost);
 355         } else {
 356                 if (shost->bqt)
 357                         blk_free_tags(shost->bqt);
 358         }
 359
 360         kfree(shost->shost_data);
 361
 362         if (shost->shost_state != SHOST_CREATED)
 363                 put_device(parent);
 364         kfree(shost);
 365 }
 366
 367 static int shost_eh_deadline = -1;
 368
 369 module_param_named(eh_deadline, shost_eh_deadline, int, S_IRUGO|S_IWUSR);
 370 MODULE_PARM_DESC(eh_deadline,
 371                  "SCSI EH timeout in seconds (should be between 0 and 2^31-1)");
 372
 373 static struct device_type scsi_host_type = {
 374         .name =         "scsi_host",
 375         .release =      scsi_host_dev_release,
 376 };
 377
 378 /**
 379  * scsi_host_alloc - register a scsi host adapter instance.
 380  * @sht:        pointer to scsi host template
 381  * @privsize:   extra bytes to allocate for driver
 382  *
 383  * Note:
 384  *      Allocate a new Scsi_Host and perform basic initialization.
 385  *      The host is not published to the scsi midlayer until scsi_add_host
 386  *      is called.
 387  *
 388  * Return value:
 389  *      Pointer to a new Scsi_Host
 390  **/
 391 struct Scsi_Host *scsi_host_alloc(struct scsi_host_template *sht, int privsize)
 392 {
 393         struct Scsi_Host *shost;
 394         gfp_t gfp_mask = GFP_KERNEL;
 395
 396         if (sht->unchecked_isa_dma && privsize)
 397                 gfp_mask |= __GFP_DMA;
 398
 399         shost = kzalloc(sizeof(struct Scsi_Host) + privsize, gfp_mask);
 400         if (!shost)
 401                 return NULL;
 402
 403         shost->host_lock = &shost->default_lock;
 404         spin_lock_init(shost->host_lock);
 405         shost->shost_state = SHOST_CREATED;
 406         INIT_LIST_HEAD(&shost->__devices);
 407         INIT_LIST_HEAD(&shost->__targets);
 408         INIT_LIST_HEAD(&shost->eh_cmd_q);
 409         INIT_LIST_HEAD(&shost->starved_list);
 410         init_waitqueue_head(&shost->host_wait);
 411         mutex_init(&shost->scan_mutex);
 412
 413         /*
 414          * subtract one because we increment first then return, but we need to
 415          * know what the next host number was before increment
 416          */
 417         shost->host_no = atomic_inc_return(&scsi_host_next_hn) - 1;
 418         shost->dma_channel = 0xff;
 419
 420         /* These three are default values which can be overridden */
 421         shost->max_channel = 0;
 422         shost->max_id = 8;
 423         shost->max_lun = 8;
 424
 425         /* Give each shost a default transportt */
 426         shost->transportt = &blank_transport_template;
 427
 428         /*
 429          * All drivers right now should be able to handle 12 byte
 430          * commands.  Every so often there are requests for 16 byte
 431          * commands, but individual low-level drivers need to certify that
 432          * they actually do something sensible with such commands.
 433          */
 434         shost->max_cmd_len = 12;
 435         shost->hostt = sht;
 436         shost->this_id = sht->this_id;
 437         shost->can_queue = sht->can_queue;
 438         shost->sg_tablesize = sht->sg_tablesize;
 439         shost->sg_prot_tablesize = sht->sg_prot_tablesize;
 440         shost->cmd_per_lun = sht->cmd_per_lun;
 441         shost->unchecked_isa_dma = sht->unchecked_isa_dma;
 442         shost->use_clustering = sht->use_clustering;
 443         shost->no_write_same = sht->no_write_same;
 444
 445         if (shost_eh_deadline == -1 || !sht->eh_host_reset_handler)
 446                 shost->eh_deadline = -1;
 447         else if ((ulong) shost_eh_deadline * HZ > INT_MAX) {
 448                 shost_printk(KERN_WARNING, shost,
 449                              "eh_deadline %u too large, setting to %u\n",
 450                              shost_eh_deadline, INT_MAX / HZ);
 451                 shost->eh_deadline = INT_MAX;
 452         } else
 453                 shost->eh_deadline = shost_eh_deadline * HZ;
 454
 455         if (sht->supported_mode == MODE_UNKNOWN)
 456                 /* means we didn't set it ... default to INITIATOR */
 457                 shost->active_mode = MODE_INITIATOR;
 458         else
 459                 shost->active_mode = sht->supported_mode;
 460
 461         if (sht->max_host_blocked)
 462                 shost->max_host_blocked = sht->max_host_blocked;
 463         else
 464                 shost->max_host_blocked = SCSI_DEFAULT_HOST_BLOCKED;
 465
 466         /*
 467          * If the driver imposes no hard sector transfer limit, start at
 468          * machine infinity initially.
 469          */
 470         if (sht->max_sectors)
 471                 shost->max_sectors = sht->max_sectors;
 472         else
 473                 shost->max_sectors = SCSI_DEFAULT_MAX_SECTORS;
 474
 475         /*
 476          * assume a 4GB boundary, if not set
 477          */
 478         if (sht->dma_boundary)
 479                 shost->dma_boundary = sht->dma_boundary;
 480         else
 481                 shost->dma_boundary = 0xffffffff;
 482
 483         shost->use_blk_mq = scsi_use_blk_mq && !shost->hostt->disable_blk_mq;
 484
 485         device_initialize(&shost->shost_gendev);
 486         dev_set_name(&shost->shost_gendev, "host%d", shost->host_no);
 487         shost->shost_gendev.bus = &scsi_bus_type;
 488         shost->shost_gendev.type = &scsi_host_type;
 489
 490         device_initialize(&shost->shost_dev);
 491         shost->shost_dev.parent = &shost->shost_gendev;
 492         shost->shost_dev.class = &shost_class;
 493         dev_set_name(&shost->shost_dev, "host%d", shost->host_no);
 494         shost->shost_dev.groups = scsi_sysfs_shost_attr_groups;
 495
 496         shost->ehandler = kthread_run(scsi_error_handler, shost,
 497                         "scsi_eh_%d", shost->host_no);
 498         if (IS_ERR(shost->ehandler)) {
 499                 shost_printk(KERN_WARNING, shost,
 500                         "error handler thread failed to spawn, error = %ld\n",
 501                         PTR_ERR(shost->ehandler));
 502                 goto fail_kfree;
 503         }
 504
 505         shost->tmf_work_q = alloc_workqueue("scsi_tmf_%d",
 506                                             WQ_UNBOUND | WQ_MEM_RECLAIM,
 507                                            1, shost->host_no);
 508         if (!shost->tmf_work_q) {
 509                 shost_printk(KERN_WARNING, shost,
 510                              "failed to create tmf workq\n");
 511                 goto fail_kthread;
 512         }
 513         scsi_proc_hostdir_add(shost->hostt);
 514         return shost;
 515
 516  fail_kthread:
 517         kthread_stop(shost->ehandler);
 518  fail_kfree:
 519         kfree(shost);
 520         return NULL;
 521 }
 522 EXPORT_SYMBOL(scsi_host_alloc);
 523
 524 struct Scsi_Host *scsi_register(struct scsi_host_template *sht, int privsize)
 525 {
 526         struct Scsi_Host *shost = scsi_host_alloc(sht, privsize);
 527
 528         if (!sht->detect) {
 529                 printk(KERN_WARNING "scsi_register() called on new-style "
 530                                     "template for driver %s\n", sht->name);
 531                 dump_stack();
 532         }
 533
 534         if (shost)
 535                 list_add_tail(&shost->sht_legacy_list, &sht->legacy_hosts);
 536         return shost;
 537 }
 538 EXPORT_SYMBOL(scsi_register);
 539
 540 void scsi_unregister(struct Scsi_Host *shost)
 541 {
 542         list_del(&shost->sht_legacy_list);
 543         scsi_host_put(shost);
 544 }
 545 EXPORT_SYMBOL(scsi_unregister);
 546
 547 static int __scsi_host_match(struct device *dev, const void *data)
 548 {
 549         struct Scsi_Host *p;
 550         const unsigned short *hostnum = data;
 551
 552         p = class_to_shost(dev);
 553         return p->host_no == *hostnum;
 554 }
 555
 556 /**
 557  * scsi_host_lookup - get a reference to a Scsi_Host by host no
 558  * @hostnum:    host number to locate
 559  *
 560  * Return value:
 561  *      A pointer to located Scsi_Host or NULL.
 562  *
 563  *      The caller must do a scsi_host_put() to drop the reference
 564  *      that scsi_host_get() took. The put_device() below dropped
 565  *      the reference from class_find_device().
 566  **/
 567 struct Scsi_Host *scsi_host_lookup(unsigned short hostnum)
 568 {
 569         struct device *cdev;
 570         struct Scsi_Host *shost = NULL;
 571
 572         cdev = class_find_device(&shost_class, NULL, &hostnum,
 573                                  __scsi_host_match);
 574         if (cdev) {
 575                 shost = scsi_host_get(class_to_shost(cdev));
 576                 put_device(cdev);
 577         }
 578         return shost;
 579 }
 580 EXPORT_SYMBOL(scsi_host_lookup);
 581
 582 /**
 583  * scsi_host_get - inc a Scsi_Host ref count
 584  * @shost:      Pointer to Scsi_Host to inc.
 585  **/
 586 struct Scsi_Host *scsi_host_get(struct Scsi_Host *shost)
 587 {
 588         if ((shost->shost_state == SHOST_DEL) ||
 589                 !get_device(&shost->shost_gendev))
 590                 return NULL;
 591         return shost;
 592 }
 593 EXPORT_SYMBOL(scsi_host_get);
 594
 595 /**
 596  * scsi_host_put - dec a Scsi_Host ref count
 597  * @shost:      Pointer to Scsi_Host to dec.
 598  **/
 599 void scsi_host_put(struct Scsi_Host *shost)
 600 {
 601         put_device(&shost->shost_gendev);
 602 }
 603 EXPORT_SYMBOL(scsi_host_put);
 604
 605 int scsi_init_hosts(void)
 606 {
 607         return class_register(&shost_class);
 608 }
 609
 610 void scsi_exit_hosts(void)
 611 {
 612         class_unregister(&shost_class);
 613 }
 614
 615 int scsi_is_host_device(const struct device *dev)
 616 {
 617         return dev->type == &scsi_host_type;
 618 }
 619 EXPORT_SYMBOL(scsi_is_host_device);
 620
 621 /**
 622  * scsi_queue_work - Queue work to the Scsi_Host workqueue.
 623  * @shost:      Pointer to Scsi_Host.
 624  * @work:       Work to queue for execution.
 625  *
 626  * Return value:
 627  *      1 - work queued for execution
 628  *      0 - work is already queued
 629  *      -EINVAL - work queue doesn't exist
 630  **/
 631 int scsi_queue_work(struct Scsi_Host *shost, struct work_struct *work)
 632 {
 633         if (unlikely(!shost->work_q)) {
 634                 shost_printk(KERN_ERR, shost,
 635                         "ERROR: Scsi host '%s' attempted to queue scsi-work, "
 636                         "when no workqueue created.\n", shost->hostt->name);
 637                 dump_stack();
 638
 639                 return -EINVAL;
 640         }
 641
 642         return queue_work(shost->work_q, work);
 643 }
 644 EXPORT_SYMBOL_GPL(scsi_queue_work);
 645
 646 /**
 647  * scsi_flush_work - Flush a Scsi_Host's workqueue.
 648  * @shost:      Pointer to Scsi_Host.
 649  **/
 650 void scsi_flush_work(struct Scsi_Host *shost)
 651 {
 652         if (!shost->work_q) {
 653                 shost_printk(KERN_ERR, shost,
 654                         "ERROR: Scsi host '%s' attempted to flush scsi-work, "
 655                         "when no workqueue created.\n", shost->hostt->name);
 656                 dump_stack();
 657                 return;
 658         }
 659
 660         flush_workqueue(shost->work_q);
 661 }
 662 EXPORT_SYMBOL_GPL(scsi_flush_work);