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 #include <linux/idr.h>
  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 int shost_eh_deadline = -1;
  46
  47 module_param_named(eh_deadline, shost_eh_deadline, int, S_IRUGO|S_IWUSR);
  48 MODULE_PARM_DESC(eh_deadline,
  49                  "SCSI EH timeout in seconds (should be between 0 and 2^31-1)");
  50
  51 static DEFINE_IDA(host_index_ida);
  52
  53
  54 static void scsi_host_cls_release(struct device *dev)
  55 {
  56         put_device(&class_to_shost(dev)->shost_gendev);
  57 }
  58
  59 static struct class shost_class = {
  60         .name           = "scsi_host",
  61         .dev_release    = scsi_host_cls_release,
  62 };
  63
  64 /**
  65  *      scsi_host_set_state - Take the given host through the host state model.
  66  *      @shost: scsi host to change the state of.
  67  *      @state: state to change to.
  68  *
  69  *      Returns zero if unsuccessful or an error if the requested
  70  *      transition is illegal.
  71  **/
  72 int scsi_host_set_state(struct Scsi_Host *shost, enum scsi_host_state state)
  73 {
  74         enum scsi_host_state oldstate = shost->shost_state;
  75
  76         if (state == oldstate)
  77                 return 0;
  78
  79         switch (state) {
  80         case SHOST_CREATED:
  81                 /* There are no legal states that come back to
  82                  * created.  This is the manually initialised start
  83                  * state */
  84                 goto illegal;
  85
  86         case SHOST_RUNNING:
  87                 switch (oldstate) {
  88                 case SHOST_CREATED:
  89                 case SHOST_RECOVERY:
  90                         break;
  91                 default:
  92                         goto illegal;
  93                 }
  94                 break;
  95
  96         case SHOST_RECOVERY:
  97                 switch (oldstate) {
  98                 case SHOST_RUNNING:
  99                         break;
 100                 default:
 101                         goto illegal;
 102                 }
 103                 break;
 104
 105         case SHOST_CANCEL:
 106                 switch (oldstate) {
 107                 case SHOST_CREATED:
 108                 case SHOST_RUNNING:
 109                 case SHOST_CANCEL_RECOVERY:
 110                         break;
 111                 default:
 112                         goto illegal;
 113                 }
 114                 break;
 115
 116         case SHOST_DEL:
 117                 switch (oldstate) {
 118                 case SHOST_CANCEL:
 119                 case SHOST_DEL_RECOVERY:
 120                         break;
 121                 default:
 122                         goto illegal;
 123                 }
 124                 break;
 125
 126         case SHOST_CANCEL_RECOVERY:
 127                 switch (oldstate) {
 128                 case SHOST_CANCEL:
 129                 case SHOST_RECOVERY:
 130                         break;
 131                 default:
 132                         goto illegal;
 133                 }
 134                 break;
 135
 136         case SHOST_DEL_RECOVERY:
 137                 switch (oldstate) {
 138                 case SHOST_CANCEL_RECOVERY:
 139                         break;
 140                 default:
 141                         goto illegal;
 142                 }
 143                 break;
 144         }
 145         shost->shost_state = state;
 146         return 0;
 147
 148  illegal:
 149         SCSI_LOG_ERROR_RECOVERY(1,
 150                                 shost_printk(KERN_ERR, shost,
 151                                              "Illegal host state transition"
 152                                              "%s->%s\n",
 153                                              scsi_host_state_name(oldstate),
 154                                              scsi_host_state_name(state)));
 155         return -EINVAL;
 156 }
 157
 158 /**
 159  * scsi_remove_host - remove a scsi host
 160  * @shost:      a pointer to a scsi host to remove
 161  **/
 162 void scsi_remove_host(struct Scsi_Host *shost)
 163 {
 164         unsigned long flags;
 165
 166         mutex_lock(&shost->scan_mutex);
 167         spin_lock_irqsave(shost->host_lock, flags);
 168         if (scsi_host_set_state(shost, SHOST_CANCEL))
 169                 if (scsi_host_set_state(shost, SHOST_CANCEL_RECOVERY)) {
 170                         spin_unlock_irqrestore(shost->host_lock, flags);
 171                         mutex_unlock(&shost->scan_mutex);
 172                         return;
 173                 }
 174         spin_unlock_irqrestore(shost->host_lock, flags);
 175
 176         scsi_autopm_get_host(shost);
 177         flush_workqueue(shost->tmf_work_q);
 178         scsi_forget_host(shost);
 179         mutex_unlock(&shost->scan_mutex);
 180         scsi_proc_host_rm(shost);
 181
 182         spin_lock_irqsave(shost->host_lock, flags);
 183         if (scsi_host_set_state(shost, SHOST_DEL))
 184                 BUG_ON(scsi_host_set_state(shost, SHOST_DEL_RECOVERY));
 185         spin_unlock_irqrestore(shost->host_lock, flags);
 186
 187         transport_unregister_device(&shost->shost_gendev);
 188         device_unregister(&shost->shost_dev);
 189         device_del(&shost->shost_gendev);
 190 }
 191 EXPORT_SYMBOL(scsi_remove_host);
 192
 193 /**
 194  * scsi_add_host_with_dma - add a scsi host with dma device
 195  * @shost:      scsi host pointer to add
 196  * @dev:        a struct device of type scsi class
 197  * @dma_dev:    dma device for the host
 198  *
 199  * Note: You rarely need to worry about this unless you're in a
 200  * virtualised host environments, so use the simpler scsi_add_host()
 201  * function instead.
 202  *
 203  * Return value:
 204  *      0 on success / != 0 for error
 205  **/
 206 int scsi_add_host_with_dma(struct Scsi_Host *shost, struct device *dev,
 207                            struct device *dma_dev)
 208 {
 209         struct scsi_host_template *sht = shost->hostt;
 210         int error = -EINVAL;
 211
 212         shost_printk(KERN_INFO, shost, "%s\n",
 213                         sht->info ? sht->info(shost) : sht->name);
 214
 215         if (!shost->can_queue) {
 216                 shost_printk(KERN_ERR, shost,
 217                              "can_queue = 0 no longer supported\n");
 218                 goto fail;
 219         }
 220
 221         error = scsi_init_sense_cache(shost);
 222         if (error)
 223                 goto fail;
 224
 225         if (shost_use_blk_mq(shost)) {
 226                 error = scsi_mq_setup_tags(shost);
 227                 if (error)
 228                         goto fail;
 229         } else {
 230                 shost->bqt = blk_init_tags(shost->can_queue,
 231                                 shost->hostt->tag_alloc_policy);
 232                 if (!shost->bqt) {
 233                         error = -ENOMEM;
 234                         goto fail;
 235                 }
 236         }
 237
 238         if (!shost->shost_gendev.parent)
 239                 shost->shost_gendev.parent = dev ? dev : &platform_bus;
 240         if (!dma_dev)
 241                 dma_dev = shost->shost_gendev.parent;
 242
 243         shost->dma_dev = dma_dev;
 244
 245         /*
 246          * Increase usage count temporarily here so that calling
 247          * scsi_autopm_put_host() will trigger runtime idle if there is
 248          * nothing else preventing suspending the device.
 249          */
 250         pm_runtime_get_noresume(&shost->shost_gendev);
 251         pm_runtime_set_active(&shost->shost_gendev);
 252         pm_runtime_enable(&shost->shost_gendev);
 253         device_enable_async_suspend(&shost->shost_gendev);
 254
 255         error = device_add(&shost->shost_gendev);
 256         if (error)
 257                 goto out_disable_runtime_pm;
 258
 259         scsi_host_set_state(shost, SHOST_RUNNING);
 260         get_device(shost->shost_gendev.parent);
 261
 262         device_enable_async_suspend(&shost->shost_dev);
 263
 264         error = device_add(&shost->shost_dev);
 265         if (error)
 266                 goto out_del_gendev;
 267
 268         get_device(&shost->shost_gendev);
 269
 270         if (shost->transportt->host_size) {
 271                 shost->shost_data = kzalloc(shost->transportt->host_size,
 272                                          GFP_KERNEL);
 273                 if (shost->shost_data == NULL) {
 274                         error = -ENOMEM;
 275                         goto out_del_dev;
 276                 }
 277         }
 278
 279         if (shost->transportt->create_work_queue) {
 280                 snprintf(shost->work_q_name, sizeof(shost->work_q_name),
 281                          "scsi_wq_%d", shost->host_no);
 282                 shost->work_q = create_singlethread_workqueue(
 283                                         shost->work_q_name);
 284                 if (!shost->work_q) {
 285                         error = -EINVAL;
 286                         goto out_free_shost_data;
 287                 }
 288         }
 289
 290         error = scsi_sysfs_add_host(shost);
 291         if (error)
 292                 goto out_destroy_host;
 293
 294         scsi_proc_host_add(shost);
 295         scsi_autopm_put_host(shost);
 296         return error;
 297
 298  out_destroy_host:
 299         if (shost->work_q)
 300                 destroy_workqueue(shost->work_q);
 301  out_free_shost_data:
 302         kfree(shost->shost_data);
 303  out_del_dev:
 304         device_del(&shost->shost_dev);
 305  out_del_gendev:
 306         device_del(&shost->shost_gendev);
 307  out_disable_runtime_pm:
 308         device_disable_async_suspend(&shost->shost_gendev);
 309         pm_runtime_disable(&shost->shost_gendev);
 310         pm_runtime_set_suspended(&shost->shost_gendev);
 311         pm_runtime_put_noidle(&shost->shost_gendev);
 312         if (shost_use_blk_mq(shost))
 313                 scsi_mq_destroy_tags(shost);
 314  fail:
 315         return error;
 316 }
 317 EXPORT_SYMBOL(scsi_add_host_with_dma);
 318
 319 static void scsi_host_dev_release(struct device *dev)
 320 {
 321         struct Scsi_Host *shost = dev_to_shost(dev);
 322         struct device *parent = dev->parent;
 323
 324         scsi_proc_hostdir_rm(shost->hostt);
 325
 326         /* Wait for functions invoked through call_rcu(&shost->rcu, ...) */
 327         rcu_barrier();
 328
 329         if (shost->tmf_work_q)
 330                 destroy_workqueue(shost->tmf_work_q);
 331         if (shost->ehandler)
 332                 kthread_stop(shost->ehandler);
 333         if (shost->work_q)
 334                 destroy_workqueue(shost->work_q);
 335
 336         if (shost->shost_state == SHOST_CREATED) {
 337                 /*
 338                  * Free the shost_dev device name here if scsi_host_alloc()
 339                  * and scsi_host_put() have been called but neither
 340                  * scsi_host_add() nor scsi_host_remove() has been called.
 341                  * This avoids that the memory allocated for the shost_dev
 342                  * name is leaked.
 343                  */
 344                 kfree(dev_name(&shost->shost_dev));
 345         }
 346
 347         if (shost_use_blk_mq(shost)) {
 348                 if (shost->tag_set.tags)
 349                         scsi_mq_destroy_tags(shost);
 350         } else {
 351                 if (shost->bqt)
 352                         blk_free_tags(shost->bqt);
 353         }
 354
 355         kfree(shost->shost_data);
 356
 357         ida_simple_remove(&host_index_ida, shost->host_no);
 358
 359         if (parent)
 360                 put_device(parent);
 361         kfree(shost);
 362 }
 363
 364 static struct device_type scsi_host_type = {
 365         .name =         "scsi_host",
 366         .release =      scsi_host_dev_release,
 367 };
 368
 369 /**
 370  * scsi_host_alloc - register a scsi host adapter instance.
 371  * @sht:        pointer to scsi host template
 372  * @privsize:   extra bytes to allocate for driver
 373  *
 374  * Note:
 375  *      Allocate a new Scsi_Host and perform basic initialization.
 376  *      The host is not published to the scsi midlayer until scsi_add_host
 377  *      is called.
 378  *
 379  * Return value:
 380  *      Pointer to a new Scsi_Host
 381  **/
 382 struct Scsi_Host *scsi_host_alloc(struct scsi_host_template *sht, int privsize)
 383 {
 384         struct Scsi_Host *shost;
 385         gfp_t gfp_mask = GFP_KERNEL;
 386         int index;
 387
 388         if (sht->unchecked_isa_dma && privsize)
 389                 gfp_mask |= __GFP_DMA;
 390
 391         shost = kzalloc(sizeof(struct Scsi_Host) + privsize, gfp_mask);
 392         if (!shost)
 393                 return NULL;
 394
 395         shost->host_lock = &shost->default_lock;
 396         spin_lock_init(shost->host_lock);
 397         shost->shost_state = SHOST_CREATED;
 398         INIT_LIST_HEAD(&shost->__devices);
 399         INIT_LIST_HEAD(&shost->__targets);
 400         INIT_LIST_HEAD(&shost->eh_cmd_q);
 401         INIT_LIST_HEAD(&shost->starved_list);
 402         init_waitqueue_head(&shost->host_wait);
 403         mutex_init(&shost->scan_mutex);
 404
 405         index = ida_simple_get(&host_index_ida, 0, 0, GFP_KERNEL);
 406         if (index < 0)
 407                 goto fail_kfree;
 408         shost->host_no = index;
 409
 410         shost->dma_channel = 0xff;
 411
 412         /* These three are default values which can be overridden */
 413         shost->max_channel = 0;
 414         shost->max_id = 8;
 415         shost->max_lun = 8;
 416
 417         /* Give each shost a default transportt */
 418         shost->transportt = &blank_transport_template;
 419
 420         /*
 421          * All drivers right now should be able to handle 12 byte
 422          * commands.  Every so often there are requests for 16 byte
 423          * commands, but individual low-level drivers need to certify that
 424          * they actually do something sensible with such commands.
 425          */
 426         shost->max_cmd_len = 12;
 427         shost->hostt = sht;
 428         shost->this_id = sht->this_id;
 429         shost->can_queue = sht->can_queue;
 430         shost->sg_tablesize = sht->sg_tablesize;
 431         shost->sg_prot_tablesize = sht->sg_prot_tablesize;
 432         shost->cmd_per_lun = sht->cmd_per_lun;
 433         shost->unchecked_isa_dma = sht->unchecked_isa_dma;
 434         shost->use_clustering = sht->use_clustering;
 435         shost->no_write_same = sht->no_write_same;
 436
 437         if (shost_eh_deadline == -1 || !sht->eh_host_reset_handler)
 438                 shost->eh_deadline = -1;
 439         else if ((ulong) shost_eh_deadline * HZ > INT_MAX) {
 440                 shost_printk(KERN_WARNING, shost,
 441                              "eh_deadline %u too large, setting to %u\n",
 442                              shost_eh_deadline, INT_MAX / HZ);
 443                 shost->eh_deadline = INT_MAX;
 444         } else
 445                 shost->eh_deadline = shost_eh_deadline * HZ;
 446
 447         if (sht->supported_mode == MODE_UNKNOWN)
 448                 /* means we didn't set it ... default to INITIATOR */
 449                 shost->active_mode = MODE_INITIATOR;
 450         else
 451                 shost->active_mode = sht->supported_mode;
 452
 453         if (sht->max_host_blocked)
 454                 shost->max_host_blocked = sht->max_host_blocked;
 455         else
 456                 shost->max_host_blocked = SCSI_DEFAULT_HOST_BLOCKED;
 457
 458         /*
 459          * If the driver imposes no hard sector transfer limit, start at
 460          * machine infinity initially.
 461          */
 462         if (sht->max_sectors)
 463                 shost->max_sectors = sht->max_sectors;
 464         else
 465                 shost->max_sectors = SCSI_DEFAULT_MAX_SECTORS;
 466
 467         /*
 468          * assume a 4GB boundary, if not set
 469          */
 470         if (sht->dma_boundary)
 471                 shost->dma_boundary = sht->dma_boundary;
 472         else
 473                 shost->dma_boundary = 0xffffffff;
 474
 475         shost->use_blk_mq = scsi_use_blk_mq || shost->hostt->force_blk_mq;
 476
 477         device_initialize(&shost->shost_gendev);
 478         dev_set_name(&shost->shost_gendev, "host%d", shost->host_no);
 479         shost->shost_gendev.bus = &scsi_bus_type;
 480         shost->shost_gendev.type = &scsi_host_type;
 481
 482         device_initialize(&shost->shost_dev);
 483         shost->shost_dev.parent = &shost->shost_gendev;
 484         shost->shost_dev.class = &shost_class;
 485         dev_set_name(&shost->shost_dev, "host%d", shost->host_no);
 486         shost->shost_dev.groups = scsi_sysfs_shost_attr_groups;
 487
 488         shost->ehandler = kthread_run(scsi_error_handler, shost,
 489                         "scsi_eh_%d", shost->host_no);
 490         if (IS_ERR(shost->ehandler)) {
 491                 shost_printk(KERN_WARNING, shost,
 492                         "error handler thread failed to spawn, error = %ld\n",
 493                         PTR_ERR(shost->ehandler));
 494                 goto fail_index_remove;
 495         }
 496
 497         shost->tmf_work_q = alloc_workqueue("scsi_tmf_%d",
 498                                             WQ_UNBOUND | WQ_MEM_RECLAIM,
 499                                            1, shost->host_no);
 500         if (!shost->tmf_work_q) {
 501                 shost_printk(KERN_WARNING, shost,
 502                              "failed to create tmf workq\n");
 503                 goto fail_kthread;
 504         }
 505         scsi_proc_hostdir_add(shost->hostt);
 506         return shost;
 507
 508  fail_kthread:
 509         kthread_stop(shost->ehandler);
 510  fail_index_remove:
 511         ida_simple_remove(&host_index_ida, shost->host_no);
 512  fail_kfree:
 513         kfree(shost);
 514         return NULL;
 515 }
 516 EXPORT_SYMBOL(scsi_host_alloc);
 517
 518 static int __scsi_host_match(struct device *dev, const void *data)
 519 {
 520         struct Scsi_Host *p;
 521         const unsigned short *hostnum = data;
 522
 523         p = class_to_shost(dev);
 524         return p->host_no == *hostnum;
 525 }
 526
 527 /**
 528  * scsi_host_lookup - get a reference to a Scsi_Host by host no
 529  * @hostnum:    host number to locate
 530  *
 531  * Return value:
 532  *      A pointer to located Scsi_Host or NULL.
 533  *
 534  *      The caller must do a scsi_host_put() to drop the reference
 535  *      that scsi_host_get() took. The put_device() below dropped
 536  *      the reference from class_find_device().
 537  **/
 538 struct Scsi_Host *scsi_host_lookup(unsigned short hostnum)
 539 {
 540         struct device *cdev;
 541         struct Scsi_Host *shost = NULL;
 542
 543         cdev = class_find_device(&shost_class, NULL, &hostnum,
 544                                  __scsi_host_match);
 545         if (cdev) {
 546                 shost = scsi_host_get(class_to_shost(cdev));
 547                 put_device(cdev);
 548         }
 549         return shost;
 550 }
 551 EXPORT_SYMBOL(scsi_host_lookup);
 552
 553 /**
 554  * scsi_host_get - inc a Scsi_Host ref count
 555  * @shost:      Pointer to Scsi_Host to inc.
 556  **/
 557 struct Scsi_Host *scsi_host_get(struct Scsi_Host *shost)
 558 {
 559         if ((shost->shost_state == SHOST_DEL) ||
 560                 !get_device(&shost->shost_gendev))
 561                 return NULL;
 562         return shost;
 563 }
 564 EXPORT_SYMBOL(scsi_host_get);
 565
 566 struct scsi_host_mq_in_flight {
 567         int cnt;
 568 };
 569
 570 static void scsi_host_check_in_flight(struct request *rq, void *data,
 571                 bool reserved)
 572 {
 573         struct scsi_host_mq_in_flight *in_flight = data;
 574
 575         if (blk_mq_request_started(rq))
 576                 in_flight->cnt++;
 577 }
 578
 579 /**
 580  * scsi_host_busy - Return the host busy counter
 581  * @shost:      Pointer to Scsi_Host to inc.
 582  **/
 583 int scsi_host_busy(struct Scsi_Host *shost)
 584 {
 585         struct scsi_host_mq_in_flight in_flight = {
 586                 .cnt = 0,
 587         };
 588
 589         if (!shost->use_blk_mq)
 590                 return atomic_read(&shost->host_busy);
 591
 592         blk_mq_tagset_busy_iter(&shost->tag_set, scsi_host_check_in_flight,
 593                         &in_flight);
 594         return in_flight.cnt;
 595 }
 596 EXPORT_SYMBOL(scsi_host_busy);
 597
 598 /**
 599  * scsi_host_put - dec a Scsi_Host ref count
 600  * @shost:      Pointer to Scsi_Host to dec.
 601  **/
 602 void scsi_host_put(struct Scsi_Host *shost)
 603 {
 604         put_device(&shost->shost_gendev);
 605 }
 606 EXPORT_SYMBOL(scsi_host_put);
 607
 608 int scsi_init_hosts(void)
 609 {
 610         return class_register(&shost_class);
 611 }
 612
 613 void scsi_exit_hosts(void)
 614 {
 615         class_unregister(&shost_class);
 616         ida_destroy(&host_index_ida);
 617 }
 618
 619 int scsi_is_host_device(const struct device *dev)
 620 {
 621         return dev->type == &scsi_host_type;
 622 }
 623 EXPORT_SYMBOL(scsi_is_host_device);
 624
 625 /**
 626  * scsi_queue_work - Queue work to the Scsi_Host workqueue.
 627  * @shost:      Pointer to Scsi_Host.
 628  * @work:       Work to queue for execution.
 629  *
 630  * Return value:
 631  *      1 - work queued for execution
 632  *      0 - work is already queued
 633  *      -EINVAL - work queue doesn't exist
 634  **/
 635 int scsi_queue_work(struct Scsi_Host *shost, struct work_struct *work)
 636 {
 637         if (unlikely(!shost->work_q)) {
 638                 shost_printk(KERN_ERR, shost,
 639                         "ERROR: Scsi host '%s' attempted to queue scsi-work, "
 640                         "when no workqueue created.\n", shost->hostt->name);
 641                 dump_stack();
 642
 643                 return -EINVAL;
 644         }
 645
 646         return queue_work(shost->work_q, work);
 647 }
 648 EXPORT_SYMBOL_GPL(scsi_queue_work);
 649
 650 /**
 651  * scsi_flush_work - Flush a Scsi_Host's workqueue.
 652  * @shost:      Pointer to Scsi_Host.
 653  **/
 654 void scsi_flush_work(struct Scsi_Host *shost)
 655 {
 656         if (!shost->work_q) {
 657                 shost_printk(KERN_ERR, shost,
 658                         "ERROR: Scsi host '%s' attempted to flush scsi-work, "
 659                         "when no workqueue created.\n", shost->hostt->name);
 660                 dump_stack();
 661                 return;
 662         }
 663
 664         flush_workqueue(shost->work_q);
 665 }
 666 EXPORT_SYMBOL_GPL(scsi_flush_work);