drivers/scsi/hosts.c

   1 // SPDX-License-Identifier: GPL-2.0-only
   2 /*
   3  *  hosts.c Copyright (C) 1992 Drew Eckhardt
   4  *          Copyright (C) 1993, 1994, 1995 Eric Youngdale
   5  *          Copyright (C) 2002-2003 Christoph Hellwig
   6  *
   7  *  mid to lowlevel SCSI driver interface
   8  *      Initial versions: Drew Eckhardt
   9  *      Subsequent revisions: Eric Youngdale
  10  *
  11  *  <drew@colorado.edu>
  12  *
  13  *  Jiffies wrap fixes (host->resetting), 3 Dec 1998 Andrea Arcangeli
  14  *  Added QLOGIC QLA1280 SCSI controller kernel host support.
  15  *     August 4, 1999 Fred Lewis, Intel DuPont
  16  *
  17  *  Updated to reflect the new initialization scheme for the higher
  18  *  level of scsi drivers (sd/sr/st)
  19  *  September 17, 2000 Torben Mathiasen <tmm@image.dk>
  20  *
  21  *  Restructured scsi_host lists and associated functions.
  22  *  September 04, 2002 Mike Anderson (andmike@us.ibm.com)
  23  */
  24
  25 #include <linux/module.h>
  26 #include <linux/blkdev.h>
  27 #include <linux/kernel.h>
  28 #include <linux/slab.h>
  29 #include <linux/kthread.h>
  30 #include <linux/string.h>
  31 #include <linux/mm.h>
  32 #include <linux/init.h>
  33 #include <linux/completion.h>
  34 #include <linux/transport_class.h>
  35 #include <linux/platform_device.h>
  36 #include <linux/pm_runtime.h>
  37 #include <linux/idr.h>
  38 #include <scsi/scsi_device.h>
  39 #include <scsi/scsi_host.h>
  40 #include <scsi/scsi_transport.h>
  41
  42 #include "scsi_priv.h"
  43 #include "scsi_logging.h"
  44
  45
  46 static int shost_eh_deadline = -1;
  47
  48 module_param_named(eh_deadline, shost_eh_deadline, int, S_IRUGO|S_IWUSR);
  49 MODULE_PARM_DESC(eh_deadline,
  50                  "SCSI EH timeout in seconds (should be between 0 and 2^31-1)");
  51
  52 static DEFINE_IDA(host_index_ida);
  53
  54
  55 static void scsi_host_cls_release(struct device *dev)
  56 {
  57         put_device(&class_to_shost(dev)->shost_gendev);
  58 }
  59
  60 static struct class shost_class = {
  61         .name           = "scsi_host",
  62         .dev_release    = scsi_host_cls_release,
  63 };
  64
  65 /**
  66  *      scsi_host_set_state - Take the given host through the host state model.
  67  *      @shost: scsi host to change the state of.
  68  *      @state: state to change to.
  69  *
  70  *      Returns zero if unsuccessful or an error if the requested
  71  *      transition is illegal.
  72  **/
  73 int scsi_host_set_state(struct Scsi_Host *shost, enum scsi_host_state state)
  74 {
  75         enum scsi_host_state oldstate = shost->shost_state;
  76
  77         if (state == oldstate)
  78                 return 0;
  79
  80         switch (state) {
  81         case SHOST_CREATED:
  82                 /* There are no legal states that come back to
  83                  * created.  This is the manually initialised start
  84                  * state */
  85                 goto illegal;
  86
  87         case SHOST_RUNNING:
  88                 switch (oldstate) {
  89                 case SHOST_CREATED:
  90                 case SHOST_RECOVERY:
  91                         break;
  92                 default:
  93                         goto illegal;
  94                 }
  95                 break;
  96
  97         case SHOST_RECOVERY:
  98                 switch (oldstate) {
  99                 case SHOST_RUNNING:
 100                         break;
 101                 default:
 102                         goto illegal;
 103                 }
 104                 break;
 105
 106         case SHOST_CANCEL:
 107                 switch (oldstate) {
 108                 case SHOST_CREATED:
 109                 case SHOST_RUNNING:
 110                 case SHOST_CANCEL_RECOVERY:
 111                         break;
 112                 default:
 113                         goto illegal;
 114                 }
 115                 break;
 116
 117         case SHOST_DEL:
 118                 switch (oldstate) {
 119                 case SHOST_CANCEL:
 120                 case SHOST_DEL_RECOVERY:
 121                         break;
 122                 default:
 123                         goto illegal;
 124                 }
 125                 break;
 126
 127         case SHOST_CANCEL_RECOVERY:
 128                 switch (oldstate) {
 129                 case SHOST_CANCEL:
 130                 case SHOST_RECOVERY:
 131                         break;
 132                 default:
 133                         goto illegal;
 134                 }
 135                 break;
 136
 137         case SHOST_DEL_RECOVERY:
 138                 switch (oldstate) {
 139                 case SHOST_CANCEL_RECOVERY:
 140                         break;
 141                 default:
 142                         goto illegal;
 143                 }
 144                 break;
 145         }
 146         shost->shost_state = state;
 147         return 0;
 148
 149  illegal:
 150         SCSI_LOG_ERROR_RECOVERY(1,
 151                                 shost_printk(KERN_ERR, shost,
 152                                              "Illegal host state transition"
 153                                              "%s->%s\n",
 154                                              scsi_host_state_name(oldstate),
 155                                              scsi_host_state_name(state)));
 156         return -EINVAL;
 157 }
 158
 159 /**
 160  * scsi_remove_host - remove a scsi host
 161  * @shost:      a pointer to a scsi host to remove
 162  **/
 163 void scsi_remove_host(struct Scsi_Host *shost)
 164 {
 165         unsigned long flags;
 166
 167         mutex_lock(&shost->scan_mutex);
 168         spin_lock_irqsave(shost->host_lock, flags);
 169         if (scsi_host_set_state(shost, SHOST_CANCEL))
 170                 if (scsi_host_set_state(shost, SHOST_CANCEL_RECOVERY)) {
 171                         spin_unlock_irqrestore(shost->host_lock, flags);
 172                         mutex_unlock(&shost->scan_mutex);
 173                         return;
 174                 }
 175         spin_unlock_irqrestore(shost->host_lock, flags);
 176
 177         scsi_autopm_get_host(shost);
 178         flush_workqueue(shost->tmf_work_q);
 179         scsi_forget_host(shost);
 180         mutex_unlock(&shost->scan_mutex);
 181         scsi_proc_host_rm(shost);
 182         scsi_proc_hostdir_rm(shost->hostt);
 183
 184         spin_lock_irqsave(shost->host_lock, flags);
 185         if (scsi_host_set_state(shost, SHOST_DEL))
 186                 BUG_ON(scsi_host_set_state(shost, SHOST_DEL_RECOVERY));
 187         spin_unlock_irqrestore(shost->host_lock, flags);
 188
 189         transport_unregister_device(&shost->shost_gendev);
 190         device_unregister(&shost->shost_dev);
 191         device_del(&shost->shost_gendev);
 192 }
 193 EXPORT_SYMBOL(scsi_remove_host);
 194
 195 /**
 196  * scsi_add_host_with_dma - add a scsi host with dma device
 197  * @shost:      scsi host pointer to add
 198  * @dev:        a struct device of type scsi class
 199  * @dma_dev:    dma device for the host
 200  *
 201  * Note: You rarely need to worry about this unless you're in a
 202  * virtualised host environments, so use the simpler scsi_add_host()
 203  * function instead.
 204  *
 205  * Return value:
 206  *      0 on success / != 0 for error
 207  **/
 208 int scsi_add_host_with_dma(struct Scsi_Host *shost, struct device *dev,
 209                            struct device *dma_dev)
 210 {
 211         struct scsi_host_template *sht = shost->hostt;
 212         int error = -EINVAL;
 213
 214         shost_printk(KERN_INFO, shost, "%s\n",
 215                         sht->info ? sht->info(shost) : sht->name);
 216
 217         if (!shost->can_queue) {
 218                 shost_printk(KERN_ERR, shost,
 219                              "can_queue = 0 no longer supported\n");
 220                 goto fail;
 221         }
 222
 223         /* Use min_t(int, ...) in case shost->can_queue exceeds SHRT_MAX */
 224         shost->cmd_per_lun = min_t(int, shost->cmd_per_lun,
 225                                    shost->can_queue);
 226
 227         error = scsi_init_sense_cache(shost);
 228         if (error)
 229                 goto fail;
 230
 231         error = scsi_mq_setup_tags(shost);
 232         if (error)
 233                 goto fail;
 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         /*
 243          * Increase usage count temporarily here so that calling
 244          * scsi_autopm_put_host() will trigger runtime idle if there is
 245          * nothing else preventing suspending the device.
 246          */
 247         pm_runtime_get_noresume(&shost->shost_gendev);
 248         pm_runtime_set_active(&shost->shost_gendev);
 249         pm_runtime_enable(&shost->shost_gendev);
 250         device_enable_async_suspend(&shost->shost_gendev);
 251
 252         error = device_add(&shost->shost_gendev);
 253         if (error)
 254                 goto out_disable_runtime_pm;
 255
 256         scsi_host_set_state(shost, SHOST_RUNNING);
 257         get_device(shost->shost_gendev.parent);
 258
 259         device_enable_async_suspend(&shost->shost_dev);
 260
 261         get_device(&shost->shost_gendev);
 262         error = device_add(&shost->shost_dev);
 263         if (error)
 264                 goto out_del_gendev;
 265
 266         if (shost->transportt->host_size) {
 267                 shost->shost_data = kzalloc(shost->transportt->host_size,
 268                                          GFP_KERNEL);
 269                 if (shost->shost_data == NULL) {
 270                         error = -ENOMEM;
 271                         goto out_del_dev;
 272                 }
 273         }
 274
 275         if (shost->transportt->create_work_queue) {
 276                 snprintf(shost->work_q_name, sizeof(shost->work_q_name),
 277                          "scsi_wq_%d", shost->host_no);
 278                 shost->work_q = create_singlethread_workqueue(
 279                                         shost->work_q_name);
 280                 if (!shost->work_q) {
 281                         error = -EINVAL;
 282                         goto out_del_dev;
 283                 }
 284         }
 285
 286         error = scsi_sysfs_add_host(shost);
 287         if (error)
 288                 goto out_del_dev;
 289
 290         scsi_proc_host_add(shost);
 291         scsi_autopm_put_host(shost);
 292         return error;
 293
 294         /*
 295          * Any host allocation in this function will be freed in
 296          * scsi_host_dev_release().
 297          */
 298  out_del_dev:
 299         device_del(&shost->shost_dev);
 300  out_del_gendev:
 301         /*
 302          * Host state is SHOST_RUNNING so we have to explicitly release
 303          * ->shost_dev.
 304          */
 305         put_device(&shost->shost_dev);
 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  fail:
 313         return error;
 314 }
 315 EXPORT_SYMBOL(scsi_add_host_with_dma);
 316
 317 static void scsi_host_dev_release(struct device *dev)
 318 {
 319         struct Scsi_Host *shost = dev_to_shost(dev);
 320         struct device *parent = dev->parent;
 321
 322         /* Wait for functions invoked through call_rcu(&scmd->rcu, ...) */
 323         rcu_barrier();
 324
 325         if (shost->tmf_work_q)
 326                 destroy_workqueue(shost->tmf_work_q);
 327         if (shost->ehandler)
 328                 kthread_stop(shost->ehandler);
 329         if (shost->work_q)
 330                 destroy_workqueue(shost->work_q);
 331
 332         if (shost->shost_state == SHOST_CREATED) {
 333                 /*
 334                  * Free the shost_dev device name here if scsi_host_alloc()
 335                  * and scsi_host_put() have been called but neither
 336                  * scsi_host_add() nor scsi_host_remove() has been called.
 337                  * This avoids that the memory allocated for the shost_dev
 338                  * name is leaked.
 339                  */
 340                 kfree(dev_name(&shost->shost_dev));
 341         }
 342
 343         if (shost->tag_set.tags)
 344                 scsi_mq_destroy_tags(shost);
 345
 346         kfree(shost->shost_data);
 347
 348         ida_simple_remove(&host_index_ida, shost->host_no);
 349
 350         if (shost->shost_state != SHOST_CREATED)
 351                 put_device(parent);
 352         kfree(shost);
 353 }
 354
 355 static struct device_type scsi_host_type = {
 356         .name =         "scsi_host",
 357         .release =      scsi_host_dev_release,
 358 };
 359
 360 /**
 361  * scsi_host_alloc - register a scsi host adapter instance.
 362  * @sht:        pointer to scsi host template
 363  * @privsize:   extra bytes to allocate for driver
 364  *
 365  * Note:
 366  *      Allocate a new Scsi_Host and perform basic initialization.
 367  *      The host is not published to the scsi midlayer until scsi_add_host
 368  *      is called.
 369  *
 370  * Return value:
 371  *      Pointer to a new Scsi_Host
 372  **/
 373 struct Scsi_Host *scsi_host_alloc(struct scsi_host_template *sht, int privsize)
 374 {
 375         struct Scsi_Host *shost;
 376         gfp_t gfp_mask = GFP_KERNEL;
 377         int index;
 378
 379         if (sht->unchecked_isa_dma && privsize)
 380                 gfp_mask |= __GFP_DMA;
 381
 382         shost = kzalloc(sizeof(struct Scsi_Host) + privsize, gfp_mask);
 383         if (!shost)
 384                 return NULL;
 385
 386         shost->host_lock = &shost->default_lock;
 387         spin_lock_init(shost->host_lock);
 388         shost->shost_state = SHOST_CREATED;
 389         INIT_LIST_HEAD(&shost->__devices);
 390         INIT_LIST_HEAD(&shost->__targets);
 391         INIT_LIST_HEAD(&shost->eh_cmd_q);
 392         INIT_LIST_HEAD(&shost->starved_list);
 393         init_waitqueue_head(&shost->host_wait);
 394         mutex_init(&shost->scan_mutex);
 395
 396         index = ida_simple_get(&host_index_ida, 0, 0, GFP_KERNEL);
 397         if (index < 0) {
 398                 kfree(shost);
 399                 return NULL;
 400         }
 401         shost->host_no = index;
 402
 403         shost->dma_channel = 0xff;
 404
 405         /* These three are default values which can be overridden */
 406         shost->max_channel = 0;
 407         shost->max_id = 8;
 408         shost->max_lun = 8;
 409
 410         /* Give each shost a default transportt */
 411         shost->transportt = &blank_transport_template;
 412
 413         /*
 414          * All drivers right now should be able to handle 12 byte
 415          * commands.  Every so often there are requests for 16 byte
 416          * commands, but individual low-level drivers need to certify that
 417          * they actually do something sensible with such commands.
 418          */
 419         shost->max_cmd_len = 12;
 420         shost->hostt = sht;
 421         shost->this_id = sht->this_id;
 422         shost->can_queue = sht->can_queue;
 423         shost->sg_tablesize = sht->sg_tablesize;
 424         shost->sg_prot_tablesize = sht->sg_prot_tablesize;
 425         shost->cmd_per_lun = sht->cmd_per_lun;
 426         shost->unchecked_isa_dma = sht->unchecked_isa_dma;
 427         shost->no_write_same = sht->no_write_same;
 428
 429         if (shost_eh_deadline == -1 || !sht->eh_host_reset_handler)
 430                 shost->eh_deadline = -1;
 431         else if ((ulong) shost_eh_deadline * HZ > INT_MAX) {
 432                 shost_printk(KERN_WARNING, shost,
 433                              "eh_deadline %u too large, setting to %u\n",
 434                              shost_eh_deadline, INT_MAX / HZ);
 435                 shost->eh_deadline = INT_MAX;
 436         } else
 437                 shost->eh_deadline = shost_eh_deadline * HZ;
 438
 439         if (sht->supported_mode == MODE_UNKNOWN)
 440                 /* means we didn't set it ... default to INITIATOR */
 441                 shost->active_mode = MODE_INITIATOR;
 442         else
 443                 shost->active_mode = sht->supported_mode;
 444
 445         if (sht->max_host_blocked)
 446                 shost->max_host_blocked = sht->max_host_blocked;
 447         else
 448                 shost->max_host_blocked = SCSI_DEFAULT_HOST_BLOCKED;
 449
 450         /*
 451          * If the driver imposes no hard sector transfer limit, start at
 452          * machine infinity initially.
 453          */
 454         if (sht->max_sectors)
 455                 shost->max_sectors = sht->max_sectors;
 456         else
 457                 shost->max_sectors = SCSI_DEFAULT_MAX_SECTORS;
 458
 459         if (sht->max_segment_size)
 460                 shost->max_segment_size = sht->max_segment_size;
 461         else
 462                 shost->max_segment_size = BLK_MAX_SEGMENT_SIZE;
 463
 464         /*
 465          * assume a 4GB boundary, if not set
 466          */
 467         if (sht->dma_boundary)
 468                 shost->dma_boundary = sht->dma_boundary;
 469         else
 470                 shost->dma_boundary = 0xffffffff;
 471
 472         if (sht->virt_boundary_mask)
 473                 shost->virt_boundary_mask = sht->virt_boundary_mask;
 474
 475         device_initialize(&shost->shost_gendev);
 476         dev_set_name(&shost->shost_gendev, "host%d", shost->host_no);
 477         shost->shost_gendev.bus = &scsi_bus_type;
 478         shost->shost_gendev.type = &scsi_host_type;
 479
 480         device_initialize(&shost->shost_dev);
 481         shost->shost_dev.parent = &shost->shost_gendev;
 482         shost->shost_dev.class = &shost_class;
 483         dev_set_name(&shost->shost_dev, "host%d", shost->host_no);
 484         shost->shost_dev.groups = scsi_sysfs_shost_attr_groups;
 485
 486         shost->ehandler = kthread_run(scsi_error_handler, shost,
 487                         "scsi_eh_%d", shost->host_no);
 488         if (IS_ERR(shost->ehandler)) {
 489                 shost_printk(KERN_WARNING, shost,
 490                         "error handler thread failed to spawn, error = %ld\n",
 491                         PTR_ERR(shost->ehandler));
 492                 shost->ehandler = NULL;
 493                 goto fail;
 494         }
 495
 496         shost->tmf_work_q = alloc_workqueue("scsi_tmf_%d",
 497                                             WQ_UNBOUND | WQ_MEM_RECLAIM,
 498                                            1, shost->host_no);
 499         if (!shost->tmf_work_q) {
 500                 shost_printk(KERN_WARNING, shost,
 501                              "failed to create tmf workq\n");
 502                 goto fail;
 503         }
 504         scsi_proc_hostdir_add(shost->hostt);
 505         return shost;
 506  fail:
 507         /*
 508          * Host state is still SHOST_CREATED and that is enough to release
 509          * ->shost_gendev. scsi_host_dev_release() will free
 510          * dev_name(&shost->shost_dev).
 511          */
 512         put_device(&shost->shost_gendev);
 513
 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 /**
 567  * scsi_host_busy - Return the host busy counter
 568  * @shost:      Pointer to Scsi_Host to inc.
 569  **/
 570 int scsi_host_busy(struct Scsi_Host *shost)
 571 {
 572         return atomic_read(&shost->host_busy);
 573 }
 574 EXPORT_SYMBOL(scsi_host_busy);
 575
 576 /**
 577  * scsi_host_put - dec a Scsi_Host ref count
 578  * @shost:      Pointer to Scsi_Host to dec.
 579  **/
 580 void scsi_host_put(struct Scsi_Host *shost)
 581 {
 582         put_device(&shost->shost_gendev);
 583 }
 584 EXPORT_SYMBOL(scsi_host_put);
 585
 586 int scsi_init_hosts(void)
 587 {
 588         return class_register(&shost_class);
 589 }
 590
 591 void scsi_exit_hosts(void)
 592 {
 593         class_unregister(&shost_class);
 594         ida_destroy(&host_index_ida);
 595 }
 596
 597 int scsi_is_host_device(const struct device *dev)
 598 {
 599         return dev->type == &scsi_host_type;
 600 }
 601 EXPORT_SYMBOL(scsi_is_host_device);
 602
 603 /**
 604  * scsi_queue_work - Queue work to the Scsi_Host workqueue.
 605  * @shost:      Pointer to Scsi_Host.
 606  * @work:       Work to queue for execution.
 607  *
 608  * Return value:
 609  *      1 - work queued for execution
 610  *      0 - work is already queued
 611  *      -EINVAL - work queue doesn't exist
 612  **/
 613 int scsi_queue_work(struct Scsi_Host *shost, struct work_struct *work)
 614 {
 615         if (unlikely(!shost->work_q)) {
 616                 shost_printk(KERN_ERR, shost,
 617                         "ERROR: Scsi host '%s' attempted to queue scsi-work, "
 618                         "when no workqueue created.\n", shost->hostt->name);
 619                 dump_stack();
 620
 621                 return -EINVAL;
 622         }
 623
 624         return queue_work(shost->work_q, work);
 625 }
 626 EXPORT_SYMBOL_GPL(scsi_queue_work);
 627
 628 /**
 629  * scsi_flush_work - Flush a Scsi_Host's workqueue.
 630  * @shost:      Pointer to Scsi_Host.
 631  **/
 632 void scsi_flush_work(struct Scsi_Host *shost)
 633 {
 634         if (!shost->work_q) {
 635                 shost_printk(KERN_ERR, shost,
 636                         "ERROR: Scsi host '%s' attempted to flush scsi-work, "
 637                         "when no workqueue created.\n", shost->hostt->name);
 638                 dump_stack();
 639                 return;
 640         }
 641
 642         flush_workqueue(shost->work_q);
 643 }
 644 EXPORT_SYMBOL_GPL(scsi_flush_work);