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/string.h>
  28 #include <linux/mm.h>
  29 #include <linux/init.h>
  30 #include <linux/completion.h>
  31 #include <linux/transport_class.h>
  32
  33 #include <scsi/scsi_device.h>
  34 #include <scsi/scsi_host.h>
  35 #include <scsi/scsi_transport.h>
  36
  37 #include "scsi_priv.h"
  38 #include "scsi_logging.h"
  39
  40
  41 static int scsi_host_next_hn;           /* host_no for next new host */
  42
  43
  44 static void scsi_host_cls_release(struct class_device *class_dev)
  45 {
  46         put_device(&class_to_shost(class_dev)->shost_gendev);
  47 }
  48
  49 static struct class shost_class = {
  50         .name           = "scsi_host",
  51         .release        = scsi_host_cls_release,
  52 };
  53
  54 /**
  55  *      scsi_host_set_state - Take the given host through the host
  56  *              state model.
  57  *      @shost: scsi host to change the state of.
  58  *      @state: state to change to.
  59  *
  60  *      Returns zero if unsuccessful or an error if the requested
  61  *      transition is illegal.
  62  **/
  63 int scsi_host_set_state(struct Scsi_Host *shost, enum scsi_host_state state)
  64 {
  65         enum scsi_host_state oldstate = shost->shost_state;
  66
  67         if (state == oldstate)
  68                 return 0;
  69
  70         switch (state) {
  71         case SHOST_CREATED:
  72                 /* There are no legal states that come back to
  73                  * created.  This is the manually initialised start
  74                  * state */
  75                 goto illegal;
  76
  77         case SHOST_RUNNING:
  78                 switch (oldstate) {
  79                 case SHOST_CREATED:
  80                 case SHOST_RECOVERY:
  81                         break;
  82                 default:
  83                         goto illegal;
  84                 }
  85                 break;
  86
  87         case SHOST_RECOVERY:
  88                 switch (oldstate) {
  89                 case SHOST_RUNNING:
  90                         break;
  91                 default:
  92                         goto illegal;
  93                 }
  94                 break;
  95
  96         case SHOST_CANCEL:
  97                 switch (oldstate) {
  98                 case SHOST_CREATED:
  99                 case SHOST_RUNNING:
 100                         break;
 101                 default:
 102                         goto illegal;
 103                 }
 104                 break;
 105
 106         case SHOST_DEL:
 107                 switch (oldstate) {
 108                 case SHOST_CANCEL:
 109                         break;
 110                 default:
 111                         goto illegal;
 112                 }
 113                 break;
 114
 115         }
 116         shost->shost_state = state;
 117         return 0;
 118
 119  illegal:
 120         SCSI_LOG_ERROR_RECOVERY(1,
 121                                 dev_printk(KERN_ERR, &shost->shost_gendev,
 122                                            "Illegal host state transition"
 123                                            "%s->%s\n",
 124                                            scsi_host_state_name(oldstate),
 125                                            scsi_host_state_name(state)));
 126         return -EINVAL;
 127 }
 128 EXPORT_SYMBOL(scsi_host_set_state);
 129
 130 /**
 131  * scsi_host_cancel - cancel outstanding IO to this host
 132  * @shost:      pointer to struct Scsi_Host
 133  * recovery:    recovery requested to run.
 134  **/
 135 static void scsi_host_cancel(struct Scsi_Host *shost, int recovery)
 136 {
 137         struct scsi_device *sdev;
 138
 139         scsi_host_set_state(shost, SHOST_CANCEL);
 140         shost_for_each_device(sdev, shost) {
 141                 scsi_device_cancel(sdev, recovery);
 142         }
 143         wait_event(shost->host_wait, (shost->shost_state != SHOST_RECOVERY));
 144 }
 145
 146 /**
 147  * scsi_remove_host - remove a scsi host
 148  * @shost:      a pointer to a scsi host to remove
 149  **/
 150 void scsi_remove_host(struct Scsi_Host *shost)
 151 {
 152         scsi_forget_host(shost);
 153         scsi_host_cancel(shost, 0);
 154         scsi_proc_host_rm(shost);
 155
 156         scsi_host_set_state(shost, SHOST_DEL);
 157
 158         transport_unregister_device(&shost->shost_gendev);
 159         class_device_unregister(&shost->shost_classdev);
 160         device_del(&shost->shost_gendev);
 161 }
 162 EXPORT_SYMBOL(scsi_remove_host);
 163
 164 /**
 165  * scsi_add_host - add a scsi host
 166  * @shost:      scsi host pointer to add
 167  * @dev:        a struct device of type scsi class
 168  *
 169  * Return value:
 170  *      0 on success / != 0 for error
 171  **/
 172 int scsi_add_host(struct Scsi_Host *shost, struct device *dev)
 173 {
 174         struct scsi_host_template *sht = shost->hostt;
 175         int error = -EINVAL;
 176
 177         printk(KERN_INFO "scsi%d : %s\n", shost->host_no,
 178                         sht->info ? sht->info(shost) : sht->name);
 179
 180         if (!shost->can_queue) {
 181                 printk(KERN_ERR "%s: can_queue = 0 no longer supported\n",
 182                                 sht->name);
 183                 goto out;
 184         }
 185
 186         if (!shost->shost_gendev.parent)
 187                 shost->shost_gendev.parent = dev ? dev : &platform_bus;
 188
 189         error = device_add(&shost->shost_gendev);
 190         if (error)
 191                 goto out;
 192
 193         scsi_host_set_state(shost, SHOST_RUNNING);
 194         get_device(shost->shost_gendev.parent);
 195
 196         error = class_device_add(&shost->shost_classdev);
 197         if (error)
 198                 goto out_del_gendev;
 199
 200         get_device(&shost->shost_gendev);
 201
 202         if (shost->transportt->host_size &&
 203             (shost->shost_data = kmalloc(shost->transportt->host_size,
 204                                          GFP_KERNEL)) == NULL)
 205                 goto out_del_classdev;
 206
 207         if (shost->transportt->create_work_queue) {
 208                 snprintf(shost->work_q_name, KOBJ_NAME_LEN, "scsi_wq_%d",
 209                         shost->host_no);
 210                 shost->work_q = create_singlethread_workqueue(
 211                                         shost->work_q_name);
 212                 if (!shost->work_q)
 213                         goto out_free_shost_data;
 214         }
 215
 216         error = scsi_sysfs_add_host(shost);
 217         if (error)
 218                 goto out_destroy_host;
 219
 220         scsi_proc_host_add(shost);
 221         return error;
 222
 223  out_destroy_host:
 224         if (shost->work_q)
 225                 destroy_workqueue(shost->work_q);
 226  out_free_shost_data:
 227         kfree(shost->shost_data);
 228  out_del_classdev:
 229         class_device_del(&shost->shost_classdev);
 230  out_del_gendev:
 231         device_del(&shost->shost_gendev);
 232  out:
 233         return error;
 234 }
 235 EXPORT_SYMBOL(scsi_add_host);
 236
 237 static void scsi_host_dev_release(struct device *dev)
 238 {
 239         struct Scsi_Host *shost = dev_to_shost(dev);
 240         struct device *parent = dev->parent;
 241
 242         if (shost->ehandler) {
 243                 DECLARE_COMPLETION(sem);
 244                 shost->eh_notify = &sem;
 245                 shost->eh_kill = 1;
 246                 up(shost->eh_wait);
 247                 wait_for_completion(&sem);
 248                 shost->eh_notify = NULL;
 249         }
 250
 251         if (shost->work_q)
 252                 destroy_workqueue(shost->work_q);
 253
 254         scsi_proc_hostdir_rm(shost->hostt);
 255         scsi_destroy_command_freelist(shost);
 256         kfree(shost->shost_data);
 257
 258         if (parent)
 259                 put_device(parent);
 260         kfree(shost);
 261 }
 262
 263 /**
 264  * scsi_host_alloc - register a scsi host adapter instance.
 265  * @sht:        pointer to scsi host template
 266  * @privsize:   extra bytes to allocate for driver
 267  *
 268  * Note:
 269  *      Allocate a new Scsi_Host and perform basic initialization.
 270  *      The host is not published to the scsi midlayer until scsi_add_host
 271  *      is called.
 272  *
 273  * Return value:
 274  *      Pointer to a new Scsi_Host
 275  **/
 276 struct Scsi_Host *scsi_host_alloc(struct scsi_host_template *sht, int privsize)
 277 {
 278         struct Scsi_Host *shost;
 279         int gfp_mask = GFP_KERNEL, rval;
 280         DECLARE_COMPLETION(complete);
 281
 282         if (sht->unchecked_isa_dma && privsize)
 283                 gfp_mask |= __GFP_DMA;
 284
 285         /* Check to see if this host has any error handling facilities */
 286         if (!sht->eh_strategy_handler && !sht->eh_abort_handler &&
 287             !sht->eh_device_reset_handler && !sht->eh_bus_reset_handler &&
 288             !sht->eh_host_reset_handler) {
 289                 printk(KERN_ERR "ERROR: SCSI host `%s' has no error handling\n"
 290                                 "ERROR: This is not a safe way to run your "
 291                                         "SCSI host\n"
 292                                 "ERROR: The error handling must be added to "
 293                                 "this driver\n", sht->proc_name);
 294                 dump_stack();
 295         }
 296
 297         shost = kmalloc(sizeof(struct Scsi_Host) + privsize, gfp_mask);
 298         if (!shost)
 299                 return NULL;
 300         memset(shost, 0, sizeof(struct Scsi_Host) + privsize);
 301
 302         spin_lock_init(&shost->default_lock);
 303         scsi_assign_lock(shost, &shost->default_lock);
 304         shost->shost_state = SHOST_CREATED;
 305         INIT_LIST_HEAD(&shost->__devices);
 306         INIT_LIST_HEAD(&shost->__targets);
 307         INIT_LIST_HEAD(&shost->eh_cmd_q);
 308         INIT_LIST_HEAD(&shost->starved_list);
 309         init_waitqueue_head(&shost->host_wait);
 310
 311         init_MUTEX(&shost->scan_mutex);
 312
 313         shost->host_no = scsi_host_next_hn++; /* XXX(hch): still racy */
 314         shost->dma_channel = 0xff;
 315
 316         /* These three are default values which can be overridden */
 317         shost->max_channel = 0;
 318         shost->max_id = 8;
 319         shost->max_lun = 8;
 320
 321         /* Give each shost a default transportt */
 322         shost->transportt = &blank_transport_template;
 323
 324         /*
 325          * All drivers right now should be able to handle 12 byte
 326          * commands.  Every so often there are requests for 16 byte
 327          * commands, but individual low-level drivers need to certify that
 328          * they actually do something sensible with such commands.
 329          */
 330         shost->max_cmd_len = 12;
 331         shost->hostt = sht;
 332         shost->this_id = sht->this_id;
 333         shost->can_queue = sht->can_queue;
 334         shost->sg_tablesize = sht->sg_tablesize;
 335         shost->cmd_per_lun = sht->cmd_per_lun;
 336         shost->unchecked_isa_dma = sht->unchecked_isa_dma;
 337         shost->use_clustering = sht->use_clustering;
 338         shost->ordered_flush = sht->ordered_flush;
 339         shost->ordered_tag = sht->ordered_tag;
 340
 341         /*
 342          * hosts/devices that do queueing must support ordered tags
 343          */
 344         if (shost->can_queue > 1 && shost->ordered_flush) {
 345                 printk(KERN_ERR "scsi: ordered flushes don't support queueing\n");
 346                 shost->ordered_flush = 0;
 347         }
 348
 349         if (sht->max_host_blocked)
 350                 shost->max_host_blocked = sht->max_host_blocked;
 351         else
 352                 shost->max_host_blocked = SCSI_DEFAULT_HOST_BLOCKED;
 353
 354         /*
 355          * If the driver imposes no hard sector transfer limit, start at
 356          * machine infinity initially.
 357          */
 358         if (sht->max_sectors)
 359                 shost->max_sectors = sht->max_sectors;
 360         else
 361                 shost->max_sectors = SCSI_DEFAULT_MAX_SECTORS;
 362
 363         /*
 364          * assume a 4GB boundary, if not set
 365          */
 366         if (sht->dma_boundary)
 367                 shost->dma_boundary = sht->dma_boundary;
 368         else
 369                 shost->dma_boundary = 0xffffffff;
 370
 371         rval = scsi_setup_command_freelist(shost);
 372         if (rval)
 373                 goto fail_kfree;
 374
 375         device_initialize(&shost->shost_gendev);
 376         snprintf(shost->shost_gendev.bus_id, BUS_ID_SIZE, "host%d",
 377                 shost->host_no);
 378         shost->shost_gendev.release = scsi_host_dev_release;
 379
 380         class_device_initialize(&shost->shost_classdev);
 381         shost->shost_classdev.dev = &shost->shost_gendev;
 382         shost->shost_classdev.class = &shost_class;
 383         snprintf(shost->shost_classdev.class_id, BUS_ID_SIZE, "host%d",
 384                   shost->host_no);
 385
 386         shost->eh_notify = &complete;
 387         rval = kernel_thread(scsi_error_handler, shost, 0);
 388         if (rval < 0)
 389                 goto fail_destroy_freelist;
 390         wait_for_completion(&complete);
 391         shost->eh_notify = NULL;
 392
 393         scsi_proc_hostdir_add(shost->hostt);
 394         return shost;
 395
 396  fail_destroy_freelist:
 397         scsi_destroy_command_freelist(shost);
 398  fail_kfree:
 399         kfree(shost);
 400         return NULL;
 401 }
 402 EXPORT_SYMBOL(scsi_host_alloc);
 403
 404 struct Scsi_Host *scsi_register(struct scsi_host_template *sht, int privsize)
 405 {
 406         struct Scsi_Host *shost = scsi_host_alloc(sht, privsize);
 407
 408         if (!sht->detect) {
 409                 printk(KERN_WARNING "scsi_register() called on new-style "
 410                                     "template for driver %s\n", sht->name);
 411                 dump_stack();
 412         }
 413
 414         if (shost)
 415                 list_add_tail(&shost->sht_legacy_list, &sht->legacy_hosts);
 416         return shost;
 417 }
 418 EXPORT_SYMBOL(scsi_register);
 419
 420 void scsi_unregister(struct Scsi_Host *shost)
 421 {
 422         list_del(&shost->sht_legacy_list);
 423         scsi_host_put(shost);
 424 }
 425 EXPORT_SYMBOL(scsi_unregister);
 426
 427 /**
 428  * scsi_host_lookup - get a reference to a Scsi_Host by host no
 429  *
 430  * @hostnum:    host number to locate
 431  *
 432  * Return value:
 433  *      A pointer to located Scsi_Host or NULL.
 434  **/
 435 struct Scsi_Host *scsi_host_lookup(unsigned short hostnum)
 436 {
 437         struct class *class = &shost_class;
 438         struct class_device *cdev;
 439         struct Scsi_Host *shost = ERR_PTR(-ENXIO), *p;
 440
 441         down_read(&class->subsys.rwsem);
 442         list_for_each_entry(cdev, &class->children, node) {
 443                 p = class_to_shost(cdev);
 444                 if (p->host_no == hostnum) {
 445                         shost = scsi_host_get(p);
 446                         break;
 447                 }
 448         }
 449         up_read(&class->subsys.rwsem);
 450
 451         return shost;
 452 }
 453 EXPORT_SYMBOL(scsi_host_lookup);
 454
 455 /**
 456  * scsi_host_get - inc a Scsi_Host ref count
 457  * @shost:      Pointer to Scsi_Host to inc.
 458  **/
 459 struct Scsi_Host *scsi_host_get(struct Scsi_Host *shost)
 460 {
 461         if ((shost->shost_state == SHOST_DEL) ||
 462                 !get_device(&shost->shost_gendev))
 463                 return NULL;
 464         return shost;
 465 }
 466 EXPORT_SYMBOL(scsi_host_get);
 467
 468 /**
 469  * scsi_host_put - dec a Scsi_Host ref count
 470  * @shost:      Pointer to Scsi_Host to dec.
 471  **/
 472 void scsi_host_put(struct Scsi_Host *shost)
 473 {
 474         put_device(&shost->shost_gendev);
 475 }
 476 EXPORT_SYMBOL(scsi_host_put);
 477
 478 int scsi_init_hosts(void)
 479 {
 480         return class_register(&shost_class);
 481 }
 482
 483 void scsi_exit_hosts(void)
 484 {
 485         class_unregister(&shost_class);
 486 }
 487
 488 int scsi_is_host_device(const struct device *dev)
 489 {
 490         return dev->release == scsi_host_dev_release;
 491 }
 492 EXPORT_SYMBOL(scsi_is_host_device);
 493
 494 /**
 495  * scsi_queue_work - Queue work to the Scsi_Host workqueue.
 496  * @shost:      Pointer to Scsi_Host.
 497  * @work:       Work to queue for execution.
 498  *
 499  * Return value:
 500  *      0 on success / != 0 for error
 501  **/
 502 int scsi_queue_work(struct Scsi_Host *shost, struct work_struct *work)
 503 {
 504         if (unlikely(!shost->work_q)) {
 505                 printk(KERN_ERR
 506                         "ERROR: Scsi host '%s' attempted to queue scsi-work, "
 507                         "when no workqueue created.\n", shost->hostt->name);
 508                 dump_stack();
 509
 510                 return -EINVAL;
 511         }
 512
 513         return queue_work(shost->work_q, work);
 514 }
 515 EXPORT_SYMBOL_GPL(scsi_queue_work);
 516
 517 /**
 518  * scsi_flush_work - Flush a Scsi_Host's workqueue.
 519  * @shost:      Pointer to Scsi_Host.
 520  **/
 521 void scsi_flush_work(struct Scsi_Host *shost)
 522 {
 523         if (!shost->work_q) {
 524                 printk(KERN_ERR
 525                         "ERROR: Scsi host '%s' attempted to flush scsi-work, "
 526                         "when no workqueue created.\n", shost->hostt->name);
 527                 dump_stack();
 528                 return;
 529         }
 530
 531         flush_workqueue(shost->work_q);
 532 }
 533 EXPORT_SYMBOL_GPL(scsi_flush_work);