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