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