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         kfree(shost->shost_data);
 269
 270         if (parent)
 271                 put_device(parent);
 272         kfree(shost);
 273 }
 274
 275 /**
 276  * scsi_host_alloc - register a scsi host adapter instance.
 277  * @sht:        pointer to scsi host template
 278  * @privsize:   extra bytes to allocate for driver
 279  *
 280  * Note:
 281  *      Allocate a new Scsi_Host and perform basic initialization.
 282  *      The host is not published to the scsi midlayer until scsi_add_host
 283  *      is called.
 284  *
 285  * Return value:
 286  *      Pointer to a new Scsi_Host
 287  **/
 288 struct Scsi_Host *scsi_host_alloc(struct scsi_host_template *sht, int privsize)
 289 {
 290         struct Scsi_Host *shost;
 291         gfp_t gfp_mask = GFP_KERNEL;
 292         int rval;
 293
 294         if (sht->unchecked_isa_dma && privsize)
 295                 gfp_mask |= __GFP_DMA;
 296
 297         /* Check to see if this host has any error handling facilities */
 298         if (!sht->eh_strategy_handler && !sht->eh_abort_handler &&
 299             !sht->eh_device_reset_handler && !sht->eh_bus_reset_handler &&
 300             !sht->eh_host_reset_handler) {
 301                 printk(KERN_ERR "ERROR: SCSI host `%s' has no error handling\n"
 302                                 "ERROR: This is not a safe way to run your "
 303                                         "SCSI host\n"
 304                                 "ERROR: The error handling must be added to "
 305                                 "this driver\n", sht->proc_name);
 306                 dump_stack();
 307         }
 308
 309         shost = kzalloc(sizeof(struct Scsi_Host) + privsize, gfp_mask);
 310         if (!shost)
 311                 return NULL;
 312
 313         spin_lock_init(&shost->default_lock);
 314         scsi_assign_lock(shost, &shost->default_lock);
 315         shost->shost_state = SHOST_CREATED;
 316         INIT_LIST_HEAD(&shost->__devices);
 317         INIT_LIST_HEAD(&shost->__targets);
 318         INIT_LIST_HEAD(&shost->eh_cmd_q);
 319         INIT_LIST_HEAD(&shost->starved_list);
 320         init_waitqueue_head(&shost->host_wait);
 321
 322         mutex_init(&shost->scan_mutex);
 323
 324         shost->host_no = scsi_host_next_hn++; /* XXX(hch): still racy */
 325         shost->dma_channel = 0xff;
 326
 327         /* These three are default values which can be overridden */
 328         shost->max_channel = 0;
 329         shost->max_id = 8;
 330         shost->max_lun = 8;
 331
 332         /* Give each shost a default transportt */
 333         shost->transportt = &blank_transport_template;
 334
 335         /*
 336          * All drivers right now should be able to handle 12 byte
 337          * commands.  Every so often there are requests for 16 byte
 338          * commands, but individual low-level drivers need to certify that
 339          * they actually do something sensible with such commands.
 340          */
 341         shost->max_cmd_len = 12;
 342         shost->hostt = sht;
 343         shost->this_id = sht->this_id;
 344         shost->can_queue = sht->can_queue;
 345         shost->sg_tablesize = sht->sg_tablesize;
 346         shost->cmd_per_lun = sht->cmd_per_lun;
 347         shost->unchecked_isa_dma = sht->unchecked_isa_dma;
 348         shost->use_clustering = sht->use_clustering;
 349         shost->ordered_tag = sht->ordered_tag;
 350
 351         if (sht->max_host_blocked)
 352                 shost->max_host_blocked = sht->max_host_blocked;
 353         else
 354                 shost->max_host_blocked = SCSI_DEFAULT_HOST_BLOCKED;
 355
 356         /*
 357          * If the driver imposes no hard sector transfer limit, start at
 358          * machine infinity initially.
 359          */
 360         if (sht->max_sectors)
 361                 shost->max_sectors = sht->max_sectors;
 362         else
 363                 shost->max_sectors = SCSI_DEFAULT_MAX_SECTORS;
 364
 365         /*
 366          * assume a 4GB boundary, if not set
 367          */
 368         if (sht->dma_boundary)
 369                 shost->dma_boundary = sht->dma_boundary;
 370         else
 371                 shost->dma_boundary = 0xffffffff;
 372
 373         rval = scsi_setup_command_freelist(shost);
 374         if (rval)
 375                 goto fail_kfree;
 376
 377         device_initialize(&shost->shost_gendev);
 378         snprintf(shost->shost_gendev.bus_id, BUS_ID_SIZE, "host%d",
 379                 shost->host_no);
 380         shost->shost_gendev.release = scsi_host_dev_release;
 381
 382         class_device_initialize(&shost->shost_classdev);
 383         shost->shost_classdev.dev = &shost->shost_gendev;
 384         shost->shost_classdev.class = &shost_class;
 385         snprintf(shost->shost_classdev.class_id, BUS_ID_SIZE, "host%d",
 386                   shost->host_no);
 387
 388         shost->ehandler = kthread_run(scsi_error_handler, shost,
 389                         "scsi_eh_%d", shost->host_no);
 390         if (IS_ERR(shost->ehandler)) {
 391                 rval = PTR_ERR(shost->ehandler);
 392                 goto fail_destroy_freelist;
 393         }
 394
 395         scsi_proc_hostdir_add(shost->hostt);
 396         return shost;
 397
 398  fail_destroy_freelist:
 399         scsi_destroy_command_freelist(shost);
 400  fail_kfree:
 401         kfree(shost);
 402         return NULL;
 403 }
 404 EXPORT_SYMBOL(scsi_host_alloc);
 405
 406 struct Scsi_Host *scsi_register(struct scsi_host_template *sht, int privsize)
 407 {
 408         struct Scsi_Host *shost = scsi_host_alloc(sht, privsize);
 409
 410         if (!sht->detect) {
 411                 printk(KERN_WARNING "scsi_register() called on new-style "
 412                                     "template for driver %s\n", sht->name);
 413                 dump_stack();
 414         }
 415
 416         if (shost)
 417                 list_add_tail(&shost->sht_legacy_list, &sht->legacy_hosts);
 418         return shost;
 419 }
 420 EXPORT_SYMBOL(scsi_register);
 421
 422 void scsi_unregister(struct Scsi_Host *shost)
 423 {
 424         list_del(&shost->sht_legacy_list);
 425         scsi_host_put(shost);
 426 }
 427 EXPORT_SYMBOL(scsi_unregister);
 428
 429 /**
 430  * scsi_host_lookup - get a reference to a Scsi_Host by host no
 431  *
 432  * @hostnum:    host number to locate
 433  *
 434  * Return value:
 435  *      A pointer to located Scsi_Host or NULL.
 436  **/
 437 struct Scsi_Host *scsi_host_lookup(unsigned short hostnum)
 438 {
 439         struct class *class = &shost_class;
 440         struct class_device *cdev;
 441         struct Scsi_Host *shost = ERR_PTR(-ENXIO), *p;
 442
 443         down_read(&class->subsys.rwsem);
 444         list_for_each_entry(cdev, &class->children, node) {
 445                 p = class_to_shost(cdev);
 446                 if (p->host_no == hostnum) {
 447                         shost = scsi_host_get(p);
 448                         break;
 449                 }
 450         }
 451         up_read(&class->subsys.rwsem);
 452
 453         return shost;
 454 }
 455 EXPORT_SYMBOL(scsi_host_lookup);
 456
 457 /**
 458  * scsi_host_get - inc a Scsi_Host ref count
 459  * @shost:      Pointer to Scsi_Host to inc.
 460  **/
 461 struct Scsi_Host *scsi_host_get(struct Scsi_Host *shost)
 462 {
 463         if ((shost->shost_state == SHOST_DEL) ||
 464                 !get_device(&shost->shost_gendev))
 465                 return NULL;
 466         return shost;
 467 }
 468 EXPORT_SYMBOL(scsi_host_get);
 469
 470 /**
 471  * scsi_host_put - dec a Scsi_Host ref count
 472  * @shost:      Pointer to Scsi_Host to dec.
 473  **/
 474 void scsi_host_put(struct Scsi_Host *shost)
 475 {
 476         put_device(&shost->shost_gendev);
 477 }
 478 EXPORT_SYMBOL(scsi_host_put);
 479
 480 int scsi_init_hosts(void)
 481 {
 482         return class_register(&shost_class);
 483 }
 484
 485 void scsi_exit_hosts(void)
 486 {
 487         class_unregister(&shost_class);
 488 }
 489
 490 int scsi_is_host_device(const struct device *dev)
 491 {
 492         return dev->release == scsi_host_dev_release;
 493 }
 494 EXPORT_SYMBOL(scsi_is_host_device);
 495
 496 /**
 497  * scsi_queue_work - Queue work to the Scsi_Host workqueue.
 498  * @shost:      Pointer to Scsi_Host.
 499  * @work:       Work to queue for execution.
 500  *
 501  * Return value:
 502  *      0 on success / != 0 for error
 503  **/
 504 int scsi_queue_work(struct Scsi_Host *shost, struct work_struct *work)
 505 {
 506         if (unlikely(!shost->work_q)) {
 507                 printk(KERN_ERR
 508                         "ERROR: Scsi host '%s' attempted to queue scsi-work, "
 509                         "when no workqueue created.\n", shost->hostt->name);
 510                 dump_stack();
 511
 512                 return -EINVAL;
 513         }
 514
 515         return queue_work(shost->work_q, work);
 516 }
 517 EXPORT_SYMBOL_GPL(scsi_queue_work);
 518
 519 /**
 520  * scsi_flush_work - Flush a Scsi_Host's workqueue.
 521  * @shost:      Pointer to Scsi_Host.
 522  **/
 523 void scsi_flush_work(struct Scsi_Host *shost)
 524 {
 525         if (!shost->work_q) {
 526                 printk(KERN_ERR
 527                         "ERROR: Scsi host '%s' attempted to flush scsi-work, "
 528                         "when no workqueue created.\n", shost->hostt->name);
 529                 dump_stack();
 530                 return;
 531         }
 532
 533         flush_workqueue(shost->work_q);
 534 }
 535 EXPORT_SYMBOL_GPL(scsi_flush_work);