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