linux/drivers/scsi/hosts.c
<<
>>
Prefs
   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/slab.h>
  28#include <linux/kthread.h>
  29#include <linux/string.h>
  30#include <linux/mm.h>
  31#include <linux/init.h>
  32#include <linux/completion.h>
  33#include <linux/transport_class.h>
  34#include <linux/platform_device.h>
  35#include <linux/pm_runtime.h>
  36
  37#include <scsi/scsi_device.h>
  38#include <scsi/scsi_host.h>
  39#include <scsi/scsi_transport.h>
  40
  41#include "scsi_priv.h"
  42#include "scsi_logging.h"
  43
  44
  45static atomic_t scsi_host_next_hn = ATOMIC_INIT(0);     /* host_no for next new host */
  46
  47
  48static void scsi_host_cls_release(struct device *dev)
  49{
  50        put_device(&class_to_shost(dev)->shost_gendev);
  51}
  52
  53static struct class shost_class = {
  54        .name           = "scsi_host",
  55        .dev_release    = scsi_host_cls_release,
  56};
  57
  58/**
  59 *      scsi_host_set_state - Take the given host through the host state model.
  60 *      @shost: scsi host to change the state of.
  61 *      @state: state to change to.
  62 *
  63 *      Returns zero if unsuccessful or an error if the requested
  64 *      transition is illegal.
  65 **/
  66int scsi_host_set_state(struct Scsi_Host *shost, enum scsi_host_state state)
  67{
  68        enum scsi_host_state oldstate = shost->shost_state;
  69
  70        if (state == oldstate)
  71                return 0;
  72
  73        switch (state) {
  74        case SHOST_CREATED:
  75                /* There are no legal states that come back to
  76                 * created.  This is the manually initialised start
  77                 * state */
  78                goto illegal;
  79
  80        case SHOST_RUNNING:
  81                switch (oldstate) {
  82                case SHOST_CREATED:
  83                case SHOST_RECOVERY:
  84                        break;
  85                default:
  86                        goto illegal;
  87                }
  88                break;
  89
  90        case SHOST_RECOVERY:
  91                switch (oldstate) {
  92                case SHOST_RUNNING:
  93                        break;
  94                default:
  95                        goto illegal;
  96                }
  97                break;
  98
  99        case SHOST_CANCEL:
 100                switch (oldstate) {
 101                case SHOST_CREATED:
 102                case SHOST_RUNNING:
 103                case SHOST_CANCEL_RECOVERY:
 104                        break;
 105                default:
 106                        goto illegal;
 107                }
 108                break;
 109
 110        case SHOST_DEL:
 111                switch (oldstate) {
 112                case SHOST_CANCEL:
 113                case SHOST_DEL_RECOVERY:
 114                        break;
 115                default:
 116                        goto illegal;
 117                }
 118                break;
 119
 120        case SHOST_CANCEL_RECOVERY:
 121                switch (oldstate) {
 122                case SHOST_CANCEL:
 123                case SHOST_RECOVERY:
 124                        break;
 125                default:
 126                        goto illegal;
 127                }
 128                break;
 129
 130        case SHOST_DEL_RECOVERY:
 131                switch (oldstate) {
 132                case SHOST_CANCEL_RECOVERY:
 133                        break;
 134                default:
 135                        goto illegal;
 136                }
 137                break;
 138        }
 139        shost->shost_state = state;
 140        return 0;
 141
 142 illegal:
 143        SCSI_LOG_ERROR_RECOVERY(1,
 144                                shost_printk(KERN_ERR, shost,
 145                                             "Illegal host state transition"
 146                                             "%s->%s\n",
 147                                             scsi_host_state_name(oldstate),
 148                                             scsi_host_state_name(state)));
 149        return -EINVAL;
 150}
 151EXPORT_SYMBOL(scsi_host_set_state);
 152
 153/**
 154 * scsi_remove_host - remove a scsi host
 155 * @shost:      a pointer to a scsi host to remove
 156 **/
 157void scsi_remove_host(struct Scsi_Host *shost)
 158{
 159        unsigned long flags;
 160
 161        mutex_lock(&shost->scan_mutex);
 162        spin_lock_irqsave(shost->host_lock, flags);
 163        if (scsi_host_set_state(shost, SHOST_CANCEL))
 164                if (scsi_host_set_state(shost, SHOST_CANCEL_RECOVERY)) {
 165                        spin_unlock_irqrestore(shost->host_lock, flags);
 166                        mutex_unlock(&shost->scan_mutex);
 167                        return;
 168                }
 169        spin_unlock_irqrestore(shost->host_lock, flags);
 170
 171        scsi_autopm_get_host(shost);
 172        scsi_forget_host(shost);
 173        mutex_unlock(&shost->scan_mutex);
 174        scsi_proc_host_rm(shost);
 175
 176        spin_lock_irqsave(shost->host_lock, flags);
 177        if (scsi_host_set_state(shost, SHOST_DEL))
 178                BUG_ON(scsi_host_set_state(shost, SHOST_DEL_RECOVERY));
 179        spin_unlock_irqrestore(shost->host_lock, flags);
 180
 181        transport_unregister_device(&shost->shost_gendev);
 182        device_unregister(&shost->shost_dev);
 183        device_del(&shost->shost_gendev);
 184}
 185EXPORT_SYMBOL(scsi_remove_host);
 186
 187/**
 188 * scsi_add_host_with_dma - add a scsi host with dma device
 189 * @shost:      scsi host pointer to add
 190 * @dev:        a struct device of type scsi class
 191 * @dma_dev:    dma device for the host
 192 *
 193 * Note: You rarely need to worry about this unless you're in a
 194 * virtualised host environments, so use the simpler scsi_add_host()
 195 * function instead.
 196 *
 197 * Return value: 
 198 *      0 on success / != 0 for error
 199 **/
 200int scsi_add_host_with_dma(struct Scsi_Host *shost, struct device *dev,
 201                           struct device *dma_dev)
 202{
 203        struct scsi_host_template *sht = shost->hostt;
 204        int error = -EINVAL;
 205
 206        printk(KERN_INFO "scsi%d : %s\n", shost->host_no,
 207                        sht->info ? sht->info(shost) : sht->name);
 208
 209        if (!shost->can_queue) {
 210                printk(KERN_ERR "%s: can_queue = 0 no longer supported\n",
 211                                sht->name);
 212                goto fail;
 213        }
 214
 215        error = scsi_setup_command_freelist(shost);
 216        if (error)
 217                goto fail;
 218
 219        if (!shost->shost_gendev.parent)
 220                shost->shost_gendev.parent = dev ? dev : &platform_bus;
 221        if (!dma_dev)
 222                dma_dev = shost->shost_gendev.parent;
 223
 224        shost->dma_dev = dma_dev;
 225
 226        error = device_add(&shost->shost_gendev);
 227        if (error)
 228                goto out;
 229
 230        pm_runtime_set_active(&shost->shost_gendev);
 231        pm_runtime_enable(&shost->shost_gendev);
 232        device_enable_async_suspend(&shost->shost_gendev);
 233
 234        scsi_host_set_state(shost, SHOST_RUNNING);
 235        get_device(shost->shost_gendev.parent);
 236
 237        device_enable_async_suspend(&shost->shost_dev);
 238
 239        error = device_add(&shost->shost_dev);
 240        if (error)
 241                goto out_del_gendev;
 242
 243        get_device(&shost->shost_gendev);
 244
 245        if (shost->transportt->host_size) {
 246                shost->shost_data = kzalloc(shost->transportt->host_size,
 247                                         GFP_KERNEL);
 248                if (shost->shost_data == NULL) {
 249                        error = -ENOMEM;
 250                        goto out_del_dev;
 251                }
 252        }
 253
 254        if (shost->transportt->create_work_queue) {
 255                snprintf(shost->work_q_name, sizeof(shost->work_q_name),
 256                         "scsi_wq_%d", shost->host_no);
 257                shost->work_q = create_singlethread_workqueue(
 258                                        shost->work_q_name);
 259                if (!shost->work_q) {
 260                        error = -EINVAL;
 261                        goto out_free_shost_data;
 262                }
 263        }
 264
 265        error = scsi_sysfs_add_host(shost);
 266        if (error)
 267                goto out_destroy_host;
 268
 269        scsi_proc_host_add(shost);
 270        return error;
 271
 272 out_destroy_host:
 273        if (shost->work_q)
 274                destroy_workqueue(shost->work_q);
 275 out_free_shost_data:
 276        kfree(shost->shost_data);
 277 out_del_dev:
 278        device_del(&shost->shost_dev);
 279 out_del_gendev:
 280        device_del(&shost->shost_gendev);
 281 out:
 282        scsi_destroy_command_freelist(shost);
 283 fail:
 284        return error;
 285}
 286EXPORT_SYMBOL(scsi_add_host_with_dma);
 287
 288static void scsi_host_dev_release(struct device *dev)
 289{
 290        struct Scsi_Host *shost = dev_to_shost(dev);
 291        struct device *parent = dev->parent;
 292        struct request_queue *q;
 293        void *queuedata;
 294
 295        scsi_proc_hostdir_rm(shost->hostt);
 296
 297        if (shost->ehandler)
 298                kthread_stop(shost->ehandler);
 299        if (shost->work_q)
 300                destroy_workqueue(shost->work_q);
 301        q = shost->uspace_req_q;
 302        if (q) {
 303                queuedata = q->queuedata;
 304                blk_cleanup_queue(q);
 305                kfree(queuedata);
 306        }
 307
 308        scsi_destroy_command_freelist(shost);
 309        if (shost->bqt)
 310                blk_free_tags(shost->bqt);
 311
 312        kfree(shost->shost_data);
 313
 314        if (parent)
 315                put_device(parent);
 316        kfree(shost);
 317}
 318
 319static struct device_type scsi_host_type = {
 320        .name =         "scsi_host",
 321        .release =      scsi_host_dev_release,
 322};
 323
 324/**
 325 * scsi_host_alloc - register a scsi host adapter instance.
 326 * @sht:        pointer to scsi host template
 327 * @privsize:   extra bytes to allocate for driver
 328 *
 329 * Note:
 330 *      Allocate a new Scsi_Host and perform basic initialization.
 331 *      The host is not published to the scsi midlayer until scsi_add_host
 332 *      is called.
 333 *
 334 * Return value:
 335 *      Pointer to a new Scsi_Host
 336 **/
 337struct Scsi_Host *scsi_host_alloc(struct scsi_host_template *sht, int privsize)
 338{
 339        struct Scsi_Host *shost;
 340        gfp_t gfp_mask = GFP_KERNEL;
 341
 342        if (sht->unchecked_isa_dma && privsize)
 343                gfp_mask |= __GFP_DMA;
 344
 345        shost = kzalloc(sizeof(struct Scsi_Host) + privsize, gfp_mask);
 346        if (!shost)
 347                return NULL;
 348
 349        shost->host_lock = &shost->default_lock;
 350        spin_lock_init(shost->host_lock);
 351        shost->shost_state = SHOST_CREATED;
 352        INIT_LIST_HEAD(&shost->__devices);
 353        INIT_LIST_HEAD(&shost->__targets);
 354        INIT_LIST_HEAD(&shost->eh_cmd_q);
 355        INIT_LIST_HEAD(&shost->starved_list);
 356        init_waitqueue_head(&shost->host_wait);
 357
 358        mutex_init(&shost->scan_mutex);
 359
 360        /*
 361         * subtract one because we increment first then return, but we need to
 362         * know what the next host number was before increment
 363         */
 364        shost->host_no = atomic_inc_return(&scsi_host_next_hn) - 1;
 365        shost->dma_channel = 0xff;
 366
 367        /* These three are default values which can be overridden */
 368        shost->max_channel = 0;
 369        shost->max_id = 8;
 370        shost->max_lun = 8;
 371
 372        /* Give each shost a default transportt */
 373        shost->transportt = &blank_transport_template;
 374
 375        /*
 376         * All drivers right now should be able to handle 12 byte
 377         * commands.  Every so often there are requests for 16 byte
 378         * commands, but individual low-level drivers need to certify that
 379         * they actually do something sensible with such commands.
 380         */
 381        shost->max_cmd_len = 12;
 382        shost->hostt = sht;
 383        shost->this_id = sht->this_id;
 384        shost->can_queue = sht->can_queue;
 385        shost->sg_tablesize = sht->sg_tablesize;
 386        shost->sg_prot_tablesize = sht->sg_prot_tablesize;
 387        shost->cmd_per_lun = sht->cmd_per_lun;
 388        shost->unchecked_isa_dma = sht->unchecked_isa_dma;
 389        shost->use_clustering = sht->use_clustering;
 390        shost->ordered_tag = sht->ordered_tag;
 391
 392        if (sht->supported_mode == MODE_UNKNOWN)
 393                /* means we didn't set it ... default to INITIATOR */
 394                shost->active_mode = MODE_INITIATOR;
 395        else
 396                shost->active_mode = sht->supported_mode;
 397
 398        if (sht->max_host_blocked)
 399                shost->max_host_blocked = sht->max_host_blocked;
 400        else
 401                shost->max_host_blocked = SCSI_DEFAULT_HOST_BLOCKED;
 402
 403        /*
 404         * If the driver imposes no hard sector transfer limit, start at
 405         * machine infinity initially.
 406         */
 407        if (sht->max_sectors)
 408                shost->max_sectors = sht->max_sectors;
 409        else
 410                shost->max_sectors = SCSI_DEFAULT_MAX_SECTORS;
 411
 412        /*
 413         * assume a 4GB boundary, if not set
 414         */
 415        if (sht->dma_boundary)
 416                shost->dma_boundary = sht->dma_boundary;
 417        else
 418                shost->dma_boundary = 0xffffffff;
 419
 420        device_initialize(&shost->shost_gendev);
 421        dev_set_name(&shost->shost_gendev, "host%d", shost->host_no);
 422        shost->shost_gendev.bus = &scsi_bus_type;
 423        shost->shost_gendev.type = &scsi_host_type;
 424
 425        device_initialize(&shost->shost_dev);
 426        shost->shost_dev.parent = &shost->shost_gendev;
 427        shost->shost_dev.class = &shost_class;
 428        dev_set_name(&shost->shost_dev, "host%d", shost->host_no);
 429        shost->shost_dev.groups = scsi_sysfs_shost_attr_groups;
 430
 431        shost->ehandler = kthread_run(scsi_error_handler, shost,
 432                        "scsi_eh_%d", shost->host_no);
 433        if (IS_ERR(shost->ehandler)) {
 434                printk(KERN_WARNING "scsi%d: error handler thread failed to spawn, error = %ld\n",
 435                        shost->host_no, PTR_ERR(shost->ehandler));
 436                goto fail_kfree;
 437        }
 438
 439        scsi_proc_hostdir_add(shost->hostt);
 440        return shost;
 441
 442 fail_kfree:
 443        kfree(shost);
 444        return NULL;
 445}
 446EXPORT_SYMBOL(scsi_host_alloc);
 447
 448struct Scsi_Host *scsi_register(struct scsi_host_template *sht, int privsize)
 449{
 450        struct Scsi_Host *shost = scsi_host_alloc(sht, privsize);
 451
 452        if (!sht->detect) {
 453                printk(KERN_WARNING "scsi_register() called on new-style "
 454                                    "template for driver %s\n", sht->name);
 455                dump_stack();
 456        }
 457
 458        if (shost)
 459                list_add_tail(&shost->sht_legacy_list, &sht->legacy_hosts);
 460        return shost;
 461}
 462EXPORT_SYMBOL(scsi_register);
 463
 464void scsi_unregister(struct Scsi_Host *shost)
 465{
 466        list_del(&shost->sht_legacy_list);
 467        scsi_host_put(shost);
 468}
 469EXPORT_SYMBOL(scsi_unregister);
 470
 471static int __scsi_host_match(struct device *dev, const void *data)
 472{
 473        struct Scsi_Host *p;
 474        const unsigned short *hostnum = data;
 475
 476        p = class_to_shost(dev);
 477        return p->host_no == *hostnum;
 478}
 479
 480/**
 481 * scsi_host_lookup - get a reference to a Scsi_Host by host no
 482 * @hostnum:    host number to locate
 483 *
 484 * Return value:
 485 *      A pointer to located Scsi_Host or NULL.
 486 *
 487 *      The caller must do a scsi_host_put() to drop the reference
 488 *      that scsi_host_get() took. The put_device() below dropped
 489 *      the reference from class_find_device().
 490 **/
 491struct Scsi_Host *scsi_host_lookup(unsigned short hostnum)
 492{
 493        struct device *cdev;
 494        struct Scsi_Host *shost = NULL;
 495
 496        cdev = class_find_device(&shost_class, NULL, &hostnum,
 497                                 __scsi_host_match);
 498        if (cdev) {
 499                shost = scsi_host_get(class_to_shost(cdev));
 500                put_device(cdev);
 501        }
 502        return shost;
 503}
 504EXPORT_SYMBOL(scsi_host_lookup);
 505
 506/**
 507 * scsi_host_get - inc a Scsi_Host ref count
 508 * @shost:      Pointer to Scsi_Host to inc.
 509 **/
 510struct Scsi_Host *scsi_host_get(struct Scsi_Host *shost)
 511{
 512        if ((shost->shost_state == SHOST_DEL) ||
 513                !get_device(&shost->shost_gendev))
 514                return NULL;
 515        return shost;
 516}
 517EXPORT_SYMBOL(scsi_host_get);
 518
 519/**
 520 * scsi_host_put - dec a Scsi_Host ref count
 521 * @shost:      Pointer to Scsi_Host to dec.
 522 **/
 523void scsi_host_put(struct Scsi_Host *shost)
 524{
 525        put_device(&shost->shost_gendev);
 526}
 527EXPORT_SYMBOL(scsi_host_put);
 528
 529int scsi_init_hosts(void)
 530{
 531        return class_register(&shost_class);
 532}
 533
 534void scsi_exit_hosts(void)
 535{
 536        class_unregister(&shost_class);
 537}
 538
 539int scsi_is_host_device(const struct device *dev)
 540{
 541        return dev->type == &scsi_host_type;
 542}
 543EXPORT_SYMBOL(scsi_is_host_device);
 544
 545/**
 546 * scsi_queue_work - Queue work to the Scsi_Host workqueue.
 547 * @shost:      Pointer to Scsi_Host.
 548 * @work:       Work to queue for execution.
 549 *
 550 * Return value:
 551 *      1 - work queued for execution
 552 *      0 - work is already queued
 553 *      -EINVAL - work queue doesn't exist
 554 **/
 555int scsi_queue_work(struct Scsi_Host *shost, struct work_struct *work)
 556{
 557        if (unlikely(!shost->work_q)) {
 558                printk(KERN_ERR
 559                        "ERROR: Scsi host '%s' attempted to queue scsi-work, "
 560                        "when no workqueue created.\n", shost->hostt->name);
 561                dump_stack();
 562
 563                return -EINVAL;
 564        }
 565
 566        return queue_work(shost->work_q, work);
 567}
 568EXPORT_SYMBOL_GPL(scsi_queue_work);
 569
 570/**
 571 * scsi_flush_work - Flush a Scsi_Host's workqueue.
 572 * @shost:      Pointer to Scsi_Host.
 573 **/
 574void scsi_flush_work(struct Scsi_Host *shost)
 575{
 576        if (!shost->work_q) {
 577                printk(KERN_ERR
 578                        "ERROR: Scsi host '%s' attempted to flush scsi-work, "
 579                        "when no workqueue created.\n", shost->hostt->name);
 580                dump_stack();
 581                return;
 582        }
 583
 584        flush_workqueue(shost->work_q);
 585}
 586EXPORT_SYMBOL_GPL(scsi_flush_work);
 587
lxr.linux.no kindly hosted by Redpill Linpro AS, provider of Linux consulting and operations services since 1995.