hosts.c

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/*
 *  hosts.c Copyright (C) 1992 Drew Eckhardt
 *          Copyright (C) 1993, 1994, 1995 Eric Youngdale
 *          Copyright (C) 2002-2003 Christoph Hellwig
 *
 *  mid to lowlevel SCSI driver interface
 *      Initial versions: Drew Eckhardt
 *      Subsequent revisions: Eric Youngdale
 *
 *  <[email protected]>
 *
 *  Jiffies wrap fixes (host->resetting), 3 Dec 1998 Andrea Arcangeli
 *  Added QLOGIC QLA1280 SCSI controller kernel host support. 
 *     August 4, 1999 Fred Lewis, Intel DuPont
 *
 *  Updated to reflect the new initialization scheme for the higher 
 *  level of scsi drivers (sd/sr/st)
 *  September 17, 2000 Torben Mathiasen <[email protected]>
 *
 *  Restructured scsi_host lists and associated functions.
 *  September 04, 2002 Mike Anderson ([email protected])
 */

#include <linux/module.h>
#include <linux/blkdev.h>
#include <linux/kernel.h>
#include <linux/slab.h>
#include <linux/kthread.h>
#include <linux/string.h>
#include <linux/mm.h>
#include <linux/init.h>
#include <linux/completion.h>
#include <linux/transport_class.h>
#include <linux/platform_device.h>
#include <linux/pm_runtime.h>

#include <scsi/scsi_device.h>
#include <scsi/scsi_host.h>
#include <scsi/scsi_transport.h>

#include "scsi_priv.h"
#include "scsi_logging.h"


static atomic_t scsi_host_next_hn = ATOMIC_INIT(0); /* host_no for next new host */


static void scsi_host_cls_release(struct device *dev)
{
    put_device(&class_to_shost(dev)->shost_gendev);
}

static struct class shost_class = {
    .name       = "scsi_host",
    .dev_release    = scsi_host_cls_release,
};

int scsi_host_set_state(struct Scsi_Host *shost, enum scsi_host_state state)
{
    enum scsi_host_state oldstate = shost->shost_state;

    if (state == oldstate)
        return 0;

    switch (state) {
    case SHOST_CREATED:
        /* There are no legal states that come back to
         * created.  This is the manually initialised start
         * state */
        goto illegal;

    case SHOST_RUNNING:
        switch (oldstate) {
        case SHOST_CREATED:
        case SHOST_RECOVERY:
            break;
        default:
            goto illegal;
        }
        break;

    case SHOST_RECOVERY:
        switch (oldstate) {
        case SHOST_RUNNING:
            break;
        default:
            goto illegal;
        }
        break;

    case SHOST_CANCEL:
        switch (oldstate) {
        case SHOST_CREATED:
        case SHOST_RUNNING:
        case SHOST_CANCEL_RECOVERY:
            break;
        default:
            goto illegal;
        }
        break;

    case SHOST_DEL:
        switch (oldstate) {
        case SHOST_CANCEL:
        case SHOST_DEL_RECOVERY:
            break;
        default:
            goto illegal;
        }
        break;

    case SHOST_CANCEL_RECOVERY:
        switch (oldstate) {
        case SHOST_CANCEL:
        case SHOST_RECOVERY:
            break;
        default:
            goto illegal;
        }
        break;

    case SHOST_DEL_RECOVERY:
        switch (oldstate) {
        case SHOST_CANCEL_RECOVERY:
            break;
        default:
            goto illegal;
        }
        break;
    }
    shost->shost_state = state;
    return 0;

 illegal:
    SCSI_LOG_ERROR_RECOVERY(1,
                shost_printk(KERN_ERR, shost,
                         "Illegal host state transition"
                         "%s->%s\n",
                         scsi_host_state_name(oldstate),
                         scsi_host_state_name(state)));
    return -EINVAL;
}
EXPORT_SYMBOL(scsi_host_set_state);

void scsi_remove_host(struct Scsi_Host *shost)
{
    unsigned long flags;

    mutex_lock(&shost->scan_mutex);
    spin_lock_irqsave(shost->host_lock, flags);
    if (scsi_host_set_state(shost, SHOST_CANCEL))
        if (scsi_host_set_state(shost, SHOST_CANCEL_RECOVERY)) {
            spin_unlock_irqrestore(shost->host_lock, flags);
            mutex_unlock(&shost->scan_mutex);
            return;
        }
    spin_unlock_irqrestore(shost->host_lock, flags);

    scsi_autopm_get_host(shost);
    scsi_forget_host(shost);
    mutex_unlock(&shost->scan_mutex);
    scsi_proc_host_rm(shost);

    spin_lock_irqsave(shost->host_lock, flags);
    if (scsi_host_set_state(shost, SHOST_DEL))
        BUG_ON(scsi_host_set_state(shost, SHOST_DEL_RECOVERY));
    spin_unlock_irqrestore(shost->host_lock, flags);

    transport_unregister_device(&shost->shost_gendev);
    device_unregister(&shost->shost_dev);
    device_del(&shost->shost_gendev);
}
EXPORT_SYMBOL(scsi_remove_host);

int scsi_add_host_with_dma(struct Scsi_Host *shost, struct device *dev,
               struct device *dma_dev)
{
    struct scsi_host_template *sht = shost->hostt;
    int error = -EINVAL;

    printk(KERN_INFO "scsi%d : %s\n", shost->host_no,
            sht->info ? sht->info(shost) : sht->name);

    if (!shost->can_queue) {
        printk(KERN_ERR "%s: can_queue = 0 no longer supported\n",
                sht->name);
        goto fail;
    }

    error = scsi_setup_command_freelist(shost);
    if (error)
        goto fail;

    if (!shost->shost_gendev.parent)
        shost->shost_gendev.parent = dev ? dev : &platform_bus;
    if (!dma_dev)
        dma_dev = shost->shost_gendev.parent;

    shost->dma_dev = dma_dev;

    error = device_add(&shost->shost_gendev);
    if (error)
        goto out;

    pm_runtime_set_active(&shost->shost_gendev);
    pm_runtime_enable(&shost->shost_gendev);
    device_enable_async_suspend(&shost->shost_gendev);

    scsi_host_set_state(shost, SHOST_RUNNING);
    get_device(shost->shost_gendev.parent);

    device_enable_async_suspend(&shost->shost_dev);

    error = device_add(&shost->shost_dev);
    if (error)
        goto out_del_gendev;

    get_device(&shost->shost_gendev);

    if (shost->transportt->host_size) {
        shost->shost_data = kzalloc(shost->transportt->host_size,
                     GFP_KERNEL);
        if (shost->shost_data == NULL) {
            error = -ENOMEM;
            goto out_del_dev;
        }
    }

    if (shost->transportt->create_work_queue) {
        snprintf(shost->work_q_name, sizeof(shost->work_q_name),
             "scsi_wq_%d", shost->host_no);
        shost->work_q = create_singlethread_workqueue(
                    shost->work_q_name);
        if (!shost->work_q) {
            error = -EINVAL;
            goto out_free_shost_data;
        }
    }

    error = scsi_sysfs_add_host(shost);
    if (error)
        goto out_destroy_host;

    scsi_proc_host_add(shost);
    return error;

 out_destroy_host:
    if (shost->work_q)
        destroy_workqueue(shost->work_q);
 out_free_shost_data:
    kfree(shost->shost_data);
 out_del_dev:
    device_del(&shost->shost_dev);
 out_del_gendev:
    device_del(&shost->shost_gendev);
 out:
    scsi_destroy_command_freelist(shost);
 fail:
    return error;
}
EXPORT_SYMBOL(scsi_add_host_with_dma);

static void scsi_host_dev_release(struct device *dev)
{
    struct Scsi_Host *shost = dev_to_shost(dev);
    struct device *parent = dev->parent;
    struct request_queue *q;
    void *queuedata;

    scsi_proc_hostdir_rm(shost->hostt);

    if (shost->ehandler)
        kthread_stop(shost->ehandler);
    if (shost->work_q)
        destroy_workqueue(shost->work_q);
    q = shost->uspace_req_q;
    if (q) {
        queuedata = q->queuedata;
        blk_cleanup_queue(q);
        kfree(queuedata);
    }

    scsi_destroy_command_freelist(shost);
    if (shost->bqt)
        blk_free_tags(shost->bqt);

    kfree(shost->shost_data);

    if (parent)
        put_device(parent);
    kfree(shost);
}

static struct device_type scsi_host_type = {
    .name =     "scsi_host",
    .release =  scsi_host_dev_release,
};

struct Scsi_Host *scsi_host_alloc(struct scsi_host_template *sht, int privsize)
{
    struct Scsi_Host *shost;
    gfp_t gfp_mask = GFP_KERNEL;

    if (sht->unchecked_isa_dma && privsize)
        gfp_mask |= __GFP_DMA;

    shost = kzalloc(sizeof(struct Scsi_Host) + privsize, gfp_mask);
    if (!shost)
        return NULL;

    shost->host_lock = &shost->default_lock;
    spin_lock_init(shost->host_lock);
    shost->shost_state = SHOST_CREATED;
    INIT_LIST_HEAD(&shost->__devices);
    INIT_LIST_HEAD(&shost->__targets);
    INIT_LIST_HEAD(&shost->eh_cmd_q);
    INIT_LIST_HEAD(&shost->starved_list);
    init_waitqueue_head(&shost->host_wait);

    mutex_init(&shost->scan_mutex);

    /*
     * subtract one because we increment first then return, but we need to
     * know what the next host number was before increment
     */
    shost->host_no = atomic_inc_return(&scsi_host_next_hn) - 1;
    shost->dma_channel = 0xff;

    /* These three are default values which can be overridden */
    shost->max_channel = 0;
    shost->max_id = 8;
    shost->max_lun = 8;

    /* Give each shost a default transportt */
    shost->transportt = &blank_transport_template;

    /*
     * All drivers right now should be able to handle 12 byte
     * commands.  Every so often there are requests for 16 byte
     * commands, but individual low-level drivers need to certify that
     * they actually do something sensible with such commands.
     */
    shost->max_cmd_len = 12;
    shost->hostt = sht;
    shost->this_id = sht->this_id;
    shost->can_queue = sht->can_queue;
    shost->sg_tablesize = sht->sg_tablesize;
    shost->sg_prot_tablesize = sht->sg_prot_tablesize;
    shost->cmd_per_lun = sht->cmd_per_lun;
    shost->unchecked_isa_dma = sht->unchecked_isa_dma;
    shost->use_clustering = sht->use_clustering;
    shost->ordered_tag = sht->ordered_tag;

    if (sht->supported_mode == MODE_UNKNOWN)
        /* means we didn't set it ... default to INITIATOR */
        shost->active_mode = MODE_INITIATOR;
    else
        shost->active_mode = sht->supported_mode;

    if (sht->max_host_blocked)
        shost->max_host_blocked = sht->max_host_blocked;
    else
        shost->max_host_blocked = SCSI_DEFAULT_HOST_BLOCKED;

    /*
     * If the driver imposes no hard sector transfer limit, start at
     * machine infinity initially.
     */
    if (sht->max_sectors)
        shost->max_sectors = sht->max_sectors;
    else
        shost->max_sectors = SCSI_DEFAULT_MAX_SECTORS;

    /*
     * assume a 4GB boundary, if not set
     */
    if (sht->dma_boundary)
        shost->dma_boundary = sht->dma_boundary;
    else
        shost->dma_boundary = 0xffffffff;

    device_initialize(&shost->shost_gendev);
    dev_set_name(&shost->shost_gendev, "host%d", shost->host_no);
    shost->shost_gendev.bus = &scsi_bus_type;
    shost->shost_gendev.type = &scsi_host_type;

    device_initialize(&shost->shost_dev);
    shost->shost_dev.parent = &shost->shost_gendev;
    shost->shost_dev.class = &shost_class;
    dev_set_name(&shost->shost_dev, "host%d", shost->host_no);
    shost->shost_dev.groups = scsi_sysfs_shost_attr_groups;

    shost->ehandler = kthread_run(scsi_error_handler, shost,
            "scsi_eh_%d", shost->host_no);
    if (IS_ERR(shost->ehandler)) {
        printk(KERN_WARNING "scsi%d: error handler thread failed to spawn, error = %ld\n",
            shost->host_no, PTR_ERR(shost->ehandler));
        goto fail_kfree;
    }

    scsi_proc_hostdir_add(shost->hostt);
    return shost;

 fail_kfree:
    kfree(shost);
    return NULL;
}
EXPORT_SYMBOL(scsi_host_alloc);

struct Scsi_Host *scsi_register(struct scsi_host_template *sht, int privsize)
{
    struct Scsi_Host *shost = scsi_host_alloc(sht, privsize);

    if (!sht->detect) {
        printk(KERN_WARNING "scsi_register() called on new-style "
                    "template for driver %s\n", sht->name);
        dump_stack();
    }

    if (shost)
        list_add_tail(&shost->sht_legacy_list, &sht->legacy_hosts);
    return shost;
}
EXPORT_SYMBOL(scsi_register);

void scsi_unregister(struct Scsi_Host *shost)
{
    list_del(&shost->sht_legacy_list);
    scsi_host_put(shost);
}
EXPORT_SYMBOL(scsi_unregister);

static int __scsi_host_match(struct device *dev, void *data)
{
    struct Scsi_Host *p;
    unsigned short *hostnum = (unsigned short *)data;

    p = class_to_shost(dev);
    return p->host_no == *hostnum;
}

struct Scsi_Host *scsi_host_lookup(unsigned short hostnum)
{
    struct device *cdev;
    struct Scsi_Host *shost = NULL;

    cdev = class_find_device(&shost_class, NULL, &hostnum,
                 __scsi_host_match);
    if (cdev) {
        shost = scsi_host_get(class_to_shost(cdev));
        put_device(cdev);
    }
    return shost;
}
EXPORT_SYMBOL(scsi_host_lookup);

struct Scsi_Host *scsi_host_get(struct Scsi_Host *shost)
{
    if ((shost->shost_state == SHOST_DEL) ||
        !get_device(&shost->shost_gendev))
        return NULL;
    return shost;
}
EXPORT_SYMBOL(scsi_host_get);

void scsi_host_put(struct Scsi_Host *shost)
{
    put_device(&shost->shost_gendev);
}
EXPORT_SYMBOL(scsi_host_put);

int scsi_init_hosts(void)
{
    return class_register(&shost_class);
}

void scsi_exit_hosts(void)
{
    class_unregister(&shost_class);
}

int scsi_is_host_device(const struct device *dev)
{
    return dev->type == &scsi_host_type;
}
EXPORT_SYMBOL(scsi_is_host_device);

int scsi_queue_work(struct Scsi_Host *shost, struct work_struct *work)
{
    if (unlikely(!shost->work_q)) {
        printk(KERN_ERR
            "ERROR: Scsi host '%s' attempted to queue scsi-work, "
            "when no workqueue created.\n", shost->hostt->name);
        dump_stack();

        return -EINVAL;
    }

    return queue_work(shost->work_q, work);
}
EXPORT_SYMBOL_GPL(scsi_queue_work);

void scsi_flush_work(struct Scsi_Host *shost)
{
    if (!shost->work_q) {
        printk(KERN_ERR
            "ERROR: Scsi host '%s' attempted to flush scsi-work, "
            "when no workqueue created.\n", shost->hostt->name);
        dump_stack();
        return;
    }

    flush_workqueue(shost->work_q);
}
EXPORT_SYMBOL_GPL(scsi_flush_work);