dasd_devmap.c

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/*
 * Author(s)......: Holger Smolinski <[email protected]>
 *          Horst Hummel <[email protected]>
 *          Carsten Otte <[email protected]>
 *          Martin Schwidefsky <[email protected]>
 * Bugreports.to..: <[email protected]>
 * Copyright IBM Corp. 1999,2001
 *
 * Device mapping and dasd= parameter parsing functions. All devmap
 * functions may not be called from interrupt context. In particular
 * dasd_get_device is a no-no from interrupt context.
 *
 */

#define KMSG_COMPONENT "dasd"

#include <linux/ctype.h>
#include <linux/init.h>
#include <linux/module.h>
#include <linux/slab.h>

#include <asm/debug.h>
#include <asm/uaccess.h>
#include <asm/ipl.h>

/* This is ugly... */
#define PRINTK_HEADER "dasd_devmap:"
#define DASD_BUS_ID_SIZE 20

#include "dasd_int.h"

struct kmem_cache *dasd_page_cache;
EXPORT_SYMBOL_GPL(dasd_page_cache);

/*
 * dasd_devmap_t is used to store the features and the relation
 * between device number and device index. To find a dasd_devmap_t
 * that corresponds to a device number of a device index each
 * dasd_devmap_t is added to two linked lists, one to search by
 * the device number and one to search by the device index. As
 * soon as big minor numbers are available the device index list
 * can be removed since the device number will then be identical
 * to the device index.
 */
struct dasd_devmap {
    struct list_head list;
    char bus_id[DASD_BUS_ID_SIZE];
        unsigned int devindex;
        unsigned short features;
    struct dasd_device *device;
};

/*
 * Parameter parsing functions for dasd= parameter. The syntax is:
 *   <devno>        : (0x)?[0-9a-fA-F]+
 *   <busid>        : [0-0a-f]\.[0-9a-f]\.(0x)?[0-9a-fA-F]+
 *   <feature>      : ro
 *   <feature_list> : \(<feature>(:<feature>)*\)
 *   <devno-range>  : <devno>(-<devno>)?<feature_list>?
 *   <busid-range>  : <busid>(-<busid>)?<feature_list>?
 *   <devices>      : <devno-range>|<busid-range>
 *   <dasd_module>  : dasd_diag_mod|dasd_eckd_mod|dasd_fba_mod
 *
 *   <dasd>     : autodetect|probeonly|<devices>(,<devices>)*
 */

int dasd_probeonly =  0;    /* is true, when probeonly mode is active */
int dasd_autodetect = 0;    /* is true, when autodetection is active */
int dasd_nopav = 0;     /* is true, when PAV is disabled */
EXPORT_SYMBOL_GPL(dasd_nopav);
int dasd_nofcx;         /* disable High Performance Ficon */
EXPORT_SYMBOL_GPL(dasd_nofcx);

/*
 * char *dasd[] is intended to hold the ranges supplied by the dasd= statement
 * it is named 'dasd' to directly be filled by insmod with the comma separated
 * strings when running as a module.
 */
static char *dasd[256];
module_param_array(dasd, charp, NULL, 0);

/*
 * Single spinlock to protect devmap and servermap structures and lists.
 */
static DEFINE_SPINLOCK(dasd_devmap_lock);

/*
 * Hash lists for devmap structures.
 */
static struct list_head dasd_hashlists[256];
int dasd_max_devindex;

static struct dasd_devmap *dasd_add_busid(const char *, int);

static inline int
dasd_hash_busid(const char *bus_id)
{
    int hash, i;

    hash = 0;
    for (i = 0; (i < DASD_BUS_ID_SIZE) && *bus_id; i++, bus_id++)
        hash += *bus_id;
    return hash & 0xff;
}

#ifndef MODULE
/*
 * The parameter parsing functions for builtin-drivers are called
 * before kmalloc works. Store the pointers to the parameters strings
 * into dasd[] for later processing.
 */
static int __init
dasd_call_setup(char *str)
{
    static int count = 0;

    if (count < 256)
        dasd[count++] = str;
    return 1;
}

__setup ("dasd=", dasd_call_setup);
#endif  /* #ifndef MODULE */

#define DASD_IPLDEV "ipldev"

/*
 * Read a device busid/devno from a string.
 */
static int

dasd_busid(char **str, int *id0, int *id1, int *devno)
{
    int val, old_style;

    /* Interpret ipldev busid */
    if (strncmp(DASD_IPLDEV, *str, strlen(DASD_IPLDEV)) == 0) {
        if (ipl_info.type != IPL_TYPE_CCW) {
            pr_err("The IPL device is not a CCW device\n");
            return -EINVAL;
        }
        *id0 = 0;
        *id1 = ipl_info.data.ccw.dev_id.ssid;
        *devno = ipl_info.data.ccw.dev_id.devno;
        *str += strlen(DASD_IPLDEV);

        return 0;
    }
    /* check for leading '0x' */
    old_style = 0;
    if ((*str)[0] == '0' && (*str)[1] == 'x') {
        *str += 2;
        old_style = 1;
    }
    if (!isxdigit((*str)[0]))   /* We require at least one hex digit */
        return -EINVAL;
    val = simple_strtoul(*str, str, 16);
    if (old_style || (*str)[0] != '.') {
        *id0 = *id1 = 0;
        if (val < 0 || val > 0xffff)
            return -EINVAL;
        *devno = val;
        return 0;
    }
    /* New style x.y.z busid */
    if (val < 0 || val > 0xff)
        return -EINVAL;
    *id0 = val;
    (*str)++;
    if (!isxdigit((*str)[0]))   /* We require at least one hex digit */
        return -EINVAL;
    val = simple_strtoul(*str, str, 16);
    if (val < 0 || val > 0xff || (*str)++[0] != '.')
        return -EINVAL;
    *id1 = val;
    if (!isxdigit((*str)[0]))   /* We require at least one hex digit */
        return -EINVAL;
    val = simple_strtoul(*str, str, 16);
    if (val < 0 || val > 0xffff)
        return -EINVAL;
    *devno = val;
    return 0;
}

/*
 * Read colon separated list of dasd features. Currently there is
 * only one: "ro" for read-only devices. The default feature set
 * is empty (value 0).
 */
static int
dasd_feature_list(char *str, char **endp)
{
    int features, len, rc;

    rc = 0;
    if (*str != '(') {
        *endp = str;
        return DASD_FEATURE_DEFAULT;
    }
    str++;
    features = 0;

    while (1) {
        for (len = 0;
             str[len] && str[len] != ':' && str[len] != ')'; len++);
        if (len == 2 && !strncmp(str, "ro", 2))
            features |= DASD_FEATURE_READONLY;
        else if (len == 4 && !strncmp(str, "diag", 4))
            features |= DASD_FEATURE_USEDIAG;
        else if (len == 3 && !strncmp(str, "raw", 3))
            features |= DASD_FEATURE_USERAW;
        else if (len == 6 && !strncmp(str, "erplog", 6))
            features |= DASD_FEATURE_ERPLOG;
        else if (len == 8 && !strncmp(str, "failfast", 8))
            features |= DASD_FEATURE_FAILFAST;
        else {
            pr_warning("%*s is not a supported device option\n",
                   len, str);
            rc = -EINVAL;
        }
        str += len;
        if (*str != ':')
            break;
        str++;
    }
    if (*str != ')') {
        pr_warning("A closing parenthesis ')' is missing in the "
               "dasd= parameter\n");
        rc = -EINVAL;
    } else
        str++;
    *endp = str;
    if (rc != 0)
        return rc;
    return features;
}

/*
 * Try to match the first element on the comma separated parse string
 * with one of the known keywords. If a keyword is found, take the approprate
 * action and return a pointer to the residual string. If the first element
 * could not be matched to any keyword then return an error code.
 */
static char *
dasd_parse_keyword( char *parsestring ) {

    char *nextcomma, *residual_str;
    int length;

    nextcomma = strchr(parsestring,',');
    if (nextcomma) {
        length = nextcomma - parsestring;
        residual_str = nextcomma + 1;
    } else {
        length = strlen(parsestring);
        residual_str = parsestring + length;
        }
    if (strncmp("autodetect", parsestring, length) == 0) {
        dasd_autodetect = 1;
        pr_info("The autodetection mode has been activated\n");
                return residual_str;
        }
    if (strncmp("probeonly", parsestring, length) == 0) {
        dasd_probeonly = 1;
        pr_info("The probeonly mode has been activated\n");
                return residual_str;
        }
    if (strncmp("nopav", parsestring, length) == 0) {
        if (MACHINE_IS_VM)
            pr_info("'nopav' is not supported on z/VM\n");
        else {
            dasd_nopav = 1;
            pr_info("PAV support has be deactivated\n");
        }
        return residual_str;
    }
    if (strncmp("nofcx", parsestring, length) == 0) {
        dasd_nofcx = 1;
        pr_info("High Performance FICON support has been "
            "deactivated\n");
        return residual_str;
    }
    if (strncmp("fixedbuffers", parsestring, length) == 0) {
        if (dasd_page_cache)
            return residual_str;
        dasd_page_cache =
            kmem_cache_create("dasd_page_cache", PAGE_SIZE,
                      PAGE_SIZE, SLAB_CACHE_DMA,
                      NULL);
        if (!dasd_page_cache)
            DBF_EVENT(DBF_WARNING, "%s", "Failed to create slab, "
                "fixed buffer mode disabled.");
        else
            DBF_EVENT(DBF_INFO, "%s",
                 "turning on fixed buffer mode");
                return residual_str;
        }
    return ERR_PTR(-EINVAL);
}

/*
 * Try to interprete the first element on the comma separated parse string
 * as a device number or a range of devices. If the interpretation is
 * successful, create the matching dasd_devmap entries and return a pointer
 * to the residual string.
 * If interpretation fails or in case of an error, return an error code.
 */
static char *
dasd_parse_range( char *parsestring ) {

    struct dasd_devmap *devmap;
    int from, from_id0, from_id1;
    int to, to_id0, to_id1;
    int features, rc;
    char bus_id[DASD_BUS_ID_SIZE+1], *str;

    str = parsestring;
    rc = dasd_busid(&str, &from_id0, &from_id1, &from);
    if (rc == 0) {
        to = from;
        to_id0 = from_id0;
        to_id1 = from_id1;
        if (*str == '-') {
            str++;
            rc = dasd_busid(&str, &to_id0, &to_id1, &to);
        }
    }
    if (rc == 0 &&
        (from_id0 != to_id0 || from_id1 != to_id1 || from > to))
        rc = -EINVAL;
    if (rc) {
        pr_err("%s is not a valid device range\n", parsestring);
        return ERR_PTR(rc);
    }
    features = dasd_feature_list(str, &str);
    if (features < 0)
        return ERR_PTR(-EINVAL);
    /* each device in dasd= parameter should be set initially online */
    features |= DASD_FEATURE_INITIAL_ONLINE;
    while (from <= to) {
        sprintf(bus_id, "%01x.%01x.%04x",
            from_id0, from_id1, from++);
        devmap = dasd_add_busid(bus_id, features);
        if (IS_ERR(devmap))
            return (char *)devmap;
    }
    if (*str == ',')
        return str + 1;
    if (*str == '\0')
        return str;
    pr_warning("The dasd= parameter value %s has an invalid ending\n",
           str);
    return ERR_PTR(-EINVAL);
}

static char *
dasd_parse_next_element( char *parsestring ) {
    char * residual_str;
    residual_str = dasd_parse_keyword(parsestring);
    if (!IS_ERR(residual_str))
        return residual_str;
    residual_str = dasd_parse_range(parsestring);
    return residual_str;
}

/*
 * Parse parameters stored in dasd[]
 * The 'dasd=...' parameter allows to specify a comma separated list of
 * keywords and device ranges. When the dasd driver is build into the kernel,
 * the complete list will be stored as one element of the dasd[] array.
 * When the dasd driver is build as a module, then the list is broken into
 * it's elements and each dasd[] entry contains one element.
 */
int
dasd_parse(void)
{
    int rc, i;
    char *parsestring;

    rc = 0;
    for (i = 0; i < 256; i++) {
        if (dasd[i] == NULL)
            break;
        parsestring = dasd[i];
        /* loop over the comma separated list in the parsestring */
        while (*parsestring) {
            parsestring = dasd_parse_next_element(parsestring);
            if(IS_ERR(parsestring)) {
                rc = PTR_ERR(parsestring);
                break;
            }
        }
        if (rc) {
            DBF_EVENT(DBF_ALERT, "%s", "invalid range found");
            break;
        }
    }
    return rc;
}

/*
 * Add a devmap for the device specified by busid. It is possible that
 * the devmap already exists (dasd= parameter). The order of the devices
 * added through this function will define the kdevs for the individual
 * devices.
 */
static struct dasd_devmap *
dasd_add_busid(const char *bus_id, int features)
{
    struct dasd_devmap *devmap, *new, *tmp;
    int hash;

    new = (struct dasd_devmap *)
        kzalloc(sizeof(struct dasd_devmap), GFP_KERNEL);
    if (!new)
        return ERR_PTR(-ENOMEM);
    spin_lock(&dasd_devmap_lock);
    devmap = NULL;
    hash = dasd_hash_busid(bus_id);
    list_for_each_entry(tmp, &dasd_hashlists[hash], list)
        if (strncmp(tmp->bus_id, bus_id, DASD_BUS_ID_SIZE) == 0) {
            devmap = tmp;
            break;
        }
    if (!devmap) {
        /* This bus_id is new. */
        new->devindex = dasd_max_devindex++;
        strncpy(new->bus_id, bus_id, DASD_BUS_ID_SIZE);
        new->features = features;
        new->device = NULL;
        list_add(&new->list, &dasd_hashlists[hash]);
        devmap = new;
        new = NULL;
    }
    spin_unlock(&dasd_devmap_lock);
    kfree(new);
    return devmap;
}

/*
 * Find devmap for device with given bus_id.
 */
static struct dasd_devmap *
dasd_find_busid(const char *bus_id)
{
    struct dasd_devmap *devmap, *tmp;
    int hash;

    spin_lock(&dasd_devmap_lock);
    devmap = ERR_PTR(-ENODEV);
    hash = dasd_hash_busid(bus_id);
    list_for_each_entry(tmp, &dasd_hashlists[hash], list) {
        if (strncmp(tmp->bus_id, bus_id, DASD_BUS_ID_SIZE) == 0) {
            devmap = tmp;
            break;
        }
    }
    spin_unlock(&dasd_devmap_lock);
    return devmap;
}

/*
 * Check if busid has been added to the list of dasd ranges.
 */
int
dasd_busid_known(const char *bus_id)
{
    return IS_ERR(dasd_find_busid(bus_id)) ? -ENOENT : 0;
}

/*
 * Forget all about the device numbers added so far.
 * This may only be called at module unload or system shutdown.
 */
static void
dasd_forget_ranges(void)
{
    struct dasd_devmap *devmap, *n;
    int i;

    spin_lock(&dasd_devmap_lock);
    for (i = 0; i < 256; i++) {
        list_for_each_entry_safe(devmap, n, &dasd_hashlists[i], list) {
            BUG_ON(devmap->device != NULL);
            list_del(&devmap->list);
            kfree(devmap);
        }
    }
    spin_unlock(&dasd_devmap_lock);
}

/*
 * Find the device struct by its device index.
 */
struct dasd_device *
dasd_device_from_devindex(int devindex)
{
    struct dasd_devmap *devmap, *tmp;
    struct dasd_device *device;
    int i;

    spin_lock(&dasd_devmap_lock);
    devmap = NULL;
    for (i = 0; (i < 256) && !devmap; i++)
        list_for_each_entry(tmp, &dasd_hashlists[i], list)
            if (tmp->devindex == devindex) {
                /* Found the devmap for the device. */
                devmap = tmp;
                break;
            }
    if (devmap && devmap->device) {
        device = devmap->device;
        dasd_get_device(device);
    } else
        device = ERR_PTR(-ENODEV);
    spin_unlock(&dasd_devmap_lock);
    return device;
}

/*
 * Return devmap for cdev. If no devmap exists yet, create one and
 * connect it to the cdev.
 */
static struct dasd_devmap *
dasd_devmap_from_cdev(struct ccw_device *cdev)
{
    struct dasd_devmap *devmap;

    devmap = dasd_find_busid(dev_name(&cdev->dev));
    if (IS_ERR(devmap))
        devmap = dasd_add_busid(dev_name(&cdev->dev),
                    DASD_FEATURE_DEFAULT);
    return devmap;
}

/*
 * Create a dasd device structure for cdev.
 */
struct dasd_device *
dasd_create_device(struct ccw_device *cdev)
{
    struct dasd_devmap *devmap;
    struct dasd_device *device;
    unsigned long flags;
    int rc;

    devmap = dasd_devmap_from_cdev(cdev);
    if (IS_ERR(devmap))
        return (void *) devmap;

    device = dasd_alloc_device();
    if (IS_ERR(device))
        return device;
    atomic_set(&device->ref_count, 3);

    spin_lock(&dasd_devmap_lock);
    if (!devmap->device) {
        devmap->device = device;
        device->devindex = devmap->devindex;
        device->features = devmap->features;
        get_device(&cdev->dev);
        device->cdev = cdev;
        rc = 0;
    } else
        /* Someone else was faster. */
        rc = -EBUSY;
    spin_unlock(&dasd_devmap_lock);

    if (rc) {
        dasd_free_device(device);
        return ERR_PTR(rc);
    }

    spin_lock_irqsave(get_ccwdev_lock(cdev), flags);
    dev_set_drvdata(&cdev->dev, device);
    spin_unlock_irqrestore(get_ccwdev_lock(cdev), flags);

    return device;
}

/*
 * Wait queue for dasd_delete_device waits.
 */
static DECLARE_WAIT_QUEUE_HEAD(dasd_delete_wq);

/*
 * Remove a dasd device structure. The passed referenced
 * is destroyed.
 */
void
dasd_delete_device(struct dasd_device *device)
{
    struct ccw_device *cdev;
    struct dasd_devmap *devmap;
    unsigned long flags;

    /* First remove device pointer from devmap. */
    devmap = dasd_find_busid(dev_name(&device->cdev->dev));
    BUG_ON(IS_ERR(devmap));
    spin_lock(&dasd_devmap_lock);
    if (devmap->device != device) {
        spin_unlock(&dasd_devmap_lock);
        dasd_put_device(device);
        return;
    }
    devmap->device = NULL;
    spin_unlock(&dasd_devmap_lock);

    /* Disconnect dasd_device structure from ccw_device structure. */
    spin_lock_irqsave(get_ccwdev_lock(device->cdev), flags);
    dev_set_drvdata(&device->cdev->dev, NULL);
    spin_unlock_irqrestore(get_ccwdev_lock(device->cdev), flags);

    /*
     * Drop ref_count by 3, one for the devmap reference, one for
     * the cdev reference and one for the passed reference.
     */
    atomic_sub(3, &device->ref_count);

    /* Wait for reference counter to drop to zero. */
    wait_event(dasd_delete_wq, atomic_read(&device->ref_count) == 0);

    /* Disconnect dasd_device structure from ccw_device structure. */
    cdev = device->cdev;
    device->cdev = NULL;

    /* Put ccw_device structure. */
    put_device(&cdev->dev);

    /* Now the device structure can be freed. */
    dasd_free_device(device);
}

/*
 * Reference counter dropped to zero. Wake up waiter
 * in dasd_delete_device.
 */
void
dasd_put_device_wake(struct dasd_device *device)
{
    wake_up(&dasd_delete_wq);
}
EXPORT_SYMBOL_GPL(dasd_put_device_wake);

/*
 * Return dasd_device structure associated with cdev.
 * This function needs to be called with the ccw device
 * lock held. It can be used from interrupt context.
 */
struct dasd_device *
dasd_device_from_cdev_locked(struct ccw_device *cdev)
{
    struct dasd_device *device = dev_get_drvdata(&cdev->dev);

    if (!device)
        return ERR_PTR(-ENODEV);
    dasd_get_device(device);
    return device;
}

/*
 * Return dasd_device structure associated with cdev.
 */
struct dasd_device *
dasd_device_from_cdev(struct ccw_device *cdev)
{
    struct dasd_device *device;
    unsigned long flags;

    spin_lock_irqsave(get_ccwdev_lock(cdev), flags);
    device = dasd_device_from_cdev_locked(cdev);
    spin_unlock_irqrestore(get_ccwdev_lock(cdev), flags);
    return device;
}

void dasd_add_link_to_gendisk(struct gendisk *gdp, struct dasd_device *device)
{
    struct dasd_devmap *devmap;

    devmap = dasd_find_busid(dev_name(&device->cdev->dev));
    if (IS_ERR(devmap))
        return;
    spin_lock(&dasd_devmap_lock);
    gdp->private_data = devmap;
    spin_unlock(&dasd_devmap_lock);
}

struct dasd_device *dasd_device_from_gendisk(struct gendisk *gdp)
{
    struct dasd_device *device;
    struct dasd_devmap *devmap;

    if (!gdp->private_data)
        return NULL;
    device = NULL;
    spin_lock(&dasd_devmap_lock);
    devmap = gdp->private_data;
    if (devmap && devmap->device) {
        device = devmap->device;
        dasd_get_device(device);
    }
    spin_unlock(&dasd_devmap_lock);
    return device;
}

/*
 * SECTION: files in sysfs
 */

/*
 * failfast controls the behaviour, if no path is available
 */
static ssize_t dasd_ff_show(struct device *dev, struct device_attribute *attr,
                char *buf)
{
    struct dasd_devmap *devmap;
    int ff_flag;

    devmap = dasd_find_busid(dev_name(dev));
    if (!IS_ERR(devmap))
        ff_flag = (devmap->features & DASD_FEATURE_FAILFAST) != 0;
    else
        ff_flag = (DASD_FEATURE_DEFAULT & DASD_FEATURE_FAILFAST) != 0;
    return snprintf(buf, PAGE_SIZE, ff_flag ? "1\n" : "0\n");
}

static ssize_t dasd_ff_store(struct device *dev, struct device_attribute *attr,
          const char *buf, size_t count)
{
    struct dasd_devmap *devmap;
    int val;
    char *endp;

    devmap = dasd_devmap_from_cdev(to_ccwdev(dev));
    if (IS_ERR(devmap))
        return PTR_ERR(devmap);

    val = simple_strtoul(buf, &endp, 0);
    if (((endp + 1) < (buf + count)) || (val > 1))
        return -EINVAL;

    spin_lock(&dasd_devmap_lock);
    if (val)
        devmap->features |= DASD_FEATURE_FAILFAST;
    else
        devmap->features &= ~DASD_FEATURE_FAILFAST;
    if (devmap->device)
        devmap->device->features = devmap->features;
    spin_unlock(&dasd_devmap_lock);
    return count;
}

static DEVICE_ATTR(failfast, 0644, dasd_ff_show, dasd_ff_store);

/*
 * readonly controls the readonly status of a dasd
 */
static ssize_t
dasd_ro_show(struct device *dev, struct device_attribute *attr, char *buf)
{
    struct dasd_devmap *devmap;
    int ro_flag;

    devmap = dasd_find_busid(dev_name(dev));
    if (!IS_ERR(devmap))
        ro_flag = (devmap->features & DASD_FEATURE_READONLY) != 0;
    else
        ro_flag = (DASD_FEATURE_DEFAULT & DASD_FEATURE_READONLY) != 0;
    return snprintf(buf, PAGE_SIZE, ro_flag ? "1\n" : "0\n");
}

static ssize_t
dasd_ro_store(struct device *dev, struct device_attribute *attr,
          const char *buf, size_t count)
{
    struct dasd_devmap *devmap;
    struct dasd_device *device;
    int val;
    char *endp;

    devmap = dasd_devmap_from_cdev(to_ccwdev(dev));
    if (IS_ERR(devmap))
        return PTR_ERR(devmap);

    val = simple_strtoul(buf, &endp, 0);
    if (((endp + 1) < (buf + count)) || (val > 1))
        return -EINVAL;

    spin_lock(&dasd_devmap_lock);
    if (val)
        devmap->features |= DASD_FEATURE_READONLY;
    else
        devmap->features &= ~DASD_FEATURE_READONLY;
    device = devmap->device;
    if (device) {
        device->features = devmap->features;
        val = val || test_bit(DASD_FLAG_DEVICE_RO, &device->flags);
    }
    spin_unlock(&dasd_devmap_lock);
    if (device && device->block && device->block->gdp)
        set_disk_ro(device->block->gdp, val);
    return count;
}

static DEVICE_ATTR(readonly, 0644, dasd_ro_show, dasd_ro_store);
/*
 * erplog controls the logging of ERP related data
 * (e.g. failing channel programs).
 */
static ssize_t
dasd_erplog_show(struct device *dev, struct device_attribute *attr, char *buf)
{
    struct dasd_devmap *devmap;
    int erplog;

    devmap = dasd_find_busid(dev_name(dev));
    if (!IS_ERR(devmap))
        erplog = (devmap->features & DASD_FEATURE_ERPLOG) != 0;
    else
        erplog = (DASD_FEATURE_DEFAULT & DASD_FEATURE_ERPLOG) != 0;
    return snprintf(buf, PAGE_SIZE, erplog ? "1\n" : "0\n");
}

static ssize_t
dasd_erplog_store(struct device *dev, struct device_attribute *attr,
          const char *buf, size_t count)
{
    struct dasd_devmap *devmap;
    int val;
    char *endp;

    devmap = dasd_devmap_from_cdev(to_ccwdev(dev));
    if (IS_ERR(devmap))
        return PTR_ERR(devmap);

    val = simple_strtoul(buf, &endp, 0);
    if (((endp + 1) < (buf + count)) || (val > 1))
        return -EINVAL;

    spin_lock(&dasd_devmap_lock);
    if (val)
        devmap->features |= DASD_FEATURE_ERPLOG;
    else
        devmap->features &= ~DASD_FEATURE_ERPLOG;
    if (devmap->device)
        devmap->device->features = devmap->features;
    spin_unlock(&dasd_devmap_lock);
    return count;
}

static DEVICE_ATTR(erplog, 0644, dasd_erplog_show, dasd_erplog_store);

/*
 * use_diag controls whether the driver should use diag rather than ssch
 * to talk to the device
 */
static ssize_t
dasd_use_diag_show(struct device *dev, struct device_attribute *attr, char *buf)
{
    struct dasd_devmap *devmap;
    int use_diag;

    devmap = dasd_find_busid(dev_name(dev));
    if (!IS_ERR(devmap))
        use_diag = (devmap->features & DASD_FEATURE_USEDIAG) != 0;
    else
        use_diag = (DASD_FEATURE_DEFAULT & DASD_FEATURE_USEDIAG) != 0;
    return sprintf(buf, use_diag ? "1\n" : "0\n");
}

static ssize_t
dasd_use_diag_store(struct device *dev, struct device_attribute *attr,
            const char *buf, size_t count)
{
    struct dasd_devmap *devmap;
    ssize_t rc;
    int val;
    char *endp;

    devmap = dasd_devmap_from_cdev(to_ccwdev(dev));
    if (IS_ERR(devmap))
        return PTR_ERR(devmap);

    val = simple_strtoul(buf, &endp, 0);
    if (((endp + 1) < (buf + count)) || (val > 1))
        return -EINVAL;

    spin_lock(&dasd_devmap_lock);
    /* Changing diag discipline flag is only allowed in offline state. */
    rc = count;
    if (!devmap->device && !(devmap->features & DASD_FEATURE_USERAW)) {
        if (val)
            devmap->features |= DASD_FEATURE_USEDIAG;
        else
            devmap->features &= ~DASD_FEATURE_USEDIAG;
    } else
        rc = -EPERM;
    spin_unlock(&dasd_devmap_lock);
    return rc;
}

static DEVICE_ATTR(use_diag, 0644, dasd_use_diag_show, dasd_use_diag_store);

/*
 * use_raw controls whether the driver should give access to raw eckd data or
 * operate in standard mode
 */
static ssize_t
dasd_use_raw_show(struct device *dev, struct device_attribute *attr, char *buf)
{
    struct dasd_devmap *devmap;
    int use_raw;

    devmap = dasd_find_busid(dev_name(dev));
    if (!IS_ERR(devmap))
        use_raw = (devmap->features & DASD_FEATURE_USERAW) != 0;
    else
        use_raw = (DASD_FEATURE_DEFAULT & DASD_FEATURE_USERAW) != 0;
    return sprintf(buf, use_raw ? "1\n" : "0\n");
}

static ssize_t
dasd_use_raw_store(struct device *dev, struct device_attribute *attr,
            const char *buf, size_t count)
{
    struct dasd_devmap *devmap;
    ssize_t rc;
    unsigned long val;

    devmap = dasd_devmap_from_cdev(to_ccwdev(dev));
    if (IS_ERR(devmap))
        return PTR_ERR(devmap);

    if ((strict_strtoul(buf, 10, &val) != 0) || val > 1)
        return -EINVAL;

    spin_lock(&dasd_devmap_lock);
    /* Changing diag discipline flag is only allowed in offline state. */
    rc = count;
    if (!devmap->device && !(devmap->features & DASD_FEATURE_USEDIAG)) {
        if (val)
            devmap->features |= DASD_FEATURE_USERAW;
        else
            devmap->features &= ~DASD_FEATURE_USERAW;
    } else
        rc = -EPERM;
    spin_unlock(&dasd_devmap_lock);
    return rc;
}

static DEVICE_ATTR(raw_track_access, 0644, dasd_use_raw_show,
           dasd_use_raw_store);

static ssize_t
dasd_discipline_show(struct device *dev, struct device_attribute *attr,
             char *buf)
{
    struct dasd_device *device;
    ssize_t len;

    device = dasd_device_from_cdev(to_ccwdev(dev));
    if (IS_ERR(device))
        goto out;
    else if (!device->discipline) {
        dasd_put_device(device);
        goto out;
    } else {
        len = snprintf(buf, PAGE_SIZE, "%s\n",
                   device->discipline->name);
        dasd_put_device(device);
        return len;
    }
out:
    len = snprintf(buf, PAGE_SIZE, "none\n");
    return len;
}

static DEVICE_ATTR(discipline, 0444, dasd_discipline_show, NULL);

static ssize_t
dasd_device_status_show(struct device *dev, struct device_attribute *attr,
             char *buf)
{
    struct dasd_device *device;
    ssize_t len;

    device = dasd_device_from_cdev(to_ccwdev(dev));
    if (!IS_ERR(device)) {
        switch (device->state) {
        case DASD_STATE_NEW:
            len = snprintf(buf, PAGE_SIZE, "new\n");
            break;
        case DASD_STATE_KNOWN:
            len = snprintf(buf, PAGE_SIZE, "detected\n");
            break;
        case DASD_STATE_BASIC:
            len = snprintf(buf, PAGE_SIZE, "basic\n");
            break;
        case DASD_STATE_UNFMT:
            len = snprintf(buf, PAGE_SIZE, "unformatted\n");
            break;
        case DASD_STATE_READY:
            len = snprintf(buf, PAGE_SIZE, "ready\n");
            break;
        case DASD_STATE_ONLINE:
            len = snprintf(buf, PAGE_SIZE, "online\n");
            break;
        default:
            len = snprintf(buf, PAGE_SIZE, "no stat\n");
            break;
        }
        dasd_put_device(device);
    } else
        len = snprintf(buf, PAGE_SIZE, "unknown\n");
    return len;
}

static DEVICE_ATTR(status, 0444, dasd_device_status_show, NULL);

static ssize_t dasd_alias_show(struct device *dev,
                   struct device_attribute *attr, char *buf)
{
    struct dasd_device *device;
    struct dasd_uid uid;

    device = dasd_device_from_cdev(to_ccwdev(dev));
    if (IS_ERR(device))
        return sprintf(buf, "0\n");

    if (device->discipline && device->discipline->get_uid &&
        !device->discipline->get_uid(device, &uid)) {
        if (uid.type == UA_BASE_PAV_ALIAS ||
            uid.type == UA_HYPER_PAV_ALIAS) {
            dasd_put_device(device);
            return sprintf(buf, "1\n");
        }
    }
    dasd_put_device(device);

    return sprintf(buf, "0\n");
}

static DEVICE_ATTR(alias, 0444, dasd_alias_show, NULL);

static ssize_t dasd_vendor_show(struct device *dev,
                struct device_attribute *attr, char *buf)
{
    struct dasd_device *device;
    struct dasd_uid uid;
    char *vendor;

    device = dasd_device_from_cdev(to_ccwdev(dev));
    vendor = "";
    if (IS_ERR(device))
        return snprintf(buf, PAGE_SIZE, "%s\n", vendor);

    if (device->discipline && device->discipline->get_uid &&
        !device->discipline->get_uid(device, &uid))
            vendor = uid.vendor;

    dasd_put_device(device);

    return snprintf(buf, PAGE_SIZE, "%s\n", vendor);
}

static DEVICE_ATTR(vendor, 0444, dasd_vendor_show, NULL);

#define UID_STRLEN ( /* vendor */ 3 + 1 + /* serial    */ 14 + 1 +\
             /* SSID   */ 4 + 1 + /* unit addr */ 2 + 1 +\
             /* vduit */ 32 + 1)

static ssize_t
dasd_uid_show(struct device *dev, struct device_attribute *attr, char *buf)
{
    struct dasd_device *device;
    struct dasd_uid uid;
    char uid_string[UID_STRLEN];
    char ua_string[3];

    device = dasd_device_from_cdev(to_ccwdev(dev));
    uid_string[0] = 0;
    if (IS_ERR(device))
        return snprintf(buf, PAGE_SIZE, "%s\n", uid_string);

    if (device->discipline && device->discipline->get_uid &&
        !device->discipline->get_uid(device, &uid)) {
        switch (uid.type) {
        case UA_BASE_DEVICE:
            snprintf(ua_string, sizeof(ua_string), "%02x",
                 uid.real_unit_addr);
            break;
        case UA_BASE_PAV_ALIAS:
            snprintf(ua_string, sizeof(ua_string), "%02x",
                 uid.base_unit_addr);
            break;
        case UA_HYPER_PAV_ALIAS:
            snprintf(ua_string, sizeof(ua_string), "xx");
            break;
        default:
            /* should not happen, treat like base device */
            snprintf(ua_string, sizeof(ua_string), "%02x",
                 uid.real_unit_addr);
            break;
        }

        if (strlen(uid.vduit) > 0)
            snprintf(uid_string, sizeof(uid_string),
                 "%s.%s.%04x.%s.%s",
                 uid.vendor, uid.serial, uid.ssid, ua_string,
                 uid.vduit);
        else
            snprintf(uid_string, sizeof(uid_string),
                 "%s.%s.%04x.%s",
                 uid.vendor, uid.serial, uid.ssid, ua_string);
    }
    dasd_put_device(device);

    return snprintf(buf, PAGE_SIZE, "%s\n", uid_string);
}
static DEVICE_ATTR(uid, 0444, dasd_uid_show, NULL);

/*
 * extended error-reporting
 */
static ssize_t
dasd_eer_show(struct device *dev, struct device_attribute *attr, char *buf)
{
    struct dasd_devmap *devmap;
    int eer_flag;

    devmap = dasd_find_busid(dev_name(dev));
    if (!IS_ERR(devmap) && devmap->device)
        eer_flag = dasd_eer_enabled(devmap->device);
    else
        eer_flag = 0;
    return snprintf(buf, PAGE_SIZE, eer_flag ? "1\n" : "0\n");
}

static ssize_t
dasd_eer_store(struct device *dev, struct device_attribute *attr,
           const char *buf, size_t count)
{
    struct dasd_devmap *devmap;
    int val, rc;
    char *endp;

    devmap = dasd_devmap_from_cdev(to_ccwdev(dev));
    if (IS_ERR(devmap))
        return PTR_ERR(devmap);
    if (!devmap->device)
        return -ENODEV;

    val = simple_strtoul(buf, &endp, 0);
    if (((endp + 1) < (buf + count)) || (val > 1))
        return -EINVAL;

    if (val) {
        rc = dasd_eer_enable(devmap->device);
        if (rc)
            return rc;
    } else
        dasd_eer_disable(devmap->device);
    return count;
}

static DEVICE_ATTR(eer_enabled, 0644, dasd_eer_show, dasd_eer_store);

/*
 * expiration time for default requests
 */
static ssize_t
dasd_expires_show(struct device *dev, struct device_attribute *attr, char *buf)
{
    struct dasd_device *device;
    int len;

    device = dasd_device_from_cdev(to_ccwdev(dev));
    if (IS_ERR(device))
        return -ENODEV;
    len = snprintf(buf, PAGE_SIZE, "%lu\n", device->default_expires);
    dasd_put_device(device);
    return len;
}

static ssize_t
dasd_expires_store(struct device *dev, struct device_attribute *attr,
           const char *buf, size_t count)
{
    struct dasd_device *device;
    unsigned long val;

    device = dasd_device_from_cdev(to_ccwdev(dev));
    if (IS_ERR(device))
        return -ENODEV;

    if ((strict_strtoul(buf, 10, &val) != 0) ||
        (val > DASD_EXPIRES_MAX) || val == 0) {
        dasd_put_device(device);
        return -EINVAL;
    }

    if (val)
        device->default_expires = val;

    dasd_put_device(device);
    return count;
}

static DEVICE_ATTR(expires, 0644, dasd_expires_show, dasd_expires_store);

static ssize_t dasd_reservation_policy_show(struct device *dev,
                        struct device_attribute *attr,
                        char *buf)
{
    struct dasd_devmap *devmap;
    int rc = 0;

    devmap = dasd_find_busid(dev_name(dev));
    if (IS_ERR(devmap)) {
        rc = snprintf(buf, PAGE_SIZE, "ignore\n");
    } else {
        spin_lock(&dasd_devmap_lock);
        if (devmap->features & DASD_FEATURE_FAILONSLCK)
            rc = snprintf(buf, PAGE_SIZE, "fail\n");
        else
            rc = snprintf(buf, PAGE_SIZE, "ignore\n");
        spin_unlock(&dasd_devmap_lock);
    }
    return rc;
}

static ssize_t dasd_reservation_policy_store(struct device *dev,
                         struct device_attribute *attr,
                         const char *buf, size_t count)
{
    struct dasd_devmap *devmap;
    int rc;

    devmap = dasd_devmap_from_cdev(to_ccwdev(dev));
    if (IS_ERR(devmap))
        return PTR_ERR(devmap);
    rc = 0;
    spin_lock(&dasd_devmap_lock);
    if (sysfs_streq("ignore", buf))
        devmap->features &= ~DASD_FEATURE_FAILONSLCK;
    else if (sysfs_streq("fail", buf))
        devmap->features |= DASD_FEATURE_FAILONSLCK;
    else
        rc = -EINVAL;
    if (devmap->device)
        devmap->device->features = devmap->features;
    spin_unlock(&dasd_devmap_lock);
    if (rc)
        return rc;
    else
        return count;
}

static DEVICE_ATTR(reservation_policy, 0644,
           dasd_reservation_policy_show, dasd_reservation_policy_store);

static ssize_t dasd_reservation_state_show(struct device *dev,
                       struct device_attribute *attr,
                       char *buf)
{
    struct dasd_device *device;
    int rc = 0;

    device = dasd_device_from_cdev(to_ccwdev(dev));
    if (IS_ERR(device))
        return snprintf(buf, PAGE_SIZE, "none\n");

    if (test_bit(DASD_FLAG_IS_RESERVED, &device->flags))
        rc = snprintf(buf, PAGE_SIZE, "reserved\n");
    else if (test_bit(DASD_FLAG_LOCK_STOLEN, &device->flags))
        rc = snprintf(buf, PAGE_SIZE, "lost\n");
    else
        rc = snprintf(buf, PAGE_SIZE, "none\n");
    dasd_put_device(device);
    return rc;
}

static ssize_t dasd_reservation_state_store(struct device *dev,
                        struct device_attribute *attr,
                        const char *buf, size_t count)
{
    struct dasd_device *device;
    int rc = 0;

    device = dasd_device_from_cdev(to_ccwdev(dev));
    if (IS_ERR(device))
        return -ENODEV;
    if (sysfs_streq("reset", buf))
        clear_bit(DASD_FLAG_LOCK_STOLEN, &device->flags);
    else
        rc = -EINVAL;
    dasd_put_device(device);

    if (rc)
        return rc;
    else
        return count;
}

static DEVICE_ATTR(last_known_reservation_state, 0644,
           dasd_reservation_state_show, dasd_reservation_state_store);

static struct attribute * dasd_attrs[] = {
    &dev_attr_readonly.attr,
    &dev_attr_discipline.attr,
    &dev_attr_status.attr,
    &dev_attr_alias.attr,
    &dev_attr_vendor.attr,
    &dev_attr_uid.attr,
    &dev_attr_use_diag.attr,
    &dev_attr_raw_track_access.attr,
    &dev_attr_eer_enabled.attr,
    &dev_attr_erplog.attr,
    &dev_attr_failfast.attr,
    &dev_attr_expires.attr,
    &dev_attr_reservation_policy.attr,
    &dev_attr_last_known_reservation_state.attr,
    NULL,
};

static struct attribute_group dasd_attr_group = {
    .attrs = dasd_attrs,
};

/*
 * Return value of the specified feature.
 */
int
dasd_get_feature(struct ccw_device *cdev, int feature)
{
    struct dasd_devmap *devmap;

    devmap = dasd_find_busid(dev_name(&cdev->dev));
    if (IS_ERR(devmap))
        return PTR_ERR(devmap);

    return ((devmap->features & feature) != 0);
}

/*
 * Set / reset given feature.
 * Flag indicates wether to set (!=0) or the reset (=0) the feature.
 */
int
dasd_set_feature(struct ccw_device *cdev, int feature, int flag)
{
    struct dasd_devmap *devmap;

    devmap = dasd_find_busid(dev_name(&cdev->dev));
    if (IS_ERR(devmap))
        return PTR_ERR(devmap);

    spin_lock(&dasd_devmap_lock);
    if (flag)
        devmap->features |= feature;
    else
        devmap->features &= ~feature;
    if (devmap->device)
        devmap->device->features = devmap->features;
    spin_unlock(&dasd_devmap_lock);
    return 0;
}


int
dasd_add_sysfs_files(struct ccw_device *cdev)
{
    return sysfs_create_group(&cdev->dev.kobj, &dasd_attr_group);
}

void
dasd_remove_sysfs_files(struct ccw_device *cdev)
{
    sysfs_remove_group(&cdev->dev.kobj, &dasd_attr_group);
}


int
dasd_devmap_init(void)
{
    int i;

    /* Initialize devmap structures. */
    dasd_max_devindex = 0;
    for (i = 0; i < 256; i++)
        INIT_LIST_HEAD(&dasd_hashlists[i]);
    return 0;
}

void
dasd_devmap_exit(void)
{
    dasd_forget_ranges();
}