xref: /linux/drivers/s390/block/dasd_devmap.c (revision 55ab7e14222e5f0b0fd9f7711ca391d2924b35e3)

// SPDX-License-Identifier: GPL-2.0
/*
 * Author(s)......: Holger Smolinski <Holger.Smolinski@de.ibm.com>
 *		    Horst Hummel <Horst.Hummel@de.ibm.com>
 *		    Carsten Otte <Cotte@de.ibm.com>
 *		    Martin Schwidefsky <schwidefsky@de.ibm.com>
 * Bugreports.to..: <Linux390@de.ibm.com>
 * 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.
 *
 */

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

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

#define DASD_MAX_PARAMS 256

#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;
	struct dasd_copy_relation *copy;
	unsigned int aq_mask;
};

/*
 * 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[DASD_MAX_PARAMS];
module_param_array(dasd, charp, NULL, S_IRUGO);

/*
 * 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
static int __init dasd_call_setup(char *opt)
{
	static int i __initdata;
	char *tmp;

	while (i < DASD_MAX_PARAMS) {
		tmp = strsep(&opt, ",");
		if (!tmp)
			break;

		dasd[i++] = tmp;
	}

	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)
{
	unsigned int val;
	char *tok;

	/* 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;

		return 0;
	}

	/* Old style 0xXXXX or XXXX */
	if (!kstrtouint(str, 16, &val)) {
		*id0 = *id1 = 0;
		if (val > 0xffff)
			return -EINVAL;
		*devno = val;
		return 0;
	}

	/* New style x.y.z busid */
	tok = strsep(&str, ".");
	if (kstrtouint(tok, 16, &val) || val > 0xff)
		return -EINVAL;
	*id0 = val;

	tok = strsep(&str, ".");
	if (kstrtouint(tok, 16, &val) || val > 0xff)
		return -EINVAL;
	*id1 = val;

	tok = strsep(&str, ".");
	if (kstrtouint(tok, 16, &val) || val > 0xffff)
		return -EINVAL;
	*devno = val;

	return 0;
}

/*
 * Read colon separated list of dasd features.
 */
static int __init dasd_feature_list(char *str)
{
	int features, len, rc;

	features = 0;
	rc = 0;

	if (!str)
		return DASD_FEATURE_DEFAULT;

	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_warn("%.*s is not a supported device option\n",
				len, str);
			rc = -EINVAL;
		}
		str += len;
		if (*str != ':')
			break;
		str++;
	}

	return rc ? : 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 int __init dasd_parse_keyword(char *keyword)
{
	int length = strlen(keyword);

	if (strncmp("autodetect", keyword, length) == 0) {
		dasd_autodetect = 1;
		pr_info("The autodetection mode has been activated\n");
		return 0;
        }
	if (strncmp("probeonly", keyword, length) == 0) {
		dasd_probeonly = 1;
		pr_info("The probeonly mode has been activated\n");
		return 0;
        }
	if (strncmp("nopav", keyword, 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 0;
	}
	if (strncmp("nofcx", keyword, length) == 0) {
		dasd_nofcx = 1;
		pr_info("High Performance FICON support has been "
			"deactivated\n");
		return 0;
	}
	if (strncmp("fixedbuffers", keyword, length) == 0) {
		if (dasd_page_cache)
			return 0;
		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 0;
	}

	return -EINVAL;
}

/*
 * Split a string of a device range into its pieces and return the from, to, and
 * feature parts separately.
 * e.g.:
 * 0.0.1234-0.0.5678(ro:erplog) -> from: 0.0.1234 to: 0.0.5678 features: ro:erplog
 * 0.0.8765(raw) -> from: 0.0.8765 to: null features: raw
 * 0x4321 -> from: 0x4321 to: null features: null
 */
static int __init dasd_evaluate_range_param(char *range, char **from_str,
					    char **to_str, char **features_str)
{
	int rc = 0;

	/* Do we have a range or a single device? */
	if (strchr(range, '-')) {
		*from_str = strsep(&range, "-");
		*to_str = strsep(&range, "(");
		*features_str = strsep(&range, ")");
	} else {
		*from_str = strsep(&range, "(");
		*features_str = strsep(&range, ")");
	}

	if (*features_str && !range) {
		pr_warn("A closing parenthesis ')' is missing in the dasd= parameter\n");
		rc = -EINVAL;
	}

	return rc;
}

/*
 * Try to interprete the range string as a device number or a range of devices.
 * If the interpretation is successful, create the matching dasd_devmap entries.
 * If interpretation fails or in case of an error, return an error code.
 */
static int __init dasd_parse_range(const char *range)
{
	struct dasd_devmap *devmap;
	int from, from_id0, from_id1;
	int to, to_id0, to_id1;
	int features;
	char bus_id[DASD_BUS_ID_SIZE + 1];
	char *features_str = NULL;
	char *from_str = NULL;
	char *to_str = NULL;
	int rc = 0;
	char *tmp;

	tmp = kstrdup(range, GFP_KERNEL);
	if (!tmp)
		return -ENOMEM;

	if (dasd_evaluate_range_param(tmp, &from_str, &to_str, &features_str)) {
		rc = -EINVAL;
		goto out;
	}

	if (dasd_busid(from_str, &from_id0, &from_id1, &from)) {
		rc = -EINVAL;
		goto out;
	}

	to = from;
	to_id0 = from_id0;
	to_id1 = from_id1;
	if (to_str) {
		if (dasd_busid(to_str, &to_id0, &to_id1, &to)) {
			rc = -EINVAL;
			goto out;
		}
		if (from_id0 != to_id0 || from_id1 != to_id1 || from > to) {
			pr_err("%s is not a valid device range\n", range);
			rc = -EINVAL;
			goto out;
		}
	}

	features = dasd_feature_list(features_str);
	if (features < 0) {
		rc = -EINVAL;
		goto out;
	}
	/* each device in dasd= parameter should be set initially online */
	features |= DASD_FEATURE_INITIAL_ONLINE;
	while (from <= to) {
		scnprintf(bus_id, sizeof(bus_id),
			  "%01x.%01x.%04x", from_id0, from_id1, from++);
		devmap = dasd_add_busid(bus_id, features);
		if (IS_ERR(devmap)) {
			rc = PTR_ERR(devmap);
			goto out;
		}
	}

out:
	kfree(tmp);

	return rc;
}

/*
 * Parse parameters stored in dasd[]
 * The 'dasd=...' parameter allows to specify a comma separated list of
 * keywords and device ranges. The parameters in that list will be stored as
 * separate elementes in dasd[].
 */
int __init dasd_parse(void)
{
	int rc, i;
	char *cur;

	rc = 0;
	for (i = 0; i < DASD_MAX_PARAMS; i++) {
		cur = dasd[i];
		if (!cur)
			break;
		if (*cur == '\0')
			continue;

		rc = dasd_parse_keyword(cur);
		if (rc)
			rc = dasd_parse_range(cur);

		if (rc)
			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 = kzalloc_obj(struct dasd_devmap);
	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++;
		strscpy(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;
}

static struct dasd_devmap *
dasd_find_busid_locked(const char *bus_id)
{
	struct dasd_devmap *devmap, *tmp;
	int hash;

	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;
		}
	}
	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;

	spin_lock(&dasd_devmap_lock);
	devmap = dasd_find_busid_locked(bus_id);
	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);

	device->paths_info = kset_create_and_add("paths_info", NULL,
						 &device->cdev->dev.kobj);
	if (!device->paths_info)
		dev_warn(&cdev->dev, "Could not create paths_info kset\n");

	return device;
}

/*
 * allocate a PPRC data structure and call the discipline function to fill
 */
static int dasd_devmap_get_pprc_status(struct dasd_device *device,
				       struct dasd_pprc_data_sc4 **data)
{
	struct dasd_pprc_data_sc4 *temp;

	if (!device->discipline || !device->discipline->pprc_status) {
		dev_warn(&device->cdev->dev, "Unable to query copy relation status\n");
		return -EOPNOTSUPP;
	}
	temp = kzalloc_obj(*temp);
	if (!temp)
		return -ENOMEM;

	/* get PPRC information from storage */
	if (device->discipline->pprc_status(device, temp)) {
		dev_warn(&device->cdev->dev, "Error during copy relation status query\n");
		kfree(temp);
		return -EINVAL;
	}
	*data = temp;

	return 0;
}

/*
 * find an entry in a PPRC device_info array by a given UID
 * depending on the primary/secondary state of the device it has to be
 * matched with the respective fields
 */
static int dasd_devmap_entry_from_pprc_data(struct dasd_pprc_data_sc4 *data,
					    struct dasd_uid uid,
					    bool primary)
{
	int i;

	for (i = 0; i < DASD_CP_ENTRIES; i++) {
		if (primary) {
			if (data->dev_info[i].prim_cu_ssid == uid.ssid &&
			    data->dev_info[i].primary == uid.real_unit_addr)
				return i;
		} else {
			if (data->dev_info[i].sec_cu_ssid == uid.ssid &&
			    data->dev_info[i].secondary == uid.real_unit_addr)
				return i;
		}
	}
	return -1;
}

/*
 * check the consistency of a specified copy relation by checking
 * the following things:
 *
 *   - is the given device part of a copy pair setup
 *   - does the state of the device match the state in the PPRC status data
 *   - does the device UID match with the UID in the PPRC status data
 *   - to prevent misrouted IO check if the given device is present in all
 *     related PPRC status data
 */
static int dasd_devmap_check_copy_relation(struct dasd_device *device,
					   struct dasd_copy_entry *entry,
					   struct dasd_pprc_data_sc4 *data,
					   struct dasd_copy_relation *copy)
{
	struct dasd_pprc_data_sc4 *tmp_dat;
	struct dasd_device *tmp_dev;
	struct dasd_uid uid;
	int i, j;

	if (!device->discipline || !device->discipline->get_uid ||
	    device->discipline->get_uid(device, &uid))
		return 1;

	i = dasd_devmap_entry_from_pprc_data(data, uid, entry->primary);
	if (i < 0) {
		dev_warn(&device->cdev->dev, "Device not part of a copy relation\n");
		return 1;
	}

	/* double check which role the current device has */
	if (entry->primary) {
		if (data->dev_info[i].flags & 0x80) {
			dev_warn(&device->cdev->dev, "Copy pair secondary is setup as primary\n");
			return 1;
		}
		if (data->dev_info[i].prim_cu_ssid != uid.ssid ||
		    data->dev_info[i].primary != uid.real_unit_addr) {
			dev_warn(&device->cdev->dev,
				 "Primary device %s does not match copy pair status primary device %04x\n",
				 dev_name(&device->cdev->dev),
				 data->dev_info[i].prim_cu_ssid |
				 data->dev_info[i].primary);
			return 1;
		}
	} else {
		if (!(data->dev_info[i].flags & 0x80)) {
			dev_warn(&device->cdev->dev, "Copy pair primary is setup as secondary\n");
			return 1;
		}
		if (data->dev_info[i].sec_cu_ssid != uid.ssid ||
		    data->dev_info[i].secondary != uid.real_unit_addr) {
			dev_warn(&device->cdev->dev,
				 "Secondary device %s does not match copy pair status secondary device %04x\n",
				 dev_name(&device->cdev->dev),
				 data->dev_info[i].sec_cu_ssid |
				 data->dev_info[i].secondary);
			return 1;
		}
	}

	/*
	 * the current device has to be part of the copy relation of all
	 * entries to prevent misrouted IO to another copy pair
	 */
	for (j = 0; j < DASD_CP_ENTRIES; j++) {
		if (entry == &copy->entry[j])
			tmp_dev = device;
		else
			tmp_dev = copy->entry[j].device;

		if (!tmp_dev)
			continue;

		if (dasd_devmap_get_pprc_status(tmp_dev, &tmp_dat))
			return 1;

		if (dasd_devmap_entry_from_pprc_data(tmp_dat, uid, entry->primary) < 0) {
			dev_warn(&tmp_dev->cdev->dev,
				 "Copy pair relation does not contain device: %s\n",
				 dev_name(&device->cdev->dev));
			kfree(tmp_dat);
			return 1;
		}
		kfree(tmp_dat);
	}
	return 0;
}

/* delete device from copy relation entry */
static void dasd_devmap_delete_copy_relation_device(struct dasd_device *device)
{
	struct dasd_copy_relation *copy;
	int i;

	if (!device->copy)
		return;

	copy = device->copy;
	for (i = 0; i < DASD_CP_ENTRIES; i++) {
		if (copy->entry[i].device == device)
			copy->entry[i].device = NULL;
	}
	dasd_put_device(device);
	device->copy = NULL;
}

/*
 * read all required information for a copy relation setup and setup the device
 * accordingly
 */
int dasd_devmap_set_device_copy_relation(struct ccw_device *cdev,
					 bool pprc_enabled)
{
	struct dasd_pprc_data_sc4 *data = NULL;
	struct dasd_copy_entry *entry = NULL;
	struct dasd_copy_relation *copy;
	struct dasd_devmap *devmap;
	struct dasd_device *device;
	int i, rc = 0;

	devmap = dasd_devmap_from_cdev(cdev);
	if (IS_ERR(devmap))
		return PTR_ERR(devmap);

	device = devmap->device;
	if (!device)
		return -ENODEV;

	copy = devmap->copy;
	/* no copy pair setup for this device */
	if (!copy)
		goto out;

	rc = dasd_devmap_get_pprc_status(device, &data);
	if (rc)
		return rc;

	/* print error if PPRC is requested but not enabled on storage server */
	if (!pprc_enabled) {
		dev_err(&cdev->dev, "Copy relation not enabled on storage server\n");
		rc = -EINVAL;
		goto out;
	}

	if (!data->dev_info[0].state) {
		dev_warn(&device->cdev->dev, "Copy pair setup requested for device not in copy relation\n");
		rc = -EINVAL;
		goto out;
	}
	/* find entry */
	for (i = 0; i < DASD_CP_ENTRIES; i++) {
		if (copy->entry[i].configured &&
		    strncmp(dev_name(&cdev->dev),
			    copy->entry[i].busid, DASD_BUS_ID_SIZE) == 0) {
			entry = &copy->entry[i];
			break;
		}
	}
	if (!entry) {
		dev_warn(&device->cdev->dev, "Copy relation entry not found\n");
		rc = -EINVAL;
		goto out;
	}
	/* check if the copy relation is valid */
	if (dasd_devmap_check_copy_relation(device, entry, data, copy)) {
		dev_warn(&device->cdev->dev, "Copy relation faulty\n");
		rc = -EINVAL;
		goto out;
	}

	dasd_get_device(device);
	copy->entry[i].device = device;
	device->copy = copy;
out:
	kfree(data);
	return rc;
}
EXPORT_SYMBOL_GPL(dasd_devmap_set_device_copy_relation);

/*
 * 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);

	/* Remove copy relation */
	dasd_devmap_delete_copy_relation_device(device);
	/*
	 * 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);

	dasd_generic_free_discipline(device);

	kset_unregister(device->paths_info);

	/* 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);
}
EXPORT_SYMBOL(dasd_add_link_to_gendisk);

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 sysfs_emit(buf, 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)
{
	unsigned int val;
	int rc;

	if (kstrtouint(buf, 0, &val) || val > 1)
		return -EINVAL;

	rc = dasd_set_feature(to_ccwdev(dev), DASD_FEATURE_FAILFAST, val);

	return rc ? : 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;
	struct dasd_device *device;
	int ro_flag = 0;

	devmap = dasd_find_busid(dev_name(dev));
	if (IS_ERR(devmap))
		goto out;

	ro_flag = !!(devmap->features & DASD_FEATURE_READONLY);

	spin_lock(&dasd_devmap_lock);
	device = devmap->device;
	if (device)
		ro_flag |= test_bit(DASD_FLAG_DEVICE_RO, &device->flags);
	spin_unlock(&dasd_devmap_lock);

out:
	return sysfs_emit(buf, 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 ccw_device *cdev = to_ccwdev(dev);
	struct dasd_device *device;
	unsigned long flags;
	unsigned int val;
	int rc;

	if (kstrtouint(buf, 0, &val) || val > 1)
		return -EINVAL;

	rc = dasd_set_feature(cdev, DASD_FEATURE_READONLY, val);
	if (rc)
		return rc;

	device = dasd_device_from_cdev(cdev);
	if (IS_ERR(device))
		return count;

	spin_lock_irqsave(get_ccwdev_lock(cdev), flags);
	val = val || test_bit(DASD_FLAG_DEVICE_RO, &device->flags);

	if (!device->block || !device->block->gdp ||
	    test_bit(DASD_FLAG_OFFLINE, &device->flags)) {
		spin_unlock_irqrestore(get_ccwdev_lock(cdev), flags);
		goto out;
	}
	/* Increase open_count to avoid losing the block device */
	atomic_inc(&device->block->open_count);
	spin_unlock_irqrestore(get_ccwdev_lock(cdev), flags);

	set_disk_ro(device->block->gdp, val);
	atomic_dec(&device->block->open_count);

out:
	dasd_put_device(device);

	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 sysfs_emit(buf, erplog ? "1\n" : "0\n");
}

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

	if (kstrtouint(buf, 0, &val) || val > 1)
		return -EINVAL;

	rc = dasd_set_feature(to_ccwdev(dev), DASD_FEATURE_ERPLOG, val);

	return rc ? : 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 sysfs_emit(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;
	unsigned int val;
	ssize_t rc;

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

	if (kstrtouint(buf, 0, &val) || 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 sysfs_emit(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 ((kstrtoul(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_safe_offline_store(struct device *dev, struct device_attribute *attr,
			const char *buf, size_t count)
{
	struct ccw_device *cdev = to_ccwdev(dev);
	struct dasd_device *device;
	unsigned long flags;
	int rc;

	spin_lock_irqsave(get_ccwdev_lock(cdev), flags);
	device = dasd_device_from_cdev_locked(cdev);
	if (IS_ERR(device)) {
		rc = PTR_ERR(device);
		spin_unlock_irqrestore(get_ccwdev_lock(cdev), flags);
		goto out;
	}

	if (test_bit(DASD_FLAG_OFFLINE, &device->flags) ||
	    test_bit(DASD_FLAG_SAFE_OFFLINE_RUNNING, &device->flags)) {
		/* Already doing offline processing */
		dasd_put_device(device);
		spin_unlock_irqrestore(get_ccwdev_lock(cdev), flags);
		rc = -EBUSY;
		goto out;
	}

	set_bit(DASD_FLAG_SAFE_OFFLINE, &device->flags);
	dasd_put_device(device);
	spin_unlock_irqrestore(get_ccwdev_lock(cdev), flags);

	rc = ccw_device_set_offline(cdev);

out:
	return rc ? rc : count;
}

static DEVICE_ATTR(safe_offline, 0200, NULL, dasd_safe_offline_store);

static ssize_t
dasd_access_show(struct device *dev, struct device_attribute *attr,
		 char *buf)
{
	struct ccw_device *cdev = to_ccwdev(dev);
	struct dasd_device *device;
	int count;

	device = dasd_device_from_cdev(cdev);
	if (IS_ERR(device))
		return PTR_ERR(device);

	if (!device->discipline)
		count = -ENODEV;
	else if (!device->discipline->host_access_count)
		count = -EOPNOTSUPP;
	else
		count = device->discipline->host_access_count(device);

	dasd_put_device(device);
	if (count < 0)
		return count;

	return sysfs_emit(buf, "%d\n", count);
}

static DEVICE_ATTR(host_access_count, 0444, dasd_access_show, NULL);

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 = sysfs_emit(buf, "%s\n",
				 device->discipline->name);
		dasd_put_device(device);
		return len;
	}
out:
	len = sysfs_emit(buf, "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 = sysfs_emit(buf, "new\n");
			break;
		case DASD_STATE_KNOWN:
			len = sysfs_emit(buf, "detected\n");
			break;
		case DASD_STATE_BASIC:
			len = sysfs_emit(buf, "basic\n");
			break;
		case DASD_STATE_UNFMT:
			len = sysfs_emit(buf, "unformatted\n");
			break;
		case DASD_STATE_READY:
			len = sysfs_emit(buf, "ready\n");
			break;
		case DASD_STATE_ONLINE:
			len = sysfs_emit(buf, "online\n");
			break;
		default:
			len = sysfs_emit(buf, "no stat\n");
			break;
		}
		dasd_put_device(device);
	} else
		len = sysfs_emit(buf, "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 sysfs_emit(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 sysfs_emit(buf, "1\n");
		}
	}
	dasd_put_device(device);

	return sysfs_emit(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 sysfs_emit(buf, "%s\n", vendor);

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

	dasd_put_device(device);

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

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

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

	device = dasd_device_from_cdev(to_ccwdev(dev));
	uid_string[0] = 0;
	if (IS_ERR(device))
		return sysfs_emit(buf, "%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;
		}

		snprintf(uid_string, sizeof(uid_string), "%s.%s.%04x.%s%s%s",
			 uid.vendor, uid.serial, uid.ssid, ua_string,
			 uid.vduit[0] ? "." : "", uid.vduit);
	}
	dasd_put_device(device);

	return sysfs_emit(buf, "%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 sysfs_emit(buf, 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_device *device;
	unsigned int val;
	int rc = 0;

	device = dasd_device_from_cdev(to_ccwdev(dev));
	if (IS_ERR(device))
		return PTR_ERR(device);

	if (kstrtouint(buf, 0, &val) || val > 1)
		return -EINVAL;

	if (val)
		rc = dasd_eer_enable(device);
	else
		dasd_eer_disable(device);

	dasd_put_device(device);

	return rc ? : count;
}

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

/*
 * aq_mask controls if the DASD should be quiesced on certain triggers
 * The aq_mask attribute is interpreted as bitmap of the DASD_EER_* triggers.
 */
static ssize_t dasd_aq_mask_show(struct device *dev, struct device_attribute *attr,
				 char *buf)
{
	struct dasd_devmap *devmap;
	unsigned int aq_mask = 0;

	devmap = dasd_find_busid(dev_name(dev));
	if (!IS_ERR(devmap))
		aq_mask = devmap->aq_mask;

	return sysfs_emit(buf, "%d\n", aq_mask);
}

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

	if (kstrtouint(buf, 0, &val) || val > DASD_EER_VALID)
		return -EINVAL;

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

	spin_lock(&dasd_devmap_lock);
	devmap->aq_mask = val;
	if (devmap->device)
		devmap->device->aq_mask = devmap->aq_mask;
	spin_unlock(&dasd_devmap_lock);

	return count;
}

static DEVICE_ATTR(aq_mask, 0644, dasd_aq_mask_show, dasd_aq_mask_store);

/*
 * aq_requeue controls if requests are returned to the blocklayer on quiesce
 * or if requests are only not started
 */
static ssize_t dasd_aqr_show(struct device *dev, struct device_attribute *attr,
			     char *buf)
{
	struct dasd_devmap *devmap;
	int flag;

	devmap = dasd_find_busid(dev_name(dev));
	if (!IS_ERR(devmap))
		flag = (devmap->features & DASD_FEATURE_REQUEUEQUIESCE) != 0;
	else
		flag = (DASD_FEATURE_DEFAULT &
			DASD_FEATURE_REQUEUEQUIESCE) != 0;
	return sysfs_emit(buf, "%d\n", flag);
}

static ssize_t dasd_aqr_store(struct device *dev, struct device_attribute *attr,
			      const char *buf, size_t count)
{
	bool val;
	int rc;

	if (kstrtobool(buf, &val))
		return -EINVAL;

	rc = dasd_set_feature(to_ccwdev(dev), DASD_FEATURE_REQUEUEQUIESCE, val);

	return rc ? : count;
}

static DEVICE_ATTR(aq_requeue, 0644, dasd_aqr_show, dasd_aqr_store);

/*
 * aq_timeouts controls how much retries have to time out until
 * a device gets autoquiesced
 */
static ssize_t
dasd_aq_timeouts_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 = sysfs_emit(buf, "%u\n", device->aq_timeouts);
	dasd_put_device(device);
	return len;
}

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

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

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

	if (val)
		device->aq_timeouts = val;

	dasd_put_device(device);
	return count;
}

static DEVICE_ATTR(aq_timeouts, 0644, dasd_aq_timeouts_show,
		   dasd_aq_timeouts_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 = sysfs_emit(buf, "%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 ((kstrtoul(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);

/* ESE fulltrack write aggressiveness knob (0..100, see DASD_FT_BIAS_*) */
static ssize_t
full_track_bias_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 = sysfs_emit(buf, "%u\n", device->ft_bias);
	dasd_put_device(device);
	return len;
}

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

	if (kstrtouint(buf, 0, &val) || val > DASD_FT_BIAS_MAX)
		return -EINVAL;

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

	/*
	 * ft_bias is the tuning target; fulltrack is a best-effort mode hint
	 * that the per-IO heuristic also updates locklessly. A racing writer can
	 * at most leave a transient mismatch that self-corrects on the next IO,
	 * never corruption, so the update is left unlocked.
	 */
	device->ft_bias = val;
	dasd_ft_bias_apply(device);

	dasd_put_device(device);
	return count;
}

static DEVICE_ATTR_RW(full_track_bias);

static const char * const dasd_ese_heu_state_names[] = {
	[DASD_ESE_HEU_FT1_ACTIVE] = "fulltrack active",
	[DASD_ESE_HEU_PROBING]    = "probing",
	[DASD_ESE_HEU_FT0_STABLE] = "fulltrack inactive",
};

/* read-only: current full-track mode / adaptive FSM state, for observability */
static ssize_t
ese_heuristic_state_show(struct device *dev, struct device_attribute *attr,
			 char *buf)
{
	struct dasd_device *device;
	unsigned int state;
	int len;

	device = dasd_device_from_cdev(to_ccwdev(dev));
	if (IS_ERR(device))
		return -ENODEV;
	if (device->ft_bias == 0) {
		len = sysfs_emit(buf, "fulltrack deactivated\n");
	} else if (device->ft_bias >= DASD_FT_BIAS_MAX) {
		len = sysfs_emit(buf, "fulltrack permanent active\n");
	} else if (!dasd_ese_adaptive(device)) {
		/* adaptive range but not ESE: the heuristic does not run */
		len = sysfs_emit(buf, "fulltrack deactivated\n");
	} else {
		state = device->ese_probe_state;
		if (state < ARRAY_SIZE(dasd_ese_heu_state_names))
			len = sysfs_emit(buf, "%s\n", dasd_ese_heu_state_names[state]);
		else
			len = sysfs_emit(buf, "unknown\n");
	}
	dasd_put_device(device);
	return len;
}

static DEVICE_ATTR_RO(ese_heuristic_state);

static ssize_t
dasd_retries_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 = sysfs_emit(buf, "%lu\n", device->default_retries);
	dasd_put_device(device);
	return len;
}

static ssize_t
dasd_retries_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 ((kstrtoul(buf, 10, &val) != 0) ||
	    (val > DASD_RETRIES_MAX)) {
		dasd_put_device(device);
		return -EINVAL;
	}

	if (val)
		device->default_retries = val;

	dasd_put_device(device);
	return count;
}

static DEVICE_ATTR(retries, 0644, dasd_retries_show, dasd_retries_store);

static ssize_t
dasd_timeout_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 = sysfs_emit(buf, "%lu\n", device->blk_timeout);
	dasd_put_device(device);
	return len;
}

static ssize_t
dasd_timeout_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) || !device->block)
		return -ENODEV;

	if ((kstrtoul(buf, 10, &val) != 0) ||
	    val > UINT_MAX / HZ) {
		dasd_put_device(device);
		return -EINVAL;
	}
	if (!device->block->gdp) {
		dasd_put_device(device);
		return -ENODEV;
	}

	device->blk_timeout = val;
	blk_queue_rq_timeout(device->block->gdp->queue, val * HZ);

	dasd_put_device(device);
	return count;
}

static DEVICE_ATTR(timeout, 0644,
		   dasd_timeout_show, dasd_timeout_store);


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

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

	if ((kstrtouint(buf, 16, &val) != 0) || val > 0xff)
		val = 0;

	if (device->discipline && device->discipline->reset_path)
		device->discipline->reset_path(device, (__u8) val);

	dasd_put_device(device);
	return count;
}

static DEVICE_ATTR(path_reset, 0200, NULL, dasd_path_reset_store);

static ssize_t dasd_hpf_show(struct device *dev, struct device_attribute *attr,
			     char *buf)
{
	struct dasd_device *device;
	int hpf;

	device = dasd_device_from_cdev(to_ccwdev(dev));
	if (IS_ERR(device))
		return -ENODEV;
	if (!device->discipline || !device->discipline->hpf_enabled) {
		dasd_put_device(device);
		return sysfs_emit(buf, "%d\n", dasd_nofcx);
	}
	hpf = device->discipline->hpf_enabled(device);
	dasd_put_device(device);
	return sysfs_emit(buf, "%d\n", hpf);
}

static DEVICE_ATTR(hpf, 0444, dasd_hpf_show, NULL);

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 = sysfs_emit(buf, "ignore\n");
	} else {
		spin_lock(&dasd_devmap_lock);
		if (devmap->features & DASD_FEATURE_FAILONSLCK)
			rc = sysfs_emit(buf, "fail\n");
		else
			rc = sysfs_emit(buf, "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 ccw_device *cdev = to_ccwdev(dev);
	int rc;

	if (sysfs_streq("ignore", buf))
		rc = dasd_set_feature(cdev, DASD_FEATURE_FAILONSLCK, 0);
	else if (sysfs_streq("fail", buf))
		rc = dasd_set_feature(cdev, DASD_FEATURE_FAILONSLCK, 1);
	else
		rc = -EINVAL;

	return rc ? : 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 sysfs_emit(buf, "none\n");

	if (test_bit(DASD_FLAG_IS_RESERVED, &device->flags))
		rc = sysfs_emit(buf, "reserved\n");
	else if (test_bit(DASD_FLAG_LOCK_STOLEN, &device->flags))
		rc = sysfs_emit(buf, "lost\n");
	else
		rc = sysfs_emit(buf, "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 ssize_t dasd_pm_show(struct device *dev,
			      struct device_attribute *attr, char *buf)
{
	struct dasd_device *device;
	u8 opm, nppm, cablepm, cuirpm, hpfpm, ifccpm;

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

	opm = dasd_path_get_opm(device);
	nppm = dasd_path_get_nppm(device);
	cablepm = dasd_path_get_cablepm(device);
	cuirpm = dasd_path_get_cuirpm(device);
	hpfpm = dasd_path_get_hpfpm(device);
	ifccpm = dasd_path_get_ifccpm(device);
	dasd_put_device(device);

	return sysfs_emit(buf, "%02x %02x %02x %02x %02x %02x\n", opm, nppm,
			  cablepm, cuirpm, hpfpm, ifccpm);
}

static DEVICE_ATTR(path_masks, 0444, dasd_pm_show, NULL);

/*
 * threshold value for IFCC/CCC errors
 */
static ssize_t
dasd_path_threshold_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 = sysfs_emit(buf, "%lu\n", device->path_thrhld);
	dasd_put_device(device);
	return len;
}

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

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

	if (kstrtoul(buf, 10, &val) != 0 || val > DASD_THRHLD_MAX) {
		dasd_put_device(device);
		return -EINVAL;
	}
	spin_lock_irqsave(get_ccwdev_lock(to_ccwdev(dev)), flags);
	device->path_thrhld = val;
	spin_unlock_irqrestore(get_ccwdev_lock(to_ccwdev(dev)), flags);
	dasd_put_device(device);
	return count;
}
static DEVICE_ATTR(path_threshold, 0644, dasd_path_threshold_show,
		   dasd_path_threshold_store);

/*
 * configure if path is disabled after IFCC/CCC error threshold is
 * exceeded
 */
static ssize_t
dasd_path_autodisable_show(struct device *dev,
				   struct device_attribute *attr, char *buf)
{
	struct dasd_devmap *devmap;
	int flag;

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

static ssize_t
dasd_path_autodisable_store(struct device *dev,
				    struct device_attribute *attr,
				    const char *buf, size_t count)
{
	unsigned int val;
	int rc;

	if (kstrtouint(buf, 0, &val) || val > 1)
		return -EINVAL;

	rc = dasd_set_feature(to_ccwdev(dev),
			      DASD_FEATURE_PATH_AUTODISABLE, val);

	return rc ? : count;
}

static DEVICE_ATTR(path_autodisable, 0644,
		   dasd_path_autodisable_show,
		   dasd_path_autodisable_store);
/*
 * interval for IFCC/CCC checks
 * meaning time with no IFCC/CCC error before the error counter
 * gets reset
 */
static ssize_t
dasd_path_interval_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 = sysfs_emit(buf, "%lu\n", device->path_interval);
	dasd_put_device(device);
	return len;
}

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

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

	if ((kstrtoul(buf, 10, &val) != 0) ||
	    (val > DASD_INTERVAL_MAX) || val == 0) {
		dasd_put_device(device);
		return -EINVAL;
	}
	spin_lock_irqsave(get_ccwdev_lock(to_ccwdev(dev)), flags);
	if (val)
		device->path_interval = val;
	spin_unlock_irqrestore(get_ccwdev_lock(to_ccwdev(dev)), flags);
	dasd_put_device(device);
	return count;
}

static DEVICE_ATTR(path_interval, 0644, dasd_path_interval_show,
		   dasd_path_interval_store);

static ssize_t
dasd_device_fcs_show(struct device *dev, struct device_attribute *attr,
		     char *buf)
{
	struct dasd_device *device;
	int fc_sec;
	int rc;

	device = dasd_device_from_cdev(to_ccwdev(dev));
	if (IS_ERR(device))
		return -ENODEV;
	fc_sec = dasd_path_get_fcs_device(device);
	if (fc_sec == -EINVAL)
		rc = sysfs_emit(buf, "Inconsistent\n");
	else
		rc = sysfs_emit(buf, "%s\n", dasd_path_get_fcs_str(fc_sec));
	dasd_put_device(device);

	return rc;
}
static DEVICE_ATTR(fc_security, 0444, dasd_device_fcs_show, NULL);

static ssize_t
dasd_path_fcs_show(struct kobject *kobj, struct kobj_attribute *attr, char *buf)
{
	struct dasd_path *path = to_dasd_path(kobj);
	unsigned int fc_sec = path->fc_security;

	return sysfs_emit(buf, "%s\n", dasd_path_get_fcs_str(fc_sec));
}

static struct kobj_attribute path_fcs_attribute =
	__ATTR(fc_security, 0444, dasd_path_fcs_show, NULL);

/*
 * print copy relation in the form
 * primary,secondary[1] primary,secondary[2], ...
 */
static ssize_t
dasd_copy_pair_show(struct device *dev,
		    struct device_attribute *attr, char *buf)
{
	char prim_busid[DASD_BUS_ID_SIZE];
	struct dasd_copy_relation *copy;
	struct dasd_devmap *devmap;
	int len = 0;
	int i;

	devmap = dasd_find_busid(dev_name(dev));
	if (IS_ERR(devmap))
		return -ENODEV;

	if (!devmap->copy)
		return -ENODEV;

	copy = devmap->copy;
	/* find primary */
	for (i = 0; i < DASD_CP_ENTRIES; i++) {
		if (copy->entry[i].configured && copy->entry[i].primary) {
			strscpy(prim_busid, copy->entry[i].busid,
				DASD_BUS_ID_SIZE);
			break;
		}
	}
	if (i == DASD_CP_ENTRIES)
		goto out;

	/* print all secondary */
	for (i = 0; i < DASD_CP_ENTRIES; i++) {
		if (copy->entry[i].configured && !copy->entry[i].primary)
			len += sysfs_emit_at(buf, len, "%s,%s ", prim_busid,
					     copy->entry[i].busid);
	}

	len += sysfs_emit_at(buf, len, "\n");
out:
	return len;
}

static int dasd_devmap_set_copy_relation(struct dasd_devmap *devmap,
					 struct dasd_copy_relation *copy,
					 char *busid, bool primary)
{
	int i;

	/* find free entry */
	for (i = 0; i < DASD_CP_ENTRIES; i++) {
		/* current bus_id already included, nothing to do */
		if (copy->entry[i].configured &&
		    strncmp(copy->entry[i].busid, busid, DASD_BUS_ID_SIZE) == 0)
			return 0;

		if (!copy->entry[i].configured)
			break;
	}
	if (i == DASD_CP_ENTRIES)
		return -EINVAL;

	copy->entry[i].configured = true;
	strscpy(copy->entry[i].busid, busid, DASD_BUS_ID_SIZE);
	if (primary) {
		copy->active = &copy->entry[i];
		copy->entry[i].primary = true;
	}
	if (!devmap->copy)
		devmap->copy = copy;

	return 0;
}

static void dasd_devmap_del_copy_relation(struct dasd_copy_relation *copy,
					  char *busid)
{
	int i;

	spin_lock(&dasd_devmap_lock);
	/* find entry */
	for (i = 0; i < DASD_CP_ENTRIES; i++) {
		if (copy->entry[i].configured &&
		    strncmp(copy->entry[i].busid, busid, DASD_BUS_ID_SIZE) == 0)
			break;
	}
	if (i == DASD_CP_ENTRIES || !copy->entry[i].configured) {
		spin_unlock(&dasd_devmap_lock);
		return;
	}

	copy->entry[i].configured = false;
	memset(copy->entry[i].busid, 0, DASD_BUS_ID_SIZE);
	if (copy->active == &copy->entry[i]) {
		copy->active = NULL;
		copy->entry[i].primary = false;
	}
	spin_unlock(&dasd_devmap_lock);
}

static int dasd_devmap_clear_copy_relation(struct device *dev)
{
	struct dasd_copy_relation *copy;
	struct dasd_devmap *devmap;
	int i, rc = 1;

	devmap = dasd_devmap_from_cdev(to_ccwdev(dev));
	if (IS_ERR(devmap))
		return 1;

	spin_lock(&dasd_devmap_lock);
	if (!devmap->copy)
		goto out;

	copy = devmap->copy;
	/* first check if all secondary devices are offline*/
	for (i = 0; i < DASD_CP_ENTRIES; i++) {
		if (!copy->entry[i].configured)
			continue;

		if (copy->entry[i].device == copy->active->device)
			continue;

		if (copy->entry[i].device)
			goto out;
	}
	/* clear all devmap entries */
	for (i = 0; i < DASD_CP_ENTRIES; i++) {
		if (strlen(copy->entry[i].busid) == 0)
			continue;
		if (copy->entry[i].device) {
			dasd_put_device(copy->entry[i].device);
			copy->entry[i].device->copy = NULL;
			copy->entry[i].device = NULL;
		}
		devmap = dasd_find_busid_locked(copy->entry[i].busid);
		devmap->copy = NULL;
		memset(copy->entry[i].busid, 0, DASD_BUS_ID_SIZE);
	}
	kfree(copy);
	rc = 0;
out:
	spin_unlock(&dasd_devmap_lock);
	return rc;
}

/*
 * parse BUSIDs from a copy pair
 */
static int dasd_devmap_parse_busid(const char *buf, char *prim_busid,
				   char *sec_busid)
{
	char *primary, *secondary, *tmp, *pt;
	int id0, id1, id2;

	pt =  kstrdup(buf, GFP_KERNEL);
	tmp = pt;
	if (!tmp)
		return -ENOMEM;

	primary = strsep(&tmp, ",");
	if (!primary) {
		kfree(pt);
		return -EINVAL;
	}
	secondary = strsep(&tmp, ",");
	if (!secondary) {
		kfree(pt);
		return -EINVAL;
	}
	if (dasd_busid(primary, &id0, &id1, &id2)) {
		kfree(pt);
		return -EINVAL;
	}
	sprintf(prim_busid, "%01x.%01x.%04x", id0, id1, id2);
	if (dasd_busid(secondary, &id0, &id1, &id2)) {
		kfree(pt);
		return -EINVAL;
	}
	sprintf(sec_busid, "%01x.%01x.%04x", id0, id1, id2);
	kfree(pt);

	return 0;
}

static ssize_t dasd_copy_pair_store(struct device *dev,
				    struct device_attribute *attr,
				    const char *buf, size_t count)
{
	struct dasd_devmap *prim_devmap, *sec_devmap;
	char prim_busid[DASD_BUS_ID_SIZE];
	char sec_busid[DASD_BUS_ID_SIZE];
	struct dasd_copy_relation *copy;
	struct dasd_device *device;
	bool pprc_enabled;
	int rc;

	if (strncmp(buf, "clear", strlen("clear")) == 0) {
		if (dasd_devmap_clear_copy_relation(dev))
			return -EINVAL;
		return count;
	}

	rc = dasd_devmap_parse_busid(buf, prim_busid, sec_busid);
	if (rc)
		return rc;

	if (strncmp(dev_name(dev), prim_busid, DASD_BUS_ID_SIZE) != 0 &&
	    strncmp(dev_name(dev), sec_busid, DASD_BUS_ID_SIZE) != 0)
		return -EINVAL;

	/* allocate primary devmap if needed */
	prim_devmap = dasd_find_busid(prim_busid);
	if (IS_ERR(prim_devmap)) {
		prim_devmap = dasd_add_busid(prim_busid, DASD_FEATURE_DEFAULT);
		if (IS_ERR(prim_devmap))
			return PTR_ERR(prim_devmap);
	}

	/* allocate secondary devmap if needed */
	sec_devmap = dasd_find_busid(sec_busid);
	if (IS_ERR(sec_devmap)) {
		sec_devmap = dasd_add_busid(sec_busid, DASD_FEATURE_DEFAULT);
		if (IS_ERR(sec_devmap))
			return PTR_ERR(sec_devmap);
	}

	/* setting copy relation is only allowed for offline secondary */
	if (sec_devmap->device)
		return -EINVAL;

	if (prim_devmap->copy) {
		copy = prim_devmap->copy;
	} else if (sec_devmap->copy) {
		copy = sec_devmap->copy;
	} else {
		copy = kzalloc_obj(*copy);
		if (!copy)
			return -ENOMEM;
	}
	spin_lock(&dasd_devmap_lock);
	rc = dasd_devmap_set_copy_relation(prim_devmap, copy, prim_busid, true);
	if (rc) {
		spin_unlock(&dasd_devmap_lock);
		return rc;
	}
	rc = dasd_devmap_set_copy_relation(sec_devmap, copy, sec_busid, false);
	if (rc) {
		spin_unlock(&dasd_devmap_lock);
		return rc;
	}
	spin_unlock(&dasd_devmap_lock);

	/* if primary device is already online call device setup directly */
	if (prim_devmap->device && !prim_devmap->device->copy) {
		device = prim_devmap->device;
		if (device->discipline->pprc_enabled) {
			pprc_enabled = device->discipline->pprc_enabled(device);
			rc = dasd_devmap_set_device_copy_relation(device->cdev,
								  pprc_enabled);
		} else {
			rc = -EOPNOTSUPP;
		}
	}
	if (rc) {
		dasd_devmap_del_copy_relation(copy, prim_busid);
		dasd_devmap_del_copy_relation(copy, sec_busid);
		count = rc;
	}

	return count;
}
static DEVICE_ATTR(copy_pair, 0644, dasd_copy_pair_show,
		   dasd_copy_pair_store);

static ssize_t
dasd_copy_role_show(struct device *dev,
		    struct device_attribute *attr, char *buf)
{
	struct dasd_copy_relation *copy;
	struct dasd_device *device;
	int len, i;

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

	if (!device->copy) {
		len = sysfs_emit(buf, "none\n");
		goto out;
	}
	copy = device->copy;
	/* only the active device is primary */
	if (copy->active->device == device) {
		len = sysfs_emit(buf, "primary\n");
		goto out;
	}
	for (i = 0; i < DASD_CP_ENTRIES; i++) {
		if (copy->entry[i].device == device) {
			len = sysfs_emit(buf, "secondary\n");
			goto out;
		}
	}
	/* not in the list, no COPY role */
	len = sysfs_emit(buf, "none\n");
out:
	dasd_put_device(device);
	return len;
}
static DEVICE_ATTR(copy_role, 0444, dasd_copy_role_show, NULL);

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

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

	/*
	 * do not try during offline processing
	 * early check only
	 * the sleep_on function itself checks for offline
	 * processing again
	 */
	if (test_bit(DASD_FLAG_OFFLINE, &device->flags)) {
		rc = -EBUSY;
		goto out;
	}
	if (!device->discipline || !device->discipline->device_ping) {
		rc = -EOPNOTSUPP;
		goto out;
	}
	rc = device->discipline->device_ping(device);
	if (!rc)
		rc = count;
out:
	dasd_put_device(device);
	return rc;
}
static DEVICE_ATTR(ping, 0200, NULL, dasd_device_ping);

#define DASD_DEFINE_ATTR(_name, _func)					\
static ssize_t dasd_##_name##_show(struct device *dev,			\
				   struct device_attribute *attr,	\
				   char *buf)				\
{									\
	struct ccw_device *cdev = to_ccwdev(dev);			\
	struct dasd_device *device = dasd_device_from_cdev(cdev);	\
	int val = 0;							\
									\
	if (IS_ERR(device))						\
		return -ENODEV;						\
	if (device->discipline && _func)				\
		val = _func(device);					\
	dasd_put_device(device);					\
									\
	return sysfs_emit(buf, "%d\n", val);			\
}									\
static DEVICE_ATTR(_name, 0444, dasd_##_name##_show, NULL);

DASD_DEFINE_ATTR(ese, device->discipline->ese_capable);
DASD_DEFINE_ATTR(on_demand_formatting, device->discipline->on_demand_format);
DASD_DEFINE_ATTR(extent_size, device->discipline->ext_size);
DASD_DEFINE_ATTR(pool_id, device->discipline->ext_pool_id);
DASD_DEFINE_ATTR(space_configured, device->discipline->space_configured);
DASD_DEFINE_ATTR(space_allocated, device->discipline->space_allocated);
DASD_DEFINE_ATTR(logical_capacity, device->discipline->logical_capacity);
DASD_DEFINE_ATTR(warn_threshold, device->discipline->ext_pool_warn_thrshld);
DASD_DEFINE_ATTR(cap_at_warnlevel, device->discipline->ext_pool_cap_at_warnlevel);
DASD_DEFINE_ATTR(pool_oos, device->discipline->ext_pool_oos);

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_full_track_bias.attr,
	&dev_attr_ese_heuristic_state.attr,
	&dev_attr_retries.attr,
	&dev_attr_timeout.attr,
	&dev_attr_reservation_policy.attr,
	&dev_attr_last_known_reservation_state.attr,
	&dev_attr_safe_offline.attr,
	&dev_attr_host_access_count.attr,
	&dev_attr_path_masks.attr,
	&dev_attr_path_threshold.attr,
	&dev_attr_path_autodisable.attr,
	&dev_attr_path_interval.attr,
	&dev_attr_path_reset.attr,
	&dev_attr_hpf.attr,
	&dev_attr_ese.attr,
	&dev_attr_on_demand_formatting.attr,
	&dev_attr_fc_security.attr,
	&dev_attr_copy_pair.attr,
	&dev_attr_copy_role.attr,
	&dev_attr_ping.attr,
	&dev_attr_aq_mask.attr,
	&dev_attr_aq_requeue.attr,
	&dev_attr_aq_timeouts.attr,
	NULL,
};

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

static struct attribute *capacity_attrs[] = {
	&dev_attr_space_configured.attr,
	&dev_attr_space_allocated.attr,
	&dev_attr_logical_capacity.attr,
	NULL,
};

static const struct attribute_group capacity_attr_group = {
	.name = "capacity",
	.attrs = capacity_attrs,
};

static struct attribute *ext_pool_attrs[] = {
	&dev_attr_pool_id.attr,
	&dev_attr_extent_size.attr,
	&dev_attr_warn_threshold.attr,
	&dev_attr_cap_at_warnlevel.attr,
	&dev_attr_pool_oos.attr,
	NULL,
};

static const struct attribute_group ext_pool_attr_group = {
	.name = "extent_pool",
	.attrs = ext_pool_attrs,
};

const struct attribute_group *dasd_dev_groups[] = {
	&dasd_attr_group,
	&capacity_attr_group,
	&ext_pool_attr_group,
	NULL,
};
EXPORT_SYMBOL_GPL(dasd_dev_groups);

/*
 * 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 whether 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_devmap_from_cdev(cdev);
	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;
}
EXPORT_SYMBOL(dasd_set_feature);

static struct attribute *paths_info_attrs[] = {
	&path_fcs_attribute.attr,
	NULL,
};
ATTRIBUTE_GROUPS(paths_info);

static struct kobj_type path_attr_type = {
	.release	= dasd_path_release,
	.default_groups	= paths_info_groups,
	.sysfs_ops	= &kobj_sysfs_ops,
};

static void dasd_path_init_kobj(struct dasd_device *device, int chp)
{
	device->path[chp].kobj.kset = device->paths_info;
	kobject_init(&device->path[chp].kobj, &path_attr_type);
}

void dasd_path_create_kobj(struct dasd_device *device, int chp)
{
	int rc;

	if (test_bit(DASD_FLAG_OFFLINE, &device->flags))
		return;
	if (!device->paths_info) {
		dev_warn(&device->cdev->dev, "Unable to create paths objects\n");
		return;
	}
	if (device->path[chp].in_sysfs)
		return;
	if (!device->path[chp].conf_data)
		return;

	dasd_path_init_kobj(device, chp);

	rc = kobject_add(&device->path[chp].kobj, NULL, "%x.%02x",
			 device->path[chp].cssid, device->path[chp].chpid);
	if (rc)
		kobject_put(&device->path[chp].kobj);
	device->path[chp].in_sysfs = true;
}
EXPORT_SYMBOL(dasd_path_create_kobj);

void dasd_path_create_kobjects(struct dasd_device *device)
{
	u8 lpm, opm;

	opm = dasd_path_get_opm(device);
	for (lpm = 0x80; lpm; lpm >>= 1) {
		if (!(lpm & opm))
			continue;
		dasd_path_create_kobj(device, pathmask_to_pos(lpm));
	}
}
EXPORT_SYMBOL(dasd_path_create_kobjects);

static void dasd_path_remove_kobj(struct dasd_device *device, int chp)
{
	if (device->path[chp].in_sysfs) {
		kobject_put(&device->path[chp].kobj);
		device->path[chp].in_sysfs = false;
	}
}

/*
 * As we keep kobjects for the lifetime of a device, this function must not be
 * called anywhere but in the context of offlining a device.
 */
void dasd_path_remove_kobjects(struct dasd_device *device)
{
	int i;

	for (i = 0; i < 8; i++)
		dasd_path_remove_kobj(device, i);
}
EXPORT_SYMBOL(dasd_path_remove_kobjects);

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();
}