Initial import

1 files changed, 3879 insertions, 0 deletions

diff --git a/drivers/s390/block/dasd.c b/drivers/s390/block/dasd.c
new file mode 100644
index 000000000..57fd66357
--- /dev/null
+++ b/drivers/s390/block/dasd.c
@@ -0,0 +1,3879 @@
+/*
+ * 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, 2009
+ */
+
+#define KMSG_COMPONENT "dasd"
+#define pr_fmt(fmt) KMSG_COMPONENT ": " fmt
+
+#include <linux/kmod.h>
+#include <linux/init.h>
+#include <linux/interrupt.h>
+#include <linux/ctype.h>
+#include <linux/major.h>
+#include <linux/slab.h>
+#include <linux/hdreg.h>
+#include <linux/async.h>
+#include <linux/mutex.h>
+#include <linux/debugfs.h>
+#include <linux/seq_file.h>
+#include <linux/vmalloc.h>
+
+#include <asm/ccwdev.h>
+#include <asm/ebcdic.h>
+#include <asm/idals.h>
+#include <asm/itcw.h>
+#include <asm/diag.h>
+
+/* This is ugly... */
+#define PRINTK_HEADER "dasd:"
+
+#include "dasd_int.h"
+/*
+ * SECTION: Constant definitions to be used within this file
+ */
+#define DASD_CHANQ_MAX_SIZE 4
+
+/*
+ * SECTION: exported variables of dasd.c
+ */
+debug_info_t *dasd_debug_area;
+EXPORT_SYMBOL(dasd_debug_area);
+static struct dentry *dasd_debugfs_root_entry;
+struct dasd_discipline *dasd_diag_discipline_pointer;
+EXPORT_SYMBOL(dasd_diag_discipline_pointer);
+void dasd_int_handler(struct ccw_device *, unsigned long, struct irb *);
+
+MODULE_AUTHOR("Holger Smolinski <Holger.Smolinski@de.ibm.com>");
+MODULE_DESCRIPTION("Linux on S/390 DASD device driver,"
+		   " Copyright IBM Corp. 2000");
+MODULE_SUPPORTED_DEVICE("dasd");
+MODULE_LICENSE("GPL");
+
+/*
+ * SECTION: prototypes for static functions of dasd.c
+ */
+static int  dasd_alloc_queue(struct dasd_block *);
+static void dasd_setup_queue(struct dasd_block *);
+static void dasd_free_queue(struct dasd_block *);
+static void dasd_flush_request_queue(struct dasd_block *);
+static int dasd_flush_block_queue(struct dasd_block *);
+static void dasd_device_tasklet(struct dasd_device *);
+static void dasd_block_tasklet(struct dasd_block *);
+static void do_kick_device(struct work_struct *);
+static void do_restore_device(struct work_struct *);
+static void do_reload_device(struct work_struct *);
+static void dasd_return_cqr_cb(struct dasd_ccw_req *, void *);
+static void dasd_device_timeout(unsigned long);
+static void dasd_block_timeout(unsigned long);
+static void __dasd_process_erp(struct dasd_device *, struct dasd_ccw_req *);
+static void dasd_profile_init(struct dasd_profile *, struct dentry *);
+static void dasd_profile_exit(struct dasd_profile *);
+
+/*
+ * SECTION: Operations on the device structure.
+ */
+static wait_queue_head_t dasd_init_waitq;
+static wait_queue_head_t dasd_flush_wq;
+static wait_queue_head_t generic_waitq;
+static wait_queue_head_t shutdown_waitq;
+
+/*
+ * Allocate memory for a new device structure.
+ */
+struct dasd_device *dasd_alloc_device(void)
+{
+	struct dasd_device *device;
+
+	device = kzalloc(sizeof(struct dasd_device), GFP_ATOMIC);
+	if (!device)
+		return ERR_PTR(-ENOMEM);
+
+	/* Get two pages for normal block device operations. */
+	device->ccw_mem = (void *) __get_free_pages(GFP_ATOMIC | GFP_DMA, 1);
+	if (!device->ccw_mem) {
+		kfree(device);
+		return ERR_PTR(-ENOMEM);
+	}
+	/* Get one page for error recovery. */
+	device->erp_mem = (void *) get_zeroed_page(GFP_ATOMIC | GFP_DMA);
+	if (!device->erp_mem) {
+		free_pages((unsigned long) device->ccw_mem, 1);
+		kfree(device);
+		return ERR_PTR(-ENOMEM);
+	}
+
+	dasd_init_chunklist(&device->ccw_chunks, device->ccw_mem, PAGE_SIZE*2);
+	dasd_init_chunklist(&device->erp_chunks, device->erp_mem, PAGE_SIZE);
+	spin_lock_init(&device->mem_lock);
+	atomic_set(&device->tasklet_scheduled, 0);
+	tasklet_init(&device->tasklet,
+		     (void (*)(unsigned long)) dasd_device_tasklet,
+		     (unsigned long) device);
+	INIT_LIST_HEAD(&device->ccw_queue);
+	init_timer(&device->timer);
+	device->timer.function = dasd_device_timeout;
+	device->timer.data = (unsigned long) device;
+	INIT_WORK(&device->kick_work, do_kick_device);
+	INIT_WORK(&device->restore_device, do_restore_device);
+	INIT_WORK(&device->reload_device, do_reload_device);
+	device->state = DASD_STATE_NEW;
+	device->target = DASD_STATE_NEW;
+	mutex_init(&device->state_mutex);
+	spin_lock_init(&device->profile.lock);
+	return device;
+}
+
+/*
+ * Free memory of a device structure.
+ */
+void dasd_free_device(struct dasd_device *device)
+{
+	kfree(device->private);
+	free_page((unsigned long) device->erp_mem);
+	free_pages((unsigned long) device->ccw_mem, 1);
+	kfree(device);
+}
+
+/*
+ * Allocate memory for a new device structure.
+ */
+struct dasd_block *dasd_alloc_block(void)
+{
+	struct dasd_block *block;
+
+	block = kzalloc(sizeof(*block), GFP_ATOMIC);
+	if (!block)
+		return ERR_PTR(-ENOMEM);
+	/* open_count = 0 means device online but not in use */
+	atomic_set(&block->open_count, -1);
+
+	spin_lock_init(&block->request_queue_lock);
+	atomic_set(&block->tasklet_scheduled, 0);
+	tasklet_init(&block->tasklet,
+		     (void (*)(unsigned long)) dasd_block_tasklet,
+		     (unsigned long) block);
+	INIT_LIST_HEAD(&block->ccw_queue);
+	spin_lock_init(&block->queue_lock);
+	init_timer(&block->timer);
+	block->timer.function = dasd_block_timeout;
+	block->timer.data = (unsigned long) block;
+	spin_lock_init(&block->profile.lock);
+
+	return block;
+}
+EXPORT_SYMBOL_GPL(dasd_alloc_block);
+
+/*
+ * Free memory of a device structure.
+ */
+void dasd_free_block(struct dasd_block *block)
+{
+	kfree(block);
+}
+EXPORT_SYMBOL_GPL(dasd_free_block);
+
+/*
+ * Make a new device known to the system.
+ */
+static int dasd_state_new_to_known(struct dasd_device *device)
+{
+	int rc;
+
+	/*
+	 * As long as the device is not in state DASD_STATE_NEW we want to
+	 * keep the reference count > 0.
+	 */
+	dasd_get_device(device);
+
+	if (device->block) {
+		rc = dasd_alloc_queue(device->block);
+		if (rc) {
+			dasd_put_device(device);
+			return rc;
+		}
+	}
+	device->state = DASD_STATE_KNOWN;
+	return 0;
+}
+
+/*
+ * Let the system forget about a device.
+ */
+static int dasd_state_known_to_new(struct dasd_device *device)
+{
+	/* Disable extended error reporting for this device. */
+	dasd_eer_disable(device);
+	/* Forget the discipline information. */
+	if (device->discipline) {
+		if (device->discipline->uncheck_device)
+			device->discipline->uncheck_device(device);
+		module_put(device->discipline->owner);
+	}
+	device->discipline = NULL;
+	if (device->base_discipline)
+		module_put(device->base_discipline->owner);
+	device->base_discipline = NULL;
+	device->state = DASD_STATE_NEW;
+
+	if (device->block)
+		dasd_free_queue(device->block);
+
+	/* Give up reference we took in dasd_state_new_to_known. */
+	dasd_put_device(device);
+	return 0;
+}
+
+static struct dentry *dasd_debugfs_setup(const char *name,
+					 struct dentry *base_dentry)
+{
+	struct dentry *pde;
+
+	if (!base_dentry)
+		return NULL;
+	pde = debugfs_create_dir(name, base_dentry);
+	if (!pde || IS_ERR(pde))
+		return NULL;
+	return pde;
+}
+
+/*
+ * Request the irq line for the device.
+ */
+static int dasd_state_known_to_basic(struct dasd_device *device)
+{
+	struct dasd_block *block = device->block;
+	int rc = 0;
+
+	/* Allocate and register gendisk structure. */
+	if (block) {
+		rc = dasd_gendisk_alloc(block);
+		if (rc)
+			return rc;
+		block->debugfs_dentry =
+			dasd_debugfs_setup(block->gdp->disk_name,
+					   dasd_debugfs_root_entry);
+		dasd_profile_init(&block->profile, block->debugfs_dentry);
+		if (dasd_global_profile_level == DASD_PROFILE_ON)
+			dasd_profile_on(&device->block->profile);
+	}
+	device->debugfs_dentry =
+		dasd_debugfs_setup(dev_name(&device->cdev->dev),
+				   dasd_debugfs_root_entry);
+	dasd_profile_init(&device->profile, device->debugfs_dentry);
+
+	/* register 'device' debug area, used for all DBF_DEV_XXX calls */
+	device->debug_area = debug_register(dev_name(&device->cdev->dev), 4, 1,
+					    8 * sizeof(long));
+	debug_register_view(device->debug_area, &debug_sprintf_view);
+	debug_set_level(device->debug_area, DBF_WARNING);
+	DBF_DEV_EVENT(DBF_EMERG, device, "%s", "debug area created");
+
+	device->state = DASD_STATE_BASIC;
+
+	return rc;
+}
+
+/*
+ * Release the irq line for the device. Terminate any running i/o.
+ */
+static int dasd_state_basic_to_known(struct dasd_device *device)
+{
+	int rc;
+
+	if (device->discipline->basic_to_known) {
+		rc = device->discipline->basic_to_known(device);
+		if (rc)
+			return rc;
+	}
+
+	if (device->block) {
+		dasd_profile_exit(&device->block->profile);
+		debugfs_remove(device->block->debugfs_dentry);
+		dasd_gendisk_free(device->block);
+		dasd_block_clear_timer(device->block);
+	}
+	rc = dasd_flush_device_queue(device);
+	if (rc)
+		return rc;
+	dasd_device_clear_timer(device);
+	dasd_profile_exit(&device->profile);
+	debugfs_remove(device->debugfs_dentry);
+	DBF_DEV_EVENT(DBF_EMERG, device, "%p debug area deleted", device);
+	if (device->debug_area != NULL) {
+		debug_unregister(device->debug_area);
+		device->debug_area = NULL;
+	}
+	device->state = DASD_STATE_KNOWN;
+	return 0;
+}
+
+/*
+ * Do the initial analysis. The do_analysis function may return
+ * -EAGAIN in which case the device keeps the state DASD_STATE_BASIC
+ * until the discipline decides to continue the startup sequence
+ * by calling the function dasd_change_state. The eckd disciplines
+ * uses this to start a ccw that detects the format. The completion
+ * interrupt for this detection ccw uses the kernel event daemon to
+ * trigger the call to dasd_change_state. All this is done in the
+ * discipline code, see dasd_eckd.c.
+ * After the analysis ccw is done (do_analysis returned 0) the block
+ * device is setup.
+ * In case the analysis returns an error, the device setup is stopped
+ * (a fake disk was already added to allow formatting).
+ */
+static int dasd_state_basic_to_ready(struct dasd_device *device)
+{
+	int rc;
+	struct dasd_block *block;
+
+	rc = 0;
+	block = device->block;
+	/* make disk known with correct capacity */
+	if (block) {
+		if (block->base->discipline->do_analysis != NULL)
+			rc = block->base->discipline->do_analysis(block);
+		if (rc) {
+			if (rc != -EAGAIN) {
+				device->state = DASD_STATE_UNFMT;
+				goto out;
+			}
+			return rc;
+		}
+		dasd_setup_queue(block);
+		set_capacity(block->gdp,
+			     block->blocks << block->s2b_shift);
+		device->state = DASD_STATE_READY;
+		rc = dasd_scan_partitions(block);
+		if (rc) {
+			device->state = DASD_STATE_BASIC;
+			return rc;
+		}
+	} else {
+		device->state = DASD_STATE_READY;
+	}
+out:
+	if (device->discipline->basic_to_ready)
+		rc = device->discipline->basic_to_ready(device);
+	return rc;
+}
+
+static inline
+int _wait_for_empty_queues(struct dasd_device *device)
+{
+	if (device->block)
+		return list_empty(&device->ccw_queue) &&
+			list_empty(&device->block->ccw_queue);
+	else
+		return list_empty(&device->ccw_queue);
+}
+
+/*
+ * Remove device from block device layer. Destroy dirty buffers.
+ * Forget format information. Check if the target level is basic
+ * and if it is create fake disk for formatting.
+ */
+static int dasd_state_ready_to_basic(struct dasd_device *device)
+{
+	int rc;
+
+	device->state = DASD_STATE_BASIC;
+	if (device->block) {
+		struct dasd_block *block = device->block;
+		rc = dasd_flush_block_queue(block);
+		if (rc) {
+			device->state = DASD_STATE_READY;
+			return rc;
+		}
+		dasd_flush_request_queue(block);
+		dasd_destroy_partitions(block);
+		block->blocks = 0;
+		block->bp_block = 0;
+		block->s2b_shift = 0;
+	}
+	return 0;
+}
+
+/*
+ * Back to basic.
+ */
+static int dasd_state_unfmt_to_basic(struct dasd_device *device)
+{
+	device->state = DASD_STATE_BASIC;
+	return 0;
+}
+
+/*
+ * Make the device online and schedule the bottom half to start
+ * the requeueing of requests from the linux request queue to the
+ * ccw queue.
+ */
+static int
+dasd_state_ready_to_online(struct dasd_device * device)
+{
+	struct gendisk *disk;
+	struct disk_part_iter piter;
+	struct hd_struct *part;
+
+	device->state = DASD_STATE_ONLINE;
+	if (device->block) {
+		dasd_schedule_block_bh(device->block);
+		if ((device->features & DASD_FEATURE_USERAW)) {
+			disk = device->block->gdp;
+			kobject_uevent(&disk_to_dev(disk)->kobj, KOBJ_CHANGE);
+			return 0;
+		}
+		disk = device->block->bdev->bd_disk;
+		disk_part_iter_init(&piter, disk, DISK_PITER_INCL_PART0);
+		while ((part = disk_part_iter_next(&piter)))
+			kobject_uevent(&part_to_dev(part)->kobj, KOBJ_CHANGE);
+		disk_part_iter_exit(&piter);
+	}
+	return 0;
+}
+
+/*
+ * Stop the requeueing of requests again.
+ */
+static int dasd_state_online_to_ready(struct dasd_device *device)
+{
+	int rc;
+	struct gendisk *disk;
+	struct disk_part_iter piter;
+	struct hd_struct *part;
+
+	if (device->discipline->online_to_ready) {
+		rc = device->discipline->online_to_ready(device);
+		if (rc)
+			return rc;
+	}
+
+	device->state = DASD_STATE_READY;
+	if (device->block && !(device->features & DASD_FEATURE_USERAW)) {
+		disk = device->block->bdev->bd_disk;
+		disk_part_iter_init(&piter, disk, DISK_PITER_INCL_PART0);
+		while ((part = disk_part_iter_next(&piter)))
+			kobject_uevent(&part_to_dev(part)->kobj, KOBJ_CHANGE);
+		disk_part_iter_exit(&piter);
+	}
+	return 0;
+}
+
+/*
+ * Device startup state changes.
+ */
+static int dasd_increase_state(struct dasd_device *device)
+{
+	int rc;
+
+	rc = 0;
+	if (device->state == DASD_STATE_NEW &&
+	    device->target >= DASD_STATE_KNOWN)
+		rc = dasd_state_new_to_known(device);
+
+	if (!rc &&
+	    device->state == DASD_STATE_KNOWN &&
+	    device->target >= DASD_STATE_BASIC)
+		rc = dasd_state_known_to_basic(device);
+
+	if (!rc &&
+	    device->state == DASD_STATE_BASIC &&
+	    device->target >= DASD_STATE_READY)
+		rc = dasd_state_basic_to_ready(device);
+
+	if (!rc &&
+	    device->state == DASD_STATE_UNFMT &&
+	    device->target > DASD_STATE_UNFMT)
+		rc = -EPERM;
+
+	if (!rc &&
+	    device->state == DASD_STATE_READY &&
+	    device->target >= DASD_STATE_ONLINE)
+		rc = dasd_state_ready_to_online(device);
+
+	return rc;
+}
+
+/*
+ * Device shutdown state changes.
+ */
+static int dasd_decrease_state(struct dasd_device *device)
+{
+	int rc;
+
+	rc = 0;
+	if (device->state == DASD_STATE_ONLINE &&
+	    device->target <= DASD_STATE_READY)
+		rc = dasd_state_online_to_ready(device);
+
+	if (!rc &&
+	    device->state == DASD_STATE_READY &&
+	    device->target <= DASD_STATE_BASIC)
+		rc = dasd_state_ready_to_basic(device);
+
+	if (!rc &&
+	    device->state == DASD_STATE_UNFMT &&
+	    device->target <= DASD_STATE_BASIC)
+		rc = dasd_state_unfmt_to_basic(device);
+
+	if (!rc &&
+	    device->state == DASD_STATE_BASIC &&
+	    device->target <= DASD_STATE_KNOWN)
+		rc = dasd_state_basic_to_known(device);
+
+	if (!rc &&
+	    device->state == DASD_STATE_KNOWN &&
+	    device->target <= DASD_STATE_NEW)
+		rc = dasd_state_known_to_new(device);
+
+	return rc;
+}
+
+/*
+ * This is the main startup/shutdown routine.
+ */
+static void dasd_change_state(struct dasd_device *device)
+{
+	int rc;
+
+	if (device->state == device->target)
+		/* Already where we want to go today... */
+		return;
+	if (device->state < device->target)
+		rc = dasd_increase_state(device);
+	else
+		rc = dasd_decrease_state(device);
+	if (rc == -EAGAIN)
+		return;
+	if (rc)
+		device->target = device->state;
+
+	/* let user-space know that the device status changed */
+	kobject_uevent(&device->cdev->dev.kobj, KOBJ_CHANGE);
+
+	if (device->state == device->target)
+		wake_up(&dasd_init_waitq);
+}
+
+/*
+ * Kick starter for devices that did not complete the startup/shutdown
+ * procedure or were sleeping because of a pending state.
+ * dasd_kick_device will schedule a call do do_kick_device to the kernel
+ * event daemon.
+ */
+static void do_kick_device(struct work_struct *work)
+{
+	struct dasd_device *device = container_of(work, struct dasd_device, kick_work);
+	mutex_lock(&device->state_mutex);
+	dasd_change_state(device);
+	mutex_unlock(&device->state_mutex);
+	dasd_schedule_device_bh(device);
+	dasd_put_device(device);
+}
+
+void dasd_kick_device(struct dasd_device *device)
+{
+	dasd_get_device(device);
+	/* queue call to dasd_kick_device to the kernel event daemon. */
+	if (!schedule_work(&device->kick_work))
+		dasd_put_device(device);
+}
+EXPORT_SYMBOL(dasd_kick_device);
+
+/*
+ * dasd_reload_device will schedule a call do do_reload_device to the kernel
+ * event daemon.
+ */
+static void do_reload_device(struct work_struct *work)
+{
+	struct dasd_device *device = container_of(work, struct dasd_device,
+						  reload_device);
+	device->discipline->reload(device);
+	dasd_put_device(device);
+}
+
+void dasd_reload_device(struct dasd_device *device)
+{
+	dasd_get_device(device);
+	/* queue call to dasd_reload_device to the kernel event daemon. */
+	if (!schedule_work(&device->reload_device))
+		dasd_put_device(device);
+}
+EXPORT_SYMBOL(dasd_reload_device);
+
+/*
+ * dasd_restore_device will schedule a call do do_restore_device to the kernel
+ * event daemon.
+ */
+static void do_restore_device(struct work_struct *work)
+{
+	struct dasd_device *device = container_of(work, struct dasd_device,
+						  restore_device);
+	device->cdev->drv->restore(device->cdev);
+	dasd_put_device(device);
+}
+
+void dasd_restore_device(struct dasd_device *device)
+{
+	dasd_get_device(device);
+	/* queue call to dasd_restore_device to the kernel event daemon. */
+	if (!schedule_work(&device->restore_device))
+		dasd_put_device(device);
+}
+
+/*
+ * Set the target state for a device and starts the state change.
+ */
+void dasd_set_target_state(struct dasd_device *device, int target)
+{
+	dasd_get_device(device);
+	mutex_lock(&device->state_mutex);
+	/* If we are in probeonly mode stop at DASD_STATE_READY. */
+	if (dasd_probeonly && target > DASD_STATE_READY)
+		target = DASD_STATE_READY;
+	if (device->target != target) {
+		if (device->state == target)
+			wake_up(&dasd_init_waitq);
+		device->target = target;
+	}
+	if (device->state != device->target)
+		dasd_change_state(device);
+	mutex_unlock(&device->state_mutex);
+	dasd_put_device(device);
+}
+EXPORT_SYMBOL(dasd_set_target_state);
+
+/*
+ * Enable devices with device numbers in [from..to].
+ */
+static inline int _wait_for_device(struct dasd_device *device)
+{
+	return (device->state == device->target);
+}
+
+void dasd_enable_device(struct dasd_device *device)
+{
+	dasd_set_target_state(device, DASD_STATE_ONLINE);
+	if (device->state <= DASD_STATE_KNOWN)
+		/* No discipline for device found. */
+		dasd_set_target_state(device, DASD_STATE_NEW);
+	/* Now wait for the devices to come up. */
+	wait_event(dasd_init_waitq, _wait_for_device(device));
+
+	dasd_reload_device(device);
+	if (device->discipline->kick_validate)
+		device->discipline->kick_validate(device);
+}
+EXPORT_SYMBOL(dasd_enable_device);
+
+/*
+ * SECTION: device operation (interrupt handler, start i/o, term i/o ...)
+ */
+
+unsigned int dasd_global_profile_level = DASD_PROFILE_OFF;
+
+#ifdef CONFIG_DASD_PROFILE
+struct dasd_profile dasd_global_profile = {
+	.lock = __SPIN_LOCK_UNLOCKED(dasd_global_profile.lock),
+};
+static struct dentry *dasd_debugfs_global_entry;
+
+/*
+ * Add profiling information for cqr before execution.
+ */
+static void dasd_profile_start(struct dasd_block *block,
+			       struct dasd_ccw_req *cqr,
+			       struct request *req)
+{
+	struct list_head *l;
+	unsigned int counter;
+	struct dasd_device *device;
+
+	/* count the length of the chanq for statistics */
+	counter = 0;
+	if (dasd_global_profile_level || block->profile.data)
+		list_for_each(l, &block->ccw_queue)
+			if (++counter >= 31)
+				break;
+
+	spin_lock(&dasd_global_profile.lock);
+	if (dasd_global_profile.data) {
+		dasd_global_profile.data->dasd_io_nr_req[counter]++;
+		if (rq_data_dir(req) == READ)
+			dasd_global_profile.data->dasd_read_nr_req[counter]++;
+	}
+	spin_unlock(&dasd_global_profile.lock);
+
+	spin_lock(&block->profile.lock);
+	if (block->profile.data) {
+		block->profile.data->dasd_io_nr_req[counter]++;
+		if (rq_data_dir(req) == READ)
+			block->profile.data->dasd_read_nr_req[counter]++;
+	}
+	spin_unlock(&block->profile.lock);
+
+	/*
+	 * We count the request for the start device, even though it may run on
+	 * some other device due to error recovery. This way we make sure that
+	 * we count each request only once.
+	 */
+	device = cqr->startdev;
+	if (device->profile.data) {
+		counter = 1; /* request is not yet queued on the start device */
+		list_for_each(l, &device->ccw_queue)
+			if (++counter >= 31)
+				break;
+	}
+	spin_lock(&device->profile.lock);
+	if (device->profile.data) {
+		device->profile.data->dasd_io_nr_req[counter]++;
+		if (rq_data_dir(req) == READ)
+			device->profile.data->dasd_read_nr_req[counter]++;
+	}
+	spin_unlock(&device->profile.lock);
+}
+
+/*
+ * Add profiling information for cqr after execution.
+ */
+
+#define dasd_profile_counter(value, index)			   \
+{								   \
+	for (index = 0; index < 31 && value >> (2+index); index++) \
+		;						   \
+}
+
+static void dasd_profile_end_add_data(struct dasd_profile_info *data,
+				      int is_alias,
+				      int is_tpm,
+				      int is_read,
+				      long sectors,
+				      int sectors_ind,
+				      int tottime_ind,
+				      int tottimeps_ind,
+				      int strtime_ind,
+				      int irqtime_ind,
+				      int irqtimeps_ind,
+				      int endtime_ind)
+{
+	/* in case of an overflow, reset the whole profile */
+	if (data->dasd_io_reqs == UINT_MAX) {
+			memset(data, 0, sizeof(*data));
+			getnstimeofday(&data->starttod);
+	}
+	data->dasd_io_reqs++;
+	data->dasd_io_sects += sectors;
+	if (is_alias)
+		data->dasd_io_alias++;
+	if (is_tpm)
+		data->dasd_io_tpm++;
+
+	data->dasd_io_secs[sectors_ind]++;
+	data->dasd_io_times[tottime_ind]++;
+	data->dasd_io_timps[tottimeps_ind]++;
+	data->dasd_io_time1[strtime_ind]++;
+	data->dasd_io_time2[irqtime_ind]++;
+	data->dasd_io_time2ps[irqtimeps_ind]++;
+	data->dasd_io_time3[endtime_ind]++;
+
+	if (is_read) {
+		data->dasd_read_reqs++;
+		data->dasd_read_sects += sectors;
+		if (is_alias)
+			data->dasd_read_alias++;
+		if (is_tpm)
+			data->dasd_read_tpm++;
+		data->dasd_read_secs[sectors_ind]++;
+		data->dasd_read_times[tottime_ind]++;
+		data->dasd_read_time1[strtime_ind]++;
+		data->dasd_read_time2[irqtime_ind]++;
+		data->dasd_read_time3[endtime_ind]++;
+	}
+}
+
+static void dasd_profile_end(struct dasd_block *block,
+			     struct dasd_ccw_req *cqr,
+			     struct request *req)
+{
+	long strtime, irqtime, endtime, tottime;	/* in microseconds */
+	long tottimeps, sectors;
+	struct dasd_device *device;
+	int sectors_ind, tottime_ind, tottimeps_ind, strtime_ind;
+	int irqtime_ind, irqtimeps_ind, endtime_ind;
+
+	device = cqr->startdev;
+	if (!(dasd_global_profile_level ||
+	      block->profile.data ||
+	      device->profile.data))
+		return;
+
+	sectors = blk_rq_sectors(req);
+	if (!cqr->buildclk || !cqr->startclk ||
+	    !cqr->stopclk || !cqr->endclk ||
+	    !sectors)
+		return;
+
+	strtime = ((cqr->startclk - cqr->buildclk) >> 12);
+	irqtime = ((cqr->stopclk - cqr->startclk) >> 12);
+	endtime = ((cqr->endclk - cqr->stopclk) >> 12);
+	tottime = ((cqr->endclk - cqr->buildclk) >> 12);
+	tottimeps = tottime / sectors;
+
+	dasd_profile_counter(sectors, sectors_ind);
+	dasd_profile_counter(tottime, tottime_ind);
+	dasd_profile_counter(tottimeps, tottimeps_ind);
+	dasd_profile_counter(strtime, strtime_ind);
+	dasd_profile_counter(irqtime, irqtime_ind);
+	dasd_profile_counter(irqtime / sectors, irqtimeps_ind);
+	dasd_profile_counter(endtime, endtime_ind);
+
+	spin_lock(&dasd_global_profile.lock);
+	if (dasd_global_profile.data) {
+		dasd_profile_end_add_data(dasd_global_profile.data,
+					  cqr->startdev != block->base,
+					  cqr->cpmode == 1,
+					  rq_data_dir(req) == READ,
+					  sectors, sectors_ind, tottime_ind,
+					  tottimeps_ind, strtime_ind,
+					  irqtime_ind, irqtimeps_ind,
+					  endtime_ind);
+	}
+	spin_unlock(&dasd_global_profile.lock);
+
+	spin_lock(&block->profile.lock);
+	if (block->profile.data)
+		dasd_profile_end_add_data(block->profile.data,
+					  cqr->startdev != block->base,
+					  cqr->cpmode == 1,
+					  rq_data_dir(req) == READ,
+					  sectors, sectors_ind, tottime_ind,
+					  tottimeps_ind, strtime_ind,
+					  irqtime_ind, irqtimeps_ind,
+					  endtime_ind);
+	spin_unlock(&block->profile.lock);
+
+	spin_lock(&device->profile.lock);
+	if (device->profile.data)
+		dasd_profile_end_add_data(device->profile.data,
+					  cqr->startdev != block->base,
+					  cqr->cpmode == 1,
+					  rq_data_dir(req) == READ,
+					  sectors, sectors_ind, tottime_ind,
+					  tottimeps_ind, strtime_ind,
+					  irqtime_ind, irqtimeps_ind,
+					  endtime_ind);
+	spin_unlock(&device->profile.lock);
+}
+
+void dasd_profile_reset(struct dasd_profile *profile)
+{
+	struct dasd_profile_info *data;
+
+	spin_lock_bh(&profile->lock);
+	data = profile->data;
+	if (!data) {
+		spin_unlock_bh(&profile->lock);
+		return;
+	}
+	memset(data, 0, sizeof(*data));
+	getnstimeofday(&data->starttod);
+	spin_unlock_bh(&profile->lock);
+}
+
+int dasd_profile_on(struct dasd_profile *profile)
+{
+	struct dasd_profile_info *data;
+
+	data = kzalloc(sizeof(*data), GFP_KERNEL);
+	if (!data)
+		return -ENOMEM;
+	spin_lock_bh(&profile->lock);
+	if (profile->data) {
+		spin_unlock_bh(&profile->lock);
+		kfree(data);
+		return 0;
+	}
+	getnstimeofday(&data->starttod);
+	profile->data = data;
+	spin_unlock_bh(&profile->lock);
+	return 0;
+}
+
+void dasd_profile_off(struct dasd_profile *profile)
+{
+	spin_lock_bh(&profile->lock);
+	kfree(profile->data);
+	profile->data = NULL;
+	spin_unlock_bh(&profile->lock);
+}
+
+char *dasd_get_user_string(const char __user *user_buf, size_t user_len)
+{
+	char *buffer;
+
+	buffer = vmalloc(user_len + 1);
+	if (buffer == NULL)
+		return ERR_PTR(-ENOMEM);
+	if (copy_from_user(buffer, user_buf, user_len) != 0) {
+		vfree(buffer);
+		return ERR_PTR(-EFAULT);
+	}
+	/* got the string, now strip linefeed. */
+	if (buffer[user_len - 1] == '\n')
+		buffer[user_len - 1] = 0;
+	else
+		buffer[user_len] = 0;
+	return buffer;
+}
+
+static ssize_t dasd_stats_write(struct file *file,
+				const char __user *user_buf,
+				size_t user_len, loff_t *pos)
+{
+	char *buffer, *str;
+	int rc;
+	struct seq_file *m = (struct seq_file *)file->private_data;
+	struct dasd_profile *prof = m->private;
+
+	if (user_len > 65536)
+		user_len = 65536;
+	buffer = dasd_get_user_string(user_buf, user_len);
+	if (IS_ERR(buffer))
+		return PTR_ERR(buffer);
+
+	str = skip_spaces(buffer);
+	rc = user_len;
+	if (strncmp(str, "reset", 5) == 0) {
+		dasd_profile_reset(prof);
+	} else if (strncmp(str, "on", 2) == 0) {
+		rc = dasd_profile_on(prof);
+		if (rc)
+			goto out;
+		rc = user_len;
+		if (prof == &dasd_global_profile) {
+			dasd_profile_reset(prof);
+			dasd_global_profile_level = DASD_PROFILE_GLOBAL_ONLY;
+		}
+	} else if (strncmp(str, "off", 3) == 0) {
+		if (prof == &dasd_global_profile)
+			dasd_global_profile_level = DASD_PROFILE_OFF;
+		dasd_profile_off(prof);
+	} else
+		rc = -EINVAL;
+out:
+	vfree(buffer);
+	return rc;
+}
+
+static void dasd_stats_array(struct seq_file *m, unsigned int *array)
+{
+	int i;
+
+	for (i = 0; i < 32; i++)
+		seq_printf(m, "%u ", array[i]);
+	seq_putc(m, '\n');
+}
+
+static void dasd_stats_seq_print(struct seq_file *m,
+				 struct dasd_profile_info *data)
+{
+	seq_printf(m, "start_time %ld.%09ld\n",
+		   data->starttod.tv_sec, data->starttod.tv_nsec);
+	seq_printf(m, "total_requests %u\n", data->dasd_io_reqs);
+	seq_printf(m, "total_sectors %u\n", data->dasd_io_sects);
+	seq_printf(m, "total_pav %u\n", data->dasd_io_alias);
+	seq_printf(m, "total_hpf %u\n", data->dasd_io_tpm);
+	seq_puts(m, "histogram_sectors ");
+	dasd_stats_array(m, data->dasd_io_secs);
+	seq_puts(m, "histogram_io_times ");
+	dasd_stats_array(m, data->dasd_io_times);
+	seq_puts(m, "histogram_io_times_weighted ");
+	dasd_stats_array(m, data->dasd_io_timps);
+	seq_puts(m, "histogram_time_build_to_ssch ");
+	dasd_stats_array(m, data->dasd_io_time1);
+	seq_puts(m, "histogram_time_ssch_to_irq ");
+	dasd_stats_array(m, data->dasd_io_time2);
+	seq_puts(m, "histogram_time_ssch_to_irq_weighted ");
+	dasd_stats_array(m, data->dasd_io_time2ps);
+	seq_puts(m, "histogram_time_irq_to_end ");
+	dasd_stats_array(m, data->dasd_io_time3);
+	seq_puts(m, "histogram_ccw_queue_length ");
+	dasd_stats_array(m, data->dasd_io_nr_req);
+	seq_printf(m, "total_read_requests %u\n", data->dasd_read_reqs);
+	seq_printf(m, "total_read_sectors %u\n", data->dasd_read_sects);
+	seq_printf(m, "total_read_pav %u\n", data->dasd_read_alias);
+	seq_printf(m, "total_read_hpf %u\n", data->dasd_read_tpm);
+	seq_puts(m, "histogram_read_sectors ");
+	dasd_stats_array(m, data->dasd_read_secs);
+	seq_puts(m, "histogram_read_times ");
+	dasd_stats_array(m, data->dasd_read_times);
+	seq_puts(m, "histogram_read_time_build_to_ssch ");
+	dasd_stats_array(m, data->dasd_read_time1);
+	seq_puts(m, "histogram_read_time_ssch_to_irq ");
+	dasd_stats_array(m, data->dasd_read_time2);
+	seq_puts(m, "histogram_read_time_irq_to_end ");
+	dasd_stats_array(m, data->dasd_read_time3);
+	seq_puts(m, "histogram_read_ccw_queue_length ");
+	dasd_stats_array(m, data->dasd_read_nr_req);
+}
+
+static int dasd_stats_show(struct seq_file *m, void *v)
+{
+	struct dasd_profile *profile;
+	struct dasd_profile_info *data;
+
+	profile = m->private;
+	spin_lock_bh(&profile->lock);
+	data = profile->data;
+	if (!data) {
+		spin_unlock_bh(&profile->lock);
+		seq_puts(m, "disabled\n");
+		return 0;
+	}
+	dasd_stats_seq_print(m, data);
+	spin_unlock_bh(&profile->lock);
+	return 0;
+}
+
+static int dasd_stats_open(struct inode *inode, struct file *file)
+{
+	struct dasd_profile *profile = inode->i_private;
+	return single_open(file, dasd_stats_show, profile);
+}
+
+static const struct file_operations dasd_stats_raw_fops = {
+	.owner		= THIS_MODULE,
+	.open		= dasd_stats_open,
+	.read		= seq_read,
+	.llseek		= seq_lseek,
+	.release	= single_release,
+	.write		= dasd_stats_write,
+};
+
+static void dasd_profile_init(struct dasd_profile *profile,
+			      struct dentry *base_dentry)
+{
+	umode_t mode;
+	struct dentry *pde;
+
+	if (!base_dentry)
+		return;
+	profile->dentry = NULL;
+	profile->data = NULL;
+	mode = (S_IRUSR | S_IWUSR | S_IFREG);
+	pde = debugfs_create_file("statistics", mode, base_dentry,
+				  profile, &dasd_stats_raw_fops);
+	if (pde && !IS_ERR(pde))
+		profile->dentry = pde;
+	return;
+}
+
+static void dasd_profile_exit(struct dasd_profile *profile)
+{
+	dasd_profile_off(profile);
+	debugfs_remove(profile->dentry);
+	profile->dentry = NULL;
+}
+
+static void dasd_statistics_removeroot(void)
+{
+	dasd_global_profile_level = DASD_PROFILE_OFF;
+	dasd_profile_exit(&dasd_global_profile);
+	debugfs_remove(dasd_debugfs_global_entry);
+	debugfs_remove(dasd_debugfs_root_entry);
+}
+
+static void dasd_statistics_createroot(void)
+{
+	struct dentry *pde;
+
+	dasd_debugfs_root_entry = NULL;
+	pde = debugfs_create_dir("dasd", NULL);
+	if (!pde || IS_ERR(pde))
+		goto error;
+	dasd_debugfs_root_entry = pde;
+	pde = debugfs_create_dir("global", dasd_debugfs_root_entry);
+	if (!pde || IS_ERR(pde))
+		goto error;
+	dasd_debugfs_global_entry = pde;
+	dasd_profile_init(&dasd_global_profile, dasd_debugfs_global_entry);
+	return;
+
+error:
+	DBF_EVENT(DBF_ERR, "%s",
+		  "Creation of the dasd debugfs interface failed");
+	dasd_statistics_removeroot();
+	return;
+}
+
+#else
+#define dasd_profile_start(block, cqr, req) do {} while (0)
+#define dasd_profile_end(block, cqr, req) do {} while (0)
+
+static void dasd_statistics_createroot(void)
+{
+	return;
+}
+
+static void dasd_statistics_removeroot(void)
+{
+	return;
+}
+
+int dasd_stats_generic_show(struct seq_file *m, void *v)
+{
+	seq_puts(m, "Statistics are not activated in this kernel\n");
+	return 0;
+}
+
+static void dasd_profile_init(struct dasd_profile *profile,
+			      struct dentry *base_dentry)
+{
+	return;
+}
+
+static void dasd_profile_exit(struct dasd_profile *profile)
+{
+	return;
+}
+
+int dasd_profile_on(struct dasd_profile *profile)
+{
+	return 0;
+}
+
+#endif				/* CONFIG_DASD_PROFILE */
+
+/*
+ * Allocate memory for a channel program with 'cplength' channel
+ * command words and 'datasize' additional space. There are two
+ * variantes: 1) dasd_kmalloc_request uses kmalloc to get the needed
+ * memory and 2) dasd_smalloc_request uses the static ccw memory
+ * that gets allocated for each device.
+ */
+struct dasd_ccw_req *dasd_kmalloc_request(int magic, int cplength,
+					  int datasize,
+					  struct dasd_device *device)
+{
+	struct dasd_ccw_req *cqr;
+
+	/* Sanity checks */
+	BUG_ON(datasize > PAGE_SIZE ||
+	     (cplength*sizeof(struct ccw1)) > PAGE_SIZE);
+
+	cqr = kzalloc(sizeof(struct dasd_ccw_req), GFP_ATOMIC);
+	if (cqr == NULL)
+		return ERR_PTR(-ENOMEM);
+	cqr->cpaddr = NULL;
+	if (cplength > 0) {
+		cqr->cpaddr = kcalloc(cplength, sizeof(struct ccw1),
+				      GFP_ATOMIC | GFP_DMA);
+		if (cqr->cpaddr == NULL) {
+			kfree(cqr);
+			return ERR_PTR(-ENOMEM);
+		}
+	}
+	cqr->data = NULL;
+	if (datasize > 0) {
+		cqr->data = kzalloc(datasize, GFP_ATOMIC | GFP_DMA);
+		if (cqr->data == NULL) {
+			kfree(cqr->cpaddr);
+			kfree(cqr);
+			return ERR_PTR(-ENOMEM);
+		}
+	}
+	cqr->magic =  magic;
+	set_bit(DASD_CQR_FLAGS_USE_ERP, &cqr->flags);
+	dasd_get_device(device);
+	return cqr;
+}
+EXPORT_SYMBOL(dasd_kmalloc_request);
+
+struct dasd_ccw_req *dasd_smalloc_request(int magic, int cplength,
+					  int datasize,
+					  struct dasd_device *device)
+{
+	unsigned long flags;
+	struct dasd_ccw_req *cqr;
+	char *data;
+	int size;
+
+	size = (sizeof(struct dasd_ccw_req) + 7L) & -8L;
+	if (cplength > 0)
+		size += cplength * sizeof(struct ccw1);
+	if (datasize > 0)
+		size += datasize;
+	spin_lock_irqsave(&device->mem_lock, flags);
+	cqr = (struct dasd_ccw_req *)
+		dasd_alloc_chunk(&device->ccw_chunks, size);
+	spin_unlock_irqrestore(&device->mem_lock, flags);
+	if (cqr == NULL)
+		return ERR_PTR(-ENOMEM);
+	memset(cqr, 0, sizeof(struct dasd_ccw_req));
+	data = (char *) cqr + ((sizeof(struct dasd_ccw_req) + 7L) & -8L);
+	cqr->cpaddr = NULL;
+	if (cplength > 0) {
+		cqr->cpaddr = (struct ccw1 *) data;
+		data += cplength*sizeof(struct ccw1);
+		memset(cqr->cpaddr, 0, cplength*sizeof(struct ccw1));
+	}
+	cqr->data = NULL;
+	if (datasize > 0) {
+		cqr->data = data;
+ 		memset(cqr->data, 0, datasize);
+	}
+	cqr->magic = magic;
+	set_bit(DASD_CQR_FLAGS_USE_ERP, &cqr->flags);
+	dasd_get_device(device);
+	return cqr;
+}
+EXPORT_SYMBOL(dasd_smalloc_request);
+
+/*
+ * Free memory of a channel program. This function needs to free all the
+ * idal lists that might have been created by dasd_set_cda and the
+ * struct dasd_ccw_req itself.
+ */
+void dasd_kfree_request(struct dasd_ccw_req *cqr, struct dasd_device *device)
+{
+	struct ccw1 *ccw;
+
+	/* Clear any idals used for the request. */
+	ccw = cqr->cpaddr;
+	do {
+		clear_normalized_cda(ccw);
+	} while (ccw++->flags & (CCW_FLAG_CC | CCW_FLAG_DC));
+	kfree(cqr->cpaddr);
+	kfree(cqr->data);
+	kfree(cqr);
+	dasd_put_device(device);
+}
+EXPORT_SYMBOL(dasd_kfree_request);
+
+void dasd_sfree_request(struct dasd_ccw_req *cqr, struct dasd_device *device)
+{
+	unsigned long flags;
+
+	spin_lock_irqsave(&device->mem_lock, flags);
+	dasd_free_chunk(&device->ccw_chunks, cqr);
+	spin_unlock_irqrestore(&device->mem_lock, flags);
+	dasd_put_device(device);
+}
+EXPORT_SYMBOL(dasd_sfree_request);
+
+/*
+ * Check discipline magic in cqr.
+ */
+static inline int dasd_check_cqr(struct dasd_ccw_req *cqr)
+{
+	struct dasd_device *device;
+
+	if (cqr == NULL)
+		return -EINVAL;
+	device = cqr->startdev;
+	if (strncmp((char *) &cqr->magic, device->discipline->ebcname, 4)) {
+		DBF_DEV_EVENT(DBF_WARNING, device,
+			    " dasd_ccw_req 0x%08x magic doesn't match"
+			    " discipline 0x%08x",
+			    cqr->magic,
+			    *(unsigned int *) device->discipline->name);
+		return -EINVAL;
+	}
+	return 0;
+}
+
+/*
+ * Terminate the current i/o and set the request to clear_pending.
+ * Timer keeps device runnig.
+ * ccw_device_clear can fail if the i/o subsystem
+ * is in a bad mood.
+ */
+int dasd_term_IO(struct dasd_ccw_req *cqr)
+{
+	struct dasd_device *device;
+	int retries, rc;
+	char errorstring[ERRORLENGTH];
+
+	/* Check the cqr */
+	rc = dasd_check_cqr(cqr);
+	if (rc)
+		return rc;
+	retries = 0;
+	device = (struct dasd_device *) cqr->startdev;
+	while ((retries < 5) && (cqr->status == DASD_CQR_IN_IO)) {
+		rc = ccw_device_clear(device->cdev, (long) cqr);
+		switch (rc) {
+		case 0:	/* termination successful */
+			cqr->status = DASD_CQR_CLEAR_PENDING;
+			cqr->stopclk = get_tod_clock();
+			cqr->starttime = 0;
+			DBF_DEV_EVENT(DBF_DEBUG, device,
+				      "terminate cqr %p successful",
+				      cqr);
+			break;
+		case -ENODEV:
+			DBF_DEV_EVENT(DBF_ERR, device, "%s",
+				      "device gone, retry");
+			break;
+		case -EIO:
+			DBF_DEV_EVENT(DBF_ERR, device, "%s",
+				      "I/O error, retry");
+			break;
+		case -EINVAL:
+			/*
+			 * device not valid so no I/O could be running
+			 * handle CQR as termination successful
+			 */
+			cqr->status = DASD_CQR_CLEARED;
+			cqr->stopclk = get_tod_clock();
+			cqr->starttime = 0;
+			/* no retries for invalid devices */
+			cqr->retries = -1;
+			DBF_DEV_EVENT(DBF_ERR, device, "%s",
+				      "EINVAL, handle as terminated");
+			/* fake rc to success */
+			rc = 0;
+			break;
+		case -EBUSY:
+			DBF_DEV_EVENT(DBF_ERR, device, "%s",
+				      "device busy, retry later");
+			break;
+		default:
+			/* internal error 10 - unknown rc*/
+			snprintf(errorstring, ERRORLENGTH, "10 %d", rc);
+			dev_err(&device->cdev->dev, "An error occurred in the "
+				"DASD device driver, reason=%s\n", errorstring);
+			BUG();
+			break;
+		}
+		retries++;
+	}
+	dasd_schedule_device_bh(device);
+	return rc;
+}
+EXPORT_SYMBOL(dasd_term_IO);
+
+/*
+ * Start the i/o. This start_IO can fail if the channel is really busy.
+ * In that case set up a timer to start the request later.
+ */
+int dasd_start_IO(struct dasd_ccw_req *cqr)
+{
+	struct dasd_device *device;
+	int rc;
+	char errorstring[ERRORLENGTH];
+
+	/* Check the cqr */
+	rc = dasd_check_cqr(cqr);
+	if (rc) {
+		cqr->intrc = rc;
+		return rc;
+	}
+	device = (struct dasd_device *) cqr->startdev;
+	if (((cqr->block &&
+	      test_bit(DASD_FLAG_LOCK_STOLEN, &cqr->block->base->flags)) ||
+	     test_bit(DASD_FLAG_LOCK_STOLEN, &device->flags)) &&
+	    !test_bit(DASD_CQR_ALLOW_SLOCK, &cqr->flags)) {
+		DBF_DEV_EVENT(DBF_DEBUG, device, "start_IO: return request %p "
+			      "because of stolen lock", cqr);
+		cqr->status = DASD_CQR_ERROR;
+		cqr->intrc = -EPERM;
+		return -EPERM;
+	}
+	if (cqr->retries < 0) {
+		/* internal error 14 - start_IO run out of retries */
+		sprintf(errorstring, "14 %p", cqr);
+		dev_err(&device->cdev->dev, "An error occurred in the DASD "
+			"device driver, reason=%s\n", errorstring);
+		cqr->status = DASD_CQR_ERROR;
+		return -EIO;
+	}
+	cqr->startclk = get_tod_clock();
+	cqr->starttime = jiffies;
+	cqr->retries--;
+	if (!test_bit(DASD_CQR_VERIFY_PATH, &cqr->flags)) {
+		cqr->lpm &= device->path_data.opm;
+		if (!cqr->lpm)
+			cqr->lpm = device->path_data.opm;
+	}
+	if (cqr->cpmode == 1) {
+		rc = ccw_device_tm_start(device->cdev, cqr->cpaddr,
+					 (long) cqr, cqr->lpm);
+	} else {
+		rc = ccw_device_start(device->cdev, cqr->cpaddr,
+				      (long) cqr, cqr->lpm, 0);
+	}
+	switch (rc) {
+	case 0:
+		cqr->status = DASD_CQR_IN_IO;
+		break;
+	case -EBUSY:
+		DBF_DEV_EVENT(DBF_WARNING, device, "%s",
+			      "start_IO: device busy, retry later");
+		break;
+	case -ETIMEDOUT:
+		DBF_DEV_EVENT(DBF_WARNING, device, "%s",
+			      "start_IO: request timeout, retry later");
+		break;
+	case -EACCES:
+		/* -EACCES indicates that the request used only a subset of the
+		 * available paths and all these paths are gone. If the lpm of
+		 * this request was only a subset of the opm (e.g. the ppm) then
+		 * we just do a retry with all available paths.
+		 * If we already use the full opm, something is amiss, and we
+		 * need a full path verification.
+		 */
+		if (test_bit(DASD_CQR_VERIFY_PATH, &cqr->flags)) {
+			DBF_DEV_EVENT(DBF_WARNING, device,
+				      "start_IO: selected paths gone (%x)",
+				      cqr->lpm);
+		} else if (cqr->lpm != device->path_data.opm) {
+			cqr->lpm = device->path_data.opm;
+			DBF_DEV_EVENT(DBF_DEBUG, device, "%s",
+				      "start_IO: selected paths gone,"
+				      " retry on all paths");
+		} else {
+			DBF_DEV_EVENT(DBF_WARNING, device, "%s",
+				      "start_IO: all paths in opm gone,"
+				      " do path verification");
+			dasd_generic_last_path_gone(device);
+			device->path_data.opm = 0;
+			device->path_data.ppm = 0;
+			device->path_data.npm = 0;
+			device->path_data.tbvpm =
+				ccw_device_get_path_mask(device->cdev);
+		}
+		break;
+	case -ENODEV:
+		DBF_DEV_EVENT(DBF_WARNING, device, "%s",
+			      "start_IO: -ENODEV device gone, retry");
+		break;
+	case -EIO:
+		DBF_DEV_EVENT(DBF_WARNING, device, "%s",
+			      "start_IO: -EIO device gone, retry");
+		break;
+	case -EINVAL:
+		/* most likely caused in power management context */
+		DBF_DEV_EVENT(DBF_WARNING, device, "%s",
+			      "start_IO: -EINVAL device currently "
+			      "not accessible");
+		break;
+	default:
+		/* internal error 11 - unknown rc */
+		snprintf(errorstring, ERRORLENGTH, "11 %d", rc);
+		dev_err(&device->cdev->dev,
+			"An error occurred in the DASD device driver, "
+			"reason=%s\n", errorstring);
+		BUG();
+		break;
+	}
+	cqr->intrc = rc;
+	return rc;
+}
+EXPORT_SYMBOL(dasd_start_IO);
+
+/*
+ * Timeout function for dasd devices. This is used for different purposes
+ *  1) missing interrupt handler for normal operation
+ *  2) delayed start of request where start_IO failed with -EBUSY
+ *  3) timeout for missing state change interrupts
+ * The head of the ccw queue will have status DASD_CQR_IN_IO for 1),
+ * DASD_CQR_QUEUED for 2) and 3).
+ */
+static void dasd_device_timeout(unsigned long ptr)
+{
+	unsigned long flags;
+	struct dasd_device *device;
+
+	device = (struct dasd_device *) ptr;
+	spin_lock_irqsave(get_ccwdev_lock(device->cdev), flags);
+	/* re-activate request queue */
+	dasd_device_remove_stop_bits(device, DASD_STOPPED_PENDING);
+	spin_unlock_irqrestore(get_ccwdev_lock(device->cdev), flags);
+	dasd_schedule_device_bh(device);
+}
+
+/*
+ * Setup timeout for a device in jiffies.
+ */
+void dasd_device_set_timer(struct dasd_device *device, int expires)
+{
+	if (expires == 0)
+		del_timer(&device->timer);
+	else
+		mod_timer(&device->timer, jiffies + expires);
+}
+EXPORT_SYMBOL(dasd_device_set_timer);
+
+/*
+ * Clear timeout for a device.
+ */
+void dasd_device_clear_timer(struct dasd_device *device)
+{
+	del_timer(&device->timer);
+}
+EXPORT_SYMBOL(dasd_device_clear_timer);
+
+static void dasd_handle_killed_request(struct ccw_device *cdev,
+				       unsigned long intparm)
+{
+	struct dasd_ccw_req *cqr;
+	struct dasd_device *device;
+
+	if (!intparm)
+		return;
+	cqr = (struct dasd_ccw_req *) intparm;
+	if (cqr->status != DASD_CQR_IN_IO) {
+		DBF_EVENT_DEVID(DBF_DEBUG, cdev,
+				"invalid status in handle_killed_request: "
+				"%02x", cqr->status);
+		return;
+	}
+
+	device = dasd_device_from_cdev_locked(cdev);
+	if (IS_ERR(device)) {
+		DBF_EVENT_DEVID(DBF_DEBUG, cdev, "%s",
+				"unable to get device from cdev");
+		return;
+	}
+
+	if (!cqr->startdev ||
+	    device != cqr->startdev ||
+	    strncmp(cqr->startdev->discipline->ebcname,
+		    (char *) &cqr->magic, 4)) {
+		DBF_EVENT_DEVID(DBF_DEBUG, cdev, "%s",
+				"invalid device in request");
+		dasd_put_device(device);
+		return;
+	}
+
+	/* Schedule request to be retried. */
+	cqr->status = DASD_CQR_QUEUED;
+
+	dasd_device_clear_timer(device);
+	dasd_schedule_device_bh(device);
+	dasd_put_device(device);
+}
+
+void dasd_generic_handle_state_change(struct dasd_device *device)
+{
+	/* First of all start sense subsystem status request. */
+	dasd_eer_snss(device);
+
+	dasd_device_remove_stop_bits(device, DASD_STOPPED_PENDING);
+	dasd_schedule_device_bh(device);
+	if (device->block)
+		dasd_schedule_block_bh(device->block);
+}
+EXPORT_SYMBOL_GPL(dasd_generic_handle_state_change);
+
+/*
+ * Interrupt handler for "normal" ssch-io based dasd devices.
+ */
+void dasd_int_handler(struct ccw_device *cdev, unsigned long intparm,
+		      struct irb *irb)
+{
+	struct dasd_ccw_req *cqr, *next;
+	struct dasd_device *device;
+	unsigned long long now;
+	int expires;
+
+	if (IS_ERR(irb)) {
+		switch (PTR_ERR(irb)) {
+		case -EIO:
+			break;
+		case -ETIMEDOUT:
+			DBF_EVENT_DEVID(DBF_WARNING, cdev, "%s: "
+					"request timed out\n", __func__);
+			break;
+		default:
+			DBF_EVENT_DEVID(DBF_WARNING, cdev, "%s: "
+					"unknown error %ld\n", __func__,
+					PTR_ERR(irb));
+		}
+		dasd_handle_killed_request(cdev, intparm);
+		return;
+	}
+
+	now = get_tod_clock();
+	cqr = (struct dasd_ccw_req *) intparm;
+	/* check for conditions that should be handled immediately */
+	if (!cqr ||
+	    !(scsw_dstat(&irb->scsw) == (DEV_STAT_CHN_END | DEV_STAT_DEV_END) &&
+	      scsw_cstat(&irb->scsw) == 0)) {
+		if (cqr)
+			memcpy(&cqr->irb, irb, sizeof(*irb));
+		device = dasd_device_from_cdev_locked(cdev);
+		if (IS_ERR(device))
+			return;
+		/* ignore unsolicited interrupts for DIAG discipline */
+		if (device->discipline == dasd_diag_discipline_pointer) {
+			dasd_put_device(device);
+			return;
+		}
+		device->discipline->dump_sense_dbf(device, irb, "int");
+		if (device->features & DASD_FEATURE_ERPLOG)
+			device->discipline->dump_sense(device, cqr, irb);
+		device->discipline->check_for_device_change(device, cqr, irb);
+		dasd_put_device(device);
+	}
+
+	/* check for for attention message */
+	if (scsw_dstat(&irb->scsw) & DEV_STAT_ATTENTION) {
+		device = dasd_device_from_cdev_locked(cdev);
+		device->discipline->check_attention(device, irb->esw.esw1.lpum);
+		dasd_put_device(device);
+	}
+
+	if (!cqr)
+		return;
+
+	device = (struct dasd_device *) cqr->startdev;
+	if (!device ||
+	    strncmp(device->discipline->ebcname, (char *) &cqr->magic, 4)) {
+		DBF_EVENT_DEVID(DBF_DEBUG, cdev, "%s",
+				"invalid device in request");
+		return;
+	}
+
+	/* Check for clear pending */
+	if (cqr->status == DASD_CQR_CLEAR_PENDING &&
+	    scsw_fctl(&irb->scsw) & SCSW_FCTL_CLEAR_FUNC) {
+		cqr->status = DASD_CQR_CLEARED;
+		dasd_device_clear_timer(device);
+		wake_up(&dasd_flush_wq);
+		dasd_schedule_device_bh(device);
+		return;
+	}
+
+	/* check status - the request might have been killed by dyn detach */
+	if (cqr->status != DASD_CQR_IN_IO) {
+		DBF_DEV_EVENT(DBF_DEBUG, device, "invalid status: bus_id %s, "
+			      "status %02x", dev_name(&cdev->dev), cqr->status);
+		return;
+	}
+
+	next = NULL;
+	expires = 0;
+	if (scsw_dstat(&irb->scsw) == (DEV_STAT_CHN_END | DEV_STAT_DEV_END) &&
+	    scsw_cstat(&irb->scsw) == 0) {
+		/* request was completed successfully */
+		cqr->status = DASD_CQR_SUCCESS;
+		cqr->stopclk = now;
+		/* Start first request on queue if possible -> fast_io. */
+		if (cqr->devlist.next != &device->ccw_queue) {
+			next = list_entry(cqr->devlist.next,
+					  struct dasd_ccw_req, devlist);
+		}
+	} else {  /* error */
+		/*
+		 * If we don't want complex ERP for this request, then just
+		 * reset this and retry it in the fastpath
+		 */
+		if (!test_bit(DASD_CQR_FLAGS_USE_ERP, &cqr->flags) &&
+		    cqr->retries > 0) {
+			if (cqr->lpm == device->path_data.opm)
+				DBF_DEV_EVENT(DBF_DEBUG, device,
+					      "default ERP in fastpath "
+					      "(%i retries left)",
+					      cqr->retries);
+			if (!test_bit(DASD_CQR_VERIFY_PATH, &cqr->flags))
+				cqr->lpm = device->path_data.opm;
+			cqr->status = DASD_CQR_QUEUED;
+			next = cqr;
+		} else
+			cqr->status = DASD_CQR_ERROR;
+	}
+	if (next && (next->status == DASD_CQR_QUEUED) &&
+	    (!device->stopped)) {
+		if (device->discipline->start_IO(next) == 0)
+			expires = next->expires;
+	}
+	if (expires != 0)
+		dasd_device_set_timer(device, expires);
+	else
+		dasd_device_clear_timer(device);
+	dasd_schedule_device_bh(device);
+}
+EXPORT_SYMBOL(dasd_int_handler);
+
+enum uc_todo dasd_generic_uc_handler(struct ccw_device *cdev, struct irb *irb)
+{
+	struct dasd_device *device;
+
+	device = dasd_device_from_cdev_locked(cdev);
+
+	if (IS_ERR(device))
+		goto out;
+	if (test_bit(DASD_FLAG_OFFLINE, &device->flags) ||
+	   device->state != device->target ||
+	   !device->discipline->check_for_device_change){
+		dasd_put_device(device);
+		goto out;
+	}
+	if (device->discipline->dump_sense_dbf)
+		device->discipline->dump_sense_dbf(device, irb, "uc");
+	device->discipline->check_for_device_change(device, NULL, irb);
+	dasd_put_device(device);
+out:
+	return UC_TODO_RETRY;
+}
+EXPORT_SYMBOL_GPL(dasd_generic_uc_handler);
+
+/*
+ * If we have an error on a dasd_block layer request then we cancel
+ * and return all further requests from the same dasd_block as well.
+ */
+static void __dasd_device_recovery(struct dasd_device *device,
+				   struct dasd_ccw_req *ref_cqr)
+{
+	struct list_head *l, *n;
+	struct dasd_ccw_req *cqr;
+
+	/*
+	 * only requeue request that came from the dasd_block layer
+	 */
+	if (!ref_cqr->block)
+		return;
+
+	list_for_each_safe(l, n, &device->ccw_queue) {
+		cqr = list_entry(l, struct dasd_ccw_req, devlist);
+		if (cqr->status == DASD_CQR_QUEUED &&
+		    ref_cqr->block == cqr->block) {
+			cqr->status = DASD_CQR_CLEARED;
+		}
+	}
+};
+
+/*
+ * Remove those ccw requests from the queue that need to be returned
+ * to the upper layer.
+ */
+static void __dasd_device_process_ccw_queue(struct dasd_device *device,
+					    struct list_head *final_queue)
+{
+	struct list_head *l, *n;
+	struct dasd_ccw_req *cqr;
+
+	/* Process request with final status. */
+	list_for_each_safe(l, n, &device->ccw_queue) {
+		cqr = list_entry(l, struct dasd_ccw_req, devlist);
+
+		/* Skip any non-final request. */
+		if (cqr->status == DASD_CQR_QUEUED ||
+		    cqr->status == DASD_CQR_IN_IO ||
+		    cqr->status == DASD_CQR_CLEAR_PENDING)
+			continue;
+		if (cqr->status == DASD_CQR_ERROR) {
+			__dasd_device_recovery(device, cqr);
+		}
+		/* Rechain finished requests to final queue */
+		list_move_tail(&cqr->devlist, final_queue);
+	}
+}
+
+/*
+ * the cqrs from the final queue are returned to the upper layer
+ * by setting a dasd_block state and calling the callback function
+ */
+static void __dasd_device_process_final_queue(struct dasd_device *device,
+					      struct list_head *final_queue)
+{
+	struct list_head *l, *n;
+	struct dasd_ccw_req *cqr;
+	struct dasd_block *block;
+	void (*callback)(struct dasd_ccw_req *, void *data);
+	void *callback_data;
+	char errorstring[ERRORLENGTH];
+
+	list_for_each_safe(l, n, final_queue) {
+		cqr = list_entry(l, struct dasd_ccw_req, devlist);
+		list_del_init(&cqr->devlist);
+		block = cqr->block;
+		callback = cqr->callback;
+		callback_data = cqr->callback_data;
+		if (block)
+			spin_lock_bh(&block->queue_lock);
+		switch (cqr->status) {
+		case DASD_CQR_SUCCESS:
+			cqr->status = DASD_CQR_DONE;
+			break;
+		case DASD_CQR_ERROR:
+			cqr->status = DASD_CQR_NEED_ERP;
+			break;
+		case DASD_CQR_CLEARED:
+			cqr->status = DASD_CQR_TERMINATED;
+			break;
+		default:
+			/* internal error 12 - wrong cqr status*/
+			snprintf(errorstring, ERRORLENGTH, "12 %p %x02", cqr, cqr->status);
+			dev_err(&device->cdev->dev,
+				"An error occurred in the DASD device driver, "
+				"reason=%s\n", errorstring);
+			BUG();
+		}
+		if (cqr->callback != NULL)
+			(callback)(cqr, callback_data);
+		if (block)
+			spin_unlock_bh(&block->queue_lock);
+	}
+}
+
+/*
+ * Take a look at the first request on the ccw queue and check
+ * if it reached its expire time. If so, terminate the IO.
+ */
+static void __dasd_device_check_expire(struct dasd_device *device)
+{
+	struct dasd_ccw_req *cqr;
+
+	if (list_empty(&device->ccw_queue))
+		return;
+	cqr = list_entry(device->ccw_queue.next, struct dasd_ccw_req, devlist);
+	if ((cqr->status == DASD_CQR_IN_IO && cqr->expires != 0) &&
+	    (time_after_eq(jiffies, cqr->expires + cqr->starttime))) {
+		if (test_bit(DASD_FLAG_SAFE_OFFLINE_RUNNING, &device->flags)) {
+			/*
+			 * IO in safe offline processing should not
+			 * run out of retries
+			 */
+			cqr->retries++;
+		}
+		if (device->discipline->term_IO(cqr) != 0) {
+			/* Hmpf, try again in 5 sec */
+			dev_err(&device->cdev->dev,
+				"cqr %p timed out (%lus) but cannot be "
+				"ended, retrying in 5 s\n",
+				cqr, (cqr->expires/HZ));
+			cqr->expires += 5*HZ;
+			dasd_device_set_timer(device, 5*HZ);
+		} else {
+			dev_err(&device->cdev->dev,
+				"cqr %p timed out (%lus), %i retries "
+				"remaining\n", cqr, (cqr->expires/HZ),
+				cqr->retries);
+		}
+	}
+}
+
+/*
+ * Take a look at the first request on the ccw queue and check
+ * if it needs to be started.
+ */
+static void __dasd_device_start_head(struct dasd_device *device)
+{
+	struct dasd_ccw_req *cqr;
+	int rc;
+
+	if (list_empty(&device->ccw_queue))
+		return;
+	cqr = list_entry(device->ccw_queue.next, struct dasd_ccw_req, devlist);
+	if (cqr->status != DASD_CQR_QUEUED)
+		return;
+	/* when device is stopped, return request to previous layer
+	 * exception: only the disconnect or unresumed bits are set and the
+	 * cqr is a path verification request
+	 */
+	if (device->stopped &&
+	    !(!(device->stopped & ~(DASD_STOPPED_DC_WAIT | DASD_UNRESUMED_PM))
+	      && test_bit(DASD_CQR_VERIFY_PATH, &cqr->flags))) {
+		cqr->intrc = -EAGAIN;
+		cqr->status = DASD_CQR_CLEARED;
+		dasd_schedule_device_bh(device);
+		return;
+	}
+
+	rc = device->discipline->start_IO(cqr);
+	if (rc == 0)
+		dasd_device_set_timer(device, cqr->expires);
+	else if (rc == -EACCES) {
+		dasd_schedule_device_bh(device);
+	} else
+		/* Hmpf, try again in 1/2 sec */
+		dasd_device_set_timer(device, 50);
+}
+
+static void __dasd_device_check_path_events(struct dasd_device *device)
+{
+	int rc;
+
+	if (device->path_data.tbvpm) {
+		if (device->stopped & ~(DASD_STOPPED_DC_WAIT |
+					DASD_UNRESUMED_PM))
+			return;
+		rc = device->discipline->verify_path(
+			device, device->path_data.tbvpm);
+		if (rc)
+			dasd_device_set_timer(device, 50);
+		else
+			device->path_data.tbvpm = 0;
+	}
+};
+
+/*
+ * Go through all request on the dasd_device request queue,
+ * terminate them on the cdev if necessary, and return them to the
+ * submitting layer via callback.
+ * Note:
+ * Make sure that all 'submitting layers' still exist when
+ * this function is called!. In other words, when 'device' is a base
+ * device then all block layer requests must have been removed before
+ * via dasd_flush_block_queue.
+ */
+int dasd_flush_device_queue(struct dasd_device *device)
+{
+	struct dasd_ccw_req *cqr, *n;
+	int rc;
+	struct list_head flush_queue;
+
+	INIT_LIST_HEAD(&flush_queue);
+	spin_lock_irq(get_ccwdev_lock(device->cdev));
+	rc = 0;
+	list_for_each_entry_safe(cqr, n, &device->ccw_queue, devlist) {
+		/* Check status and move request to flush_queue */
+		switch (cqr->status) {
+		case DASD_CQR_IN_IO:
+			rc = device->discipline->term_IO(cqr);
+			if (rc) {
+				/* unable to terminate requeust */
+				dev_err(&device->cdev->dev,
+					"Flushing the DASD request queue "
+					"failed for request %p\n", cqr);
+				/* stop flush processing */
+				goto finished;
+			}
+			break;
+		case DASD_CQR_QUEUED:
+			cqr->stopclk = get_tod_clock();
+			cqr->status = DASD_CQR_CLEARED;
+			break;
+		default: /* no need to modify the others */
+			break;
+		}
+		list_move_tail(&cqr->devlist, &flush_queue);
+	}
+finished:
+	spin_unlock_irq(get_ccwdev_lock(device->cdev));
+	/*
+	 * After this point all requests must be in state CLEAR_PENDING,
+	 * CLEARED, SUCCESS or ERROR. Now wait for CLEAR_PENDING to become
+	 * one of the others.
+	 */
+	list_for_each_entry_safe(cqr, n, &flush_queue, devlist)
+		wait_event(dasd_flush_wq,
+			   (cqr->status != DASD_CQR_CLEAR_PENDING));
+	/*
+	 * Now set each request back to TERMINATED, DONE or NEED_ERP
+	 * and call the callback function of flushed requests
+	 */
+	__dasd_device_process_final_queue(device, &flush_queue);
+	return rc;
+}
+EXPORT_SYMBOL_GPL(dasd_flush_device_queue);
+
+/*
+ * Acquire the device lock and process queues for the device.
+ */
+static void dasd_device_tasklet(struct dasd_device *device)
+{
+	struct list_head final_queue;
+
+	atomic_set (&device->tasklet_scheduled, 0);
+	INIT_LIST_HEAD(&final_queue);
+	spin_lock_irq(get_ccwdev_lock(device->cdev));
+	/* Check expire time of first request on the ccw queue. */
+	__dasd_device_check_expire(device);
+	/* find final requests on ccw queue */
+	__dasd_device_process_ccw_queue(device, &final_queue);
+	__dasd_device_check_path_events(device);
+	spin_unlock_irq(get_ccwdev_lock(device->cdev));
+	/* Now call the callback function of requests with final status */
+	__dasd_device_process_final_queue(device, &final_queue);
+	spin_lock_irq(get_ccwdev_lock(device->cdev));
+	/* Now check if the head of the ccw queue needs to be started. */
+	__dasd_device_start_head(device);
+	spin_unlock_irq(get_ccwdev_lock(device->cdev));
+	if (waitqueue_active(&shutdown_waitq))
+		wake_up(&shutdown_waitq);
+	dasd_put_device(device);
+}
+
+/*
+ * Schedules a call to dasd_tasklet over the device tasklet.
+ */
+void dasd_schedule_device_bh(struct dasd_device *device)
+{
+	/* Protect against rescheduling. */
+	if (atomic_cmpxchg (&device->tasklet_scheduled, 0, 1) != 0)
+		return;
+	dasd_get_device(device);
+	tasklet_hi_schedule(&device->tasklet);
+}
+EXPORT_SYMBOL(dasd_schedule_device_bh);
+
+void dasd_device_set_stop_bits(struct dasd_device *device, int bits)
+{
+	device->stopped |= bits;
+}
+EXPORT_SYMBOL_GPL(dasd_device_set_stop_bits);
+
+void dasd_device_remove_stop_bits(struct dasd_device *device, int bits)
+{
+	device->stopped &= ~bits;
+	if (!device->stopped)
+		wake_up(&generic_waitq);
+}
+EXPORT_SYMBOL_GPL(dasd_device_remove_stop_bits);
+
+/*
+ * Queue a request to the head of the device ccw_queue.
+ * Start the I/O if possible.
+ */
+void dasd_add_request_head(struct dasd_ccw_req *cqr)
+{
+	struct dasd_device *device;
+	unsigned long flags;
+
+	device = cqr->startdev;
+	spin_lock_irqsave(get_ccwdev_lock(device->cdev), flags);
+	cqr->status = DASD_CQR_QUEUED;
+	list_add(&cqr->devlist, &device->ccw_queue);
+	/* let the bh start the request to keep them in order */
+	dasd_schedule_device_bh(device);
+	spin_unlock_irqrestore(get_ccwdev_lock(device->cdev), flags);
+}
+EXPORT_SYMBOL(dasd_add_request_head);
+
+/*
+ * Queue a request to the tail of the device ccw_queue.
+ * Start the I/O if possible.
+ */
+void dasd_add_request_tail(struct dasd_ccw_req *cqr)
+{
+	struct dasd_device *device;
+	unsigned long flags;
+
+	device = cqr->startdev;
+	spin_lock_irqsave(get_ccwdev_lock(device->cdev), flags);
+	cqr->status = DASD_CQR_QUEUED;
+	list_add_tail(&cqr->devlist, &device->ccw_queue);
+	/* let the bh start the request to keep them in order */
+	dasd_schedule_device_bh(device);
+	spin_unlock_irqrestore(get_ccwdev_lock(device->cdev), flags);
+}
+EXPORT_SYMBOL(dasd_add_request_tail);
+
+/*
+ * Wakeup helper for the 'sleep_on' functions.
+ */
+void dasd_wakeup_cb(struct dasd_ccw_req *cqr, void *data)
+{
+	spin_lock_irq(get_ccwdev_lock(cqr->startdev->cdev));
+	cqr->callback_data = DASD_SLEEPON_END_TAG;
+	spin_unlock_irq(get_ccwdev_lock(cqr->startdev->cdev));
+	wake_up(&generic_waitq);
+}
+EXPORT_SYMBOL_GPL(dasd_wakeup_cb);
+
+static inline int _wait_for_wakeup(struct dasd_ccw_req *cqr)
+{
+	struct dasd_device *device;
+	int rc;
+
+	device = cqr->startdev;
+	spin_lock_irq(get_ccwdev_lock(device->cdev));
+	rc = (cqr->callback_data == DASD_SLEEPON_END_TAG);
+	spin_unlock_irq(get_ccwdev_lock(device->cdev));
+	return rc;
+}
+
+/*
+ * checks if error recovery is necessary, returns 1 if yes, 0 otherwise.
+ */
+static int __dasd_sleep_on_erp(struct dasd_ccw_req *cqr)
+{
+	struct dasd_device *device;
+	dasd_erp_fn_t erp_fn;
+
+	if (cqr->status == DASD_CQR_FILLED)
+		return 0;
+	device = cqr->startdev;
+	if (test_bit(DASD_CQR_FLAGS_USE_ERP, &cqr->flags)) {
+		if (cqr->status == DASD_CQR_TERMINATED) {
+			device->discipline->handle_terminated_request(cqr);
+			return 1;
+		}
+		if (cqr->status == DASD_CQR_NEED_ERP) {
+			erp_fn = device->discipline->erp_action(cqr);
+			erp_fn(cqr);
+			return 1;
+		}
+		if (cqr->status == DASD_CQR_FAILED)
+			dasd_log_sense(cqr, &cqr->irb);
+		if (cqr->refers) {
+			__dasd_process_erp(device, cqr);
+			return 1;
+		}
+	}
+	return 0;
+}
+
+static int __dasd_sleep_on_loop_condition(struct dasd_ccw_req *cqr)
+{
+	if (test_bit(DASD_CQR_FLAGS_USE_ERP, &cqr->flags)) {
+		if (cqr->refers) /* erp is not done yet */
+			return 1;
+		return ((cqr->status != DASD_CQR_DONE) &&
+			(cqr->status != DASD_CQR_FAILED));
+	} else
+		return (cqr->status == DASD_CQR_FILLED);
+}
+
+static int _dasd_sleep_on(struct dasd_ccw_req *maincqr, int interruptible)
+{
+	struct dasd_device *device;
+	int rc;
+	struct list_head ccw_queue;
+	struct dasd_ccw_req *cqr;
+
+	INIT_LIST_HEAD(&ccw_queue);
+	maincqr->status = DASD_CQR_FILLED;
+	device = maincqr->startdev;
+	list_add(&maincqr->blocklist, &ccw_queue);
+	for (cqr = maincqr;  __dasd_sleep_on_loop_condition(cqr);
+	     cqr = list_first_entry(&ccw_queue,
+				    struct dasd_ccw_req, blocklist)) {
+
+		if (__dasd_sleep_on_erp(cqr))
+			continue;
+		if (cqr->status != DASD_CQR_FILLED) /* could be failed */
+			continue;
+		if (test_bit(DASD_FLAG_LOCK_STOLEN, &device->flags) &&
+		    !test_bit(DASD_CQR_ALLOW_SLOCK, &cqr->flags)) {
+			cqr->status = DASD_CQR_FAILED;
+			cqr->intrc = -EPERM;
+			continue;
+		}
+		/* Non-temporary stop condition will trigger fail fast */
+		if (device->stopped & ~DASD_STOPPED_PENDING &&
+		    test_bit(DASD_CQR_FLAGS_FAILFAST, &cqr->flags) &&
+		    (!dasd_eer_enabled(device))) {
+			cqr->status = DASD_CQR_FAILED;
+			cqr->intrc = -ENOLINK;
+			continue;
+		}
+		/*
+		 * Don't try to start requests if device is stopped
+		 * except path verification requests
+		 */
+		if (!test_bit(DASD_CQR_VERIFY_PATH, &cqr->flags)) {
+			if (interruptible) {
+				rc = wait_event_interruptible(
+					generic_waitq, !(device->stopped));
+				if (rc == -ERESTARTSYS) {
+					cqr->status = DASD_CQR_FAILED;
+					maincqr->intrc = rc;
+					continue;
+				}
+			} else
+				wait_event(generic_waitq, !(device->stopped));
+		}
+		if (!cqr->callback)
+			cqr->callback = dasd_wakeup_cb;
+
+		cqr->callback_data = DASD_SLEEPON_START_TAG;
+		dasd_add_request_tail(cqr);
+		if (interruptible) {
+			rc = wait_event_interruptible(
+				generic_waitq, _wait_for_wakeup(cqr));
+			if (rc == -ERESTARTSYS) {
+				dasd_cancel_req(cqr);
+				/* wait (non-interruptible) for final status */
+				wait_event(generic_waitq,
+					   _wait_for_wakeup(cqr));
+				cqr->status = DASD_CQR_FAILED;
+				maincqr->intrc = rc;
+				continue;
+			}
+		} else
+			wait_event(generic_waitq, _wait_for_wakeup(cqr));
+	}
+
+	maincqr->endclk = get_tod_clock();
+	if ((maincqr->status != DASD_CQR_DONE) &&
+	    (maincqr->intrc != -ERESTARTSYS))
+		dasd_log_sense(maincqr, &maincqr->irb);
+	if (maincqr->status == DASD_CQR_DONE)
+		rc = 0;
+	else if (maincqr->intrc)
+		rc = maincqr->intrc;
+	else
+		rc = -EIO;
+	return rc;
+}
+
+static inline int _wait_for_wakeup_queue(struct list_head *ccw_queue)
+{
+	struct dasd_ccw_req *cqr;
+
+	list_for_each_entry(cqr, ccw_queue, blocklist) {
+		if (cqr->callback_data != DASD_SLEEPON_END_TAG)
+			return 0;
+	}
+
+	return 1;
+}
+
+static int _dasd_sleep_on_queue(struct list_head *ccw_queue, int interruptible)
+{
+	struct dasd_device *device;
+	struct dasd_ccw_req *cqr, *n;
+	int rc;
+
+retry:
+	list_for_each_entry_safe(cqr, n, ccw_queue, blocklist) {
+		device = cqr->startdev;
+		if (cqr->status != DASD_CQR_FILLED) /*could be failed*/
+			continue;
+
+		if (test_bit(DASD_FLAG_LOCK_STOLEN, &device->flags) &&
+		    !test_bit(DASD_CQR_ALLOW_SLOCK, &cqr->flags)) {
+			cqr->status = DASD_CQR_FAILED;
+			cqr->intrc = -EPERM;
+			continue;
+		}
+		/*Non-temporary stop condition will trigger fail fast*/
+		if (device->stopped & ~DASD_STOPPED_PENDING &&
+		    test_bit(DASD_CQR_FLAGS_FAILFAST, &cqr->flags) &&
+		    !dasd_eer_enabled(device)) {
+			cqr->status = DASD_CQR_FAILED;
+			cqr->intrc = -EAGAIN;
+			continue;
+		}
+
+		/*Don't try to start requests if device is stopped*/
+		if (interruptible) {
+			rc = wait_event_interruptible(
+				generic_waitq, !device->stopped);
+			if (rc == -ERESTARTSYS) {
+				cqr->status = DASD_CQR_FAILED;
+				cqr->intrc = rc;
+				continue;
+			}
+		} else
+			wait_event(generic_waitq, !(device->stopped));
+
+		if (!cqr->callback)
+			cqr->callback = dasd_wakeup_cb;
+		cqr->callback_data = DASD_SLEEPON_START_TAG;
+		dasd_add_request_tail(cqr);
+	}
+
+	wait_event(generic_waitq, _wait_for_wakeup_queue(ccw_queue));
+
+	rc = 0;
+	list_for_each_entry_safe(cqr, n, ccw_queue, blocklist) {
+		/*
+		 * for alias devices simplify error recovery and
+		 * return to upper layer
+		 * do not skip ERP requests
+		 */
+		if (cqr->startdev != cqr->basedev && !cqr->refers &&
+		    (cqr->status == DASD_CQR_TERMINATED ||
+		     cqr->status == DASD_CQR_NEED_ERP))
+			return -EAGAIN;
+
+		/* normal recovery for basedev IO */
+		if (__dasd_sleep_on_erp(cqr))
+			/* handle erp first */
+			goto retry;
+	}
+
+	return 0;
+}
+
+/*
+ * Queue a request to the tail of the device ccw_queue and wait for
+ * it's completion.
+ */
+int dasd_sleep_on(struct dasd_ccw_req *cqr)
+{
+	return _dasd_sleep_on(cqr, 0);
+}
+EXPORT_SYMBOL(dasd_sleep_on);
+
+/*
+ * Start requests from a ccw_queue and wait for their completion.
+ */
+int dasd_sleep_on_queue(struct list_head *ccw_queue)
+{
+	return _dasd_sleep_on_queue(ccw_queue, 0);
+}
+EXPORT_SYMBOL(dasd_sleep_on_queue);
+
+/*
+ * Queue a request to the tail of the device ccw_queue and wait
+ * interruptible for it's completion.
+ */
+int dasd_sleep_on_interruptible(struct dasd_ccw_req *cqr)
+{
+	return _dasd_sleep_on(cqr, 1);
+}
+EXPORT_SYMBOL(dasd_sleep_on_interruptible);
+
+/*
+ * Whoa nelly now it gets really hairy. For some functions (e.g. steal lock
+ * for eckd devices) the currently running request has to be terminated
+ * and be put back to status queued, before the special request is added
+ * to the head of the queue. Then the special request is waited on normally.
+ */
+static inline int _dasd_term_running_cqr(struct dasd_device *device)
+{
+	struct dasd_ccw_req *cqr;
+	int rc;
+
+	if (list_empty(&device->ccw_queue))
+		return 0;
+	cqr = list_entry(device->ccw_queue.next, struct dasd_ccw_req, devlist);
+	rc = device->discipline->term_IO(cqr);
+	if (!rc)
+		/*
+		 * CQR terminated because a more important request is pending.
+		 * Undo decreasing of retry counter because this is
+		 * not an error case.
+		 */
+		cqr->retries++;
+	return rc;
+}
+
+int dasd_sleep_on_immediatly(struct dasd_ccw_req *cqr)
+{
+	struct dasd_device *device;
+	int rc;
+
+	device = cqr->startdev;
+	if (test_bit(DASD_FLAG_LOCK_STOLEN, &device->flags) &&
+	    !test_bit(DASD_CQR_ALLOW_SLOCK, &cqr->flags)) {
+		cqr->status = DASD_CQR_FAILED;
+		cqr->intrc = -EPERM;
+		return -EIO;
+	}
+	spin_lock_irq(get_ccwdev_lock(device->cdev));
+	rc = _dasd_term_running_cqr(device);
+	if (rc) {
+		spin_unlock_irq(get_ccwdev_lock(device->cdev));
+		return rc;
+	}
+	cqr->callback = dasd_wakeup_cb;
+	cqr->callback_data = DASD_SLEEPON_START_TAG;
+	cqr->status = DASD_CQR_QUEUED;
+	/*
+	 * add new request as second
+	 * first the terminated cqr needs to be finished
+	 */
+	list_add(&cqr->devlist, device->ccw_queue.next);
+
+	/* let the bh start the request to keep them in order */
+	dasd_schedule_device_bh(device);
+
+	spin_unlock_irq(get_ccwdev_lock(device->cdev));
+
+	wait_event(generic_waitq, _wait_for_wakeup(cqr));
+
+	if (cqr->status == DASD_CQR_DONE)
+		rc = 0;
+	else if (cqr->intrc)
+		rc = cqr->intrc;
+	else
+		rc = -EIO;
+
+	/* kick tasklets */
+	dasd_schedule_device_bh(device);
+	if (device->block)
+		dasd_schedule_block_bh(device->block);
+
+	return rc;
+}
+EXPORT_SYMBOL(dasd_sleep_on_immediatly);
+
+/*
+ * Cancels a request that was started with dasd_sleep_on_req.
+ * This is useful to timeout requests. The request will be
+ * terminated if it is currently in i/o.
+ * Returns 0 if request termination was successful
+ *	   negative error code if termination failed
+ * Cancellation of a request is an asynchronous operation! The calling
+ * function has to wait until the request is properly returned via callback.
+ */
+int dasd_cancel_req(struct dasd_ccw_req *cqr)
+{
+	struct dasd_device *device = cqr->startdev;
+	unsigned long flags;
+	int rc;
+
+	rc = 0;
+	spin_lock_irqsave(get_ccwdev_lock(device->cdev), flags);
+	switch (cqr->status) {
+	case DASD_CQR_QUEUED:
+		/* request was not started - just set to cleared */
+		cqr->status = DASD_CQR_CLEARED;
+		if (cqr->callback_data == DASD_SLEEPON_START_TAG)
+			cqr->callback_data = DASD_SLEEPON_END_TAG;
+		break;
+	case DASD_CQR_IN_IO:
+		/* request in IO - terminate IO and release again */
+		rc = device->discipline->term_IO(cqr);
+		if (rc) {
+			dev_err(&device->cdev->dev,
+				"Cancelling request %p failed with rc=%d\n",
+				cqr, rc);
+		} else {
+			cqr->stopclk = get_tod_clock();
+		}
+		break;
+	default: /* already finished or clear pending - do nothing */
+		break;
+	}
+	spin_unlock_irqrestore(get_ccwdev_lock(device->cdev), flags);
+	dasd_schedule_device_bh(device);
+	return rc;
+}
+EXPORT_SYMBOL(dasd_cancel_req);
+
+/*
+ * SECTION: Operations of the dasd_block layer.
+ */
+
+/*
+ * Timeout function for dasd_block. This is used when the block layer
+ * is waiting for something that may not come reliably, (e.g. a state
+ * change interrupt)
+ */
+static void dasd_block_timeout(unsigned long ptr)
+{
+	unsigned long flags;
+	struct dasd_block *block;
+
+	block = (struct dasd_block *) ptr;
+	spin_lock_irqsave(get_ccwdev_lock(block->base->cdev), flags);
+	/* re-activate request queue */
+	dasd_device_remove_stop_bits(block->base, DASD_STOPPED_PENDING);
+	spin_unlock_irqrestore(get_ccwdev_lock(block->base->cdev), flags);
+	dasd_schedule_block_bh(block);
+}
+
+/*
+ * Setup timeout for a dasd_block in jiffies.
+ */
+void dasd_block_set_timer(struct dasd_block *block, int expires)
+{
+	if (expires == 0)
+		del_timer(&block->timer);
+	else
+		mod_timer(&block->timer, jiffies + expires);
+}
+EXPORT_SYMBOL(dasd_block_set_timer);
+
+/*
+ * Clear timeout for a dasd_block.
+ */
+void dasd_block_clear_timer(struct dasd_block *block)
+{
+	del_timer(&block->timer);
+}
+EXPORT_SYMBOL(dasd_block_clear_timer);
+
+/*
+ * Process finished error recovery ccw.
+ */
+static void __dasd_process_erp(struct dasd_device *device,
+			       struct dasd_ccw_req *cqr)
+{
+	dasd_erp_fn_t erp_fn;
+
+	if (cqr->status == DASD_CQR_DONE)
+		DBF_DEV_EVENT(DBF_NOTICE, device, "%s", "ERP successful");
+	else
+		dev_err(&device->cdev->dev, "ERP failed for the DASD\n");
+	erp_fn = device->discipline->erp_postaction(cqr);
+	erp_fn(cqr);
+}
+
+/*
+ * Fetch requests from the block device queue.
+ */
+static void __dasd_process_request_queue(struct dasd_block *block)
+{
+	struct request_queue *queue;
+	struct request *req;
+	struct dasd_ccw_req *cqr;
+	struct dasd_device *basedev;
+	unsigned long flags;
+	queue = block->request_queue;
+	basedev = block->base;
+	/* No queue ? Then there is nothing to do. */
+	if (queue == NULL)
+		return;
+
+	/*
+	 * We requeue request from the block device queue to the ccw
+	 * queue only in two states. In state DASD_STATE_READY the
+	 * partition detection is done and we need to requeue requests
+	 * for that. State DASD_STATE_ONLINE is normal block device
+	 * operation.
+	 */
+	if (basedev->state < DASD_STATE_READY) {
+		while ((req = blk_fetch_request(block->request_queue)))
+			__blk_end_request_all(req, -EIO);
+		return;
+	}
+
+	/* if device ist stopped do not fetch new requests */
+	if (basedev->stopped)
+		return;
+
+	/* Now we try to fetch requests from the request queue */
+	while ((req = blk_peek_request(queue))) {
+		if (basedev->features & DASD_FEATURE_READONLY &&
+		    rq_data_dir(req) == WRITE) {
+			DBF_DEV_EVENT(DBF_ERR, basedev,
+				      "Rejecting write request %p",
+				      req);
+			blk_start_request(req);
+			__blk_end_request_all(req, -EIO);
+			continue;
+		}
+		if (test_bit(DASD_FLAG_ABORTALL, &basedev->flags) &&
+		    (basedev->features & DASD_FEATURE_FAILFAST ||
+		     blk_noretry_request(req))) {
+			DBF_DEV_EVENT(DBF_ERR, basedev,
+				      "Rejecting failfast request %p",
+				      req);
+			blk_start_request(req);
+			__blk_end_request_all(req, -ETIMEDOUT);
+			continue;
+		}
+		cqr = basedev->discipline->build_cp(basedev, block, req);
+		if (IS_ERR(cqr)) {
+			if (PTR_ERR(cqr) == -EBUSY)
+				break;	/* normal end condition */
+			if (PTR_ERR(cqr) == -ENOMEM)
+				break;	/* terminate request queue loop */
+			if (PTR_ERR(cqr) == -EAGAIN) {
+				/*
+				 * The current request cannot be build right
+				 * now, we have to try later. If this request
+				 * is the head-of-queue we stop the device
+				 * for 1/2 second.
+				 */
+				if (!list_empty(&block->ccw_queue))
+					break;
+				spin_lock_irqsave(
+					get_ccwdev_lock(basedev->cdev), flags);
+				dasd_device_set_stop_bits(basedev,
+							  DASD_STOPPED_PENDING);
+				spin_unlock_irqrestore(
+					get_ccwdev_lock(basedev->cdev), flags);
+				dasd_block_set_timer(block, HZ/2);
+				break;
+			}
+			DBF_DEV_EVENT(DBF_ERR, basedev,
+				      "CCW creation failed (rc=%ld) "
+				      "on request %p",
+				      PTR_ERR(cqr), req);
+			blk_start_request(req);
+			__blk_end_request_all(req, -EIO);
+			continue;
+		}
+		/*
+		 *  Note: callback is set to dasd_return_cqr_cb in
+		 * __dasd_block_start_head to cover erp requests as well
+		 */
+		cqr->callback_data = (void *) req;
+		cqr->status = DASD_CQR_FILLED;
+		req->completion_data = cqr;
+		blk_start_request(req);
+		list_add_tail(&cqr->blocklist, &block->ccw_queue);
+		INIT_LIST_HEAD(&cqr->devlist);
+		dasd_profile_start(block, cqr, req);
+	}
+}
+
+static void __dasd_cleanup_cqr(struct dasd_ccw_req *cqr)
+{
+	struct request *req;
+	int status;
+	int error = 0;
+
+	req = (struct request *) cqr->callback_data;
+	dasd_profile_end(cqr->block, cqr, req);
+	status = cqr->block->base->discipline->free_cp(cqr, req);
+	if (status < 0)
+		error = status;
+	else if (status == 0) {
+		if (cqr->intrc == -EPERM)
+			error = -EBADE;
+		else if (cqr->intrc == -ENOLINK ||
+			 cqr->intrc == -ETIMEDOUT)
+			error = cqr->intrc;
+		else
+			error = -EIO;
+	}
+	__blk_end_request_all(req, error);
+}
+
+/*
+ * Process ccw request queue.
+ */
+static void __dasd_process_block_ccw_queue(struct dasd_block *block,
+					   struct list_head *final_queue)
+{
+	struct list_head *l, *n;
+	struct dasd_ccw_req *cqr;
+	dasd_erp_fn_t erp_fn;
+	unsigned long flags;
+	struct dasd_device *base = block->base;
+
+restart:
+	/* Process request with final status. */
+	list_for_each_safe(l, n, &block->ccw_queue) {
+		cqr = list_entry(l, struct dasd_ccw_req, blocklist);
+		if (cqr->status != DASD_CQR_DONE &&
+		    cqr->status != DASD_CQR_FAILED &&
+		    cqr->status != DASD_CQR_NEED_ERP &&
+		    cqr->status != DASD_CQR_TERMINATED)
+			continue;
+
+		if (cqr->status == DASD_CQR_TERMINATED) {
+			base->discipline->handle_terminated_request(cqr);
+			goto restart;
+		}
+
+		/*  Process requests that may be recovered */
+		if (cqr->status == DASD_CQR_NEED_ERP) {
+			erp_fn = base->discipline->erp_action(cqr);
+			if (IS_ERR(erp_fn(cqr)))
+				continue;
+			goto restart;
+		}
+
+		/* log sense for fatal error */
+		if (cqr->status == DASD_CQR_FAILED) {
+			dasd_log_sense(cqr, &cqr->irb);
+		}
+
+		/* First of all call extended error reporting. */
+		if (dasd_eer_enabled(base) &&
+		    cqr->status == DASD_CQR_FAILED) {
+			dasd_eer_write(base, cqr, DASD_EER_FATALERROR);
+
+			/* restart request  */
+			cqr->status = DASD_CQR_FILLED;
+			cqr->retries = 255;
+			spin_lock_irqsave(get_ccwdev_lock(base->cdev), flags);
+			dasd_device_set_stop_bits(base, DASD_STOPPED_QUIESCE);
+			spin_unlock_irqrestore(get_ccwdev_lock(base->cdev),
+					       flags);
+			goto restart;
+		}
+
+		/* Process finished ERP request. */
+		if (cqr->refers) {
+			__dasd_process_erp(base, cqr);
+			goto restart;
+		}
+
+		/* Rechain finished requests to final queue */
+		cqr->endclk = get_tod_clock();
+		list_move_tail(&cqr->blocklist, final_queue);
+	}
+}
+
+static void dasd_return_cqr_cb(struct dasd_ccw_req *cqr, void *data)
+{
+	dasd_schedule_block_bh(cqr->block);
+}
+
+static void __dasd_block_start_head(struct dasd_block *block)
+{
+	struct dasd_ccw_req *cqr;
+
+	if (list_empty(&block->ccw_queue))
+		return;
+	/* We allways begin with the first requests on the queue, as some
+	 * of previously started requests have to be enqueued on a
+	 * dasd_device again for error recovery.
+	 */
+	list_for_each_entry(cqr, &block->ccw_queue, blocklist) {
+		if (cqr->status != DASD_CQR_FILLED)
+			continue;
+		if (test_bit(DASD_FLAG_LOCK_STOLEN, &block->base->flags) &&
+		    !test_bit(DASD_CQR_ALLOW_SLOCK, &cqr->flags)) {
+			cqr->status = DASD_CQR_FAILED;
+			cqr->intrc = -EPERM;
+			dasd_schedule_block_bh(block);
+			continue;
+		}
+		/* Non-temporary stop condition will trigger fail fast */
+		if (block->base->stopped & ~DASD_STOPPED_PENDING &&
+		    test_bit(DASD_CQR_FLAGS_FAILFAST, &cqr->flags) &&
+		    (!dasd_eer_enabled(block->base))) {
+			cqr->status = DASD_CQR_FAILED;
+			cqr->intrc = -ENOLINK;
+			dasd_schedule_block_bh(block);
+			continue;
+		}
+		/* Don't try to start requests if device is stopped */
+		if (block->base->stopped)
+			return;
+
+		/* just a fail safe check, should not happen */
+		if (!cqr->startdev)
+			cqr->startdev = block->base;
+
+		/* make sure that the requests we submit find their way back */
+		cqr->callback = dasd_return_cqr_cb;
+
+		dasd_add_request_tail(cqr);
+	}
+}
+
+/*
+ * Central dasd_block layer routine. Takes requests from the generic
+ * block layer request queue, creates ccw requests, enqueues them on
+ * a dasd_device and processes ccw requests that have been returned.
+ */
+static void dasd_block_tasklet(struct dasd_block *block)
+{
+	struct list_head final_queue;
+	struct list_head *l, *n;
+	struct dasd_ccw_req *cqr;
+
+	atomic_set(&block->tasklet_scheduled, 0);
+	INIT_LIST_HEAD(&final_queue);
+	spin_lock(&block->queue_lock);
+	/* Finish off requests on ccw queue */
+	__dasd_process_block_ccw_queue(block, &final_queue);
+	spin_unlock(&block->queue_lock);
+	/* Now call the callback function of requests with final status */
+	spin_lock_irq(&block->request_queue_lock);
+	list_for_each_safe(l, n, &final_queue) {
+		cqr = list_entry(l, struct dasd_ccw_req, blocklist);
+		list_del_init(&cqr->blocklist);
+		__dasd_cleanup_cqr(cqr);
+	}
+	spin_lock(&block->queue_lock);
+	/* Get new request from the block device request queue */
+	__dasd_process_request_queue(block);
+	/* Now check if the head of the ccw queue needs to be started. */
+	__dasd_block_start_head(block);
+	spin_unlock(&block->queue_lock);
+	spin_unlock_irq(&block->request_queue_lock);
+	if (waitqueue_active(&shutdown_waitq))
+		wake_up(&shutdown_waitq);
+	dasd_put_device(block->base);
+}
+
+static void _dasd_wake_block_flush_cb(struct dasd_ccw_req *cqr, void *data)
+{
+	wake_up(&dasd_flush_wq);
+}
+
+/*
+ * Requeue a request back to the block request queue
+ * only works for block requests
+ */
+static int _dasd_requeue_request(struct dasd_ccw_req *cqr)
+{
+	struct dasd_block *block = cqr->block;
+	struct request *req;
+	unsigned long flags;
+
+	if (!block)
+		return -EINVAL;
+	spin_lock_irqsave(&block->queue_lock, flags);
+	req = (struct request *) cqr->callback_data;
+	blk_requeue_request(block->request_queue, req);
+	spin_unlock_irqrestore(&block->queue_lock, flags);
+
+	return 0;
+}
+
+/*
+ * Go through all request on the dasd_block request queue, cancel them
+ * on the respective dasd_device, and return them to the generic
+ * block layer.
+ */
+static int dasd_flush_block_queue(struct dasd_block *block)
+{
+	struct dasd_ccw_req *cqr, *n;
+	int rc, i;
+	struct list_head flush_queue;
+
+	INIT_LIST_HEAD(&flush_queue);
+	spin_lock_bh(&block->queue_lock);
+	rc = 0;
+restart:
+	list_for_each_entry_safe(cqr, n, &block->ccw_queue, blocklist) {
+		/* if this request currently owned by a dasd_device cancel it */
+		if (cqr->status >= DASD_CQR_QUEUED)
+			rc = dasd_cancel_req(cqr);
+		if (rc < 0)
+			break;
+		/* Rechain request (including erp chain) so it won't be
+		 * touched by the dasd_block_tasklet anymore.
+		 * Replace the callback so we notice when the request
+		 * is returned from the dasd_device layer.
+		 */
+		cqr->callback = _dasd_wake_block_flush_cb;
+		for (i = 0; cqr != NULL; cqr = cqr->refers, i++)
+			list_move_tail(&cqr->blocklist, &flush_queue);
+		if (i > 1)
+			/* moved more than one request - need to restart */
+			goto restart;
+	}
+	spin_unlock_bh(&block->queue_lock);
+	/* Now call the callback function of flushed requests */
+restart_cb:
+	list_for_each_entry_safe(cqr, n, &flush_queue, blocklist) {
+		wait_event(dasd_flush_wq, (cqr->status < DASD_CQR_QUEUED));
+		/* Process finished ERP request. */
+		if (cqr->refers) {
+			spin_lock_bh(&block->queue_lock);
+			__dasd_process_erp(block->base, cqr);
+			spin_unlock_bh(&block->queue_lock);
+			/* restart list_for_xx loop since dasd_process_erp
+			 * might remove multiple elements */
+			goto restart_cb;
+		}
+		/* call the callback function */
+		spin_lock_irq(&block->request_queue_lock);
+		cqr->endclk = get_tod_clock();
+		list_del_init(&cqr->blocklist);
+		__dasd_cleanup_cqr(cqr);
+		spin_unlock_irq(&block->request_queue_lock);
+	}
+	return rc;
+}
+
+/*
+ * Schedules a call to dasd_tasklet over the device tasklet.
+ */
+void dasd_schedule_block_bh(struct dasd_block *block)
+{
+	/* Protect against rescheduling. */
+	if (atomic_cmpxchg(&block->tasklet_scheduled, 0, 1) != 0)
+		return;
+	/* life cycle of block is bound to it's base device */
+	dasd_get_device(block->base);
+	tasklet_hi_schedule(&block->tasklet);
+}
+EXPORT_SYMBOL(dasd_schedule_block_bh);
+
+
+/*
+ * SECTION: external block device operations
+ * (request queue handling, open, release, etc.)
+ */
+
+/*
+ * Dasd request queue function. Called from ll_rw_blk.c
+ */
+static void do_dasd_request(struct request_queue *queue)
+{
+	struct dasd_block *block;
+
+	block = queue->queuedata;
+	spin_lock(&block->queue_lock);
+	/* Get new request from the block device request queue */
+	__dasd_process_request_queue(block);
+	/* Now check if the head of the ccw queue needs to be started. */
+	__dasd_block_start_head(block);
+	spin_unlock(&block->queue_lock);
+}
+
+/*
+ * Block timeout callback, called from the block layer
+ *
+ * request_queue lock is held on entry.
+ *
+ * Return values:
+ * BLK_EH_RESET_TIMER if the request should be left running
+ * BLK_EH_NOT_HANDLED if the request is handled or terminated
+ *		      by the driver.
+ */
+enum blk_eh_timer_return dasd_times_out(struct request *req)
+{
+	struct dasd_ccw_req *cqr = req->completion_data;
+	struct dasd_block *block = req->q->queuedata;
+	struct dasd_device *device;
+	int rc = 0;
+
+	if (!cqr)
+		return BLK_EH_NOT_HANDLED;
+
+	device = cqr->startdev ? cqr->startdev : block->base;
+	if (!device->blk_timeout)
+		return BLK_EH_RESET_TIMER;
+	DBF_DEV_EVENT(DBF_WARNING, device,
+		      " dasd_times_out cqr %p status %x",
+		      cqr, cqr->status);
+
+	spin_lock(&block->queue_lock);
+	spin_lock(get_ccwdev_lock(device->cdev));
+	cqr->retries = -1;
+	cqr->intrc = -ETIMEDOUT;
+	if (cqr->status >= DASD_CQR_QUEUED) {
+		spin_unlock(get_ccwdev_lock(device->cdev));
+		rc = dasd_cancel_req(cqr);
+	} else if (cqr->status == DASD_CQR_FILLED ||
+		   cqr->status == DASD_CQR_NEED_ERP) {
+		cqr->status = DASD_CQR_TERMINATED;
+		spin_unlock(get_ccwdev_lock(device->cdev));
+	} else if (cqr->status == DASD_CQR_IN_ERP) {
+		struct dasd_ccw_req *searchcqr, *nextcqr, *tmpcqr;
+
+		list_for_each_entry_safe(searchcqr, nextcqr,
+					 &block->ccw_queue, blocklist) {
+			tmpcqr = searchcqr;
+			while (tmpcqr->refers)
+				tmpcqr = tmpcqr->refers;
+			if (tmpcqr != cqr)
+				continue;
+			/* searchcqr is an ERP request for cqr */
+			searchcqr->retries = -1;
+			searchcqr->intrc = -ETIMEDOUT;
+			if (searchcqr->status >= DASD_CQR_QUEUED) {
+				spin_unlock(get_ccwdev_lock(device->cdev));
+				rc = dasd_cancel_req(searchcqr);
+				spin_lock(get_ccwdev_lock(device->cdev));
+			} else if ((searchcqr->status == DASD_CQR_FILLED) ||
+				   (searchcqr->status == DASD_CQR_NEED_ERP)) {
+				searchcqr->status = DASD_CQR_TERMINATED;
+				rc = 0;
+			} else if (searchcqr->status == DASD_CQR_IN_ERP) {
+				/*
+				 * Shouldn't happen; most recent ERP
+				 * request is at the front of queue
+				 */
+				continue;
+			}
+			break;
+		}
+		spin_unlock(get_ccwdev_lock(device->cdev));
+	}
+	dasd_schedule_block_bh(block);
+	spin_unlock(&block->queue_lock);
+
+	return rc ? BLK_EH_RESET_TIMER : BLK_EH_NOT_HANDLED;
+}
+
+/*
+ * Allocate and initialize request queue and default I/O scheduler.
+ */
+static int dasd_alloc_queue(struct dasd_block *block)
+{
+	block->request_queue = blk_init_queue(do_dasd_request,
+					       &block->request_queue_lock);
+	if (block->request_queue == NULL)
+		return -ENOMEM;
+
+	block->request_queue->queuedata = block;
+
+	return 0;
+}
+
+/*
+ * Allocate and initialize request queue.
+ */
+static void dasd_setup_queue(struct dasd_block *block)
+{
+	int max;
+
+	if (block->base->features & DASD_FEATURE_USERAW) {
+		/*
+		 * the max_blocks value for raw_track access is 256
+		 * it is higher than the native ECKD value because we
+		 * only need one ccw per track
+		 * so the max_hw_sectors are
+		 * 2048 x 512B = 1024kB = 16 tracks
+		 */
+		max = 2048;
+	} else {
+		max = block->base->discipline->max_blocks << block->s2b_shift;
+	}
+	blk_queue_logical_block_size(block->request_queue,
+				     block->bp_block);
+	blk_queue_max_hw_sectors(block->request_queue, max);
+	blk_queue_max_segments(block->request_queue, -1L);
+	/* with page sized segments we can translate each segement into
+	 * one idaw/tidaw
+	 */
+	blk_queue_max_segment_size(block->request_queue, PAGE_SIZE);
+	blk_queue_segment_boundary(block->request_queue, PAGE_SIZE - 1);
+}
+
+/*
+ * Deactivate and free request queue.
+ */
+static void dasd_free_queue(struct dasd_block *block)
+{
+	if (block->request_queue) {
+		blk_cleanup_queue(block->request_queue);
+		block->request_queue = NULL;
+	}
+}
+
+/*
+ * Flush request on the request queue.
+ */
+static void dasd_flush_request_queue(struct dasd_block *block)
+{
+	struct request *req;
+
+	if (!block->request_queue)
+		return;
+
+	spin_lock_irq(&block->request_queue_lock);
+	while ((req = blk_fetch_request(block->request_queue)))
+		__blk_end_request_all(req, -EIO);
+	spin_unlock_irq(&block->request_queue_lock);
+}
+
+static int dasd_open(struct block_device *bdev, fmode_t mode)
+{
+	struct dasd_device *base;
+	int rc;
+
+	base = dasd_device_from_gendisk(bdev->bd_disk);
+	if (!base)
+		return -ENODEV;
+
+	atomic_inc(&base->block->open_count);
+	if (test_bit(DASD_FLAG_OFFLINE, &base->flags)) {
+		rc = -ENODEV;
+		goto unlock;
+	}
+
+	if (!try_module_get(base->discipline->owner)) {
+		rc = -EINVAL;
+		goto unlock;
+	}
+
+	if (dasd_probeonly) {
+		dev_info(&base->cdev->dev,
+			 "Accessing the DASD failed because it is in "
+			 "probeonly mode\n");
+		rc = -EPERM;
+		goto out;
+	}
+
+	if (base->state <= DASD_STATE_BASIC) {
+		DBF_DEV_EVENT(DBF_ERR, base, " %s",
+			      " Cannot open unrecognized device");
+		rc = -ENODEV;
+		goto out;
+	}
+
+	if ((mode & FMODE_WRITE) &&
+	    (test_bit(DASD_FLAG_DEVICE_RO, &base->flags) ||
+	     (base->features & DASD_FEATURE_READONLY))) {
+		rc = -EROFS;
+		goto out;
+	}
+
+	dasd_put_device(base);
+	return 0;
+
+out:
+	module_put(base->discipline->owner);
+unlock:
+	atomic_dec(&base->block->open_count);
+	dasd_put_device(base);
+	return rc;
+}
+
+static void dasd_release(struct gendisk *disk, fmode_t mode)
+{
+	struct dasd_device *base = dasd_device_from_gendisk(disk);
+	if (base) {
+		atomic_dec(&base->block->open_count);
+		module_put(base->discipline->owner);
+		dasd_put_device(base);
+	}
+}
+
+/*
+ * Return disk geometry.
+ */
+static int dasd_getgeo(struct block_device *bdev, struct hd_geometry *geo)
+{
+	struct dasd_device *base;
+
+	base = dasd_device_from_gendisk(bdev->bd_disk);
+	if (!base)
+		return -ENODEV;
+
+	if (!base->discipline ||
+	    !base->discipline->fill_geometry) {
+		dasd_put_device(base);
+		return -EINVAL;
+	}
+	base->discipline->fill_geometry(base->block, geo);
+	geo->start = get_start_sect(bdev) >> base->block->s2b_shift;
+	dasd_put_device(base);
+	return 0;
+}
+
+const struct block_device_operations
+dasd_device_operations = {
+	.owner		= THIS_MODULE,
+	.open		= dasd_open,
+	.release	= dasd_release,
+	.ioctl		= dasd_ioctl,
+	.compat_ioctl	= dasd_ioctl,
+	.getgeo		= dasd_getgeo,
+};
+
+/*******************************************************************************
+ * end of block device operations
+ */
+
+static void
+dasd_exit(void)
+{
+#ifdef CONFIG_PROC_FS
+	dasd_proc_exit();
+#endif
+	dasd_eer_exit();
+        if (dasd_page_cache != NULL) {
+		kmem_cache_destroy(dasd_page_cache);
+		dasd_page_cache = NULL;
+	}
+	dasd_gendisk_exit();
+	dasd_devmap_exit();
+	if (dasd_debug_area != NULL) {
+		debug_unregister(dasd_debug_area);
+		dasd_debug_area = NULL;
+	}
+	dasd_statistics_removeroot();
+}
+
+/*
+ * SECTION: common functions for ccw_driver use
+ */
+
+/*
+ * Is the device read-only?
+ * Note that this function does not report the setting of the
+ * readonly device attribute, but how it is configured in z/VM.
+ */
+int dasd_device_is_ro(struct dasd_device *device)
+{
+	struct ccw_dev_id dev_id;
+	struct diag210 diag_data;
+	int rc;
+
+	if (!MACHINE_IS_VM)
+		return 0;
+	ccw_device_get_id(device->cdev, &dev_id);
+	memset(&diag_data, 0, sizeof(diag_data));
+	diag_data.vrdcdvno = dev_id.devno;
+	diag_data.vrdclen = sizeof(diag_data);
+	rc = diag210(&diag_data);
+	if (rc == 0 || rc == 2) {
+		return diag_data.vrdcvfla & 0x80;
+	} else {
+		DBF_EVENT(DBF_WARNING, "diag210 failed for dev=%04x with rc=%d",
+			  dev_id.devno, rc);
+		return 0;
+	}
+}
+EXPORT_SYMBOL_GPL(dasd_device_is_ro);
+
+static void dasd_generic_auto_online(void *data, async_cookie_t cookie)
+{
+	struct ccw_device *cdev = data;
+	int ret;
+
+	ret = ccw_device_set_online(cdev);
+	if (ret)
+		pr_warn("%s: Setting the DASD online failed with rc=%d\n",
+			dev_name(&cdev->dev), ret);
+}
+
+/*
+ * Initial attempt at a probe function. this can be simplified once
+ * the other detection code is gone.
+ */
+int dasd_generic_probe(struct ccw_device *cdev,
+		       struct dasd_discipline *discipline)
+{
+	int ret;
+
+	ret = dasd_add_sysfs_files(cdev);
+	if (ret) {
+		DBF_EVENT_DEVID(DBF_WARNING, cdev, "%s",
+				"dasd_generic_probe: could not add "
+				"sysfs entries");
+		return ret;
+	}
+	cdev->handler = &dasd_int_handler;
+
+	/*
+	 * Automatically online either all dasd devices (dasd_autodetect)
+	 * or all devices specified with dasd= parameters during
+	 * initial probe.
+	 */
+	if ((dasd_get_feature(cdev, DASD_FEATURE_INITIAL_ONLINE) > 0 ) ||
+	    (dasd_autodetect && dasd_busid_known(dev_name(&cdev->dev)) != 0))
+		async_schedule(dasd_generic_auto_online, cdev);
+	return 0;
+}
+EXPORT_SYMBOL_GPL(dasd_generic_probe);
+
+/*
+ * This will one day be called from a global not_oper handler.
+ * It is also used by driver_unregister during module unload.
+ */
+void dasd_generic_remove(struct ccw_device *cdev)
+{
+	struct dasd_device *device;
+	struct dasd_block *block;
+
+	cdev->handler = NULL;
+
+	device = dasd_device_from_cdev(cdev);
+	if (IS_ERR(device)) {
+		dasd_remove_sysfs_files(cdev);
+		return;
+	}
+	if (test_and_set_bit(DASD_FLAG_OFFLINE, &device->flags) &&
+	    !test_bit(DASD_FLAG_SAFE_OFFLINE_RUNNING, &device->flags)) {
+		/* Already doing offline processing */
+		dasd_put_device(device);
+		dasd_remove_sysfs_files(cdev);
+		return;
+	}
+	/*
+	 * This device is removed unconditionally. Set offline
+	 * flag to prevent dasd_open from opening it while it is
+	 * no quite down yet.
+	 */
+	dasd_set_target_state(device, DASD_STATE_NEW);
+	/* dasd_delete_device destroys the device reference. */
+	block = device->block;
+	dasd_delete_device(device);
+	/*
+	 * life cycle of block is bound to device, so delete it after
+	 * device was safely removed
+	 */
+	if (block)
+		dasd_free_block(block);
+
+	dasd_remove_sysfs_files(cdev);
+}
+EXPORT_SYMBOL_GPL(dasd_generic_remove);
+
+/*
+ * Activate a device. This is called from dasd_{eckd,fba}_probe() when either
+ * the device is detected for the first time and is supposed to be used
+ * or the user has started activation through sysfs.
+ */
+int dasd_generic_set_online(struct ccw_device *cdev,
+			    struct dasd_discipline *base_discipline)
+{
+	struct dasd_discipline *discipline;
+	struct dasd_device *device;
+	int rc;
+
+	/* first online clears initial online feature flag */
+	dasd_set_feature(cdev, DASD_FEATURE_INITIAL_ONLINE, 0);
+	device = dasd_create_device(cdev);
+	if (IS_ERR(device))
+		return PTR_ERR(device);
+
+	discipline = base_discipline;
+	if (device->features & DASD_FEATURE_USEDIAG) {
+	  	if (!dasd_diag_discipline_pointer) {
+			pr_warn("%s Setting the DASD online failed because of missing DIAG discipline\n",
+				dev_name(&cdev->dev));
+			dasd_delete_device(device);
+			return -ENODEV;
+		}
+		discipline = dasd_diag_discipline_pointer;
+	}
+	if (!try_module_get(base_discipline->owner)) {
+		dasd_delete_device(device);
+		return -EINVAL;
+	}
+	if (!try_module_get(discipline->owner)) {
+		module_put(base_discipline->owner);
+		dasd_delete_device(device);
+		return -EINVAL;
+	}
+	device->base_discipline = base_discipline;
+	device->discipline = discipline;
+
+	/* check_device will allocate block device if necessary */
+	rc = discipline->check_device(device);
+	if (rc) {
+		pr_warn("%s Setting the DASD online with discipline %s failed with rc=%i\n",
+			dev_name(&cdev->dev), discipline->name, rc);
+		module_put(discipline->owner);
+		module_put(base_discipline->owner);
+		dasd_delete_device(device);
+		return rc;
+	}
+
+	dasd_set_target_state(device, DASD_STATE_ONLINE);
+	if (device->state <= DASD_STATE_KNOWN) {
+		pr_warn("%s Setting the DASD online failed because of a missing discipline\n",
+			dev_name(&cdev->dev));
+		rc = -ENODEV;
+		dasd_set_target_state(device, DASD_STATE_NEW);
+		if (device->block)
+			dasd_free_block(device->block);
+		dasd_delete_device(device);
+	} else
+		pr_debug("dasd_generic device %s found\n",
+				dev_name(&cdev->dev));
+
+	wait_event(dasd_init_waitq, _wait_for_device(device));
+
+	dasd_put_device(device);
+	return rc;
+}
+EXPORT_SYMBOL_GPL(dasd_generic_set_online);
+
+int dasd_generic_set_offline(struct ccw_device *cdev)
+{
+	struct dasd_device *device;
+	struct dasd_block *block;
+	int max_count, open_count, rc;
+
+	rc = 0;
+	device = dasd_device_from_cdev(cdev);
+	if (IS_ERR(device))
+		return PTR_ERR(device);
+
+	/*
+	 * We must make sure that this device is currently not in use.
+	 * The open_count is increased for every opener, that includes
+	 * the blkdev_get in dasd_scan_partitions. We are only interested
+	 * in the other openers.
+	 */
+	if (device->block) {
+		max_count = device->block->bdev ? 0 : -1;
+		open_count = atomic_read(&device->block->open_count);
+		if (open_count > max_count) {
+			if (open_count > 0)
+				pr_warn("%s: The DASD cannot be set offline with open count %i\n",
+					dev_name(&cdev->dev), open_count);
+			else
+				pr_warn("%s: The DASD cannot be set offline while it is in use\n",
+					dev_name(&cdev->dev));
+			clear_bit(DASD_FLAG_OFFLINE, &device->flags);
+			dasd_put_device(device);
+			return -EBUSY;
+		}
+	}
+
+	if (test_bit(DASD_FLAG_SAFE_OFFLINE_RUNNING, &device->flags)) {
+		/*
+		 * safe offline already running
+		 * could only be called by normal offline so safe_offline flag
+		 * needs to be removed to run normal offline and kill all I/O
+		 */
+		if (test_and_set_bit(DASD_FLAG_OFFLINE, &device->flags)) {
+			/* Already doing normal offline processing */
+			dasd_put_device(device);
+			return -EBUSY;
+		} else
+			clear_bit(DASD_FLAG_SAFE_OFFLINE, &device->flags);
+
+	} else
+		if (test_bit(DASD_FLAG_OFFLINE, &device->flags)) {
+			/* Already doing offline processing */
+			dasd_put_device(device);
+			return -EBUSY;
+		}
+
+	/*
+	 * if safe_offline called set safe_offline_running flag and
+	 * clear safe_offline so that a call to normal offline
+	 * can overrun safe_offline processing
+	 */
+	if (test_and_clear_bit(DASD_FLAG_SAFE_OFFLINE, &device->flags) &&
+	    !test_and_set_bit(DASD_FLAG_SAFE_OFFLINE_RUNNING, &device->flags)) {
+		/*
+		 * If we want to set the device safe offline all IO operations
+		 * should be finished before continuing the offline process
+		 * so sync bdev first and then wait for our queues to become
+		 * empty
+		 */
+		/* sync blockdev and partitions */
+		rc = fsync_bdev(device->block->bdev);
+		if (rc != 0)
+			goto interrupted;
+
+		/* schedule device tasklet and wait for completion */
+		dasd_schedule_device_bh(device);
+		rc = wait_event_interruptible(shutdown_waitq,
+					      _wait_for_empty_queues(device));
+		if (rc != 0)
+			goto interrupted;
+	}
+
+	set_bit(DASD_FLAG_OFFLINE, &device->flags);
+	dasd_set_target_state(device, DASD_STATE_NEW);
+	/* dasd_delete_device destroys the device reference. */
+	block = device->block;
+	dasd_delete_device(device);
+	/*
+	 * life cycle of block is bound to device, so delete it after
+	 * device was safely removed
+	 */
+	if (block)
+		dasd_free_block(block);
+	return 0;
+
+interrupted:
+	/* interrupted by signal */
+	clear_bit(DASD_FLAG_SAFE_OFFLINE, &device->flags);
+	clear_bit(DASD_FLAG_SAFE_OFFLINE_RUNNING, &device->flags);
+	clear_bit(DASD_FLAG_OFFLINE, &device->flags);
+	dasd_put_device(device);
+	return rc;
+}
+EXPORT_SYMBOL_GPL(dasd_generic_set_offline);
+
+int dasd_generic_last_path_gone(struct dasd_device *device)
+{
+	struct dasd_ccw_req *cqr;
+
+	dev_warn(&device->cdev->dev, "No operational channel path is left "
+		 "for the device\n");
+	DBF_DEV_EVENT(DBF_WARNING, device, "%s", "last path gone");
+	/* First of all call extended error reporting. */
+	dasd_eer_write(device, NULL, DASD_EER_NOPATH);
+
+	if (device->state < DASD_STATE_BASIC)
+		return 0;
+	/* Device is active. We want to keep it. */
+	list_for_each_entry(cqr, &device->ccw_queue, devlist)
+		if ((cqr->status == DASD_CQR_IN_IO) ||
+		    (cqr->status == DASD_CQR_CLEAR_PENDING)) {
+			cqr->status = DASD_CQR_QUEUED;
+			cqr->retries++;
+		}
+	dasd_device_set_stop_bits(device, DASD_STOPPED_DC_WAIT);
+	dasd_device_clear_timer(device);
+	dasd_schedule_device_bh(device);
+	return 1;
+}
+EXPORT_SYMBOL_GPL(dasd_generic_last_path_gone);
+
+int dasd_generic_path_operational(struct dasd_device *device)
+{
+	dev_info(&device->cdev->dev, "A channel path to the device has become "
+		 "operational\n");
+	DBF_DEV_EVENT(DBF_WARNING, device, "%s", "path operational");
+	dasd_device_remove_stop_bits(device, DASD_STOPPED_DC_WAIT);
+	if (device->stopped & DASD_UNRESUMED_PM) {
+		dasd_device_remove_stop_bits(device, DASD_UNRESUMED_PM);
+		dasd_restore_device(device);
+		return 1;
+	}
+	dasd_schedule_device_bh(device);
+	if (device->block)
+		dasd_schedule_block_bh(device->block);
+
+	if (!device->stopped)
+		wake_up(&generic_waitq);
+
+	return 1;
+}
+EXPORT_SYMBOL_GPL(dasd_generic_path_operational);
+
+int dasd_generic_notify(struct ccw_device *cdev, int event)
+{
+	struct dasd_device *device;
+	int ret;
+
+	device = dasd_device_from_cdev_locked(cdev);
+	if (IS_ERR(device))
+		return 0;
+	ret = 0;
+	switch (event) {
+	case CIO_GONE:
+	case CIO_BOXED:
+	case CIO_NO_PATH:
+		device->path_data.opm = 0;
+		device->path_data.ppm = 0;
+		device->path_data.npm = 0;
+		ret = dasd_generic_last_path_gone(device);
+		break;
+	case CIO_OPER:
+		ret = 1;
+		if (device->path_data.opm)
+			ret = dasd_generic_path_operational(device);
+		break;
+	}
+	dasd_put_device(device);
+	return ret;
+}
+EXPORT_SYMBOL_GPL(dasd_generic_notify);
+
+void dasd_generic_path_event(struct ccw_device *cdev, int *path_event)
+{
+	int chp;
+	__u8 oldopm, eventlpm;
+	struct dasd_device *device;
+
+	device = dasd_device_from_cdev_locked(cdev);
+	if (IS_ERR(device))
+		return;
+	for (chp = 0; chp < 8; chp++) {
+		eventlpm = 0x80 >> chp;
+		if (path_event[chp] & PE_PATH_GONE) {
+			oldopm = device->path_data.opm;
+			device->path_data.opm &= ~eventlpm;
+			device->path_data.ppm &= ~eventlpm;
+			device->path_data.npm &= ~eventlpm;
+			if (oldopm && !device->path_data.opm) {
+				dev_warn(&device->cdev->dev,
+					 "No verified channel paths remain "
+					 "for the device\n");
+				DBF_DEV_EVENT(DBF_WARNING, device,
+					      "%s", "last verified path gone");
+				dasd_eer_write(device, NULL, DASD_EER_NOPATH);
+				dasd_device_set_stop_bits(device,
+							  DASD_STOPPED_DC_WAIT);
+			}
+		}
+		if (path_event[chp] & PE_PATH_AVAILABLE) {
+			device->path_data.opm &= ~eventlpm;
+			device->path_data.ppm &= ~eventlpm;
+			device->path_data.npm &= ~eventlpm;
+			device->path_data.tbvpm |= eventlpm;
+			dasd_schedule_device_bh(device);
+		}
+		if (path_event[chp] & PE_PATHGROUP_ESTABLISHED) {
+			if (!(device->path_data.opm & eventlpm) &&
+			    !(device->path_data.tbvpm & eventlpm)) {
+				/*
+				 * we can not establish a pathgroup on an
+				 * unavailable path, so trigger a path
+				 * verification first
+				 */
+				device->path_data.tbvpm |= eventlpm;
+				dasd_schedule_device_bh(device);
+			}
+			DBF_DEV_EVENT(DBF_WARNING, device, "%s",
+				      "Pathgroup re-established\n");
+			if (device->discipline->kick_validate)
+				device->discipline->kick_validate(device);
+		}
+	}
+	dasd_put_device(device);
+}
+EXPORT_SYMBOL_GPL(dasd_generic_path_event);
+
+int dasd_generic_verify_path(struct dasd_device *device, __u8 lpm)
+{
+	if (!device->path_data.opm && lpm) {
+		device->path_data.opm = lpm;
+		dasd_generic_path_operational(device);
+	} else
+		device->path_data.opm |= lpm;
+	return 0;
+}
+EXPORT_SYMBOL_GPL(dasd_generic_verify_path);
+
+
+int dasd_generic_pm_freeze(struct ccw_device *cdev)
+{
+	struct dasd_device *device = dasd_device_from_cdev(cdev);
+	struct list_head freeze_queue;
+	struct dasd_ccw_req *cqr, *n;
+	struct dasd_ccw_req *refers;
+	int rc;
+
+	if (IS_ERR(device))
+		return PTR_ERR(device);
+
+	/* mark device as suspended */
+	set_bit(DASD_FLAG_SUSPENDED, &device->flags);
+
+	if (device->discipline->freeze)
+		rc = device->discipline->freeze(device);
+
+	/* disallow new I/O  */
+	dasd_device_set_stop_bits(device, DASD_STOPPED_PM);
+
+	/* clear active requests and requeue them to block layer if possible */
+	INIT_LIST_HEAD(&freeze_queue);
+	spin_lock_irq(get_ccwdev_lock(cdev));
+	rc = 0;
+	list_for_each_entry_safe(cqr, n, &device->ccw_queue, devlist) {
+		/* Check status and move request to flush_queue */
+		if (cqr->status == DASD_CQR_IN_IO) {
+			rc = device->discipline->term_IO(cqr);
+			if (rc) {
+				/* unable to terminate requeust */
+				dev_err(&device->cdev->dev,
+					"Unable to terminate request %p "
+					"on suspend\n", cqr);
+				spin_unlock_irq(get_ccwdev_lock(cdev));
+				dasd_put_device(device);
+				return rc;
+			}
+		}
+		list_move_tail(&cqr->devlist, &freeze_queue);
+	}
+	spin_unlock_irq(get_ccwdev_lock(cdev));
+
+	list_for_each_entry_safe(cqr, n, &freeze_queue, devlist) {
+		wait_event(dasd_flush_wq,
+			   (cqr->status != DASD_CQR_CLEAR_PENDING));
+		if (cqr->status == DASD_CQR_CLEARED)
+			cqr->status = DASD_CQR_QUEUED;
+
+		/* requeue requests to blocklayer will only work for
+		   block device requests */
+		if (_dasd_requeue_request(cqr))
+			continue;
+
+		/* remove requests from device and block queue */
+		list_del_init(&cqr->devlist);
+		while (cqr->refers != NULL) {
+			refers = cqr->refers;
+			/* remove the request from the block queue */
+			list_del(&cqr->blocklist);
+			/* free the finished erp request */
+			dasd_free_erp_request(cqr, cqr->memdev);
+			cqr = refers;
+		}
+		if (cqr->block)
+			list_del_init(&cqr->blocklist);
+		cqr->block->base->discipline->free_cp(
+			cqr, (struct request *) cqr->callback_data);
+	}
+
+	/*
+	 * if requests remain then they are internal request
+	 * and go back to the device queue
+	 */
+	if (!list_empty(&freeze_queue)) {
+		/* move freeze_queue to start of the ccw_queue */
+		spin_lock_irq(get_ccwdev_lock(cdev));
+		list_splice_tail(&freeze_queue, &device->ccw_queue);
+		spin_unlock_irq(get_ccwdev_lock(cdev));
+	}
+	dasd_put_device(device);
+	return rc;
+}
+EXPORT_SYMBOL_GPL(dasd_generic_pm_freeze);
+
+int dasd_generic_restore_device(struct ccw_device *cdev)
+{
+	struct dasd_device *device = dasd_device_from_cdev(cdev);
+	int rc = 0;
+
+	if (IS_ERR(device))
+		return PTR_ERR(device);
+
+	/* allow new IO again */
+	dasd_device_remove_stop_bits(device,
+				     (DASD_STOPPED_PM | DASD_UNRESUMED_PM));
+
+	dasd_schedule_device_bh(device);
+
+	/*
+	 * call discipline restore function
+	 * if device is stopped do nothing e.g. for disconnected devices
+	 */
+	if (device->discipline->restore && !(device->stopped))
+		rc = device->discipline->restore(device);
+	if (rc || device->stopped)
+		/*
+		 * if the resume failed for the DASD we put it in
+		 * an UNRESUMED stop state
+		 */
+		device->stopped |= DASD_UNRESUMED_PM;
+
+	if (device->block)
+		dasd_schedule_block_bh(device->block);
+
+	clear_bit(DASD_FLAG_SUSPENDED, &device->flags);
+	dasd_put_device(device);
+	return 0;
+}
+EXPORT_SYMBOL_GPL(dasd_generic_restore_device);
+
+static struct dasd_ccw_req *dasd_generic_build_rdc(struct dasd_device *device,
+						   void *rdc_buffer,
+						   int rdc_buffer_size,
+						   int magic)
+{
+	struct dasd_ccw_req *cqr;
+	struct ccw1 *ccw;
+	unsigned long *idaw;
+
+	cqr = dasd_smalloc_request(magic, 1 /* RDC */, rdc_buffer_size, device);
+
+	if (IS_ERR(cqr)) {
+		/* internal error 13 - Allocating the RDC request failed*/
+		dev_err(&device->cdev->dev,
+			 "An error occurred in the DASD device driver, "
+			 "reason=%s\n", "13");
+		return cqr;
+	}
+
+	ccw = cqr->cpaddr;
+	ccw->cmd_code = CCW_CMD_RDC;
+	if (idal_is_needed(rdc_buffer, rdc_buffer_size)) {
+		idaw = (unsigned long *) (cqr->data);
+		ccw->cda = (__u32)(addr_t) idaw;
+		ccw->flags = CCW_FLAG_IDA;
+		idaw = idal_create_words(idaw, rdc_buffer, rdc_buffer_size);
+	} else {
+		ccw->cda = (__u32)(addr_t) rdc_buffer;
+		ccw->flags = 0;
+	}
+
+	ccw->count = rdc_buffer_size;
+	cqr->startdev = device;
+	cqr->memdev = device;
+	cqr->expires = 10*HZ;
+	cqr->retries = 256;
+	cqr->buildclk = get_tod_clock();
+	cqr->status = DASD_CQR_FILLED;
+	return cqr;
+}
+
+
+int dasd_generic_read_dev_chars(struct dasd_device *device, int magic,
+				void *rdc_buffer, int rdc_buffer_size)
+{
+	int ret;
+	struct dasd_ccw_req *cqr;
+
+	cqr = dasd_generic_build_rdc(device, rdc_buffer, rdc_buffer_size,
+				     magic);
+	if (IS_ERR(cqr))
+		return PTR_ERR(cqr);
+
+	ret = dasd_sleep_on(cqr);
+	dasd_sfree_request(cqr, cqr->memdev);
+	return ret;
+}
+EXPORT_SYMBOL_GPL(dasd_generic_read_dev_chars);
+
+/*
+ *   In command mode and transport mode we need to look for sense
+ *   data in different places. The sense data itself is allways
+ *   an array of 32 bytes, so we can unify the sense data access
+ *   for both modes.
+ */
+char *dasd_get_sense(struct irb *irb)
+{
+	struct tsb *tsb = NULL;
+	char *sense = NULL;
+
+	if (scsw_is_tm(&irb->scsw) && (irb->scsw.tm.fcxs == 0x01)) {
+		if (irb->scsw.tm.tcw)
+			tsb = tcw_get_tsb((struct tcw *)(unsigned long)
+					  irb->scsw.tm.tcw);
+		if (tsb && tsb->length == 64 && tsb->flags)
+			switch (tsb->flags & 0x07) {
+			case 1:	/* tsa_iostat */
+				sense = tsb->tsa.iostat.sense;
+				break;
+			case 2: /* tsa_ddpc */
+				sense = tsb->tsa.ddpc.sense;
+				break;
+			default:
+				/* currently we don't use interrogate data */
+				break;
+			}
+	} else if (irb->esw.esw0.erw.cons) {
+		sense = irb->ecw;
+	}
+	return sense;
+}
+EXPORT_SYMBOL_GPL(dasd_get_sense);
+
+void dasd_generic_shutdown(struct ccw_device *cdev)
+{
+	struct dasd_device *device;
+
+	device = dasd_device_from_cdev(cdev);
+	if (IS_ERR(device))
+		return;
+
+	if (device->block)
+		dasd_schedule_block_bh(device->block);
+
+	dasd_schedule_device_bh(device);
+
+	wait_event(shutdown_waitq, _wait_for_empty_queues(device));
+}
+EXPORT_SYMBOL_GPL(dasd_generic_shutdown);
+
+static int __init dasd_init(void)
+{
+	int rc;
+
+	init_waitqueue_head(&dasd_init_waitq);
+	init_waitqueue_head(&dasd_flush_wq);
+	init_waitqueue_head(&generic_waitq);
+	init_waitqueue_head(&shutdown_waitq);
+
+	/* register 'common' DASD debug area, used for all DBF_XXX calls */
+	dasd_debug_area = debug_register("dasd", 1, 1, 8 * sizeof(long));
+	if (dasd_debug_area == NULL) {
+		rc = -ENOMEM;
+		goto failed;
+	}
+	debug_register_view(dasd_debug_area, &debug_sprintf_view);
+	debug_set_level(dasd_debug_area, DBF_WARNING);
+
+	DBF_EVENT(DBF_EMERG, "%s", "debug area created");
+
+	dasd_diag_discipline_pointer = NULL;
+
+	dasd_statistics_createroot();
+
+	rc = dasd_devmap_init();
+	if (rc)
+		goto failed;
+	rc = dasd_gendisk_init();
+	if (rc)
+		goto failed;
+	rc = dasd_parse();
+	if (rc)
+		goto failed;
+	rc = dasd_eer_init();
+	if (rc)
+		goto failed;
+#ifdef CONFIG_PROC_FS
+	rc = dasd_proc_init();
+	if (rc)
+		goto failed;
+#endif
+
+	return 0;
+failed:
+	pr_info("The DASD device driver could not be initialized\n");
+	dasd_exit();
+	return rc;
+}
+
+module_init(dasd_init);
+module_exit(dasd_exit);