Initial import

1 files changed, 1379 insertions, 0 deletions

diff --git a/drivers/s390/char/tape_core.c b/drivers/s390/char/tape_core.c
new file mode 100644
index 000000000..f3b5123fa
--- /dev/null
+++ b/drivers/s390/char/tape_core.c
@@ -0,0 +1,1379 @@
+/*
+ *    basic function of the tape device driver
+ *
+ *  S390 and zSeries version
+ *    Copyright IBM Corp. 2001, 2009
+ *    Author(s): Carsten Otte <cotte@de.ibm.com>
+ *		 Michael Holzheu <holzheu@de.ibm.com>
+ *		 Tuan Ngo-Anh <ngoanh@de.ibm.com>
+ *		 Martin Schwidefsky <schwidefsky@de.ibm.com>
+ *		 Stefan Bader <shbader@de.ibm.com>
+ */
+
+#define KMSG_COMPONENT "tape"
+#define pr_fmt(fmt) KMSG_COMPONENT ": " fmt
+
+#include <linux/module.h>
+#include <linux/init.h>	     // for kernel parameters
+#include <linux/kmod.h>	     // for requesting modules
+#include <linux/spinlock.h>  // for locks
+#include <linux/vmalloc.h>
+#include <linux/list.h>
+#include <linux/slab.h>
+
+#include <asm/types.h>	     // for variable types
+
+#define TAPE_DBF_AREA	tape_core_dbf
+
+#include "tape.h"
+#include "tape_std.h"
+
+#define LONG_BUSY_TIMEOUT 180 /* seconds */
+
+static void __tape_do_irq (struct ccw_device *, unsigned long, struct irb *);
+static void tape_delayed_next_request(struct work_struct *);
+static void tape_long_busy_timeout(unsigned long data);
+
+/*
+ * One list to contain all tape devices of all disciplines, so
+ * we can assign the devices to minor numbers of the same major
+ * The list is protected by the rwlock
+ */
+static LIST_HEAD(tape_device_list);
+static DEFINE_RWLOCK(tape_device_lock);
+
+/*
+ * Pointer to debug area.
+ */
+debug_info_t *TAPE_DBF_AREA = NULL;
+EXPORT_SYMBOL(TAPE_DBF_AREA);
+
+/*
+ * Printable strings for tape enumerations.
+ */
+const char *tape_state_verbose[TS_SIZE] =
+{
+	[TS_UNUSED]   = "UNUSED",
+	[TS_IN_USE]   = "IN_USE",
+	[TS_BLKUSE]   = "BLKUSE",
+	[TS_INIT]     = "INIT  ",
+	[TS_NOT_OPER] = "NOT_OP"
+};
+
+const char *tape_op_verbose[TO_SIZE] =
+{
+	[TO_BLOCK] = "BLK",	[TO_BSB] = "BSB",
+	[TO_BSF] = "BSF",	[TO_DSE] = "DSE",
+	[TO_FSB] = "FSB",	[TO_FSF] = "FSF",
+	[TO_LBL] = "LBL",	[TO_NOP] = "NOP",
+	[TO_RBA] = "RBA",	[TO_RBI] = "RBI",
+	[TO_RFO] = "RFO",	[TO_REW] = "REW",
+	[TO_RUN] = "RUN",	[TO_WRI] = "WRI",
+	[TO_WTM] = "WTM",	[TO_MSEN] = "MSN",
+	[TO_LOAD] = "LOA",	[TO_READ_CONFIG] = "RCF",
+	[TO_READ_ATTMSG] = "RAT",
+	[TO_DIS] = "DIS",	[TO_ASSIGN] = "ASS",
+	[TO_UNASSIGN] = "UAS",  [TO_CRYPT_ON] = "CON",
+	[TO_CRYPT_OFF] = "COF",	[TO_KEKL_SET] = "KLS",
+	[TO_KEKL_QUERY] = "KLQ",[TO_RDC] = "RDC",
+};
+
+static int devid_to_int(struct ccw_dev_id *dev_id)
+{
+	return dev_id->devno + (dev_id->ssid << 16);
+}
+
+/*
+ * Some channel attached tape specific attributes.
+ *
+ * FIXME: In the future the first_minor and blocksize attribute should be
+ *        replaced by a link to the cdev tree.
+ */
+static ssize_t
+tape_medium_state_show(struct device *dev, struct device_attribute *attr, char *buf)
+{
+	struct tape_device *tdev;
+
+	tdev = dev_get_drvdata(dev);
+	return scnprintf(buf, PAGE_SIZE, "%i\n", tdev->medium_state);
+}
+
+static
+DEVICE_ATTR(medium_state, 0444, tape_medium_state_show, NULL);
+
+static ssize_t
+tape_first_minor_show(struct device *dev, struct device_attribute *attr, char *buf)
+{
+	struct tape_device *tdev;
+
+	tdev = dev_get_drvdata(dev);
+	return scnprintf(buf, PAGE_SIZE, "%i\n", tdev->first_minor);
+}
+
+static
+DEVICE_ATTR(first_minor, 0444, tape_first_minor_show, NULL);
+
+static ssize_t
+tape_state_show(struct device *dev, struct device_attribute *attr, char *buf)
+{
+	struct tape_device *tdev;
+
+	tdev = dev_get_drvdata(dev);
+	return scnprintf(buf, PAGE_SIZE, "%s\n", (tdev->first_minor < 0) ?
+		"OFFLINE" : tape_state_verbose[tdev->tape_state]);
+}
+
+static
+DEVICE_ATTR(state, 0444, tape_state_show, NULL);
+
+static ssize_t
+tape_operation_show(struct device *dev, struct device_attribute *attr, char *buf)
+{
+	struct tape_device *tdev;
+	ssize_t rc;
+
+	tdev = dev_get_drvdata(dev);
+	if (tdev->first_minor < 0)
+		return scnprintf(buf, PAGE_SIZE, "N/A\n");
+
+	spin_lock_irq(get_ccwdev_lock(tdev->cdev));
+	if (list_empty(&tdev->req_queue))
+		rc = scnprintf(buf, PAGE_SIZE, "---\n");
+	else {
+		struct tape_request *req;
+
+		req = list_entry(tdev->req_queue.next, struct tape_request,
+			list);
+		rc = scnprintf(buf,PAGE_SIZE, "%s\n", tape_op_verbose[req->op]);
+	}
+	spin_unlock_irq(get_ccwdev_lock(tdev->cdev));
+	return rc;
+}
+
+static
+DEVICE_ATTR(operation, 0444, tape_operation_show, NULL);
+
+static ssize_t
+tape_blocksize_show(struct device *dev, struct device_attribute *attr, char *buf)
+{
+	struct tape_device *tdev;
+
+	tdev = dev_get_drvdata(dev);
+
+	return scnprintf(buf, PAGE_SIZE, "%i\n", tdev->char_data.block_size);
+}
+
+static
+DEVICE_ATTR(blocksize, 0444, tape_blocksize_show, NULL);
+
+static struct attribute *tape_attrs[] = {
+	&dev_attr_medium_state.attr,
+	&dev_attr_first_minor.attr,
+	&dev_attr_state.attr,
+	&dev_attr_operation.attr,
+	&dev_attr_blocksize.attr,
+	NULL
+};
+
+static struct attribute_group tape_attr_group = {
+	.attrs = tape_attrs,
+};
+
+/*
+ * Tape state functions
+ */
+void
+tape_state_set(struct tape_device *device, enum tape_state newstate)
+{
+	const char *str;
+
+	if (device->tape_state == TS_NOT_OPER) {
+		DBF_EVENT(3, "ts_set err: not oper\n");
+		return;
+	}
+	DBF_EVENT(4, "ts. dev:	%x\n", device->first_minor);
+	DBF_EVENT(4, "old ts:\t\n");
+	if (device->tape_state < TS_SIZE && device->tape_state >=0 )
+		str = tape_state_verbose[device->tape_state];
+	else
+		str = "UNKNOWN TS";
+	DBF_EVENT(4, "%s\n", str);
+	DBF_EVENT(4, "new ts:\t\n");
+	if (newstate < TS_SIZE && newstate >= 0)
+		str = tape_state_verbose[newstate];
+	else
+		str = "UNKNOWN TS";
+	DBF_EVENT(4, "%s\n", str);
+	device->tape_state = newstate;
+	wake_up(&device->state_change_wq);
+}
+
+struct tape_med_state_work_data {
+	struct tape_device *device;
+	enum tape_medium_state state;
+	struct work_struct  work;
+};
+
+static void
+tape_med_state_work_handler(struct work_struct *work)
+{
+	static char env_state_loaded[] = "MEDIUM_STATE=LOADED";
+	static char env_state_unloaded[] = "MEDIUM_STATE=UNLOADED";
+	struct tape_med_state_work_data *p =
+		container_of(work, struct tape_med_state_work_data, work);
+	struct tape_device *device = p->device;
+	char *envp[] = { NULL, NULL };
+
+	switch (p->state) {
+	case MS_UNLOADED:
+		pr_info("%s: The tape cartridge has been successfully "
+			"unloaded\n", dev_name(&device->cdev->dev));
+		envp[0] = env_state_unloaded;
+		kobject_uevent_env(&device->cdev->dev.kobj, KOBJ_CHANGE, envp);
+		break;
+	case MS_LOADED:
+		pr_info("%s: A tape cartridge has been mounted\n",
+			dev_name(&device->cdev->dev));
+		envp[0] = env_state_loaded;
+		kobject_uevent_env(&device->cdev->dev.kobj, KOBJ_CHANGE, envp);
+		break;
+	default:
+		break;
+	}
+	tape_put_device(device);
+	kfree(p);
+}
+
+static void
+tape_med_state_work(struct tape_device *device, enum tape_medium_state state)
+{
+	struct tape_med_state_work_data *p;
+
+	p = kzalloc(sizeof(*p), GFP_ATOMIC);
+	if (p) {
+		INIT_WORK(&p->work, tape_med_state_work_handler);
+		p->device = tape_get_device(device);
+		p->state = state;
+		schedule_work(&p->work);
+	}
+}
+
+void
+tape_med_state_set(struct tape_device *device, enum tape_medium_state newstate)
+{
+	enum tape_medium_state oldstate;
+
+	oldstate = device->medium_state;
+	if (oldstate == newstate)
+		return;
+	device->medium_state = newstate;
+	switch(newstate){
+	case MS_UNLOADED:
+		device->tape_generic_status |= GMT_DR_OPEN(~0);
+		if (oldstate == MS_LOADED)
+			tape_med_state_work(device, MS_UNLOADED);
+		break;
+	case MS_LOADED:
+		device->tape_generic_status &= ~GMT_DR_OPEN(~0);
+		if (oldstate == MS_UNLOADED)
+			tape_med_state_work(device, MS_LOADED);
+		break;
+	default:
+		break;
+	}
+	wake_up(&device->state_change_wq);
+}
+
+/*
+ * Stop running ccw. Has to be called with the device lock held.
+ */
+static int
+__tape_cancel_io(struct tape_device *device, struct tape_request *request)
+{
+	int retries;
+	int rc;
+
+	/* Check if interrupt has already been processed */
+	if (request->callback == NULL)
+		return 0;
+
+	rc = 0;
+	for (retries = 0; retries < 5; retries++) {
+		rc = ccw_device_clear(device->cdev, (long) request);
+
+		switch (rc) {
+			case 0:
+				request->status	= TAPE_REQUEST_DONE;
+				return 0;
+			case -EBUSY:
+				request->status	= TAPE_REQUEST_CANCEL;
+				schedule_delayed_work(&device->tape_dnr, 0);
+				return 0;
+			case -ENODEV:
+				DBF_EXCEPTION(2, "device gone, retry\n");
+				break;
+			case -EIO:
+				DBF_EXCEPTION(2, "I/O error, retry\n");
+				break;
+			default:
+				BUG();
+		}
+	}
+
+	return rc;
+}
+
+/*
+ * Add device into the sorted list, giving it the first
+ * available minor number.
+ */
+static int
+tape_assign_minor(struct tape_device *device)
+{
+	struct tape_device *tmp;
+	int minor;
+
+	minor = 0;
+	write_lock(&tape_device_lock);
+	list_for_each_entry(tmp, &tape_device_list, node) {
+		if (minor < tmp->first_minor)
+			break;
+		minor += TAPE_MINORS_PER_DEV;
+	}
+	if (minor >= 256) {
+		write_unlock(&tape_device_lock);
+		return -ENODEV;
+	}
+	device->first_minor = minor;
+	list_add_tail(&device->node, &tmp->node);
+	write_unlock(&tape_device_lock);
+	return 0;
+}
+
+/* remove device from the list */
+static void
+tape_remove_minor(struct tape_device *device)
+{
+	write_lock(&tape_device_lock);
+	list_del_init(&device->node);
+	device->first_minor = -1;
+	write_unlock(&tape_device_lock);
+}
+
+/*
+ * Set a device online.
+ *
+ * This function is called by the common I/O layer to move a device from the
+ * detected but offline into the online state.
+ * If we return an error (RC < 0) the device remains in the offline state. This
+ * can happen if the device is assigned somewhere else, for example.
+ */
+int
+tape_generic_online(struct tape_device *device,
+		   struct tape_discipline *discipline)
+{
+	int rc;
+
+	DBF_LH(6, "tape_enable_device(%p, %p)\n", device, discipline);
+
+	if (device->tape_state != TS_INIT) {
+		DBF_LH(3, "Tapestate not INIT (%d)\n", device->tape_state);
+		return -EINVAL;
+	}
+
+	init_timer(&device->lb_timeout);
+	device->lb_timeout.function = tape_long_busy_timeout;
+
+	/* Let the discipline have a go at the device. */
+	device->discipline = discipline;
+	if (!try_module_get(discipline->owner)) {
+		return -EINVAL;
+	}
+
+	rc = discipline->setup_device(device);
+	if (rc)
+		goto out;
+	rc = tape_assign_minor(device);
+	if (rc)
+		goto out_discipline;
+
+	rc = tapechar_setup_device(device);
+	if (rc)
+		goto out_minor;
+
+	tape_state_set(device, TS_UNUSED);
+
+	DBF_LH(3, "(%08x): Drive set online\n", device->cdev_id);
+
+	return 0;
+
+out_minor:
+	tape_remove_minor(device);
+out_discipline:
+	device->discipline->cleanup_device(device);
+	device->discipline = NULL;
+out:
+	module_put(discipline->owner);
+	return rc;
+}
+
+static void
+tape_cleanup_device(struct tape_device *device)
+{
+	tapechar_cleanup_device(device);
+	device->discipline->cleanup_device(device);
+	module_put(device->discipline->owner);
+	tape_remove_minor(device);
+	tape_med_state_set(device, MS_UNKNOWN);
+}
+
+/*
+ * Suspend device.
+ *
+ * Called by the common I/O layer if the drive should be suspended on user
+ * request. We refuse to suspend if the device is loaded or in use for the
+ * following reason:
+ * While the Linux guest is suspended, it might be logged off which causes
+ * devices to be detached. Tape devices are automatically rewound and unloaded
+ * during DETACH processing (unless the tape device was attached with the
+ * NOASSIGN or MULTIUSER option). After rewind/unload, there is no way to
+ * resume the original state of the tape device, since we would need to
+ * manually re-load the cartridge which was active at suspend time.
+ */
+int tape_generic_pm_suspend(struct ccw_device *cdev)
+{
+	struct tape_device *device;
+
+	device = dev_get_drvdata(&cdev->dev);
+	if (!device) {
+		return -ENODEV;
+	}
+
+	DBF_LH(3, "(%08x): tape_generic_pm_suspend(%p)\n",
+		device->cdev_id, device);
+
+	if (device->medium_state != MS_UNLOADED) {
+		pr_err("A cartridge is loaded in tape device %s, "
+		       "refusing to suspend\n", dev_name(&cdev->dev));
+		return -EBUSY;
+	}
+
+	spin_lock_irq(get_ccwdev_lock(device->cdev));
+	switch (device->tape_state) {
+		case TS_INIT:
+		case TS_NOT_OPER:
+		case TS_UNUSED:
+			spin_unlock_irq(get_ccwdev_lock(device->cdev));
+			break;
+		default:
+			pr_err("Tape device %s is busy, refusing to "
+			       "suspend\n", dev_name(&cdev->dev));
+			spin_unlock_irq(get_ccwdev_lock(device->cdev));
+			return -EBUSY;
+	}
+
+	DBF_LH(3, "(%08x): Drive suspended.\n", device->cdev_id);
+	return 0;
+}
+
+/*
+ * Set device offline.
+ *
+ * Called by the common I/O layer if the drive should set offline on user
+ * request. We may prevent this by returning an error.
+ * Manual offline is only allowed while the drive is not in use.
+ */
+int
+tape_generic_offline(struct ccw_device *cdev)
+{
+	struct tape_device *device;
+
+	device = dev_get_drvdata(&cdev->dev);
+	if (!device) {
+		return -ENODEV;
+	}
+
+	DBF_LH(3, "(%08x): tape_generic_offline(%p)\n",
+		device->cdev_id, device);
+
+	spin_lock_irq(get_ccwdev_lock(device->cdev));
+	switch (device->tape_state) {
+		case TS_INIT:
+		case TS_NOT_OPER:
+			spin_unlock_irq(get_ccwdev_lock(device->cdev));
+			break;
+		case TS_UNUSED:
+			tape_state_set(device, TS_INIT);
+			spin_unlock_irq(get_ccwdev_lock(device->cdev));
+			tape_cleanup_device(device);
+			break;
+		default:
+			DBF_EVENT(3, "(%08x): Set offline failed "
+				"- drive in use.\n",
+				device->cdev_id);
+			spin_unlock_irq(get_ccwdev_lock(device->cdev));
+			return -EBUSY;
+	}
+
+	DBF_LH(3, "(%08x): Drive set offline.\n", device->cdev_id);
+	return 0;
+}
+
+/*
+ * Allocate memory for a new device structure.
+ */
+static struct tape_device *
+tape_alloc_device(void)
+{
+	struct tape_device *device;
+
+	device = kzalloc(sizeof(struct tape_device), GFP_KERNEL);
+	if (device == NULL) {
+		DBF_EXCEPTION(2, "ti:no mem\n");
+		return ERR_PTR(-ENOMEM);
+	}
+	device->modeset_byte = kmalloc(1, GFP_KERNEL | GFP_DMA);
+	if (device->modeset_byte == NULL) {
+		DBF_EXCEPTION(2, "ti:no mem\n");
+		kfree(device);
+		return ERR_PTR(-ENOMEM);
+	}
+	mutex_init(&device->mutex);
+	INIT_LIST_HEAD(&device->req_queue);
+	INIT_LIST_HEAD(&device->node);
+	init_waitqueue_head(&device->state_change_wq);
+	init_waitqueue_head(&device->wait_queue);
+	device->tape_state = TS_INIT;
+	device->medium_state = MS_UNKNOWN;
+	*device->modeset_byte = 0;
+	device->first_minor = -1;
+	atomic_set(&device->ref_count, 1);
+	INIT_DELAYED_WORK(&device->tape_dnr, tape_delayed_next_request);
+
+	return device;
+}
+
+/*
+ * Get a reference to an existing device structure. This will automatically
+ * increment the reference count.
+ */
+struct tape_device *
+tape_get_device(struct tape_device *device)
+{
+	int count;
+
+	count = atomic_inc_return(&device->ref_count);
+	DBF_EVENT(4, "tape_get_device(%p) = %i\n", device, count);
+	return device;
+}
+
+/*
+ * Decrease the reference counter of a devices structure. If the
+ * reference counter reaches zero free the device structure.
+ * The function returns a NULL pointer to be used by the caller
+ * for clearing reference pointers.
+ */
+void
+tape_put_device(struct tape_device *device)
+{
+	int count;
+
+	count = atomic_dec_return(&device->ref_count);
+	DBF_EVENT(4, "tape_put_device(%p) -> %i\n", device, count);
+	BUG_ON(count < 0);
+	if (count == 0) {
+		kfree(device->modeset_byte);
+		kfree(device);
+	}
+}
+
+/*
+ * Find tape device by a device index.
+ */
+struct tape_device *
+tape_find_device(int devindex)
+{
+	struct tape_device *device, *tmp;
+
+	device = ERR_PTR(-ENODEV);
+	read_lock(&tape_device_lock);
+	list_for_each_entry(tmp, &tape_device_list, node) {
+		if (tmp->first_minor / TAPE_MINORS_PER_DEV == devindex) {
+			device = tape_get_device(tmp);
+			break;
+		}
+	}
+	read_unlock(&tape_device_lock);
+	return device;
+}
+
+/*
+ * Driverfs tape probe function.
+ */
+int
+tape_generic_probe(struct ccw_device *cdev)
+{
+	struct tape_device *device;
+	int ret;
+	struct ccw_dev_id dev_id;
+
+	device = tape_alloc_device();
+	if (IS_ERR(device))
+		return -ENODEV;
+	ccw_device_set_options(cdev, CCWDEV_DO_PATHGROUP |
+				     CCWDEV_DO_MULTIPATH);
+	ret = sysfs_create_group(&cdev->dev.kobj, &tape_attr_group);
+	if (ret) {
+		tape_put_device(device);
+		return ret;
+	}
+	dev_set_drvdata(&cdev->dev, device);
+	cdev->handler = __tape_do_irq;
+	device->cdev = cdev;
+	ccw_device_get_id(cdev, &dev_id);
+	device->cdev_id = devid_to_int(&dev_id);
+	return ret;
+}
+
+static void
+__tape_discard_requests(struct tape_device *device)
+{
+	struct tape_request *	request;
+	struct list_head *	l, *n;
+
+	list_for_each_safe(l, n, &device->req_queue) {
+		request = list_entry(l, struct tape_request, list);
+		if (request->status == TAPE_REQUEST_IN_IO)
+			request->status = TAPE_REQUEST_DONE;
+		list_del(&request->list);
+
+		/* Decrease ref_count for removed request. */
+		request->device = NULL;
+		tape_put_device(device);
+		request->rc = -EIO;
+		if (request->callback != NULL)
+			request->callback(request, request->callback_data);
+	}
+}
+
+/*
+ * Driverfs tape remove function.
+ *
+ * This function is called whenever the common I/O layer detects the device
+ * gone. This can happen at any time and we cannot refuse.
+ */
+void
+tape_generic_remove(struct ccw_device *cdev)
+{
+	struct tape_device *	device;
+
+	device = dev_get_drvdata(&cdev->dev);
+	if (!device) {
+		return;
+	}
+	DBF_LH(3, "(%08x): tape_generic_remove(%p)\n", device->cdev_id, cdev);
+
+	spin_lock_irq(get_ccwdev_lock(device->cdev));
+	switch (device->tape_state) {
+		case TS_INIT:
+			tape_state_set(device, TS_NOT_OPER);
+		case TS_NOT_OPER:
+			/*
+			 * Nothing to do.
+			 */
+			spin_unlock_irq(get_ccwdev_lock(device->cdev));
+			break;
+		case TS_UNUSED:
+			/*
+			 * Need only to release the device.
+			 */
+			tape_state_set(device, TS_NOT_OPER);
+			spin_unlock_irq(get_ccwdev_lock(device->cdev));
+			tape_cleanup_device(device);
+			break;
+		default:
+			/*
+			 * There may be requests on the queue. We will not get
+			 * an interrupt for a request that was running. So we
+			 * just post them all as I/O errors.
+			 */
+			DBF_EVENT(3, "(%08x): Drive in use vanished!\n",
+				device->cdev_id);
+			pr_warning("%s: A tape unit was detached while in "
+				   "use\n", dev_name(&device->cdev->dev));
+			tape_state_set(device, TS_NOT_OPER);
+			__tape_discard_requests(device);
+			spin_unlock_irq(get_ccwdev_lock(device->cdev));
+			tape_cleanup_device(device);
+	}
+
+	device = dev_get_drvdata(&cdev->dev);
+	if (device) {
+		sysfs_remove_group(&cdev->dev.kobj, &tape_attr_group);
+		dev_set_drvdata(&cdev->dev, NULL);
+		tape_put_device(device);
+	}
+}
+
+/*
+ * Allocate a new tape ccw request
+ */
+struct tape_request *
+tape_alloc_request(int cplength, int datasize)
+{
+	struct tape_request *request;
+
+	BUG_ON(datasize > PAGE_SIZE || (cplength*sizeof(struct ccw1)) > PAGE_SIZE);
+
+	DBF_LH(6, "tape_alloc_request(%d, %d)\n", cplength, datasize);
+
+	request = kzalloc(sizeof(struct tape_request), GFP_KERNEL);
+	if (request == NULL) {
+		DBF_EXCEPTION(1, "cqra nomem\n");
+		return ERR_PTR(-ENOMEM);
+	}
+	/* allocate channel program */
+	if (cplength > 0) {
+		request->cpaddr = kcalloc(cplength, sizeof(struct ccw1),
+					  GFP_ATOMIC | GFP_DMA);
+		if (request->cpaddr == NULL) {
+			DBF_EXCEPTION(1, "cqra nomem\n");
+			kfree(request);
+			return ERR_PTR(-ENOMEM);
+		}
+	}
+	/* alloc small kernel buffer */
+	if (datasize > 0) {
+		request->cpdata = kzalloc(datasize, GFP_KERNEL | GFP_DMA);
+		if (request->cpdata == NULL) {
+			DBF_EXCEPTION(1, "cqra nomem\n");
+			kfree(request->cpaddr);
+			kfree(request);
+			return ERR_PTR(-ENOMEM);
+		}
+	}
+	DBF_LH(6, "New request %p(%p/%p)\n", request, request->cpaddr,
+		request->cpdata);
+
+	return request;
+}
+
+/*
+ * Free tape ccw request
+ */
+void
+tape_free_request (struct tape_request * request)
+{
+	DBF_LH(6, "Free request %p\n", request);
+
+	if (request->device)
+		tape_put_device(request->device);
+	kfree(request->cpdata);
+	kfree(request->cpaddr);
+	kfree(request);
+}
+
+static int
+__tape_start_io(struct tape_device *device, struct tape_request *request)
+{
+	int rc;
+
+	rc = ccw_device_start(
+		device->cdev,
+		request->cpaddr,
+		(unsigned long) request,
+		0x00,
+		request->options
+	);
+	if (rc == 0) {
+		request->status = TAPE_REQUEST_IN_IO;
+	} else if (rc == -EBUSY) {
+		/* The common I/O subsystem is currently busy. Retry later. */
+		request->status = TAPE_REQUEST_QUEUED;
+		schedule_delayed_work(&device->tape_dnr, 0);
+		rc = 0;
+	} else {
+		/* Start failed. Remove request and indicate failure. */
+		DBF_EVENT(1, "tape: start request failed with RC = %i\n", rc);
+	}
+	return rc;
+}
+
+static void
+__tape_start_next_request(struct tape_device *device)
+{
+	struct list_head *l, *n;
+	struct tape_request *request;
+	int rc;
+
+	DBF_LH(6, "__tape_start_next_request(%p)\n", device);
+	/*
+	 * Try to start each request on request queue until one is
+	 * started successful.
+	 */
+	list_for_each_safe(l, n, &device->req_queue) {
+		request = list_entry(l, struct tape_request, list);
+
+		/*
+		 * Avoid race condition if bottom-half was triggered more than
+		 * once.
+		 */
+		if (request->status == TAPE_REQUEST_IN_IO)
+			return;
+		/*
+		 * Request has already been stopped. We have to wait until
+		 * the request is removed from the queue in the interrupt
+		 * handling.
+		 */
+		if (request->status == TAPE_REQUEST_DONE)
+			return;
+
+		/*
+		 * We wanted to cancel the request but the common I/O layer
+		 * was busy at that time. This can only happen if this
+		 * function is called by delayed_next_request.
+		 * Otherwise we start the next request on the queue.
+		 */
+		if (request->status == TAPE_REQUEST_CANCEL) {
+			rc = __tape_cancel_io(device, request);
+		} else {
+			rc = __tape_start_io(device, request);
+		}
+		if (rc == 0)
+			return;
+
+		/* Set ending status. */
+		request->rc = rc;
+		request->status = TAPE_REQUEST_DONE;
+
+		/* Remove from request queue. */
+		list_del(&request->list);
+
+		/* Do callback. */
+		if (request->callback != NULL)
+			request->callback(request, request->callback_data);
+	}
+}
+
+static void
+tape_delayed_next_request(struct work_struct *work)
+{
+	struct tape_device *device =
+		container_of(work, struct tape_device, tape_dnr.work);
+
+	DBF_LH(6, "tape_delayed_next_request(%p)\n", device);
+	spin_lock_irq(get_ccwdev_lock(device->cdev));
+	__tape_start_next_request(device);
+	spin_unlock_irq(get_ccwdev_lock(device->cdev));
+}
+
+static void tape_long_busy_timeout(unsigned long data)
+{
+	struct tape_request *request;
+	struct tape_device *device;
+
+	device = (struct tape_device *) data;
+	spin_lock_irq(get_ccwdev_lock(device->cdev));
+	request = list_entry(device->req_queue.next, struct tape_request, list);
+	BUG_ON(request->status != TAPE_REQUEST_LONG_BUSY);
+	DBF_LH(6, "%08x: Long busy timeout.\n", device->cdev_id);
+	__tape_start_next_request(device);
+	device->lb_timeout.data = 0UL;
+	tape_put_device(device);
+	spin_unlock_irq(get_ccwdev_lock(device->cdev));
+}
+
+static void
+__tape_end_request(
+	struct tape_device *	device,
+	struct tape_request *	request,
+	int			rc)
+{
+	DBF_LH(6, "__tape_end_request(%p, %p, %i)\n", device, request, rc);
+	if (request) {
+		request->rc = rc;
+		request->status = TAPE_REQUEST_DONE;
+
+		/* Remove from request queue. */
+		list_del(&request->list);
+
+		/* Do callback. */
+		if (request->callback != NULL)
+			request->callback(request, request->callback_data);
+	}
+
+	/* Start next request. */
+	if (!list_empty(&device->req_queue))
+		__tape_start_next_request(device);
+}
+
+/*
+ * Write sense data to dbf
+ */
+void
+tape_dump_sense_dbf(struct tape_device *device, struct tape_request *request,
+		    struct irb *irb)
+{
+	unsigned int *sptr;
+	const char* op;
+
+	if (request != NULL)
+		op = tape_op_verbose[request->op];
+	else
+		op = "---";
+	DBF_EVENT(3, "DSTAT : %02x   CSTAT: %02x\n",
+		  irb->scsw.cmd.dstat, irb->scsw.cmd.cstat);
+	DBF_EVENT(3, "DEVICE: %08x OP\t: %s\n", device->cdev_id, op);
+	sptr = (unsigned int *) irb->ecw;
+	DBF_EVENT(3, "%08x %08x\n", sptr[0], sptr[1]);
+	DBF_EVENT(3, "%08x %08x\n", sptr[2], sptr[3]);
+	DBF_EVENT(3, "%08x %08x\n", sptr[4], sptr[5]);
+	DBF_EVENT(3, "%08x %08x\n", sptr[6], sptr[7]);
+}
+
+/*
+ * I/O helper function. Adds the request to the request queue
+ * and starts it if the tape is idle. Has to be called with
+ * the device lock held.
+ */
+static int
+__tape_start_request(struct tape_device *device, struct tape_request *request)
+{
+	int rc;
+
+	switch (request->op) {
+		case TO_MSEN:
+		case TO_ASSIGN:
+		case TO_UNASSIGN:
+		case TO_READ_ATTMSG:
+		case TO_RDC:
+			if (device->tape_state == TS_INIT)
+				break;
+			if (device->tape_state == TS_UNUSED)
+				break;
+		default:
+			if (device->tape_state == TS_BLKUSE)
+				break;
+			if (device->tape_state != TS_IN_USE)
+				return -ENODEV;
+	}
+
+	/* Increase use count of device for the added request. */
+	request->device = tape_get_device(device);
+
+	if (list_empty(&device->req_queue)) {
+		/* No other requests are on the queue. Start this one. */
+		rc = __tape_start_io(device, request);
+		if (rc)
+			return rc;
+
+		DBF_LH(5, "Request %p added for execution.\n", request);
+		list_add(&request->list, &device->req_queue);
+	} else {
+		DBF_LH(5, "Request %p add to queue.\n", request);
+		request->status = TAPE_REQUEST_QUEUED;
+		list_add_tail(&request->list, &device->req_queue);
+	}
+	return 0;
+}
+
+/*
+ * Add the request to the request queue, try to start it if the
+ * tape is idle. Return without waiting for end of i/o.
+ */
+int
+tape_do_io_async(struct tape_device *device, struct tape_request *request)
+{
+	int rc;
+
+	DBF_LH(6, "tape_do_io_async(%p, %p)\n", device, request);
+
+	spin_lock_irq(get_ccwdev_lock(device->cdev));
+	/* Add request to request queue and try to start it. */
+	rc = __tape_start_request(device, request);
+	spin_unlock_irq(get_ccwdev_lock(device->cdev));
+	return rc;
+}
+
+/*
+ * tape_do_io/__tape_wake_up
+ * Add the request to the request queue, try to start it if the
+ * tape is idle and wait uninterruptible for its completion.
+ */
+static void
+__tape_wake_up(struct tape_request *request, void *data)
+{
+	request->callback = NULL;
+	wake_up((wait_queue_head_t *) data);
+}
+
+int
+tape_do_io(struct tape_device *device, struct tape_request *request)
+{
+	int rc;
+
+	spin_lock_irq(get_ccwdev_lock(device->cdev));
+	/* Setup callback */
+	request->callback = __tape_wake_up;
+	request->callback_data = &device->wait_queue;
+	/* Add request to request queue and try to start it. */
+	rc = __tape_start_request(device, request);
+	spin_unlock_irq(get_ccwdev_lock(device->cdev));
+	if (rc)
+		return rc;
+	/* Request added to the queue. Wait for its completion. */
+	wait_event(device->wait_queue, (request->callback == NULL));
+	/* Get rc from request */
+	return request->rc;
+}
+
+/*
+ * tape_do_io_interruptible/__tape_wake_up_interruptible
+ * Add the request to the request queue, try to start it if the
+ * tape is idle and wait uninterruptible for its completion.
+ */
+static void
+__tape_wake_up_interruptible(struct tape_request *request, void *data)
+{
+	request->callback = NULL;
+	wake_up_interruptible((wait_queue_head_t *) data);
+}
+
+int
+tape_do_io_interruptible(struct tape_device *device,
+			 struct tape_request *request)
+{
+	int rc;
+
+	spin_lock_irq(get_ccwdev_lock(device->cdev));
+	/* Setup callback */
+	request->callback = __tape_wake_up_interruptible;
+	request->callback_data = &device->wait_queue;
+	rc = __tape_start_request(device, request);
+	spin_unlock_irq(get_ccwdev_lock(device->cdev));
+	if (rc)
+		return rc;
+	/* Request added to the queue. Wait for its completion. */
+	rc = wait_event_interruptible(device->wait_queue,
+				      (request->callback == NULL));
+	if (rc != -ERESTARTSYS)
+		/* Request finished normally. */
+		return request->rc;
+
+	/* Interrupted by a signal. We have to stop the current request. */
+	spin_lock_irq(get_ccwdev_lock(device->cdev));
+	rc = __tape_cancel_io(device, request);
+	spin_unlock_irq(get_ccwdev_lock(device->cdev));
+	if (rc == 0) {
+		/* Wait for the interrupt that acknowledges the halt. */
+		do {
+			rc = wait_event_interruptible(
+				device->wait_queue,
+				(request->callback == NULL)
+			);
+		} while (rc == -ERESTARTSYS);
+
+		DBF_EVENT(3, "IO stopped on %08x\n", device->cdev_id);
+		rc = -ERESTARTSYS;
+	}
+	return rc;
+}
+
+/*
+ * Stop running ccw.
+ */
+int
+tape_cancel_io(struct tape_device *device, struct tape_request *request)
+{
+	int rc;
+
+	spin_lock_irq(get_ccwdev_lock(device->cdev));
+	rc = __tape_cancel_io(device, request);
+	spin_unlock_irq(get_ccwdev_lock(device->cdev));
+	return rc;
+}
+
+/*
+ * Tape interrupt routine, called from the ccw_device layer
+ */
+static void
+__tape_do_irq (struct ccw_device *cdev, unsigned long intparm, struct irb *irb)
+{
+	struct tape_device *device;
+	struct tape_request *request;
+	int rc;
+
+	device = dev_get_drvdata(&cdev->dev);
+	if (device == NULL) {
+		return;
+	}
+	request = (struct tape_request *) intparm;
+
+	DBF_LH(6, "__tape_do_irq(device=%p, request=%p)\n", device, request);
+
+	/* On special conditions irb is an error pointer */
+	if (IS_ERR(irb)) {
+		/* FIXME: What to do with the request? */
+		switch (PTR_ERR(irb)) {
+			case -ETIMEDOUT:
+				DBF_LH(1, "(%08x): Request timed out\n",
+				       device->cdev_id);
+			case -EIO:
+				__tape_end_request(device, request, -EIO);
+				break;
+			default:
+				DBF_LH(1, "(%08x): Unexpected i/o error %li\n",
+				       device->cdev_id,	PTR_ERR(irb));
+		}
+		return;
+	}
+
+	/*
+	 * If the condition code is not zero and the start function bit is
+	 * still set, this is an deferred error and the last start I/O did
+	 * not succeed. At this point the condition that caused the deferred
+	 * error might still apply. So we just schedule the request to be
+	 * started later.
+	 */
+	if (irb->scsw.cmd.cc != 0 &&
+	    (irb->scsw.cmd.fctl & SCSW_FCTL_START_FUNC) &&
+	    (request->status == TAPE_REQUEST_IN_IO)) {
+		DBF_EVENT(3,"(%08x): deferred cc=%i, fctl=%i. restarting\n",
+			device->cdev_id, irb->scsw.cmd.cc, irb->scsw.cmd.fctl);
+		request->status = TAPE_REQUEST_QUEUED;
+		schedule_delayed_work(&device->tape_dnr, HZ);
+		return;
+	}
+
+	/* May be an unsolicited irq */
+	if(request != NULL)
+		request->rescnt = irb->scsw.cmd.count;
+	else if ((irb->scsw.cmd.dstat == 0x85 || irb->scsw.cmd.dstat == 0x80) &&
+		 !list_empty(&device->req_queue)) {
+		/* Not Ready to Ready after long busy ? */
+		struct tape_request *req;
+		req = list_entry(device->req_queue.next,
+				 struct tape_request, list);
+		if (req->status == TAPE_REQUEST_LONG_BUSY) {
+			DBF_EVENT(3, "(%08x): del timer\n", device->cdev_id);
+			if (del_timer(&device->lb_timeout)) {
+				device->lb_timeout.data = 0UL;
+				tape_put_device(device);
+				__tape_start_next_request(device);
+			}
+			return;
+		}
+	}
+	if (irb->scsw.cmd.dstat != 0x0c) {
+		/* Set the 'ONLINE' flag depending on sense byte 1 */
+		if(*(((__u8 *) irb->ecw) + 1) & SENSE_DRIVE_ONLINE)
+			device->tape_generic_status |= GMT_ONLINE(~0);
+		else
+			device->tape_generic_status &= ~GMT_ONLINE(~0);
+
+		/*
+		 * Any request that does not come back with channel end
+		 * and device end is unusual. Log the sense data.
+		 */
+		DBF_EVENT(3,"-- Tape Interrupthandler --\n");
+		tape_dump_sense_dbf(device, request, irb);
+	} else {
+		/* Upon normal completion the device _is_ online */
+		device->tape_generic_status |= GMT_ONLINE(~0);
+	}
+	if (device->tape_state == TS_NOT_OPER) {
+		DBF_EVENT(6, "tape:device is not operational\n");
+		return;
+	}
+
+	/*
+	 * Request that were canceled still come back with an interrupt.
+	 * To detect these request the state will be set to TAPE_REQUEST_DONE.
+	 */
+	if(request != NULL && request->status == TAPE_REQUEST_DONE) {
+		__tape_end_request(device, request, -EIO);
+		return;
+	}
+
+	rc = device->discipline->irq(device, request, irb);
+	/*
+	 * rc < 0 : request finished unsuccessfully.
+	 * rc == TAPE_IO_SUCCESS: request finished successfully.
+	 * rc == TAPE_IO_PENDING: request is still running. Ignore rc.
+	 * rc == TAPE_IO_RETRY: request finished but needs another go.
+	 * rc == TAPE_IO_STOP: request needs to get terminated.
+	 */
+	switch (rc) {
+		case TAPE_IO_SUCCESS:
+			/* Upon normal completion the device _is_ online */
+			device->tape_generic_status |= GMT_ONLINE(~0);
+			__tape_end_request(device, request, rc);
+			break;
+		case TAPE_IO_PENDING:
+			break;
+		case TAPE_IO_LONG_BUSY:
+			device->lb_timeout.data =
+				(unsigned long) tape_get_device(device);
+			device->lb_timeout.expires = jiffies +
+				LONG_BUSY_TIMEOUT * HZ;
+			DBF_EVENT(3, "(%08x): add timer\n", device->cdev_id);
+			add_timer(&device->lb_timeout);
+			request->status = TAPE_REQUEST_LONG_BUSY;
+			break;
+		case TAPE_IO_RETRY:
+			rc = __tape_start_io(device, request);
+			if (rc)
+				__tape_end_request(device, request, rc);
+			break;
+		case TAPE_IO_STOP:
+			rc = __tape_cancel_io(device, request);
+			if (rc)
+				__tape_end_request(device, request, rc);
+			break;
+		default:
+			if (rc > 0) {
+				DBF_EVENT(6, "xunknownrc\n");
+				__tape_end_request(device, request, -EIO);
+			} else {
+				__tape_end_request(device, request, rc);
+			}
+			break;
+	}
+}
+
+/*
+ * Tape device open function used by tape_char frontend.
+ */
+int
+tape_open(struct tape_device *device)
+{
+	int rc;
+
+	spin_lock_irq(get_ccwdev_lock(device->cdev));
+	if (device->tape_state == TS_NOT_OPER) {
+		DBF_EVENT(6, "TAPE:nodev\n");
+		rc = -ENODEV;
+	} else if (device->tape_state == TS_IN_USE) {
+		DBF_EVENT(6, "TAPE:dbusy\n");
+		rc = -EBUSY;
+	} else if (device->tape_state == TS_BLKUSE) {
+		DBF_EVENT(6, "TAPE:dbusy\n");
+		rc = -EBUSY;
+	} else if (device->discipline != NULL &&
+		   !try_module_get(device->discipline->owner)) {
+		DBF_EVENT(6, "TAPE:nodisc\n");
+		rc = -ENODEV;
+	} else {
+		tape_state_set(device, TS_IN_USE);
+		rc = 0;
+	}
+	spin_unlock_irq(get_ccwdev_lock(device->cdev));
+	return rc;
+}
+
+/*
+ * Tape device release function used by tape_char frontend.
+ */
+int
+tape_release(struct tape_device *device)
+{
+	spin_lock_irq(get_ccwdev_lock(device->cdev));
+	if (device->tape_state == TS_IN_USE)
+		tape_state_set(device, TS_UNUSED);
+	module_put(device->discipline->owner);
+	spin_unlock_irq(get_ccwdev_lock(device->cdev));
+	return 0;
+}
+
+/*
+ * Execute a magnetic tape command a number of times.
+ */
+int
+tape_mtop(struct tape_device *device, int mt_op, int mt_count)
+{
+	tape_mtop_fn fn;
+	int rc;
+
+	DBF_EVENT(6, "TAPE:mtio\n");
+	DBF_EVENT(6, "TAPE:ioop: %x\n", mt_op);
+	DBF_EVENT(6, "TAPE:arg:	 %x\n", mt_count);
+
+	if (mt_op < 0 || mt_op >= TAPE_NR_MTOPS)
+		return -EINVAL;
+	fn = device->discipline->mtop_array[mt_op];
+	if (fn == NULL)
+		return -EINVAL;
+
+	/* We assume that the backends can handle count up to 500. */
+	if (mt_op == MTBSR  || mt_op == MTFSR  || mt_op == MTFSF  ||
+	    mt_op == MTBSF  || mt_op == MTFSFM || mt_op == MTBSFM) {
+		rc = 0;
+		for (; mt_count > 500; mt_count -= 500)
+			if ((rc = fn(device, 500)) != 0)
+				break;
+		if (rc == 0)
+			rc = fn(device, mt_count);
+	} else
+		rc = fn(device, mt_count);
+	return rc;
+
+}
+
+/*
+ * Tape init function.
+ */
+static int
+tape_init (void)
+{
+	TAPE_DBF_AREA = debug_register ( "tape", 2, 2, 4*sizeof(long));
+	debug_register_view(TAPE_DBF_AREA, &debug_sprintf_view);
+#ifdef DBF_LIKE_HELL
+	debug_set_level(TAPE_DBF_AREA, 6);
+#endif
+	DBF_EVENT(3, "tape init\n");
+	tape_proc_init();
+	tapechar_init ();
+	return 0;
+}
+
+/*
+ * Tape exit function.
+ */
+static void
+tape_exit(void)
+{
+	DBF_EVENT(6, "tape exit\n");
+
+	/* Get rid of the frontends */
+	tapechar_exit();
+	tape_proc_cleanup();
+	debug_unregister (TAPE_DBF_AREA);
+}
+
+MODULE_AUTHOR("(C) 2001 IBM Deutschland Entwicklung GmbH by Carsten Otte and "
+	      "Michael Holzheu (cotte@de.ibm.com,holzheu@de.ibm.com)");
+MODULE_DESCRIPTION("Linux on zSeries channel attached tape device driver");
+MODULE_LICENSE("GPL");
+
+module_init(tape_init);
+module_exit(tape_exit);
+
+EXPORT_SYMBOL(tape_generic_remove);
+EXPORT_SYMBOL(tape_generic_probe);
+EXPORT_SYMBOL(tape_generic_online);
+EXPORT_SYMBOL(tape_generic_offline);
+EXPORT_SYMBOL(tape_generic_pm_suspend);
+EXPORT_SYMBOL(tape_put_device);
+EXPORT_SYMBOL(tape_get_device);
+EXPORT_SYMBOL(tape_state_verbose);
+EXPORT_SYMBOL(tape_op_verbose);
+EXPORT_SYMBOL(tape_state_set);
+EXPORT_SYMBOL(tape_med_state_set);
+EXPORT_SYMBOL(tape_alloc_request);
+EXPORT_SYMBOL(tape_free_request);
+EXPORT_SYMBOL(tape_dump_sense_dbf);
+EXPORT_SYMBOL(tape_do_io);
+EXPORT_SYMBOL(tape_do_io_async);
+EXPORT_SYMBOL(tape_do_io_interruptible);
+EXPORT_SYMBOL(tape_cancel_io);
+EXPORT_SYMBOL(tape_mtop);