Linux-2.6.12-rc2

Initial git repository build. I'm not bothering with the full history,
even though we have it. We can create a separate "historical" git
archive of that later if we want to, and in the meantime it's about
3.2GB when imported into git - space that would just make the early
git days unnecessarily complicated, when we don't have a lot of good
infrastructure for it.

Let it rip!

1 files changed, 2065 insertions, 0 deletions

diff --git a/drivers/s390/block/dasd.c b/drivers/s390/block/dasd.c
new file mode 100644
index 00000000000..b755bac6ccb
--- /dev/null
+++ b/drivers/s390/block/dasd.c
@@ -0,0 +1,2065 @@
+/*
+ * File...........: linux/drivers/s390/block/dasd.c
+ * 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>
+ * (C) IBM Corporation, IBM Deutschland Entwicklung GmbH, 1999-2001
+ *
+ * $Revision: 1.158 $
+ */
+
+#include <linux/config.h>
+#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/buffer_head.h>
+
+#include <asm/ccwdev.h>
+#include <asm/ebcdic.h>
+#include <asm/idals.h>
+#include <asm/todclk.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;
+struct dasd_discipline *dasd_diag_discipline_pointer;
+
+MODULE_AUTHOR("Holger Smolinski <Holger.Smolinski@de.ibm.com>");
+MODULE_DESCRIPTION("Linux on S/390 DASD device driver,"
+		   " Copyright 2000 IBM Corporation");
+MODULE_SUPPORTED_DEVICE("dasd");
+MODULE_PARM(dasd, "1-" __MODULE_STRING(256) "s");
+MODULE_LICENSE("GPL");
+
+/*
+ * SECTION: prototypes for static functions of dasd.c
+ */
+static int  dasd_alloc_queue(struct dasd_device * device);
+static void dasd_setup_queue(struct dasd_device * device);
+static void dasd_free_queue(struct dasd_device * device);
+static void dasd_flush_request_queue(struct dasd_device *);
+static void dasd_int_handler(struct ccw_device *, unsigned long, struct irb *);
+static void dasd_flush_ccw_queue(struct dasd_device *, int);
+static void dasd_tasklet(struct dasd_device *);
+static void do_kick_device(void *data);
+
+/*
+ * SECTION: Operations on the device structure.
+ */
+static wait_queue_head_t dasd_init_waitq;
+
+/*
+ * Allocate memory for a new device structure.
+ */
+struct dasd_device *
+dasd_alloc_device(void)
+{
+	struct dasd_device *device;
+
+	device = kmalloc(sizeof (struct dasd_device), GFP_ATOMIC);
+	if (device == NULL)
+		return ERR_PTR(-ENOMEM);
+	memset(device, 0, sizeof (struct dasd_device));
+	/* open_count = 0 means device online but not in use */
+	atomic_set(&device->open_count, -1);
+
+	/* Get two pages for normal block device operations. */
+	device->ccw_mem = (void *) __get_free_pages(GFP_ATOMIC | GFP_DMA, 1);
+	if (device->ccw_mem == NULL) {
+		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 == NULL) {
+		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);
+	spin_lock_init(&device->request_queue_lock);
+	atomic_set (&device->tasklet_scheduled, 0);
+	tasklet_init(&device->tasklet, 
+		     (void (*)(unsigned long)) dasd_tasklet,
+		     (unsigned long) device);
+	INIT_LIST_HEAD(&device->ccw_queue);
+	init_timer(&device->timer);
+	INIT_WORK(&device->kick_work, do_kick_device, device);
+	device->state = DASD_STATE_NEW;
+	device->target = DASD_STATE_NEW;
+
+	return device;
+}
+
+/*
+ * Free memory of a device structure.
+ */
+void
+dasd_free_device(struct dasd_device *device)
+{
+	if (device->private)
+		kfree(device->private);
+	free_page((unsigned long) device->erp_mem);
+	free_pages((unsigned long) device->ccw_mem, 1);
+	kfree(device);
+}
+
+/*
+ * Make a new device known to the system.
+ */
+static inline 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);
+
+	rc = dasd_alloc_queue(device);
+	if (rc) {
+		dasd_put_device(device);
+		return rc;
+	}
+
+	device->state = DASD_STATE_KNOWN;
+	return 0;
+}
+
+/*
+ * Let the system forget about a device.
+ */
+static inline void
+dasd_state_known_to_new(struct dasd_device * device)
+{
+	/* Forget the discipline information. */
+	device->discipline = NULL;
+	device->state = DASD_STATE_NEW;
+
+	dasd_free_queue(device);
+
+	/* Give up reference we took in dasd_state_new_to_known. */
+	dasd_put_device(device);
+}
+
+/*
+ * Request the irq line for the device.
+ */
+static inline int
+dasd_state_known_to_basic(struct dasd_device * device)
+{
+	int rc;
+
+	/* Allocate and register gendisk structure. */
+	rc = dasd_gendisk_alloc(device);
+	if (rc)
+		return rc;
+
+	/* register 'device' debug area, used for all DBF_DEV_XXX calls */
+	device->debug_area = debug_register(device->cdev->dev.bus_id, 0, 2,
+					    8 * sizeof (long));
+	debug_register_view(device->debug_area, &debug_sprintf_view);
+	debug_set_level(device->debug_area, DBF_EMERG);
+	DBF_DEV_EVENT(DBF_EMERG, device, "%s", "debug area created");
+
+	device->state = DASD_STATE_BASIC;
+	return 0;
+}
+
+/*
+ * Release the irq line for the device. Terminate any running i/o.
+ */
+static inline void
+dasd_state_basic_to_known(struct dasd_device * device)
+{
+	dasd_gendisk_free(device);
+	dasd_flush_ccw_queue(device, 1);
+	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;
+}
+
+/*
+ * 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 or error)
+ * the block device is setup. Either a fake disk is added to allow
+ * formatting or a proper device request queue is created.
+ */
+static inline int
+dasd_state_basic_to_ready(struct dasd_device * device)
+{
+	int rc;
+
+	rc = 0;
+	if (device->discipline->do_analysis != NULL)
+		rc = device->discipline->do_analysis(device);
+	if (rc)
+		return rc;
+	dasd_setup_queue(device);
+	device->state = DASD_STATE_READY;
+	if (dasd_scan_partitions(device) != 0)
+		device->state = DASD_STATE_BASIC;
+	return 0;
+}
+
+/*
+ * 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 inline void
+dasd_state_ready_to_basic(struct dasd_device * device)
+{
+	dasd_flush_ccw_queue(device, 0);
+	dasd_destroy_partitions(device);
+	dasd_flush_request_queue(device);
+	device->blocks = 0;
+	device->bp_block = 0;
+	device->s2b_shift = 0;
+	device->state = DASD_STATE_BASIC;
+}
+
+/*
+ * 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 inline int
+dasd_state_ready_to_online(struct dasd_device * device)
+{
+	device->state = DASD_STATE_ONLINE;
+	dasd_schedule_bh(device);
+	return 0;
+}
+
+/*
+ * Stop the requeueing of requests again.
+ */
+static inline void
+dasd_state_online_to_ready(struct dasd_device * device)
+{
+	device->state = DASD_STATE_READY;
+}
+
+/*
+ * Device startup state changes.
+ */
+static inline 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_READY &&
+	    device->target >= DASD_STATE_ONLINE)
+		rc = dasd_state_ready_to_online(device);
+
+	return rc;
+}
+
+/*
+ * Device shutdown state changes.
+ */
+static inline int
+dasd_decrease_state(struct dasd_device *device)
+{
+	if (device->state == DASD_STATE_ONLINE &&
+	    device->target <= DASD_STATE_READY)
+		dasd_state_online_to_ready(device);
+	
+	if (device->state == DASD_STATE_READY &&
+	    device->target <= DASD_STATE_BASIC)
+		dasd_state_ready_to_basic(device);
+	
+	if (device->state == DASD_STATE_BASIC && 
+	    device->target <= DASD_STATE_KNOWN)
+		dasd_state_basic_to_known(device);
+	
+	if (device->state == DASD_STATE_KNOWN &&
+	    device->target <= DASD_STATE_NEW)
+		dasd_state_known_to_new(device);
+
+	return 0;
+}
+
+/*
+ * 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 && rc != -EAGAIN)
+                device->target = device->state;
+
+	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(void *data)
+{
+	struct dasd_device *device;
+
+	device = (struct dasd_device *) data;
+	dasd_change_state(device);
+	dasd_schedule_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. */
+	schedule_work(&device->kick_work);
+}
+
+/*
+ * Set the target state for a device and starts the state change.
+ */
+void
+dasd_set_target_state(struct dasd_device *device, int target)
+{
+	/* 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);
+}
+
+/*
+ * 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));
+}
+
+/*
+ * SECTION: device operation (interrupt handler, start i/o, term i/o ...)
+ */
+#ifdef CONFIG_DASD_PROFILE
+
+struct dasd_profile_info_t dasd_global_profile;
+unsigned int dasd_profile_level = DASD_PROFILE_OFF;
+
+/*
+ * Increments counter in global and local profiling structures.
+ */
+#define dasd_profile_counter(value, counter, device) \
+{ \
+	int index; \
+	for (index = 0; index < 31 && value >> (2+index); index++); \
+	dasd_global_profile.counter[index]++; \
+	device->profile.counter[index]++; \
+}
+
+/*
+ * Add profiling information for cqr before execution.
+ */
+static inline void
+dasd_profile_start(struct dasd_device *device, struct dasd_ccw_req * cqr,
+		   struct request *req)
+{
+	struct list_head *l;
+	unsigned int counter;
+
+	if (dasd_profile_level != DASD_PROFILE_ON)
+		return;
+
+	/* count the length of the chanq for statistics */
+	counter = 0;
+	list_for_each(l, &device->ccw_queue)
+		if (++counter >= 31)
+			break;
+	dasd_global_profile.dasd_io_nr_req[counter]++;
+	device->profile.dasd_io_nr_req[counter]++;
+}
+
+/*
+ * Add profiling information for cqr after execution.
+ */
+static inline void
+dasd_profile_end(struct dasd_device *device, struct dasd_ccw_req * cqr,
+		 struct request *req)
+{
+	long strtime, irqtime, endtime, tottime;	/* in microseconds */
+	long tottimeps, sectors;
+
+	if (dasd_profile_level != DASD_PROFILE_ON)
+		return;
+
+	sectors = req->nr_sectors;
+	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;
+
+	if (!dasd_global_profile.dasd_io_reqs)
+		memset(&dasd_global_profile, 0,
+		       sizeof (struct dasd_profile_info_t));
+	dasd_global_profile.dasd_io_reqs++;
+	dasd_global_profile.dasd_io_sects += sectors;
+
+	if (!device->profile.dasd_io_reqs)
+		memset(&device->profile, 0,
+		       sizeof (struct dasd_profile_info_t));
+	device->profile.dasd_io_reqs++;
+	device->profile.dasd_io_sects += sectors;
+
+	dasd_profile_counter(sectors, dasd_io_secs, device);
+	dasd_profile_counter(tottime, dasd_io_times, device);
+	dasd_profile_counter(tottimeps, dasd_io_timps, device);
+	dasd_profile_counter(strtime, dasd_io_time1, device);
+	dasd_profile_counter(irqtime, dasd_io_time2, device);
+	dasd_profile_counter(irqtime / sectors, dasd_io_time2ps, device);
+	dasd_profile_counter(endtime, dasd_io_time3, device);
+}
+#else
+#define dasd_profile_start(device, cqr, req) do {} while (0)
+#define dasd_profile_end(device, cqr, req) do {} while (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(char *magic, int cplength, int datasize,
+		   struct dasd_device * device)
+{
+	struct dasd_ccw_req *cqr;
+
+	/* Sanity checks */
+	if ( magic == NULL || datasize > PAGE_SIZE ||
+	     (cplength*sizeof(struct ccw1)) > PAGE_SIZE)
+		BUG();
+
+	cqr = kmalloc(sizeof(struct dasd_ccw_req), GFP_ATOMIC);
+	if (cqr == NULL)
+		return ERR_PTR(-ENOMEM);
+	memset(cqr, 0, sizeof(struct dasd_ccw_req));
+	cqr->cpaddr = NULL;
+	if (cplength > 0) {
+		cqr->cpaddr = kmalloc(cplength*sizeof(struct ccw1),
+				      GFP_ATOMIC | GFP_DMA);
+		if (cqr->cpaddr == NULL) {
+			kfree(cqr);
+			return ERR_PTR(-ENOMEM);
+		}
+		memset(cqr->cpaddr, 0, cplength*sizeof(struct ccw1));
+	}
+	cqr->data = NULL;
+	if (datasize > 0) {
+		cqr->data = kmalloc(datasize, GFP_ATOMIC | GFP_DMA);
+		if (cqr->data == NULL) {
+			if (cqr->cpaddr != NULL)
+				kfree(cqr->cpaddr);
+			kfree(cqr);
+			return ERR_PTR(-ENOMEM);
+		}
+		memset(cqr->data, 0, datasize);
+	}
+	strncpy((char *) &cqr->magic, magic, 4);
+	ASCEBC((char *) &cqr->magic, 4);
+	set_bit(DASD_CQR_FLAGS_USE_ERP, &cqr->flags);
+	dasd_get_device(device);
+	return cqr;
+}
+
+struct dasd_ccw_req *
+dasd_smalloc_request(char *magic, int cplength, int datasize,
+		   struct dasd_device * device)
+{
+	unsigned long flags;
+	struct dasd_ccw_req *cqr;
+	char *data;
+	int size;
+
+	/* Sanity checks */
+	if ( magic == NULL || datasize > PAGE_SIZE ||
+	     (cplength*sizeof(struct ccw1)) > PAGE_SIZE)
+		BUG();
+
+	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);
+	}
+	strncpy((char *) &cqr->magic, magic, 4);
+	ASCEBC((char *) &cqr->magic, 4);
+	set_bit(DASD_CQR_FLAGS_USE_ERP, &cqr->flags);
+	dasd_get_device(device);
+	return cqr;
+}
+
+/*
+ * 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)
+{
+#ifdef CONFIG_ARCH_S390X
+	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));
+#endif
+	if (cqr->cpaddr != NULL)
+		kfree(cqr->cpaddr);
+	if (cqr->data != NULL)
+		kfree(cqr->data);
+	kfree(cqr);
+	dasd_put_device(device);
+}
+
+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);
+}
+
+/*
+ * 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->device;
+	if (strncmp((char *) &cqr->magic, device->discipline->ebcname, 4)) {
+		DEV_MESSAGE(KERN_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;
+
+	/* Check the cqr */
+	rc = dasd_check_cqr(cqr);
+	if (rc)
+		return rc;
+	retries = 0;
+	device = (struct dasd_device *) cqr->device;
+	while ((retries < 5) && (cqr->status == DASD_CQR_IN_IO)) {
+		rc = ccw_device_clear(device->cdev, (long) cqr);
+		switch (rc) {
+		case 0:	/* termination successful */
+		        if (cqr->retries > 0) {
+				cqr->retries--;
+				cqr->status = DASD_CQR_CLEAR;
+			} else
+				cqr->status = DASD_CQR_FAILED;
+			cqr->stopclk = get_clock();
+			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:
+		case -EBUSY:
+			DBF_DEV_EVENT(DBF_ERR, device, "%s",
+				      "device busy, retry later");
+			break;
+		default:
+			DEV_MESSAGE(KERN_ERR, device,
+				    "line %d unknown RC=%d, please "
+				    "report to linux390@de.ibm.com",
+				    __LINE__, rc);
+			BUG();
+			break;
+		}
+		retries++;
+	}
+	dasd_schedule_bh(device);
+	return rc;
+}
+
+/*
+ * 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;
+
+	/* Check the cqr */
+	rc = dasd_check_cqr(cqr);
+	if (rc)
+		return rc;
+	device = (struct dasd_device *) cqr->device;
+	if (cqr->retries < 0) {
+		DEV_MESSAGE(KERN_DEBUG, device,
+			    "start_IO: request %p (%02x/%i) - no retry left.",
+			    cqr, cqr->status, cqr->retries);
+		cqr->status = DASD_CQR_FAILED;
+		return -EIO;
+	}
+	cqr->startclk = get_clock();
+	cqr->starttime = jiffies;
+	cqr->retries--;
+	rc = ccw_device_start(device->cdev, cqr->cpaddr, (long) cqr,
+			      cqr->lpm, 0);
+	switch (rc) {
+	case 0:
+		cqr->status = DASD_CQR_IN_IO;
+		DBF_DEV_EVENT(DBF_DEBUG, device,
+			      "start_IO: request %p started successful",
+			      cqr);
+		break;
+	case -EBUSY:
+		DBF_DEV_EVENT(DBF_ERR, device, "%s",
+			      "start_IO: device busy, retry later");
+		break;
+	case -ETIMEDOUT:
+		DBF_DEV_EVENT(DBF_ERR, device, "%s",
+			      "start_IO: request timeout, retry later");
+		break;
+	case -EACCES:
+		/* -EACCES indicates that the request used only a
+		 * subset of the available pathes and all these
+		 * pathes are gone.
+		 * Do a retry with all available pathes.
+		 */
+		cqr->lpm = LPM_ANYPATH;
+		DBF_DEV_EVENT(DBF_ERR, device, "%s",
+			      "start_IO: selected pathes gone,"
+			      " retry on all pathes");
+		break;
+	case -ENODEV:
+	case -EIO:
+		DBF_DEV_EVENT(DBF_ERR, device, "%s",
+			      "start_IO: device gone, retry");
+		break;
+	default:
+		DEV_MESSAGE(KERN_ERR, device,
+			    "line %d unknown RC=%d, please report"
+			    " to linux390@de.ibm.com", __LINE__, rc);
+		BUG();
+		break;
+	}
+	return rc;
+}
+
+/*
+ * 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_timeout_device(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 */
+        device->stopped &= ~DASD_STOPPED_PENDING;
+	spin_unlock_irqrestore(get_ccwdev_lock(device->cdev), flags);
+	dasd_schedule_bh(device);
+}
+
+/*
+ * Setup timeout for a device in jiffies.
+ */
+void
+dasd_set_timer(struct dasd_device *device, int expires)
+{
+	if (expires == 0) {
+		if (timer_pending(&device->timer))
+			del_timer(&device->timer);
+		return;
+	}
+	if (timer_pending(&device->timer)) {
+		if (mod_timer(&device->timer, jiffies + expires))
+			return;
+	}
+	device->timer.function = dasd_timeout_device;
+	device->timer.data = (unsigned long) device;
+	device->timer.expires = jiffies + expires;
+	add_timer(&device->timer);
+}
+
+/*
+ * Clear timeout for a device.
+ */
+void
+dasd_clear_timer(struct dasd_device *device)
+{
+	if (timer_pending(&device->timer))
+		del_timer(&device->timer);
+}
+
+static void
+dasd_handle_killed_request(struct ccw_device *cdev, unsigned long intparm)
+{
+	struct dasd_ccw_req *cqr;
+	struct dasd_device *device;
+
+	cqr = (struct dasd_ccw_req *) intparm;
+	if (cqr->status != DASD_CQR_IN_IO) {
+		MESSAGE(KERN_DEBUG,
+			"invalid status in handle_killed_request: "
+			"bus_id %s, status %02x",
+			cdev->dev.bus_id, cqr->status);
+		return;
+	}
+
+	device = (struct dasd_device *) cqr->device;
+	if (device == NULL ||
+	    device != dasd_device_from_cdev(cdev) ||
+	    strncmp(device->discipline->ebcname, (char *) &cqr->magic, 4)) {
+		MESSAGE(KERN_DEBUG, "invalid device in request: bus_id %s",
+			cdev->dev.bus_id);
+		return;
+	}
+
+	/* Schedule request to be retried. */
+	cqr->status = DASD_CQR_QUEUED;
+
+	dasd_clear_timer(device);
+	dasd_schedule_bh(device);
+	dasd_put_device(device);
+}
+
+static void
+dasd_handle_state_change_pending(struct dasd_device *device)
+{
+	struct dasd_ccw_req *cqr;
+	struct list_head *l, *n;
+
+	device->stopped &= ~DASD_STOPPED_PENDING;
+
+        /* restart all 'running' IO on queue */
+	list_for_each_safe(l, n, &device->ccw_queue) {
+		cqr = list_entry(l, struct dasd_ccw_req, list);
+                if (cqr->status == DASD_CQR_IN_IO) {
+                        cqr->status = DASD_CQR_QUEUED;
+		}
+        }
+	dasd_clear_timer(device);
+	dasd_schedule_bh(device);
+}
+
+/*
+ * 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;
+	dasd_era_t era;
+	char mask;
+
+	if (IS_ERR(irb)) {
+		switch (PTR_ERR(irb)) {
+		case -EIO:
+			dasd_handle_killed_request(cdev, intparm);
+			break;
+		case -ETIMEDOUT:
+			printk(KERN_WARNING"%s(%s): request timed out\n",
+			       __FUNCTION__, cdev->dev.bus_id);
+			//FIXME - dasd uses own timeout interface...
+			break;
+		default:
+			printk(KERN_WARNING"%s(%s): unknown error %ld\n",
+			       __FUNCTION__, cdev->dev.bus_id, PTR_ERR(irb));
+		}
+		return;
+	}
+
+	now = get_clock();
+
+	DBF_EVENT(DBF_ERR, "Interrupt: bus_id %s CS/DS %04x ip %08x",
+		  cdev->dev.bus_id, ((irb->scsw.cstat<<8)|irb->scsw.dstat),
+		  (unsigned int) intparm);
+
+	/* first of all check for state change pending interrupt */
+	mask = DEV_STAT_ATTENTION | DEV_STAT_DEV_END | DEV_STAT_UNIT_EXCEP;
+	if ((irb->scsw.dstat & mask) == mask) {
+		device = dasd_device_from_cdev(cdev);
+		if (!IS_ERR(device)) {
+			dasd_handle_state_change_pending(device);
+			dasd_put_device(device);
+		}
+		return;
+	}
+
+	cqr = (struct dasd_ccw_req *) intparm;
+
+	/* check for unsolicited interrupts */
+	if (cqr == NULL) {
+		MESSAGE(KERN_DEBUG,
+			"unsolicited interrupt received: bus_id %s",
+			cdev->dev.bus_id);
+		return;
+	}
+
+	device = (struct dasd_device *) cqr->device;
+	if (device == NULL ||
+	    strncmp(device->discipline->ebcname, (char *) &cqr->magic, 4)) {
+		MESSAGE(KERN_DEBUG, "invalid device in request: bus_id %s",
+			cdev->dev.bus_id);
+		return;
+	}
+
+	/* Check for clear pending */
+	if (cqr->status == DASD_CQR_CLEAR &&
+	    irb->scsw.fctl & SCSW_FCTL_CLEAR_FUNC) {
+		cqr->status = DASD_CQR_QUEUED;
+		dasd_clear_timer(device);
+		dasd_schedule_bh(device);
+		return;
+	}
+
+ 	/* check status - the request might have been killed by dyn detach */
+	if (cqr->status != DASD_CQR_IN_IO) {
+		MESSAGE(KERN_DEBUG,
+			"invalid status: bus_id %s, status %02x",
+			cdev->dev.bus_id, cqr->status);
+		return;
+	}
+	DBF_DEV_EVENT(DBF_DEBUG, device, "Int: CS/DS 0x%04x for cqr %p",
+		      ((irb->scsw.cstat << 8) | irb->scsw.dstat), cqr);
+
+ 	/* Find out the appropriate era_action. */
+	if (irb->scsw.fctl & SCSW_FCTL_HALT_FUNC) 
+		era = dasd_era_fatal;
+	else if (irb->scsw.dstat == (DEV_STAT_CHN_END | DEV_STAT_DEV_END) &&
+		 irb->scsw.cstat == 0 &&
+		 !irb->esw.esw0.erw.cons)
+		era = dasd_era_none;
+	else if (!test_bit(DASD_CQR_FLAGS_USE_ERP, &cqr->flags))
+ 	        era = dasd_era_fatal; /* don't recover this request */
+	else if (irb->esw.esw0.erw.cons)
+		era = device->discipline->examine_error(cqr, irb);
+	else 
+		era = dasd_era_recover;
+
+	DBF_DEV_EVENT(DBF_DEBUG, device, "era_code %d", era);
+	expires = 0;
+	if (era == dasd_era_none) {
+		cqr->status = DASD_CQR_DONE;
+		cqr->stopclk = now;
+		/* Start first request on queue if possible -> fast_io. */
+		if (cqr->list.next != &device->ccw_queue) {
+			next = list_entry(cqr->list.next,
+					  struct dasd_ccw_req, list);
+			if ((next->status == DASD_CQR_QUEUED) &&
+			    (!device->stopped)) {
+				if (device->discipline->start_IO(next) == 0)
+					expires = next->expires;
+				else
+					DEV_MESSAGE(KERN_DEBUG, device, "%s",
+						    "Interrupt fastpath "
+						    "failed!");
+			}
+		}
+	} else {		/* error */
+		memcpy(&cqr->irb, irb, sizeof (struct irb));
+#ifdef ERP_DEBUG
+		/* dump sense data */
+		dasd_log_sense(cqr, irb);
+#endif
+		switch (era) {
+		case dasd_era_fatal:
+			cqr->status = DASD_CQR_FAILED;
+			cqr->stopclk = now;
+			break;
+		case dasd_era_recover:
+			cqr->status = DASD_CQR_ERROR;
+			break;
+		default:
+			BUG();
+		}
+	}
+	if (expires != 0)
+		dasd_set_timer(device, expires);
+	else
+		dasd_clear_timer(device);
+	dasd_schedule_bh(device);
+}
+
+/*
+ * posts the buffer_cache about a finalized request
+ */
+static inline void
+dasd_end_request(struct request *req, int uptodate)
+{
+	if (end_that_request_first(req, uptodate, req->hard_nr_sectors))
+		BUG();
+	add_disk_randomness(req->rq_disk);
+	end_that_request_last(req);
+}
+
+/*
+ * Process finished error recovery ccw.
+ */
+static inline 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_MESSAGE(KERN_ERR, device, "%s", "ERP unsuccessful");
+	erp_fn = device->discipline->erp_postaction(cqr);
+	erp_fn(cqr);
+}
+
+/*
+ * Process ccw request queue.
+ */
+static inline void
+__dasd_process_ccw_queue(struct dasd_device * device,
+			 struct list_head *final_queue)
+{
+	struct list_head *l, *n;
+	struct dasd_ccw_req *cqr;
+	dasd_erp_fn_t erp_fn;
+
+restart:
+	/* Process request with final status. */
+	list_for_each_safe(l, n, &device->ccw_queue) {
+		cqr = list_entry(l, struct dasd_ccw_req, list);
+		/* Stop list processing at the first non-final request. */
+		if (cqr->status != DASD_CQR_DONE &&
+		    cqr->status != DASD_CQR_FAILED &&
+		    cqr->status != DASD_CQR_ERROR)
+			break;
+		/*  Process requests with DASD_CQR_ERROR */
+		if (cqr->status == DASD_CQR_ERROR) {
+			if (cqr->irb.scsw.fctl & SCSW_FCTL_HALT_FUNC) {
+				cqr->status = DASD_CQR_FAILED;
+				cqr->stopclk = get_clock();
+			} else {
+				if (cqr->irb.esw.esw0.erw.cons) {
+					erp_fn = device->discipline->
+						erp_action(cqr);
+					erp_fn(cqr);
+				} else
+					dasd_default_erp_action(cqr);
+			}
+			goto restart;
+		}
+		/* Process finished ERP request. */
+		if (cqr->refers) {
+			__dasd_process_erp(device, cqr);
+			goto restart;
+		}
+
+		/* Rechain finished requests to final queue */
+		cqr->endclk = get_clock();
+		list_move_tail(&cqr->list, final_queue);
+	}
+}
+
+static void
+dasd_end_request_cb(struct dasd_ccw_req * cqr, void *data)
+{
+	struct request *req;
+	struct dasd_device *device;
+	int status;
+
+	req = (struct request *) data;
+	device = cqr->device;
+	dasd_profile_end(device, cqr, req);
+	status = cqr->device->discipline->free_cp(cqr,req);
+	spin_lock_irq(&device->request_queue_lock);
+	dasd_end_request(req, status);
+	spin_unlock_irq(&device->request_queue_lock);
+}
+
+
+/*
+ * Fetch requests from the block device queue.
+ */
+static inline void
+__dasd_process_blk_queue(struct dasd_device * device)
+{
+	request_queue_t *queue;
+	struct request *req;
+	struct dasd_ccw_req *cqr;
+	int nr_queued;
+
+	queue = device->request_queue;
+	/* 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 (device->state != DASD_STATE_READY &&
+	    device->state != DASD_STATE_ONLINE)
+		return;
+	nr_queued = 0;
+	/* Now we try to fetch requests from the request queue */
+	list_for_each_entry(cqr, &device->ccw_queue, list)
+		if (cqr->status == DASD_CQR_QUEUED)
+			nr_queued++;
+	while (!blk_queue_plugged(queue) &&
+	       elv_next_request(queue) &&
+		nr_queued < DASD_CHANQ_MAX_SIZE) {
+		req = elv_next_request(queue);
+		if (test_bit(DASD_FLAG_RO, &device->flags) &&
+		    rq_data_dir(req) == WRITE) {
+			DBF_DEV_EVENT(DBF_ERR, device,
+				      "Rejecting write request %p",
+				      req);
+			blkdev_dequeue_request(req);
+			dasd_end_request(req, 0);
+			continue;
+		}
+		if (device->stopped & DASD_STOPPED_DC_EIO) {
+			blkdev_dequeue_request(req);
+			dasd_end_request(req, 0);
+			continue;
+		}
+		cqr = device->discipline->build_cp(device, req);
+		if (IS_ERR(cqr)) {
+			if (PTR_ERR(cqr) == -ENOMEM)
+				break;	/* terminate request queue loop */
+			DBF_DEV_EVENT(DBF_ERR, device,
+				      "CCW creation failed (rc=%ld) "
+				      "on request %p",
+				      PTR_ERR(cqr), req);
+			blkdev_dequeue_request(req);
+			dasd_end_request(req, 0);
+			continue;
+		}
+		cqr->callback = dasd_end_request_cb;
+		cqr->callback_data = (void *) req;
+		cqr->status = DASD_CQR_QUEUED;
+		blkdev_dequeue_request(req);
+		list_add_tail(&cqr->list, &device->ccw_queue);
+		dasd_profile_start(device, cqr, req);
+		nr_queued++;
+	}
+}
+
+/*
+ * 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 inline void
+__dasd_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, list);
+	if (cqr->status == DASD_CQR_IN_IO && cqr->expires != 0) {
+		if (time_after_eq(jiffies, cqr->expires + cqr->starttime)) {
+			if (device->discipline->term_IO(cqr) != 0)
+				/* Hmpf, try again in 1/10 sec */
+				dasd_set_timer(device, 10);
+		}
+	}
+}
+
+/*
+ * Take a look at the first request on the ccw queue and check
+ * if it needs to be started.
+ */
+static inline void
+__dasd_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, list);
+	if ((cqr->status == DASD_CQR_QUEUED) &&
+	    (!device->stopped)) {
+		/* try to start the first I/O that can be started */
+		rc = device->discipline->start_IO(cqr);
+		if (rc == 0)
+			dasd_set_timer(device, cqr->expires);
+		else if (rc == -EACCES) {
+			dasd_schedule_bh(device);
+		} else
+			/* Hmpf, try again in 1/2 sec */
+			dasd_set_timer(device, 50);
+	}
+}
+
+/*
+ * Remove requests from the ccw queue. 
+ */
+static void
+dasd_flush_ccw_queue(struct dasd_device * device, int all)
+{
+	struct list_head flush_queue;
+	struct list_head *l, *n;
+	struct dasd_ccw_req *cqr;
+
+	INIT_LIST_HEAD(&flush_queue);
+	spin_lock_irq(get_ccwdev_lock(device->cdev));
+	list_for_each_safe(l, n, &device->ccw_queue) {
+		cqr = list_entry(l, struct dasd_ccw_req, list);
+		/* Flush all request or only block device requests? */
+		if (all == 0 && cqr->callback == dasd_end_request_cb)
+			continue;
+		if (cqr->status == DASD_CQR_IN_IO)
+			device->discipline->term_IO(cqr);
+		if (cqr->status != DASD_CQR_DONE ||
+		    cqr->status != DASD_CQR_FAILED) {
+			cqr->status = DASD_CQR_FAILED;
+			cqr->stopclk = get_clock();
+		}
+		/* Process finished ERP request. */
+		if (cqr->refers) {
+			__dasd_process_erp(device, cqr);
+			continue;
+		}
+		/* Rechain request on device request queue */
+		cqr->endclk = get_clock();
+		list_move_tail(&cqr->list, &flush_queue);
+	}
+	spin_unlock_irq(get_ccwdev_lock(device->cdev));
+	/* Now call the callback function of flushed requests */
+	list_for_each_safe(l, n, &flush_queue) {
+		cqr = list_entry(l, struct dasd_ccw_req, list);
+		if (cqr->callback != NULL)
+			(cqr->callback)(cqr, cqr->callback_data);
+	}
+}
+
+/*
+ * Acquire the device lock and process queues for the device.
+ */
+static void
+dasd_tasklet(struct dasd_device * device)
+{
+	struct list_head final_queue;
+	struct list_head *l, *n;
+	struct dasd_ccw_req *cqr;
+
+	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_check_expire(device);
+	/* Finish off requests on ccw queue */
+	__dasd_process_ccw_queue(device, &final_queue);
+	spin_unlock_irq(get_ccwdev_lock(device->cdev));
+	/* Now call the callback function of requests with final status */
+	list_for_each_safe(l, n, &final_queue) {
+		cqr = list_entry(l, struct dasd_ccw_req, list);
+		list_del(&cqr->list);
+		if (cqr->callback != NULL)
+			(cqr->callback)(cqr, cqr->callback_data);
+	}
+	spin_lock_irq(&device->request_queue_lock);
+	spin_lock(get_ccwdev_lock(device->cdev));
+	/* Get new request from the block device request queue */
+	__dasd_process_blk_queue(device);
+	/* Now check if the head of the ccw queue needs to be started. */
+	__dasd_start_head(device);
+	spin_unlock(get_ccwdev_lock(device->cdev));
+	spin_unlock_irq(&device->request_queue_lock);
+	dasd_put_device(device);
+}
+
+/*
+ * Schedules a call to dasd_tasklet over the device tasklet.
+ */
+void
+dasd_schedule_bh(struct dasd_device * device)
+{
+	/* Protect against rescheduling. */
+	if (atomic_compare_and_swap (0, 1, &device->tasklet_scheduled))
+		return;
+	dasd_get_device(device);
+	tasklet_hi_schedule(&device->tasklet);
+}
+
+/*
+ * Queue a request to the head of the ccw_queue. Start the I/O if
+ * possible.
+ */
+void
+dasd_add_request_head(struct dasd_ccw_req *req)
+{
+	struct dasd_device *device;
+	unsigned long flags;
+
+	device = req->device;
+	spin_lock_irqsave(get_ccwdev_lock(device->cdev), flags);
+	req->status = DASD_CQR_QUEUED;
+	req->device = device;
+	list_add(&req->list, &device->ccw_queue);
+	/* let the bh start the request to keep them in order */
+	dasd_schedule_bh(device);
+	spin_unlock_irqrestore(get_ccwdev_lock(device->cdev), flags);
+}
+
+/*
+ * Queue a request to the tail of the ccw_queue. Start the I/O if
+ * possible.
+ */
+void
+dasd_add_request_tail(struct dasd_ccw_req *req)
+{
+	struct dasd_device *device;
+	unsigned long flags;
+
+	device = req->device;
+	spin_lock_irqsave(get_ccwdev_lock(device->cdev), flags);
+	req->status = DASD_CQR_QUEUED;
+	req->device = device;
+	list_add_tail(&req->list, &device->ccw_queue);
+	/* let the bh start the request to keep them in order */
+	dasd_schedule_bh(device);
+	spin_unlock_irqrestore(get_ccwdev_lock(device->cdev), flags);
+}
+
+/*
+ * Wakeup callback.
+ */
+static void
+dasd_wakeup_cb(struct dasd_ccw_req *cqr, void *data)
+{
+	wake_up((wait_queue_head_t *) data);
+}
+
+static inline int
+_wait_for_wakeup(struct dasd_ccw_req *cqr)
+{
+	struct dasd_device *device;
+	int rc;
+
+	device = cqr->device;
+	spin_lock_irq(get_ccwdev_lock(device->cdev));
+	rc = cqr->status == DASD_CQR_DONE || cqr->status == DASD_CQR_FAILED;
+	spin_unlock_irq(get_ccwdev_lock(device->cdev));
+	return rc;
+}
+
+/*
+ * Attempts to start a special ccw queue and waits for its completion.
+ */
+int
+dasd_sleep_on(struct dasd_ccw_req * cqr)
+{
+	wait_queue_head_t wait_q;
+	struct dasd_device *device;
+	int rc;
+	
+	device = cqr->device;
+	spin_lock_irq(get_ccwdev_lock(device->cdev));
+	
+	init_waitqueue_head (&wait_q);
+	cqr->callback = dasd_wakeup_cb;
+	cqr->callback_data = (void *) &wait_q;
+	cqr->status = DASD_CQR_QUEUED;
+	list_add_tail(&cqr->list, &device->ccw_queue);
+	
+	/* let the bh start the request to keep them in order */
+	dasd_schedule_bh(device);
+	
+	spin_unlock_irq(get_ccwdev_lock(device->cdev));
+
+	wait_event(wait_q, _wait_for_wakeup(cqr));
+	
+	/* Request status is either done or failed. */
+	rc = (cqr->status == DASD_CQR_FAILED) ? -EIO : 0;
+	return rc;
+}
+
+/*
+ * Attempts to start a special ccw queue and wait interruptible
+ * for its completion.
+ */
+int
+dasd_sleep_on_interruptible(struct dasd_ccw_req * cqr)
+{
+	wait_queue_head_t wait_q;
+	struct dasd_device *device;
+	int rc, finished;
+
+	device = cqr->device;
+	spin_lock_irq(get_ccwdev_lock(device->cdev));
+
+	init_waitqueue_head (&wait_q);
+	cqr->callback = dasd_wakeup_cb;
+	cqr->callback_data = (void *) &wait_q;
+	cqr->status = DASD_CQR_QUEUED;
+	list_add_tail(&cqr->list, &device->ccw_queue);
+
+	/* let the bh start the request to keep them in order */
+	dasd_schedule_bh(device);
+	spin_unlock_irq(get_ccwdev_lock(device->cdev));
+
+	finished = 0;
+	while (!finished) {
+		rc = wait_event_interruptible(wait_q, _wait_for_wakeup(cqr));
+		if (rc != -ERESTARTSYS) {
+			/* Request status is either done or failed. */
+			rc = (cqr->status == DASD_CQR_FAILED) ? -EIO : 0;
+			break;
+		}
+		spin_lock_irq(get_ccwdev_lock(device->cdev));
+		if (cqr->status == DASD_CQR_IN_IO &&
+		    device->discipline->term_IO(cqr) == 0) {
+			list_del(&cqr->list);
+			finished = 1;
+		}
+		spin_unlock_irq(get_ccwdev_lock(device->cdev));
+	}
+	return rc;
+}
+
+/*
+ * 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, list);
+	rc = device->discipline->term_IO(cqr);
+	if (rc == 0) {
+		/* termination successful */
+		cqr->status = DASD_CQR_QUEUED;
+		cqr->startclk = cqr->stopclk = 0;
+		cqr->starttime = 0;
+	}
+	return rc;
+}
+
+int
+dasd_sleep_on_immediatly(struct dasd_ccw_req * cqr)
+{
+	wait_queue_head_t wait_q;
+	struct dasd_device *device;
+	int rc;
+	
+	device = cqr->device;
+	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;
+	}
+	
+	init_waitqueue_head (&wait_q);
+	cqr->callback = dasd_wakeup_cb;
+	cqr->callback_data = (void *) &wait_q;
+	cqr->status = DASD_CQR_QUEUED;
+	list_add(&cqr->list, &device->ccw_queue);
+	
+	/* let the bh start the request to keep them in order */
+	dasd_schedule_bh(device);
+	
+	spin_unlock_irq(get_ccwdev_lock(device->cdev));
+
+	wait_event(wait_q, _wait_for_wakeup(cqr));
+	
+	/* Request status is either done or failed. */
+	rc = (cqr->status == DASD_CQR_FAILED) ? -EIO : 0;
+	return rc;
+}
+
+/*
+ * 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 1 if the request has been terminated.
+ */
+int
+dasd_cancel_req(struct dasd_ccw_req *cqr)
+{
+	struct dasd_device *device = cqr->device;
+	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 failed */
+		cqr->status = DASD_CQR_FAILED;
+		break;
+	case DASD_CQR_IN_IO:
+		/* request in IO - terminate IO and release again */
+		if (device->discipline->term_IO(cqr) != 0)
+			/* what to do if unable to terminate ??????
+			   e.g. not _IN_IO */
+			cqr->status = DASD_CQR_FAILED;
+		cqr->stopclk = get_clock();
+		rc = 1;
+		break;
+	case DASD_CQR_DONE:
+	case DASD_CQR_FAILED:
+		/* already finished - do nothing */
+		break;
+	default:
+		DEV_MESSAGE(KERN_ALERT, device,
+			    "invalid status %02x in request",
+			    cqr->status);
+		BUG();
+
+	}
+	spin_unlock_irqrestore(get_ccwdev_lock(device->cdev), flags);
+	dasd_schedule_bh(device);
+	return rc;
+}
+
+/*
+ * SECTION: Block device operations (request queue, partitions, open, release).
+ */
+
+/*
+ * Dasd request queue function. Called from ll_rw_blk.c
+ */
+static void
+do_dasd_request(request_queue_t * queue)
+{
+	struct dasd_device *device;
+
+	device = (struct dasd_device *) queue->queuedata;
+	spin_lock(get_ccwdev_lock(device->cdev));
+	/* Get new request from the block device request queue */
+	__dasd_process_blk_queue(device);
+	/* Now check if the head of the ccw queue needs to be started. */
+	__dasd_start_head(device);
+	spin_unlock(get_ccwdev_lock(device->cdev));
+}
+
+/*
+ * Allocate and initialize request queue and default I/O scheduler.
+ */
+static int
+dasd_alloc_queue(struct dasd_device * device)
+{
+	int rc;
+
+	device->request_queue = blk_init_queue(do_dasd_request,
+					       &device->request_queue_lock);
+	if (device->request_queue == NULL)
+		return -ENOMEM;
+
+	device->request_queue->queuedata = device;
+
+	elevator_exit(device->request_queue->elevator);
+	rc = elevator_init(device->request_queue, "deadline");
+	if (rc) {
+		blk_cleanup_queue(device->request_queue);
+		return rc;
+	}
+	return 0;
+}
+
+/*
+ * Allocate and initialize request queue.
+ */
+static void
+dasd_setup_queue(struct dasd_device * device)
+{
+	int max;
+
+	blk_queue_hardsect_size(device->request_queue, device->bp_block);
+	max = device->discipline->max_blocks << device->s2b_shift;
+	blk_queue_max_sectors(device->request_queue, max);
+	blk_queue_max_phys_segments(device->request_queue, -1L);
+	blk_queue_max_hw_segments(device->request_queue, -1L);
+	blk_queue_max_segment_size(device->request_queue, -1L);
+	blk_queue_segment_boundary(device->request_queue, -1L);
+}
+
+/*
+ * Deactivate and free request queue.
+ */
+static void
+dasd_free_queue(struct dasd_device * device)
+{
+	if (device->request_queue) {
+		blk_cleanup_queue(device->request_queue);
+		device->request_queue = NULL;
+	}
+}
+
+/*
+ * Flush request on the request queue.
+ */
+static void
+dasd_flush_request_queue(struct dasd_device * device)
+{
+	struct request *req;
+
+	if (!device->request_queue)
+		return;
+	
+	spin_lock_irq(&device->request_queue_lock);
+	while (!list_empty(&device->request_queue->queue_head)) {
+		req = elv_next_request(device->request_queue);
+		if (req == NULL)
+			break;
+		dasd_end_request(req, 0);
+		blkdev_dequeue_request(req);
+	}
+	spin_unlock_irq(&device->request_queue_lock);
+}
+
+static int
+dasd_open(struct inode *inp, struct file *filp)
+{
+	struct gendisk *disk = inp->i_bdev->bd_disk;
+	struct dasd_device *device = disk->private_data;
+	int rc;
+
+        atomic_inc(&device->open_count);
+	if (test_bit(DASD_FLAG_OFFLINE, &device->flags)) {
+		rc = -ENODEV;
+		goto unlock;
+	}
+
+	if (!try_module_get(device->discipline->owner)) {
+		rc = -EINVAL;
+		goto unlock;
+	}
+
+	if (dasd_probeonly) {
+		DEV_MESSAGE(KERN_INFO, device, "%s",
+			    "No access to device due to probeonly mode");
+		rc = -EPERM;
+		goto out;
+	}
+
+	if (device->state < DASD_STATE_BASIC) {
+		DBF_DEV_EVENT(DBF_ERR, device, " %s",
+			      " Cannot open unrecognized device");
+		rc = -ENODEV;
+		goto out;
+	}
+
+	return 0;
+
+out:
+	module_put(device->discipline->owner);
+unlock:
+	atomic_dec(&device->open_count);
+	return rc;
+}
+
+static int
+dasd_release(struct inode *inp, struct file *filp)
+{
+	struct gendisk *disk = inp->i_bdev->bd_disk;
+	struct dasd_device *device = disk->private_data;
+
+	atomic_dec(&device->open_count);
+	module_put(device->discipline->owner);
+	return 0;
+}
+
+struct block_device_operations
+dasd_device_operations = {
+	.owner		= THIS_MODULE,
+	.open		= dasd_open,
+	.release	= dasd_release,
+	.ioctl		= dasd_ioctl,
+};
+
+
+static void
+dasd_exit(void)
+{
+#ifdef CONFIG_PROC_FS
+	dasd_proc_exit();
+#endif
+	dasd_ioctl_exit();
+	dasd_gendisk_exit();
+	dasd_devmap_exit();
+	devfs_remove("dasd");
+	if (dasd_debug_area != NULL) {
+		debug_unregister(dasd_debug_area);
+		dasd_debug_area = NULL;
+	}
+}
+
+/*
+ * SECTION: common functions for ccw_driver use
+ */
+
+/* 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) {
+		printk(KERN_WARNING
+		       "dasd_generic_probe: could not add sysfs entries "
+		       "for %s\n", cdev->dev.bus_id);
+	}
+
+	cdev->handler = &dasd_int_handler;
+
+	return ret;
+}
+
+/* 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;
+
+	dasd_remove_sysfs_files(cdev);
+	device = dasd_device_from_cdev(cdev);
+	if (IS_ERR(device))
+		return;
+	if (test_and_set_bit(DASD_FLAG_OFFLINE, &device->flags)) {
+		/* Already doing offline processing */
+		dasd_put_device(device);
+		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. */
+	dasd_delete_device(device);
+}
+
+/* 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 *discipline)
+
+{
+	struct dasd_device *device;
+	int rc;
+
+	device = dasd_create_device(cdev);
+	if (IS_ERR(device))
+		return PTR_ERR(device);
+
+	if (test_bit(DASD_FLAG_USE_DIAG, &device->flags)) {
+	  	if (!dasd_diag_discipline_pointer) {
+		        printk (KERN_WARNING
+				"dasd_generic couldn't online device %s "
+				"- discipline DIAG not available\n",
+				cdev->dev.bus_id);
+			dasd_delete_device(device);
+			return -ENODEV;
+		}
+		discipline = dasd_diag_discipline_pointer;
+	}
+	device->discipline = discipline;
+
+	rc = discipline->check_device(device);
+	if (rc) {
+		printk (KERN_WARNING
+			"dasd_generic couldn't online device %s "
+			"with discipline %s rc=%i\n",
+			cdev->dev.bus_id, discipline->name, rc);
+		dasd_delete_device(device);
+		return rc;
+	}
+
+	dasd_set_target_state(device, DASD_STATE_ONLINE);
+	if (device->state <= DASD_STATE_KNOWN) {
+		printk (KERN_WARNING
+			"dasd_generic discipline not found for %s\n",
+			cdev->dev.bus_id);
+		rc = -ENODEV;
+		dasd_set_target_state(device, DASD_STATE_NEW);
+		dasd_delete_device(device);
+	} else
+		pr_debug("dasd_generic device %s found\n",
+				cdev->dev.bus_id);
+
+	/* FIXME: we have to wait for the root device but we don't want
+	 * to wait for each single device but for all at once. */
+	wait_event(dasd_init_waitq, _wait_for_device(device));
+
+	dasd_put_device(device);
+
+	return rc;
+}
+
+int
+dasd_generic_set_offline (struct ccw_device *cdev)
+{
+	struct dasd_device *device;
+	int max_count;
+
+	device = dasd_device_from_cdev(cdev);
+	if (IS_ERR(device))
+		return PTR_ERR(device);
+	if (test_and_set_bit(DASD_FLAG_OFFLINE, &device->flags)) {
+		/* Already doing offline processing */
+		dasd_put_device(device);
+		return 0;
+	}
+	/*
+	 * 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.
+	 */
+	max_count = device->bdev ? 0 : -1;
+	if (atomic_read(&device->open_count) > max_count) {
+		printk (KERN_WARNING "Can't offline dasd device with open"
+			" count = %i.\n",
+			atomic_read(&device->open_count));
+		clear_bit(DASD_FLAG_OFFLINE, &device->flags);
+		dasd_put_device(device);
+		return -EBUSY;
+	}
+	dasd_set_target_state(device, DASD_STATE_NEW);
+	/* dasd_delete_device destroys the device reference. */
+	dasd_delete_device(device);
+
+	return 0;
+}
+
+int
+dasd_generic_notify(struct ccw_device *cdev, int event)
+{
+	struct dasd_device *device;
+	struct dasd_ccw_req *cqr;
+	unsigned long flags;
+	int ret;
+
+	device = dasd_device_from_cdev(cdev);
+	if (IS_ERR(device))
+		return 0;
+	spin_lock_irqsave(get_ccwdev_lock(cdev), flags);
+	ret = 0;
+	switch (event) {
+	case CIO_GONE:
+	case CIO_NO_PATH:
+		if (device->state < DASD_STATE_BASIC)
+			break;
+		/* Device is active. We want to keep it. */
+		if (test_bit(DASD_FLAG_DSC_ERROR, &device->flags)) {
+			list_for_each_entry(cqr, &device->ccw_queue, list)
+				if (cqr->status == DASD_CQR_IN_IO)
+					cqr->status = DASD_CQR_FAILED;
+			device->stopped |= DASD_STOPPED_DC_EIO;
+			dasd_schedule_bh(device);
+		} else {
+			list_for_each_entry(cqr, &device->ccw_queue, list)
+				if (cqr->status == DASD_CQR_IN_IO) {
+					cqr->status = DASD_CQR_QUEUED;
+					cqr->retries++;
+				}
+			device->stopped |= DASD_STOPPED_DC_WAIT;
+			dasd_set_timer(device, 0);
+		}
+		ret = 1;
+		break;
+	case CIO_OPER:
+		/* FIXME: add a sanity check. */
+		device->stopped &= ~(DASD_STOPPED_DC_WAIT|DASD_STOPPED_DC_EIO);
+		dasd_schedule_bh(device);
+		ret = 1;
+		break;
+	}
+	spin_unlock_irqrestore(get_ccwdev_lock(cdev), flags);
+	dasd_put_device(device);
+	return ret;
+}
+
+/*
+ * Automatically online either all dasd devices (dasd_autodetect) or
+ * all devices specified with dasd= parameters.
+ */
+void
+dasd_generic_auto_online (struct ccw_driver *dasd_discipline_driver)
+{
+	struct device_driver *drv;
+	struct device *d, *dev;
+	struct ccw_device *cdev;
+
+	drv = get_driver(&dasd_discipline_driver->driver);
+	down_read(&drv->bus->subsys.rwsem);
+	dev = NULL;
+	list_for_each_entry(d, &drv->devices, driver_list) {
+		dev = get_device(d);
+		if (!dev)
+			continue;
+		cdev = to_ccwdev(dev);
+		if (dasd_autodetect || dasd_busid_known(cdev->dev.bus_id) == 0)
+			ccw_device_set_online(cdev);
+		put_device(dev);
+	}
+	up_read(&drv->bus->subsys.rwsem);
+	put_driver(drv);
+}
+
+static int __init
+dasd_init(void)
+{
+	int rc;
+
+	init_waitqueue_head(&dasd_init_waitq);
+
+	/* register 'common' DASD debug area, used for all DBF_XXX calls */
+	dasd_debug_area = debug_register("dasd", 0, 2, 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_EMERG);
+
+	DBF_EVENT(DBF_EMERG, "%s", "debug area created");
+
+	dasd_diag_discipline_pointer = NULL;
+
+	rc = devfs_mk_dir("dasd");
+	if (rc)
+		goto failed;
+	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_ioctl_init();
+	if (rc)
+		goto failed;
+#ifdef CONFIG_PROC_FS
+	rc = dasd_proc_init();
+	if (rc)
+		goto failed;
+#endif
+
+	return 0;
+failed:
+	MESSAGE(KERN_INFO, "%s", "initialization not performed due to errors");
+	dasd_exit();
+	return rc;
+}
+
+module_init(dasd_init);
+module_exit(dasd_exit);
+
+EXPORT_SYMBOL(dasd_debug_area);
+EXPORT_SYMBOL(dasd_diag_discipline_pointer);
+
+EXPORT_SYMBOL(dasd_add_request_head);
+EXPORT_SYMBOL(dasd_add_request_tail);
+EXPORT_SYMBOL(dasd_cancel_req);
+EXPORT_SYMBOL(dasd_clear_timer);
+EXPORT_SYMBOL(dasd_enable_device);
+EXPORT_SYMBOL(dasd_int_handler);
+EXPORT_SYMBOL(dasd_kfree_request);
+EXPORT_SYMBOL(dasd_kick_device);
+EXPORT_SYMBOL(dasd_kmalloc_request);
+EXPORT_SYMBOL(dasd_schedule_bh);
+EXPORT_SYMBOL(dasd_set_target_state);
+EXPORT_SYMBOL(dasd_set_timer);
+EXPORT_SYMBOL(dasd_sfree_request);
+EXPORT_SYMBOL(dasd_sleep_on);
+EXPORT_SYMBOL(dasd_sleep_on_immediatly);
+EXPORT_SYMBOL(dasd_sleep_on_interruptible);
+EXPORT_SYMBOL(dasd_smalloc_request);
+EXPORT_SYMBOL(dasd_start_IO);
+EXPORT_SYMBOL(dasd_term_IO);
+
+EXPORT_SYMBOL_GPL(dasd_generic_probe);
+EXPORT_SYMBOL_GPL(dasd_generic_remove);
+EXPORT_SYMBOL_GPL(dasd_generic_notify);
+EXPORT_SYMBOL_GPL(dasd_generic_set_online);
+EXPORT_SYMBOL_GPL(dasd_generic_set_offline);
+EXPORT_SYMBOL_GPL(dasd_generic_auto_online);
+
+/*
+ * Overrides for Emacs so that we follow Linus's tabbing style.
+ * Emacs will notice this stuff at the end of the file and automatically
+ * adjust the settings for this buffer only.  This must remain at the end
+ * of the file.
+ * ---------------------------------------------------------------------------
+ * Local variables:
+ * c-indent-level: 4
+ * c-brace-imaginary-offset: 0
+ * c-brace-offset: -4
+ * c-argdecl-indent: 4
+ * c-label-offset: -4
+ * c-continued-statement-offset: 4
+ * c-continued-brace-offset: 0
+ * indent-tabs-mode: 1
+ * tab-width: 8
+ * End:
+ */