Linux-2.6.12-rc2v2.6.12-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, 775 insertions, 0 deletions

diff --git a/drivers/s390/block/dcssblk.c b/drivers/s390/block/dcssblk.c
new file mode 100644
index 00000000000..a66b17b6529
--- /dev/null
+++ b/drivers/s390/block/dcssblk.c
@@ -0,0 +1,775 @@
+/*
+ * dcssblk.c -- the S/390 block driver for dcss memory
+ *
+ * Authors: Carsten Otte, Stefan Weinhuber, Gerald Schaefer
+ */
+
+#include <linux/module.h>
+#include <linux/moduleparam.h>
+#include <linux/ctype.h>
+#include <linux/errno.h>
+#include <linux/init.h>
+#include <linux/slab.h>
+#include <linux/blkdev.h>
+#include <asm/extmem.h>
+#include <asm/io.h>
+#include <linux/completion.h>
+#include <linux/interrupt.h>
+#include <asm/ccwdev.h> 	// for s390_root_dev_(un)register()
+
+//#define DCSSBLK_DEBUG		/* Debug messages on/off */
+#define DCSSBLK_NAME "dcssblk"
+#define DCSSBLK_MINORS_PER_DISK 1
+#define DCSSBLK_PARM_LEN 400
+
+#ifdef DCSSBLK_DEBUG
+#define PRINT_DEBUG(x...) printk(KERN_DEBUG DCSSBLK_NAME " debug: " x)
+#else
+#define PRINT_DEBUG(x...) do {} while (0)
+#endif
+#define PRINT_INFO(x...)  printk(KERN_INFO DCSSBLK_NAME " info: " x)
+#define PRINT_WARN(x...)  printk(KERN_WARNING DCSSBLK_NAME " warning: " x)
+#define PRINT_ERR(x...)	  printk(KERN_ERR DCSSBLK_NAME " error: " x)
+
+
+static int dcssblk_open(struct inode *inode, struct file *filp);
+static int dcssblk_release(struct inode *inode, struct file *filp);
+static int dcssblk_make_request(struct request_queue *q, struct bio *bio);
+
+static char dcssblk_segments[DCSSBLK_PARM_LEN] = "\0";
+
+static int dcssblk_major;
+static struct block_device_operations dcssblk_devops = {
+	.owner   = THIS_MODULE,
+	.open    = dcssblk_open,
+	.release = dcssblk_release,
+};
+
+static ssize_t dcssblk_add_store(struct device * dev, const char * buf,
+				  size_t count);
+static ssize_t dcssblk_remove_store(struct device * dev, const char * buf,
+				  size_t count);
+static ssize_t dcssblk_save_store(struct device * dev, const char * buf,
+				  size_t count);
+static ssize_t dcssblk_save_show(struct device *dev, char *buf);
+static ssize_t dcssblk_shared_store(struct device * dev, const char * buf,
+				  size_t count);
+static ssize_t dcssblk_shared_show(struct device *dev, char *buf);
+
+static DEVICE_ATTR(add, S_IWUSR, NULL, dcssblk_add_store);
+static DEVICE_ATTR(remove, S_IWUSR, NULL, dcssblk_remove_store);
+static DEVICE_ATTR(save, S_IWUSR | S_IRUGO, dcssblk_save_show,
+		   dcssblk_save_store);
+static DEVICE_ATTR(shared, S_IWUSR | S_IRUGO, dcssblk_shared_show,
+		   dcssblk_shared_store);
+
+static struct device *dcssblk_root_dev;
+
+struct dcssblk_dev_info {
+	struct list_head lh;
+	struct device dev;
+	char segment_name[BUS_ID_SIZE];
+	atomic_t use_count;
+	struct gendisk *gd;
+	unsigned long start;
+	unsigned long end;
+	int segment_type;
+	unsigned char save_pending;
+	unsigned char is_shared;
+	struct request_queue *dcssblk_queue;
+};
+
+static struct list_head dcssblk_devices = LIST_HEAD_INIT(dcssblk_devices);
+static struct rw_semaphore dcssblk_devices_sem;
+
+/*
+ * release function for segment device.
+ */
+static void
+dcssblk_release_segment(struct device *dev)
+{
+	PRINT_DEBUG("segment release fn called for %s\n", dev->bus_id);
+	kfree(container_of(dev, struct dcssblk_dev_info, dev));
+	module_put(THIS_MODULE);
+}
+
+/*
+ * get a minor number. needs to be called with
+ * down_write(&dcssblk_devices_sem) and the
+ * device needs to be enqueued before the semaphore is
+ * freed.
+ */
+static inline int
+dcssblk_assign_free_minor(struct dcssblk_dev_info *dev_info)
+{
+	int minor, found;
+	struct dcssblk_dev_info *entry;
+
+	if (dev_info == NULL)
+		return -EINVAL;
+	for (minor = 0; minor < (1<<MINORBITS); minor++) {
+		found = 0;
+		// test if minor available
+		list_for_each_entry(entry, &dcssblk_devices, lh)
+			if (minor == entry->gd->first_minor)
+				found++;
+		if (!found) break; // got unused minor
+	}
+	if (found)
+		return -EBUSY;
+	dev_info->gd->first_minor = minor;
+	return 0;
+}
+
+/*
+ * get the struct dcssblk_dev_info from dcssblk_devices
+ * for the given name.
+ * down_read(&dcssblk_devices_sem) must be held.
+ */
+static struct dcssblk_dev_info *
+dcssblk_get_device_by_name(char *name)
+{
+	struct dcssblk_dev_info *entry;
+
+	list_for_each_entry(entry, &dcssblk_devices, lh) {
+		if (!strcmp(name, entry->segment_name)) {
+			return entry;
+		}
+	}
+	return NULL;
+}
+
+/*
+ * print appropriate error message for segment_load()/segment_type()
+ * return code
+ */
+static void
+dcssblk_segment_warn(int rc, char* seg_name)
+{
+	switch (rc) {
+	case -ENOENT:
+		PRINT_WARN("cannot load/query segment %s, does not exist\n",
+			   seg_name);
+		break;
+	case -ENOSYS:
+		PRINT_WARN("cannot load/query segment %s, not running on VM\n",
+			   seg_name);
+		break;
+	case -EIO:
+		PRINT_WARN("cannot load/query segment %s, hardware error\n",
+			   seg_name);
+		break;
+	case -ENOTSUPP:
+		PRINT_WARN("cannot load/query segment %s, is a multi-part "
+			   "segment\n", seg_name);
+		break;
+	case -ENOSPC:
+		PRINT_WARN("cannot load/query segment %s, overlaps with "
+			   "storage\n", seg_name);
+		break;
+	case -EBUSY:
+		PRINT_WARN("cannot load/query segment %s, overlaps with "
+			   "already loaded dcss\n", seg_name);
+		break;
+	case -EPERM:
+		PRINT_WARN("cannot load/query segment %s, already loaded in "
+			   "incompatible mode\n", seg_name);
+		break;
+	case -ENOMEM:
+		PRINT_WARN("cannot load/query segment %s, out of memory\n",
+			   seg_name);
+		break;
+	case -ERANGE:
+		PRINT_WARN("cannot load/query segment %s, exceeds kernel "
+			   "mapping range\n", seg_name);
+		break;
+	default:
+		PRINT_WARN("cannot load/query segment %s, return value %i\n",
+			   seg_name, rc);
+		break;
+	}
+}
+
+/*
+ * device attribute for switching shared/nonshared (exclusive)
+ * operation (show + store)
+ */
+static ssize_t
+dcssblk_shared_show(struct device *dev, char *buf)
+{
+	struct dcssblk_dev_info *dev_info;
+
+	dev_info = container_of(dev, struct dcssblk_dev_info, dev);
+	return sprintf(buf, dev_info->is_shared ? "1\n" : "0\n");
+}
+
+static ssize_t
+dcssblk_shared_store(struct device *dev, const char *inbuf, size_t count)
+{
+	struct dcssblk_dev_info *dev_info;
+	int rc;
+
+	if ((count > 1) && (inbuf[1] != '\n') && (inbuf[1] != '\0')) {
+		PRINT_WARN("Invalid value, must be 0 or 1\n");
+		return -EINVAL;
+	}
+	down_write(&dcssblk_devices_sem);
+	dev_info = container_of(dev, struct dcssblk_dev_info, dev);
+	if (atomic_read(&dev_info->use_count)) {
+		PRINT_ERR("share: segment %s is busy!\n",
+			  dev_info->segment_name);
+		rc = -EBUSY;
+		goto out;
+	}
+	if (inbuf[0] == '1') {
+		// reload segment in shared mode
+		rc = segment_modify_shared(dev_info->segment_name,
+					   SEGMENT_SHARED);
+		if (rc < 0) {
+			BUG_ON(rc == -EINVAL);
+			if (rc == -EIO || rc == -ENOENT)
+				goto removeseg;
+		} else {
+			dev_info->is_shared = 1;
+			switch (dev_info->segment_type) {
+				case SEG_TYPE_SR:
+				case SEG_TYPE_ER:
+				case SEG_TYPE_SC:
+					set_disk_ro(dev_info->gd,1);
+			}
+		}
+	} else if (inbuf[0] == '0') {
+		// reload segment in exclusive mode
+		if (dev_info->segment_type == SEG_TYPE_SC) {
+			PRINT_ERR("Segment type SC (%s) cannot be loaded in "
+				  "non-shared mode\n", dev_info->segment_name);
+			rc = -EINVAL;
+			goto out;
+		}
+		rc = segment_modify_shared(dev_info->segment_name,
+					   SEGMENT_EXCLUSIVE);
+		if (rc < 0) {
+			BUG_ON(rc == -EINVAL);
+			if (rc == -EIO || rc == -ENOENT)
+				goto removeseg;
+		} else {
+			dev_info->is_shared = 0;
+			set_disk_ro(dev_info->gd, 0);
+		}
+	} else {
+		PRINT_WARN("Invalid value, must be 0 or 1\n");
+		rc = -EINVAL;
+		goto out;
+	}
+	rc = count;
+	goto out;
+
+removeseg:
+	PRINT_ERR("Could not reload segment %s, removing it now!\n",
+			dev_info->segment_name);
+	list_del(&dev_info->lh);
+
+	del_gendisk(dev_info->gd);
+	blk_put_queue(dev_info->dcssblk_queue);
+	dev_info->gd->queue = NULL;
+	put_disk(dev_info->gd);
+	device_unregister(dev);
+	put_device(dev);
+out:
+	up_write(&dcssblk_devices_sem);
+	return rc;
+}
+
+/*
+ * device attribute for save operation on current copy
+ * of the segment. If the segment is busy, saving will
+ * become pending until it gets released, which can be
+ * undone by storing a non-true value to this entry.
+ * (show + store)
+ */
+static ssize_t
+dcssblk_save_show(struct device *dev, char *buf)
+{
+	struct dcssblk_dev_info *dev_info;
+
+	dev_info = container_of(dev, struct dcssblk_dev_info, dev);
+	return sprintf(buf, dev_info->save_pending ? "1\n" : "0\n");
+}
+
+static ssize_t
+dcssblk_save_store(struct device *dev, const char *inbuf, size_t count)
+{
+	struct dcssblk_dev_info *dev_info;
+
+	if ((count > 1) && (inbuf[1] != '\n') && (inbuf[1] != '\0')) {
+		PRINT_WARN("Invalid value, must be 0 or 1\n");
+		return -EINVAL;
+	}
+	dev_info = container_of(dev, struct dcssblk_dev_info, dev);
+
+	down_write(&dcssblk_devices_sem);
+	if (inbuf[0] == '1') {
+		if (atomic_read(&dev_info->use_count) == 0) {
+			// device is idle => we save immediately
+			PRINT_INFO("Saving segment %s\n",
+				   dev_info->segment_name);
+			segment_save(dev_info->segment_name);
+		}  else {
+			// device is busy => we save it when it becomes
+			// idle in dcssblk_release
+			PRINT_INFO("Segment %s is currently busy, it will "
+				   "be saved when it becomes idle...\n",
+				   dev_info->segment_name);
+			dev_info->save_pending = 1;
+		}
+	} else if (inbuf[0] == '0') {
+		if (dev_info->save_pending) {
+			// device is busy & the user wants to undo his save
+			// request
+			dev_info->save_pending = 0;
+			PRINT_INFO("Pending save for segment %s deactivated\n",
+					dev_info->segment_name);
+		}
+	} else {
+		up_write(&dcssblk_devices_sem);
+		PRINT_WARN("Invalid value, must be 0 or 1\n");
+		return -EINVAL;
+	}
+	up_write(&dcssblk_devices_sem);
+	return count;
+}
+
+/*
+ * device attribute for adding devices
+ */
+static ssize_t
+dcssblk_add_store(struct device *dev, const char *buf, size_t count)
+{
+	int rc, i;
+	struct dcssblk_dev_info *dev_info;
+	char *local_buf;
+	unsigned long seg_byte_size;
+
+	dev_info = NULL;
+	if (dev != dcssblk_root_dev) {
+		rc = -EINVAL;
+		goto out_nobuf;
+	}
+	local_buf = kmalloc(count + 1, GFP_KERNEL);
+	if (local_buf == NULL) {
+		rc = -ENOMEM;
+		goto out_nobuf;
+	}
+	/*
+	 * parse input
+	 */
+	for (i = 0; ((buf[i] != '\0') && (buf[i] != '\n') && i < count); i++) {
+		local_buf[i] = toupper(buf[i]);
+	}
+	local_buf[i] = '\0';
+	if ((i == 0) || (i > 8)) {
+		rc = -ENAMETOOLONG;
+		goto out;
+	}
+	/*
+	 * already loaded?
+	 */
+	down_read(&dcssblk_devices_sem);
+	dev_info = dcssblk_get_device_by_name(local_buf);
+	up_read(&dcssblk_devices_sem);
+	if (dev_info != NULL) {
+		PRINT_WARN("Segment %s already loaded!\n", local_buf);
+		rc = -EEXIST;
+		goto out;
+	}
+	/*
+	 * get a struct dcssblk_dev_info
+	 */
+	dev_info = kmalloc(sizeof(struct dcssblk_dev_info), GFP_KERNEL);
+	if (dev_info == NULL) {
+		rc = -ENOMEM;
+		goto out;
+	}
+	memset(dev_info, 0, sizeof(struct dcssblk_dev_info));
+
+	strcpy(dev_info->segment_name, local_buf);
+	strlcpy(dev_info->dev.bus_id, local_buf, BUS_ID_SIZE);
+	dev_info->dev.release = dcssblk_release_segment;
+	INIT_LIST_HEAD(&dev_info->lh);
+
+	dev_info->gd = alloc_disk(DCSSBLK_MINORS_PER_DISK);
+	if (dev_info->gd == NULL) {
+		rc = -ENOMEM;
+		goto free_dev_info;
+	}
+	dev_info->gd->major = dcssblk_major;
+	dev_info->gd->fops = &dcssblk_devops;
+	dev_info->dcssblk_queue = blk_alloc_queue(GFP_KERNEL);
+	dev_info->gd->queue = dev_info->dcssblk_queue;
+	dev_info->gd->private_data = dev_info;
+	dev_info->gd->driverfs_dev = &dev_info->dev;
+	/*
+	 * load the segment
+	 */
+	rc = segment_load(local_buf, SEGMENT_SHARED,
+				&dev_info->start, &dev_info->end);
+	if (rc < 0) {
+		dcssblk_segment_warn(rc, dev_info->segment_name);
+		goto dealloc_gendisk;
+	}
+	seg_byte_size = (dev_info->end - dev_info->start + 1);
+	set_capacity(dev_info->gd, seg_byte_size >> 9); // size in sectors
+	PRINT_INFO("Loaded segment %s, size = %lu Byte, "
+		   "capacity = %lu (512 Byte) sectors\n", local_buf,
+		   seg_byte_size, seg_byte_size >> 9);
+
+	dev_info->segment_type = rc;
+	dev_info->save_pending = 0;
+	dev_info->is_shared = 1;
+	dev_info->dev.parent = dcssblk_root_dev;
+
+	/*
+	 * get minor, add to list
+	 */
+	down_write(&dcssblk_devices_sem);
+	rc = dcssblk_assign_free_minor(dev_info);
+	if (rc) {
+		up_write(&dcssblk_devices_sem);
+		PRINT_ERR("No free minor number available! "
+			  "Unloading segment...\n");
+		goto unload_seg;
+	}
+	sprintf(dev_info->gd->disk_name, "dcssblk%d",
+		dev_info->gd->first_minor);
+	list_add_tail(&dev_info->lh, &dcssblk_devices);
+
+	if (!try_module_get(THIS_MODULE)) {
+		rc = -ENODEV;
+		goto list_del;
+	}
+	/*
+	 * register the device
+	 */
+	rc = device_register(&dev_info->dev);
+	if (rc) {
+		PRINT_ERR("Segment %s could not be registered RC=%d\n",
+				local_buf, rc);
+		module_put(THIS_MODULE);
+		goto list_del;
+	}
+	get_device(&dev_info->dev);
+	rc = device_create_file(&dev_info->dev, &dev_attr_shared);
+	if (rc)
+		goto unregister_dev;
+	rc = device_create_file(&dev_info->dev, &dev_attr_save);
+	if (rc)
+		goto unregister_dev;
+
+	add_disk(dev_info->gd);
+
+	blk_queue_make_request(dev_info->dcssblk_queue, dcssblk_make_request);
+	blk_queue_hardsect_size(dev_info->dcssblk_queue, 4096);
+
+	switch (dev_info->segment_type) {
+		case SEG_TYPE_SR:
+		case SEG_TYPE_ER:
+		case SEG_TYPE_SC:
+			set_disk_ro(dev_info->gd,1);
+			break;
+		default:
+			set_disk_ro(dev_info->gd,0);
+			break;
+	}
+	PRINT_DEBUG("Segment %s loaded successfully\n", local_buf);
+	up_write(&dcssblk_devices_sem);
+	rc = count;
+	goto out;
+
+unregister_dev:
+	PRINT_ERR("device_create_file() failed!\n");
+	list_del(&dev_info->lh);
+	blk_put_queue(dev_info->dcssblk_queue);
+	dev_info->gd->queue = NULL;
+	put_disk(dev_info->gd);
+	device_unregister(&dev_info->dev);
+	segment_unload(dev_info->segment_name);
+	put_device(&dev_info->dev);
+	up_write(&dcssblk_devices_sem);
+	goto out;
+list_del:
+	list_del(&dev_info->lh);
+	up_write(&dcssblk_devices_sem);
+unload_seg:
+	segment_unload(local_buf);
+dealloc_gendisk:
+	blk_put_queue(dev_info->dcssblk_queue);
+	dev_info->gd->queue = NULL;
+	put_disk(dev_info->gd);
+free_dev_info:
+	kfree(dev_info);
+out:
+	kfree(local_buf);
+out_nobuf:
+	return rc;
+}
+
+/*
+ * device attribute for removing devices
+ */
+static ssize_t
+dcssblk_remove_store(struct device *dev, const char *buf, size_t count)
+{
+	struct dcssblk_dev_info *dev_info;
+	int rc, i;
+	char *local_buf;
+
+	if (dev != dcssblk_root_dev) {
+		return -EINVAL;
+	}
+	local_buf = kmalloc(count + 1, GFP_KERNEL);
+	if (local_buf == NULL) {
+		return -ENOMEM;
+	}
+	/*
+	 * parse input
+	 */
+	for (i = 0; ((*(buf+i)!='\0') && (*(buf+i)!='\n') && i < count); i++) {
+		local_buf[i] = toupper(buf[i]);
+	}
+	local_buf[i] = '\0';
+	if ((i == 0) || (i > 8)) {
+		rc = -ENAMETOOLONG;
+		goto out_buf;
+	}
+
+	down_write(&dcssblk_devices_sem);
+	dev_info = dcssblk_get_device_by_name(local_buf);
+	if (dev_info == NULL) {
+		up_write(&dcssblk_devices_sem);
+		PRINT_WARN("Segment %s is not loaded!\n", local_buf);
+		rc = -ENODEV;
+		goto out_buf;
+	}
+	if (atomic_read(&dev_info->use_count) != 0) {
+		up_write(&dcssblk_devices_sem);
+		PRINT_WARN("Segment %s is in use!\n", local_buf);
+		rc = -EBUSY;
+		goto out_buf;
+	}
+	list_del(&dev_info->lh);
+
+	del_gendisk(dev_info->gd);
+	blk_put_queue(dev_info->dcssblk_queue);
+	dev_info->gd->queue = NULL;
+	put_disk(dev_info->gd);
+	device_unregister(&dev_info->dev);
+	segment_unload(dev_info->segment_name);
+	PRINT_DEBUG("Segment %s unloaded successfully\n",
+			dev_info->segment_name);
+	put_device(&dev_info->dev);
+	up_write(&dcssblk_devices_sem);
+
+	rc = count;
+out_buf:
+	kfree(local_buf);
+	return rc;
+}
+
+static int
+dcssblk_open(struct inode *inode, struct file *filp)
+{
+	struct dcssblk_dev_info *dev_info;
+	int rc;
+
+	dev_info = inode->i_bdev->bd_disk->private_data;
+	if (NULL == dev_info) {
+		rc = -ENODEV;
+		goto out;
+	}
+	atomic_inc(&dev_info->use_count);
+	inode->i_bdev->bd_block_size = 4096;
+	rc = 0;
+out:
+	return rc;
+}
+
+static int
+dcssblk_release(struct inode *inode, struct file *filp)
+{
+	struct dcssblk_dev_info *dev_info;
+	int rc;
+
+	dev_info = inode->i_bdev->bd_disk->private_data;
+	if (NULL == dev_info) {
+		rc = -ENODEV;
+		goto out;
+	}
+	down_write(&dcssblk_devices_sem);
+	if (atomic_dec_and_test(&dev_info->use_count)
+	    && (dev_info->save_pending)) {
+		PRINT_INFO("Segment %s became idle and is being saved now\n",
+			    dev_info->segment_name);
+		segment_save(dev_info->segment_name);
+		dev_info->save_pending = 0;
+	}
+	up_write(&dcssblk_devices_sem);
+	rc = 0;
+out:
+	return rc;
+}
+
+static int
+dcssblk_make_request(request_queue_t *q, struct bio *bio)
+{
+	struct dcssblk_dev_info *dev_info;
+	struct bio_vec *bvec;
+	unsigned long index;
+	unsigned long page_addr;
+	unsigned long source_addr;
+	unsigned long bytes_done;
+	int i;
+
+	bytes_done = 0;
+	dev_info = bio->bi_bdev->bd_disk->private_data;
+	if (dev_info == NULL)
+		goto fail;
+	if ((bio->bi_sector & 7) != 0 || (bio->bi_size & 4095) != 0)
+		/* Request is not page-aligned. */
+		goto fail;
+	if (((bio->bi_size >> 9) + bio->bi_sector)
+			> get_capacity(bio->bi_bdev->bd_disk)) {
+		/* Request beyond end of DCSS segment. */
+		goto fail;
+	}
+	index = (bio->bi_sector >> 3);
+	bio_for_each_segment(bvec, bio, i) {
+		page_addr = (unsigned long)
+			page_address(bvec->bv_page) + bvec->bv_offset;
+		source_addr = dev_info->start + (index<<12) + bytes_done;
+		if (unlikely(page_addr & 4095) != 0 || (bvec->bv_len & 4095) != 0)
+			// More paranoia.
+			goto fail;
+		if (bio_data_dir(bio) == READ) {
+			memcpy((void*)page_addr, (void*)source_addr,
+				bvec->bv_len);
+		} else {
+			memcpy((void*)source_addr, (void*)page_addr,
+				bvec->bv_len);
+		}
+		bytes_done += bvec->bv_len;
+	}
+	bio_endio(bio, bytes_done, 0);
+	return 0;
+fail:
+	bio_io_error(bio, bytes_done);
+	return 0;
+}
+
+static void
+dcssblk_check_params(void)
+{
+	int rc, i, j, k;
+	char buf[9];
+	struct dcssblk_dev_info *dev_info;
+
+	for (i = 0; (i < DCSSBLK_PARM_LEN) && (dcssblk_segments[i] != '\0');
+	     i++) {
+		for (j = i; (dcssblk_segments[j] != ',')  &&
+			    (dcssblk_segments[j] != '\0') &&
+			    (dcssblk_segments[j] != '(')  &&
+			    (j - i) < 8; j++)
+		{
+			buf[j-i] = dcssblk_segments[j];
+		}
+		buf[j-i] = '\0';
+		rc = dcssblk_add_store(dcssblk_root_dev, buf, j-i);
+		if ((rc >= 0) && (dcssblk_segments[j] == '(')) {
+			for (k = 0; buf[k] != '\0'; k++)
+				buf[k] = toupper(buf[k]);
+			if (!strncmp(&dcssblk_segments[j], "(local)", 7)) {
+				down_read(&dcssblk_devices_sem);
+				dev_info = dcssblk_get_device_by_name(buf);
+				up_read(&dcssblk_devices_sem);
+				if (dev_info)
+					dcssblk_shared_store(&dev_info->dev,
+							     "0\n", 2);
+			}
+		}
+		while ((dcssblk_segments[j] != ',') &&
+		       (dcssblk_segments[j] != '\0'))
+		{
+			j++;
+		}
+		if (dcssblk_segments[j] == '\0')
+			break;
+		i = j;
+	}
+}
+
+/*
+ * The init/exit functions.
+ */
+static void __exit
+dcssblk_exit(void)
+{
+	int rc;
+
+	PRINT_DEBUG("DCSSBLOCK EXIT...\n");
+	s390_root_dev_unregister(dcssblk_root_dev);
+	rc = unregister_blkdev(dcssblk_major, DCSSBLK_NAME);
+	if (rc) {
+		PRINT_ERR("unregister_blkdev() failed!\n");
+	}
+	PRINT_DEBUG("...finished!\n");
+}
+
+static int __init
+dcssblk_init(void)
+{
+	int rc;
+
+	PRINT_DEBUG("DCSSBLOCK INIT...\n");
+	dcssblk_root_dev = s390_root_dev_register("dcssblk");
+	if (IS_ERR(dcssblk_root_dev)) {
+		PRINT_ERR("device_register() failed!\n");
+		return PTR_ERR(dcssblk_root_dev);
+	}
+	rc = device_create_file(dcssblk_root_dev, &dev_attr_add);
+	if (rc) {
+		PRINT_ERR("device_create_file(add) failed!\n");
+		s390_root_dev_unregister(dcssblk_root_dev);
+		return rc;
+	}
+	rc = device_create_file(dcssblk_root_dev, &dev_attr_remove);
+	if (rc) {
+		PRINT_ERR("device_create_file(remove) failed!\n");
+		s390_root_dev_unregister(dcssblk_root_dev);
+		return rc;
+	}
+	rc = register_blkdev(0, DCSSBLK_NAME);
+	if (rc < 0) {
+		PRINT_ERR("Can't get dynamic major!\n");
+		s390_root_dev_unregister(dcssblk_root_dev);
+		return rc;
+	}
+	dcssblk_major = rc;
+	init_rwsem(&dcssblk_devices_sem);
+
+	dcssblk_check_params();
+
+	PRINT_DEBUG("...finished!\n");
+	return 0;
+}
+
+module_init(dcssblk_init);
+module_exit(dcssblk_exit);
+
+module_param_string(segments, dcssblk_segments, DCSSBLK_PARM_LEN, 0444);
+MODULE_PARM_DESC(segments, "Name of DCSS segment(s) to be loaded, "
+		 "comma-separated list, each name max. 8 chars.\n"
+		 "Adding \"(local)\" to segment name equals echoing 0 to "
+		 "/sys/devices/dcssblk/<segment name>/shared after loading "
+		 "the segment - \n"
+		 "e.g. segments=\"mydcss1,mydcss2,mydcss3(local)\"");
+
+MODULE_LICENSE("GPL");