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, 920 insertions, 0 deletions

diff --git a/drivers/s390/char/vmlogrdr.c b/drivers/s390/char/vmlogrdr.c
new file mode 100644
index 000000000000..edf50d2bd10b
--- /dev/null
+++ b/drivers/s390/char/vmlogrdr.c
@@ -0,0 +1,920 @@
+/*
+ * drivers/s390/char/vmlogrdr.c
+ *      character device driver for reading z/VM system service records
+ *
+ *
+ *      Copyright (C) 2004 IBM Corporation
+ *      character device driver for reading z/VM system service records,
+ *      Version 1.0
+ *      Author(s): Xenia Tkatschow <xenia@us.ibm.com>
+ *                 Stefan Weinhuber <wein@de.ibm.com>
+ *
+ */
+#include <linux/module.h>
+#include <linux/init.h>
+#include <linux/errno.h>
+#include <linux/types.h>
+#include <linux/interrupt.h>
+#include <linux/spinlock.h>
+#include <asm/atomic.h>
+#include <asm/uaccess.h>
+#include <asm/cpcmd.h>
+#include <asm/debug.h>
+#include <asm/ebcdic.h>
+#include "../net/iucv.h"
+#include <linux/kmod.h>
+#include <linux/cdev.h>
+#include <linux/device.h>
+#include <linux/string.h>
+
+
+
+MODULE_AUTHOR
+        ("(C) 2004 IBM Corporation by Xenia Tkatschow (xenia@us.ibm.com)\n"
+         "                            Stefan Weinhuber (wein@de.ibm.com)");
+MODULE_DESCRIPTION ("Character device driver for reading z/VM "
+                    "system service records.");
+MODULE_LICENSE("GPL");
+
+
+/*
+ * The size of the buffer for iucv data transfer is one page,
+ * but in addition to the data we read from iucv we also
+ * place an integer and some characters into that buffer,
+ * so the maximum size for record data is a little less then
+ * one page.
+ */
+#define NET_BUFFER_SIZE (PAGE_SIZE - sizeof(int) - sizeof(FENCE))
+
+/*
+ * The elements that are concurrently accessed by bottom halves are
+ * connection_established, iucv_path_severed, local_interrupt_buffer
+ * and receive_ready. The first three can be protected by
+ * priv_lock.  receive_ready is atomic, so it can be incremented and
+ * decremented without holding a lock.
+ * The variable dev_in_use needs to be protected by the lock, since
+ * it's a flag used by open to make sure that the device is opened only
+ * by one user at the same time.
+ */
+struct vmlogrdr_priv_t {
+        char system_service[8];
+        char internal_name[8];
+        char recording_name[8];
+        u16 pathid;
+        int connection_established;
+        int iucv_path_severed;
+        iucv_MessagePending local_interrupt_buffer;
+        atomic_t receive_ready;
+        iucv_handle_t iucv_handle;
+        int minor_num;
+        char * buffer;
+        char * current_position;
+        int remaining;
+        ulong residual_length;
+        int buffer_free;
+        int dev_in_use; /* 1: already opened, 0: not opened*/
+        spinlock_t priv_lock;
+        struct device  *device;
+        struct class_device  *class_device;
+        int autorecording;
+        int autopurge;
+};
+
+
+/*
+ * File operation structure for vmlogrdr devices
+ */
+static int vmlogrdr_open(struct inode *, struct file *);
+static int vmlogrdr_release(struct inode *, struct file *);
+static ssize_t vmlogrdr_read (struct file *filp, char *data, size_t count,
+                               loff_t * ppos);
+
+static struct file_operations vmlogrdr_fops = {
+        .owner   = THIS_MODULE,
+        .open    = vmlogrdr_open,
+        .release = vmlogrdr_release,
+        .read    = vmlogrdr_read,
+};
+
+
+static u8 iucvMagic[16] = {
+        0xF0, 0x40, 0x40, 0x40, 0x40, 0x40, 0x40, 0x40,
+        0xF0, 0x40, 0x40, 0x40, 0x40, 0x40, 0x40, 0x40
+};
+
+
+static u8 mask[] = {
+        0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff,
+        0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff,
+        0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff,
+        0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff
+};
+
+
+static u8 iucv_host[8] = { 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00 };
+
+
+static void
+vmlogrdr_iucv_ConnectionComplete(iucv_ConnectionComplete *eib, void *pgm_data);
+static void
+vmlogrdr_iucv_ConnectionSevered(iucv_ConnectionSevered *eib, void *pgm_data);
+static void
+vmlogrdr_iucv_MessagePending(iucv_MessagePending *eib, void *pgm_data);
+
+
+static iucv_interrupt_ops_t vmlogrdr_iucvops = {
+        .ConnectionComplete = vmlogrdr_iucv_ConnectionComplete,
+        .ConnectionSevered  = vmlogrdr_iucv_ConnectionSevered,
+        .MessagePending     = vmlogrdr_iucv_MessagePending,
+};
+
+
+DECLARE_WAIT_QUEUE_HEAD(conn_wait_queue);
+DECLARE_WAIT_QUEUE_HEAD(read_wait_queue);
+
+/*
+ * pointer to system service private structure
+ * minor number 0 --> logrec
+ * minor number 1 --> account
+ * minor number 2 --> symptom
+ */
+
+static struct vmlogrdr_priv_t sys_ser[] = {
+        { .system_service = "*LOGREC ",
+          .internal_name  = "logrec",
+          .recording_name = "EREP",
+          .minor_num      = 0,
+          .buffer_free    = 1,
+          .priv_lock      = SPIN_LOCK_UNLOCKED,
+          .autorecording  = 1,
+          .autopurge      = 1,
+        },
+        { .system_service = "*ACCOUNT",
+          .internal_name  = "account",
+          .recording_name = "ACCOUNT",
+          .minor_num      = 1,
+          .buffer_free    = 1,
+          .priv_lock      = SPIN_LOCK_UNLOCKED,
+          .autorecording  = 1,
+          .autopurge      = 1,
+        },
+        { .system_service = "*SYMPTOM",
+          .internal_name  = "symptom",
+          .recording_name = "SYMPTOM",
+          .minor_num      = 2,
+          .buffer_free    = 1,
+          .priv_lock      = SPIN_LOCK_UNLOCKED,
+          .autorecording  = 1,
+          .autopurge      = 1,
+        }
+};
+
+#define MAXMINOR  (sizeof(sys_ser)/sizeof(struct vmlogrdr_priv_t))
+
+static char FENCE[] = {"EOR"};
+static int vmlogrdr_major = 0;
+static struct cdev  *vmlogrdr_cdev = NULL;
+static int recording_class_AB;
+
+
+static void
+vmlogrdr_iucv_ConnectionComplete (iucv_ConnectionComplete * eib,
+                                   void * pgm_data)
+{
+        struct vmlogrdr_priv_t * logptr = pgm_data;
+        spin_lock(&logptr->priv_lock);
+        logptr->connection_established = 1;
+        spin_unlock(&logptr->priv_lock);
+        wake_up(&conn_wait_queue);
+        return;
+}
+
+
+static void
+vmlogrdr_iucv_ConnectionSevered (iucv_ConnectionSevered * eib, void * pgm_data)
+{
+        u8 reason = (u8) eib->ipuser[8];
+        struct vmlogrdr_priv_t * logptr = pgm_data;
+
+        printk (KERN_ERR "vmlogrdr: connection severed with"
+                " reason %i\n", reason);
+
+        spin_lock(&logptr->priv_lock);
+        logptr->connection_established = 0;
+        logptr->iucv_path_severed = 1;
+        spin_unlock(&logptr->priv_lock);
+
+        wake_up(&conn_wait_queue);
+        /* just in case we're sleeping waiting for a record */
+        wake_up_interruptible(&read_wait_queue);
+}
+
+
+static void
+vmlogrdr_iucv_MessagePending (iucv_MessagePending * eib, void * pgm_data)
+{
+        struct vmlogrdr_priv_t * logptr = pgm_data;
+
+        /*
+         * This function is the bottom half so it should be quick.
+         * Copy the external interrupt data into our local eib and increment
+         * the usage count
+         */
+        spin_lock(&logptr->priv_lock);
+        memcpy(&(logptr->local_interrupt_buffer), eib, sizeof(*eib));
+        atomic_inc(&logptr->receive_ready);
+        spin_unlock(&logptr->priv_lock);
+        wake_up_interruptible(&read_wait_queue);
+}
+
+
+static int
+vmlogrdr_get_recording_class_AB(void) {
+        char cp_command[]="QUERY COMMAND RECORDING ";
+        char cp_response[80];
+        char *tail;
+        int len,i;
+
+        printk (KERN_DEBUG "vmlogrdr: query command: %s\n", cp_command);
+        cpcmd(cp_command, cp_response, sizeof(cp_response));
+        printk (KERN_DEBUG "vmlogrdr: response: %s", cp_response);
+        len = strnlen(cp_response,sizeof(cp_response));
+        // now the parsing
+        tail=strnchr(cp_response,len,'=');
+        if (!tail)
+                return 0;
+        tail++;
+        if (!strncmp("ANY",tail,3))
+                return 1;
+        if (!strncmp("NONE",tail,4))
+                return 0;
+        /*
+         * expect comma separated list of classes here, if one of them
+         * is A or B return 1 otherwise 0
+         */
+        for (i=tail-cp_response; i<len; i++)
+                if ( cp_response[i]=='A' || cp_response[i]=='B' )
+                        return 1;
+        return 0;
+}
+
+
+static int
+vmlogrdr_recording(struct vmlogrdr_priv_t * logptr, int action, int purge) {
+
+        char cp_command[80];
+        char cp_response[160];
+        char *onoff, *qid_string;
+
+        memset(cp_command, 0x00, sizeof(cp_command));
+        memset(cp_response, 0x00, sizeof(cp_response));
+
+        onoff = ((action == 1) ? "ON" : "OFF");
+        qid_string = ((recording_class_AB == 1) ? " QID * " : "");
+
+        /*
+         * The recording commands needs to be called with option QID
+         * for guests that have previlege classes A or B.
+         * Purging has to be done as separate step, because recording
+         * can't be switched on as long as records are on the queue.
+         * Doing both at the same time doesn't work.
+         */
+
+        if (purge) {
+                snprintf(cp_command, sizeof(cp_command),
+                         "RECORDING %s PURGE %s",
+                         logptr->recording_name,
+                         qid_string);
+
+                printk (KERN_DEBUG "vmlogrdr: recording command: %s\n",
+                        cp_command);
+                cpcmd(cp_command, cp_response, sizeof(cp_response));
+                printk (KERN_DEBUG "vmlogrdr: recording response: %s",
+                        cp_response);
+        }
+
+        memset(cp_command, 0x00, sizeof(cp_command));
+        memset(cp_response, 0x00, sizeof(cp_response));
+        snprintf(cp_command, sizeof(cp_command), "RECORDING %s %s %s",
+                logptr->recording_name,
+                onoff,
+                qid_string);
+
+        printk (KERN_DEBUG "vmlogrdr: recording command: %s\n", cp_command);
+        cpcmd(cp_command, cp_response, sizeof(cp_response));
+        printk (KERN_DEBUG "vmlogrdr: recording response: %s",
+                cp_response);
+        /* The recording command will usually answer with 'Command complete'
+         * on success, but when the specific service was never connected
+         * before then there might be an additional informational message
+         * 'HCPCRC8072I Recording entry not found' before the
+         * 'Command complete'. So I use strstr rather then the strncmp.
+         */
+        if (strstr(cp_response,"Command complete"))
+                return 0;
+        else
+                return -EIO;
+
+}
+
+
+static int
+vmlogrdr_open (struct inode *inode, struct file *filp)
+{
+        int dev_num = 0;
+        struct vmlogrdr_priv_t * logptr = NULL;
+        int connect_rc = 0;
+        int ret;
+
+        dev_num = iminor(inode);
+        if (dev_num > MAXMINOR)
+                return -ENODEV;
+
+        logptr = &sys_ser[dev_num];
+        if (logptr == NULL)
+                return -ENODEV;
+
+        /*
+         * only allow for blocking reads to be open
+         */
+        if (filp->f_flags & O_NONBLOCK)
+                return -ENOSYS;
+
+        /* Besure this device hasn't already been opened */
+        spin_lock_bh(&logptr->priv_lock);
+        if (logptr->dev_in_use) {
+                spin_unlock_bh(&logptr->priv_lock);
+                return -EBUSY;
+        } else {
+                logptr->dev_in_use = 1;
+                spin_unlock_bh(&logptr->priv_lock);
+        }
+
+        atomic_set(&logptr->receive_ready, 0);
+        logptr->buffer_free = 1;
+
+        /* set the file options */
+        filp->private_data = logptr;
+        filp->f_op = &vmlogrdr_fops;
+
+        /* start recording for this service*/
+        ret=0;
+        if (logptr->autorecording)
+                ret = vmlogrdr_recording(logptr,1,logptr->autopurge);
+        if (ret)
+                printk (KERN_WARNING "vmlogrdr: failed to start "
+                        "recording automatically\n");
+
+        /* Register with iucv driver */
+        logptr->iucv_handle = iucv_register_program(iucvMagic,
+                        logptr->system_service, mask, &vmlogrdr_iucvops,
+                        logptr);
+
+        if (logptr->iucv_handle == NULL) {
+                printk (KERN_ERR "vmlogrdr: failed to register with"
+                        "iucv driver\n");
+                goto not_registered;
+        }
+
+        /* create connection to the system service */
+        spin_lock_bh(&logptr->priv_lock);
+        logptr->connection_established = 0;
+        logptr->iucv_path_severed = 0;
+        spin_unlock_bh(&logptr->priv_lock);
+
+        connect_rc = iucv_connect (&(logptr->pathid), 10, iucvMagic,
+                                        logptr->system_service, iucv_host, 0,
+                                        NULL, NULL,
+                                        logptr->iucv_handle, NULL);
+        if (connect_rc) {
+                printk (KERN_ERR "vmlogrdr: iucv connection to %s "
+                        "failed with rc %i \n", logptr->system_service,
+                        connect_rc);
+                goto not_connected;
+        }
+
+        /* We've issued the connect and now we must wait for a
+         * ConnectionComplete or ConnectinSevered Interrupt
+         * before we can continue to process.
+         */
+        wait_event(conn_wait_queue, (logptr->connection_established)
+                   || (logptr->iucv_path_severed));
+        if (logptr->iucv_path_severed) {
+                goto not_connected;
+        }
+
+        return nonseekable_open(inode, filp);
+
+not_connected:
+        iucv_unregister_program(logptr->iucv_handle);
+        logptr->iucv_handle = NULL;
+not_registered:
+        if (logptr->autorecording)
+                vmlogrdr_recording(logptr,0,logptr->autopurge);
+        logptr->dev_in_use = 0;
+        return -EIO;
+
+
+}
+
+
+static int
+vmlogrdr_release (struct inode *inode, struct file *filp)
+{
+        int ret;
+
+        struct vmlogrdr_priv_t * logptr = filp->private_data;
+
+        iucv_unregister_program(logptr->iucv_handle);
+        logptr->iucv_handle = NULL;
+
+        if (logptr->autorecording) {
+                ret = vmlogrdr_recording(logptr,0,logptr->autopurge);
+                if (ret)
+                        printk (KERN_WARNING "vmlogrdr: failed to stop "
+                                "recording automatically\n");
+        }
+        logptr->dev_in_use = 0;
+
+        return 0;
+}
+
+
+static int
+vmlogrdr_receive_data(struct vmlogrdr_priv_t *priv) {
+        int rc, *temp;
+        /* we need to keep track of two data sizes here:
+         * The number of bytes we need to receive from iucv and
+         * the total number of bytes we actually write into the buffer.
+         */
+        int user_data_count, iucv_data_count;
+        char * buffer;
+
+        if (atomic_read(&priv->receive_ready)) {
+                spin_lock_bh(&priv->priv_lock);
+                if (priv->residual_length){
+                        /* receive second half of a record */
+                        iucv_data_count = priv->residual_length;
+                        user_data_count = 0;
+                        buffer = priv->buffer;
+                } else {
+                        /* receive a new record:
+                         * We need to return the total length of the record
+                         * + size of FENCE in the first 4 bytes of the buffer.
+                         */
+                        iucv_data_count =
+                                priv->local_interrupt_buffer.ln1msg2.ipbfln1f;
+                        user_data_count = sizeof(int);
+                        temp = (int*)priv->buffer;
+                        *temp= iucv_data_count + sizeof(FENCE);
+                        buffer = priv->buffer + sizeof(int);
+                }
+                /*
+                 * If the record is bigger then our buffer, we receive only
+                 * a part of it. We can get the rest later.
+                 */
+                if (iucv_data_count > NET_BUFFER_SIZE)
+                        iucv_data_count = NET_BUFFER_SIZE;
+                rc = iucv_receive(priv->pathid,
+                                  priv->local_interrupt_buffer.ipmsgid,
+                                  priv->local_interrupt_buffer.iptrgcls,
+                                  buffer,
+                                  iucv_data_count,
+                                  NULL,
+                                  NULL,
+                                  &priv->residual_length);
+                spin_unlock_bh(&priv->priv_lock);
+                /* An rc of 5 indicates that the record was bigger then
+                 * the buffer, which is OK for us. A 9 indicates that the
+                 * record was purged befor we could receive it.
+                 */
+                if (rc == 5)
+                        rc = 0;
+                if (rc == 9)
+                        atomic_set(&priv->receive_ready, 0);
+        } else {
+                rc = 1;
+        }
+        if (!rc) {
+                priv->buffer_free = 0;
+                user_data_count += iucv_data_count;
+                priv->current_position = priv->buffer;
+                if (priv->residual_length == 0){
+                        /* the whole record has been captured,
+                         * now add the fence */
+                        atomic_dec(&priv->receive_ready);
+                        buffer = priv->buffer + user_data_count;
+                        memcpy(buffer, FENCE, sizeof(FENCE));
+                        user_data_count += sizeof(FENCE);
+                }
+                priv->remaining = user_data_count;
+        }
+
+        return rc;
+}
+
+
+static ssize_t
+vmlogrdr_read (struct file *filp, char *data, size_t count, loff_t * ppos)
+{
+        int rc;
+        struct vmlogrdr_priv_t * priv = filp->private_data;
+
+        while (priv->buffer_free) {
+                rc = vmlogrdr_receive_data(priv);
+                if (rc) {
+                        rc = wait_event_interruptible(read_wait_queue,
+                                        atomic_read(&priv->receive_ready));
+                        if (rc)
+                                return rc;
+                }
+        }
+        /* copy only up to end of record */
+        if (count > priv->remaining)
+                count = priv->remaining;
+
+        if (copy_to_user(data, priv->current_position, count))
+                return -EFAULT;
+
+        *ppos += count;
+        priv->current_position += count;
+        priv->remaining -= count;
+
+        /* if all data has been transferred, set buffer free */
+        if (priv->remaining == 0)
+                priv->buffer_free = 1;
+
+        return count;
+}
+
+static ssize_t
+vmlogrdr_autopurge_store(struct device * dev, const char * buf, size_t count) {
+        struct vmlogrdr_priv_t *priv = dev->driver_data;
+        ssize_t ret = count;
+
+        switch (buf[0]) {
+        case '0':
+                priv->autopurge=0;
+                break;
+        case '1':
+                priv->autopurge=1;
+                break;
+        default:
+                ret = -EINVAL;
+        }
+        return ret;
+}
+
+
+static ssize_t
+vmlogrdr_autopurge_show(struct device *dev, char *buf) {
+        struct vmlogrdr_priv_t *priv = dev->driver_data;
+        return sprintf(buf, "%u\n", priv->autopurge);
+}
+
+
+static DEVICE_ATTR(autopurge, 0644, vmlogrdr_autopurge_show,
+                   vmlogrdr_autopurge_store);
+
+
+static ssize_t
+vmlogrdr_purge_store(struct device * dev, const char * buf, size_t count) {
+
+        char cp_command[80];
+        char cp_response[80];
+        struct vmlogrdr_priv_t *priv = dev->driver_data;
+
+        if (buf[0] != '1')
+                return -EINVAL;
+
+        memset(cp_command, 0x00, sizeof(cp_command));
+        memset(cp_response, 0x00, sizeof(cp_response));
+
+        /*
+         * The recording command needs to be called with option QID
+         * for guests that have previlege classes A or B.
+         * Other guests will not recognize the command and we have to
+         * issue the same command without the QID parameter.
+         */
+
+        if (recording_class_AB)
+                snprintf(cp_command, sizeof(cp_command),
+                         "RECORDING %s PURGE QID * ",
+                         priv->recording_name);
+        else
+                snprintf(cp_command, sizeof(cp_command),
+                         "RECORDING %s PURGE ",
+                         priv->recording_name);
+
+        printk (KERN_DEBUG "vmlogrdr: recording command: %s\n", cp_command);
+        cpcmd(cp_command, cp_response, sizeof(cp_response));
+        printk (KERN_DEBUG "vmlogrdr: recording response: %s",
+                cp_response);
+
+        return count;
+}
+
+
+static DEVICE_ATTR(purge, 0200, NULL, vmlogrdr_purge_store);
+
+
+static ssize_t
+vmlogrdr_autorecording_store(struct device *dev, const char *buf,
+                             size_t count) {
+        struct vmlogrdr_priv_t *priv = dev->driver_data;
+        ssize_t ret = count;
+
+        switch (buf[0]) {
+        case '0':
+                priv->autorecording=0;
+                break;
+        case '1':
+                priv->autorecording=1;
+                break;
+        default:
+                ret = -EINVAL;
+        }
+        return ret;
+}
+
+
+static ssize_t
+vmlogrdr_autorecording_show(struct device *dev, char *buf) {
+        struct vmlogrdr_priv_t *priv = dev->driver_data;
+        return sprintf(buf, "%u\n", priv->autorecording);
+}
+
+
+static DEVICE_ATTR(autorecording, 0644, vmlogrdr_autorecording_show,
+                   vmlogrdr_autorecording_store);
+
+
+static ssize_t
+vmlogrdr_recording_store(struct device * dev, const char * buf, size_t count) {
+
+        struct vmlogrdr_priv_t *priv = dev->driver_data;
+        ssize_t ret;
+
+        switch (buf[0]) {
+        case '0':
+                ret = vmlogrdr_recording(priv,0,0);
+                break;
+        case '1':
+                ret = vmlogrdr_recording(priv,1,0);
+                break;
+        default:
+                ret = -EINVAL;
+        }
+        if (ret)
+                return ret;
+        else
+                return count;
+
+}
+
+
+static DEVICE_ATTR(recording, 0200, NULL, vmlogrdr_recording_store);
+
+
+static ssize_t
+vmlogrdr_recording_status_show(struct device_driver *driver, char *buf) {
+
+        char cp_command[] = "QUERY RECORDING ";
+        int len;
+
+        cpcmd(cp_command, buf, 4096);
+        len = strlen(buf);
+        return len;
+}
+
+
+static DRIVER_ATTR(recording_status, 0444, vmlogrdr_recording_status_show,
+                   NULL);
+
+static struct attribute *vmlogrdr_attrs[] = {
+        &dev_attr_autopurge.attr,
+        &dev_attr_purge.attr,
+        &dev_attr_autorecording.attr,
+        &dev_attr_recording.attr,
+        NULL,
+};
+
+static struct attribute_group vmlogrdr_attr_group = {
+        .attrs = vmlogrdr_attrs,
+};
+
+static struct class_simple *vmlogrdr_class;
+static struct device_driver vmlogrdr_driver = {
+        .name = "vmlogrdr",
+        .bus  = &iucv_bus,
+};
+
+
+static int
+vmlogrdr_register_driver(void) {
+        int ret;
+
+        ret = driver_register(&vmlogrdr_driver);
+        if (ret) {
+                printk(KERN_ERR "vmlogrdr: failed to register driver.\n");
+                return ret;
+        }
+
+        ret = driver_create_file(&vmlogrdr_driver,
+                                 &driver_attr_recording_status);
+        if (ret) {
+                printk(KERN_ERR "vmlogrdr: failed to add driver attribute.\n");
+                goto unregdriver;
+        }
+
+        vmlogrdr_class = class_simple_create(THIS_MODULE, "vmlogrdr");
+        if (IS_ERR(vmlogrdr_class)) {
+                printk(KERN_ERR "vmlogrdr: failed to create class.\n");
+                ret=PTR_ERR(vmlogrdr_class);
+                vmlogrdr_class=NULL;
+                goto unregattr;
+        }
+        return 0;
+
+unregattr:
+        driver_remove_file(&vmlogrdr_driver, &driver_attr_recording_status);
+unregdriver:
+        driver_unregister(&vmlogrdr_driver);
+        return ret;
+}
+
+
+static void
+vmlogrdr_unregister_driver(void) {
+        class_simple_destroy(vmlogrdr_class);
+        vmlogrdr_class = NULL;
+        driver_remove_file(&vmlogrdr_driver, &driver_attr_recording_status);
+        driver_unregister(&vmlogrdr_driver);
+        return;
+}
+
+
+static int
+vmlogrdr_register_device(struct vmlogrdr_priv_t *priv) {
+        struct device *dev;
+        int ret;
+
+        dev = kmalloc(sizeof(struct device), GFP_KERNEL);
+        if (dev) {
+                memset(dev, 0, sizeof(struct device));
+                snprintf(dev->bus_id, BUS_ID_SIZE, "%s",
+                         priv->internal_name);
+                dev->bus = &iucv_bus;
+                dev->parent = iucv_root;
+                dev->driver = &vmlogrdr_driver;
+                /*
+                 * The release function could be called after the
+                 * module has been unloaded. It's _only_ task is to
+                 * free the struct. Therefore, we specify kfree()
+                 * directly here. (Probably a little bit obfuscating
+                 * but legitime ...).
+                 */
+                dev->release = (void (*)(struct device *))kfree;
+        } else
+                return -ENOMEM;
+        ret = device_register(dev);
+        if (ret)
+                return ret;
+
+        ret = sysfs_create_group(&dev->kobj, &vmlogrdr_attr_group);
+        if (ret) {
+                device_unregister(dev);
+                return ret;
+        }
+        priv->class_device = class_simple_device_add(
+                                vmlogrdr_class,
+                                MKDEV(vmlogrdr_major, priv->minor_num),
+                                dev,
+                                "%s", dev->bus_id );
+        if (IS_ERR(priv->class_device)) {
+                ret = PTR_ERR(priv->class_device);
+                priv->class_device=NULL;
+                sysfs_remove_group(&dev->kobj, &vmlogrdr_attr_group);
+                device_unregister(dev);
+                return ret;
+        }
+        dev->driver_data = priv;
+        priv->device = dev;
+        return 0;
+}
+
+
+static int
+vmlogrdr_unregister_device(struct vmlogrdr_priv_t *priv ) {
+        class_simple_device_remove(MKDEV(vmlogrdr_major, priv->minor_num));
+        if (priv->device != NULL) {
+                sysfs_remove_group(&priv->device->kobj, &vmlogrdr_attr_group);
+                device_unregister(priv->device);
+                priv->device=NULL;
+        }
+        return 0;
+}
+
+
+static int
+vmlogrdr_register_cdev(dev_t dev) {
+        int rc = 0;
+        vmlogrdr_cdev = cdev_alloc();
+        if (!vmlogrdr_cdev) {
+                return -ENOMEM;
+        }
+        vmlogrdr_cdev->owner = THIS_MODULE;
+        vmlogrdr_cdev->ops = &vmlogrdr_fops;
+        vmlogrdr_cdev->dev = dev;
+        rc = cdev_add(vmlogrdr_cdev, vmlogrdr_cdev->dev, MAXMINOR);
+        if (!rc)
+                return 0;
+
+        // cleanup: cdev is not fully registered, no cdev_del here!
+        kobject_put(&vmlogrdr_cdev->kobj);
+        vmlogrdr_cdev=NULL;
+        return rc;
+}
+
+
+static void
+vmlogrdr_cleanup(void) {
+        int i;
+        if (vmlogrdr_cdev) {
+                cdev_del(vmlogrdr_cdev);
+                vmlogrdr_cdev=NULL;
+        }
+        for (i=0; i < MAXMINOR; ++i ) {
+                vmlogrdr_unregister_device(&sys_ser[i]);
+                free_page((unsigned long)sys_ser[i].buffer);
+        }
+        vmlogrdr_unregister_driver();
+        if (vmlogrdr_major) {
+                unregister_chrdev_region(MKDEV(vmlogrdr_major, 0), MAXMINOR);
+                vmlogrdr_major=0;
+        }
+}
+
+
+static int
+vmlogrdr_init(void)
+{
+        int rc;
+        int i;
+        dev_t dev;
+
+        if (! MACHINE_IS_VM) {
+                printk (KERN_ERR "vmlogrdr: not running under VM, "
+                                "driver not loaded.\n");
+                return -ENODEV;
+        }
+
+        recording_class_AB = vmlogrdr_get_recording_class_AB();
+
+        rc = alloc_chrdev_region(&dev, 0, MAXMINOR, "vmlogrdr");
+        if (rc)
+                return rc;
+        vmlogrdr_major = MAJOR(dev);
+
+        rc=vmlogrdr_register_driver();
+        if (rc)
+                goto cleanup;
+
+        for (i=0; i < MAXMINOR; ++i ) {
+                sys_ser[i].buffer = (char *) get_zeroed_page(GFP_KERNEL);
+                if (!sys_ser[i].buffer) {
+                        rc = ENOMEM;
+                        break;
+                }
+                sys_ser[i].current_position = sys_ser[i].buffer;
+                rc=vmlogrdr_register_device(&sys_ser[i]);
+                if (rc)
+                        break;
+        }
+        if (rc)
+                goto cleanup;
+
+        rc = vmlogrdr_register_cdev(dev);
+        if (rc)
+                goto cleanup;
+        printk (KERN_INFO "vmlogrdr: driver loaded\n");
+        return 0;
+
+cleanup:
+        vmlogrdr_cleanup();
+        printk (KERN_ERR "vmlogrdr: driver not loaded.\n");
+        return rc;
+}
+
+
+static void
+vmlogrdr_exit(void)
+{
+        vmlogrdr_cleanup();
+        printk (KERN_INFO "vmlogrdr: driver unloaded\n");
+        return;
+}
+
+
+module_init(vmlogrdr_init);
+module_exit(vmlogrdr_exit);