git.oblomov.eu Git - linux-2.6/blob - drivers/s390/char/vmlogrdr.c

   1 /*
   2  * drivers/s390/char/vmlogrdr.c
   3  *      character device driver for reading z/VM system service records
   4  *
   5  *
   6  *      Copyright 2004 IBM Corporation
   7  *      character device driver for reading z/VM system service records,
   8  *      Version 1.0
   9  *      Author(s): Xenia Tkatschow <xenia@us.ibm.com>
  10  *                 Stefan Weinhuber <wein@de.ibm.com>
  11  *
  12  */
  13
  14 #define KMSG_COMPONENT "vmlogrdr"
  15 #define pr_fmt(fmt) KMSG_COMPONENT ": " fmt
  16
  17 #include <linux/module.h>
  18 #include <linux/init.h>
  19 #include <linux/errno.h>
  20 #include <linux/types.h>
  21 #include <linux/interrupt.h>
  22 #include <linux/spinlock.h>
  23 #include <asm/atomic.h>
  24 #include <asm/uaccess.h>
  25 #include <asm/cpcmd.h>
  26 #include <asm/debug.h>
  27 #include <asm/ebcdic.h>
  28 #include <net/iucv/iucv.h>
  29 #include <linux/kmod.h>
  30 #include <linux/cdev.h>
  31 #include <linux/device.h>
  32 #include <linux/smp_lock.h>
  33 #include <linux/string.h>
  34
  35 MODULE_AUTHOR
  36         ("(C) 2004 IBM Corporation by Xenia Tkatschow (xenia@us.ibm.com)\n"
  37          "                            Stefan Weinhuber (wein@de.ibm.com)");
  38 MODULE_DESCRIPTION ("Character device driver for reading z/VM "
  39                     "system service records.");
  40 MODULE_LICENSE("GPL");
  41
  42
  43 /*
  44  * The size of the buffer for iucv data transfer is one page,
  45  * but in addition to the data we read from iucv we also
  46  * place an integer and some characters into that buffer,
  47  * so the maximum size for record data is a little less then
  48  * one page.
  49  */
  50 #define NET_BUFFER_SIZE (PAGE_SIZE - sizeof(int) - sizeof(FENCE))
  51
  52 /*
  53  * The elements that are concurrently accessed by bottom halves are
  54  * connection_established, iucv_path_severed, local_interrupt_buffer
  55  * and receive_ready. The first three can be protected by
  56  * priv_lock.  receive_ready is atomic, so it can be incremented and
  57  * decremented without holding a lock.
  58  * The variable dev_in_use needs to be protected by the lock, since
  59  * it's a flag used by open to make sure that the device is opened only
  60  * by one user at the same time.
  61  */
  62 struct vmlogrdr_priv_t {
  63         char system_service[8];
  64         char internal_name[8];
  65         char recording_name[8];
  66         struct iucv_path *path;
  67         int connection_established;
  68         int iucv_path_severed;
  69         struct iucv_message local_interrupt_buffer;
  70         atomic_t receive_ready;
  71         int minor_num;
  72         char * buffer;
  73         char * current_position;
  74         int remaining;
  75         ulong residual_length;
  76         int buffer_free;
  77         int dev_in_use; /* 1: already opened, 0: not opened*/
  78         spinlock_t priv_lock;
  79         struct device  *device;
  80         struct device  *class_device;
  81         int autorecording;
  82         int autopurge;
  83 };
  84
  85
  86 /*
  87  * File operation structure for vmlogrdr devices
  88  */
  89 static int vmlogrdr_open(struct inode *, struct file *);
  90 static int vmlogrdr_release(struct inode *, struct file *);
  91 static ssize_t vmlogrdr_read (struct file *filp, char __user *data,
  92                               size_t count, loff_t * ppos);
  93
  94 static const struct file_operations vmlogrdr_fops = {
  95         .owner   = THIS_MODULE,
  96         .open    = vmlogrdr_open,
  97         .release = vmlogrdr_release,
  98         .read    = vmlogrdr_read,
  99 };
 100
 101
 102 static void vmlogrdr_iucv_path_complete(struct iucv_path *, u8 ipuser[16]);
 103 static void vmlogrdr_iucv_path_severed(struct iucv_path *, u8 ipuser[16]);
 104 static void vmlogrdr_iucv_message_pending(struct iucv_path *,
 105                                           struct iucv_message *);
 106
 107
 108 static struct iucv_handler vmlogrdr_iucv_handler = {
 109         .path_complete   = vmlogrdr_iucv_path_complete,
 110         .path_severed    = vmlogrdr_iucv_path_severed,
 111         .message_pending = vmlogrdr_iucv_message_pending,
 112 };
 113
 114
 115 static DECLARE_WAIT_QUEUE_HEAD(conn_wait_queue);
 116 static DECLARE_WAIT_QUEUE_HEAD(read_wait_queue);
 117
 118 /*
 119  * pointer to system service private structure
 120  * minor number 0 --> logrec
 121  * minor number 1 --> account
 122  * minor number 2 --> symptom
 123  */
 124
 125 static struct vmlogrdr_priv_t sys_ser[] = {
 126         { .system_service = "*LOGREC ",
 127           .internal_name  = "logrec",
 128           .recording_name = "EREP",
 129           .minor_num      = 0,
 130           .buffer_free    = 1,
 131           .priv_lock      = __SPIN_LOCK_UNLOCKED(sys_ser[0].priv_lock),
 132           .autorecording  = 1,
 133           .autopurge      = 1,
 134         },
 135         { .system_service = "*ACCOUNT",
 136           .internal_name  = "account",
 137           .recording_name = "ACCOUNT",
 138           .minor_num      = 1,
 139           .buffer_free    = 1,
 140           .priv_lock      = __SPIN_LOCK_UNLOCKED(sys_ser[1].priv_lock),
 141           .autorecording  = 1,
 142           .autopurge      = 1,
 143         },
 144         { .system_service = "*SYMPTOM",
 145           .internal_name  = "symptom",
 146           .recording_name = "SYMPTOM",
 147           .minor_num      = 2,
 148           .buffer_free    = 1,
 149           .priv_lock      = __SPIN_LOCK_UNLOCKED(sys_ser[2].priv_lock),
 150           .autorecording  = 1,
 151           .autopurge      = 1,
 152         }
 153 };
 154
 155 #define MAXMINOR  (sizeof(sys_ser)/sizeof(struct vmlogrdr_priv_t))
 156
 157 static char FENCE[] = {"EOR"};
 158 static int vmlogrdr_major = 0;
 159 static struct cdev  *vmlogrdr_cdev = NULL;
 160 static int recording_class_AB;
 161
 162
 163 static void vmlogrdr_iucv_path_complete(struct iucv_path *path, u8 ipuser[16])
 164 {
 165         struct vmlogrdr_priv_t * logptr = path->private;
 166
 167         spin_lock(&logptr->priv_lock);
 168         logptr->connection_established = 1;
 169         spin_unlock(&logptr->priv_lock);
 170         wake_up(&conn_wait_queue);
 171 }
 172
 173
 174 static void vmlogrdr_iucv_path_severed(struct iucv_path *path, u8 ipuser[16])
 175 {
 176         struct vmlogrdr_priv_t * logptr = path->private;
 177         u8 reason = (u8) ipuser[8];
 178
 179         pr_err("vmlogrdr: connection severed with reason %i\n", reason);
 180
 181         iucv_path_sever(path, NULL);
 182         kfree(path);
 183         logptr->path = NULL;
 184
 185         spin_lock(&logptr->priv_lock);
 186         logptr->connection_established = 0;
 187         logptr->iucv_path_severed = 1;
 188         spin_unlock(&logptr->priv_lock);
 189
 190         wake_up(&conn_wait_queue);
 191         /* just in case we're sleeping waiting for a record */
 192         wake_up_interruptible(&read_wait_queue);
 193 }
 194
 195
 196 static void vmlogrdr_iucv_message_pending(struct iucv_path *path,
 197                                           struct iucv_message *msg)
 198 {
 199         struct vmlogrdr_priv_t * logptr = path->private;
 200
 201         /*
 202          * This function is the bottom half so it should be quick.
 203          * Copy the external interrupt data into our local eib and increment
 204          * the usage count
 205          */
 206         spin_lock(&logptr->priv_lock);
 207         memcpy(&logptr->local_interrupt_buffer, msg, sizeof(*msg));
 208         atomic_inc(&logptr->receive_ready);
 209         spin_unlock(&logptr->priv_lock);
 210         wake_up_interruptible(&read_wait_queue);
 211 }
 212
 213
 214 static int vmlogrdr_get_recording_class_AB(void)
 215 {
 216         char cp_command[]="QUERY COMMAND RECORDING ";
 217         char cp_response[80];
 218         char *tail;
 219         int len,i;
 220
 221         cpcmd(cp_command, cp_response, sizeof(cp_response), NULL);
 222         len = strnlen(cp_response,sizeof(cp_response));
 223         // now the parsing
 224         tail=strnchr(cp_response,len,'=');
 225         if (!tail)
 226                 return 0;
 227         tail++;
 228         if (!strncmp("ANY",tail,3))
 229                 return 1;
 230         if (!strncmp("NONE",tail,4))
 231                 return 0;
 232         /*
 233          * expect comma separated list of classes here, if one of them
 234          * is A or B return 1 otherwise 0
 235          */
 236         for (i=tail-cp_response; i<len; i++)
 237                 if ( cp_response[i]=='A' || cp_response[i]=='B' )
 238                         return 1;
 239         return 0;
 240 }
 241
 242
 243 static int vmlogrdr_recording(struct vmlogrdr_priv_t * logptr,
 244                               int action, int purge)
 245 {
 246
 247         char cp_command[80];
 248         char cp_response[160];
 249         char *onoff, *qid_string;
 250
 251         memset(cp_command, 0x00, sizeof(cp_command));
 252         memset(cp_response, 0x00, sizeof(cp_response));
 253
 254         onoff = ((action == 1) ? "ON" : "OFF");
 255         qid_string = ((recording_class_AB == 1) ? " QID * " : "");
 256
 257         /*
 258          * The recording commands needs to be called with option QID
 259          * for guests that have previlege classes A or B.
 260          * Purging has to be done as separate step, because recording
 261          * can't be switched on as long as records are on the queue.
 262          * Doing both at the same time doesn't work.
 263          */
 264
 265         if (purge) {
 266                 snprintf(cp_command, sizeof(cp_command),
 267                          "RECORDING %s PURGE %s",
 268                          logptr->recording_name,
 269                          qid_string);
 270
 271                 cpcmd(cp_command, cp_response, sizeof(cp_response), NULL);
 272         }
 273
 274         memset(cp_command, 0x00, sizeof(cp_command));
 275         memset(cp_response, 0x00, sizeof(cp_response));
 276         snprintf(cp_command, sizeof(cp_command), "RECORDING %s %s %s",
 277                 logptr->recording_name,
 278                 onoff,
 279                 qid_string);
 280
 281         cpcmd(cp_command, cp_response, sizeof(cp_response), NULL);
 282         /* The recording command will usually answer with 'Command complete'
 283          * on success, but when the specific service was never connected
 284          * before then there might be an additional informational message
 285          * 'HCPCRC8072I Recording entry not found' before the
 286          * 'Command complete'. So I use strstr rather then the strncmp.
 287          */
 288         if (strstr(cp_response,"Command complete"))
 289                 return 0;
 290         else
 291                 return -EIO;
 292
 293 }
 294
 295
 296 static int vmlogrdr_open (struct inode *inode, struct file *filp)
 297 {
 298         int dev_num = 0;
 299         struct vmlogrdr_priv_t * logptr = NULL;
 300         int connect_rc = 0;
 301         int ret;
 302
 303         dev_num = iminor(inode);
 304         if (dev_num > MAXMINOR)
 305                 return -ENODEV;
 306         logptr = &sys_ser[dev_num];
 307
 308         /*
 309          * only allow for blocking reads to be open
 310          */
 311         if (filp->f_flags & O_NONBLOCK)
 312                 return -ENOSYS;
 313
 314         /* Besure this device hasn't already been opened */
 315         lock_kernel();
 316         spin_lock_bh(&logptr->priv_lock);
 317         if (logptr->dev_in_use) {
 318                 spin_unlock_bh(&logptr->priv_lock);
 319                 unlock_kernel();
 320                 return -EBUSY;
 321         }
 322         logptr->dev_in_use = 1;
 323         logptr->connection_established = 0;
 324         logptr->iucv_path_severed = 0;
 325         atomic_set(&logptr->receive_ready, 0);
 326         logptr->buffer_free = 1;
 327         spin_unlock_bh(&logptr->priv_lock);
 328
 329         /* set the file options */
 330         filp->private_data = logptr;
 331         filp->f_op = &vmlogrdr_fops;
 332
 333         /* start recording for this service*/
 334         if (logptr->autorecording) {
 335                 ret = vmlogrdr_recording(logptr,1,logptr->autopurge);
 336                 if (ret)
 337                         pr_warning("vmlogrdr: failed to start "
 338                                    "recording automatically\n");
 339         }
 340
 341         /* create connection to the system service */
 342         logptr->path = iucv_path_alloc(10, 0, GFP_KERNEL);
 343         if (!logptr->path)
 344                 goto out_dev;
 345         connect_rc = iucv_path_connect(logptr->path, &vmlogrdr_iucv_handler,
 346                                        logptr->system_service, NULL, NULL,
 347                                        logptr);
 348         if (connect_rc) {
 349                 pr_err("vmlogrdr: iucv connection to %s "
 350                        "failed with rc %i \n",
 351                        logptr->system_service, connect_rc);
 352                 goto out_path;
 353         }
 354
 355         /* We've issued the connect and now we must wait for a
 356          * ConnectionComplete or ConnectinSevered Interrupt
 357          * before we can continue to process.
 358          */
 359         wait_event(conn_wait_queue, (logptr->connection_established)
 360                    || (logptr->iucv_path_severed));
 361         if (logptr->iucv_path_severed)
 362                 goto out_record;
 363         ret = nonseekable_open(inode, filp);
 364         unlock_kernel();
 365         return ret;
 366
 367 out_record:
 368         if (logptr->autorecording)
 369                 vmlogrdr_recording(logptr,0,logptr->autopurge);
 370 out_path:
 371         kfree(logptr->path);    /* kfree(NULL) is ok. */
 372         logptr->path = NULL;
 373 out_dev:
 374         logptr->dev_in_use = 0;
 375         unlock_kernel();
 376         return -EIO;
 377 }
 378
 379
 380 static int vmlogrdr_release (struct inode *inode, struct file *filp)
 381 {
 382         int ret;
 383
 384         struct vmlogrdr_priv_t * logptr = filp->private_data;
 385
 386         iucv_path_sever(logptr->path, NULL);
 387         kfree(logptr->path);
 388         logptr->path = NULL;
 389         if (logptr->autorecording) {
 390                 ret = vmlogrdr_recording(logptr,0,logptr->autopurge);
 391                 if (ret)
 392                         pr_warning("vmlogrdr: failed to stop "
 393                                    "recording automatically\n");
 394         }
 395         logptr->dev_in_use = 0;
 396
 397         return 0;
 398 }
 399
 400
 401 static int vmlogrdr_receive_data(struct vmlogrdr_priv_t *priv)
 402 {
 403         int rc, *temp;
 404         /* we need to keep track of two data sizes here:
 405          * The number of bytes we need to receive from iucv and
 406          * the total number of bytes we actually write into the buffer.
 407          */
 408         int user_data_count, iucv_data_count;
 409         char * buffer;
 410
 411         if (atomic_read(&priv->receive_ready)) {
 412                 spin_lock_bh(&priv->priv_lock);
 413                 if (priv->residual_length){
 414                         /* receive second half of a record */
 415                         iucv_data_count = priv->residual_length;
 416                         user_data_count = 0;
 417                         buffer = priv->buffer;
 418                 } else {
 419                         /* receive a new record:
 420                          * We need to return the total length of the record
 421                          * + size of FENCE in the first 4 bytes of the buffer.
 422                          */
 423                         iucv_data_count = priv->local_interrupt_buffer.length;
 424                         user_data_count = sizeof(int);
 425                         temp = (int*)priv->buffer;
 426                         *temp= iucv_data_count + sizeof(FENCE);
 427                         buffer = priv->buffer + sizeof(int);
 428                 }
 429                 /*
 430                  * If the record is bigger than our buffer, we receive only
 431                  * a part of it. We can get the rest later.
 432                  */
 433                 if (iucv_data_count > NET_BUFFER_SIZE)
 434                         iucv_data_count = NET_BUFFER_SIZE;
 435                 rc = iucv_message_receive(priv->path,
 436                                           &priv->local_interrupt_buffer,
 437                                           0, buffer, iucv_data_count,
 438                                           &priv->residual_length);
 439                 spin_unlock_bh(&priv->priv_lock);
 440                 /* An rc of 5 indicates that the record was bigger than
 441                  * the buffer, which is OK for us. A 9 indicates that the
 442                  * record was purged befor we could receive it.
 443                  */
 444                 if (rc == 5)
 445                         rc = 0;
 446                 if (rc == 9)
 447                         atomic_set(&priv->receive_ready, 0);
 448         } else {
 449                 rc = 1;
 450         }
 451         if (!rc) {
 452                 priv->buffer_free = 0;
 453                 user_data_count += iucv_data_count;
 454                 priv->current_position = priv->buffer;
 455                 if (priv->residual_length == 0){
 456                         /* the whole record has been captured,
 457                          * now add the fence */
 458                         atomic_dec(&priv->receive_ready);
 459                         buffer = priv->buffer + user_data_count;
 460                         memcpy(buffer, FENCE, sizeof(FENCE));
 461                         user_data_count += sizeof(FENCE);
 462                 }
 463                 priv->remaining = user_data_count;
 464         }
 465
 466         return rc;
 467 }
 468
 469
 470 static ssize_t vmlogrdr_read(struct file *filp, char __user *data,
 471                              size_t count, loff_t * ppos)
 472 {
 473         int rc;
 474         struct vmlogrdr_priv_t * priv = filp->private_data;
 475
 476         while (priv->buffer_free) {
 477                 rc = vmlogrdr_receive_data(priv);
 478                 if (rc) {
 479                         rc = wait_event_interruptible(read_wait_queue,
 480                                         atomic_read(&priv->receive_ready));
 481                         if (rc)
 482                                 return rc;
 483                 }
 484         }
 485         /* copy only up to end of record */
 486         if (count > priv->remaining)
 487                 count = priv->remaining;
 488
 489         if (copy_to_user(data, priv->current_position, count))
 490                 return -EFAULT;
 491
 492         *ppos += count;
 493         priv->current_position += count;
 494         priv->remaining -= count;
 495
 496         /* if all data has been transferred, set buffer free */
 497         if (priv->remaining == 0)
 498                 priv->buffer_free = 1;
 499
 500         return count;
 501 }
 502
 503 static ssize_t vmlogrdr_autopurge_store(struct device * dev,
 504                                         struct device_attribute *attr,
 505                                         const char * buf, size_t count)
 506 {
 507         struct vmlogrdr_priv_t *priv = dev->driver_data;
 508         ssize_t ret = count;
 509
 510         switch (buf[0]) {
 511         case '0':
 512                 priv->autopurge=0;
 513                 break;
 514         case '1':
 515                 priv->autopurge=1;
 516                 break;
 517         default:
 518                 ret = -EINVAL;
 519         }
 520         return ret;
 521 }
 522
 523
 524 static ssize_t vmlogrdr_autopurge_show(struct device *dev,
 525                                        struct device_attribute *attr,
 526                                        char *buf)
 527 {
 528         struct vmlogrdr_priv_t *priv = dev->driver_data;
 529         return sprintf(buf, "%u\n", priv->autopurge);
 530 }
 531
 532
 533 static DEVICE_ATTR(autopurge, 0644, vmlogrdr_autopurge_show,
 534                    vmlogrdr_autopurge_store);
 535
 536
 537 static ssize_t vmlogrdr_purge_store(struct device * dev,
 538                                     struct device_attribute *attr,
 539                                     const char * buf, size_t count)
 540 {
 541
 542         char cp_command[80];
 543         char cp_response[80];
 544         struct vmlogrdr_priv_t *priv = dev->driver_data;
 545
 546         if (buf[0] != '1')
 547                 return -EINVAL;
 548
 549         memset(cp_command, 0x00, sizeof(cp_command));
 550         memset(cp_response, 0x00, sizeof(cp_response));
 551
 552         /*
 553          * The recording command needs to be called with option QID
 554          * for guests that have previlege classes A or B.
 555          * Other guests will not recognize the command and we have to
 556          * issue the same command without the QID parameter.
 557          */
 558
 559         if (recording_class_AB)
 560                 snprintf(cp_command, sizeof(cp_command),
 561                          "RECORDING %s PURGE QID * ",
 562                          priv->recording_name);
 563         else
 564                 snprintf(cp_command, sizeof(cp_command),
 565                          "RECORDING %s PURGE ",
 566                          priv->recording_name);
 567
 568         cpcmd(cp_command, cp_response, sizeof(cp_response), NULL);
 569
 570         return count;
 571 }
 572
 573
 574 static DEVICE_ATTR(purge, 0200, NULL, vmlogrdr_purge_store);
 575
 576
 577 static ssize_t vmlogrdr_autorecording_store(struct device *dev,
 578                                             struct device_attribute *attr,
 579                                             const char *buf, size_t count)
 580 {
 581         struct vmlogrdr_priv_t *priv = dev->driver_data;
 582         ssize_t ret = count;
 583
 584         switch (buf[0]) {
 585         case '0':
 586                 priv->autorecording=0;
 587                 break;
 588         case '1':
 589                 priv->autorecording=1;
 590                 break;
 591         default:
 592                 ret = -EINVAL;
 593         }
 594         return ret;
 595 }
 596
 597
 598 static ssize_t vmlogrdr_autorecording_show(struct device *dev,
 599                                            struct device_attribute *attr,
 600                                            char *buf)
 601 {
 602         struct vmlogrdr_priv_t *priv = dev->driver_data;
 603         return sprintf(buf, "%u\n", priv->autorecording);
 604 }
 605
 606
 607 static DEVICE_ATTR(autorecording, 0644, vmlogrdr_autorecording_show,
 608                    vmlogrdr_autorecording_store);
 609
 610
 611 static ssize_t vmlogrdr_recording_store(struct device * dev,
 612                                         struct device_attribute *attr,
 613                                         const char * buf, size_t count)
 614 {
 615         struct vmlogrdr_priv_t *priv = dev->driver_data;
 616         ssize_t ret;
 617
 618         switch (buf[0]) {
 619         case '0':
 620                 ret = vmlogrdr_recording(priv,0,0);
 621                 break;
 622         case '1':
 623                 ret = vmlogrdr_recording(priv,1,0);
 624                 break;
 625         default:
 626                 ret = -EINVAL;
 627         }
 628         if (ret)
 629                 return ret;
 630         else
 631                 return count;
 632
 633 }
 634
 635
 636 static DEVICE_ATTR(recording, 0200, NULL, vmlogrdr_recording_store);
 637
 638
 639 static ssize_t vmlogrdr_recording_status_show(struct device_driver *driver,
 640                                               char *buf)
 641 {
 642
 643         char cp_command[] = "QUERY RECORDING ";
 644         int len;
 645
 646         cpcmd(cp_command, buf, 4096, NULL);
 647         len = strlen(buf);
 648         return len;
 649 }
 650
 651
 652 static DRIVER_ATTR(recording_status, 0444, vmlogrdr_recording_status_show,
 653                    NULL);
 654
 655 static struct attribute *vmlogrdr_attrs[] = {
 656         &dev_attr_autopurge.attr,
 657         &dev_attr_purge.attr,
 658         &dev_attr_autorecording.attr,
 659         &dev_attr_recording.attr,
 660         NULL,
 661 };
 662
 663 static struct attribute_group vmlogrdr_attr_group = {
 664         .attrs = vmlogrdr_attrs,
 665 };
 666
 667 static struct class *vmlogrdr_class;
 668 static struct device_driver vmlogrdr_driver = {
 669         .name = "vmlogrdr",
 670         .bus  = &iucv_bus,
 671 };
 672
 673
 674 static int vmlogrdr_register_driver(void)
 675 {
 676         int ret;
 677
 678         /* Register with iucv driver */
 679         ret = iucv_register(&vmlogrdr_iucv_handler, 1);
 680         if (ret)
 681                 goto out;
 682
 683         ret = driver_register(&vmlogrdr_driver);
 684         if (ret)
 685                 goto out_iucv;
 686
 687         ret = driver_create_file(&vmlogrdr_driver,
 688                                  &driver_attr_recording_status);
 689         if (ret)
 690                 goto out_driver;
 691
 692         vmlogrdr_class = class_create(THIS_MODULE, "vmlogrdr");
 693         if (IS_ERR(vmlogrdr_class)) {
 694                 ret = PTR_ERR(vmlogrdr_class);
 695                 vmlogrdr_class = NULL;
 696                 goto out_attr;
 697         }
 698         return 0;
 699
 700 out_attr:
 701         driver_remove_file(&vmlogrdr_driver, &driver_attr_recording_status);
 702 out_driver:
 703         driver_unregister(&vmlogrdr_driver);
 704 out_iucv:
 705         iucv_unregister(&vmlogrdr_iucv_handler, 1);
 706 out:
 707         return ret;
 708 }
 709
 710
 711 static void vmlogrdr_unregister_driver(void)
 712 {
 713         class_destroy(vmlogrdr_class);
 714         vmlogrdr_class = NULL;
 715         driver_remove_file(&vmlogrdr_driver, &driver_attr_recording_status);
 716         driver_unregister(&vmlogrdr_driver);
 717         iucv_unregister(&vmlogrdr_iucv_handler, 1);
 718 }
 719
 720
 721 static int vmlogrdr_register_device(struct vmlogrdr_priv_t *priv)
 722 {
 723         struct device *dev;
 724         int ret;
 725
 726         dev = kzalloc(sizeof(struct device), GFP_KERNEL);
 727         if (dev) {
 728                 dev_set_name(dev, priv->internal_name);
 729                 dev->bus = &iucv_bus;
 730                 dev->parent = iucv_root;
 731                 dev->driver = &vmlogrdr_driver;
 732                 /*
 733                  * The release function could be called after the
 734                  * module has been unloaded. It's _only_ task is to
 735                  * free the struct. Therefore, we specify kfree()
 736                  * directly here. (Probably a little bit obfuscating
 737                  * but legitime ...).
 738                  */
 739                 dev->release = (void (*)(struct device *))kfree;
 740         } else
 741                 return -ENOMEM;
 742         ret = device_register(dev);
 743         if (ret)
 744                 return ret;
 745
 746         ret = sysfs_create_group(&dev->kobj, &vmlogrdr_attr_group);
 747         if (ret) {
 748                 device_unregister(dev);
 749                 return ret;
 750         }
 751         priv->class_device = device_create(vmlogrdr_class, dev,
 752                                            MKDEV(vmlogrdr_major,
 753                                                  priv->minor_num),
 754                                            priv, "%s", dev_name(dev));
 755         if (IS_ERR(priv->class_device)) {
 756                 ret = PTR_ERR(priv->class_device);
 757                 priv->class_device=NULL;
 758                 sysfs_remove_group(&dev->kobj, &vmlogrdr_attr_group);
 759                 device_unregister(dev);
 760                 return ret;
 761         }
 762         priv->device = dev;
 763         return 0;
 764 }
 765
 766
 767 static int vmlogrdr_unregister_device(struct vmlogrdr_priv_t *priv)
 768 {
 769         device_destroy(vmlogrdr_class, MKDEV(vmlogrdr_major, priv->minor_num));
 770         if (priv->device != NULL) {
 771                 sysfs_remove_group(&priv->device->kobj, &vmlogrdr_attr_group);
 772                 device_unregister(priv->device);
 773                 priv->device=NULL;
 774         }
 775         return 0;
 776 }
 777
 778
 779 static int vmlogrdr_register_cdev(dev_t dev)
 780 {
 781         int rc = 0;
 782         vmlogrdr_cdev = cdev_alloc();
 783         if (!vmlogrdr_cdev) {
 784                 return -ENOMEM;
 785         }
 786         vmlogrdr_cdev->owner = THIS_MODULE;
 787         vmlogrdr_cdev->ops = &vmlogrdr_fops;
 788         vmlogrdr_cdev->dev = dev;
 789         rc = cdev_add(vmlogrdr_cdev, vmlogrdr_cdev->dev, MAXMINOR);
 790         if (!rc)
 791                 return 0;
 792
 793         // cleanup: cdev is not fully registered, no cdev_del here!
 794         kobject_put(&vmlogrdr_cdev->kobj);
 795         vmlogrdr_cdev=NULL;
 796         return rc;
 797 }
 798
 799
 800 static void vmlogrdr_cleanup(void)
 801 {
 802         int i;
 803
 804         if (vmlogrdr_cdev) {
 805                 cdev_del(vmlogrdr_cdev);
 806                 vmlogrdr_cdev=NULL;
 807         }
 808         for (i=0; i < MAXMINOR; ++i ) {
 809                 vmlogrdr_unregister_device(&sys_ser[i]);
 810                 free_page((unsigned long)sys_ser[i].buffer);
 811         }
 812         vmlogrdr_unregister_driver();
 813         if (vmlogrdr_major) {
 814                 unregister_chrdev_region(MKDEV(vmlogrdr_major, 0), MAXMINOR);
 815                 vmlogrdr_major=0;
 816         }
 817 }
 818
 819
 820 static int __init vmlogrdr_init(void)
 821 {
 822         int rc;
 823         int i;
 824         dev_t dev;
 825
 826         if (! MACHINE_IS_VM) {
 827                 pr_err("not running under VM, driver not loaded.\n");
 828                 return -ENODEV;
 829         }
 830
 831         recording_class_AB = vmlogrdr_get_recording_class_AB();
 832
 833         rc = alloc_chrdev_region(&dev, 0, MAXMINOR, "vmlogrdr");
 834         if (rc)
 835                 return rc;
 836         vmlogrdr_major = MAJOR(dev);
 837
 838         rc=vmlogrdr_register_driver();
 839         if (rc)
 840                 goto cleanup;
 841
 842         for (i=0; i < MAXMINOR; ++i ) {
 843                 sys_ser[i].buffer = (char *) get_zeroed_page(GFP_KERNEL);
 844                 if (!sys_ser[i].buffer) {
 845                         rc = -ENOMEM;
 846                         break;
 847                 }
 848                 sys_ser[i].current_position = sys_ser[i].buffer;
 849                 rc=vmlogrdr_register_device(&sys_ser[i]);
 850                 if (rc)
 851                         break;
 852         }
 853         if (rc)
 854                 goto cleanup;
 855
 856         rc = vmlogrdr_register_cdev(dev);
 857         if (rc)
 858                 goto cleanup;
 859         return 0;
 860
 861 cleanup:
 862         vmlogrdr_cleanup();
 863         return rc;
 864 }
 865
 866
 867 static void __exit vmlogrdr_exit(void)
 868 {
 869         vmlogrdr_cleanup();
 870         return;
 871 }
 872
 873
 874 module_init(vmlogrdr_init);
 875 module_exit(vmlogrdr_exit);