git.oblomov.eu Git - linux-2.6/blob - drivers/s390/block/dcssblk.c

   1 /*
   2  * dcssblk.c -- the S/390 block driver for dcss memory
   3  *
   4  * Authors: Carsten Otte, Stefan Weinhuber, Gerald Schaefer
   5  */
   6
   7 #include <linux/module.h>
   8 #include <linux/moduleparam.h>
   9 #include <linux/ctype.h>
  10 #include <linux/errno.h>
  11 #include <linux/init.h>
  12 #include <linux/slab.h>
  13 #include <linux/blkdev.h>
  14 #include <asm/extmem.h>
  15 #include <asm/io.h>
  16 #include <linux/completion.h>
  17 #include <linux/interrupt.h>
  18 #include <asm/s390_rdev.h>
  19
  20 //#define DCSSBLK_DEBUG         /* Debug messages on/off */
  21 #define DCSSBLK_NAME "dcssblk"
  22 #define DCSSBLK_MINORS_PER_DISK 1
  23 #define DCSSBLK_PARM_LEN 400
  24
  25 #ifdef DCSSBLK_DEBUG
  26 #define PRINT_DEBUG(x...) printk(KERN_DEBUG DCSSBLK_NAME " debug: " x)
  27 #else
  28 #define PRINT_DEBUG(x...) do {} while (0)
  29 #endif
  30 #define PRINT_INFO(x...)  printk(KERN_INFO DCSSBLK_NAME " info: " x)
  31 #define PRINT_WARN(x...)  printk(KERN_WARNING DCSSBLK_NAME " warning: " x)
  32 #define PRINT_ERR(x...)   printk(KERN_ERR DCSSBLK_NAME " error: " x)
  33
  34
  35 static int dcssblk_open(struct inode *inode, struct file *filp);
  36 static int dcssblk_release(struct inode *inode, struct file *filp);
  37 static int dcssblk_make_request(struct request_queue *q, struct bio *bio);
  38 static int dcssblk_direct_access(struct block_device *bdev, sector_t secnum,
  39                                  void **kaddr, unsigned long *pfn);
  40
  41 static char dcssblk_segments[DCSSBLK_PARM_LEN] = "\0";
  42
  43 static int dcssblk_major;
  44 static struct block_device_operations dcssblk_devops = {
  45         .owner          = THIS_MODULE,
  46         .open           = dcssblk_open,
  47         .release        = dcssblk_release,
  48         .direct_access  = dcssblk_direct_access,
  49 };
  50
  51 static ssize_t dcssblk_add_store(struct device * dev, struct device_attribute *attr, const char * buf,
  52                                   size_t count);
  53 static ssize_t dcssblk_remove_store(struct device * dev, struct device_attribute *attr, const char * buf,
  54                                   size_t count);
  55 static ssize_t dcssblk_save_store(struct device * dev, struct device_attribute *attr, const char * buf,
  56                                   size_t count);
  57 static ssize_t dcssblk_save_show(struct device *dev, struct device_attribute *attr, char *buf);
  58 static ssize_t dcssblk_shared_store(struct device * dev, struct device_attribute *attr, const char * buf,
  59                                   size_t count);
  60 static ssize_t dcssblk_shared_show(struct device *dev, struct device_attribute *attr, char *buf);
  61
  62 static DEVICE_ATTR(add, S_IWUSR, NULL, dcssblk_add_store);
  63 static DEVICE_ATTR(remove, S_IWUSR, NULL, dcssblk_remove_store);
  64 static DEVICE_ATTR(save, S_IWUSR | S_IRUGO, dcssblk_save_show,
  65                    dcssblk_save_store);
  66 static DEVICE_ATTR(shared, S_IWUSR | S_IRUGO, dcssblk_shared_show,
  67                    dcssblk_shared_store);
  68
  69 static struct device *dcssblk_root_dev;
  70
  71 struct dcssblk_dev_info {
  72         struct list_head lh;
  73         struct device dev;
  74         char segment_name[BUS_ID_SIZE];
  75         atomic_t use_count;
  76         struct gendisk *gd;
  77         unsigned long start;
  78         unsigned long end;
  79         int segment_type;
  80         unsigned char save_pending;
  81         unsigned char is_shared;
  82         struct request_queue *dcssblk_queue;
  83 };
  84
  85 static LIST_HEAD(dcssblk_devices);
  86 static struct rw_semaphore dcssblk_devices_sem;
  87
  88 /*
  89  * release function for segment device.
  90  */
  91 static void
  92 dcssblk_release_segment(struct device *dev)
  93 {
  94         PRINT_DEBUG("segment release fn called for %s\n", dev->bus_id);
  95         kfree(container_of(dev, struct dcssblk_dev_info, dev));
  96         module_put(THIS_MODULE);
  97 }
  98
  99 /*
 100  * get a minor number. needs to be called with
 101  * down_write(&dcssblk_devices_sem) and the
 102  * device needs to be enqueued before the semaphore is
 103  * freed.
 104  */
 105 static int
 106 dcssblk_assign_free_minor(struct dcssblk_dev_info *dev_info)
 107 {
 108         int minor, found;
 109         struct dcssblk_dev_info *entry;
 110
 111         if (dev_info == NULL)
 112                 return -EINVAL;
 113         for (minor = 0; minor < (1<<MINORBITS); minor++) {
 114                 found = 0;
 115                 // test if minor available
 116                 list_for_each_entry(entry, &dcssblk_devices, lh)
 117                         if (minor == entry->gd->first_minor)
 118                                 found++;
 119                 if (!found) break; // got unused minor
 120         }
 121         if (found)
 122                 return -EBUSY;
 123         dev_info->gd->first_minor = minor;
 124         return 0;
 125 }
 126
 127 /*
 128  * get the struct dcssblk_dev_info from dcssblk_devices
 129  * for the given name.
 130  * down_read(&dcssblk_devices_sem) must be held.
 131  */
 132 static struct dcssblk_dev_info *
 133 dcssblk_get_device_by_name(char *name)
 134 {
 135         struct dcssblk_dev_info *entry;
 136
 137         list_for_each_entry(entry, &dcssblk_devices, lh) {
 138                 if (!strcmp(name, entry->segment_name)) {
 139                         return entry;
 140                 }
 141         }
 142         return NULL;
 143 }
 144
 145 static void dcssblk_unregister_callback(struct device *dev)
 146 {
 147         device_unregister(dev);
 148         put_device(dev);
 149 }
 150
 151 /*
 152  * device attribute for switching shared/nonshared (exclusive)
 153  * operation (show + store)
 154  */
 155 static ssize_t
 156 dcssblk_shared_show(struct device *dev, struct device_attribute *attr, char *buf)
 157 {
 158         struct dcssblk_dev_info *dev_info;
 159
 160         dev_info = container_of(dev, struct dcssblk_dev_info, dev);
 161         return sprintf(buf, dev_info->is_shared ? "1\n" : "0\n");
 162 }
 163
 164 static ssize_t
 165 dcssblk_shared_store(struct device *dev, struct device_attribute *attr, const char *inbuf, size_t count)
 166 {
 167         struct dcssblk_dev_info *dev_info;
 168         int rc;
 169
 170         if ((count > 1) && (inbuf[1] != '\n') && (inbuf[1] != '\0'))
 171                 return -EINVAL;
 172         down_write(&dcssblk_devices_sem);
 173         dev_info = container_of(dev, struct dcssblk_dev_info, dev);
 174         if (atomic_read(&dev_info->use_count)) {
 175                 PRINT_ERR("share: segment %s is busy!\n",
 176                           dev_info->segment_name);
 177                 rc = -EBUSY;
 178                 goto out;
 179         }
 180         if (inbuf[0] == '1') {
 181                 // reload segment in shared mode
 182                 rc = segment_modify_shared(dev_info->segment_name,
 183                                            SEGMENT_SHARED);
 184                 if (rc < 0) {
 185                         BUG_ON(rc == -EINVAL);
 186                         if (rc != -EAGAIN)
 187                                 goto removeseg;
 188                 } else {
 189                         dev_info->is_shared = 1;
 190                         switch (dev_info->segment_type) {
 191                                 case SEG_TYPE_SR:
 192                                 case SEG_TYPE_ER:
 193                                 case SEG_TYPE_SC:
 194                                         set_disk_ro(dev_info->gd,1);
 195                         }
 196                 }
 197         } else if (inbuf[0] == '0') {
 198                 // reload segment in exclusive mode
 199                 if (dev_info->segment_type == SEG_TYPE_SC) {
 200                         PRINT_ERR("Segment type SC (%s) cannot be loaded in "
 201                                   "non-shared mode\n", dev_info->segment_name);
 202                         rc = -EINVAL;
 203                         goto out;
 204                 }
 205                 rc = segment_modify_shared(dev_info->segment_name,
 206                                            SEGMENT_EXCLUSIVE);
 207                 if (rc < 0) {
 208                         BUG_ON(rc == -EINVAL);
 209                         if (rc != -EAGAIN)
 210                                 goto removeseg;
 211                 } else {
 212                         dev_info->is_shared = 0;
 213                         set_disk_ro(dev_info->gd, 0);
 214                 }
 215         } else {
 216                 rc = -EINVAL;
 217                 goto out;
 218         }
 219         rc = count;
 220         goto out;
 221
 222 removeseg:
 223         PRINT_ERR("Could not reload segment %s, removing it now!\n",
 224                         dev_info->segment_name);
 225         list_del(&dev_info->lh);
 226
 227         del_gendisk(dev_info->gd);
 228         blk_cleanup_queue(dev_info->dcssblk_queue);
 229         dev_info->gd->queue = NULL;
 230         put_disk(dev_info->gd);
 231         rc = device_schedule_callback(dev, dcssblk_unregister_callback);
 232 out:
 233         up_write(&dcssblk_devices_sem);
 234         return rc;
 235 }
 236
 237 /*
 238  * device attribute for save operation on current copy
 239  * of the segment. If the segment is busy, saving will
 240  * become pending until it gets released, which can be
 241  * undone by storing a non-true value to this entry.
 242  * (show + store)
 243  */
 244 static ssize_t
 245 dcssblk_save_show(struct device *dev, struct device_attribute *attr, char *buf)
 246 {
 247         struct dcssblk_dev_info *dev_info;
 248
 249         dev_info = container_of(dev, struct dcssblk_dev_info, dev);
 250         return sprintf(buf, dev_info->save_pending ? "1\n" : "0\n");
 251 }
 252
 253 static ssize_t
 254 dcssblk_save_store(struct device *dev, struct device_attribute *attr, const char *inbuf, size_t count)
 255 {
 256         struct dcssblk_dev_info *dev_info;
 257
 258         if ((count > 1) && (inbuf[1] != '\n') && (inbuf[1] != '\0'))
 259                 return -EINVAL;
 260         dev_info = container_of(dev, struct dcssblk_dev_info, dev);
 261
 262         down_write(&dcssblk_devices_sem);
 263         if (inbuf[0] == '1') {
 264                 if (atomic_read(&dev_info->use_count) == 0) {
 265                         // device is idle => we save immediately
 266                         PRINT_INFO("Saving segment %s\n",
 267                                    dev_info->segment_name);
 268                         segment_save(dev_info->segment_name);
 269                 }  else {
 270                         // device is busy => we save it when it becomes
 271                         // idle in dcssblk_release
 272                         PRINT_INFO("Segment %s is currently busy, it will "
 273                                    "be saved when it becomes idle...\n",
 274                                    dev_info->segment_name);
 275                         dev_info->save_pending = 1;
 276                 }
 277         } else if (inbuf[0] == '0') {
 278                 if (dev_info->save_pending) {
 279                         // device is busy & the user wants to undo his save
 280                         // request
 281                         dev_info->save_pending = 0;
 282                         PRINT_INFO("Pending save for segment %s deactivated\n",
 283                                         dev_info->segment_name);
 284                 }
 285         } else {
 286                 up_write(&dcssblk_devices_sem);
 287                 return -EINVAL;
 288         }
 289         up_write(&dcssblk_devices_sem);
 290         return count;
 291 }
 292
 293 /*
 294  * device attribute for adding devices
 295  */
 296 static ssize_t
 297 dcssblk_add_store(struct device *dev, struct device_attribute *attr, const char *buf, size_t count)
 298 {
 299         int rc, i;
 300         struct dcssblk_dev_info *dev_info;
 301         char *local_buf;
 302         unsigned long seg_byte_size;
 303
 304         dev_info = NULL;
 305         if (dev != dcssblk_root_dev) {
 306                 rc = -EINVAL;
 307                 goto out_nobuf;
 308         }
 309         local_buf = kmalloc(count + 1, GFP_KERNEL);
 310         if (local_buf == NULL) {
 311                 rc = -ENOMEM;
 312                 goto out_nobuf;
 313         }
 314         /*
 315          * parse input
 316          */
 317         for (i = 0; ((buf[i] != '\0') && (buf[i] != '\n') && i < count); i++) {
 318                 local_buf[i] = toupper(buf[i]);
 319         }
 320         local_buf[i] = '\0';
 321         if ((i == 0) || (i > 8)) {
 322                 rc = -ENAMETOOLONG;
 323                 goto out;
 324         }
 325         /*
 326          * already loaded?
 327          */
 328         down_read(&dcssblk_devices_sem);
 329         dev_info = dcssblk_get_device_by_name(local_buf);
 330         up_read(&dcssblk_devices_sem);
 331         if (dev_info != NULL) {
 332                 PRINT_WARN("Segment %s already loaded!\n", local_buf);
 333                 rc = -EEXIST;
 334                 goto out;
 335         }
 336         /*
 337          * get a struct dcssblk_dev_info
 338          */
 339         dev_info = kzalloc(sizeof(struct dcssblk_dev_info), GFP_KERNEL);
 340         if (dev_info == NULL) {
 341                 rc = -ENOMEM;
 342                 goto out;
 343         }
 344
 345         strcpy(dev_info->segment_name, local_buf);
 346         strlcpy(dev_info->dev.bus_id, local_buf, BUS_ID_SIZE);
 347         dev_info->dev.release = dcssblk_release_segment;
 348         INIT_LIST_HEAD(&dev_info->lh);
 349
 350         dev_info->gd = alloc_disk(DCSSBLK_MINORS_PER_DISK);
 351         if (dev_info->gd == NULL) {
 352                 rc = -ENOMEM;
 353                 goto free_dev_info;
 354         }
 355         dev_info->gd->major = dcssblk_major;
 356         dev_info->gd->fops = &dcssblk_devops;
 357         dev_info->dcssblk_queue = blk_alloc_queue(GFP_KERNEL);
 358         dev_info->gd->queue = dev_info->dcssblk_queue;
 359         dev_info->gd->private_data = dev_info;
 360         dev_info->gd->driverfs_dev = &dev_info->dev;
 361         blk_queue_make_request(dev_info->dcssblk_queue, dcssblk_make_request);
 362         blk_queue_hardsect_size(dev_info->dcssblk_queue, 4096);
 363         /*
 364          * load the segment
 365          */
 366         rc = segment_load(local_buf, SEGMENT_SHARED,
 367                                 &dev_info->start, &dev_info->end);
 368         if (rc < 0) {
 369                 segment_warning(rc, dev_info->segment_name);
 370                 goto dealloc_gendisk;
 371         }
 372         seg_byte_size = (dev_info->end - dev_info->start + 1);
 373         set_capacity(dev_info->gd, seg_byte_size >> 9); // size in sectors
 374         PRINT_INFO("Loaded segment %s, size = %lu Byte, "
 375                    "capacity = %lu (512 Byte) sectors\n", local_buf,
 376                    seg_byte_size, seg_byte_size >> 9);
 377
 378         dev_info->segment_type = rc;
 379         dev_info->save_pending = 0;
 380         dev_info->is_shared = 1;
 381         dev_info->dev.parent = dcssblk_root_dev;
 382
 383         /*
 384          * get minor, add to list
 385          */
 386         down_write(&dcssblk_devices_sem);
 387         rc = dcssblk_assign_free_minor(dev_info);
 388         if (rc) {
 389                 up_write(&dcssblk_devices_sem);
 390                 PRINT_ERR("No free minor number available! "
 391                           "Unloading segment...\n");
 392                 goto unload_seg;
 393         }
 394         sprintf(dev_info->gd->disk_name, "dcssblk%d",
 395                 dev_info->gd->first_minor);
 396         list_add_tail(&dev_info->lh, &dcssblk_devices);
 397
 398         if (!try_module_get(THIS_MODULE)) {
 399                 rc = -ENODEV;
 400                 goto list_del;
 401         }
 402         /*
 403          * register the device
 404          */
 405         rc = device_register(&dev_info->dev);
 406         if (rc) {
 407                 PRINT_ERR("Segment %s could not be registered RC=%d\n",
 408                                 local_buf, rc);
 409                 module_put(THIS_MODULE);
 410                 goto list_del;
 411         }
 412         get_device(&dev_info->dev);
 413         rc = device_create_file(&dev_info->dev, &dev_attr_shared);
 414         if (rc)
 415                 goto unregister_dev;
 416         rc = device_create_file(&dev_info->dev, &dev_attr_save);
 417         if (rc)
 418                 goto unregister_dev;
 419
 420         add_disk(dev_info->gd);
 421
 422         switch (dev_info->segment_type) {
 423                 case SEG_TYPE_SR:
 424                 case SEG_TYPE_ER:
 425                 case SEG_TYPE_SC:
 426                         set_disk_ro(dev_info->gd,1);
 427                         break;
 428                 default:
 429                         set_disk_ro(dev_info->gd,0);
 430                         break;
 431         }
 432         PRINT_DEBUG("Segment %s loaded successfully\n", local_buf);
 433         up_write(&dcssblk_devices_sem);
 434         rc = count;
 435         goto out;
 436
 437 unregister_dev:
 438         list_del(&dev_info->lh);
 439         blk_cleanup_queue(dev_info->dcssblk_queue);
 440         dev_info->gd->queue = NULL;
 441         put_disk(dev_info->gd);
 442         device_unregister(&dev_info->dev);
 443         segment_unload(dev_info->segment_name);
 444         put_device(&dev_info->dev);
 445         up_write(&dcssblk_devices_sem);
 446         goto out;
 447 list_del:
 448         list_del(&dev_info->lh);
 449         up_write(&dcssblk_devices_sem);
 450 unload_seg:
 451         segment_unload(local_buf);
 452 dealloc_gendisk:
 453         blk_cleanup_queue(dev_info->dcssblk_queue);
 454         dev_info->gd->queue = NULL;
 455         put_disk(dev_info->gd);
 456 free_dev_info:
 457         kfree(dev_info);
 458 out:
 459         kfree(local_buf);
 460 out_nobuf:
 461         return rc;
 462 }
 463
 464 /*
 465  * device attribute for removing devices
 466  */
 467 static ssize_t
 468 dcssblk_remove_store(struct device *dev, struct device_attribute *attr, const char *buf, size_t count)
 469 {
 470         struct dcssblk_dev_info *dev_info;
 471         int rc, i;
 472         char *local_buf;
 473
 474         if (dev != dcssblk_root_dev) {
 475                 return -EINVAL;
 476         }
 477         local_buf = kmalloc(count + 1, GFP_KERNEL);
 478         if (local_buf == NULL) {
 479                 return -ENOMEM;
 480         }
 481         /*
 482          * parse input
 483          */
 484         for (i = 0; ((*(buf+i)!='\0') && (*(buf+i)!='\n') && i < count); i++) {
 485                 local_buf[i] = toupper(buf[i]);
 486         }
 487         local_buf[i] = '\0';
 488         if ((i == 0) || (i > 8)) {
 489                 rc = -ENAMETOOLONG;
 490                 goto out_buf;
 491         }
 492
 493         down_write(&dcssblk_devices_sem);
 494         dev_info = dcssblk_get_device_by_name(local_buf);
 495         if (dev_info == NULL) {
 496                 up_write(&dcssblk_devices_sem);
 497                 PRINT_WARN("Segment %s is not loaded!\n", local_buf);
 498                 rc = -ENODEV;
 499                 goto out_buf;
 500         }
 501         if (atomic_read(&dev_info->use_count) != 0) {
 502                 up_write(&dcssblk_devices_sem);
 503                 PRINT_WARN("Segment %s is in use!\n", local_buf);
 504                 rc = -EBUSY;
 505                 goto out_buf;
 506         }
 507         list_del(&dev_info->lh);
 508
 509         del_gendisk(dev_info->gd);
 510         blk_cleanup_queue(dev_info->dcssblk_queue);
 511         dev_info->gd->queue = NULL;
 512         put_disk(dev_info->gd);
 513         device_unregister(&dev_info->dev);
 514         segment_unload(dev_info->segment_name);
 515         PRINT_DEBUG("Segment %s unloaded successfully\n",
 516                         dev_info->segment_name);
 517         put_device(&dev_info->dev);
 518         up_write(&dcssblk_devices_sem);
 519
 520         rc = count;
 521 out_buf:
 522         kfree(local_buf);
 523         return rc;
 524 }
 525
 526 static int
 527 dcssblk_open(struct inode *inode, struct file *filp)
 528 {
 529         struct dcssblk_dev_info *dev_info;
 530         int rc;
 531
 532         dev_info = inode->i_bdev->bd_disk->private_data;
 533         if (NULL == dev_info) {
 534                 rc = -ENODEV;
 535                 goto out;
 536         }
 537         atomic_inc(&dev_info->use_count);
 538         inode->i_bdev->bd_block_size = 4096;
 539         rc = 0;
 540 out:
 541         return rc;
 542 }
 543
 544 static int
 545 dcssblk_release(struct inode *inode, struct file *filp)
 546 {
 547         struct dcssblk_dev_info *dev_info;
 548         int rc;
 549
 550         dev_info = inode->i_bdev->bd_disk->private_data;
 551         if (NULL == dev_info) {
 552                 rc = -ENODEV;
 553                 goto out;
 554         }
 555         down_write(&dcssblk_devices_sem);
 556         if (atomic_dec_and_test(&dev_info->use_count)
 557             && (dev_info->save_pending)) {
 558                 PRINT_INFO("Segment %s became idle and is being saved now\n",
 559                             dev_info->segment_name);
 560                 segment_save(dev_info->segment_name);
 561                 dev_info->save_pending = 0;
 562         }
 563         up_write(&dcssblk_devices_sem);
 564         rc = 0;
 565 out:
 566         return rc;
 567 }
 568
 569 static int
 570 dcssblk_make_request(struct request_queue *q, struct bio *bio)
 571 {
 572         struct dcssblk_dev_info *dev_info;
 573         struct bio_vec *bvec;
 574         unsigned long index;
 575         unsigned long page_addr;
 576         unsigned long source_addr;
 577         unsigned long bytes_done;
 578         int i;
 579
 580         bytes_done = 0;
 581         dev_info = bio->bi_bdev->bd_disk->private_data;
 582         if (dev_info == NULL)
 583                 goto fail;
 584         if ((bio->bi_sector & 7) != 0 || (bio->bi_size & 4095) != 0)
 585                 /* Request is not page-aligned. */
 586                 goto fail;
 587         if (((bio->bi_size >> 9) + bio->bi_sector)
 588                         > get_capacity(bio->bi_bdev->bd_disk)) {
 589                 /* Request beyond end of DCSS segment. */
 590                 goto fail;
 591         }
 592         /* verify data transfer direction */
 593         if (dev_info->is_shared) {
 594                 switch (dev_info->segment_type) {
 595                 case SEG_TYPE_SR:
 596                 case SEG_TYPE_ER:
 597                 case SEG_TYPE_SC:
 598                         /* cannot write to these segments */
 599                         if (bio_data_dir(bio) == WRITE) {
 600                                 PRINT_WARN("rejecting write to ro segment %s\n", dev_info->dev.bus_id);
 601                                 goto fail;
 602                         }
 603                 }
 604         }
 605
 606         index = (bio->bi_sector >> 3);
 607         bio_for_each_segment(bvec, bio, i) {
 608                 page_addr = (unsigned long)
 609                         page_address(bvec->bv_page) + bvec->bv_offset;
 610                 source_addr = dev_info->start + (index<<12) + bytes_done;
 611                 if (unlikely((page_addr & 4095) != 0) || (bvec->bv_len & 4095) != 0)
 612                         // More paranoia.
 613                         goto fail;
 614                 if (bio_data_dir(bio) == READ) {
 615                         memcpy((void*)page_addr, (void*)source_addr,
 616                                 bvec->bv_len);
 617                 } else {
 618                         memcpy((void*)source_addr, (void*)page_addr,
 619                                 bvec->bv_len);
 620                 }
 621                 bytes_done += bvec->bv_len;
 622         }
 623         bio_endio(bio, 0);
 624         return 0;
 625 fail:
 626         bio_io_error(bio);
 627         return 0;
 628 }
 629
 630 static int
 631 dcssblk_direct_access (struct block_device *bdev, sector_t secnum,
 632                         void **kaddr, unsigned long *pfn)
 633 {
 634         struct dcssblk_dev_info *dev_info;
 635         unsigned long pgoff;
 636
 637         dev_info = bdev->bd_disk->private_data;
 638         if (!dev_info)
 639                 return -ENODEV;
 640         if (secnum % (PAGE_SIZE/512))
 641                 return -EINVAL;
 642         pgoff = secnum / (PAGE_SIZE / 512);
 643         if ((pgoff+1)*PAGE_SIZE-1 > dev_info->end - dev_info->start)
 644                 return -ERANGE;
 645         *kaddr = (void *) (dev_info->start+pgoff*PAGE_SIZE);
 646         *pfn = virt_to_phys(*kaddr) >> PAGE_SHIFT;
 647
 648         return 0;
 649 }
 650
 651 static void
 652 dcssblk_check_params(void)
 653 {
 654         int rc, i, j, k;
 655         char buf[9];
 656         struct dcssblk_dev_info *dev_info;
 657
 658         for (i = 0; (i < DCSSBLK_PARM_LEN) && (dcssblk_segments[i] != '\0');
 659              i++) {
 660                 for (j = i; (dcssblk_segments[j] != ',')  &&
 661                             (dcssblk_segments[j] != '\0') &&
 662                             (dcssblk_segments[j] != '(')  &&
 663                             (j - i) < 8; j++)
 664                 {
 665                         buf[j-i] = dcssblk_segments[j];
 666                 }
 667                 buf[j-i] = '\0';
 668                 rc = dcssblk_add_store(dcssblk_root_dev, NULL, buf, j-i);
 669                 if ((rc >= 0) && (dcssblk_segments[j] == '(')) {
 670                         for (k = 0; buf[k] != '\0'; k++)
 671                                 buf[k] = toupper(buf[k]);
 672                         if (!strncmp(&dcssblk_segments[j], "(local)", 7)) {
 673                                 down_read(&dcssblk_devices_sem);
 674                                 dev_info = dcssblk_get_device_by_name(buf);
 675                                 up_read(&dcssblk_devices_sem);
 676                                 if (dev_info)
 677                                         dcssblk_shared_store(&dev_info->dev,
 678                                                              NULL, "0\n", 2);
 679                         }
 680                 }
 681                 while ((dcssblk_segments[j] != ',') &&
 682                        (dcssblk_segments[j] != '\0'))
 683                 {
 684                         j++;
 685                 }
 686                 if (dcssblk_segments[j] == '\0')
 687                         break;
 688                 i = j;
 689         }
 690 }
 691
 692 /*
 693  * The init/exit functions.
 694  */
 695 static void __exit
 696 dcssblk_exit(void)
 697 {
 698         s390_root_dev_unregister(dcssblk_root_dev);
 699         unregister_blkdev(dcssblk_major, DCSSBLK_NAME);
 700 }
 701
 702 static int __init
 703 dcssblk_init(void)
 704 {
 705         int rc;
 706
 707         dcssblk_root_dev = s390_root_dev_register("dcssblk");
 708         if (IS_ERR(dcssblk_root_dev))
 709                 return PTR_ERR(dcssblk_root_dev);
 710         rc = device_create_file(dcssblk_root_dev, &dev_attr_add);
 711         if (rc) {
 712                 s390_root_dev_unregister(dcssblk_root_dev);
 713                 return rc;
 714         }
 715         rc = device_create_file(dcssblk_root_dev, &dev_attr_remove);
 716         if (rc) {
 717                 s390_root_dev_unregister(dcssblk_root_dev);
 718                 return rc;
 719         }
 720         rc = register_blkdev(0, DCSSBLK_NAME);
 721         if (rc < 0) {
 722                 s390_root_dev_unregister(dcssblk_root_dev);
 723                 return rc;
 724         }
 725         dcssblk_major = rc;
 726         init_rwsem(&dcssblk_devices_sem);
 727
 728         dcssblk_check_params();
 729
 730         return 0;
 731 }
 732
 733 module_init(dcssblk_init);
 734 module_exit(dcssblk_exit);
 735
 736 module_param_string(segments, dcssblk_segments, DCSSBLK_PARM_LEN, 0444);
 737 MODULE_PARM_DESC(segments, "Name of DCSS segment(s) to be loaded, "
 738                  "comma-separated list, each name max. 8 chars.\n"
 739                  "Adding \"(local)\" to segment name equals echoing 0 to "
 740                  "/sys/devices/dcssblk/<segment name>/shared after loading "
 741                  "the segment - \n"
 742                  "e.g. segments=\"mydcss1,mydcss2,mydcss3(local)\"");
 743
 744 MODULE_LICENSE("GPL");