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                                  unsigned long *data);
  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                 PRINT_WARN("Invalid value, must be 0 or 1\n");
 172                 return -EINVAL;
 173         }
 174         down_write(&dcssblk_devices_sem);
 175         dev_info = container_of(dev, struct dcssblk_dev_info, dev);
 176         if (atomic_read(&dev_info->use_count)) {
 177                 PRINT_ERR("share: segment %s is busy!\n",
 178                           dev_info->segment_name);
 179                 rc = -EBUSY;
 180                 goto out;
 181         }
 182         if (inbuf[0] == '1') {
 183                 // reload segment in shared mode
 184                 rc = segment_modify_shared(dev_info->segment_name,
 185                                            SEGMENT_SHARED);
 186                 if (rc < 0) {
 187                         BUG_ON(rc == -EINVAL);
 188                         if (rc != -EAGAIN)
 189                                 goto removeseg;
 190                 } else {
 191                         dev_info->is_shared = 1;
 192                         switch (dev_info->segment_type) {
 193                                 case SEG_TYPE_SR:
 194                                 case SEG_TYPE_ER:
 195                                 case SEG_TYPE_SC:
 196                                         set_disk_ro(dev_info->gd,1);
 197                         }
 198                 }
 199         } else if (inbuf[0] == '0') {
 200                 // reload segment in exclusive mode
 201                 if (dev_info->segment_type == SEG_TYPE_SC) {
 202                         PRINT_ERR("Segment type SC (%s) cannot be loaded in "
 203                                   "non-shared mode\n", dev_info->segment_name);
 204                         rc = -EINVAL;
 205                         goto out;
 206                 }
 207                 rc = segment_modify_shared(dev_info->segment_name,
 208                                            SEGMENT_EXCLUSIVE);
 209                 if (rc < 0) {
 210                         BUG_ON(rc == -EINVAL);
 211                         if (rc != -EAGAIN)
 212                                 goto removeseg;
 213                 } else {
 214                         dev_info->is_shared = 0;
 215                         set_disk_ro(dev_info->gd, 0);
 216                 }
 217         } else {
 218                 PRINT_WARN("Invalid value, must be 0 or 1\n");
 219                 rc = -EINVAL;
 220                 goto out;
 221         }
 222         rc = count;
 223         goto out;
 224
 225 removeseg:
 226         PRINT_ERR("Could not reload segment %s, removing it now!\n",
 227                         dev_info->segment_name);
 228         list_del(&dev_info->lh);
 229
 230         del_gendisk(dev_info->gd);
 231         blk_cleanup_queue(dev_info->dcssblk_queue);
 232         dev_info->gd->queue = NULL;
 233         put_disk(dev_info->gd);
 234         rc = device_schedule_callback(dev, dcssblk_unregister_callback);
 235 out:
 236         up_write(&dcssblk_devices_sem);
 237         return rc;
 238 }
 239
 240 /*
 241  * device attribute for save operation on current copy
 242  * of the segment. If the segment is busy, saving will
 243  * become pending until it gets released, which can be
 244  * undone by storing a non-true value to this entry.
 245  * (show + store)
 246  */
 247 static ssize_t
 248 dcssblk_save_show(struct device *dev, struct device_attribute *attr, char *buf)
 249 {
 250         struct dcssblk_dev_info *dev_info;
 251
 252         dev_info = container_of(dev, struct dcssblk_dev_info, dev);
 253         return sprintf(buf, dev_info->save_pending ? "1\n" : "0\n");
 254 }
 255
 256 static ssize_t
 257 dcssblk_save_store(struct device *dev, struct device_attribute *attr, const char *inbuf, size_t count)
 258 {
 259         struct dcssblk_dev_info *dev_info;
 260
 261         if ((count > 1) && (inbuf[1] != '\n') && (inbuf[1] != '\0')) {
 262                 PRINT_WARN("Invalid value, must be 0 or 1\n");
 263                 return -EINVAL;
 264         }
 265         dev_info = container_of(dev, struct dcssblk_dev_info, dev);
 266
 267         down_write(&dcssblk_devices_sem);
 268         if (inbuf[0] == '1') {
 269                 if (atomic_read(&dev_info->use_count) == 0) {
 270                         // device is idle => we save immediately
 271                         PRINT_INFO("Saving segment %s\n",
 272                                    dev_info->segment_name);
 273                         segment_save(dev_info->segment_name);
 274                 }  else {
 275                         // device is busy => we save it when it becomes
 276                         // idle in dcssblk_release
 277                         PRINT_INFO("Segment %s is currently busy, it will "
 278                                    "be saved when it becomes idle...\n",
 279                                    dev_info->segment_name);
 280                         dev_info->save_pending = 1;
 281                 }
 282         } else if (inbuf[0] == '0') {
 283                 if (dev_info->save_pending) {
 284                         // device is busy & the user wants to undo his save
 285                         // request
 286                         dev_info->save_pending = 0;
 287                         PRINT_INFO("Pending save for segment %s deactivated\n",
 288                                         dev_info->segment_name);
 289                 }
 290         } else {
 291                 up_write(&dcssblk_devices_sem);
 292                 PRINT_WARN("Invalid value, must be 0 or 1\n");
 293                 return -EINVAL;
 294         }
 295         up_write(&dcssblk_devices_sem);
 296         return count;
 297 }
 298
 299 /*
 300  * device attribute for adding devices
 301  */
 302 static ssize_t
 303 dcssblk_add_store(struct device *dev, struct device_attribute *attr, const char *buf, size_t count)
 304 {
 305         int rc, i;
 306         struct dcssblk_dev_info *dev_info;
 307         char *local_buf;
 308         unsigned long seg_byte_size;
 309
 310         dev_info = NULL;
 311         if (dev != dcssblk_root_dev) {
 312                 rc = -EINVAL;
 313                 goto out_nobuf;
 314         }
 315         local_buf = kmalloc(count + 1, GFP_KERNEL);
 316         if (local_buf == NULL) {
 317                 rc = -ENOMEM;
 318                 goto out_nobuf;
 319         }
 320         /*
 321          * parse input
 322          */
 323         for (i = 0; ((buf[i] != '\0') && (buf[i] != '\n') && i < count); i++) {
 324                 local_buf[i] = toupper(buf[i]);
 325         }
 326         local_buf[i] = '\0';
 327         if ((i == 0) || (i > 8)) {
 328                 rc = -ENAMETOOLONG;
 329                 goto out;
 330         }
 331         /*
 332          * already loaded?
 333          */
 334         down_read(&dcssblk_devices_sem);
 335         dev_info = dcssblk_get_device_by_name(local_buf);
 336         up_read(&dcssblk_devices_sem);
 337         if (dev_info != NULL) {
 338                 PRINT_WARN("Segment %s already loaded!\n", local_buf);
 339                 rc = -EEXIST;
 340                 goto out;
 341         }
 342         /*
 343          * get a struct dcssblk_dev_info
 344          */
 345         dev_info = kzalloc(sizeof(struct dcssblk_dev_info), GFP_KERNEL);
 346         if (dev_info == NULL) {
 347                 rc = -ENOMEM;
 348                 goto out;
 349         }
 350
 351         strcpy(dev_info->segment_name, local_buf);
 352         strlcpy(dev_info->dev.bus_id, local_buf, BUS_ID_SIZE);
 353         dev_info->dev.release = dcssblk_release_segment;
 354         INIT_LIST_HEAD(&dev_info->lh);
 355
 356         dev_info->gd = alloc_disk(DCSSBLK_MINORS_PER_DISK);
 357         if (dev_info->gd == NULL) {
 358                 rc = -ENOMEM;
 359                 goto free_dev_info;
 360         }
 361         dev_info->gd->major = dcssblk_major;
 362         dev_info->gd->fops = &dcssblk_devops;
 363         dev_info->dcssblk_queue = blk_alloc_queue(GFP_KERNEL);
 364         dev_info->gd->queue = dev_info->dcssblk_queue;
 365         dev_info->gd->private_data = dev_info;
 366         dev_info->gd->driverfs_dev = &dev_info->dev;
 367         blk_queue_make_request(dev_info->dcssblk_queue, dcssblk_make_request);
 368         blk_queue_hardsect_size(dev_info->dcssblk_queue, 4096);
 369         /*
 370          * load the segment
 371          */
 372         rc = segment_load(local_buf, SEGMENT_SHARED,
 373                                 &dev_info->start, &dev_info->end);
 374         if (rc < 0) {
 375                 segment_warning(rc, dev_info->segment_name);
 376                 goto dealloc_gendisk;
 377         }
 378         seg_byte_size = (dev_info->end - dev_info->start + 1);
 379         set_capacity(dev_info->gd, seg_byte_size >> 9); // size in sectors
 380         PRINT_INFO("Loaded segment %s, size = %lu Byte, "
 381                    "capacity = %lu (512 Byte) sectors\n", local_buf,
 382                    seg_byte_size, seg_byte_size >> 9);
 383
 384         dev_info->segment_type = rc;
 385         dev_info->save_pending = 0;
 386         dev_info->is_shared = 1;
 387         dev_info->dev.parent = dcssblk_root_dev;
 388
 389         /*
 390          * get minor, add to list
 391          */
 392         down_write(&dcssblk_devices_sem);
 393         rc = dcssblk_assign_free_minor(dev_info);
 394         if (rc) {
 395                 up_write(&dcssblk_devices_sem);
 396                 PRINT_ERR("No free minor number available! "
 397                           "Unloading segment...\n");
 398                 goto unload_seg;
 399         }
 400         sprintf(dev_info->gd->disk_name, "dcssblk%d",
 401                 dev_info->gd->first_minor);
 402         list_add_tail(&dev_info->lh, &dcssblk_devices);
 403
 404         if (!try_module_get(THIS_MODULE)) {
 405                 rc = -ENODEV;
 406                 goto list_del;
 407         }
 408         /*
 409          * register the device
 410          */
 411         rc = device_register(&dev_info->dev);
 412         if (rc) {
 413                 PRINT_ERR("Segment %s could not be registered RC=%d\n",
 414                                 local_buf, rc);
 415                 module_put(THIS_MODULE);
 416                 goto list_del;
 417         }
 418         get_device(&dev_info->dev);
 419         rc = device_create_file(&dev_info->dev, &dev_attr_shared);
 420         if (rc)
 421                 goto unregister_dev;
 422         rc = device_create_file(&dev_info->dev, &dev_attr_save);
 423         if (rc)
 424                 goto unregister_dev;
 425
 426         add_disk(dev_info->gd);
 427
 428         switch (dev_info->segment_type) {
 429                 case SEG_TYPE_SR:
 430                 case SEG_TYPE_ER:
 431                 case SEG_TYPE_SC:
 432                         set_disk_ro(dev_info->gd,1);
 433                         break;
 434                 default:
 435                         set_disk_ro(dev_info->gd,0);
 436                         break;
 437         }
 438         PRINT_DEBUG("Segment %s loaded successfully\n", local_buf);
 439         up_write(&dcssblk_devices_sem);
 440         rc = count;
 441         goto out;
 442
 443 unregister_dev:
 444         PRINT_ERR("device_create_file() failed!\n");
 445         list_del(&dev_info->lh);
 446         blk_cleanup_queue(dev_info->dcssblk_queue);
 447         dev_info->gd->queue = NULL;
 448         put_disk(dev_info->gd);
 449         device_unregister(&dev_info->dev);
 450         segment_unload(dev_info->segment_name);
 451         put_device(&dev_info->dev);
 452         up_write(&dcssblk_devices_sem);
 453         goto out;
 454 list_del:
 455         list_del(&dev_info->lh);
 456         up_write(&dcssblk_devices_sem);
 457 unload_seg:
 458         segment_unload(local_buf);
 459 dealloc_gendisk:
 460         blk_cleanup_queue(dev_info->dcssblk_queue);
 461         dev_info->gd->queue = NULL;
 462         put_disk(dev_info->gd);
 463 free_dev_info:
 464         kfree(dev_info);
 465 out:
 466         kfree(local_buf);
 467 out_nobuf:
 468         return rc;
 469 }
 470
 471 /*
 472  * device attribute for removing devices
 473  */
 474 static ssize_t
 475 dcssblk_remove_store(struct device *dev, struct device_attribute *attr, const char *buf, size_t count)
 476 {
 477         struct dcssblk_dev_info *dev_info;
 478         int rc, i;
 479         char *local_buf;
 480
 481         if (dev != dcssblk_root_dev) {
 482                 return -EINVAL;
 483         }
 484         local_buf = kmalloc(count + 1, GFP_KERNEL);
 485         if (local_buf == NULL) {
 486                 return -ENOMEM;
 487         }
 488         /*
 489          * parse input
 490          */
 491         for (i = 0; ((*(buf+i)!='\0') && (*(buf+i)!='\n') && i < count); i++) {
 492                 local_buf[i] = toupper(buf[i]);
 493         }
 494         local_buf[i] = '\0';
 495         if ((i == 0) || (i > 8)) {
 496                 rc = -ENAMETOOLONG;
 497                 goto out_buf;
 498         }
 499
 500         down_write(&dcssblk_devices_sem);
 501         dev_info = dcssblk_get_device_by_name(local_buf);
 502         if (dev_info == NULL) {
 503                 up_write(&dcssblk_devices_sem);
 504                 PRINT_WARN("Segment %s is not loaded!\n", local_buf);
 505                 rc = -ENODEV;
 506                 goto out_buf;
 507         }
 508         if (atomic_read(&dev_info->use_count) != 0) {
 509                 up_write(&dcssblk_devices_sem);
 510                 PRINT_WARN("Segment %s is in use!\n", local_buf);
 511                 rc = -EBUSY;
 512                 goto out_buf;
 513         }
 514         list_del(&dev_info->lh);
 515
 516         del_gendisk(dev_info->gd);
 517         blk_cleanup_queue(dev_info->dcssblk_queue);
 518         dev_info->gd->queue = NULL;
 519         put_disk(dev_info->gd);
 520         device_unregister(&dev_info->dev);
 521         segment_unload(dev_info->segment_name);
 522         PRINT_DEBUG("Segment %s unloaded successfully\n",
 523                         dev_info->segment_name);
 524         put_device(&dev_info->dev);
 525         up_write(&dcssblk_devices_sem);
 526
 527         rc = count;
 528 out_buf:
 529         kfree(local_buf);
 530         return rc;
 531 }
 532
 533 static int
 534 dcssblk_open(struct inode *inode, struct file *filp)
 535 {
 536         struct dcssblk_dev_info *dev_info;
 537         int rc;
 538
 539         dev_info = inode->i_bdev->bd_disk->private_data;
 540         if (NULL == dev_info) {
 541                 rc = -ENODEV;
 542                 goto out;
 543         }
 544         atomic_inc(&dev_info->use_count);
 545         inode->i_bdev->bd_block_size = 4096;
 546         rc = 0;
 547 out:
 548         return rc;
 549 }
 550
 551 static int
 552 dcssblk_release(struct inode *inode, struct file *filp)
 553 {
 554         struct dcssblk_dev_info *dev_info;
 555         int rc;
 556
 557         dev_info = inode->i_bdev->bd_disk->private_data;
 558         if (NULL == dev_info) {
 559                 rc = -ENODEV;
 560                 goto out;
 561         }
 562         down_write(&dcssblk_devices_sem);
 563         if (atomic_dec_and_test(&dev_info->use_count)
 564             && (dev_info->save_pending)) {
 565                 PRINT_INFO("Segment %s became idle and is being saved now\n",
 566                             dev_info->segment_name);
 567                 segment_save(dev_info->segment_name);
 568                 dev_info->save_pending = 0;
 569         }
 570         up_write(&dcssblk_devices_sem);
 571         rc = 0;
 572 out:
 573         return rc;
 574 }
 575
 576 static int
 577 dcssblk_make_request(struct request_queue *q, struct bio *bio)
 578 {
 579         struct dcssblk_dev_info *dev_info;
 580         struct bio_vec *bvec;
 581         unsigned long index;
 582         unsigned long page_addr;
 583         unsigned long source_addr;
 584         unsigned long bytes_done;
 585         int i;
 586
 587         bytes_done = 0;
 588         dev_info = bio->bi_bdev->bd_disk->private_data;
 589         if (dev_info == NULL)
 590                 goto fail;
 591         if ((bio->bi_sector & 7) != 0 || (bio->bi_size & 4095) != 0)
 592                 /* Request is not page-aligned. */
 593                 goto fail;
 594         if (((bio->bi_size >> 9) + bio->bi_sector)
 595                         > get_capacity(bio->bi_bdev->bd_disk)) {
 596                 /* Request beyond end of DCSS segment. */
 597                 goto fail;
 598         }
 599         /* verify data transfer direction */
 600         if (dev_info->is_shared) {
 601                 switch (dev_info->segment_type) {
 602                 case SEG_TYPE_SR:
 603                 case SEG_TYPE_ER:
 604                 case SEG_TYPE_SC:
 605                         /* cannot write to these segments */
 606                         if (bio_data_dir(bio) == WRITE) {
 607                                 PRINT_WARN("rejecting write to ro segment %s\n", dev_info->dev.bus_id);
 608                                 goto fail;
 609                         }
 610                 }
 611         }
 612
 613         index = (bio->bi_sector >> 3);
 614         bio_for_each_segment(bvec, bio, i) {
 615                 page_addr = (unsigned long)
 616                         page_address(bvec->bv_page) + bvec->bv_offset;
 617                 source_addr = dev_info->start + (index<<12) + bytes_done;
 618                 if (unlikely((page_addr & 4095) != 0) || (bvec->bv_len & 4095) != 0)
 619                         // More paranoia.
 620                         goto fail;
 621                 if (bio_data_dir(bio) == READ) {
 622                         memcpy((void*)page_addr, (void*)source_addr,
 623                                 bvec->bv_len);
 624                 } else {
 625                         memcpy((void*)source_addr, (void*)page_addr,
 626                                 bvec->bv_len);
 627                 }
 628                 bytes_done += bvec->bv_len;
 629         }
 630         bio_endio(bio, 0);
 631         return 0;
 632 fail:
 633         bio_io_error(bio);
 634         return 0;
 635 }
 636
 637 static int
 638 dcssblk_direct_access (struct block_device *bdev, sector_t secnum,
 639                         unsigned long *data)
 640 {
 641         struct dcssblk_dev_info *dev_info;
 642         unsigned long pgoff;
 643
 644         dev_info = bdev->bd_disk->private_data;
 645         if (!dev_info)
 646                 return -ENODEV;
 647         if (secnum % (PAGE_SIZE/512))
 648                 return -EINVAL;
 649         pgoff = secnum / (PAGE_SIZE / 512);
 650         if ((pgoff+1)*PAGE_SIZE-1 > dev_info->end - dev_info->start)
 651                 return -ERANGE;
 652         *data = (unsigned long) (dev_info->start+pgoff*PAGE_SIZE);
 653         return 0;
 654 }
 655
 656 static void
 657 dcssblk_check_params(void)
 658 {
 659         int rc, i, j, k;
 660         char buf[9];
 661         struct dcssblk_dev_info *dev_info;
 662
 663         for (i = 0; (i < DCSSBLK_PARM_LEN) && (dcssblk_segments[i] != '\0');
 664              i++) {
 665                 for (j = i; (dcssblk_segments[j] != ',')  &&
 666                             (dcssblk_segments[j] != '\0') &&
 667                             (dcssblk_segments[j] != '(')  &&
 668                             (j - i) < 8; j++)
 669                 {
 670                         buf[j-i] = dcssblk_segments[j];
 671                 }
 672                 buf[j-i] = '\0';
 673                 rc = dcssblk_add_store(dcssblk_root_dev, NULL, buf, j-i);
 674                 if ((rc >= 0) && (dcssblk_segments[j] == '(')) {
 675                         for (k = 0; buf[k] != '\0'; k++)
 676                                 buf[k] = toupper(buf[k]);
 677                         if (!strncmp(&dcssblk_segments[j], "(local)", 7)) {
 678                                 down_read(&dcssblk_devices_sem);
 679                                 dev_info = dcssblk_get_device_by_name(buf);
 680                                 up_read(&dcssblk_devices_sem);
 681                                 if (dev_info)
 682                                         dcssblk_shared_store(&dev_info->dev,
 683                                                              NULL, "0\n", 2);
 684                         }
 685                 }
 686                 while ((dcssblk_segments[j] != ',') &&
 687                        (dcssblk_segments[j] != '\0'))
 688                 {
 689                         j++;
 690                 }
 691                 if (dcssblk_segments[j] == '\0')
 692                         break;
 693                 i = j;
 694         }
 695 }
 696
 697 /*
 698  * The init/exit functions.
 699  */
 700 static void __exit
 701 dcssblk_exit(void)
 702 {
 703         PRINT_DEBUG("DCSSBLOCK EXIT...\n");
 704         s390_root_dev_unregister(dcssblk_root_dev);
 705         unregister_blkdev(dcssblk_major, DCSSBLK_NAME);
 706         PRINT_DEBUG("...finished!\n");
 707 }
 708
 709 static int __init
 710 dcssblk_init(void)
 711 {
 712         int rc;
 713
 714         PRINT_DEBUG("DCSSBLOCK INIT...\n");
 715         dcssblk_root_dev = s390_root_dev_register("dcssblk");
 716         if (IS_ERR(dcssblk_root_dev)) {
 717                 PRINT_ERR("device_register() failed!\n");
 718                 return PTR_ERR(dcssblk_root_dev);
 719         }
 720         rc = device_create_file(dcssblk_root_dev, &dev_attr_add);
 721         if (rc) {
 722                 PRINT_ERR("device_create_file(add) failed!\n");
 723                 s390_root_dev_unregister(dcssblk_root_dev);
 724                 return rc;
 725         }
 726         rc = device_create_file(dcssblk_root_dev, &dev_attr_remove);
 727         if (rc) {
 728                 PRINT_ERR("device_create_file(remove) failed!\n");
 729                 s390_root_dev_unregister(dcssblk_root_dev);
 730                 return rc;
 731         }
 732         rc = register_blkdev(0, DCSSBLK_NAME);
 733         if (rc < 0) {
 734                 PRINT_ERR("Can't get dynamic major!\n");
 735                 s390_root_dev_unregister(dcssblk_root_dev);
 736                 return rc;
 737         }
 738         dcssblk_major = rc;
 739         init_rwsem(&dcssblk_devices_sem);
 740
 741         dcssblk_check_params();
 742
 743         PRINT_DEBUG("...finished!\n");
 744         return 0;
 745 }
 746
 747 module_init(dcssblk_init);
 748 module_exit(dcssblk_exit);
 749
 750 module_param_string(segments, dcssblk_segments, DCSSBLK_PARM_LEN, 0444);
 751 MODULE_PARM_DESC(segments, "Name of DCSS segment(s) to be loaded, "
 752                  "comma-separated list, each name max. 8 chars.\n"
 753                  "Adding \"(local)\" to segment name equals echoing 0 to "
 754                  "/sys/devices/dcssblk/<segment name>/shared after loading "
 755                  "the segment - \n"
 756                  "e.g. segments=\"mydcss1,mydcss2,mydcss3(local)\"");
 757
 758 MODULE_LICENSE("GPL");