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 static int dcssblk_open(struct inode *inode, struct file *filp);
  35 static int dcssblk_release(struct inode *inode, struct file *filp);
  36 static int dcssblk_make_request(struct request_queue *q, struct bio *bio);
  37 static int dcssblk_direct_access(struct block_device *bdev, sector_t secnum,
  38                                  void **kaddr, unsigned long *pfn);
  39
  40 static char dcssblk_segments[DCSSBLK_PARM_LEN] = "\0";
  41
  42 static int dcssblk_major;
  43 static struct block_device_operations dcssblk_devops = {
  44         .owner          = THIS_MODULE,
  45         .open           = dcssblk_open,
  46         .release        = dcssblk_release,
  47         .direct_access  = dcssblk_direct_access,
  48 };
  49
  50 struct dcssblk_dev_info {
  51         struct list_head lh;
  52         struct device dev;
  53         char segment_name[BUS_ID_SIZE];
  54         atomic_t use_count;
  55         struct gendisk *gd;
  56         unsigned long start;
  57         unsigned long end;
  58         int segment_type;
  59         unsigned char save_pending;
  60         unsigned char is_shared;
  61         struct request_queue *dcssblk_queue;
  62         int num_of_segments;
  63         struct list_head seg_list;
  64 };
  65
  66 struct segment_info {
  67         struct list_head lh;
  68         char segment_name[BUS_ID_SIZE];
  69         unsigned long start;
  70         unsigned long end;
  71         int segment_type;
  72 };
  73
  74 static ssize_t dcssblk_add_store(struct device * dev, struct device_attribute *attr, const char * buf,
  75                                   size_t count);
  76 static ssize_t dcssblk_remove_store(struct device * dev, struct device_attribute *attr, const char * buf,
  77                                   size_t count);
  78 static ssize_t dcssblk_save_store(struct device * dev, struct device_attribute *attr, const char * buf,
  79                                   size_t count);
  80 static ssize_t dcssblk_save_show(struct device *dev, struct device_attribute *attr, char *buf);
  81 static ssize_t dcssblk_shared_store(struct device * dev, struct device_attribute *attr, const char * buf,
  82                                   size_t count);
  83 static ssize_t dcssblk_shared_show(struct device *dev, struct device_attribute *attr, char *buf);
  84 static ssize_t dcssblk_seglist_show(struct device *dev,
  85                                 struct device_attribute *attr,
  86                                 char *buf);
  87
  88 static DEVICE_ATTR(add, S_IWUSR, NULL, dcssblk_add_store);
  89 static DEVICE_ATTR(remove, S_IWUSR, NULL, dcssblk_remove_store);
  90 static DEVICE_ATTR(save, S_IWUSR | S_IRUSR, dcssblk_save_show,
  91                    dcssblk_save_store);
  92 static DEVICE_ATTR(shared, S_IWUSR | S_IRUSR, dcssblk_shared_show,
  93                    dcssblk_shared_store);
  94 static DEVICE_ATTR(seglist, S_IRUSR, dcssblk_seglist_show, NULL);
  95
  96 static struct device *dcssblk_root_dev;
  97
  98 static LIST_HEAD(dcssblk_devices);
  99 static struct rw_semaphore dcssblk_devices_sem;
 100
 101 /*
 102  * release function for segment device.
 103  */
 104 static void
 105 dcssblk_release_segment(struct device *dev)
 106 {
 107         struct dcssblk_dev_info *dev_info;
 108         struct segment_info *entry, *temp;
 109
 110         dev_info = container_of(dev, struct dcssblk_dev_info, dev);
 111         list_for_each_entry_safe(entry, temp, &dev_info->seg_list, lh) {
 112                 list_del(&entry->lh);
 113                 kfree(entry);
 114         }
 115         kfree(dev_info);
 116         module_put(THIS_MODULE);
 117 }
 118
 119 /*
 120  * get a minor number. needs to be called with
 121  * down_write(&dcssblk_devices_sem) and the
 122  * device needs to be enqueued before the semaphore is
 123  * freed.
 124  */
 125 static int
 126 dcssblk_assign_free_minor(struct dcssblk_dev_info *dev_info)
 127 {
 128         int minor, found;
 129         struct dcssblk_dev_info *entry;
 130
 131         if (dev_info == NULL)
 132                 return -EINVAL;
 133         for (minor = 0; minor < (1<<MINORBITS); minor++) {
 134                 found = 0;
 135                 // test if minor available
 136                 list_for_each_entry(entry, &dcssblk_devices, lh)
 137                         if (minor == MINOR(disk_devt(entry->gd)))
 138                                 found++;
 139                 if (!found) break; // got unused minor
 140         }
 141         if (found)
 142                 return -EBUSY;
 143         dev_info->gd->first_minor = minor;
 144         return 0;
 145 }
 146
 147 /*
 148  * get the struct dcssblk_dev_info from dcssblk_devices
 149  * for the given name.
 150  * down_read(&dcssblk_devices_sem) must be held.
 151  */
 152 static struct dcssblk_dev_info *
 153 dcssblk_get_device_by_name(char *name)
 154 {
 155         struct dcssblk_dev_info *entry;
 156
 157         list_for_each_entry(entry, &dcssblk_devices, lh) {
 158                 if (!strcmp(name, entry->segment_name)) {
 159                         return entry;
 160                 }
 161         }
 162         return NULL;
 163 }
 164
 165 /*
 166  * get the struct segment_info from seg_list
 167  * for the given name.
 168  * down_read(&dcssblk_devices_sem) must be held.
 169  */
 170 static struct segment_info *
 171 dcssblk_get_segment_by_name(char *name)
 172 {
 173         struct dcssblk_dev_info *dev_info;
 174         struct segment_info *entry;
 175
 176         list_for_each_entry(dev_info, &dcssblk_devices, lh) {
 177                 list_for_each_entry(entry, &dev_info->seg_list, lh) {
 178                         if (!strcmp(name, entry->segment_name))
 179                                 return entry;
 180                 }
 181         }
 182         return NULL;
 183 }
 184
 185 /*
 186  * get the highest address of the multi-segment block.
 187  */
 188 static unsigned long
 189 dcssblk_find_highest_addr(struct dcssblk_dev_info *dev_info)
 190 {
 191         unsigned long highest_addr;
 192         struct segment_info *entry;
 193
 194         highest_addr = 0;
 195         list_for_each_entry(entry, &dev_info->seg_list, lh) {
 196                 if (highest_addr < entry->end)
 197                         highest_addr = entry->end;
 198         }
 199         return highest_addr;
 200 }
 201
 202 /*
 203  * get the lowest address of the multi-segment block.
 204  */
 205 static unsigned long
 206 dcssblk_find_lowest_addr(struct dcssblk_dev_info *dev_info)
 207 {
 208         int set_first;
 209         unsigned long lowest_addr;
 210         struct segment_info *entry;
 211
 212         set_first = 0;
 213         lowest_addr = 0;
 214         list_for_each_entry(entry, &dev_info->seg_list, lh) {
 215                 if (set_first == 0) {
 216                         lowest_addr = entry->start;
 217                         set_first = 1;
 218                 } else {
 219                         if (lowest_addr > entry->start)
 220                                 lowest_addr = entry->start;
 221                 }
 222         }
 223         return lowest_addr;
 224 }
 225
 226 /*
 227  * Check continuity of segments.
 228  */
 229 static int
 230 dcssblk_is_continuous(struct dcssblk_dev_info *dev_info)
 231 {
 232         int i, j, rc;
 233         struct segment_info *sort_list, *entry, temp;
 234
 235         if (dev_info->num_of_segments <= 1)
 236                 return 0;
 237
 238         sort_list = kzalloc(
 239                         sizeof(struct segment_info) * dev_info->num_of_segments,
 240                         GFP_KERNEL);
 241         if (sort_list == NULL)
 242                 return -ENOMEM;
 243         i = 0;
 244         list_for_each_entry(entry, &dev_info->seg_list, lh) {
 245                 memcpy(&sort_list[i], entry, sizeof(struct segment_info));
 246                 i++;
 247         }
 248
 249         /* sort segments */
 250         for (i = 0; i < dev_info->num_of_segments; i++)
 251                 for (j = 0; j < dev_info->num_of_segments; j++)
 252                         if (sort_list[j].start > sort_list[i].start) {
 253                                 memcpy(&temp, &sort_list[i],
 254                                         sizeof(struct segment_info));
 255                                 memcpy(&sort_list[i], &sort_list[j],
 256                                         sizeof(struct segment_info));
 257                                 memcpy(&sort_list[j], &temp,
 258                                         sizeof(struct segment_info));
 259                         }
 260
 261         /* check continuity */
 262         for (i = 0; i < dev_info->num_of_segments - 1; i++) {
 263                 if ((sort_list[i].end + 1) != sort_list[i+1].start) {
 264                         PRINT_ERR("Segment %s is not contiguous with "
 265                                 "segment %s\n",
 266                                 sort_list[i].segment_name,
 267                                 sort_list[i+1].segment_name);
 268                         rc = -EINVAL;
 269                         goto out;
 270                 }
 271                 /* EN and EW are allowed in a block device */
 272                 if (sort_list[i].segment_type != sort_list[i+1].segment_type) {
 273                         if (!(sort_list[i].segment_type & SEGMENT_EXCLUSIVE) ||
 274                                 (sort_list[i].segment_type == SEG_TYPE_ER) ||
 275                                 !(sort_list[i+1].segment_type &
 276                                 SEGMENT_EXCLUSIVE) ||
 277                                 (sort_list[i+1].segment_type == SEG_TYPE_ER)) {
 278                                 PRINT_ERR("Segment %s has different type from "
 279                                         "segment %s\n",
 280                                         sort_list[i].segment_name,
 281                                         sort_list[i+1].segment_name);
 282                                 rc = -EINVAL;
 283                                 goto out;
 284                         }
 285                 }
 286         }
 287         rc = 0;
 288 out:
 289         kfree(sort_list);
 290         return rc;
 291 }
 292
 293 /*
 294  * Load a segment
 295  */
 296 static int
 297 dcssblk_load_segment(char *name, struct segment_info **seg_info)
 298 {
 299         int rc;
 300
 301         /* already loaded? */
 302         down_read(&dcssblk_devices_sem);
 303         *seg_info = dcssblk_get_segment_by_name(name);
 304         up_read(&dcssblk_devices_sem);
 305         if (*seg_info != NULL)
 306                 return -EEXIST;
 307
 308         /* get a struct segment_info */
 309         *seg_info = kzalloc(sizeof(struct segment_info), GFP_KERNEL);
 310         if (*seg_info == NULL)
 311                 return -ENOMEM;
 312
 313         strcpy((*seg_info)->segment_name, name);
 314
 315         /* load the segment */
 316         rc = segment_load(name, SEGMENT_SHARED,
 317                         &(*seg_info)->start, &(*seg_info)->end);
 318         if (rc < 0) {
 319                 segment_warning(rc, (*seg_info)->segment_name);
 320                 kfree(*seg_info);
 321         } else {
 322                 INIT_LIST_HEAD(&(*seg_info)->lh);
 323                 (*seg_info)->segment_type = rc;
 324         }
 325         return rc;
 326 }
 327
 328 static void dcssblk_unregister_callback(struct device *dev)
 329 {
 330         device_unregister(dev);
 331         put_device(dev);
 332 }
 333
 334 /*
 335  * device attribute for switching shared/nonshared (exclusive)
 336  * operation (show + store)
 337  */
 338 static ssize_t
 339 dcssblk_shared_show(struct device *dev, struct device_attribute *attr, char *buf)
 340 {
 341         struct dcssblk_dev_info *dev_info;
 342
 343         dev_info = container_of(dev, struct dcssblk_dev_info, dev);
 344         return sprintf(buf, dev_info->is_shared ? "1\n" : "0\n");
 345 }
 346
 347 static ssize_t
 348 dcssblk_shared_store(struct device *dev, struct device_attribute *attr, const char *inbuf, size_t count)
 349 {
 350         struct dcssblk_dev_info *dev_info;
 351         struct segment_info *entry, *temp;
 352         int rc;
 353
 354         if ((count > 1) && (inbuf[1] != '\n') && (inbuf[1] != '\0'))
 355                 return -EINVAL;
 356         down_write(&dcssblk_devices_sem);
 357         dev_info = container_of(dev, struct dcssblk_dev_info, dev);
 358         if (atomic_read(&dev_info->use_count)) {
 359                 rc = -EBUSY;
 360                 goto out;
 361         }
 362         if (inbuf[0] == '1') {
 363                 /* reload segments in shared mode */
 364                 list_for_each_entry(entry, &dev_info->seg_list, lh) {
 365                         rc = segment_modify_shared(entry->segment_name,
 366                                                 SEGMENT_SHARED);
 367                         if (rc < 0) {
 368                                 BUG_ON(rc == -EINVAL);
 369                                 if (rc != -EAGAIN)
 370                                         goto removeseg;
 371                         }
 372                 }
 373                 dev_info->is_shared = 1;
 374                 switch (dev_info->segment_type) {
 375                 case SEG_TYPE_SR:
 376                 case SEG_TYPE_ER:
 377                 case SEG_TYPE_SC:
 378                         set_disk_ro(dev_info->gd, 1);
 379                 }
 380         } else if (inbuf[0] == '0') {
 381                 /* reload segments in exclusive mode */
 382                 if (dev_info->segment_type == SEG_TYPE_SC) {
 383                         PRINT_ERR("Segment type SC (%s) cannot be loaded in "
 384                                 "non-shared mode\n", dev_info->segment_name);
 385                         rc = -EINVAL;
 386                         goto out;
 387                 }
 388                 list_for_each_entry(entry, &dev_info->seg_list, lh) {
 389                         rc = segment_modify_shared(entry->segment_name,
 390                                                    SEGMENT_EXCLUSIVE);
 391                         if (rc < 0) {
 392                                 BUG_ON(rc == -EINVAL);
 393                                 if (rc != -EAGAIN)
 394                                         goto removeseg;
 395                         }
 396                 }
 397                 dev_info->is_shared = 0;
 398                 set_disk_ro(dev_info->gd, 0);
 399         } else {
 400                 rc = -EINVAL;
 401                 goto out;
 402         }
 403         rc = count;
 404         goto out;
 405
 406 removeseg:
 407         PRINT_ERR("Could not reload segment(s) of the device %s, removing "
 408                 "segment(s) now!\n",
 409                 dev_info->segment_name);
 410         temp = entry;
 411         list_for_each_entry(entry, &dev_info->seg_list, lh) {
 412                 if (entry != temp)
 413                         segment_unload(entry->segment_name);
 414         }
 415         list_del(&dev_info->lh);
 416
 417         del_gendisk(dev_info->gd);
 418         blk_cleanup_queue(dev_info->dcssblk_queue);
 419         dev_info->gd->queue = NULL;
 420         put_disk(dev_info->gd);
 421         rc = device_schedule_callback(dev, dcssblk_unregister_callback);
 422 out:
 423         up_write(&dcssblk_devices_sem);
 424         return rc;
 425 }
 426
 427 /*
 428  * device attribute for save operation on current copy
 429  * of the segment. If the segment is busy, saving will
 430  * become pending until it gets released, which can be
 431  * undone by storing a non-true value to this entry.
 432  * (show + store)
 433  */
 434 static ssize_t
 435 dcssblk_save_show(struct device *dev, struct device_attribute *attr, char *buf)
 436 {
 437         struct dcssblk_dev_info *dev_info;
 438
 439         dev_info = container_of(dev, struct dcssblk_dev_info, dev);
 440         return sprintf(buf, dev_info->save_pending ? "1\n" : "0\n");
 441 }
 442
 443 static ssize_t
 444 dcssblk_save_store(struct device *dev, struct device_attribute *attr, const char *inbuf, size_t count)
 445 {
 446         struct dcssblk_dev_info *dev_info;
 447         struct segment_info *entry;
 448
 449         if ((count > 1) && (inbuf[1] != '\n') && (inbuf[1] != '\0'))
 450                 return -EINVAL;
 451         dev_info = container_of(dev, struct dcssblk_dev_info, dev);
 452
 453         down_write(&dcssblk_devices_sem);
 454         if (inbuf[0] == '1') {
 455                 if (atomic_read(&dev_info->use_count) == 0) {
 456                         // device is idle => we save immediately
 457                         PRINT_INFO("Saving segment(s) of the device %s\n",
 458                                    dev_info->segment_name);
 459                         list_for_each_entry(entry, &dev_info->seg_list, lh) {
 460                                 segment_save(entry->segment_name);
 461                         }
 462                 }  else {
 463                         // device is busy => we save it when it becomes
 464                         // idle in dcssblk_release
 465                         PRINT_INFO("Device %s is currently busy, segment(s) "
 466                                    "will be saved when it becomes idle...\n",
 467                                    dev_info->segment_name);
 468                         dev_info->save_pending = 1;
 469                 }
 470         } else if (inbuf[0] == '0') {
 471                 if (dev_info->save_pending) {
 472                         // device is busy & the user wants to undo his save
 473                         // request
 474                         dev_info->save_pending = 0;
 475                         PRINT_INFO("Pending save for segment(s) of the device "
 476                                         "%s deactivated\n",
 477                                         dev_info->segment_name);
 478                 }
 479         } else {
 480                 up_write(&dcssblk_devices_sem);
 481                 return -EINVAL;
 482         }
 483         up_write(&dcssblk_devices_sem);
 484         return count;
 485 }
 486
 487 /*
 488  * device attribute for showing all segments in a device
 489  */
 490 static ssize_t
 491 dcssblk_seglist_show(struct device *dev, struct device_attribute *attr,
 492                 char *buf)
 493 {
 494         int i;
 495
 496         struct dcssblk_dev_info *dev_info;
 497         struct segment_info *entry;
 498
 499         down_read(&dcssblk_devices_sem);
 500         dev_info = container_of(dev, struct dcssblk_dev_info, dev);
 501         i = 0;
 502         buf[0] = '\0';
 503         list_for_each_entry(entry, &dev_info->seg_list, lh) {
 504                 strcpy(&buf[i], entry->segment_name);
 505                 i += strlen(entry->segment_name);
 506                 buf[i] = '\n';
 507                 i++;
 508         }
 509         up_read(&dcssblk_devices_sem);
 510         return i;
 511 }
 512
 513 /*
 514  * device attribute for adding devices
 515  */
 516 static ssize_t
 517 dcssblk_add_store(struct device *dev, struct device_attribute *attr, const char *buf, size_t count)
 518 {
 519         int rc, i, j, num_of_segments;
 520         struct dcssblk_dev_info *dev_info;
 521         struct segment_info *seg_info, *temp;
 522         char *local_buf;
 523         unsigned long seg_byte_size;
 524
 525         dev_info = NULL;
 526         seg_info = NULL;
 527         if (dev != dcssblk_root_dev) {
 528                 rc = -EINVAL;
 529                 goto out_nobuf;
 530         }
 531         if ((count < 1) || (buf[0] == '\0') || (buf[0] == '\n')) {
 532                 rc = -ENAMETOOLONG;
 533                 goto out_nobuf;
 534         }
 535
 536         local_buf = kmalloc(count + 1, GFP_KERNEL);
 537         if (local_buf == NULL) {
 538                 rc = -ENOMEM;
 539                 goto out_nobuf;
 540         }
 541
 542         /*
 543          * parse input
 544          */
 545         num_of_segments = 0;
 546         for (i = 0; ((buf[i] != '\0') && (buf[i] != '\n') && i < count); i++) {
 547                 for (j = i; (buf[j] != ':') &&
 548                         (buf[j] != '\0') &&
 549                         (buf[j] != '\n') &&
 550                         j < count; j++) {
 551                         local_buf[j-i] = toupper(buf[j]);
 552                 }
 553                 local_buf[j-i] = '\0';
 554                 if (((j - i) == 0) || ((j - i) > 8)) {
 555                         rc = -ENAMETOOLONG;
 556                         goto seg_list_del;
 557                 }
 558
 559                 rc = dcssblk_load_segment(local_buf, &seg_info);
 560                 if (rc < 0)
 561                         goto seg_list_del;
 562                 /*
 563                  * get a struct dcssblk_dev_info
 564                  */
 565                 if (num_of_segments == 0) {
 566                         dev_info = kzalloc(sizeof(struct dcssblk_dev_info),
 567                                         GFP_KERNEL);
 568                         if (dev_info == NULL) {
 569                                 rc = -ENOMEM;
 570                                 goto out;
 571                         }
 572                         strcpy(dev_info->segment_name, local_buf);
 573                         dev_info->segment_type = seg_info->segment_type;
 574                         INIT_LIST_HEAD(&dev_info->seg_list);
 575                 }
 576                 list_add_tail(&seg_info->lh, &dev_info->seg_list);
 577                 num_of_segments++;
 578                 i = j;
 579
 580                 if ((buf[j] == '\0') || (buf[j] == '\n'))
 581                         break;
 582         }
 583
 584         /* no trailing colon at the end of the input */
 585         if ((i > 0) && (buf[i-1] == ':')) {
 586                 rc = -ENAMETOOLONG;
 587                 goto seg_list_del;
 588         }
 589         strlcpy(local_buf, buf, i + 1);
 590         dev_info->num_of_segments = num_of_segments;
 591         rc = dcssblk_is_continuous(dev_info);
 592         if (rc < 0)
 593                 goto seg_list_del;
 594
 595         dev_info->start = dcssblk_find_lowest_addr(dev_info);
 596         dev_info->end = dcssblk_find_highest_addr(dev_info);
 597
 598         dev_set_name(&dev_info->dev, dev_info->segment_name);
 599         dev_info->dev.release = dcssblk_release_segment;
 600         INIT_LIST_HEAD(&dev_info->lh);
 601         dev_info->gd = alloc_disk(DCSSBLK_MINORS_PER_DISK);
 602         if (dev_info->gd == NULL) {
 603                 rc = -ENOMEM;
 604                 goto seg_list_del;
 605         }
 606         dev_info->gd->major = dcssblk_major;
 607         dev_info->gd->fops = &dcssblk_devops;
 608         dev_info->dcssblk_queue = blk_alloc_queue(GFP_KERNEL);
 609         dev_info->gd->queue = dev_info->dcssblk_queue;
 610         dev_info->gd->private_data = dev_info;
 611         dev_info->gd->driverfs_dev = &dev_info->dev;
 612         blk_queue_make_request(dev_info->dcssblk_queue, dcssblk_make_request);
 613         blk_queue_hardsect_size(dev_info->dcssblk_queue, 4096);
 614
 615         seg_byte_size = (dev_info->end - dev_info->start + 1);
 616         set_capacity(dev_info->gd, seg_byte_size >> 9); // size in sectors
 617         PRINT_INFO("Loaded segment(s) %s, size = %lu Byte, "
 618                    "capacity = %lu (512 Byte) sectors\n", local_buf,
 619                    seg_byte_size, seg_byte_size >> 9);
 620
 621         dev_info->save_pending = 0;
 622         dev_info->is_shared = 1;
 623         dev_info->dev.parent = dcssblk_root_dev;
 624
 625         /*
 626          *get minor, add to list
 627          */
 628         down_write(&dcssblk_devices_sem);
 629         if (dcssblk_get_segment_by_name(local_buf)) {
 630                 rc = -EEXIST;
 631                 goto release_gd;
 632         }
 633         rc = dcssblk_assign_free_minor(dev_info);
 634         if (rc)
 635                 goto release_gd;
 636         sprintf(dev_info->gd->disk_name, "dcssblk%d",
 637                 MINOR(disk_devt(dev_info->gd)));
 638         list_add_tail(&dev_info->lh, &dcssblk_devices);
 639
 640         if (!try_module_get(THIS_MODULE)) {
 641                 rc = -ENODEV;
 642                 goto dev_list_del;
 643         }
 644         /*
 645          * register the device
 646          */
 647         rc = device_register(&dev_info->dev);
 648         if (rc) {
 649                 module_put(THIS_MODULE);
 650                 goto dev_list_del;
 651         }
 652         get_device(&dev_info->dev);
 653         rc = device_create_file(&dev_info->dev, &dev_attr_shared);
 654         if (rc)
 655                 goto unregister_dev;
 656         rc = device_create_file(&dev_info->dev, &dev_attr_save);
 657         if (rc)
 658                 goto unregister_dev;
 659         rc = device_create_file(&dev_info->dev, &dev_attr_seglist);
 660         if (rc)
 661                 goto unregister_dev;
 662
 663         add_disk(dev_info->gd);
 664
 665         switch (dev_info->segment_type) {
 666                 case SEG_TYPE_SR:
 667                 case SEG_TYPE_ER:
 668                 case SEG_TYPE_SC:
 669                         set_disk_ro(dev_info->gd,1);
 670                         break;
 671                 default:
 672                         set_disk_ro(dev_info->gd,0);
 673                         break;
 674         }
 675         up_write(&dcssblk_devices_sem);
 676         rc = count;
 677         goto out;
 678
 679 unregister_dev:
 680         list_del(&dev_info->lh);
 681         blk_cleanup_queue(dev_info->dcssblk_queue);
 682         dev_info->gd->queue = NULL;
 683         put_disk(dev_info->gd);
 684         device_unregister(&dev_info->dev);
 685         list_for_each_entry(seg_info, &dev_info->seg_list, lh) {
 686                 segment_unload(seg_info->segment_name);
 687         }
 688         put_device(&dev_info->dev);
 689         up_write(&dcssblk_devices_sem);
 690         goto out;
 691 dev_list_del:
 692         list_del(&dev_info->lh);
 693 release_gd:
 694         blk_cleanup_queue(dev_info->dcssblk_queue);
 695         dev_info->gd->queue = NULL;
 696         put_disk(dev_info->gd);
 697         up_write(&dcssblk_devices_sem);
 698 seg_list_del:
 699         if (dev_info == NULL)
 700                 goto out;
 701         list_for_each_entry_safe(seg_info, temp, &dev_info->seg_list, lh) {
 702                 list_del(&seg_info->lh);
 703                 segment_unload(seg_info->segment_name);
 704                 kfree(seg_info);
 705         }
 706         kfree(dev_info);
 707 out:
 708         kfree(local_buf);
 709 out_nobuf:
 710         return rc;
 711 }
 712
 713 /*
 714  * device attribute for removing devices
 715  */
 716 static ssize_t
 717 dcssblk_remove_store(struct device *dev, struct device_attribute *attr, const char *buf, size_t count)
 718 {
 719         struct dcssblk_dev_info *dev_info;
 720         struct segment_info *entry;
 721         int rc, i;
 722         char *local_buf;
 723
 724         if (dev != dcssblk_root_dev) {
 725                 return -EINVAL;
 726         }
 727         local_buf = kmalloc(count + 1, GFP_KERNEL);
 728         if (local_buf == NULL) {
 729                 return -ENOMEM;
 730         }
 731         /*
 732          * parse input
 733          */
 734         for (i = 0; ((*(buf+i)!='\0') && (*(buf+i)!='\n') && i < count); i++) {
 735                 local_buf[i] = toupper(buf[i]);
 736         }
 737         local_buf[i] = '\0';
 738         if ((i == 0) || (i > 8)) {
 739                 rc = -ENAMETOOLONG;
 740                 goto out_buf;
 741         }
 742
 743         down_write(&dcssblk_devices_sem);
 744         dev_info = dcssblk_get_device_by_name(local_buf);
 745         if (dev_info == NULL) {
 746                 up_write(&dcssblk_devices_sem);
 747                 PRINT_WARN("Device %s is not loaded!\n", local_buf);
 748                 rc = -ENODEV;
 749                 goto out_buf;
 750         }
 751         if (atomic_read(&dev_info->use_count) != 0) {
 752                 up_write(&dcssblk_devices_sem);
 753                 PRINT_WARN("Device %s is in use!\n", local_buf);
 754                 rc = -EBUSY;
 755                 goto out_buf;
 756         }
 757
 758         list_del(&dev_info->lh);
 759         del_gendisk(dev_info->gd);
 760         blk_cleanup_queue(dev_info->dcssblk_queue);
 761         dev_info->gd->queue = NULL;
 762         put_disk(dev_info->gd);
 763         device_unregister(&dev_info->dev);
 764
 765         /* unload all related segments */
 766         list_for_each_entry(entry, &dev_info->seg_list, lh)
 767                 segment_unload(entry->segment_name);
 768
 769         put_device(&dev_info->dev);
 770         up_write(&dcssblk_devices_sem);
 771
 772         rc = count;
 773 out_buf:
 774         kfree(local_buf);
 775         return rc;
 776 }
 777
 778 static int
 779 dcssblk_open(struct inode *inode, struct file *filp)
 780 {
 781         struct dcssblk_dev_info *dev_info;
 782         int rc;
 783
 784         dev_info = inode->i_bdev->bd_disk->private_data;
 785         if (NULL == dev_info) {
 786                 rc = -ENODEV;
 787                 goto out;
 788         }
 789         atomic_inc(&dev_info->use_count);
 790         inode->i_bdev->bd_block_size = 4096;
 791         rc = 0;
 792 out:
 793         return rc;
 794 }
 795
 796 static int
 797 dcssblk_release(struct inode *inode, struct file *filp)
 798 {
 799         struct dcssblk_dev_info *dev_info;
 800         struct segment_info *entry;
 801         int rc;
 802
 803         dev_info = inode->i_bdev->bd_disk->private_data;
 804         if (NULL == dev_info) {
 805                 rc = -ENODEV;
 806                 goto out;
 807         }
 808         down_write(&dcssblk_devices_sem);
 809         if (atomic_dec_and_test(&dev_info->use_count)
 810             && (dev_info->save_pending)) {
 811                 PRINT_INFO("Device %s became idle and is being saved now\n",
 812                             dev_info->segment_name);
 813                 list_for_each_entry(entry, &dev_info->seg_list, lh) {
 814                         segment_save(entry->segment_name);
 815                 }
 816                 dev_info->save_pending = 0;
 817         }
 818         up_write(&dcssblk_devices_sem);
 819         rc = 0;
 820 out:
 821         return rc;
 822 }
 823
 824 static int
 825 dcssblk_make_request(struct request_queue *q, struct bio *bio)
 826 {
 827         struct dcssblk_dev_info *dev_info;
 828         struct bio_vec *bvec;
 829         unsigned long index;
 830         unsigned long page_addr;
 831         unsigned long source_addr;
 832         unsigned long bytes_done;
 833         int i;
 834
 835         bytes_done = 0;
 836         dev_info = bio->bi_bdev->bd_disk->private_data;
 837         if (dev_info == NULL)
 838                 goto fail;
 839         if ((bio->bi_sector & 7) != 0 || (bio->bi_size & 4095) != 0)
 840                 /* Request is not page-aligned. */
 841                 goto fail;
 842         if (((bio->bi_size >> 9) + bio->bi_sector)
 843                         > get_capacity(bio->bi_bdev->bd_disk)) {
 844                 /* Request beyond end of DCSS segment. */
 845                 goto fail;
 846         }
 847         /* verify data transfer direction */
 848         if (dev_info->is_shared) {
 849                 switch (dev_info->segment_type) {
 850                 case SEG_TYPE_SR:
 851                 case SEG_TYPE_ER:
 852                 case SEG_TYPE_SC:
 853                         /* cannot write to these segments */
 854                         if (bio_data_dir(bio) == WRITE) {
 855                                 PRINT_WARN("rejecting write to ro device %s\n",
 856                                            dev_name(&dev_info->dev));
 857                                 goto fail;
 858                         }
 859                 }
 860         }
 861
 862         index = (bio->bi_sector >> 3);
 863         bio_for_each_segment(bvec, bio, i) {
 864                 page_addr = (unsigned long)
 865                         page_address(bvec->bv_page) + bvec->bv_offset;
 866                 source_addr = dev_info->start + (index<<12) + bytes_done;
 867                 if (unlikely((page_addr & 4095) != 0) || (bvec->bv_len & 4095) != 0)
 868                         // More paranoia.
 869                         goto fail;
 870                 if (bio_data_dir(bio) == READ) {
 871                         memcpy((void*)page_addr, (void*)source_addr,
 872                                 bvec->bv_len);
 873                 } else {
 874                         memcpy((void*)source_addr, (void*)page_addr,
 875                                 bvec->bv_len);
 876                 }
 877                 bytes_done += bvec->bv_len;
 878         }
 879         bio_endio(bio, 0);
 880         return 0;
 881 fail:
 882         bio_io_error(bio);
 883         return 0;
 884 }
 885
 886 static int
 887 dcssblk_direct_access (struct block_device *bdev, sector_t secnum,
 888                         void **kaddr, unsigned long *pfn)
 889 {
 890         struct dcssblk_dev_info *dev_info;
 891         unsigned long pgoff;
 892
 893         dev_info = bdev->bd_disk->private_data;
 894         if (!dev_info)
 895                 return -ENODEV;
 896         if (secnum % (PAGE_SIZE/512))
 897                 return -EINVAL;
 898         pgoff = secnum / (PAGE_SIZE / 512);
 899         if ((pgoff+1)*PAGE_SIZE-1 > dev_info->end - dev_info->start)
 900                 return -ERANGE;
 901         *kaddr = (void *) (dev_info->start+pgoff*PAGE_SIZE);
 902         *pfn = virt_to_phys(*kaddr) >> PAGE_SHIFT;
 903
 904         return 0;
 905 }
 906
 907 static void
 908 dcssblk_check_params(void)
 909 {
 910         int rc, i, j, k;
 911         char buf[DCSSBLK_PARM_LEN + 1];
 912         struct dcssblk_dev_info *dev_info;
 913
 914         for (i = 0; (i < DCSSBLK_PARM_LEN) && (dcssblk_segments[i] != '\0');
 915              i++) {
 916                 for (j = i; (dcssblk_segments[j] != ',')  &&
 917                             (dcssblk_segments[j] != '\0') &&
 918                             (dcssblk_segments[j] != '(')  &&
 919                             (j < DCSSBLK_PARM_LEN); j++)
 920                 {
 921                         buf[j-i] = dcssblk_segments[j];
 922                 }
 923                 buf[j-i] = '\0';
 924                 rc = dcssblk_add_store(dcssblk_root_dev, NULL, buf, j-i);
 925                 if ((rc >= 0) && (dcssblk_segments[j] == '(')) {
 926                         for (k = 0; (buf[k] != ':') && (buf[k] != '\0'); k++)
 927                                 buf[k] = toupper(buf[k]);
 928                         buf[k] = '\0';
 929                         if (!strncmp(&dcssblk_segments[j], "(local)", 7)) {
 930                                 down_read(&dcssblk_devices_sem);
 931                                 dev_info = dcssblk_get_device_by_name(buf);
 932                                 up_read(&dcssblk_devices_sem);
 933                                 if (dev_info)
 934                                         dcssblk_shared_store(&dev_info->dev,
 935                                                              NULL, "0\n", 2);
 936                         }
 937                 }
 938                 while ((dcssblk_segments[j] != ',') &&
 939                        (dcssblk_segments[j] != '\0'))
 940                 {
 941                         j++;
 942                 }
 943                 if (dcssblk_segments[j] == '\0')
 944                         break;
 945                 i = j;
 946         }
 947 }
 948
 949 /*
 950  * The init/exit functions.
 951  */
 952 static void __exit
 953 dcssblk_exit(void)
 954 {
 955         s390_root_dev_unregister(dcssblk_root_dev);
 956         unregister_blkdev(dcssblk_major, DCSSBLK_NAME);
 957 }
 958
 959 static int __init
 960 dcssblk_init(void)
 961 {
 962         int rc;
 963
 964         dcssblk_root_dev = s390_root_dev_register("dcssblk");
 965         if (IS_ERR(dcssblk_root_dev))
 966                 return PTR_ERR(dcssblk_root_dev);
 967         rc = device_create_file(dcssblk_root_dev, &dev_attr_add);
 968         if (rc) {
 969                 s390_root_dev_unregister(dcssblk_root_dev);
 970                 return rc;
 971         }
 972         rc = device_create_file(dcssblk_root_dev, &dev_attr_remove);
 973         if (rc) {
 974                 s390_root_dev_unregister(dcssblk_root_dev);
 975                 return rc;
 976         }
 977         rc = register_blkdev(0, DCSSBLK_NAME);
 978         if (rc < 0) {
 979                 s390_root_dev_unregister(dcssblk_root_dev);
 980                 return rc;
 981         }
 982         dcssblk_major = rc;
 983         init_rwsem(&dcssblk_devices_sem);
 984
 985         dcssblk_check_params();
 986
 987         return 0;
 988 }
 989
 990 module_init(dcssblk_init);
 991 module_exit(dcssblk_exit);
 992
 993 module_param_string(segments, dcssblk_segments, DCSSBLK_PARM_LEN, 0444);
 994 MODULE_PARM_DESC(segments, "Name of DCSS segment(s) to be loaded, "
 995                  "comma-separated list, names in each set separated "
 996                  "by commas are separated by colons, each set contains "
 997                  "names of contiguous segments and each name max. 8 chars.\n"
 998                  "Adding \"(local)\" to the end of each set equals echoing 0 "
 999                  "to /sys/devices/dcssblk/<device name>/shared after loading "
1000                  "the contiguous segments - \n"
1001                  "e.g. segments=\"mydcss1,mydcss2:mydcss3,mydcss4(local)\"");
1002
1003 MODULE_LICENSE("GPL");