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 #define KMSG_COMPONENT "dcssblk"
   8 #define pr_fmt(fmt) KMSG_COMPONENT ": " fmt
   9
  10 #include <linux/module.h>
  11 #include <linux/moduleparam.h>
  12 #include <linux/ctype.h>
  13 #include <linux/errno.h>
  14 #include <linux/init.h>
  15 #include <linux/slab.h>
  16 #include <linux/blkdev.h>
  17 #include <asm/extmem.h>
  18 #include <asm/io.h>
  19 #include <linux/completion.h>
  20 #include <linux/interrupt.h>
  21 #include <asm/s390_rdev.h>
  22
  23 #define DCSSBLK_NAME "dcssblk"
  24 #define DCSSBLK_MINORS_PER_DISK 1
  25 #define DCSSBLK_PARM_LEN 400
  26 #define DCSS_BUS_ID_SIZE 20
  27
  28 static int dcssblk_open(struct block_device *bdev, fmode_t mode);
  29 static int dcssblk_release(struct gendisk *disk, fmode_t mode);
  30 static int dcssblk_make_request(struct request_queue *q, struct bio *bio);
  31 static int dcssblk_direct_access(struct block_device *bdev, sector_t secnum,
  32                                  void **kaddr, unsigned long *pfn);
  33
  34 static char dcssblk_segments[DCSSBLK_PARM_LEN] = "\0";
  35
  36 static int dcssblk_major;
  37 static struct block_device_operations dcssblk_devops = {
  38         .owner          = THIS_MODULE,
  39         .open           = dcssblk_open,
  40         .release        = dcssblk_release,
  41         .direct_access  = dcssblk_direct_access,
  42 };
  43
  44 struct dcssblk_dev_info {
  45         struct list_head lh;
  46         struct device dev;
  47         char segment_name[DCSS_BUS_ID_SIZE];
  48         atomic_t use_count;
  49         struct gendisk *gd;
  50         unsigned long start;
  51         unsigned long end;
  52         int segment_type;
  53         unsigned char save_pending;
  54         unsigned char is_shared;
  55         struct request_queue *dcssblk_queue;
  56         int num_of_segments;
  57         struct list_head seg_list;
  58 };
  59
  60 struct segment_info {
  61         struct list_head lh;
  62         char segment_name[DCSS_BUS_ID_SIZE];
  63         unsigned long start;
  64         unsigned long end;
  65         int segment_type;
  66 };
  67
  68 static ssize_t dcssblk_add_store(struct device * dev, struct device_attribute *attr, const char * buf,
  69                                   size_t count);
  70 static ssize_t dcssblk_remove_store(struct device * dev, struct device_attribute *attr, const char * buf,
  71                                   size_t count);
  72 static ssize_t dcssblk_save_store(struct device * dev, struct device_attribute *attr, const char * buf,
  73                                   size_t count);
  74 static ssize_t dcssblk_save_show(struct device *dev, struct device_attribute *attr, char *buf);
  75 static ssize_t dcssblk_shared_store(struct device * dev, struct device_attribute *attr, const char * buf,
  76                                   size_t count);
  77 static ssize_t dcssblk_shared_show(struct device *dev, struct device_attribute *attr, char *buf);
  78 static ssize_t dcssblk_seglist_show(struct device *dev,
  79                                 struct device_attribute *attr,
  80                                 char *buf);
  81
  82 static DEVICE_ATTR(add, S_IWUSR, NULL, dcssblk_add_store);
  83 static DEVICE_ATTR(remove, S_IWUSR, NULL, dcssblk_remove_store);
  84 static DEVICE_ATTR(save, S_IWUSR | S_IRUSR, dcssblk_save_show,
  85                    dcssblk_save_store);
  86 static DEVICE_ATTR(shared, S_IWUSR | S_IRUSR, dcssblk_shared_show,
  87                    dcssblk_shared_store);
  88 static DEVICE_ATTR(seglist, S_IRUSR, dcssblk_seglist_show, NULL);
  89
  90 static struct device *dcssblk_root_dev;
  91
  92 static LIST_HEAD(dcssblk_devices);
  93 static struct rw_semaphore dcssblk_devices_sem;
  94
  95 /*
  96  * release function for segment device.
  97  */
  98 static void
  99 dcssblk_release_segment(struct device *dev)
 100 {
 101         struct dcssblk_dev_info *dev_info;
 102         struct segment_info *entry, *temp;
 103
 104         dev_info = container_of(dev, struct dcssblk_dev_info, dev);
 105         list_for_each_entry_safe(entry, temp, &dev_info->seg_list, lh) {
 106                 list_del(&entry->lh);
 107                 kfree(entry);
 108         }
 109         kfree(dev_info);
 110         module_put(THIS_MODULE);
 111 }
 112
 113 /*
 114  * get a minor number. needs to be called with
 115  * down_write(&dcssblk_devices_sem) and the
 116  * device needs to be enqueued before the semaphore is
 117  * freed.
 118  */
 119 static int
 120 dcssblk_assign_free_minor(struct dcssblk_dev_info *dev_info)
 121 {
 122         int minor, found;
 123         struct dcssblk_dev_info *entry;
 124
 125         if (dev_info == NULL)
 126                 return -EINVAL;
 127         for (minor = 0; minor < (1<<MINORBITS); minor++) {
 128                 found = 0;
 129                 // test if minor available
 130                 list_for_each_entry(entry, &dcssblk_devices, lh)
 131                         if (minor == MINOR(disk_devt(entry->gd)))
 132                                 found++;
 133                 if (!found) break; // got unused minor
 134         }
 135         if (found)
 136                 return -EBUSY;
 137         dev_info->gd->first_minor = minor;
 138         return 0;
 139 }
 140
 141 /*
 142  * get the struct dcssblk_dev_info from dcssblk_devices
 143  * for the given name.
 144  * down_read(&dcssblk_devices_sem) must be held.
 145  */
 146 static struct dcssblk_dev_info *
 147 dcssblk_get_device_by_name(char *name)
 148 {
 149         struct dcssblk_dev_info *entry;
 150
 151         list_for_each_entry(entry, &dcssblk_devices, lh) {
 152                 if (!strcmp(name, entry->segment_name)) {
 153                         return entry;
 154                 }
 155         }
 156         return NULL;
 157 }
 158
 159 /*
 160  * get the struct segment_info from seg_list
 161  * for the given name.
 162  * down_read(&dcssblk_devices_sem) must be held.
 163  */
 164 static struct segment_info *
 165 dcssblk_get_segment_by_name(char *name)
 166 {
 167         struct dcssblk_dev_info *dev_info;
 168         struct segment_info *entry;
 169
 170         list_for_each_entry(dev_info, &dcssblk_devices, lh) {
 171                 list_for_each_entry(entry, &dev_info->seg_list, lh) {
 172                         if (!strcmp(name, entry->segment_name))
 173                                 return entry;
 174                 }
 175         }
 176         return NULL;
 177 }
 178
 179 /*
 180  * get the highest address of the multi-segment block.
 181  */
 182 static unsigned long
 183 dcssblk_find_highest_addr(struct dcssblk_dev_info *dev_info)
 184 {
 185         unsigned long highest_addr;
 186         struct segment_info *entry;
 187
 188         highest_addr = 0;
 189         list_for_each_entry(entry, &dev_info->seg_list, lh) {
 190                 if (highest_addr < entry->end)
 191                         highest_addr = entry->end;
 192         }
 193         return highest_addr;
 194 }
 195
 196 /*
 197  * get the lowest address of the multi-segment block.
 198  */
 199 static unsigned long
 200 dcssblk_find_lowest_addr(struct dcssblk_dev_info *dev_info)
 201 {
 202         int set_first;
 203         unsigned long lowest_addr;
 204         struct segment_info *entry;
 205
 206         set_first = 0;
 207         lowest_addr = 0;
 208         list_for_each_entry(entry, &dev_info->seg_list, lh) {
 209                 if (set_first == 0) {
 210                         lowest_addr = entry->start;
 211                         set_first = 1;
 212                 } else {
 213                         if (lowest_addr > entry->start)
 214                                 lowest_addr = entry->start;
 215                 }
 216         }
 217         return lowest_addr;
 218 }
 219
 220 /*
 221  * Check continuity of segments.
 222  */
 223 static int
 224 dcssblk_is_continuous(struct dcssblk_dev_info *dev_info)
 225 {
 226         int i, j, rc;
 227         struct segment_info *sort_list, *entry, temp;
 228
 229         if (dev_info->num_of_segments <= 1)
 230                 return 0;
 231
 232         sort_list = kzalloc(
 233                         sizeof(struct segment_info) * dev_info->num_of_segments,
 234                         GFP_KERNEL);
 235         if (sort_list == NULL)
 236                 return -ENOMEM;
 237         i = 0;
 238         list_for_each_entry(entry, &dev_info->seg_list, lh) {
 239                 memcpy(&sort_list[i], entry, sizeof(struct segment_info));
 240                 i++;
 241         }
 242
 243         /* sort segments */
 244         for (i = 0; i < dev_info->num_of_segments; i++)
 245                 for (j = 0; j < dev_info->num_of_segments; j++)
 246                         if (sort_list[j].start > sort_list[i].start) {
 247                                 memcpy(&temp, &sort_list[i],
 248                                         sizeof(struct segment_info));
 249                                 memcpy(&sort_list[i], &sort_list[j],
 250                                         sizeof(struct segment_info));
 251                                 memcpy(&sort_list[j], &temp,
 252                                         sizeof(struct segment_info));
 253                         }
 254
 255         /* check continuity */
 256         for (i = 0; i < dev_info->num_of_segments - 1; i++) {
 257                 if ((sort_list[i].end + 1) != sort_list[i+1].start) {
 258                         pr_err("Adjacent DCSSs %s and %s are not "
 259                                "contiguous\n", sort_list[i].segment_name,
 260                                sort_list[i+1].segment_name);
 261                         rc = -EINVAL;
 262                         goto out;
 263                 }
 264                 /* EN and EW are allowed in a block device */
 265                 if (sort_list[i].segment_type != sort_list[i+1].segment_type) {
 266                         if (!(sort_list[i].segment_type & SEGMENT_EXCLUSIVE) ||
 267                                 (sort_list[i].segment_type == SEG_TYPE_ER) ||
 268                                 !(sort_list[i+1].segment_type &
 269                                 SEGMENT_EXCLUSIVE) ||
 270                                 (sort_list[i+1].segment_type == SEG_TYPE_ER)) {
 271                                 pr_err("DCSS %s and DCSS %s have "
 272                                        "incompatible types\n",
 273                                        sort_list[i].segment_name,
 274                                        sort_list[i+1].segment_name);
 275                                 rc = -EINVAL;
 276                                 goto out;
 277                         }
 278                 }
 279         }
 280         rc = 0;
 281 out:
 282         kfree(sort_list);
 283         return rc;
 284 }
 285
 286 /*
 287  * Load a segment
 288  */
 289 static int
 290 dcssblk_load_segment(char *name, struct segment_info **seg_info)
 291 {
 292         int rc;
 293
 294         /* already loaded? */
 295         down_read(&dcssblk_devices_sem);
 296         *seg_info = dcssblk_get_segment_by_name(name);
 297         up_read(&dcssblk_devices_sem);
 298         if (*seg_info != NULL)
 299                 return -EEXIST;
 300
 301         /* get a struct segment_info */
 302         *seg_info = kzalloc(sizeof(struct segment_info), GFP_KERNEL);
 303         if (*seg_info == NULL)
 304                 return -ENOMEM;
 305
 306         strcpy((*seg_info)->segment_name, name);
 307
 308         /* load the segment */
 309         rc = segment_load(name, SEGMENT_SHARED,
 310                         &(*seg_info)->start, &(*seg_info)->end);
 311         if (rc < 0) {
 312                 segment_warning(rc, (*seg_info)->segment_name);
 313                 kfree(*seg_info);
 314         } else {
 315                 INIT_LIST_HEAD(&(*seg_info)->lh);
 316                 (*seg_info)->segment_type = rc;
 317         }
 318         return rc;
 319 }
 320
 321 static void dcssblk_unregister_callback(struct device *dev)
 322 {
 323         device_unregister(dev);
 324         put_device(dev);
 325 }
 326
 327 /*
 328  * device attribute for switching shared/nonshared (exclusive)
 329  * operation (show + store)
 330  */
 331 static ssize_t
 332 dcssblk_shared_show(struct device *dev, struct device_attribute *attr, char *buf)
 333 {
 334         struct dcssblk_dev_info *dev_info;
 335
 336         dev_info = container_of(dev, struct dcssblk_dev_info, dev);
 337         return sprintf(buf, dev_info->is_shared ? "1\n" : "0\n");
 338 }
 339
 340 static ssize_t
 341 dcssblk_shared_store(struct device *dev, struct device_attribute *attr, const char *inbuf, size_t count)
 342 {
 343         struct dcssblk_dev_info *dev_info;
 344         struct segment_info *entry, *temp;
 345         int rc;
 346
 347         if ((count > 1) && (inbuf[1] != '\n') && (inbuf[1] != '\0'))
 348                 return -EINVAL;
 349         down_write(&dcssblk_devices_sem);
 350         dev_info = container_of(dev, struct dcssblk_dev_info, dev);
 351         if (atomic_read(&dev_info->use_count)) {
 352                 rc = -EBUSY;
 353                 goto out;
 354         }
 355         if (inbuf[0] == '1') {
 356                 /* reload segments in shared mode */
 357                 list_for_each_entry(entry, &dev_info->seg_list, lh) {
 358                         rc = segment_modify_shared(entry->segment_name,
 359                                                 SEGMENT_SHARED);
 360                         if (rc < 0) {
 361                                 BUG_ON(rc == -EINVAL);
 362                                 if (rc != -EAGAIN)
 363                                         goto removeseg;
 364                         }
 365                 }
 366                 dev_info->is_shared = 1;
 367                 switch (dev_info->segment_type) {
 368                 case SEG_TYPE_SR:
 369                 case SEG_TYPE_ER:
 370                 case SEG_TYPE_SC:
 371                         set_disk_ro(dev_info->gd, 1);
 372                 }
 373         } else if (inbuf[0] == '0') {
 374                 /* reload segments in exclusive mode */
 375                 if (dev_info->segment_type == SEG_TYPE_SC) {
 376                         pr_err("DCSS %s is of type SC and cannot be "
 377                                "loaded as exclusive-writable\n",
 378                                dev_info->segment_name);
 379                         rc = -EINVAL;
 380                         goto out;
 381                 }
 382                 list_for_each_entry(entry, &dev_info->seg_list, lh) {
 383                         rc = segment_modify_shared(entry->segment_name,
 384                                                    SEGMENT_EXCLUSIVE);
 385                         if (rc < 0) {
 386                                 BUG_ON(rc == -EINVAL);
 387                                 if (rc != -EAGAIN)
 388                                         goto removeseg;
 389                         }
 390                 }
 391                 dev_info->is_shared = 0;
 392                 set_disk_ro(dev_info->gd, 0);
 393         } else {
 394                 rc = -EINVAL;
 395                 goto out;
 396         }
 397         rc = count;
 398         goto out;
 399
 400 removeseg:
 401         pr_err("DCSS device %s is removed after a failed access mode "
 402                "change\n", dev_info->segment_name);
 403         temp = entry;
 404         list_for_each_entry(entry, &dev_info->seg_list, lh) {
 405                 if (entry != temp)
 406                         segment_unload(entry->segment_name);
 407         }
 408         list_del(&dev_info->lh);
 409
 410         del_gendisk(dev_info->gd);
 411         blk_cleanup_queue(dev_info->dcssblk_queue);
 412         dev_info->gd->queue = NULL;
 413         put_disk(dev_info->gd);
 414         rc = device_schedule_callback(dev, dcssblk_unregister_callback);
 415 out:
 416         up_write(&dcssblk_devices_sem);
 417         return rc;
 418 }
 419
 420 /*
 421  * device attribute for save operation on current copy
 422  * of the segment. If the segment is busy, saving will
 423  * become pending until it gets released, which can be
 424  * undone by storing a non-true value to this entry.
 425  * (show + store)
 426  */
 427 static ssize_t
 428 dcssblk_save_show(struct device *dev, struct device_attribute *attr, char *buf)
 429 {
 430         struct dcssblk_dev_info *dev_info;
 431
 432         dev_info = container_of(dev, struct dcssblk_dev_info, dev);
 433         return sprintf(buf, dev_info->save_pending ? "1\n" : "0\n");
 434 }
 435
 436 static ssize_t
 437 dcssblk_save_store(struct device *dev, struct device_attribute *attr, const char *inbuf, size_t count)
 438 {
 439         struct dcssblk_dev_info *dev_info;
 440         struct segment_info *entry;
 441
 442         if ((count > 1) && (inbuf[1] != '\n') && (inbuf[1] != '\0'))
 443                 return -EINVAL;
 444         dev_info = container_of(dev, struct dcssblk_dev_info, dev);
 445
 446         down_write(&dcssblk_devices_sem);
 447         if (inbuf[0] == '1') {
 448                 if (atomic_read(&dev_info->use_count) == 0) {
 449                         // device is idle => we save immediately
 450                         pr_info("All DCSSs that map to device %s are "
 451                                 "saved\n", dev_info->segment_name);
 452                         list_for_each_entry(entry, &dev_info->seg_list, lh) {
 453                                 segment_save(entry->segment_name);
 454                         }
 455                 }  else {
 456                         // device is busy => we save it when it becomes
 457                         // idle in dcssblk_release
 458                         pr_info("Device %s is in use, its DCSSs will be "
 459                                 "saved when it becomes idle\n",
 460                                 dev_info->segment_name);
 461                         dev_info->save_pending = 1;
 462                 }
 463         } else if (inbuf[0] == '0') {
 464                 if (dev_info->save_pending) {
 465                         // device is busy & the user wants to undo his save
 466                         // request
 467                         dev_info->save_pending = 0;
 468                         pr_info("A pending save request for device %s "
 469                                 "has been canceled\n",
 470                                 dev_info->segment_name);
 471                 }
 472         } else {
 473                 up_write(&dcssblk_devices_sem);
 474                 return -EINVAL;
 475         }
 476         up_write(&dcssblk_devices_sem);
 477         return count;
 478 }
 479
 480 /*
 481  * device attribute for showing all segments in a device
 482  */
 483 static ssize_t
 484 dcssblk_seglist_show(struct device *dev, struct device_attribute *attr,
 485                 char *buf)
 486 {
 487         int i;
 488
 489         struct dcssblk_dev_info *dev_info;
 490         struct segment_info *entry;
 491
 492         down_read(&dcssblk_devices_sem);
 493         dev_info = container_of(dev, struct dcssblk_dev_info, dev);
 494         i = 0;
 495         buf[0] = '\0';
 496         list_for_each_entry(entry, &dev_info->seg_list, lh) {
 497                 strcpy(&buf[i], entry->segment_name);
 498                 i += strlen(entry->segment_name);
 499                 buf[i] = '\n';
 500                 i++;
 501         }
 502         up_read(&dcssblk_devices_sem);
 503         return i;
 504 }
 505
 506 /*
 507  * device attribute for adding devices
 508  */
 509 static ssize_t
 510 dcssblk_add_store(struct device *dev, struct device_attribute *attr, const char *buf, size_t count)
 511 {
 512         int rc, i, j, num_of_segments;
 513         struct dcssblk_dev_info *dev_info;
 514         struct segment_info *seg_info, *temp;
 515         char *local_buf;
 516         unsigned long seg_byte_size;
 517
 518         dev_info = NULL;
 519         seg_info = NULL;
 520         if (dev != dcssblk_root_dev) {
 521                 rc = -EINVAL;
 522                 goto out_nobuf;
 523         }
 524         if ((count < 1) || (buf[0] == '\0') || (buf[0] == '\n')) {
 525                 rc = -ENAMETOOLONG;
 526                 goto out_nobuf;
 527         }
 528
 529         local_buf = kmalloc(count + 1, GFP_KERNEL);
 530         if (local_buf == NULL) {
 531                 rc = -ENOMEM;
 532                 goto out_nobuf;
 533         }
 534
 535         /*
 536          * parse input
 537          */
 538         num_of_segments = 0;
 539         for (i = 0; ((buf[i] != '\0') && (buf[i] != '\n') && i < count); i++) {
 540                 for (j = i; (buf[j] != ':') &&
 541                         (buf[j] != '\0') &&
 542                         (buf[j] != '\n') &&
 543                         j < count; j++) {
 544                         local_buf[j-i] = toupper(buf[j]);
 545                 }
 546                 local_buf[j-i] = '\0';
 547                 if (((j - i) == 0) || ((j - i) > 8)) {
 548                         rc = -ENAMETOOLONG;
 549                         goto seg_list_del;
 550                 }
 551
 552                 rc = dcssblk_load_segment(local_buf, &seg_info);
 553                 if (rc < 0)
 554                         goto seg_list_del;
 555                 /*
 556                  * get a struct dcssblk_dev_info
 557                  */
 558                 if (num_of_segments == 0) {
 559                         dev_info = kzalloc(sizeof(struct dcssblk_dev_info),
 560                                         GFP_KERNEL);
 561                         if (dev_info == NULL) {
 562                                 rc = -ENOMEM;
 563                                 goto out;
 564                         }
 565                         strcpy(dev_info->segment_name, local_buf);
 566                         dev_info->segment_type = seg_info->segment_type;
 567                         INIT_LIST_HEAD(&dev_info->seg_list);
 568                 }
 569                 list_add_tail(&seg_info->lh, &dev_info->seg_list);
 570                 num_of_segments++;
 571                 i = j;
 572
 573                 if ((buf[j] == '\0') || (buf[j] == '\n'))
 574                         break;
 575         }
 576
 577         /* no trailing colon at the end of the input */
 578         if ((i > 0) && (buf[i-1] == ':')) {
 579                 rc = -ENAMETOOLONG;
 580                 goto seg_list_del;
 581         }
 582         strlcpy(local_buf, buf, i + 1);
 583         dev_info->num_of_segments = num_of_segments;
 584         rc = dcssblk_is_continuous(dev_info);
 585         if (rc < 0)
 586                 goto seg_list_del;
 587
 588         dev_info->start = dcssblk_find_lowest_addr(dev_info);
 589         dev_info->end = dcssblk_find_highest_addr(dev_info);
 590
 591         dev_set_name(&dev_info->dev, dev_info->segment_name);
 592         dev_info->dev.release = dcssblk_release_segment;
 593         INIT_LIST_HEAD(&dev_info->lh);
 594         dev_info->gd = alloc_disk(DCSSBLK_MINORS_PER_DISK);
 595         if (dev_info->gd == NULL) {
 596                 rc = -ENOMEM;
 597                 goto seg_list_del;
 598         }
 599         dev_info->gd->major = dcssblk_major;
 600         dev_info->gd->fops = &dcssblk_devops;
 601         dev_info->dcssblk_queue = blk_alloc_queue(GFP_KERNEL);
 602         dev_info->gd->queue = dev_info->dcssblk_queue;
 603         dev_info->gd->private_data = dev_info;
 604         dev_info->gd->driverfs_dev = &dev_info->dev;
 605         blk_queue_make_request(dev_info->dcssblk_queue, dcssblk_make_request);
 606         blk_queue_hardsect_size(dev_info->dcssblk_queue, 4096);
 607
 608         seg_byte_size = (dev_info->end - dev_info->start + 1);
 609         set_capacity(dev_info->gd, seg_byte_size >> 9); // size in sectors
 610         pr_info("Loaded %s with total size %lu bytes and capacity %lu "
 611                 "sectors\n", local_buf, seg_byte_size, seg_byte_size >> 9);
 612
 613         dev_info->save_pending = 0;
 614         dev_info->is_shared = 1;
 615         dev_info->dev.parent = dcssblk_root_dev;
 616
 617         /*
 618          *get minor, add to list
 619          */
 620         down_write(&dcssblk_devices_sem);
 621         if (dcssblk_get_segment_by_name(local_buf)) {
 622                 rc = -EEXIST;
 623                 goto release_gd;
 624         }
 625         rc = dcssblk_assign_free_minor(dev_info);
 626         if (rc)
 627                 goto release_gd;
 628         sprintf(dev_info->gd->disk_name, "dcssblk%d",
 629                 MINOR(disk_devt(dev_info->gd)));
 630         list_add_tail(&dev_info->lh, &dcssblk_devices);
 631
 632         if (!try_module_get(THIS_MODULE)) {
 633                 rc = -ENODEV;
 634                 goto dev_list_del;
 635         }
 636         /*
 637          * register the device
 638          */
 639         rc = device_register(&dev_info->dev);
 640         if (rc) {
 641                 module_put(THIS_MODULE);
 642                 goto dev_list_del;
 643         }
 644         get_device(&dev_info->dev);
 645         rc = device_create_file(&dev_info->dev, &dev_attr_shared);
 646         if (rc)
 647                 goto unregister_dev;
 648         rc = device_create_file(&dev_info->dev, &dev_attr_save);
 649         if (rc)
 650                 goto unregister_dev;
 651         rc = device_create_file(&dev_info->dev, &dev_attr_seglist);
 652         if (rc)
 653                 goto unregister_dev;
 654
 655         add_disk(dev_info->gd);
 656
 657         switch (dev_info->segment_type) {
 658                 case SEG_TYPE_SR:
 659                 case SEG_TYPE_ER:
 660                 case SEG_TYPE_SC:
 661                         set_disk_ro(dev_info->gd,1);
 662                         break;
 663                 default:
 664                         set_disk_ro(dev_info->gd,0);
 665                         break;
 666         }
 667         up_write(&dcssblk_devices_sem);
 668         rc = count;
 669         goto out;
 670
 671 unregister_dev:
 672         list_del(&dev_info->lh);
 673         blk_cleanup_queue(dev_info->dcssblk_queue);
 674         dev_info->gd->queue = NULL;
 675         put_disk(dev_info->gd);
 676         device_unregister(&dev_info->dev);
 677         list_for_each_entry(seg_info, &dev_info->seg_list, lh) {
 678                 segment_unload(seg_info->segment_name);
 679         }
 680         put_device(&dev_info->dev);
 681         up_write(&dcssblk_devices_sem);
 682         goto out;
 683 dev_list_del:
 684         list_del(&dev_info->lh);
 685 release_gd:
 686         blk_cleanup_queue(dev_info->dcssblk_queue);
 687         dev_info->gd->queue = NULL;
 688         put_disk(dev_info->gd);
 689         up_write(&dcssblk_devices_sem);
 690 seg_list_del:
 691         if (dev_info == NULL)
 692                 goto out;
 693         list_for_each_entry_safe(seg_info, temp, &dev_info->seg_list, lh) {
 694                 list_del(&seg_info->lh);
 695                 segment_unload(seg_info->segment_name);
 696                 kfree(seg_info);
 697         }
 698         kfree(dev_info);
 699 out:
 700         kfree(local_buf);
 701 out_nobuf:
 702         return rc;
 703 }
 704
 705 /*
 706  * device attribute for removing devices
 707  */
 708 static ssize_t
 709 dcssblk_remove_store(struct device *dev, struct device_attribute *attr, const char *buf, size_t count)
 710 {
 711         struct dcssblk_dev_info *dev_info;
 712         struct segment_info *entry;
 713         int rc, i;
 714         char *local_buf;
 715
 716         if (dev != dcssblk_root_dev) {
 717                 return -EINVAL;
 718         }
 719         local_buf = kmalloc(count + 1, GFP_KERNEL);
 720         if (local_buf == NULL) {
 721                 return -ENOMEM;
 722         }
 723         /*
 724          * parse input
 725          */
 726         for (i = 0; ((*(buf+i)!='\0') && (*(buf+i)!='\n') && i < count); i++) {
 727                 local_buf[i] = toupper(buf[i]);
 728         }
 729         local_buf[i] = '\0';
 730         if ((i == 0) || (i > 8)) {
 731                 rc = -ENAMETOOLONG;
 732                 goto out_buf;
 733         }
 734
 735         down_write(&dcssblk_devices_sem);
 736         dev_info = dcssblk_get_device_by_name(local_buf);
 737         if (dev_info == NULL) {
 738                 up_write(&dcssblk_devices_sem);
 739                 pr_warning("Device %s cannot be removed because it is not a "
 740                            "known device\n", local_buf);
 741                 rc = -ENODEV;
 742                 goto out_buf;
 743         }
 744         if (atomic_read(&dev_info->use_count) != 0) {
 745                 up_write(&dcssblk_devices_sem);
 746                 pr_warning("Device %s cannot be removed while it is in "
 747                            "use\n", local_buf);
 748                 rc = -EBUSY;
 749                 goto out_buf;
 750         }
 751
 752         list_del(&dev_info->lh);
 753         del_gendisk(dev_info->gd);
 754         blk_cleanup_queue(dev_info->dcssblk_queue);
 755         dev_info->gd->queue = NULL;
 756         put_disk(dev_info->gd);
 757         device_unregister(&dev_info->dev);
 758
 759         /* unload all related segments */
 760         list_for_each_entry(entry, &dev_info->seg_list, lh)
 761                 segment_unload(entry->segment_name);
 762
 763         put_device(&dev_info->dev);
 764         up_write(&dcssblk_devices_sem);
 765
 766         rc = count;
 767 out_buf:
 768         kfree(local_buf);
 769         return rc;
 770 }
 771
 772 static int
 773 dcssblk_open(struct block_device *bdev, fmode_t mode)
 774 {
 775         struct dcssblk_dev_info *dev_info;
 776         int rc;
 777
 778         dev_info = bdev->bd_disk->private_data;
 779         if (NULL == dev_info) {
 780                 rc = -ENODEV;
 781                 goto out;
 782         }
 783         atomic_inc(&dev_info->use_count);
 784         bdev->bd_block_size = 4096;
 785         rc = 0;
 786 out:
 787         return rc;
 788 }
 789
 790 static int
 791 dcssblk_release(struct gendisk *disk, fmode_t mode)
 792 {
 793         struct dcssblk_dev_info *dev_info = disk->private_data;
 794         struct segment_info *entry;
 795         int rc;
 796
 797         if (!dev_info) {
 798                 rc = -ENODEV;
 799                 goto out;
 800         }
 801         down_write(&dcssblk_devices_sem);
 802         if (atomic_dec_and_test(&dev_info->use_count)
 803             && (dev_info->save_pending)) {
 804                 pr_info("Device %s has become idle and is being saved "
 805                         "now\n", dev_info->segment_name);
 806                 list_for_each_entry(entry, &dev_info->seg_list, lh) {
 807                         segment_save(entry->segment_name);
 808                 }
 809                 dev_info->save_pending = 0;
 810         }
 811         up_write(&dcssblk_devices_sem);
 812         rc = 0;
 813 out:
 814         return rc;
 815 }
 816
 817 static int
 818 dcssblk_make_request(struct request_queue *q, struct bio *bio)
 819 {
 820         struct dcssblk_dev_info *dev_info;
 821         struct bio_vec *bvec;
 822         unsigned long index;
 823         unsigned long page_addr;
 824         unsigned long source_addr;
 825         unsigned long bytes_done;
 826         int i;
 827
 828         bytes_done = 0;
 829         dev_info = bio->bi_bdev->bd_disk->private_data;
 830         if (dev_info == NULL)
 831                 goto fail;
 832         if ((bio->bi_sector & 7) != 0 || (bio->bi_size & 4095) != 0)
 833                 /* Request is not page-aligned. */
 834                 goto fail;
 835         if (((bio->bi_size >> 9) + bio->bi_sector)
 836                         > get_capacity(bio->bi_bdev->bd_disk)) {
 837                 /* Request beyond end of DCSS segment. */
 838                 goto fail;
 839         }
 840         /* verify data transfer direction */
 841         if (dev_info->is_shared) {
 842                 switch (dev_info->segment_type) {
 843                 case SEG_TYPE_SR:
 844                 case SEG_TYPE_ER:
 845                 case SEG_TYPE_SC:
 846                         /* cannot write to these segments */
 847                         if (bio_data_dir(bio) == WRITE) {
 848                                 pr_warning("Writing to %s failed because it "
 849                                            "is a read-only device\n",
 850                                            dev_name(&dev_info->dev));
 851                                 goto fail;
 852                         }
 853                 }
 854         }
 855
 856         index = (bio->bi_sector >> 3);
 857         bio_for_each_segment(bvec, bio, i) {
 858                 page_addr = (unsigned long)
 859                         page_address(bvec->bv_page) + bvec->bv_offset;
 860                 source_addr = dev_info->start + (index<<12) + bytes_done;
 861                 if (unlikely((page_addr & 4095) != 0) || (bvec->bv_len & 4095) != 0)
 862                         // More paranoia.
 863                         goto fail;
 864                 if (bio_data_dir(bio) == READ) {
 865                         memcpy((void*)page_addr, (void*)source_addr,
 866                                 bvec->bv_len);
 867                 } else {
 868                         memcpy((void*)source_addr, (void*)page_addr,
 869                                 bvec->bv_len);
 870                 }
 871                 bytes_done += bvec->bv_len;
 872         }
 873         bio_endio(bio, 0);
 874         return 0;
 875 fail:
 876         bio_io_error(bio);
 877         return 0;
 878 }
 879
 880 static int
 881 dcssblk_direct_access (struct block_device *bdev, sector_t secnum,
 882                         void **kaddr, unsigned long *pfn)
 883 {
 884         struct dcssblk_dev_info *dev_info;
 885         unsigned long pgoff;
 886
 887         dev_info = bdev->bd_disk->private_data;
 888         if (!dev_info)
 889                 return -ENODEV;
 890         if (secnum % (PAGE_SIZE/512))
 891                 return -EINVAL;
 892         pgoff = secnum / (PAGE_SIZE / 512);
 893         if ((pgoff+1)*PAGE_SIZE-1 > dev_info->end - dev_info->start)
 894                 return -ERANGE;
 895         *kaddr = (void *) (dev_info->start+pgoff*PAGE_SIZE);
 896         *pfn = virt_to_phys(*kaddr) >> PAGE_SHIFT;
 897
 898         return 0;
 899 }
 900
 901 static void
 902 dcssblk_check_params(void)
 903 {
 904         int rc, i, j, k;
 905         char buf[DCSSBLK_PARM_LEN + 1];
 906         struct dcssblk_dev_info *dev_info;
 907
 908         for (i = 0; (i < DCSSBLK_PARM_LEN) && (dcssblk_segments[i] != '\0');
 909              i++) {
 910                 for (j = i; (dcssblk_segments[j] != ',')  &&
 911                             (dcssblk_segments[j] != '\0') &&
 912                             (dcssblk_segments[j] != '(')  &&
 913                             (j < DCSSBLK_PARM_LEN); j++)
 914                 {
 915                         buf[j-i] = dcssblk_segments[j];
 916                 }
 917                 buf[j-i] = '\0';
 918                 rc = dcssblk_add_store(dcssblk_root_dev, NULL, buf, j-i);
 919                 if ((rc >= 0) && (dcssblk_segments[j] == '(')) {
 920                         for (k = 0; (buf[k] != ':') && (buf[k] != '\0'); k++)
 921                                 buf[k] = toupper(buf[k]);
 922                         buf[k] = '\0';
 923                         if (!strncmp(&dcssblk_segments[j], "(local)", 7)) {
 924                                 down_read(&dcssblk_devices_sem);
 925                                 dev_info = dcssblk_get_device_by_name(buf);
 926                                 up_read(&dcssblk_devices_sem);
 927                                 if (dev_info)
 928                                         dcssblk_shared_store(&dev_info->dev,
 929                                                              NULL, "0\n", 2);
 930                         }
 931                 }
 932                 while ((dcssblk_segments[j] != ',') &&
 933                        (dcssblk_segments[j] != '\0'))
 934                 {
 935                         j++;
 936                 }
 937                 if (dcssblk_segments[j] == '\0')
 938                         break;
 939                 i = j;
 940         }
 941 }
 942
 943 /*
 944  * The init/exit functions.
 945  */
 946 static void __exit
 947 dcssblk_exit(void)
 948 {
 949         s390_root_dev_unregister(dcssblk_root_dev);
 950         unregister_blkdev(dcssblk_major, DCSSBLK_NAME);
 951 }
 952
 953 static int __init
 954 dcssblk_init(void)
 955 {
 956         int rc;
 957
 958         dcssblk_root_dev = s390_root_dev_register("dcssblk");
 959         if (IS_ERR(dcssblk_root_dev))
 960                 return PTR_ERR(dcssblk_root_dev);
 961         rc = device_create_file(dcssblk_root_dev, &dev_attr_add);
 962         if (rc) {
 963                 s390_root_dev_unregister(dcssblk_root_dev);
 964                 return rc;
 965         }
 966         rc = device_create_file(dcssblk_root_dev, &dev_attr_remove);
 967         if (rc) {
 968                 s390_root_dev_unregister(dcssblk_root_dev);
 969                 return rc;
 970         }
 971         rc = register_blkdev(0, DCSSBLK_NAME);
 972         if (rc < 0) {
 973                 s390_root_dev_unregister(dcssblk_root_dev);
 974                 return rc;
 975         }
 976         dcssblk_major = rc;
 977         init_rwsem(&dcssblk_devices_sem);
 978
 979         dcssblk_check_params();
 980
 981         return 0;
 982 }
 983
 984 module_init(dcssblk_init);
 985 module_exit(dcssblk_exit);
 986
 987 module_param_string(segments, dcssblk_segments, DCSSBLK_PARM_LEN, 0444);
 988 MODULE_PARM_DESC(segments, "Name of DCSS segment(s) to be loaded, "
 989                  "comma-separated list, names in each set separated "
 990                  "by commas are separated by colons, each set contains "
 991                  "names of contiguous segments and each name max. 8 chars.\n"
 992                  "Adding \"(local)\" to the end of each set equals echoing 0 "
 993                  "to /sys/devices/dcssblk/<device name>/shared after loading "
 994                  "the contiguous segments - \n"
 995                  "e.g. segments=\"mydcss1,mydcss2:mydcss3,mydcss4(local)\"");
 996
 997 MODULE_LICENSE("GPL");