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 <linux/completion.h>
  18 #include <linux/interrupt.h>
  19 #include <linux/platform_device.h>
  20 #include <asm/extmem.h>
  21 #include <asm/io.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 void dcssblk_release(struct gendisk *disk, fmode_t mode);
  30 static void dcssblk_make_request(struct request_queue *q, struct bio *bio);
  31 static long dcssblk_direct_access(struct block_device *bdev, sector_t secnum,
  32                                  void **kaddr, unsigned long *pfn, long size);
  33
  34 static char dcssblk_segments[DCSSBLK_PARM_LEN] = "\0";
  35
  36 static int dcssblk_major;
  37 static const 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
  73 static DEVICE_ATTR(add, S_IWUSR, NULL, dcssblk_add_store);
  74 static DEVICE_ATTR(remove, S_IWUSR, NULL, dcssblk_remove_store);
  75
  76 static struct device *dcssblk_root_dev;
  77
  78 static LIST_HEAD(dcssblk_devices);
  79 static struct rw_semaphore dcssblk_devices_sem;
  80
  81 /*
  82  * release function for segment device.
  83  */
  84 static void
  85 dcssblk_release_segment(struct device *dev)
  86 {
  87         struct dcssblk_dev_info *dev_info;
  88         struct segment_info *entry, *temp;
  89
  90         dev_info = container_of(dev, struct dcssblk_dev_info, dev);
  91         list_for_each_entry_safe(entry, temp, &dev_info->seg_list, lh) {
  92                 list_del(&entry->lh);
  93                 kfree(entry);
  94         }
  95         kfree(dev_info);
  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 /*
 146  * get the struct segment_info from seg_list
 147  * for the given name.
 148  * down_read(&dcssblk_devices_sem) must be held.
 149  */
 150 static struct segment_info *
 151 dcssblk_get_segment_by_name(char *name)
 152 {
 153         struct dcssblk_dev_info *dev_info;
 154         struct segment_info *entry;
 155
 156         list_for_each_entry(dev_info, &dcssblk_devices, lh) {
 157                 list_for_each_entry(entry, &dev_info->seg_list, lh) {
 158                         if (!strcmp(name, entry->segment_name))
 159                                 return entry;
 160                 }
 161         }
 162         return NULL;
 163 }
 164
 165 /*
 166  * get the highest address of the multi-segment block.
 167  */
 168 static unsigned long
 169 dcssblk_find_highest_addr(struct dcssblk_dev_info *dev_info)
 170 {
 171         unsigned long highest_addr;
 172         struct segment_info *entry;
 173
 174         highest_addr = 0;
 175         list_for_each_entry(entry, &dev_info->seg_list, lh) {
 176                 if (highest_addr < entry->end)
 177                         highest_addr = entry->end;
 178         }
 179         return highest_addr;
 180 }
 181
 182 /*
 183  * get the lowest address of the multi-segment block.
 184  */
 185 static unsigned long
 186 dcssblk_find_lowest_addr(struct dcssblk_dev_info *dev_info)
 187 {
 188         int set_first;
 189         unsigned long lowest_addr;
 190         struct segment_info *entry;
 191
 192         set_first = 0;
 193         lowest_addr = 0;
 194         list_for_each_entry(entry, &dev_info->seg_list, lh) {
 195                 if (set_first == 0) {
 196                         lowest_addr = entry->start;
 197                         set_first = 1;
 198                 } else {
 199                         if (lowest_addr > entry->start)
 200                                 lowest_addr = entry->start;
 201                 }
 202         }
 203         return lowest_addr;
 204 }
 205
 206 /*
 207  * Check continuity of segments.
 208  */
 209 static int
 210 dcssblk_is_continuous(struct dcssblk_dev_info *dev_info)
 211 {
 212         int i, j, rc;
 213         struct segment_info *sort_list, *entry, temp;
 214
 215         if (dev_info->num_of_segments <= 1)
 216                 return 0;
 217
 218         sort_list = kzalloc(
 219                         sizeof(struct segment_info) * dev_info->num_of_segments,
 220                         GFP_KERNEL);
 221         if (sort_list == NULL)
 222                 return -ENOMEM;
 223         i = 0;
 224         list_for_each_entry(entry, &dev_info->seg_list, lh) {
 225                 memcpy(&sort_list[i], entry, sizeof(struct segment_info));
 226                 i++;
 227         }
 228
 229         /* sort segments */
 230         for (i = 0; i < dev_info->num_of_segments; i++)
 231                 for (j = 0; j < dev_info->num_of_segments; j++)
 232                         if (sort_list[j].start > sort_list[i].start) {
 233                                 memcpy(&temp, &sort_list[i],
 234                                         sizeof(struct segment_info));
 235                                 memcpy(&sort_list[i], &sort_list[j],
 236                                         sizeof(struct segment_info));
 237                                 memcpy(&sort_list[j], &temp,
 238                                         sizeof(struct segment_info));
 239                         }
 240
 241         /* check continuity */
 242         for (i = 0; i < dev_info->num_of_segments - 1; i++) {
 243                 if ((sort_list[i].end + 1) != sort_list[i+1].start) {
 244                         pr_err("Adjacent DCSSs %s and %s are not "
 245                                "contiguous\n", sort_list[i].segment_name,
 246                                sort_list[i+1].segment_name);
 247                         rc = -EINVAL;
 248                         goto out;
 249                 }
 250                 /* EN and EW are allowed in a block device */
 251                 if (sort_list[i].segment_type != sort_list[i+1].segment_type) {
 252                         if (!(sort_list[i].segment_type & SEGMENT_EXCLUSIVE) ||
 253                                 (sort_list[i].segment_type == SEG_TYPE_ER) ||
 254                                 !(sort_list[i+1].segment_type &
 255                                 SEGMENT_EXCLUSIVE) ||
 256                                 (sort_list[i+1].segment_type == SEG_TYPE_ER)) {
 257                                 pr_err("DCSS %s and DCSS %s have "
 258                                        "incompatible types\n",
 259                                        sort_list[i].segment_name,
 260                                        sort_list[i+1].segment_name);
 261                                 rc = -EINVAL;
 262                                 goto out;
 263                         }
 264                 }
 265         }
 266         rc = 0;
 267 out:
 268         kfree(sort_list);
 269         return rc;
 270 }
 271
 272 /*
 273  * Load a segment
 274  */
 275 static int
 276 dcssblk_load_segment(char *name, struct segment_info **seg_info)
 277 {
 278         int rc;
 279
 280         /* already loaded? */
 281         down_read(&dcssblk_devices_sem);
 282         *seg_info = dcssblk_get_segment_by_name(name);
 283         up_read(&dcssblk_devices_sem);
 284         if (*seg_info != NULL)
 285                 return -EEXIST;
 286
 287         /* get a struct segment_info */
 288         *seg_info = kzalloc(sizeof(struct segment_info), GFP_KERNEL);
 289         if (*seg_info == NULL)
 290                 return -ENOMEM;
 291
 292         strcpy((*seg_info)->segment_name, name);
 293
 294         /* load the segment */
 295         rc = segment_load(name, SEGMENT_SHARED,
 296                         &(*seg_info)->start, &(*seg_info)->end);
 297         if (rc < 0) {
 298                 segment_warning(rc, (*seg_info)->segment_name);
 299                 kfree(*seg_info);
 300         } else {
 301                 INIT_LIST_HEAD(&(*seg_info)->lh);
 302                 (*seg_info)->segment_type = rc;
 303         }
 304         return rc;
 305 }
 306
 307 /*
 308  * device attribute for switching shared/nonshared (exclusive)
 309  * operation (show + store)
 310  */
 311 static ssize_t
 312 dcssblk_shared_show(struct device *dev, struct device_attribute *attr, char *buf)
 313 {
 314         struct dcssblk_dev_info *dev_info;
 315
 316         dev_info = container_of(dev, struct dcssblk_dev_info, dev);
 317         return sprintf(buf, dev_info->is_shared ? "1\n" : "0\n");
 318 }
 319
 320 static ssize_t
 321 dcssblk_shared_store(struct device *dev, struct device_attribute *attr, const char *inbuf, size_t count)
 322 {
 323         struct dcssblk_dev_info *dev_info;
 324         struct segment_info *entry, *temp;
 325         int rc;
 326
 327         if ((count > 1) && (inbuf[1] != '\n') && (inbuf[1] != '\0'))
 328                 return -EINVAL;
 329         down_write(&dcssblk_devices_sem);
 330         dev_info = container_of(dev, struct dcssblk_dev_info, dev);
 331         if (atomic_read(&dev_info->use_count)) {
 332                 rc = -EBUSY;
 333                 goto out;
 334         }
 335         if (inbuf[0] == '1') {
 336                 /* reload segments in shared mode */
 337                 list_for_each_entry(entry, &dev_info->seg_list, lh) {
 338                         rc = segment_modify_shared(entry->segment_name,
 339                                                 SEGMENT_SHARED);
 340                         if (rc < 0) {
 341                                 BUG_ON(rc == -EINVAL);
 342                                 if (rc != -EAGAIN)
 343                                         goto removeseg;
 344                         }
 345                 }
 346                 dev_info->is_shared = 1;
 347                 switch (dev_info->segment_type) {
 348                 case SEG_TYPE_SR:
 349                 case SEG_TYPE_ER:
 350                 case SEG_TYPE_SC:
 351                         set_disk_ro(dev_info->gd, 1);
 352                 }
 353         } else if (inbuf[0] == '0') {
 354                 /* reload segments in exclusive mode */
 355                 if (dev_info->segment_type == SEG_TYPE_SC) {
 356                         pr_err("DCSS %s is of type SC and cannot be "
 357                                "loaded as exclusive-writable\n",
 358                                dev_info->segment_name);
 359                         rc = -EINVAL;
 360                         goto out;
 361                 }
 362                 list_for_each_entry(entry, &dev_info->seg_list, lh) {
 363                         rc = segment_modify_shared(entry->segment_name,
 364                                                    SEGMENT_EXCLUSIVE);
 365                         if (rc < 0) {
 366                                 BUG_ON(rc == -EINVAL);
 367                                 if (rc != -EAGAIN)
 368                                         goto removeseg;
 369                         }
 370                 }
 371                 dev_info->is_shared = 0;
 372                 set_disk_ro(dev_info->gd, 0);
 373         } else {
 374                 rc = -EINVAL;
 375                 goto out;
 376         }
 377         rc = count;
 378         goto out;
 379
 380 removeseg:
 381         pr_err("DCSS device %s is removed after a failed access mode "
 382                "change\n", dev_info->segment_name);
 383         temp = entry;
 384         list_for_each_entry(entry, &dev_info->seg_list, lh) {
 385                 if (entry != temp)
 386                         segment_unload(entry->segment_name);
 387         }
 388         list_del(&dev_info->lh);
 389
 390         del_gendisk(dev_info->gd);
 391         blk_cleanup_queue(dev_info->dcssblk_queue);
 392         dev_info->gd->queue = NULL;
 393         put_disk(dev_info->gd);
 394         up_write(&dcssblk_devices_sem);
 395
 396         if (device_remove_file_self(dev, attr)) {
 397                 device_unregister(dev);
 398                 put_device(dev);
 399         }
 400         return rc;
 401 out:
 402         up_write(&dcssblk_devices_sem);
 403         return rc;
 404 }
 405 static DEVICE_ATTR(shared, S_IWUSR | S_IRUSR, dcssblk_shared_show,
 406                    dcssblk_shared_store);
 407
 408 /*
 409  * device attribute for save operation on current copy
 410  * of the segment. If the segment is busy, saving will
 411  * become pending until it gets released, which can be
 412  * undone by storing a non-true value to this entry.
 413  * (show + store)
 414  */
 415 static ssize_t
 416 dcssblk_save_show(struct device *dev, struct device_attribute *attr, char *buf)
 417 {
 418         struct dcssblk_dev_info *dev_info;
 419
 420         dev_info = container_of(dev, struct dcssblk_dev_info, dev);
 421         return sprintf(buf, dev_info->save_pending ? "1\n" : "0\n");
 422 }
 423
 424 static ssize_t
 425 dcssblk_save_store(struct device *dev, struct device_attribute *attr, const char *inbuf, size_t count)
 426 {
 427         struct dcssblk_dev_info *dev_info;
 428         struct segment_info *entry;
 429
 430         if ((count > 1) && (inbuf[1] != '\n') && (inbuf[1] != '\0'))
 431                 return -EINVAL;
 432         dev_info = container_of(dev, struct dcssblk_dev_info, dev);
 433
 434         down_write(&dcssblk_devices_sem);
 435         if (inbuf[0] == '1') {
 436                 if (atomic_read(&dev_info->use_count) == 0) {
 437                         // device is idle => we save immediately
 438                         pr_info("All DCSSs that map to device %s are "
 439                                 "saved\n", dev_info->segment_name);
 440                         list_for_each_entry(entry, &dev_info->seg_list, lh) {
 441                                 if (entry->segment_type == SEG_TYPE_EN ||
 442                                     entry->segment_type == SEG_TYPE_SN)
 443                                         pr_warn("DCSS %s is of type SN or EN"
 444                                                 " and cannot be saved\n",
 445                                                 entry->segment_name);
 446                                 else
 447                                         segment_save(entry->segment_name);
 448                         }
 449                 }  else {
 450                         // device is busy => we save it when it becomes
 451                         // idle in dcssblk_release
 452                         pr_info("Device %s is in use, its DCSSs will be "
 453                                 "saved when it becomes idle\n",
 454                                 dev_info->segment_name);
 455                         dev_info->save_pending = 1;
 456                 }
 457         } else if (inbuf[0] == '0') {
 458                 if (dev_info->save_pending) {
 459                         // device is busy & the user wants to undo his save
 460                         // request
 461                         dev_info->save_pending = 0;
 462                         pr_info("A pending save request for device %s "
 463                                 "has been canceled\n",
 464                                 dev_info->segment_name);
 465                 }
 466         } else {
 467                 up_write(&dcssblk_devices_sem);
 468                 return -EINVAL;
 469         }
 470         up_write(&dcssblk_devices_sem);
 471         return count;
 472 }
 473 static DEVICE_ATTR(save, S_IWUSR | S_IRUSR, dcssblk_save_show,
 474                    dcssblk_save_store);
 475
 476 /*
 477  * device attribute for showing all segments in a device
 478  */
 479 static ssize_t
 480 dcssblk_seglist_show(struct device *dev, struct device_attribute *attr,
 481                 char *buf)
 482 {
 483         int i;
 484
 485         struct dcssblk_dev_info *dev_info;
 486         struct segment_info *entry;
 487
 488         down_read(&dcssblk_devices_sem);
 489         dev_info = container_of(dev, struct dcssblk_dev_info, dev);
 490         i = 0;
 491         buf[0] = '\0';
 492         list_for_each_entry(entry, &dev_info->seg_list, lh) {
 493                 strcpy(&buf[i], entry->segment_name);
 494                 i += strlen(entry->segment_name);
 495                 buf[i] = '\n';
 496                 i++;
 497         }
 498         up_read(&dcssblk_devices_sem);
 499         return i;
 500 }
 501 static DEVICE_ATTR(seglist, S_IRUSR, dcssblk_seglist_show, NULL);
 502
 503 static struct attribute *dcssblk_dev_attrs[] = {
 504         &dev_attr_shared.attr,
 505         &dev_attr_save.attr,
 506         &dev_attr_seglist.attr,
 507         NULL,
 508 };
 509 static struct attribute_group dcssblk_dev_attr_group = {
 510         .attrs = dcssblk_dev_attrs,
 511 };
 512 static const struct attribute_group *dcssblk_dev_attr_groups[] = {
 513         &dcssblk_dev_attr_group,
 514         NULL,
 515 };
 516
 517 /*
 518  * device attribute for adding devices
 519  */
 520 static ssize_t
 521 dcssblk_add_store(struct device *dev, struct device_attribute *attr, const char *buf, size_t count)
 522 {
 523         int rc, i, j, num_of_segments;
 524         struct dcssblk_dev_info *dev_info;
 525         struct segment_info *seg_info, *temp;
 526         char *local_buf;
 527         unsigned long seg_byte_size;
 528
 529         dev_info = NULL;
 530         seg_info = NULL;
 531         if (dev != dcssblk_root_dev) {
 532                 rc = -EINVAL;
 533                 goto out_nobuf;
 534         }
 535         if ((count < 1) || (buf[0] == '\0') || (buf[0] == '\n')) {
 536                 rc = -ENAMETOOLONG;
 537                 goto out_nobuf;
 538         }
 539
 540         local_buf = kmalloc(count + 1, GFP_KERNEL);
 541         if (local_buf == NULL) {
 542                 rc = -ENOMEM;
 543                 goto out_nobuf;
 544         }
 545
 546         /*
 547          * parse input
 548          */
 549         num_of_segments = 0;
 550         for (i = 0; (i < count && (buf[i] != '\0') && (buf[i] != '\n')); i++) {
 551                 for (j = i; (buf[j] != ':') &&
 552                         (buf[j] != '\0') &&
 553                         (buf[j] != '\n') &&
 554                         j < count; j++) {
 555                         local_buf[j-i] = toupper(buf[j]);
 556                 }
 557                 local_buf[j-i] = '\0';
 558                 if (((j - i) == 0) || ((j - i) > 8)) {
 559                         rc = -ENAMETOOLONG;
 560                         goto seg_list_del;
 561                 }
 562
 563                 rc = dcssblk_load_segment(local_buf, &seg_info);
 564                 if (rc < 0)
 565                         goto seg_list_del;
 566                 /*
 567                  * get a struct dcssblk_dev_info
 568                  */
 569                 if (num_of_segments == 0) {
 570                         dev_info = kzalloc(sizeof(struct dcssblk_dev_info),
 571                                         GFP_KERNEL);
 572                         if (dev_info == NULL) {
 573                                 rc = -ENOMEM;
 574                                 goto out;
 575                         }
 576                         strcpy(dev_info->segment_name, local_buf);
 577                         dev_info->segment_type = seg_info->segment_type;
 578                         INIT_LIST_HEAD(&dev_info->seg_list);
 579                 }
 580                 list_add_tail(&seg_info->lh, &dev_info->seg_list);
 581                 num_of_segments++;
 582                 i = j;
 583
 584                 if ((buf[j] == '\0') || (buf[j] == '\n'))
 585                         break;
 586         }
 587
 588         /* no trailing colon at the end of the input */
 589         if ((i > 0) && (buf[i-1] == ':')) {
 590                 rc = -ENAMETOOLONG;
 591                 goto seg_list_del;
 592         }
 593         strlcpy(local_buf, buf, i + 1);
 594         dev_info->num_of_segments = num_of_segments;
 595         rc = dcssblk_is_continuous(dev_info);
 596         if (rc < 0)
 597                 goto seg_list_del;
 598
 599         dev_info->start = dcssblk_find_lowest_addr(dev_info);
 600         dev_info->end = dcssblk_find_highest_addr(dev_info);
 601
 602         dev_set_name(&dev_info->dev, "%s", dev_info->segment_name);
 603         dev_info->dev.release = dcssblk_release_segment;
 604         dev_info->dev.groups = dcssblk_dev_attr_groups;
 605         INIT_LIST_HEAD(&dev_info->lh);
 606         dev_info->gd = alloc_disk(DCSSBLK_MINORS_PER_DISK);
 607         if (dev_info->gd == NULL) {
 608                 rc = -ENOMEM;
 609                 goto seg_list_del;
 610         }
 611         dev_info->gd->major = dcssblk_major;
 612         dev_info->gd->fops = &dcssblk_devops;
 613         dev_info->dcssblk_queue = blk_alloc_queue(GFP_KERNEL);
 614         dev_info->gd->queue = dev_info->dcssblk_queue;
 615         dev_info->gd->private_data = dev_info;
 616         dev_info->gd->driverfs_dev = &dev_info->dev;
 617         blk_queue_make_request(dev_info->dcssblk_queue, dcssblk_make_request);
 618         blk_queue_logical_block_size(dev_info->dcssblk_queue, 4096);
 619
 620         seg_byte_size = (dev_info->end - dev_info->start + 1);
 621         set_capacity(dev_info->gd, seg_byte_size >> 9); // size in sectors
 622         pr_info("Loaded %s with total size %lu bytes and capacity %lu "
 623                 "sectors\n", local_buf, seg_byte_size, seg_byte_size >> 9);
 624
 625         dev_info->save_pending = 0;
 626         dev_info->is_shared = 1;
 627         dev_info->dev.parent = dcssblk_root_dev;
 628
 629         /*
 630          *get minor, add to list
 631          */
 632         down_write(&dcssblk_devices_sem);
 633         if (dcssblk_get_segment_by_name(local_buf)) {
 634                 rc = -EEXIST;
 635                 goto release_gd;
 636         }
 637         rc = dcssblk_assign_free_minor(dev_info);
 638         if (rc)
 639                 goto release_gd;
 640         sprintf(dev_info->gd->disk_name, "dcssblk%d",
 641                 dev_info->gd->first_minor);
 642         list_add_tail(&dev_info->lh, &dcssblk_devices);
 643
 644         if (!try_module_get(THIS_MODULE)) {
 645                 rc = -ENODEV;
 646                 goto dev_list_del;
 647         }
 648         /*
 649          * register the device
 650          */
 651         rc = device_register(&dev_info->dev);
 652         if (rc)
 653                 goto put_dev;
 654
 655         get_device(&dev_info->dev);
 656         add_disk(dev_info->gd);
 657
 658         switch (dev_info->segment_type) {
 659                 case SEG_TYPE_SR:
 660                 case SEG_TYPE_ER:
 661                 case SEG_TYPE_SC:
 662                         set_disk_ro(dev_info->gd,1);
 663                         break;
 664                 default:
 665                         set_disk_ro(dev_info->gd,0);
 666                         break;
 667         }
 668         up_write(&dcssblk_devices_sem);
 669         rc = count;
 670         goto out;
 671
 672 put_dev:
 673         list_del(&dev_info->lh);
 674         blk_cleanup_queue(dev_info->dcssblk_queue);
 675         dev_info->gd->queue = NULL;
 676         put_disk(dev_info->gd);
 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 void
 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
 796         if (!dev_info) {
 797                 WARN_ON(1);
 798                 return;
 799         }
 800         down_write(&dcssblk_devices_sem);
 801         if (atomic_dec_and_test(&dev_info->use_count)
 802             && (dev_info->save_pending)) {
 803                 pr_info("Device %s has become idle and is being saved "
 804                         "now\n", dev_info->segment_name);
 805                 list_for_each_entry(entry, &dev_info->seg_list, lh) {
 806                         if (entry->segment_type == SEG_TYPE_EN ||
 807                             entry->segment_type == SEG_TYPE_SN)
 808                                 pr_warn("DCSS %s is of type SN or EN and cannot"
 809                                         " be saved\n", entry->segment_name);
 810                         else
 811                                 segment_save(entry->segment_name);
 812                 }
 813                 dev_info->save_pending = 0;
 814         }
 815         up_write(&dcssblk_devices_sem);
 816 }
 817
 818 static void
 819 dcssblk_make_request(struct request_queue *q, struct bio *bio)
 820 {
 821         struct dcssblk_dev_info *dev_info;
 822         struct bio_vec bvec;
 823         struct bvec_iter iter;
 824         unsigned long index;
 825         unsigned long page_addr;
 826         unsigned long source_addr;
 827         unsigned long bytes_done;
 828
 829         bytes_done = 0;
 830         dev_info = bio->bi_bdev->bd_disk->private_data;
 831         if (dev_info == NULL)
 832                 goto fail;
 833         if ((bio->bi_iter.bi_sector & 7) != 0 ||
 834             (bio->bi_iter.bi_size & 4095) != 0)
 835                 /* Request is not page-aligned. */
 836                 goto fail;
 837         if (bio_end_sector(bio) > get_capacity(bio->bi_bdev->bd_disk)) {
 838                 /* Request beyond end of DCSS segment. */
 839                 goto fail;
 840         }
 841         /* verify data transfer direction */
 842         if (dev_info->is_shared) {
 843                 switch (dev_info->segment_type) {
 844                 case SEG_TYPE_SR:
 845                 case SEG_TYPE_ER:
 846                 case SEG_TYPE_SC:
 847                         /* cannot write to these segments */
 848                         if (bio_data_dir(bio) == WRITE) {
 849                                 pr_warning("Writing to %s failed because it "
 850                                            "is a read-only device\n",
 851                                            dev_name(&dev_info->dev));
 852                                 goto fail;
 853                         }
 854                 }
 855         }
 856
 857         index = (bio->bi_iter.bi_sector >> 3);
 858         bio_for_each_segment(bvec, bio, iter) {
 859                 page_addr = (unsigned long)
 860                         page_address(bvec.bv_page) + bvec.bv_offset;
 861                 source_addr = dev_info->start + (index<<12) + bytes_done;
 862                 if (unlikely((page_addr & 4095) != 0) || (bvec.bv_len & 4095) != 0)
 863                         // More paranoia.
 864                         goto fail;
 865                 if (bio_data_dir(bio) == READ) {
 866                         memcpy((void*)page_addr, (void*)source_addr,
 867                                 bvec.bv_len);
 868                 } else {
 869                         memcpy((void*)source_addr, (void*)page_addr,
 870                                 bvec.bv_len);
 871                 }
 872                 bytes_done += bvec.bv_len;
 873         }
 874         bio_endio(bio, 0);
 875         return;
 876 fail:
 877         bio_io_error(bio);
 878 }
 879
 880 static long
 881 dcssblk_direct_access (struct block_device *bdev, sector_t secnum,
 882                         void **kaddr, unsigned long *pfn, long size)
 883 {
 884         struct dcssblk_dev_info *dev_info;
 885         unsigned long offset, dev_sz;
 886
 887         dev_info = bdev->bd_disk->private_data;
 888         if (!dev_info)
 889                 return -ENODEV;
 890         dev_sz = dev_info->end - dev_info->start;
 891         offset = secnum * 512;
 892         *kaddr = (void *) (dev_info->start + offset);
 893         *pfn = virt_to_phys(*kaddr) >> PAGE_SHIFT;
 894
 895         return dev_sz - offset;
 896 }
 897
 898 static void
 899 dcssblk_check_params(void)
 900 {
 901         int rc, i, j, k;
 902         char buf[DCSSBLK_PARM_LEN + 1];
 903         struct dcssblk_dev_info *dev_info;
 904
 905         for (i = 0; (i < DCSSBLK_PARM_LEN) && (dcssblk_segments[i] != '\0');
 906              i++) {
 907                 for (j = i; (dcssblk_segments[j] != ',')  &&
 908                             (dcssblk_segments[j] != '\0') &&
 909                             (dcssblk_segments[j] != '(')  &&
 910                             (j < DCSSBLK_PARM_LEN); j++)
 911                 {
 912                         buf[j-i] = dcssblk_segments[j];
 913                 }
 914                 buf[j-i] = '\0';
 915                 rc = dcssblk_add_store(dcssblk_root_dev, NULL, buf, j-i);
 916                 if ((rc >= 0) && (dcssblk_segments[j] == '(')) {
 917                         for (k = 0; (buf[k] != ':') && (buf[k] != '\0'); k++)
 918                                 buf[k] = toupper(buf[k]);
 919                         buf[k] = '\0';
 920                         if (!strncmp(&dcssblk_segments[j], "(local)", 7)) {
 921                                 down_read(&dcssblk_devices_sem);
 922                                 dev_info = dcssblk_get_device_by_name(buf);
 923                                 up_read(&dcssblk_devices_sem);
 924                                 if (dev_info)
 925                                         dcssblk_shared_store(&dev_info->dev,
 926                                                              NULL, "0\n", 2);
 927                         }
 928                 }
 929                 while ((dcssblk_segments[j] != ',') &&
 930                        (dcssblk_segments[j] != '\0'))
 931                 {
 932                         j++;
 933                 }
 934                 if (dcssblk_segments[j] == '\0')
 935                         break;
 936                 i = j;
 937         }
 938 }
 939
 940 /*
 941  * Suspend / Resume
 942  */
 943 static int dcssblk_freeze(struct device *dev)
 944 {
 945         struct dcssblk_dev_info *dev_info;
 946         int rc = 0;
 947
 948         list_for_each_entry(dev_info, &dcssblk_devices, lh) {
 949                 switch (dev_info->segment_type) {
 950                         case SEG_TYPE_SR:
 951                         case SEG_TYPE_ER:
 952                         case SEG_TYPE_SC:
 953                                 if (!dev_info->is_shared)
 954                                         rc = -EINVAL;
 955                                 break;
 956                         default:
 957                                 rc = -EINVAL;
 958                                 break;
 959                 }
 960                 if (rc)
 961                         break;
 962         }
 963         if (rc)
 964                 pr_err("Suspending the system failed because DCSS device %s "
 965                        "is writable\n",
 966                        dev_info->segment_name);
 967         return rc;
 968 }
 969
 970 static int dcssblk_restore(struct device *dev)
 971 {
 972         struct dcssblk_dev_info *dev_info;
 973         struct segment_info *entry;
 974         unsigned long start, end;
 975         int rc = 0;
 976
 977         list_for_each_entry(dev_info, &dcssblk_devices, lh) {
 978                 list_for_each_entry(entry, &dev_info->seg_list, lh) {
 979                         segment_unload(entry->segment_name);
 980                         rc = segment_load(entry->segment_name, SEGMENT_SHARED,
 981                                           &start, &end);
 982                         if (rc < 0) {
 983 // TODO in_use check ?
 984                                 segment_warning(rc, entry->segment_name);
 985                                 goto out_panic;
 986                         }
 987                         if (start != entry->start || end != entry->end) {
 988                                 pr_err("The address range of DCSS %s changed "
 989                                        "while the system was suspended\n",
 990                                        entry->segment_name);
 991                                 goto out_panic;
 992                         }
 993                 }
 994         }
 995         return 0;
 996 out_panic:
 997         panic("fatal dcssblk resume error\n");
 998 }
 999
1000 static int dcssblk_thaw(struct device *dev)
1001 {
1002         return 0;
1003 }
1004
1005 static const struct dev_pm_ops dcssblk_pm_ops = {
1006         .freeze         = dcssblk_freeze,
1007         .thaw           = dcssblk_thaw,
1008         .restore        = dcssblk_restore,
1009 };
1010
1011 static struct platform_driver dcssblk_pdrv = {
1012         .driver = {
1013                 .name   = "dcssblk",
1014                 .pm     = &dcssblk_pm_ops,
1015         },
1016 };
1017
1018 static struct platform_device *dcssblk_pdev;
1019
1020
1021 /*
1022  * The init/exit functions.
1023  */
1024 static void __exit
1025 dcssblk_exit(void)
1026 {
1027         platform_device_unregister(dcssblk_pdev);
1028         platform_driver_unregister(&dcssblk_pdrv);
1029         root_device_unregister(dcssblk_root_dev);
1030         unregister_blkdev(dcssblk_major, DCSSBLK_NAME);
1031 }
1032
1033 static int __init
1034 dcssblk_init(void)
1035 {
1036         int rc;
1037
1038         rc = platform_driver_register(&dcssblk_pdrv);
1039         if (rc)
1040                 return rc;
1041
1042         dcssblk_pdev = platform_device_register_simple("dcssblk", -1, NULL,
1043                                                         0);
1044         if (IS_ERR(dcssblk_pdev)) {
1045                 rc = PTR_ERR(dcssblk_pdev);
1046                 goto out_pdrv;
1047         }
1048
1049         dcssblk_root_dev = root_device_register("dcssblk");
1050         if (IS_ERR(dcssblk_root_dev)) {
1051                 rc = PTR_ERR(dcssblk_root_dev);
1052                 goto out_pdev;
1053         }
1054         rc = device_create_file(dcssblk_root_dev, &dev_attr_add);
1055         if (rc)
1056                 goto out_root;
1057         rc = device_create_file(dcssblk_root_dev, &dev_attr_remove);
1058         if (rc)
1059                 goto out_root;
1060         rc = register_blkdev(0, DCSSBLK_NAME);
1061         if (rc < 0)
1062                 goto out_root;
1063         dcssblk_major = rc;
1064         init_rwsem(&dcssblk_devices_sem);
1065
1066         dcssblk_check_params();
1067         return 0;
1068
1069 out_root:
1070         root_device_unregister(dcssblk_root_dev);
1071 out_pdev:
1072         platform_device_unregister(dcssblk_pdev);
1073 out_pdrv:
1074         platform_driver_unregister(&dcssblk_pdrv);
1075         return rc;
1076 }
1077
1078 module_init(dcssblk_init);
1079 module_exit(dcssblk_exit);
1080
1081 module_param_string(segments, dcssblk_segments, DCSSBLK_PARM_LEN, 0444);
1082 MODULE_PARM_DESC(segments, "Name of DCSS segment(s) to be loaded, "
1083                  "comma-separated list, names in each set separated "
1084                  "by commas are separated by colons, each set contains "
1085                  "names of contiguous segments and each name max. 8 chars.\n"
1086                  "Adding \"(local)\" to the end of each set equals echoing 0 "
1087                  "to /sys/devices/dcssblk/<device name>/shared after loading "
1088                  "the contiguous segments - \n"
1089                  "e.g. segments=\"mydcss1,mydcss2:mydcss3,mydcss4(local)\"");
1090
1091 MODULE_LICENSE("GPL");