block/genhd.c

   1 /*
   2  *  gendisk handling
   3  */
   4
   5 #include <linux/config.h>
   6 #include <linux/module.h>
   7 #include <linux/fs.h>
   8 #include <linux/genhd.h>
   9 #include <linux/kernel.h>
  10 #include <linux/blkdev.h>
  11 #include <linux/init.h>
  12 #include <linux/spinlock.h>
  13 #include <linux/seq_file.h>
  14 #include <linux/slab.h>
  15 #include <linux/kmod.h>
  16 #include <linux/kobj_map.h>
  17 #include <linux/buffer_head.h>
  18
  19 #define MAX_PROBE_HASH 255      /* random */
  20
  21 static struct subsystem block_subsys;
  22
  23 static DECLARE_MUTEX(block_subsys_sem);
  24
  25 /*
  26  * Can be deleted altogether. Later.
  27  *
  28  */
  29 static struct blk_major_name {
  30         struct blk_major_name *next;
  31         int major;
  32         char name[16];
  33 } *major_names[MAX_PROBE_HASH];
  34
  35 /* index in the above - for now: assume no multimajor ranges */
  36 static inline int major_to_index(int major)
  37 {
  38         return major % MAX_PROBE_HASH;
  39 }
  40
  41 struct blkdev_info {
  42         int index;
  43         struct blk_major_name *bd;
  44 };
  45
  46 /*
  47  * iterate over a list of blkdev_info structures.  allows
  48  * the major_names array to be iterated over from outside this file
  49  * must be called with the block_subsys_sem held
  50  */
  51 void *get_next_blkdev(void *dev)
  52 {
  53         struct blkdev_info *info;
  54
  55         if (dev == NULL) {
  56                 info = kmalloc(sizeof(*info), GFP_KERNEL);
  57                 if (!info)
  58                         goto out;
  59                 info->index=0;
  60                 info->bd = major_names[info->index];
  61                 if (info->bd)
  62                         goto out;
  63         } else {
  64                 info = dev;
  65         }
  66
  67         while (info->index < ARRAY_SIZE(major_names)) {
  68                 if (info->bd)
  69                         info->bd = info->bd->next;
  70                 if (info->bd)
  71                         goto out;
  72                 /*
  73                  * No devices on this chain, move to the next
  74                  */
  75                 info->index++;
  76                 info->bd = (info->index < ARRAY_SIZE(major_names)) ?
  77                         major_names[info->index] : NULL;
  78                 if (info->bd)
  79                         goto out;
  80         }
  81
  82 out:
  83         return info;
  84 }
  85
  86 void *acquire_blkdev_list(void)
  87 {
  88         down(&block_subsys_sem);
  89         return get_next_blkdev(NULL);
  90 }
  91
  92 void release_blkdev_list(void *dev)
  93 {
  94         up(&block_subsys_sem);
  95         kfree(dev);
  96 }
  97
  98
  99 /*
 100  * Count the number of records in the blkdev_list.
 101  * must be called with the block_subsys_sem held
 102  */
 103 int count_blkdev_list(void)
 104 {
 105         struct blk_major_name *n;
 106         int i, count;
 107
 108         count = 0;
 109
 110         for (i = 0; i < ARRAY_SIZE(major_names); i++) {
 111                 for (n = major_names[i]; n; n = n->next)
 112                                 count++;
 113         }
 114
 115         return count;
 116 }
 117
 118 /*
 119  * extract the major and name values from a blkdev_info struct
 120  * passed in as a void to *dev.  Must be called with
 121  * block_subsys_sem held
 122  */
 123 int get_blkdev_info(void *dev, int *major, char **name)
 124 {
 125         struct blkdev_info *info = dev;
 126
 127         if (info->bd == NULL)
 128                 return 1;
 129
 130         *major = info->bd->major;
 131         *name = info->bd->name;
 132         return 0;
 133 }
 134
 135
 136 int register_blkdev(unsigned int major, const char *name)
 137 {
 138         struct blk_major_name **n, *p;
 139         int index, ret = 0;
 140
 141         down(&block_subsys_sem);
 142
 143         /* temporary */
 144         if (major == 0) {
 145                 for (index = ARRAY_SIZE(major_names)-1; index > 0; index--) {
 146                         if (major_names[index] == NULL)
 147                                 break;
 148                 }
 149
 150                 if (index == 0) {
 151                         printk("register_blkdev: failed to get major for %s\n",
 152                                name);
 153                         ret = -EBUSY;
 154                         goto out;
 155                 }
 156                 major = index;
 157                 ret = major;
 158         }
 159
 160         p = kmalloc(sizeof(struct blk_major_name), GFP_KERNEL);
 161         if (p == NULL) {
 162                 ret = -ENOMEM;
 163                 goto out;
 164         }
 165
 166         p->major = major;
 167         strlcpy(p->name, name, sizeof(p->name));
 168         p->next = NULL;
 169         index = major_to_index(major);
 170
 171         for (n = &major_names[index]; *n; n = &(*n)->next) {
 172                 if ((*n)->major == major)
 173                         break;
 174         }
 175         if (!*n)
 176                 *n = p;
 177         else
 178                 ret = -EBUSY;
 179
 180         if (ret < 0) {
 181                 printk("register_blkdev: cannot get major %d for %s\n",
 182                        major, name);
 183                 kfree(p);
 184         }
 185 out:
 186         up(&block_subsys_sem);
 187         return ret;
 188 }
 189
 190 EXPORT_SYMBOL(register_blkdev);
 191
 192 /* todo: make void - error printk here */
 193 int unregister_blkdev(unsigned int major, const char *name)
 194 {
 195         struct blk_major_name **n;
 196         struct blk_major_name *p = NULL;
 197         int index = major_to_index(major);
 198         int ret = 0;
 199
 200         down(&block_subsys_sem);
 201         for (n = &major_names[index]; *n; n = &(*n)->next)
 202                 if ((*n)->major == major)
 203                         break;
 204         if (!*n || strcmp((*n)->name, name))
 205                 ret = -EINVAL;
 206         else {
 207                 p = *n;
 208                 *n = p->next;
 209         }
 210         up(&block_subsys_sem);
 211         kfree(p);
 212
 213         return ret;
 214 }
 215
 216 EXPORT_SYMBOL(unregister_blkdev);
 217
 218 static struct kobj_map *bdev_map;
 219
 220 /*
 221  * Register device numbers dev..(dev+range-1)
 222  * range must be nonzero
 223  * The hash chain is sorted on range, so that subranges can override.
 224  */
 225 void blk_register_region(dev_t dev, unsigned long range, struct module *module,
 226                          struct kobject *(*probe)(dev_t, int *, void *),
 227                          int (*lock)(dev_t, void *), void *data)
 228 {
 229         kobj_map(bdev_map, dev, range, module, probe, lock, data);
 230 }
 231
 232 EXPORT_SYMBOL(blk_register_region);
 233
 234 void blk_unregister_region(dev_t dev, unsigned long range)
 235 {
 236         kobj_unmap(bdev_map, dev, range);
 237 }
 238
 239 EXPORT_SYMBOL(blk_unregister_region);
 240
 241 static struct kobject *exact_match(dev_t dev, int *part, void *data)
 242 {
 243         struct gendisk *p = data;
 244         return &p->kobj;
 245 }
 246
 247 static int exact_lock(dev_t dev, void *data)
 248 {
 249         struct gendisk *p = data;
 250
 251         if (!get_disk(p))
 252                 return -1;
 253         return 0;
 254 }
 255
 256 /**
 257  * add_disk - add partitioning information to kernel list
 258  * @disk: per-device partitioning information
 259  *
 260  * This function registers the partitioning information in @disk
 261  * with the kernel.
 262  */
 263 void add_disk(struct gendisk *disk)
 264 {
 265         disk->flags |= GENHD_FL_UP;
 266         blk_register_region(MKDEV(disk->major, disk->first_minor),
 267                             disk->minors, NULL, exact_match, exact_lock, disk);
 268         register_disk(disk);
 269         blk_register_queue(disk);
 270 }
 271
 272 EXPORT_SYMBOL(add_disk);
 273 EXPORT_SYMBOL(del_gendisk);     /* in partitions/check.c */
 274
 275 void unlink_gendisk(struct gendisk *disk)
 276 {
 277         blk_unregister_queue(disk);
 278         blk_unregister_region(MKDEV(disk->major, disk->first_minor),
 279                               disk->minors);
 280 }
 281
 282 #define to_disk(obj) container_of(obj,struct gendisk,kobj)
 283
 284 /**
 285  * get_gendisk - get partitioning information for a given device
 286  * @dev: device to get partitioning information for
 287  *
 288  * This function gets the structure containing partitioning
 289  * information for the given device @dev.
 290  */
 291 struct gendisk *get_gendisk(dev_t dev, int *part)
 292 {
 293         struct kobject *kobj = kobj_lookup(bdev_map, dev, part);
 294         return  kobj ? to_disk(kobj) : NULL;
 295 }
 296
 297 #ifdef CONFIG_PROC_FS
 298 /* iterator */
 299 static void *part_start(struct seq_file *part, loff_t *pos)
 300 {
 301         struct list_head *p;
 302         loff_t l = *pos;
 303
 304         down(&block_subsys_sem);
 305         list_for_each(p, &block_subsys.kset.list)
 306                 if (!l--)
 307                         return list_entry(p, struct gendisk, kobj.entry);
 308         return NULL;
 309 }
 310
 311 static void *part_next(struct seq_file *part, void *v, loff_t *pos)
 312 {
 313         struct list_head *p = ((struct gendisk *)v)->kobj.entry.next;
 314         ++*pos;
 315         return p==&block_subsys.kset.list ? NULL :
 316                 list_entry(p, struct gendisk, kobj.entry);
 317 }
 318
 319 static void part_stop(struct seq_file *part, void *v)
 320 {
 321         up(&block_subsys_sem);
 322 }
 323
 324 static int show_partition(struct seq_file *part, void *v)
 325 {
 326         struct gendisk *sgp = v;
 327         int n;
 328         char buf[BDEVNAME_SIZE];
 329
 330         if (&sgp->kobj.entry == block_subsys.kset.list.next)
 331                 seq_puts(part, "major minor  #blocks  name\n\n");
 332
 333         /* Don't show non-partitionable removeable devices or empty devices */
 334         if (!get_capacity(sgp) ||
 335                         (sgp->minors == 1 && (sgp->flags & GENHD_FL_REMOVABLE)))
 336                 return 0;
 337         if (sgp->flags & GENHD_FL_SUPPRESS_PARTITION_INFO)
 338                 return 0;
 339
 340         /* show the full disk and all non-0 size partitions of it */
 341         seq_printf(part, "%4d  %4d %10llu %s\n",
 342                 sgp->major, sgp->first_minor,
 343                 (unsigned long long)get_capacity(sgp) >> 1,
 344                 disk_name(sgp, 0, buf));
 345         for (n = 0; n < sgp->minors - 1; n++) {
 346                 if (!sgp->part[n])
 347                         continue;
 348                 if (sgp->part[n]->nr_sects == 0)
 349                         continue;
 350                 seq_printf(part, "%4d  %4d %10llu %s\n",
 351                         sgp->major, n + 1 + sgp->first_minor,
 352                         (unsigned long long)sgp->part[n]->nr_sects >> 1 ,
 353                         disk_name(sgp, n + 1, buf));
 354         }
 355
 356         return 0;
 357 }
 358
 359 struct seq_operations partitions_op = {
 360         .start =part_start,
 361         .next = part_next,
 362         .stop = part_stop,
 363         .show = show_partition
 364 };
 365 #endif
 366
 367
 368 extern int blk_dev_init(void);
 369
 370 static struct kobject *base_probe(dev_t dev, int *part, void *data)
 371 {
 372         if (request_module("block-major-%d-%d", MAJOR(dev), MINOR(dev)) > 0)
 373                 /* Make old-style 2.4 aliases work */
 374                 request_module("block-major-%d", MAJOR(dev));
 375         return NULL;
 376 }
 377
 378 static int __init genhd_device_init(void)
 379 {
 380         bdev_map = kobj_map_init(base_probe, &block_subsys_sem);
 381         blk_dev_init();
 382         subsystem_register(&block_subsys);
 383         return 0;
 384 }
 385
 386 subsys_initcall(genhd_device_init);
 387
 388
 389
 390 /*
 391  * kobject & sysfs bindings for block devices
 392  */
 393 static ssize_t disk_attr_show(struct kobject *kobj, struct attribute *attr,
 394                               char *page)
 395 {
 396         struct gendisk *disk = to_disk(kobj);
 397         struct disk_attribute *disk_attr =
 398                 container_of(attr,struct disk_attribute,attr);
 399         ssize_t ret = -EIO;
 400
 401         if (disk_attr->show)
 402                 ret = disk_attr->show(disk,page);
 403         return ret;
 404 }
 405
 406 static ssize_t disk_attr_store(struct kobject * kobj, struct attribute * attr,
 407                                const char *page, size_t count)
 408 {
 409         struct gendisk *disk = to_disk(kobj);
 410         struct disk_attribute *disk_attr =
 411                 container_of(attr,struct disk_attribute,attr);
 412         ssize_t ret = 0;
 413
 414         if (disk_attr->store)
 415                 ret = disk_attr->store(disk, page, count);
 416         return ret;
 417 }
 418
 419 static struct sysfs_ops disk_sysfs_ops = {
 420         .show   = &disk_attr_show,
 421         .store  = &disk_attr_store,
 422 };
 423
 424 static ssize_t disk_uevent_store(struct gendisk * disk,
 425                                  const char *buf, size_t count)
 426 {
 427         kobject_uevent(&disk->kobj, KOBJ_ADD);
 428         return count;
 429 }
 430 static ssize_t disk_dev_read(struct gendisk * disk, char *page)
 431 {
 432         dev_t base = MKDEV(disk->major, disk->first_minor);
 433         return print_dev_t(page, base);
 434 }
 435 static ssize_t disk_range_read(struct gendisk * disk, char *page)
 436 {
 437         return sprintf(page, "%d\n", disk->minors);
 438 }
 439 static ssize_t disk_removable_read(struct gendisk * disk, char *page)
 440 {
 441         return sprintf(page, "%d\n",
 442                        (disk->flags & GENHD_FL_REMOVABLE ? 1 : 0));
 443
 444 }
 445 static ssize_t disk_size_read(struct gendisk * disk, char *page)
 446 {
 447         return sprintf(page, "%llu\n", (unsigned long long)get_capacity(disk));
 448 }
 449
 450 static ssize_t disk_stats_read(struct gendisk * disk, char *page)
 451 {
 452         preempt_disable();
 453         disk_round_stats(disk);
 454         preempt_enable();
 455         return sprintf(page,
 456                 "%8u %8u %8llu %8u "
 457                 "%8u %8u %8llu %8u "
 458                 "%8u %8u %8u"
 459                 "\n",
 460                 disk_stat_read(disk, ios[READ]),
 461                 disk_stat_read(disk, merges[READ]),
 462                 (unsigned long long)disk_stat_read(disk, sectors[READ]),
 463                 jiffies_to_msecs(disk_stat_read(disk, ticks[READ])),
 464                 disk_stat_read(disk, ios[WRITE]),
 465                 disk_stat_read(disk, merges[WRITE]),
 466                 (unsigned long long)disk_stat_read(disk, sectors[WRITE]),
 467                 jiffies_to_msecs(disk_stat_read(disk, ticks[WRITE])),
 468                 disk->in_flight,
 469                 jiffies_to_msecs(disk_stat_read(disk, io_ticks)),
 470                 jiffies_to_msecs(disk_stat_read(disk, time_in_queue)));
 471 }
 472 static struct disk_attribute disk_attr_uevent = {
 473         .attr = {.name = "uevent", .mode = S_IWUSR },
 474         .store  = disk_uevent_store
 475 };
 476 static struct disk_attribute disk_attr_dev = {
 477         .attr = {.name = "dev", .mode = S_IRUGO },
 478         .show   = disk_dev_read
 479 };
 480 static struct disk_attribute disk_attr_range = {
 481         .attr = {.name = "range", .mode = S_IRUGO },
 482         .show   = disk_range_read
 483 };
 484 static struct disk_attribute disk_attr_removable = {
 485         .attr = {.name = "removable", .mode = S_IRUGO },
 486         .show   = disk_removable_read
 487 };
 488 static struct disk_attribute disk_attr_size = {
 489         .attr = {.name = "size", .mode = S_IRUGO },
 490         .show   = disk_size_read
 491 };
 492 static struct disk_attribute disk_attr_stat = {
 493         .attr = {.name = "stat", .mode = S_IRUGO },
 494         .show   = disk_stats_read
 495 };
 496
 497 static struct attribute * default_attrs[] = {
 498         &disk_attr_uevent.attr,
 499         &disk_attr_dev.attr,
 500         &disk_attr_range.attr,
 501         &disk_attr_removable.attr,
 502         &disk_attr_size.attr,
 503         &disk_attr_stat.attr,
 504         NULL,
 505 };
 506
 507 static void disk_release(struct kobject * kobj)
 508 {
 509         struct gendisk *disk = to_disk(kobj);
 510         kfree(disk->random);
 511         kfree(disk->part);
 512         free_disk_stats(disk);
 513         kfree(disk);
 514 }
 515
 516 static struct kobj_type ktype_block = {
 517         .release        = disk_release,
 518         .sysfs_ops      = &disk_sysfs_ops,
 519         .default_attrs  = default_attrs,
 520 };
 521
 522 extern struct kobj_type ktype_part;
 523
 524 static int block_uevent_filter(struct kset *kset, struct kobject *kobj)
 525 {
 526         struct kobj_type *ktype = get_ktype(kobj);
 527
 528         return ((ktype == &ktype_block) || (ktype == &ktype_part));
 529 }
 530
 531 static int block_uevent(struct kset *kset, struct kobject *kobj, char **envp,
 532                          int num_envp, char *buffer, int buffer_size)
 533 {
 534         struct kobj_type *ktype = get_ktype(kobj);
 535         struct device *physdev;
 536         struct gendisk *disk;
 537         struct hd_struct *part;
 538         int length = 0;
 539         int i = 0;
 540
 541         if (ktype == &ktype_block) {
 542                 disk = container_of(kobj, struct gendisk, kobj);
 543                 add_uevent_var(envp, num_envp, &i, buffer, buffer_size,
 544                                &length, "MINOR=%u", disk->first_minor);
 545         } else if (ktype == &ktype_part) {
 546                 disk = container_of(kobj->parent, struct gendisk, kobj);
 547                 part = container_of(kobj, struct hd_struct, kobj);
 548                 add_uevent_var(envp, num_envp, &i, buffer, buffer_size,
 549                                &length, "MINOR=%u",
 550                                disk->first_minor + part->partno);
 551         } else
 552                 return 0;
 553
 554         add_uevent_var(envp, num_envp, &i, buffer, buffer_size, &length,
 555                        "MAJOR=%u", disk->major);
 556
 557         /* add physical device, backing this device  */
 558         physdev = disk->driverfs_dev;
 559         if (physdev) {
 560                 char *path = kobject_get_path(&physdev->kobj, GFP_KERNEL);
 561
 562                 add_uevent_var(envp, num_envp, &i, buffer, buffer_size,
 563                                &length, "PHYSDEVPATH=%s", path);
 564                 kfree(path);
 565
 566                 if (physdev->bus)
 567                         add_uevent_var(envp, num_envp, &i,
 568                                        buffer, buffer_size, &length,
 569                                        "PHYSDEVBUS=%s",
 570                                        physdev->bus->name);
 571
 572                 if (physdev->driver)
 573                         add_uevent_var(envp, num_envp, &i,
 574                                        buffer, buffer_size, &length,
 575                                        "PHYSDEVDRIVER=%s",
 576                                        physdev->driver->name);
 577         }
 578
 579         /* terminate, set to next free slot, shrink available space */
 580         envp[i] = NULL;
 581         envp = &envp[i];
 582         num_envp -= i;
 583         buffer = &buffer[length];
 584         buffer_size -= length;
 585
 586         return 0;
 587 }
 588
 589 static struct kset_uevent_ops block_uevent_ops = {
 590         .filter         = block_uevent_filter,
 591         .uevent         = block_uevent,
 592 };
 593
 594 /* declare block_subsys. */
 595 static decl_subsys(block, &ktype_block, &block_uevent_ops);
 596
 597
 598 /*
 599  * aggregate disk stat collector.  Uses the same stats that the sysfs
 600  * entries do, above, but makes them available through one seq_file.
 601  * Watching a few disks may be efficient through sysfs, but watching
 602  * all of them will be more efficient through this interface.
 603  *
 604  * The output looks suspiciously like /proc/partitions with a bunch of
 605  * extra fields.
 606  */
 607
 608 /* iterator */
 609 static void *diskstats_start(struct seq_file *part, loff_t *pos)
 610 {
 611         loff_t k = *pos;
 612         struct list_head *p;
 613
 614         down(&block_subsys_sem);
 615         list_for_each(p, &block_subsys.kset.list)
 616                 if (!k--)
 617                         return list_entry(p, struct gendisk, kobj.entry);
 618         return NULL;
 619 }
 620
 621 static void *diskstats_next(struct seq_file *part, void *v, loff_t *pos)
 622 {
 623         struct list_head *p = ((struct gendisk *)v)->kobj.entry.next;
 624         ++*pos;
 625         return p==&block_subsys.kset.list ? NULL :
 626                 list_entry(p, struct gendisk, kobj.entry);
 627 }
 628
 629 static void diskstats_stop(struct seq_file *part, void *v)
 630 {
 631         up(&block_subsys_sem);
 632 }
 633
 634 static int diskstats_show(struct seq_file *s, void *v)
 635 {
 636         struct gendisk *gp = v;
 637         char buf[BDEVNAME_SIZE];
 638         int n = 0;
 639
 640         /*
 641         if (&sgp->kobj.entry == block_subsys.kset.list.next)
 642                 seq_puts(s,     "major minor name"
 643                                 "     rio rmerge rsect ruse wio wmerge "
 644                                 "wsect wuse running use aveq"
 645                                 "\n\n");
 646         */
 647
 648         preempt_disable();
 649         disk_round_stats(gp);
 650         preempt_enable();
 651         seq_printf(s, "%4d %4d %s %u %u %llu %u %u %u %llu %u %u %u %u\n",
 652                 gp->major, n + gp->first_minor, disk_name(gp, n, buf),
 653                 disk_stat_read(gp, ios[0]), disk_stat_read(gp, merges[0]),
 654                 (unsigned long long)disk_stat_read(gp, sectors[0]),
 655                 jiffies_to_msecs(disk_stat_read(gp, ticks[0])),
 656                 disk_stat_read(gp, ios[1]), disk_stat_read(gp, merges[1]),
 657                 (unsigned long long)disk_stat_read(gp, sectors[1]),
 658                 jiffies_to_msecs(disk_stat_read(gp, ticks[1])),
 659                 gp->in_flight,
 660                 jiffies_to_msecs(disk_stat_read(gp, io_ticks)),
 661                 jiffies_to_msecs(disk_stat_read(gp, time_in_queue)));
 662
 663         /* now show all non-0 size partitions of it */
 664         for (n = 0; n < gp->minors - 1; n++) {
 665                 struct hd_struct *hd = gp->part[n];
 666
 667                 if (hd && hd->nr_sects)
 668                         seq_printf(s, "%4d %4d %s %u %u %u %u\n",
 669                                 gp->major, n + gp->first_minor + 1,
 670                                 disk_name(gp, n + 1, buf),
 671                                 hd->ios[0], hd->sectors[0],
 672                                 hd->ios[1], hd->sectors[1]);
 673         }
 674
 675         return 0;
 676 }
 677
 678 struct seq_operations diskstats_op = {
 679         .start  = diskstats_start,
 680         .next   = diskstats_next,
 681         .stop   = diskstats_stop,
 682         .show   = diskstats_show
 683 };
 684
 685 struct gendisk *alloc_disk(int minors)
 686 {
 687         return alloc_disk_node(minors, -1);
 688 }
 689
 690 struct gendisk *alloc_disk_node(int minors, int node_id)
 691 {
 692         struct gendisk *disk;
 693
 694         disk = kmalloc_node(sizeof(struct gendisk), GFP_KERNEL, node_id);
 695         if (disk) {
 696                 memset(disk, 0, sizeof(struct gendisk));
 697                 if (!init_disk_stats(disk)) {
 698                         kfree(disk);
 699                         return NULL;
 700                 }
 701                 if (minors > 1) {
 702                         int size = (minors - 1) * sizeof(struct hd_struct *);
 703                         disk->part = kmalloc_node(size, GFP_KERNEL, node_id);
 704                         if (!disk->part) {
 705                                 kfree(disk);
 706                                 return NULL;
 707                         }
 708                         memset(disk->part, 0, size);
 709                 }
 710                 disk->minors = minors;
 711                 kobj_set_kset_s(disk,block_subsys);
 712                 kobject_init(&disk->kobj);
 713                 rand_initialize_disk(disk);
 714         }
 715         return disk;
 716 }
 717
 718 EXPORT_SYMBOL(alloc_disk);
 719 EXPORT_SYMBOL(alloc_disk_node);
 720
 721 struct kobject *get_disk(struct gendisk *disk)
 722 {
 723         struct module *owner;
 724         struct kobject *kobj;
 725
 726         if (!disk->fops)
 727                 return NULL;
 728         owner = disk->fops->owner;
 729         if (owner && !try_module_get(owner))
 730                 return NULL;
 731         kobj = kobject_get(&disk->kobj);
 732         if (kobj == NULL) {
 733                 module_put(owner);
 734                 return NULL;
 735         }
 736         return kobj;
 737
 738 }
 739
 740 EXPORT_SYMBOL(get_disk);
 741
 742 void put_disk(struct gendisk *disk)
 743 {
 744         if (disk)
 745                 kobject_put(&disk->kobj);
 746 }
 747
 748 EXPORT_SYMBOL(put_disk);
 749
 750 void set_device_ro(struct block_device *bdev, int flag)
 751 {
 752         if (bdev->bd_contains != bdev)
 753                 bdev->bd_part->policy = flag;
 754         else
 755                 bdev->bd_disk->policy = flag;
 756 }
 757
 758 EXPORT_SYMBOL(set_device_ro);
 759
 760 void set_disk_ro(struct gendisk *disk, int flag)
 761 {
 762         int i;
 763         disk->policy = flag;
 764         for (i = 0; i < disk->minors - 1; i++)
 765                 if (disk->part[i]) disk->part[i]->policy = flag;
 766 }
 767
 768 EXPORT_SYMBOL(set_disk_ro);
 769
 770 int bdev_read_only(struct block_device *bdev)
 771 {
 772         if (!bdev)
 773                 return 0;
 774         else if (bdev->bd_contains != bdev)
 775                 return bdev->bd_part->policy;
 776         else
 777                 return bdev->bd_disk->policy;
 778 }
 779
 780 EXPORT_SYMBOL(bdev_read_only);
 781
 782 int invalidate_partition(struct gendisk *disk, int index)
 783 {
 784         int res = 0;
 785         struct block_device *bdev = bdget_disk(disk, index);
 786         if (bdev) {
 787                 fsync_bdev(bdev);
 788                 res = __invalidate_device(bdev);
 789                 bdput(bdev);
 790         }
 791         return res;
 792 }
 793
 794 EXPORT_SYMBOL(invalidate_partition);