block/genhd.c

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