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