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