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