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 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         bdev_map = kobj_map_init(base_probe, &block_subsys_lock);
 300         blk_dev_init();
 301         subsystem_register(&block_subsys);
 302         return 0;
 303 }
 304
 305 subsys_initcall(genhd_device_init);
 306
 307
 308
 309 /*
 310  * kobject & sysfs bindings for block devices
 311  */
 312 static ssize_t disk_attr_show(struct kobject *kobj, struct attribute *attr,
 313                               char *page)
 314 {
 315         struct gendisk *disk = to_disk(kobj);
 316         struct disk_attribute *disk_attr =
 317                 container_of(attr,struct disk_attribute,attr);
 318         ssize_t ret = -EIO;
 319
 320         if (disk_attr->show)
 321                 ret = disk_attr->show(disk,page);
 322         return ret;
 323 }
 324
 325 static ssize_t disk_attr_store(struct kobject * kobj, struct attribute * attr,
 326                                const char *page, size_t count)
 327 {
 328         struct gendisk *disk = to_disk(kobj);
 329         struct disk_attribute *disk_attr =
 330                 container_of(attr,struct disk_attribute,attr);
 331         ssize_t ret = 0;
 332
 333         if (disk_attr->store)
 334                 ret = disk_attr->store(disk, page, count);
 335         return ret;
 336 }
 337
 338 static struct sysfs_ops disk_sysfs_ops = {
 339         .show   = &disk_attr_show,
 340         .store  = &disk_attr_store,
 341 };
 342
 343 static ssize_t disk_uevent_store(struct gendisk * disk,
 344                                  const char *buf, size_t count)
 345 {
 346         kobject_uevent(&disk->kobj, KOBJ_ADD);
 347         return count;
 348 }
 349 static ssize_t disk_dev_read(struct gendisk * disk, char *page)
 350 {
 351         dev_t base = MKDEV(disk->major, disk->first_minor);
 352         return print_dev_t(page, base);
 353 }
 354 static ssize_t disk_range_read(struct gendisk * disk, char *page)
 355 {
 356         return sprintf(page, "%d\n", disk->minors);
 357 }
 358 static ssize_t disk_removable_read(struct gendisk * disk, char *page)
 359 {
 360         return sprintf(page, "%d\n",
 361                        (disk->flags & GENHD_FL_REMOVABLE ? 1 : 0));
 362
 363 }
 364 static ssize_t disk_size_read(struct gendisk * disk, char *page)
 365 {
 366         return sprintf(page, "%llu\n", (unsigned long long)get_capacity(disk));
 367 }
 368
 369 static ssize_t disk_stats_read(struct gendisk * disk, char *page)
 370 {
 371         preempt_disable();
 372         disk_round_stats(disk);
 373         preempt_enable();
 374         return sprintf(page,
 375                 "%8lu %8lu %8llu %8u "
 376                 "%8lu %8lu %8llu %8u "
 377                 "%8u %8u %8u"
 378                 "\n",
 379                 disk_stat_read(disk, ios[READ]),
 380                 disk_stat_read(disk, merges[READ]),
 381                 (unsigned long long)disk_stat_read(disk, sectors[READ]),
 382                 jiffies_to_msecs(disk_stat_read(disk, ticks[READ])),
 383                 disk_stat_read(disk, ios[WRITE]),
 384                 disk_stat_read(disk, merges[WRITE]),
 385                 (unsigned long long)disk_stat_read(disk, sectors[WRITE]),
 386                 jiffies_to_msecs(disk_stat_read(disk, ticks[WRITE])),
 387                 disk->in_flight,
 388                 jiffies_to_msecs(disk_stat_read(disk, io_ticks)),
 389                 jiffies_to_msecs(disk_stat_read(disk, time_in_queue)));
 390 }
 391 static struct disk_attribute disk_attr_uevent = {
 392         .attr = {.name = "uevent", .mode = S_IWUSR },
 393         .store  = disk_uevent_store
 394 };
 395 static struct disk_attribute disk_attr_dev = {
 396         .attr = {.name = "dev", .mode = S_IRUGO },
 397         .show   = disk_dev_read
 398 };
 399 static struct disk_attribute disk_attr_range = {
 400         .attr = {.name = "range", .mode = S_IRUGO },
 401         .show   = disk_range_read
 402 };
 403 static struct disk_attribute disk_attr_removable = {
 404         .attr = {.name = "removable", .mode = S_IRUGO },
 405         .show   = disk_removable_read
 406 };
 407 static struct disk_attribute disk_attr_size = {
 408         .attr = {.name = "size", .mode = S_IRUGO },
 409         .show   = disk_size_read
 410 };
 411 static struct disk_attribute disk_attr_stat = {
 412         .attr = {.name = "stat", .mode = S_IRUGO },
 413         .show   = disk_stats_read
 414 };
 415
 416 static struct attribute * default_attrs[] = {
 417         &disk_attr_uevent.attr,
 418         &disk_attr_dev.attr,
 419         &disk_attr_range.attr,
 420         &disk_attr_removable.attr,
 421         &disk_attr_size.attr,
 422         &disk_attr_stat.attr,
 423         NULL,
 424 };
 425
 426 static void disk_release(struct kobject * kobj)
 427 {
 428         struct gendisk *disk = to_disk(kobj);
 429         kfree(disk->random);
 430         kfree(disk->part);
 431         free_disk_stats(disk);
 432         kfree(disk);
 433 }
 434
 435 static struct kobj_type ktype_block = {
 436         .release        = disk_release,
 437         .sysfs_ops      = &disk_sysfs_ops,
 438         .default_attrs  = default_attrs,
 439 };
 440
 441 extern struct kobj_type ktype_part;
 442
 443 static int block_uevent_filter(struct kset *kset, struct kobject *kobj)
 444 {
 445         struct kobj_type *ktype = get_ktype(kobj);
 446
 447         return ((ktype == &ktype_block) || (ktype == &ktype_part));
 448 }
 449
 450 static int block_uevent(struct kset *kset, struct kobject *kobj, char **envp,
 451                          int num_envp, char *buffer, int buffer_size)
 452 {
 453         struct kobj_type *ktype = get_ktype(kobj);
 454         struct device *physdev;
 455         struct gendisk *disk;
 456         struct hd_struct *part;
 457         int length = 0;
 458         int i = 0;
 459
 460         if (ktype == &ktype_block) {
 461                 disk = container_of(kobj, struct gendisk, kobj);
 462                 add_uevent_var(envp, num_envp, &i, buffer, buffer_size,
 463                                &length, "MINOR=%u", disk->first_minor);
 464         } else if (ktype == &ktype_part) {
 465                 disk = container_of(kobj->parent, struct gendisk, kobj);
 466                 part = container_of(kobj, struct hd_struct, kobj);
 467                 add_uevent_var(envp, num_envp, &i, buffer, buffer_size,
 468                                &length, "MINOR=%u",
 469                                disk->first_minor + part->partno);
 470         } else
 471                 return 0;
 472
 473         add_uevent_var(envp, num_envp, &i, buffer, buffer_size, &length,
 474                        "MAJOR=%u", disk->major);
 475
 476         /* add physical device, backing this device  */
 477         physdev = disk->driverfs_dev;
 478         if (physdev) {
 479                 char *path = kobject_get_path(&physdev->kobj, GFP_KERNEL);
 480
 481                 add_uevent_var(envp, num_envp, &i, buffer, buffer_size,
 482                                &length, "PHYSDEVPATH=%s", path);
 483                 kfree(path);
 484
 485                 if (physdev->bus)
 486                         add_uevent_var(envp, num_envp, &i,
 487                                        buffer, buffer_size, &length,
 488                                        "PHYSDEVBUS=%s",
 489                                        physdev->bus->name);
 490
 491                 if (physdev->driver)
 492                         add_uevent_var(envp, num_envp, &i,
 493                                        buffer, buffer_size, &length,
 494                                        "PHYSDEVDRIVER=%s",
 495                                        physdev->driver->name);
 496         }
 497
 498         /* terminate, set to next free slot, shrink available space */
 499         envp[i] = NULL;
 500         envp = &envp[i];
 501         num_envp -= i;
 502         buffer = &buffer[length];
 503         buffer_size -= length;
 504
 505         return 0;
 506 }
 507
 508 static struct kset_uevent_ops block_uevent_ops = {
 509         .filter         = block_uevent_filter,
 510         .uevent         = block_uevent,
 511 };
 512
 513 decl_subsys(block, &ktype_block, &block_uevent_ops);
 514
 515 /*
 516  * aggregate disk stat collector.  Uses the same stats that the sysfs
 517  * entries do, above, but makes them available through one seq_file.
 518  * Watching a few disks may be efficient through sysfs, but watching
 519  * all of them will be more efficient through this interface.
 520  *
 521  * The output looks suspiciously like /proc/partitions with a bunch of
 522  * extra fields.
 523  */
 524
 525 /* iterator */
 526 static void *diskstats_start(struct seq_file *part, loff_t *pos)
 527 {
 528         loff_t k = *pos;
 529         struct list_head *p;
 530
 531         mutex_lock(&block_subsys_lock);
 532         list_for_each(p, &block_subsys.kset.list)
 533                 if (!k--)
 534                         return list_entry(p, struct gendisk, kobj.entry);
 535         return NULL;
 536 }
 537
 538 static void *diskstats_next(struct seq_file *part, void *v, loff_t *pos)
 539 {
 540         struct list_head *p = ((struct gendisk *)v)->kobj.entry.next;
 541         ++*pos;
 542         return p==&block_subsys.kset.list ? NULL :
 543                 list_entry(p, struct gendisk, kobj.entry);
 544 }
 545
 546 static void diskstats_stop(struct seq_file *part, void *v)
 547 {
 548         mutex_unlock(&block_subsys_lock);
 549 }
 550
 551 static int diskstats_show(struct seq_file *s, void *v)
 552 {
 553         struct gendisk *gp = v;
 554         char buf[BDEVNAME_SIZE];
 555         int n = 0;
 556
 557         /*
 558         if (&sgp->kobj.entry == block_subsys.kset.list.next)
 559                 seq_puts(s,     "major minor name"
 560                                 "     rio rmerge rsect ruse wio wmerge "
 561                                 "wsect wuse running use aveq"
 562                                 "\n\n");
 563         */
 564
 565         preempt_disable();
 566         disk_round_stats(gp);
 567         preempt_enable();
 568         seq_printf(s, "%4d %4d %s %lu %lu %llu %u %lu %lu %llu %u %u %u %u\n",
 569                 gp->major, n + gp->first_minor, disk_name(gp, n, buf),
 570                 disk_stat_read(gp, ios[0]), disk_stat_read(gp, merges[0]),
 571                 (unsigned long long)disk_stat_read(gp, sectors[0]),
 572                 jiffies_to_msecs(disk_stat_read(gp, ticks[0])),
 573                 disk_stat_read(gp, ios[1]), disk_stat_read(gp, merges[1]),
 574                 (unsigned long long)disk_stat_read(gp, sectors[1]),
 575                 jiffies_to_msecs(disk_stat_read(gp, ticks[1])),
 576                 gp->in_flight,
 577                 jiffies_to_msecs(disk_stat_read(gp, io_ticks)),
 578                 jiffies_to_msecs(disk_stat_read(gp, time_in_queue)));
 579
 580         /* now show all non-0 size partitions of it */
 581         for (n = 0; n < gp->minors - 1; n++) {
 582                 struct hd_struct *hd = gp->part[n];
 583
 584                 if (hd && hd->nr_sects)
 585                         seq_printf(s, "%4d %4d %s %u %u %u %u\n",
 586                                 gp->major, n + gp->first_minor + 1,
 587                                 disk_name(gp, n + 1, buf),
 588                                 hd->ios[0], hd->sectors[0],
 589                                 hd->ios[1], hd->sectors[1]);
 590         }
 591
 592         return 0;
 593 }
 594
 595 struct seq_operations diskstats_op = {
 596         .start  = diskstats_start,
 597         .next   = diskstats_next,
 598         .stop   = diskstats_stop,
 599         .show   = diskstats_show
 600 };
 601
 602 struct gendisk *alloc_disk(int minors)
 603 {
 604         return alloc_disk_node(minors, -1);
 605 }
 606
 607 struct gendisk *alloc_disk_node(int minors, int node_id)
 608 {
 609         struct gendisk *disk;
 610
 611         disk = kmalloc_node(sizeof(struct gendisk), GFP_KERNEL, node_id);
 612         if (disk) {
 613                 memset(disk, 0, sizeof(struct gendisk));
 614                 if (!init_disk_stats(disk)) {
 615                         kfree(disk);
 616                         return NULL;
 617                 }
 618                 if (minors > 1) {
 619                         int size = (minors - 1) * sizeof(struct hd_struct *);
 620                         disk->part = kmalloc_node(size, GFP_KERNEL, node_id);
 621                         if (!disk->part) {
 622                                 kfree(disk);
 623                                 return NULL;
 624                         }
 625                         memset(disk->part, 0, size);
 626                 }
 627                 disk->minors = minors;
 628                 kobj_set_kset_s(disk,block_subsys);
 629                 kobject_init(&disk->kobj);
 630                 rand_initialize_disk(disk);
 631         }
 632         return disk;
 633 }
 634
 635 EXPORT_SYMBOL(alloc_disk);
 636 EXPORT_SYMBOL(alloc_disk_node);
 637
 638 struct kobject *get_disk(struct gendisk *disk)
 639 {
 640         struct module *owner;
 641         struct kobject *kobj;
 642
 643         if (!disk->fops)
 644                 return NULL;
 645         owner = disk->fops->owner;
 646         if (owner && !try_module_get(owner))
 647                 return NULL;
 648         kobj = kobject_get(&disk->kobj);
 649         if (kobj == NULL) {
 650                 module_put(owner);
 651                 return NULL;
 652         }
 653         return kobj;
 654
 655 }
 656
 657 EXPORT_SYMBOL(get_disk);
 658
 659 void put_disk(struct gendisk *disk)
 660 {
 661         if (disk)
 662                 kobject_put(&disk->kobj);
 663 }
 664
 665 EXPORT_SYMBOL(put_disk);
 666
 667 void set_device_ro(struct block_device *bdev, int flag)
 668 {
 669         if (bdev->bd_contains != bdev)
 670                 bdev->bd_part->policy = flag;
 671         else
 672                 bdev->bd_disk->policy = flag;
 673 }
 674
 675 EXPORT_SYMBOL(set_device_ro);
 676
 677 void set_disk_ro(struct gendisk *disk, int flag)
 678 {
 679         int i;
 680         disk->policy = flag;
 681         for (i = 0; i < disk->minors - 1; i++)
 682                 if (disk->part[i]) disk->part[i]->policy = flag;
 683 }
 684
 685 EXPORT_SYMBOL(set_disk_ro);
 686
 687 int bdev_read_only(struct block_device *bdev)
 688 {
 689         if (!bdev)
 690                 return 0;
 691         else if (bdev->bd_contains != bdev)
 692                 return bdev->bd_part->policy;
 693         else
 694                 return bdev->bd_disk->policy;
 695 }
 696
 697 EXPORT_SYMBOL(bdev_read_only);
 698
 699 int invalidate_partition(struct gendisk *disk, int index)
 700 {
 701         int res = 0;
 702         struct block_device *bdev = bdget_disk(disk, index);
 703         if (bdev) {
 704                 fsync_bdev(bdev);
 705                 res = __invalidate_device(bdev);
 706                 bdput(bdev);
 707         }
 708         return res;
 709 }
 710
 711 EXPORT_SYMBOL(invalidate_partition);