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 #include "blk.h"
  21
  22 static DEFINE_MUTEX(block_class_lock);
  23 #ifndef CONFIG_SYSFS_DEPRECATED
  24 struct kobject *block_depr;
  25 #endif
  26
  27 static struct device_type disk_type;
  28
  29 /*
  30  * Can be deleted altogether. Later.
  31  *
  32  */
  33 static struct blk_major_name {
  34         struct blk_major_name *next;
  35         int major;
  36         char name[16];
  37 } *major_names[BLKDEV_MAJOR_HASH_SIZE];
  38
  39 /* index in the above - for now: assume no multimajor ranges */
  40 static inline int major_to_index(int major)
  41 {
  42         return major % BLKDEV_MAJOR_HASH_SIZE;
  43 }
  44
  45 #ifdef CONFIG_PROC_FS
  46 void blkdev_show(struct seq_file *f, off_t offset)
  47 {
  48         struct blk_major_name *dp;
  49
  50         if (offset < BLKDEV_MAJOR_HASH_SIZE) {
  51                 mutex_lock(&block_class_lock);
  52                 for (dp = major_names[offset]; dp; dp = dp->next)
  53                         seq_printf(f, "%3d %s\n", dp->major, dp->name);
  54                 mutex_unlock(&block_class_lock);
  55         }
  56 }
  57 #endif /* CONFIG_PROC_FS */
  58
  59 int register_blkdev(unsigned int major, const char *name)
  60 {
  61         struct blk_major_name **n, *p;
  62         int index, ret = 0;
  63
  64         mutex_lock(&block_class_lock);
  65
  66         /* temporary */
  67         if (major == 0) {
  68                 for (index = ARRAY_SIZE(major_names)-1; index > 0; index--) {
  69                         if (major_names[index] == NULL)
  70                                 break;
  71                 }
  72
  73                 if (index == 0) {
  74                         printk("register_blkdev: failed to get major for %s\n",
  75                                name);
  76                         ret = -EBUSY;
  77                         goto out;
  78                 }
  79                 major = index;
  80                 ret = major;
  81         }
  82
  83         p = kmalloc(sizeof(struct blk_major_name), GFP_KERNEL);
  84         if (p == NULL) {
  85                 ret = -ENOMEM;
  86                 goto out;
  87         }
  88
  89         p->major = major;
  90         strlcpy(p->name, name, sizeof(p->name));
  91         p->next = NULL;
  92         index = major_to_index(major);
  93
  94         for (n = &major_names[index]; *n; n = &(*n)->next) {
  95                 if ((*n)->major == major)
  96                         break;
  97         }
  98         if (!*n)
  99                 *n = p;
 100         else
 101                 ret = -EBUSY;
 102
 103         if (ret < 0) {
 104                 printk("register_blkdev: cannot get major %d for %s\n",
 105                        major, name);
 106                 kfree(p);
 107         }
 108 out:
 109         mutex_unlock(&block_class_lock);
 110         return ret;
 111 }
 112
 113 EXPORT_SYMBOL(register_blkdev);
 114
 115 void unregister_blkdev(unsigned int major, const char *name)
 116 {
 117         struct blk_major_name **n;
 118         struct blk_major_name *p = NULL;
 119         int index = major_to_index(major);
 120
 121         mutex_lock(&block_class_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                 WARN_ON(1);
 127         } else {
 128                 p = *n;
 129                 *n = p->next;
 130         }
 131         mutex_unlock(&block_class_lock);
 132         kfree(p);
 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 devt, 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, devt, range, module, probe, lock, data);
 149 }
 150
 151 EXPORT_SYMBOL(blk_register_region);
 152
 153 void blk_unregister_region(dev_t devt, unsigned long range)
 154 {
 155         kobj_unmap(bdev_map, devt, range);
 156 }
 157
 158 EXPORT_SYMBOL(blk_unregister_region);
 159
 160 static struct kobject *exact_match(dev_t devt, int *part, void *data)
 161 {
 162         struct gendisk *p = data;
 163
 164         return &p->dev.kobj;
 165 }
 166
 167 static int exact_lock(dev_t devt, 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         struct backing_dev_info *bdi;
 186
 187         disk->flags |= GENHD_FL_UP;
 188         blk_register_region(MKDEV(disk->major, disk->first_minor),
 189                             disk->minors, NULL, exact_match, exact_lock, disk);
 190         register_disk(disk);
 191         blk_register_queue(disk);
 192
 193         bdi = &disk->queue->backing_dev_info;
 194         bdi_register_dev(bdi, MKDEV(disk->major, disk->first_minor));
 195         sysfs_create_link(&disk->dev.kobj, &bdi->dev->kobj, "bdi");
 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         sysfs_remove_link(&disk->dev.kobj, "bdi");
 204         bdi_unregister(&disk->queue->backing_dev_info);
 205         blk_unregister_queue(disk);
 206         blk_unregister_region(MKDEV(disk->major, disk->first_minor),
 207                               disk->minors);
 208 }
 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 devt, int *part)
 218 {
 219         struct kobject *kobj = kobj_lookup(bdev_map, devt, part);
 220         struct device *dev = kobj_to_dev(kobj);
 221
 222         return  kobj ? dev_to_disk(dev) : NULL;
 223 }
 224
 225 /*
 226  * print a full list of all partitions - intended for places where the root
 227  * filesystem can't be mounted and thus to give the victim some idea of what
 228  * went wrong
 229  */
 230 void __init printk_all_partitions(void)
 231 {
 232         struct device *dev;
 233         struct gendisk *sgp;
 234         char buf[BDEVNAME_SIZE];
 235         int n;
 236
 237         mutex_lock(&block_class_lock);
 238         /* For each block device... */
 239         list_for_each_entry(dev, &block_class.devices, node) {
 240                 if (dev->type != &disk_type)
 241                         continue;
 242                 sgp = dev_to_disk(dev);
 243                 /*
 244                  * Don't show empty devices or things that have been surpressed
 245                  */
 246                 if (get_capacity(sgp) == 0 ||
 247                     (sgp->flags & GENHD_FL_SUPPRESS_PARTITION_INFO))
 248                         continue;
 249
 250                 /*
 251                  * Note, unlike /proc/partitions, I am showing the numbers in
 252                  * hex - the same format as the root= option takes.
 253                  */
 254                 printk("%02x%02x %10llu %s",
 255                         sgp->major, sgp->first_minor,
 256                         (unsigned long long)get_capacity(sgp) >> 1,
 257                         disk_name(sgp, 0, buf));
 258                 if (sgp->driverfs_dev != NULL &&
 259                     sgp->driverfs_dev->driver != NULL)
 260                         printk(" driver: %s\n",
 261                                 sgp->driverfs_dev->driver->name);
 262                 else
 263                         printk(" (driver?)\n");
 264
 265                 /* now show the partitions */
 266                 for (n = 0; n < sgp->minors - 1; ++n) {
 267                         if (sgp->part[n] == NULL)
 268                                 continue;
 269                         if (sgp->part[n]->nr_sects == 0)
 270                                 continue;
 271                         printk("  %02x%02x %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
 278         mutex_unlock(&block_class_lock);
 279 }
 280
 281 #ifdef CONFIG_PROC_FS
 282 /* iterator */
 283 static void *part_start(struct seq_file *part, loff_t *pos)
 284 {
 285         loff_t k = *pos;
 286         struct device *dev;
 287
 288         mutex_lock(&block_class_lock);
 289         list_for_each_entry(dev, &block_class.devices, node) {
 290                 if (dev->type != &disk_type)
 291                         continue;
 292                 if (!k--)
 293                         return dev_to_disk(dev);
 294         }
 295         return NULL;
 296 }
 297
 298 static void *part_next(struct seq_file *part, void *v, loff_t *pos)
 299 {
 300         struct gendisk *gp = v;
 301         struct device *dev;
 302         ++*pos;
 303         list_for_each_entry(dev, &gp->dev.node, node) {
 304                 if (&dev->node == &block_class.devices)
 305                         return NULL;
 306                 if (dev->type == &disk_type)
 307                         return dev_to_disk(dev);
 308         }
 309         return NULL;
 310 }
 311
 312 static void part_stop(struct seq_file *part, void *v)
 313 {
 314         mutex_unlock(&block_class_lock);
 315 }
 316
 317 static int show_partition(struct seq_file *part, void *v)
 318 {
 319         struct gendisk *sgp = v;
 320         int n;
 321         char buf[BDEVNAME_SIZE];
 322
 323         if (&sgp->dev.node == block_class.devices.next)
 324                 seq_puts(part, "major minor  #blocks  name\n\n");
 325
 326         /* Don't show non-partitionable removeable devices or empty devices */
 327         if (!get_capacity(sgp) ||
 328                         (sgp->minors == 1 && (sgp->flags & GENHD_FL_REMOVABLE)))
 329                 return 0;
 330         if (sgp->flags & GENHD_FL_SUPPRESS_PARTITION_INFO)
 331                 return 0;
 332
 333         /* show the full disk and all non-0 size partitions of it */
 334         seq_printf(part, "%4d  %4d %10llu %s\n",
 335                 sgp->major, sgp->first_minor,
 336                 (unsigned long long)get_capacity(sgp) >> 1,
 337                 disk_name(sgp, 0, buf));
 338         for (n = 0; n < sgp->minors - 1; n++) {
 339                 if (!sgp->part[n])
 340                         continue;
 341                 if (sgp->part[n]->nr_sects == 0)
 342                         continue;
 343                 seq_printf(part, "%4d  %4d %10llu %s\n",
 344                         sgp->major, n + 1 + sgp->first_minor,
 345                         (unsigned long long)sgp->part[n]->nr_sects >> 1 ,
 346                         disk_name(sgp, n + 1, buf));
 347         }
 348
 349         return 0;
 350 }
 351
 352 const struct seq_operations partitions_op = {
 353         .start  = part_start,
 354         .next   = part_next,
 355         .stop   = part_stop,
 356         .show   = show_partition
 357 };
 358 #endif
 359
 360
 361 static struct kobject *base_probe(dev_t devt, int *part, void *data)
 362 {
 363         if (request_module("block-major-%d-%d", MAJOR(devt), MINOR(devt)) > 0)
 364                 /* Make old-style 2.4 aliases work */
 365                 request_module("block-major-%d", MAJOR(devt));
 366         return NULL;
 367 }
 368
 369 static int __init genhd_device_init(void)
 370 {
 371         int error = class_register(&block_class);
 372         if (unlikely(error))
 373                 return error;
 374         bdev_map = kobj_map_init(base_probe, &block_class_lock);
 375         blk_dev_init();
 376
 377 #ifndef CONFIG_SYSFS_DEPRECATED
 378         /* create top-level block dir */
 379         block_depr = kobject_create_and_add("block", NULL);
 380 #endif
 381         return 0;
 382 }
 383
 384 subsys_initcall(genhd_device_init);
 385
 386 static ssize_t disk_range_show(struct device *dev,
 387                                struct device_attribute *attr, char *buf)
 388 {
 389         struct gendisk *disk = dev_to_disk(dev);
 390
 391         return sprintf(buf, "%d\n", disk->minors);
 392 }
 393
 394 static ssize_t disk_removable_show(struct device *dev,
 395                                    struct device_attribute *attr, char *buf)
 396 {
 397         struct gendisk *disk = dev_to_disk(dev);
 398
 399         return sprintf(buf, "%d\n",
 400                        (disk->flags & GENHD_FL_REMOVABLE ? 1 : 0));
 401 }
 402
 403 static ssize_t disk_size_show(struct device *dev,
 404                               struct device_attribute *attr, char *buf)
 405 {
 406         struct gendisk *disk = dev_to_disk(dev);
 407
 408         return sprintf(buf, "%llu\n", (unsigned long long)get_capacity(disk));
 409 }
 410
 411 static ssize_t disk_capability_show(struct device *dev,
 412                                     struct device_attribute *attr, char *buf)
 413 {
 414         struct gendisk *disk = dev_to_disk(dev);
 415
 416         return sprintf(buf, "%x\n", disk->flags);
 417 }
 418
 419 static ssize_t disk_stat_show(struct device *dev,
 420                               struct device_attribute *attr, char *buf)
 421 {
 422         struct gendisk *disk = dev_to_disk(dev);
 423
 424         preempt_disable();
 425         disk_round_stats(disk);
 426         preempt_enable();
 427         return sprintf(buf,
 428                 "%8lu %8lu %8llu %8u "
 429                 "%8lu %8lu %8llu %8u "
 430                 "%8u %8u %8u"
 431                 "\n",
 432                 disk_stat_read(disk, ios[READ]),
 433                 disk_stat_read(disk, merges[READ]),
 434                 (unsigned long long)disk_stat_read(disk, sectors[READ]),
 435                 jiffies_to_msecs(disk_stat_read(disk, ticks[READ])),
 436                 disk_stat_read(disk, ios[WRITE]),
 437                 disk_stat_read(disk, merges[WRITE]),
 438                 (unsigned long long)disk_stat_read(disk, sectors[WRITE]),
 439                 jiffies_to_msecs(disk_stat_read(disk, ticks[WRITE])),
 440                 disk->in_flight,
 441                 jiffies_to_msecs(disk_stat_read(disk, io_ticks)),
 442                 jiffies_to_msecs(disk_stat_read(disk, time_in_queue)));
 443 }
 444
 445 #ifdef CONFIG_FAIL_MAKE_REQUEST
 446 static ssize_t disk_fail_show(struct device *dev,
 447                               struct device_attribute *attr, char *buf)
 448 {
 449         struct gendisk *disk = dev_to_disk(dev);
 450
 451         return sprintf(buf, "%d\n", disk->flags & GENHD_FL_FAIL ? 1 : 0);
 452 }
 453
 454 static ssize_t disk_fail_store(struct device *dev,
 455                                struct device_attribute *attr,
 456                                const char *buf, size_t count)
 457 {
 458         struct gendisk *disk = dev_to_disk(dev);
 459         int i;
 460
 461         if (count > 0 && sscanf(buf, "%d", &i) > 0) {
 462                 if (i == 0)
 463                         disk->flags &= ~GENHD_FL_FAIL;
 464                 else
 465                         disk->flags |= GENHD_FL_FAIL;
 466         }
 467
 468         return count;
 469 }
 470
 471 #endif
 472
 473 static DEVICE_ATTR(range, S_IRUGO, disk_range_show, NULL);
 474 static DEVICE_ATTR(removable, S_IRUGO, disk_removable_show, NULL);
 475 static DEVICE_ATTR(size, S_IRUGO, disk_size_show, NULL);
 476 static DEVICE_ATTR(capability, S_IRUGO, disk_capability_show, NULL);
 477 static DEVICE_ATTR(stat, S_IRUGO, disk_stat_show, NULL);
 478 #ifdef CONFIG_FAIL_MAKE_REQUEST
 479 static struct device_attribute dev_attr_fail =
 480         __ATTR(make-it-fail, S_IRUGO|S_IWUSR, disk_fail_show, disk_fail_store);
 481 #endif
 482
 483 static struct attribute *disk_attrs[] = {
 484         &dev_attr_range.attr,
 485         &dev_attr_removable.attr,
 486         &dev_attr_size.attr,
 487         &dev_attr_capability.attr,
 488         &dev_attr_stat.attr,
 489 #ifdef CONFIG_FAIL_MAKE_REQUEST
 490         &dev_attr_fail.attr,
 491 #endif
 492         NULL
 493 };
 494
 495 static struct attribute_group disk_attr_group = {
 496         .attrs = disk_attrs,
 497 };
 498
 499 static struct attribute_group *disk_attr_groups[] = {
 500         &disk_attr_group,
 501         NULL
 502 };
 503
 504 static void disk_release(struct device *dev)
 505 {
 506         struct gendisk *disk = dev_to_disk(dev);
 507
 508         kfree(disk->random);
 509         kfree(disk->part);
 510         free_disk_stats(disk);
 511         kfree(disk);
 512 }
 513 struct class block_class = {
 514         .name           = "block",
 515 };
 516
 517 static struct device_type disk_type = {
 518         .name           = "disk",
 519         .groups         = disk_attr_groups,
 520         .release        = disk_release,
 521 };
 522
 523 /*
 524  * aggregate disk stat collector.  Uses the same stats that the sysfs
 525  * entries do, above, but makes them available through one seq_file.
 526  *
 527  * The output looks suspiciously like /proc/partitions with a bunch of
 528  * extra fields.
 529  */
 530
 531 static void *diskstats_start(struct seq_file *part, loff_t *pos)
 532 {
 533         loff_t k = *pos;
 534         struct device *dev;
 535
 536         mutex_lock(&block_class_lock);
 537         list_for_each_entry(dev, &block_class.devices, node) {
 538                 if (dev->type != &disk_type)
 539                         continue;
 540                 if (!k--)
 541                         return dev_to_disk(dev);
 542         }
 543         return NULL;
 544 }
 545
 546 static void *diskstats_next(struct seq_file *part, void *v, loff_t *pos)
 547 {
 548         struct gendisk *gp = v;
 549         struct device *dev;
 550
 551         ++*pos;
 552         list_for_each_entry(dev, &gp->dev.node, node) {
 553                 if (&dev->node == &block_class.devices)
 554                         return NULL;
 555                 if (dev->type == &disk_type)
 556                         return dev_to_disk(dev);
 557         }
 558         return NULL;
 559 }
 560
 561 static void diskstats_stop(struct seq_file *part, void *v)
 562 {
 563         mutex_unlock(&block_class_lock);
 564 }
 565
 566 static int diskstats_show(struct seq_file *s, void *v)
 567 {
 568         struct gendisk *gp = v;
 569         char buf[BDEVNAME_SIZE];
 570         int n = 0;
 571
 572         /*
 573         if (&gp->dev.kobj.entry == block_class.devices.next)
 574                 seq_puts(s,     "major minor name"
 575                                 "     rio rmerge rsect ruse wio wmerge "
 576                                 "wsect wuse running use aveq"
 577                                 "\n\n");
 578         */
 579
 580         preempt_disable();
 581         disk_round_stats(gp);
 582         preempt_enable();
 583         seq_printf(s, "%4d %4d %s %lu %lu %llu %u %lu %lu %llu %u %u %u %u\n",
 584                 gp->major, n + gp->first_minor, disk_name(gp, n, buf),
 585                 disk_stat_read(gp, ios[0]), disk_stat_read(gp, merges[0]),
 586                 (unsigned long long)disk_stat_read(gp, sectors[0]),
 587                 jiffies_to_msecs(disk_stat_read(gp, ticks[0])),
 588                 disk_stat_read(gp, ios[1]), disk_stat_read(gp, merges[1]),
 589                 (unsigned long long)disk_stat_read(gp, sectors[1]),
 590                 jiffies_to_msecs(disk_stat_read(gp, ticks[1])),
 591                 gp->in_flight,
 592                 jiffies_to_msecs(disk_stat_read(gp, io_ticks)),
 593                 jiffies_to_msecs(disk_stat_read(gp, time_in_queue)));
 594
 595         /* now show all non-0 size partitions of it */
 596         for (n = 0; n < gp->minors - 1; n++) {
 597                 struct hd_struct *hd = gp->part[n];
 598
 599                 if (!hd || !hd->nr_sects)
 600                         continue;
 601
 602                 preempt_disable();
 603                 part_round_stats(hd);
 604                 preempt_enable();
 605                 seq_printf(s, "%4d %4d %s %lu %lu %llu "
 606                            "%u %lu %lu %llu %u %u %u %u\n",
 607                            gp->major, n + gp->first_minor + 1,
 608                            disk_name(gp, n + 1, buf),
 609                            part_stat_read(hd, ios[0]),
 610                            part_stat_read(hd, merges[0]),
 611                            (unsigned long long)part_stat_read(hd, sectors[0]),
 612                            jiffies_to_msecs(part_stat_read(hd, ticks[0])),
 613                            part_stat_read(hd, ios[1]),
 614                            part_stat_read(hd, merges[1]),
 615                            (unsigned long long)part_stat_read(hd, sectors[1]),
 616                            jiffies_to_msecs(part_stat_read(hd, ticks[1])),
 617                            hd->in_flight,
 618                            jiffies_to_msecs(part_stat_read(hd, io_ticks)),
 619                            jiffies_to_msecs(part_stat_read(hd, time_in_queue))
 620                         );
 621         }
 622
 623         return 0;
 624 }
 625
 626 const struct seq_operations diskstats_op = {
 627         .start  = diskstats_start,
 628         .next   = diskstats_next,
 629         .stop   = diskstats_stop,
 630         .show   = diskstats_show
 631 };
 632
 633 static void media_change_notify_thread(struct work_struct *work)
 634 {
 635         struct gendisk *gd = container_of(work, struct gendisk, async_notify);
 636         char event[] = "MEDIA_CHANGE=1";
 637         char *envp[] = { event, NULL };
 638
 639         /*
 640          * set enviroment vars to indicate which event this is for
 641          * so that user space will know to go check the media status.
 642          */
 643         kobject_uevent_env(&gd->dev.kobj, KOBJ_CHANGE, envp);
 644         put_device(gd->driverfs_dev);
 645 }
 646
 647 #if 0
 648 void genhd_media_change_notify(struct gendisk *disk)
 649 {
 650         get_device(disk->driverfs_dev);
 651         schedule_work(&disk->async_notify);
 652 }
 653 EXPORT_SYMBOL_GPL(genhd_media_change_notify);
 654 #endif  /*  0  */
 655
 656 dev_t blk_lookup_devt(const char *name, int part)
 657 {
 658         struct device *dev;
 659         dev_t devt = MKDEV(0, 0);
 660
 661         mutex_lock(&block_class_lock);
 662         list_for_each_entry(dev, &block_class.devices, node) {
 663                 if (strcmp(dev->bus_id, name) == 0) {
 664                         struct gendisk *disk = dev_to_disk(dev);
 665
 666                         if (part < disk->minors)
 667                                 devt = MKDEV(MAJOR(dev->devt),
 668                                              MINOR(dev->devt) + part);
 669                         break;
 670                 }
 671         }
 672         mutex_unlock(&block_class_lock);
 673
 674         return devt;
 675 }
 676 EXPORT_SYMBOL(blk_lookup_devt);
 677
 678 struct gendisk *alloc_disk(int minors)
 679 {
 680         return alloc_disk_node(minors, -1);
 681 }
 682
 683 struct gendisk *alloc_disk_node(int minors, int node_id)
 684 {
 685         struct gendisk *disk;
 686
 687         disk = kmalloc_node(sizeof(struct gendisk),
 688                                 GFP_KERNEL | __GFP_ZERO, node_id);
 689         if (disk) {
 690                 if (!init_disk_stats(disk)) {
 691                         kfree(disk);
 692                         return NULL;
 693                 }
 694                 if (minors > 1) {
 695                         int size = (minors - 1) * sizeof(struct hd_struct *);
 696                         disk->part = kmalloc_node(size,
 697                                 GFP_KERNEL | __GFP_ZERO, node_id);
 698                         if (!disk->part) {
 699                                 free_disk_stats(disk);
 700                                 kfree(disk);
 701                                 return NULL;
 702                         }
 703                 }
 704                 disk->minors = minors;
 705                 rand_initialize_disk(disk);
 706                 disk->dev.class = &block_class;
 707                 disk->dev.type = &disk_type;
 708                 device_initialize(&disk->dev);
 709                 INIT_WORK(&disk->async_notify,
 710                         media_change_notify_thread);
 711         }
 712         return disk;
 713 }
 714
 715 EXPORT_SYMBOL(alloc_disk);
 716 EXPORT_SYMBOL(alloc_disk_node);
 717
 718 struct kobject *get_disk(struct gendisk *disk)
 719 {
 720         struct module *owner;
 721         struct kobject *kobj;
 722
 723         if (!disk->fops)
 724                 return NULL;
 725         owner = disk->fops->owner;
 726         if (owner && !try_module_get(owner))
 727                 return NULL;
 728         kobj = kobject_get(&disk->dev.kobj);
 729         if (kobj == NULL) {
 730                 module_put(owner);
 731                 return NULL;
 732         }
 733         return kobj;
 734
 735 }
 736
 737 EXPORT_SYMBOL(get_disk);
 738
 739 void put_disk(struct gendisk *disk)
 740 {
 741         if (disk)
 742                 kobject_put(&disk->dev.kobj);
 743 }
 744
 745 EXPORT_SYMBOL(put_disk);
 746
 747 void set_device_ro(struct block_device *bdev, int flag)
 748 {
 749         if (bdev->bd_contains != bdev)
 750                 bdev->bd_part->policy = flag;
 751         else
 752                 bdev->bd_disk->policy = flag;
 753 }
 754
 755 EXPORT_SYMBOL(set_device_ro);
 756
 757 void set_disk_ro(struct gendisk *disk, int flag)
 758 {
 759         int i;
 760         disk->policy = flag;
 761         for (i = 0; i < disk->minors - 1; i++)
 762                 if (disk->part[i]) disk->part[i]->policy = flag;
 763 }
 764
 765 EXPORT_SYMBOL(set_disk_ro);
 766
 767 int bdev_read_only(struct block_device *bdev)
 768 {
 769         if (!bdev)
 770                 return 0;
 771         else if (bdev->bd_contains != bdev)
 772                 return bdev->bd_part->policy;
 773         else
 774                 return bdev->bd_disk->policy;
 775 }
 776
 777 EXPORT_SYMBOL(bdev_read_only);
 778
 779 int invalidate_partition(struct gendisk *disk, int index)
 780 {
 781         int res = 0;
 782         struct block_device *bdev = bdget_disk(disk, index);
 783         if (bdev) {
 784                 fsync_bdev(bdev);
 785                 res = __invalidate_device(bdev);
 786                 bdput(bdev);
 787         }
 788         return res;
 789 }
 790
 791 EXPORT_SYMBOL(invalidate_partition);