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         int retval;
 187
 188         disk->flags |= GENHD_FL_UP;
 189         blk_register_region(MKDEV(disk->major, disk->first_minor),
 190                             disk->minors, NULL, exact_match, exact_lock, disk);
 191         register_disk(disk);
 192         blk_register_queue(disk);
 193         blk_register_filter(disk);
 194
 195         bdi = &disk->queue->backing_dev_info;
 196         bdi_register_dev(bdi, MKDEV(disk->major, disk->first_minor));
 197         retval = sysfs_create_link(&disk->dev.kobj, &bdi->dev->kobj, "bdi");
 198         WARN_ON(retval);
 199 }
 200
 201 EXPORT_SYMBOL(add_disk);
 202 EXPORT_SYMBOL(del_gendisk);     /* in partitions/check.c */
 203
 204 void unlink_gendisk(struct gendisk *disk)
 205 {
 206         blk_unregister_filter(disk);
 207         sysfs_remove_link(&disk->dev.kobj, "bdi");
 208         bdi_unregister(&disk->queue->backing_dev_info);
 209         blk_unregister_queue(disk);
 210         blk_unregister_region(MKDEV(disk->major, disk->first_minor),
 211                               disk->minors);
 212 }
 213
 214 /**
 215  * get_gendisk - get partitioning information for a given device
 216  * @dev: device to get partitioning information for
 217  *
 218  * This function gets the structure containing partitioning
 219  * information for the given device @dev.
 220  */
 221 struct gendisk *get_gendisk(dev_t devt, int *part)
 222 {
 223         struct kobject *kobj = kobj_lookup(bdev_map, devt, part);
 224         struct device *dev = kobj_to_dev(kobj);
 225
 226         return  kobj ? dev_to_disk(dev) : NULL;
 227 }
 228
 229 /*
 230  * print a partitions - intended for places where the root filesystem can't be
 231  * mounted and thus to give the victim some idea of what went wrong
 232  */
 233 static int printk_partition(struct device *dev, void *data)
 234 {
 235         struct gendisk *sgp;
 236         char buf[BDEVNAME_SIZE];
 237         int n;
 238
 239         if (dev->type != &disk_type)
 240                 goto exit;
 241
 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                 goto exit;
 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                         goto exit;
 269                 if (sgp->part[n]->nr_sects == 0)
 270                         goto exit;
 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 exit:
 277         return 0;
 278 }
 279
 280 /*
 281  * print a full list of all partitions - intended for places where the root
 282  * filesystem can't be mounted and thus to give the victim some idea of what
 283  * went wrong
 284  */
 285 void __init printk_all_partitions(void)
 286 {
 287         mutex_lock(&block_class_lock);
 288         class_for_each_device(&block_class, NULL, NULL, printk_partition);
 289         mutex_unlock(&block_class_lock);
 290 }
 291
 292 #ifdef CONFIG_PROC_FS
 293 /* iterator */
 294 static int find_start(struct device *dev, void *data)
 295 {
 296         loff_t k = *(loff_t *)data;
 297
 298         if (dev->type != &disk_type)
 299                 return 0;
 300         if (!k--)
 301                 return 1;
 302         return 0;
 303 }
 304
 305 static void *part_start(struct seq_file *part, loff_t *pos)
 306 {
 307         struct device *dev;
 308         loff_t n = *pos;
 309
 310         if (!n)
 311                 seq_puts(part, "major minor  #blocks  name\n\n");
 312
 313         mutex_lock(&block_class_lock);
 314         dev = class_find_device(&block_class, NULL, (void *)pos, find_start);
 315         if (dev)
 316                 return dev_to_disk(dev);
 317         return NULL;
 318 }
 319
 320 static int find_next(struct device *dev, void *data)
 321 {
 322         if (dev->type == &disk_type)
 323                 return 1;
 324         return 0;
 325 }
 326
 327 static void *part_next(struct seq_file *part, void *v, loff_t *pos)
 328 {
 329         struct gendisk *gp = v;
 330         struct device *dev;
 331         ++*pos;
 332         dev = class_find_device(&block_class, &gp->dev, NULL, find_next);
 333         if (dev)
 334                 return dev_to_disk(dev);
 335         return NULL;
 336 }
 337
 338 static void part_stop(struct seq_file *part, void *v)
 339 {
 340         mutex_unlock(&block_class_lock);
 341 }
 342
 343 static int show_partition(struct seq_file *part, void *v)
 344 {
 345         struct gendisk *sgp = v;
 346         int n;
 347         char buf[BDEVNAME_SIZE];
 348
 349         /* Don't show non-partitionable removeable devices or empty devices */
 350         if (!get_capacity(sgp) ||
 351                         (sgp->minors == 1 && (sgp->flags & GENHD_FL_REMOVABLE)))
 352                 return 0;
 353         if (sgp->flags & GENHD_FL_SUPPRESS_PARTITION_INFO)
 354                 return 0;
 355
 356         /* show the full disk and all non-0 size partitions of it */
 357         seq_printf(part, "%4d  %4d %10llu %s\n",
 358                 sgp->major, sgp->first_minor,
 359                 (unsigned long long)get_capacity(sgp) >> 1,
 360                 disk_name(sgp, 0, buf));
 361         for (n = 0; n < sgp->minors - 1; n++) {
 362                 if (!sgp->part[n])
 363                         continue;
 364                 if (sgp->part[n]->nr_sects == 0)
 365                         continue;
 366                 seq_printf(part, "%4d  %4d %10llu %s\n",
 367                         sgp->major, n + 1 + sgp->first_minor,
 368                         (unsigned long long)sgp->part[n]->nr_sects >> 1 ,
 369                         disk_name(sgp, n + 1, buf));
 370         }
 371
 372         return 0;
 373 }
 374
 375 const struct seq_operations partitions_op = {
 376         .start  = part_start,
 377         .next   = part_next,
 378         .stop   = part_stop,
 379         .show   = show_partition
 380 };
 381 #endif
 382
 383
 384 static struct kobject *base_probe(dev_t devt, int *part, void *data)
 385 {
 386         if (request_module("block-major-%d-%d", MAJOR(devt), MINOR(devt)) > 0)
 387                 /* Make old-style 2.4 aliases work */
 388                 request_module("block-major-%d", MAJOR(devt));
 389         return NULL;
 390 }
 391
 392 static int __init genhd_device_init(void)
 393 {
 394         int error;
 395
 396         block_class.dev_kobj = sysfs_dev_block_kobj;
 397         error = class_register(&block_class);
 398         if (unlikely(error))
 399                 return error;
 400         bdev_map = kobj_map_init(base_probe, &block_class_lock);
 401         blk_dev_init();
 402
 403 #ifndef CONFIG_SYSFS_DEPRECATED
 404         /* create top-level block dir */
 405         block_depr = kobject_create_and_add("block", NULL);
 406 #endif
 407         return 0;
 408 }
 409
 410 subsys_initcall(genhd_device_init);
 411
 412 static ssize_t disk_range_show(struct device *dev,
 413                                struct device_attribute *attr, char *buf)
 414 {
 415         struct gendisk *disk = dev_to_disk(dev);
 416
 417         return sprintf(buf, "%d\n", disk->minors);
 418 }
 419
 420 static ssize_t disk_removable_show(struct device *dev,
 421                                    struct device_attribute *attr, char *buf)
 422 {
 423         struct gendisk *disk = dev_to_disk(dev);
 424
 425         return sprintf(buf, "%d\n",
 426                        (disk->flags & GENHD_FL_REMOVABLE ? 1 : 0));
 427 }
 428
 429 static ssize_t disk_ro_show(struct device *dev,
 430                                    struct device_attribute *attr, char *buf)
 431 {
 432         struct gendisk *disk = dev_to_disk(dev);
 433
 434         return sprintf(buf, "%d\n", disk->policy ? 1 : 0);
 435 }
 436
 437 static ssize_t disk_size_show(struct device *dev,
 438                               struct device_attribute *attr, char *buf)
 439 {
 440         struct gendisk *disk = dev_to_disk(dev);
 441
 442         return sprintf(buf, "%llu\n", (unsigned long long)get_capacity(disk));
 443 }
 444
 445 static ssize_t disk_capability_show(struct device *dev,
 446                                     struct device_attribute *attr, char *buf)
 447 {
 448         struct gendisk *disk = dev_to_disk(dev);
 449
 450         return sprintf(buf, "%x\n", disk->flags);
 451 }
 452
 453 static ssize_t disk_stat_show(struct device *dev,
 454                               struct device_attribute *attr, char *buf)
 455 {
 456         struct gendisk *disk = dev_to_disk(dev);
 457
 458         preempt_disable();
 459         disk_round_stats(disk);
 460         preempt_enable();
 461         return sprintf(buf,
 462                 "%8lu %8lu %8llu %8u "
 463                 "%8lu %8lu %8llu %8u "
 464                 "%8u %8u %8u"
 465                 "\n",
 466                 disk_stat_read(disk, ios[READ]),
 467                 disk_stat_read(disk, merges[READ]),
 468                 (unsigned long long)disk_stat_read(disk, sectors[READ]),
 469                 jiffies_to_msecs(disk_stat_read(disk, ticks[READ])),
 470                 disk_stat_read(disk, ios[WRITE]),
 471                 disk_stat_read(disk, merges[WRITE]),
 472                 (unsigned long long)disk_stat_read(disk, sectors[WRITE]),
 473                 jiffies_to_msecs(disk_stat_read(disk, ticks[WRITE])),
 474                 disk->in_flight,
 475                 jiffies_to_msecs(disk_stat_read(disk, io_ticks)),
 476                 jiffies_to_msecs(disk_stat_read(disk, time_in_queue)));
 477 }
 478
 479 #ifdef CONFIG_FAIL_MAKE_REQUEST
 480 static ssize_t disk_fail_show(struct device *dev,
 481                               struct device_attribute *attr, char *buf)
 482 {
 483         struct gendisk *disk = dev_to_disk(dev);
 484
 485         return sprintf(buf, "%d\n", disk->flags & GENHD_FL_FAIL ? 1 : 0);
 486 }
 487
 488 static ssize_t disk_fail_store(struct device *dev,
 489                                struct device_attribute *attr,
 490                                const char *buf, size_t count)
 491 {
 492         struct gendisk *disk = dev_to_disk(dev);
 493         int i;
 494
 495         if (count > 0 && sscanf(buf, "%d", &i) > 0) {
 496                 if (i == 0)
 497                         disk->flags &= ~GENHD_FL_FAIL;
 498                 else
 499                         disk->flags |= GENHD_FL_FAIL;
 500         }
 501
 502         return count;
 503 }
 504
 505 #endif
 506
 507 static DEVICE_ATTR(range, S_IRUGO, disk_range_show, NULL);
 508 static DEVICE_ATTR(removable, S_IRUGO, disk_removable_show, NULL);
 509 static DEVICE_ATTR(ro, S_IRUGO, disk_ro_show, NULL);
 510 static DEVICE_ATTR(size, S_IRUGO, disk_size_show, NULL);
 511 static DEVICE_ATTR(capability, S_IRUGO, disk_capability_show, NULL);
 512 static DEVICE_ATTR(stat, S_IRUGO, disk_stat_show, NULL);
 513 #ifdef CONFIG_FAIL_MAKE_REQUEST
 514 static struct device_attribute dev_attr_fail =
 515         __ATTR(make-it-fail, S_IRUGO|S_IWUSR, disk_fail_show, disk_fail_store);
 516 #endif
 517
 518 static struct attribute *disk_attrs[] = {
 519         &dev_attr_range.attr,
 520         &dev_attr_removable.attr,
 521         &dev_attr_ro.attr,
 522         &dev_attr_size.attr,
 523         &dev_attr_capability.attr,
 524         &dev_attr_stat.attr,
 525 #ifdef CONFIG_FAIL_MAKE_REQUEST
 526         &dev_attr_fail.attr,
 527 #endif
 528         NULL
 529 };
 530
 531 static struct attribute_group disk_attr_group = {
 532         .attrs = disk_attrs,
 533 };
 534
 535 static struct attribute_group *disk_attr_groups[] = {
 536         &disk_attr_group,
 537         NULL
 538 };
 539
 540 static void disk_release(struct device *dev)
 541 {
 542         struct gendisk *disk = dev_to_disk(dev);
 543
 544         kfree(disk->random);
 545         kfree(disk->part);
 546         free_disk_stats(disk);
 547         kfree(disk);
 548 }
 549 struct class block_class = {
 550         .name           = "block",
 551 };
 552
 553 static struct device_type disk_type = {
 554         .name           = "disk",
 555         .groups         = disk_attr_groups,
 556         .release        = disk_release,
 557 };
 558
 559 #ifdef CONFIG_PROC_FS
 560 /*
 561  * aggregate disk stat collector.  Uses the same stats that the sysfs
 562  * entries do, above, but makes them available through one seq_file.
 563  *
 564  * The output looks suspiciously like /proc/partitions with a bunch of
 565  * extra fields.
 566  */
 567
 568 static void *diskstats_start(struct seq_file *part, loff_t *pos)
 569 {
 570         struct device *dev;
 571
 572         mutex_lock(&block_class_lock);
 573         dev = class_find_device(&block_class, NULL, (void *)pos, find_start);
 574         if (dev)
 575                 return dev_to_disk(dev);
 576         return NULL;
 577 }
 578
 579 static void *diskstats_next(struct seq_file *part, void *v, loff_t *pos)
 580 {
 581         struct gendisk *gp = v;
 582         struct device *dev;
 583
 584         ++*pos;
 585         dev = class_find_device(&block_class, &gp->dev, NULL, find_next);
 586         if (dev)
 587                 return dev_to_disk(dev);
 588         return NULL;
 589 }
 590
 591 static void diskstats_stop(struct seq_file *part, void *v)
 592 {
 593         mutex_unlock(&block_class_lock);
 594 }
 595
 596 static int diskstats_show(struct seq_file *s, void *v)
 597 {
 598         struct gendisk *gp = v;
 599         char buf[BDEVNAME_SIZE];
 600         int n = 0;
 601
 602         /*
 603         if (&gp->dev.kobj.entry == block_class.devices.next)
 604                 seq_puts(s,     "major minor name"
 605                                 "     rio rmerge rsect ruse wio wmerge "
 606                                 "wsect wuse running use aveq"
 607                                 "\n\n");
 608         */
 609
 610         preempt_disable();
 611         disk_round_stats(gp);
 612         preempt_enable();
 613         seq_printf(s, "%4d %4d %s %lu %lu %llu %u %lu %lu %llu %u %u %u %u\n",
 614                 gp->major, n + gp->first_minor, disk_name(gp, n, buf),
 615                 disk_stat_read(gp, ios[0]), disk_stat_read(gp, merges[0]),
 616                 (unsigned long long)disk_stat_read(gp, sectors[0]),
 617                 jiffies_to_msecs(disk_stat_read(gp, ticks[0])),
 618                 disk_stat_read(gp, ios[1]), disk_stat_read(gp, merges[1]),
 619                 (unsigned long long)disk_stat_read(gp, sectors[1]),
 620                 jiffies_to_msecs(disk_stat_read(gp, ticks[1])),
 621                 gp->in_flight,
 622                 jiffies_to_msecs(disk_stat_read(gp, io_ticks)),
 623                 jiffies_to_msecs(disk_stat_read(gp, time_in_queue)));
 624
 625         /* now show all non-0 size partitions of it */
 626         for (n = 0; n < gp->minors - 1; n++) {
 627                 struct hd_struct *hd = gp->part[n];
 628
 629                 if (!hd || !hd->nr_sects)
 630                         continue;
 631
 632                 preempt_disable();
 633                 part_round_stats(hd);
 634                 preempt_enable();
 635                 seq_printf(s, "%4d %4d %s %lu %lu %llu "
 636                            "%u %lu %lu %llu %u %u %u %u\n",
 637                            gp->major, n + gp->first_minor + 1,
 638                            disk_name(gp, n + 1, buf),
 639                            part_stat_read(hd, ios[0]),
 640                            part_stat_read(hd, merges[0]),
 641                            (unsigned long long)part_stat_read(hd, sectors[0]),
 642                            jiffies_to_msecs(part_stat_read(hd, ticks[0])),
 643                            part_stat_read(hd, ios[1]),
 644                            part_stat_read(hd, merges[1]),
 645                            (unsigned long long)part_stat_read(hd, sectors[1]),
 646                            jiffies_to_msecs(part_stat_read(hd, ticks[1])),
 647                            hd->in_flight,
 648                            jiffies_to_msecs(part_stat_read(hd, io_ticks)),
 649                            jiffies_to_msecs(part_stat_read(hd, time_in_queue))
 650                         );
 651         }
 652
 653         return 0;
 654 }
 655
 656 const struct seq_operations diskstats_op = {
 657         .start  = diskstats_start,
 658         .next   = diskstats_next,
 659         .stop   = diskstats_stop,
 660         .show   = diskstats_show
 661 };
 662 #endif /* CONFIG_PROC_FS */
 663
 664 static void media_change_notify_thread(struct work_struct *work)
 665 {
 666         struct gendisk *gd = container_of(work, struct gendisk, async_notify);
 667         char event[] = "MEDIA_CHANGE=1";
 668         char *envp[] = { event, NULL };
 669
 670         /*
 671          * set enviroment vars to indicate which event this is for
 672          * so that user space will know to go check the media status.
 673          */
 674         kobject_uevent_env(&gd->dev.kobj, KOBJ_CHANGE, envp);
 675         put_device(gd->driverfs_dev);
 676 }
 677
 678 #if 0
 679 void genhd_media_change_notify(struct gendisk *disk)
 680 {
 681         get_device(disk->driverfs_dev);
 682         schedule_work(&disk->async_notify);
 683 }
 684 EXPORT_SYMBOL_GPL(genhd_media_change_notify);
 685 #endif  /*  0  */
 686
 687 struct find_block {
 688         const char *name;
 689         int part;
 690 };
 691
 692 static int match_id(struct device *dev, void *data)
 693 {
 694         struct find_block *find = data;
 695
 696         if (dev->type != &disk_type)
 697                 return 0;
 698         if (strcmp(dev->bus_id, find->name) == 0) {
 699                 struct gendisk *disk = dev_to_disk(dev);
 700                 if (find->part < disk->minors)
 701                         return 1;
 702         }
 703         return 0;
 704 }
 705
 706 dev_t blk_lookup_devt(const char *name, int part)
 707 {
 708         struct device *dev;
 709         dev_t devt = MKDEV(0, 0);
 710         struct find_block find;
 711
 712         mutex_lock(&block_class_lock);
 713         find.name = name;
 714         find.part = part;
 715         dev = class_find_device(&block_class, NULL, (void *)&find, match_id);
 716         if (dev)
 717                 devt = MKDEV(MAJOR(dev->devt),
 718                              MINOR(dev->devt) + part);
 719         mutex_unlock(&block_class_lock);
 720
 721         return devt;
 722 }
 723 EXPORT_SYMBOL(blk_lookup_devt);
 724
 725 struct gendisk *alloc_disk(int minors)
 726 {
 727         return alloc_disk_node(minors, -1);
 728 }
 729
 730 struct gendisk *alloc_disk_node(int minors, int node_id)
 731 {
 732         struct gendisk *disk;
 733
 734         disk = kmalloc_node(sizeof(struct gendisk),
 735                                 GFP_KERNEL | __GFP_ZERO, node_id);
 736         if (disk) {
 737                 if (!init_disk_stats(disk)) {
 738                         kfree(disk);
 739                         return NULL;
 740                 }
 741                 if (minors > 1) {
 742                         int size = (minors - 1) * sizeof(struct hd_struct *);
 743                         disk->part = kmalloc_node(size,
 744                                 GFP_KERNEL | __GFP_ZERO, node_id);
 745                         if (!disk->part) {
 746                                 free_disk_stats(disk);
 747                                 kfree(disk);
 748                                 return NULL;
 749                         }
 750                 }
 751                 disk->minors = minors;
 752                 rand_initialize_disk(disk);
 753                 disk->dev.class = &block_class;
 754                 disk->dev.type = &disk_type;
 755                 device_initialize(&disk->dev);
 756                 INIT_WORK(&disk->async_notify,
 757                         media_change_notify_thread);
 758         }
 759         return disk;
 760 }
 761
 762 EXPORT_SYMBOL(alloc_disk);
 763 EXPORT_SYMBOL(alloc_disk_node);
 764
 765 struct kobject *get_disk(struct gendisk *disk)
 766 {
 767         struct module *owner;
 768         struct kobject *kobj;
 769
 770         if (!disk->fops)
 771                 return NULL;
 772         owner = disk->fops->owner;
 773         if (owner && !try_module_get(owner))
 774                 return NULL;
 775         kobj = kobject_get(&disk->dev.kobj);
 776         if (kobj == NULL) {
 777                 module_put(owner);
 778                 return NULL;
 779         }
 780         return kobj;
 781
 782 }
 783
 784 EXPORT_SYMBOL(get_disk);
 785
 786 void put_disk(struct gendisk *disk)
 787 {
 788         if (disk)
 789                 kobject_put(&disk->dev.kobj);
 790 }
 791
 792 EXPORT_SYMBOL(put_disk);
 793
 794 void set_device_ro(struct block_device *bdev, int flag)
 795 {
 796         if (bdev->bd_contains != bdev)
 797                 bdev->bd_part->policy = flag;
 798         else
 799                 bdev->bd_disk->policy = flag;
 800 }
 801
 802 EXPORT_SYMBOL(set_device_ro);
 803
 804 void set_disk_ro(struct gendisk *disk, int flag)
 805 {
 806         int i;
 807         disk->policy = flag;
 808         for (i = 0; i < disk->minors - 1; i++)
 809                 if (disk->part[i]) disk->part[i]->policy = flag;
 810 }
 811
 812 EXPORT_SYMBOL(set_disk_ro);
 813
 814 int bdev_read_only(struct block_device *bdev)
 815 {
 816         if (!bdev)
 817                 return 0;
 818         else if (bdev->bd_contains != bdev)
 819                 return bdev->bd_part->policy;
 820         else
 821                 return bdev->bd_disk->policy;
 822 }
 823
 824 EXPORT_SYMBOL(bdev_read_only);
 825
 826 int invalidate_partition(struct gendisk *disk, int index)
 827 {
 828         int res = 0;
 829         struct block_device *bdev = bdget_disk(disk, index);
 830         if (bdev) {
 831                 fsync_bdev(bdev);
 832                 res = __invalidate_device(bdev);
 833                 bdput(bdev);
 834         }
 835         return res;
 836 }
 837
 838 EXPORT_SYMBOL(invalidate_partition);