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 #include <linux/idr.h>
  20
  21 #include "blk.h"
  22
  23 static DEFINE_MUTEX(block_class_lock);
  24 #ifndef CONFIG_SYSFS_DEPRECATED
  25 struct kobject *block_depr;
  26 #endif
  27
  28 /* for extended dynamic devt allocation, currently only one major is used */
  29 #define MAX_EXT_DEVT            (1 << MINORBITS)
  30
  31 /* For extended devt allocation.  ext_devt_mutex prevents look up
  32  * results from going away underneath its user.
  33  */
  34 static DEFINE_MUTEX(ext_devt_mutex);
  35 static DEFINE_IDR(ext_devt_idr);
  36
  37 static struct device_type disk_type;
  38
  39 /**
  40  * disk_get_part - get partition
  41  * @disk: disk to look partition from
  42  * @partno: partition number
  43  *
  44  * Look for partition @partno from @disk.  If found, increment
  45  * reference count and return it.
  46  *
  47  * CONTEXT:
  48  * Don't care.
  49  *
  50  * RETURNS:
  51  * Pointer to the found partition on success, NULL if not found.
  52  */
  53 struct hd_struct *disk_get_part(struct gendisk *disk, int partno)
  54 {
  55         struct hd_struct *part = NULL;
  56         struct disk_part_tbl *ptbl;
  57
  58         if (unlikely(partno < 0))
  59                 return NULL;
  60
  61         rcu_read_lock();
  62
  63         ptbl = rcu_dereference(disk->part_tbl);
  64         if (likely(partno < ptbl->len)) {
  65                 part = rcu_dereference(ptbl->part[partno]);
  66                 if (part)
  67                         get_device(part_to_dev(part));
  68         }
  69
  70         rcu_read_unlock();
  71
  72         return part;
  73 }
  74 EXPORT_SYMBOL_GPL(disk_get_part);
  75
  76 /**
  77  * disk_part_iter_init - initialize partition iterator
  78  * @piter: iterator to initialize
  79  * @disk: disk to iterate over
  80  * @flags: DISK_PITER_* flags
  81  *
  82  * Initialize @piter so that it iterates over partitions of @disk.
  83  *
  84  * CONTEXT:
  85  * Don't care.
  86  */
  87 void disk_part_iter_init(struct disk_part_iter *piter, struct gendisk *disk,
  88                           unsigned int flags)
  89 {
  90         struct disk_part_tbl *ptbl;
  91
  92         rcu_read_lock();
  93         ptbl = rcu_dereference(disk->part_tbl);
  94
  95         piter->disk = disk;
  96         piter->part = NULL;
  97
  98         if (flags & DISK_PITER_REVERSE)
  99                 piter->idx = ptbl->len - 1;
 100         else if (flags & DISK_PITER_INCL_PART0)
 101                 piter->idx = 0;
 102         else
 103                 piter->idx = 1;
 104
 105         piter->flags = flags;
 106
 107         rcu_read_unlock();
 108 }
 109 EXPORT_SYMBOL_GPL(disk_part_iter_init);
 110
 111 /**
 112  * disk_part_iter_next - proceed iterator to the next partition and return it
 113  * @piter: iterator of interest
 114  *
 115  * Proceed @piter to the next partition and return it.
 116  *
 117  * CONTEXT:
 118  * Don't care.
 119  */
 120 struct hd_struct *disk_part_iter_next(struct disk_part_iter *piter)
 121 {
 122         struct disk_part_tbl *ptbl;
 123         int inc, end;
 124
 125         /* put the last partition */
 126         disk_put_part(piter->part);
 127         piter->part = NULL;
 128
 129         /* get part_tbl */
 130         rcu_read_lock();
 131         ptbl = rcu_dereference(piter->disk->part_tbl);
 132
 133         /* determine iteration parameters */
 134         if (piter->flags & DISK_PITER_REVERSE) {
 135                 inc = -1;
 136                 if (piter->flags & DISK_PITER_INCL_PART0)
 137                         end = -1;
 138                 else
 139                         end = 0;
 140         } else {
 141                 inc = 1;
 142                 end = ptbl->len;
 143         }
 144
 145         /* iterate to the next partition */
 146         for (; piter->idx != end; piter->idx += inc) {
 147                 struct hd_struct *part;
 148
 149                 part = rcu_dereference(ptbl->part[piter->idx]);
 150                 if (!part)
 151                         continue;
 152                 if (!(piter->flags & DISK_PITER_INCL_EMPTY) && !part->nr_sects)
 153                         continue;
 154
 155                 get_device(part_to_dev(part));
 156                 piter->part = part;
 157                 piter->idx += inc;
 158                 break;
 159         }
 160
 161         rcu_read_unlock();
 162
 163         return piter->part;
 164 }
 165 EXPORT_SYMBOL_GPL(disk_part_iter_next);
 166
 167 /**
 168  * disk_part_iter_exit - finish up partition iteration
 169  * @piter: iter of interest
 170  *
 171  * Called when iteration is over.  Cleans up @piter.
 172  *
 173  * CONTEXT:
 174  * Don't care.
 175  */
 176 void disk_part_iter_exit(struct disk_part_iter *piter)
 177 {
 178         disk_put_part(piter->part);
 179         piter->part = NULL;
 180 }
 181 EXPORT_SYMBOL_GPL(disk_part_iter_exit);
 182
 183 /**
 184  * disk_map_sector_rcu - map sector to partition
 185  * @disk: gendisk of interest
 186  * @sector: sector to map
 187  *
 188  * Find out which partition @sector maps to on @disk.  This is
 189  * primarily used for stats accounting.
 190  *
 191  * CONTEXT:
 192  * RCU read locked.  The returned partition pointer is valid only
 193  * while preemption is disabled.
 194  *
 195  * RETURNS:
 196  * Found partition on success, part0 is returned if no partition matches
 197  */
 198 struct hd_struct *disk_map_sector_rcu(struct gendisk *disk, sector_t sector)
 199 {
 200         struct disk_part_tbl *ptbl;
 201         int i;
 202
 203         ptbl = rcu_dereference(disk->part_tbl);
 204
 205         for (i = 1; i < ptbl->len; i++) {
 206                 struct hd_struct *part = rcu_dereference(ptbl->part[i]);
 207
 208                 if (part && part->start_sect <= sector &&
 209                     sector < part->start_sect + part->nr_sects)
 210                         return part;
 211         }
 212         return &disk->part0;
 213 }
 214 EXPORT_SYMBOL_GPL(disk_map_sector_rcu);
 215
 216 /*
 217  * Can be deleted altogether. Later.
 218  *
 219  */
 220 static struct blk_major_name {
 221         struct blk_major_name *next;
 222         int major;
 223         char name[16];
 224 } *major_names[BLKDEV_MAJOR_HASH_SIZE];
 225
 226 /* index in the above - for now: assume no multimajor ranges */
 227 static inline int major_to_index(int major)
 228 {
 229         return major % BLKDEV_MAJOR_HASH_SIZE;
 230 }
 231
 232 #ifdef CONFIG_PROC_FS
 233 void blkdev_show(struct seq_file *seqf, off_t offset)
 234 {
 235         struct blk_major_name *dp;
 236
 237         if (offset < BLKDEV_MAJOR_HASH_SIZE) {
 238                 mutex_lock(&block_class_lock);
 239                 for (dp = major_names[offset]; dp; dp = dp->next)
 240                         seq_printf(seqf, "%3d %s\n", dp->major, dp->name);
 241                 mutex_unlock(&block_class_lock);
 242         }
 243 }
 244 #endif /* CONFIG_PROC_FS */
 245
 246 int register_blkdev(unsigned int major, const char *name)
 247 {
 248         struct blk_major_name **n, *p;
 249         int index, ret = 0;
 250
 251         mutex_lock(&block_class_lock);
 252
 253         /* temporary */
 254         if (major == 0) {
 255                 for (index = ARRAY_SIZE(major_names)-1; index > 0; index--) {
 256                         if (major_names[index] == NULL)
 257                                 break;
 258                 }
 259
 260                 if (index == 0) {
 261                         printk("register_blkdev: failed to get major for %s\n",
 262                                name);
 263                         ret = -EBUSY;
 264                         goto out;
 265                 }
 266                 major = index;
 267                 ret = major;
 268         }
 269
 270         p = kmalloc(sizeof(struct blk_major_name), GFP_KERNEL);
 271         if (p == NULL) {
 272                 ret = -ENOMEM;
 273                 goto out;
 274         }
 275
 276         p->major = major;
 277         strlcpy(p->name, name, sizeof(p->name));
 278         p->next = NULL;
 279         index = major_to_index(major);
 280
 281         for (n = &major_names[index]; *n; n = &(*n)->next) {
 282                 if ((*n)->major == major)
 283                         break;
 284         }
 285         if (!*n)
 286                 *n = p;
 287         else
 288                 ret = -EBUSY;
 289
 290         if (ret < 0) {
 291                 printk("register_blkdev: cannot get major %d for %s\n",
 292                        major, name);
 293                 kfree(p);
 294         }
 295 out:
 296         mutex_unlock(&block_class_lock);
 297         return ret;
 298 }
 299
 300 EXPORT_SYMBOL(register_blkdev);
 301
 302 void unregister_blkdev(unsigned int major, const char *name)
 303 {
 304         struct blk_major_name **n;
 305         struct blk_major_name *p = NULL;
 306         int index = major_to_index(major);
 307
 308         mutex_lock(&block_class_lock);
 309         for (n = &major_names[index]; *n; n = &(*n)->next)
 310                 if ((*n)->major == major)
 311                         break;
 312         if (!*n || strcmp((*n)->name, name)) {
 313                 WARN_ON(1);
 314         } else {
 315                 p = *n;
 316                 *n = p->next;
 317         }
 318         mutex_unlock(&block_class_lock);
 319         kfree(p);
 320 }
 321
 322 EXPORT_SYMBOL(unregister_blkdev);
 323
 324 static struct kobj_map *bdev_map;
 325
 326 /**
 327  * blk_mangle_minor - scatter minor numbers apart
 328  * @minor: minor number to mangle
 329  *
 330  * Scatter consecutively allocated @minor number apart if MANGLE_DEVT
 331  * is enabled.  Mangling twice gives the original value.
 332  *
 333  * RETURNS:
 334  * Mangled value.
 335  *
 336  * CONTEXT:
 337  * Don't care.
 338  */
 339 static int blk_mangle_minor(int minor)
 340 {
 341 #ifdef CONFIG_DEBUG_BLOCK_EXT_DEVT
 342         int i;
 343
 344         for (i = 0; i < MINORBITS / 2; i++) {
 345                 int low = minor & (1 << i);
 346                 int high = minor & (1 << (MINORBITS - 1 - i));
 347                 int distance = MINORBITS - 1 - 2 * i;
 348
 349                 minor ^= low | high;    /* clear both bits */
 350                 low <<= distance;       /* swap the positions */
 351                 high >>= distance;
 352                 minor |= low | high;    /* and set */
 353         }
 354 #endif
 355         return minor;
 356 }
 357
 358 /**
 359  * blk_alloc_devt - allocate a dev_t for a partition
 360  * @part: partition to allocate dev_t for
 361  * @gfp_mask: memory allocation flag
 362  * @devt: out parameter for resulting dev_t
 363  *
 364  * Allocate a dev_t for block device.
 365  *
 366  * RETURNS:
 367  * 0 on success, allocated dev_t is returned in *@devt.  -errno on
 368  * failure.
 369  *
 370  * CONTEXT:
 371  * Might sleep.
 372  */
 373 int blk_alloc_devt(struct hd_struct *part, dev_t *devt)
 374 {
 375         struct gendisk *disk = part_to_disk(part);
 376         int idx, rc;
 377
 378         /* in consecutive minor range? */
 379         if (part->partno < disk->minors) {
 380                 *devt = MKDEV(disk->major, disk->first_minor + part->partno);
 381                 return 0;
 382         }
 383
 384         /* allocate ext devt */
 385         do {
 386                 if (!idr_pre_get(&ext_devt_idr, GFP_KERNEL))
 387                         return -ENOMEM;
 388                 rc = idr_get_new(&ext_devt_idr, part, &idx);
 389         } while (rc == -EAGAIN);
 390
 391         if (rc)
 392                 return rc;
 393
 394         if (idx > MAX_EXT_DEVT) {
 395                 idr_remove(&ext_devt_idr, idx);
 396                 return -EBUSY;
 397         }
 398
 399         *devt = MKDEV(BLOCK_EXT_MAJOR, blk_mangle_minor(idx));
 400         return 0;
 401 }
 402
 403 /**
 404  * blk_free_devt - free a dev_t
 405  * @devt: dev_t to free
 406  *
 407  * Free @devt which was allocated using blk_alloc_devt().
 408  *
 409  * CONTEXT:
 410  * Might sleep.
 411  */
 412 void blk_free_devt(dev_t devt)
 413 {
 414         might_sleep();
 415
 416         if (devt == MKDEV(0, 0))
 417                 return;
 418
 419         if (MAJOR(devt) == BLOCK_EXT_MAJOR) {
 420                 mutex_lock(&ext_devt_mutex);
 421                 idr_remove(&ext_devt_idr, blk_mangle_minor(MINOR(devt)));
 422                 mutex_unlock(&ext_devt_mutex);
 423         }
 424 }
 425
 426 static char *bdevt_str(dev_t devt, char *buf)
 427 {
 428         if (MAJOR(devt) <= 0xff && MINOR(devt) <= 0xff) {
 429                 char tbuf[BDEVT_SIZE];
 430                 snprintf(tbuf, BDEVT_SIZE, "%02x%02x", MAJOR(devt), MINOR(devt));
 431                 snprintf(buf, BDEVT_SIZE, "%-9s", tbuf);
 432         } else
 433                 snprintf(buf, BDEVT_SIZE, "%03x:%05x", MAJOR(devt), MINOR(devt));
 434
 435         return buf;
 436 }
 437
 438 /*
 439  * Register device numbers dev..(dev+range-1)
 440  * range must be nonzero
 441  * The hash chain is sorted on range, so that subranges can override.
 442  */
 443 void blk_register_region(dev_t devt, unsigned long range, struct module *module,
 444                          struct kobject *(*probe)(dev_t, int *, void *),
 445                          int (*lock)(dev_t, void *), void *data)
 446 {
 447         kobj_map(bdev_map, devt, range, module, probe, lock, data);
 448 }
 449
 450 EXPORT_SYMBOL(blk_register_region);
 451
 452 void blk_unregister_region(dev_t devt, unsigned long range)
 453 {
 454         kobj_unmap(bdev_map, devt, range);
 455 }
 456
 457 EXPORT_SYMBOL(blk_unregister_region);
 458
 459 static struct kobject *exact_match(dev_t devt, int *partno, void *data)
 460 {
 461         struct gendisk *p = data;
 462
 463         return &disk_to_dev(p)->kobj;
 464 }
 465
 466 static int exact_lock(dev_t devt, void *data)
 467 {
 468         struct gendisk *p = data;
 469
 470         if (!get_disk(p))
 471                 return -1;
 472         return 0;
 473 }
 474
 475 /**
 476  * add_disk - add partitioning information to kernel list
 477  * @disk: per-device partitioning information
 478  *
 479  * This function registers the partitioning information in @disk
 480  * with the kernel.
 481  *
 482  * FIXME: error handling
 483  */
 484 void add_disk(struct gendisk *disk)
 485 {
 486         struct backing_dev_info *bdi;
 487         dev_t devt;
 488         int retval;
 489
 490         /* minors == 0 indicates to use ext devt from part0 and should
 491          * be accompanied with EXT_DEVT flag.  Make sure all
 492          * parameters make sense.
 493          */
 494         WARN_ON(disk->minors && !(disk->major || disk->first_minor));
 495         WARN_ON(!disk->minors && !(disk->flags & GENHD_FL_EXT_DEVT));
 496
 497         disk->flags |= GENHD_FL_UP;
 498
 499         retval = blk_alloc_devt(&disk->part0, &devt);
 500         if (retval) {
 501                 WARN_ON(1);
 502                 return;
 503         }
 504         disk_to_dev(disk)->devt = devt;
 505
 506         /* ->major and ->first_minor aren't supposed to be
 507          * dereferenced from here on, but set them just in case.
 508          */
 509         disk->major = MAJOR(devt);
 510         disk->first_minor = MINOR(devt);
 511
 512         blk_register_region(disk_devt(disk), disk->minors, NULL,
 513                             exact_match, exact_lock, disk);
 514         register_disk(disk);
 515         blk_register_queue(disk);
 516
 517         bdi = &disk->queue->backing_dev_info;
 518         bdi_register_dev(bdi, disk_devt(disk));
 519         retval = sysfs_create_link(&disk_to_dev(disk)->kobj, &bdi->dev->kobj,
 520                                    "bdi");
 521         WARN_ON(retval);
 522 }
 523
 524 EXPORT_SYMBOL(add_disk);
 525 EXPORT_SYMBOL(del_gendisk);     /* in partitions/check.c */
 526
 527 void unlink_gendisk(struct gendisk *disk)
 528 {
 529         sysfs_remove_link(&disk_to_dev(disk)->kobj, "bdi");
 530         bdi_unregister(&disk->queue->backing_dev_info);
 531         blk_unregister_queue(disk);
 532         blk_unregister_region(disk_devt(disk), disk->minors);
 533 }
 534
 535 /**
 536  * get_gendisk - get partitioning information for a given device
 537  * @devt: device to get partitioning information for
 538  * @part: returned partition index
 539  *
 540  * This function gets the structure containing partitioning
 541  * information for the given device @devt.
 542  */
 543 struct gendisk *get_gendisk(dev_t devt, int *partno)
 544 {
 545         struct gendisk *disk = NULL;
 546
 547         if (MAJOR(devt) != BLOCK_EXT_MAJOR) {
 548                 struct kobject *kobj;
 549
 550                 kobj = kobj_lookup(bdev_map, devt, partno);
 551                 if (kobj)
 552                         disk = dev_to_disk(kobj_to_dev(kobj));
 553         } else {
 554                 struct hd_struct *part;
 555
 556                 mutex_lock(&ext_devt_mutex);
 557                 part = idr_find(&ext_devt_idr, blk_mangle_minor(MINOR(devt)));
 558                 if (part && get_disk(part_to_disk(part))) {
 559                         *partno = part->partno;
 560                         disk = part_to_disk(part);
 561                 }
 562                 mutex_unlock(&ext_devt_mutex);
 563         }
 564
 565         return disk;
 566 }
 567
 568 /**
 569  * bdget_disk - do bdget() by gendisk and partition number
 570  * @disk: gendisk of interest
 571  * @partno: partition number
 572  *
 573  * Find partition @partno from @disk, do bdget() on it.
 574  *
 575  * CONTEXT:
 576  * Don't care.
 577  *
 578  * RETURNS:
 579  * Resulting block_device on success, NULL on failure.
 580  */
 581 struct block_device *bdget_disk(struct gendisk *disk, int partno)
 582 {
 583         struct hd_struct *part;
 584         struct block_device *bdev = NULL;
 585
 586         part = disk_get_part(disk, partno);
 587         if (part)
 588                 bdev = bdget(part_devt(part));
 589         disk_put_part(part);
 590
 591         return bdev;
 592 }
 593 EXPORT_SYMBOL(bdget_disk);
 594
 595 /*
 596  * print a full list of all partitions - intended for places where the root
 597  * filesystem can't be mounted and thus to give the victim some idea of what
 598  * went wrong
 599  */
 600 void __init printk_all_partitions(void)
 601 {
 602         struct class_dev_iter iter;
 603         struct device *dev;
 604
 605         class_dev_iter_init(&iter, &block_class, NULL, &disk_type);
 606         while ((dev = class_dev_iter_next(&iter))) {
 607                 struct gendisk *disk = dev_to_disk(dev);
 608                 struct disk_part_iter piter;
 609                 struct hd_struct *part;
 610                 char name_buf[BDEVNAME_SIZE];
 611                 char devt_buf[BDEVT_SIZE];
 612
 613                 /*
 614                  * Don't show empty devices or things that have been
 615                  * surpressed
 616                  */
 617                 if (get_capacity(disk) == 0 ||
 618                     (disk->flags & GENHD_FL_SUPPRESS_PARTITION_INFO))
 619                         continue;
 620
 621                 /*
 622                  * Note, unlike /proc/partitions, I am showing the
 623                  * numbers in hex - the same format as the root=
 624                  * option takes.
 625                  */
 626                 disk_part_iter_init(&piter, disk, DISK_PITER_INCL_PART0);
 627                 while ((part = disk_part_iter_next(&piter))) {
 628                         bool is_part0 = part == &disk->part0;
 629
 630                         printk("%s%s %10llu %s", is_part0 ? "" : "  ",
 631                                bdevt_str(part_devt(part), devt_buf),
 632                                (unsigned long long)part->nr_sects >> 1,
 633                                disk_name(disk, part->partno, name_buf));
 634                         if (is_part0) {
 635                                 if (disk->driverfs_dev != NULL &&
 636                                     disk->driverfs_dev->driver != NULL)
 637                                         printk(" driver: %s\n",
 638                                               disk->driverfs_dev->driver->name);
 639                                 else
 640                                         printk(" (driver?)\n");
 641                         } else
 642                                 printk("\n");
 643                 }
 644                 disk_part_iter_exit(&piter);
 645         }
 646         class_dev_iter_exit(&iter);
 647 }
 648
 649 #ifdef CONFIG_PROC_FS
 650 /* iterator */
 651 static void *disk_seqf_start(struct seq_file *seqf, loff_t *pos)
 652 {
 653         loff_t skip = *pos;
 654         struct class_dev_iter *iter;
 655         struct device *dev;
 656
 657         iter = kmalloc(sizeof(*iter), GFP_KERNEL);
 658         if (!iter)
 659                 return ERR_PTR(-ENOMEM);
 660
 661         seqf->private = iter;
 662         class_dev_iter_init(iter, &block_class, NULL, &disk_type);
 663         do {
 664                 dev = class_dev_iter_next(iter);
 665                 if (!dev)
 666                         return NULL;
 667         } while (skip--);
 668
 669         return dev_to_disk(dev);
 670 }
 671
 672 static void *disk_seqf_next(struct seq_file *seqf, void *v, loff_t *pos)
 673 {
 674         struct device *dev;
 675
 676         (*pos)++;
 677         dev = class_dev_iter_next(seqf->private);
 678         if (dev)
 679                 return dev_to_disk(dev);
 680
 681         return NULL;
 682 }
 683
 684 static void disk_seqf_stop(struct seq_file *seqf, void *v)
 685 {
 686         struct class_dev_iter *iter = seqf->private;
 687
 688         /* stop is called even after start failed :-( */
 689         if (iter) {
 690                 class_dev_iter_exit(iter);
 691                 kfree(iter);
 692         }
 693 }
 694
 695 static void *show_partition_start(struct seq_file *seqf, loff_t *pos)
 696 {
 697         static void *p;
 698
 699         p = disk_seqf_start(seqf, pos);
 700         if (!IS_ERR(p) && p && !*pos)
 701                 seq_puts(seqf, "major minor  #blocks  name\n\n");
 702         return p;
 703 }
 704
 705 static int show_partition(struct seq_file *seqf, void *v)
 706 {
 707         struct gendisk *sgp = v;
 708         struct disk_part_iter piter;
 709         struct hd_struct *part;
 710         char buf[BDEVNAME_SIZE];
 711
 712         /* Don't show non-partitionable removeable devices or empty devices */
 713         if (!get_capacity(sgp) || (!disk_partitionable(sgp) &&
 714                                    (sgp->flags & GENHD_FL_REMOVABLE)))
 715                 return 0;
 716         if (sgp->flags & GENHD_FL_SUPPRESS_PARTITION_INFO)
 717                 return 0;
 718
 719         /* show the full disk and all non-0 size partitions of it */
 720         disk_part_iter_init(&piter, sgp, DISK_PITER_INCL_PART0);
 721         while ((part = disk_part_iter_next(&piter)))
 722                 seq_printf(seqf, "%4d  %7d %10llu %s\n",
 723                            MAJOR(part_devt(part)), MINOR(part_devt(part)),
 724                            (unsigned long long)part->nr_sects >> 1,
 725                            disk_name(sgp, part->partno, buf));
 726         disk_part_iter_exit(&piter);
 727
 728         return 0;
 729 }
 730
 731 const struct seq_operations partitions_op = {
 732         .start  = show_partition_start,
 733         .next   = disk_seqf_next,
 734         .stop   = disk_seqf_stop,
 735         .show   = show_partition
 736 };
 737 #endif
 738
 739
 740 static struct kobject *base_probe(dev_t devt, int *partno, void *data)
 741 {
 742         if (request_module("block-major-%d-%d", MAJOR(devt), MINOR(devt)) > 0)
 743                 /* Make old-style 2.4 aliases work */
 744                 request_module("block-major-%d", MAJOR(devt));
 745         return NULL;
 746 }
 747
 748 static int __init genhd_device_init(void)
 749 {
 750         int error;
 751
 752         block_class.dev_kobj = sysfs_dev_block_kobj;
 753         error = class_register(&block_class);
 754         if (unlikely(error))
 755                 return error;
 756         bdev_map = kobj_map_init(base_probe, &block_class_lock);
 757         blk_dev_init();
 758
 759 #ifndef CONFIG_SYSFS_DEPRECATED
 760         /* create top-level block dir */
 761         block_depr = kobject_create_and_add("block", NULL);
 762 #endif
 763         return 0;
 764 }
 765
 766 subsys_initcall(genhd_device_init);
 767
 768 static ssize_t disk_range_show(struct device *dev,
 769                                struct device_attribute *attr, char *buf)
 770 {
 771         struct gendisk *disk = dev_to_disk(dev);
 772
 773         return sprintf(buf, "%d\n", disk->minors);
 774 }
 775
 776 static ssize_t disk_ext_range_show(struct device *dev,
 777                                    struct device_attribute *attr, char *buf)
 778 {
 779         struct gendisk *disk = dev_to_disk(dev);
 780
 781         return sprintf(buf, "%d\n", disk_max_parts(disk));
 782 }
 783
 784 static ssize_t disk_removable_show(struct device *dev,
 785                                    struct device_attribute *attr, char *buf)
 786 {
 787         struct gendisk *disk = dev_to_disk(dev);
 788
 789         return sprintf(buf, "%d\n",
 790                        (disk->flags & GENHD_FL_REMOVABLE ? 1 : 0));
 791 }
 792
 793 static ssize_t disk_ro_show(struct device *dev,
 794                                    struct device_attribute *attr, char *buf)
 795 {
 796         struct gendisk *disk = dev_to_disk(dev);
 797
 798         return sprintf(buf, "%d\n", get_disk_ro(disk) ? 1 : 0);
 799 }
 800
 801 static ssize_t disk_capability_show(struct device *dev,
 802                                     struct device_attribute *attr, char *buf)
 803 {
 804         struct gendisk *disk = dev_to_disk(dev);
 805
 806         return sprintf(buf, "%x\n", disk->flags);
 807 }
 808
 809 static DEVICE_ATTR(range, S_IRUGO, disk_range_show, NULL);
 810 static DEVICE_ATTR(ext_range, S_IRUGO, disk_ext_range_show, NULL);
 811 static DEVICE_ATTR(removable, S_IRUGO, disk_removable_show, NULL);
 812 static DEVICE_ATTR(ro, S_IRUGO, disk_ro_show, NULL);
 813 static DEVICE_ATTR(size, S_IRUGO, part_size_show, NULL);
 814 static DEVICE_ATTR(capability, S_IRUGO, disk_capability_show, NULL);
 815 static DEVICE_ATTR(stat, S_IRUGO, part_stat_show, NULL);
 816 #ifdef CONFIG_FAIL_MAKE_REQUEST
 817 static struct device_attribute dev_attr_fail =
 818         __ATTR(make-it-fail, S_IRUGO|S_IWUSR, part_fail_show, part_fail_store);
 819 #endif
 820 #ifdef CONFIG_FAIL_IO_TIMEOUT
 821 static struct device_attribute dev_attr_fail_timeout =
 822         __ATTR(io-timeout-fail,  S_IRUGO|S_IWUSR, part_timeout_show,
 823                 part_timeout_store);
 824 #endif
 825
 826 static struct attribute *disk_attrs[] = {
 827         &dev_attr_range.attr,
 828         &dev_attr_ext_range.attr,
 829         &dev_attr_removable.attr,
 830         &dev_attr_ro.attr,
 831         &dev_attr_size.attr,
 832         &dev_attr_capability.attr,
 833         &dev_attr_stat.attr,
 834 #ifdef CONFIG_FAIL_MAKE_REQUEST
 835         &dev_attr_fail.attr,
 836 #endif
 837 #ifdef CONFIG_FAIL_IO_TIMEOUT
 838         &dev_attr_fail_timeout.attr,
 839 #endif
 840         NULL
 841 };
 842
 843 static struct attribute_group disk_attr_group = {
 844         .attrs = disk_attrs,
 845 };
 846
 847 static struct attribute_group *disk_attr_groups[] = {
 848         &disk_attr_group,
 849         NULL
 850 };
 851
 852 static void disk_free_ptbl_rcu_cb(struct rcu_head *head)
 853 {
 854         struct disk_part_tbl *ptbl =
 855                 container_of(head, struct disk_part_tbl, rcu_head);
 856
 857         kfree(ptbl);
 858 }
 859
 860 /**
 861  * disk_replace_part_tbl - replace disk->part_tbl in RCU-safe way
 862  * @disk: disk to replace part_tbl for
 863  * @new_ptbl: new part_tbl to install
 864  *
 865  * Replace disk->part_tbl with @new_ptbl in RCU-safe way.  The
 866  * original ptbl is freed using RCU callback.
 867  *
 868  * LOCKING:
 869  * Matching bd_mutx locked.
 870  */
 871 static void disk_replace_part_tbl(struct gendisk *disk,
 872                                   struct disk_part_tbl *new_ptbl)
 873 {
 874         struct disk_part_tbl *old_ptbl = disk->part_tbl;
 875
 876         rcu_assign_pointer(disk->part_tbl, new_ptbl);
 877         if (old_ptbl)
 878                 call_rcu(&old_ptbl->rcu_head, disk_free_ptbl_rcu_cb);
 879 }
 880
 881 /**
 882  * disk_expand_part_tbl - expand disk->part_tbl
 883  * @disk: disk to expand part_tbl for
 884  * @partno: expand such that this partno can fit in
 885  *
 886  * Expand disk->part_tbl such that @partno can fit in.  disk->part_tbl
 887  * uses RCU to allow unlocked dereferencing for stats and other stuff.
 888  *
 889  * LOCKING:
 890  * Matching bd_mutex locked, might sleep.
 891  *
 892  * RETURNS:
 893  * 0 on success, -errno on failure.
 894  */
 895 int disk_expand_part_tbl(struct gendisk *disk, int partno)
 896 {
 897         struct disk_part_tbl *old_ptbl = disk->part_tbl;
 898         struct disk_part_tbl *new_ptbl;
 899         int len = old_ptbl ? old_ptbl->len : 0;
 900         int target = partno + 1;
 901         size_t size;
 902         int i;
 903
 904         /* disk_max_parts() is zero during initialization, ignore if so */
 905         if (disk_max_parts(disk) && target > disk_max_parts(disk))
 906                 return -EINVAL;
 907
 908         if (target <= len)
 909                 return 0;
 910
 911         size = sizeof(*new_ptbl) + target * sizeof(new_ptbl->part[0]);
 912         new_ptbl = kzalloc_node(size, GFP_KERNEL, disk->node_id);
 913         if (!new_ptbl)
 914                 return -ENOMEM;
 915
 916         INIT_RCU_HEAD(&new_ptbl->rcu_head);
 917         new_ptbl->len = target;
 918
 919         for (i = 0; i < len; i++)
 920                 rcu_assign_pointer(new_ptbl->part[i], old_ptbl->part[i]);
 921
 922         disk_replace_part_tbl(disk, new_ptbl);
 923         return 0;
 924 }
 925
 926 static void disk_release(struct device *dev)
 927 {
 928         struct gendisk *disk = dev_to_disk(dev);
 929
 930         kfree(disk->random);
 931         disk_replace_part_tbl(disk, NULL);
 932         free_part_stats(&disk->part0);
 933         kfree(disk);
 934 }
 935 struct class block_class = {
 936         .name           = "block",
 937 };
 938
 939 static struct device_type disk_type = {
 940         .name           = "disk",
 941         .groups         = disk_attr_groups,
 942         .release        = disk_release,
 943 };
 944
 945 #ifdef CONFIG_PROC_FS
 946 /*
 947  * aggregate disk stat collector.  Uses the same stats that the sysfs
 948  * entries do, above, but makes them available through one seq_file.
 949  *
 950  * The output looks suspiciously like /proc/partitions with a bunch of
 951  * extra fields.
 952  */
 953 static int diskstats_show(struct seq_file *seqf, void *v)
 954 {
 955         struct gendisk *gp = v;
 956         struct disk_part_iter piter;
 957         struct hd_struct *hd;
 958         char buf[BDEVNAME_SIZE];
 959         int cpu;
 960
 961         /*
 962         if (&disk_to_dev(gp)->kobj.entry == block_class.devices.next)
 963                 seq_puts(seqf,  "major minor name"
 964                                 "     rio rmerge rsect ruse wio wmerge "
 965                                 "wsect wuse running use aveq"
 966                                 "\n\n");
 967         */
 968
 969         disk_part_iter_init(&piter, gp, DISK_PITER_INCL_PART0);
 970         while ((hd = disk_part_iter_next(&piter))) {
 971                 cpu = part_stat_lock();
 972                 part_round_stats(cpu, hd);
 973                 part_stat_unlock();
 974                 seq_printf(seqf, "%4d %7d %s %lu %lu %llu "
 975                            "%u %lu %lu %llu %u %u %u %u\n",
 976                            MAJOR(part_devt(hd)), MINOR(part_devt(hd)),
 977                            disk_name(gp, hd->partno, buf),
 978                            part_stat_read(hd, ios[0]),
 979                            part_stat_read(hd, merges[0]),
 980                            (unsigned long long)part_stat_read(hd, sectors[0]),
 981                            jiffies_to_msecs(part_stat_read(hd, ticks[0])),
 982                            part_stat_read(hd, ios[1]),
 983                            part_stat_read(hd, merges[1]),
 984                            (unsigned long long)part_stat_read(hd, sectors[1]),
 985                            jiffies_to_msecs(part_stat_read(hd, ticks[1])),
 986                            hd->in_flight,
 987                            jiffies_to_msecs(part_stat_read(hd, io_ticks)),
 988                            jiffies_to_msecs(part_stat_read(hd, time_in_queue))
 989                         );
 990         }
 991         disk_part_iter_exit(&piter);
 992
 993         return 0;
 994 }
 995
 996 const struct seq_operations diskstats_op = {
 997         .start  = disk_seqf_start,
 998         .next   = disk_seqf_next,
 999         .stop   = disk_seqf_stop,
1000         .show   = diskstats_show
1001 };
1002 #endif /* CONFIG_PROC_FS */
1003
1004 static void media_change_notify_thread(struct work_struct *work)
1005 {
1006         struct gendisk *gd = container_of(work, struct gendisk, async_notify);
1007         char event[] = "MEDIA_CHANGE=1";
1008         char *envp[] = { event, NULL };
1009
1010         /*
1011          * set enviroment vars to indicate which event this is for
1012          * so that user space will know to go check the media status.
1013          */
1014         kobject_uevent_env(&disk_to_dev(gd)->kobj, KOBJ_CHANGE, envp);
1015         put_device(gd->driverfs_dev);
1016 }
1017
1018 #if 0
1019 void genhd_media_change_notify(struct gendisk *disk)
1020 {
1021         get_device(disk->driverfs_dev);
1022         schedule_work(&disk->async_notify);
1023 }
1024 EXPORT_SYMBOL_GPL(genhd_media_change_notify);
1025 #endif  /*  0  */
1026
1027 dev_t blk_lookup_devt(const char *name, int partno)
1028 {
1029         dev_t devt = MKDEV(0, 0);
1030         struct class_dev_iter iter;
1031         struct device *dev;
1032
1033         class_dev_iter_init(&iter, &block_class, NULL, &disk_type);
1034         while ((dev = class_dev_iter_next(&iter))) {
1035                 struct gendisk *disk = dev_to_disk(dev);
1036                 struct hd_struct *part;
1037
1038                 if (strcmp(dev->bus_id, name))
1039                         continue;
1040
1041                 part = disk_get_part(disk, partno);
1042                 if (part) {
1043                         devt = part_devt(part);
1044                         disk_put_part(part);
1045                         break;
1046                 }
1047                 disk_put_part(part);
1048         }
1049         class_dev_iter_exit(&iter);
1050         return devt;
1051 }
1052 EXPORT_SYMBOL(blk_lookup_devt);
1053
1054 struct gendisk *alloc_disk(int minors)
1055 {
1056         return alloc_disk_node(minors, -1);
1057 }
1058 EXPORT_SYMBOL(alloc_disk);
1059
1060 struct gendisk *alloc_disk_node(int minors, int node_id)
1061 {
1062         struct gendisk *disk;
1063
1064         disk = kmalloc_node(sizeof(struct gendisk),
1065                                 GFP_KERNEL | __GFP_ZERO, node_id);
1066         if (disk) {
1067                 if (!init_part_stats(&disk->part0)) {
1068                         kfree(disk);
1069                         return NULL;
1070                 }
1071                 if (disk_expand_part_tbl(disk, 0)) {
1072                         free_part_stats(&disk->part0);
1073                         kfree(disk);
1074                         return NULL;
1075                 }
1076                 disk->part_tbl->part[0] = &disk->part0;
1077
1078                 disk->minors = minors;
1079                 rand_initialize_disk(disk);
1080                 disk_to_dev(disk)->class = &block_class;
1081                 disk_to_dev(disk)->type = &disk_type;
1082                 device_initialize(disk_to_dev(disk));
1083                 INIT_WORK(&disk->async_notify,
1084                         media_change_notify_thread);
1085                 disk->node_id = node_id;
1086         }
1087         return disk;
1088 }
1089 EXPORT_SYMBOL(alloc_disk_node);
1090
1091 struct kobject *get_disk(struct gendisk *disk)
1092 {
1093         struct module *owner;
1094         struct kobject *kobj;
1095
1096         if (!disk->fops)
1097                 return NULL;
1098         owner = disk->fops->owner;
1099         if (owner && !try_module_get(owner))
1100                 return NULL;
1101         kobj = kobject_get(&disk_to_dev(disk)->kobj);
1102         if (kobj == NULL) {
1103                 module_put(owner);
1104                 return NULL;
1105         }
1106         return kobj;
1107
1108 }
1109
1110 EXPORT_SYMBOL(get_disk);
1111
1112 void put_disk(struct gendisk *disk)
1113 {
1114         if (disk)
1115                 kobject_put(&disk_to_dev(disk)->kobj);
1116 }
1117
1118 EXPORT_SYMBOL(put_disk);
1119
1120 void set_device_ro(struct block_device *bdev, int flag)
1121 {
1122         bdev->bd_part->policy = flag;
1123 }
1124
1125 EXPORT_SYMBOL(set_device_ro);
1126
1127 void set_disk_ro(struct gendisk *disk, int flag)
1128 {
1129         struct disk_part_iter piter;
1130         struct hd_struct *part;
1131
1132         disk_part_iter_init(&piter, disk,
1133                             DISK_PITER_INCL_EMPTY | DISK_PITER_INCL_PART0);
1134         while ((part = disk_part_iter_next(&piter)))
1135                 part->policy = flag;
1136         disk_part_iter_exit(&piter);
1137 }
1138
1139 EXPORT_SYMBOL(set_disk_ro);
1140
1141 int bdev_read_only(struct block_device *bdev)
1142 {
1143         if (!bdev)
1144                 return 0;
1145         return bdev->bd_part->policy;
1146 }
1147
1148 EXPORT_SYMBOL(bdev_read_only);
1149
1150 int invalidate_partition(struct gendisk *disk, int partno)
1151 {
1152         int res = 0;
1153         struct block_device *bdev = bdget_disk(disk, partno);
1154         if (bdev) {
1155                 fsync_bdev(bdev);
1156                 res = __invalidate_device(bdev);
1157                 bdput(bdev);
1158         }
1159         return res;
1160 }
1161
1162 EXPORT_SYMBOL(invalidate_partition);