root/block/genhd.c

/* [previous][next][first][last][top][bottom][index][help] [+1 block/genhd.c] */

DEFINITIONS

This source file includes following definitions.
  1. disk_get_part
  2. disk_part_iter_init
  3. disk_part_iter_next
  4. disk_part_iter_exit
  5. sector_in_part
  6. disk_map_sector_rcu
  7. major_to_index
  8. blkdev_show
  9. register_blkdev
  10. unregister_blkdev
  11. blk_mangle_minor
  12. blk_alloc_devt
  13. blk_free_devt
  14. bdevt_str
  15. blk_register_region
  16. blk_unregister_region
  17. exact_match
  18. exact_lock
  19. register_disk
  20. add_disk
  21. del_gendisk
  22. get_gendisk
  23. bdget_disk
  24. printk_all_partitions
  25. disk_seqf_start
  26. disk_seqf_next
  27. disk_seqf_stop
  28. show_partition_start
  29. show_partition
  30. partitions_open
  31. base_probe
  32. genhd_device_init
  33. disk_range_show
  34. disk_ext_range_show
  35. disk_removable_show
  36. disk_ro_show
  37. disk_capability_show
  38. disk_alignment_offset_show
  39. disk_discard_alignment_show
  40. disk_replace_part_tbl
  41. disk_expand_part_tbl
  42. disk_release
  43. block_devnode
  44. diskstats_show
  45. diskstats_open
  46. proc_genhd_init
  47. blk_lookup_devt
  48. alloc_disk
  49. alloc_disk_node
  50. get_disk
  51. put_disk
  52. set_disk_ro_uevent
  53. set_device_ro
  54. set_disk_ro
  55. bdev_read_only
  56. invalidate_partition
  57. disk_events_poll_jiffies
  58. disk_block_events
  59. __disk_unblock_events
  60. disk_unblock_events
  61. disk_flush_events
  62. disk_clear_events
  63. disk_events_workfn
  64. disk_check_events
  65. __disk_events_show
  66. disk_events_show
  67. disk_events_async_show
  68. disk_events_poll_msecs_show
  69. disk_events_poll_msecs_store
  70. disk_events_set_dfl_poll_msecs
  71. disk_alloc_events
  72. disk_add_events
  73. disk_del_events
  74. disk_release_events

   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/backing-dev.h>
  12 #include <linux/init.h>
  13 #include <linux/spinlock.h>
  14 #include <linux/proc_fs.h>
  15 #include <linux/seq_file.h>
  16 #include <linux/slab.h>
  17 #include <linux/kmod.h>
  18 #include <linux/kobj_map.h>
  19 #include <linux/mutex.h>
  20 #include <linux/idr.h>
  21 #include <linux/log2.h>
  22 #include <linux/pm_runtime.h>
  23 
  24 #include "blk.h"
  25 
  26 static DEFINE_MUTEX(block_class_lock);
  27 struct kobject *block_depr;
  28 
  29 /* for extended dynamic devt allocation, currently only one major is used */
  30 #define NR_EXT_DEVT             (1 << MINORBITS)
  31 
  32 /* For extended devt allocation.  ext_devt_lock prevents look up
  33  * results from going away underneath its user.
  34  */
  35 static DEFINE_SPINLOCK(ext_devt_lock);
  36 static DEFINE_IDR(ext_devt_idr);
  37 
  38 static struct device_type disk_type;
  39 
  40 static void disk_check_events(struct disk_events *ev,
  41                               unsigned int *clearing_ptr);
  42 static void disk_alloc_events(struct gendisk *disk);
  43 static void disk_add_events(struct gendisk *disk);
  44 static void disk_del_events(struct gendisk *disk);
  45 static void disk_release_events(struct gendisk *disk);
  46 
  47 /**
  48  * disk_get_part - get partition
  49  * @disk: disk to look partition from
  50  * @partno: partition number
  51  *
  52  * Look for partition @partno from @disk.  If found, increment
  53  * reference count and return it.
  54  *
  55  * CONTEXT:
  56  * Don't care.
  57  *
  58  * RETURNS:
  59  * Pointer to the found partition on success, NULL if not found.
  60  */
  61 struct hd_struct *disk_get_part(struct gendisk *disk, int partno)
     /* [previous][next][first][last][top][bottom][index][help] [+61 block/genhd.c] */
  62 {
  63         struct hd_struct *part = NULL;
  64         struct disk_part_tbl *ptbl;
  65 
  66         if (unlikely(partno < 0))
  67                 return NULL;
  68 
  69         rcu_read_lock();
  70 
  71         ptbl = rcu_dereference(disk->part_tbl);
  72         if (likely(partno < ptbl->len)) {
  73                 part = rcu_dereference(ptbl->part[partno]);
  74                 if (part)
  75                         get_device(part_to_dev(part));
  76         }
  77 
  78         rcu_read_unlock();
  79 
  80         return part;
  81 }
  82 EXPORT_SYMBOL_GPL(disk_get_part);
  83 
  84 /**
  85  * disk_part_iter_init - initialize partition iterator
  86  * @piter: iterator to initialize
  87  * @disk: disk to iterate over
  88  * @flags: DISK_PITER_* flags
  89  *
  90  * Initialize @piter so that it iterates over partitions of @disk.
  91  *
  92  * CONTEXT:
  93  * Don't care.
  94  */
  95 void disk_part_iter_init(struct disk_part_iter *piter, struct gendisk *disk,
     /* [previous][next][first][last][top][bottom][index][help] [+95 block/genhd.c] */
  96                           unsigned int flags)
  97 {
  98         struct disk_part_tbl *ptbl;
  99 
 100         rcu_read_lock();
 101         ptbl = rcu_dereference(disk->part_tbl);
 102 
 103         piter->disk = disk;
 104         piter->part = NULL;
 105 
 106         if (flags & DISK_PITER_REVERSE)
 107                 piter->idx = ptbl->len - 1;
 108         else if (flags & (DISK_PITER_INCL_PART0 | DISK_PITER_INCL_EMPTY_PART0))
 109                 piter->idx = 0;
 110         else
 111                 piter->idx = 1;
 112 
 113         piter->flags = flags;
 114 
 115         rcu_read_unlock();
 116 }
 117 EXPORT_SYMBOL_GPL(disk_part_iter_init);
 118 
 119 /**
 120  * disk_part_iter_next - proceed iterator to the next partition and return it
 121  * @piter: iterator of interest
 122  *
 123  * Proceed @piter to the next partition and return it.
 124  *
 125  * CONTEXT:
 126  * Don't care.
 127  */
 128 struct hd_struct *disk_part_iter_next(struct disk_part_iter *piter)
     /* [previous][next][first][last][top][bottom][index][help] [+128 block/genhd.c] */
 129 {
 130         struct disk_part_tbl *ptbl;
 131         int inc, end;
 132 
 133         /* put the last partition */
 134         disk_put_part(piter->part);
 135         piter->part = NULL;
 136 
 137         /* get part_tbl */
 138         rcu_read_lock();
 139         ptbl = rcu_dereference(piter->disk->part_tbl);
 140 
 141         /* determine iteration parameters */
 142         if (piter->flags & DISK_PITER_REVERSE) {
 143                 inc = -1;
 144                 if (piter->flags & (DISK_PITER_INCL_PART0 |
 145                                     DISK_PITER_INCL_EMPTY_PART0))
 146                         end = -1;
 147                 else
 148                         end = 0;
 149         } else {
 150                 inc = 1;
 151                 end = ptbl->len;
 152         }
 153 
 154         /* iterate to the next partition */
 155         for (; piter->idx != end; piter->idx += inc) {
 156                 struct hd_struct *part;
 157 
 158                 part = rcu_dereference(ptbl->part[piter->idx]);
 159                 if (!part)
 160                         continue;
 161                 if (!part_nr_sects_read(part) &&
 162                     !(piter->flags & DISK_PITER_INCL_EMPTY) &&
 163                     !(piter->flags & DISK_PITER_INCL_EMPTY_PART0 &&
 164                       piter->idx == 0))
 165                         continue;
 166 
 167                 get_device(part_to_dev(part));
 168                 piter->part = part;
 169                 piter->idx += inc;
 170                 break;
 171         }
 172 
 173         rcu_read_unlock();
 174 
 175         return piter->part;
 176 }
 177 EXPORT_SYMBOL_GPL(disk_part_iter_next);
 178 
 179 /**
 180  * disk_part_iter_exit - finish up partition iteration
 181  * @piter: iter of interest
 182  *
 183  * Called when iteration is over.  Cleans up @piter.
 184  *
 185  * CONTEXT:
 186  * Don't care.
 187  */
 188 void disk_part_iter_exit(struct disk_part_iter *piter)
     /* [previous][next][first][last][top][bottom][index][help] [+188 block/genhd.c] */
 189 {
 190         disk_put_part(piter->part);
 191         piter->part = NULL;
 192 }
 193 EXPORT_SYMBOL_GPL(disk_part_iter_exit);
 194 
 195 static inline int sector_in_part(struct hd_struct *part, sector_t sector)
     /* [previous][next][first][last][top][bottom][index][help] [+195 block/genhd.c] */
 196 {
 197         return part->start_sect <= sector &&
 198                 sector < part->start_sect + part_nr_sects_read(part);
 199 }
 200 
 201 /**
 202  * disk_map_sector_rcu - map sector to partition
 203  * @disk: gendisk of interest
 204  * @sector: sector to map
 205  *
 206  * Find out which partition @sector maps to on @disk.  This is
 207  * primarily used for stats accounting.
 208  *
 209  * CONTEXT:
 210  * RCU read locked.  The returned partition pointer is valid only
 211  * while preemption is disabled.
 212  *
 213  * RETURNS:
 214  * Found partition on success, part0 is returned if no partition matches
 215  */
 216 struct hd_struct *disk_map_sector_rcu(struct gendisk *disk, sector_t sector)
     /* [previous][next][first][last][top][bottom][index][help] [+216 block/genhd.c] */
 217 {
 218         struct disk_part_tbl *ptbl;
 219         struct hd_struct *part;
 220         int i;
 221 
 222         ptbl = rcu_dereference(disk->part_tbl);
 223 
 224         part = rcu_dereference(ptbl->last_lookup);
 225         if (part && sector_in_part(part, sector))
 226                 return part;
 227 
 228         for (i = 1; i < ptbl->len; i++) {
 229                 part = rcu_dereference(ptbl->part[i]);
 230 
 231                 if (part && sector_in_part(part, sector)) {
 232                         rcu_assign_pointer(ptbl->last_lookup, part);
 233                         return part;
 234                 }
 235         }
 236         return &disk->part0;
 237 }
 238 EXPORT_SYMBOL_GPL(disk_map_sector_rcu);
 239 
 240 /*
 241  * Can be deleted altogether. Later.
 242  *
 243  */
 244 static struct blk_major_name {
 245         struct blk_major_name *next;
 246         int major;
 247         char name[16];
 248 } *major_names[BLKDEV_MAJOR_HASH_SIZE];
 249 
 250 /* index in the above - for now: assume no multimajor ranges */
 251 static inline int major_to_index(unsigned major)
     /* [previous][next][first][last][top][bottom][index][help] [+251 block/genhd.c] */
 252 {
 253         return major % BLKDEV_MAJOR_HASH_SIZE;
 254 }
 255 
 256 #ifdef CONFIG_PROC_FS
 257 void blkdev_show(struct seq_file *seqf, off_t offset)
     /* [previous][next][first][last][top][bottom][index][help] [+257 block/genhd.c] */
 258 {
 259         struct blk_major_name *dp;
 260 
 261         if (offset < BLKDEV_MAJOR_HASH_SIZE) {
 262                 mutex_lock(&block_class_lock);
 263                 for (dp = major_names[offset]; dp; dp = dp->next)
 264                         seq_printf(seqf, "%3d %s\n", dp->major, dp->name);
 265                 mutex_unlock(&block_class_lock);
 266         }
 267 }
 268 #endif /* CONFIG_PROC_FS */
 269 
 270 /**
 271  * register_blkdev - register a new block device
 272  *
 273  * @major: the requested major device number [1..255]. If @major=0, try to
 274  *         allocate any unused major number.
 275  * @name: the name of the new block device as a zero terminated string
 276  *
 277  * The @name must be unique within the system.
 278  *
 279  * The return value depends on the @major input parameter.
 280  *  - if a major device number was requested in range [1..255] then the
 281  *    function returns zero on success, or a negative error code
 282  *  - if any unused major number was requested with @major=0 parameter
 283  *    then the return value is the allocated major number in range
 284  *    [1..255] or a negative error code otherwise
 285  */
 286 int register_blkdev(unsigned int major, const char *name)
     /* [previous][next][first][last][top][bottom][index][help] [+286 block/genhd.c] */
 287 {
 288         struct blk_major_name **n, *p;
 289         int index, ret = 0;
 290 
 291         mutex_lock(&block_class_lock);
 292 
 293         /* temporary */
 294         if (major == 0) {
 295                 for (index = ARRAY_SIZE(major_names)-1; index > 0; index--) {
 296                         if (major_names[index] == NULL)
 297                                 break;
 298                 }
 299 
 300                 if (index == 0) {
 301                         printk("register_blkdev: failed to get major for %s\n",
 302                                name);
 303                         ret = -EBUSY;
 304                         goto out;
 305                 }
 306                 major = index;
 307                 ret = major;
 308         }
 309 
 310         p = kmalloc(sizeof(struct blk_major_name), GFP_KERNEL);
 311         if (p == NULL) {
 312                 ret = -ENOMEM;
 313                 goto out;
 314         }
 315 
 316         p->major = major;
 317         strlcpy(p->name, name, sizeof(p->name));
 318         p->next = NULL;
 319         index = major_to_index(major);
 320 
 321         for (n = &major_names[index]; *n; n = &(*n)->next) {
 322                 if ((*n)->major == major)
 323                         break;
 324         }
 325         if (!*n)
 326                 *n = p;
 327         else
 328                 ret = -EBUSY;
 329 
 330         if (ret < 0) {
 331                 printk("register_blkdev: cannot get major %d for %s\n",
 332                        major, name);
 333                 kfree(p);
 334         }
 335 out:
 336         mutex_unlock(&block_class_lock);
 337         return ret;
 338 }
 339 
 340 EXPORT_SYMBOL(register_blkdev);
 341 
 342 void unregister_blkdev(unsigned int major, const char *name)
     /* [previous][next][first][last][top][bottom][index][help] [+342 block/genhd.c] */
 343 {
 344         struct blk_major_name **n;
 345         struct blk_major_name *p = NULL;
 346         int index = major_to_index(major);
 347 
 348         mutex_lock(&block_class_lock);
 349         for (n = &major_names[index]; *n; n = &(*n)->next)
 350                 if ((*n)->major == major)
 351                         break;
 352         if (!*n || strcmp((*n)->name, name)) {
 353                 WARN_ON(1);
 354         } else {
 355                 p = *n;
 356                 *n = p->next;
 357         }
 358         mutex_unlock(&block_class_lock);
 359         kfree(p);
 360 }
 361 
 362 EXPORT_SYMBOL(unregister_blkdev);
 363 
 364 static struct kobj_map *bdev_map;
 365 
 366 /**
 367  * blk_mangle_minor - scatter minor numbers apart
 368  * @minor: minor number to mangle
 369  *
 370  * Scatter consecutively allocated @minor number apart if MANGLE_DEVT
 371  * is enabled.  Mangling twice gives the original value.
 372  *
 373  * RETURNS:
 374  * Mangled value.
 375  *
 376  * CONTEXT:
 377  * Don't care.
 378  */
 379 static int blk_mangle_minor(int minor)
     /* [previous][next][first][last][top][bottom][index][help] [+379 block/genhd.c] */
 380 {
 381 #ifdef CONFIG_DEBUG_BLOCK_EXT_DEVT
 382         int i;
 383 
 384         for (i = 0; i < MINORBITS / 2; i++) {
 385                 int low = minor & (1 << i);
 386                 int high = minor & (1 << (MINORBITS - 1 - i));
 387                 int distance = MINORBITS - 1 - 2 * i;
 388 
 389                 minor ^= low | high;    /* clear both bits */
 390                 low <<= distance;       /* swap the positions */
 391                 high >>= distance;
 392                 minor |= low | high;    /* and set */
 393         }
 394 #endif
 395         return minor;
 396 }
 397 
 398 /**
 399  * blk_alloc_devt - allocate a dev_t for a partition
 400  * @part: partition to allocate dev_t for
 401  * @devt: out parameter for resulting dev_t
 402  *
 403  * Allocate a dev_t for block device.
 404  *
 405  * RETURNS:
 406  * 0 on success, allocated dev_t is returned in *@devt.  -errno on
 407  * failure.
 408  *
 409  * CONTEXT:
 410  * Might sleep.
 411  */
 412 int blk_alloc_devt(struct hd_struct *part, dev_t *devt)
     /* [previous][next][first][last][top][bottom][index][help] [+412 block/genhd.c] */
 413 {
 414         struct gendisk *disk = part_to_disk(part);
 415         int idx;
 416 
 417         /* in consecutive minor range? */
 418         if (part->partno < disk->minors) {
 419                 *devt = MKDEV(disk->major, disk->first_minor + part->partno);
 420                 return 0;
 421         }
 422 
 423         /* allocate ext devt */
 424         idr_preload(GFP_KERNEL);
 425 
 426         spin_lock_bh(&ext_devt_lock);
 427         idx = idr_alloc(&ext_devt_idr, part, 0, NR_EXT_DEVT, GFP_NOWAIT);
 428         spin_unlock_bh(&ext_devt_lock);
 429 
 430         idr_preload_end();
 431         if (idx < 0)
 432                 return idx == -ENOSPC ? -EBUSY : idx;
 433 
 434         *devt = MKDEV(BLOCK_EXT_MAJOR, blk_mangle_minor(idx));
 435         return 0;
 436 }
 437 
 438 /**
 439  * blk_free_devt - free a dev_t
 440  * @devt: dev_t to free
 441  *
 442  * Free @devt which was allocated using blk_alloc_devt().
 443  *
 444  * CONTEXT:
 445  * Might sleep.
 446  */
 447 void blk_free_devt(dev_t devt)
     /* [previous][next][first][last][top][bottom][index][help] [+447 block/genhd.c] */
 448 {
 449         if (devt == MKDEV(0, 0))
 450                 return;
 451 
 452         if (MAJOR(devt) == BLOCK_EXT_MAJOR) {
 453                 spin_lock_bh(&ext_devt_lock);
 454                 idr_remove(&ext_devt_idr, blk_mangle_minor(MINOR(devt)));
 455                 spin_unlock_bh(&ext_devt_lock);
 456         }
 457 }
 458 
 459 static char *bdevt_str(dev_t devt, char *buf)
     /* [previous][next][first][last][top][bottom][index][help] [+459 block/genhd.c] */
 460 {
 461         if (MAJOR(devt) <= 0xff && MINOR(devt) <= 0xff) {
 462                 char tbuf[BDEVT_SIZE];
 463                 snprintf(tbuf, BDEVT_SIZE, "%02x%02x", MAJOR(devt), MINOR(devt));
 464                 snprintf(buf, BDEVT_SIZE, "%-9s", tbuf);
 465         } else
 466                 snprintf(buf, BDEVT_SIZE, "%03x:%05x", MAJOR(devt), MINOR(devt));
 467 
 468         return buf;
 469 }
 470 
 471 /*
 472  * Register device numbers dev..(dev+range-1)
 473  * range must be nonzero
 474  * The hash chain is sorted on range, so that subranges can override.
 475  */
 476 void blk_register_region(dev_t devt, unsigned long range, struct module *module,
     /* [previous][next][first][last][top][bottom][index][help] [+476 block/genhd.c] */
 477                          struct kobject *(*probe)(dev_t, int *, void *),
 478                          int (*lock)(dev_t, void *), void *data)
 479 {
 480         kobj_map(bdev_map, devt, range, module, probe, lock, data);
 481 }
 482 
 483 EXPORT_SYMBOL(blk_register_region);
 484 
 485 void blk_unregister_region(dev_t devt, unsigned long range)
     /* [previous][next][first][last][top][bottom][index][help] [+485 block/genhd.c] */
 486 {
 487         kobj_unmap(bdev_map, devt, range);
 488 }
 489 
 490 EXPORT_SYMBOL(blk_unregister_region);
 491 
 492 static struct kobject *exact_match(dev_t devt, int *partno, void *data)
     /* [previous][next][first][last][top][bottom][index][help] [+492 block/genhd.c] */
 493 {
 494         struct gendisk *p = data;
 495 
 496         return &disk_to_dev(p)->kobj;
 497 }
 498 
 499 static int exact_lock(dev_t devt, void *data)
     /* [previous][next][first][last][top][bottom][index][help] [+499 block/genhd.c] */
 500 {
 501         struct gendisk *p = data;
 502 
 503         if (!get_disk(p))
 504                 return -1;
 505         return 0;
 506 }
 507 
 508 static void register_disk(struct gendisk *disk)
     /* [previous][next][first][last][top][bottom][index][help] [+508 block/genhd.c] */
 509 {
 510         struct device *ddev = disk_to_dev(disk);
 511         struct block_device *bdev;
 512         struct disk_part_iter piter;
 513         struct hd_struct *part;
 514         int err;
 515 
 516         ddev->parent = disk->driverfs_dev;
 517 
 518         dev_set_name(ddev, "%s", disk->disk_name);
 519 
 520         /* delay uevents, until we scanned partition table */
 521         dev_set_uevent_suppress(ddev, 1);
 522 
 523         if (device_add(ddev))
 524                 return;
 525         if (!sysfs_deprecated) {
 526                 err = sysfs_create_link(block_depr, &ddev->kobj,
 527                                         kobject_name(&ddev->kobj));
 528                 if (err) {
 529                         device_del(ddev);
 530                         return;
 531                 }
 532         }
 533 
 534         /*
 535          * avoid probable deadlock caused by allocating memory with
 536          * GFP_KERNEL in runtime_resume callback of its all ancestor
 537          * devices
 538          */
 539         pm_runtime_set_memalloc_noio(ddev, true);
 540 
 541         disk->part0.holder_dir = kobject_create_and_add("holders", &ddev->kobj);
 542         disk->slave_dir = kobject_create_and_add("slaves", &ddev->kobj);
 543 
 544         /* No minors to use for partitions */
 545         if (!disk_part_scan_enabled(disk))
 546                 goto exit;
 547 
 548         /* No such device (e.g., media were just removed) */
 549         if (!get_capacity(disk))
 550                 goto exit;
 551 
 552         bdev = bdget_disk(disk, 0);
 553         if (!bdev)
 554                 goto exit;
 555 
 556         bdev->bd_invalidated = 1;
 557         err = blkdev_get(bdev, FMODE_READ, NULL);
 558         if (err < 0)
 559                 goto exit;
 560         blkdev_put(bdev, FMODE_READ);
 561 
 562 exit:
 563         /* announce disk after possible partitions are created */
 564         dev_set_uevent_suppress(ddev, 0);
 565         kobject_uevent(&ddev->kobj, KOBJ_ADD);
 566 
 567         /* announce possible partitions */
 568         disk_part_iter_init(&piter, disk, 0);
 569         while ((part = disk_part_iter_next(&piter)))
 570                 kobject_uevent(&part_to_dev(part)->kobj, KOBJ_ADD);
 571         disk_part_iter_exit(&piter);
 572 }
 573 
 574 /**
 575  * add_disk - add partitioning information to kernel list
 576  * @disk: per-device partitioning information
 577  *
 578  * This function registers the partitioning information in @disk
 579  * with the kernel.
 580  *
 581  * FIXME: error handling
 582  */
 583 void add_disk(struct gendisk *disk)
     /* [previous][next][first][last][top][bottom][index][help] [+583 block/genhd.c] */
 584 {
 585         struct backing_dev_info *bdi;
 586         dev_t devt;
 587         int retval;
 588 
 589         /* minors == 0 indicates to use ext devt from part0 and should
 590          * be accompanied with EXT_DEVT flag.  Make sure all
 591          * parameters make sense.
 592          */
 593         WARN_ON(disk->minors && !(disk->major || disk->first_minor));
 594         WARN_ON(!disk->minors && !(disk->flags & GENHD_FL_EXT_DEVT));
 595 
 596         disk->flags |= GENHD_FL_UP;
 597 
 598         retval = blk_alloc_devt(&disk->part0, &devt);
 599         if (retval) {
 600                 WARN_ON(1);
 601                 return;
 602         }
 603         disk_to_dev(disk)->devt = devt;
 604 
 605         /* ->major and ->first_minor aren't supposed to be
 606          * dereferenced from here on, but set them just in case.
 607          */
 608         disk->major = MAJOR(devt);
 609         disk->first_minor = MINOR(devt);
 610 
 611         disk_alloc_events(disk);
 612 
 613         /* Register BDI before referencing it from bdev */
 614         bdi = &disk->queue->backing_dev_info;
 615         bdi_register_dev(bdi, disk_devt(disk));
 616 
 617         blk_register_region(disk_devt(disk), disk->minors, NULL,
 618                             exact_match, exact_lock, disk);
 619         register_disk(disk);
 620         blk_register_queue(disk);
 621 
 622         /*
 623          * Take an extra ref on queue which will be put on disk_release()
 624          * so that it sticks around as long as @disk is there.
 625          */
 626         WARN_ON_ONCE(!blk_get_queue(disk->queue));
 627 
 628         retval = sysfs_create_link(&disk_to_dev(disk)->kobj, &bdi->dev->kobj,
 629                                    "bdi");
 630         WARN_ON(retval);
 631 
 632         disk_add_events(disk);
 633         blk_integrity_add(disk);
 634 }
 635 EXPORT_SYMBOL(add_disk);
 636 
 637 void del_gendisk(struct gendisk *disk)
     /* [previous][next][first][last][top][bottom][index][help] [+637 block/genhd.c] */
 638 {
 639         struct disk_part_iter piter;
 640         struct hd_struct *part;
 641 
 642         blk_integrity_del(disk);
 643         disk_del_events(disk);
 644 
 645         /* invalidate stuff */
 646         disk_part_iter_init(&piter, disk,
 647                              DISK_PITER_INCL_EMPTY | DISK_PITER_REVERSE);
 648         while ((part = disk_part_iter_next(&piter))) {
 649                 invalidate_partition(disk, part->partno);
 650                 delete_partition(disk, part->partno);
 651         }
 652         disk_part_iter_exit(&piter);
 653 
 654         invalidate_partition(disk, 0);
 655         set_capacity(disk, 0);
 656         disk->flags &= ~GENHD_FL_UP;
 657 
 658         sysfs_remove_link(&disk_to_dev(disk)->kobj, "bdi");
 659         blk_unregister_queue(disk);
 660         blk_unregister_region(disk_devt(disk), disk->minors);
 661 
 662         part_stat_set_all(&disk->part0, 0);
 663         disk->part0.stamp = 0;
 664 
 665         kobject_put(disk->part0.holder_dir);
 666         kobject_put(disk->slave_dir);
 667         disk->driverfs_dev = NULL;
 668         if (!sysfs_deprecated)
 669                 sysfs_remove_link(block_depr, dev_name(disk_to_dev(disk)));
 670         pm_runtime_set_memalloc_noio(disk_to_dev(disk), false);
 671         device_del(disk_to_dev(disk));
 672 }
 673 EXPORT_SYMBOL(del_gendisk);
 674 
 675 /**
 676  * get_gendisk - get partitioning information for a given device
 677  * @devt: device to get partitioning information for
 678  * @partno: returned partition index
 679  *
 680  * This function gets the structure containing partitioning
 681  * information for the given device @devt.
 682  */
 683 struct gendisk *get_gendisk(dev_t devt, int *partno)
     /* [previous][next][first][last][top][bottom][index][help] [+683 block/genhd.c] */
 684 {
 685         struct gendisk *disk = NULL;
 686 
 687         if (MAJOR(devt) != BLOCK_EXT_MAJOR) {
 688                 struct kobject *kobj;
 689 
 690                 kobj = kobj_lookup(bdev_map, devt, partno);
 691                 if (kobj)
 692                         disk = dev_to_disk(kobj_to_dev(kobj));
 693         } else {
 694                 struct hd_struct *part;
 695 
 696                 spin_lock_bh(&ext_devt_lock);
 697                 part = idr_find(&ext_devt_idr, blk_mangle_minor(MINOR(devt)));
 698                 if (part && get_disk(part_to_disk(part))) {
 699                         *partno = part->partno;
 700                         disk = part_to_disk(part);
 701                 }
 702                 spin_unlock_bh(&ext_devt_lock);
 703         }
 704 
 705         return disk;
 706 }
 707 EXPORT_SYMBOL(get_gendisk);
 708 
 709 /**
 710  * bdget_disk - do bdget() by gendisk and partition number
 711  * @disk: gendisk of interest
 712  * @partno: partition number
 713  *
 714  * Find partition @partno from @disk, do bdget() on it.
 715  *
 716  * CONTEXT:
 717  * Don't care.
 718  *
 719  * RETURNS:
 720  * Resulting block_device on success, NULL on failure.
 721  */
 722 struct block_device *bdget_disk(struct gendisk *disk, int partno)
     /* [previous][next][first][last][top][bottom][index][help] [+722 block/genhd.c] */
 723 {
 724         struct hd_struct *part;
 725         struct block_device *bdev = NULL;
 726 
 727         part = disk_get_part(disk, partno);
 728         if (part)
 729                 bdev = bdget(part_devt(part));
 730         disk_put_part(part);
 731 
 732         return bdev;
 733 }
 734 EXPORT_SYMBOL(bdget_disk);
 735 
 736 /*
 737  * print a full list of all partitions - intended for places where the root
 738  * filesystem can't be mounted and thus to give the victim some idea of what
 739  * went wrong
 740  */
 741 void __init printk_all_partitions(void)
     /* [previous][next][first][last][top][bottom][index][help] [+741 block/genhd.c] */
 742 {
 743         struct class_dev_iter iter;
 744         struct device *dev;
 745 
 746         class_dev_iter_init(&iter, &block_class, NULL, &disk_type);
 747         while ((dev = class_dev_iter_next(&iter))) {
 748                 struct gendisk *disk = dev_to_disk(dev);
 749                 struct disk_part_iter piter;
 750                 struct hd_struct *part;
 751                 char name_buf[BDEVNAME_SIZE];
 752                 char devt_buf[BDEVT_SIZE];
 753 
 754                 /*
 755                  * Don't show empty devices or things that have been
 756                  * suppressed
 757                  */
 758                 if (get_capacity(disk) == 0 ||
 759                     (disk->flags & GENHD_FL_SUPPRESS_PARTITION_INFO))
 760                         continue;
 761 
 762                 /*
 763                  * Note, unlike /proc/partitions, I am showing the
 764                  * numbers in hex - the same format as the root=
 765                  * option takes.
 766                  */
 767                 disk_part_iter_init(&piter, disk, DISK_PITER_INCL_PART0);
 768                 while ((part = disk_part_iter_next(&piter))) {
 769                         bool is_part0 = part == &disk->part0;
 770 
 771                         printk("%s%s %10llu %s %s", is_part0 ? "" : "  ",
 772                                bdevt_str(part_devt(part), devt_buf),
 773                                (unsigned long long)part_nr_sects_read(part) >> 1
 774                                , disk_name(disk, part->partno, name_buf),
 775                                part->info ? part->info->uuid : "");
 776                         if (is_part0) {
 777                                 if (disk->driverfs_dev != NULL &&
 778                                     disk->driverfs_dev->driver != NULL)
 779                                         printk(" driver: %s\n",
 780                                               disk->driverfs_dev->driver->name);
 781                                 else
 782                                         printk(" (driver?)\n");
 783                         } else
 784                                 printk("\n");
 785                 }
 786                 disk_part_iter_exit(&piter);
 787         }
 788         class_dev_iter_exit(&iter);
 789 }
 790 
 791 #ifdef CONFIG_PROC_FS
 792 /* iterator */
 793 static void *disk_seqf_start(struct seq_file *seqf, loff_t *pos)
     /* [previous][next][first][last][top][bottom][index][help] [+793 block/genhd.c] */
 794 {
 795         loff_t skip = *pos;
 796         struct class_dev_iter *iter;
 797         struct device *dev;
 798 
 799         iter = kmalloc(sizeof(*iter), GFP_KERNEL);
 800         if (!iter)
 801                 return ERR_PTR(-ENOMEM);
 802 
 803         seqf->private = iter;
 804         class_dev_iter_init(iter, &block_class, NULL, &disk_type);
 805         do {
 806                 dev = class_dev_iter_next(iter);
 807                 if (!dev)
 808                         return NULL;
 809         } while (skip--);
 810 
 811         return dev_to_disk(dev);
 812 }
 813 
 814 static void *disk_seqf_next(struct seq_file *seqf, void *v, loff_t *pos)
     /* [previous][next][first][last][top][bottom][index][help] [+814 block/genhd.c] */
 815 {
 816         struct device *dev;
 817 
 818         (*pos)++;
 819         dev = class_dev_iter_next(seqf->private);
 820         if (dev)
 821                 return dev_to_disk(dev);
 822 
 823         return NULL;
 824 }
 825 
 826 static void disk_seqf_stop(struct seq_file *seqf, void *v)
     /* [previous][next][first][last][top][bottom][index][help] [+826 block/genhd.c] */
 827 {
 828         struct class_dev_iter *iter = seqf->private;
 829 
 830         /* stop is called even after start failed :-( */
 831         if (iter) {
 832                 class_dev_iter_exit(iter);
 833                 kfree(iter);
 834         }
 835 }
 836 
 837 static void *show_partition_start(struct seq_file *seqf, loff_t *pos)
     /* [previous][next][first][last][top][bottom][index][help] [+837 block/genhd.c] */
 838 {
 839         void *p;
 840 
 841         p = disk_seqf_start(seqf, pos);
 842         if (!IS_ERR_OR_NULL(p) && !*pos)
 843                 seq_puts(seqf, "major minor  #blocks  name\n\n");
 844         return p;
 845 }
 846 
 847 static int show_partition(struct seq_file *seqf, void *v)
     /* [previous][next][first][last][top][bottom][index][help] [+847 block/genhd.c] */
 848 {
 849         struct gendisk *sgp = v;
 850         struct disk_part_iter piter;
 851         struct hd_struct *part;
 852         char buf[BDEVNAME_SIZE];
 853 
 854         /* Don't show non-partitionable removeable devices or empty devices */
 855         if (!get_capacity(sgp) || (!disk_max_parts(sgp) &&
 856                                    (sgp->flags & GENHD_FL_REMOVABLE)))
 857                 return 0;
 858         if (sgp->flags & GENHD_FL_SUPPRESS_PARTITION_INFO)
 859                 return 0;
 860 
 861         /* show the full disk and all non-0 size partitions of it */
 862         disk_part_iter_init(&piter, sgp, DISK_PITER_INCL_PART0);
 863         while ((part = disk_part_iter_next(&piter)))
 864                 seq_printf(seqf, "%4d  %7d %10llu %s\n",
 865                            MAJOR(part_devt(part)), MINOR(part_devt(part)),
 866                            (unsigned long long)part_nr_sects_read(part) >> 1,
 867                            disk_name(sgp, part->partno, buf));
 868         disk_part_iter_exit(&piter);
 869 
 870         return 0;
 871 }
 872 
 873 static const struct seq_operations partitions_op = {
 874         .start  = show_partition_start,
 875         .next   = disk_seqf_next,
 876         .stop   = disk_seqf_stop,
 877         .show   = show_partition
 878 };
 879 
 880 static int partitions_open(struct inode *inode, struct file *file)
     /* [previous][next][first][last][top][bottom][index][help] [+880 block/genhd.c] */
 881 {
 882         return seq_open(file, &partitions_op);
 883 }
 884 
 885 static const struct file_operations proc_partitions_operations = {
 886         .open           = partitions_open,
 887         .read           = seq_read,
 888         .llseek         = seq_lseek,
 889         .release        = seq_release,
 890 };
 891 #endif
 892 
 893 
 894 static struct kobject *base_probe(dev_t devt, int *partno, void *data)
     /* [previous][next][first][last][top][bottom][index][help] [+894 block/genhd.c] */
 895 {
 896         if (request_module("block-major-%d-%d", MAJOR(devt), MINOR(devt)) > 0)
 897                 /* Make old-style 2.4 aliases work */
 898                 request_module("block-major-%d", MAJOR(devt));
 899         return NULL;
 900 }
 901 
 902 static int __init genhd_device_init(void)
     /* [previous][next][first][last][top][bottom][index][help] [+902 block/genhd.c] */
 903 {
 904         int error;
 905 
 906         block_class.dev_kobj = sysfs_dev_block_kobj;
 907         error = class_register(&block_class);
 908         if (unlikely(error))
 909                 return error;
 910         bdev_map = kobj_map_init(base_probe, &block_class_lock);
 911         blk_dev_init();
 912 
 913         register_blkdev(BLOCK_EXT_MAJOR, "blkext");
 914 
 915         /* create top-level block dir */
 916         if (!sysfs_deprecated)
 917                 block_depr = kobject_create_and_add("block", NULL);
 918         return 0;
 919 }
 920 
 921 subsys_initcall(genhd_device_init);
 922 
 923 static ssize_t disk_range_show(struct device *dev,
     /* [previous][next][first][last][top][bottom][index][help] [+923 block/genhd.c] */
 924                                struct device_attribute *attr, char *buf)
 925 {
 926         struct gendisk *disk = dev_to_disk(dev);
 927 
 928         return sprintf(buf, "%d\n", disk->minors);
 929 }
 930 
 931 static ssize_t disk_ext_range_show(struct device *dev,
     /* [previous][next][first][last][top][bottom][index][help] [+931 block/genhd.c] */
 932                                    struct device_attribute *attr, char *buf)
 933 {
 934         struct gendisk *disk = dev_to_disk(dev);
 935 
 936         return sprintf(buf, "%d\n", disk_max_parts(disk));
 937 }
 938 
 939 static ssize_t disk_removable_show(struct device *dev,
     /* [previous][next][first][last][top][bottom][index][help] [+939 block/genhd.c] */
 940                                    struct device_attribute *attr, char *buf)
 941 {
 942         struct gendisk *disk = dev_to_disk(dev);
 943 
 944         return sprintf(buf, "%d\n",
 945                        (disk->flags & GENHD_FL_REMOVABLE ? 1 : 0));
 946 }
 947 
 948 static ssize_t disk_ro_show(struct device *dev,
     /* [previous][next][first][last][top][bottom][index][help] [+948 block/genhd.c] */
 949                                    struct device_attribute *attr, char *buf)
 950 {
 951         struct gendisk *disk = dev_to_disk(dev);
 952 
 953         return sprintf(buf, "%d\n", get_disk_ro(disk) ? 1 : 0);
 954 }
 955 
 956 static ssize_t disk_capability_show(struct device *dev,
     /* [previous][next][first][last][top][bottom][index][help] [+956 block/genhd.c] */
 957                                     struct device_attribute *attr, char *buf)
 958 {
 959         struct gendisk *disk = dev_to_disk(dev);
 960 
 961         return sprintf(buf, "%x\n", disk->flags);
 962 }
 963 
 964 static ssize_t disk_alignment_offset_show(struct device *dev,
     /* [previous][next][first][last][top][bottom][index][help] [+964 block/genhd.c] */
 965                                           struct device_attribute *attr,
 966                                           char *buf)
 967 {
 968         struct gendisk *disk = dev_to_disk(dev);
 969 
 970         return sprintf(buf, "%d\n", queue_alignment_offset(disk->queue));
 971 }
 972 
 973 static ssize_t disk_discard_alignment_show(struct device *dev,
     /* [previous][next][first][last][top][bottom][index][help] [+973 block/genhd.c] */
 974                                            struct device_attribute *attr,
 975                                            char *buf)
 976 {
 977         struct gendisk *disk = dev_to_disk(dev);
 978 
 979         return sprintf(buf, "%d\n", queue_discard_alignment(disk->queue));
 980 }
 981 
 982 static DEVICE_ATTR(range, S_IRUGO, disk_range_show, NULL);
 983 static DEVICE_ATTR(ext_range, S_IRUGO, disk_ext_range_show, NULL);
 984 static DEVICE_ATTR(removable, S_IRUGO, disk_removable_show, NULL);
 985 static DEVICE_ATTR(ro, S_IRUGO, disk_ro_show, NULL);
 986 static DEVICE_ATTR(size, S_IRUGO, part_size_show, NULL);
 987 static DEVICE_ATTR(alignment_offset, S_IRUGO, disk_alignment_offset_show, NULL);
 988 static DEVICE_ATTR(discard_alignment, S_IRUGO, disk_discard_alignment_show,
 989                    NULL);
 990 static DEVICE_ATTR(capability, S_IRUGO, disk_capability_show, NULL);
 991 static DEVICE_ATTR(stat, S_IRUGO, part_stat_show, NULL);
 992 static DEVICE_ATTR(inflight, S_IRUGO, part_inflight_show, NULL);
 993 #ifdef CONFIG_FAIL_MAKE_REQUEST
 994 static struct device_attribute dev_attr_fail =
 995         __ATTR(make-it-fail, S_IRUGO|S_IWUSR, part_fail_show, part_fail_store);
 996 #endif
 997 #ifdef CONFIG_FAIL_IO_TIMEOUT
 998 static struct device_attribute dev_attr_fail_timeout =
 999         __ATTR(io-timeout-fail,  S_IRUGO|S_IWUSR, part_timeout_show,
1000                 part_timeout_store);
1001 #endif
1002 
1003 static struct attribute *disk_attrs[] = {
1004         &dev_attr_range.attr,
1005         &dev_attr_ext_range.attr,
1006         &dev_attr_removable.attr,
1007         &dev_attr_ro.attr,
1008         &dev_attr_size.attr,
1009         &dev_attr_alignment_offset.attr,
1010         &dev_attr_discard_alignment.attr,
1011         &dev_attr_capability.attr,
1012         &dev_attr_stat.attr,
1013         &dev_attr_inflight.attr,
1014 #ifdef CONFIG_FAIL_MAKE_REQUEST
1015         &dev_attr_fail.attr,
1016 #endif
1017 #ifdef CONFIG_FAIL_IO_TIMEOUT
1018         &dev_attr_fail_timeout.attr,
1019 #endif
1020         NULL
1021 };
1022 
1023 static struct attribute_group disk_attr_group = {
1024         .attrs = disk_attrs,
1025 };
1026 
1027 static const struct attribute_group *disk_attr_groups[] = {
1028         &disk_attr_group,
1029         NULL
1030 };
1031 
1032 /**
1033  * disk_replace_part_tbl - replace disk->part_tbl in RCU-safe way
1034  * @disk: disk to replace part_tbl for
1035  * @new_ptbl: new part_tbl to install
1036  *
1037  * Replace disk->part_tbl with @new_ptbl in RCU-safe way.  The
1038  * original ptbl is freed using RCU callback.
1039  *
1040  * LOCKING:
1041  * Matching bd_mutx locked.
1042  */
1043 static void disk_replace_part_tbl(struct gendisk *disk,
     /* [previous][next][first][last][top][bottom][index][help] [+1043 block/genhd.c] */
1044                                   struct disk_part_tbl *new_ptbl)
1045 {
1046         struct disk_part_tbl *old_ptbl = disk->part_tbl;
1047 
1048         rcu_assign_pointer(disk->part_tbl, new_ptbl);
1049 
1050         if (old_ptbl) {
1051                 rcu_assign_pointer(old_ptbl->last_lookup, NULL);
1052                 kfree_rcu(old_ptbl, rcu_head);
1053         }
1054 }
1055 
1056 /**
1057  * disk_expand_part_tbl - expand disk->part_tbl
1058  * @disk: disk to expand part_tbl for
1059  * @partno: expand such that this partno can fit in
1060  *
1061  * Expand disk->part_tbl such that @partno can fit in.  disk->part_tbl
1062  * uses RCU to allow unlocked dereferencing for stats and other stuff.
1063  *
1064  * LOCKING:
1065  * Matching bd_mutex locked, might sleep.
1066  *
1067  * RETURNS:
1068  * 0 on success, -errno on failure.
1069  */
1070 int disk_expand_part_tbl(struct gendisk *disk, int partno)
     /* [previous][next][first][last][top][bottom][index][help] [+1070 block/genhd.c] */
1071 {
1072         struct disk_part_tbl *old_ptbl = disk->part_tbl;
1073         struct disk_part_tbl *new_ptbl;
1074         int len = old_ptbl ? old_ptbl->len : 0;
1075         int i, target;
1076         size_t size;
1077 
1078         /*
1079          * check for int overflow, since we can get here from blkpg_ioctl()
1080          * with a user passed 'partno'.
1081          */
1082         target = partno + 1;
1083         if (target < 0)
1084                 return -EINVAL;
1085 
1086         /* disk_max_parts() is zero during initialization, ignore if so */
1087         if (disk_max_parts(disk) && target > disk_max_parts(disk))
1088                 return -EINVAL;
1089 
1090         if (target <= len)
1091                 return 0;
1092 
1093         size = sizeof(*new_ptbl) + target * sizeof(new_ptbl->part[0]);
1094         new_ptbl = kzalloc_node(size, GFP_KERNEL, disk->node_id);
1095         if (!new_ptbl)
1096                 return -ENOMEM;
1097 
1098         new_ptbl->len = target;
1099 
1100         for (i = 0; i < len; i++)
1101                 rcu_assign_pointer(new_ptbl->part[i], old_ptbl->part[i]);
1102 
1103         disk_replace_part_tbl(disk, new_ptbl);
1104         return 0;
1105 }
1106 
1107 static void disk_release(struct device *dev)
     /* [previous][next][first][last][top][bottom][index][help] [+1107 block/genhd.c] */
1108 {
1109         struct gendisk *disk = dev_to_disk(dev);
1110 
1111         blk_free_devt(dev->devt);
1112         disk_release_events(disk);
1113         kfree(disk->random);
1114         disk_replace_part_tbl(disk, NULL);
1115         hd_free_part(&disk->part0);
1116         if (disk->queue)
1117                 blk_put_queue(disk->queue);
1118         kfree(disk);
1119 }
1120 struct class block_class = {
1121         .name           = "block",
1122 };
1123 
1124 static char *block_devnode(struct device *dev, umode_t *mode,
     /* [previous][next][first][last][top][bottom][index][help] [+1124 block/genhd.c] */
1125                            kuid_t *uid, kgid_t *gid)
1126 {
1127         struct gendisk *disk = dev_to_disk(dev);
1128 
1129         if (disk->devnode)
1130                 return disk->devnode(disk, mode);
1131         return NULL;
1132 }
1133 
1134 static struct device_type disk_type = {
1135         .name           = "disk",
1136         .groups         = disk_attr_groups,
1137         .release        = disk_release,
1138         .devnode        = block_devnode,
1139 };
1140 
1141 #ifdef CONFIG_PROC_FS
1142 /*
1143  * aggregate disk stat collector.  Uses the same stats that the sysfs
1144  * entries do, above, but makes them available through one seq_file.
1145  *
1146  * The output looks suspiciously like /proc/partitions with a bunch of
1147  * extra fields.
1148  */
1149 static int diskstats_show(struct seq_file *seqf, void *v)
     /* [previous][next][first][last][top][bottom][index][help] [+1149 block/genhd.c] */
1150 {
1151         struct gendisk *gp = v;
1152         struct disk_part_iter piter;
1153         struct hd_struct *hd;
1154         char buf[BDEVNAME_SIZE];
1155         int cpu;
1156 
1157         /*
1158         if (&disk_to_dev(gp)->kobj.entry == block_class.devices.next)
1159                 seq_puts(seqf,  "major minor name"
1160                                 "     rio rmerge rsect ruse wio wmerge "
1161                                 "wsect wuse running use aveq"
1162                                 "\n\n");
1163         */
1164 
1165         disk_part_iter_init(&piter, gp, DISK_PITER_INCL_EMPTY_PART0);
1166         while ((hd = disk_part_iter_next(&piter))) {
1167                 cpu = part_stat_lock();
1168                 part_round_stats(cpu, hd);
1169                 part_stat_unlock();
1170                 seq_printf(seqf, "%4d %7d %s %lu %lu %lu "
1171                            "%u %lu %lu %lu %u %u %u %u\n",
1172                            MAJOR(part_devt(hd)), MINOR(part_devt(hd)),
1173                            disk_name(gp, hd->partno, buf),
1174                            part_stat_read(hd, ios[READ]),
1175                            part_stat_read(hd, merges[READ]),
1176                            part_stat_read(hd, sectors[READ]),
1177                            jiffies_to_msecs(part_stat_read(hd, ticks[READ])),
1178                            part_stat_read(hd, ios[WRITE]),
1179                            part_stat_read(hd, merges[WRITE]),
1180                            part_stat_read(hd, sectors[WRITE]),
1181                            jiffies_to_msecs(part_stat_read(hd, ticks[WRITE])),
1182                            part_in_flight(hd),
1183                            jiffies_to_msecs(part_stat_read(hd, io_ticks)),
1184                            jiffies_to_msecs(part_stat_read(hd, time_in_queue))
1185                         );
1186         }
1187         disk_part_iter_exit(&piter);
1188 
1189         return 0;
1190 }
1191 
1192 static const struct seq_operations diskstats_op = {
1193         .start  = disk_seqf_start,
1194         .next   = disk_seqf_next,
1195         .stop   = disk_seqf_stop,
1196         .show   = diskstats_show
1197 };
1198 
1199 static int diskstats_open(struct inode *inode, struct file *file)
     /* [previous][next][first][last][top][bottom][index][help] [+1199 block/genhd.c] */
1200 {
1201         return seq_open(file, &diskstats_op);
1202 }
1203 
1204 static const struct file_operations proc_diskstats_operations = {
1205         .open           = diskstats_open,
1206         .read           = seq_read,
1207         .llseek         = seq_lseek,
1208         .release        = seq_release,
1209 };
1210 
1211 static int __init proc_genhd_init(void)
     /* [previous][next][first][last][top][bottom][index][help] [+1211 block/genhd.c] */
1212 {
1213         proc_create("diskstats", 0, NULL, &proc_diskstats_operations);
1214         proc_create("partitions", 0, NULL, &proc_partitions_operations);
1215         return 0;
1216 }
1217 module_init(proc_genhd_init);
1218 #endif /* CONFIG_PROC_FS */
1219 
1220 dev_t blk_lookup_devt(const char *name, int partno)
     /* [previous][next][first][last][top][bottom][index][help] [+1220 block/genhd.c] */
1221 {
1222         dev_t devt = MKDEV(0, 0);
1223         struct class_dev_iter iter;
1224         struct device *dev;
1225 
1226         class_dev_iter_init(&iter, &block_class, NULL, &disk_type);
1227         while ((dev = class_dev_iter_next(&iter))) {
1228                 struct gendisk *disk = dev_to_disk(dev);
1229                 struct hd_struct *part;
1230 
1231                 if (strcmp(dev_name(dev), name))
1232                         continue;
1233 
1234                 if (partno < disk->minors) {
1235                         /* We need to return the right devno, even
1236                          * if the partition doesn't exist yet.
1237                          */
1238                         devt = MKDEV(MAJOR(dev->devt),
1239                                      MINOR(dev->devt) + partno);
1240                         break;
1241                 }
1242                 part = disk_get_part(disk, partno);
1243                 if (part) {
1244                         devt = part_devt(part);
1245                         disk_put_part(part);
1246                         break;
1247                 }
1248                 disk_put_part(part);
1249         }
1250         class_dev_iter_exit(&iter);
1251         return devt;
1252 }
1253 EXPORT_SYMBOL(blk_lookup_devt);
1254 
1255 struct gendisk *alloc_disk(int minors)
     /* [previous][next][first][last][top][bottom][index][help] [+1255 block/genhd.c] */
1256 {
1257         return alloc_disk_node(minors, NUMA_NO_NODE);
1258 }
1259 EXPORT_SYMBOL(alloc_disk);
1260 
1261 struct gendisk *alloc_disk_node(int minors, int node_id)
     /* [previous][next][first][last][top][bottom][index][help] [+1261 block/genhd.c] */
1262 {
1263         struct gendisk *disk;
1264 
1265         disk = kzalloc_node(sizeof(struct gendisk), GFP_KERNEL, node_id);
1266         if (disk) {
1267                 if (!init_part_stats(&disk->part0)) {
1268                         kfree(disk);
1269                         return NULL;
1270                 }
1271                 disk->node_id = node_id;
1272                 if (disk_expand_part_tbl(disk, 0)) {
1273                         free_part_stats(&disk->part0);
1274                         kfree(disk);
1275                         return NULL;
1276                 }
1277                 disk->part_tbl->part[0] = &disk->part0;
1278 
1279                 /*
1280                  * set_capacity() and get_capacity() currently don't use
1281                  * seqcounter to read/update the part0->nr_sects. Still init
1282                  * the counter as we can read the sectors in IO submission
1283                  * patch using seqence counters.
1284                  *
1285                  * TODO: Ideally set_capacity() and get_capacity() should be
1286                  * converted to make use of bd_mutex and sequence counters.
1287                  */
1288                 seqcount_init(&disk->part0.nr_sects_seq);
1289                 if (hd_ref_init(&disk->part0)) {
1290                         hd_free_part(&disk->part0);
1291                         kfree(disk);
1292                         return NULL;
1293                 }
1294 
1295                 disk->minors = minors;
1296                 rand_initialize_disk(disk);
1297                 disk_to_dev(disk)->class = &block_class;
1298                 disk_to_dev(disk)->type = &disk_type;
1299                 device_initialize(disk_to_dev(disk));
1300         }
1301         return disk;
1302 }
1303 EXPORT_SYMBOL(alloc_disk_node);
1304 
1305 struct kobject *get_disk(struct gendisk *disk)
     /* [previous][next][first][last][top][bottom][index][help] [+1305 block/genhd.c] */
1306 {
1307         struct module *owner;
1308         struct kobject *kobj;
1309 
1310         if (!disk->fops)
1311                 return NULL;
1312         owner = disk->fops->owner;
1313         if (owner && !try_module_get(owner))
1314                 return NULL;
1315         kobj = kobject_get(&disk_to_dev(disk)->kobj);
1316         if (kobj == NULL) {
1317                 module_put(owner);
1318                 return NULL;
1319         }
1320         return kobj;
1321 
1322 }
1323 
1324 EXPORT_SYMBOL(get_disk);
1325 
1326 void put_disk(struct gendisk *disk)
     /* [previous][next][first][last][top][bottom][index][help] [+1326 block/genhd.c] */
1327 {
1328         if (disk)
1329                 kobject_put(&disk_to_dev(disk)->kobj);
1330 }
1331 
1332 EXPORT_SYMBOL(put_disk);
1333 
1334 static void set_disk_ro_uevent(struct gendisk *gd, int ro)
     /* [previous][next][first][last][top][bottom][index][help] [+1334 block/genhd.c] */
1335 {
1336         char event[] = "DISK_RO=1";
1337         char *envp[] = { event, NULL };
1338 
1339         if (!ro)
1340                 event[8] = '0';
1341         kobject_uevent_env(&disk_to_dev(gd)->kobj, KOBJ_CHANGE, envp);
1342 }
1343 
1344 void set_device_ro(struct block_device *bdev, int flag)
     /* [previous][next][first][last][top][bottom][index][help] [+1344 block/genhd.c] */
1345 {
1346         bdev->bd_part->policy = flag;
1347 }
1348 
1349 EXPORT_SYMBOL(set_device_ro);
1350 
1351 void set_disk_ro(struct gendisk *disk, int flag)
     /* [previous][next][first][last][top][bottom][index][help] [+1351 block/genhd.c] */
1352 {
1353         struct disk_part_iter piter;
1354         struct hd_struct *part;
1355 
1356         if (disk->part0.policy != flag) {
1357                 set_disk_ro_uevent(disk, flag);
1358                 disk->part0.policy = flag;
1359         }
1360 
1361         disk_part_iter_init(&piter, disk, DISK_PITER_INCL_EMPTY);
1362         while ((part = disk_part_iter_next(&piter)))
1363                 part->policy = flag;
1364         disk_part_iter_exit(&piter);
1365 }
1366 
1367 EXPORT_SYMBOL(set_disk_ro);
1368 
1369 int bdev_read_only(struct block_device *bdev)
     /* [previous][next][first][last][top][bottom][index][help] [+1369 block/genhd.c] */
1370 {
1371         if (!bdev)
1372                 return 0;
1373         return bdev->bd_part->policy;
1374 }
1375 
1376 EXPORT_SYMBOL(bdev_read_only);
1377 
1378 int invalidate_partition(struct gendisk *disk, int partno)
     /* [previous][next][first][last][top][bottom][index][help] [+1378 block/genhd.c] */
1379 {
1380         int res = 0;
1381         struct block_device *bdev = bdget_disk(disk, partno);
1382         if (bdev) {
1383                 fsync_bdev(bdev);
1384                 res = __invalidate_device(bdev, true);
1385                 bdput(bdev);
1386         }
1387         return res;
1388 }
1389 
1390 EXPORT_SYMBOL(invalidate_partition);
1391 
1392 /*
1393  * Disk events - monitor disk events like media change and eject request.
1394  */
1395 struct disk_events {
1396         struct list_head        node;           /* all disk_event's */
1397         struct gendisk          *disk;          /* the associated disk */
1398         spinlock_t              lock;
1399 
1400         struct mutex            block_mutex;    /* protects blocking */
1401         int                     block;          /* event blocking depth */
1402         unsigned int            pending;        /* events already sent out */
1403         unsigned int            clearing;       /* events being cleared */
1404 
1405         long                    poll_msecs;     /* interval, -1 for default */
1406         struct delayed_work     dwork;
1407 };
1408 
1409 static const char *disk_events_strs[] = {
1410         [ilog2(DISK_EVENT_MEDIA_CHANGE)]        = "media_change",
1411         [ilog2(DISK_EVENT_EJECT_REQUEST)]       = "eject_request",
1412 };
1413 
1414 static char *disk_uevents[] = {
1415         [ilog2(DISK_EVENT_MEDIA_CHANGE)]        = "DISK_MEDIA_CHANGE=1",
1416         [ilog2(DISK_EVENT_EJECT_REQUEST)]       = "DISK_EJECT_REQUEST=1",
1417 };
1418 
1419 /* list of all disk_events */
1420 static DEFINE_MUTEX(disk_events_mutex);
1421 static LIST_HEAD(disk_events);
1422 
1423 /* disable in-kernel polling by default */
1424 static unsigned long disk_events_dfl_poll_msecs = 0;
1425 
1426 static unsigned long disk_events_poll_jiffies(struct gendisk *disk)
     /* [previous][next][first][last][top][bottom][index][help] [+1426 block/genhd.c] */
1427 {
1428         struct disk_events *ev = disk->ev;
1429         long intv_msecs = 0;
1430 
1431         /*
1432          * If device-specific poll interval is set, always use it.  If
1433          * the default is being used, poll iff there are events which
1434          * can't be monitored asynchronously.
1435          */
1436         if (ev->poll_msecs >= 0)
1437                 intv_msecs = ev->poll_msecs;
1438         else if (disk->events & ~disk->async_events)
1439                 intv_msecs = disk_events_dfl_poll_msecs;
1440 
1441         return msecs_to_jiffies(intv_msecs);
1442 }
1443 
1444 /**
1445  * disk_block_events - block and flush disk event checking
1446  * @disk: disk to block events for
1447  *
1448  * On return from this function, it is guaranteed that event checking
1449  * isn't in progress and won't happen until unblocked by
1450  * disk_unblock_events().  Events blocking is counted and the actual
1451  * unblocking happens after the matching number of unblocks are done.
1452  *
1453  * Note that this intentionally does not block event checking from
1454  * disk_clear_events().
1455  *
1456  * CONTEXT:
1457  * Might sleep.
1458  */
1459 void disk_block_events(struct gendisk *disk)
     /* [previous][next][first][last][top][bottom][index][help] [+1459 block/genhd.c] */
1460 {
1461         struct disk_events *ev = disk->ev;
1462         unsigned long flags;
1463         bool cancel;
1464 
1465         if (!ev)
1466                 return;
1467 
1468         /*
1469          * Outer mutex ensures that the first blocker completes canceling
1470          * the event work before further blockers are allowed to finish.
1471          */
1472         mutex_lock(&ev->block_mutex);
1473 
1474         spin_lock_irqsave(&ev->lock, flags);
1475         cancel = !ev->block++;
1476         spin_unlock_irqrestore(&ev->lock, flags);
1477 
1478         if (cancel)
1479                 cancel_delayed_work_sync(&disk->ev->dwork);
1480 
1481         mutex_unlock(&ev->block_mutex);
1482 }
1483 
1484 static void __disk_unblock_events(struct gendisk *disk, bool check_now)
     /* [previous][next][first][last][top][bottom][index][help] [+1484 block/genhd.c] */
1485 {
1486         struct disk_events *ev = disk->ev;
1487         unsigned long intv;
1488         unsigned long flags;
1489 
1490         spin_lock_irqsave(&ev->lock, flags);
1491 
1492         if (WARN_ON_ONCE(ev->block <= 0))
1493                 goto out_unlock;
1494 
1495         if (--ev->block)
1496                 goto out_unlock;
1497 
1498         /*
1499          * Not exactly a latency critical operation, set poll timer
1500          * slack to 25% and kick event check.
1501          */
1502         intv = disk_events_poll_jiffies(disk);
1503         set_timer_slack(&ev->dwork.timer, intv / 4);
1504         if (check_now)
1505                 queue_delayed_work(system_freezable_power_efficient_wq,
1506                                 &ev->dwork, 0);
1507         else if (intv)
1508                 queue_delayed_work(system_freezable_power_efficient_wq,
1509                                 &ev->dwork, intv);
1510 out_unlock:
1511         spin_unlock_irqrestore(&ev->lock, flags);
1512 }
1513 
1514 /**
1515  * disk_unblock_events - unblock disk event checking
1516  * @disk: disk to unblock events for
1517  *
1518  * Undo disk_block_events().  When the block count reaches zero, it
1519  * starts events polling if configured.
1520  *
1521  * CONTEXT:
1522  * Don't care.  Safe to call from irq context.
1523  */
1524 void disk_unblock_events(struct gendisk *disk)
     /* [previous][next][first][last][top][bottom][index][help] [+1524 block/genhd.c] */
1525 {
1526         if (disk->ev)
1527                 __disk_unblock_events(disk, false);
1528 }
1529 
1530 /**
1531  * disk_flush_events - schedule immediate event checking and flushing
1532  * @disk: disk to check and flush events for
1533  * @mask: events to flush
1534  *
1535  * Schedule immediate event checking on @disk if not blocked.  Events in
1536  * @mask are scheduled to be cleared from the driver.  Note that this
1537  * doesn't clear the events from @disk->ev.
1538  *
1539  * CONTEXT:
1540  * If @mask is non-zero must be called with bdev->bd_mutex held.
1541  */
1542 void disk_flush_events(struct gendisk *disk, unsigned int mask)
     /* [previous][next][first][last][top][bottom][index][help] [+1542 block/genhd.c] */
1543 {
1544         struct disk_events *ev = disk->ev;
1545 
1546         if (!ev)
1547                 return;
1548 
1549         spin_lock_irq(&ev->lock);
1550         ev->clearing |= mask;
1551         if (!ev->block)
1552                 mod_delayed_work(system_freezable_power_efficient_wq,
1553                                 &ev->dwork, 0);
1554         spin_unlock_irq(&ev->lock);
1555 }
1556 
1557 /**
1558  * disk_clear_events - synchronously check, clear and return pending events
1559  * @disk: disk to fetch and clear events from
1560  * @mask: mask of events to be fetched and cleared
1561  *
1562  * Disk events are synchronously checked and pending events in @mask
1563  * are cleared and returned.  This ignores the block count.
1564  *
1565  * CONTEXT:
1566  * Might sleep.
1567  */
1568 unsigned int disk_clear_events(struct gendisk *disk, unsigned int mask)
     /* [previous][next][first][last][top][bottom][index][help] [+1568 block/genhd.c] */
1569 {
1570         const struct block_device_operations *bdops = disk->fops;
1571         struct disk_events *ev = disk->ev;
1572         unsigned int pending;
1573         unsigned int clearing = mask;
1574 
1575         if (!ev) {
1576                 /* for drivers still using the old ->media_changed method */
1577                 if ((mask & DISK_EVENT_MEDIA_CHANGE) &&
1578                     bdops->media_changed && bdops->media_changed(disk))
1579                         return DISK_EVENT_MEDIA_CHANGE;
1580                 return 0;
1581         }
1582 
1583         disk_block_events(disk);
1584 
1585         /*
1586          * store the union of mask and ev->clearing on the stack so that the
1587          * race with disk_flush_events does not cause ambiguity (ev->clearing
1588          * can still be modified even if events are blocked).
1589          */
1590         spin_lock_irq(&ev->lock);
1591         clearing |= ev->clearing;
1592         ev->clearing = 0;
1593         spin_unlock_irq(&ev->lock);
1594 
1595         disk_check_events(ev, &clearing);
1596         /*
1597          * if ev->clearing is not 0, the disk_flush_events got called in the
1598          * middle of this function, so we want to run the workfn without delay.
1599          */
1600         __disk_unblock_events(disk, ev->clearing ? true : false);
1601 
1602         /* then, fetch and clear pending events */
1603         spin_lock_irq(&ev->lock);
1604         pending = ev->pending & mask;
1605         ev->pending &= ~mask;
1606         spin_unlock_irq(&ev->lock);
1607         WARN_ON_ONCE(clearing & mask);
1608 
1609         return pending;
1610 }
1611 
1612 /*
1613  * Separate this part out so that a different pointer for clearing_ptr can be
1614  * passed in for disk_clear_events.
1615  */
1616 static void disk_events_workfn(struct work_struct *work)
     /* [previous][next][first][last][top][bottom][index][help] [+1616 block/genhd.c] */
1617 {
1618         struct delayed_work *dwork = to_delayed_work(work);
1619         struct disk_events *ev = container_of(dwork, struct disk_events, dwork);
1620 
1621         disk_check_events(ev, &ev->clearing);
1622 }
1623 
1624 static void disk_check_events(struct disk_events *ev,
     /* [previous][next][first][last][top][bottom][index][help] [+1624 block/genhd.c] */
1625                               unsigned int *clearing_ptr)
1626 {
1627         struct gendisk *disk = ev->disk;
1628         char *envp[ARRAY_SIZE(disk_uevents) + 1] = { };
1629         unsigned int clearing = *clearing_ptr;
1630         unsigned int events;
1631         unsigned long intv;
1632         int nr_events = 0, i;
1633 
1634         /* check events */
1635         events = disk->fops->check_events(disk, clearing);
1636 
1637         /* accumulate pending events and schedule next poll if necessary */
1638         spin_lock_irq(&ev->lock);
1639 
1640         events &= ~ev->pending;
1641         ev->pending |= events;
1642         *clearing_ptr &= ~clearing;
1643 
1644         intv = disk_events_poll_jiffies(disk);
1645         if (!ev->block && intv)
1646                 queue_delayed_work(system_freezable_power_efficient_wq,
1647                                 &ev->dwork, intv);
1648 
1649         spin_unlock_irq(&ev->lock);
1650 
1651         /*
1652          * Tell userland about new events.  Only the events listed in
1653          * @disk->events are reported.  Unlisted events are processed the
1654          * same internally but never get reported to userland.
1655          */
1656         for (i = 0; i < ARRAY_SIZE(disk_uevents); i++)
1657                 if (events & disk->events & (1 << i))
1658                         envp[nr_events++] = disk_uevents[i];
1659 
1660         if (nr_events)
1661                 kobject_uevent_env(&disk_to_dev(disk)->kobj, KOBJ_CHANGE, envp);
1662 }
1663 
1664 /*
1665  * A disk events enabled device has the following sysfs nodes under
1666  * its /sys/block/X/ directory.
1667  *
1668  * events               : list of all supported events
1669  * events_async         : list of events which can be detected w/o polling
1670  * events_poll_msecs    : polling interval, 0: disable, -1: system default
1671  */
1672 static ssize_t __disk_events_show(unsigned int events, char *buf)
     /* [previous][next][first][last][top][bottom][index][help] [+1672 block/genhd.c] */
1673 {
1674         const char *delim = "";
1675         ssize_t pos = 0;
1676         int i;
1677 
1678         for (i = 0; i < ARRAY_SIZE(disk_events_strs); i++)
1679                 if (events & (1 << i)) {
1680                         pos += sprintf(buf + pos, "%s%s",
1681                                        delim, disk_events_strs[i]);
1682                         delim = " ";
1683                 }
1684         if (pos)
1685                 pos += sprintf(buf + pos, "\n");
1686         return pos;
1687 }
1688 
1689 static ssize_t disk_events_show(struct device *dev,
     /* [previous][next][first][last][top][bottom][index][help] [+1689 block/genhd.c] */
1690                                 struct device_attribute *attr, char *buf)
1691 {
1692         struct gendisk *disk = dev_to_disk(dev);
1693 
1694         return __disk_events_show(disk->events, buf);
1695 }
1696 
1697 static ssize_t disk_events_async_show(struct device *dev,
     /* [previous][next][first][last][top][bottom][index][help] [+1697 block/genhd.c] */
1698                                       struct device_attribute *attr, char *buf)
1699 {
1700         struct gendisk *disk = dev_to_disk(dev);
1701 
1702         return __disk_events_show(disk->async_events, buf);
1703 }
1704 
1705 static ssize_t disk_events_poll_msecs_show(struct device *dev,
     /* [previous][next][first][last][top][bottom][index][help] [+1705 block/genhd.c] */
1706                                            struct device_attribute *attr,
1707                                            char *buf)
1708 {
1709         struct gendisk *disk = dev_to_disk(dev);
1710 
1711         return sprintf(buf, "%ld\n", disk->ev->poll_msecs);
1712 }
1713 
1714 static ssize_t disk_events_poll_msecs_store(struct device *dev,
     /* [previous][next][first][last][top][bottom][index][help] [+1714 block/genhd.c] */
1715                                             struct device_attribute *attr,
1716                                             const char *buf, size_t count)
1717 {
1718         struct gendisk *disk = dev_to_disk(dev);
1719         long intv;
1720 
1721         if (!count || !sscanf(buf, "%ld", &intv))
1722                 return -EINVAL;
1723 
1724         if (intv < 0 && intv != -1)
1725                 return -EINVAL;
1726 
1727         disk_block_events(disk);
1728         disk->ev->poll_msecs = intv;
1729         __disk_unblock_events(disk, true);
1730 
1731         return count;
1732 }
1733 
1734 static const DEVICE_ATTR(events, S_IRUGO, disk_events_show, NULL);
1735 static const DEVICE_ATTR(events_async, S_IRUGO, disk_events_async_show, NULL);
1736 static const DEVICE_ATTR(events_poll_msecs, S_IRUGO|S_IWUSR,
1737                          disk_events_poll_msecs_show,
1738                          disk_events_poll_msecs_store);
1739 
1740 static const struct attribute *disk_events_attrs[] = {
1741         &dev_attr_events.attr,
1742         &dev_attr_events_async.attr,
1743         &dev_attr_events_poll_msecs.attr,
1744         NULL,
1745 };
1746 
1747 /*
1748  * The default polling interval can be specified by the kernel
1749  * parameter block.events_dfl_poll_msecs which defaults to 0
1750  * (disable).  This can also be modified runtime by writing to
1751  * /sys/module/block/events_dfl_poll_msecs.
1752  */
1753 static int disk_events_set_dfl_poll_msecs(const char *val,
     /* [previous][next][first][last][top][bottom][index][help] [+1753 block/genhd.c] */
1754                                           const struct kernel_param *kp)
1755 {
1756         struct disk_events *ev;
1757         int ret;
1758 
1759         ret = param_set_ulong(val, kp);
1760         if (ret < 0)
1761                 return ret;
1762 
1763         mutex_lock(&disk_events_mutex);
1764 
1765         list_for_each_entry(ev, &disk_events, node)
1766                 disk_flush_events(ev->disk, 0);
1767 
1768         mutex_unlock(&disk_events_mutex);
1769 
1770         return 0;
1771 }
1772 
1773 static const struct kernel_param_ops disk_events_dfl_poll_msecs_param_ops = {
1774         .set    = disk_events_set_dfl_poll_msecs,
1775         .get    = param_get_ulong,
1776 };
1777 
1778 #undef MODULE_PARAM_PREFIX
1779 #define MODULE_PARAM_PREFIX     "block."
1780 
1781 module_param_cb(events_dfl_poll_msecs, &disk_events_dfl_poll_msecs_param_ops,
1782                 &disk_events_dfl_poll_msecs, 0644);
1783 
1784 /*
1785  * disk_{alloc|add|del|release}_events - initialize and destroy disk_events.
1786  */
1787 static void disk_alloc_events(struct gendisk *disk)
     /* [previous][next][first][last][top][bottom][index][help] [+1787 block/genhd.c] */
1788 {
1789         struct disk_events *ev;
1790 
1791         if (!disk->fops->check_events)
1792                 return;
1793 
1794         ev = kzalloc(sizeof(*ev), GFP_KERNEL);
1795         if (!ev) {
1796                 pr_warn("%s: failed to initialize events\n", disk->disk_name);
1797                 return;
1798         }
1799 
1800         INIT_LIST_HEAD(&ev->node);
1801         ev->disk = disk;
1802         spin_lock_init(&ev->lock);
1803         mutex_init(&ev->block_mutex);
1804         ev->block = 1;
1805         ev->poll_msecs = -1;
1806         INIT_DELAYED_WORK(&ev->dwork, disk_events_workfn);
1807 
1808         disk->ev = ev;
1809 }
1810 
1811 static void disk_add_events(struct gendisk *disk)
     /* [previous][next][first][last][top][bottom][index][help] [+1811 block/genhd.c] */
1812 {
1813         if (!disk->ev)
1814                 return;
1815 
1816         /* FIXME: error handling */
1817         if (sysfs_create_files(&disk_to_dev(disk)->kobj, disk_events_attrs) < 0)
1818                 pr_warn("%s: failed to create sysfs files for events\n",
1819                         disk->disk_name);
1820 
1821         mutex_lock(&disk_events_mutex);
1822         list_add_tail(&disk->ev->node, &disk_events);
1823         mutex_unlock(&disk_events_mutex);
1824 
1825         /*
1826          * Block count is initialized to 1 and the following initial
1827          * unblock kicks it into action.
1828          */
1829         __disk_unblock_events(disk, true);
1830 }
1831 
1832 static void disk_del_events(struct gendisk *disk)
     /* [previous][next][first][last][top][bottom][index][help] [+1832 block/genhd.c] */
1833 {
1834         if (!disk->ev)
1835                 return;
1836 
1837         disk_block_events(disk);
1838 
1839         mutex_lock(&disk_events_mutex);
1840         list_del_init(&disk->ev->node);
1841         mutex_unlock(&disk_events_mutex);
1842 
1843         sysfs_remove_files(&disk_to_dev(disk)->kobj, disk_events_attrs);
1844 }
1845 
1846 static void disk_release_events(struct gendisk *disk)
     /* [previous][next][first][last][top][bottom][index][help] [+1846 block/genhd.c] */
1847 {
1848         /* the block count should be 1 from disk_del_events() */
1849         WARN_ON_ONCE(disk->ev && disk->ev->block != 1);
1850         kfree(disk->ev);
1851 }

/* [previous][next][first][last][top][bottom][index][help] [+1851 block/genhd.c] */