block/genhd.c

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This source file includes following definitions.
part_inc_in_flight
part_dec_in_flight
part_in_flight
part_in_flight_rw
__disk_get_part
disk_get_part
disk_part_iter_init
disk_part_iter_next
disk_part_iter_exit
sector_in_part
disk_map_sector_rcu
major_to_index
blkdev_show
register_blkdev
unregister_blkdev
blk_mangle_minor
blk_alloc_devt
blk_free_devt
blk_invalidate_devt
bdevt_str
blk_register_region
blk_unregister_region
exact_match
exact_lock
register_disk
__device_add_disk
device_add_disk
device_add_disk_no_queue_reg
del_gendisk
disk_badblocks_show
disk_badblocks_store
get_gendisk
bdget_disk
printk_all_partitions
disk_seqf_start
disk_seqf_next
disk_seqf_stop
show_partition_start
show_partition
base_probe
genhd_device_init
disk_range_show
disk_ext_range_show
disk_removable_show
disk_hidden_show
disk_ro_show
disk_capability_show
disk_alignment_offset_show
disk_discard_alignment_show
disk_visible
disk_replace_part_tbl
disk_expand_part_tbl
disk_release
block_devnode
diskstats_show
proc_genhd_init
blk_lookup_devt
__alloc_disk_node
get_disk_and_module
put_disk
put_disk_and_module
set_disk_ro_uevent
set_device_ro
set_disk_ro
bdev_read_only
invalidate_partition
disk_events_poll_jiffies
disk_block_events
__disk_unblock_events
disk_unblock_events
disk_flush_events
disk_clear_events
disk_events_workfn
disk_check_events
__disk_events_show
disk_events_show
disk_events_async_show
disk_events_poll_msecs_show
disk_events_poll_msecs_store
disk_events_set_dfl_poll_msecs
disk_alloc_events
disk_add_events
disk_del_events
disk_release_events
   1 // SPDX-License-Identifier: GPL-2.0
   2 /*
   3  *  gendisk handling
   4  */
   5 
   6 #include <linux/module.h>
   7 #include <linux/fs.h>
   8 #include <linux/genhd.h>
   9 #include <linux/kdev_t.h>
  10 #include <linux/kernel.h>
  11 #include <linux/blkdev.h>
  12 #include <linux/backing-dev.h>
  13 #include <linux/init.h>
  14 #include <linux/spinlock.h>
  15 #include <linux/proc_fs.h>
  16 #include <linux/seq_file.h>
  17 #include <linux/slab.h>
  18 #include <linux/kmod.h>
  19 #include <linux/kobj_map.h>
  20 #include <linux/mutex.h>
  21 #include <linux/idr.h>
  22 #include <linux/log2.h>
  23 #include <linux/pm_runtime.h>
  24 #include <linux/badblocks.h>
  25 
  26 #include "blk.h"
  27 
  28 static DEFINE_MUTEX(block_class_lock);
  29 struct kobject *block_depr;
  30 
  31 /* for extended dynamic devt allocation, currently only one major is used */
  32 #define NR_EXT_DEVT             (1 << MINORBITS)
  33 
  34 /* For extended devt allocation.  ext_devt_lock prevents look up
  35  * results from going away underneath its user.
  36  */
  37 static DEFINE_SPINLOCK(ext_devt_lock);
  38 static DEFINE_IDR(ext_devt_idr);
  39 
  40 static const struct device_type disk_type;
  41 
  42 static void disk_check_events(struct disk_events *ev,
  43                               unsigned int *clearing_ptr);
  44 static void disk_alloc_events(struct gendisk *disk);
  45 static void disk_add_events(struct gendisk *disk);
  46 static void disk_del_events(struct gendisk *disk);
  47 static void disk_release_events(struct gendisk *disk);
  48 
  49 void part_inc_in_flight(struct request_queue *q, struct hd_struct *part, int rw)
  50 {
  51         if (queue_is_mq(q))
  52                 return;
  53 
  54         part_stat_local_inc(part, in_flight[rw]);
  55         if (part->partno)
  56                 part_stat_local_inc(&part_to_disk(part)->part0, in_flight[rw]);
  57 }
  58 
  59 void part_dec_in_flight(struct request_queue *q, struct hd_struct *part, int rw)
  60 {
  61         if (queue_is_mq(q))
  62                 return;
  63 
  64         part_stat_local_dec(part, in_flight[rw]);
  65         if (part->partno)
  66                 part_stat_local_dec(&part_to_disk(part)->part0, in_flight[rw]);
  67 }
  68 
  69 unsigned int part_in_flight(struct request_queue *q, struct hd_struct *part)
  70 {
  71         int cpu;
  72         unsigned int inflight;
  73 
  74         if (queue_is_mq(q)) {
  75                 return blk_mq_in_flight(q, part);
  76         }
  77 
  78         inflight = 0;
  79         for_each_possible_cpu(cpu) {
  80                 inflight += part_stat_local_read_cpu(part, in_flight[0], cpu) +
  81                             part_stat_local_read_cpu(part, in_flight[1], cpu);
  82         }
  83         if ((int)inflight < 0)
  84                 inflight = 0;
  85 
  86         return inflight;
  87 }
  88 
  89 void part_in_flight_rw(struct request_queue *q, struct hd_struct *part,
  90                        unsigned int inflight[2])
  91 {
  92         int cpu;
  93 
  94         if (queue_is_mq(q)) {
  95                 blk_mq_in_flight_rw(q, part, inflight);
  96                 return;
  97         }
  98 
  99         inflight[0] = 0;
 100         inflight[1] = 0;
 101         for_each_possible_cpu(cpu) {
 102                 inflight[0] += part_stat_local_read_cpu(part, in_flight[0], cpu);
 103                 inflight[1] += part_stat_local_read_cpu(part, in_flight[1], cpu);
 104         }
 105         if ((int)inflight[0] < 0)
 106                 inflight[0] = 0;
 107         if ((int)inflight[1] < 0)
 108                 inflight[1] = 0;
 109 }
 110 
 111 struct hd_struct *__disk_get_part(struct gendisk *disk, int partno)
 112 {
 113         struct disk_part_tbl *ptbl = rcu_dereference(disk->part_tbl);
 114 
 115         if (unlikely(partno < 0 || partno >= ptbl->len))
 116                 return NULL;
 117         return rcu_dereference(ptbl->part[partno]);
 118 }
 119 
 120 /**
 121  * disk_get_part - get partition
 122  * @disk: disk to look partition from
 123  * @partno: partition number
 124  *
 125  * Look for partition @partno from @disk.  If found, increment
 126  * reference count and return it.
 127  *
 128  * CONTEXT:
 129  * Don't care.
 130  *
 131  * RETURNS:
 132  * Pointer to the found partition on success, NULL if not found.
 133  */
 134 struct hd_struct *disk_get_part(struct gendisk *disk, int partno)
 135 {
 136         struct hd_struct *part;
 137 
 138         rcu_read_lock();
 139         part = __disk_get_part(disk, partno);
 140         if (part)
 141                 get_device(part_to_dev(part));
 142         rcu_read_unlock();
 143 
 144         return part;
 145 }
 146 EXPORT_SYMBOL_GPL(disk_get_part);
 147 
 148 /**
 149  * disk_part_iter_init - initialize partition iterator
 150  * @piter: iterator to initialize
 151  * @disk: disk to iterate over
 152  * @flags: DISK_PITER_* flags
 153  *
 154  * Initialize @piter so that it iterates over partitions of @disk.
 155  *
 156  * CONTEXT:
 157  * Don't care.
 158  */
 159 void disk_part_iter_init(struct disk_part_iter *piter, struct gendisk *disk,
 160                           unsigned int flags)
 161 {
 162         struct disk_part_tbl *ptbl;
 163 
 164         rcu_read_lock();
 165         ptbl = rcu_dereference(disk->part_tbl);
 166 
 167         piter->disk = disk;
 168         piter->part = NULL;
 169 
 170         if (flags & DISK_PITER_REVERSE)
 171                 piter->idx = ptbl->len - 1;
 172         else if (flags & (DISK_PITER_INCL_PART0 | DISK_PITER_INCL_EMPTY_PART0))
 173                 piter->idx = 0;
 174         else
 175                 piter->idx = 1;
 176 
 177         piter->flags = flags;
 178 
 179         rcu_read_unlock();
 180 }
 181 EXPORT_SYMBOL_GPL(disk_part_iter_init);
 182 
 183 /**
 184  * disk_part_iter_next - proceed iterator to the next partition and return it
 185  * @piter: iterator of interest
 186  *
 187  * Proceed @piter to the next partition and return it.
 188  *
 189  * CONTEXT:
 190  * Don't care.
 191  */
 192 struct hd_struct *disk_part_iter_next(struct disk_part_iter *piter)
 193 {
 194         struct disk_part_tbl *ptbl;
 195         int inc, end;
 196 
 197         /* put the last partition */
 198         disk_put_part(piter->part);
 199         piter->part = NULL;
 200 
 201         /* get part_tbl */
 202         rcu_read_lock();
 203         ptbl = rcu_dereference(piter->disk->part_tbl);
 204 
 205         /* determine iteration parameters */
 206         if (piter->flags & DISK_PITER_REVERSE) {
 207                 inc = -1;
 208                 if (piter->flags & (DISK_PITER_INCL_PART0 |
 209                                     DISK_PITER_INCL_EMPTY_PART0))
 210                         end = -1;
 211                 else
 212                         end = 0;
 213         } else {
 214                 inc = 1;
 215                 end = ptbl->len;
 216         }
 217 
 218         /* iterate to the next partition */
 219         for (; piter->idx != end; piter->idx += inc) {
 220                 struct hd_struct *part;
 221 
 222                 part = rcu_dereference(ptbl->part[piter->idx]);
 223                 if (!part)
 224                         continue;
 225                 if (!part_nr_sects_read(part) &&
 226                     !(piter->flags & DISK_PITER_INCL_EMPTY) &&
 227                     !(piter->flags & DISK_PITER_INCL_EMPTY_PART0 &&
 228                       piter->idx == 0))
 229                         continue;
 230 
 231                 get_device(part_to_dev(part));
 232                 piter->part = part;
 233                 piter->idx += inc;
 234                 break;
 235         }
 236 
 237         rcu_read_unlock();
 238 
 239         return piter->part;
 240 }
 241 EXPORT_SYMBOL_GPL(disk_part_iter_next);
 242 
 243 /**
 244  * disk_part_iter_exit - finish up partition iteration
 245  * @piter: iter of interest
 246  *
 247  * Called when iteration is over.  Cleans up @piter.
 248  *
 249  * CONTEXT:
 250  * Don't care.
 251  */
 252 void disk_part_iter_exit(struct disk_part_iter *piter)
 253 {
 254         disk_put_part(piter->part);
 255         piter->part = NULL;
 256 }
 257 EXPORT_SYMBOL_GPL(disk_part_iter_exit);
 258 
 259 static inline int sector_in_part(struct hd_struct *part, sector_t sector)
 260 {
 261         return part->start_sect <= sector &&
 262                 sector < part->start_sect + part_nr_sects_read(part);
 263 }
 264 
 265 /**
 266  * disk_map_sector_rcu - map sector to partition
 267  * @disk: gendisk of interest
 268  * @sector: sector to map
 269  *
 270  * Find out which partition @sector maps to on @disk.  This is
 271  * primarily used for stats accounting.
 272  *
 273  * CONTEXT:
 274  * RCU read locked.  The returned partition pointer is valid only
 275  * while preemption is disabled.
 276  *
 277  * RETURNS:
 278  * Found partition on success, part0 is returned if no partition matches
 279  */
 280 struct hd_struct *disk_map_sector_rcu(struct gendisk *disk, sector_t sector)
 281 {
 282         struct disk_part_tbl *ptbl;
 283         struct hd_struct *part;
 284         int i;
 285 
 286         ptbl = rcu_dereference(disk->part_tbl);
 287 
 288         part = rcu_dereference(ptbl->last_lookup);
 289         if (part && sector_in_part(part, sector))
 290                 return part;
 291 
 292         for (i = 1; i < ptbl->len; i++) {
 293                 part = rcu_dereference(ptbl->part[i]);
 294 
 295                 if (part && sector_in_part(part, sector)) {
 296                         rcu_assign_pointer(ptbl->last_lookup, part);
 297                         return part;
 298                 }
 299         }
 300         return &disk->part0;
 301 }
 302 EXPORT_SYMBOL_GPL(disk_map_sector_rcu);
 303 
 304 /*
 305  * Can be deleted altogether. Later.
 306  *
 307  */
 308 #define BLKDEV_MAJOR_HASH_SIZE 255
 309 static struct blk_major_name {
 310         struct blk_major_name *next;
 311         int major;
 312         char name[16];
 313 } *major_names[BLKDEV_MAJOR_HASH_SIZE];
 314 
 315 /* index in the above - for now: assume no multimajor ranges */
 316 static inline int major_to_index(unsigned major)
 317 {
 318         return major % BLKDEV_MAJOR_HASH_SIZE;
 319 }
 320 
 321 #ifdef CONFIG_PROC_FS
 322 void blkdev_show(struct seq_file *seqf, off_t offset)
 323 {
 324         struct blk_major_name *dp;
 325 
 326         mutex_lock(&block_class_lock);
 327         for (dp = major_names[major_to_index(offset)]; dp; dp = dp->next)
 328                 if (dp->major == offset)
 329                         seq_printf(seqf, "%3d %s\n", dp->major, dp->name);
 330         mutex_unlock(&block_class_lock);
 331 }
 332 #endif /* CONFIG_PROC_FS */
 333 
 334 /**
 335  * register_blkdev - register a new block device
 336  *
 337  * @major: the requested major device number [1..BLKDEV_MAJOR_MAX-1]. If
 338  *         @major = 0, try to allocate any unused major number.
 339  * @name: the name of the new block device as a zero terminated string
 340  *
 341  * The @name must be unique within the system.
 342  *
 343  * The return value depends on the @major input parameter:
 344  *
 345  *  - if a major device number was requested in range [1..BLKDEV_MAJOR_MAX-1]
 346  *    then the function returns zero on success, or a negative error code
 347  *  - if any unused major number was requested with @major = 0 parameter
 348  *    then the return value is the allocated major number in range
 349  *    [1..BLKDEV_MAJOR_MAX-1] or a negative error code otherwise
 350  *
 351  * See Documentation/admin-guide/devices.txt for the list of allocated
 352  * major numbers.
 353  */
 354 int register_blkdev(unsigned int major, const char *name)
 355 {
 356         struct blk_major_name **n, *p;
 357         int index, ret = 0;
 358 
 359         mutex_lock(&block_class_lock);
 360 
 361         /* temporary */
 362         if (major == 0) {
 363                 for (index = ARRAY_SIZE(major_names)-1; index > 0; index--) {
 364                         if (major_names[index] == NULL)
 365                                 break;
 366                 }
 367 
 368                 if (index == 0) {
 369                         printk("%s: failed to get major for %s\n",
 370                                __func__, name);
 371                         ret = -EBUSY;
 372                         goto out;
 373                 }
 374                 major = index;
 375                 ret = major;
 376         }
 377 
 378         if (major >= BLKDEV_MAJOR_MAX) {
 379                 pr_err("%s: major requested (%u) is greater than the maximum (%u) for %s\n",
 380                        __func__, major, BLKDEV_MAJOR_MAX-1, name);
 381 
 382                 ret = -EINVAL;
 383                 goto out;
 384         }
 385 
 386         p = kmalloc(sizeof(struct blk_major_name), GFP_KERNEL);
 387         if (p == NULL) {
 388                 ret = -ENOMEM;
 389                 goto out;
 390         }
 391 
 392         p->major = major;
 393         strlcpy(p->name, name, sizeof(p->name));
 394         p->next = NULL;
 395         index = major_to_index(major);
 396 
 397         for (n = &major_names[index]; *n; n = &(*n)->next) {
 398                 if ((*n)->major == major)
 399                         break;
 400         }
 401         if (!*n)
 402                 *n = p;
 403         else
 404                 ret = -EBUSY;
 405 
 406         if (ret < 0) {
 407                 printk("register_blkdev: cannot get major %u for %s\n",
 408                        major, name);
 409                 kfree(p);
 410         }
 411 out:
 412         mutex_unlock(&block_class_lock);
 413         return ret;
 414 }
 415 
 416 EXPORT_SYMBOL(register_blkdev);
 417 
 418 void unregister_blkdev(unsigned int major, const char *name)
 419 {
 420         struct blk_major_name **n;
 421         struct blk_major_name *p = NULL;
 422         int index = major_to_index(major);
 423 
 424         mutex_lock(&block_class_lock);
 425         for (n = &major_names[index]; *n; n = &(*n)->next)
 426                 if ((*n)->major == major)
 427                         break;
 428         if (!*n || strcmp((*n)->name, name)) {
 429                 WARN_ON(1);
 430         } else {
 431                 p = *n;
 432                 *n = p->next;
 433         }
 434         mutex_unlock(&block_class_lock);
 435         kfree(p);
 436 }
 437 
 438 EXPORT_SYMBOL(unregister_blkdev);
 439 
 440 static struct kobj_map *bdev_map;
 441 
 442 /**
 443  * blk_mangle_minor - scatter minor numbers apart
 444  * @minor: minor number to mangle
 445  *
 446  * Scatter consecutively allocated @minor number apart if MANGLE_DEVT
 447  * is enabled.  Mangling twice gives the original value.
 448  *
 449  * RETURNS:
 450  * Mangled value.
 451  *
 452  * CONTEXT:
 453  * Don't care.
 454  */
 455 static int blk_mangle_minor(int minor)
 456 {
 457 #ifdef CONFIG_DEBUG_BLOCK_EXT_DEVT
 458         int i;
 459 
 460         for (i = 0; i < MINORBITS / 2; i++) {
 461                 int low = minor & (1 << i);
 462                 int high = minor & (1 << (MINORBITS - 1 - i));
 463                 int distance = MINORBITS - 1 - 2 * i;
 464 
 465                 minor ^= low | high;    /* clear both bits */
 466                 low <<= distance;       /* swap the positions */
 467                 high >>= distance;
 468                 minor |= low | high;    /* and set */
 469         }
 470 #endif
 471         return minor;
 472 }
 473 
 474 /**
 475  * blk_alloc_devt - allocate a dev_t for a partition
 476  * @part: partition to allocate dev_t for
 477  * @devt: out parameter for resulting dev_t
 478  *
 479  * Allocate a dev_t for block device.
 480  *
 481  * RETURNS:
 482  * 0 on success, allocated dev_t is returned in *@devt.  -errno on
 483  * failure.
 484  *
 485  * CONTEXT:
 486  * Might sleep.
 487  */
 488 int blk_alloc_devt(struct hd_struct *part, dev_t *devt)
 489 {
 490         struct gendisk *disk = part_to_disk(part);
 491         int idx;
 492 
 493         /* in consecutive minor range? */
 494         if (part->partno < disk->minors) {
 495                 *devt = MKDEV(disk->major, disk->first_minor + part->partno);
 496                 return 0;
 497         }
 498 
 499         /* allocate ext devt */
 500         idr_preload(GFP_KERNEL);
 501 
 502         spin_lock_bh(&ext_devt_lock);
 503         idx = idr_alloc(&ext_devt_idr, part, 0, NR_EXT_DEVT, GFP_NOWAIT);
 504         spin_unlock_bh(&ext_devt_lock);
 505 
 506         idr_preload_end();
 507         if (idx < 0)
 508                 return idx == -ENOSPC ? -EBUSY : idx;
 509 
 510         *devt = MKDEV(BLOCK_EXT_MAJOR, blk_mangle_minor(idx));
 511         return 0;
 512 }
 513 
 514 /**
 515  * blk_free_devt - free a dev_t
 516  * @devt: dev_t to free
 517  *
 518  * Free @devt which was allocated using blk_alloc_devt().
 519  *
 520  * CONTEXT:
 521  * Might sleep.
 522  */
 523 void blk_free_devt(dev_t devt)
 524 {
 525         if (devt == MKDEV(0, 0))
 526                 return;
 527 
 528         if (MAJOR(devt) == BLOCK_EXT_MAJOR) {
 529                 spin_lock_bh(&ext_devt_lock);
 530                 idr_remove(&ext_devt_idr, blk_mangle_minor(MINOR(devt)));
 531                 spin_unlock_bh(&ext_devt_lock);
 532         }
 533 }
 534 
 535 /*
 536  * We invalidate devt by assigning NULL pointer for devt in idr.
 537  */
 538 void blk_invalidate_devt(dev_t devt)
 539 {
 540         if (MAJOR(devt) == BLOCK_EXT_MAJOR) {
 541                 spin_lock_bh(&ext_devt_lock);
 542                 idr_replace(&ext_devt_idr, NULL, blk_mangle_minor(MINOR(devt)));
 543                 spin_unlock_bh(&ext_devt_lock);
 544         }
 545 }
 546 
 547 static char *bdevt_str(dev_t devt, char *buf)
 548 {
 549         if (MAJOR(devt) <= 0xff && MINOR(devt) <= 0xff) {
 550                 char tbuf[BDEVT_SIZE];
 551                 snprintf(tbuf, BDEVT_SIZE, "%02x%02x", MAJOR(devt), MINOR(devt));
 552                 snprintf(buf, BDEVT_SIZE, "%-9s", tbuf);
 553         } else
 554                 snprintf(buf, BDEVT_SIZE, "%03x:%05x", MAJOR(devt), MINOR(devt));
 555 
 556         return buf;
 557 }
 558 
 559 /*
 560  * Register device numbers dev..(dev+range-1)
 561  * range must be nonzero
 562  * The hash chain is sorted on range, so that subranges can override.
 563  */
 564 void blk_register_region(dev_t devt, unsigned long range, struct module *module,
 565                          struct kobject *(*probe)(dev_t, int *, void *),
 566                          int (*lock)(dev_t, void *), void *data)
 567 {
 568         kobj_map(bdev_map, devt, range, module, probe, lock, data);
 569 }
 570 
 571 EXPORT_SYMBOL(blk_register_region);
 572 
 573 void blk_unregister_region(dev_t devt, unsigned long range)
 574 {
 575         kobj_unmap(bdev_map, devt, range);
 576 }
 577 
 578 EXPORT_SYMBOL(blk_unregister_region);
 579 
 580 static struct kobject *exact_match(dev_t devt, int *partno, void *data)
 581 {
 582         struct gendisk *p = data;
 583 
 584         return &disk_to_dev(p)->kobj;
 585 }
 586 
 587 static int exact_lock(dev_t devt, void *data)
 588 {
 589         struct gendisk *p = data;
 590 
 591         if (!get_disk_and_module(p))
 592                 return -1;
 593         return 0;
 594 }
 595 
 596 static void register_disk(struct device *parent, struct gendisk *disk,
 597                           const struct attribute_group **groups)
 598 {
 599         struct device *ddev = disk_to_dev(disk);
 600         struct block_device *bdev;
 601         struct disk_part_iter piter;
 602         struct hd_struct *part;
 603         int err;
 604 
 605         ddev->parent = parent;
 606 
 607         dev_set_name(ddev, "%s", disk->disk_name);
 608 
 609         /* delay uevents, until we scanned partition table */
 610         dev_set_uevent_suppress(ddev, 1);
 611 
 612         if (groups) {
 613                 WARN_ON(ddev->groups);
 614                 ddev->groups = groups;
 615         }
 616         if (device_add(ddev))
 617                 return;
 618         if (!sysfs_deprecated) {
 619                 err = sysfs_create_link(block_depr, &ddev->kobj,
 620                                         kobject_name(&ddev->kobj));
 621                 if (err) {
 622                         device_del(ddev);
 623                         return;
 624                 }
 625         }
 626 
 627         /*
 628          * avoid probable deadlock caused by allocating memory with
 629          * GFP_KERNEL in runtime_resume callback of its all ancestor
 630          * devices
 631          */
 632         pm_runtime_set_memalloc_noio(ddev, true);
 633 
 634         disk->part0.holder_dir = kobject_create_and_add("holders", &ddev->kobj);
 635         disk->slave_dir = kobject_create_and_add("slaves", &ddev->kobj);
 636 
 637         if (disk->flags & GENHD_FL_HIDDEN) {
 638                 dev_set_uevent_suppress(ddev, 0);
 639                 return;
 640         }
 641 
 642         /* No minors to use for partitions */
 643         if (!disk_part_scan_enabled(disk))
 644                 goto exit;
 645 
 646         /* No such device (e.g., media were just removed) */
 647         if (!get_capacity(disk))
 648                 goto exit;
 649 
 650         bdev = bdget_disk(disk, 0);
 651         if (!bdev)
 652                 goto exit;
 653 
 654         bdev->bd_invalidated = 1;
 655         err = blkdev_get(bdev, FMODE_READ, NULL);
 656         if (err < 0)
 657                 goto exit;
 658         blkdev_put(bdev, FMODE_READ);
 659 
 660 exit:
 661         /* announce disk after possible partitions are created */
 662         dev_set_uevent_suppress(ddev, 0);
 663         kobject_uevent(&ddev->kobj, KOBJ_ADD);
 664 
 665         /* announce possible partitions */
 666         disk_part_iter_init(&piter, disk, 0);
 667         while ((part = disk_part_iter_next(&piter)))
 668                 kobject_uevent(&part_to_dev(part)->kobj, KOBJ_ADD);
 669         disk_part_iter_exit(&piter);
 670 
 671         if (disk->queue->backing_dev_info->dev) {
 672                 err = sysfs_create_link(&ddev->kobj,
 673                           &disk->queue->backing_dev_info->dev->kobj,
 674                           "bdi");
 675                 WARN_ON(err);
 676         }
 677 }
 678 
 679 /**
 680  * __device_add_disk - add disk information to kernel list
 681  * @parent: parent device for the disk
 682  * @disk: per-device partitioning information
 683  * @groups: Additional per-device sysfs groups
 684  * @register_queue: register the queue if set to true
 685  *
 686  * This function registers the partitioning information in @disk
 687  * with the kernel.
 688  *
 689  * FIXME: error handling
 690  */
 691 static void __device_add_disk(struct device *parent, struct gendisk *disk,
 692                               const struct attribute_group **groups,
 693                               bool register_queue)
 694 {
 695         dev_t devt;
 696         int retval;
 697 
 698         /*
 699          * The disk queue should now be all set with enough information about
 700          * the device for the elevator code to pick an adequate default
 701          * elevator if one is needed, that is, for devices requesting queue
 702          * registration.
 703          */
 704         if (register_queue)
 705                 elevator_init_mq(disk->queue);
 706 
 707         /* minors == 0 indicates to use ext devt from part0 and should
 708          * be accompanied with EXT_DEVT flag.  Make sure all
 709          * parameters make sense.
 710          */
 711         WARN_ON(disk->minors && !(disk->major || disk->first_minor));
 712         WARN_ON(!disk->minors &&
 713                 !(disk->flags & (GENHD_FL_EXT_DEVT | GENHD_FL_HIDDEN)));
 714 
 715         disk->flags |= GENHD_FL_UP;
 716 
 717         retval = blk_alloc_devt(&disk->part0, &devt);
 718         if (retval) {
 719                 WARN_ON(1);
 720                 return;
 721         }
 722         disk->major = MAJOR(devt);
 723         disk->first_minor = MINOR(devt);
 724 
 725         disk_alloc_events(disk);
 726 
 727         if (disk->flags & GENHD_FL_HIDDEN) {
 728                 /*
 729                  * Don't let hidden disks show up in /proc/partitions,
 730                  * and don't bother scanning for partitions either.
 731                  */
 732                 disk->flags |= GENHD_FL_SUPPRESS_PARTITION_INFO;
 733                 disk->flags |= GENHD_FL_NO_PART_SCAN;
 734         } else {
 735                 int ret;
 736 
 737                 /* Register BDI before referencing it from bdev */
 738                 disk_to_dev(disk)->devt = devt;
 739                 ret = bdi_register_owner(disk->queue->backing_dev_info,
 740                                                 disk_to_dev(disk));
 741                 WARN_ON(ret);
 742                 blk_register_region(disk_devt(disk), disk->minors, NULL,
 743                                     exact_match, exact_lock, disk);
 744         }
 745         register_disk(parent, disk, groups);
 746         if (register_queue)
 747                 blk_register_queue(disk);
 748 
 749         /*
 750          * Take an extra ref on queue which will be put on disk_release()
 751          * so that it sticks around as long as @disk is there.
 752          */
 753         WARN_ON_ONCE(!blk_get_queue(disk->queue));
 754 
 755         disk_add_events(disk);
 756         blk_integrity_add(disk);
 757 }
 758 
 759 void device_add_disk(struct device *parent, struct gendisk *disk,
 760                      const struct attribute_group **groups)
 761 
 762 {
 763         __device_add_disk(parent, disk, groups, true);
 764 }
 765 EXPORT_SYMBOL(device_add_disk);
 766 
 767 void device_add_disk_no_queue_reg(struct device *parent, struct gendisk *disk)
 768 {
 769         __device_add_disk(parent, disk, NULL, false);
 770 }
 771 EXPORT_SYMBOL(device_add_disk_no_queue_reg);
 772 
 773 void del_gendisk(struct gendisk *disk)
 774 {
 775         struct disk_part_iter piter;
 776         struct hd_struct *part;
 777 
 778         blk_integrity_del(disk);
 779         disk_del_events(disk);
 780 
 781         /*
 782          * Block lookups of the disk until all bdevs are unhashed and the
 783          * disk is marked as dead (GENHD_FL_UP cleared).
 784          */
 785         down_write(&disk->lookup_sem);
 786         /* invalidate stuff */
 787         disk_part_iter_init(&piter, disk,
 788                              DISK_PITER_INCL_EMPTY | DISK_PITER_REVERSE);
 789         while ((part = disk_part_iter_next(&piter))) {
 790                 invalidate_partition(disk, part->partno);
 791                 bdev_unhash_inode(part_devt(part));
 792                 delete_partition(disk, part->partno);
 793         }
 794         disk_part_iter_exit(&piter);
 795 
 796         invalidate_partition(disk, 0);
 797         bdev_unhash_inode(disk_devt(disk));
 798         set_capacity(disk, 0);
 799         disk->flags &= ~GENHD_FL_UP;
 800         up_write(&disk->lookup_sem);
 801 
 802         if (!(disk->flags & GENHD_FL_HIDDEN))
 803                 sysfs_remove_link(&disk_to_dev(disk)->kobj, "bdi");
 804         if (disk->queue) {
 805                 /*
 806                  * Unregister bdi before releasing device numbers (as they can
 807                  * get reused and we'd get clashes in sysfs).
 808                  */
 809                 if (!(disk->flags & GENHD_FL_HIDDEN))
 810                         bdi_unregister(disk->queue->backing_dev_info);
 811                 blk_unregister_queue(disk);
 812         } else {
 813                 WARN_ON(1);
 814         }
 815 
 816         if (!(disk->flags & GENHD_FL_HIDDEN))
 817                 blk_unregister_region(disk_devt(disk), disk->minors);
 818         /*
 819          * Remove gendisk pointer from idr so that it cannot be looked up
 820          * while RCU period before freeing gendisk is running to prevent
 821          * use-after-free issues. Note that the device number stays
 822          * "in-use" until we really free the gendisk.
 823          */
 824         blk_invalidate_devt(disk_devt(disk));
 825 
 826         kobject_put(disk->part0.holder_dir);
 827         kobject_put(disk->slave_dir);
 828 
 829         part_stat_set_all(&disk->part0, 0);
 830         disk->part0.stamp = 0;
 831         if (!sysfs_deprecated)
 832                 sysfs_remove_link(block_depr, dev_name(disk_to_dev(disk)));
 833         pm_runtime_set_memalloc_noio(disk_to_dev(disk), false);
 834         device_del(disk_to_dev(disk));
 835 }
 836 EXPORT_SYMBOL(del_gendisk);
 837 
 838 /* sysfs access to bad-blocks list. */
 839 static ssize_t disk_badblocks_show(struct device *dev,
 840                                         struct device_attribute *attr,
 841                                         char *page)
 842 {
 843         struct gendisk *disk = dev_to_disk(dev);
 844 
 845         if (!disk->bb)
 846                 return sprintf(page, "\n");
 847 
 848         return badblocks_show(disk->bb, page, 0);
 849 }
 850 
 851 static ssize_t disk_badblocks_store(struct device *dev,
 852                                         struct device_attribute *attr,
 853                                         const char *page, size_t len)
 854 {
 855         struct gendisk *disk = dev_to_disk(dev);
 856 
 857         if (!disk->bb)
 858                 return -ENXIO;
 859 
 860         return badblocks_store(disk->bb, page, len, 0);
 861 }
 862 
 863 /**
 864  * get_gendisk - get partitioning information for a given device
 865  * @devt: device to get partitioning information for
 866  * @partno: returned partition index
 867  *
 868  * This function gets the structure containing partitioning
 869  * information for the given device @devt.
 870  */
 871 struct gendisk *get_gendisk(dev_t devt, int *partno)
 872 {
 873         struct gendisk *disk = NULL;
 874 
 875         if (MAJOR(devt) != BLOCK_EXT_MAJOR) {
 876                 struct kobject *kobj;
 877 
 878                 kobj = kobj_lookup(bdev_map, devt, partno);
 879                 if (kobj)
 880                         disk = dev_to_disk(kobj_to_dev(kobj));
 881         } else {
 882                 struct hd_struct *part;
 883 
 884                 spin_lock_bh(&ext_devt_lock);
 885                 part = idr_find(&ext_devt_idr, blk_mangle_minor(MINOR(devt)));
 886                 if (part && get_disk_and_module(part_to_disk(part))) {
 887                         *partno = part->partno;
 888                         disk = part_to_disk(part);
 889                 }
 890                 spin_unlock_bh(&ext_devt_lock);
 891         }
 892 
 893         if (!disk)
 894                 return NULL;
 895 
 896         /*
 897          * Synchronize with del_gendisk() to not return disk that is being
 898          * destroyed.
 899          */
 900         down_read(&disk->lookup_sem);
 901         if (unlikely((disk->flags & GENHD_FL_HIDDEN) ||
 902                      !(disk->flags & GENHD_FL_UP))) {
 903                 up_read(&disk->lookup_sem);
 904                 put_disk_and_module(disk);
 905                 disk = NULL;
 906         } else {
 907                 up_read(&disk->lookup_sem);
 908         }
 909         return disk;
 910 }
 911 EXPORT_SYMBOL(get_gendisk);
 912 
 913 /**
 914  * bdget_disk - do bdget() by gendisk and partition number
 915  * @disk: gendisk of interest
 916  * @partno: partition number
 917  *
 918  * Find partition @partno from @disk, do bdget() on it.
 919  *
 920  * CONTEXT:
 921  * Don't care.
 922  *
 923  * RETURNS:
 924  * Resulting block_device on success, NULL on failure.
 925  */
 926 struct block_device *bdget_disk(struct gendisk *disk, int partno)
 927 {
 928         struct hd_struct *part;
 929         struct block_device *bdev = NULL;
 930 
 931         part = disk_get_part(disk, partno);
 932         if (part)
 933                 bdev = bdget(part_devt(part));
 934         disk_put_part(part);
 935 
 936         return bdev;
 937 }
 938 EXPORT_SYMBOL(bdget_disk);
 939 
 940 /*
 941  * print a full list of all partitions - intended for places where the root
 942  * filesystem can't be mounted and thus to give the victim some idea of what
 943  * went wrong
 944  */
 945 void __init printk_all_partitions(void)
 946 {
 947         struct class_dev_iter iter;
 948         struct device *dev;
 949 
 950         class_dev_iter_init(&iter, &block_class, NULL, &disk_type);
 951         while ((dev = class_dev_iter_next(&iter))) {
 952                 struct gendisk *disk = dev_to_disk(dev);
 953                 struct disk_part_iter piter;
 954                 struct hd_struct *part;
 955                 char name_buf[BDEVNAME_SIZE];
 956                 char devt_buf[BDEVT_SIZE];
 957 
 958                 /*
 959                  * Don't show empty devices or things that have been
 960                  * suppressed
 961                  */
 962                 if (get_capacity(disk) == 0 ||
 963                     (disk->flags & GENHD_FL_SUPPRESS_PARTITION_INFO))
 964                         continue;
 965 
 966                 /*
 967                  * Note, unlike /proc/partitions, I am showing the
 968                  * numbers in hex - the same format as the root=
 969                  * option takes.
 970                  */
 971                 disk_part_iter_init(&piter, disk, DISK_PITER_INCL_PART0);
 972                 while ((part = disk_part_iter_next(&piter))) {
 973                         bool is_part0 = part == &disk->part0;
 974 
 975                         printk("%s%s %10llu %s %s", is_part0 ? "" : "  ",
 976                                bdevt_str(part_devt(part), devt_buf),
 977                                (unsigned long long)part_nr_sects_read(part) >> 1
 978                                , disk_name(disk, part->partno, name_buf),
 979                                part->info ? part->info->uuid : "");
 980                         if (is_part0) {
 981                                 if (dev->parent && dev->parent->driver)
 982                                         printk(" driver: %s\n",
 983                                               dev->parent->driver->name);
 984                                 else
 985                                         printk(" (driver?)\n");
 986                         } else
 987                                 printk("\n");
 988                 }
 989                 disk_part_iter_exit(&piter);
 990         }
 991         class_dev_iter_exit(&iter);
 992 }
 993 
 994 #ifdef CONFIG_PROC_FS
 995 /* iterator */
 996 static void *disk_seqf_start(struct seq_file *seqf, loff_t *pos)
 997 {
 998         loff_t skip = *pos;
 999         struct class_dev_iter *iter;
1000         struct device *dev;
1001 
1002         iter = kmalloc(sizeof(*iter), GFP_KERNEL);
1003         if (!iter)
1004                 return ERR_PTR(-ENOMEM);
1005 
1006         seqf->private = iter;
1007         class_dev_iter_init(iter, &block_class, NULL, &disk_type);
1008         do {
1009                 dev = class_dev_iter_next(iter);
1010                 if (!dev)
1011                         return NULL;
1012         } while (skip--);
1013 
1014         return dev_to_disk(dev);
1015 }
1016 
1017 static void *disk_seqf_next(struct seq_file *seqf, void *v, loff_t *pos)
1018 {
1019         struct device *dev;
1020 
1021         (*pos)++;
1022         dev = class_dev_iter_next(seqf->private);
1023         if (dev)
1024                 return dev_to_disk(dev);
1025 
1026         return NULL;
1027 }
1028 
1029 static void disk_seqf_stop(struct seq_file *seqf, void *v)
1030 {
1031         struct class_dev_iter *iter = seqf->private;
1032 
1033         /* stop is called even after start failed :-( */
1034         if (iter) {
1035                 class_dev_iter_exit(iter);
1036                 kfree(iter);
1037                 seqf->private = NULL;
1038         }
1039 }
1040 
1041 static void *show_partition_start(struct seq_file *seqf, loff_t *pos)
1042 {
1043         void *p;
1044 
1045         p = disk_seqf_start(seqf, pos);
1046         if (!IS_ERR_OR_NULL(p) && !*pos)
1047                 seq_puts(seqf, "major minor  #blocks  name\n\n");
1048         return p;
1049 }
1050 
1051 static int show_partition(struct seq_file *seqf, void *v)
1052 {
1053         struct gendisk *sgp = v;
1054         struct disk_part_iter piter;
1055         struct hd_struct *part;
1056         char buf[BDEVNAME_SIZE];
1057 
1058         /* Don't show non-partitionable removeable devices or empty devices */
1059         if (!get_capacity(sgp) || (!disk_max_parts(sgp) &&
1060                                    (sgp->flags & GENHD_FL_REMOVABLE)))
1061                 return 0;
1062         if (sgp->flags & GENHD_FL_SUPPRESS_PARTITION_INFO)
1063                 return 0;
1064 
1065         /* show the full disk and all non-0 size partitions of it */
1066         disk_part_iter_init(&piter, sgp, DISK_PITER_INCL_PART0);
1067         while ((part = disk_part_iter_next(&piter)))
1068                 seq_printf(seqf, "%4d  %7d %10llu %s\n",
1069                            MAJOR(part_devt(part)), MINOR(part_devt(part)),
1070                            (unsigned long long)part_nr_sects_read(part) >> 1,
1071                            disk_name(sgp, part->partno, buf));
1072         disk_part_iter_exit(&piter);
1073 
1074         return 0;
1075 }
1076 
1077 static const struct seq_operations partitions_op = {
1078         .start  = show_partition_start,
1079         .next   = disk_seqf_next,
1080         .stop   = disk_seqf_stop,
1081         .show   = show_partition
1082 };
1083 #endif
1084 
1085 
1086 static struct kobject *base_probe(dev_t devt, int *partno, void *data)
1087 {
1088         if (request_module("block-major-%d-%d", MAJOR(devt), MINOR(devt)) > 0)
1089                 /* Make old-style 2.4 aliases work */
1090                 request_module("block-major-%d", MAJOR(devt));
1091         return NULL;
1092 }
1093 
1094 static int __init genhd_device_init(void)
1095 {
1096         int error;
1097 
1098         block_class.dev_kobj = sysfs_dev_block_kobj;
1099         error = class_register(&block_class);
1100         if (unlikely(error))
1101                 return error;
1102         bdev_map = kobj_map_init(base_probe, &block_class_lock);
1103         blk_dev_init();
1104 
1105         register_blkdev(BLOCK_EXT_MAJOR, "blkext");
1106 
1107         /* create top-level block dir */
1108         if (!sysfs_deprecated)
1109                 block_depr = kobject_create_and_add("block", NULL);
1110         return 0;
1111 }
1112 
1113 subsys_initcall(genhd_device_init);
1114 
1115 static ssize_t disk_range_show(struct device *dev,
1116                                struct device_attribute *attr, char *buf)
1117 {
1118         struct gendisk *disk = dev_to_disk(dev);
1119 
1120         return sprintf(buf, "%d\n", disk->minors);
1121 }
1122 
1123 static ssize_t disk_ext_range_show(struct device *dev,
1124                                    struct device_attribute *attr, char *buf)
1125 {
1126         struct gendisk *disk = dev_to_disk(dev);
1127 
1128         return sprintf(buf, "%d\n", disk_max_parts(disk));
1129 }
1130 
1131 static ssize_t disk_removable_show(struct device *dev,
1132                                    struct device_attribute *attr, char *buf)
1133 {
1134         struct gendisk *disk = dev_to_disk(dev);
1135 
1136         return sprintf(buf, "%d\n",
1137                        (disk->flags & GENHD_FL_REMOVABLE ? 1 : 0));
1138 }
1139 
1140 static ssize_t disk_hidden_show(struct device *dev,
1141                                    struct device_attribute *attr, char *buf)
1142 {
1143         struct gendisk *disk = dev_to_disk(dev);
1144 
1145         return sprintf(buf, "%d\n",
1146                        (disk->flags & GENHD_FL_HIDDEN ? 1 : 0));
1147 }
1148 
1149 static ssize_t disk_ro_show(struct device *dev,
1150                                    struct device_attribute *attr, char *buf)
1151 {
1152         struct gendisk *disk = dev_to_disk(dev);
1153 
1154         return sprintf(buf, "%d\n", get_disk_ro(disk) ? 1 : 0);
1155 }
1156 
1157 static ssize_t disk_capability_show(struct device *dev,
1158                                     struct device_attribute *attr, char *buf)
1159 {
1160         struct gendisk *disk = dev_to_disk(dev);
1161 
1162         return sprintf(buf, "%x\n", disk->flags);
1163 }
1164 
1165 static ssize_t disk_alignment_offset_show(struct device *dev,
1166                                           struct device_attribute *attr,
1167                                           char *buf)
1168 {
1169         struct gendisk *disk = dev_to_disk(dev);
1170 
1171         return sprintf(buf, "%d\n", queue_alignment_offset(disk->queue));
1172 }
1173 
1174 static ssize_t disk_discard_alignment_show(struct device *dev,
1175                                            struct device_attribute *attr,
1176                                            char *buf)
1177 {
1178         struct gendisk *disk = dev_to_disk(dev);
1179 
1180         return sprintf(buf, "%d\n", queue_discard_alignment(disk->queue));
1181 }
1182 
1183 static DEVICE_ATTR(range, 0444, disk_range_show, NULL);
1184 static DEVICE_ATTR(ext_range, 0444, disk_ext_range_show, NULL);
1185 static DEVICE_ATTR(removable, 0444, disk_removable_show, NULL);
1186 static DEVICE_ATTR(hidden, 0444, disk_hidden_show, NULL);
1187 static DEVICE_ATTR(ro, 0444, disk_ro_show, NULL);
1188 static DEVICE_ATTR(size, 0444, part_size_show, NULL);
1189 static DEVICE_ATTR(alignment_offset, 0444, disk_alignment_offset_show, NULL);
1190 static DEVICE_ATTR(discard_alignment, 0444, disk_discard_alignment_show, NULL);
1191 static DEVICE_ATTR(capability, 0444, disk_capability_show, NULL);
1192 static DEVICE_ATTR(stat, 0444, part_stat_show, NULL);
1193 static DEVICE_ATTR(inflight, 0444, part_inflight_show, NULL);
1194 static DEVICE_ATTR(badblocks, 0644, disk_badblocks_show, disk_badblocks_store);
1195 #ifdef CONFIG_FAIL_MAKE_REQUEST
1196 static struct device_attribute dev_attr_fail =
1197         __ATTR(make-it-fail, 0644, part_fail_show, part_fail_store);
1198 #endif
1199 #ifdef CONFIG_FAIL_IO_TIMEOUT
1200 static struct device_attribute dev_attr_fail_timeout =
1201         __ATTR(io-timeout-fail, 0644, part_timeout_show, part_timeout_store);
1202 #endif
1203 
1204 static struct attribute *disk_attrs[] = {
1205         &dev_attr_range.attr,
1206         &dev_attr_ext_range.attr,
1207         &dev_attr_removable.attr,
1208         &dev_attr_hidden.attr,
1209         &dev_attr_ro.attr,
1210         &dev_attr_size.attr,
1211         &dev_attr_alignment_offset.attr,
1212         &dev_attr_discard_alignment.attr,
1213         &dev_attr_capability.attr,
1214         &dev_attr_stat.attr,
1215         &dev_attr_inflight.attr,
1216         &dev_attr_badblocks.attr,
1217 #ifdef CONFIG_FAIL_MAKE_REQUEST
1218         &dev_attr_fail.attr,
1219 #endif
1220 #ifdef CONFIG_FAIL_IO_TIMEOUT
1221         &dev_attr_fail_timeout.attr,
1222 #endif
1223         NULL
1224 };
1225 
1226 static umode_t disk_visible(struct kobject *kobj, struct attribute *a, int n)
1227 {
1228         struct device *dev = container_of(kobj, typeof(*dev), kobj);
1229         struct gendisk *disk = dev_to_disk(dev);
1230 
1231         if (a == &dev_attr_badblocks.attr && !disk->bb)
1232                 return 0;
1233         return a->mode;
1234 }
1235 
1236 static struct attribute_group disk_attr_group = {
1237         .attrs = disk_attrs,
1238         .is_visible = disk_visible,
1239 };
1240 
1241 static const struct attribute_group *disk_attr_groups[] = {
1242         &disk_attr_group,
1243         NULL
1244 };
1245 
1246 /**
1247  * disk_replace_part_tbl - replace disk->part_tbl in RCU-safe way
1248  * @disk: disk to replace part_tbl for
1249  * @new_ptbl: new part_tbl to install
1250  *
1251  * Replace disk->part_tbl with @new_ptbl in RCU-safe way.  The
1252  * original ptbl is freed using RCU callback.
1253  *
1254  * LOCKING:
1255  * Matching bd_mutex locked or the caller is the only user of @disk.
1256  */
1257 static void disk_replace_part_tbl(struct gendisk *disk,
1258                                   struct disk_part_tbl *new_ptbl)
1259 {
1260         struct disk_part_tbl *old_ptbl =
1261                 rcu_dereference_protected(disk->part_tbl, 1);
1262 
1263         rcu_assign_pointer(disk->part_tbl, new_ptbl);
1264 
1265         if (old_ptbl) {
1266                 rcu_assign_pointer(old_ptbl->last_lookup, NULL);
1267                 kfree_rcu(old_ptbl, rcu_head);
1268         }
1269 }
1270 
1271 /**
1272  * disk_expand_part_tbl - expand disk->part_tbl
1273  * @disk: disk to expand part_tbl for
1274  * @partno: expand such that this partno can fit in
1275  *
1276  * Expand disk->part_tbl such that @partno can fit in.  disk->part_tbl
1277  * uses RCU to allow unlocked dereferencing for stats and other stuff.
1278  *
1279  * LOCKING:
1280  * Matching bd_mutex locked or the caller is the only user of @disk.
1281  * Might sleep.
1282  *
1283  * RETURNS:
1284  * 0 on success, -errno on failure.
1285  */
1286 int disk_expand_part_tbl(struct gendisk *disk, int partno)
1287 {
1288         struct disk_part_tbl *old_ptbl =
1289                 rcu_dereference_protected(disk->part_tbl, 1);
1290         struct disk_part_tbl *new_ptbl;
1291         int len = old_ptbl ? old_ptbl->len : 0;
1292         int i, target;
1293 
1294         /*
1295          * check for int overflow, since we can get here from blkpg_ioctl()
1296          * with a user passed 'partno'.
1297          */
1298         target = partno + 1;
1299         if (target < 0)
1300                 return -EINVAL;
1301 
1302         /* disk_max_parts() is zero during initialization, ignore if so */
1303         if (disk_max_parts(disk) && target > disk_max_parts(disk))
1304                 return -EINVAL;
1305 
1306         if (target <= len)
1307                 return 0;
1308 
1309         new_ptbl = kzalloc_node(struct_size(new_ptbl, part, target), GFP_KERNEL,
1310                                 disk->node_id);
1311         if (!new_ptbl)
1312                 return -ENOMEM;
1313 
1314         new_ptbl->len = target;
1315 
1316         for (i = 0; i < len; i++)
1317                 rcu_assign_pointer(new_ptbl->part[i], old_ptbl->part[i]);
1318 
1319         disk_replace_part_tbl(disk, new_ptbl);
1320         return 0;
1321 }
1322 
1323 static void disk_release(struct device *dev)
1324 {
1325         struct gendisk *disk = dev_to_disk(dev);
1326 
1327         blk_free_devt(dev->devt);
1328         disk_release_events(disk);
1329         kfree(disk->random);
1330         disk_replace_part_tbl(disk, NULL);
1331         hd_free_part(&disk->part0);
1332         if (disk->queue)
1333                 blk_put_queue(disk->queue);
1334         kfree(disk);
1335 }
1336 struct class block_class = {
1337         .name           = "block",
1338 };
1339 
1340 static char *block_devnode(struct device *dev, umode_t *mode,
1341                            kuid_t *uid, kgid_t *gid)
1342 {
1343         struct gendisk *disk = dev_to_disk(dev);
1344 
1345         if (disk->devnode)
1346                 return disk->devnode(disk, mode);
1347         return NULL;
1348 }
1349 
1350 static const struct device_type disk_type = {
1351         .name           = "disk",
1352         .groups         = disk_attr_groups,
1353         .release        = disk_release,
1354         .devnode        = block_devnode,
1355 };
1356 
1357 #ifdef CONFIG_PROC_FS
1358 /*
1359  * aggregate disk stat collector.  Uses the same stats that the sysfs
1360  * entries do, above, but makes them available through one seq_file.
1361  *
1362  * The output looks suspiciously like /proc/partitions with a bunch of
1363  * extra fields.
1364  */
1365 static int diskstats_show(struct seq_file *seqf, void *v)
1366 {
1367         struct gendisk *gp = v;
1368         struct disk_part_iter piter;
1369         struct hd_struct *hd;
1370         char buf[BDEVNAME_SIZE];
1371         unsigned int inflight;
1372 
1373         /*
1374         if (&disk_to_dev(gp)->kobj.entry == block_class.devices.next)
1375                 seq_puts(seqf,  "major minor name"
1376                                 "     rio rmerge rsect ruse wio wmerge "
1377                                 "wsect wuse running use aveq"
1378                                 "\n\n");
1379         */
1380 
1381         disk_part_iter_init(&piter, gp, DISK_PITER_INCL_EMPTY_PART0);
1382         while ((hd = disk_part_iter_next(&piter))) {
1383                 inflight = part_in_flight(gp->queue, hd);
1384                 seq_printf(seqf, "%4d %7d %s "
1385                            "%lu %lu %lu %u "
1386                            "%lu %lu %lu %u "
1387                            "%u %u %u "
1388                            "%lu %lu %lu %u\n",
1389                            MAJOR(part_devt(hd)), MINOR(part_devt(hd)),
1390                            disk_name(gp, hd->partno, buf),
1391                            part_stat_read(hd, ios[STAT_READ]),
1392                            part_stat_read(hd, merges[STAT_READ]),
1393                            part_stat_read(hd, sectors[STAT_READ]),
1394                            (unsigned int)part_stat_read_msecs(hd, STAT_READ),
1395                            part_stat_read(hd, ios[STAT_WRITE]),
1396                            part_stat_read(hd, merges[STAT_WRITE]),
1397                            part_stat_read(hd, sectors[STAT_WRITE]),
1398                            (unsigned int)part_stat_read_msecs(hd, STAT_WRITE),
1399                            inflight,
1400                            jiffies_to_msecs(part_stat_read(hd, io_ticks)),
1401                            jiffies_to_msecs(part_stat_read(hd, time_in_queue)),
1402                            part_stat_read(hd, ios[STAT_DISCARD]),
1403                            part_stat_read(hd, merges[STAT_DISCARD]),
1404                            part_stat_read(hd, sectors[STAT_DISCARD]),
1405                            (unsigned int)part_stat_read_msecs(hd, STAT_DISCARD)
1406                         );
1407         }
1408         disk_part_iter_exit(&piter);
1409 
1410         return 0;
1411 }
1412 
1413 static const struct seq_operations diskstats_op = {
1414         .start  = disk_seqf_start,
1415         .next   = disk_seqf_next,
1416         .stop   = disk_seqf_stop,
1417         .show   = diskstats_show
1418 };
1419 
1420 static int __init proc_genhd_init(void)
1421 {
1422         proc_create_seq("diskstats", 0, NULL, &diskstats_op);
1423         proc_create_seq("partitions", 0, NULL, &partitions_op);
1424         return 0;
1425 }
1426 module_init(proc_genhd_init);
1427 #endif /* CONFIG_PROC_FS */
1428 
1429 dev_t blk_lookup_devt(const char *name, int partno)
1430 {
1431         dev_t devt = MKDEV(0, 0);
1432         struct class_dev_iter iter;
1433         struct device *dev;
1434 
1435         class_dev_iter_init(&iter, &block_class, NULL, &disk_type);
1436         while ((dev = class_dev_iter_next(&iter))) {
1437                 struct gendisk *disk = dev_to_disk(dev);
1438                 struct hd_struct *part;
1439 
1440                 if (strcmp(dev_name(dev), name))
1441                         continue;
1442 
1443                 if (partno < disk->minors) {
1444                         /* We need to return the right devno, even
1445                          * if the partition doesn't exist yet.
1446                          */
1447                         devt = MKDEV(MAJOR(dev->devt),
1448                                      MINOR(dev->devt) + partno);
1449                         break;
1450                 }
1451                 part = disk_get_part(disk, partno);
1452                 if (part) {
1453                         devt = part_devt(part);
1454                         disk_put_part(part);
1455                         break;
1456                 }
1457                 disk_put_part(part);
1458         }
1459         class_dev_iter_exit(&iter);
1460         return devt;
1461 }
1462 EXPORT_SYMBOL(blk_lookup_devt);
1463 
1464 struct gendisk *__alloc_disk_node(int minors, int node_id)
1465 {
1466         struct gendisk *disk;
1467         struct disk_part_tbl *ptbl;
1468 
1469         if (minors > DISK_MAX_PARTS) {
1470                 printk(KERN_ERR
1471                         "block: can't allocate more than %d partitions\n",
1472                         DISK_MAX_PARTS);
1473                 minors = DISK_MAX_PARTS;
1474         }
1475 
1476         disk = kzalloc_node(sizeof(struct gendisk), GFP_KERNEL, node_id);
1477         if (disk) {
1478                 if (!init_part_stats(&disk->part0)) {
1479                         kfree(disk);
1480                         return NULL;
1481                 }
1482                 init_rwsem(&disk->lookup_sem);
1483                 disk->node_id = node_id;
1484                 if (disk_expand_part_tbl(disk, 0)) {
1485                         free_part_stats(&disk->part0);
1486                         kfree(disk);
1487                         return NULL;
1488                 }
1489                 ptbl = rcu_dereference_protected(disk->part_tbl, 1);
1490                 rcu_assign_pointer(ptbl->part[0], &disk->part0);
1491 
1492                 /*
1493                  * set_capacity() and get_capacity() currently don't use
1494                  * seqcounter to read/update the part0->nr_sects. Still init
1495                  * the counter as we can read the sectors in IO submission
1496                  * patch using seqence counters.
1497                  *
1498                  * TODO: Ideally set_capacity() and get_capacity() should be
1499                  * converted to make use of bd_mutex and sequence counters.
1500                  */
1501                 seqcount_init(&disk->part0.nr_sects_seq);
1502                 if (hd_ref_init(&disk->part0)) {
1503                         hd_free_part(&disk->part0);
1504                         kfree(disk);
1505                         return NULL;
1506                 }
1507 
1508                 disk->minors = minors;
1509                 rand_initialize_disk(disk);
1510                 disk_to_dev(disk)->class = &block_class;
1511                 disk_to_dev(disk)->type = &disk_type;
1512                 device_initialize(disk_to_dev(disk));
1513         }
1514         return disk;
1515 }
1516 EXPORT_SYMBOL(__alloc_disk_node);
1517 
1518 struct kobject *get_disk_and_module(struct gendisk *disk)
1519 {
1520         struct module *owner;
1521         struct kobject *kobj;
1522 
1523         if (!disk->fops)
1524                 return NULL;
1525         owner = disk->fops->owner;
1526         if (owner && !try_module_get(owner))
1527                 return NULL;
1528         kobj = kobject_get_unless_zero(&disk_to_dev(disk)->kobj);
1529         if (kobj == NULL) {
1530                 module_put(owner);
1531                 return NULL;
1532         }
1533         return kobj;
1534 
1535 }
1536 EXPORT_SYMBOL(get_disk_and_module);
1537 
1538 void put_disk(struct gendisk *disk)
1539 {
1540         if (disk)
1541                 kobject_put(&disk_to_dev(disk)->kobj);
1542 }
1543 EXPORT_SYMBOL(put_disk);
1544 
1545 /*
1546  * This is a counterpart of get_disk_and_module() and thus also of
1547  * get_gendisk().
1548  */
1549 void put_disk_and_module(struct gendisk *disk)
1550 {
1551         if (disk) {
1552                 struct module *owner = disk->fops->owner;
1553 
1554                 put_disk(disk);
1555                 module_put(owner);
1556         }
1557 }
1558 EXPORT_SYMBOL(put_disk_and_module);
1559 
1560 static void set_disk_ro_uevent(struct gendisk *gd, int ro)
1561 {
1562         char event[] = "DISK_RO=1";
1563         char *envp[] = { event, NULL };
1564 
1565         if (!ro)
1566                 event[8] = '0';
1567         kobject_uevent_env(&disk_to_dev(gd)->kobj, KOBJ_CHANGE, envp);
1568 }
1569 
1570 void set_device_ro(struct block_device *bdev, int flag)
1571 {
1572         bdev->bd_part->policy = flag;
1573 }
1574 
1575 EXPORT_SYMBOL(set_device_ro);
1576 
1577 void set_disk_ro(struct gendisk *disk, int flag)
1578 {
1579         struct disk_part_iter piter;
1580         struct hd_struct *part;
1581 
1582         if (disk->part0.policy != flag) {
1583                 set_disk_ro_uevent(disk, flag);
1584                 disk->part0.policy = flag;
1585         }
1586 
1587         disk_part_iter_init(&piter, disk, DISK_PITER_INCL_EMPTY);
1588         while ((part = disk_part_iter_next(&piter)))
1589                 part->policy = flag;
1590         disk_part_iter_exit(&piter);
1591 }
1592 
1593 EXPORT_SYMBOL(set_disk_ro);
1594 
1595 int bdev_read_only(struct block_device *bdev)
1596 {
1597         if (!bdev)
1598                 return 0;
1599         return bdev->bd_part->policy;
1600 }
1601 
1602 EXPORT_SYMBOL(bdev_read_only);
1603 
1604 int invalidate_partition(struct gendisk *disk, int partno)
1605 {
1606         int res = 0;
1607         struct block_device *bdev = bdget_disk(disk, partno);
1608         if (bdev) {
1609                 fsync_bdev(bdev);
1610                 res = __invalidate_device(bdev, true);
1611                 bdput(bdev);
1612         }
1613         return res;
1614 }
1615 
1616 EXPORT_SYMBOL(invalidate_partition);
1617 
1618 /*
1619  * Disk events - monitor disk events like media change and eject request.
1620  */
1621 struct disk_events {
1622         struct list_head        node;           /* all disk_event's */
1623         struct gendisk          *disk;          /* the associated disk */
1624         spinlock_t              lock;
1625 
1626         struct mutex            block_mutex;    /* protects blocking */
1627         int                     block;          /* event blocking depth */
1628         unsigned int            pending;        /* events already sent out */
1629         unsigned int            clearing;       /* events being cleared */
1630 
1631         long                    poll_msecs;     /* interval, -1 for default */
1632         struct delayed_work     dwork;
1633 };
1634 
1635 static const char *disk_events_strs[] = {
1636         [ilog2(DISK_EVENT_MEDIA_CHANGE)]        = "media_change",
1637         [ilog2(DISK_EVENT_EJECT_REQUEST)]       = "eject_request",
1638 };
1639 
1640 static char *disk_uevents[] = {
1641         [ilog2(DISK_EVENT_MEDIA_CHANGE)]        = "DISK_MEDIA_CHANGE=1",
1642         [ilog2(DISK_EVENT_EJECT_REQUEST)]       = "DISK_EJECT_REQUEST=1",
1643 };
1644 
1645 /* list of all disk_events */
1646 static DEFINE_MUTEX(disk_events_mutex);
1647 static LIST_HEAD(disk_events);
1648 
1649 /* disable in-kernel polling by default */
1650 static unsigned long disk_events_dfl_poll_msecs;
1651 
1652 static unsigned long disk_events_poll_jiffies(struct gendisk *disk)
1653 {
1654         struct disk_events *ev = disk->ev;
1655         long intv_msecs = 0;
1656 
1657         /*
1658          * If device-specific poll interval is set, always use it.  If
1659          * the default is being used, poll if the POLL flag is set.
1660          */
1661         if (ev->poll_msecs >= 0)
1662                 intv_msecs = ev->poll_msecs;
1663         else if (disk->event_flags & DISK_EVENT_FLAG_POLL)
1664                 intv_msecs = disk_events_dfl_poll_msecs;
1665 
1666         return msecs_to_jiffies(intv_msecs);
1667 }
1668 
1669 /**
1670  * disk_block_events - block and flush disk event checking
1671  * @disk: disk to block events for
1672  *
1673  * On return from this function, it is guaranteed that event checking
1674  * isn't in progress and won't happen until unblocked by
1675  * disk_unblock_events().  Events blocking is counted and the actual
1676  * unblocking happens after the matching number of unblocks are done.
1677  *
1678  * Note that this intentionally does not block event checking from
1679  * disk_clear_events().
1680  *
1681  * CONTEXT:
1682  * Might sleep.
1683  */
1684 void disk_block_events(struct gendisk *disk)
1685 {
1686         struct disk_events *ev = disk->ev;
1687         unsigned long flags;
1688         bool cancel;
1689 
1690         if (!ev)
1691                 return;
1692 
1693         /*
1694          * Outer mutex ensures that the first blocker completes canceling
1695          * the event work before further blockers are allowed to finish.
1696          */
1697         mutex_lock(&ev->block_mutex);
1698 
1699         spin_lock_irqsave(&ev->lock, flags);
1700         cancel = !ev->block++;
1701         spin_unlock_irqrestore(&ev->lock, flags);
1702 
1703         if (cancel)
1704                 cancel_delayed_work_sync(&disk->ev->dwork);
1705 
1706         mutex_unlock(&ev->block_mutex);
1707 }
1708 
1709 static void __disk_unblock_events(struct gendisk *disk, bool check_now)
1710 {
1711         struct disk_events *ev = disk->ev;
1712         unsigned long intv;
1713         unsigned long flags;
1714 
1715         spin_lock_irqsave(&ev->lock, flags);
1716 
1717         if (WARN_ON_ONCE(ev->block <= 0))
1718                 goto out_unlock;
1719 
1720         if (--ev->block)
1721                 goto out_unlock;
1722 
1723         intv = disk_events_poll_jiffies(disk);
1724         if (check_now)
1725                 queue_delayed_work(system_freezable_power_efficient_wq,
1726                                 &ev->dwork, 0);
1727         else if (intv)
1728                 queue_delayed_work(system_freezable_power_efficient_wq,
1729                                 &ev->dwork, intv);
1730 out_unlock:
1731         spin_unlock_irqrestore(&ev->lock, flags);
1732 }
1733 
1734 /**
1735  * disk_unblock_events - unblock disk event checking
1736  * @disk: disk to unblock events for
1737  *
1738  * Undo disk_block_events().  When the block count reaches zero, it
1739  * starts events polling if configured.
1740  *
1741  * CONTEXT:
1742  * Don't care.  Safe to call from irq context.
1743  */
1744 void disk_unblock_events(struct gendisk *disk)
1745 {
1746         if (disk->ev)
1747                 __disk_unblock_events(disk, false);
1748 }
1749 
1750 /**
1751  * disk_flush_events - schedule immediate event checking and flushing
1752  * @disk: disk to check and flush events for
1753  * @mask: events to flush
1754  *
1755  * Schedule immediate event checking on @disk if not blocked.  Events in
1756  * @mask are scheduled to be cleared from the driver.  Note that this
1757  * doesn't clear the events from @disk->ev.
1758  *
1759  * CONTEXT:
1760  * If @mask is non-zero must be called with bdev->bd_mutex held.
1761  */
1762 void disk_flush_events(struct gendisk *disk, unsigned int mask)
1763 {
1764         struct disk_events *ev = disk->ev;
1765 
1766         if (!ev)
1767                 return;
1768 
1769         spin_lock_irq(&ev->lock);
1770         ev->clearing |= mask;
1771         if (!ev->block)
1772                 mod_delayed_work(system_freezable_power_efficient_wq,
1773                                 &ev->dwork, 0);
1774         spin_unlock_irq(&ev->lock);
1775 }
1776 
1777 /**
1778  * disk_clear_events - synchronously check, clear and return pending events
1779  * @disk: disk to fetch and clear events from
1780  * @mask: mask of events to be fetched and cleared
1781  *
1782  * Disk events are synchronously checked and pending events in @mask
1783  * are cleared and returned.  This ignores the block count.
1784  *
1785  * CONTEXT:
1786  * Might sleep.
1787  */
1788 unsigned int disk_clear_events(struct gendisk *disk, unsigned int mask)
1789 {
1790         const struct block_device_operations *bdops = disk->fops;
1791         struct disk_events *ev = disk->ev;
1792         unsigned int pending;
1793         unsigned int clearing = mask;
1794 
1795         if (!ev) {
1796                 /* for drivers still using the old ->media_changed method */
1797                 if ((mask & DISK_EVENT_MEDIA_CHANGE) &&
1798                     bdops->media_changed && bdops->media_changed(disk))
1799                         return DISK_EVENT_MEDIA_CHANGE;
1800                 return 0;
1801         }
1802 
1803         disk_block_events(disk);
1804 
1805         /*
1806          * store the union of mask and ev->clearing on the stack so that the
1807          * race with disk_flush_events does not cause ambiguity (ev->clearing
1808          * can still be modified even if events are blocked).
1809          */
1810         spin_lock_irq(&ev->lock);
1811         clearing |= ev->clearing;
1812         ev->clearing = 0;
1813         spin_unlock_irq(&ev->lock);
1814 
1815         disk_check_events(ev, &clearing);
1816         /*
1817          * if ev->clearing is not 0, the disk_flush_events got called in the
1818          * middle of this function, so we want to run the workfn without delay.
1819          */
1820         __disk_unblock_events(disk, ev->clearing ? true : false);
1821 
1822         /* then, fetch and clear pending events */
1823         spin_lock_irq(&ev->lock);
1824         pending = ev->pending & mask;
1825         ev->pending &= ~mask;
1826         spin_unlock_irq(&ev->lock);
1827         WARN_ON_ONCE(clearing & mask);
1828 
1829         return pending;
1830 }
1831 
1832 /*
1833  * Separate this part out so that a different pointer for clearing_ptr can be
1834  * passed in for disk_clear_events.
1835  */
1836 static void disk_events_workfn(struct work_struct *work)
1837 {
1838         struct delayed_work *dwork = to_delayed_work(work);
1839         struct disk_events *ev = container_of(dwork, struct disk_events, dwork);
1840 
1841         disk_check_events(ev, &ev->clearing);
1842 }
1843 
1844 static void disk_check_events(struct disk_events *ev,
1845                               unsigned int *clearing_ptr)
1846 {
1847         struct gendisk *disk = ev->disk;
1848         char *envp[ARRAY_SIZE(disk_uevents) + 1] = { };
1849         unsigned int clearing = *clearing_ptr;
1850         unsigned int events;
1851         unsigned long intv;
1852         int nr_events = 0, i;
1853 
1854         /* check events */
1855         events = disk->fops->check_events(disk, clearing);
1856 
1857         /* accumulate pending events and schedule next poll if necessary */
1858         spin_lock_irq(&ev->lock);
1859 
1860         events &= ~ev->pending;
1861         ev->pending |= events;
1862         *clearing_ptr &= ~clearing;
1863 
1864         intv = disk_events_poll_jiffies(disk);
1865         if (!ev->block && intv)
1866                 queue_delayed_work(system_freezable_power_efficient_wq,
1867                                 &ev->dwork, intv);
1868 
1869         spin_unlock_irq(&ev->lock);
1870 
1871         /*
1872          * Tell userland about new events.  Only the events listed in
1873          * @disk->events are reported, and only if DISK_EVENT_FLAG_UEVENT
1874          * is set. Otherwise, events are processed internally but never
1875          * get reported to userland.
1876          */
1877         for (i = 0; i < ARRAY_SIZE(disk_uevents); i++)
1878                 if ((events & disk->events & (1 << i)) &&
1879                     (disk->event_flags & DISK_EVENT_FLAG_UEVENT))
1880                         envp[nr_events++] = disk_uevents[i];
1881 
1882         if (nr_events)
1883                 kobject_uevent_env(&disk_to_dev(disk)->kobj, KOBJ_CHANGE, envp);
1884 }
1885 
1886 /*
1887  * A disk events enabled device has the following sysfs nodes under
1888  * its /sys/block/X/ directory.
1889  *
1890  * events               : list of all supported events
1891  * events_async         : list of events which can be detected w/o polling
1892  *                        (always empty, only for backwards compatibility)
1893  * events_poll_msecs    : polling interval, 0: disable, -1: system default
1894  */
1895 static ssize_t __disk_events_show(unsigned int events, char *buf)
1896 {
1897         const char *delim = "";
1898         ssize_t pos = 0;
1899         int i;
1900 
1901         for (i = 0; i < ARRAY_SIZE(disk_events_strs); i++)
1902                 if (events & (1 << i)) {
1903                         pos += sprintf(buf + pos, "%s%s",
1904                                        delim, disk_events_strs[i]);
1905                         delim = " ";
1906                 }
1907         if (pos)
1908                 pos += sprintf(buf + pos, "\n");
1909         return pos;
1910 }
1911 
1912 static ssize_t disk_events_show(struct device *dev,
1913                                 struct device_attribute *attr, char *buf)
1914 {
1915         struct gendisk *disk = dev_to_disk(dev);
1916 
1917         if (!(disk->event_flags & DISK_EVENT_FLAG_UEVENT))
1918                 return 0;
1919 
1920         return __disk_events_show(disk->events, buf);
1921 }
1922 
1923 static ssize_t disk_events_async_show(struct device *dev,
1924                                       struct device_attribute *attr, char *buf)
1925 {
1926         return 0;
1927 }
1928 
1929 static ssize_t disk_events_poll_msecs_show(struct device *dev,
1930                                            struct device_attribute *attr,
1931                                            char *buf)
1932 {
1933         struct gendisk *disk = dev_to_disk(dev);
1934 
1935         if (!disk->ev)
1936                 return sprintf(buf, "-1\n");
1937 
1938         return sprintf(buf, "%ld\n", disk->ev->poll_msecs);
1939 }
1940 
1941 static ssize_t disk_events_poll_msecs_store(struct device *dev,
1942                                             struct device_attribute *attr,
1943                                             const char *buf, size_t count)
1944 {
1945         struct gendisk *disk = dev_to_disk(dev);
1946         long intv;
1947 
1948         if (!count || !sscanf(buf, "%ld", &intv))
1949                 return -EINVAL;
1950 
1951         if (intv < 0 && intv != -1)
1952                 return -EINVAL;
1953 
1954         if (!disk->ev)
1955                 return -ENODEV;
1956 
1957         disk_block_events(disk);
1958         disk->ev->poll_msecs = intv;
1959         __disk_unblock_events(disk, true);
1960 
1961         return count;
1962 }
1963 
1964 static const DEVICE_ATTR(events, 0444, disk_events_show, NULL);
1965 static const DEVICE_ATTR(events_async, 0444, disk_events_async_show, NULL);
1966 static const DEVICE_ATTR(events_poll_msecs, 0644,
1967                          disk_events_poll_msecs_show,
1968                          disk_events_poll_msecs_store);
1969 
1970 static const struct attribute *disk_events_attrs[] = {
1971         &dev_attr_events.attr,
1972         &dev_attr_events_async.attr,
1973         &dev_attr_events_poll_msecs.attr,
1974         NULL,
1975 };
1976 
1977 /*
1978  * The default polling interval can be specified by the kernel
1979  * parameter block.events_dfl_poll_msecs which defaults to 0
1980  * (disable).  This can also be modified runtime by writing to
1981  * /sys/module/block/parameters/events_dfl_poll_msecs.
1982  */
1983 static int disk_events_set_dfl_poll_msecs(const char *val,
1984                                           const struct kernel_param *kp)
1985 {
1986         struct disk_events *ev;
1987         int ret;
1988 
1989         ret = param_set_ulong(val, kp);
1990         if (ret < 0)
1991                 return ret;
1992 
1993         mutex_lock(&disk_events_mutex);
1994 
1995         list_for_each_entry(ev, &disk_events, node)
1996                 disk_flush_events(ev->disk, 0);
1997 
1998         mutex_unlock(&disk_events_mutex);
1999 
2000         return 0;
2001 }
2002 
2003 static const struct kernel_param_ops disk_events_dfl_poll_msecs_param_ops = {
2004         .set    = disk_events_set_dfl_poll_msecs,
2005         .get    = param_get_ulong,
2006 };
2007 
2008 #undef MODULE_PARAM_PREFIX
2009 #define MODULE_PARAM_PREFIX     "block."
2010 
2011 module_param_cb(events_dfl_poll_msecs, &disk_events_dfl_poll_msecs_param_ops,
2012                 &disk_events_dfl_poll_msecs, 0644);
2013 
2014 /*
2015  * disk_{alloc|add|del|release}_events - initialize and destroy disk_events.
2016  */
2017 static void disk_alloc_events(struct gendisk *disk)
2018 {
2019         struct disk_events *ev;
2020 
2021         if (!disk->fops->check_events || !disk->events)
2022                 return;
2023 
2024         ev = kzalloc(sizeof(*ev), GFP_KERNEL);
2025         if (!ev) {
2026                 pr_warn("%s: failed to initialize events\n", disk->disk_name);
2027                 return;
2028         }
2029 
2030         INIT_LIST_HEAD(&ev->node);
2031         ev->disk = disk;
2032         spin_lock_init(&ev->lock);
2033         mutex_init(&ev->block_mutex);
2034         ev->block = 1;
2035         ev->poll_msecs = -1;
2036         INIT_DELAYED_WORK(&ev->dwork, disk_events_workfn);
2037 
2038         disk->ev = ev;
2039 }
2040 
2041 static void disk_add_events(struct gendisk *disk)
2042 {
2043         /* FIXME: error handling */
2044         if (sysfs_create_files(&disk_to_dev(disk)->kobj, disk_events_attrs) < 0)
2045                 pr_warn("%s: failed to create sysfs files for events\n",
2046                         disk->disk_name);
2047 
2048         if (!disk->ev)
2049                 return;
2050 
2051         mutex_lock(&disk_events_mutex);
2052         list_add_tail(&disk->ev->node, &disk_events);
2053         mutex_unlock(&disk_events_mutex);
2054 
2055         /*
2056          * Block count is initialized to 1 and the following initial
2057          * unblock kicks it into action.
2058          */
2059         __disk_unblock_events(disk, true);
2060 }
2061 
2062 static void disk_del_events(struct gendisk *disk)
2063 {
2064         if (disk->ev) {
2065                 disk_block_events(disk);
2066 
2067                 mutex_lock(&disk_events_mutex);
2068                 list_del_init(&disk->ev->node);
2069                 mutex_unlock(&disk_events_mutex);
2070         }
2071 
2072         sysfs_remove_files(&disk_to_dev(disk)->kobj, disk_events_attrs);
2073 }
2074 
2075 static void disk_release_events(struct gendisk *disk)
2076 {
2077         /* the block count should be 1 from disk_del_events() */
2078         WARN_ON_ONCE(disk->ev && disk->ev->block != 1);
2079         kfree(disk->ev);
2080 }
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root/block/genhd.c

DEFINITIONS
