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1// SPDX-License-Identifier: GPL-2.02/*3 * gendisk handling4 *5 * Portions Copyright (C) 2020 Christoph Hellwig6 */7 8#include <linux/module.h>9#include <linux/ctype.h>10#include <linux/fs.h>11#include <linux/kdev_t.h>12#include <linux/kernel.h>13#include <linux/blkdev.h>14#include <linux/backing-dev.h>15#include <linux/init.h>16#include <linux/spinlock.h>17#include <linux/proc_fs.h>18#include <linux/seq_file.h>19#include <linux/slab.h>20#include <linux/kmod.h>21#include <linux/major.h>22#include <linux/mutex.h>23#include <linux/idr.h>24#include <linux/log2.h>25#include <linux/pm_runtime.h>26#include <linux/badblocks.h>27#include <linux/part_stat.h>28#include <linux/blktrace_api.h>29 30#include "blk-throttle.h"31#include "blk.h"32#include "blk-mq-sched.h"33#include "blk-rq-qos.h"34#include "blk-cgroup.h"35 36static struct kobject *block_depr;37 38/*39 * Unique, monotonically increasing sequential number associated with block40 * devices instances (i.e. incremented each time a device is attached).41 * Associating uevents with block devices in userspace is difficult and racy:42 * the uevent netlink socket is lossy, and on slow and overloaded systems has43 * a very high latency.44 * Block devices do not have exclusive owners in userspace, any process can set45 * one up (e.g. loop devices). Moreover, device names can be reused (e.g. loop046 * can be reused again and again).47 * A userspace process setting up a block device and watching for its events48 * cannot thus reliably tell whether an event relates to the device it just set49 * up or another earlier instance with the same name.50 * This sequential number allows userspace processes to solve this problem, and51 * uniquely associate an uevent to the lifetime to a device.52 */53static atomic64_t diskseq;54 55/* for extended dynamic devt allocation, currently only one major is used */56#define NR_EXT_DEVT (1 << MINORBITS)57static DEFINE_IDA(ext_devt_ida);58 59void set_capacity(struct gendisk *disk, sector_t sectors)60{61 bdev_set_nr_sectors(disk->part0, sectors);62}63EXPORT_SYMBOL(set_capacity);64 65/*66 * Set disk capacity and notify if the size is not currently zero and will not67 * be set to zero. Returns true if a uevent was sent, otherwise false.68 */69bool set_capacity_and_notify(struct gendisk *disk, sector_t size)70{71 sector_t capacity = get_capacity(disk);72 char *envp[] = { "RESIZE=1", NULL };73 74 set_capacity(disk, size);75 76 /*77 * Only print a message and send a uevent if the gendisk is user visible78 * and alive. This avoids spamming the log and udev when setting the79 * initial capacity during probing.80 */81 if (size == capacity ||82 !disk_live(disk) ||83 (disk->flags & GENHD_FL_HIDDEN))84 return false;85 86 pr_info("%s: detected capacity change from %lld to %lld\n",87 disk->disk_name, capacity, size);88 89 /*90 * Historically we did not send a uevent for changes to/from an empty91 * device.92 */93 if (!capacity || !size)94 return false;95 kobject_uevent_env(&disk_to_dev(disk)->kobj, KOBJ_CHANGE, envp);96 return true;97}98EXPORT_SYMBOL_GPL(set_capacity_and_notify);99 100static void part_stat_read_all(struct block_device *part,101 struct disk_stats *stat)102{103 int cpu;104 105 memset(stat, 0, sizeof(struct disk_stats));106 for_each_possible_cpu(cpu) {107 struct disk_stats *ptr = per_cpu_ptr(part->bd_stats, cpu);108 int group;109 110 for (group = 0; group < NR_STAT_GROUPS; group++) {111 stat->nsecs[group] += ptr->nsecs[group];112 stat->sectors[group] += ptr->sectors[group];113 stat->ios[group] += ptr->ios[group];114 stat->merges[group] += ptr->merges[group];115 }116 117 stat->io_ticks += ptr->io_ticks;118 }119}120 121unsigned int part_in_flight(struct block_device *part)122{123 unsigned int inflight = 0;124 int cpu;125 126 for_each_possible_cpu(cpu) {127 inflight += part_stat_local_read_cpu(part, in_flight[0], cpu) +128 part_stat_local_read_cpu(part, in_flight[1], cpu);129 }130 if ((int)inflight < 0)131 inflight = 0;132 133 return inflight;134}135 136static void part_in_flight_rw(struct block_device *part,137 unsigned int inflight[2])138{139 int cpu;140 141 inflight[0] = 0;142 inflight[1] = 0;143 for_each_possible_cpu(cpu) {144 inflight[0] += part_stat_local_read_cpu(part, in_flight[0], cpu);145 inflight[1] += part_stat_local_read_cpu(part, in_flight[1], cpu);146 }147 if ((int)inflight[0] < 0)148 inflight[0] = 0;149 if ((int)inflight[1] < 0)150 inflight[1] = 0;151}152 153/*154 * Can be deleted altogether. Later.155 *156 */157#define BLKDEV_MAJOR_HASH_SIZE 255158static struct blk_major_name {159 struct blk_major_name *next;160 int major;161 char name[16];162#ifdef CONFIG_BLOCK_LEGACY_AUTOLOAD163 void (*probe)(dev_t devt);164#endif165} *major_names[BLKDEV_MAJOR_HASH_SIZE];166static DEFINE_MUTEX(major_names_lock);167static DEFINE_SPINLOCK(major_names_spinlock);168 169/* index in the above - for now: assume no multimajor ranges */170static inline int major_to_index(unsigned major)171{172 return major % BLKDEV_MAJOR_HASH_SIZE;173}174 175#ifdef CONFIG_PROC_FS176void blkdev_show(struct seq_file *seqf, off_t offset)177{178 struct blk_major_name *dp;179 180 spin_lock(&major_names_spinlock);181 for (dp = major_names[major_to_index(offset)]; dp; dp = dp->next)182 if (dp->major == offset)183 seq_printf(seqf, "%3d %s\n", dp->major, dp->name);184 spin_unlock(&major_names_spinlock);185}186#endif /* CONFIG_PROC_FS */187 188/**189 * __register_blkdev - register a new block device190 *191 * @major: the requested major device number [1..BLKDEV_MAJOR_MAX-1]. If192 * @major = 0, try to allocate any unused major number.193 * @name: the name of the new block device as a zero terminated string194 * @probe: pre-devtmpfs / pre-udev callback used to create disks when their195 * pre-created device node is accessed. When a probe call uses196 * add_disk() and it fails the driver must cleanup resources. This197 * interface may soon be removed.198 *199 * The @name must be unique within the system.200 *201 * The return value depends on the @major input parameter:202 *203 * - if a major device number was requested in range [1..BLKDEV_MAJOR_MAX-1]204 * then the function returns zero on success, or a negative error code205 * - if any unused major number was requested with @major = 0 parameter206 * then the return value is the allocated major number in range207 * [1..BLKDEV_MAJOR_MAX-1] or a negative error code otherwise208 *209 * See Documentation/admin-guide/devices.txt for the list of allocated210 * major numbers.211 *212 * Use register_blkdev instead for any new code.213 */214int __register_blkdev(unsigned int major, const char *name,215 void (*probe)(dev_t devt))216{217 struct blk_major_name **n, *p;218 int index, ret = 0;219 220 mutex_lock(&major_names_lock);221 222 /* temporary */223 if (major == 0) {224 for (index = ARRAY_SIZE(major_names)-1; index > 0; index--) {225 if (major_names[index] == NULL)226 break;227 }228 229 if (index == 0) {230 printk("%s: failed to get major for %s\n",231 __func__, name);232 ret = -EBUSY;233 goto out;234 }235 major = index;236 ret = major;237 }238 239 if (major >= BLKDEV_MAJOR_MAX) {240 pr_err("%s: major requested (%u) is greater than the maximum (%u) for %s\n",241 __func__, major, BLKDEV_MAJOR_MAX-1, name);242 243 ret = -EINVAL;244 goto out;245 }246 247 p = kmalloc(sizeof(struct blk_major_name), GFP_KERNEL);248 if (p == NULL) {249 ret = -ENOMEM;250 goto out;251 }252 253 p->major = major;254#ifdef CONFIG_BLOCK_LEGACY_AUTOLOAD255 p->probe = probe;256#endif257 strscpy(p->name, name, sizeof(p->name));258 p->next = NULL;259 index = major_to_index(major);260 261 spin_lock(&major_names_spinlock);262 for (n = &major_names[index]; *n; n = &(*n)->next) {263 if ((*n)->major == major)264 break;265 }266 if (!*n)267 *n = p;268 else269 ret = -EBUSY;270 spin_unlock(&major_names_spinlock);271 272 if (ret < 0) {273 printk("register_blkdev: cannot get major %u for %s\n",274 major, name);275 kfree(p);276 }277out:278 mutex_unlock(&major_names_lock);279 return ret;280}281EXPORT_SYMBOL(__register_blkdev);282 283void unregister_blkdev(unsigned int major, const char *name)284{285 struct blk_major_name **n;286 struct blk_major_name *p = NULL;287 int index = major_to_index(major);288 289 mutex_lock(&major_names_lock);290 spin_lock(&major_names_spinlock);291 for (n = &major_names[index]; *n; n = &(*n)->next)292 if ((*n)->major == major)293 break;294 if (!*n || strcmp((*n)->name, name)) {295 WARN_ON(1);296 } else {297 p = *n;298 *n = p->next;299 }300 spin_unlock(&major_names_spinlock);301 mutex_unlock(&major_names_lock);302 kfree(p);303}304 305EXPORT_SYMBOL(unregister_blkdev);306 307int blk_alloc_ext_minor(void)308{309 int idx;310 311 idx = ida_alloc_range(&ext_devt_ida, 0, NR_EXT_DEVT - 1, GFP_KERNEL);312 if (idx == -ENOSPC)313 return -EBUSY;314 return idx;315}316 317void blk_free_ext_minor(unsigned int minor)318{319 ida_free(&ext_devt_ida, minor);320}321 322void disk_uevent(struct gendisk *disk, enum kobject_action action)323{324 struct block_device *part;325 unsigned long idx;326 327 rcu_read_lock();328 xa_for_each(&disk->part_tbl, idx, part) {329 if (bdev_is_partition(part) && !bdev_nr_sectors(part))330 continue;331 if (!kobject_get_unless_zero(&part->bd_device.kobj))332 continue;333 334 rcu_read_unlock();335 kobject_uevent(bdev_kobj(part), action);336 put_device(&part->bd_device);337 rcu_read_lock();338 }339 rcu_read_unlock();340}341EXPORT_SYMBOL_GPL(disk_uevent);342 343int disk_scan_partitions(struct gendisk *disk, blk_mode_t mode)344{345 struct file *file;346 int ret = 0;347 348 if (!disk_has_partscan(disk))349 return -EINVAL;350 if (disk->open_partitions)351 return -EBUSY;352 353 /*354 * If the device is opened exclusively by current thread already, it's355 * safe to scan partitons, otherwise, use bd_prepare_to_claim() to356 * synchronize with other exclusive openers and other partition357 * scanners.358 */359 if (!(mode & BLK_OPEN_EXCL)) {360 ret = bd_prepare_to_claim(disk->part0, disk_scan_partitions,361 NULL);362 if (ret)363 return ret;364 }365 366 set_bit(GD_NEED_PART_SCAN, &disk->state);367 file = bdev_file_open_by_dev(disk_devt(disk), mode & ~BLK_OPEN_EXCL,368 NULL, NULL);369 if (IS_ERR(file))370 ret = PTR_ERR(file);371 else372 fput(file);373 374 /*375 * If blkdev_get_by_dev() failed early, GD_NEED_PART_SCAN is still set,376 * and this will cause that re-assemble partitioned raid device will377 * creat partition for underlying disk.378 */379 clear_bit(GD_NEED_PART_SCAN, &disk->state);380 if (!(mode & BLK_OPEN_EXCL))381 bd_abort_claiming(disk->part0, disk_scan_partitions);382 return ret;383}384 385/**386 * device_add_disk - add disk information to kernel list387 * @parent: parent device for the disk388 * @disk: per-device partitioning information389 * @groups: Additional per-device sysfs groups390 *391 * This function registers the partitioning information in @disk392 * with the kernel.393 */394int __must_check device_add_disk(struct device *parent, struct gendisk *disk,395 const struct attribute_group **groups)396 397{398 struct device *ddev = disk_to_dev(disk);399 int ret;400 401 /* Only makes sense for bio-based to set ->poll_bio */402 if (queue_is_mq(disk->queue) && disk->fops->poll_bio)403 return -EINVAL;404 405 /*406 * The disk queue should now be all set with enough information about407 * the device for the elevator code to pick an adequate default408 * elevator if one is needed, that is, for devices requesting queue409 * registration.410 */411 elevator_init_mq(disk->queue);412 413 /* Mark bdev as having a submit_bio, if needed */414 if (disk->fops->submit_bio)415 bdev_set_flag(disk->part0, BD_HAS_SUBMIT_BIO);416 417 /*418 * If the driver provides an explicit major number it also must provide419 * the number of minors numbers supported, and those will be used to420 * setup the gendisk.421 * Otherwise just allocate the device numbers for both the whole device422 * and all partitions from the extended dev_t space.423 */424 ret = -EINVAL;425 if (disk->major) {426 if (WARN_ON(!disk->minors))427 goto out_exit_elevator;428 429 if (disk->minors > DISK_MAX_PARTS) {430 pr_err("block: can't allocate more than %d partitions\n",431 DISK_MAX_PARTS);432 disk->minors = DISK_MAX_PARTS;433 }434 if (disk->first_minor > MINORMASK ||435 disk->minors > MINORMASK + 1 ||436 disk->first_minor + disk->minors > MINORMASK + 1)437 goto out_exit_elevator;438 } else {439 if (WARN_ON(disk->minors))440 goto out_exit_elevator;441 442 ret = blk_alloc_ext_minor();443 if (ret < 0)444 goto out_exit_elevator;445 disk->major = BLOCK_EXT_MAJOR;446 disk->first_minor = ret;447 }448 449 /* delay uevents, until we scanned partition table */450 dev_set_uevent_suppress(ddev, 1);451 452 ddev->parent = parent;453 ddev->groups = groups;454 dev_set_name(ddev, "%s", disk->disk_name);455 if (!(disk->flags & GENHD_FL_HIDDEN))456 ddev->devt = MKDEV(disk->major, disk->first_minor);457 ret = device_add(ddev);458 if (ret)459 goto out_free_ext_minor;460 461 ret = disk_alloc_events(disk);462 if (ret)463 goto out_device_del;464 465 ret = sysfs_create_link(block_depr, &ddev->kobj,466 kobject_name(&ddev->kobj));467 if (ret)468 goto out_device_del;469 470 /*471 * avoid probable deadlock caused by allocating memory with472 * GFP_KERNEL in runtime_resume callback of its all ancestor473 * devices474 */475 pm_runtime_set_memalloc_noio(ddev, true);476 477 disk->part0->bd_holder_dir =478 kobject_create_and_add("holders", &ddev->kobj);479 if (!disk->part0->bd_holder_dir) {480 ret = -ENOMEM;481 goto out_del_block_link;482 }483 disk->slave_dir = kobject_create_and_add("slaves", &ddev->kobj);484 if (!disk->slave_dir) {485 ret = -ENOMEM;486 goto out_put_holder_dir;487 }488 489 ret = blk_register_queue(disk);490 if (ret)491 goto out_put_slave_dir;492 493 if (!(disk->flags & GENHD_FL_HIDDEN)) {494 ret = bdi_register(disk->bdi, "%u:%u",495 disk->major, disk->first_minor);496 if (ret)497 goto out_unregister_queue;498 bdi_set_owner(disk->bdi, ddev);499 ret = sysfs_create_link(&ddev->kobj,500 &disk->bdi->dev->kobj, "bdi");501 if (ret)502 goto out_unregister_bdi;503 504 /* Make sure the first partition scan will be proceed */505 if (get_capacity(disk) && disk_has_partscan(disk))506 set_bit(GD_NEED_PART_SCAN, &disk->state);507 508 bdev_add(disk->part0, ddev->devt);509 if (get_capacity(disk))510 disk_scan_partitions(disk, BLK_OPEN_READ);511 512 /*513 * Announce the disk and partitions after all partitions are514 * created. (for hidden disks uevents remain suppressed forever)515 */516 dev_set_uevent_suppress(ddev, 0);517 disk_uevent(disk, KOBJ_ADD);518 } else {519 /*520 * Even if the block_device for a hidden gendisk is not521 * registered, it needs to have a valid bd_dev so that the522 * freeing of the dynamic major works.523 */524 disk->part0->bd_dev = MKDEV(disk->major, disk->first_minor);525 }526 527 blk_apply_bdi_limits(disk->bdi, &disk->queue->limits);528 disk_add_events(disk);529 set_bit(GD_ADDED, &disk->state);530 return 0;531 532out_unregister_bdi:533 if (!(disk->flags & GENHD_FL_HIDDEN))534 bdi_unregister(disk->bdi);535out_unregister_queue:536 blk_unregister_queue(disk);537 rq_qos_exit(disk->queue);538out_put_slave_dir:539 kobject_put(disk->slave_dir);540 disk->slave_dir = NULL;541out_put_holder_dir:542 kobject_put(disk->part0->bd_holder_dir);543out_del_block_link:544 sysfs_remove_link(block_depr, dev_name(ddev));545 pm_runtime_set_memalloc_noio(ddev, false);546out_device_del:547 device_del(ddev);548out_free_ext_minor:549 if (disk->major == BLOCK_EXT_MAJOR)550 blk_free_ext_minor(disk->first_minor);551out_exit_elevator:552 if (disk->queue->elevator)553 elevator_exit(disk->queue);554 return ret;555}556EXPORT_SYMBOL(device_add_disk);557 558static void blk_report_disk_dead(struct gendisk *disk, bool surprise)559{560 struct block_device *bdev;561 unsigned long idx;562 563 /*564 * On surprise disk removal, bdev_mark_dead() may call into file565 * systems below. Make it clear that we're expecting to not hold566 * disk->open_mutex.567 */568 lockdep_assert_not_held(&disk->open_mutex);569 570 rcu_read_lock();571 xa_for_each(&disk->part_tbl, idx, bdev) {572 if (!kobject_get_unless_zero(&bdev->bd_device.kobj))573 continue;574 rcu_read_unlock();575 576 bdev_mark_dead(bdev, surprise);577 578 put_device(&bdev->bd_device);579 rcu_read_lock();580 }581 rcu_read_unlock();582}583 584static void __blk_mark_disk_dead(struct gendisk *disk)585{586 /*587 * Fail any new I/O.588 */589 if (test_and_set_bit(GD_DEAD, &disk->state))590 return;591 592 if (test_bit(GD_OWNS_QUEUE, &disk->state))593 blk_queue_flag_set(QUEUE_FLAG_DYING, disk->queue);594 595 /*596 * Stop buffered writers from dirtying pages that can't be written out.597 */598 set_capacity(disk, 0);599 600 /*601 * Prevent new I/O from crossing bio_queue_enter().602 */603 blk_queue_start_drain(disk->queue);604}605 606/**607 * blk_mark_disk_dead - mark a disk as dead608 * @disk: disk to mark as dead609 *610 * Mark as disk as dead (e.g. surprise removed) and don't accept any new I/O611 * to this disk.612 */613void blk_mark_disk_dead(struct gendisk *disk)614{615 __blk_mark_disk_dead(disk);616 blk_report_disk_dead(disk, true);617}618EXPORT_SYMBOL_GPL(blk_mark_disk_dead);619 620/**621 * del_gendisk - remove the gendisk622 * @disk: the struct gendisk to remove623 *624 * Removes the gendisk and all its associated resources. This deletes the625 * partitions associated with the gendisk, and unregisters the associated626 * request_queue.627 *628 * This is the counter to the respective __device_add_disk() call.629 *630 * The final removal of the struct gendisk happens when its refcount reaches 0631 * with put_disk(), which should be called after del_gendisk(), if632 * __device_add_disk() was used.633 *634 * Drivers exist which depend on the release of the gendisk to be synchronous,635 * it should not be deferred.636 *637 * Context: can sleep638 */639void del_gendisk(struct gendisk *disk)640{641 struct request_queue *q = disk->queue;642 struct block_device *part;643 unsigned long idx;644 645 might_sleep();646 647 if (WARN_ON_ONCE(!disk_live(disk) && !(disk->flags & GENHD_FL_HIDDEN)))648 return;649 650 disk_del_events(disk);651 652 /*653 * Prevent new openers by unlinked the bdev inode.654 */655 mutex_lock(&disk->open_mutex);656 xa_for_each(&disk->part_tbl, idx, part)657 bdev_unhash(part);658 mutex_unlock(&disk->open_mutex);659 660 /*661 * Tell the file system to write back all dirty data and shut down if662 * it hasn't been notified earlier.663 */664 if (!test_bit(GD_DEAD, &disk->state))665 blk_report_disk_dead(disk, false);666 667 /*668 * Drop all partitions now that the disk is marked dead.669 */670 mutex_lock(&disk->open_mutex);671 __blk_mark_disk_dead(disk);672 xa_for_each_start(&disk->part_tbl, idx, part, 1)673 drop_partition(part);674 mutex_unlock(&disk->open_mutex);675 676 if (!(disk->flags & GENHD_FL_HIDDEN)) {677 sysfs_remove_link(&disk_to_dev(disk)->kobj, "bdi");678 679 /*680 * Unregister bdi before releasing device numbers (as they can681 * get reused and we'd get clashes in sysfs).682 */683 bdi_unregister(disk->bdi);684 }685 686 blk_unregister_queue(disk);687 688 kobject_put(disk->part0->bd_holder_dir);689 kobject_put(disk->slave_dir);690 disk->slave_dir = NULL;691 692 part_stat_set_all(disk->part0, 0);693 disk->part0->bd_stamp = 0;694 sysfs_remove_link(block_depr, dev_name(disk_to_dev(disk)));695 pm_runtime_set_memalloc_noio(disk_to_dev(disk), false);696 device_del(disk_to_dev(disk));697 698 blk_mq_freeze_queue_wait(q);699 700 blk_throtl_cancel_bios(disk);701 702 blk_sync_queue(q);703 blk_flush_integrity();704 705 if (queue_is_mq(q))706 blk_mq_cancel_work_sync(q);707 708 blk_mq_quiesce_queue(q);709 if (q->elevator) {710 mutex_lock(&q->sysfs_lock);711 elevator_exit(q);712 mutex_unlock(&q->sysfs_lock);713 }714 rq_qos_exit(q);715 blk_mq_unquiesce_queue(q);716 717 /*718 * If the disk does not own the queue, allow using passthrough requests719 * again. Else leave the queue frozen to fail all I/O.720 */721 if (!test_bit(GD_OWNS_QUEUE, &disk->state)) {722 blk_queue_flag_clear(QUEUE_FLAG_INIT_DONE, q);723 __blk_mq_unfreeze_queue(q, true);724 } else {725 if (queue_is_mq(q))726 blk_mq_exit_queue(q);727 }728}729EXPORT_SYMBOL(del_gendisk);730 731/**732 * invalidate_disk - invalidate the disk733 * @disk: the struct gendisk to invalidate734 *735 * A helper to invalidates the disk. It will clean the disk's associated736 * buffer/page caches and reset its internal states so that the disk737 * can be reused by the drivers.738 *739 * Context: can sleep740 */741void invalidate_disk(struct gendisk *disk)742{743 struct block_device *bdev = disk->part0;744 745 invalidate_bdev(bdev);746 bdev->bd_mapping->wb_err = 0;747 set_capacity(disk, 0);748}749EXPORT_SYMBOL(invalidate_disk);750 751/* sysfs access to bad-blocks list. */752static ssize_t disk_badblocks_show(struct device *dev,753 struct device_attribute *attr,754 char *page)755{756 struct gendisk *disk = dev_to_disk(dev);757 758 if (!disk->bb)759 return sprintf(page, "\n");760 761 return badblocks_show(disk->bb, page, 0);762}763 764static ssize_t disk_badblocks_store(struct device *dev,765 struct device_attribute *attr,766 const char *page, size_t len)767{768 struct gendisk *disk = dev_to_disk(dev);769 770 if (!disk->bb)771 return -ENXIO;772 773 return badblocks_store(disk->bb, page, len, 0);774}775 776#ifdef CONFIG_BLOCK_LEGACY_AUTOLOAD777void blk_request_module(dev_t devt)778{779 unsigned int major = MAJOR(devt);780 struct blk_major_name **n;781 782 mutex_lock(&major_names_lock);783 for (n = &major_names[major_to_index(major)]; *n; n = &(*n)->next) {784 if ((*n)->major == major && (*n)->probe) {785 (*n)->probe(devt);786 mutex_unlock(&major_names_lock);787 return;788 }789 }790 mutex_unlock(&major_names_lock);791 792 if (request_module("block-major-%d-%d", MAJOR(devt), MINOR(devt)) > 0)793 /* Make old-style 2.4 aliases work */794 request_module("block-major-%d", MAJOR(devt));795}796#endif /* CONFIG_BLOCK_LEGACY_AUTOLOAD */797 798#ifdef CONFIG_PROC_FS799/* iterator */800static void *disk_seqf_start(struct seq_file *seqf, loff_t *pos)801{802 loff_t skip = *pos;803 struct class_dev_iter *iter;804 struct device *dev;805 806 iter = kmalloc(sizeof(*iter), GFP_KERNEL);807 if (!iter)808 return ERR_PTR(-ENOMEM);809 810 seqf->private = iter;811 class_dev_iter_init(iter, &block_class, NULL, &disk_type);812 do {813 dev = class_dev_iter_next(iter);814 if (!dev)815 return NULL;816 } while (skip--);817 818 return dev_to_disk(dev);819}820 821static void *disk_seqf_next(struct seq_file *seqf, void *v, loff_t *pos)822{823 struct device *dev;824 825 (*pos)++;826 dev = class_dev_iter_next(seqf->private);827 if (dev)828 return dev_to_disk(dev);829 830 return NULL;831}832 833static void disk_seqf_stop(struct seq_file *seqf, void *v)834{835 struct class_dev_iter *iter = seqf->private;836 837 /* stop is called even after start failed :-( */838 if (iter) {839 class_dev_iter_exit(iter);840 kfree(iter);841 seqf->private = NULL;842 }843}844 845static void *show_partition_start(struct seq_file *seqf, loff_t *pos)846{847 void *p;848 849 p = disk_seqf_start(seqf, pos);850 if (!IS_ERR_OR_NULL(p) && !*pos)851 seq_puts(seqf, "major minor #blocks name\n\n");852 return p;853}854 855static int show_partition(struct seq_file *seqf, void *v)856{857 struct gendisk *sgp = v;858 struct block_device *part;859 unsigned long idx;860 861 if (!get_capacity(sgp) || (sgp->flags & GENHD_FL_HIDDEN))862 return 0;863 864 rcu_read_lock();865 xa_for_each(&sgp->part_tbl, idx, part) {866 if (!bdev_nr_sectors(part))867 continue;868 seq_printf(seqf, "%4d %7d %10llu %pg\n",869 MAJOR(part->bd_dev), MINOR(part->bd_dev),870 bdev_nr_sectors(part) >> 1, part);871 }872 rcu_read_unlock();873 return 0;874}875 876static const struct seq_operations partitions_op = {877 .start = show_partition_start,878 .next = disk_seqf_next,879 .stop = disk_seqf_stop,880 .show = show_partition881};882#endif883 884static int __init genhd_device_init(void)885{886 int error;887 888 error = class_register(&block_class);889 if (unlikely(error))890 return error;891 blk_dev_init();892 893 register_blkdev(BLOCK_EXT_MAJOR, "blkext");894 895 /* create top-level block dir */896 block_depr = kobject_create_and_add("block", NULL);897 return 0;898}899 900subsys_initcall(genhd_device_init);901 902static ssize_t disk_range_show(struct device *dev,903 struct device_attribute *attr, char *buf)904{905 struct gendisk *disk = dev_to_disk(dev);906 907 return sprintf(buf, "%d\n", disk->minors);908}909 910static ssize_t disk_ext_range_show(struct device *dev,911 struct device_attribute *attr, char *buf)912{913 struct gendisk *disk = dev_to_disk(dev);914 915 return sprintf(buf, "%d\n",916 (disk->flags & GENHD_FL_NO_PART) ? 1 : DISK_MAX_PARTS);917}918 919static ssize_t disk_removable_show(struct device *dev,920 struct device_attribute *attr, char *buf)921{922 struct gendisk *disk = dev_to_disk(dev);923 924 return sprintf(buf, "%d\n",925 (disk->flags & GENHD_FL_REMOVABLE ? 1 : 0));926}927 928static ssize_t disk_hidden_show(struct device *dev,929 struct device_attribute *attr, char *buf)930{931 struct gendisk *disk = dev_to_disk(dev);932 933 return sprintf(buf, "%d\n",934 (disk->flags & GENHD_FL_HIDDEN ? 1 : 0));935}936 937static ssize_t disk_ro_show(struct device *dev,938 struct device_attribute *attr, char *buf)939{940 struct gendisk *disk = dev_to_disk(dev);941 942 return sprintf(buf, "%d\n", get_disk_ro(disk) ? 1 : 0);943}944 945ssize_t part_size_show(struct device *dev,946 struct device_attribute *attr, char *buf)947{948 return sprintf(buf, "%llu\n", bdev_nr_sectors(dev_to_bdev(dev)));949}950 951ssize_t part_stat_show(struct device *dev,952 struct device_attribute *attr, char *buf)953{954 struct block_device *bdev = dev_to_bdev(dev);955 struct disk_stats stat;956 unsigned int inflight;957 958 inflight = part_in_flight(bdev);959 if (inflight) {960 part_stat_lock();961 update_io_ticks(bdev, jiffies, true);962 part_stat_unlock();963 }964 part_stat_read_all(bdev, &stat);965 return sprintf(buf,966 "%8lu %8lu %8llu %8u "967 "%8lu %8lu %8llu %8u "968 "%8u %8u %8u "969 "%8lu %8lu %8llu %8u "970 "%8lu %8u"971 "\n",972 stat.ios[STAT_READ],973 stat.merges[STAT_READ],974 (unsigned long long)stat.sectors[STAT_READ],975 (unsigned int)div_u64(stat.nsecs[STAT_READ], NSEC_PER_MSEC),976 stat.ios[STAT_WRITE],977 stat.merges[STAT_WRITE],978 (unsigned long long)stat.sectors[STAT_WRITE],979 (unsigned int)div_u64(stat.nsecs[STAT_WRITE], NSEC_PER_MSEC),980 inflight,981 jiffies_to_msecs(stat.io_ticks),982 (unsigned int)div_u64(stat.nsecs[STAT_READ] +983 stat.nsecs[STAT_WRITE] +984 stat.nsecs[STAT_DISCARD] +985 stat.nsecs[STAT_FLUSH],986 NSEC_PER_MSEC),987 stat.ios[STAT_DISCARD],988 stat.merges[STAT_DISCARD],989 (unsigned long long)stat.sectors[STAT_DISCARD],990 (unsigned int)div_u64(stat.nsecs[STAT_DISCARD], NSEC_PER_MSEC),991 stat.ios[STAT_FLUSH],992 (unsigned int)div_u64(stat.nsecs[STAT_FLUSH], NSEC_PER_MSEC));993}994 995ssize_t part_inflight_show(struct device *dev, struct device_attribute *attr,996 char *buf)997{998 struct block_device *bdev = dev_to_bdev(dev);999 struct request_queue *q = bdev_get_queue(bdev);1000 unsigned int inflight[2];1001 1002 if (queue_is_mq(q))1003 blk_mq_in_flight_rw(q, bdev, inflight);1004 else1005 part_in_flight_rw(bdev, inflight);1006 1007 return sprintf(buf, "%8u %8u\n", inflight[0], inflight[1]);1008}1009 1010static ssize_t disk_capability_show(struct device *dev,1011 struct device_attribute *attr, char *buf)1012{1013 dev_warn_once(dev, "the capability attribute has been deprecated.\n");1014 return sprintf(buf, "0\n");1015}1016 1017static ssize_t disk_alignment_offset_show(struct device *dev,1018 struct device_attribute *attr,1019 char *buf)1020{1021 struct gendisk *disk = dev_to_disk(dev);1022 1023 return sprintf(buf, "%d\n", bdev_alignment_offset(disk->part0));1024}1025 1026static ssize_t disk_discard_alignment_show(struct device *dev,1027 struct device_attribute *attr,1028 char *buf)1029{1030 struct gendisk *disk = dev_to_disk(dev);1031 1032 return sprintf(buf, "%d\n", bdev_alignment_offset(disk->part0));1033}1034 1035static ssize_t diskseq_show(struct device *dev,1036 struct device_attribute *attr, char *buf)1037{1038 struct gendisk *disk = dev_to_disk(dev);1039 1040 return sprintf(buf, "%llu\n", disk->diskseq);1041}1042 1043static ssize_t partscan_show(struct device *dev,1044 struct device_attribute *attr, char *buf)1045{1046 return sprintf(buf, "%u\n", disk_has_partscan(dev_to_disk(dev)));1047}1048 1049static DEVICE_ATTR(range, 0444, disk_range_show, NULL);1050static DEVICE_ATTR(ext_range, 0444, disk_ext_range_show, NULL);1051static DEVICE_ATTR(removable, 0444, disk_removable_show, NULL);1052static DEVICE_ATTR(hidden, 0444, disk_hidden_show, NULL);1053static DEVICE_ATTR(ro, 0444, disk_ro_show, NULL);1054static DEVICE_ATTR(size, 0444, part_size_show, NULL);1055static DEVICE_ATTR(alignment_offset, 0444, disk_alignment_offset_show, NULL);1056static DEVICE_ATTR(discard_alignment, 0444, disk_discard_alignment_show, NULL);1057static DEVICE_ATTR(capability, 0444, disk_capability_show, NULL);1058static DEVICE_ATTR(stat, 0444, part_stat_show, NULL);1059static DEVICE_ATTR(inflight, 0444, part_inflight_show, NULL);1060static DEVICE_ATTR(badblocks, 0644, disk_badblocks_show, disk_badblocks_store);1061static DEVICE_ATTR(diskseq, 0444, diskseq_show, NULL);1062static DEVICE_ATTR(partscan, 0444, partscan_show, NULL);1063 1064#ifdef CONFIG_FAIL_MAKE_REQUEST1065ssize_t part_fail_show(struct device *dev,1066 struct device_attribute *attr, char *buf)1067{1068 return sprintf(buf, "%d\n",1069 bdev_test_flag(dev_to_bdev(dev), BD_MAKE_IT_FAIL));1070}1071 1072ssize_t part_fail_store(struct device *dev,1073 struct device_attribute *attr,1074 const char *buf, size_t count)1075{1076 int i;1077 1078 if (count > 0 && sscanf(buf, "%d", &i) > 0) {1079 if (i)1080 bdev_set_flag(dev_to_bdev(dev), BD_MAKE_IT_FAIL);1081 else1082 bdev_clear_flag(dev_to_bdev(dev), BD_MAKE_IT_FAIL);1083 }1084 return count;1085}1086 1087static struct device_attribute dev_attr_fail =1088 __ATTR(make-it-fail, 0644, part_fail_show, part_fail_store);1089#endif /* CONFIG_FAIL_MAKE_REQUEST */1090 1091#ifdef CONFIG_FAIL_IO_TIMEOUT1092static struct device_attribute dev_attr_fail_timeout =1093 __ATTR(io-timeout-fail, 0644, part_timeout_show, part_timeout_store);1094#endif1095 1096static struct attribute *disk_attrs[] = {1097 &dev_attr_range.attr,1098 &dev_attr_ext_range.attr,1099 &dev_attr_removable.attr,1100 &dev_attr_hidden.attr,1101 &dev_attr_ro.attr,1102 &dev_attr_size.attr,1103 &dev_attr_alignment_offset.attr,1104 &dev_attr_discard_alignment.attr,1105 &dev_attr_capability.attr,1106 &dev_attr_stat.attr,1107 &dev_attr_inflight.attr,1108 &dev_attr_badblocks.attr,1109 &dev_attr_events.attr,1110 &dev_attr_events_async.attr,1111 &dev_attr_events_poll_msecs.attr,1112 &dev_attr_diskseq.attr,1113 &dev_attr_partscan.attr,1114#ifdef CONFIG_FAIL_MAKE_REQUEST1115 &dev_attr_fail.attr,1116#endif1117#ifdef CONFIG_FAIL_IO_TIMEOUT1118 &dev_attr_fail_timeout.attr,1119#endif1120 NULL1121};1122 1123static umode_t disk_visible(struct kobject *kobj, struct attribute *a, int n)1124{1125 struct device *dev = container_of(kobj, typeof(*dev), kobj);1126 struct gendisk *disk = dev_to_disk(dev);1127 1128 if (a == &dev_attr_badblocks.attr && !disk->bb)1129 return 0;1130 return a->mode;1131}1132 1133static struct attribute_group disk_attr_group = {1134 .attrs = disk_attrs,1135 .is_visible = disk_visible,1136};1137 1138static const struct attribute_group *disk_attr_groups[] = {1139 &disk_attr_group,1140#ifdef CONFIG_BLK_DEV_IO_TRACE1141 &blk_trace_attr_group,1142#endif1143#ifdef CONFIG_BLK_DEV_INTEGRITY1144 &blk_integrity_attr_group,1145#endif1146 NULL1147};1148 1149/**1150 * disk_release - releases all allocated resources of the gendisk1151 * @dev: the device representing this disk1152 *1153 * This function releases all allocated resources of the gendisk.1154 *1155 * Drivers which used __device_add_disk() have a gendisk with a request_queue1156 * assigned. Since the request_queue sits on top of the gendisk for these1157 * drivers we also call blk_put_queue() for them, and we expect the1158 * request_queue refcount to reach 0 at this point, and so the request_queue1159 * will also be freed prior to the disk.1160 *1161 * Context: can sleep1162 */1163static void disk_release(struct device *dev)1164{1165 struct gendisk *disk = dev_to_disk(dev);1166 1167 might_sleep();1168 WARN_ON_ONCE(disk_live(disk));1169 1170 blk_trace_remove(disk->queue);1171 1172 /*1173 * To undo the all initialization from blk_mq_init_allocated_queue in1174 * case of a probe failure where add_disk is never called we have to1175 * call blk_mq_exit_queue here. We can't do this for the more common1176 * teardown case (yet) as the tagset can be gone by the time the disk1177 * is released once it was added.1178 */1179 if (queue_is_mq(disk->queue) &&1180 test_bit(GD_OWNS_QUEUE, &disk->state) &&1181 !test_bit(GD_ADDED, &disk->state))1182 blk_mq_exit_queue(disk->queue);1183 1184 blkcg_exit_disk(disk);1185 1186 bioset_exit(&disk->bio_split);1187 1188 disk_release_events(disk);1189 kfree(disk->random);1190 disk_free_zone_resources(disk);1191 xa_destroy(&disk->part_tbl);1192 1193 disk->queue->disk = NULL;1194 blk_put_queue(disk->queue);1195 1196 if (test_bit(GD_ADDED, &disk->state) && disk->fops->free_disk)1197 disk->fops->free_disk(disk);1198 1199 bdev_drop(disk->part0); /* frees the disk */1200}1201 1202static int block_uevent(const struct device *dev, struct kobj_uevent_env *env)1203{1204 const struct gendisk *disk = dev_to_disk(dev);1205 1206 return add_uevent_var(env, "DISKSEQ=%llu", disk->diskseq);1207}1208 1209const struct class block_class = {1210 .name = "block",1211 .dev_uevent = block_uevent,1212};1213 1214static char *block_devnode(const struct device *dev, umode_t *mode,1215 kuid_t *uid, kgid_t *gid)1216{1217 struct gendisk *disk = dev_to_disk(dev);1218 1219 if (disk->fops->devnode)1220 return disk->fops->devnode(disk, mode);1221 return NULL;1222}1223 1224const struct device_type disk_type = {1225 .name = "disk",1226 .groups = disk_attr_groups,1227 .release = disk_release,1228 .devnode = block_devnode,1229};1230 1231#ifdef CONFIG_PROC_FS1232/*1233 * aggregate disk stat collector. Uses the same stats that the sysfs1234 * entries do, above, but makes them available through one seq_file.1235 *1236 * The output looks suspiciously like /proc/partitions with a bunch of1237 * extra fields.1238 */1239static int diskstats_show(struct seq_file *seqf, void *v)1240{1241 struct gendisk *gp = v;1242 struct block_device *hd;1243 unsigned int inflight;1244 struct disk_stats stat;1245 unsigned long idx;1246 1247 /*1248 if (&disk_to_dev(gp)->kobj.entry == block_class.devices.next)1249 seq_puts(seqf, "major minor name"1250 " rio rmerge rsect ruse wio wmerge "1251 "wsect wuse running use aveq"1252 "\n\n");1253 */1254 1255 rcu_read_lock();1256 xa_for_each(&gp->part_tbl, idx, hd) {1257 if (bdev_is_partition(hd) && !bdev_nr_sectors(hd))1258 continue;1259 1260 inflight = part_in_flight(hd);1261 if (inflight) {1262 part_stat_lock();1263 update_io_ticks(hd, jiffies, true);1264 part_stat_unlock();1265 }1266 part_stat_read_all(hd, &stat);1267 seq_printf(seqf, "%4d %7d %pg "1268 "%lu %lu %lu %u "1269 "%lu %lu %lu %u "1270 "%u %u %u "1271 "%lu %lu %lu %u "1272 "%lu %u"1273 "\n",1274 MAJOR(hd->bd_dev), MINOR(hd->bd_dev), hd,1275 stat.ios[STAT_READ],1276 stat.merges[STAT_READ],1277 stat.sectors[STAT_READ],1278 (unsigned int)div_u64(stat.nsecs[STAT_READ],1279 NSEC_PER_MSEC),1280 stat.ios[STAT_WRITE],1281 stat.merges[STAT_WRITE],1282 stat.sectors[STAT_WRITE],1283 (unsigned int)div_u64(stat.nsecs[STAT_WRITE],1284 NSEC_PER_MSEC),1285 inflight,1286 jiffies_to_msecs(stat.io_ticks),1287 (unsigned int)div_u64(stat.nsecs[STAT_READ] +1288 stat.nsecs[STAT_WRITE] +1289 stat.nsecs[STAT_DISCARD] +1290 stat.nsecs[STAT_FLUSH],1291 NSEC_PER_MSEC),1292 stat.ios[STAT_DISCARD],1293 stat.merges[STAT_DISCARD],1294 stat.sectors[STAT_DISCARD],1295 (unsigned int)div_u64(stat.nsecs[STAT_DISCARD],1296 NSEC_PER_MSEC),1297 stat.ios[STAT_FLUSH],1298 (unsigned int)div_u64(stat.nsecs[STAT_FLUSH],1299 NSEC_PER_MSEC)1300 );1301 }1302 rcu_read_unlock();1303 1304 return 0;1305}1306 1307static const struct seq_operations diskstats_op = {1308 .start = disk_seqf_start,1309 .next = disk_seqf_next,1310 .stop = disk_seqf_stop,1311 .show = diskstats_show1312};1313 1314static int __init proc_genhd_init(void)1315{1316 proc_create_seq("diskstats", 0, NULL, &diskstats_op);1317 proc_create_seq("partitions", 0, NULL, &partitions_op);1318 return 0;1319}1320module_init(proc_genhd_init);1321#endif /* CONFIG_PROC_FS */1322 1323dev_t part_devt(struct gendisk *disk, u8 partno)1324{1325 struct block_device *part;1326 dev_t devt = 0;1327 1328 rcu_read_lock();1329 part = xa_load(&disk->part_tbl, partno);1330 if (part)1331 devt = part->bd_dev;1332 rcu_read_unlock();1333 1334 return devt;1335}1336 1337struct gendisk *__alloc_disk_node(struct request_queue *q, int node_id,1338 struct lock_class_key *lkclass)1339{1340 struct gendisk *disk;1341 1342 disk = kzalloc_node(sizeof(struct gendisk), GFP_KERNEL, node_id);1343 if (!disk)1344 return NULL;1345 1346 if (bioset_init(&disk->bio_split, BIO_POOL_SIZE, 0, 0))1347 goto out_free_disk;1348 1349 disk->bdi = bdi_alloc(node_id);1350 if (!disk->bdi)1351 goto out_free_bioset;1352 1353 /* bdev_alloc() might need the queue, set before the first call */1354 disk->queue = q;1355 1356 disk->part0 = bdev_alloc(disk, 0);1357 if (!disk->part0)1358 goto out_free_bdi;1359 1360 disk->node_id = node_id;1361 mutex_init(&disk->open_mutex);1362 xa_init(&disk->part_tbl);1363 if (xa_insert(&disk->part_tbl, 0, disk->part0, GFP_KERNEL))1364 goto out_destroy_part_tbl;1365 1366 if (blkcg_init_disk(disk))1367 goto out_erase_part0;1368 1369 disk_init_zone_resources(disk);1370 rand_initialize_disk(disk);1371 disk_to_dev(disk)->class = &block_class;1372 disk_to_dev(disk)->type = &disk_type;1373 device_initialize(disk_to_dev(disk));1374 inc_diskseq(disk);1375 q->disk = disk;1376 lockdep_init_map(&disk->lockdep_map, "(bio completion)", lkclass, 0);1377#ifdef CONFIG_BLOCK_HOLDER_DEPRECATED1378 INIT_LIST_HEAD(&disk->slave_bdevs);1379#endif1380 return disk;1381 1382out_erase_part0:1383 xa_erase(&disk->part_tbl, 0);1384out_destroy_part_tbl:1385 xa_destroy(&disk->part_tbl);1386 disk->part0->bd_disk = NULL;1387 bdev_drop(disk->part0);1388out_free_bdi:1389 bdi_put(disk->bdi);1390out_free_bioset:1391 bioset_exit(&disk->bio_split);1392out_free_disk:1393 kfree(disk);1394 return NULL;1395}1396 1397struct gendisk *__blk_alloc_disk(struct queue_limits *lim, int node,1398 struct lock_class_key *lkclass)1399{1400 struct queue_limits default_lim = { };1401 struct request_queue *q;1402 struct gendisk *disk;1403 1404 q = blk_alloc_queue(lim ? lim : &default_lim, node);1405 if (IS_ERR(q))1406 return ERR_CAST(q);1407 1408 disk = __alloc_disk_node(q, node, lkclass);1409 if (!disk) {1410 blk_put_queue(q);1411 return ERR_PTR(-ENOMEM);1412 }1413 set_bit(GD_OWNS_QUEUE, &disk->state);1414 return disk;1415}1416EXPORT_SYMBOL(__blk_alloc_disk);1417 1418/**1419 * put_disk - decrements the gendisk refcount1420 * @disk: the struct gendisk to decrement the refcount for1421 *1422 * This decrements the refcount for the struct gendisk. When this reaches 01423 * we'll have disk_release() called.1424 *1425 * Note: for blk-mq disk put_disk must be called before freeing the tag_set1426 * when handling probe errors (that is before add_disk() is called).1427 *1428 * Context: Any context, but the last reference must not be dropped from1429 * atomic context.1430 */1431void put_disk(struct gendisk *disk)1432{1433 if (disk)1434 put_device(disk_to_dev(disk));1435}1436EXPORT_SYMBOL(put_disk);1437 1438static void set_disk_ro_uevent(struct gendisk *gd, int ro)1439{1440 char event[] = "DISK_RO=1";1441 char *envp[] = { event, NULL };1442 1443 if (!ro)1444 event[8] = '0';1445 kobject_uevent_env(&disk_to_dev(gd)->kobj, KOBJ_CHANGE, envp);1446}1447 1448/**1449 * set_disk_ro - set a gendisk read-only1450 * @disk: gendisk to operate on1451 * @read_only: %true to set the disk read-only, %false set the disk read/write1452 *1453 * This function is used to indicate whether a given disk device should have its1454 * read-only flag set. set_disk_ro() is typically used by device drivers to1455 * indicate whether the underlying physical device is write-protected.1456 */1457void set_disk_ro(struct gendisk *disk, bool read_only)1458{1459 if (read_only) {1460 if (test_and_set_bit(GD_READ_ONLY, &disk->state))1461 return;1462 } else {1463 if (!test_and_clear_bit(GD_READ_ONLY, &disk->state))1464 return;1465 }1466 set_disk_ro_uevent(disk, read_only);1467}1468EXPORT_SYMBOL(set_disk_ro);1469 1470void inc_diskseq(struct gendisk *disk)1471{1472 disk->diskseq = atomic64_inc_return(&diskseq);1473}1474