1// SPDX-License-Identifier: GPL-2.0
2/*
3 * gendisk handling
4 *
5 * Portions Copyright (C) 2020 Christoph Hellwig
6 */
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 block
40 * 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 has
43 * a very high latency.
44 * Block devices do not have exclusive owners in userspace, any process can set
45 * one up (e.g. loop devices). Moreover, device names can be reused (e.g. loop0
46 * can be reused again and again).
47 * A userspace process setting up a block device and watching for its events
48 * cannot thus reliably tell whether an event relates to the device it just set
49 * up or another earlier instance with the same name.
50 * This sequential number allows userspace processes to solve this problem, and
51 * 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(bdev: 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 not
67 * 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 visible
78 * and alive. This avoids spamming the log and udev when setting the
79 * 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 empty
91 * device.
92 */
93 if (!capacity || !size)
94 return false;
95 kobject_uevent_env(kobj: &disk_to_dev(disk)->kobj, action: 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
121static unsigned 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 255
158static struct blk_major_name {
159 struct blk_major_name *next;
160 int major;
161 char name[16];
162#ifdef CONFIG_BLOCK_LEGACY_AUTOLOAD
163 void (*probe)(dev_t devt);
164#endif
165} *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_FS
176void blkdev_show(struct seq_file *seqf, off_t offset)
177{
178 struct blk_major_name *dp;
179
180 spin_lock(lock: &major_names_spinlock);
181 for (dp = major_names[major_to_index(major: offset)]; dp; dp = dp->next)
182 if (dp->major == offset)
183 seq_printf(m: seqf, fmt: "%3d %s\n", dp->major, dp->name);
184 spin_unlock(lock: &major_names_spinlock);
185}
186#endif /* CONFIG_PROC_FS */
187
188/**
189 * __register_blkdev - register a new block device
190 *
191 * @major: the requested major device number [1..BLKDEV_MAJOR_MAX-1]. If
192 * @major = 0, try to allocate any unused major number.
193 * @name: the name of the new block device as a zero terminated string
194 * @probe: pre-devtmpfs / pre-udev callback used to create disks when their
195 * pre-created device node is accessed. When a probe call uses
196 * add_disk() and it fails the driver must cleanup resources. This
197 * 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 code
205 * - if any unused major number was requested with @major = 0 parameter
206 * then the return value is the allocated major number in range
207 * [1..BLKDEV_MAJOR_MAX-1] or a negative error code otherwise
208 *
209 * See Documentation/admin-guide/devices.txt for the list of allocated
210 * 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(size: 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_AUTOLOAD
255 p->probe = probe;
256#endif
257 strscpy(p: p->name, q: name, size: sizeof(p->name));
258 p->next = NULL;
259 index = major_to_index(major);
260
261 spin_lock(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 else
269 ret = -EBUSY;
270 spin_unlock(lock: &major_names_spinlock);
271
272 if (ret < 0) {
273 printk("register_blkdev: cannot get major %u for %s\n",
274 major, name);
275 kfree(objp: p);
276 }
277out:
278 mutex_unlock(lock: &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(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(lock: &major_names_spinlock);
301 mutex_unlock(lock: &major_names_lock);
302 kfree(objp: 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, min: 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, id: 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(bdev: part) && !bdev_nr_sectors(bdev: part))
330 continue;
331 if (!kobject_get_unless_zero(kobj: &part->bd_device.kobj))
332 continue;
333
334 rcu_read_unlock();
335 kobject_uevent(bdev_kobj(part), action);
336 put_device(dev: &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 bdev_handle *handle;
346 int ret = 0;
347
348 if (disk->flags & (GENHD_FL_NO_PART | GENHD_FL_HIDDEN))
349 return -EINVAL;
350 if (test_bit(GD_SUPPRESS_PART_SCAN, &disk->state))
351 return -EINVAL;
352 if (disk->open_partitions)
353 return -EBUSY;
354
355 /*
356 * If the device is opened exclusively by current thread already, it's
357 * safe to scan partitons, otherwise, use bd_prepare_to_claim() to
358 * synchronize with other exclusive openers and other partition
359 * scanners.
360 */
361 if (!(mode & BLK_OPEN_EXCL)) {
362 ret = bd_prepare_to_claim(bdev: disk->part0, holder: disk_scan_partitions,
363 NULL);
364 if (ret)
365 return ret;
366 }
367
368 set_bit(GD_NEED_PART_SCAN, addr: &disk->state);
369 handle = bdev_open_by_dev(dev: disk_devt(disk), mode: mode & ~BLK_OPEN_EXCL, NULL,
370 NULL);
371 if (IS_ERR(ptr: handle))
372 ret = PTR_ERR(ptr: handle);
373 else
374 bdev_release(handle);
375
376 /*
377 * If blkdev_get_by_dev() failed early, GD_NEED_PART_SCAN is still set,
378 * and this will cause that re-assemble partitioned raid device will
379 * creat partition for underlying disk.
380 */
381 clear_bit(GD_NEED_PART_SCAN, addr: &disk->state);
382 if (!(mode & BLK_OPEN_EXCL))
383 bd_abort_claiming(bdev: disk->part0, holder: disk_scan_partitions);
384 return ret;
385}
386
387/**
388 * device_add_disk - add disk information to kernel list
389 * @parent: parent device for the disk
390 * @disk: per-device partitioning information
391 * @groups: Additional per-device sysfs groups
392 *
393 * This function registers the partitioning information in @disk
394 * with the kernel.
395 */
396int __must_check device_add_disk(struct device *parent, struct gendisk *disk,
397 const struct attribute_group **groups)
398
399{
400 struct device *ddev = disk_to_dev(disk);
401 int ret;
402
403 /* Only makes sense for bio-based to set ->poll_bio */
404 if (queue_is_mq(q: disk->queue) && disk->fops->poll_bio)
405 return -EINVAL;
406
407 /*
408 * The disk queue should now be all set with enough information about
409 * the device for the elevator code to pick an adequate default
410 * elevator if one is needed, that is, for devices requesting queue
411 * registration.
412 */
413 elevator_init_mq(q: disk->queue);
414
415 /* Mark bdev as having a submit_bio, if needed */
416 disk->part0->bd_has_submit_bio = disk->fops->submit_bio != NULL;
417
418 /*
419 * If the driver provides an explicit major number it also must provide
420 * the number of minors numbers supported, and those will be used to
421 * setup the gendisk.
422 * Otherwise just allocate the device numbers for both the whole device
423 * and all partitions from the extended dev_t space.
424 */
425 ret = -EINVAL;
426 if (disk->major) {
427 if (WARN_ON(!disk->minors))
428 goto out_exit_elevator;
429
430 if (disk->minors > DISK_MAX_PARTS) {
431 pr_err("block: can't allocate more than %d partitions\n",
432 DISK_MAX_PARTS);
433 disk->minors = DISK_MAX_PARTS;
434 }
435 if (disk->first_minor + disk->minors > MINORMASK + 1)
436 goto out_exit_elevator;
437 } else {
438 if (WARN_ON(disk->minors))
439 goto out_exit_elevator;
440
441 ret = blk_alloc_ext_minor();
442 if (ret < 0)
443 goto out_exit_elevator;
444 disk->major = BLOCK_EXT_MAJOR;
445 disk->first_minor = ret;
446 }
447
448 /* delay uevents, until we scanned partition table */
449 dev_set_uevent_suppress(dev: ddev, val: 1);
450
451 ddev->parent = parent;
452 ddev->groups = groups;
453 dev_set_name(dev: ddev, name: "%s", disk->disk_name);
454 if (!(disk->flags & GENHD_FL_HIDDEN))
455 ddev->devt = MKDEV(disk->major, disk->first_minor);
456 ret = device_add(dev: ddev);
457 if (ret)
458 goto out_free_ext_minor;
459
460 ret = disk_alloc_events(disk);
461 if (ret)
462 goto out_device_del;
463
464 ret = sysfs_create_link(kobj: block_depr, target: &ddev->kobj,
465 name: kobject_name(kobj: &ddev->kobj));
466 if (ret)
467 goto out_device_del;
468
469 /*
470 * avoid probable deadlock caused by allocating memory with
471 * GFP_KERNEL in runtime_resume callback of its all ancestor
472 * devices
473 */
474 pm_runtime_set_memalloc_noio(dev: ddev, enable: true);
475
476 disk->part0->bd_holder_dir =
477 kobject_create_and_add(name: "holders", parent: &ddev->kobj);
478 if (!disk->part0->bd_holder_dir) {
479 ret = -ENOMEM;
480 goto out_del_block_link;
481 }
482 disk->slave_dir = kobject_create_and_add(name: "slaves", parent: &ddev->kobj);
483 if (!disk->slave_dir) {
484 ret = -ENOMEM;
485 goto out_put_holder_dir;
486 }
487
488 ret = blk_register_queue(disk);
489 if (ret)
490 goto out_put_slave_dir;
491
492 if (!(disk->flags & GENHD_FL_HIDDEN)) {
493 ret = bdi_register(bdi: disk->bdi, fmt: "%u:%u",
494 disk->major, disk->first_minor);
495 if (ret)
496 goto out_unregister_queue;
497 bdi_set_owner(bdi: disk->bdi, owner: ddev);
498 ret = sysfs_create_link(kobj: &ddev->kobj,
499 target: &disk->bdi->dev->kobj, name: "bdi");
500 if (ret)
501 goto out_unregister_bdi;
502
503 /* Make sure the first partition scan will be proceed */
504 if (get_capacity(disk) && !(disk->flags & GENHD_FL_NO_PART) &&
505 !test_bit(GD_SUPPRESS_PART_SCAN, &disk->state))
506 set_bit(GD_NEED_PART_SCAN, addr: &disk->state);
507
508 bdev_add(bdev: disk->part0, dev: 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 are
514 * created. (for hidden disks uevents remain suppressed forever)
515 */
516 dev_set_uevent_suppress(dev: ddev, val: 0);
517 disk_uevent(disk, KOBJ_ADD);
518 } else {
519 /*
520 * Even if the block_device for a hidden gendisk is not
521 * registered, it needs to have a valid bd_dev so that the
522 * freeing of the dynamic major works.
523 */
524 disk->part0->bd_dev = MKDEV(disk->major, disk->first_minor);
525 }
526
527 disk_update_readahead(disk);
528 disk_add_events(disk);
529 set_bit(GD_ADDED, addr: &disk->state);
530 return 0;
531
532out_unregister_bdi:
533 if (!(disk->flags & GENHD_FL_HIDDEN))
534 bdi_unregister(bdi: disk->bdi);
535out_unregister_queue:
536 blk_unregister_queue(disk);
537 rq_qos_exit(disk->queue);
538out_put_slave_dir:
539 kobject_put(kobj: disk->slave_dir);
540 disk->slave_dir = NULL;
541out_put_holder_dir:
542 kobject_put(kobj: disk->part0->bd_holder_dir);
543out_del_block_link:
544 sysfs_remove_link(kobj: block_depr, name: dev_name(dev: ddev));
545out_device_del:
546 device_del(dev: ddev);
547out_free_ext_minor:
548 if (disk->major == BLOCK_EXT_MAJOR)
549 blk_free_ext_minor(minor: disk->first_minor);
550out_exit_elevator:
551 if (disk->queue->elevator)
552 elevator_exit(q: disk->queue);
553 return ret;
554}
555EXPORT_SYMBOL(device_add_disk);
556
557static void blk_report_disk_dead(struct gendisk *disk, bool surprise)
558{
559 struct block_device *bdev;
560 unsigned long idx;
561
562 /*
563 * On surprise disk removal, bdev_mark_dead() may call into file
564 * systems below. Make it clear that we're expecting to not hold
565 * disk->open_mutex.
566 */
567 lockdep_assert_not_held(&disk->open_mutex);
568
569 rcu_read_lock();
570 xa_for_each(&disk->part_tbl, idx, bdev) {
571 if (!kobject_get_unless_zero(kobj: &bdev->bd_device.kobj))
572 continue;
573 rcu_read_unlock();
574
575 bdev_mark_dead(bdev, surprise);
576
577 put_device(dev: &bdev->bd_device);
578 rcu_read_lock();
579 }
580 rcu_read_unlock();
581}
582
583static void __blk_mark_disk_dead(struct gendisk *disk)
584{
585 /*
586 * Fail any new I/O.
587 */
588 if (test_and_set_bit(GD_DEAD, addr: &disk->state))
589 return;
590
591 if (test_bit(GD_OWNS_QUEUE, &disk->state))
592 blk_queue_flag_set(QUEUE_FLAG_DYING, q: disk->queue);
593
594 /*
595 * Stop buffered writers from dirtying pages that can't be written out.
596 */
597 set_capacity(disk, 0);
598
599 /*
600 * Prevent new I/O from crossing bio_queue_enter().
601 */
602 blk_queue_start_drain(q: disk->queue);
603}
604
605/**
606 * blk_mark_disk_dead - mark a disk as dead
607 * @disk: disk to mark as dead
608 *
609 * Mark as disk as dead (e.g. surprise removed) and don't accept any new I/O
610 * to this disk.
611 */
612void blk_mark_disk_dead(struct gendisk *disk)
613{
614 __blk_mark_disk_dead(disk);
615 blk_report_disk_dead(disk, surprise: true);
616}
617EXPORT_SYMBOL_GPL(blk_mark_disk_dead);
618
619/**
620 * del_gendisk - remove the gendisk
621 * @disk: the struct gendisk to remove
622 *
623 * Removes the gendisk and all its associated resources. This deletes the
624 * partitions associated with the gendisk, and unregisters the associated
625 * request_queue.
626 *
627 * This is the counter to the respective __device_add_disk() call.
628 *
629 * The final removal of the struct gendisk happens when its refcount reaches 0
630 * with put_disk(), which should be called after del_gendisk(), if
631 * __device_add_disk() was used.
632 *
633 * Drivers exist which depend on the release of the gendisk to be synchronous,
634 * it should not be deferred.
635 *
636 * Context: can sleep
637 */
638void del_gendisk(struct gendisk *disk)
639{
640 struct request_queue *q = disk->queue;
641 struct block_device *part;
642 unsigned long idx;
643
644 might_sleep();
645
646 if (WARN_ON_ONCE(!disk_live(disk) && !(disk->flags & GENHD_FL_HIDDEN)))
647 return;
648
649 disk_del_events(disk);
650
651 /*
652 * Prevent new openers by unlinked the bdev inode.
653 */
654 mutex_lock(&disk->open_mutex);
655 xa_for_each(&disk->part_tbl, idx, part)
656 remove_inode_hash(inode: part->bd_inode);
657 mutex_unlock(lock: &disk->open_mutex);
658
659 /*
660 * Tell the file system to write back all dirty data and shut down if
661 * it hasn't been notified earlier.
662 */
663 if (!test_bit(GD_DEAD, &disk->state))
664 blk_report_disk_dead(disk, surprise: false);
665 __blk_mark_disk_dead(disk);
666
667 /*
668 * Drop all partitions now that the disk is marked dead.
669 */
670 mutex_lock(&disk->open_mutex);
671 xa_for_each_start(&disk->part_tbl, idx, part, 1)
672 drop_partition(part);
673 mutex_unlock(lock: &disk->open_mutex);
674
675 if (!(disk->flags & GENHD_FL_HIDDEN)) {
676 sysfs_remove_link(kobj: &disk_to_dev(disk)->kobj, name: "bdi");
677
678 /*
679 * Unregister bdi before releasing device numbers (as they can
680 * get reused and we'd get clashes in sysfs).
681 */
682 bdi_unregister(bdi: disk->bdi);
683 }
684
685 blk_unregister_queue(disk);
686
687 kobject_put(kobj: disk->part0->bd_holder_dir);
688 kobject_put(kobj: disk->slave_dir);
689 disk->slave_dir = NULL;
690
691 part_stat_set_all(part: disk->part0, value: 0);
692 disk->part0->bd_stamp = 0;
693 sysfs_remove_link(kobj: block_depr, name: dev_name(disk_to_dev(disk)));
694 pm_runtime_set_memalloc_noio(disk_to_dev(disk), enable: false);
695 device_del(disk_to_dev(disk));
696
697 blk_mq_freeze_queue_wait(q);
698
699 blk_throtl_cancel_bios(disk);
700
701 blk_sync_queue(q);
702 blk_flush_integrity();
703
704 if (queue_is_mq(q))
705 blk_mq_cancel_work_sync(q);
706
707 blk_mq_quiesce_queue(q);
708 if (q->elevator) {
709 mutex_lock(&q->sysfs_lock);
710 elevator_exit(q);
711 mutex_unlock(lock: &q->sysfs_lock);
712 }
713 rq_qos_exit(q);
714 blk_mq_unquiesce_queue(q);
715
716 /*
717 * If the disk does not own the queue, allow using passthrough requests
718 * again. Else leave the queue frozen to fail all I/O.
719 */
720 if (!test_bit(GD_OWNS_QUEUE, &disk->state)) {
721 blk_queue_flag_clear(QUEUE_FLAG_INIT_DONE, q);
722 __blk_mq_unfreeze_queue(q, force_atomic: true);
723 } else {
724 if (queue_is_mq(q))
725 blk_mq_exit_queue(q);
726 }
727}
728EXPORT_SYMBOL(del_gendisk);
729
730/**
731 * invalidate_disk - invalidate the disk
732 * @disk: the struct gendisk to invalidate
733 *
734 * A helper to invalidates the disk. It will clean the disk's associated
735 * buffer/page caches and reset its internal states so that the disk
736 * can be reused by the drivers.
737 *
738 * Context: can sleep
739 */
740void invalidate_disk(struct gendisk *disk)
741{
742 struct block_device *bdev = disk->part0;
743
744 invalidate_bdev(bdev);
745 bdev->bd_inode->i_mapping->wb_err = 0;
746 set_capacity(disk, 0);
747}
748EXPORT_SYMBOL(invalidate_disk);
749
750/* sysfs access to bad-blocks list. */
751static ssize_t disk_badblocks_show(struct device *dev,
752 struct device_attribute *attr,
753 char *page)
754{
755 struct gendisk *disk = dev_to_disk(dev);
756
757 if (!disk->bb)
758 return sprintf(buf: page, fmt: "\n");
759
760 return badblocks_show(bb: disk->bb, page, unack: 0);
761}
762
763static ssize_t disk_badblocks_store(struct device *dev,
764 struct device_attribute *attr,
765 const char *page, size_t len)
766{
767 struct gendisk *disk = dev_to_disk(dev);
768
769 if (!disk->bb)
770 return -ENXIO;
771
772 return badblocks_store(bb: disk->bb, page, len, unack: 0);
773}
774
775#ifdef CONFIG_BLOCK_LEGACY_AUTOLOAD
776void blk_request_module(dev_t devt)
777{
778 unsigned int major = MAJOR(devt);
779 struct blk_major_name **n;
780
781 mutex_lock(&major_names_lock);
782 for (n = &major_names[major_to_index(major)]; *n; n = &(*n)->next) {
783 if ((*n)->major == major && (*n)->probe) {
784 (*n)->probe(devt);
785 mutex_unlock(lock: &major_names_lock);
786 return;
787 }
788 }
789 mutex_unlock(lock: &major_names_lock);
790
791 if (request_module("block-major-%d-%d", MAJOR(devt), MINOR(devt)) > 0)
792 /* Make old-style 2.4 aliases work */
793 request_module("block-major-%d", MAJOR(devt));
794}
795#endif /* CONFIG_BLOCK_LEGACY_AUTOLOAD */
796
797#ifdef CONFIG_PROC_FS
798/* iterator */
799static void *disk_seqf_start(struct seq_file *seqf, loff_t *pos)
800{
801 loff_t skip = *pos;
802 struct class_dev_iter *iter;
803 struct device *dev;
804
805 iter = kmalloc(size: sizeof(*iter), GFP_KERNEL);
806 if (!iter)
807 return ERR_PTR(error: -ENOMEM);
808
809 seqf->private = iter;
810 class_dev_iter_init(iter, class: &block_class, NULL, type: &disk_type);
811 do {
812 dev = class_dev_iter_next(iter);
813 if (!dev)
814 return NULL;
815 } while (skip--);
816
817 return dev_to_disk(dev);
818}
819
820static void *disk_seqf_next(struct seq_file *seqf, void *v, loff_t *pos)
821{
822 struct device *dev;
823
824 (*pos)++;
825 dev = class_dev_iter_next(iter: seqf->private);
826 if (dev)
827 return dev_to_disk(dev);
828
829 return NULL;
830}
831
832static void disk_seqf_stop(struct seq_file *seqf, void *v)
833{
834 struct class_dev_iter *iter = seqf->private;
835
836 /* stop is called even after start failed :-( */
837 if (iter) {
838 class_dev_iter_exit(iter);
839 kfree(objp: iter);
840 seqf->private = NULL;
841 }
842}
843
844static void *show_partition_start(struct seq_file *seqf, loff_t *pos)
845{
846 void *p;
847
848 p = disk_seqf_start(seqf, pos);
849 if (!IS_ERR_OR_NULL(ptr: p) && !*pos)
850 seq_puts(m: seqf, s: "major minor #blocks name\n\n");
851 return p;
852}
853
854static int show_partition(struct seq_file *seqf, void *v)
855{
856 struct gendisk *sgp = v;
857 struct block_device *part;
858 unsigned long idx;
859
860 if (!get_capacity(disk: sgp) || (sgp->flags & GENHD_FL_HIDDEN))
861 return 0;
862
863 rcu_read_lock();
864 xa_for_each(&sgp->part_tbl, idx, part) {
865 if (!bdev_nr_sectors(bdev: part))
866 continue;
867 seq_printf(m: seqf, fmt: "%4d %7d %10llu %pg\n",
868 MAJOR(part->bd_dev), MINOR(part->bd_dev),
869 bdev_nr_sectors(bdev: part) >> 1, part);
870 }
871 rcu_read_unlock();
872 return 0;
873}
874
875static const struct seq_operations partitions_op = {
876 .start = show_partition_start,
877 .next = disk_seqf_next,
878 .stop = disk_seqf_stop,
879 .show = show_partition
880};
881#endif
882
883static int __init genhd_device_init(void)
884{
885 int error;
886
887 error = class_register(class: &block_class);
888 if (unlikely(error))
889 return error;
890 blk_dev_init();
891
892 register_blkdev(BLOCK_EXT_MAJOR, "blkext");
893
894 /* create top-level block dir */
895 block_depr = kobject_create_and_add(name: "block", NULL);
896 return 0;
897}
898
899subsys_initcall(genhd_device_init);
900
901static ssize_t disk_range_show(struct device *dev,
902 struct device_attribute *attr, char *buf)
903{
904 struct gendisk *disk = dev_to_disk(dev);
905
906 return sprintf(buf, fmt: "%d\n", disk->minors);
907}
908
909static ssize_t disk_ext_range_show(struct device *dev,
910 struct device_attribute *attr, char *buf)
911{
912 struct gendisk *disk = dev_to_disk(dev);
913
914 return sprintf(buf, fmt: "%d\n",
915 (disk->flags & GENHD_FL_NO_PART) ? 1 : DISK_MAX_PARTS);
916}
917
918static ssize_t disk_removable_show(struct device *dev,
919 struct device_attribute *attr, char *buf)
920{
921 struct gendisk *disk = dev_to_disk(dev);
922
923 return sprintf(buf, fmt: "%d\n",
924 (disk->flags & GENHD_FL_REMOVABLE ? 1 : 0));
925}
926
927static ssize_t disk_hidden_show(struct device *dev,
928 struct device_attribute *attr, char *buf)
929{
930 struct gendisk *disk = dev_to_disk(dev);
931
932 return sprintf(buf, fmt: "%d\n",
933 (disk->flags & GENHD_FL_HIDDEN ? 1 : 0));
934}
935
936static ssize_t disk_ro_show(struct device *dev,
937 struct device_attribute *attr, char *buf)
938{
939 struct gendisk *disk = dev_to_disk(dev);
940
941 return sprintf(buf, fmt: "%d\n", get_disk_ro(disk) ? 1 : 0);
942}
943
944ssize_t part_size_show(struct device *dev,
945 struct device_attribute *attr, char *buf)
946{
947 return sprintf(buf, fmt: "%llu\n", bdev_nr_sectors(dev_to_bdev(dev)));
948}
949
950ssize_t part_stat_show(struct device *dev,
951 struct device_attribute *attr, char *buf)
952{
953 struct block_device *bdev = dev_to_bdev(dev);
954 struct request_queue *q = bdev_get_queue(bdev);
955 struct disk_stats stat;
956 unsigned int inflight;
957
958 if (queue_is_mq(q))
959 inflight = blk_mq_in_flight(q, part: bdev);
960 else
961 inflight = part_in_flight(part: bdev);
962
963 if (inflight) {
964 part_stat_lock();
965 update_io_ticks(part: bdev, now: jiffies, end: true);
966 part_stat_unlock();
967 }
968 part_stat_read_all(part: bdev, stat: &stat);
969 return sprintf(buf,
970 fmt: "%8lu %8lu %8llu %8u "
971 "%8lu %8lu %8llu %8u "
972 "%8u %8u %8u "
973 "%8lu %8lu %8llu %8u "
974 "%8lu %8u"
975 "\n",
976 stat.ios[STAT_READ],
977 stat.merges[STAT_READ],
978 (unsigned long long)stat.sectors[STAT_READ],
979 (unsigned int)div_u64(dividend: stat.nsecs[STAT_READ], NSEC_PER_MSEC),
980 stat.ios[STAT_WRITE],
981 stat.merges[STAT_WRITE],
982 (unsigned long long)stat.sectors[STAT_WRITE],
983 (unsigned int)div_u64(dividend: stat.nsecs[STAT_WRITE], NSEC_PER_MSEC),
984 inflight,
985 jiffies_to_msecs(j: stat.io_ticks),
986 (unsigned int)div_u64(dividend: stat.nsecs[STAT_READ] +
987 stat.nsecs[STAT_WRITE] +
988 stat.nsecs[STAT_DISCARD] +
989 stat.nsecs[STAT_FLUSH],
990 NSEC_PER_MSEC),
991 stat.ios[STAT_DISCARD],
992 stat.merges[STAT_DISCARD],
993 (unsigned long long)stat.sectors[STAT_DISCARD],
994 (unsigned int)div_u64(dividend: stat.nsecs[STAT_DISCARD], NSEC_PER_MSEC),
995 stat.ios[STAT_FLUSH],
996 (unsigned int)div_u64(dividend: stat.nsecs[STAT_FLUSH], NSEC_PER_MSEC));
997}
998
999ssize_t part_inflight_show(struct device *dev, struct device_attribute *attr,
1000 char *buf)
1001{
1002 struct block_device *bdev = dev_to_bdev(dev);
1003 struct request_queue *q = bdev_get_queue(bdev);
1004 unsigned int inflight[2];
1005
1006 if (queue_is_mq(q))
1007 blk_mq_in_flight_rw(q, part: bdev, inflight);
1008 else
1009 part_in_flight_rw(part: bdev, inflight);
1010
1011 return sprintf(buf, fmt: "%8u %8u\n", inflight[0], inflight[1]);
1012}
1013
1014static ssize_t disk_capability_show(struct device *dev,
1015 struct device_attribute *attr, char *buf)
1016{
1017 dev_warn_once(dev, "the capability attribute has been deprecated.\n");
1018 return sprintf(buf, fmt: "0\n");
1019}
1020
1021static ssize_t disk_alignment_offset_show(struct device *dev,
1022 struct device_attribute *attr,
1023 char *buf)
1024{
1025 struct gendisk *disk = dev_to_disk(dev);
1026
1027 return sprintf(buf, fmt: "%d\n", bdev_alignment_offset(bdev: disk->part0));
1028}
1029
1030static ssize_t disk_discard_alignment_show(struct device *dev,
1031 struct device_attribute *attr,
1032 char *buf)
1033{
1034 struct gendisk *disk = dev_to_disk(dev);
1035
1036 return sprintf(buf, fmt: "%d\n", bdev_alignment_offset(bdev: disk->part0));
1037}
1038
1039static ssize_t diskseq_show(struct device *dev,
1040 struct device_attribute *attr, char *buf)
1041{
1042 struct gendisk *disk = dev_to_disk(dev);
1043
1044 return sprintf(buf, fmt: "%llu\n", disk->diskseq);
1045}
1046
1047static DEVICE_ATTR(range, 0444, disk_range_show, NULL);
1048static DEVICE_ATTR(ext_range, 0444, disk_ext_range_show, NULL);
1049static DEVICE_ATTR(removable, 0444, disk_removable_show, NULL);
1050static DEVICE_ATTR(hidden, 0444, disk_hidden_show, NULL);
1051static DEVICE_ATTR(ro, 0444, disk_ro_show, NULL);
1052static DEVICE_ATTR(size, 0444, part_size_show, NULL);
1053static DEVICE_ATTR(alignment_offset, 0444, disk_alignment_offset_show, NULL);
1054static DEVICE_ATTR(discard_alignment, 0444, disk_discard_alignment_show, NULL);
1055static DEVICE_ATTR(capability, 0444, disk_capability_show, NULL);
1056static DEVICE_ATTR(stat, 0444, part_stat_show, NULL);
1057static DEVICE_ATTR(inflight, 0444, part_inflight_show, NULL);
1058static DEVICE_ATTR(badblocks, 0644, disk_badblocks_show, disk_badblocks_store);
1059static DEVICE_ATTR(diskseq, 0444, diskseq_show, NULL);
1060
1061#ifdef CONFIG_FAIL_MAKE_REQUEST
1062ssize_t part_fail_show(struct device *dev,
1063 struct device_attribute *attr, char *buf)
1064{
1065 return sprintf(buf, fmt: "%d\n", dev_to_bdev(dev)->bd_make_it_fail);
1066}
1067
1068ssize_t part_fail_store(struct device *dev,
1069 struct device_attribute *attr,
1070 const char *buf, size_t count)
1071{
1072 int i;
1073
1074 if (count > 0 && sscanf(buf, "%d", &i) > 0)
1075 dev_to_bdev(dev)->bd_make_it_fail = i;
1076
1077 return count;
1078}
1079
1080static struct device_attribute dev_attr_fail =
1081 __ATTR(make-it-fail, 0644, part_fail_show, part_fail_store);
1082#endif /* CONFIG_FAIL_MAKE_REQUEST */
1083
1084#ifdef CONFIG_FAIL_IO_TIMEOUT
1085static struct device_attribute dev_attr_fail_timeout =
1086 __ATTR(io-timeout-fail, 0644, part_timeout_show, part_timeout_store);
1087#endif
1088
1089static struct attribute *disk_attrs[] = {
1090 &dev_attr_range.attr,
1091 &dev_attr_ext_range.attr,
1092 &dev_attr_removable.attr,
1093 &dev_attr_hidden.attr,
1094 &dev_attr_ro.attr,
1095 &dev_attr_size.attr,
1096 &dev_attr_alignment_offset.attr,
1097 &dev_attr_discard_alignment.attr,
1098 &dev_attr_capability.attr,
1099 &dev_attr_stat.attr,
1100 &dev_attr_inflight.attr,
1101 &dev_attr_badblocks.attr,
1102 &dev_attr_events.attr,
1103 &dev_attr_events_async.attr,
1104 &dev_attr_events_poll_msecs.attr,
1105 &dev_attr_diskseq.attr,
1106#ifdef CONFIG_FAIL_MAKE_REQUEST
1107 &dev_attr_fail.attr,
1108#endif
1109#ifdef CONFIG_FAIL_IO_TIMEOUT
1110 &dev_attr_fail_timeout.attr,
1111#endif
1112 NULL
1113};
1114
1115static umode_t disk_visible(struct kobject *kobj, struct attribute *a, int n)
1116{
1117 struct device *dev = container_of(kobj, typeof(*dev), kobj);
1118 struct gendisk *disk = dev_to_disk(dev);
1119
1120 if (a == &dev_attr_badblocks.attr && !disk->bb)
1121 return 0;
1122 return a->mode;
1123}
1124
1125static struct attribute_group disk_attr_group = {
1126 .attrs = disk_attrs,
1127 .is_visible = disk_visible,
1128};
1129
1130static const struct attribute_group *disk_attr_groups[] = {
1131 &disk_attr_group,
1132#ifdef CONFIG_BLK_DEV_IO_TRACE
1133 &blk_trace_attr_group,
1134#endif
1135#ifdef CONFIG_BLK_DEV_INTEGRITY
1136 &blk_integrity_attr_group,
1137#endif
1138 NULL
1139};
1140
1141/**
1142 * disk_release - releases all allocated resources of the gendisk
1143 * @dev: the device representing this disk
1144 *
1145 * This function releases all allocated resources of the gendisk.
1146 *
1147 * Drivers which used __device_add_disk() have a gendisk with a request_queue
1148 * assigned. Since the request_queue sits on top of the gendisk for these
1149 * drivers we also call blk_put_queue() for them, and we expect the
1150 * request_queue refcount to reach 0 at this point, and so the request_queue
1151 * will also be freed prior to the disk.
1152 *
1153 * Context: can sleep
1154 */
1155static void disk_release(struct device *dev)
1156{
1157 struct gendisk *disk = dev_to_disk(dev);
1158
1159 might_sleep();
1160 WARN_ON_ONCE(disk_live(disk));
1161
1162 blk_trace_remove(q: disk->queue);
1163
1164 /*
1165 * To undo the all initialization from blk_mq_init_allocated_queue in
1166 * case of a probe failure where add_disk is never called we have to
1167 * call blk_mq_exit_queue here. We can't do this for the more common
1168 * teardown case (yet) as the tagset can be gone by the time the disk
1169 * is released once it was added.
1170 */
1171 if (queue_is_mq(q: disk->queue) &&
1172 test_bit(GD_OWNS_QUEUE, &disk->state) &&
1173 !test_bit(GD_ADDED, &disk->state))
1174 blk_mq_exit_queue(q: disk->queue);
1175
1176 blkcg_exit_disk(disk);
1177
1178 bioset_exit(&disk->bio_split);
1179
1180 disk_release_events(disk);
1181 kfree(objp: disk->random);
1182 disk_free_zone_bitmaps(disk);
1183 xa_destroy(&disk->part_tbl);
1184
1185 disk->queue->disk = NULL;
1186 blk_put_queue(disk->queue);
1187
1188 if (test_bit(GD_ADDED, &disk->state) && disk->fops->free_disk)
1189 disk->fops->free_disk(disk);
1190
1191 iput(disk->part0->bd_inode); /* frees the disk */
1192}
1193
1194static int block_uevent(const struct device *dev, struct kobj_uevent_env *env)
1195{
1196 const struct gendisk *disk = dev_to_disk(dev);
1197
1198 return add_uevent_var(env, format: "DISKSEQ=%llu", disk->diskseq);
1199}
1200
1201struct class block_class = {
1202 .name = "block",
1203 .dev_uevent = block_uevent,
1204};
1205
1206static char *block_devnode(const struct device *dev, umode_t *mode,
1207 kuid_t *uid, kgid_t *gid)
1208{
1209 struct gendisk *disk = dev_to_disk(dev);
1210
1211 if (disk->fops->devnode)
1212 return disk->fops->devnode(disk, mode);
1213 return NULL;
1214}
1215
1216const struct device_type disk_type = {
1217 .name = "disk",
1218 .groups = disk_attr_groups,
1219 .release = disk_release,
1220 .devnode = block_devnode,
1221};
1222
1223#ifdef CONFIG_PROC_FS
1224/*
1225 * aggregate disk stat collector. Uses the same stats that the sysfs
1226 * entries do, above, but makes them available through one seq_file.
1227 *
1228 * The output looks suspiciously like /proc/partitions with a bunch of
1229 * extra fields.
1230 */
1231static int diskstats_show(struct seq_file *seqf, void *v)
1232{
1233 struct gendisk *gp = v;
1234 struct block_device *hd;
1235 unsigned int inflight;
1236 struct disk_stats stat;
1237 unsigned long idx;
1238
1239 /*
1240 if (&disk_to_dev(gp)->kobj.entry == block_class.devices.next)
1241 seq_puts(seqf, "major minor name"
1242 " rio rmerge rsect ruse wio wmerge "
1243 "wsect wuse running use aveq"
1244 "\n\n");
1245 */
1246
1247 rcu_read_lock();
1248 xa_for_each(&gp->part_tbl, idx, hd) {
1249 if (bdev_is_partition(bdev: hd) && !bdev_nr_sectors(bdev: hd))
1250 continue;
1251 if (queue_is_mq(q: gp->queue))
1252 inflight = blk_mq_in_flight(q: gp->queue, part: hd);
1253 else
1254 inflight = part_in_flight(part: hd);
1255
1256 if (inflight) {
1257 part_stat_lock();
1258 update_io_ticks(part: hd, now: jiffies, end: true);
1259 part_stat_unlock();
1260 }
1261 part_stat_read_all(part: hd, stat: &stat);
1262 seq_printf(m: seqf, fmt: "%4d %7d %pg "
1263 "%lu %lu %lu %u "
1264 "%lu %lu %lu %u "
1265 "%u %u %u "
1266 "%lu %lu %lu %u "
1267 "%lu %u"
1268 "\n",
1269 MAJOR(hd->bd_dev), MINOR(hd->bd_dev), hd,
1270 stat.ios[STAT_READ],
1271 stat.merges[STAT_READ],
1272 stat.sectors[STAT_READ],
1273 (unsigned int)div_u64(dividend: stat.nsecs[STAT_READ],
1274 NSEC_PER_MSEC),
1275 stat.ios[STAT_WRITE],
1276 stat.merges[STAT_WRITE],
1277 stat.sectors[STAT_WRITE],
1278 (unsigned int)div_u64(dividend: stat.nsecs[STAT_WRITE],
1279 NSEC_PER_MSEC),
1280 inflight,
1281 jiffies_to_msecs(j: stat.io_ticks),
1282 (unsigned int)div_u64(dividend: stat.nsecs[STAT_READ] +
1283 stat.nsecs[STAT_WRITE] +
1284 stat.nsecs[STAT_DISCARD] +
1285 stat.nsecs[STAT_FLUSH],
1286 NSEC_PER_MSEC),
1287 stat.ios[STAT_DISCARD],
1288 stat.merges[STAT_DISCARD],
1289 stat.sectors[STAT_DISCARD],
1290 (unsigned int)div_u64(dividend: stat.nsecs[STAT_DISCARD],
1291 NSEC_PER_MSEC),
1292 stat.ios[STAT_FLUSH],
1293 (unsigned int)div_u64(dividend: stat.nsecs[STAT_FLUSH],
1294 NSEC_PER_MSEC)
1295 );
1296 }
1297 rcu_read_unlock();
1298
1299 return 0;
1300}
1301
1302static const struct seq_operations diskstats_op = {
1303 .start = disk_seqf_start,
1304 .next = disk_seqf_next,
1305 .stop = disk_seqf_stop,
1306 .show = diskstats_show
1307};
1308
1309static int __init proc_genhd_init(void)
1310{
1311 proc_create_seq("diskstats", 0, NULL, &diskstats_op);
1312 proc_create_seq("partitions", 0, NULL, &partitions_op);
1313 return 0;
1314}
1315module_init(proc_genhd_init);
1316#endif /* CONFIG_PROC_FS */
1317
1318dev_t part_devt(struct gendisk *disk, u8 partno)
1319{
1320 struct block_device *part;
1321 dev_t devt = 0;
1322
1323 rcu_read_lock();
1324 part = xa_load(&disk->part_tbl, index: partno);
1325 if (part)
1326 devt = part->bd_dev;
1327 rcu_read_unlock();
1328
1329 return devt;
1330}
1331
1332struct gendisk *__alloc_disk_node(struct request_queue *q, int node_id,
1333 struct lock_class_key *lkclass)
1334{
1335 struct gendisk *disk;
1336
1337 disk = kzalloc_node(size: sizeof(struct gendisk), GFP_KERNEL, node: node_id);
1338 if (!disk)
1339 return NULL;
1340
1341 if (bioset_init(&disk->bio_split, BIO_POOL_SIZE, 0, flags: 0))
1342 goto out_free_disk;
1343
1344 disk->bdi = bdi_alloc(node_id);
1345 if (!disk->bdi)
1346 goto out_free_bioset;
1347
1348 /* bdev_alloc() might need the queue, set before the first call */
1349 disk->queue = q;
1350
1351 disk->part0 = bdev_alloc(disk, partno: 0);
1352 if (!disk->part0)
1353 goto out_free_bdi;
1354
1355 disk->node_id = node_id;
1356 mutex_init(&disk->open_mutex);
1357 xa_init(xa: &disk->part_tbl);
1358 if (xa_insert(xa: &disk->part_tbl, index: 0, entry: disk->part0, GFP_KERNEL))
1359 goto out_destroy_part_tbl;
1360
1361 if (blkcg_init_disk(disk))
1362 goto out_erase_part0;
1363
1364 rand_initialize_disk(disk);
1365 disk_to_dev(disk)->class = &block_class;
1366 disk_to_dev(disk)->type = &disk_type;
1367 device_initialize(disk_to_dev(disk));
1368 inc_diskseq(disk);
1369 q->disk = disk;
1370 lockdep_init_map(lock: &disk->lockdep_map, name: "(bio completion)", key: lkclass, subclass: 0);
1371#ifdef CONFIG_BLOCK_HOLDER_DEPRECATED
1372 INIT_LIST_HEAD(list: &disk->slave_bdevs);
1373#endif
1374 return disk;
1375
1376out_erase_part0:
1377 xa_erase(&disk->part_tbl, index: 0);
1378out_destroy_part_tbl:
1379 xa_destroy(&disk->part_tbl);
1380 disk->part0->bd_disk = NULL;
1381 iput(disk->part0->bd_inode);
1382out_free_bdi:
1383 bdi_put(bdi: disk->bdi);
1384out_free_bioset:
1385 bioset_exit(&disk->bio_split);
1386out_free_disk:
1387 kfree(objp: disk);
1388 return NULL;
1389}
1390
1391struct gendisk *__blk_alloc_disk(int node, struct lock_class_key *lkclass)
1392{
1393 struct request_queue *q;
1394 struct gendisk *disk;
1395
1396 q = blk_alloc_queue(node_id: node);
1397 if (!q)
1398 return NULL;
1399
1400 disk = __alloc_disk_node(q, node_id: node, lkclass);
1401 if (!disk) {
1402 blk_put_queue(q);
1403 return NULL;
1404 }
1405 set_bit(GD_OWNS_QUEUE, addr: &disk->state);
1406 return disk;
1407}
1408EXPORT_SYMBOL(__blk_alloc_disk);
1409
1410/**
1411 * put_disk - decrements the gendisk refcount
1412 * @disk: the struct gendisk to decrement the refcount for
1413 *
1414 * This decrements the refcount for the struct gendisk. When this reaches 0
1415 * we'll have disk_release() called.
1416 *
1417 * Note: for blk-mq disk put_disk must be called before freeing the tag_set
1418 * when handling probe errors (that is before add_disk() is called).
1419 *
1420 * Context: Any context, but the last reference must not be dropped from
1421 * atomic context.
1422 */
1423void put_disk(struct gendisk *disk)
1424{
1425 if (disk)
1426 put_device(disk_to_dev(disk));
1427}
1428EXPORT_SYMBOL(put_disk);
1429
1430static void set_disk_ro_uevent(struct gendisk *gd, int ro)
1431{
1432 char event[] = "DISK_RO=1";
1433 char *envp[] = { event, NULL };
1434
1435 if (!ro)
1436 event[8] = '0';
1437 kobject_uevent_env(kobj: &disk_to_dev(gd)->kobj, action: KOBJ_CHANGE, envp);
1438}
1439
1440/**
1441 * set_disk_ro - set a gendisk read-only
1442 * @disk: gendisk to operate on
1443 * @read_only: %true to set the disk read-only, %false set the disk read/write
1444 *
1445 * This function is used to indicate whether a given disk device should have its
1446 * read-only flag set. set_disk_ro() is typically used by device drivers to
1447 * indicate whether the underlying physical device is write-protected.
1448 */
1449void set_disk_ro(struct gendisk *disk, bool read_only)
1450{
1451 if (read_only) {
1452 if (test_and_set_bit(GD_READ_ONLY, addr: &disk->state))
1453 return;
1454 } else {
1455 if (!test_and_clear_bit(GD_READ_ONLY, addr: &disk->state))
1456 return;
1457 }
1458 set_disk_ro_uevent(gd: disk, ro: read_only);
1459}
1460EXPORT_SYMBOL(set_disk_ro);
1461
1462void inc_diskseq(struct gendisk *disk)
1463{
1464 disk->diskseq = atomic64_inc_return(v: &diskseq);
1465}
1466

source code of linux/block/genhd.c