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1/*
2 * gendisk handling
3 */
4
5#include <linux/module.h>
6#include <linux/fs.h>
7#include <linux/genhd.h>
8#include <linux/kdev_t.h>
9#include <linux/kernel.h>
10#include <linux/blkdev.h>
11#include <linux/backing-dev.h>
12#include <linux/init.h>
13#include <linux/spinlock.h>
14#include <linux/proc_fs.h>
15#include <linux/seq_file.h>
16#include <linux/slab.h>
17#include <linux/kmod.h>
18#include <linux/kobj_map.h>
19#include <linux/mutex.h>
20#include <linux/idr.h>
21#include <linux/log2.h>
22#include <linux/pm_runtime.h>
23#include <linux/badblocks.h>
24
25#include "blk.h"
26
27static DEFINE_MUTEX(block_class_lock);
28struct kobject *block_depr;
29
30/* for extended dynamic devt allocation, currently only one major is used */
31#define NR_EXT_DEVT (1 << MINORBITS)
32
33/* For extended devt allocation. ext_devt_lock prevents look up
34 * results from going away underneath its user.
35 */
36static DEFINE_SPINLOCK(ext_devt_lock);
37static DEFINE_IDR(ext_devt_idr);
38
39static struct device_type disk_type;
40
41static void disk_check_events(struct disk_events *ev,
42 unsigned int *clearing_ptr);
43static void disk_alloc_events(struct gendisk *disk);
44static void disk_add_events(struct gendisk *disk);
45static void disk_del_events(struct gendisk *disk);
46static void disk_release_events(struct gendisk *disk);
47
48/**
49 * disk_get_part - get partition
50 * @disk: disk to look partition from
51 * @partno: partition number
52 *
53 * Look for partition @partno from @disk. If found, increment
54 * reference count and return it.
55 *
56 * CONTEXT:
57 * Don't care.
58 *
59 * RETURNS:
60 * Pointer to the found partition on success, NULL if not found.
61 */
62struct hd_struct *disk_get_part(struct gendisk *disk, int partno)
63{
64 struct hd_struct *part = NULL;
65 struct disk_part_tbl *ptbl;
66
67 if (unlikely(partno < 0))
68 return NULL;
69
70 rcu_read_lock();
71
72 ptbl = rcu_dereference(disk->part_tbl);
73 if (likely(partno < ptbl->len)) {
74 part = rcu_dereference(ptbl->part[partno]);
75 if (part)
76 get_device(part_to_dev(part));
77 }
78
79 rcu_read_unlock();
80
81 return part;
82}
83EXPORT_SYMBOL_GPL(disk_get_part);
84
85/**
86 * disk_part_iter_init - initialize partition iterator
87 * @piter: iterator to initialize
88 * @disk: disk to iterate over
89 * @flags: DISK_PITER_* flags
90 *
91 * Initialize @piter so that it iterates over partitions of @disk.
92 *
93 * CONTEXT:
94 * Don't care.
95 */
96void disk_part_iter_init(struct disk_part_iter *piter, struct gendisk *disk,
97 unsigned int flags)
98{
99 struct disk_part_tbl *ptbl;
100
101 rcu_read_lock();
102 ptbl = rcu_dereference(disk->part_tbl);
103
104 piter->disk = disk;
105 piter->part = NULL;
106
107 if (flags & DISK_PITER_REVERSE)
108 piter->idx = ptbl->len - 1;
109 else if (flags & (DISK_PITER_INCL_PART0 | DISK_PITER_INCL_EMPTY_PART0))
110 piter->idx = 0;
111 else
112 piter->idx = 1;
113
114 piter->flags = flags;
115
116 rcu_read_unlock();
117}
118EXPORT_SYMBOL_GPL(disk_part_iter_init);
119
120/**
121 * disk_part_iter_next - proceed iterator to the next partition and return it
122 * @piter: iterator of interest
123 *
124 * Proceed @piter to the next partition and return it.
125 *
126 * CONTEXT:
127 * Don't care.
128 */
129struct hd_struct *disk_part_iter_next(struct disk_part_iter *piter)
130{
131 struct disk_part_tbl *ptbl;
132 int inc, end;
133
134 /* put the last partition */
135 disk_put_part(piter->part);
136 piter->part = NULL;
137
138 /* get part_tbl */
139 rcu_read_lock();
140 ptbl = rcu_dereference(piter->disk->part_tbl);
141
142 /* determine iteration parameters */
143 if (piter->flags & DISK_PITER_REVERSE) {
144 inc = -1;
145 if (piter->flags & (DISK_PITER_INCL_PART0 |
146 DISK_PITER_INCL_EMPTY_PART0))
147 end = -1;
148 else
149 end = 0;
150 } else {
151 inc = 1;
152 end = ptbl->len;
153 }
154
155 /* iterate to the next partition */
156 for (; piter->idx != end; piter->idx += inc) {
157 struct hd_struct *part;
158
159 part = rcu_dereference(ptbl->part[piter->idx]);
160 if (!part)
161 continue;
162 if (!part_nr_sects_read(part) &&
163 !(piter->flags & DISK_PITER_INCL_EMPTY) &&
164 !(piter->flags & DISK_PITER_INCL_EMPTY_PART0 &&
165 piter->idx == 0))
166 continue;
167
168 get_device(part_to_dev(part));
169 piter->part = part;
170 piter->idx += inc;
171 break;
172 }
173
174 rcu_read_unlock();
175
176 return piter->part;
177}
178EXPORT_SYMBOL_GPL(disk_part_iter_next);
179
180/**
181 * disk_part_iter_exit - finish up partition iteration
182 * @piter: iter of interest
183 *
184 * Called when iteration is over. Cleans up @piter.
185 *
186 * CONTEXT:
187 * Don't care.
188 */
189void disk_part_iter_exit(struct disk_part_iter *piter)
190{
191 disk_put_part(piter->part);
192 piter->part = NULL;
193}
194EXPORT_SYMBOL_GPL(disk_part_iter_exit);
195
196static inline int sector_in_part(struct hd_struct *part, sector_t sector)
197{
198 return part->start_sect <= sector &&
199 sector < part->start_sect + part_nr_sects_read(part);
200}
201
202/**
203 * disk_map_sector_rcu - map sector to partition
204 * @disk: gendisk of interest
205 * @sector: sector to map
206 *
207 * Find out which partition @sector maps to on @disk. This is
208 * primarily used for stats accounting.
209 *
210 * CONTEXT:
211 * RCU read locked. The returned partition pointer is valid only
212 * while preemption is disabled.
213 *
214 * RETURNS:
215 * Found partition on success, part0 is returned if no partition matches
216 */
217struct hd_struct *disk_map_sector_rcu(struct gendisk *disk, sector_t sector)
218{
219 struct disk_part_tbl *ptbl;
220 struct hd_struct *part;
221 int i;
222
223 ptbl = rcu_dereference(disk->part_tbl);
224
225 part = rcu_dereference(ptbl->last_lookup);
226 if (part && sector_in_part(part, sector))
227 return part;
228
229 for (i = 1; i < ptbl->len; i++) {
230 part = rcu_dereference(ptbl->part[i]);
231
232 if (part && sector_in_part(part, sector)) {
233 rcu_assign_pointer(ptbl->last_lookup, part);
234 return part;
235 }
236 }
237 return &disk->part0;
238}
239EXPORT_SYMBOL_GPL(disk_map_sector_rcu);
240
241/*
242 * Can be deleted altogether. Later.
243 *
244 */
245static struct blk_major_name {
246 struct blk_major_name *next;
247 int major;
248 char name[16];
249} *major_names[BLKDEV_MAJOR_HASH_SIZE];
250
251/* index in the above - for now: assume no multimajor ranges */
252static inline int major_to_index(unsigned major)
253{
254 return major % BLKDEV_MAJOR_HASH_SIZE;
255}
256
257#ifdef CONFIG_PROC_FS
258void blkdev_show(struct seq_file *seqf, off_t offset)
259{
260 struct blk_major_name *dp;
261
262 if (offset < BLKDEV_MAJOR_HASH_SIZE) {
263 mutex_lock(&block_class_lock);
264 for (dp = major_names[offset]; dp; dp = dp->next)
265 seq_printf(seqf, "%3d %s\n", dp->major, dp->name);
266 mutex_unlock(&block_class_lock);
267 }
268}
269#endif /* CONFIG_PROC_FS */
270
271/**
272 * register_blkdev - register a new block device
273 *
274 * @major: the requested major device number [1..255]. If @major=0, try to
275 * allocate any unused major number.
276 * @name: the name of the new block device as a zero terminated string
277 *
278 * The @name must be unique within the system.
279 *
280 * The return value depends on the @major input parameter.
281 * - if a major device number was requested in range [1..255] then the
282 * function returns zero on success, or a negative error code
283 * - if any unused major number was requested with @major=0 parameter
284 * then the return value is the allocated major number in range
285 * [1..255] or a negative error code otherwise
286 */
287int register_blkdev(unsigned int major, const char *name)
288{
289 struct blk_major_name **n, *p;
290 int index, ret = 0;
291
292 mutex_lock(&block_class_lock);
293
294 /* temporary */
295 if (major == 0) {
296 for (index = ARRAY_SIZE(major_names)-1; index > 0; index--) {
297 if (major_names[index] == NULL)
298 break;
299 }
300
301 if (index == 0) {
302 printk("register_blkdev: failed to get major for %s\n",
303 name);
304 ret = -EBUSY;
305 goto out;
306 }
307 major = index;
308 ret = major;
309 }
310
311 p = kmalloc(sizeof(struct blk_major_name), GFP_KERNEL);
312 if (p == NULL) {
313 ret = -ENOMEM;
314 goto out;
315 }
316
317 p->major = major;
318 strlcpy(p->name, name, sizeof(p->name));
319 p->next = NULL;
320 index = major_to_index(major);
321
322 for (n = &major_names[index]; *n; n = &(*n)->next) {
323 if ((*n)->major == major)
324 break;
325 }
326 if (!*n)
327 *n = p;
328 else
329 ret = -EBUSY;
330
331 if (ret < 0) {
332 printk("register_blkdev: cannot get major %d for %s\n",
333 major, name);
334 kfree(p);
335 }
336out:
337 mutex_unlock(&block_class_lock);
338 return ret;
339}
340
341EXPORT_SYMBOL(register_blkdev);
342
343void unregister_blkdev(unsigned int major, const char *name)
344{
345 struct blk_major_name **n;
346 struct blk_major_name *p = NULL;
347 int index = major_to_index(major);
348
349 mutex_lock(&block_class_lock);
350 for (n = &major_names[index]; *n; n = &(*n)->next)
351 if ((*n)->major == major)
352 break;
353 if (!*n || strcmp((*n)->name, name)) {
354 WARN_ON(1);
355 } else {
356 p = *n;
357 *n = p->next;
358 }
359 mutex_unlock(&block_class_lock);
360 kfree(p);
361}
362
363EXPORT_SYMBOL(unregister_blkdev);
364
365static struct kobj_map *bdev_map;
366
367/**
368 * blk_mangle_minor - scatter minor numbers apart
369 * @minor: minor number to mangle
370 *
371 * Scatter consecutively allocated @minor number apart if MANGLE_DEVT
372 * is enabled. Mangling twice gives the original value.
373 *
374 * RETURNS:
375 * Mangled value.
376 *
377 * CONTEXT:
378 * Don't care.
379 */
380static int blk_mangle_minor(int minor)
381{
382#ifdef CONFIG_DEBUG_BLOCK_EXT_DEVT
383 int i;
384
385 for (i = 0; i < MINORBITS / 2; i++) {
386 int low = minor & (1 << i);
387 int high = minor & (1 << (MINORBITS - 1 - i));
388 int distance = MINORBITS - 1 - 2 * i;
389
390 minor ^= low | high; /* clear both bits */
391 low <<= distance; /* swap the positions */
392 high >>= distance;
393 minor |= low | high; /* and set */
394 }
395#endif
396 return minor;
397}
398
399/**
400 * blk_alloc_devt - allocate a dev_t for a partition
401 * @part: partition to allocate dev_t for
402 * @devt: out parameter for resulting dev_t
403 *
404 * Allocate a dev_t for block device.
405 *
406 * RETURNS:
407 * 0 on success, allocated dev_t is returned in *@devt. -errno on
408 * failure.
409 *
410 * CONTEXT:
411 * Might sleep.
412 */
413int blk_alloc_devt(struct hd_struct *part, dev_t *devt)
414{
415 struct gendisk *disk = part_to_disk(part);
416 int idx;
417
418 /* in consecutive minor range? */
419 if (part->partno < disk->minors) {
420 *devt = MKDEV(disk->major, disk->first_minor + part->partno);
421 return 0;
422 }
423
424 /* allocate ext devt */
425 idr_preload(GFP_KERNEL);
426
427 spin_lock_bh(&ext_devt_lock);
428 idx = idr_alloc(&ext_devt_idr, part, 0, NR_EXT_DEVT, GFP_NOWAIT);
429 spin_unlock_bh(&ext_devt_lock);
430
431 idr_preload_end();
432 if (idx < 0)
433 return idx == -ENOSPC ? -EBUSY : idx;
434
435 *devt = MKDEV(BLOCK_EXT_MAJOR, blk_mangle_minor(idx));
436 return 0;
437}
438
439/**
440 * blk_free_devt - free a dev_t
441 * @devt: dev_t to free
442 *
443 * Free @devt which was allocated using blk_alloc_devt().
444 *
445 * CONTEXT:
446 * Might sleep.
447 */
448void blk_free_devt(dev_t devt)
449{
450 if (devt == MKDEV(0, 0))
451 return;
452
453 if (MAJOR(devt) == BLOCK_EXT_MAJOR) {
454 spin_lock_bh(&ext_devt_lock);
455 idr_remove(&ext_devt_idr, blk_mangle_minor(MINOR(devt)));
456 spin_unlock_bh(&ext_devt_lock);
457 }
458}
459
460static char *bdevt_str(dev_t devt, char *buf)
461{
462 if (MAJOR(devt) <= 0xff && MINOR(devt) <= 0xff) {
463 char tbuf[BDEVT_SIZE];
464 snprintf(tbuf, BDEVT_SIZE, "%02x%02x", MAJOR(devt), MINOR(devt));
465 snprintf(buf, BDEVT_SIZE, "%-9s", tbuf);
466 } else
467 snprintf(buf, BDEVT_SIZE, "%03x:%05x", MAJOR(devt), MINOR(devt));
468
469 return buf;
470}
471
472/*
473 * Register device numbers dev..(dev+range-1)
474 * range must be nonzero
475 * The hash chain is sorted on range, so that subranges can override.
476 */
477void blk_register_region(dev_t devt, unsigned long range, struct module *module,
478 struct kobject *(*probe)(dev_t, int *, void *),
479 int (*lock)(dev_t, void *), void *data)
480{
481 kobj_map(bdev_map, devt, range, module, probe, lock, data);
482}
483
484EXPORT_SYMBOL(blk_register_region);
485
486void blk_unregister_region(dev_t devt, unsigned long range)
487{
488 kobj_unmap(bdev_map, devt, range);
489}
490
491EXPORT_SYMBOL(blk_unregister_region);
492
493static struct kobject *exact_match(dev_t devt, int *partno, void *data)
494{
495 struct gendisk *p = data;
496
497 return &disk_to_dev(p)->kobj;
498}
499
500static int exact_lock(dev_t devt, void *data)
501{
502 struct gendisk *p = data;
503
504 if (!get_disk(p))
505 return -1;
506 return 0;
507}
508
509static void register_disk(struct gendisk *disk)
510{
511 struct device *ddev = disk_to_dev(disk);
512 struct block_device *bdev;
513 struct disk_part_iter piter;
514 struct hd_struct *part;
515 int err;
516
517 ddev->parent = disk->driverfs_dev;
518
519 dev_set_name(ddev, "%s", disk->disk_name);
520
521 /* delay uevents, until we scanned partition table */
522 dev_set_uevent_suppress(ddev, 1);
523
524 if (device_add(ddev))
525 return;
526 if (!sysfs_deprecated) {
527 err = sysfs_create_link(block_depr, &ddev->kobj,
528 kobject_name(&ddev->kobj));
529 if (err) {
530 device_del(ddev);
531 return;
532 }
533 }
534
535 /*
536 * avoid probable deadlock caused by allocating memory with
537 * GFP_KERNEL in runtime_resume callback of its all ancestor
538 * devices
539 */
540 pm_runtime_set_memalloc_noio(ddev, true);
541
542 disk->part0.holder_dir = kobject_create_and_add("holders", &ddev->kobj);
543 disk->slave_dir = kobject_create_and_add("slaves", &ddev->kobj);
544
545 /* No minors to use for partitions */
546 if (!disk_part_scan_enabled(disk))
547 goto exit;
548
549 /* No such device (e.g., media were just removed) */
550 if (!get_capacity(disk))
551 goto exit;
552
553 bdev = bdget_disk(disk, 0);
554 if (!bdev)
555 goto exit;
556
557 bdev->bd_invalidated = 1;
558 err = blkdev_get(bdev, FMODE_READ, NULL);
559 if (err < 0)
560 goto exit;
561 blkdev_put(bdev, FMODE_READ);
562
563exit:
564 /* announce disk after possible partitions are created */
565 dev_set_uevent_suppress(ddev, 0);
566 kobject_uevent(&ddev->kobj, KOBJ_ADD);
567
568 /* announce possible partitions */
569 disk_part_iter_init(&piter, disk, 0);
570 while ((part = disk_part_iter_next(&piter)))
571 kobject_uevent(&part_to_dev(part)->kobj, KOBJ_ADD);
572 disk_part_iter_exit(&piter);
573}
574
575/**
576 * add_disk - add partitioning information to kernel list
577 * @disk: per-device partitioning information
578 *
579 * This function registers the partitioning information in @disk
580 * with the kernel.
581 *
582 * FIXME: error handling
583 */
584void add_disk(struct gendisk *disk)
585{
586 struct backing_dev_info *bdi;
587 dev_t devt;
588 int retval;
589
590 /* minors == 0 indicates to use ext devt from part0 and should
591 * be accompanied with EXT_DEVT flag. Make sure all
592 * parameters make sense.
593 */
594 WARN_ON(disk->minors && !(disk->major || disk->first_minor));
595 WARN_ON(!disk->minors && !(disk->flags & GENHD_FL_EXT_DEVT));
596
597 disk->flags |= GENHD_FL_UP;
598
599 retval = blk_alloc_devt(&disk->part0, &devt);
600 if (retval) {
601 WARN_ON(1);
602 return;
603 }
604 disk_to_dev(disk)->devt = devt;
605
606 /* ->major and ->first_minor aren't supposed to be
607 * dereferenced from here on, but set them just in case.
608 */
609 disk->major = MAJOR(devt);
610 disk->first_minor = MINOR(devt);
611
612 disk_alloc_events(disk);
613
614 /* Register BDI before referencing it from bdev */
615 bdi = &disk->queue->backing_dev_info;
616 bdi_register_dev(bdi, disk_devt(disk));
617
618 blk_register_region(disk_devt(disk), disk->minors, NULL,
619 exact_match, exact_lock, disk);
620 register_disk(disk);
621 blk_register_queue(disk);
622
623 /*
624 * Take an extra ref on queue which will be put on disk_release()
625 * so that it sticks around as long as @disk is there.
626 */
627 WARN_ON_ONCE(!blk_get_queue(disk->queue));
628
629 retval = sysfs_create_link(&disk_to_dev(disk)->kobj, &bdi->dev->kobj,
630 "bdi");
631 WARN_ON(retval);
632
633 disk_add_events(disk);
634 blk_integrity_add(disk);
635}
636EXPORT_SYMBOL(add_disk);
637
638void del_gendisk(struct gendisk *disk)
639{
640 struct disk_part_iter piter;
641 struct hd_struct *part;
642
643 blk_integrity_del(disk);
644 disk_del_events(disk);
645
646 /* invalidate stuff */
647 disk_part_iter_init(&piter, disk,
648 DISK_PITER_INCL_EMPTY | DISK_PITER_REVERSE);
649 while ((part = disk_part_iter_next(&piter))) {
650 invalidate_partition(disk, part->partno);
651 delete_partition(disk, part->partno);
652 }
653 disk_part_iter_exit(&piter);
654
655 invalidate_partition(disk, 0);
656 set_capacity(disk, 0);
657 disk->flags &= ~GENHD_FL_UP;
658
659 sysfs_remove_link(&disk_to_dev(disk)->kobj, "bdi");
660 blk_unregister_queue(disk);
661 blk_unregister_region(disk_devt(disk), disk->minors);
662
663 part_stat_set_all(&disk->part0, 0);
664 disk->part0.stamp = 0;
665
666 kobject_put(disk->part0.holder_dir);
667 kobject_put(disk->slave_dir);
668 if (!sysfs_deprecated)
669 sysfs_remove_link(block_depr, dev_name(disk_to_dev(disk)));
670 pm_runtime_set_memalloc_noio(disk_to_dev(disk), false);
671 device_del(disk_to_dev(disk));
672}
673EXPORT_SYMBOL(del_gendisk);
674
675/* sysfs access to bad-blocks list. */
676static ssize_t disk_badblocks_show(struct device *dev,
677 struct device_attribute *attr,
678 char *page)
679{
680 struct gendisk *disk = dev_to_disk(dev);
681
682 if (!disk->bb)
683 return sprintf(page, "\n");
684
685 return badblocks_show(disk->bb, page, 0);
686}
687
688static ssize_t disk_badblocks_store(struct device *dev,
689 struct device_attribute *attr,
690 const char *page, size_t len)
691{
692 struct gendisk *disk = dev_to_disk(dev);
693
694 if (!disk->bb)
695 return -ENXIO;
696
697 return badblocks_store(disk->bb, page, len, 0);
698}
699
700/**
701 * get_gendisk - get partitioning information for a given device
702 * @devt: device to get partitioning information for
703 * @partno: returned partition index
704 *
705 * This function gets the structure containing partitioning
706 * information for the given device @devt.
707 */
708struct gendisk *get_gendisk(dev_t devt, int *partno)
709{
710 struct gendisk *disk = NULL;
711
712 if (MAJOR(devt) != BLOCK_EXT_MAJOR) {
713 struct kobject *kobj;
714
715 kobj = kobj_lookup(bdev_map, devt, partno);
716 if (kobj)
717 disk = dev_to_disk(kobj_to_dev(kobj));
718 } else {
719 struct hd_struct *part;
720
721 spin_lock_bh(&ext_devt_lock);
722 part = idr_find(&ext_devt_idr, blk_mangle_minor(MINOR(devt)));
723 if (part && get_disk(part_to_disk(part))) {
724 *partno = part->partno;
725 disk = part_to_disk(part);
726 }
727 spin_unlock_bh(&ext_devt_lock);
728 }
729
730 return disk;
731}
732EXPORT_SYMBOL(get_gendisk);
733
734/**
735 * bdget_disk - do bdget() by gendisk and partition number
736 * @disk: gendisk of interest
737 * @partno: partition number
738 *
739 * Find partition @partno from @disk, do bdget() on it.
740 *
741 * CONTEXT:
742 * Don't care.
743 *
744 * RETURNS:
745 * Resulting block_device on success, NULL on failure.
746 */
747struct block_device *bdget_disk(struct gendisk *disk, int partno)
748{
749 struct hd_struct *part;
750 struct block_device *bdev = NULL;
751
752 part = disk_get_part(disk, partno);
753 if (part)
754 bdev = bdget(part_devt(part));
755 disk_put_part(part);
756
757 return bdev;
758}
759EXPORT_SYMBOL(bdget_disk);
760
761/*
762 * print a full list of all partitions - intended for places where the root
763 * filesystem can't be mounted and thus to give the victim some idea of what
764 * went wrong
765 */
766void __init printk_all_partitions(void)
767{
768 struct class_dev_iter iter;
769 struct device *dev;
770
771 class_dev_iter_init(&iter, &block_class, NULL, &disk_type);
772 while ((dev = class_dev_iter_next(&iter))) {
773 struct gendisk *disk = dev_to_disk(dev);
774 struct disk_part_iter piter;
775 struct hd_struct *part;
776 char name_buf[BDEVNAME_SIZE];
777 char devt_buf[BDEVT_SIZE];
778
779 /*
780 * Don't show empty devices or things that have been
781 * suppressed
782 */
783 if (get_capacity(disk) == 0 ||
784 (disk->flags & GENHD_FL_SUPPRESS_PARTITION_INFO))
785 continue;
786
787 /*
788 * Note, unlike /proc/partitions, I am showing the
789 * numbers in hex - the same format as the root=
790 * option takes.
791 */
792 disk_part_iter_init(&piter, disk, DISK_PITER_INCL_PART0);
793 while ((part = disk_part_iter_next(&piter))) {
794 bool is_part0 = part == &disk->part0;
795
796 printk("%s%s %10llu %s %s", is_part0 ? "" : " ",
797 bdevt_str(part_devt(part), devt_buf),
798 (unsigned long long)part_nr_sects_read(part) >> 1
799 , disk_name(disk, part->partno, name_buf),
800 part->info ? part->info->uuid : "");
801 if (is_part0) {
802 if (disk->driverfs_dev != NULL &&
803 disk->driverfs_dev->driver != NULL)
804 printk(" driver: %s\n",
805 disk->driverfs_dev->driver->name);
806 else
807 printk(" (driver?)\n");
808 } else
809 printk("\n");
810 }
811 disk_part_iter_exit(&piter);
812 }
813 class_dev_iter_exit(&iter);
814}
815
816#ifdef CONFIG_PROC_FS
817/* iterator */
818static void *disk_seqf_start(struct seq_file *seqf, loff_t *pos)
819{
820 loff_t skip = *pos;
821 struct class_dev_iter *iter;
822 struct device *dev;
823
824 iter = kmalloc(sizeof(*iter), GFP_KERNEL);
825 if (!iter)
826 return ERR_PTR(-ENOMEM);
827
828 seqf->private = iter;
829 class_dev_iter_init(iter, &block_class, NULL, &disk_type);
830 do {
831 dev = class_dev_iter_next(iter);
832 if (!dev)
833 return NULL;
834 } while (skip--);
835
836 return dev_to_disk(dev);
837}
838
839static void *disk_seqf_next(struct seq_file *seqf, void *v, loff_t *pos)
840{
841 struct device *dev;
842
843 (*pos)++;
844 dev = class_dev_iter_next(seqf->private);
845 if (dev)
846 return dev_to_disk(dev);
847
848 return NULL;
849}
850
851static void disk_seqf_stop(struct seq_file *seqf, void *v)
852{
853 struct class_dev_iter *iter = seqf->private;
854
855 /* stop is called even after start failed :-( */
856 if (iter) {
857 class_dev_iter_exit(iter);
858 kfree(iter);
859 }
860}
861
862static void *show_partition_start(struct seq_file *seqf, loff_t *pos)
863{
864 void *p;
865
866 p = disk_seqf_start(seqf, pos);
867 if (!IS_ERR_OR_NULL(p) && !*pos)
868 seq_puts(seqf, "major minor #blocks name\n\n");
869 return p;
870}
871
872static int show_partition(struct seq_file *seqf, void *v)
873{
874 struct gendisk *sgp = v;
875 struct disk_part_iter piter;
876 struct hd_struct *part;
877 char buf[BDEVNAME_SIZE];
878
879 /* Don't show non-partitionable removeable devices or empty devices */
880 if (!get_capacity(sgp) || (!disk_max_parts(sgp) &&
881 (sgp->flags & GENHD_FL_REMOVABLE)))
882 return 0;
883 if (sgp->flags & GENHD_FL_SUPPRESS_PARTITION_INFO)
884 return 0;
885
886 /* show the full disk and all non-0 size partitions of it */
887 disk_part_iter_init(&piter, sgp, DISK_PITER_INCL_PART0);
888 while ((part = disk_part_iter_next(&piter)))
889 seq_printf(seqf, "%4d %7d %10llu %s\n",
890 MAJOR(part_devt(part)), MINOR(part_devt(part)),
891 (unsigned long long)part_nr_sects_read(part) >> 1,
892 disk_name(sgp, part->partno, buf));
893 disk_part_iter_exit(&piter);
894
895 return 0;
896}
897
898static const struct seq_operations partitions_op = {
899 .start = show_partition_start,
900 .next = disk_seqf_next,
901 .stop = disk_seqf_stop,
902 .show = show_partition
903};
904
905static int partitions_open(struct inode *inode, struct file *file)
906{
907 return seq_open(file, &partitions_op);
908}
909
910static const struct file_operations proc_partitions_operations = {
911 .open = partitions_open,
912 .read = seq_read,
913 .llseek = seq_lseek,
914 .release = seq_release,
915};
916#endif
917
918
919static struct kobject *base_probe(dev_t devt, int *partno, void *data)
920{
921 if (request_module("block-major-%d-%d", MAJOR(devt), MINOR(devt)) > 0)
922 /* Make old-style 2.4 aliases work */
923 request_module("block-major-%d", MAJOR(devt));
924 return NULL;
925}
926
927static int __init genhd_device_init(void)
928{
929 int error;
930
931 block_class.dev_kobj = sysfs_dev_block_kobj;
932 error = class_register(&block_class);
933 if (unlikely(error))
934 return error;
935 bdev_map = kobj_map_init(base_probe, &block_class_lock);
936 blk_dev_init();
937
938 register_blkdev(BLOCK_EXT_MAJOR, "blkext");
939
940 /* create top-level block dir */
941 if (!sysfs_deprecated)
942 block_depr = kobject_create_and_add("block", NULL);
943 return 0;
944}
945
946subsys_initcall(genhd_device_init);
947
948static ssize_t disk_range_show(struct device *dev,
949 struct device_attribute *attr, char *buf)
950{
951 struct gendisk *disk = dev_to_disk(dev);
952
953 return sprintf(buf, "%d\n", disk->minors);
954}
955
956static ssize_t disk_ext_range_show(struct device *dev,
957 struct device_attribute *attr, char *buf)
958{
959 struct gendisk *disk = dev_to_disk(dev);
960
961 return sprintf(buf, "%d\n", disk_max_parts(disk));
962}
963
964static ssize_t disk_removable_show(struct device *dev,
965 struct device_attribute *attr, char *buf)
966{
967 struct gendisk *disk = dev_to_disk(dev);
968
969 return sprintf(buf, "%d\n",
970 (disk->flags & GENHD_FL_REMOVABLE ? 1 : 0));
971}
972
973static ssize_t disk_ro_show(struct device *dev,
974 struct device_attribute *attr, char *buf)
975{
976 struct gendisk *disk = dev_to_disk(dev);
977
978 return sprintf(buf, "%d\n", get_disk_ro(disk) ? 1 : 0);
979}
980
981static ssize_t disk_capability_show(struct device *dev,
982 struct device_attribute *attr, char *buf)
983{
984 struct gendisk *disk = dev_to_disk(dev);
985
986 return sprintf(buf, "%x\n", disk->flags);
987}
988
989static ssize_t disk_alignment_offset_show(struct device *dev,
990 struct device_attribute *attr,
991 char *buf)
992{
993 struct gendisk *disk = dev_to_disk(dev);
994
995 return sprintf(buf, "%d\n", queue_alignment_offset(disk->queue));
996}
997
998static ssize_t disk_discard_alignment_show(struct device *dev,
999 struct device_attribute *attr,
1000 char *buf)
1001{
1002 struct gendisk *disk = dev_to_disk(dev);
1003
1004 return sprintf(buf, "%d\n", queue_discard_alignment(disk->queue));
1005}
1006
1007static DEVICE_ATTR(range, S_IRUGO, disk_range_show, NULL);
1008static DEVICE_ATTR(ext_range, S_IRUGO, disk_ext_range_show, NULL);
1009static DEVICE_ATTR(removable, S_IRUGO, disk_removable_show, NULL);
1010static DEVICE_ATTR(ro, S_IRUGO, disk_ro_show, NULL);
1011static DEVICE_ATTR(size, S_IRUGO, part_size_show, NULL);
1012static DEVICE_ATTR(alignment_offset, S_IRUGO, disk_alignment_offset_show, NULL);
1013static DEVICE_ATTR(discard_alignment, S_IRUGO, disk_discard_alignment_show,
1014 NULL);
1015static DEVICE_ATTR(capability, S_IRUGO, disk_capability_show, NULL);
1016static DEVICE_ATTR(stat, S_IRUGO, part_stat_show, NULL);
1017static DEVICE_ATTR(inflight, S_IRUGO, part_inflight_show, NULL);
1018static DEVICE_ATTR(badblocks, S_IRUGO | S_IWUSR, disk_badblocks_show,
1019 disk_badblocks_store);
1020#ifdef CONFIG_FAIL_MAKE_REQUEST
1021static struct device_attribute dev_attr_fail =
1022 __ATTR(make-it-fail, S_IRUGO|S_IWUSR, part_fail_show, part_fail_store);
1023#endif
1024#ifdef CONFIG_FAIL_IO_TIMEOUT
1025static struct device_attribute dev_attr_fail_timeout =
1026 __ATTR(io-timeout-fail, S_IRUGO|S_IWUSR, part_timeout_show,
1027 part_timeout_store);
1028#endif
1029
1030static struct attribute *disk_attrs[] = {
1031 &dev_attr_range.attr,
1032 &dev_attr_ext_range.attr,
1033 &dev_attr_removable.attr,
1034 &dev_attr_ro.attr,
1035 &dev_attr_size.attr,
1036 &dev_attr_alignment_offset.attr,
1037 &dev_attr_discard_alignment.attr,
1038 &dev_attr_capability.attr,
1039 &dev_attr_stat.attr,
1040 &dev_attr_inflight.attr,
1041 &dev_attr_badblocks.attr,
1042#ifdef CONFIG_FAIL_MAKE_REQUEST
1043 &dev_attr_fail.attr,
1044#endif
1045#ifdef CONFIG_FAIL_IO_TIMEOUT
1046 &dev_attr_fail_timeout.attr,
1047#endif
1048 NULL
1049};
1050
1051static struct attribute_group disk_attr_group = {
1052 .attrs = disk_attrs,
1053};
1054
1055static const struct attribute_group *disk_attr_groups[] = {
1056 &disk_attr_group,
1057 NULL
1058};
1059
1060/**
1061 * disk_replace_part_tbl - replace disk->part_tbl in RCU-safe way
1062 * @disk: disk to replace part_tbl for
1063 * @new_ptbl: new part_tbl to install
1064 *
1065 * Replace disk->part_tbl with @new_ptbl in RCU-safe way. The
1066 * original ptbl is freed using RCU callback.
1067 *
1068 * LOCKING:
1069 * Matching bd_mutx locked.
1070 */
1071static void disk_replace_part_tbl(struct gendisk *disk,
1072 struct disk_part_tbl *new_ptbl)
1073{
1074 struct disk_part_tbl *old_ptbl = disk->part_tbl;
1075
1076 rcu_assign_pointer(disk->part_tbl, new_ptbl);
1077
1078 if (old_ptbl) {
1079 rcu_assign_pointer(old_ptbl->last_lookup, NULL);
1080 kfree_rcu(old_ptbl, rcu_head);
1081 }
1082}
1083
1084/**
1085 * disk_expand_part_tbl - expand disk->part_tbl
1086 * @disk: disk to expand part_tbl for
1087 * @partno: expand such that this partno can fit in
1088 *
1089 * Expand disk->part_tbl such that @partno can fit in. disk->part_tbl
1090 * uses RCU to allow unlocked dereferencing for stats and other stuff.
1091 *
1092 * LOCKING:
1093 * Matching bd_mutex locked, might sleep.
1094 *
1095 * RETURNS:
1096 * 0 on success, -errno on failure.
1097 */
1098int disk_expand_part_tbl(struct gendisk *disk, int partno)
1099{
1100 struct disk_part_tbl *old_ptbl = disk->part_tbl;
1101 struct disk_part_tbl *new_ptbl;
1102 int len = old_ptbl ? old_ptbl->len : 0;
1103 int i, target;
1104 size_t size;
1105
1106 /*
1107 * check for int overflow, since we can get here from blkpg_ioctl()
1108 * with a user passed 'partno'.
1109 */
1110 target = partno + 1;
1111 if (target < 0)
1112 return -EINVAL;
1113
1114 /* disk_max_parts() is zero during initialization, ignore if so */
1115 if (disk_max_parts(disk) && target > disk_max_parts(disk))
1116 return -EINVAL;
1117
1118 if (target <= len)
1119 return 0;
1120
1121 size = sizeof(*new_ptbl) + target * sizeof(new_ptbl->part[0]);
1122 new_ptbl = kzalloc_node(size, GFP_KERNEL, disk->node_id);
1123 if (!new_ptbl)
1124 return -ENOMEM;
1125
1126 new_ptbl->len = target;
1127
1128 for (i = 0; i < len; i++)
1129 rcu_assign_pointer(new_ptbl->part[i], old_ptbl->part[i]);
1130
1131 disk_replace_part_tbl(disk, new_ptbl);
1132 return 0;
1133}
1134
1135static void disk_release(struct device *dev)
1136{
1137 struct gendisk *disk = dev_to_disk(dev);
1138
1139 blk_free_devt(dev->devt);
1140 disk_release_events(disk);
1141 kfree(disk->random);
1142 disk_replace_part_tbl(disk, NULL);
1143 hd_free_part(&disk->part0);
1144 if (disk->queue)
1145 blk_put_queue(disk->queue);
1146 kfree(disk);
1147}
1148struct class block_class = {
1149 .name = "block",
1150};
1151
1152static char *block_devnode(struct device *dev, umode_t *mode,
1153 kuid_t *uid, kgid_t *gid)
1154{
1155 struct gendisk *disk = dev_to_disk(dev);
1156
1157 if (disk->devnode)
1158 return disk->devnode(disk, mode);
1159 return NULL;
1160}
1161
1162static struct device_type disk_type = {
1163 .name = "disk",
1164 .groups = disk_attr_groups,
1165 .release = disk_release,
1166 .devnode = block_devnode,
1167};
1168
1169#ifdef CONFIG_PROC_FS
1170/*
1171 * aggregate disk stat collector. Uses the same stats that the sysfs
1172 * entries do, above, but makes them available through one seq_file.
1173 *
1174 * The output looks suspiciously like /proc/partitions with a bunch of
1175 * extra fields.
1176 */
1177static int diskstats_show(struct seq_file *seqf, void *v)
1178{
1179 struct gendisk *gp = v;
1180 struct disk_part_iter piter;
1181 struct hd_struct *hd;
1182 char buf[BDEVNAME_SIZE];
1183 int cpu;
1184
1185 /*
1186 if (&disk_to_dev(gp)->kobj.entry == block_class.devices.next)
1187 seq_puts(seqf, "major minor name"
1188 " rio rmerge rsect ruse wio wmerge "
1189 "wsect wuse running use aveq"
1190 "\n\n");
1191 */
1192
1193 disk_part_iter_init(&piter, gp, DISK_PITER_INCL_EMPTY_PART0);
1194 while ((hd = disk_part_iter_next(&piter))) {
1195 cpu = part_stat_lock();
1196 part_round_stats(cpu, hd);
1197 part_stat_unlock();
1198 seq_printf(seqf, "%4d %7d %s %lu %lu %lu "
1199 "%u %lu %lu %lu %u %u %u %u\n",
1200 MAJOR(part_devt(hd)), MINOR(part_devt(hd)),
1201 disk_name(gp, hd->partno, buf),
1202 part_stat_read(hd, ios[READ]),
1203 part_stat_read(hd, merges[READ]),
1204 part_stat_read(hd, sectors[READ]),
1205 jiffies_to_msecs(part_stat_read(hd, ticks[READ])),
1206 part_stat_read(hd, ios[WRITE]),
1207 part_stat_read(hd, merges[WRITE]),
1208 part_stat_read(hd, sectors[WRITE]),
1209 jiffies_to_msecs(part_stat_read(hd, ticks[WRITE])),
1210 part_in_flight(hd),
1211 jiffies_to_msecs(part_stat_read(hd, io_ticks)),
1212 jiffies_to_msecs(part_stat_read(hd, time_in_queue))
1213 );
1214 }
1215 disk_part_iter_exit(&piter);
1216
1217 return 0;
1218}
1219
1220static const struct seq_operations diskstats_op = {
1221 .start = disk_seqf_start,
1222 .next = disk_seqf_next,
1223 .stop = disk_seqf_stop,
1224 .show = diskstats_show
1225};
1226
1227static int diskstats_open(struct inode *inode, struct file *file)
1228{
1229 return seq_open(file, &diskstats_op);
1230}
1231
1232static const struct file_operations proc_diskstats_operations = {
1233 .open = diskstats_open,
1234 .read = seq_read,
1235 .llseek = seq_lseek,
1236 .release = seq_release,
1237};
1238
1239static int __init proc_genhd_init(void)
1240{
1241 proc_create("diskstats", 0, NULL, &proc_diskstats_operations);
1242 proc_create("partitions", 0, NULL, &proc_partitions_operations);
1243 return 0;
1244}
1245module_init(proc_genhd_init);
1246#endif /* CONFIG_PROC_FS */
1247
1248dev_t blk_lookup_devt(const char *name, int partno)
1249{
1250 dev_t devt = MKDEV(0, 0);
1251 struct class_dev_iter iter;
1252 struct device *dev;
1253
1254 class_dev_iter_init(&iter, &block_class, NULL, &disk_type);
1255 while ((dev = class_dev_iter_next(&iter))) {
1256 struct gendisk *disk = dev_to_disk(dev);
1257 struct hd_struct *part;
1258
1259 if (strcmp(dev_name(dev), name))
1260 continue;
1261
1262 if (partno < disk->minors) {
1263 /* We need to return the right devno, even
1264 * if the partition doesn't exist yet.
1265 */
1266 devt = MKDEV(MAJOR(dev->devt),
1267 MINOR(dev->devt) + partno);
1268 break;
1269 }
1270 part = disk_get_part(disk, partno);
1271 if (part) {
1272 devt = part_devt(part);
1273 disk_put_part(part);
1274 break;
1275 }
1276 disk_put_part(part);
1277 }
1278 class_dev_iter_exit(&iter);
1279 return devt;
1280}
1281EXPORT_SYMBOL(blk_lookup_devt);
1282
1283struct gendisk *alloc_disk(int minors)
1284{
1285 return alloc_disk_node(minors, NUMA_NO_NODE);
1286}
1287EXPORT_SYMBOL(alloc_disk);
1288
1289struct gendisk *alloc_disk_node(int minors, int node_id)
1290{
1291 struct gendisk *disk;
1292
1293 disk = kzalloc_node(sizeof(struct gendisk), GFP_KERNEL, node_id);
1294 if (disk) {
1295 if (!init_part_stats(&disk->part0)) {
1296 kfree(disk);
1297 return NULL;
1298 }
1299 disk->node_id = node_id;
1300 if (disk_expand_part_tbl(disk, 0)) {
1301 free_part_stats(&disk->part0);
1302 kfree(disk);
1303 return NULL;
1304 }
1305 disk->part_tbl->part[0] = &disk->part0;
1306
1307 /*
1308 * set_capacity() and get_capacity() currently don't use
1309 * seqcounter to read/update the part0->nr_sects. Still init
1310 * the counter as we can read the sectors in IO submission
1311 * patch using seqence counters.
1312 *
1313 * TODO: Ideally set_capacity() and get_capacity() should be
1314 * converted to make use of bd_mutex and sequence counters.
1315 */
1316 seqcount_init(&disk->part0.nr_sects_seq);
1317 if (hd_ref_init(&disk->part0)) {
1318 hd_free_part(&disk->part0);
1319 kfree(disk);
1320 return NULL;
1321 }
1322
1323 disk->minors = minors;
1324 rand_initialize_disk(disk);
1325 disk_to_dev(disk)->class = &block_class;
1326 disk_to_dev(disk)->type = &disk_type;
1327 device_initialize(disk_to_dev(disk));
1328 }
1329 return disk;
1330}
1331EXPORT_SYMBOL(alloc_disk_node);
1332
1333struct kobject *get_disk(struct gendisk *disk)
1334{
1335 struct module *owner;
1336 struct kobject *kobj;
1337
1338 if (!disk->fops)
1339 return NULL;
1340 owner = disk->fops->owner;
1341 if (owner && !try_module_get(owner))
1342 return NULL;
1343 kobj = kobject_get(&disk_to_dev(disk)->kobj);
1344 if (kobj == NULL) {
1345 module_put(owner);
1346 return NULL;
1347 }
1348 return kobj;
1349
1350}
1351
1352EXPORT_SYMBOL(get_disk);
1353
1354void put_disk(struct gendisk *disk)
1355{
1356 if (disk)
1357 kobject_put(&disk_to_dev(disk)->kobj);
1358}
1359
1360EXPORT_SYMBOL(put_disk);
1361
1362static void set_disk_ro_uevent(struct gendisk *gd, int ro)
1363{
1364 char event[] = "DISK_RO=1";
1365 char *envp[] = { event, NULL };
1366
1367 if (!ro)
1368 event[8] = '0';
1369 kobject_uevent_env(&disk_to_dev(gd)->kobj, KOBJ_CHANGE, envp);
1370}
1371
1372void set_device_ro(struct block_device *bdev, int flag)
1373{
1374 bdev->bd_part->policy = flag;
1375}
1376
1377EXPORT_SYMBOL(set_device_ro);
1378
1379void set_disk_ro(struct gendisk *disk, int flag)
1380{
1381 struct disk_part_iter piter;
1382 struct hd_struct *part;
1383
1384 if (disk->part0.policy != flag) {
1385 set_disk_ro_uevent(disk, flag);
1386 disk->part0.policy = flag;
1387 }
1388
1389 disk_part_iter_init(&piter, disk, DISK_PITER_INCL_EMPTY);
1390 while ((part = disk_part_iter_next(&piter)))
1391 part->policy = flag;
1392 disk_part_iter_exit(&piter);
1393}
1394
1395EXPORT_SYMBOL(set_disk_ro);
1396
1397int bdev_read_only(struct block_device *bdev)
1398{
1399 if (!bdev)
1400 return 0;
1401 return bdev->bd_part->policy;
1402}
1403
1404EXPORT_SYMBOL(bdev_read_only);
1405
1406int invalidate_partition(struct gendisk *disk, int partno)
1407{
1408 int res = 0;
1409 struct block_device *bdev = bdget_disk(disk, partno);
1410 if (bdev) {
1411 fsync_bdev(bdev);
1412 res = __invalidate_device(bdev, true);
1413 bdput(bdev);
1414 }
1415 return res;
1416}
1417
1418EXPORT_SYMBOL(invalidate_partition);
1419
1420/*
1421 * Disk events - monitor disk events like media change and eject request.
1422 */
1423struct disk_events {
1424 struct list_head node; /* all disk_event's */
1425 struct gendisk *disk; /* the associated disk */
1426 spinlock_t lock;
1427
1428 struct mutex block_mutex; /* protects blocking */
1429 int block; /* event blocking depth */
1430 unsigned int pending; /* events already sent out */
1431 unsigned int clearing; /* events being cleared */
1432
1433 long poll_msecs; /* interval, -1 for default */
1434 struct delayed_work dwork;
1435};
1436
1437static const char *disk_events_strs[] = {
1438 [ilog2(DISK_EVENT_MEDIA_CHANGE)] = "media_change",
1439 [ilog2(DISK_EVENT_EJECT_REQUEST)] = "eject_request",
1440};
1441
1442static char *disk_uevents[] = {
1443 [ilog2(DISK_EVENT_MEDIA_CHANGE)] = "DISK_MEDIA_CHANGE=1",
1444 [ilog2(DISK_EVENT_EJECT_REQUEST)] = "DISK_EJECT_REQUEST=1",
1445};
1446
1447/* list of all disk_events */
1448static DEFINE_MUTEX(disk_events_mutex);
1449static LIST_HEAD(disk_events);
1450
1451/* disable in-kernel polling by default */
1452static unsigned long disk_events_dfl_poll_msecs;
1453
1454static unsigned long disk_events_poll_jiffies(struct gendisk *disk)
1455{
1456 struct disk_events *ev = disk->ev;
1457 long intv_msecs = 0;
1458
1459 /*
1460 * If device-specific poll interval is set, always use it. If
1461 * the default is being used, poll iff there are events which
1462 * can't be monitored asynchronously.
1463 */
1464 if (ev->poll_msecs >= 0)
1465 intv_msecs = ev->poll_msecs;
1466 else if (disk->events & ~disk->async_events)
1467 intv_msecs = disk_events_dfl_poll_msecs;
1468
1469 return msecs_to_jiffies(intv_msecs);
1470}
1471
1472/**
1473 * disk_block_events - block and flush disk event checking
1474 * @disk: disk to block events for
1475 *
1476 * On return from this function, it is guaranteed that event checking
1477 * isn't in progress and won't happen until unblocked by
1478 * disk_unblock_events(). Events blocking is counted and the actual
1479 * unblocking happens after the matching number of unblocks are done.
1480 *
1481 * Note that this intentionally does not block event checking from
1482 * disk_clear_events().
1483 *
1484 * CONTEXT:
1485 * Might sleep.
1486 */
1487void disk_block_events(struct gendisk *disk)
1488{
1489 struct disk_events *ev = disk->ev;
1490 unsigned long flags;
1491 bool cancel;
1492
1493 if (!ev)
1494 return;
1495
1496 /*
1497 * Outer mutex ensures that the first blocker completes canceling
1498 * the event work before further blockers are allowed to finish.
1499 */
1500 mutex_lock(&ev->block_mutex);
1501
1502 spin_lock_irqsave(&ev->lock, flags);
1503 cancel = !ev->block++;
1504 spin_unlock_irqrestore(&ev->lock, flags);
1505
1506 if (cancel)
1507 cancel_delayed_work_sync(&disk->ev->dwork);
1508
1509 mutex_unlock(&ev->block_mutex);
1510}
1511
1512static void __disk_unblock_events(struct gendisk *disk, bool check_now)
1513{
1514 struct disk_events *ev = disk->ev;
1515 unsigned long intv;
1516 unsigned long flags;
1517
1518 spin_lock_irqsave(&ev->lock, flags);
1519
1520 if (WARN_ON_ONCE(ev->block <= 0))
1521 goto out_unlock;
1522
1523 if (--ev->block)
1524 goto out_unlock;
1525
1526 /*
1527 * Not exactly a latency critical operation, set poll timer
1528 * slack to 25% and kick event check.
1529 */
1530 intv = disk_events_poll_jiffies(disk);
1531 set_timer_slack(&ev->dwork.timer, intv / 4);
1532 if (check_now)
1533 queue_delayed_work(system_freezable_power_efficient_wq,
1534 &ev->dwork, 0);
1535 else if (intv)
1536 queue_delayed_work(system_freezable_power_efficient_wq,
1537 &ev->dwork, intv);
1538out_unlock:
1539 spin_unlock_irqrestore(&ev->lock, flags);
1540}
1541
1542/**
1543 * disk_unblock_events - unblock disk event checking
1544 * @disk: disk to unblock events for
1545 *
1546 * Undo disk_block_events(). When the block count reaches zero, it
1547 * starts events polling if configured.
1548 *
1549 * CONTEXT:
1550 * Don't care. Safe to call from irq context.
1551 */
1552void disk_unblock_events(struct gendisk *disk)
1553{
1554 if (disk->ev)
1555 __disk_unblock_events(disk, false);
1556}
1557
1558/**
1559 * disk_flush_events - schedule immediate event checking and flushing
1560 * @disk: disk to check and flush events for
1561 * @mask: events to flush
1562 *
1563 * Schedule immediate event checking on @disk if not blocked. Events in
1564 * @mask are scheduled to be cleared from the driver. Note that this
1565 * doesn't clear the events from @disk->ev.
1566 *
1567 * CONTEXT:
1568 * If @mask is non-zero must be called with bdev->bd_mutex held.
1569 */
1570void disk_flush_events(struct gendisk *disk, unsigned int mask)
1571{
1572 struct disk_events *ev = disk->ev;
1573
1574 if (!ev)
1575 return;
1576
1577 spin_lock_irq(&ev->lock);
1578 ev->clearing |= mask;
1579 if (!ev->block)
1580 mod_delayed_work(system_freezable_power_efficient_wq,
1581 &ev->dwork, 0);
1582 spin_unlock_irq(&ev->lock);
1583}
1584
1585/**
1586 * disk_clear_events - synchronously check, clear and return pending events
1587 * @disk: disk to fetch and clear events from
1588 * @mask: mask of events to be fetched and cleared
1589 *
1590 * Disk events are synchronously checked and pending events in @mask
1591 * are cleared and returned. This ignores the block count.
1592 *
1593 * CONTEXT:
1594 * Might sleep.
1595 */
1596unsigned int disk_clear_events(struct gendisk *disk, unsigned int mask)
1597{
1598 const struct block_device_operations *bdops = disk->fops;
1599 struct disk_events *ev = disk->ev;
1600 unsigned int pending;
1601 unsigned int clearing = mask;
1602
1603 if (!ev) {
1604 /* for drivers still using the old ->media_changed method */
1605 if ((mask & DISK_EVENT_MEDIA_CHANGE) &&
1606 bdops->media_changed && bdops->media_changed(disk))
1607 return DISK_EVENT_MEDIA_CHANGE;
1608 return 0;
1609 }
1610
1611 disk_block_events(disk);
1612
1613 /*
1614 * store the union of mask and ev->clearing on the stack so that the
1615 * race with disk_flush_events does not cause ambiguity (ev->clearing
1616 * can still be modified even if events are blocked).
1617 */
1618 spin_lock_irq(&ev->lock);
1619 clearing |= ev->clearing;
1620 ev->clearing = 0;
1621 spin_unlock_irq(&ev->lock);
1622
1623 disk_check_events(ev, &clearing);
1624 /*
1625 * if ev->clearing is not 0, the disk_flush_events got called in the
1626 * middle of this function, so we want to run the workfn without delay.
1627 */
1628 __disk_unblock_events(disk, ev->clearing ? true : false);
1629
1630 /* then, fetch and clear pending events */
1631 spin_lock_irq(&ev->lock);
1632 pending = ev->pending & mask;
1633 ev->pending &= ~mask;
1634 spin_unlock_irq(&ev->lock);
1635 WARN_ON_ONCE(clearing & mask);
1636
1637 return pending;
1638}
1639
1640/*
1641 * Separate this part out so that a different pointer for clearing_ptr can be
1642 * passed in for disk_clear_events.
1643 */
1644static void disk_events_workfn(struct work_struct *work)
1645{
1646 struct delayed_work *dwork = to_delayed_work(work);
1647 struct disk_events *ev = container_of(dwork, struct disk_events, dwork);
1648
1649 disk_check_events(ev, &ev->clearing);
1650}
1651
1652static void disk_check_events(struct disk_events *ev,
1653 unsigned int *clearing_ptr)
1654{
1655 struct gendisk *disk = ev->disk;
1656 char *envp[ARRAY_SIZE(disk_uevents) + 1] = { };
1657 unsigned int clearing = *clearing_ptr;
1658 unsigned int events;
1659 unsigned long intv;
1660 int nr_events = 0, i;
1661
1662 /* check events */
1663 events = disk->fops->check_events(disk, clearing);
1664
1665 /* accumulate pending events and schedule next poll if necessary */
1666 spin_lock_irq(&ev->lock);
1667
1668 events &= ~ev->pending;
1669 ev->pending |= events;
1670 *clearing_ptr &= ~clearing;
1671
1672 intv = disk_events_poll_jiffies(disk);
1673 if (!ev->block && intv)
1674 queue_delayed_work(system_freezable_power_efficient_wq,
1675 &ev->dwork, intv);
1676
1677 spin_unlock_irq(&ev->lock);
1678
1679 /*
1680 * Tell userland about new events. Only the events listed in
1681 * @disk->events are reported. Unlisted events are processed the
1682 * same internally but never get reported to userland.
1683 */
1684 for (i = 0; i < ARRAY_SIZE(disk_uevents); i++)
1685 if (events & disk->events & (1 << i))
1686 envp[nr_events++] = disk_uevents[i];
1687
1688 if (nr_events)
1689 kobject_uevent_env(&disk_to_dev(disk)->kobj, KOBJ_CHANGE, envp);
1690}
1691
1692/*
1693 * A disk events enabled device has the following sysfs nodes under
1694 * its /sys/block/X/ directory.
1695 *
1696 * events : list of all supported events
1697 * events_async : list of events which can be detected w/o polling
1698 * events_poll_msecs : polling interval, 0: disable, -1: system default
1699 */
1700static ssize_t __disk_events_show(unsigned int events, char *buf)
1701{
1702 const char *delim = "";
1703 ssize_t pos = 0;
1704 int i;
1705
1706 for (i = 0; i < ARRAY_SIZE(disk_events_strs); i++)
1707 if (events & (1 << i)) {
1708 pos += sprintf(buf + pos, "%s%s",
1709 delim, disk_events_strs[i]);
1710 delim = " ";
1711 }
1712 if (pos)
1713 pos += sprintf(buf + pos, "\n");
1714 return pos;
1715}
1716
1717static ssize_t disk_events_show(struct device *dev,
1718 struct device_attribute *attr, char *buf)
1719{
1720 struct gendisk *disk = dev_to_disk(dev);
1721
1722 return __disk_events_show(disk->events, buf);
1723}
1724
1725static ssize_t disk_events_async_show(struct device *dev,
1726 struct device_attribute *attr, char *buf)
1727{
1728 struct gendisk *disk = dev_to_disk(dev);
1729
1730 return __disk_events_show(disk->async_events, buf);
1731}
1732
1733static ssize_t disk_events_poll_msecs_show(struct device *dev,
1734 struct device_attribute *attr,
1735 char *buf)
1736{
1737 struct gendisk *disk = dev_to_disk(dev);
1738
1739 return sprintf(buf, "%ld\n", disk->ev->poll_msecs);
1740}
1741
1742static ssize_t disk_events_poll_msecs_store(struct device *dev,
1743 struct device_attribute *attr,
1744 const char *buf, size_t count)
1745{
1746 struct gendisk *disk = dev_to_disk(dev);
1747 long intv;
1748
1749 if (!count || !sscanf(buf, "%ld", &intv))
1750 return -EINVAL;
1751
1752 if (intv < 0 && intv != -1)
1753 return -EINVAL;
1754
1755 disk_block_events(disk);
1756 disk->ev->poll_msecs = intv;
1757 __disk_unblock_events(disk, true);
1758
1759 return count;
1760}
1761
1762static const DEVICE_ATTR(events, S_IRUGO, disk_events_show, NULL);
1763static const DEVICE_ATTR(events_async, S_IRUGO, disk_events_async_show, NULL);
1764static const DEVICE_ATTR(events_poll_msecs, S_IRUGO|S_IWUSR,
1765 disk_events_poll_msecs_show,
1766 disk_events_poll_msecs_store);
1767
1768static const struct attribute *disk_events_attrs[] = {
1769 &dev_attr_events.attr,
1770 &dev_attr_events_async.attr,
1771 &dev_attr_events_poll_msecs.attr,
1772 NULL,
1773};
1774
1775/*
1776 * The default polling interval can be specified by the kernel
1777 * parameter block.events_dfl_poll_msecs which defaults to 0
1778 * (disable). This can also be modified runtime by writing to
1779 * /sys/module/block/events_dfl_poll_msecs.
1780 */
1781static int disk_events_set_dfl_poll_msecs(const char *val,
1782 const struct kernel_param *kp)
1783{
1784 struct disk_events *ev;
1785 int ret;
1786
1787 ret = param_set_ulong(val, kp);
1788 if (ret < 0)
1789 return ret;
1790
1791 mutex_lock(&disk_events_mutex);
1792
1793 list_for_each_entry(ev, &disk_events, node)
1794 disk_flush_events(ev->disk, 0);
1795
1796 mutex_unlock(&disk_events_mutex);
1797
1798 return 0;
1799}
1800
1801static const struct kernel_param_ops disk_events_dfl_poll_msecs_param_ops = {
1802 .set = disk_events_set_dfl_poll_msecs,
1803 .get = param_get_ulong,
1804};
1805
1806#undef MODULE_PARAM_PREFIX
1807#define MODULE_PARAM_PREFIX "block."
1808
1809module_param_cb(events_dfl_poll_msecs, &disk_events_dfl_poll_msecs_param_ops,
1810 &disk_events_dfl_poll_msecs, 0644);
1811
1812/*
1813 * disk_{alloc|add|del|release}_events - initialize and destroy disk_events.
1814 */
1815static void disk_alloc_events(struct gendisk *disk)
1816{
1817 struct disk_events *ev;
1818
1819 if (!disk->fops->check_events)
1820 return;
1821
1822 ev = kzalloc(sizeof(*ev), GFP_KERNEL);
1823 if (!ev) {
1824 pr_warn("%s: failed to initialize events\n", disk->disk_name);
1825 return;
1826 }
1827
1828 INIT_LIST_HEAD(&ev->node);
1829 ev->disk = disk;
1830 spin_lock_init(&ev->lock);
1831 mutex_init(&ev->block_mutex);
1832 ev->block = 1;
1833 ev->poll_msecs = -1;
1834 INIT_DELAYED_WORK(&ev->dwork, disk_events_workfn);
1835
1836 disk->ev = ev;
1837}
1838
1839static void disk_add_events(struct gendisk *disk)
1840{
1841 if (!disk->ev)
1842 return;
1843
1844 /* FIXME: error handling */
1845 if (sysfs_create_files(&disk_to_dev(disk)->kobj, disk_events_attrs) < 0)
1846 pr_warn("%s: failed to create sysfs files for events\n",
1847 disk->disk_name);
1848
1849 mutex_lock(&disk_events_mutex);
1850 list_add_tail(&disk->ev->node, &disk_events);
1851 mutex_unlock(&disk_events_mutex);
1852
1853 /*
1854 * Block count is initialized to 1 and the following initial
1855 * unblock kicks it into action.
1856 */
1857 __disk_unblock_events(disk, true);
1858}
1859
1860static void disk_del_events(struct gendisk *disk)
1861{
1862 if (!disk->ev)
1863 return;
1864
1865 disk_block_events(disk);
1866
1867 mutex_lock(&disk_events_mutex);
1868 list_del_init(&disk->ev->node);
1869 mutex_unlock(&disk_events_mutex);
1870
1871 sysfs_remove_files(&disk_to_dev(disk)->kobj, disk_events_attrs);
1872}
1873
1874static void disk_release_events(struct gendisk *disk)
1875{
1876 /* the block count should be 1 from disk_del_events() */
1877 WARN_ON_ONCE(disk->ev && disk->ev->block != 1);
1878 kfree(disk->ev);
1879}
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(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(&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 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(&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 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(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->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 else
269 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's
355 * safe to scan partitons, otherwise, use bd_prepare_to_claim() to
356 * synchronize with other exclusive openers and other partition
357 * 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 else
372 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 will
377 * 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 list
387 * @parent: parent device for the disk
388 * @disk: per-device partitioning information
389 * @groups: Additional per-device sysfs groups
390 *
391 * This function registers the partitioning information in @disk
392 * 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 about
407 * the device for the elevator code to pick an adequate default
408 * elevator if one is needed, that is, for devices requesting queue
409 * registration.
410 */
411 elevator_init_mq(disk->queue);
412
413 /* Mark bdev as having a submit_bio, if needed */
414 disk->part0->bd_has_submit_bio = disk->fops->submit_bio != NULL;
415
416 /*
417 * If the driver provides an explicit major number it also must provide
418 * the number of minors numbers supported, and those will be used to
419 * setup the gendisk.
420 * Otherwise just allocate the device numbers for both the whole device
421 * and all partitions from the extended dev_t space.
422 */
423 ret = -EINVAL;
424 if (disk->major) {
425 if (WARN_ON(!disk->minors))
426 goto out_exit_elevator;
427
428 if (disk->minors > DISK_MAX_PARTS) {
429 pr_err("block: can't allocate more than %d partitions\n",
430 DISK_MAX_PARTS);
431 disk->minors = DISK_MAX_PARTS;
432 }
433 if (disk->first_minor > MINORMASK ||
434 disk->minors > MINORMASK + 1 ||
435 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(ddev, 1);
450
451 ddev->parent = parent;
452 ddev->groups = groups;
453 dev_set_name(ddev, "%s", disk->disk_name);
454 if (!(disk->flags & GENHD_FL_HIDDEN))
455 ddev->devt = MKDEV(disk->major, disk->first_minor);
456 ret = device_add(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(block_depr, &ddev->kobj,
465 kobject_name(&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(ddev, true);
475
476 disk->part0->bd_holder_dir =
477 kobject_create_and_add("holders", &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("slaves", &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(disk->bdi, "%u:%u",
494 disk->major, disk->first_minor);
495 if (ret)
496 goto out_unregister_queue;
497 bdi_set_owner(disk->bdi, ddev);
498 ret = sysfs_create_link(&ddev->kobj,
499 &disk->bdi->dev->kobj, "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_has_partscan(disk))
505 set_bit(GD_NEED_PART_SCAN, &disk->state);
506
507 bdev_add(disk->part0, ddev->devt);
508 if (get_capacity(disk))
509 disk_scan_partitions(disk, BLK_OPEN_READ);
510
511 /*
512 * Announce the disk and partitions after all partitions are
513 * created. (for hidden disks uevents remain suppressed forever)
514 */
515 dev_set_uevent_suppress(ddev, 0);
516 disk_uevent(disk, KOBJ_ADD);
517 } else {
518 /*
519 * Even if the block_device for a hidden gendisk is not
520 * registered, it needs to have a valid bd_dev so that the
521 * freeing of the dynamic major works.
522 */
523 disk->part0->bd_dev = MKDEV(disk->major, disk->first_minor);
524 }
525
526 disk_update_readahead(disk);
527 disk_add_events(disk);
528 set_bit(GD_ADDED, &disk->state);
529 return 0;
530
531out_unregister_bdi:
532 if (!(disk->flags & GENHD_FL_HIDDEN))
533 bdi_unregister(disk->bdi);
534out_unregister_queue:
535 blk_unregister_queue(disk);
536 rq_qos_exit(disk->queue);
537out_put_slave_dir:
538 kobject_put(disk->slave_dir);
539 disk->slave_dir = NULL;
540out_put_holder_dir:
541 kobject_put(disk->part0->bd_holder_dir);
542out_del_block_link:
543 sysfs_remove_link(block_depr, dev_name(ddev));
544 pm_runtime_set_memalloc_noio(ddev, false);
545out_device_del:
546 device_del(ddev);
547out_free_ext_minor:
548 if (disk->major == BLOCK_EXT_MAJOR)
549 blk_free_ext_minor(disk->first_minor);
550out_exit_elevator:
551 if (disk->queue->elevator)
552 elevator_exit(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(&bdev->bd_device.kobj))
572 continue;
573 rcu_read_unlock();
574
575 bdev_mark_dead(bdev, surprise);
576
577 put_device(&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, &disk->state))
589 return;
590
591 if (test_bit(GD_OWNS_QUEUE, &disk->state))
592 blk_queue_flag_set(QUEUE_FLAG_DYING, 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(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, 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(part->bd_inode);
657 mutex_unlock(&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, 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(&disk->open_mutex);
674
675 if (!(disk->flags & GENHD_FL_HIDDEN)) {
676 sysfs_remove_link(&disk_to_dev(disk)->kobj, "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(disk->bdi);
683 }
684
685 blk_unregister_queue(disk);
686
687 kobject_put(disk->part0->bd_holder_dir);
688 kobject_put(disk->slave_dir);
689 disk->slave_dir = NULL;
690
691 part_stat_set_all(disk->part0, 0);
692 disk->part0->bd_stamp = 0;
693 sysfs_remove_link(block_depr, dev_name(disk_to_dev(disk)));
694 pm_runtime_set_memalloc_noio(disk_to_dev(disk), 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(&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, 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(page, "\n");
759
760 return badblocks_show(disk->bb, page, 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(disk->bb, page, len, 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(&major_names_lock);
786 return;
787 }
788 }
789 mutex_unlock(&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(sizeof(*iter), GFP_KERNEL);
806 if (!iter)
807 return ERR_PTR(-ENOMEM);
808
809 seqf->private = iter;
810 class_dev_iter_init(iter, &block_class, NULL, &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(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(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(p) && !*pos)
850 seq_puts(seqf, "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(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(part))
866 continue;
867 seq_printf(seqf, "%4d %7d %10llu %pg\n",
868 MAJOR(part->bd_dev), MINOR(part->bd_dev),
869 bdev_nr_sectors(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(&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("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, "%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, "%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, "%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, "%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, "%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, "%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, bdev);
960 else
961 inflight = part_in_flight(bdev);
962
963 if (inflight) {
964 part_stat_lock();
965 update_io_ticks(bdev, jiffies, true);
966 part_stat_unlock();
967 }
968 part_stat_read_all(bdev, &stat);
969 return sprintf(buf,
970 "%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(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(stat.nsecs[STAT_WRITE], NSEC_PER_MSEC),
984 inflight,
985 jiffies_to_msecs(stat.io_ticks),
986 (unsigned int)div_u64(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(stat.nsecs[STAT_DISCARD], NSEC_PER_MSEC),
995 stat.ios[STAT_FLUSH],
996 (unsigned int)div_u64(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, bdev, inflight);
1008 else
1009 part_in_flight_rw(bdev, inflight);
1010
1011 return sprintf(buf, "%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, "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, "%d\n", bdev_alignment_offset(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, "%d\n", bdev_alignment_offset(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, "%llu\n", disk->diskseq);
1045}
1046
1047static ssize_t partscan_show(struct device *dev,
1048 struct device_attribute *attr, char *buf)
1049{
1050 return sprintf(buf, "%u\n", disk_has_partscan(dev_to_disk(dev)));
1051}
1052
1053static DEVICE_ATTR(range, 0444, disk_range_show, NULL);
1054static DEVICE_ATTR(ext_range, 0444, disk_ext_range_show, NULL);
1055static DEVICE_ATTR(removable, 0444, disk_removable_show, NULL);
1056static DEVICE_ATTR(hidden, 0444, disk_hidden_show, NULL);
1057static DEVICE_ATTR(ro, 0444, disk_ro_show, NULL);
1058static DEVICE_ATTR(size, 0444, part_size_show, NULL);
1059static DEVICE_ATTR(alignment_offset, 0444, disk_alignment_offset_show, NULL);
1060static DEVICE_ATTR(discard_alignment, 0444, disk_discard_alignment_show, NULL);
1061static DEVICE_ATTR(capability, 0444, disk_capability_show, NULL);
1062static DEVICE_ATTR(stat, 0444, part_stat_show, NULL);
1063static DEVICE_ATTR(inflight, 0444, part_inflight_show, NULL);
1064static DEVICE_ATTR(badblocks, 0644, disk_badblocks_show, disk_badblocks_store);
1065static DEVICE_ATTR(diskseq, 0444, diskseq_show, NULL);
1066static DEVICE_ATTR(partscan, 0444, partscan_show, NULL);
1067
1068#ifdef CONFIG_FAIL_MAKE_REQUEST
1069ssize_t part_fail_show(struct device *dev,
1070 struct device_attribute *attr, char *buf)
1071{
1072 return sprintf(buf, "%d\n", dev_to_bdev(dev)->bd_make_it_fail);
1073}
1074
1075ssize_t part_fail_store(struct device *dev,
1076 struct device_attribute *attr,
1077 const char *buf, size_t count)
1078{
1079 int i;
1080
1081 if (count > 0 && sscanf(buf, "%d", &i) > 0)
1082 dev_to_bdev(dev)->bd_make_it_fail = i;
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_TIMEOUT
1092static struct device_attribute dev_attr_fail_timeout =
1093 __ATTR(io-timeout-fail, 0644, part_timeout_show, part_timeout_store);
1094#endif
1095
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_REQUEST
1115 &dev_attr_fail.attr,
1116#endif
1117#ifdef CONFIG_FAIL_IO_TIMEOUT
1118 &dev_attr_fail_timeout.attr,
1119#endif
1120 NULL
1121};
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_TRACE
1141 &blk_trace_attr_group,
1142#endif
1143#ifdef CONFIG_BLK_DEV_INTEGRITY
1144 &blk_integrity_attr_group,
1145#endif
1146 NULL
1147};
1148
1149/**
1150 * disk_release - releases all allocated resources of the gendisk
1151 * @dev: the device representing this disk
1152 *
1153 * This function releases all allocated resources of the gendisk.
1154 *
1155 * Drivers which used __device_add_disk() have a gendisk with a request_queue
1156 * assigned. Since the request_queue sits on top of the gendisk for these
1157 * drivers we also call blk_put_queue() for them, and we expect the
1158 * request_queue refcount to reach 0 at this point, and so the request_queue
1159 * will also be freed prior to the disk.
1160 *
1161 * Context: can sleep
1162 */
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 in
1174 * case of a probe failure where add_disk is never called we have to
1175 * call blk_mq_exit_queue here. We can't do this for the more common
1176 * teardown case (yet) as the tagset can be gone by the time the disk
1177 * 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_bitmaps(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 iput(disk->part0->bd_inode); /* 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_FS
1232/*
1233 * aggregate disk stat collector. Uses the same stats that the sysfs
1234 * entries do, above, but makes them available through one seq_file.
1235 *
1236 * The output looks suspiciously like /proc/partitions with a bunch of
1237 * 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 if (queue_is_mq(gp->queue))
1260 inflight = blk_mq_in_flight(gp->queue, hd);
1261 else
1262 inflight = part_in_flight(hd);
1263
1264 if (inflight) {
1265 part_stat_lock();
1266 update_io_ticks(hd, jiffies, true);
1267 part_stat_unlock();
1268 }
1269 part_stat_read_all(hd, &stat);
1270 seq_printf(seqf, "%4d %7d %pg "
1271 "%lu %lu %lu %u "
1272 "%lu %lu %lu %u "
1273 "%u %u %u "
1274 "%lu %lu %lu %u "
1275 "%lu %u"
1276 "\n",
1277 MAJOR(hd->bd_dev), MINOR(hd->bd_dev), hd,
1278 stat.ios[STAT_READ],
1279 stat.merges[STAT_READ],
1280 stat.sectors[STAT_READ],
1281 (unsigned int)div_u64(stat.nsecs[STAT_READ],
1282 NSEC_PER_MSEC),
1283 stat.ios[STAT_WRITE],
1284 stat.merges[STAT_WRITE],
1285 stat.sectors[STAT_WRITE],
1286 (unsigned int)div_u64(stat.nsecs[STAT_WRITE],
1287 NSEC_PER_MSEC),
1288 inflight,
1289 jiffies_to_msecs(stat.io_ticks),
1290 (unsigned int)div_u64(stat.nsecs[STAT_READ] +
1291 stat.nsecs[STAT_WRITE] +
1292 stat.nsecs[STAT_DISCARD] +
1293 stat.nsecs[STAT_FLUSH],
1294 NSEC_PER_MSEC),
1295 stat.ios[STAT_DISCARD],
1296 stat.merges[STAT_DISCARD],
1297 stat.sectors[STAT_DISCARD],
1298 (unsigned int)div_u64(stat.nsecs[STAT_DISCARD],
1299 NSEC_PER_MSEC),
1300 stat.ios[STAT_FLUSH],
1301 (unsigned int)div_u64(stat.nsecs[STAT_FLUSH],
1302 NSEC_PER_MSEC)
1303 );
1304 }
1305 rcu_read_unlock();
1306
1307 return 0;
1308}
1309
1310static const struct seq_operations diskstats_op = {
1311 .start = disk_seqf_start,
1312 .next = disk_seqf_next,
1313 .stop = disk_seqf_stop,
1314 .show = diskstats_show
1315};
1316
1317static int __init proc_genhd_init(void)
1318{
1319 proc_create_seq("diskstats", 0, NULL, &diskstats_op);
1320 proc_create_seq("partitions", 0, NULL, &partitions_op);
1321 return 0;
1322}
1323module_init(proc_genhd_init);
1324#endif /* CONFIG_PROC_FS */
1325
1326dev_t part_devt(struct gendisk *disk, u8 partno)
1327{
1328 struct block_device *part;
1329 dev_t devt = 0;
1330
1331 rcu_read_lock();
1332 part = xa_load(&disk->part_tbl, partno);
1333 if (part)
1334 devt = part->bd_dev;
1335 rcu_read_unlock();
1336
1337 return devt;
1338}
1339
1340struct gendisk *__alloc_disk_node(struct request_queue *q, int node_id,
1341 struct lock_class_key *lkclass)
1342{
1343 struct gendisk *disk;
1344
1345 disk = kzalloc_node(sizeof(struct gendisk), GFP_KERNEL, node_id);
1346 if (!disk)
1347 return NULL;
1348
1349 if (bioset_init(&disk->bio_split, BIO_POOL_SIZE, 0, 0))
1350 goto out_free_disk;
1351
1352 disk->bdi = bdi_alloc(node_id);
1353 if (!disk->bdi)
1354 goto out_free_bioset;
1355
1356 /* bdev_alloc() might need the queue, set before the first call */
1357 disk->queue = q;
1358
1359 disk->part0 = bdev_alloc(disk, 0);
1360 if (!disk->part0)
1361 goto out_free_bdi;
1362
1363 disk->node_id = node_id;
1364 mutex_init(&disk->open_mutex);
1365 xa_init(&disk->part_tbl);
1366 if (xa_insert(&disk->part_tbl, 0, disk->part0, GFP_KERNEL))
1367 goto out_destroy_part_tbl;
1368
1369 if (blkcg_init_disk(disk))
1370 goto out_erase_part0;
1371
1372 rand_initialize_disk(disk);
1373 disk_to_dev(disk)->class = &block_class;
1374 disk_to_dev(disk)->type = &disk_type;
1375 device_initialize(disk_to_dev(disk));
1376 inc_diskseq(disk);
1377 q->disk = disk;
1378 lockdep_init_map(&disk->lockdep_map, "(bio completion)", lkclass, 0);
1379#ifdef CONFIG_BLOCK_HOLDER_DEPRECATED
1380 INIT_LIST_HEAD(&disk->slave_bdevs);
1381#endif
1382 return disk;
1383
1384out_erase_part0:
1385 xa_erase(&disk->part_tbl, 0);
1386out_destroy_part_tbl:
1387 xa_destroy(&disk->part_tbl);
1388 disk->part0->bd_disk = NULL;
1389 iput(disk->part0->bd_inode);
1390out_free_bdi:
1391 bdi_put(disk->bdi);
1392out_free_bioset:
1393 bioset_exit(&disk->bio_split);
1394out_free_disk:
1395 kfree(disk);
1396 return NULL;
1397}
1398
1399struct gendisk *__blk_alloc_disk(struct queue_limits *lim, int node,
1400 struct lock_class_key *lkclass)
1401{
1402 struct queue_limits default_lim = { };
1403 struct request_queue *q;
1404 struct gendisk *disk;
1405
1406 q = blk_alloc_queue(lim ? lim : &default_lim, node);
1407 if (IS_ERR(q))
1408 return ERR_CAST(q);
1409
1410 disk = __alloc_disk_node(q, node, lkclass);
1411 if (!disk) {
1412 blk_put_queue(q);
1413 return ERR_PTR(-ENOMEM);
1414 }
1415 set_bit(GD_OWNS_QUEUE, &disk->state);
1416 return disk;
1417}
1418EXPORT_SYMBOL(__blk_alloc_disk);
1419
1420/**
1421 * put_disk - decrements the gendisk refcount
1422 * @disk: the struct gendisk to decrement the refcount for
1423 *
1424 * This decrements the refcount for the struct gendisk. When this reaches 0
1425 * we'll have disk_release() called.
1426 *
1427 * Note: for blk-mq disk put_disk must be called before freeing the tag_set
1428 * when handling probe errors (that is before add_disk() is called).
1429 *
1430 * Context: Any context, but the last reference must not be dropped from
1431 * atomic context.
1432 */
1433void put_disk(struct gendisk *disk)
1434{
1435 if (disk)
1436 put_device(disk_to_dev(disk));
1437}
1438EXPORT_SYMBOL(put_disk);
1439
1440static void set_disk_ro_uevent(struct gendisk *gd, int ro)
1441{
1442 char event[] = "DISK_RO=1";
1443 char *envp[] = { event, NULL };
1444
1445 if (!ro)
1446 event[8] = '0';
1447 kobject_uevent_env(&disk_to_dev(gd)->kobj, KOBJ_CHANGE, envp);
1448}
1449
1450/**
1451 * set_disk_ro - set a gendisk read-only
1452 * @disk: gendisk to operate on
1453 * @read_only: %true to set the disk read-only, %false set the disk read/write
1454 *
1455 * This function is used to indicate whether a given disk device should have its
1456 * read-only flag set. set_disk_ro() is typically used by device drivers to
1457 * indicate whether the underlying physical device is write-protected.
1458 */
1459void set_disk_ro(struct gendisk *disk, bool read_only)
1460{
1461 if (read_only) {
1462 if (test_and_set_bit(GD_READ_ONLY, &disk->state))
1463 return;
1464 } else {
1465 if (!test_and_clear_bit(GD_READ_ONLY, &disk->state))
1466 return;
1467 }
1468 set_disk_ro_uevent(disk, read_only);
1469}
1470EXPORT_SYMBOL(set_disk_ro);
1471
1472void inc_diskseq(struct gendisk *disk)
1473{
1474 disk->diskseq = atomic64_inc_return(&diskseq);
1475}