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