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