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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/mutex.h>
19#include <linux/idr.h>
20#include <linux/log2.h>
21
22#include "blk.h"
23
24static DEFINE_MUTEX(block_class_lock);
25struct kobject *block_depr;
26
27/* for extended dynamic devt allocation, currently only one major is used */
28#define MAX_EXT_DEVT (1 << MINORBITS)
29
30/* For extended devt allocation. ext_devt_mutex prevents look up
31 * results from going away underneath its user.
32 */
33static DEFINE_MUTEX(ext_devt_mutex);
34static DEFINE_IDR(ext_devt_idr);
35
36static struct device_type disk_type;
37
38static void disk_alloc_events(struct gendisk *disk);
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
510static void 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_part_scan_enabled(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 disk_alloc_events(disk);
606
607 /* Register BDI before referencing it from bdev */
608 bdi = &disk->queue->backing_dev_info;
609 bdi_register_dev(bdi, disk_devt(disk));
610
611 blk_register_region(disk_devt(disk), disk->minors, NULL,
612 exact_match, exact_lock, disk);
613 register_disk(disk);
614 blk_register_queue(disk);
615
616 /*
617 * Take an extra ref on queue which will be put on disk_release()
618 * so that it sticks around as long as @disk is there.
619 */
620 WARN_ON_ONCE(!blk_get_queue(disk->queue));
621
622 retval = sysfs_create_link(&disk_to_dev(disk)->kobj, &bdi->dev->kobj,
623 "bdi");
624 WARN_ON(retval);
625
626 disk_add_events(disk);
627}
628EXPORT_SYMBOL(add_disk);
629
630void del_gendisk(struct gendisk *disk)
631{
632 struct disk_part_iter piter;
633 struct hd_struct *part;
634
635 disk_del_events(disk);
636
637 /* invalidate stuff */
638 disk_part_iter_init(&piter, disk,
639 DISK_PITER_INCL_EMPTY | DISK_PITER_REVERSE);
640 while ((part = disk_part_iter_next(&piter))) {
641 invalidate_partition(disk, part->partno);
642 delete_partition(disk, part->partno);
643 }
644 disk_part_iter_exit(&piter);
645
646 invalidate_partition(disk, 0);
647 blk_free_devt(disk_to_dev(disk)->devt);
648 set_capacity(disk, 0);
649 disk->flags &= ~GENHD_FL_UP;
650
651 sysfs_remove_link(&disk_to_dev(disk)->kobj, "bdi");
652 bdi_unregister(&disk->queue->backing_dev_info);
653 blk_unregister_queue(disk);
654 blk_unregister_region(disk_devt(disk), disk->minors);
655
656 part_stat_set_all(&disk->part0, 0);
657 disk->part0.stamp = 0;
658
659 kobject_put(disk->part0.holder_dir);
660 kobject_put(disk->slave_dir);
661 disk->driverfs_dev = NULL;
662 if (!sysfs_deprecated)
663 sysfs_remove_link(block_depr, dev_name(disk_to_dev(disk)));
664 device_del(disk_to_dev(disk));
665}
666EXPORT_SYMBOL(del_gendisk);
667
668/**
669 * get_gendisk - get partitioning information for a given device
670 * @devt: device to get partitioning information for
671 * @partno: returned partition index
672 *
673 * This function gets the structure containing partitioning
674 * information for the given device @devt.
675 */
676struct gendisk *get_gendisk(dev_t devt, int *partno)
677{
678 struct gendisk *disk = NULL;
679
680 if (MAJOR(devt) != BLOCK_EXT_MAJOR) {
681 struct kobject *kobj;
682
683 kobj = kobj_lookup(bdev_map, devt, partno);
684 if (kobj)
685 disk = dev_to_disk(kobj_to_dev(kobj));
686 } else {
687 struct hd_struct *part;
688
689 mutex_lock(&ext_devt_mutex);
690 part = idr_find(&ext_devt_idr, blk_mangle_minor(MINOR(devt)));
691 if (part && get_disk(part_to_disk(part))) {
692 *partno = part->partno;
693 disk = part_to_disk(part);
694 }
695 mutex_unlock(&ext_devt_mutex);
696 }
697
698 return disk;
699}
700EXPORT_SYMBOL(get_gendisk);
701
702/**
703 * bdget_disk - do bdget() by gendisk and partition number
704 * @disk: gendisk of interest
705 * @partno: partition number
706 *
707 * Find partition @partno from @disk, do bdget() on it.
708 *
709 * CONTEXT:
710 * Don't care.
711 *
712 * RETURNS:
713 * Resulting block_device on success, NULL on failure.
714 */
715struct block_device *bdget_disk(struct gendisk *disk, int partno)
716{
717 struct hd_struct *part;
718 struct block_device *bdev = NULL;
719
720 part = disk_get_part(disk, partno);
721 if (part)
722 bdev = bdget(part_devt(part));
723 disk_put_part(part);
724
725 return bdev;
726}
727EXPORT_SYMBOL(bdget_disk);
728
729/*
730 * print a full list of all partitions - intended for places where the root
731 * filesystem can't be mounted and thus to give the victim some idea of what
732 * went wrong
733 */
734void __init printk_all_partitions(void)
735{
736 struct class_dev_iter iter;
737 struct device *dev;
738
739 class_dev_iter_init(&iter, &block_class, NULL, &disk_type);
740 while ((dev = class_dev_iter_next(&iter))) {
741 struct gendisk *disk = dev_to_disk(dev);
742 struct disk_part_iter piter;
743 struct hd_struct *part;
744 char name_buf[BDEVNAME_SIZE];
745 char devt_buf[BDEVT_SIZE];
746 char uuid_buf[PARTITION_META_INFO_UUIDLTH * 2 + 5];
747
748 /*
749 * Don't show empty devices or things that have been
750 * suppressed
751 */
752 if (get_capacity(disk) == 0 ||
753 (disk->flags & GENHD_FL_SUPPRESS_PARTITION_INFO))
754 continue;
755
756 /*
757 * Note, unlike /proc/partitions, I am showing the
758 * numbers in hex - the same format as the root=
759 * option takes.
760 */
761 disk_part_iter_init(&piter, disk, DISK_PITER_INCL_PART0);
762 while ((part = disk_part_iter_next(&piter))) {
763 bool is_part0 = part == &disk->part0;
764
765 uuid_buf[0] = '\0';
766 if (part->info)
767 snprintf(uuid_buf, sizeof(uuid_buf), "%pU",
768 part->info->uuid);
769
770 printk("%s%s %10llu %s %s", is_part0 ? "" : " ",
771 bdevt_str(part_devt(part), devt_buf),
772 (unsigned long long)part->nr_sects >> 1,
773 disk_name(disk, part->partno, name_buf),
774 uuid_buf);
775 if (is_part0) {
776 if (disk->driverfs_dev != NULL &&
777 disk->driverfs_dev->driver != NULL)
778 printk(" driver: %s\n",
779 disk->driverfs_dev->driver->name);
780 else
781 printk(" (driver?)\n");
782 } else
783 printk("\n");
784 }
785 disk_part_iter_exit(&piter);
786 }
787 class_dev_iter_exit(&iter);
788}
789
790#ifdef CONFIG_PROC_FS
791/* iterator */
792static void *disk_seqf_start(struct seq_file *seqf, loff_t *pos)
793{
794 loff_t skip = *pos;
795 struct class_dev_iter *iter;
796 struct device *dev;
797
798 iter = kmalloc(sizeof(*iter), GFP_KERNEL);
799 if (!iter)
800 return ERR_PTR(-ENOMEM);
801
802 seqf->private = iter;
803 class_dev_iter_init(iter, &block_class, NULL, &disk_type);
804 do {
805 dev = class_dev_iter_next(iter);
806 if (!dev)
807 return NULL;
808 } while (skip--);
809
810 return dev_to_disk(dev);
811}
812
813static void *disk_seqf_next(struct seq_file *seqf, void *v, loff_t *pos)
814{
815 struct device *dev;
816
817 (*pos)++;
818 dev = class_dev_iter_next(seqf->private);
819 if (dev)
820 return dev_to_disk(dev);
821
822 return NULL;
823}
824
825static void disk_seqf_stop(struct seq_file *seqf, void *v)
826{
827 struct class_dev_iter *iter = seqf->private;
828
829 /* stop is called even after start failed :-( */
830 if (iter) {
831 class_dev_iter_exit(iter);
832 kfree(iter);
833 }
834}
835
836static void *show_partition_start(struct seq_file *seqf, loff_t *pos)
837{
838 static void *p;
839
840 p = disk_seqf_start(seqf, pos);
841 if (!IS_ERR_OR_NULL(p) && !*pos)
842 seq_puts(seqf, "major minor #blocks name\n\n");
843 return p;
844}
845
846static int show_partition(struct seq_file *seqf, void *v)
847{
848 struct gendisk *sgp = v;
849 struct disk_part_iter piter;
850 struct hd_struct *part;
851 char buf[BDEVNAME_SIZE];
852
853 /* Don't show non-partitionable removeable devices or empty devices */
854 if (!get_capacity(sgp) || (!disk_max_parts(sgp) &&
855 (sgp->flags & GENHD_FL_REMOVABLE)))
856 return 0;
857 if (sgp->flags & GENHD_FL_SUPPRESS_PARTITION_INFO)
858 return 0;
859
860 /* show the full disk and all non-0 size partitions of it */
861 disk_part_iter_init(&piter, sgp, DISK_PITER_INCL_PART0);
862 while ((part = disk_part_iter_next(&piter)))
863 seq_printf(seqf, "%4d %7d %10llu %s\n",
864 MAJOR(part_devt(part)), MINOR(part_devt(part)),
865 (unsigned long long)part->nr_sects >> 1,
866 disk_name(sgp, part->partno, buf));
867 disk_part_iter_exit(&piter);
868
869 return 0;
870}
871
872static const struct seq_operations partitions_op = {
873 .start = show_partition_start,
874 .next = disk_seqf_next,
875 .stop = disk_seqf_stop,
876 .show = show_partition
877};
878
879static int partitions_open(struct inode *inode, struct file *file)
880{
881 return seq_open(file, &partitions_op);
882}
883
884static const struct file_operations proc_partitions_operations = {
885 .open = partitions_open,
886 .read = seq_read,
887 .llseek = seq_lseek,
888 .release = seq_release,
889};
890#endif
891
892
893static struct kobject *base_probe(dev_t devt, int *partno, void *data)
894{
895 if (request_module("block-major-%d-%d", MAJOR(devt), MINOR(devt)) > 0)
896 /* Make old-style 2.4 aliases work */
897 request_module("block-major-%d", MAJOR(devt));
898 return NULL;
899}
900
901static int __init genhd_device_init(void)
902{
903 int error;
904
905 block_class.dev_kobj = sysfs_dev_block_kobj;
906 error = class_register(&block_class);
907 if (unlikely(error))
908 return error;
909 bdev_map = kobj_map_init(base_probe, &block_class_lock);
910 blk_dev_init();
911
912 register_blkdev(BLOCK_EXT_MAJOR, "blkext");
913
914 /* create top-level block dir */
915 if (!sysfs_deprecated)
916 block_depr = kobject_create_and_add("block", NULL);
917 return 0;
918}
919
920subsys_initcall(genhd_device_init);
921
922static ssize_t disk_range_show(struct device *dev,
923 struct device_attribute *attr, char *buf)
924{
925 struct gendisk *disk = dev_to_disk(dev);
926
927 return sprintf(buf, "%d\n", disk->minors);
928}
929
930static ssize_t disk_ext_range_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", disk_max_parts(disk));
936}
937
938static ssize_t disk_removable_show(struct device *dev,
939 struct device_attribute *attr, char *buf)
940{
941 struct gendisk *disk = dev_to_disk(dev);
942
943 return sprintf(buf, "%d\n",
944 (disk->flags & GENHD_FL_REMOVABLE ? 1 : 0));
945}
946
947static ssize_t disk_ro_show(struct device *dev,
948 struct device_attribute *attr, char *buf)
949{
950 struct gendisk *disk = dev_to_disk(dev);
951
952 return sprintf(buf, "%d\n", get_disk_ro(disk) ? 1 : 0);
953}
954
955static ssize_t disk_capability_show(struct device *dev,
956 struct device_attribute *attr, char *buf)
957{
958 struct gendisk *disk = dev_to_disk(dev);
959
960 return sprintf(buf, "%x\n", disk->flags);
961}
962
963static ssize_t disk_alignment_offset_show(struct device *dev,
964 struct device_attribute *attr,
965 char *buf)
966{
967 struct gendisk *disk = dev_to_disk(dev);
968
969 return sprintf(buf, "%d\n", queue_alignment_offset(disk->queue));
970}
971
972static ssize_t disk_discard_alignment_show(struct device *dev,
973 struct device_attribute *attr,
974 char *buf)
975{
976 struct gendisk *disk = dev_to_disk(dev);
977
978 return sprintf(buf, "%d\n", queue_discard_alignment(disk->queue));
979}
980
981static DEVICE_ATTR(range, S_IRUGO, disk_range_show, NULL);
982static DEVICE_ATTR(ext_range, S_IRUGO, disk_ext_range_show, NULL);
983static DEVICE_ATTR(removable, S_IRUGO, disk_removable_show, NULL);
984static DEVICE_ATTR(ro, S_IRUGO, disk_ro_show, NULL);
985static DEVICE_ATTR(size, S_IRUGO, part_size_show, NULL);
986static DEVICE_ATTR(alignment_offset, S_IRUGO, disk_alignment_offset_show, NULL);
987static DEVICE_ATTR(discard_alignment, S_IRUGO, disk_discard_alignment_show,
988 NULL);
989static DEVICE_ATTR(capability, S_IRUGO, disk_capability_show, NULL);
990static DEVICE_ATTR(stat, S_IRUGO, part_stat_show, NULL);
991static DEVICE_ATTR(inflight, S_IRUGO, part_inflight_show, NULL);
992#ifdef CONFIG_FAIL_MAKE_REQUEST
993static struct device_attribute dev_attr_fail =
994 __ATTR(make-it-fail, S_IRUGO|S_IWUSR, part_fail_show, part_fail_store);
995#endif
996#ifdef CONFIG_FAIL_IO_TIMEOUT
997static struct device_attribute dev_attr_fail_timeout =
998 __ATTR(io-timeout-fail, S_IRUGO|S_IWUSR, part_timeout_show,
999 part_timeout_store);
1000#endif
1001
1002static struct attribute *disk_attrs[] = {
1003 &dev_attr_range.attr,
1004 &dev_attr_ext_range.attr,
1005 &dev_attr_removable.attr,
1006 &dev_attr_ro.attr,
1007 &dev_attr_size.attr,
1008 &dev_attr_alignment_offset.attr,
1009 &dev_attr_discard_alignment.attr,
1010 &dev_attr_capability.attr,
1011 &dev_attr_stat.attr,
1012 &dev_attr_inflight.attr,
1013#ifdef CONFIG_FAIL_MAKE_REQUEST
1014 &dev_attr_fail.attr,
1015#endif
1016#ifdef CONFIG_FAIL_IO_TIMEOUT
1017 &dev_attr_fail_timeout.attr,
1018#endif
1019 NULL
1020};
1021
1022static struct attribute_group disk_attr_group = {
1023 .attrs = disk_attrs,
1024};
1025
1026static const struct attribute_group *disk_attr_groups[] = {
1027 &disk_attr_group,
1028 NULL
1029};
1030
1031/**
1032 * disk_replace_part_tbl - replace disk->part_tbl in RCU-safe way
1033 * @disk: disk to replace part_tbl for
1034 * @new_ptbl: new part_tbl to install
1035 *
1036 * Replace disk->part_tbl with @new_ptbl in RCU-safe way. The
1037 * original ptbl is freed using RCU callback.
1038 *
1039 * LOCKING:
1040 * Matching bd_mutx locked.
1041 */
1042static void disk_replace_part_tbl(struct gendisk *disk,
1043 struct disk_part_tbl *new_ptbl)
1044{
1045 struct disk_part_tbl *old_ptbl = disk->part_tbl;
1046
1047 rcu_assign_pointer(disk->part_tbl, new_ptbl);
1048
1049 if (old_ptbl) {
1050 rcu_assign_pointer(old_ptbl->last_lookup, NULL);
1051 kfree_rcu(old_ptbl, rcu_head);
1052 }
1053}
1054
1055/**
1056 * disk_expand_part_tbl - expand disk->part_tbl
1057 * @disk: disk to expand part_tbl for
1058 * @partno: expand such that this partno can fit in
1059 *
1060 * Expand disk->part_tbl such that @partno can fit in. disk->part_tbl
1061 * uses RCU to allow unlocked dereferencing for stats and other stuff.
1062 *
1063 * LOCKING:
1064 * Matching bd_mutex locked, might sleep.
1065 *
1066 * RETURNS:
1067 * 0 on success, -errno on failure.
1068 */
1069int disk_expand_part_tbl(struct gendisk *disk, int partno)
1070{
1071 struct disk_part_tbl *old_ptbl = disk->part_tbl;
1072 struct disk_part_tbl *new_ptbl;
1073 int len = old_ptbl ? old_ptbl->len : 0;
1074 int target = partno + 1;
1075 size_t size;
1076 int i;
1077
1078 /* disk_max_parts() is zero during initialization, ignore if so */
1079 if (disk_max_parts(disk) && target > disk_max_parts(disk))
1080 return -EINVAL;
1081
1082 if (target <= len)
1083 return 0;
1084
1085 size = sizeof(*new_ptbl) + target * sizeof(new_ptbl->part[0]);
1086 new_ptbl = kzalloc_node(size, GFP_KERNEL, disk->node_id);
1087 if (!new_ptbl)
1088 return -ENOMEM;
1089
1090 new_ptbl->len = target;
1091
1092 for (i = 0; i < len; i++)
1093 rcu_assign_pointer(new_ptbl->part[i], old_ptbl->part[i]);
1094
1095 disk_replace_part_tbl(disk, new_ptbl);
1096 return 0;
1097}
1098
1099static void disk_release(struct device *dev)
1100{
1101 struct gendisk *disk = dev_to_disk(dev);
1102
1103 disk_release_events(disk);
1104 kfree(disk->random);
1105 disk_replace_part_tbl(disk, NULL);
1106 free_part_stats(&disk->part0);
1107 free_part_info(&disk->part0);
1108 if (disk->queue)
1109 blk_put_queue(disk->queue);
1110 kfree(disk);
1111}
1112struct class block_class = {
1113 .name = "block",
1114};
1115
1116static char *block_devnode(struct device *dev, umode_t *mode)
1117{
1118 struct gendisk *disk = dev_to_disk(dev);
1119
1120 if (disk->devnode)
1121 return disk->devnode(disk, mode);
1122 return NULL;
1123}
1124
1125static struct device_type disk_type = {
1126 .name = "disk",
1127 .groups = disk_attr_groups,
1128 .release = disk_release,
1129 .devnode = block_devnode,
1130};
1131
1132#ifdef CONFIG_PROC_FS
1133/*
1134 * aggregate disk stat collector. Uses the same stats that the sysfs
1135 * entries do, above, but makes them available through one seq_file.
1136 *
1137 * The output looks suspiciously like /proc/partitions with a bunch of
1138 * extra fields.
1139 */
1140static int diskstats_show(struct seq_file *seqf, void *v)
1141{
1142 struct gendisk *gp = v;
1143 struct disk_part_iter piter;
1144 struct hd_struct *hd;
1145 char buf[BDEVNAME_SIZE];
1146 int cpu;
1147
1148 /*
1149 if (&disk_to_dev(gp)->kobj.entry == block_class.devices.next)
1150 seq_puts(seqf, "major minor name"
1151 " rio rmerge rsect ruse wio wmerge "
1152 "wsect wuse running use aveq"
1153 "\n\n");
1154 */
1155
1156 disk_part_iter_init(&piter, gp, DISK_PITER_INCL_EMPTY_PART0);
1157 while ((hd = disk_part_iter_next(&piter))) {
1158 cpu = part_stat_lock();
1159 part_round_stats(cpu, hd);
1160 part_stat_unlock();
1161 seq_printf(seqf, "%4d %7d %s %lu %lu %lu "
1162 "%u %lu %lu %lu %u %u %u %u\n",
1163 MAJOR(part_devt(hd)), MINOR(part_devt(hd)),
1164 disk_name(gp, hd->partno, buf),
1165 part_stat_read(hd, ios[READ]),
1166 part_stat_read(hd, merges[READ]),
1167 part_stat_read(hd, sectors[READ]),
1168 jiffies_to_msecs(part_stat_read(hd, ticks[READ])),
1169 part_stat_read(hd, ios[WRITE]),
1170 part_stat_read(hd, merges[WRITE]),
1171 part_stat_read(hd, sectors[WRITE]),
1172 jiffies_to_msecs(part_stat_read(hd, ticks[WRITE])),
1173 part_in_flight(hd),
1174 jiffies_to_msecs(part_stat_read(hd, io_ticks)),
1175 jiffies_to_msecs(part_stat_read(hd, time_in_queue))
1176 );
1177 }
1178 disk_part_iter_exit(&piter);
1179
1180 return 0;
1181}
1182
1183static const struct seq_operations diskstats_op = {
1184 .start = disk_seqf_start,
1185 .next = disk_seqf_next,
1186 .stop = disk_seqf_stop,
1187 .show = diskstats_show
1188};
1189
1190static int diskstats_open(struct inode *inode, struct file *file)
1191{
1192 return seq_open(file, &diskstats_op);
1193}
1194
1195static const struct file_operations proc_diskstats_operations = {
1196 .open = diskstats_open,
1197 .read = seq_read,
1198 .llseek = seq_lseek,
1199 .release = seq_release,
1200};
1201
1202static int __init proc_genhd_init(void)
1203{
1204 proc_create("diskstats", 0, NULL, &proc_diskstats_operations);
1205 proc_create("partitions", 0, NULL, &proc_partitions_operations);
1206 return 0;
1207}
1208module_init(proc_genhd_init);
1209#endif /* CONFIG_PROC_FS */
1210
1211dev_t blk_lookup_devt(const char *name, int partno)
1212{
1213 dev_t devt = MKDEV(0, 0);
1214 struct class_dev_iter iter;
1215 struct device *dev;
1216
1217 class_dev_iter_init(&iter, &block_class, NULL, &disk_type);
1218 while ((dev = class_dev_iter_next(&iter))) {
1219 struct gendisk *disk = dev_to_disk(dev);
1220 struct hd_struct *part;
1221
1222 if (strcmp(dev_name(dev), name))
1223 continue;
1224
1225 if (partno < disk->minors) {
1226 /* We need to return the right devno, even
1227 * if the partition doesn't exist yet.
1228 */
1229 devt = MKDEV(MAJOR(dev->devt),
1230 MINOR(dev->devt) + partno);
1231 break;
1232 }
1233 part = disk_get_part(disk, partno);
1234 if (part) {
1235 devt = part_devt(part);
1236 disk_put_part(part);
1237 break;
1238 }
1239 disk_put_part(part);
1240 }
1241 class_dev_iter_exit(&iter);
1242 return devt;
1243}
1244EXPORT_SYMBOL(blk_lookup_devt);
1245
1246struct gendisk *alloc_disk(int minors)
1247{
1248 return alloc_disk_node(minors, -1);
1249}
1250EXPORT_SYMBOL(alloc_disk);
1251
1252struct gendisk *alloc_disk_node(int minors, int node_id)
1253{
1254 struct gendisk *disk;
1255
1256 disk = kmalloc_node(sizeof(struct gendisk),
1257 GFP_KERNEL | __GFP_ZERO, node_id);
1258 if (disk) {
1259 if (!init_part_stats(&disk->part0)) {
1260 kfree(disk);
1261 return NULL;
1262 }
1263 disk->node_id = node_id;
1264 if (disk_expand_part_tbl(disk, 0)) {
1265 free_part_stats(&disk->part0);
1266 kfree(disk);
1267 return NULL;
1268 }
1269 disk->part_tbl->part[0] = &disk->part0;
1270
1271 hd_ref_init(&disk->part0);
1272
1273 disk->minors = minors;
1274 rand_initialize_disk(disk);
1275 disk_to_dev(disk)->class = &block_class;
1276 disk_to_dev(disk)->type = &disk_type;
1277 device_initialize(disk_to_dev(disk));
1278 }
1279 return disk;
1280}
1281EXPORT_SYMBOL(alloc_disk_node);
1282
1283struct kobject *get_disk(struct gendisk *disk)
1284{
1285 struct module *owner;
1286 struct kobject *kobj;
1287
1288 if (!disk->fops)
1289 return NULL;
1290 owner = disk->fops->owner;
1291 if (owner && !try_module_get(owner))
1292 return NULL;
1293 kobj = kobject_get(&disk_to_dev(disk)->kobj);
1294 if (kobj == NULL) {
1295 module_put(owner);
1296 return NULL;
1297 }
1298 return kobj;
1299
1300}
1301
1302EXPORT_SYMBOL(get_disk);
1303
1304void put_disk(struct gendisk *disk)
1305{
1306 if (disk)
1307 kobject_put(&disk_to_dev(disk)->kobj);
1308}
1309
1310EXPORT_SYMBOL(put_disk);
1311
1312static void set_disk_ro_uevent(struct gendisk *gd, int ro)
1313{
1314 char event[] = "DISK_RO=1";
1315 char *envp[] = { event, NULL };
1316
1317 if (!ro)
1318 event[8] = '0';
1319 kobject_uevent_env(&disk_to_dev(gd)->kobj, KOBJ_CHANGE, envp);
1320}
1321
1322void set_device_ro(struct block_device *bdev, int flag)
1323{
1324 bdev->bd_part->policy = flag;
1325}
1326
1327EXPORT_SYMBOL(set_device_ro);
1328
1329void set_disk_ro(struct gendisk *disk, int flag)
1330{
1331 struct disk_part_iter piter;
1332 struct hd_struct *part;
1333
1334 if (disk->part0.policy != flag) {
1335 set_disk_ro_uevent(disk, flag);
1336 disk->part0.policy = flag;
1337 }
1338
1339 disk_part_iter_init(&piter, disk, DISK_PITER_INCL_EMPTY);
1340 while ((part = disk_part_iter_next(&piter)))
1341 part->policy = flag;
1342 disk_part_iter_exit(&piter);
1343}
1344
1345EXPORT_SYMBOL(set_disk_ro);
1346
1347int bdev_read_only(struct block_device *bdev)
1348{
1349 if (!bdev)
1350 return 0;
1351 return bdev->bd_part->policy;
1352}
1353
1354EXPORT_SYMBOL(bdev_read_only);
1355
1356int invalidate_partition(struct gendisk *disk, int partno)
1357{
1358 int res = 0;
1359 struct block_device *bdev = bdget_disk(disk, partno);
1360 if (bdev) {
1361 fsync_bdev(bdev);
1362 res = __invalidate_device(bdev, true);
1363 bdput(bdev);
1364 }
1365 return res;
1366}
1367
1368EXPORT_SYMBOL(invalidate_partition);
1369
1370/*
1371 * Disk events - monitor disk events like media change and eject request.
1372 */
1373struct disk_events {
1374 struct list_head node; /* all disk_event's */
1375 struct gendisk *disk; /* the associated disk */
1376 spinlock_t lock;
1377
1378 struct mutex block_mutex; /* protects blocking */
1379 int block; /* event blocking depth */
1380 unsigned int pending; /* events already sent out */
1381 unsigned int clearing; /* events being cleared */
1382
1383 long poll_msecs; /* interval, -1 for default */
1384 struct delayed_work dwork;
1385};
1386
1387static const char *disk_events_strs[] = {
1388 [ilog2(DISK_EVENT_MEDIA_CHANGE)] = "media_change",
1389 [ilog2(DISK_EVENT_EJECT_REQUEST)] = "eject_request",
1390};
1391
1392static char *disk_uevents[] = {
1393 [ilog2(DISK_EVENT_MEDIA_CHANGE)] = "DISK_MEDIA_CHANGE=1",
1394 [ilog2(DISK_EVENT_EJECT_REQUEST)] = "DISK_EJECT_REQUEST=1",
1395};
1396
1397/* list of all disk_events */
1398static DEFINE_MUTEX(disk_events_mutex);
1399static LIST_HEAD(disk_events);
1400
1401/* disable in-kernel polling by default */
1402static unsigned long disk_events_dfl_poll_msecs = 0;
1403
1404static unsigned long disk_events_poll_jiffies(struct gendisk *disk)
1405{
1406 struct disk_events *ev = disk->ev;
1407 long intv_msecs = 0;
1408
1409 /*
1410 * If device-specific poll interval is set, always use it. If
1411 * the default is being used, poll iff there are events which
1412 * can't be monitored asynchronously.
1413 */
1414 if (ev->poll_msecs >= 0)
1415 intv_msecs = ev->poll_msecs;
1416 else if (disk->events & ~disk->async_events)
1417 intv_msecs = disk_events_dfl_poll_msecs;
1418
1419 return msecs_to_jiffies(intv_msecs);
1420}
1421
1422/**
1423 * disk_block_events - block and flush disk event checking
1424 * @disk: disk to block events for
1425 *
1426 * On return from this function, it is guaranteed that event checking
1427 * isn't in progress and won't happen until unblocked by
1428 * disk_unblock_events(). Events blocking is counted and the actual
1429 * unblocking happens after the matching number of unblocks are done.
1430 *
1431 * Note that this intentionally does not block event checking from
1432 * disk_clear_events().
1433 *
1434 * CONTEXT:
1435 * Might sleep.
1436 */
1437void disk_block_events(struct gendisk *disk)
1438{
1439 struct disk_events *ev = disk->ev;
1440 unsigned long flags;
1441 bool cancel;
1442
1443 if (!ev)
1444 return;
1445
1446 /*
1447 * Outer mutex ensures that the first blocker completes canceling
1448 * the event work before further blockers are allowed to finish.
1449 */
1450 mutex_lock(&ev->block_mutex);
1451
1452 spin_lock_irqsave(&ev->lock, flags);
1453 cancel = !ev->block++;
1454 spin_unlock_irqrestore(&ev->lock, flags);
1455
1456 if (cancel)
1457 cancel_delayed_work_sync(&disk->ev->dwork);
1458
1459 mutex_unlock(&ev->block_mutex);
1460}
1461
1462static void __disk_unblock_events(struct gendisk *disk, bool check_now)
1463{
1464 struct disk_events *ev = disk->ev;
1465 unsigned long intv;
1466 unsigned long flags;
1467
1468 spin_lock_irqsave(&ev->lock, flags);
1469
1470 if (WARN_ON_ONCE(ev->block <= 0))
1471 goto out_unlock;
1472
1473 if (--ev->block)
1474 goto out_unlock;
1475
1476 /*
1477 * Not exactly a latency critical operation, set poll timer
1478 * slack to 25% and kick event check.
1479 */
1480 intv = disk_events_poll_jiffies(disk);
1481 set_timer_slack(&ev->dwork.timer, intv / 4);
1482 if (check_now)
1483 queue_delayed_work(system_nrt_freezable_wq, &ev->dwork, 0);
1484 else if (intv)
1485 queue_delayed_work(system_nrt_freezable_wq, &ev->dwork, intv);
1486out_unlock:
1487 spin_unlock_irqrestore(&ev->lock, flags);
1488}
1489
1490/**
1491 * disk_unblock_events - unblock disk event checking
1492 * @disk: disk to unblock events for
1493 *
1494 * Undo disk_block_events(). When the block count reaches zero, it
1495 * starts events polling if configured.
1496 *
1497 * CONTEXT:
1498 * Don't care. Safe to call from irq context.
1499 */
1500void disk_unblock_events(struct gendisk *disk)
1501{
1502 if (disk->ev)
1503 __disk_unblock_events(disk, false);
1504}
1505
1506/**
1507 * disk_flush_events - schedule immediate event checking and flushing
1508 * @disk: disk to check and flush events for
1509 * @mask: events to flush
1510 *
1511 * Schedule immediate event checking on @disk if not blocked. Events in
1512 * @mask are scheduled to be cleared from the driver. Note that this
1513 * doesn't clear the events from @disk->ev.
1514 *
1515 * CONTEXT:
1516 * If @mask is non-zero must be called with bdev->bd_mutex held.
1517 */
1518void disk_flush_events(struct gendisk *disk, unsigned int mask)
1519{
1520 struct disk_events *ev = disk->ev;
1521
1522 if (!ev)
1523 return;
1524
1525 spin_lock_irq(&ev->lock);
1526 ev->clearing |= mask;
1527 if (!ev->block) {
1528 cancel_delayed_work(&ev->dwork);
1529 queue_delayed_work(system_nrt_freezable_wq, &ev->dwork, 0);
1530 }
1531 spin_unlock_irq(&ev->lock);
1532}
1533
1534/**
1535 * disk_clear_events - synchronously check, clear and return pending events
1536 * @disk: disk to fetch and clear events from
1537 * @mask: mask of events to be fetched and clearted
1538 *
1539 * Disk events are synchronously checked and pending events in @mask
1540 * are cleared and returned. This ignores the block count.
1541 *
1542 * CONTEXT:
1543 * Might sleep.
1544 */
1545unsigned int disk_clear_events(struct gendisk *disk, unsigned int mask)
1546{
1547 const struct block_device_operations *bdops = disk->fops;
1548 struct disk_events *ev = disk->ev;
1549 unsigned int pending;
1550
1551 if (!ev) {
1552 /* for drivers still using the old ->media_changed method */
1553 if ((mask & DISK_EVENT_MEDIA_CHANGE) &&
1554 bdops->media_changed && bdops->media_changed(disk))
1555 return DISK_EVENT_MEDIA_CHANGE;
1556 return 0;
1557 }
1558
1559 /* tell the workfn about the events being cleared */
1560 spin_lock_irq(&ev->lock);
1561 ev->clearing |= mask;
1562 spin_unlock_irq(&ev->lock);
1563
1564 /* uncondtionally schedule event check and wait for it to finish */
1565 disk_block_events(disk);
1566 queue_delayed_work(system_nrt_freezable_wq, &ev->dwork, 0);
1567 flush_delayed_work(&ev->dwork);
1568 __disk_unblock_events(disk, false);
1569
1570 /* then, fetch and clear pending events */
1571 spin_lock_irq(&ev->lock);
1572 WARN_ON_ONCE(ev->clearing & mask); /* cleared by workfn */
1573 pending = ev->pending & mask;
1574 ev->pending &= ~mask;
1575 spin_unlock_irq(&ev->lock);
1576
1577 return pending;
1578}
1579
1580static void disk_events_workfn(struct work_struct *work)
1581{
1582 struct delayed_work *dwork = to_delayed_work(work);
1583 struct disk_events *ev = container_of(dwork, struct disk_events, dwork);
1584 struct gendisk *disk = ev->disk;
1585 char *envp[ARRAY_SIZE(disk_uevents) + 1] = { };
1586 unsigned int clearing = ev->clearing;
1587 unsigned int events;
1588 unsigned long intv;
1589 int nr_events = 0, i;
1590
1591 /* check events */
1592 events = disk->fops->check_events(disk, clearing);
1593
1594 /* accumulate pending events and schedule next poll if necessary */
1595 spin_lock_irq(&ev->lock);
1596
1597 events &= ~ev->pending;
1598 ev->pending |= events;
1599 ev->clearing &= ~clearing;
1600
1601 intv = disk_events_poll_jiffies(disk);
1602 if (!ev->block && intv)
1603 queue_delayed_work(system_nrt_freezable_wq, &ev->dwork, intv);
1604
1605 spin_unlock_irq(&ev->lock);
1606
1607 /*
1608 * Tell userland about new events. Only the events listed in
1609 * @disk->events are reported. Unlisted events are processed the
1610 * same internally but never get reported to userland.
1611 */
1612 for (i = 0; i < ARRAY_SIZE(disk_uevents); i++)
1613 if (events & disk->events & (1 << i))
1614 envp[nr_events++] = disk_uevents[i];
1615
1616 if (nr_events)
1617 kobject_uevent_env(&disk_to_dev(disk)->kobj, KOBJ_CHANGE, envp);
1618}
1619
1620/*
1621 * A disk events enabled device has the following sysfs nodes under
1622 * its /sys/block/X/ directory.
1623 *
1624 * events : list of all supported events
1625 * events_async : list of events which can be detected w/o polling
1626 * events_poll_msecs : polling interval, 0: disable, -1: system default
1627 */
1628static ssize_t __disk_events_show(unsigned int events, char *buf)
1629{
1630 const char *delim = "";
1631 ssize_t pos = 0;
1632 int i;
1633
1634 for (i = 0; i < ARRAY_SIZE(disk_events_strs); i++)
1635 if (events & (1 << i)) {
1636 pos += sprintf(buf + pos, "%s%s",
1637 delim, disk_events_strs[i]);
1638 delim = " ";
1639 }
1640 if (pos)
1641 pos += sprintf(buf + pos, "\n");
1642 return pos;
1643}
1644
1645static ssize_t disk_events_show(struct device *dev,
1646 struct device_attribute *attr, char *buf)
1647{
1648 struct gendisk *disk = dev_to_disk(dev);
1649
1650 return __disk_events_show(disk->events, buf);
1651}
1652
1653static ssize_t disk_events_async_show(struct device *dev,
1654 struct device_attribute *attr, char *buf)
1655{
1656 struct gendisk *disk = dev_to_disk(dev);
1657
1658 return __disk_events_show(disk->async_events, buf);
1659}
1660
1661static ssize_t disk_events_poll_msecs_show(struct device *dev,
1662 struct device_attribute *attr,
1663 char *buf)
1664{
1665 struct gendisk *disk = dev_to_disk(dev);
1666
1667 return sprintf(buf, "%ld\n", disk->ev->poll_msecs);
1668}
1669
1670static ssize_t disk_events_poll_msecs_store(struct device *dev,
1671 struct device_attribute *attr,
1672 const char *buf, size_t count)
1673{
1674 struct gendisk *disk = dev_to_disk(dev);
1675 long intv;
1676
1677 if (!count || !sscanf(buf, "%ld", &intv))
1678 return -EINVAL;
1679
1680 if (intv < 0 && intv != -1)
1681 return -EINVAL;
1682
1683 disk_block_events(disk);
1684 disk->ev->poll_msecs = intv;
1685 __disk_unblock_events(disk, true);
1686
1687 return count;
1688}
1689
1690static const DEVICE_ATTR(events, S_IRUGO, disk_events_show, NULL);
1691static const DEVICE_ATTR(events_async, S_IRUGO, disk_events_async_show, NULL);
1692static const DEVICE_ATTR(events_poll_msecs, S_IRUGO|S_IWUSR,
1693 disk_events_poll_msecs_show,
1694 disk_events_poll_msecs_store);
1695
1696static const struct attribute *disk_events_attrs[] = {
1697 &dev_attr_events.attr,
1698 &dev_attr_events_async.attr,
1699 &dev_attr_events_poll_msecs.attr,
1700 NULL,
1701};
1702
1703/*
1704 * The default polling interval can be specified by the kernel
1705 * parameter block.events_dfl_poll_msecs which defaults to 0
1706 * (disable). This can also be modified runtime by writing to
1707 * /sys/module/block/events_dfl_poll_msecs.
1708 */
1709static int disk_events_set_dfl_poll_msecs(const char *val,
1710 const struct kernel_param *kp)
1711{
1712 struct disk_events *ev;
1713 int ret;
1714
1715 ret = param_set_ulong(val, kp);
1716 if (ret < 0)
1717 return ret;
1718
1719 mutex_lock(&disk_events_mutex);
1720
1721 list_for_each_entry(ev, &disk_events, node)
1722 disk_flush_events(ev->disk, 0);
1723
1724 mutex_unlock(&disk_events_mutex);
1725
1726 return 0;
1727}
1728
1729static const struct kernel_param_ops disk_events_dfl_poll_msecs_param_ops = {
1730 .set = disk_events_set_dfl_poll_msecs,
1731 .get = param_get_ulong,
1732};
1733
1734#undef MODULE_PARAM_PREFIX
1735#define MODULE_PARAM_PREFIX "block."
1736
1737module_param_cb(events_dfl_poll_msecs, &disk_events_dfl_poll_msecs_param_ops,
1738 &disk_events_dfl_poll_msecs, 0644);
1739
1740/*
1741 * disk_{alloc|add|del|release}_events - initialize and destroy disk_events.
1742 */
1743static void disk_alloc_events(struct gendisk *disk)
1744{
1745 struct disk_events *ev;
1746
1747 if (!disk->fops->check_events)
1748 return;
1749
1750 ev = kzalloc(sizeof(*ev), GFP_KERNEL);
1751 if (!ev) {
1752 pr_warn("%s: failed to initialize events\n", disk->disk_name);
1753 return;
1754 }
1755
1756 INIT_LIST_HEAD(&ev->node);
1757 ev->disk = disk;
1758 spin_lock_init(&ev->lock);
1759 mutex_init(&ev->block_mutex);
1760 ev->block = 1;
1761 ev->poll_msecs = -1;
1762 INIT_DELAYED_WORK(&ev->dwork, disk_events_workfn);
1763
1764 disk->ev = ev;
1765}
1766
1767static void disk_add_events(struct gendisk *disk)
1768{
1769 if (!disk->ev)
1770 return;
1771
1772 /* FIXME: error handling */
1773 if (sysfs_create_files(&disk_to_dev(disk)->kobj, disk_events_attrs) < 0)
1774 pr_warn("%s: failed to create sysfs files for events\n",
1775 disk->disk_name);
1776
1777 mutex_lock(&disk_events_mutex);
1778 list_add_tail(&disk->ev->node, &disk_events);
1779 mutex_unlock(&disk_events_mutex);
1780
1781 /*
1782 * Block count is initialized to 1 and the following initial
1783 * unblock kicks it into action.
1784 */
1785 __disk_unblock_events(disk, true);
1786}
1787
1788static void disk_del_events(struct gendisk *disk)
1789{
1790 if (!disk->ev)
1791 return;
1792
1793 disk_block_events(disk);
1794
1795 mutex_lock(&disk_events_mutex);
1796 list_del_init(&disk->ev->node);
1797 mutex_unlock(&disk_events_mutex);
1798
1799 sysfs_remove_files(&disk_to_dev(disk)->kobj, disk_events_attrs);
1800}
1801
1802static void disk_release_events(struct gendisk *disk)
1803{
1804 /* the block count should be 1 from disk_del_events() */
1805 WARN_ON_ONCE(disk->ev && disk->ev->block != 1);
1806 kfree(disk->ev);
1807}