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1 // SPDX-License-Identifier: GPL-2.0
2 /*
3  *  gendisk handling
4  */
5 
6 #include <linux/module.h>
7 #include <linux/fs.h>
8 #include <linux/genhd.h>
9 #include <linux/kdev_t.h>
10 #include <linux/kernel.h>
11 #include <linux/blkdev.h>
12 #include <linux/backing-dev.h>
13 #include <linux/init.h>
14 #include <linux/spinlock.h>
15 #include <linux/proc_fs.h>
16 #include <linux/seq_file.h>
17 #include <linux/slab.h>
18 #include <linux/kmod.h>
19 #include <linux/kobj_map.h>
20 #include <linux/mutex.h>
21 #include <linux/idr.h>
22 #include <linux/log2.h>
23 #include <linux/pm_runtime.h>
24 #include <linux/badblocks.h>
25 
26 #include "blk.h"
27 
28 static DEFINE_MUTEX(block_class_lock);
29 struct kobject *block_depr;
30 
31 /* for extended dynamic devt allocation, currently only one major is used */
32 #define NR_EXT_DEVT		(1 << MINORBITS)
33 
34 /* For extended devt allocation.  ext_devt_lock prevents look up
35  * results from going away underneath its user.
36  */
37 static DEFINE_SPINLOCK(ext_devt_lock);
38 static DEFINE_IDR(ext_devt_idr);
39 
40 static const struct device_type disk_type;
41 
42 static void disk_check_events(struct disk_events *ev,
43 			      unsigned int *clearing_ptr);
44 static void disk_alloc_events(struct gendisk *disk);
45 static void disk_add_events(struct gendisk *disk);
46 static void disk_del_events(struct gendisk *disk);
47 static void disk_release_events(struct gendisk *disk);
48 
part_inc_in_flight(struct request_queue * q,struct hd_struct * part,int rw)49 void part_inc_in_flight(struct request_queue *q, struct hd_struct *part, int rw)
50 {
51 	if (queue_is_mq(q))
52 		return;
53 
54 	part_stat_local_inc(part, in_flight[rw]);
55 	if (part->partno)
56 		part_stat_local_inc(&part_to_disk(part)->part0, in_flight[rw]);
57 }
58 
part_dec_in_flight(struct request_queue * q,struct hd_struct * part,int rw)59 void part_dec_in_flight(struct request_queue *q, struct hd_struct *part, int rw)
60 {
61 	if (queue_is_mq(q))
62 		return;
63 
64 	part_stat_local_dec(part, in_flight[rw]);
65 	if (part->partno)
66 		part_stat_local_dec(&part_to_disk(part)->part0, in_flight[rw]);
67 }
68 
part_in_flight(struct request_queue * q,struct hd_struct * part)69 unsigned int part_in_flight(struct request_queue *q, struct hd_struct *part)
70 {
71 	int cpu;
72 	unsigned int inflight;
73 
74 	if (queue_is_mq(q)) {
75 		return blk_mq_in_flight(q, part);
76 	}
77 
78 	inflight = 0;
79 	for_each_possible_cpu(cpu) {
80 		inflight += part_stat_local_read_cpu(part, in_flight[0], cpu) +
81 			    part_stat_local_read_cpu(part, in_flight[1], cpu);
82 	}
83 	if ((int)inflight < 0)
84 		inflight = 0;
85 
86 	return inflight;
87 }
88 
part_in_flight_rw(struct request_queue * q,struct hd_struct * part,unsigned int inflight[2])89 void part_in_flight_rw(struct request_queue *q, struct hd_struct *part,
90 		       unsigned int inflight[2])
91 {
92 	int cpu;
93 
94 	if (queue_is_mq(q)) {
95 		blk_mq_in_flight_rw(q, part, inflight);
96 		return;
97 	}
98 
99 	inflight[0] = 0;
100 	inflight[1] = 0;
101 	for_each_possible_cpu(cpu) {
102 		inflight[0] += part_stat_local_read_cpu(part, in_flight[0], cpu);
103 		inflight[1] += part_stat_local_read_cpu(part, in_flight[1], cpu);
104 	}
105 	if ((int)inflight[0] < 0)
106 		inflight[0] = 0;
107 	if ((int)inflight[1] < 0)
108 		inflight[1] = 0;
109 }
110 
__disk_get_part(struct gendisk * disk,int partno)111 struct hd_struct *__disk_get_part(struct gendisk *disk, int partno)
112 {
113 	struct disk_part_tbl *ptbl = rcu_dereference(disk->part_tbl);
114 
115 	if (unlikely(partno < 0 || partno >= ptbl->len))
116 		return NULL;
117 	return rcu_dereference(ptbl->part[partno]);
118 }
119 
120 /**
121  * disk_get_part - get partition
122  * @disk: disk to look partition from
123  * @partno: partition number
124  *
125  * Look for partition @partno from @disk.  If found, increment
126  * reference count and return it.
127  *
128  * CONTEXT:
129  * Don't care.
130  *
131  * RETURNS:
132  * Pointer to the found partition on success, NULL if not found.
133  */
disk_get_part(struct gendisk * disk,int partno)134 struct hd_struct *disk_get_part(struct gendisk *disk, int partno)
135 {
136 	struct hd_struct *part;
137 
138 	rcu_read_lock();
139 	part = __disk_get_part(disk, partno);
140 	if (part)
141 		get_device(part_to_dev(part));
142 	rcu_read_unlock();
143 
144 	return part;
145 }
146 EXPORT_SYMBOL_GPL(disk_get_part);
147 
148 /**
149  * disk_part_iter_init - initialize partition iterator
150  * @piter: iterator to initialize
151  * @disk: disk to iterate over
152  * @flags: DISK_PITER_* flags
153  *
154  * Initialize @piter so that it iterates over partitions of @disk.
155  *
156  * CONTEXT:
157  * Don't care.
158  */
disk_part_iter_init(struct disk_part_iter * piter,struct gendisk * disk,unsigned int flags)159 void disk_part_iter_init(struct disk_part_iter *piter, struct gendisk *disk,
160 			  unsigned int flags)
161 {
162 	struct disk_part_tbl *ptbl;
163 
164 	rcu_read_lock();
165 	ptbl = rcu_dereference(disk->part_tbl);
166 
167 	piter->disk = disk;
168 	piter->part = NULL;
169 
170 	if (flags & DISK_PITER_REVERSE)
171 		piter->idx = ptbl->len - 1;
172 	else if (flags & (DISK_PITER_INCL_PART0 | DISK_PITER_INCL_EMPTY_PART0))
173 		piter->idx = 0;
174 	else
175 		piter->idx = 1;
176 
177 	piter->flags = flags;
178 
179 	rcu_read_unlock();
180 }
181 EXPORT_SYMBOL_GPL(disk_part_iter_init);
182 
183 /**
184  * disk_part_iter_next - proceed iterator to the next partition and return it
185  * @piter: iterator of interest
186  *
187  * Proceed @piter to the next partition and return it.
188  *
189  * CONTEXT:
190  * Don't care.
191  */
disk_part_iter_next(struct disk_part_iter * piter)192 struct hd_struct *disk_part_iter_next(struct disk_part_iter *piter)
193 {
194 	struct disk_part_tbl *ptbl;
195 	int inc, end;
196 
197 	/* put the last partition */
198 	disk_put_part(piter->part);
199 	piter->part = NULL;
200 
201 	/* get part_tbl */
202 	rcu_read_lock();
203 	ptbl = rcu_dereference(piter->disk->part_tbl);
204 
205 	/* determine iteration parameters */
206 	if (piter->flags & DISK_PITER_REVERSE) {
207 		inc = -1;
208 		if (piter->flags & (DISK_PITER_INCL_PART0 |
209 				    DISK_PITER_INCL_EMPTY_PART0))
210 			end = -1;
211 		else
212 			end = 0;
213 	} else {
214 		inc = 1;
215 		end = ptbl->len;
216 	}
217 
218 	/* iterate to the next partition */
219 	for (; piter->idx != end; piter->idx += inc) {
220 		struct hd_struct *part;
221 
222 		part = rcu_dereference(ptbl->part[piter->idx]);
223 		if (!part)
224 			continue;
225 		if (!part_nr_sects_read(part) &&
226 		    !(piter->flags & DISK_PITER_INCL_EMPTY) &&
227 		    !(piter->flags & DISK_PITER_INCL_EMPTY_PART0 &&
228 		      piter->idx == 0))
229 			continue;
230 
231 		get_device(part_to_dev(part));
232 		piter->part = part;
233 		piter->idx += inc;
234 		break;
235 	}
236 
237 	rcu_read_unlock();
238 
239 	return piter->part;
240 }
241 EXPORT_SYMBOL_GPL(disk_part_iter_next);
242 
243 /**
244  * disk_part_iter_exit - finish up partition iteration
245  * @piter: iter of interest
246  *
247  * Called when iteration is over.  Cleans up @piter.
248  *
249  * CONTEXT:
250  * Don't care.
251  */
disk_part_iter_exit(struct disk_part_iter * piter)252 void disk_part_iter_exit(struct disk_part_iter *piter)
253 {
254 	disk_put_part(piter->part);
255 	piter->part = NULL;
256 }
257 EXPORT_SYMBOL_GPL(disk_part_iter_exit);
258 
sector_in_part(struct hd_struct * part,sector_t sector)259 static inline int sector_in_part(struct hd_struct *part, sector_t sector)
260 {
261 	return part->start_sect <= sector &&
262 		sector < part->start_sect + part_nr_sects_read(part);
263 }
264 
265 /**
266  * disk_map_sector_rcu - map sector to partition
267  * @disk: gendisk of interest
268  * @sector: sector to map
269  *
270  * Find out which partition @sector maps to on @disk.  This is
271  * primarily used for stats accounting.
272  *
273  * CONTEXT:
274  * RCU read locked.  The returned partition pointer is valid only
275  * while preemption is disabled.
276  *
277  * RETURNS:
278  * Found partition on success, part0 is returned if no partition matches
279  */
disk_map_sector_rcu(struct gendisk * disk,sector_t sector)280 struct hd_struct *disk_map_sector_rcu(struct gendisk *disk, sector_t sector)
281 {
282 	struct disk_part_tbl *ptbl;
283 	struct hd_struct *part;
284 	int i;
285 
286 	ptbl = rcu_dereference(disk->part_tbl);
287 
288 	part = rcu_dereference(ptbl->last_lookup);
289 	if (part && sector_in_part(part, sector))
290 		return part;
291 
292 	for (i = 1; i < ptbl->len; i++) {
293 		part = rcu_dereference(ptbl->part[i]);
294 
295 		if (part && sector_in_part(part, sector)) {
296 			rcu_assign_pointer(ptbl->last_lookup, part);
297 			return part;
298 		}
299 	}
300 	return &disk->part0;
301 }
302 EXPORT_SYMBOL_GPL(disk_map_sector_rcu);
303 
304 /*
305  * Can be deleted altogether. Later.
306  *
307  */
308 #define BLKDEV_MAJOR_HASH_SIZE 255
309 static struct blk_major_name {
310 	struct blk_major_name *next;
311 	int major;
312 	char name[16];
313 } *major_names[BLKDEV_MAJOR_HASH_SIZE];
314 
315 /* index in the above - for now: assume no multimajor ranges */
major_to_index(unsigned major)316 static inline int major_to_index(unsigned major)
317 {
318 	return major % BLKDEV_MAJOR_HASH_SIZE;
319 }
320 
321 #ifdef CONFIG_PROC_FS
blkdev_show(struct seq_file * seqf,off_t offset)322 void blkdev_show(struct seq_file *seqf, off_t offset)
323 {
324 	struct blk_major_name *dp;
325 
326 	mutex_lock(&block_class_lock);
327 	for (dp = major_names[major_to_index(offset)]; dp; dp = dp->next)
328 		if (dp->major == offset)
329 			seq_printf(seqf, "%3d %s\n", dp->major, dp->name);
330 	mutex_unlock(&block_class_lock);
331 }
332 #endif /* CONFIG_PROC_FS */
333 
334 /**
335  * register_blkdev - register a new block device
336  *
337  * @major: the requested major device number [1..BLKDEV_MAJOR_MAX-1]. If
338  *         @major = 0, try to allocate any unused major number.
339  * @name: the name of the new block device as a zero terminated string
340  *
341  * The @name must be unique within the system.
342  *
343  * The return value depends on the @major input parameter:
344  *
345  *  - if a major device number was requested in range [1..BLKDEV_MAJOR_MAX-1]
346  *    then the function returns zero on success, or a negative error code
347  *  - if any unused major number was requested with @major = 0 parameter
348  *    then the return value is the allocated major number in range
349  *    [1..BLKDEV_MAJOR_MAX-1] or a negative error code otherwise
350  *
351  * See Documentation/admin-guide/devices.txt for the list of allocated
352  * major numbers.
353  */
register_blkdev(unsigned int major,const char * name)354 int register_blkdev(unsigned int major, const char *name)
355 {
356 	struct blk_major_name **n, *p;
357 	int index, ret = 0;
358 
359 	mutex_lock(&block_class_lock);
360 
361 	/* temporary */
362 	if (major == 0) {
363 		for (index = ARRAY_SIZE(major_names)-1; index > 0; index--) {
364 			if (major_names[index] == NULL)
365 				break;
366 		}
367 
368 		if (index == 0) {
369 			printk("%s: failed to get major for %s\n",
370 			       __func__, name);
371 			ret = -EBUSY;
372 			goto out;
373 		}
374 		major = index;
375 		ret = major;
376 	}
377 
378 	if (major >= BLKDEV_MAJOR_MAX) {
379 		pr_err("%s: major requested (%u) is greater than the maximum (%u) for %s\n",
380 		       __func__, major, BLKDEV_MAJOR_MAX-1, name);
381 
382 		ret = -EINVAL;
383 		goto out;
384 	}
385 
386 	p = kmalloc(sizeof(struct blk_major_name), GFP_KERNEL);
387 	if (p == NULL) {
388 		ret = -ENOMEM;
389 		goto out;
390 	}
391 
392 	p->major = major;
393 	strlcpy(p->name, name, sizeof(p->name));
394 	p->next = NULL;
395 	index = major_to_index(major);
396 
397 	for (n = &major_names[index]; *n; n = &(*n)->next) {
398 		if ((*n)->major == major)
399 			break;
400 	}
401 	if (!*n)
402 		*n = p;
403 	else
404 		ret = -EBUSY;
405 
406 	if (ret < 0) {
407 		printk("register_blkdev: cannot get major %u for %s\n",
408 		       major, name);
409 		kfree(p);
410 	}
411 out:
412 	mutex_unlock(&block_class_lock);
413 	return ret;
414 }
415 
416 EXPORT_SYMBOL(register_blkdev);
417 
unregister_blkdev(unsigned int major,const char * name)418 void unregister_blkdev(unsigned int major, const char *name)
419 {
420 	struct blk_major_name **n;
421 	struct blk_major_name *p = NULL;
422 	int index = major_to_index(major);
423 
424 	mutex_lock(&block_class_lock);
425 	for (n = &major_names[index]; *n; n = &(*n)->next)
426 		if ((*n)->major == major)
427 			break;
428 	if (!*n || strcmp((*n)->name, name)) {
429 		WARN_ON(1);
430 	} else {
431 		p = *n;
432 		*n = p->next;
433 	}
434 	mutex_unlock(&block_class_lock);
435 	kfree(p);
436 }
437 
438 EXPORT_SYMBOL(unregister_blkdev);
439 
440 static struct kobj_map *bdev_map;
441 
442 /**
443  * blk_mangle_minor - scatter minor numbers apart
444  * @minor: minor number to mangle
445  *
446  * Scatter consecutively allocated @minor number apart if MANGLE_DEVT
447  * is enabled.  Mangling twice gives the original value.
448  *
449  * RETURNS:
450  * Mangled value.
451  *
452  * CONTEXT:
453  * Don't care.
454  */
blk_mangle_minor(int minor)455 static int blk_mangle_minor(int minor)
456 {
457 #ifdef CONFIG_DEBUG_BLOCK_EXT_DEVT
458 	int i;
459 
460 	for (i = 0; i < MINORBITS / 2; i++) {
461 		int low = minor & (1 << i);
462 		int high = minor & (1 << (MINORBITS - 1 - i));
463 		int distance = MINORBITS - 1 - 2 * i;
464 
465 		minor ^= low | high;	/* clear both bits */
466 		low <<= distance;	/* swap the positions */
467 		high >>= distance;
468 		minor |= low | high;	/* and set */
469 	}
470 #endif
471 	return minor;
472 }
473 
474 /**
475  * blk_alloc_devt - allocate a dev_t for a partition
476  * @part: partition to allocate dev_t for
477  * @devt: out parameter for resulting dev_t
478  *
479  * Allocate a dev_t for block device.
480  *
481  * RETURNS:
482  * 0 on success, allocated dev_t is returned in *@devt.  -errno on
483  * failure.
484  *
485  * CONTEXT:
486  * Might sleep.
487  */
blk_alloc_devt(struct hd_struct * part,dev_t * devt)488 int blk_alloc_devt(struct hd_struct *part, dev_t *devt)
489 {
490 	struct gendisk *disk = part_to_disk(part);
491 	int idx;
492 
493 	/* in consecutive minor range? */
494 	if (part->partno < disk->minors) {
495 		*devt = MKDEV(disk->major, disk->first_minor + part->partno);
496 		return 0;
497 	}
498 
499 	/* allocate ext devt */
500 	idr_preload(GFP_KERNEL);
501 
502 	spin_lock_bh(&ext_devt_lock);
503 	idx = idr_alloc(&ext_devt_idr, part, 0, NR_EXT_DEVT, GFP_NOWAIT);
504 	spin_unlock_bh(&ext_devt_lock);
505 
506 	idr_preload_end();
507 	if (idx < 0)
508 		return idx == -ENOSPC ? -EBUSY : idx;
509 
510 	*devt = MKDEV(BLOCK_EXT_MAJOR, blk_mangle_minor(idx));
511 	return 0;
512 }
513 
514 /**
515  * blk_free_devt - free a dev_t
516  * @devt: dev_t to free
517  *
518  * Free @devt which was allocated using blk_alloc_devt().
519  *
520  * CONTEXT:
521  * Might sleep.
522  */
blk_free_devt(dev_t devt)523 void blk_free_devt(dev_t devt)
524 {
525 	if (devt == MKDEV(0, 0))
526 		return;
527 
528 	if (MAJOR(devt) == BLOCK_EXT_MAJOR) {
529 		spin_lock_bh(&ext_devt_lock);
530 		idr_remove(&ext_devt_idr, blk_mangle_minor(MINOR(devt)));
531 		spin_unlock_bh(&ext_devt_lock);
532 	}
533 }
534 
535 /*
536  * We invalidate devt by assigning NULL pointer for devt in idr.
537  */
blk_invalidate_devt(dev_t devt)538 void blk_invalidate_devt(dev_t devt)
539 {
540 	if (MAJOR(devt) == BLOCK_EXT_MAJOR) {
541 		spin_lock_bh(&ext_devt_lock);
542 		idr_replace(&ext_devt_idr, NULL, blk_mangle_minor(MINOR(devt)));
543 		spin_unlock_bh(&ext_devt_lock);
544 	}
545 }
546 
bdevt_str(dev_t devt,char * buf)547 static char *bdevt_str(dev_t devt, char *buf)
548 {
549 	if (MAJOR(devt) <= 0xff && MINOR(devt) <= 0xff) {
550 		char tbuf[BDEVT_SIZE];
551 		snprintf(tbuf, BDEVT_SIZE, "%02x%02x", MAJOR(devt), MINOR(devt));
552 		snprintf(buf, BDEVT_SIZE, "%-9s", tbuf);
553 	} else
554 		snprintf(buf, BDEVT_SIZE, "%03x:%05x", MAJOR(devt), MINOR(devt));
555 
556 	return buf;
557 }
558 
559 /*
560  * Register device numbers dev..(dev+range-1)
561  * range must be nonzero
562  * The hash chain is sorted on range, so that subranges can override.
563  */
blk_register_region(dev_t devt,unsigned long range,struct module * module,struct kobject * (* probe)(dev_t,int *,void *),int (* lock)(dev_t,void *),void * data)564 void blk_register_region(dev_t devt, unsigned long range, struct module *module,
565 			 struct kobject *(*probe)(dev_t, int *, void *),
566 			 int (*lock)(dev_t, void *), void *data)
567 {
568 	kobj_map(bdev_map, devt, range, module, probe, lock, data);
569 }
570 
571 EXPORT_SYMBOL(blk_register_region);
572 
blk_unregister_region(dev_t devt,unsigned long range)573 void blk_unregister_region(dev_t devt, unsigned long range)
574 {
575 	kobj_unmap(bdev_map, devt, range);
576 }
577 
578 EXPORT_SYMBOL(blk_unregister_region);
579 
exact_match(dev_t devt,int * partno,void * data)580 static struct kobject *exact_match(dev_t devt, int *partno, void *data)
581 {
582 	struct gendisk *p = data;
583 
584 	return &disk_to_dev(p)->kobj;
585 }
586 
exact_lock(dev_t devt,void * data)587 static int exact_lock(dev_t devt, void *data)
588 {
589 	struct gendisk *p = data;
590 
591 	if (!get_disk_and_module(p))
592 		return -1;
593 	return 0;
594 }
595 
register_disk(struct device * parent,struct gendisk * disk,const struct attribute_group ** groups)596 static void register_disk(struct device *parent, struct gendisk *disk,
597 			  const struct attribute_group **groups)
598 {
599 	struct device *ddev = disk_to_dev(disk);
600 	struct block_device *bdev;
601 	struct disk_part_iter piter;
602 	struct hd_struct *part;
603 	int err;
604 
605 	ddev->parent = parent;
606 
607 	dev_set_name(ddev, "%s", disk->disk_name);
608 
609 	/* delay uevents, until we scanned partition table */
610 	dev_set_uevent_suppress(ddev, 1);
611 
612 	if (groups) {
613 		WARN_ON(ddev->groups);
614 		ddev->groups = groups;
615 	}
616 	if (device_add(ddev))
617 		return;
618 	if (!sysfs_deprecated) {
619 		err = sysfs_create_link(block_depr, &ddev->kobj,
620 					kobject_name(&ddev->kobj));
621 		if (err) {
622 			device_del(ddev);
623 			return;
624 		}
625 	}
626 
627 	/*
628 	 * avoid probable deadlock caused by allocating memory with
629 	 * GFP_KERNEL in runtime_resume callback of its all ancestor
630 	 * devices
631 	 */
632 	pm_runtime_set_memalloc_noio(ddev, true);
633 
634 	disk->part0.holder_dir = kobject_create_and_add("holders", &ddev->kobj);
635 	disk->slave_dir = kobject_create_and_add("slaves", &ddev->kobj);
636 
637 	if (disk->flags & GENHD_FL_HIDDEN) {
638 		dev_set_uevent_suppress(ddev, 0);
639 		return;
640 	}
641 
642 	/* No minors to use for partitions */
643 	if (!disk_part_scan_enabled(disk))
644 		goto exit;
645 
646 	/* No such device (e.g., media were just removed) */
647 	if (!get_capacity(disk))
648 		goto exit;
649 
650 	bdev = bdget_disk(disk, 0);
651 	if (!bdev)
652 		goto exit;
653 
654 	bdev->bd_invalidated = 1;
655 	err = blkdev_get(bdev, FMODE_READ, NULL);
656 	if (err < 0)
657 		goto exit;
658 	blkdev_put(bdev, FMODE_READ);
659 
660 exit:
661 	/* announce disk after possible partitions are created */
662 	dev_set_uevent_suppress(ddev, 0);
663 	kobject_uevent(&ddev->kobj, KOBJ_ADD);
664 
665 	/* announce possible partitions */
666 	disk_part_iter_init(&piter, disk, 0);
667 	while ((part = disk_part_iter_next(&piter)))
668 		kobject_uevent(&part_to_dev(part)->kobj, KOBJ_ADD);
669 	disk_part_iter_exit(&piter);
670 
671 	if (disk->queue->backing_dev_info->dev) {
672 		err = sysfs_create_link(&ddev->kobj,
673 			  &disk->queue->backing_dev_info->dev->kobj,
674 			  "bdi");
675 		WARN_ON(err);
676 	}
677 }
678 
679 /**
680  * __device_add_disk - add disk information to kernel list
681  * @parent: parent device for the disk
682  * @disk: per-device partitioning information
683  * @groups: Additional per-device sysfs groups
684  * @register_queue: register the queue if set to true
685  *
686  * This function registers the partitioning information in @disk
687  * with the kernel.
688  *
689  * FIXME: error handling
690  */
__device_add_disk(struct device * parent,struct gendisk * disk,const struct attribute_group ** groups,bool register_queue)691 static void __device_add_disk(struct device *parent, struct gendisk *disk,
692 			      const struct attribute_group **groups,
693 			      bool register_queue)
694 {
695 	dev_t devt;
696 	int retval;
697 
698 	/*
699 	 * The disk queue should now be all set with enough information about
700 	 * the device for the elevator code to pick an adequate default
701 	 * elevator if one is needed, that is, for devices requesting queue
702 	 * registration.
703 	 */
704 	if (register_queue)
705 		elevator_init_mq(disk->queue);
706 
707 	/* minors == 0 indicates to use ext devt from part0 and should
708 	 * be accompanied with EXT_DEVT flag.  Make sure all
709 	 * parameters make sense.
710 	 */
711 	WARN_ON(disk->minors && !(disk->major || disk->first_minor));
712 	WARN_ON(!disk->minors &&
713 		!(disk->flags & (GENHD_FL_EXT_DEVT | GENHD_FL_HIDDEN)));
714 
715 	disk->flags |= GENHD_FL_UP;
716 
717 	retval = blk_alloc_devt(&disk->part0, &devt);
718 	if (retval) {
719 		WARN_ON(1);
720 		return;
721 	}
722 	disk->major = MAJOR(devt);
723 	disk->first_minor = MINOR(devt);
724 
725 	disk_alloc_events(disk);
726 
727 	if (disk->flags & GENHD_FL_HIDDEN) {
728 		/*
729 		 * Don't let hidden disks show up in /proc/partitions,
730 		 * and don't bother scanning for partitions either.
731 		 */
732 		disk->flags |= GENHD_FL_SUPPRESS_PARTITION_INFO;
733 		disk->flags |= GENHD_FL_NO_PART_SCAN;
734 	} else {
735 		int ret;
736 
737 		/* Register BDI before referencing it from bdev */
738 		disk_to_dev(disk)->devt = devt;
739 		ret = bdi_register_owner(disk->queue->backing_dev_info,
740 						disk_to_dev(disk));
741 		WARN_ON(ret);
742 		blk_register_region(disk_devt(disk), disk->minors, NULL,
743 				    exact_match, exact_lock, disk);
744 	}
745 	register_disk(parent, disk, groups);
746 	if (register_queue)
747 		blk_register_queue(disk);
748 
749 	/*
750 	 * Take an extra ref on queue which will be put on disk_release()
751 	 * so that it sticks around as long as @disk is there.
752 	 */
753 	WARN_ON_ONCE(!blk_get_queue(disk->queue));
754 
755 	disk_add_events(disk);
756 	blk_integrity_add(disk);
757 }
758 
device_add_disk(struct device * parent,struct gendisk * disk,const struct attribute_group ** groups)759 void device_add_disk(struct device *parent, struct gendisk *disk,
760 		     const struct attribute_group **groups)
761 
762 {
763 	__device_add_disk(parent, disk, groups, true);
764 }
765 EXPORT_SYMBOL(device_add_disk);
766 
device_add_disk_no_queue_reg(struct device * parent,struct gendisk * disk)767 void device_add_disk_no_queue_reg(struct device *parent, struct gendisk *disk)
768 {
769 	__device_add_disk(parent, disk, NULL, false);
770 }
771 EXPORT_SYMBOL(device_add_disk_no_queue_reg);
772 
del_gendisk(struct gendisk * disk)773 void del_gendisk(struct gendisk *disk)
774 {
775 	struct disk_part_iter piter;
776 	struct hd_struct *part;
777 
778 	blk_integrity_del(disk);
779 	disk_del_events(disk);
780 
781 	/*
782 	 * Block lookups of the disk until all bdevs are unhashed and the
783 	 * disk is marked as dead (GENHD_FL_UP cleared).
784 	 */
785 	down_write(&disk->lookup_sem);
786 	/* invalidate stuff */
787 	disk_part_iter_init(&piter, disk,
788 			     DISK_PITER_INCL_EMPTY | DISK_PITER_REVERSE);
789 	while ((part = disk_part_iter_next(&piter))) {
790 		invalidate_partition(disk, part->partno);
791 		bdev_unhash_inode(part_devt(part));
792 		delete_partition(disk, part->partno);
793 	}
794 	disk_part_iter_exit(&piter);
795 
796 	invalidate_partition(disk, 0);
797 	bdev_unhash_inode(disk_devt(disk));
798 	set_capacity(disk, 0);
799 	disk->flags &= ~GENHD_FL_UP;
800 	up_write(&disk->lookup_sem);
801 
802 	if (!(disk->flags & GENHD_FL_HIDDEN))
803 		sysfs_remove_link(&disk_to_dev(disk)->kobj, "bdi");
804 	if (disk->queue) {
805 		/*
806 		 * Unregister bdi before releasing device numbers (as they can
807 		 * get reused and we'd get clashes in sysfs).
808 		 */
809 		if (!(disk->flags & GENHD_FL_HIDDEN))
810 			bdi_unregister(disk->queue->backing_dev_info);
811 		blk_unregister_queue(disk);
812 	} else {
813 		WARN_ON(1);
814 	}
815 
816 	if (!(disk->flags & GENHD_FL_HIDDEN))
817 		blk_unregister_region(disk_devt(disk), disk->minors);
818 	/*
819 	 * Remove gendisk pointer from idr so that it cannot be looked up
820 	 * while RCU period before freeing gendisk is running to prevent
821 	 * use-after-free issues. Note that the device number stays
822 	 * "in-use" until we really free the gendisk.
823 	 */
824 	blk_invalidate_devt(disk_devt(disk));
825 
826 	kobject_put(disk->part0.holder_dir);
827 	kobject_put(disk->slave_dir);
828 
829 	part_stat_set_all(&disk->part0, 0);
830 	disk->part0.stamp = 0;
831 	if (!sysfs_deprecated)
832 		sysfs_remove_link(block_depr, dev_name(disk_to_dev(disk)));
833 	pm_runtime_set_memalloc_noio(disk_to_dev(disk), false);
834 	device_del(disk_to_dev(disk));
835 }
836 EXPORT_SYMBOL(del_gendisk);
837 
838 /* sysfs access to bad-blocks list. */
disk_badblocks_show(struct device * dev,struct device_attribute * attr,char * page)839 static ssize_t disk_badblocks_show(struct device *dev,
840 					struct device_attribute *attr,
841 					char *page)
842 {
843 	struct gendisk *disk = dev_to_disk(dev);
844 
845 	if (!disk->bb)
846 		return sprintf(page, "\n");
847 
848 	return badblocks_show(disk->bb, page, 0);
849 }
850 
disk_badblocks_store(struct device * dev,struct device_attribute * attr,const char * page,size_t len)851 static ssize_t disk_badblocks_store(struct device *dev,
852 					struct device_attribute *attr,
853 					const char *page, size_t len)
854 {
855 	struct gendisk *disk = dev_to_disk(dev);
856 
857 	if (!disk->bb)
858 		return -ENXIO;
859 
860 	return badblocks_store(disk->bb, page, len, 0);
861 }
862 
863 /**
864  * get_gendisk - get partitioning information for a given device
865  * @devt: device to get partitioning information for
866  * @partno: returned partition index
867  *
868  * This function gets the structure containing partitioning
869  * information for the given device @devt.
870  */
get_gendisk(dev_t devt,int * partno)871 struct gendisk *get_gendisk(dev_t devt, int *partno)
872 {
873 	struct gendisk *disk = NULL;
874 
875 	if (MAJOR(devt) != BLOCK_EXT_MAJOR) {
876 		struct kobject *kobj;
877 
878 		kobj = kobj_lookup(bdev_map, devt, partno);
879 		if (kobj)
880 			disk = dev_to_disk(kobj_to_dev(kobj));
881 	} else {
882 		struct hd_struct *part;
883 
884 		spin_lock_bh(&ext_devt_lock);
885 		part = idr_find(&ext_devt_idr, blk_mangle_minor(MINOR(devt)));
886 		if (part && get_disk_and_module(part_to_disk(part))) {
887 			*partno = part->partno;
888 			disk = part_to_disk(part);
889 		}
890 		spin_unlock_bh(&ext_devt_lock);
891 	}
892 
893 	if (!disk)
894 		return NULL;
895 
896 	/*
897 	 * Synchronize with del_gendisk() to not return disk that is being
898 	 * destroyed.
899 	 */
900 	down_read(&disk->lookup_sem);
901 	if (unlikely((disk->flags & GENHD_FL_HIDDEN) ||
902 		     !(disk->flags & GENHD_FL_UP))) {
903 		up_read(&disk->lookup_sem);
904 		put_disk_and_module(disk);
905 		disk = NULL;
906 	} else {
907 		up_read(&disk->lookup_sem);
908 	}
909 	return disk;
910 }
911 EXPORT_SYMBOL(get_gendisk);
912 
913 /**
914  * bdget_disk - do bdget() by gendisk and partition number
915  * @disk: gendisk of interest
916  * @partno: partition number
917  *
918  * Find partition @partno from @disk, do bdget() on it.
919  *
920  * CONTEXT:
921  * Don't care.
922  *
923  * RETURNS:
924  * Resulting block_device on success, NULL on failure.
925  */
bdget_disk(struct gendisk * disk,int partno)926 struct block_device *bdget_disk(struct gendisk *disk, int partno)
927 {
928 	struct hd_struct *part;
929 	struct block_device *bdev = NULL;
930 
931 	part = disk_get_part(disk, partno);
932 	if (part)
933 		bdev = bdget(part_devt(part));
934 	disk_put_part(part);
935 
936 	return bdev;
937 }
938 EXPORT_SYMBOL(bdget_disk);
939 
940 /*
941  * print a full list of all partitions - intended for places where the root
942  * filesystem can't be mounted and thus to give the victim some idea of what
943  * went wrong
944  */
printk_all_partitions(void)945 void __init printk_all_partitions(void)
946 {
947 	struct class_dev_iter iter;
948 	struct device *dev;
949 
950 	class_dev_iter_init(&iter, &block_class, NULL, &disk_type);
951 	while ((dev = class_dev_iter_next(&iter))) {
952 		struct gendisk *disk = dev_to_disk(dev);
953 		struct disk_part_iter piter;
954 		struct hd_struct *part;
955 		char name_buf[BDEVNAME_SIZE];
956 		char devt_buf[BDEVT_SIZE];
957 
958 		/*
959 		 * Don't show empty devices or things that have been
960 		 * suppressed
961 		 */
962 		if (get_capacity(disk) == 0 ||
963 		    (disk->flags & GENHD_FL_SUPPRESS_PARTITION_INFO))
964 			continue;
965 
966 		/*
967 		 * Note, unlike /proc/partitions, I am showing the
968 		 * numbers in hex - the same format as the root=
969 		 * option takes.
970 		 */
971 		disk_part_iter_init(&piter, disk, DISK_PITER_INCL_PART0);
972 		while ((part = disk_part_iter_next(&piter))) {
973 			bool is_part0 = part == &disk->part0;
974 
975 			printk("%s%s %10llu %s %s", is_part0 ? "" : "  ",
976 			       bdevt_str(part_devt(part), devt_buf),
977 			       (unsigned long long)part_nr_sects_read(part) >> 1
978 			       , disk_name(disk, part->partno, name_buf),
979 			       part->info ? part->info->uuid : "");
980 			if (is_part0) {
981 				if (dev->parent && dev->parent->driver)
982 					printk(" driver: %s\n",
983 					      dev->parent->driver->name);
984 				else
985 					printk(" (driver?)\n");
986 			} else
987 				printk("\n");
988 		}
989 		disk_part_iter_exit(&piter);
990 	}
991 	class_dev_iter_exit(&iter);
992 }
993 
994 #ifdef CONFIG_PROC_FS
995 /* iterator */
disk_seqf_start(struct seq_file * seqf,loff_t * pos)996 static void *disk_seqf_start(struct seq_file *seqf, loff_t *pos)
997 {
998 	loff_t skip = *pos;
999 	struct class_dev_iter *iter;
1000 	struct device *dev;
1001 
1002 	iter = kmalloc(sizeof(*iter), GFP_KERNEL);
1003 	if (!iter)
1004 		return ERR_PTR(-ENOMEM);
1005 
1006 	seqf->private = iter;
1007 	class_dev_iter_init(iter, &block_class, NULL, &disk_type);
1008 	do {
1009 		dev = class_dev_iter_next(iter);
1010 		if (!dev)
1011 			return NULL;
1012 	} while (skip--);
1013 
1014 	return dev_to_disk(dev);
1015 }
1016 
disk_seqf_next(struct seq_file * seqf,void * v,loff_t * pos)1017 static void *disk_seqf_next(struct seq_file *seqf, void *v, loff_t *pos)
1018 {
1019 	struct device *dev;
1020 
1021 	(*pos)++;
1022 	dev = class_dev_iter_next(seqf->private);
1023 	if (dev)
1024 		return dev_to_disk(dev);
1025 
1026 	return NULL;
1027 }
1028 
disk_seqf_stop(struct seq_file * seqf,void * v)1029 static void disk_seqf_stop(struct seq_file *seqf, void *v)
1030 {
1031 	struct class_dev_iter *iter = seqf->private;
1032 
1033 	/* stop is called even after start failed :-( */
1034 	if (iter) {
1035 		class_dev_iter_exit(iter);
1036 		kfree(iter);
1037 		seqf->private = NULL;
1038 	}
1039 }
1040 
show_partition_start(struct seq_file * seqf,loff_t * pos)1041 static void *show_partition_start(struct seq_file *seqf, loff_t *pos)
1042 {
1043 	void *p;
1044 
1045 	p = disk_seqf_start(seqf, pos);
1046 	if (!IS_ERR_OR_NULL(p) && !*pos)
1047 		seq_puts(seqf, "major minor  #blocks  name\n\n");
1048 	return p;
1049 }
1050 
show_partition(struct seq_file * seqf,void * v)1051 static int show_partition(struct seq_file *seqf, void *v)
1052 {
1053 	struct gendisk *sgp = v;
1054 	struct disk_part_iter piter;
1055 	struct hd_struct *part;
1056 	char buf[BDEVNAME_SIZE];
1057 
1058 	/* Don't show non-partitionable removeable devices or empty devices */
1059 	if (!get_capacity(sgp) || (!disk_max_parts(sgp) &&
1060 				   (sgp->flags & GENHD_FL_REMOVABLE)))
1061 		return 0;
1062 	if (sgp->flags & GENHD_FL_SUPPRESS_PARTITION_INFO)
1063 		return 0;
1064 
1065 	/* show the full disk and all non-0 size partitions of it */
1066 	disk_part_iter_init(&piter, sgp, DISK_PITER_INCL_PART0);
1067 	while ((part = disk_part_iter_next(&piter)))
1068 		seq_printf(seqf, "%4d  %7d %10llu %s\n",
1069 			   MAJOR(part_devt(part)), MINOR(part_devt(part)),
1070 			   (unsigned long long)part_nr_sects_read(part) >> 1,
1071 			   disk_name(sgp, part->partno, buf));
1072 	disk_part_iter_exit(&piter);
1073 
1074 	return 0;
1075 }
1076 
1077 static const struct seq_operations partitions_op = {
1078 	.start	= show_partition_start,
1079 	.next	= disk_seqf_next,
1080 	.stop	= disk_seqf_stop,
1081 	.show	= show_partition
1082 };
1083 #endif
1084 
1085 
base_probe(dev_t devt,int * partno,void * data)1086 static struct kobject *base_probe(dev_t devt, int *partno, void *data)
1087 {
1088 	if (request_module("block-major-%d-%d", MAJOR(devt), MINOR(devt)) > 0)
1089 		/* Make old-style 2.4 aliases work */
1090 		request_module("block-major-%d", MAJOR(devt));
1091 	return NULL;
1092 }
1093 
genhd_device_init(void)1094 static int __init genhd_device_init(void)
1095 {
1096 	int error;
1097 
1098 	block_class.dev_kobj = sysfs_dev_block_kobj;
1099 	error = class_register(&block_class);
1100 	if (unlikely(error))
1101 		return error;
1102 	bdev_map = kobj_map_init(base_probe, &block_class_lock);
1103 	blk_dev_init();
1104 
1105 	register_blkdev(BLOCK_EXT_MAJOR, "blkext");
1106 
1107 	/* create top-level block dir */
1108 	if (!sysfs_deprecated)
1109 		block_depr = kobject_create_and_add("block", NULL);
1110 	return 0;
1111 }
1112 
1113 subsys_initcall(genhd_device_init);
1114 
disk_range_show(struct device * dev,struct device_attribute * attr,char * buf)1115 static ssize_t disk_range_show(struct device *dev,
1116 			       struct device_attribute *attr, char *buf)
1117 {
1118 	struct gendisk *disk = dev_to_disk(dev);
1119 
1120 	return sprintf(buf, "%d\n", disk->minors);
1121 }
1122 
disk_ext_range_show(struct device * dev,struct device_attribute * attr,char * buf)1123 static ssize_t disk_ext_range_show(struct device *dev,
1124 				   struct device_attribute *attr, char *buf)
1125 {
1126 	struct gendisk *disk = dev_to_disk(dev);
1127 
1128 	return sprintf(buf, "%d\n", disk_max_parts(disk));
1129 }
1130 
disk_removable_show(struct device * dev,struct device_attribute * attr,char * buf)1131 static ssize_t disk_removable_show(struct device *dev,
1132 				   struct device_attribute *attr, char *buf)
1133 {
1134 	struct gendisk *disk = dev_to_disk(dev);
1135 
1136 	return sprintf(buf, "%d\n",
1137 		       (disk->flags & GENHD_FL_REMOVABLE ? 1 : 0));
1138 }
1139 
disk_hidden_show(struct device * dev,struct device_attribute * attr,char * buf)1140 static ssize_t disk_hidden_show(struct device *dev,
1141 				   struct device_attribute *attr, char *buf)
1142 {
1143 	struct gendisk *disk = dev_to_disk(dev);
1144 
1145 	return sprintf(buf, "%d\n",
1146 		       (disk->flags & GENHD_FL_HIDDEN ? 1 : 0));
1147 }
1148 
disk_ro_show(struct device * dev,struct device_attribute * attr,char * buf)1149 static ssize_t disk_ro_show(struct device *dev,
1150 				   struct device_attribute *attr, char *buf)
1151 {
1152 	struct gendisk *disk = dev_to_disk(dev);
1153 
1154 	return sprintf(buf, "%d\n", get_disk_ro(disk) ? 1 : 0);
1155 }
1156 
disk_capability_show(struct device * dev,struct device_attribute * attr,char * buf)1157 static ssize_t disk_capability_show(struct device *dev,
1158 				    struct device_attribute *attr, char *buf)
1159 {
1160 	struct gendisk *disk = dev_to_disk(dev);
1161 
1162 	return sprintf(buf, "%x\n", disk->flags);
1163 }
1164 
disk_alignment_offset_show(struct device * dev,struct device_attribute * attr,char * buf)1165 static ssize_t disk_alignment_offset_show(struct device *dev,
1166 					  struct device_attribute *attr,
1167 					  char *buf)
1168 {
1169 	struct gendisk *disk = dev_to_disk(dev);
1170 
1171 	return sprintf(buf, "%d\n", queue_alignment_offset(disk->queue));
1172 }
1173 
disk_discard_alignment_show(struct device * dev,struct device_attribute * attr,char * buf)1174 static ssize_t disk_discard_alignment_show(struct device *dev,
1175 					   struct device_attribute *attr,
1176 					   char *buf)
1177 {
1178 	struct gendisk *disk = dev_to_disk(dev);
1179 
1180 	return sprintf(buf, "%d\n", queue_discard_alignment(disk->queue));
1181 }
1182 
1183 static DEVICE_ATTR(range, 0444, disk_range_show, NULL);
1184 static DEVICE_ATTR(ext_range, 0444, disk_ext_range_show, NULL);
1185 static DEVICE_ATTR(removable, 0444, disk_removable_show, NULL);
1186 static DEVICE_ATTR(hidden, 0444, disk_hidden_show, NULL);
1187 static DEVICE_ATTR(ro, 0444, disk_ro_show, NULL);
1188 static DEVICE_ATTR(size, 0444, part_size_show, NULL);
1189 static DEVICE_ATTR(alignment_offset, 0444, disk_alignment_offset_show, NULL);
1190 static DEVICE_ATTR(discard_alignment, 0444, disk_discard_alignment_show, NULL);
1191 static DEVICE_ATTR(capability, 0444, disk_capability_show, NULL);
1192 static DEVICE_ATTR(stat, 0444, part_stat_show, NULL);
1193 static DEVICE_ATTR(inflight, 0444, part_inflight_show, NULL);
1194 static DEVICE_ATTR(badblocks, 0644, disk_badblocks_show, disk_badblocks_store);
1195 #ifdef CONFIG_FAIL_MAKE_REQUEST
1196 static struct device_attribute dev_attr_fail =
1197 	__ATTR(make-it-fail, 0644, part_fail_show, part_fail_store);
1198 #endif
1199 #ifdef CONFIG_FAIL_IO_TIMEOUT
1200 static struct device_attribute dev_attr_fail_timeout =
1201 	__ATTR(io-timeout-fail, 0644, part_timeout_show, part_timeout_store);
1202 #endif
1203 
1204 static struct attribute *disk_attrs[] = {
1205 	&dev_attr_range.attr,
1206 	&dev_attr_ext_range.attr,
1207 	&dev_attr_removable.attr,
1208 	&dev_attr_hidden.attr,
1209 	&dev_attr_ro.attr,
1210 	&dev_attr_size.attr,
1211 	&dev_attr_alignment_offset.attr,
1212 	&dev_attr_discard_alignment.attr,
1213 	&dev_attr_capability.attr,
1214 	&dev_attr_stat.attr,
1215 	&dev_attr_inflight.attr,
1216 	&dev_attr_badblocks.attr,
1217 #ifdef CONFIG_FAIL_MAKE_REQUEST
1218 	&dev_attr_fail.attr,
1219 #endif
1220 #ifdef CONFIG_FAIL_IO_TIMEOUT
1221 	&dev_attr_fail_timeout.attr,
1222 #endif
1223 	NULL
1224 };
1225 
disk_visible(struct kobject * kobj,struct attribute * a,int n)1226 static umode_t disk_visible(struct kobject *kobj, struct attribute *a, int n)
1227 {
1228 	struct device *dev = container_of(kobj, typeof(*dev), kobj);
1229 	struct gendisk *disk = dev_to_disk(dev);
1230 
1231 	if (a == &dev_attr_badblocks.attr && !disk->bb)
1232 		return 0;
1233 	return a->mode;
1234 }
1235 
1236 static struct attribute_group disk_attr_group = {
1237 	.attrs = disk_attrs,
1238 	.is_visible = disk_visible,
1239 };
1240 
1241 static const struct attribute_group *disk_attr_groups[] = {
1242 	&disk_attr_group,
1243 	NULL
1244 };
1245 
1246 /**
1247  * disk_replace_part_tbl - replace disk->part_tbl in RCU-safe way
1248  * @disk: disk to replace part_tbl for
1249  * @new_ptbl: new part_tbl to install
1250  *
1251  * Replace disk->part_tbl with @new_ptbl in RCU-safe way.  The
1252  * original ptbl is freed using RCU callback.
1253  *
1254  * LOCKING:
1255  * Matching bd_mutex locked or the caller is the only user of @disk.
1256  */
disk_replace_part_tbl(struct gendisk * disk,struct disk_part_tbl * new_ptbl)1257 static void disk_replace_part_tbl(struct gendisk *disk,
1258 				  struct disk_part_tbl *new_ptbl)
1259 {
1260 	struct disk_part_tbl *old_ptbl =
1261 		rcu_dereference_protected(disk->part_tbl, 1);
1262 
1263 	rcu_assign_pointer(disk->part_tbl, new_ptbl);
1264 
1265 	if (old_ptbl) {
1266 		rcu_assign_pointer(old_ptbl->last_lookup, NULL);
1267 		kfree_rcu(old_ptbl, rcu_head);
1268 	}
1269 }
1270 
1271 /**
1272  * disk_expand_part_tbl - expand disk->part_tbl
1273  * @disk: disk to expand part_tbl for
1274  * @partno: expand such that this partno can fit in
1275  *
1276  * Expand disk->part_tbl such that @partno can fit in.  disk->part_tbl
1277  * uses RCU to allow unlocked dereferencing for stats and other stuff.
1278  *
1279  * LOCKING:
1280  * Matching bd_mutex locked or the caller is the only user of @disk.
1281  * Might sleep.
1282  *
1283  * RETURNS:
1284  * 0 on success, -errno on failure.
1285  */
disk_expand_part_tbl(struct gendisk * disk,int partno)1286 int disk_expand_part_tbl(struct gendisk *disk, int partno)
1287 {
1288 	struct disk_part_tbl *old_ptbl =
1289 		rcu_dereference_protected(disk->part_tbl, 1);
1290 	struct disk_part_tbl *new_ptbl;
1291 	int len = old_ptbl ? old_ptbl->len : 0;
1292 	int i, target;
1293 
1294 	/*
1295 	 * check for int overflow, since we can get here from blkpg_ioctl()
1296 	 * with a user passed 'partno'.
1297 	 */
1298 	target = partno + 1;
1299 	if (target < 0)
1300 		return -EINVAL;
1301 
1302 	/* disk_max_parts() is zero during initialization, ignore if so */
1303 	if (disk_max_parts(disk) && target > disk_max_parts(disk))
1304 		return -EINVAL;
1305 
1306 	if (target <= len)
1307 		return 0;
1308 
1309 	new_ptbl = kzalloc_node(struct_size(new_ptbl, part, target), GFP_KERNEL,
1310 				disk->node_id);
1311 	if (!new_ptbl)
1312 		return -ENOMEM;
1313 
1314 	new_ptbl->len = target;
1315 
1316 	for (i = 0; i < len; i++)
1317 		rcu_assign_pointer(new_ptbl->part[i], old_ptbl->part[i]);
1318 
1319 	disk_replace_part_tbl(disk, new_ptbl);
1320 	return 0;
1321 }
1322 
disk_release(struct device * dev)1323 static void disk_release(struct device *dev)
1324 {
1325 	struct gendisk *disk = dev_to_disk(dev);
1326 
1327 	blk_free_devt(dev->devt);
1328 	disk_release_events(disk);
1329 	kfree(disk->random);
1330 	disk_replace_part_tbl(disk, NULL);
1331 	hd_free_part(&disk->part0);
1332 	if (disk->queue)
1333 		blk_put_queue(disk->queue);
1334 	kfree(disk);
1335 }
1336 struct class block_class = {
1337 	.name		= "block",
1338 };
1339 
block_devnode(struct device * dev,umode_t * mode,kuid_t * uid,kgid_t * gid)1340 static char *block_devnode(struct device *dev, umode_t *mode,
1341 			   kuid_t *uid, kgid_t *gid)
1342 {
1343 	struct gendisk *disk = dev_to_disk(dev);
1344 
1345 	if (disk->devnode)
1346 		return disk->devnode(disk, mode);
1347 	return NULL;
1348 }
1349 
1350 static const struct device_type disk_type = {
1351 	.name		= "disk",
1352 	.groups		= disk_attr_groups,
1353 	.release	= disk_release,
1354 	.devnode	= block_devnode,
1355 };
1356 
1357 #ifdef CONFIG_PROC_FS
1358 /*
1359  * aggregate disk stat collector.  Uses the same stats that the sysfs
1360  * entries do, above, but makes them available through one seq_file.
1361  *
1362  * The output looks suspiciously like /proc/partitions with a bunch of
1363  * extra fields.
1364  */
diskstats_show(struct seq_file * seqf,void * v)1365 static int diskstats_show(struct seq_file *seqf, void *v)
1366 {
1367 	struct gendisk *gp = v;
1368 	struct disk_part_iter piter;
1369 	struct hd_struct *hd;
1370 	char buf[BDEVNAME_SIZE];
1371 	unsigned int inflight;
1372 
1373 	/*
1374 	if (&disk_to_dev(gp)->kobj.entry == block_class.devices.next)
1375 		seq_puts(seqf,	"major minor name"
1376 				"     rio rmerge rsect ruse wio wmerge "
1377 				"wsect wuse running use aveq"
1378 				"\n\n");
1379 	*/
1380 
1381 	disk_part_iter_init(&piter, gp, DISK_PITER_INCL_EMPTY_PART0);
1382 	while ((hd = disk_part_iter_next(&piter))) {
1383 		inflight = part_in_flight(gp->queue, hd);
1384 		seq_printf(seqf, "%4d %7d %s "
1385 			   "%lu %lu %lu %u "
1386 			   "%lu %lu %lu %u "
1387 			   "%u %u %u "
1388 			   "%lu %lu %lu %u\n",
1389 			   MAJOR(part_devt(hd)), MINOR(part_devt(hd)),
1390 			   disk_name(gp, hd->partno, buf),
1391 			   part_stat_read(hd, ios[STAT_READ]),
1392 			   part_stat_read(hd, merges[STAT_READ]),
1393 			   part_stat_read(hd, sectors[STAT_READ]),
1394 			   (unsigned int)part_stat_read_msecs(hd, STAT_READ),
1395 			   part_stat_read(hd, ios[STAT_WRITE]),
1396 			   part_stat_read(hd, merges[STAT_WRITE]),
1397 			   part_stat_read(hd, sectors[STAT_WRITE]),
1398 			   (unsigned int)part_stat_read_msecs(hd, STAT_WRITE),
1399 			   inflight,
1400 			   jiffies_to_msecs(part_stat_read(hd, io_ticks)),
1401 			   jiffies_to_msecs(part_stat_read(hd, time_in_queue)),
1402 			   part_stat_read(hd, ios[STAT_DISCARD]),
1403 			   part_stat_read(hd, merges[STAT_DISCARD]),
1404 			   part_stat_read(hd, sectors[STAT_DISCARD]),
1405 			   (unsigned int)part_stat_read_msecs(hd, STAT_DISCARD)
1406 			);
1407 	}
1408 	disk_part_iter_exit(&piter);
1409 
1410 	return 0;
1411 }
1412 
1413 static const struct seq_operations diskstats_op = {
1414 	.start	= disk_seqf_start,
1415 	.next	= disk_seqf_next,
1416 	.stop	= disk_seqf_stop,
1417 	.show	= diskstats_show
1418 };
1419 
proc_genhd_init(void)1420 static int __init proc_genhd_init(void)
1421 {
1422 	proc_create_seq("diskstats", 0, NULL, &diskstats_op);
1423 	proc_create_seq("partitions", 0, NULL, &partitions_op);
1424 	return 0;
1425 }
1426 module_init(proc_genhd_init);
1427 #endif /* CONFIG_PROC_FS */
1428 
blk_lookup_devt(const char * name,int partno)1429 dev_t blk_lookup_devt(const char *name, int partno)
1430 {
1431 	dev_t devt = MKDEV(0, 0);
1432 	struct class_dev_iter iter;
1433 	struct device *dev;
1434 
1435 	class_dev_iter_init(&iter, &block_class, NULL, &disk_type);
1436 	while ((dev = class_dev_iter_next(&iter))) {
1437 		struct gendisk *disk = dev_to_disk(dev);
1438 		struct hd_struct *part;
1439 
1440 		if (strcmp(dev_name(dev), name))
1441 			continue;
1442 
1443 		if (partno < disk->minors) {
1444 			/* We need to return the right devno, even
1445 			 * if the partition doesn't exist yet.
1446 			 */
1447 			devt = MKDEV(MAJOR(dev->devt),
1448 				     MINOR(dev->devt) + partno);
1449 			break;
1450 		}
1451 		part = disk_get_part(disk, partno);
1452 		if (part) {
1453 			devt = part_devt(part);
1454 			disk_put_part(part);
1455 			break;
1456 		}
1457 		disk_put_part(part);
1458 	}
1459 	class_dev_iter_exit(&iter);
1460 	return devt;
1461 }
1462 EXPORT_SYMBOL(blk_lookup_devt);
1463 
__alloc_disk_node(int minors,int node_id)1464 struct gendisk *__alloc_disk_node(int minors, int node_id)
1465 {
1466 	struct gendisk *disk;
1467 	struct disk_part_tbl *ptbl;
1468 
1469 	if (minors > DISK_MAX_PARTS) {
1470 		printk(KERN_ERR
1471 			"block: can't allocate more than %d partitions\n",
1472 			DISK_MAX_PARTS);
1473 		minors = DISK_MAX_PARTS;
1474 	}
1475 
1476 	disk = kzalloc_node(sizeof(struct gendisk), GFP_KERNEL, node_id);
1477 	if (disk) {
1478 		if (!init_part_stats(&disk->part0)) {
1479 			kfree(disk);
1480 			return NULL;
1481 		}
1482 		init_rwsem(&disk->lookup_sem);
1483 		disk->node_id = node_id;
1484 		if (disk_expand_part_tbl(disk, 0)) {
1485 			free_part_stats(&disk->part0);
1486 			kfree(disk);
1487 			return NULL;
1488 		}
1489 		ptbl = rcu_dereference_protected(disk->part_tbl, 1);
1490 		rcu_assign_pointer(ptbl->part[0], &disk->part0);
1491 
1492 		/*
1493 		 * set_capacity() and get_capacity() currently don't use
1494 		 * seqcounter to read/update the part0->nr_sects. Still init
1495 		 * the counter as we can read the sectors in IO submission
1496 		 * patch using seqence counters.
1497 		 *
1498 		 * TODO: Ideally set_capacity() and get_capacity() should be
1499 		 * converted to make use of bd_mutex and sequence counters.
1500 		 */
1501 		seqcount_init(&disk->part0.nr_sects_seq);
1502 		if (hd_ref_init(&disk->part0)) {
1503 			hd_free_part(&disk->part0);
1504 			kfree(disk);
1505 			return NULL;
1506 		}
1507 
1508 		disk->minors = minors;
1509 		rand_initialize_disk(disk);
1510 		disk_to_dev(disk)->class = &block_class;
1511 		disk_to_dev(disk)->type = &disk_type;
1512 		device_initialize(disk_to_dev(disk));
1513 	}
1514 	return disk;
1515 }
1516 EXPORT_SYMBOL(__alloc_disk_node);
1517 
get_disk_and_module(struct gendisk * disk)1518 struct kobject *get_disk_and_module(struct gendisk *disk)
1519 {
1520 	struct module *owner;
1521 	struct kobject *kobj;
1522 
1523 	if (!disk->fops)
1524 		return NULL;
1525 	owner = disk->fops->owner;
1526 	if (owner && !try_module_get(owner))
1527 		return NULL;
1528 	kobj = kobject_get_unless_zero(&disk_to_dev(disk)->kobj);
1529 	if (kobj == NULL) {
1530 		module_put(owner);
1531 		return NULL;
1532 	}
1533 	return kobj;
1534 
1535 }
1536 EXPORT_SYMBOL(get_disk_and_module);
1537 
put_disk(struct gendisk * disk)1538 void put_disk(struct gendisk *disk)
1539 {
1540 	if (disk)
1541 		kobject_put(&disk_to_dev(disk)->kobj);
1542 }
1543 EXPORT_SYMBOL(put_disk);
1544 
1545 /*
1546  * This is a counterpart of get_disk_and_module() and thus also of
1547  * get_gendisk().
1548  */
put_disk_and_module(struct gendisk * disk)1549 void put_disk_and_module(struct gendisk *disk)
1550 {
1551 	if (disk) {
1552 		struct module *owner = disk->fops->owner;
1553 
1554 		put_disk(disk);
1555 		module_put(owner);
1556 	}
1557 }
1558 EXPORT_SYMBOL(put_disk_and_module);
1559 
set_disk_ro_uevent(struct gendisk * gd,int ro)1560 static void set_disk_ro_uevent(struct gendisk *gd, int ro)
1561 {
1562 	char event[] = "DISK_RO=1";
1563 	char *envp[] = { event, NULL };
1564 
1565 	if (!ro)
1566 		event[8] = '0';
1567 	kobject_uevent_env(&disk_to_dev(gd)->kobj, KOBJ_CHANGE, envp);
1568 }
1569 
set_device_ro(struct block_device * bdev,int flag)1570 void set_device_ro(struct block_device *bdev, int flag)
1571 {
1572 	bdev->bd_part->policy = flag;
1573 }
1574 
1575 EXPORT_SYMBOL(set_device_ro);
1576 
set_disk_ro(struct gendisk * disk,int flag)1577 void set_disk_ro(struct gendisk *disk, int flag)
1578 {
1579 	struct disk_part_iter piter;
1580 	struct hd_struct *part;
1581 
1582 	if (disk->part0.policy != flag) {
1583 		set_disk_ro_uevent(disk, flag);
1584 		disk->part0.policy = flag;
1585 	}
1586 
1587 	disk_part_iter_init(&piter, disk, DISK_PITER_INCL_EMPTY);
1588 	while ((part = disk_part_iter_next(&piter)))
1589 		part->policy = flag;
1590 	disk_part_iter_exit(&piter);
1591 }
1592 
1593 EXPORT_SYMBOL(set_disk_ro);
1594 
bdev_read_only(struct block_device * bdev)1595 int bdev_read_only(struct block_device *bdev)
1596 {
1597 	if (!bdev)
1598 		return 0;
1599 	return bdev->bd_part->policy;
1600 }
1601 
1602 EXPORT_SYMBOL(bdev_read_only);
1603 
invalidate_partition(struct gendisk * disk,int partno)1604 int invalidate_partition(struct gendisk *disk, int partno)
1605 {
1606 	int res = 0;
1607 	struct block_device *bdev = bdget_disk(disk, partno);
1608 	if (bdev) {
1609 		fsync_bdev(bdev);
1610 		res = __invalidate_device(bdev, true);
1611 		bdput(bdev);
1612 	}
1613 	return res;
1614 }
1615 
1616 EXPORT_SYMBOL(invalidate_partition);
1617 
1618 /*
1619  * Disk events - monitor disk events like media change and eject request.
1620  */
1621 struct disk_events {
1622 	struct list_head	node;		/* all disk_event's */
1623 	struct gendisk		*disk;		/* the associated disk */
1624 	spinlock_t		lock;
1625 
1626 	struct mutex		block_mutex;	/* protects blocking */
1627 	int			block;		/* event blocking depth */
1628 	unsigned int		pending;	/* events already sent out */
1629 	unsigned int		clearing;	/* events being cleared */
1630 
1631 	long			poll_msecs;	/* interval, -1 for default */
1632 	struct delayed_work	dwork;
1633 };
1634 
1635 static const char *disk_events_strs[] = {
1636 	[ilog2(DISK_EVENT_MEDIA_CHANGE)]	= "media_change",
1637 	[ilog2(DISK_EVENT_EJECT_REQUEST)]	= "eject_request",
1638 };
1639 
1640 static char *disk_uevents[] = {
1641 	[ilog2(DISK_EVENT_MEDIA_CHANGE)]	= "DISK_MEDIA_CHANGE=1",
1642 	[ilog2(DISK_EVENT_EJECT_REQUEST)]	= "DISK_EJECT_REQUEST=1",
1643 };
1644 
1645 /* list of all disk_events */
1646 static DEFINE_MUTEX(disk_events_mutex);
1647 static LIST_HEAD(disk_events);
1648 
1649 /* disable in-kernel polling by default */
1650 static unsigned long disk_events_dfl_poll_msecs;
1651 
disk_events_poll_jiffies(struct gendisk * disk)1652 static unsigned long disk_events_poll_jiffies(struct gendisk *disk)
1653 {
1654 	struct disk_events *ev = disk->ev;
1655 	long intv_msecs = 0;
1656 
1657 	/*
1658 	 * If device-specific poll interval is set, always use it.  If
1659 	 * the default is being used, poll if the POLL flag is set.
1660 	 */
1661 	if (ev->poll_msecs >= 0)
1662 		intv_msecs = ev->poll_msecs;
1663 	else if (disk->event_flags & DISK_EVENT_FLAG_POLL)
1664 		intv_msecs = disk_events_dfl_poll_msecs;
1665 
1666 	return msecs_to_jiffies(intv_msecs);
1667 }
1668 
1669 /**
1670  * disk_block_events - block and flush disk event checking
1671  * @disk: disk to block events for
1672  *
1673  * On return from this function, it is guaranteed that event checking
1674  * isn't in progress and won't happen until unblocked by
1675  * disk_unblock_events().  Events blocking is counted and the actual
1676  * unblocking happens after the matching number of unblocks are done.
1677  *
1678  * Note that this intentionally does not block event checking from
1679  * disk_clear_events().
1680  *
1681  * CONTEXT:
1682  * Might sleep.
1683  */
disk_block_events(struct gendisk * disk)1684 void disk_block_events(struct gendisk *disk)
1685 {
1686 	struct disk_events *ev = disk->ev;
1687 	unsigned long flags;
1688 	bool cancel;
1689 
1690 	if (!ev)
1691 		return;
1692 
1693 	/*
1694 	 * Outer mutex ensures that the first blocker completes canceling
1695 	 * the event work before further blockers are allowed to finish.
1696 	 */
1697 	mutex_lock(&ev->block_mutex);
1698 
1699 	spin_lock_irqsave(&ev->lock, flags);
1700 	cancel = !ev->block++;
1701 	spin_unlock_irqrestore(&ev->lock, flags);
1702 
1703 	if (cancel)
1704 		cancel_delayed_work_sync(&disk->ev->dwork);
1705 
1706 	mutex_unlock(&ev->block_mutex);
1707 }
1708 
__disk_unblock_events(struct gendisk * disk,bool check_now)1709 static void __disk_unblock_events(struct gendisk *disk, bool check_now)
1710 {
1711 	struct disk_events *ev = disk->ev;
1712 	unsigned long intv;
1713 	unsigned long flags;
1714 
1715 	spin_lock_irqsave(&ev->lock, flags);
1716 
1717 	if (WARN_ON_ONCE(ev->block <= 0))
1718 		goto out_unlock;
1719 
1720 	if (--ev->block)
1721 		goto out_unlock;
1722 
1723 	intv = disk_events_poll_jiffies(disk);
1724 	if (check_now)
1725 		queue_delayed_work(system_freezable_power_efficient_wq,
1726 				&ev->dwork, 0);
1727 	else if (intv)
1728 		queue_delayed_work(system_freezable_power_efficient_wq,
1729 				&ev->dwork, intv);
1730 out_unlock:
1731 	spin_unlock_irqrestore(&ev->lock, flags);
1732 }
1733 
1734 /**
1735  * disk_unblock_events - unblock disk event checking
1736  * @disk: disk to unblock events for
1737  *
1738  * Undo disk_block_events().  When the block count reaches zero, it
1739  * starts events polling if configured.
1740  *
1741  * CONTEXT:
1742  * Don't care.  Safe to call from irq context.
1743  */
disk_unblock_events(struct gendisk * disk)1744 void disk_unblock_events(struct gendisk *disk)
1745 {
1746 	if (disk->ev)
1747 		__disk_unblock_events(disk, false);
1748 }
1749 
1750 /**
1751  * disk_flush_events - schedule immediate event checking and flushing
1752  * @disk: disk to check and flush events for
1753  * @mask: events to flush
1754  *
1755  * Schedule immediate event checking on @disk if not blocked.  Events in
1756  * @mask are scheduled to be cleared from the driver.  Note that this
1757  * doesn't clear the events from @disk->ev.
1758  *
1759  * CONTEXT:
1760  * If @mask is non-zero must be called with bdev->bd_mutex held.
1761  */
disk_flush_events(struct gendisk * disk,unsigned int mask)1762 void disk_flush_events(struct gendisk *disk, unsigned int mask)
1763 {
1764 	struct disk_events *ev = disk->ev;
1765 
1766 	if (!ev)
1767 		return;
1768 
1769 	spin_lock_irq(&ev->lock);
1770 	ev->clearing |= mask;
1771 	if (!ev->block)
1772 		mod_delayed_work(system_freezable_power_efficient_wq,
1773 				&ev->dwork, 0);
1774 	spin_unlock_irq(&ev->lock);
1775 }
1776 
1777 /**
1778  * disk_clear_events - synchronously check, clear and return pending events
1779  * @disk: disk to fetch and clear events from
1780  * @mask: mask of events to be fetched and cleared
1781  *
1782  * Disk events are synchronously checked and pending events in @mask
1783  * are cleared and returned.  This ignores the block count.
1784  *
1785  * CONTEXT:
1786  * Might sleep.
1787  */
disk_clear_events(struct gendisk * disk,unsigned int mask)1788 unsigned int disk_clear_events(struct gendisk *disk, unsigned int mask)
1789 {
1790 	const struct block_device_operations *bdops = disk->fops;
1791 	struct disk_events *ev = disk->ev;
1792 	unsigned int pending;
1793 	unsigned int clearing = mask;
1794 
1795 	if (!ev) {
1796 		/* for drivers still using the old ->media_changed method */
1797 		if ((mask & DISK_EVENT_MEDIA_CHANGE) &&
1798 		    bdops->media_changed && bdops->media_changed(disk))
1799 			return DISK_EVENT_MEDIA_CHANGE;
1800 		return 0;
1801 	}
1802 
1803 	disk_block_events(disk);
1804 
1805 	/*
1806 	 * store the union of mask and ev->clearing on the stack so that the
1807 	 * race with disk_flush_events does not cause ambiguity (ev->clearing
1808 	 * can still be modified even if events are blocked).
1809 	 */
1810 	spin_lock_irq(&ev->lock);
1811 	clearing |= ev->clearing;
1812 	ev->clearing = 0;
1813 	spin_unlock_irq(&ev->lock);
1814 
1815 	disk_check_events(ev, &clearing);
1816 	/*
1817 	 * if ev->clearing is not 0, the disk_flush_events got called in the
1818 	 * middle of this function, so we want to run the workfn without delay.
1819 	 */
1820 	__disk_unblock_events(disk, ev->clearing ? true : false);
1821 
1822 	/* then, fetch and clear pending events */
1823 	spin_lock_irq(&ev->lock);
1824 	pending = ev->pending & mask;
1825 	ev->pending &= ~mask;
1826 	spin_unlock_irq(&ev->lock);
1827 	WARN_ON_ONCE(clearing & mask);
1828 
1829 	return pending;
1830 }
1831 
1832 /*
1833  * Separate this part out so that a different pointer for clearing_ptr can be
1834  * passed in for disk_clear_events.
1835  */
disk_events_workfn(struct work_struct * work)1836 static void disk_events_workfn(struct work_struct *work)
1837 {
1838 	struct delayed_work *dwork = to_delayed_work(work);
1839 	struct disk_events *ev = container_of(dwork, struct disk_events, dwork);
1840 
1841 	disk_check_events(ev, &ev->clearing);
1842 }
1843 
disk_check_events(struct disk_events * ev,unsigned int * clearing_ptr)1844 static void disk_check_events(struct disk_events *ev,
1845 			      unsigned int *clearing_ptr)
1846 {
1847 	struct gendisk *disk = ev->disk;
1848 	char *envp[ARRAY_SIZE(disk_uevents) + 1] = { };
1849 	unsigned int clearing = *clearing_ptr;
1850 	unsigned int events;
1851 	unsigned long intv;
1852 	int nr_events = 0, i;
1853 
1854 	/* check events */
1855 	events = disk->fops->check_events(disk, clearing);
1856 
1857 	/* accumulate pending events and schedule next poll if necessary */
1858 	spin_lock_irq(&ev->lock);
1859 
1860 	events &= ~ev->pending;
1861 	ev->pending |= events;
1862 	*clearing_ptr &= ~clearing;
1863 
1864 	intv = disk_events_poll_jiffies(disk);
1865 	if (!ev->block && intv)
1866 		queue_delayed_work(system_freezable_power_efficient_wq,
1867 				&ev->dwork, intv);
1868 
1869 	spin_unlock_irq(&ev->lock);
1870 
1871 	/*
1872 	 * Tell userland about new events.  Only the events listed in
1873 	 * @disk->events are reported, and only if DISK_EVENT_FLAG_UEVENT
1874 	 * is set. Otherwise, events are processed internally but never
1875 	 * get reported to userland.
1876 	 */
1877 	for (i = 0; i < ARRAY_SIZE(disk_uevents); i++)
1878 		if ((events & disk->events & (1 << i)) &&
1879 		    (disk->event_flags & DISK_EVENT_FLAG_UEVENT))
1880 			envp[nr_events++] = disk_uevents[i];
1881 
1882 	if (nr_events)
1883 		kobject_uevent_env(&disk_to_dev(disk)->kobj, KOBJ_CHANGE, envp);
1884 }
1885 
1886 /*
1887  * A disk events enabled device has the following sysfs nodes under
1888  * its /sys/block/X/ directory.
1889  *
1890  * events		: list of all supported events
1891  * events_async		: list of events which can be detected w/o polling
1892  *			  (always empty, only for backwards compatibility)
1893  * events_poll_msecs	: polling interval, 0: disable, -1: system default
1894  */
__disk_events_show(unsigned int events,char * buf)1895 static ssize_t __disk_events_show(unsigned int events, char *buf)
1896 {
1897 	const char *delim = "";
1898 	ssize_t pos = 0;
1899 	int i;
1900 
1901 	for (i = 0; i < ARRAY_SIZE(disk_events_strs); i++)
1902 		if (events & (1 << i)) {
1903 			pos += sprintf(buf + pos, "%s%s",
1904 				       delim, disk_events_strs[i]);
1905 			delim = " ";
1906 		}
1907 	if (pos)
1908 		pos += sprintf(buf + pos, "\n");
1909 	return pos;
1910 }
1911 
disk_events_show(struct device * dev,struct device_attribute * attr,char * buf)1912 static ssize_t disk_events_show(struct device *dev,
1913 				struct device_attribute *attr, char *buf)
1914 {
1915 	struct gendisk *disk = dev_to_disk(dev);
1916 
1917 	if (!(disk->event_flags & DISK_EVENT_FLAG_UEVENT))
1918 		return 0;
1919 
1920 	return __disk_events_show(disk->events, buf);
1921 }
1922 
disk_events_async_show(struct device * dev,struct device_attribute * attr,char * buf)1923 static ssize_t disk_events_async_show(struct device *dev,
1924 				      struct device_attribute *attr, char *buf)
1925 {
1926 	return 0;
1927 }
1928 
disk_events_poll_msecs_show(struct device * dev,struct device_attribute * attr,char * buf)1929 static ssize_t disk_events_poll_msecs_show(struct device *dev,
1930 					   struct device_attribute *attr,
1931 					   char *buf)
1932 {
1933 	struct gendisk *disk = dev_to_disk(dev);
1934 
1935 	if (!disk->ev)
1936 		return sprintf(buf, "-1\n");
1937 
1938 	return sprintf(buf, "%ld\n", disk->ev->poll_msecs);
1939 }
1940 
disk_events_poll_msecs_store(struct device * dev,struct device_attribute * attr,const char * buf,size_t count)1941 static ssize_t disk_events_poll_msecs_store(struct device *dev,
1942 					    struct device_attribute *attr,
1943 					    const char *buf, size_t count)
1944 {
1945 	struct gendisk *disk = dev_to_disk(dev);
1946 	long intv;
1947 
1948 	if (!count || !sscanf(buf, "%ld", &intv))
1949 		return -EINVAL;
1950 
1951 	if (intv < 0 && intv != -1)
1952 		return -EINVAL;
1953 
1954 	if (!disk->ev)
1955 		return -ENODEV;
1956 
1957 	disk_block_events(disk);
1958 	disk->ev->poll_msecs = intv;
1959 	__disk_unblock_events(disk, true);
1960 
1961 	return count;
1962 }
1963 
1964 static const DEVICE_ATTR(events, 0444, disk_events_show, NULL);
1965 static const DEVICE_ATTR(events_async, 0444, disk_events_async_show, NULL);
1966 static const DEVICE_ATTR(events_poll_msecs, 0644,
1967 			 disk_events_poll_msecs_show,
1968 			 disk_events_poll_msecs_store);
1969 
1970 static const struct attribute *disk_events_attrs[] = {
1971 	&dev_attr_events.attr,
1972 	&dev_attr_events_async.attr,
1973 	&dev_attr_events_poll_msecs.attr,
1974 	NULL,
1975 };
1976 
1977 /*
1978  * The default polling interval can be specified by the kernel
1979  * parameter block.events_dfl_poll_msecs which defaults to 0
1980  * (disable).  This can also be modified runtime by writing to
1981  * /sys/module/block/parameters/events_dfl_poll_msecs.
1982  */
disk_events_set_dfl_poll_msecs(const char * val,const struct kernel_param * kp)1983 static int disk_events_set_dfl_poll_msecs(const char *val,
1984 					  const struct kernel_param *kp)
1985 {
1986 	struct disk_events *ev;
1987 	int ret;
1988 
1989 	ret = param_set_ulong(val, kp);
1990 	if (ret < 0)
1991 		return ret;
1992 
1993 	mutex_lock(&disk_events_mutex);
1994 
1995 	list_for_each_entry(ev, &disk_events, node)
1996 		disk_flush_events(ev->disk, 0);
1997 
1998 	mutex_unlock(&disk_events_mutex);
1999 
2000 	return 0;
2001 }
2002 
2003 static const struct kernel_param_ops disk_events_dfl_poll_msecs_param_ops = {
2004 	.set	= disk_events_set_dfl_poll_msecs,
2005 	.get	= param_get_ulong,
2006 };
2007 
2008 #undef MODULE_PARAM_PREFIX
2009 #define MODULE_PARAM_PREFIX	"block."
2010 
2011 module_param_cb(events_dfl_poll_msecs, &disk_events_dfl_poll_msecs_param_ops,
2012 		&disk_events_dfl_poll_msecs, 0644);
2013 
2014 /*
2015  * disk_{alloc|add|del|release}_events - initialize and destroy disk_events.
2016  */
disk_alloc_events(struct gendisk * disk)2017 static void disk_alloc_events(struct gendisk *disk)
2018 {
2019 	struct disk_events *ev;
2020 
2021 	if (!disk->fops->check_events || !disk->events)
2022 		return;
2023 
2024 	ev = kzalloc(sizeof(*ev), GFP_KERNEL);
2025 	if (!ev) {
2026 		pr_warn("%s: failed to initialize events\n", disk->disk_name);
2027 		return;
2028 	}
2029 
2030 	INIT_LIST_HEAD(&ev->node);
2031 	ev->disk = disk;
2032 	spin_lock_init(&ev->lock);
2033 	mutex_init(&ev->block_mutex);
2034 	ev->block = 1;
2035 	ev->poll_msecs = -1;
2036 	INIT_DELAYED_WORK(&ev->dwork, disk_events_workfn);
2037 
2038 	disk->ev = ev;
2039 }
2040 
disk_add_events(struct gendisk * disk)2041 static void disk_add_events(struct gendisk *disk)
2042 {
2043 	/* FIXME: error handling */
2044 	if (sysfs_create_files(&disk_to_dev(disk)->kobj, disk_events_attrs) < 0)
2045 		pr_warn("%s: failed to create sysfs files for events\n",
2046 			disk->disk_name);
2047 
2048 	if (!disk->ev)
2049 		return;
2050 
2051 	mutex_lock(&disk_events_mutex);
2052 	list_add_tail(&disk->ev->node, &disk_events);
2053 	mutex_unlock(&disk_events_mutex);
2054 
2055 	/*
2056 	 * Block count is initialized to 1 and the following initial
2057 	 * unblock kicks it into action.
2058 	 */
2059 	__disk_unblock_events(disk, true);
2060 }
2061 
disk_del_events(struct gendisk * disk)2062 static void disk_del_events(struct gendisk *disk)
2063 {
2064 	if (disk->ev) {
2065 		disk_block_events(disk);
2066 
2067 		mutex_lock(&disk_events_mutex);
2068 		list_del_init(&disk->ev->node);
2069 		mutex_unlock(&disk_events_mutex);
2070 	}
2071 
2072 	sysfs_remove_files(&disk_to_dev(disk)->kobj, disk_events_attrs);
2073 }
2074 
disk_release_events(struct gendisk * disk)2075 static void disk_release_events(struct gendisk *disk)
2076 {
2077 	/* the block count should be 1 from disk_del_events() */
2078 	WARN_ON_ONCE(disk->ev && disk->ev->block != 1);
2079 	kfree(disk->ev);
2080 }
2081