xref: /openbmc/linux/drivers/md/dm-table.c (revision 6774def6)
1 /*
2  * Copyright (C) 2001 Sistina Software (UK) Limited.
3  * Copyright (C) 2004-2008 Red Hat, Inc. All rights reserved.
4  *
5  * This file is released under the GPL.
6  */
7 
8 #include "dm.h"
9 
10 #include <linux/module.h>
11 #include <linux/vmalloc.h>
12 #include <linux/blkdev.h>
13 #include <linux/namei.h>
14 #include <linux/ctype.h>
15 #include <linux/string.h>
16 #include <linux/slab.h>
17 #include <linux/interrupt.h>
18 #include <linux/mutex.h>
19 #include <linux/delay.h>
20 #include <linux/atomic.h>
21 
22 #define DM_MSG_PREFIX "table"
23 
24 #define MAX_DEPTH 16
25 #define NODE_SIZE L1_CACHE_BYTES
26 #define KEYS_PER_NODE (NODE_SIZE / sizeof(sector_t))
27 #define CHILDREN_PER_NODE (KEYS_PER_NODE + 1)
28 
29 struct dm_table {
30 	struct mapped_device *md;
31 	unsigned type;
32 
33 	/* btree table */
34 	unsigned int depth;
35 	unsigned int counts[MAX_DEPTH];	/* in nodes */
36 	sector_t *index[MAX_DEPTH];
37 
38 	unsigned int num_targets;
39 	unsigned int num_allocated;
40 	sector_t *highs;
41 	struct dm_target *targets;
42 
43 	struct target_type *immutable_target_type;
44 	unsigned integrity_supported:1;
45 	unsigned singleton:1;
46 
47 	/*
48 	 * Indicates the rw permissions for the new logical
49 	 * device.  This should be a combination of FMODE_READ
50 	 * and FMODE_WRITE.
51 	 */
52 	fmode_t mode;
53 
54 	/* a list of devices used by this table */
55 	struct list_head devices;
56 
57 	/* events get handed up using this callback */
58 	void (*event_fn)(void *);
59 	void *event_context;
60 
61 	struct dm_md_mempools *mempools;
62 
63 	struct list_head target_callbacks;
64 };
65 
66 /*
67  * Similar to ceiling(log_size(n))
68  */
69 static unsigned int int_log(unsigned int n, unsigned int base)
70 {
71 	int result = 0;
72 
73 	while (n > 1) {
74 		n = dm_div_up(n, base);
75 		result++;
76 	}
77 
78 	return result;
79 }
80 
81 /*
82  * Calculate the index of the child node of the n'th node k'th key.
83  */
84 static inline unsigned int get_child(unsigned int n, unsigned int k)
85 {
86 	return (n * CHILDREN_PER_NODE) + k;
87 }
88 
89 /*
90  * Return the n'th node of level l from table t.
91  */
92 static inline sector_t *get_node(struct dm_table *t,
93 				 unsigned int l, unsigned int n)
94 {
95 	return t->index[l] + (n * KEYS_PER_NODE);
96 }
97 
98 /*
99  * Return the highest key that you could lookup from the n'th
100  * node on level l of the btree.
101  */
102 static sector_t high(struct dm_table *t, unsigned int l, unsigned int n)
103 {
104 	for (; l < t->depth - 1; l++)
105 		n = get_child(n, CHILDREN_PER_NODE - 1);
106 
107 	if (n >= t->counts[l])
108 		return (sector_t) - 1;
109 
110 	return get_node(t, l, n)[KEYS_PER_NODE - 1];
111 }
112 
113 /*
114  * Fills in a level of the btree based on the highs of the level
115  * below it.
116  */
117 static int setup_btree_index(unsigned int l, struct dm_table *t)
118 {
119 	unsigned int n, k;
120 	sector_t *node;
121 
122 	for (n = 0U; n < t->counts[l]; n++) {
123 		node = get_node(t, l, n);
124 
125 		for (k = 0U; k < KEYS_PER_NODE; k++)
126 			node[k] = high(t, l + 1, get_child(n, k));
127 	}
128 
129 	return 0;
130 }
131 
132 void *dm_vcalloc(unsigned long nmemb, unsigned long elem_size)
133 {
134 	unsigned long size;
135 	void *addr;
136 
137 	/*
138 	 * Check that we're not going to overflow.
139 	 */
140 	if (nmemb > (ULONG_MAX / elem_size))
141 		return NULL;
142 
143 	size = nmemb * elem_size;
144 	addr = vzalloc(size);
145 
146 	return addr;
147 }
148 EXPORT_SYMBOL(dm_vcalloc);
149 
150 /*
151  * highs, and targets are managed as dynamic arrays during a
152  * table load.
153  */
154 static int alloc_targets(struct dm_table *t, unsigned int num)
155 {
156 	sector_t *n_highs;
157 	struct dm_target *n_targets;
158 
159 	/*
160 	 * Allocate both the target array and offset array at once.
161 	 * Append an empty entry to catch sectors beyond the end of
162 	 * the device.
163 	 */
164 	n_highs = (sector_t *) dm_vcalloc(num + 1, sizeof(struct dm_target) +
165 					  sizeof(sector_t));
166 	if (!n_highs)
167 		return -ENOMEM;
168 
169 	n_targets = (struct dm_target *) (n_highs + num);
170 
171 	memset(n_highs, -1, sizeof(*n_highs) * num);
172 	vfree(t->highs);
173 
174 	t->num_allocated = num;
175 	t->highs = n_highs;
176 	t->targets = n_targets;
177 
178 	return 0;
179 }
180 
181 int dm_table_create(struct dm_table **result, fmode_t mode,
182 		    unsigned num_targets, struct mapped_device *md)
183 {
184 	struct dm_table *t = kzalloc(sizeof(*t), GFP_KERNEL);
185 
186 	if (!t)
187 		return -ENOMEM;
188 
189 	INIT_LIST_HEAD(&t->devices);
190 	INIT_LIST_HEAD(&t->target_callbacks);
191 
192 	if (!num_targets)
193 		num_targets = KEYS_PER_NODE;
194 
195 	num_targets = dm_round_up(num_targets, KEYS_PER_NODE);
196 
197 	if (!num_targets) {
198 		kfree(t);
199 		return -ENOMEM;
200 	}
201 
202 	if (alloc_targets(t, num_targets)) {
203 		kfree(t);
204 		return -ENOMEM;
205 	}
206 
207 	t->mode = mode;
208 	t->md = md;
209 	*result = t;
210 	return 0;
211 }
212 
213 static void free_devices(struct list_head *devices, struct mapped_device *md)
214 {
215 	struct list_head *tmp, *next;
216 
217 	list_for_each_safe(tmp, next, devices) {
218 		struct dm_dev_internal *dd =
219 		    list_entry(tmp, struct dm_dev_internal, list);
220 		DMWARN("%s: dm_table_destroy: dm_put_device call missing for %s",
221 		       dm_device_name(md), dd->dm_dev->name);
222 		dm_put_table_device(md, dd->dm_dev);
223 		kfree(dd);
224 	}
225 }
226 
227 void dm_table_destroy(struct dm_table *t)
228 {
229 	unsigned int i;
230 
231 	if (!t)
232 		return;
233 
234 	/* free the indexes */
235 	if (t->depth >= 2)
236 		vfree(t->index[t->depth - 2]);
237 
238 	/* free the targets */
239 	for (i = 0; i < t->num_targets; i++) {
240 		struct dm_target *tgt = t->targets + i;
241 
242 		if (tgt->type->dtr)
243 			tgt->type->dtr(tgt);
244 
245 		dm_put_target_type(tgt->type);
246 	}
247 
248 	vfree(t->highs);
249 
250 	/* free the device list */
251 	free_devices(&t->devices, t->md);
252 
253 	dm_free_md_mempools(t->mempools);
254 
255 	kfree(t);
256 }
257 
258 /*
259  * See if we've already got a device in the list.
260  */
261 static struct dm_dev_internal *find_device(struct list_head *l, dev_t dev)
262 {
263 	struct dm_dev_internal *dd;
264 
265 	list_for_each_entry (dd, l, list)
266 		if (dd->dm_dev->bdev->bd_dev == dev)
267 			return dd;
268 
269 	return NULL;
270 }
271 
272 /*
273  * If possible, this checks an area of a destination device is invalid.
274  */
275 static int device_area_is_invalid(struct dm_target *ti, struct dm_dev *dev,
276 				  sector_t start, sector_t len, void *data)
277 {
278 	struct request_queue *q;
279 	struct queue_limits *limits = data;
280 	struct block_device *bdev = dev->bdev;
281 	sector_t dev_size =
282 		i_size_read(bdev->bd_inode) >> SECTOR_SHIFT;
283 	unsigned short logical_block_size_sectors =
284 		limits->logical_block_size >> SECTOR_SHIFT;
285 	char b[BDEVNAME_SIZE];
286 
287 	/*
288 	 * Some devices exist without request functions,
289 	 * such as loop devices not yet bound to backing files.
290 	 * Forbid the use of such devices.
291 	 */
292 	q = bdev_get_queue(bdev);
293 	if (!q || !q->make_request_fn) {
294 		DMWARN("%s: %s is not yet initialised: "
295 		       "start=%llu, len=%llu, dev_size=%llu",
296 		       dm_device_name(ti->table->md), bdevname(bdev, b),
297 		       (unsigned long long)start,
298 		       (unsigned long long)len,
299 		       (unsigned long long)dev_size);
300 		return 1;
301 	}
302 
303 	if (!dev_size)
304 		return 0;
305 
306 	if ((start >= dev_size) || (start + len > dev_size)) {
307 		DMWARN("%s: %s too small for target: "
308 		       "start=%llu, len=%llu, dev_size=%llu",
309 		       dm_device_name(ti->table->md), bdevname(bdev, b),
310 		       (unsigned long long)start,
311 		       (unsigned long long)len,
312 		       (unsigned long long)dev_size);
313 		return 1;
314 	}
315 
316 	if (logical_block_size_sectors <= 1)
317 		return 0;
318 
319 	if (start & (logical_block_size_sectors - 1)) {
320 		DMWARN("%s: start=%llu not aligned to h/w "
321 		       "logical block size %u of %s",
322 		       dm_device_name(ti->table->md),
323 		       (unsigned long long)start,
324 		       limits->logical_block_size, bdevname(bdev, b));
325 		return 1;
326 	}
327 
328 	if (len & (logical_block_size_sectors - 1)) {
329 		DMWARN("%s: len=%llu not aligned to h/w "
330 		       "logical block size %u of %s",
331 		       dm_device_name(ti->table->md),
332 		       (unsigned long long)len,
333 		       limits->logical_block_size, bdevname(bdev, b));
334 		return 1;
335 	}
336 
337 	return 0;
338 }
339 
340 /*
341  * This upgrades the mode on an already open dm_dev, being
342  * careful to leave things as they were if we fail to reopen the
343  * device and not to touch the existing bdev field in case
344  * it is accessed concurrently inside dm_table_any_congested().
345  */
346 static int upgrade_mode(struct dm_dev_internal *dd, fmode_t new_mode,
347 			struct mapped_device *md)
348 {
349 	int r;
350 	struct dm_dev *old_dev, *new_dev;
351 
352 	old_dev = dd->dm_dev;
353 
354 	r = dm_get_table_device(md, dd->dm_dev->bdev->bd_dev,
355 				dd->dm_dev->mode | new_mode, &new_dev);
356 	if (r)
357 		return r;
358 
359 	dd->dm_dev = new_dev;
360 	dm_put_table_device(md, old_dev);
361 
362 	return 0;
363 }
364 
365 /*
366  * Add a device to the list, or just increment the usage count if
367  * it's already present.
368  */
369 int dm_get_device(struct dm_target *ti, const char *path, fmode_t mode,
370 		  struct dm_dev **result)
371 {
372 	int r;
373 	dev_t uninitialized_var(dev);
374 	struct dm_dev_internal *dd;
375 	unsigned int major, minor;
376 	struct dm_table *t = ti->table;
377 	char dummy;
378 
379 	BUG_ON(!t);
380 
381 	if (sscanf(path, "%u:%u%c", &major, &minor, &dummy) == 2) {
382 		/* Extract the major/minor numbers */
383 		dev = MKDEV(major, minor);
384 		if (MAJOR(dev) != major || MINOR(dev) != minor)
385 			return -EOVERFLOW;
386 	} else {
387 		/* convert the path to a device */
388 		struct block_device *bdev = lookup_bdev(path);
389 
390 		if (IS_ERR(bdev))
391 			return PTR_ERR(bdev);
392 		dev = bdev->bd_dev;
393 		bdput(bdev);
394 	}
395 
396 	dd = find_device(&t->devices, dev);
397 	if (!dd) {
398 		dd = kmalloc(sizeof(*dd), GFP_KERNEL);
399 		if (!dd)
400 			return -ENOMEM;
401 
402 		if ((r = dm_get_table_device(t->md, dev, mode, &dd->dm_dev))) {
403 			kfree(dd);
404 			return r;
405 		}
406 
407 		atomic_set(&dd->count, 0);
408 		list_add(&dd->list, &t->devices);
409 
410 	} else if (dd->dm_dev->mode != (mode | dd->dm_dev->mode)) {
411 		r = upgrade_mode(dd, mode, t->md);
412 		if (r)
413 			return r;
414 	}
415 	atomic_inc(&dd->count);
416 
417 	*result = dd->dm_dev;
418 	return 0;
419 }
420 EXPORT_SYMBOL(dm_get_device);
421 
422 static int dm_set_device_limits(struct dm_target *ti, struct dm_dev *dev,
423 				sector_t start, sector_t len, void *data)
424 {
425 	struct queue_limits *limits = data;
426 	struct block_device *bdev = dev->bdev;
427 	struct request_queue *q = bdev_get_queue(bdev);
428 	char b[BDEVNAME_SIZE];
429 
430 	if (unlikely(!q)) {
431 		DMWARN("%s: Cannot set limits for nonexistent device %s",
432 		       dm_device_name(ti->table->md), bdevname(bdev, b));
433 		return 0;
434 	}
435 
436 	if (bdev_stack_limits(limits, bdev, start) < 0)
437 		DMWARN("%s: adding target device %s caused an alignment inconsistency: "
438 		       "physical_block_size=%u, logical_block_size=%u, "
439 		       "alignment_offset=%u, start=%llu",
440 		       dm_device_name(ti->table->md), bdevname(bdev, b),
441 		       q->limits.physical_block_size,
442 		       q->limits.logical_block_size,
443 		       q->limits.alignment_offset,
444 		       (unsigned long long) start << SECTOR_SHIFT);
445 
446 	/*
447 	 * Check if merge fn is supported.
448 	 * If not we'll force DM to use PAGE_SIZE or
449 	 * smaller I/O, just to be safe.
450 	 */
451 	if (dm_queue_merge_is_compulsory(q) && !ti->type->merge)
452 		blk_limits_max_hw_sectors(limits,
453 					  (unsigned int) (PAGE_SIZE >> 9));
454 	return 0;
455 }
456 
457 /*
458  * Decrement a device's use count and remove it if necessary.
459  */
460 void dm_put_device(struct dm_target *ti, struct dm_dev *d)
461 {
462 	int found = 0;
463 	struct list_head *devices = &ti->table->devices;
464 	struct dm_dev_internal *dd;
465 
466 	list_for_each_entry(dd, devices, list) {
467 		if (dd->dm_dev == d) {
468 			found = 1;
469 			break;
470 		}
471 	}
472 	if (!found) {
473 		DMWARN("%s: device %s not in table devices list",
474 		       dm_device_name(ti->table->md), d->name);
475 		return;
476 	}
477 	if (atomic_dec_and_test(&dd->count)) {
478 		dm_put_table_device(ti->table->md, d);
479 		list_del(&dd->list);
480 		kfree(dd);
481 	}
482 }
483 EXPORT_SYMBOL(dm_put_device);
484 
485 /*
486  * Checks to see if the target joins onto the end of the table.
487  */
488 static int adjoin(struct dm_table *table, struct dm_target *ti)
489 {
490 	struct dm_target *prev;
491 
492 	if (!table->num_targets)
493 		return !ti->begin;
494 
495 	prev = &table->targets[table->num_targets - 1];
496 	return (ti->begin == (prev->begin + prev->len));
497 }
498 
499 /*
500  * Used to dynamically allocate the arg array.
501  *
502  * We do first allocation with GFP_NOIO because dm-mpath and dm-thin must
503  * process messages even if some device is suspended. These messages have a
504  * small fixed number of arguments.
505  *
506  * On the other hand, dm-switch needs to process bulk data using messages and
507  * excessive use of GFP_NOIO could cause trouble.
508  */
509 static char **realloc_argv(unsigned *array_size, char **old_argv)
510 {
511 	char **argv;
512 	unsigned new_size;
513 	gfp_t gfp;
514 
515 	if (*array_size) {
516 		new_size = *array_size * 2;
517 		gfp = GFP_KERNEL;
518 	} else {
519 		new_size = 8;
520 		gfp = GFP_NOIO;
521 	}
522 	argv = kmalloc(new_size * sizeof(*argv), gfp);
523 	if (argv) {
524 		memcpy(argv, old_argv, *array_size * sizeof(*argv));
525 		*array_size = new_size;
526 	}
527 
528 	kfree(old_argv);
529 	return argv;
530 }
531 
532 /*
533  * Destructively splits up the argument list to pass to ctr.
534  */
535 int dm_split_args(int *argc, char ***argvp, char *input)
536 {
537 	char *start, *end = input, *out, **argv = NULL;
538 	unsigned array_size = 0;
539 
540 	*argc = 0;
541 
542 	if (!input) {
543 		*argvp = NULL;
544 		return 0;
545 	}
546 
547 	argv = realloc_argv(&array_size, argv);
548 	if (!argv)
549 		return -ENOMEM;
550 
551 	while (1) {
552 		/* Skip whitespace */
553 		start = skip_spaces(end);
554 
555 		if (!*start)
556 			break;	/* success, we hit the end */
557 
558 		/* 'out' is used to remove any back-quotes */
559 		end = out = start;
560 		while (*end) {
561 			/* Everything apart from '\0' can be quoted */
562 			if (*end == '\\' && *(end + 1)) {
563 				*out++ = *(end + 1);
564 				end += 2;
565 				continue;
566 			}
567 
568 			if (isspace(*end))
569 				break;	/* end of token */
570 
571 			*out++ = *end++;
572 		}
573 
574 		/* have we already filled the array ? */
575 		if ((*argc + 1) > array_size) {
576 			argv = realloc_argv(&array_size, argv);
577 			if (!argv)
578 				return -ENOMEM;
579 		}
580 
581 		/* we know this is whitespace */
582 		if (*end)
583 			end++;
584 
585 		/* terminate the string and put it in the array */
586 		*out = '\0';
587 		argv[*argc] = start;
588 		(*argc)++;
589 	}
590 
591 	*argvp = argv;
592 	return 0;
593 }
594 
595 /*
596  * Impose necessary and sufficient conditions on a devices's table such
597  * that any incoming bio which respects its logical_block_size can be
598  * processed successfully.  If it falls across the boundary between
599  * two or more targets, the size of each piece it gets split into must
600  * be compatible with the logical_block_size of the target processing it.
601  */
602 static int validate_hardware_logical_block_alignment(struct dm_table *table,
603 						 struct queue_limits *limits)
604 {
605 	/*
606 	 * This function uses arithmetic modulo the logical_block_size
607 	 * (in units of 512-byte sectors).
608 	 */
609 	unsigned short device_logical_block_size_sects =
610 		limits->logical_block_size >> SECTOR_SHIFT;
611 
612 	/*
613 	 * Offset of the start of the next table entry, mod logical_block_size.
614 	 */
615 	unsigned short next_target_start = 0;
616 
617 	/*
618 	 * Given an aligned bio that extends beyond the end of a
619 	 * target, how many sectors must the next target handle?
620 	 */
621 	unsigned short remaining = 0;
622 
623 	struct dm_target *uninitialized_var(ti);
624 	struct queue_limits ti_limits;
625 	unsigned i = 0;
626 
627 	/*
628 	 * Check each entry in the table in turn.
629 	 */
630 	while (i < dm_table_get_num_targets(table)) {
631 		ti = dm_table_get_target(table, i++);
632 
633 		blk_set_stacking_limits(&ti_limits);
634 
635 		/* combine all target devices' limits */
636 		if (ti->type->iterate_devices)
637 			ti->type->iterate_devices(ti, dm_set_device_limits,
638 						  &ti_limits);
639 
640 		/*
641 		 * If the remaining sectors fall entirely within this
642 		 * table entry are they compatible with its logical_block_size?
643 		 */
644 		if (remaining < ti->len &&
645 		    remaining & ((ti_limits.logical_block_size >>
646 				  SECTOR_SHIFT) - 1))
647 			break;	/* Error */
648 
649 		next_target_start =
650 		    (unsigned short) ((next_target_start + ti->len) &
651 				      (device_logical_block_size_sects - 1));
652 		remaining = next_target_start ?
653 		    device_logical_block_size_sects - next_target_start : 0;
654 	}
655 
656 	if (remaining) {
657 		DMWARN("%s: table line %u (start sect %llu len %llu) "
658 		       "not aligned to h/w logical block size %u",
659 		       dm_device_name(table->md), i,
660 		       (unsigned long long) ti->begin,
661 		       (unsigned long long) ti->len,
662 		       limits->logical_block_size);
663 		return -EINVAL;
664 	}
665 
666 	return 0;
667 }
668 
669 int dm_table_add_target(struct dm_table *t, const char *type,
670 			sector_t start, sector_t len, char *params)
671 {
672 	int r = -EINVAL, argc;
673 	char **argv;
674 	struct dm_target *tgt;
675 
676 	if (t->singleton) {
677 		DMERR("%s: target type %s must appear alone in table",
678 		      dm_device_name(t->md), t->targets->type->name);
679 		return -EINVAL;
680 	}
681 
682 	BUG_ON(t->num_targets >= t->num_allocated);
683 
684 	tgt = t->targets + t->num_targets;
685 	memset(tgt, 0, sizeof(*tgt));
686 
687 	if (!len) {
688 		DMERR("%s: zero-length target", dm_device_name(t->md));
689 		return -EINVAL;
690 	}
691 
692 	tgt->type = dm_get_target_type(type);
693 	if (!tgt->type) {
694 		DMERR("%s: %s: unknown target type", dm_device_name(t->md),
695 		      type);
696 		return -EINVAL;
697 	}
698 
699 	if (dm_target_needs_singleton(tgt->type)) {
700 		if (t->num_targets) {
701 			DMERR("%s: target type %s must appear alone in table",
702 			      dm_device_name(t->md), type);
703 			return -EINVAL;
704 		}
705 		t->singleton = 1;
706 	}
707 
708 	if (dm_target_always_writeable(tgt->type) && !(t->mode & FMODE_WRITE)) {
709 		DMERR("%s: target type %s may not be included in read-only tables",
710 		      dm_device_name(t->md), type);
711 		return -EINVAL;
712 	}
713 
714 	if (t->immutable_target_type) {
715 		if (t->immutable_target_type != tgt->type) {
716 			DMERR("%s: immutable target type %s cannot be mixed with other target types",
717 			      dm_device_name(t->md), t->immutable_target_type->name);
718 			return -EINVAL;
719 		}
720 	} else if (dm_target_is_immutable(tgt->type)) {
721 		if (t->num_targets) {
722 			DMERR("%s: immutable target type %s cannot be mixed with other target types",
723 			      dm_device_name(t->md), tgt->type->name);
724 			return -EINVAL;
725 		}
726 		t->immutable_target_type = tgt->type;
727 	}
728 
729 	tgt->table = t;
730 	tgt->begin = start;
731 	tgt->len = len;
732 	tgt->error = "Unknown error";
733 
734 	/*
735 	 * Does this target adjoin the previous one ?
736 	 */
737 	if (!adjoin(t, tgt)) {
738 		tgt->error = "Gap in table";
739 		r = -EINVAL;
740 		goto bad;
741 	}
742 
743 	r = dm_split_args(&argc, &argv, params);
744 	if (r) {
745 		tgt->error = "couldn't split parameters (insufficient memory)";
746 		goto bad;
747 	}
748 
749 	r = tgt->type->ctr(tgt, argc, argv);
750 	kfree(argv);
751 	if (r)
752 		goto bad;
753 
754 	t->highs[t->num_targets++] = tgt->begin + tgt->len - 1;
755 
756 	if (!tgt->num_discard_bios && tgt->discards_supported)
757 		DMWARN("%s: %s: ignoring discards_supported because num_discard_bios is zero.",
758 		       dm_device_name(t->md), type);
759 
760 	return 0;
761 
762  bad:
763 	DMERR("%s: %s: %s", dm_device_name(t->md), type, tgt->error);
764 	dm_put_target_type(tgt->type);
765 	return r;
766 }
767 
768 /*
769  * Target argument parsing helpers.
770  */
771 static int validate_next_arg(struct dm_arg *arg, struct dm_arg_set *arg_set,
772 			     unsigned *value, char **error, unsigned grouped)
773 {
774 	const char *arg_str = dm_shift_arg(arg_set);
775 	char dummy;
776 
777 	if (!arg_str ||
778 	    (sscanf(arg_str, "%u%c", value, &dummy) != 1) ||
779 	    (*value < arg->min) ||
780 	    (*value > arg->max) ||
781 	    (grouped && arg_set->argc < *value)) {
782 		*error = arg->error;
783 		return -EINVAL;
784 	}
785 
786 	return 0;
787 }
788 
789 int dm_read_arg(struct dm_arg *arg, struct dm_arg_set *arg_set,
790 		unsigned *value, char **error)
791 {
792 	return validate_next_arg(arg, arg_set, value, error, 0);
793 }
794 EXPORT_SYMBOL(dm_read_arg);
795 
796 int dm_read_arg_group(struct dm_arg *arg, struct dm_arg_set *arg_set,
797 		      unsigned *value, char **error)
798 {
799 	return validate_next_arg(arg, arg_set, value, error, 1);
800 }
801 EXPORT_SYMBOL(dm_read_arg_group);
802 
803 const char *dm_shift_arg(struct dm_arg_set *as)
804 {
805 	char *r;
806 
807 	if (as->argc) {
808 		as->argc--;
809 		r = *as->argv;
810 		as->argv++;
811 		return r;
812 	}
813 
814 	return NULL;
815 }
816 EXPORT_SYMBOL(dm_shift_arg);
817 
818 void dm_consume_args(struct dm_arg_set *as, unsigned num_args)
819 {
820 	BUG_ON(as->argc < num_args);
821 	as->argc -= num_args;
822 	as->argv += num_args;
823 }
824 EXPORT_SYMBOL(dm_consume_args);
825 
826 static int dm_table_set_type(struct dm_table *t)
827 {
828 	unsigned i;
829 	unsigned bio_based = 0, request_based = 0, hybrid = 0;
830 	struct dm_target *tgt;
831 	struct dm_dev_internal *dd;
832 	struct list_head *devices;
833 	unsigned live_md_type;
834 
835 	for (i = 0; i < t->num_targets; i++) {
836 		tgt = t->targets + i;
837 		if (dm_target_hybrid(tgt))
838 			hybrid = 1;
839 		else if (dm_target_request_based(tgt))
840 			request_based = 1;
841 		else
842 			bio_based = 1;
843 
844 		if (bio_based && request_based) {
845 			DMWARN("Inconsistent table: different target types"
846 			       " can't be mixed up");
847 			return -EINVAL;
848 		}
849 	}
850 
851 	if (hybrid && !bio_based && !request_based) {
852 		/*
853 		 * The targets can work either way.
854 		 * Determine the type from the live device.
855 		 * Default to bio-based if device is new.
856 		 */
857 		live_md_type = dm_get_md_type(t->md);
858 		if (live_md_type == DM_TYPE_REQUEST_BASED)
859 			request_based = 1;
860 		else
861 			bio_based = 1;
862 	}
863 
864 	if (bio_based) {
865 		/* We must use this table as bio-based */
866 		t->type = DM_TYPE_BIO_BASED;
867 		return 0;
868 	}
869 
870 	BUG_ON(!request_based); /* No targets in this table */
871 
872 	/* Non-request-stackable devices can't be used for request-based dm */
873 	devices = dm_table_get_devices(t);
874 	list_for_each_entry(dd, devices, list) {
875 		if (!blk_queue_stackable(bdev_get_queue(dd->dm_dev->bdev))) {
876 			DMWARN("table load rejected: including"
877 			       " non-request-stackable devices");
878 			return -EINVAL;
879 		}
880 	}
881 
882 	/*
883 	 * Request-based dm supports only tables that have a single target now.
884 	 * To support multiple targets, request splitting support is needed,
885 	 * and that needs lots of changes in the block-layer.
886 	 * (e.g. request completion process for partial completion.)
887 	 */
888 	if (t->num_targets > 1) {
889 		DMWARN("Request-based dm doesn't support multiple targets yet");
890 		return -EINVAL;
891 	}
892 
893 	t->type = DM_TYPE_REQUEST_BASED;
894 
895 	return 0;
896 }
897 
898 unsigned dm_table_get_type(struct dm_table *t)
899 {
900 	return t->type;
901 }
902 
903 struct target_type *dm_table_get_immutable_target_type(struct dm_table *t)
904 {
905 	return t->immutable_target_type;
906 }
907 
908 bool dm_table_request_based(struct dm_table *t)
909 {
910 	return dm_table_get_type(t) == DM_TYPE_REQUEST_BASED;
911 }
912 
913 static int dm_table_alloc_md_mempools(struct dm_table *t)
914 {
915 	unsigned type = dm_table_get_type(t);
916 	unsigned per_bio_data_size = 0;
917 	struct dm_target *tgt;
918 	unsigned i;
919 
920 	if (unlikely(type == DM_TYPE_NONE)) {
921 		DMWARN("no table type is set, can't allocate mempools");
922 		return -EINVAL;
923 	}
924 
925 	if (type == DM_TYPE_BIO_BASED)
926 		for (i = 0; i < t->num_targets; i++) {
927 			tgt = t->targets + i;
928 			per_bio_data_size = max(per_bio_data_size, tgt->per_bio_data_size);
929 		}
930 
931 	t->mempools = dm_alloc_md_mempools(type, t->integrity_supported, per_bio_data_size);
932 	if (!t->mempools)
933 		return -ENOMEM;
934 
935 	return 0;
936 }
937 
938 void dm_table_free_md_mempools(struct dm_table *t)
939 {
940 	dm_free_md_mempools(t->mempools);
941 	t->mempools = NULL;
942 }
943 
944 struct dm_md_mempools *dm_table_get_md_mempools(struct dm_table *t)
945 {
946 	return t->mempools;
947 }
948 
949 static int setup_indexes(struct dm_table *t)
950 {
951 	int i;
952 	unsigned int total = 0;
953 	sector_t *indexes;
954 
955 	/* allocate the space for *all* the indexes */
956 	for (i = t->depth - 2; i >= 0; i--) {
957 		t->counts[i] = dm_div_up(t->counts[i + 1], CHILDREN_PER_NODE);
958 		total += t->counts[i];
959 	}
960 
961 	indexes = (sector_t *) dm_vcalloc(total, (unsigned long) NODE_SIZE);
962 	if (!indexes)
963 		return -ENOMEM;
964 
965 	/* set up internal nodes, bottom-up */
966 	for (i = t->depth - 2; i >= 0; i--) {
967 		t->index[i] = indexes;
968 		indexes += (KEYS_PER_NODE * t->counts[i]);
969 		setup_btree_index(i, t);
970 	}
971 
972 	return 0;
973 }
974 
975 /*
976  * Builds the btree to index the map.
977  */
978 static int dm_table_build_index(struct dm_table *t)
979 {
980 	int r = 0;
981 	unsigned int leaf_nodes;
982 
983 	/* how many indexes will the btree have ? */
984 	leaf_nodes = dm_div_up(t->num_targets, KEYS_PER_NODE);
985 	t->depth = 1 + int_log(leaf_nodes, CHILDREN_PER_NODE);
986 
987 	/* leaf layer has already been set up */
988 	t->counts[t->depth - 1] = leaf_nodes;
989 	t->index[t->depth - 1] = t->highs;
990 
991 	if (t->depth >= 2)
992 		r = setup_indexes(t);
993 
994 	return r;
995 }
996 
997 /*
998  * Get a disk whose integrity profile reflects the table's profile.
999  * If %match_all is true, all devices' profiles must match.
1000  * If %match_all is false, all devices must at least have an
1001  * allocated integrity profile; but uninitialized is ok.
1002  * Returns NULL if integrity support was inconsistent or unavailable.
1003  */
1004 static struct gendisk * dm_table_get_integrity_disk(struct dm_table *t,
1005 						    bool match_all)
1006 {
1007 	struct list_head *devices = dm_table_get_devices(t);
1008 	struct dm_dev_internal *dd = NULL;
1009 	struct gendisk *prev_disk = NULL, *template_disk = NULL;
1010 
1011 	list_for_each_entry(dd, devices, list) {
1012 		template_disk = dd->dm_dev->bdev->bd_disk;
1013 		if (!blk_get_integrity(template_disk))
1014 			goto no_integrity;
1015 		if (!match_all && !blk_integrity_is_initialized(template_disk))
1016 			continue; /* skip uninitialized profiles */
1017 		else if (prev_disk &&
1018 			 blk_integrity_compare(prev_disk, template_disk) < 0)
1019 			goto no_integrity;
1020 		prev_disk = template_disk;
1021 	}
1022 
1023 	return template_disk;
1024 
1025 no_integrity:
1026 	if (prev_disk)
1027 		DMWARN("%s: integrity not set: %s and %s profile mismatch",
1028 		       dm_device_name(t->md),
1029 		       prev_disk->disk_name,
1030 		       template_disk->disk_name);
1031 	return NULL;
1032 }
1033 
1034 /*
1035  * Register the mapped device for blk_integrity support if
1036  * the underlying devices have an integrity profile.  But all devices
1037  * may not have matching profiles (checking all devices isn't reliable
1038  * during table load because this table may use other DM device(s) which
1039  * must be resumed before they will have an initialized integity profile).
1040  * Stacked DM devices force a 2 stage integrity profile validation:
1041  * 1 - during load, validate all initialized integrity profiles match
1042  * 2 - during resume, validate all integrity profiles match
1043  */
1044 static int dm_table_prealloc_integrity(struct dm_table *t, struct mapped_device *md)
1045 {
1046 	struct gendisk *template_disk = NULL;
1047 
1048 	template_disk = dm_table_get_integrity_disk(t, false);
1049 	if (!template_disk)
1050 		return 0;
1051 
1052 	if (!blk_integrity_is_initialized(dm_disk(md))) {
1053 		t->integrity_supported = 1;
1054 		return blk_integrity_register(dm_disk(md), NULL);
1055 	}
1056 
1057 	/*
1058 	 * If DM device already has an initalized integrity
1059 	 * profile the new profile should not conflict.
1060 	 */
1061 	if (blk_integrity_is_initialized(template_disk) &&
1062 	    blk_integrity_compare(dm_disk(md), template_disk) < 0) {
1063 		DMWARN("%s: conflict with existing integrity profile: "
1064 		       "%s profile mismatch",
1065 		       dm_device_name(t->md),
1066 		       template_disk->disk_name);
1067 		return 1;
1068 	}
1069 
1070 	/* Preserve existing initialized integrity profile */
1071 	t->integrity_supported = 1;
1072 	return 0;
1073 }
1074 
1075 /*
1076  * Prepares the table for use by building the indices,
1077  * setting the type, and allocating mempools.
1078  */
1079 int dm_table_complete(struct dm_table *t)
1080 {
1081 	int r;
1082 
1083 	r = dm_table_set_type(t);
1084 	if (r) {
1085 		DMERR("unable to set table type");
1086 		return r;
1087 	}
1088 
1089 	r = dm_table_build_index(t);
1090 	if (r) {
1091 		DMERR("unable to build btrees");
1092 		return r;
1093 	}
1094 
1095 	r = dm_table_prealloc_integrity(t, t->md);
1096 	if (r) {
1097 		DMERR("could not register integrity profile.");
1098 		return r;
1099 	}
1100 
1101 	r = dm_table_alloc_md_mempools(t);
1102 	if (r)
1103 		DMERR("unable to allocate mempools");
1104 
1105 	return r;
1106 }
1107 
1108 static DEFINE_MUTEX(_event_lock);
1109 void dm_table_event_callback(struct dm_table *t,
1110 			     void (*fn)(void *), void *context)
1111 {
1112 	mutex_lock(&_event_lock);
1113 	t->event_fn = fn;
1114 	t->event_context = context;
1115 	mutex_unlock(&_event_lock);
1116 }
1117 
1118 void dm_table_event(struct dm_table *t)
1119 {
1120 	/*
1121 	 * You can no longer call dm_table_event() from interrupt
1122 	 * context, use a bottom half instead.
1123 	 */
1124 	BUG_ON(in_interrupt());
1125 
1126 	mutex_lock(&_event_lock);
1127 	if (t->event_fn)
1128 		t->event_fn(t->event_context);
1129 	mutex_unlock(&_event_lock);
1130 }
1131 EXPORT_SYMBOL(dm_table_event);
1132 
1133 sector_t dm_table_get_size(struct dm_table *t)
1134 {
1135 	return t->num_targets ? (t->highs[t->num_targets - 1] + 1) : 0;
1136 }
1137 EXPORT_SYMBOL(dm_table_get_size);
1138 
1139 struct dm_target *dm_table_get_target(struct dm_table *t, unsigned int index)
1140 {
1141 	if (index >= t->num_targets)
1142 		return NULL;
1143 
1144 	return t->targets + index;
1145 }
1146 
1147 /*
1148  * Search the btree for the correct target.
1149  *
1150  * Caller should check returned pointer with dm_target_is_valid()
1151  * to trap I/O beyond end of device.
1152  */
1153 struct dm_target *dm_table_find_target(struct dm_table *t, sector_t sector)
1154 {
1155 	unsigned int l, n = 0, k = 0;
1156 	sector_t *node;
1157 
1158 	for (l = 0; l < t->depth; l++) {
1159 		n = get_child(n, k);
1160 		node = get_node(t, l, n);
1161 
1162 		for (k = 0; k < KEYS_PER_NODE; k++)
1163 			if (node[k] >= sector)
1164 				break;
1165 	}
1166 
1167 	return &t->targets[(KEYS_PER_NODE * n) + k];
1168 }
1169 
1170 static int count_device(struct dm_target *ti, struct dm_dev *dev,
1171 			sector_t start, sector_t len, void *data)
1172 {
1173 	unsigned *num_devices = data;
1174 
1175 	(*num_devices)++;
1176 
1177 	return 0;
1178 }
1179 
1180 /*
1181  * Check whether a table has no data devices attached using each
1182  * target's iterate_devices method.
1183  * Returns false if the result is unknown because a target doesn't
1184  * support iterate_devices.
1185  */
1186 bool dm_table_has_no_data_devices(struct dm_table *table)
1187 {
1188 	struct dm_target *uninitialized_var(ti);
1189 	unsigned i = 0, num_devices = 0;
1190 
1191 	while (i < dm_table_get_num_targets(table)) {
1192 		ti = dm_table_get_target(table, i++);
1193 
1194 		if (!ti->type->iterate_devices)
1195 			return false;
1196 
1197 		ti->type->iterate_devices(ti, count_device, &num_devices);
1198 		if (num_devices)
1199 			return false;
1200 	}
1201 
1202 	return true;
1203 }
1204 
1205 /*
1206  * Establish the new table's queue_limits and validate them.
1207  */
1208 int dm_calculate_queue_limits(struct dm_table *table,
1209 			      struct queue_limits *limits)
1210 {
1211 	struct dm_target *uninitialized_var(ti);
1212 	struct queue_limits ti_limits;
1213 	unsigned i = 0;
1214 
1215 	blk_set_stacking_limits(limits);
1216 
1217 	while (i < dm_table_get_num_targets(table)) {
1218 		blk_set_stacking_limits(&ti_limits);
1219 
1220 		ti = dm_table_get_target(table, i++);
1221 
1222 		if (!ti->type->iterate_devices)
1223 			goto combine_limits;
1224 
1225 		/*
1226 		 * Combine queue limits of all the devices this target uses.
1227 		 */
1228 		ti->type->iterate_devices(ti, dm_set_device_limits,
1229 					  &ti_limits);
1230 
1231 		/* Set I/O hints portion of queue limits */
1232 		if (ti->type->io_hints)
1233 			ti->type->io_hints(ti, &ti_limits);
1234 
1235 		/*
1236 		 * Check each device area is consistent with the target's
1237 		 * overall queue limits.
1238 		 */
1239 		if (ti->type->iterate_devices(ti, device_area_is_invalid,
1240 					      &ti_limits))
1241 			return -EINVAL;
1242 
1243 combine_limits:
1244 		/*
1245 		 * Merge this target's queue limits into the overall limits
1246 		 * for the table.
1247 		 */
1248 		if (blk_stack_limits(limits, &ti_limits, 0) < 0)
1249 			DMWARN("%s: adding target device "
1250 			       "(start sect %llu len %llu) "
1251 			       "caused an alignment inconsistency",
1252 			       dm_device_name(table->md),
1253 			       (unsigned long long) ti->begin,
1254 			       (unsigned long long) ti->len);
1255 	}
1256 
1257 	return validate_hardware_logical_block_alignment(table, limits);
1258 }
1259 
1260 /*
1261  * Set the integrity profile for this device if all devices used have
1262  * matching profiles.  We're quite deep in the resume path but still
1263  * don't know if all devices (particularly DM devices this device
1264  * may be stacked on) have matching profiles.  Even if the profiles
1265  * don't match we have no way to fail (to resume) at this point.
1266  */
1267 static void dm_table_set_integrity(struct dm_table *t)
1268 {
1269 	struct gendisk *template_disk = NULL;
1270 
1271 	if (!blk_get_integrity(dm_disk(t->md)))
1272 		return;
1273 
1274 	template_disk = dm_table_get_integrity_disk(t, true);
1275 	if (template_disk)
1276 		blk_integrity_register(dm_disk(t->md),
1277 				       blk_get_integrity(template_disk));
1278 	else if (blk_integrity_is_initialized(dm_disk(t->md)))
1279 		DMWARN("%s: device no longer has a valid integrity profile",
1280 		       dm_device_name(t->md));
1281 	else
1282 		DMWARN("%s: unable to establish an integrity profile",
1283 		       dm_device_name(t->md));
1284 }
1285 
1286 static int device_flush_capable(struct dm_target *ti, struct dm_dev *dev,
1287 				sector_t start, sector_t len, void *data)
1288 {
1289 	unsigned flush = (*(unsigned *)data);
1290 	struct request_queue *q = bdev_get_queue(dev->bdev);
1291 
1292 	return q && (q->flush_flags & flush);
1293 }
1294 
1295 static bool dm_table_supports_flush(struct dm_table *t, unsigned flush)
1296 {
1297 	struct dm_target *ti;
1298 	unsigned i = 0;
1299 
1300 	/*
1301 	 * Require at least one underlying device to support flushes.
1302 	 * t->devices includes internal dm devices such as mirror logs
1303 	 * so we need to use iterate_devices here, which targets
1304 	 * supporting flushes must provide.
1305 	 */
1306 	while (i < dm_table_get_num_targets(t)) {
1307 		ti = dm_table_get_target(t, i++);
1308 
1309 		if (!ti->num_flush_bios)
1310 			continue;
1311 
1312 		if (ti->flush_supported)
1313 			return 1;
1314 
1315 		if (ti->type->iterate_devices &&
1316 		    ti->type->iterate_devices(ti, device_flush_capable, &flush))
1317 			return 1;
1318 	}
1319 
1320 	return 0;
1321 }
1322 
1323 static bool dm_table_discard_zeroes_data(struct dm_table *t)
1324 {
1325 	struct dm_target *ti;
1326 	unsigned i = 0;
1327 
1328 	/* Ensure that all targets supports discard_zeroes_data. */
1329 	while (i < dm_table_get_num_targets(t)) {
1330 		ti = dm_table_get_target(t, i++);
1331 
1332 		if (ti->discard_zeroes_data_unsupported)
1333 			return 0;
1334 	}
1335 
1336 	return 1;
1337 }
1338 
1339 static int device_is_nonrot(struct dm_target *ti, struct dm_dev *dev,
1340 			    sector_t start, sector_t len, void *data)
1341 {
1342 	struct request_queue *q = bdev_get_queue(dev->bdev);
1343 
1344 	return q && blk_queue_nonrot(q);
1345 }
1346 
1347 static int device_is_not_random(struct dm_target *ti, struct dm_dev *dev,
1348 			     sector_t start, sector_t len, void *data)
1349 {
1350 	struct request_queue *q = bdev_get_queue(dev->bdev);
1351 
1352 	return q && !blk_queue_add_random(q);
1353 }
1354 
1355 static int queue_supports_sg_merge(struct dm_target *ti, struct dm_dev *dev,
1356 				   sector_t start, sector_t len, void *data)
1357 {
1358 	struct request_queue *q = bdev_get_queue(dev->bdev);
1359 
1360 	return q && !test_bit(QUEUE_FLAG_NO_SG_MERGE, &q->queue_flags);
1361 }
1362 
1363 static bool dm_table_all_devices_attribute(struct dm_table *t,
1364 					   iterate_devices_callout_fn func)
1365 {
1366 	struct dm_target *ti;
1367 	unsigned i = 0;
1368 
1369 	while (i < dm_table_get_num_targets(t)) {
1370 		ti = dm_table_get_target(t, i++);
1371 
1372 		if (!ti->type->iterate_devices ||
1373 		    !ti->type->iterate_devices(ti, func, NULL))
1374 			return 0;
1375 	}
1376 
1377 	return 1;
1378 }
1379 
1380 static int device_not_write_same_capable(struct dm_target *ti, struct dm_dev *dev,
1381 					 sector_t start, sector_t len, void *data)
1382 {
1383 	struct request_queue *q = bdev_get_queue(dev->bdev);
1384 
1385 	return q && !q->limits.max_write_same_sectors;
1386 }
1387 
1388 static bool dm_table_supports_write_same(struct dm_table *t)
1389 {
1390 	struct dm_target *ti;
1391 	unsigned i = 0;
1392 
1393 	while (i < dm_table_get_num_targets(t)) {
1394 		ti = dm_table_get_target(t, i++);
1395 
1396 		if (!ti->num_write_same_bios)
1397 			return false;
1398 
1399 		if (!ti->type->iterate_devices ||
1400 		    ti->type->iterate_devices(ti, device_not_write_same_capable, NULL))
1401 			return false;
1402 	}
1403 
1404 	return true;
1405 }
1406 
1407 static int device_discard_capable(struct dm_target *ti, struct dm_dev *dev,
1408 				  sector_t start, sector_t len, void *data)
1409 {
1410 	struct request_queue *q = bdev_get_queue(dev->bdev);
1411 
1412 	return q && blk_queue_discard(q);
1413 }
1414 
1415 static bool dm_table_supports_discards(struct dm_table *t)
1416 {
1417 	struct dm_target *ti;
1418 	unsigned i = 0;
1419 
1420 	/*
1421 	 * Unless any target used by the table set discards_supported,
1422 	 * require at least one underlying device to support discards.
1423 	 * t->devices includes internal dm devices such as mirror logs
1424 	 * so we need to use iterate_devices here, which targets
1425 	 * supporting discard selectively must provide.
1426 	 */
1427 	while (i < dm_table_get_num_targets(t)) {
1428 		ti = dm_table_get_target(t, i++);
1429 
1430 		if (!ti->num_discard_bios)
1431 			continue;
1432 
1433 		if (ti->discards_supported)
1434 			return 1;
1435 
1436 		if (ti->type->iterate_devices &&
1437 		    ti->type->iterate_devices(ti, device_discard_capable, NULL))
1438 			return 1;
1439 	}
1440 
1441 	return 0;
1442 }
1443 
1444 void dm_table_set_restrictions(struct dm_table *t, struct request_queue *q,
1445 			       struct queue_limits *limits)
1446 {
1447 	unsigned flush = 0;
1448 
1449 	/*
1450 	 * Copy table's limits to the DM device's request_queue
1451 	 */
1452 	q->limits = *limits;
1453 
1454 	if (!dm_table_supports_discards(t))
1455 		queue_flag_clear_unlocked(QUEUE_FLAG_DISCARD, q);
1456 	else
1457 		queue_flag_set_unlocked(QUEUE_FLAG_DISCARD, q);
1458 
1459 	if (dm_table_supports_flush(t, REQ_FLUSH)) {
1460 		flush |= REQ_FLUSH;
1461 		if (dm_table_supports_flush(t, REQ_FUA))
1462 			flush |= REQ_FUA;
1463 	}
1464 	blk_queue_flush(q, flush);
1465 
1466 	if (!dm_table_discard_zeroes_data(t))
1467 		q->limits.discard_zeroes_data = 0;
1468 
1469 	/* Ensure that all underlying devices are non-rotational. */
1470 	if (dm_table_all_devices_attribute(t, device_is_nonrot))
1471 		queue_flag_set_unlocked(QUEUE_FLAG_NONROT, q);
1472 	else
1473 		queue_flag_clear_unlocked(QUEUE_FLAG_NONROT, q);
1474 
1475 	if (!dm_table_supports_write_same(t))
1476 		q->limits.max_write_same_sectors = 0;
1477 
1478 	if (dm_table_all_devices_attribute(t, queue_supports_sg_merge))
1479 		queue_flag_clear_unlocked(QUEUE_FLAG_NO_SG_MERGE, q);
1480 	else
1481 		queue_flag_set_unlocked(QUEUE_FLAG_NO_SG_MERGE, q);
1482 
1483 	dm_table_set_integrity(t);
1484 
1485 	/*
1486 	 * Determine whether or not this queue's I/O timings contribute
1487 	 * to the entropy pool, Only request-based targets use this.
1488 	 * Clear QUEUE_FLAG_ADD_RANDOM if any underlying device does not
1489 	 * have it set.
1490 	 */
1491 	if (blk_queue_add_random(q) && dm_table_all_devices_attribute(t, device_is_not_random))
1492 		queue_flag_clear_unlocked(QUEUE_FLAG_ADD_RANDOM, q);
1493 
1494 	/*
1495 	 * QUEUE_FLAG_STACKABLE must be set after all queue settings are
1496 	 * visible to other CPUs because, once the flag is set, incoming bios
1497 	 * are processed by request-based dm, which refers to the queue
1498 	 * settings.
1499 	 * Until the flag set, bios are passed to bio-based dm and queued to
1500 	 * md->deferred where queue settings are not needed yet.
1501 	 * Those bios are passed to request-based dm at the resume time.
1502 	 */
1503 	smp_mb();
1504 	if (dm_table_request_based(t))
1505 		queue_flag_set_unlocked(QUEUE_FLAG_STACKABLE, q);
1506 }
1507 
1508 unsigned int dm_table_get_num_targets(struct dm_table *t)
1509 {
1510 	return t->num_targets;
1511 }
1512 
1513 struct list_head *dm_table_get_devices(struct dm_table *t)
1514 {
1515 	return &t->devices;
1516 }
1517 
1518 fmode_t dm_table_get_mode(struct dm_table *t)
1519 {
1520 	return t->mode;
1521 }
1522 EXPORT_SYMBOL(dm_table_get_mode);
1523 
1524 static void suspend_targets(struct dm_table *t, unsigned postsuspend)
1525 {
1526 	int i = t->num_targets;
1527 	struct dm_target *ti = t->targets;
1528 
1529 	while (i--) {
1530 		if (postsuspend) {
1531 			if (ti->type->postsuspend)
1532 				ti->type->postsuspend(ti);
1533 		} else if (ti->type->presuspend)
1534 			ti->type->presuspend(ti);
1535 
1536 		ti++;
1537 	}
1538 }
1539 
1540 void dm_table_presuspend_targets(struct dm_table *t)
1541 {
1542 	if (!t)
1543 		return;
1544 
1545 	suspend_targets(t, 0);
1546 }
1547 
1548 void dm_table_postsuspend_targets(struct dm_table *t)
1549 {
1550 	if (!t)
1551 		return;
1552 
1553 	suspend_targets(t, 1);
1554 }
1555 
1556 int dm_table_resume_targets(struct dm_table *t)
1557 {
1558 	int i, r = 0;
1559 
1560 	for (i = 0; i < t->num_targets; i++) {
1561 		struct dm_target *ti = t->targets + i;
1562 
1563 		if (!ti->type->preresume)
1564 			continue;
1565 
1566 		r = ti->type->preresume(ti);
1567 		if (r) {
1568 			DMERR("%s: %s: preresume failed, error = %d",
1569 			      dm_device_name(t->md), ti->type->name, r);
1570 			return r;
1571 		}
1572 	}
1573 
1574 	for (i = 0; i < t->num_targets; i++) {
1575 		struct dm_target *ti = t->targets + i;
1576 
1577 		if (ti->type->resume)
1578 			ti->type->resume(ti);
1579 	}
1580 
1581 	return 0;
1582 }
1583 
1584 void dm_table_add_target_callbacks(struct dm_table *t, struct dm_target_callbacks *cb)
1585 {
1586 	list_add(&cb->list, &t->target_callbacks);
1587 }
1588 EXPORT_SYMBOL_GPL(dm_table_add_target_callbacks);
1589 
1590 int dm_table_any_congested(struct dm_table *t, int bdi_bits)
1591 {
1592 	struct dm_dev_internal *dd;
1593 	struct list_head *devices = dm_table_get_devices(t);
1594 	struct dm_target_callbacks *cb;
1595 	int r = 0;
1596 
1597 	list_for_each_entry(dd, devices, list) {
1598 		struct request_queue *q = bdev_get_queue(dd->dm_dev->bdev);
1599 		char b[BDEVNAME_SIZE];
1600 
1601 		if (likely(q))
1602 			r |= bdi_congested(&q->backing_dev_info, bdi_bits);
1603 		else
1604 			DMWARN_LIMIT("%s: any_congested: nonexistent device %s",
1605 				     dm_device_name(t->md),
1606 				     bdevname(dd->dm_dev->bdev, b));
1607 	}
1608 
1609 	list_for_each_entry(cb, &t->target_callbacks, list)
1610 		if (cb->congested_fn)
1611 			r |= cb->congested_fn(cb, bdi_bits);
1612 
1613 	return r;
1614 }
1615 
1616 int dm_table_any_busy_target(struct dm_table *t)
1617 {
1618 	unsigned i;
1619 	struct dm_target *ti;
1620 
1621 	for (i = 0; i < t->num_targets; i++) {
1622 		ti = t->targets + i;
1623 		if (ti->type->busy && ti->type->busy(ti))
1624 			return 1;
1625 	}
1626 
1627 	return 0;
1628 }
1629 
1630 struct mapped_device *dm_table_get_md(struct dm_table *t)
1631 {
1632 	return t->md;
1633 }
1634 EXPORT_SYMBOL(dm_table_get_md);
1635 
1636 void dm_table_run_md_queue_async(struct dm_table *t)
1637 {
1638 	struct mapped_device *md;
1639 	struct request_queue *queue;
1640 	unsigned long flags;
1641 
1642 	if (!dm_table_request_based(t))
1643 		return;
1644 
1645 	md = dm_table_get_md(t);
1646 	queue = dm_get_md_queue(md);
1647 	if (queue) {
1648 		spin_lock_irqsave(queue->queue_lock, flags);
1649 		blk_run_queue_async(queue);
1650 		spin_unlock_irqrestore(queue->queue_lock, flags);
1651 	}
1652 }
1653 EXPORT_SYMBOL(dm_table_run_md_queue_async);
1654 
1655