GNU Linux-libre 4.9.308-gnu1
[releases.git] / drivers / md / dm-table.c
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-core.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 #include <linux/blk-mq.h>
22 #include <linux/mount.h>
23
24 #define DM_MSG_PREFIX "table"
25
26 #define MAX_DEPTH 16
27 #define NODE_SIZE L1_CACHE_BYTES
28 #define KEYS_PER_NODE (NODE_SIZE / sizeof(sector_t))
29 #define CHILDREN_PER_NODE (KEYS_PER_NODE + 1)
30
31 struct dm_table {
32         struct mapped_device *md;
33         unsigned type;
34
35         /* btree table */
36         unsigned int depth;
37         unsigned int counts[MAX_DEPTH]; /* in nodes */
38         sector_t *index[MAX_DEPTH];
39
40         unsigned int num_targets;
41         unsigned int num_allocated;
42         sector_t *highs;
43         struct dm_target *targets;
44
45         struct target_type *immutable_target_type;
46
47         bool integrity_supported:1;
48         bool singleton:1;
49         bool all_blk_mq:1;
50
51         /*
52          * Indicates the rw permissions for the new logical
53          * device.  This should be a combination of FMODE_READ
54          * and FMODE_WRITE.
55          */
56         fmode_t mode;
57
58         /* a list of devices used by this table */
59         struct list_head devices;
60
61         /* events get handed up using this callback */
62         void (*event_fn)(void *);
63         void *event_context;
64
65         struct dm_md_mempools *mempools;
66
67         struct list_head target_callbacks;
68 };
69
70 /*
71  * Similar to ceiling(log_size(n))
72  */
73 static unsigned int int_log(unsigned int n, unsigned int base)
74 {
75         int result = 0;
76
77         while (n > 1) {
78                 n = dm_div_up(n, base);
79                 result++;
80         }
81
82         return result;
83 }
84
85 /*
86  * Calculate the index of the child node of the n'th node k'th key.
87  */
88 static inline unsigned int get_child(unsigned int n, unsigned int k)
89 {
90         return (n * CHILDREN_PER_NODE) + k;
91 }
92
93 /*
94  * Return the n'th node of level l from table t.
95  */
96 static inline sector_t *get_node(struct dm_table *t,
97                                  unsigned int l, unsigned int n)
98 {
99         return t->index[l] + (n * KEYS_PER_NODE);
100 }
101
102 /*
103  * Return the highest key that you could lookup from the n'th
104  * node on level l of the btree.
105  */
106 static sector_t high(struct dm_table *t, unsigned int l, unsigned int n)
107 {
108         for (; l < t->depth - 1; l++)
109                 n = get_child(n, CHILDREN_PER_NODE - 1);
110
111         if (n >= t->counts[l])
112                 return (sector_t) - 1;
113
114         return get_node(t, l, n)[KEYS_PER_NODE - 1];
115 }
116
117 /*
118  * Fills in a level of the btree based on the highs of the level
119  * below it.
120  */
121 static int setup_btree_index(unsigned int l, struct dm_table *t)
122 {
123         unsigned int n, k;
124         sector_t *node;
125
126         for (n = 0U; n < t->counts[l]; n++) {
127                 node = get_node(t, l, n);
128
129                 for (k = 0U; k < KEYS_PER_NODE; k++)
130                         node[k] = high(t, l + 1, get_child(n, k));
131         }
132
133         return 0;
134 }
135
136 void *dm_vcalloc(unsigned long nmemb, unsigned long elem_size)
137 {
138         unsigned long size;
139         void *addr;
140
141         /*
142          * Check that we're not going to overflow.
143          */
144         if (nmemb > (ULONG_MAX / elem_size))
145                 return NULL;
146
147         size = nmemb * elem_size;
148         addr = vzalloc(size);
149
150         return addr;
151 }
152 EXPORT_SYMBOL(dm_vcalloc);
153
154 /*
155  * highs, and targets are managed as dynamic arrays during a
156  * table load.
157  */
158 static int alloc_targets(struct dm_table *t, unsigned int num)
159 {
160         sector_t *n_highs;
161         struct dm_target *n_targets;
162
163         /*
164          * Allocate both the target array and offset array at once.
165          * Append an empty entry to catch sectors beyond the end of
166          * the device.
167          */
168         n_highs = (sector_t *) dm_vcalloc(num + 1, sizeof(struct dm_target) +
169                                           sizeof(sector_t));
170         if (!n_highs)
171                 return -ENOMEM;
172
173         n_targets = (struct dm_target *) (n_highs + num);
174
175         memset(n_highs, -1, sizeof(*n_highs) * num);
176         vfree(t->highs);
177
178         t->num_allocated = num;
179         t->highs = n_highs;
180         t->targets = n_targets;
181
182         return 0;
183 }
184
185 int dm_table_create(struct dm_table **result, fmode_t mode,
186                     unsigned num_targets, struct mapped_device *md)
187 {
188         struct dm_table *t = kzalloc(sizeof(*t), GFP_KERNEL);
189
190         if (!t)
191                 return -ENOMEM;
192
193         INIT_LIST_HEAD(&t->devices);
194         INIT_LIST_HEAD(&t->target_callbacks);
195
196         if (!num_targets)
197                 num_targets = KEYS_PER_NODE;
198
199         num_targets = dm_round_up(num_targets, KEYS_PER_NODE);
200
201         if (!num_targets) {
202                 kfree(t);
203                 return -ENOMEM;
204         }
205
206         if (alloc_targets(t, num_targets)) {
207                 kfree(t);
208                 return -ENOMEM;
209         }
210
211         t->type = DM_TYPE_NONE;
212         t->mode = mode;
213         t->md = md;
214         *result = t;
215         return 0;
216 }
217
218 static void free_devices(struct list_head *devices, struct mapped_device *md)
219 {
220         struct list_head *tmp, *next;
221
222         list_for_each_safe(tmp, next, devices) {
223                 struct dm_dev_internal *dd =
224                     list_entry(tmp, struct dm_dev_internal, list);
225                 DMWARN("%s: dm_table_destroy: dm_put_device call missing for %s",
226                        dm_device_name(md), dd->dm_dev->name);
227                 dm_put_table_device(md, dd->dm_dev);
228                 kfree(dd);
229         }
230 }
231
232 void dm_table_destroy(struct dm_table *t)
233 {
234         unsigned int i;
235
236         if (!t)
237                 return;
238
239         /* free the indexes */
240         if (t->depth >= 2)
241                 vfree(t->index[t->depth - 2]);
242
243         /* free the targets */
244         for (i = 0; i < t->num_targets; i++) {
245                 struct dm_target *tgt = t->targets + i;
246
247                 if (tgt->type->dtr)
248                         tgt->type->dtr(tgt);
249
250                 dm_put_target_type(tgt->type);
251         }
252
253         vfree(t->highs);
254
255         /* free the device list */
256         free_devices(&t->devices, t->md);
257
258         dm_free_md_mempools(t->mempools);
259
260         kfree(t);
261 }
262
263 /*
264  * See if we've already got a device in the list.
265  */
266 static struct dm_dev_internal *find_device(struct list_head *l, dev_t dev)
267 {
268         struct dm_dev_internal *dd;
269
270         list_for_each_entry (dd, l, list)
271                 if (dd->dm_dev->bdev->bd_dev == dev)
272                         return dd;
273
274         return NULL;
275 }
276
277 /*
278  * If possible, this checks an area of a destination device is invalid.
279  */
280 static int device_area_is_invalid(struct dm_target *ti, struct dm_dev *dev,
281                                   sector_t start, sector_t len, void *data)
282 {
283         struct request_queue *q;
284         struct queue_limits *limits = data;
285         struct block_device *bdev = dev->bdev;
286         sector_t dev_size =
287                 i_size_read(bdev->bd_inode) >> SECTOR_SHIFT;
288         unsigned short logical_block_size_sectors =
289                 limits->logical_block_size >> SECTOR_SHIFT;
290         char b[BDEVNAME_SIZE];
291
292         /*
293          * Some devices exist without request functions,
294          * such as loop devices not yet bound to backing files.
295          * Forbid the use of such devices.
296          */
297         q = bdev_get_queue(bdev);
298         if (!q || !q->make_request_fn) {
299                 DMWARN("%s: %s is not yet initialised: "
300                        "start=%llu, len=%llu, dev_size=%llu",
301                        dm_device_name(ti->table->md), bdevname(bdev, b),
302                        (unsigned long long)start,
303                        (unsigned long long)len,
304                        (unsigned long long)dev_size);
305                 return 1;
306         }
307
308         if (!dev_size)
309                 return 0;
310
311         if ((start >= dev_size) || (start + len > dev_size)) {
312                 DMWARN("%s: %s too small for target: "
313                        "start=%llu, len=%llu, dev_size=%llu",
314                        dm_device_name(ti->table->md), bdevname(bdev, b),
315                        (unsigned long long)start,
316                        (unsigned long long)len,
317                        (unsigned long long)dev_size);
318                 return 1;
319         }
320
321         if (logical_block_size_sectors <= 1)
322                 return 0;
323
324         if (start & (logical_block_size_sectors - 1)) {
325                 DMWARN("%s: start=%llu not aligned to h/w "
326                        "logical block size %u of %s",
327                        dm_device_name(ti->table->md),
328                        (unsigned long long)start,
329                        limits->logical_block_size, bdevname(bdev, b));
330                 return 1;
331         }
332
333         if (len & (logical_block_size_sectors - 1)) {
334                 DMWARN("%s: len=%llu not aligned to h/w "
335                        "logical block size %u of %s",
336                        dm_device_name(ti->table->md),
337                        (unsigned long long)len,
338                        limits->logical_block_size, bdevname(bdev, b));
339                 return 1;
340         }
341
342         return 0;
343 }
344
345 /*
346  * This upgrades the mode on an already open dm_dev, being
347  * careful to leave things as they were if we fail to reopen the
348  * device and not to touch the existing bdev field in case
349  * it is accessed concurrently inside dm_table_any_congested().
350  */
351 static int upgrade_mode(struct dm_dev_internal *dd, fmode_t new_mode,
352                         struct mapped_device *md)
353 {
354         int r;
355         struct dm_dev *old_dev, *new_dev;
356
357         old_dev = dd->dm_dev;
358
359         r = dm_get_table_device(md, dd->dm_dev->bdev->bd_dev,
360                                 dd->dm_dev->mode | new_mode, &new_dev);
361         if (r)
362                 return r;
363
364         dd->dm_dev = new_dev;
365         dm_put_table_device(md, old_dev);
366
367         return 0;
368 }
369
370 /*
371  * Convert the path to a device
372  */
373 dev_t dm_get_dev_t(const char *path)
374 {
375         dev_t uninitialized_var(dev);
376         struct block_device *bdev;
377
378         bdev = lookup_bdev(path);
379         if (IS_ERR(bdev))
380                 dev = name_to_dev_t(path);
381         else {
382                 dev = bdev->bd_dev;
383                 bdput(bdev);
384         }
385
386         return dev;
387 }
388 EXPORT_SYMBOL_GPL(dm_get_dev_t);
389
390 /*
391  * Add a device to the list, or just increment the usage count if
392  * it's already present.
393  */
394 int dm_get_device(struct dm_target *ti, const char *path, fmode_t mode,
395                   struct dm_dev **result)
396 {
397         int r;
398         dev_t dev;
399         unsigned int major, minor;
400         char dummy;
401         struct dm_dev_internal *dd;
402         struct dm_table *t = ti->table;
403
404         BUG_ON(!t);
405
406         if (sscanf(path, "%u:%u%c", &major, &minor, &dummy) == 2) {
407                 /* Extract the major/minor numbers */
408                 dev = MKDEV(major, minor);
409                 if (MAJOR(dev) != major || MINOR(dev) != minor)
410                         return -EOVERFLOW;
411         } else {
412                 dev = dm_get_dev_t(path);
413                 if (!dev)
414                         return -ENODEV;
415         }
416
417         dd = find_device(&t->devices, dev);
418         if (!dd) {
419                 dd = kmalloc(sizeof(*dd), GFP_KERNEL);
420                 if (!dd)
421                         return -ENOMEM;
422
423                 if ((r = dm_get_table_device(t->md, dev, mode, &dd->dm_dev))) {
424                         kfree(dd);
425                         return r;
426                 }
427
428                 atomic_set(&dd->count, 0);
429                 list_add(&dd->list, &t->devices);
430
431         } else if (dd->dm_dev->mode != (mode | dd->dm_dev->mode)) {
432                 r = upgrade_mode(dd, mode, t->md);
433                 if (r)
434                         return r;
435         }
436         atomic_inc(&dd->count);
437
438         *result = dd->dm_dev;
439         return 0;
440 }
441 EXPORT_SYMBOL(dm_get_device);
442
443 static int dm_set_device_limits(struct dm_target *ti, struct dm_dev *dev,
444                                 sector_t start, sector_t len, void *data)
445 {
446         struct queue_limits *limits = data;
447         struct block_device *bdev = dev->bdev;
448         struct request_queue *q = bdev_get_queue(bdev);
449         char b[BDEVNAME_SIZE];
450
451         if (unlikely(!q)) {
452                 DMWARN("%s: Cannot set limits for nonexistent device %s",
453                        dm_device_name(ti->table->md), bdevname(bdev, b));
454                 return 0;
455         }
456
457         if (bdev_stack_limits(limits, bdev, start) < 0)
458                 DMWARN("%s: adding target device %s caused an alignment inconsistency: "
459                        "physical_block_size=%u, logical_block_size=%u, "
460                        "alignment_offset=%u, start=%llu",
461                        dm_device_name(ti->table->md), bdevname(bdev, b),
462                        q->limits.physical_block_size,
463                        q->limits.logical_block_size,
464                        q->limits.alignment_offset,
465                        (unsigned long long) start << SECTOR_SHIFT);
466
467         return 0;
468 }
469
470 /*
471  * Decrement a device's use count and remove it if necessary.
472  */
473 void dm_put_device(struct dm_target *ti, struct dm_dev *d)
474 {
475         int found = 0;
476         struct list_head *devices = &ti->table->devices;
477         struct dm_dev_internal *dd;
478
479         list_for_each_entry(dd, devices, list) {
480                 if (dd->dm_dev == d) {
481                         found = 1;
482                         break;
483                 }
484         }
485         if (!found) {
486                 DMWARN("%s: device %s not in table devices list",
487                        dm_device_name(ti->table->md), d->name);
488                 return;
489         }
490         if (atomic_dec_and_test(&dd->count)) {
491                 dm_put_table_device(ti->table->md, d);
492                 list_del(&dd->list);
493                 kfree(dd);
494         }
495 }
496 EXPORT_SYMBOL(dm_put_device);
497
498 /*
499  * Checks to see if the target joins onto the end of the table.
500  */
501 static int adjoin(struct dm_table *table, struct dm_target *ti)
502 {
503         struct dm_target *prev;
504
505         if (!table->num_targets)
506                 return !ti->begin;
507
508         prev = &table->targets[table->num_targets - 1];
509         return (ti->begin == (prev->begin + prev->len));
510 }
511
512 /*
513  * Used to dynamically allocate the arg array.
514  *
515  * We do first allocation with GFP_NOIO because dm-mpath and dm-thin must
516  * process messages even if some device is suspended. These messages have a
517  * small fixed number of arguments.
518  *
519  * On the other hand, dm-switch needs to process bulk data using messages and
520  * excessive use of GFP_NOIO could cause trouble.
521  */
522 static char **realloc_argv(unsigned *size, char **old_argv)
523 {
524         char **argv;
525         unsigned new_size;
526         gfp_t gfp;
527
528         if (*size) {
529                 new_size = *size * 2;
530                 gfp = GFP_KERNEL;
531         } else {
532                 new_size = 8;
533                 gfp = GFP_NOIO;
534         }
535         argv = kmalloc(new_size * sizeof(*argv), gfp);
536         if (argv) {
537                 memcpy(argv, old_argv, *size * sizeof(*argv));
538                 *size = new_size;
539         }
540
541         kfree(old_argv);
542         return argv;
543 }
544
545 /*
546  * Destructively splits up the argument list to pass to ctr.
547  */
548 int dm_split_args(int *argc, char ***argvp, char *input)
549 {
550         char *start, *end = input, *out, **argv = NULL;
551         unsigned array_size = 0;
552
553         *argc = 0;
554
555         if (!input) {
556                 *argvp = NULL;
557                 return 0;
558         }
559
560         argv = realloc_argv(&array_size, argv);
561         if (!argv)
562                 return -ENOMEM;
563
564         while (1) {
565                 /* Skip whitespace */
566                 start = skip_spaces(end);
567
568                 if (!*start)
569                         break;  /* success, we hit the end */
570
571                 /* 'out' is used to remove any back-quotes */
572                 end = out = start;
573                 while (*end) {
574                         /* Everything apart from '\0' can be quoted */
575                         if (*end == '\\' && *(end + 1)) {
576                                 *out++ = *(end + 1);
577                                 end += 2;
578                                 continue;
579                         }
580
581                         if (isspace(*end))
582                                 break;  /* end of token */
583
584                         *out++ = *end++;
585                 }
586
587                 /* have we already filled the array ? */
588                 if ((*argc + 1) > array_size) {
589                         argv = realloc_argv(&array_size, argv);
590                         if (!argv)
591                                 return -ENOMEM;
592                 }
593
594                 /* we know this is whitespace */
595                 if (*end)
596                         end++;
597
598                 /* terminate the string and put it in the array */
599                 *out = '\0';
600                 argv[*argc] = start;
601                 (*argc)++;
602         }
603
604         *argvp = argv;
605         return 0;
606 }
607
608 /*
609  * Impose necessary and sufficient conditions on a devices's table such
610  * that any incoming bio which respects its logical_block_size can be
611  * processed successfully.  If it falls across the boundary between
612  * two or more targets, the size of each piece it gets split into must
613  * be compatible with the logical_block_size of the target processing it.
614  */
615 static int validate_hardware_logical_block_alignment(struct dm_table *table,
616                                                  struct queue_limits *limits)
617 {
618         /*
619          * This function uses arithmetic modulo the logical_block_size
620          * (in units of 512-byte sectors).
621          */
622         unsigned short device_logical_block_size_sects =
623                 limits->logical_block_size >> SECTOR_SHIFT;
624
625         /*
626          * Offset of the start of the next table entry, mod logical_block_size.
627          */
628         unsigned short next_target_start = 0;
629
630         /*
631          * Given an aligned bio that extends beyond the end of a
632          * target, how many sectors must the next target handle?
633          */
634         unsigned short remaining = 0;
635
636         struct dm_target *uninitialized_var(ti);
637         struct queue_limits ti_limits;
638         unsigned i = 0;
639
640         /*
641          * Check each entry in the table in turn.
642          */
643         while (i < dm_table_get_num_targets(table)) {
644                 ti = dm_table_get_target(table, i++);
645
646                 blk_set_stacking_limits(&ti_limits);
647
648                 /* combine all target devices' limits */
649                 if (ti->type->iterate_devices)
650                         ti->type->iterate_devices(ti, dm_set_device_limits,
651                                                   &ti_limits);
652
653                 /*
654                  * If the remaining sectors fall entirely within this
655                  * table entry are they compatible with its logical_block_size?
656                  */
657                 if (remaining < ti->len &&
658                     remaining & ((ti_limits.logical_block_size >>
659                                   SECTOR_SHIFT) - 1))
660                         break;  /* Error */
661
662                 next_target_start =
663                     (unsigned short) ((next_target_start + ti->len) &
664                                       (device_logical_block_size_sects - 1));
665                 remaining = next_target_start ?
666                     device_logical_block_size_sects - next_target_start : 0;
667         }
668
669         if (remaining) {
670                 DMWARN("%s: table line %u (start sect %llu len %llu) "
671                        "not aligned to h/w logical block size %u",
672                        dm_device_name(table->md), i,
673                        (unsigned long long) ti->begin,
674                        (unsigned long long) ti->len,
675                        limits->logical_block_size);
676                 return -EINVAL;
677         }
678
679         return 0;
680 }
681
682 int dm_table_add_target(struct dm_table *t, const char *type,
683                         sector_t start, sector_t len, char *params)
684 {
685         int r = -EINVAL, argc;
686         char **argv;
687         struct dm_target *tgt;
688
689         if (t->singleton) {
690                 DMERR("%s: target type %s must appear alone in table",
691                       dm_device_name(t->md), t->targets->type->name);
692                 return -EINVAL;
693         }
694
695         BUG_ON(t->num_targets >= t->num_allocated);
696
697         tgt = t->targets + t->num_targets;
698         memset(tgt, 0, sizeof(*tgt));
699
700         if (!len) {
701                 DMERR("%s: zero-length target", dm_device_name(t->md));
702                 return -EINVAL;
703         }
704
705         tgt->type = dm_get_target_type(type);
706         if (!tgt->type) {
707                 DMERR("%s: %s: unknown target type", dm_device_name(t->md), type);
708                 return -EINVAL;
709         }
710
711         if (dm_target_needs_singleton(tgt->type)) {
712                 if (t->num_targets) {
713                         tgt->error = "singleton target type must appear alone in table";
714                         goto bad;
715                 }
716                 t->singleton = true;
717         }
718
719         if (dm_target_always_writeable(tgt->type) && !(t->mode & FMODE_WRITE)) {
720                 tgt->error = "target type may not be included in a read-only table";
721                 goto bad;
722         }
723
724         if (t->immutable_target_type) {
725                 if (t->immutable_target_type != tgt->type) {
726                         tgt->error = "immutable target type cannot be mixed with other target types";
727                         goto bad;
728                 }
729         } else if (dm_target_is_immutable(tgt->type)) {
730                 if (t->num_targets) {
731                         tgt->error = "immutable target type cannot be mixed with other target types";
732                         goto bad;
733                 }
734                 t->immutable_target_type = tgt->type;
735         }
736
737         tgt->table = t;
738         tgt->begin = start;
739         tgt->len = len;
740         tgt->error = "Unknown error";
741
742         /*
743          * Does this target adjoin the previous one ?
744          */
745         if (!adjoin(t, tgt)) {
746                 tgt->error = "Gap in table";
747                 goto bad;
748         }
749
750         r = dm_split_args(&argc, &argv, params);
751         if (r) {
752                 tgt->error = "couldn't split parameters (insufficient memory)";
753                 goto bad;
754         }
755
756         r = tgt->type->ctr(tgt, argc, argv);
757         kfree(argv);
758         if (r)
759                 goto bad;
760
761         t->highs[t->num_targets++] = tgt->begin + tgt->len - 1;
762
763         if (!tgt->num_discard_bios && tgt->discards_supported)
764                 DMWARN("%s: %s: ignoring discards_supported because num_discard_bios is zero.",
765                        dm_device_name(t->md), type);
766
767         return 0;
768
769  bad:
770         DMERR("%s: %s: %s", dm_device_name(t->md), type, tgt->error);
771         dm_put_target_type(tgt->type);
772         return r;
773 }
774
775 /*
776  * Target argument parsing helpers.
777  */
778 static int validate_next_arg(struct dm_arg *arg, struct dm_arg_set *arg_set,
779                              unsigned *value, char **error, unsigned grouped)
780 {
781         const char *arg_str = dm_shift_arg(arg_set);
782         char dummy;
783
784         if (!arg_str ||
785             (sscanf(arg_str, "%u%c", value, &dummy) != 1) ||
786             (*value < arg->min) ||
787             (*value > arg->max) ||
788             (grouped && arg_set->argc < *value)) {
789                 *error = arg->error;
790                 return -EINVAL;
791         }
792
793         return 0;
794 }
795
796 int dm_read_arg(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, 0);
800 }
801 EXPORT_SYMBOL(dm_read_arg);
802
803 int dm_read_arg_group(struct dm_arg *arg, struct dm_arg_set *arg_set,
804                       unsigned *value, char **error)
805 {
806         return validate_next_arg(arg, arg_set, value, error, 1);
807 }
808 EXPORT_SYMBOL(dm_read_arg_group);
809
810 const char *dm_shift_arg(struct dm_arg_set *as)
811 {
812         char *r;
813
814         if (as->argc) {
815                 as->argc--;
816                 r = *as->argv;
817                 as->argv++;
818                 return r;
819         }
820
821         return NULL;
822 }
823 EXPORT_SYMBOL(dm_shift_arg);
824
825 void dm_consume_args(struct dm_arg_set *as, unsigned num_args)
826 {
827         BUG_ON(as->argc < num_args);
828         as->argc -= num_args;
829         as->argv += num_args;
830 }
831 EXPORT_SYMBOL(dm_consume_args);
832
833 static bool __table_type_bio_based(unsigned table_type)
834 {
835         return (table_type == DM_TYPE_BIO_BASED ||
836                 table_type == DM_TYPE_DAX_BIO_BASED);
837 }
838
839 static bool __table_type_request_based(unsigned table_type)
840 {
841         return (table_type == DM_TYPE_REQUEST_BASED ||
842                 table_type == DM_TYPE_MQ_REQUEST_BASED);
843 }
844
845 void dm_table_set_type(struct dm_table *t, unsigned type)
846 {
847         t->type = type;
848 }
849 EXPORT_SYMBOL_GPL(dm_table_set_type);
850
851 static int device_not_dax_capable(struct dm_target *ti, struct dm_dev *dev,
852                                   sector_t start, sector_t len, void *data)
853 {
854         struct request_queue *q = bdev_get_queue(dev->bdev);
855
856         return q && !blk_queue_dax(q);
857 }
858
859 static bool dm_table_supports_dax(struct dm_table *t)
860 {
861         struct dm_target *ti;
862         unsigned i = 0;
863
864         /* Ensure that all targets support DAX. */
865         while (i < dm_table_get_num_targets(t)) {
866                 ti = dm_table_get_target(t, i++);
867
868                 if (!ti->type->direct_access)
869                         return false;
870
871                 if (!ti->type->iterate_devices ||
872                     ti->type->iterate_devices(ti, device_not_dax_capable, NULL))
873                         return false;
874         }
875
876         return true;
877 }
878
879 static int dm_table_determine_type(struct dm_table *t)
880 {
881         unsigned i;
882         unsigned bio_based = 0, request_based = 0, hybrid = 0;
883         bool verify_blk_mq = false;
884         struct dm_target *tgt;
885         struct dm_dev_internal *dd;
886         struct list_head *devices = dm_table_get_devices(t);
887         unsigned live_md_type = dm_get_md_type(t->md);
888
889         if (t->type != DM_TYPE_NONE) {
890                 /* target already set the table's type */
891                 if (t->type == DM_TYPE_BIO_BASED)
892                         return 0;
893                 BUG_ON(t->type == DM_TYPE_DAX_BIO_BASED);
894                 goto verify_rq_based;
895         }
896
897         for (i = 0; i < t->num_targets; i++) {
898                 tgt = t->targets + i;
899                 if (dm_target_hybrid(tgt))
900                         hybrid = 1;
901                 else if (dm_target_request_based(tgt))
902                         request_based = 1;
903                 else
904                         bio_based = 1;
905
906                 if (bio_based && request_based) {
907                         DMWARN("Inconsistent table: different target types"
908                                " can't be mixed up");
909                         return -EINVAL;
910                 }
911         }
912
913         if (hybrid && !bio_based && !request_based) {
914                 /*
915                  * The targets can work either way.
916                  * Determine the type from the live device.
917                  * Default to bio-based if device is new.
918                  */
919                 if (__table_type_request_based(live_md_type))
920                         request_based = 1;
921                 else
922                         bio_based = 1;
923         }
924
925         if (bio_based) {
926                 /* We must use this table as bio-based */
927                 t->type = DM_TYPE_BIO_BASED;
928                 if (dm_table_supports_dax(t) ||
929                     (list_empty(devices) && live_md_type == DM_TYPE_DAX_BIO_BASED))
930                         t->type = DM_TYPE_DAX_BIO_BASED;
931                 return 0;
932         }
933
934         BUG_ON(!request_based); /* No targets in this table */
935
936         /*
937          * The only way to establish DM_TYPE_MQ_REQUEST_BASED is by
938          * having a compatible target use dm_table_set_type.
939          */
940         t->type = DM_TYPE_REQUEST_BASED;
941
942 verify_rq_based:
943         /*
944          * Request-based dm supports only tables that have a single target now.
945          * To support multiple targets, request splitting support is needed,
946          * and that needs lots of changes in the block-layer.
947          * (e.g. request completion process for partial completion.)
948          */
949         if (t->num_targets > 1) {
950                 DMWARN("Request-based dm doesn't support multiple targets yet");
951                 return -EINVAL;
952         }
953
954         if (list_empty(devices)) {
955                 int srcu_idx;
956                 struct dm_table *live_table = dm_get_live_table(t->md, &srcu_idx);
957
958                 /* inherit live table's type and all_blk_mq */
959                 if (live_table) {
960                         t->type = live_table->type;
961                         t->all_blk_mq = live_table->all_blk_mq;
962                 }
963                 dm_put_live_table(t->md, srcu_idx);
964                 return 0;
965         }
966
967         /* Non-request-stackable devices can't be used for request-based dm */
968         list_for_each_entry(dd, devices, list) {
969                 struct request_queue *q = bdev_get_queue(dd->dm_dev->bdev);
970
971                 if (!blk_queue_stackable(q)) {
972                         DMERR("table load rejected: including"
973                               " non-request-stackable devices");
974                         return -EINVAL;
975                 }
976
977                 if (q->mq_ops)
978                         verify_blk_mq = true;
979         }
980
981         if (verify_blk_mq) {
982                 /* verify _all_ devices in the table are blk-mq devices */
983                 list_for_each_entry(dd, devices, list)
984                         if (!bdev_get_queue(dd->dm_dev->bdev)->mq_ops) {
985                                 DMERR("table load rejected: not all devices"
986                                       " are blk-mq request-stackable");
987                                 return -EINVAL;
988                         }
989
990                 t->all_blk_mq = true;
991         }
992
993         if (t->type == DM_TYPE_MQ_REQUEST_BASED && !t->all_blk_mq) {
994                 DMERR("table load rejected: all devices are not blk-mq request-stackable");
995                 return -EINVAL;
996         }
997
998         return 0;
999 }
1000
1001 unsigned dm_table_get_type(struct dm_table *t)
1002 {
1003         return t->type;
1004 }
1005
1006 struct target_type *dm_table_get_immutable_target_type(struct dm_table *t)
1007 {
1008         return t->immutable_target_type;
1009 }
1010
1011 struct dm_target *dm_table_get_immutable_target(struct dm_table *t)
1012 {
1013         /* Immutable target is implicitly a singleton */
1014         if (t->num_targets > 1 ||
1015             !dm_target_is_immutable(t->targets[0].type))
1016                 return NULL;
1017
1018         return t->targets;
1019 }
1020
1021 struct dm_target *dm_table_get_wildcard_target(struct dm_table *t)
1022 {
1023         struct dm_target *uninitialized_var(ti);
1024         unsigned i = 0;
1025
1026         while (i < dm_table_get_num_targets(t)) {
1027                 ti = dm_table_get_target(t, i++);
1028                 if (dm_target_is_wildcard(ti->type))
1029                         return ti;
1030         }
1031
1032         return NULL;
1033 }
1034
1035 bool dm_table_bio_based(struct dm_table *t)
1036 {
1037         return __table_type_bio_based(dm_table_get_type(t));
1038 }
1039
1040 bool dm_table_request_based(struct dm_table *t)
1041 {
1042         return __table_type_request_based(dm_table_get_type(t));
1043 }
1044
1045 bool dm_table_all_blk_mq_devices(struct dm_table *t)
1046 {
1047         return t->all_blk_mq;
1048 }
1049
1050 static int dm_table_alloc_md_mempools(struct dm_table *t, struct mapped_device *md)
1051 {
1052         unsigned type = dm_table_get_type(t);
1053         unsigned per_io_data_size = 0;
1054         struct dm_target *tgt;
1055         unsigned i;
1056
1057         if (unlikely(type == DM_TYPE_NONE)) {
1058                 DMWARN("no table type is set, can't allocate mempools");
1059                 return -EINVAL;
1060         }
1061
1062         if (__table_type_bio_based(type))
1063                 for (i = 0; i < t->num_targets; i++) {
1064                         tgt = t->targets + i;
1065                         per_io_data_size = max(per_io_data_size, tgt->per_io_data_size);
1066                 }
1067
1068         t->mempools = dm_alloc_md_mempools(md, type, t->integrity_supported, per_io_data_size);
1069         if (!t->mempools)
1070                 return -ENOMEM;
1071
1072         return 0;
1073 }
1074
1075 void dm_table_free_md_mempools(struct dm_table *t)
1076 {
1077         dm_free_md_mempools(t->mempools);
1078         t->mempools = NULL;
1079 }
1080
1081 struct dm_md_mempools *dm_table_get_md_mempools(struct dm_table *t)
1082 {
1083         return t->mempools;
1084 }
1085
1086 static int setup_indexes(struct dm_table *t)
1087 {
1088         int i;
1089         unsigned int total = 0;
1090         sector_t *indexes;
1091
1092         /* allocate the space for *all* the indexes */
1093         for (i = t->depth - 2; i >= 0; i--) {
1094                 t->counts[i] = dm_div_up(t->counts[i + 1], CHILDREN_PER_NODE);
1095                 total += t->counts[i];
1096         }
1097
1098         indexes = (sector_t *) dm_vcalloc(total, (unsigned long) NODE_SIZE);
1099         if (!indexes)
1100                 return -ENOMEM;
1101
1102         /* set up internal nodes, bottom-up */
1103         for (i = t->depth - 2; i >= 0; i--) {
1104                 t->index[i] = indexes;
1105                 indexes += (KEYS_PER_NODE * t->counts[i]);
1106                 setup_btree_index(i, t);
1107         }
1108
1109         return 0;
1110 }
1111
1112 /*
1113  * Builds the btree to index the map.
1114  */
1115 static int dm_table_build_index(struct dm_table *t)
1116 {
1117         int r = 0;
1118         unsigned int leaf_nodes;
1119
1120         /* how many indexes will the btree have ? */
1121         leaf_nodes = dm_div_up(t->num_targets, KEYS_PER_NODE);
1122         t->depth = 1 + int_log(leaf_nodes, CHILDREN_PER_NODE);
1123
1124         /* leaf layer has already been set up */
1125         t->counts[t->depth - 1] = leaf_nodes;
1126         t->index[t->depth - 1] = t->highs;
1127
1128         if (t->depth >= 2)
1129                 r = setup_indexes(t);
1130
1131         return r;
1132 }
1133
1134 static bool integrity_profile_exists(struct gendisk *disk)
1135 {
1136         return !!blk_get_integrity(disk);
1137 }
1138
1139 /*
1140  * Get a disk whose integrity profile reflects the table's profile.
1141  * Returns NULL if integrity support was inconsistent or unavailable.
1142  */
1143 static struct gendisk * dm_table_get_integrity_disk(struct dm_table *t)
1144 {
1145         struct list_head *devices = dm_table_get_devices(t);
1146         struct dm_dev_internal *dd = NULL;
1147         struct gendisk *prev_disk = NULL, *template_disk = NULL;
1148
1149         list_for_each_entry(dd, devices, list) {
1150                 template_disk = dd->dm_dev->bdev->bd_disk;
1151                 if (!integrity_profile_exists(template_disk))
1152                         goto no_integrity;
1153                 else if (prev_disk &&
1154                          blk_integrity_compare(prev_disk, template_disk) < 0)
1155                         goto no_integrity;
1156                 prev_disk = template_disk;
1157         }
1158
1159         return template_disk;
1160
1161 no_integrity:
1162         if (prev_disk)
1163                 DMWARN("%s: integrity not set: %s and %s profile mismatch",
1164                        dm_device_name(t->md),
1165                        prev_disk->disk_name,
1166                        template_disk->disk_name);
1167         return NULL;
1168 }
1169
1170 /*
1171  * Register the mapped device for blk_integrity support if the
1172  * underlying devices have an integrity profile.  But all devices may
1173  * not have matching profiles (checking all devices isn't reliable
1174  * during table load because this table may use other DM device(s) which
1175  * must be resumed before they will have an initialized integity
1176  * profile).  Consequently, stacked DM devices force a 2 stage integrity
1177  * profile validation: First pass during table load, final pass during
1178  * resume.
1179  */
1180 static int dm_table_register_integrity(struct dm_table *t)
1181 {
1182         struct mapped_device *md = t->md;
1183         struct gendisk *template_disk = NULL;
1184
1185         template_disk = dm_table_get_integrity_disk(t);
1186         if (!template_disk)
1187                 return 0;
1188
1189         if (!integrity_profile_exists(dm_disk(md))) {
1190                 t->integrity_supported = true;
1191                 /*
1192                  * Register integrity profile during table load; we can do
1193                  * this because the final profile must match during resume.
1194                  */
1195                 blk_integrity_register(dm_disk(md),
1196                                        blk_get_integrity(template_disk));
1197                 return 0;
1198         }
1199
1200         /*
1201          * If DM device already has an initialized integrity
1202          * profile the new profile should not conflict.
1203          */
1204         if (blk_integrity_compare(dm_disk(md), template_disk) < 0) {
1205                 DMWARN("%s: conflict with existing integrity profile: "
1206                        "%s profile mismatch",
1207                        dm_device_name(t->md),
1208                        template_disk->disk_name);
1209                 return 1;
1210         }
1211
1212         /* Preserve existing integrity profile */
1213         t->integrity_supported = true;
1214         return 0;
1215 }
1216
1217 /*
1218  * Prepares the table for use by building the indices,
1219  * setting the type, and allocating mempools.
1220  */
1221 int dm_table_complete(struct dm_table *t)
1222 {
1223         int r;
1224
1225         r = dm_table_determine_type(t);
1226         if (r) {
1227                 DMERR("unable to determine table type");
1228                 return r;
1229         }
1230
1231         r = dm_table_build_index(t);
1232         if (r) {
1233                 DMERR("unable to build btrees");
1234                 return r;
1235         }
1236
1237         r = dm_table_register_integrity(t);
1238         if (r) {
1239                 DMERR("could not register integrity profile.");
1240                 return r;
1241         }
1242
1243         r = dm_table_alloc_md_mempools(t, t->md);
1244         if (r)
1245                 DMERR("unable to allocate mempools");
1246
1247         return r;
1248 }
1249
1250 static DEFINE_MUTEX(_event_lock);
1251 void dm_table_event_callback(struct dm_table *t,
1252                              void (*fn)(void *), void *context)
1253 {
1254         mutex_lock(&_event_lock);
1255         t->event_fn = fn;
1256         t->event_context = context;
1257         mutex_unlock(&_event_lock);
1258 }
1259
1260 void dm_table_event(struct dm_table *t)
1261 {
1262         mutex_lock(&_event_lock);
1263         if (t->event_fn)
1264                 t->event_fn(t->event_context);
1265         mutex_unlock(&_event_lock);
1266 }
1267 EXPORT_SYMBOL(dm_table_event);
1268
1269 inline sector_t dm_table_get_size(struct dm_table *t)
1270 {
1271         return t->num_targets ? (t->highs[t->num_targets - 1] + 1) : 0;
1272 }
1273 EXPORT_SYMBOL(dm_table_get_size);
1274
1275 struct dm_target *dm_table_get_target(struct dm_table *t, unsigned int index)
1276 {
1277         if (index >= t->num_targets)
1278                 return NULL;
1279
1280         return t->targets + index;
1281 }
1282
1283 /*
1284  * Search the btree for the correct target.
1285  *
1286  * Caller should check returned pointer with dm_target_is_valid()
1287  * to trap I/O beyond end of device.
1288  */
1289 struct dm_target *dm_table_find_target(struct dm_table *t, sector_t sector)
1290 {
1291         unsigned int l, n = 0, k = 0;
1292         sector_t *node;
1293
1294         if (unlikely(sector >= dm_table_get_size(t)))
1295                 return &t->targets[t->num_targets];
1296
1297         for (l = 0; l < t->depth; l++) {
1298                 n = get_child(n, k);
1299                 node = get_node(t, l, n);
1300
1301                 for (k = 0; k < KEYS_PER_NODE; k++)
1302                         if (node[k] >= sector)
1303                                 break;
1304         }
1305
1306         return &t->targets[(KEYS_PER_NODE * n) + k];
1307 }
1308
1309 /*
1310  * type->iterate_devices() should be called when the sanity check needs to
1311  * iterate and check all underlying data devices. iterate_devices() will
1312  * iterate all underlying data devices until it encounters a non-zero return
1313  * code, returned by whether the input iterate_devices_callout_fn, or
1314  * iterate_devices() itself internally.
1315  *
1316  * For some target type (e.g. dm-stripe), one call of iterate_devices() may
1317  * iterate multiple underlying devices internally, in which case a non-zero
1318  * return code returned by iterate_devices_callout_fn will stop the iteration
1319  * in advance.
1320  *
1321  * Cases requiring _any_ underlying device supporting some kind of attribute,
1322  * should use the iteration structure like dm_table_any_dev_attr(), or call
1323  * it directly. @func should handle semantics of positive examples, e.g.
1324  * capable of something.
1325  *
1326  * Cases requiring _all_ underlying devices supporting some kind of attribute,
1327  * should use the iteration structure like dm_table_supports_nowait() or
1328  * dm_table_supports_discards(). Or introduce dm_table_all_devs_attr() that
1329  * uses an @anti_func that handle semantics of counter examples, e.g. not
1330  * capable of something. So: return !dm_table_any_dev_attr(t, anti_func);
1331  */
1332 static bool dm_table_any_dev_attr(struct dm_table *t,
1333                                   iterate_devices_callout_fn func)
1334 {
1335         struct dm_target *ti;
1336         unsigned int i;
1337
1338         for (i = 0; i < dm_table_get_num_targets(t); i++) {
1339                 ti = dm_table_get_target(t, i);
1340
1341                 if (ti->type->iterate_devices &&
1342                     ti->type->iterate_devices(ti, func, NULL))
1343                         return true;
1344         }
1345
1346         return false;
1347 }
1348
1349 static int count_device(struct dm_target *ti, struct dm_dev *dev,
1350                         sector_t start, sector_t len, void *data)
1351 {
1352         unsigned *num_devices = data;
1353
1354         (*num_devices)++;
1355
1356         return 0;
1357 }
1358
1359 /*
1360  * Check whether a table has no data devices attached using each
1361  * target's iterate_devices method.
1362  * Returns false if the result is unknown because a target doesn't
1363  * support iterate_devices.
1364  */
1365 bool dm_table_has_no_data_devices(struct dm_table *table)
1366 {
1367         struct dm_target *uninitialized_var(ti);
1368         unsigned i = 0, num_devices = 0;
1369
1370         while (i < dm_table_get_num_targets(table)) {
1371                 ti = dm_table_get_target(table, i++);
1372
1373                 if (!ti->type->iterate_devices)
1374                         return false;
1375
1376                 ti->type->iterate_devices(ti, count_device, &num_devices);
1377                 if (num_devices)
1378                         return false;
1379         }
1380
1381         return true;
1382 }
1383
1384 /*
1385  * Establish the new table's queue_limits and validate them.
1386  */
1387 int dm_calculate_queue_limits(struct dm_table *table,
1388                               struct queue_limits *limits)
1389 {
1390         struct dm_target *uninitialized_var(ti);
1391         struct queue_limits ti_limits;
1392         unsigned i = 0;
1393
1394         blk_set_stacking_limits(limits);
1395
1396         while (i < dm_table_get_num_targets(table)) {
1397                 blk_set_stacking_limits(&ti_limits);
1398
1399                 ti = dm_table_get_target(table, i++);
1400
1401                 if (!ti->type->iterate_devices)
1402                         goto combine_limits;
1403
1404                 /*
1405                  * Combine queue limits of all the devices this target uses.
1406                  */
1407                 ti->type->iterate_devices(ti, dm_set_device_limits,
1408                                           &ti_limits);
1409
1410                 /* Set I/O hints portion of queue limits */
1411                 if (ti->type->io_hints)
1412                         ti->type->io_hints(ti, &ti_limits);
1413
1414                 /*
1415                  * Check each device area is consistent with the target's
1416                  * overall queue limits.
1417                  */
1418                 if (ti->type->iterate_devices(ti, device_area_is_invalid,
1419                                               &ti_limits))
1420                         return -EINVAL;
1421
1422 combine_limits:
1423                 /*
1424                  * Merge this target's queue limits into the overall limits
1425                  * for the table.
1426                  */
1427                 if (blk_stack_limits(limits, &ti_limits, 0) < 0)
1428                         DMWARN("%s: adding target device "
1429                                "(start sect %llu len %llu) "
1430                                "caused an alignment inconsistency",
1431                                dm_device_name(table->md),
1432                                (unsigned long long) ti->begin,
1433                                (unsigned long long) ti->len);
1434         }
1435
1436         return validate_hardware_logical_block_alignment(table, limits);
1437 }
1438
1439 /*
1440  * Verify that all devices have an integrity profile that matches the
1441  * DM device's registered integrity profile.  If the profiles don't
1442  * match then unregister the DM device's integrity profile.
1443  */
1444 static void dm_table_verify_integrity(struct dm_table *t)
1445 {
1446         struct gendisk *template_disk = NULL;
1447
1448         if (t->integrity_supported) {
1449                 /*
1450                  * Verify that the original integrity profile
1451                  * matches all the devices in this table.
1452                  */
1453                 template_disk = dm_table_get_integrity_disk(t);
1454                 if (template_disk &&
1455                     blk_integrity_compare(dm_disk(t->md), template_disk) >= 0)
1456                         return;
1457         }
1458
1459         if (integrity_profile_exists(dm_disk(t->md))) {
1460                 DMWARN("%s: unable to establish an integrity profile",
1461                        dm_device_name(t->md));
1462                 blk_integrity_unregister(dm_disk(t->md));
1463         }
1464 }
1465
1466 static int device_flush_capable(struct dm_target *ti, struct dm_dev *dev,
1467                                 sector_t start, sector_t len, void *data)
1468 {
1469         unsigned long flush = (unsigned long) data;
1470         struct request_queue *q = bdev_get_queue(dev->bdev);
1471
1472         return q && (q->queue_flags & flush);
1473 }
1474
1475 static bool dm_table_supports_flush(struct dm_table *t, unsigned long flush)
1476 {
1477         struct dm_target *ti;
1478         unsigned i = 0;
1479
1480         /*
1481          * Require at least one underlying device to support flushes.
1482          * t->devices includes internal dm devices such as mirror logs
1483          * so we need to use iterate_devices here, which targets
1484          * supporting flushes must provide.
1485          */
1486         while (i < dm_table_get_num_targets(t)) {
1487                 ti = dm_table_get_target(t, i++);
1488
1489                 if (!ti->num_flush_bios)
1490                         continue;
1491
1492                 if (ti->flush_supported)
1493                         return true;
1494
1495                 if (ti->type->iterate_devices &&
1496                     ti->type->iterate_devices(ti, device_flush_capable, (void *) flush))
1497                         return true;
1498         }
1499
1500         return false;
1501 }
1502
1503 static bool dm_table_discard_zeroes_data(struct dm_table *t)
1504 {
1505         struct dm_target *ti;
1506         unsigned i = 0;
1507
1508         /* Ensure that all targets supports discard_zeroes_data. */
1509         while (i < dm_table_get_num_targets(t)) {
1510                 ti = dm_table_get_target(t, i++);
1511
1512                 if (ti->discard_zeroes_data_unsupported)
1513                         return false;
1514         }
1515
1516         return true;
1517 }
1518
1519 static int device_is_rotational(struct dm_target *ti, struct dm_dev *dev,
1520                                 sector_t start, sector_t len, void *data)
1521 {
1522         struct request_queue *q = bdev_get_queue(dev->bdev);
1523
1524         return q && !blk_queue_nonrot(q);
1525 }
1526
1527 static int device_is_not_random(struct dm_target *ti, struct dm_dev *dev,
1528                              sector_t start, sector_t len, void *data)
1529 {
1530         struct request_queue *q = bdev_get_queue(dev->bdev);
1531
1532         return q && !blk_queue_add_random(q);
1533 }
1534
1535 static int queue_no_sg_merge(struct dm_target *ti, struct dm_dev *dev,
1536                              sector_t start, sector_t len, void *data)
1537 {
1538         struct request_queue *q = bdev_get_queue(dev->bdev);
1539
1540         return q && test_bit(QUEUE_FLAG_NO_SG_MERGE, &q->queue_flags);
1541 }
1542
1543 static int device_not_write_same_capable(struct dm_target *ti, struct dm_dev *dev,
1544                                          sector_t start, sector_t len, void *data)
1545 {
1546         struct request_queue *q = bdev_get_queue(dev->bdev);
1547
1548         return q && !q->limits.max_write_same_sectors;
1549 }
1550
1551 static bool dm_table_supports_write_same(struct dm_table *t)
1552 {
1553         struct dm_target *ti;
1554         unsigned i = 0;
1555
1556         while (i < dm_table_get_num_targets(t)) {
1557                 ti = dm_table_get_target(t, i++);
1558
1559                 if (!ti->num_write_same_bios)
1560                         return false;
1561
1562                 if (!ti->type->iterate_devices ||
1563                     ti->type->iterate_devices(ti, device_not_write_same_capable, NULL))
1564                         return false;
1565         }
1566
1567         return true;
1568 }
1569
1570 static int device_discard_capable(struct dm_target *ti, struct dm_dev *dev,
1571                                   sector_t start, sector_t len, void *data)
1572 {
1573         struct request_queue *q = bdev_get_queue(dev->bdev);
1574
1575         return q && blk_queue_discard(q);
1576 }
1577
1578 static bool dm_table_supports_discards(struct dm_table *t)
1579 {
1580         struct dm_target *ti;
1581         unsigned i = 0;
1582
1583         /*
1584          * Unless any target used by the table set discards_supported,
1585          * require at least one underlying device to support discards.
1586          * t->devices includes internal dm devices such as mirror logs
1587          * so we need to use iterate_devices here, which targets
1588          * supporting discard selectively must provide.
1589          */
1590         while (i < dm_table_get_num_targets(t)) {
1591                 ti = dm_table_get_target(t, i++);
1592
1593                 if (!ti->num_discard_bios)
1594                         continue;
1595
1596                 if (ti->discards_supported)
1597                         return true;
1598
1599                 if (ti->type->iterate_devices &&
1600                     ti->type->iterate_devices(ti, device_discard_capable, NULL))
1601                         return true;
1602         }
1603
1604         return false;
1605 }
1606
1607 void dm_table_set_restrictions(struct dm_table *t, struct request_queue *q,
1608                                struct queue_limits *limits)
1609 {
1610         bool wc = false, fua = false;
1611
1612         /*
1613          * Copy table's limits to the DM device's request_queue
1614          */
1615         q->limits = *limits;
1616
1617         if (!dm_table_supports_discards(t))
1618                 queue_flag_clear_unlocked(QUEUE_FLAG_DISCARD, q);
1619         else
1620                 queue_flag_set_unlocked(QUEUE_FLAG_DISCARD, q);
1621
1622         if (dm_table_supports_flush(t, (1UL << QUEUE_FLAG_WC))) {
1623                 wc = true;
1624                 if (dm_table_supports_flush(t, (1UL << QUEUE_FLAG_FUA)))
1625                         fua = true;
1626         }
1627         blk_queue_write_cache(q, wc, fua);
1628
1629         if (!dm_table_discard_zeroes_data(t))
1630                 q->limits.discard_zeroes_data = 0;
1631
1632         /* Ensure that all underlying devices are non-rotational. */
1633         if (dm_table_any_dev_attr(t, device_is_rotational))
1634                 queue_flag_clear_unlocked(QUEUE_FLAG_NONROT, q);
1635         else
1636                 queue_flag_set_unlocked(QUEUE_FLAG_NONROT, q);
1637
1638         if (!dm_table_supports_write_same(t))
1639                 q->limits.max_write_same_sectors = 0;
1640
1641         if (dm_table_any_dev_attr(t, queue_no_sg_merge))
1642                 queue_flag_set_unlocked(QUEUE_FLAG_NO_SG_MERGE, q);
1643         else
1644                 queue_flag_clear_unlocked(QUEUE_FLAG_NO_SG_MERGE, q);
1645
1646         dm_table_verify_integrity(t);
1647
1648         /*
1649          * Determine whether or not this queue's I/O timings contribute
1650          * to the entropy pool, Only request-based targets use this.
1651          * Clear QUEUE_FLAG_ADD_RANDOM if any underlying device does not
1652          * have it set.
1653          */
1654         if (blk_queue_add_random(q) && dm_table_any_dev_attr(t, device_is_not_random))
1655                 queue_flag_clear_unlocked(QUEUE_FLAG_ADD_RANDOM, q);
1656
1657         /*
1658          * QUEUE_FLAG_STACKABLE must be set after all queue settings are
1659          * visible to other CPUs because, once the flag is set, incoming bios
1660          * are processed by request-based dm, which refers to the queue
1661          * settings.
1662          * Until the flag set, bios are passed to bio-based dm and queued to
1663          * md->deferred where queue settings are not needed yet.
1664          * Those bios are passed to request-based dm at the resume time.
1665          */
1666         smp_mb();
1667         if (dm_table_request_based(t))
1668                 queue_flag_set_unlocked(QUEUE_FLAG_STACKABLE, q);
1669 }
1670
1671 unsigned int dm_table_get_num_targets(struct dm_table *t)
1672 {
1673         return t->num_targets;
1674 }
1675
1676 struct list_head *dm_table_get_devices(struct dm_table *t)
1677 {
1678         return &t->devices;
1679 }
1680
1681 fmode_t dm_table_get_mode(struct dm_table *t)
1682 {
1683         return t->mode;
1684 }
1685 EXPORT_SYMBOL(dm_table_get_mode);
1686
1687 enum suspend_mode {
1688         PRESUSPEND,
1689         PRESUSPEND_UNDO,
1690         POSTSUSPEND,
1691 };
1692
1693 static void suspend_targets(struct dm_table *t, enum suspend_mode mode)
1694 {
1695         int i = t->num_targets;
1696         struct dm_target *ti = t->targets;
1697
1698         while (i--) {
1699                 switch (mode) {
1700                 case PRESUSPEND:
1701                         if (ti->type->presuspend)
1702                                 ti->type->presuspend(ti);
1703                         break;
1704                 case PRESUSPEND_UNDO:
1705                         if (ti->type->presuspend_undo)
1706                                 ti->type->presuspend_undo(ti);
1707                         break;
1708                 case POSTSUSPEND:
1709                         if (ti->type->postsuspend)
1710                                 ti->type->postsuspend(ti);
1711                         break;
1712                 }
1713                 ti++;
1714         }
1715 }
1716
1717 void dm_table_presuspend_targets(struct dm_table *t)
1718 {
1719         if (!t)
1720                 return;
1721
1722         suspend_targets(t, PRESUSPEND);
1723 }
1724
1725 void dm_table_presuspend_undo_targets(struct dm_table *t)
1726 {
1727         if (!t)
1728                 return;
1729
1730         suspend_targets(t, PRESUSPEND_UNDO);
1731 }
1732
1733 void dm_table_postsuspend_targets(struct dm_table *t)
1734 {
1735         if (!t)
1736                 return;
1737
1738         suspend_targets(t, POSTSUSPEND);
1739 }
1740
1741 int dm_table_resume_targets(struct dm_table *t)
1742 {
1743         int i, r = 0;
1744
1745         for (i = 0; i < t->num_targets; i++) {
1746                 struct dm_target *ti = t->targets + i;
1747
1748                 if (!ti->type->preresume)
1749                         continue;
1750
1751                 r = ti->type->preresume(ti);
1752                 if (r) {
1753                         DMERR("%s: %s: preresume failed, error = %d",
1754                               dm_device_name(t->md), ti->type->name, r);
1755                         return r;
1756                 }
1757         }
1758
1759         for (i = 0; i < t->num_targets; i++) {
1760                 struct dm_target *ti = t->targets + i;
1761
1762                 if (ti->type->resume)
1763                         ti->type->resume(ti);
1764         }
1765
1766         return 0;
1767 }
1768
1769 void dm_table_add_target_callbacks(struct dm_table *t, struct dm_target_callbacks *cb)
1770 {
1771         list_add(&cb->list, &t->target_callbacks);
1772 }
1773 EXPORT_SYMBOL_GPL(dm_table_add_target_callbacks);
1774
1775 int dm_table_any_congested(struct dm_table *t, int bdi_bits)
1776 {
1777         struct dm_dev_internal *dd;
1778         struct list_head *devices = dm_table_get_devices(t);
1779         struct dm_target_callbacks *cb;
1780         int r = 0;
1781
1782         list_for_each_entry(dd, devices, list) {
1783                 struct request_queue *q = bdev_get_queue(dd->dm_dev->bdev);
1784                 char b[BDEVNAME_SIZE];
1785
1786                 if (likely(q))
1787                         r |= bdi_congested(&q->backing_dev_info, bdi_bits);
1788                 else
1789                         DMWARN_LIMIT("%s: any_congested: nonexistent device %s",
1790                                      dm_device_name(t->md),
1791                                      bdevname(dd->dm_dev->bdev, b));
1792         }
1793
1794         list_for_each_entry(cb, &t->target_callbacks, list)
1795                 if (cb->congested_fn)
1796                         r |= cb->congested_fn(cb, bdi_bits);
1797
1798         return r;
1799 }
1800
1801 struct mapped_device *dm_table_get_md(struct dm_table *t)
1802 {
1803         return t->md;
1804 }
1805 EXPORT_SYMBOL(dm_table_get_md);
1806
1807 void dm_table_run_md_queue_async(struct dm_table *t)
1808 {
1809         struct mapped_device *md;
1810         struct request_queue *queue;
1811         unsigned long flags;
1812
1813         if (!dm_table_request_based(t))
1814                 return;
1815
1816         md = dm_table_get_md(t);
1817         queue = dm_get_md_queue(md);
1818         if (queue) {
1819                 if (queue->mq_ops)
1820                         blk_mq_run_hw_queues(queue, true);
1821                 else {
1822                         spin_lock_irqsave(queue->queue_lock, flags);
1823                         blk_run_queue_async(queue);
1824                         spin_unlock_irqrestore(queue->queue_lock, flags);
1825                 }
1826         }
1827 }
1828 EXPORT_SYMBOL(dm_table_run_md_queue_async);
1829