1/*
   2 * Copyright (C) 2001, 2002 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#include "dm-uevent.h"
  10
  11#include <linux/init.h>
  12#include <linux/module.h>
  13#include <linux/mutex.h>
  14#include <linux/moduleparam.h>
  15#include <linux/blkpg.h>
  16#include <linux/bio.h>
 
  17#include <linux/mempool.h>
  18#include <linux/slab.h>
  19#include <linux/idr.h>
  20#include <linux/hdreg.h>
  21#include <linux/delay.h>
  22
  23#include <trace/events/block.h>
  24
  25#define DM_MSG_PREFIX "core"
  26
  27#ifdef CONFIG_PRINTK
  28/*
  29 * ratelimit state to be used in DMXXX_LIMIT().
  30 */
  31DEFINE_RATELIMIT_STATE(dm_ratelimit_state,
  32		       DEFAULT_RATELIMIT_INTERVAL,
  33		       DEFAULT_RATELIMIT_BURST);
  34EXPORT_SYMBOL(dm_ratelimit_state);
  35#endif
  36
  37/*
  38 * Cookies are numeric values sent with CHANGE and REMOVE
  39 * uevents while resuming, removing or renaming the device.
  40 */
  41#define DM_COOKIE_ENV_VAR_NAME "DM_COOKIE"
  42#define DM_COOKIE_LENGTH 24
  43
  44static const char *_name = DM_NAME;
  45
  46static unsigned int major = 0;
  47static unsigned int _major = 0;
  48
  49static DEFINE_IDR(_minor_idr);
  50
  51static DEFINE_SPINLOCK(_minor_lock);
  52
  53static void do_deferred_remove(struct work_struct *w);
  54
  55static DECLARE_WORK(deferred_remove_work, do_deferred_remove);
  56
  57/*
  58 * For bio-based dm.
  59 * One of these is allocated per bio.
  60 */
  61struct dm_io {
  62	struct mapped_device *md;
  63	int error;
  64	atomic_t io_count;
  65	struct bio *bio;
  66	unsigned long start_time;
  67	spinlock_t endio_lock;
  68	struct dm_stats_aux stats_aux;
 
 
 
 
 
 
 
 
 
 
  69};
  70
  71/*
  72 * For request-based dm.
  73 * One of these is allocated per request.
  74 */
  75struct dm_rq_target_io {
  76	struct mapped_device *md;
  77	struct dm_target *ti;
  78	struct request *orig, clone;
  79	int error;
  80	union map_info info;
  81};
  82
  83/*
  84 * For request-based dm - the bio clones we allocate are embedded in these
  85 * structs.
  86 *
  87 * We allocate these with bio_alloc_bioset, using the front_pad parameter when
  88 * the bioset is created - this means the bio has to come at the end of the
  89 * struct.
  90 */
  91struct dm_rq_clone_bio_info {
  92	struct bio *orig;
  93	struct dm_rq_target_io *tio;
  94	struct bio clone;
  95};
  96
 
 
 
 
 
 
 
  97union map_info *dm_get_rq_mapinfo(struct request *rq)
  98{
  99	if (rq && rq->end_io_data)
 100		return &((struct dm_rq_target_io *)rq->end_io_data)->info;
 101	return NULL;
 102}
 103EXPORT_SYMBOL_GPL(dm_get_rq_mapinfo);
 104
 105#define MINOR_ALLOCED ((void *)-1)
 106
 107/*
 108 * Bits for the md->flags field.
 109 */
 110#define DMF_BLOCK_IO_FOR_SUSPEND 0
 111#define DMF_SUSPENDED 1
 112#define DMF_FROZEN 2
 113#define DMF_FREEING 3
 114#define DMF_DELETING 4
 115#define DMF_NOFLUSH_SUSPENDING 5
 116#define DMF_MERGE_IS_OPTIONAL 6
 117#define DMF_DEFERRED_REMOVE 7
 118
 119/*
 120 * A dummy definition to make RCU happy.
 121 * struct dm_table should never be dereferenced in this file.
 122 */
 123struct dm_table {
 124	int undefined__;
 125};
 126
 127/*
 128 * Work processed by per-device workqueue.
 129 */
 130struct mapped_device {
 131	struct srcu_struct io_barrier;
 132	struct mutex suspend_lock;
 
 133	atomic_t holders;
 134	atomic_t open_count;
 135
 136	/*
 137	 * The current mapping.
 138	 * Use dm_get_live_table{_fast} or take suspend_lock for
 139	 * dereference.
 140	 */
 141	struct dm_table *map;
 142
 143	unsigned long flags;
 144
 145	struct request_queue *queue;
 146	unsigned type;
 147	/* Protect queue and type against concurrent access. */
 148	struct mutex type_lock;
 149
 150	struct target_type *immutable_target_type;
 151
 152	struct gendisk *disk;
 153	char name[16];
 154
 155	void *interface_ptr;
 156
 157	/*
 158	 * A list of ios that arrived while we were suspended.
 159	 */
 160	atomic_t pending[2];
 161	wait_queue_head_t wait;
 162	struct work_struct work;
 163	struct bio_list deferred;
 164	spinlock_t deferred_lock;
 165
 166	/*
 167	 * Processing queue (flush)
 168	 */
 169	struct workqueue_struct *wq;
 170
 171	/*
 
 
 
 
 
 172	 * io objects are allocated from here.
 173	 */
 174	mempool_t *io_pool;
 
 175
 176	struct bio_set *bs;
 177
 178	/*
 179	 * Event handling.
 180	 */
 181	atomic_t event_nr;
 182	wait_queue_head_t eventq;
 183	atomic_t uevent_seq;
 184	struct list_head uevent_list;
 185	spinlock_t uevent_lock; /* Protect access to uevent_list */
 186
 187	/*
 188	 * freeze/thaw support require holding onto a super block
 189	 */
 190	struct super_block *frozen_sb;
 191	struct block_device *bdev;
 192
 193	/* forced geometry settings */
 194	struct hd_geometry geometry;
 195
 196	/* kobject and completion */
 197	struct dm_kobject_holder kobj_holder;
 
 
 
 198
 199	/* zero-length flush that will be cloned and submitted to targets */
 200	struct bio flush_bio;
 201
 202	struct dm_stats stats;
 203};
 204
 205/*
 206 * For mempools pre-allocation at the table loading time.
 207 */
 208struct dm_md_mempools {
 209	mempool_t *io_pool;
 
 210	struct bio_set *bs;
 211};
 212
 213#define RESERVED_BIO_BASED_IOS		16
 214#define RESERVED_REQUEST_BASED_IOS	256
 215#define RESERVED_MAX_IOS		1024
 216static struct kmem_cache *_io_cache;
 
 217static struct kmem_cache *_rq_tio_cache;
 218
 219/*
 220 * Bio-based DM's mempools' reserved IOs set by the user.
 221 */
 222static unsigned reserved_bio_based_ios = RESERVED_BIO_BASED_IOS;
 223
 224/*
 225 * Request-based DM's mempools' reserved IOs set by the user.
 226 */
 227static unsigned reserved_rq_based_ios = RESERVED_REQUEST_BASED_IOS;
 228
 229static unsigned __dm_get_reserved_ios(unsigned *reserved_ios,
 230				      unsigned def, unsigned max)
 231{
 232	unsigned ios = ACCESS_ONCE(*reserved_ios);
 233	unsigned modified_ios = 0;
 234
 235	if (!ios)
 236		modified_ios = def;
 237	else if (ios > max)
 238		modified_ios = max;
 239
 240	if (modified_ios) {
 241		(void)cmpxchg(reserved_ios, ios, modified_ios);
 242		ios = modified_ios;
 243	}
 244
 245	return ios;
 246}
 247
 248unsigned dm_get_reserved_bio_based_ios(void)
 249{
 250	return __dm_get_reserved_ios(&reserved_bio_based_ios,
 251				     RESERVED_BIO_BASED_IOS, RESERVED_MAX_IOS);
 252}
 253EXPORT_SYMBOL_GPL(dm_get_reserved_bio_based_ios);
 254
 255unsigned dm_get_reserved_rq_based_ios(void)
 256{
 257	return __dm_get_reserved_ios(&reserved_rq_based_ios,
 258				     RESERVED_REQUEST_BASED_IOS, RESERVED_MAX_IOS);
 259}
 260EXPORT_SYMBOL_GPL(dm_get_reserved_rq_based_ios);
 261
 262static int __init local_init(void)
 263{
 264	int r = -ENOMEM;
 265
 266	/* allocate a slab for the dm_ios */
 267	_io_cache = KMEM_CACHE(dm_io, 0);
 268	if (!_io_cache)
 269		return r;
 270
 
 
 
 
 
 271	_rq_tio_cache = KMEM_CACHE(dm_rq_target_io, 0);
 272	if (!_rq_tio_cache)
 273		goto out_free_io_cache;
 
 
 
 
 274
 275	r = dm_uevent_init();
 276	if (r)
 277		goto out_free_rq_tio_cache;
 278
 279	_major = major;
 280	r = register_blkdev(_major, _name);
 281	if (r < 0)
 282		goto out_uevent_exit;
 283
 284	if (!_major)
 285		_major = r;
 286
 287	return 0;
 288
 289out_uevent_exit:
 290	dm_uevent_exit();
 
 
 291out_free_rq_tio_cache:
 292	kmem_cache_destroy(_rq_tio_cache);
 
 
 293out_free_io_cache:
 294	kmem_cache_destroy(_io_cache);
 295
 296	return r;
 297}
 298
 299static void local_exit(void)
 300{
 301	flush_scheduled_work();
 302
 303	kmem_cache_destroy(_rq_tio_cache);
 
 304	kmem_cache_destroy(_io_cache);
 305	unregister_blkdev(_major, _name);
 306	dm_uevent_exit();
 307
 308	_major = 0;
 309
 310	DMINFO("cleaned up");
 311}
 312
 313static int (*_inits[])(void) __initdata = {
 314	local_init,
 315	dm_target_init,
 316	dm_linear_init,
 317	dm_stripe_init,
 318	dm_io_init,
 319	dm_kcopyd_init,
 320	dm_interface_init,
 321	dm_statistics_init,
 322};
 323
 324static void (*_exits[])(void) = {
 325	local_exit,
 326	dm_target_exit,
 327	dm_linear_exit,
 328	dm_stripe_exit,
 329	dm_io_exit,
 330	dm_kcopyd_exit,
 331	dm_interface_exit,
 332	dm_statistics_exit,
 333};
 334
 335static int __init dm_init(void)
 336{
 337	const int count = ARRAY_SIZE(_inits);
 338
 339	int r, i;
 340
 341	for (i = 0; i < count; i++) {
 342		r = _inits[i]();
 343		if (r)
 344			goto bad;
 345	}
 346
 347	return 0;
 348
 349      bad:
 350	while (i--)
 351		_exits[i]();
 352
 353	return r;
 354}
 355
 356static void __exit dm_exit(void)
 357{
 358	int i = ARRAY_SIZE(_exits);
 359
 360	while (i--)
 361		_exits[i]();
 362
 363	/*
 364	 * Should be empty by this point.
 365	 */
 
 366	idr_destroy(&_minor_idr);
 367}
 368
 369/*
 370 * Block device functions
 371 */
 372int dm_deleting_md(struct mapped_device *md)
 373{
 374	return test_bit(DMF_DELETING, &md->flags);
 375}
 376
 377static int dm_blk_open(struct block_device *bdev, fmode_t mode)
 378{
 379	struct mapped_device *md;
 380
 381	spin_lock(&_minor_lock);
 382
 383	md = bdev->bd_disk->private_data;
 384	if (!md)
 385		goto out;
 386
 387	if (test_bit(DMF_FREEING, &md->flags) ||
 388	    dm_deleting_md(md)) {
 389		md = NULL;
 390		goto out;
 391	}
 392
 393	dm_get(md);
 394	atomic_inc(&md->open_count);
 395
 396out:
 397	spin_unlock(&_minor_lock);
 398
 399	return md ? 0 : -ENXIO;
 400}
 401
 402static void dm_blk_close(struct gendisk *disk, fmode_t mode)
 403{
 404	struct mapped_device *md = disk->private_data;
 405
 406	spin_lock(&_minor_lock);
 407
 408	if (atomic_dec_and_test(&md->open_count) &&
 409	    (test_bit(DMF_DEFERRED_REMOVE, &md->flags)))
 410		schedule_work(&deferred_remove_work);
 411
 412	dm_put(md);
 413
 414	spin_unlock(&_minor_lock);
 
 
 415}
 416
 417int dm_open_count(struct mapped_device *md)
 418{
 419	return atomic_read(&md->open_count);
 420}
 421
 422/*
 423 * Guarantees nothing is using the device before it's deleted.
 424 */
 425int dm_lock_for_deletion(struct mapped_device *md, bool mark_deferred, bool only_deferred)
 426{
 427	int r = 0;
 428
 429	spin_lock(&_minor_lock);
 430
 431	if (dm_open_count(md)) {
 432		r = -EBUSY;
 433		if (mark_deferred)
 434			set_bit(DMF_DEFERRED_REMOVE, &md->flags);
 435	} else if (only_deferred && !test_bit(DMF_DEFERRED_REMOVE, &md->flags))
 436		r = -EEXIST;
 437	else
 438		set_bit(DMF_DELETING, &md->flags);
 439
 440	spin_unlock(&_minor_lock);
 441
 442	return r;
 443}
 444
 445int dm_cancel_deferred_remove(struct mapped_device *md)
 446{
 447	int r = 0;
 448
 449	spin_lock(&_minor_lock);
 450
 451	if (test_bit(DMF_DELETING, &md->flags))
 452		r = -EBUSY;
 453	else
 454		clear_bit(DMF_DEFERRED_REMOVE, &md->flags);
 455
 456	spin_unlock(&_minor_lock);
 457
 458	return r;
 459}
 460
 461static void do_deferred_remove(struct work_struct *w)
 462{
 463	dm_deferred_remove();
 464}
 465
 466sector_t dm_get_size(struct mapped_device *md)
 467{
 468	return get_capacity(md->disk);
 469}
 470
 471struct request_queue *dm_get_md_queue(struct mapped_device *md)
 472{
 473	return md->queue;
 474}
 475
 476struct dm_stats *dm_get_stats(struct mapped_device *md)
 477{
 478	return &md->stats;
 479}
 480
 481static int dm_blk_getgeo(struct block_device *bdev, struct hd_geometry *geo)
 482{
 483	struct mapped_device *md = bdev->bd_disk->private_data;
 484
 485	return dm_get_geometry(md, geo);
 486}
 487
 488static int dm_blk_ioctl(struct block_device *bdev, fmode_t mode,
 489			unsigned int cmd, unsigned long arg)
 490{
 491	struct mapped_device *md = bdev->bd_disk->private_data;
 492	int srcu_idx;
 493	struct dm_table *map;
 494	struct dm_target *tgt;
 495	int r = -ENOTTY;
 496
 497retry:
 498	map = dm_get_live_table(md, &srcu_idx);
 499
 500	if (!map || !dm_table_get_size(map))
 501		goto out;
 502
 503	/* We only support devices that have a single target */
 504	if (dm_table_get_num_targets(map) != 1)
 505		goto out;
 506
 507	tgt = dm_table_get_target(map, 0);
 508
 509	if (dm_suspended_md(md)) {
 510		r = -EAGAIN;
 511		goto out;
 512	}
 513
 514	if (tgt->type->ioctl)
 515		r = tgt->type->ioctl(tgt, cmd, arg);
 516
 517out:
 518	dm_put_live_table(md, srcu_idx);
 519
 520	if (r == -ENOTCONN) {
 521		msleep(10);
 522		goto retry;
 523	}
 524
 525	return r;
 526}
 527
 528static struct dm_io *alloc_io(struct mapped_device *md)
 529{
 530	return mempool_alloc(md->io_pool, GFP_NOIO);
 531}
 532
 533static void free_io(struct mapped_device *md, struct dm_io *io)
 534{
 535	mempool_free(io, md->io_pool);
 536}
 537
 538static void free_tio(struct mapped_device *md, struct dm_target_io *tio)
 539{
 540	bio_put(&tio->clone);
 541}
 542
 543static struct dm_rq_target_io *alloc_rq_tio(struct mapped_device *md,
 544					    gfp_t gfp_mask)
 545{
 546	return mempool_alloc(md->io_pool, gfp_mask);
 547}
 548
 549static void free_rq_tio(struct dm_rq_target_io *tio)
 550{
 551	mempool_free(tio, tio->md->io_pool);
 
 
 
 
 
 
 
 
 
 
 552}
 553
 554static int md_in_flight(struct mapped_device *md)
 555{
 556	return atomic_read(&md->pending[READ]) +
 557	       atomic_read(&md->pending[WRITE]);
 558}
 559
 560static void start_io_acct(struct dm_io *io)
 561{
 562	struct mapped_device *md = io->md;
 563	struct bio *bio = io->bio;
 564	int cpu;
 565	int rw = bio_data_dir(bio);
 566
 567	io->start_time = jiffies;
 568
 569	cpu = part_stat_lock();
 570	part_round_stats(cpu, &dm_disk(md)->part0);
 571	part_stat_unlock();
 572	atomic_set(&dm_disk(md)->part0.in_flight[rw],
 573		atomic_inc_return(&md->pending[rw]));
 574
 575	if (unlikely(dm_stats_used(&md->stats)))
 576		dm_stats_account_io(&md->stats, bio->bi_rw, bio->bi_iter.bi_sector,
 577				    bio_sectors(bio), false, 0, &io->stats_aux);
 578}
 579
 580static void end_io_acct(struct dm_io *io)
 581{
 582	struct mapped_device *md = io->md;
 583	struct bio *bio = io->bio;
 584	unsigned long duration = jiffies - io->start_time;
 585	int pending, cpu;
 586	int rw = bio_data_dir(bio);
 587
 588	cpu = part_stat_lock();
 589	part_round_stats(cpu, &dm_disk(md)->part0);
 590	part_stat_add(cpu, &dm_disk(md)->part0, ticks[rw], duration);
 591	part_stat_unlock();
 592
 593	if (unlikely(dm_stats_used(&md->stats)))
 594		dm_stats_account_io(&md->stats, bio->bi_rw, bio->bi_iter.bi_sector,
 595				    bio_sectors(bio), true, duration, &io->stats_aux);
 596
 597	/*
 598	 * After this is decremented the bio must not be touched if it is
 599	 * a flush.
 600	 */
 601	pending = atomic_dec_return(&md->pending[rw]);
 602	atomic_set(&dm_disk(md)->part0.in_flight[rw], pending);
 603	pending += atomic_read(&md->pending[rw^0x1]);
 604
 605	/* nudge anyone waiting on suspend queue */
 606	if (!pending)
 607		wake_up(&md->wait);
 608}
 609
 610/*
 611 * Add the bio to the list of deferred io.
 612 */
 613static void queue_io(struct mapped_device *md, struct bio *bio)
 614{
 615	unsigned long flags;
 616
 617	spin_lock_irqsave(&md->deferred_lock, flags);
 618	bio_list_add(&md->deferred, bio);
 619	spin_unlock_irqrestore(&md->deferred_lock, flags);
 620	queue_work(md->wq, &md->work);
 621}
 622
 623/*
 624 * Everyone (including functions in this file), should use this
 625 * function to access the md->map field, and make sure they call
 626 * dm_put_live_table() when finished.
 627 */
 628struct dm_table *dm_get_live_table(struct mapped_device *md, int *srcu_idx) __acquires(md->io_barrier)
 629{
 630	*srcu_idx = srcu_read_lock(&md->io_barrier);
 631
 632	return srcu_dereference(md->map, &md->io_barrier);
 633}
 634
 635void dm_put_live_table(struct mapped_device *md, int srcu_idx) __releases(md->io_barrier)
 636{
 637	srcu_read_unlock(&md->io_barrier, srcu_idx);
 638}
 639
 640void dm_sync_table(struct mapped_device *md)
 641{
 642	synchronize_srcu(&md->io_barrier);
 643	synchronize_rcu_expedited();
 644}
 645
 646/*
 647 * A fast alternative to dm_get_live_table/dm_put_live_table.
 648 * The caller must not block between these two functions.
 649 */
 650static struct dm_table *dm_get_live_table_fast(struct mapped_device *md) __acquires(RCU)
 651{
 652	rcu_read_lock();
 653	return rcu_dereference(md->map);
 654}
 655
 656static void dm_put_live_table_fast(struct mapped_device *md) __releases(RCU)
 657{
 658	rcu_read_unlock();
 659}
 660
 661/*
 662 * Get the geometry associated with a dm device
 663 */
 664int dm_get_geometry(struct mapped_device *md, struct hd_geometry *geo)
 665{
 666	*geo = md->geometry;
 667
 668	return 0;
 669}
 670
 671/*
 672 * Set the geometry of a device.
 673 */
 674int dm_set_geometry(struct mapped_device *md, struct hd_geometry *geo)
 675{
 676	sector_t sz = (sector_t)geo->cylinders * geo->heads * geo->sectors;
 677
 678	if (geo->start > sz) {
 679		DMWARN("Start sector is beyond the geometry limits.");
 680		return -EINVAL;
 681	}
 682
 683	md->geometry = *geo;
 684
 685	return 0;
 686}
 687
 688/*-----------------------------------------------------------------
 689 * CRUD START:
 690 *   A more elegant soln is in the works that uses the queue
 691 *   merge fn, unfortunately there are a couple of changes to
 692 *   the block layer that I want to make for this.  So in the
 693 *   interests of getting something for people to use I give
 694 *   you this clearly demarcated crap.
 695 *---------------------------------------------------------------*/
 696
 697static int __noflush_suspending(struct mapped_device *md)
 698{
 699	return test_bit(DMF_NOFLUSH_SUSPENDING, &md->flags);
 700}
 701
 702/*
 703 * Decrements the number of outstanding ios that a bio has been
 704 * cloned into, completing the original io if necc.
 705 */
 706static void dec_pending(struct dm_io *io, int error)
 707{
 708	unsigned long flags;
 709	int io_error;
 710	struct bio *bio;
 711	struct mapped_device *md = io->md;
 712
 713	/* Push-back supersedes any I/O errors */
 714	if (unlikely(error)) {
 715		spin_lock_irqsave(&io->endio_lock, flags);
 716		if (!(io->error > 0 && __noflush_suspending(md)))
 717			io->error = error;
 718		spin_unlock_irqrestore(&io->endio_lock, flags);
 719	}
 720
 721	if (atomic_dec_and_test(&io->io_count)) {
 722		if (io->error == DM_ENDIO_REQUEUE) {
 723			/*
 724			 * Target requested pushing back the I/O.
 725			 */
 726			spin_lock_irqsave(&md->deferred_lock, flags);
 727			if (__noflush_suspending(md))
 728				bio_list_add_head(&md->deferred, io->bio);
 729			else
 730				/* noflush suspend was interrupted. */
 731				io->error = -EIO;
 732			spin_unlock_irqrestore(&md->deferred_lock, flags);
 733		}
 734
 735		io_error = io->error;
 736		bio = io->bio;
 737		end_io_acct(io);
 738		free_io(md, io);
 739
 740		if (io_error == DM_ENDIO_REQUEUE)
 741			return;
 742
 743		if ((bio->bi_rw & REQ_FLUSH) && bio->bi_iter.bi_size) {
 744			/*
 745			 * Preflush done for flush with data, reissue
 746			 * without REQ_FLUSH.
 747			 */
 748			bio->bi_rw &= ~REQ_FLUSH;
 749			queue_io(md, bio);
 750		} else {
 751			/* done with normal IO or empty flush */
 752			trace_block_bio_complete(md->queue, bio, io_error);
 753			bio_endio(bio, io_error);
 754		}
 755	}
 756}
 757
 758static void clone_endio(struct bio *bio, int error)
 759{
 760	int r = 0;
 761	struct dm_target_io *tio = container_of(bio, struct dm_target_io, clone);
 762	struct dm_io *io = tio->io;
 763	struct mapped_device *md = tio->io->md;
 764	dm_endio_fn endio = tio->ti->type->end_io;
 765
 766	if (!bio_flagged(bio, BIO_UPTODATE) && !error)
 767		error = -EIO;
 768
 769	if (endio) {
 770		r = endio(tio->ti, bio, error);
 771		if (r < 0 || r == DM_ENDIO_REQUEUE)
 772			/*
 773			 * error and requeue request are handled
 774			 * in dec_pending().
 775			 */
 776			error = r;
 777		else if (r == DM_ENDIO_INCOMPLETE)
 778			/* The target will handle the io */
 779			return;
 780		else if (r) {
 781			DMWARN("unimplemented target endio return value: %d", r);
 782			BUG();
 783		}
 784	}
 785
 
 
 
 
 
 786	free_tio(md, tio);
 
 787	dec_pending(io, error);
 788}
 789
 790/*
 791 * Partial completion handling for request-based dm
 792 */
 793static void end_clone_bio(struct bio *clone, int error)
 794{
 795	struct dm_rq_clone_bio_info *info =
 796		container_of(clone, struct dm_rq_clone_bio_info, clone);
 797	struct dm_rq_target_io *tio = info->tio;
 798	struct bio *bio = info->orig;
 799	unsigned int nr_bytes = info->orig->bi_iter.bi_size;
 800
 801	bio_put(clone);
 802
 803	if (tio->error)
 804		/*
 805		 * An error has already been detected on the request.
 806		 * Once error occurred, just let clone->end_io() handle
 807		 * the remainder.
 808		 */
 809		return;
 810	else if (error) {
 811		/*
 812		 * Don't notice the error to the upper layer yet.
 813		 * The error handling decision is made by the target driver,
 814		 * when the request is completed.
 815		 */
 816		tio->error = error;
 817		return;
 818	}
 819
 820	/*
 821	 * I/O for the bio successfully completed.
 822	 * Notice the data completion to the upper layer.
 823	 */
 824
 825	/*
 826	 * bios are processed from the head of the list.
 827	 * So the completing bio should always be rq->bio.
 828	 * If it's not, something wrong is happening.
 829	 */
 830	if (tio->orig->bio != bio)
 831		DMERR("bio completion is going in the middle of the request");
 832
 833	/*
 834	 * Update the original request.
 835	 * Do not use blk_end_request() here, because it may complete
 836	 * the original request before the clone, and break the ordering.
 837	 */
 838	blk_update_request(tio->orig, 0, nr_bytes);
 839}
 840
 841/*
 842 * Don't touch any member of the md after calling this function because
 843 * the md may be freed in dm_put() at the end of this function.
 844 * Or do dm_get() before calling this function and dm_put() later.
 845 */
 846static void rq_completed(struct mapped_device *md, int rw, int run_queue)
 847{
 848	atomic_dec(&md->pending[rw]);
 849
 850	/* nudge anyone waiting on suspend queue */
 851	if (!md_in_flight(md))
 852		wake_up(&md->wait);
 853
 854	/*
 855	 * Run this off this callpath, as drivers could invoke end_io while
 856	 * inside their request_fn (and holding the queue lock). Calling
 857	 * back into ->request_fn() could deadlock attempting to grab the
 858	 * queue lock again.
 859	 */
 860	if (run_queue)
 861		blk_run_queue_async(md->queue);
 862
 863	/*
 864	 * dm_put() must be at the end of this function. See the comment above
 865	 */
 866	dm_put(md);
 867}
 868
 869static void free_rq_clone(struct request *clone)
 870{
 871	struct dm_rq_target_io *tio = clone->end_io_data;
 872
 873	blk_rq_unprep_clone(clone);
 874	free_rq_tio(tio);
 875}
 876
 877/*
 878 * Complete the clone and the original request.
 879 * Must be called without queue lock.
 880 */
 881static void dm_end_request(struct request *clone, int error)
 882{
 883	int rw = rq_data_dir(clone);
 884	struct dm_rq_target_io *tio = clone->end_io_data;
 885	struct mapped_device *md = tio->md;
 886	struct request *rq = tio->orig;
 887
 888	if (rq->cmd_type == REQ_TYPE_BLOCK_PC) {
 889		rq->errors = clone->errors;
 890		rq->resid_len = clone->resid_len;
 891
 892		if (rq->sense)
 893			/*
 894			 * We are using the sense buffer of the original
 895			 * request.
 896			 * So setting the length of the sense data is enough.
 897			 */
 898			rq->sense_len = clone->sense_len;
 899	}
 900
 901	free_rq_clone(clone);
 902	blk_end_request_all(rq, error);
 903	rq_completed(md, rw, true);
 904}
 905
 906static void dm_unprep_request(struct request *rq)
 907{
 908	struct request *clone = rq->special;
 909
 910	rq->special = NULL;
 911	rq->cmd_flags &= ~REQ_DONTPREP;
 912
 913	free_rq_clone(clone);
 914}
 915
 916/*
 917 * Requeue the original request of a clone.
 918 */
 919void dm_requeue_unmapped_request(struct request *clone)
 920{
 921	int rw = rq_data_dir(clone);
 922	struct dm_rq_target_io *tio = clone->end_io_data;
 923	struct mapped_device *md = tio->md;
 924	struct request *rq = tio->orig;
 925	struct request_queue *q = rq->q;
 926	unsigned long flags;
 927
 928	dm_unprep_request(rq);
 929
 930	spin_lock_irqsave(q->queue_lock, flags);
 931	blk_requeue_request(q, rq);
 932	spin_unlock_irqrestore(q->queue_lock, flags);
 933
 934	rq_completed(md, rw, 0);
 935}
 936EXPORT_SYMBOL_GPL(dm_requeue_unmapped_request);
 937
 938static void __stop_queue(struct request_queue *q)
 939{
 940	blk_stop_queue(q);
 941}
 942
 943static void stop_queue(struct request_queue *q)
 944{
 945	unsigned long flags;
 946
 947	spin_lock_irqsave(q->queue_lock, flags);
 948	__stop_queue(q);
 949	spin_unlock_irqrestore(q->queue_lock, flags);
 950}
 951
 952static void __start_queue(struct request_queue *q)
 953{
 954	if (blk_queue_stopped(q))
 955		blk_start_queue(q);
 956}
 957
 958static void start_queue(struct request_queue *q)
 959{
 960	unsigned long flags;
 961
 962	spin_lock_irqsave(q->queue_lock, flags);
 963	__start_queue(q);
 964	spin_unlock_irqrestore(q->queue_lock, flags);
 965}
 966
 967static void dm_done(struct request *clone, int error, bool mapped)
 968{
 969	int r = error;
 970	struct dm_rq_target_io *tio = clone->end_io_data;
 971	dm_request_endio_fn rq_end_io = NULL;
 972
 973	if (tio->ti) {
 974		rq_end_io = tio->ti->type->rq_end_io;
 975
 976		if (mapped && rq_end_io)
 977			r = rq_end_io(tio->ti, clone, error, &tio->info);
 978	}
 979
 980	if (r <= 0)
 981		/* The target wants to complete the I/O */
 982		dm_end_request(clone, r);
 983	else if (r == DM_ENDIO_INCOMPLETE)
 984		/* The target will handle the I/O */
 985		return;
 986	else if (r == DM_ENDIO_REQUEUE)
 987		/* The target wants to requeue the I/O */
 988		dm_requeue_unmapped_request(clone);
 989	else {
 990		DMWARN("unimplemented target endio return value: %d", r);
 991		BUG();
 992	}
 993}
 994
 995/*
 996 * Request completion handler for request-based dm
 997 */
 998static void dm_softirq_done(struct request *rq)
 999{
1000	bool mapped = true;
1001	struct request *clone = rq->completion_data;
1002	struct dm_rq_target_io *tio = clone->end_io_data;
1003
1004	if (rq->cmd_flags & REQ_FAILED)
1005		mapped = false;
1006
1007	dm_done(clone, tio->error, mapped);
1008}
1009
1010/*
1011 * Complete the clone and the original request with the error status
1012 * through softirq context.
1013 */
1014static void dm_complete_request(struct request *clone, int error)
1015{
1016	struct dm_rq_target_io *tio = clone->end_io_data;
1017	struct request *rq = tio->orig;
1018
1019	tio->error = error;
1020	rq->completion_data = clone;
1021	blk_complete_request(rq);
1022}
1023
1024/*
1025 * Complete the not-mapped clone and the original request with the error status
1026 * through softirq context.
1027 * Target's rq_end_io() function isn't called.
1028 * This may be used when the target's map_rq() function fails.
1029 */
1030void dm_kill_unmapped_request(struct request *clone, int error)
1031{
1032	struct dm_rq_target_io *tio = clone->end_io_data;
1033	struct request *rq = tio->orig;
1034
1035	rq->cmd_flags |= REQ_FAILED;
1036	dm_complete_request(clone, error);
1037}
1038EXPORT_SYMBOL_GPL(dm_kill_unmapped_request);
1039
1040/*
1041 * Called with the queue lock held
1042 */
1043static void end_clone_request(struct request *clone, int error)
1044{
1045	/*
1046	 * For just cleaning up the information of the queue in which
1047	 * the clone was dispatched.
1048	 * The clone is *NOT* freed actually here because it is alloced from
1049	 * dm own mempool and REQ_ALLOCED isn't set in clone->cmd_flags.
1050	 */
1051	__blk_put_request(clone->q, clone);
1052
1053	/*
1054	 * Actual request completion is done in a softirq context which doesn't
1055	 * hold the queue lock.  Otherwise, deadlock could occur because:
1056	 *     - another request may be submitted by the upper level driver
1057	 *       of the stacking during the completion
1058	 *     - the submission which requires queue lock may be done
1059	 *       against this queue
1060	 */
1061	dm_complete_request(clone, error);
1062}
1063
1064/*
1065 * Return maximum size of I/O possible at the supplied sector up to the current
1066 * target boundary.
1067 */
1068static sector_t max_io_len_target_boundary(sector_t sector, struct dm_target *ti)
1069{
1070	sector_t target_offset = dm_target_offset(ti, sector);
1071
1072	return ti->len - target_offset;
1073}
1074
1075static sector_t max_io_len(sector_t sector, struct dm_target *ti)
1076{
1077	sector_t len = max_io_len_target_boundary(sector, ti);
1078	sector_t offset, max_len;
1079
1080	/*
1081	 * Does the target need to split even further?
1082	 */
1083	if (ti->max_io_len) {
1084		offset = dm_target_offset(ti, sector);
1085		if (unlikely(ti->max_io_len & (ti->max_io_len - 1)))
1086			max_len = sector_div(offset, ti->max_io_len);
1087		else
1088			max_len = offset & (ti->max_io_len - 1);
1089		max_len = ti->max_io_len - max_len;
1090
1091		if (len > max_len)
1092			len = max_len;
1093	}
1094
1095	return len;
1096}
1097
1098int dm_set_target_max_io_len(struct dm_target *ti, sector_t len)
1099{
1100	if (len > UINT_MAX) {
1101		DMERR("Specified maximum size of target IO (%llu) exceeds limit (%u)",
1102		      (unsigned long long)len, UINT_MAX);
1103		ti->error = "Maximum size of target IO is too large";
1104		return -EINVAL;
1105	}
1106
1107	ti->max_io_len = (uint32_t) len;
1108
1109	return 0;
1110}
1111EXPORT_SYMBOL_GPL(dm_set_target_max_io_len);
1112
1113static void __map_bio(struct dm_target_io *tio)
1114{
1115	int r;
1116	sector_t sector;
1117	struct mapped_device *md;
1118	struct bio *clone = &tio->clone;
1119	struct dm_target *ti = tio->ti;
1120
1121	clone->bi_end_io = clone_endio;
 
1122
1123	/*
1124	 * Map the clone.  If r == 0 we don't need to do
1125	 * anything, the target has assumed ownership of
1126	 * this io.
1127	 */
1128	atomic_inc(&tio->io->io_count);
1129	sector = clone->bi_iter.bi_sector;
1130	r = ti->type->map(ti, clone);
1131	if (r == DM_MAPIO_REMAPPED) {
1132		/* the bio has been remapped so dispatch it */
1133
1134		trace_block_bio_remap(bdev_get_queue(clone->bi_bdev), clone,
1135				      tio->io->bio->bi_bdev->bd_dev, sector);
1136
1137		generic_make_request(clone);
1138	} else if (r < 0 || r == DM_MAPIO_REQUEUE) {
1139		/* error the io and bail out, or requeue it if needed */
1140		md = tio->io->md;
1141		dec_pending(tio->io, r);
 
 
 
 
 
1142		free_tio(md, tio);
1143	} else if (r) {
1144		DMWARN("unimplemented target map return value: %d", r);
1145		BUG();
1146	}
1147}
1148
1149struct clone_info {
1150	struct mapped_device *md;
1151	struct dm_table *map;
1152	struct bio *bio;
1153	struct dm_io *io;
1154	sector_t sector;
1155	sector_t sector_count;
 
1156};
1157
1158static void bio_setup_sector(struct bio *bio, sector_t sector, sector_t len)
1159{
1160	bio->bi_iter.bi_sector = sector;
1161	bio->bi_iter.bi_size = to_bytes(len);
 
1162}
1163
1164/*
1165 * Creates a bio that consists of range of complete bvecs.
1166 */
1167static void clone_bio(struct dm_target_io *tio, struct bio *bio,
1168		      sector_t sector, unsigned len)
 
1169{
1170	struct bio *clone = &tio->clone;
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
1171
1172	__bio_clone_fast(clone, bio);
 
1173
1174	if (bio_integrity(bio))
1175		bio_integrity_clone(clone, bio, GFP_NOIO);
 
 
 
 
 
 
1176
1177	bio_advance(clone, to_bytes(sector - clone->bi_iter.bi_sector));
1178	clone->bi_iter.bi_size = to_bytes(len);
 
 
 
 
 
 
 
 
 
 
 
 
 
 
1179
1180	if (bio_integrity(bio))
1181		bio_integrity_trim(clone, 0, len);
1182}
1183
1184static struct dm_target_io *alloc_tio(struct clone_info *ci,
1185				      struct dm_target *ti, int nr_iovecs,
1186				      unsigned target_bio_nr)
1187{
1188	struct dm_target_io *tio;
1189	struct bio *clone;
1190
1191	clone = bio_alloc_bioset(GFP_NOIO, nr_iovecs, ci->md->bs);
1192	tio = container_of(clone, struct dm_target_io, clone);
1193
1194	tio->io = ci->io;
1195	tio->ti = ti;
1196	tio->target_bio_nr = target_bio_nr;
1197
1198	return tio;
1199}
1200
1201static void __clone_and_map_simple_bio(struct clone_info *ci,
1202				       struct dm_target *ti,
1203				       unsigned target_bio_nr, sector_t len)
1204{
1205	struct dm_target_io *tio = alloc_tio(ci, ti, ci->bio->bi_max_vecs, target_bio_nr);
1206	struct bio *clone = &tio->clone;
 
 
1207
1208	/*
1209	 * Discard requests require the bio's inline iovecs be initialized.
1210	 * ci->bio->bi_max_vecs is BIO_INLINE_VECS anyway, for both flush
1211	 * and discard, so no need for concern about wasted bvec allocations.
1212	 */
1213	 __bio_clone_fast(clone, ci->bio);
1214	if (len)
1215		bio_setup_sector(clone, ci->sector, len);
 
 
 
 
1216
1217	__map_bio(tio);
1218}
1219
1220static void __send_duplicate_bios(struct clone_info *ci, struct dm_target *ti,
1221				  unsigned num_bios, sector_t len)
1222{
1223	unsigned target_bio_nr;
1224
1225	for (target_bio_nr = 0; target_bio_nr < num_bios; target_bio_nr++)
1226		__clone_and_map_simple_bio(ci, ti, target_bio_nr, len);
1227}
1228
1229static int __send_empty_flush(struct clone_info *ci)
1230{
1231	unsigned target_nr = 0;
1232	struct dm_target *ti;
1233
1234	BUG_ON(bio_has_data(ci->bio));
1235	while ((ti = dm_table_get_target(ci->map, target_nr++)))
1236		__send_duplicate_bios(ci, ti, ti->num_flush_bios, 0);
1237
1238	return 0;
1239}
1240
1241static void __clone_and_map_data_bio(struct clone_info *ci, struct dm_target *ti,
1242				     sector_t sector, unsigned len)
 
 
1243{
1244	struct bio *bio = ci->bio;
1245	struct dm_target_io *tio;
1246	unsigned target_bio_nr;
1247	unsigned num_target_bios = 1;
1248
1249	/*
1250	 * Does the target want to receive duplicate copies of the bio?
1251	 */
1252	if (bio_data_dir(bio) == WRITE && ti->num_write_bios)
1253		num_target_bios = ti->num_write_bios(ti, bio);
1254
1255	for (target_bio_nr = 0; target_bio_nr < num_target_bios; target_bio_nr++) {
1256		tio = alloc_tio(ci, ti, 0, target_bio_nr);
1257		clone_bio(tio, bio, sector, len);
1258		__map_bio(tio);
1259	}
1260}
1261
1262typedef unsigned (*get_num_bios_fn)(struct dm_target *ti);
1263
1264static unsigned get_num_discard_bios(struct dm_target *ti)
1265{
1266	return ti->num_discard_bios;
1267}
1268
1269static unsigned get_num_write_same_bios(struct dm_target *ti)
1270{
1271	return ti->num_write_same_bios;
1272}
1273
1274typedef bool (*is_split_required_fn)(struct dm_target *ti);
1275
1276static bool is_split_required_for_discard(struct dm_target *ti)
1277{
1278	return ti->split_discard_bios;
1279}
1280
1281static int __send_changing_extent_only(struct clone_info *ci,
1282				       get_num_bios_fn get_num_bios,
1283				       is_split_required_fn is_split_required)
1284{
1285	struct dm_target *ti;
1286	sector_t len;
1287	unsigned num_bios;
1288
1289	do {
1290		ti = dm_table_find_target(ci->map, ci->sector);
1291		if (!dm_target_is_valid(ti))
1292			return -EIO;
1293
1294		/*
1295		 * Even though the device advertised support for this type of
1296		 * request, that does not mean every target supports it, and
1297		 * reconfiguration might also have changed that since the
1298		 * check was performed.
1299		 */
1300		num_bios = get_num_bios ? get_num_bios(ti) : 0;
1301		if (!num_bios)
1302			return -EOPNOTSUPP;
1303
1304		if (is_split_required && !is_split_required(ti))
1305			len = min(ci->sector_count, max_io_len_target_boundary(ci->sector, ti));
1306		else
1307			len = min(ci->sector_count, max_io_len(ci->sector, ti));
1308
1309		__send_duplicate_bios(ci, ti, num_bios, len);
1310
1311		ci->sector += len;
1312	} while (ci->sector_count -= len);
1313
1314	return 0;
1315}
1316
1317static int __send_discard(struct clone_info *ci)
1318{
1319	return __send_changing_extent_only(ci, get_num_discard_bios,
1320					   is_split_required_for_discard);
1321}
1322
1323static int __send_write_same(struct clone_info *ci)
1324{
1325	return __send_changing_extent_only(ci, get_num_write_same_bios, NULL);
1326}
1327
1328/*
1329 * Select the correct strategy for processing a non-flush bio.
1330 */
1331static int __split_and_process_non_flush(struct clone_info *ci)
1332{
1333	struct bio *bio = ci->bio;
1334	struct dm_target *ti;
1335	unsigned len;
 
1336
1337	if (unlikely(bio->bi_rw & REQ_DISCARD))
1338		return __send_discard(ci);
1339	else if (unlikely(bio->bi_rw & REQ_WRITE_SAME))
1340		return __send_write_same(ci);
1341
1342	ti = dm_table_find_target(ci->map, ci->sector);
1343	if (!dm_target_is_valid(ti))
1344		return -EIO;
1345
1346	len = min_t(sector_t, max_io_len(ci->sector, ti), ci->sector_count);
1347
1348	__clone_and_map_data_bio(ci, ti, ci->sector, len);
 
 
 
 
 
1349
1350	ci->sector += len;
1351	ci->sector_count -= len;
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
1352
1353	return 0;
1354}
1355
1356/*
1357 * Entry point to split a bio into clones and submit them to the targets.
1358 */
1359static void __split_and_process_bio(struct mapped_device *md,
1360				    struct dm_table *map, struct bio *bio)
1361{
1362	struct clone_info ci;
1363	int error = 0;
1364
1365	if (unlikely(!map)) {
 
1366		bio_io_error(bio);
1367		return;
1368	}
1369
1370	ci.map = map;
1371	ci.md = md;
1372	ci.io = alloc_io(md);
1373	ci.io->error = 0;
1374	atomic_set(&ci.io->io_count, 1);
1375	ci.io->bio = bio;
1376	ci.io->md = md;
1377	spin_lock_init(&ci.io->endio_lock);
1378	ci.sector = bio->bi_iter.bi_sector;
 
1379
1380	start_io_acct(ci.io);
1381
1382	if (bio->bi_rw & REQ_FLUSH) {
1383		ci.bio = &ci.md->flush_bio;
1384		ci.sector_count = 0;
1385		error = __send_empty_flush(&ci);
1386		/* dec_pending submits any data associated with flush */
1387	} else {
1388		ci.bio = bio;
1389		ci.sector_count = bio_sectors(bio);
1390		while (ci.sector_count && !error)
1391			error = __split_and_process_non_flush(&ci);
1392	}
1393
1394	/* drop the extra reference count */
1395	dec_pending(ci.io, error);
 
1396}
1397/*-----------------------------------------------------------------
1398 * CRUD END
1399 *---------------------------------------------------------------*/
1400
1401static int dm_merge_bvec(struct request_queue *q,
1402			 struct bvec_merge_data *bvm,
1403			 struct bio_vec *biovec)
1404{
1405	struct mapped_device *md = q->queuedata;
1406	struct dm_table *map = dm_get_live_table_fast(md);
1407	struct dm_target *ti;
1408	sector_t max_sectors;
1409	int max_size = 0;
1410
1411	if (unlikely(!map))
1412		goto out;
1413
1414	ti = dm_table_find_target(map, bvm->bi_sector);
1415	if (!dm_target_is_valid(ti))
1416		goto out;
1417
1418	/*
1419	 * Find maximum amount of I/O that won't need splitting
1420	 */
1421	max_sectors = min(max_io_len(bvm->bi_sector, ti),
1422			  (sector_t) BIO_MAX_SECTORS);
1423	max_size = (max_sectors << SECTOR_SHIFT) - bvm->bi_size;
1424	if (max_size < 0)
1425		max_size = 0;
1426
1427	/*
1428	 * merge_bvec_fn() returns number of bytes
1429	 * it can accept at this offset
1430	 * max is precomputed maximal io size
1431	 */
1432	if (max_size && ti->type->merge)
1433		max_size = ti->type->merge(ti, bvm, biovec, max_size);
1434	/*
1435	 * If the target doesn't support merge method and some of the devices
1436	 * provided their merge_bvec method (we know this by looking at
1437	 * queue_max_hw_sectors), then we can't allow bios with multiple vector
1438	 * entries.  So always set max_size to 0, and the code below allows
1439	 * just one page.
1440	 */
1441	else if (queue_max_hw_sectors(q) <= PAGE_SIZE >> 9)
1442
1443		max_size = 0;
1444
 
 
 
1445out:
1446	dm_put_live_table_fast(md);
1447	/*
1448	 * Always allow an entire first page
1449	 */
1450	if (max_size <= biovec->bv_len && !(bvm->bi_size >> SECTOR_SHIFT))
1451		max_size = biovec->bv_len;
1452
1453	return max_size;
1454}
1455
1456/*
1457 * The request function that just remaps the bio built up by
1458 * dm_merge_bvec.
1459 */
1460static void _dm_request(struct request_queue *q, struct bio *bio)
1461{
1462	int rw = bio_data_dir(bio);
1463	struct mapped_device *md = q->queuedata;
1464	int cpu;
1465	int srcu_idx;
1466	struct dm_table *map;
1467
1468	map = dm_get_live_table(md, &srcu_idx);
1469
1470	cpu = part_stat_lock();
1471	part_stat_inc(cpu, &dm_disk(md)->part0, ios[rw]);
1472	part_stat_add(cpu, &dm_disk(md)->part0, sectors[rw], bio_sectors(bio));
1473	part_stat_unlock();
1474
1475	/* if we're suspended, we have to queue this io for later */
1476	if (unlikely(test_bit(DMF_BLOCK_IO_FOR_SUSPEND, &md->flags))) {
1477		dm_put_live_table(md, srcu_idx);
1478
1479		if (bio_rw(bio) != READA)
1480			queue_io(md, bio);
1481		else
1482			bio_io_error(bio);
1483		return;
1484	}
1485
1486	__split_and_process_bio(md, map, bio);
1487	dm_put_live_table(md, srcu_idx);
1488	return;
 
 
 
 
 
 
 
1489}
1490
1491int dm_request_based(struct mapped_device *md)
1492{
1493	return blk_queue_stackable(md->queue);
1494}
1495
1496static void dm_request(struct request_queue *q, struct bio *bio)
1497{
1498	struct mapped_device *md = q->queuedata;
1499
1500	if (dm_request_based(md))
1501		blk_queue_bio(q, bio);
1502	else
1503		_dm_request(q, bio);
1504}
1505
1506void dm_dispatch_request(struct request *rq)
1507{
1508	int r;
1509
1510	if (blk_queue_io_stat(rq->q))
1511		rq->cmd_flags |= REQ_IO_STAT;
1512
1513	rq->start_time = jiffies;
1514	r = blk_insert_cloned_request(rq->q, rq);
1515	if (r)
1516		dm_complete_request(rq, r);
1517}
1518EXPORT_SYMBOL_GPL(dm_dispatch_request);
1519
 
 
 
 
 
 
 
 
 
1520static int dm_rq_bio_constructor(struct bio *bio, struct bio *bio_orig,
1521				 void *data)
1522{
1523	struct dm_rq_target_io *tio = data;
1524	struct dm_rq_clone_bio_info *info =
1525		container_of(bio, struct dm_rq_clone_bio_info, clone);
 
 
 
1526
1527	info->orig = bio_orig;
1528	info->tio = tio;
1529	bio->bi_end_io = end_clone_bio;
 
 
1530
1531	return 0;
1532}
1533
1534static int setup_clone(struct request *clone, struct request *rq,
1535		       struct dm_rq_target_io *tio)
1536{
1537	int r;
1538
1539	r = blk_rq_prep_clone(clone, rq, tio->md->bs, GFP_ATOMIC,
1540			      dm_rq_bio_constructor, tio);
1541	if (r)
1542		return r;
1543
1544	clone->cmd = rq->cmd;
1545	clone->cmd_len = rq->cmd_len;
1546	clone->sense = rq->sense;
1547	clone->buffer = rq->buffer;
1548	clone->end_io = end_clone_request;
1549	clone->end_io_data = tio;
1550
1551	return 0;
1552}
1553
1554static struct request *clone_rq(struct request *rq, struct mapped_device *md,
1555				gfp_t gfp_mask)
1556{
1557	struct request *clone;
1558	struct dm_rq_target_io *tio;
1559
1560	tio = alloc_rq_tio(md, gfp_mask);
1561	if (!tio)
1562		return NULL;
1563
1564	tio->md = md;
1565	tio->ti = NULL;
1566	tio->orig = rq;
1567	tio->error = 0;
1568	memset(&tio->info, 0, sizeof(tio->info));
1569
1570	clone = &tio->clone;
1571	if (setup_clone(clone, rq, tio)) {
1572		/* -ENOMEM */
1573		free_rq_tio(tio);
1574		return NULL;
1575	}
1576
1577	return clone;
1578}
1579
1580/*
1581 * Called with the queue lock held.
1582 */
1583static int dm_prep_fn(struct request_queue *q, struct request *rq)
1584{
1585	struct mapped_device *md = q->queuedata;
1586	struct request *clone;
1587
1588	if (unlikely(rq->special)) {
1589		DMWARN("Already has something in rq->special.");
1590		return BLKPREP_KILL;
1591	}
1592
1593	clone = clone_rq(rq, md, GFP_ATOMIC);
1594	if (!clone)
1595		return BLKPREP_DEFER;
1596
1597	rq->special = clone;
1598	rq->cmd_flags |= REQ_DONTPREP;
1599
1600	return BLKPREP_OK;
1601}
1602
1603/*
1604 * Returns:
1605 * 0  : the request has been processed (not requeued)
1606 * !0 : the request has been requeued
1607 */
1608static int map_request(struct dm_target *ti, struct request *clone,
1609		       struct mapped_device *md)
1610{
1611	int r, requeued = 0;
1612	struct dm_rq_target_io *tio = clone->end_io_data;
1613
 
 
 
 
 
 
 
 
 
1614	tio->ti = ti;
1615	r = ti->type->map_rq(ti, clone, &tio->info);
1616	switch (r) {
1617	case DM_MAPIO_SUBMITTED:
1618		/* The target has taken the I/O to submit by itself later */
1619		break;
1620	case DM_MAPIO_REMAPPED:
1621		/* The target has remapped the I/O so dispatch it */
1622		trace_block_rq_remap(clone->q, clone, disk_devt(dm_disk(md)),
1623				     blk_rq_pos(tio->orig));
1624		dm_dispatch_request(clone);
1625		break;
1626	case DM_MAPIO_REQUEUE:
1627		/* The target wants to requeue the I/O */
1628		dm_requeue_unmapped_request(clone);
1629		requeued = 1;
1630		break;
1631	default:
1632		if (r > 0) {
1633			DMWARN("unimplemented target map return value: %d", r);
1634			BUG();
1635		}
1636
1637		/* The target wants to complete the I/O */
1638		dm_kill_unmapped_request(clone, r);
1639		break;
1640	}
1641
1642	return requeued;
1643}
1644
1645static struct request *dm_start_request(struct mapped_device *md, struct request *orig)
1646{
1647	struct request *clone;
1648
1649	blk_start_request(orig);
1650	clone = orig->special;
1651	atomic_inc(&md->pending[rq_data_dir(clone)]);
1652
1653	/*
1654	 * Hold the md reference here for the in-flight I/O.
1655	 * We can't rely on the reference count by device opener,
1656	 * because the device may be closed during the request completion
1657	 * when all bios are completed.
1658	 * See the comment in rq_completed() too.
1659	 */
1660	dm_get(md);
1661
1662	return clone;
1663}
1664
1665/*
1666 * q->request_fn for request-based dm.
1667 * Called with the queue lock held.
1668 */
1669static void dm_request_fn(struct request_queue *q)
1670{
1671	struct mapped_device *md = q->queuedata;
1672	int srcu_idx;
1673	struct dm_table *map = dm_get_live_table(md, &srcu_idx);
1674	struct dm_target *ti;
1675	struct request *rq, *clone;
1676	sector_t pos;
1677
1678	/*
1679	 * For suspend, check blk_queue_stopped() and increment
1680	 * ->pending within a single queue_lock not to increment the
1681	 * number of in-flight I/Os after the queue is stopped in
1682	 * dm_suspend().
1683	 */
1684	while (!blk_queue_stopped(q)) {
1685		rq = blk_peek_request(q);
1686		if (!rq)
1687			goto delay_and_out;
1688
1689		/* always use block 0 to find the target for flushes for now */
1690		pos = 0;
1691		if (!(rq->cmd_flags & REQ_FLUSH))
1692			pos = blk_rq_pos(rq);
1693
1694		ti = dm_table_find_target(map, pos);
1695		if (!dm_target_is_valid(ti)) {
1696			/*
1697			 * Must perform setup, that dm_done() requires,
1698			 * before calling dm_kill_unmapped_request
1699			 */
1700			DMERR_LIMIT("request attempted access beyond the end of device");
1701			clone = dm_start_request(md, rq);
1702			dm_kill_unmapped_request(clone, -EIO);
1703			continue;
1704		}
1705
1706		if (ti->type->busy && ti->type->busy(ti))
1707			goto delay_and_out;
1708
1709		clone = dm_start_request(md, rq);
 
 
1710
1711		spin_unlock(q->queue_lock);
1712		if (map_request(ti, clone, md))
1713			goto requeued;
1714
1715		BUG_ON(!irqs_disabled());
1716		spin_lock(q->queue_lock);
1717	}
1718
1719	goto out;
1720
1721requeued:
1722	BUG_ON(!irqs_disabled());
1723	spin_lock(q->queue_lock);
1724
1725delay_and_out:
1726	blk_delay_queue(q, HZ / 10);
1727out:
1728	dm_put_live_table(md, srcu_idx);
 
 
1729}
1730
1731int dm_underlying_device_busy(struct request_queue *q)
1732{
1733	return blk_lld_busy(q);
1734}
1735EXPORT_SYMBOL_GPL(dm_underlying_device_busy);
1736
1737static int dm_lld_busy(struct request_queue *q)
1738{
1739	int r;
1740	struct mapped_device *md = q->queuedata;
1741	struct dm_table *map = dm_get_live_table_fast(md);
1742
1743	if (!map || test_bit(DMF_BLOCK_IO_FOR_SUSPEND, &md->flags))
1744		r = 1;
1745	else
1746		r = dm_table_any_busy_target(map);
1747
1748	dm_put_live_table_fast(md);
1749
1750	return r;
1751}
1752
1753static int dm_any_congested(void *congested_data, int bdi_bits)
1754{
1755	int r = bdi_bits;
1756	struct mapped_device *md = congested_data;
1757	struct dm_table *map;
1758
1759	if (!test_bit(DMF_BLOCK_IO_FOR_SUSPEND, &md->flags)) {
1760		map = dm_get_live_table_fast(md);
1761		if (map) {
1762			/*
1763			 * Request-based dm cares about only own queue for
1764			 * the query about congestion status of request_queue
1765			 */
1766			if (dm_request_based(md))
1767				r = md->queue->backing_dev_info.state &
1768				    bdi_bits;
1769			else
1770				r = dm_table_any_congested(map, bdi_bits);
 
 
1771		}
1772		dm_put_live_table_fast(md);
1773	}
1774
1775	return r;
1776}
1777
1778/*-----------------------------------------------------------------
1779 * An IDR is used to keep track of allocated minor numbers.
1780 *---------------------------------------------------------------*/
1781static void free_minor(int minor)
1782{
1783	spin_lock(&_minor_lock);
1784	idr_remove(&_minor_idr, minor);
1785	spin_unlock(&_minor_lock);
1786}
1787
1788/*
1789 * See if the device with a specific minor # is free.
1790 */
1791static int specific_minor(int minor)
1792{
1793	int r;
1794
1795	if (minor >= (1 << MINORBITS))
1796		return -EINVAL;
1797
1798	idr_preload(GFP_KERNEL);
 
 
 
1799	spin_lock(&_minor_lock);
1800
1801	r = idr_alloc(&_minor_idr, MINOR_ALLOCED, minor, minor + 1, GFP_NOWAIT);
 
 
 
 
 
 
 
1802
 
 
 
 
 
 
 
1803	spin_unlock(&_minor_lock);
1804	idr_preload_end();
1805	if (r < 0)
1806		return r == -ENOSPC ? -EBUSY : r;
1807	return 0;
1808}
1809
1810static int next_free_minor(int *minor)
1811{
1812	int r;
 
 
 
 
1813
1814	idr_preload(GFP_KERNEL);
1815	spin_lock(&_minor_lock);
1816
1817	r = idr_alloc(&_minor_idr, MINOR_ALLOCED, 0, 1 << MINORBITS, GFP_NOWAIT);
 
 
 
 
 
 
 
 
 
 
1818
 
1819	spin_unlock(&_minor_lock);
1820	idr_preload_end();
1821	if (r < 0)
1822		return r;
1823	*minor = r;
1824	return 0;
1825}
1826
1827static const struct block_device_operations dm_blk_dops;
1828
1829static void dm_wq_work(struct work_struct *work);
1830
1831static void dm_init_md_queue(struct mapped_device *md)
1832{
1833	/*
1834	 * Request-based dm devices cannot be stacked on top of bio-based dm
1835	 * devices.  The type of this dm device has not been decided yet.
1836	 * The type is decided at the first table loading time.
1837	 * To prevent problematic device stacking, clear the queue flag
1838	 * for request stacking support until then.
1839	 *
1840	 * This queue is new, so no concurrency on the queue_flags.
1841	 */
1842	queue_flag_clear_unlocked(QUEUE_FLAG_STACKABLE, md->queue);
1843
1844	md->queue->queuedata = md;
1845	md->queue->backing_dev_info.congested_fn = dm_any_congested;
1846	md->queue->backing_dev_info.congested_data = md;
1847	blk_queue_make_request(md->queue, dm_request);
1848	blk_queue_bounce_limit(md->queue, BLK_BOUNCE_ANY);
1849	blk_queue_merge_bvec(md->queue, dm_merge_bvec);
1850}
1851
1852/*
1853 * Allocate and initialise a blank device with a given minor.
1854 */
1855static struct mapped_device *alloc_dev(int minor)
1856{
1857	int r;
1858	struct mapped_device *md = kzalloc(sizeof(*md), GFP_KERNEL);
1859	void *old_md;
1860
1861	if (!md) {
1862		DMWARN("unable to allocate device, out of memory.");
1863		return NULL;
1864	}
1865
1866	if (!try_module_get(THIS_MODULE))
1867		goto bad_module_get;
1868
1869	/* get a minor number for the dev */
1870	if (minor == DM_ANY_MINOR)
1871		r = next_free_minor(&minor);
1872	else
1873		r = specific_minor(minor);
1874	if (r < 0)
1875		goto bad_minor;
1876
1877	r = init_srcu_struct(&md->io_barrier);
1878	if (r < 0)
1879		goto bad_io_barrier;
1880
1881	md->type = DM_TYPE_NONE;
 
1882	mutex_init(&md->suspend_lock);
1883	mutex_init(&md->type_lock);
1884	spin_lock_init(&md->deferred_lock);
 
1885	atomic_set(&md->holders, 1);
1886	atomic_set(&md->open_count, 0);
1887	atomic_set(&md->event_nr, 0);
1888	atomic_set(&md->uevent_seq, 0);
1889	INIT_LIST_HEAD(&md->uevent_list);
1890	spin_lock_init(&md->uevent_lock);
1891
1892	md->queue = blk_alloc_queue(GFP_KERNEL);
1893	if (!md->queue)
1894		goto bad_queue;
1895
1896	dm_init_md_queue(md);
1897
1898	md->disk = alloc_disk(1);
1899	if (!md->disk)
1900		goto bad_disk;
1901
1902	atomic_set(&md->pending[0], 0);
1903	atomic_set(&md->pending[1], 0);
1904	init_waitqueue_head(&md->wait);
1905	INIT_WORK(&md->work, dm_wq_work);
1906	init_waitqueue_head(&md->eventq);
1907	init_completion(&md->kobj_holder.completion);
1908
1909	md->disk->major = _major;
1910	md->disk->first_minor = minor;
1911	md->disk->fops = &dm_blk_dops;
1912	md->disk->queue = md->queue;
1913	md->disk->private_data = md;
1914	sprintf(md->disk->disk_name, "dm-%d", minor);
1915	add_disk(md->disk);
1916	format_dev_t(md->name, MKDEV(_major, minor));
1917
1918	md->wq = alloc_workqueue("kdmflush", WQ_MEM_RECLAIM, 0);
 
1919	if (!md->wq)
1920		goto bad_thread;
1921
1922	md->bdev = bdget_disk(md->disk, 0);
1923	if (!md->bdev)
1924		goto bad_bdev;
1925
1926	bio_init(&md->flush_bio);
1927	md->flush_bio.bi_bdev = md->bdev;
1928	md->flush_bio.bi_rw = WRITE_FLUSH;
1929
1930	dm_stats_init(&md->stats);
1931
1932	/* Populate the mapping, nobody knows we exist yet */
1933	spin_lock(&_minor_lock);
1934	old_md = idr_replace(&_minor_idr, md, minor);
1935	spin_unlock(&_minor_lock);
1936
1937	BUG_ON(old_md != MINOR_ALLOCED);
1938
1939	return md;
1940
1941bad_bdev:
1942	destroy_workqueue(md->wq);
1943bad_thread:
1944	del_gendisk(md->disk);
1945	put_disk(md->disk);
1946bad_disk:
1947	blk_cleanup_queue(md->queue);
1948bad_queue:
1949	cleanup_srcu_struct(&md->io_barrier);
1950bad_io_barrier:
1951	free_minor(minor);
1952bad_minor:
1953	module_put(THIS_MODULE);
1954bad_module_get:
1955	kfree(md);
1956	return NULL;
1957}
1958
1959static void unlock_fs(struct mapped_device *md);
1960
1961static void free_dev(struct mapped_device *md)
1962{
1963	int minor = MINOR(disk_devt(md->disk));
1964
1965	unlock_fs(md);
1966	bdput(md->bdev);
1967	destroy_workqueue(md->wq);
 
 
1968	if (md->io_pool)
1969		mempool_destroy(md->io_pool);
1970	if (md->bs)
1971		bioset_free(md->bs);
1972	blk_integrity_unregister(md->disk);
1973	del_gendisk(md->disk);
1974	cleanup_srcu_struct(&md->io_barrier);
1975	free_minor(minor);
1976
1977	spin_lock(&_minor_lock);
1978	md->disk->private_data = NULL;
1979	spin_unlock(&_minor_lock);
1980
1981	put_disk(md->disk);
1982	blk_cleanup_queue(md->queue);
1983	dm_stats_cleanup(&md->stats);
1984	module_put(THIS_MODULE);
1985	kfree(md);
1986}
1987
1988static void __bind_mempools(struct mapped_device *md, struct dm_table *t)
1989{
1990	struct dm_md_mempools *p = dm_table_get_md_mempools(t);
1991
1992	if (md->io_pool && md->bs) {
1993		/* The md already has necessary mempools. */
1994		if (dm_table_get_type(t) == DM_TYPE_BIO_BASED) {
1995			/*
1996			 * Reload bioset because front_pad may have changed
1997			 * because a different table was loaded.
1998			 */
1999			bioset_free(md->bs);
2000			md->bs = p->bs;
2001			p->bs = NULL;
2002		} else if (dm_table_get_type(t) == DM_TYPE_REQUEST_BASED) {
2003			/*
2004			 * There's no need to reload with request-based dm
2005			 * because the size of front_pad doesn't change.
2006			 * Note for future: If you are to reload bioset,
2007			 * prep-ed requests in the queue may refer
2008			 * to bio from the old bioset, so you must walk
2009			 * through the queue to unprep.
2010			 */
2011		}
2012		goto out;
2013	}
2014
2015	BUG_ON(!p || md->io_pool || md->bs);
 
2016
2017	md->io_pool = p->io_pool;
2018	p->io_pool = NULL;
 
 
2019	md->bs = p->bs;
2020	p->bs = NULL;
2021
2022out:
2023	/* mempool bind completed, now no need any mempools in the table */
2024	dm_table_free_md_mempools(t);
2025}
2026
2027/*
2028 * Bind a table to the device.
2029 */
2030static void event_callback(void *context)
2031{
2032	unsigned long flags;
2033	LIST_HEAD(uevents);
2034	struct mapped_device *md = (struct mapped_device *) context;
2035
2036	spin_lock_irqsave(&md->uevent_lock, flags);
2037	list_splice_init(&md->uevent_list, &uevents);
2038	spin_unlock_irqrestore(&md->uevent_lock, flags);
2039
2040	dm_send_uevents(&uevents, &disk_to_dev(md->disk)->kobj);
2041
2042	atomic_inc(&md->event_nr);
2043	wake_up(&md->eventq);
2044}
2045
2046/*
2047 * Protected by md->suspend_lock obtained by dm_swap_table().
2048 */
2049static void __set_size(struct mapped_device *md, sector_t size)
2050{
2051	set_capacity(md->disk, size);
2052
2053	i_size_write(md->bdev->bd_inode, (loff_t)size << SECTOR_SHIFT);
2054}
2055
2056/*
2057 * Return 1 if the queue has a compulsory merge_bvec_fn function.
2058 *
2059 * If this function returns 0, then the device is either a non-dm
2060 * device without a merge_bvec_fn, or it is a dm device that is
2061 * able to split any bios it receives that are too big.
2062 */
2063int dm_queue_merge_is_compulsory(struct request_queue *q)
2064{
2065	struct mapped_device *dev_md;
2066
2067	if (!q->merge_bvec_fn)
2068		return 0;
2069
2070	if (q->make_request_fn == dm_request) {
2071		dev_md = q->queuedata;
2072		if (test_bit(DMF_MERGE_IS_OPTIONAL, &dev_md->flags))
2073			return 0;
2074	}
2075
2076	return 1;
2077}
2078
2079static int dm_device_merge_is_compulsory(struct dm_target *ti,
2080					 struct dm_dev *dev, sector_t start,
2081					 sector_t len, void *data)
2082{
2083	struct block_device *bdev = dev->bdev;
2084	struct request_queue *q = bdev_get_queue(bdev);
2085
2086	return dm_queue_merge_is_compulsory(q);
2087}
2088
2089/*
2090 * Return 1 if it is acceptable to ignore merge_bvec_fn based
2091 * on the properties of the underlying devices.
2092 */
2093static int dm_table_merge_is_optional(struct dm_table *table)
2094{
2095	unsigned i = 0;
2096	struct dm_target *ti;
2097
2098	while (i < dm_table_get_num_targets(table)) {
2099		ti = dm_table_get_target(table, i++);
2100
2101		if (ti->type->iterate_devices &&
2102		    ti->type->iterate_devices(ti, dm_device_merge_is_compulsory, NULL))
2103			return 0;
2104	}
2105
2106	return 1;
2107}
2108
2109/*
2110 * Returns old map, which caller must destroy.
2111 */
2112static struct dm_table *__bind(struct mapped_device *md, struct dm_table *t,
2113			       struct queue_limits *limits)
2114{
2115	struct dm_table *old_map;
2116	struct request_queue *q = md->queue;
2117	sector_t size;
 
2118	int merge_is_optional;
2119
2120	size = dm_table_get_size(t);
2121
2122	/*
2123	 * Wipe any geometry if the size of the table changed.
2124	 */
2125	if (size != dm_get_size(md))
2126		memset(&md->geometry, 0, sizeof(md->geometry));
2127
2128	__set_size(md, size);
2129
2130	dm_table_event_callback(t, event_callback, md);
2131
2132	/*
2133	 * The queue hasn't been stopped yet, if the old table type wasn't
2134	 * for request-based during suspension.  So stop it to prevent
2135	 * I/O mapping before resume.
2136	 * This must be done before setting the queue restrictions,
2137	 * because request-based dm may be run just after the setting.
2138	 */
2139	if (dm_table_request_based(t) && !blk_queue_stopped(q))
2140		stop_queue(q);
2141
2142	__bind_mempools(md, t);
2143
2144	merge_is_optional = dm_table_merge_is_optional(t);
2145
 
2146	old_map = md->map;
2147	rcu_assign_pointer(md->map, t);
2148	md->immutable_target_type = dm_table_get_immutable_target_type(t);
2149
2150	dm_table_set_restrictions(t, q, limits);
2151	if (merge_is_optional)
2152		set_bit(DMF_MERGE_IS_OPTIONAL, &md->flags);
2153	else
2154		clear_bit(DMF_MERGE_IS_OPTIONAL, &md->flags);
2155	dm_sync_table(md);
2156
2157	return old_map;
2158}
2159
2160/*
2161 * Returns unbound table for the caller to free.
2162 */
2163static struct dm_table *__unbind(struct mapped_device *md)
2164{
2165	struct dm_table *map = md->map;
 
2166
2167	if (!map)
2168		return NULL;
2169
2170	dm_table_event_callback(map, NULL, NULL);
2171	RCU_INIT_POINTER(md->map, NULL);
2172	dm_sync_table(md);
 
2173
2174	return map;
2175}
2176
2177/*
2178 * Constructor for a new device.
2179 */
2180int dm_create(int minor, struct mapped_device **result)
2181{
2182	struct mapped_device *md;
2183
2184	md = alloc_dev(minor);
2185	if (!md)
2186		return -ENXIO;
2187
2188	dm_sysfs_init(md);
2189
2190	*result = md;
2191	return 0;
2192}
2193
2194/*
2195 * Functions to manage md->type.
2196 * All are required to hold md->type_lock.
2197 */
2198void dm_lock_md_type(struct mapped_device *md)
2199{
2200	mutex_lock(&md->type_lock);
2201}
2202
2203void dm_unlock_md_type(struct mapped_device *md)
2204{
2205	mutex_unlock(&md->type_lock);
2206}
2207
2208void dm_set_md_type(struct mapped_device *md, unsigned type)
2209{
2210	BUG_ON(!mutex_is_locked(&md->type_lock));
2211	md->type = type;
2212}
2213
2214unsigned dm_get_md_type(struct mapped_device *md)
2215{
2216	BUG_ON(!mutex_is_locked(&md->type_lock));
2217	return md->type;
2218}
2219
2220struct target_type *dm_get_immutable_target_type(struct mapped_device *md)
2221{
2222	return md->immutable_target_type;
2223}
2224
2225/*
2226 * The queue_limits are only valid as long as you have a reference
2227 * count on 'md'.
2228 */
2229struct queue_limits *dm_get_queue_limits(struct mapped_device *md)
2230{
2231	BUG_ON(!atomic_read(&md->holders));
2232	return &md->queue->limits;
2233}
2234EXPORT_SYMBOL_GPL(dm_get_queue_limits);
2235
2236/*
2237 * Fully initialize a request-based queue (->elevator, ->request_fn, etc).
2238 */
2239static int dm_init_request_based_queue(struct mapped_device *md)
2240{
2241	struct request_queue *q = NULL;
2242
2243	if (md->queue->elevator)
2244		return 1;
2245
2246	/* Fully initialize the queue */
2247	q = blk_init_allocated_queue(md->queue, dm_request_fn, NULL);
2248	if (!q)
2249		return 0;
2250
2251	md->queue = q;
 
2252	dm_init_md_queue(md);
2253	blk_queue_softirq_done(md->queue, dm_softirq_done);
2254	blk_queue_prep_rq(md->queue, dm_prep_fn);
2255	blk_queue_lld_busy(md->queue, dm_lld_busy);
2256
2257	elv_register_queue(md->queue);
2258
2259	return 1;
2260}
2261
2262/*
2263 * Setup the DM device's queue based on md's type
2264 */
2265int dm_setup_md_queue(struct mapped_device *md)
2266{
2267	if ((dm_get_md_type(md) == DM_TYPE_REQUEST_BASED) &&
2268	    !dm_init_request_based_queue(md)) {
2269		DMWARN("Cannot initialize queue for request-based mapped device");
2270		return -EINVAL;
2271	}
2272
2273	return 0;
2274}
2275
2276static struct mapped_device *dm_find_md(dev_t dev)
2277{
2278	struct mapped_device *md;
2279	unsigned minor = MINOR(dev);
2280
2281	if (MAJOR(dev) != _major || minor >= (1 << MINORBITS))
2282		return NULL;
2283
2284	spin_lock(&_minor_lock);
2285
2286	md = idr_find(&_minor_idr, minor);
2287	if (md && (md == MINOR_ALLOCED ||
2288		   (MINOR(disk_devt(dm_disk(md))) != minor) ||
2289		   dm_deleting_md(md) ||
2290		   test_bit(DMF_FREEING, &md->flags))) {
2291		md = NULL;
2292		goto out;
2293	}
2294
2295out:
2296	spin_unlock(&_minor_lock);
2297
2298	return md;
2299}
2300
2301struct mapped_device *dm_get_md(dev_t dev)
2302{
2303	struct mapped_device *md = dm_find_md(dev);
2304
2305	if (md)
2306		dm_get(md);
2307
2308	return md;
2309}
2310EXPORT_SYMBOL_GPL(dm_get_md);
2311
2312void *dm_get_mdptr(struct mapped_device *md)
2313{
2314	return md->interface_ptr;
2315}
2316
2317void dm_set_mdptr(struct mapped_device *md, void *ptr)
2318{
2319	md->interface_ptr = ptr;
2320}
2321
2322void dm_get(struct mapped_device *md)
2323{
2324	atomic_inc(&md->holders);
2325	BUG_ON(test_bit(DMF_FREEING, &md->flags));
2326}
2327
2328const char *dm_device_name(struct mapped_device *md)
2329{
2330	return md->name;
2331}
2332EXPORT_SYMBOL_GPL(dm_device_name);
2333
2334static void __dm_destroy(struct mapped_device *md, bool wait)
2335{
2336	struct dm_table *map;
2337	int srcu_idx;
2338
2339	might_sleep();
2340
2341	spin_lock(&_minor_lock);
2342	map = dm_get_live_table(md, &srcu_idx);
2343	idr_replace(&_minor_idr, MINOR_ALLOCED, MINOR(disk_devt(dm_disk(md))));
2344	set_bit(DMF_FREEING, &md->flags);
2345	spin_unlock(&_minor_lock);
2346
2347	if (!dm_suspended_md(md)) {
2348		dm_table_presuspend_targets(map);
2349		dm_table_postsuspend_targets(map);
2350	}
2351
2352	/* dm_put_live_table must be before msleep, otherwise deadlock is possible */
2353	dm_put_live_table(md, srcu_idx);
2354
2355	/*
2356	 * Rare, but there may be I/O requests still going to complete,
2357	 * for example.  Wait for all references to disappear.
2358	 * No one should increment the reference count of the mapped_device,
2359	 * after the mapped_device state becomes DMF_FREEING.
2360	 */
2361	if (wait)
2362		while (atomic_read(&md->holders))
2363			msleep(1);
2364	else if (atomic_read(&md->holders))
2365		DMWARN("%s: Forcibly removing mapped_device still in use! (%d users)",
2366		       dm_device_name(md), atomic_read(&md->holders));
2367
2368	dm_sysfs_exit(md);
 
2369	dm_table_destroy(__unbind(md));
2370	free_dev(md);
2371}
2372
2373void dm_destroy(struct mapped_device *md)
2374{
2375	__dm_destroy(md, true);
2376}
2377
2378void dm_destroy_immediate(struct mapped_device *md)
2379{
2380	__dm_destroy(md, false);
2381}
2382
2383void dm_put(struct mapped_device *md)
2384{
2385	atomic_dec(&md->holders);
2386}
2387EXPORT_SYMBOL_GPL(dm_put);
2388
2389static int dm_wait_for_completion(struct mapped_device *md, int interruptible)
2390{
2391	int r = 0;
2392	DECLARE_WAITQUEUE(wait, current);
2393
2394	add_wait_queue(&md->wait, &wait);
2395
2396	while (1) {
2397		set_current_state(interruptible);
2398
 
2399		if (!md_in_flight(md))
2400			break;
2401
2402		if (interruptible == TASK_INTERRUPTIBLE &&
2403		    signal_pending(current)) {
2404			r = -EINTR;
2405			break;
2406		}
2407
2408		io_schedule();
2409	}
2410	set_current_state(TASK_RUNNING);
2411
2412	remove_wait_queue(&md->wait, &wait);
2413
2414	return r;
2415}
2416
2417/*
2418 * Process the deferred bios
2419 */
2420static void dm_wq_work(struct work_struct *work)
2421{
2422	struct mapped_device *md = container_of(work, struct mapped_device,
2423						work);
2424	struct bio *c;
2425	int srcu_idx;
2426	struct dm_table *map;
2427
2428	map = dm_get_live_table(md, &srcu_idx);
2429
2430	while (!test_bit(DMF_BLOCK_IO_FOR_SUSPEND, &md->flags)) {
2431		spin_lock_irq(&md->deferred_lock);
2432		c = bio_list_pop(&md->deferred);
2433		spin_unlock_irq(&md->deferred_lock);
2434
2435		if (!c)
2436			break;
2437
 
 
2438		if (dm_request_based(md))
2439			generic_make_request(c);
2440		else
2441			__split_and_process_bio(md, map, c);
 
 
2442	}
2443
2444	dm_put_live_table(md, srcu_idx);
2445}
2446
2447static void dm_queue_flush(struct mapped_device *md)
2448{
2449	clear_bit(DMF_BLOCK_IO_FOR_SUSPEND, &md->flags);
2450	smp_mb__after_clear_bit();
2451	queue_work(md->wq, &md->work);
2452}
2453
2454/*
2455 * Swap in a new table, returning the old one for the caller to destroy.
2456 */
2457struct dm_table *dm_swap_table(struct mapped_device *md, struct dm_table *table)
2458{
2459	struct dm_table *live_map = NULL, *map = ERR_PTR(-EINVAL);
2460	struct queue_limits limits;
2461	int r;
2462
2463	mutex_lock(&md->suspend_lock);
2464
2465	/* device must be suspended */
2466	if (!dm_suspended_md(md))
2467		goto out;
2468
2469	/*
2470	 * If the new table has no data devices, retain the existing limits.
2471	 * This helps multipath with queue_if_no_path if all paths disappear,
2472	 * then new I/O is queued based on these limits, and then some paths
2473	 * reappear.
2474	 */
2475	if (dm_table_has_no_data_devices(table)) {
2476		live_map = dm_get_live_table_fast(md);
2477		if (live_map)
2478			limits = md->queue->limits;
2479		dm_put_live_table_fast(md);
2480	}
2481
2482	if (!live_map) {
2483		r = dm_calculate_queue_limits(table, &limits);
2484		if (r) {
2485			map = ERR_PTR(r);
2486			goto out;
2487		}
2488	}
2489
2490	map = __bind(md, table, &limits);
2491
2492out:
2493	mutex_unlock(&md->suspend_lock);
2494	return map;
2495}
2496
2497/*
2498 * Functions to lock and unlock any filesystem running on the
2499 * device.
2500 */
2501static int lock_fs(struct mapped_device *md)
2502{
2503	int r;
2504
2505	WARN_ON(md->frozen_sb);
2506
2507	md->frozen_sb = freeze_bdev(md->bdev);
2508	if (IS_ERR(md->frozen_sb)) {
2509		r = PTR_ERR(md->frozen_sb);
2510		md->frozen_sb = NULL;
2511		return r;
2512	}
2513
2514	set_bit(DMF_FROZEN, &md->flags);
2515
2516	return 0;
2517}
2518
2519static void unlock_fs(struct mapped_device *md)
2520{
2521	if (!test_bit(DMF_FROZEN, &md->flags))
2522		return;
2523
2524	thaw_bdev(md->bdev, md->frozen_sb);
2525	md->frozen_sb = NULL;
2526	clear_bit(DMF_FROZEN, &md->flags);
2527}
2528
2529/*
2530 * We need to be able to change a mapping table under a mounted
2531 * filesystem.  For example we might want to move some data in
2532 * the background.  Before the table can be swapped with
2533 * dm_bind_table, dm_suspend must be called to flush any in
2534 * flight bios and ensure that any further io gets deferred.
2535 */
2536/*
2537 * Suspend mechanism in request-based dm.
2538 *
2539 * 1. Flush all I/Os by lock_fs() if needed.
2540 * 2. Stop dispatching any I/O by stopping the request_queue.
2541 * 3. Wait for all in-flight I/Os to be completed or requeued.
2542 *
2543 * To abort suspend, start the request_queue.
2544 */
2545int dm_suspend(struct mapped_device *md, unsigned suspend_flags)
2546{
2547	struct dm_table *map = NULL;
2548	int r = 0;
2549	int do_lockfs = suspend_flags & DM_SUSPEND_LOCKFS_FLAG ? 1 : 0;
2550	int noflush = suspend_flags & DM_SUSPEND_NOFLUSH_FLAG ? 1 : 0;
2551
2552	mutex_lock(&md->suspend_lock);
2553
2554	if (dm_suspended_md(md)) {
2555		r = -EINVAL;
2556		goto out_unlock;
2557	}
2558
2559	map = md->map;
2560
2561	/*
2562	 * DMF_NOFLUSH_SUSPENDING must be set before presuspend.
2563	 * This flag is cleared before dm_suspend returns.
2564	 */
2565	if (noflush)
2566		set_bit(DMF_NOFLUSH_SUSPENDING, &md->flags);
2567
2568	/* This does not get reverted if there's an error later. */
2569	dm_table_presuspend_targets(map);
2570
2571	/*
2572	 * Flush I/O to the device.
2573	 * Any I/O submitted after lock_fs() may not be flushed.
2574	 * noflush takes precedence over do_lockfs.
2575	 * (lock_fs() flushes I/Os and waits for them to complete.)
2576	 */
2577	if (!noflush && do_lockfs) {
2578		r = lock_fs(md);
2579		if (r)
2580			goto out_unlock;
2581	}
2582
2583	/*
2584	 * Here we must make sure that no processes are submitting requests
2585	 * to target drivers i.e. no one may be executing
2586	 * __split_and_process_bio. This is called from dm_request and
2587	 * dm_wq_work.
2588	 *
2589	 * To get all processes out of __split_and_process_bio in dm_request,
2590	 * we take the write lock. To prevent any process from reentering
2591	 * __split_and_process_bio from dm_request and quiesce the thread
2592	 * (dm_wq_work), we set BMF_BLOCK_IO_FOR_SUSPEND and call
2593	 * flush_workqueue(md->wq).
2594	 */
 
2595	set_bit(DMF_BLOCK_IO_FOR_SUSPEND, &md->flags);
2596	synchronize_srcu(&md->io_barrier);
2597
2598	/*
2599	 * Stop md->queue before flushing md->wq in case request-based
2600	 * dm defers requests to md->wq from md->queue.
2601	 */
2602	if (dm_request_based(md))
2603		stop_queue(md->queue);
2604
2605	flush_workqueue(md->wq);
2606
2607	/*
2608	 * At this point no more requests are entering target request routines.
2609	 * We call dm_wait_for_completion to wait for all existing requests
2610	 * to finish.
2611	 */
2612	r = dm_wait_for_completion(md, TASK_INTERRUPTIBLE);
2613
 
2614	if (noflush)
2615		clear_bit(DMF_NOFLUSH_SUSPENDING, &md->flags);
2616	synchronize_srcu(&md->io_barrier);
2617
2618	/* were we interrupted ? */
2619	if (r < 0) {
2620		dm_queue_flush(md);
2621
2622		if (dm_request_based(md))
2623			start_queue(md->queue);
2624
2625		unlock_fs(md);
2626		goto out_unlock; /* pushback list is already flushed, so skip flush */
2627	}
2628
2629	/*
2630	 * If dm_wait_for_completion returned 0, the device is completely
2631	 * quiescent now. There is no request-processing activity. All new
2632	 * requests are being added to md->deferred list.
2633	 */
2634
2635	set_bit(DMF_SUSPENDED, &md->flags);
2636
2637	dm_table_postsuspend_targets(map);
2638
 
 
 
2639out_unlock:
2640	mutex_unlock(&md->suspend_lock);
2641	return r;
2642}
2643
2644int dm_resume(struct mapped_device *md)
2645{
2646	int r = -EINVAL;
2647	struct dm_table *map = NULL;
2648
2649	mutex_lock(&md->suspend_lock);
2650	if (!dm_suspended_md(md))
2651		goto out;
2652
2653	map = md->map;
2654	if (!map || !dm_table_get_size(map))
2655		goto out;
2656
2657	r = dm_table_resume_targets(map);
2658	if (r)
2659		goto out;
2660
2661	dm_queue_flush(md);
2662
2663	/*
2664	 * Flushing deferred I/Os must be done after targets are resumed
2665	 * so that mapping of targets can work correctly.
2666	 * Request-based dm is queueing the deferred I/Os in its request_queue.
2667	 */
2668	if (dm_request_based(md))
2669		start_queue(md->queue);
2670
2671	unlock_fs(md);
2672
2673	clear_bit(DMF_SUSPENDED, &md->flags);
2674
2675	r = 0;
2676out:
 
2677	mutex_unlock(&md->suspend_lock);
2678
2679	return r;
2680}
2681
2682/*
2683 * Internal suspend/resume works like userspace-driven suspend. It waits
2684 * until all bios finish and prevents issuing new bios to the target drivers.
2685 * It may be used only from the kernel.
2686 *
2687 * Internal suspend holds md->suspend_lock, which prevents interaction with
2688 * userspace-driven suspend.
2689 */
2690
2691void dm_internal_suspend(struct mapped_device *md)
2692{
2693	mutex_lock(&md->suspend_lock);
2694	if (dm_suspended_md(md))
2695		return;
2696
2697	set_bit(DMF_BLOCK_IO_FOR_SUSPEND, &md->flags);
2698	synchronize_srcu(&md->io_barrier);
2699	flush_workqueue(md->wq);
2700	dm_wait_for_completion(md, TASK_UNINTERRUPTIBLE);
2701}
2702
2703void dm_internal_resume(struct mapped_device *md)
2704{
2705	if (dm_suspended_md(md))
2706		goto done;
2707
2708	dm_queue_flush(md);
2709
2710done:
2711	mutex_unlock(&md->suspend_lock);
2712}
2713
2714/*-----------------------------------------------------------------
2715 * Event notification.
2716 *---------------------------------------------------------------*/
2717int dm_kobject_uevent(struct mapped_device *md, enum kobject_action action,
2718		       unsigned cookie)
2719{
2720	char udev_cookie[DM_COOKIE_LENGTH];
2721	char *envp[] = { udev_cookie, NULL };
2722
2723	if (!cookie)
2724		return kobject_uevent(&disk_to_dev(md->disk)->kobj, action);
2725	else {
2726		snprintf(udev_cookie, DM_COOKIE_LENGTH, "%s=%u",
2727			 DM_COOKIE_ENV_VAR_NAME, cookie);
2728		return kobject_uevent_env(&disk_to_dev(md->disk)->kobj,
2729					  action, envp);
2730	}
2731}
2732
2733uint32_t dm_next_uevent_seq(struct mapped_device *md)
2734{
2735	return atomic_add_return(1, &md->uevent_seq);
2736}
2737
2738uint32_t dm_get_event_nr(struct mapped_device *md)
2739{
2740	return atomic_read(&md->event_nr);
2741}
2742
2743int dm_wait_event(struct mapped_device *md, int event_nr)
2744{
2745	return wait_event_interruptible(md->eventq,
2746			(event_nr != atomic_read(&md->event_nr)));
2747}
2748
2749void dm_uevent_add(struct mapped_device *md, struct list_head *elist)
2750{
2751	unsigned long flags;
2752
2753	spin_lock_irqsave(&md->uevent_lock, flags);
2754	list_add(elist, &md->uevent_list);
2755	spin_unlock_irqrestore(&md->uevent_lock, flags);
2756}
2757
2758/*
2759 * The gendisk is only valid as long as you have a reference
2760 * count on 'md'.
2761 */
2762struct gendisk *dm_disk(struct mapped_device *md)
2763{
2764	return md->disk;
2765}
2766
2767struct kobject *dm_kobject(struct mapped_device *md)
2768{
2769	return &md->kobj_holder.kobj;
2770}
2771
 
 
 
 
2772struct mapped_device *dm_get_from_kobject(struct kobject *kobj)
2773{
2774	struct mapped_device *md;
2775
2776	md = container_of(kobj, struct mapped_device, kobj_holder.kobj);
 
 
2777
2778	if (test_bit(DMF_FREEING, &md->flags) ||
2779	    dm_deleting_md(md))
2780		return NULL;
2781
2782	dm_get(md);
2783	return md;
2784}
2785
2786int dm_suspended_md(struct mapped_device *md)
2787{
2788	return test_bit(DMF_SUSPENDED, &md->flags);
2789}
2790
2791int dm_test_deferred_remove_flag(struct mapped_device *md)
2792{
2793	return test_bit(DMF_DEFERRED_REMOVE, &md->flags);
2794}
2795
2796int dm_suspended(struct dm_target *ti)
2797{
2798	return dm_suspended_md(dm_table_get_md(ti->table));
2799}
2800EXPORT_SYMBOL_GPL(dm_suspended);
2801
2802int dm_noflush_suspending(struct dm_target *ti)
2803{
2804	return __noflush_suspending(dm_table_get_md(ti->table));
2805}
2806EXPORT_SYMBOL_GPL(dm_noflush_suspending);
2807
2808struct dm_md_mempools *dm_alloc_md_mempools(unsigned type, unsigned integrity, unsigned per_bio_data_size)
2809{
2810	struct dm_md_mempools *pools = kzalloc(sizeof(*pools), GFP_KERNEL);
2811	struct kmem_cache *cachep;
2812	unsigned int pool_size;
2813	unsigned int front_pad;
2814
2815	if (!pools)
2816		return NULL;
2817
2818	if (type == DM_TYPE_BIO_BASED) {
2819		cachep = _io_cache;
2820		pool_size = dm_get_reserved_bio_based_ios();
2821		front_pad = roundup(per_bio_data_size, __alignof__(struct dm_target_io)) + offsetof(struct dm_target_io, clone);
2822	} else if (type == DM_TYPE_REQUEST_BASED) {
2823		cachep = _rq_tio_cache;
2824		pool_size = dm_get_reserved_rq_based_ios();
2825		front_pad = offsetof(struct dm_rq_clone_bio_info, clone);
2826		/* per_bio_data_size is not used. See __bind_mempools(). */
2827		WARN_ON(per_bio_data_size != 0);
2828	} else
2829		goto out;
2830
2831	pools->io_pool = mempool_create_slab_pool(pool_size, cachep);
2832	if (!pools->io_pool)
2833		goto out;
2834
2835	pools->bs = bioset_create(pool_size, front_pad);
 
 
 
 
 
 
2836	if (!pools->bs)
2837		goto out;
2838
2839	if (integrity && bioset_integrity_create(pools->bs, pool_size))
2840		goto out;
2841
2842	return pools;
2843
2844out:
2845	dm_free_md_mempools(pools);
 
 
 
 
 
 
 
 
 
2846
2847	return NULL;
2848}
2849
2850void dm_free_md_mempools(struct dm_md_mempools *pools)
2851{
2852	if (!pools)
2853		return;
2854
2855	if (pools->io_pool)
2856		mempool_destroy(pools->io_pool);
2857
 
 
 
2858	if (pools->bs)
2859		bioset_free(pools->bs);
2860
2861	kfree(pools);
2862}
2863
2864static const struct block_device_operations dm_blk_dops = {
2865	.open = dm_blk_open,
2866	.release = dm_blk_close,
2867	.ioctl = dm_blk_ioctl,
2868	.getgeo = dm_blk_getgeo,
2869	.owner = THIS_MODULE
2870};
2871
 
 
2872/*
2873 * module hooks
2874 */
2875module_init(dm_init);
2876module_exit(dm_exit);
2877
2878module_param(major, uint, 0);
2879MODULE_PARM_DESC(major, "The major number of the device mapper");
2880
2881module_param(reserved_bio_based_ios, uint, S_IRUGO | S_IWUSR);
2882MODULE_PARM_DESC(reserved_bio_based_ios, "Reserved IOs in bio-based mempools");
2883
2884module_param(reserved_rq_based_ios, uint, S_IRUGO | S_IWUSR);
2885MODULE_PARM_DESC(reserved_rq_based_ios, "Reserved IOs in request-based mempools");
2886
2887MODULE_DESCRIPTION(DM_NAME " driver");
2888MODULE_AUTHOR("Joe Thornber <dm-devel@redhat.com>");
2889MODULE_LICENSE("GPL");