drivers/md/dm-rq.c

   1 /*
   2  * Copyright (C) 2016 Red Hat, Inc. All rights reserved.
   3  *
   4  * This file is released under the GPL.
   5  */
   6
   7 #include "dm-core.h"
   8 #include "dm-rq.h"
   9
  10 #include <linux/elevator.h> /* for rq_end_sector() */
  11 #include <linux/blk-mq.h>
  12
  13 #define DM_MSG_PREFIX "core-rq"
  14
  15 #define DM_MQ_NR_HW_QUEUES 1
  16 #define DM_MQ_QUEUE_DEPTH 2048
  17 static unsigned dm_mq_nr_hw_queues = DM_MQ_NR_HW_QUEUES;
  18 static unsigned dm_mq_queue_depth = DM_MQ_QUEUE_DEPTH;
  19
  20 /*
  21  * Request-based DM's mempools' reserved IOs set by the user.
  22  */
  23 #define RESERVED_REQUEST_BASED_IOS      256
  24 static unsigned reserved_rq_based_ios = RESERVED_REQUEST_BASED_IOS;
  25
  26 static bool use_blk_mq = IS_ENABLED(CONFIG_DM_MQ_DEFAULT);
  27
  28 bool dm_use_blk_mq_default(void)
  29 {
  30         return use_blk_mq;
  31 }
  32
  33 bool dm_use_blk_mq(struct mapped_device *md)
  34 {
  35         return md->use_blk_mq;
  36 }
  37 EXPORT_SYMBOL_GPL(dm_use_blk_mq);
  38
  39 unsigned dm_get_reserved_rq_based_ios(void)
  40 {
  41         return __dm_get_module_param(&reserved_rq_based_ios,
  42                                      RESERVED_REQUEST_BASED_IOS, DM_RESERVED_MAX_IOS);
  43 }
  44 EXPORT_SYMBOL_GPL(dm_get_reserved_rq_based_ios);
  45
  46 static unsigned dm_get_blk_mq_nr_hw_queues(void)
  47 {
  48         return __dm_get_module_param(&dm_mq_nr_hw_queues, 1, 32);
  49 }
  50
  51 static unsigned dm_get_blk_mq_queue_depth(void)
  52 {
  53         return __dm_get_module_param(&dm_mq_queue_depth,
  54                                      DM_MQ_QUEUE_DEPTH, BLK_MQ_MAX_DEPTH);
  55 }
  56
  57 int dm_request_based(struct mapped_device *md)
  58 {
  59         return queue_is_rq_based(md->queue);
  60 }
  61
  62 static void dm_old_start_queue(struct request_queue *q)
  63 {
  64         unsigned long flags;
  65
  66         spin_lock_irqsave(q->queue_lock, flags);
  67         if (blk_queue_stopped(q))
  68                 blk_start_queue(q);
  69         spin_unlock_irqrestore(q->queue_lock, flags);
  70 }
  71
  72 static void dm_mq_start_queue(struct request_queue *q)
  73 {
  74         blk_mq_unquiesce_queue(q);
  75         blk_mq_kick_requeue_list(q);
  76 }
  77
  78 void dm_start_queue(struct request_queue *q)
  79 {
  80         if (!q->mq_ops)
  81                 dm_old_start_queue(q);
  82         else
  83                 dm_mq_start_queue(q);
  84 }
  85
  86 static void dm_old_stop_queue(struct request_queue *q)
  87 {
  88         unsigned long flags;
  89
  90         spin_lock_irqsave(q->queue_lock, flags);
  91         if (!blk_queue_stopped(q))
  92                 blk_stop_queue(q);
  93         spin_unlock_irqrestore(q->queue_lock, flags);
  94 }
  95
  96 static void dm_mq_stop_queue(struct request_queue *q)
  97 {
  98         if (blk_mq_queue_stopped(q))
  99                 return;
 100
 101         blk_mq_quiesce_queue(q);
 102 }
 103
 104 void dm_stop_queue(struct request_queue *q)
 105 {
 106         if (!q->mq_ops)
 107                 dm_old_stop_queue(q);
 108         else
 109                 dm_mq_stop_queue(q);
 110 }
 111
 112 /*
 113  * Partial completion handling for request-based dm
 114  */
 115 static void end_clone_bio(struct bio *clone)
 116 {
 117         struct dm_rq_clone_bio_info *info =
 118                 container_of(clone, struct dm_rq_clone_bio_info, clone);
 119         struct dm_rq_target_io *tio = info->tio;
 120         unsigned int nr_bytes = info->orig->bi_iter.bi_size;
 121         blk_status_t error = clone->bi_status;
 122         bool is_last = !clone->bi_next;
 123
 124         bio_put(clone);
 125
 126         if (tio->error)
 127                 /*
 128                  * An error has already been detected on the request.
 129                  * Once error occurred, just let clone->end_io() handle
 130                  * the remainder.
 131                  */
 132                 return;
 133         else if (error) {
 134                 /*
 135                  * Don't notice the error to the upper layer yet.
 136                  * The error handling decision is made by the target driver,
 137                  * when the request is completed.
 138                  */
 139                 tio->error = error;
 140                 goto exit;
 141         }
 142
 143         /*
 144          * I/O for the bio successfully completed.
 145          * Notice the data completion to the upper layer.
 146          */
 147         tio->completed += nr_bytes;
 148
 149         /*
 150          * Update the original request.
 151          * Do not use blk_end_request() here, because it may complete
 152          * the original request before the clone, and break the ordering.
 153          */
 154         if (is_last)
 155  exit:
 156                 blk_update_request(tio->orig, BLK_STS_OK, tio->completed);
 157 }
 158
 159 static struct dm_rq_target_io *tio_from_request(struct request *rq)
 160 {
 161         return blk_mq_rq_to_pdu(rq);
 162 }
 163
 164 static void rq_end_stats(struct mapped_device *md, struct request *orig)
 165 {
 166         if (unlikely(dm_stats_used(&md->stats))) {
 167                 struct dm_rq_target_io *tio = tio_from_request(orig);
 168                 tio->duration_jiffies = jiffies - tio->duration_jiffies;
 169                 dm_stats_account_io(&md->stats, rq_data_dir(orig),
 170                                     blk_rq_pos(orig), tio->n_sectors, true,
 171                                     tio->duration_jiffies, &tio->stats_aux);
 172         }
 173 }
 174
 175 /*
 176  * Don't touch any member of the md after calling this function because
 177  * the md may be freed in dm_put() at the end of this function.
 178  * Or do dm_get() before calling this function and dm_put() later.
 179  */
 180 static void rq_completed(struct mapped_device *md, int rw, bool run_queue)
 181 {
 182         struct request_queue *q = md->queue;
 183         unsigned long flags;
 184
 185         atomic_dec(&md->pending[rw]);
 186
 187         /* nudge anyone waiting on suspend queue */
 188         if (!md_in_flight(md))
 189                 wake_up(&md->wait);
 190
 191         /*
 192          * Run this off this callpath, as drivers could invoke end_io while
 193          * inside their request_fn (and holding the queue lock). Calling
 194          * back into ->request_fn() could deadlock attempting to grab the
 195          * queue lock again.
 196          */
 197         if (!q->mq_ops && run_queue) {
 198                 spin_lock_irqsave(q->queue_lock, flags);
 199                 blk_run_queue_async(q);
 200                 spin_unlock_irqrestore(q->queue_lock, flags);
 201         }
 202
 203         /*
 204          * dm_put() must be at the end of this function. See the comment above
 205          */
 206         dm_put(md);
 207 }
 208
 209 /*
 210  * Complete the clone and the original request.
 211  * Must be called without clone's queue lock held,
 212  * see end_clone_request() for more details.
 213  */
 214 static void dm_end_request(struct request *clone, blk_status_t error)
 215 {
 216         int rw = rq_data_dir(clone);
 217         struct dm_rq_target_io *tio = clone->end_io_data;
 218         struct mapped_device *md = tio->md;
 219         struct request *rq = tio->orig;
 220
 221         blk_rq_unprep_clone(clone);
 222         tio->ti->type->release_clone_rq(clone);
 223
 224         rq_end_stats(md, rq);
 225         if (!rq->q->mq_ops)
 226                 blk_end_request_all(rq, error);
 227         else
 228                 blk_mq_end_request(rq, error);
 229         rq_completed(md, rw, true);
 230 }
 231
 232 /*
 233  * Requeue the original request of a clone.
 234  */
 235 static void dm_old_requeue_request(struct request *rq, unsigned long delay_ms)
 236 {
 237         struct request_queue *q = rq->q;
 238         unsigned long flags;
 239
 240         spin_lock_irqsave(q->queue_lock, flags);
 241         blk_requeue_request(q, rq);
 242         blk_delay_queue(q, delay_ms);
 243         spin_unlock_irqrestore(q->queue_lock, flags);
 244 }
 245
 246 static void __dm_mq_kick_requeue_list(struct request_queue *q, unsigned long msecs)
 247 {
 248         blk_mq_delay_kick_requeue_list(q, msecs);
 249 }
 250
 251 void dm_mq_kick_requeue_list(struct mapped_device *md)
 252 {
 253         __dm_mq_kick_requeue_list(dm_get_md_queue(md), 0);
 254 }
 255 EXPORT_SYMBOL(dm_mq_kick_requeue_list);
 256
 257 static void dm_mq_delay_requeue_request(struct request *rq, unsigned long msecs)
 258 {
 259         blk_mq_requeue_request(rq, false);
 260         __dm_mq_kick_requeue_list(rq->q, msecs);
 261 }
 262
 263 static void dm_requeue_original_request(struct dm_rq_target_io *tio, bool delay_requeue)
 264 {
 265         struct mapped_device *md = tio->md;
 266         struct request *rq = tio->orig;
 267         int rw = rq_data_dir(rq);
 268         unsigned long delay_ms = delay_requeue ? 100 : 0;
 269
 270         rq_end_stats(md, rq);
 271         if (tio->clone) {
 272                 blk_rq_unprep_clone(tio->clone);
 273                 tio->ti->type->release_clone_rq(tio->clone);
 274         }
 275
 276         if (!rq->q->mq_ops)
 277                 dm_old_requeue_request(rq, delay_ms);
 278         else
 279                 dm_mq_delay_requeue_request(rq, delay_ms);
 280
 281         rq_completed(md, rw, false);
 282 }
 283
 284 static void dm_done(struct request *clone, blk_status_t error, bool mapped)
 285 {
 286         int r = DM_ENDIO_DONE;
 287         struct dm_rq_target_io *tio = clone->end_io_data;
 288         dm_request_endio_fn rq_end_io = NULL;
 289
 290         if (tio->ti) {
 291                 rq_end_io = tio->ti->type->rq_end_io;
 292
 293                 if (mapped && rq_end_io)
 294                         r = rq_end_io(tio->ti, clone, error, &tio->info);
 295         }
 296
 297         if (unlikely(error == BLK_STS_TARGET)) {
 298                 if (req_op(clone) == REQ_OP_WRITE_SAME &&
 299                     !clone->q->limits.max_write_same_sectors)
 300                         disable_write_same(tio->md);
 301                 if (req_op(clone) == REQ_OP_WRITE_ZEROES &&
 302                     !clone->q->limits.max_write_zeroes_sectors)
 303                         disable_write_zeroes(tio->md);
 304         }
 305
 306         switch (r) {
 307         case DM_ENDIO_DONE:
 308                 /* The target wants to complete the I/O */
 309                 dm_end_request(clone, error);
 310                 break;
 311         case DM_ENDIO_INCOMPLETE:
 312                 /* The target will handle the I/O */
 313                 return;
 314         case DM_ENDIO_REQUEUE:
 315                 /* The target wants to requeue the I/O */
 316                 dm_requeue_original_request(tio, false);
 317                 break;
 318         default:
 319                 DMWARN("unimplemented target endio return value: %d", r);
 320                 BUG();
 321         }
 322 }
 323
 324 /*
 325  * Request completion handler for request-based dm
 326  */
 327 static void dm_softirq_done(struct request *rq)
 328 {
 329         bool mapped = true;
 330         struct dm_rq_target_io *tio = tio_from_request(rq);
 331         struct request *clone = tio->clone;
 332         int rw;
 333
 334         if (!clone) {
 335                 struct mapped_device *md = tio->md;
 336
 337                 rq_end_stats(md, rq);
 338                 rw = rq_data_dir(rq);
 339                 if (!rq->q->mq_ops)
 340                         blk_end_request_all(rq, tio->error);
 341                 else
 342                         blk_mq_end_request(rq, tio->error);
 343                 rq_completed(md, rw, false);
 344                 return;
 345         }
 346
 347         if (rq->rq_flags & RQF_FAILED)
 348                 mapped = false;
 349
 350         dm_done(clone, tio->error, mapped);
 351 }
 352
 353 /*
 354  * Complete the clone and the original request with the error status
 355  * through softirq context.
 356  */
 357 static void dm_complete_request(struct request *rq, blk_status_t error)
 358 {
 359         struct dm_rq_target_io *tio = tio_from_request(rq);
 360
 361         tio->error = error;
 362         if (!rq->q->mq_ops)
 363                 blk_complete_request(rq);
 364         else
 365                 blk_mq_complete_request(rq);
 366 }
 367
 368 /*
 369  * Complete the not-mapped clone and the original request with the error status
 370  * through softirq context.
 371  * Target's rq_end_io() function isn't called.
 372  * This may be used when the target's map_rq() or clone_and_map_rq() functions fail.
 373  */
 374 static void dm_kill_unmapped_request(struct request *rq, blk_status_t error)
 375 {
 376         rq->rq_flags |= RQF_FAILED;
 377         dm_complete_request(rq, error);
 378 }
 379
 380 /*
 381  * Called with the clone's queue lock held (in the case of .request_fn)
 382  */
 383 static void end_clone_request(struct request *clone, blk_status_t error)
 384 {
 385         struct dm_rq_target_io *tio = clone->end_io_data;
 386
 387         /*
 388          * Actual request completion is done in a softirq context which doesn't
 389          * hold the clone's queue lock.  Otherwise, deadlock could occur because:
 390          *     - another request may be submitted by the upper level driver
 391          *       of the stacking during the completion
 392          *     - the submission which requires queue lock may be done
 393          *       against this clone's queue
 394          */
 395         dm_complete_request(tio->orig, error);
 396 }
 397
 398 static blk_status_t dm_dispatch_clone_request(struct request *clone, struct request *rq)
 399 {
 400         blk_status_t r;
 401
 402         if (blk_queue_io_stat(clone->q))
 403                 clone->rq_flags |= RQF_IO_STAT;
 404
 405         clone->start_time = jiffies;
 406         r = blk_insert_cloned_request(clone->q, clone);
 407         if (r != BLK_STS_OK && r != BLK_STS_RESOURCE)
 408                 /* must complete clone in terms of original request */
 409                 dm_complete_request(rq, r);
 410         return r;
 411 }
 412
 413 static int dm_rq_bio_constructor(struct bio *bio, struct bio *bio_orig,
 414                                  void *data)
 415 {
 416         struct dm_rq_target_io *tio = data;
 417         struct dm_rq_clone_bio_info *info =
 418                 container_of(bio, struct dm_rq_clone_bio_info, clone);
 419
 420         info->orig = bio_orig;
 421         info->tio = tio;
 422         bio->bi_end_io = end_clone_bio;
 423
 424         return 0;
 425 }
 426
 427 static int setup_clone(struct request *clone, struct request *rq,
 428                        struct dm_rq_target_io *tio, gfp_t gfp_mask)
 429 {
 430         int r;
 431
 432         r = blk_rq_prep_clone(clone, rq, tio->md->bs, gfp_mask,
 433                               dm_rq_bio_constructor, tio);
 434         if (r)
 435                 return r;
 436
 437         clone->end_io = end_clone_request;
 438         clone->end_io_data = tio;
 439
 440         tio->clone = clone;
 441
 442         return 0;
 443 }
 444
 445 static void map_tio_request(struct kthread_work *work);
 446
 447 static void init_tio(struct dm_rq_target_io *tio, struct request *rq,
 448                      struct mapped_device *md)
 449 {
 450         tio->md = md;
 451         tio->ti = NULL;
 452         tio->clone = NULL;
 453         tio->orig = rq;
 454         tio->error = 0;
 455         tio->completed = 0;
 456         /*
 457          * Avoid initializing info for blk-mq; it passes
 458          * target-specific data through info.ptr
 459          * (see: dm_mq_init_request)
 460          */
 461         if (!md->init_tio_pdu)
 462                 memset(&tio->info, 0, sizeof(tio->info));
 463         if (md->kworker_task)
 464                 kthread_init_work(&tio->work, map_tio_request);
 465 }
 466
 467 /*
 468  * Returns:
 469  * DM_MAPIO_*       : the request has been processed as indicated
 470  * DM_MAPIO_REQUEUE : the original request needs to be immediately requeued
 471  * < 0              : the request was completed due to failure
 472  */
 473 static int map_request(struct dm_rq_target_io *tio)
 474 {
 475         int r;
 476         struct dm_target *ti = tio->ti;
 477         struct mapped_device *md = tio->md;
 478         struct request *rq = tio->orig;
 479         struct request *clone = NULL;
 480         blk_status_t ret;
 481
 482         r = ti->type->clone_and_map_rq(ti, rq, &tio->info, &clone);
 483 check_again:
 484         switch (r) {
 485         case DM_MAPIO_SUBMITTED:
 486                 /* The target has taken the I/O to submit by itself later */
 487                 break;
 488         case DM_MAPIO_REMAPPED:
 489                 if (setup_clone(clone, rq, tio, GFP_ATOMIC)) {
 490                         /* -ENOMEM */
 491                         ti->type->release_clone_rq(clone);
 492                         return DM_MAPIO_REQUEUE;
 493                 }
 494
 495                 /* The target has remapped the I/O so dispatch it */
 496                 trace_block_rq_remap(clone->q, clone, disk_devt(dm_disk(md)),
 497                                      blk_rq_pos(rq));
 498                 ret = dm_dispatch_clone_request(clone, rq);
 499                 if (ret == BLK_STS_RESOURCE) {
 500                         blk_rq_unprep_clone(clone);
 501                         tio->ti->type->release_clone_rq(clone);
 502                         tio->clone = NULL;
 503                         if (!rq->q->mq_ops)
 504                                 r = DM_MAPIO_DELAY_REQUEUE;
 505                         else
 506                                 r = DM_MAPIO_REQUEUE;
 507                         goto check_again;
 508                 }
 509                 break;
 510         case DM_MAPIO_REQUEUE:
 511                 /* The target wants to requeue the I/O */
 512                 break;
 513         case DM_MAPIO_DELAY_REQUEUE:
 514                 /* The target wants to requeue the I/O after a delay */
 515                 dm_requeue_original_request(tio, true);
 516                 break;
 517         case DM_MAPIO_KILL:
 518                 /* The target wants to complete the I/O */
 519                 dm_kill_unmapped_request(rq, BLK_STS_IOERR);
 520                 break;
 521         default:
 522                 DMWARN("unimplemented target map return value: %d", r);
 523                 BUG();
 524         }
 525
 526         return r;
 527 }
 528
 529 static void dm_start_request(struct mapped_device *md, struct request *orig)
 530 {
 531         if (!orig->q->mq_ops)
 532                 blk_start_request(orig);
 533         else
 534                 blk_mq_start_request(orig);
 535         atomic_inc(&md->pending[rq_data_dir(orig)]);
 536
 537         if (md->seq_rq_merge_deadline_usecs) {
 538                 md->last_rq_pos = rq_end_sector(orig);
 539                 md->last_rq_rw = rq_data_dir(orig);
 540                 md->last_rq_start_time = ktime_get();
 541         }
 542
 543         if (unlikely(dm_stats_used(&md->stats))) {
 544                 struct dm_rq_target_io *tio = tio_from_request(orig);
 545                 tio->duration_jiffies = jiffies;
 546                 tio->n_sectors = blk_rq_sectors(orig);
 547                 dm_stats_account_io(&md->stats, rq_data_dir(orig),
 548                                     blk_rq_pos(orig), tio->n_sectors, false, 0,
 549                                     &tio->stats_aux);
 550         }
 551
 552         /*
 553          * Hold the md reference here for the in-flight I/O.
 554          * We can't rely on the reference count by device opener,
 555          * because the device may be closed during the request completion
 556          * when all bios are completed.
 557          * See the comment in rq_completed() too.
 558          */
 559         dm_get(md);
 560 }
 561
 562 static int __dm_rq_init_rq(struct mapped_device *md, struct request *rq)
 563 {
 564         struct dm_rq_target_io *tio = blk_mq_rq_to_pdu(rq);
 565
 566         /*
 567          * Must initialize md member of tio, otherwise it won't
 568          * be available in dm_mq_queue_rq.
 569          */
 570         tio->md = md;
 571
 572         if (md->init_tio_pdu) {
 573                 /* target-specific per-io data is immediately after the tio */
 574                 tio->info.ptr = tio + 1;
 575         }
 576
 577         return 0;
 578 }
 579
 580 static int dm_rq_init_rq(struct request_queue *q, struct request *rq, gfp_t gfp)
 581 {
 582         return __dm_rq_init_rq(q->rq_alloc_data, rq);
 583 }
 584
 585 static void map_tio_request(struct kthread_work *work)
 586 {
 587         struct dm_rq_target_io *tio = container_of(work, struct dm_rq_target_io, work);
 588
 589         if (map_request(tio) == DM_MAPIO_REQUEUE)
 590                 dm_requeue_original_request(tio, false);
 591 }
 592
 593 ssize_t dm_attr_rq_based_seq_io_merge_deadline_show(struct mapped_device *md, char *buf)
 594 {
 595         return sprintf(buf, "%u\n", md->seq_rq_merge_deadline_usecs);
 596 }
 597
 598 #define MAX_SEQ_RQ_MERGE_DEADLINE_USECS 100000
 599
 600 ssize_t dm_attr_rq_based_seq_io_merge_deadline_store(struct mapped_device *md,
 601                                                      const char *buf, size_t count)
 602 {
 603         unsigned deadline;
 604
 605         if (dm_get_md_type(md) != DM_TYPE_REQUEST_BASED)
 606                 return count;
 607
 608         if (kstrtouint(buf, 10, &deadline))
 609                 return -EINVAL;
 610
 611         if (deadline > MAX_SEQ_RQ_MERGE_DEADLINE_USECS)
 612                 deadline = MAX_SEQ_RQ_MERGE_DEADLINE_USECS;
 613
 614         md->seq_rq_merge_deadline_usecs = deadline;
 615
 616         return count;
 617 }
 618
 619 static bool dm_old_request_peeked_before_merge_deadline(struct mapped_device *md)
 620 {
 621         ktime_t kt_deadline;
 622
 623         if (!md->seq_rq_merge_deadline_usecs)
 624                 return false;
 625
 626         kt_deadline = ns_to_ktime((u64)md->seq_rq_merge_deadline_usecs * NSEC_PER_USEC);
 627         kt_deadline = ktime_add_safe(md->last_rq_start_time, kt_deadline);
 628
 629         return !ktime_after(ktime_get(), kt_deadline);
 630 }
 631
 632 /*
 633  * q->request_fn for old request-based dm.
 634  * Called with the queue lock held.
 635  */
 636 static void dm_old_request_fn(struct request_queue *q)
 637 {
 638         struct mapped_device *md = q->queuedata;
 639         struct dm_target *ti = md->immutable_target;
 640         struct request *rq;
 641         struct dm_rq_target_io *tio;
 642         sector_t pos = 0;
 643
 644         if (unlikely(!ti)) {
 645                 int srcu_idx;
 646                 struct dm_table *map = dm_get_live_table(md, &srcu_idx);
 647
 648                 if (unlikely(!map)) {
 649                         dm_put_live_table(md, srcu_idx);
 650                         return;
 651                 }
 652                 ti = dm_table_find_target(map, pos);
 653                 dm_put_live_table(md, srcu_idx);
 654         }
 655
 656         /*
 657          * For suspend, check blk_queue_stopped() and increment
 658          * ->pending within a single queue_lock not to increment the
 659          * number of in-flight I/Os after the queue is stopped in
 660          * dm_suspend().
 661          */
 662         while (!blk_queue_stopped(q)) {
 663                 rq = blk_peek_request(q);
 664                 if (!rq)
 665                         return;
 666
 667                 /* always use block 0 to find the target for flushes for now */
 668                 pos = 0;
 669                 if (req_op(rq) != REQ_OP_FLUSH)
 670                         pos = blk_rq_pos(rq);
 671
 672                 if ((dm_old_request_peeked_before_merge_deadline(md) &&
 673                      md_in_flight(md) && rq->bio && !bio_multiple_segments(rq->bio) &&
 674                      md->last_rq_pos == pos && md->last_rq_rw == rq_data_dir(rq)) ||
 675                     (ti->type->busy && ti->type->busy(ti))) {
 676                         blk_delay_queue(q, 10);
 677                         return;
 678                 }
 679
 680                 dm_start_request(md, rq);
 681
 682                 tio = tio_from_request(rq);
 683                 init_tio(tio, rq, md);
 684                 /* Establish tio->ti before queuing work (map_tio_request) */
 685                 tio->ti = ti;
 686                 kthread_queue_work(&md->kworker, &tio->work);
 687                 BUG_ON(!irqs_disabled());
 688         }
 689 }
 690
 691 /*
 692  * Fully initialize a .request_fn request-based queue.
 693  */
 694 int dm_old_init_request_queue(struct mapped_device *md, struct dm_table *t)
 695 {
 696         struct dm_target *immutable_tgt;
 697
 698         /* Fully initialize the queue */
 699         md->queue->cmd_size = sizeof(struct dm_rq_target_io);
 700         md->queue->rq_alloc_data = md;
 701         md->queue->request_fn = dm_old_request_fn;
 702         md->queue->init_rq_fn = dm_rq_init_rq;
 703
 704         immutable_tgt = dm_table_get_immutable_target(t);
 705         if (immutable_tgt && immutable_tgt->per_io_data_size) {
 706                 /* any target-specific per-io data is immediately after the tio */
 707                 md->queue->cmd_size += immutable_tgt->per_io_data_size;
 708                 md->init_tio_pdu = true;
 709         }
 710         if (blk_init_allocated_queue(md->queue) < 0)
 711                 return -EINVAL;
 712
 713         /* disable dm_old_request_fn's merge heuristic by default */
 714         md->seq_rq_merge_deadline_usecs = 0;
 715
 716         dm_init_normal_md_queue(md);
 717         blk_queue_softirq_done(md->queue, dm_softirq_done);
 718
 719         /* Initialize the request-based DM worker thread */
 720         kthread_init_worker(&md->kworker);
 721         md->kworker_task = kthread_run(kthread_worker_fn, &md->kworker,
 722                                        "kdmwork-%s", dm_device_name(md));
 723         if (IS_ERR(md->kworker_task)) {
 724                 int error = PTR_ERR(md->kworker_task);
 725                 md->kworker_task = NULL;
 726                 return error;
 727         }
 728
 729         return 0;
 730 }
 731
 732 static int dm_mq_init_request(struct blk_mq_tag_set *set, struct request *rq,
 733                 unsigned int hctx_idx, unsigned int numa_node)
 734 {
 735         return __dm_rq_init_rq(set->driver_data, rq);
 736 }
 737
 738 static blk_status_t dm_mq_queue_rq(struct blk_mq_hw_ctx *hctx,
 739                           const struct blk_mq_queue_data *bd)
 740 {
 741         struct request *rq = bd->rq;
 742         struct dm_rq_target_io *tio = blk_mq_rq_to_pdu(rq);
 743         struct mapped_device *md = tio->md;
 744         struct dm_target *ti = md->immutable_target;
 745
 746         if (unlikely(!ti)) {
 747                 int srcu_idx;
 748                 struct dm_table *map = dm_get_live_table(md, &srcu_idx);
 749
 750                 ti = dm_table_find_target(map, 0);
 751                 dm_put_live_table(md, srcu_idx);
 752         }
 753
 754         if (ti->type->busy && ti->type->busy(ti))
 755                 return BLK_STS_RESOURCE;
 756
 757         dm_start_request(md, rq);
 758
 759         /* Init tio using md established in .init_request */
 760         init_tio(tio, rq, md);
 761
 762         /*
 763          * Establish tio->ti before calling map_request().
 764          */
 765         tio->ti = ti;
 766
 767         /* Direct call is fine since .queue_rq allows allocations */
 768         if (map_request(tio) == DM_MAPIO_REQUEUE) {
 769                 /* Undo dm_start_request() before requeuing */
 770                 rq_end_stats(md, rq);
 771                 rq_completed(md, rq_data_dir(rq), false);
 772                 blk_mq_delay_run_hw_queue(hctx, 100/*ms*/);
 773                 return BLK_STS_RESOURCE;
 774         }
 775
 776         return BLK_STS_OK;
 777 }
 778
 779 static const struct blk_mq_ops dm_mq_ops = {
 780         .queue_rq = dm_mq_queue_rq,
 781         .complete = dm_softirq_done,
 782         .init_request = dm_mq_init_request,
 783 };
 784
 785 int dm_mq_init_request_queue(struct mapped_device *md, struct dm_table *t)
 786 {
 787         struct request_queue *q;
 788         struct dm_target *immutable_tgt;
 789         int err;
 790
 791         if (!dm_table_all_blk_mq_devices(t)) {
 792                 DMERR("request-based dm-mq may only be stacked on blk-mq device(s)");
 793                 return -EINVAL;
 794         }
 795
 796         md->tag_set = kzalloc_node(sizeof(struct blk_mq_tag_set), GFP_KERNEL, md->numa_node_id);
 797         if (!md->tag_set)
 798                 return -ENOMEM;
 799
 800         md->tag_set->ops = &dm_mq_ops;
 801         md->tag_set->queue_depth = dm_get_blk_mq_queue_depth();
 802         md->tag_set->numa_node = md->numa_node_id;
 803         md->tag_set->flags = BLK_MQ_F_SHOULD_MERGE | BLK_MQ_F_SG_MERGE;
 804         md->tag_set->nr_hw_queues = dm_get_blk_mq_nr_hw_queues();
 805         md->tag_set->driver_data = md;
 806
 807         md->tag_set->cmd_size = sizeof(struct dm_rq_target_io);
 808         immutable_tgt = dm_table_get_immutable_target(t);
 809         if (immutable_tgt && immutable_tgt->per_io_data_size) {
 810                 /* any target-specific per-io data is immediately after the tio */
 811                 md->tag_set->cmd_size += immutable_tgt->per_io_data_size;
 812                 md->init_tio_pdu = true;
 813         }
 814
 815         err = blk_mq_alloc_tag_set(md->tag_set);
 816         if (err)
 817                 goto out_kfree_tag_set;
 818
 819         q = blk_mq_init_allocated_queue(md->tag_set, md->queue);
 820         if (IS_ERR(q)) {
 821                 err = PTR_ERR(q);
 822                 goto out_tag_set;
 823         }
 824         dm_init_md_queue(md);
 825
 826         return 0;
 827
 828 out_tag_set:
 829         blk_mq_free_tag_set(md->tag_set);
 830 out_kfree_tag_set:
 831         kfree(md->tag_set);
 832
 833         return err;
 834 }
 835
 836 void dm_mq_cleanup_mapped_device(struct mapped_device *md)
 837 {
 838         if (md->tag_set) {
 839                 blk_mq_free_tag_set(md->tag_set);
 840                 kfree(md->tag_set);
 841         }
 842 }
 843
 844 module_param(reserved_rq_based_ios, uint, S_IRUGO | S_IWUSR);
 845 MODULE_PARM_DESC(reserved_rq_based_ios, "Reserved IOs in request-based mempools");
 846
 847 module_param(use_blk_mq, bool, S_IRUGO | S_IWUSR);
 848 MODULE_PARM_DESC(use_blk_mq, "Use block multiqueue for request-based DM devices");
 849
 850 module_param(dm_mq_nr_hw_queues, uint, S_IRUGO | S_IWUSR);
 851 MODULE_PARM_DESC(dm_mq_nr_hw_queues, "Number of hardware queues for request-based dm-mq devices");
 852
 853 module_param(dm_mq_queue_depth, uint, S_IRUGO | S_IWUSR);
 854 MODULE_PARM_DESC(dm_mq_queue_depth, "Queue depth for request-based dm-mq devices");