include/linux/bio.h

   1 /* SPDX-License-Identifier: GPL-2.0 */
   2 /*
   3  * Copyright (C) 2001 Jens Axboe <axboe@suse.de>
   4  */
   5 #ifndef __LINUX_BIO_H
   6 #define __LINUX_BIO_H
   7
   8 #include <linux/mempool.h>
   9 #include <linux/ioprio.h>
  10 /* struct bio, bio_vec and BIO_* flags are defined in blk_types.h */
  11 #include <linux/blk_types.h>
  12 #include <linux/uio.h>
  13
  14 #define BIO_DEBUG
  15
  16 #ifdef BIO_DEBUG
  17 #define BIO_BUG_ON      BUG_ON
  18 #else
  19 #define BIO_BUG_ON
  20 #endif
  21
  22 #define BIO_MAX_VECS            256U
  23
  24 static inline unsigned int bio_max_segs(unsigned int nr_segs)
  25 {
  26         return min(nr_segs, BIO_MAX_VECS);
  27 }
  28
  29 #define bio_prio(bio)                   (bio)->bi_ioprio
  30 #define bio_set_prio(bio, prio)         ((bio)->bi_ioprio = prio)
  31
  32 #define bio_iter_iovec(bio, iter)                               \
  33         bvec_iter_bvec((bio)->bi_io_vec, (iter))
  34
  35 #define bio_iter_page(bio, iter)                                \
  36         bvec_iter_page((bio)->bi_io_vec, (iter))
  37 #define bio_iter_len(bio, iter)                                 \
  38         bvec_iter_len((bio)->bi_io_vec, (iter))
  39 #define bio_iter_offset(bio, iter)                              \
  40         bvec_iter_offset((bio)->bi_io_vec, (iter))
  41
  42 #define bio_page(bio)           bio_iter_page((bio), (bio)->bi_iter)
  43 #define bio_offset(bio)         bio_iter_offset((bio), (bio)->bi_iter)
  44 #define bio_iovec(bio)          bio_iter_iovec((bio), (bio)->bi_iter)
  45
  46 #define bvec_iter_sectors(iter) ((iter).bi_size >> 9)
  47 #define bvec_iter_end_sector(iter) ((iter).bi_sector + bvec_iter_sectors((iter)))
  48
  49 #define bio_sectors(bio)        bvec_iter_sectors((bio)->bi_iter)
  50 #define bio_end_sector(bio)     bvec_iter_end_sector((bio)->bi_iter)
  51
  52 /*
  53  * Return the data direction, READ or WRITE.
  54  */
  55 #define bio_data_dir(bio) \
  56         (op_is_write(bio_op(bio)) ? WRITE : READ)
  57
  58 /*
  59  * Check whether this bio carries any data or not. A NULL bio is allowed.
  60  */
  61 static inline bool bio_has_data(struct bio *bio)
  62 {
  63         if (bio &&
  64             bio->bi_iter.bi_size &&
  65             bio_op(bio) != REQ_OP_DISCARD &&
  66             bio_op(bio) != REQ_OP_SECURE_ERASE &&
  67             bio_op(bio) != REQ_OP_WRITE_ZEROES)
  68                 return true;
  69
  70         return false;
  71 }
  72
  73 static inline bool bio_no_advance_iter(const struct bio *bio)
  74 {
  75         return bio_op(bio) == REQ_OP_DISCARD ||
  76                bio_op(bio) == REQ_OP_SECURE_ERASE ||
  77                bio_op(bio) == REQ_OP_WRITE_SAME ||
  78                bio_op(bio) == REQ_OP_WRITE_ZEROES;
  79 }
  80
  81 static inline bool bio_mergeable(struct bio *bio)
  82 {
  83         if (bio->bi_opf & REQ_NOMERGE_FLAGS)
  84                 return false;
  85
  86         return true;
  87 }
  88
  89 static inline unsigned int bio_cur_bytes(struct bio *bio)
  90 {
  91         if (bio_has_data(bio))
  92                 return bio_iovec(bio).bv_len;
  93         else /* dataless requests such as discard */
  94                 return bio->bi_iter.bi_size;
  95 }
  96
  97 static inline void *bio_data(struct bio *bio)
  98 {
  99         if (bio_has_data(bio))
 100                 return page_address(bio_page(bio)) + bio_offset(bio);
 101
 102         return NULL;
 103 }
 104
 105 /**
 106  * bio_full - check if the bio is full
 107  * @bio:        bio to check
 108  * @len:        length of one segment to be added
 109  *
 110  * Return true if @bio is full and one segment with @len bytes can't be
 111  * added to the bio, otherwise return false
 112  */
 113 static inline bool bio_full(struct bio *bio, unsigned len)
 114 {
 115         if (bio->bi_vcnt >= bio->bi_max_vecs)
 116                 return true;
 117
 118         if (bio->bi_iter.bi_size > UINT_MAX - len)
 119                 return true;
 120
 121         return false;
 122 }
 123
 124 static inline bool bio_next_segment(const struct bio *bio,
 125                                     struct bvec_iter_all *iter)
 126 {
 127         if (iter->idx >= bio->bi_vcnt)
 128                 return false;
 129
 130         bvec_advance(&bio->bi_io_vec[iter->idx], iter);
 131         return true;
 132 }
 133
 134 /*
 135  * drivers should _never_ use the all version - the bio may have been split
 136  * before it got to the driver and the driver won't own all of it
 137  */
 138 #define bio_for_each_segment_all(bvl, bio, iter) \
 139         for (bvl = bvec_init_iter_all(&iter); bio_next_segment((bio), &iter); )
 140
 141 static inline void bio_advance_iter(const struct bio *bio,
 142                                     struct bvec_iter *iter, unsigned int bytes)
 143 {
 144         iter->bi_sector += bytes >> 9;
 145
 146         if (bio_no_advance_iter(bio))
 147                 iter->bi_size -= bytes;
 148         else
 149                 bvec_iter_advance(bio->bi_io_vec, iter, bytes);
 150                 /* TODO: It is reasonable to complete bio with error here. */
 151 }
 152
 153 /* @bytes should be less or equal to bvec[i->bi_idx].bv_len */
 154 static inline void bio_advance_iter_single(const struct bio *bio,
 155                                            struct bvec_iter *iter,
 156                                            unsigned int bytes)
 157 {
 158         iter->bi_sector += bytes >> 9;
 159
 160         if (bio_no_advance_iter(bio))
 161                 iter->bi_size -= bytes;
 162         else
 163                 bvec_iter_advance_single(bio->bi_io_vec, iter, bytes);
 164 }
 165
 166 #define __bio_for_each_segment(bvl, bio, iter, start)                   \
 167         for (iter = (start);                                            \
 168              (iter).bi_size &&                                          \
 169                 ((bvl = bio_iter_iovec((bio), (iter))), 1);             \
 170              bio_advance_iter_single((bio), &(iter), (bvl).bv_len))
 171
 172 #define bio_for_each_segment(bvl, bio, iter)                            \
 173         __bio_for_each_segment(bvl, bio, iter, (bio)->bi_iter)
 174
 175 #define __bio_for_each_bvec(bvl, bio, iter, start)              \
 176         for (iter = (start);                                            \
 177              (iter).bi_size &&                                          \
 178                 ((bvl = mp_bvec_iter_bvec((bio)->bi_io_vec, (iter))), 1); \
 179              bio_advance_iter_single((bio), &(iter), (bvl).bv_len))
 180
 181 /* iterate over multi-page bvec */
 182 #define bio_for_each_bvec(bvl, bio, iter)                       \
 183         __bio_for_each_bvec(bvl, bio, iter, (bio)->bi_iter)
 184
 185 /*
 186  * Iterate over all multi-page bvecs. Drivers shouldn't use this version for the
 187  * same reasons as bio_for_each_segment_all().
 188  */
 189 #define bio_for_each_bvec_all(bvl, bio, i)              \
 190         for (i = 0, bvl = bio_first_bvec_all(bio);      \
 191              i < (bio)->bi_vcnt; i++, bvl++)            \
 192
 193 #define bio_iter_last(bvec, iter) ((iter).bi_size == (bvec).bv_len)
 194
 195 static inline unsigned bio_segments(struct bio *bio)
 196 {
 197         unsigned segs = 0;
 198         struct bio_vec bv;
 199         struct bvec_iter iter;
 200
 201         /*
 202          * We special case discard/write same/write zeroes, because they
 203          * interpret bi_size differently:
 204          */
 205
 206         switch (bio_op(bio)) {
 207         case REQ_OP_DISCARD:
 208         case REQ_OP_SECURE_ERASE:
 209         case REQ_OP_WRITE_ZEROES:
 210                 return 0;
 211         case REQ_OP_WRITE_SAME:
 212                 return 1;
 213         default:
 214                 break;
 215         }
 216
 217         bio_for_each_segment(bv, bio, iter)
 218                 segs++;
 219
 220         return segs;
 221 }
 222
 223 /*
 224  * get a reference to a bio, so it won't disappear. the intended use is
 225  * something like:
 226  *
 227  * bio_get(bio);
 228  * submit_bio(rw, bio);
 229  * if (bio->bi_flags ...)
 230  *      do_something
 231  * bio_put(bio);
 232  *
 233  * without the bio_get(), it could potentially complete I/O before submit_bio
 234  * returns. and then bio would be freed memory when if (bio->bi_flags ...)
 235  * runs
 236  */
 237 static inline void bio_get(struct bio *bio)
 238 {
 239         bio->bi_flags |= (1 << BIO_REFFED);
 240         smp_mb__before_atomic();
 241         atomic_inc(&bio->__bi_cnt);
 242 }
 243
 244 static inline void bio_cnt_set(struct bio *bio, unsigned int count)
 245 {
 246         if (count != 1) {
 247                 bio->bi_flags |= (1 << BIO_REFFED);
 248                 smp_mb();
 249         }
 250         atomic_set(&bio->__bi_cnt, count);
 251 }
 252
 253 static inline bool bio_flagged(struct bio *bio, unsigned int bit)
 254 {
 255         return (bio->bi_flags & (1U << bit)) != 0;
 256 }
 257
 258 static inline void bio_set_flag(struct bio *bio, unsigned int bit)
 259 {
 260         bio->bi_flags |= (1U << bit);
 261 }
 262
 263 static inline void bio_clear_flag(struct bio *bio, unsigned int bit)
 264 {
 265         bio->bi_flags &= ~(1U << bit);
 266 }
 267
 268 static inline void bio_get_first_bvec(struct bio *bio, struct bio_vec *bv)
 269 {
 270         *bv = mp_bvec_iter_bvec(bio->bi_io_vec, bio->bi_iter);
 271 }
 272
 273 static inline void bio_get_last_bvec(struct bio *bio, struct bio_vec *bv)
 274 {
 275         struct bvec_iter iter = bio->bi_iter;
 276         int idx;
 277
 278         bio_get_first_bvec(bio, bv);
 279         if (bv->bv_len == bio->bi_iter.bi_size)
 280                 return;         /* this bio only has a single bvec */
 281
 282         bio_advance_iter(bio, &iter, iter.bi_size);
 283
 284         if (!iter.bi_bvec_done)
 285                 idx = iter.bi_idx - 1;
 286         else    /* in the middle of bvec */
 287                 idx = iter.bi_idx;
 288
 289         *bv = bio->bi_io_vec[idx];
 290
 291         /*
 292          * iter.bi_bvec_done records actual length of the last bvec
 293          * if this bio ends in the middle of one io vector
 294          */
 295         if (iter.bi_bvec_done)
 296                 bv->bv_len = iter.bi_bvec_done;
 297 }
 298
 299 static inline struct bio_vec *bio_first_bvec_all(struct bio *bio)
 300 {
 301         WARN_ON_ONCE(bio_flagged(bio, BIO_CLONED));
 302         return bio->bi_io_vec;
 303 }
 304
 305 static inline struct page *bio_first_page_all(struct bio *bio)
 306 {
 307         return bio_first_bvec_all(bio)->bv_page;
 308 }
 309
 310 static inline struct bio_vec *bio_last_bvec_all(struct bio *bio)
 311 {
 312         WARN_ON_ONCE(bio_flagged(bio, BIO_CLONED));
 313         return &bio->bi_io_vec[bio->bi_vcnt - 1];
 314 }
 315
 316 enum bip_flags {
 317         BIP_BLOCK_INTEGRITY     = 1 << 0, /* block layer owns integrity data */
 318         BIP_MAPPED_INTEGRITY    = 1 << 1, /* ref tag has been remapped */
 319         BIP_CTRL_NOCHECK        = 1 << 2, /* disable HBA integrity checking */
 320         BIP_DISK_NOCHECK        = 1 << 3, /* disable disk integrity checking */
 321         BIP_IP_CHECKSUM         = 1 << 4, /* IP checksum */
 322 };
 323
 324 /*
 325  * bio integrity payload
 326  */
 327 struct bio_integrity_payload {
 328         struct bio              *bip_bio;       /* parent bio */
 329
 330         struct bvec_iter        bip_iter;
 331
 332         unsigned short          bip_vcnt;       /* # of integrity bio_vecs */
 333         unsigned short          bip_max_vcnt;   /* integrity bio_vec slots */
 334         unsigned short          bip_flags;      /* control flags */
 335
 336         struct bvec_iter        bio_iter;       /* for rewinding parent bio */
 337
 338         struct work_struct      bip_work;       /* I/O completion */
 339
 340         struct bio_vec          *bip_vec;
 341         struct bio_vec          bip_inline_vecs[];/* embedded bvec array */
 342 };
 343
 344 #if defined(CONFIG_BLK_DEV_INTEGRITY)
 345
 346 static inline struct bio_integrity_payload *bio_integrity(struct bio *bio)
 347 {
 348         if (bio->bi_opf & REQ_INTEGRITY)
 349                 return bio->bi_integrity;
 350
 351         return NULL;
 352 }
 353
 354 static inline bool bio_integrity_flagged(struct bio *bio, enum bip_flags flag)
 355 {
 356         struct bio_integrity_payload *bip = bio_integrity(bio);
 357
 358         if (bip)
 359                 return bip->bip_flags & flag;
 360
 361         return false;
 362 }
 363
 364 static inline sector_t bip_get_seed(struct bio_integrity_payload *bip)
 365 {
 366         return bip->bip_iter.bi_sector;
 367 }
 368
 369 static inline void bip_set_seed(struct bio_integrity_payload *bip,
 370                                 sector_t seed)
 371 {
 372         bip->bip_iter.bi_sector = seed;
 373 }
 374
 375 #endif /* CONFIG_BLK_DEV_INTEGRITY */
 376
 377 void bio_trim(struct bio *bio, sector_t offset, sector_t size);
 378 extern struct bio *bio_split(struct bio *bio, int sectors,
 379                              gfp_t gfp, struct bio_set *bs);
 380
 381 /**
 382  * bio_next_split - get next @sectors from a bio, splitting if necessary
 383  * @bio:        bio to split
 384  * @sectors:    number of sectors to split from the front of @bio
 385  * @gfp:        gfp mask
 386  * @bs:         bio set to allocate from
 387  *
 388  * Returns a bio representing the next @sectors of @bio - if the bio is smaller
 389  * than @sectors, returns the original bio unchanged.
 390  */
 391 static inline struct bio *bio_next_split(struct bio *bio, int sectors,
 392                                          gfp_t gfp, struct bio_set *bs)
 393 {
 394         if (sectors >= bio_sectors(bio))
 395                 return bio;
 396
 397         return bio_split(bio, sectors, gfp, bs);
 398 }
 399
 400 enum {
 401         BIOSET_NEED_BVECS = BIT(0),
 402         BIOSET_NEED_RESCUER = BIT(1),
 403         BIOSET_PERCPU_CACHE = BIT(2),
 404 };
 405 extern int bioset_init(struct bio_set *, unsigned int, unsigned int, int flags);
 406 extern void bioset_exit(struct bio_set *);
 407 extern int biovec_init_pool(mempool_t *pool, int pool_entries);
 408 extern int bioset_init_from_src(struct bio_set *bs, struct bio_set *src);
 409
 410 struct bio *bio_alloc_bioset(gfp_t gfp, unsigned short nr_iovecs,
 411                 struct bio_set *bs);
 412 struct bio *bio_alloc_kiocb(struct kiocb *kiocb, unsigned short nr_vecs,
 413                 struct bio_set *bs);
 414 struct bio *bio_kmalloc(gfp_t gfp_mask, unsigned short nr_iovecs);
 415 extern void bio_put(struct bio *);
 416
 417 extern void __bio_clone_fast(struct bio *, struct bio *);
 418 extern struct bio *bio_clone_fast(struct bio *, gfp_t, struct bio_set *);
 419
 420 extern struct bio_set fs_bio_set;
 421
 422 static inline struct bio *bio_alloc(gfp_t gfp_mask, unsigned short nr_iovecs)
 423 {
 424         return bio_alloc_bioset(gfp_mask, nr_iovecs, &fs_bio_set);
 425 }
 426
 427 extern blk_qc_t submit_bio(struct bio *);
 428
 429 extern void bio_endio(struct bio *);
 430
 431 static inline void bio_io_error(struct bio *bio)
 432 {
 433         bio->bi_status = BLK_STS_IOERR;
 434         bio_endio(bio);
 435 }
 436
 437 static inline void bio_wouldblock_error(struct bio *bio)
 438 {
 439         bio_set_flag(bio, BIO_QUIET);
 440         bio->bi_status = BLK_STS_AGAIN;
 441         bio_endio(bio);
 442 }
 443
 444 /*
 445  * Calculate number of bvec segments that should be allocated to fit data
 446  * pointed by @iter. If @iter is backed by bvec it's going to be reused
 447  * instead of allocating a new one.
 448  */
 449 static inline int bio_iov_vecs_to_alloc(struct iov_iter *iter, int max_segs)
 450 {
 451         if (iov_iter_is_bvec(iter))
 452                 return 0;
 453         return iov_iter_npages(iter, max_segs);
 454 }
 455
 456 struct request_queue;
 457
 458 extern int submit_bio_wait(struct bio *bio);
 459 extern void bio_advance(struct bio *, unsigned);
 460
 461 extern void bio_init(struct bio *bio, struct bio_vec *table,
 462                      unsigned short max_vecs);
 463 extern void bio_uninit(struct bio *);
 464 extern void bio_reset(struct bio *);
 465 void bio_chain(struct bio *, struct bio *);
 466
 467 extern int bio_add_page(struct bio *, struct page *, unsigned int,unsigned int);
 468 extern int bio_add_pc_page(struct request_queue *, struct bio *, struct page *,
 469                            unsigned int, unsigned int);
 470 int bio_add_zone_append_page(struct bio *bio, struct page *page,
 471                              unsigned int len, unsigned int offset);
 472 bool __bio_try_merge_page(struct bio *bio, struct page *page,
 473                 unsigned int len, unsigned int off, bool *same_page);
 474 void __bio_add_page(struct bio *bio, struct page *page,
 475                 unsigned int len, unsigned int off);
 476 int bio_iov_iter_get_pages(struct bio *bio, struct iov_iter *iter);
 477 void bio_release_pages(struct bio *bio, bool mark_dirty);
 478 extern void bio_set_pages_dirty(struct bio *bio);
 479 extern void bio_check_pages_dirty(struct bio *bio);
 480
 481 extern void bio_copy_data_iter(struct bio *dst, struct bvec_iter *dst_iter,
 482                                struct bio *src, struct bvec_iter *src_iter);
 483 extern void bio_copy_data(struct bio *dst, struct bio *src);
 484 extern void bio_free_pages(struct bio *bio);
 485 void bio_truncate(struct bio *bio, unsigned new_size);
 486 void guard_bio_eod(struct bio *bio);
 487 void zero_fill_bio(struct bio *bio);
 488
 489 extern const char *bio_devname(struct bio *bio, char *buffer);
 490
 491 #define bio_set_dev(bio, bdev)                          \
 492 do {                                                    \
 493         bio_clear_flag(bio, BIO_REMAPPED);              \
 494         if ((bio)->bi_bdev != (bdev))                   \
 495                 bio_clear_flag(bio, BIO_THROTTLED);     \
 496         (bio)->bi_bdev = (bdev);                        \
 497         bio_associate_blkg(bio);                        \
 498 } while (0)
 499
 500 #define bio_copy_dev(dst, src)                  \
 501 do {                                            \
 502         bio_clear_flag(dst, BIO_REMAPPED);              \
 503         (dst)->bi_bdev = (src)->bi_bdev;        \
 504         bio_clone_blkg_association(dst, src);   \
 505 } while (0)
 506
 507 #define bio_dev(bio) \
 508         disk_devt((bio)->bi_bdev->bd_disk)
 509
 510 #ifdef CONFIG_BLK_CGROUP
 511 void bio_associate_blkg(struct bio *bio);
 512 void bio_associate_blkg_from_css(struct bio *bio,
 513                                  struct cgroup_subsys_state *css);
 514 void bio_clone_blkg_association(struct bio *dst, struct bio *src);
 515 #else   /* CONFIG_BLK_CGROUP */
 516 static inline void bio_associate_blkg(struct bio *bio) { }
 517 static inline void bio_associate_blkg_from_css(struct bio *bio,
 518                                                struct cgroup_subsys_state *css)
 519 { }
 520 static inline void bio_clone_blkg_association(struct bio *dst,
 521                                               struct bio *src) { }
 522 #endif  /* CONFIG_BLK_CGROUP */
 523
 524 /*
 525  * BIO list management for use by remapping drivers (e.g. DM or MD) and loop.
 526  *
 527  * A bio_list anchors a singly-linked list of bios chained through the bi_next
 528  * member of the bio.  The bio_list also caches the last list member to allow
 529  * fast access to the tail.
 530  */
 531 struct bio_list {
 532         struct bio *head;
 533         struct bio *tail;
 534 };
 535
 536 static inline int bio_list_empty(const struct bio_list *bl)
 537 {
 538         return bl->head == NULL;
 539 }
 540
 541 static inline void bio_list_init(struct bio_list *bl)
 542 {
 543         bl->head = bl->tail = NULL;
 544 }
 545
 546 #define BIO_EMPTY_LIST  { NULL, NULL }
 547
 548 #define bio_list_for_each(bio, bl) \
 549         for (bio = (bl)->head; bio; bio = bio->bi_next)
 550
 551 static inline unsigned bio_list_size(const struct bio_list *bl)
 552 {
 553         unsigned sz = 0;
 554         struct bio *bio;
 555
 556         bio_list_for_each(bio, bl)
 557                 sz++;
 558
 559         return sz;
 560 }
 561
 562 static inline void bio_list_add(struct bio_list *bl, struct bio *bio)
 563 {
 564         bio->bi_next = NULL;
 565
 566         if (bl->tail)
 567                 bl->tail->bi_next = bio;
 568         else
 569                 bl->head = bio;
 570
 571         bl->tail = bio;
 572 }
 573
 574 static inline void bio_list_add_head(struct bio_list *bl, struct bio *bio)
 575 {
 576         bio->bi_next = bl->head;
 577
 578         bl->head = bio;
 579
 580         if (!bl->tail)
 581                 bl->tail = bio;
 582 }
 583
 584 static inline void bio_list_merge(struct bio_list *bl, struct bio_list *bl2)
 585 {
 586         if (!bl2->head)
 587                 return;
 588
 589         if (bl->tail)
 590                 bl->tail->bi_next = bl2->head;
 591         else
 592                 bl->head = bl2->head;
 593
 594         bl->tail = bl2->tail;
 595 }
 596
 597 static inline void bio_list_merge_head(struct bio_list *bl,
 598                                        struct bio_list *bl2)
 599 {
 600         if (!bl2->head)
 601                 return;
 602
 603         if (bl->head)
 604                 bl2->tail->bi_next = bl->head;
 605         else
 606                 bl->tail = bl2->tail;
 607
 608         bl->head = bl2->head;
 609 }
 610
 611 static inline struct bio *bio_list_peek(struct bio_list *bl)
 612 {
 613         return bl->head;
 614 }
 615
 616 static inline struct bio *bio_list_pop(struct bio_list *bl)
 617 {
 618         struct bio *bio = bl->head;
 619
 620         if (bio) {
 621                 bl->head = bl->head->bi_next;
 622                 if (!bl->head)
 623                         bl->tail = NULL;
 624
 625                 bio->bi_next = NULL;
 626         }
 627
 628         return bio;
 629 }
 630
 631 static inline struct bio *bio_list_get(struct bio_list *bl)
 632 {
 633         struct bio *bio = bl->head;
 634
 635         bl->head = bl->tail = NULL;
 636
 637         return bio;
 638 }
 639
 640 /*
 641  * Increment chain count for the bio. Make sure the CHAIN flag update
 642  * is visible before the raised count.
 643  */
 644 static inline void bio_inc_remaining(struct bio *bio)
 645 {
 646         bio_set_flag(bio, BIO_CHAIN);
 647         smp_mb__before_atomic();
 648         atomic_inc(&bio->__bi_remaining);
 649 }
 650
 651 /*
 652  * bio_set is used to allow other portions of the IO system to
 653  * allocate their own private memory pools for bio and iovec structures.
 654  * These memory pools in turn all allocate from the bio_slab
 655  * and the bvec_slabs[].
 656  */
 657 #define BIO_POOL_SIZE 2
 658
 659 struct bio_set {
 660         struct kmem_cache *bio_slab;
 661         unsigned int front_pad;
 662
 663         /*
 664          * per-cpu bio alloc cache
 665          */
 666         struct bio_alloc_cache __percpu *cache;
 667
 668         mempool_t bio_pool;
 669         mempool_t bvec_pool;
 670 #if defined(CONFIG_BLK_DEV_INTEGRITY)
 671         mempool_t bio_integrity_pool;
 672         mempool_t bvec_integrity_pool;
 673 #endif
 674
 675         unsigned int back_pad;
 676         /*
 677          * Deadlock avoidance for stacking block drivers: see comments in
 678          * bio_alloc_bioset() for details
 679          */
 680         spinlock_t              rescue_lock;
 681         struct bio_list         rescue_list;
 682         struct work_struct      rescue_work;
 683         struct workqueue_struct *rescue_workqueue;
 684
 685         /*
 686          * Hot un-plug notifier for the per-cpu cache, if used
 687          */
 688         struct hlist_node cpuhp_dead;
 689 };
 690
 691 static inline bool bioset_initialized(struct bio_set *bs)
 692 {
 693         return bs->bio_slab != NULL;
 694 }
 695
 696 #if defined(CONFIG_BLK_DEV_INTEGRITY)
 697
 698 #define bip_for_each_vec(bvl, bip, iter)                                \
 699         for_each_bvec(bvl, (bip)->bip_vec, iter, (bip)->bip_iter)
 700
 701 #define bio_for_each_integrity_vec(_bvl, _bio, _iter)                   \
 702         for_each_bio(_bio)                                              \
 703                 bip_for_each_vec(_bvl, _bio->bi_integrity, _iter)
 704
 705 extern struct bio_integrity_payload *bio_integrity_alloc(struct bio *, gfp_t, unsigned int);
 706 extern int bio_integrity_add_page(struct bio *, struct page *, unsigned int, unsigned int);
 707 extern bool bio_integrity_prep(struct bio *);
 708 extern void bio_integrity_advance(struct bio *, unsigned int);
 709 extern void bio_integrity_trim(struct bio *);
 710 extern int bio_integrity_clone(struct bio *, struct bio *, gfp_t);
 711 extern int bioset_integrity_create(struct bio_set *, int);
 712 extern void bioset_integrity_free(struct bio_set *);
 713 extern void bio_integrity_init(void);
 714
 715 #else /* CONFIG_BLK_DEV_INTEGRITY */
 716
 717 static inline void *bio_integrity(struct bio *bio)
 718 {
 719         return NULL;
 720 }
 721
 722 static inline int bioset_integrity_create(struct bio_set *bs, int pool_size)
 723 {
 724         return 0;
 725 }
 726
 727 static inline void bioset_integrity_free (struct bio_set *bs)
 728 {
 729         return;
 730 }
 731
 732 static inline bool bio_integrity_prep(struct bio *bio)
 733 {
 734         return true;
 735 }
 736
 737 static inline int bio_integrity_clone(struct bio *bio, struct bio *bio_src,
 738                                       gfp_t gfp_mask)
 739 {
 740         return 0;
 741 }
 742
 743 static inline void bio_integrity_advance(struct bio *bio,
 744                                          unsigned int bytes_done)
 745 {
 746         return;
 747 }
 748
 749 static inline void bio_integrity_trim(struct bio *bio)
 750 {
 751         return;
 752 }
 753
 754 static inline void bio_integrity_init(void)
 755 {
 756         return;
 757 }
 758
 759 static inline bool bio_integrity_flagged(struct bio *bio, enum bip_flags flag)
 760 {
 761         return false;
 762 }
 763
 764 static inline void *bio_integrity_alloc(struct bio * bio, gfp_t gfp,
 765                                                                 unsigned int nr)
 766 {
 767         return ERR_PTR(-EINVAL);
 768 }
 769
 770 static inline int bio_integrity_add_page(struct bio *bio, struct page *page,
 771                                         unsigned int len, unsigned int offset)
 772 {
 773         return 0;
 774 }
 775
 776 #endif /* CONFIG_BLK_DEV_INTEGRITY */
 777
 778 /*
 779  * Mark a bio as polled. Note that for async polled IO, the caller must
 780  * expect -EWOULDBLOCK if we cannot allocate a request (or other resources).
 781  * We cannot block waiting for requests on polled IO, as those completions
 782  * must be found by the caller. This is different than IRQ driven IO, where
 783  * it's safe to wait for IO to complete.
 784  */
 785 static inline void bio_set_polled(struct bio *bio, struct kiocb *kiocb)
 786 {
 787         bio->bi_opf |= REQ_HIPRI;
 788         if (!is_sync_kiocb(kiocb))
 789                 bio->bi_opf |= REQ_NOWAIT;
 790 }
 791
 792 struct bio *blk_next_bio(struct bio *bio, unsigned int nr_pages, gfp_t gfp);
 793
 794 #endif /* __LINUX_BIO_H */