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/highmem.h>
   9 #include <linux/mempool.h>
  10 #include <linux/ioprio.h>
  11 /* struct bio, bio_vec and BIO_* flags are defined in blk_types.h */
  12 #include <linux/blk_types.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_PAGES           256
  23
  24 #define bio_prio(bio)                   (bio)->bi_ioprio
  25 #define bio_set_prio(bio, prio)         ((bio)->bi_ioprio = prio)
  26
  27 #define bio_iter_iovec(bio, iter)                               \
  28         bvec_iter_bvec((bio)->bi_io_vec, (iter))
  29
  30 #define bio_iter_page(bio, iter)                                \
  31         bvec_iter_page((bio)->bi_io_vec, (iter))
  32 #define bio_iter_len(bio, iter)                                 \
  33         bvec_iter_len((bio)->bi_io_vec, (iter))
  34 #define bio_iter_offset(bio, iter)                              \
  35         bvec_iter_offset((bio)->bi_io_vec, (iter))
  36
  37 #define bio_page(bio)           bio_iter_page((bio), (bio)->bi_iter)
  38 #define bio_offset(bio)         bio_iter_offset((bio), (bio)->bi_iter)
  39 #define bio_iovec(bio)          bio_iter_iovec((bio), (bio)->bi_iter)
  40
  41 #define bio_multiple_segments(bio)                              \
  42         ((bio)->bi_iter.bi_size != bio_iovec(bio).bv_len)
  43
  44 #define bvec_iter_sectors(iter) ((iter).bi_size >> 9)
  45 #define bvec_iter_end_sector(iter) ((iter).bi_sector + bvec_iter_sectors((iter)))
  46
  47 #define bio_sectors(bio)        bvec_iter_sectors((bio)->bi_iter)
  48 #define bio_end_sector(bio)     bvec_iter_end_sector((bio)->bi_iter)
  49
  50 /*
  51  * Return the data direction, READ or WRITE.
  52  */
  53 #define bio_data_dir(bio) \
  54         (op_is_write(bio_op(bio)) ? WRITE : READ)
  55
  56 /*
  57  * Check whether this bio carries any data or not. A NULL bio is allowed.
  58  */
  59 static inline bool bio_has_data(struct bio *bio)
  60 {
  61         if (bio &&
  62             bio->bi_iter.bi_size &&
  63             bio_op(bio) != REQ_OP_DISCARD &&
  64             bio_op(bio) != REQ_OP_SECURE_ERASE &&
  65             bio_op(bio) != REQ_OP_WRITE_ZEROES)
  66                 return true;
  67
  68         return false;
  69 }
  70
  71 static inline bool bio_no_advance_iter(const struct bio *bio)
  72 {
  73         return bio_op(bio) == REQ_OP_DISCARD ||
  74                bio_op(bio) == REQ_OP_SECURE_ERASE ||
  75                bio_op(bio) == REQ_OP_WRITE_SAME ||
  76                bio_op(bio) == REQ_OP_WRITE_ZEROES;
  77 }
  78
  79 static inline bool bio_mergeable(struct bio *bio)
  80 {
  81         if (bio->bi_opf & REQ_NOMERGE_FLAGS)
  82                 return false;
  83
  84         return true;
  85 }
  86
  87 static inline unsigned int bio_cur_bytes(struct bio *bio)
  88 {
  89         if (bio_has_data(bio))
  90                 return bio_iovec(bio).bv_len;
  91         else /* dataless requests such as discard */
  92                 return bio->bi_iter.bi_size;
  93 }
  94
  95 static inline void *bio_data(struct bio *bio)
  96 {
  97         if (bio_has_data(bio))
  98                 return page_address(bio_page(bio)) + bio_offset(bio);
  99
 100         return NULL;
 101 }
 102
 103 /**
 104  * bio_full - check if the bio is full
 105  * @bio:        bio to check
 106  * @len:        length of one segment to be added
 107  *
 108  * Return true if @bio is full and one segment with @len bytes can't be
 109  * added to the bio, otherwise return false
 110  */
 111 static inline bool bio_full(struct bio *bio, unsigned len)
 112 {
 113         if (bio->bi_vcnt >= bio->bi_max_vecs)
 114                 return true;
 115
 116         if (bio->bi_iter.bi_size > UINT_MAX - len)
 117                 return true;
 118
 119         return false;
 120 }
 121
 122 static inline bool bio_next_segment(const struct bio *bio,
 123                                     struct bvec_iter_all *iter)
 124 {
 125         if (iter->idx >= bio->bi_vcnt)
 126                 return false;
 127
 128         bvec_advance(&bio->bi_io_vec[iter->idx], iter);
 129         return true;
 130 }
 131
 132 /*
 133  * drivers should _never_ use the all version - the bio may have been split
 134  * before it got to the driver and the driver won't own all of it
 135  */
 136 #define bio_for_each_segment_all(bvl, bio, iter) \
 137         for (bvl = bvec_init_iter_all(&iter); bio_next_segment((bio), &iter); )
 138
 139 static inline void bio_advance_iter(const struct bio *bio,
 140                                     struct bvec_iter *iter, unsigned int bytes)
 141 {
 142         iter->bi_sector += bytes >> 9;
 143
 144         if (bio_no_advance_iter(bio))
 145                 iter->bi_size -= bytes;
 146         else
 147                 bvec_iter_advance(bio->bi_io_vec, iter, bytes);
 148                 /* TODO: It is reasonable to complete bio with error here. */
 149 }
 150
 151 /* @bytes should be less or equal to bvec[i->bi_idx].bv_len */
 152 static inline void bio_advance_iter_single(const struct bio *bio,
 153                                            struct bvec_iter *iter,
 154                                            unsigned int bytes)
 155 {
 156         iter->bi_sector += bytes >> 9;
 157
 158         if (bio_no_advance_iter(bio))
 159                 iter->bi_size -= bytes;
 160         else
 161                 bvec_iter_advance_single(bio->bi_io_vec, iter, bytes);
 162 }
 163
 164 #define __bio_for_each_segment(bvl, bio, iter, start)                   \
 165         for (iter = (start);                                            \
 166              (iter).bi_size &&                                          \
 167                 ((bvl = bio_iter_iovec((bio), (iter))), 1);             \
 168              bio_advance_iter_single((bio), &(iter), (bvl).bv_len))
 169
 170 #define bio_for_each_segment(bvl, bio, iter)                            \
 171         __bio_for_each_segment(bvl, bio, iter, (bio)->bi_iter)
 172
 173 #define __bio_for_each_bvec(bvl, bio, iter, start)              \
 174         for (iter = (start);                                            \
 175              (iter).bi_size &&                                          \
 176                 ((bvl = mp_bvec_iter_bvec((bio)->bi_io_vec, (iter))), 1); \
 177              bio_advance_iter_single((bio), &(iter), (bvl).bv_len))
 178
 179 /* iterate over multi-page bvec */
 180 #define bio_for_each_bvec(bvl, bio, iter)                       \
 181         __bio_for_each_bvec(bvl, bio, iter, (bio)->bi_iter)
 182
 183 /*
 184  * Iterate over all multi-page bvecs. Drivers shouldn't use this version for the
 185  * same reasons as bio_for_each_segment_all().
 186  */
 187 #define bio_for_each_bvec_all(bvl, bio, i)              \
 188         for (i = 0, bvl = bio_first_bvec_all(bio);      \
 189              i < (bio)->bi_vcnt; i++, bvl++)            \
 190
 191 #define bio_iter_last(bvec, iter) ((iter).bi_size == (bvec).bv_len)
 192
 193 static inline unsigned bio_segments(struct bio *bio)
 194 {
 195         unsigned segs = 0;
 196         struct bio_vec bv;
 197         struct bvec_iter iter;
 198
 199         /*
 200          * We special case discard/write same/write zeroes, because they
 201          * interpret bi_size differently:
 202          */
 203
 204         switch (bio_op(bio)) {
 205         case REQ_OP_DISCARD:
 206         case REQ_OP_SECURE_ERASE:
 207         case REQ_OP_WRITE_ZEROES:
 208                 return 0;
 209         case REQ_OP_WRITE_SAME:
 210                 return 1;
 211         default:
 212                 break;
 213         }
 214
 215         bio_for_each_segment(bv, bio, iter)
 216                 segs++;
 217
 218         return segs;
 219 }
 220
 221 /*
 222  * get a reference to a bio, so it won't disappear. the intended use is
 223  * something like:
 224  *
 225  * bio_get(bio);
 226  * submit_bio(rw, bio);
 227  * if (bio->bi_flags ...)
 228  *      do_something
 229  * bio_put(bio);
 230  *
 231  * without the bio_get(), it could potentially complete I/O before submit_bio
 232  * returns. and then bio would be freed memory when if (bio->bi_flags ...)
 233  * runs
 234  */
 235 static inline void bio_get(struct bio *bio)
 236 {
 237         bio->bi_flags |= (1 << BIO_REFFED);
 238         smp_mb__before_atomic();
 239         atomic_inc(&bio->__bi_cnt);
 240 }
 241
 242 static inline void bio_cnt_set(struct bio *bio, unsigned int count)
 243 {
 244         if (count != 1) {
 245                 bio->bi_flags |= (1 << BIO_REFFED);
 246                 smp_mb();
 247         }
 248         atomic_set(&bio->__bi_cnt, count);
 249 }
 250
 251 static inline bool bio_flagged(struct bio *bio, unsigned int bit)
 252 {
 253         return (bio->bi_flags & (1U << bit)) != 0;
 254 }
 255
 256 static inline void bio_set_flag(struct bio *bio, unsigned int bit)
 257 {
 258         bio->bi_flags |= (1U << bit);
 259 }
 260
 261 static inline void bio_clear_flag(struct bio *bio, unsigned int bit)
 262 {
 263         bio->bi_flags &= ~(1U << bit);
 264 }
 265
 266 static inline void bio_get_first_bvec(struct bio *bio, struct bio_vec *bv)
 267 {
 268         *bv = bio_iovec(bio);
 269 }
 270
 271 static inline void bio_get_last_bvec(struct bio *bio, struct bio_vec *bv)
 272 {
 273         struct bvec_iter iter = bio->bi_iter;
 274         int idx;
 275
 276         if (unlikely(!bio_multiple_segments(bio))) {
 277                 *bv = bio_iovec(bio);
 278                 return;
 279         }
 280
 281         bio_advance_iter(bio, &iter, iter.bi_size);
 282
 283         if (!iter.bi_bvec_done)
 284                 idx = iter.bi_idx - 1;
 285         else    /* in the middle of bvec */
 286                 idx = iter.bi_idx;
 287
 288         *bv = bio->bi_io_vec[idx];
 289
 290         /*
 291          * iter.bi_bvec_done records actual length of the last bvec
 292          * if this bio ends in the middle of one io vector
 293          */
 294         if (iter.bi_bvec_done)
 295                 bv->bv_len = iter.bi_bvec_done;
 296 }
 297
 298 static inline struct bio_vec *bio_first_bvec_all(struct bio *bio)
 299 {
 300         WARN_ON_ONCE(bio_flagged(bio, BIO_CLONED));
 301         return bio->bi_io_vec;
 302 }
 303
 304 static inline struct page *bio_first_page_all(struct bio *bio)
 305 {
 306         return bio_first_bvec_all(bio)->bv_page;
 307 }
 308
 309 static inline struct bio_vec *bio_last_bvec_all(struct bio *bio)
 310 {
 311         WARN_ON_ONCE(bio_flagged(bio, BIO_CLONED));
 312         return &bio->bi_io_vec[bio->bi_vcnt - 1];
 313 }
 314
 315 enum bip_flags {
 316         BIP_BLOCK_INTEGRITY     = 1 << 0, /* block layer owns integrity data */
 317         BIP_MAPPED_INTEGRITY    = 1 << 1, /* ref tag has been remapped */
 318         BIP_CTRL_NOCHECK        = 1 << 2, /* disable HBA integrity checking */
 319         BIP_DISK_NOCHECK        = 1 << 3, /* disable disk integrity checking */
 320         BIP_IP_CHECKSUM         = 1 << 4, /* IP checksum */
 321 };
 322
 323 /*
 324  * bio integrity payload
 325  */
 326 struct bio_integrity_payload {
 327         struct bio              *bip_bio;       /* parent bio */
 328
 329         struct bvec_iter        bip_iter;
 330
 331         unsigned short          bip_slab;       /* slab the bip came from */
 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 extern void bio_trim(struct bio *bio, int offset, int 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 };
 404 extern int bioset_init(struct bio_set *, unsigned int, unsigned int, int flags);
 405 extern void bioset_exit(struct bio_set *);
 406 extern int biovec_init_pool(mempool_t *pool, int pool_entries);
 407 extern int bioset_init_from_src(struct bio_set *bs, struct bio_set *src);
 408
 409 extern struct bio *bio_alloc_bioset(gfp_t, unsigned int, struct bio_set *);
 410 extern void bio_put(struct bio *);
 411
 412 extern void __bio_clone_fast(struct bio *, struct bio *);
 413 extern struct bio *bio_clone_fast(struct bio *, gfp_t, struct bio_set *);
 414
 415 extern struct bio_set fs_bio_set;
 416
 417 static inline struct bio *bio_alloc(gfp_t gfp_mask, unsigned int nr_iovecs)
 418 {
 419         return bio_alloc_bioset(gfp_mask, nr_iovecs, &fs_bio_set);
 420 }
 421
 422 static inline struct bio *bio_kmalloc(gfp_t gfp_mask, unsigned int nr_iovecs)
 423 {
 424         return bio_alloc_bioset(gfp_mask, nr_iovecs, NULL);
 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 struct request_queue;
 445
 446 extern int submit_bio_wait(struct bio *bio);
 447 extern void bio_advance(struct bio *, unsigned);
 448
 449 extern void bio_init(struct bio *bio, struct bio_vec *table,
 450                      unsigned short max_vecs);
 451 extern void bio_uninit(struct bio *);
 452 extern void bio_reset(struct bio *);
 453 void bio_chain(struct bio *, struct bio *);
 454
 455 extern int bio_add_page(struct bio *, struct page *, unsigned int,unsigned int);
 456 extern int bio_add_pc_page(struct request_queue *, struct bio *, struct page *,
 457                            unsigned int, unsigned int);
 458 bool __bio_try_merge_page(struct bio *bio, struct page *page,
 459                 unsigned int len, unsigned int off, bool *same_page);
 460 void __bio_add_page(struct bio *bio, struct page *page,
 461                 unsigned int len, unsigned int off);
 462 int bio_iov_iter_get_pages(struct bio *bio, struct iov_iter *iter);
 463 void bio_release_pages(struct bio *bio, bool mark_dirty);
 464 extern void bio_set_pages_dirty(struct bio *bio);
 465 extern void bio_check_pages_dirty(struct bio *bio);
 466
 467 extern void bio_copy_data_iter(struct bio *dst, struct bvec_iter *dst_iter,
 468                                struct bio *src, struct bvec_iter *src_iter);
 469 extern void bio_copy_data(struct bio *dst, struct bio *src);
 470 extern void bio_list_copy_data(struct bio *dst, struct bio *src);
 471 extern void bio_free_pages(struct bio *bio);
 472 void zero_fill_bio_iter(struct bio *bio, struct bvec_iter iter);
 473 void bio_truncate(struct bio *bio, unsigned new_size);
 474 void guard_bio_eod(struct bio *bio);
 475
 476 static inline void zero_fill_bio(struct bio *bio)
 477 {
 478         zero_fill_bio_iter(bio, bio->bi_iter);
 479 }
 480
 481 extern struct bio_vec *bvec_alloc(gfp_t, int, unsigned long *, mempool_t *);
 482 extern void bvec_free(mempool_t *, struct bio_vec *, unsigned int);
 483 extern unsigned int bvec_nr_vecs(unsigned short idx);
 484 extern const char *bio_devname(struct bio *bio, char *buffer);
 485
 486 #define bio_set_dev(bio, bdev)                  \
 487 do {                                            \
 488         if ((bio)->bi_disk != (bdev)->bd_disk)  \
 489                 bio_clear_flag(bio, BIO_THROTTLED);\
 490         (bio)->bi_disk = (bdev)->bd_disk;       \
 491         (bio)->bi_partno = (bdev)->bd_partno;   \
 492         bio_associate_blkg(bio);                \
 493 } while (0)
 494
 495 #define bio_copy_dev(dst, src)                  \
 496 do {                                            \
 497         (dst)->bi_disk = (src)->bi_disk;        \
 498         (dst)->bi_partno = (src)->bi_partno;    \
 499         bio_clone_blkg_association(dst, src);   \
 500 } while (0)
 501
 502 #define bio_dev(bio) \
 503         disk_devt((bio)->bi_disk)
 504
 505 #ifdef CONFIG_BLK_CGROUP
 506 void bio_associate_blkg(struct bio *bio);
 507 void bio_associate_blkg_from_css(struct bio *bio,
 508                                  struct cgroup_subsys_state *css);
 509 void bio_clone_blkg_association(struct bio *dst, struct bio *src);
 510 #else   /* CONFIG_BLK_CGROUP */
 511 static inline void bio_associate_blkg(struct bio *bio) { }
 512 static inline void bio_associate_blkg_from_css(struct bio *bio,
 513                                                struct cgroup_subsys_state *css)
 514 { }
 515 static inline void bio_clone_blkg_association(struct bio *dst,
 516                                               struct bio *src) { }
 517 #endif  /* CONFIG_BLK_CGROUP */
 518
 519 #ifdef CONFIG_HIGHMEM
 520 /*
 521  * remember never ever reenable interrupts between a bvec_kmap_irq and
 522  * bvec_kunmap_irq!
 523  */
 524 static inline char *bvec_kmap_irq(struct bio_vec *bvec, unsigned long *flags)
 525 {
 526         unsigned long addr;
 527
 528         /*
 529          * might not be a highmem page, but the preempt/irq count
 530          * balancing is a lot nicer this way
 531          */
 532         local_irq_save(*flags);
 533         addr = (unsigned long) kmap_atomic(bvec->bv_page);
 534
 535         BUG_ON(addr & ~PAGE_MASK);
 536
 537         return (char *) addr + bvec->bv_offset;
 538 }
 539
 540 static inline void bvec_kunmap_irq(char *buffer, unsigned long *flags)
 541 {
 542         unsigned long ptr = (unsigned long) buffer & PAGE_MASK;
 543
 544         kunmap_atomic((void *) ptr);
 545         local_irq_restore(*flags);
 546 }
 547
 548 #else
 549 static inline char *bvec_kmap_irq(struct bio_vec *bvec, unsigned long *flags)
 550 {
 551         return page_address(bvec->bv_page) + bvec->bv_offset;
 552 }
 553
 554 static inline void bvec_kunmap_irq(char *buffer, unsigned long *flags)
 555 {
 556         *flags = 0;
 557 }
 558 #endif
 559
 560 /*
 561  * BIO list management for use by remapping drivers (e.g. DM or MD) and loop.
 562  *
 563  * A bio_list anchors a singly-linked list of bios chained through the bi_next
 564  * member of the bio.  The bio_list also caches the last list member to allow
 565  * fast access to the tail.
 566  */
 567 struct bio_list {
 568         struct bio *head;
 569         struct bio *tail;
 570 };
 571
 572 static inline int bio_list_empty(const struct bio_list *bl)
 573 {
 574         return bl->head == NULL;
 575 }
 576
 577 static inline void bio_list_init(struct bio_list *bl)
 578 {
 579         bl->head = bl->tail = NULL;
 580 }
 581
 582 #define BIO_EMPTY_LIST  { NULL, NULL }
 583
 584 #define bio_list_for_each(bio, bl) \
 585         for (bio = (bl)->head; bio; bio = bio->bi_next)
 586
 587 static inline unsigned bio_list_size(const struct bio_list *bl)
 588 {
 589         unsigned sz = 0;
 590         struct bio *bio;
 591
 592         bio_list_for_each(bio, bl)
 593                 sz++;
 594
 595         return sz;
 596 }
 597
 598 static inline void bio_list_add(struct bio_list *bl, struct bio *bio)
 599 {
 600         bio->bi_next = NULL;
 601
 602         if (bl->tail)
 603                 bl->tail->bi_next = bio;
 604         else
 605                 bl->head = bio;
 606
 607         bl->tail = bio;
 608 }
 609
 610 static inline void bio_list_add_head(struct bio_list *bl, struct bio *bio)
 611 {
 612         bio->bi_next = bl->head;
 613
 614         bl->head = bio;
 615
 616         if (!bl->tail)
 617                 bl->tail = bio;
 618 }
 619
 620 static inline void bio_list_merge(struct bio_list *bl, struct bio_list *bl2)
 621 {
 622         if (!bl2->head)
 623                 return;
 624
 625         if (bl->tail)
 626                 bl->tail->bi_next = bl2->head;
 627         else
 628                 bl->head = bl2->head;
 629
 630         bl->tail = bl2->tail;
 631 }
 632
 633 static inline void bio_list_merge_head(struct bio_list *bl,
 634                                        struct bio_list *bl2)
 635 {
 636         if (!bl2->head)
 637                 return;
 638
 639         if (bl->head)
 640                 bl2->tail->bi_next = bl->head;
 641         else
 642                 bl->tail = bl2->tail;
 643
 644         bl->head = bl2->head;
 645 }
 646
 647 static inline struct bio *bio_list_peek(struct bio_list *bl)
 648 {
 649         return bl->head;
 650 }
 651
 652 static inline struct bio *bio_list_pop(struct bio_list *bl)
 653 {
 654         struct bio *bio = bl->head;
 655
 656         if (bio) {
 657                 bl->head = bl->head->bi_next;
 658                 if (!bl->head)
 659                         bl->tail = NULL;
 660
 661                 bio->bi_next = NULL;
 662         }
 663
 664         return bio;
 665 }
 666
 667 static inline struct bio *bio_list_get(struct bio_list *bl)
 668 {
 669         struct bio *bio = bl->head;
 670
 671         bl->head = bl->tail = NULL;
 672
 673         return bio;
 674 }
 675
 676 /*
 677  * Increment chain count for the bio. Make sure the CHAIN flag update
 678  * is visible before the raised count.
 679  */
 680 static inline void bio_inc_remaining(struct bio *bio)
 681 {
 682         bio_set_flag(bio, BIO_CHAIN);
 683         smp_mb__before_atomic();
 684         atomic_inc(&bio->__bi_remaining);
 685 }
 686
 687 /*
 688  * bio_set is used to allow other portions of the IO system to
 689  * allocate their own private memory pools for bio and iovec structures.
 690  * These memory pools in turn all allocate from the bio_slab
 691  * and the bvec_slabs[].
 692  */
 693 #define BIO_POOL_SIZE 2
 694
 695 struct bio_set {
 696         struct kmem_cache *bio_slab;
 697         unsigned int front_pad;
 698
 699         mempool_t bio_pool;
 700         mempool_t bvec_pool;
 701 #if defined(CONFIG_BLK_DEV_INTEGRITY)
 702         mempool_t bio_integrity_pool;
 703         mempool_t bvec_integrity_pool;
 704 #endif
 705
 706         /*
 707          * Deadlock avoidance for stacking block drivers: see comments in
 708          * bio_alloc_bioset() for details
 709          */
 710         spinlock_t              rescue_lock;
 711         struct bio_list         rescue_list;
 712         struct work_struct      rescue_work;
 713         struct workqueue_struct *rescue_workqueue;
 714 };
 715
 716 struct biovec_slab {
 717         int nr_vecs;
 718         char *name;
 719         struct kmem_cache *slab;
 720 };
 721
 722 static inline bool bioset_initialized(struct bio_set *bs)
 723 {
 724         return bs->bio_slab != NULL;
 725 }
 726
 727 #if defined(CONFIG_BLK_DEV_INTEGRITY)
 728
 729 #define bip_for_each_vec(bvl, bip, iter)                                \
 730         for_each_bvec(bvl, (bip)->bip_vec, iter, (bip)->bip_iter)
 731
 732 #define bio_for_each_integrity_vec(_bvl, _bio, _iter)                   \
 733         for_each_bio(_bio)                                              \
 734                 bip_for_each_vec(_bvl, _bio->bi_integrity, _iter)
 735
 736 extern struct bio_integrity_payload *bio_integrity_alloc(struct bio *, gfp_t, unsigned int);
 737 extern int bio_integrity_add_page(struct bio *, struct page *, unsigned int, unsigned int);
 738 extern bool bio_integrity_prep(struct bio *);
 739 extern void bio_integrity_advance(struct bio *, unsigned int);
 740 extern void bio_integrity_trim(struct bio *);
 741 extern int bio_integrity_clone(struct bio *, struct bio *, gfp_t);
 742 extern int bioset_integrity_create(struct bio_set *, int);
 743 extern void bioset_integrity_free(struct bio_set *);
 744 extern void bio_integrity_init(void);
 745
 746 #else /* CONFIG_BLK_DEV_INTEGRITY */
 747
 748 static inline void *bio_integrity(struct bio *bio)
 749 {
 750         return NULL;
 751 }
 752
 753 static inline int bioset_integrity_create(struct bio_set *bs, int pool_size)
 754 {
 755         return 0;
 756 }
 757
 758 static inline void bioset_integrity_free (struct bio_set *bs)
 759 {
 760         return;
 761 }
 762
 763 static inline bool bio_integrity_prep(struct bio *bio)
 764 {
 765         return true;
 766 }
 767
 768 static inline int bio_integrity_clone(struct bio *bio, struct bio *bio_src,
 769                                       gfp_t gfp_mask)
 770 {
 771         return 0;
 772 }
 773
 774 static inline void bio_integrity_advance(struct bio *bio,
 775                                          unsigned int bytes_done)
 776 {
 777         return;
 778 }
 779
 780 static inline void bio_integrity_trim(struct bio *bio)
 781 {
 782         return;
 783 }
 784
 785 static inline void bio_integrity_init(void)
 786 {
 787         return;
 788 }
 789
 790 static inline bool bio_integrity_flagged(struct bio *bio, enum bip_flags flag)
 791 {
 792         return false;
 793 }
 794
 795 static inline void *bio_integrity_alloc(struct bio * bio, gfp_t gfp,
 796                                                                 unsigned int nr)
 797 {
 798         return ERR_PTR(-EINVAL);
 799 }
 800
 801 static inline int bio_integrity_add_page(struct bio *bio, struct page *page,
 802                                         unsigned int len, unsigned int offset)
 803 {
 804         return 0;
 805 }
 806
 807 #endif /* CONFIG_BLK_DEV_INTEGRITY */
 808
 809 /*
 810  * Mark a bio as polled. Note that for async polled IO, the caller must
 811  * expect -EWOULDBLOCK if we cannot allocate a request (or other resources).
 812  * We cannot block waiting for requests on polled IO, as those completions
 813  * must be found by the caller. This is different than IRQ driven IO, where
 814  * it's safe to wait for IO to complete.
 815  */
 816 static inline void bio_set_polled(struct bio *bio, struct kiocb *kiocb)
 817 {
 818         bio->bi_opf |= REQ_HIPRI;
 819         if (!is_sync_kiocb(kiocb))
 820                 bio->bi_opf |= REQ_NOWAIT;
 821 }
 822
 823 #endif /* __LINUX_BIO_H */