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
  12 #ifdef CONFIG_BLOCK
  13 /* struct bio, bio_vec and BIO_* flags are defined in blk_types.h */
  14 #include <linux/blk_types.h>
  15
  16 #define BIO_DEBUG
  17
  18 #ifdef BIO_DEBUG
  19 #define BIO_BUG_ON      BUG_ON
  20 #else
  21 #define BIO_BUG_ON
  22 #endif
  23
  24 #define BIO_MAX_PAGES           256
  25
  26 #define bio_prio(bio)                   (bio)->bi_ioprio
  27 #define bio_set_prio(bio, prio)         ((bio)->bi_ioprio = prio)
  28
  29 #define bio_iter_iovec(bio, iter)                               \
  30         bvec_iter_bvec((bio)->bi_io_vec, (iter))
  31
  32 #define bio_iter_page(bio, iter)                                \
  33         bvec_iter_page((bio)->bi_io_vec, (iter))
  34 #define bio_iter_len(bio, iter)                                 \
  35         bvec_iter_len((bio)->bi_io_vec, (iter))
  36 #define bio_iter_offset(bio, iter)                              \
  37         bvec_iter_offset((bio)->bi_io_vec, (iter))
  38
  39 #define bio_page(bio)           bio_iter_page((bio), (bio)->bi_iter)
  40 #define bio_offset(bio)         bio_iter_offset((bio), (bio)->bi_iter)
  41 #define bio_iovec(bio)          bio_iter_iovec((bio), (bio)->bi_iter)
  42
  43 #define bio_multiple_segments(bio)                              \
  44         ((bio)->bi_iter.bi_size != bio_iovec(bio).bv_len)
  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(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 static inline bool bio_full(struct bio *bio)
 106 {
 107         return bio->bi_vcnt >= bio->bi_max_vecs;
 108 }
 109
 110 static inline bool bio_next_segment(const struct bio *bio,
 111                                     struct bvec_iter_all *iter)
 112 {
 113         if (iter->idx >= bio->bi_vcnt)
 114                 return false;
 115
 116         bvec_advance(&bio->bi_io_vec[iter->idx], iter);
 117         return true;
 118 }
 119
 120 /*
 121  * drivers should _never_ use the all version - the bio may have been split
 122  * before it got to the driver and the driver won't own all of it
 123  */
 124 #define bio_for_each_segment_all(bvl, bio, iter) \
 125         for (bvl = bvec_init_iter_all(&iter); bio_next_segment((bio), &iter); )
 126
 127 static inline void bio_advance_iter(struct bio *bio, struct bvec_iter *iter,
 128                                     unsigned bytes)
 129 {
 130         iter->bi_sector += bytes >> 9;
 131
 132         if (bio_no_advance_iter(bio))
 133                 iter->bi_size -= bytes;
 134         else
 135                 bvec_iter_advance(bio->bi_io_vec, iter, bytes);
 136                 /* TODO: It is reasonable to complete bio with error here. */
 137 }
 138
 139 #define __bio_for_each_segment(bvl, bio, iter, start)                   \
 140         for (iter = (start);                                            \
 141              (iter).bi_size &&                                          \
 142                 ((bvl = bio_iter_iovec((bio), (iter))), 1);             \
 143              bio_advance_iter((bio), &(iter), (bvl).bv_len))
 144
 145 #define bio_for_each_segment(bvl, bio, iter)                            \
 146         __bio_for_each_segment(bvl, bio, iter, (bio)->bi_iter)
 147
 148 #define __bio_for_each_bvec(bvl, bio, iter, start)              \
 149         for (iter = (start);                                            \
 150              (iter).bi_size &&                                          \
 151                 ((bvl = mp_bvec_iter_bvec((bio)->bi_io_vec, (iter))), 1); \
 152              bio_advance_iter((bio), &(iter), (bvl).bv_len))
 153
 154 /* iterate over multi-page bvec */
 155 #define bio_for_each_bvec(bvl, bio, iter)                       \
 156         __bio_for_each_bvec(bvl, bio, iter, (bio)->bi_iter)
 157
 158 #define bio_iter_last(bvec, iter) ((iter).bi_size == (bvec).bv_len)
 159
 160 static inline unsigned bio_segments(struct bio *bio)
 161 {
 162         unsigned segs = 0;
 163         struct bio_vec bv;
 164         struct bvec_iter iter;
 165
 166         /*
 167          * We special case discard/write same/write zeroes, because they
 168          * interpret bi_size differently:
 169          */
 170
 171         switch (bio_op(bio)) {
 172         case REQ_OP_DISCARD:
 173         case REQ_OP_SECURE_ERASE:
 174         case REQ_OP_WRITE_ZEROES:
 175                 return 0;
 176         case REQ_OP_WRITE_SAME:
 177                 return 1;
 178         default:
 179                 break;
 180         }
 181
 182         bio_for_each_segment(bv, bio, iter)
 183                 segs++;
 184
 185         return segs;
 186 }
 187
 188 /*
 189  * get a reference to a bio, so it won't disappear. the intended use is
 190  * something like:
 191  *
 192  * bio_get(bio);
 193  * submit_bio(rw, bio);
 194  * if (bio->bi_flags ...)
 195  *      do_something
 196  * bio_put(bio);
 197  *
 198  * without the bio_get(), it could potentially complete I/O before submit_bio
 199  * returns. and then bio would be freed memory when if (bio->bi_flags ...)
 200  * runs
 201  */
 202 static inline void bio_get(struct bio *bio)
 203 {
 204         bio->bi_flags |= (1 << BIO_REFFED);
 205         smp_mb__before_atomic();
 206         atomic_inc(&bio->__bi_cnt);
 207 }
 208
 209 static inline void bio_cnt_set(struct bio *bio, unsigned int count)
 210 {
 211         if (count != 1) {
 212                 bio->bi_flags |= (1 << BIO_REFFED);
 213                 smp_mb();
 214         }
 215         atomic_set(&bio->__bi_cnt, count);
 216 }
 217
 218 static inline bool bio_flagged(struct bio *bio, unsigned int bit)
 219 {
 220         return (bio->bi_flags & (1U << bit)) != 0;
 221 }
 222
 223 static inline void bio_set_flag(struct bio *bio, unsigned int bit)
 224 {
 225         bio->bi_flags |= (1U << bit);
 226 }
 227
 228 static inline void bio_clear_flag(struct bio *bio, unsigned int bit)
 229 {
 230         bio->bi_flags &= ~(1U << bit);
 231 }
 232
 233 static inline void bio_get_first_bvec(struct bio *bio, struct bio_vec *bv)
 234 {
 235         *bv = bio_iovec(bio);
 236 }
 237
 238 static inline void bio_get_last_bvec(struct bio *bio, struct bio_vec *bv)
 239 {
 240         struct bvec_iter iter = bio->bi_iter;
 241         int idx;
 242
 243         if (unlikely(!bio_multiple_segments(bio))) {
 244                 *bv = bio_iovec(bio);
 245                 return;
 246         }
 247
 248         bio_advance_iter(bio, &iter, iter.bi_size);
 249
 250         if (!iter.bi_bvec_done)
 251                 idx = iter.bi_idx - 1;
 252         else    /* in the middle of bvec */
 253                 idx = iter.bi_idx;
 254
 255         *bv = bio->bi_io_vec[idx];
 256
 257         /*
 258          * iter.bi_bvec_done records actual length of the last bvec
 259          * if this bio ends in the middle of one io vector
 260          */
 261         if (iter.bi_bvec_done)
 262                 bv->bv_len = iter.bi_bvec_done;
 263 }
 264
 265 static inline struct bio_vec *bio_first_bvec_all(struct bio *bio)
 266 {
 267         WARN_ON_ONCE(bio_flagged(bio, BIO_CLONED));
 268         return bio->bi_io_vec;
 269 }
 270
 271 static inline struct page *bio_first_page_all(struct bio *bio)
 272 {
 273         return bio_first_bvec_all(bio)->bv_page;
 274 }
 275
 276 static inline struct bio_vec *bio_last_bvec_all(struct bio *bio)
 277 {
 278         WARN_ON_ONCE(bio_flagged(bio, BIO_CLONED));
 279         return &bio->bi_io_vec[bio->bi_vcnt - 1];
 280 }
 281
 282 enum bip_flags {
 283         BIP_BLOCK_INTEGRITY     = 1 << 0, /* block layer owns integrity data */
 284         BIP_MAPPED_INTEGRITY    = 1 << 1, /* ref tag has been remapped */
 285         BIP_CTRL_NOCHECK        = 1 << 2, /* disable HBA integrity checking */
 286         BIP_DISK_NOCHECK        = 1 << 3, /* disable disk integrity checking */
 287         BIP_IP_CHECKSUM         = 1 << 4, /* IP checksum */
 288 };
 289
 290 /*
 291  * bio integrity payload
 292  */
 293 struct bio_integrity_payload {
 294         struct bio              *bip_bio;       /* parent bio */
 295
 296         struct bvec_iter        bip_iter;
 297
 298         unsigned short          bip_slab;       /* slab the bip came from */
 299         unsigned short          bip_vcnt;       /* # of integrity bio_vecs */
 300         unsigned short          bip_max_vcnt;   /* integrity bio_vec slots */
 301         unsigned short          bip_flags;      /* control flags */
 302
 303         struct bvec_iter        bio_iter;       /* for rewinding parent bio */
 304
 305         struct work_struct      bip_work;       /* I/O completion */
 306
 307         struct bio_vec          *bip_vec;
 308         struct bio_vec          bip_inline_vecs[0];/* embedded bvec array */
 309 };
 310
 311 #if defined(CONFIG_BLK_DEV_INTEGRITY)
 312
 313 static inline struct bio_integrity_payload *bio_integrity(struct bio *bio)
 314 {
 315         if (bio->bi_opf & REQ_INTEGRITY)
 316                 return bio->bi_integrity;
 317
 318         return NULL;
 319 }
 320
 321 static inline bool bio_integrity_flagged(struct bio *bio, enum bip_flags flag)
 322 {
 323         struct bio_integrity_payload *bip = bio_integrity(bio);
 324
 325         if (bip)
 326                 return bip->bip_flags & flag;
 327
 328         return false;
 329 }
 330
 331 static inline sector_t bip_get_seed(struct bio_integrity_payload *bip)
 332 {
 333         return bip->bip_iter.bi_sector;
 334 }
 335
 336 static inline void bip_set_seed(struct bio_integrity_payload *bip,
 337                                 sector_t seed)
 338 {
 339         bip->bip_iter.bi_sector = seed;
 340 }
 341
 342 #endif /* CONFIG_BLK_DEV_INTEGRITY */
 343
 344 extern void bio_trim(struct bio *bio, int offset, int size);
 345 extern struct bio *bio_split(struct bio *bio, int sectors,
 346                              gfp_t gfp, struct bio_set *bs);
 347
 348 /**
 349  * bio_next_split - get next @sectors from a bio, splitting if necessary
 350  * @bio:        bio to split
 351  * @sectors:    number of sectors to split from the front of @bio
 352  * @gfp:        gfp mask
 353  * @bs:         bio set to allocate from
 354  *
 355  * Returns a bio representing the next @sectors of @bio - if the bio is smaller
 356  * than @sectors, returns the original bio unchanged.
 357  */
 358 static inline struct bio *bio_next_split(struct bio *bio, int sectors,
 359                                          gfp_t gfp, struct bio_set *bs)
 360 {
 361         if (sectors >= bio_sectors(bio))
 362                 return bio;
 363
 364         return bio_split(bio, sectors, gfp, bs);
 365 }
 366
 367 enum {
 368         BIOSET_NEED_BVECS = BIT(0),
 369         BIOSET_NEED_RESCUER = BIT(1),
 370 };
 371 extern int bioset_init(struct bio_set *, unsigned int, unsigned int, int flags);
 372 extern void bioset_exit(struct bio_set *);
 373 extern int biovec_init_pool(mempool_t *pool, int pool_entries);
 374 extern int bioset_init_from_src(struct bio_set *bs, struct bio_set *src);
 375
 376 extern struct bio *bio_alloc_bioset(gfp_t, unsigned int, struct bio_set *);
 377 extern void bio_put(struct bio *);
 378
 379 extern void __bio_clone_fast(struct bio *, struct bio *);
 380 extern struct bio *bio_clone_fast(struct bio *, gfp_t, struct bio_set *);
 381
 382 extern struct bio_set fs_bio_set;
 383
 384 static inline struct bio *bio_alloc(gfp_t gfp_mask, unsigned int nr_iovecs)
 385 {
 386         return bio_alloc_bioset(gfp_mask, nr_iovecs, &fs_bio_set);
 387 }
 388
 389 static inline struct bio *bio_kmalloc(gfp_t gfp_mask, unsigned int nr_iovecs)
 390 {
 391         return bio_alloc_bioset(gfp_mask, nr_iovecs, NULL);
 392 }
 393
 394 extern blk_qc_t submit_bio(struct bio *);
 395
 396 extern void bio_endio(struct bio *);
 397
 398 static inline void bio_io_error(struct bio *bio)
 399 {
 400         bio->bi_status = BLK_STS_IOERR;
 401         bio_endio(bio);
 402 }
 403
 404 static inline void bio_wouldblock_error(struct bio *bio)
 405 {
 406         bio->bi_status = BLK_STS_AGAIN;
 407         bio_endio(bio);
 408 }
 409
 410 struct request_queue;
 411 extern int bio_phys_segments(struct request_queue *, struct bio *);
 412
 413 extern int submit_bio_wait(struct bio *bio);
 414 extern void bio_advance(struct bio *, unsigned);
 415
 416 extern void bio_init(struct bio *bio, struct bio_vec *table,
 417                      unsigned short max_vecs);
 418 extern void bio_uninit(struct bio *);
 419 extern void bio_reset(struct bio *);
 420 void bio_chain(struct bio *, struct bio *);
 421
 422 extern int bio_add_page(struct bio *, struct page *, unsigned int,unsigned int);
 423 extern int bio_add_pc_page(struct request_queue *, struct bio *, struct page *,
 424                            unsigned int, unsigned int);
 425 bool __bio_try_merge_page(struct bio *bio, struct page *page,
 426                 unsigned int len, unsigned int off, bool *same_page);
 427 void __bio_add_page(struct bio *bio, struct page *page,
 428                 unsigned int len, unsigned int off);
 429 int bio_iov_iter_get_pages(struct bio *bio, struct iov_iter *iter);
 430 struct rq_map_data;
 431 extern struct bio *bio_map_user_iov(struct request_queue *,
 432                                     struct iov_iter *, gfp_t);
 433 extern void bio_unmap_user(struct bio *);
 434 extern struct bio *bio_map_kern(struct request_queue *, void *, unsigned int,
 435                                 gfp_t);
 436 extern struct bio *bio_copy_kern(struct request_queue *, void *, unsigned int,
 437                                  gfp_t, int);
 438 extern void bio_set_pages_dirty(struct bio *bio);
 439 extern void bio_check_pages_dirty(struct bio *bio);
 440
 441 void generic_start_io_acct(struct request_queue *q, int op,
 442                                 unsigned long sectors, struct hd_struct *part);
 443 void generic_end_io_acct(struct request_queue *q, int op,
 444                                 struct hd_struct *part,
 445                                 unsigned long start_time);
 446
 447 #ifndef ARCH_IMPLEMENTS_FLUSH_DCACHE_PAGE
 448 # error "You should define ARCH_IMPLEMENTS_FLUSH_DCACHE_PAGE for your platform"
 449 #endif
 450 #if ARCH_IMPLEMENTS_FLUSH_DCACHE_PAGE
 451 extern void bio_flush_dcache_pages(struct bio *bi);
 452 #else
 453 static inline void bio_flush_dcache_pages(struct bio *bi)
 454 {
 455 }
 456 #endif
 457
 458 extern void bio_copy_data_iter(struct bio *dst, struct bvec_iter *dst_iter,
 459                                struct bio *src, struct bvec_iter *src_iter);
 460 extern void bio_copy_data(struct bio *dst, struct bio *src);
 461 extern void bio_list_copy_data(struct bio *dst, struct bio *src);
 462 extern void bio_free_pages(struct bio *bio);
 463
 464 extern struct bio *bio_copy_user_iov(struct request_queue *,
 465                                      struct rq_map_data *,
 466                                      struct iov_iter *,
 467                                      gfp_t);
 468 extern int bio_uncopy_user(struct bio *);
 469 void zero_fill_bio_iter(struct bio *bio, struct bvec_iter iter);
 470
 471 static inline void zero_fill_bio(struct bio *bio)
 472 {
 473         zero_fill_bio_iter(bio, bio->bi_iter);
 474 }
 475
 476 extern struct bio_vec *bvec_alloc(gfp_t, int, unsigned long *, mempool_t *);
 477 extern void bvec_free(mempool_t *, struct bio_vec *, unsigned int);
 478 extern unsigned int bvec_nr_vecs(unsigned short idx);
 479 extern const char *bio_devname(struct bio *bio, char *buffer);
 480
 481 #define bio_set_dev(bio, bdev)                  \
 482 do {                                            \
 483         if ((bio)->bi_disk != (bdev)->bd_disk)  \
 484                 bio_clear_flag(bio, BIO_THROTTLED);\
 485         (bio)->bi_disk = (bdev)->bd_disk;       \
 486         (bio)->bi_partno = (bdev)->bd_partno;   \
 487         bio_associate_blkg(bio);                \
 488 } while (0)
 489
 490 #define bio_copy_dev(dst, src)                  \
 491 do {                                            \
 492         (dst)->bi_disk = (src)->bi_disk;        \
 493         (dst)->bi_partno = (src)->bi_partno;    \
 494         bio_clone_blkg_association(dst, src);   \
 495 } while (0)
 496
 497 #define bio_dev(bio) \
 498         disk_devt((bio)->bi_disk)
 499
 500 #if defined(CONFIG_MEMCG) && defined(CONFIG_BLK_CGROUP)
 501 void bio_associate_blkg_from_page(struct bio *bio, struct page *page);
 502 #else
 503 static inline void bio_associate_blkg_from_page(struct bio *bio,
 504                                                 struct page *page) { }
 505 #endif
 506
 507 #ifdef CONFIG_BLK_CGROUP
 508 void bio_disassociate_blkg(struct bio *bio);
 509 void bio_associate_blkg(struct bio *bio);
 510 void bio_associate_blkg_from_css(struct bio *bio,
 511                                  struct cgroup_subsys_state *css);
 512 void bio_clone_blkg_association(struct bio *dst, struct bio *src);
 513 #else   /* CONFIG_BLK_CGROUP */
 514 static inline void bio_disassociate_blkg(struct bio *bio) { }
 515 static inline void bio_associate_blkg(struct bio *bio) { }
 516 static inline void bio_associate_blkg_from_css(struct bio *bio,
 517                                                struct cgroup_subsys_state *css)
 518 { }
 519 static inline void bio_clone_blkg_association(struct bio *dst,
 520                                               struct bio *src) { }
 521 #endif  /* CONFIG_BLK_CGROUP */
 522
 523 #ifdef CONFIG_HIGHMEM
 524 /*
 525  * remember never ever reenable interrupts between a bvec_kmap_irq and
 526  * bvec_kunmap_irq!
 527  */
 528 static inline char *bvec_kmap_irq(struct bio_vec *bvec, unsigned long *flags)
 529 {
 530         unsigned long addr;
 531
 532         /*
 533          * might not be a highmem page, but the preempt/irq count
 534          * balancing is a lot nicer this way
 535          */
 536         local_irq_save(*flags);
 537         addr = (unsigned long) kmap_atomic(bvec->bv_page);
 538
 539         BUG_ON(addr & ~PAGE_MASK);
 540
 541         return (char *) addr + bvec->bv_offset;
 542 }
 543
 544 static inline void bvec_kunmap_irq(char *buffer, unsigned long *flags)
 545 {
 546         unsigned long ptr = (unsigned long) buffer & PAGE_MASK;
 547
 548         kunmap_atomic((void *) ptr);
 549         local_irq_restore(*flags);
 550 }
 551
 552 #else
 553 static inline char *bvec_kmap_irq(struct bio_vec *bvec, unsigned long *flags)
 554 {
 555         return page_address(bvec->bv_page) + bvec->bv_offset;
 556 }
 557
 558 static inline void bvec_kunmap_irq(char *buffer, unsigned long *flags)
 559 {
 560         *flags = 0;
 561 }
 562 #endif
 563
 564 /*
 565  * BIO list management for use by remapping drivers (e.g. DM or MD) and loop.
 566  *
 567  * A bio_list anchors a singly-linked list of bios chained through the bi_next
 568  * member of the bio.  The bio_list also caches the last list member to allow
 569  * fast access to the tail.
 570  */
 571 struct bio_list {
 572         struct bio *head;
 573         struct bio *tail;
 574 };
 575
 576 static inline int bio_list_empty(const struct bio_list *bl)
 577 {
 578         return bl->head == NULL;
 579 }
 580
 581 static inline void bio_list_init(struct bio_list *bl)
 582 {
 583         bl->head = bl->tail = NULL;
 584 }
 585
 586 #define BIO_EMPTY_LIST  { NULL, NULL }
 587
 588 #define bio_list_for_each(bio, bl) \
 589         for (bio = (bl)->head; bio; bio = bio->bi_next)
 590
 591 static inline unsigned bio_list_size(const struct bio_list *bl)
 592 {
 593         unsigned sz = 0;
 594         struct bio *bio;
 595
 596         bio_list_for_each(bio, bl)
 597                 sz++;
 598
 599         return sz;
 600 }
 601
 602 static inline void bio_list_add(struct bio_list *bl, struct bio *bio)
 603 {
 604         bio->bi_next = NULL;
 605
 606         if (bl->tail)
 607                 bl->tail->bi_next = bio;
 608         else
 609                 bl->head = bio;
 610
 611         bl->tail = bio;
 612 }
 613
 614 static inline void bio_list_add_head(struct bio_list *bl, struct bio *bio)
 615 {
 616         bio->bi_next = bl->head;
 617
 618         bl->head = bio;
 619
 620         if (!bl->tail)
 621                 bl->tail = bio;
 622 }
 623
 624 static inline void bio_list_merge(struct bio_list *bl, struct bio_list *bl2)
 625 {
 626         if (!bl2->head)
 627                 return;
 628
 629         if (bl->tail)
 630                 bl->tail->bi_next = bl2->head;
 631         else
 632                 bl->head = bl2->head;
 633
 634         bl->tail = bl2->tail;
 635 }
 636
 637 static inline void bio_list_merge_head(struct bio_list *bl,
 638                                        struct bio_list *bl2)
 639 {
 640         if (!bl2->head)
 641                 return;
 642
 643         if (bl->head)
 644                 bl2->tail->bi_next = bl->head;
 645         else
 646                 bl->tail = bl2->tail;
 647
 648         bl->head = bl2->head;
 649 }
 650
 651 static inline struct bio *bio_list_peek(struct bio_list *bl)
 652 {
 653         return bl->head;
 654 }
 655
 656 static inline struct bio *bio_list_pop(struct bio_list *bl)
 657 {
 658         struct bio *bio = bl->head;
 659
 660         if (bio) {
 661                 bl->head = bl->head->bi_next;
 662                 if (!bl->head)
 663                         bl->tail = NULL;
 664
 665                 bio->bi_next = NULL;
 666         }
 667
 668         return bio;
 669 }
 670
 671 static inline struct bio *bio_list_get(struct bio_list *bl)
 672 {
 673         struct bio *bio = bl->head;
 674
 675         bl->head = bl->tail = NULL;
 676
 677         return bio;
 678 }
 679
 680 /*
 681  * Increment chain count for the bio. Make sure the CHAIN flag update
 682  * is visible before the raised count.
 683  */
 684 static inline void bio_inc_remaining(struct bio *bio)
 685 {
 686         bio_set_flag(bio, BIO_CHAIN);
 687         smp_mb__before_atomic();
 688         atomic_inc(&bio->__bi_remaining);
 689 }
 690
 691 /*
 692  * bio_set is used to allow other portions of the IO system to
 693  * allocate their own private memory pools for bio and iovec structures.
 694  * These memory pools in turn all allocate from the bio_slab
 695  * and the bvec_slabs[].
 696  */
 697 #define BIO_POOL_SIZE 2
 698
 699 struct bio_set {
 700         struct kmem_cache *bio_slab;
 701         unsigned int front_pad;
 702
 703         mempool_t bio_pool;
 704         mempool_t bvec_pool;
 705 #if defined(CONFIG_BLK_DEV_INTEGRITY)
 706         mempool_t bio_integrity_pool;
 707         mempool_t bvec_integrity_pool;
 708 #endif
 709
 710         /*
 711          * Deadlock avoidance for stacking block drivers: see comments in
 712          * bio_alloc_bioset() for details
 713          */
 714         spinlock_t              rescue_lock;
 715         struct bio_list         rescue_list;
 716         struct work_struct      rescue_work;
 717         struct workqueue_struct *rescue_workqueue;
 718 };
 719
 720 struct biovec_slab {
 721         int nr_vecs;
 722         char *name;
 723         struct kmem_cache *slab;
 724 };
 725
 726 static inline bool bioset_initialized(struct bio_set *bs)
 727 {
 728         return bs->bio_slab != NULL;
 729 }
 730
 731 /*
 732  * a small number of entries is fine, not going to be performance critical.
 733  * basically we just need to survive
 734  */
 735 #define BIO_SPLIT_ENTRIES 2
 736
 737 #if defined(CONFIG_BLK_DEV_INTEGRITY)
 738
 739 #define bip_for_each_vec(bvl, bip, iter)                                \
 740         for_each_bvec(bvl, (bip)->bip_vec, iter, (bip)->bip_iter)
 741
 742 #define bio_for_each_integrity_vec(_bvl, _bio, _iter)                   \
 743         for_each_bio(_bio)                                              \
 744                 bip_for_each_vec(_bvl, _bio->bi_integrity, _iter)
 745
 746 extern struct bio_integrity_payload *bio_integrity_alloc(struct bio *, gfp_t, unsigned int);
 747 extern int bio_integrity_add_page(struct bio *, struct page *, unsigned int, unsigned int);
 748 extern bool bio_integrity_prep(struct bio *);
 749 extern void bio_integrity_advance(struct bio *, unsigned int);
 750 extern void bio_integrity_trim(struct bio *);
 751 extern int bio_integrity_clone(struct bio *, struct bio *, gfp_t);
 752 extern int bioset_integrity_create(struct bio_set *, int);
 753 extern void bioset_integrity_free(struct bio_set *);
 754 extern void bio_integrity_init(void);
 755
 756 #else /* CONFIG_BLK_DEV_INTEGRITY */
 757
 758 static inline void *bio_integrity(struct bio *bio)
 759 {
 760         return NULL;
 761 }
 762
 763 static inline int bioset_integrity_create(struct bio_set *bs, int pool_size)
 764 {
 765         return 0;
 766 }
 767
 768 static inline void bioset_integrity_free (struct bio_set *bs)
 769 {
 770         return;
 771 }
 772
 773 static inline bool bio_integrity_prep(struct bio *bio)
 774 {
 775         return true;
 776 }
 777
 778 static inline int bio_integrity_clone(struct bio *bio, struct bio *bio_src,
 779                                       gfp_t gfp_mask)
 780 {
 781         return 0;
 782 }
 783
 784 static inline void bio_integrity_advance(struct bio *bio,
 785                                          unsigned int bytes_done)
 786 {
 787         return;
 788 }
 789
 790 static inline void bio_integrity_trim(struct bio *bio)
 791 {
 792         return;
 793 }
 794
 795 static inline void bio_integrity_init(void)
 796 {
 797         return;
 798 }
 799
 800 static inline bool bio_integrity_flagged(struct bio *bio, enum bip_flags flag)
 801 {
 802         return false;
 803 }
 804
 805 static inline void *bio_integrity_alloc(struct bio * bio, gfp_t gfp,
 806                                                                 unsigned int nr)
 807 {
 808         return ERR_PTR(-EINVAL);
 809 }
 810
 811 static inline int bio_integrity_add_page(struct bio *bio, struct page *page,
 812                                         unsigned int len, unsigned int offset)
 813 {
 814         return 0;
 815 }
 816
 817 #endif /* CONFIG_BLK_DEV_INTEGRITY */
 818
 819 /*
 820  * Mark a bio as polled. Note that for async polled IO, the caller must
 821  * expect -EWOULDBLOCK if we cannot allocate a request (or other resources).
 822  * We cannot block waiting for requests on polled IO, as those completions
 823  * must be found by the caller. This is different than IRQ driven IO, where
 824  * it's safe to wait for IO to complete.
 825  */
 826 static inline void bio_set_polled(struct bio *bio, struct kiocb *kiocb)
 827 {
 828         bio->bi_opf |= REQ_HIPRI;
 829         if (!is_sync_kiocb(kiocb))
 830                 bio->bi_opf |= REQ_NOWAIT;
 831 }
 832
 833 #endif /* CONFIG_BLOCK */
 834 #endif /* __LINUX_BIO_H */