root/include/linux/bio.h

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INCLUDED FROM

DEFINITIONS

This source file includes following definitions.
  1. bio_has_data
  2. bio_no_advance_iter
  3. bio_mergeable
  4. bio_cur_bytes
  5. bio_data
  6. bio_full
  7. bio_next_segment
  8. bio_advance_iter
  9. bio_segments
  10. bio_get
  11. bio_cnt_set
  12. bio_flagged
  13. bio_set_flag
  14. bio_clear_flag
  15. bio_get_first_bvec
  16. bio_get_last_bvec
  17. bio_first_bvec_all
  18. bio_first_page_all
  19. bio_last_bvec_all
  20. bio_integrity_flagged
  21. bip_get_seed
  22. bip_set_seed
  23. bio_next_split
  24. bio_alloc
  25. bio_kmalloc
  26. bio_io_error
  27. bio_wouldblock_error
  28. zero_fill_bio
  29. bio_associate_blkg_from_page
  30. bio_disassociate_blkg
  31. bio_associate_blkg
  32. bio_associate_blkg_from_css
  33. bio_clone_blkg_association
  34. bvec_kmap_irq
  35. bvec_kunmap_irq
  36. bvec_kmap_irq
  37. bvec_kunmap_irq
  38. bio_list_empty
  39. bio_list_init
  40. bio_list_size
  41. bio_list_add
  42. bio_list_add_head
  43. bio_list_merge
  44. bio_list_merge_head
  45. bio_list_peek
  46. bio_list_pop
  47. bio_list_get
  48. bio_inc_remaining
  49. bioset_initialized
  50. bio_integrity
  51. bioset_integrity_create
  52. bioset_integrity_free
  53. bio_integrity_prep
  54. bio_integrity_clone
  55. bio_integrity_advance
  56. bio_integrity_trim
  57. bio_integrity_init
  58. bio_integrity_flagged
  59. bio_integrity_alloc
  60. bio_integrity_add_page
  61. bio_set_polled
   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 /**
 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(struct bio *bio, struct bvec_iter *iter,
 142                                     unsigned 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 #define __bio_for_each_segment(bvl, bio, iter, start)                   \
 154         for (iter = (start);                                            \
 155              (iter).bi_size &&                                          \
 156                 ((bvl = bio_iter_iovec((bio), (iter))), 1);             \
 157              bio_advance_iter((bio), &(iter), (bvl).bv_len))
 158 
 159 #define bio_for_each_segment(bvl, bio, iter)                            \
 160         __bio_for_each_segment(bvl, bio, iter, (bio)->bi_iter)
 161 
 162 #define __bio_for_each_bvec(bvl, bio, iter, start)              \
 163         for (iter = (start);                                            \
 164              (iter).bi_size &&                                          \
 165                 ((bvl = mp_bvec_iter_bvec((bio)->bi_io_vec, (iter))), 1); \
 166              bio_advance_iter((bio), &(iter), (bvl).bv_len))
 167 
 168 /* iterate over multi-page bvec */
 169 #define bio_for_each_bvec(bvl, bio, iter)                       \
 170         __bio_for_each_bvec(bvl, bio, iter, (bio)->bi_iter)
 171 
 172 #define bio_iter_last(bvec, iter) ((iter).bi_size == (bvec).bv_len)
 173 
 174 static inline unsigned bio_segments(struct bio *bio)
 175 {
 176         unsigned segs = 0;
 177         struct bio_vec bv;
 178         struct bvec_iter iter;
 179 
 180         /*
 181          * We special case discard/write same/write zeroes, because they
 182          * interpret bi_size differently:
 183          */
 184 
 185         switch (bio_op(bio)) {
 186         case REQ_OP_DISCARD:
 187         case REQ_OP_SECURE_ERASE:
 188         case REQ_OP_WRITE_ZEROES:
 189                 return 0;
 190         case REQ_OP_WRITE_SAME:
 191                 return 1;
 192         default:
 193                 break;
 194         }
 195 
 196         bio_for_each_segment(bv, bio, iter)
 197                 segs++;
 198 
 199         return segs;
 200 }
 201 
 202 /*
 203  * get a reference to a bio, so it won't disappear. the intended use is
 204  * something like:
 205  *
 206  * bio_get(bio);
 207  * submit_bio(rw, bio);
 208  * if (bio->bi_flags ...)
 209  *      do_something
 210  * bio_put(bio);
 211  *
 212  * without the bio_get(), it could potentially complete I/O before submit_bio
 213  * returns. and then bio would be freed memory when if (bio->bi_flags ...)
 214  * runs
 215  */
 216 static inline void bio_get(struct bio *bio)
 217 {
 218         bio->bi_flags |= (1 << BIO_REFFED);
 219         smp_mb__before_atomic();
 220         atomic_inc(&bio->__bi_cnt);
 221 }
 222 
 223 static inline void bio_cnt_set(struct bio *bio, unsigned int count)
 224 {
 225         if (count != 1) {
 226                 bio->bi_flags |= (1 << BIO_REFFED);
 227                 smp_mb();
 228         }
 229         atomic_set(&bio->__bi_cnt, count);
 230 }
 231 
 232 static inline bool bio_flagged(struct bio *bio, unsigned int bit)
 233 {
 234         return (bio->bi_flags & (1U << bit)) != 0;
 235 }
 236 
 237 static inline void bio_set_flag(struct bio *bio, unsigned int bit)
 238 {
 239         bio->bi_flags |= (1U << bit);
 240 }
 241 
 242 static inline void bio_clear_flag(struct bio *bio, unsigned int bit)
 243 {
 244         bio->bi_flags &= ~(1U << bit);
 245 }
 246 
 247 static inline void bio_get_first_bvec(struct bio *bio, struct bio_vec *bv)
 248 {
 249         *bv = bio_iovec(bio);
 250 }
 251 
 252 static inline void bio_get_last_bvec(struct bio *bio, struct bio_vec *bv)
 253 {
 254         struct bvec_iter iter = bio->bi_iter;
 255         int idx;
 256 
 257         if (unlikely(!bio_multiple_segments(bio))) {
 258                 *bv = bio_iovec(bio);
 259                 return;
 260         }
 261 
 262         bio_advance_iter(bio, &iter, iter.bi_size);
 263 
 264         if (!iter.bi_bvec_done)
 265                 idx = iter.bi_idx - 1;
 266         else    /* in the middle of bvec */
 267                 idx = iter.bi_idx;
 268 
 269         *bv = bio->bi_io_vec[idx];
 270 
 271         /*
 272          * iter.bi_bvec_done records actual length of the last bvec
 273          * if this bio ends in the middle of one io vector
 274          */
 275         if (iter.bi_bvec_done)
 276                 bv->bv_len = iter.bi_bvec_done;
 277 }
 278 
 279 static inline struct bio_vec *bio_first_bvec_all(struct bio *bio)
 280 {
 281         WARN_ON_ONCE(bio_flagged(bio, BIO_CLONED));
 282         return bio->bi_io_vec;
 283 }
 284 
 285 static inline struct page *bio_first_page_all(struct bio *bio)
 286 {
 287         return bio_first_bvec_all(bio)->bv_page;
 288 }
 289 
 290 static inline struct bio_vec *bio_last_bvec_all(struct bio *bio)
 291 {
 292         WARN_ON_ONCE(bio_flagged(bio, BIO_CLONED));
 293         return &bio->bi_io_vec[bio->bi_vcnt - 1];
 294 }
 295 
 296 enum bip_flags {
 297         BIP_BLOCK_INTEGRITY     = 1 << 0, /* block layer owns integrity data */
 298         BIP_MAPPED_INTEGRITY    = 1 << 1, /* ref tag has been remapped */
 299         BIP_CTRL_NOCHECK        = 1 << 2, /* disable HBA integrity checking */
 300         BIP_DISK_NOCHECK        = 1 << 3, /* disable disk integrity checking */
 301         BIP_IP_CHECKSUM         = 1 << 4, /* IP checksum */
 302 };
 303 
 304 /*
 305  * bio integrity payload
 306  */
 307 struct bio_integrity_payload {
 308         struct bio              *bip_bio;       /* parent bio */
 309 
 310         struct bvec_iter        bip_iter;
 311 
 312         unsigned short          bip_slab;       /* slab the bip came from */
 313         unsigned short          bip_vcnt;       /* # of integrity bio_vecs */
 314         unsigned short          bip_max_vcnt;   /* integrity bio_vec slots */
 315         unsigned short          bip_flags;      /* control flags */
 316 
 317         struct bvec_iter        bio_iter;       /* for rewinding parent bio */
 318 
 319         struct work_struct      bip_work;       /* I/O completion */
 320 
 321         struct bio_vec          *bip_vec;
 322         struct bio_vec          bip_inline_vecs[0];/* embedded bvec array */
 323 };
 324 
 325 #if defined(CONFIG_BLK_DEV_INTEGRITY)
 326 
 327 static inline struct bio_integrity_payload *bio_integrity(struct bio *bio)
 328 {
 329         if (bio->bi_opf & REQ_INTEGRITY)
 330                 return bio->bi_integrity;
 331 
 332         return NULL;
 333 }
 334 
 335 static inline bool bio_integrity_flagged(struct bio *bio, enum bip_flags flag)
 336 {
 337         struct bio_integrity_payload *bip = bio_integrity(bio);
 338 
 339         if (bip)
 340                 return bip->bip_flags & flag;
 341 
 342         return false;
 343 }
 344 
 345 static inline sector_t bip_get_seed(struct bio_integrity_payload *bip)
 346 {
 347         return bip->bip_iter.bi_sector;
 348 }
 349 
 350 static inline void bip_set_seed(struct bio_integrity_payload *bip,
 351                                 sector_t seed)
 352 {
 353         bip->bip_iter.bi_sector = seed;
 354 }
 355 
 356 #endif /* CONFIG_BLK_DEV_INTEGRITY */
 357 
 358 extern void bio_trim(struct bio *bio, int offset, int size);
 359 extern struct bio *bio_split(struct bio *bio, int sectors,
 360                              gfp_t gfp, struct bio_set *bs);
 361 
 362 /**
 363  * bio_next_split - get next @sectors from a bio, splitting if necessary
 364  * @bio:        bio to split
 365  * @sectors:    number of sectors to split from the front of @bio
 366  * @gfp:        gfp mask
 367  * @bs:         bio set to allocate from
 368  *
 369  * Returns a bio representing the next @sectors of @bio - if the bio is smaller
 370  * than @sectors, returns the original bio unchanged.
 371  */
 372 static inline struct bio *bio_next_split(struct bio *bio, int sectors,
 373                                          gfp_t gfp, struct bio_set *bs)
 374 {
 375         if (sectors >= bio_sectors(bio))
 376                 return bio;
 377 
 378         return bio_split(bio, sectors, gfp, bs);
 379 }
 380 
 381 enum {
 382         BIOSET_NEED_BVECS = BIT(0),
 383         BIOSET_NEED_RESCUER = BIT(1),
 384 };
 385 extern int bioset_init(struct bio_set *, unsigned int, unsigned int, int flags);
 386 extern void bioset_exit(struct bio_set *);
 387 extern int biovec_init_pool(mempool_t *pool, int pool_entries);
 388 extern int bioset_init_from_src(struct bio_set *bs, struct bio_set *src);
 389 
 390 extern struct bio *bio_alloc_bioset(gfp_t, unsigned int, struct bio_set *);
 391 extern void bio_put(struct bio *);
 392 
 393 extern void __bio_clone_fast(struct bio *, struct bio *);
 394 extern struct bio *bio_clone_fast(struct bio *, gfp_t, struct bio_set *);
 395 
 396 extern struct bio_set fs_bio_set;
 397 
 398 static inline struct bio *bio_alloc(gfp_t gfp_mask, unsigned int nr_iovecs)
 399 {
 400         return bio_alloc_bioset(gfp_mask, nr_iovecs, &fs_bio_set);
 401 }
 402 
 403 static inline struct bio *bio_kmalloc(gfp_t gfp_mask, unsigned int nr_iovecs)
 404 {
 405         return bio_alloc_bioset(gfp_mask, nr_iovecs, NULL);
 406 }
 407 
 408 extern blk_qc_t submit_bio(struct bio *);
 409 
 410 extern void bio_endio(struct bio *);
 411 
 412 static inline void bio_io_error(struct bio *bio)
 413 {
 414         bio->bi_status = BLK_STS_IOERR;
 415         bio_endio(bio);
 416 }
 417 
 418 static inline void bio_wouldblock_error(struct bio *bio)
 419 {
 420         bio->bi_status = BLK_STS_AGAIN;
 421         bio_endio(bio);
 422 }
 423 
 424 struct request_queue;
 425 
 426 extern int submit_bio_wait(struct bio *bio);
 427 extern void bio_advance(struct bio *, unsigned);
 428 
 429 extern void bio_init(struct bio *bio, struct bio_vec *table,
 430                      unsigned short max_vecs);
 431 extern void bio_uninit(struct bio *);
 432 extern void bio_reset(struct bio *);
 433 void bio_chain(struct bio *, struct bio *);
 434 
 435 extern int bio_add_page(struct bio *, struct page *, unsigned int,unsigned int);
 436 extern int bio_add_pc_page(struct request_queue *, struct bio *, struct page *,
 437                            unsigned int, unsigned int);
 438 bool __bio_try_merge_page(struct bio *bio, struct page *page,
 439                 unsigned int len, unsigned int off, bool *same_page);
 440 void __bio_add_page(struct bio *bio, struct page *page,
 441                 unsigned int len, unsigned int off);
 442 int bio_iov_iter_get_pages(struct bio *bio, struct iov_iter *iter);
 443 void bio_release_pages(struct bio *bio, bool mark_dirty);
 444 struct rq_map_data;
 445 extern struct bio *bio_map_user_iov(struct request_queue *,
 446                                     struct iov_iter *, gfp_t);
 447 extern void bio_unmap_user(struct bio *);
 448 extern struct bio *bio_map_kern(struct request_queue *, void *, unsigned int,
 449                                 gfp_t);
 450 extern struct bio *bio_copy_kern(struct request_queue *, void *, unsigned int,
 451                                  gfp_t, int);
 452 extern void bio_set_pages_dirty(struct bio *bio);
 453 extern void bio_check_pages_dirty(struct bio *bio);
 454 
 455 void generic_start_io_acct(struct request_queue *q, int op,
 456                                 unsigned long sectors, struct hd_struct *part);
 457 void generic_end_io_acct(struct request_queue *q, int op,
 458                                 struct hd_struct *part,
 459                                 unsigned long start_time);
 460 
 461 extern void bio_copy_data_iter(struct bio *dst, struct bvec_iter *dst_iter,
 462                                struct bio *src, struct bvec_iter *src_iter);
 463 extern void bio_copy_data(struct bio *dst, struct bio *src);
 464 extern void bio_list_copy_data(struct bio *dst, struct bio *src);
 465 extern void bio_free_pages(struct bio *bio);
 466 
 467 extern struct bio *bio_copy_user_iov(struct request_queue *,
 468                                      struct rq_map_data *,
 469                                      struct iov_iter *,
 470                                      gfp_t);
 471 extern int bio_uncopy_user(struct 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 
 475 static inline void zero_fill_bio(struct bio *bio)
 476 {
 477         zero_fill_bio_iter(bio, bio->bi_iter);
 478 }
 479 
 480 extern struct bio_vec *bvec_alloc(gfp_t, int, unsigned long *, mempool_t *);
 481 extern void bvec_free(mempool_t *, struct bio_vec *, unsigned int);
 482 extern unsigned int bvec_nr_vecs(unsigned short idx);
 483 extern const char *bio_devname(struct bio *bio, char *buffer);
 484 
 485 #define bio_set_dev(bio, bdev)                  \
 486 do {                                            \
 487         if ((bio)->bi_disk != (bdev)->bd_disk)  \
 488                 bio_clear_flag(bio, BIO_THROTTLED);\
 489         (bio)->bi_disk = (bdev)->bd_disk;       \
 490         (bio)->bi_partno = (bdev)->bd_partno;   \
 491         bio_associate_blkg(bio);                \
 492 } while (0)
 493 
 494 #define bio_copy_dev(dst, src)                  \
 495 do {                                            \
 496         (dst)->bi_disk = (src)->bi_disk;        \
 497         (dst)->bi_partno = (src)->bi_partno;    \
 498         bio_clone_blkg_association(dst, src);   \
 499 } while (0)
 500 
 501 #define bio_dev(bio) \
 502         disk_devt((bio)->bi_disk)
 503 
 504 #if defined(CONFIG_MEMCG) && defined(CONFIG_BLK_CGROUP)
 505 void bio_associate_blkg_from_page(struct bio *bio, struct page *page);
 506 #else
 507 static inline void bio_associate_blkg_from_page(struct bio *bio,
 508                                                 struct page *page) { }
 509 #endif
 510 
 511 #ifdef CONFIG_BLK_CGROUP
 512 void bio_disassociate_blkg(struct bio *bio);
 513 void bio_associate_blkg(struct bio *bio);
 514 void bio_associate_blkg_from_css(struct bio *bio,
 515                                  struct cgroup_subsys_state *css);
 516 void bio_clone_blkg_association(struct bio *dst, struct bio *src);
 517 #else   /* CONFIG_BLK_CGROUP */
 518 static inline void bio_disassociate_blkg(struct bio *bio) { }
 519 static inline void bio_associate_blkg(struct bio *bio) { }
 520 static inline void bio_associate_blkg_from_css(struct bio *bio,
 521                                                struct cgroup_subsys_state *css)
 522 { }
 523 static inline void bio_clone_blkg_association(struct bio *dst,
 524                                               struct bio *src) { }
 525 #endif  /* CONFIG_BLK_CGROUP */
 526 
 527 #ifdef CONFIG_HIGHMEM
 528 /*
 529  * remember never ever reenable interrupts between a bvec_kmap_irq and
 530  * bvec_kunmap_irq!
 531  */
 532 static inline char *bvec_kmap_irq(struct bio_vec *bvec, unsigned long *flags)
 533 {
 534         unsigned long addr;
 535 
 536         /*
 537          * might not be a highmem page, but the preempt/irq count
 538          * balancing is a lot nicer this way
 539          */
 540         local_irq_save(*flags);
 541         addr = (unsigned long) kmap_atomic(bvec->bv_page);
 542 
 543         BUG_ON(addr & ~PAGE_MASK);
 544 
 545         return (char *) addr + bvec->bv_offset;
 546 }
 547 
 548 static inline void bvec_kunmap_irq(char *buffer, unsigned long *flags)
 549 {
 550         unsigned long ptr = (unsigned long) buffer & PAGE_MASK;
 551 
 552         kunmap_atomic((void *) ptr);
 553         local_irq_restore(*flags);
 554 }
 555 
 556 #else
 557 static inline char *bvec_kmap_irq(struct bio_vec *bvec, unsigned long *flags)
 558 {
 559         return page_address(bvec->bv_page) + bvec->bv_offset;
 560 }
 561 
 562 static inline void bvec_kunmap_irq(char *buffer, unsigned long *flags)
 563 {
 564         *flags = 0;
 565 }
 566 #endif
 567 
 568 /*
 569  * BIO list management for use by remapping drivers (e.g. DM or MD) and loop.
 570  *
 571  * A bio_list anchors a singly-linked list of bios chained through the bi_next
 572  * member of the bio.  The bio_list also caches the last list member to allow
 573  * fast access to the tail.
 574  */
 575 struct bio_list {
 576         struct bio *head;
 577         struct bio *tail;
 578 };
 579 
 580 static inline int bio_list_empty(const struct bio_list *bl)
 581 {
 582         return bl->head == NULL;
 583 }
 584 
 585 static inline void bio_list_init(struct bio_list *bl)
 586 {
 587         bl->head = bl->tail = NULL;
 588 }
 589 
 590 #define BIO_EMPTY_LIST  { NULL, NULL }
 591 
 592 #define bio_list_for_each(bio, bl) \
 593         for (bio = (bl)->head; bio; bio = bio->bi_next)
 594 
 595 static inline unsigned bio_list_size(const struct bio_list *bl)
 596 {
 597         unsigned sz = 0;
 598         struct bio *bio;
 599 
 600         bio_list_for_each(bio, bl)
 601                 sz++;
 602 
 603         return sz;
 604 }
 605 
 606 static inline void bio_list_add(struct bio_list *bl, struct bio *bio)
 607 {
 608         bio->bi_next = NULL;
 609 
 610         if (bl->tail)
 611                 bl->tail->bi_next = bio;
 612         else
 613                 bl->head = bio;
 614 
 615         bl->tail = bio;
 616 }
 617 
 618 static inline void bio_list_add_head(struct bio_list *bl, struct bio *bio)
 619 {
 620         bio->bi_next = bl->head;
 621 
 622         bl->head = bio;
 623 
 624         if (!bl->tail)
 625                 bl->tail = bio;
 626 }
 627 
 628 static inline void bio_list_merge(struct bio_list *bl, struct bio_list *bl2)
 629 {
 630         if (!bl2->head)
 631                 return;
 632 
 633         if (bl->tail)
 634                 bl->tail->bi_next = bl2->head;
 635         else
 636                 bl->head = bl2->head;
 637 
 638         bl->tail = bl2->tail;
 639 }
 640 
 641 static inline void bio_list_merge_head(struct bio_list *bl,
 642                                        struct bio_list *bl2)
 643 {
 644         if (!bl2->head)
 645                 return;
 646 
 647         if (bl->head)
 648                 bl2->tail->bi_next = bl->head;
 649         else
 650                 bl->tail = bl2->tail;
 651 
 652         bl->head = bl2->head;
 653 }
 654 
 655 static inline struct bio *bio_list_peek(struct bio_list *bl)
 656 {
 657         return bl->head;
 658 }
 659 
 660 static inline struct bio *bio_list_pop(struct bio_list *bl)
 661 {
 662         struct bio *bio = bl->head;
 663 
 664         if (bio) {
 665                 bl->head = bl->head->bi_next;
 666                 if (!bl->head)
 667                         bl->tail = NULL;
 668 
 669                 bio->bi_next = NULL;
 670         }
 671 
 672         return bio;
 673 }
 674 
 675 static inline struct bio *bio_list_get(struct bio_list *bl)
 676 {
 677         struct bio *bio = bl->head;
 678 
 679         bl->head = bl->tail = NULL;
 680 
 681         return bio;
 682 }
 683 
 684 /*
 685  * Increment chain count for the bio. Make sure the CHAIN flag update
 686  * is visible before the raised count.
 687  */
 688 static inline void bio_inc_remaining(struct bio *bio)
 689 {
 690         bio_set_flag(bio, BIO_CHAIN);
 691         smp_mb__before_atomic();
 692         atomic_inc(&bio->__bi_remaining);
 693 }
 694 
 695 /*
 696  * bio_set is used to allow other portions of the IO system to
 697  * allocate their own private memory pools for bio and iovec structures.
 698  * These memory pools in turn all allocate from the bio_slab
 699  * and the bvec_slabs[].
 700  */
 701 #define BIO_POOL_SIZE 2
 702 
 703 struct bio_set {
 704         struct kmem_cache *bio_slab;
 705         unsigned int front_pad;
 706 
 707         mempool_t bio_pool;
 708         mempool_t bvec_pool;
 709 #if defined(CONFIG_BLK_DEV_INTEGRITY)
 710         mempool_t bio_integrity_pool;
 711         mempool_t bvec_integrity_pool;
 712 #endif
 713 
 714         /*
 715          * Deadlock avoidance for stacking block drivers: see comments in
 716          * bio_alloc_bioset() for details
 717          */
 718         spinlock_t              rescue_lock;
 719         struct bio_list         rescue_list;
 720         struct work_struct      rescue_work;
 721         struct workqueue_struct *rescue_workqueue;
 722 };
 723 
 724 struct biovec_slab {
 725         int nr_vecs;
 726         char *name;
 727         struct kmem_cache *slab;
 728 };
 729 
 730 static inline bool bioset_initialized(struct bio_set *bs)
 731 {
 732         return bs->bio_slab != NULL;
 733 }
 734 
 735 /*
 736  * a small number of entries is fine, not going to be performance critical.
 737  * basically we just need to survive
 738  */
 739 #define BIO_SPLIT_ENTRIES 2
 740 
 741 #if defined(CONFIG_BLK_DEV_INTEGRITY)
 742 
 743 #define bip_for_each_vec(bvl, bip, iter)                                \
 744         for_each_bvec(bvl, (bip)->bip_vec, iter, (bip)->bip_iter)
 745 
 746 #define bio_for_each_integrity_vec(_bvl, _bio, _iter)                   \
 747         for_each_bio(_bio)                                              \
 748                 bip_for_each_vec(_bvl, _bio->bi_integrity, _iter)
 749 
 750 extern struct bio_integrity_payload *bio_integrity_alloc(struct bio *, gfp_t, unsigned int);
 751 extern int bio_integrity_add_page(struct bio *, struct page *, unsigned int, unsigned int);
 752 extern bool bio_integrity_prep(struct bio *);
 753 extern void bio_integrity_advance(struct bio *, unsigned int);
 754 extern void bio_integrity_trim(struct bio *);
 755 extern int bio_integrity_clone(struct bio *, struct bio *, gfp_t);
 756 extern int bioset_integrity_create(struct bio_set *, int);
 757 extern void bioset_integrity_free(struct bio_set *);
 758 extern void bio_integrity_init(void);
 759 
 760 #else /* CONFIG_BLK_DEV_INTEGRITY */
 761 
 762 static inline void *bio_integrity(struct bio *bio)
 763 {
 764         return NULL;
 765 }
 766 
 767 static inline int bioset_integrity_create(struct bio_set *bs, int pool_size)
 768 {
 769         return 0;
 770 }
 771 
 772 static inline void bioset_integrity_free (struct bio_set *bs)
 773 {
 774         return;
 775 }
 776 
 777 static inline bool bio_integrity_prep(struct bio *bio)
 778 {
 779         return true;
 780 }
 781 
 782 static inline int bio_integrity_clone(struct bio *bio, struct bio *bio_src,
 783                                       gfp_t gfp_mask)
 784 {
 785         return 0;
 786 }
 787 
 788 static inline void bio_integrity_advance(struct bio *bio,
 789                                          unsigned int bytes_done)
 790 {
 791         return;
 792 }
 793 
 794 static inline void bio_integrity_trim(struct bio *bio)
 795 {
 796         return;
 797 }
 798 
 799 static inline void bio_integrity_init(void)
 800 {
 801         return;
 802 }
 803 
 804 static inline bool bio_integrity_flagged(struct bio *bio, enum bip_flags flag)
 805 {
 806         return false;
 807 }
 808 
 809 static inline void *bio_integrity_alloc(struct bio * bio, gfp_t gfp,
 810                                                                 unsigned int nr)
 811 {
 812         return ERR_PTR(-EINVAL);
 813 }
 814 
 815 static inline int bio_integrity_add_page(struct bio *bio, struct page *page,
 816                                         unsigned int len, unsigned int offset)
 817 {
 818         return 0;
 819 }
 820 
 821 #endif /* CONFIG_BLK_DEV_INTEGRITY */
 822 
 823 /*
 824  * Mark a bio as polled. Note that for async polled IO, the caller must
 825  * expect -EWOULDBLOCK if we cannot allocate a request (or other resources).
 826  * We cannot block waiting for requests on polled IO, as those completions
 827  * must be found by the caller. This is different than IRQ driven IO, where
 828  * it's safe to wait for IO to complete.
 829  */
 830 static inline void bio_set_polled(struct bio *bio, struct kiocb *kiocb)
 831 {
 832         bio->bi_opf |= REQ_HIPRI;
 833         if (!is_sync_kiocb(kiocb))
 834                 bio->bi_opf |= REQ_NOWAIT;
 835 }
 836 
 837 #endif /* CONFIG_BLOCK */
 838 #endif /* __LINUX_BIO_H */
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