include/linux/bio.h

   1 /*
   2  * Copyright (C) 2001 Jens Axboe <axboe@suse.de>
   3  *
   4  * This program is free software; you can redistribute it and/or modify
   5  * it under the terms of the GNU General Public License version 2 as
   6  * published by the Free Software Foundation.
   7  *
   8  * This program is distributed in the hope that it will be useful,
   9  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  10  *
  11  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  12  * GNU General Public License for more details.
  13  *
  14  * You should have received a copy of the GNU General Public Licens
  15  * along with this program; if not, write to the Free Software
  16  * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-
  17  */
  18 #ifndef __LINUX_BIO_H
  19 #define __LINUX_BIO_H
  20
  21 #include <linux/highmem.h>
  22 #include <linux/mempool.h>
  23 #include <linux/ioprio.h>
  24 #include <linux/bug.h>
  25
  26 #ifdef CONFIG_BLOCK
  27
  28 #include <asm/io.h>
  29
  30 /* struct bio, bio_vec and BIO_* flags are defined in blk_types.h */
  31 #include <linux/blk_types.h>
  32
  33 #define BIO_DEBUG
  34
  35 #ifdef BIO_DEBUG
  36 #define BIO_BUG_ON      BUG_ON
  37 #else
  38 #define BIO_BUG_ON
  39 #endif
  40
  41 #ifdef CONFIG_THP_SWAP
  42 #if HPAGE_PMD_NR > 256
  43 #define BIO_MAX_PAGES           HPAGE_PMD_NR
  44 #else
  45 #define BIO_MAX_PAGES           256
  46 #endif
  47 #else
  48 #define BIO_MAX_PAGES           256
  49 #endif
  50
  51 #define bio_prio(bio)                   (bio)->bi_ioprio
  52 #define bio_set_prio(bio, prio)         ((bio)->bi_ioprio = prio)
  53
  54 #define bio_iter_iovec(bio, iter)                               \
  55         bvec_iter_bvec((bio)->bi_io_vec, (iter))
  56
  57 #define bio_iter_page(bio, iter)                                \
  58         bvec_iter_page((bio)->bi_io_vec, (iter))
  59 #define bio_iter_len(bio, iter)                                 \
  60         bvec_iter_len((bio)->bi_io_vec, (iter))
  61 #define bio_iter_offset(bio, iter)                              \
  62         bvec_iter_offset((bio)->bi_io_vec, (iter))
  63
  64 #define bio_page(bio)           bio_iter_page((bio), (bio)->bi_iter)
  65 #define bio_offset(bio)         bio_iter_offset((bio), (bio)->bi_iter)
  66 #define bio_iovec(bio)          bio_iter_iovec((bio), (bio)->bi_iter)
  67
  68 #define bio_multiple_segments(bio)                              \
  69         ((bio)->bi_iter.bi_size != bio_iovec(bio).bv_len)
  70 #define bio_sectors(bio)        ((bio)->bi_iter.bi_size >> 9)
  71 #define bio_end_sector(bio)     ((bio)->bi_iter.bi_sector + bio_sectors((bio)))
  72
  73 /*
  74  * Return the data direction, READ or WRITE.
  75  */
  76 #define bio_data_dir(bio) \
  77         (op_is_write(bio_op(bio)) ? WRITE : READ)
  78
  79 /*
  80  * Check whether this bio carries any data or not. A NULL bio is allowed.
  81  */
  82 static inline bool bio_has_data(struct bio *bio)
  83 {
  84         if (bio &&
  85             bio->bi_iter.bi_size &&
  86             bio_op(bio) != REQ_OP_DISCARD &&
  87             bio_op(bio) != REQ_OP_SECURE_ERASE &&
  88             bio_op(bio) != REQ_OP_WRITE_ZEROES)
  89                 return true;
  90
  91         return false;
  92 }
  93
  94 static inline bool bio_no_advance_iter(struct bio *bio)
  95 {
  96         return bio_op(bio) == REQ_OP_DISCARD ||
  97                bio_op(bio) == REQ_OP_SECURE_ERASE ||
  98                bio_op(bio) == REQ_OP_WRITE_SAME ||
  99                bio_op(bio) == REQ_OP_WRITE_ZEROES;
 100 }
 101
 102 static inline bool bio_mergeable(struct bio *bio)
 103 {
 104         if (bio->bi_opf & REQ_NOMERGE_FLAGS)
 105                 return false;
 106
 107         return true;
 108 }
 109
 110 static inline unsigned int bio_cur_bytes(struct bio *bio)
 111 {
 112         if (bio_has_data(bio))
 113                 return bio_iovec(bio).bv_len;
 114         else /* dataless requests such as discard */
 115                 return bio->bi_iter.bi_size;
 116 }
 117
 118 static inline void *bio_data(struct bio *bio)
 119 {
 120         if (bio_has_data(bio))
 121                 return page_address(bio_page(bio)) + bio_offset(bio);
 122
 123         return NULL;
 124 }
 125
 126 /*
 127  * will die
 128  */
 129 #define bvec_to_phys(bv)        (page_to_phys((bv)->bv_page) + (unsigned long) (bv)->bv_offset)
 130
 131 /*
 132  * merge helpers etc
 133  */
 134
 135 /* Default implementation of BIOVEC_PHYS_MERGEABLE */
 136 #define __BIOVEC_PHYS_MERGEABLE(vec1, vec2)     \
 137         ((bvec_to_phys((vec1)) + (vec1)->bv_len) == bvec_to_phys((vec2)))
 138
 139 /*
 140  * allow arch override, for eg virtualized architectures (put in asm/io.h)
 141  */
 142 #ifndef BIOVEC_PHYS_MERGEABLE
 143 #define BIOVEC_PHYS_MERGEABLE(vec1, vec2)       \
 144         __BIOVEC_PHYS_MERGEABLE(vec1, vec2)
 145 #endif
 146
 147 #define __BIO_SEG_BOUNDARY(addr1, addr2, mask) \
 148         (((addr1) | (mask)) == (((addr2) - 1) | (mask)))
 149 #define BIOVEC_SEG_BOUNDARY(q, b1, b2) \
 150         __BIO_SEG_BOUNDARY(bvec_to_phys((b1)), bvec_to_phys((b2)) + (b2)->bv_len, queue_segment_boundary((q)))
 151
 152 /*
 153  * drivers should _never_ use the all version - the bio may have been split
 154  * before it got to the driver and the driver won't own all of it
 155  */
 156 #define bio_for_each_segment_all(bvl, bio, i)                           \
 157         for (i = 0, bvl = (bio)->bi_io_vec; i < (bio)->bi_vcnt; i++, bvl++)
 158
 159 static inline void bio_advance_iter(struct bio *bio, struct bvec_iter *iter,
 160                                     unsigned bytes)
 161 {
 162         iter->bi_sector += bytes >> 9;
 163
 164         if (bio_no_advance_iter(bio)) {
 165                 iter->bi_size -= bytes;
 166                 iter->bi_done += bytes;
 167         } else {
 168                 bvec_iter_advance(bio->bi_io_vec, iter, bytes);
 169                 /* TODO: It is reasonable to complete bio with error here. */
 170         }
 171 }
 172
 173 static inline bool bio_rewind_iter(struct bio *bio, struct bvec_iter *iter,
 174                 unsigned int bytes)
 175 {
 176         iter->bi_sector -= bytes >> 9;
 177
 178         if (bio_no_advance_iter(bio)) {
 179                 iter->bi_size += bytes;
 180                 iter->bi_done -= bytes;
 181                 return true;
 182         }
 183
 184         return bvec_iter_rewind(bio->bi_io_vec, iter, bytes);
 185 }
 186
 187 #define __bio_for_each_segment(bvl, bio, iter, start)                   \
 188         for (iter = (start);                                            \
 189              (iter).bi_size &&                                          \
 190                 ((bvl = bio_iter_iovec((bio), (iter))), 1);             \
 191              bio_advance_iter((bio), &(iter), (bvl).bv_len))
 192
 193 #define bio_for_each_segment(bvl, bio, iter)                            \
 194         __bio_for_each_segment(bvl, bio, iter, (bio)->bi_iter)
 195
 196 #define bio_iter_last(bvec, iter) ((iter).bi_size == (bvec).bv_len)
 197
 198 static inline unsigned bio_segments(struct bio *bio)
 199 {
 200         unsigned segs = 0;
 201         struct bio_vec bv;
 202         struct bvec_iter iter;
 203
 204         /*
 205          * We special case discard/write same/write zeroes, because they
 206          * interpret bi_size differently:
 207          */
 208
 209         switch (bio_op(bio)) {
 210         case REQ_OP_DISCARD:
 211         case REQ_OP_SECURE_ERASE:
 212         case REQ_OP_WRITE_ZEROES:
 213                 return 0;
 214         case REQ_OP_WRITE_SAME:
 215                 return 1;
 216         default:
 217                 break;
 218         }
 219
 220         bio_for_each_segment(bv, bio, iter)
 221                 segs++;
 222
 223         return segs;
 224 }
 225
 226 /*
 227  * get a reference to a bio, so it won't disappear. the intended use is
 228  * something like:
 229  *
 230  * bio_get(bio);
 231  * submit_bio(rw, bio);
 232  * if (bio->bi_flags ...)
 233  *      do_something
 234  * bio_put(bio);
 235  *
 236  * without the bio_get(), it could potentially complete I/O before submit_bio
 237  * returns. and then bio would be freed memory when if (bio->bi_flags ...)
 238  * runs
 239  */
 240 static inline void bio_get(struct bio *bio)
 241 {
 242         bio->bi_flags |= (1 << BIO_REFFED);
 243         smp_mb__before_atomic();
 244         atomic_inc(&bio->__bi_cnt);
 245 }
 246
 247 static inline void bio_cnt_set(struct bio *bio, unsigned int count)
 248 {
 249         if (count != 1) {
 250                 bio->bi_flags |= (1 << BIO_REFFED);
 251                 smp_mb__before_atomic();
 252         }
 253         atomic_set(&bio->__bi_cnt, count);
 254 }
 255
 256 static inline bool bio_flagged(struct bio *bio, unsigned int bit)
 257 {
 258         return (bio->bi_flags & (1U << bit)) != 0;
 259 }
 260
 261 static inline void bio_set_flag(struct bio *bio, unsigned int bit)
 262 {
 263         bio->bi_flags |= (1U << bit);
 264 }
 265
 266 static inline void bio_clear_flag(struct bio *bio, unsigned int bit)
 267 {
 268         bio->bi_flags &= ~(1U << bit);
 269 }
 270
 271 static inline void bio_get_first_bvec(struct bio *bio, struct bio_vec *bv)
 272 {
 273         *bv = bio_iovec(bio);
 274 }
 275
 276 static inline void bio_get_last_bvec(struct bio *bio, struct bio_vec *bv)
 277 {
 278         struct bvec_iter iter = bio->bi_iter;
 279         int idx;
 280
 281         if (unlikely(!bio_multiple_segments(bio))) {
 282                 *bv = bio_iovec(bio);
 283                 return;
 284         }
 285
 286         bio_advance_iter(bio, &iter, iter.bi_size);
 287
 288         if (!iter.bi_bvec_done)
 289                 idx = iter.bi_idx - 1;
 290         else    /* in the middle of bvec */
 291                 idx = iter.bi_idx;
 292
 293         *bv = bio->bi_io_vec[idx];
 294
 295         /*
 296          * iter.bi_bvec_done records actual length of the last bvec
 297          * if this bio ends in the middle of one io vector
 298          */
 299         if (iter.bi_bvec_done)
 300                 bv->bv_len = iter.bi_bvec_done;
 301 }
 302
 303 enum bip_flags {
 304         BIP_BLOCK_INTEGRITY     = 1 << 0, /* block layer owns integrity data */
 305         BIP_MAPPED_INTEGRITY    = 1 << 1, /* ref tag has been remapped */
 306         BIP_CTRL_NOCHECK        = 1 << 2, /* disable HBA integrity checking */
 307         BIP_DISK_NOCHECK        = 1 << 3, /* disable disk integrity checking */
 308         BIP_IP_CHECKSUM         = 1 << 4, /* IP checksum */
 309 };
 310
 311 /*
 312  * bio integrity payload
 313  */
 314 struct bio_integrity_payload {
 315         struct bio              *bip_bio;       /* parent bio */
 316
 317         struct bvec_iter        bip_iter;
 318
 319         unsigned short          bip_slab;       /* slab the bip came from */
 320         unsigned short          bip_vcnt;       /* # of integrity bio_vecs */
 321         unsigned short          bip_max_vcnt;   /* integrity bio_vec slots */
 322         unsigned short          bip_flags;      /* control flags */
 323
 324         struct work_struct      bip_work;       /* I/O completion */
 325
 326         struct bio_vec          *bip_vec;
 327         struct bio_vec          bip_inline_vecs[0];/* embedded bvec array */
 328 };
 329
 330 #if defined(CONFIG_BLK_DEV_INTEGRITY)
 331
 332 static inline struct bio_integrity_payload *bio_integrity(struct bio *bio)
 333 {
 334         if (bio->bi_opf & REQ_INTEGRITY)
 335                 return bio->bi_integrity;
 336
 337         return NULL;
 338 }
 339
 340 static inline bool bio_integrity_flagged(struct bio *bio, enum bip_flags flag)
 341 {
 342         struct bio_integrity_payload *bip = bio_integrity(bio);
 343
 344         if (bip)
 345                 return bip->bip_flags & flag;
 346
 347         return false;
 348 }
 349
 350 static inline sector_t bip_get_seed(struct bio_integrity_payload *bip)
 351 {
 352         return bip->bip_iter.bi_sector;
 353 }
 354
 355 static inline void bip_set_seed(struct bio_integrity_payload *bip,
 356                                 sector_t seed)
 357 {
 358         bip->bip_iter.bi_sector = seed;
 359 }
 360
 361 #endif /* CONFIG_BLK_DEV_INTEGRITY */
 362
 363 extern void bio_trim(struct bio *bio, int offset, int size);
 364 extern struct bio *bio_split(struct bio *bio, int sectors,
 365                              gfp_t gfp, struct bio_set *bs);
 366
 367 /**
 368  * bio_next_split - get next @sectors from a bio, splitting if necessary
 369  * @bio:        bio to split
 370  * @sectors:    number of sectors to split from the front of @bio
 371  * @gfp:        gfp mask
 372  * @bs:         bio set to allocate from
 373  *
 374  * Returns a bio representing the next @sectors of @bio - if the bio is smaller
 375  * than @sectors, returns the original bio unchanged.
 376  */
 377 static inline struct bio *bio_next_split(struct bio *bio, int sectors,
 378                                          gfp_t gfp, struct bio_set *bs)
 379 {
 380         if (sectors >= bio_sectors(bio))
 381                 return bio;
 382
 383         return bio_split(bio, sectors, gfp, bs);
 384 }
 385
 386 extern struct bio_set *bioset_create(unsigned int, unsigned int, int flags);
 387 enum {
 388         BIOSET_NEED_BVECS = BIT(0),
 389         BIOSET_NEED_RESCUER = BIT(1),
 390 };
 391 extern void bioset_free(struct bio_set *);
 392 extern mempool_t *biovec_create_pool(int pool_entries);
 393
 394 extern struct bio *bio_alloc_bioset(gfp_t, unsigned int, struct bio_set *);
 395 extern void bio_put(struct bio *);
 396
 397 extern void __bio_clone_fast(struct bio *, struct bio *);
 398 extern struct bio *bio_clone_fast(struct bio *, gfp_t, struct bio_set *);
 399 extern struct bio *bio_clone_bioset(struct bio *, gfp_t, struct bio_set *bs);
 400
 401 extern struct bio_set *fs_bio_set;
 402
 403 static inline struct bio *bio_alloc(gfp_t gfp_mask, unsigned int nr_iovecs)
 404 {
 405         return bio_alloc_bioset(gfp_mask, nr_iovecs, fs_bio_set);
 406 }
 407
 408 static inline struct bio *bio_kmalloc(gfp_t gfp_mask, unsigned int nr_iovecs)
 409 {
 410         return bio_alloc_bioset(gfp_mask, nr_iovecs, NULL);
 411 }
 412
 413 static inline struct bio *bio_clone_kmalloc(struct bio *bio, gfp_t gfp_mask)
 414 {
 415         return bio_clone_bioset(bio, gfp_mask, NULL);
 416
 417 }
 418
 419 extern blk_qc_t submit_bio(struct bio *);
 420
 421 extern void bio_endio(struct bio *);
 422
 423 static inline void bio_io_error(struct bio *bio)
 424 {
 425         bio->bi_status = BLK_STS_IOERR;
 426         bio_endio(bio);
 427 }
 428
 429 static inline void bio_wouldblock_error(struct bio *bio)
 430 {
 431         bio->bi_status = BLK_STS_AGAIN;
 432         bio_endio(bio);
 433 }
 434
 435 struct request_queue;
 436 extern int bio_phys_segments(struct request_queue *, struct bio *);
 437
 438 extern int submit_bio_wait(struct bio *bio);
 439 extern void bio_advance(struct bio *, unsigned);
 440
 441 extern void bio_init(struct bio *bio, struct bio_vec *table,
 442                      unsigned short max_vecs);
 443 extern void bio_uninit(struct bio *);
 444 extern void bio_reset(struct bio *);
 445 void bio_chain(struct bio *, struct bio *);
 446
 447 extern int bio_add_page(struct bio *, struct page *, unsigned int,unsigned int);
 448 extern int bio_add_pc_page(struct request_queue *, struct bio *, struct page *,
 449                            unsigned int, unsigned int);
 450 int bio_iov_iter_get_pages(struct bio *bio, struct iov_iter *iter);
 451 struct rq_map_data;
 452 extern struct bio *bio_map_user_iov(struct request_queue *,
 453                                     struct iov_iter *, gfp_t);
 454 extern void bio_unmap_user(struct bio *);
 455 extern struct bio *bio_map_kern(struct request_queue *, void *, unsigned int,
 456                                 gfp_t);
 457 extern struct bio *bio_copy_kern(struct request_queue *, void *, unsigned int,
 458                                  gfp_t, int);
 459 extern void bio_set_pages_dirty(struct bio *bio);
 460 extern void bio_check_pages_dirty(struct bio *bio);
 461
 462 void generic_start_io_acct(struct request_queue *q, int rw,
 463                                 unsigned long sectors, struct hd_struct *part);
 464 void generic_end_io_acct(struct request_queue *q, int rw,
 465                                 struct hd_struct *part,
 466                                 unsigned long start_time);
 467
 468 #ifndef ARCH_IMPLEMENTS_FLUSH_DCACHE_PAGE
 469 # error "You should define ARCH_IMPLEMENTS_FLUSH_DCACHE_PAGE for your platform"
 470 #endif
 471 #if ARCH_IMPLEMENTS_FLUSH_DCACHE_PAGE
 472 extern void bio_flush_dcache_pages(struct bio *bi);
 473 #else
 474 static inline void bio_flush_dcache_pages(struct bio *bi)
 475 {
 476 }
 477 #endif
 478
 479 extern void bio_copy_data(struct bio *dst, struct bio *src);
 480 extern int bio_alloc_pages(struct bio *bio, gfp_t gfp);
 481 extern void bio_free_pages(struct bio *bio);
 482
 483 extern struct bio *bio_copy_user_iov(struct request_queue *,
 484                                      struct rq_map_data *,
 485                                      struct iov_iter *,
 486                                      gfp_t);
 487 extern int bio_uncopy_user(struct bio *);
 488 void zero_fill_bio(struct bio *bio);
 489 extern struct bio_vec *bvec_alloc(gfp_t, int, unsigned long *, mempool_t *);
 490 extern void bvec_free(mempool_t *, struct bio_vec *, unsigned int);
 491 extern unsigned int bvec_nr_vecs(unsigned short idx);
 492
 493 #define bio_set_dev(bio, bdev)                  \
 494 do {                                            \
 495         if ((bio)->bi_disk != (bdev)->bd_disk)  \
 496                 bio_clear_flag(bio, BIO_THROTTLED);\
 497         (bio)->bi_disk = (bdev)->bd_disk;       \
 498         (bio)->bi_partno = (bdev)->bd_partno;   \
 499 } while (0)
 500
 501 #define bio_copy_dev(dst, src)                  \
 502 do {                                            \
 503         (dst)->bi_disk = (src)->bi_disk;        \
 504         (dst)->bi_partno = (src)->bi_partno;    \
 505 } while (0)
 506
 507 #define bio_dev(bio) \
 508         disk_devt((bio)->bi_disk)
 509
 510 #define bio_devname(bio, buf) \
 511         __bdevname(bio_dev(bio), (buf))
 512
 513 #ifdef CONFIG_BLK_CGROUP
 514 int bio_associate_blkcg(struct bio *bio, struct cgroup_subsys_state *blkcg_css);
 515 void bio_disassociate_task(struct bio *bio);
 516 void bio_clone_blkcg_association(struct bio *dst, struct bio *src);
 517 #else   /* CONFIG_BLK_CGROUP */
 518 static inline int bio_associate_blkcg(struct bio *bio,
 519                         struct cgroup_subsys_state *blkcg_css) { return 0; }
 520 static inline void bio_disassociate_task(struct bio *bio) { }
 521 static inline void bio_clone_blkcg_association(struct bio *dst,
 522                         struct bio *src) { }
 523 #endif  /* CONFIG_BLK_CGROUP */
 524
 525 #ifdef CONFIG_HIGHMEM
 526 /*
 527  * remember never ever reenable interrupts between a bvec_kmap_irq and
 528  * bvec_kunmap_irq!
 529  */
 530 static inline char *bvec_kmap_irq(struct bio_vec *bvec, unsigned long *flags)
 531 {
 532         unsigned long addr;
 533
 534         /*
 535          * might not be a highmem page, but the preempt/irq count
 536          * balancing is a lot nicer this way
 537          */
 538         local_irq_save(*flags);
 539         addr = (unsigned long) kmap_atomic(bvec->bv_page);
 540
 541         BUG_ON(addr & ~PAGE_MASK);
 542
 543         return (char *) addr + bvec->bv_offset;
 544 }
 545
 546 static inline void bvec_kunmap_irq(char *buffer, unsigned long *flags)
 547 {
 548         unsigned long ptr = (unsigned long) buffer & PAGE_MASK;
 549
 550         kunmap_atomic((void *) ptr);
 551         local_irq_restore(*flags);
 552 }
 553
 554 #else
 555 static inline char *bvec_kmap_irq(struct bio_vec *bvec, unsigned long *flags)
 556 {
 557         return page_address(bvec->bv_page) + bvec->bv_offset;
 558 }
 559
 560 static inline void bvec_kunmap_irq(char *buffer, unsigned long *flags)
 561 {
 562         *flags = 0;
 563 }
 564 #endif
 565
 566 /*
 567  * BIO list management for use by remapping drivers (e.g. DM or MD) and loop.
 568  *
 569  * A bio_list anchors a singly-linked list of bios chained through the bi_next
 570  * member of the bio.  The bio_list also caches the last list member to allow
 571  * fast access to the tail.
 572  */
 573 struct bio_list {
 574         struct bio *head;
 575         struct bio *tail;
 576 };
 577
 578 static inline int bio_list_empty(const struct bio_list *bl)
 579 {
 580         return bl->head == NULL;
 581 }
 582
 583 static inline void bio_list_init(struct bio_list *bl)
 584 {
 585         bl->head = bl->tail = NULL;
 586 }
 587
 588 #define BIO_EMPTY_LIST  { NULL, NULL }
 589
 590 #define bio_list_for_each(bio, bl) \
 591         for (bio = (bl)->head; bio; bio = bio->bi_next)
 592
 593 static inline unsigned bio_list_size(const struct bio_list *bl)
 594 {
 595         unsigned sz = 0;
 596         struct bio *bio;
 597
 598         bio_list_for_each(bio, bl)
 599                 sz++;
 600
 601         return sz;
 602 }
 603
 604 static inline void bio_list_add(struct bio_list *bl, struct bio *bio)
 605 {
 606         bio->bi_next = NULL;
 607
 608         if (bl->tail)
 609                 bl->tail->bi_next = bio;
 610         else
 611                 bl->head = bio;
 612
 613         bl->tail = bio;
 614 }
 615
 616 static inline void bio_list_add_head(struct bio_list *bl, struct bio *bio)
 617 {
 618         bio->bi_next = bl->head;
 619
 620         bl->head = bio;
 621
 622         if (!bl->tail)
 623                 bl->tail = bio;
 624 }
 625
 626 static inline void bio_list_merge(struct bio_list *bl, struct bio_list *bl2)
 627 {
 628         if (!bl2->head)
 629                 return;
 630
 631         if (bl->tail)
 632                 bl->tail->bi_next = bl2->head;
 633         else
 634                 bl->head = bl2->head;
 635
 636         bl->tail = bl2->tail;
 637 }
 638
 639 static inline void bio_list_merge_head(struct bio_list *bl,
 640                                        struct bio_list *bl2)
 641 {
 642         if (!bl2->head)
 643                 return;
 644
 645         if (bl->head)
 646                 bl2->tail->bi_next = bl->head;
 647         else
 648                 bl->tail = bl2->tail;
 649
 650         bl->head = bl2->head;
 651 }
 652
 653 static inline struct bio *bio_list_peek(struct bio_list *bl)
 654 {
 655         return bl->head;
 656 }
 657
 658 static inline struct bio *bio_list_pop(struct bio_list *bl)
 659 {
 660         struct bio *bio = bl->head;
 661
 662         if (bio) {
 663                 bl->head = bl->head->bi_next;
 664                 if (!bl->head)
 665                         bl->tail = NULL;
 666
 667                 bio->bi_next = NULL;
 668         }
 669
 670         return bio;
 671 }
 672
 673 static inline struct bio *bio_list_get(struct bio_list *bl)
 674 {
 675         struct bio *bio = bl->head;
 676
 677         bl->head = bl->tail = NULL;
 678
 679         return bio;
 680 }
 681
 682 /*
 683  * Increment chain count for the bio. Make sure the CHAIN flag update
 684  * is visible before the raised count.
 685  */
 686 static inline void bio_inc_remaining(struct bio *bio)
 687 {
 688         bio_set_flag(bio, BIO_CHAIN);
 689         smp_mb__before_atomic();
 690         atomic_inc(&bio->__bi_remaining);
 691 }
 692
 693 /*
 694  * bio_set is used to allow other portions of the IO system to
 695  * allocate their own private memory pools for bio and iovec structures.
 696  * These memory pools in turn all allocate from the bio_slab
 697  * and the bvec_slabs[].
 698  */
 699 #define BIO_POOL_SIZE 2
 700
 701 struct bio_set {
 702         struct kmem_cache *bio_slab;
 703         unsigned int front_pad;
 704
 705         mempool_t *bio_pool;
 706         mempool_t *bvec_pool;
 707 #if defined(CONFIG_BLK_DEV_INTEGRITY)
 708         mempool_t *bio_integrity_pool;
 709         mempool_t *bvec_integrity_pool;
 710 #endif
 711
 712         /*
 713          * Deadlock avoidance for stacking block drivers: see comments in
 714          * bio_alloc_bioset() for details
 715          */
 716         spinlock_t              rescue_lock;
 717         struct bio_list         rescue_list;
 718         struct work_struct      rescue_work;
 719         struct workqueue_struct *rescue_workqueue;
 720 };
 721
 722 struct biovec_slab {
 723         int nr_vecs;
 724         char *name;
 725         struct kmem_cache *slab;
 726 };
 727
 728 /*
 729  * a small number of entries is fine, not going to be performance critical.
 730  * basically we just need to survive
 731  */
 732 #define BIO_SPLIT_ENTRIES 2
 733
 734 #if defined(CONFIG_BLK_DEV_INTEGRITY)
 735
 736 #define bip_for_each_vec(bvl, bip, iter)                                \
 737         for_each_bvec(bvl, (bip)->bip_vec, iter, (bip)->bip_iter)
 738
 739 #define bio_for_each_integrity_vec(_bvl, _bio, _iter)                   \
 740         for_each_bio(_bio)                                              \
 741                 bip_for_each_vec(_bvl, _bio->bi_integrity, _iter)
 742
 743 extern struct bio_integrity_payload *bio_integrity_alloc(struct bio *, gfp_t, unsigned int);
 744 extern int bio_integrity_add_page(struct bio *, struct page *, unsigned int, unsigned int);
 745 extern bool bio_integrity_prep(struct bio *);
 746 extern void bio_integrity_advance(struct bio *, unsigned int);
 747 extern void bio_integrity_trim(struct bio *);
 748 extern int bio_integrity_clone(struct bio *, struct bio *, gfp_t);
 749 extern int bioset_integrity_create(struct bio_set *, int);
 750 extern void bioset_integrity_free(struct bio_set *);
 751 extern void bio_integrity_init(void);
 752
 753 #else /* CONFIG_BLK_DEV_INTEGRITY */
 754
 755 static inline void *bio_integrity(struct bio *bio)
 756 {
 757         return NULL;
 758 }
 759
 760 static inline int bioset_integrity_create(struct bio_set *bs, int pool_size)
 761 {
 762         return 0;
 763 }
 764
 765 static inline void bioset_integrity_free (struct bio_set *bs)
 766 {
 767         return;
 768 }
 769
 770 static inline bool bio_integrity_prep(struct bio *bio)
 771 {
 772         return true;
 773 }
 774
 775 static inline int bio_integrity_clone(struct bio *bio, struct bio *bio_src,
 776                                       gfp_t gfp_mask)
 777 {
 778         return 0;
 779 }
 780
 781 static inline void bio_integrity_advance(struct bio *bio,
 782                                          unsigned int bytes_done)
 783 {
 784         return;
 785 }
 786
 787 static inline void bio_integrity_trim(struct bio *bio)
 788 {
 789         return;
 790 }
 791
 792 static inline void bio_integrity_init(void)
 793 {
 794         return;
 795 }
 796
 797 static inline bool bio_integrity_flagged(struct bio *bio, enum bip_flags flag)
 798 {
 799         return false;
 800 }
 801
 802 static inline void *bio_integrity_alloc(struct bio * bio, gfp_t gfp,
 803                                                                 unsigned int nr)
 804 {
 805         return ERR_PTR(-EINVAL);
 806 }
 807
 808 static inline int bio_integrity_add_page(struct bio *bio, struct page *page,
 809                                         unsigned int len, unsigned int offset)
 810 {
 811         return 0;
 812 }
 813
 814 #endif /* CONFIG_BLK_DEV_INTEGRITY */
 815
 816 #endif /* CONFIG_BLOCK */
 817 #endif /* __LINUX_BIO_H */