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