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, struct bvec_iter *bvec)
 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, *bvec)
 209                segs++;
 210
 211        return segs;
 212}
 213
 214static inline unsigned bio_segments(struct bio *bio)
 215{
 216        return __bio_segments(bio, &bio->bi_iter);
 217}
 218
 219/*
 220 * get a reference to a bio, so it won't disappear. the intended use is
 221 * something like:
 222 *
 223 * bio_get(bio);
 224 * submit_bio(rw, bio);
 225 * if (bio->bi_flags ...)
 226 *      do_something
 227 * bio_put(bio);
 228 *
 229 * without the bio_get(), it could potentially complete I/O before submit_bio
 230 * returns. and then bio would be freed memory when if (bio->bi_flags ...)
 231 * runs
 232 */
 233static inline void bio_get(struct bio *bio)
 234{
 235        bio->bi_flags |= (1 << BIO_REFFED);
 236        smp_mb__before_atomic();
 237        atomic_inc(&bio->__bi_cnt);
 238}
 239
 240static inline void bio_cnt_set(struct bio *bio, unsigned int count)
 241{
 242        if (count != 1) {
 243                bio->bi_flags |= (1 << BIO_REFFED);
 244                smp_mb__before_atomic();
 245        }
 246        atomic_set(&bio->__bi_cnt, count);
 247}
 248
 249static inline bool bio_flagged(struct bio *bio, unsigned int bit)
 250{
 251        return (bio->bi_flags & (1U << bit)) != 0;
 252}
 253
 254static inline void bio_set_flag(struct bio *bio, unsigned int bit)
 255{
 256        bio->bi_flags |= (1U << bit);
 257}
 258
 259static inline void bio_clear_flag(struct bio *bio, unsigned int bit)
 260{
 261        bio->bi_flags &= ~(1U << bit);
 262}
 263
 264static inline void bio_get_first_bvec(struct bio *bio, struct bio_vec *bv)
 265{
 266        *bv = bio_iovec(bio);
 267}
 268
 269static inline void bio_get_last_bvec(struct bio *bio, struct bio_vec *bv)
 270{
 271        struct bvec_iter iter = bio->bi_iter;
 272        int idx;
 273
 274        if (unlikely(!bio_multiple_segments(bio))) {
 275                *bv = bio_iovec(bio);
 276                return;
 277        }
 278
 279        bio_advance_iter(bio, &iter, iter.bi_size);
 280
 281        if (!iter.bi_bvec_done)
 282                idx = iter.bi_idx - 1;
 283        else    /* in the middle of bvec */
 284                idx = iter.bi_idx;
 285
 286        *bv = bio->bi_io_vec[idx];
 287
 288        /*
 289         * iter.bi_bvec_done records actual length of the last bvec
 290         * if this bio ends in the middle of one io vector
 291         */
 292        if (iter.bi_bvec_done)
 293                bv->bv_len = iter.bi_bvec_done;
 294}
 295
 296enum 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 */
 307struct bio_integrity_payload {
 308        struct bio              *bip_bio;       /* parent bio */
 309
 310        struct bvec_iter        bip_iter;
 311
 312        bio_end_io_t            *bip_end_io;    /* saved I/O completion fn */
 313
 314        unsigned short          bip_slab;       /* slab the bip came from */
 315        unsigned short          bip_vcnt;       /* # of integrity bio_vecs */
 316        unsigned short          bip_max_vcnt;   /* integrity bio_vec slots */
 317        unsigned short          bip_flags;      /* control flags */
 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
 327static 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
 335static 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
 345static inline sector_t bip_get_seed(struct bio_integrity_payload *bip)
 346{
 347        return bip->bip_iter.bi_sector;
 348}
 349
 350static 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
 358extern void bio_trim(struct bio *bio, int offset, int size);
 359extern 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 */
 372static 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
 381extern struct bio_set *bioset_create(unsigned int, unsigned int);
 382extern struct bio_set *bioset_create_nobvec(unsigned int, unsigned int);
 383extern void bioset_free(struct bio_set *);
 384extern mempool_t *biovec_create_pool(int pool_entries);
 385
 386extern struct bio *bio_alloc_bioset(gfp_t, int, struct bio_set *);
 387extern void bio_put(struct bio *);
 388
 389extern void __bio_clone_fast(struct bio *, struct bio *);
 390extern struct bio *bio_clone_fast(struct bio *, gfp_t, struct bio_set *);
 391extern struct bio *bio_clone_bioset(struct bio *, gfp_t, struct bio_set *bs);
 392extern struct bio *bio_clone_bioset_partial(struct bio *, gfp_t,
 393                                            struct bio_set *, int, int);
 394
 395extern struct bio_set *fs_bio_set;
 396
 397static inline struct bio *bio_alloc(gfp_t gfp_mask, unsigned int nr_iovecs)
 398{
 399        return bio_alloc_bioset(gfp_mask, nr_iovecs, fs_bio_set);
 400}
 401
 402static inline struct bio *bio_clone(struct bio *bio, gfp_t gfp_mask)
 403{
 404        return bio_clone_bioset(bio, gfp_mask, fs_bio_set);
 405}
 406
 407static inline struct bio *bio_kmalloc(gfp_t gfp_mask, unsigned int nr_iovecs)
 408{
 409        return bio_alloc_bioset(gfp_mask, nr_iovecs, NULL);
 410}
 411
 412static inline struct bio *bio_clone_kmalloc(struct bio *bio, gfp_t gfp_mask)
 413{
 414        return bio_clone_bioset(bio, gfp_mask, NULL);
 415
 416}
 417
 418extern blk_qc_t submit_bio(struct bio *);
 419
 420extern void bio_endio(struct bio *);
 421
 422static inline void bio_io_error(struct bio *bio)
 423{
 424        bio->bi_error = -EIO;
 425        bio_endio(bio);
 426}
 427
 428struct request_queue;
 429extern int bio_phys_segments(struct request_queue *, struct bio *);
 430
 431extern int submit_bio_wait(struct bio *bio);
 432extern void bio_advance(struct bio *, unsigned);
 433
 434extern void bio_init(struct bio *bio, struct bio_vec *table,
 435                     unsigned short max_vecs);
 436extern void bio_reset(struct bio *);
 437void bio_chain(struct bio *, struct bio *);
 438
 439extern int bio_add_page(struct bio *, struct page *, unsigned int,unsigned int);
 440extern int bio_add_pc_page(struct request_queue *, struct bio *, struct page *,
 441                           unsigned int, unsigned int);
 442int bio_iov_iter_get_pages(struct bio *bio, struct iov_iter *iter);
 443struct rq_map_data;
 444extern struct bio *bio_map_user_iov(struct request_queue *,
 445                                    const struct iov_iter *, gfp_t);
 446extern void bio_unmap_user(struct bio *);
 447extern struct bio *bio_map_kern(struct request_queue *, void *, unsigned int,
 448                                gfp_t);
 449extern struct bio *bio_copy_kern(struct request_queue *, void *, unsigned int,
 450                                 gfp_t, int);
 451extern void bio_set_pages_dirty(struct bio *bio);
 452extern void bio_check_pages_dirty(struct bio *bio);
 453
 454void generic_start_io_acct(int rw, unsigned long sectors,
 455                           struct hd_struct *part);
 456void generic_end_io_acct(int rw, struct hd_struct *part,
 457                         unsigned long start_time);
 458
 459#ifndef ARCH_IMPLEMENTS_FLUSH_DCACHE_PAGE
 460# error "You should define ARCH_IMPLEMENTS_FLUSH_DCACHE_PAGE for your platform"
 461#endif
 462#if ARCH_IMPLEMENTS_FLUSH_DCACHE_PAGE
 463extern void bio_flush_dcache_pages(struct bio *bi);
 464#else
 465static inline void bio_flush_dcache_pages(struct bio *bi)
 466{
 467}
 468#endif
 469
 470extern void bio_copy_data(struct bio *dst, struct bio *src);
 471extern int bio_alloc_pages(struct bio *bio, gfp_t gfp);
 472extern void bio_free_pages(struct bio *bio);
 473
 474extern struct bio *bio_copy_user_iov(struct request_queue *,
 475                                     struct rq_map_data *,
 476                                     const struct iov_iter *,
 477                                     gfp_t);
 478extern int bio_uncopy_user(struct bio *);
 479void zero_fill_bio(struct bio *bio);
 480extern struct bio_vec *bvec_alloc(gfp_t, int, unsigned long *, mempool_t *);
 481extern void bvec_free(mempool_t *, struct bio_vec *, unsigned int);
 482extern unsigned int bvec_nr_vecs(unsigned short idx);
 483
 484#ifdef CONFIG_BLK_CGROUP
 485int bio_associate_blkcg(struct bio *bio, struct cgroup_subsys_state *blkcg_css);
 486int bio_associate_current(struct bio *bio);
 487void bio_disassociate_task(struct bio *bio);
 488void bio_clone_blkcg_association(struct bio *dst, struct bio *src);
 489#else   /* CONFIG_BLK_CGROUP */
 490static inline int bio_associate_blkcg(struct bio *bio,
 491                        struct cgroup_subsys_state *blkcg_css) { return 0; }
 492static inline int bio_associate_current(struct bio *bio) { return -ENOENT; }
 493static inline void bio_disassociate_task(struct bio *bio) { }
 494static inline void bio_clone_blkcg_association(struct bio *dst,
 495                        struct bio *src) { }
 496#endif  /* CONFIG_BLK_CGROUP */
 497
 498#ifdef CONFIG_HIGHMEM
 499/*
 500 * remember never ever reenable interrupts between a bvec_kmap_irq and
 501 * bvec_kunmap_irq!
 502 */
 503static inline char *bvec_kmap_irq(struct bio_vec *bvec, unsigned long *flags)
 504{
 505        unsigned long addr;
 506
 507        /*
 508         * might not be a highmem page, but the preempt/irq count
 509         * balancing is a lot nicer this way
 510         */
 511        local_irq_save(*flags);
 512        addr = (unsigned long) kmap_atomic(bvec->bv_page);
 513
 514        BUG_ON(addr & ~PAGE_MASK);
 515
 516        return (char *) addr + bvec->bv_offset;
 517}
 518
 519static inline void bvec_kunmap_irq(char *buffer, unsigned long *flags)
 520{
 521        unsigned long ptr = (unsigned long) buffer & PAGE_MASK;
 522
 523        kunmap_atomic((void *) ptr);
 524        local_irq_restore(*flags);
 525}
 526
 527#else
 528static inline char *bvec_kmap_irq(struct bio_vec *bvec, unsigned long *flags)
 529{
 530        return page_address(bvec->bv_page) + bvec->bv_offset;
 531}
 532
 533static inline void bvec_kunmap_irq(char *buffer, unsigned long *flags)
 534{
 535        *flags = 0;
 536}
 537#endif
 538
 539static inline char *__bio_kmap_irq(struct bio *bio, struct bvec_iter iter,
 540                                   unsigned long *flags)
 541{
 542        return bvec_kmap_irq(&bio_iter_iovec(bio, iter), flags);
 543}
 544#define __bio_kunmap_irq(buf, flags)    bvec_kunmap_irq(buf, flags)
 545
 546#define bio_kmap_irq(bio, flags) \
 547        __bio_kmap_irq((bio), (bio)->bi_iter, (flags))
 548#define bio_kunmap_irq(buf,flags)       __bio_kunmap_irq(buf, flags)
 549
 550/*
 551 * BIO list management for use by remapping drivers (e.g. DM or MD) and loop.
 552 *
 553 * A bio_list anchors a singly-linked list of bios chained through the bi_next
 554 * member of the bio.  The bio_list also caches the last list member to allow
 555 * fast access to the tail.
 556 */
 557struct bio_list {
 558        struct bio *head;
 559        struct bio *tail;
 560};
 561
 562static inline int bio_list_empty(const struct bio_list *bl)
 563{
 564        return bl->head == NULL;
 565}
 566
 567static inline void bio_list_init(struct bio_list *bl)
 568{
 569        bl->head = bl->tail = NULL;
 570}
 571
 572#define BIO_EMPTY_LIST  { NULL, NULL }
 573
 574#define bio_list_for_each(bio, bl) \
 575        for (bio = (bl)->head; bio; bio = bio->bi_next)
 576
 577static inline unsigned bio_list_size(const struct bio_list *bl)
 578{
 579        unsigned sz = 0;
 580        struct bio *bio;
 581
 582        bio_list_for_each(bio, bl)
 583                sz++;
 584
 585        return sz;
 586}
 587
 588static inline void bio_list_add(struct bio_list *bl, struct bio *bio)
 589{
 590        bio->bi_next = NULL;
 591
 592        if (bl->tail)
 593                bl->tail->bi_next = bio;
 594        else
 595                bl->head = bio;
 596
 597        bl->tail = bio;
 598}
 599
 600static inline void bio_list_add_head(struct bio_list *bl, struct bio *bio)
 601{
 602        bio->bi_next = bl->head;
 603
 604        bl->head = bio;
 605
 606        if (!bl->tail)
 607                bl->tail = bio;
 608}
 609
 610static inline void bio_list_merge(struct bio_list *bl, struct bio_list *bl2)
 611{
 612        if (!bl2->head)
 613                return;
 614
 615        if (bl->tail)
 616                bl->tail->bi_next = bl2->head;
 617        else
 618                bl->head = bl2->head;
 619
 620        bl->tail = bl2->tail;
 621}
 622
 623static inline void bio_list_merge_head(struct bio_list *bl,
 624                                       struct bio_list *bl2)
 625{
 626        if (!bl2->head)
 627                return;
 628
 629        if (bl->head)
 630                bl2->tail->bi_next = bl->head;
 631        else
 632                bl->tail = bl2->tail;
 633
 634        bl->head = bl2->head;
 635}
 636
 637static inline struct bio *bio_list_peek(struct bio_list *bl)
 638{
 639        return bl->head;
 640}
 641
 642static inline struct bio *bio_list_pop(struct bio_list *bl)
 643{
 644        struct bio *bio = bl->head;
 645
 646        if (bio) {
 647                bl->head = bl->head->bi_next;
 648                if (!bl->head)
 649                        bl->tail = NULL;
 650
 651                bio->bi_next = NULL;
 652        }
 653
 654        return bio;
 655}
 656
 657static inline struct bio *bio_list_get(struct bio_list *bl)
 658{
 659        struct bio *bio = bl->head;
 660
 661        bl->head = bl->tail = NULL;
 662
 663        return bio;
 664}
 665
 666/*
 667 * Increment chain count for the bio. Make sure the CHAIN flag update
 668 * is visible before the raised count.
 669 */
 670static inline void bio_inc_remaining(struct bio *bio)
 671{
 672        bio_set_flag(bio, BIO_CHAIN);
 673        smp_mb__before_atomic();
 674        atomic_inc(&bio->__bi_remaining);
 675}
 676
 677/*
 678 * bio_set is used to allow other portions of the IO system to
 679 * allocate their own private memory pools for bio and iovec structures.
 680 * These memory pools in turn all allocate from the bio_slab
 681 * and the bvec_slabs[].
 682 */
 683#define BIO_POOL_SIZE 2
 684
 685struct bio_set {
 686        struct kmem_cache *bio_slab;
 687        unsigned int front_pad;
 688
 689        mempool_t *bio_pool;
 690        mempool_t *bvec_pool;
 691#if defined(CONFIG_BLK_DEV_INTEGRITY)
 692        mempool_t *bio_integrity_pool;
 693        mempool_t *bvec_integrity_pool;
 694#endif
 695
 696        /*
 697         * Deadlock avoidance for stacking block drivers: see comments in
 698         * bio_alloc_bioset() for details
 699         */
 700        spinlock_t              rescue_lock;
 701        struct bio_list         rescue_list;
 702        struct work_struct      rescue_work;
 703        struct workqueue_struct *rescue_workqueue;
 704};
 705
 706struct biovec_slab {
 707        int nr_vecs;
 708        char *name;
 709        struct kmem_cache *slab;
 710};
 711
 712/*
 713 * a small number of entries is fine, not going to be performance critical.
 714 * basically we just need to survive
 715 */
 716#define BIO_SPLIT_ENTRIES 2
 717
 718#if defined(CONFIG_BLK_DEV_INTEGRITY)
 719
 720#define bip_for_each_vec(bvl, bip, iter)                                \
 721        for_each_bvec(bvl, (bip)->bip_vec, iter, (bip)->bip_iter)
 722
 723#define bio_for_each_integrity_vec(_bvl, _bio, _iter)                   \
 724        for_each_bio(_bio)                                              \
 725                bip_for_each_vec(_bvl, _bio->bi_integrity, _iter)
 726
 727extern struct bio_integrity_payload *bio_integrity_alloc(struct bio *, gfp_t, unsigned int);
 728extern void bio_integrity_free(struct bio *);
 729extern int bio_integrity_add_page(struct bio *, struct page *, unsigned int, unsigned int);
 730extern bool bio_integrity_enabled(struct bio *bio);
 731extern int bio_integrity_prep(struct bio *);
 732extern void bio_integrity_endio(struct bio *);
 733extern void bio_integrity_advance(struct bio *, unsigned int);
 734extern void bio_integrity_trim(struct bio *, unsigned int, unsigned int);
 735extern int bio_integrity_clone(struct bio *, struct bio *, gfp_t);
 736extern int bioset_integrity_create(struct bio_set *, int);
 737extern void bioset_integrity_free(struct bio_set *);
 738extern void bio_integrity_init(void);
 739
 740#else /* CONFIG_BLK_DEV_INTEGRITY */
 741
 742static inline void *bio_integrity(struct bio *bio)
 743{
 744        return NULL;
 745}
 746
 747static inline bool bio_integrity_enabled(struct bio *bio)
 748{
 749        return false;
 750}
 751
 752static inline int bioset_integrity_create(struct bio_set *bs, int pool_size)
 753{
 754        return 0;
 755}
 756
 757static inline void bioset_integrity_free (struct bio_set *bs)
 758{
 759        return;
 760}
 761
 762static inline int bio_integrity_prep(struct bio *bio)
 763{
 764        return 0;
 765}
 766
 767static inline void bio_integrity_free(struct bio *bio)
 768{
 769        return;
 770}
 771
 772static inline int bio_integrity_clone(struct bio *bio, struct bio *bio_src,
 773                                      gfp_t gfp_mask)
 774{
 775        return 0;
 776}
 777
 778static inline void bio_integrity_advance(struct bio *bio,
 779                                         unsigned int bytes_done)
 780{
 781        return;
 782}
 783
 784static inline void bio_integrity_trim(struct bio *bio, unsigned int offset,
 785                                      unsigned int sectors)
 786{
 787        return;
 788}
 789
 790static inline void bio_integrity_init(void)
 791{
 792        return;
 793}
 794
 795static inline bool bio_integrity_flagged(struct bio *bio, enum bip_flags flag)
 796{
 797        return false;
 798}
 799
 800static inline void *bio_integrity_alloc(struct bio * bio, gfp_t gfp,
 801                                                                unsigned int nr)
 802{
 803        return ERR_PTR(-EINVAL);
 804}
 805
 806static inline int bio_integrity_add_page(struct bio *bio, struct page *page,
 807                                        unsigned int len, unsigned int offset)
 808{
 809        return 0;
 810}
 811
 812#endif /* CONFIG_BLK_DEV_INTEGRITY */
 813
 814#endif /* CONFIG_BLOCK */
 815#endif /* __LINUX_BIO_H */
 816