include/linux/bio.h

   1 /*
   2  * 2.5 block I/O model
   3  *
   4  * Copyright (C) 2001 Jens Axboe <axboe@suse.de>
   5  *
   6  * This program is free software; you can redistribute it and/or modify
   7  * it under the terms of the GNU General Public License version 2 as
   8  * published by the Free Software Foundation.
   9  *
  10  * This program is distributed in the hope that it will be useful,
  11  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  12
  13  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  14  * GNU General Public License for more details.
  15  *
  16  * You should have received a copy of the GNU General Public Licens
  17  * along with this program; if not, write to the Free Software
  18  * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-
  19  */
  20 #ifndef __LINUX_BIO_H
  21 #define __LINUX_BIO_H
  22
  23 #include <linux/highmem.h>
  24 #include <linux/mempool.h>
  25 #include <linux/ioprio.h>
  26
  27 #ifdef CONFIG_BLOCK
  28
  29 #include <asm/io.h>
  30
  31 #define BIO_DEBUG
  32
  33 #ifdef BIO_DEBUG
  34 #define BIO_BUG_ON      BUG_ON
  35 #else
  36 #define BIO_BUG_ON
  37 #endif
  38
  39 #define BIO_MAX_PAGES           256
  40 #define BIO_MAX_SIZE            (BIO_MAX_PAGES << PAGE_CACHE_SHIFT)
  41 #define BIO_MAX_SECTORS         (BIO_MAX_SIZE >> 9)
  42
  43 /*
  44  * was unsigned short, but we might as well be ready for > 64kB I/O pages
  45  */
  46 struct bio_vec {
  47         struct page     *bv_page;
  48         unsigned int    bv_len;
  49         unsigned int    bv_offset;
  50 };
  51
  52 struct bio_set;
  53 struct bio;
  54 struct bio_integrity_payload;
  55 typedef void (bio_end_io_t) (struct bio *, int);
  56 typedef void (bio_destructor_t) (struct bio *);
  57
  58 /*
  59  * main unit of I/O for the block layer and lower layers (ie drivers and
  60  * stacking drivers)
  61  */
  62 struct bio {
  63         sector_t                bi_sector;      /* device address in 512 byte
  64                                                    sectors */
  65         struct bio              *bi_next;       /* request queue link */
  66         struct block_device     *bi_bdev;
  67         unsigned long           bi_flags;       /* status, command, etc */
  68         unsigned long           bi_rw;          /* bottom bits READ/WRITE,
  69                                                  * top bits priority
  70                                                  */
  71
  72         unsigned short          bi_vcnt;        /* how many bio_vec's */
  73         unsigned short          bi_idx;         /* current index into bvl_vec */
  74
  75         /* Number of segments in this BIO after
  76          * physical address coalescing is performed.
  77          */
  78         unsigned int            bi_phys_segments;
  79
  80         unsigned int            bi_size;        /* residual I/O count */
  81
  82         /*
  83          * To keep track of the max segment size, we account for the
  84          * sizes of the first and last mergeable segments in this bio.
  85          */
  86         unsigned int            bi_seg_front_size;
  87         unsigned int            bi_seg_back_size;
  88
  89         unsigned int            bi_max_vecs;    /* max bvl_vecs we can hold */
  90
  91         unsigned int            bi_comp_cpu;    /* completion CPU */
  92
  93         atomic_t                bi_cnt;         /* pin count */
  94
  95         struct bio_vec          *bi_io_vec;     /* the actual vec list */
  96
  97         bio_end_io_t            *bi_end_io;
  98
  99         void                    *bi_private;
 100 #if defined(CONFIG_BLK_DEV_INTEGRITY)
 101         struct bio_integrity_payload *bi_integrity;  /* data integrity */
 102 #endif
 103
 104         bio_destructor_t        *bi_destructor; /* destructor */
 105
 106         /*
 107          * We can inline a number of vecs at the end of the bio, to avoid
 108          * double allocations for a small number of bio_vecs. This member
 109          * MUST obviously be kept at the very end of the bio.
 110          */
 111         struct bio_vec          bi_inline_vecs[0];
 112 };
 113
 114 /*
 115  * bio flags
 116  */
 117 #define BIO_UPTODATE    0       /* ok after I/O completion */
 118 #define BIO_RW_BLOCK    1       /* RW_AHEAD set, and read/write would block */
 119 #define BIO_EOF         2       /* out-out-bounds error */
 120 #define BIO_SEG_VALID   3       /* bi_phys_segments valid */
 121 #define BIO_CLONED      4       /* doesn't own data */
 122 #define BIO_BOUNCED     5       /* bio is a bounce bio */
 123 #define BIO_USER_MAPPED 6       /* contains user pages */
 124 #define BIO_EOPNOTSUPP  7       /* not supported */
 125 #define BIO_CPU_AFFINE  8       /* complete bio on same CPU as submitted */
 126 #define BIO_NULL_MAPPED 9       /* contains invalid user pages */
 127 #define BIO_FS_INTEGRITY 10     /* fs owns integrity data, not block layer */
 128 #define BIO_QUIET       11      /* Make BIO Quiet */
 129 #define bio_flagged(bio, flag)  ((bio)->bi_flags & (1 << (flag)))
 130
 131 /*
 132  * top 4 bits of bio flags indicate the pool this bio came from
 133  */
 134 #define BIO_POOL_BITS           (4)
 135 #define BIO_POOL_NONE           ((1UL << BIO_POOL_BITS) - 1)
 136 #define BIO_POOL_OFFSET         (BITS_PER_LONG - BIO_POOL_BITS)
 137 #define BIO_POOL_MASK           (1UL << BIO_POOL_OFFSET)
 138 #define BIO_POOL_IDX(bio)       ((bio)->bi_flags >> BIO_POOL_OFFSET)
 139
 140 /*
 141  * bio bi_rw flags
 142  *
 143  * bit 0 -- data direction
 144  *      If not set, bio is a read from device. If set, it's a write to device.
 145  * bit 1 -- fail fast device errors
 146  * bit 2 -- fail fast transport errors
 147  * bit 3 -- fail fast driver errors
 148  * bit 4 -- rw-ahead when set
 149  * bit 5 -- barrier
 150  *      Insert a serialization point in the IO queue, forcing previously
 151  *      submitted IO to be completed before this one is issued.
 152  * bit 6 -- synchronous I/O hint.
 153  * bit 7 -- Unplug the device immediately after submitting this bio.
 154  * bit 8 -- metadata request
 155  *      Used for tracing to differentiate metadata and data IO. May also
 156  *      get some preferential treatment in the IO scheduler
 157  * bit 9 -- discard sectors
 158  *      Informs the lower level device that this range of sectors is no longer
 159  *      used by the file system and may thus be freed by the device. Used
 160  *      for flash based storage.
 161  *      Don't want driver retries for any fast fail whatever the reason.
 162  * bit 10 -- Tell the IO scheduler not to wait for more requests after this
 163         one has been submitted, even if it is a SYNC request.
 164  */
 165 enum bio_rw_flags {
 166         BIO_RW,
 167         BIO_RW_FAILFAST_DEV,
 168         BIO_RW_FAILFAST_TRANSPORT,
 169         BIO_RW_FAILFAST_DRIVER,
 170         /* above flags must match REQ_* */
 171         BIO_RW_AHEAD,
 172         BIO_RW_BARRIER,
 173         BIO_RW_SYNCIO,
 174         BIO_RW_UNPLUG,
 175         BIO_RW_META,
 176         BIO_RW_DISCARD,
 177         BIO_RW_NOIDLE,
 178 };
 179
 180 /*
 181  * First four bits must match between bio->bi_rw and rq->cmd_flags, make
 182  * that explicit here.
 183  */
 184 #define BIO_RW_RQ_MASK          0xf
 185
 186 static inline bool bio_rw_flagged(struct bio *bio, enum bio_rw_flags flag)
 187 {
 188         return (bio->bi_rw & (1 << flag)) != 0;
 189 }
 190
 191 /*
 192  * upper 16 bits of bi_rw define the io priority of this bio
 193  */
 194 #define BIO_PRIO_SHIFT  (8 * sizeof(unsigned long) - IOPRIO_BITS)
 195 #define bio_prio(bio)   ((bio)->bi_rw >> BIO_PRIO_SHIFT)
 196 #define bio_prio_valid(bio)     ioprio_valid(bio_prio(bio))
 197
 198 #define bio_set_prio(bio, prio)         do {                    \
 199         WARN_ON(prio >= (1 << IOPRIO_BITS));                    \
 200         (bio)->bi_rw &= ((1UL << BIO_PRIO_SHIFT) - 1);          \
 201         (bio)->bi_rw |= ((unsigned long) (prio) << BIO_PRIO_SHIFT);     \
 202 } while (0)
 203
 204 /*
 205  * various member access, note that bio_data should of course not be used
 206  * on highmem page vectors
 207  */
 208 #define bio_iovec_idx(bio, idx) (&((bio)->bi_io_vec[(idx)]))
 209 #define bio_iovec(bio)          bio_iovec_idx((bio), (bio)->bi_idx)
 210 #define bio_page(bio)           bio_iovec((bio))->bv_page
 211 #define bio_offset(bio)         bio_iovec((bio))->bv_offset
 212 #define bio_segments(bio)       ((bio)->bi_vcnt - (bio)->bi_idx)
 213 #define bio_sectors(bio)        ((bio)->bi_size >> 9)
 214 #define bio_empty_barrier(bio)  (bio_rw_flagged(bio, BIO_RW_BARRIER) && !bio_has_data(bio) && !bio_rw_flagged(bio, BIO_RW_DISCARD))
 215
 216 static inline unsigned int bio_cur_bytes(struct bio *bio)
 217 {
 218         if (bio->bi_vcnt)
 219                 return bio_iovec(bio)->bv_len;
 220         else /* dataless requests such as discard */
 221                 return bio->bi_size;
 222 }
 223
 224 static inline void *bio_data(struct bio *bio)
 225 {
 226         if (bio->bi_vcnt)
 227                 return page_address(bio_page(bio)) + bio_offset(bio);
 228
 229         return NULL;
 230 }
 231
 232 static inline int bio_has_allocated_vec(struct bio *bio)
 233 {
 234         return bio->bi_io_vec && bio->bi_io_vec != bio->bi_inline_vecs;
 235 }
 236
 237 /*
 238  * will die
 239  */
 240 #define bio_to_phys(bio)        (page_to_phys(bio_page((bio))) + (unsigned long) bio_offset((bio)))
 241 #define bvec_to_phys(bv)        (page_to_phys((bv)->bv_page) + (unsigned long) (bv)->bv_offset)
 242
 243 /*
 244  * queues that have highmem support enabled may still need to revert to
 245  * PIO transfers occasionally and thus map high pages temporarily. For
 246  * permanent PIO fall back, user is probably better off disabling highmem
 247  * I/O completely on that queue (see ide-dma for example)
 248  */
 249 #define __bio_kmap_atomic(bio, idx, kmtype)                             \
 250         (kmap_atomic(bio_iovec_idx((bio), (idx))->bv_page, kmtype) +    \
 251                 bio_iovec_idx((bio), (idx))->bv_offset)
 252
 253 #define __bio_kunmap_atomic(addr, kmtype) kunmap_atomic(addr, kmtype)
 254
 255 /*
 256  * merge helpers etc
 257  */
 258
 259 #define __BVEC_END(bio)         bio_iovec_idx((bio), (bio)->bi_vcnt - 1)
 260 #define __BVEC_START(bio)       bio_iovec_idx((bio), (bio)->bi_idx)
 261
 262 /* Default implementation of BIOVEC_PHYS_MERGEABLE */
 263 #define __BIOVEC_PHYS_MERGEABLE(vec1, vec2)     \
 264         ((bvec_to_phys((vec1)) + (vec1)->bv_len) == bvec_to_phys((vec2)))
 265
 266 /*
 267  * allow arch override, for eg virtualized architectures (put in asm/io.h)
 268  */
 269 #ifndef BIOVEC_PHYS_MERGEABLE
 270 #define BIOVEC_PHYS_MERGEABLE(vec1, vec2)       \
 271         __BIOVEC_PHYS_MERGEABLE(vec1, vec2)
 272 #endif
 273
 274 #define __BIO_SEG_BOUNDARY(addr1, addr2, mask) \
 275         (((addr1) | (mask)) == (((addr2) - 1) | (mask)))
 276 #define BIOVEC_SEG_BOUNDARY(q, b1, b2) \
 277         __BIO_SEG_BOUNDARY(bvec_to_phys((b1)), bvec_to_phys((b2)) + (b2)->bv_len, queue_segment_boundary((q)))
 278 #define BIO_SEG_BOUNDARY(q, b1, b2) \
 279         BIOVEC_SEG_BOUNDARY((q), __BVEC_END((b1)), __BVEC_START((b2)))
 280
 281 #define bio_io_error(bio) bio_endio((bio), -EIO)
 282
 283 /*
 284  * drivers should not use the __ version unless they _really_ want to
 285  * run through the entire bio and not just pending pieces
 286  */
 287 #define __bio_for_each_segment(bvl, bio, i, start_idx)                  \
 288         for (bvl = bio_iovec_idx((bio), (start_idx)), i = (start_idx);  \
 289              i < (bio)->bi_vcnt;                                        \
 290              bvl++, i++)
 291
 292 #define bio_for_each_segment(bvl, bio, i)                               \
 293         __bio_for_each_segment(bvl, bio, i, (bio)->bi_idx)
 294
 295 /*
 296  * get a reference to a bio, so it won't disappear. the intended use is
 297  * something like:
 298  *
 299  * bio_get(bio);
 300  * submit_bio(rw, bio);
 301  * if (bio->bi_flags ...)
 302  *      do_something
 303  * bio_put(bio);
 304  *
 305  * without the bio_get(), it could potentially complete I/O before submit_bio
 306  * returns. and then bio would be freed memory when if (bio->bi_flags ...)
 307  * runs
 308  */
 309 #define bio_get(bio)    atomic_inc(&(bio)->bi_cnt)
 310
 311 #if defined(CONFIG_BLK_DEV_INTEGRITY)
 312 /*
 313  * bio integrity payload
 314  */
 315 struct bio_integrity_payload {
 316         struct bio              *bip_bio;       /* parent bio */
 317
 318         sector_t                bip_sector;     /* virtual start sector */
 319
 320         void                    *bip_buf;       /* generated integrity data */
 321         bio_end_io_t            *bip_end_io;    /* saved I/O completion fn */
 322
 323         unsigned int            bip_size;
 324
 325         unsigned short          bip_slab;       /* slab the bip came from */
 326         unsigned short          bip_vcnt;       /* # of integrity bio_vecs */
 327         unsigned short          bip_idx;        /* current bip_vec index */
 328
 329         struct work_struct      bip_work;       /* I/O completion */
 330         struct bio_vec          bip_vec[0];     /* embedded bvec array */
 331 };
 332 #endif /* CONFIG_BLK_DEV_INTEGRITY */
 333
 334 /*
 335  * A bio_pair is used when we need to split a bio.
 336  * This can only happen for a bio that refers to just one
 337  * page of data, and in the unusual situation when the
 338  * page crosses a chunk/device boundary
 339  *
 340  * The address of the master bio is stored in bio1.bi_private
 341  * The address of the pool the pair was allocated from is stored
 342  *   in bio2.bi_private
 343  */
 344 struct bio_pair {
 345         struct bio                      bio1, bio2;
 346         struct bio_vec                  bv1, bv2;
 347 #if defined(CONFIG_BLK_DEV_INTEGRITY)
 348         struct bio_integrity_payload    bip1, bip2;
 349         struct bio_vec                  iv1, iv2;
 350 #endif
 351         atomic_t                        cnt;
 352         int                             error;
 353 };
 354 extern struct bio_pair *bio_split(struct bio *bi, int first_sectors);
 355 extern void bio_pair_release(struct bio_pair *dbio);
 356
 357 extern struct bio_set *bioset_create(unsigned int, unsigned int);
 358 extern void bioset_free(struct bio_set *);
 359
 360 extern struct bio *bio_alloc(gfp_t, int);
 361 extern struct bio *bio_kmalloc(gfp_t, int);
 362 extern struct bio *bio_alloc_bioset(gfp_t, int, struct bio_set *);
 363 extern void bio_put(struct bio *);
 364 extern void bio_free(struct bio *, struct bio_set *);
 365
 366 extern void bio_endio(struct bio *, int);
 367 struct request_queue;
 368 extern int bio_phys_segments(struct request_queue *, struct bio *);
 369
 370 extern void __bio_clone(struct bio *, struct bio *);
 371 extern struct bio *bio_clone(struct bio *, gfp_t);
 372
 373 extern void bio_init(struct bio *);
 374
 375 extern int bio_add_page(struct bio *, struct page *, unsigned int,unsigned int);
 376 extern int bio_add_pc_page(struct request_queue *, struct bio *, struct page *,
 377                            unsigned int, unsigned int);
 378 extern int bio_get_nr_vecs(struct block_device *);
 379 extern sector_t bio_sector_offset(struct bio *, unsigned short, unsigned int);
 380 extern struct bio *bio_map_user(struct request_queue *, struct block_device *,
 381                                 unsigned long, unsigned int, int, gfp_t);
 382 struct sg_iovec;
 383 struct rq_map_data;
 384 extern struct bio *bio_map_user_iov(struct request_queue *,
 385                                     struct block_device *,
 386                                     struct sg_iovec *, int, int, gfp_t);
 387 extern void bio_unmap_user(struct bio *);
 388 extern struct bio *bio_map_kern(struct request_queue *, void *, unsigned int,
 389                                 gfp_t);
 390 extern struct bio *bio_copy_kern(struct request_queue *, void *, unsigned int,
 391                                  gfp_t, int);
 392 extern void bio_set_pages_dirty(struct bio *bio);
 393 extern void bio_check_pages_dirty(struct bio *bio);
 394 extern struct bio *bio_copy_user(struct request_queue *, struct rq_map_data *,
 395                                  unsigned long, unsigned int, int, gfp_t);
 396 extern struct bio *bio_copy_user_iov(struct request_queue *,
 397                                      struct rq_map_data *, struct sg_iovec *,
 398                                      int, int, gfp_t);
 399 extern int bio_uncopy_user(struct bio *);
 400 void zero_fill_bio(struct bio *bio);
 401 extern struct bio_vec *bvec_alloc_bs(gfp_t, int, unsigned long *, struct bio_set *);
 402 extern void bvec_free_bs(struct bio_set *, struct bio_vec *, unsigned int);
 403 extern unsigned int bvec_nr_vecs(unsigned short idx);
 404
 405 /*
 406  * Allow queuer to specify a completion CPU for this bio
 407  */
 408 static inline void bio_set_completion_cpu(struct bio *bio, unsigned int cpu)
 409 {
 410         bio->bi_comp_cpu = cpu;
 411 }
 412
 413 /*
 414  * bio_set is used to allow other portions of the IO system to
 415  * allocate their own private memory pools for bio and iovec structures.
 416  * These memory pools in turn all allocate from the bio_slab
 417  * and the bvec_slabs[].
 418  */
 419 #define BIO_POOL_SIZE 2
 420 #define BIOVEC_NR_POOLS 6
 421 #define BIOVEC_MAX_IDX  (BIOVEC_NR_POOLS - 1)
 422
 423 struct bio_set {
 424         struct kmem_cache *bio_slab;
 425         unsigned int front_pad;
 426
 427         mempool_t *bio_pool;
 428 #if defined(CONFIG_BLK_DEV_INTEGRITY)
 429         mempool_t *bio_integrity_pool;
 430 #endif
 431         mempool_t *bvec_pool;
 432 };
 433
 434 struct biovec_slab {
 435         int nr_vecs;
 436         char *name;
 437         struct kmem_cache *slab;
 438 };
 439
 440 extern struct bio_set *fs_bio_set;
 441 extern struct biovec_slab bvec_slabs[BIOVEC_NR_POOLS] __read_mostly;
 442
 443 /*
 444  * a small number of entries is fine, not going to be performance critical.
 445  * basically we just need to survive
 446  */
 447 #define BIO_SPLIT_ENTRIES 2
 448
 449 #ifdef CONFIG_HIGHMEM
 450 /*
 451  * remember never ever reenable interrupts between a bvec_kmap_irq and
 452  * bvec_kunmap_irq!
 453  */
 454 static inline char *bvec_kmap_irq(struct bio_vec *bvec, unsigned long *flags)
 455 {
 456         unsigned long addr;
 457
 458         /*
 459          * might not be a highmem page, but the preempt/irq count
 460          * balancing is a lot nicer this way
 461          */
 462         local_irq_save(*flags);
 463         addr = (unsigned long) kmap_atomic(bvec->bv_page, KM_BIO_SRC_IRQ);
 464
 465         BUG_ON(addr & ~PAGE_MASK);
 466
 467         return (char *) addr + bvec->bv_offset;
 468 }
 469
 470 static inline void bvec_kunmap_irq(char *buffer, unsigned long *flags)
 471 {
 472         unsigned long ptr = (unsigned long) buffer & PAGE_MASK;
 473
 474         kunmap_atomic((void *) ptr, KM_BIO_SRC_IRQ);
 475         local_irq_restore(*flags);
 476 }
 477
 478 #else
 479 #define bvec_kmap_irq(bvec, flags)      (page_address((bvec)->bv_page) + (bvec)->bv_offset)
 480 #define bvec_kunmap_irq(buf, flags)     do { *(flags) = 0; } while (0)
 481 #endif
 482
 483 static inline char *__bio_kmap_irq(struct bio *bio, unsigned short idx,
 484                                    unsigned long *flags)
 485 {
 486         return bvec_kmap_irq(bio_iovec_idx(bio, idx), flags);
 487 }
 488 #define __bio_kunmap_irq(buf, flags)    bvec_kunmap_irq(buf, flags)
 489
 490 #define bio_kmap_irq(bio, flags) \
 491         __bio_kmap_irq((bio), (bio)->bi_idx, (flags))
 492 #define bio_kunmap_irq(buf,flags)       __bio_kunmap_irq(buf, flags)
 493
 494 /*
 495  * Check whether this bio carries any data or not. A NULL bio is allowed.
 496  */
 497 static inline int bio_has_data(struct bio *bio)
 498 {
 499         return bio && bio->bi_io_vec != NULL;
 500 }
 501
 502 /*
 503  * BIO list management for use by remapping drivers (e.g. DM or MD) and loop.
 504  *
 505  * A bio_list anchors a singly-linked list of bios chained through the bi_next
 506  * member of the bio.  The bio_list also caches the last list member to allow
 507  * fast access to the tail.
 508  */
 509 struct bio_list {
 510         struct bio *head;
 511         struct bio *tail;
 512 };
 513
 514 static inline int bio_list_empty(const struct bio_list *bl)
 515 {
 516         return bl->head == NULL;
 517 }
 518
 519 static inline void bio_list_init(struct bio_list *bl)
 520 {
 521         bl->head = bl->tail = NULL;
 522 }
 523
 524 #define bio_list_for_each(bio, bl) \
 525         for (bio = (bl)->head; bio; bio = bio->bi_next)
 526
 527 static inline unsigned bio_list_size(const struct bio_list *bl)
 528 {
 529         unsigned sz = 0;
 530         struct bio *bio;
 531
 532         bio_list_for_each(bio, bl)
 533                 sz++;
 534
 535         return sz;
 536 }
 537
 538 static inline void bio_list_add(struct bio_list *bl, struct bio *bio)
 539 {
 540         bio->bi_next = NULL;
 541
 542         if (bl->tail)
 543                 bl->tail->bi_next = bio;
 544         else
 545                 bl->head = bio;
 546
 547         bl->tail = bio;
 548 }
 549
 550 static inline void bio_list_add_head(struct bio_list *bl, struct bio *bio)
 551 {
 552         bio->bi_next = bl->head;
 553
 554         bl->head = bio;
 555
 556         if (!bl->tail)
 557                 bl->tail = bio;
 558 }
 559
 560 static inline void bio_list_merge(struct bio_list *bl, struct bio_list *bl2)
 561 {
 562         if (!bl2->head)
 563                 return;
 564
 565         if (bl->tail)
 566                 bl->tail->bi_next = bl2->head;
 567         else
 568                 bl->head = bl2->head;
 569
 570         bl->tail = bl2->tail;
 571 }
 572
 573 static inline void bio_list_merge_head(struct bio_list *bl,
 574                                        struct bio_list *bl2)
 575 {
 576         if (!bl2->head)
 577                 return;
 578
 579         if (bl->head)
 580                 bl2->tail->bi_next = bl->head;
 581         else
 582                 bl->tail = bl2->tail;
 583
 584         bl->head = bl2->head;
 585 }
 586
 587 static inline struct bio *bio_list_peek(struct bio_list *bl)
 588 {
 589         return bl->head;
 590 }
 591
 592 static inline struct bio *bio_list_pop(struct bio_list *bl)
 593 {
 594         struct bio *bio = bl->head;
 595
 596         if (bio) {
 597                 bl->head = bl->head->bi_next;
 598                 if (!bl->head)
 599                         bl->tail = NULL;
 600
 601                 bio->bi_next = NULL;
 602         }
 603
 604         return bio;
 605 }
 606
 607 static inline struct bio *bio_list_get(struct bio_list *bl)
 608 {
 609         struct bio *bio = bl->head;
 610
 611         bl->head = bl->tail = NULL;
 612
 613         return bio;
 614 }
 615
 616 #if defined(CONFIG_BLK_DEV_INTEGRITY)
 617
 618 #define bip_vec_idx(bip, idx)   (&(bip->bip_vec[(idx)]))
 619 #define bip_vec(bip)            bip_vec_idx(bip, 0)
 620
 621 #define __bip_for_each_vec(bvl, bip, i, start_idx)                      \
 622         for (bvl = bip_vec_idx((bip), (start_idx)), i = (start_idx);    \
 623              i < (bip)->bip_vcnt;                                       \
 624              bvl++, i++)
 625
 626 #define bip_for_each_vec(bvl, bip, i)                                   \
 627         __bip_for_each_vec(bvl, bip, i, (bip)->bip_idx)
 628
 629 #define bio_integrity(bio) (bio->bi_integrity != NULL)
 630
 631 extern struct bio_integrity_payload *bio_integrity_alloc_bioset(struct bio *, gfp_t, unsigned int, struct bio_set *);
 632 extern struct bio_integrity_payload *bio_integrity_alloc(struct bio *, gfp_t, unsigned int);
 633 extern void bio_integrity_free(struct bio *, struct bio_set *);
 634 extern int bio_integrity_add_page(struct bio *, struct page *, unsigned int, unsigned int);
 635 extern int bio_integrity_enabled(struct bio *bio);
 636 extern int bio_integrity_set_tag(struct bio *, void *, unsigned int);
 637 extern int bio_integrity_get_tag(struct bio *, void *, unsigned int);
 638 extern int bio_integrity_prep(struct bio *);
 639 extern void bio_integrity_endio(struct bio *, int);
 640 extern void bio_integrity_advance(struct bio *, unsigned int);
 641 extern void bio_integrity_trim(struct bio *, unsigned int, unsigned int);
 642 extern void bio_integrity_split(struct bio *, struct bio_pair *, int);
 643 extern int bio_integrity_clone(struct bio *, struct bio *, gfp_t, struct bio_set *);
 644 extern int bioset_integrity_create(struct bio_set *, int);
 645 extern void bioset_integrity_free(struct bio_set *);
 646 extern void bio_integrity_init(void);
 647
 648 #else /* CONFIG_BLK_DEV_INTEGRITY */
 649
 650 #define bio_integrity(a)                (0)
 651 #define bioset_integrity_create(a, b)   (0)
 652 #define bio_integrity_prep(a)           (0)
 653 #define bio_integrity_enabled(a)        (0)
 654 #define bio_integrity_clone(a, b, c, d) (0)
 655 #define bioset_integrity_free(a)        do { } while (0)
 656 #define bio_integrity_free(a, b)        do { } while (0)
 657 #define bio_integrity_endio(a, b)       do { } while (0)
 658 #define bio_integrity_advance(a, b)     do { } while (0)
 659 #define bio_integrity_trim(a, b, c)     do { } while (0)
 660 #define bio_integrity_split(a, b, c)    do { } while (0)
 661 #define bio_integrity_set_tag(a, b, c)  do { } while (0)
 662 #define bio_integrity_get_tag(a, b, c)  do { } while (0)
 663 #define bio_integrity_init(a)           do { } while (0)
 664
 665 #endif /* CONFIG_BLK_DEV_INTEGRITY */
 666
 667 #endif /* CONFIG_BLOCK */
 668 #endif /* __LINUX_BIO_H */