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_OFFSET         (BITS_PER_LONG - BIO_POOL_BITS)
 136 #define BIO_POOL_MASK           (1UL << BIO_POOL_OFFSET)
 137 #define BIO_POOL_IDX(bio)       ((bio)->bi_flags >> BIO_POOL_OFFSET)
 138
 139 /*
 140  * bio bi_rw flags
 141  *
 142  * bit 0 -- data direction
 143  *      If not set, bio is a read from device. If set, it's a write to device.
 144  * bit 1 -- rw-ahead when set
 145  * bit 2 -- barrier
 146  *      Insert a serialization point in the IO queue, forcing previously
 147  *      submitted IO to be completed before this one is issued.
 148  * bit 3 -- synchronous I/O hint.
 149  * bit 4 -- Unplug the device immediately after submitting this bio.
 150  * bit 5 -- metadata request
 151  *      Used for tracing to differentiate metadata and data IO. May also
 152  *      get some preferential treatment in the IO scheduler
 153  * bit 6 -- discard sectors
 154  *      Informs the lower level device that this range of sectors is no longer
 155  *      used by the file system and may thus be freed by the device. Used
 156  *      for flash based storage.
 157  * bit 7 -- fail fast device errors
 158  * bit 8 -- fail fast transport errors
 159  * bit 9 -- fail fast driver errors
 160  *      Don't want driver retries for any fast fail whatever the reason.
 161  * bit 10 -- Tell the IO scheduler not to wait for more requests after this
 162         one has been submitted, even if it is a SYNC request.
 163  */
 164 #define BIO_RW          0       /* Must match RW in req flags (blkdev.h) */
 165 #define BIO_RW_AHEAD    1       /* Must match FAILFAST in req flags */
 166 #define BIO_RW_BARRIER  2
 167 #define BIO_RW_SYNCIO   3
 168 #define BIO_RW_UNPLUG   4
 169 #define BIO_RW_META     5
 170 #define BIO_RW_DISCARD  6
 171 #define BIO_RW_FAILFAST_DEV             7
 172 #define BIO_RW_FAILFAST_TRANSPORT       8
 173 #define BIO_RW_FAILFAST_DRIVER          9
 174 #define BIO_RW_NOIDLE   10
 175
 176 #define bio_rw_flagged(bio, flag)       ((bio)->bi_rw & (1 << (flag)))
 177
 178 /*
 179  * Old defines, these should eventually be replaced by direct usage of
 180  * bio_rw_flagged()
 181  */
 182 #define bio_barrier(bio)        bio_rw_flagged(bio, BIO_RW_BARRIER)
 183 #define bio_sync(bio)           bio_rw_flagged(bio, BIO_RW_SYNCIO)
 184 #define bio_unplug(bio)         bio_rw_flagged(bio, BIO_RW_UNPLUG)
 185 #define bio_failfast_dev(bio)   bio_rw_flagged(bio, BIO_RW_FAILFAST_DEV)
 186 #define bio_failfast_transport(bio)     \
 187                 bio_rw_flagged(bio, BIO_RW_FAILFAST_TRANSPORT)
 188 #define bio_failfast_driver(bio)        \
 189                 bio_rw_flagged(bio, BIO_RW_FAILFAST_DRIVER)
 190 #define bio_rw_ahead(bio)       bio_rw_flagged(bio, BIO_RW_AHEAD)
 191 #define bio_rw_meta(bio)        bio_rw_flagged(bio, BIO_RW_META)
 192 #define bio_discard(bio)        bio_rw_flagged(bio, BIO_RW_DISCARD)
 193 #define bio_noidle(bio)         bio_rw_flagged(bio, BIO_RW_NOIDLE)
 194
 195 /*
 196  * upper 16 bits of bi_rw define the io priority of this bio
 197  */
 198 #define BIO_PRIO_SHIFT  (8 * sizeof(unsigned long) - IOPRIO_BITS)
 199 #define bio_prio(bio)   ((bio)->bi_rw >> BIO_PRIO_SHIFT)
 200 #define bio_prio_valid(bio)     ioprio_valid(bio_prio(bio))
 201
 202 #define bio_set_prio(bio, prio)         do {                    \
 203         WARN_ON(prio >= (1 << IOPRIO_BITS));                    \
 204         (bio)->bi_rw &= ((1UL << BIO_PRIO_SHIFT) - 1);          \
 205         (bio)->bi_rw |= ((unsigned long) (prio) << BIO_PRIO_SHIFT);     \
 206 } while (0)
 207
 208 /*
 209  * various member access, note that bio_data should of course not be used
 210  * on highmem page vectors
 211  */
 212 #define bio_iovec_idx(bio, idx) (&((bio)->bi_io_vec[(idx)]))
 213 #define bio_iovec(bio)          bio_iovec_idx((bio), (bio)->bi_idx)
 214 #define bio_page(bio)           bio_iovec((bio))->bv_page
 215 #define bio_offset(bio)         bio_iovec((bio))->bv_offset
 216 #define bio_segments(bio)       ((bio)->bi_vcnt - (bio)->bi_idx)
 217 #define bio_sectors(bio)        ((bio)->bi_size >> 9)
 218 #define bio_empty_barrier(bio)  (bio_barrier(bio) && !bio_has_data(bio) && !bio_discard(bio))
 219
 220 static inline unsigned int bio_cur_sectors(struct bio *bio)
 221 {
 222         if (bio->bi_vcnt)
 223                 return bio_iovec(bio)->bv_len >> 9;
 224         else /* dataless requests such as discard */
 225                 return bio->bi_size >> 9;
 226 }
 227
 228 static inline void *bio_data(struct bio *bio)
 229 {
 230         if (bio->bi_vcnt)
 231                 return page_address(bio_page(bio)) + bio_offset(bio);
 232
 233         return NULL;
 234 }
 235
 236 static inline int bio_has_allocated_vec(struct bio *bio)
 237 {
 238         return bio->bi_io_vec && bio->bi_io_vec != bio->bi_inline_vecs;
 239 }
 240
 241 /*
 242  * will die
 243  */
 244 #define bio_to_phys(bio)        (page_to_phys(bio_page((bio))) + (unsigned long) bio_offset((bio)))
 245 #define bvec_to_phys(bv)        (page_to_phys((bv)->bv_page) + (unsigned long) (bv)->bv_offset)
 246
 247 /*
 248  * queues that have highmem support enabled may still need to revert to
 249  * PIO transfers occasionally and thus map high pages temporarily. For
 250  * permanent PIO fall back, user is probably better off disabling highmem
 251  * I/O completely on that queue (see ide-dma for example)
 252  */
 253 #define __bio_kmap_atomic(bio, idx, kmtype)                             \
 254         (kmap_atomic(bio_iovec_idx((bio), (idx))->bv_page, kmtype) +    \
 255                 bio_iovec_idx((bio), (idx))->bv_offset)
 256
 257 #define __bio_kunmap_atomic(addr, kmtype) kunmap_atomic(addr, kmtype)
 258
 259 /*
 260  * merge helpers etc
 261  */
 262
 263 #define __BVEC_END(bio)         bio_iovec_idx((bio), (bio)->bi_vcnt - 1)
 264 #define __BVEC_START(bio)       bio_iovec_idx((bio), (bio)->bi_idx)
 265
 266 /* Default implementation of BIOVEC_PHYS_MERGEABLE */
 267 #define __BIOVEC_PHYS_MERGEABLE(vec1, vec2)     \
 268         ((bvec_to_phys((vec1)) + (vec1)->bv_len) == bvec_to_phys((vec2)))
 269
 270 /*
 271  * allow arch override, for eg virtualized architectures (put in asm/io.h)
 272  */
 273 #ifndef BIOVEC_PHYS_MERGEABLE
 274 #define BIOVEC_PHYS_MERGEABLE(vec1, vec2)       \
 275         __BIOVEC_PHYS_MERGEABLE(vec1, vec2)
 276 #endif
 277
 278 #define __BIO_SEG_BOUNDARY(addr1, addr2, mask) \
 279         (((addr1) | (mask)) == (((addr2) - 1) | (mask)))
 280 #define BIOVEC_SEG_BOUNDARY(q, b1, b2) \
 281         __BIO_SEG_BOUNDARY(bvec_to_phys((b1)), bvec_to_phys((b2)) + (b2)->bv_len, (q)->seg_boundary_mask)
 282 #define BIO_SEG_BOUNDARY(q, b1, b2) \
 283         BIOVEC_SEG_BOUNDARY((q), __BVEC_END((b1)), __BVEC_START((b2)))
 284
 285 #define bio_io_error(bio) bio_endio((bio), -EIO)
 286
 287 /*
 288  * drivers should not use the __ version unless they _really_ want to
 289  * run through the entire bio and not just pending pieces
 290  */
 291 #define __bio_for_each_segment(bvl, bio, i, start_idx)                  \
 292         for (bvl = bio_iovec_idx((bio), (start_idx)), i = (start_idx);  \
 293              i < (bio)->bi_vcnt;                                        \
 294              bvl++, i++)
 295
 296 #define bio_for_each_segment(bvl, bio, i)                               \
 297         __bio_for_each_segment(bvl, bio, i, (bio)->bi_idx)
 298
 299 /*
 300  * get a reference to a bio, so it won't disappear. the intended use is
 301  * something like:
 302  *
 303  * bio_get(bio);
 304  * submit_bio(rw, bio);
 305  * if (bio->bi_flags ...)
 306  *      do_something
 307  * bio_put(bio);
 308  *
 309  * without the bio_get(), it could potentially complete I/O before submit_bio
 310  * returns. and then bio would be freed memory when if (bio->bi_flags ...)
 311  * runs
 312  */
 313 #define bio_get(bio)    atomic_inc(&(bio)->bi_cnt)
 314
 315 #if defined(CONFIG_BLK_DEV_INTEGRITY)
 316 /*
 317  * bio integrity payload
 318  */
 319 struct bio_integrity_payload {
 320         struct bio              *bip_bio;       /* parent bio */
 321         struct bio_vec          *bip_vec;       /* integrity data vector */
 322
 323         sector_t                bip_sector;     /* virtual start sector */
 324
 325         void                    *bip_buf;       /* generated integrity data */
 326         bio_end_io_t            *bip_end_io;    /* saved I/O completion fn */
 327
 328         unsigned int            bip_size;
 329
 330         unsigned short          bip_pool;       /* pool the ivec came from */
 331         unsigned short          bip_vcnt;       /* # of integrity bio_vecs */
 332         unsigned short          bip_idx;        /* current bip_vec index */
 333
 334         struct work_struct      bip_work;       /* I/O completion */
 335 };
 336 #endif /* CONFIG_BLK_DEV_INTEGRITY */
 337
 338 /*
 339  * A bio_pair is used when we need to split a bio.
 340  * This can only happen for a bio that refers to just one
 341  * page of data, and in the unusual situation when the
 342  * page crosses a chunk/device boundary
 343  *
 344  * The address of the master bio is stored in bio1.bi_private
 345  * The address of the pool the pair was allocated from is stored
 346  *   in bio2.bi_private
 347  */
 348 struct bio_pair {
 349         struct bio                      bio1, bio2;
 350         struct bio_vec                  bv1, bv2;
 351 #if defined(CONFIG_BLK_DEV_INTEGRITY)
 352         struct bio_integrity_payload    bip1, bip2;
 353         struct bio_vec                  iv1, iv2;
 354 #endif
 355         atomic_t                        cnt;
 356         int                             error;
 357 };
 358 extern struct bio_pair *bio_split(struct bio *bi, int first_sectors);
 359 extern void bio_pair_release(struct bio_pair *dbio);
 360
 361 extern struct bio_set *bioset_create(unsigned int, unsigned int);
 362 extern void bioset_free(struct bio_set *);
 363
 364 extern struct bio *bio_alloc(gfp_t, int);
 365 extern struct bio *bio_kmalloc(gfp_t, int);
 366 extern struct bio *bio_alloc_bioset(gfp_t, int, struct bio_set *);
 367 extern void bio_put(struct bio *);
 368 extern void bio_free(struct bio *, struct bio_set *);
 369
 370 extern void bio_endio(struct bio *, int);
 371 struct request_queue;
 372 extern int bio_phys_segments(struct request_queue *, struct bio *);
 373
 374 extern void __bio_clone(struct bio *, struct bio *);
 375 extern struct bio *bio_clone(struct bio *, gfp_t);
 376
 377 extern void bio_init(struct bio *);
 378
 379 extern int bio_add_page(struct bio *, struct page *, unsigned int,unsigned int);
 380 extern int bio_add_pc_page(struct request_queue *, struct bio *, struct page *,
 381                            unsigned int, unsigned int);
 382 extern int bio_get_nr_vecs(struct block_device *);
 383 extern sector_t bio_sector_offset(struct bio *, unsigned short, unsigned int);
 384 extern struct bio *bio_map_user(struct request_queue *, struct block_device *,
 385                                 unsigned long, unsigned int, int, gfp_t);
 386 struct sg_iovec;
 387 struct rq_map_data;
 388 extern struct bio *bio_map_user_iov(struct request_queue *,
 389                                     struct block_device *,
 390                                     struct sg_iovec *, int, int, gfp_t);
 391 extern void bio_unmap_user(struct bio *);
 392 extern struct bio *bio_map_kern(struct request_queue *, void *, unsigned int,
 393                                 gfp_t);
 394 extern struct bio *bio_copy_kern(struct request_queue *, void *, unsigned int,
 395                                  gfp_t, int);
 396 extern void bio_set_pages_dirty(struct bio *bio);
 397 extern void bio_check_pages_dirty(struct bio *bio);
 398 extern struct bio *bio_copy_user(struct request_queue *, struct rq_map_data *,
 399                                  unsigned long, unsigned int, int, gfp_t);
 400 extern struct bio *bio_copy_user_iov(struct request_queue *,
 401                                      struct rq_map_data *, struct sg_iovec *,
 402                                      int, int, gfp_t);
 403 extern int bio_uncopy_user(struct bio *);
 404 void zero_fill_bio(struct bio *bio);
 405 extern struct bio_vec *bvec_alloc_bs(gfp_t, int, unsigned long *, struct bio_set *);
 406 extern void bvec_free_bs(struct bio_set *, struct bio_vec *, unsigned int);
 407 extern unsigned int bvec_nr_vecs(unsigned short idx);
 408
 409 /*
 410  * Allow queuer to specify a completion CPU for this bio
 411  */
 412 static inline void bio_set_completion_cpu(struct bio *bio, unsigned int cpu)
 413 {
 414         bio->bi_comp_cpu = cpu;
 415 }
 416
 417 /*
 418  * bio_set is used to allow other portions of the IO system to
 419  * allocate their own private memory pools for bio and iovec structures.
 420  * These memory pools in turn all allocate from the bio_slab
 421  * and the bvec_slabs[].
 422  */
 423 #define BIO_POOL_SIZE 2
 424 #define BIOVEC_NR_POOLS 6
 425 #define BIOVEC_MAX_IDX  (BIOVEC_NR_POOLS - 1)
 426
 427 struct bio_set {
 428         struct kmem_cache *bio_slab;
 429         unsigned int front_pad;
 430
 431         mempool_t *bio_pool;
 432         mempool_t *bvec_pool;
 433 };
 434
 435 struct biovec_slab {
 436         int nr_vecs;
 437         char *name;
 438         struct kmem_cache *slab;
 439 };
 440
 441 extern struct bio_set *fs_bio_set;
 442 extern struct biovec_slab bvec_slabs[BIOVEC_NR_POOLS] __read_mostly;
 443
 444 /*
 445  * a small number of entries is fine, not going to be performance critical.
 446  * basically we just need to survive
 447  */
 448 #define BIO_SPLIT_ENTRIES 2
 449
 450 #ifdef CONFIG_HIGHMEM
 451 /*
 452  * remember never ever reenable interrupts between a bvec_kmap_irq and
 453  * bvec_kunmap_irq!
 454  *
 455  * This function MUST be inlined - it plays with the CPU interrupt flags.
 456  */
 457 static __always_inline char *bvec_kmap_irq(struct bio_vec *bvec,
 458                 unsigned long *flags)
 459 {
 460         unsigned long addr;
 461
 462         /*
 463          * might not be a highmem page, but the preempt/irq count
 464          * balancing is a lot nicer this way
 465          */
 466         local_irq_save(*flags);
 467         addr = (unsigned long) kmap_atomic(bvec->bv_page, KM_BIO_SRC_IRQ);
 468
 469         BUG_ON(addr & ~PAGE_MASK);
 470
 471         return (char *) addr + bvec->bv_offset;
 472 }
 473
 474 static __always_inline void bvec_kunmap_irq(char *buffer,
 475                 unsigned long *flags)
 476 {
 477         unsigned long ptr = (unsigned long) buffer & PAGE_MASK;
 478
 479         kunmap_atomic((void *) ptr, KM_BIO_SRC_IRQ);
 480         local_irq_restore(*flags);
 481 }
 482
 483 #else
 484 #define bvec_kmap_irq(bvec, flags)      (page_address((bvec)->bv_page) + (bvec)->bv_offset)
 485 #define bvec_kunmap_irq(buf, flags)     do { *(flags) = 0; } while (0)
 486 #endif
 487
 488 static inline char *__bio_kmap_irq(struct bio *bio, unsigned short idx,
 489                                    unsigned long *flags)
 490 {
 491         return bvec_kmap_irq(bio_iovec_idx(bio, idx), flags);
 492 }
 493 #define __bio_kunmap_irq(buf, flags)    bvec_kunmap_irq(buf, flags)
 494
 495 #define bio_kmap_irq(bio, flags) \
 496         __bio_kmap_irq((bio), (bio)->bi_idx, (flags))
 497 #define bio_kunmap_irq(buf,flags)       __bio_kunmap_irq(buf, flags)
 498
 499 /*
 500  * Check whether this bio carries any data or not. A NULL bio is allowed.
 501  */
 502 static inline int bio_has_data(struct bio *bio)
 503 {
 504         return bio && bio->bi_io_vec != NULL;
 505 }
 506
 507 /*
 508  * BIO list managment for use by remapping drivers (e.g. DM or MD).
 509  *
 510  * A bio_list anchors a singly-linked list of bios chained through the bi_next
 511  * member of the bio.  The bio_list also caches the last list member to allow
 512  * fast access to the tail.
 513  */
 514 struct bio_list {
 515         struct bio *head;
 516         struct bio *tail;
 517 };
 518
 519 static inline int bio_list_empty(const struct bio_list *bl)
 520 {
 521         return bl->head == NULL;
 522 }
 523
 524 static inline void bio_list_init(struct bio_list *bl)
 525 {
 526         bl->head = bl->tail = NULL;
 527 }
 528
 529 #define bio_list_for_each(bio, bl) \
 530         for (bio = (bl)->head; bio; bio = bio->bi_next)
 531
 532 static inline unsigned bio_list_size(const struct bio_list *bl)
 533 {
 534         unsigned sz = 0;
 535         struct bio *bio;
 536
 537         bio_list_for_each(bio, bl)
 538                 sz++;
 539
 540         return sz;
 541 }
 542
 543 static inline void bio_list_add(struct bio_list *bl, struct bio *bio)
 544 {
 545         bio->bi_next = NULL;
 546
 547         if (bl->tail)
 548                 bl->tail->bi_next = bio;
 549         else
 550                 bl->head = bio;
 551
 552         bl->tail = bio;
 553 }
 554
 555 static inline void bio_list_add_head(struct bio_list *bl, struct bio *bio)
 556 {
 557         bio->bi_next = bl->head;
 558
 559         bl->head = bio;
 560
 561         if (!bl->tail)
 562                 bl->tail = bio;
 563 }
 564
 565 static inline void bio_list_merge(struct bio_list *bl, struct bio_list *bl2)
 566 {
 567         if (!bl2->head)
 568                 return;
 569
 570         if (bl->tail)
 571                 bl->tail->bi_next = bl2->head;
 572         else
 573                 bl->head = bl2->head;
 574
 575         bl->tail = bl2->tail;
 576 }
 577
 578 static inline void bio_list_merge_head(struct bio_list *bl,
 579                                        struct bio_list *bl2)
 580 {
 581         if (!bl2->head)
 582                 return;
 583
 584         if (bl->head)
 585                 bl2->tail->bi_next = bl->head;
 586         else
 587                 bl->tail = bl2->tail;
 588
 589         bl->head = bl2->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(struct bio *, gfp_t, unsigned int);
 632 extern void bio_integrity_free(struct bio *);
 633 extern int bio_integrity_add_page(struct bio *, struct page *, unsigned int, unsigned int);
 634 extern int bio_integrity_enabled(struct bio *bio);
 635 extern int bio_integrity_set_tag(struct bio *, void *, unsigned int);
 636 extern int bio_integrity_get_tag(struct bio *, void *, unsigned int);
 637 extern int bio_integrity_prep(struct bio *);
 638 extern void bio_integrity_endio(struct bio *, int);
 639 extern void bio_integrity_advance(struct bio *, unsigned int);
 640 extern void bio_integrity_trim(struct bio *, unsigned int, unsigned int);
 641 extern void bio_integrity_split(struct bio *, struct bio_pair *, int);
 642 extern int bio_integrity_clone(struct bio *, struct bio *, gfp_t);
 643
 644 #else /* CONFIG_BLK_DEV_INTEGRITY */
 645
 646 #define bio_integrity(a)                (0)
 647 #define bio_integrity_prep(a)           (0)
 648 #define bio_integrity_enabled(a)        (0)
 649 #define bio_integrity_clone(a, b, c)    (0)
 650 #define bio_integrity_free(a)           do { } while (0)
 651 #define bio_integrity_endio(a, b)       do { } while (0)
 652 #define bio_integrity_advance(a, b)     do { } while (0)
 653 #define bio_integrity_trim(a, b, c)     do { } while (0)
 654 #define bio_integrity_split(a, b, c)    do { } while (0)
 655 #define bio_integrity_set_tag(a, b, c)  do { } while (0)
 656 #define bio_integrity_get_tag(a, b, c)  do { } while (0)
 657
 658 #endif /* CONFIG_BLK_DEV_INTEGRITY */
 659
 660 #endif /* CONFIG_BLOCK */
 661 #endif /* __LINUX_BIO_H */