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 -- rw-ahead when set
 146  * bit 2 -- barrier
 147  *      Insert a serialization point in the IO queue, forcing previously
 148  *      submitted IO to be completed before this one is issued.
 149  * bit 3 -- synchronous I/O hint.
 150  * bit 4 -- Unplug the device immediately after submitting this bio.
 151  * bit 5 -- metadata request
 152  *      Used for tracing to differentiate metadata and data IO. May also
 153  *      get some preferential treatment in the IO scheduler
 154  * bit 6 -- discard sectors
 155  *      Informs the lower level device that this range of sectors is no longer
 156  *      used by the file system and may thus be freed by the device. Used
 157  *      for flash based storage.
 158  * bit 7 -- fail fast device errors
 159  * bit 8 -- fail fast transport errors
 160  * bit 9 -- fail fast driver errors
 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 #define BIO_RW          0       /* Must match RW in req flags (blkdev.h) */
 166 #define BIO_RW_AHEAD    1       /* Must match FAILFAST in req flags */
 167 #define BIO_RW_BARRIER  2
 168 #define BIO_RW_SYNCIO   3
 169 #define BIO_RW_UNPLUG   4
 170 #define BIO_RW_META     5
 171 #define BIO_RW_DISCARD  6
 172 #define BIO_RW_FAILFAST_DEV             7
 173 #define BIO_RW_FAILFAST_TRANSPORT       8
 174 #define BIO_RW_FAILFAST_DRIVER          9
 175 #define BIO_RW_NOIDLE   10
 176
 177 #define bio_rw_flagged(bio, flag)       ((bio)->bi_rw & (1 << (flag)))
 178
 179 /*
 180  * Old defines, these should eventually be replaced by direct usage of
 181  * bio_rw_flagged()
 182  */
 183 #define bio_barrier(bio)        bio_rw_flagged(bio, BIO_RW_BARRIER)
 184 #define bio_sync(bio)           bio_rw_flagged(bio, BIO_RW_SYNCIO)
 185 #define bio_unplug(bio)         bio_rw_flagged(bio, BIO_RW_UNPLUG)
 186 #define bio_failfast_dev(bio)   bio_rw_flagged(bio, BIO_RW_FAILFAST_DEV)
 187 #define bio_failfast_transport(bio)     \
 188                 bio_rw_flagged(bio, BIO_RW_FAILFAST_TRANSPORT)
 189 #define bio_failfast_driver(bio)        \
 190                 bio_rw_flagged(bio, BIO_RW_FAILFAST_DRIVER)
 191 #define bio_rw_ahead(bio)       bio_rw_flagged(bio, BIO_RW_AHEAD)
 192 #define bio_rw_meta(bio)        bio_rw_flagged(bio, BIO_RW_META)
 193 #define bio_discard(bio)        bio_rw_flagged(bio, BIO_RW_DISCARD)
 194 #define bio_noidle(bio)         bio_rw_flagged(bio, BIO_RW_NOIDLE)
 195
 196 /*
 197  * upper 16 bits of bi_rw define the io priority of this bio
 198  */
 199 #define BIO_PRIO_SHIFT  (8 * sizeof(unsigned long) - IOPRIO_BITS)
 200 #define bio_prio(bio)   ((bio)->bi_rw >> BIO_PRIO_SHIFT)
 201 #define bio_prio_valid(bio)     ioprio_valid(bio_prio(bio))
 202
 203 #define bio_set_prio(bio, prio)         do {                    \
 204         WARN_ON(prio >= (1 << IOPRIO_BITS));                    \
 205         (bio)->bi_rw &= ((1UL << BIO_PRIO_SHIFT) - 1);          \
 206         (bio)->bi_rw |= ((unsigned long) (prio) << BIO_PRIO_SHIFT);     \
 207 } while (0)
 208
 209 /*
 210  * various member access, note that bio_data should of course not be used
 211  * on highmem page vectors
 212  */
 213 #define bio_iovec_idx(bio, idx) (&((bio)->bi_io_vec[(idx)]))
 214 #define bio_iovec(bio)          bio_iovec_idx((bio), (bio)->bi_idx)
 215 #define bio_page(bio)           bio_iovec((bio))->bv_page
 216 #define bio_offset(bio)         bio_iovec((bio))->bv_offset
 217 #define bio_segments(bio)       ((bio)->bi_vcnt - (bio)->bi_idx)
 218 #define bio_sectors(bio)        ((bio)->bi_size >> 9)
 219 #define bio_empty_barrier(bio)  (bio_barrier(bio) && !bio_has_data(bio) && !bio_discard(bio))
 220
 221 static inline unsigned int bio_cur_sectors(struct bio *bio)
 222 {
 223         if (bio->bi_vcnt)
 224                 return bio_iovec(bio)->bv_len >> 9;
 225         else /* dataless requests such as discard */
 226                 return bio->bi_size >> 9;
 227 }
 228
 229 static inline void *bio_data(struct bio *bio)
 230 {
 231         if (bio->bi_vcnt)
 232                 return page_address(bio_page(bio)) + bio_offset(bio);
 233
 234         return NULL;
 235 }
 236
 237 static inline int bio_has_allocated_vec(struct bio *bio)
 238 {
 239         return bio->bi_io_vec && bio->bi_io_vec != bio->bi_inline_vecs;
 240 }
 241
 242 /*
 243  * will die
 244  */
 245 #define bio_to_phys(bio)        (page_to_phys(bio_page((bio))) + (unsigned long) bio_offset((bio)))
 246 #define bvec_to_phys(bv)        (page_to_phys((bv)->bv_page) + (unsigned long) (bv)->bv_offset)
 247
 248 /*
 249  * queues that have highmem support enabled may still need to revert to
 250  * PIO transfers occasionally and thus map high pages temporarily. For
 251  * permanent PIO fall back, user is probably better off disabling highmem
 252  * I/O completely on that queue (see ide-dma for example)
 253  */
 254 #define __bio_kmap_atomic(bio, idx, kmtype)                             \
 255         (kmap_atomic(bio_iovec_idx((bio), (idx))->bv_page, kmtype) +    \
 256                 bio_iovec_idx((bio), (idx))->bv_offset)
 257
 258 #define __bio_kunmap_atomic(addr, kmtype) kunmap_atomic(addr, kmtype)
 259
 260 /*
 261  * merge helpers etc
 262  */
 263
 264 #define __BVEC_END(bio)         bio_iovec_idx((bio), (bio)->bi_vcnt - 1)
 265 #define __BVEC_START(bio)       bio_iovec_idx((bio), (bio)->bi_idx)
 266
 267 /* Default implementation of BIOVEC_PHYS_MERGEABLE */
 268 #define __BIOVEC_PHYS_MERGEABLE(vec1, vec2)     \
 269         ((bvec_to_phys((vec1)) + (vec1)->bv_len) == bvec_to_phys((vec2)))
 270
 271 /*
 272  * allow arch override, for eg virtualized architectures (put in asm/io.h)
 273  */
 274 #ifndef BIOVEC_PHYS_MERGEABLE
 275 #define BIOVEC_PHYS_MERGEABLE(vec1, vec2)       \
 276         __BIOVEC_PHYS_MERGEABLE(vec1, vec2)
 277 #endif
 278
 279 #define __BIO_SEG_BOUNDARY(addr1, addr2, mask) \
 280         (((addr1) | (mask)) == (((addr2) - 1) | (mask)))
 281 #define BIOVEC_SEG_BOUNDARY(q, b1, b2) \
 282         __BIO_SEG_BOUNDARY(bvec_to_phys((b1)), bvec_to_phys((b2)) + (b2)->bv_len, (q)->seg_boundary_mask)
 283 #define BIO_SEG_BOUNDARY(q, b1, b2) \
 284         BIOVEC_SEG_BOUNDARY((q), __BVEC_END((b1)), __BVEC_START((b2)))
 285
 286 #define bio_io_error(bio) bio_endio((bio), -EIO)
 287
 288 /*
 289  * drivers should not use the __ version unless they _really_ want to
 290  * run through the entire bio and not just pending pieces
 291  */
 292 #define __bio_for_each_segment(bvl, bio, i, start_idx)                  \
 293         for (bvl = bio_iovec_idx((bio), (start_idx)), i = (start_idx);  \
 294              i < (bio)->bi_vcnt;                                        \
 295              bvl++, i++)
 296
 297 #define bio_for_each_segment(bvl, bio, i)                               \
 298         __bio_for_each_segment(bvl, bio, i, (bio)->bi_idx)
 299
 300 /*
 301  * get a reference to a bio, so it won't disappear. the intended use is
 302  * something like:
 303  *
 304  * bio_get(bio);
 305  * submit_bio(rw, bio);
 306  * if (bio->bi_flags ...)
 307  *      do_something
 308  * bio_put(bio);
 309  *
 310  * without the bio_get(), it could potentially complete I/O before submit_bio
 311  * returns. and then bio would be freed memory when if (bio->bi_flags ...)
 312  * runs
 313  */
 314 #define bio_get(bio)    atomic_inc(&(bio)->bi_cnt)
 315
 316 #if defined(CONFIG_BLK_DEV_INTEGRITY)
 317 /*
 318  * bio integrity payload
 319  */
 320 struct bio_integrity_payload {
 321         struct bio              *bip_bio;       /* parent bio */
 322         struct bio_vec          *bip_vec;       /* integrity data vector */
 323
 324         sector_t                bip_sector;     /* virtual start sector */
 325
 326         void                    *bip_buf;       /* generated integrity data */
 327         bio_end_io_t            *bip_end_io;    /* saved I/O completion fn */
 328
 329         unsigned int            bip_size;
 330
 331         unsigned short          bip_pool;       /* pool the ivec came from */
 332         unsigned short          bip_vcnt;       /* # of integrity bio_vecs */
 333         unsigned short          bip_idx;        /* current bip_vec index */
 334
 335         struct work_struct      bip_work;       /* I/O completion */
 336 };
 337 #endif /* CONFIG_BLK_DEV_INTEGRITY */
 338
 339 /*
 340  * A bio_pair is used when we need to split a bio.
 341  * This can only happen for a bio that refers to just one
 342  * page of data, and in the unusual situation when the
 343  * page crosses a chunk/device boundary
 344  *
 345  * The address of the master bio is stored in bio1.bi_private
 346  * The address of the pool the pair was allocated from is stored
 347  *   in bio2.bi_private
 348  */
 349 struct bio_pair {
 350         struct bio                      bio1, bio2;
 351         struct bio_vec                  bv1, bv2;
 352 #if defined(CONFIG_BLK_DEV_INTEGRITY)
 353         struct bio_integrity_payload    bip1, bip2;
 354         struct bio_vec                  iv1, iv2;
 355 #endif
 356         atomic_t                        cnt;
 357         int                             error;
 358 };
 359 extern struct bio_pair *bio_split(struct bio *bi, int first_sectors);
 360 extern void bio_pair_release(struct bio_pair *dbio);
 361
 362 extern struct bio_set *bioset_create(unsigned int, unsigned int);
 363 extern void bioset_free(struct bio_set *);
 364
 365 extern struct bio *bio_alloc(gfp_t, int);
 366 extern struct bio *bio_kmalloc(gfp_t, int);
 367 extern struct bio *bio_alloc_bioset(gfp_t, int, struct bio_set *);
 368 extern void bio_put(struct bio *);
 369 extern void bio_free(struct bio *, struct bio_set *);
 370
 371 extern void bio_endio(struct bio *, int);
 372 struct request_queue;
 373 extern int bio_phys_segments(struct request_queue *, struct bio *);
 374
 375 extern void __bio_clone(struct bio *, struct bio *);
 376 extern struct bio *bio_clone(struct bio *, gfp_t);
 377
 378 extern void bio_init(struct bio *);
 379
 380 extern int bio_add_page(struct bio *, struct page *, unsigned int,unsigned int);
 381 extern int bio_add_pc_page(struct request_queue *, struct bio *, struct page *,
 382                            unsigned int, unsigned int);
 383 extern int bio_get_nr_vecs(struct block_device *);
 384 extern sector_t bio_sector_offset(struct bio *, unsigned short, unsigned int);
 385 extern struct bio *bio_map_user(struct request_queue *, struct block_device *,
 386                                 unsigned long, unsigned int, int, gfp_t);
 387 struct sg_iovec;
 388 struct rq_map_data;
 389 extern struct bio *bio_map_user_iov(struct request_queue *,
 390                                     struct block_device *,
 391                                     struct sg_iovec *, int, int, gfp_t);
 392 extern void bio_unmap_user(struct bio *);
 393 extern struct bio *bio_map_kern(struct request_queue *, void *, unsigned int,
 394                                 gfp_t);
 395 extern struct bio *bio_copy_kern(struct request_queue *, void *, unsigned int,
 396                                  gfp_t, int);
 397 extern void bio_set_pages_dirty(struct bio *bio);
 398 extern void bio_check_pages_dirty(struct bio *bio);
 399 extern struct bio *bio_copy_user(struct request_queue *, struct rq_map_data *,
 400                                  unsigned long, unsigned int, int, gfp_t);
 401 extern struct bio *bio_copy_user_iov(struct request_queue *,
 402                                      struct rq_map_data *, struct sg_iovec *,
 403                                      int, int, gfp_t);
 404 extern int bio_uncopy_user(struct bio *);
 405 void zero_fill_bio(struct bio *bio);
 406 extern struct bio_vec *bvec_alloc_bs(gfp_t, int, unsigned long *, struct bio_set *);
 407 extern void bvec_free_bs(struct bio_set *, struct bio_vec *, unsigned int);
 408 extern unsigned int bvec_nr_vecs(unsigned short idx);
 409
 410 /*
 411  * Allow queuer to specify a completion CPU for this bio
 412  */
 413 static inline void bio_set_completion_cpu(struct bio *bio, unsigned int cpu)
 414 {
 415         bio->bi_comp_cpu = cpu;
 416 }
 417
 418 /*
 419  * bio_set is used to allow other portions of the IO system to
 420  * allocate their own private memory pools for bio and iovec structures.
 421  * These memory pools in turn all allocate from the bio_slab
 422  * and the bvec_slabs[].
 423  */
 424 #define BIO_POOL_SIZE 2
 425 #define BIOVEC_NR_POOLS 6
 426 #define BIOVEC_MAX_IDX  (BIOVEC_NR_POOLS - 1)
 427
 428 struct bio_set {
 429         struct kmem_cache *bio_slab;
 430         unsigned int front_pad;
 431
 432         mempool_t *bio_pool;
 433         mempool_t *bvec_pool;
 434 };
 435
 436 struct biovec_slab {
 437         int nr_vecs;
 438         char *name;
 439         struct kmem_cache *slab;
 440 };
 441
 442 extern struct bio_set *fs_bio_set;
 443 extern struct biovec_slab bvec_slabs[BIOVEC_NR_POOLS] __read_mostly;
 444
 445 /*
 446  * a small number of entries is fine, not going to be performance critical.
 447  * basically we just need to survive
 448  */
 449 #define BIO_SPLIT_ENTRIES 2
 450
 451 #ifdef CONFIG_HIGHMEM
 452 /*
 453  * remember never ever reenable interrupts between a bvec_kmap_irq and
 454  * bvec_kunmap_irq!
 455  *
 456  * This function MUST be inlined - it plays with the CPU interrupt flags.
 457  */
 458 static __always_inline char *bvec_kmap_irq(struct bio_vec *bvec,
 459                 unsigned long *flags)
 460 {
 461         unsigned long addr;
 462
 463         /*
 464          * might not be a highmem page, but the preempt/irq count
 465          * balancing is a lot nicer this way
 466          */
 467         local_irq_save(*flags);
 468         addr = (unsigned long) kmap_atomic(bvec->bv_page, KM_BIO_SRC_IRQ);
 469
 470         BUG_ON(addr & ~PAGE_MASK);
 471
 472         return (char *) addr + bvec->bv_offset;
 473 }
 474
 475 static __always_inline void bvec_kunmap_irq(char *buffer,
 476                 unsigned long *flags)
 477 {
 478         unsigned long ptr = (unsigned long) buffer & PAGE_MASK;
 479
 480         kunmap_atomic((void *) ptr, KM_BIO_SRC_IRQ);
 481         local_irq_restore(*flags);
 482 }
 483
 484 #else
 485 #define bvec_kmap_irq(bvec, flags)      (page_address((bvec)->bv_page) + (bvec)->bv_offset)
 486 #define bvec_kunmap_irq(buf, flags)     do { *(flags) = 0; } while (0)
 487 #endif
 488
 489 static inline char *__bio_kmap_irq(struct bio *bio, unsigned short idx,
 490                                    unsigned long *flags)
 491 {
 492         return bvec_kmap_irq(bio_iovec_idx(bio, idx), flags);
 493 }
 494 #define __bio_kunmap_irq(buf, flags)    bvec_kunmap_irq(buf, flags)
 495
 496 #define bio_kmap_irq(bio, flags) \
 497         __bio_kmap_irq((bio), (bio)->bi_idx, (flags))
 498 #define bio_kunmap_irq(buf,flags)       __bio_kunmap_irq(buf, flags)
 499
 500 /*
 501  * Check whether this bio carries any data or not. A NULL bio is allowed.
 502  */
 503 static inline int bio_has_data(struct bio *bio)
 504 {
 505         return bio && bio->bi_io_vec != NULL;
 506 }
 507
 508 /*
 509  * BIO list managment for use by remapping drivers (e.g. DM or MD).
 510  *
 511  * A bio_list anchors a singly-linked list of bios chained through the bi_next
 512  * member of the bio.  The bio_list also caches the last list member to allow
 513  * fast access to the tail.
 514  */
 515 struct bio_list {
 516         struct bio *head;
 517         struct bio *tail;
 518 };
 519
 520 static inline int bio_list_empty(const struct bio_list *bl)
 521 {
 522         return bl->head == NULL;
 523 }
 524
 525 static inline void bio_list_init(struct bio_list *bl)
 526 {
 527         bl->head = bl->tail = NULL;
 528 }
 529
 530 #define bio_list_for_each(bio, bl) \
 531         for (bio = (bl)->head; bio; bio = bio->bi_next)
 532
 533 static inline unsigned bio_list_size(const struct bio_list *bl)
 534 {
 535         unsigned sz = 0;
 536         struct bio *bio;
 537
 538         bio_list_for_each(bio, bl)
 539                 sz++;
 540
 541         return sz;
 542 }
 543
 544 static inline void bio_list_add(struct bio_list *bl, struct bio *bio)
 545 {
 546         bio->bi_next = NULL;
 547
 548         if (bl->tail)
 549                 bl->tail->bi_next = bio;
 550         else
 551                 bl->head = bio;
 552
 553         bl->tail = bio;
 554 }
 555
 556 static inline void bio_list_add_head(struct bio_list *bl, struct bio *bio)
 557 {
 558         bio->bi_next = bl->head;
 559
 560         bl->head = bio;
 561
 562         if (!bl->tail)
 563                 bl->tail = bio;
 564 }
 565
 566 static inline void bio_list_merge(struct bio_list *bl, struct bio_list *bl2)
 567 {
 568         if (!bl2->head)
 569                 return;
 570
 571         if (bl->tail)
 572                 bl->tail->bi_next = bl2->head;
 573         else
 574                 bl->head = bl2->head;
 575
 576         bl->tail = bl2->tail;
 577 }
 578
 579 static inline void bio_list_merge_head(struct bio_list *bl,
 580                                        struct bio_list *bl2)
 581 {
 582         if (!bl2->head)
 583                 return;
 584
 585         if (bl->head)
 586                 bl2->tail->bi_next = bl->head;
 587         else
 588                 bl->tail = bl2->tail;
 589
 590         bl->head = bl2->head;
 591 }
 592
 593 static inline struct bio *bio_list_pop(struct bio_list *bl)
 594 {
 595         struct bio *bio = bl->head;
 596
 597         if (bio) {
 598                 bl->head = bl->head->bi_next;
 599                 if (!bl->head)
 600                         bl->tail = NULL;
 601
 602                 bio->bi_next = NULL;
 603         }
 604
 605         return bio;
 606 }
 607
 608 static inline struct bio *bio_list_get(struct bio_list *bl)
 609 {
 610         struct bio *bio = bl->head;
 611
 612         bl->head = bl->tail = NULL;
 613
 614         return bio;
 615 }
 616
 617 #if defined(CONFIG_BLK_DEV_INTEGRITY)
 618
 619 #define bip_vec_idx(bip, idx)   (&(bip->bip_vec[(idx)]))
 620 #define bip_vec(bip)            bip_vec_idx(bip, 0)
 621
 622 #define __bip_for_each_vec(bvl, bip, i, start_idx)                      \
 623         for (bvl = bip_vec_idx((bip), (start_idx)), i = (start_idx);    \
 624              i < (bip)->bip_vcnt;                                       \
 625              bvl++, i++)
 626
 627 #define bip_for_each_vec(bvl, bip, i)                                   \
 628         __bip_for_each_vec(bvl, bip, i, (bip)->bip_idx)
 629
 630 #define bio_integrity(bio) (bio->bi_integrity != NULL)
 631
 632 extern struct bio_integrity_payload *bio_integrity_alloc(struct bio *, gfp_t, unsigned int);
 633 extern void bio_integrity_free(struct bio *);
 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);
 644
 645 #else /* CONFIG_BLK_DEV_INTEGRITY */
 646
 647 #define bio_integrity(a)                (0)
 648 #define bio_integrity_prep(a)           (0)
 649 #define bio_integrity_enabled(a)        (0)
 650 #define bio_integrity_clone(a, b, c)    (0)
 651 #define bio_integrity_free(a)           do { } while (0)
 652 #define bio_integrity_endio(a, b)       do { } while (0)
 653 #define bio_integrity_advance(a, b)     do { } while (0)
 654 #define bio_integrity_trim(a, b, c)     do { } while (0)
 655 #define bio_integrity_split(a, b, c)    do { } while (0)
 656 #define bio_integrity_set_tag(a, b, c)  do { } while (0)
 657 #define bio_integrity_get_tag(a, b, c)  do { } while (0)
 658
 659 #endif /* CONFIG_BLK_DEV_INTEGRITY */
 660
 661 #endif /* CONFIG_BLOCK */
 662 #endif /* __LINUX_BIO_H */