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 #include <linux/bug.h>
  27
  28 #ifdef CONFIG_BLOCK
  29
  30 #include <asm/io.h>
  31
  32 /* struct bio, bio_vec and BIO_* flags are defined in blk_types.h */
  33 #include <linux/blk_types.h>
  34
  35 #define BIO_DEBUG
  36
  37 #ifdef BIO_DEBUG
  38 #define BIO_BUG_ON      BUG_ON
  39 #else
  40 #define BIO_BUG_ON
  41 #endif
  42
  43 #define BIO_MAX_PAGES           256
  44 #define BIO_MAX_SIZE            (BIO_MAX_PAGES << PAGE_CACHE_SHIFT)
  45 #define BIO_MAX_SECTORS         (BIO_MAX_SIZE >> 9)
  46
  47 /*
  48  * upper 16 bits of bi_rw define the io priority of this bio
  49  */
  50 #define BIO_PRIO_SHIFT  (8 * sizeof(unsigned long) - IOPRIO_BITS)
  51 #define bio_prio(bio)   ((bio)->bi_rw >> BIO_PRIO_SHIFT)
  52 #define bio_prio_valid(bio)     ioprio_valid(bio_prio(bio))
  53
  54 #define bio_set_prio(bio, prio)         do {                    \
  55         WARN_ON(prio >= (1 << IOPRIO_BITS));                    \
  56         (bio)->bi_rw &= ((1UL << BIO_PRIO_SHIFT) - 1);          \
  57         (bio)->bi_rw |= ((unsigned long) (prio) << BIO_PRIO_SHIFT);     \
  58 } while (0)
  59
  60 /*
  61  * various member access, note that bio_data should of course not be used
  62  * on highmem page vectors
  63  */
  64 #define __bvec_iter_bvec(bvec, iter)    (&(bvec)[(iter).bi_idx])
  65
  66 #define bvec_iter_page(bvec, iter)                              \
  67         (__bvec_iter_bvec((bvec), (iter))->bv_page)
  68
  69 #define bvec_iter_len(bvec, iter)                               \
  70         min((iter).bi_size,                                     \
  71             __bvec_iter_bvec((bvec), (iter))->bv_len - (iter).bi_bvec_done)
  72
  73 #define bvec_iter_offset(bvec, iter)                            \
  74         (__bvec_iter_bvec((bvec), (iter))->bv_offset + (iter).bi_bvec_done)
  75
  76 #define bvec_iter_bvec(bvec, iter)                              \
  77 ((struct bio_vec) {                                             \
  78         .bv_page        = bvec_iter_page((bvec), (iter)),       \
  79         .bv_len         = bvec_iter_len((bvec), (iter)),        \
  80         .bv_offset      = bvec_iter_offset((bvec), (iter)),     \
  81 })
  82
  83 #define bio_iter_iovec(bio, iter)                               \
  84         bvec_iter_bvec((bio)->bi_io_vec, (iter))
  85
  86 #define bio_iter_page(bio, iter)                                \
  87         bvec_iter_page((bio)->bi_io_vec, (iter))
  88 #define bio_iter_len(bio, iter)                                 \
  89         bvec_iter_len((bio)->bi_io_vec, (iter))
  90 #define bio_iter_offset(bio, iter)                              \
  91         bvec_iter_offset((bio)->bi_io_vec, (iter))
  92
  93 #define bio_page(bio)           bio_iter_page((bio), (bio)->bi_iter)
  94 #define bio_offset(bio)         bio_iter_offset((bio), (bio)->bi_iter)
  95 #define bio_iovec(bio)          bio_iter_iovec((bio), (bio)->bi_iter)
  96
  97 #define bio_multiple_segments(bio)                              \
  98         ((bio)->bi_iter.bi_size != bio_iovec(bio).bv_len)
  99 #define bio_sectors(bio)        ((bio)->bi_iter.bi_size >> 9)
 100 #define bio_end_sector(bio)     ((bio)->bi_iter.bi_sector + bio_sectors((bio)))
 101
 102 /*
 103  * Check whether this bio carries any data or not. A NULL bio is allowed.
 104  */
 105 static inline bool bio_has_data(struct bio *bio)
 106 {
 107         if (bio &&
 108             bio->bi_iter.bi_size &&
 109             !(bio->bi_rw & REQ_DISCARD))
 110                 return true;
 111
 112         return false;
 113 }
 114
 115 static inline bool bio_is_rw(struct bio *bio)
 116 {
 117         if (!bio_has_data(bio))
 118                 return false;
 119
 120         if (bio->bi_rw & BIO_NO_ADVANCE_ITER_MASK)
 121                 return false;
 122
 123         return true;
 124 }
 125
 126 static inline bool bio_mergeable(struct bio *bio)
 127 {
 128         if (bio->bi_rw & REQ_NOMERGE_FLAGS)
 129                 return false;
 130
 131         return true;
 132 }
 133
 134 static inline unsigned int bio_cur_bytes(struct bio *bio)
 135 {
 136         if (bio_has_data(bio))
 137                 return bio_iovec(bio).bv_len;
 138         else /* dataless requests such as discard */
 139                 return bio->bi_iter.bi_size;
 140 }
 141
 142 static inline void *bio_data(struct bio *bio)
 143 {
 144         if (bio_has_data(bio))
 145                 return page_address(bio_page(bio)) + bio_offset(bio);
 146
 147         return NULL;
 148 }
 149
 150 /*
 151  * will die
 152  */
 153 #define bio_to_phys(bio)        (page_to_phys(bio_page((bio))) + (unsigned long) bio_offset((bio)))
 154 #define bvec_to_phys(bv)        (page_to_phys((bv)->bv_page) + (unsigned long) (bv)->bv_offset)
 155
 156 /*
 157  * queues that have highmem support enabled may still need to revert to
 158  * PIO transfers occasionally and thus map high pages temporarily. For
 159  * permanent PIO fall back, user is probably better off disabling highmem
 160  * I/O completely on that queue (see ide-dma for example)
 161  */
 162 #define __bio_kmap_atomic(bio, iter)                            \
 163         (kmap_atomic(bio_iter_iovec((bio), (iter)).bv_page) +   \
 164                 bio_iter_iovec((bio), (iter)).bv_offset)
 165
 166 #define __bio_kunmap_atomic(addr)       kunmap_atomic(addr)
 167
 168 /*
 169  * merge helpers etc
 170  */
 171
 172 /* Default implementation of BIOVEC_PHYS_MERGEABLE */
 173 #define __BIOVEC_PHYS_MERGEABLE(vec1, vec2)     \
 174         ((bvec_to_phys((vec1)) + (vec1)->bv_len) == bvec_to_phys((vec2)))
 175
 176 /*
 177  * allow arch override, for eg virtualized architectures (put in asm/io.h)
 178  */
 179 #ifndef BIOVEC_PHYS_MERGEABLE
 180 #define BIOVEC_PHYS_MERGEABLE(vec1, vec2)       \
 181         __BIOVEC_PHYS_MERGEABLE(vec1, vec2)
 182 #endif
 183
 184 #define __BIO_SEG_BOUNDARY(addr1, addr2, mask) \
 185         (((addr1) | (mask)) == (((addr2) - 1) | (mask)))
 186 #define BIOVEC_SEG_BOUNDARY(q, b1, b2) \
 187         __BIO_SEG_BOUNDARY(bvec_to_phys((b1)), bvec_to_phys((b2)) + (b2)->bv_len, queue_segment_boundary((q)))
 188
 189 #define bio_io_error(bio) bio_endio((bio), -EIO)
 190
 191 /*
 192  * drivers should _never_ use the all version - the bio may have been split
 193  * before it got to the driver and the driver won't own all of it
 194  */
 195 #define bio_for_each_segment_all(bvl, bio, i)                           \
 196         for (i = 0, bvl = (bio)->bi_io_vec; i < (bio)->bi_vcnt; i++, bvl++)
 197
 198 static inline void bvec_iter_advance(struct bio_vec *bv, struct bvec_iter *iter,
 199                                      unsigned bytes)
 200 {
 201         WARN_ONCE(bytes > iter->bi_size,
 202                   "Attempted to advance past end of bvec iter\n");
 203
 204         while (bytes) {
 205                 unsigned len = min(bytes, bvec_iter_len(bv, *iter));
 206
 207                 bytes -= len;
 208                 iter->bi_size -= len;
 209                 iter->bi_bvec_done += len;
 210
 211                 if (iter->bi_bvec_done == __bvec_iter_bvec(bv, *iter)->bv_len) {
 212                         iter->bi_bvec_done = 0;
 213                         iter->bi_idx++;
 214                 }
 215         }
 216 }
 217
 218 #define for_each_bvec(bvl, bio_vec, iter, start)                        \
 219         for ((iter) = start;                                            \
 220              (bvl) = bvec_iter_bvec((bio_vec), (iter)),                 \
 221                 (iter).bi_size;                                         \
 222              bvec_iter_advance((bio_vec), &(iter), (bvl).bv_len))
 223
 224
 225 static inline void bio_advance_iter(struct bio *bio, struct bvec_iter *iter,
 226                                     unsigned bytes)
 227 {
 228         iter->bi_sector += bytes >> 9;
 229
 230         if (bio->bi_rw & BIO_NO_ADVANCE_ITER_MASK)
 231                 iter->bi_size -= bytes;
 232         else
 233                 bvec_iter_advance(bio->bi_io_vec, iter, bytes);
 234 }
 235
 236 #define __bio_for_each_segment(bvl, bio, iter, start)                   \
 237         for (iter = (start);                                            \
 238              (iter).bi_size &&                                          \
 239                 ((bvl = bio_iter_iovec((bio), (iter))), 1);             \
 240              bio_advance_iter((bio), &(iter), (bvl).bv_len))
 241
 242 #define bio_for_each_segment(bvl, bio, iter)                            \
 243         __bio_for_each_segment(bvl, bio, iter, (bio)->bi_iter)
 244
 245 #define bio_iter_last(bvec, iter) ((iter).bi_size == (bvec).bv_len)
 246
 247 static inline unsigned bio_segments(struct bio *bio)
 248 {
 249         unsigned segs = 0;
 250         struct bio_vec bv;
 251         struct bvec_iter iter;
 252
 253         bio_for_each_segment(bv, bio, iter)
 254                 segs++;
 255
 256         return segs;
 257 }
 258
 259 /*
 260  * get a reference to a bio, so it won't disappear. the intended use is
 261  * something like:
 262  *
 263  * bio_get(bio);
 264  * submit_bio(rw, bio);
 265  * if (bio->bi_flags ...)
 266  *      do_something
 267  * bio_put(bio);
 268  *
 269  * without the bio_get(), it could potentially complete I/O before submit_bio
 270  * returns. and then bio would be freed memory when if (bio->bi_flags ...)
 271  * runs
 272  */
 273 #define bio_get(bio)    atomic_inc(&(bio)->bi_cnt)
 274
 275 #if defined(CONFIG_BLK_DEV_INTEGRITY)
 276 /*
 277  * bio integrity payload
 278  */
 279 struct bio_integrity_payload {
 280         struct bio              *bip_bio;       /* parent bio */
 281
 282         struct bvec_iter        bip_iter;
 283
 284         /* kill - should just use bip_vec */
 285         void                    *bip_buf;       /* generated integrity data */
 286
 287         bio_end_io_t            *bip_end_io;    /* saved I/O completion fn */
 288
 289         unsigned short          bip_slab;       /* slab the bip came from */
 290         unsigned short          bip_vcnt;       /* # of integrity bio_vecs */
 291         unsigned                bip_owns_buf:1; /* should free bip_buf */
 292
 293         struct work_struct      bip_work;       /* I/O completion */
 294
 295         struct bio_vec          *bip_vec;
 296         struct bio_vec          bip_inline_vecs[0];/* embedded bvec array */
 297 };
 298 #endif /* CONFIG_BLK_DEV_INTEGRITY */
 299
 300 /*
 301  * A bio_pair is used when we need to split a bio.
 302  * This can only happen for a bio that refers to just one
 303  * page of data, and in the unusual situation when the
 304  * page crosses a chunk/device boundary
 305  *
 306  * The address of the master bio is stored in bio1.bi_private
 307  * The address of the pool the pair was allocated from is stored
 308  *   in bio2.bi_private
 309  */
 310 struct bio_pair {
 311         struct bio                      bio1, bio2;
 312         struct bio_vec                  bv1, bv2;
 313 #if defined(CONFIG_BLK_DEV_INTEGRITY)
 314         struct bio_integrity_payload    bip1, bip2;
 315         struct bio_vec                  iv1, iv2;
 316 #endif
 317         atomic_t                        cnt;
 318         int                             error;
 319 };
 320 extern struct bio_pair *bio_split(struct bio *bi, int first_sectors);
 321 extern void bio_pair_release(struct bio_pair *dbio);
 322 extern void bio_trim(struct bio *bio, int offset, int size);
 323
 324 extern struct bio_set *bioset_create(unsigned int, unsigned int);
 325 extern void bioset_free(struct bio_set *);
 326 extern mempool_t *biovec_create_pool(struct bio_set *bs, int pool_entries);
 327
 328 extern struct bio *bio_alloc_bioset(gfp_t, int, struct bio_set *);
 329 extern void bio_put(struct bio *);
 330
 331 extern void __bio_clone_fast(struct bio *, struct bio *);
 332 extern struct bio *bio_clone_fast(struct bio *, gfp_t, struct bio_set *);
 333 extern struct bio *bio_clone_bioset(struct bio *, gfp_t, struct bio_set *bs);
 334
 335 extern struct bio_set *fs_bio_set;
 336
 337 static inline struct bio *bio_alloc(gfp_t gfp_mask, unsigned int nr_iovecs)
 338 {
 339         return bio_alloc_bioset(gfp_mask, nr_iovecs, fs_bio_set);
 340 }
 341
 342 static inline struct bio *bio_clone(struct bio *bio, gfp_t gfp_mask)
 343 {
 344         return bio_clone_bioset(bio, gfp_mask, fs_bio_set);
 345 }
 346
 347 static inline struct bio *bio_kmalloc(gfp_t gfp_mask, unsigned int nr_iovecs)
 348 {
 349         return bio_alloc_bioset(gfp_mask, nr_iovecs, NULL);
 350 }
 351
 352 static inline struct bio *bio_clone_kmalloc(struct bio *bio, gfp_t gfp_mask)
 353 {
 354         return bio_clone_bioset(bio, gfp_mask, NULL);
 355
 356 }
 357
 358 extern void bio_endio(struct bio *, int);
 359 extern void bio_endio_nodec(struct bio *, int);
 360 struct request_queue;
 361 extern int bio_phys_segments(struct request_queue *, struct bio *);
 362
 363 extern int submit_bio_wait(int rw, struct bio *bio);
 364 extern void bio_advance(struct bio *, unsigned);
 365
 366 extern void bio_init(struct bio *);
 367 extern void bio_reset(struct bio *);
 368 void bio_chain(struct bio *, struct bio *);
 369
 370 extern int bio_add_page(struct bio *, struct page *, unsigned int,unsigned int);
 371 extern int bio_add_pc_page(struct request_queue *, struct bio *, struct page *,
 372                            unsigned int, unsigned int);
 373 extern int bio_get_nr_vecs(struct block_device *);
 374 extern struct bio *bio_map_user(struct request_queue *, struct block_device *,
 375                                 unsigned long, unsigned int, int, gfp_t);
 376 struct sg_iovec;
 377 struct rq_map_data;
 378 extern struct bio *bio_map_user_iov(struct request_queue *,
 379                                     struct block_device *,
 380                                     struct sg_iovec *, int, int, gfp_t);
 381 extern void bio_unmap_user(struct bio *);
 382 extern struct bio *bio_map_kern(struct request_queue *, void *, unsigned int,
 383                                 gfp_t);
 384 extern struct bio *bio_copy_kern(struct request_queue *, void *, unsigned int,
 385                                  gfp_t, int);
 386 extern void bio_set_pages_dirty(struct bio *bio);
 387 extern void bio_check_pages_dirty(struct bio *bio);
 388
 389 #ifndef ARCH_IMPLEMENTS_FLUSH_DCACHE_PAGE
 390 # error "You should define ARCH_IMPLEMENTS_FLUSH_DCACHE_PAGE for your platform"
 391 #endif
 392 #if ARCH_IMPLEMENTS_FLUSH_DCACHE_PAGE
 393 extern void bio_flush_dcache_pages(struct bio *bi);
 394 #else
 395 static inline void bio_flush_dcache_pages(struct bio *bi)
 396 {
 397 }
 398 #endif
 399
 400 extern void bio_copy_data(struct bio *dst, struct bio *src);
 401 extern int bio_alloc_pages(struct bio *bio, gfp_t gfp);
 402
 403 extern struct bio *bio_copy_user(struct request_queue *, struct rq_map_data *,
 404                                  unsigned long, unsigned int, int, gfp_t);
 405 extern struct bio *bio_copy_user_iov(struct request_queue *,
 406                                      struct rq_map_data *, struct sg_iovec *,
 407                                      int, int, gfp_t);
 408 extern int bio_uncopy_user(struct bio *);
 409 void zero_fill_bio(struct bio *bio);
 410 extern struct bio_vec *bvec_alloc(gfp_t, int, unsigned long *, mempool_t *);
 411 extern void bvec_free(mempool_t *, struct bio_vec *, unsigned int);
 412 extern unsigned int bvec_nr_vecs(unsigned short idx);
 413
 414 #ifdef CONFIG_BLK_CGROUP
 415 int bio_associate_current(struct bio *bio);
 416 void bio_disassociate_task(struct bio *bio);
 417 #else   /* CONFIG_BLK_CGROUP */
 418 static inline int bio_associate_current(struct bio *bio) { return -ENOENT; }
 419 static inline void bio_disassociate_task(struct bio *bio) { }
 420 #endif  /* CONFIG_BLK_CGROUP */
 421
 422 #ifdef CONFIG_HIGHMEM
 423 /*
 424  * remember never ever reenable interrupts between a bvec_kmap_irq and
 425  * bvec_kunmap_irq!
 426  */
 427 static inline char *bvec_kmap_irq(struct bio_vec *bvec, unsigned long *flags)
 428 {
 429         unsigned long addr;
 430
 431         /*
 432          * might not be a highmem page, but the preempt/irq count
 433          * balancing is a lot nicer this way
 434          */
 435         local_irq_save(*flags);
 436         addr = (unsigned long) kmap_atomic(bvec->bv_page);
 437
 438         BUG_ON(addr & ~PAGE_MASK);
 439
 440         return (char *) addr + bvec->bv_offset;
 441 }
 442
 443 static inline void bvec_kunmap_irq(char *buffer, unsigned long *flags)
 444 {
 445         unsigned long ptr = (unsigned long) buffer & PAGE_MASK;
 446
 447         kunmap_atomic((void *) ptr);
 448         local_irq_restore(*flags);
 449 }
 450
 451 #else
 452 static inline char *bvec_kmap_irq(struct bio_vec *bvec, unsigned long *flags)
 453 {
 454         return page_address(bvec->bv_page) + bvec->bv_offset;
 455 }
 456
 457 static inline void bvec_kunmap_irq(char *buffer, unsigned long *flags)
 458 {
 459         *flags = 0;
 460 }
 461 #endif
 462
 463 static inline char *__bio_kmap_irq(struct bio *bio, struct bvec_iter iter,
 464                                    unsigned long *flags)
 465 {
 466         return bvec_kmap_irq(&bio_iter_iovec(bio, iter), flags);
 467 }
 468 #define __bio_kunmap_irq(buf, flags)    bvec_kunmap_irq(buf, flags)
 469
 470 #define bio_kmap_irq(bio, flags) \
 471         __bio_kmap_irq((bio), (bio)->bi_iter, (flags))
 472 #define bio_kunmap_irq(buf,flags)       __bio_kunmap_irq(buf, flags)
 473
 474 /*
 475  * BIO list management for use by remapping drivers (e.g. DM or MD) and loop.
 476  *
 477  * A bio_list anchors a singly-linked list of bios chained through the bi_next
 478  * member of the bio.  The bio_list also caches the last list member to allow
 479  * fast access to the tail.
 480  */
 481 struct bio_list {
 482         struct bio *head;
 483         struct bio *tail;
 484 };
 485
 486 static inline int bio_list_empty(const struct bio_list *bl)
 487 {
 488         return bl->head == NULL;
 489 }
 490
 491 static inline void bio_list_init(struct bio_list *bl)
 492 {
 493         bl->head = bl->tail = NULL;
 494 }
 495
 496 #define BIO_EMPTY_LIST  { NULL, NULL }
 497
 498 #define bio_list_for_each(bio, bl) \
 499         for (bio = (bl)->head; bio; bio = bio->bi_next)
 500
 501 static inline unsigned bio_list_size(const struct bio_list *bl)
 502 {
 503         unsigned sz = 0;
 504         struct bio *bio;
 505
 506         bio_list_for_each(bio, bl)
 507                 sz++;
 508
 509         return sz;
 510 }
 511
 512 static inline void bio_list_add(struct bio_list *bl, struct bio *bio)
 513 {
 514         bio->bi_next = NULL;
 515
 516         if (bl->tail)
 517                 bl->tail->bi_next = bio;
 518         else
 519                 bl->head = bio;
 520
 521         bl->tail = bio;
 522 }
 523
 524 static inline void bio_list_add_head(struct bio_list *bl, struct bio *bio)
 525 {
 526         bio->bi_next = bl->head;
 527
 528         bl->head = bio;
 529
 530         if (!bl->tail)
 531                 bl->tail = bio;
 532 }
 533
 534 static inline void bio_list_merge(struct bio_list *bl, struct bio_list *bl2)
 535 {
 536         if (!bl2->head)
 537                 return;
 538
 539         if (bl->tail)
 540                 bl->tail->bi_next = bl2->head;
 541         else
 542                 bl->head = bl2->head;
 543
 544         bl->tail = bl2->tail;
 545 }
 546
 547 static inline void bio_list_merge_head(struct bio_list *bl,
 548                                        struct bio_list *bl2)
 549 {
 550         if (!bl2->head)
 551                 return;
 552
 553         if (bl->head)
 554                 bl2->tail->bi_next = bl->head;
 555         else
 556                 bl->tail = bl2->tail;
 557
 558         bl->head = bl2->head;
 559 }
 560
 561 static inline struct bio *bio_list_peek(struct bio_list *bl)
 562 {
 563         return bl->head;
 564 }
 565
 566 static inline struct bio *bio_list_pop(struct bio_list *bl)
 567 {
 568         struct bio *bio = bl->head;
 569
 570         if (bio) {
 571                 bl->head = bl->head->bi_next;
 572                 if (!bl->head)
 573                         bl->tail = NULL;
 574
 575                 bio->bi_next = NULL;
 576         }
 577
 578         return bio;
 579 }
 580
 581 static inline struct bio *bio_list_get(struct bio_list *bl)
 582 {
 583         struct bio *bio = bl->head;
 584
 585         bl->head = bl->tail = NULL;
 586
 587         return bio;
 588 }
 589
 590 /*
 591  * bio_set is used to allow other portions of the IO system to
 592  * allocate their own private memory pools for bio and iovec structures.
 593  * These memory pools in turn all allocate from the bio_slab
 594  * and the bvec_slabs[].
 595  */
 596 #define BIO_POOL_SIZE 2
 597 #define BIOVEC_NR_POOLS 6
 598 #define BIOVEC_MAX_IDX  (BIOVEC_NR_POOLS - 1)
 599
 600 struct bio_set {
 601         struct kmem_cache *bio_slab;
 602         unsigned int front_pad;
 603
 604         mempool_t *bio_pool;
 605         mempool_t *bvec_pool;
 606 #if defined(CONFIG_BLK_DEV_INTEGRITY)
 607         mempool_t *bio_integrity_pool;
 608         mempool_t *bvec_integrity_pool;
 609 #endif
 610
 611         /*
 612          * Deadlock avoidance for stacking block drivers: see comments in
 613          * bio_alloc_bioset() for details
 614          */
 615         spinlock_t              rescue_lock;
 616         struct bio_list         rescue_list;
 617         struct work_struct      rescue_work;
 618         struct workqueue_struct *rescue_workqueue;
 619 };
 620
 621 struct biovec_slab {
 622         int nr_vecs;
 623         char *name;
 624         struct kmem_cache *slab;
 625 };
 626
 627 /*
 628  * a small number of entries is fine, not going to be performance critical.
 629  * basically we just need to survive
 630  */
 631 #define BIO_SPLIT_ENTRIES 2
 632
 633 #if defined(CONFIG_BLK_DEV_INTEGRITY)
 634
 635
 636
 637 #define bip_vec_idx(bip, idx)   (&(bip->bip_vec[(idx)]))
 638
 639 #define bip_for_each_vec(bvl, bip, iter)                                \
 640         for_each_bvec(bvl, (bip)->bip_vec, iter, (bip)->bip_iter)
 641
 642 #define bio_for_each_integrity_vec(_bvl, _bio, _iter)                   \
 643         for_each_bio(_bio)                                              \
 644                 bip_for_each_vec(_bvl, _bio->bi_integrity, _iter)
 645
 646 #define bio_integrity(bio) (bio->bi_integrity != NULL)
 647
 648 extern struct bio_integrity_payload *bio_integrity_alloc(struct bio *, gfp_t, unsigned int);
 649 extern void bio_integrity_free(struct bio *);
 650 extern int bio_integrity_add_page(struct bio *, struct page *, unsigned int, unsigned int);
 651 extern int bio_integrity_enabled(struct bio *bio);
 652 extern int bio_integrity_set_tag(struct bio *, void *, unsigned int);
 653 extern int bio_integrity_get_tag(struct bio *, void *, unsigned int);
 654 extern int bio_integrity_prep(struct bio *);
 655 extern void bio_integrity_endio(struct bio *, int);
 656 extern void bio_integrity_advance(struct bio *, unsigned int);
 657 extern void bio_integrity_trim(struct bio *, unsigned int, unsigned int);
 658 extern void bio_integrity_split(struct bio *, struct bio_pair *, int);
 659 extern int bio_integrity_clone(struct bio *, struct bio *, gfp_t);
 660 extern int bioset_integrity_create(struct bio_set *, int);
 661 extern void bioset_integrity_free(struct bio_set *);
 662 extern void bio_integrity_init(void);
 663
 664 #else /* CONFIG_BLK_DEV_INTEGRITY */
 665
 666 static inline int bio_integrity(struct bio *bio)
 667 {
 668         return 0;
 669 }
 670
 671 static inline int bio_integrity_enabled(struct bio *bio)
 672 {
 673         return 0;
 674 }
 675
 676 static inline int bioset_integrity_create(struct bio_set *bs, int pool_size)
 677 {
 678         return 0;
 679 }
 680
 681 static inline void bioset_integrity_free (struct bio_set *bs)
 682 {
 683         return;
 684 }
 685
 686 static inline int bio_integrity_prep(struct bio *bio)
 687 {
 688         return 0;
 689 }
 690
 691 static inline void bio_integrity_free(struct bio *bio)
 692 {
 693         return;
 694 }
 695
 696 static inline int bio_integrity_clone(struct bio *bio, struct bio *bio_src,
 697                                       gfp_t gfp_mask)
 698 {
 699         return 0;
 700 }
 701
 702 static inline void bio_integrity_split(struct bio *bio, struct bio_pair *bp,
 703                                        int sectors)
 704 {
 705         return;
 706 }
 707
 708 static inline void bio_integrity_advance(struct bio *bio,
 709                                          unsigned int bytes_done)
 710 {
 711         return;
 712 }
 713
 714 static inline void bio_integrity_trim(struct bio *bio, unsigned int offset,
 715                                       unsigned int sectors)
 716 {
 717         return;
 718 }
 719
 720 static inline void bio_integrity_init(void)
 721 {
 722         return;
 723 }
 724
 725 #endif /* CONFIG_BLK_DEV_INTEGRITY */
 726
 727 #endif /* CONFIG_BLOCK */
 728 #endif /* __LINUX_BIO_H */