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 /*
 190  * Check if adding a bio_vec after bprv with offset would create a gap in
 191  * the SG list. Most drivers don't care about this, but some do.
 192  */
 193 static inline bool bvec_gap_to_prev(struct bio_vec *bprv, unsigned int offset)
 194 {
 195         return offset || ((bprv->bv_offset + bprv->bv_len) & (PAGE_SIZE - 1));
 196 }
 197
 198 #define bio_io_error(bio) bio_endio((bio), -EIO)
 199
 200 /*
 201  * drivers should _never_ use the all version - the bio may have been split
 202  * before it got to the driver and the driver won't own all of it
 203  */
 204 #define bio_for_each_segment_all(bvl, bio, i)                           \
 205         for (i = 0, bvl = (bio)->bi_io_vec; i < (bio)->bi_vcnt; i++, bvl++)
 206
 207 static inline void bvec_iter_advance(struct bio_vec *bv, struct bvec_iter *iter,
 208                                      unsigned bytes)
 209 {
 210         WARN_ONCE(bytes > iter->bi_size,
 211                   "Attempted to advance past end of bvec iter\n");
 212
 213         while (bytes) {
 214                 unsigned len = min(bytes, bvec_iter_len(bv, *iter));
 215
 216                 bytes -= len;
 217                 iter->bi_size -= len;
 218                 iter->bi_bvec_done += len;
 219
 220                 if (iter->bi_bvec_done == __bvec_iter_bvec(bv, *iter)->bv_len) {
 221                         iter->bi_bvec_done = 0;
 222                         iter->bi_idx++;
 223                 }
 224         }
 225 }
 226
 227 #define for_each_bvec(bvl, bio_vec, iter, start)                        \
 228         for (iter = (start);                                            \
 229              (iter).bi_size &&                                          \
 230                 ((bvl = bvec_iter_bvec((bio_vec), (iter))), 1); \
 231              bvec_iter_advance((bio_vec), &(iter), (bvl).bv_len))
 232
 233
 234 static inline void bio_advance_iter(struct bio *bio, struct bvec_iter *iter,
 235                                     unsigned bytes)
 236 {
 237         iter->bi_sector += bytes >> 9;
 238
 239         if (bio->bi_rw & BIO_NO_ADVANCE_ITER_MASK)
 240                 iter->bi_size -= bytes;
 241         else
 242                 bvec_iter_advance(bio->bi_io_vec, iter, bytes);
 243 }
 244
 245 #define __bio_for_each_segment(bvl, bio, iter, start)                   \
 246         for (iter = (start);                                            \
 247              (iter).bi_size &&                                          \
 248                 ((bvl = bio_iter_iovec((bio), (iter))), 1);             \
 249              bio_advance_iter((bio), &(iter), (bvl).bv_len))
 250
 251 #define bio_for_each_segment(bvl, bio, iter)                            \
 252         __bio_for_each_segment(bvl, bio, iter, (bio)->bi_iter)
 253
 254 #define bio_iter_last(bvec, iter) ((iter).bi_size == (bvec).bv_len)
 255
 256 static inline unsigned bio_segments(struct bio *bio)
 257 {
 258         unsigned segs = 0;
 259         struct bio_vec bv;
 260         struct bvec_iter iter;
 261
 262         /*
 263          * We special case discard/write same, because they interpret bi_size
 264          * differently:
 265          */
 266
 267         if (bio->bi_rw & REQ_DISCARD)
 268                 return 1;
 269
 270         if (bio->bi_rw & REQ_WRITE_SAME)
 271                 return 1;
 272
 273         bio_for_each_segment(bv, bio, iter)
 274                 segs++;
 275
 276         return segs;
 277 }
 278
 279 /*
 280  * get a reference to a bio, so it won't disappear. the intended use is
 281  * something like:
 282  *
 283  * bio_get(bio);
 284  * submit_bio(rw, bio);
 285  * if (bio->bi_flags ...)
 286  *      do_something
 287  * bio_put(bio);
 288  *
 289  * without the bio_get(), it could potentially complete I/O before submit_bio
 290  * returns. and then bio would be freed memory when if (bio->bi_flags ...)
 291  * runs
 292  */
 293 #define bio_get(bio)    atomic_inc(&(bio)->bi_cnt)
 294
 295 #if defined(CONFIG_BLK_DEV_INTEGRITY)
 296 /*
 297  * bio integrity payload
 298  */
 299 struct bio_integrity_payload {
 300         struct bio              *bip_bio;       /* parent bio */
 301
 302         struct bvec_iter        bip_iter;
 303
 304         /* kill - should just use bip_vec */
 305         void                    *bip_buf;       /* generated integrity data */
 306
 307         bio_end_io_t            *bip_end_io;    /* saved I/O completion fn */
 308
 309         unsigned short          bip_slab;       /* slab the bip came from */
 310         unsigned short          bip_vcnt;       /* # of integrity bio_vecs */
 311         unsigned short          bip_max_vcnt;   /* integrity bio_vec slots */
 312         unsigned                bip_owns_buf:1; /* should free bip_buf */
 313
 314         struct work_struct      bip_work;       /* I/O completion */
 315
 316         struct bio_vec          *bip_vec;
 317         struct bio_vec          bip_inline_vecs[0];/* embedded bvec array */
 318 };
 319 #endif /* CONFIG_BLK_DEV_INTEGRITY */
 320
 321 extern void bio_trim(struct bio *bio, int offset, int size);
 322 extern struct bio *bio_split(struct bio *bio, int sectors,
 323                              gfp_t gfp, struct bio_set *bs);
 324
 325 /**
 326  * bio_next_split - get next @sectors from a bio, splitting if necessary
 327  * @bio:        bio to split
 328  * @sectors:    number of sectors to split from the front of @bio
 329  * @gfp:        gfp mask
 330  * @bs:         bio set to allocate from
 331  *
 332  * Returns a bio representing the next @sectors of @bio - if the bio is smaller
 333  * than @sectors, returns the original bio unchanged.
 334  */
 335 static inline struct bio *bio_next_split(struct bio *bio, int sectors,
 336                                          gfp_t gfp, struct bio_set *bs)
 337 {
 338         if (sectors >= bio_sectors(bio))
 339                 return bio;
 340
 341         return bio_split(bio, sectors, gfp, bs);
 342 }
 343
 344 extern struct bio_set *bioset_create(unsigned int, unsigned int);
 345 extern void bioset_free(struct bio_set *);
 346 extern mempool_t *biovec_create_pool(int pool_entries);
 347
 348 extern struct bio *bio_alloc_bioset(gfp_t, int, struct bio_set *);
 349 extern void bio_put(struct bio *);
 350
 351 extern void __bio_clone_fast(struct bio *, struct bio *);
 352 extern struct bio *bio_clone_fast(struct bio *, gfp_t, struct bio_set *);
 353 extern struct bio *bio_clone_bioset(struct bio *, gfp_t, struct bio_set *bs);
 354
 355 extern struct bio_set *fs_bio_set;
 356 unsigned int bio_integrity_tag_size(struct bio *bio);
 357
 358 static inline struct bio *bio_alloc(gfp_t gfp_mask, unsigned int nr_iovecs)
 359 {
 360         return bio_alloc_bioset(gfp_mask, nr_iovecs, fs_bio_set);
 361 }
 362
 363 static inline struct bio *bio_clone(struct bio *bio, gfp_t gfp_mask)
 364 {
 365         return bio_clone_bioset(bio, gfp_mask, fs_bio_set);
 366 }
 367
 368 static inline struct bio *bio_kmalloc(gfp_t gfp_mask, unsigned int nr_iovecs)
 369 {
 370         return bio_alloc_bioset(gfp_mask, nr_iovecs, NULL);
 371 }
 372
 373 static inline struct bio *bio_clone_kmalloc(struct bio *bio, gfp_t gfp_mask)
 374 {
 375         return bio_clone_bioset(bio, gfp_mask, NULL);
 376
 377 }
 378
 379 extern void bio_endio(struct bio *, int);
 380 extern void bio_endio_nodec(struct bio *, int);
 381 struct request_queue;
 382 extern int bio_phys_segments(struct request_queue *, struct bio *);
 383
 384 extern int submit_bio_wait(int rw, struct bio *bio);
 385 extern void bio_advance(struct bio *, unsigned);
 386
 387 extern void bio_init(struct bio *);
 388 extern void bio_reset(struct bio *);
 389 void bio_chain(struct bio *, struct bio *);
 390
 391 extern int bio_add_page(struct bio *, struct page *, unsigned int,unsigned int);
 392 extern int bio_add_pc_page(struct request_queue *, struct bio *, struct page *,
 393                            unsigned int, unsigned int);
 394 extern int bio_get_nr_vecs(struct block_device *);
 395 extern struct bio *bio_map_user(struct request_queue *, struct block_device *,
 396                                 unsigned long, unsigned int, int, gfp_t);
 397 struct sg_iovec;
 398 struct rq_map_data;
 399 extern struct bio *bio_map_user_iov(struct request_queue *,
 400                                     struct block_device *,
 401                                     const struct sg_iovec *, int, int, gfp_t);
 402 extern void bio_unmap_user(struct bio *);
 403 extern struct bio *bio_map_kern(struct request_queue *, void *, unsigned int,
 404                                 gfp_t);
 405 extern struct bio *bio_copy_kern(struct request_queue *, void *, unsigned int,
 406                                  gfp_t, int);
 407 extern void bio_set_pages_dirty(struct bio *bio);
 408 extern void bio_check_pages_dirty(struct bio *bio);
 409
 410 #ifndef ARCH_IMPLEMENTS_FLUSH_DCACHE_PAGE
 411 # error "You should define ARCH_IMPLEMENTS_FLUSH_DCACHE_PAGE for your platform"
 412 #endif
 413 #if ARCH_IMPLEMENTS_FLUSH_DCACHE_PAGE
 414 extern void bio_flush_dcache_pages(struct bio *bi);
 415 #else
 416 static inline void bio_flush_dcache_pages(struct bio *bi)
 417 {
 418 }
 419 #endif
 420
 421 extern void bio_copy_data(struct bio *dst, struct bio *src);
 422 extern int bio_alloc_pages(struct bio *bio, gfp_t gfp);
 423
 424 extern struct bio *bio_copy_user(struct request_queue *, struct rq_map_data *,
 425                                  unsigned long, unsigned int, int, gfp_t);
 426 extern struct bio *bio_copy_user_iov(struct request_queue *,
 427                                      struct rq_map_data *,
 428                                      const struct sg_iovec *,
 429                                      int, int, gfp_t);
 430 extern int bio_uncopy_user(struct bio *);
 431 void zero_fill_bio(struct bio *bio);
 432 extern struct bio_vec *bvec_alloc(gfp_t, int, unsigned long *, mempool_t *);
 433 extern void bvec_free(mempool_t *, struct bio_vec *, unsigned int);
 434 extern unsigned int bvec_nr_vecs(unsigned short idx);
 435
 436 #ifdef CONFIG_BLK_CGROUP
 437 int bio_associate_current(struct bio *bio);
 438 void bio_disassociate_task(struct bio *bio);
 439 #else   /* CONFIG_BLK_CGROUP */
 440 static inline int bio_associate_current(struct bio *bio) { return -ENOENT; }
 441 static inline void bio_disassociate_task(struct bio *bio) { }
 442 #endif  /* CONFIG_BLK_CGROUP */
 443
 444 #ifdef CONFIG_HIGHMEM
 445 /*
 446  * remember never ever reenable interrupts between a bvec_kmap_irq and
 447  * bvec_kunmap_irq!
 448  */
 449 static inline char *bvec_kmap_irq(struct bio_vec *bvec, unsigned long *flags)
 450 {
 451         unsigned long addr;
 452
 453         /*
 454          * might not be a highmem page, but the preempt/irq count
 455          * balancing is a lot nicer this way
 456          */
 457         local_irq_save(*flags);
 458         addr = (unsigned long) kmap_atomic(bvec->bv_page);
 459
 460         BUG_ON(addr & ~PAGE_MASK);
 461
 462         return (char *) addr + bvec->bv_offset;
 463 }
 464
 465 static inline void bvec_kunmap_irq(char *buffer, unsigned long *flags)
 466 {
 467         unsigned long ptr = (unsigned long) buffer & PAGE_MASK;
 468
 469         kunmap_atomic((void *) ptr);
 470         local_irq_restore(*flags);
 471 }
 472
 473 #else
 474 static inline char *bvec_kmap_irq(struct bio_vec *bvec, unsigned long *flags)
 475 {
 476         return page_address(bvec->bv_page) + bvec->bv_offset;
 477 }
 478
 479 static inline void bvec_kunmap_irq(char *buffer, unsigned long *flags)
 480 {
 481         *flags = 0;
 482 }
 483 #endif
 484
 485 static inline char *__bio_kmap_irq(struct bio *bio, struct bvec_iter iter,
 486                                    unsigned long *flags)
 487 {
 488         return bvec_kmap_irq(&bio_iter_iovec(bio, iter), flags);
 489 }
 490 #define __bio_kunmap_irq(buf, flags)    bvec_kunmap_irq(buf, flags)
 491
 492 #define bio_kmap_irq(bio, flags) \
 493         __bio_kmap_irq((bio), (bio)->bi_iter, (flags))
 494 #define bio_kunmap_irq(buf,flags)       __bio_kunmap_irq(buf, flags)
 495
 496 /*
 497  * BIO list management for use by remapping drivers (e.g. DM or MD) and loop.
 498  *
 499  * A bio_list anchors a singly-linked list of bios chained through the bi_next
 500  * member of the bio.  The bio_list also caches the last list member to allow
 501  * fast access to the tail.
 502  */
 503 struct bio_list {
 504         struct bio *head;
 505         struct bio *tail;
 506 };
 507
 508 static inline int bio_list_empty(const struct bio_list *bl)
 509 {
 510         return bl->head == NULL;
 511 }
 512
 513 static inline void bio_list_init(struct bio_list *bl)
 514 {
 515         bl->head = bl->tail = NULL;
 516 }
 517
 518 #define BIO_EMPTY_LIST  { NULL, NULL }
 519
 520 #define bio_list_for_each(bio, bl) \
 521         for (bio = (bl)->head; bio; bio = bio->bi_next)
 522
 523 static inline unsigned bio_list_size(const struct bio_list *bl)
 524 {
 525         unsigned sz = 0;
 526         struct bio *bio;
 527
 528         bio_list_for_each(bio, bl)
 529                 sz++;
 530
 531         return sz;
 532 }
 533
 534 static inline void bio_list_add(struct bio_list *bl, struct bio *bio)
 535 {
 536         bio->bi_next = NULL;
 537
 538         if (bl->tail)
 539                 bl->tail->bi_next = bio;
 540         else
 541                 bl->head = bio;
 542
 543         bl->tail = bio;
 544 }
 545
 546 static inline void bio_list_add_head(struct bio_list *bl, struct bio *bio)
 547 {
 548         bio->bi_next = bl->head;
 549
 550         bl->head = bio;
 551
 552         if (!bl->tail)
 553                 bl->tail = bio;
 554 }
 555
 556 static inline void bio_list_merge(struct bio_list *bl, struct bio_list *bl2)
 557 {
 558         if (!bl2->head)
 559                 return;
 560
 561         if (bl->tail)
 562                 bl->tail->bi_next = bl2->head;
 563         else
 564                 bl->head = bl2->head;
 565
 566         bl->tail = bl2->tail;
 567 }
 568
 569 static inline void bio_list_merge_head(struct bio_list *bl,
 570                                        struct bio_list *bl2)
 571 {
 572         if (!bl2->head)
 573                 return;
 574
 575         if (bl->head)
 576                 bl2->tail->bi_next = bl->head;
 577         else
 578                 bl->tail = bl2->tail;
 579
 580         bl->head = bl2->head;
 581 }
 582
 583 static inline struct bio *bio_list_peek(struct bio_list *bl)
 584 {
 585         return bl->head;
 586 }
 587
 588 static inline struct bio *bio_list_pop(struct bio_list *bl)
 589 {
 590         struct bio *bio = bl->head;
 591
 592         if (bio) {
 593                 bl->head = bl->head->bi_next;
 594                 if (!bl->head)
 595                         bl->tail = NULL;
 596
 597                 bio->bi_next = NULL;
 598         }
 599
 600         return bio;
 601 }
 602
 603 static inline struct bio *bio_list_get(struct bio_list *bl)
 604 {
 605         struct bio *bio = bl->head;
 606
 607         bl->head = bl->tail = NULL;
 608
 609         return bio;
 610 }
 611
 612 /*
 613  * bio_set is used to allow other portions of the IO system to
 614  * allocate their own private memory pools for bio and iovec structures.
 615  * These memory pools in turn all allocate from the bio_slab
 616  * and the bvec_slabs[].
 617  */
 618 #define BIO_POOL_SIZE 2
 619 #define BIOVEC_NR_POOLS 6
 620 #define BIOVEC_MAX_IDX  (BIOVEC_NR_POOLS - 1)
 621
 622 struct bio_set {
 623         struct kmem_cache *bio_slab;
 624         unsigned int front_pad;
 625
 626         mempool_t *bio_pool;
 627         mempool_t *bvec_pool;
 628 #if defined(CONFIG_BLK_DEV_INTEGRITY)
 629         mempool_t *bio_integrity_pool;
 630         mempool_t *bvec_integrity_pool;
 631 #endif
 632
 633         /*
 634          * Deadlock avoidance for stacking block drivers: see comments in
 635          * bio_alloc_bioset() for details
 636          */
 637         spinlock_t              rescue_lock;
 638         struct bio_list         rescue_list;
 639         struct work_struct      rescue_work;
 640         struct workqueue_struct *rescue_workqueue;
 641 };
 642
 643 struct biovec_slab {
 644         int nr_vecs;
 645         char *name;
 646         struct kmem_cache *slab;
 647 };
 648
 649 /*
 650  * a small number of entries is fine, not going to be performance critical.
 651  * basically we just need to survive
 652  */
 653 #define BIO_SPLIT_ENTRIES 2
 654
 655 #if defined(CONFIG_BLK_DEV_INTEGRITY)
 656
 657 #define bip_for_each_vec(bvl, bip, iter)                                \
 658         for_each_bvec(bvl, (bip)->bip_vec, iter, (bip)->bip_iter)
 659
 660 #define bio_for_each_integrity_vec(_bvl, _bio, _iter)                   \
 661         for_each_bio(_bio)                                              \
 662                 bip_for_each_vec(_bvl, _bio->bi_integrity, _iter)
 663
 664 #define bio_integrity(bio) (bio->bi_integrity != NULL)
 665
 666 extern struct bio_integrity_payload *bio_integrity_alloc(struct bio *, gfp_t, unsigned int);
 667 extern void bio_integrity_free(struct bio *);
 668 extern int bio_integrity_add_page(struct bio *, struct page *, unsigned int, unsigned int);
 669 extern int bio_integrity_enabled(struct bio *bio);
 670 extern int bio_integrity_set_tag(struct bio *, void *, unsigned int);
 671 extern int bio_integrity_get_tag(struct bio *, void *, unsigned int);
 672 extern int bio_integrity_prep(struct bio *);
 673 extern void bio_integrity_endio(struct bio *, int);
 674 extern void bio_integrity_advance(struct bio *, unsigned int);
 675 extern void bio_integrity_trim(struct bio *, unsigned int, unsigned int);
 676 extern int bio_integrity_clone(struct bio *, struct bio *, gfp_t);
 677 extern int bioset_integrity_create(struct bio_set *, int);
 678 extern void bioset_integrity_free(struct bio_set *);
 679 extern void bio_integrity_init(void);
 680
 681 #else /* CONFIG_BLK_DEV_INTEGRITY */
 682
 683 static inline int bio_integrity(struct bio *bio)
 684 {
 685         return 0;
 686 }
 687
 688 static inline int bio_integrity_enabled(struct bio *bio)
 689 {
 690         return 0;
 691 }
 692
 693 static inline int bioset_integrity_create(struct bio_set *bs, int pool_size)
 694 {
 695         return 0;
 696 }
 697
 698 static inline void bioset_integrity_free (struct bio_set *bs)
 699 {
 700         return;
 701 }
 702
 703 static inline int bio_integrity_prep(struct bio *bio)
 704 {
 705         return 0;
 706 }
 707
 708 static inline void bio_integrity_free(struct bio *bio)
 709 {
 710         return;
 711 }
 712
 713 static inline int bio_integrity_clone(struct bio *bio, struct bio *bio_src,
 714                                       gfp_t gfp_mask)
 715 {
 716         return 0;
 717 }
 718
 719 static inline void bio_integrity_advance(struct bio *bio,
 720                                          unsigned int bytes_done)
 721 {
 722         return;
 723 }
 724
 725 static inline void bio_integrity_trim(struct bio *bio, unsigned int offset,
 726                                       unsigned int sectors)
 727 {
 728         return;
 729 }
 730
 731 static inline void bio_integrity_init(void)
 732 {
 733         return;
 734 }
 735
 736 #endif /* CONFIG_BLK_DEV_INTEGRITY */
 737
 738 #endif /* CONFIG_BLOCK */
 739 #endif /* __LINUX_BIO_H */