include/linux/bio.h

   1 /*
   2  * Copyright (C) 2001 Jens Axboe <axboe@suse.de>
   3  *
   4  * This program is free software; you can redistribute it and/or modify
   5  * it under the terms of the GNU General Public License version 2 as
   6  * published by the Free Software Foundation.
   7  *
   8  * This program is distributed in the hope that it will be useful,
   9  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  10  *
  11  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  12  * GNU General Public License for more details.
  13  *
  14  * You should have received a copy of the GNU General Public Licens
  15  * along with this program; if not, write to the Free Software
  16  * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-
  17  */
  18 #ifndef __LINUX_BIO_H
  19 #define __LINUX_BIO_H
  20
  21 #include <linux/highmem.h>
  22 #include <linux/mempool.h>
  23 #include <linux/ioprio.h>
  24 #include <linux/bug.h>
  25
  26 #ifdef CONFIG_BLOCK
  27
  28 #include <asm/io.h>
  29
  30 /* struct bio, bio_vec and BIO_* flags are defined in blk_types.h */
  31 #include <linux/blk_types.h>
  32
  33 #define BIO_DEBUG
  34
  35 #ifdef BIO_DEBUG
  36 #define BIO_BUG_ON      BUG_ON
  37 #else
  38 #define BIO_BUG_ON
  39 #endif
  40
  41 #define BIO_MAX_PAGES           256
  42
  43 #define bio_prio(bio)                   (bio)->bi_ioprio
  44 #define bio_set_prio(bio, prio)         ((bio)->bi_ioprio = prio)
  45
  46 #define bio_iter_iovec(bio, iter)                               \
  47         bvec_iter_bvec((bio)->bi_io_vec, (iter))
  48
  49 #define bio_iter_page(bio, iter)                                \
  50         bvec_iter_page((bio)->bi_io_vec, (iter))
  51 #define bio_iter_len(bio, iter)                                 \
  52         bvec_iter_len((bio)->bi_io_vec, (iter))
  53 #define bio_iter_offset(bio, iter)                              \
  54         bvec_iter_offset((bio)->bi_io_vec, (iter))
  55
  56 #define bio_page(bio)           bio_iter_page((bio), (bio)->bi_iter)
  57 #define bio_offset(bio)         bio_iter_offset((bio), (bio)->bi_iter)
  58 #define bio_iovec(bio)          bio_iter_iovec((bio), (bio)->bi_iter)
  59
  60 #define bio_multiple_segments(bio)                              \
  61         ((bio)->bi_iter.bi_size != bio_iovec(bio).bv_len)
  62 #define bio_sectors(bio)        ((bio)->bi_iter.bi_size >> 9)
  63 #define bio_end_sector(bio)     ((bio)->bi_iter.bi_sector + bio_sectors((bio)))
  64
  65 /*
  66  * Return the data direction, READ or WRITE.
  67  */
  68 #define bio_data_dir(bio) \
  69         (op_is_write(bio_op(bio)) ? WRITE : READ)
  70
  71 /*
  72  * Check whether this bio carries any data or not. A NULL bio is allowed.
  73  */
  74 static inline bool bio_has_data(struct bio *bio)
  75 {
  76         if (bio &&
  77             bio->bi_iter.bi_size &&
  78             bio_op(bio) != REQ_OP_DISCARD &&
  79             bio_op(bio) != REQ_OP_SECURE_ERASE)
  80                 return true;
  81
  82         return false;
  83 }
  84
  85 static inline bool bio_no_advance_iter(struct bio *bio)
  86 {
  87         return bio_op(bio) == REQ_OP_DISCARD ||
  88                bio_op(bio) == REQ_OP_SECURE_ERASE ||
  89                bio_op(bio) == REQ_OP_WRITE_SAME;
  90 }
  91
  92 static inline bool bio_mergeable(struct bio *bio)
  93 {
  94         if (bio->bi_opf & REQ_NOMERGE_FLAGS)
  95                 return false;
  96
  97         return true;
  98 }
  99
 100 static inline unsigned int bio_cur_bytes(struct bio *bio)
 101 {
 102         if (bio_has_data(bio))
 103                 return bio_iovec(bio).bv_len;
 104         else /* dataless requests such as discard */
 105                 return bio->bi_iter.bi_size;
 106 }
 107
 108 static inline void *bio_data(struct bio *bio)
 109 {
 110         if (bio_has_data(bio))
 111                 return page_address(bio_page(bio)) + bio_offset(bio);
 112
 113         return NULL;
 114 }
 115
 116 /*
 117  * will die
 118  */
 119 #define bio_to_phys(bio)        (page_to_phys(bio_page((bio))) + (unsigned long) bio_offset((bio)))
 120 #define bvec_to_phys(bv)        (page_to_phys((bv)->bv_page) + (unsigned long) (bv)->bv_offset)
 121
 122 /*
 123  * queues that have highmem support enabled may still need to revert to
 124  * PIO transfers occasionally and thus map high pages temporarily. For
 125  * permanent PIO fall back, user is probably better off disabling highmem
 126  * I/O completely on that queue (see ide-dma for example)
 127  */
 128 #define __bio_kmap_atomic(bio, iter)                            \
 129         (kmap_atomic(bio_iter_iovec((bio), (iter)).bv_page) +   \
 130                 bio_iter_iovec((bio), (iter)).bv_offset)
 131
 132 #define __bio_kunmap_atomic(addr)       kunmap_atomic(addr)
 133
 134 /*
 135  * merge helpers etc
 136  */
 137
 138 /* Default implementation of BIOVEC_PHYS_MERGEABLE */
 139 #define __BIOVEC_PHYS_MERGEABLE(vec1, vec2)     \
 140         ((bvec_to_phys((vec1)) + (vec1)->bv_len) == bvec_to_phys((vec2)))
 141
 142 /*
 143  * allow arch override, for eg virtualized architectures (put in asm/io.h)
 144  */
 145 #ifndef BIOVEC_PHYS_MERGEABLE
 146 #define BIOVEC_PHYS_MERGEABLE(vec1, vec2)       \
 147         __BIOVEC_PHYS_MERGEABLE(vec1, vec2)
 148 #endif
 149
 150 #define __BIO_SEG_BOUNDARY(addr1, addr2, mask) \
 151         (((addr1) | (mask)) == (((addr2) - 1) | (mask)))
 152 #define BIOVEC_SEG_BOUNDARY(q, b1, b2) \
 153         __BIO_SEG_BOUNDARY(bvec_to_phys((b1)), bvec_to_phys((b2)) + (b2)->bv_len, queue_segment_boundary((q)))
 154
 155 /*
 156  * drivers should _never_ use the all version - the bio may have been split
 157  * before it got to the driver and the driver won't own all of it
 158  */
 159 #define bio_for_each_segment_all(bvl, bio, i)                           \
 160         for (i = 0, bvl = (bio)->bi_io_vec; i < (bio)->bi_vcnt; i++, bvl++)
 161
 162 static inline void bio_advance_iter(struct bio *bio, struct bvec_iter *iter,
 163                                     unsigned bytes)
 164 {
 165         iter->bi_sector += bytes >> 9;
 166
 167         if (bio_no_advance_iter(bio))
 168                 iter->bi_size -= bytes;
 169         else
 170                 bvec_iter_advance(bio->bi_io_vec, iter, bytes);
 171 }
 172
 173 #define __bio_for_each_segment(bvl, bio, iter, start)                   \
 174         for (iter = (start);                                            \
 175              (iter).bi_size &&                                          \
 176                 ((bvl = bio_iter_iovec((bio), (iter))), 1);             \
 177              bio_advance_iter((bio), &(iter), (bvl).bv_len))
 178
 179 #define bio_for_each_segment(bvl, bio, iter)                            \
 180         __bio_for_each_segment(bvl, bio, iter, (bio)->bi_iter)
 181
 182 #define bio_iter_last(bvec, iter) ((iter).bi_size == (bvec).bv_len)
 183
 184 static inline unsigned bio_segments(struct bio *bio)
 185 {
 186         unsigned segs = 0;
 187         struct bio_vec bv;
 188         struct bvec_iter iter;
 189
 190         /*
 191          * We special case discard/write same, because they interpret bi_size
 192          * differently:
 193          */
 194
 195         if (bio_op(bio) == REQ_OP_DISCARD)
 196                 return 1;
 197
 198         if (bio_op(bio) == REQ_OP_SECURE_ERASE)
 199                 return 1;
 200
 201         if (bio_op(bio) == REQ_OP_WRITE_SAME)
 202                 return 1;
 203
 204         bio_for_each_segment(bv, bio, iter)
 205                 segs++;
 206
 207         return segs;
 208 }
 209
 210 /*
 211  * get a reference to a bio, so it won't disappear. the intended use is
 212  * something like:
 213  *
 214  * bio_get(bio);
 215  * submit_bio(rw, bio);
 216  * if (bio->bi_flags ...)
 217  *      do_something
 218  * bio_put(bio);
 219  *
 220  * without the bio_get(), it could potentially complete I/O before submit_bio
 221  * returns. and then bio would be freed memory when if (bio->bi_flags ...)
 222  * runs
 223  */
 224 static inline void bio_get(struct bio *bio)
 225 {
 226         bio->bi_flags |= (1 << BIO_REFFED);
 227         smp_mb__before_atomic();
 228         atomic_inc(&bio->__bi_cnt);
 229 }
 230
 231 static inline void bio_cnt_set(struct bio *bio, unsigned int count)
 232 {
 233         if (count != 1) {
 234                 bio->bi_flags |= (1 << BIO_REFFED);
 235                 smp_mb__before_atomic();
 236         }
 237         atomic_set(&bio->__bi_cnt, count);
 238 }
 239
 240 static inline bool bio_flagged(struct bio *bio, unsigned int bit)
 241 {
 242         return (bio->bi_flags & (1U << bit)) != 0;
 243 }
 244
 245 static inline void bio_set_flag(struct bio *bio, unsigned int bit)
 246 {
 247         bio->bi_flags |= (1U << bit);
 248 }
 249
 250 static inline void bio_clear_flag(struct bio *bio, unsigned int bit)
 251 {
 252         bio->bi_flags &= ~(1U << bit);
 253 }
 254
 255 static inline void bio_get_first_bvec(struct bio *bio, struct bio_vec *bv)
 256 {
 257         *bv = bio_iovec(bio);
 258 }
 259
 260 static inline void bio_get_last_bvec(struct bio *bio, struct bio_vec *bv)
 261 {
 262         struct bvec_iter iter = bio->bi_iter;
 263         int idx;
 264
 265         if (unlikely(!bio_multiple_segments(bio))) {
 266                 *bv = bio_iovec(bio);
 267                 return;
 268         }
 269
 270         bio_advance_iter(bio, &iter, iter.bi_size);
 271
 272         if (!iter.bi_bvec_done)
 273                 idx = iter.bi_idx - 1;
 274         else    /* in the middle of bvec */
 275                 idx = iter.bi_idx;
 276
 277         *bv = bio->bi_io_vec[idx];
 278
 279         /*
 280          * iter.bi_bvec_done records actual length of the last bvec
 281          * if this bio ends in the middle of one io vector
 282          */
 283         if (iter.bi_bvec_done)
 284                 bv->bv_len = iter.bi_bvec_done;
 285 }
 286
 287 enum bip_flags {
 288         BIP_BLOCK_INTEGRITY     = 1 << 0, /* block layer owns integrity data */
 289         BIP_MAPPED_INTEGRITY    = 1 << 1, /* ref tag has been remapped */
 290         BIP_CTRL_NOCHECK        = 1 << 2, /* disable HBA integrity checking */
 291         BIP_DISK_NOCHECK        = 1 << 3, /* disable disk integrity checking */
 292         BIP_IP_CHECKSUM         = 1 << 4, /* IP checksum */
 293 };
 294
 295 /*
 296  * bio integrity payload
 297  */
 298 struct bio_integrity_payload {
 299         struct bio              *bip_bio;       /* parent bio */
 300
 301         struct bvec_iter        bip_iter;
 302
 303         bio_end_io_t            *bip_end_io;    /* saved I/O completion fn */
 304
 305         unsigned short          bip_slab;       /* slab the bip came from */
 306         unsigned short          bip_vcnt;       /* # of integrity bio_vecs */
 307         unsigned short          bip_max_vcnt;   /* integrity bio_vec slots */
 308         unsigned short          bip_flags;      /* control flags */
 309
 310         struct work_struct      bip_work;       /* I/O completion */
 311
 312         struct bio_vec          *bip_vec;
 313         struct bio_vec          bip_inline_vecs[0];/* embedded bvec array */
 314 };
 315
 316 #if defined(CONFIG_BLK_DEV_INTEGRITY)
 317
 318 static inline struct bio_integrity_payload *bio_integrity(struct bio *bio)
 319 {
 320         if (bio->bi_opf & REQ_INTEGRITY)
 321                 return bio->bi_integrity;
 322
 323         return NULL;
 324 }
 325
 326 static inline bool bio_integrity_flagged(struct bio *bio, enum bip_flags flag)
 327 {
 328         struct bio_integrity_payload *bip = bio_integrity(bio);
 329
 330         if (bip)
 331                 return bip->bip_flags & flag;
 332
 333         return false;
 334 }
 335
 336 static inline sector_t bip_get_seed(struct bio_integrity_payload *bip)
 337 {
 338         return bip->bip_iter.bi_sector;
 339 }
 340
 341 static inline void bip_set_seed(struct bio_integrity_payload *bip,
 342                                 sector_t seed)
 343 {
 344         bip->bip_iter.bi_sector = seed;
 345 }
 346
 347 #endif /* CONFIG_BLK_DEV_INTEGRITY */
 348
 349 extern void bio_trim(struct bio *bio, int offset, int size);
 350 extern struct bio *bio_split(struct bio *bio, int sectors,
 351                              gfp_t gfp, struct bio_set *bs);
 352
 353 /**
 354  * bio_next_split - get next @sectors from a bio, splitting if necessary
 355  * @bio:        bio to split
 356  * @sectors:    number of sectors to split from the front of @bio
 357  * @gfp:        gfp mask
 358  * @bs:         bio set to allocate from
 359  *
 360  * Returns a bio representing the next @sectors of @bio - if the bio is smaller
 361  * than @sectors, returns the original bio unchanged.
 362  */
 363 static inline struct bio *bio_next_split(struct bio *bio, int sectors,
 364                                          gfp_t gfp, struct bio_set *bs)
 365 {
 366         if (sectors >= bio_sectors(bio))
 367                 return bio;
 368
 369         return bio_split(bio, sectors, gfp, bs);
 370 }
 371
 372 extern struct bio_set *bioset_create(unsigned int, unsigned int);
 373 extern struct bio_set *bioset_create_nobvec(unsigned int, unsigned int);
 374 extern void bioset_free(struct bio_set *);
 375 extern mempool_t *biovec_create_pool(int pool_entries);
 376
 377 extern struct bio *bio_alloc_bioset(gfp_t, int, struct bio_set *);
 378 extern void bio_put(struct bio *);
 379
 380 extern void __bio_clone_fast(struct bio *, struct bio *);
 381 extern struct bio *bio_clone_fast(struct bio *, gfp_t, struct bio_set *);
 382 extern struct bio *bio_clone_bioset(struct bio *, gfp_t, struct bio_set *bs);
 383
 384 extern struct bio_set *fs_bio_set;
 385
 386 static inline struct bio *bio_alloc(gfp_t gfp_mask, unsigned int nr_iovecs)
 387 {
 388         return bio_alloc_bioset(gfp_mask, nr_iovecs, fs_bio_set);
 389 }
 390
 391 static inline struct bio *bio_clone(struct bio *bio, gfp_t gfp_mask)
 392 {
 393         return bio_clone_bioset(bio, gfp_mask, fs_bio_set);
 394 }
 395
 396 static inline struct bio *bio_kmalloc(gfp_t gfp_mask, unsigned int nr_iovecs)
 397 {
 398         return bio_alloc_bioset(gfp_mask, nr_iovecs, NULL);
 399 }
 400
 401 static inline struct bio *bio_clone_kmalloc(struct bio *bio, gfp_t gfp_mask)
 402 {
 403         return bio_clone_bioset(bio, gfp_mask, NULL);
 404
 405 }
 406
 407 extern blk_qc_t submit_bio(struct bio *);
 408
 409 extern void bio_endio(struct bio *);
 410
 411 static inline void bio_io_error(struct bio *bio)
 412 {
 413         bio->bi_error = -EIO;
 414         bio_endio(bio);
 415 }
 416
 417 struct request_queue;
 418 extern int bio_phys_segments(struct request_queue *, struct bio *);
 419
 420 extern int submit_bio_wait(struct bio *bio);
 421 extern void bio_advance(struct bio *, unsigned);
 422
 423 extern void bio_init(struct bio *bio, struct bio_vec *table,
 424                      unsigned short max_vecs);
 425 extern void bio_reset(struct bio *);
 426 void bio_chain(struct bio *, struct bio *);
 427
 428 extern int bio_add_page(struct bio *, struct page *, unsigned int,unsigned int);
 429 extern int bio_add_pc_page(struct request_queue *, struct bio *, struct page *,
 430                            unsigned int, unsigned int);
 431 int bio_iov_iter_get_pages(struct bio *bio, struct iov_iter *iter);
 432 struct rq_map_data;
 433 extern struct bio *bio_map_user_iov(struct request_queue *,
 434                                     const struct iov_iter *, gfp_t);
 435 extern void bio_unmap_user(struct bio *);
 436 extern struct bio *bio_map_kern(struct request_queue *, void *, unsigned int,
 437                                 gfp_t);
 438 extern struct bio *bio_copy_kern(struct request_queue *, void *, unsigned int,
 439                                  gfp_t, int);
 440 extern void bio_set_pages_dirty(struct bio *bio);
 441 extern void bio_check_pages_dirty(struct bio *bio);
 442
 443 void generic_start_io_acct(int rw, unsigned long sectors,
 444                            struct hd_struct *part);
 445 void generic_end_io_acct(int rw, struct hd_struct *part,
 446                          unsigned long start_time);
 447
 448 #ifndef ARCH_IMPLEMENTS_FLUSH_DCACHE_PAGE
 449 # error "You should define ARCH_IMPLEMENTS_FLUSH_DCACHE_PAGE for your platform"
 450 #endif
 451 #if ARCH_IMPLEMENTS_FLUSH_DCACHE_PAGE
 452 extern void bio_flush_dcache_pages(struct bio *bi);
 453 #else
 454 static inline void bio_flush_dcache_pages(struct bio *bi)
 455 {
 456 }
 457 #endif
 458
 459 extern void bio_copy_data(struct bio *dst, struct bio *src);
 460 extern int bio_alloc_pages(struct bio *bio, gfp_t gfp);
 461 extern void bio_free_pages(struct bio *bio);
 462
 463 extern struct bio *bio_copy_user_iov(struct request_queue *,
 464                                      struct rq_map_data *,
 465                                      const struct iov_iter *,
 466                                      gfp_t);
 467 extern int bio_uncopy_user(struct bio *);
 468 void zero_fill_bio(struct bio *bio);
 469 extern struct bio_vec *bvec_alloc(gfp_t, int, unsigned long *, mempool_t *);
 470 extern void bvec_free(mempool_t *, struct bio_vec *, unsigned int);
 471 extern unsigned int bvec_nr_vecs(unsigned short idx);
 472
 473 #ifdef CONFIG_BLK_CGROUP
 474 int bio_associate_blkcg(struct bio *bio, struct cgroup_subsys_state *blkcg_css);
 475 int bio_associate_current(struct bio *bio);
 476 void bio_disassociate_task(struct bio *bio);
 477 void bio_clone_blkcg_association(struct bio *dst, struct bio *src);
 478 #else   /* CONFIG_BLK_CGROUP */
 479 static inline int bio_associate_blkcg(struct bio *bio,
 480                         struct cgroup_subsys_state *blkcg_css) { return 0; }
 481 static inline int bio_associate_current(struct bio *bio) { return -ENOENT; }
 482 static inline void bio_disassociate_task(struct bio *bio) { }
 483 static inline void bio_clone_blkcg_association(struct bio *dst,
 484                         struct bio *src) { }
 485 #endif  /* CONFIG_BLK_CGROUP */
 486
 487 #ifdef CONFIG_HIGHMEM
 488 /*
 489  * remember never ever reenable interrupts between a bvec_kmap_irq and
 490  * bvec_kunmap_irq!
 491  */
 492 static inline char *bvec_kmap_irq(struct bio_vec *bvec, unsigned long *flags)
 493 {
 494         unsigned long addr;
 495
 496         /*
 497          * might not be a highmem page, but the preempt/irq count
 498          * balancing is a lot nicer this way
 499          */
 500         local_irq_save(*flags);
 501         addr = (unsigned long) kmap_atomic(bvec->bv_page);
 502
 503         BUG_ON(addr & ~PAGE_MASK);
 504
 505         return (char *) addr + bvec->bv_offset;
 506 }
 507
 508 static inline void bvec_kunmap_irq(char *buffer, unsigned long *flags)
 509 {
 510         unsigned long ptr = (unsigned long) buffer & PAGE_MASK;
 511
 512         kunmap_atomic((void *) ptr);
 513         local_irq_restore(*flags);
 514 }
 515
 516 #else
 517 static inline char *bvec_kmap_irq(struct bio_vec *bvec, unsigned long *flags)
 518 {
 519         return page_address(bvec->bv_page) + bvec->bv_offset;
 520 }
 521
 522 static inline void bvec_kunmap_irq(char *buffer, unsigned long *flags)
 523 {
 524         *flags = 0;
 525 }
 526 #endif
 527
 528 static inline char *__bio_kmap_irq(struct bio *bio, struct bvec_iter iter,
 529                                    unsigned long *flags)
 530 {
 531         return bvec_kmap_irq(&bio_iter_iovec(bio, iter), flags);
 532 }
 533 #define __bio_kunmap_irq(buf, flags)    bvec_kunmap_irq(buf, flags)
 534
 535 #define bio_kmap_irq(bio, flags) \
 536         __bio_kmap_irq((bio), (bio)->bi_iter, (flags))
 537 #define bio_kunmap_irq(buf,flags)       __bio_kunmap_irq(buf, flags)
 538
 539 /*
 540  * BIO list management for use by remapping drivers (e.g. DM or MD) and loop.
 541  *
 542  * A bio_list anchors a singly-linked list of bios chained through the bi_next
 543  * member of the bio.  The bio_list also caches the last list member to allow
 544  * fast access to the tail.
 545  */
 546 struct bio_list {
 547         struct bio *head;
 548         struct bio *tail;
 549 };
 550
 551 static inline int bio_list_empty(const struct bio_list *bl)
 552 {
 553         return bl->head == NULL;
 554 }
 555
 556 static inline void bio_list_init(struct bio_list *bl)
 557 {
 558         bl->head = bl->tail = NULL;
 559 }
 560
 561 #define BIO_EMPTY_LIST  { NULL, NULL }
 562
 563 #define bio_list_for_each(bio, bl) \
 564         for (bio = (bl)->head; bio; bio = bio->bi_next)
 565
 566 static inline unsigned bio_list_size(const struct bio_list *bl)
 567 {
 568         unsigned sz = 0;
 569         struct bio *bio;
 570
 571         bio_list_for_each(bio, bl)
 572                 sz++;
 573
 574         return sz;
 575 }
 576
 577 static inline void bio_list_add(struct bio_list *bl, struct bio *bio)
 578 {
 579         bio->bi_next = NULL;
 580
 581         if (bl->tail)
 582                 bl->tail->bi_next = bio;
 583         else
 584                 bl->head = bio;
 585
 586         bl->tail = bio;
 587 }
 588
 589 static inline void bio_list_add_head(struct bio_list *bl, struct bio *bio)
 590 {
 591         bio->bi_next = bl->head;
 592
 593         bl->head = bio;
 594
 595         if (!bl->tail)
 596                 bl->tail = bio;
 597 }
 598
 599 static inline void bio_list_merge(struct bio_list *bl, struct bio_list *bl2)
 600 {
 601         if (!bl2->head)
 602                 return;
 603
 604         if (bl->tail)
 605                 bl->tail->bi_next = bl2->head;
 606         else
 607                 bl->head = bl2->head;
 608
 609         bl->tail = bl2->tail;
 610 }
 611
 612 static inline void bio_list_merge_head(struct bio_list *bl,
 613                                        struct bio_list *bl2)
 614 {
 615         if (!bl2->head)
 616                 return;
 617
 618         if (bl->head)
 619                 bl2->tail->bi_next = bl->head;
 620         else
 621                 bl->tail = bl2->tail;
 622
 623         bl->head = bl2->head;
 624 }
 625
 626 static inline struct bio *bio_list_peek(struct bio_list *bl)
 627 {
 628         return bl->head;
 629 }
 630
 631 static inline struct bio *bio_list_pop(struct bio_list *bl)
 632 {
 633         struct bio *bio = bl->head;
 634
 635         if (bio) {
 636                 bl->head = bl->head->bi_next;
 637                 if (!bl->head)
 638                         bl->tail = NULL;
 639
 640                 bio->bi_next = NULL;
 641         }
 642
 643         return bio;
 644 }
 645
 646 static inline struct bio *bio_list_get(struct bio_list *bl)
 647 {
 648         struct bio *bio = bl->head;
 649
 650         bl->head = bl->tail = NULL;
 651
 652         return bio;
 653 }
 654
 655 /*
 656  * Increment chain count for the bio. Make sure the CHAIN flag update
 657  * is visible before the raised count.
 658  */
 659 static inline void bio_inc_remaining(struct bio *bio)
 660 {
 661         bio_set_flag(bio, BIO_CHAIN);
 662         smp_mb__before_atomic();
 663         atomic_inc(&bio->__bi_remaining);
 664 }
 665
 666 /*
 667  * bio_set is used to allow other portions of the IO system to
 668  * allocate their own private memory pools for bio and iovec structures.
 669  * These memory pools in turn all allocate from the bio_slab
 670  * and the bvec_slabs[].
 671  */
 672 #define BIO_POOL_SIZE 2
 673
 674 struct bio_set {
 675         struct kmem_cache *bio_slab;
 676         unsigned int front_pad;
 677
 678         mempool_t *bio_pool;
 679         mempool_t *bvec_pool;
 680 #if defined(CONFIG_BLK_DEV_INTEGRITY)
 681         mempool_t *bio_integrity_pool;
 682         mempool_t *bvec_integrity_pool;
 683 #endif
 684
 685         /*
 686          * Deadlock avoidance for stacking block drivers: see comments in
 687          * bio_alloc_bioset() for details
 688          */
 689         spinlock_t              rescue_lock;
 690         struct bio_list         rescue_list;
 691         struct work_struct      rescue_work;
 692         struct workqueue_struct *rescue_workqueue;
 693 };
 694
 695 struct biovec_slab {
 696         int nr_vecs;
 697         char *name;
 698         struct kmem_cache *slab;
 699 };
 700
 701 /*
 702  * a small number of entries is fine, not going to be performance critical.
 703  * basically we just need to survive
 704  */
 705 #define BIO_SPLIT_ENTRIES 2
 706
 707 #if defined(CONFIG_BLK_DEV_INTEGRITY)
 708
 709 #define bip_for_each_vec(bvl, bip, iter)                                \
 710         for_each_bvec(bvl, (bip)->bip_vec, iter, (bip)->bip_iter)
 711
 712 #define bio_for_each_integrity_vec(_bvl, _bio, _iter)                   \
 713         for_each_bio(_bio)                                              \
 714                 bip_for_each_vec(_bvl, _bio->bi_integrity, _iter)
 715
 716 extern struct bio_integrity_payload *bio_integrity_alloc(struct bio *, gfp_t, unsigned int);
 717 extern void bio_integrity_free(struct bio *);
 718 extern int bio_integrity_add_page(struct bio *, struct page *, unsigned int, unsigned int);
 719 extern bool bio_integrity_enabled(struct bio *bio);
 720 extern int bio_integrity_prep(struct bio *);
 721 extern void bio_integrity_endio(struct bio *);
 722 extern void bio_integrity_advance(struct bio *, unsigned int);
 723 extern void bio_integrity_trim(struct bio *, unsigned int, unsigned int);
 724 extern int bio_integrity_clone(struct bio *, struct bio *, gfp_t);
 725 extern int bioset_integrity_create(struct bio_set *, int);
 726 extern void bioset_integrity_free(struct bio_set *);
 727 extern void bio_integrity_init(void);
 728
 729 #else /* CONFIG_BLK_DEV_INTEGRITY */
 730
 731 static inline void *bio_integrity(struct bio *bio)
 732 {
 733         return NULL;
 734 }
 735
 736 static inline bool bio_integrity_enabled(struct bio *bio)
 737 {
 738         return false;
 739 }
 740
 741 static inline int bioset_integrity_create(struct bio_set *bs, int pool_size)
 742 {
 743         return 0;
 744 }
 745
 746 static inline void bioset_integrity_free (struct bio_set *bs)
 747 {
 748         return;
 749 }
 750
 751 static inline int bio_integrity_prep(struct bio *bio)
 752 {
 753         return 0;
 754 }
 755
 756 static inline void bio_integrity_free(struct bio *bio)
 757 {
 758         return;
 759 }
 760
 761 static inline int bio_integrity_clone(struct bio *bio, struct bio *bio_src,
 762                                       gfp_t gfp_mask)
 763 {
 764         return 0;
 765 }
 766
 767 static inline void bio_integrity_advance(struct bio *bio,
 768                                          unsigned int bytes_done)
 769 {
 770         return;
 771 }
 772
 773 static inline void bio_integrity_trim(struct bio *bio, unsigned int offset,
 774                                       unsigned int sectors)
 775 {
 776         return;
 777 }
 778
 779 static inline void bio_integrity_init(void)
 780 {
 781         return;
 782 }
 783
 784 static inline bool bio_integrity_flagged(struct bio *bio, enum bip_flags flag)
 785 {
 786         return false;
 787 }
 788
 789 static inline void *bio_integrity_alloc(struct bio * bio, gfp_t gfp,
 790                                                                 unsigned int nr)
 791 {
 792         return ERR_PTR(-EINVAL);
 793 }
 794
 795 static inline int bio_integrity_add_page(struct bio *bio, struct page *page,
 796                                         unsigned int len, unsigned int offset)
 797 {
 798         return 0;
 799 }
 800
 801 #endif /* CONFIG_BLK_DEV_INTEGRITY */
 802
 803 #endif /* CONFIG_BLOCK */
 804 #endif /* __LINUX_BIO_H */