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             bio_op(bio) != REQ_OP_WRITE_ZEROES)
  81                 return true;
  82
  83         return false;
  84 }
  85
  86 static inline bool bio_no_advance_iter(struct bio *bio)
  87 {
  88         return bio_op(bio) == REQ_OP_DISCARD ||
  89                bio_op(bio) == REQ_OP_SECURE_ERASE ||
  90                bio_op(bio) == REQ_OP_WRITE_SAME ||
  91                bio_op(bio) == REQ_OP_WRITE_ZEROES;
  92 }
  93
  94 static inline bool bio_mergeable(struct bio *bio)
  95 {
  96         if (bio->bi_opf & REQ_NOMERGE_FLAGS)
  97                 return false;
  98
  99         return true;
 100 }
 101
 102 static inline unsigned int bio_cur_bytes(struct bio *bio)
 103 {
 104         if (bio_has_data(bio))
 105                 return bio_iovec(bio).bv_len;
 106         else /* dataless requests such as discard */
 107                 return bio->bi_iter.bi_size;
 108 }
 109
 110 static inline void *bio_data(struct bio *bio)
 111 {
 112         if (bio_has_data(bio))
 113                 return page_address(bio_page(bio)) + bio_offset(bio);
 114
 115         return NULL;
 116 }
 117
 118 /*
 119  * will die
 120  */
 121 #define bvec_to_phys(bv)        (page_to_phys((bv)->bv_page) + (unsigned long) (bv)->bv_offset)
 122
 123 /*
 124  * queues that have highmem support enabled may still need to revert to
 125  * PIO transfers occasionally and thus map high pages temporarily. For
 126  * permanent PIO fall back, user is probably better off disabling highmem
 127  * I/O completely on that queue (see ide-dma for example)
 128  */
 129 #define __bio_kmap_atomic(bio, iter)                            \
 130         (kmap_atomic(bio_iter_iovec((bio), (iter)).bv_page) +   \
 131                 bio_iter_iovec((bio), (iter)).bv_offset)
 132
 133 #define __bio_kunmap_atomic(addr)       kunmap_atomic(addr)
 134
 135 /*
 136  * merge helpers etc
 137  */
 138
 139 /* Default implementation of BIOVEC_PHYS_MERGEABLE */
 140 #define __BIOVEC_PHYS_MERGEABLE(vec1, vec2)     \
 141         ((bvec_to_phys((vec1)) + (vec1)->bv_len) == bvec_to_phys((vec2)))
 142
 143 /*
 144  * allow arch override, for eg virtualized architectures (put in asm/io.h)
 145  */
 146 #ifndef BIOVEC_PHYS_MERGEABLE
 147 #define BIOVEC_PHYS_MERGEABLE(vec1, vec2)       \
 148         __BIOVEC_PHYS_MERGEABLE(vec1, vec2)
 149 #endif
 150
 151 #define __BIO_SEG_BOUNDARY(addr1, addr2, mask) \
 152         (((addr1) | (mask)) == (((addr2) - 1) | (mask)))
 153 #define BIOVEC_SEG_BOUNDARY(q, b1, b2) \
 154         __BIO_SEG_BOUNDARY(bvec_to_phys((b1)), bvec_to_phys((b2)) + (b2)->bv_len, queue_segment_boundary((q)))
 155
 156 /*
 157  * drivers should _never_ use the all version - the bio may have been split
 158  * before it got to the driver and the driver won't own all of it
 159  */
 160 #define bio_for_each_segment_all(bvl, bio, i)                           \
 161         for (i = 0, bvl = (bio)->bi_io_vec; i < (bio)->bi_vcnt; i++, bvl++)
 162
 163 static inline void bio_advance_iter(struct bio *bio, struct bvec_iter *iter,
 164                                     unsigned bytes)
 165 {
 166         iter->bi_sector += bytes >> 9;
 167
 168         if (bio_no_advance_iter(bio)) {
 169                 iter->bi_size -= bytes;
 170                 iter->bi_done += bytes;
 171         } else {
 172                 bvec_iter_advance(bio->bi_io_vec, iter, bytes);
 173                 /* TODO: It is reasonable to complete bio with error here. */
 174         }
 175 }
 176
 177 static inline bool bio_rewind_iter(struct bio *bio, struct bvec_iter *iter,
 178                 unsigned int bytes)
 179 {
 180         iter->bi_sector -= bytes >> 9;
 181
 182         if (bio_no_advance_iter(bio)) {
 183                 iter->bi_size += bytes;
 184                 iter->bi_done -= bytes;
 185                 return true;
 186         }
 187
 188         return bvec_iter_rewind(bio->bi_io_vec, iter, bytes);
 189 }
 190
 191 #define __bio_for_each_segment(bvl, bio, iter, start)                   \
 192         for (iter = (start);                                            \
 193              (iter).bi_size &&                                          \
 194                 ((bvl = bio_iter_iovec((bio), (iter))), 1);             \
 195              bio_advance_iter((bio), &(iter), (bvl).bv_len))
 196
 197 #define bio_for_each_segment(bvl, bio, iter)                            \
 198         __bio_for_each_segment(bvl, bio, iter, (bio)->bi_iter)
 199
 200 #define bio_iter_last(bvec, iter) ((iter).bi_size == (bvec).bv_len)
 201
 202 static inline unsigned bio_segments(struct bio *bio)
 203 {
 204         unsigned segs = 0;
 205         struct bio_vec bv;
 206         struct bvec_iter iter;
 207
 208         /*
 209          * We special case discard/write same/write zeroes, because they
 210          * interpret bi_size differently:
 211          */
 212
 213         switch (bio_op(bio)) {
 214         case REQ_OP_DISCARD:
 215         case REQ_OP_SECURE_ERASE:
 216         case REQ_OP_WRITE_ZEROES:
 217                 return 0;
 218         case REQ_OP_WRITE_SAME:
 219                 return 1;
 220         default:
 221                 break;
 222         }
 223
 224         bio_for_each_segment(bv, bio, iter)
 225                 segs++;
 226
 227         return segs;
 228 }
 229
 230 /*
 231  * get a reference to a bio, so it won't disappear. the intended use is
 232  * something like:
 233  *
 234  * bio_get(bio);
 235  * submit_bio(rw, bio);
 236  * if (bio->bi_flags ...)
 237  *      do_something
 238  * bio_put(bio);
 239  *
 240  * without the bio_get(), it could potentially complete I/O before submit_bio
 241  * returns. and then bio would be freed memory when if (bio->bi_flags ...)
 242  * runs
 243  */
 244 static inline void bio_get(struct bio *bio)
 245 {
 246         bio->bi_flags |= (1 << BIO_REFFED);
 247         smp_mb__before_atomic();
 248         atomic_inc(&bio->__bi_cnt);
 249 }
 250
 251 static inline void bio_cnt_set(struct bio *bio, unsigned int count)
 252 {
 253         if (count != 1) {
 254                 bio->bi_flags |= (1 << BIO_REFFED);
 255                 smp_mb__before_atomic();
 256         }
 257         atomic_set(&bio->__bi_cnt, count);
 258 }
 259
 260 static inline bool bio_flagged(struct bio *bio, unsigned int bit)
 261 {
 262         return (bio->bi_flags & (1U << bit)) != 0;
 263 }
 264
 265 static inline void bio_set_flag(struct bio *bio, unsigned int bit)
 266 {
 267         bio->bi_flags |= (1U << bit);
 268 }
 269
 270 static inline void bio_clear_flag(struct bio *bio, unsigned int bit)
 271 {
 272         bio->bi_flags &= ~(1U << bit);
 273 }
 274
 275 static inline void bio_get_first_bvec(struct bio *bio, struct bio_vec *bv)
 276 {
 277         *bv = bio_iovec(bio);
 278 }
 279
 280 static inline void bio_get_last_bvec(struct bio *bio, struct bio_vec *bv)
 281 {
 282         struct bvec_iter iter = bio->bi_iter;
 283         int idx;
 284
 285         if (unlikely(!bio_multiple_segments(bio))) {
 286                 *bv = bio_iovec(bio);
 287                 return;
 288         }
 289
 290         bio_advance_iter(bio, &iter, iter.bi_size);
 291
 292         if (!iter.bi_bvec_done)
 293                 idx = iter.bi_idx - 1;
 294         else    /* in the middle of bvec */
 295                 idx = iter.bi_idx;
 296
 297         *bv = bio->bi_io_vec[idx];
 298
 299         /*
 300          * iter.bi_bvec_done records actual length of the last bvec
 301          * if this bio ends in the middle of one io vector
 302          */
 303         if (iter.bi_bvec_done)
 304                 bv->bv_len = iter.bi_bvec_done;
 305 }
 306
 307 enum bip_flags {
 308         BIP_BLOCK_INTEGRITY     = 1 << 0, /* block layer owns integrity data */
 309         BIP_MAPPED_INTEGRITY    = 1 << 1, /* ref tag has been remapped */
 310         BIP_CTRL_NOCHECK        = 1 << 2, /* disable HBA integrity checking */
 311         BIP_DISK_NOCHECK        = 1 << 3, /* disable disk integrity checking */
 312         BIP_IP_CHECKSUM         = 1 << 4, /* IP checksum */
 313 };
 314
 315 /*
 316  * bio integrity payload
 317  */
 318 struct bio_integrity_payload {
 319         struct bio              *bip_bio;       /* parent bio */
 320
 321         struct bvec_iter        bip_iter;
 322
 323         unsigned short          bip_slab;       /* slab the bip came from */
 324         unsigned short          bip_vcnt;       /* # of integrity bio_vecs */
 325         unsigned short          bip_max_vcnt;   /* integrity bio_vec slots */
 326         unsigned short          bip_flags;      /* control flags */
 327
 328         struct work_struct      bip_work;       /* I/O completion */
 329
 330         struct bio_vec          *bip_vec;
 331         struct bio_vec          bip_inline_vecs[0];/* embedded bvec array */
 332 };
 333
 334 #if defined(CONFIG_BLK_DEV_INTEGRITY)
 335
 336 static inline struct bio_integrity_payload *bio_integrity(struct bio *bio)
 337 {
 338         if (bio->bi_opf & REQ_INTEGRITY)
 339                 return bio->bi_integrity;
 340
 341         return NULL;
 342 }
 343
 344 static inline bool bio_integrity_flagged(struct bio *bio, enum bip_flags flag)
 345 {
 346         struct bio_integrity_payload *bip = bio_integrity(bio);
 347
 348         if (bip)
 349                 return bip->bip_flags & flag;
 350
 351         return false;
 352 }
 353
 354 static inline sector_t bip_get_seed(struct bio_integrity_payload *bip)
 355 {
 356         return bip->bip_iter.bi_sector;
 357 }
 358
 359 static inline void bip_set_seed(struct bio_integrity_payload *bip,
 360                                 sector_t seed)
 361 {
 362         bip->bip_iter.bi_sector = seed;
 363 }
 364
 365 #endif /* CONFIG_BLK_DEV_INTEGRITY */
 366
 367 extern void bio_trim(struct bio *bio, int offset, int size);
 368 extern struct bio *bio_split(struct bio *bio, int sectors,
 369                              gfp_t gfp, struct bio_set *bs);
 370
 371 /**
 372  * bio_next_split - get next @sectors from a bio, splitting if necessary
 373  * @bio:        bio to split
 374  * @sectors:    number of sectors to split from the front of @bio
 375  * @gfp:        gfp mask
 376  * @bs:         bio set to allocate from
 377  *
 378  * Returns a bio representing the next @sectors of @bio - if the bio is smaller
 379  * than @sectors, returns the original bio unchanged.
 380  */
 381 static inline struct bio *bio_next_split(struct bio *bio, int sectors,
 382                                          gfp_t gfp, struct bio_set *bs)
 383 {
 384         if (sectors >= bio_sectors(bio))
 385                 return bio;
 386
 387         return bio_split(bio, sectors, gfp, bs);
 388 }
 389
 390 extern struct bio_set *bioset_create(unsigned int, unsigned int, int flags);
 391 enum {
 392         BIOSET_NEED_BVECS = BIT(0),
 393         BIOSET_NEED_RESCUER = BIT(1),
 394 };
 395 extern void bioset_free(struct bio_set *);
 396 extern mempool_t *biovec_create_pool(int pool_entries);
 397
 398 extern struct bio *bio_alloc_bioset(gfp_t, unsigned int, struct bio_set *);
 399 extern void bio_put(struct bio *);
 400
 401 extern void __bio_clone_fast(struct bio *, struct bio *);
 402 extern struct bio *bio_clone_fast(struct bio *, gfp_t, struct bio_set *);
 403 extern struct bio *bio_clone_bioset(struct bio *, gfp_t, struct bio_set *bs);
 404
 405 extern struct bio_set *fs_bio_set;
 406
 407 static inline struct bio *bio_alloc(gfp_t gfp_mask, unsigned int nr_iovecs)
 408 {
 409         return bio_alloc_bioset(gfp_mask, nr_iovecs, fs_bio_set);
 410 }
 411
 412 static inline struct bio *bio_kmalloc(gfp_t gfp_mask, unsigned int nr_iovecs)
 413 {
 414         return bio_alloc_bioset(gfp_mask, nr_iovecs, NULL);
 415 }
 416
 417 static inline struct bio *bio_clone_kmalloc(struct bio *bio, gfp_t gfp_mask)
 418 {
 419         return bio_clone_bioset(bio, gfp_mask, NULL);
 420
 421 }
 422
 423 extern blk_qc_t submit_bio(struct bio *);
 424
 425 extern void bio_endio(struct bio *);
 426
 427 static inline void bio_io_error(struct bio *bio)
 428 {
 429         bio->bi_status = BLK_STS_IOERR;
 430         bio_endio(bio);
 431 }
 432
 433 static inline void bio_wouldblock_error(struct bio *bio)
 434 {
 435         bio->bi_status = BLK_STS_AGAIN;
 436         bio_endio(bio);
 437 }
 438
 439 struct request_queue;
 440 extern int bio_phys_segments(struct request_queue *, struct bio *);
 441
 442 extern int submit_bio_wait(struct bio *bio);
 443 extern void bio_advance(struct bio *, unsigned);
 444
 445 extern void bio_init(struct bio *bio, struct bio_vec *table,
 446                      unsigned short max_vecs);
 447 extern void bio_uninit(struct bio *);
 448 extern void bio_reset(struct bio *);
 449 void bio_chain(struct bio *, struct bio *);
 450
 451 extern int bio_add_page(struct bio *, struct page *, unsigned int,unsigned int);
 452 extern int bio_add_pc_page(struct request_queue *, struct bio *, struct page *,
 453                            unsigned int, unsigned int);
 454 int bio_iov_iter_get_pages(struct bio *bio, struct iov_iter *iter);
 455 struct rq_map_data;
 456 extern struct bio *bio_map_user_iov(struct request_queue *,
 457                                     const struct iov_iter *, gfp_t);
 458 extern void bio_unmap_user(struct bio *);
 459 extern struct bio *bio_map_kern(struct request_queue *, void *, unsigned int,
 460                                 gfp_t);
 461 extern struct bio *bio_copy_kern(struct request_queue *, void *, unsigned int,
 462                                  gfp_t, int);
 463 extern void bio_set_pages_dirty(struct bio *bio);
 464 extern void bio_check_pages_dirty(struct bio *bio);
 465
 466 void generic_start_io_acct(int rw, unsigned long sectors,
 467                            struct hd_struct *part);
 468 void generic_end_io_acct(int rw, struct hd_struct *part,
 469                          unsigned long start_time);
 470
 471 #ifndef ARCH_IMPLEMENTS_FLUSH_DCACHE_PAGE
 472 # error "You should define ARCH_IMPLEMENTS_FLUSH_DCACHE_PAGE for your platform"
 473 #endif
 474 #if ARCH_IMPLEMENTS_FLUSH_DCACHE_PAGE
 475 extern void bio_flush_dcache_pages(struct bio *bi);
 476 #else
 477 static inline void bio_flush_dcache_pages(struct bio *bi)
 478 {
 479 }
 480 #endif
 481
 482 extern void bio_copy_data(struct bio *dst, struct bio *src);
 483 extern int bio_alloc_pages(struct bio *bio, gfp_t gfp);
 484 extern void bio_free_pages(struct bio *bio);
 485
 486 extern struct bio *bio_copy_user_iov(struct request_queue *,
 487                                      struct rq_map_data *,
 488                                      const struct iov_iter *,
 489                                      gfp_t);
 490 extern int bio_uncopy_user(struct bio *);
 491 void zero_fill_bio(struct bio *bio);
 492 extern struct bio_vec *bvec_alloc(gfp_t, int, unsigned long *, mempool_t *);
 493 extern void bvec_free(mempool_t *, struct bio_vec *, unsigned int);
 494 extern unsigned int bvec_nr_vecs(unsigned short idx);
 495
 496 #ifdef CONFIG_BLK_CGROUP
 497 int bio_associate_blkcg(struct bio *bio, struct cgroup_subsys_state *blkcg_css);
 498 int bio_associate_current(struct bio *bio);
 499 void bio_disassociate_task(struct bio *bio);
 500 void bio_clone_blkcg_association(struct bio *dst, struct bio *src);
 501 #else   /* CONFIG_BLK_CGROUP */
 502 static inline int bio_associate_blkcg(struct bio *bio,
 503                         struct cgroup_subsys_state *blkcg_css) { return 0; }
 504 static inline int bio_associate_current(struct bio *bio) { return -ENOENT; }
 505 static inline void bio_disassociate_task(struct bio *bio) { }
 506 static inline void bio_clone_blkcg_association(struct bio *dst,
 507                         struct bio *src) { }
 508 #endif  /* CONFIG_BLK_CGROUP */
 509
 510 #ifdef CONFIG_HIGHMEM
 511 /*
 512  * remember never ever reenable interrupts between a bvec_kmap_irq and
 513  * bvec_kunmap_irq!
 514  */
 515 static inline char *bvec_kmap_irq(struct bio_vec *bvec, unsigned long *flags)
 516 {
 517         unsigned long addr;
 518
 519         /*
 520          * might not be a highmem page, but the preempt/irq count
 521          * balancing is a lot nicer this way
 522          */
 523         local_irq_save(*flags);
 524         addr = (unsigned long) kmap_atomic(bvec->bv_page);
 525
 526         BUG_ON(addr & ~PAGE_MASK);
 527
 528         return (char *) addr + bvec->bv_offset;
 529 }
 530
 531 static inline void bvec_kunmap_irq(char *buffer, unsigned long *flags)
 532 {
 533         unsigned long ptr = (unsigned long) buffer & PAGE_MASK;
 534
 535         kunmap_atomic((void *) ptr);
 536         local_irq_restore(*flags);
 537 }
 538
 539 #else
 540 static inline char *bvec_kmap_irq(struct bio_vec *bvec, unsigned long *flags)
 541 {
 542         return page_address(bvec->bv_page) + bvec->bv_offset;
 543 }
 544
 545 static inline void bvec_kunmap_irq(char *buffer, unsigned long *flags)
 546 {
 547         *flags = 0;
 548 }
 549 #endif
 550
 551 static inline char *__bio_kmap_irq(struct bio *bio, struct bvec_iter iter,
 552                                    unsigned long *flags)
 553 {
 554         return bvec_kmap_irq(&bio_iter_iovec(bio, iter), flags);
 555 }
 556 #define __bio_kunmap_irq(buf, flags)    bvec_kunmap_irq(buf, flags)
 557
 558 #define bio_kmap_irq(bio, flags) \
 559         __bio_kmap_irq((bio), (bio)->bi_iter, (flags))
 560 #define bio_kunmap_irq(buf,flags)       __bio_kunmap_irq(buf, flags)
 561
 562 /*
 563  * BIO list management for use by remapping drivers (e.g. DM or MD) and loop.
 564  *
 565  * A bio_list anchors a singly-linked list of bios chained through the bi_next
 566  * member of the bio.  The bio_list also caches the last list member to allow
 567  * fast access to the tail.
 568  */
 569 struct bio_list {
 570         struct bio *head;
 571         struct bio *tail;
 572 };
 573
 574 static inline int bio_list_empty(const struct bio_list *bl)
 575 {
 576         return bl->head == NULL;
 577 }
 578
 579 static inline void bio_list_init(struct bio_list *bl)
 580 {
 581         bl->head = bl->tail = NULL;
 582 }
 583
 584 #define BIO_EMPTY_LIST  { NULL, NULL }
 585
 586 #define bio_list_for_each(bio, bl) \
 587         for (bio = (bl)->head; bio; bio = bio->bi_next)
 588
 589 static inline unsigned bio_list_size(const struct bio_list *bl)
 590 {
 591         unsigned sz = 0;
 592         struct bio *bio;
 593
 594         bio_list_for_each(bio, bl)
 595                 sz++;
 596
 597         return sz;
 598 }
 599
 600 static inline void bio_list_add(struct bio_list *bl, struct bio *bio)
 601 {
 602         bio->bi_next = NULL;
 603
 604         if (bl->tail)
 605                 bl->tail->bi_next = bio;
 606         else
 607                 bl->head = bio;
 608
 609         bl->tail = bio;
 610 }
 611
 612 static inline void bio_list_add_head(struct bio_list *bl, struct bio *bio)
 613 {
 614         bio->bi_next = bl->head;
 615
 616         bl->head = bio;
 617
 618         if (!bl->tail)
 619                 bl->tail = bio;
 620 }
 621
 622 static inline void bio_list_merge(struct bio_list *bl, struct bio_list *bl2)
 623 {
 624         if (!bl2->head)
 625                 return;
 626
 627         if (bl->tail)
 628                 bl->tail->bi_next = bl2->head;
 629         else
 630                 bl->head = bl2->head;
 631
 632         bl->tail = bl2->tail;
 633 }
 634
 635 static inline void bio_list_merge_head(struct bio_list *bl,
 636                                        struct bio_list *bl2)
 637 {
 638         if (!bl2->head)
 639                 return;
 640
 641         if (bl->head)
 642                 bl2->tail->bi_next = bl->head;
 643         else
 644                 bl->tail = bl2->tail;
 645
 646         bl->head = bl2->head;
 647 }
 648
 649 static inline struct bio *bio_list_peek(struct bio_list *bl)
 650 {
 651         return bl->head;
 652 }
 653
 654 static inline struct bio *bio_list_pop(struct bio_list *bl)
 655 {
 656         struct bio *bio = bl->head;
 657
 658         if (bio) {
 659                 bl->head = bl->head->bi_next;
 660                 if (!bl->head)
 661                         bl->tail = NULL;
 662
 663                 bio->bi_next = NULL;
 664         }
 665
 666         return bio;
 667 }
 668
 669 static inline struct bio *bio_list_get(struct bio_list *bl)
 670 {
 671         struct bio *bio = bl->head;
 672
 673         bl->head = bl->tail = NULL;
 674
 675         return bio;
 676 }
 677
 678 /*
 679  * Increment chain count for the bio. Make sure the CHAIN flag update
 680  * is visible before the raised count.
 681  */
 682 static inline void bio_inc_remaining(struct bio *bio)
 683 {
 684         bio_set_flag(bio, BIO_CHAIN);
 685         smp_mb__before_atomic();
 686         atomic_inc(&bio->__bi_remaining);
 687 }
 688
 689 /*
 690  * bio_set is used to allow other portions of the IO system to
 691  * allocate their own private memory pools for bio and iovec structures.
 692  * These memory pools in turn all allocate from the bio_slab
 693  * and the bvec_slabs[].
 694  */
 695 #define BIO_POOL_SIZE 2
 696
 697 struct bio_set {
 698         struct kmem_cache *bio_slab;
 699         unsigned int front_pad;
 700
 701         mempool_t *bio_pool;
 702         mempool_t *bvec_pool;
 703 #if defined(CONFIG_BLK_DEV_INTEGRITY)
 704         mempool_t *bio_integrity_pool;
 705         mempool_t *bvec_integrity_pool;
 706 #endif
 707
 708         /*
 709          * Deadlock avoidance for stacking block drivers: see comments in
 710          * bio_alloc_bioset() for details
 711          */
 712         spinlock_t              rescue_lock;
 713         struct bio_list         rescue_list;
 714         struct work_struct      rescue_work;
 715         struct workqueue_struct *rescue_workqueue;
 716 };
 717
 718 struct biovec_slab {
 719         int nr_vecs;
 720         char *name;
 721         struct kmem_cache *slab;
 722 };
 723
 724 /*
 725  * a small number of entries is fine, not going to be performance critical.
 726  * basically we just need to survive
 727  */
 728 #define BIO_SPLIT_ENTRIES 2
 729
 730 #if defined(CONFIG_BLK_DEV_INTEGRITY)
 731
 732 #define bip_for_each_vec(bvl, bip, iter)                                \
 733         for_each_bvec(bvl, (bip)->bip_vec, iter, (bip)->bip_iter)
 734
 735 #define bio_for_each_integrity_vec(_bvl, _bio, _iter)                   \
 736         for_each_bio(_bio)                                              \
 737                 bip_for_each_vec(_bvl, _bio->bi_integrity, _iter)
 738
 739 extern struct bio_integrity_payload *bio_integrity_alloc(struct bio *, gfp_t, unsigned int);
 740 extern int bio_integrity_add_page(struct bio *, struct page *, unsigned int, unsigned int);
 741 extern bool bio_integrity_prep(struct bio *);
 742 extern void bio_integrity_advance(struct bio *, unsigned int);
 743 extern void bio_integrity_trim(struct bio *);
 744 extern int bio_integrity_clone(struct bio *, struct bio *, gfp_t);
 745 extern int bioset_integrity_create(struct bio_set *, int);
 746 extern void bioset_integrity_free(struct bio_set *);
 747 extern void bio_integrity_init(void);
 748
 749 #else /* CONFIG_BLK_DEV_INTEGRITY */
 750
 751 static inline void *bio_integrity(struct bio *bio)
 752 {
 753         return NULL;
 754 }
 755
 756 static inline int bioset_integrity_create(struct bio_set *bs, int pool_size)
 757 {
 758         return 0;
 759 }
 760
 761 static inline void bioset_integrity_free (struct bio_set *bs)
 762 {
 763         return;
 764 }
 765
 766 static inline bool bio_integrity_prep(struct bio *bio)
 767 {
 768         return true;
 769 }
 770
 771 static inline int bio_integrity_clone(struct bio *bio, struct bio *bio_src,
 772                                       gfp_t gfp_mask)
 773 {
 774         return 0;
 775 }
 776
 777 static inline void bio_integrity_advance(struct bio *bio,
 778                                          unsigned int bytes_done)
 779 {
 780         return;
 781 }
 782
 783 static inline void bio_integrity_trim(struct bio *bio)
 784 {
 785         return;
 786 }
 787
 788 static inline void bio_integrity_init(void)
 789 {
 790         return;
 791 }
 792
 793 static inline bool bio_integrity_flagged(struct bio *bio, enum bip_flags flag)
 794 {
 795         return false;
 796 }
 797
 798 static inline void *bio_integrity_alloc(struct bio * bio, gfp_t gfp,
 799                                                                 unsigned int nr)
 800 {
 801         return ERR_PTR(-EINVAL);
 802 }
 803
 804 static inline int bio_integrity_add_page(struct bio *bio, struct page *page,
 805                                         unsigned int len, unsigned int offset)
 806 {
 807         return 0;
 808 }
 809
 810 #endif /* CONFIG_BLK_DEV_INTEGRITY */
 811
 812 #endif /* CONFIG_BLOCK */
 813 #endif /* __LINUX_BIO_H */