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 #ifdef CONFIG_THP_SWAP
  42 #if HPAGE_PMD_NR > 256
  43 #define BIO_MAX_PAGES           HPAGE_PMD_NR
  44 #else
  45 #define BIO_MAX_PAGES           256
  46 #endif
  47 #else
  48 #define BIO_MAX_PAGES           256
  49 #endif
  50
  51 #define bio_prio(bio)                   (bio)->bi_ioprio
  52 #define bio_set_prio(bio, prio)         ((bio)->bi_ioprio = prio)
  53
  54 #define bio_iter_iovec(bio, iter)                               \
  55         bvec_iter_bvec((bio)->bi_io_vec, (iter))
  56
  57 #define bio_iter_page(bio, iter)                                \
  58         bvec_iter_page((bio)->bi_io_vec, (iter))
  59 #define bio_iter_len(bio, iter)                                 \
  60         bvec_iter_len((bio)->bi_io_vec, (iter))
  61 #define bio_iter_offset(bio, iter)                              \
  62         bvec_iter_offset((bio)->bi_io_vec, (iter))
  63
  64 #define bio_page(bio)           bio_iter_page((bio), (bio)->bi_iter)
  65 #define bio_offset(bio)         bio_iter_offset((bio), (bio)->bi_iter)
  66 #define bio_iovec(bio)          bio_iter_iovec((bio), (bio)->bi_iter)
  67
  68 #define bio_multiple_segments(bio)                              \
  69         ((bio)->bi_iter.bi_size != bio_iovec(bio).bv_len)
  70 #define bio_sectors(bio)        ((bio)->bi_iter.bi_size >> 9)
  71 #define bio_end_sector(bio)     ((bio)->bi_iter.bi_sector + bio_sectors((bio)))
  72
  73 /*
  74  * Return the data direction, READ or WRITE.
  75  */
  76 #define bio_data_dir(bio) \
  77         (op_is_write(bio_op(bio)) ? WRITE : READ)
  78
  79 /*
  80  * Check whether this bio carries any data or not. A NULL bio is allowed.
  81  */
  82 static inline bool bio_has_data(struct bio *bio)
  83 {
  84         if (bio &&
  85             bio->bi_iter.bi_size &&
  86             bio_op(bio) != REQ_OP_DISCARD &&
  87             bio_op(bio) != REQ_OP_SECURE_ERASE &&
  88             bio_op(bio) != REQ_OP_WRITE_ZEROES)
  89                 return true;
  90
  91         return false;
  92 }
  93
  94 static inline bool bio_no_advance_iter(struct bio *bio)
  95 {
  96         return bio_op(bio) == REQ_OP_DISCARD ||
  97                bio_op(bio) == REQ_OP_SECURE_ERASE ||
  98                bio_op(bio) == REQ_OP_WRITE_SAME ||
  99                bio_op(bio) == REQ_OP_WRITE_ZEROES;
 100 }
 101
 102 static inline bool bio_mergeable(struct bio *bio)
 103 {
 104         if (bio->bi_opf & REQ_NOMERGE_FLAGS)
 105                 return false;
 106
 107         return true;
 108 }
 109
 110 static inline unsigned int bio_cur_bytes(struct bio *bio)
 111 {
 112         if (bio_has_data(bio))
 113                 return bio_iovec(bio).bv_len;
 114         else /* dataless requests such as discard */
 115                 return bio->bi_iter.bi_size;
 116 }
 117
 118 static inline void *bio_data(struct bio *bio)
 119 {
 120         if (bio_has_data(bio))
 121                 return page_address(bio_page(bio)) + bio_offset(bio);
 122
 123         return NULL;
 124 }
 125
 126 /*
 127  * will die
 128  */
 129 #define bvec_to_phys(bv)        (page_to_phys((bv)->bv_page) + (unsigned long) (bv)->bv_offset)
 130
 131 /*
 132  * merge helpers etc
 133  */
 134
 135 /* Default implementation of BIOVEC_PHYS_MERGEABLE */
 136 #define __BIOVEC_PHYS_MERGEABLE(vec1, vec2)     \
 137         ((bvec_to_phys((vec1)) + (vec1)->bv_len) == bvec_to_phys((vec2)))
 138
 139 /*
 140  * allow arch override, for eg virtualized architectures (put in asm/io.h)
 141  */
 142 #ifndef BIOVEC_PHYS_MERGEABLE
 143 #define BIOVEC_PHYS_MERGEABLE(vec1, vec2)       \
 144         __BIOVEC_PHYS_MERGEABLE(vec1, vec2)
 145 #endif
 146
 147 #define __BIO_SEG_BOUNDARY(addr1, addr2, mask) \
 148         (((addr1) | (mask)) == (((addr2) - 1) | (mask)))
 149 #define BIOVEC_SEG_BOUNDARY(q, b1, b2) \
 150         __BIO_SEG_BOUNDARY(bvec_to_phys((b1)), bvec_to_phys((b2)) + (b2)->bv_len, queue_segment_boundary((q)))
 151
 152 /*
 153  * drivers should _never_ use the all version - the bio may have been split
 154  * before it got to the driver and the driver won't own all of it
 155  */
 156 #define bio_for_each_segment_all(bvl, bio, i)                           \
 157         for (i = 0, bvl = (bio)->bi_io_vec; i < (bio)->bi_vcnt; i++, bvl++)
 158
 159 static inline void bio_advance_iter(struct bio *bio, struct bvec_iter *iter,
 160                                     unsigned bytes)
 161 {
 162         iter->bi_sector += bytes >> 9;
 163
 164         if (bio_no_advance_iter(bio)) {
 165                 iter->bi_size -= bytes;
 166                 iter->bi_done += bytes;
 167         } else {
 168                 bvec_iter_advance(bio->bi_io_vec, iter, bytes);
 169                 /* TODO: It is reasonable to complete bio with error here. */
 170         }
 171 }
 172
 173 static inline bool bio_rewind_iter(struct bio *bio, struct bvec_iter *iter,
 174                 unsigned int bytes)
 175 {
 176         iter->bi_sector -= bytes >> 9;
 177
 178         if (bio_no_advance_iter(bio)) {
 179                 iter->bi_size += bytes;
 180                 iter->bi_done -= bytes;
 181                 return true;
 182         }
 183
 184         return bvec_iter_rewind(bio->bi_io_vec, iter, bytes);
 185 }
 186
 187 #define __bio_for_each_segment(bvl, bio, iter, start)                   \
 188         for (iter = (start);                                            \
 189              (iter).bi_size &&                                          \
 190                 ((bvl = bio_iter_iovec((bio), (iter))), 1);             \
 191              bio_advance_iter((bio), &(iter), (bvl).bv_len))
 192
 193 #define bio_for_each_segment(bvl, bio, iter)                            \
 194         __bio_for_each_segment(bvl, bio, iter, (bio)->bi_iter)
 195
 196 #define bio_iter_last(bvec, iter) ((iter).bi_size == (bvec).bv_len)
 197
 198 static inline unsigned bio_segments(struct bio *bio)
 199 {
 200         unsigned segs = 0;
 201         struct bio_vec bv;
 202         struct bvec_iter iter;
 203
 204         /*
 205          * We special case discard/write same/write zeroes, because they
 206          * interpret bi_size differently:
 207          */
 208
 209         switch (bio_op(bio)) {
 210         case REQ_OP_DISCARD:
 211         case REQ_OP_SECURE_ERASE:
 212         case REQ_OP_WRITE_ZEROES:
 213                 return 0;
 214         case REQ_OP_WRITE_SAME:
 215                 return 1;
 216         default:
 217                 break;
 218         }
 219
 220         bio_for_each_segment(bv, bio, iter)
 221                 segs++;
 222
 223         return segs;
 224 }
 225
 226 /*
 227  * get a reference to a bio, so it won't disappear. the intended use is
 228  * something like:
 229  *
 230  * bio_get(bio);
 231  * submit_bio(rw, bio);
 232  * if (bio->bi_flags ...)
 233  *      do_something
 234  * bio_put(bio);
 235  *
 236  * without the bio_get(), it could potentially complete I/O before submit_bio
 237  * returns. and then bio would be freed memory when if (bio->bi_flags ...)
 238  * runs
 239  */
 240 static inline void bio_get(struct bio *bio)
 241 {
 242         bio->bi_flags |= (1 << BIO_REFFED);
 243         smp_mb__before_atomic();
 244         atomic_inc(&bio->__bi_cnt);
 245 }
 246
 247 static inline void bio_cnt_set(struct bio *bio, unsigned int count)
 248 {
 249         if (count != 1) {
 250                 bio->bi_flags |= (1 << BIO_REFFED);
 251                 smp_mb__before_atomic();
 252         }
 253         atomic_set(&bio->__bi_cnt, count);
 254 }
 255
 256 static inline bool bio_flagged(struct bio *bio, unsigned int bit)
 257 {
 258         return (bio->bi_flags & (1U << bit)) != 0;
 259 }
 260
 261 static inline void bio_set_flag(struct bio *bio, unsigned int bit)
 262 {
 263         bio->bi_flags |= (1U << bit);
 264 }
 265
 266 static inline void bio_clear_flag(struct bio *bio, unsigned int bit)
 267 {
 268         bio->bi_flags &= ~(1U << bit);
 269 }
 270
 271 static inline void bio_get_first_bvec(struct bio *bio, struct bio_vec *bv)
 272 {
 273         *bv = bio_iovec(bio);
 274 }
 275
 276 static inline void bio_get_last_bvec(struct bio *bio, struct bio_vec *bv)
 277 {
 278         struct bvec_iter iter = bio->bi_iter;
 279         int idx;
 280
 281         if (unlikely(!bio_multiple_segments(bio))) {
 282                 *bv = bio_iovec(bio);
 283                 return;
 284         }
 285
 286         bio_advance_iter(bio, &iter, iter.bi_size);
 287
 288         if (!iter.bi_bvec_done)
 289                 idx = iter.bi_idx - 1;
 290         else    /* in the middle of bvec */
 291                 idx = iter.bi_idx;
 292
 293         *bv = bio->bi_io_vec[idx];
 294
 295         /*
 296          * iter.bi_bvec_done records actual length of the last bvec
 297          * if this bio ends in the middle of one io vector
 298          */
 299         if (iter.bi_bvec_done)
 300                 bv->bv_len = iter.bi_bvec_done;
 301 }
 302
 303 static inline unsigned bio_pages_all(struct bio *bio)
 304 {
 305         WARN_ON_ONCE(bio_flagged(bio, BIO_CLONED));
 306         return bio->bi_vcnt;
 307 }
 308
 309 static inline struct bio_vec *bio_first_bvec_all(struct bio *bio)
 310 {
 311         WARN_ON_ONCE(bio_flagged(bio, BIO_CLONED));
 312         return bio->bi_io_vec;
 313 }
 314
 315 static inline struct page *bio_first_page_all(struct bio *bio)
 316 {
 317         return bio_first_bvec_all(bio)->bv_page;
 318 }
 319
 320 static inline struct bio_vec *bio_last_bvec_all(struct bio *bio)
 321 {
 322         WARN_ON_ONCE(bio_flagged(bio, BIO_CLONED));
 323         return &bio->bi_io_vec[bio->bi_vcnt - 1];
 324 }
 325
 326 enum bip_flags {
 327         BIP_BLOCK_INTEGRITY     = 1 << 0, /* block layer owns integrity data */
 328         BIP_MAPPED_INTEGRITY    = 1 << 1, /* ref tag has been remapped */
 329         BIP_CTRL_NOCHECK        = 1 << 2, /* disable HBA integrity checking */
 330         BIP_DISK_NOCHECK        = 1 << 3, /* disable disk integrity checking */
 331         BIP_IP_CHECKSUM         = 1 << 4, /* IP checksum */
 332 };
 333
 334 /*
 335  * bio integrity payload
 336  */
 337 struct bio_integrity_payload {
 338         struct bio              *bip_bio;       /* parent bio */
 339
 340         struct bvec_iter        bip_iter;
 341
 342         unsigned short          bip_slab;       /* slab the bip came from */
 343         unsigned short          bip_vcnt;       /* # of integrity bio_vecs */
 344         unsigned short          bip_max_vcnt;   /* integrity bio_vec slots */
 345         unsigned short          bip_flags;      /* control flags */
 346
 347         struct work_struct      bip_work;       /* I/O completion */
 348
 349         struct bio_vec          *bip_vec;
 350         struct bio_vec          bip_inline_vecs[0];/* embedded bvec array */
 351 };
 352
 353 #if defined(CONFIG_BLK_DEV_INTEGRITY)
 354
 355 static inline struct bio_integrity_payload *bio_integrity(struct bio *bio)
 356 {
 357         if (bio->bi_opf & REQ_INTEGRITY)
 358                 return bio->bi_integrity;
 359
 360         return NULL;
 361 }
 362
 363 static inline bool bio_integrity_flagged(struct bio *bio, enum bip_flags flag)
 364 {
 365         struct bio_integrity_payload *bip = bio_integrity(bio);
 366
 367         if (bip)
 368                 return bip->bip_flags & flag;
 369
 370         return false;
 371 }
 372
 373 static inline sector_t bip_get_seed(struct bio_integrity_payload *bip)
 374 {
 375         return bip->bip_iter.bi_sector;
 376 }
 377
 378 static inline void bip_set_seed(struct bio_integrity_payload *bip,
 379                                 sector_t seed)
 380 {
 381         bip->bip_iter.bi_sector = seed;
 382 }
 383
 384 #endif /* CONFIG_BLK_DEV_INTEGRITY */
 385
 386 extern void bio_trim(struct bio *bio, int offset, int size);
 387 extern struct bio *bio_split(struct bio *bio, int sectors,
 388                              gfp_t gfp, struct bio_set *bs);
 389
 390 /**
 391  * bio_next_split - get next @sectors from a bio, splitting if necessary
 392  * @bio:        bio to split
 393  * @sectors:    number of sectors to split from the front of @bio
 394  * @gfp:        gfp mask
 395  * @bs:         bio set to allocate from
 396  *
 397  * Returns a bio representing the next @sectors of @bio - if the bio is smaller
 398  * than @sectors, returns the original bio unchanged.
 399  */
 400 static inline struct bio *bio_next_split(struct bio *bio, int sectors,
 401                                          gfp_t gfp, struct bio_set *bs)
 402 {
 403         if (sectors >= bio_sectors(bio))
 404                 return bio;
 405
 406         return bio_split(bio, sectors, gfp, bs);
 407 }
 408
 409 extern struct bio_set *bioset_create(unsigned int, unsigned int, int flags);
 410 enum {
 411         BIOSET_NEED_BVECS = BIT(0),
 412         BIOSET_NEED_RESCUER = BIT(1),
 413 };
 414 extern void bioset_free(struct bio_set *);
 415 extern mempool_t *biovec_create_pool(int pool_entries);
 416
 417 extern struct bio *bio_alloc_bioset(gfp_t, unsigned int, struct bio_set *);
 418 extern void bio_put(struct bio *);
 419
 420 extern void __bio_clone_fast(struct bio *, struct bio *);
 421 extern struct bio *bio_clone_fast(struct bio *, gfp_t, struct bio_set *);
 422 extern struct bio *bio_clone_bioset(struct bio *, gfp_t, struct bio_set *bs);
 423
 424 extern struct bio_set *fs_bio_set;
 425
 426 static inline struct bio *bio_alloc(gfp_t gfp_mask, unsigned int nr_iovecs)
 427 {
 428         return bio_alloc_bioset(gfp_mask, nr_iovecs, fs_bio_set);
 429 }
 430
 431 static inline struct bio *bio_kmalloc(gfp_t gfp_mask, unsigned int nr_iovecs)
 432 {
 433         return bio_alloc_bioset(gfp_mask, nr_iovecs, NULL);
 434 }
 435
 436 static inline struct bio *bio_clone_kmalloc(struct bio *bio, gfp_t gfp_mask)
 437 {
 438         return bio_clone_bioset(bio, gfp_mask, NULL);
 439
 440 }
 441
 442 extern blk_qc_t submit_bio(struct bio *);
 443
 444 extern void bio_endio(struct bio *);
 445
 446 static inline void bio_io_error(struct bio *bio)
 447 {
 448         bio->bi_status = BLK_STS_IOERR;
 449         bio_endio(bio);
 450 }
 451
 452 static inline void bio_wouldblock_error(struct bio *bio)
 453 {
 454         bio->bi_status = BLK_STS_AGAIN;
 455         bio_endio(bio);
 456 }
 457
 458 struct request_queue;
 459 extern int bio_phys_segments(struct request_queue *, struct bio *);
 460
 461 extern int submit_bio_wait(struct bio *bio);
 462 extern void bio_advance(struct bio *, unsigned);
 463
 464 extern void bio_init(struct bio *bio, struct bio_vec *table,
 465                      unsigned short max_vecs);
 466 extern void bio_uninit(struct bio *);
 467 extern void bio_reset(struct bio *);
 468 void bio_chain(struct bio *, struct bio *);
 469
 470 extern int bio_add_page(struct bio *, struct page *, unsigned int,unsigned int);
 471 extern int bio_add_pc_page(struct request_queue *, struct bio *, struct page *,
 472                            unsigned int, unsigned int);
 473 int bio_iov_iter_get_pages(struct bio *bio, struct iov_iter *iter);
 474 struct rq_map_data;
 475 extern struct bio *bio_map_user_iov(struct request_queue *,
 476                                     struct iov_iter *, gfp_t);
 477 extern void bio_unmap_user(struct bio *);
 478 extern struct bio *bio_map_kern(struct request_queue *, void *, unsigned int,
 479                                 gfp_t);
 480 extern struct bio *bio_copy_kern(struct request_queue *, void *, unsigned int,
 481                                  gfp_t, int);
 482 extern void bio_set_pages_dirty(struct bio *bio);
 483 extern void bio_check_pages_dirty(struct bio *bio);
 484
 485 void generic_start_io_acct(struct request_queue *q, int rw,
 486                                 unsigned long sectors, struct hd_struct *part);
 487 void generic_end_io_acct(struct request_queue *q, int rw,
 488                                 struct hd_struct *part,
 489                                 unsigned long start_time);
 490
 491 #ifndef ARCH_IMPLEMENTS_FLUSH_DCACHE_PAGE
 492 # error "You should define ARCH_IMPLEMENTS_FLUSH_DCACHE_PAGE for your platform"
 493 #endif
 494 #if ARCH_IMPLEMENTS_FLUSH_DCACHE_PAGE
 495 extern void bio_flush_dcache_pages(struct bio *bi);
 496 #else
 497 static inline void bio_flush_dcache_pages(struct bio *bi)
 498 {
 499 }
 500 #endif
 501
 502 extern void bio_copy_data(struct bio *dst, struct bio *src);
 503 extern void bio_free_pages(struct bio *bio);
 504
 505 extern struct bio *bio_copy_user_iov(struct request_queue *,
 506                                      struct rq_map_data *,
 507                                      struct iov_iter *,
 508                                      gfp_t);
 509 extern int bio_uncopy_user(struct bio *);
 510 void zero_fill_bio(struct bio *bio);
 511 extern struct bio_vec *bvec_alloc(gfp_t, int, unsigned long *, mempool_t *);
 512 extern void bvec_free(mempool_t *, struct bio_vec *, unsigned int);
 513 extern unsigned int bvec_nr_vecs(unsigned short idx);
 514 extern const char *bio_devname(struct bio *bio, char *buffer);
 515
 516 #define bio_set_dev(bio, bdev)                  \
 517 do {                                            \
 518         if ((bio)->bi_disk != (bdev)->bd_disk)  \
 519                 bio_clear_flag(bio, BIO_THROTTLED);\
 520         (bio)->bi_disk = (bdev)->bd_disk;       \
 521         (bio)->bi_partno = (bdev)->bd_partno;   \
 522 } while (0)
 523
 524 #define bio_copy_dev(dst, src)                  \
 525 do {                                            \
 526         (dst)->bi_disk = (src)->bi_disk;        \
 527         (dst)->bi_partno = (src)->bi_partno;    \
 528 } while (0)
 529
 530 #define bio_dev(bio) \
 531         disk_devt((bio)->bi_disk)
 532
 533 #ifdef CONFIG_BLK_CGROUP
 534 int bio_associate_blkcg(struct bio *bio, struct cgroup_subsys_state *blkcg_css);
 535 void bio_disassociate_task(struct bio *bio);
 536 void bio_clone_blkcg_association(struct bio *dst, struct bio *src);
 537 #else   /* CONFIG_BLK_CGROUP */
 538 static inline int bio_associate_blkcg(struct bio *bio,
 539                         struct cgroup_subsys_state *blkcg_css) { return 0; }
 540 static inline void bio_disassociate_task(struct bio *bio) { }
 541 static inline void bio_clone_blkcg_association(struct bio *dst,
 542                         struct bio *src) { }
 543 #endif  /* CONFIG_BLK_CGROUP */
 544
 545 #ifdef CONFIG_HIGHMEM
 546 /*
 547  * remember never ever reenable interrupts between a bvec_kmap_irq and
 548  * bvec_kunmap_irq!
 549  */
 550 static inline char *bvec_kmap_irq(struct bio_vec *bvec, unsigned long *flags)
 551 {
 552         unsigned long addr;
 553
 554         /*
 555          * might not be a highmem page, but the preempt/irq count
 556          * balancing is a lot nicer this way
 557          */
 558         local_irq_save(*flags);
 559         addr = (unsigned long) kmap_atomic(bvec->bv_page);
 560
 561         BUG_ON(addr & ~PAGE_MASK);
 562
 563         return (char *) addr + bvec->bv_offset;
 564 }
 565
 566 static inline void bvec_kunmap_irq(char *buffer, unsigned long *flags)
 567 {
 568         unsigned long ptr = (unsigned long) buffer & PAGE_MASK;
 569
 570         kunmap_atomic((void *) ptr);
 571         local_irq_restore(*flags);
 572 }
 573
 574 #else
 575 static inline char *bvec_kmap_irq(struct bio_vec *bvec, unsigned long *flags)
 576 {
 577         return page_address(bvec->bv_page) + bvec->bv_offset;
 578 }
 579
 580 static inline void bvec_kunmap_irq(char *buffer, unsigned long *flags)
 581 {
 582         *flags = 0;
 583 }
 584 #endif
 585
 586 /*
 587  * BIO list management for use by remapping drivers (e.g. DM or MD) and loop.
 588  *
 589  * A bio_list anchors a singly-linked list of bios chained through the bi_next
 590  * member of the bio.  The bio_list also caches the last list member to allow
 591  * fast access to the tail.
 592  */
 593 struct bio_list {
 594         struct bio *head;
 595         struct bio *tail;
 596 };
 597
 598 static inline int bio_list_empty(const struct bio_list *bl)
 599 {
 600         return bl->head == NULL;
 601 }
 602
 603 static inline void bio_list_init(struct bio_list *bl)
 604 {
 605         bl->head = bl->tail = NULL;
 606 }
 607
 608 #define BIO_EMPTY_LIST  { NULL, NULL }
 609
 610 #define bio_list_for_each(bio, bl) \
 611         for (bio = (bl)->head; bio; bio = bio->bi_next)
 612
 613 static inline unsigned bio_list_size(const struct bio_list *bl)
 614 {
 615         unsigned sz = 0;
 616         struct bio *bio;
 617
 618         bio_list_for_each(bio, bl)
 619                 sz++;
 620
 621         return sz;
 622 }
 623
 624 static inline void bio_list_add(struct bio_list *bl, struct bio *bio)
 625 {
 626         bio->bi_next = NULL;
 627
 628         if (bl->tail)
 629                 bl->tail->bi_next = bio;
 630         else
 631                 bl->head = bio;
 632
 633         bl->tail = bio;
 634 }
 635
 636 static inline void bio_list_add_head(struct bio_list *bl, struct bio *bio)
 637 {
 638         bio->bi_next = bl->head;
 639
 640         bl->head = bio;
 641
 642         if (!bl->tail)
 643                 bl->tail = bio;
 644 }
 645
 646 static inline void bio_list_merge(struct bio_list *bl, struct bio_list *bl2)
 647 {
 648         if (!bl2->head)
 649                 return;
 650
 651         if (bl->tail)
 652                 bl->tail->bi_next = bl2->head;
 653         else
 654                 bl->head = bl2->head;
 655
 656         bl->tail = bl2->tail;
 657 }
 658
 659 static inline void bio_list_merge_head(struct bio_list *bl,
 660                                        struct bio_list *bl2)
 661 {
 662         if (!bl2->head)
 663                 return;
 664
 665         if (bl->head)
 666                 bl2->tail->bi_next = bl->head;
 667         else
 668                 bl->tail = bl2->tail;
 669
 670         bl->head = bl2->head;
 671 }
 672
 673 static inline struct bio *bio_list_peek(struct bio_list *bl)
 674 {
 675         return bl->head;
 676 }
 677
 678 static inline struct bio *bio_list_pop(struct bio_list *bl)
 679 {
 680         struct bio *bio = bl->head;
 681
 682         if (bio) {
 683                 bl->head = bl->head->bi_next;
 684                 if (!bl->head)
 685                         bl->tail = NULL;
 686
 687                 bio->bi_next = NULL;
 688         }
 689
 690         return bio;
 691 }
 692
 693 static inline struct bio *bio_list_get(struct bio_list *bl)
 694 {
 695         struct bio *bio = bl->head;
 696
 697         bl->head = bl->tail = NULL;
 698
 699         return bio;
 700 }
 701
 702 /*
 703  * Increment chain count for the bio. Make sure the CHAIN flag update
 704  * is visible before the raised count.
 705  */
 706 static inline void bio_inc_remaining(struct bio *bio)
 707 {
 708         bio_set_flag(bio, BIO_CHAIN);
 709         smp_mb__before_atomic();
 710         atomic_inc(&bio->__bi_remaining);
 711 }
 712
 713 /*
 714  * bio_set is used to allow other portions of the IO system to
 715  * allocate their own private memory pools for bio and iovec structures.
 716  * These memory pools in turn all allocate from the bio_slab
 717  * and the bvec_slabs[].
 718  */
 719 #define BIO_POOL_SIZE 2
 720
 721 struct bio_set {
 722         struct kmem_cache *bio_slab;
 723         unsigned int front_pad;
 724
 725         mempool_t *bio_pool;
 726         mempool_t *bvec_pool;
 727 #if defined(CONFIG_BLK_DEV_INTEGRITY)
 728         mempool_t *bio_integrity_pool;
 729         mempool_t *bvec_integrity_pool;
 730 #endif
 731
 732         /*
 733          * Deadlock avoidance for stacking block drivers: see comments in
 734          * bio_alloc_bioset() for details
 735          */
 736         spinlock_t              rescue_lock;
 737         struct bio_list         rescue_list;
 738         struct work_struct      rescue_work;
 739         struct workqueue_struct *rescue_workqueue;
 740 };
 741
 742 struct biovec_slab {
 743         int nr_vecs;
 744         char *name;
 745         struct kmem_cache *slab;
 746 };
 747
 748 /*
 749  * a small number of entries is fine, not going to be performance critical.
 750  * basically we just need to survive
 751  */
 752 #define BIO_SPLIT_ENTRIES 2
 753
 754 #if defined(CONFIG_BLK_DEV_INTEGRITY)
 755
 756 #define bip_for_each_vec(bvl, bip, iter)                                \
 757         for_each_bvec(bvl, (bip)->bip_vec, iter, (bip)->bip_iter)
 758
 759 #define bio_for_each_integrity_vec(_bvl, _bio, _iter)                   \
 760         for_each_bio(_bio)                                              \
 761                 bip_for_each_vec(_bvl, _bio->bi_integrity, _iter)
 762
 763 extern struct bio_integrity_payload *bio_integrity_alloc(struct bio *, gfp_t, unsigned int);
 764 extern int bio_integrity_add_page(struct bio *, struct page *, unsigned int, unsigned int);
 765 extern bool bio_integrity_prep(struct bio *);
 766 extern void bio_integrity_advance(struct bio *, unsigned int);
 767 extern void bio_integrity_trim(struct bio *);
 768 extern int bio_integrity_clone(struct bio *, struct bio *, gfp_t);
 769 extern int bioset_integrity_create(struct bio_set *, int);
 770 extern void bioset_integrity_free(struct bio_set *);
 771 extern void bio_integrity_init(void);
 772
 773 #else /* CONFIG_BLK_DEV_INTEGRITY */
 774
 775 static inline void *bio_integrity(struct bio *bio)
 776 {
 777         return NULL;
 778 }
 779
 780 static inline int bioset_integrity_create(struct bio_set *bs, int pool_size)
 781 {
 782         return 0;
 783 }
 784
 785 static inline void bioset_integrity_free (struct bio_set *bs)
 786 {
 787         return;
 788 }
 789
 790 static inline bool bio_integrity_prep(struct bio *bio)
 791 {
 792         return true;
 793 }
 794
 795 static inline int bio_integrity_clone(struct bio *bio, struct bio *bio_src,
 796                                       gfp_t gfp_mask)
 797 {
 798         return 0;
 799 }
 800
 801 static inline void bio_integrity_advance(struct bio *bio,
 802                                          unsigned int bytes_done)
 803 {
 804         return;
 805 }
 806
 807 static inline void bio_integrity_trim(struct bio *bio)
 808 {
 809         return;
 810 }
 811
 812 static inline void bio_integrity_init(void)
 813 {
 814         return;
 815 }
 816
 817 static inline bool bio_integrity_flagged(struct bio *bio, enum bip_flags flag)
 818 {
 819         return false;
 820 }
 821
 822 static inline void *bio_integrity_alloc(struct bio * bio, gfp_t gfp,
 823                                                                 unsigned int nr)
 824 {
 825         return ERR_PTR(-EINVAL);
 826 }
 827
 828 static inline int bio_integrity_add_page(struct bio *bio, struct page *page,
 829                                         unsigned int len, unsigned int offset)
 830 {
 831         return 0;
 832 }
 833
 834 #endif /* CONFIG_BLK_DEV_INTEGRITY */
 835
 836 #endif /* CONFIG_BLOCK */
 837 #endif /* __LINUX_BIO_H */