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