include/linux/bio.h

   1 /*
   2  * 2.5 block I/O model
   3  *
   4  * Copyright (C) 2001 Jens Axboe <axboe@suse.de>
   5  *
   6  * This program is free software; you can redistribute it and/or modify
   7  * it under the terms of the GNU General Public License version 2 as
   8  * published by the Free Software Foundation.
   9  *
  10  * This program is distributed in the hope that it will be useful,
  11  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  12  *
  13  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  14  * GNU General Public License for more details.
  15  *
  16  * You should have received a copy of the GNU General Public Licens
  17  * along with this program; if not, write to the Free Software
  18  * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-
  19  */
  20 #ifndef __LINUX_BIO_H
  21 #define __LINUX_BIO_H
  22
  23 #include <linux/highmem.h>
  24 #include <linux/mempool.h>
  25 #include <linux/ioprio.h>
  26 #include <linux/bug.h>
  27
  28 #ifdef CONFIG_BLOCK
  29
  30 #include <asm/io.h>
  31
  32 /* struct bio, bio_vec and BIO_* flags are defined in blk_types.h */
  33 #include <linux/blk_types.h>
  34
  35 #define BIO_DEBUG
  36
  37 #ifdef BIO_DEBUG
  38 #define BIO_BUG_ON      BUG_ON
  39 #else
  40 #define BIO_BUG_ON
  41 #endif
  42
  43 #define BIO_MAX_PAGES           256
  44
  45 #define bio_prio(bio)                   (bio)->bi_ioprio
  46 #define bio_set_prio(bio, prio)         ((bio)->bi_ioprio = prio)
  47
  48 #define bio_iter_iovec(bio, iter)                               \
  49         bvec_iter_bvec((bio)->bi_io_vec, (iter))
  50
  51 #define bio_iter_page(bio, iter)                                \
  52         bvec_iter_page((bio)->bi_io_vec, (iter))
  53 #define bio_iter_len(bio, iter)                                 \
  54         bvec_iter_len((bio)->bi_io_vec, (iter))
  55 #define bio_iter_offset(bio, iter)                              \
  56         bvec_iter_offset((bio)->bi_io_vec, (iter))
  57
  58 #define bio_page(bio)           bio_iter_page((bio), (bio)->bi_iter)
  59 #define bio_offset(bio)         bio_iter_offset((bio), (bio)->bi_iter)
  60 #define bio_iovec(bio)          bio_iter_iovec((bio), (bio)->bi_iter)
  61
  62 #define bio_multiple_segments(bio)                              \
  63         ((bio)->bi_iter.bi_size != bio_iovec(bio).bv_len)
  64 #define bio_sectors(bio)        ((bio)->bi_iter.bi_size >> 9)
  65 #define bio_end_sector(bio)     ((bio)->bi_iter.bi_sector + bio_sectors((bio)))
  66
  67 /*
  68  * Check whether this bio carries any data or not. A NULL bio is allowed.
  69  */
  70 static inline bool bio_has_data(struct bio *bio)
  71 {
  72         if (bio &&
  73             bio->bi_iter.bi_size &&
  74             bio_op(bio) != REQ_OP_DISCARD)
  75                 return true;
  76
  77         return false;
  78 }
  79
  80 static inline bool bio_no_advance_iter(struct bio *bio)
  81 {
  82         return bio_op(bio) == REQ_OP_DISCARD || bio_op(bio) == REQ_OP_WRITE_SAME;
  83 }
  84
  85 static inline bool bio_is_rw(struct bio *bio)
  86 {
  87         if (!bio_has_data(bio))
  88                 return false;
  89
  90         if (bio_no_advance_iter(bio))
  91                 return false;
  92
  93         return true;
  94 }
  95
  96 static inline bool bio_mergeable(struct bio *bio)
  97 {
  98         if (bio->bi_opf & REQ_NOMERGE_FLAGS)
  99                 return false;
 100
 101         return true;
 102 }
 103
 104 static inline unsigned int bio_cur_bytes(struct bio *bio)
 105 {
 106         if (bio_has_data(bio))
 107                 return bio_iovec(bio).bv_len;
 108         else /* dataless requests such as discard */
 109                 return bio->bi_iter.bi_size;
 110 }
 111
 112 static inline void *bio_data(struct bio *bio)
 113 {
 114         if (bio_has_data(bio))
 115                 return page_address(bio_page(bio)) + bio_offset(bio);
 116
 117         return NULL;
 118 }
 119
 120 /*
 121  * will die
 122  */
 123 #define bio_to_phys(bio)        (page_to_phys(bio_page((bio))) + (unsigned long) bio_offset((bio)))
 124 #define bvec_to_phys(bv)        (page_to_phys((bv)->bv_page) + (unsigned long) (bv)->bv_offset)
 125
 126 /*
 127  * queues that have highmem support enabled may still need to revert to
 128  * PIO transfers occasionally and thus map high pages temporarily. For
 129  * permanent PIO fall back, user is probably better off disabling highmem
 130  * I/O completely on that queue (see ide-dma for example)
 131  */
 132 #define __bio_kmap_atomic(bio, iter)                            \
 133         (kmap_atomic(bio_iter_iovec((bio), (iter)).bv_page) +   \
 134                 bio_iter_iovec((bio), (iter)).bv_offset)
 135
 136 #define __bio_kunmap_atomic(addr)       kunmap_atomic(addr)
 137
 138 /*
 139  * merge helpers etc
 140  */
 141
 142 /* Default implementation of BIOVEC_PHYS_MERGEABLE */
 143 #define __BIOVEC_PHYS_MERGEABLE(vec1, vec2)     \
 144         ((bvec_to_phys((vec1)) + (vec1)->bv_len) == bvec_to_phys((vec2)))
 145
 146 /*
 147  * allow arch override, for eg virtualized architectures (put in asm/io.h)
 148  */
 149 #ifndef BIOVEC_PHYS_MERGEABLE
 150 #define BIOVEC_PHYS_MERGEABLE(vec1, vec2)       \
 151         __BIOVEC_PHYS_MERGEABLE(vec1, vec2)
 152 #endif
 153
 154 #define __BIO_SEG_BOUNDARY(addr1, addr2, mask) \
 155         (((addr1) | (mask)) == (((addr2) - 1) | (mask)))
 156 #define BIOVEC_SEG_BOUNDARY(q, b1, b2) \
 157         __BIO_SEG_BOUNDARY(bvec_to_phys((b1)), bvec_to_phys((b2)) + (b2)->bv_len, queue_segment_boundary((q)))
 158
 159 /*
 160  * drivers should _never_ use the all version - the bio may have been split
 161  * before it got to the driver and the driver won't own all of it
 162  */
 163 #define bio_for_each_segment_all(bvl, bio, i)                           \
 164         for (i = 0, bvl = (bio)->bi_io_vec; i < (bio)->bi_vcnt; i++, bvl++)
 165
 166 static inline void bio_advance_iter(struct bio *bio, struct bvec_iter *iter,
 167                                     unsigned bytes)
 168 {
 169         iter->bi_sector += bytes >> 9;
 170
 171         if (bio_no_advance_iter(bio))
 172                 iter->bi_size -= bytes;
 173         else
 174                 bvec_iter_advance(bio->bi_io_vec, iter, bytes);
 175 }
 176
 177 #define __bio_for_each_segment(bvl, bio, iter, start)                   \
 178         for (iter = (start);                                            \
 179              (iter).bi_size &&                                          \
 180                 ((bvl = bio_iter_iovec((bio), (iter))), 1);             \
 181              bio_advance_iter((bio), &(iter), (bvl).bv_len))
 182
 183 #define bio_for_each_segment(bvl, bio, iter)                            \
 184         __bio_for_each_segment(bvl, bio, iter, (bio)->bi_iter)
 185
 186 #define bio_iter_last(bvec, iter) ((iter).bi_size == (bvec).bv_len)
 187
 188 static inline unsigned bio_segments(struct bio *bio)
 189 {
 190         unsigned segs = 0;
 191         struct bio_vec bv;
 192         struct bvec_iter iter;
 193
 194         /*
 195          * We special case discard/write same, because they interpret bi_size
 196          * differently:
 197          */
 198
 199         if (bio_op(bio) == REQ_OP_DISCARD)
 200                 return 1;
 201
 202         if (bio_op(bio) == REQ_OP_WRITE_SAME)
 203                 return 1;
 204
 205         bio_for_each_segment(bv, bio, iter)
 206                 segs++;
 207
 208         return segs;
 209 }
 210
 211 /*
 212  * get a reference to a bio, so it won't disappear. the intended use is
 213  * something like:
 214  *
 215  * bio_get(bio);
 216  * submit_bio(rw, bio);
 217  * if (bio->bi_flags ...)
 218  *      do_something
 219  * bio_put(bio);
 220  *
 221  * without the bio_get(), it could potentially complete I/O before submit_bio
 222  * returns. and then bio would be freed memory when if (bio->bi_flags ...)
 223  * runs
 224  */
 225 static inline void bio_get(struct bio *bio)
 226 {
 227         bio->bi_flags |= (1 << BIO_REFFED);
 228         smp_mb__before_atomic();
 229         atomic_inc(&bio->__bi_cnt);
 230 }
 231
 232 static inline void bio_cnt_set(struct bio *bio, unsigned int count)
 233 {
 234         if (count != 1) {
 235                 bio->bi_flags |= (1 << BIO_REFFED);
 236                 smp_mb__before_atomic();
 237         }
 238         atomic_set(&bio->__bi_cnt, count);
 239 }
 240
 241 static inline bool bio_flagged(struct bio *bio, unsigned int bit)
 242 {
 243         return (bio->bi_flags & (1U << bit)) != 0;
 244 }
 245
 246 static inline void bio_set_flag(struct bio *bio, unsigned int bit)
 247 {
 248         bio->bi_flags |= (1U << bit);
 249 }
 250
 251 static inline void bio_clear_flag(struct bio *bio, unsigned int bit)
 252 {
 253         bio->bi_flags &= ~(1U << bit);
 254 }
 255
 256 static inline void bio_get_first_bvec(struct bio *bio, struct bio_vec *bv)
 257 {
 258         *bv = bio_iovec(bio);
 259 }
 260
 261 static inline void bio_get_last_bvec(struct bio *bio, struct bio_vec *bv)
 262 {
 263         struct bvec_iter iter = bio->bi_iter;
 264         int idx;
 265
 266         if (unlikely(!bio_multiple_segments(bio))) {
 267                 *bv = bio_iovec(bio);
 268                 return;
 269         }
 270
 271         bio_advance_iter(bio, &iter, iter.bi_size);
 272
 273         if (!iter.bi_bvec_done)
 274                 idx = iter.bi_idx - 1;
 275         else    /* in the middle of bvec */
 276                 idx = iter.bi_idx;
 277
 278         *bv = bio->bi_io_vec[idx];
 279
 280         /*
 281          * iter.bi_bvec_done records actual length of the last bvec
 282          * if this bio ends in the middle of one io vector
 283          */
 284         if (iter.bi_bvec_done)
 285                 bv->bv_len = iter.bi_bvec_done;
 286 }
 287
 288 enum bip_flags {
 289         BIP_BLOCK_INTEGRITY     = 1 << 0, /* block layer owns integrity data */
 290         BIP_MAPPED_INTEGRITY    = 1 << 1, /* ref tag has been remapped */
 291         BIP_CTRL_NOCHECK        = 1 << 2, /* disable HBA integrity checking */
 292         BIP_DISK_NOCHECK        = 1 << 3, /* disable disk integrity checking */
 293         BIP_IP_CHECKSUM         = 1 << 4, /* IP checksum */
 294 };
 295
 296 /*
 297  * bio integrity payload
 298  */
 299 struct bio_integrity_payload {
 300         struct bio              *bip_bio;       /* parent bio */
 301
 302         struct bvec_iter        bip_iter;
 303
 304         bio_end_io_t            *bip_end_io;    /* saved I/O completion fn */
 305
 306         unsigned short          bip_slab;       /* slab the bip came from */
 307         unsigned short          bip_vcnt;       /* # of integrity bio_vecs */
 308         unsigned short          bip_max_vcnt;   /* integrity bio_vec slots */
 309         unsigned short          bip_flags;      /* control flags */
 310
 311         struct work_struct      bip_work;       /* I/O completion */
 312
 313         struct bio_vec          *bip_vec;
 314         struct bio_vec          bip_inline_vecs[0];/* embedded bvec array */
 315 };
 316
 317 #if defined(CONFIG_BLK_DEV_INTEGRITY)
 318
 319 static inline struct bio_integrity_payload *bio_integrity(struct bio *bio)
 320 {
 321         if (bio->bi_opf & REQ_INTEGRITY)
 322                 return bio->bi_integrity;
 323
 324         return NULL;
 325 }
 326
 327 static inline bool bio_integrity_flagged(struct bio *bio, enum bip_flags flag)
 328 {
 329         struct bio_integrity_payload *bip = bio_integrity(bio);
 330
 331         if (bip)
 332                 return bip->bip_flags & flag;
 333
 334         return false;
 335 }
 336
 337 static inline sector_t bip_get_seed(struct bio_integrity_payload *bip)
 338 {
 339         return bip->bip_iter.bi_sector;
 340 }
 341
 342 static inline void bip_set_seed(struct bio_integrity_payload *bip,
 343                                 sector_t seed)
 344 {
 345         bip->bip_iter.bi_sector = seed;
 346 }
 347
 348 #endif /* CONFIG_BLK_DEV_INTEGRITY */
 349
 350 extern void bio_trim(struct bio *bio, int offset, int size);
 351 extern struct bio *bio_split(struct bio *bio, int sectors,
 352                              gfp_t gfp, struct bio_set *bs);
 353
 354 /**
 355  * bio_next_split - get next @sectors from a bio, splitting if necessary
 356  * @bio:        bio to split
 357  * @sectors:    number of sectors to split from the front of @bio
 358  * @gfp:        gfp mask
 359  * @bs:         bio set to allocate from
 360  *
 361  * Returns a bio representing the next @sectors of @bio - if the bio is smaller
 362  * than @sectors, returns the original bio unchanged.
 363  */
 364 static inline struct bio *bio_next_split(struct bio *bio, int sectors,
 365                                          gfp_t gfp, struct bio_set *bs)
 366 {
 367         if (sectors >= bio_sectors(bio))
 368                 return bio;
 369
 370         return bio_split(bio, sectors, gfp, bs);
 371 }
 372
 373 extern struct bio_set *bioset_create(unsigned int, unsigned int);
 374 extern struct bio_set *bioset_create_nobvec(unsigned int, unsigned int);
 375 extern void bioset_free(struct bio_set *);
 376 extern mempool_t *biovec_create_pool(int pool_entries);
 377
 378 extern struct bio *bio_alloc_bioset(gfp_t, int, struct bio_set *);
 379 extern void bio_put(struct bio *);
 380
 381 extern void __bio_clone_fast(struct bio *, struct bio *);
 382 extern struct bio *bio_clone_fast(struct bio *, gfp_t, struct bio_set *);
 383 extern struct bio *bio_clone_bioset(struct bio *, gfp_t, struct bio_set *bs);
 384
 385 extern struct bio_set *fs_bio_set;
 386
 387 static inline struct bio *bio_alloc(gfp_t gfp_mask, unsigned int nr_iovecs)
 388 {
 389         return bio_alloc_bioset(gfp_mask, nr_iovecs, fs_bio_set);
 390 }
 391
 392 static inline struct bio *bio_clone(struct bio *bio, gfp_t gfp_mask)
 393 {
 394         return bio_clone_bioset(bio, gfp_mask, fs_bio_set);
 395 }
 396
 397 static inline struct bio *bio_kmalloc(gfp_t gfp_mask, unsigned int nr_iovecs)
 398 {
 399         return bio_alloc_bioset(gfp_mask, nr_iovecs, NULL);
 400 }
 401
 402 static inline struct bio *bio_clone_kmalloc(struct bio *bio, gfp_t gfp_mask)
 403 {
 404         return bio_clone_bioset(bio, gfp_mask, NULL);
 405
 406 }
 407
 408 extern void bio_endio(struct bio *);
 409
 410 static inline void bio_io_error(struct bio *bio)
 411 {
 412         bio->bi_error = -EIO;
 413         bio_endio(bio);
 414 }
 415
 416 struct request_queue;
 417 extern int bio_phys_segments(struct request_queue *, struct bio *);
 418
 419 extern int submit_bio_wait(struct bio *bio);
 420 extern void bio_advance(struct bio *, unsigned);
 421
 422 extern void bio_init(struct bio *);
 423 extern void bio_reset(struct bio *);
 424 void bio_chain(struct bio *, struct bio *);
 425
 426 extern int bio_add_page(struct bio *, struct page *, unsigned int,unsigned int);
 427 extern int bio_add_pc_page(struct request_queue *, struct bio *, struct page *,
 428                            unsigned int, unsigned int);
 429 struct rq_map_data;
 430 extern struct bio *bio_map_user_iov(struct request_queue *,
 431                                     const struct iov_iter *, gfp_t);
 432 extern void bio_unmap_user(struct bio *);
 433 extern struct bio *bio_map_kern(struct request_queue *, void *, unsigned int,
 434                                 gfp_t);
 435 extern struct bio *bio_copy_kern(struct request_queue *, void *, unsigned int,
 436                                  gfp_t, int);
 437 extern void bio_set_pages_dirty(struct bio *bio);
 438 extern void bio_check_pages_dirty(struct bio *bio);
 439
 440 void generic_start_io_acct(int rw, unsigned long sectors,
 441                            struct hd_struct *part);
 442 void generic_end_io_acct(int rw, struct hd_struct *part,
 443                          unsigned long start_time);
 444
 445 #ifndef ARCH_IMPLEMENTS_FLUSH_DCACHE_PAGE
 446 # error "You should define ARCH_IMPLEMENTS_FLUSH_DCACHE_PAGE for your platform"
 447 #endif
 448 #if ARCH_IMPLEMENTS_FLUSH_DCACHE_PAGE
 449 extern void bio_flush_dcache_pages(struct bio *bi);
 450 #else
 451 static inline void bio_flush_dcache_pages(struct bio *bi)
 452 {
 453 }
 454 #endif
 455
 456 extern void bio_copy_data(struct bio *dst, struct bio *src);
 457 extern int bio_alloc_pages(struct bio *bio, gfp_t gfp);
 458
 459 extern struct bio *bio_copy_user_iov(struct request_queue *,
 460                                      struct rq_map_data *,
 461                                      const struct iov_iter *,
 462                                      gfp_t);
 463 extern int bio_uncopy_user(struct bio *);
 464 void zero_fill_bio(struct bio *bio);
 465 extern struct bio_vec *bvec_alloc(gfp_t, int, unsigned long *, mempool_t *);
 466 extern void bvec_free(mempool_t *, struct bio_vec *, unsigned int);
 467 extern unsigned int bvec_nr_vecs(unsigned short idx);
 468
 469 #ifdef CONFIG_BLK_CGROUP
 470 int bio_associate_blkcg(struct bio *bio, struct cgroup_subsys_state *blkcg_css);
 471 int bio_associate_current(struct bio *bio);
 472 void bio_disassociate_task(struct bio *bio);
 473 void bio_clone_blkcg_association(struct bio *dst, struct bio *src);
 474 #else   /* CONFIG_BLK_CGROUP */
 475 static inline int bio_associate_blkcg(struct bio *bio,
 476                         struct cgroup_subsys_state *blkcg_css) { return 0; }
 477 static inline int bio_associate_current(struct bio *bio) { return -ENOENT; }
 478 static inline void bio_disassociate_task(struct bio *bio) { }
 479 static inline void bio_clone_blkcg_association(struct bio *dst,
 480                         struct bio *src) { }
 481 #endif  /* CONFIG_BLK_CGROUP */
 482
 483 #ifdef CONFIG_HIGHMEM
 484 /*
 485  * remember never ever reenable interrupts between a bvec_kmap_irq and
 486  * bvec_kunmap_irq!
 487  */
 488 static inline char *bvec_kmap_irq(struct bio_vec *bvec, unsigned long *flags)
 489 {
 490         unsigned long addr;
 491
 492         /*
 493          * might not be a highmem page, but the preempt/irq count
 494          * balancing is a lot nicer this way
 495          */
 496         local_irq_save(*flags);
 497         addr = (unsigned long) kmap_atomic(bvec->bv_page);
 498
 499         BUG_ON(addr & ~PAGE_MASK);
 500
 501         return (char *) addr + bvec->bv_offset;
 502 }
 503
 504 static inline void bvec_kunmap_irq(char *buffer, unsigned long *flags)
 505 {
 506         unsigned long ptr = (unsigned long) buffer & PAGE_MASK;
 507
 508         kunmap_atomic((void *) ptr);
 509         local_irq_restore(*flags);
 510 }
 511
 512 #else
 513 static inline char *bvec_kmap_irq(struct bio_vec *bvec, unsigned long *flags)
 514 {
 515         return page_address(bvec->bv_page) + bvec->bv_offset;
 516 }
 517
 518 static inline void bvec_kunmap_irq(char *buffer, unsigned long *flags)
 519 {
 520         *flags = 0;
 521 }
 522 #endif
 523
 524 static inline char *__bio_kmap_irq(struct bio *bio, struct bvec_iter iter,
 525                                    unsigned long *flags)
 526 {
 527         return bvec_kmap_irq(&bio_iter_iovec(bio, iter), flags);
 528 }
 529 #define __bio_kunmap_irq(buf, flags)    bvec_kunmap_irq(buf, flags)
 530
 531 #define bio_kmap_irq(bio, flags) \
 532         __bio_kmap_irq((bio), (bio)->bi_iter, (flags))
 533 #define bio_kunmap_irq(buf,flags)       __bio_kunmap_irq(buf, flags)
 534
 535 /*
 536  * BIO list management for use by remapping drivers (e.g. DM or MD) and loop.
 537  *
 538  * A bio_list anchors a singly-linked list of bios chained through the bi_next
 539  * member of the bio.  The bio_list also caches the last list member to allow
 540  * fast access to the tail.
 541  */
 542 struct bio_list {
 543         struct bio *head;
 544         struct bio *tail;
 545 };
 546
 547 static inline int bio_list_empty(const struct bio_list *bl)
 548 {
 549         return bl->head == NULL;
 550 }
 551
 552 static inline void bio_list_init(struct bio_list *bl)
 553 {
 554         bl->head = bl->tail = NULL;
 555 }
 556
 557 #define BIO_EMPTY_LIST  { NULL, NULL }
 558
 559 #define bio_list_for_each(bio, bl) \
 560         for (bio = (bl)->head; bio; bio = bio->bi_next)
 561
 562 static inline unsigned bio_list_size(const struct bio_list *bl)
 563 {
 564         unsigned sz = 0;
 565         struct bio *bio;
 566
 567         bio_list_for_each(bio, bl)
 568                 sz++;
 569
 570         return sz;
 571 }
 572
 573 static inline void bio_list_add(struct bio_list *bl, struct bio *bio)
 574 {
 575         bio->bi_next = NULL;
 576
 577         if (bl->tail)
 578                 bl->tail->bi_next = bio;
 579         else
 580                 bl->head = bio;
 581
 582         bl->tail = bio;
 583 }
 584
 585 static inline void bio_list_add_head(struct bio_list *bl, struct bio *bio)
 586 {
 587         bio->bi_next = bl->head;
 588
 589         bl->head = bio;
 590
 591         if (!bl->tail)
 592                 bl->tail = bio;
 593 }
 594
 595 static inline void bio_list_merge(struct bio_list *bl, struct bio_list *bl2)
 596 {
 597         if (!bl2->head)
 598                 return;
 599
 600         if (bl->tail)
 601                 bl->tail->bi_next = bl2->head;
 602         else
 603                 bl->head = bl2->head;
 604
 605         bl->tail = bl2->tail;
 606 }
 607
 608 static inline void bio_list_merge_head(struct bio_list *bl,
 609                                        struct bio_list *bl2)
 610 {
 611         if (!bl2->head)
 612                 return;
 613
 614         if (bl->head)
 615                 bl2->tail->bi_next = bl->head;
 616         else
 617                 bl->tail = bl2->tail;
 618
 619         bl->head = bl2->head;
 620 }
 621
 622 static inline struct bio *bio_list_peek(struct bio_list *bl)
 623 {
 624         return bl->head;
 625 }
 626
 627 static inline struct bio *bio_list_pop(struct bio_list *bl)
 628 {
 629         struct bio *bio = bl->head;
 630
 631         if (bio) {
 632                 bl->head = bl->head->bi_next;
 633                 if (!bl->head)
 634                         bl->tail = NULL;
 635
 636                 bio->bi_next = NULL;
 637         }
 638
 639         return bio;
 640 }
 641
 642 static inline struct bio *bio_list_get(struct bio_list *bl)
 643 {
 644         struct bio *bio = bl->head;
 645
 646         bl->head = bl->tail = NULL;
 647
 648         return bio;
 649 }
 650
 651 /*
 652  * Increment chain count for the bio. Make sure the CHAIN flag update
 653  * is visible before the raised count.
 654  */
 655 static inline void bio_inc_remaining(struct bio *bio)
 656 {
 657         bio_set_flag(bio, BIO_CHAIN);
 658         smp_mb__before_atomic();
 659         atomic_inc(&bio->__bi_remaining);
 660 }
 661
 662 /*
 663  * bio_set is used to allow other portions of the IO system to
 664  * allocate their own private memory pools for bio and iovec structures.
 665  * These memory pools in turn all allocate from the bio_slab
 666  * and the bvec_slabs[].
 667  */
 668 #define BIO_POOL_SIZE 2
 669
 670 struct bio_set {
 671         struct kmem_cache *bio_slab;
 672         unsigned int front_pad;
 673
 674         mempool_t *bio_pool;
 675         mempool_t *bvec_pool;
 676 #if defined(CONFIG_BLK_DEV_INTEGRITY)
 677         mempool_t *bio_integrity_pool;
 678         mempool_t *bvec_integrity_pool;
 679 #endif
 680
 681         /*
 682          * Deadlock avoidance for stacking block drivers: see comments in
 683          * bio_alloc_bioset() for details
 684          */
 685         spinlock_t              rescue_lock;
 686         struct bio_list         rescue_list;
 687         struct work_struct      rescue_work;
 688         struct workqueue_struct *rescue_workqueue;
 689 };
 690
 691 struct biovec_slab {
 692         int nr_vecs;
 693         char *name;
 694         struct kmem_cache *slab;
 695 };
 696
 697 /*
 698  * a small number of entries is fine, not going to be performance critical.
 699  * basically we just need to survive
 700  */
 701 #define BIO_SPLIT_ENTRIES 2
 702
 703 #if defined(CONFIG_BLK_DEV_INTEGRITY)
 704
 705 #define bip_for_each_vec(bvl, bip, iter)                                \
 706         for_each_bvec(bvl, (bip)->bip_vec, iter, (bip)->bip_iter)
 707
 708 #define bio_for_each_integrity_vec(_bvl, _bio, _iter)                   \
 709         for_each_bio(_bio)                                              \
 710                 bip_for_each_vec(_bvl, _bio->bi_integrity, _iter)
 711
 712 extern struct bio_integrity_payload *bio_integrity_alloc(struct bio *, gfp_t, unsigned int);
 713 extern void bio_integrity_free(struct bio *);
 714 extern int bio_integrity_add_page(struct bio *, struct page *, unsigned int, unsigned int);
 715 extern bool bio_integrity_enabled(struct bio *bio);
 716 extern int bio_integrity_prep(struct bio *);
 717 extern void bio_integrity_endio(struct bio *);
 718 extern void bio_integrity_advance(struct bio *, unsigned int);
 719 extern void bio_integrity_trim(struct bio *, unsigned int, unsigned int);
 720 extern int bio_integrity_clone(struct bio *, struct bio *, gfp_t);
 721 extern int bioset_integrity_create(struct bio_set *, int);
 722 extern void bioset_integrity_free(struct bio_set *);
 723 extern void bio_integrity_init(void);
 724
 725 #else /* CONFIG_BLK_DEV_INTEGRITY */
 726
 727 static inline void *bio_integrity(struct bio *bio)
 728 {
 729         return NULL;
 730 }
 731
 732 static inline bool bio_integrity_enabled(struct bio *bio)
 733 {
 734         return false;
 735 }
 736
 737 static inline int bioset_integrity_create(struct bio_set *bs, int pool_size)
 738 {
 739         return 0;
 740 }
 741
 742 static inline void bioset_integrity_free (struct bio_set *bs)
 743 {
 744         return;
 745 }
 746
 747 static inline int bio_integrity_prep(struct bio *bio)
 748 {
 749         return 0;
 750 }
 751
 752 static inline void bio_integrity_free(struct bio *bio)
 753 {
 754         return;
 755 }
 756
 757 static inline int bio_integrity_clone(struct bio *bio, struct bio *bio_src,
 758                                       gfp_t gfp_mask)
 759 {
 760         return 0;
 761 }
 762
 763 static inline void bio_integrity_advance(struct bio *bio,
 764                                          unsigned int bytes_done)
 765 {
 766         return;
 767 }
 768
 769 static inline void bio_integrity_trim(struct bio *bio, unsigned int offset,
 770                                       unsigned int sectors)
 771 {
 772         return;
 773 }
 774
 775 static inline void bio_integrity_init(void)
 776 {
 777         return;
 778 }
 779
 780 static inline bool bio_integrity_flagged(struct bio *bio, enum bip_flags flag)
 781 {
 782         return false;
 783 }
 784
 785 static inline void *bio_integrity_alloc(struct bio * bio, gfp_t gfp,
 786                                                                 unsigned int nr)
 787 {
 788         return ERR_PTR(-EINVAL);
 789 }
 790
 791 static inline int bio_integrity_add_page(struct bio *bio, struct page *page,
 792                                         unsigned int len, unsigned int offset)
 793 {
 794         return 0;
 795 }
 796
 797 #endif /* CONFIG_BLK_DEV_INTEGRITY */
 798
 799 #endif /* CONFIG_BLOCK */
 800 #endif /* __LINUX_BIO_H */