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