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  * queues that have highmem support enabled may still need to revert to
 133  * PIO transfers occasionally and thus map high pages temporarily. For
 134  * permanent PIO fall back, user is probably better off disabling highmem
 135  * I/O completely on that queue (see ide-dma for example)
 136  */
 137 #define __bio_kmap_atomic(bio, iter)                            \
 138         (kmap_atomic(bio_iter_iovec((bio), (iter)).bv_page) +   \
 139                 bio_iter_iovec((bio), (iter)).bv_offset)
 140
 141 #define __bio_kunmap_atomic(addr)       kunmap_atomic(addr)
 142
 143 /*
 144  * merge helpers etc
 145  */
 146
 147 /* Default implementation of BIOVEC_PHYS_MERGEABLE */
 148 #define __BIOVEC_PHYS_MERGEABLE(vec1, vec2)     \
 149         ((bvec_to_phys((vec1)) + (vec1)->bv_len) == bvec_to_phys((vec2)))
 150
 151 /*
 152  * allow arch override, for eg virtualized architectures (put in asm/io.h)
 153  */
 154 #ifndef BIOVEC_PHYS_MERGEABLE
 155 #define BIOVEC_PHYS_MERGEABLE(vec1, vec2)       \
 156         __BIOVEC_PHYS_MERGEABLE(vec1, vec2)
 157 #endif
 158
 159 #define __BIO_SEG_BOUNDARY(addr1, addr2, mask) \
 160         (((addr1) | (mask)) == (((addr2) - 1) | (mask)))
 161 #define BIOVEC_SEG_BOUNDARY(q, b1, b2) \
 162         __BIO_SEG_BOUNDARY(bvec_to_phys((b1)), bvec_to_phys((b2)) + (b2)->bv_len, queue_segment_boundary((q)))
 163
 164 /*
 165  * drivers should _never_ use the all version - the bio may have been split
 166  * before it got to the driver and the driver won't own all of it
 167  */
 168 #define bio_for_each_segment_all(bvl, bio, i)                           \
 169         for (i = 0, bvl = (bio)->bi_io_vec; i < (bio)->bi_vcnt; i++, bvl++)
 170
 171 static inline void bio_advance_iter(struct bio *bio, struct bvec_iter *iter,
 172                                     unsigned bytes)
 173 {
 174         iter->bi_sector += bytes >> 9;
 175
 176         if (bio_no_advance_iter(bio)) {
 177                 iter->bi_size -= bytes;
 178                 iter->bi_done += bytes;
 179         } else {
 180                 bvec_iter_advance(bio->bi_io_vec, iter, bytes);
 181                 /* TODO: It is reasonable to complete bio with error here. */
 182         }
 183 }
 184
 185 static inline bool bio_rewind_iter(struct bio *bio, struct bvec_iter *iter,
 186                 unsigned int bytes)
 187 {
 188         iter->bi_sector -= bytes >> 9;
 189
 190         if (bio_no_advance_iter(bio)) {
 191                 iter->bi_size += bytes;
 192                 iter->bi_done -= bytes;
 193                 return true;
 194         }
 195
 196         return bvec_iter_rewind(bio->bi_io_vec, iter, bytes);
 197 }
 198
 199 #define __bio_for_each_segment(bvl, bio, iter, start)                   \
 200         for (iter = (start);                                            \
 201              (iter).bi_size &&                                          \
 202                 ((bvl = bio_iter_iovec((bio), (iter))), 1);             \
 203              bio_advance_iter((bio), &(iter), (bvl).bv_len))
 204
 205 #define bio_for_each_segment(bvl, bio, iter)                            \
 206         __bio_for_each_segment(bvl, bio, iter, (bio)->bi_iter)
 207
 208 #define bio_iter_last(bvec, iter) ((iter).bi_size == (bvec).bv_len)
 209
 210 static inline unsigned bio_segments(struct bio *bio)
 211 {
 212         unsigned segs = 0;
 213         struct bio_vec bv;
 214         struct bvec_iter iter;
 215
 216         /*
 217          * We special case discard/write same/write zeroes, because they
 218          * interpret bi_size differently:
 219          */
 220
 221         switch (bio_op(bio)) {
 222         case REQ_OP_DISCARD:
 223         case REQ_OP_SECURE_ERASE:
 224         case REQ_OP_WRITE_ZEROES:
 225                 return 0;
 226         case REQ_OP_WRITE_SAME:
 227                 return 1;
 228         default:
 229                 break;
 230         }
 231
 232         bio_for_each_segment(bv, bio, iter)
 233                 segs++;
 234
 235         return segs;
 236 }
 237
 238 /*
 239  * get a reference to a bio, so it won't disappear. the intended use is
 240  * something like:
 241  *
 242  * bio_get(bio);
 243  * submit_bio(rw, bio);
 244  * if (bio->bi_flags ...)
 245  *      do_something
 246  * bio_put(bio);
 247  *
 248  * without the bio_get(), it could potentially complete I/O before submit_bio
 249  * returns. and then bio would be freed memory when if (bio->bi_flags ...)
 250  * runs
 251  */
 252 static inline void bio_get(struct bio *bio)
 253 {
 254         bio->bi_flags |= (1 << BIO_REFFED);
 255         smp_mb__before_atomic();
 256         atomic_inc(&bio->__bi_cnt);
 257 }
 258
 259 static inline void bio_cnt_set(struct bio *bio, unsigned int count)
 260 {
 261         if (count != 1) {
 262                 bio->bi_flags |= (1 << BIO_REFFED);
 263                 smp_mb__before_atomic();
 264         }
 265         atomic_set(&bio->__bi_cnt, count);
 266 }
 267
 268 static inline bool bio_flagged(struct bio *bio, unsigned int bit)
 269 {
 270         return (bio->bi_flags & (1U << bit)) != 0;
 271 }
 272
 273 static inline void bio_set_flag(struct bio *bio, unsigned int bit)
 274 {
 275         bio->bi_flags |= (1U << bit);
 276 }
 277
 278 static inline void bio_clear_flag(struct bio *bio, unsigned int bit)
 279 {
 280         bio->bi_flags &= ~(1U << bit);
 281 }
 282
 283 static inline void bio_get_first_bvec(struct bio *bio, struct bio_vec *bv)
 284 {
 285         *bv = bio_iovec(bio);
 286 }
 287
 288 static inline void bio_get_last_bvec(struct bio *bio, struct bio_vec *bv)
 289 {
 290         struct bvec_iter iter = bio->bi_iter;
 291         int idx;
 292
 293         if (unlikely(!bio_multiple_segments(bio))) {
 294                 *bv = bio_iovec(bio);
 295                 return;
 296         }
 297
 298         bio_advance_iter(bio, &iter, iter.bi_size);
 299
 300         if (!iter.bi_bvec_done)
 301                 idx = iter.bi_idx - 1;
 302         else    /* in the middle of bvec */
 303                 idx = iter.bi_idx;
 304
 305         *bv = bio->bi_io_vec[idx];
 306
 307         /*
 308          * iter.bi_bvec_done records actual length of the last bvec
 309          * if this bio ends in the middle of one io vector
 310          */
 311         if (iter.bi_bvec_done)
 312                 bv->bv_len = iter.bi_bvec_done;
 313 }
 314
 315 enum bip_flags {
 316         BIP_BLOCK_INTEGRITY     = 1 << 0, /* block layer owns integrity data */
 317         BIP_MAPPED_INTEGRITY    = 1 << 1, /* ref tag has been remapped */
 318         BIP_CTRL_NOCHECK        = 1 << 2, /* disable HBA integrity checking */
 319         BIP_DISK_NOCHECK        = 1 << 3, /* disable disk integrity checking */
 320         BIP_IP_CHECKSUM         = 1 << 4, /* IP checksum */
 321 };
 322
 323 /*
 324  * bio integrity payload
 325  */
 326 struct bio_integrity_payload {
 327         struct bio              *bip_bio;       /* parent bio */
 328
 329         struct bvec_iter        bip_iter;
 330
 331         unsigned short          bip_slab;       /* slab the bip came from */
 332         unsigned short          bip_vcnt;       /* # of integrity bio_vecs */
 333         unsigned short          bip_max_vcnt;   /* integrity bio_vec slots */
 334         unsigned short          bip_flags;      /* control flags */
 335
 336         struct work_struct      bip_work;       /* I/O completion */
 337
 338         struct bio_vec          *bip_vec;
 339         struct bio_vec          bip_inline_vecs[0];/* embedded bvec array */
 340 };
 341
 342 #if defined(CONFIG_BLK_DEV_INTEGRITY)
 343
 344 static inline struct bio_integrity_payload *bio_integrity(struct bio *bio)
 345 {
 346         if (bio->bi_opf & REQ_INTEGRITY)
 347                 return bio->bi_integrity;
 348
 349         return NULL;
 350 }
 351
 352 static inline bool bio_integrity_flagged(struct bio *bio, enum bip_flags flag)
 353 {
 354         struct bio_integrity_payload *bip = bio_integrity(bio);
 355
 356         if (bip)
 357                 return bip->bip_flags & flag;
 358
 359         return false;
 360 }
 361
 362 static inline sector_t bip_get_seed(struct bio_integrity_payload *bip)
 363 {
 364         return bip->bip_iter.bi_sector;
 365 }
 366
 367 static inline void bip_set_seed(struct bio_integrity_payload *bip,
 368                                 sector_t seed)
 369 {
 370         bip->bip_iter.bi_sector = seed;
 371 }
 372
 373 #endif /* CONFIG_BLK_DEV_INTEGRITY */
 374
 375 extern void bio_trim(struct bio *bio, int offset, int size);
 376 extern struct bio *bio_split(struct bio *bio, int sectors,
 377                              gfp_t gfp, struct bio_set *bs);
 378
 379 /**
 380  * bio_next_split - get next @sectors from a bio, splitting if necessary
 381  * @bio:        bio to split
 382  * @sectors:    number of sectors to split from the front of @bio
 383  * @gfp:        gfp mask
 384  * @bs:         bio set to allocate from
 385  *
 386  * Returns a bio representing the next @sectors of @bio - if the bio is smaller
 387  * than @sectors, returns the original bio unchanged.
 388  */
 389 static inline struct bio *bio_next_split(struct bio *bio, int sectors,
 390                                          gfp_t gfp, struct bio_set *bs)
 391 {
 392         if (sectors >= bio_sectors(bio))
 393                 return bio;
 394
 395         return bio_split(bio, sectors, gfp, bs);
 396 }
 397
 398 extern struct bio_set *bioset_create(unsigned int, unsigned int, int flags);
 399 enum {
 400         BIOSET_NEED_BVECS = BIT(0),
 401         BIOSET_NEED_RESCUER = BIT(1),
 402 };
 403 extern void bioset_free(struct bio_set *);
 404 extern mempool_t *biovec_create_pool(int pool_entries);
 405
 406 extern struct bio *bio_alloc_bioset(gfp_t, unsigned int, struct bio_set *);
 407 extern void bio_put(struct bio *);
 408
 409 extern void __bio_clone_fast(struct bio *, struct bio *);
 410 extern struct bio *bio_clone_fast(struct bio *, gfp_t, struct bio_set *);
 411 extern struct bio *bio_clone_bioset(struct bio *, gfp_t, struct bio_set *bs);
 412
 413 extern struct bio_set *fs_bio_set;
 414
 415 static inline struct bio *bio_alloc(gfp_t gfp_mask, unsigned int nr_iovecs)
 416 {
 417         return bio_alloc_bioset(gfp_mask, nr_iovecs, fs_bio_set);
 418 }
 419
 420 static inline struct bio *bio_kmalloc(gfp_t gfp_mask, unsigned int nr_iovecs)
 421 {
 422         return bio_alloc_bioset(gfp_mask, nr_iovecs, NULL);
 423 }
 424
 425 static inline struct bio *bio_clone_kmalloc(struct bio *bio, gfp_t gfp_mask)
 426 {
 427         return bio_clone_bioset(bio, gfp_mask, NULL);
 428
 429 }
 430
 431 extern blk_qc_t submit_bio(struct bio *);
 432
 433 extern void bio_endio(struct bio *);
 434
 435 static inline void bio_io_error(struct bio *bio)
 436 {
 437         bio->bi_status = BLK_STS_IOERR;
 438         bio_endio(bio);
 439 }
 440
 441 static inline void bio_wouldblock_error(struct bio *bio)
 442 {
 443         bio->bi_status = BLK_STS_AGAIN;
 444         bio_endio(bio);
 445 }
 446
 447 struct request_queue;
 448 extern int bio_phys_segments(struct request_queue *, struct bio *);
 449
 450 extern int submit_bio_wait(struct bio *bio);
 451 extern void bio_advance(struct bio *, unsigned);
 452
 453 extern void bio_init(struct bio *bio, struct bio_vec *table,
 454                      unsigned short max_vecs);
 455 extern void bio_uninit(struct bio *);
 456 extern void bio_reset(struct bio *);
 457 void bio_chain(struct bio *, struct bio *);
 458
 459 extern int bio_add_page(struct bio *, struct page *, unsigned int,unsigned int);
 460 extern int bio_add_pc_page(struct request_queue *, struct bio *, struct page *,
 461                            unsigned int, unsigned int);
 462 int bio_iov_iter_get_pages(struct bio *bio, struct iov_iter *iter);
 463 struct rq_map_data;
 464 extern struct bio *bio_map_user_iov(struct request_queue *,
 465                                     const struct iov_iter *, gfp_t);
 466 extern void bio_unmap_user(struct bio *);
 467 extern struct bio *bio_map_kern(struct request_queue *, void *, unsigned int,
 468                                 gfp_t);
 469 extern struct bio *bio_copy_kern(struct request_queue *, void *, unsigned int,
 470                                  gfp_t, int);
 471 extern void bio_set_pages_dirty(struct bio *bio);
 472 extern void bio_check_pages_dirty(struct bio *bio);
 473
 474 void generic_start_io_acct(struct request_queue *q, int rw,
 475                                 unsigned long sectors, struct hd_struct *part);
 476 void generic_end_io_acct(struct request_queue *q, int rw,
 477                                 struct hd_struct *part,
 478                                 unsigned long start_time);
 479
 480 #ifndef ARCH_IMPLEMENTS_FLUSH_DCACHE_PAGE
 481 # error "You should define ARCH_IMPLEMENTS_FLUSH_DCACHE_PAGE for your platform"
 482 #endif
 483 #if ARCH_IMPLEMENTS_FLUSH_DCACHE_PAGE
 484 extern void bio_flush_dcache_pages(struct bio *bi);
 485 #else
 486 static inline void bio_flush_dcache_pages(struct bio *bi)
 487 {
 488 }
 489 #endif
 490
 491 extern void bio_copy_data(struct bio *dst, struct bio *src);
 492 extern int bio_alloc_pages(struct bio *bio, gfp_t gfp);
 493 extern void bio_free_pages(struct bio *bio);
 494
 495 extern struct bio *bio_copy_user_iov(struct request_queue *,
 496                                      struct rq_map_data *,
 497                                      const struct iov_iter *,
 498                                      gfp_t);
 499 extern int bio_uncopy_user(struct bio *);
 500 void zero_fill_bio(struct bio *bio);
 501 extern struct bio_vec *bvec_alloc(gfp_t, int, unsigned long *, mempool_t *);
 502 extern void bvec_free(mempool_t *, struct bio_vec *, unsigned int);
 503 extern unsigned int bvec_nr_vecs(unsigned short idx);
 504
 505 #define bio_set_dev(bio, bdev)                  \
 506 do {                                            \
 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 #define bio_devname(bio, buf) \
 521         __bdevname(bio_dev(bio), (buf))
 522
 523 #ifdef CONFIG_BLK_CGROUP
 524 int bio_associate_blkcg(struct bio *bio, struct cgroup_subsys_state *blkcg_css);
 525 int bio_associate_current(struct bio *bio);
 526 void bio_disassociate_task(struct bio *bio);
 527 void bio_clone_blkcg_association(struct bio *dst, struct bio *src);
 528 #else   /* CONFIG_BLK_CGROUP */
 529 static inline int bio_associate_blkcg(struct bio *bio,
 530                         struct cgroup_subsys_state *blkcg_css) { return 0; }
 531 static inline int bio_associate_current(struct bio *bio) { return -ENOENT; }
 532 static inline void bio_disassociate_task(struct bio *bio) { }
 533 static inline void bio_clone_blkcg_association(struct bio *dst,
 534                         struct bio *src) { }
 535 #endif  /* CONFIG_BLK_CGROUP */
 536
 537 #ifdef CONFIG_HIGHMEM
 538 /*
 539  * remember never ever reenable interrupts between a bvec_kmap_irq and
 540  * bvec_kunmap_irq!
 541  */
 542 static inline char *bvec_kmap_irq(struct bio_vec *bvec, unsigned long *flags)
 543 {
 544         unsigned long addr;
 545
 546         /*
 547          * might not be a highmem page, but the preempt/irq count
 548          * balancing is a lot nicer this way
 549          */
 550         local_irq_save(*flags);
 551         addr = (unsigned long) kmap_atomic(bvec->bv_page);
 552
 553         BUG_ON(addr & ~PAGE_MASK);
 554
 555         return (char *) addr + bvec->bv_offset;
 556 }
 557
 558 static inline void bvec_kunmap_irq(char *buffer, unsigned long *flags)
 559 {
 560         unsigned long ptr = (unsigned long) buffer & PAGE_MASK;
 561
 562         kunmap_atomic((void *) ptr);
 563         local_irq_restore(*flags);
 564 }
 565
 566 #else
 567 static inline char *bvec_kmap_irq(struct bio_vec *bvec, unsigned long *flags)
 568 {
 569         return page_address(bvec->bv_page) + bvec->bv_offset;
 570 }
 571
 572 static inline void bvec_kunmap_irq(char *buffer, unsigned long *flags)
 573 {
 574         *flags = 0;
 575 }
 576 #endif
 577
 578 static inline char *__bio_kmap_irq(struct bio *bio, struct bvec_iter iter,
 579                                    unsigned long *flags)
 580 {
 581         return bvec_kmap_irq(&bio_iter_iovec(bio, iter), flags);
 582 }
 583 #define __bio_kunmap_irq(buf, flags)    bvec_kunmap_irq(buf, flags)
 584
 585 #define bio_kmap_irq(bio, flags) \
 586         __bio_kmap_irq((bio), (bio)->bi_iter, (flags))
 587 #define bio_kunmap_irq(buf,flags)       __bio_kunmap_irq(buf, flags)
 588
 589 /*
 590  * BIO list management for use by remapping drivers (e.g. DM or MD) and loop.
 591  *
 592  * A bio_list anchors a singly-linked list of bios chained through the bi_next
 593  * member of the bio.  The bio_list also caches the last list member to allow
 594  * fast access to the tail.
 595  */
 596 struct bio_list {
 597         struct bio *head;
 598         struct bio *tail;
 599 };
 600
 601 static inline int bio_list_empty(const struct bio_list *bl)
 602 {
 603         return bl->head == NULL;
 604 }
 605
 606 static inline void bio_list_init(struct bio_list *bl)
 607 {
 608         bl->head = bl->tail = NULL;
 609 }
 610
 611 #define BIO_EMPTY_LIST  { NULL, NULL }
 612
 613 #define bio_list_for_each(bio, bl) \
 614         for (bio = (bl)->head; bio; bio = bio->bi_next)
 615
 616 static inline unsigned bio_list_size(const struct bio_list *bl)
 617 {
 618         unsigned sz = 0;
 619         struct bio *bio;
 620
 621         bio_list_for_each(bio, bl)
 622                 sz++;
 623
 624         return sz;
 625 }
 626
 627 static inline void bio_list_add(struct bio_list *bl, struct bio *bio)
 628 {
 629         bio->bi_next = NULL;
 630
 631         if (bl->tail)
 632                 bl->tail->bi_next = bio;
 633         else
 634                 bl->head = bio;
 635
 636         bl->tail = bio;
 637 }
 638
 639 static inline void bio_list_add_head(struct bio_list *bl, struct bio *bio)
 640 {
 641         bio->bi_next = bl->head;
 642
 643         bl->head = bio;
 644
 645         if (!bl->tail)
 646                 bl->tail = bio;
 647 }
 648
 649 static inline void bio_list_merge(struct bio_list *bl, struct bio_list *bl2)
 650 {
 651         if (!bl2->head)
 652                 return;
 653
 654         if (bl->tail)
 655                 bl->tail->bi_next = bl2->head;
 656         else
 657                 bl->head = bl2->head;
 658
 659         bl->tail = bl2->tail;
 660 }
 661
 662 static inline void bio_list_merge_head(struct bio_list *bl,
 663                                        struct bio_list *bl2)
 664 {
 665         if (!bl2->head)
 666                 return;
 667
 668         if (bl->head)
 669                 bl2->tail->bi_next = bl->head;
 670         else
 671                 bl->tail = bl2->tail;
 672
 673         bl->head = bl2->head;
 674 }
 675
 676 static inline struct bio *bio_list_peek(struct bio_list *bl)
 677 {
 678         return bl->head;
 679 }
 680
 681 static inline struct bio *bio_list_pop(struct bio_list *bl)
 682 {
 683         struct bio *bio = bl->head;
 684
 685         if (bio) {
 686                 bl->head = bl->head->bi_next;
 687                 if (!bl->head)
 688                         bl->tail = NULL;
 689
 690                 bio->bi_next = NULL;
 691         }
 692
 693         return bio;
 694 }
 695
 696 static inline struct bio *bio_list_get(struct bio_list *bl)
 697 {
 698         struct bio *bio = bl->head;
 699
 700         bl->head = bl->tail = NULL;
 701
 702         return bio;
 703 }
 704
 705 /*
 706  * Increment chain count for the bio. Make sure the CHAIN flag update
 707  * is visible before the raised count.
 708  */
 709 static inline void bio_inc_remaining(struct bio *bio)
 710 {
 711         bio_set_flag(bio, BIO_CHAIN);
 712         smp_mb__before_atomic();
 713         atomic_inc(&bio->__bi_remaining);
 714 }
 715
 716 /*
 717  * bio_set is used to allow other portions of the IO system to
 718  * allocate their own private memory pools for bio and iovec structures.
 719  * These memory pools in turn all allocate from the bio_slab
 720  * and the bvec_slabs[].
 721  */
 722 #define BIO_POOL_SIZE 2
 723
 724 struct bio_set {
 725         struct kmem_cache *bio_slab;
 726         unsigned int front_pad;
 727
 728         mempool_t *bio_pool;
 729         mempool_t *bvec_pool;
 730 #if defined(CONFIG_BLK_DEV_INTEGRITY)
 731         mempool_t *bio_integrity_pool;
 732         mempool_t *bvec_integrity_pool;
 733 #endif
 734
 735         /*
 736          * Deadlock avoidance for stacking block drivers: see comments in
 737          * bio_alloc_bioset() for details
 738          */
 739         spinlock_t              rescue_lock;
 740         struct bio_list         rescue_list;
 741         struct work_struct      rescue_work;
 742         struct workqueue_struct *rescue_workqueue;
 743 };
 744
 745 struct biovec_slab {
 746         int nr_vecs;
 747         char *name;
 748         struct kmem_cache *slab;
 749 };
 750
 751 /*
 752  * a small number of entries is fine, not going to be performance critical.
 753  * basically we just need to survive
 754  */
 755 #define BIO_SPLIT_ENTRIES 2
 756
 757 #if defined(CONFIG_BLK_DEV_INTEGRITY)
 758
 759 #define bip_for_each_vec(bvl, bip, iter)                                \
 760         for_each_bvec(bvl, (bip)->bip_vec, iter, (bip)->bip_iter)
 761
 762 #define bio_for_each_integrity_vec(_bvl, _bio, _iter)                   \
 763         for_each_bio(_bio)                                              \
 764                 bip_for_each_vec(_bvl, _bio->bi_integrity, _iter)
 765
 766 extern struct bio_integrity_payload *bio_integrity_alloc(struct bio *, gfp_t, unsigned int);
 767 extern int bio_integrity_add_page(struct bio *, struct page *, unsigned int, unsigned int);
 768 extern bool bio_integrity_prep(struct bio *);
 769 extern void bio_integrity_advance(struct bio *, unsigned int);
 770 extern void bio_integrity_trim(struct bio *);
 771 extern int bio_integrity_clone(struct bio *, struct bio *, gfp_t);
 772 extern int bioset_integrity_create(struct bio_set *, int);
 773 extern void bioset_integrity_free(struct bio_set *);
 774 extern void bio_integrity_init(void);
 775
 776 #else /* CONFIG_BLK_DEV_INTEGRITY */
 777
 778 static inline void *bio_integrity(struct bio *bio)
 779 {
 780         return NULL;
 781 }
 782
 783 static inline int bioset_integrity_create(struct bio_set *bs, int pool_size)
 784 {
 785         return 0;
 786 }
 787
 788 static inline void bioset_integrity_free (struct bio_set *bs)
 789 {
 790         return;
 791 }
 792
 793 static inline bool bio_integrity_prep(struct bio *bio)
 794 {
 795         return true;
 796 }
 797
 798 static inline int bio_integrity_clone(struct bio *bio, struct bio *bio_src,
 799                                       gfp_t gfp_mask)
 800 {
 801         return 0;
 802 }
 803
 804 static inline void bio_integrity_advance(struct bio *bio,
 805                                          unsigned int bytes_done)
 806 {
 807         return;
 808 }
 809
 810 static inline void bio_integrity_trim(struct bio *bio)
 811 {
 812         return;
 813 }
 814
 815 static inline void bio_integrity_init(void)
 816 {
 817         return;
 818 }
 819
 820 static inline bool bio_integrity_flagged(struct bio *bio, enum bip_flags flag)
 821 {
 822         return false;
 823 }
 824
 825 static inline void *bio_integrity_alloc(struct bio * bio, gfp_t gfp,
 826                                                                 unsigned int nr)
 827 {
 828         return ERR_PTR(-EINVAL);
 829 }
 830
 831 static inline int bio_integrity_add_page(struct bio *bio, struct page *page,
 832                                         unsigned int len, unsigned int offset)
 833 {
 834         return 0;
 835 }
 836
 837 #endif /* CONFIG_BLK_DEV_INTEGRITY */
 838
 839 #endif /* CONFIG_BLOCK */
 840 #endif /* __LINUX_BIO_H */