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