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 #define BIO_MAX_SIZE            (BIO_MAX_PAGES << PAGE_CACHE_SHIFT)
  45 #define BIO_MAX_SECTORS         (BIO_MAX_SIZE >> 9)
  46
  47 /*
  48  * upper 16 bits of bi_rw define the io priority of this bio
  49  */
  50 #define BIO_PRIO_SHIFT  (8 * sizeof(unsigned long) - IOPRIO_BITS)
  51 #define bio_prio(bio)   ((bio)->bi_rw >> BIO_PRIO_SHIFT)
  52 #define bio_prio_valid(bio)     ioprio_valid(bio_prio(bio))
  53
  54 #define bio_set_prio(bio, prio)         do {                    \
  55         WARN_ON(prio >= (1 << IOPRIO_BITS));                    \
  56         (bio)->bi_rw &= ((1UL << BIO_PRIO_SHIFT) - 1);          \
  57         (bio)->bi_rw |= ((unsigned long) (prio) << BIO_PRIO_SHIFT);     \
  58 } while (0)
  59
  60 /*
  61  * various member access, note that bio_data should of course not be used
  62  * on highmem page vectors
  63  */
  64 #define bio_iovec_idx(bio, idx) (&((bio)->bi_io_vec[(idx)]))
  65 #define bio_iovec(bio)          bio_iovec_idx((bio), (bio)->bi_idx)
  66 #define bio_page(bio)           bio_iovec((bio))->bv_page
  67 #define bio_offset(bio)         bio_iovec((bio))->bv_offset
  68 #define bio_segments(bio)       ((bio)->bi_vcnt - (bio)->bi_idx)
  69 #define bio_sectors(bio)        ((bio)->bi_size >> 9)
  70
  71 static inline unsigned int bio_cur_bytes(struct bio *bio)
  72 {
  73         if (bio->bi_vcnt)
  74                 return bio_iovec(bio)->bv_len;
  75         else /* dataless requests such as discard */
  76                 return bio->bi_size;
  77 }
  78
  79 static inline void *bio_data(struct bio *bio)
  80 {
  81         if (bio->bi_vcnt)
  82                 return page_address(bio_page(bio)) + bio_offset(bio);
  83
  84         return NULL;
  85 }
  86
  87 static inline int bio_has_allocated_vec(struct bio *bio)
  88 {
  89         return bio->bi_io_vec && bio->bi_io_vec != bio->bi_inline_vecs;
  90 }
  91
  92 /*
  93  * will die
  94  */
  95 #define bio_to_phys(bio)        (page_to_phys(bio_page((bio))) + (unsigned long) bio_offset((bio)))
  96 #define bvec_to_phys(bv)        (page_to_phys((bv)->bv_page) + (unsigned long) (bv)->bv_offset)
  97
  98 /*
  99  * queues that have highmem support enabled may still need to revert to
 100  * PIO transfers occasionally and thus map high pages temporarily. For
 101  * permanent PIO fall back, user is probably better off disabling highmem
 102  * I/O completely on that queue (see ide-dma for example)
 103  */
 104 #define __bio_kmap_atomic(bio, idx, kmtype)                             \
 105         (kmap_atomic(bio_iovec_idx((bio), (idx))->bv_page) +    \
 106                 bio_iovec_idx((bio), (idx))->bv_offset)
 107
 108 #define __bio_kunmap_atomic(addr, kmtype) kunmap_atomic(addr)
 109
 110 /*
 111  * merge helpers etc
 112  */
 113
 114 #define __BVEC_END(bio)         bio_iovec_idx((bio), (bio)->bi_vcnt - 1)
 115 #define __BVEC_START(bio)       bio_iovec_idx((bio), (bio)->bi_idx)
 116
 117 /* Default implementation of BIOVEC_PHYS_MERGEABLE */
 118 #define __BIOVEC_PHYS_MERGEABLE(vec1, vec2)     \
 119         ((bvec_to_phys((vec1)) + (vec1)->bv_len) == bvec_to_phys((vec2)))
 120
 121 /*
 122  * allow arch override, for eg virtualized architectures (put in asm/io.h)
 123  */
 124 #ifndef BIOVEC_PHYS_MERGEABLE
 125 #define BIOVEC_PHYS_MERGEABLE(vec1, vec2)       \
 126         __BIOVEC_PHYS_MERGEABLE(vec1, vec2)
 127 #endif
 128
 129 #define __BIO_SEG_BOUNDARY(addr1, addr2, mask) \
 130         (((addr1) | (mask)) == (((addr2) - 1) | (mask)))
 131 #define BIOVEC_SEG_BOUNDARY(q, b1, b2) \
 132         __BIO_SEG_BOUNDARY(bvec_to_phys((b1)), bvec_to_phys((b2)) + (b2)->bv_len, queue_segment_boundary((q)))
 133 #define BIO_SEG_BOUNDARY(q, b1, b2) \
 134         BIOVEC_SEG_BOUNDARY((q), __BVEC_END((b1)), __BVEC_START((b2)))
 135
 136 #define bio_io_error(bio) bio_endio((bio), -EIO)
 137
 138 /*
 139  * drivers should not use the __ version unless they _really_ want to
 140  * run through the entire bio and not just pending pieces
 141  */
 142 #define __bio_for_each_segment(bvl, bio, i, start_idx)                  \
 143         for (bvl = bio_iovec_idx((bio), (start_idx)), i = (start_idx);  \
 144              i < (bio)->bi_vcnt;                                        \
 145              bvl++, i++)
 146
 147 #define bio_for_each_segment(bvl, bio, i)                               \
 148         __bio_for_each_segment(bvl, bio, i, (bio)->bi_idx)
 149
 150 /*
 151  * get a reference to a bio, so it won't disappear. the intended use is
 152  * something like:
 153  *
 154  * bio_get(bio);
 155  * submit_bio(rw, bio);
 156  * if (bio->bi_flags ...)
 157  *      do_something
 158  * bio_put(bio);
 159  *
 160  * without the bio_get(), it could potentially complete I/O before submit_bio
 161  * returns. and then bio would be freed memory when if (bio->bi_flags ...)
 162  * runs
 163  */
 164 #define bio_get(bio)    atomic_inc(&(bio)->bi_cnt)
 165
 166 #if defined(CONFIG_BLK_DEV_INTEGRITY)
 167 /*
 168  * bio integrity payload
 169  */
 170 struct bio_integrity_payload {
 171         struct bio              *bip_bio;       /* parent bio */
 172
 173         sector_t                bip_sector;     /* virtual start sector */
 174
 175         void                    *bip_buf;       /* generated integrity data */
 176         bio_end_io_t            *bip_end_io;    /* saved I/O completion fn */
 177
 178         unsigned int            bip_size;
 179
 180         unsigned short          bip_slab;       /* slab the bip came from */
 181         unsigned short          bip_vcnt;       /* # of integrity bio_vecs */
 182         unsigned short          bip_idx;        /* current bip_vec index */
 183
 184         struct work_struct      bip_work;       /* I/O completion */
 185         struct bio_vec          bip_vec[0];     /* embedded bvec array */
 186 };
 187 #endif /* CONFIG_BLK_DEV_INTEGRITY */
 188
 189 /*
 190  * A bio_pair is used when we need to split a bio.
 191  * This can only happen for a bio that refers to just one
 192  * page of data, and in the unusual situation when the
 193  * page crosses a chunk/device boundary
 194  *
 195  * The address of the master bio is stored in bio1.bi_private
 196  * The address of the pool the pair was allocated from is stored
 197  *   in bio2.bi_private
 198  */
 199 struct bio_pair {
 200         struct bio                      bio1, bio2;
 201         struct bio_vec                  bv1, bv2;
 202 #if defined(CONFIG_BLK_DEV_INTEGRITY)
 203         struct bio_integrity_payload    bip1, bip2;
 204         struct bio_vec                  iv1, iv2;
 205 #endif
 206         atomic_t                        cnt;
 207         int                             error;
 208 };
 209 extern struct bio_pair *bio_split(struct bio *bi, int first_sectors);
 210 extern void bio_pair_release(struct bio_pair *dbio);
 211
 212 extern struct bio_set *bioset_create(unsigned int, unsigned int);
 213 extern void bioset_free(struct bio_set *);
 214
 215 extern struct bio *bio_alloc(gfp_t, unsigned int);
 216 extern struct bio *bio_kmalloc(gfp_t, unsigned int);
 217 extern struct bio *bio_alloc_bioset(gfp_t, int, struct bio_set *);
 218 extern void bio_put(struct bio *);
 219 extern void bio_free(struct bio *, struct bio_set *);
 220
 221 extern void bio_endio(struct bio *, int);
 222 struct request_queue;
 223 extern int bio_phys_segments(struct request_queue *, struct bio *);
 224
 225 extern void __bio_clone(struct bio *, struct bio *);
 226 extern struct bio *bio_clone(struct bio *, gfp_t);
 227
 228 extern void bio_init(struct bio *);
 229 extern void bio_reset(struct bio *);
 230
 231 extern int bio_add_page(struct bio *, struct page *, unsigned int,unsigned int);
 232 extern int bio_add_pc_page(struct request_queue *, struct bio *, struct page *,
 233                            unsigned int, unsigned int);
 234 extern int bio_get_nr_vecs(struct block_device *);
 235 extern sector_t bio_sector_offset(struct bio *, unsigned short, unsigned int);
 236 extern struct bio *bio_map_user(struct request_queue *, struct block_device *,
 237                                 unsigned long, unsigned int, int, gfp_t);
 238 struct sg_iovec;
 239 struct rq_map_data;
 240 extern struct bio *bio_map_user_iov(struct request_queue *,
 241                                     struct block_device *,
 242                                     struct sg_iovec *, int, int, gfp_t);
 243 extern void bio_unmap_user(struct bio *);
 244 extern struct bio *bio_map_kern(struct request_queue *, void *, unsigned int,
 245                                 gfp_t);
 246 extern struct bio *bio_copy_kern(struct request_queue *, void *, unsigned int,
 247                                  gfp_t, int);
 248 extern void bio_set_pages_dirty(struct bio *bio);
 249 extern void bio_check_pages_dirty(struct bio *bio);
 250
 251 #ifndef ARCH_IMPLEMENTS_FLUSH_DCACHE_PAGE
 252 # error "You should define ARCH_IMPLEMENTS_FLUSH_DCACHE_PAGE for your platform"
 253 #endif
 254 #if ARCH_IMPLEMENTS_FLUSH_DCACHE_PAGE
 255 extern void bio_flush_dcache_pages(struct bio *bi);
 256 #else
 257 static inline void bio_flush_dcache_pages(struct bio *bi)
 258 {
 259 }
 260 #endif
 261
 262 extern struct bio *bio_copy_user(struct request_queue *, struct rq_map_data *,
 263                                  unsigned long, unsigned int, int, gfp_t);
 264 extern struct bio *bio_copy_user_iov(struct request_queue *,
 265                                      struct rq_map_data *, struct sg_iovec *,
 266                                      int, int, gfp_t);
 267 extern int bio_uncopy_user(struct bio *);
 268 void zero_fill_bio(struct bio *bio);
 269 extern struct bio_vec *bvec_alloc_bs(gfp_t, int, unsigned long *, struct bio_set *);
 270 extern void bvec_free_bs(struct bio_set *, struct bio_vec *, unsigned int);
 271 extern unsigned int bvec_nr_vecs(unsigned short idx);
 272
 273 #ifdef CONFIG_BLK_CGROUP
 274 int bio_associate_current(struct bio *bio);
 275 void bio_disassociate_task(struct bio *bio);
 276 #else   /* CONFIG_BLK_CGROUP */
 277 static inline int bio_associate_current(struct bio *bio) { return -ENOENT; }
 278 static inline void bio_disassociate_task(struct bio *bio) { }
 279 #endif  /* CONFIG_BLK_CGROUP */
 280
 281 /*
 282  * bio_set is used to allow other portions of the IO system to
 283  * allocate their own private memory pools for bio and iovec structures.
 284  * These memory pools in turn all allocate from the bio_slab
 285  * and the bvec_slabs[].
 286  */
 287 #define BIO_POOL_SIZE 2
 288 #define BIOVEC_NR_POOLS 6
 289 #define BIOVEC_MAX_IDX  (BIOVEC_NR_POOLS - 1)
 290
 291 struct bio_set {
 292         struct kmem_cache *bio_slab;
 293         unsigned int front_pad;
 294
 295         mempool_t *bio_pool;
 296 #if defined(CONFIG_BLK_DEV_INTEGRITY)
 297         mempool_t *bio_integrity_pool;
 298 #endif
 299         mempool_t *bvec_pool;
 300 };
 301
 302 struct biovec_slab {
 303         int nr_vecs;
 304         char *name;
 305         struct kmem_cache *slab;
 306 };
 307
 308 extern struct bio_set *fs_bio_set;
 309
 310 /*
 311  * a small number of entries is fine, not going to be performance critical.
 312  * basically we just need to survive
 313  */
 314 #define BIO_SPLIT_ENTRIES 2
 315
 316 #ifdef CONFIG_HIGHMEM
 317 /*
 318  * remember never ever reenable interrupts between a bvec_kmap_irq and
 319  * bvec_kunmap_irq!
 320  */
 321 static inline char *bvec_kmap_irq(struct bio_vec *bvec, unsigned long *flags)
 322 {
 323         unsigned long addr;
 324
 325         /*
 326          * might not be a highmem page, but the preempt/irq count
 327          * balancing is a lot nicer this way
 328          */
 329         local_irq_save(*flags);
 330         addr = (unsigned long) kmap_atomic(bvec->bv_page);
 331
 332         BUG_ON(addr & ~PAGE_MASK);
 333
 334         return (char *) addr + bvec->bv_offset;
 335 }
 336
 337 static inline void bvec_kunmap_irq(char *buffer, unsigned long *flags)
 338 {
 339         unsigned long ptr = (unsigned long) buffer & PAGE_MASK;
 340
 341         kunmap_atomic((void *) ptr);
 342         local_irq_restore(*flags);
 343 }
 344
 345 #else
 346 static inline char *bvec_kmap_irq(struct bio_vec *bvec, unsigned long *flags)
 347 {
 348         return page_address(bvec->bv_page) + bvec->bv_offset;
 349 }
 350
 351 static inline void bvec_kunmap_irq(char *buffer, unsigned long *flags)
 352 {
 353         *flags = 0;
 354 }
 355 #endif
 356
 357 static inline char *__bio_kmap_irq(struct bio *bio, unsigned short idx,
 358                                    unsigned long *flags)
 359 {
 360         return bvec_kmap_irq(bio_iovec_idx(bio, idx), flags);
 361 }
 362 #define __bio_kunmap_irq(buf, flags)    bvec_kunmap_irq(buf, flags)
 363
 364 #define bio_kmap_irq(bio, flags) \
 365         __bio_kmap_irq((bio), (bio)->bi_idx, (flags))
 366 #define bio_kunmap_irq(buf,flags)       __bio_kunmap_irq(buf, flags)
 367
 368 /*
 369  * Check whether this bio carries any data or not. A NULL bio is allowed.
 370  */
 371 static inline int bio_has_data(struct bio *bio)
 372 {
 373         return bio && bio->bi_io_vec != NULL;
 374 }
 375
 376 /*
 377  * BIO list management for use by remapping drivers (e.g. DM or MD) and loop.
 378  *
 379  * A bio_list anchors a singly-linked list of bios chained through the bi_next
 380  * member of the bio.  The bio_list also caches the last list member to allow
 381  * fast access to the tail.
 382  */
 383 struct bio_list {
 384         struct bio *head;
 385         struct bio *tail;
 386 };
 387
 388 static inline int bio_list_empty(const struct bio_list *bl)
 389 {
 390         return bl->head == NULL;
 391 }
 392
 393 static inline void bio_list_init(struct bio_list *bl)
 394 {
 395         bl->head = bl->tail = NULL;
 396 }
 397
 398 #define bio_list_for_each(bio, bl) \
 399         for (bio = (bl)->head; bio; bio = bio->bi_next)
 400
 401 static inline unsigned bio_list_size(const struct bio_list *bl)
 402 {
 403         unsigned sz = 0;
 404         struct bio *bio;
 405
 406         bio_list_for_each(bio, bl)
 407                 sz++;
 408
 409         return sz;
 410 }
 411
 412 static inline void bio_list_add(struct bio_list *bl, struct bio *bio)
 413 {
 414         bio->bi_next = NULL;
 415
 416         if (bl->tail)
 417                 bl->tail->bi_next = bio;
 418         else
 419                 bl->head = bio;
 420
 421         bl->tail = bio;
 422 }
 423
 424 static inline void bio_list_add_head(struct bio_list *bl, struct bio *bio)
 425 {
 426         bio->bi_next = bl->head;
 427
 428         bl->head = bio;
 429
 430         if (!bl->tail)
 431                 bl->tail = bio;
 432 }
 433
 434 static inline void bio_list_merge(struct bio_list *bl, struct bio_list *bl2)
 435 {
 436         if (!bl2->head)
 437                 return;
 438
 439         if (bl->tail)
 440                 bl->tail->bi_next = bl2->head;
 441         else
 442                 bl->head = bl2->head;
 443
 444         bl->tail = bl2->tail;
 445 }
 446
 447 static inline void bio_list_merge_head(struct bio_list *bl,
 448                                        struct bio_list *bl2)
 449 {
 450         if (!bl2->head)
 451                 return;
 452
 453         if (bl->head)
 454                 bl2->tail->bi_next = bl->head;
 455         else
 456                 bl->tail = bl2->tail;
 457
 458         bl->head = bl2->head;
 459 }
 460
 461 static inline struct bio *bio_list_peek(struct bio_list *bl)
 462 {
 463         return bl->head;
 464 }
 465
 466 static inline struct bio *bio_list_pop(struct bio_list *bl)
 467 {
 468         struct bio *bio = bl->head;
 469
 470         if (bio) {
 471                 bl->head = bl->head->bi_next;
 472                 if (!bl->head)
 473                         bl->tail = NULL;
 474
 475                 bio->bi_next = NULL;
 476         }
 477
 478         return bio;
 479 }
 480
 481 static inline struct bio *bio_list_get(struct bio_list *bl)
 482 {
 483         struct bio *bio = bl->head;
 484
 485         bl->head = bl->tail = NULL;
 486
 487         return bio;
 488 }
 489
 490 #if defined(CONFIG_BLK_DEV_INTEGRITY)
 491
 492 #define bip_vec_idx(bip, idx)   (&(bip->bip_vec[(idx)]))
 493 #define bip_vec(bip)            bip_vec_idx(bip, 0)
 494
 495 #define __bip_for_each_vec(bvl, bip, i, start_idx)                      \
 496         for (bvl = bip_vec_idx((bip), (start_idx)), i = (start_idx);    \
 497              i < (bip)->bip_vcnt;                                       \
 498              bvl++, i++)
 499
 500 #define bip_for_each_vec(bvl, bip, i)                                   \
 501         __bip_for_each_vec(bvl, bip, i, (bip)->bip_idx)
 502
 503 #define bio_for_each_integrity_vec(_bvl, _bio, _iter)                   \
 504         for_each_bio(_bio)                                              \
 505                 bip_for_each_vec(_bvl, _bio->bi_integrity, _iter)
 506
 507 #define bio_integrity(bio) (bio->bi_integrity != NULL)
 508
 509 extern struct bio_integrity_payload *bio_integrity_alloc(struct bio *, gfp_t, unsigned int);
 510 extern void bio_integrity_free(struct bio *);
 511 extern int bio_integrity_add_page(struct bio *, struct page *, unsigned int, unsigned int);
 512 extern int bio_integrity_enabled(struct bio *bio);
 513 extern int bio_integrity_set_tag(struct bio *, void *, unsigned int);
 514 extern int bio_integrity_get_tag(struct bio *, void *, unsigned int);
 515 extern int bio_integrity_prep(struct bio *);
 516 extern void bio_integrity_endio(struct bio *, int);
 517 extern void bio_integrity_advance(struct bio *, unsigned int);
 518 extern void bio_integrity_trim(struct bio *, unsigned int, unsigned int);
 519 extern void bio_integrity_split(struct bio *, struct bio_pair *, int);
 520 extern int bio_integrity_clone(struct bio *, struct bio *, gfp_t);
 521 extern int bioset_integrity_create(struct bio_set *, int);
 522 extern void bioset_integrity_free(struct bio_set *);
 523 extern void bio_integrity_init(void);
 524
 525 #else /* CONFIG_BLK_DEV_INTEGRITY */
 526
 527 static inline int bio_integrity(struct bio *bio)
 528 {
 529         return 0;
 530 }
 531
 532 static inline int bio_integrity_enabled(struct bio *bio)
 533 {
 534         return 0;
 535 }
 536
 537 static inline int bioset_integrity_create(struct bio_set *bs, int pool_size)
 538 {
 539         return 0;
 540 }
 541
 542 static inline void bioset_integrity_free (struct bio_set *bs)
 543 {
 544         return;
 545 }
 546
 547 static inline int bio_integrity_prep(struct bio *bio)
 548 {
 549         return 0;
 550 }
 551
 552 static inline void bio_integrity_free(struct bio *bio)
 553 {
 554         return;
 555 }
 556
 557 static inline int bio_integrity_clone(struct bio *bio, struct bio *bio_src,
 558                                       gfp_t gfp_mask)
 559 {
 560         return 0;
 561 }
 562
 563 static inline void bio_integrity_split(struct bio *bio, struct bio_pair *bp,
 564                                        int sectors)
 565 {
 566         return;
 567 }
 568
 569 static inline void bio_integrity_advance(struct bio *bio,
 570                                          unsigned int bytes_done)
 571 {
 572         return;
 573 }
 574
 575 static inline void bio_integrity_trim(struct bio *bio, unsigned int offset,
 576                                       unsigned int sectors)
 577 {
 578         return;
 579 }
 580
 581 static inline void bio_integrity_init(void)
 582 {
 583         return;
 584 }
 585
 586 #endif /* CONFIG_BLK_DEV_INTEGRITY */
 587
 588 #endif /* CONFIG_BLOCK */
 589 #endif /* __LINUX_BIO_H */