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
 230 extern int bio_add_page(struct bio *, struct page *, unsigned int,unsigned int);
 231 extern int bio_add_pc_page(struct request_queue *, struct bio *, struct page *,
 232                            unsigned int, unsigned int);
 233 extern int bio_get_nr_vecs(struct block_device *);
 234 extern sector_t bio_sector_offset(struct bio *, unsigned short, unsigned int);
 235 extern struct bio *bio_map_user(struct request_queue *, struct block_device *,
 236                                 unsigned long, unsigned int, int, gfp_t);
 237 struct sg_iovec;
 238 struct rq_map_data;
 239 extern struct bio *bio_map_user_iov(struct request_queue *,
 240                                     struct block_device *,
 241                                     struct sg_iovec *, int, int, gfp_t);
 242 extern void bio_unmap_user(struct bio *);
 243 extern struct bio *bio_map_kern(struct request_queue *, void *, unsigned int,
 244                                 gfp_t);
 245 extern struct bio *bio_copy_kern(struct request_queue *, void *, unsigned int,
 246                                  gfp_t, int);
 247 extern void bio_set_pages_dirty(struct bio *bio);
 248 extern void bio_check_pages_dirty(struct bio *bio);
 249
 250 #ifndef ARCH_IMPLEMENTS_FLUSH_DCACHE_PAGE
 251 # error "You should define ARCH_IMPLEMENTS_FLUSH_DCACHE_PAGE for your platform"
 252 #endif
 253 #if ARCH_IMPLEMENTS_FLUSH_DCACHE_PAGE
 254 extern void bio_flush_dcache_pages(struct bio *bi);
 255 #else
 256 static inline void bio_flush_dcache_pages(struct bio *bi)
 257 {
 258 }
 259 #endif
 260
 261 extern struct bio *bio_copy_user(struct request_queue *, struct rq_map_data *,
 262                                  unsigned long, unsigned int, int, gfp_t);
 263 extern struct bio *bio_copy_user_iov(struct request_queue *,
 264                                      struct rq_map_data *, struct sg_iovec *,
 265                                      int, int, gfp_t);
 266 extern int bio_uncopy_user(struct bio *);
 267 void zero_fill_bio(struct bio *bio);
 268 extern struct bio_vec *bvec_alloc_bs(gfp_t, int, unsigned long *, struct bio_set *);
 269 extern void bvec_free_bs(struct bio_set *, struct bio_vec *, unsigned int);
 270 extern unsigned int bvec_nr_vecs(unsigned short idx);
 271
 272 /*
 273  * bio_set is used to allow other portions of the IO system to
 274  * allocate their own private memory pools for bio and iovec structures.
 275  * These memory pools in turn all allocate from the bio_slab
 276  * and the bvec_slabs[].
 277  */
 278 #define BIO_POOL_SIZE 2
 279 #define BIOVEC_NR_POOLS 6
 280 #define BIOVEC_MAX_IDX  (BIOVEC_NR_POOLS - 1)
 281
 282 struct bio_set {
 283         struct kmem_cache *bio_slab;
 284         unsigned int front_pad;
 285
 286         mempool_t *bio_pool;
 287 #if defined(CONFIG_BLK_DEV_INTEGRITY)
 288         mempool_t *bio_integrity_pool;
 289 #endif
 290         mempool_t *bvec_pool;
 291 };
 292
 293 struct biovec_slab {
 294         int nr_vecs;
 295         char *name;
 296         struct kmem_cache *slab;
 297 };
 298
 299 extern struct bio_set *fs_bio_set;
 300
 301 /*
 302  * a small number of entries is fine, not going to be performance critical.
 303  * basically we just need to survive
 304  */
 305 #define BIO_SPLIT_ENTRIES 2
 306
 307 #ifdef CONFIG_HIGHMEM
 308 /*
 309  * remember never ever reenable interrupts between a bvec_kmap_irq and
 310  * bvec_kunmap_irq!
 311  */
 312 static inline char *bvec_kmap_irq(struct bio_vec *bvec, unsigned long *flags)
 313 {
 314         unsigned long addr;
 315
 316         /*
 317          * might not be a highmem page, but the preempt/irq count
 318          * balancing is a lot nicer this way
 319          */
 320         local_irq_save(*flags);
 321         addr = (unsigned long) kmap_atomic(bvec->bv_page);
 322
 323         BUG_ON(addr & ~PAGE_MASK);
 324
 325         return (char *) addr + bvec->bv_offset;
 326 }
 327
 328 static inline void bvec_kunmap_irq(char *buffer, unsigned long *flags)
 329 {
 330         unsigned long ptr = (unsigned long) buffer & PAGE_MASK;
 331
 332         kunmap_atomic((void *) ptr);
 333         local_irq_restore(*flags);
 334 }
 335
 336 #else
 337 static inline char *bvec_kmap_irq(struct bio_vec *bvec, unsigned long *flags)
 338 {
 339         return page_address(bvec->bv_page) + bvec->bv_offset;
 340 }
 341
 342 static inline void bvec_kunmap_irq(char *buffer, unsigned long *flags)
 343 {
 344         *flags = 0;
 345 }
 346 #endif
 347
 348 static inline char *__bio_kmap_irq(struct bio *bio, unsigned short idx,
 349                                    unsigned long *flags)
 350 {
 351         return bvec_kmap_irq(bio_iovec_idx(bio, idx), flags);
 352 }
 353 #define __bio_kunmap_irq(buf, flags)    bvec_kunmap_irq(buf, flags)
 354
 355 #define bio_kmap_irq(bio, flags) \
 356         __bio_kmap_irq((bio), (bio)->bi_idx, (flags))
 357 #define bio_kunmap_irq(buf,flags)       __bio_kunmap_irq(buf, flags)
 358
 359 /*
 360  * Check whether this bio carries any data or not. A NULL bio is allowed.
 361  */
 362 static inline int bio_has_data(struct bio *bio)
 363 {
 364         return bio && bio->bi_io_vec != NULL;
 365 }
 366
 367 /*
 368  * BIO list management for use by remapping drivers (e.g. DM or MD) and loop.
 369  *
 370  * A bio_list anchors a singly-linked list of bios chained through the bi_next
 371  * member of the bio.  The bio_list also caches the last list member to allow
 372  * fast access to the tail.
 373  */
 374 struct bio_list {
 375         struct bio *head;
 376         struct bio *tail;
 377 };
 378
 379 static inline int bio_list_empty(const struct bio_list *bl)
 380 {
 381         return bl->head == NULL;
 382 }
 383
 384 static inline void bio_list_init(struct bio_list *bl)
 385 {
 386         bl->head = bl->tail = NULL;
 387 }
 388
 389 #define bio_list_for_each(bio, bl) \
 390         for (bio = (bl)->head; bio; bio = bio->bi_next)
 391
 392 static inline unsigned bio_list_size(const struct bio_list *bl)
 393 {
 394         unsigned sz = 0;
 395         struct bio *bio;
 396
 397         bio_list_for_each(bio, bl)
 398                 sz++;
 399
 400         return sz;
 401 }
 402
 403 static inline void bio_list_add(struct bio_list *bl, struct bio *bio)
 404 {
 405         bio->bi_next = NULL;
 406
 407         if (bl->tail)
 408                 bl->tail->bi_next = bio;
 409         else
 410                 bl->head = bio;
 411
 412         bl->tail = bio;
 413 }
 414
 415 static inline void bio_list_add_head(struct bio_list *bl, struct bio *bio)
 416 {
 417         bio->bi_next = bl->head;
 418
 419         bl->head = bio;
 420
 421         if (!bl->tail)
 422                 bl->tail = bio;
 423 }
 424
 425 static inline void bio_list_merge(struct bio_list *bl, struct bio_list *bl2)
 426 {
 427         if (!bl2->head)
 428                 return;
 429
 430         if (bl->tail)
 431                 bl->tail->bi_next = bl2->head;
 432         else
 433                 bl->head = bl2->head;
 434
 435         bl->tail = bl2->tail;
 436 }
 437
 438 static inline void bio_list_merge_head(struct bio_list *bl,
 439                                        struct bio_list *bl2)
 440 {
 441         if (!bl2->head)
 442                 return;
 443
 444         if (bl->head)
 445                 bl2->tail->bi_next = bl->head;
 446         else
 447                 bl->tail = bl2->tail;
 448
 449         bl->head = bl2->head;
 450 }
 451
 452 static inline struct bio *bio_list_peek(struct bio_list *bl)
 453 {
 454         return bl->head;
 455 }
 456
 457 static inline struct bio *bio_list_pop(struct bio_list *bl)
 458 {
 459         struct bio *bio = bl->head;
 460
 461         if (bio) {
 462                 bl->head = bl->head->bi_next;
 463                 if (!bl->head)
 464                         bl->tail = NULL;
 465
 466                 bio->bi_next = NULL;
 467         }
 468
 469         return bio;
 470 }
 471
 472 static inline struct bio *bio_list_get(struct bio_list *bl)
 473 {
 474         struct bio *bio = bl->head;
 475
 476         bl->head = bl->tail = NULL;
 477
 478         return bio;
 479 }
 480
 481 #if defined(CONFIG_BLK_DEV_INTEGRITY)
 482
 483 #define bip_vec_idx(bip, idx)   (&(bip->bip_vec[(idx)]))
 484 #define bip_vec(bip)            bip_vec_idx(bip, 0)
 485
 486 #define __bip_for_each_vec(bvl, bip, i, start_idx)                      \
 487         for (bvl = bip_vec_idx((bip), (start_idx)), i = (start_idx);    \
 488              i < (bip)->bip_vcnt;                                       \
 489              bvl++, i++)
 490
 491 #define bip_for_each_vec(bvl, bip, i)                                   \
 492         __bip_for_each_vec(bvl, bip, i, (bip)->bip_idx)
 493
 494 #define bio_for_each_integrity_vec(_bvl, _bio, _iter)                   \
 495         for_each_bio(_bio)                                              \
 496                 bip_for_each_vec(_bvl, _bio->bi_integrity, _iter)
 497
 498 #define bio_integrity(bio) (bio->bi_integrity != NULL)
 499
 500 extern struct bio_integrity_payload *bio_integrity_alloc_bioset(struct bio *, gfp_t, unsigned int, struct bio_set *);
 501 extern struct bio_integrity_payload *bio_integrity_alloc(struct bio *, gfp_t, unsigned int);
 502 extern void bio_integrity_free(struct bio *, struct bio_set *);
 503 extern int bio_integrity_add_page(struct bio *, struct page *, unsigned int, unsigned int);
 504 extern int bio_integrity_enabled(struct bio *bio);
 505 extern int bio_integrity_set_tag(struct bio *, void *, unsigned int);
 506 extern int bio_integrity_get_tag(struct bio *, void *, unsigned int);
 507 extern int bio_integrity_prep(struct bio *);
 508 extern void bio_integrity_endio(struct bio *, int);
 509 extern void bio_integrity_advance(struct bio *, unsigned int);
 510 extern void bio_integrity_trim(struct bio *, unsigned int, unsigned int);
 511 extern void bio_integrity_split(struct bio *, struct bio_pair *, int);
 512 extern int bio_integrity_clone(struct bio *, struct bio *, gfp_t, struct bio_set *);
 513 extern int bioset_integrity_create(struct bio_set *, int);
 514 extern void bioset_integrity_free(struct bio_set *);
 515 extern void bio_integrity_init(void);
 516
 517 #else /* CONFIG_BLK_DEV_INTEGRITY */
 518
 519 static inline int bio_integrity(struct bio *bio)
 520 {
 521         return 0;
 522 }
 523
 524 static inline int bio_integrity_enabled(struct bio *bio)
 525 {
 526         return 0;
 527 }
 528
 529 static inline int bioset_integrity_create(struct bio_set *bs, int pool_size)
 530 {
 531         return 0;
 532 }
 533
 534 static inline void bioset_integrity_free (struct bio_set *bs)
 535 {
 536         return;
 537 }
 538
 539 static inline int bio_integrity_prep(struct bio *bio)
 540 {
 541         return 0;
 542 }
 543
 544 static inline void bio_integrity_free(struct bio *bio, struct bio_set *bs)
 545 {
 546         return;
 547 }
 548
 549 static inline int bio_integrity_clone(struct bio *bio, struct bio *bio_src,
 550                                       gfp_t gfp_mask, struct bio_set *bs)
 551 {
 552         return 0;
 553 }
 554
 555 static inline void bio_integrity_split(struct bio *bio, struct bio_pair *bp,
 556                                        int sectors)
 557 {
 558         return;
 559 }
 560
 561 static inline void bio_integrity_advance(struct bio *bio,
 562                                          unsigned int bytes_done)
 563 {
 564         return;
 565 }
 566
 567 static inline void bio_integrity_trim(struct bio *bio, unsigned int offset,
 568                                       unsigned int sectors)
 569 {
 570         return;
 571 }
 572
 573 static inline void bio_integrity_init(void)
 574 {
 575         return;
 576 }
 577
 578 #endif /* CONFIG_BLK_DEV_INTEGRITY */
 579
 580 #endif /* CONFIG_BLOCK */
 581 #endif /* __LINUX_BIO_H */