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_bioset(gfp_t, int, struct bio_set *);
 216 extern void bio_put(struct bio *);
 217
 218 extern void __bio_clone(struct bio *, struct bio *);
 219 extern struct bio *bio_clone_bioset(struct bio *, gfp_t, struct bio_set *bs);
 220
 221 extern struct bio_set *fs_bio_set;
 222
 223 static inline struct bio *bio_alloc(gfp_t gfp_mask, unsigned int nr_iovecs)
 224 {
 225         return bio_alloc_bioset(gfp_mask, nr_iovecs, fs_bio_set);
 226 }
 227
 228 static inline struct bio *bio_clone(struct bio *bio, gfp_t gfp_mask)
 229 {
 230         return bio_clone_bioset(bio, gfp_mask, fs_bio_set);
 231 }
 232
 233 static inline struct bio *bio_kmalloc(gfp_t gfp_mask, unsigned int nr_iovecs)
 234 {
 235         return bio_alloc_bioset(gfp_mask, nr_iovecs, NULL);
 236 }
 237
 238 static inline struct bio *bio_clone_kmalloc(struct bio *bio, gfp_t gfp_mask)
 239 {
 240         return bio_clone_bioset(bio, gfp_mask, NULL);
 241
 242 }
 243
 244 extern void bio_endio(struct bio *, int);
 245 struct request_queue;
 246 extern int bio_phys_segments(struct request_queue *, struct bio *);
 247
 248 extern void bio_init(struct bio *);
 249 extern void bio_reset(struct bio *);
 250
 251 extern int bio_add_page(struct bio *, struct page *, unsigned int,unsigned int);
 252 extern int bio_add_pc_page(struct request_queue *, struct bio *, struct page *,
 253                            unsigned int, unsigned int);
 254 extern int bio_get_nr_vecs(struct block_device *);
 255 extern sector_t bio_sector_offset(struct bio *, unsigned short, unsigned int);
 256 extern struct bio *bio_map_user(struct request_queue *, struct block_device *,
 257                                 unsigned long, unsigned int, int, gfp_t);
 258 struct sg_iovec;
 259 struct rq_map_data;
 260 extern struct bio *bio_map_user_iov(struct request_queue *,
 261                                     struct block_device *,
 262                                     struct sg_iovec *, int, int, gfp_t);
 263 extern void bio_unmap_user(struct bio *);
 264 extern struct bio *bio_map_kern(struct request_queue *, void *, unsigned int,
 265                                 gfp_t);
 266 extern struct bio *bio_copy_kern(struct request_queue *, void *, unsigned int,
 267                                  gfp_t, int);
 268 extern void bio_set_pages_dirty(struct bio *bio);
 269 extern void bio_check_pages_dirty(struct bio *bio);
 270
 271 #ifndef ARCH_IMPLEMENTS_FLUSH_DCACHE_PAGE
 272 # error "You should define ARCH_IMPLEMENTS_FLUSH_DCACHE_PAGE for your platform"
 273 #endif
 274 #if ARCH_IMPLEMENTS_FLUSH_DCACHE_PAGE
 275 extern void bio_flush_dcache_pages(struct bio *bi);
 276 #else
 277 static inline void bio_flush_dcache_pages(struct bio *bi)
 278 {
 279 }
 280 #endif
 281
 282 extern struct bio *bio_copy_user(struct request_queue *, struct rq_map_data *,
 283                                  unsigned long, unsigned int, int, gfp_t);
 284 extern struct bio *bio_copy_user_iov(struct request_queue *,
 285                                      struct rq_map_data *, struct sg_iovec *,
 286                                      int, int, gfp_t);
 287 extern int bio_uncopy_user(struct bio *);
 288 void zero_fill_bio(struct bio *bio);
 289 extern struct bio_vec *bvec_alloc_bs(gfp_t, int, unsigned long *, struct bio_set *);
 290 extern void bvec_free_bs(struct bio_set *, struct bio_vec *, unsigned int);
 291 extern unsigned int bvec_nr_vecs(unsigned short idx);
 292
 293 #ifdef CONFIG_BLK_CGROUP
 294 int bio_associate_current(struct bio *bio);
 295 void bio_disassociate_task(struct bio *bio);
 296 #else   /* CONFIG_BLK_CGROUP */
 297 static inline int bio_associate_current(struct bio *bio) { return -ENOENT; }
 298 static inline void bio_disassociate_task(struct bio *bio) { }
 299 #endif  /* CONFIG_BLK_CGROUP */
 300
 301 /*
 302  * bio_set is used to allow other portions of the IO system to
 303  * allocate their own private memory pools for bio and iovec structures.
 304  * These memory pools in turn all allocate from the bio_slab
 305  * and the bvec_slabs[].
 306  */
 307 #define BIO_POOL_SIZE 2
 308 #define BIOVEC_NR_POOLS 6
 309 #define BIOVEC_MAX_IDX  (BIOVEC_NR_POOLS - 1)
 310
 311 struct bio_set {
 312         struct kmem_cache *bio_slab;
 313         unsigned int front_pad;
 314
 315         mempool_t *bio_pool;
 316 #if defined(CONFIG_BLK_DEV_INTEGRITY)
 317         mempool_t *bio_integrity_pool;
 318 #endif
 319         mempool_t *bvec_pool;
 320 };
 321
 322 struct biovec_slab {
 323         int nr_vecs;
 324         char *name;
 325         struct kmem_cache *slab;
 326 };
 327
 328 /*
 329  * a small number of entries is fine, not going to be performance critical.
 330  * basically we just need to survive
 331  */
 332 #define BIO_SPLIT_ENTRIES 2
 333
 334 #ifdef CONFIG_HIGHMEM
 335 /*
 336  * remember never ever reenable interrupts between a bvec_kmap_irq and
 337  * bvec_kunmap_irq!
 338  */
 339 static inline char *bvec_kmap_irq(struct bio_vec *bvec, unsigned long *flags)
 340 {
 341         unsigned long addr;
 342
 343         /*
 344          * might not be a highmem page, but the preempt/irq count
 345          * balancing is a lot nicer this way
 346          */
 347         local_irq_save(*flags);
 348         addr = (unsigned long) kmap_atomic(bvec->bv_page);
 349
 350         BUG_ON(addr & ~PAGE_MASK);
 351
 352         return (char *) addr + bvec->bv_offset;
 353 }
 354
 355 static inline void bvec_kunmap_irq(char *buffer, unsigned long *flags)
 356 {
 357         unsigned long ptr = (unsigned long) buffer & PAGE_MASK;
 358
 359         kunmap_atomic((void *) ptr);
 360         local_irq_restore(*flags);
 361 }
 362
 363 #else
 364 static inline char *bvec_kmap_irq(struct bio_vec *bvec, unsigned long *flags)
 365 {
 366         return page_address(bvec->bv_page) + bvec->bv_offset;
 367 }
 368
 369 static inline void bvec_kunmap_irq(char *buffer, unsigned long *flags)
 370 {
 371         *flags = 0;
 372 }
 373 #endif
 374
 375 static inline char *__bio_kmap_irq(struct bio *bio, unsigned short idx,
 376                                    unsigned long *flags)
 377 {
 378         return bvec_kmap_irq(bio_iovec_idx(bio, idx), flags);
 379 }
 380 #define __bio_kunmap_irq(buf, flags)    bvec_kunmap_irq(buf, flags)
 381
 382 #define bio_kmap_irq(bio, flags) \
 383         __bio_kmap_irq((bio), (bio)->bi_idx, (flags))
 384 #define bio_kunmap_irq(buf,flags)       __bio_kunmap_irq(buf, flags)
 385
 386 /*
 387  * Check whether this bio carries any data or not. A NULL bio is allowed.
 388  */
 389 static inline int bio_has_data(struct bio *bio)
 390 {
 391         return bio && bio->bi_io_vec != NULL;
 392 }
 393
 394 /*
 395  * BIO list management for use by remapping drivers (e.g. DM or MD) and loop.
 396  *
 397  * A bio_list anchors a singly-linked list of bios chained through the bi_next
 398  * member of the bio.  The bio_list also caches the last list member to allow
 399  * fast access to the tail.
 400  */
 401 struct bio_list {
 402         struct bio *head;
 403         struct bio *tail;
 404 };
 405
 406 static inline int bio_list_empty(const struct bio_list *bl)
 407 {
 408         return bl->head == NULL;
 409 }
 410
 411 static inline void bio_list_init(struct bio_list *bl)
 412 {
 413         bl->head = bl->tail = NULL;
 414 }
 415
 416 #define bio_list_for_each(bio, bl) \
 417         for (bio = (bl)->head; bio; bio = bio->bi_next)
 418
 419 static inline unsigned bio_list_size(const struct bio_list *bl)
 420 {
 421         unsigned sz = 0;
 422         struct bio *bio;
 423
 424         bio_list_for_each(bio, bl)
 425                 sz++;
 426
 427         return sz;
 428 }
 429
 430 static inline void bio_list_add(struct bio_list *bl, struct bio *bio)
 431 {
 432         bio->bi_next = NULL;
 433
 434         if (bl->tail)
 435                 bl->tail->bi_next = bio;
 436         else
 437                 bl->head = bio;
 438
 439         bl->tail = bio;
 440 }
 441
 442 static inline void bio_list_add_head(struct bio_list *bl, struct bio *bio)
 443 {
 444         bio->bi_next = bl->head;
 445
 446         bl->head = bio;
 447
 448         if (!bl->tail)
 449                 bl->tail = bio;
 450 }
 451
 452 static inline void bio_list_merge(struct bio_list *bl, struct bio_list *bl2)
 453 {
 454         if (!bl2->head)
 455                 return;
 456
 457         if (bl->tail)
 458                 bl->tail->bi_next = bl2->head;
 459         else
 460                 bl->head = bl2->head;
 461
 462         bl->tail = bl2->tail;
 463 }
 464
 465 static inline void bio_list_merge_head(struct bio_list *bl,
 466                                        struct bio_list *bl2)
 467 {
 468         if (!bl2->head)
 469                 return;
 470
 471         if (bl->head)
 472                 bl2->tail->bi_next = bl->head;
 473         else
 474                 bl->tail = bl2->tail;
 475
 476         bl->head = bl2->head;
 477 }
 478
 479 static inline struct bio *bio_list_peek(struct bio_list *bl)
 480 {
 481         return bl->head;
 482 }
 483
 484 static inline struct bio *bio_list_pop(struct bio_list *bl)
 485 {
 486         struct bio *bio = bl->head;
 487
 488         if (bio) {
 489                 bl->head = bl->head->bi_next;
 490                 if (!bl->head)
 491                         bl->tail = NULL;
 492
 493                 bio->bi_next = NULL;
 494         }
 495
 496         return bio;
 497 }
 498
 499 static inline struct bio *bio_list_get(struct bio_list *bl)
 500 {
 501         struct bio *bio = bl->head;
 502
 503         bl->head = bl->tail = NULL;
 504
 505         return bio;
 506 }
 507
 508 #if defined(CONFIG_BLK_DEV_INTEGRITY)
 509
 510 #define bip_vec_idx(bip, idx)   (&(bip->bip_vec[(idx)]))
 511 #define bip_vec(bip)            bip_vec_idx(bip, 0)
 512
 513 #define __bip_for_each_vec(bvl, bip, i, start_idx)                      \
 514         for (bvl = bip_vec_idx((bip), (start_idx)), i = (start_idx);    \
 515              i < (bip)->bip_vcnt;                                       \
 516              bvl++, i++)
 517
 518 #define bip_for_each_vec(bvl, bip, i)                                   \
 519         __bip_for_each_vec(bvl, bip, i, (bip)->bip_idx)
 520
 521 #define bio_for_each_integrity_vec(_bvl, _bio, _iter)                   \
 522         for_each_bio(_bio)                                              \
 523                 bip_for_each_vec(_bvl, _bio->bi_integrity, _iter)
 524
 525 #define bio_integrity(bio) (bio->bi_integrity != NULL)
 526
 527 extern struct bio_integrity_payload *bio_integrity_alloc(struct bio *, gfp_t, unsigned int);
 528 extern void bio_integrity_free(struct bio *);
 529 extern int bio_integrity_add_page(struct bio *, struct page *, unsigned int, unsigned int);
 530 extern int bio_integrity_enabled(struct bio *bio);
 531 extern int bio_integrity_set_tag(struct bio *, void *, unsigned int);
 532 extern int bio_integrity_get_tag(struct bio *, void *, unsigned int);
 533 extern int bio_integrity_prep(struct bio *);
 534 extern void bio_integrity_endio(struct bio *, int);
 535 extern void bio_integrity_advance(struct bio *, unsigned int);
 536 extern void bio_integrity_trim(struct bio *, unsigned int, unsigned int);
 537 extern void bio_integrity_split(struct bio *, struct bio_pair *, int);
 538 extern int bio_integrity_clone(struct bio *, struct bio *, gfp_t);
 539 extern int bioset_integrity_create(struct bio_set *, int);
 540 extern void bioset_integrity_free(struct bio_set *);
 541 extern void bio_integrity_init(void);
 542
 543 #else /* CONFIG_BLK_DEV_INTEGRITY */
 544
 545 static inline int bio_integrity(struct bio *bio)
 546 {
 547         return 0;
 548 }
 549
 550 static inline int bio_integrity_enabled(struct bio *bio)
 551 {
 552         return 0;
 553 }
 554
 555 static inline int bioset_integrity_create(struct bio_set *bs, int pool_size)
 556 {
 557         return 0;
 558 }
 559
 560 static inline void bioset_integrity_free (struct bio_set *bs)
 561 {
 562         return;
 563 }
 564
 565 static inline int bio_integrity_prep(struct bio *bio)
 566 {
 567         return 0;
 568 }
 569
 570 static inline void bio_integrity_free(struct bio *bio)
 571 {
 572         return;
 573 }
 574
 575 static inline int bio_integrity_clone(struct bio *bio, struct bio *bio_src,
 576                                       gfp_t gfp_mask)
 577 {
 578         return 0;
 579 }
 580
 581 static inline void bio_integrity_split(struct bio *bio, struct bio_pair *bp,
 582                                        int sectors)
 583 {
 584         return;
 585 }
 586
 587 static inline void bio_integrity_advance(struct bio *bio,
 588                                          unsigned int bytes_done)
 589 {
 590         return;
 591 }
 592
 593 static inline void bio_integrity_trim(struct bio *bio, unsigned int offset,
 594                                       unsigned int sectors)
 595 {
 596         return;
 597 }
 598
 599 static inline void bio_integrity_init(void)
 600 {
 601         return;
 602 }
 603
 604 #endif /* CONFIG_BLK_DEV_INTEGRITY */
 605
 606 #endif /* CONFIG_BLOCK */
 607 #endif /* __LINUX_BIO_H */