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
  27 #ifdef CONFIG_BLOCK
  28
  29 #include <asm/io.h>
  30
  31 /* struct bio, bio_vec and BIO_* flags are defined in blk_types.h */
  32 #include <linux/blk_types.h>
  33
  34 #define BIO_DEBUG
  35
  36 #ifdef BIO_DEBUG
  37 #define BIO_BUG_ON      BUG_ON
  38 #else
  39 #define BIO_BUG_ON
  40 #endif
  41
  42 #define BIO_MAX_PAGES           256
  43 #define BIO_MAX_SIZE            (BIO_MAX_PAGES << PAGE_CACHE_SHIFT)
  44 #define BIO_MAX_SECTORS         (BIO_MAX_SIZE >> 9)
  45
  46 /*
  47  * upper 16 bits of bi_rw define the io priority of this bio
  48  */
  49 #define BIO_PRIO_SHIFT  (8 * sizeof(unsigned long) - IOPRIO_BITS)
  50 #define bio_prio(bio)   ((bio)->bi_rw >> BIO_PRIO_SHIFT)
  51 #define bio_prio_valid(bio)     ioprio_valid(bio_prio(bio))
  52
  53 #define bio_set_prio(bio, prio)         do {                    \
  54         WARN_ON(prio >= (1 << IOPRIO_BITS));                    \
  55         (bio)->bi_rw &= ((1UL << BIO_PRIO_SHIFT) - 1);          \
  56         (bio)->bi_rw |= ((unsigned long) (prio) << BIO_PRIO_SHIFT);     \
  57 } while (0)
  58
  59 /*
  60  * various member access, note that bio_data should of course not be used
  61  * on highmem page vectors
  62  */
  63 #define bio_iovec_idx(bio, idx) (&((bio)->bi_io_vec[(idx)]))
  64 #define bio_iovec(bio)          bio_iovec_idx((bio), (bio)->bi_idx)
  65 #define bio_page(bio)           bio_iovec((bio))->bv_page
  66 #define bio_offset(bio)         bio_iovec((bio))->bv_offset
  67 #define bio_segments(bio)       ((bio)->bi_vcnt - (bio)->bi_idx)
  68 #define bio_sectors(bio)        ((bio)->bi_size >> 9)
  69
  70 static inline unsigned int bio_cur_bytes(struct bio *bio)
  71 {
  72         if (bio->bi_vcnt)
  73                 return bio_iovec(bio)->bv_len;
  74         else /* dataless requests such as discard */
  75                 return bio->bi_size;
  76 }
  77
  78 static inline void *bio_data(struct bio *bio)
  79 {
  80         if (bio->bi_vcnt)
  81                 return page_address(bio_page(bio)) + bio_offset(bio);
  82
  83         return NULL;
  84 }
  85
  86 static inline int bio_has_allocated_vec(struct bio *bio)
  87 {
  88         return bio->bi_io_vec && bio->bi_io_vec != bio->bi_inline_vecs;
  89 }
  90
  91 /*
  92  * will die
  93  */
  94 #define bio_to_phys(bio)        (page_to_phys(bio_page((bio))) + (unsigned long) bio_offset((bio)))
  95 #define bvec_to_phys(bv)        (page_to_phys((bv)->bv_page) + (unsigned long) (bv)->bv_offset)
  96
  97 /*
  98  * queues that have highmem support enabled may still need to revert to
  99  * PIO transfers occasionally and thus map high pages temporarily. For
 100  * permanent PIO fall back, user is probably better off disabling highmem
 101  * I/O completely on that queue (see ide-dma for example)
 102  */
 103 #define __bio_kmap_atomic(bio, idx, kmtype)                             \
 104         (kmap_atomic(bio_iovec_idx((bio), (idx))->bv_page, kmtype) +    \
 105                 bio_iovec_idx((bio), (idx))->bv_offset)
 106
 107 #define __bio_kunmap_atomic(addr, kmtype) kunmap_atomic(addr, kmtype)
 108
 109 /*
 110  * merge helpers etc
 111  */
 112
 113 #define __BVEC_END(bio)         bio_iovec_idx((bio), (bio)->bi_vcnt - 1)
 114 #define __BVEC_START(bio)       bio_iovec_idx((bio), (bio)->bi_idx)
 115
 116 /* Default implementation of BIOVEC_PHYS_MERGEABLE */
 117 #define __BIOVEC_PHYS_MERGEABLE(vec1, vec2)     \
 118         ((bvec_to_phys((vec1)) + (vec1)->bv_len) == bvec_to_phys((vec2)))
 119
 120 /*
 121  * allow arch override, for eg virtualized architectures (put in asm/io.h)
 122  */
 123 #ifndef BIOVEC_PHYS_MERGEABLE
 124 #define BIOVEC_PHYS_MERGEABLE(vec1, vec2)       \
 125         __BIOVEC_PHYS_MERGEABLE(vec1, vec2)
 126 #endif
 127
 128 #define __BIO_SEG_BOUNDARY(addr1, addr2, mask) \
 129         (((addr1) | (mask)) == (((addr2) - 1) | (mask)))
 130 #define BIOVEC_SEG_BOUNDARY(q, b1, b2) \
 131         __BIO_SEG_BOUNDARY(bvec_to_phys((b1)), bvec_to_phys((b2)) + (b2)->bv_len, queue_segment_boundary((q)))
 132 #define BIO_SEG_BOUNDARY(q, b1, b2) \
 133         BIOVEC_SEG_BOUNDARY((q), __BVEC_END((b1)), __BVEC_START((b2)))
 134
 135 #define bio_io_error(bio) bio_endio((bio), -EIO)
 136
 137 /*
 138  * drivers should not use the __ version unless they _really_ want to
 139  * run through the entire bio and not just pending pieces
 140  */
 141 #define __bio_for_each_segment(bvl, bio, i, start_idx)                  \
 142         for (bvl = bio_iovec_idx((bio), (start_idx)), i = (start_idx);  \
 143              i < (bio)->bi_vcnt;                                        \
 144              bvl++, i++)
 145
 146 #define bio_for_each_segment(bvl, bio, i)                               \
 147         __bio_for_each_segment(bvl, bio, i, (bio)->bi_idx)
 148
 149 /*
 150  * get a reference to a bio, so it won't disappear. the intended use is
 151  * something like:
 152  *
 153  * bio_get(bio);
 154  * submit_bio(rw, bio);
 155  * if (bio->bi_flags ...)
 156  *      do_something
 157  * bio_put(bio);
 158  *
 159  * without the bio_get(), it could potentially complete I/O before submit_bio
 160  * returns. and then bio would be freed memory when if (bio->bi_flags ...)
 161  * runs
 162  */
 163 #define bio_get(bio)    atomic_inc(&(bio)->bi_cnt)
 164
 165 #if defined(CONFIG_BLK_DEV_INTEGRITY)
 166 /*
 167  * bio integrity payload
 168  */
 169 struct bio_integrity_payload {
 170         struct bio              *bip_bio;       /* parent bio */
 171
 172         sector_t                bip_sector;     /* virtual start sector */
 173
 174         void                    *bip_buf;       /* generated integrity data */
 175         bio_end_io_t            *bip_end_io;    /* saved I/O completion fn */
 176
 177         unsigned int            bip_size;
 178
 179         unsigned short          bip_slab;       /* slab the bip came from */
 180         unsigned short          bip_vcnt;       /* # of integrity bio_vecs */
 181         unsigned short          bip_idx;        /* current bip_vec index */
 182
 183         struct work_struct      bip_work;       /* I/O completion */
 184         struct bio_vec          bip_vec[0];     /* embedded bvec array */
 185 };
 186 #endif /* CONFIG_BLK_DEV_INTEGRITY */
 187
 188 /*
 189  * A bio_pair is used when we need to split a bio.
 190  * This can only happen for a bio that refers to just one
 191  * page of data, and in the unusual situation when the
 192  * page crosses a chunk/device boundary
 193  *
 194  * The address of the master bio is stored in bio1.bi_private
 195  * The address of the pool the pair was allocated from is stored
 196  *   in bio2.bi_private
 197  */
 198 struct bio_pair {
 199         struct bio                      bio1, bio2;
 200         struct bio_vec                  bv1, bv2;
 201 #if defined(CONFIG_BLK_DEV_INTEGRITY)
 202         struct bio_integrity_payload    bip1, bip2;
 203         struct bio_vec                  iv1, iv2;
 204 #endif
 205         atomic_t                        cnt;
 206         int                             error;
 207 };
 208 extern struct bio_pair *bio_split(struct bio *bi, int first_sectors);
 209 extern void bio_pair_release(struct bio_pair *dbio);
 210
 211 extern struct bio_set *bioset_create(unsigned int, unsigned int);
 212 extern void bioset_free(struct bio_set *);
 213
 214 extern struct bio *bio_alloc(gfp_t, int);
 215 extern struct bio *bio_kmalloc(gfp_t, int);
 216 extern struct bio *bio_alloc_bioset(gfp_t, int, struct bio_set *);
 217 extern void bio_put(struct bio *);
 218 extern void bio_free(struct bio *, struct bio_set *);
 219
 220 extern void bio_endio(struct bio *, int);
 221 struct request_queue;
 222 extern int bio_phys_segments(struct request_queue *, struct bio *);
 223
 224 extern void __bio_clone(struct bio *, struct bio *);
 225 extern struct bio *bio_clone(struct bio *, gfp_t);
 226
 227 extern void bio_init(struct bio *);
 228
 229 extern int bio_add_page(struct bio *, struct page *, unsigned int,unsigned int);
 230 extern int bio_add_pc_page(struct request_queue *, struct bio *, struct page *,
 231                            unsigned int, unsigned int);
 232 extern int bio_get_nr_vecs(struct block_device *);
 233 extern sector_t bio_sector_offset(struct bio *, unsigned short, unsigned int);
 234 extern struct bio *bio_map_user(struct request_queue *, struct block_device *,
 235                                 unsigned long, unsigned int, int, gfp_t);
 236 struct sg_iovec;
 237 struct rq_map_data;
 238 extern struct bio *bio_map_user_iov(struct request_queue *,
 239                                     struct block_device *,
 240                                     struct sg_iovec *, int, int, gfp_t);
 241 extern void bio_unmap_user(struct bio *);
 242 extern struct bio *bio_map_kern(struct request_queue *, void *, unsigned int,
 243                                 gfp_t);
 244 extern struct bio *bio_copy_kern(struct request_queue *, void *, unsigned int,
 245                                  gfp_t, int);
 246 extern void bio_set_pages_dirty(struct bio *bio);
 247 extern void bio_check_pages_dirty(struct bio *bio);
 248
 249 #ifndef ARCH_IMPLEMENTS_FLUSH_DCACHE_PAGE
 250 # error "You should define ARCH_IMPLEMENTS_FLUSH_DCACHE_PAGE for your platform"
 251 #endif
 252 #if ARCH_IMPLEMENTS_FLUSH_DCACHE_PAGE
 253 extern void bio_flush_dcache_pages(struct bio *bi);
 254 #else
 255 static inline void bio_flush_dcache_pages(struct bio *bi)
 256 {
 257 }
 258 #endif
 259
 260 extern struct bio *bio_copy_user(struct request_queue *, struct rq_map_data *,
 261                                  unsigned long, unsigned int, int, gfp_t);
 262 extern struct bio *bio_copy_user_iov(struct request_queue *,
 263                                      struct rq_map_data *, struct sg_iovec *,
 264                                      int, int, gfp_t);
 265 extern int bio_uncopy_user(struct bio *);
 266 void zero_fill_bio(struct bio *bio);
 267 extern struct bio_vec *bvec_alloc_bs(gfp_t, int, unsigned long *, struct bio_set *);
 268 extern void bvec_free_bs(struct bio_set *, struct bio_vec *, unsigned int);
 269 extern unsigned int bvec_nr_vecs(unsigned short idx);
 270
 271 /*
 272  * Allow queuer to specify a completion CPU for this bio
 273  */
 274 static inline void bio_set_completion_cpu(struct bio *bio, unsigned int cpu)
 275 {
 276         bio->bi_comp_cpu = cpu;
 277 }
 278
 279 /*
 280  * bio_set is used to allow other portions of the IO system to
 281  * allocate their own private memory pools for bio and iovec structures.
 282  * These memory pools in turn all allocate from the bio_slab
 283  * and the bvec_slabs[].
 284  */
 285 #define BIO_POOL_SIZE 2
 286 #define BIOVEC_NR_POOLS 6
 287 #define BIOVEC_MAX_IDX  (BIOVEC_NR_POOLS - 1)
 288
 289 struct bio_set {
 290         struct kmem_cache *bio_slab;
 291         unsigned int front_pad;
 292
 293         mempool_t *bio_pool;
 294 #if defined(CONFIG_BLK_DEV_INTEGRITY)
 295         mempool_t *bio_integrity_pool;
 296 #endif
 297         mempool_t *bvec_pool;
 298 };
 299
 300 struct biovec_slab {
 301         int nr_vecs;
 302         char *name;
 303         struct kmem_cache *slab;
 304 };
 305
 306 extern struct bio_set *fs_bio_set;
 307
 308 /*
 309  * a small number of entries is fine, not going to be performance critical.
 310  * basically we just need to survive
 311  */
 312 #define BIO_SPLIT_ENTRIES 2
 313
 314 #ifdef CONFIG_HIGHMEM
 315 /*
 316  * remember never ever reenable interrupts between a bvec_kmap_irq and
 317  * bvec_kunmap_irq!
 318  */
 319 static inline char *bvec_kmap_irq(struct bio_vec *bvec, unsigned long *flags)
 320 {
 321         unsigned long addr;
 322
 323         /*
 324          * might not be a highmem page, but the preempt/irq count
 325          * balancing is a lot nicer this way
 326          */
 327         local_irq_save(*flags);
 328         addr = (unsigned long) kmap_atomic(bvec->bv_page, KM_BIO_SRC_IRQ);
 329
 330         BUG_ON(addr & ~PAGE_MASK);
 331
 332         return (char *) addr + bvec->bv_offset;
 333 }
 334
 335 static inline void bvec_kunmap_irq(char *buffer, unsigned long *flags)
 336 {
 337         unsigned long ptr = (unsigned long) buffer & PAGE_MASK;
 338
 339         kunmap_atomic((void *) ptr, KM_BIO_SRC_IRQ);
 340         local_irq_restore(*flags);
 341 }
 342
 343 #else
 344 static inline char *bvec_kmap_irq(struct bio_vec *bvec, unsigned long *flags)
 345 {
 346         return page_address(bvec->bv_page) + bvec->bv_offset;
 347 }
 348
 349 static inline void bvec_kunmap_irq(char *buffer, unsigned long *flags)
 350 {
 351         *flags = 0;
 352 }
 353 #endif
 354
 355 static inline char *__bio_kmap_irq(struct bio *bio, unsigned short idx,
 356                                    unsigned long *flags)
 357 {
 358         return bvec_kmap_irq(bio_iovec_idx(bio, idx), flags);
 359 }
 360 #define __bio_kunmap_irq(buf, flags)    bvec_kunmap_irq(buf, flags)
 361
 362 #define bio_kmap_irq(bio, flags) \
 363         __bio_kmap_irq((bio), (bio)->bi_idx, (flags))
 364 #define bio_kunmap_irq(buf,flags)       __bio_kunmap_irq(buf, flags)
 365
 366 /*
 367  * Check whether this bio carries any data or not. A NULL bio is allowed.
 368  */
 369 static inline int bio_has_data(struct bio *bio)
 370 {
 371         return bio && bio->bi_io_vec != NULL;
 372 }
 373
 374 /*
 375  * BIO list management for use by remapping drivers (e.g. DM or MD) and loop.
 376  *
 377  * A bio_list anchors a singly-linked list of bios chained through the bi_next
 378  * member of the bio.  The bio_list also caches the last list member to allow
 379  * fast access to the tail.
 380  */
 381 struct bio_list {
 382         struct bio *head;
 383         struct bio *tail;
 384 };
 385
 386 static inline int bio_list_empty(const struct bio_list *bl)
 387 {
 388         return bl->head == NULL;
 389 }
 390
 391 static inline void bio_list_init(struct bio_list *bl)
 392 {
 393         bl->head = bl->tail = NULL;
 394 }
 395
 396 #define bio_list_for_each(bio, bl) \
 397         for (bio = (bl)->head; bio; bio = bio->bi_next)
 398
 399 static inline unsigned bio_list_size(const struct bio_list *bl)
 400 {
 401         unsigned sz = 0;
 402         struct bio *bio;
 403
 404         bio_list_for_each(bio, bl)
 405                 sz++;
 406
 407         return sz;
 408 }
 409
 410 static inline void bio_list_add(struct bio_list *bl, struct bio *bio)
 411 {
 412         bio->bi_next = NULL;
 413
 414         if (bl->tail)
 415                 bl->tail->bi_next = bio;
 416         else
 417                 bl->head = bio;
 418
 419         bl->tail = bio;
 420 }
 421
 422 static inline void bio_list_add_head(struct bio_list *bl, struct bio *bio)
 423 {
 424         bio->bi_next = bl->head;
 425
 426         bl->head = bio;
 427
 428         if (!bl->tail)
 429                 bl->tail = bio;
 430 }
 431
 432 static inline void bio_list_merge(struct bio_list *bl, struct bio_list *bl2)
 433 {
 434         if (!bl2->head)
 435                 return;
 436
 437         if (bl->tail)
 438                 bl->tail->bi_next = bl2->head;
 439         else
 440                 bl->head = bl2->head;
 441
 442         bl->tail = bl2->tail;
 443 }
 444
 445 static inline void bio_list_merge_head(struct bio_list *bl,
 446                                        struct bio_list *bl2)
 447 {
 448         if (!bl2->head)
 449                 return;
 450
 451         if (bl->head)
 452                 bl2->tail->bi_next = bl->head;
 453         else
 454                 bl->tail = bl2->tail;
 455
 456         bl->head = bl2->head;
 457 }
 458
 459 static inline struct bio *bio_list_peek(struct bio_list *bl)
 460 {
 461         return bl->head;
 462 }
 463
 464 static inline struct bio *bio_list_pop(struct bio_list *bl)
 465 {
 466         struct bio *bio = bl->head;
 467
 468         if (bio) {
 469                 bl->head = bl->head->bi_next;
 470                 if (!bl->head)
 471                         bl->tail = NULL;
 472
 473                 bio->bi_next = NULL;
 474         }
 475
 476         return bio;
 477 }
 478
 479 static inline struct bio *bio_list_get(struct bio_list *bl)
 480 {
 481         struct bio *bio = bl->head;
 482
 483         bl->head = bl->tail = NULL;
 484
 485         return bio;
 486 }
 487
 488 #if defined(CONFIG_BLK_DEV_INTEGRITY)
 489
 490 #define bip_vec_idx(bip, idx)   (&(bip->bip_vec[(idx)]))
 491 #define bip_vec(bip)            bip_vec_idx(bip, 0)
 492
 493 #define __bip_for_each_vec(bvl, bip, i, start_idx)                      \
 494         for (bvl = bip_vec_idx((bip), (start_idx)), i = (start_idx);    \
 495              i < (bip)->bip_vcnt;                                       \
 496              bvl++, i++)
 497
 498 #define bip_for_each_vec(bvl, bip, i)                                   \
 499         __bip_for_each_vec(bvl, bip, i, (bip)->bip_idx)
 500
 501 #define bio_for_each_integrity_vec(_bvl, _bio, _iter)                   \
 502         for_each_bio(_bio)                                              \
 503                 bip_for_each_vec(_bvl, _bio->bi_integrity, _iter)
 504
 505 #define bio_integrity(bio) (bio->bi_integrity != NULL)
 506
 507 extern struct bio_integrity_payload *bio_integrity_alloc_bioset(struct bio *, gfp_t, unsigned int, struct bio_set *);
 508 extern struct bio_integrity_payload *bio_integrity_alloc(struct bio *, gfp_t, unsigned int);
 509 extern void bio_integrity_free(struct bio *, struct bio_set *);
 510 extern int bio_integrity_add_page(struct bio *, struct page *, unsigned int, unsigned int);
 511 extern int bio_integrity_enabled(struct bio *bio);
 512 extern int bio_integrity_set_tag(struct bio *, void *, unsigned int);
 513 extern int bio_integrity_get_tag(struct bio *, void *, unsigned int);
 514 extern int bio_integrity_prep(struct bio *);
 515 extern void bio_integrity_endio(struct bio *, int);
 516 extern void bio_integrity_advance(struct bio *, unsigned int);
 517 extern void bio_integrity_trim(struct bio *, unsigned int, unsigned int);
 518 extern void bio_integrity_split(struct bio *, struct bio_pair *, int);
 519 extern int bio_integrity_clone(struct bio *, struct bio *, gfp_t, struct bio_set *);
 520 extern int bioset_integrity_create(struct bio_set *, int);
 521 extern void bioset_integrity_free(struct bio_set *);
 522 extern void bio_integrity_init(void);
 523
 524 #else /* CONFIG_BLK_DEV_INTEGRITY */
 525
 526 #define bio_integrity(a)                (0)
 527 #define bioset_integrity_create(a, b)   (0)
 528 #define bio_integrity_prep(a)           (0)
 529 #define bio_integrity_enabled(a)        (0)
 530 #define bio_integrity_clone(a, b, c, d) (0)
 531 #define bioset_integrity_free(a)        do { } while (0)
 532 #define bio_integrity_free(a, b)        do { } while (0)
 533 #define bio_integrity_endio(a, b)       do { } while (0)
 534 #define bio_integrity_advance(a, b)     do { } while (0)
 535 #define bio_integrity_trim(a, b, c)     do { } while (0)
 536 #define bio_integrity_split(a, b, c)    do { } while (0)
 537 #define bio_integrity_set_tag(a, b, c)  do { } while (0)
 538 #define bio_integrity_get_tag(a, b, c)  do { } while (0)
 539 #define bio_integrity_init(a)           do { } while (0)
 540
 541 #endif /* CONFIG_BLK_DEV_INTEGRITY */
 542
 543 #endif /* CONFIG_BLOCK */
 544 #endif /* __LINUX_BIO_H */