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 #define BIO_DEBUG 32 33 #ifdef BIO_DEBUG 34 #define BIO_BUG_ON BUG_ON 35 #else 36 #define BIO_BUG_ON 37 #endif 38 39 #define BIO_MAX_PAGES 256 40 #define BIO_MAX_SIZE (BIO_MAX_PAGES << PAGE_CACHE_SHIFT) 41 #define BIO_MAX_SECTORS (BIO_MAX_SIZE >> 9) 42 43 /* 44 * was unsigned short, but we might as well be ready for > 64kB I/O pages 45 */ 46 struct bio_vec { 47 struct page *bv_page; 48 unsigned int bv_len; 49 unsigned int bv_offset; 50 }; 51 52 struct bio_set; 53 struct bio; 54 struct bio_integrity_payload; 55 typedef void (bio_end_io_t) (struct bio *, int); 56 typedef void (bio_destructor_t) (struct bio *); 57 58 /* 59 * main unit of I/O for the block layer and lower layers (ie drivers and 60 * stacking drivers) 61 */ 62 struct bio { 63 sector_t bi_sector; /* device address in 512 byte 64 sectors */ 65 struct bio *bi_next; /* request queue link */ 66 struct block_device *bi_bdev; 67 unsigned long bi_flags; /* status, command, etc */ 68 unsigned long bi_rw; /* bottom bits READ/WRITE, 69 * top bits priority 70 */ 71 72 unsigned short bi_vcnt; /* how many bio_vec's */ 73 unsigned short bi_idx; /* current index into bvl_vec */ 74 75 /* Number of segments in this BIO after 76 * physical address coalescing is performed. 77 */ 78 unsigned int bi_phys_segments; 79 80 unsigned int bi_size; /* residual I/O count */ 81 82 /* 83 * To keep track of the max segment size, we account for the 84 * sizes of the first and last mergeable segments in this bio. 85 */ 86 unsigned int bi_seg_front_size; 87 unsigned int bi_seg_back_size; 88 89 unsigned int bi_max_vecs; /* max bvl_vecs we can hold */ 90 91 unsigned int bi_comp_cpu; /* completion CPU */ 92 93 atomic_t bi_cnt; /* pin count */ 94 95 struct bio_vec *bi_io_vec; /* the actual vec list */ 96 97 bio_end_io_t *bi_end_io; 98 99 void *bi_private; 100 #if defined(CONFIG_BLK_DEV_INTEGRITY) 101 struct bio_integrity_payload *bi_integrity; /* data integrity */ 102 #endif 103 104 bio_destructor_t *bi_destructor; /* destructor */ 105 106 /* 107 * We can inline a number of vecs at the end of the bio, to avoid 108 * double allocations for a small number of bio_vecs. This member 109 * MUST obviously be kept at the very end of the bio. 110 */ 111 struct bio_vec bi_inline_vecs[0]; 112 }; 113 114 /* 115 * bio flags 116 */ 117 #define BIO_UPTODATE 0 /* ok after I/O completion */ 118 #define BIO_RW_BLOCK 1 /* RW_AHEAD set, and read/write would block */ 119 #define BIO_EOF 2 /* out-out-bounds error */ 120 #define BIO_SEG_VALID 3 /* bi_phys_segments valid */ 121 #define BIO_CLONED 4 /* doesn't own data */ 122 #define BIO_BOUNCED 5 /* bio is a bounce bio */ 123 #define BIO_USER_MAPPED 6 /* contains user pages */ 124 #define BIO_EOPNOTSUPP 7 /* not supported */ 125 #define BIO_CPU_AFFINE 8 /* complete bio on same CPU as submitted */ 126 #define BIO_NULL_MAPPED 9 /* contains invalid user pages */ 127 #define BIO_FS_INTEGRITY 10 /* fs owns integrity data, not block layer */ 128 #define BIO_QUIET 11 /* Make BIO Quiet */ 129 #define bio_flagged(bio, flag) ((bio)->bi_flags & (1 << (flag))) 130 131 /* 132 * top 4 bits of bio flags indicate the pool this bio came from 133 */ 134 #define BIO_POOL_BITS (4) 135 #define BIO_POOL_OFFSET (BITS_PER_LONG - BIO_POOL_BITS) 136 #define BIO_POOL_MASK (1UL << BIO_POOL_OFFSET) 137 #define BIO_POOL_IDX(bio) ((bio)->bi_flags >> BIO_POOL_OFFSET) 138 139 /* 140 * bio bi_rw flags 141 * 142 * bit 0 -- data direction 143 * If not set, bio is a read from device. If set, it's a write to device. 144 * bit 1 -- rw-ahead when set 145 * bit 2 -- barrier 146 * Insert a serialization point in the IO queue, forcing previously 147 * submitted IO to be completed before this one is issued. 148 * bit 3 -- synchronous I/O hint: the block layer will unplug immediately 149 * Note that this does NOT indicate that the IO itself is sync, just 150 * that the block layer will not postpone issue of this IO by plugging. 151 * bit 4 -- metadata request 152 * Used for tracing to differentiate metadata and data IO. May also 153 * get some preferential treatment in the IO scheduler 154 * bit 5 -- discard sectors 155 * Informs the lower level device that this range of sectors is no longer 156 * used by the file system and may thus be freed by the device. Used 157 * for flash based storage. 158 * bit 6 -- fail fast device errors 159 * bit 7 -- fail fast transport errors 160 * bit 8 -- fail fast driver errors 161 * Don't want driver retries for any fast fail whatever the reason. 162 */ 163 #define BIO_RW 0 /* Must match RW in req flags (blkdev.h) */ 164 #define BIO_RW_AHEAD 1 /* Must match FAILFAST in req flags */ 165 #define BIO_RW_BARRIER 2 166 #define BIO_RW_SYNCIO 3 167 #define BIO_RW_UNPLUG 4 168 #define BIO_RW_META 5 169 #define BIO_RW_DISCARD 6 170 #define BIO_RW_FAILFAST_DEV 7 171 #define BIO_RW_FAILFAST_TRANSPORT 8 172 #define BIO_RW_FAILFAST_DRIVER 9 173 174 #define bio_rw_flagged(bio, flag) ((bio)->bi_rw & (1 << (flag))) 175 176 /* 177 * Old defines, these should eventually be replaced by direct usage of 178 * bio_rw_flagged() 179 */ 180 #define bio_barrier(bio) bio_rw_flagged(bio, BIO_RW_BARRIER) 181 #define bio_sync(bio) bio_rw_flagged(bio, BIO_RW_SYNCIO) 182 #define bio_unplug(bio) bio_rw_flagged(bio, BIO_RW_UNPLUG) 183 #define bio_failfast_dev(bio) bio_rw_flagged(bio, BIO_RW_FAILFAST_DEV) 184 #define bio_failfast_transport(bio) \ 185 bio_rw_flagged(bio, BIO_RW_FAILFAST_TRANSPORT) 186 #define bio_failfast_driver(bio) \ 187 bio_rw_flagged(bio, BIO_RW_FAILFAST_DRIVER) 188 #define bio_rw_ahead(bio) bio_rw_flagged(bio, BIO_RW_AHEAD) 189 #define bio_rw_meta(bio) bio_rw_flagged(bio, BIO_RW_META) 190 #define bio_discard(bio) bio_rw_flagged(bio, BIO_RW_DISCARD) 191 192 /* 193 * upper 16 bits of bi_rw define the io priority of this bio 194 */ 195 #define BIO_PRIO_SHIFT (8 * sizeof(unsigned long) - IOPRIO_BITS) 196 #define bio_prio(bio) ((bio)->bi_rw >> BIO_PRIO_SHIFT) 197 #define bio_prio_valid(bio) ioprio_valid(bio_prio(bio)) 198 199 #define bio_set_prio(bio, prio) do { \ 200 WARN_ON(prio >= (1 << IOPRIO_BITS)); \ 201 (bio)->bi_rw &= ((1UL << BIO_PRIO_SHIFT) - 1); \ 202 (bio)->bi_rw |= ((unsigned long) (prio) << BIO_PRIO_SHIFT); \ 203 } while (0) 204 205 /* 206 * various member access, note that bio_data should of course not be used 207 * on highmem page vectors 208 */ 209 #define bio_iovec_idx(bio, idx) (&((bio)->bi_io_vec[(idx)])) 210 #define bio_iovec(bio) bio_iovec_idx((bio), (bio)->bi_idx) 211 #define bio_page(bio) bio_iovec((bio))->bv_page 212 #define bio_offset(bio) bio_iovec((bio))->bv_offset 213 #define bio_segments(bio) ((bio)->bi_vcnt - (bio)->bi_idx) 214 #define bio_sectors(bio) ((bio)->bi_size >> 9) 215 #define bio_empty_barrier(bio) (bio_barrier(bio) && !bio_has_data(bio) && !bio_discard(bio)) 216 217 static inline unsigned int bio_cur_sectors(struct bio *bio) 218 { 219 if (bio->bi_vcnt) 220 return bio_iovec(bio)->bv_len >> 9; 221 else /* dataless requests such as discard */ 222 return bio->bi_size >> 9; 223 } 224 225 static inline void *bio_data(struct bio *bio) 226 { 227 if (bio->bi_vcnt) 228 return page_address(bio_page(bio)) + bio_offset(bio); 229 230 return NULL; 231 } 232 233 static inline int bio_has_allocated_vec(struct bio *bio) 234 { 235 return bio->bi_io_vec && bio->bi_io_vec != bio->bi_inline_vecs; 236 } 237 238 /* 239 * will die 240 */ 241 #define bio_to_phys(bio) (page_to_phys(bio_page((bio))) + (unsigned long) bio_offset((bio))) 242 #define bvec_to_phys(bv) (page_to_phys((bv)->bv_page) + (unsigned long) (bv)->bv_offset) 243 244 /* 245 * queues that have highmem support enabled may still need to revert to 246 * PIO transfers occasionally and thus map high pages temporarily. For 247 * permanent PIO fall back, user is probably better off disabling highmem 248 * I/O completely on that queue (see ide-dma for example) 249 */ 250 #define __bio_kmap_atomic(bio, idx, kmtype) \ 251 (kmap_atomic(bio_iovec_idx((bio), (idx))->bv_page, kmtype) + \ 252 bio_iovec_idx((bio), (idx))->bv_offset) 253 254 #define __bio_kunmap_atomic(addr, kmtype) kunmap_atomic(addr, kmtype) 255 256 /* 257 * merge helpers etc 258 */ 259 260 #define __BVEC_END(bio) bio_iovec_idx((bio), (bio)->bi_vcnt - 1) 261 #define __BVEC_START(bio) bio_iovec_idx((bio), (bio)->bi_idx) 262 263 /* Default implementation of BIOVEC_PHYS_MERGEABLE */ 264 #define __BIOVEC_PHYS_MERGEABLE(vec1, vec2) \ 265 ((bvec_to_phys((vec1)) + (vec1)->bv_len) == bvec_to_phys((vec2))) 266 267 /* 268 * allow arch override, for eg virtualized architectures (put in asm/io.h) 269 */ 270 #ifndef BIOVEC_PHYS_MERGEABLE 271 #define BIOVEC_PHYS_MERGEABLE(vec1, vec2) \ 272 __BIOVEC_PHYS_MERGEABLE(vec1, vec2) 273 #endif 274 275 #define __BIO_SEG_BOUNDARY(addr1, addr2, mask) \ 276 (((addr1) | (mask)) == (((addr2) - 1) | (mask))) 277 #define BIOVEC_SEG_BOUNDARY(q, b1, b2) \ 278 __BIO_SEG_BOUNDARY(bvec_to_phys((b1)), bvec_to_phys((b2)) + (b2)->bv_len, (q)->seg_boundary_mask) 279 #define BIO_SEG_BOUNDARY(q, b1, b2) \ 280 BIOVEC_SEG_BOUNDARY((q), __BVEC_END((b1)), __BVEC_START((b2))) 281 282 #define bio_io_error(bio) bio_endio((bio), -EIO) 283 284 /* 285 * drivers should not use the __ version unless they _really_ want to 286 * run through the entire bio and not just pending pieces 287 */ 288 #define __bio_for_each_segment(bvl, bio, i, start_idx) \ 289 for (bvl = bio_iovec_idx((bio), (start_idx)), i = (start_idx); \ 290 i < (bio)->bi_vcnt; \ 291 bvl++, i++) 292 293 #define bio_for_each_segment(bvl, bio, i) \ 294 __bio_for_each_segment(bvl, bio, i, (bio)->bi_idx) 295 296 /* 297 * get a reference to a bio, so it won't disappear. the intended use is 298 * something like: 299 * 300 * bio_get(bio); 301 * submit_bio(rw, bio); 302 * if (bio->bi_flags ...) 303 * do_something 304 * bio_put(bio); 305 * 306 * without the bio_get(), it could potentially complete I/O before submit_bio 307 * returns. and then bio would be freed memory when if (bio->bi_flags ...) 308 * runs 309 */ 310 #define bio_get(bio) atomic_inc(&(bio)->bi_cnt) 311 312 #if defined(CONFIG_BLK_DEV_INTEGRITY) 313 /* 314 * bio integrity payload 315 */ 316 struct bio_integrity_payload { 317 struct bio *bip_bio; /* parent bio */ 318 struct bio_vec *bip_vec; /* integrity data vector */ 319 320 sector_t bip_sector; /* virtual start sector */ 321 322 void *bip_buf; /* generated integrity data */ 323 bio_end_io_t *bip_end_io; /* saved I/O completion fn */ 324 325 unsigned int bip_size; 326 327 unsigned short bip_pool; /* pool the ivec came from */ 328 unsigned short bip_vcnt; /* # of integrity bio_vecs */ 329 unsigned short bip_idx; /* current bip_vec index */ 330 331 struct work_struct bip_work; /* I/O completion */ 332 }; 333 #endif /* CONFIG_BLK_DEV_INTEGRITY */ 334 335 /* 336 * A bio_pair is used when we need to split a bio. 337 * This can only happen for a bio that refers to just one 338 * page of data, and in the unusual situation when the 339 * page crosses a chunk/device boundary 340 * 341 * The address of the master bio is stored in bio1.bi_private 342 * The address of the pool the pair was allocated from is stored 343 * in bio2.bi_private 344 */ 345 struct bio_pair { 346 struct bio bio1, bio2; 347 struct bio_vec bv1, bv2; 348 #if defined(CONFIG_BLK_DEV_INTEGRITY) 349 struct bio_integrity_payload bip1, bip2; 350 struct bio_vec iv1, iv2; 351 #endif 352 atomic_t cnt; 353 int error; 354 }; 355 extern struct bio_pair *bio_split(struct bio *bi, int first_sectors); 356 extern void bio_pair_release(struct bio_pair *dbio); 357 358 extern struct bio_set *bioset_create(unsigned int, unsigned int); 359 extern void bioset_free(struct bio_set *); 360 361 extern struct bio *bio_alloc(gfp_t, int); 362 extern struct bio *bio_kmalloc(gfp_t, int); 363 extern struct bio *bio_alloc_bioset(gfp_t, int, struct bio_set *); 364 extern void bio_put(struct bio *); 365 extern void bio_free(struct bio *, struct bio_set *); 366 367 extern void bio_endio(struct bio *, int); 368 struct request_queue; 369 extern int bio_phys_segments(struct request_queue *, struct bio *); 370 371 extern void __bio_clone(struct bio *, struct bio *); 372 extern struct bio *bio_clone(struct bio *, gfp_t); 373 374 extern void bio_init(struct bio *); 375 376 extern int bio_add_page(struct bio *, struct page *, unsigned int,unsigned int); 377 extern int bio_add_pc_page(struct request_queue *, struct bio *, struct page *, 378 unsigned int, unsigned int); 379 extern int bio_get_nr_vecs(struct block_device *); 380 extern sector_t bio_sector_offset(struct bio *, unsigned short, unsigned int); 381 extern struct bio *bio_map_user(struct request_queue *, struct block_device *, 382 unsigned long, unsigned int, int, gfp_t); 383 struct sg_iovec; 384 struct rq_map_data; 385 extern struct bio *bio_map_user_iov(struct request_queue *, 386 struct block_device *, 387 struct sg_iovec *, int, int, gfp_t); 388 extern void bio_unmap_user(struct bio *); 389 extern struct bio *bio_map_kern(struct request_queue *, void *, unsigned int, 390 gfp_t); 391 extern struct bio *bio_copy_kern(struct request_queue *, void *, unsigned int, 392 gfp_t, int); 393 extern void bio_set_pages_dirty(struct bio *bio); 394 extern void bio_check_pages_dirty(struct bio *bio); 395 extern struct bio *bio_copy_user(struct request_queue *, struct rq_map_data *, 396 unsigned long, unsigned int, int, gfp_t); 397 extern struct bio *bio_copy_user_iov(struct request_queue *, 398 struct rq_map_data *, struct sg_iovec *, 399 int, int, gfp_t); 400 extern int bio_uncopy_user(struct bio *); 401 void zero_fill_bio(struct bio *bio); 402 extern struct bio_vec *bvec_alloc_bs(gfp_t, int, unsigned long *, struct bio_set *); 403 extern void bvec_free_bs(struct bio_set *, struct bio_vec *, unsigned int); 404 extern unsigned int bvec_nr_vecs(unsigned short idx); 405 406 /* 407 * Allow queuer to specify a completion CPU for this bio 408 */ 409 static inline void bio_set_completion_cpu(struct bio *bio, unsigned int cpu) 410 { 411 bio->bi_comp_cpu = cpu; 412 } 413 414 /* 415 * bio_set is used to allow other portions of the IO system to 416 * allocate their own private memory pools for bio and iovec structures. 417 * These memory pools in turn all allocate from the bio_slab 418 * and the bvec_slabs[]. 419 */ 420 #define BIO_POOL_SIZE 2 421 #define BIOVEC_NR_POOLS 6 422 #define BIOVEC_MAX_IDX (BIOVEC_NR_POOLS - 1) 423 424 struct bio_set { 425 struct kmem_cache *bio_slab; 426 unsigned int front_pad; 427 428 mempool_t *bio_pool; 429 mempool_t *bvec_pool; 430 }; 431 432 struct biovec_slab { 433 int nr_vecs; 434 char *name; 435 struct kmem_cache *slab; 436 }; 437 438 extern struct bio_set *fs_bio_set; 439 extern struct biovec_slab bvec_slabs[BIOVEC_NR_POOLS] __read_mostly; 440 441 /* 442 * a small number of entries is fine, not going to be performance critical. 443 * basically we just need to survive 444 */ 445 #define BIO_SPLIT_ENTRIES 2 446 447 #ifdef CONFIG_HIGHMEM 448 /* 449 * remember never ever reenable interrupts between a bvec_kmap_irq and 450 * bvec_kunmap_irq! 451 * 452 * This function MUST be inlined - it plays with the CPU interrupt flags. 453 */ 454 static __always_inline char *bvec_kmap_irq(struct bio_vec *bvec, 455 unsigned long *flags) 456 { 457 unsigned long addr; 458 459 /* 460 * might not be a highmem page, but the preempt/irq count 461 * balancing is a lot nicer this way 462 */ 463 local_irq_save(*flags); 464 addr = (unsigned long) kmap_atomic(bvec->bv_page, KM_BIO_SRC_IRQ); 465 466 BUG_ON(addr & ~PAGE_MASK); 467 468 return (char *) addr + bvec->bv_offset; 469 } 470 471 static __always_inline void bvec_kunmap_irq(char *buffer, 472 unsigned long *flags) 473 { 474 unsigned long ptr = (unsigned long) buffer & PAGE_MASK; 475 476 kunmap_atomic((void *) ptr, KM_BIO_SRC_IRQ); 477 local_irq_restore(*flags); 478 } 479 480 #else 481 #define bvec_kmap_irq(bvec, flags) (page_address((bvec)->bv_page) + (bvec)->bv_offset) 482 #define bvec_kunmap_irq(buf, flags) do { *(flags) = 0; } while (0) 483 #endif 484 485 static inline char *__bio_kmap_irq(struct bio *bio, unsigned short idx, 486 unsigned long *flags) 487 { 488 return bvec_kmap_irq(bio_iovec_idx(bio, idx), flags); 489 } 490 #define __bio_kunmap_irq(buf, flags) bvec_kunmap_irq(buf, flags) 491 492 #define bio_kmap_irq(bio, flags) \ 493 __bio_kmap_irq((bio), (bio)->bi_idx, (flags)) 494 #define bio_kunmap_irq(buf,flags) __bio_kunmap_irq(buf, flags) 495 496 /* 497 * Check whether this bio carries any data or not. A NULL bio is allowed. 498 */ 499 static inline int bio_has_data(struct bio *bio) 500 { 501 return bio && bio->bi_io_vec != NULL; 502 } 503 504 #if defined(CONFIG_BLK_DEV_INTEGRITY) 505 506 #define bip_vec_idx(bip, idx) (&(bip->bip_vec[(idx)])) 507 #define bip_vec(bip) bip_vec_idx(bip, 0) 508 509 #define __bip_for_each_vec(bvl, bip, i, start_idx) \ 510 for (bvl = bip_vec_idx((bip), (start_idx)), i = (start_idx); \ 511 i < (bip)->bip_vcnt; \ 512 bvl++, i++) 513 514 #define bip_for_each_vec(bvl, bip, i) \ 515 __bip_for_each_vec(bvl, bip, i, (bip)->bip_idx) 516 517 #define bio_integrity(bio) (bio->bi_integrity != NULL) 518 519 extern struct bio_integrity_payload *bio_integrity_alloc(struct bio *, gfp_t, unsigned int); 520 extern void bio_integrity_free(struct bio *); 521 extern int bio_integrity_add_page(struct bio *, struct page *, unsigned int, unsigned int); 522 extern int bio_integrity_enabled(struct bio *bio); 523 extern int bio_integrity_set_tag(struct bio *, void *, unsigned int); 524 extern int bio_integrity_get_tag(struct bio *, void *, unsigned int); 525 extern int bio_integrity_prep(struct bio *); 526 extern void bio_integrity_endio(struct bio *, int); 527 extern void bio_integrity_advance(struct bio *, unsigned int); 528 extern void bio_integrity_trim(struct bio *, unsigned int, unsigned int); 529 extern void bio_integrity_split(struct bio *, struct bio_pair *, int); 530 extern int bio_integrity_clone(struct bio *, struct bio *, gfp_t); 531 532 #else /* CONFIG_BLK_DEV_INTEGRITY */ 533 534 #define bio_integrity(a) (0) 535 #define bio_integrity_prep(a) (0) 536 #define bio_integrity_enabled(a) (0) 537 #define bio_integrity_clone(a, b, c) (0) 538 #define bio_integrity_free(a) do { } while (0) 539 #define bio_integrity_endio(a, b) do { } while (0) 540 #define bio_integrity_advance(a, b) do { } while (0) 541 #define bio_integrity_trim(a, b, c) do { } while (0) 542 #define bio_integrity_split(a, b, c) do { } while (0) 543 #define bio_integrity_set_tag(a, b, c) do { } while (0) 544 #define bio_integrity_get_tag(a, b, c) do { } while (0) 545 546 #endif /* CONFIG_BLK_DEV_INTEGRITY */ 547 548 #endif /* CONFIG_BLOCK */ 549 #endif /* __LINUX_BIO_H */ 550