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 extern struct biovec_slab bvec_slabs[BIOVEC_NR_POOLS] __read_mostly; 308 309 /* 310 * a small number of entries is fine, not going to be performance critical. 311 * basically we just need to survive 312 */ 313 #define BIO_SPLIT_ENTRIES 2 314 315 #ifdef CONFIG_HIGHMEM 316 /* 317 * remember never ever reenable interrupts between a bvec_kmap_irq and 318 * bvec_kunmap_irq! 319 */ 320 static inline char *bvec_kmap_irq(struct bio_vec *bvec, unsigned long *flags) 321 { 322 unsigned long addr; 323 324 /* 325 * might not be a highmem page, but the preempt/irq count 326 * balancing is a lot nicer this way 327 */ 328 local_irq_save(*flags); 329 addr = (unsigned long) kmap_atomic(bvec->bv_page, KM_BIO_SRC_IRQ); 330 331 BUG_ON(addr & ~PAGE_MASK); 332 333 return (char *) addr + bvec->bv_offset; 334 } 335 336 static inline void bvec_kunmap_irq(char *buffer, unsigned long *flags) 337 { 338 unsigned long ptr = (unsigned long) buffer & PAGE_MASK; 339 340 kunmap_atomic((void *) ptr, KM_BIO_SRC_IRQ); 341 local_irq_restore(*flags); 342 } 343 344 #else 345 static inline char *bvec_kmap_irq(struct bio_vec *bvec, unsigned long *flags) 346 { 347 return page_address(bvec->bv_page) + bvec->bv_offset; 348 } 349 350 static inline void bvec_kunmap_irq(char *buffer, unsigned long *flags) 351 { 352 *flags = 0; 353 } 354 #endif 355 356 static inline char *__bio_kmap_irq(struct bio *bio, unsigned short idx, 357 unsigned long *flags) 358 { 359 return bvec_kmap_irq(bio_iovec_idx(bio, idx), flags); 360 } 361 #define __bio_kunmap_irq(buf, flags) bvec_kunmap_irq(buf, flags) 362 363 #define bio_kmap_irq(bio, flags) \ 364 __bio_kmap_irq((bio), (bio)->bi_idx, (flags)) 365 #define bio_kunmap_irq(buf,flags) __bio_kunmap_irq(buf, flags) 366 367 /* 368 * Check whether this bio carries any data or not. A NULL bio is allowed. 369 */ 370 static inline int bio_has_data(struct bio *bio) 371 { 372 return bio && bio->bi_io_vec != NULL; 373 } 374 375 /* 376 * BIO list management for use by remapping drivers (e.g. DM or MD) and loop. 377 * 378 * A bio_list anchors a singly-linked list of bios chained through the bi_next 379 * member of the bio. The bio_list also caches the last list member to allow 380 * fast access to the tail. 381 */ 382 struct bio_list { 383 struct bio *head; 384 struct bio *tail; 385 }; 386 387 static inline int bio_list_empty(const struct bio_list *bl) 388 { 389 return bl->head == NULL; 390 } 391 392 static inline void bio_list_init(struct bio_list *bl) 393 { 394 bl->head = bl->tail = NULL; 395 } 396 397 #define bio_list_for_each(bio, bl) \ 398 for (bio = (bl)->head; bio; bio = bio->bi_next) 399 400 static inline unsigned bio_list_size(const struct bio_list *bl) 401 { 402 unsigned sz = 0; 403 struct bio *bio; 404 405 bio_list_for_each(bio, bl) 406 sz++; 407 408 return sz; 409 } 410 411 static inline void bio_list_add(struct bio_list *bl, struct bio *bio) 412 { 413 bio->bi_next = NULL; 414 415 if (bl->tail) 416 bl->tail->bi_next = bio; 417 else 418 bl->head = bio; 419 420 bl->tail = bio; 421 } 422 423 static inline void bio_list_add_head(struct bio_list *bl, struct bio *bio) 424 { 425 bio->bi_next = bl->head; 426 427 bl->head = bio; 428 429 if (!bl->tail) 430 bl->tail = bio; 431 } 432 433 static inline void bio_list_merge(struct bio_list *bl, struct bio_list *bl2) 434 { 435 if (!bl2->head) 436 return; 437 438 if (bl->tail) 439 bl->tail->bi_next = bl2->head; 440 else 441 bl->head = bl2->head; 442 443 bl->tail = bl2->tail; 444 } 445 446 static inline void bio_list_merge_head(struct bio_list *bl, 447 struct bio_list *bl2) 448 { 449 if (!bl2->head) 450 return; 451 452 if (bl->head) 453 bl2->tail->bi_next = bl->head; 454 else 455 bl->tail = bl2->tail; 456 457 bl->head = bl2->head; 458 } 459 460 static inline struct bio *bio_list_peek(struct bio_list *bl) 461 { 462 return bl->head; 463 } 464 465 static inline struct bio *bio_list_pop(struct bio_list *bl) 466 { 467 struct bio *bio = bl->head; 468 469 if (bio) { 470 bl->head = bl->head->bi_next; 471 if (!bl->head) 472 bl->tail = NULL; 473 474 bio->bi_next = NULL; 475 } 476 477 return bio; 478 } 479 480 static inline struct bio *bio_list_get(struct bio_list *bl) 481 { 482 struct bio *bio = bl->head; 483 484 bl->head = bl->tail = NULL; 485 486 return bio; 487 } 488 489 #if defined(CONFIG_BLK_DEV_INTEGRITY) 490 491 #define bip_vec_idx(bip, idx) (&(bip->bip_vec[(idx)])) 492 #define bip_vec(bip) bip_vec_idx(bip, 0) 493 494 #define __bip_for_each_vec(bvl, bip, i, start_idx) \ 495 for (bvl = bip_vec_idx((bip), (start_idx)), i = (start_idx); \ 496 i < (bip)->bip_vcnt; \ 497 bvl++, i++) 498 499 #define bip_for_each_vec(bvl, bip, i) \ 500 __bip_for_each_vec(bvl, bip, i, (bip)->bip_idx) 501 502 #define bio_for_each_integrity_vec(_bvl, _bio, _iter) \ 503 for_each_bio(_bio) \ 504 bip_for_each_vec(_bvl, _bio->bi_integrity, _iter) 505 506 #define bio_integrity(bio) (bio->bi_integrity != NULL) 507 508 extern struct bio_integrity_payload *bio_integrity_alloc_bioset(struct bio *, gfp_t, unsigned int, struct bio_set *); 509 extern struct bio_integrity_payload *bio_integrity_alloc(struct bio *, gfp_t, unsigned int); 510 extern void bio_integrity_free(struct bio *, struct bio_set *); 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, struct bio_set *); 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 #define bio_integrity(a) (0) 528 #define bioset_integrity_create(a, b) (0) 529 #define bio_integrity_prep(a) (0) 530 #define bio_integrity_enabled(a) (0) 531 #define bio_integrity_clone(a, b, c, d) (0) 532 #define bioset_integrity_free(a) do { } while (0) 533 #define bio_integrity_free(a, b) do { } while (0) 534 #define bio_integrity_endio(a, b) do { } while (0) 535 #define bio_integrity_advance(a, b) do { } while (0) 536 #define bio_integrity_trim(a, b, c) do { } while (0) 537 #define bio_integrity_split(a, b, c) do { } while (0) 538 #define bio_integrity_set_tag(a, b, c) do { } while (0) 539 #define bio_integrity_get_tag(a, b, c) do { } while (0) 540 #define bio_integrity_init(a) do { } while (0) 541 542 #endif /* CONFIG_BLK_DEV_INTEGRITY */ 543 544 #endif /* CONFIG_BLOCK */ 545 #endif /* __LINUX_BIO_H */ 546