1 /* 2 * 2.5 block I/O model 3 * 4 * Copyright (C) 2001 Jens Axboe <[email protected]> 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 /* Platforms may set this to teach the BIO layer about IOMMU hardware. */ 30 #include <asm/io.h> 31 32 #if defined(BIO_VMERGE_MAX_SIZE) && defined(BIO_VMERGE_BOUNDARY) 33 #define BIOVEC_VIRT_START_SIZE(x) (bvec_to_phys(x) & (BIO_VMERGE_BOUNDARY - 1)) 34 #define BIOVEC_VIRT_OVERSIZE(x) ((x) > BIO_VMERGE_MAX_SIZE) 35 #else 36 #define BIOVEC_VIRT_START_SIZE(x) 0 37 #define BIOVEC_VIRT_OVERSIZE(x) 0 38 #endif 39 40 #ifndef BIO_VMERGE_BOUNDARY 41 #define BIO_VMERGE_BOUNDARY 0 42 #endif 43 44 #define BIO_DEBUG 45 46 #ifdef BIO_DEBUG 47 #define BIO_BUG_ON BUG_ON 48 #else 49 #define BIO_BUG_ON 50 #endif 51 52 #define BIO_MAX_PAGES 256 53 #define BIO_MAX_SIZE (BIO_MAX_PAGES << PAGE_CACHE_SHIFT) 54 #define BIO_MAX_SECTORS (BIO_MAX_SIZE >> 9) 55 56 /* 57 * was unsigned short, but we might as well be ready for > 64kB I/O pages 58 */ 59 struct bio_vec { 60 struct page *bv_page; 61 unsigned int bv_len; 62 unsigned int bv_offset; 63 }; 64 65 struct bio_set; 66 struct bio; 67 struct bio_integrity_payload; 68 typedef void (bio_end_io_t) (struct bio *, int); 69 typedef void (bio_destructor_t) (struct bio *); 70 71 /* 72 * main unit of I/O for the block layer and lower layers (ie drivers and 73 * stacking drivers) 74 */ 75 struct bio { 76 sector_t bi_sector; /* device address in 512 byte 77 sectors */ 78 struct bio *bi_next; /* request queue link */ 79 struct block_device *bi_bdev; 80 unsigned long bi_flags; /* status, command, etc */ 81 unsigned long bi_rw; /* bottom bits READ/WRITE, 82 * top bits priority 83 */ 84 85 unsigned short bi_vcnt; /* how many bio_vec's */ 86 unsigned short bi_idx; /* current index into bvl_vec */ 87 88 /* Number of segments in this BIO after 89 * physical address coalescing is performed. 90 */ 91 unsigned short bi_phys_segments; 92 93 /* Number of segments after physical and DMA remapping 94 * hardware coalescing is performed. 95 */ 96 unsigned short bi_hw_segments; 97 98 unsigned int bi_size; /* residual I/O count */ 99 100 /* 101 * To keep track of the max hw size, we account for the 102 * sizes of the first and last virtually mergeable segments 103 * in this bio 104 */ 105 unsigned int bi_hw_front_size; 106 unsigned int bi_hw_back_size; 107 108 unsigned int bi_max_vecs; /* max bvl_vecs we can hold */ 109 110 struct bio_vec *bi_io_vec; /* the actual vec list */ 111 112 bio_end_io_t *bi_end_io; 113 atomic_t bi_cnt; /* pin count */ 114 115 void *bi_private; 116 #if defined(CONFIG_BLK_DEV_INTEGRITY) 117 struct bio_integrity_payload *bi_integrity; /* data integrity */ 118 #endif 119 120 bio_destructor_t *bi_destructor; /* destructor */ 121 }; 122 123 /* 124 * bio flags 125 */ 126 #define BIO_UPTODATE 0 /* ok after I/O completion */ 127 #define BIO_RW_BLOCK 1 /* RW_AHEAD set, and read/write would block */ 128 #define BIO_EOF 2 /* out-out-bounds error */ 129 #define BIO_SEG_VALID 3 /* nr_hw_seg valid */ 130 #define BIO_CLONED 4 /* doesn't own data */ 131 #define BIO_BOUNCED 5 /* bio is a bounce bio */ 132 #define BIO_USER_MAPPED 6 /* contains user pages */ 133 #define BIO_EOPNOTSUPP 7 /* not supported */ 134 #define bio_flagged(bio, flag) ((bio)->bi_flags & (1 << (flag))) 135 136 /* 137 * top 4 bits of bio flags indicate the pool this bio came from 138 */ 139 #define BIO_POOL_BITS (4) 140 #define BIO_POOL_OFFSET (BITS_PER_LONG - BIO_POOL_BITS) 141 #define BIO_POOL_MASK (1UL << BIO_POOL_OFFSET) 142 #define BIO_POOL_IDX(bio) ((bio)->bi_flags >> BIO_POOL_OFFSET) 143 144 /* 145 * bio bi_rw flags 146 * 147 * bit 0 -- read (not set) or write (set) 148 * bit 1 -- rw-ahead when set 149 * bit 2 -- barrier 150 * bit 3 -- fail fast, don't want low level driver retries 151 * bit 4 -- synchronous I/O hint: the block layer will unplug immediately 152 */ 153 #define BIO_RW 0 154 #define BIO_RW_AHEAD 1 155 #define BIO_RW_BARRIER 2 156 #define BIO_RW_FAILFAST 3 157 #define BIO_RW_SYNC 4 158 #define BIO_RW_META 5 159 160 /* 161 * upper 16 bits of bi_rw define the io priority of this bio 162 */ 163 #define BIO_PRIO_SHIFT (8 * sizeof(unsigned long) - IOPRIO_BITS) 164 #define bio_prio(bio) ((bio)->bi_rw >> BIO_PRIO_SHIFT) 165 #define bio_prio_valid(bio) ioprio_valid(bio_prio(bio)) 166 167 #define bio_set_prio(bio, prio) do { \ 168 WARN_ON(prio >= (1 << IOPRIO_BITS)); \ 169 (bio)->bi_rw &= ((1UL << BIO_PRIO_SHIFT) - 1); \ 170 (bio)->bi_rw |= ((unsigned long) (prio) << BIO_PRIO_SHIFT); \ 171 } while (0) 172 173 /* 174 * various member access, note that bio_data should of course not be used 175 * on highmem page vectors 176 */ 177 #define bio_iovec_idx(bio, idx) (&((bio)->bi_io_vec[(idx)])) 178 #define bio_iovec(bio) bio_iovec_idx((bio), (bio)->bi_idx) 179 #define bio_page(bio) bio_iovec((bio))->bv_page 180 #define bio_offset(bio) bio_iovec((bio))->bv_offset 181 #define bio_segments(bio) ((bio)->bi_vcnt - (bio)->bi_idx) 182 #define bio_sectors(bio) ((bio)->bi_size >> 9) 183 #define bio_barrier(bio) ((bio)->bi_rw & (1 << BIO_RW_BARRIER)) 184 #define bio_sync(bio) ((bio)->bi_rw & (1 << BIO_RW_SYNC)) 185 #define bio_failfast(bio) ((bio)->bi_rw & (1 << BIO_RW_FAILFAST)) 186 #define bio_rw_ahead(bio) ((bio)->bi_rw & (1 << BIO_RW_AHEAD)) 187 #define bio_rw_meta(bio) ((bio)->bi_rw & (1 << BIO_RW_META)) 188 #define bio_empty_barrier(bio) (bio_barrier(bio) && !(bio)->bi_size) 189 190 static inline unsigned int bio_cur_sectors(struct bio *bio) 191 { 192 if (bio->bi_vcnt) 193 return bio_iovec(bio)->bv_len >> 9; 194 195 return 0; 196 } 197 198 static inline void *bio_data(struct bio *bio) 199 { 200 if (bio->bi_vcnt) 201 return page_address(bio_page(bio)) + bio_offset(bio); 202 203 return NULL; 204 } 205 206 /* 207 * will die 208 */ 209 #define bio_to_phys(bio) (page_to_phys(bio_page((bio))) + (unsigned long) bio_offset((bio))) 210 #define bvec_to_phys(bv) (page_to_phys((bv)->bv_page) + (unsigned long) (bv)->bv_offset) 211 212 /* 213 * queues that have highmem support enabled may still need to revert to 214 * PIO transfers occasionally and thus map high pages temporarily. For 215 * permanent PIO fall back, user is probably better off disabling highmem 216 * I/O completely on that queue (see ide-dma for example) 217 */ 218 #define __bio_kmap_atomic(bio, idx, kmtype) \ 219 (kmap_atomic(bio_iovec_idx((bio), (idx))->bv_page, kmtype) + \ 220 bio_iovec_idx((bio), (idx))->bv_offset) 221 222 #define __bio_kunmap_atomic(addr, kmtype) kunmap_atomic(addr, kmtype) 223 224 /* 225 * merge helpers etc 226 */ 227 228 #define __BVEC_END(bio) bio_iovec_idx((bio), (bio)->bi_vcnt - 1) 229 #define __BVEC_START(bio) bio_iovec_idx((bio), (bio)->bi_idx) 230 231 /* 232 * allow arch override, for eg virtualized architectures (put in asm/io.h) 233 */ 234 #ifndef BIOVEC_PHYS_MERGEABLE 235 #define BIOVEC_PHYS_MERGEABLE(vec1, vec2) \ 236 ((bvec_to_phys((vec1)) + (vec1)->bv_len) == bvec_to_phys((vec2))) 237 #endif 238 239 #define BIOVEC_VIRT_MERGEABLE(vec1, vec2) \ 240 ((((bvec_to_phys((vec1)) + (vec1)->bv_len) | bvec_to_phys((vec2))) & (BIO_VMERGE_BOUNDARY - 1)) == 0) 241 #define __BIO_SEG_BOUNDARY(addr1, addr2, mask) \ 242 (((addr1) | (mask)) == (((addr2) - 1) | (mask))) 243 #define BIOVEC_SEG_BOUNDARY(q, b1, b2) \ 244 __BIO_SEG_BOUNDARY(bvec_to_phys((b1)), bvec_to_phys((b2)) + (b2)->bv_len, (q)->seg_boundary_mask) 245 #define BIO_SEG_BOUNDARY(q, b1, b2) \ 246 BIOVEC_SEG_BOUNDARY((q), __BVEC_END((b1)), __BVEC_START((b2))) 247 248 #define bio_io_error(bio) bio_endio((bio), -EIO) 249 250 /* 251 * drivers should not use the __ version unless they _really_ want to 252 * run through the entire bio and not just pending pieces 253 */ 254 #define __bio_for_each_segment(bvl, bio, i, start_idx) \ 255 for (bvl = bio_iovec_idx((bio), (start_idx)), i = (start_idx); \ 256 i < (bio)->bi_vcnt; \ 257 bvl++, i++) 258 259 #define bio_for_each_segment(bvl, bio, i) \ 260 __bio_for_each_segment(bvl, bio, i, (bio)->bi_idx) 261 262 /* 263 * get a reference to a bio, so it won't disappear. the intended use is 264 * something like: 265 * 266 * bio_get(bio); 267 * submit_bio(rw, bio); 268 * if (bio->bi_flags ...) 269 * do_something 270 * bio_put(bio); 271 * 272 * without the bio_get(), it could potentially complete I/O before submit_bio 273 * returns. and then bio would be freed memory when if (bio->bi_flags ...) 274 * runs 275 */ 276 #define bio_get(bio) atomic_inc(&(bio)->bi_cnt) 277 278 #if defined(CONFIG_BLK_DEV_INTEGRITY) 279 /* 280 * bio integrity payload 281 */ 282 struct bio_integrity_payload { 283 struct bio *bip_bio; /* parent bio */ 284 struct bio_vec *bip_vec; /* integrity data vector */ 285 286 sector_t bip_sector; /* virtual start sector */ 287 288 void *bip_buf; /* generated integrity data */ 289 bio_end_io_t *bip_end_io; /* saved I/O completion fn */ 290 291 int bip_error; /* saved I/O error */ 292 unsigned int bip_size; 293 294 unsigned short bip_pool; /* pool the ivec came from */ 295 unsigned short bip_vcnt; /* # of integrity bio_vecs */ 296 unsigned short bip_idx; /* current bip_vec index */ 297 298 struct work_struct bip_work; /* I/O completion */ 299 }; 300 #endif /* CONFIG_BLK_DEV_INTEGRITY */ 301 302 /* 303 * A bio_pair is used when we need to split a bio. 304 * This can only happen for a bio that refers to just one 305 * page of data, and in the unusual situation when the 306 * page crosses a chunk/device boundary 307 * 308 * The address of the master bio is stored in bio1.bi_private 309 * The address of the pool the pair was allocated from is stored 310 * in bio2.bi_private 311 */ 312 struct bio_pair { 313 struct bio bio1, bio2; 314 struct bio_vec bv1, bv2; 315 #if defined(CONFIG_BLK_DEV_INTEGRITY) 316 struct bio_integrity_payload bip1, bip2; 317 struct bio_vec iv1, iv2; 318 #endif 319 atomic_t cnt; 320 int error; 321 }; 322 extern struct bio_pair *bio_split(struct bio *bi, mempool_t *pool, 323 int first_sectors); 324 extern mempool_t *bio_split_pool; 325 extern void bio_pair_release(struct bio_pair *dbio); 326 327 extern struct bio_set *bioset_create(int, int); 328 extern void bioset_free(struct bio_set *); 329 330 extern struct bio *bio_alloc(gfp_t, int); 331 extern struct bio *bio_alloc_bioset(gfp_t, int, struct bio_set *); 332 extern void bio_put(struct bio *); 333 extern void bio_free(struct bio *, struct bio_set *); 334 335 extern void bio_endio(struct bio *, int); 336 struct request_queue; 337 extern int bio_phys_segments(struct request_queue *, struct bio *); 338 extern int bio_hw_segments(struct request_queue *, struct bio *); 339 340 extern void __bio_clone(struct bio *, struct bio *); 341 extern struct bio *bio_clone(struct bio *, gfp_t); 342 343 extern void bio_init(struct bio *); 344 345 extern int bio_add_page(struct bio *, struct page *, unsigned int,unsigned int); 346 extern int bio_add_pc_page(struct request_queue *, struct bio *, struct page *, 347 unsigned int, unsigned int); 348 extern int bio_get_nr_vecs(struct block_device *); 349 extern struct bio *bio_map_user(struct request_queue *, struct block_device *, 350 unsigned long, unsigned int, int); 351 struct sg_iovec; 352 extern struct bio *bio_map_user_iov(struct request_queue *, 353 struct block_device *, 354 struct sg_iovec *, int, int); 355 extern void bio_unmap_user(struct bio *); 356 extern struct bio *bio_map_kern(struct request_queue *, void *, unsigned int, 357 gfp_t); 358 extern struct bio *bio_copy_kern(struct request_queue *, void *, unsigned int, 359 gfp_t, int); 360 extern void bio_set_pages_dirty(struct bio *bio); 361 extern void bio_check_pages_dirty(struct bio *bio); 362 extern struct bio *bio_copy_user(struct request_queue *, unsigned long, unsigned int, int); 363 extern struct bio *bio_copy_user_iov(struct request_queue *, struct sg_iovec *, 364 int, int); 365 extern int bio_uncopy_user(struct bio *); 366 void zero_fill_bio(struct bio *bio); 367 extern struct bio_vec *bvec_alloc_bs(gfp_t, int, unsigned long *, struct bio_set *); 368 extern unsigned int bvec_nr_vecs(unsigned short idx); 369 370 /* 371 * bio_set is used to allow other portions of the IO system to 372 * allocate their own private memory pools for bio and iovec structures. 373 * These memory pools in turn all allocate from the bio_slab 374 * and the bvec_slabs[]. 375 */ 376 #define BIO_POOL_SIZE 2 377 #define BIOVEC_NR_POOLS 6 378 379 struct bio_set { 380 mempool_t *bio_pool; 381 #if defined(CONFIG_BLK_DEV_INTEGRITY) 382 mempool_t *bio_integrity_pool; 383 #endif 384 mempool_t *bvec_pools[BIOVEC_NR_POOLS]; 385 }; 386 387 struct biovec_slab { 388 int nr_vecs; 389 char *name; 390 struct kmem_cache *slab; 391 }; 392 393 extern struct bio_set *fs_bio_set; 394 395 /* 396 * a small number of entries is fine, not going to be performance critical. 397 * basically we just need to survive 398 */ 399 #define BIO_SPLIT_ENTRIES 2 400 401 #ifdef CONFIG_HIGHMEM 402 /* 403 * remember to add offset! and never ever reenable interrupts between a 404 * bvec_kmap_irq and bvec_kunmap_irq!! 405 * 406 * This function MUST be inlined - it plays with the CPU interrupt flags. 407 */ 408 static inline char *bvec_kmap_irq(struct bio_vec *bvec, unsigned long *flags) 409 { 410 unsigned long addr; 411 412 /* 413 * might not be a highmem page, but the preempt/irq count 414 * balancing is a lot nicer this way 415 */ 416 local_irq_save(*flags); 417 addr = (unsigned long) kmap_atomic(bvec->bv_page, KM_BIO_SRC_IRQ); 418 419 BUG_ON(addr & ~PAGE_MASK); 420 421 return (char *) addr + bvec->bv_offset; 422 } 423 424 static inline void bvec_kunmap_irq(char *buffer, unsigned long *flags) 425 { 426 unsigned long ptr = (unsigned long) buffer & PAGE_MASK; 427 428 kunmap_atomic((void *) ptr, KM_BIO_SRC_IRQ); 429 local_irq_restore(*flags); 430 } 431 432 #else 433 #define bvec_kmap_irq(bvec, flags) (page_address((bvec)->bv_page) + (bvec)->bv_offset) 434 #define bvec_kunmap_irq(buf, flags) do { *(flags) = 0; } while (0) 435 #endif 436 437 static inline char *__bio_kmap_irq(struct bio *bio, unsigned short idx, 438 unsigned long *flags) 439 { 440 return bvec_kmap_irq(bio_iovec_idx(bio, idx), flags); 441 } 442 #define __bio_kunmap_irq(buf, flags) bvec_kunmap_irq(buf, flags) 443 444 #define bio_kmap_irq(bio, flags) \ 445 __bio_kmap_irq((bio), (bio)->bi_idx, (flags)) 446 #define bio_kunmap_irq(buf,flags) __bio_kunmap_irq(buf, flags) 447 448 #if defined(CONFIG_BLK_DEV_INTEGRITY) 449 450 #define bip_vec_idx(bip, idx) (&(bip->bip_vec[(idx)])) 451 #define bip_vec(bip) bip_vec_idx(bip, 0) 452 453 #define __bip_for_each_vec(bvl, bip, i, start_idx) \ 454 for (bvl = bip_vec_idx((bip), (start_idx)), i = (start_idx); \ 455 i < (bip)->bip_vcnt; \ 456 bvl++, i++) 457 458 #define bip_for_each_vec(bvl, bip, i) \ 459 __bip_for_each_vec(bvl, bip, i, (bip)->bip_idx) 460 461 static inline int bio_integrity(struct bio *bio) 462 { 463 #if defined(CONFIG_BLK_DEV_INTEGRITY) 464 return bio->bi_integrity != NULL; 465 #else 466 return 0; 467 #endif 468 } 469 470 extern struct bio_integrity_payload *bio_integrity_alloc_bioset(struct bio *, gfp_t, unsigned int, struct bio_set *); 471 extern struct bio_integrity_payload *bio_integrity_alloc(struct bio *, gfp_t, unsigned int); 472 extern void bio_integrity_free(struct bio *, struct bio_set *); 473 extern int bio_integrity_add_page(struct bio *, struct page *, unsigned int, unsigned int); 474 extern int bio_integrity_enabled(struct bio *bio); 475 extern int bio_integrity_set_tag(struct bio *, void *, unsigned int); 476 extern int bio_integrity_get_tag(struct bio *, void *, unsigned int); 477 extern int bio_integrity_prep(struct bio *); 478 extern void bio_integrity_endio(struct bio *, int); 479 extern void bio_integrity_advance(struct bio *, unsigned int); 480 extern void bio_integrity_trim(struct bio *, unsigned int, unsigned int); 481 extern void bio_integrity_split(struct bio *, struct bio_pair *, int); 482 extern int bio_integrity_clone(struct bio *, struct bio *, struct bio_set *); 483 extern int bioset_integrity_create(struct bio_set *, int); 484 extern void bioset_integrity_free(struct bio_set *); 485 extern void bio_integrity_init_slab(void); 486 487 #else /* CONFIG_BLK_DEV_INTEGRITY */ 488 489 #define bio_integrity(a) (0) 490 #define bioset_integrity_create(a, b) (0) 491 #define bio_integrity_prep(a) (0) 492 #define bio_integrity_enabled(a) (0) 493 #define bio_integrity_clone(a, b, c) (0) 494 #define bioset_integrity_free(a) do { } while (0) 495 #define bio_integrity_free(a, b) do { } while (0) 496 #define bio_integrity_endio(a, b) do { } while (0) 497 #define bio_integrity_advance(a, b) do { } while (0) 498 #define bio_integrity_trim(a, b, c) do { } while (0) 499 #define bio_integrity_split(a, b, c) do { } while (0) 500 #define bio_integrity_set_tag(a, b, c) do { } while (0) 501 #define bio_integrity_get_tag(a, b, c) do { } while (0) 502 #define bio_integrity_init_slab(a) do { } while (0) 503 504 #endif /* CONFIG_BLK_DEV_INTEGRITY */ 505 506 #endif /* CONFIG_BLOCK */ 507 #endif /* __LINUX_BIO_H */ 508