1/* 2 * Copyright (C) 2001 Jens Axboe <axboe@kernel.dk> 3 * 4 * This program is free software; you can redistribute it and/or modify 5 * it under the terms of the GNU General Public License version 2 as 6 * published by the Free Software Foundation. 7 * 8 * This program is distributed in the hope that it will be useful, 9 * but WITHOUT ANY WARRANTY; without even the implied warranty of 10 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the 11 * GNU General Public License for more details. 12 * 13 * You should have received a copy of the GNU General Public Licens 14 * along with this program; if not, write to the Free Software 15 * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111- 16 * 17 */ 18#include <linux/mm.h> 19#include <linux/swap.h> 20#include <linux/bio.h> 21#include <linux/blkdev.h> 22#include <linux/slab.h> 23#include <linux/init.h> 24#include <linux/kernel.h> 25#include <linux/module.h> 26#include <linux/mempool.h> 27#include <linux/workqueue.h> 28#include <scsi/sg.h> /* for struct sg_iovec */ 29 30#include <trace/events/block.h> 31 32/* 33 * Test patch to inline a certain number of bi_io_vec's inside the bio 34 * itself, to shrink a bio data allocation from two mempool calls to one 35 */ 36#define BIO_INLINE_VECS 4 37 38static mempool_t *bio_split_pool __read_mostly; 39 40/* 41 * if you change this list, also change bvec_alloc or things will 42 * break badly! cannot be bigger than what you can fit into an 43 * unsigned short 44 */ 45#define BV(x) { .nr_vecs = x, .name = "biovec-"__stringify(x) } 46struct biovec_slab bvec_slabs[BIOVEC_NR_POOLS] __read_mostly = { 47 BV(1), BV(4), BV(16), BV(64), BV(128), BV(BIO_MAX_PAGES), 48}; 49#undef BV 50 51/* 52 * fs_bio_set is the bio_set containing bio and iovec memory pools used by 53 * IO code that does not need private memory pools. 54 */ 55struct bio_set *fs_bio_set; 56 57/* 58 * Our slab pool management 59 */ 60struct bio_slab { 61 struct kmem_cache *slab; 62 unsigned int slab_ref; 63 unsigned int slab_size; 64 char name[8]; 65}; 66static DEFINE_MUTEX(bio_slab_lock); 67static struct bio_slab *bio_slabs; 68static unsigned int bio_slab_nr, bio_slab_max; 69 70static struct kmem_cache *bio_find_or_create_slab(unsigned int extra_size) 71{ 72 unsigned int sz = sizeof(struct bio) + extra_size; 73 struct kmem_cache *slab = NULL; 74 struct bio_slab *bslab; 75 unsigned int i, entry = -1; 76 77 mutex_lock(&bio_slab_lock); 78 79 i = 0; 80 while (i < bio_slab_nr) { 81 bslab = &bio_slabs[i]; 82 83 if (!bslab->slab && entry == -1) 84 entry = i; 85 else if (bslab->slab_size == sz) { 86 slab = bslab->slab; 87 bslab->slab_ref++; 88 break; 89 } 90 i++; 91 } 92 93 if (slab) 94 goto out_unlock; 95 96 if (bio_slab_nr == bio_slab_max && entry == -1) { 97 bio_slab_max <<= 1; 98 bio_slabs = krealloc(bio_slabs, 99 bio_slab_max * sizeof(struct bio_slab), 100 GFP_KERNEL); 101 if (!bio_slabs) 102 goto out_unlock; 103 } 104 if (entry == -1) 105 entry = bio_slab_nr++; 106 107 bslab = &bio_slabs[entry]; 108 109 snprintf(bslab->name, sizeof(bslab->name), "bio-%d", entry); 110 slab = kmem_cache_create(bslab->name, sz, 0, SLAB_HWCACHE_ALIGN, NULL); 111 if (!slab) 112 goto out_unlock; 113 114 printk("bio: create slab <%s> at %d\n", bslab->name, entry); 115 bslab->slab = slab; 116 bslab->slab_ref = 1; 117 bslab->slab_size = sz; 118out_unlock: 119 mutex_unlock(&bio_slab_lock); 120 return slab; 121} 122 123static void bio_put_slab(struct bio_set *bs) 124{ 125 struct bio_slab *bslab = NULL; 126 unsigned int i; 127 128 mutex_lock(&bio_slab_lock); 129 130 for (i = 0; i < bio_slab_nr; i++) { 131 if (bs->bio_slab == bio_slabs[i].slab) { 132 bslab = &bio_slabs[i]; 133 break; 134 } 135 } 136 137 if (WARN(!bslab, KERN_ERR "bio: unable to find slab!\n")) 138 goto out; 139 140 WARN_ON(!bslab->slab_ref); 141 142 if (--bslab->slab_ref) 143 goto out; 144 145 kmem_cache_destroy(bslab->slab); 146 bslab->slab = NULL; 147 148out: 149 mutex_unlock(&bio_slab_lock); 150} 151 152unsigned int bvec_nr_vecs(unsigned short idx) 153{ 154 return bvec_slabs[idx].nr_vecs; 155} 156 157void bvec_free_bs(struct bio_set *bs, struct bio_vec *bv, unsigned int idx) 158{ 159 BIO_BUG_ON(idx >= BIOVEC_NR_POOLS); 160 161 if (idx == BIOVEC_MAX_IDX) 162 mempool_free(bv, bs->bvec_pool); 163 else { 164 struct biovec_slab *bvs = bvec_slabs + idx; 165 166 kmem_cache_free(bvs->slab, bv); 167 } 168} 169 170struct bio_vec *bvec_alloc_bs(gfp_t gfp_mask, int nr, unsigned long *idx, 171 struct bio_set *bs) 172{ 173 struct bio_vec *bvl; 174 175 /* 176 * see comment near bvec_array define! 177 */ 178 switch (nr) { 179 case 1: 180 *idx = 0; 181 break; 182 case 2 ... 4: 183 *idx = 1; 184 break; 185 case 5 ... 16: 186 *idx = 2; 187 break; 188 case 17 ... 64: 189 *idx = 3; 190 break; 191 case 65 ... 128: 192 *idx = 4; 193 break; 194 case 129 ... BIO_MAX_PAGES: 195 *idx = 5; 196 break; 197 default: 198 return NULL; 199 } 200 201 /* 202 * idx now points to the pool we want to allocate from. only the 203 * 1-vec entry pool is mempool backed. 204 */ 205 if (*idx == BIOVEC_MAX_IDX) { 206fallback: 207 bvl = mempool_alloc(bs->bvec_pool, gfp_mask); 208 } else { 209 struct biovec_slab *bvs = bvec_slabs + *idx; 210 gfp_t __gfp_mask = gfp_mask & ~(__GFP_WAIT | __GFP_IO); 211 212 /* 213 * Make this allocation restricted and don't dump info on 214 * allocation failures, since we'll fallback to the mempool 215 * in case of failure. 216 */ 217 __gfp_mask |= __GFP_NOMEMALLOC | __GFP_NORETRY | __GFP_NOWARN; 218 219 /* 220 * Try a slab allocation. If this fails and __GFP_WAIT 221 * is set, retry with the 1-entry mempool 222 */ 223 bvl = kmem_cache_alloc(bvs->slab, __gfp_mask); 224 if (unlikely(!bvl && (gfp_mask & __GFP_WAIT))) { 225 *idx = BIOVEC_MAX_IDX; 226 goto fallback; 227 } 228 } 229 230 return bvl; 231} 232 233void bio_free(struct bio *bio, struct bio_set *bs) 234{ 235 void *p; 236 237 if (bio_has_allocated_vec(bio)) 238 bvec_free_bs(bs, bio->bi_io_vec, BIO_POOL_IDX(bio)); 239 240 if (bio_integrity(bio)) 241 bio_integrity_free(bio, bs); 242 243 /* 244 * If we have front padding, adjust the bio pointer before freeing 245 */ 246 p = bio; 247 if (bs->front_pad) 248 p -= bs->front_pad; 249 250 mempool_free(p, bs->bio_pool); 251} 252EXPORT_SYMBOL(bio_free); 253 254void bio_init(struct bio *bio) 255{ 256 memset(bio, 0, sizeof(*bio)); 257 bio->bi_flags = 1 << BIO_UPTODATE; 258 bio->bi_comp_cpu = -1; 259 atomic_set(&bio->bi_cnt, 1); 260} 261EXPORT_SYMBOL(bio_init); 262 263/** 264 * bio_alloc_bioset - allocate a bio for I/O 265 * @gfp_mask: the GFP_ mask given to the slab allocator 266 * @nr_iovecs: number of iovecs to pre-allocate 267 * @bs: the bio_set to allocate from. 268 * 269 * Description: 270 * bio_alloc_bioset will try its own mempool to satisfy the allocation. 271 * If %__GFP_WAIT is set then we will block on the internal pool waiting 272 * for a &struct bio to become free. 273 * 274 * Note that the caller must set ->bi_destructor on successful return 275 * of a bio, to do the appropriate freeing of the bio once the reference 276 * count drops to zero. 277 **/ 278struct bio *bio_alloc_bioset(gfp_t gfp_mask, int nr_iovecs, struct bio_set *bs) 279{ 280 unsigned long idx = BIO_POOL_NONE; 281 struct bio_vec *bvl = NULL; 282 struct bio *bio; 283 void *p; 284 285 p = mempool_alloc(bs->bio_pool, gfp_mask); 286 if (unlikely(!p)) 287 return NULL; 288 bio = p + bs->front_pad; 289 290 bio_init(bio); 291 292 if (unlikely(!nr_iovecs)) 293 goto out_set; 294 295 if (nr_iovecs <= BIO_INLINE_VECS) { 296 bvl = bio->bi_inline_vecs; 297 nr_iovecs = BIO_INLINE_VECS; 298 } else { 299 bvl = bvec_alloc_bs(gfp_mask, nr_iovecs, &idx, bs); 300 if (unlikely(!bvl)) 301 goto err_free; 302 303 nr_iovecs = bvec_nr_vecs(idx); 304 } 305out_set: 306 bio->bi_flags |= idx << BIO_POOL_OFFSET; 307 bio->bi_max_vecs = nr_iovecs; 308 bio->bi_io_vec = bvl; 309 return bio; 310 311err_free: 312 mempool_free(p, bs->bio_pool); 313 return NULL; 314} 315EXPORT_SYMBOL(bio_alloc_bioset); 316 317static void bio_fs_destructor(struct bio *bio) 318{ 319 bio_free(bio, fs_bio_set); 320} 321 322/** 323 * bio_alloc - allocate a new bio, memory pool backed 324 * @gfp_mask: allocation mask to use 325 * @nr_iovecs: number of iovecs 326 * 327 * bio_alloc will allocate a bio and associated bio_vec array that can hold 328 * at least @nr_iovecs entries. Allocations will be done from the 329 * fs_bio_set. Also see @bio_alloc_bioset and @bio_kmalloc. 330 * 331 * If %__GFP_WAIT is set, then bio_alloc will always be able to allocate 332 * a bio. This is due to the mempool guarantees. To make this work, callers 333 * must never allocate more than 1 bio at a time from this pool. Callers 334 * that need to allocate more than 1 bio must always submit the previously 335 * allocated bio for IO before attempting to allocate a new one. Failure to 336 * do so can cause livelocks under memory pressure. 337 * 338 * RETURNS: 339 * Pointer to new bio on success, NULL on failure. 340 */ 341struct bio *bio_alloc(gfp_t gfp_mask, int nr_iovecs) 342{ 343 struct bio *bio = bio_alloc_bioset(gfp_mask, nr_iovecs, fs_bio_set); 344 345 if (bio) 346 bio->bi_destructor = bio_fs_destructor; 347 348 return bio; 349} 350EXPORT_SYMBOL(bio_alloc); 351 352static void bio_kmalloc_destructor(struct bio *bio) 353{ 354 if (bio_integrity(bio)) 355 bio_integrity_free(bio, fs_bio_set); 356 kfree(bio); 357} 358 359/** 360 * bio_kmalloc - allocate a bio for I/O using kmalloc() 361 * @gfp_mask: the GFP_ mask given to the slab allocator 362 * @nr_iovecs: number of iovecs to pre-allocate 363 * 364 * Description: 365 * Allocate a new bio with @nr_iovecs bvecs. If @gfp_mask contains 366 * %__GFP_WAIT, the allocation is guaranteed to succeed. 367 * 368 **/ 369struct bio *bio_kmalloc(gfp_t gfp_mask, int nr_iovecs) 370{ 371 struct bio *bio; 372 373 if (nr_iovecs > UIO_MAXIOV) 374 return NULL; 375 376 bio = kmalloc(sizeof(struct bio) + nr_iovecs * sizeof(struct bio_vec), 377 gfp_mask); 378 if (unlikely(!bio)) 379 return NULL; 380 381 bio_init(bio); 382 bio->bi_flags |= BIO_POOL_NONE << BIO_POOL_OFFSET; 383 bio->bi_max_vecs = nr_iovecs; 384 bio->bi_io_vec = bio->bi_inline_vecs; 385 bio->bi_destructor = bio_kmalloc_destructor; 386 387 return bio; 388} 389EXPORT_SYMBOL(bio_kmalloc); 390 391void zero_fill_bio(struct bio *bio) 392{ 393 unsigned long flags; 394 struct bio_vec *bv; 395 int i; 396 397 bio_for_each_segment(bv, bio, i) { 398 char *data = bvec_kmap_irq(bv, &flags); 399 memset(data, 0, bv->bv_len); 400 flush_dcache_page(bv->bv_page); 401 bvec_kunmap_irq(data, &flags); 402 } 403} 404EXPORT_SYMBOL(zero_fill_bio); 405 406/** 407 * bio_put - release a reference to a bio 408 * @bio: bio to release reference to 409 * 410 * Description: 411 * Put a reference to a &struct bio, either one you have gotten with 412 * bio_alloc, bio_get or bio_clone. The last put of a bio will free it. 413 **/ 414void bio_put(struct bio *bio) 415{ 416 BIO_BUG_ON(!atomic_read(&bio->bi_cnt)); 417 418 /* 419 * last put frees it 420 */ 421 if (atomic_dec_and_test(&bio->bi_cnt)) { 422 bio->bi_next = NULL; 423 bio->bi_destructor(bio); 424 } 425} 426EXPORT_SYMBOL(bio_put); 427 428inline int bio_phys_segments(struct request_queue *q, struct bio *bio) 429{ 430 if (unlikely(!bio_flagged(bio, BIO_SEG_VALID))) 431 blk_recount_segments(q, bio); 432 433 return bio->bi_phys_segments; 434} 435EXPORT_SYMBOL(bio_phys_segments); 436 437/** 438 * __bio_clone - clone a bio 439 * @bio: destination bio 440 * @bio_src: bio to clone 441 * 442 * Clone a &bio. Caller will own the returned bio, but not 443 * the actual data it points to. Reference count of returned 444 * bio will be one. 445 */ 446void __bio_clone(struct bio *bio, struct bio *bio_src) 447{ 448 memcpy(bio->bi_io_vec, bio_src->bi_io_vec, 449 bio_src->bi_max_vecs * sizeof(struct bio_vec)); 450 451 /* 452 * most users will be overriding ->bi_bdev with a new target, 453 * so we don't set nor calculate new physical/hw segment counts here 454 */ 455 bio->bi_sector = bio_src->bi_sector; 456 bio->bi_bdev = bio_src->bi_bdev; 457 bio->bi_flags |= 1 << BIO_CLONED; 458 bio->bi_rw = bio_src->bi_rw; 459 bio->bi_vcnt = bio_src->bi_vcnt; 460 bio->bi_size = bio_src->bi_size; 461 bio->bi_idx = bio_src->bi_idx; 462} 463EXPORT_SYMBOL(__bio_clone); 464 465/** 466 * bio_clone - clone a bio 467 * @bio: bio to clone 468 * @gfp_mask: allocation priority 469 * 470 * Like __bio_clone, only also allocates the returned bio 471 */ 472struct bio *bio_clone(struct bio *bio, gfp_t gfp_mask) 473{ 474 struct bio *b = bio_alloc_bioset(gfp_mask, bio->bi_max_vecs, fs_bio_set); 475 476 if (!b) 477 return NULL; 478 479 b->bi_destructor = bio_fs_destructor; 480 __bio_clone(b, bio); 481 482 if (bio_integrity(bio)) { 483 int ret; 484 485 ret = bio_integrity_clone(b, bio, gfp_mask, fs_bio_set); 486 487 if (ret < 0) { 488 bio_put(b); 489 return NULL; 490 } 491 } 492 493 return b; 494} 495EXPORT_SYMBOL(bio_clone); 496 497/** 498 * bio_get_nr_vecs - return approx number of vecs 499 * @bdev: I/O target 500 * 501 * Return the approximate number of pages we can send to this target. 502 * There's no guarantee that you will be able to fit this number of pages 503 * into a bio, it does not account for dynamic restrictions that vary 504 * on offset. 505 */ 506int bio_get_nr_vecs(struct block_device *bdev) 507{ 508 struct request_queue *q = bdev_get_queue(bdev); 509 int nr_pages; 510 511 nr_pages = ((queue_max_sectors(q) << 9) + PAGE_SIZE - 1) >> PAGE_SHIFT; 512 if (nr_pages > queue_max_segments(q)) 513 nr_pages = queue_max_segments(q); 514 515 return nr_pages; 516} 517EXPORT_SYMBOL(bio_get_nr_vecs); 518 519static int __bio_add_page(struct request_queue *q, struct bio *bio, struct page 520 *page, unsigned int len, unsigned int offset, 521 unsigned short max_sectors) 522{ 523 int retried_segments = 0; 524 struct bio_vec *bvec; 525 526 /* 527 * cloned bio must not modify vec list 528 */ 529 if (unlikely(bio_flagged(bio, BIO_CLONED))) 530 return 0; 531 532 if (((bio->bi_size + len) >> 9) > max_sectors) 533 return 0; 534 535 /* 536 * For filesystems with a blocksize smaller than the pagesize 537 * we will often be called with the same page as last time and 538 * a consecutive offset. Optimize this special case. 539 */ 540 if (bio->bi_vcnt > 0) { 541 struct bio_vec *prev = &bio->bi_io_vec[bio->bi_vcnt - 1]; 542 543 if (page == prev->bv_page && 544 offset == prev->bv_offset + prev->bv_len) { 545 unsigned int prev_bv_len = prev->bv_len; 546 prev->bv_len += len; 547 548 if (q->merge_bvec_fn) { 549 struct bvec_merge_data bvm = { 550 /* prev_bvec is already charged in 551 bi_size, discharge it in order to 552 simulate merging updated prev_bvec 553 as new bvec. */ 554 .bi_bdev = bio->bi_bdev, 555 .bi_sector = bio->bi_sector, 556 .bi_size = bio->bi_size - prev_bv_len, 557 .bi_rw = bio->bi_rw, 558 }; 559 560 if (q->merge_bvec_fn(q, &bvm, prev) < prev->bv_len) { 561 prev->bv_len -= len; 562 return 0; 563 } 564 } 565 566 goto done; 567 } 568 } 569 570 if (bio->bi_vcnt >= bio->bi_max_vecs) 571 return 0; 572 573 /* 574 * we might lose a segment or two here, but rather that than 575 * make this too complex. 576 */ 577 578 while (bio->bi_phys_segments >= queue_max_segments(q)) { 579 580 if (retried_segments) 581 return 0; 582 583 retried_segments = 1; 584 blk_recount_segments(q, bio); 585 } 586 587 /* 588 * setup the new entry, we might clear it again later if we 589 * cannot add the page 590 */ 591 bvec = &bio->bi_io_vec[bio->bi_vcnt]; 592 bvec->bv_page = page; 593 bvec->bv_len = len; 594 bvec->bv_offset = offset; 595 596 /* 597 * if queue has other restrictions (eg varying max sector size 598 * depending on offset), it can specify a merge_bvec_fn in the 599 * queue to get further control 600 */ 601 if (q->merge_bvec_fn) { 602 struct bvec_merge_data bvm = { 603 .bi_bdev = bio->bi_bdev, 604 .bi_sector = bio->bi_sector, 605 .bi_size = bio->bi_size, 606 .bi_rw = bio->bi_rw, 607 }; 608 609 /* 610 * merge_bvec_fn() returns number of bytes it can accept 611 * at this offset 612 */ 613 if (q->merge_bvec_fn(q, &bvm, bvec) < bvec->bv_len) { 614 bvec->bv_page = NULL; 615 bvec->bv_len = 0; 616 bvec->bv_offset = 0; 617 return 0; 618 } 619 } 620 621 /* If we may be able to merge these biovecs, force a recount */ 622 if (bio->bi_vcnt && (BIOVEC_PHYS_MERGEABLE(bvec-1, bvec))) 623 bio->bi_flags &= ~(1 << BIO_SEG_VALID); 624 625 bio->bi_vcnt++; 626 bio->bi_phys_segments++; 627 done: 628 bio->bi_size += len; 629 return len; 630} 631 632/** 633 * bio_add_pc_page - attempt to add page to bio 634 * @q: the target queue 635 * @bio: destination bio 636 * @page: page to add 637 * @len: vec entry length 638 * @offset: vec entry offset 639 * 640 * Attempt to add a page to the bio_vec maplist. This can fail for a 641 * number of reasons, such as the bio being full or target block 642 * device limitations. The target block device must allow bio's 643 * smaller than PAGE_SIZE, so it is always possible to add a single 644 * page to an empty bio. This should only be used by REQ_PC bios. 645 */ 646int bio_add_pc_page(struct request_queue *q, struct bio *bio, struct page *page, 647 unsigned int len, unsigned int offset) 648{ 649 return __bio_add_page(q, bio, page, len, offset, 650 queue_max_hw_sectors(q)); 651} 652EXPORT_SYMBOL(bio_add_pc_page); 653 654/** 655 * bio_add_page - attempt to add page to bio 656 * @bio: destination bio 657 * @page: page to add 658 * @len: vec entry length 659 * @offset: vec entry offset 660 * 661 * Attempt to add a page to the bio_vec maplist. This can fail for a 662 * number of reasons, such as the bio being full or target block 663 * device limitations. The target block device must allow bio's 664 * smaller than PAGE_SIZE, so it is always possible to add a single 665 * page to an empty bio. 666 */ 667int bio_add_page(struct bio *bio, struct page *page, unsigned int len, 668 unsigned int offset) 669{ 670 struct request_queue *q = bdev_get_queue(bio->bi_bdev); 671 return __bio_add_page(q, bio, page, len, offset, queue_max_sectors(q)); 672} 673EXPORT_SYMBOL(bio_add_page); 674 675struct bio_map_data { 676 struct bio_vec *iovecs; 677 struct sg_iovec *sgvecs; 678 int nr_sgvecs; 679 int is_our_pages; 680}; 681 682static void bio_set_map_data(struct bio_map_data *bmd, struct bio *bio, 683 struct sg_iovec *iov, int iov_count, 684 int is_our_pages) 685{ 686 memcpy(bmd->iovecs, bio->bi_io_vec, sizeof(struct bio_vec) * bio->bi_vcnt); 687 memcpy(bmd->sgvecs, iov, sizeof(struct sg_iovec) * iov_count); 688 bmd->nr_sgvecs = iov_count; 689 bmd->is_our_pages = is_our_pages; 690 bio->bi_private = bmd; 691} 692 693static void bio_free_map_data(struct bio_map_data *bmd) 694{ 695 kfree(bmd->iovecs); 696 kfree(bmd->sgvecs); 697 kfree(bmd); 698} 699 700static struct bio_map_data *bio_alloc_map_data(int nr_segs, int iov_count, 701 gfp_t gfp_mask) 702{ 703 struct bio_map_data *bmd; 704 705 if (iov_count > UIO_MAXIOV) 706 return NULL; 707 708 bmd = kmalloc(sizeof(*bmd), gfp_mask); 709 if (!bmd) 710 return NULL; 711 712 bmd->iovecs = kmalloc(sizeof(struct bio_vec) * nr_segs, gfp_mask); 713 if (!bmd->iovecs) { 714 kfree(bmd); 715 return NULL; 716 } 717 718 bmd->sgvecs = kmalloc(sizeof(struct sg_iovec) * iov_count, gfp_mask); 719 if (bmd->sgvecs) 720 return bmd; 721 722 kfree(bmd->iovecs); 723 kfree(bmd); 724 return NULL; 725} 726 727static int __bio_copy_iov(struct bio *bio, struct bio_vec *iovecs, 728 struct sg_iovec *iov, int iov_count, 729 int to_user, int from_user, int do_free_page) 730{ 731 int ret = 0, i; 732 struct bio_vec *bvec; 733 int iov_idx = 0; 734 unsigned int iov_off = 0; 735 736 __bio_for_each_segment(bvec, bio, i, 0) { 737 char *bv_addr = page_address(bvec->bv_page); 738 unsigned int bv_len = iovecs[i].bv_len; 739 740 while (bv_len && iov_idx < iov_count) { 741 unsigned int bytes; 742 char __user *iov_addr; 743 744 bytes = min_t(unsigned int, 745 iov[iov_idx].iov_len - iov_off, bv_len); 746 iov_addr = iov[iov_idx].iov_base + iov_off; 747 748 if (!ret) { 749 if (to_user) 750 ret = copy_to_user(iov_addr, bv_addr, 751 bytes); 752 753 if (from_user) 754 ret = copy_from_user(bv_addr, iov_addr, 755 bytes); 756 757 if (ret) 758 ret = -EFAULT; 759 } 760 761 bv_len -= bytes; 762 bv_addr += bytes; 763 iov_addr += bytes; 764 iov_off += bytes; 765 766 if (iov[iov_idx].iov_len == iov_off) { 767 iov_idx++; 768 iov_off = 0; 769 } 770 } 771 772 if (do_free_page) 773 __free_page(bvec->bv_page); 774 } 775 776 return ret; 777} 778 779/** 780 * bio_uncopy_user - finish previously mapped bio 781 * @bio: bio being terminated 782 * 783 * Free pages allocated from bio_copy_user() and write back data 784 * to user space in case of a read. 785 */ 786int bio_uncopy_user(struct bio *bio) 787{ 788 struct bio_map_data *bmd = bio->bi_private; 789 int ret = 0; 790 791 if (!bio_flagged(bio, BIO_NULL_MAPPED)) 792 ret = __bio_copy_iov(bio, bmd->iovecs, bmd->sgvecs, 793 bmd->nr_sgvecs, bio_data_dir(bio) == READ, 794 0, bmd->is_our_pages); 795 bio_free_map_data(bmd); 796 bio_put(bio); 797 return ret; 798} 799EXPORT_SYMBOL(bio_uncopy_user); 800 801/** 802 * bio_copy_user_iov - copy user data to bio 803 * @q: destination block queue 804 * @map_data: pointer to the rq_map_data holding pages (if necessary) 805 * @iov: the iovec. 806 * @iov_count: number of elements in the iovec 807 * @write_to_vm: bool indicating writing to pages or not 808 * @gfp_mask: memory allocation flags 809 * 810 * Prepares and returns a bio for indirect user io, bouncing data 811 * to/from kernel pages as necessary. Must be paired with 812 * call bio_uncopy_user() on io completion. 813 */ 814struct bio *bio_copy_user_iov(struct request_queue *q, 815 struct rq_map_data *map_data, 816 struct sg_iovec *iov, int iov_count, 817 int write_to_vm, gfp_t gfp_mask) 818{ 819 struct bio_map_data *bmd; 820 struct bio_vec *bvec; 821 struct page *page; 822 struct bio *bio; 823 int i, ret; 824 int nr_pages = 0; 825 unsigned int len = 0; 826 unsigned int offset = map_data ? map_data->offset & ~PAGE_MASK : 0; 827 828 for (i = 0; i < iov_count; i++) { 829 unsigned long uaddr; 830 unsigned long end; 831 unsigned long start; 832 833 uaddr = (unsigned long)iov[i].iov_base; 834 end = (uaddr + iov[i].iov_len + PAGE_SIZE - 1) >> PAGE_SHIFT; 835 start = uaddr >> PAGE_SHIFT; 836 837 /* 838 * Overflow, abort 839 */ 840 if (end < start) 841 return ERR_PTR(-EINVAL); 842 843 nr_pages += end - start; 844 len += iov[i].iov_len; 845 } 846 847 if (offset) 848 nr_pages++; 849 850 bmd = bio_alloc_map_data(nr_pages, iov_count, gfp_mask); 851 if (!bmd) 852 return ERR_PTR(-ENOMEM); 853 854 ret = -ENOMEM; 855 bio = bio_kmalloc(gfp_mask, nr_pages); 856 if (!bio) 857 goto out_bmd; 858 859 if (!write_to_vm) 860 bio->bi_rw |= REQ_WRITE; 861 862 ret = 0; 863 864 if (map_data) { 865 nr_pages = 1 << map_data->page_order; 866 i = map_data->offset / PAGE_SIZE; 867 } 868 while (len) { 869 unsigned int bytes = PAGE_SIZE; 870 871 bytes -= offset; 872 873 if (bytes > len) 874 bytes = len; 875 876 if (map_data) { 877 if (i == map_data->nr_entries * nr_pages) { 878 ret = -ENOMEM; 879 break; 880 } 881 882 page = map_data->pages[i / nr_pages]; 883 page += (i % nr_pages); 884 885 i++; 886 } else { 887 page = alloc_page(q->bounce_gfp | gfp_mask); 888 if (!page) { 889 ret = -ENOMEM; 890 break; 891 } 892 } 893 894 if (bio_add_pc_page(q, bio, page, bytes, offset) < bytes) 895 break; 896 897 len -= bytes; 898 offset = 0; 899 } 900 901 if (ret) 902 goto cleanup; 903 904 /* 905 * success 906 */ 907 if ((!write_to_vm && (!map_data || !map_data->null_mapped)) || 908 (map_data && map_data->from_user)) { 909 ret = __bio_copy_iov(bio, bio->bi_io_vec, iov, iov_count, 0, 1, 0); 910 if (ret) 911 goto cleanup; 912 } 913 914 bio_set_map_data(bmd, bio, iov, iov_count, map_data ? 0 : 1); 915 return bio; 916cleanup: 917 if (!map_data) 918 bio_for_each_segment(bvec, bio, i) 919 __free_page(bvec->bv_page); 920 921 bio_put(bio); 922out_bmd: 923 bio_free_map_data(bmd); 924 return ERR_PTR(ret); 925} 926 927/** 928 * bio_copy_user - copy user data to bio 929 * @q: destination block queue 930 * @map_data: pointer to the rq_map_data holding pages (if necessary) 931 * @uaddr: start of user address 932 * @len: length in bytes 933 * @write_to_vm: bool indicating writing to pages or not 934 * @gfp_mask: memory allocation flags 935 * 936 * Prepares and returns a bio for indirect user io, bouncing data 937 * to/from kernel pages as necessary. Must be paired with 938 * call bio_uncopy_user() on io completion. 939 */ 940struct bio *bio_copy_user(struct request_queue *q, struct rq_map_data *map_data, 941 unsigned long uaddr, unsigned int len, 942 int write_to_vm, gfp_t gfp_mask) 943{ 944 struct sg_iovec iov; 945 946 iov.iov_base = (void __user *)uaddr; 947 iov.iov_len = len; 948 949 return bio_copy_user_iov(q, map_data, &iov, 1, write_to_vm, gfp_mask); 950} 951EXPORT_SYMBOL(bio_copy_user); 952 953static struct bio *__bio_map_user_iov(struct request_queue *q, 954 struct block_device *bdev, 955 struct sg_iovec *iov, int iov_count, 956 int write_to_vm, gfp_t gfp_mask) 957{ 958 int i, j; 959 int nr_pages = 0; 960 struct page **pages; 961 struct bio *bio; 962 int cur_page = 0; 963 int ret, offset; 964 965 for (i = 0; i < iov_count; i++) { 966 unsigned long uaddr = (unsigned long)iov[i].iov_base; 967 unsigned long len = iov[i].iov_len; 968 unsigned long end = (uaddr + len + PAGE_SIZE - 1) >> PAGE_SHIFT; 969 unsigned long start = uaddr >> PAGE_SHIFT; 970 971 /* 972 * Overflow, abort 973 */ 974 if (end < start) 975 return ERR_PTR(-EINVAL); 976 977 nr_pages += end - start; 978 /* 979 * buffer must be aligned to at least hardsector size for now 980 */ 981 if (uaddr & queue_dma_alignment(q)) 982 return ERR_PTR(-EINVAL); 983 } 984 985 if (!nr_pages) 986 return ERR_PTR(-EINVAL); 987 988 bio = bio_kmalloc(gfp_mask, nr_pages); 989 if (!bio) 990 return ERR_PTR(-ENOMEM); 991 992 ret = -ENOMEM; 993 pages = kcalloc(nr_pages, sizeof(struct page *), gfp_mask); 994 if (!pages) 995 goto out; 996 997 for (i = 0; i < iov_count; i++) { 998 unsigned long uaddr = (unsigned long)iov[i].iov_base; 999 unsigned long len = iov[i].iov_len; 1000 unsigned long end = (uaddr + len + PAGE_SIZE - 1) >> PAGE_SHIFT; 1001 unsigned long start = uaddr >> PAGE_SHIFT; 1002 const int local_nr_pages = end - start; 1003 const int page_limit = cur_page + local_nr_pages; 1004 1005 ret = get_user_pages_fast(uaddr, local_nr_pages, 1006 write_to_vm, &pages[cur_page]); 1007 if (ret < local_nr_pages) { 1008 ret = -EFAULT; 1009 goto out_unmap; 1010 } 1011 1012 offset = uaddr & ~PAGE_MASK; 1013 for (j = cur_page; j < page_limit; j++) { 1014 unsigned int bytes = PAGE_SIZE - offset; 1015 1016 if (len <= 0) 1017 break; 1018 1019 if (bytes > len) 1020 bytes = len; 1021 1022 /* 1023 * sorry... 1024 */ 1025 if (bio_add_pc_page(q, bio, pages[j], bytes, offset) < 1026 bytes) 1027 break; 1028 1029 len -= bytes; 1030 offset = 0; 1031 } 1032 1033 cur_page = j; 1034 /* 1035 * release the pages we didn't map into the bio, if any 1036 */ 1037 while (j < page_limit) 1038 page_cache_release(pages[j++]); 1039 } 1040 1041 kfree(pages); 1042 1043 /* 1044 * set data direction, and check if mapped pages need bouncing 1045 */ 1046 if (!write_to_vm) 1047 bio->bi_rw |= REQ_WRITE; 1048 1049 bio->bi_bdev = bdev; 1050 bio->bi_flags |= (1 << BIO_USER_MAPPED); 1051 return bio; 1052 1053 out_unmap: 1054 for (i = 0; i < nr_pages; i++) { 1055 if(!pages[i]) 1056 break; 1057 page_cache_release(pages[i]); 1058 } 1059 out: 1060 kfree(pages); 1061 bio_put(bio); 1062 return ERR_PTR(ret); 1063} 1064 1065/** 1066 * bio_map_user - map user address into bio 1067 * @q: the struct request_queue for the bio 1068 * @bdev: destination block device 1069 * @uaddr: start of user address 1070 * @len: length in bytes 1071 * @write_to_vm: bool indicating writing to pages or not 1072 * @gfp_mask: memory allocation flags 1073 * 1074 * Map the user space address into a bio suitable for io to a block 1075 * device. Returns an error pointer in case of error. 1076 */ 1077struct bio *bio_map_user(struct request_queue *q, struct block_device *bdev, 1078 unsigned long uaddr, unsigned int len, int write_to_vm, 1079 gfp_t gfp_mask) 1080{ 1081 struct sg_iovec iov; 1082 1083 iov.iov_base = (void __user *)uaddr; 1084 iov.iov_len = len; 1085 1086 return bio_map_user_iov(q, bdev, &iov, 1, write_to_vm, gfp_mask); 1087} 1088EXPORT_SYMBOL(bio_map_user); 1089 1090/** 1091 * bio_map_user_iov - map user sg_iovec table into bio 1092 * @q: the struct request_queue for the bio 1093 * @bdev: destination block device 1094 * @iov: the iovec. 1095 * @iov_count: number of elements in the iovec 1096 * @write_to_vm: bool indicating writing to pages or not 1097 * @gfp_mask: memory allocation flags 1098 * 1099 * Map the user space address into a bio suitable for io to a block 1100 * device. Returns an error pointer in case of error. 1101 */ 1102struct bio *bio_map_user_iov(struct request_queue *q, struct block_device *bdev, 1103 struct sg_iovec *iov, int iov_count, 1104 int write_to_vm, gfp_t gfp_mask) 1105{ 1106 struct bio *bio; 1107 1108 bio = __bio_map_user_iov(q, bdev, iov, iov_count, write_to_vm, 1109 gfp_mask); 1110 if (IS_ERR(bio)) 1111 return bio; 1112 1113 /* 1114 * subtle -- if __bio_map_user() ended up bouncing a bio, 1115 * it would normally disappear when its bi_end_io is run. 1116 * however, we need it for the unmap, so grab an extra 1117 * reference to it 1118 */ 1119 bio_get(bio); 1120 1121 return bio; 1122} 1123 1124static void __bio_unmap_user(struct bio *bio) 1125{ 1126 struct bio_vec *bvec; 1127 int i; 1128 1129 /* 1130 * make sure we dirty pages we wrote to 1131 */ 1132 __bio_for_each_segment(bvec, bio, i, 0) { 1133 if (bio_data_dir(bio) == READ) 1134 set_page_dirty_lock(bvec->bv_page); 1135 1136 page_cache_release(bvec->bv_page); 1137 } 1138 1139 bio_put(bio); 1140} 1141 1142/** 1143 * bio_unmap_user - unmap a bio 1144 * @bio: the bio being unmapped 1145 * 1146 * Unmap a bio previously mapped by bio_map_user(). Must be called with 1147 * a process context. 1148 * 1149 * bio_unmap_user() may sleep. 1150 */ 1151void bio_unmap_user(struct bio *bio) 1152{ 1153 __bio_unmap_user(bio); 1154 bio_put(bio); 1155} 1156EXPORT_SYMBOL(bio_unmap_user); 1157 1158static void bio_map_kern_endio(struct bio *bio, int err) 1159{ 1160 bio_put(bio); 1161} 1162 1163static struct bio *__bio_map_kern(struct request_queue *q, void *data, 1164 unsigned int len, gfp_t gfp_mask) 1165{ 1166 unsigned long kaddr = (unsigned long)data; 1167 unsigned long end = (kaddr + len + PAGE_SIZE - 1) >> PAGE_SHIFT; 1168 unsigned long start = kaddr >> PAGE_SHIFT; 1169 const int nr_pages = end - start; 1170 int offset, i; 1171 struct bio *bio; 1172 1173 bio = bio_kmalloc(gfp_mask, nr_pages); 1174 if (!bio) 1175 return ERR_PTR(-ENOMEM); 1176 1177 offset = offset_in_page(kaddr); 1178 for (i = 0; i < nr_pages; i++) { 1179 unsigned int bytes = PAGE_SIZE - offset; 1180 1181 if (len <= 0) 1182 break; 1183 1184 if (bytes > len) 1185 bytes = len; 1186 1187 if (bio_add_pc_page(q, bio, virt_to_page(data), bytes, 1188 offset) < bytes) 1189 break; 1190 1191 data += bytes; 1192 len -= bytes; 1193 offset = 0; 1194 } 1195 1196 bio->bi_end_io = bio_map_kern_endio; 1197 return bio; 1198} 1199 1200/** 1201 * bio_map_kern - map kernel address into bio 1202 * @q: the struct request_queue for the bio 1203 * @data: pointer to buffer to map 1204 * @len: length in bytes 1205 * @gfp_mask: allocation flags for bio allocation 1206 * 1207 * Map the kernel address into a bio suitable for io to a block 1208 * device. Returns an error pointer in case of error. 1209 */ 1210struct bio *bio_map_kern(struct request_queue *q, void *data, unsigned int len, 1211 gfp_t gfp_mask) 1212{ 1213 struct bio *bio; 1214 1215 bio = __bio_map_kern(q, data, len, gfp_mask); 1216 if (IS_ERR(bio)) 1217 return bio; 1218 1219 if (bio->bi_size == len) 1220 return bio; 1221 1222 /* 1223 * Don't support partial mappings. 1224 */ 1225 bio_put(bio); 1226 return ERR_PTR(-EINVAL); 1227} 1228EXPORT_SYMBOL(bio_map_kern); 1229 1230static void bio_copy_kern_endio(struct bio *bio, int err) 1231{ 1232 struct bio_vec *bvec; 1233 const int read = bio_data_dir(bio) == READ; 1234 struct bio_map_data *bmd = bio->bi_private; 1235 int i; 1236 char *p = bmd->sgvecs[0].iov_base; 1237 1238 __bio_for_each_segment(bvec, bio, i, 0) { 1239 char *addr = page_address(bvec->bv_page); 1240 int len = bmd->iovecs[i].bv_len; 1241 1242 if (read) 1243 memcpy(p, addr, len); 1244 1245 __free_page(bvec->bv_page); 1246 p += len; 1247 } 1248 1249 bio_free_map_data(bmd); 1250 bio_put(bio); 1251} 1252 1253/** 1254 * bio_copy_kern - copy kernel address into bio 1255 * @q: the struct request_queue for the bio 1256 * @data: pointer to buffer to copy 1257 * @len: length in bytes 1258 * @gfp_mask: allocation flags for bio and page allocation 1259 * @reading: data direction is READ 1260 * 1261 * copy the kernel address into a bio suitable for io to a block 1262 * device. Returns an error pointer in case of error. 1263 */ 1264struct bio *bio_copy_kern(struct request_queue *q, void *data, unsigned int len, 1265 gfp_t gfp_mask, int reading) 1266{ 1267 struct bio *bio; 1268 struct bio_vec *bvec; 1269 int i; 1270 1271 bio = bio_copy_user(q, NULL, (unsigned long)data, len, 1, gfp_mask); 1272 if (IS_ERR(bio)) 1273 return bio; 1274 1275 if (!reading) { 1276 void *p = data; 1277 1278 bio_for_each_segment(bvec, bio, i) { 1279 char *addr = page_address(bvec->bv_page); 1280 1281 memcpy(addr, p, bvec->bv_len); 1282 p += bvec->bv_len; 1283 } 1284 } 1285 1286 bio->bi_end_io = bio_copy_kern_endio; 1287 1288 return bio; 1289} 1290EXPORT_SYMBOL(bio_copy_kern); 1291 1292/* 1293 * bio_set_pages_dirty() and bio_check_pages_dirty() are support functions 1294 * for performing direct-IO in BIOs. 1295 * 1296 * The problem is that we cannot run set_page_dirty() from interrupt context 1297 * because the required locks are not interrupt-safe. So what we can do is to 1298 * mark the pages dirty _before_ performing IO. And in interrupt context, 1299 * check that the pages are still dirty. If so, fine. If not, redirty them 1300 * in process context. 1301 * 1302 * We special-case compound pages here: normally this means reads into hugetlb 1303 * pages. The logic in here doesn't really work right for compound pages 1304 * because the VM does not uniformly chase down the head page in all cases. 1305 * But dirtiness of compound pages is pretty meaningless anyway: the VM doesn't 1306 * handle them at all. So we skip compound pages here at an early stage. 1307 * 1308 * Note that this code is very hard to test under normal circumstances because 1309 * direct-io pins the pages with get_user_pages(). This makes 1310 * is_page_cache_freeable return false, and the VM will not clean the pages. 1311 * But other code (eg, pdflush) could clean the pages if they are mapped 1312 * pagecache. 1313 * 1314 * Simply disabling the call to bio_set_pages_dirty() is a good way to test the 1315 * deferred bio dirtying paths. 1316 */ 1317 1318/* 1319 * bio_set_pages_dirty() will mark all the bio's pages as dirty. 1320 */ 1321void bio_set_pages_dirty(struct bio *bio) 1322{ 1323 struct bio_vec *bvec = bio->bi_io_vec; 1324 int i; 1325 1326 for (i = 0; i < bio->bi_vcnt; i++) { 1327 struct page *page = bvec[i].bv_page; 1328 1329 if (page && !PageCompound(page)) 1330 set_page_dirty_lock(page); 1331 } 1332} 1333 1334static void bio_release_pages(struct bio *bio) 1335{ 1336 struct bio_vec *bvec = bio->bi_io_vec; 1337 int i; 1338 1339 for (i = 0; i < bio->bi_vcnt; i++) { 1340 struct page *page = bvec[i].bv_page; 1341 1342 if (page) 1343 put_page(page); 1344 } 1345} 1346 1347/* 1348 * bio_check_pages_dirty() will check that all the BIO's pages are still dirty. 1349 * If they are, then fine. If, however, some pages are clean then they must 1350 * have been written out during the direct-IO read. So we take another ref on 1351 * the BIO and the offending pages and re-dirty the pages in process context. 1352 * 1353 * It is expected that bio_check_pages_dirty() will wholly own the BIO from 1354 * here on. It will run one page_cache_release() against each page and will 1355 * run one bio_put() against the BIO. 1356 */ 1357 1358static void bio_dirty_fn(struct work_struct *work); 1359 1360static DECLARE_WORK(bio_dirty_work, bio_dirty_fn); 1361static DEFINE_SPINLOCK(bio_dirty_lock); 1362static struct bio *bio_dirty_list; 1363 1364/* 1365 * This runs in process context 1366 */ 1367static void bio_dirty_fn(struct work_struct *work) 1368{ 1369 unsigned long flags; 1370 struct bio *bio; 1371 1372 spin_lock_irqsave(&bio_dirty_lock, flags); 1373 bio = bio_dirty_list; 1374 bio_dirty_list = NULL; 1375 spin_unlock_irqrestore(&bio_dirty_lock, flags); 1376 1377 while (bio) { 1378 struct bio *next = bio->bi_private; 1379 1380 bio_set_pages_dirty(bio); 1381 bio_release_pages(bio); 1382 bio_put(bio); 1383 bio = next; 1384 } 1385} 1386 1387void bio_check_pages_dirty(struct bio *bio) 1388{ 1389 struct bio_vec *bvec = bio->bi_io_vec; 1390 int nr_clean_pages = 0; 1391 int i; 1392 1393 for (i = 0; i < bio->bi_vcnt; i++) { 1394 struct page *page = bvec[i].bv_page; 1395 1396 if (PageDirty(page) || PageCompound(page)) { 1397 page_cache_release(page); 1398 bvec[i].bv_page = NULL; 1399 } else { 1400 nr_clean_pages++; 1401 } 1402 } 1403 1404 if (nr_clean_pages) { 1405 unsigned long flags; 1406 1407 spin_lock_irqsave(&bio_dirty_lock, flags); 1408 bio->bi_private = bio_dirty_list; 1409 bio_dirty_list = bio; 1410 spin_unlock_irqrestore(&bio_dirty_lock, flags); 1411 schedule_work(&bio_dirty_work); 1412 } else { 1413 bio_put(bio); 1414 } 1415} 1416 1417#if ARCH_IMPLEMENTS_FLUSH_DCACHE_PAGE 1418void bio_flush_dcache_pages(struct bio *bi) 1419{ 1420 int i; 1421 struct bio_vec *bvec; 1422 1423 bio_for_each_segment(bvec, bi, i) 1424 flush_dcache_page(bvec->bv_page); 1425} 1426EXPORT_SYMBOL(bio_flush_dcache_pages); 1427#endif 1428 1429/** 1430 * bio_endio - end I/O on a bio 1431 * @bio: bio 1432 * @error: error, if any 1433 * 1434 * Description: 1435 * bio_endio() will end I/O on the whole bio. bio_endio() is the 1436 * preferred way to end I/O on a bio, it takes care of clearing 1437 * BIO_UPTODATE on error. @error is 0 on success, and and one of the 1438 * established -Exxxx (-EIO, for instance) error values in case 1439 * something went wrong. Noone should call bi_end_io() directly on a 1440 * bio unless they own it and thus know that it has an end_io 1441 * function. 1442 **/ 1443void bio_endio(struct bio *bio, int error) 1444{ 1445 if (error) 1446 clear_bit(BIO_UPTODATE, &bio->bi_flags); 1447 else if (!test_bit(BIO_UPTODATE, &bio->bi_flags)) 1448 error = -EIO; 1449 1450 if (bio->bi_end_io) 1451 bio->bi_end_io(bio, error); 1452} 1453EXPORT_SYMBOL(bio_endio); 1454 1455void bio_pair_release(struct bio_pair *bp) 1456{ 1457 if (atomic_dec_and_test(&bp->cnt)) { 1458 struct bio *master = bp->bio1.bi_private; 1459 1460 bio_endio(master, bp->error); 1461 mempool_free(bp, bp->bio2.bi_private); 1462 } 1463} 1464EXPORT_SYMBOL(bio_pair_release); 1465 1466static void bio_pair_end_1(struct bio *bi, int err) 1467{ 1468 struct bio_pair *bp = container_of(bi, struct bio_pair, bio1); 1469 1470 if (err) 1471 bp->error = err; 1472 1473 bio_pair_release(bp); 1474} 1475 1476static void bio_pair_end_2(struct bio *bi, int err) 1477{ 1478 struct bio_pair *bp = container_of(bi, struct bio_pair, bio2); 1479 1480 if (err) 1481 bp->error = err; 1482 1483 bio_pair_release(bp); 1484} 1485 1486/* 1487 * split a bio - only worry about a bio with a single page in its iovec 1488 */ 1489struct bio_pair *bio_split(struct bio *bi, int first_sectors) 1490{ 1491 struct bio_pair *bp = mempool_alloc(bio_split_pool, GFP_NOIO); 1492 1493 if (!bp) 1494 return bp; 1495 1496 trace_block_split(bdev_get_queue(bi->bi_bdev), bi, 1497 bi->bi_sector + first_sectors); 1498 1499 BUG_ON(bi->bi_vcnt != 1); 1500 BUG_ON(bi->bi_idx != 0); 1501 atomic_set(&bp->cnt, 3); 1502 bp->error = 0; 1503 bp->bio1 = *bi; 1504 bp->bio2 = *bi; 1505 bp->bio2.bi_sector += first_sectors; 1506 bp->bio2.bi_size -= first_sectors << 9; 1507 bp->bio1.bi_size = first_sectors << 9; 1508 1509 bp->bv1 = bi->bi_io_vec[0]; 1510 bp->bv2 = bi->bi_io_vec[0]; 1511 bp->bv2.bv_offset += first_sectors << 9; 1512 bp->bv2.bv_len -= first_sectors << 9; 1513 bp->bv1.bv_len = first_sectors << 9; 1514 1515 bp->bio1.bi_io_vec = &bp->bv1; 1516 bp->bio2.bi_io_vec = &bp->bv2; 1517 1518 bp->bio1.bi_max_vecs = 1; 1519 bp->bio2.bi_max_vecs = 1; 1520 1521 bp->bio1.bi_end_io = bio_pair_end_1; 1522 bp->bio2.bi_end_io = bio_pair_end_2; 1523 1524 bp->bio1.bi_private = bi; 1525 bp->bio2.bi_private = bio_split_pool; 1526 1527 if (bio_integrity(bi)) 1528 bio_integrity_split(bi, bp, first_sectors); 1529 1530 return bp; 1531} 1532EXPORT_SYMBOL(bio_split); 1533 1534/** 1535 * bio_sector_offset - Find hardware sector offset in bio 1536 * @bio: bio to inspect 1537 * @index: bio_vec index 1538 * @offset: offset in bv_page 1539 * 1540 * Return the number of hardware sectors between beginning of bio 1541 * and an end point indicated by a bio_vec index and an offset 1542 * within that vector's page. 1543 */ 1544sector_t bio_sector_offset(struct bio *bio, unsigned short index, 1545 unsigned int offset) 1546{ 1547 unsigned int sector_sz; 1548 struct bio_vec *bv; 1549 sector_t sectors; 1550 int i; 1551 1552 sector_sz = queue_logical_block_size(bio->bi_bdev->bd_disk->queue); 1553 sectors = 0; 1554 1555 if (index >= bio->bi_idx) 1556 index = bio->bi_vcnt - 1; 1557 1558 __bio_for_each_segment(bv, bio, i, 0) { 1559 if (i == index) { 1560 if (offset > bv->bv_offset) 1561 sectors += (offset - bv->bv_offset) / sector_sz; 1562 break; 1563 } 1564 1565 sectors += bv->bv_len / sector_sz; 1566 } 1567 1568 return sectors; 1569} 1570EXPORT_SYMBOL(bio_sector_offset); 1571 1572/* 1573 * create memory pools for biovec's in a bio_set. 1574 * use the global biovec slabs created for general use. 1575 */ 1576static int biovec_create_pools(struct bio_set *bs, int pool_entries) 1577{ 1578 struct biovec_slab *bp = bvec_slabs + BIOVEC_MAX_IDX; 1579 1580 bs->bvec_pool = mempool_create_slab_pool(pool_entries, bp->slab); 1581 if (!bs->bvec_pool) 1582 return -ENOMEM; 1583 1584 return 0; 1585} 1586 1587static void biovec_free_pools(struct bio_set *bs) 1588{ 1589 mempool_destroy(bs->bvec_pool); 1590} 1591 1592void bioset_free(struct bio_set *bs) 1593{ 1594 if (bs->bio_pool) 1595 mempool_destroy(bs->bio_pool); 1596 1597 bioset_integrity_free(bs); 1598 biovec_free_pools(bs); 1599 bio_put_slab(bs); 1600 1601 kfree(bs); 1602} 1603EXPORT_SYMBOL(bioset_free); 1604 1605/** 1606 * bioset_create - Create a bio_set 1607 * @pool_size: Number of bio and bio_vecs to cache in the mempool 1608 * @front_pad: Number of bytes to allocate in front of the returned bio 1609 * 1610 * Description: 1611 * Set up a bio_set to be used with @bio_alloc_bioset. Allows the caller 1612 * to ask for a number of bytes to be allocated in front of the bio. 1613 * Front pad allocation is useful for embedding the bio inside 1614 * another structure, to avoid allocating extra data to go with the bio. 1615 * Note that the bio must be embedded at the END of that structure always, 1616 * or things will break badly. 1617 */ 1618struct bio_set *bioset_create(unsigned int pool_size, unsigned int front_pad) 1619{ 1620 unsigned int back_pad = BIO_INLINE_VECS * sizeof(struct bio_vec); 1621 struct bio_set *bs; 1622 1623 bs = kzalloc(sizeof(*bs), GFP_KERNEL); 1624 if (!bs) 1625 return NULL; 1626 1627 bs->front_pad = front_pad; 1628 1629 bs->bio_slab = bio_find_or_create_slab(front_pad + back_pad); 1630 if (!bs->bio_slab) { 1631 kfree(bs); 1632 return NULL; 1633 } 1634 1635 bs->bio_pool = mempool_create_slab_pool(pool_size, bs->bio_slab); 1636 if (!bs->bio_pool) 1637 goto bad; 1638 1639 if (bioset_integrity_create(bs, pool_size)) 1640 goto bad; 1641 1642 if (!biovec_create_pools(bs, pool_size)) 1643 return bs; 1644 1645bad: 1646 bioset_free(bs); 1647 return NULL; 1648} 1649EXPORT_SYMBOL(bioset_create); 1650 1651static void __init biovec_init_slabs(void) 1652{ 1653 int i; 1654 1655 for (i = 0; i < BIOVEC_NR_POOLS; i++) { 1656 int size; 1657 struct biovec_slab *bvs = bvec_slabs + i; 1658 1659#ifndef CONFIG_BLK_DEV_INTEGRITY 1660 if (bvs->nr_vecs <= BIO_INLINE_VECS) { 1661 bvs->slab = NULL; 1662 continue; 1663 } 1664#endif 1665 1666 size = bvs->nr_vecs * sizeof(struct bio_vec); 1667 bvs->slab = kmem_cache_create(bvs->name, size, 0, 1668 SLAB_HWCACHE_ALIGN|SLAB_PANIC, NULL); 1669 } 1670} 1671 1672static int __init init_bio(void) 1673{ 1674 bio_slab_max = 2; 1675 bio_slab_nr = 0; 1676 bio_slabs = kzalloc(bio_slab_max * sizeof(struct bio_slab), GFP_KERNEL); 1677 if (!bio_slabs) 1678 panic("bio: can't allocate bios\n"); 1679 1680 bio_integrity_init(); 1681 biovec_init_slabs(); 1682 1683 fs_bio_set = bioset_create(BIO_POOL_SIZE, 0); 1684 if (!fs_bio_set) 1685 panic("bio: can't allocate bios\n"); 1686 1687 bio_split_pool = mempool_create_kmalloc_pool(BIO_SPLIT_ENTRIES, 1688 sizeof(struct bio_pair)); 1689 if (!bio_split_pool) 1690 panic("bio: can't create split pool\n"); 1691 1692 return 0; 1693} 1694subsys_initcall(init_bio); 1695