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/uio.h> 23 #include <linux/iocontext.h> 24 #include <linux/slab.h> 25 #include <linux/init.h> 26 #include <linux/kernel.h> 27 #include <linux/export.h> 28 #include <linux/mempool.h> 29 #include <linux/workqueue.h> 30 #include <linux/cgroup.h> 31 #include <linux/blk-cgroup.h> 32 33 #include <trace/events/block.h> 34 #include "blk.h" 35 #include "blk-rq-qos.h" 36 37 /* 38 * Test patch to inline a certain number of bi_io_vec's inside the bio 39 * itself, to shrink a bio data allocation from two mempool calls to one 40 */ 41 #define BIO_INLINE_VECS 4 42 43 /* 44 * if you change this list, also change bvec_alloc or things will 45 * break badly! cannot be bigger than what you can fit into an 46 * unsigned short 47 */ 48 #define BV(x, n) { .nr_vecs = x, .name = "biovec-"#n } 49 static struct biovec_slab bvec_slabs[BVEC_POOL_NR] __read_mostly = { 50 BV(1, 1), BV(4, 4), BV(16, 16), BV(64, 64), BV(128, 128), BV(BIO_MAX_PAGES, max), 51 }; 52 #undef BV 53 54 /* 55 * fs_bio_set is the bio_set containing bio and iovec memory pools used by 56 * IO code that does not need private memory pools. 57 */ 58 struct bio_set fs_bio_set; 59 EXPORT_SYMBOL(fs_bio_set); 60 61 /* 62 * Our slab pool management 63 */ 64 struct bio_slab { 65 struct kmem_cache *slab; 66 unsigned int slab_ref; 67 unsigned int slab_size; 68 char name[8]; 69 }; 70 static DEFINE_MUTEX(bio_slab_lock); 71 static struct bio_slab *bio_slabs; 72 static unsigned int bio_slab_nr, bio_slab_max; 73 74 static struct kmem_cache *bio_find_or_create_slab(unsigned int extra_size) 75 { 76 unsigned int sz = sizeof(struct bio) + extra_size; 77 struct kmem_cache *slab = NULL; 78 struct bio_slab *bslab, *new_bio_slabs; 79 unsigned int new_bio_slab_max; 80 unsigned int i, entry = -1; 81 82 mutex_lock(&bio_slab_lock); 83 84 i = 0; 85 while (i < bio_slab_nr) { 86 bslab = &bio_slabs[i]; 87 88 if (!bslab->slab && entry == -1) 89 entry = i; 90 else if (bslab->slab_size == sz) { 91 slab = bslab->slab; 92 bslab->slab_ref++; 93 break; 94 } 95 i++; 96 } 97 98 if (slab) 99 goto out_unlock; 100 101 if (bio_slab_nr == bio_slab_max && entry == -1) { 102 new_bio_slab_max = bio_slab_max << 1; 103 new_bio_slabs = krealloc(bio_slabs, 104 new_bio_slab_max * sizeof(struct bio_slab), 105 GFP_KERNEL); 106 if (!new_bio_slabs) 107 goto out_unlock; 108 bio_slab_max = new_bio_slab_max; 109 bio_slabs = new_bio_slabs; 110 } 111 if (entry == -1) 112 entry = bio_slab_nr++; 113 114 bslab = &bio_slabs[entry]; 115 116 snprintf(bslab->name, sizeof(bslab->name), "bio-%d", entry); 117 slab = kmem_cache_create(bslab->name, sz, ARCH_KMALLOC_MINALIGN, 118 SLAB_HWCACHE_ALIGN, NULL); 119 if (!slab) 120 goto out_unlock; 121 122 bslab->slab = slab; 123 bslab->slab_ref = 1; 124 bslab->slab_size = sz; 125 out_unlock: 126 mutex_unlock(&bio_slab_lock); 127 return slab; 128 } 129 130 static void bio_put_slab(struct bio_set *bs) 131 { 132 struct bio_slab *bslab = NULL; 133 unsigned int i; 134 135 mutex_lock(&bio_slab_lock); 136 137 for (i = 0; i < bio_slab_nr; i++) { 138 if (bs->bio_slab == bio_slabs[i].slab) { 139 bslab = &bio_slabs[i]; 140 break; 141 } 142 } 143 144 if (WARN(!bslab, KERN_ERR "bio: unable to find slab!\n")) 145 goto out; 146 147 WARN_ON(!bslab->slab_ref); 148 149 if (--bslab->slab_ref) 150 goto out; 151 152 kmem_cache_destroy(bslab->slab); 153 bslab->slab = NULL; 154 155 out: 156 mutex_unlock(&bio_slab_lock); 157 } 158 159 unsigned int bvec_nr_vecs(unsigned short idx) 160 { 161 return bvec_slabs[idx].nr_vecs; 162 } 163 164 void bvec_free(mempool_t *pool, struct bio_vec *bv, unsigned int idx) 165 { 166 if (!idx) 167 return; 168 idx--; 169 170 BIO_BUG_ON(idx >= BVEC_POOL_NR); 171 172 if (idx == BVEC_POOL_MAX) { 173 mempool_free(bv, pool); 174 } else { 175 struct biovec_slab *bvs = bvec_slabs + idx; 176 177 kmem_cache_free(bvs->slab, bv); 178 } 179 } 180 181 struct bio_vec *bvec_alloc(gfp_t gfp_mask, int nr, unsigned long *idx, 182 mempool_t *pool) 183 { 184 struct bio_vec *bvl; 185 186 /* 187 * see comment near bvec_array define! 188 */ 189 switch (nr) { 190 case 1: 191 *idx = 0; 192 break; 193 case 2 ... 4: 194 *idx = 1; 195 break; 196 case 5 ... 16: 197 *idx = 2; 198 break; 199 case 17 ... 64: 200 *idx = 3; 201 break; 202 case 65 ... 128: 203 *idx = 4; 204 break; 205 case 129 ... BIO_MAX_PAGES: 206 *idx = 5; 207 break; 208 default: 209 return NULL; 210 } 211 212 /* 213 * idx now points to the pool we want to allocate from. only the 214 * 1-vec entry pool is mempool backed. 215 */ 216 if (*idx == BVEC_POOL_MAX) { 217 fallback: 218 bvl = mempool_alloc(pool, gfp_mask); 219 } else { 220 struct biovec_slab *bvs = bvec_slabs + *idx; 221 gfp_t __gfp_mask = gfp_mask & ~(__GFP_DIRECT_RECLAIM | __GFP_IO); 222 223 /* 224 * Make this allocation restricted and don't dump info on 225 * allocation failures, since we'll fallback to the mempool 226 * in case of failure. 227 */ 228 __gfp_mask |= __GFP_NOMEMALLOC | __GFP_NORETRY | __GFP_NOWARN; 229 230 /* 231 * Try a slab allocation. If this fails and __GFP_DIRECT_RECLAIM 232 * is set, retry with the 1-entry mempool 233 */ 234 bvl = kmem_cache_alloc(bvs->slab, __gfp_mask); 235 if (unlikely(!bvl && (gfp_mask & __GFP_DIRECT_RECLAIM))) { 236 *idx = BVEC_POOL_MAX; 237 goto fallback; 238 } 239 } 240 241 (*idx)++; 242 return bvl; 243 } 244 245 void bio_uninit(struct bio *bio) 246 { 247 bio_disassociate_task(bio); 248 } 249 EXPORT_SYMBOL(bio_uninit); 250 251 static void bio_free(struct bio *bio) 252 { 253 struct bio_set *bs = bio->bi_pool; 254 void *p; 255 256 bio_uninit(bio); 257 258 if (bs) { 259 bvec_free(&bs->bvec_pool, bio->bi_io_vec, BVEC_POOL_IDX(bio)); 260 261 /* 262 * If we have front padding, adjust the bio pointer before freeing 263 */ 264 p = bio; 265 p -= bs->front_pad; 266 267 mempool_free(p, &bs->bio_pool); 268 } else { 269 /* Bio was allocated by bio_kmalloc() */ 270 kfree(bio); 271 } 272 } 273 274 /* 275 * Users of this function have their own bio allocation. Subsequently, 276 * they must remember to pair any call to bio_init() with bio_uninit() 277 * when IO has completed, or when the bio is released. 278 */ 279 void bio_init(struct bio *bio, struct bio_vec *table, 280 unsigned short max_vecs) 281 { 282 memset(bio, 0, sizeof(*bio)); 283 atomic_set(&bio->__bi_remaining, 1); 284 atomic_set(&bio->__bi_cnt, 1); 285 286 bio->bi_io_vec = table; 287 bio->bi_max_vecs = max_vecs; 288 } 289 EXPORT_SYMBOL(bio_init); 290 291 /** 292 * bio_reset - reinitialize a bio 293 * @bio: bio to reset 294 * 295 * Description: 296 * After calling bio_reset(), @bio will be in the same state as a freshly 297 * allocated bio returned bio bio_alloc_bioset() - the only fields that are 298 * preserved are the ones that are initialized by bio_alloc_bioset(). See 299 * comment in struct bio. 300 */ 301 void bio_reset(struct bio *bio) 302 { 303 unsigned long flags = bio->bi_flags & (~0UL << BIO_RESET_BITS); 304 305 bio_uninit(bio); 306 307 memset(bio, 0, BIO_RESET_BYTES); 308 bio->bi_flags = flags; 309 atomic_set(&bio->__bi_remaining, 1); 310 } 311 EXPORT_SYMBOL(bio_reset); 312 313 static struct bio *__bio_chain_endio(struct bio *bio) 314 { 315 struct bio *parent = bio->bi_private; 316 317 if (!parent->bi_status) 318 parent->bi_status = bio->bi_status; 319 bio_put(bio); 320 return parent; 321 } 322 323 static void bio_chain_endio(struct bio *bio) 324 { 325 bio_endio(__bio_chain_endio(bio)); 326 } 327 328 /** 329 * bio_chain - chain bio completions 330 * @bio: the target bio 331 * @parent: the @bio's parent bio 332 * 333 * The caller won't have a bi_end_io called when @bio completes - instead, 334 * @parent's bi_end_io won't be called until both @parent and @bio have 335 * completed; the chained bio will also be freed when it completes. 336 * 337 * The caller must not set bi_private or bi_end_io in @bio. 338 */ 339 void bio_chain(struct bio *bio, struct bio *parent) 340 { 341 BUG_ON(bio->bi_private || bio->bi_end_io); 342 343 bio->bi_private = parent; 344 bio->bi_end_io = bio_chain_endio; 345 bio_inc_remaining(parent); 346 } 347 EXPORT_SYMBOL(bio_chain); 348 349 static void bio_alloc_rescue(struct work_struct *work) 350 { 351 struct bio_set *bs = container_of(work, struct bio_set, rescue_work); 352 struct bio *bio; 353 354 while (1) { 355 spin_lock(&bs->rescue_lock); 356 bio = bio_list_pop(&bs->rescue_list); 357 spin_unlock(&bs->rescue_lock); 358 359 if (!bio) 360 break; 361 362 generic_make_request(bio); 363 } 364 } 365 366 static void punt_bios_to_rescuer(struct bio_set *bs) 367 { 368 struct bio_list punt, nopunt; 369 struct bio *bio; 370 371 if (WARN_ON_ONCE(!bs->rescue_workqueue)) 372 return; 373 /* 374 * In order to guarantee forward progress we must punt only bios that 375 * were allocated from this bio_set; otherwise, if there was a bio on 376 * there for a stacking driver higher up in the stack, processing it 377 * could require allocating bios from this bio_set, and doing that from 378 * our own rescuer would be bad. 379 * 380 * Since bio lists are singly linked, pop them all instead of trying to 381 * remove from the middle of the list: 382 */ 383 384 bio_list_init(&punt); 385 bio_list_init(&nopunt); 386 387 while ((bio = bio_list_pop(¤t->bio_list[0]))) 388 bio_list_add(bio->bi_pool == bs ? &punt : &nopunt, bio); 389 current->bio_list[0] = nopunt; 390 391 bio_list_init(&nopunt); 392 while ((bio = bio_list_pop(¤t->bio_list[1]))) 393 bio_list_add(bio->bi_pool == bs ? &punt : &nopunt, bio); 394 current->bio_list[1] = nopunt; 395 396 spin_lock(&bs->rescue_lock); 397 bio_list_merge(&bs->rescue_list, &punt); 398 spin_unlock(&bs->rescue_lock); 399 400 queue_work(bs->rescue_workqueue, &bs->rescue_work); 401 } 402 403 /** 404 * bio_alloc_bioset - allocate a bio for I/O 405 * @gfp_mask: the GFP_* mask given to the slab allocator 406 * @nr_iovecs: number of iovecs to pre-allocate 407 * @bs: the bio_set to allocate from. 408 * 409 * Description: 410 * If @bs is NULL, uses kmalloc() to allocate the bio; else the allocation is 411 * backed by the @bs's mempool. 412 * 413 * When @bs is not NULL, if %__GFP_DIRECT_RECLAIM is set then bio_alloc will 414 * always be able to allocate a bio. This is due to the mempool guarantees. 415 * To make this work, callers must never allocate more than 1 bio at a time 416 * from this pool. Callers that need to allocate more than 1 bio must always 417 * submit the previously allocated bio for IO before attempting to allocate 418 * a new one. Failure to do so can cause deadlocks under memory pressure. 419 * 420 * Note that when running under generic_make_request() (i.e. any block 421 * driver), bios are not submitted until after you return - see the code in 422 * generic_make_request() that converts recursion into iteration, to prevent 423 * stack overflows. 424 * 425 * This would normally mean allocating multiple bios under 426 * generic_make_request() would be susceptible to deadlocks, but we have 427 * deadlock avoidance code that resubmits any blocked bios from a rescuer 428 * thread. 429 * 430 * However, we do not guarantee forward progress for allocations from other 431 * mempools. Doing multiple allocations from the same mempool under 432 * generic_make_request() should be avoided - instead, use bio_set's front_pad 433 * for per bio allocations. 434 * 435 * RETURNS: 436 * Pointer to new bio on success, NULL on failure. 437 */ 438 struct bio *bio_alloc_bioset(gfp_t gfp_mask, unsigned int nr_iovecs, 439 struct bio_set *bs) 440 { 441 gfp_t saved_gfp = gfp_mask; 442 unsigned front_pad; 443 unsigned inline_vecs; 444 struct bio_vec *bvl = NULL; 445 struct bio *bio; 446 void *p; 447 448 if (!bs) { 449 if (nr_iovecs > UIO_MAXIOV) 450 return NULL; 451 452 p = kmalloc(sizeof(struct bio) + 453 nr_iovecs * sizeof(struct bio_vec), 454 gfp_mask); 455 front_pad = 0; 456 inline_vecs = nr_iovecs; 457 } else { 458 /* should not use nobvec bioset for nr_iovecs > 0 */ 459 if (WARN_ON_ONCE(!mempool_initialized(&bs->bvec_pool) && 460 nr_iovecs > 0)) 461 return NULL; 462 /* 463 * generic_make_request() converts recursion to iteration; this 464 * means if we're running beneath it, any bios we allocate and 465 * submit will not be submitted (and thus freed) until after we 466 * return. 467 * 468 * This exposes us to a potential deadlock if we allocate 469 * multiple bios from the same bio_set() while running 470 * underneath generic_make_request(). If we were to allocate 471 * multiple bios (say a stacking block driver that was splitting 472 * bios), we would deadlock if we exhausted the mempool's 473 * reserve. 474 * 475 * We solve this, and guarantee forward progress, with a rescuer 476 * workqueue per bio_set. If we go to allocate and there are 477 * bios on current->bio_list, we first try the allocation 478 * without __GFP_DIRECT_RECLAIM; if that fails, we punt those 479 * bios we would be blocking to the rescuer workqueue before 480 * we retry with the original gfp_flags. 481 */ 482 483 if (current->bio_list && 484 (!bio_list_empty(¤t->bio_list[0]) || 485 !bio_list_empty(¤t->bio_list[1])) && 486 bs->rescue_workqueue) 487 gfp_mask &= ~__GFP_DIRECT_RECLAIM; 488 489 p = mempool_alloc(&bs->bio_pool, gfp_mask); 490 if (!p && gfp_mask != saved_gfp) { 491 punt_bios_to_rescuer(bs); 492 gfp_mask = saved_gfp; 493 p = mempool_alloc(&bs->bio_pool, gfp_mask); 494 } 495 496 front_pad = bs->front_pad; 497 inline_vecs = BIO_INLINE_VECS; 498 } 499 500 if (unlikely(!p)) 501 return NULL; 502 503 bio = p + front_pad; 504 bio_init(bio, NULL, 0); 505 506 if (nr_iovecs > inline_vecs) { 507 unsigned long idx = 0; 508 509 bvl = bvec_alloc(gfp_mask, nr_iovecs, &idx, &bs->bvec_pool); 510 if (!bvl && gfp_mask != saved_gfp) { 511 punt_bios_to_rescuer(bs); 512 gfp_mask = saved_gfp; 513 bvl = bvec_alloc(gfp_mask, nr_iovecs, &idx, &bs->bvec_pool); 514 } 515 516 if (unlikely(!bvl)) 517 goto err_free; 518 519 bio->bi_flags |= idx << BVEC_POOL_OFFSET; 520 } else if (nr_iovecs) { 521 bvl = bio->bi_inline_vecs; 522 } 523 524 bio->bi_pool = bs; 525 bio->bi_max_vecs = nr_iovecs; 526 bio->bi_io_vec = bvl; 527 return bio; 528 529 err_free: 530 mempool_free(p, &bs->bio_pool); 531 return NULL; 532 } 533 EXPORT_SYMBOL(bio_alloc_bioset); 534 535 void zero_fill_bio_iter(struct bio *bio, struct bvec_iter start) 536 { 537 unsigned long flags; 538 struct bio_vec bv; 539 struct bvec_iter iter; 540 541 __bio_for_each_segment(bv, bio, iter, start) { 542 char *data = bvec_kmap_irq(&bv, &flags); 543 memset(data, 0, bv.bv_len); 544 flush_dcache_page(bv.bv_page); 545 bvec_kunmap_irq(data, &flags); 546 } 547 } 548 EXPORT_SYMBOL(zero_fill_bio_iter); 549 550 /** 551 * bio_put - release a reference to a bio 552 * @bio: bio to release reference to 553 * 554 * Description: 555 * Put a reference to a &struct bio, either one you have gotten with 556 * bio_alloc, bio_get or bio_clone_*. The last put of a bio will free it. 557 **/ 558 void bio_put(struct bio *bio) 559 { 560 if (!bio_flagged(bio, BIO_REFFED)) 561 bio_free(bio); 562 else { 563 BIO_BUG_ON(!atomic_read(&bio->__bi_cnt)); 564 565 /* 566 * last put frees it 567 */ 568 if (atomic_dec_and_test(&bio->__bi_cnt)) 569 bio_free(bio); 570 } 571 } 572 EXPORT_SYMBOL(bio_put); 573 574 inline int bio_phys_segments(struct request_queue *q, struct bio *bio) 575 { 576 if (unlikely(!bio_flagged(bio, BIO_SEG_VALID))) 577 blk_recount_segments(q, bio); 578 579 return bio->bi_phys_segments; 580 } 581 EXPORT_SYMBOL(bio_phys_segments); 582 583 /** 584 * __bio_clone_fast - clone a bio that shares the original bio's biovec 585 * @bio: destination bio 586 * @bio_src: bio to clone 587 * 588 * Clone a &bio. Caller will own the returned bio, but not 589 * the actual data it points to. Reference count of returned 590 * bio will be one. 591 * 592 * Caller must ensure that @bio_src is not freed before @bio. 593 */ 594 void __bio_clone_fast(struct bio *bio, struct bio *bio_src) 595 { 596 BUG_ON(bio->bi_pool && BVEC_POOL_IDX(bio)); 597 598 /* 599 * most users will be overriding ->bi_disk with a new target, 600 * so we don't set nor calculate new physical/hw segment counts here 601 */ 602 bio->bi_disk = bio_src->bi_disk; 603 bio->bi_partno = bio_src->bi_partno; 604 bio_set_flag(bio, BIO_CLONED); 605 if (bio_flagged(bio_src, BIO_THROTTLED)) 606 bio_set_flag(bio, BIO_THROTTLED); 607 bio->bi_opf = bio_src->bi_opf; 608 bio->bi_write_hint = bio_src->bi_write_hint; 609 bio->bi_iter = bio_src->bi_iter; 610 bio->bi_io_vec = bio_src->bi_io_vec; 611 612 bio_clone_blkcg_association(bio, bio_src); 613 } 614 EXPORT_SYMBOL(__bio_clone_fast); 615 616 /** 617 * bio_clone_fast - clone a bio that shares the original bio's biovec 618 * @bio: bio to clone 619 * @gfp_mask: allocation priority 620 * @bs: bio_set to allocate from 621 * 622 * Like __bio_clone_fast, only also allocates the returned bio 623 */ 624 struct bio *bio_clone_fast(struct bio *bio, gfp_t gfp_mask, struct bio_set *bs) 625 { 626 struct bio *b; 627 628 b = bio_alloc_bioset(gfp_mask, 0, bs); 629 if (!b) 630 return NULL; 631 632 __bio_clone_fast(b, bio); 633 634 if (bio_integrity(bio)) { 635 int ret; 636 637 ret = bio_integrity_clone(b, bio, gfp_mask); 638 639 if (ret < 0) { 640 bio_put(b); 641 return NULL; 642 } 643 } 644 645 return b; 646 } 647 EXPORT_SYMBOL(bio_clone_fast); 648 649 /** 650 * bio_clone_bioset - clone a bio 651 * @bio_src: bio to clone 652 * @gfp_mask: allocation priority 653 * @bs: bio_set to allocate from 654 * 655 * Clone bio. Caller will own the returned bio, but not the actual data it 656 * points to. Reference count of returned bio will be one. 657 */ 658 struct bio *bio_clone_bioset(struct bio *bio_src, gfp_t gfp_mask, 659 struct bio_set *bs) 660 { 661 struct bvec_iter iter; 662 struct bio_vec bv; 663 struct bio *bio; 664 665 /* 666 * Pre immutable biovecs, __bio_clone() used to just do a memcpy from 667 * bio_src->bi_io_vec to bio->bi_io_vec. 668 * 669 * We can't do that anymore, because: 670 * 671 * - The point of cloning the biovec is to produce a bio with a biovec 672 * the caller can modify: bi_idx and bi_bvec_done should be 0. 673 * 674 * - The original bio could've had more than BIO_MAX_PAGES biovecs; if 675 * we tried to clone the whole thing bio_alloc_bioset() would fail. 676 * But the clone should succeed as long as the number of biovecs we 677 * actually need to allocate is fewer than BIO_MAX_PAGES. 678 * 679 * - Lastly, bi_vcnt should not be looked at or relied upon by code 680 * that does not own the bio - reason being drivers don't use it for 681 * iterating over the biovec anymore, so expecting it to be kept up 682 * to date (i.e. for clones that share the parent biovec) is just 683 * asking for trouble and would force extra work on 684 * __bio_clone_fast() anyways. 685 */ 686 687 bio = bio_alloc_bioset(gfp_mask, bio_segments(bio_src), bs); 688 if (!bio) 689 return NULL; 690 bio->bi_disk = bio_src->bi_disk; 691 bio->bi_opf = bio_src->bi_opf; 692 bio->bi_write_hint = bio_src->bi_write_hint; 693 bio->bi_iter.bi_sector = bio_src->bi_iter.bi_sector; 694 bio->bi_iter.bi_size = bio_src->bi_iter.bi_size; 695 696 switch (bio_op(bio)) { 697 case REQ_OP_DISCARD: 698 case REQ_OP_SECURE_ERASE: 699 case REQ_OP_WRITE_ZEROES: 700 break; 701 case REQ_OP_WRITE_SAME: 702 bio->bi_io_vec[bio->bi_vcnt++] = bio_src->bi_io_vec[0]; 703 break; 704 default: 705 bio_for_each_segment(bv, bio_src, iter) 706 bio->bi_io_vec[bio->bi_vcnt++] = bv; 707 break; 708 } 709 710 if (bio_integrity(bio_src)) { 711 int ret; 712 713 ret = bio_integrity_clone(bio, bio_src, gfp_mask); 714 if (ret < 0) { 715 bio_put(bio); 716 return NULL; 717 } 718 } 719 720 bio_clone_blkcg_association(bio, bio_src); 721 722 return bio; 723 } 724 EXPORT_SYMBOL(bio_clone_bioset); 725 726 /** 727 * bio_add_pc_page - attempt to add page to bio 728 * @q: the target queue 729 * @bio: destination bio 730 * @page: page to add 731 * @len: vec entry length 732 * @offset: vec entry offset 733 * 734 * Attempt to add a page to the bio_vec maplist. This can fail for a 735 * number of reasons, such as the bio being full or target block device 736 * limitations. The target block device must allow bio's up to PAGE_SIZE, 737 * so it is always possible to add a single page to an empty bio. 738 * 739 * This should only be used by REQ_PC bios. 740 */ 741 int bio_add_pc_page(struct request_queue *q, struct bio *bio, struct page 742 *page, unsigned int len, unsigned int offset) 743 { 744 int retried_segments = 0; 745 struct bio_vec *bvec; 746 747 /* 748 * cloned bio must not modify vec list 749 */ 750 if (unlikely(bio_flagged(bio, BIO_CLONED))) 751 return 0; 752 753 if (((bio->bi_iter.bi_size + len) >> 9) > queue_max_hw_sectors(q)) 754 return 0; 755 756 /* 757 * For filesystems with a blocksize smaller than the pagesize 758 * we will often be called with the same page as last time and 759 * a consecutive offset. Optimize this special case. 760 */ 761 if (bio->bi_vcnt > 0) { 762 struct bio_vec *prev = &bio->bi_io_vec[bio->bi_vcnt - 1]; 763 764 if (page == prev->bv_page && 765 offset == prev->bv_offset + prev->bv_len) { 766 prev->bv_len += len; 767 bio->bi_iter.bi_size += len; 768 goto done; 769 } 770 771 /* 772 * If the queue doesn't support SG gaps and adding this 773 * offset would create a gap, disallow it. 774 */ 775 if (bvec_gap_to_prev(q, prev, offset)) 776 return 0; 777 } 778 779 if (bio_full(bio)) 780 return 0; 781 782 /* 783 * setup the new entry, we might clear it again later if we 784 * cannot add the page 785 */ 786 bvec = &bio->bi_io_vec[bio->bi_vcnt]; 787 bvec->bv_page = page; 788 bvec->bv_len = len; 789 bvec->bv_offset = offset; 790 bio->bi_vcnt++; 791 bio->bi_phys_segments++; 792 bio->bi_iter.bi_size += len; 793 794 /* 795 * Perform a recount if the number of segments is greater 796 * than queue_max_segments(q). 797 */ 798 799 while (bio->bi_phys_segments > queue_max_segments(q)) { 800 801 if (retried_segments) 802 goto failed; 803 804 retried_segments = 1; 805 blk_recount_segments(q, bio); 806 } 807 808 /* If we may be able to merge these biovecs, force a recount */ 809 if (bio->bi_vcnt > 1 && (BIOVEC_PHYS_MERGEABLE(bvec-1, bvec))) 810 bio_clear_flag(bio, BIO_SEG_VALID); 811 812 done: 813 return len; 814 815 failed: 816 bvec->bv_page = NULL; 817 bvec->bv_len = 0; 818 bvec->bv_offset = 0; 819 bio->bi_vcnt--; 820 bio->bi_iter.bi_size -= len; 821 blk_recount_segments(q, bio); 822 return 0; 823 } 824 EXPORT_SYMBOL(bio_add_pc_page); 825 826 /** 827 * __bio_try_merge_page - try appending data to an existing bvec. 828 * @bio: destination bio 829 * @page: page to add 830 * @len: length of the data to add 831 * @off: offset of the data in @page 832 * 833 * Try to add the data at @page + @off to the last bvec of @bio. This is a 834 * a useful optimisation for file systems with a block size smaller than the 835 * page size. 836 * 837 * Return %true on success or %false on failure. 838 */ 839 bool __bio_try_merge_page(struct bio *bio, struct page *page, 840 unsigned int len, unsigned int off) 841 { 842 if (WARN_ON_ONCE(bio_flagged(bio, BIO_CLONED))) 843 return false; 844 845 if (bio->bi_vcnt > 0) { 846 struct bio_vec *bv = &bio->bi_io_vec[bio->bi_vcnt - 1]; 847 848 if (page == bv->bv_page && off == bv->bv_offset + bv->bv_len) { 849 bv->bv_len += len; 850 bio->bi_iter.bi_size += len; 851 return true; 852 } 853 } 854 return false; 855 } 856 EXPORT_SYMBOL_GPL(__bio_try_merge_page); 857 858 /** 859 * __bio_add_page - add page to a bio in a new segment 860 * @bio: destination bio 861 * @page: page to add 862 * @len: length of the data to add 863 * @off: offset of the data in @page 864 * 865 * Add the data at @page + @off to @bio as a new bvec. The caller must ensure 866 * that @bio has space for another bvec. 867 */ 868 void __bio_add_page(struct bio *bio, struct page *page, 869 unsigned int len, unsigned int off) 870 { 871 struct bio_vec *bv = &bio->bi_io_vec[bio->bi_vcnt]; 872 873 WARN_ON_ONCE(bio_flagged(bio, BIO_CLONED)); 874 WARN_ON_ONCE(bio_full(bio)); 875 876 bv->bv_page = page; 877 bv->bv_offset = off; 878 bv->bv_len = len; 879 880 bio->bi_iter.bi_size += len; 881 bio->bi_vcnt++; 882 } 883 EXPORT_SYMBOL_GPL(__bio_add_page); 884 885 /** 886 * bio_add_page - attempt to add page to bio 887 * @bio: destination bio 888 * @page: page to add 889 * @len: vec entry length 890 * @offset: vec entry offset 891 * 892 * Attempt to add a page to the bio_vec maplist. This will only fail 893 * if either bio->bi_vcnt == bio->bi_max_vecs or it's a cloned bio. 894 */ 895 int bio_add_page(struct bio *bio, struct page *page, 896 unsigned int len, unsigned int offset) 897 { 898 if (!__bio_try_merge_page(bio, page, len, offset)) { 899 if (bio_full(bio)) 900 return 0; 901 __bio_add_page(bio, page, len, offset); 902 } 903 return len; 904 } 905 EXPORT_SYMBOL(bio_add_page); 906 907 /** 908 * bio_iov_iter_get_pages - pin user or kernel pages and add them to a bio 909 * @bio: bio to add pages to 910 * @iter: iov iterator describing the region to be mapped 911 * 912 * Pins as many pages from *iter and appends them to @bio's bvec array. The 913 * pages will have to be released using put_page() when done. 914 */ 915 int bio_iov_iter_get_pages(struct bio *bio, struct iov_iter *iter) 916 { 917 unsigned short nr_pages = bio->bi_max_vecs - bio->bi_vcnt; 918 struct bio_vec *bv = bio->bi_io_vec + bio->bi_vcnt; 919 struct page **pages = (struct page **)bv; 920 size_t offset, diff; 921 ssize_t size; 922 923 size = iov_iter_get_pages(iter, pages, LONG_MAX, nr_pages, &offset); 924 if (unlikely(size <= 0)) 925 return size ? size : -EFAULT; 926 nr_pages = (size + offset + PAGE_SIZE - 1) / PAGE_SIZE; 927 928 /* 929 * Deep magic below: We need to walk the pinned pages backwards 930 * because we are abusing the space allocated for the bio_vecs 931 * for the page array. Because the bio_vecs are larger than the 932 * page pointers by definition this will always work. But it also 933 * means we can't use bio_add_page, so any changes to it's semantics 934 * need to be reflected here as well. 935 */ 936 bio->bi_iter.bi_size += size; 937 bio->bi_vcnt += nr_pages; 938 939 diff = (nr_pages * PAGE_SIZE - offset) - size; 940 while (nr_pages--) { 941 bv[nr_pages].bv_page = pages[nr_pages]; 942 bv[nr_pages].bv_len = PAGE_SIZE; 943 bv[nr_pages].bv_offset = 0; 944 } 945 946 bv[0].bv_offset += offset; 947 bv[0].bv_len -= offset; 948 if (diff) 949 bv[bio->bi_vcnt - 1].bv_len -= diff; 950 951 iov_iter_advance(iter, size); 952 return 0; 953 } 954 EXPORT_SYMBOL_GPL(bio_iov_iter_get_pages); 955 956 static void submit_bio_wait_endio(struct bio *bio) 957 { 958 complete(bio->bi_private); 959 } 960 961 /** 962 * submit_bio_wait - submit a bio, and wait until it completes 963 * @bio: The &struct bio which describes the I/O 964 * 965 * Simple wrapper around submit_bio(). Returns 0 on success, or the error from 966 * bio_endio() on failure. 967 * 968 * WARNING: Unlike to how submit_bio() is usually used, this function does not 969 * result in bio reference to be consumed. The caller must drop the reference 970 * on his own. 971 */ 972 int submit_bio_wait(struct bio *bio) 973 { 974 DECLARE_COMPLETION_ONSTACK_MAP(done, bio->bi_disk->lockdep_map); 975 976 bio->bi_private = &done; 977 bio->bi_end_io = submit_bio_wait_endio; 978 bio->bi_opf |= REQ_SYNC; 979 submit_bio(bio); 980 wait_for_completion_io(&done); 981 982 return blk_status_to_errno(bio->bi_status); 983 } 984 EXPORT_SYMBOL(submit_bio_wait); 985 986 /** 987 * bio_advance - increment/complete a bio by some number of bytes 988 * @bio: bio to advance 989 * @bytes: number of bytes to complete 990 * 991 * This updates bi_sector, bi_size and bi_idx; if the number of bytes to 992 * complete doesn't align with a bvec boundary, then bv_len and bv_offset will 993 * be updated on the last bvec as well. 994 * 995 * @bio will then represent the remaining, uncompleted portion of the io. 996 */ 997 void bio_advance(struct bio *bio, unsigned bytes) 998 { 999 if (bio_integrity(bio)) 1000 bio_integrity_advance(bio, bytes); 1001 1002 bio_advance_iter(bio, &bio->bi_iter, bytes); 1003 } 1004 EXPORT_SYMBOL(bio_advance); 1005 1006 void bio_copy_data_iter(struct bio *dst, struct bvec_iter *dst_iter, 1007 struct bio *src, struct bvec_iter *src_iter) 1008 { 1009 struct bio_vec src_bv, dst_bv; 1010 void *src_p, *dst_p; 1011 unsigned bytes; 1012 1013 while (src_iter->bi_size && dst_iter->bi_size) { 1014 src_bv = bio_iter_iovec(src, *src_iter); 1015 dst_bv = bio_iter_iovec(dst, *dst_iter); 1016 1017 bytes = min(src_bv.bv_len, dst_bv.bv_len); 1018 1019 src_p = kmap_atomic(src_bv.bv_page); 1020 dst_p = kmap_atomic(dst_bv.bv_page); 1021 1022 memcpy(dst_p + dst_bv.bv_offset, 1023 src_p + src_bv.bv_offset, 1024 bytes); 1025 1026 kunmap_atomic(dst_p); 1027 kunmap_atomic(src_p); 1028 1029 flush_dcache_page(dst_bv.bv_page); 1030 1031 bio_advance_iter(src, src_iter, bytes); 1032 bio_advance_iter(dst, dst_iter, bytes); 1033 } 1034 } 1035 EXPORT_SYMBOL(bio_copy_data_iter); 1036 1037 /** 1038 * bio_copy_data - copy contents of data buffers from one bio to another 1039 * @src: source bio 1040 * @dst: destination bio 1041 * 1042 * Stops when it reaches the end of either @src or @dst - that is, copies 1043 * min(src->bi_size, dst->bi_size) bytes (or the equivalent for lists of bios). 1044 */ 1045 void bio_copy_data(struct bio *dst, struct bio *src) 1046 { 1047 struct bvec_iter src_iter = src->bi_iter; 1048 struct bvec_iter dst_iter = dst->bi_iter; 1049 1050 bio_copy_data_iter(dst, &dst_iter, src, &src_iter); 1051 } 1052 EXPORT_SYMBOL(bio_copy_data); 1053 1054 /** 1055 * bio_list_copy_data - copy contents of data buffers from one chain of bios to 1056 * another 1057 * @src: source bio list 1058 * @dst: destination bio list 1059 * 1060 * Stops when it reaches the end of either the @src list or @dst list - that is, 1061 * copies min(src->bi_size, dst->bi_size) bytes (or the equivalent for lists of 1062 * bios). 1063 */ 1064 void bio_list_copy_data(struct bio *dst, struct bio *src) 1065 { 1066 struct bvec_iter src_iter = src->bi_iter; 1067 struct bvec_iter dst_iter = dst->bi_iter; 1068 1069 while (1) { 1070 if (!src_iter.bi_size) { 1071 src = src->bi_next; 1072 if (!src) 1073 break; 1074 1075 src_iter = src->bi_iter; 1076 } 1077 1078 if (!dst_iter.bi_size) { 1079 dst = dst->bi_next; 1080 if (!dst) 1081 break; 1082 1083 dst_iter = dst->bi_iter; 1084 } 1085 1086 bio_copy_data_iter(dst, &dst_iter, src, &src_iter); 1087 } 1088 } 1089 EXPORT_SYMBOL(bio_list_copy_data); 1090 1091 struct bio_map_data { 1092 int is_our_pages; 1093 struct iov_iter iter; 1094 struct iovec iov[]; 1095 }; 1096 1097 static struct bio_map_data *bio_alloc_map_data(struct iov_iter *data, 1098 gfp_t gfp_mask) 1099 { 1100 struct bio_map_data *bmd; 1101 if (data->nr_segs > UIO_MAXIOV) 1102 return NULL; 1103 1104 bmd = kmalloc(sizeof(struct bio_map_data) + 1105 sizeof(struct iovec) * data->nr_segs, gfp_mask); 1106 if (!bmd) 1107 return NULL; 1108 memcpy(bmd->iov, data->iov, sizeof(struct iovec) * data->nr_segs); 1109 bmd->iter = *data; 1110 bmd->iter.iov = bmd->iov; 1111 return bmd; 1112 } 1113 1114 /** 1115 * bio_copy_from_iter - copy all pages from iov_iter to bio 1116 * @bio: The &struct bio which describes the I/O as destination 1117 * @iter: iov_iter as source 1118 * 1119 * Copy all pages from iov_iter to bio. 1120 * Returns 0 on success, or error on failure. 1121 */ 1122 static int bio_copy_from_iter(struct bio *bio, struct iov_iter *iter) 1123 { 1124 int i; 1125 struct bio_vec *bvec; 1126 1127 bio_for_each_segment_all(bvec, bio, i) { 1128 ssize_t ret; 1129 1130 ret = copy_page_from_iter(bvec->bv_page, 1131 bvec->bv_offset, 1132 bvec->bv_len, 1133 iter); 1134 1135 if (!iov_iter_count(iter)) 1136 break; 1137 1138 if (ret < bvec->bv_len) 1139 return -EFAULT; 1140 } 1141 1142 return 0; 1143 } 1144 1145 /** 1146 * bio_copy_to_iter - copy all pages from bio to iov_iter 1147 * @bio: The &struct bio which describes the I/O as source 1148 * @iter: iov_iter as destination 1149 * 1150 * Copy all pages from bio to iov_iter. 1151 * Returns 0 on success, or error on failure. 1152 */ 1153 static int bio_copy_to_iter(struct bio *bio, struct iov_iter iter) 1154 { 1155 int i; 1156 struct bio_vec *bvec; 1157 1158 bio_for_each_segment_all(bvec, bio, i) { 1159 ssize_t ret; 1160 1161 ret = copy_page_to_iter(bvec->bv_page, 1162 bvec->bv_offset, 1163 bvec->bv_len, 1164 &iter); 1165 1166 if (!iov_iter_count(&iter)) 1167 break; 1168 1169 if (ret < bvec->bv_len) 1170 return -EFAULT; 1171 } 1172 1173 return 0; 1174 } 1175 1176 void bio_free_pages(struct bio *bio) 1177 { 1178 struct bio_vec *bvec; 1179 int i; 1180 1181 bio_for_each_segment_all(bvec, bio, i) 1182 __free_page(bvec->bv_page); 1183 } 1184 EXPORT_SYMBOL(bio_free_pages); 1185 1186 /** 1187 * bio_uncopy_user - finish previously mapped bio 1188 * @bio: bio being terminated 1189 * 1190 * Free pages allocated from bio_copy_user_iov() and write back data 1191 * to user space in case of a read. 1192 */ 1193 int bio_uncopy_user(struct bio *bio) 1194 { 1195 struct bio_map_data *bmd = bio->bi_private; 1196 int ret = 0; 1197 1198 if (!bio_flagged(bio, BIO_NULL_MAPPED)) { 1199 /* 1200 * if we're in a workqueue, the request is orphaned, so 1201 * don't copy into a random user address space, just free 1202 * and return -EINTR so user space doesn't expect any data. 1203 */ 1204 if (!current->mm) 1205 ret = -EINTR; 1206 else if (bio_data_dir(bio) == READ) 1207 ret = bio_copy_to_iter(bio, bmd->iter); 1208 if (bmd->is_our_pages) 1209 bio_free_pages(bio); 1210 } 1211 kfree(bmd); 1212 bio_put(bio); 1213 return ret; 1214 } 1215 1216 /** 1217 * bio_copy_user_iov - copy user data to bio 1218 * @q: destination block queue 1219 * @map_data: pointer to the rq_map_data holding pages (if necessary) 1220 * @iter: iovec iterator 1221 * @gfp_mask: memory allocation flags 1222 * 1223 * Prepares and returns a bio for indirect user io, bouncing data 1224 * to/from kernel pages as necessary. Must be paired with 1225 * call bio_uncopy_user() on io completion. 1226 */ 1227 struct bio *bio_copy_user_iov(struct request_queue *q, 1228 struct rq_map_data *map_data, 1229 struct iov_iter *iter, 1230 gfp_t gfp_mask) 1231 { 1232 struct bio_map_data *bmd; 1233 struct page *page; 1234 struct bio *bio; 1235 int i = 0, ret; 1236 int nr_pages; 1237 unsigned int len = iter->count; 1238 unsigned int offset = map_data ? offset_in_page(map_data->offset) : 0; 1239 1240 bmd = bio_alloc_map_data(iter, gfp_mask); 1241 if (!bmd) 1242 return ERR_PTR(-ENOMEM); 1243 1244 /* 1245 * We need to do a deep copy of the iov_iter including the iovecs. 1246 * The caller provided iov might point to an on-stack or otherwise 1247 * shortlived one. 1248 */ 1249 bmd->is_our_pages = map_data ? 0 : 1; 1250 1251 nr_pages = DIV_ROUND_UP(offset + len, PAGE_SIZE); 1252 if (nr_pages > BIO_MAX_PAGES) 1253 nr_pages = BIO_MAX_PAGES; 1254 1255 ret = -ENOMEM; 1256 bio = bio_kmalloc(gfp_mask, nr_pages); 1257 if (!bio) 1258 goto out_bmd; 1259 1260 ret = 0; 1261 1262 if (map_data) { 1263 nr_pages = 1 << map_data->page_order; 1264 i = map_data->offset / PAGE_SIZE; 1265 } 1266 while (len) { 1267 unsigned int bytes = PAGE_SIZE; 1268 1269 bytes -= offset; 1270 1271 if (bytes > len) 1272 bytes = len; 1273 1274 if (map_data) { 1275 if (i == map_data->nr_entries * nr_pages) { 1276 ret = -ENOMEM; 1277 break; 1278 } 1279 1280 page = map_data->pages[i / nr_pages]; 1281 page += (i % nr_pages); 1282 1283 i++; 1284 } else { 1285 page = alloc_page(q->bounce_gfp | gfp_mask); 1286 if (!page) { 1287 ret = -ENOMEM; 1288 break; 1289 } 1290 } 1291 1292 if (bio_add_pc_page(q, bio, page, bytes, offset) < bytes) 1293 break; 1294 1295 len -= bytes; 1296 offset = 0; 1297 } 1298 1299 if (ret) 1300 goto cleanup; 1301 1302 if (map_data) 1303 map_data->offset += bio->bi_iter.bi_size; 1304 1305 /* 1306 * success 1307 */ 1308 if (((iter->type & WRITE) && (!map_data || !map_data->null_mapped)) || 1309 (map_data && map_data->from_user)) { 1310 ret = bio_copy_from_iter(bio, iter); 1311 if (ret) 1312 goto cleanup; 1313 } else { 1314 iov_iter_advance(iter, bio->bi_iter.bi_size); 1315 } 1316 1317 bio->bi_private = bmd; 1318 if (map_data && map_data->null_mapped) 1319 bio_set_flag(bio, BIO_NULL_MAPPED); 1320 return bio; 1321 cleanup: 1322 if (!map_data) 1323 bio_free_pages(bio); 1324 bio_put(bio); 1325 out_bmd: 1326 kfree(bmd); 1327 return ERR_PTR(ret); 1328 } 1329 1330 /** 1331 * bio_map_user_iov - map user iovec into bio 1332 * @q: the struct request_queue for the bio 1333 * @iter: iovec iterator 1334 * @gfp_mask: memory allocation flags 1335 * 1336 * Map the user space address into a bio suitable for io to a block 1337 * device. Returns an error pointer in case of error. 1338 */ 1339 struct bio *bio_map_user_iov(struct request_queue *q, 1340 struct iov_iter *iter, 1341 gfp_t gfp_mask) 1342 { 1343 int j; 1344 struct bio *bio; 1345 int ret; 1346 struct bio_vec *bvec; 1347 1348 if (!iov_iter_count(iter)) 1349 return ERR_PTR(-EINVAL); 1350 1351 bio = bio_kmalloc(gfp_mask, iov_iter_npages(iter, BIO_MAX_PAGES)); 1352 if (!bio) 1353 return ERR_PTR(-ENOMEM); 1354 1355 while (iov_iter_count(iter)) { 1356 struct page **pages; 1357 ssize_t bytes; 1358 size_t offs, added = 0; 1359 int npages; 1360 1361 bytes = iov_iter_get_pages_alloc(iter, &pages, LONG_MAX, &offs); 1362 if (unlikely(bytes <= 0)) { 1363 ret = bytes ? bytes : -EFAULT; 1364 goto out_unmap; 1365 } 1366 1367 npages = DIV_ROUND_UP(offs + bytes, PAGE_SIZE); 1368 1369 if (unlikely(offs & queue_dma_alignment(q))) { 1370 ret = -EINVAL; 1371 j = 0; 1372 } else { 1373 for (j = 0; j < npages; j++) { 1374 struct page *page = pages[j]; 1375 unsigned int n = PAGE_SIZE - offs; 1376 unsigned short prev_bi_vcnt = bio->bi_vcnt; 1377 1378 if (n > bytes) 1379 n = bytes; 1380 1381 if (!bio_add_pc_page(q, bio, page, n, offs)) 1382 break; 1383 1384 /* 1385 * check if vector was merged with previous 1386 * drop page reference if needed 1387 */ 1388 if (bio->bi_vcnt == prev_bi_vcnt) 1389 put_page(page); 1390 1391 added += n; 1392 bytes -= n; 1393 offs = 0; 1394 } 1395 iov_iter_advance(iter, added); 1396 } 1397 /* 1398 * release the pages we didn't map into the bio, if any 1399 */ 1400 while (j < npages) 1401 put_page(pages[j++]); 1402 kvfree(pages); 1403 /* couldn't stuff something into bio? */ 1404 if (bytes) 1405 break; 1406 } 1407 1408 bio_set_flag(bio, BIO_USER_MAPPED); 1409 1410 /* 1411 * subtle -- if bio_map_user_iov() ended up bouncing a bio, 1412 * it would normally disappear when its bi_end_io is run. 1413 * however, we need it for the unmap, so grab an extra 1414 * reference to it 1415 */ 1416 bio_get(bio); 1417 return bio; 1418 1419 out_unmap: 1420 bio_for_each_segment_all(bvec, bio, j) { 1421 put_page(bvec->bv_page); 1422 } 1423 bio_put(bio); 1424 return ERR_PTR(ret); 1425 } 1426 1427 static void __bio_unmap_user(struct bio *bio) 1428 { 1429 struct bio_vec *bvec; 1430 int i; 1431 1432 /* 1433 * make sure we dirty pages we wrote to 1434 */ 1435 bio_for_each_segment_all(bvec, bio, i) { 1436 if (bio_data_dir(bio) == READ) 1437 set_page_dirty_lock(bvec->bv_page); 1438 1439 put_page(bvec->bv_page); 1440 } 1441 1442 bio_put(bio); 1443 } 1444 1445 /** 1446 * bio_unmap_user - unmap a bio 1447 * @bio: the bio being unmapped 1448 * 1449 * Unmap a bio previously mapped by bio_map_user_iov(). Must be called from 1450 * process context. 1451 * 1452 * bio_unmap_user() may sleep. 1453 */ 1454 void bio_unmap_user(struct bio *bio) 1455 { 1456 __bio_unmap_user(bio); 1457 bio_put(bio); 1458 } 1459 1460 static void bio_map_kern_endio(struct bio *bio) 1461 { 1462 bio_put(bio); 1463 } 1464 1465 /** 1466 * bio_map_kern - map kernel address into bio 1467 * @q: the struct request_queue for the bio 1468 * @data: pointer to buffer to map 1469 * @len: length in bytes 1470 * @gfp_mask: allocation flags for bio allocation 1471 * 1472 * Map the kernel address into a bio suitable for io to a block 1473 * device. Returns an error pointer in case of error. 1474 */ 1475 struct bio *bio_map_kern(struct request_queue *q, void *data, unsigned int len, 1476 gfp_t gfp_mask) 1477 { 1478 unsigned long kaddr = (unsigned long)data; 1479 unsigned long end = (kaddr + len + PAGE_SIZE - 1) >> PAGE_SHIFT; 1480 unsigned long start = kaddr >> PAGE_SHIFT; 1481 const int nr_pages = end - start; 1482 int offset, i; 1483 struct bio *bio; 1484 1485 bio = bio_kmalloc(gfp_mask, nr_pages); 1486 if (!bio) 1487 return ERR_PTR(-ENOMEM); 1488 1489 offset = offset_in_page(kaddr); 1490 for (i = 0; i < nr_pages; i++) { 1491 unsigned int bytes = PAGE_SIZE - offset; 1492 1493 if (len <= 0) 1494 break; 1495 1496 if (bytes > len) 1497 bytes = len; 1498 1499 if (bio_add_pc_page(q, bio, virt_to_page(data), bytes, 1500 offset) < bytes) { 1501 /* we don't support partial mappings */ 1502 bio_put(bio); 1503 return ERR_PTR(-EINVAL); 1504 } 1505 1506 data += bytes; 1507 len -= bytes; 1508 offset = 0; 1509 } 1510 1511 bio->bi_end_io = bio_map_kern_endio; 1512 return bio; 1513 } 1514 EXPORT_SYMBOL(bio_map_kern); 1515 1516 static void bio_copy_kern_endio(struct bio *bio) 1517 { 1518 bio_free_pages(bio); 1519 bio_put(bio); 1520 } 1521 1522 static void bio_copy_kern_endio_read(struct bio *bio) 1523 { 1524 char *p = bio->bi_private; 1525 struct bio_vec *bvec; 1526 int i; 1527 1528 bio_for_each_segment_all(bvec, bio, i) { 1529 memcpy(p, page_address(bvec->bv_page), bvec->bv_len); 1530 p += bvec->bv_len; 1531 } 1532 1533 bio_copy_kern_endio(bio); 1534 } 1535 1536 /** 1537 * bio_copy_kern - copy kernel address into bio 1538 * @q: the struct request_queue for the bio 1539 * @data: pointer to buffer to copy 1540 * @len: length in bytes 1541 * @gfp_mask: allocation flags for bio and page allocation 1542 * @reading: data direction is READ 1543 * 1544 * copy the kernel address into a bio suitable for io to a block 1545 * device. Returns an error pointer in case of error. 1546 */ 1547 struct bio *bio_copy_kern(struct request_queue *q, void *data, unsigned int len, 1548 gfp_t gfp_mask, int reading) 1549 { 1550 unsigned long kaddr = (unsigned long)data; 1551 unsigned long end = (kaddr + len + PAGE_SIZE - 1) >> PAGE_SHIFT; 1552 unsigned long start = kaddr >> PAGE_SHIFT; 1553 struct bio *bio; 1554 void *p = data; 1555 int nr_pages = 0; 1556 1557 /* 1558 * Overflow, abort 1559 */ 1560 if (end < start) 1561 return ERR_PTR(-EINVAL); 1562 1563 nr_pages = end - start; 1564 bio = bio_kmalloc(gfp_mask, nr_pages); 1565 if (!bio) 1566 return ERR_PTR(-ENOMEM); 1567 1568 while (len) { 1569 struct page *page; 1570 unsigned int bytes = PAGE_SIZE; 1571 1572 if (bytes > len) 1573 bytes = len; 1574 1575 page = alloc_page(q->bounce_gfp | gfp_mask); 1576 if (!page) 1577 goto cleanup; 1578 1579 if (!reading) 1580 memcpy(page_address(page), p, bytes); 1581 1582 if (bio_add_pc_page(q, bio, page, bytes, 0) < bytes) 1583 break; 1584 1585 len -= bytes; 1586 p += bytes; 1587 } 1588 1589 if (reading) { 1590 bio->bi_end_io = bio_copy_kern_endio_read; 1591 bio->bi_private = data; 1592 } else { 1593 bio->bi_end_io = bio_copy_kern_endio; 1594 } 1595 1596 return bio; 1597 1598 cleanup: 1599 bio_free_pages(bio); 1600 bio_put(bio); 1601 return ERR_PTR(-ENOMEM); 1602 } 1603 1604 /* 1605 * bio_set_pages_dirty() and bio_check_pages_dirty() are support functions 1606 * for performing direct-IO in BIOs. 1607 * 1608 * The problem is that we cannot run set_page_dirty() from interrupt context 1609 * because the required locks are not interrupt-safe. So what we can do is to 1610 * mark the pages dirty _before_ performing IO. And in interrupt context, 1611 * check that the pages are still dirty. If so, fine. If not, redirty them 1612 * in process context. 1613 * 1614 * We special-case compound pages here: normally this means reads into hugetlb 1615 * pages. The logic in here doesn't really work right for compound pages 1616 * because the VM does not uniformly chase down the head page in all cases. 1617 * But dirtiness of compound pages is pretty meaningless anyway: the VM doesn't 1618 * handle them at all. So we skip compound pages here at an early stage. 1619 * 1620 * Note that this code is very hard to test under normal circumstances because 1621 * direct-io pins the pages with get_user_pages(). This makes 1622 * is_page_cache_freeable return false, and the VM will not clean the pages. 1623 * But other code (eg, flusher threads) could clean the pages if they are mapped 1624 * pagecache. 1625 * 1626 * Simply disabling the call to bio_set_pages_dirty() is a good way to test the 1627 * deferred bio dirtying paths. 1628 */ 1629 1630 /* 1631 * bio_set_pages_dirty() will mark all the bio's pages as dirty. 1632 */ 1633 void bio_set_pages_dirty(struct bio *bio) 1634 { 1635 struct bio_vec *bvec; 1636 int i; 1637 1638 bio_for_each_segment_all(bvec, bio, i) { 1639 struct page *page = bvec->bv_page; 1640 1641 if (page && !PageCompound(page)) 1642 set_page_dirty_lock(page); 1643 } 1644 } 1645 EXPORT_SYMBOL_GPL(bio_set_pages_dirty); 1646 1647 static void bio_release_pages(struct bio *bio) 1648 { 1649 struct bio_vec *bvec; 1650 int i; 1651 1652 bio_for_each_segment_all(bvec, bio, i) { 1653 struct page *page = bvec->bv_page; 1654 1655 if (page) 1656 put_page(page); 1657 } 1658 } 1659 1660 /* 1661 * bio_check_pages_dirty() will check that all the BIO's pages are still dirty. 1662 * If they are, then fine. If, however, some pages are clean then they must 1663 * have been written out during the direct-IO read. So we take another ref on 1664 * the BIO and the offending pages and re-dirty the pages in process context. 1665 * 1666 * It is expected that bio_check_pages_dirty() will wholly own the BIO from 1667 * here on. It will run one put_page() against each page and will run one 1668 * bio_put() against the BIO. 1669 */ 1670 1671 static void bio_dirty_fn(struct work_struct *work); 1672 1673 static DECLARE_WORK(bio_dirty_work, bio_dirty_fn); 1674 static DEFINE_SPINLOCK(bio_dirty_lock); 1675 static struct bio *bio_dirty_list; 1676 1677 /* 1678 * This runs in process context 1679 */ 1680 static void bio_dirty_fn(struct work_struct *work) 1681 { 1682 unsigned long flags; 1683 struct bio *bio; 1684 1685 spin_lock_irqsave(&bio_dirty_lock, flags); 1686 bio = bio_dirty_list; 1687 bio_dirty_list = NULL; 1688 spin_unlock_irqrestore(&bio_dirty_lock, flags); 1689 1690 while (bio) { 1691 struct bio *next = bio->bi_private; 1692 1693 bio_set_pages_dirty(bio); 1694 bio_release_pages(bio); 1695 bio_put(bio); 1696 bio = next; 1697 } 1698 } 1699 1700 void bio_check_pages_dirty(struct bio *bio) 1701 { 1702 struct bio_vec *bvec; 1703 int nr_clean_pages = 0; 1704 int i; 1705 1706 bio_for_each_segment_all(bvec, bio, i) { 1707 struct page *page = bvec->bv_page; 1708 1709 if (PageDirty(page) || PageCompound(page)) { 1710 put_page(page); 1711 bvec->bv_page = NULL; 1712 } else { 1713 nr_clean_pages++; 1714 } 1715 } 1716 1717 if (nr_clean_pages) { 1718 unsigned long flags; 1719 1720 spin_lock_irqsave(&bio_dirty_lock, flags); 1721 bio->bi_private = bio_dirty_list; 1722 bio_dirty_list = bio; 1723 spin_unlock_irqrestore(&bio_dirty_lock, flags); 1724 schedule_work(&bio_dirty_work); 1725 } else { 1726 bio_put(bio); 1727 } 1728 } 1729 EXPORT_SYMBOL_GPL(bio_check_pages_dirty); 1730 1731 void generic_start_io_acct(struct request_queue *q, int op, 1732 unsigned long sectors, struct hd_struct *part) 1733 { 1734 const int sgrp = op_stat_group(op); 1735 int cpu = part_stat_lock(); 1736 1737 part_round_stats(q, cpu, part); 1738 part_stat_inc(cpu, part, ios[sgrp]); 1739 part_stat_add(cpu, part, sectors[sgrp], sectors); 1740 part_inc_in_flight(q, part, op_is_write(op)); 1741 1742 part_stat_unlock(); 1743 } 1744 EXPORT_SYMBOL(generic_start_io_acct); 1745 1746 void generic_end_io_acct(struct request_queue *q, int req_op, 1747 struct hd_struct *part, unsigned long start_time) 1748 { 1749 unsigned long duration = jiffies - start_time; 1750 const int sgrp = op_stat_group(req_op); 1751 int cpu = part_stat_lock(); 1752 1753 part_stat_add(cpu, part, ticks[sgrp], duration); 1754 part_round_stats(q, cpu, part); 1755 part_dec_in_flight(q, part, op_is_write(req_op)); 1756 1757 part_stat_unlock(); 1758 } 1759 EXPORT_SYMBOL(generic_end_io_acct); 1760 1761 #if ARCH_IMPLEMENTS_FLUSH_DCACHE_PAGE 1762 void bio_flush_dcache_pages(struct bio *bi) 1763 { 1764 struct bio_vec bvec; 1765 struct bvec_iter iter; 1766 1767 bio_for_each_segment(bvec, bi, iter) 1768 flush_dcache_page(bvec.bv_page); 1769 } 1770 EXPORT_SYMBOL(bio_flush_dcache_pages); 1771 #endif 1772 1773 static inline bool bio_remaining_done(struct bio *bio) 1774 { 1775 /* 1776 * If we're not chaining, then ->__bi_remaining is always 1 and 1777 * we always end io on the first invocation. 1778 */ 1779 if (!bio_flagged(bio, BIO_CHAIN)) 1780 return true; 1781 1782 BUG_ON(atomic_read(&bio->__bi_remaining) <= 0); 1783 1784 if (atomic_dec_and_test(&bio->__bi_remaining)) { 1785 bio_clear_flag(bio, BIO_CHAIN); 1786 return true; 1787 } 1788 1789 return false; 1790 } 1791 1792 /** 1793 * bio_endio - end I/O on a bio 1794 * @bio: bio 1795 * 1796 * Description: 1797 * bio_endio() will end I/O on the whole bio. bio_endio() is the preferred 1798 * way to end I/O on a bio. No one should call bi_end_io() directly on a 1799 * bio unless they own it and thus know that it has an end_io function. 1800 * 1801 * bio_endio() can be called several times on a bio that has been chained 1802 * using bio_chain(). The ->bi_end_io() function will only be called the 1803 * last time. At this point the BLK_TA_COMPLETE tracing event will be 1804 * generated if BIO_TRACE_COMPLETION is set. 1805 **/ 1806 void bio_endio(struct bio *bio) 1807 { 1808 again: 1809 if (!bio_remaining_done(bio)) 1810 return; 1811 if (!bio_integrity_endio(bio)) 1812 return; 1813 1814 if (bio->bi_disk) 1815 rq_qos_done_bio(bio->bi_disk->queue, bio); 1816 1817 /* 1818 * Need to have a real endio function for chained bios, otherwise 1819 * various corner cases will break (like stacking block devices that 1820 * save/restore bi_end_io) - however, we want to avoid unbounded 1821 * recursion and blowing the stack. Tail call optimization would 1822 * handle this, but compiling with frame pointers also disables 1823 * gcc's sibling call optimization. 1824 */ 1825 if (bio->bi_end_io == bio_chain_endio) { 1826 bio = __bio_chain_endio(bio); 1827 goto again; 1828 } 1829 1830 if (bio->bi_disk && bio_flagged(bio, BIO_TRACE_COMPLETION)) { 1831 trace_block_bio_complete(bio->bi_disk->queue, bio, 1832 blk_status_to_errno(bio->bi_status)); 1833 bio_clear_flag(bio, BIO_TRACE_COMPLETION); 1834 } 1835 1836 blk_throtl_bio_endio(bio); 1837 /* release cgroup info */ 1838 bio_uninit(bio); 1839 if (bio->bi_end_io) 1840 bio->bi_end_io(bio); 1841 } 1842 EXPORT_SYMBOL(bio_endio); 1843 1844 /** 1845 * bio_split - split a bio 1846 * @bio: bio to split 1847 * @sectors: number of sectors to split from the front of @bio 1848 * @gfp: gfp mask 1849 * @bs: bio set to allocate from 1850 * 1851 * Allocates and returns a new bio which represents @sectors from the start of 1852 * @bio, and updates @bio to represent the remaining sectors. 1853 * 1854 * Unless this is a discard request the newly allocated bio will point 1855 * to @bio's bi_io_vec; it is the caller's responsibility to ensure that 1856 * @bio is not freed before the split. 1857 */ 1858 struct bio *bio_split(struct bio *bio, int sectors, 1859 gfp_t gfp, struct bio_set *bs) 1860 { 1861 struct bio *split; 1862 1863 BUG_ON(sectors <= 0); 1864 BUG_ON(sectors >= bio_sectors(bio)); 1865 1866 split = bio_clone_fast(bio, gfp, bs); 1867 if (!split) 1868 return NULL; 1869 1870 split->bi_iter.bi_size = sectors << 9; 1871 1872 if (bio_integrity(split)) 1873 bio_integrity_trim(split); 1874 1875 bio_advance(bio, split->bi_iter.bi_size); 1876 1877 if (bio_flagged(bio, BIO_TRACE_COMPLETION)) 1878 bio_set_flag(split, BIO_TRACE_COMPLETION); 1879 1880 return split; 1881 } 1882 EXPORT_SYMBOL(bio_split); 1883 1884 /** 1885 * bio_trim - trim a bio 1886 * @bio: bio to trim 1887 * @offset: number of sectors to trim from the front of @bio 1888 * @size: size we want to trim @bio to, in sectors 1889 */ 1890 void bio_trim(struct bio *bio, int offset, int size) 1891 { 1892 /* 'bio' is a cloned bio which we need to trim to match 1893 * the given offset and size. 1894 */ 1895 1896 size <<= 9; 1897 if (offset == 0 && size == bio->bi_iter.bi_size) 1898 return; 1899 1900 bio_clear_flag(bio, BIO_SEG_VALID); 1901 1902 bio_advance(bio, offset << 9); 1903 1904 bio->bi_iter.bi_size = size; 1905 1906 if (bio_integrity(bio)) 1907 bio_integrity_trim(bio); 1908 1909 } 1910 EXPORT_SYMBOL_GPL(bio_trim); 1911 1912 /* 1913 * create memory pools for biovec's in a bio_set. 1914 * use the global biovec slabs created for general use. 1915 */ 1916 int biovec_init_pool(mempool_t *pool, int pool_entries) 1917 { 1918 struct biovec_slab *bp = bvec_slabs + BVEC_POOL_MAX; 1919 1920 return mempool_init_slab_pool(pool, pool_entries, bp->slab); 1921 } 1922 1923 /* 1924 * bioset_exit - exit a bioset initialized with bioset_init() 1925 * 1926 * May be called on a zeroed but uninitialized bioset (i.e. allocated with 1927 * kzalloc()). 1928 */ 1929 void bioset_exit(struct bio_set *bs) 1930 { 1931 if (bs->rescue_workqueue) 1932 destroy_workqueue(bs->rescue_workqueue); 1933 bs->rescue_workqueue = NULL; 1934 1935 mempool_exit(&bs->bio_pool); 1936 mempool_exit(&bs->bvec_pool); 1937 1938 bioset_integrity_free(bs); 1939 if (bs->bio_slab) 1940 bio_put_slab(bs); 1941 bs->bio_slab = NULL; 1942 } 1943 EXPORT_SYMBOL(bioset_exit); 1944 1945 /** 1946 * bioset_init - Initialize a bio_set 1947 * @bs: pool to initialize 1948 * @pool_size: Number of bio and bio_vecs to cache in the mempool 1949 * @front_pad: Number of bytes to allocate in front of the returned bio 1950 * @flags: Flags to modify behavior, currently %BIOSET_NEED_BVECS 1951 * and %BIOSET_NEED_RESCUER 1952 * 1953 * Description: 1954 * Set up a bio_set to be used with @bio_alloc_bioset. Allows the caller 1955 * to ask for a number of bytes to be allocated in front of the bio. 1956 * Front pad allocation is useful for embedding the bio inside 1957 * another structure, to avoid allocating extra data to go with the bio. 1958 * Note that the bio must be embedded at the END of that structure always, 1959 * or things will break badly. 1960 * If %BIOSET_NEED_BVECS is set in @flags, a separate pool will be allocated 1961 * for allocating iovecs. This pool is not needed e.g. for bio_clone_fast(). 1962 * If %BIOSET_NEED_RESCUER is set, a workqueue is created which can be used to 1963 * dispatch queued requests when the mempool runs out of space. 1964 * 1965 */ 1966 int bioset_init(struct bio_set *bs, 1967 unsigned int pool_size, 1968 unsigned int front_pad, 1969 int flags) 1970 { 1971 unsigned int back_pad = BIO_INLINE_VECS * sizeof(struct bio_vec); 1972 1973 bs->front_pad = front_pad; 1974 1975 spin_lock_init(&bs->rescue_lock); 1976 bio_list_init(&bs->rescue_list); 1977 INIT_WORK(&bs->rescue_work, bio_alloc_rescue); 1978 1979 bs->bio_slab = bio_find_or_create_slab(front_pad + back_pad); 1980 if (!bs->bio_slab) 1981 return -ENOMEM; 1982 1983 if (mempool_init_slab_pool(&bs->bio_pool, pool_size, bs->bio_slab)) 1984 goto bad; 1985 1986 if ((flags & BIOSET_NEED_BVECS) && 1987 biovec_init_pool(&bs->bvec_pool, pool_size)) 1988 goto bad; 1989 1990 if (!(flags & BIOSET_NEED_RESCUER)) 1991 return 0; 1992 1993 bs->rescue_workqueue = alloc_workqueue("bioset", WQ_MEM_RECLAIM, 0); 1994 if (!bs->rescue_workqueue) 1995 goto bad; 1996 1997 return 0; 1998 bad: 1999 bioset_exit(bs); 2000 return -ENOMEM; 2001 } 2002 EXPORT_SYMBOL(bioset_init); 2003 2004 /* 2005 * Initialize and setup a new bio_set, based on the settings from 2006 * another bio_set. 2007 */ 2008 int bioset_init_from_src(struct bio_set *bs, struct bio_set *src) 2009 { 2010 int flags; 2011 2012 flags = 0; 2013 if (src->bvec_pool.min_nr) 2014 flags |= BIOSET_NEED_BVECS; 2015 if (src->rescue_workqueue) 2016 flags |= BIOSET_NEED_RESCUER; 2017 2018 return bioset_init(bs, src->bio_pool.min_nr, src->front_pad, flags); 2019 } 2020 EXPORT_SYMBOL(bioset_init_from_src); 2021 2022 #ifdef CONFIG_BLK_CGROUP 2023 2024 #ifdef CONFIG_MEMCG 2025 /** 2026 * bio_associate_blkcg_from_page - associate a bio with the page's blkcg 2027 * @bio: target bio 2028 * @page: the page to lookup the blkcg from 2029 * 2030 * Associate @bio with the blkcg from @page's owning memcg. This works like 2031 * every other associate function wrt references. 2032 */ 2033 int bio_associate_blkcg_from_page(struct bio *bio, struct page *page) 2034 { 2035 struct cgroup_subsys_state *blkcg_css; 2036 2037 if (unlikely(bio->bi_css)) 2038 return -EBUSY; 2039 if (!page->mem_cgroup) 2040 return 0; 2041 blkcg_css = cgroup_get_e_css(page->mem_cgroup->css.cgroup, 2042 &io_cgrp_subsys); 2043 bio->bi_css = blkcg_css; 2044 return 0; 2045 } 2046 #endif /* CONFIG_MEMCG */ 2047 2048 /** 2049 * bio_associate_blkcg - associate a bio with the specified blkcg 2050 * @bio: target bio 2051 * @blkcg_css: css of the blkcg to associate 2052 * 2053 * Associate @bio with the blkcg specified by @blkcg_css. Block layer will 2054 * treat @bio as if it were issued by a task which belongs to the blkcg. 2055 * 2056 * This function takes an extra reference of @blkcg_css which will be put 2057 * when @bio is released. The caller must own @bio and is responsible for 2058 * synchronizing calls to this function. 2059 */ 2060 int bio_associate_blkcg(struct bio *bio, struct cgroup_subsys_state *blkcg_css) 2061 { 2062 if (unlikely(bio->bi_css)) 2063 return -EBUSY; 2064 css_get(blkcg_css); 2065 bio->bi_css = blkcg_css; 2066 return 0; 2067 } 2068 EXPORT_SYMBOL_GPL(bio_associate_blkcg); 2069 2070 /** 2071 * bio_associate_blkg - associate a bio with the specified blkg 2072 * @bio: target bio 2073 * @blkg: the blkg to associate 2074 * 2075 * Associate @bio with the blkg specified by @blkg. This is the queue specific 2076 * blkcg information associated with the @bio, a reference will be taken on the 2077 * @blkg and will be freed when the bio is freed. 2078 */ 2079 int bio_associate_blkg(struct bio *bio, struct blkcg_gq *blkg) 2080 { 2081 if (unlikely(bio->bi_blkg)) 2082 return -EBUSY; 2083 blkg_get(blkg); 2084 bio->bi_blkg = blkg; 2085 return 0; 2086 } 2087 2088 /** 2089 * bio_disassociate_task - undo bio_associate_current() 2090 * @bio: target bio 2091 */ 2092 void bio_disassociate_task(struct bio *bio) 2093 { 2094 if (bio->bi_ioc) { 2095 put_io_context(bio->bi_ioc); 2096 bio->bi_ioc = NULL; 2097 } 2098 if (bio->bi_css) { 2099 css_put(bio->bi_css); 2100 bio->bi_css = NULL; 2101 } 2102 if (bio->bi_blkg) { 2103 blkg_put(bio->bi_blkg); 2104 bio->bi_blkg = NULL; 2105 } 2106 } 2107 2108 /** 2109 * bio_clone_blkcg_association - clone blkcg association from src to dst bio 2110 * @dst: destination bio 2111 * @src: source bio 2112 */ 2113 void bio_clone_blkcg_association(struct bio *dst, struct bio *src) 2114 { 2115 if (src->bi_css) 2116 WARN_ON(bio_associate_blkcg(dst, src->bi_css)); 2117 } 2118 EXPORT_SYMBOL_GPL(bio_clone_blkcg_association); 2119 #endif /* CONFIG_BLK_CGROUP */ 2120 2121 static void __init biovec_init_slabs(void) 2122 { 2123 int i; 2124 2125 for (i = 0; i < BVEC_POOL_NR; i++) { 2126 int size; 2127 struct biovec_slab *bvs = bvec_slabs + i; 2128 2129 if (bvs->nr_vecs <= BIO_INLINE_VECS) { 2130 bvs->slab = NULL; 2131 continue; 2132 } 2133 2134 size = bvs->nr_vecs * sizeof(struct bio_vec); 2135 bvs->slab = kmem_cache_create(bvs->name, size, 0, 2136 SLAB_HWCACHE_ALIGN|SLAB_PANIC, NULL); 2137 } 2138 } 2139 2140 static int __init init_bio(void) 2141 { 2142 bio_slab_max = 2; 2143 bio_slab_nr = 0; 2144 bio_slabs = kcalloc(bio_slab_max, sizeof(struct bio_slab), 2145 GFP_KERNEL); 2146 if (!bio_slabs) 2147 panic("bio: can't allocate bios\n"); 2148 2149 bio_integrity_init(); 2150 biovec_init_slabs(); 2151 2152 if (bioset_init(&fs_bio_set, BIO_POOL_SIZE, 0, BIOSET_NEED_BVECS)) 2153 panic("bio: can't allocate bios\n"); 2154 2155 if (bioset_integrity_create(&fs_bio_set, BIO_POOL_SIZE)) 2156 panic("bio: can't create integrity pool\n"); 2157 2158 return 0; 2159 } 2160 subsys_initcall(init_bio); 2161