1913 lines · c
1// SPDX-License-Identifier: GPL-2.02/*3 * Copyright (C) 2001 Jens Axboe <axboe@kernel.dk>4 */5#include <linux/mm.h>6#include <linux/swap.h>7#include <linux/bio-integrity.h>8#include <linux/blkdev.h>9#include <linux/uio.h>10#include <linux/iocontext.h>11#include <linux/slab.h>12#include <linux/init.h>13#include <linux/kernel.h>14#include <linux/export.h>15#include <linux/mempool.h>16#include <linux/workqueue.h>17#include <linux/cgroup.h>18#include <linux/highmem.h>19#include <linux/blk-crypto.h>20#include <linux/xarray.h>21 22#include <trace/events/block.h>23#include "blk.h"24#include "blk-rq-qos.h"25#include "blk-cgroup.h"26 27#define ALLOC_CACHE_THRESHOLD 1628#define ALLOC_CACHE_MAX 25629 30struct bio_alloc_cache {31 struct bio *free_list;32 struct bio *free_list_irq;33 unsigned int nr;34 unsigned int nr_irq;35};36 37static struct biovec_slab {38 int nr_vecs;39 char *name;40 struct kmem_cache *slab;41} bvec_slabs[] __read_mostly = {42 { .nr_vecs = 16, .name = "biovec-16" },43 { .nr_vecs = 64, .name = "biovec-64" },44 { .nr_vecs = 128, .name = "biovec-128" },45 { .nr_vecs = BIO_MAX_VECS, .name = "biovec-max" },46};47 48static struct biovec_slab *biovec_slab(unsigned short nr_vecs)49{50 switch (nr_vecs) {51 /* smaller bios use inline vecs */52 case 5 ... 16:53 return &bvec_slabs[0];54 case 17 ... 64:55 return &bvec_slabs[1];56 case 65 ... 128:57 return &bvec_slabs[2];58 case 129 ... BIO_MAX_VECS:59 return &bvec_slabs[3];60 default:61 BUG();62 return NULL;63 }64}65 66/*67 * fs_bio_set is the bio_set containing bio and iovec memory pools used by68 * IO code that does not need private memory pools.69 */70struct bio_set fs_bio_set;71EXPORT_SYMBOL(fs_bio_set);72 73/*74 * Our slab pool management75 */76struct bio_slab {77 struct kmem_cache *slab;78 unsigned int slab_ref;79 unsigned int slab_size;80 char name[8];81};82static DEFINE_MUTEX(bio_slab_lock);83static DEFINE_XARRAY(bio_slabs);84 85static struct bio_slab *create_bio_slab(unsigned int size)86{87 struct bio_slab *bslab = kzalloc(sizeof(*bslab), GFP_KERNEL);88 89 if (!bslab)90 return NULL;91 92 snprintf(bslab->name, sizeof(bslab->name), "bio-%d", size);93 bslab->slab = kmem_cache_create(bslab->name, size,94 ARCH_KMALLOC_MINALIGN,95 SLAB_HWCACHE_ALIGN | SLAB_TYPESAFE_BY_RCU, NULL);96 if (!bslab->slab)97 goto fail_alloc_slab;98 99 bslab->slab_ref = 1;100 bslab->slab_size = size;101 102 if (!xa_err(xa_store(&bio_slabs, size, bslab, GFP_KERNEL)))103 return bslab;104 105 kmem_cache_destroy(bslab->slab);106 107fail_alloc_slab:108 kfree(bslab);109 return NULL;110}111 112static inline unsigned int bs_bio_slab_size(struct bio_set *bs)113{114 return bs->front_pad + sizeof(struct bio) + bs->back_pad;115}116 117static struct kmem_cache *bio_find_or_create_slab(struct bio_set *bs)118{119 unsigned int size = bs_bio_slab_size(bs);120 struct bio_slab *bslab;121 122 mutex_lock(&bio_slab_lock);123 bslab = xa_load(&bio_slabs, size);124 if (bslab)125 bslab->slab_ref++;126 else127 bslab = create_bio_slab(size);128 mutex_unlock(&bio_slab_lock);129 130 if (bslab)131 return bslab->slab;132 return NULL;133}134 135static void bio_put_slab(struct bio_set *bs)136{137 struct bio_slab *bslab = NULL;138 unsigned int slab_size = bs_bio_slab_size(bs);139 140 mutex_lock(&bio_slab_lock);141 142 bslab = xa_load(&bio_slabs, slab_size);143 if (WARN(!bslab, KERN_ERR "bio: unable to find slab!\n"))144 goto out;145 146 WARN_ON_ONCE(bslab->slab != bs->bio_slab);147 148 WARN_ON(!bslab->slab_ref);149 150 if (--bslab->slab_ref)151 goto out;152 153 xa_erase(&bio_slabs, slab_size);154 155 kmem_cache_destroy(bslab->slab);156 kfree(bslab);157 158out:159 mutex_unlock(&bio_slab_lock);160}161 162void bvec_free(mempool_t *pool, struct bio_vec *bv, unsigned short nr_vecs)163{164 BUG_ON(nr_vecs > BIO_MAX_VECS);165 166 if (nr_vecs == BIO_MAX_VECS)167 mempool_free(bv, pool);168 else if (nr_vecs > BIO_INLINE_VECS)169 kmem_cache_free(biovec_slab(nr_vecs)->slab, bv);170}171 172/*173 * Make the first allocation restricted and don't dump info on allocation174 * failures, since we'll fall back to the mempool in case of failure.175 */176static inline gfp_t bvec_alloc_gfp(gfp_t gfp)177{178 return (gfp & ~(__GFP_DIRECT_RECLAIM | __GFP_IO)) |179 __GFP_NOMEMALLOC | __GFP_NORETRY | __GFP_NOWARN;180}181 182struct bio_vec *bvec_alloc(mempool_t *pool, unsigned short *nr_vecs,183 gfp_t gfp_mask)184{185 struct biovec_slab *bvs = biovec_slab(*nr_vecs);186 187 if (WARN_ON_ONCE(!bvs))188 return NULL;189 190 /*191 * Upgrade the nr_vecs request to take full advantage of the allocation.192 * We also rely on this in the bvec_free path.193 */194 *nr_vecs = bvs->nr_vecs;195 196 /*197 * Try a slab allocation first for all smaller allocations. If that198 * fails and __GFP_DIRECT_RECLAIM is set retry with the mempool.199 * The mempool is sized to handle up to BIO_MAX_VECS entries.200 */201 if (*nr_vecs < BIO_MAX_VECS) {202 struct bio_vec *bvl;203 204 bvl = kmem_cache_alloc(bvs->slab, bvec_alloc_gfp(gfp_mask));205 if (likely(bvl) || !(gfp_mask & __GFP_DIRECT_RECLAIM))206 return bvl;207 *nr_vecs = BIO_MAX_VECS;208 }209 210 return mempool_alloc(pool, gfp_mask);211}212 213void bio_uninit(struct bio *bio)214{215#ifdef CONFIG_BLK_CGROUP216 if (bio->bi_blkg) {217 blkg_put(bio->bi_blkg);218 bio->bi_blkg = NULL;219 }220#endif221 if (bio_integrity(bio))222 bio_integrity_free(bio);223 224 bio_crypt_free_ctx(bio);225}226EXPORT_SYMBOL(bio_uninit);227 228static void bio_free(struct bio *bio)229{230 struct bio_set *bs = bio->bi_pool;231 void *p = bio;232 233 WARN_ON_ONCE(!bs);234 235 bio_uninit(bio);236 bvec_free(&bs->bvec_pool, bio->bi_io_vec, bio->bi_max_vecs);237 mempool_free(p - bs->front_pad, &bs->bio_pool);238}239 240/*241 * Users of this function have their own bio allocation. Subsequently,242 * they must remember to pair any call to bio_init() with bio_uninit()243 * when IO has completed, or when the bio is released.244 */245void bio_init(struct bio *bio, struct block_device *bdev, struct bio_vec *table,246 unsigned short max_vecs, blk_opf_t opf)247{248 bio->bi_next = NULL;249 bio->bi_bdev = bdev;250 bio->bi_opf = opf;251 bio->bi_flags = 0;252 bio->bi_ioprio = 0;253 bio->bi_write_hint = 0;254 bio->bi_status = 0;255 bio->bi_iter.bi_sector = 0;256 bio->bi_iter.bi_size = 0;257 bio->bi_iter.bi_idx = 0;258 bio->bi_iter.bi_bvec_done = 0;259 bio->bi_end_io = NULL;260 bio->bi_private = NULL;261#ifdef CONFIG_BLK_CGROUP262 bio->bi_blkg = NULL;263 bio->bi_issue.value = 0;264 if (bdev)265 bio_associate_blkg(bio);266#ifdef CONFIG_BLK_CGROUP_IOCOST267 bio->bi_iocost_cost = 0;268#endif269#endif270#ifdef CONFIG_BLK_INLINE_ENCRYPTION271 bio->bi_crypt_context = NULL;272#endif273#ifdef CONFIG_BLK_DEV_INTEGRITY274 bio->bi_integrity = NULL;275#endif276 bio->bi_vcnt = 0;277 278 atomic_set(&bio->__bi_remaining, 1);279 atomic_set(&bio->__bi_cnt, 1);280 bio->bi_cookie = BLK_QC_T_NONE;281 282 bio->bi_max_vecs = max_vecs;283 bio->bi_io_vec = table;284 bio->bi_pool = NULL;285}286EXPORT_SYMBOL(bio_init);287 288/**289 * bio_reset - reinitialize a bio290 * @bio: bio to reset291 * @bdev: block device to use the bio for292 * @opf: operation and flags for bio293 *294 * Description:295 * After calling bio_reset(), @bio will be in the same state as a freshly296 * allocated bio returned bio bio_alloc_bioset() - the only fields that are297 * preserved are the ones that are initialized by bio_alloc_bioset(). See298 * comment in struct bio.299 */300void bio_reset(struct bio *bio, struct block_device *bdev, blk_opf_t opf)301{302 bio_uninit(bio);303 memset(bio, 0, BIO_RESET_BYTES);304 atomic_set(&bio->__bi_remaining, 1);305 bio->bi_bdev = bdev;306 if (bio->bi_bdev)307 bio_associate_blkg(bio);308 bio->bi_opf = opf;309}310EXPORT_SYMBOL(bio_reset);311 312static struct bio *__bio_chain_endio(struct bio *bio)313{314 struct bio *parent = bio->bi_private;315 316 if (bio->bi_status && !parent->bi_status)317 parent->bi_status = bio->bi_status;318 bio_put(bio);319 return parent;320}321 322static void bio_chain_endio(struct bio *bio)323{324 bio_endio(__bio_chain_endio(bio));325}326 327/**328 * bio_chain - chain bio completions329 * @bio: the target bio330 * @parent: the parent bio of @bio331 *332 * The caller won't have a bi_end_io called when @bio completes - instead,333 * @parent's bi_end_io won't be called until both @parent and @bio have334 * completed; the chained bio will also be freed when it completes.335 *336 * The caller must not set bi_private or bi_end_io in @bio.337 */338void bio_chain(struct bio *bio, struct bio *parent)339{340 BUG_ON(bio->bi_private || bio->bi_end_io);341 342 bio->bi_private = parent;343 bio->bi_end_io = bio_chain_endio;344 bio_inc_remaining(parent);345}346EXPORT_SYMBOL(bio_chain);347 348/**349 * bio_chain_and_submit - submit a bio after chaining it to another one350 * @prev: bio to chain and submit351 * @new: bio to chain to352 *353 * If @prev is non-NULL, chain it to @new and submit it.354 *355 * Return: @new.356 */357struct bio *bio_chain_and_submit(struct bio *prev, struct bio *new)358{359 if (prev) {360 bio_chain(prev, new);361 submit_bio(prev);362 }363 return new;364}365 366struct bio *blk_next_bio(struct bio *bio, struct block_device *bdev,367 unsigned int nr_pages, blk_opf_t opf, gfp_t gfp)368{369 return bio_chain_and_submit(bio, bio_alloc(bdev, nr_pages, opf, gfp));370}371EXPORT_SYMBOL_GPL(blk_next_bio);372 373static void bio_alloc_rescue(struct work_struct *work)374{375 struct bio_set *bs = container_of(work, struct bio_set, rescue_work);376 struct bio *bio;377 378 while (1) {379 spin_lock(&bs->rescue_lock);380 bio = bio_list_pop(&bs->rescue_list);381 spin_unlock(&bs->rescue_lock);382 383 if (!bio)384 break;385 386 submit_bio_noacct(bio);387 }388}389 390static void punt_bios_to_rescuer(struct bio_set *bs)391{392 struct bio_list punt, nopunt;393 struct bio *bio;394 395 if (WARN_ON_ONCE(!bs->rescue_workqueue))396 return;397 /*398 * In order to guarantee forward progress we must punt only bios that399 * were allocated from this bio_set; otherwise, if there was a bio on400 * there for a stacking driver higher up in the stack, processing it401 * could require allocating bios from this bio_set, and doing that from402 * our own rescuer would be bad.403 *404 * Since bio lists are singly linked, pop them all instead of trying to405 * remove from the middle of the list:406 */407 408 bio_list_init(&punt);409 bio_list_init(&nopunt);410 411 while ((bio = bio_list_pop(¤t->bio_list[0])))412 bio_list_add(bio->bi_pool == bs ? &punt : &nopunt, bio);413 current->bio_list[0] = nopunt;414 415 bio_list_init(&nopunt);416 while ((bio = bio_list_pop(¤t->bio_list[1])))417 bio_list_add(bio->bi_pool == bs ? &punt : &nopunt, bio);418 current->bio_list[1] = nopunt;419 420 spin_lock(&bs->rescue_lock);421 bio_list_merge(&bs->rescue_list, &punt);422 spin_unlock(&bs->rescue_lock);423 424 queue_work(bs->rescue_workqueue, &bs->rescue_work);425}426 427static void bio_alloc_irq_cache_splice(struct bio_alloc_cache *cache)428{429 unsigned long flags;430 431 /* cache->free_list must be empty */432 if (WARN_ON_ONCE(cache->free_list))433 return;434 435 local_irq_save(flags);436 cache->free_list = cache->free_list_irq;437 cache->free_list_irq = NULL;438 cache->nr += cache->nr_irq;439 cache->nr_irq = 0;440 local_irq_restore(flags);441}442 443static struct bio *bio_alloc_percpu_cache(struct block_device *bdev,444 unsigned short nr_vecs, blk_opf_t opf, gfp_t gfp,445 struct bio_set *bs)446{447 struct bio_alloc_cache *cache;448 struct bio *bio;449 450 cache = per_cpu_ptr(bs->cache, get_cpu());451 if (!cache->free_list) {452 if (READ_ONCE(cache->nr_irq) >= ALLOC_CACHE_THRESHOLD)453 bio_alloc_irq_cache_splice(cache);454 if (!cache->free_list) {455 put_cpu();456 return NULL;457 }458 }459 bio = cache->free_list;460 cache->free_list = bio->bi_next;461 cache->nr--;462 put_cpu();463 464 bio_init(bio, bdev, nr_vecs ? bio->bi_inline_vecs : NULL, nr_vecs, opf);465 bio->bi_pool = bs;466 return bio;467}468 469/**470 * bio_alloc_bioset - allocate a bio for I/O471 * @bdev: block device to allocate the bio for (can be %NULL)472 * @nr_vecs: number of bvecs to pre-allocate473 * @opf: operation and flags for bio474 * @gfp_mask: the GFP_* mask given to the slab allocator475 * @bs: the bio_set to allocate from.476 *477 * Allocate a bio from the mempools in @bs.478 *479 * If %__GFP_DIRECT_RECLAIM is set then bio_alloc will always be able to480 * allocate a bio. This is due to the mempool guarantees. To make this work,481 * callers must never allocate more than 1 bio at a time from the general pool.482 * Callers that need to allocate more than 1 bio must always submit the483 * previously allocated bio for IO before attempting to allocate a new one.484 * Failure to do so can cause deadlocks under memory pressure.485 *486 * Note that when running under submit_bio_noacct() (i.e. any block driver),487 * bios are not submitted until after you return - see the code in488 * submit_bio_noacct() that converts recursion into iteration, to prevent489 * stack overflows.490 *491 * This would normally mean allocating multiple bios under submit_bio_noacct()492 * would be susceptible to deadlocks, but we have493 * deadlock avoidance code that resubmits any blocked bios from a rescuer494 * thread.495 *496 * However, we do not guarantee forward progress for allocations from other497 * mempools. Doing multiple allocations from the same mempool under498 * submit_bio_noacct() should be avoided - instead, use bio_set's front_pad499 * for per bio allocations.500 *501 * Returns: Pointer to new bio on success, NULL on failure.502 */503struct bio *bio_alloc_bioset(struct block_device *bdev, unsigned short nr_vecs,504 blk_opf_t opf, gfp_t gfp_mask,505 struct bio_set *bs)506{507 gfp_t saved_gfp = gfp_mask;508 struct bio *bio;509 void *p;510 511 /* should not use nobvec bioset for nr_vecs > 0 */512 if (WARN_ON_ONCE(!mempool_initialized(&bs->bvec_pool) && nr_vecs > 0))513 return NULL;514 515 if (opf & REQ_ALLOC_CACHE) {516 if (bs->cache && nr_vecs <= BIO_INLINE_VECS) {517 bio = bio_alloc_percpu_cache(bdev, nr_vecs, opf,518 gfp_mask, bs);519 if (bio)520 return bio;521 /*522 * No cached bio available, bio returned below marked with523 * REQ_ALLOC_CACHE to particpate in per-cpu alloc cache.524 */525 } else {526 opf &= ~REQ_ALLOC_CACHE;527 }528 }529 530 /*531 * submit_bio_noacct() converts recursion to iteration; this means if532 * we're running beneath it, any bios we allocate and submit will not be533 * submitted (and thus freed) until after we return.534 *535 * This exposes us to a potential deadlock if we allocate multiple bios536 * from the same bio_set() while running underneath submit_bio_noacct().537 * If we were to allocate multiple bios (say a stacking block driver538 * that was splitting bios), we would deadlock if we exhausted the539 * mempool's reserve.540 *541 * We solve this, and guarantee forward progress, with a rescuer542 * workqueue per bio_set. If we go to allocate and there are bios on543 * current->bio_list, we first try the allocation without544 * __GFP_DIRECT_RECLAIM; if that fails, we punt those bios we would be545 * blocking to the rescuer workqueue before we retry with the original546 * gfp_flags.547 */548 if (current->bio_list &&549 (!bio_list_empty(¤t->bio_list[0]) ||550 !bio_list_empty(¤t->bio_list[1])) &&551 bs->rescue_workqueue)552 gfp_mask &= ~__GFP_DIRECT_RECLAIM;553 554 p = mempool_alloc(&bs->bio_pool, gfp_mask);555 if (!p && gfp_mask != saved_gfp) {556 punt_bios_to_rescuer(bs);557 gfp_mask = saved_gfp;558 p = mempool_alloc(&bs->bio_pool, gfp_mask);559 }560 if (unlikely(!p))561 return NULL;562 if (!mempool_is_saturated(&bs->bio_pool))563 opf &= ~REQ_ALLOC_CACHE;564 565 bio = p + bs->front_pad;566 if (nr_vecs > BIO_INLINE_VECS) {567 struct bio_vec *bvl = NULL;568 569 bvl = bvec_alloc(&bs->bvec_pool, &nr_vecs, gfp_mask);570 if (!bvl && gfp_mask != saved_gfp) {571 punt_bios_to_rescuer(bs);572 gfp_mask = saved_gfp;573 bvl = bvec_alloc(&bs->bvec_pool, &nr_vecs, gfp_mask);574 }575 if (unlikely(!bvl))576 goto err_free;577 578 bio_init(bio, bdev, bvl, nr_vecs, opf);579 } else if (nr_vecs) {580 bio_init(bio, bdev, bio->bi_inline_vecs, BIO_INLINE_VECS, opf);581 } else {582 bio_init(bio, bdev, NULL, 0, opf);583 }584 585 bio->bi_pool = bs;586 return bio;587 588err_free:589 mempool_free(p, &bs->bio_pool);590 return NULL;591}592EXPORT_SYMBOL(bio_alloc_bioset);593 594/**595 * bio_kmalloc - kmalloc a bio596 * @nr_vecs: number of bio_vecs to allocate597 * @gfp_mask: the GFP_* mask given to the slab allocator598 *599 * Use kmalloc to allocate a bio (including bvecs). The bio must be initialized600 * using bio_init() before use. To free a bio returned from this function use601 * kfree() after calling bio_uninit(). A bio returned from this function can602 * be reused by calling bio_uninit() before calling bio_init() again.603 *604 * Note that unlike bio_alloc() or bio_alloc_bioset() allocations from this605 * function are not backed by a mempool can fail. Do not use this function606 * for allocations in the file system I/O path.607 *608 * Returns: Pointer to new bio on success, NULL on failure.609 */610struct bio *bio_kmalloc(unsigned short nr_vecs, gfp_t gfp_mask)611{612 struct bio *bio;613 614 if (nr_vecs > UIO_MAXIOV)615 return NULL;616 return kmalloc(struct_size(bio, bi_inline_vecs, nr_vecs), gfp_mask);617}618EXPORT_SYMBOL(bio_kmalloc);619 620void zero_fill_bio_iter(struct bio *bio, struct bvec_iter start)621{622 struct bio_vec bv;623 struct bvec_iter iter;624 625 __bio_for_each_segment(bv, bio, iter, start)626 memzero_bvec(&bv);627}628EXPORT_SYMBOL(zero_fill_bio_iter);629 630/**631 * bio_truncate - truncate the bio to small size of @new_size632 * @bio: the bio to be truncated633 * @new_size: new size for truncating the bio634 *635 * Description:636 * Truncate the bio to new size of @new_size. If bio_op(bio) is637 * REQ_OP_READ, zero the truncated part. This function should only638 * be used for handling corner cases, such as bio eod.639 */640static void bio_truncate(struct bio *bio, unsigned new_size)641{642 struct bio_vec bv;643 struct bvec_iter iter;644 unsigned int done = 0;645 bool truncated = false;646 647 if (new_size >= bio->bi_iter.bi_size)648 return;649 650 if (bio_op(bio) != REQ_OP_READ)651 goto exit;652 653 bio_for_each_segment(bv, bio, iter) {654 if (done + bv.bv_len > new_size) {655 unsigned offset;656 657 if (!truncated)658 offset = new_size - done;659 else660 offset = 0;661 zero_user(bv.bv_page, bv.bv_offset + offset,662 bv.bv_len - offset);663 truncated = true;664 }665 done += bv.bv_len;666 }667 668 exit:669 /*670 * Don't touch bvec table here and make it really immutable, since671 * fs bio user has to retrieve all pages via bio_for_each_segment_all672 * in its .end_bio() callback.673 *674 * It is enough to truncate bio by updating .bi_size since we can make675 * correct bvec with the updated .bi_size for drivers.676 */677 bio->bi_iter.bi_size = new_size;678}679 680/**681 * guard_bio_eod - truncate a BIO to fit the block device682 * @bio: bio to truncate683 *684 * This allows us to do IO even on the odd last sectors of a device, even if the685 * block size is some multiple of the physical sector size.686 *687 * We'll just truncate the bio to the size of the device, and clear the end of688 * the buffer head manually. Truly out-of-range accesses will turn into actual689 * I/O errors, this only handles the "we need to be able to do I/O at the final690 * sector" case.691 */692void guard_bio_eod(struct bio *bio)693{694 sector_t maxsector = bdev_nr_sectors(bio->bi_bdev);695 696 if (!maxsector)697 return;698 699 /*700 * If the *whole* IO is past the end of the device,701 * let it through, and the IO layer will turn it into702 * an EIO.703 */704 if (unlikely(bio->bi_iter.bi_sector >= maxsector))705 return;706 707 maxsector -= bio->bi_iter.bi_sector;708 if (likely((bio->bi_iter.bi_size >> 9) <= maxsector))709 return;710 711 bio_truncate(bio, maxsector << 9);712}713 714static int __bio_alloc_cache_prune(struct bio_alloc_cache *cache,715 unsigned int nr)716{717 unsigned int i = 0;718 struct bio *bio;719 720 while ((bio = cache->free_list) != NULL) {721 cache->free_list = bio->bi_next;722 cache->nr--;723 bio_free(bio);724 if (++i == nr)725 break;726 }727 return i;728}729 730static void bio_alloc_cache_prune(struct bio_alloc_cache *cache,731 unsigned int nr)732{733 nr -= __bio_alloc_cache_prune(cache, nr);734 if (!READ_ONCE(cache->free_list)) {735 bio_alloc_irq_cache_splice(cache);736 __bio_alloc_cache_prune(cache, nr);737 }738}739 740static int bio_cpu_dead(unsigned int cpu, struct hlist_node *node)741{742 struct bio_set *bs;743 744 bs = hlist_entry_safe(node, struct bio_set, cpuhp_dead);745 if (bs->cache) {746 struct bio_alloc_cache *cache = per_cpu_ptr(bs->cache, cpu);747 748 bio_alloc_cache_prune(cache, -1U);749 }750 return 0;751}752 753static void bio_alloc_cache_destroy(struct bio_set *bs)754{755 int cpu;756 757 if (!bs->cache)758 return;759 760 cpuhp_state_remove_instance_nocalls(CPUHP_BIO_DEAD, &bs->cpuhp_dead);761 for_each_possible_cpu(cpu) {762 struct bio_alloc_cache *cache;763 764 cache = per_cpu_ptr(bs->cache, cpu);765 bio_alloc_cache_prune(cache, -1U);766 }767 free_percpu(bs->cache);768 bs->cache = NULL;769}770 771static inline void bio_put_percpu_cache(struct bio *bio)772{773 struct bio_alloc_cache *cache;774 775 cache = per_cpu_ptr(bio->bi_pool->cache, get_cpu());776 if (READ_ONCE(cache->nr_irq) + cache->nr > ALLOC_CACHE_MAX)777 goto out_free;778 779 if (in_task()) {780 bio_uninit(bio);781 bio->bi_next = cache->free_list;782 /* Not necessary but helps not to iopoll already freed bios */783 bio->bi_bdev = NULL;784 cache->free_list = bio;785 cache->nr++;786 } else if (in_hardirq()) {787 lockdep_assert_irqs_disabled();788 789 bio_uninit(bio);790 bio->bi_next = cache->free_list_irq;791 cache->free_list_irq = bio;792 cache->nr_irq++;793 } else {794 goto out_free;795 }796 put_cpu();797 return;798out_free:799 put_cpu();800 bio_free(bio);801}802 803/**804 * bio_put - release a reference to a bio805 * @bio: bio to release reference to806 *807 * Description:808 * Put a reference to a &struct bio, either one you have gotten with809 * bio_alloc, bio_get or bio_clone_*. The last put of a bio will free it.810 **/811void bio_put(struct bio *bio)812{813 if (unlikely(bio_flagged(bio, BIO_REFFED))) {814 BUG_ON(!atomic_read(&bio->__bi_cnt));815 if (!atomic_dec_and_test(&bio->__bi_cnt))816 return;817 }818 if (bio->bi_opf & REQ_ALLOC_CACHE)819 bio_put_percpu_cache(bio);820 else821 bio_free(bio);822}823EXPORT_SYMBOL(bio_put);824 825static int __bio_clone(struct bio *bio, struct bio *bio_src, gfp_t gfp)826{827 bio_set_flag(bio, BIO_CLONED);828 bio->bi_ioprio = bio_src->bi_ioprio;829 bio->bi_write_hint = bio_src->bi_write_hint;830 bio->bi_iter = bio_src->bi_iter;831 832 if (bio->bi_bdev) {833 if (bio->bi_bdev == bio_src->bi_bdev &&834 bio_flagged(bio_src, BIO_REMAPPED))835 bio_set_flag(bio, BIO_REMAPPED);836 bio_clone_blkg_association(bio, bio_src);837 }838 839 if (bio_crypt_clone(bio, bio_src, gfp) < 0)840 return -ENOMEM;841 if (bio_integrity(bio_src) &&842 bio_integrity_clone(bio, bio_src, gfp) < 0)843 return -ENOMEM;844 return 0;845}846 847/**848 * bio_alloc_clone - clone a bio that shares the original bio's biovec849 * @bdev: block_device to clone onto850 * @bio_src: bio to clone from851 * @gfp: allocation priority852 * @bs: bio_set to allocate from853 *854 * Allocate a new bio that is a clone of @bio_src. The caller owns the returned855 * bio, but not the actual data it points to.856 *857 * The caller must ensure that the return bio is not freed before @bio_src.858 */859struct bio *bio_alloc_clone(struct block_device *bdev, struct bio *bio_src,860 gfp_t gfp, struct bio_set *bs)861{862 struct bio *bio;863 864 bio = bio_alloc_bioset(bdev, 0, bio_src->bi_opf, gfp, bs);865 if (!bio)866 return NULL;867 868 if (__bio_clone(bio, bio_src, gfp) < 0) {869 bio_put(bio);870 return NULL;871 }872 bio->bi_io_vec = bio_src->bi_io_vec;873 874 return bio;875}876EXPORT_SYMBOL(bio_alloc_clone);877 878/**879 * bio_init_clone - clone a bio that shares the original bio's biovec880 * @bdev: block_device to clone onto881 * @bio: bio to clone into882 * @bio_src: bio to clone from883 * @gfp: allocation priority884 *885 * Initialize a new bio in caller provided memory that is a clone of @bio_src.886 * The caller owns the returned bio, but not the actual data it points to.887 *888 * The caller must ensure that @bio_src is not freed before @bio.889 */890int bio_init_clone(struct block_device *bdev, struct bio *bio,891 struct bio *bio_src, gfp_t gfp)892{893 int ret;894 895 bio_init(bio, bdev, bio_src->bi_io_vec, 0, bio_src->bi_opf);896 ret = __bio_clone(bio, bio_src, gfp);897 if (ret)898 bio_uninit(bio);899 return ret;900}901EXPORT_SYMBOL(bio_init_clone);902 903/**904 * bio_full - check if the bio is full905 * @bio: bio to check906 * @len: length of one segment to be added907 *908 * Return true if @bio is full and one segment with @len bytes can't be909 * added to the bio, otherwise return false910 */911static inline bool bio_full(struct bio *bio, unsigned len)912{913 if (bio->bi_vcnt >= bio->bi_max_vecs)914 return true;915 if (bio->bi_iter.bi_size > UINT_MAX - len)916 return true;917 return false;918}919 920static bool bvec_try_merge_page(struct bio_vec *bv, struct page *page,921 unsigned int len, unsigned int off, bool *same_page)922{923 size_t bv_end = bv->bv_offset + bv->bv_len;924 phys_addr_t vec_end_addr = page_to_phys(bv->bv_page) + bv_end - 1;925 phys_addr_t page_addr = page_to_phys(page);926 927 if (vec_end_addr + 1 != page_addr + off)928 return false;929 if (xen_domain() && !xen_biovec_phys_mergeable(bv, page))930 return false;931 if (!zone_device_pages_have_same_pgmap(bv->bv_page, page))932 return false;933 934 *same_page = ((vec_end_addr & PAGE_MASK) == ((page_addr + off) &935 PAGE_MASK));936 if (!*same_page) {937 if (IS_ENABLED(CONFIG_KMSAN))938 return false;939 if (bv->bv_page + bv_end / PAGE_SIZE != page + off / PAGE_SIZE)940 return false;941 }942 943 bv->bv_len += len;944 return true;945}946 947/*948 * Try to merge a page into a segment, while obeying the hardware segment949 * size limit. This is not for normal read/write bios, but for passthrough950 * or Zone Append operations that we can't split.951 */952bool bvec_try_merge_hw_page(struct request_queue *q, struct bio_vec *bv,953 struct page *page, unsigned len, unsigned offset,954 bool *same_page)955{956 unsigned long mask = queue_segment_boundary(q);957 phys_addr_t addr1 = bvec_phys(bv);958 phys_addr_t addr2 = page_to_phys(page) + offset + len - 1;959 960 if ((addr1 | mask) != (addr2 | mask))961 return false;962 if (len > queue_max_segment_size(q) - bv->bv_len)963 return false;964 return bvec_try_merge_page(bv, page, len, offset, same_page);965}966 967/**968 * bio_add_hw_page - attempt to add a page to a bio with hw constraints969 * @q: the target queue970 * @bio: destination bio971 * @page: page to add972 * @len: vec entry length973 * @offset: vec entry offset974 * @max_sectors: maximum number of sectors that can be added975 * @same_page: return if the segment has been merged inside the same page976 *977 * Add a page to a bio while respecting the hardware max_sectors, max_segment978 * and gap limitations.979 */980int bio_add_hw_page(struct request_queue *q, struct bio *bio,981 struct page *page, unsigned int len, unsigned int offset,982 unsigned int max_sectors, bool *same_page)983{984 unsigned int max_size = max_sectors << SECTOR_SHIFT;985 986 if (WARN_ON_ONCE(bio_flagged(bio, BIO_CLONED)))987 return 0;988 989 len = min3(len, max_size, queue_max_segment_size(q));990 if (len > max_size - bio->bi_iter.bi_size)991 return 0;992 993 if (bio->bi_vcnt > 0) {994 struct bio_vec *bv = &bio->bi_io_vec[bio->bi_vcnt - 1];995 996 if (bvec_try_merge_hw_page(q, bv, page, len, offset,997 same_page)) {998 bio->bi_iter.bi_size += len;999 return len;1000 }1001 1002 if (bio->bi_vcnt >=1003 min(bio->bi_max_vecs, queue_max_segments(q)))1004 return 0;1005 1006 /*1007 * If the queue doesn't support SG gaps and adding this segment1008 * would create a gap, disallow it.1009 */1010 if (bvec_gap_to_prev(&q->limits, bv, offset))1011 return 0;1012 }1013 1014 bvec_set_page(&bio->bi_io_vec[bio->bi_vcnt], page, len, offset);1015 bio->bi_vcnt++;1016 bio->bi_iter.bi_size += len;1017 return len;1018}1019 1020/**1021 * bio_add_hw_folio - attempt to add a folio to a bio with hw constraints1022 * @q: the target queue1023 * @bio: destination bio1024 * @folio: folio to add1025 * @len: vec entry length1026 * @offset: vec entry offset in the folio1027 * @max_sectors: maximum number of sectors that can be added1028 * @same_page: return if the segment has been merged inside the same folio1029 *1030 * Add a folio to a bio while respecting the hardware max_sectors, max_segment1031 * and gap limitations.1032 */1033int bio_add_hw_folio(struct request_queue *q, struct bio *bio,1034 struct folio *folio, size_t len, size_t offset,1035 unsigned int max_sectors, bool *same_page)1036{1037 if (len > UINT_MAX || offset > UINT_MAX)1038 return 0;1039 return bio_add_hw_page(q, bio, folio_page(folio, 0), len, offset,1040 max_sectors, same_page);1041}1042 1043/**1044 * bio_add_pc_page - attempt to add page to passthrough bio1045 * @q: the target queue1046 * @bio: destination bio1047 * @page: page to add1048 * @len: vec entry length1049 * @offset: vec entry offset1050 *1051 * Attempt to add a page to the bio_vec maplist. This can fail for a1052 * number of reasons, such as the bio being full or target block device1053 * limitations. The target block device must allow bio's up to PAGE_SIZE,1054 * so it is always possible to add a single page to an empty bio.1055 *1056 * This should only be used by passthrough bios.1057 */1058int bio_add_pc_page(struct request_queue *q, struct bio *bio,1059 struct page *page, unsigned int len, unsigned int offset)1060{1061 bool same_page = false;1062 return bio_add_hw_page(q, bio, page, len, offset,1063 queue_max_hw_sectors(q), &same_page);1064}1065EXPORT_SYMBOL(bio_add_pc_page);1066 1067/**1068 * bio_add_zone_append_page - attempt to add page to zone-append bio1069 * @bio: destination bio1070 * @page: page to add1071 * @len: vec entry length1072 * @offset: vec entry offset1073 *1074 * Attempt to add a page to the bio_vec maplist of a bio that will be submitted1075 * for a zone-append request. This can fail for a number of reasons, such as the1076 * bio being full or the target block device is not a zoned block device or1077 * other limitations of the target block device. The target block device must1078 * allow bio's up to PAGE_SIZE, so it is always possible to add a single page1079 * to an empty bio.1080 *1081 * Returns: number of bytes added to the bio, or 0 in case of a failure.1082 */1083int bio_add_zone_append_page(struct bio *bio, struct page *page,1084 unsigned int len, unsigned int offset)1085{1086 struct request_queue *q = bdev_get_queue(bio->bi_bdev);1087 bool same_page = false;1088 1089 if (WARN_ON_ONCE(bio_op(bio) != REQ_OP_ZONE_APPEND))1090 return 0;1091 1092 if (WARN_ON_ONCE(!bdev_is_zoned(bio->bi_bdev)))1093 return 0;1094 1095 return bio_add_hw_page(q, bio, page, len, offset,1096 queue_max_zone_append_sectors(q), &same_page);1097}1098EXPORT_SYMBOL_GPL(bio_add_zone_append_page);1099 1100/**1101 * __bio_add_page - add page(s) to a bio in a new segment1102 * @bio: destination bio1103 * @page: start page to add1104 * @len: length of the data to add, may cross pages1105 * @off: offset of the data relative to @page, may cross pages1106 *1107 * Add the data at @page + @off to @bio as a new bvec. The caller must ensure1108 * that @bio has space for another bvec.1109 */1110void __bio_add_page(struct bio *bio, struct page *page,1111 unsigned int len, unsigned int off)1112{1113 WARN_ON_ONCE(bio_flagged(bio, BIO_CLONED));1114 WARN_ON_ONCE(bio_full(bio, len));1115 1116 bvec_set_page(&bio->bi_io_vec[bio->bi_vcnt], page, len, off);1117 bio->bi_iter.bi_size += len;1118 bio->bi_vcnt++;1119}1120EXPORT_SYMBOL_GPL(__bio_add_page);1121 1122/**1123 * bio_add_page - attempt to add page(s) to bio1124 * @bio: destination bio1125 * @page: start page to add1126 * @len: vec entry length, may cross pages1127 * @offset: vec entry offset relative to @page, may cross pages1128 *1129 * Attempt to add page(s) to the bio_vec maplist. This will only fail1130 * if either bio->bi_vcnt == bio->bi_max_vecs or it's a cloned bio.1131 */1132int bio_add_page(struct bio *bio, struct page *page,1133 unsigned int len, unsigned int offset)1134{1135 bool same_page = false;1136 1137 if (WARN_ON_ONCE(bio_flagged(bio, BIO_CLONED)))1138 return 0;1139 if (bio->bi_iter.bi_size > UINT_MAX - len)1140 return 0;1141 1142 if (bio->bi_vcnt > 0 &&1143 bvec_try_merge_page(&bio->bi_io_vec[bio->bi_vcnt - 1],1144 page, len, offset, &same_page)) {1145 bio->bi_iter.bi_size += len;1146 return len;1147 }1148 1149 if (bio->bi_vcnt >= bio->bi_max_vecs)1150 return 0;1151 __bio_add_page(bio, page, len, offset);1152 return len;1153}1154EXPORT_SYMBOL(bio_add_page);1155 1156void bio_add_folio_nofail(struct bio *bio, struct folio *folio, size_t len,1157 size_t off)1158{1159 WARN_ON_ONCE(len > UINT_MAX);1160 WARN_ON_ONCE(off > UINT_MAX);1161 __bio_add_page(bio, &folio->page, len, off);1162}1163EXPORT_SYMBOL_GPL(bio_add_folio_nofail);1164 1165/**1166 * bio_add_folio - Attempt to add part of a folio to a bio.1167 * @bio: BIO to add to.1168 * @folio: Folio to add.1169 * @len: How many bytes from the folio to add.1170 * @off: First byte in this folio to add.1171 *1172 * Filesystems that use folios can call this function instead of calling1173 * bio_add_page() for each page in the folio. If @off is bigger than1174 * PAGE_SIZE, this function can create a bio_vec that starts in a page1175 * after the bv_page. BIOs do not support folios that are 4GiB or larger.1176 *1177 * Return: Whether the addition was successful.1178 */1179bool bio_add_folio(struct bio *bio, struct folio *folio, size_t len,1180 size_t off)1181{1182 if (len > UINT_MAX || off > UINT_MAX)1183 return false;1184 return bio_add_page(bio, &folio->page, len, off) > 0;1185}1186EXPORT_SYMBOL(bio_add_folio);1187 1188void __bio_release_pages(struct bio *bio, bool mark_dirty)1189{1190 struct folio_iter fi;1191 1192 bio_for_each_folio_all(fi, bio) {1193 size_t nr_pages;1194 1195 if (mark_dirty) {1196 folio_lock(fi.folio);1197 folio_mark_dirty(fi.folio);1198 folio_unlock(fi.folio);1199 }1200 nr_pages = (fi.offset + fi.length - 1) / PAGE_SIZE -1201 fi.offset / PAGE_SIZE + 1;1202 unpin_user_folio(fi.folio, nr_pages);1203 }1204}1205EXPORT_SYMBOL_GPL(__bio_release_pages);1206 1207void bio_iov_bvec_set(struct bio *bio, struct iov_iter *iter)1208{1209 size_t size = iov_iter_count(iter);1210 1211 WARN_ON_ONCE(bio->bi_max_vecs);1212 1213 if (bio_op(bio) == REQ_OP_ZONE_APPEND) {1214 struct request_queue *q = bdev_get_queue(bio->bi_bdev);1215 size_t max_sectors = queue_max_zone_append_sectors(q);1216 1217 size = min(size, max_sectors << SECTOR_SHIFT);1218 }1219 1220 bio->bi_vcnt = iter->nr_segs;1221 bio->bi_io_vec = (struct bio_vec *)iter->bvec;1222 bio->bi_iter.bi_bvec_done = iter->iov_offset;1223 bio->bi_iter.bi_size = size;1224 bio_set_flag(bio, BIO_CLONED);1225}1226 1227static int bio_iov_add_folio(struct bio *bio, struct folio *folio, size_t len,1228 size_t offset)1229{1230 bool same_page = false;1231 1232 if (WARN_ON_ONCE(bio->bi_iter.bi_size > UINT_MAX - len))1233 return -EIO;1234 1235 if (bio->bi_vcnt > 0 &&1236 bvec_try_merge_page(&bio->bi_io_vec[bio->bi_vcnt - 1],1237 folio_page(folio, 0), len, offset,1238 &same_page)) {1239 bio->bi_iter.bi_size += len;1240 if (same_page && bio_flagged(bio, BIO_PAGE_PINNED))1241 unpin_user_folio(folio, 1);1242 return 0;1243 }1244 bio_add_folio_nofail(bio, folio, len, offset);1245 return 0;1246}1247 1248static int bio_iov_add_zone_append_folio(struct bio *bio, struct folio *folio,1249 size_t len, size_t offset)1250{1251 struct request_queue *q = bdev_get_queue(bio->bi_bdev);1252 bool same_page = false;1253 1254 if (bio_add_hw_folio(q, bio, folio, len, offset,1255 queue_max_zone_append_sectors(q), &same_page) != len)1256 return -EINVAL;1257 if (same_page && bio_flagged(bio, BIO_PAGE_PINNED))1258 unpin_user_folio(folio, 1);1259 return 0;1260}1261 1262static unsigned int get_contig_folio_len(unsigned int *num_pages,1263 struct page **pages, unsigned int i,1264 struct folio *folio, size_t left,1265 size_t offset)1266{1267 size_t bytes = left;1268 size_t contig_sz = min_t(size_t, PAGE_SIZE - offset, bytes);1269 unsigned int j;1270 1271 /*1272 * We might COW a single page in the middle of1273 * a large folio, so we have to check that all1274 * pages belong to the same folio.1275 */1276 bytes -= contig_sz;1277 for (j = i + 1; j < i + *num_pages; j++) {1278 size_t next = min_t(size_t, PAGE_SIZE, bytes);1279 1280 if (page_folio(pages[j]) != folio ||1281 pages[j] != pages[j - 1] + 1) {1282 break;1283 }1284 contig_sz += next;1285 bytes -= next;1286 }1287 *num_pages = j - i;1288 1289 return contig_sz;1290}1291 1292#define PAGE_PTRS_PER_BVEC (sizeof(struct bio_vec) / sizeof(struct page *))1293 1294/**1295 * __bio_iov_iter_get_pages - pin user or kernel pages and add them to a bio1296 * @bio: bio to add pages to1297 * @iter: iov iterator describing the region to be mapped1298 *1299 * Extracts pages from *iter and appends them to @bio's bvec array. The pages1300 * will have to be cleaned up in the way indicated by the BIO_PAGE_PINNED flag.1301 * For a multi-segment *iter, this function only adds pages from the next1302 * non-empty segment of the iov iterator.1303 */1304static int __bio_iov_iter_get_pages(struct bio *bio, struct iov_iter *iter)1305{1306 iov_iter_extraction_t extraction_flags = 0;1307 unsigned short nr_pages = bio->bi_max_vecs - bio->bi_vcnt;1308 unsigned short entries_left = bio->bi_max_vecs - bio->bi_vcnt;1309 struct bio_vec *bv = bio->bi_io_vec + bio->bi_vcnt;1310 struct page **pages = (struct page **)bv;1311 ssize_t size;1312 unsigned int num_pages, i = 0;1313 size_t offset, folio_offset, left, len;1314 int ret = 0;1315 1316 /*1317 * Move page array up in the allocated memory for the bio vecs as far as1318 * possible so that we can start filling biovecs from the beginning1319 * without overwriting the temporary page array.1320 */1321 BUILD_BUG_ON(PAGE_PTRS_PER_BVEC < 2);1322 pages += entries_left * (PAGE_PTRS_PER_BVEC - 1);1323 1324 if (bio->bi_bdev && blk_queue_pci_p2pdma(bio->bi_bdev->bd_disk->queue))1325 extraction_flags |= ITER_ALLOW_P2PDMA;1326 1327 /*1328 * Each segment in the iov is required to be a block size multiple.1329 * However, we may not be able to get the entire segment if it spans1330 * more pages than bi_max_vecs allows, so we have to ALIGN_DOWN the1331 * result to ensure the bio's total size is correct. The remainder of1332 * the iov data will be picked up in the next bio iteration.1333 */1334 size = iov_iter_extract_pages(iter, &pages,1335 UINT_MAX - bio->bi_iter.bi_size,1336 nr_pages, extraction_flags, &offset);1337 if (unlikely(size <= 0))1338 return size ? size : -EFAULT;1339 1340 nr_pages = DIV_ROUND_UP(offset + size, PAGE_SIZE);1341 1342 if (bio->bi_bdev) {1343 size_t trim = size & (bdev_logical_block_size(bio->bi_bdev) - 1);1344 iov_iter_revert(iter, trim);1345 size -= trim;1346 }1347 1348 if (unlikely(!size)) {1349 ret = -EFAULT;1350 goto out;1351 }1352 1353 for (left = size, i = 0; left > 0; left -= len, i += num_pages) {1354 struct page *page = pages[i];1355 struct folio *folio = page_folio(page);1356 1357 folio_offset = ((size_t)folio_page_idx(folio, page) <<1358 PAGE_SHIFT) + offset;1359 1360 len = min(folio_size(folio) - folio_offset, left);1361 1362 num_pages = DIV_ROUND_UP(offset + len, PAGE_SIZE);1363 1364 if (num_pages > 1)1365 len = get_contig_folio_len(&num_pages, pages, i,1366 folio, left, offset);1367 1368 if (bio_op(bio) == REQ_OP_ZONE_APPEND) {1369 ret = bio_iov_add_zone_append_folio(bio, folio, len,1370 folio_offset);1371 if (ret)1372 break;1373 } else1374 bio_iov_add_folio(bio, folio, len, folio_offset);1375 1376 offset = 0;1377 }1378 1379 iov_iter_revert(iter, left);1380out:1381 while (i < nr_pages)1382 bio_release_page(bio, pages[i++]);1383 1384 return ret;1385}1386 1387/**1388 * bio_iov_iter_get_pages - add user or kernel pages to a bio1389 * @bio: bio to add pages to1390 * @iter: iov iterator describing the region to be added1391 *1392 * This takes either an iterator pointing to user memory, or one pointing to1393 * kernel pages (BVEC iterator). If we're adding user pages, we pin them and1394 * map them into the kernel. On IO completion, the caller should put those1395 * pages. For bvec based iterators bio_iov_iter_get_pages() uses the provided1396 * bvecs rather than copying them. Hence anyone issuing kiocb based IO needs1397 * to ensure the bvecs and pages stay referenced until the submitted I/O is1398 * completed by a call to ->ki_complete() or returns with an error other than1399 * -EIOCBQUEUED. The caller needs to check if the bio is flagged BIO_NO_PAGE_REF1400 * on IO completion. If it isn't, then pages should be released.1401 *1402 * The function tries, but does not guarantee, to pin as many pages as1403 * fit into the bio, or are requested in @iter, whatever is smaller. If1404 * MM encounters an error pinning the requested pages, it stops. Error1405 * is returned only if 0 pages could be pinned.1406 */1407int bio_iov_iter_get_pages(struct bio *bio, struct iov_iter *iter)1408{1409 int ret = 0;1410 1411 if (WARN_ON_ONCE(bio_flagged(bio, BIO_CLONED)))1412 return -EIO;1413 1414 if (iov_iter_is_bvec(iter)) {1415 bio_iov_bvec_set(bio, iter);1416 iov_iter_advance(iter, bio->bi_iter.bi_size);1417 return 0;1418 }1419 1420 if (iov_iter_extract_will_pin(iter))1421 bio_set_flag(bio, BIO_PAGE_PINNED);1422 do {1423 ret = __bio_iov_iter_get_pages(bio, iter);1424 } while (!ret && iov_iter_count(iter) && !bio_full(bio, 0));1425 1426 return bio->bi_vcnt ? 0 : ret;1427}1428EXPORT_SYMBOL_GPL(bio_iov_iter_get_pages);1429 1430static void submit_bio_wait_endio(struct bio *bio)1431{1432 complete(bio->bi_private);1433}1434 1435/**1436 * submit_bio_wait - submit a bio, and wait until it completes1437 * @bio: The &struct bio which describes the I/O1438 *1439 * Simple wrapper around submit_bio(). Returns 0 on success, or the error from1440 * bio_endio() on failure.1441 *1442 * WARNING: Unlike to how submit_bio() is usually used, this function does not1443 * result in bio reference to be consumed. The caller must drop the reference1444 * on his own.1445 */1446int submit_bio_wait(struct bio *bio)1447{1448 DECLARE_COMPLETION_ONSTACK_MAP(done,1449 bio->bi_bdev->bd_disk->lockdep_map);1450 1451 bio->bi_private = &done;1452 bio->bi_end_io = submit_bio_wait_endio;1453 bio->bi_opf |= REQ_SYNC;1454 submit_bio(bio);1455 blk_wait_io(&done);1456 1457 return blk_status_to_errno(bio->bi_status);1458}1459EXPORT_SYMBOL(submit_bio_wait);1460 1461static void bio_wait_end_io(struct bio *bio)1462{1463 complete(bio->bi_private);1464 bio_put(bio);1465}1466 1467/*1468 * bio_await_chain - ends @bio and waits for every chained bio to complete1469 */1470void bio_await_chain(struct bio *bio)1471{1472 DECLARE_COMPLETION_ONSTACK_MAP(done,1473 bio->bi_bdev->bd_disk->lockdep_map);1474 1475 bio->bi_private = &done;1476 bio->bi_end_io = bio_wait_end_io;1477 bio_endio(bio);1478 blk_wait_io(&done);1479}1480 1481void __bio_advance(struct bio *bio, unsigned bytes)1482{1483 if (bio_integrity(bio))1484 bio_integrity_advance(bio, bytes);1485 1486 bio_crypt_advance(bio, bytes);1487 bio_advance_iter(bio, &bio->bi_iter, bytes);1488}1489EXPORT_SYMBOL(__bio_advance);1490 1491void bio_copy_data_iter(struct bio *dst, struct bvec_iter *dst_iter,1492 struct bio *src, struct bvec_iter *src_iter)1493{1494 while (src_iter->bi_size && dst_iter->bi_size) {1495 struct bio_vec src_bv = bio_iter_iovec(src, *src_iter);1496 struct bio_vec dst_bv = bio_iter_iovec(dst, *dst_iter);1497 unsigned int bytes = min(src_bv.bv_len, dst_bv.bv_len);1498 void *src_buf = bvec_kmap_local(&src_bv);1499 void *dst_buf = bvec_kmap_local(&dst_bv);1500 1501 memcpy(dst_buf, src_buf, bytes);1502 1503 kunmap_local(dst_buf);1504 kunmap_local(src_buf);1505 1506 bio_advance_iter_single(src, src_iter, bytes);1507 bio_advance_iter_single(dst, dst_iter, bytes);1508 }1509}1510EXPORT_SYMBOL(bio_copy_data_iter);1511 1512/**1513 * bio_copy_data - copy contents of data buffers from one bio to another1514 * @src: source bio1515 * @dst: destination bio1516 *1517 * Stops when it reaches the end of either @src or @dst - that is, copies1518 * min(src->bi_size, dst->bi_size) bytes (or the equivalent for lists of bios).1519 */1520void bio_copy_data(struct bio *dst, struct bio *src)1521{1522 struct bvec_iter src_iter = src->bi_iter;1523 struct bvec_iter dst_iter = dst->bi_iter;1524 1525 bio_copy_data_iter(dst, &dst_iter, src, &src_iter);1526}1527EXPORT_SYMBOL(bio_copy_data);1528 1529void bio_free_pages(struct bio *bio)1530{1531 struct bio_vec *bvec;1532 struct bvec_iter_all iter_all;1533 1534 bio_for_each_segment_all(bvec, bio, iter_all)1535 __free_page(bvec->bv_page);1536}1537EXPORT_SYMBOL(bio_free_pages);1538 1539/*1540 * bio_set_pages_dirty() and bio_check_pages_dirty() are support functions1541 * for performing direct-IO in BIOs.1542 *1543 * The problem is that we cannot run folio_mark_dirty() from interrupt context1544 * because the required locks are not interrupt-safe. So what we can do is to1545 * mark the pages dirty _before_ performing IO. And in interrupt context,1546 * check that the pages are still dirty. If so, fine. If not, redirty them1547 * in process context.1548 *1549 * Note that this code is very hard to test under normal circumstances because1550 * direct-io pins the pages with get_user_pages(). This makes1551 * is_page_cache_freeable return false, and the VM will not clean the pages.1552 * But other code (eg, flusher threads) could clean the pages if they are mapped1553 * pagecache.1554 *1555 * Simply disabling the call to bio_set_pages_dirty() is a good way to test the1556 * deferred bio dirtying paths.1557 */1558 1559/*1560 * bio_set_pages_dirty() will mark all the bio's pages as dirty.1561 */1562void bio_set_pages_dirty(struct bio *bio)1563{1564 struct folio_iter fi;1565 1566 bio_for_each_folio_all(fi, bio) {1567 folio_lock(fi.folio);1568 folio_mark_dirty(fi.folio);1569 folio_unlock(fi.folio);1570 }1571}1572EXPORT_SYMBOL_GPL(bio_set_pages_dirty);1573 1574/*1575 * bio_check_pages_dirty() will check that all the BIO's pages are still dirty.1576 * If they are, then fine. If, however, some pages are clean then they must1577 * have been written out during the direct-IO read. So we take another ref on1578 * the BIO and re-dirty the pages in process context.1579 *1580 * It is expected that bio_check_pages_dirty() will wholly own the BIO from1581 * here on. It will unpin each page and will run one bio_put() against the1582 * BIO.1583 */1584 1585static void bio_dirty_fn(struct work_struct *work);1586 1587static DECLARE_WORK(bio_dirty_work, bio_dirty_fn);1588static DEFINE_SPINLOCK(bio_dirty_lock);1589static struct bio *bio_dirty_list;1590 1591/*1592 * This runs in process context1593 */1594static void bio_dirty_fn(struct work_struct *work)1595{1596 struct bio *bio, *next;1597 1598 spin_lock_irq(&bio_dirty_lock);1599 next = bio_dirty_list;1600 bio_dirty_list = NULL;1601 spin_unlock_irq(&bio_dirty_lock);1602 1603 while ((bio = next) != NULL) {1604 next = bio->bi_private;1605 1606 bio_release_pages(bio, true);1607 bio_put(bio);1608 }1609}1610 1611void bio_check_pages_dirty(struct bio *bio)1612{1613 struct folio_iter fi;1614 unsigned long flags;1615 1616 bio_for_each_folio_all(fi, bio) {1617 if (!folio_test_dirty(fi.folio))1618 goto defer;1619 }1620 1621 bio_release_pages(bio, false);1622 bio_put(bio);1623 return;1624defer:1625 spin_lock_irqsave(&bio_dirty_lock, flags);1626 bio->bi_private = bio_dirty_list;1627 bio_dirty_list = bio;1628 spin_unlock_irqrestore(&bio_dirty_lock, flags);1629 schedule_work(&bio_dirty_work);1630}1631EXPORT_SYMBOL_GPL(bio_check_pages_dirty);1632 1633static inline bool bio_remaining_done(struct bio *bio)1634{1635 /*1636 * If we're not chaining, then ->__bi_remaining is always 1 and1637 * we always end io on the first invocation.1638 */1639 if (!bio_flagged(bio, BIO_CHAIN))1640 return true;1641 1642 BUG_ON(atomic_read(&bio->__bi_remaining) <= 0);1643 1644 if (atomic_dec_and_test(&bio->__bi_remaining)) {1645 bio_clear_flag(bio, BIO_CHAIN);1646 return true;1647 }1648 1649 return false;1650}1651 1652/**1653 * bio_endio - end I/O on a bio1654 * @bio: bio1655 *1656 * Description:1657 * bio_endio() will end I/O on the whole bio. bio_endio() is the preferred1658 * way to end I/O on a bio. No one should call bi_end_io() directly on a1659 * bio unless they own it and thus know that it has an end_io function.1660 *1661 * bio_endio() can be called several times on a bio that has been chained1662 * using bio_chain(). The ->bi_end_io() function will only be called the1663 * last time.1664 **/1665void bio_endio(struct bio *bio)1666{1667again:1668 if (!bio_remaining_done(bio))1669 return;1670 if (!bio_integrity_endio(bio))1671 return;1672 1673 blk_zone_bio_endio(bio);1674 1675 rq_qos_done_bio(bio);1676 1677 if (bio->bi_bdev && bio_flagged(bio, BIO_TRACE_COMPLETION)) {1678 trace_block_bio_complete(bdev_get_queue(bio->bi_bdev), bio);1679 bio_clear_flag(bio, BIO_TRACE_COMPLETION);1680 }1681 1682 /*1683 * Need to have a real endio function for chained bios, otherwise1684 * various corner cases will break (like stacking block devices that1685 * save/restore bi_end_io) - however, we want to avoid unbounded1686 * recursion and blowing the stack. Tail call optimization would1687 * handle this, but compiling with frame pointers also disables1688 * gcc's sibling call optimization.1689 */1690 if (bio->bi_end_io == bio_chain_endio) {1691 bio = __bio_chain_endio(bio);1692 goto again;1693 }1694 1695#ifdef CONFIG_BLK_CGROUP1696 /*1697 * Release cgroup info. We shouldn't have to do this here, but quite1698 * a few callers of bio_init fail to call bio_uninit, so we cover up1699 * for that here at least for now.1700 */1701 if (bio->bi_blkg) {1702 blkg_put(bio->bi_blkg);1703 bio->bi_blkg = NULL;1704 }1705#endif1706 1707 if (bio->bi_end_io)1708 bio->bi_end_io(bio);1709}1710EXPORT_SYMBOL(bio_endio);1711 1712/**1713 * bio_split - split a bio1714 * @bio: bio to split1715 * @sectors: number of sectors to split from the front of @bio1716 * @gfp: gfp mask1717 * @bs: bio set to allocate from1718 *1719 * Allocates and returns a new bio which represents @sectors from the start of1720 * @bio, and updates @bio to represent the remaining sectors.1721 *1722 * Unless this is a discard request the newly allocated bio will point1723 * to @bio's bi_io_vec. It is the caller's responsibility to ensure that1724 * neither @bio nor @bs are freed before the split bio.1725 */1726struct bio *bio_split(struct bio *bio, int sectors,1727 gfp_t gfp, struct bio_set *bs)1728{1729 struct bio *split;1730 1731 BUG_ON(sectors <= 0);1732 BUG_ON(sectors >= bio_sectors(bio));1733 1734 /* Zone append commands cannot be split */1735 if (WARN_ON_ONCE(bio_op(bio) == REQ_OP_ZONE_APPEND))1736 return NULL;1737 1738 split = bio_alloc_clone(bio->bi_bdev, bio, gfp, bs);1739 if (!split)1740 return NULL;1741 1742 split->bi_iter.bi_size = sectors << 9;1743 1744 if (bio_integrity(split))1745 bio_integrity_trim(split);1746 1747 bio_advance(bio, split->bi_iter.bi_size);1748 1749 if (bio_flagged(bio, BIO_TRACE_COMPLETION))1750 bio_set_flag(split, BIO_TRACE_COMPLETION);1751 1752 return split;1753}1754EXPORT_SYMBOL(bio_split);1755 1756/**1757 * bio_trim - trim a bio1758 * @bio: bio to trim1759 * @offset: number of sectors to trim from the front of @bio1760 * @size: size we want to trim @bio to, in sectors1761 *1762 * This function is typically used for bios that are cloned and submitted1763 * to the underlying device in parts.1764 */1765void bio_trim(struct bio *bio, sector_t offset, sector_t size)1766{1767 if (WARN_ON_ONCE(offset > BIO_MAX_SECTORS || size > BIO_MAX_SECTORS ||1768 offset + size > bio_sectors(bio)))1769 return;1770 1771 size <<= 9;1772 if (offset == 0 && size == bio->bi_iter.bi_size)1773 return;1774 1775 bio_advance(bio, offset << 9);1776 bio->bi_iter.bi_size = size;1777 1778 if (bio_integrity(bio))1779 bio_integrity_trim(bio);1780}1781EXPORT_SYMBOL_GPL(bio_trim);1782 1783/*1784 * create memory pools for biovec's in a bio_set.1785 * use the global biovec slabs created for general use.1786 */1787int biovec_init_pool(mempool_t *pool, int pool_entries)1788{1789 struct biovec_slab *bp = bvec_slabs + ARRAY_SIZE(bvec_slabs) - 1;1790 1791 return mempool_init_slab_pool(pool, pool_entries, bp->slab);1792}1793 1794/*1795 * bioset_exit - exit a bioset initialized with bioset_init()1796 *1797 * May be called on a zeroed but uninitialized bioset (i.e. allocated with1798 * kzalloc()).1799 */1800void bioset_exit(struct bio_set *bs)1801{1802 bio_alloc_cache_destroy(bs);1803 if (bs->rescue_workqueue)1804 destroy_workqueue(bs->rescue_workqueue);1805 bs->rescue_workqueue = NULL;1806 1807 mempool_exit(&bs->bio_pool);1808 mempool_exit(&bs->bvec_pool);1809 1810 bioset_integrity_free(bs);1811 if (bs->bio_slab)1812 bio_put_slab(bs);1813 bs->bio_slab = NULL;1814}1815EXPORT_SYMBOL(bioset_exit);1816 1817/**1818 * bioset_init - Initialize a bio_set1819 * @bs: pool to initialize1820 * @pool_size: Number of bio and bio_vecs to cache in the mempool1821 * @front_pad: Number of bytes to allocate in front of the returned bio1822 * @flags: Flags to modify behavior, currently %BIOSET_NEED_BVECS1823 * and %BIOSET_NEED_RESCUER1824 *1825 * Description:1826 * Set up a bio_set to be used with @bio_alloc_bioset. Allows the caller1827 * to ask for a number of bytes to be allocated in front of the bio.1828 * Front pad allocation is useful for embedding the bio inside1829 * another structure, to avoid allocating extra data to go with the bio.1830 * Note that the bio must be embedded at the END of that structure always,1831 * or things will break badly.1832 * If %BIOSET_NEED_BVECS is set in @flags, a separate pool will be allocated1833 * for allocating iovecs. This pool is not needed e.g. for bio_init_clone().1834 * If %BIOSET_NEED_RESCUER is set, a workqueue is created which can be used1835 * to dispatch queued requests when the mempool runs out of space.1836 *1837 */1838int bioset_init(struct bio_set *bs,1839 unsigned int pool_size,1840 unsigned int front_pad,1841 int flags)1842{1843 bs->front_pad = front_pad;1844 if (flags & BIOSET_NEED_BVECS)1845 bs->back_pad = BIO_INLINE_VECS * sizeof(struct bio_vec);1846 else1847 bs->back_pad = 0;1848 1849 spin_lock_init(&bs->rescue_lock);1850 bio_list_init(&bs->rescue_list);1851 INIT_WORK(&bs->rescue_work, bio_alloc_rescue);1852 1853 bs->bio_slab = bio_find_or_create_slab(bs);1854 if (!bs->bio_slab)1855 return -ENOMEM;1856 1857 if (mempool_init_slab_pool(&bs->bio_pool, pool_size, bs->bio_slab))1858 goto bad;1859 1860 if ((flags & BIOSET_NEED_BVECS) &&1861 biovec_init_pool(&bs->bvec_pool, pool_size))1862 goto bad;1863 1864 if (flags & BIOSET_NEED_RESCUER) {1865 bs->rescue_workqueue = alloc_workqueue("bioset",1866 WQ_MEM_RECLAIM, 0);1867 if (!bs->rescue_workqueue)1868 goto bad;1869 }1870 if (flags & BIOSET_PERCPU_CACHE) {1871 bs->cache = alloc_percpu(struct bio_alloc_cache);1872 if (!bs->cache)1873 goto bad;1874 cpuhp_state_add_instance_nocalls(CPUHP_BIO_DEAD, &bs->cpuhp_dead);1875 }1876 1877 return 0;1878bad:1879 bioset_exit(bs);1880 return -ENOMEM;1881}1882EXPORT_SYMBOL(bioset_init);1883 1884static int __init init_bio(void)1885{1886 int i;1887 1888 BUILD_BUG_ON(BIO_FLAG_LAST > 8 * sizeof_field(struct bio, bi_flags));1889 1890 bio_integrity_init();1891 1892 for (i = 0; i < ARRAY_SIZE(bvec_slabs); i++) {1893 struct biovec_slab *bvs = bvec_slabs + i;1894 1895 bvs->slab = kmem_cache_create(bvs->name,1896 bvs->nr_vecs * sizeof(struct bio_vec), 0,1897 SLAB_HWCACHE_ALIGN | SLAB_PANIC, NULL);1898 }1899 1900 cpuhp_setup_state_multi(CPUHP_BIO_DEAD, "block/bio:dead", NULL,1901 bio_cpu_dead);1902 1903 if (bioset_init(&fs_bio_set, BIO_POOL_SIZE, 0,1904 BIOSET_NEED_BVECS | BIOSET_PERCPU_CACHE))1905 panic("bio: can't allocate bios\n");1906 1907 if (bioset_integrity_create(&fs_bio_set, BIO_POOL_SIZE))1908 panic("bio: can't create integrity pool\n");1909 1910 return 0;1911}1912subsys_initcall(init_bio);1913