diff options
Diffstat (limited to 'block/bio.c')
| -rw-r--r-- | block/bio.c | 1809 |
1 files changed, 1809 insertions, 0 deletions
diff --git a/block/bio.c b/block/bio.c new file mode 100644 index 000000000..5eba53ca9 --- /dev/null +++ b/block/bio.c @@ -0,0 +1,1809 @@ +// SPDX-License-Identifier: GPL-2.0 +/* + * Copyright (C) 2001 Jens Axboe <axboe@kernel.dk> + */ +#include <linux/mm.h> +#include <linux/swap.h> +#include <linux/bio.h> +#include <linux/blkdev.h> +#include <linux/uio.h> +#include <linux/iocontext.h> +#include <linux/slab.h> +#include <linux/init.h> +#include <linux/kernel.h> +#include <linux/export.h> +#include <linux/mempool.h> +#include <linux/workqueue.h> +#include <linux/cgroup.h> +#include <linux/highmem.h> +#include <linux/sched/sysctl.h> +#include <linux/blk-crypto.h> +#include <linux/xarray.h> + +#include <trace/events/block.h> +#include "blk.h" +#include "blk-rq-qos.h" +#include "blk-cgroup.h" + +#define ALLOC_CACHE_THRESHOLD 16 +#define ALLOC_CACHE_MAX 256 + +struct bio_alloc_cache { + struct bio *free_list; + struct bio *free_list_irq; + unsigned int nr; + unsigned int nr_irq; +}; + +static struct biovec_slab { + int nr_vecs; + char *name; + struct kmem_cache *slab; +} bvec_slabs[] __read_mostly = { + { .nr_vecs = 16, .name = "biovec-16" }, + { .nr_vecs = 64, .name = "biovec-64" }, + { .nr_vecs = 128, .name = "biovec-128" }, + { .nr_vecs = BIO_MAX_VECS, .name = "biovec-max" }, +}; + +static struct biovec_slab *biovec_slab(unsigned short nr_vecs) +{ + switch (nr_vecs) { + /* smaller bios use inline vecs */ + case 5 ... 16: + return &bvec_slabs[0]; + case 17 ... 64: + return &bvec_slabs[1]; + case 65 ... 128: + return &bvec_slabs[2]; + case 129 ... BIO_MAX_VECS: + return &bvec_slabs[3]; + default: + BUG(); + return NULL; + } +} + +/* + * fs_bio_set is the bio_set containing bio and iovec memory pools used by + * IO code that does not need private memory pools. + */ +struct bio_set fs_bio_set; +EXPORT_SYMBOL(fs_bio_set); + +/* + * Our slab pool management + */ +struct bio_slab { + struct kmem_cache *slab; + unsigned int slab_ref; + unsigned int slab_size; + char name[8]; +}; +static DEFINE_MUTEX(bio_slab_lock); +static DEFINE_XARRAY(bio_slabs); + +static struct bio_slab *create_bio_slab(unsigned int size) +{ + struct bio_slab *bslab = kzalloc(sizeof(*bslab), GFP_KERNEL); + + if (!bslab) + return NULL; + + snprintf(bslab->name, sizeof(bslab->name), "bio-%d", size); + bslab->slab = kmem_cache_create(bslab->name, size, + ARCH_KMALLOC_MINALIGN, + SLAB_HWCACHE_ALIGN | SLAB_TYPESAFE_BY_RCU, NULL); + if (!bslab->slab) + goto fail_alloc_slab; + + bslab->slab_ref = 1; + bslab->slab_size = size; + + if (!xa_err(xa_store(&bio_slabs, size, bslab, GFP_KERNEL))) + return bslab; + + kmem_cache_destroy(bslab->slab); + +fail_alloc_slab: + kfree(bslab); + return NULL; +} + +static inline unsigned int bs_bio_slab_size(struct bio_set *bs) +{ + return bs->front_pad + sizeof(struct bio) + bs->back_pad; +} + +static struct kmem_cache *bio_find_or_create_slab(struct bio_set *bs) +{ + unsigned int size = bs_bio_slab_size(bs); + struct bio_slab *bslab; + + mutex_lock(&bio_slab_lock); + bslab = xa_load(&bio_slabs, size); + if (bslab) + bslab->slab_ref++; + else + bslab = create_bio_slab(size); + mutex_unlock(&bio_slab_lock); + + if (bslab) + return bslab->slab; + return NULL; +} + +static void bio_put_slab(struct bio_set *bs) +{ + struct bio_slab *bslab = NULL; + unsigned int slab_size = bs_bio_slab_size(bs); + + mutex_lock(&bio_slab_lock); + + bslab = xa_load(&bio_slabs, slab_size); + if (WARN(!bslab, KERN_ERR "bio: unable to find slab!\n")) + goto out; + + WARN_ON_ONCE(bslab->slab != bs->bio_slab); + + WARN_ON(!bslab->slab_ref); + + if (--bslab->slab_ref) + goto out; + + xa_erase(&bio_slabs, slab_size); + + kmem_cache_destroy(bslab->slab); + kfree(bslab); + +out: + mutex_unlock(&bio_slab_lock); +} + +void bvec_free(mempool_t *pool, struct bio_vec *bv, unsigned short nr_vecs) +{ + BUG_ON(nr_vecs > BIO_MAX_VECS); + + if (nr_vecs == BIO_MAX_VECS) + mempool_free(bv, pool); + else if (nr_vecs > BIO_INLINE_VECS) + kmem_cache_free(biovec_slab(nr_vecs)->slab, bv); +} + +/* + * Make the first allocation restricted and don't dump info on allocation + * failures, since we'll fall back to the mempool in case of failure. + */ +static inline gfp_t bvec_alloc_gfp(gfp_t gfp) +{ + return (gfp & ~(__GFP_DIRECT_RECLAIM | __GFP_IO)) | + __GFP_NOMEMALLOC | __GFP_NORETRY | __GFP_NOWARN; +} + +struct bio_vec *bvec_alloc(mempool_t *pool, unsigned short *nr_vecs, + gfp_t gfp_mask) +{ + struct biovec_slab *bvs = biovec_slab(*nr_vecs); + + if (WARN_ON_ONCE(!bvs)) + return NULL; + + /* + * Upgrade the nr_vecs request to take full advantage of the allocation. + * We also rely on this in the bvec_free path. + */ + *nr_vecs = bvs->nr_vecs; + + /* + * Try a slab allocation first for all smaller allocations. If that + * fails and __GFP_DIRECT_RECLAIM is set retry with the mempool. + * The mempool is sized to handle up to BIO_MAX_VECS entries. + */ + if (*nr_vecs < BIO_MAX_VECS) { + struct bio_vec *bvl; + + bvl = kmem_cache_alloc(bvs->slab, bvec_alloc_gfp(gfp_mask)); + if (likely(bvl) || !(gfp_mask & __GFP_DIRECT_RECLAIM)) + return bvl; + *nr_vecs = BIO_MAX_VECS; + } + + return mempool_alloc(pool, gfp_mask); +} + +void bio_uninit(struct bio *bio) +{ +#ifdef CONFIG_BLK_CGROUP + if (bio->bi_blkg) { + blkg_put(bio->bi_blkg); + bio->bi_blkg = NULL; + } +#endif + if (bio_integrity(bio)) + bio_integrity_free(bio); + + bio_crypt_free_ctx(bio); +} +EXPORT_SYMBOL(bio_uninit); + +static void bio_free(struct bio *bio) +{ + struct bio_set *bs = bio->bi_pool; + void *p = bio; + + WARN_ON_ONCE(!bs); + + bio_uninit(bio); + bvec_free(&bs->bvec_pool, bio->bi_io_vec, bio->bi_max_vecs); + mempool_free(p - bs->front_pad, &bs->bio_pool); +} + +/* + * Users of this function have their own bio allocation. Subsequently, + * they must remember to pair any call to bio_init() with bio_uninit() + * when IO has completed, or when the bio is released. + */ +void bio_init(struct bio *bio, struct block_device *bdev, struct bio_vec *table, + unsigned short max_vecs, blk_opf_t opf) +{ + bio->bi_next = NULL; + bio->bi_bdev = bdev; + bio->bi_opf = opf; + bio->bi_flags = 0; + bio->bi_ioprio = 0; + bio->bi_status = 0; + bio->bi_iter.bi_sector = 0; + bio->bi_iter.bi_size = 0; + bio->bi_iter.bi_idx = 0; + bio->bi_iter.bi_bvec_done = 0; + bio->bi_end_io = NULL; + bio->bi_private = NULL; +#ifdef CONFIG_BLK_CGROUP + bio->bi_blkg = NULL; + bio->bi_issue.value = 0; + if (bdev) + bio_associate_blkg(bio); +#ifdef CONFIG_BLK_CGROUP_IOCOST + bio->bi_iocost_cost = 0; +#endif +#endif +#ifdef CONFIG_BLK_INLINE_ENCRYPTION + bio->bi_crypt_context = NULL; +#endif +#ifdef CONFIG_BLK_DEV_INTEGRITY + bio->bi_integrity = NULL; +#endif + bio->bi_vcnt = 0; + + atomic_set(&bio->__bi_remaining, 1); + atomic_set(&bio->__bi_cnt, 1); + bio->bi_cookie = BLK_QC_T_NONE; + + bio->bi_max_vecs = max_vecs; + bio->bi_io_vec = table; + bio->bi_pool = NULL; +} +EXPORT_SYMBOL(bio_init); + +/** + * bio_reset - reinitialize a bio + * @bio: bio to reset + * @bdev: block device to use the bio for + * @opf: operation and flags for bio + * + * Description: + * After calling bio_reset(), @bio will be in the same state as a freshly + * allocated bio returned bio bio_alloc_bioset() - the only fields that are + * preserved are the ones that are initialized by bio_alloc_bioset(). See + * comment in struct bio. + */ +void bio_reset(struct bio *bio, struct block_device *bdev, blk_opf_t opf) +{ + bio_uninit(bio); + memset(bio, 0, BIO_RESET_BYTES); + atomic_set(&bio->__bi_remaining, 1); + bio->bi_bdev = bdev; + if (bio->bi_bdev) + bio_associate_blkg(bio); + bio->bi_opf = opf; +} +EXPORT_SYMBOL(bio_reset); + +static struct bio *__bio_chain_endio(struct bio *bio) +{ + struct bio *parent = bio->bi_private; + + if (bio->bi_status && !parent->bi_status) + parent->bi_status = bio->bi_status; + bio_put(bio); + return parent; +} + +static void bio_chain_endio(struct bio *bio) +{ + bio_endio(__bio_chain_endio(bio)); +} + +/** + * bio_chain - chain bio completions + * @bio: the target bio + * @parent: the parent bio of @bio + * + * The caller won't have a bi_end_io called when @bio completes - instead, + * @parent's bi_end_io won't be called until both @parent and @bio have + * completed; the chained bio will also be freed when it completes. + * + * The caller must not set bi_private or bi_end_io in @bio. + */ +void bio_chain(struct bio *bio, struct bio *parent) +{ + BUG_ON(bio->bi_private || bio->bi_end_io); + + bio->bi_private = parent; + bio->bi_end_io = bio_chain_endio; + bio_inc_remaining(parent); +} +EXPORT_SYMBOL(bio_chain); + +struct bio *blk_next_bio(struct bio *bio, struct block_device *bdev, + unsigned int nr_pages, blk_opf_t opf, gfp_t gfp) +{ + struct bio *new = bio_alloc(bdev, nr_pages, opf, gfp); + + if (bio) { + bio_chain(bio, new); + submit_bio(bio); + } + + return new; +} +EXPORT_SYMBOL_GPL(blk_next_bio); + +static void bio_alloc_rescue(struct work_struct *work) +{ + struct bio_set *bs = container_of(work, struct bio_set, rescue_work); + struct bio *bio; + + while (1) { + spin_lock(&bs->rescue_lock); + bio = bio_list_pop(&bs->rescue_list); + spin_unlock(&bs->rescue_lock); + + if (!bio) + break; + + submit_bio_noacct(bio); + } +} + +static void punt_bios_to_rescuer(struct bio_set *bs) +{ + struct bio_list punt, nopunt; + struct bio *bio; + + if (WARN_ON_ONCE(!bs->rescue_workqueue)) + return; + /* + * In order to guarantee forward progress we must punt only bios that + * were allocated from this bio_set; otherwise, if there was a bio on + * there for a stacking driver higher up in the stack, processing it + * could require allocating bios from this bio_set, and doing that from + * our own rescuer would be bad. + * + * Since bio lists are singly linked, pop them all instead of trying to + * remove from the middle of the list: + */ + + bio_list_init(&punt); + bio_list_init(&nopunt); + + while ((bio = bio_list_pop(¤t->bio_list[0]))) + bio_list_add(bio->bi_pool == bs ? &punt : &nopunt, bio); + current->bio_list[0] = nopunt; + + bio_list_init(&nopunt); + while ((bio = bio_list_pop(¤t->bio_list[1]))) + bio_list_add(bio->bi_pool == bs ? &punt : &nopunt, bio); + current->bio_list[1] = nopunt; + + spin_lock(&bs->rescue_lock); + bio_list_merge(&bs->rescue_list, &punt); + spin_unlock(&bs->rescue_lock); + + queue_work(bs->rescue_workqueue, &bs->rescue_work); +} + +static void bio_alloc_irq_cache_splice(struct bio_alloc_cache *cache) +{ + unsigned long flags; + + /* cache->free_list must be empty */ + if (WARN_ON_ONCE(cache->free_list)) + return; + + local_irq_save(flags); + cache->free_list = cache->free_list_irq; + cache->free_list_irq = NULL; + cache->nr += cache->nr_irq; + cache->nr_irq = 0; + local_irq_restore(flags); +} + +static struct bio *bio_alloc_percpu_cache(struct block_device *bdev, + unsigned short nr_vecs, blk_opf_t opf, gfp_t gfp, + struct bio_set *bs) +{ + struct bio_alloc_cache *cache; + struct bio *bio; + + cache = per_cpu_ptr(bs->cache, get_cpu()); + if (!cache->free_list) { + if (READ_ONCE(cache->nr_irq) >= ALLOC_CACHE_THRESHOLD) + bio_alloc_irq_cache_splice(cache); + if (!cache->free_list) { + put_cpu(); + return NULL; + } + } + bio = cache->free_list; + cache->free_list = bio->bi_next; + cache->nr--; + put_cpu(); + + bio_init(bio, bdev, nr_vecs ? bio->bi_inline_vecs : NULL, nr_vecs, opf); + bio->bi_pool = bs; + return bio; +} + +/** + * bio_alloc_bioset - allocate a bio for I/O + * @bdev: block device to allocate the bio for (can be %NULL) + * @nr_vecs: number of bvecs to pre-allocate + * @opf: operation and flags for bio + * @gfp_mask: the GFP_* mask given to the slab allocator + * @bs: the bio_set to allocate from. + * + * Allocate a bio from the mempools in @bs. + * + * If %__GFP_DIRECT_RECLAIM is set then bio_alloc will always be able to + * allocate a bio. This is due to the mempool guarantees. To make this work, + * callers must never allocate more than 1 bio at a time from the general pool. + * Callers that need to allocate more than 1 bio must always submit the + * previously allocated bio for IO before attempting to allocate a new one. + * Failure to do so can cause deadlocks under memory pressure. + * + * Note that when running under submit_bio_noacct() (i.e. any block driver), + * bios are not submitted until after you return - see the code in + * submit_bio_noacct() that converts recursion into iteration, to prevent + * stack overflows. + * + * This would normally mean allocating multiple bios under submit_bio_noacct() + * would be susceptible to deadlocks, but we have + * deadlock avoidance code that resubmits any blocked bios from a rescuer + * thread. + * + * However, we do not guarantee forward progress for allocations from other + * mempools. Doing multiple allocations from the same mempool under + * submit_bio_noacct() should be avoided - instead, use bio_set's front_pad + * for per bio allocations. + * + * Returns: Pointer to new bio on success, NULL on failure. + */ +struct bio *bio_alloc_bioset(struct block_device *bdev, unsigned short nr_vecs, + blk_opf_t opf, gfp_t gfp_mask, + struct bio_set *bs) +{ + gfp_t saved_gfp = gfp_mask; + struct bio *bio; + void *p; + + /* should not use nobvec bioset for nr_vecs > 0 */ + if (WARN_ON_ONCE(!mempool_initialized(&bs->bvec_pool) && nr_vecs > 0)) + return NULL; + + if (opf & REQ_ALLOC_CACHE) { + if (bs->cache && nr_vecs <= BIO_INLINE_VECS) { + bio = bio_alloc_percpu_cache(bdev, nr_vecs, opf, + gfp_mask, bs); + if (bio) + return bio; + /* + * No cached bio available, bio returned below marked with + * REQ_ALLOC_CACHE to particpate in per-cpu alloc cache. + */ + } else { + opf &= ~REQ_ALLOC_CACHE; + } + } + + /* + * submit_bio_noacct() converts recursion to iteration; this means if + * we're running beneath it, any bios we allocate and submit will not be + * submitted (and thus freed) until after we return. + * + * This exposes us to a potential deadlock if we allocate multiple bios + * from the same bio_set() while running underneath submit_bio_noacct(). + * If we were to allocate multiple bios (say a stacking block driver + * that was splitting bios), we would deadlock if we exhausted the + * mempool's reserve. + * + * We solve this, and guarantee forward progress, with a rescuer + * workqueue per bio_set. If we go to allocate and there are bios on + * current->bio_list, we first try the allocation without + * __GFP_DIRECT_RECLAIM; if that fails, we punt those bios we would be + * blocking to the rescuer workqueue before we retry with the original + * gfp_flags. + */ + if (current->bio_list && + (!bio_list_empty(¤t->bio_list[0]) || + !bio_list_empty(¤t->bio_list[1])) && + bs->rescue_workqueue) + gfp_mask &= ~__GFP_DIRECT_RECLAIM; + + p = mempool_alloc(&bs->bio_pool, gfp_mask); + if (!p && gfp_mask != saved_gfp) { + punt_bios_to_rescuer(bs); + gfp_mask = saved_gfp; + p = mempool_alloc(&bs->bio_pool, gfp_mask); + } + if (unlikely(!p)) + return NULL; + if (!mempool_is_saturated(&bs->bio_pool)) + opf &= ~REQ_ALLOC_CACHE; + + bio = p + bs->front_pad; + if (nr_vecs > BIO_INLINE_VECS) { + struct bio_vec *bvl = NULL; + + bvl = bvec_alloc(&bs->bvec_pool, &nr_vecs, gfp_mask); + if (!bvl && gfp_mask != saved_gfp) { + punt_bios_to_rescuer(bs); + gfp_mask = saved_gfp; + bvl = bvec_alloc(&bs->bvec_pool, &nr_vecs, gfp_mask); + } + if (unlikely(!bvl)) + goto err_free; + + bio_init(bio, bdev, bvl, nr_vecs, opf); + } else if (nr_vecs) { + bio_init(bio, bdev, bio->bi_inline_vecs, BIO_INLINE_VECS, opf); + } else { + bio_init(bio, bdev, NULL, 0, opf); + } + + bio->bi_pool = bs; + return bio; + +err_free: + mempool_free(p, &bs->bio_pool); + return NULL; +} +EXPORT_SYMBOL(bio_alloc_bioset); + +/** + * bio_kmalloc - kmalloc a bio + * @nr_vecs: number of bio_vecs to allocate + * @gfp_mask: the GFP_* mask given to the slab allocator + * + * Use kmalloc to allocate a bio (including bvecs). The bio must be initialized + * using bio_init() before use. To free a bio returned from this function use + * kfree() after calling bio_uninit(). A bio returned from this function can + * be reused by calling bio_uninit() before calling bio_init() again. + * + * Note that unlike bio_alloc() or bio_alloc_bioset() allocations from this + * function are not backed by a mempool can fail. Do not use this function + * for allocations in the file system I/O path. + * + * Returns: Pointer to new bio on success, NULL on failure. + */ +struct bio *bio_kmalloc(unsigned short nr_vecs, gfp_t gfp_mask) +{ + struct bio *bio; + + if (nr_vecs > UIO_MAXIOV) + return NULL; + return kmalloc(struct_size(bio, bi_inline_vecs, nr_vecs), gfp_mask); +} +EXPORT_SYMBOL(bio_kmalloc); + +void zero_fill_bio_iter(struct bio *bio, struct bvec_iter start) +{ + struct bio_vec bv; + struct bvec_iter iter; + + __bio_for_each_segment(bv, bio, iter, start) + memzero_bvec(&bv); +} +EXPORT_SYMBOL(zero_fill_bio_iter); + +/** + * bio_truncate - truncate the bio to small size of @new_size + * @bio: the bio to be truncated + * @new_size: new size for truncating the bio + * + * Description: + * Truncate the bio to new size of @new_size. If bio_op(bio) is + * REQ_OP_READ, zero the truncated part. This function should only + * be used for handling corner cases, such as bio eod. + */ +static void bio_truncate(struct bio *bio, unsigned new_size) +{ + struct bio_vec bv; + struct bvec_iter iter; + unsigned int done = 0; + bool truncated = false; + + if (new_size >= bio->bi_iter.bi_size) + return; + + if (bio_op(bio) != REQ_OP_READ) + goto exit; + + bio_for_each_segment(bv, bio, iter) { + if (done + bv.bv_len > new_size) { + unsigned offset; + + if (!truncated) + offset = new_size - done; + else + offset = 0; + zero_user(bv.bv_page, bv.bv_offset + offset, + bv.bv_len - offset); + truncated = true; + } + done += bv.bv_len; + } + + exit: + /* + * Don't touch bvec table here and make it really immutable, since + * fs bio user has to retrieve all pages via bio_for_each_segment_all + * in its .end_bio() callback. + * + * It is enough to truncate bio by updating .bi_size since we can make + * correct bvec with the updated .bi_size for drivers. + */ + bio->bi_iter.bi_size = new_size; +} + +/** + * guard_bio_eod - truncate a BIO to fit the block device + * @bio: bio to truncate + * + * This allows us to do IO even on the odd last sectors of a device, even if the + * block size is some multiple of the physical sector size. + * + * We'll just truncate the bio to the size of the device, and clear the end of + * the buffer head manually. Truly out-of-range accesses will turn into actual + * I/O errors, this only handles the "we need to be able to do I/O at the final + * sector" case. + */ +void guard_bio_eod(struct bio *bio) +{ + sector_t maxsector = bdev_nr_sectors(bio->bi_bdev); + + if (!maxsector) + return; + + /* + * If the *whole* IO is past the end of the device, + * let it through, and the IO layer will turn it into + * an EIO. + */ + if (unlikely(bio->bi_iter.bi_sector >= maxsector)) + return; + + maxsector -= bio->bi_iter.bi_sector; + if (likely((bio->bi_iter.bi_size >> 9) <= maxsector)) + return; + + bio_truncate(bio, maxsector << 9); +} + +static int __bio_alloc_cache_prune(struct bio_alloc_cache *cache, + unsigned int nr) +{ + unsigned int i = 0; + struct bio *bio; + + while ((bio = cache->free_list) != NULL) { + cache->free_list = bio->bi_next; + cache->nr--; + bio_free(bio); + if (++i == nr) + break; + } + return i; +} + +static void bio_alloc_cache_prune(struct bio_alloc_cache *cache, + unsigned int nr) +{ + nr -= __bio_alloc_cache_prune(cache, nr); + if (!READ_ONCE(cache->free_list)) { + bio_alloc_irq_cache_splice(cache); + __bio_alloc_cache_prune(cache, nr); + } +} + +static int bio_cpu_dead(unsigned int cpu, struct hlist_node *node) +{ + struct bio_set *bs; + + bs = hlist_entry_safe(node, struct bio_set, cpuhp_dead); + if (bs->cache) { + struct bio_alloc_cache *cache = per_cpu_ptr(bs->cache, cpu); + + bio_alloc_cache_prune(cache, -1U); + } + return 0; +} + +static void bio_alloc_cache_destroy(struct bio_set *bs) +{ + int cpu; + + if (!bs->cache) + return; + + cpuhp_state_remove_instance_nocalls(CPUHP_BIO_DEAD, &bs->cpuhp_dead); + for_each_possible_cpu(cpu) { + struct bio_alloc_cache *cache; + + cache = per_cpu_ptr(bs->cache, cpu); + bio_alloc_cache_prune(cache, -1U); + } + free_percpu(bs->cache); + bs->cache = NULL; +} + +static inline void bio_put_percpu_cache(struct bio *bio) +{ + struct bio_alloc_cache *cache; + + cache = per_cpu_ptr(bio->bi_pool->cache, get_cpu()); + if (READ_ONCE(cache->nr_irq) + cache->nr > ALLOC_CACHE_MAX) { + put_cpu(); + bio_free(bio); + return; + } + + bio_uninit(bio); + + if ((bio->bi_opf & REQ_POLLED) && !WARN_ON_ONCE(in_interrupt())) { + bio->bi_next = cache->free_list; + bio->bi_bdev = NULL; + cache->free_list = bio; + cache->nr++; + } else { + unsigned long flags; + + local_irq_save(flags); + bio->bi_next = cache->free_list_irq; + cache->free_list_irq = bio; + cache->nr_irq++; + local_irq_restore(flags); + } + put_cpu(); +} + +/** + * bio_put - release a reference to a bio + * @bio: bio to release reference to + * + * Description: + * Put a reference to a &struct bio, either one you have gotten with + * bio_alloc, bio_get or bio_clone_*. The last put of a bio will free it. + **/ +void bio_put(struct bio *bio) +{ + if (unlikely(bio_flagged(bio, BIO_REFFED))) { + BUG_ON(!atomic_read(&bio->__bi_cnt)); + if (!atomic_dec_and_test(&bio->__bi_cnt)) + return; + } + if (bio->bi_opf & REQ_ALLOC_CACHE) + bio_put_percpu_cache(bio); + else + bio_free(bio); +} +EXPORT_SYMBOL(bio_put); + +static int __bio_clone(struct bio *bio, struct bio *bio_src, gfp_t gfp) +{ + bio_set_flag(bio, BIO_CLONED); + bio->bi_ioprio = bio_src->bi_ioprio; + bio->bi_iter = bio_src->bi_iter; + + if (bio->bi_bdev) { + if (bio->bi_bdev == bio_src->bi_bdev && + bio_flagged(bio_src, BIO_REMAPPED)) + bio_set_flag(bio, BIO_REMAPPED); + bio_clone_blkg_association(bio, bio_src); + } + + if (bio_crypt_clone(bio, bio_src, gfp) < 0) + return -ENOMEM; + if (bio_integrity(bio_src) && + bio_integrity_clone(bio, bio_src, gfp) < 0) + return -ENOMEM; + return 0; +} + +/** + * bio_alloc_clone - clone a bio that shares the original bio's biovec + * @bdev: block_device to clone onto + * @bio_src: bio to clone from + * @gfp: allocation priority + * @bs: bio_set to allocate from + * + * Allocate a new bio that is a clone of @bio_src. The caller owns the returned + * bio, but not the actual data it points to. + * + * The caller must ensure that the return bio is not freed before @bio_src. + */ +struct bio *bio_alloc_clone(struct block_device *bdev, struct bio *bio_src, + gfp_t gfp, struct bio_set *bs) +{ + struct bio *bio; + + bio = bio_alloc_bioset(bdev, 0, bio_src->bi_opf, gfp, bs); + if (!bio) + return NULL; + + if (__bio_clone(bio, bio_src, gfp) < 0) { + bio_put(bio); + return NULL; + } + bio->bi_io_vec = bio_src->bi_io_vec; + + return bio; +} +EXPORT_SYMBOL(bio_alloc_clone); + +/** + * bio_init_clone - clone a bio that shares the original bio's biovec + * @bdev: block_device to clone onto + * @bio: bio to clone into + * @bio_src: bio to clone from + * @gfp: allocation priority + * + * Initialize a new bio in caller provided memory that is a clone of @bio_src. + * The caller owns the returned bio, but not the actual data it points to. + * + * The caller must ensure that @bio_src is not freed before @bio. + */ +int bio_init_clone(struct block_device *bdev, struct bio *bio, + struct bio *bio_src, gfp_t gfp) +{ + int ret; + + bio_init(bio, bdev, bio_src->bi_io_vec, 0, bio_src->bi_opf); + ret = __bio_clone(bio, bio_src, gfp); + if (ret) + bio_uninit(bio); + return ret; +} +EXPORT_SYMBOL(bio_init_clone); + +/** + * bio_full - check if the bio is full + * @bio: bio to check + * @len: length of one segment to be added + * + * Return true if @bio is full and one segment with @len bytes can't be + * added to the bio, otherwise return false + */ +static inline bool bio_full(struct bio *bio, unsigned len) +{ + if (bio->bi_vcnt >= bio->bi_max_vecs) + return true; + if (bio->bi_iter.bi_size > UINT_MAX - len) + return true; + return false; +} + +static bool bvec_try_merge_page(struct bio_vec *bv, struct page *page, + unsigned int len, unsigned int off, bool *same_page) +{ + size_t bv_end = bv->bv_offset + bv->bv_len; + phys_addr_t vec_end_addr = page_to_phys(bv->bv_page) + bv_end - 1; + phys_addr_t page_addr = page_to_phys(page); + + if (vec_end_addr + 1 != page_addr + off) + return false; + if (xen_domain() && !xen_biovec_phys_mergeable(bv, page)) + return false; + if (!zone_device_pages_have_same_pgmap(bv->bv_page, page)) + return false; + + *same_page = ((vec_end_addr & PAGE_MASK) == page_addr); + if (!*same_page) { + if (IS_ENABLED(CONFIG_KMSAN)) + return false; + if (bv->bv_page + bv_end / PAGE_SIZE != page + off / PAGE_SIZE) + return false; + } + + bv->bv_len += len; + return true; +} + +/* + * Try to merge a page into a segment, while obeying the hardware segment + * size limit. This is not for normal read/write bios, but for passthrough + * or Zone Append operations that we can't split. + */ +bool bvec_try_merge_hw_page(struct request_queue *q, struct bio_vec *bv, + struct page *page, unsigned len, unsigned offset, + bool *same_page) +{ + unsigned long mask = queue_segment_boundary(q); + phys_addr_t addr1 = page_to_phys(bv->bv_page) + bv->bv_offset; + phys_addr_t addr2 = page_to_phys(page) + offset + len - 1; + + if ((addr1 | mask) != (addr2 | mask)) + return false; + if (bv->bv_len + len > queue_max_segment_size(q)) + return false; + return bvec_try_merge_page(bv, page, len, offset, same_page); +} + +/** + * bio_add_hw_page - attempt to add a page to a bio with hw constraints + * @q: the target queue + * @bio: destination bio + * @page: page to add + * @len: vec entry length + * @offset: vec entry offset + * @max_sectors: maximum number of sectors that can be added + * @same_page: return if the segment has been merged inside the same page + * + * Add a page to a bio while respecting the hardware max_sectors, max_segment + * and gap limitations. + */ +int bio_add_hw_page(struct request_queue *q, struct bio *bio, + struct page *page, unsigned int len, unsigned int offset, + unsigned int max_sectors, bool *same_page) +{ + if (WARN_ON_ONCE(bio_flagged(bio, BIO_CLONED))) + return 0; + + if (((bio->bi_iter.bi_size + len) >> SECTOR_SHIFT) > max_sectors) + return 0; + + if (bio->bi_vcnt > 0) { + struct bio_vec *bv = &bio->bi_io_vec[bio->bi_vcnt - 1]; + + if (bvec_try_merge_hw_page(q, bv, page, len, offset, + same_page)) { + bio->bi_iter.bi_size += len; + return len; + } + + if (bio->bi_vcnt >= + min(bio->bi_max_vecs, queue_max_segments(q))) + return 0; + + /* + * If the queue doesn't support SG gaps and adding this segment + * would create a gap, disallow it. + */ + if (bvec_gap_to_prev(&q->limits, bv, offset)) + return 0; + } + + bvec_set_page(&bio->bi_io_vec[bio->bi_vcnt], page, len, offset); + bio->bi_vcnt++; + bio->bi_iter.bi_size += len; + return len; +} + +/** + * bio_add_pc_page - attempt to add page to passthrough bio + * @q: the target queue + * @bio: destination bio + * @page: page to add + * @len: vec entry length + * @offset: vec entry offset + * + * Attempt to add a page to the bio_vec maplist. This can fail for a + * number of reasons, such as the bio being full or target block device + * limitations. The target block device must allow bio's up to PAGE_SIZE, + * so it is always possible to add a single page to an empty bio. + * + * This should only be used by passthrough bios. + */ +int bio_add_pc_page(struct request_queue *q, struct bio *bio, + struct page *page, unsigned int len, unsigned int offset) +{ + bool same_page = false; + return bio_add_hw_page(q, bio, page, len, offset, + queue_max_hw_sectors(q), &same_page); +} +EXPORT_SYMBOL(bio_add_pc_page); + +/** + * bio_add_zone_append_page - attempt to add page to zone-append bio + * @bio: destination bio + * @page: page to add + * @len: vec entry length + * @offset: vec entry offset + * + * Attempt to add a page to the bio_vec maplist of a bio that will be submitted + * for a zone-append request. This can fail for a number of reasons, such as the + * bio being full or the target block device is not a zoned block device or + * other limitations of the target block device. The target block device must + * allow bio's up to PAGE_SIZE, so it is always possible to add a single page + * to an empty bio. + * + * Returns: number of bytes added to the bio, or 0 in case of a failure. + */ +int bio_add_zone_append_page(struct bio *bio, struct page *page, + unsigned int len, unsigned int offset) +{ + struct request_queue *q = bdev_get_queue(bio->bi_bdev); + bool same_page = false; + + if (WARN_ON_ONCE(bio_op(bio) != REQ_OP_ZONE_APPEND)) + return 0; + + if (WARN_ON_ONCE(!bdev_is_zoned(bio->bi_bdev))) + return 0; + + return bio_add_hw_page(q, bio, page, len, offset, + queue_max_zone_append_sectors(q), &same_page); +} +EXPORT_SYMBOL_GPL(bio_add_zone_append_page); + +/** + * __bio_add_page - add page(s) to a bio in a new segment + * @bio: destination bio + * @page: start page to add + * @len: length of the data to add, may cross pages + * @off: offset of the data relative to @page, may cross pages + * + * Add the data at @page + @off to @bio as a new bvec. The caller must ensure + * that @bio has space for another bvec. + */ +void __bio_add_page(struct bio *bio, struct page *page, + unsigned int len, unsigned int off) +{ + WARN_ON_ONCE(bio_flagged(bio, BIO_CLONED)); + WARN_ON_ONCE(bio_full(bio, len)); + + bvec_set_page(&bio->bi_io_vec[bio->bi_vcnt], page, len, off); + bio->bi_iter.bi_size += len; + bio->bi_vcnt++; +} +EXPORT_SYMBOL_GPL(__bio_add_page); + +/** + * bio_add_page - attempt to add page(s) to bio + * @bio: destination bio + * @page: start page to add + * @len: vec entry length, may cross pages + * @offset: vec entry offset relative to @page, may cross pages + * + * Attempt to add page(s) to the bio_vec maplist. This will only fail + * if either bio->bi_vcnt == bio->bi_max_vecs or it's a cloned bio. + */ +int bio_add_page(struct bio *bio, struct page *page, + unsigned int len, unsigned int offset) +{ + bool same_page = false; + + if (WARN_ON_ONCE(bio_flagged(bio, BIO_CLONED))) + return 0; + if (bio->bi_iter.bi_size > UINT_MAX - len) + return 0; + + if (bio->bi_vcnt > 0 && + bvec_try_merge_page(&bio->bi_io_vec[bio->bi_vcnt - 1], + page, len, offset, &same_page)) { + bio->bi_iter.bi_size += len; + return len; + } + + if (bio->bi_vcnt >= bio->bi_max_vecs) + return 0; + __bio_add_page(bio, page, len, offset); + return len; +} +EXPORT_SYMBOL(bio_add_page); + +void bio_add_folio_nofail(struct bio *bio, struct folio *folio, size_t len, + size_t off) +{ + WARN_ON_ONCE(len > UINT_MAX); + WARN_ON_ONCE(off > UINT_MAX); + __bio_add_page(bio, &folio->page, len, off); +} + +/** + * bio_add_folio - Attempt to add part of a folio to a bio. + * @bio: BIO to add to. + * @folio: Folio to add. + * @len: How many bytes from the folio to add. + * @off: First byte in this folio to add. + * + * Filesystems that use folios can call this function instead of calling + * bio_add_page() for each page in the folio. If @off is bigger than + * PAGE_SIZE, this function can create a bio_vec that starts in a page + * after the bv_page. BIOs do not support folios that are 4GiB or larger. + * + * Return: Whether the addition was successful. + */ +bool bio_add_folio(struct bio *bio, struct folio *folio, size_t len, + size_t off) +{ + if (len > UINT_MAX || off > UINT_MAX) + return false; + return bio_add_page(bio, &folio->page, len, off) > 0; +} +EXPORT_SYMBOL(bio_add_folio); + +void __bio_release_pages(struct bio *bio, bool mark_dirty) +{ + struct folio_iter fi; + + bio_for_each_folio_all(fi, bio) { + struct page *page; + size_t done = 0; + + if (mark_dirty) { + folio_lock(fi.folio); + folio_mark_dirty(fi.folio); + folio_unlock(fi.folio); + } + page = folio_page(fi.folio, fi.offset / PAGE_SIZE); + do { + bio_release_page(bio, page++); + done += PAGE_SIZE; + } while (done < fi.length); + } +} +EXPORT_SYMBOL_GPL(__bio_release_pages); + +void bio_iov_bvec_set(struct bio *bio, struct iov_iter *iter) +{ + size_t size = iov_iter_count(iter); + + WARN_ON_ONCE(bio->bi_max_vecs); + + if (bio_op(bio) == REQ_OP_ZONE_APPEND) { + struct request_queue *q = bdev_get_queue(bio->bi_bdev); + size_t max_sectors = queue_max_zone_append_sectors(q); + + size = min(size, max_sectors << SECTOR_SHIFT); + } + + bio->bi_vcnt = iter->nr_segs; + bio->bi_io_vec = (struct bio_vec *)iter->bvec; + bio->bi_iter.bi_bvec_done = iter->iov_offset; + bio->bi_iter.bi_size = size; + bio_set_flag(bio, BIO_CLONED); +} + +static int bio_iov_add_page(struct bio *bio, struct page *page, + unsigned int len, unsigned int offset) +{ + bool same_page = false; + + if (WARN_ON_ONCE(bio->bi_iter.bi_size > UINT_MAX - len)) + return -EIO; + + if (bio->bi_vcnt > 0 && + bvec_try_merge_page(&bio->bi_io_vec[bio->bi_vcnt - 1], + page, len, offset, &same_page)) { + bio->bi_iter.bi_size += len; + if (same_page) + bio_release_page(bio, page); + return 0; + } + __bio_add_page(bio, page, len, offset); + return 0; +} + +static int bio_iov_add_zone_append_page(struct bio *bio, struct page *page, + unsigned int len, unsigned int offset) +{ + struct request_queue *q = bdev_get_queue(bio->bi_bdev); + bool same_page = false; + + if (bio_add_hw_page(q, bio, page, len, offset, + queue_max_zone_append_sectors(q), &same_page) != len) + return -EINVAL; + if (same_page) + bio_release_page(bio, page); + return 0; +} + +#define PAGE_PTRS_PER_BVEC (sizeof(struct bio_vec) / sizeof(struct page *)) + +/** + * __bio_iov_iter_get_pages - pin user or kernel pages and add them to a bio + * @bio: bio to add pages to + * @iter: iov iterator describing the region to be mapped + * + * Extracts pages from *iter and appends them to @bio's bvec array. The pages + * will have to be cleaned up in the way indicated by the BIO_PAGE_PINNED flag. + * For a multi-segment *iter, this function only adds pages from the next + * non-empty segment of the iov iterator. + */ +static int __bio_iov_iter_get_pages(struct bio *bio, struct iov_iter *iter) +{ + iov_iter_extraction_t extraction_flags = 0; + unsigned short nr_pages = bio->bi_max_vecs - bio->bi_vcnt; + unsigned short entries_left = bio->bi_max_vecs - bio->bi_vcnt; + struct bio_vec *bv = bio->bi_io_vec + bio->bi_vcnt; + struct page **pages = (struct page **)bv; + ssize_t size, left; + unsigned len, i = 0; + size_t offset; + int ret = 0; + + /* + * Move page array up in the allocated memory for the bio vecs as far as + * possible so that we can start filling biovecs from the beginning + * without overwriting the temporary page array. + */ + BUILD_BUG_ON(PAGE_PTRS_PER_BVEC < 2); + pages += entries_left * (PAGE_PTRS_PER_BVEC - 1); + + if (bio->bi_bdev && blk_queue_pci_p2pdma(bio->bi_bdev->bd_disk->queue)) + extraction_flags |= ITER_ALLOW_P2PDMA; + + /* + * Each segment in the iov is required to be a block size multiple. + * However, we may not be able to get the entire segment if it spans + * more pages than bi_max_vecs allows, so we have to ALIGN_DOWN the + * result to ensure the bio's total size is correct. The remainder of + * the iov data will be picked up in the next bio iteration. + */ + size = iov_iter_extract_pages(iter, &pages, + UINT_MAX - bio->bi_iter.bi_size, + nr_pages, extraction_flags, &offset); + if (unlikely(size <= 0)) + return size ? size : -EFAULT; + + nr_pages = DIV_ROUND_UP(offset + size, PAGE_SIZE); + + if (bio->bi_bdev) { + size_t trim = size & (bdev_logical_block_size(bio->bi_bdev) - 1); + iov_iter_revert(iter, trim); + size -= trim; + } + + if (unlikely(!size)) { + ret = -EFAULT; + goto out; + } + + for (left = size, i = 0; left > 0; left -= len, i++) { + struct page *page = pages[i]; + + len = min_t(size_t, PAGE_SIZE - offset, left); + if (bio_op(bio) == REQ_OP_ZONE_APPEND) { + ret = bio_iov_add_zone_append_page(bio, page, len, + offset); + if (ret) + break; + } else + bio_iov_add_page(bio, page, len, offset); + + offset = 0; + } + + iov_iter_revert(iter, left); +out: + while (i < nr_pages) + bio_release_page(bio, pages[i++]); + + return ret; +} + +/** + * bio_iov_iter_get_pages - add user or kernel pages to a bio + * @bio: bio to add pages to + * @iter: iov iterator describing the region to be added + * + * This takes either an iterator pointing to user memory, or one pointing to + * kernel pages (BVEC iterator). If we're adding user pages, we pin them and + * map them into the kernel. On IO completion, the caller should put those + * pages. For bvec based iterators bio_iov_iter_get_pages() uses the provided + * bvecs rather than copying them. Hence anyone issuing kiocb based IO needs + * to ensure the bvecs and pages stay referenced until the submitted I/O is + * completed by a call to ->ki_complete() or returns with an error other than + * -EIOCBQUEUED. The caller needs to check if the bio is flagged BIO_NO_PAGE_REF + * on IO completion. If it isn't, then pages should be released. + * + * The function tries, but does not guarantee, to pin as many pages as + * fit into the bio, or are requested in @iter, whatever is smaller. If + * MM encounters an error pinning the requested pages, it stops. Error + * is returned only if 0 pages could be pinned. + */ +int bio_iov_iter_get_pages(struct bio *bio, struct iov_iter *iter) +{ + int ret = 0; + + if (WARN_ON_ONCE(bio_flagged(bio, BIO_CLONED))) + return -EIO; + + if (iov_iter_is_bvec(iter)) { + bio_iov_bvec_set(bio, iter); + iov_iter_advance(iter, bio->bi_iter.bi_size); + return 0; + } + + if (iov_iter_extract_will_pin(iter)) + bio_set_flag(bio, BIO_PAGE_PINNED); + do { + ret = __bio_iov_iter_get_pages(bio, iter); + } while (!ret && iov_iter_count(iter) && !bio_full(bio, 0)); + + return bio->bi_vcnt ? 0 : ret; +} +EXPORT_SYMBOL_GPL(bio_iov_iter_get_pages); + +static void submit_bio_wait_endio(struct bio *bio) +{ + complete(bio->bi_private); +} + +/** + * submit_bio_wait - submit a bio, and wait until it completes + * @bio: The &struct bio which describes the I/O + * + * Simple wrapper around submit_bio(). Returns 0 on success, or the error from + * bio_endio() on failure. + * + * WARNING: Unlike to how submit_bio() is usually used, this function does not + * result in bio reference to be consumed. The caller must drop the reference + * on his own. + */ +int submit_bio_wait(struct bio *bio) +{ + DECLARE_COMPLETION_ONSTACK_MAP(done, + bio->bi_bdev->bd_disk->lockdep_map); + unsigned long hang_check; + + bio->bi_private = &done; + bio->bi_end_io = submit_bio_wait_endio; + bio->bi_opf |= REQ_SYNC; + submit_bio(bio); + + /* Prevent hang_check timer from firing at us during very long I/O */ + hang_check = sysctl_hung_task_timeout_secs; + if (hang_check) + while (!wait_for_completion_io_timeout(&done, + hang_check * (HZ/2))) + ; + else + wait_for_completion_io(&done); + + return blk_status_to_errno(bio->bi_status); +} +EXPORT_SYMBOL(submit_bio_wait); + +void __bio_advance(struct bio *bio, unsigned bytes) +{ + if (bio_integrity(bio)) + bio_integrity_advance(bio, bytes); + + bio_crypt_advance(bio, bytes); + bio_advance_iter(bio, &bio->bi_iter, bytes); +} +EXPORT_SYMBOL(__bio_advance); + +void bio_copy_data_iter(struct bio *dst, struct bvec_iter *dst_iter, + struct bio *src, struct bvec_iter *src_iter) +{ + while (src_iter->bi_size && dst_iter->bi_size) { + struct bio_vec src_bv = bio_iter_iovec(src, *src_iter); + struct bio_vec dst_bv = bio_iter_iovec(dst, *dst_iter); + unsigned int bytes = min(src_bv.bv_len, dst_bv.bv_len); + void *src_buf = bvec_kmap_local(&src_bv); + void *dst_buf = bvec_kmap_local(&dst_bv); + + memcpy(dst_buf, src_buf, bytes); + + kunmap_local(dst_buf); + kunmap_local(src_buf); + + bio_advance_iter_single(src, src_iter, bytes); + bio_advance_iter_single(dst, dst_iter, bytes); + } +} +EXPORT_SYMBOL(bio_copy_data_iter); + +/** + * bio_copy_data - copy contents of data buffers from one bio to another + * @src: source bio + * @dst: destination bio + * + * Stops when it reaches the end of either @src or @dst - that is, copies + * min(src->bi_size, dst->bi_size) bytes (or the equivalent for lists of bios). + */ +void bio_copy_data(struct bio *dst, struct bio *src) +{ + struct bvec_iter src_iter = src->bi_iter; + struct bvec_iter dst_iter = dst->bi_iter; + + bio_copy_data_iter(dst, &dst_iter, src, &src_iter); +} +EXPORT_SYMBOL(bio_copy_data); + +void bio_free_pages(struct bio *bio) +{ + struct bio_vec *bvec; + struct bvec_iter_all iter_all; + + bio_for_each_segment_all(bvec, bio, iter_all) + __free_page(bvec->bv_page); +} +EXPORT_SYMBOL(bio_free_pages); + +/* + * bio_set_pages_dirty() and bio_check_pages_dirty() are support functions + * for performing direct-IO in BIOs. + * + * The problem is that we cannot run folio_mark_dirty() from interrupt context + * because the required locks are not interrupt-safe. So what we can do is to + * mark the pages dirty _before_ performing IO. And in interrupt context, + * check that the pages are still dirty. If so, fine. If not, redirty them + * in process context. + * + * Note that this code is very hard to test under normal circumstances because + * direct-io pins the pages with get_user_pages(). This makes + * is_page_cache_freeable return false, and the VM will not clean the pages. + * But other code (eg, flusher threads) could clean the pages if they are mapped + * pagecache. + * + * Simply disabling the call to bio_set_pages_dirty() is a good way to test the + * deferred bio dirtying paths. + */ + +/* + * bio_set_pages_dirty() will mark all the bio's pages as dirty. + */ +void bio_set_pages_dirty(struct bio *bio) +{ + struct folio_iter fi; + + bio_for_each_folio_all(fi, bio) { + folio_lock(fi.folio); + folio_mark_dirty(fi.folio); + folio_unlock(fi.folio); + } +} +EXPORT_SYMBOL_GPL(bio_set_pages_dirty); + +/* + * bio_check_pages_dirty() will check that all the BIO's pages are still dirty. + * If they are, then fine. If, however, some pages are clean then they must + * have been written out during the direct-IO read. So we take another ref on + * the BIO and re-dirty the pages in process context. + * + * It is expected that bio_check_pages_dirty() will wholly own the BIO from + * here on. It will unpin each page and will run one bio_put() against the + * BIO. + */ + +static void bio_dirty_fn(struct work_struct *work); + +static DECLARE_WORK(bio_dirty_work, bio_dirty_fn); +static DEFINE_SPINLOCK(bio_dirty_lock); +static struct bio *bio_dirty_list; + +/* + * This runs in process context + */ +static void bio_dirty_fn(struct work_struct *work) +{ + struct bio *bio, *next; + + spin_lock_irq(&bio_dirty_lock); + next = bio_dirty_list; + bio_dirty_list = NULL; + spin_unlock_irq(&bio_dirty_lock); + + while ((bio = next) != NULL) { + next = bio->bi_private; + + bio_release_pages(bio, true); + bio_put(bio); + } +} + +void bio_check_pages_dirty(struct bio *bio) +{ + struct folio_iter fi; + unsigned long flags; + + bio_for_each_folio_all(fi, bio) { + if (!folio_test_dirty(fi.folio)) + goto defer; + } + + bio_release_pages(bio, false); + bio_put(bio); + return; +defer: + spin_lock_irqsave(&bio_dirty_lock, flags); + bio->bi_private = bio_dirty_list; + bio_dirty_list = bio; + spin_unlock_irqrestore(&bio_dirty_lock, flags); + schedule_work(&bio_dirty_work); +} +EXPORT_SYMBOL_GPL(bio_check_pages_dirty); + +static inline bool bio_remaining_done(struct bio *bio) +{ + /* + * If we're not chaining, then ->__bi_remaining is always 1 and + * we always end io on the first invocation. + */ + if (!bio_flagged(bio, BIO_CHAIN)) + return true; + + BUG_ON(atomic_read(&bio->__bi_remaining) <= 0); + + if (atomic_dec_and_test(&bio->__bi_remaining)) { + bio_clear_flag(bio, BIO_CHAIN); + return true; + } + + return false; +} + +/** + * bio_endio - end I/O on a bio + * @bio: bio + * + * Description: + * bio_endio() will end I/O on the whole bio. bio_endio() is the preferred + * way to end I/O on a bio. No one should call bi_end_io() directly on a + * bio unless they own it and thus know that it has an end_io function. + * + * bio_endio() can be called several times on a bio that has been chained + * using bio_chain(). The ->bi_end_io() function will only be called the + * last time. + **/ +void bio_endio(struct bio *bio) +{ +again: + if (!bio_remaining_done(bio)) + return; + if (!bio_integrity_endio(bio)) + return; + + rq_qos_done_bio(bio); + + if (bio->bi_bdev && bio_flagged(bio, BIO_TRACE_COMPLETION)) { + trace_block_bio_complete(bdev_get_queue(bio->bi_bdev), bio); + bio_clear_flag(bio, BIO_TRACE_COMPLETION); + } + + /* + * Need to have a real endio function for chained bios, otherwise + * various corner cases will break (like stacking block devices that + * save/restore bi_end_io) - however, we want to avoid unbounded + * recursion and blowing the stack. Tail call optimization would + * handle this, but compiling with frame pointers also disables + * gcc's sibling call optimization. + */ + if (bio->bi_end_io == bio_chain_endio) { + bio = __bio_chain_endio(bio); + goto again; + } + + blk_throtl_bio_endio(bio); + /* release cgroup info */ + bio_uninit(bio); + if (bio->bi_end_io) + bio->bi_end_io(bio); +} +EXPORT_SYMBOL(bio_endio); + +/** + * bio_split - split a bio + * @bio: bio to split + * @sectors: number of sectors to split from the front of @bio + * @gfp: gfp mask + * @bs: bio set to allocate from + * + * Allocates and returns a new bio which represents @sectors from the start of + * @bio, and updates @bio to represent the remaining sectors. + * + * Unless this is a discard request the newly allocated bio will point + * to @bio's bi_io_vec. It is the caller's responsibility to ensure that + * neither @bio nor @bs are freed before the split bio. + */ +struct bio *bio_split(struct bio *bio, int sectors, + gfp_t gfp, struct bio_set *bs) +{ + struct bio *split; + + BUG_ON(sectors <= 0); + BUG_ON(sectors >= bio_sectors(bio)); + + /* Zone append commands cannot be split */ + if (WARN_ON_ONCE(bio_op(bio) == REQ_OP_ZONE_APPEND)) + return NULL; + + split = bio_alloc_clone(bio->bi_bdev, bio, gfp, bs); + if (!split) + return NULL; + + split->bi_iter.bi_size = sectors << 9; + + if (bio_integrity(split)) + bio_integrity_trim(split); + + bio_advance(bio, split->bi_iter.bi_size); + + if (bio_flagged(bio, BIO_TRACE_COMPLETION)) + bio_set_flag(split, BIO_TRACE_COMPLETION); + + return split; +} +EXPORT_SYMBOL(bio_split); + +/** + * bio_trim - trim a bio + * @bio: bio to trim + * @offset: number of sectors to trim from the front of @bio + * @size: size we want to trim @bio to, in sectors + * + * This function is typically used for bios that are cloned and submitted + * to the underlying device in parts. + */ +void bio_trim(struct bio *bio, sector_t offset, sector_t size) +{ + if (WARN_ON_ONCE(offset > BIO_MAX_SECTORS || size > BIO_MAX_SECTORS || + offset + size > bio_sectors(bio))) + return; + + size <<= 9; + if (offset == 0 && size == bio->bi_iter.bi_size) + return; + + bio_advance(bio, offset << 9); + bio->bi_iter.bi_size = size; + + if (bio_integrity(bio)) + bio_integrity_trim(bio); +} +EXPORT_SYMBOL_GPL(bio_trim); + +/* + * create memory pools for biovec's in a bio_set. + * use the global biovec slabs created for general use. + */ +int biovec_init_pool(mempool_t *pool, int pool_entries) +{ + struct biovec_slab *bp = bvec_slabs + ARRAY_SIZE(bvec_slabs) - 1; + + return mempool_init_slab_pool(pool, pool_entries, bp->slab); +} + +/* + * bioset_exit - exit a bioset initialized with bioset_init() + * + * May be called on a zeroed but uninitialized bioset (i.e. allocated with + * kzalloc()). + */ +void bioset_exit(struct bio_set *bs) +{ + bio_alloc_cache_destroy(bs); + if (bs->rescue_workqueue) + destroy_workqueue(bs->rescue_workqueue); + bs->rescue_workqueue = NULL; + + mempool_exit(&bs->bio_pool); + mempool_exit(&bs->bvec_pool); + + bioset_integrity_free(bs); + if (bs->bio_slab) + bio_put_slab(bs); + bs->bio_slab = NULL; +} +EXPORT_SYMBOL(bioset_exit); + +/** + * bioset_init - Initialize a bio_set + * @bs: pool to initialize + * @pool_size: Number of bio and bio_vecs to cache in the mempool + * @front_pad: Number of bytes to allocate in front of the returned bio + * @flags: Flags to modify behavior, currently %BIOSET_NEED_BVECS + * and %BIOSET_NEED_RESCUER + * + * Description: + * Set up a bio_set to be used with @bio_alloc_bioset. Allows the caller + * to ask for a number of bytes to be allocated in front of the bio. + * Front pad allocation is useful for embedding the bio inside + * another structure, to avoid allocating extra data to go with the bio. + * Note that the bio must be embedded at the END of that structure always, + * or things will break badly. + * If %BIOSET_NEED_BVECS is set in @flags, a separate pool will be allocated + * for allocating iovecs. This pool is not needed e.g. for bio_init_clone(). + * If %BIOSET_NEED_RESCUER is set, a workqueue is created which can be used + * to dispatch queued requests when the mempool runs out of space. + * + */ +int bioset_init(struct bio_set *bs, + unsigned int pool_size, + unsigned int front_pad, + int flags) +{ + bs->front_pad = front_pad; + if (flags & BIOSET_NEED_BVECS) + bs->back_pad = BIO_INLINE_VECS * sizeof(struct bio_vec); + else + bs->back_pad = 0; + + spin_lock_init(&bs->rescue_lock); + bio_list_init(&bs->rescue_list); + INIT_WORK(&bs->rescue_work, bio_alloc_rescue); + + bs->bio_slab = bio_find_or_create_slab(bs); + if (!bs->bio_slab) + return -ENOMEM; + + if (mempool_init_slab_pool(&bs->bio_pool, pool_size, bs->bio_slab)) + goto bad; + + if ((flags & BIOSET_NEED_BVECS) && + biovec_init_pool(&bs->bvec_pool, pool_size)) + goto bad; + + if (flags & BIOSET_NEED_RESCUER) { + bs->rescue_workqueue = alloc_workqueue("bioset", + WQ_MEM_RECLAIM, 0); + if (!bs->rescue_workqueue) + goto bad; + } + if (flags & BIOSET_PERCPU_CACHE) { + bs->cache = alloc_percpu(struct bio_alloc_cache); + if (!bs->cache) + goto bad; + cpuhp_state_add_instance_nocalls(CPUHP_BIO_DEAD, &bs->cpuhp_dead); + } + + return 0; +bad: + bioset_exit(bs); + return -ENOMEM; +} +EXPORT_SYMBOL(bioset_init); + +static int __init init_bio(void) +{ + int i; + + BUILD_BUG_ON(BIO_FLAG_LAST > 8 * sizeof_field(struct bio, bi_flags)); + + bio_integrity_init(); + + for (i = 0; i < ARRAY_SIZE(bvec_slabs); i++) { + struct biovec_slab *bvs = bvec_slabs + i; + + bvs->slab = kmem_cache_create(bvs->name, + bvs->nr_vecs * sizeof(struct bio_vec), 0, + SLAB_HWCACHE_ALIGN | SLAB_PANIC, NULL); + } + + cpuhp_setup_state_multi(CPUHP_BIO_DEAD, "block/bio:dead", NULL, + bio_cpu_dead); + + if (bioset_init(&fs_bio_set, BIO_POOL_SIZE, 0, + BIOSET_NEED_BVECS | BIOSET_PERCPU_CACHE)) + panic("bio: can't allocate bios\n"); + + if (bioset_integrity_create(&fs_bio_set, BIO_POOL_SIZE)) + panic("bio: can't create integrity pool\n"); + + return 0; +} +subsys_initcall(init_bio); |