| // 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" |
| |
| struct bio_alloc_cache { |
| struct bio *free_list; |
| unsigned int nr; |
| }; |
| |
| 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 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) { |
| 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. |
| * |
| * If REQ_ALLOC_CACHE is set, the final put of the bio MUST be done from process |
| * context, not hard/soft IRQ. |
| * |
| * 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; |
| |
| 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(struct bio *bio) |
| { |
| struct bio_vec bv; |
| struct bvec_iter iter; |
| |
| bio_for_each_segment(bv, bio, iter) |
| memzero_bvec(&bv); |
| } |
| EXPORT_SYMBOL(zero_fill_bio); |
| |
| /** |
| * 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); |
| } |
| |
| #define ALLOC_CACHE_MAX 512 |
| #define ALLOC_CACHE_SLACK 64 |
| |
| static void 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; |
| } |
| } |
| |
| 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; |
| } |
| |
| /** |
| * 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) && !WARN_ON_ONCE(in_interrupt())) { |
| struct bio_alloc_cache *cache; |
| |
| bio_uninit(bio); |
| cache = per_cpu_ptr(bio->bi_pool->cache, get_cpu()); |
| bio->bi_next = cache->free_list; |
| bio->bi_bdev = NULL; |
| cache->free_list = bio; |
| if (++cache->nr > ALLOC_CACHE_MAX + ALLOC_CACHE_SLACK) |
| bio_alloc_cache_prune(cache, ALLOC_CACHE_SLACK); |
| put_cpu(); |
| } 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 inline bool page_is_mergeable(const 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; |
| |
| *same_page = ((vec_end_addr & PAGE_MASK) == page_addr); |
| if (*same_page) |
| return true; |
| else if (IS_ENABLED(CONFIG_KMSAN)) |
| return false; |
| return (bv->bv_page + bv_end / PAGE_SIZE) == (page + off / PAGE_SIZE); |
| } |
| |
| /** |
| * __bio_try_merge_page - try appending data to an existing bvec. |
| * @bio: destination bio |
| * @page: start page to add |
| * @len: length of the data to add |
| * @off: offset of the data relative to @page |
| * @same_page: return if the segment has been merged inside the same page |
| * |
| * Try to add the data at @page + @off to the last bvec of @bio. This is a |
| * useful optimisation for file systems with a block size smaller than the |
| * page size. |
| * |
| * Warn if (@len, @off) crosses pages in case that @same_page is true. |
| * |
| * Return %true on success or %false on failure. |
| */ |
| static bool __bio_try_merge_page(struct bio *bio, struct page *page, |
| unsigned int len, unsigned int off, bool *same_page) |
| { |
| if (WARN_ON_ONCE(bio_flagged(bio, BIO_CLONED))) |
| return false; |
| |
| if (bio->bi_vcnt > 0) { |
| struct bio_vec *bv = &bio->bi_io_vec[bio->bi_vcnt - 1]; |
| |
| if (page_is_mergeable(bv, page, len, off, same_page)) { |
| if (bio->bi_iter.bi_size > UINT_MAX - len) { |
| *same_page = false; |
| return false; |
| } |
| bv->bv_len += len; |
| bio->bi_iter.bi_size += len; |
| return true; |
| } |
| } |
| return false; |
| } |
| |
| /* |
| * 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. |
| */ |
| static bool bio_try_merge_hw_seg(struct request_queue *q, struct bio *bio, |
| struct page *page, unsigned len, |
| unsigned offset, bool *same_page) |
| { |
| struct bio_vec *bv = &bio->bi_io_vec[bio->bi_vcnt - 1]; |
| 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 __bio_try_merge_page(bio, 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) |
| { |
| struct bio_vec *bvec; |
| |
| if (WARN_ON_ONCE(bio_flagged(bio, BIO_CLONED))) |
| return 0; |
| |
| if (((bio->bi_iter.bi_size + len) >> 9) > max_sectors) |
| return 0; |
| |
| if (bio->bi_vcnt > 0) { |
| if (bio_try_merge_hw_seg(q, bio, page, len, offset, same_page)) |
| return len; |
| |
| /* |
| * If the queue doesn't support SG gaps and adding this segment |
| * would create a gap, disallow it. |
| */ |
| bvec = &bio->bi_io_vec[bio->bi_vcnt - 1]; |
| if (bvec_gap_to_prev(&q->limits, bvec, offset)) |
| return 0; |
| } |
| |
| if (bio_full(bio, len)) |
| return 0; |
| |
| if (bio->bi_vcnt >= queue_max_segments(q)) |
| 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 (!__bio_try_merge_page(bio, page, len, offset, &same_page)) { |
| if (bio_full(bio, len)) |
| return 0; |
| __bio_add_page(bio, page, len, offset); |
| } |
| return len; |
| } |
| EXPORT_SYMBOL(bio_add_page); |
| |
| /** |
| * 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; |
| } |
| |
| void __bio_release_pages(struct bio *bio, bool mark_dirty) |
| { |
| struct bvec_iter_all iter_all; |
| struct bio_vec *bvec; |
| |
| bio_for_each_segment_all(bvec, bio, iter_all) { |
| if (mark_dirty && !PageCompound(bvec->bv_page)) |
| set_page_dirty_lock(bvec->bv_page); |
| put_page(bvec->bv_page); |
| } |
| } |
| 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_NO_PAGE_REF); |
| 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 (!__bio_try_merge_page(bio, page, len, offset, &same_page)) { |
| __bio_add_page(bio, page, len, offset); |
| return 0; |
| } |
| |
| if (same_page) |
| put_page(page); |
| 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) |
| put_page(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 |
| * |
| * Pins pages from *iter and appends them to @bio's bvec array. The |
| * pages will have to be released using put_page() when done. |
| * For 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) |
| { |
| 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, trim; |
| 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); |
| |
| /* |
| * 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_get_pages2(iter, pages, UINT_MAX - bio->bi_iter.bi_size, |
| nr_pages, &offset); |
| if (unlikely(size <= 0)) |
| return size ? size : -EFAULT; |
| |
| nr_pages = DIV_ROUND_UP(offset + size, PAGE_SIZE); |
| |
| 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) |
| put_page(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 (iov_iter_is_bvec(iter)) { |
| bio_iov_bvec_set(bio, iter); |
| iov_iter_advance(iter, bio->bi_iter.bi_size); |
| return 0; |
| } |
| |
| 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 set_page_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. |
| * |
| * We special-case compound pages here: normally this means reads into hugetlb |
| * pages. The logic in here doesn't really work right for compound pages |
| * because the VM does not uniformly chase down the head page in all cases. |
| * But dirtiness of compound pages is pretty meaningless anyway: the VM doesn't |
| * handle them at all. So we skip compound pages here at an early stage. |
| * |
| * 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 bio_vec *bvec; |
| struct bvec_iter_all iter_all; |
| |
| bio_for_each_segment_all(bvec, bio, iter_all) { |
| if (!PageCompound(bvec->bv_page)) |
| set_page_dirty_lock(bvec->bv_page); |
| } |
| } |
| |
| /* |
| * 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 run one put_page() against 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 bio_vec *bvec; |
| unsigned long flags; |
| struct bvec_iter_all iter_all; |
| |
| bio_for_each_segment_all(bvec, bio, iter_all) { |
| if (!PageDirty(bvec->bv_page) && !PageCompound(bvec->bv_page)) |
| 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); |
| } |
| |
| 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; |
| |
| 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); |