// SPDX-License-Identifier: GPL-2.0 /* * Copyright (C) 2001 Jens Axboe */ #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include "blk.h" #include "blk-rq-qos.h" 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, 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) { BIO_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_uninit(bio); if (bs) { bvec_free(&bs->bvec_pool, bio->bi_io_vec, bio->bi_max_vecs); /* * If we have front padding, adjust the bio pointer before freeing */ p = bio; p -= bs->front_pad; mempool_free(p, &bs->bio_pool); } else { /* Bio was allocated by bio_kmalloc() */ kfree(bio); } } /* * 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 bio_vec *table, unsigned short max_vecs) { memset(bio, 0, sizeof(*bio)); atomic_set(&bio->__bi_remaining, 1); atomic_set(&bio->__bi_cnt, 1); bio->bi_io_vec = table; bio->bi_max_vecs = max_vecs; } EXPORT_SYMBOL(bio_init); /** * bio_reset - reinitialize a bio * @bio: bio to reset * * 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) { bio_uninit(bio); memset(bio, 0, BIO_RESET_BYTES); atomic_set(&bio->__bi_remaining, 1); } 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); 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); } /** * bio_alloc_bioset - allocate a bio for I/O * @gfp_mask: the GFP_* mask given to the slab allocator * @nr_iovecs: number of iovecs to pre-allocate * @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(gfp_t gfp_mask, unsigned short nr_iovecs, struct bio_set *bs) { gfp_t saved_gfp = gfp_mask; struct bio *bio; void *p; /* should not use nobvec bioset for nr_iovecs > 0 */ if (WARN_ON_ONCE(!mempool_initialized(&bs->bvec_pool) && nr_iovecs > 0)) return NULL; /* * 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_iovecs > BIO_INLINE_VECS) { struct bio_vec *bvl = NULL; bvl = bvec_alloc(&bs->bvec_pool, &nr_iovecs, gfp_mask); if (!bvl && gfp_mask != saved_gfp) { punt_bios_to_rescuer(bs); gfp_mask = saved_gfp; bvl = bvec_alloc(&bs->bvec_pool, &nr_iovecs, gfp_mask); } if (unlikely(!bvl)) goto err_free; bio_init(bio, bvl, nr_iovecs); } else if (nr_iovecs) { bio_init(bio, bio->bi_inline_vecs, BIO_INLINE_VECS); } else { bio_init(bio, NULL, 0); } 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 for I/O * @gfp_mask: the GFP_* mask given to the slab allocator * @nr_iovecs: number of iovecs to pre-allocate * * Use kmalloc to allocate and initialize a bio. * * Returns: Pointer to new bio on success, NULL on failure. */ struct bio *bio_kmalloc(gfp_t gfp_mask, unsigned short nr_iovecs) { struct bio *bio; if (nr_iovecs > UIO_MAXIOV) return NULL; bio = kmalloc(struct_size(bio, bi_inline_vecs, nr_iovecs), gfp_mask); if (unlikely(!bio)) return NULL; bio_init(bio, nr_iovecs ? bio->bi_inline_vecs : NULL, nr_iovecs); bio->bi_pool = NULL; return bio; } EXPORT_SYMBOL(bio_kmalloc); void zero_fill_bio(struct bio *bio) { unsigned long flags; struct bio_vec bv; struct bvec_iter iter; bio_for_each_segment(bv, bio, iter) { char *data = bvec_kmap_irq(&bv, &flags); memset(data, 0, bv.bv_len); flush_dcache_page(bv.bv_page); bvec_kunmap_irq(data, &flags); } } 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. */ 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, 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); } /** * 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 (!bio_flagged(bio, BIO_REFFED)) bio_free(bio); else { BIO_BUG_ON(!atomic_read(&bio->__bi_cnt)); /* * last put frees it */ if (atomic_dec_and_test(&bio->__bi_cnt)) bio_free(bio); } } EXPORT_SYMBOL(bio_put); /** * __bio_clone_fast - clone a bio that shares the original bio's biovec * @bio: destination bio * @bio_src: bio to clone * * Clone a &bio. Caller will own the returned bio, but not * the actual data it points to. Reference count of returned * bio will be one. * * Caller must ensure that @bio_src is not freed before @bio. */ void __bio_clone_fast(struct bio *bio, struct bio *bio_src) { WARN_ON_ONCE(bio->bi_pool && bio->bi_max_vecs); /* * most users will be overriding ->bi_bdev with a new target, * so we don't set nor calculate new physical/hw segment counts here */ bio->bi_bdev = bio_src->bi_bdev; bio_set_flag(bio, BIO_CLONED); if (bio_flagged(bio_src, BIO_THROTTLED)) bio_set_flag(bio, BIO_THROTTLED); if (bio_flagged(bio_src, BIO_REMAPPED)) bio_set_flag(bio, BIO_REMAPPED); bio->bi_opf = bio_src->bi_opf; bio->bi_ioprio = bio_src->bi_ioprio; bio->bi_write_hint = bio_src->bi_write_hint; bio->bi_iter = bio_src->bi_iter; bio->bi_io_vec = bio_src->bi_io_vec; bio_clone_blkg_association(bio, bio_src); blkcg_bio_issue_init(bio); } EXPORT_SYMBOL(__bio_clone_fast); /** * bio_clone_fast - clone a bio that shares the original bio's biovec * @bio: bio to clone * @gfp_mask: allocation priority * @bs: bio_set to allocate from * * Like __bio_clone_fast, only also allocates the returned bio */ struct bio *bio_clone_fast(struct bio *bio, gfp_t gfp_mask, struct bio_set *bs) { struct bio *b; b = bio_alloc_bioset(gfp_mask, 0, bs); if (!b) return NULL; __bio_clone_fast(b, bio); if (bio_crypt_clone(b, bio, gfp_mask) < 0) goto err_put; if (bio_integrity(bio) && bio_integrity_clone(b, bio, gfp_mask) < 0) goto err_put; return b; err_put: bio_put(b); return NULL; } EXPORT_SYMBOL(bio_clone_fast); const char *bio_devname(struct bio *bio, char *buf) { return bdevname(bio->bi_bdev, buf); } EXPORT_SYMBOL(bio_devname); 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; return (bv->bv_page + bv_end / PAGE_SIZE) == (page + off / PAGE_SIZE); } /* * 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, bvec, offset)) return 0; } if (bio_full(bio, len)) return 0; if (bio->bi_vcnt >= queue_max_segments(q)) return 0; bvec = &bio->bi_io_vec[bio->bi_vcnt]; bvec->bv_page = page; bvec->bv_len = len; bvec->bv_offset = 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 = bio->bi_bdev->bd_disk->queue; bool same_page = false; if (WARN_ON_ONCE(bio_op(bio) != REQ_OP_ZONE_APPEND)) return 0; if (WARN_ON_ONCE(!blk_queue_is_zoned(q))) 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_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. */ 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; } EXPORT_SYMBOL_GPL(__bio_try_merge_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) { struct bio_vec *bv = &bio->bi_io_vec[bio->bi_vcnt]; WARN_ON_ONCE(bio_flagged(bio, BIO_CLONED)); WARN_ON_ONCE(bio_full(bio, len)); bv->bv_page = page; bv->bv_offset = off; bv->bv_len = len; bio->bi_iter.bi_size += len; bio->bi_vcnt++; if (!bio_flagged(bio, BIO_WORKINGSET) && unlikely(PageWorkingset(page))) bio_set_flag(bio, BIO_WORKINGSET); } 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); void bio_release_pages(struct bio *bio, bool mark_dirty) { struct bvec_iter_all iter_all; struct bio_vec *bvec; if (bio_flagged(bio, BIO_NO_PAGE_REF)) return; 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); static void __bio_iov_bvec_set(struct bio *bio, struct iov_iter *iter) { WARN_ON_ONCE(bio->bi_max_vecs); 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 = iter->count; bio_set_flag(bio, BIO_NO_PAGE_REF); bio_set_flag(bio, BIO_CLONED); } static int bio_iov_bvec_set(struct bio *bio, struct iov_iter *iter) { __bio_iov_bvec_set(bio, iter); iov_iter_advance(iter, iter->count); return 0; } static int bio_iov_bvec_set_append(struct bio *bio, struct iov_iter *iter) { struct request_queue *q = bio->bi_bdev->bd_disk->queue; struct iov_iter i = *iter; iov_iter_truncate(&i, queue_max_zone_append_sectors(q) << 9); __bio_iov_bvec_set(bio, &i); iov_iter_advance(iter, i.count); return 0; } static void bio_put_pages(struct page **pages, size_t size, size_t off) { size_t i, nr = DIV_ROUND_UP(size + (off & ~PAGE_MASK), PAGE_SIZE); for (i = 0; i < nr; i++) put_page(pages[i]); } #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; bool same_page = false; ssize_t size, left; unsigned len, i; size_t offset; /* * 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); size = iov_iter_get_pages(iter, pages, LONG_MAX, nr_pages, &offset); if (unlikely(size <= 0)) return size ? size : -EFAULT; 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_try_merge_page(bio, page, len, offset, &same_page)) { if (same_page) put_page(page); } else { if (WARN_ON_ONCE(bio_full(bio, len))) { bio_put_pages(pages + i, left, offset); return -EINVAL; } __bio_add_page(bio, page, len, offset); } offset = 0; } iov_iter_advance(iter, size); return 0; } static int __bio_iov_append_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 request_queue *q = bio->bi_bdev->bd_disk->queue; unsigned int max_append_sectors = queue_max_zone_append_sectors(q); struct bio_vec *bv = bio->bi_io_vec + bio->bi_vcnt; struct page **pages = (struct page **)bv; ssize_t size, left; unsigned len, i; size_t offset; int ret = 0; if (WARN_ON_ONCE(!max_append_sectors)) return 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); size = iov_iter_get_pages(iter, pages, LONG_MAX, nr_pages, &offset); if (unlikely(size <= 0)) return size ? size : -EFAULT; for (left = size, i = 0; left > 0; left -= len, i++) { struct page *page = pages[i]; bool same_page = false; len = min_t(size_t, PAGE_SIZE - offset, left); if (bio_add_hw_page(q, bio, page, len, offset, max_append_sectors, &same_page) != len) { bio_put_pages(pages + i, left, offset); ret = -EINVAL; break; } if (same_page) put_page(page); offset = 0; } iov_iter_advance(iter, size - left); 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. * * It's intended for direct IO, so doesn't do PSI tracking, the caller is * responsible for setting BIO_WORKINGSET if necessary. */ int bio_iov_iter_get_pages(struct bio *bio, struct iov_iter *iter) { int ret = 0; if (iov_iter_is_bvec(iter)) { if (bio_op(bio) == REQ_OP_ZONE_APPEND) return bio_iov_bvec_set_append(bio, iter); return bio_iov_bvec_set(bio, iter); } do { if (bio_op(bio) == REQ_OP_ZONE_APPEND) ret = __bio_iov_append_get_pages(bio, iter); else ret = __bio_iov_iter_get_pages(bio, iter); } while (!ret && iov_iter_count(iter) && !bio_full(bio, 0)); /* don't account direct I/O as memory stall */ bio_clear_flag(bio, BIO_WORKINGSET); 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); /** * bio_advance - increment/complete a bio by some number of bytes * @bio: bio to advance * @bytes: number of bytes to complete * * This updates bi_sector, bi_size and bi_idx; if the number of bytes to * complete doesn't align with a bvec boundary, then bv_len and bv_offset will * be updated on the last bvec as well. * * @bio will then represent the remaining, uncompleted portion of the io. */ 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) { struct bio_vec src_bv, dst_bv; void *src_p, *dst_p; unsigned bytes; while (src_iter->bi_size && dst_iter->bi_size) { src_bv = bio_iter_iovec(src, *src_iter); dst_bv = bio_iter_iovec(dst, *dst_iter); bytes = min(src_bv.bv_len, dst_bv.bv_len); src_p = kmap_atomic(src_bv.bv_page); dst_p = kmap_atomic(dst_bv.bv_page); memcpy(dst_p + dst_bv.bv_offset, src_p + src_bv.bv_offset, bytes); kunmap_atomic(dst_p); kunmap_atomic(src_p); flush_dcache_page(dst_bv.bv_page); 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; if (bio->bi_bdev) rq_qos_done_bio(bio->bi_bdev->bd_disk->queue, bio); if (bio->bi_bdev && bio_flagged(bio, BIO_TRACE_COMPLETION)) { trace_block_bio_complete(bio->bi_bdev->bd_disk->queue, 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_clone_fast(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 */ void bio_trim(struct bio *bio, int offset, int size) { /* 'bio' is a cloned bio which we need to trim to match * the given offset and size. */ 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) { 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_clone_fast(). * 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)) return 0; bs->rescue_workqueue = alloc_workqueue("bioset", WQ_MEM_RECLAIM, 0); if (!bs->rescue_workqueue) goto bad; return 0; bad: bioset_exit(bs); return -ENOMEM; } EXPORT_SYMBOL(bioset_init); /* * Initialize and setup a new bio_set, based on the settings from * another bio_set. */ int bioset_init_from_src(struct bio_set *bs, struct bio_set *src) { int flags; flags = 0; if (src->bvec_pool.min_nr) flags |= BIOSET_NEED_BVECS; if (src->rescue_workqueue) flags |= BIOSET_NEED_RESCUER; return bioset_init(bs, src->bio_pool.min_nr, src->front_pad, flags); } EXPORT_SYMBOL(bioset_init_from_src); 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); } if (bioset_init(&fs_bio_set, BIO_POOL_SIZE, 0, BIOSET_NEED_BVECS)) 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);