/* * bio-integrity.c - bio data integrity extensions * * Copyright (C) 2007, 2008 Oracle Corporation * Written by: Martin K. Petersen <martin.petersen@oracle.com> * * This program is free software; you can redistribute it and/or * modify it under the terms of the GNU General Public License version * 2 as published by the Free Software Foundation. * * This program is distributed in the hope that it will be useful, but * WITHOUT ANY WARRANTY; without even the implied warranty of * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU * General Public License for more details. * * You should have received a copy of the GNU General Public License * along with this program; see the file COPYING. If not, write to * the Free Software Foundation, 675 Mass Ave, Cambridge, MA 02139, * USA. * */ #include <linux/blkdev.h> #include <linux/mempool.h> #include <linux/bio.h> #include <linux/workqueue.h> static struct kmem_cache *bio_integrity_slab __read_mostly; static mempool_t *bio_integrity_pool; static struct bio_set *integrity_bio_set; static struct workqueue_struct *kintegrityd_wq; /** * bio_integrity_alloc - Allocate integrity payload and attach it to bio * @bio: bio to attach integrity metadata to * @gfp_mask: Memory allocation mask * @nr_vecs: Number of integrity metadata scatter-gather elements * * Description: This function prepares a bio for attaching integrity * metadata. nr_vecs specifies the maximum number of pages containing * integrity metadata that can be attached. */ struct bio_integrity_payload *bio_integrity_alloc(struct bio *bio, gfp_t gfp_mask, unsigned int nr_vecs) { struct bio_integrity_payload *bip; struct bio_vec *iv; unsigned long idx; BUG_ON(bio == NULL); bip = mempool_alloc(bio_integrity_pool, gfp_mask); if (unlikely(bip == NULL)) { printk(KERN_ERR "%s: could not alloc bip\n", __func__); return NULL; } memset(bip, 0, sizeof(*bip)); iv = bvec_alloc_bs(gfp_mask, nr_vecs, &idx, integrity_bio_set); if (unlikely(iv == NULL)) { printk(KERN_ERR "%s: could not alloc bip_vec\n", __func__); mempool_free(bip, bio_integrity_pool); return NULL; } bip->bip_pool = idx; bip->bip_vec = iv; bip->bip_bio = bio; bio->bi_integrity = bip; return bip; } EXPORT_SYMBOL(bio_integrity_alloc); /** * bio_integrity_free - Free bio integrity payload * @bio: bio containing bip to be freed * * Description: Used to free the integrity portion of a bio. Usually * called from bio_free(). */ void bio_integrity_free(struct bio *bio) { struct bio_integrity_payload *bip = bio->bi_integrity; BUG_ON(bip == NULL); /* A cloned bio doesn't own the integrity metadata */ if (!bio_flagged(bio, BIO_CLONED) && !bio_flagged(bio, BIO_FS_INTEGRITY) && bip->bip_buf != NULL) kfree(bip->bip_buf); bvec_free_bs(integrity_bio_set, bip->bip_vec, bip->bip_pool); mempool_free(bip, bio_integrity_pool); bio->bi_integrity = NULL; } EXPORT_SYMBOL(bio_integrity_free); /** * bio_integrity_add_page - Attach integrity metadata * @bio: bio to update * @page: page containing integrity metadata * @len: number of bytes of integrity metadata in page * @offset: start offset within page * * Description: Attach a page containing integrity metadata to bio. */ int bio_integrity_add_page(struct bio *bio, struct page *page, unsigned int len, unsigned int offset) { struct bio_integrity_payload *bip = bio->bi_integrity; struct bio_vec *iv; if (bip->bip_vcnt >= bvec_nr_vecs(bip->bip_pool)) { printk(KERN_ERR "%s: bip_vec full\n", __func__); return 0; } iv = bip_vec_idx(bip, bip->bip_vcnt); BUG_ON(iv == NULL); iv->bv_page = page; iv->bv_len = len; iv->bv_offset = offset; bip->bip_vcnt++; return len; } EXPORT_SYMBOL(bio_integrity_add_page); static int bdev_integrity_enabled(struct block_device *bdev, int rw) { struct blk_integrity *bi = bdev_get_integrity(bdev); if (bi == NULL) return 0; if (rw == READ && bi->verify_fn != NULL && (bi->flags & INTEGRITY_FLAG_READ)) return 1; if (rw == WRITE && bi->generate_fn != NULL && (bi->flags & INTEGRITY_FLAG_WRITE)) return 1; return 0; } /** * bio_integrity_enabled - Check whether integrity can be passed * @bio: bio to check * * Description: Determines whether bio_integrity_prep() can be called * on this bio or not. bio data direction and target device must be * set prior to calling. The functions honors the write_generate and * read_verify flags in sysfs. */ int bio_integrity_enabled(struct bio *bio) { /* Already protected? */ if (bio_integrity(bio)) return 0; return bdev_integrity_enabled(bio->bi_bdev, bio_data_dir(bio)); } EXPORT_SYMBOL(bio_integrity_enabled); /** * bio_integrity_hw_sectors - Convert 512b sectors to hardware ditto * @bi: blk_integrity profile for device * @sectors: Number of 512 sectors to convert * * Description: The block layer calculates everything in 512 byte * sectors but integrity metadata is done in terms of the hardware * sector size of the storage device. Convert the block layer sectors * to physical sectors. */ static inline unsigned int bio_integrity_hw_sectors(struct blk_integrity *bi, unsigned int sectors) { /* At this point there are only 512b or 4096b DIF/EPP devices */ if (bi->sector_size == 4096) return sectors >>= 3; return sectors; } /** * bio_integrity_tag_size - Retrieve integrity tag space * @bio: bio to inspect * * Description: Returns the maximum number of tag bytes that can be * attached to this bio. Filesystems can use this to determine how * much metadata to attach to an I/O. */ unsigned int bio_integrity_tag_size(struct bio *bio) { struct blk_integrity *bi = bdev_get_integrity(bio->bi_bdev); BUG_ON(bio->bi_size == 0); return bi->tag_size * (bio->bi_size / bi->sector_size); } EXPORT_SYMBOL(bio_integrity_tag_size); int bio_integrity_tag(struct bio *bio, void *tag_buf, unsigned int len, int set) { struct bio_integrity_payload *bip = bio->bi_integrity; struct blk_integrity *bi = bdev_get_integrity(bio->bi_bdev); unsigned int nr_sectors; BUG_ON(bip->bip_buf == NULL); if (bi->tag_size == 0) return -1; nr_sectors = bio_integrity_hw_sectors(bi, DIV_ROUND_UP(len, bi->tag_size)); if (nr_sectors * bi->tuple_size > bip->bip_size) { printk(KERN_ERR "%s: tag too big for bio: %u > %u\n", __func__, nr_sectors * bi->tuple_size, bip->bip_size); return -1; } if (set) bi->set_tag_fn(bip->bip_buf, tag_buf, nr_sectors); else bi->get_tag_fn(bip->bip_buf, tag_buf, nr_sectors); return 0; } /** * bio_integrity_set_tag - Attach a tag buffer to a bio * @bio: bio to attach buffer to * @tag_buf: Pointer to a buffer containing tag data * @len: Length of the included buffer * * Description: Use this function to tag a bio by leveraging the extra * space provided by devices formatted with integrity protection. The * size of the integrity buffer must be <= to the size reported by * bio_integrity_tag_size(). */ int bio_integrity_set_tag(struct bio *bio, void *tag_buf, unsigned int len) { BUG_ON(bio_data_dir(bio) != WRITE); return bio_integrity_tag(bio, tag_buf, len, 1); } EXPORT_SYMBOL(bio_integrity_set_tag); /** * bio_integrity_get_tag - Retrieve a tag buffer from a bio * @bio: bio to retrieve buffer from * @tag_buf: Pointer to a buffer for the tag data * @len: Length of the target buffer * * Description: Use this function to retrieve the tag buffer from a * completed I/O. The size of the integrity buffer must be <= to the * size reported by bio_integrity_tag_size(). */ int bio_integrity_get_tag(struct bio *bio, void *tag_buf, unsigned int len) { BUG_ON(bio_data_dir(bio) != READ); return bio_integrity_tag(bio, tag_buf, len, 0); } EXPORT_SYMBOL(bio_integrity_get_tag); /** * bio_integrity_generate - Generate integrity metadata for a bio * @bio: bio to generate integrity metadata for * * Description: Generates integrity metadata for a bio by calling the * block device's generation callback function. The bio must have a * bip attached with enough room to accommodate the generated * integrity metadata. */ static void bio_integrity_generate(struct bio *bio) { struct blk_integrity *bi = bdev_get_integrity(bio->bi_bdev); struct blk_integrity_exchg bix; struct bio_vec *bv; sector_t sector = bio->bi_sector; unsigned int i, sectors, total; void *prot_buf = bio->bi_integrity->bip_buf; total = 0; bix.disk_name = bio->bi_bdev->bd_disk->disk_name; bix.sector_size = bi->sector_size; bio_for_each_segment(bv, bio, i) { void *kaddr = kmap_atomic(bv->bv_page, KM_USER0); bix.data_buf = kaddr + bv->bv_offset; bix.data_size = bv->bv_len; bix.prot_buf = prot_buf; bix.sector = sector; bi->generate_fn(&bix); sectors = bv->bv_len / bi->sector_size; sector += sectors; prot_buf += sectors * bi->tuple_size; total += sectors * bi->tuple_size; BUG_ON(total > bio->bi_integrity->bip_size); kunmap_atomic(kaddr, KM_USER0); } } static inline unsigned short blk_integrity_tuple_size(struct blk_integrity *bi) { if (bi) return bi->tuple_size; return 0; } /** * bio_integrity_prep - Prepare bio for integrity I/O * @bio: bio to prepare * * Description: Allocates a buffer for integrity metadata, maps the * pages and attaches them to a bio. The bio must have data * direction, target device and start sector set priot to calling. In * the WRITE case, integrity metadata will be generated using the * block device's integrity function. In the READ case, the buffer * will be prepared for DMA and a suitable end_io handler set up. */ int bio_integrity_prep(struct bio *bio) { struct bio_integrity_payload *bip; struct blk_integrity *bi; struct request_queue *q; void *buf; unsigned long start, end; unsigned int len, nr_pages; unsigned int bytes, offset, i; unsigned int sectors; bi = bdev_get_integrity(bio->bi_bdev); q = bdev_get_queue(bio->bi_bdev); BUG_ON(bi == NULL); BUG_ON(bio_integrity(bio)); sectors = bio_integrity_hw_sectors(bi, bio_sectors(bio)); /* Allocate kernel buffer for protection data */ len = sectors * blk_integrity_tuple_size(bi); buf = kmalloc(len, GFP_NOIO | __GFP_NOFAIL | q->bounce_gfp); if (unlikely(buf == NULL)) { printk(KERN_ERR "could not allocate integrity buffer\n"); return -EIO; } end = (((unsigned long) buf) + len + PAGE_SIZE - 1) >> PAGE_SHIFT; start = ((unsigned long) buf) >> PAGE_SHIFT; nr_pages = end - start; /* Allocate bio integrity payload and integrity vectors */ bip = bio_integrity_alloc(bio, GFP_NOIO, nr_pages); if (unlikely(bip == NULL)) { printk(KERN_ERR "could not allocate data integrity bioset\n"); kfree(buf); return -EIO; } bip->bip_buf = buf; bip->bip_size = len; bip->bip_sector = bio->bi_sector; /* Map it */ offset = offset_in_page(buf); for (i = 0 ; i < nr_pages ; i++) { int ret; bytes = PAGE_SIZE - offset; if (len <= 0) break; if (bytes > len) bytes = len; ret = bio_integrity_add_page(bio, virt_to_page(buf), bytes, offset); if (ret == 0) return 0; if (ret < bytes) break; buf += bytes; len -= bytes; offset = 0; } /* Install custom I/O completion handler if read verify is enabled */ if (bio_data_dir(bio) == READ) { bip->bip_end_io = bio->bi_end_io; bio->bi_end_io = bio_integrity_endio; } /* Auto-generate integrity metadata if this is a write */ if (bio_data_dir(bio) == WRITE) bio_integrity_generate(bio); return 0; } EXPORT_SYMBOL(bio_integrity_prep); /** * bio_integrity_verify - Verify integrity metadata for a bio * @bio: bio to verify * * Description: This function is called to verify the integrity of a * bio. The data in the bio io_vec is compared to the integrity * metadata returned by the HBA. */ static int bio_integrity_verify(struct bio *bio) { struct blk_integrity *bi = bdev_get_integrity(bio->bi_bdev); struct blk_integrity_exchg bix; struct bio_vec *bv; sector_t sector = bio->bi_integrity->bip_sector; unsigned int i, sectors, total, ret; void *prot_buf = bio->bi_integrity->bip_buf; ret = total = 0; bix.disk_name = bio->bi_bdev->bd_disk->disk_name; bix.sector_size = bi->sector_size; bio_for_each_segment(bv, bio, i) { void *kaddr = kmap_atomic(bv->bv_page, KM_USER0); bix.data_buf = kaddr + bv->bv_offset; bix.data_size = bv->bv_len; bix.prot_buf = prot_buf; bix.sector = sector; ret = bi->verify_fn(&bix); if (ret) { kunmap_atomic(kaddr, KM_USER0); return ret; } sectors = bv->bv_len / bi->sector_size; sector += sectors; prot_buf += sectors * bi->tuple_size; total += sectors * bi->tuple_size; BUG_ON(total > bio->bi_integrity->bip_size); kunmap_atomic(kaddr, KM_USER0); } return ret; } /** * bio_integrity_verify_fn - Integrity I/O completion worker * @work: Work struct stored in bio to be verified * * Description: This workqueue function is called to complete a READ * request. The function verifies the transferred integrity metadata * and then calls the original bio end_io function. */ static void bio_integrity_verify_fn(struct work_struct *work) { struct bio_integrity_payload *bip = container_of(work, struct bio_integrity_payload, bip_work); struct bio *bio = bip->bip_bio; int error; error = bio_integrity_verify(bio); /* Restore original bio completion handler */ bio->bi_end_io = bip->bip_end_io; bio_endio(bio, error); } /** * bio_integrity_endio - Integrity I/O completion function * @bio: Protected bio * @error: Pointer to errno * * Description: Completion for integrity I/O * * Normally I/O completion is done in interrupt context. However, * verifying I/O integrity is a time-consuming task which must be run * in process context. This function postpones completion * accordingly. */ void bio_integrity_endio(struct bio *bio, int error) { struct bio_integrity_payload *bip = bio->bi_integrity; BUG_ON(bip->bip_bio != bio); /* In case of an I/O error there is no point in verifying the * integrity metadata. Restore original bio end_io handler * and run it. */ if (error) { bio->bi_end_io = bip->bip_end_io; bio_endio(bio, error); return; } INIT_WORK(&bip->bip_work, bio_integrity_verify_fn); queue_work(kintegrityd_wq, &bip->bip_work); } EXPORT_SYMBOL(bio_integrity_endio); /** * bio_integrity_mark_head - Advance bip_vec skip bytes * @bip: Integrity vector to advance * @skip: Number of bytes to advance it */ void bio_integrity_mark_head(struct bio_integrity_payload *bip, unsigned int skip) { struct bio_vec *iv; unsigned int i; bip_for_each_vec(iv, bip, i) { if (skip == 0) { bip->bip_idx = i; return; } else if (skip >= iv->bv_len) { skip -= iv->bv_len; } else { /* skip < iv->bv_len) */ iv->bv_offset += skip; iv->bv_len -= skip; bip->bip_idx = i; return; } } } /** * bio_integrity_mark_tail - Truncate bip_vec to be len bytes long * @bip: Integrity vector to truncate * @len: New length of integrity vector */ void bio_integrity_mark_tail(struct bio_integrity_payload *bip, unsigned int len) { struct bio_vec *iv; unsigned int i; bip_for_each_vec(iv, bip, i) { if (len == 0) { bip->bip_vcnt = i; return; } else if (len >= iv->bv_len) { len -= iv->bv_len; } else { /* len < iv->bv_len) */ iv->bv_len = len; len = 0; } } } /** * bio_integrity_advance - Advance integrity vector * @bio: bio whose integrity vector to update * @bytes_done: number of data bytes that have been completed * * Description: This function calculates how many integrity bytes the * number of completed data bytes correspond to and advances the * integrity vector accordingly. */ void bio_integrity_advance(struct bio *bio, unsigned int bytes_done) { struct bio_integrity_payload *bip = bio->bi_integrity; struct blk_integrity *bi = bdev_get_integrity(bio->bi_bdev); unsigned int nr_sectors; BUG_ON(bip == NULL); BUG_ON(bi == NULL); nr_sectors = bio_integrity_hw_sectors(bi, bytes_done >> 9); bio_integrity_mark_head(bip, nr_sectors * bi->tuple_size); } EXPORT_SYMBOL(bio_integrity_advance); /** * bio_integrity_trim - Trim integrity vector * @bio: bio whose integrity vector to update * @offset: offset to first data sector * @sectors: number of data sectors * * Description: Used to trim the integrity vector in a cloned bio. * The ivec will be advanced corresponding to 'offset' data sectors * and the length will be truncated corresponding to 'len' data * sectors. */ void bio_integrity_trim(struct bio *bio, unsigned int offset, unsigned int sectors) { struct bio_integrity_payload *bip = bio->bi_integrity; struct blk_integrity *bi = bdev_get_integrity(bio->bi_bdev); unsigned int nr_sectors; BUG_ON(bip == NULL); BUG_ON(bi == NULL); BUG_ON(!bio_flagged(bio, BIO_CLONED)); nr_sectors = bio_integrity_hw_sectors(bi, sectors); bip->bip_sector = bip->bip_sector + offset; bio_integrity_mark_head(bip, offset * bi->tuple_size); bio_integrity_mark_tail(bip, sectors * bi->tuple_size); } EXPORT_SYMBOL(bio_integrity_trim); /** * bio_integrity_split - Split integrity metadata * @bio: Protected bio * @bp: Resulting bio_pair * @sectors: Offset * * Description: Splits an integrity page into a bio_pair. */ void bio_integrity_split(struct bio *bio, struct bio_pair *bp, int sectors) { struct blk_integrity *bi; struct bio_integrity_payload *bip = bio->bi_integrity; unsigned int nr_sectors; if (bio_integrity(bio) == 0) return; bi = bdev_get_integrity(bio->bi_bdev); BUG_ON(bi == NULL); BUG_ON(bip->bip_vcnt != 1); nr_sectors = bio_integrity_hw_sectors(bi, sectors); bp->bio1.bi_integrity = &bp->bip1; bp->bio2.bi_integrity = &bp->bip2; bp->iv1 = bip->bip_vec[0]; bp->iv2 = bip->bip_vec[0]; bp->bip1.bip_vec = &bp->iv1; bp->bip2.bip_vec = &bp->iv2; bp->iv1.bv_len = sectors * bi->tuple_size; bp->iv2.bv_offset += sectors * bi->tuple_size; bp->iv2.bv_len -= sectors * bi->tuple_size; bp->bip1.bip_sector = bio->bi_integrity->bip_sector; bp->bip2.bip_sector = bio->bi_integrity->bip_sector + nr_sectors; bp->bip1.bip_vcnt = bp->bip2.bip_vcnt = 1; bp->bip1.bip_idx = bp->bip2.bip_idx = 0; } EXPORT_SYMBOL(bio_integrity_split); /** * bio_integrity_clone - Callback for cloning bios with integrity metadata * @bio: New bio * @bio_src: Original bio * @gfp_mask: Memory allocation mask * * Description: Called to allocate a bip when cloning a bio */ int bio_integrity_clone(struct bio *bio, struct bio *bio_src, gfp_t gfp_mask) { struct bio_integrity_payload *bip_src = bio_src->bi_integrity; struct bio_integrity_payload *bip; BUG_ON(bip_src == NULL); bip = bio_integrity_alloc(bio, gfp_mask, bip_src->bip_vcnt); if (bip == NULL) return -EIO; memcpy(bip->bip_vec, bip_src->bip_vec, bip_src->bip_vcnt * sizeof(struct bio_vec)); bip->bip_sector = bip_src->bip_sector; bip->bip_vcnt = bip_src->bip_vcnt; bip->bip_idx = bip_src->bip_idx; return 0; } EXPORT_SYMBOL(bio_integrity_clone); static int __init bio_integrity_init(void) { kintegrityd_wq = create_workqueue("kintegrityd"); if (!kintegrityd_wq) panic("Failed to create kintegrityd\n"); bio_integrity_slab = KMEM_CACHE(bio_integrity_payload, SLAB_HWCACHE_ALIGN|SLAB_PANIC); bio_integrity_pool = mempool_create_slab_pool(BIO_POOL_SIZE, bio_integrity_slab); if (!bio_integrity_pool) panic("bio_integrity: can't allocate bip pool\n"); integrity_bio_set = bioset_create(BIO_POOL_SIZE, 0); if (!integrity_bio_set) panic("bio_integrity: can't allocate bio_set\n"); return 0; } subsys_initcall(bio_integrity_init);