/* * bio-integrity.c - bio data integrity extensions * * Copyright (C) 2007, 2008, 2009 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/export.h> #include <linux/bio.h> #include <linux/workqueue.h> #include <linux/slab.h> #define BIP_INLINE_VECS 4 static struct kmem_cache *bip_slab; 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_set *bs = bio->bi_pool; unsigned long idx = BIO_POOL_NONE; unsigned inline_vecs; if (!bs) { bip = kmalloc(sizeof(struct bio_integrity_payload) + sizeof(struct bio_vec) * nr_vecs, gfp_mask); inline_vecs = nr_vecs; } else { bip = mempool_alloc(bs->bio_integrity_pool, gfp_mask); inline_vecs = BIP_INLINE_VECS; } if (unlikely(!bip)) return NULL; memset(bip, 0, sizeof(*bip)); if (nr_vecs > inline_vecs) { bip->bip_vec = bvec_alloc(gfp_mask, nr_vecs, &idx, bs->bvec_integrity_pool); if (!bip->bip_vec) goto err; } else { bip->bip_vec = bip->bip_inline_vecs; } bip->bip_slab = idx; bip->bip_bio = bio; bio->bi_integrity = bip; return bip; err: mempool_free(bip, bs->bio_integrity_pool); return NULL; } 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; struct bio_set *bs = bio->bi_pool; if (bip->bip_owns_buf) kfree(bip->bip_buf); if (bs) { if (bip->bip_slab != BIO_POOL_NONE) bvec_free(bs->bvec_integrity_pool, bip->bip_vec, bip->bip_slab); mempool_free(bip, bs->bio_integrity_pool); } else { kfree(bip); } bio->bi_integrity = NULL; } EXPORT_SYMBOL(bio_integrity_free); static inline unsigned int bip_integrity_vecs(struct bio_integrity_payload *bip) { if (bip->bip_slab == BIO_POOL_NONE) return BIP_INLINE_VECS; return bvec_nr_vecs(bip->bip_slab); } /** * 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 >= bip_integrity_vecs(bip)) { printk(KERN_ERR "%s: bip_vec full\n", __func__); return 0; } iv = bip->bip_vec + bip->bip_vcnt; 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; } static inline unsigned int bio_integrity_bytes(struct blk_integrity *bi, unsigned int sectors) { return bio_integrity_hw_sectors(bi, sectors) * bi->tuple_size; } /** * 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_iter.bi_size == 0); return bi->tag_size * (bio->bi_iter.bi_size / bi->sector_size); } EXPORT_SYMBOL(bio_integrity_tag_size); static 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_iter.bi_size) { printk(KERN_ERR "%s: tag too big for bio: %u > %u\n", __func__, nr_sectors * bi->tuple_size, bip->bip_iter.bi_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_verify - Generate/verify integrity metadata for a bio * @bio: bio to generate/verify integrity metadata for * @operate: operate number, 1 for generate, 0 for verify */ static int bio_integrity_generate_verify(struct bio *bio, int operate) { struct blk_integrity *bi = bdev_get_integrity(bio->bi_bdev); struct blk_integrity_exchg bix; struct bio_vec bv; struct bvec_iter iter; sector_t sector; unsigned int sectors, ret = 0; void *prot_buf = bio->bi_integrity->bip_buf; if (operate) sector = bio->bi_iter.bi_sector; else sector = bio->bi_integrity->bip_iter.bi_sector; bix.disk_name = bio->bi_bdev->bd_disk->disk_name; bix.sector_size = bi->sector_size; bio_for_each_segment(bv, bio, iter) { void *kaddr = kmap_atomic(bv.bv_page); bix.data_buf = kaddr + bv.bv_offset; bix.data_size = bv.bv_len; bix.prot_buf = prot_buf; bix.sector = sector; if (operate) { bi->generate_fn(&bix); } else { ret = bi->verify_fn(&bix); if (ret) { kunmap_atomic(kaddr); return ret; } } sectors = bv.bv_len / bi->sector_size; sector += sectors; prot_buf += sectors * bi->tuple_size; kunmap_atomic(kaddr); } return ret; } /** * 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) { bio_integrity_generate_verify(bio, 1); } 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 | q->bounce_gfp); if (unlikely(buf == NULL)) { printk(KERN_ERR "could not allocate integrity buffer\n"); return -ENOMEM; } 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_owns_buf = 1; bip->bip_buf = buf; bip->bip_iter.bi_size = len; bip->bip_iter.bi_sector = bio->bi_iter.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) { return bio_integrity_generate_verify(bio, 0); } /** * 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_nodec(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_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 bytes = bio_integrity_bytes(bi, bytes_done >> 9); bvec_iter_advance(bip->bip_vec, &bip->bip_iter, bytes); } 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); bio_integrity_advance(bio, offset << 9); bip->bip_iter.bi_size = bio_integrity_bytes(bi, sectors); } EXPORT_SYMBOL(bio_integrity_trim); /** * 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_vcnt = bip_src->bip_vcnt; bip->bip_iter = bip_src->bip_iter; return 0; } EXPORT_SYMBOL(bio_integrity_clone); int bioset_integrity_create(struct bio_set *bs, int pool_size) { if (bs->bio_integrity_pool) return 0; bs->bio_integrity_pool = mempool_create_slab_pool(pool_size, bip_slab); if (!bs->bio_integrity_pool) return -1; bs->bvec_integrity_pool = biovec_create_pool(bs, pool_size); if (!bs->bvec_integrity_pool) { mempool_destroy(bs->bio_integrity_pool); return -1; } return 0; } EXPORT_SYMBOL(bioset_integrity_create); void bioset_integrity_free(struct bio_set *bs) { if (bs->bio_integrity_pool) mempool_destroy(bs->bio_integrity_pool); if (bs->bvec_integrity_pool) mempool_destroy(bs->bvec_integrity_pool); } EXPORT_SYMBOL(bioset_integrity_free); void __init bio_integrity_init(void) { /* * kintegrityd won't block much but may burn a lot of CPU cycles. * Make it highpri CPU intensive wq with max concurrency of 1. */ kintegrityd_wq = alloc_workqueue("kintegrityd", WQ_MEM_RECLAIM | WQ_HIGHPRI | WQ_CPU_INTENSIVE, 1); if (!kintegrityd_wq) panic("Failed to create kintegrityd\n"); bip_slab = kmem_cache_create("bio_integrity_payload", sizeof(struct bio_integrity_payload) + sizeof(struct bio_vec) * BIP_INLINE_VECS, 0, SLAB_HWCACHE_ALIGN|SLAB_PANIC, NULL); if (!bip_slab) panic("Failed to create slab\n"); }