block: Block layer data integrity support

Some block devices support verifying the integrity of requests by way
of checksums or other protection information that is submitted along
with the I/O.

This patch implements support for generating and verifying integrity
metadata, as well as correctly merging, splitting and cloning bios and
requests that have this extra information attached.

See Documentation/block/data-integrity.txt for more information.

Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>
Signed-off-by: Jens Axboe <jens.axboe@oracle.com>

1 files changed, 708 insertions, 0 deletions

diff --git a/fs/bio-integrity.c b/fs/bio-integrity.c
new file mode 100644
index 000000000000..31b08878913d
--- /dev/null
+++ b/fs/bio-integrity.c
@@ -0,0 +1,708 @@
+/*
+ * 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 struct workqueue_struct *kintegrityd_wq;
+
+/**
+ * bio_integrity_alloc_bioset - 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
+ * @bs:         bio_set to allocate from
+ *
+ * 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_bioset(struct bio *bio, gfp_t gfp_mask, unsigned int nr_vecs, struct bio_set *bs)
+{
+        struct bio_integrity_payload *bip;
+        struct bio_vec *iv;
+        unsigned long idx;
+
+        BUG_ON(bio == NULL);
+
+        bip = mempool_alloc(bs->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, bs);
+        if (unlikely(iv == NULL)) {
+                printk(KERN_ERR "%s: could not alloc bip_vec\n", __func__);
+                mempool_free(bip, bs->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_bioset);
+
+/**
+ * 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)
+{
+        return bio_integrity_alloc_bioset(bio, gfp_mask, nr_vecs, fs_bio_set);
+}
+EXPORT_SYMBOL(bio_integrity_alloc);
+
+/**
+ * bio_integrity_free - Free bio integrity payload
+ * @bio:        bio containing bip to be freed
+ * @bs:         bio_set this bio was allocated from
+ *
+ * Description: Used to free the integrity portion of a bio. Usually
+ * called from bio_free().
+ */
+void bio_integrity_free(struct bio *bio, struct bio_set *bs)
+{
+        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) && bip->bip_buf != NULL)
+                kfree(bip->bip_buf);
+
+        mempool_free(bip->bip_vec, bs->bvec_pools[bip->bip_pool]);
+        mempool_free(bip, bs->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);
+        BUG_ON(iv->bv_page != NULL);
+
+        iv->bv_page = page;
+        iv->bv_len = len;
+        iv->bv_offset = offset;
+        bip->bip_vcnt++;
+
+        return len;
+}
+EXPORT_SYMBOL(bio_integrity_add_page);
+
+/**
+ * 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);
+        }
+}
+
+/**
+ * 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);
+                        break;
+                }
+
+                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 = bip->bip_error;
+
+        if (bio_integrity_verify(bio)) {
+                clear_bit(BIO_UPTODATE, &bio->bi_flags);
+                error = -EIO;
+        }
+
+        /* Restore original bio completion handler */
+        bio->bi_end_io = bip->bip_end_io;
+
+        if (bio->bi_end_io)
+                bio->bi_end_io(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);
+
+        bip->bip_error = error;
+        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
+ * @bs:         bio_set to allocate bip from
+ *
+ * Description: Called to allocate a bip when cloning a bio
+ */
+int bio_integrity_clone(struct bio *bio, struct bio *bio_src, struct bio_set *bs)
+{
+        struct bio_integrity_payload *bip_src = bio_src->bi_integrity;
+        struct bio_integrity_payload *bip;
+
+        BUG_ON(bip_src == NULL);
+
+        bip = bio_integrity_alloc_bioset(bio, GFP_NOIO, bip_src->bip_vcnt, bs);
+
+        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);
+
+int bioset_integrity_create(struct bio_set *bs, int pool_size)
+{
+        bs->bio_integrity_pool = mempool_create_slab_pool(pool_size,
+                                                          bio_integrity_slab);
+        if (!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);
+}
+EXPORT_SYMBOL(bioset_integrity_free);
+
+void __init bio_integrity_init_slab(void)
+{
+        bio_integrity_slab = KMEM_CACHE(bio_integrity_payload,
+                                        SLAB_HWCACHE_ALIGN|SLAB_PANIC);
+}
+EXPORT_SYMBOL(bio_integrity_init_slab);
+
+static int __init integrity_init(void)
+{
+        kintegrityd_wq = create_workqueue("kintegrityd");
+
+        if (!kintegrityd_wq)
+                panic("Failed to create kintegrityd\n");
+
+        return 0;
+}
+subsys_initcall(integrity_init);