/*
* 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);
/**
* 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_slab)) {
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);
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);
}
}
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_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);
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);
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);
}
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[bip->bip_idx];
bp->iv2 = bip->bip_vec[bip->bip_idx];
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);
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);
bs->bvec_integrity_pool = biovec_create_pool(bs, pool_size);
if (!bs->bvec_integrity_pool)
return -1;
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);
if (bs->bvec_integrity_pool)
mempool_destroy(bs->bio_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");
}
