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/*
* 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>
#include "blk.h"
#define BIP_INLINE_VECS 4
static struct kmem_cache *bip_slab;
static struct workqueue_struct *kintegrityd_wq;
void blk_flush_integrity(void)
{
flush_workqueue(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 inline_vecs;
if (!bs || !bs->bio_integrity_pool) {
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 ERR_PTR(-ENOMEM);
memset(bip, 0, sizeof(*bip));
if (nr_vecs > inline_vecs) {
unsigned long idx = 0;
bip->bip_vec = bvec_alloc(gfp_mask, nr_vecs, &idx,
bs->bvec_integrity_pool);
if (!bip->bip_vec)
goto err;
bip->bip_max_vcnt = bvec_nr_vecs(idx);
bip->bip_slab = idx;
} else {
bip->bip_vec = bip->bip_inline_vecs;
bip->bip_max_vcnt = inline_vecs;
}
bip->bip_bio = bio;
bio->bi_integrity = bip;
bio->bi_opf |= REQ_INTEGRITY;
return bip;
err:
mempool_free(bip, bs->bio_integrity_pool);
return ERR_PTR(-ENOMEM);
}
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_integrity(bio);
struct bio_set *bs = bio->bi_pool;
if (bip->bip_flags & BIP_BLOCK_INTEGRITY)
kfree(page_address(bip->bip_vec->bv_page) +
bip->bip_vec->bv_offset);
if (bs && bs->bio_integrity_pool) {
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_integrity(bio);
struct bio_vec *iv;
if (bip->bip_vcnt >= bip->bip_max_vcnt) {
printk(KERN_ERR "%s: bip_vec full\n", __func__);
return 0;
}
iv = bip->bip_vec + bip->bip_vcnt;
if (bip->bip_vcnt &&
bvec_gap_to_prev(bdev_get_queue(bio->bi_bdev),
&bip->bip_vec[bip->bip_vcnt - 1], offset))
return 0;
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.
*/
bool bio_integrity_enabled(struct bio *bio)
{
struct blk_integrity *bi = bdev_get_integrity(bio->bi_bdev);
if (bio_op(bio) != REQ_OP_READ && bio_op(bio) != REQ_OP_WRITE)
return false;
if (!bio_sectors(bio))
return false;
/* Already protected? */
if (bio_integrity(bio))
return false;
if (bi == NULL)
return false;
if (bio_data_dir(bio) == READ && bi->profile->verify_fn != NULL &&
(bi->flags & BLK_INTEGRITY_VERIFY))
return true;
if (bio_data_dir(bio) == WRITE && bi->profile->generate_fn != NULL &&
(bi->flags & BLK_INTEGRITY_GENERATE))
return true;
return false;
}
EXPORT_SYMBOL(bio_integrity_enabled);
/**
* bio_integrity_intervals - Return number of integrity intervals for a bio
* @bi: blk_integrity profile for device
* @sectors: Size of the bio in 512-byte sectors
*
* Description: The block layer calculates everything in 512 byte
* sectors but integrity metadata is done in terms of the data integrity
* interval size of the storage device. Convert the block layer sectors
* to the appropriate number of integrity intervals.
*/
static inline unsigned int bio_integrity_intervals(struct blk_integrity *bi,
unsigned int sectors)
{
return sectors >> (bi->interval_exp - 9);
}
static inline unsigned int bio_integrity_bytes(struct blk_integrity *bi,
unsigned int sectors)
{
return bio_integrity_intervals(bi, sectors) * bi->tuple_size;
}
/**
* bio_integrity_process - Process integrity metadata for a bio
* @bio: bio to generate/verify integrity metadata for
* @proc_fn: Pointer to the relevant processing function
*/
static blk_status_t bio_integrity_process(struct bio *bio,
integrity_processing_fn *proc_fn)
{
struct blk_integrity *bi = bdev_get_integrity(bio->bi_bdev);
struct blk_integrity_iter iter;
struct bvec_iter bviter;
struct bio_vec bv;
struct bio_integrity_payload *bip = bio_integrity(bio);
blk_status_t ret = BLK_STS_OK;
void *prot_buf = page_address(bip->bip_vec->bv_page) +
bip->bip_vec->bv_offset;
iter.disk_name = bio->bi_bdev->bd_disk->disk_name;
iter.interval = 1 << bi->interval_exp;
iter.seed = bip_get_seed(bip);
iter.prot_buf = prot_buf;
bio_for_each_segment(bv, bio, bviter) {
void *kaddr = kmap_atomic(bv.bv_page);
iter.data_buf = kaddr + bv.bv_offset;
iter.data_size = bv.bv_len;
ret = proc_fn(&iter);
if (ret) {
kunmap_atomic(kaddr);
return ret;
}
kunmap_atomic(kaddr);
}
return ret;
}
/**
* 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)
{
|