![Martin K. Petersen](/assets/img/avatar_default.png)
Make the choice of checksum a per-I/O property by introducing a flag that can be inspected by the SCSI layer. There are several reasons for this: 1. It allows us to switch choice of checksum without unloading and reloading the HBA driver. 2. During error recovery we need to be able to tell the HBA that checksums read from disk should not be verified and converted to IP checksums. 3. For error injection purposes we need to be able to write a bad guard tag to storage. Since the storage device only supports T10 CRC we need to be able to disable IP checksum conversion on the HBA. Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com> Reviewed-by: Sagi Grimberg <sagig@mellanox.com> Signed-off-by: Jens Axboe <axboe@fb.com>
519 lines
14 KiB
C
519 lines
14 KiB
C
/*
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* bio-integrity.c - bio data integrity extensions
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*
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* Copyright (C) 2007, 2008, 2009 Oracle Corporation
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* Written by: Martin K. Petersen <martin.petersen@oracle.com>
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*
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* This program is free software; you can redistribute it and/or
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* modify it under the terms of the GNU General Public License version
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* 2 as published by the Free Software Foundation.
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*
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* This program is distributed in the hope that it will be useful, but
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* WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
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* General Public License for more details.
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*
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* You should have received a copy of the GNU General Public License
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* along with this program; see the file COPYING. If not, write to
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* the Free Software Foundation, 675 Mass Ave, Cambridge, MA 02139,
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* USA.
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*
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*/
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#include <linux/blkdev.h>
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#include <linux/mempool.h>
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#include <linux/export.h>
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#include <linux/bio.h>
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#include <linux/workqueue.h>
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#include <linux/slab.h>
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#define BIP_INLINE_VECS 4
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static struct kmem_cache *bip_slab;
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static struct workqueue_struct *kintegrityd_wq;
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/**
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* bio_integrity_alloc - Allocate integrity payload and attach it to bio
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* @bio: bio to attach integrity metadata to
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* @gfp_mask: Memory allocation mask
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* @nr_vecs: Number of integrity metadata scatter-gather elements
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*
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* Description: This function prepares a bio for attaching integrity
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* metadata. nr_vecs specifies the maximum number of pages containing
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* integrity metadata that can be attached.
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*/
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struct bio_integrity_payload *bio_integrity_alloc(struct bio *bio,
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gfp_t gfp_mask,
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unsigned int nr_vecs)
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{
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struct bio_integrity_payload *bip;
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struct bio_set *bs = bio->bi_pool;
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unsigned long idx = BIO_POOL_NONE;
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unsigned inline_vecs;
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if (!bs) {
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bip = kmalloc(sizeof(struct bio_integrity_payload) +
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sizeof(struct bio_vec) * nr_vecs, gfp_mask);
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inline_vecs = nr_vecs;
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} else {
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bip = mempool_alloc(bs->bio_integrity_pool, gfp_mask);
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inline_vecs = BIP_INLINE_VECS;
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}
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if (unlikely(!bip))
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return NULL;
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memset(bip, 0, sizeof(*bip));
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if (nr_vecs > inline_vecs) {
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bip->bip_vec = bvec_alloc(gfp_mask, nr_vecs, &idx,
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bs->bvec_integrity_pool);
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if (!bip->bip_vec)
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goto err;
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bip->bip_max_vcnt = bvec_nr_vecs(idx);
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} else {
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bip->bip_vec = bip->bip_inline_vecs;
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bip->bip_max_vcnt = inline_vecs;
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}
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bip->bip_slab = idx;
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bip->bip_bio = bio;
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bio->bi_integrity = bip;
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bio->bi_rw |= REQ_INTEGRITY;
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return bip;
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err:
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mempool_free(bip, bs->bio_integrity_pool);
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return NULL;
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}
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EXPORT_SYMBOL(bio_integrity_alloc);
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/**
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* bio_integrity_free - Free bio integrity payload
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* @bio: bio containing bip to be freed
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*
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* Description: Used to free the integrity portion of a bio. Usually
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* called from bio_free().
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*/
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void bio_integrity_free(struct bio *bio)
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{
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struct bio_integrity_payload *bip = bio_integrity(bio);
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struct bio_set *bs = bio->bi_pool;
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if (bip->bip_flags & BIP_BLOCK_INTEGRITY)
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kfree(page_address(bip->bip_vec->bv_page) +
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bip->bip_vec->bv_offset);
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if (bs) {
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if (bip->bip_slab != BIO_POOL_NONE)
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bvec_free(bs->bvec_integrity_pool, bip->bip_vec,
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bip->bip_slab);
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mempool_free(bip, bs->bio_integrity_pool);
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} else {
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kfree(bip);
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}
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bio->bi_integrity = NULL;
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}
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EXPORT_SYMBOL(bio_integrity_free);
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/**
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* bio_integrity_add_page - Attach integrity metadata
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* @bio: bio to update
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* @page: page containing integrity metadata
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* @len: number of bytes of integrity metadata in page
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* @offset: start offset within page
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*
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* Description: Attach a page containing integrity metadata to bio.
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*/
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int bio_integrity_add_page(struct bio *bio, struct page *page,
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unsigned int len, unsigned int offset)
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{
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struct bio_integrity_payload *bip = bio_integrity(bio);
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struct bio_vec *iv;
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if (bip->bip_vcnt >= bip->bip_max_vcnt) {
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printk(KERN_ERR "%s: bip_vec full\n", __func__);
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return 0;
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}
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iv = bip->bip_vec + bip->bip_vcnt;
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iv->bv_page = page;
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iv->bv_len = len;
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iv->bv_offset = offset;
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bip->bip_vcnt++;
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return len;
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}
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EXPORT_SYMBOL(bio_integrity_add_page);
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/**
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* bio_integrity_enabled - Check whether integrity can be passed
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* @bio: bio to check
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*
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* Description: Determines whether bio_integrity_prep() can be called
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* on this bio or not. bio data direction and target device must be
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* set prior to calling. The functions honors the write_generate and
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* read_verify flags in sysfs.
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*/
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bool bio_integrity_enabled(struct bio *bio)
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{
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struct blk_integrity *bi = bdev_get_integrity(bio->bi_bdev);
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if (!bio_is_rw(bio))
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return false;
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/* Already protected? */
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if (bio_integrity(bio))
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return false;
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if (bi == NULL)
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return false;
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if (bio_data_dir(bio) == READ && bi->verify_fn != NULL &&
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(bi->flags & BLK_INTEGRITY_VERIFY))
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return true;
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if (bio_data_dir(bio) == WRITE && bi->generate_fn != NULL &&
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(bi->flags & BLK_INTEGRITY_GENERATE))
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return true;
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return false;
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}
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EXPORT_SYMBOL(bio_integrity_enabled);
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/**
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* bio_integrity_intervals - Return number of integrity intervals for a bio
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* @bi: blk_integrity profile for device
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* @sectors: Size of the bio in 512-byte sectors
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*
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* Description: The block layer calculates everything in 512 byte
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* sectors but integrity metadata is done in terms of the data integrity
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* interval size of the storage device. Convert the block layer sectors
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* to the appropriate number of integrity intervals.
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*/
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static inline unsigned int bio_integrity_intervals(struct blk_integrity *bi,
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unsigned int sectors)
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{
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return sectors >> (ilog2(bi->interval) - 9);
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}
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static inline unsigned int bio_integrity_bytes(struct blk_integrity *bi,
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unsigned int sectors)
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{
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return bio_integrity_intervals(bi, sectors) * bi->tuple_size;
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}
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/**
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* bio_integrity_process - Process integrity metadata for a bio
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* @bio: bio to generate/verify integrity metadata for
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* @proc_fn: Pointer to the relevant processing function
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*/
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static int bio_integrity_process(struct bio *bio,
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integrity_processing_fn *proc_fn)
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{
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struct blk_integrity *bi = bdev_get_integrity(bio->bi_bdev);
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struct blk_integrity_iter iter;
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struct bio_vec *bv;
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struct bio_integrity_payload *bip = bio_integrity(bio);
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unsigned int i, ret = 0;
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void *prot_buf = page_address(bip->bip_vec->bv_page) +
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bip->bip_vec->bv_offset;
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iter.disk_name = bio->bi_bdev->bd_disk->disk_name;
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iter.interval = bi->interval;
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iter.seed = bip_get_seed(bip);
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iter.prot_buf = prot_buf;
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bio_for_each_segment_all(bv, bio, i) {
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void *kaddr = kmap_atomic(bv->bv_page);
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iter.data_buf = kaddr + bv->bv_offset;
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iter.data_size = bv->bv_len;
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ret = proc_fn(&iter);
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if (ret) {
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kunmap_atomic(kaddr);
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return ret;
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}
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kunmap_atomic(kaddr);
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}
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return ret;
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}
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/**
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* bio_integrity_prep - Prepare bio for integrity I/O
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* @bio: bio to prepare
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*
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* Description: Allocates a buffer for integrity metadata, maps the
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* pages and attaches them to a bio. The bio must have data
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* direction, target device and start sector set priot to calling. In
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* the WRITE case, integrity metadata will be generated using the
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* block device's integrity function. In the READ case, the buffer
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* will be prepared for DMA and a suitable end_io handler set up.
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*/
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int bio_integrity_prep(struct bio *bio)
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{
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struct bio_integrity_payload *bip;
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struct blk_integrity *bi;
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struct request_queue *q;
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void *buf;
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unsigned long start, end;
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unsigned int len, nr_pages;
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unsigned int bytes, offset, i;
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unsigned int intervals;
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bi = bdev_get_integrity(bio->bi_bdev);
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q = bdev_get_queue(bio->bi_bdev);
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BUG_ON(bi == NULL);
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BUG_ON(bio_integrity(bio));
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intervals = bio_integrity_intervals(bi, bio_sectors(bio));
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/* Allocate kernel buffer for protection data */
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len = intervals * bi->tuple_size;
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buf = kmalloc(len, GFP_NOIO | q->bounce_gfp);
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if (unlikely(buf == NULL)) {
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printk(KERN_ERR "could not allocate integrity buffer\n");
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return -ENOMEM;
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}
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end = (((unsigned long) buf) + len + PAGE_SIZE - 1) >> PAGE_SHIFT;
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start = ((unsigned long) buf) >> PAGE_SHIFT;
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nr_pages = end - start;
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/* Allocate bio integrity payload and integrity vectors */
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bip = bio_integrity_alloc(bio, GFP_NOIO, nr_pages);
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if (unlikely(bip == NULL)) {
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printk(KERN_ERR "could not allocate data integrity bioset\n");
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kfree(buf);
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return -EIO;
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}
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bip->bip_flags |= BIP_BLOCK_INTEGRITY;
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bip->bip_iter.bi_size = len;
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bip_set_seed(bip, bio->bi_iter.bi_sector);
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if (bi->flags & BLK_INTEGRITY_IP_CHECKSUM)
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bip->bip_flags |= BIP_IP_CHECKSUM;
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/* Map it */
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offset = offset_in_page(buf);
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for (i = 0 ; i < nr_pages ; i++) {
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int ret;
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bytes = PAGE_SIZE - offset;
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if (len <= 0)
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break;
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if (bytes > len)
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bytes = len;
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ret = bio_integrity_add_page(bio, virt_to_page(buf),
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bytes, offset);
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if (ret == 0)
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return 0;
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if (ret < bytes)
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break;
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buf += bytes;
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len -= bytes;
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offset = 0;
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}
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/* Install custom I/O completion handler if read verify is enabled */
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if (bio_data_dir(bio) == READ) {
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bip->bip_end_io = bio->bi_end_io;
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bio->bi_end_io = bio_integrity_endio;
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}
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/* Auto-generate integrity metadata if this is a write */
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if (bio_data_dir(bio) == WRITE)
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bio_integrity_process(bio, bi->generate_fn);
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return 0;
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}
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EXPORT_SYMBOL(bio_integrity_prep);
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/**
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* bio_integrity_verify_fn - Integrity I/O completion worker
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* @work: Work struct stored in bio to be verified
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*
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* Description: This workqueue function is called to complete a READ
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* request. The function verifies the transferred integrity metadata
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* and then calls the original bio end_io function.
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*/
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static void bio_integrity_verify_fn(struct work_struct *work)
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{
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struct bio_integrity_payload *bip =
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container_of(work, struct bio_integrity_payload, bip_work);
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struct bio *bio = bip->bip_bio;
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struct blk_integrity *bi = bdev_get_integrity(bio->bi_bdev);
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int error;
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error = bio_integrity_process(bio, bi->verify_fn);
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/* Restore original bio completion handler */
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bio->bi_end_io = bip->bip_end_io;
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bio_endio_nodec(bio, error);
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}
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/**
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* bio_integrity_endio - Integrity I/O completion function
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* @bio: Protected bio
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* @error: Pointer to errno
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*
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* Description: Completion for integrity I/O
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*
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* Normally I/O completion is done in interrupt context. However,
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* verifying I/O integrity is a time-consuming task which must be run
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* in process context. This function postpones completion
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* accordingly.
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*/
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void bio_integrity_endio(struct bio *bio, int error)
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{
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struct bio_integrity_payload *bip = bio_integrity(bio);
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BUG_ON(bip->bip_bio != bio);
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/* In case of an I/O error there is no point in verifying the
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* integrity metadata. Restore original bio end_io handler
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* and run it.
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*/
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if (error) {
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bio->bi_end_io = bip->bip_end_io;
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bio_endio_nodec(bio, error);
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return;
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}
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INIT_WORK(&bip->bip_work, bio_integrity_verify_fn);
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queue_work(kintegrityd_wq, &bip->bip_work);
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}
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EXPORT_SYMBOL(bio_integrity_endio);
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/**
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* bio_integrity_advance - Advance integrity vector
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* @bio: bio whose integrity vector to update
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* @bytes_done: number of data bytes that have been completed
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*
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* Description: This function calculates how many integrity bytes the
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* number of completed data bytes correspond to and advances the
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* integrity vector accordingly.
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*/
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void bio_integrity_advance(struct bio *bio, unsigned int bytes_done)
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{
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struct bio_integrity_payload *bip = bio_integrity(bio);
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struct blk_integrity *bi = bdev_get_integrity(bio->bi_bdev);
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unsigned bytes = bio_integrity_bytes(bi, bytes_done >> 9);
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bvec_iter_advance(bip->bip_vec, &bip->bip_iter, bytes);
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}
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EXPORT_SYMBOL(bio_integrity_advance);
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/**
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* bio_integrity_trim - Trim integrity vector
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* @bio: bio whose integrity vector to update
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* @offset: offset to first data sector
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* @sectors: number of data sectors
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*
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* Description: Used to trim the integrity vector in a cloned bio.
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* The ivec will be advanced corresponding to 'offset' data sectors
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* and the length will be truncated corresponding to 'len' data
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* sectors.
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*/
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void bio_integrity_trim(struct bio *bio, unsigned int offset,
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unsigned int sectors)
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{
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struct bio_integrity_payload *bip = bio_integrity(bio);
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struct blk_integrity *bi = bdev_get_integrity(bio->bi_bdev);
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bio_integrity_advance(bio, offset << 9);
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bip->bip_iter.bi_size = bio_integrity_bytes(bi, sectors);
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}
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EXPORT_SYMBOL(bio_integrity_trim);
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/**
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* bio_integrity_clone - Callback for cloning bios with integrity metadata
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* @bio: New bio
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* @bio_src: Original bio
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* @gfp_mask: Memory allocation mask
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*
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* Description: Called to allocate a bip when cloning a bio
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*/
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int bio_integrity_clone(struct bio *bio, struct bio *bio_src,
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gfp_t gfp_mask)
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{
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struct bio_integrity_payload *bip_src = bio_integrity(bio_src);
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struct bio_integrity_payload *bip;
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BUG_ON(bip_src == NULL);
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bip = bio_integrity_alloc(bio, gfp_mask, bip_src->bip_vcnt);
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if (bip == NULL)
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return -EIO;
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memcpy(bip->bip_vec, bip_src->bip_vec,
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bip_src->bip_vcnt * sizeof(struct bio_vec));
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bip->bip_vcnt = bip_src->bip_vcnt;
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bip->bip_iter = bip_src->bip_iter;
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return 0;
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}
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EXPORT_SYMBOL(bio_integrity_clone);
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int bioset_integrity_create(struct bio_set *bs, int pool_size)
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{
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if (bs->bio_integrity_pool)
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return 0;
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bs->bio_integrity_pool = mempool_create_slab_pool(pool_size, bip_slab);
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if (!bs->bio_integrity_pool)
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return -1;
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bs->bvec_integrity_pool = biovec_create_pool(pool_size);
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if (!bs->bvec_integrity_pool) {
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mempool_destroy(bs->bio_integrity_pool);
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return -1;
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}
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return 0;
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}
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EXPORT_SYMBOL(bioset_integrity_create);
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void bioset_integrity_free(struct bio_set *bs)
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{
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if (bs->bio_integrity_pool)
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mempool_destroy(bs->bio_integrity_pool);
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if (bs->bvec_integrity_pool)
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mempool_destroy(bs->bvec_integrity_pool);
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}
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EXPORT_SYMBOL(bioset_integrity_free);
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void __init bio_integrity_init(void)
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{
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/*
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* kintegrityd won't block much but may burn a lot of CPU cycles.
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* Make it highpri CPU intensive wq with max concurrency of 1.
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*/
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kintegrityd_wq = alloc_workqueue("kintegrityd", WQ_MEM_RECLAIM |
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WQ_HIGHPRI | WQ_CPU_INTENSIVE, 1);
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if (!kintegrityd_wq)
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panic("Failed to create kintegrityd\n");
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bip_slab = kmem_cache_create("bio_integrity_payload",
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sizeof(struct bio_integrity_payload) +
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sizeof(struct bio_vec) * BIP_INLINE_VECS,
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0, SLAB_HWCACHE_ALIGN|SLAB_PANIC, NULL);
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if (!bip_slab)
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panic("Failed to create slab\n");
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}
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