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// SPDX-License-Identifier: GPL-2.0
/*
* Copyright (C) 2007, 2008, 2009 Oracle Corporation
* Written by: Martin K. Petersen <martin.petersen@oracle.com>
*
* Automatically generate and verify integrity data on PI capable devices if the
* bio submitter didn't provide PI itself. This ensures that kernel verifies
* data integrity even if the file system (or other user of the block device) is
* not aware of PI.
*/
#include <linux/blk-integrity.h>
#include <linux/workqueue.h>
#include "blk.h"
struct bio_integrity_data {
struct bio *bio;
struct bvec_iter saved_bio_iter;
struct work_struct work;
struct bio_integrity_payload bip;
struct bio_vec bvec;
};
static struct kmem_cache *bid_slab;
static mempool_t bid_pool;
static struct workqueue_struct *kintegrityd_wq;
static void bio_integrity_finish(struct bio_integrity_data *bid)
{
bid->bio->bi_integrity = NULL;
bid->bio->bi_opf &= ~REQ_INTEGRITY;
kfree(bvec_virt(bid->bip.bip_vec));
mempool_free(bid, &bid_pool);
}
static void bio_integrity_verify_fn(struct work_struct *work)
{
struct bio_integrity_data *bid =
container_of(work, struct bio_integrity_data, work);
struct bio *bio = bid->bio;
blk_integrity_verify_iter(bio, &bid->saved_bio_iter);
bio_integrity_finish(bid);
bio_endio(bio);
}
/**
* __bio_integrity_endio - Integrity I/O completion function
* @bio: Protected bio
*
* 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.
*/
bool __bio_integrity_endio(struct bio *bio)
{
struct blk_integrity *bi = blk_get_integrity(bio->bi_bdev->bd_disk);
struct bio_integrity_payload *bip = bio_integrity(bio);
struct bio_integrity_data *bid =
container_of(bip, struct bio_integrity_data, bip);
if (bio_op(bio) == REQ_OP_READ && !bio->bi_status && bi->csum_type) {
INIT_WORK(&bid->work, bio_integrity_verify_fn);
queue_work(kintegrityd_wq, &bid->work);
return false;
}
bio_integrity_finish(bid);
return true;
}
/**
* bio_integrity_prep - Prepare bio for integrity I/O
* @bio: bio to prepare
*
* Checks if the bio already has an integrity payload attached. If it does, the
* payload has been generated by another kernel subsystem, and we just pass it
* through.
* Otherwise allocates integrity payload and for writes the integrity metadata
* will be generated. For reads, the completion handler will verify the
* metadata.
*/
bool bio_integrity_prep(struct bio *bio)
{
struct blk_integrity *bi = blk_get_integrity(bio->bi_bdev->bd_disk);
struct bio_integrity_data *bid;
gfp_t gfp = GFP_NOIO;
unsigned int len;
void *buf;
if (!bi)
return true;
if (!bio_sectors(bio))
return true;
/* Already protected? */
if (bio_integrity(bio))
return true;
switch (bio_op(bio)) {
case REQ_OP_READ:
if (bi->flags & BLK_INTEGRITY_NOVERIFY)
return true;
break;
case REQ_OP_WRITE:
if (bi->flags & BLK_INTEGRITY_NOGENERATE)
return true;
/*
* Zero the memory allocated to not leak uninitialized kernel
* memory to disk for non-integrity metadata where nothing else
* initializes the memory.
*/
if (bi->csum_type == BLK_INTEGRITY_CSUM_NONE)
gfp |= __GFP_ZERO;
break;
default:
return true;
}
if (WARN_ON_ONCE(bio_has_crypt_ctx(bio)))
return true;
/* Allocate kernel buffer for protection data */
len = bio_integrity_bytes(bi, bio_sectors(bio));
buf = kmalloc(len, gfp);
if (!buf)
goto err_end_io;
bid = mempool_alloc(&bid_pool, GFP_NOIO);
if (!bid)
goto err_free_buf;
bio_integrity_init(bio, &bid->bip, &bid->bvec, 1);
bid->bio = bio;
bid->bip.bip_flags |= BIP_BLOCK_INTEGRITY;
bip_set_seed(&bid->bip, bio->bi_iter.bi_sector);
if (bi->csum_type == BLK_INTEGRITY_CSUM_IP)
bid->bip.bip_flags |= BIP_IP_CHECKSUM;
if (bi->csum_type)
bid->bip.bip_flags |= BIP_CHECK_GUARD;
if (bi->flags & BLK_INTEGRITY_REF_TAG)
bid->bip.bip_flags |= BIP_CHECK_REFTAG;
if (bio_integrity_add_page(bio, virt_to_page(buf), len,
offset_in_page(buf)) < len)
goto err_end_io;
/* Auto-generate integrity metadata if this is a write */
if (bio_data_dir(bio) == WRITE)
blk_integrity_generate(bio);
else
bid->saved_bio_iter = bio->bi_iter;
return true;
err_free_buf:
kfree(buf);
err_end_io:
bio->bi_status = BLK_STS_RESOURCE;
bio_endio(bio);
return false;
}
EXPORT_SYMBOL(bio_integrity_prep);
void blk_flush_integrity(void)
{
flush_workqueue(kintegrityd_wq);
}
static int __init blk_integrity_auto_init(void)
{
bid_slab = kmem_cache_create("bio_integrity_data",
sizeof(struct bio_integrity_data), 0,
SLAB_HWCACHE_ALIGN | SLAB_PANIC, NULL);
if (mempool_init_slab_pool(&bid_pool, BIO_POOL_SIZE, bid_slab))
panic("bio: can't create integrity pool\n");
/*
* 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");
return 0;
}
subsys_initcall(blk_integrity_auto_init);
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