// SPDX-License-Identifier: GPL-2.0
/*
* bio-integrity.c - bio data integrity extensions
*
* Copyright (C) 2007, 2008, 2009 Oracle Corporation
* Written by: Martin K. Petersen <[email protected]>
*/
#include <linux/blk-integrity.h>
#include <linux/mempool.h>
#include <linux/export.h>
#include <linux/bio.h>
#include <linux/workqueue.h>
#include <linux/slab.h>
#include "blk.h"
static struct kmem_cache *bip_slab;
static struct workqueue_struct *kintegrityd_wq;
void blk_flush_integrity(void)
{
flush_workqueue(kintegrityd_wq);
}
/**
* bio_integrity_free - Free bio integrity payload
* @bio: bio containing bip to be freed
*
* Description: Free the integrity portion of a bio.
*/
void bio_integrity_free(struct bio *bio)
{
struct bio_integrity_payload *bip = bio_integrity(bio);
struct bio_set *bs = bio->bi_pool;
if (bs && mempool_initialized(&bs->bio_integrity_pool)) {
if (bip->bip_vec)
bvec_free(&bs->bvec_integrity_pool, bip->bip_vec,
bip->bip_max_vcnt);
mempool_free(bip, &bs->bio_integrity_pool);
} else {
kfree(bip);
}
bio->bi_integrity = NULL;
bio->bi_opf &= ~REQ_INTEGRITY;
}
/**
* 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 (WARN_ON_ONCE(bio_has_crypt_ctx(bio)))
return ERR_PTR(-EOPNOTSUPP);
if (!bs || !mempool_initialized(&bs->bio_integrity_pool)) {
bip = kmalloc(struct_size(bip, bip_inline_vecs, nr_vecs), gfp_mask);
inline_vecs = nr_vecs;
} else {
bip = mempool_alloc(&bs->bio_integrity_pool, gfp_mask);
inline_vecs = BIO_INLINE_VECS;
}
if (unlikely(!bip))
return ERR_PTR(-ENOMEM);
memset(bip, 0, sizeof(*bip));
/* always report as many vecs as asked explicitly, not inline vecs */
bip->bip_max_vcnt = nr_vecs;
if (nr_vecs > inline_vecs) {
bip->bip_vec = bvec_alloc(&bs->bvec_integrity_pool,
&bip->bip_max_vcnt, gfp_mask);
if (!bip->bip_vec)
goto err;
} else if (nr_vecs) {
bip->bip_vec = bip->bip_inline_vecs;
}
bip->bip_bio = bio;
bio->bi_integrity = bip;
bio->bi_opf |= REQ_INTEGRITY;
return bip;
err:
if (bs && mempool_initialized(&bs->bio_integrity_pool))
mempool_free(bip, &bs->bio_integrity_pool);
else
kfree(bip);
return ERR_PTR(-ENOMEM);
}
EXPORT_SYMBOL(bio_integrity_alloc);
static void bio_integrity_unpin_bvec(struct bio_vec *bv, int nr_vecs,
bool dirty)
{
int i;
for (i = 0; i < nr_vecs; i++) {
if (dirty && !PageCompound(bv[i].bv_page))
set_page_dirty_lock(bv[i].bv_page);
unpin_user_page(bv[i].bv_page);
}
}
static void bio_integrity_uncopy_user(struct bio_integrity_payload *bip)
{
unsigned short nr_vecs = bip->bip_max_vcnt - 1;
struct bio_vec *copy = &bip->bip_vec[1];
size_t bytes = bip->bip_iter.bi_size;
struct iov_iter iter;
int ret;
iov_iter_bvec(&iter, ITER_DEST, copy, nr_vecs, bytes);
ret = copy_to_iter(bvec_virt(bip->bip_vec), bytes, &iter);
WARN_ON_ONCE(ret != bytes);
bio_integrity_unpin_bvec(copy, nr_vecs, true);
}
/**
* bio_integrity_unmap_user - Unmap user integrity payload
* @bio: bio containing bip to be unmapped
*
* Unmap the user mapped integrity portion of a bio.
*/
void bio_integrity_unmap_user(struct bio *bio)
{
struct bio_integrity_payload *bip = bio_integrity(bio);
if (bip->bip_flags & BIP_COPY_USER) {
if (bio_data_dir(bio) == READ)
bio_integrity_uncopy_user(bip);
kfree(bvec_virt(bip->bip_vec));
return;
}
bio_integrity_unpin_bvec(bip->bip_vec, bip->bip_max_vcnt,
bio_data_dir(bio) == READ);
}
/**
* 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 request_queue *q = bdev_get_queue(bio->bi_bdev);
struct bio_integrity_payload *bip = bio_integrity(bio);
if (bip->bip_vcnt > 0) {
struct bio_vec *bv = &bip->bip_vec[bip->bip_vcnt - 1];
bool same_page = false;
if (bvec_try_merge_hw_page(q, bv, page, len, offset,
&same_page)) {
bip->bip_iter.bi_size += len;
return len;
}
if (bip->bip_vcnt >=
min(bip->bip_max_vcnt, queue_max_integrity_segments(q)))
return 0;
/*
* If the queue doesn't support SG gaps and adding this segment
* would create a gap, disallow it.
*/
if (bvec_gap_to_prev(&q->limits, bv, offset))
return 0;
}
bvec_set_page(&bip->bip_vec[bip->bip_vcnt], page, len, offset);
bip->bip_vcnt++;
bip->bip_iter.bi_size += len;
return len;
}
EXPORT_SYMBOL(bio_integrity_add_page);
static int bio_integrity_copy_user(struct bio *bio, struct bio_vec *bvec,
int nr_vecs, unsigned int len,
unsigned int direction, u32 seed)
{
bool write = direction == ITER_SOURCE;
struct bio_integrity_payload *bip;
struct iov_iter iter;
void *buf;
int ret;
buf = kmalloc(len, GFP_KERNEL);
if (!buf)
return -ENOMEM;
if (write) {
iov_iter_bvec(&iter, direction, bvec, nr_vecs, len);
if (!copy_from_iter_full(buf, len, &iter)) {
ret = -EFAULT;
goto free_buf;
}
bip = bio_integrity_alloc(bio, GFP_KERNEL, 1);
} else {
memset(buf, 0, len);
/*
* We need to preserve the original bvec and the number of vecs
* in it for completion handling
*/
bip = bio_integrity_alloc(bio, GFP_KERNEL, nr_vecs + 1);
}
if (IS_ERR(bip)) {
ret = PTR_ERR(bip);
goto free_buf;
}
if (write)
bio_integrity_unpin_bvec(bvec, nr_vecs, false);
else
memcpy(&bip->bip_vec[1], bvec, nr_vecs * sizeof(*bvec));
ret = bio_integrity_add_page(bio, virt_to_page(buf), len,
offset_in_page(buf));
if (ret != len) {
ret = -ENOMEM;
goto free_bip;
}
bip->bip_flags |= BIP_COPY_USER;
bip->bip_iter.bi_sector = seed;
bip->bip_vcnt = nr_vecs;
return 0;
free_bip:
bio_integrity_free(bio);
free_buf:
kfree(buf);
return ret;
}
static int bio_integrity_init_user(struct bio *bio, struct bio_vec *bvec,
int nr_vecs, unsigned int len, u32 seed)
{
struct bio_integrity_payload *bip;
bip = bio_integrity_alloc(bio, GFP_KERNEL, nr_vecs);
if (IS_ERR(bip))
return PTR_ERR(bip);
memcpy(bip->bip_vec, bvec, nr_vecs * sizeof(*bvec));
bip->bip_iter.bi_sector = seed;
bip->bip_iter.bi_size = len;
bip->bip_vcnt = nr_vecs;
return 0;
}
static unsigned int bvec_from_pages(struct bio_vec *bvec, struct page **pages,
int nr_vecs, ssize_t bytes, ssize_t offset)
{
unsigned int nr_bvecs = 0;
int i, j;
for (i = 0; i < nr_vecs; i = j) {
size_t size = min_t(size_t, bytes, PAGE_SIZE - offset);
struct folio *folio = page_folio(pages[i]);
bytes -= size;
for (j = i + 1; j < nr_vecs; j++) {
size_t next = min_t(size_t, PAGE_SIZE, bytes);
if (page_folio(pages[j]) != folio ||
pages[j] != pages[j - 1] + 1)
break;
unpin_user_page(pages[j]);
size += next;
bytes -= next;
}
bvec_set_page(&bvec[nr_bvecs], pages[i], size, offset);
offset = 0;
nr_bvecs++;
}
return nr_bvecs;
}
int bio_integrity_map_user(struct bio *bio, void __user *ubuf, ssize_t bytes,
u32 seed)
{
struct request_queue *q = bdev_get_queue(bio->bi_bdev);
unsigned int align = blk_lim_dma_alignment_and_pad(&q->limits);
struct page *stack_pages[UIO_FASTIOV], **pages = stack_pages;
struct bio_vec stack_vec[UIO_FASTIOV], *bvec = stack_vec;
unsigned int direction, nr_bvecs;
struct iov_iter iter;
int ret, nr_vecs;
size_t offset;
bool copy;
if (bio_integrity(bio))
return -EINVAL;
if (bytes >> SECTOR_SHIFT > queue_max_hw_sectors(q))
return -E2BIG;
if (bio_data_dir(bio) == READ)
direction = ITER_DEST;
else
direction = ITER_SOURCE;
iov_iter_ubuf(&iter, direction, ubuf, bytes);
nr_vecs = iov_iter_npages(&iter, BIO_MAX_VECS + 1);
if (nr_vecs > BIO_MAX_VECS)
return -E2BIG;
if (nr_vecs > UIO_FASTIOV) {
bvec = kcalloc(nr_vecs, sizeof(*bvec), GFP_KERNEL);
if (!bvec)
return -ENOMEM;
pages = NULL;
}
copy = !iov_iter_is_aligned(&iter, align, align);
ret = iov_iter_extract_pages(&iter, &pages, bytes, nr_vecs, 0, &offset);
if (unlikely(ret < 0))
goto free_bvec;
nr_bvecs = bvec_from_pages(bvec, pages, nr_vecs, bytes, offset);
if (pages != stack_pages)
kvfree(pages);
if (nr_bvecs > queue_max_integrity_segments(q))
copy = true;
if (copy)
ret = bio_integrity_copy_user(bio, bvec, nr_bvecs, bytes,
direction, seed);
else
ret = bio_integrity_init_user(bio, bvec, nr_bvecs, bytes, seed);
if (ret)
goto release_pages;
if (bvec != stack_vec)
kfree(bvec);
return 0;
release_pages:
bio_integrity_unpin_bvec(bvec, nr_bvecs, false);
free_bvec:
if (bvec != stack_vec)
kfree(bvec);
return ret;
}
/**
* bio_integrity_prep - Prepare bio for integrity I/O
* @bio: bio to prepare
*
* Description: 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.
* 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.
*/
bool bio_integrity_prep(struct bio *bio)
{
struct bio_integrity_payload *bip;
struct blk_integrity *bi = blk_get_integrity(bio->bi_bdev->bd_disk);
unsigned int len;
void *buf;
gfp_t gfp = GFP_NOIO;
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;
}
/* Allocate kernel buffer for protection data */
len = bio_integrity_bytes(bi, bio_sectors(bio));
buf = kmalloc(len, gfp);
if (unlikely(buf == NULL)) {
goto err_end_io;
}
bip = bio_integrity_alloc(bio, GFP_NOIO, 1);
if (IS_ERR(bip)) {
kfree(buf);
goto err_end_io;
}
bip->bip_flags |= BIP_BLOCK_INTEGRITY;
bip_set_seed(bip, bio->bi_iter.bi_sector);
if (bi->csum_type == BLK_INTEGRITY_CSUM_IP)
bip->bip_flags |= BIP_IP_CHECKSUM;
if (bio_integrity_add_page(bio, virt_to_page(buf), len,
offset_in_page(buf)) < len) {
printk(KERN_ERR "could not attach integrity payload\n");
goto err_end_io;
}
/* Auto-generate integrity metadata if this is a write */
if (bio_data_dir(bio) == WRITE)
blk_integrity_generate(bio);
else
bip->bio_iter = bio->bi_iter;
return true;
err_end_io:
bio->bi_status = BLK_STS_RESOURCE;
bio_endio(bio);
return false;
}
EXPORT_SYMBOL(bio_integrity_prep);
/**
* 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;
blk_integrity_verify(bio);
kfree(bvec_virt(bip->bip_vec));
bio_integrity_free(bio);
bio_endio(bio);
}
/**
* __bio_integrity_endio - Integrity I/O completion function
* @bio: Protected bio
*
* 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.
*/
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);
if (bio_op(bio) == REQ_OP_READ && !bio->bi_status && bi->csum_type) {
INIT_WORK(&bip->bip_work, bio_integrity_verify_fn);
queue_work(kintegrityd_wq, &bip->bip_work);
return false;
}
kfree(bvec_virt(bip->bip_vec));
bio_integrity_free(bio);
return true;
}
/**
* 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_integrity(bio);
struct blk_integrity *bi = blk_get_integrity(bio->bi_bdev->bd_disk);
unsigned bytes = bio_integrity_bytes(bi, bytes_done >> 9);
bip->bip_iter.bi_sector += bio_integrity_intervals(bi, bytes_done >> 9);
bvec_iter_advance(bip->bip_vec, &bip->bip_iter, bytes);
}
/**
* bio_integrity_trim - Trim integrity vector
* @bio: bio whose integrity vector to update
*
* Description: Used to trim the integrity vector in a cloned bio.
*/
void bio_integrity_trim(struct bio *bio)
{
struct bio_integrity_payload *bip = bio_integrity(bio);
struct blk_integrity *bi = blk_get_integrity(bio->bi_bdev->bd_disk);
bip->bip_iter.bi_size = bio_integrity_bytes(bi, bio_sectors(bio));
}
EXPORT_SYMBOL(bio_integrity_trim);
/**
* 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_integrity(bio_src);
struct bio_integrity_payload *bip;
BUG_ON(bip_src == NULL);
bip = bio_integrity_alloc(bio, gfp_mask, 0);
if (IS_ERR(bip))
return PTR_ERR(bip);
bip->bip_vec = bip_src->bip_vec;
bip->bip_iter = bip_src->bip_iter;
bip->bip_flags = bip_src->bip_flags & ~BIP_BLOCK_INTEGRITY;
return 0;
}
int bioset_integrity_create(struct bio_set *bs, int pool_size)
{
if (mempool_initialized(&bs->bio_integrity_pool))
return 0;
if (mempool_init_slab_pool(&bs->bio_integrity_pool,
pool_size, bip_slab))
return -1;
if (biovec_init_pool(&bs->bvec_integrity_pool, pool_size)) {
mempool_exit(&bs->bio_integrity_pool);
return -1;
}
return 0;
}
EXPORT_SYMBOL(bioset_integrity_create);
void bioset_integrity_free(struct bio_set *bs)
{
mempool_exit(&bs->bio_integrity_pool);
mempool_exit(&bs->bvec_integrity_pool);
}
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) * BIO_INLINE_VECS,
0, SLAB_HWCACHE_ALIGN|SLAB_PANIC, NULL);
}
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