block/bio-integrity.c - linux - Git at Google

 // 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 <martin.petersen@oracle.com>
  */

 #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);
 }

 static void __bio_integrity_free(struct bio_set *bs,
 				 struct bio_integrity_payload *bip)
 {
 	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_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));

 	if (nr_vecs > inline_vecs) {
 		bip->bip_max_vcnt = nr_vecs;
 		bip->bip_vec = bvec_alloc(&bs->bvec_integrity_pool,
 					  &bip->bip_max_vcnt, gfp_mask);
 		if (!bip->bip_vec)
 			goto err;
 	} 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:
 	__bio_integrity_free(bs, bip);
 	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(bvec_virt(bip->bip_vec));

 	__bio_integrity_free(bs, bip);
 	bio->bi_integrity = NULL;
 	bio->bi_opf &= ~REQ_INTEGRITY;
 }

 /**
  * 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_process - Process integrity metadata for a bio
  * @bio:	bio to generate/verify integrity metadata for
  * @proc_iter:  iterator to process
  * @proc_fn:	Pointer to the relevant processing function
  */
 static blk_status_t bio_integrity_process(struct bio *bio,
 		struct bvec_iter *proc_iter, integrity_processing_fn *proc_fn)
 {
 	struct blk_integrity *bi = blk_get_integrity(bio->bi_bdev->bd_disk);
 	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;

 	iter.disk_name = bio->bi_bdev->bd_disk->disk_name;
 	iter.interval = 1 << bi->interval_exp;
 	iter.tuple_size = bi->tuple_size;
 	iter.seed = proc_iter->bi_sector;
 	iter.prot_buf = bvec_virt(bip->bip_vec);

 	__bio_for_each_segment(bv, bio, bviter, *proc_iter) {
 		void *kaddr = bvec_kmap_local(&bv);

 		iter.data_buf = kaddr;
 		iter.data_size = bv.bv_len;
 		ret = proc_fn(&iter);
 		kunmap_local(kaddr);

 		if (ret)
 			break;

 	}
 	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);
 	void *buf;
 	unsigned long start, end;
 	unsigned int len, nr_pages;
 	unsigned int bytes, offset, i;
 	unsigned int intervals;
 	blk_status_t status;

 	if (!bi)
 		return true;

 	if (bio_op(bio) != REQ_OP_READ && bio_op(bio) != REQ_OP_WRITE)
 		return true;

 	if (!bio_sectors(bio))
 		return true;

 	/* Already protected? */
 	if (bio_integrity(bio))
 		return true;

 	if (bio_data_dir(bio) == READ) {
 		if (!bi->profile->verify_fn ||
 		    !(bi->flags & BLK_INTEGRITY_VERIFY))
 			return true;
 	} else {
 		if (!bi->profile->generate_fn ||
 		    !(bi->flags & BLK_INTEGRITY_GENERATE))
 			return true;
 	}
 	intervals = bio_integrity_intervals(bi, bio_sectors(bio));

 	/* Allocate kernel buffer for protection data */
 	len = intervals * bi->tuple_size;
 	buf = kmalloc(len, GFP_NOIO);
 	status = BLK_STS_RESOURCE;
 	if (unlikely(buf == NULL)) {
 		printk(KERN_ERR "could not allocate integrity buffer\n");
 		goto err_end_io;
 	}

 	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 (IS_ERR(bip)) {
 		printk(KERN_ERR "could not allocate data integrity bioset\n");
 		kfree(buf);
 		status = BLK_STS_RESOURCE;
 		goto err_end_io;
 	}

 	bip->bip_flags |= BIP_BLOCK_INTEGRITY;
 	bip->bip_iter.bi_size = len;
 	bip_set_seed(bip, bio->bi_iter.bi_sector);

 	if (bi->flags & BLK_INTEGRITY_IP_CHECKSUM)
 		bip->bip_flags |= BIP_IP_CHECKSUM;

 	/* 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) {
 			printk(KERN_ERR "could not attach integrity payload\n");
 			status = BLK_STS_RESOURCE;
 			goto err_end_io;
 		}

 		if (ret < bytes)
 			break;

 		buf += bytes;
 		len -= bytes;
 		offset = 0;
 	}

 	/* Auto-generate integrity metadata if this is a write */
 	if (bio_data_dir(bio) == WRITE) {
 		bio_integrity_process(bio, &bio->bi_iter,
 				      bi->profile->generate_fn);
 	} else {
 		bip->bio_iter = bio->bi_iter;
 	}
 	return true;

 err_end_io:
 	bio->bi_status = status;
 	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;
 	struct blk_integrity *bi = blk_get_integrity(bio->bi_bdev->bd_disk);

 	/*
 	 * At the moment verify is called bio's iterator was advanced
 	 * during split and completion, we need to rewind iterator to
 	 * it's original position.
 	 */
 	bio->bi_status = bio_integrity_process(bio, &bip->bio_iter,
 						bi->profile->verify_fn);
 	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 &&
 	    (bip->bip_flags & BIP_BLOCK_INTEGRITY) && bi->profile->verify_fn) {
 		INIT_WORK(&bip->bip_work, bio_integrity_verify_fn);
 		queue_work(kintegrityd_wq, &bip->bip_work);
 		return false;
 	}

 	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, bip_src->bip_vcnt);
 	if (IS_ERR(bip))
 		return PTR_ERR(bip);

 	memcpy(bip->bip_vec, bip_src->bip_vec,
 	       bip_src->bip_vcnt * sizeof(struct bio_vec));

 	bip->bip_vcnt = bip_src->bip_vcnt;
 	bip->bip_iter = bip_src->bip_iter;

 	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);
 }
	// 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 <martin.petersen@oracle.com>
	*/

	#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);
	}

	static void __bio_integrity_free(struct bio_set *bs,
	struct bio_integrity_payload *bip)
	{
	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_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));

	if (nr_vecs > inline_vecs) {
	bip->bip_max_vcnt = nr_vecs;
	bip->bip_vec = bvec_alloc(&bs->bvec_integrity_pool,
	&bip->bip_max_vcnt, gfp_mask);
	if (!bip->bip_vec)
	goto err;
	} 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:
	__bio_integrity_free(bs, bip);
	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(bvec_virt(bip->bip_vec));

	__bio_integrity_free(bs, bip);
	bio->bi_integrity = NULL;
	bio->bi_opf &= ~REQ_INTEGRITY;
	}

	/**
	* 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_process - Process integrity metadata for a bio
	* @bio: bio to generate/verify integrity metadata for
	* @proc_iter: iterator to process
	* @proc_fn: Pointer to the relevant processing function
	*/
	static blk_status_t bio_integrity_process(struct bio *bio,
	struct bvec_iter proc_iter, integrity_processing_fn proc_fn)
	{
	struct blk_integrity *bi = blk_get_integrity(bio->bi_bdev->bd_disk);
	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;

	iter.disk_name = bio->bi_bdev->bd_disk->disk_name;
	iter.interval = 1 << bi->interval_exp;
	iter.tuple_size = bi->tuple_size;
	iter.seed = proc_iter->bi_sector;
	iter.prot_buf = bvec_virt(bip->bip_vec);

	__bio_for_each_segment(bv, bio, bviter, *proc_iter) {
	void *kaddr = bvec_kmap_local(&bv);

	iter.data_buf = kaddr;
	iter.data_size = bv.bv_len;
	ret = proc_fn(&iter);
	kunmap_local(kaddr);

	if (ret)
	break;

	}
	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);
	void *buf;
	unsigned long start, end;
	unsigned int len, nr_pages;
	unsigned int bytes, offset, i;
	unsigned int intervals;
	blk_status_t status;

	if (!bi)
	return true;

	if (bio_op(bio) != REQ_OP_READ && bio_op(bio) != REQ_OP_WRITE)
	return true;

	if (!bio_sectors(bio))
	return true;

	/* Already protected? */
	if (bio_integrity(bio))
	return true;

	if (bio_data_dir(bio) == READ) {
	if (!bi->profile->verify_fn \|\|
	!(bi->flags & BLK_INTEGRITY_VERIFY))
	return true;
	} else {
	if (!bi->profile->generate_fn \|\|
	!(bi->flags & BLK_INTEGRITY_GENERATE))
	return true;
	}
	intervals = bio_integrity_intervals(bi, bio_sectors(bio));

	/* Allocate kernel buffer for protection data */
	len = intervals * bi->tuple_size;
	buf = kmalloc(len, GFP_NOIO);
	status = BLK_STS_RESOURCE;
	if (unlikely(buf == NULL)) {
	printk(KERN_ERR "could not allocate integrity buffer\n");
	goto err_end_io;
	}

	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 (IS_ERR(bip)) {
	printk(KERN_ERR "could not allocate data integrity bioset\n");
	kfree(buf);
	status = BLK_STS_RESOURCE;
	goto err_end_io;
	}

	bip->bip_flags \|= BIP_BLOCK_INTEGRITY;
	bip->bip_iter.bi_size = len;
	bip_set_seed(bip, bio->bi_iter.bi_sector);

	if (bi->flags & BLK_INTEGRITY_IP_CHECKSUM)
	bip->bip_flags \|= BIP_IP_CHECKSUM;

	/* 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) {
	printk(KERN_ERR "could not attach integrity payload\n");
	status = BLK_STS_RESOURCE;
	goto err_end_io;
	}

	if (ret < bytes)
	break;

	buf += bytes;
	len -= bytes;
	offset = 0;
	}

	/* Auto-generate integrity metadata if this is a write */
	if (bio_data_dir(bio) == WRITE) {
	bio_integrity_process(bio, &bio->bi_iter,
	bi->profile->generate_fn);
	} else {
	bip->bio_iter = bio->bi_iter;
	}
	return true;

	err_end_io:
	bio->bi_status = status;
	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;
	struct blk_integrity *bi = blk_get_integrity(bio->bi_bdev->bd_disk);

	/*
	* At the moment verify is called bio's iterator was advanced
	* during split and completion, we need to rewind iterator to
	* it's original position.
	*/
	bio->bi_status = bio_integrity_process(bio, &bip->bio_iter,
	bi->profile->verify_fn);
	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 &&
	(bip->bip_flags & BIP_BLOCK_INTEGRITY) && bi->profile->verify_fn) {
	INIT_WORK(&bip->bip_work, bio_integrity_verify_fn);
	queue_work(kintegrityd_wq, &bip->bip_work);
	return false;
	}

	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, bip_src->bip_vcnt);
	if (IS_ERR(bip))
	return PTR_ERR(bip);

	memcpy(bip->bip_vec, bip_src->bip_vec,
	bip_src->bip_vcnt * sizeof(struct bio_vec));

	bip->bip_vcnt = bip_src->bip_vcnt;
	bip->bip_iter = bip_src->bip_iter;

	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);
	}