drivers/nvme/target/io-cmd-bdev.c - third_party/linux - Git at Google

 // SPDX-License-Identifier: GPL-2.0
 /*
  * NVMe I/O command implementation.
  * Copyright (c) 2015-2016 HGST, a Western Digital Company.
  */
 #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
 #include <linux/blkdev.h>
 #include <linux/blk-integrity.h>
 #include <linux/memremap.h>
 #include <linux/module.h>
 #include "nvmet.h"

 void nvmet_bdev_set_limits(struct block_device *bdev, struct nvme_id_ns *id)
 {
 	const struct queue_limits *ql = &bdev_get_queue(bdev)->limits;
 	/* Number of logical blocks per physical block. */
 	const u32 lpp = ql->physical_block_size / ql->logical_block_size;
 	/* Logical blocks per physical block, 0's based. */
 	const __le16 lpp0b = to0based(lpp);

 	/*
 	 * For NVMe 1.2 and later, bit 1 indicates that the fields NAWUN,
 	 * NAWUPF, and NACWU are defined for this namespace and should be
 	 * used by the host for this namespace instead of the AWUN, AWUPF,
 	 * and ACWU fields in the Identify Controller data structure. If
 	 * any of these fields are zero that means that the corresponding
 	 * field from the identify controller data structure should be used.
 	 */
 	id->nsfeat |= 1 << 1;
 	id->nawun = lpp0b;
 	id->nawupf = lpp0b;
 	id->nacwu = lpp0b;

 	/*
 	 * Bit 4 indicates that the fields NPWG, NPWA, NPDG, NPDA, and
 	 * NOWS are defined for this namespace and should be used by
 	 * the host for I/O optimization.
 	 */
 	id->nsfeat |= 1 << 4;
 	/* NPWG = Namespace Preferred Write Granularity. 0's based */
 	id->npwg = lpp0b;
 	/* NPWA = Namespace Preferred Write Alignment. 0's based */
 	id->npwa = id->npwg;
 	/* NPDG = Namespace Preferred Deallocate Granularity. 0's based */
 	id->npdg = to0based(ql->discard_granularity / ql->logical_block_size);
 	/* NPDG = Namespace Preferred Deallocate Alignment */
 	id->npda = id->npdg;
 	/* NOWS = Namespace Optimal Write Size */
 	id->nows = to0based(ql->io_opt / ql->logical_block_size);
 }

 void nvmet_bdev_ns_disable(struct nvmet_ns *ns)
 {
 	if (ns->bdev) {
 		blkdev_put(ns->bdev, FMODE_WRITE | FMODE_READ);
 		ns->bdev = NULL;
 	}
 }

 static void nvmet_bdev_ns_enable_integrity(struct nvmet_ns *ns)
 {
 	struct blk_integrity *bi = bdev_get_integrity(ns->bdev);

 	if (bi) {
 		ns->metadata_size = bi->tuple_size;
 		if (bi->profile == &t10_pi_type1_crc)
 			ns->pi_type = NVME_NS_DPS_PI_TYPE1;
 		else if (bi->profile == &t10_pi_type3_crc)
 			ns->pi_type = NVME_NS_DPS_PI_TYPE3;
 		else
 			/* Unsupported metadata type */
 			ns->metadata_size = 0;
 	}
 }

 int nvmet_bdev_ns_enable(struct nvmet_ns *ns)
 {
 	int ret;

 	/*
 	 * When buffered_io namespace attribute is enabled that means user want
 	 * this block device to be used as a file, so block device can take
 	 * an advantage of cache.
 	 */
 	if (ns->buffered_io)
 		return -ENOTBLK;

 	ns->bdev = blkdev_get_by_path(ns->device_path,
 			FMODE_READ | FMODE_WRITE, NULL);
 	if (IS_ERR(ns->bdev)) {
 		ret = PTR_ERR(ns->bdev);
 		if (ret != -ENOTBLK) {
 			pr_err("failed to open block device %s: (%ld)\n",
 					ns->device_path, PTR_ERR(ns->bdev));
 		}
 		ns->bdev = NULL;
 		return ret;
 	}
 	ns->size = bdev_nr_bytes(ns->bdev);
 	ns->blksize_shift = blksize_bits(bdev_logical_block_size(ns->bdev));

 	ns->pi_type = 0;
 	ns->metadata_size = 0;
 	if (IS_ENABLED(CONFIG_BLK_DEV_INTEGRITY_T10))
 		nvmet_bdev_ns_enable_integrity(ns);

 	if (bdev_is_zoned(ns->bdev)) {
 		if (!nvmet_bdev_zns_enable(ns)) {
 			nvmet_bdev_ns_disable(ns);
 			return -EINVAL;
 		}
 		ns->csi = NVME_CSI_ZNS;
 	}

 	return 0;
 }

 void nvmet_bdev_ns_revalidate(struct nvmet_ns *ns)
 {
 	ns->size = bdev_nr_bytes(ns->bdev);
 }

 u16 blk_to_nvme_status(struct nvmet_req *req, blk_status_t blk_sts)
 {
 	u16 status = NVME_SC_SUCCESS;

 	if (likely(blk_sts == BLK_STS_OK))
 		return status;
 	/*
 	 * Right now there exists M : 1 mapping between block layer error
 	 * to the NVMe status code (see nvme_error_status()). For consistency,
 	 * when we reverse map we use most appropriate NVMe Status code from
 	 * the group of the NVMe staus codes used in the nvme_error_status().
 	 */
 	switch (blk_sts) {
 	case BLK_STS_NOSPC:
 		status = NVME_SC_CAP_EXCEEDED | NVME_SC_DNR;
 		req->error_loc = offsetof(struct nvme_rw_command, length);
 		break;
 	case BLK_STS_TARGET:
 		status = NVME_SC_LBA_RANGE | NVME_SC_DNR;
 		req->error_loc = offsetof(struct nvme_rw_command, slba);
 		break;
 	case BLK_STS_NOTSUPP:
 		req->error_loc = offsetof(struct nvme_common_command, opcode);
 		switch (req->cmd->common.opcode) {
 		case nvme_cmd_dsm:
 		case nvme_cmd_write_zeroes:
 			status = NVME_SC_ONCS_NOT_SUPPORTED | NVME_SC_DNR;
 			break;
 		default:
 			status = NVME_SC_INVALID_OPCODE | NVME_SC_DNR;
 		}
 		break;
 	case BLK_STS_MEDIUM:
 		status = NVME_SC_ACCESS_DENIED;
 		req->error_loc = offsetof(struct nvme_rw_command, nsid);
 		break;
 	case BLK_STS_IOERR:
 	default:
 		status = NVME_SC_INTERNAL | NVME_SC_DNR;
 		req->error_loc = offsetof(struct nvme_common_command, opcode);
 	}

 	switch (req->cmd->common.opcode) {
 	case nvme_cmd_read:
 	case nvme_cmd_write:
 		req->error_slba = le64_to_cpu(req->cmd->rw.slba);
 		break;
 	case nvme_cmd_write_zeroes:
 		req->error_slba =
 			le64_to_cpu(req->cmd->write_zeroes.slba);
 		break;
 	default:
 		req->error_slba = 0;
 	}
 	return status;
 }

 static void nvmet_bio_done(struct bio *bio)
 {
 	struct nvmet_req *req = bio->bi_private;

 	nvmet_req_complete(req, blk_to_nvme_status(req, bio->bi_status));
 	nvmet_req_bio_put(req, bio);
 }

 #ifdef CONFIG_BLK_DEV_INTEGRITY
 static int nvmet_bdev_alloc_bip(struct nvmet_req *req, struct bio *bio,
 				struct sg_mapping_iter *miter)
 {
 	struct blk_integrity *bi;
 	struct bio_integrity_payload *bip;
 	int rc;
 	size_t resid, len;

 	bi = bdev_get_integrity(req->ns->bdev);
 	if (unlikely(!bi)) {
 		pr_err("Unable to locate bio_integrity\n");
 		return -ENODEV;
 	}

 	bip = bio_integrity_alloc(bio, GFP_NOIO,
 					bio_max_segs(req->metadata_sg_cnt));
 	if (IS_ERR(bip)) {
 		pr_err("Unable to allocate bio_integrity_payload\n");
 		return PTR_ERR(bip);
 	}

 	bip->bip_iter.bi_size = bio_integrity_bytes(bi, bio_sectors(bio));
 	/* virtual start sector must be in integrity interval units */
 	bip_set_seed(bip, bio->bi_iter.bi_sector >>
 		     (bi->interval_exp - SECTOR_SHIFT));

 	resid = bip->bip_iter.bi_size;
 	while (resid > 0 && sg_miter_next(miter)) {
 		len = min_t(size_t, miter->length, resid);
 		rc = bio_integrity_add_page(bio, miter->page, len,
 					    offset_in_page(miter->addr));
 		if (unlikely(rc != len)) {
 			pr_err("bio_integrity_add_page() failed; %d\n", rc);
 			sg_miter_stop(miter);
 			return -ENOMEM;
 		}

 		resid -= len;
 		if (len < miter->length)
 			miter->consumed -= miter->length - len;
 	}
 	sg_miter_stop(miter);

 	return 0;
 }
 #else
 static int nvmet_bdev_alloc_bip(struct nvmet_req *req, struct bio *bio,
 				struct sg_mapping_iter *miter)
 {
 	return -EINVAL;
 }
 #endif /* CONFIG_BLK_DEV_INTEGRITY */

 static void nvmet_bdev_execute_rw(struct nvmet_req *req)
 {
 	unsigned int sg_cnt = req->sg_cnt;
 	struct bio *bio;
 	struct scatterlist *sg;
 	struct blk_plug plug;
 	sector_t sector;
 	blk_opf_t opf;
 	int i, rc;
 	struct sg_mapping_iter prot_miter;
 	unsigned int iter_flags;
 	unsigned int total_len = nvmet_rw_data_len(req) + req->metadata_len;

 	if (!nvmet_check_transfer_len(req, total_len))
 		return;

 	if (!req->sg_cnt) {
 		nvmet_req_complete(req, 0);
 		return;
 	}

 	if (req->cmd->rw.opcode == nvme_cmd_write) {
 		opf = REQ_OP_WRITE | REQ_SYNC | REQ_IDLE;
 		if (req->cmd->rw.control & cpu_to_le16(NVME_RW_FUA))
 			opf |= REQ_FUA;
 		iter_flags = SG_MITER_TO_SG;
 	} else {
 		opf = REQ_OP_READ;
 		iter_flags = SG_MITER_FROM_SG;
 	}

 	if (is_pci_p2pdma_page(sg_page(req->sg)))
 		opf |= REQ_NOMERGE;

 	sector = nvmet_lba_to_sect(req->ns, req->cmd->rw.slba);

 	if (nvmet_use_inline_bvec(req)) {
 		bio = &req->b.inline_bio;
 		bio_init(bio, req->ns->bdev, req->inline_bvec,
 			 ARRAY_SIZE(req->inline_bvec), opf);
 	} else {
 		bio = bio_alloc(req->ns->bdev, bio_max_segs(sg_cnt), opf,
 				GFP_KERNEL);
 	}
 	bio->bi_iter.bi_sector = sector;
 	bio->bi_private = req;
 	bio->bi_end_io = nvmet_bio_done;

 	blk_start_plug(&plug);
 	if (req->metadata_len)
 		sg_miter_start(&prot_miter, req->metadata_sg,
 			       req->metadata_sg_cnt, iter_flags);

 	for_each_sg(req->sg, sg, req->sg_cnt, i) {
 		while (bio_add_page(bio, sg_page(sg), sg->length, sg->offset)
 				!= sg->length) {
 			struct bio *prev = bio;

 			if (req->metadata_len) {
 				rc = nvmet_bdev_alloc_bip(req, bio,
 							  &prot_miter);
 				if (unlikely(rc)) {
 					bio_io_error(bio);
 					return;
 				}
 			}

 			bio = bio_alloc(req->ns->bdev, bio_max_segs(sg_cnt),
 					opf, GFP_KERNEL);
 			bio->bi_iter.bi_sector = sector;

 			bio_chain(bio, prev);
 			submit_bio(prev);
 		}

 		sector += sg->length >> 9;
 		sg_cnt--;
 	}

 	if (req->metadata_len) {
 		rc = nvmet_bdev_alloc_bip(req, bio, &prot_miter);
 		if (unlikely(rc)) {
 			bio_io_error(bio);
 			return;
 		}
 	}

 	submit_bio(bio);
 	blk_finish_plug(&plug);
 }

 static void nvmet_bdev_execute_flush(struct nvmet_req *req)
 {
 	struct bio *bio = &req->b.inline_bio;

 	if (!nvmet_check_transfer_len(req, 0))
 		return;

 	bio_init(bio, req->ns->bdev, req->inline_bvec,
 		 ARRAY_SIZE(req->inline_bvec), REQ_OP_WRITE | REQ_PREFLUSH);
 	bio->bi_private = req;
 	bio->bi_end_io = nvmet_bio_done;

 	submit_bio(bio);
 }

 u16 nvmet_bdev_flush(struct nvmet_req *req)
 {
 	if (blkdev_issue_flush(req->ns->bdev))
 		return NVME_SC_INTERNAL | NVME_SC_DNR;
 	return 0;
 }

 static u16 nvmet_bdev_discard_range(struct nvmet_req *req,
 		struct nvme_dsm_range *range, struct bio **bio)
 {
 	struct nvmet_ns *ns = req->ns;
 	int ret;

 	ret = __blkdev_issue_discard(ns->bdev,
 			nvmet_lba_to_sect(ns, range->slba),
 			le32_to_cpu(range->nlb) << (ns->blksize_shift - 9),
 			GFP_KERNEL, bio);
 	if (ret && ret != -EOPNOTSUPP) {
 		req->error_slba = le64_to_cpu(range->slba);
 		return errno_to_nvme_status(req, ret);
 	}
 	return NVME_SC_SUCCESS;
 }

 static void nvmet_bdev_execute_discard(struct nvmet_req *req)
 {
 	struct nvme_dsm_range range;
 	struct bio *bio = NULL;
 	int i;
 	u16 status;

 	for (i = 0; i <= le32_to_cpu(req->cmd->dsm.nr); i++) {
 		status = nvmet_copy_from_sgl(req, i * sizeof(range), &range,
 				sizeof(range));
 		if (status)
 			break;

 		status = nvmet_bdev_discard_range(req, &range, &bio);
 		if (status)
 			break;
 	}

 	if (bio) {
 		bio->bi_private = req;
 		bio->bi_end_io = nvmet_bio_done;
 		if (status)
 			bio_io_error(bio);
 		else
 			submit_bio(bio);
 	} else {
 		nvmet_req_complete(req, status);
 	}
 }

 static void nvmet_bdev_execute_dsm(struct nvmet_req *req)
 {
 	if (!nvmet_check_data_len_lte(req, nvmet_dsm_len(req)))
 		return;

 	switch (le32_to_cpu(req->cmd->dsm.attributes)) {
 	case NVME_DSMGMT_AD:
 		nvmet_bdev_execute_discard(req);
 		return;
 	case NVME_DSMGMT_IDR:
 	case NVME_DSMGMT_IDW:
 	default:
 		/* Not supported yet */
 		nvmet_req_complete(req, 0);
 		return;
 	}
 }

 static void nvmet_bdev_execute_write_zeroes(struct nvmet_req *req)
 {
 	struct nvme_write_zeroes_cmd *write_zeroes = &req->cmd->write_zeroes;
 	struct bio *bio = NULL;
 	sector_t sector;
 	sector_t nr_sector;
 	int ret;

 	if (!nvmet_check_transfer_len(req, 0))
 		return;

 	sector = nvmet_lba_to_sect(req->ns, write_zeroes->slba);
 	nr_sector = (((sector_t)le16_to_cpu(write_zeroes->length) + 1) <<
 		(req->ns->blksize_shift - 9));

 	ret = __blkdev_issue_zeroout(req->ns->bdev, sector, nr_sector,
 			GFP_KERNEL, &bio, 0);
 	if (bio) {
 		bio->bi_private = req;
 		bio->bi_end_io = nvmet_bio_done;
 		submit_bio(bio);
 	} else {
 		nvmet_req_complete(req, errno_to_nvme_status(req, ret));
 	}
 }

 u16 nvmet_bdev_parse_io_cmd(struct nvmet_req *req)
 {
 	switch (req->cmd->common.opcode) {
 	case nvme_cmd_read:
 	case nvme_cmd_write:
 		req->execute = nvmet_bdev_execute_rw;
 		if (req->sq->ctrl->pi_support && nvmet_ns_has_pi(req->ns))
 			req->metadata_len = nvmet_rw_metadata_len(req);
 		return 0;
 	case nvme_cmd_flush:
 		req->execute = nvmet_bdev_execute_flush;
 		return 0;
 	case nvme_cmd_dsm:
 		req->execute = nvmet_bdev_execute_dsm;
 		return 0;
 	case nvme_cmd_write_zeroes:
 		req->execute = nvmet_bdev_execute_write_zeroes;
 		return 0;
 	default:
 		return nvmet_report_invalid_opcode(req);
 	}
 }
	// SPDX-License-Identifier: GPL-2.0
	/*
	* NVMe I/O command implementation.
	* Copyright (c) 2015-2016 HGST, a Western Digital Company.
	*/
	#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
	#include <linux/blkdev.h>
	#include <linux/blk-integrity.h>
	#include <linux/memremap.h>
	#include <linux/module.h>
	#include "nvmet.h"

	void nvmet_bdev_set_limits(struct block_device bdev, struct nvme_id_ns id)
	{
	const struct queue_limits *ql = &bdev_get_queue(bdev)->limits;
	/* Number of logical blocks per physical block. */
	const u32 lpp = ql->physical_block_size / ql->logical_block_size;
	/* Logical blocks per physical block, 0's based. */
	const __le16 lpp0b = to0based(lpp);

	/*
	* For NVMe 1.2 and later, bit 1 indicates that the fields NAWUN,
	* NAWUPF, and NACWU are defined for this namespace and should be
	* used by the host for this namespace instead of the AWUN, AWUPF,
	* and ACWU fields in the Identify Controller data structure. If
	* any of these fields are zero that means that the corresponding
	* field from the identify controller data structure should be used.
	*/
	id->nsfeat \|= 1 << 1;
	id->nawun = lpp0b;
	id->nawupf = lpp0b;
	id->nacwu = lpp0b;

	/*
	* Bit 4 indicates that the fields NPWG, NPWA, NPDG, NPDA, and
	* NOWS are defined for this namespace and should be used by
	* the host for I/O optimization.
	*/
	id->nsfeat \|= 1 << 4;
	/* NPWG = Namespace Preferred Write Granularity. 0's based */
	id->npwg = lpp0b;
	/* NPWA = Namespace Preferred Write Alignment. 0's based */
	id->npwa = id->npwg;
	/* NPDG = Namespace Preferred Deallocate Granularity. 0's based */
	id->npdg = to0based(ql->discard_granularity / ql->logical_block_size);
	/* NPDG = Namespace Preferred Deallocate Alignment */
	id->npda = id->npdg;
	/* NOWS = Namespace Optimal Write Size */
	id->nows = to0based(ql->io_opt / ql->logical_block_size);
	}

	void nvmet_bdev_ns_disable(struct nvmet_ns *ns)
	{
	if (ns->bdev) {
	blkdev_put(ns->bdev, FMODE_WRITE \| FMODE_READ);
	ns->bdev = NULL;
	}
	}

	static void nvmet_bdev_ns_enable_integrity(struct nvmet_ns *ns)
	{
	struct blk_integrity *bi = bdev_get_integrity(ns->bdev);

	if (bi) {
	ns->metadata_size = bi->tuple_size;
	if (bi->profile == &t10_pi_type1_crc)
	ns->pi_type = NVME_NS_DPS_PI_TYPE1;
	else if (bi->profile == &t10_pi_type3_crc)
	ns->pi_type = NVME_NS_DPS_PI_TYPE3;
	else
	/* Unsupported metadata type */
	ns->metadata_size = 0;
	}
	}

	int nvmet_bdev_ns_enable(struct nvmet_ns *ns)
	{
	int ret;

	/*
	* When buffered_io namespace attribute is enabled that means user want
	* this block device to be used as a file, so block device can take
	* an advantage of cache.
	*/
	if (ns->buffered_io)
	return -ENOTBLK;

	ns->bdev = blkdev_get_by_path(ns->device_path,
	FMODE_READ \| FMODE_WRITE, NULL);
	if (IS_ERR(ns->bdev)) {
	ret = PTR_ERR(ns->bdev);
	if (ret != -ENOTBLK) {
	pr_err("failed to open block device %s: (%ld)\n",
	ns->device_path, PTR_ERR(ns->bdev));
	}
	ns->bdev = NULL;
	return ret;
	}
	ns->size = bdev_nr_bytes(ns->bdev);
	ns->blksize_shift = blksize_bits(bdev_logical_block_size(ns->bdev));

	ns->pi_type = 0;
	ns->metadata_size = 0;
	if (IS_ENABLED(CONFIG_BLK_DEV_INTEGRITY_T10))
	nvmet_bdev_ns_enable_integrity(ns);

	if (bdev_is_zoned(ns->bdev)) {
	if (!nvmet_bdev_zns_enable(ns)) {
	nvmet_bdev_ns_disable(ns);
	return -EINVAL;
	}
	ns->csi = NVME_CSI_ZNS;
	}

	return 0;
	}

	void nvmet_bdev_ns_revalidate(struct nvmet_ns *ns)
	{
	ns->size = bdev_nr_bytes(ns->bdev);
	}

	u16 blk_to_nvme_status(struct nvmet_req *req, blk_status_t blk_sts)
	{
	u16 status = NVME_SC_SUCCESS;

	if (likely(blk_sts == BLK_STS_OK))
	return status;
	/*
	* Right now there exists M : 1 mapping between block layer error
	* to the NVMe status code (see nvme_error_status()). For consistency,
	* when we reverse map we use most appropriate NVMe Status code from
	* the group of the NVMe staus codes used in the nvme_error_status().
	*/
	switch (blk_sts) {
	case BLK_STS_NOSPC:
	status = NVME_SC_CAP_EXCEEDED \| NVME_SC_DNR;
	req->error_loc = offsetof(struct nvme_rw_command, length);
	break;
	case BLK_STS_TARGET:
	status = NVME_SC_LBA_RANGE \| NVME_SC_DNR;
	req->error_loc = offsetof(struct nvme_rw_command, slba);
	break;
	case BLK_STS_NOTSUPP:
	req->error_loc = offsetof(struct nvme_common_command, opcode);
	switch (req->cmd->common.opcode) {
	case nvme_cmd_dsm:
	case nvme_cmd_write_zeroes:
	status = NVME_SC_ONCS_NOT_SUPPORTED \| NVME_SC_DNR;
	break;
	default:
	status = NVME_SC_INVALID_OPCODE \| NVME_SC_DNR;
	}
	break;
	case BLK_STS_MEDIUM:
	status = NVME_SC_ACCESS_DENIED;
	req->error_loc = offsetof(struct nvme_rw_command, nsid);
	break;
	case BLK_STS_IOERR:
	default:
	status = NVME_SC_INTERNAL \| NVME_SC_DNR;
	req->error_loc = offsetof(struct nvme_common_command, opcode);
	}

	switch (req->cmd->common.opcode) {
	case nvme_cmd_read:
	case nvme_cmd_write:
	req->error_slba = le64_to_cpu(req->cmd->rw.slba);
	break;
	case nvme_cmd_write_zeroes:
	req->error_slba =
	le64_to_cpu(req->cmd->write_zeroes.slba);
	break;
	default:
	req->error_slba = 0;
	}
	return status;
	}

	static void nvmet_bio_done(struct bio *bio)
	{
	struct nvmet_req *req = bio->bi_private;

	nvmet_req_complete(req, blk_to_nvme_status(req, bio->bi_status));
	nvmet_req_bio_put(req, bio);
	}

	#ifdef CONFIG_BLK_DEV_INTEGRITY
	static int nvmet_bdev_alloc_bip(struct nvmet_req req, struct bio bio,
	struct sg_mapping_iter *miter)
	{
	struct blk_integrity *bi;
	struct bio_integrity_payload *bip;
	int rc;
	size_t resid, len;

	bi = bdev_get_integrity(req->ns->bdev);
	if (unlikely(!bi)) {
	pr_err("Unable to locate bio_integrity\n");
	return -ENODEV;
	}

	bip = bio_integrity_alloc(bio, GFP_NOIO,
	bio_max_segs(req->metadata_sg_cnt));
	if (IS_ERR(bip)) {
	pr_err("Unable to allocate bio_integrity_payload\n");
	return PTR_ERR(bip);
	}

	bip->bip_iter.bi_size = bio_integrity_bytes(bi, bio_sectors(bio));
	/* virtual start sector must be in integrity interval units */
	bip_set_seed(bip, bio->bi_iter.bi_sector >>
	(bi->interval_exp - SECTOR_SHIFT));

	resid = bip->bip_iter.bi_size;
	while (resid > 0 && sg_miter_next(miter)) {
	len = min_t(size_t, miter->length, resid);
	rc = bio_integrity_add_page(bio, miter->page, len,
	offset_in_page(miter->addr));
	if (unlikely(rc != len)) {
	pr_err("bio_integrity_add_page() failed; %d\n", rc);
	sg_miter_stop(miter);
	return -ENOMEM;
	}

	resid -= len;
	if (len < miter->length)
	miter->consumed -= miter->length - len;
	}
	sg_miter_stop(miter);

	return 0;
	}
	#else
	static int nvmet_bdev_alloc_bip(struct nvmet_req req, struct bio bio,
	struct sg_mapping_iter *miter)
	{
	return -EINVAL;
	}
	#endif /* CONFIG_BLK_DEV_INTEGRITY */

	static void nvmet_bdev_execute_rw(struct nvmet_req *req)
	{
	unsigned int sg_cnt = req->sg_cnt;
	struct bio *bio;
	struct scatterlist *sg;
	struct blk_plug plug;
	sector_t sector;
	blk_opf_t opf;
	int i, rc;
	struct sg_mapping_iter prot_miter;
	unsigned int iter_flags;
	unsigned int total_len = nvmet_rw_data_len(req) + req->metadata_len;

	if (!nvmet_check_transfer_len(req, total_len))
	return;

	if (!req->sg_cnt) {
	nvmet_req_complete(req, 0);
	return;
	}

	if (req->cmd->rw.opcode == nvme_cmd_write) {
	opf = REQ_OP_WRITE \| REQ_SYNC \| REQ_IDLE;
	if (req->cmd->rw.control & cpu_to_le16(NVME_RW_FUA))
	opf \|= REQ_FUA;
	iter_flags = SG_MITER_TO_SG;
	} else {
	opf = REQ_OP_READ;
	iter_flags = SG_MITER_FROM_SG;
	}

	if (is_pci_p2pdma_page(sg_page(req->sg)))
	opf \|= REQ_NOMERGE;

	sector = nvmet_lba_to_sect(req->ns, req->cmd->rw.slba);

	if (nvmet_use_inline_bvec(req)) {
	bio = &req->b.inline_bio;
	bio_init(bio, req->ns->bdev, req->inline_bvec,
	ARRAY_SIZE(req->inline_bvec), opf);
	} else {
	bio = bio_alloc(req->ns->bdev, bio_max_segs(sg_cnt), opf,
	GFP_KERNEL);
	}
	bio->bi_iter.bi_sector = sector;
	bio->bi_private = req;
	bio->bi_end_io = nvmet_bio_done;

	blk_start_plug(&plug);
	if (req->metadata_len)
	sg_miter_start(&prot_miter, req->metadata_sg,
	req->metadata_sg_cnt, iter_flags);

	for_each_sg(req->sg, sg, req->sg_cnt, i) {
	while (bio_add_page(bio, sg_page(sg), sg->length, sg->offset)
	!= sg->length) {
	struct bio *prev = bio;

	if (req->metadata_len) {
	rc = nvmet_bdev_alloc_bip(req, bio,
	&prot_miter);
	if (unlikely(rc)) {
	bio_io_error(bio);
	return;
	}
	}

	bio = bio_alloc(req->ns->bdev, bio_max_segs(sg_cnt),
	opf, GFP_KERNEL);
	bio->bi_iter.bi_sector = sector;

	bio_chain(bio, prev);
	submit_bio(prev);
	}

	sector += sg->length >> 9;
	sg_cnt--;
	}

	if (req->metadata_len) {
	rc = nvmet_bdev_alloc_bip(req, bio, &prot_miter);
	if (unlikely(rc)) {
	bio_io_error(bio);
	return;
	}
	}

	submit_bio(bio);
	blk_finish_plug(&plug);
	}

	static void nvmet_bdev_execute_flush(struct nvmet_req *req)
	{
	struct bio *bio = &req->b.inline_bio;

	if (!nvmet_check_transfer_len(req, 0))
	return;

	bio_init(bio, req->ns->bdev, req->inline_bvec,
	ARRAY_SIZE(req->inline_bvec), REQ_OP_WRITE \| REQ_PREFLUSH);
	bio->bi_private = req;
	bio->bi_end_io = nvmet_bio_done;

	submit_bio(bio);
	}

	u16 nvmet_bdev_flush(struct nvmet_req *req)
	{
	if (blkdev_issue_flush(req->ns->bdev))
	return NVME_SC_INTERNAL \| NVME_SC_DNR;
	return 0;
	}

	static u16 nvmet_bdev_discard_range(struct nvmet_req *req,
	struct nvme_dsm_range range, struct bio *bio)
	{
	struct nvmet_ns *ns = req->ns;
	int ret;

	ret = __blkdev_issue_discard(ns->bdev,
	nvmet_lba_to_sect(ns, range->slba),
	le32_to_cpu(range->nlb) << (ns->blksize_shift - 9),
	GFP_KERNEL, bio);
	if (ret && ret != -EOPNOTSUPP) {
	req->error_slba = le64_to_cpu(range->slba);
	return errno_to_nvme_status(req, ret);
	}
	return NVME_SC_SUCCESS;
	}

	static void nvmet_bdev_execute_discard(struct nvmet_req *req)
	{
	struct nvme_dsm_range range;
	struct bio *bio = NULL;
	int i;
	u16 status;

	for (i = 0; i <= le32_to_cpu(req->cmd->dsm.nr); i++) {
	status = nvmet_copy_from_sgl(req, i * sizeof(range), &range,
	sizeof(range));
	if (status)
	break;

	status = nvmet_bdev_discard_range(req, &range, &bio);
	if (status)
	break;
	}

	if (bio) {
	bio->bi_private = req;
	bio->bi_end_io = nvmet_bio_done;
	if (status)
	bio_io_error(bio);
	else
	submit_bio(bio);
	} else {
	nvmet_req_complete(req, status);
	}
	}

	static void nvmet_bdev_execute_dsm(struct nvmet_req *req)
	{
	if (!nvmet_check_data_len_lte(req, nvmet_dsm_len(req)))
	return;

	switch (le32_to_cpu(req->cmd->dsm.attributes)) {
	case NVME_DSMGMT_AD:
	nvmet_bdev_execute_discard(req);
	return;
	case NVME_DSMGMT_IDR:
	case NVME_DSMGMT_IDW:
	default:
	/* Not supported yet */
	nvmet_req_complete(req, 0);
	return;
	}
	}

	static void nvmet_bdev_execute_write_zeroes(struct nvmet_req *req)
	{
	struct nvme_write_zeroes_cmd *write_zeroes = &req->cmd->write_zeroes;
	struct bio *bio = NULL;
	sector_t sector;
	sector_t nr_sector;
	int ret;

	if (!nvmet_check_transfer_len(req, 0))
	return;

	sector = nvmet_lba_to_sect(req->ns, write_zeroes->slba);
	nr_sector = (((sector_t)le16_to_cpu(write_zeroes->length) + 1) <<
	(req->ns->blksize_shift - 9));

	ret = __blkdev_issue_zeroout(req->ns->bdev, sector, nr_sector,
	GFP_KERNEL, &bio, 0);
	if (bio) {
	bio->bi_private = req;
	bio->bi_end_io = nvmet_bio_done;
	submit_bio(bio);
	} else {
	nvmet_req_complete(req, errno_to_nvme_status(req, ret));
	}
	}

	u16 nvmet_bdev_parse_io_cmd(struct nvmet_req *req)
	{
	switch (req->cmd->common.opcode) {
	case nvme_cmd_read:
	case nvme_cmd_write:
	req->execute = nvmet_bdev_execute_rw;
	if (req->sq->ctrl->pi_support && nvmet_ns_has_pi(req->ns))
	req->metadata_len = nvmet_rw_metadata_len(req);
	return 0;
	case nvme_cmd_flush:
	req->execute = nvmet_bdev_execute_flush;
	return 0;
	case nvme_cmd_dsm:
	req->execute = nvmet_bdev_execute_dsm;
	return 0;
	case nvme_cmd_write_zeroes:
	req->execute = nvmet_bdev_execute_write_zeroes;
	return 0;
	default:
	return nvmet_report_invalid_opcode(req);
	}
	}