// 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)
{
        /* Logical blocks per physical block, 0's based. */
        const __le16 lpp0b = to0based(bdev_physical_block_size(bdev) /
                                      bdev_logical_block_size(bdev));

        /*
         * 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 = to0based(bdev_io_min(bdev) / bdev_logical_block_size(bdev));
        /* NPWA = Namespace Preferred Write Alignment. 0's based */
        id->npwa = id->npwg;
        /* NPDG = Namespace Preferred Deallocate Granularity. 0's based */
        id->npdg = to0based(bdev_discard_granularity(bdev) /
                            bdev_logical_block_size(bdev));
        /* NPDG = Namespace Preferred Deallocate Alignment */
        id->npda = id->npdg;
        /* NOWS = Namespace Optimal Write Size */
        id->nows = to0based(bdev_io_opt(bdev) / bdev_logical_block_size(bdev));

        /* Set WZDS and DRB if device supports unmapped write zeroes */
        if (bdev_write_zeroes_unmap_sectors(bdev))
                id->dlfeat = (1 << 3) | 0x1;
}

void nvmet_bdev_ns_disable(struct nvmet_ns *ns)
{
        if (ns->bdev_file) {
                fput(ns->bdev_file);
                ns->bdev = NULL;
                ns->bdev_file = NULL;
        }
}

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

        if (!bi)
                return;

        if (bi->csum_type == BLK_INTEGRITY_CSUM_CRC) {
                ns->metadata_size = bi->metadata_size;
                if (bi->flags & BLK_INTEGRITY_REF_TAG)
                        ns->pi_type = NVME_NS_DPS_PI_TYPE1;
                else
                        ns->pi_type = NVME_NS_DPS_PI_TYPE3;
        } else {
                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_file = bdev_file_open_by_path(ns->device_path,
                                BLK_OPEN_READ | BLK_OPEN_WRITE, NULL, NULL);
        if (IS_ERR(ns->bdev_file)) {
                ret = PTR_ERR(ns->bdev_file);
                if (ret != -ENOTBLK) {
                        pr_err("failed to open block device %s: (%d)\n",
                                        ns->device_path, ret);
                }
                ns->bdev_file = NULL;
                return ret;
        }
        ns->bdev = file_bdev(ns->bdev_file);
        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))
                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 status codes used in the nvme_error_status().
         */
        switch (blk_sts) {
        case BLK_STS_NOSPC:
                status = NVME_SC_CAP_EXCEEDED | NVME_STATUS_DNR;
                req->error_loc = offsetof(struct nvme_rw_command, length);
                break;
        case BLK_STS_TARGET:
                status = NVME_SC_LBA_RANGE | NVME_STATUS_DNR;
                req->error_loc = offsetof(struct nvme_rw_command, slba);
                break;
        case BLK_STS_NOTSUPP:
                status = NVME_SC_INVALID_OPCODE | NVME_STATUS_DNR;
                req->error_loc = offsetof(struct nvme_common_command, opcode);
                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_STATUS_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;
        blk_status_t blk_status = bio->bi_status;

        nvmet_req_bio_put(req, bio);
        nvmet_req_complete(req, blk_to_nvme_status(req, blk_status));
}

#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);
        }

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

        resid = bio_integrity_bytes(bi, bio_sectors(bio));
        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 (req->cmd->rw.control & cpu_to_le16(NVME_RW_LR))
                opf |= REQ_FAILFAST_DEV;

        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 (!bdev_write_cache(req->ns->bdev)) {
                nvmet_req_complete(req, NVME_SC_SUCCESS);
                return;
        }

        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 (!bdev_write_cache(req->ns->bdev))
                return 0;

        if (blkdev_issue_flush(req->ns->bdev))
                return NVME_SC_INTERNAL | NVME_STATUS_DNR;
        return 0;
}

static void nvmet_bdev_execute_discard(struct nvmet_req *req)
{
        struct nvmet_ns *ns = req->ns;
        struct nvme_dsm_range range;
        struct bio *bio = NULL;
        sector_t nr_sects;
        int i;
        u16 status = NVME_SC_SUCCESS;

        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;

                nr_sects = le32_to_cpu(range.nlb) << (ns->blksize_shift - 9);
                __blkdev_issue_discard(ns->bdev,
                                nvmet_lba_to_sect(ns, range.slba), nr_sects,
                                GFP_KERNEL, &bio);
        }

        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);
        }
}