// SPDX-License-Identifier: GPL-2.0
#include <linux/bsg.h>
#include <scsi/scsi.h>
#include <scsi/scsi_ioctl.h>
#include <scsi/scsi_cmnd.h>
#include <scsi/scsi_device.h>
#include <scsi/sg.h>
#include "scsi_priv.h"

#define uptr64(val) ((void __user *)(uintptr_t)(val))

static int scsi_bsg_sg_io_fn(struct request_queue *q, struct sg_io_v4 *hdr,
                bool open_for_write, unsigned int timeout)
{
        struct scsi_cmnd *scmd;
        struct request *rq;
        struct bio *bio;
        int ret;

        if (hdr->protocol != BSG_PROTOCOL_SCSI  ||
            hdr->subprotocol != BSG_SUB_PROTOCOL_SCSI_CMD)
                return -EINVAL;
        if (hdr->dout_xfer_len && hdr->din_xfer_len) {
                pr_warn_once("BIDI support in bsg has been removed.\n");
                return -EOPNOTSUPP;
        }

        rq = scsi_alloc_request(q, hdr->dout_xfer_len ?
                                REQ_OP_DRV_OUT : REQ_OP_DRV_IN, 0);
        if (IS_ERR(rq))
                return PTR_ERR(rq);
        rq->timeout = timeout;

        scmd = blk_mq_rq_to_pdu(rq);
        scmd->cmd_len = hdr->request_len;
        if (scmd->cmd_len > sizeof(scmd->cmnd)) {
                ret = -EINVAL;
                goto out_put_request;
        }

        ret = -EFAULT;
        if (copy_from_user(scmd->cmnd, uptr64(hdr->request), scmd->cmd_len))
                goto out_put_request;
        ret = -EPERM;
        if (!scsi_cmd_allowed(scmd->cmnd, open_for_write))
                goto out_put_request;

        ret = 0;
        if (hdr->dout_xfer_len) {
                ret = blk_rq_map_user(rq->q, rq, NULL, uptr64(hdr->dout_xferp),
                                hdr->dout_xfer_len, GFP_KERNEL);
        } else if (hdr->din_xfer_len) {
                ret = blk_rq_map_user(rq->q, rq, NULL, uptr64(hdr->din_xferp),
                                hdr->din_xfer_len, GFP_KERNEL);
        }

        if (ret)
                goto out_put_request;

        bio = rq->bio;
        blk_execute_rq(rq, !(hdr->flags & BSG_FLAG_Q_AT_TAIL));

        /*
         * fill in all the output members
         */
        hdr->device_status = scmd->result & 0xff;
        hdr->transport_status = host_byte(scmd->result);
        hdr->driver_status = 0;
        if (scsi_status_is_check_condition(scmd->result))
                hdr->driver_status = DRIVER_SENSE;
        hdr->info = 0;
        if (hdr->device_status || hdr->transport_status || hdr->driver_status)
                hdr->info |= SG_INFO_CHECK;
        hdr->response_len = 0;

        if (scmd->sense_len && hdr->response) {
                int len = min_t(unsigned int, hdr->max_response_len,
                                scmd->sense_len);

                if (copy_to_user(uptr64(hdr->response), scmd->sense_buffer,
                                 len))
                        ret = -EFAULT;
                else
                        hdr->response_len = len;
        }

        if (rq_data_dir(rq) == READ)
                hdr->din_resid = scmd->resid_len;
        else
                hdr->dout_resid = scmd->resid_len;

        blk_rq_unmap_user(bio);

out_put_request:
        blk_mq_free_request(rq);
        return ret;
}

struct bsg_device *scsi_bsg_register_queue(struct scsi_device *sdev)
{
        return bsg_register_queue(sdev->request_queue, &sdev->sdev_gendev,
                        dev_name(&sdev->sdev_gendev), scsi_bsg_sg_io_fn);
}