1 files changed, 106 insertions, 0 deletions

diff --git a/drivers/scsi/scsi_bsg.c b/drivers/scsi/scsi_bsg.c
new file mode 100644
index 000000000000..81c3853a2a80
--- /dev/null
+++ b/drivers/scsi/scsi_bsg.c
@@ -0,0 +1,106 @@
+// 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,
+		fmode_t mode, unsigned int timeout)
+{
+	struct scsi_request *sreq;
+	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 = blk_get_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;
+
+	ret = -ENOMEM;
+	sreq = scsi_req(rq);
+	sreq->cmd_len = hdr->request_len;
+	if (sreq->cmd_len > BLK_MAX_CDB) {
+		sreq->cmd = kzalloc(sreq->cmd_len, GFP_KERNEL);
+		if (!sreq->cmd)
+			goto out_put_request;
+	}
+
+	ret = -EFAULT;
+	if (copy_from_user(sreq->cmd, uptr64(hdr->request), sreq->cmd_len))
+		goto out_free_cmd;
+	ret = -EPERM;
+	if (!scsi_cmd_allowed(sreq->cmd, mode))
+		goto out_free_cmd;
+
+	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_free_cmd;
+
+	bio = rq->bio;
+	blk_execute_rq(NULL, rq, !(hdr->flags & BSG_FLAG_Q_AT_TAIL));
+
+	/*
+	 * fill in all the output members
+	 */
+	hdr->device_status = sreq->result & 0xff;
+	hdr->transport_status = host_byte(sreq->result);
+	hdr->driver_status = 0;
+	if (scsi_status_is_check_condition(sreq->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 (sreq->sense_len && hdr->response) {
+		int len = min_t(unsigned int, hdr->max_response_len,
+					sreq->sense_len);
+
+		if (copy_to_user(uptr64(hdr->response), sreq->sense, len))
+			ret = -EFAULT;
+		else
+			hdr->response_len = len;
+	}
+
+	if (rq_data_dir(rq) == READ)
+		hdr->din_resid = sreq->resid_len;
+	else
+		hdr->dout_resid = sreq->resid_len;
+
+	blk_rq_unmap_user(bio);
+
+out_free_cmd:
+	scsi_req_free_cmd(scsi_req(rq));
+out_put_request:
+	blk_put_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);
+}