drivers/scsi/scsi_bsg.c

   1 // SPDX-License-Identifier: GPL-2.0
   2 #include <linux/bsg.h>
   3 #include <scsi/scsi.h>
   4 #include <scsi/scsi_ioctl.h>
   5 #include <scsi/scsi_cmnd.h>
   6 #include <scsi/scsi_device.h>
   7 #include <scsi/sg.h>
   8 #include "scsi_priv.h"
   9
  10 #define uptr64(val) ((void __user *)(uintptr_t)(val))
  11
  12 static int scsi_bsg_sg_io_fn(struct request_queue *q, struct sg_io_v4 *hdr,
  13                 fmode_t mode, unsigned int timeout)
  14 {
  15         struct scsi_request *sreq;
  16         struct request *rq;
  17         struct bio *bio;
  18         int ret;
  19
  20         if (hdr->protocol != BSG_PROTOCOL_SCSI  ||
  21             hdr->subprotocol != BSG_SUB_PROTOCOL_SCSI_CMD)
  22                 return -EINVAL;
  23         if (hdr->dout_xfer_len && hdr->din_xfer_len) {
  24                 pr_warn_once("BIDI support in bsg has been removed.\n");
  25                 return -EOPNOTSUPP;
  26         }
  27
  28         rq = blk_get_request(q, hdr->dout_xfer_len ?
  29                              REQ_OP_DRV_OUT : REQ_OP_DRV_IN, 0);
  30         if (IS_ERR(rq))
  31                 return PTR_ERR(rq);
  32         rq->timeout = timeout;
  33
  34         ret = -ENOMEM;
  35         sreq = scsi_req(rq);
  36         sreq->cmd_len = hdr->request_len;
  37         if (sreq->cmd_len > BLK_MAX_CDB) {
  38                 sreq->cmd = kzalloc(sreq->cmd_len, GFP_KERNEL);
  39                 if (!sreq->cmd)
  40                         goto out_put_request;
  41         }
  42
  43         ret = -EFAULT;
  44         if (copy_from_user(sreq->cmd, uptr64(hdr->request), sreq->cmd_len))
  45                 goto out_free_cmd;
  46         ret = -EPERM;
  47         if (!scsi_cmd_allowed(sreq->cmd, mode))
  48                 goto out_free_cmd;
  49
  50         if (hdr->dout_xfer_len) {
  51                 ret = blk_rq_map_user(rq->q, rq, NULL, uptr64(hdr->dout_xferp),
  52                                 hdr->dout_xfer_len, GFP_KERNEL);
  53         } else if (hdr->din_xfer_len) {
  54                 ret = blk_rq_map_user(rq->q, rq, NULL, uptr64(hdr->din_xferp),
  55                                 hdr->din_xfer_len, GFP_KERNEL);
  56         }
  57
  58         if (ret)
  59                 goto out_free_cmd;
  60
  61         bio = rq->bio;
  62         blk_execute_rq(NULL, rq, !(hdr->flags & BSG_FLAG_Q_AT_TAIL));
  63
  64         /*
  65          * fill in all the output members
  66          */
  67         hdr->device_status = sreq->result & 0xff;
  68         hdr->transport_status = host_byte(sreq->result);
  69         hdr->driver_status = 0;
  70         if (scsi_status_is_check_condition(sreq->result))
  71                 hdr->driver_status = DRIVER_SENSE;
  72         hdr->info = 0;
  73         if (hdr->device_status || hdr->transport_status || hdr->driver_status)
  74                 hdr->info |= SG_INFO_CHECK;
  75         hdr->response_len = 0;
  76
  77         if (sreq->sense_len && hdr->response) {
  78                 int len = min_t(unsigned int, hdr->max_response_len,
  79                                         sreq->sense_len);
  80
  81                 if (copy_to_user(uptr64(hdr->response), sreq->sense, len))
  82                         ret = -EFAULT;
  83                 else
  84                         hdr->response_len = len;
  85         }
  86
  87         if (rq_data_dir(rq) == READ)
  88                 hdr->din_resid = sreq->resid_len;
  89         else
  90                 hdr->dout_resid = sreq->resid_len;
  91
  92         blk_rq_unmap_user(bio);
  93
  94 out_free_cmd:
  95         scsi_req_free_cmd(scsi_req(rq));
  96 out_put_request:
  97         blk_put_request(rq);
  98         return ret;
  99 }
 100
 101 struct bsg_device *scsi_bsg_register_queue(struct scsi_device *sdev)
 102 {
 103         return bsg_register_queue(sdev->request_queue, &sdev->sdev_gendev,
 104                         dev_name(&sdev->sdev_gendev), scsi_bsg_sg_io_fn);
 105 }