[SCSI] st: add st_scsi_execute helper function
st_scsi_execute is a helper function to perform SCSI commands
involving data transfer between user and kernel space (st_read and
st_write).
It's the future plan to combine this with st_scsi_kern_execute helper
function.
Signed-off-by: FUJITA Tomonori <fujita.tomonori@lab.ntt.co.jp>
Acked-by: Kai Makisara <Kai.Makisara@kolumbus.fi>
Signed-off-by: James Bottomley <James.Bottomley@HansenPartnership.com>
diff --git a/drivers/scsi/st.c b/drivers/scsi/st.c
index 9d9e4b9..084a967 100644
--- a/drivers/scsi/st.c
+++ b/drivers/scsi/st.c
@@ -475,6 +475,60 @@
kfree(streq);
}
+static void st_scsi_execute_end(struct request *req, int uptodate)
+{
+ struct st_request *SRpnt = req->end_io_data;
+ struct scsi_tape *STp = SRpnt->stp;
+
+ STp->buffer->cmdstat.midlevel_result = SRpnt->result = req->errors;
+ STp->buffer->cmdstat.residual = req->data_len;
+
+ if (SRpnt->waiting)
+ complete(SRpnt->waiting);
+
+ blk_rq_unmap_user(SRpnt->bio);
+ __blk_put_request(req->q, req);
+}
+
+static int st_scsi_execute(struct st_request *SRpnt, const unsigned char *cmd,
+ int data_direction, void *buffer, unsigned bufflen,
+ int timeout, int retries)
+{
+ struct request *req;
+ struct rq_map_data *mdata = &SRpnt->stp->buffer->map_data;
+ int err = 0;
+ int write = (data_direction == DMA_TO_DEVICE);
+
+ req = blk_get_request(SRpnt->stp->device->request_queue, write,
+ GFP_KERNEL);
+ if (!req)
+ return DRIVER_ERROR << 24;
+
+ req->cmd_type = REQ_TYPE_BLOCK_PC;
+ req->cmd_flags |= REQ_QUIET;
+
+ mdata->null_mapped = 1;
+
+ err = blk_rq_map_user(req->q, req, mdata, NULL, bufflen, GFP_KERNEL);
+ if (err) {
+ blk_put_request(req);
+ return DRIVER_ERROR << 24;
+ }
+
+ SRpnt->bio = req->bio;
+ req->cmd_len = COMMAND_SIZE(cmd[0]);
+ memset(req->cmd, 0, BLK_MAX_CDB);
+ memcpy(req->cmd, cmd, req->cmd_len);
+ req->sense = SRpnt->sense;
+ req->sense_len = 0;
+ req->timeout = timeout;
+ req->retries = retries;
+ req->end_io_data = SRpnt;
+
+ blk_execute_rq_nowait(req->q, NULL, req, 1, st_scsi_execute_end);
+ return 0;
+}
+
/* Do the scsi command. Waits until command performed if do_wait is true.
Otherwise write_behind_check() is used to check that the command
has finished. */