driver/user: Don't warn for DMA_NONE data direction

Some SCSI commands (for example the TEST UNIT READY command) do not
carry data and so data_direction is DMA_NONE. Patch TCMU to not print a
warning message about unknown data direction, when it is DMA_NONE.
Signed-off-by: Ilias Tsitsimpis <iliastsi@arrikto.com>
Signed-off-by: Vangelis Koukis <vkoukis@arrikto.com>
Reviewed-by: Andy Grover <agrover@redhat.com>
Signed-off-by: Nicholas Bellinger <nab@linux-iscsi.org>

drivers/target/target_core_user.c

@@ -518,8 +518,9 @@ static void tcmu_handle_completion(struct tcmu_cmd *cmd, struct tcmu_cmd_entry *
 
 	} else if (se_cmd->data_direction == DMA_TO_DEVICE) {
 		UPDATE_HEAD(udev->data_tail, cmd->data_length, udev->data_size);
-	} else {
-		pr_warn("TCMU: data direction was %d!\n", se_cmd->data_direction);
+	} else if (se_cmd->data_direction != DMA_NONE) {
+		pr_warn("TCMU: data direction was %d!\n",
+			se_cmd->data_direction);
 	}
 
 	target_complete_cmd(cmd->se_cmd, entry->rsp.scsi_status);