Subject: xenbus: simplify xenbus_dev_request_and_reply()

No need to retain a local copy of the full request message, only the
type is really needed.

Signed-off-by: Jan Beulich <jbeulich@xxxxxxxxxx>

--- a/drivers/xen/xenbus/xenbus_xs.c
+++ b/drivers/xen/xenbus/xenbus_xs.c
@@ -203,10 +203,10 @@ static void transaction_resume(void)
 void *xenbus_dev_request_and_reply(struct xsd_sockmsg *msg)
 {
 	void *ret;
-	struct xsd_sockmsg req_msg = *msg;
+	enum xsd_sockmsg_type type = msg->type;
 	int err;
 
-	if (req_msg.type == XS_TRANSACTION_START)
+	if (type == XS_TRANSACTION_START)
 		transaction_start();
 
 	mutex_lock(&xs_state.request_mutex);
@@ -220,9 +220,8 @@ void *xenbus_dev_request_and_reply(struc
 
 	mutex_unlock(&xs_state.request_mutex);
 
-	if ((req_msg.type == XS_TRANSACTION_END) ||
-	    ((req_msg.type == XS_TRANSACTION_START) &&
-	     (msg->type == XS_ERROR)))
+	if ((type == XS_TRANSACTION_END) ||
+	    ((type == XS_TRANSACTION_START) && (msg->type == XS_ERROR)))
 		transaction_end();
 
 	return ret;