[PATCH net-next] xen-netfront: always set num queues if possible

["Charles (Chas) Williams" <3chas3@gmail.com>]

The xen store preserves this information across module invocations.
If you insmod netfront with two queues and later insmod again with one
queue, the backend will still believe you asked for two queues.

Signed-off-by: Chas Williams <3chas3@gmail.com>
---
 drivers/net/xen-netfront.c | 12 +++++++-----
 1 file changed, 7 insertions(+), 5 deletions(-)

diff --git a/drivers/net/xen-netfront.c b/drivers/net/xen-netfront.c
index f821a97..b53a681 100644
--- a/drivers/net/xen-netfront.c
+++ b/drivers/net/xen-netfront.c
@@ -1819,11 +1819,7 @@ again:
 		goto destroy_ring;
 	}
 
-	if (num_queues == 1) {
-		err = write_queue_xenstore_keys(&info->queues[0], &xbt, 0); /* flat */
-		if (err)
-			goto abort_transaction_no_dev_fatal;
-	} else {
+	if (xenbus_exists(xbt, dev->nodename, "multi-queue-num-queues")) {
 		/* Write the number of queues */
 		err = xenbus_printf(xbt, dev->nodename, "multi-queue-num-queues",
 				    "%u", num_queues);
@@ -1831,7 +1827,13 @@ again:
 			message = "writing multi-queue-num-queues";
 			goto abort_transaction_no_dev_fatal;
 		}
+	}
 
+	if (num_queues == 1) {
+		err = write_queue_xenstore_keys(&info->queues[0], &xbt, 0); /* flat */
+		if (err)
+			goto abort_transaction_no_dev_fatal;
+	} else {
 		/* Write the keys for each queue */
 		for (i = 0; i < num_queues; ++i) {
 			queue = &info->queues[i];
-- 
2.1.0