1 files changed, 23 insertions, 1 deletions

diff --git a/drivers/net/tun.c b/drivers/net/tun.c
index 74e94054ab1a..5235f48be1be 100644
--- a/drivers/net/tun.c
+++ b/drivers/net/tun.c
@@ -460,7 +460,23 @@ static u32 tun_net_fix_features(struct net_device *dev, u32 features)
 
         return (features & tun->set_features) | (features & ~TUN_USER_FEATURES);
 }
-
+#ifdef CONFIG_NET_POLL_CONTROLLER
+static void tun_poll_controller(struct net_device *dev)
+{
+        /*
+         * Tun only receives frames when:
+         * 1) the char device endpoint gets data from user space
+         * 2) the tun socket gets a sendmsg call from user space
+         * Since both of those are syncronous operations, we are guaranteed
+         * never to have pending data when we poll for it
+         * so theres nothing to do here but return.
+         * We need this though so netpoll recognizes us as an interface that
+         * supports polling, which enables bridge devices in virt setups to
+         * still use netconsole
+         */
+        return;
+}
+#endif
 static const struct net_device_ops tun_netdev_ops = {
         .ndo_uninit             = tun_net_uninit,
         .ndo_open               = tun_net_open,
@@ -468,6 +484,9 @@ static const struct net_device_ops tun_netdev_ops = {
         .ndo_start_xmit         = tun_net_xmit,
         .ndo_change_mtu         = tun_net_change_mtu,
         .ndo_fix_features       = tun_net_fix_features,
+#ifdef CONFIG_NET_POLL_CONTROLLER
+        .ndo_poll_controller    = tun_poll_controller,
+#endif
 };
 
 static const struct net_device_ops tap_netdev_ops = {
@@ -480,6 +499,9 @@ static const struct net_device_ops tap_netdev_ops = {
         .ndo_set_multicast_list = tun_net_mclist,
         .ndo_set_mac_address    = eth_mac_addr,
         .ndo_validate_addr      = eth_validate_addr,
+#ifdef CONFIG_NET_POLL_CONTROLLER
+        .ndo_poll_controller    = tun_poll_controller,
+#endif
 };
 
 /* Initialize net device. */