[Devel] [PATCH RHEL7 COMMIT] ms/veth: add netpoll support

[Konstantin Khorenko]

The commit is pushed to "branch-rh7-3.10.0-229.7.2.vz7.9.x-ovz" and will appear at https://src.openvz.org/scm/ovz/vzkernel.git
after rh7-3.10.0-229.7.2.vz7.8.9
------>
commit b43914207091f5f42b613d43a6499bf330719ce6
Author: Andrew Vagin <avagin at openvz.org>
Date:   Wed Oct 21 18:15:12 2015 +0400

    ms/veth: add netpoll support
    
    ML: bb446c19fefd7b4435adb12a9dd7666adc5b553a
    
    https://jira.sw.ru/browse/PSBM-34959
    
    It is trivial to add netpoll support to veth, since
    it is not a stacked device, we don't need to setup and
    clean up netpoll.
    
    Reported-by: Stefan Priebe <s.priebe at profihost.ag>
    Cc: "David S. Miller" <davem at davemloft.net>
    Cc: Neil Horman <nhorman at tuxdriver.com>
    Acked-by: Neil Horman <nhorman at tuxdriver.com>
    Signed-off-by: Cong Wang <xiyou.wangcong at gmail.com>
    Acked-by: Neil Horman <nhorman at tuxdriver.com>
    Signed-off-by: David S. Miller <davem at davemloft.net>
    Signed-off-by: Andrew Vagin <avagin at openvz.org>
---
 drivers/net/veth.c | 18 ++++++++++++++++++
 1 file changed, 18 insertions(+)

diff --git a/drivers/net/veth.c b/drivers/net/veth.c
index 1d061c9..2df7170 100644
--- a/drivers/net/veth.c
+++ b/drivers/net/veth.c
@@ -314,6 +314,21 @@ static int vzethdev_net_ioctl(struct net_device *dev, struct ifreq *ifr, int cmd
 	return -ENOTTY;
 }
 
+#ifdef CONFIG_NET_POLL_CONTROLLER
+static void veth_poll_controller(struct net_device *dev)
+{
+	/* veth only receives frames when its peer sends one
+	 * Since it's a synchronous operation, we are guaranteed
+	 * never to have pending data when we poll for it so
+	 * there is nothing to do here.
+	 *
+	 * 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
+	 */
+}
+#endif	/* CONFIG_NET_POLL_CONTROLLER */
+
 static const struct net_device_ops veth_netdev_ops = {
 	.ndo_init            = veth_dev_init,
 	.ndo_open            = veth_open,
@@ -323,6 +338,9 @@ static const struct net_device_ops veth_netdev_ops = {
 	.ndo_get_stats64     = veth_get_stats64,
 	.ndo_set_mac_address = veth_mac_addr,
 	.ndo_do_ioctl        = vzethdev_net_ioctl,
+#ifdef CONFIG_NET_POLL_CONTROLLER
+	.ndo_poll_controller	= veth_poll_controller,
+#endif
 };
 
 #define VETH_FEATURES (NETIF_F_SG | NETIF_F_FRAGLIST | NETIF_F_ALL_TSO |    \