From 2a2bbf170054e2525f11e08bb36d4027d76b7bff Mon Sep 17 00:00:00 2001 From: Paolo Abeni Date: Thu, 14 Apr 2016 18:39:39 +0200 Subject: [PATCH] tun: don't require serialization lock on tx The current tun_net_xmit() implementation don't need any external lock since it relies on rcu protection for the tun data structure and on socket queue lock for skb queuing. This patch set the NETIF_F_LLTX feature bit in the tun device, so that on xmit, in absence of qdisc, no serialization lock is acquired by the caller. The user space can remove the default tun qdisc with: tc qdisc replace dev root noqueue Signed-off-by: Paolo Abeni Acked-by: Hannes Frederic Sowa Acked-by: Eric Dumazet Acked-by: Michael S. Tsirkin Signed-off-by: David S. Miller --- drivers/net/tun.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/drivers/net/tun.c b/drivers/net/tun.c index faf9297db2cf..42992dcbdda8 100644 --- a/drivers/net/tun.c +++ b/drivers/net/tun.c @@ -1796,7 +1796,7 @@ static int tun_set_iff(struct net *net, struct file *file, struct ifreq *ifr) dev->hw_features = NETIF_F_SG | NETIF_F_FRAGLIST | TUN_USER_FEATURES | NETIF_F_HW_VLAN_CTAG_TX | NETIF_F_HW_VLAN_STAG_TX; - dev->features = dev->hw_features; + dev->features = dev->hw_features | NETIF_F_LLTX; dev->vlan_features = dev->features & ~(NETIF_F_HW_VLAN_CTAG_TX | NETIF_F_HW_VLAN_STAG_TX); -- 2.20.1