Re: [PATCH net-next] tun: don't require serialization lock on tx
From: Paolo Abeni Date: Thu, 14 Apr 2016 18:39:39 +0200 > 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 Applied, thanks.
Re: [PATCH net-next] tun: don't require serialization lock on tx
On Thu, Apr 14, 2016 at 06:39:39PM +0200, Paolo Abeni wrote: > 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 This one seems transparent to userspace so: Acked-by: Michael S. Tsirkin > > --- > RFC -> v1 > - fixed a commit message typo, extended the comment with a >configuration hint > --- > 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 faf9297..42992dc 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); > -- > 1.8.3.1
[PATCH net-next] 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 --- RFC -> v1 - fixed a commit message typo, extended the comment with a configuration hint --- 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 faf9297..42992dc 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); -- 1.8.3.1
