On Tue, Dec 19, 2017 at 07:51:02AM +0000, Ilya Lesokhin wrote: > On Monday, December 18, 2017 9:18 PM, Marcelo Ricardo Leitner wrote: > > > > + > > > + if (sk && sk_fullsock(sk) && sk->sk_offload_check) > > > > Isn't this going to hurt the fast path, checking for sk fields here? > > > > We do add code to the fast path but it seems unavoidable if you want to have > SW fallback. > The XFRM device offload also does that > http://elixir.free-electrons.com/linux/v4.14.7/source/net/core/dev.c#L3058
Right, although a bit different. It's accessing skb->sp and not the socket and depending on how compiler is doing things, the check http://elixir.free-electrons.com/linux/v4.14.7/source/net/xfrm/xfrm_device.c#L32 will help in some cases. But more importantly, all the above only exists if CONFIG_XFRM_OFFLOAD is enabled. > > The check can be optimized but I didn't want to do that before I saw that > it's an issue. > I'm also not sure what the correct solution is. > I don't like that fact that each "stateful protocol" we offload requires its > own check. > We need to think if we can find a generic way of doing it. > > Perhaps we can hold the expected netdev somewhere in the SKB and only if we > don't > Go out of the expected netdev go to a slow path that does a check for each > protocol. This could be a good switch, yes. Thanks, Marcelo
