On Mon, Sep 23, 2013 at 6:32 PM, Simon Horman <ho...@verge.net.au> wrote: > On Mon, Sep 23, 2013 at 02:17:50PM -0700, Jesse Gross wrote: >> On Sat, Sep 21, 2013 at 10:34 PM, Simon Horman <ho...@verge.net.au> wrote: >> > On Thu, Sep 19, 2013 at 12:21:33PM -0500, Jesse Gross wrote: >> >> On Thu, Sep 19, 2013 at 10:57 AM, Simon Horman <ho...@verge.net.au> wrote: >> >> > On Mon, Sep 16, 2013 at 03:38:21PM -0500, Jesse Gross wrote: >> >> >> On Mon, Sep 9, 2013 at 12:20 AM, Simon Horman <ho...@verge.net.au> >> >> >> wrote: >> >> One other consideration in the OVS case - with recirculation we may >> >> hit this code multiple times and the difference in behavior could be >> >> surprising. However, on the other hand, we need to be careful because >> >> skb->cb is not guaranteed to be initialized to zero. >> > >> > Thanks, that is also not something that I had considered. >> > >> > I'm not sure, but I think that we can rely on skb->cb >> > not being clobbered between rounds of recirculation. >> > Or at the very least I think we could save and restore it >> > as necessary. >> >> Yes, it should be safe to assume this. >> >> > So I think if we could be careful to make sure that inner_protocol >> > is in a sane state the first time we see the skb but not >> > each time it is recirculated then I think things should work out. >> > >> > In my current implementation of recirculation the datapath >> > side is driven ovs_dp_process_received_packet(). So by my reasoning >> > above I think it would make sense to reset the inner_protocol there >> > and in ovs_packet_cmd_execute() rather than in ovs_execute_actions() >> > which each of those functions call. >> >> I think that would work, however, I wonder if it's the right place in >> general, independent of this compatibility issue. I guess it still >> seems like the ideal thing to do is to move this as close to where it >> is necessary as possible, specifically in mpls_push(). Is there a >> reason to not put it there (again, other than the out-of-tree >> compatibility issues)? > > I agree that should work, out-of-tree compatibility issues aside. > > Perhaps a solution is to have a conditional set_inner_protocol call inside > push_mpls, where the condition is that inner_protocol is zero. > And a reset_inner_protocol call earlier on, a call that sets inner_protocol > to zero only if the compatibility code is in use and thus it resides in > struct ovs_gso_cb. This call could be remove once the compatibility > code is no longer needed, that is once kernels older than 3.11 are no > longer supported.
I agree that's probably the right solution. _______________________________________________ dev mailing list dev@openvswitch.org http://openvswitch.org/mailman/listinfo/dev
