[ovs-dev] [PATCH 6/6] vxlan: Create and delete tnl_backers in type_run()

Ben Pfaff blp at nicira.com
Thu Feb 14 18:49:26 UTC 2013

On Thu, Feb 14, 2013 at 06:47:56PM +0000, Kyle Mestery (kmestery) wrote:
> On Feb 14, 2013, at 12:33 PM, Ben Pfaff <blp at nicira.com> wrote:
> > On Thu, Feb 14, 2013 at 09:37:30AM -0500, Kyle Mestery wrote:
> >> Garbage collect tnl_backers during type_run(). Add new
> >> tnl_backers if a VXLAN ports UDP port changes.
> >> 
> >> Signed-off-by: Kyle Mestery <kmestery at cisco.com>
> > 
> > The error handling here is bad.  If it fails to add or remove a port,
> > then ovs_assert() aborts the whole ovs-vswitchd process.
> > 
> I can change the asserts into something more sane.
> > But I don't fully understand the code.  It looks to me like the first
> > time we encounter a particular dp_port_name in the inner HMAP_FOR_EACH,
> > we transfer that dp_port_name from tmp_simap to backer->tnl_backers.
> > Straightforward enough.  However, I believe that the second time we
> > encounter that same dp_port_name, we will not find it in tmp_simap
> > (because we deleted it) and will therefore try to add a new port for
> > it.   I believe that will fail, because there is already a port with
> > that dst_port, and then we'll assert-fail the process.
> > 
> > Am I reading the code correctly?
> > 
> Actually, the second time the same dp_port_name is encountered,
> we first look and see if we need to reconfigure it, and then we check if
> it's already in backer->tnl_backers, which it will be since we added it
> there the first time we found it. I don't see it adding the port twice, unless
> I'm misreading it.

Looking again, you're right, thanks.

> > I've now pushed patch 1-4 to master, waiting for an ack from Jesse on
> > #5, waiting for your reply on this one.
> > 
> Thanks Ben! Let me know if you want me to modify the error handling
> behavior.

Please do, I'm not sure of the correct behavior.

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