[ovs-dev] [PATCH v3] dpif: Return ENODEV from dpif_port_query_by_*() if there's no port.

Ben Pfaff blp at ovn.org
Fri Jan 6 21:01:49 UTC 2017


On Fri, Jan 06, 2017 at 12:42:35PM -0800, Daniele Di Proietto wrote:
> bridge_delete_or_reconfigure() deletes every interface that's not dumped
> by OFPROTO_PORT_FOR_EACH().  ofproto_dpif.c:port_dump_next(), used by
> OFPROTO_PORT_FOR_EACH, checks if the ofport is in the datapath by
> calling port_query_by_name().  If port_query_by_name() returns an error,
> the dump is interrupted.  If port_query_by_name() returns ENODEV, the
> device doesn't exist and the dump can continue.
> 
> port_query_by_name() for the userspace datapath returns ENOENT instead
> of ENODEV.  This is expected by dpif_port_query_by_name(), but it's not
> handled correctly by port_dump_next().
> 
> dpif-netdev handles reconfiguration errors for an interface by deleting
> it from the datapath, so it's possible that a device is missing. When this
> happens we must make sure that port_dump_next() continues to dump other
> devices, otherwise they will be deleted and the two layers will have an
> inconsistent view.
> 
> This commit fixes the problem by returning ENODEV from the userspace
> datapath if the port doesn't exist, and by documenting this clearly in
> the dpif interfaces.
> 
> The problem was found while developing new code.
> 
> Signed-off-by: Daniele Di Proietto <diproiettod at vmware.com>
> ---
> v3: Return ENODEV instead of ENOENT from dpif-netdev. Document that ENODEV
>     means that the port doesn't exist, other error numbers indicate problems.

Acked-by: Ben Pfaff <blp at ovn.org>


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