> > If we don't care about opening up fanout groups to ETH_P_NONE, then > patch v2 seems sufficient. If explicitly blocking this, the ENXIO > return can be added, but ideally without touching the other lines. I don't think that allowing ETH_P_NONE is relevant. In my opinion the 2 options that should be considered to fail fanout_add are: 1. Testing proto == 0 2. Testing proto == 0 || ifindex == -1 The only corner case that is caught by [2] and missed by [1] is the "unlisted" case during do_bind. It is such a rare case that probably no one will ever encounter bind "unlisted" followed by FANOUT_ADD. And this is not a dangerous corner case that leads to system crash. However, being a purist, I see the major goal of code review to promote correctness by identifying corner cases while improving style is a secondary priority. Since we did identify this corner case in our discussion I think we should still use [2]. I don't consider the code complex. In fact, to me, the ifindex clause is a more understandable direct reason for failure than the proto which is indirect. Having the ifindex clause helps figuring out the proto clause.
