sys/net/if_bridge.c
2570	It's much better than it was before. Any thoughts on making it an inline function to improve readability further? There are 8 arguments that are used in the macro: `iface`, `eh`, `bif`, `m`, `ifp`, `bifp`, `vlan` and `sc`. It seems that `vlan` and `sc` are only used when the interface is in learning mode (e.g. short period of time), so these can be derived from `m` and `ifp`, leaving 6 arguments, which can be doable. For example, something like `bool grab_our_packet(target_ifp, source_ifp, source_bifp, source_bif, &m, eh) {}` returning `true` if the packet is consumed can be an option. what do you think?

sys/net/if_bridge.c
2570	It seems that vlan and sc are only used when the interface is in learning mode (e.g. short period of time) Are you thinking of STP learning? This is a different type of learning, and by default is always enabled. I suspect that it is useful to cache at least `vlan`, in any case. I tried implementing your suggestion, but I don't know if it's much better. The problem is that there are three possible return values: 1) continue processing in ether_input(), 2) drop the packet, 3) try the next interface. So to make the control flow nice, I ended up introducing a couple of helpers. See https://reviews.freebsd.org/D38425

sys/net/if_bridge.c
2570	Are you thinking of STP learning? This is a different type of learning, and by default is always enabled. I suspect that it is useful to cache at least `vlan`, in any case. Yep, that's datapath learning and I was wrong. I tried implementing your suggestion, but I don't know if it's much better. The problem is that there are three possible return values: 1) continue processing in ether_input(), 2) drop the packet, 3) try the next interface. I'm not advocating for my approach, more trying to discuss a reasonable approach to eliminate the huge `#define`d function. So to make the control flow nice, I ended up introducing a couple of helpers. See https://reviews.freebsd.org/D38425 Thank you for doing that! From my point of view, the new code is now readable - and it looks much easier to reason about/improve.